Importance of surface oxygen vacancies for ultrafast hot carrier relaxation and transport in Cu2O

DOI

Cu2O has appealing properties as an electrode for photo-electrochemical water splitting, yet its practical performance is severely limited by inefficient charge extraction at the interface. Using hybrid DFT calculations, we investigate carrier capture processes by oxygen vacancies (VO) in the experimentally observed (√3×√3)R30° reconstruction of the dominant (111) surface. Our results show that these VO are doubly ionized and that associated defects states strongly suppress electron transport. In particular, the excited electronic state of a singly charged VO plays a crucial role in the non-radiative electron capture process with a capture coefficient of about 10^-9 cm3/s and a lifetime of 0.04 ps, explaining the experimentally observed ultrafast carrier relaxation. These results highlight that engineering the surface VO chemistry will be a crucial step in optimizing Cu2O for photoelectrode applications.

Identifier
DOI https://doi.org/10.24435/materialscloud:rr-2n
Source https://archive.materialscloud.org/record/2021.39
Metadata Access https://archive.materialscloud.org/xml?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai:materialscloud.org:768
Provenance
Creator Ricca, Chiara; Aschauer, Ulrich; Grad, Lisa; Hengsberger, Matthias; Osterwalder, Jürg
Publisher Materials Cloud
Publication Year 2021
Rights info:eu-repo/semantics/openAccess; Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode
OpenAccess true
Contact archive(at)materialscloud.org
Representation
Language English
Resource Type Dataset
Discipline Materials Science and Engineering