Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 24: Functional Semiconductors for Renewable Energy Solutions (joint session HL/KFM)

HL 24.9: Vortrag

Mittwoch, 7. September 2022, 17:30–17:45, H36

Tuning the electrochemical properties of multifunctional CoO_x catalyst layers by plasma-enhanced atomic layer deposition — •Matthias Kuhl, Gabriel Grötzner, Laura Wagner, Alex Henning, Ian Sharp, and Johanna Eichhorn — Walter Schottky Institute, Technical University of Munich, Munich, Germany

Artificial photosynthetic systems are often limited by the poor efficiency and material instability of photoelectrodes under harsh PEC conditions. One strategy towards stable and efficient systems is to interface the semiconductor light absorber with conformal and ultra-thin catalytic layers, which still permit interfacial charge transport and minimize losses due to parasitic light absorption. In this context, conformal, biphasic Co₃O₄/Co(OH)₂ catalyst layers were fabricated by means of plasma-enhanced atomic layer deposition (PE-ALD), which are simultaneously robust and electrochemically active. The nanocrystalline Co₃O₄ layer forms a durable interface to the substrate and the disordered Co(OH)₂ surface layer significantly improves the electrocatalytic oxygen evolution reaction activity. Here, we show that non-saturated oxidation reactions can be applied to tune catalytic activity, chemical stability, and physical properties of the PE-ALD layer by leveraging low plasma exposure time and low plasma power. Based on these insights, the CoO_x films are interfaced with polycrystalline semiconductor thin films to generate highly stable and efficient multilayer photoelectrode assemblies. Overall, this work highlights the use of PE-ALD as a promising approach for engineering catalyst/semiconductor interfaces to create efficient and stable photoelectrodes.