Photoelectrochemical properties of AgInS₂ thin films prepared using electrodeposition

Ternary silverindiumsulfide samples were deposited on fluorine-doped tin oxide (FTO) coated glass substrates using a one-step electrodeposition method. A new procedure for the deposition of AgInS₂ samples is reported. The effect of the [Ag]/[In] molar ratio in solution bath on the structural, morphological, and photoelectrochemical properties of samples was examined. X-ray diffraction patterns of samples show that the films are the AgInS ₂ phase. The thickness, direct band gap, and indirect band gap of the films were in the ranges 2091021 nm, 1.821.85 eV, and 1.441.51 eV, respectively. The carrier densities and flat-band potentials of films obtained from Mott-Schottky and open-circuit potential measurements were in the ranges of 4.2×10¹⁹9.5×10¹⁹ cm^-3 and -0.736 to -0.946 V vs. the normal hydrogen electrode (NHE), respectively. It was found that the samples with molar ratio [Ag]/[In]=0.8 in solution bath had a maximum photocurrent density of 9.28 mA/cm² with an applied bias of 1.0 V vs. an Ag/AgCl electrode in contact with electrolyte containing 0.25 M K ₂SO₃ and 0.35 M Na₂S. The results show that high-quality AgInS₂ films can be deposited on FTO-coated glass substrates for photoelectrochemical (PEC) applications.