Gas-solid reaction for: In situ deposition of Cu3SbS4 on a mesoporous TiO2 film

Abstract

Herein, a novel, facile, in situ gas-solid reaction method has been successfully employed for the deposition of famatinite (Cu3SbS4) semiconductor on a mesosporous TiO2 film, where precursors CuCl2 and SbCl3 were first solution-coated on a TiO2 substrate, followed by reaction with H2S gas and further thermal annealing. Various precursor ratios, temperatures and heating atmospheres have been examined for the deposition. The phase-pure Cu3SbS4 has been obtained by coating a mixed solution of CuCl2 and SbCl3 at a molar ratio of 2.5:1, and annealing at 300 °C for 10 min in an H2S atmosphere. The deposited Cu3SbS4 was uniformly distributed on the entire porous TiO2 film with crystal grain sizes of about 3-4 nm. X-ray photoelectron spectroscopy (XPS) analysis revealed valence states of the synthetic samples for Cu+, Sb5+ and S2-, verifying phase-pure Cu3SbS4. The spectral absorption of the film ranges from 400 nm to 1000 nm with a band gap of ∼1.24 eV. The Cu3SbS4 film shows good and stable photoresponse performance, indicating its high potential as photovoltaic absorber.