Characterization of superstrate type CuInS2 solar cells deposited by spray pyrolysis method

CuInS2 films were deposited on glass/FTO/TiO2/In2S3 air ambient air at 300 °C by spray pyrolysis, resulting in superstrate-structured solar cells. The crystallinity of the spray-deposited CuInS2 films was generally good. The CuInS2 films with a thickness of below 2 μm showed only one layer and good adhesion. On the other hand, the CuInS2 films with a thickness of more than 3 μm were formed with several layers, and were easily peeled off during deposition. The band gap value of CuInS2 samples was around 1.3 eV. The performance of the best cell obtained was Voc = 0.37 V, Jsc = 11.2 mA/cm2, FF = 0.35, and had an efficiency = 1.7%. For large size solar cells (2 × 2 cm2), the effect of In2S3 film thickness on the cell performance was significant. In order to characterize the spray-deposited CuInS2 films, the results of EPMA, XRD, XPS, and UV–vis absorption spectra have been discussed.