PbS thin films with deposition times of 100, 115, 130 and 145 min were prepared by chemical bath deposition method at room temperature. Their crystal structures were characterized by X-ray diffraction. All films were polycrystalline with a cubic rock salt structure. The morphological properties of the films were investigated by scanning electron microscopy. The optical properties of the films were studied using the absorbance, transmittance and reflectance spectra. The optical band gap of the films decreased from 2.65 eV to 2.50 eV with increasing deposition time. The optical parameters of the materials such as refractive index, extinction coefficient and dielectric constants Were also determined. The electrical conductivity of the PbS film increased from 1.791 x 10(-6) to 1.655 x 10(-3) (Omega cm)(-1) with increasing deposition time. Thermoluminescence intensity of the films was measured after irradiating the films with a beta source for 15 min at room temperature and the kinetic parameters were obtained by using the computer glow curve deconvolution method. (C) 2013 Elsevier B.V. All rights reserved.