Unraveling the Mechanisms of Beneficial Cu-Doping of NiO-Based Photocathodes

Kaijian Zhu, Sean Kotaro Frehan, Anna Jaros, Devin Brent O'Neill, J.P. Korterik, Kasper Wenderich, Guido Mul, A. Huijser*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Dye-sensitized photoelectrochemical (DSPEC) water splitting is an attractive approach to convert and store solar energy into chemical bonds. However, the solar conversion efficiency of a DSPEC cell is typically low due to a poor performance of the photocathode. Here, we demonstrate that Cu-doping improves the performance of a functionalized NiO-based photocathode significantly. Femtosecond transient absorption experiments show longer-lived photoinduced charge separation for the Cu:NiO-based photocathode relative to the undoped analogue. We present a photophysical model that distinguishes between surface and bulk charge recombination, with the first process (∼10 ps) occurring more than 1 order of magnitude faster than the latter. The longer-lived photoinduced charge separation in the Cu:NiO-based photocathode likely originates from less dominant surface recombination and an increased probability for holes to escape into the bulk and to be transported to the electrical contact of the photocathode. Cu-doping of NiO shows promise to suppress detrimental surface charge recombination and to realize more efficient photocathodes.
Original languageEnglish
JournalJournal of physical chemistry C
DOIs
Publication statusE-pub ahead of print/First online - 16 Jul 2021

Keywords

  • UT-Hybrid-D

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