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Publications (10 of 68) Show all publications
Zhao, J., Wen, C., Sun, R., Zhang, S.-L., Wu, B. & Zhang, Z.-B. (2019). A Sequential Process of Graphene Exfoliation and Site-Selective Copper/Graphene Metallization Enabled by Multifunctional 1-Pyrenebutyric Acid Tetrabutylammonium Salt. ACS Applied Materials and Interfaces, 11(6), 6448-6455
Open this publication in new window or tab >>A Sequential Process of Graphene Exfoliation and Site-Selective Copper/Graphene Metallization Enabled by Multifunctional 1-Pyrenebutyric Acid Tetrabutylammonium Salt
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2019 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 6, p. 6448-6455Article in journal (Refereed) Published
Abstract [en]

This paper reports a procedure leading to shear exfoliation of pristine few-layer graphene flakes in water and subsequent site-selective formation of Cu/graphene films on polymer substrates, both of which are enabled by employing the water soluble 1-pyrenebutyric acid tetrabutylammonium salt (PyB-TBA). The exfoliation with PyB-TBA as an enhancer leads to as-deposited graphene films dried at 90 °C that are characterized by electrical conductivity of ∼110 S/m. Owing to the good affinity of the tetrabutylammonium cations to the catalyst PdCl42–, electroless copper deposition selectively in the graphene films is initiated, resulting in a self-aligned formation of highly conductive Cu/graphene films at room temperature. The excellent solution-phase and low-temperature processability, self-aligned copper growth, and high electrical conductivity of the Cu/graphene films have permitted fabrication of several electronic circuits on plastic foils, thereby indicating their great potential in compliant, flexible, and printed electronics.

Keywords
graphene, electroless copper deposition, solution-phase processing, self-aligned metallization, flexible electronics
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-378999 (URN)10.1021/acsami.8b21162 (DOI)000459221900096 ()30656938 (PubMedID)
Funder
Swedish Foundation for Strategic Research , Dnr SE13-0061Swedish Research Council, 621-2014-5596
Available from: 2019-03-19 Created: 2019-03-19 Last updated: 2019-04-08Bibliographically approved
Song, M., Tahershamsi, L., Zhao, J., Zhang, Z.-B. & Grennberg, H. (2018). Efficient Gelation of Graphene Oxide Aqueous Dispersion Induced by Sonication-Promoted Leuckart Reaction. ChemNanoMat, 4(11), 1145-1152
Open this publication in new window or tab >>Efficient Gelation of Graphene Oxide Aqueous Dispersion Induced by Sonication-Promoted Leuckart Reaction
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2018 (English)In: ChemNanoMat, ISSN 2199-692X, Vol. 4, no 11, p. 1145-1152Article in journal (Refereed) Published
Abstract [en]

Abstract Graphene oxide (GO) undergoes a rapid gelation process in the presence of ammonium hydroxide and formic acid at room temperature which is promoted by ultrasonication. Infrared and X-ray photoelectron spectroscopy proved partial reduction of GO and nitrogen incorporation, resulting from sonication-promoted Leuckart reactions at GO carbonyl groups. The amine groups produced via Leuckart reactions undergo further reactions that result in salt bridges with carboxylic groups and covalent cross-links, both of which contribute to the stabilization of the resulting hydrogel. The resultant GO hydrogel exhibits enhanced thermal stability.

Keywords
Gelation, graphene oxide, hydrogels, Leuckart reaction, ultrasonication
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-363972 (URN)10.1002/cnma.201800286 (DOI)000452398900006 ()
Funder
Swedish Foundation for Strategic Research , SE13-0061Swedish Research Council, No. 621-2014-5596Knut and Alice Wallenberg Foundation
Available from: 2018-10-22 Created: 2018-10-22 Last updated: 2019-02-25
Banerjee, D., Vallin, Ö., Samani, K. M., Majee, S., Zhang, S.-L., Liu, J. & Zhang, Z.-B. (2018). Elevated thermoelectric figure of merit of n-type amorphous silicon by efficient electrical doping process. Nano Energy, 44, 89-94
Open this publication in new window or tab >>Elevated thermoelectric figure of merit of n-type amorphous silicon by efficient electrical doping process
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2018 (English)In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 44, p. 89-94Article in journal (Refereed) Published
Abstract [en]

The currently dominant thermoelectric (TE) materials used in low to medium temperature range contain Tellurium that is rare and mild-toxic. Silicon is earth abundant and environment friendly, but it is characterized by a poor TE efficiency with a low figure of merit, ZT. In this work, we report that ZT of amorphous silicon (a-Si) thin films can be enhanced by 7 orders of magnitude, reaching similar to 0.64 +/- 0.13 at room temperature, by means of arsenic ion implantation followed by low-temperature dopant activation. The dopant introduction employed represents a highly controllable doping technique used in standard silicon technology. It is found that the significant enhancement of ZT achieved is primarily due to a significant improvement of electrical conductivity by doping without crystallization so as to maintain the thermal conductivity and Seebeck coefficient at the level determined by the amorphous state of the silicon films. Our results open up a new route towards enabling a-Si as a prominent TE material for cost-efficient and environment-friendly TE applications at room temperature.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2018
Keywords
Thermoelectrics, Amorphous silicon, Electrical conductivity, Electrical doping, Energy harvesting
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-341565 (URN)10.1016/j.nanoen.2017.11.060 (DOI)000419833900011 ()
Funder
Swedish Research Council, 621-2014-5596Swedish Foundation for Strategic Research , SE13-0061
Available from: 2018-02-12 Created: 2018-02-12 Last updated: 2018-02-27Bibliographically approved
Guo, J., Wang, M., Dong, G., Zhang, Z.-B., Zhang, Q., Yu, H., . . . Diao, X. (2018). Mechanistic Insights into the Coloration, Evolution, and Degradation of NiOx Electrochromic Anodes. Inorganic Chemistry, 57(15), 8874-8880
Open this publication in new window or tab >>Mechanistic Insights into the Coloration, Evolution, and Degradation of NiOx Electrochromic Anodes
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2018 (English)In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 57, no 15, p. 8874-8880Article in journal (Refereed) Published
Abstract [en]

NiOx is recognized as the leading candidate for smart window anodes that can dynamically modulate optical absorption, thereby achieving energy efficiency in construction buildings. However, the electrochromic mechanism in NiOx is not yet clear, and the ionic species involved are sometimes ambiguous, particularly in aprotic electrolytes. We demonstrate herein that the "net coloration effect" originates from newly generated high-valence Ni3+/Ni4+ ions during anion-dependent anodization, and the Li+ intercalation/deintercalation only plays a role in modulating the oxidation state of Ni. Unambiguous evidences proving the occurrence of anodization reaction were obtained by both chronoamperometry and cyclic voltammetry. Benefiting from the irreversible polarization of Ni2+ to Ni3+/Ni4+, the quantity of voltammetric charge increases by similar to 38% under the same test conditions, enhancing the corresponding electrochromic modulation by similar to 8%. Strong linkages between the coloration, evolution, and degradation observed in this work provide in-depth insights into the electrocatalytic and electrochromic mechanisms.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
National Category
Inorganic Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-365828 (URN)10.1021/acs.inorgchem.8b00793 (DOI)000441477100025 ()30047734 (PubMedID)
Available from: 2018-11-26 Created: 2018-11-26 Last updated: 2018-11-26Bibliographically approved
Zhao, J., Song, M., Wen, C., Majee, S., Yang, D., Wu, B., . . . Zhang, Z.-B. (2018). Microstructure-tunable highly conductive graphene-metal composites achieved by inkjet printing and low temperature annealing. Journal of Micromechanics and Microengineering, 28(3), Article ID 035006.
Open this publication in new window or tab >>Microstructure-tunable highly conductive graphene-metal composites achieved by inkjet printing and low temperature annealing
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2018 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 28, no 3, article id 035006Article in journal (Refereed) Published
Abstract [en]

We present a method for fabricating highly conductive graphene-silver composite films with a tunable microstructure achieved by means of an inkjet printing process and low temperature annealing. This is implemented by starting from an aqueous ink formulation using a reactive silver solution mixed with graphene nanoplatelets (GNPs), followed by inkjet printing deposition and annealing at 100 degrees C for silver formation. Due to the hydrophilic surfaces and the aid of a polymer stabilizer in an aqueous solution, the GNPs are uniformly covered with a silver layer. Simply by adjusting the content of GNPs in the inks, highly conductive GNP/Ag composites (> 106 S m(-1)), with their microstructure changed from a large-area porous network to a compact film, is formed. In addition, the printed composite films show superior quality on a variety of unconventional substrates compared to its counterpart without GNPs. The availability of composite films paves the way to the metallization in different printed devices, e.g. interconnects in printed circuits and electrodes in energy storage devices.

Place, publisher, year, edition, pages
IOP PUBLISHING LTD, 2018
Keywords
graphene, composite, inkjet printing
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-345709 (URN)10.1088/1361-6439/aaa450 (DOI)000423867400001 ()
Funder
Swedish Foundation for Strategic Research , Dnr SE13-0061Swedish Research Council, 621-2014-5596
Available from: 2018-03-14 Created: 2018-03-14 Last updated: 2019-04-08Bibliographically approved
Guo, J., Wang, M., Diao, X., Zhang, Z.-B., Dong, G., Yu, H., . . . Liu, J. (2018). Prominent Electrochromism Achieved Using Aluminum Ion Insertion/Extraction in Amorphous WO3 Films. The Journal of Physical Chemistry C, 122(33), 19037-19043
Open this publication in new window or tab >>Prominent Electrochromism Achieved Using Aluminum Ion Insertion/Extraction in Amorphous WO3 Films
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2018 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 33, p. 19037-19043Article in journal (Refereed) Published
Abstract [en]

Although monovalent lithium has been successfully used as a coloring ion in electrochromic applications, it still faces the challenges of low safety, high cost, and limited reserves. Herein, we demonstrate that the amorphous WO3 films intercalated with Al3+ ions could exhibit desired wide optical modulation (similar to 63.0%) and high coloration efficiency (similar to 72.0 cm(2) A(-1), which is >100% higher than that with Li+ or Na+), benefiting from the three-electron redox properties of aluminum. Due to the strong electrostatic force and large atomic weight, the charge exchange processes for Al3+ ions are limited only to the near-surface region and consequently bring about enhanced electrochromic stability. Our findings provide in-depth insights into the nature of electrochromism and also open up a new route toward scalable electrochromic devices using sputtering techniques and earth-abundant materials.

National Category
Condensed Matter Physics Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-364047 (URN)10.1021/acs.jpcc.8b05692 (DOI)000442960300027 ()
Funder
Swedish Research Council
Available from: 2018-12-10 Created: 2018-12-10 Last updated: 2018-12-11Bibliographically approved
Hinnemo, M., Makaraviciute, A., Ahlberg, P., Olsson, J., Zhang, Z., Zhang, S.-L. & Zhang, Z.-B. (2018). Protein sensing beyond the Debye Length Using Graphene Field-effect Transistors. IEEE Sensors Journal, 18(16), 6497-6503
Open this publication in new window or tab >>Protein sensing beyond the Debye Length Using Graphene Field-effect Transistors
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2018 (English)In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 18, no 16, p. 6497-6503Article in journal (Refereed) Published
Abstract [en]

Sensing biomolecules in electrolytes of high ionic strength has been a difficult challenge for field-effect transistor-based sensors. Here, we present a graphene-based transistor sensor that is capable of detection of antibodies against protein p53 in electrolytes of physiological ionic strength without dilution. As these molecules are much larger than the Debye screening length at physiological ionic strengths, this paper proves the concept of detection beyond the Debye length. The measured signal associated with the expected specific binding of the antibodies to p53 is concluded to result from resistance changes at the graphene-electrolyte interface, since a sensor responding to resistance changes rather than charge variations is not limited by Debye screening. The conclusion with changes in interface resistance as the underlying phenomena that lead to the observed signal is validated by impedance spectroscopy, which indeed shows an increase of the total impedance in proportion to the amounts of bound antibodies. This finding opens up a new route for electrical detection of large-size and even neutral biomolecules for biomedical detection applications with miniaturized sensors.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-317088 (URN)10.1109/JSEN.2018.2849006 (DOI)000439966100003 ()
Funder
Knut and Alice Wallenberg Foundation, 2011.0113 2011.0082Swedish Foundation for Strategic Research , SE13-0061Swedish Research Council, 2014-5591 2014-5588
Available from: 2017-03-10 Created: 2017-03-10 Last updated: 2018-11-12Bibliographically approved
Zhao, J., Zeng, S., Wu, B., Zhang, S.-L. & Zhang, Z.-B. (2018). Re-organized graphene nanoplatelet thin films achieved by a two-step hydraulic method. Diamond and related materials, 84, 141-145
Open this publication in new window or tab >>Re-organized graphene nanoplatelet thin films achieved by a two-step hydraulic method
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2018 (English)In: Diamond and related materials, ISSN 0925-9635, E-ISSN 1879-0062, Vol. 84, p. 141-145Article in journal (Refereed) Published
Abstract [en]

Film deposition of graphene nanoplatelets (GNPs) from dispersion via casting and printing approaches features cost- and material-efficiency, however, it usually suffers from poor uniformity, rough surface and loose flake stacking due to adverse effect of hydraulic force. Here, a simple two-step method exploiting hydraulic force is presented to readily deliver GNP films of improved quality from an aqueous dispersion. While as-deposited GNP films exhibit the aforementioned film defects, the hydraulic force in the subsequent step constituting soaking in water and drying leads to an efficient re-organization of the individual GNPs in the films, The majority of GNPs thus are oriented horizontally and closely stacked. As a result, densified, smoothened and homogenized GNP thin films can be readily achieved. The GNP re-organization reduces resistivity from > 1 Omega cm to 10(-2) Omega cm. The method developed is universally applicable to solution-phase film deposition of 2D materials.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2018
National Category
Composite Science and Engineering
Identifiers
urn:nbn:se:uu:diva-356327 (URN)10.1016/j.diamond.2018.03.016 (DOI)000432101800019 ()
Funder
Swedish Foundation for Strategic Research , Dnr SE13-0061Swedish Research Council, 621-2014-5596
Available from: 2018-07-26 Created: 2018-07-26 Last updated: 2019-04-08Bibliographically approved
Song, M., Zhao, J., Grennberg, H. & Zhang, Z.-B. (2018). Screen Printed Conductive Composites with Reduced Graphene Oxide and Silver. In: 2018 IMAPS Nordic Conference on Microelectronics Packaging (NordPac): . Paper presented at 2018 IMAPS Nordic Conference on Microelectronics Packaging (NordPac), 12th – 14th June 2018, Oulu, Finland (pp. 35-39).
Open this publication in new window or tab >>Screen Printed Conductive Composites with Reduced Graphene Oxide and Silver
2018 (English)In: 2018 IMAPS Nordic Conference on Microelectronics Packaging (NordPac), 2018, p. 35-39Conference paper, Published paper (Refereed)
Abstract [en]

This work provides a method to fabricate conductive composites by screen printing of aqueous hybrid inks with graphene oxide (GO) and silver acetate as silver source. The formulation of the aqueous hybrid inks is realized by mixing highly concentrated GO solution and reactive silver solution, which readily results in a formation of viscous pastes. Composite films with four-probe structure were fabricated by means of blade coating, followed by annealing at 160 °C in air and subsequently at 600 °C in Ar/H 2 . While the reactive silver solution without GO can be completely reduced when annealed at 90 °C in air, resulting in elemental Ag films with resistivity close to the bulk value, no reduction occurs in the hybrid inks under the same annealing condition. Silver nanoparticles are formed from the hybrid inks at 160 °C and discretely distributed on the reduced GOs (rGOs), which shows a retardation effect of GO on the reduction of silver. Further annealing at 600 °C in Ar/H 2 leads to partial restoration of sp 2 lattice in the rGOs. The resistivity of the composite films increases as the silver content is increased, which is interpreted by using a percolation model with rGO networks.

Keywords
annealing, coatings, electrical conductivity, electrical resistivity, graphene compounds, mixing, nanocomposites, nanofabrication, nanoparticles, percolation, reduction (chemical), silver, thin films, aqueous hybrid inks, silver acetate, reactive silver solution, silver nanoparticles, reduced graphene oxide, screen printed conductive composites, viscous pastes, four-probe structure, blade coating, retardation effect, percolation model, temperature 160.0 degC, temperature 600.0 degC, temperature 90.0 degC, CO-Ag, Ink, Films, Conductivity, Printing, Graphene, graphene oxide, conductive composite, screen printing
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-363974 (URN)10.23919/NORDPAC.2018.8423856 (DOI)
Conference
2018 IMAPS Nordic Conference on Microelectronics Packaging (NordPac), 12th – 14th June 2018, Oulu, Finland
Funder
Swedish Research Council, No. 621-2014-5596Swedish Foundation for Strategic Research , Dnr SE13-0061
Available from: 2018-10-22 Created: 2018-10-22 Last updated: 2019-03-14Bibliographically approved
Tian, L., Föhlinger, J., Zhang, Z.-B., Pati, P. B., Lin, J., Kubart, T., . . . Tian, H. (2018). Solid state p-type dye sensitized NiO-dye-TiO2 core-shell solar cells. Chemical Communications, 54(30), 3739-3742
Open this publication in new window or tab >>Solid state p-type dye sensitized NiO-dye-TiO2 core-shell solar cells
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2018 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 54, no 30, p. 3739-3742Article in journal (Refereed) Published
Abstract [en]

Solid state p-type dye sensitized NiO-dye-TiO2 core-shell solar cells with an organic dye PB6 were successfully fabricated for the first time. With Al2O3 as an inner barrier layer, the recombination process between injected holes in NiO and injected electrons in TiO2 was significantly suppressed and the charge transport time was also improved.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2018
National Category
Physical Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-352467 (URN)10.1039/c8cc00505b (DOI)000429592700013 ()29589009 (PubMedID)
Funder
Swedish Energy Agency, 43599-1
Available from: 2018-06-08 Created: 2018-06-08 Last updated: 2018-06-14Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-0244-8565

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