Optoelectrical and structural characterization of Cu2SnS3 thin films grown via spray pyrolysis using stable molecular ink

Abstract This work focused on the spray pyrolysis deposition of Cu2SnS3 (CTS) thin films using a stable basic solution. The effect of the most important parameters including the substrate temperature and copper concentration on the structural, optical and electrical properties of as-deposited thin films was investigated. Qualified thin films with suitable microstructure and composition could be deposited at 370℃. XRD and Raman analysis while confirming the pure CTS film formation, show that as the Cu/Sn decreases, the crystal structure layers are changed from the tetragonal phase to the cubic phase mixed with Sn-rich phases. The optical study shows its band gap between 1.08 and 1.2 eV for different Cu/Sn ratios with the absorption coefficient being more than 10 4 cm - 1 . The Hall and Mott-Schottky measurements reveal that all samples show a p-type behavior and carrier concentration of the samples rise as the Cu/Sn ratio is enhanced. A full spray superstrate solar cell based on CTS (Cu/Sn = 1 with a semiconductor behavior) resulted in an efficiency of 0.63%.