In this work, highly dispersed and near stoichiometric chalcopyrite CuInSe2 nanoparticles were successfully synthesized via a facile and rapid one-pot method. The effects of reaction temperature and reaction time on the crystal phase, morphology, element composition and the absorption spectrum of the as-synthesized CuInSe2 nanoparticles were investigated by x-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and 11V-Vis-IR spectrophotometer, respectively. The XRD patterns showed that the as-synthesized nanoparticles had pure chalcopyrite phase with the particle size in the range of 50-300 nm confirmed by FE-SEM images. The Vis-IR absorption spectra showed strong absorption in the entire visible light to near-infrared region, the estimated band gap of the as-synthesized nanoparticles matched very well with that of the bulk CuInSe2 material. All results suggested that the as-synthesized CuInSe2 nanoparticles were good light absorber layer material for thin film solar cell. (C) 2013 Elsevier B.V. All rights reserved.