Structural and optical properties of Cu2FeSnS4 thin film synthesized via a simple chemical method

Cu2FeSnS4 thin film, with potential as an effective photovoltaic absorber, was prepared by sulfurizing a (Cu,Sn)S/FeS-structured precursor prepared via successive ionic layer absorption and reaction combined with chemical bath deposition. X-Ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-vis-NIR absorbance measurements showed that the Cu2FeSnS4 thin film exhibits large agglomeration of rod-shaped grains, a bandgap of Eg=1.22 eV, and a high optical absorption coefficient (>104 cm−1).