Preparation of chemical bath synthesized ternary Ag-Sn-S thin films as the photoelectrodes in photoelectrochemical cell

In this study, ternary Ag-Sn-S thin films are grown on glass and indium tin-oxide coated glass substrates using chemical bath deposition. The structural, optical, electrical, and photoelectrochemical properties of the Ag-Sn-S thin films on substrates are investigated as a function of the [Ag]/[Ag + Sn] molar ratio in the precursor solution. X-ray diffraction patterns show that the samples change from Ag2S/Ag8SnS6, Ag8SnS6, Ag8SnS6/Ag4Sn3S8, and Ag8SnS6/Ag2S/SnS mixing phases with a decrease in the [Ag]/[Ag + Sn] molar ratio in the precursor solution. With a decrease in the [Ag]/[Ag + Sn] molar ratio in the precursor solution, the (0 2 2) diffraction peak of samples shifts to lower angles. A pure orthorhombic Ag8SnS6 phase is obtained in the samples prepared with [Ag]/[Ag + Sn] molar ratios in the precursor solution of 0.5-0.6. The energy band gaps of the samples obtained from transmittance and reflectance spectra are in the range of 1.17-1.48 eV. The carrier concentrations and mobilities of the samples are in the ranges of 2.5 x 10(12)-3 x 10(14) cm(-3) and 14.02-23.05 cm(2)/V s, respectively. The maximum photoelectrochemical performance of the samples in aqueous solution containing SO32- and S2- ions is 1.13 mA/cm(2) at an external potential of 0 V vs. an Ag/AgCI reference electrode under 100 mW/cm(2) light illumination from a Xe lamp source. Crown Copyright (C) 2014 Published by Elsevier B.V. All rights reserved.