title: Efficient water reduction with gallium phosphide nanowires.
abstract: Photoelectrochemical hydrogen production from solar energy and water offers a clean and sustainable fuel option for the future. Planar III/V material systems have shown the highest efficiencies, but are expensive. By moving to the nanowire regime the demand on material quantity is reduced, and new materials can be uncovered, such as wurtzite gallium phosphide, featuring a direct bandgap. This is one of the few materials combining large solar light absorption and (close to) ideal band-edge positions for full water splitting. Here we report the photoelectrochemical reduction of water, on a p-type wurtzite gallium phosphide nanowire photocathode. By modifying geometry to reduce electrical resistance and enhance optical absorption, and modifying the surface with a multistep platinum deposition, high current densities and open circuit potentials were achieved. Our results demonstrate the capabilities of this material, even when used in such low quantities, as in nanowires.
authors.affiliation: 1] Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands [2] BioSolar Cells, P.O. Box 98, 6700 AB Wageningen, The Netherlands.
authors.forename: Anthony
authors.initials: A
authors.lastname: Standing
authors.affiliation: Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
authors.forename: Simone
authors.initials: S
authors.lastname: Assali
authors.affiliation: Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
authors.forename: Lu
authors.initials: L
authors.lastname: Gao
authors.affiliation: 1] Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands [2] Philips Innovation Services Eindhoven, High Tech Campus 11, 5656AE Eindhoven, The Netherlands.
authors.forename: Marcel A
authors.initials: MA
authors.lastname: Verheijen
authors.affiliation: Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
authors.forename: Dick
authors.initials: D
authors.lastname: van Dam
authors.affiliation: Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
authors.forename: Yingchao
authors.initials: Y
authors.lastname: Cui
authors.affiliation: 1] Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands [2] Forschungszentrum Jülich (IEK-9), D-52425 Jülich, Germany.
authors.forename: Peter H L
authors.initials: PH
authors.lastname: Notten
authors.affiliation: Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
authors.forename: Jos E M
authors.initials: JE
authors.lastname: Haverkort
authors.affiliation: 1] Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands [2] Kavli Institute of Nanoscience Delft, Delft University of Technology, 2628 CJ Delft, The Netherlands.
authors.forename: Erik P A M
authors.initials: EP
authors.lastname: Bakkers