Cu2ZnSn(S,Se)4 thin films preparation by using ammonium polysulfoselenide-based ink

In this work, Cu2ZnSn(Se,S)4 (CZTSSe) thin films were deposited by using ammonium polysulfoselenide-based ink through ultrasonic spray pyrolysis (USP) process. Thermogravimetric analysis (TGA) reveals that deposition and pre-annealing with appropriate temperature were necessary to be implemented to evaporate the excess S and retain the Se for the precursor thin films. The CZTSSe thin films were obtained by annealing in nitrogen atmosphere without extra Se source. X-ray diffraction (XRD), Raman, energy dispersive X-ray spectroscopy (EDS) detection and band gap estimation indicate that the ratios of S/(S + Se) for the prepared films can be modulated by adjusting the Se concentration of the ink. As the Se concentration of the adopted ink increased from 0.025 to 0.125 M, the ratios of S/(S + Se) for the prepared films decreased from 0.88 to 0.39, and the band gap shrunk from 1.43 to 1.16 eV.