Crystalline phase evolution in CuSbS2 solar absorber thin films fabricated via spray pyrolysis

Among the various types of solar cells, thin film solar cells stand out for their affordability, durability, and lightness. CuSbS2 as an absorber in thin film solar cells holds a particular appeal due to its unique characteristics such as high absorption coefficient, suitable band gap, and high p-type carrier concentrations. One of the major challenges in the production of CuSbS2 thin films is related to the probability of different phases/materials formation including Cu–Sb–S ternary and S–Sb, Cu–S binary compounds. Consequently, a competition arises among the formation of aforementioned system compounds, which can be affected by the growth conditions. The aim of this study was to understand the evolution of the formation of different binary and ternary compounds during the growth of the CuSbS2 layer by the spray pyrolysis technique, which is essential for tailoring the material’s properties for solar applications. To this end, the effect of different growth conditions including Cu:Sb ratio, substrate temperature, and spraying rate were investigated. It has been demonstrated that these growth parameters significantly influence the microstructural and optical properties of CuSbS2 layers. The experimental approach presented in this study is of general interest for the fabrication of CuSbS2 layers by spray pyrolysis technique, and it can shed light on the relationship between synthesizing conditions and binary and/or ternary crystalline phase evolution.