Single-step Electrodeposition of 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 ºC 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 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 FE-SEM micrographs. The optical band gap of CZTS thin-films was found almost remains constant between 1.50 eV to 1.60 eV as the concentration of the complexing agent increased from 100 mM to 400 mM. 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.
