The role of adsorbed anions as photocharge transfer mediators: Results of studies on the CdS/S-2,S-2 system in the picosecond time domain and at steady state

Results of transient and steady-state measurements are considered together in the analysis of a photocharge transfer mechanism. The authors recent study of photoluminescence decay in the picosecond time domain from CdS crystals immersed in electrolytics, revealed high capture velocities for both minority and majority carriers in OH-, S-2, SA-2 electrolyte, where specific anionic adsorption at CdS is known to occur. Computer-simulated steady-state j vs. V curves demonstrate that high conversion efficiencies will be obtained from such a junction, provided the rate constant for minority transfer from the anionic surface level to solution is reasonably high (e.g., 106s-1)