In this study, Ag-In-S ternary system semiconductor materials in thin film form were deposited on indium-tin-oxide coated glass substrates with various molar ratios of two complex agents in reaction solutions using chemical bath deposition. The effects of complex agents on the structural, electric, and optical properties of the Ag-In-S ternary system semiconductor films were investigated. The crystal phases of samples were polycrystalline AgInuSv (5 < u < 8.8, 8 < v < 13.3, v/u = 1.6). With an increase in molar ratio of triethanolamine complex agent in the reaction solution, the peaks of samples shifted to low angles, which indicates that the crystal phase of samples approached AgIn5S8. The thicknesses, direct and indirect energy band gaps of samples varied from 205 nm to 1070 nm, 1.77 eV to 1.87 eV and 1.44 eV to 1.61 eV, respectively, depending on the molar ratios of complex agents in the reaction solution. The flat band potentials of these samples lie in the range of -0.391 V to -0.098 V referred to the standard hydrogen electrode (SHE). The maximum photocurrent density of samples reached 5.2 mA cm(-2) at an external potential of +1.5 V vs. a Pt electrode in contact with K2SO3 and Na2S aqueous electrolyte under illumination using a 300W Xe lamp system with a light intensity set at 100 MW cm(-2). Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.