Exploring the microstructural, optoelectronic properties of deposition time dependent Cu2Sn(S,Se)3 thin film synthesized by non-vacuum arrested precipitation technique

Abstract A novel chemical approach is utilized to synthesize Cu2Sn(S,Se)3 (CTSSe) thin films by non-vacuum arrested precipitation technique (APT) via controlled release of ions from complexed solution. Effect of deposition time on the microstructural and optoelectronic properties of CTSSe thin films was studied comprehensively. The optical absorption studies demonstrate a decrease in band gap energy from 1.84 to 1.62 eV as the deposition time increases. Nanocrystalline thin films with improved grain size were illustrated from XRD studies. The FESEM micrographs depict progress in surface microstructure from a bunch of nanospheres to aggregated and densely packed nanospheres. EDS spectrum confirms the stoichiometric formation of Cu2Sn(S,Se)3 thin film. While, the XPS spectrum validates Cu1+, Sn4+, S2-, Se2-valence states of the elements in CTSSe thin film. Furthermore, the photoelectrochemical cell performance of 0.3 % for bare CTSSe thin film was elucidated with cell configuration glass-FTO/CTSSe/(I-/I3-)/graphite without any post deposition treatments. Also, the lowering of charge transfer resistance from EIS measurements corroborates for improved photoconversion efficiency. Finally, synthesis of CTSSe thin films by a simple APT finds a promising approach to fabricate efficient CTSSe photocathode for photovoltaic applications.