Structural and optical properties of Cu2ZnSnS4 thin film absorbers from ZnS and Cu3SnS4 nanoparticle precursors

Cu2ZnSnS4 (CZTS) has been considered as an alternative absorber layer to Cu(In,Ga)Se2 due to its earth abundant and environmentally friendly constituents, optimal direct band gap of 1.4–1.6 eV and high absorption coefficient in the visible range. In this work, we propose a solution-based chemical route for the preparation of CZTS thin film absorbers by spin coating of the precursor inks composed of Cu3SnS4 and ZnS NPs and annealing in Ar/H2S atmosphere. X-ray diffraction and Raman spectroscopy were used to characterize the structural properties. The chemical composition was determined by energy dispersive X-ray spectroscopy. Optical properties of the CZTS thin film absorbers were studied by transmission, reflection and photoluminescence spectroscopy.