Effect of Copper Content on Structural, Morphological, Optical and Photoelectrochemical Properties of SILAR Deposited Cu3SnS4 Thin Films

In this study, Cu3SnS4 (CTS) thin films were deposited by successive ionic layer adsorption and reaction (SILAR) method at room temperature. X-ray diffraction, Raman spectroscopy, scanning electronic microscopy, Ultra-violent-visible-near infrared absorbance spectroscopy and photoelectrochemical analyses were used to follow the evolution of the investigated properties. The results outlined a tetragonal (I-42m) CTS phase and a secondary copper sulfide (Cu2-xS) and Cu4SnS4 phase, and their ratio strongly depends on the copper concentration. No traces of secondary phases of tin sulfide is found while CTS was obtained. It was found that the application of additional Cu concentration increases from 0.025 to 0.075M, enhances the grain growth in size and induces significant improvement of CTS crystallinity and power conversion efficiency. The optical band gap ranges between 1.90, 1.21 and 1.07eV depending on the copper concentration 0.025, 0.050 and 0.075 M, respectively. This study shows promising results, as a developing photovoltaic applications, using SILAR CTS as absorber.