Photocurrent Recombination through Surface Segregation in Al-Cr-Fe-O Photocathodes

Stein, H.S. and Zhang, S. and Li, Y. and Scheu, C. and Ludwig, Al.

Volume: Pages:
DOI: 10.1515/zpch-2019-1459
Published: 2019

Chemical surface segregation is a design variable in the optimization of phocathodes but has largely been investigated through surface passivation or decoration. In this study a long charge carrier lifetime material, Al-Cr-Fe-O, exhibiting strong photocurrent recombination is investigated for its atomic scale crystallographic and chemical inhomogeneity. Combined scanning transmission electron microscopy and atom probe tomography unveils that insulating Al- and Cr-rich surface layers form during processing. These are discussed to be the primary reason for experimentally observed charge carrier recombination. This study highlights the importance of processing in the design, discovery and optimization of new light absorber materials for photoelectrochemical water splitting. ©2019 Walter de Gruyter GmbH, Berlin/Boston.

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