Single-step Electrodeposition of Cu2ZnSnS4 (CZTS) Thin Film: Influence of Complexing Agent Concentration

Abstract

Thin films of Cu2ZnSnS4 (CZTS) thin films have been prepared on Mo-coated corning glass substrates using a single-step electrodeposition method at room temperature for different concentrations of complexing agent, trisodium citrate (Na3C6H5O7). The films were sulfurized at 550 °C for 10 min in (Ar + H2S) atmosphere. The formation of CZTS films was confirmed by X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The film deposited without the complexing agent (0 mM) shows the smallest crystallite size, non-uniform morphology, non-stoichiometric composition, and poor photoresponse. The shift in the reduction potential towards negative potential with an increase in complexing agent concentration from 0 mM to 400 mM was revealed from cyclic voltammetry (CV). The Energy dispersive X-ray spectroscopy (EDS) analysis showed the formation of CZTS films with Cu- and Sn-poor composition for the higher concentration of the complexing agent. The decrease in grain size for higher complexing agent concentration has been observed from field emission scanning electron microscope (FE-SEM) micrographs. An increase in bandgap with increased concentration of complexing agent from 100 mM to 400 mM has been evaluated from diffuse reflectance spectroscopy (DRS) analysis. Finally, preliminary results on photoelectrochemical (PEC) measurements of CZTS film photoanode were discussed. The obtained result suggests that CZTS can be a potential material for PEC applications apart from an absorber layer in solar photovoltaics.