Photoelectrochemical characterization of nanocrystalline ZnS : Mn2+ layers

Measurements of the photoelectrochemical properties of nanocrystalline ZnS electrodes doped with Mn2+ are presented and discussed. The observation of both anodic and cathodic photocurrent with Mn is direct evidence for the na nocrystalline nature of the system. In-situ photoluminescence: measurements showed stable Mn2+ related photoluminescence over a large: potential range . Due to the unfavourable kinetics of electron and hole transfer across the interface between the nanocrystallites and solution. it is concluded that recombination accounts for most of the charge carriers generated by illumin ation. Breakdown of the ZnS into elementary Zn and S2- in solution was also observed at negative potential. This breakdown introduces new non-radiativ e decay paths and is responsible for the slow luminescence decrease as a fu nction of operating time.