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

We introduce a straightforward route to the fabrication of metal sulfide semiconductor (e.g. CdS, Sb(2)S(3), Bi(2)S(3)) sensitised TiO(2) 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/TiO(2) interface. Moreover, a high yield of long-lived photogenerated charges is observed in a three-component TiO(2)/metal sulfide/spiro-OMeTAD film, thus demonstrating the potential of such multicomponent films for solar energy conversion devices.