Nanocomposite synthesis methods using binary metal chalcogenide solids have led to the development of Kesterite Cu2ZnSnS4 (CZTS), which is an important emerging material for thin film photovoltaic devices. Nanoparticulate precursors are combined in stoichiometric ratios and annealed in a 350 degree - 500 degree C sulfur-rich nitrogen atmosphere to form CZTS. Processing methods for CZTS in the literature are energy-intensive, requiring the sequential sputtering of metal layers at 700 degrees C, followed by an annealing step in a sulfur-containing atmosphere at 500 degrees C. The presence of CZTS is clear in the resulting powders as confirmed by both XRD and UV-Vis analysis. Three conclusions were reached in this study. First, it has been found that increasing annealing temperatures corresponds to a higher level of purity of the resulting CZTS powders. Second, a copper-poor, zinc-rich environment produces the purest CZTS powders. Third, tin disulfide precursors produce a purer CZTS, despite studies concluding the successful use of tin monosulfide as a precursor. Furthermore, this synthetic route is more cost effective and environmentally friendly, avoiding the use of long processing times and harsh solvents.
