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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 56: Materials for Energy Storage II (joint session KFM/CPP)

CPP 56.7: Vortrag

Mittwoch, 14. März 2018, 17:30–17:50, EMH 025

Interaction of water with wet-chemically etched p-GaInP2(100) surface — Andreas Hajduk¹, •Mikhail Lebedev², Bernhard Kaiser¹, and Wolfram Jaegermann¹ — ¹TU Darmstadt, AG Oberflächenforschung, Otto-Berndt-Straße 3, 64287 Darmstadt — ²Ioffe Institute, Politekhnicheskaya 26, St. Petersburg, 194021 Russia

Photoelectrochemical water splitting offers the possibility to convert solar energy directly into a chemical fuel and therefore is a promising candidate for a sustainable energy solution in the future. GaInP2 with a direct bandgap of 1.8-1.9 eV shows so far the highest reported solar-to-hydrogen conversion efficiencies. Nevertheless, the fast photocorrosion of III-V semiconductors in aqueous solution presents a major obstacle for their use as efficient and stable photoelectrodes. Interaction of water with chemically etched p-GaInP2(100) surface covered with a submonolayer of residual oxides is studied by synchrotron photoemission spectroscopy to gain insight into the solid/solvent interaction at the semiconductor/electrolyte interface. Photoemission spectra obtained after emersion of the semiconductor from liquid water at room temperature and adsorption of H2O molecules at liquid-nitrogen temperature are compared to understand the chemistry of the GaInP2(100)/H2O interface. Valence band spectra indicate dissociative adsorption of water molecules both after emersion and after adsorption experiments. Surface-sensitive core level spectra reveal the interaction of H2O molecules with surface phosphorous and gallium atoms.