The size dependent of temperature and precursor concentration on the synthesis of hexadecylamine capped Ag2Se nanoparticles via the colloidal route were studied using the combination of optical and structural analysis. The as-prepared Ag2Se nanoparticles showed the quantum confinement with all the obtained absorption band edges blue-shifted from the bulk and their corresponding emission maxima displaying a red-shift from band edges characterised by UV-vis absorption and photoluminescence spectroscopy. The particle sizes were obtained from transmission electron microscopy analysis. The increase in precursor concentration resulted in a decrease in nanoparticle sizes. The increase in reaction temperature showed an increase in the nanoparticle sizes, when the critical temperature at 160 degrees C was reached, the nanoparticle sizes decreased. (C) 2013 Elsevier Ltd. All rights reserved.