Fine tunable aqueous solution synthesis of textured flexible SnS2 thin films and nanosheets.

Films and nanosheets of layered chalcogenides are currently under intense investigation owing to their application in thin film electronic, optoelectronic, and sensor devices. Here, aqueous solution processing of the environmentally benign thiostannate, (NH4)4Sn2S6·3H2O, and its subsequent thermal decomposition to form continuous highly textured SnS2 thin films are presented. We show how to control the film thickness, the coherent scattering domain size, and the crystallinity by changes in the processing parameters (i.e. thiostannate concentration or angular velocity in the spin coating process). For device applications of the semiconducting metal sulfide film it is of interest to delaminate the film from the glass substrate to create freestanding nanosheets or transfer the film to a flexible polymer substrate. It is shown how metal sulfide films can be delaminated from the glass substrate and form large area freestanding nanosheets. Furthermore, we extend the delamination process to include transfer of the thin film from the glass substrate to a low-cost flexible polymer substrate.