Synthesis and Optoelectronic Properties of Quinary Wurtzite Copper-based Chalcogenide Cu ₃ MInSnS ₆ (M= Cd, Co, and Ni) Nanocrystals

Quinary wurtzite copper-based chalcogenide, Cu 3 MInSnS 6 (M= Cd, Co, Ni), nanocrystals (NCs) have been synthesized using a hot-injection method. The NCs were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and absorption spectroscopy. The NCs exhibit strong absorption across the visible spectrum with bandgaps ranging from 1.44 to 1.54 eV, ideal for thin-film solar cell applications. Photoresponse measurements demonstrate that the current under illumination is enhanced compared to the dark current in all thin-film samples fabricated from these NCs. Among the tested samples, the Cu 3 CdInSnS 6 -based film displayed the highest Ilight/Idark ratio. A prototype solar cell fabricated with Cu 3 CdInSnS 6 NCs achieved a power conversion efficiency of 0.73%. This work broadens the exploration of quinary copper-based chalcogenides for photovoltaic applications and offers insights that assist in the development of new solar cell absorbers.