SKM 2023 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 38: Functional semiconductors for renewable energy solutions I

HL 38.2: Vortrag

Donnerstag, 30. März 2023, 09:45–10:00, POT 6

Nanoscale characterization for understanding performance limitations in water splitting photoelectrodes — Lukas Wolz¹, Harishankar Balakrishnan², Guanda Zhou¹, Ian Sharp¹, Achim Hartschuh², and •Johanna Eichhorn¹ — ¹Walter Schottky Institute, TU München, Am Coulombwall 4, 85748 Garching, Germany — ²Department of Chemistry, LMU München, Butenandtstr. 5-13, 81377 Munich, Germany

Economically viable systems for photoelectrochemical water splitting are often based of polycrystalline or nanostructured semiconductor thin films. Their nano- to micrometer properties often control critical processes, such as efficiency and stability, of the macroscale system.

Here, we aim at resolving local heterogeneities and at elucidating their effect on light-driven processes of BiVO4 thin films using a correlative nanoscale approach. Scanning nearfield infrared microscopy shows varying absorption from VO4 stretching modes across the film which correlates with local photoconductivity heterogeneities revealed by photoconductive atomic force microscopy. Furthermore, local temperature-dependent current-voltage spectroscopy in controlled gas environment shows that the low intrinsic bulk conductivity limits the electron transport [1], and that adsorbed oxygen acts as surface trap states for electrons [2]. Overall, combining insights from different nanoscale techniques generates a comprehensive picture of charge transport and transfer at the nanoscale, which provides the foundation for the rational design of durable and efficient solar fuel devices.

[1] Nat. Commun. 2597 (2018) [2] ACS Interfaces, 10, 35129 (2018)