Effect of post-synthesis annealing on properties of SnS nanospheres and its solar cell performance

SnS nanospheres (NSPs) were synthesized, and the effects of thermal annealing on the structural, morphological, chemical compositional and optical properties were examined. As-synthesized SnS NPSs with a mean size of 3-4 nm underwent a solid state morphological transformation by high temperature annealing in a nitrogen environment. Upon annealing, the size of SnS NSP increased to 5-6 nm with enhanced crystallinity. Also, the photoluminescence (PL) of the nitrogen-annealed samples slightly decreased in intensity with accompanying red-shift in spectrum. The power conversion efficiency of the solar cells using a polymer and the SnS NSPs was ~0.71%. These results confirm that the SnS NSPs demonstrate a potential as an inorganic material to be used in organic-inorganic hybrid bulk heterojunction (BHJ) photovoltaic devices.