ZrO2:Mn, Er nanocrystals have been prepared at different temperatures ranging from 400degreesC to 600degreesC by a coprecipitation method. The crystallinity of the samples was characterized by the X-ray diffraction (XRD) patterns and a transmission electron microscopy micrograph. The luminescent properties of the co-doped sample as a function of the doping concentration of Er3+ and the heat-treated temperature have also been investigated. For all the doped samples, a red emission band centered at 638 nm was observed corresponding to the a(4)Gamma-S-6 transition of Mn2+. Due to the energy transfer between Er3+ and Mn2+, the relative intensity of the emission varies greatly with changing Er3+ concentrations. The quenching of the PL intensity with increase in temperature is assigned to the decrease of residual chlorine in the sample. (C) 2003 Elsevier B.V. All rights reserved.