Studies on chemical bath deposited SnS2 films for Cd-free thin film solar cells

Tin disulfide (SnS2) is a simple binary metal chalcogenide and it has been proposed as a promising buffer material for Cd-free thin film solar cells. The present work explores the deposition of SnS2 films by a facile chemical bath deposition at different deposition times in the range of 30-120 min. The effect of deposition time on the structural, optical and electrical properties was investigated. The as-grown SnS2 films showed a hexagonal crystal structure with a high intensity (001) peak at 15.03°. The films showed shuttle shaped grains that were uniformly distributed across the surface of the substrate. The films showed an optical energy band gap in the range of 2.95-2.80 eV. PL spectra showed a strong emission peak in the wavelength range, 410-460 nm with the variation of deposition time. The SnS2 films prepared at a deposition time of 90 min showed good crystallinity and morphology with low resistivity of 11.2 Ω-cm. A solar cell with device structure of Mo/SnS/SnS2/i-ZnO/Al: ZnO/Ni/Ag was fabricated. The fabricated solar cell showed an efficiency of 0.91%, which validate the photovoltaic performance of SnS2 films.