Photoelectrochemical properties of AgInS2 thin films prepared using electrodeposition

Ternary silver–indium–sulfide 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 AgInS2 phase. The thickness, direct band gap, and indirect band gap of the films were in the ranges 209–1021 nm, 1.82–1.85 eV, and 1.44–1.51 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 4.2×1019–9.5×1019 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 K2SO3 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.