Silver sulphide (Ag(2)S) thin films were grown on the surface of silver films (Ag) deposited on glass substrate by using a simple chemical sulphurization method. According to X-ray diffraction analysis, the Ag(2)S thin films display low intensity peaks at 34.48 degrees, 36.56 degrees, and 44.28 degrees, corresponding to diffraction from (100), (112) and (103) planes of the acanthite phase (monoclinic). A model of the type Ag(2)S/Ag/glass was deduced from spectroscopic ellipsometric measurements. Also, the optical constants (n, k) of the system were determined. Furthermore, the optical properties as solar selective absorber for collector applications were assessed. The optical reflectance of the Ag(2)S/Ag thin film systems exhibits the expected behavior for an ideal selective absorber, showing a low reflectance in the wavelength range below 2 mu m and a high reflectance for wavelengths higher than that value. An absorptance about 70% and an emittance about 3% or less were calculated for several samples. (C) 2009 Elsevier B.V. All rights reserved.