Open AccessUnraveling the Mechanisms of Beneficial Cu-Doping of NiO-Based Photocathodes
Author(s) -
Kaijian Zhu,
Sean K. Frehan,
Anna M. Jaros,
Devin B. O’Neill,
Jeroen P. Korterik,
Kasper Wenderich,
Guido Mul,
Annemarie Huijser
Publication year - 2021
Publication title -
journal of physical chemistry. c./journal of physical chemistry. c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 289
eISSN - 1932-7455
pISSN - 1932-7447
DOI - 10.1021/acs.jpcc.1c03553
Subject(s) - photocathode , non blocking i/o , doping , materials science , femtosecond , optoelectronics , photochemistry , chemistry , optics , physics , laser , electron , catalysis , biochemistry , quantum mechanics
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.