SKM 2023 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 45: Functional semiconductors for renewable energy solutions II
HL 45.1: Vortrag
Donnerstag, 30. März 2023, 15:00–15:15, POT 6
Engineering interfaces in multilayer photoanodes for stable and efficient solar energy conversion — •Katarina-Sophie Flashar, Matthias Kuhl, Gabriel Grötzner, Laura Wagner, Lukas Wolz, Alex Henning, Ian D. Sharp, and Johanna Eichhorn — Walter Schottky Institute and Physics Department, Technical University Munich, Am Coulombwall 4, 85748 Garching, Germany
Photoelectrochemical (PEC) energy conversion is a promising approach for the direct conversion of solar energy into storable chemical fuels. In this context, tantalum nitride (Ta3N5) has attracted considerable interest due to a theoretical photocurrent density limit of 12.9 mA*cm−2 and a theoretical solar-to-hydrogen conversion efficiency of 15% under AM 1.5G illumination. However, currently Ta3N5 photoelectrodes suffer from poor stability, such as oxidative decomposition, under the harsh PEC operation conditions. To overcome these limitations, we investigate the protection of Ta3N5 photoelectrodes with ultra-thin catalyst layers deposited via plasma-enhanced atomic layer deposition. In these multilayer architectures, the metal oxide catalyst decreases the activation energy, provides active sites for water oxidation, and promotes charge extraction of photogenerated holes. Here, we use a combination of spectroscopic and microscopic methods to elucidate the impact on interfacial energetics, defect properties, charge transport, recombination, and catalytic reactions. The gained understanding of interfacial properties is applied to design efficient interfaces between semiconductor photoelectrodes and functional catalyst coatings for the realization of highly stable and efficient PEC systems.