Recently, Thomas Wågberg, Joakim Ekspong, and Robin Sandström participated in the NT16 conference held in the University of Vienna, Austria, and here are some pictures. Thomas giving a talk entitled: "Fabrication of One Dimensional Zig-Zag [6,6]-Phenyl-C61-butyric acid methyl ester Nanoribbons from Two Dimensional Nanosheets", see the conference summary here. (Picture taken from the NT16 conference web site) Joakim presented his most recent work "Stabilizing Active Edge Sites in Semicrystalline Molybdenum Sulfide by Anchorage on Nitrogen-Doped Carbon Nanotubes for Hydrogen Evolution Reaction", see his poster here. And here are the rest of the pictures, enjoy them. (Pictures taken from the NT16 conference web site)
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In our most recent publication, a donor-acceptor-donor (D-A-D) molecule has been designed and synthesized for use as the electron-donating material for organic solar cells. The D-A-D molecule (ZOPTAN-TPA) features a low HOMO level of −5.2 eV and an optical energy gap of 2.1 eV. Our best organic solar cell exhibited a power conversion efficiency of 1.9% and a high open-circuit voltage of 1.0 V. This work was developed together with the research groups of Prof. Bertil Eliasson, and Prof. Ludvig Edman. Javed Iqbal, Jenny Enevold, Christian Larsen, Jia Wang, Srikanth Revoju, Hamid Reza Barzegar, Thomas Wågberg, Bertil Eliasson, and Ludvig Edman. Solar Energy Materials and Solar Cells, 155, 348–355 (2016) DOI: 10.1016/j.solmat.2016.06.018 Abstract A donor-acceptor-donor (D-A-D) molecule has been designed and synthesized for use as the electron-donating material in solution-processed small-molecule organic solar cells (OSCs). The D-A-D molecule comprises a central electron-accepting (2Z,2′Z)-2,2′-(2,5-bis(octyloxy)-1,4-phenylene)bis(3-(thiophen-2-yl)acrylonitrile) (ZOPTAN) core, which is chemically connected to two peripheral and electron-donating triphenylamine (TPA) units. The ZOPTAN-TPA molecule features a low HOMO level of −5.2 eV and an optical energy gap of 2.1 eV. Champion OSCs based on a solution-processed and non-annealed active-material blend of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and ZOPTAN-TPA in a mass ratio of 2:1 exhibits a power conversion efficiency of 1.9% and a high open-circuit voltage of 1.0 V.
This time we report an artificial-leaf device where NiCo2O4 nanorods are used as bifunctional electrode that it can operate as both anode and cathode in the same alkaline solution. By driving two such identical electrodes with a perovskite photovoltaic assembly, a wired artificial-leaf device is obtained that features a Faradaic H2 evolution efficiency of 100%, and a solar-to-hydrogen conversion efficiency of 6.2%. This work was carried out in close collaboration with the research groups of Prof. Edman and Prof. Messinger. The article is published in the journal of Advanced Energy Materials as open access.
AbstractMolecular hydrogen can be generated renewably by water splitting with an “artificial-leaf device”, which essentially comprises two electrocatalyst electrodes immersed in water and powered by photovoltaics. Ideally, this device should operate efficiently and be fabricated with cost-efficient means using earth-abundant materials. Here, a lightweight electrocatalyst electrode, comprising large surface-area NiCo2O4 nanorods that are firmly anchored onto a carbon–paper current collector via a dense network of nitrogen-doped carbon nanotubes is presented. This electrocatalyst electrode is bifunctional in that it can efficiently operate as both anode and cathode in the same alkaline solution, as quantified by a delivered current density of 10 mA cm−2 at an overpotential of 400 mV for each of the oxygen and hydrogen evolution reactions. By driving two such identical electrodes with a solution-processed thin-film perovskite photovoltaic assembly, a wired artificial-leaf device is obtained that features a Faradaic H2 evolution efficiency of 100%, and a solar-to-hydrogen conversion efficiency of 6.2%. A detailed cost analysis is presented, which implies that the material-payback time of this device is of the order of 100 days.
We report the production of a hybrid catalyst electrode comprising semicrystalline molybdenum sulfide (MoS2+x) attached on nitrogen-doped carbon nanotubes. The nitrogen-doping of the carbon nanotubes stabilizes a semicrystalline structure of MoS2+x with a high exposure of active sites for HER resulting in enhanced catalytic activity. The results are published in the journal of Advanced Functional Materials. Joakim Ekspong, Tiva Sharifi, Andrey Shchukarev, Alexey Klechikov, Thomas Wågberg, and Eduardo Gracia-Espino. Adv. Funct. Mater, 2016. DOI: 10.1002/adfm.201601994 Abstract Finding an abundant and cost-effective electrocatalyst for the hydrogen evolution reaction (HER) is crucial for a global production of hydrogen from water electrolysis. This work reports an exceptionally large surface area hybrid catalyst electrode comprising semicrystalline molybdenum sulfide (MoS2+x) catalyst attached on a substrate based on nitrogen-doped carbon nanotubes (N-CNTs), which are directly grown on carbon fiber paper (CP). It is shown here that nitrogen-doping of the carbon nanotubes improves the anchoring of MoS2+x catalyst compared to undoped carbon nanotubes and concurrently stabilizes a semicrystalline structure of MoS2+x with a high exposure of active sites for HER. The well-connected constituents of the hybrid catalyst are shown to facilitate electron transport and as a result of the good attributes, the MoS2+x/N-CNT/CP electrode exhibits an onset potential of −135 mV for HER in 0.5 m H2SO4, a Tafel slope of 36 mV dec−1, and high stability at a current density of −10 mA cm−2.
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Featured publicationsComprehensive Study of an Earth-Abundant Bifunctional 3D Electrode for Efficient Water Electrolysis in Alkaline Medium.
ACS Appl. Mater. Interfaces, 2015, 7, 28148 Fabrication of One-Dimensional Zigzag [6,6]-Phenyl-C61-Butyric Acid Methyl Ester Nanoribbons from Two-Dimensional Nanosheets.
ACS Nano, 2015, 9, 10516 Hierarchical self-assembled structures based on nitrogen-doped carbon nanotubes as advanced negative electrodes for Li-ion batteries and 3D microbatteries.
J. P. Sources, 2015, 279, 581 .Self-Assembly Synthesis of Decorated Nitrogen-Doped Carbon Nanotubes with ZnO Nanoparticles: Anchoring Mechanism and the Effects of Sulfur.
J. Phys. Chem. C, 120, 27849 (2016) Sn/Be Sequentially co-doped Hematite Photoanodes for Enhanced Photoelectrochemical Water Oxidation: Effect of Be2+ as co-dopant.
Sci Rep. 2016; 6: 23183. Atomistic understanding of the origin of high oxygen reduction electrocatalytic activity of cuboctahedral Pt3Co–Pt core–shell nanoparticles.
Catal. Sci. Technol., 2016, 6, 1393-1401 Photocatalytic reduction of CO2 with H2O over modified TiO2 nanofibers: Understanding the reduction pathway.
Nano Res. (2016) 9: 1956. |