Synthesis and optimized sulfurization time of Cu₂SnS₃ thin films obtained from stacked metallic precursors for solar cell application

Cu₂SnS₃ (CTS) thin films were prepared by sulfurization of stacked metallic precursors deposited from radio-frequency magnetron sputtering. The effect of sulfurization time on the properties of CTS thin films and solar cells was studied. Energy dispersive X-ray results reveal that the elemental distribution becomes more homogenous with the increase of sulfurization time. X-ray diffraction, Raman spectra and X-ray photoelectron spectroscopy indicate that the film obtained at optimized sulfurization time (i.e. 20 min) has a better crystalline quality with oxidation states of Cu⁺, Sn⁴⁺ and S^2-. The solar cells fabricated with the CTS thin film sulfurized at 20 min has the efficiency up to 0.20% with V_oc=197 mV, J_sc=3.60 mA/cm² and FF=26.1%.