Effect of drying temperature on the structural and optical characteristics of Cu2SnS3 thin films synthesized by simple spin coating technique

Thin films of Cu2SnS3 (CTS) were successfully prepared, by sol–gel spin coating technique on glass substrates. In this work, the effect of drying temperature on structural, morphological and optical characteristics is investigated. The X-ray diffraction patterns of the samples proved the polycrystalline nature and the formation of pure tetragonal Cu2SnS3 structure with (112) preferential orientation. The AFM and SEM images revealed that the CTS films have continuous and dense morphology. The average crystallite sizes calculated using the Debye–Scherrer formula increased from 3 to 6 nm and the direct optical band gap increased from 1.10 to 1.34 eV with increasing drying temperature from 150 to 300 °C. We found that by increasing the drying temperature, the sheet resistance decreased from 500 to 320 Ω. This makes the material as a good candidate for low cost and friendly environment thin film solar cells.