Thermal decomposition of solution processable metal xanthates on mesoporous titanium dioxide films: a new route to quantum-dot sensitised heterojunctions

Abstract

We introduce a straightforward route to the fabrication of metal sulfide semiconductor (e.g. CdS, Sb₂S₃, Bi₂S₃) sensitised TiO₂ films. Our approach is based upon the controllable thermal decomposition of a single-source metal xanthate precursor on a mesoporous metal oxide film. The growth of the metal sulfide deposit is confirmed by Raman and UV-Vis steady-state absorption measurements. Transient absorption spectroscopy measurements provide evidence for charge separation across the metal sulfide/TiO₂ interface. Moreover, a high yield of long-lived photogenerated charges is observed in a three-component TiO₂/metal sulfide/spiro-OMeTAD film, thus demonstrating the potential of such multicomponent films for solar energy conversion devices.