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  • 1. Cong, Jiayan
    et al.
    Hao, Yan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Kloo, Lars
    Electrolytes Based on TEMPO-Co Tandem Redox Systems Outperform Single Redox Systems in Dye-sensitized Solar Cells2015In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, no 2, p. 264-268Article in journal (Refereed)
    Abstract [en]

    A new TEMPO-Co tandem redox system with TEMPO and Co(bpy)(3)(2+/3+) has been investigated for the use in dye-sensitized solar cells (DSSCs). A large open-circuit voltage (V-OC) increase, from 862 mV to 965 mV, was observed in the tandem redox system, while the short-circuit current density (J(SC)) was maintained. The conversion efficiency was observed to increase from 7.1% for cells containing the single Co(bpy)(3)(2+/3+) redox couple, to 8.4% for cells containing the TEMPO-Co tandem redox system. The reason for the increase in V-OC and overall efficiency is ascribed to the involvement of partial regeneration of the sensitizing dye molecules by TEMPO. This assumption can be verified through the observed much faster regeneration dynamics exhibited in the presence of the tandem system. Using the tandem redox system, the faster recombination problem of the single TEMPO redox couple is resolved and the mass-transport of the metal-complex-based electrolyte is also improved. This TEMPO-Co tandem system is so far the most effienct tandem redox electrolyte reported not involving iodine. The current results show a promising future for tandem system as replacements for single redox systems in electrolytes for DSSCs.

  • 2.
    Das, Biswanath
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Thapper, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Iron Pentapyridyl Complexes as Molecular WaterOxidation Catalysts: Strong Influence of a Chloride Ligandand pH in Altering the Mechanism2016In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, no 10, p. 1178-1186Article in journal (Refereed)
    Abstract [en]

    The development of molecular water oxidation catalysts basedon earth-abundant, non-noble metals is essential for artificial photosynthesis research. Iron, which is the most abundant transition metal in the earth's crust, is a prospective candidate for this purpose. Herein, we report two iron complexes based on the polypyridyl ligand Py5OH (Py5OH=pyridine-2,6-diylbis[di(pyridin-2-yl)methanol]) that can catalyse water oxidation to produce O2 in RuIII-induced (at pH 8, highest turnover number (TON)=26.5; turnover frequency (TOF)=2.2 s-1), CeIV-induced(at pH 1.5 highest TON=16; TOF=0.75 s-1) and photo-induced(at pH 8, highest TON=43.5; TOF=0.6 s-1) reactions. A chloride ligand in one of the iron complexes is shown to affect the activity strongly, improve stability and, thereby, the performance at pH 8 but it inhibits oxygen evolution at pH 1.5. The observations are consistent with a change in mechanism for catalytic water oxidation with the Fe(Py5OH) complexes between acidic (CeIV) and near-neutral pH (RuIII).

  • 3.
    Doubaji, Siham
    et al.
    Univ Cadi Ayyad, FST Marrakesh, LCME, Marrakech 40000, Morocco..
    Philippe, Bertrand
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Saadoune, Ismael
    Univ Cadi Ayyad, FST Marrakesh, LCME, Marrakech 40000, Morocco.;Univ Mohammed VI Polytech, Ctr Adv Mat, Ben Guerir, Morocco..
    Gorgoi, Mihaela
    Helmholtz Zentrum Berlin Mat & Energie, D-12489 Berlin, Germany..
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Solhy, Abderrahim
    Univ Mohammed VI Polytech, Ctr Adv Mat, Ben Guerir, Morocco..
    Valvo, Mario
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Passivation Layer and Cathodic Redox Reactions in Sodium-Ion Batteries Probed by HAXPES2016In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, no 1, p. 97-108Article in journal (Refereed)
    Abstract [en]

    The cathode material P2-NaxCo2/3Mn2/9Ni1/9O2, which could be used in Na-ion batteries, was investigated through synchrotron-based hard X-ray photoelectron spectroscopy (HAXPES). Nondestructive analysis was made through the electrode/electrolyte interface of the first electrochemical cycle to ensure access to information not only on the active material, but also on the passivation layer formed at the electrode surface and referred to as the solid permeable interface (SPI). This investigation clearly shows the role of the SPI and the complexity of the redox reactions. Cobalt, nickel, and manganese are all electrochemically active upon cycling between 4.5 and 2.0V; all are in the 4+ state at the end of charging. Reduction to Co3+, Ni3+, and Mn3+ occurs upon discharging and, at low potential, there is partial reversible reduction to Co2+ and Ni2+. A thin layer of Na2CO3 and NaF covers the pristine electrode and reversible dissolution/reformation of these compounds is observed during the first cycle. The salt degradation products in the SPI show a dependence on potential. Phosphates mainly form at the end of the charging cycle (4.5V), whereas fluorophosphates are produced at the end of discharging (2.0V).

  • 4.
    Ferdowsi, Parnian
    et al.
    Univ Guilan, Fac Engn, Dept Text Engn, Rasht 416353756, Iran.;Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photomol Sci, Dept Chem, CH-1015 Lausanne, Switzerland..
    Saygili, Yasemin
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photomol Sci, Dept Chem, CH-1015 Lausanne, Switzerland..
    Zhang, Weiwei
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photon & Interfaces, Dept Chem, CH-1015 Lausanne, Switzerland..
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Kavan, Ladislav
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photon & Interfaces, Dept Chem, CH-1015 Lausanne, Switzerland.;J Heyrovsky Inst Phys Chem, Prague 1823, Czech Republic..
    Mokhtari, Javad
    Univ Guilan, Fac Engn, Dept Text Engn, Rasht 416353756, Iran..
    Zakeeruddin, Shaik M.
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photon & Interfaces, Dept Chem, CH-1015 Lausanne, Switzerland..
    Grätzel, Michael
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photon & Interfaces, Dept Chem, CH-1015 Lausanne, Switzerland..
    Hagfeldt, Anders
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photomol Sci, Dept Chem, CH-1015 Lausanne, Switzerland..
    Molecular Design of Efficient Organic D-A-pi-A Dye Featuring Triphenylamine as Donor Fragment for Application in Dye-Sensitized Solar Cells2018In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 11, no 2, p. 494-502Article in journal (Refereed)
    Abstract [en]

    A metal-free organic sensitizer, suitable for the application in dye-sensitized solar cells (DSSCs), has been designed, synthesized and characterized both experimentally and theoretically. The structure of the novel donor-acceptor--bridge-acceptor (D-A-pi-A) dye incorporates a triphenylamine (TPA) segment and 4-(benzo[c][1,2,5]thiadiazol-4-ylethynyl)benzoic acid (BTEBA). The triphenylamine unit is widely used as an electron donor for photosensitizers, owing to its nonplanar molecular configuration and excellent electron-donating capability, whereas 4-(benzo[c][1,2,5]thiadiazol-4-ylethynyl)benzoic acid is used as an electron acceptor unit. The influences of I-3(-)/I-, [Co(bpy)(3)](3+/2+) and [Cu(tmby)(2)](2+/+) (tmby=4,4,6,6-tetramethyl-2,2-bipyridine) as redox electrolytes on the DSSC device performance were also investigated. The maximal monochromatic incident photon-to-current conversion efficiency (IPCE) reached 81% and the solar light to electrical energy conversion efficiency of devices with [Cu(tmby)(2)](2+/+) reached 7.15%. The devices with [Co(bpy)(3)](3+/2+) and I-3(-)/I- electrolytes gave efficiencies of 5.22% and 6.14%, respectively. The lowest device performance with a [Co(bpy)(3)](3+/2+)-based electrolyte is attributed to increased charge recombination.

  • 5.
    Galkin, Maxim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Samec, Joseph
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Selective Route to 2-Propenyl Aryls Directly from Wood by a Tandem Organosolv and Palladium-Catalysed Transfer Hydrogenolysis2014In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 8, p. 2154-2158Article in journal (Refereed)
    Abstract [en]

    A tandem organosolv pulping and Pd-catalysed transfer hydrogenolysis depolymerisation and deoxygenation has been developed. The tandem process generated 2-methoxy-4-(prop-1-enyl)phenol in 23 % yield (92 % theoretical monomer yield) starting from pine wood and 2,6-dimethoxy-4-(prop-1-enyl)phenol in 49 % yield (92 % theoretical monomer yield) starting from birch wood. Only endogenous hydrogen from wood was consumed, and the reaction was performed using green solvents.

  • 6.
    Galkin, Maxim V.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Dahlstrand, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Samec, Joseph S. M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Mild and Robust Redox-Neutral Pd/C-Catalyzed Lignol -O-4 Bond Cleavage Through a Low-Energy-Barrier Pathway2015In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, no 13, p. 2187-2192Article in journal (Refereed)
    Abstract [en]

    A Pd/C catalyzed redox neutral CO bond cleavage of 2-aryloxy-1-arylethanols has been developed. The reactions are carried out at 80 degrees C, in air, using a green solvent system to yield the aryl ketones in near quantitative yields. Addition of catalytic amounts of a hydrogen source to the reaction mixture activates the catalyst to proceed through a low energy barrier pathway. Initial studies support a transfer hydrogenolysis reaction mechanism that proceeds through an initial dehydrogenation followed by an enol adsorption to Pd/C and a reductive CO bond cleavage.

  • 7.
    Galkin, Maxim V.
    et al.
    Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Smit, Arjan T.
    Energy Res Ctr Netherlands ECN, Biomass & Energy Efficiency, Westerduinweg 3, NL-1755 LE Petten, Netherlands..
    Subbotina, Elena
    Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Artemenko, Konstantin A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Huijgen, Wouter J. J.
    Energy Res Ctr Netherlands ECN, Biomass & Energy Efficiency, Westerduinweg 3, NL-1755 LE Petten, Netherlands..
    Samec, Joseph S. M.
    Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Hydrogen-free catalytic fractionation of woody biomass2016In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, no 23, p. 3280-3287Article in journal (Refereed)
    Abstract [en]

    The pulping industry could become a biorefinery if the lignin and hemicellulose components of the lignocellulose are valorized. Conversion of lignin into well-defined aromatic chemicals is still a major challenge. Lignin depolymerization reactions often occur in parallel with irreversible condensation reactions of the formed fragments. Here, we describe a strategy that markedly suppresses the undesired condensation pathways and allows to selectively transform lignin into a few aromatic compounds. Notably, applying this strategy to woody biomass at organosolv pulping conditions, the hemicellulose, cellulose, and lignin were separated and in parallel the lignin was transformed into aromatic monomers. In addition, we were able to utilize a part of the lignocellulose as an internal source of hydrogen for the reductive lignin transformations. We hope that the presented methodology will inspire researchers in the field of lignin valorization as well as pulp producers to develop more efficient biomass fractionation processes in the future.

  • 8.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nicholas, James
    Univ South Australia, Future Ind Inst, Thin Film Coatings Grp, Adelaide, SA 5001, Australia.; Univ Bath, Dept Chem, Bath BA2 7AY, Avon, England.
    Evans, Drew
    Univ South Australia, Future Ind Inst, Thin Film Coatings Grp, Adelaide, SA 5001, Australia.
    Forsyth, Maria
    Deakin Univ, ARC Ctr Excellence Electromat Sci, Burwood 3125, Australia.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Howlett, Patrick C
    Deakin Univ, ARC Ctr Excellence Electromat Sci, Burwood 3125, Australia.
    Pozo-Gonzalo, Cristina
    Deakin Univ, ARC Ctr Excellence Electromat Sci, Burwood 3125, Australia.
    Stable Deep Doping of Vapor-Phase Polymerized Poly(3,4-ethylenedioxythiophene)/Ionic Liquid Supercapacitors.2016In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, no 16, p. 2112-2121Article in journal (Refereed)
    Abstract [en]

    Liquid-solution polymerization and vapor-phase polymerization (VPP) have been used to manufacture a series of chloride- and tosylate-doped poly(3,4-ethylenedioxythiophene) (PEDOT) carbon paper electrodes. The electrochemistry, specific capacitance, and specific charge were determined for single electrodes in 1-ethyl-3-methylimidazolium dicyanamide (emim dca) ionic liquid electrolyte. VPP-PEDOT exhibits outstanding properties with a specific capacitance higher than 300 F g(-1) , the highest value reported for a PEDOT-based conducting polymer, and doping levels as high as 0.7 charges per monomer were achieved. Furthermore, symmetric PEDOT supercapacitor cells with the emim dca electrolyte exhibited a high specific capacitance (76.4 F g(-1) ) and high specific energy (19.8 Wh kg(-1) ). A Ragone plot shows that the VPP-PEDOT cells combine the high specific power of conventional ("pure") capacitors with the high specific energy of batteries, a highly sought-after target for energy storage.

  • 9.
    Kwong, Wai Ling
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics. Umeå University, Umeå, Sweden.
    Gracia-Espino, Eduardo
    Umeå University, Umeå, Sweden.
    Lee, Cheng Choo
    Umeå University, Umeå, Sweden.
    Sandström, Robin
    Umeå University, Umeå, Sweden.
    Wågberg, Thomas
    Umeå University, Umeå, Sweden.
    Messinger, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics. Umeå University, Umeå, Sweden.
    Cationic Vacancy Defects in Iron Phosphide: A Promising Route toward Efficient and Stable Hydrogen Evolution by Electrochemical Water Splitting2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 22, p. 4544-4551Article in journal (Refereed)
    Abstract [en]

    Engineering the electronic properties of transition metal phosphides has shown great effectiveness in improving their intrinsic catalytic activity for the hydrogen evolution reaction (HER) in water splitting applications. Herein, we report for the first time, the creation of Fe vacancies as an approach to modulate the electronic structure of iron phosphide (FeP). The Fe vacancies were produced by chemical leaching of Mg that was introduced into FeP as "sacrificial dopant". The obtained Fevacancy-rich FeP nanoparticulate films, which were deposited on Ti foil, show excellent HER activity compared to pristine FeP and Mg-doped FeP, achieving a current density of 10 mA cm-2 at overpotentials of 108 mV in 1 m KOH and 65 mV in 0.5 m H2 SO4 , with a near-100 % Faradaic efficiency. Our theoretical and experimental analyses reveal that the improved HER activity originates from the presence of Fe vacancies, which lead to a synergistic modulation of the structural and electronic properties that result in a near-optimal hydrogen adsorption free energy and enhanced proton trapping. The success in catalytic improvement through the introduction of cationic vacancy defects has not only demonstrated the potential of Fe-vacancy-rich FeP as highly efficient, earth abundant HER catalyst, but also opens up an exciting pathway for activating other promising catalysts for electrochemical water splitting.

  • 10.
    Lacey, Matthew
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Österlund, Viking
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Bergfelt, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Jeschull, Fabian
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Bowden, Tim
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    A Robust, Water-Based, Functional Binder Framework for High-Energy Lithium-Sulfur Batteries2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 13, p. 2758-2766Article in journal (Refereed)
    Abstract [en]

    We report here a water-based functional binder framework for the lithium-sulfur battery systems, based on the general combination of a polyether and an amide-containing polymer. These binders are applied to positive electrodes optimised towards high-energy electrochemical performance based only on commercially available materials. Electrodes with up to 4 mAhcm(-2) capacity and 97-98% coulombic efficiency are achievable in electrodes with a 65% total sulfur content and a poly(ethylene oxide): poly(vinylpyrrolidone) (PEO: PVP) binder system. Exchange of either binder component for a different polymer with similar functionality preserves the high capacity and coulombic efficiency. The improvement in coulombic efficiency from the inclusion of the coordinating amide group was also observed in electrodes where pyrrolidone moieties were covalently grafted to the carbon black, indicating the role of this functionality in facilitating polysulfide adsorption to the electrode surface. The mechanical properties of the electrodes appear not to significantly influence sulfur utilisation or coulombic efficiency in the short term but rather determine retention of these properties over extended cycling. These results demonstrate the robustness of this very straightforward approach, as well as the considerable scope for designing binder materials with targeted properties.

  • 11.
    Lai, Qiwen
    et al.
    Univ New S Wales, Sch Chem Engn, MERLin Grp, Sydney, NSW 2052, Australia..
    Paskevicius, Mark
    Aarhus Univ, Dept Chem, DK-8000 Aarhus, Denmark.;Aarhus Univ, iNANO, DK-8000 Aarhus, Denmark.;Curtin Univ, Dept Phys Astron & Med Radiat Sci, Bentley, WA 6102, Australia..
    Sheppard, Drew A.
    Curtin Univ, Dept Phys Astron & Med Radiat Sci, Bentley, WA 6102, Australia..
    Buckley, Craig E.
    Curtin Univ, Dept Phys Astron & Med Radiat Sci, Bentley, WA 6102, Australia..
    Thornton, Aaron W.
    CSIRO, Clayton, Vic 3169, Australia..
    Hill, Matthew R.
    CSIRO, Clayton, Vic 3169, Australia..
    Gu, Qinfen
    Australian Synchrotron, Clayton, Vic 3168, Australia..
    Mao, Jianfeng
    Univ Wollongong, Inst Superconducting & Elect Mat, Wollongong, NSW 2500, Australia..
    Huang, Zhenguo
    Univ Wollongong, Inst Superconducting & Elect Mat, Wollongong, NSW 2500, Australia..
    Liu, Hua Kun
    Univ Wollongong, Inst Superconducting & Elect Mat, Wollongong, NSW 2500, Australia..
    Guo, Zaiping
    Univ Wollongong, Inst Superconducting & Elect Mat, Wollongong, NSW 2500, Australia..
    Banerjee, Amitava
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Chakraborty, Sudip
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Ahuja, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Aguey-Zinsou, Kondo-Francois
    Univ New S Wales, Sch Chem Engn, MERLin Grp, Sydney, NSW 2052, Australia..
    Hydrogen Storage Materials for Mobile and Stationary Applications: Current State of the Art2015In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, no 17, p. 2789-2825Article in journal (Refereed)
    Abstract [en]

    One of the limitations to the widespread use of hydrogen as an energy carrier is its storage in a safe and compact form. Herein, recent developments in effective high-capacity hydrogen storage materials are reviewed, with a special emphasis on light compounds, including those based on organic porous structures, boron, nitrogen, and aluminum. These elements and their related compounds hold the promise of high, reversible, and practical hydrogen storage capacity for mobile applications, including vehicles and portable power equipment, but also for the large scale and distributed storage of energy for stationary applications. Current understanding of the fundamental principles that govern the interaction of hydrogen with these light compounds is summarized, as well as basic strategies to meet practical targets of hydrogen uptake and release. The limitation of these strategies and current understanding is also discussed and new directions proposed.

  • 12. Li, Hairong
    et al.
    Fu, Kunwu
    Boix, Pablo P.
    Wong, Lydia H.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Graetzel, Michael
    Mhaisalkar, Subodh G.
    Grimsdale, Andrew C.
    Hole-Transporting Small Molecules Based on Thiophene Cores for High Efficiency Perovskite Solar Cells2014In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 12, p. 3420-3425Article in journal (Refereed)
    Abstract [en]

    Two new electron-rich molecules, 2,3,4,5-tetra[4,4'-bis(methoxyphenyl)aminophen-4 ''-yl]-thiophene (H111) and 4,4',5,5'-tetra[4,4'-bis(methoxyphenyl) aminophen-4 ''-yl]-2,2'-bithiophene (H112), which contain thiophene cores with arylamine side groups, are reported. When used as the hole-transporting material (HTM) in perovskite-based solar cell devices, power conversion efficiencies of up to 15.4% under AM 1.5G solar simulation were obtained. This is the highest efficiency achieved with HTMs not composed of 2,2',7,7'-tetrakis(N,N'-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD) and its isomers. Both HTMs, especially H111, have great potential to replace expensive spiro-OMeTAD given their much simpler and less expensive syntheses.

  • 13.
    Li, Hairong
    et al.
    Nanyang Technol Univ, Energy Res Inst NTU ERI N, Sch Mat Sci & Engn, Singapore 637553, Singapore.
    Koh, Teck Ming
    Nanyang Technol Univ, Energy Res Inst NTU ERI N, Sch Mat Sci & Engn, Singapore 637553, Singapore.
    Hao, Yan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Zhou, Feng
    Nanyang Technol Univ, Energy Res Inst NTU ERI N, Sch Mat Sci & Engn, Singapore 637553, Singapore.
    Abe, Yuichiro
    Nanyang Technol Univ, Energy Res Inst NTU ERI N, Sch Mat Sci & Engn, Singapore 637553, Singapore.
    Su, Haibin
    Nanyang Technol Univ, Energy Res Inst NTU ERI N, Sch Mat Sci & Engn, Singapore 637553, Singapore.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Grimsdale, Andrew C.
    Nanyang Technol Univ, Energy Res Inst NTU ERI N, Sch Mat Sci & Engn, Singapore 637553, Singapore.
    Comparative Studies on Rigid pi Linker-Based Organic Dyes: Structure-Property Relationships and Photovoltaic Performance2014In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 12, p. 3396-3406Article in journal (Refereed)
    Abstract [en]

    A series of six structurally correlated donor-pi bridge-acceptor organic dyes were designed, synthesized, and applied as sensitizers in dye-sensitized solar cells. Using the most widely studied donor (triarylamine) and cyclopenta[1,2-b:5,4-b’]dithiophene or cyclopenta[1,2-b: 5,4-b’] dithiophene[2’,1’:4,5]thieno[2,3-d] thiophene as pi spacers, their structure-property relationships were investigated in depth by photophysical techniques and theoretical calculations. It was found that the photovoltaic performance of these dyes largely depends on their electronic structures, which requires synergistic interaction between donors and acceptors. Increasing the electron richness of the donor or the elongation of pi-conjugated bridges does not necessarily lead to higher performance. Rather, it is essential to rationally design the dyes by balancing their light-harvesting capability with achieving suitable energy levels to guarantee unimpeded charge separation and transport.

  • 14. Li, Ling
    et al.
    Hao, Yan
    Yang, Xichuan
    Zhao, Jianzhang
    Tian, Haining
    Teng, Chao
    Hagfeldt, Anders
    Sun, Licheng.
    A Double-Band Tandem Organic Dye-sensitized Solar Cell with an Efficiency of 11.5 %.2011In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 4, no 5, p. 609-612Article in journal (Refereed)
    Abstract [en]

    The absorption spectra of most org. dyes reported thus far used for mesoporous nanostructured dye-sensitized solar cells mainly cover the visible-light region. This has motivated research towards the development of new types of org. dyes(7-10) with absorption spectra extended to the near-IR and IR region. By adjusting the donor, linker, and acceptor units, this group developed a tandem Dye-sensitized Solar Cell in which the front subcell employs a ZrO2-doped nanostructured TiO2 semiconductor to improve the photovoltage and an org. 3-[2-(N,N-diphenylamino)-ethenyl]-phenoxazinyl-cyanoacrylic acid dye (TH305) to harvest sunlight in the 400-750 nm region, giving an efficiency of 9.05 % with a high photovoltage (794 mV), while the back subcell employs a normal TiO2 electrode sensitized with a different org. dye (HY103) to capture sunlight in the 500-800 nm region, achieving an addnl. efficiency of 2.45 %. The two sub-cells are sepd. by a double-sided fluoride-doped tin oxide conducting glass. Shifting the CB band of TiO2towards more neg. values is an effective way to improve the open-circuit photovoltage (Voc) and increase the DSC's efficiency. The two methods used to make the CB more neg. are : (a) adding an org. base, 4-tert-butylpyridine, to the electrolyte, and (b) doping the TiO2 with semiconductor materials with a more-neg. CB energy level (EcB), ZrO2, which has a wider band gap (ca. 5.0 eV) and a more-neg. CB level (-1.0 V vs. normal hydrogen electrode). The org. dye TH305 was chosen for the front subcell because its more neg. LUMO level (-1.28V vs. NHE) matches the ECB of ZrO2-doped TiO2. Undoped titania was used for the second sub-cell. The total conversion efficiency was 9.05%, with a Voc of 0.794V, and a Jsc of 15/20 mA/cm2. [on SciFinder(R)]

  • 15.
    Liu, Chenjuan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Brant, William
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Younesi, Reza
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Dong, Yanyan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Beijing Forestry Univ, Coll Mat Sci & Technol, Beijing Key Lab Lignocellulos Chem, Beijing 100083, Peoples R China..
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Zhu, Jiefang
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Dalian Univ Technol, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Towards an Understanding of Li2O2 Evolution in Li-O2 Batteries: An In-operando Synchrotron X-ray Diffraction Study2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 7, p. 1592-1599Article in journal (Refereed)
    Abstract [en]

    One of the major challenges in developing high-performance Li-O-2 batteries is to understand the Li2O2 formation and decomposition during battery cycling. In this study, this issue was investigated by synchrotron radiation powder X-ray diffraction. The evolution of Li2O2 morphology and structure was observed under actual electrochemical conditions of battery operation. By quantitatively tracking Li2O2 during discharge and charge, a two-step process was suggested for both growth and oxidation of Li2O2 owing to different mechanisms during two stages of both oxygen reduction reaction and oxygen evolution reaction. From an observation of the anisotropic broadening of Li2O2 in XRD patterns, it was inferred that disc-like Li2O2 grains are formed rapidly in the first step of discharge. These grains can stack together so that they facilitate the nucleation and growth of toroidal Li2O2 particles with a LiO2-like surface, which could cause parasitic reactions and hinder the formation of Li2O2. During the charge process, Li2O2 is firstly oxidized from the surface, followed by a delithiation process with a faster oxidation of the bulk by stripping the interlayer Li atoms to form an off-stoichiometric intermediate. This fundamental insight brings new information on the working mechanism of Li-O-2 batteries.

  • 16.
    Liu, Jia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Renault, Steven
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Zhu, Jiefang
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    An Organic Catalyst for Li-O-2 Batteries: Dilithium Quinone-1,4-Dicarboxylate2015In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, no 13, p. 2198-2203Article in journal (Refereed)
    Abstract [en]

    Solid organic electrocatalysts have hardly been tested in Li-O-2 batteries. Here, a new solid organic electrocatalyst, dilithium quinone-1,4-dicarboxylate (Li2C8H2O6) is presented, which is expected to overcome the shortcomings of inorganic catalysts. The function-oriented synthesis is low cost and low polluting. The electrocatalytic performance is evaluated by following the degradation of Li2O2 during the charge process in a Li-O-2 cell through insitu XRD and operando synchrotron radiation powder XRD (SR-PXD) measurements. The results indicate that the electrocatalytic activity of Li2C8H2O6 is similar to that of commercial Pt. The Li2O2 decomposition in a cell with Li2C8H2O6 catalyst follows a pseudo-zero-order reaction, virtually without any side reactions. These results provide an insight into the development of new organic catalysts for the oxygen evolution reaction (OER) in Li-O-2 batteries.

  • 17.
    Lofstedt, Joakim
    et al.
    Renfuel AB, Sturegatan 38, S-11436 Stockholm, Sweden..
    Dahlstrand, Christian
    Renfuel AB, Sturegatan 38, S-11436 Stockholm, Sweden..
    Orebom, Alexander
    Renfuel AB, Sturegatan 38, S-11436 Stockholm, Sweden..
    Meuzelaar, Gerrit
    Renfuel AB, Sturegatan 38, S-11436 Stockholm, Sweden..
    Sawadjoon, Supaporn
    Renfuel AB, Sturegatan 38, S-11436 Stockholm, Sweden..
    Galkin, Maxim V.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Agback, Peter
    Swedish Univ Agr Sci, Dept Chem, Uppsala BioCtr, POB 7015, S-75007 Uppsala, Sweden..
    Wimby, Martin
    Valmet AB, Regnbagsgatan 6, S-41755 Gothenburg, Sweden..
    Corresa, Elena
    Univ Politecn Valencia, Inst Tecnol Quim UPV CSIC, Ave Tarongers S-N, E-46022 Valencia, Spain..
    Mathieu, Yannick
    Univ Politecn Valencia, Inst Tecnol Quim UPV CSIC, Ave Tarongers S-N, E-46022 Valencia, Spain..
    Sauvanaud, Laurent
    Univ Politecn Valencia, Inst Tecnol Quim UPV CSIC, Ave Tarongers S-N, E-46022 Valencia, Spain..
    Eriksson, Sören
    Preem AB, Warfvinges Vag 45, S-11251 Stockholm, Sweden..
    Corma, Avelino
    Univ Politecn Valencia, Inst Tecnol Quim UPV CSIC, Ave Tarongers S-N, E-46022 Valencia, Spain..
    Samec, Joseph S. M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC. Renfuel AB, Sturegatan 38, S-11436 Stockholm, Sweden..
    Green Diesel from Kraft Lignin in Three Steps2016In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, no 12, p. 1392-1396Article in journal (Refereed)
    Abstract [en]

    Precipitated kraft lignin from black liquor was converted into green diesel in three steps. A mild Ni-catalyzed transfer hydrogenation/hydrogenolysis using 2-propanol generated a lignin residue in which the ethers, carbonyls, and olefins were reduced. An organocatalyzed esterification of the lignin residue with an insitu prepared tall oil fatty acid anhydride gave an esterified lignin residue that was soluble in light gas oil. The esterified lignin residue was coprocessed with light gas oil in a continous hydrotreater to produce a green diesel. This approach will enable the development of new techniques to process commercial lignin in existing oil refinery infrastructures to standardized transportation fuels in the future.

  • 18.
    Loos, Stefan
    et al.
    Free Univ Berlin, Inst Expt Phys, Arnimallee 14, D-014195 Berlin, Germany;Fraunhofer Inst Mfg Technol & Adv Mat IFAM, Winterbergstr 28, D-01277 Dresden, Germany.
    Zaharieva, Ivelina
    Free Univ Berlin, Inst Expt Phys, Arnimallee 14, D-014195 Berlin, Germany.
    Chernev, Petko
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics. Free Univ Berlin, Inst Expt Phys, Arnimallee 14, D-014195 Berlin, Germany.
    Lissner, Andreas
    Tech Univ Bergakad Freiberg, Inst Phys Chem, Leipziger Str 29, D-09599 Freiberg, Germany.
    Dau, Holger
    Free Univ Berlin, Inst Expt Phys, Arnimallee 14, D-014195 Berlin, Germany.
    Electromodified NiFe Alloys as Electrocatalysts for Water Oxidation: Mechanistic Implications of Time-Resolved UV/Vis Tracking of Oxidation State Changes2019In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 12, no 9, p. 1966-1976Article in journal (Refereed)
    Abstract [en]

    Facile electromodification of metallic NiFe alloys leads to a series of NiFe oxyhydroxide surface films with excellent electrocatalytic performance in alkaline water oxidation. During cyclic voltammetry and after sudden potential jumps between noncatalytic and catalytic potentials, Ni oxidation/reduction was tracked with millisecond time resolution by a UV/Vis reflectance signal. Optimal catalysis at intermediate Ni/Fe ratios is explained by two opposing trends for increasing Fe content: a)pronounced slowdown of the Ni2+/Ni3+ oxidation step and b)increased reactivity of the most oxidized catalyst state detectable at catalytic potentials. This state may involve an equilibrium between Ni4+ ions and Ni2+ ions with neighboring ligand holes, possibly in the form of bound peroxides.

  • 19.
    Ma, Yue
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Tai, Cheuk-Wai
    Stockholm University.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Recycled Poly(vinyl alcohol) Sponge for Carbon Encapsulation of Size-Tunable Tin Dioxide Nanocrystalline Composites2015In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, no 12, p. 2084-2092Article in journal (Refereed)
    Abstract [en]

    The recycling of industrial materials could reduce their environmental impact and waste haulage fees and result in sustainable manufacturing. In this work, commercial poly(vinyl alcohol) (PVA) sponges are recycled into a macroporous carbon matrix to encapsulate size-tunable SnO2 nanocrystals as anode materials for lithium-ion batteries (LIBs) through a scalable, flash-combustion method. The hydroxyl groups present copiously in the recycled PVA sponges guarantee a uniform chemical coupling with a tin(IV) citrate complex through intermolecular hydrogen bonds. Then, a scalable, ultrafast combustion process (30s) carbonizes the PVA sponge into a 3D carbon matrix. This PVA-sponge-derived carbon could not only buffer the volume fluctuations upon the Li-Sn alloying and dealloying processes but also afford a mixed conductive network, that is, a continuous carbon framework for electrical transport and macropores for facile electrolyte percolation. The best-performing electrode based on this composite delivers a rate performance up to 9.72C (4Ag(-1)) and long-term cyclability (500cycles) for Li+ ion storage. Moreover, cyclic voltammograms demonstrate the coexistence of alloying and dealloying processes and non-diffusion-controlled pseudocapacitive behavior, which collectively contribute to the high-rate Li+ ion storage.

  • 20.
    Mahanti, Bani
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    González Miera, Greco
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm, Sweden.
    Martínez-Castro, Elisa
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm, Sweden.
    Bedin, Michele
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Martín-Matute, Belen
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm, Sweden.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Thapper, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Homogeneous Water Oxidation by Half-Sandwich Iridium(III) N-Heterocyclic Carbene Complexes with Pendant Hydroxy and Amino Groups2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 22, p. 4616-4623Article in journal (Refereed)
    Abstract [en]

    Herein, we report three IrIIICp* complexes with hydroxy- or amino-functionalized N-heterocyclic carbene (NHC) ligands that catalyze efficient water oxidation induced by addition of ceric ammonium nitrate (CAN). The pendant hydroxy or amino groups are very important for activity, and the complexes with heteroatom-functionalized NHC ligands show up to 15 times higher rates of oxygen evolution in CAN-induced water oxidation than a reference IrIIICp* complex without heteroatom functionalization. The formation of molecular high-valent Ir intermediates that are presumably involved in the rate-determining step for water oxidation is established by UV/Vis spectroscopy and ESI-MS under turnover conditions. The hydroxy groups on the NHC ligands, as well as chloride ligands on the iridium center are proposed to structurally stabilize the high-valent species, and thereby improve the catalytic activity. The IrIII complex with a hydroxy-functionalized NHC shows the highest catalytic activity with a TON of 2500 obtained in 3 h and with ~90 % yield relative to the amount of oxidant used.

  • 21.
    Melder, Jens
    et al.
    Albert-Ludwigs-Universitat, Freiburg, Germany.
    Kwong, Wai Ling
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics. Umeå Universitet, Umeå, Sweden.
    Shevela, Dmitriy
    Umeå Universitet, Umeå, Sweden.
    Messinger, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics. Umeå Universitet, Umeå, Sweden.
    Kurz, Philipp
    Albert-Ludwigs-Universitat Freiburg, Germany.
    Electrocatalytic Water Oxidation by MnOx /C: In Situ Catalyst Formation, Carbon Substrate Variations, and Direct O2 /CO2 Monitoring by Membrane-Inlet Mass Spectrometry2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 22, p. 4491-4502Article in journal (Refereed)
    Abstract [en]

    Layers of amorphous manganese oxides were directly formed on the surfaces of different carbon materials by exposing the carbon to aqueous solutions of permanganate (MnO4- ) followed by sintering at 100-400 °C. During electrochemical measurements in neutral aqueous buffer, nearly all of the MnOx /C electrodes show significant oxidation currents at potentials relevant for the oxygen evolution reaction (OER). However, by combining electrolysis with product detection by using mass spectrometry, it was found that these currents were only strictly linked to water oxidation if MnOx was deposited on graphitic carbon materials (faradaic O2 yields >90 %). On the contrary, supports containing sp3 -C were found to be unsuitable as the OER is accompanied by carbon corrosion to CO2 . Thus, choosing the "right" carbon material is crucial for the preparation of stable and efficient MnOx /C anodes for water oxidation catalysis. For MnOx on graphitic substrates, current densities of >1 mA cm-2 at η=540 mV could be maintained for at least 16 h of continuous operation at pH 7 (very good values for electrodes containing only abundant elements such as C, O, and Mn) and post-operando measurements proved the integrity of both the catalyst coating and the underlying carbon at OER conditions.

  • 22. Ning, Zhijun
    et al.
    Yuan, Chunze
    Tian, Haining
    Hedstroem, Peter
    Sun, Licheng
    Aagren, Hans.
    Quantum Rod-Sensitized Solar Cells.2011In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 4, no 12, p. 1741-1744Article in journal (Refereed)
    Abstract [en]

    A new type of CdSe nanorod material was prepd. with cadmium sulfide as seed material and the properties of a quantum rod-sensitized titania solar cell were studied. This cell showed better electron injection efficiency than corresponding quantum dot-sensitized solar cells, indicating that electrons can be more easily injected from quantum rods than from quantum dots. We have demonstrated a new strategy to increase the electron injection efficiency of nanocrystal-sensitized solar cells by modification of the shape of the nanocrystals. [on SciFinder(R)]

  • 23.
    Pati, Palas Baran
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Zhang, Lei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Philippe, Bertrand
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Fernández-Terán, Ricardo
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ahmadi, Sareh
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Tian, Lei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Insights into the Mechanism of a Covalently Linked Organic Dye-Cobaloxime Catalyst System for Dye-Sensitized Solar Fuel Devices2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 11, p. 2480-2495Article in journal (Refereed)
    Abstract [en]

    A covalently-linked organic dye-cobaloxime catalyst system is developed by facile click reaction for mechanistic studies and application in a dye sensitized solar fuel device based on mesoporous NiO. This system has been systematically investigated by photophysical measurements, density functional theory, time resolved fluorescence, transient absorption spectroscopy as well as photoelectron spectroscopy. The results show that irradiation of the dye-catalyst on NiO leads to ultrafast hole injection into NiO from the excited dye, followed by a fast electron transfer to reduce the catalyst unit. Moreover, they suggest that the dye undergoes structural changes in the excited state and that excitation energy transfer occurs between neighboring molecules. The photoelectrochemical experiments also show the hydrogen production by this system-based NiO photocathode. The axial chloride ligands of the catalyst are released during photocatalysis to create the active sites for proton reduction. A working mechanism of the dye-catalyst on photocathode is eventually proposed on the basis of this study.

  • 24.
    Pavliuk, Mariia V.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. Taras Shevchenko Natl Univ Kyiv, Dept Inorgan Chem, Volodymyrska St 64-13, UA-01601 Kiev, Ukraine.
    Mijangos, Edgar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Makhankova, Valeriya G.
    Taras Shevchenko Natl Univ Kyiv, Dept Inorgan Chem, Volodymyrska St 64-13, UA-01601 Kiev, Ukraine.
    Kokozay, Vladimir N.
    Taras Shevchenko Natl Univ Kyiv, Dept Inorgan Chem, Volodymyrska St 64-13, UA-01601 Kiev, Ukraine.
    Pullen, Sonja
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Liu, Jia
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Zhu, Jie-Fang
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Thapper, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Homogeneous Cobalt/Vanadium Complexes as Precursors for Functionalized Mixed Oxides in Visible-Light-Driven Water Oxidation2016In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, no 20, p. 2957-2966Article in journal (Refereed)
    Abstract [en]

    The heterometallic complexes (NH4)2[Co(H2O)6]2[V10O28]·4H2O (1) and (NH4)2[Co(H2O)5(β-HAla)]2[V10O28]·4H2O (2) have been synthesized and used for the preparation of mixed oxides as catalysts for water oxidation. Thermal decomposition of 1 and 2 at relatively low temperatures (<500 °C) leads to the formation of the solid mixed oxides CoV2O6/V2O5 (3) and Co2V2O7/V2O5 (4). The complexes (1, 2) and heterogeneous materials (3, 4) act as catalysts for photoinduced water oxidation. A modification of the thermal decomposition procedure allowed the deposition of mixed metal oxides (MMO) on a mesoporous TiO2 film. The electrodes containing Co/V MMOs in TiO2 films were used for electrocatalytic water oxidation and showed good stability and sustained anodic currents of about 5 mA cm−2 at 1.72 V versus relative hydrogen electrode (RHE). This method of functionalizing TiO2 films with MMOs at relatively low temperatures (<500 °C) can be used to produce other oxides with different functionality for applications in, for example, artificial photosynthesis.

  • 25.
    Rautiainen, Sari
    et al.
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    Di Francesco, Davide
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    Katea, Sarmad Naim
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Westin, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Tungasmita, Duangamol N.
    Chulalongkorn Univ, Fac Sci, Dept Chem, Ctr Excellence Catalysis Bioenergy & Renewable Ch, Bangkok 10330, Thailand.
    Samec, Joseph S. M.
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    Lignin Valorization by Cobalt-Catalyzed Fractionation of Lignocellulose to Yield Monophenolic Compounds2019In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 12, no 2, p. 404-408Article in journal (Refereed)
    Abstract [en]

    Herein, a catalytic reductive fractionation of lignocellulose is presented using a heterogeneous cobalt catalyst and formic acid or formate as a hydrogen donor. The catalytic reductive fractionation of untreated birch wood yields monophenolic compounds in up to 34 wt % yield of total lignin, which corresponds to 76% of the theoretical maximum yield. Model compound studies revealed that the main role of the cobalt catalyst is to stabilize the reactive intermediates formed during the organosolv pulping by transfer hydrogenation and hydrogenolysis reactions. Additionally, the cobalt catalyst is responsible for depolymerization reactions of lignin fragments through transfer hydrogenolysis reactions, which target the beta-O-4' bond. The catalyst could be recycled three times with only negligible decrease in efficiency, showing the robustness of the system.

  • 26.
    Renault, Stéven
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Environmentally-Friendly Lithium Recycling From a Spent Organic Li-Ion Battery2014In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 10, p. 2859-2867Article in journal (Refereed)
    Abstract [en]

    A simple and straightforward method using non-polluting solvents and a single thermal treatment step at moderate temperature was investigated as an environmentally-friendly process to recycle lithium from organic electrode materials for secondary lithium batteries. This method, highly dependent on the choice of electrolyte, gives up to 99% of sustained capacity for the recycled materials used in a second life-cycle battery when compared with the original. The best results were obtained using a dimethyl carbonate/lithium bis(trifluoromethane sulfonyl) imide electrolyte that does not decompose in presence of water. The process implies a thermal decomposition step at a moderate temperature of the extracted organic material into lithium carbonate, which is then used as a lithiation agent for the preparation of fresh electrode material without loss of lithium.

  • 27.
    Roy, Souvik
    et al.
    Univ Grenoble Alpes, CNRS, CEA, Lab Chem & Biol Met, F-38000 Grenoble, France..
    Bacchi, Marine
    Univ Grenoble Alpes, CNRS, CEA, Lab Chem & Biol Met, F-38000 Grenoble, France..
    Berggren, Gustav
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics. Univ Grenoble Alpes, CNRS, CEA, Lab Chem & Biol Met, F-38000 Grenoble, France..
    Artero, Vincent
    Univ Grenoble Alpes, CNRS, CEA, Lab Chem & Biol Met, F-38000 Grenoble, France..
    A Systematic Comparative Study of Hydrogen-Evolving Molecular Catalysts in Aqueous Solutions2015In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, no 21, p. 3632-3638Article in journal (Refereed)
    Abstract [en]

    We describe here a systematic, reliable, and fast screening method that allows the comparison of H-2-forming catalysts that work under aqueous conditions with two readily prepared chemical reductants and two commonly used photosensitizers. This method uses a Clark-type microsensor for H-2 detection and complements previous methods based on rotating disk electrode measurements. The efficiencies of a series of H-2-producing catalysts based on Co, Ni, Fe, and Pt were investigated in aqueous solutions under thermal conditions with europium(II) reductants and under photochemical conditions in the presence of two different photosensitizers {[Ru(bipy)(3)]Cl-2 (bipy=2,2-bipyridine) and eosin-Y} and sacrificial electron donors (ascorbate and triethanolamine, respectively). The majority of catalysts tested were active only under specific conditions. However, our results also demonstrate the impressive versatility of a group of Co catalysts, which were able to produce H-2 under different reducing conditions and at various pH values. In particular, a cobaloxime, [Co(dmgH)(2)(H2O)(2)] (dmgH(2)=dimethylglyoxime), and a cobalt tetraazamacrocyclic complex, {Co(CR)Cl-2}(+) [CR=2,12-dimethyl-3,7,11,17-tetraazabicylo(11.3.1)heptadeca-1(17),2,11,13,15-pentaene], displayed excellent catalytic rates under the studied conditions, and the best rates were observed under thermal conditions.

  • 28. Saygili, Yasemin
    et al.
    Turren-Cruz, Silver-Hamill
    Olthof, Selina
    Saes, Bartholomeus Wilhelmus Henricus
    Bayrak Pehlivan, Ilknur
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Saliba, Michael
    Meerholz, Klaus
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Zakeeruddin, Shaik M.
    Grätzel, Michael
    Correa-Baena, Juan-Pablo
    Hagfeldt, Anders
    Freitag, Marina
    Tress, Wolfgang
    Planar Perovskite Solar Cells with High Open-CircuitVoltage Containing a Supramolecular Iron Complex as HoleTransport Material Dopant2018In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 19, p. 1-9Article in journal (Refereed)
    Abstract [en]

    n perovskite solar cells (PSCs), the most commonly used hole transport material (HTM) is spiro-OMeTAD, which is typically doped by metalorganic complexes, for example, based on Co, to improve charge transport properties and thereby enhance the photovoltaic performance of the device. In this study, we report a new hemicage-structured iron complex, 1,3,5-tris(5'-methyl-2,2'-bipyridin-5-yl)ethylbenzene Fe(III)-tris(bis(trifluoromethylsulfonyl)imide), as a p-type dopant for spiro-OMeTAD. The formal redox potential of this compound was measured as 1.29 V vs. the standard hydrogen electrode, which is slightly (20 mV) more positive than that of the commercial cobalt dopant FK209. Photoelectron spectroscopy measurements confirm that the iron complex acts as an efficient p-dopant, as evidenced in an increase of the spiro-OMeTAD work function. When fabricating planar PSCs with the HTM spiro-OMeTAD doped by 5 mol % of the iron complex, a power conversion efficiency of 19.5 % (AM 1.5G, 100 mW cm-2 ) is achieved, compared to 19.3 % for reference devices with FK209. Open circuit voltages exceeding 1.2 V at 1 sun and reaching 1.27 V at 3 suns indicate that recombination at the perovskite/HTM interface is low when employing this iron complex. This work contributes to recent endeavors to reduce recombination losses in perovskite solar cells.

  • 29.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Molecular Catalyst Immobilized Photocathodes for Water/Proton and Carbon Dioxide Reduction2015In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, no 22, p. 3746-3759Article, review/survey (Refereed)
    Abstract [en]

    As one of the components in a tandem photoelectrochemical cell for solar-fuel production, the photocathode carries out the reduction reaction to convert solar light and the corresponding substrate (e.g., proton and CO2) into target fuels. Immobilizing molecular catalysts onto the photocathode is a promising strategy to enhance the interfacial electron/hole-transfer process and to improve the stability of the catalysts. Furthermore, the molecular catalysts are beneficial in improving the selectivity of the reduction reaction, particularly for CO2 reduction. On the photocathode, the binding mode of the catalysts and the arrangement between the photosensitizer and the catalyst also play crucial roles in the performance and stability of the final device. How to firmly and effectively immobilize the catalyst on the photoelectrode is now becoming a scientific question. Recent publications on molecular catalyst immobilized photocathodes are therefore surveyed.

  • 30. Tian, Haining
    Solid-State Perovskite-Sensitized p-Type Mesoporous Nickel Oxide Solar Cells2014In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 8, p. 2150-2153Article in journal (Refereed)
  • 31. Tian, Haining
    et al.
    Xu, Bo
    Chen, Hong
    Johansson, Erik M. J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Solid-State Perovskite-Sensitized p-Type Mesoporous Nickel Oxide Solar Cells2014In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 8, p. 2150-2153Article in journal (Refereed)
    Abstract [en]

    ,Perovskite has been adopted as photosensitizer to develop solid state p-type mesoporous nickel oxide (NiO) dye-sensitized solar cells (DSCs) employing PCBM as electron conductor. The optimal device achieved an efficiency of 1.5% with an impressive open circuit voltage of more than 800 mV, which is the record of solar cell based on p-type mesoporous NiO electrode. This result shows the potential for building highly efficient p-type NiO solar cells as stand-alone device.

  • 32.
    Valvo, Mario
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Liivat, Anti
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Eriksson, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Tai, Cheuk-Wai
    Stockholm Univ, Dept Mat & Environm Chem, Arrhenius Lab.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Iron-Based Electrodes Meet Water-Based Preparation, Fluorine-Free Electrolyte and Binder: A Chance for More Sustainable Lithium-Ion Batteries?2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 11, p. 2431-2448Article in journal (Refereed)
    Abstract [en]

    Environmentally friendly and cost-effective Li-ion cells are fabricated with abundant, non-toxic LiFePO4 cathodes and iron oxide anodes. A water-soluble alginate binder is used to coat both electrodes to reduce the environmental footprint. The critical reactivity of LiPF6-based electrolytes toward possible traces of H2O in water-processed electrodes is overcome by using a lithium bis(oxalato) borate (LiBOB) salt. The absence of fluorine in the electrolyte and binder is a cornerstone for improved cell chemistry and results in stable battery operation. A dedicated approach to exploit conversion-type anodes more effectively is also disclosed. The issue of large voltage hysteresis upon conversion/de-conversion is circumvented by operating iron oxide in a deeply lithiated Fe/Li2O form. Li-ion cells with energy efficiencies of up to 92% are demonstrated if LiFePO4 is cycled versus such anodes prepared through a prelithiation procedure. These cells show an average energy efficiency of approximately 90.66% and a mean Coulombic efficiency of approximately 99.65% over 320 cycles at current densities of 0.1, 0.2 and 0.3 mAcm(-2). They retain nearly 100% of their initial discharge capacity and provide an unmatched operation potential of approximately 2.85 V for this combination of active materials. No occurrence of Li plating was detected in three-electrode cells at charging rates of approximately 5C. Excellent rate capabilities of up to approximately 30C are achieved thanks to the exploitation of size effects from the small Fe nanoparticles and their reactive boundaries.

  • 33.
    Verendel, J. Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Nordlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Pher G.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Selective, metal-catalyzed transfer of H2 and CO from polyols to alkenes2013In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 6, no 3, p. 426-429Article in journal (Refereed)
  • 34. Xu, Bo
    et al.
    Huang, Jing
    Agren, Hans
    Kloo, Lars
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Sun, Licheng
    AgTFSI as p-Type Dopant for Efficient and Stable Solid-State Dye-Sensitized and Perovskite Solar Cells2014In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 12, p. 3252-3256Article in journal (Refereed)
    Abstract [en]

    A silver-based organic salt, silver bis(trifluoromethane-sulfonyl) imide (AgTFSI), was employed as an effective p-type dopant for the triarylamine-based organic hole-transport material Spiro-MeOTAD, which has been successfully applied in solid-state dye-sensitized solar cells (ssDSCs) and perovskite solar cells (PSCs). The power conversion efficiencies (PCEs) of AgTFSI-doped devices improved by 20%, as compared to the device based on the commonly used oxygen doping both for ssDSCs and PSCs. Moreover, the solid-state dye-sensitized devices exposed to AgTFSI as dopant showed considerably better stability than those of oxygen doped, qualifying this p-type dopant as a promising alterative for the preparation of highly efficient as well as stable ssDSCs and PSCs for the future.

  • 35. Yun, Sining
    et al.
    Pu, Haihui
    Chen, Junhong
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ma, Tingli
    Enhanced Performance of Supported HfO2 Counter Electrodes for Redox Couples Used in Dye-Sensitized Solar Cells2014In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 2, p. 442-450Article in journal (Refereed)
    Abstract [en]

    Mesoporous-graphitic-carbon-supported HfO2 (HfO2-MGC) nanohybrids were synthesized by using a soft-template route. Characterization and a systematic investigation of the catalytic properties, stability, and catalytic mechanism were performed for HfO2-MGC counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). The new HfO2-MGC as a CE in DSSCs showed a surprisingly high efficiency of 7.75% for the triiodide/iodide redox couple and 3.69% for the disulfide/thiolate redox couple, greater than the Pt electrode in the corresponding electrolyte system, which opens up a possibility for its practical application.

  • 36. Yun, Sining
    et al.
    Wu, Mingxing
    Wang, Yudi
    Shi, Jing
    Lin, Xiao
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ma, Tingli
    Pt-like Behavior of High-Performance Counter Electrodes Prepared from Binary Tantalum Compounds Showing High Electrocatalytic Activity for Dye-Sensitized Solar Cells2013In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 6, no 3, p. 411-416Article in journal (Refereed)
  • 37.
    Zhang, Biaobiao
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Li, Yuanyuan
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Valvo, Mario
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Fan, Lizhou
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Daniel, Quentin
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Zhang, Peili
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Wang, Linqin
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Sun, Licheng
    KTH Royal Institute of Technology, Stockholm, Sweden; Dalian University of Technology, Dalian, China.
    Electrocatalytic Water Oxidation Promoted by 3 D Nanoarchitectured Turbostratic δ-MnOx on Carbon Nanotubes2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 22, p. 4472-4478Article in journal (Refereed)
    Abstract [en]

    The development of manganese-based water oxidation electrocatalysts is desirable for the production of solar fuels, as manganese is earth-abundant, inexpensive, non-toxic, and has been employed by the Photosystem II in nature for a billion years. Herein, we directly constructed a 3 D nanoarchitectured turbostratic δ-MnOx on carbon nanotube-modified nickel foam (MnOx/CNT/NF) by electrodeposition and a subsequent annealing process. The MnOx/CNT/NF electrode gives a benchmark catalytic current density (10 mA cm−2) at an overpotential (η) of 270 mV under alkaline conditions. A steady current density of 19 mA cm−2 is obtained during electrolysis at 1.53 V for 1.0 h. To the best of our knowledge, this work represents the most efficient manganese-oxide-based water oxidation electrode and demonstrates that manganese oxides, as a structural and functional model of oxygen-evolving complex (OEC) in Photosystem II, can also become comparable to those of most Ni- and Co-based catalysts.

  • 38.
    Zhang, Jinbao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. Monash Univ, Dept Mat Engn, Clayton, Vic 3800, Australia.
    Hultqvist, Adam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Tian
    Monash Univ, Dept Mat Engn, Clayton, Vic 3800, Australia.
    Jiang, Liangcong
    Monash Univ, Dept Mat Engn, Clayton, Vic 3800, Australia.
    Ruan, Changqing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Yang, Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Cheng, Yibing
    Monash Univ, Dept Mat Engn, Clayton, Vic 3800, Australia.
    Edoff, Marika
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Johansson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Al2O3 Underlayer Prepared by Atomic Layer Deposition for Efficient Perovskite Solar Cells.2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 19, p. 3810-3817Article in journal (Refereed)
    Abstract [en]

    Perovskite solar cells, as an emergent technology for solar energy conversion, have attracted much attention in the solar cell community by demonstrating impressive enhancement in power conversion efficiencies. However, the high temperature and manually processed TiO2 underlayer prepared by spray pyrolysis significantly limit the large-scale application and device reproducibility of perovskite solar cells. In this study, lowtemperature atomic layer deposition (ALD) is used to prepare a compact Al2 O3 underlayer for perovskite solar cells. The thickness of the Al2 O3 layer can be controlled well by adjusting the deposition cycles during the ALD process. An optimal Al2 O3 layer effectively blocks electron recombination at the perovskite/fluorine-doped tin oxide interface and sufficiently transports electrons through tunneling. Perovskite solar cells fabricated with an Al2 O3 layer demonstrated a highest efficiency of 16.2 % for the sample with 50 ALD cycles (ca. 5 nm), which is a significant improvement over underlayer-free PSCs, which have a maximum efficiency of 11.0 %. Detailed characterization confirms that the thickness of the Al2 O3 underlayer significantly influences the charge transfer resistance and electron recombination processes in the devices. Furthermore, this work shows the feasibility of using a high band-gap semiconductor such as Al2 O3 as the underlayer in perovskite solar cells and opens up pathways to use ALD Al2 O3 underlayers for flexible solar cells.

  • 39.
    Zhang, Xiaoliang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Aitola, Kerttu
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Hägglund, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kaskela, Antti
    Aalto Univ, Nanomat Grp, Dept Appl Phys, POB 15100, FI-00076 Espoo, Finland..
    Johansson, Malin B.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Sveinbjörnsson, Kári
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Kauppinen, Esko I.
    Aalto Univ, Nanomat Grp, Dept Appl Phys, POB 15100, FI-00076 Espoo, Finland..
    Johansson, Erik M. J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Dry-Deposited Transparent Carbon Nanotube Film as Front Electrode in Colloidal Quantum Dot Solar Cells2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 2, p. 434-441Article in journal (Refereed)
    Abstract [en]

    Single-walled carbon nanotubes (SWCNTs) show great potential as an alternative material for front electrodes in photovoltaic applications, especially for flexible devices. In this work, a press-transferred transparent SWCNT film was utilized as front electrode for colloidal quantum dot solar cells (CQDSCs). The solar cells were fabricated on both glass and flexible substrates, and maximum power conversion efficiencies of 5.5 and 5.6 %, respectively, were achieved, which corresponds to 90 and 92% of an indium-doped tin oxide (ITO)-based device (6.1 %). The SWCNTs are therefore a very good alternative to the ITO-based electrodes especially for flexible solar cells. The optical electric field distribution and optical losses within the devices were simulated theoretically and the results agree with the experimental results. With the optical simulations that were performed it may also be possible to enhance the photovoltaic performance of SWCNT-based solar cells even further by optimizing the device configuration or by using additional optical active layers, thus reducing light reflection of the device and increasing light absorption in the quantum dot layer.

  • 40.
    Zhu, Huimin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Johansson, Malin B
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Johansson, Erik M.J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    The Effect of Dopant-Free Hole-Transport Polymers on Charge Generation and Recombination in Cesium-Bismuth-Iodide Solar Cells2018In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 11, no 6, p. 1114-1120Article in journal (Refereed)
    Abstract [en]

    The photovoltaic characteristics of CsBi3I10-based solar cells with three dopant-free hole-conducting polymers are investigated. The effect on charge generation and charge recombination in the solar cells using the different polymers is studied and the results indicate that the choice of polymer strongly affects the device properties. Interestingly, for the solar cell with poly[[2,3-bis(3-octyloxyphenyl)-5,8-quinoxalinediyl]-2,5-thiophenediyl] (TQ1), the photon-to-current conversion spectrum is highly improved in the red wavelength region, suggesting that the polymer also contributes to the photocurrent generation in this case. This report provides a new direction for further optimization of Bi-halide solar cells by using dopant-free hole-transporting polymers and shows that the energy levels and the interaction between the Bi-halide and the conducting polymers are very important for solar cell performance.

  • 41.
    Zhu, Huimin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Pan, Mingao
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Johansson, Malin B
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Johansson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    High Photon-to-Current Conversion in Solar Cells Based on Light-Absorbing Silver Bismuth Iodide2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 12, p. 2592-2596Article in journal (Refereed)
    Abstract [en]

    Here, a lead-free silver bismuth iodide (AgI/BiI3) with a crystal structure with space group R (3) over barm is investigated for use in solar cells. Devices based on the silver bismuth iodide deposited from solution on top of TiO2 and the conducting polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) as a hole-transport layer are prepared and the photovoltaic performance is very promising with a power conversion efficiency over 2%, which is higher than the performance of previously reported bismuth-halide materials for solar cells. Photocurrent generation is observed between 350 and 700 nm, and the maximum external quantum efficiency is around 45%. The results are compared to solar cells based on the previously reported material AgBi2I7, and we observe a clearly higher performance for the devices with the new silver and bismuth iodides composition and different crystal structure. The X-ray diffraction spectrum of the most efficient silver bismuth iodide material shows a hexagonal crystal structure with space group R (3) over barm, and from the light absorption spectrum we obtain an indirect band gap energy of 1.62 eV and a direct band gap energy of 1.85 eV. This report shows the possibility for finding new structures of metal-halides efficient in solar cells and points out new directions for further exploration of lead-free metal-halide solar cells.

1 - 41 of 41
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