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  • 1.
    Arvizu, Miguel
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Wen, Rui-Tao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Primetzhofer, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Klemberg-Sapieha, Jolanta Ewa
    Martinu, Ludvik
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Galvanostatic ion de-trapping rejuvenates oxide thin films2015Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, nr 48, s. 26387-26390Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ion trapping under charge insertion-extraction is well-known to degrade the electrochemical performance of oxides. Galvano-static treatment was recently shown capable to rejuvenate the oxide, but the detailed mechanism remained uncertain. Here we report on amorphous electrochromic (EC) WO3 thin films prepared by sputtering and electrochemically cycled in a lithium-containing electrolyte under conditions leading to severe loss of charge exchange capacity and optical modulation span. Time-of-flight elastic recoil detection analysis (ToF-ERDA) documented pronounced Li+ trapping associated with the degradation of the EC properties and, importantly, that Li+ detrapping, caused by a weak constant current drawn through the film for some time, could recover the original EC performance. Thus, ToF-ERDA provided direct and unambiguous evidence for Li+ detrapping.

  • 2.
    Azuma, Tomoyuki
    et al.
    Univ Tokyo, Dept Bioengn, Bunkyo Ku, 7-3-1 Hongo, Tokyo 1138656, Japan..
    Teramura, Yuji
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Klinisk immunologi. Univ Tokyo, Dept Bioengn, Bunkyo Ku, 7-3-1 Hongo, Tokyo 1138656, Japan..
    Takai, Madoka
    Univ Tokyo, Dept Bioengn, Bunkyo Ku, 7-3-1 Hongo, Tokyo 1138656, Japan..
    Cellular Response to Non-contacting Nanoscale Sublayer: Cells Sense Several Nanometer Mechanical Property2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 17, s. 10710-10716Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cell adhesion is influenced not only from the surface property of materials but also from the mechanical properties of the nanometer sublayer just below the surface. In this study, we fabricated a well-defined diblock polymer brush composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) and 2-aminoethyl methacrylate (AEMA). The underlying layer of poly(MPC) is a highly viscous polymer, and the surface layer of poly(AEMA) is a cell-adhesive cationic polymer. The adhesion of L929 mouse fibroblasts was examined on the diblock polymer brush to see the effect of a non contacting underlying polymer layer on the cell-adhesion behavior. Cells could sense the viscoelasticity of the underlying layers at the nanometer level, although the various fabricated diblock polymer brushes had the same surface property and the functional group. Thus, we found a new factor which could control cell spread at the nanometer level, and this insight would be important to design nanoscale biomaterials and interfaces.

  • 3. Balitskii, Olexiy A.
    et al.
    Sytnyk, Mykhailo
    Stangl, Julian
    Primetzhofer, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Groiss, Heiko
    Heiss, Wolfgang
    Tuning the Localized Surface Plasmon Resonance in Cu2-xSe Nanocrystals by Postsynthetic Ligand Exchange2014Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, nr 20, s. 17770-17775Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanoparticles exhibiting localized surface plasmon resonances (LSPR) are valuable tools traditionally used in a wide field of applications including sensing, imaging, biodiagnostics and medical therapy. Plasmonics in semiconductor nanocrystals is of special interest because of the tunability of the carrier densities in semiconductors, and the possibility to couple the plasmonic resonances to quantum confined excitonic transitions. Here, colloidal Cu2-xSe nanocrystals were synthesized, whose composition was shown by Rutherford backscattering analysis and electron dispersive X-ray spectroscopy, to exhibit Cu deficiency. The latter results in p-type doping causing LSPRs, in the present case around a wavelength of 1100 nm, closely matching the indirect band gap of Cu2-xSe. By partial exchange of the organic ligands to specific electron trapping or donating species the LSPR is fine-tuned to exhibit blue or red shifts, in total up to 200 nm. This tuning not only provides a convenient tool for post synthetic adjustments of LSPRs to specific target wavelength but the sensitive dependence of the resonance wavelength on surface charges makes these nanocrystals also interesting for sensing applications, to detect analytes dressed by functional groups.

  • 4.
    Baloukas, Bill
    et al.
    Polytech Montreal, Dept Engn Phys, Montreal.
    Arvizu, Miguel A
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Wen, Rui-Tao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Vernhes, Richard
    Polytech Montreal, Dept Engn Phys, Montreal.
    Klemberg-Sapieha, Jolanta E.
    Polytech Montreal, Dept Engn Phys, Montreal.
    Martinu, Ludvik
    Polytech Montreal, Dept Engn Phys, Montreal.
    Galvanostatic Rejuvenation of Electrochromic WO3 Thin Films: Ion Trapping and Detrapping Observed by Optical Measurements and by Time-of-Flight Secondary Ion Mass Spectrometry2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 20, s. 16996-17002Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrochromic (EC) smart windows are able to decrease our energy footprint while enhancing indoor comfort and convenience. However, the limited durability of these windows, as well as their cost, result in hampered market introduction. Here, we investigate thin films of the most widely studied EC material, WO3. Specifically, we combine optical measurements (using spectrophotometry in conjunction with variable-angle spectroscopic ellipsometry) with time-of-flight secondary ion mass spectrometry and atomic force microscopy. Data were taken on films in their as-deposited state, after immersion in a Li-ion-conducting electrolyte, after severe degradation by harsh voltammetric cycling and after galvanostatic rejuvenation to regain the original EC performance. Unambiguous evidence was found for the trapping and detrapping of Li ions in the films, along with a thickness increase or decrease during degradation and rejuvenation, respectively. It was discovered that (i) the trapped ions exhibited a depth gradient; (ii) following the rejuvenation procedure, a small fraction of the Li ions remained trapped in the film and gave rise to a weak short-wavelength residual absorption; and (iii) the surface roughness of the film was larger in the degraded state than in its virgin and rejuvenated states. These data provide important insights into the degradation mechanisms of EC devices and into means of achieving improved durability.

  • 5.
    Barba, Albert
    et al.
    Univ Politecn Cataluna, Dept Mat Sci & Met Engn, Biomat Biomech & Tissue Engn Grp, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Univ Politecn Cataluna, Barcelona Res Ctr Multiscale Sci & Engn, Ave Eduard Maristany 10-14, Barcelona 08019, Spain.
    Diez-Escudero, Anna
    Univ Politecn Cataluna, Dept Mat Sci & Met Engn, Biomat Biomech & Tissue Engn Grp, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Univ Politecn Cataluna, Barcelona Res Ctr Multiscale Sci & Engn, Ave Eduard Maristany 10-14, Barcelona 08019, Spain.
    Espanol, Montserrat
    Univ Politecn Cataluna, Dept Mat Sci & Met Engn, Biomat Biomech & Tissue Engn Grp, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Univ Politecn Cataluna, Barcelona Res Ctr Multiscale Sci & Engn, Ave Eduard Maristany 10-14, Barcelona 08019, Spain.
    Bonany, Mar
    Univ Politecn Cataluna, Dept Mat Sci & Met Engn, Biomat Biomech & Tissue Engn Grp, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Univ Politecn Cataluna, Barcelona Res Ctr Multiscale Sci & Engn, Ave Eduard Maristany 10-14, Barcelona 08019, Spain.
    Maria Sadowska, Joanna
    Univ Politecn Cataluna, Dept Mat Sci & Met Engn, Biomat Biomech & Tissue Engn Grp, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Univ Politecn Cataluna, Barcelona Res Ctr Multiscale Sci & Engn, Ave Eduard Maristany 10-14, Barcelona 08019, Spain.
    Guillem-Marti, Jordi
    Univ Politecn Cataluna, Dept Mat Sci & Met Engn, Biomat Biomech & Tissue Engn Grp, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Univ Politecn Cataluna, Barcelona Res Ctr Multiscale Sci & Engn, Ave Eduard Maristany 10-14, Barcelona 08019, Spain.
    Öhman-Mägi, Caroline
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Manzanares, Maria-Cristina
    Univ Barcelona, Dept Pathol & Expt Therapeut, Human Anat & Embryol Unit, Barcelona 08907, Spain.
    Franch, Jordi
    Univ Autonoma Barcelona, Sch Vet, Small Anim Surg Dept, Bone Healing Grp, E-08193 Barcelona, Spain.
    Ginebra, Maria-Pau
    Univ Politecn Cataluna, Dept Mat Sci & Met Engn, Biomat Biomech & Tissue Engn Grp, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Univ Politecn Cataluna, Barcelona Res Ctr Multiscale Sci & Engn, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Barcelona Inst Technol BIST, Inst Bioengn Catalonia IBEC, Barcelona 08028, Spain.
    Impact of Biomimicry in the Design of Osteoinductive Bone Substitutes: Nanoscale Matters2019Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 9, s. 8818-8830Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bone apatite consists of carbonated calcium-deficient hydroxyapatite (CDHA) nanocrystals. Biomimetic routes allow fabricating synthetic bone grafts that mimic biological apatite. In this work, we explored the role of two distinctive features of biomimetic apatites, namely, nanocrystal morphology (plate vs needle-like crystals) and carbonate content, on the bone regeneration potential of CDHA scaffolds in an in vivo canine model. Both ectopic bone formation and scaffold degradation were drastically affected by the nanocrystal morphology after intramuscular implantation. Fine-CDHA foams with needle-like nanocrystals, comparable in size to bone mineral, showed a markedly higher osteoinductive potential and a superior degradation than chemically identical coarse-CDHA foams with larger plate-shaped crystals. These findings correlated well with the superior bone-healing capacity showed by the fine-CDHA scaffolds when implanted intraosseously. Moreover, carbonate doping of CDHA, which resulted in small plate-shaped nanocrystals, accelerated both the intrinsic osteoinduction and the bone healing capacity, and significantly increased the cell-mediated resorption. These results suggest that tuning the chemical composition and the nanostructural features may allow the material to enter the physiological bone remodeling cycle, promoting a tight synchronization between scaffold degradation and bone formation.

  • 6.
    Barba, Albert
    et al.
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politecnica de Catalunya.
    Diez-Escudero, Anna
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politecnica de Catalunya.
    Maazouz, Yassine
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politecnica de Catalunya.
    Rappe, Katrin
    Bone Healing Group, Small Animal Surgery Department, Veterinary School, Universitat Autonoma de Barcelona.
    Espanol, Montserrat
    Barcelona Research Center in Multiscale Science and Engineering, Universitat Politecnica de Catalunya.
    Montufar, Edgar B
    Barcelona Research Center in Multiscale Science and Engineering, Universitat Politecnica de Catalunya.
    Bonany, Mar
    Barcelona Research Center in Multiscale Science and Engineering, Universitat Politecnica de Catalunya.
    Sadowska, Joanna M
    Barcelona Research Center in Multiscale Science and Engineering, Universitat Politecnica de Catalunya.
    Guillem-Marti, Jordi
    Barcelona Research Center in Multiscale Science and Engineering, Universitat Politecnica de Catalunya.
    Öhman, Caroline
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Manzanares, Maria-Cristina
    Human Anatomy and Embryology Unit, Department of Pathology and Experimental Therapeutics, Universitat de Barcelona.
    Franch, Jordi
    Bone Healing Group, Small Animal Surgery Department, Veterinary School, Universitat Autonoma de Barcelona.
    Ginebra, Maria-Pau
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politecnica de Catalunya.
    Osteoinduction by Foamed and 3D-Printed Calcium Phosphate Scaffolds: Effect of Nanostructure and Pore Architecture2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 48, s. 41722-41736Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Some biomaterials are osteoinductive, that is, they are able to trigger the osteogenic process by inducing the differentiation of mesenchymal stem cells to the osteogenic lineage. Although the underlying mechanism is still unclear, microporosity and specific surface area (SSA) have been identified as critical factors in material-associated osteoinduction. However, only sintered ceramics, which have a limited range of porosities and SSA, have been analyzed so far. In this work, we were able to extend these ranges to the nanoscale, through the foaming and 3D-printing of biomimetic calcium phosphates, thereby obtaining scaffolds with controlled micro- and nanoporosity and with tailored macropore architectures. Calcium-deficient hydroxyapatite (CDHA) scaffolds were evaluated after 6 and 12 weeks in an ectopic-implantation canine model and compared with two sintered ceramics, biphasic calcium phosphate and β-tricalcium phosphate. Only foams with spherical, concave macropores and not 3Dprinted scaffolds with convex, prismatic macropores induced significant ectopic bone formation. Among them, biomimetic nanostructured CDHA produced the highest incidence of ectopic bone and accelerated bone formation when compared with conventional microstructured sintered calcium phosphates with the same macropore architecture. Moreover, they exhibited different bone formation patterns; in CDHA foams, the new ectopic bone progressively replaced the scaffold, whereas in sintered biphasic calcium phosphate scaffolds, bone was deposited on the surface of the material, progressively filling the pore space. In conclusion, this study demonstrates that the high reactivity of nanostructured biomimetic CDHA combined with a spherical, concave macroporosity allows the pushing of the osteoinduction potential beyond the limits of microstructured calcium phosphate ceramics.

  • 7.
    Bermejo-Velasco, Daniel
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi.
    Kadekar, Sandeep
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi.
    Tavares da Costa, Marcus Vinicius
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Oommen, Oommen P.
    Tampere Univ, Bioengn & Nanomed Lab, Fac Med & Hlth Technol, Korkeakoulunkatu 3, Tampere 33720, Finland;Tampere Univ, BioMediTech Inst, Korkeakoulunkatu 3, Tampere 33720, Finland.
    Gamstedt, E. Kristofer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Hilborn, Jöns
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi.
    Varghese, Oommen P.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi.
    First Aldol Cross-Linked Hyaluronic Acid Hydrogel: Fast and Hydrolytically Stable Hydrogel with Tissue Adhesive Properties2019Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 41, s. 38232-38239Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Currently, there are limited approaches to tailor 3D scaffolds cross-linked with a stable covalent C-C bond that does not require any catalysts or initiators. We present here the first hydrogels employing aldol condensation chemistry that exhibit exceptional physicochemical properties. We investigated the aldol-cross-linking chemistry using two types of aldehyde-modified hyaluronic acid (HA) derivatives, namely, an enolizable HA-aldehyde (HA-EaI) and a non-enolizable HA-aldehyde (HA-NaI). Hydrogels formed using HA-EaI demonstrate inferior cross linking efficiency (due to intramolecular loop formation), when compared with hydrogels formed by mixing HA-EaI and HA-NaI leading to a cross-aldol product. The change in mechanical properties as a result of cross-linking at different pH values is determined using rheological measurements and is interpreted in terms of molecular weight between cross-links (Me). The novel HA cross-aldol hydrogel demonstrate excellent hydrolytic stability and favorable mechanical properties but allow hyaluronidase-mediated enzymatic degradation. Interestingly, residual aldehyde functionality within the aldol product rendered the tissue adhesive properties by bonding two bone tissues. The aldehyde functionality also facilitated facile post-synthetic modifications with nucleophilic reagents. Finally, we demonstrate that the novel hydrogel is biocompatible with encapsulated stem cells that show a linear rate of expansion in our 3-6 days of study.

  • 8.
    Bi, Dongqin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    El-Zohry, Ahmed M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Hagfeldt, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Boschloo, Gerrit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Improved Morphology Control Using a Modified Two-Step Method for Efficient Perovskite Solar Cells2014Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, nr 21, s. 18751-18757Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A two-step wet chemical synthesis method for methylammonium lead(II) triiodide (CH3NH3PbI3) perovskite is further developed for the preparation of highly reproducible solar cells, with the following structure: fluorine-doped tin oxide (FTO)/TiO2 (compact)/TiO2 (mesoporous)/CH3NH3PbI3/spiro-OMeTAD/Ag. The morphology of the perovskite layer could be controlled by careful variation of the processing conditions. Specifically, by modifying the drying process and inclusion of a dichloromethane treatment, more uniform films could be prepared, with longer emission lifetime in the perovskite material and longer electron lifetime in solar cell devices, as well as faster electron transport and enhanced charge collection at the selective contacts. Solar cell efficiencies up to 13.5% were obtained.

  • 9.
    Boge, Lukas
    et al.
    RISE Res Inst Sweden, S-50115 Boras, Sweden;Chalmers Univ Technol, Dept Chem & Chem Engn, S-41296 Gothenburg, Sweden.
    Browning, Kathryn L.
    Univ Copenhagen, Dept Pharm, DK-2100 Copenhagen, Denmark.
    Nordström, Randi
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci.
    Campana, Mario
    Rutherford Appleton Lab, Didcot OX11 0DE, Oxon, England.
    Darngaard, Liv S. E.
    Univ Copenhagen, Dept Pharm, DK-2100 Copenhagen, Denmark.
    Caous, Josefin Seth
    RISE Res Inst Sweden, S-50115 Boras, Sweden.
    Hellsing, Maja
    RISE Res Inst Sweden, S-50115 Boras, Sweden.
    Ringstad, Lovisa
    RISE Res Inst Sweden, S-50115 Boras, Sweden.
    Andersson, Martin
    Chalmers Univ Technol, Dept Chem & Chem Engn, S-41296 Gothenburg, Sweden.
    Peptide-Loaded Cubosomes Functioning as an Antimicrobial Unit against Escherichia coil2019Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 24, s. 21314-21322Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dispersions of cubic liquid crystalline phases, also known as cubosomes, have shown great promise as delivery vehicles for a wide range of medicines. Due to their ordered structure, comprising alternating hydrophilic and hydrophobic domains, cubosomes possess unique delivery properties and compatibility with both water-soluble and-insoluble drugs. However, the drug delivery mechanism and cubosome interaction with human cells and bacteria are still poorly understood. Herein, we reveal how cubosomes loaded with the human cathelicidin antimicrobial peptide LL-37, a system with high bacteria-killing effect, interact with the bacterial membrane and provide new insights into the eradication mechanism. Combining the advanced experimental techniques neutron reflectivity and quartz crystal microbalance with dissipation monitoring, a mechanistic drug delivery model for LL-37-loaded cubosomes on bacterial mimicking bilayers was constructed. Moreover, the cubosome interaction with Escherichia coli was directly visualized using super-resolution laser scanning microscopy and cryogenic electron tomography. We could conclude that cubosomes loaded with LL-37 adsorbed and distorted bacterial membranes, providing evidence that the peptide-loaded cubosomes function as an antimicrobial unit.

  • 10.
    Cappel, Ute B.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Svanström, Sebastian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Lanzilotto, Valeria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Johansson, Fredrik O. L.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Aitola, Kerttu
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Philippe, Bertrand
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Giangrisostomi, Erika
    Helmholtz Zentrum Berlin GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Ovsyannikov, Ruslan
    Helmholtz Zentrum Berlin GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Leitner, Torsten
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Foehlisch, Alexander
    Helmholtz Zentrum Berlin GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany.;Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany..
    Svensson, Svante
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Mårtensson, Nils
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik. Uppsala Berlin Joint Lab Next Generat Photoelectr, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Boschloo, Gerrit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Lindblad, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Rensmo, Håkan
    Partially Reversible Photoinduced Chemical Changes in a Mixed-Ion Perovskite Material for Solar Cells2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 40, s. 34970-34978Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Metal halide perovskites have emerged as materials of high interest for solar energy-to-electricity conversion, and in particular, the use of mixed-ion structures has led to high power conversion efficiencies and improved stability. For this reason, it is important to develop means to obtain atomic level understanding of the photoinduced behavior of these materials including processes such as photoinduced phase separation and ion migration. In this paper, we implement a new methodology combining visible laser illumination of a mixed-ion perovskite ((FAP-bI(3))(0.85)(MAPbBr(3))(0.15)) with the element specificity and chemical sensitivity of core-level photoelectron spectroscopy. By carrying out measurements at a synchrotron beamline optimized for low X-ray fluxes, we are able to avoid sample changes due to X-ray illumination and are therefore able to monitor what sample changes are induced by visible illumination only. We find that laser illumination causes partially reversible chemistry in the surface region, including enrichment of bromide at the surface, which could be related to a phase separation into bromide- and iodide-rich phases. We also observe a partially reversible formation of metallic lead in the perovskite structure. These processes occur on the time scale of minutes during illumination. The presented methodology has a large potential for understanding light-induced chemistry in photoactive materials and could specifically be extended to systematically study the impact of morphology and composition on the photostability of metal halide perovskites.

  • 11.
    Chen, Song
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Shi, Liyang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi. Hunan Univ, Coll Biol, Changsha 410082, Hunan, Peoples R China.
    Luo, Jun
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Novel Fast-Setting Mineral Trioxide Aggregate: Its Formulation, Chemical-Physical Properties, and Cytocompatibility2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 24, s. 20334-20341Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the main drawbacks that limits the application of mineral trioxide aggregate (MTA) in dental field is its long setting time. Mineral trioxide aggregate with accelerated setting properties and excellent chemical-physical and biological properties is still required. In this study, an innovative mineral trioxide aggregate, which consists of calcium silicates, calcium aluminates, and zirconium oxide, was designed to obtain fast-setting property. The optimized formulation can achieve initial setting in 10 min and final setting in 15 min, which are much faster than commercial mineral trioxide aggregate. In addition, the optimized fast-setting MTA showed adequate radiopacity and good biocompatibility. The ion concentrations after storage in water for 1 day were 52.3 mg/L Ca, 67.7 mg/L Al, 48.8 mg/L Si, and 11.7 mg/L Mg. The hydration products of hardened cements were investigated by X-ray diffraction, scanning electron microscopy, and Fourier transform infrared, showing the accelerated setting time was due to the formation of honeycomb-like calcium silicate hydrate gel. The novel MTA could be a promising material for dental applications.

  • 12. Corkhill, Claire L.
    et al.
    Myllykyla, Emmi
    Bailey, Daniel J.
    Thornber, Stephanie M.
    Qi, Jiahui
    Maldonado, Pablo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Stennett, Martin C.
    Hamilton, Andrea
    Hyatt, Neil C.
    Contribution of Energetically Reactive Surface Features to the Dissolution of CeO2 and ThO2 Analogues for Spent Nuclear Fuel Microstructures2014Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, nr 15, s. 12279-12289Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the safety case for the geological disposal of nuclear waste, the release of radioactivity from the repository is controlled by the dissolution of the spent fuel in groundwater. There remain several uncertainties associated with understanding spent fuel dissolution, including the contribution of energetically reactive surface sites to the dissolution rate. In this study, we investigate how surface features influence the dissolution rate of synthetic CeO2 and ThO2, spent nuclear fuel analogues that approximate as closely as possible the microstructure characteristics of fuel-grade UO2 but are not sensitive to changes in oxidation state of the cation. The morphology of grain boundaries (natural features) and surface facets (specimen preparation-induced features) was investigated during dissolution. The effects of surface polishing on dissolution rate were also investigated. We show that preferential dissolution occurs at grain boundaries, resulting in grain boundary decohesion and enhanced dissolution rates. A strong crystallographic control was exerted, with high misorientation angle grain boundaries retreating more rapidly than those with low misorientation angles, which may be due to the accommodation of defects in the grain boundary structure. The data from these simplified analogue systems support the hypothesis that grain boundaries play a role in the so-called "instant release fraction" of spent fuel, and should be carefully considered, in conjunction with other chemical effects, in safety performance assessements for the geological disposal of spent fuel. Surface facets formed during the sample annealing process also exhibited a strong crystallographic control and were found to dissolve rapidly on initial contact with dissolution medium. Defects and strain induced during sample polishing caused an overestimation of the dissolution rate, by up to 3 orders of magnitude.

  • 13.
    D'Amario, Luca
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Jiang, Roger
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Cappel, Ute B.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Gibson, Elizabeth A.
    Newcastle Univ, Sch Chem, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England.
    Boschloo, Gerrit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi. Royal Inst Technol KTH, Ctr Mol Devices, Dept Chem, S-10044 Stockholm, Sweden.
    Rensmo, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Sun, Licheng
    Royal Inst Technol KTH, Ctr Mol Devices, Dept Chem, S-10044 Stockholm, Sweden.; Organ Chem Royal Inst Technol KTH, Dept Chem, S-10044 Stockholm, Sweden..
    Hammarström, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Tian, Haining
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi. Royal Inst Technol KTH, Ctr Mol Devices, Dept Chem, S-10044 Stockholm, Sweden.
    Chemical and Physical Reduction of High Valence Ni States in Mesoporous NiO Film for Solar Cell Application.2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 39, s. 33470-33477Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The most common material for dye-sensitized photocathodes is mesoporous NiO. We transformed the usual brownish NiO to be more transparent by reducing high valence Ni impurities. Two pretreatment methods have been used: chemical reduction by NaBH4 and thermal reduction by heating. The power conversion efficiency of the cell was increased by 33% through chemical treatment, and an increase in open-circuit voltage from 105 to 225 mV was obtained upon heat treatment. By optical spectroelectrochemistry, we could identify two species with characteristically different spectra assigned to Ni3+ and Ni4+. We suggest that the reduction of surface Ni3+ and Ni4+ to Ni2+ decreases the recombination reaction between holes on the NiO surface with the electrolyte. It also keeps the dye firmly on the surface, building a barrier for electrolyte recombination. This causes an increase in open-circuit photovoltage for the treated film.

  • 14.
    Doubaji, Siham
    et al.
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Ma, Lu
    Argonne Naional Laboratory.
    Asfaw, Habtom Desta
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Izanzar, Ilyasse
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Xu, Rui
    Argonne National Laboratory.
    Alami, Jones
    Mohammed VI Polytechnic University (UM6P), Ben Guerir, Morocco.
    Lu, Jun
    Argonne National Laboratory.
    Wu, Tianpin
    Argonne National Laboratory.
    Amine, Khalil
    Argonne National Laboratory.
    Edström, Kristina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.; Mohammed VI Polytech Univ UM6P, Mat Sci & Nanoengn Dept, Lot 660 Hay My Rachid, Ben Guerir 43150, Morocco..
    On the P2-NaxCo1−y(Mn2/3Ni1/3)yO2 Cathode Materials for Sodium-Ion Batteries: Synthesis, Electrochemical Performance, and Redox Processes Occurring during the Electrochemical Cycling2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 1, s. 488-501Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    P2-type NaMO2sodiated layered oxides withmixed transition metals are receiving considerable attention foruse as cathodes in sodium-ion batteries. A study on solidsolution (1−y)P2-NaxCoO2−(y)P2-NaxMn2/3Ni1/3O2(y=0,1/3, 1/2, 2/3, 1) reveals that changing the composition of thetransition metals affects the resulting structure and the stabilityof pure P2 phases at various temperatures of calcination. For 0≤y≤1.0, the P2-NaxCo(1−y)Mn2y/3Niy/3O2solid-solutioncompounds deliver good electrochemical performance whencycled between 2.0 and 4.2 V versus Na+/Na with improved capacity stability in long-term cycling, especially for electrodematerials with lower Co content (y= 1/2 and 2/3), despite lower discharge capacities being observed. The (1/2)P2-NaxCoO2−(1/2)P2-NaxMn2/3Ni1/3O2composition delivers a discharge capacity of 101.04 mAh g−1with a capacity loss of only 3% after 100cycles and a Coulombic efficiency exceeding 99.2%. Cycling this material to a higher cutoffvoltage of 4.5 V versus Na+/Naincreases the specific discharge capacity to≈140 mAh g−1due to the appearance of a well-defined high-voltage plateau, but afteronly 20 cycles, capacity retention declines to 88% and Coulombic efficiency drops to around 97%. In situ X-ray absorption near-edge structure measurements conducted on composition NaxCo1/2Mn1/3Ni1/6O2(y= 1/2) in the two potential windows studiedhelp elucidate the operating potential of each transition metal redox couple. It also reveals that at the high-voltage plateau, all ofthe transition metals are stable, raising the suspicion of possible contribution of oxygen ions in the high-voltage plateau.

  • 15.
    Dwibedi, Debasmita
    et al.
    Indian Inst Sci, Mat Res Ctr, Faraday Mat Lab, CV Raman Ave, Bangalore 560012, Karnataka, India..
    Ling, Chris D.
    Univ Sydney, Sch Chem, Bldg F11, Sydney, NSW 2006, Australia..
    Araujo, Rafael B.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Chakraborty, Sudip
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Duraisamy, Shanmughasundaram
    Indian Inst Sci, Inorgan & Phys Chem, CV Raman Ave, Bangalore 560012, Karnataka, India..
    Munichandraiah, Nookala
    Indian Inst Sci, Inorgan & Phys Chem, CV Raman Ave, Bangalore 560012, Karnataka, India..
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Barpanda, Prabeer
    Indian Inst Sci, Mat Res Ctr, Faraday Mat Lab, CV Raman Ave, Bangalore 560012, Karnataka, India..
    Ionothermal Synthesis of High-Voltage Alluaudite Na2+2xFe2-x(SO4)(3) Sodium Insertion Compound: Structural, Electronic, and Magnetic Insights2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 11, s. 6982-6991Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Exploring future cathode materials for sodium-ion batteries, alluaudite class of Na2Fe2II(SO4)(3) has been recently unveiled as a 3.8 V positive insertion candidate (Barpanda et al. Nat. Commun. 2014, 5, 4358). It forms an Fe-based polyanionic compound delivering the highest Fe-redox potential along with excellent rate kinetics and reversibility. However, like all known SO4-based insertion materials, its synthesis is cumbersome that warrants careful processing avoiding any aqueous exposure. Here, an alternate low temperature ionothermal synthesis has been described to produce the alluaudite Na2+2xFe2-xII(SO4)(3). It marks the first demonstration of solvothermal synthesis of alluaudite Na2+2xM2-xII(SO4)(3) (M = 3d metals) family of cathodes. Unlike classical solid-state route, this solvothermal route favors sustainable synthesis of homogeneous nanostructured alluaudite products at only 300 degrees C, the lowest temperature value until date. The current work reports the synthetic aspects of pristine and modified ionothermal synthesis of Na2+2xFe2-xII(SO4)(3) having tunable size (300 nm similar to 5 mu m) and morphology. It shows antiferromagnetic ordering below 12 K. A reversible capacity in excess of 80 mAh/g was obtained with good rate kinetics and cycling stability over 50 cycles. Using a synergistic approach combining experimental and ab initio DFT analysis, the structural, magnetic, electronic, and electrochemical properties and the structural limitation to extract full capacity have been described.

  • 16. Espanol, Montserrat
    et al.
    Mestres, Gemma
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Luxbacher, Thomas
    Dory, Jean-Baptiste
    Ginebra, Maria-Pau
    Impact of Porosity and Electrolyte Composition on the Surface Charge of Hydroxyapatite Biomaterials2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 1, s. 908-917Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The success or failure of a material when implanted in the body is greatly determined by the surface properties of the material and the host tissue reactions. The very first event that takes place after implantation is the interaction of soluble ions, molecules and proteins from the biological environment with the material surface leading to the formation of an adsorbed protein layer that will later influence cell attachment. In this context, the particular topography and surface charge of a material become critical as they influence the nature of the proteins that will adsorb. However, very limited information is available on the surface charge of porous substrates. Only until very recently was the determination of the zeta potential on porous membranes accurately determined. The goal of this work was to implement the previous findings for the determination of the zeta potential of a series of porous hydroxyapatite (HA) substrates and to assess how porosity affects the measurements. In addition, studies using various electrolytes were also performed to prove how the specific affinity of certain ions for HA can further impact surface charge. The results showed that all materials exhibited very similar external surface charge (approximately −23 mV), consistent with their almost identical topographies. However, the presence of interconnected pores underneath the sample surface resulted in an additional internal zeta potential that varied with the porosity content. Measurements with different electrolytes confirmed the selectivity of divalent ions for HA underlying the importance of testing biomaterials using relevant electrolytes.

  • 17. Fan, Jiandong
    et al.
    Fabrega, Cristian
    Zamani, Reza R.
    Hao, Yan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Parra, Andres
    Andreu, Teresa
    Arbiol, Jordi
    Boschloo, Gerrit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Hagfeldt, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Ramon Morante, Joan
    Cabot, Andreu
    Enhanced Photovoltaic Performance of Nanowire Dye-Sensitized Solar Cells Based on Coaxial TiO2@TiO Heterostructures with a Cobalt(II/III) Redox Electrolyte2013Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 5, nr 20, s. 9872-9877Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The growth of a TiO shell at the surface of TiO2 nanowires (NWs) allowed us to improve the power conversion efficiency of NW-based dye-sensitized solar cells (DSCs) by a factor 2.5. TiO2@TiO core-shell NWs were obtained by a two-step process: First, rutile-phase TiO2 NWs were hydrothermally grown. Second, a hongquiite-phase TiO shell was electrochemically deposited at the surface of the TiO2 NWs. Bare TiO2 and heterojunction TiO2@TiO NW-based DSCs were obtained using a cobalt(II/III) redox electrolyte and LEG4 as the dye. With this electrolyte/dye combination, DSCs with outstanding V-oc values above 900 mV were systematically obtained. While TiO2@TiO NW-based DSCs had slightly lower V-oc values than bare TiO2 NW-based DSCs, they provided 3-fold higher photocurrents, overall reaching 2.5-fold higher power conversion efficiencies. The higher photocurrents were associated with the larger surface roughness and an enhanced charge-carrier separation/transfer at the NW/dye interface.

  • 18. Fan, Jiandong
    et al.
    Hao, Yan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Cabot, Andreu
    Johansson, Erik M. J.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Boschloo, Gerrit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Hagfeldt, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Cobalt(II/III) Redox Electrolyte in ZnO Nanowire-Based Dye-Sensitized Solar Cells2013Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 5, nr 6, s. 1902-1906Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, we explore the use of cobalt complex redox shuttles in dye sensitized solar cells (DSCs) based on ZnO nanowires (NWs). Arrays of vertically aligned ZnO NWs produced by a low-cost hydrothermal method are used to fabricate DSCs with [Co(bpy)(3)](2+/3+) as electrolyte. A direct comparison of the performance of [Co(bpy)(3)](2+/3+)-based ZnO DSC with I-/I-3(-)-based ones demonstrates the higher suitability of the cobalt complex, both in terms of a larger open circuit voltage (V-OC) and a higher photocurrent. The [Co(bpy)(3)](2+/3+) electrolyte results in V-OC enhancements above 200 mV. This V-OC increase is associated to the better match between the cobalt complex redox potential and the oxidation potential of the dye. The incident photon-to-current efficiency (IPCE) enhancement is attributed to a less competitive visible light absorption of the cobalt redox couple. Thus the present study opens new opportunities to improve energy conversion efficiency in ZnO-based DSCs.

  • 19.
    Gao, Jiajia
    et al.
    KTH Royal Inst Technol, Dept Chem, Div Appl Phys Chem, SE-10044 Stockholm, Sweden.
    El-Zohry, Ahmed
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Trilaksana, Herri
    Flinders Univ S Australia, Flinders Ctr NanoScale Sci & Technol CNST, Adelaide, SA 5042, Australia.
    Gabrielsson, Erik
    Dyenamo AB, Greenhouse Labs, Tekn Ringen 38A, SE-11428 Stockholm, Sweden.
    Leandri, Valentina
    KTH Royal Inst Technol, Dept Chem, Div Appl Phys Chem, SE-10044 Stockholm, Sweden.
    Ellis, Hanna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    D'Amario, Luca
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Safdari, Majid
    KTH Royal Inst Technol, Dept Chem, Div Appl Phys Chem, SE-10044 Stockholm, Sweden.
    Gardner, James M.
    KTH Royal Inst Technol, Dept Chem, Div Appl Phys Chem, SE-10044 Stockholm, Sweden.
    Andersson, Gunther
    Flinders Univ S Australia, Flinders Ctr NanoScale Sci & Technol CNST, Adelaide, SA 5042, Australia.
    Kloo, Lars
    KTH Royal Inst Technol, Dept Chem, Div Appl Phys Chem, SE-10044 Stockholm, Sweden.
    Light-Induced Interfacial Dynamics Dramatically Improve the Photocurrent in Dye-Sensitized Solar Cells: An Electrolyte Effect2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 31, s. 26241-26247Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A significant increase in the photocurrent generation during light soaking for solar cells sensitized by the triphenylamine-based D-pi-A organic dyes (PD2 and LEG1) and mediated by cobalt bipyridine redox complexes has been observed and investigated. The crucial role of the electrolyte has been identified in the performance improvement. Control experiments based on a pretreatment strategy reveals TBP as the origin. The increase in the current and IPCE has been interpreted by the interfacial charge-transfer kinetics studies. A slow component in the injection kinetics was exposed for this system. This change explains the increase in the electron lifetime and collection efficiency. Photoelectron spectroscopic measurements show energy shifts at the dye/TiO2 interface, leading us to formulate a hypothesis with respect to an electrolyte induced dye reorganization at the surface.

  • 20. Gavagnin, Marco
    et al.
    Wanzenboeck, Heinz D.
    Wachter, Stefan
    Shawrav, Mostafa M.
    Persson, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Gunnarsson, Klas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Svedlindh, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Stoeger-Pollach, Michael
    Bertagnolli, Emmerich
    Free-Standing Magnetic Nanopillars for 3D Nanomagnet Logic2014Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, nr 22, s. 20254-20260Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanomagnet logic (NML) is a relatively new computation technology that uses arrays of shape-controlled nanomagnets to enable digital processing. Currently, conventional resist-based lithographic processes limit the design of NML circuitry to planar nanostructures with homogeneous thicknesses. Here, we demonstrate the focused electron beam induced deposition of Fe-based nanomaterial for magnetic in-plane nanowires and out-of-plane nanopillars. Three-dimensional (3D) NML was achieved based on the magnetic coupling between nanowires and nanopillars in a 3D array. Additionally, the same Fe-based nanomaterial was used to produce tilt-corrected high-aspect-ratio probes for the accurate magnetic force microscopy (MFM) analysis of the fabricated 3D NML gate arrays. The interpretation of the MFM measurements was supported by magnetic simulations using the Object Oriented MicroMagnetic Framework. Introducing vertical out-of-plane nanopillars not only increases the packing density of 3D NML but also introduces an extra magnetic degree of freedom, offering a new approach to input/output and processing functionalities in nanomagnetic computing.

  • 21.
    Gerz, Isabelle
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Lindh, E. Mattias
    Umea Univ, Dept Phys, Organ Photon & Elect Grp, SE-90187 Umea, Sweden.
    Thordarson, Pall
    Univ New South Wales, Australian Ctr Nanomed, Sch Chem, Sydney, NSW 2052, Australia;Univ New South Wales, ARC Ctr Excellence Convergent Bionano Sci & Techn, Sydney, NSW 2052, Australia.
    Edman, Ludvig
    Umea Univ, Dept Phys, Organ Photon & Elect Grp, SE-90187 Umea, Sweden.
    Kullgren, Jolla
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Mindemark, Jonas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Oligomer Electrolytes for Light-Emitting Electrochemical Cells: Influence of the End Groups on Ion Coordination, Ion Binding, and Turn-on Kinetics2019Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 43, s. 40372-40381Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The electrolyte is an essential constituent of the light-emitting electrochemical cell (LEC), since its operating mechanism is dependent on the redistribution of mobile ions in the active layer. Recent developments of new ion transporters have yielded high-performance devices, but knowledge about the interactions between the ionic species and the ion transporters and the influence of these interactions on the LEC performance is lacking. We therefore present a combined computational and experimental effort that demonstrates that the selection of the end group in a star-branched oligomeric ion transporter based on trimethylolpropane ethoxylate has a paramount influence on the ionic interactions in the electrolyte and thereby also on the performance of the corresponding LECs. With hydroxyl end groups, the the salt is strongly coordinated to the ion transporter, which leads to suppression of ion pairing, but the penalty is a hindered ion release and a slow turn-on for the LEC devices. With methoxy end groups, an intermediate coordination strength is seen together with the formation of contact ion pairs, but the LEC performance is very good with fast turn-on. Using a series of ion transporters with alkyl carbonate end groups, the ion transporter:cation coordination strength is lowered further, but the turn-on kinetics are slower than what is seen for devices comprising the methoxy end-capped ion transporter.

  • 22.
    Goktas, Mustafa
    et al.
    Friedrich Schiller Univ Jena, Inst Tech Chem & Environm Chem, Philosophenweg 7a, D-07743 Jena, Germany;Ctr Energy & Environm Chem Jena CEEC Jena, Philosophenweg 7a, D-07743 Jena, Germany.
    Bolli, Christoph
    Paul Scherrer Inst, Electrochem Lab, CH-5232 Villigen, Switzerland.
    Buchheim, Johannes
    Friedrich Schiller Univ Jena, Inst Tech Chem & Environm Chem, Philosophenweg 7a, D-07743 Jena, Germany;Ctr Energy & Environm Chem Jena CEEC Jena, Philosophenweg 7a, D-07743 Jena, Germany.
    Berg, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Novak, Petr
    Paul Scherrer Inst, Electrochem Lab, CH-5232 Villigen, Switzerland.
    Bonilla, Francisco
    CIC Energigune Parque Tecnol, C Albert Einstein 48, Vitoria 01510, Alava, Spain.
    Rojo, Teofilo
    CIC Energigune Parque Tecnol, C Albert Einstein 48, Vitoria 01510, Alava, Spain.
    Komaba, Shinichi
    Tokyo Univ Sci, Dept Appl Chem, Shinjuku Ku, 1-3 Kagurazaka, Tokyo 1628061, Japan.
    Kubota, Kei
    Tokyo Univ Sci, Dept Appl Chem, Shinjuku Ku, 1-3 Kagurazaka, Tokyo 1628061, Japan.
    Adelhelm, Philipp
    Friedrich Schiller Univ Jena, Inst Tech Chem & Environm Chem, Philosophenweg 7a, D-07743 Jena, Germany;Ctr Energy & Environm Chem Jena CEEC Jena, Philosophenweg 7a, D-07743 Jena, Germany.
    Stable and Unstable Diglyme-Based Electrolytes for Batteries with Sodium or Graphite as Electrode2019Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 36, s. 32844-32855Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study the stability of several diglyme-based electrolytes in sodium|sodium and sodium|graphite cells. The electrolyte behavior for different conductive salts [sodium trifluoromethanesulfonate (NaOTf), NaPF6, NaClO4, bis(fluorosulfonyl)imide (NaFSI), and sodium bis(trifluoromethanesulfonyl)imide (NaTFSI)] is compared and, in some cases, considerable differences are identified. Side reactions are studied with a variety of methods, including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, online electrochemical mass spectrometry, and in situ electrochemical dilatometry. For Na|Na symmetric cells as well as for Na|graphite cells, we find that NaOTf and NaPF6 are the preferred salts followed by NaClO4 and NaFSI, as the latter two lead to more side reactions and increasing impedance. NaTFSI shows the worst performance leading to poor Coulombic efficiency and cycle life. In this case, excessive side reactions lead also to a strong increase in electrode thickness during cycling. In a qualitative order, the suitability of the conductive salts can be ranked as follows: NaOTf >= NaPF6 > NaClO4 > NaFSI >> NaTFSI. Our results also explain two recent, seemingly conflicting findings on the degree of solid electrolyte interphase formation on graphite electrodes in sodium-ion batteries [Maibach, J.; ACS Appl. Mater. Interfaces 2017, 9, 12373-12381; Goktas, M.; Adv. Energy Mater. 2018, 8, 1702724]. The contradictory findings are due to the different conductive salts used in both studies.

  • 23.
    Gustafsson, Simon
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Strategies for Tailoring the Pore-Size Distribution of Virus Retention Filter Papers2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 22, s. 13759-13767Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The goal of this work is to demonstrate how the pore-size distribution of the nanocellulose-based virus-retentive filter can be tailored. The filter paper was produced using cellulose nanofibers derived from Cladophora sp. green algae using the hot-press drying at varying drying temperatures. The produced filters were characterized using scanning electron microscopy, atomic force microscopy, and N2 gas sorption analysis. Further, hydraulic permeability and retention efficiency toward surrogate 20 nm model particles (fluorescent carboxylate-modified polystyrene spheres) were assessed. It was shown that by controlling the rate of water evaporation during hot-press drying the pore-size distribution can be precisely tailored in the region between 10 and 25 nm. The mechanism of pore formation and critical parameters are discussed in detail. The results are highly valuable for development of advanced separation media, especially for virus-retentive size-exclusion filtration.

  • 24.
    Hao, Yan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Saygili, Yasemin
    Ecole Polytech Fed Lausanne, Inst Chem Sci & Engn, Lab Photomol Sci, Stn 6, CH-1015 Lausanne, Switzerland..
    Cong, Jiayan
    KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Chem, Appl Phys Chem, Teknikringen 30, SE-10044 Stockholm, Sweden..
    Eriksson, Anna
    Yang, Wenxing
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Zhang, Jinbao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Polanski, Enrico
    Ecole Polytech Fed Lausanne, Inst Chem Sci & Engn, Lab Photomol Sci, Stn 6, CH-1015 Lausanne, Switzerland..
    Nonomura, Kazuteru
    Ecole Polytech Fed Lausanne, Inst Chem Sci & Engn, Lab Photomol Sci, Stn 6, CH-1015 Lausanne, Switzerland..
    Zakeeruddin, Shaik Mohammed
    Ecole Polytech Fed Lausanne, Inst Chem Sci & Engn, Lab Photon & Interfaces, Stn 6, CH-1015 Lausanne, Switzerland.;King Abdulaziz Univ, CEAMR, Jeddah 21589, Saudi Arabia..
    Gratzel, Michael
    Ecole Polytech Fed Lausanne, Inst Chem Sci & Engn, Lab Photon & Interfaces, Stn 6, CH-1015 Lausanne, Switzerland..
    Hagfeldt, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi. Ecole Polytech Fed Lausanne, Inst Chem Sci & Engn, Lab Photomol Sci, Stn 6, CH-1015 Lausanne, Switzerland.;King Abdulaziz Univ, CEAMR, Jeddah 21589, Saudi Arabia..
    Boschloo, Gerrit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Novel Blue Organic Dye for Dye-Sensitized Solar Cells Achieving High Efficiency in Cobalt-Based Electrolytes and by Co-Sensitization2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 48, s. 32797-32804Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Blue and green dyes as well as NIR-absorbing dyes have attracted great interest because of their excellent ability of absorbing the incident photons in the red and near-infrared range region. A novel blue D-pi-A dye (Dyenamo Blue), based on the diketopyrrolopyrrole (DPP)-core, has been designed and synthesized. Assembled with the cobalt bipyridine-based electrolytes, the device with Dyenamo Blue achieved a satisfying efficiency of 7.3% under one sun (AM1.5 G). The co-sensitization strategy was further applied on this blue organic dye together with a red D-pi-A dye (D35). The successful co-sensitization outperformed a panchromatic light absorption and improved the photocurrent density; this in addition to the open-circuit potential result in an efficiency of 8.7%. The extended absorption of the sensitization and the slower recombination reaction between the blue dye and TiO2 surface inhibited by the additional red sensitizer could be the two main reasons for the higher performance. In conclusion, from the results, the highly efficient cobalt-based DSSCs could be achieved with the co-sensitization between red and blue D-pi-A organic dyes with a proper design, which showed us the possibility of applying this strategy for future high-performance solar cells.

  • 25. Hoshian, Sasha
    et al.
    Jokinen, Ville
    Hjort, Klas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Ras, Robin H. A.
    Franssila, Sami
    Amplified and Localized Photoswitching of TiO2 by Micro- and Nanostructuring2015Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, nr 28, s. 15593-15599Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fast photoswitching of wetting properties is important for the development of micro/nanofluidic systems and lab-on-a-chip devices. Here, we show how structuring the surface amplifies photoswitching properties. Atomic layer-deposited titanium dioxide (TiO2) has phototunable hydrophilic properties due to its surface chemistry, but microscale overhang pillars and additional nanoscale topography can override the chemistry and make the surface sup erhydrophobic. Three switching processes are achieved simply by controlling the UV exposure time: from (1) rolling superhydrophobic to sticky superhydrophobic (Cassie-Baxter to Wenzel), (2) sup erhydrophobic to hydrophilic, and (3) superhydrophobic to superhydrophilic after 1, 5, and 10 min of UV exposure, respectively. We report the fastest reversible switching to date: 1 min of UV exposure is enough to promote a rolling-to-sticky transition, and mild heating (30 min at 60 degrees C) is sufficient for recovery. This performance is caused by a combination of the photoswitching properties of TiO2, the micropillar overhang geometry, and surface nanostructuring. We demonstrate that the switching also can be performed locally by introducing microwriting under a water droplet.

  • 26.
    Hultqvist, Adam
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Aitola, Kerttu
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Sveinbjörnsson, Kári
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Saki, Zahra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi. Sharif Univ Technol, Tehran, Iran.
    Larsson, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Törndahl, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Johansson, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Boschloo, Gerrit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Edoff, Marika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Atomic Layer Deposition of Electron Selective SnOx and ZnO Films on Mixed Halide Perovskite: Compatibility and Performance2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 35, s. 29707-29716Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The compatibility of atomic layer deposition directly onto the mixed halide perovskite formamidinium lead iodide:methylammonium lead bromide (CH(NH2)(2), CH3NH3)Pb(I,Br)(3) (FAPbI(3):MAPbBr(3)) perovskite films is investigated by exposing the perovskite films to the full or partial atomic layer deposition processes for the electron selective layer candidates ZnO and SnOx. Exposing the samples to the heat, the vacuum, and even the counter reactant of H2O of the atomic layer deposition processes does not appear to alter the perovskite films in terms of crystallinity, but the choice of metal precursor is found to be critical. The Zn precursor Zn(C2H5)(2) either by itself or in combination with H2O during the ZnO atomic layer deposition (ALD) process is found to enhance the decomposition of the bulk of the perovskite film into PbI2 without even forming ZnO. In contrast, the Sn precursor Sn(N(CH3)(2))(4) does not seem to degrade the bulk of the perovskite film, and conformal SnOx films can successfully be grown on top of it using atomic layer deposition. Using this SnOx film as the electron selective layer in inverted perovskite solar cells results in a lower power conversion efficiency of 3.4% than the 8.4% for the reference devices using phenyl-C-70-butyric acid methyl ester. However, the devices with SnOx show strong hysteresis and can be pushed to an efficiency of 7.8% after biasing treatments. Still, these cells lacks both open circuit voltage and fill factor compared to the references, especially when thicker SnOx films are used. Upon further investigation, a possible cause of these losses could be that the perovskite/SnOx interface is not ideal and more specifically found to be rich in Sn, O, and halides, which is probably a result of the nucleation during the SnOx growth and which might introduce barriers or alter the band alignment for the transport of charge carriers.

  • 27.
    Häffner, Sara Malekkhaiat
    et al.
    Univ Copenhagen, Dept Pharm, Wound Healing Ctr, Bispebjerg Hosp, DK-2100 Copenhagen, Denmark.
    Nyström, Lina
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci.
    Browning, Kathryn L.
    Univ Copenhagen, Dept Pharm, Wound Healing Ctr, Bispebjerg Hosp, DK-2100 Copenhagen, Denmark.
    Nielsen, Hanne Mörck
    Univ Copenhagen, Dept Pharm, Wound Healing Ctr, Bispebjerg Hosp, DK-2100 Copenhagen, Denmark.
    Strömstedt, Adam A.
    Univ Copenhagen, Dept Med Chem, Wound Healing Ctr, Bispebjerg Hosp,Pharmacognosy, DK-2100 Copenhagen, Denmark.
    van der Plas, Mariena J. A.
    Univ Copenhagen, Dept Pharm, Wound Healing Ctr, Bispebjerg Hosp, DK-2100 Copenhagen, Denmark;Lund Univ, Dept Clin Sci, Div Dermatol & Venereol, SE-22184 Lund, Sweden.
    Schmidtchen, Artur
    Univ Copenhagen, Dept Biomed Sci, Wound Healing Ctr, Bispebjerg Hosp, DK-2100 Copenhagen, Denmark;Lund Univ, Dept Clin Sci, Div Dermatol & Venereol, SE-22184 Lund, Sweden.
    Malmsten, Martin
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci. Univ Copenhagen, Dept Pharm, Wound Healing Ctr, Bispebjerg Hosp, DK-2100 Copenhagen, Denmark.
    Interaction of Laponite with Membrane Components - Consequences for Bacterial Aggregation and Infection Confinement2019Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 17, s. 15389-15400Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The antimicrobial effects of Laponite nano particles with or without loading of the antimicrobial peptide LL-37 was investigated along with their membrane interactions. The study combines data from ellipsometry, circular dichroism, fluorescence spectroscopy, particle size/zeta potential measurements, and confocal microscopy. As a result of the net negative charge of Laponite, loading of net positively charged LL-37 increases with increasing pH. The peptide was found to bind primarily to the outer surface of the Laponite nanoparticles in a predominantly helical conformation, leading to charge reversal. Despite their net positive charge, peptide-loaded Laponite nanoparticles did not kill Gram-negative Escherichia coli bacteria or disrupt anionic model liposomes. They did however cause bacteria flocculation, originating from the interaction of Laponite and bacterial lipopolysaccharide (LPS). Free LL-37, in contrast, is potently antimicrobial through membrane disruption but does not induce bacterial aggregation in the concentration range investigated. Through LL-37 loading of Laponite nanoparticles, the combined effects of bacterial flocculation and membrane lysis are observed. However, bacteria aggregation seems to be limited to Gram-negative bacteria as Laponite did not cause flocculation of Gram-positive Bacillus subtilis bacteria nor did it bind to lipoteichoic acid from bacterial envelopes. Taken together, the present investigation reports several novel phenomena by demonstrating that nanoparticle charge does not invariably control membrane destabilization and by identifying the ability of anionic Laponite nanoparticles to effectively flocculate Gram-negative bacteria through LPS binding. As demonstrated in cell experiments, such aggregation results in diminished LPS-induced cell activation, thus outlining a promising approach for confinement of infection and inflammation caused by such pathogens.

  • 28.
    Jena, Naresh K.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Araujo, Rafael Barros Neves de
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Shukla, Vivekanand
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Royal Inst Technol KTH.
    Borophane as a Benchmate of Graphene: A Potential 2D Material for Anode of Li and Na-Ion Batteries2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 19, s. 16148-16158Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Borophene, single atomic-layer sheet of boron (Science 2015, 350, 1513), is a rather new entrant into the burgeoning class of 2D materials. Borophene exhibits anisotropic metallic properties whereas its hydrogenated counterpart borophane is reported to be a gapless Dirac material lying on the same bench with the celebrated graphene. Interestingly, this transition of borophane also rendered stability to it considering the fact that borophene was synthesized under ultrahigh vacuum conditions on a metallic (Ag) substrate. On the basis of first-principles density functional theory computations, we have investigated the possibilities of borophane as a potential Li/Na-ion battery anode material. We obtained a binding energy of -2.58 (-1.08 eV) eV for Li (Na)-adatom on borophane and Bader charge analysis revealed that Li(Na) atom exists in Li+(Na+) state. Further, on binding with Li/Na, borophane exhibited metallic properties as evidenced by the electronic band structure. We found that diffusion pathways for Li/Na on the borophane surface are anisotropic with x direction being the favorable one with a barrier of 0.27 and 0.09 eV, respectively. While assessing the Li-ion anode performance, we estimated that the maximum Li content is Li0.445B2H2, which gives rises to a material with a maximum theoretical specific capacity of 504 mAh/g together with an average voltage of 0.43 V versus Li/Li+. Likewise, for Na-ion the maximum theoretical capacity and average voltage were estimated to be 504 mAh/g and 0.03 V versus Na/Na+, respectively. These findings unambiguously suggest that borophane can be a potential addition to the map of Li and Na-ion anode materials and can rival some of the recently reported 2D materials including graphene.

  • 29.
    Jeong, Seung Hee
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Cruz, Javier
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Chen, Si
    Chalmers, Dept Microtechnol & Nanosci MC2, Kemivagen 9, SE-41296 Gothenburg, Sweden.
    Gravier, Laurent
    Univ Appl Sci & Arts Western Switzerland, Inst Micro & Nano Tech, CH-1401 Yverdon, Switzerland.
    Liu, Johan
    Chalmers, Dept Microtechnol & Nanosci MC2, Kemivagen 9, SE-41296 Gothenburg, Sweden.
    Wu, Zhigang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan 430074, Peoples R China.
    Hjort, Klas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Zhang, Shi-Li
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Zhang, Zhi-Bin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Stretchable thermoelectric generators metallized with liquid alloy2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 18, s. 15791-15797Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Conventional thermoelectric generators (TEGs) are normally hard, rigid, and flat. However, most objects have curvy surfaces, which require soft and even stretchable TEGs for maximizing efficiency of thermal energy harvesting. Here, soft and stretchable TEGs using conventional rigid Bi2Te3 pellets metallized with a liquid alloy is reported. The fabrication is implemented by means of a tailored layer-by-layer fabrication process. The STEGs exhibit an output power density of 40.6 mu W/cm(2) at room temperature. The STEGs are operational after being mechanically stretched-and-released more than 1000 times, thanks to the compliant contact between the liquid alloy interconnects and the rigid pellets. The demonstrated interconnect scheme will provide a new route to the development of soft and stretchable energy-harvesting avenues for a variety of emerging electronic applications.

  • 30.
    Jo, Jae Hyeon
    et al.
    Sejong Univ, Dept Nano Technol & Adv Mat Engn, Seoul, South Korea; Sejong Univ, Sejong Battery Inst, Seoul, South Korea.
    Choi, Ji Ung
    Sejong Univ, Dept Nano Technol & Adv Mat Engn, Seoul, South Korea; Sejong Univ, Sejong Battery Inst, Seoul, South Korea.
    Park, Yun Ji
    Sejong Univ, Dept Nano Technol & Adv Mat Engn, Seoul, South Korea; Sejong Univ, Sejong Battery Inst, Seoul, South Korea.
    Zhu, Jie-Fang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Yashiro, Hitoshi
    Iwate Univ, Dept Chem & Biol Sci, Morioka, Iwate, Japan.
    Myung, Seung-Taek
    Sejong Univ, Dept Nano Technol & Adv Mat Engn, Seoul, South Korea; Sejong Univ, Sejong Battery Inst, Seoul, South Korea.
    New Insight into Ethylenediaminetetraacetic Acid Tetrasodium Salt as a Sacrificing Sodium Ion Source for Sodium-Deficient Cathode Materials for Full Cells2019Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 6, s. 5957-5965Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sacrificing sodium supply sources is needed for sodium-deficient cathode materials to achieve commercialization of sodium-ion full cells using sodium-ion intercalation anode materials. Herein, the potential of ethylenediaminetetraacetic acid tetrasodium salt (EDTA-4Na) as a sacrificing sodium supply source was investigated by intimately blending it with sodium-deficient P2-type Na0.67[Al0.05Mn0.95]O2. The EDTA-4Na/Na0.67[Al0.05Mn0.95]O2 composite electrode unexpectedly exhibited an improved charge capacity of 177 mA h (g-oxide)−1 compared with the low charge capacity of 83 mA h (g-oxide)−1 for bare Na0.67[Al0.05Mn0.95]O2. The reversible capacity of an EDTA-4Na/Na0.67[Al0.05Mn0.95]O2//hard carbon full-cell system increased to 152 mA h (g-oxide)−1 at the first discharge with a Coulombic efficiency of 89%, whereas the Na0.67[Al0.05Mn0.95]O2 without EDTA-4Na delivered a discharge capacity 51 mA h g–1 because of the small charge capacity. The EDTA-4Na sacrificed itself to generate Na+ ions via oxidative decomposition by releasing four sodium ions and producing C3N as a decomposition resultant on charge. It is thought that the slight increase in discharge capacity is associated with the electroconducting nature of the C3N deposits formed on the surface of the Na0.67[Al0.05Mn0.95]O2 electrode. We elucidated the reaction mechanism and sacrificial activity of EDTA-4Na, and our findings suggest that the addition of EDTA-4Na is beneficial as an additional source of Na+ ions that contribute to the charge capacity.

  • 31.
    Li, Min
    et al.
    Beihang Univ, Dept Phys, Minist Educ, Key Lab Micronano Measurement Manipulat & Phys, Beijing 100191, Peoples R China.;Taishan Univ, Sch Phys & Elect Engn, Tai An 271021, Shandong, Peoples R China..
    Zhang, Junying
    Beihang Univ, Dept Phys, Minist Educ, Key Lab Micronano Measurement Manipulat & Phys, Beijing 100191, Peoples R China..
    Gao, Hong
    Beihang Univ, Dept Phys, Minist Educ, Key Lab Micronano Measurement Manipulat & Phys, Beijing 100191, Peoples R China..
    Li, Feng
    Taishan Univ, Sch Phys & Elect Engn, Tai An 271021, Shandong, Peoples R China..
    Lindquist, Sten-Eric
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Wu, Nianqiang
    W Virginia Univ, Dept Mech & Aerosp Engn, Morgantown, WV 26506 USA..
    Wang, Rongming
    Univ Sci & Technol Beijing, Sch Math & Phys, Beijing 100083, Peoples R China..
    Microsized BiOCl Square Nanosheets as Ultraviolet Photodetectors and Photocatalysts2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 10, s. 6662-6668Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BiOCl microstructures that include microspheres stacked by nanosheet and microsized square nanosheets, with a large lateral size of 3-5 mu m and a thickness of 35 nm (the side length/thickness ratio is similar to 100), are synthesized by a solvothermal method with the assistance of polyvinylpyrrolidone. The exposed face of the large square nanosheet is {001} facet. The BiOCl microstructures show good photocatalytic activity toward decomposition of Rhodamine B under ultraviolet-visible light irradiation. Moreover, individual microsized BiOCl square nanosheets are employed as the building block for construction of an ultraviolet photodetector. Because of its large size, thin thickness, and high surface-to-volume ratio, a BiOCl nanosheet shows high sensitivity and fast transient response to ultraviolet light in the spectral range 200-380 nm.

  • 32.
    Lindgren, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Xu, Chao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Niedzicki, Leszek
    Warsaw Univ Technol, Fac Chem, Noakowskiego 3, PL-00664 Warsaw, Poland..
    Marcinek, Marek
    Warsaw Univ Technol, Fac Chem, Noakowskiego 3, PL-00664 Warsaw, Poland..
    Gustafsson, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Björefors, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Edström, Kristina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Younesi, Reza
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    SEI Formation and Interfacial Stability of a Si Electrode in a LiTDI-Salt Based Electrolyte with FEC and VC Additives for Li-Ion Batteries2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 24, s. 15758-15766Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An electrolyte based on the new salt, lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide (LiTDI), is evaluated in combination with nano-Si composite electrodes for potential use in Li-ion batteries. The additives fluoroethylene carbonate (FEC) and vinylene carbonate (VC) are also added to the electrolyte to enable an efficient SEI formation. By employing hard X-ray photoelectron spectroscopy (HAXPES), the SEI formation and the development of the active material is probed during the first 100 cycles. With this electrolyte formulation, the Si electrode can cycle at 1200 mAh g(-1) for more than 100 cycles at a coulombic efficiency of 99%. With extended cycling, a decrease in Si particle size is observed as well as an increase in silicon oxide amount. As opposed to LiPF6 based electrolytes, this electrolyte or its decomposition products has no side reactions with the active Si material. The present results further acknowledge the positive effects of SEI forming additives. It is suggested that polycarbonates and a high LiF content are favorable components in the SEI over other kinds of carbonates formed by ethylene carbonate (EC) and dimethyl carbonate (DMC) decomposition. This work thus confirms that LiTDI in combination with the investigated additives is a promising salt for Si electrodes in future Li-ion batteries.

  • 33.
    Liu, Chenjuan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Carboni, Marco
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Brant, William
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Pan, Ruijun
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Hedman, Jonas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Zhu, Jiefang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Gustafsson, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Younesi, Reza
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    On the Stability of NaO2 in Na–O2 Batteries2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 16, s. 13534-13541Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Na–O2 batteries are regarded as promising candidates for energy storage. They have higher energy efficiency, rate capability, and chemical reversibility than Li–O2 batteries; in addition, sodium is cheaper and more abundant compared to lithium. However, inconsistent observations and instability of discharge products have inhibited the understanding of the working mechanism of this technology. In this work, we have investigated a number of factors that influence the stability of the discharge products. By means of in operando powder X-ray diffraction study, the influence of oxygen, sodium anode, salt, solvent, and carbon cathode were investigated. The Na metal anode and an ether-based solvent are the main factors that lead to the instability and decomposition of NaO2 in the cell environment. This fundamental insight brings new information on the working mechanism of Na–O2 batteries.

  • 34.
    Liu, Peng
    et al.
    KTH Royal Inst Technol, Sch Chem Biotechnol & Hlth, Dept Chem, Ctr Mol Devices,Appl Phys Chem, SE-10044 Stockholm, Sweden.
    Wang, Linqin
    KTH Royal Inst Technol, Sch Chem Biotechnol & Hlth, Dept Chem, Ctr Mol Devices,Organ Chem, SE-10044 Stockholm, Sweden.
    Karlsson, Karl Martin
    KTH Royal Inst Technol, Sch Chem Biotechnol & Hlth, Dept Chem, Ctr Mol Devices,Appl Phys Chem, SE-10044 Stockholm, Sweden.
    Hao, Yan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Gao, Jiajia
    KTH Royal Inst Technol, Sch Chem Biotechnol & Hlth, Dept Chem, Ctr Mol Devices,Appl Phys Chem, SE-10044 Stockholm, Sweden.
    Xu, Bo
    KTH Royal Inst Technol, Sch Chem Biotechnol & Hlth, Dept Chem, Ctr Mol Devices,Organ Chem, SE-10044 Stockholm, Sweden.
    Boschloo, Gerrit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Sun, Licheng
    KTH Royal Inst Technol, Sch Chem Biotechnol & Hlth, Dept Chem, Ctr Mol Devices,Organ Chem, SE-10044 Stockholm, Sweden;Dalian Univ Technol, Inst Artificial Photosynth, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Dalian 116024, Peoples R China.
    Kloo, Lars
    KTH Royal Inst Technol, Sch Chem Biotechnol & Hlth, Dept Chem, Ctr Mol Devices,Appl Phys Chem, SE-10044 Stockholm, Sweden.
    Molecular Engineering of D-pi-A Type of Blue-Colored Dyes for Highly Efficient Solid-State Dye-Sensitized Solar Cells through Co-Sensitization2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 42, s. 35946-35952Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel blue-colored organic donor-pi-acceptor sensitizer, the so-called MKA16 dye, has been employed to construct solid-state dye-sensitized solar cells (ssDSSCs). Using 2,2',7-,7'-tetrakis(N,N-di-p-methoxyphenyl-amine) 9,9'-spirobifuorene (Spiro-OMeTAD) as hole-transport material, a good conversion efficiency of 5.8% was recorded for cells based on the MKA16 dye and a high photovoltage of 840 mV in comparison with 5.6% efficiency using the known (Dyenamo Blue) dye. By co-sensitization using the orange-colored D35 dye and MKA16 together, the solid-state solar cells showed an excellent efficiency of 7.5%, with a high photocurrent of 12.41 mA cm(-2) and open-circuit voltage of 850 mV. The results show that the photocurrent of ssDSSCs can be significantly improved by co-sensitization mainly attributed to the wider light absorption range contributing to the photocurrent. In addition, results from photo-induced absorption spectroscopy show that the dye regeneration is efficient in co-sensitized solar cells. The current results possible routes of improving the design of aesthetic and highly efficient ssDSSCs.

  • 35.
    Liu, Yanyan
    et al.
    Royal Inst Technol, Dept Energy Technol, SE-10044 Stockholm, Sweden..
    Fan, Liangdong
    Shenzhen Univ, Coll Chem & Environm Engn, Shenzhen Key Lab New Lithium Ion Batteries & Meso, Shenzhen 518060, Guangdong, Peoples R China..
    Cai, Yixiao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap. Natl Univ Singapore, NUS Environm Res Inst, 1 Create Way, Singapore 138602, Singapore..
    Zhang, Wei
    Hubei Univ, Fac Phys & Elect Sci, Hubei Collaborat Innovat Ctr Adv Organ Chem Mat, Wuhan 430062, Hubei, Peoples R China..
    Wang, Baoyuan
    Hubei Univ, Fac Phys & Elect Sci, Hubei Collaborat Innovat Ctr Adv Organ Chem Mat, Wuhan 430062, Hubei, Peoples R China..
    Zhu, Bin
    Royal Inst Technol, Dept Energy Technol, SE-10044 Stockholm, Sweden.;Hubei Univ, Fac Phys & Elect Sci, Hubei Collaborat Innovat Ctr Adv Organ Chem Mat, Wuhan 430062, Hubei, Peoples R China..
    Superionic Conductivity of Sm3+, Pr3+, and Nd3+ Triple-Doped Ceria through Bulk and Surface Two-Step Doping Approach2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 28, s. 23614-23623Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sufficiently high oxygen ion conductivity of electrolyte is critical for good performance of low-temperature solid oxide fuel cells (LT-SOFCs). Notably, material conductivity, reliability, and manufacturing cost are the major barriers hindering LT-SOFC commercialization. Generally, surface properties control the physical and chemical functionalities of materials. Hereby, we report a Sm3+, Pr3+, and Nd3+ triple-doped ceria, exhibiting the highest ionic conductivity among reported doped-ceria oxides, 0.125 S cm(-1) at 600 degrees C. It was designed using a two-step wet-chemical coprecipitation method to realize a desired doping for Sm3+ at the bulk and Pr3+/Nd3+ at surface domains (abbreviated as PNSDC). The redox couple Pr3+ Pr4+ contributes to the extraordinary ionic conductivity. Moreover, the mechanism for ionic conductivity enhancement is demonstrated. The above findings reveal that a joint bulk and surface doping methodology for ceria is a feasible approach to develop new oxide-ion conductors with high impacts on advanced LT-SOFCs.

  • 36.
    Luo, Jun
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Martinez-Casado, Francisco Javier
    Max IV Laboratory, Lund University.
    Balmes, Olivier
    Max IV Laboratory, Lund University.
    Yang, Jiaojiao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Xia, Wei
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    In-situ Synchrotron X-ray Diffraction Analysis of the Setting Process of Brushite Cement: Reaction and Crystal Growth2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 41, s. 36392-36399Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Brushite cements are fast self-setting materials that can be used as bone substitute materials. Although tracing their fast setting process is a challenge, it is important for the understanding of the same, which in turn is important for the material’s further development and use in the clinics. In this study, the setting rate, phase formation, and crystal growth of brushite cements were quantitatively studied by in situ synchrotron powder X-ray diffraction (SXRD) on a time scale of seconds. The influence of reactant ratios and a retardant (citric acid) on the setting reaction were analyzed. To complement the in situ investigations, scanning electron microscopy was carried out for ex situ morphological evolution of crystals. The initial reaction followed a four-step process, including a fast nucleation induction period, nucleation, crystal growth, and completion of the setting. The brushite crystal size grew up to the micro scale within 1 min, and the brushite content increased linearly after the nucleation until all monocalcium phosphate monohydrate (MCPM; Ca(H2PO4)2·H2O) had dissolved within minutes, followed by a slow increase until the end of the monitoring. By adjusting the MCPM to the β-tricalcium phosphate (β-TCP, β-Ca3(PO4)2) ratio in the starting powders, the brushite/monetite ratio in the cements could be modified. In the presence of citric acid, the formation of brushite nuclei was not significantly retarded, whereas the increase in brushite content and the growth of crystal size were effectively hindered. The amount of monetite also increased by adding citric acid. This is the first time that the brushite setting process has been characterized in the first seconds and minutes of the reaction by SXRD.

  • 37.
    Ma, Yue
    et al.
    Northwestern Polytech Univ, Sch Mat Sci & Engn, State Key Lab Solidificat Proc, Ctr Nano Energy Mat, Xian 710072, Shaanxi, Peoples R China.
    Tai, Cheuk-Wai
    Stockholm Univ, Arrhenius Lab, Dept Mat & Environm Chem, SE-10691 Stockholm, Sweden.
    Li, Shaowen
    Northwestern Polytech Univ, Sch Mat Sci & Engn, State Key Lab Solidificat Proc, Ctr Nano Energy Mat, Xian 710072, Shaanxi, Peoples R China.
    Edström, Kristina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Wei, Bingqing
    Univ Delaware, Dept Mech Engn, Newark, DE 19716 USA.
    Multiscale Interfacial Strategy to Engineer Mixed Metal-Oxide Anodes toward Enhanced Cycling Efficiency2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 23, s. 20095-20105Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Interconnected macro/mesoporous structures of mixed metal oxide (MMO) are developed on nickel foam as freestanding anodes for Li-ion batteries. The sustainable production is realized via a wet chemical etching process with bio-friendly chemicals. By means of divalent iron doping during an in situ recrystallization process, the as-developed MMO anodes exhibit enhanced levels of cycling efficiency. Furthermore, this atomic-scale modification coherently synergizes with the encapsulation layer across a micrometer scale. During this step, we develop a quasi-gel-state tri-copolymer, i.e., F127-resorcinol-melamine, as the N-doped carbon source to regulate the interfacial chemistry of the MMO electrodes. Electrochemical tests of the modified FexN1-xO@NC-NiF anode in both half-cell and full-cell configurations unravel the favorable suppression of the irreversible capacity loss and satisfactory cyclability at the high rates. This study highlights a proof-of-concept modification strategy across multiple scales to govern the interfacial chemical process of the electrodes toward better reversibility.

  • 38.
    Maibach, Julia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Jeschull, Fabian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Brandell, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Edström, Kristina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Valvo, Mario
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Surface Layer Evolution on Graphite During Electrochemical Sodium-tetraglyme Co-intercalation2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 14, s. 12373-12381Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One obstacle in sodium ion batteries is the lack of suitable anode materials. As recently shown, the most common anode material of the state of the art lithium ion batteries, graphite, can be used for sodium ion storage as well, if ether based electrolyte solvents are used. These solvents cointercalate with the sodium ions leading to the highly reversible formation of ternary graphite intercalation compounds (t-GIC). In order for the solvent cointercalation to work efficiently, it is expected that only a very thin surface layer forms during electrochemical cycling. In this article, we therefore present the first dedicated study of the surface layer evolution on t-QICs using soft X-ray photoelectron spectroscopy. This technique with its inherent high surface sensitivity and low probing depth is an ideal tool to study the underlying interfacial reactions during the sodiation and desodiation of graphite. In this report, we apply this approach to graphite composite electrodes cycled in Na half cells with a 1 M sodium bis(fluorosulfonyl)imide/tetraethylene glycol dimethyl ether (NaFSI/TEG-DME) electrolyte. We have found a surface layer on the cycled electrodes, mainly composed of salt decomposition products and hydrocarbons, in line with irreversible capacity losses observed in the electrochemical cycling. Although this surface layer does not seem to block cointercalation completely, it seems to affect its efficiency resulting in a low Coulombic efficiency of the studied battery system.

  • 39.
    Makaraviciute, Asta
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Xu, Xingxing
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Nyholm, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Zhang, Zhen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Systematic approach to the development of microfabricated biosensors: relationship between the gold surface pretreatment and thiolated molecule binding2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 31, s. 26610-26621Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Despite the increasing popularity of microfabricated biosensors due to advances in technologic and surface functionalization strategies, their successful implementation is partially inhibited by the lack of consistency in their analytical characteristics. One of the main causes for the discrepancies is the absence of a systematic and comprehensive approach to surface functionalization. In this article microfabricated gold electrodes aimed at biosensor development have been systematically characterized in terms of surface pretreatment, thiolated molecule binding, and reproducibility by means of X-ray photoelectron scattering (XPS) and cyclic voltammetry (CV). It has been shown that after SU-8 photolithography gold surfaces were markedly contaminated, which decreased the effective surface area and surface coverage of a model molecule mercaptohexanol (MCH). Three surface pretreatment methods compatible with microfabricated devices were compared. The investigated methods were (i) cyclic voltammetry in dilute H2SO4, (ii) gentle basic piranha followed by linear sweep voltammetry in dilute KOH, and (iii) oxygen plasma treatment followed by incubation in ethanol. It was shown that all three methods significantly decreased the contamination and increased MCH surface coverage. Most importantly, it was also revealed that surface pretreatments may induce structural changes to the gold surfaces. Accordingly, these alterations influence the characteristics of MCH functionalization.

  • 40.
    Malyi, Oleksandr I.
    et al.
    Univ Oslo, Dept Phys, Ctr Mat Sci & Nanotechnol, NO-0316 Oslo, Norway.
    Sopiha, Kostiantyn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Persson, Clas
    Univ Oslo, Dept Phys, Ctr Mat Sci & Nanotechnol, NO-0316 Oslo, Norway.
    Energy, Phonon, and Dynamic Stability Criteria of Two-Dimensional Materials2019Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 28, s. 24876-24884Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    First-principles calculations have become a powerful tool to exclude the Edisonian approach in search of novel two-dimensional (2D) materials. However, no universal first-principles criteria to examine the realizability of hypothetical 2D materials have been established in the literature yet. Because of this, and as the calculations are always performed in an artificial simulation environment, one can unintentionally study compounds that do not exist in experiments. Although investigations of physics and chemistry of unrealizable materials can provide some fundamental knowledge, the discussion of their applications can mislead experimentalists for years and increase the gap between experimental and theoretical research. By analyzing energy convex hull, phonon spectra, and structure evolution during ab initio molecular dynamics simulations for a range of synthesized and recently proposed 2D materials, we construct energy, phonon, and dynamic stability filters that need to be satisfied before proposing novel 2D compounds. We demonstrate the power of the suggested filters for several selected 2D systems, revealing that some of them cannot be ever realized experimentally.

  • 41.
    Mao, Fang
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Taher, Mamoun
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Kryshtal, Oleksandr
    AGH Univ Sci & Technol, Int Ctr Electron Microscopy Mat Sci, Al A Mickiewicza 30, PL-30059 Krakow, Poland.;AGH Univ Sci & Technol, Fac Met Engn & Ind Comp Sci, Al A Mickiewicza 30, PL-30059 Krakow, Poland..
    Kruk, Adam
    AGH Univ Sci & Technol, Int Ctr Electron Microscopy Mat Sci, Al A Mickiewicza 30, PL-30059 Krakow, Poland.;AGH Univ Sci & Technol, Fac Met Engn & Ind Comp Sci, Al A Mickiewicza 30, PL-30059 Krakow, Poland..
    Czyrska-Filemonowicz, Aleksandra
    AGH Univ Sci & Technol, Int Ctr Electron Microscopy Mat Sci, Al A Mickiewicza 30, PL-30059 Krakow, Poland.;AGH Univ Sci & Technol, Fac Met Engn & Ind Comp Sci, Al A Mickiewicza 30, PL-30059 Krakow, Poland..
    Ottosson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Andersson, Anna M.
    ABB AB, Corp Res, SE-72178 Vasteras, Sweden..
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jansson, Ulf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Combinatorial Study of Gradient Ag-Al Thin Films: Microstructure, Phase Formation, Mechanical and Electrical Properties2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 44, s. 30635-30643Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A combinatorial approach is applied to rapidly deposit and screen Ag-Al thin films-to evaluate the mechanical, tribological, and electrical properties as a function of chemical composition. Ag-Al thin films with large continuous composition gradients (6-60 atom % Al) were deposited by a custom-designed combinatorial magnetron sputtering system. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning and transmission electron microscopy (SEM and TEM), X-ray photoelectron spectroscopy (XPS), nanoindentation, and four-point electrical resistance screening were employed to characterize the chemical composition, structure, and physical properties of the films in a time-efficient way. For low Al contents (<13 atom %), a highly (111)-textured fcc phase was formed. At higher Al contents, a (002)-textured hcp solid solution phase was formed followed by a fcc phase in the most At-rich regions. No indication of a mu phase was observed. The Ag-Al films with fcc-Ag matrix is prone to adhesive material transfer leading to a high friction coefficient (>1) and adhesive wear, similar to the behavior of pure Ag. In contrast, the hexagonal solid solution phase (from ca. 15 atom %Al) exhibited dramatically reduced friction coefficients (about 15% of that of the fcc phase) and dramatically reduced adhesive wear when tested against the pure Ag counter surface. The increase in contact resistance of the Ag Al films is limited to only 50% higher than a pure Ag reference sample at the low friction and low wear region (19-27 atom %). This suggests that a hcp Ag Al alloy can have a potential use in sliding electrical contact applications and in the future will replace pure Ag in specific electromechanical applications.

  • 42.
    McCarthy, Brian D.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Syntetisk molekylär kemi.
    Liseev, Timofey
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Syntetisk molekylär kemi.
    Beiler, Anna M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Syntetisk molekylär kemi.
    Materna, Kelly L.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Syntetisk molekylär kemi.
    Facile Orientational Control of M2L2P SURMOFs on < 100 > Silicon Substrates and Growth Mechanism Insights for Defective MOFs2019Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 41, s. 38294-38302Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Layer-by-layer growth of Cu-2(bdc)(2)(dabco) surface-mounted metal organic frameworks (SURMOFs) was investigated on silicon wafers treated with different surface anchoring molecules. Well-oriented growth along the [100] and [001] directions could be achieved with simple protocols: growth along the [100] direction was achieved by substrate pretreatment with 80 degrees C piranha, while growth along the [001] direction was enabled by only rinsing silicon with absolute ethanol. Growth along the [001] direction produced more homogeneous SURMOF films. Optimization to enhance [001]-preferred orientation growth revealed that small changes in the SURMOF growth sequence (the number of rinse steps and linker concentrations) have a noticeable impact on the final film quality and the number of misaligned crystals. This new straightforward protocol was used to successfully grow other layer pillar-type SURMOFs, including the growth of Cu-2(bdc)(2)(bipy) with simultaneous suppression of framework interpenetration.

  • 43.
    Nisar, Jawat
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Topalian, Zareh
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    De Sarkar, Abir
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    TiO2‑Based Gas Sensor: A Possible Application to SO22013Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 5, nr 17, s. 8516-8522Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fixation of SO2 molecules on anatase TiO2 surfaceswith defects have been investigated by first-principles densityfunctional theory (DFT) calculations and in situ Fourier transforminfrared (FTIR) surface spectroscopy on porous TiO2 films. Intrinsicoxygen-vacancy defects, which are formed on TiO2(001) andTiO2(101) surfaces by ultraviolet (UV) light irradiation and atelevated temperatures, are found to be most effective in anchoringthe SO2 gas molecules to the TiO2 surfaces. Both TiO2(101) andTiO2(001) surfaces with oxygen vacancies are found to exhibit higherSO2 adsorption energies in the DFT calculations. The adsorptionmechanism of SO2 is explained on the basis of electronic structure,charge transfer between the molecule and the surface, and the oxidation state of the adsorbed molecule. The theoretical findingsare corroborated by FTIR experiments. Moreover, the (001) surface with oxygen vacancies is found to bind SO2 gas moleculesmore strongly, as compared to the (101) surface. Higher concentration of oxygen vacancies on the TiO2 surfaces is found tosignificantly increase the adsorption energy. The results shed new insight into the sensing properties of TiO2-based gas sensors

  • 44.
    Norrbo, Isabella
    et al.
    Univ Turku, Dept Chem, FI-20014 Turku, Finland..
    Gluchowski, Pawel
    Polish Acad Sci, Inst Low Temp & Struct Res, PL-50422 Wroclaw, Poland..
    Hyppanen, Iko
    Univ Turku, Dept Chem, FI-20014 Turku, Finland..
    Laihinen, Tero
    Univ Turku, Dept Chem, FI-20014 Turku, Finland.;Univ Turku Grad Sch UTUGS, Doctoral Programme Phys & Chem Sci, FI-20014 Turku, Finland..
    Laukkanen, Pekka
    Univ Turku, Dept Phys & Astron, FI-20014 Turku, Finland..
    Makela, Jaakko
    Univ Turku, Dept Phys & Astron, FI-20014 Turku, Finland.;Univ Turku Grad Sch UTUGS, Doctoral Programme Phys & Chem Sci, FI-20014 Turku, Finland..
    Mamedov, Fikret
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Santos, Hellen S.
    Univ Turku, Dept Chem, FI-20014 Turku, Finland.;Univ Turku Grad Sch UTUGS, Doctoral Programme Phys & Chem Sci, FI-20014 Turku, Finland..
    Sinkkonen, Jari
    Univ Turku, Dept Chem, FI-20014 Turku, Finland..
    Tuomisto, Minnea
    Univ Turku, Dept Chem, FI-20014 Turku, Finland.;Univ Turku Grad Sch UTUGS, Doctoral Programme Phys & Chem Sci, FI-20014 Turku, Finland..
    Viinikanoja, Antti
    Univ Turku, Dept Chem, FI-20014 Turku, Finland..
    Lastusaari, Mika
    Univ Turku, Dept Chem, FI-20014 Turku, Finland.;Univ Turku, Ctr Mat & Surfaces, FI-20014 Turku, Finland..
    Mechanisms of Tenebrescence and Persistent Luminescence in Synthetic Hackmanite Na8Al6Si6O24(Cl,S)(2)2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 18, s. 11592-11602Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Synthetic hackmanites, Na8Al6Si6O24(Cl,S)(2), showing efficient purple tenebrescence and blue/white persistent luminescence were studied using different spectroscopic techniques to obtain a quantified view on the storage and release of optical energy in these materials. The persistent luminescence emitter was identified as impurity Ti3+ originating from the precursor materials used in the synthesis, and the energy storage for persistent luminescence was postulated to take place in oxygen vacancies within the aluminosilicate framework. Tenebrescence, on the other hand, was observed to function within the Na-4(Cl,S) entities located in the cavities of the aluminosilicate framework. The mechanism of persistent luminescence and tenebrescence in hackmanite is presented for the first time.

  • 45.
    Nyström, Lina
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci.
    Alvarez-Asencio, Ruben
    KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Surface & Corros Sci, SE-10044 Stockholm, Sweden.;IMDEA Nanosci, Inst Adv Studies, Madrid 28049, Spain..
    Frenning, Göran
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci.
    Saunders, Brian R.
    Univ Manchester, Sch Mat, MSS Tower, Manchester M13 9PL, Lancs, England..
    Rutland, Mark W.
    KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Surface & Corros Sci, SE-10044 Stockholm, Sweden.;SP Tech Res Inst Sweden, SP Chem Mat & Surfaces, SE-11486 Stockholm, Sweden..
    Malmsten, Martin
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci.
    Electrostatic Swelling Transitions in Surface-Bound Microgels2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 40, s. 27129-27139Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Herein, electrostatic swelling transitions of poly (ethyl acrylate-co-methacrylic acid) microgels covalently bound to silica surfaces are investigated. Confined at a solid surface, microgel swelling is anisotropically hindered and the structure is flattened to an extent dictated by pH and microgel composition. Microgel deformation under applied load is also shown to depend on microgel charge density, with the highest deformation observed at intermediate charge densities. Two modes of microgel deformation under load were observed, one elastic and one viscoelastic, related to polymer strand deformation and displacement of trapped water, respectively. Results on polymer strand dynamics reveal that the microgels are highly dynamic, as the number of strand-tip interaction points increases 4-fold during a 10 s contact time. Furthermore, finite element modeling captures these effects qualitatively and shows that stress propagation in the microgel network decays locally at the rim of contact with a solid interface or close to the tip probe. Taken together, the results demonstrate a delicate interplay between the surface and microgel which determines the structure and nanomechanical properties of the latter and needs to be controlled in applications of systems such as pH-responsive surface coatings in biomaterials.

  • 46.
    Oommen, Oommen Podiyan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi. Tampere Univ Technol, BioMediTech Inst Biosci & Med Technol, Bioengn & Nanomed Grp, Tampere 33520, Finland..
    Duehrkop, Claudia
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Klinisk immunologi.
    Nilsson, Bo
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Klinisk immunologi.
    Hilborn, Jöns
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi.
    Varghese, Oommen P.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi.
    Multifunctional Hyaluronic Acid and Chondroitin Sulfate Nanoparticles: Impact of Glycosaminoglycan Presentation on Receptor Mediated Cellular Uptake and Immune Activation2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 32, s. 20614-20624Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hyaluronic acid (HA) and chondroitin sulfate (CS) polymers are extensively used for various biomedical applications, such as for tissue engineering, drug delivery, and gene delivery. Although both these biopolymers are known to target cell surface CD44 receptors, their relative cellular targeting properties and immune activation potential have never been evaluated. In this article, we present the synthesis and characterization of novel self assembled supramolecular HA and CS nanoparticles (NPs). These NPs were developed using fluorescein as a hydrophobic component that induced amphiphilicity in biopolymers and also efficiently stabilized anticancer drug doxorubicin (DOX) promoting a near zero-order drug release. The cellular uptake and cytotoxicity studies of these NPs in different human cancer lines, namely, human colorectal carcinoma cell line HCT116 and human breast cancer cell line MCF-7 demonstrated dose dependent cytotoxicity. Interestingly, both NPs showed CD44 dependent cellular uptake with the CS DOX NP displaying higher dose-dependent cytotoxicity than the HA DOX NP in different mammalian cells tested. Immunological evaluation of these nanocarriers in an ex vivo human whole blood model revealed that unlike unmodified polymers, the HA NP and CS NP surprisingly showed platelet aggregation and thrombin antithrombin complex formation at high concentrations (0.8 mg/mL). We also observed a clear difference in early- and late-stage complement activation (C3a and sC5b-9) with CS and CS NP triggering significant complement activation at high concentrations (0.08-0.8 mg/mL), unlike HA and HA NP. These results offer new insight into designing glycosaminoglycan-based NPs and understanding their hematological responses and targeting ability.

  • 47.
    Park, Byung-wook
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Pazoki, Meysam
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Aitola, Kerttu
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Jeong, Seunghee
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Johansson, Erik M. J.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Hagfeldt, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Boschloo, Gerrit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Understanding Interfacial Charge Transfer between Metallic PEDOT Counter Electrodes and a Cobalt Redox Shuttle in Dye-Sensitized Solar Cells2014Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, nr 3, s. 2074-2079Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) doped with iron(111) tris-p-toluenesulfonate (PEDOT:Tos) having metallic conductivity was coated onto fluorine-doped tin oxide (FTO) glass and plain glass substrates and used as a counter electrode (CE) in a dye-sensitized solar cell (DSC) with a [Co(bpy)(3)](3+/2+) complex redox shuttle. DSCs with PEDOT:Tos/glass CE yielded power conversion efficiencies (PCE) of 6.3%, similar to that of DSCs with platinized FTO glass CE (6.1%). The PEDOT:Tos-based counter electrodes had 5 to 10 times lower charge-transfer resistance than the Pt/FTO CE in DSCs, as analyzed by impedance spectroscopy. More detailed studies in symmetrical CE-CE cells showed that the PEDOT:Tos layers are nanoporous. Not all internal area can be used catalytically under solar cell conditions and effective charge-transfer resistance was similar to that of Pt/FTO.

  • 48.
    Qu, Hui-Ying
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Harbin Institute of Technology, School of Chemistry and Chemical Engineering, MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage.
    Primetzhofer, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Arvizu, Miguel A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Qiu, Zhen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Cindemir, Umut
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Electrochemical Rejuvenation of Anodically Coloring Electrochromic Nickel Oxide Thin Films2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, nr 9, s. 42420-42424Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nickel oxide thin films are of major importance as anodically coloring components in electrochromic smart windows with applications in energy-efficient buildings. However, the optical performance of these films degrades upon extended electrochemical cycling, which has hampered their implementation. Here, we use a potentiostatic treatment to rejuvenate degraded nickel oxide thin films immersed in electrolytes of LiClO4 in propylene carbonate. Time-of-flight elastic recoil detection analysis provided unambiguous evidence that both Li+ ions and chlorine-based ions participate in the rejuvenation process. Our work provides new perspectives for developing ion-exchange-based devices embodying nickel oxide.

  • 49.
    Quellmalz, Arne
    et al.
    KTH Royal Inst Technol, Sch Elect Engn & Comp Sci, Dept Micro & Nanosyst, SE-10044 Stockholm, Sweden.
    Smith, Anderson D.
    KTH Royal Inst Technol, Sch Elect Engn & Comp Sci, Dept Elect, Electrum 229, SE-16440 Kista, Sweden;Chalmers Univ Technol, Dept Microtechnol & Nanosci, S-41296 Gothenburg, Sweden.
    Elgammal, Karim
    KTH Royal Inst Technol, Swedish E Sci Res Ctr SeRC, SE-10044 Stockholm, Sweden;KTH Royal Inst Technol, Sch Sci & Engn, Dept Appl Phys, Electrum 229, SE-16440 Kista, Sweden.
    Fan, Xuge
    KTH Royal Inst Technol, Sch Elect Engn & Comp Sci, Dept Micro & Nanosyst, SE-10044 Stockholm, Sweden.
    Delin, Anna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. KTH Royal Inst Technol, Swedish E Sci Res Ctr SeRC, SE-10044 Stockholm, Sweden;KTH Royal Inst Technol, Sch Sci & Engn, Dept Appl Phys, Electrum 229, SE-16440 Kista, Sweden.
    Östling, Mikael
    KTH Royal Inst Technol, Sch Elect Engn & Comp Sci, Dept Elect, Electrum 229, SE-16440 Kista, Sweden.
    Lemme, Max
    Rhein Westfal TH Aachen, Chair Elect Devices, Otto Blumenthal Str 2, D-52074 Aachen, Germany;AMO GmbH, Adv Microelect Ctr Aachen AMIGA, Otto Blumenthal Str 25, D-52074 Aachen, Germany.
    Gylfason, Kristinn B.
    KTH Royal Inst Technol, Sch Elect Engn & Comp Sci, Dept Micro & Nanosyst, SE-10044 Stockholm, Sweden.
    Niklaus, Frank
    KTH Royal Inst Technol, Sch Elect Engn & Comp Sci, Dept Micro & Nanosyst, SE-10044 Stockholm, Sweden.
    Influence of Humidity on Contact Resistance in Graphene Devices2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 48, s. 41738-41746Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The electrical contact resistance at metal-graphene interfaces can significantly degrade the properties of graphene devices and is currently hindering the full exploitation of graphene's potential. Therefore, the influence of environmental factors, such as humidity, on the metal-graphene contact resistance is of interest for all graphene devices that operate without hermetic packaging. We experimentally studied the influence of humidity on bottom-contacted chemical-vapor-deposited (CVD) graphene-gold contacts, by extracting the contact resistance from transmission line model (TLM) test structures. Our results indicate that the contact resistance is not significantly affected by changes in relative humidity (RH). This behavior is in contrast to the measured humidity sensitivity (0.059 +/- 0.011 %/% RH) of graphene's sheet resistance. In addition, we employ density functional theory (DFT) simulations to support our experimental observations. Our DFT simulation results demonstrate that the electronic structure of the graphene sheet on top of silica is much more sensitive to adsorbed water molecules than the charge density at the interface between gold and graphene. Thus, we predict no degradation of device performance by alterations in contact resistance when such contacts are exposed to humidity. This knowledge underlines that bottom-contacting of graphene is a viable approach for a variety of graphene devices and the back end of the line integration on top of conventional integrated circuits.

  • 50.
    Ren, Yi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Scragg, Jonathan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Edoff, Marika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Larsen, Jes
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Platzer-Björkman, Charlotte
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Evolution of Na-S(-O) compounds on the Cu2ZnSnS4 absorber surface and their effects on CdS thin film growth2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 28, s. 18600-18607Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Formation of Na-containing surface compounds is an important phenomenon in the Cu2ZnSnS4 (CZTS) quaternary material synthesis for solar cell applications. Still, identification of these compounds and the understanding of their potential influence on buffer layer growth and device performance are scarce. In this work, we discovered that the evolution of Na-S(-O) compounds on the CZTS surface substantially affect the solution/CZTS interface during the chemical bath deposition of CdS buffer film. We showed that Na2S negatively affects the growth of CdS, and that this compound is likely to form on the CZTS surface after annealing. It was also demonstrated that the Na2S compound can be oxidized to Na2SO4 by air exposure of the annealed CZTS surface or be removed using water dipping instead of the commonly used KCN etching process, resulting in significantly better quality of the CdS layer. Lastly, 6.5% CZTS solar cells were fabricated with air exposure treatment without incorporation of the KCN etching process. This work provides new insight into the growth of the CdS/CZTS interface for solar cell applications and opens new possibilities for improving likewise Cd-free buffer materials that are grown with a similar chemical bath deposition process.

12 1 - 50 of 85
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