Design criteria of transition metal dopants in TiO<inf>2</inf>/CdS photoelectrode for enhanced photovoltaic response

We investigated transition metals (nickel (Ni), manganese (Mn) and iron (Fe)) doping in TiO2/CdS photoelectrodes for understanding their impact on photovoltaic performance. The work function of the transition metal is considered as the parameter of choice in evaluating and comparing their photovoltaic response. We observed that the photocurrent is enhanced up to 34% with Mn doping and reduced up to 20% and 87% with Ni and Fe doping, respectively. Further, the electron lifetime measurements revealed that average electron lifetime for Mn doped system is similar to that of the pure TiO2/CdS system and is reduced significantly for Fe doped system, causing poor photovoltaic response for Fe doped TiO2/CdS photoelectrode based devices.