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

[Display omitted] • Cu 2 SnS 3 thin films were deposited using the spray pyrolysis deposition. • Stable basic molecular solution is used as spray precursor using ethylenediamine as capping agent. • The effect of the most important parameters including the substrate temperature and copper concentration was investigated. • Qualified thin films with suitable microstructure and composition could be deposited at 370℃. • Carrier concentration of the samples rise as the Cu/Sn ratio is enhanced and Cu/Sn = 1 show a semiconductor behavior. This work focused on the spray pyrolysis deposition of Cu 2 SnS 3 (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%. [ABSTRACT FROM AUTHOR]