Time resolved photocurrent, photopotential, and photoluminescence studies of n-type CdS and CdSe photoelectrodes

Transients of photocurrents and photopotentials in a PEC, based on (single crystal) CdS or CdSe/S^2-,S⁰ junctions, were generated by pulses of ns width. The results reveal strong effects of surface damage caused by mechanical polishing. Lowered transport rates and recombinative losses are detected by the current measurement mode, while the photopotential transients are interpreted in terms of incomplete charge separation in a damaged layer due to trapping, as well as surface recombination effects. Time resolved photoluminescence studies, measured using pulses of ps duration, allow detection of ultrafast recombination processes and reveal the energetic location and dynamics of some midgap centers in the single crystal material.