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

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