Cu2MnSnS4 thin films by sputtering technique for photovoltaic applications

Many efforts have been made word-wide to obtain earth-abundant variants of Cu2(In,Ga)(S,Se)4 for photovoltaic application. With the most famous Cu2ZnSnS4, Cu2MnSnS4 (CMTS) has been lately investigated thanks to the manganese’s Earth abundancy higher than zinc. [1-3] Here, we present CMTS produced by sputtering the metal’s precursors and subsequent sulphurization of the layer in argon atmosphere. A thin layer of cadmium sulphide was deposited by chemical bath deposition to obtain a p-n junction. The device was then finalized with a capping layer of intrinsic zinc oxide, a window layer of aluminum-doped zinc oxide, and an aluminum grid to collect charge effectively. Designed heat treatment on the entire device has been employed in the air atmosphere to enhance the photovoltaic performances. X-ray diffraction and µ-Raman spectroscopy have shown CMTS as the primary phase. Scanning electron microscopy images showed compact and uniform material with a thickness of about 900 nm, and through the energy dispersive X-ray analysis, we confirmed the composition of the final material. J-V measurements on the optimized devices recorded a maximum efficiency of 0.9%. The photoluminescence and external quantum efficiency data analysis identified the detrimental defects acting in working conditions, suggesting paths to improve the photovoltaic properties. [1] Le Donne et al. Frontiers in Chemistry 7 (2019) 297. [2] Marchionna et al. Journal of Alloys and Compounds 693 (2017) 95. [3] Le Donne et al. Solar Energy 149 (2017) 125.