Regensburg 2019 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 15: Energy materials (other than photovoltaics)
HL 15.6: Vortrag
Dienstag, 2. April 2019, 10:45–11:00, H33
Impact of surface adsorbates on charge carrier transport in metal oxide semiconductors for solar water splitting — •Johanna Eichhorn1, Christoph Kastl2, Adam Schwartzberg2, Ian Sharp3, and Francesca Toma1 — 1Lawrence Berkeley National Laboratory, Chemical Sciences Division, Berkeley, United States — 2Lawrence Berkeley National Laboratory, The Molecular Foundry, Berkeley, United States — 3Technische Universität München, Walter Schottky Institute and Physics Department, Garching, Germany
Photoelectrochemical (PEC) water splitting is a promising route for efficient conversion of solar energy to chemical fuels. In this context, bismuth vanadate (BiVO4) is one of the most investigated photoanode materials. Here, we employ in-situ photoconductive atomic force microscopy to elucidate the interplay of surface interactions and interfacial charge transport in polycrystalline BiVO4 films. We demonstrate that the low intrinsic bulk conductivity limits interfacial charge transport. The transport mechanism is attributed to space charge limited current (SCLC) with shallow trap states.[1] By analyzing the SCLC in selective gas environments, we are able to quantify the impact of surface adsorbates on bulk transport. Surface adsorbed oxygen acts as a shallow trap state and accounts for 40% of the effective trap density in BiVO4 films.[2] Understanding such limitations of charge transport and transfer in photoelectrodes at the nanoscale and under in-situ conditions will enable the design of next generation PEC materials.
[1] Eichhorn et al., Nat. Commun. 9, 2597 (2018).
[2] Eichhorn et al., ACS Appl. Mater. Interfaces 10, 35129 (2018).