In5CuS8

In₅CuS₈ is a quaternary sulfide semiconductor compound belonging to the metal chalcogenide family, combining indium, copper, and sulfur in a structured crystalline lattice. This material is primarily of research interest for photovoltaic and optoelectronic applications, where its band gap and electronic properties position it as a potential absorber layer or window material in thin-film solar cells and photodetectors. Compared to more established semiconductors like CdTe or CIGS, In₅CuS₈ offers the advantage of using abundant, non-toxic elements while potentially delivering competitive optical and transport properties, though it remains largely in the development phase with limited commercial deployment.