n-type SnS 2 thin films spray-coated from transparent molecular ink as a non-toxic buffer layer for solar photovoltaics

This paper reports the effect of solvent evaporation temperature on spray-coated tin disulfide (SnS 2 ) thin films from molecular ink. Thiourea and tin chloride were the key chemical reagents used for the synthesis of SnS 2 transparent ink under atmospheric conditions. The structural and compositional properties of SnS 2 thin films revealed formation of pristine hexagonal SnS 2 . The films are smooth, homogeneous resulting in band gaps ranging from 2 to 2.22 eV suited for a Cd-free alternative buffer layer for Cu-based multicomponent solar cells. Thermoelectric power measurement showed that tin disulfide films exhibit n-type conductivity. Activation energy estimated from temperature variation of electrical conductivity measurement varied from 40 to 90 mV. Our results suggest that ink-processed SnS 2 can be used as a potential alternative for opto-electronic devices such as thin film solar cell and photodetector devices.