Optoelectronic applications of chemical bath deposited Cu₂SnS₃ (CTS) thin films

Cu₂SnS₃ (CTS) thin film (TF) is deposited by a low-cost chemical bath deposition method. The wurtzite unit cell structure of deposited CTS TF is confirmed by X-ray diffraction analysis. The atomic force microscopy shows uniform and defect-free deposition of CTS TF. The direct optical bandgap of 1.48 eV is confirmed by diffuse reflectance spectroscopy. The deposited CTS TF is studied for photo-response properties. Responsivity, sensitivity, and detectivity of 5.73 mW A^-1, 114.27 × 10^-3, and 6.39 × 10¹² Jones are obtained respectively. In another application, the first ever heterojunction and a photo-electrochemical (PEC) type CTS-TiO₂ configuration within a single solar cell device is carried out. This CTS-TiO₂ based combined solar cell delivered a current density of 0.05 mA cm^-2, open circuit voltage of 0.47 V, efficiency of 0.014%, and fill factor of 0.63. Theoretical predictions of solar cell parameters for the CTS-CdX (X = S, Se) heterojunction device are carried out using SCAPS-1D simulation. Temperature-dependent thickness variations at 273, 298, 310, and 373 K are carried out to evaluate the device performance. The obtained results are discussed in detail.