Correlation between some physical properties of pure and Sb doped Cu2SnS3 thin films under the effect of sulfur amount for solar cell application

Adjusting of sulfur content and amount of doping in Cu2SnS3 (CTS), as absorber layer for solar cell, is a promising approach to fabricate thin film solar cells with high performance. In this work, the effect of different amounts of sulfur in the sulfurization process and the percentage of Sb doping in the films were studied. The physical properties of un-doped and doped CTS thin films were investigated. The pure and doped CTS thin films showed a monoclinic structure, with a larger grain size under the influence of Sb doping. XPS analysis demonstrated that Cu, Sn, S, and Sb oxidation states were +1, +4, −2, and +3, respectively. The Sb-doped sample for 25 min (25Sb) has a higher Cu+1/Cu+2 ratio than other samples and no satellite peak of Sn+2 was observed as compared to other levels of doping samples. This concluded that the Cu species in the 25Sb film experienced a more Cu-rich chemical environment. Both PL and UV–Vis spectroscopy were used to obtain the optical properties. Hall Effect was applied to measure the electrical properties of un-doped and doped CTS films. The pure and Sb-doped CTS solar cells were fabricated by optimization of Sb doping time and sulfur amount. The conversion efficiency of the prepared solar cell was 2.13% when fabricated with CTS layer that treated with 25 min of Sb doping and 100 mg of sulfur, whereas the efficiency of the un-doped CTS solar cell at the same sulfur amount was just 0.615%.