Cu-Ag-In-S solid solution semiconductor films were grown on indium-tin oxide-coated glass substrates using chemical bath deposition. New procedures for the growth of Cu-Ag-In-S semiconductor films are presented. The optical, electrical, and photoelectrochemical performances of the ternary CuInS(2), AgIn(5)S(8), and their solid solutions are investigated. The X-ray diffraction patterns of samples reveal a change in the crystal phase of the samples from the tetragonal CuInS(2) to the cubic AgIn(5)S(8) phase with an increase in the [Ag/(Cu+Ag)] molar ratio in precursor solutions. The thicknesses and band gaps of the samples, determined from the surface profile measurements and transmittance spectra, are in the ranges of 841-2107 nm and 1.42-1.75 eV, respectively. The highest photoresponse was observed in the sample with [Ag/(Ag+Cu)] = 0.4 (sample (d)) under illumination with a white light intensity of Too mW/cm(2). The results show that Cu-Ag-In-S film electrodes have potential in solar to hydrogen applications. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.