We reported in this study that a chelating agent, tartaric acid, can contribute to the formation of pure phase during the preparation of the SrTiO3:Pr3+ nanoparticles by a simple sol-gel method. The effects of the tartaric acid concentration, annealing temperature and Al3+ ion doping concentration on the microstructure and photoluminescence of the SrTiO3:Pr3+ nanoparticles were investigated in detail. It was found that even a small amount of tartaric acid could lead to the formation of pure phase SrTiO3, while the highest red emission of Pr3+ ions happened at a molar ratio 2:1 of tartaric acid to the metal ions Sr2+ and Ti4+, an Al3+ ion doping concentration of 2%, and an annealing temperature of 1000 degrees C. (C) 2010 Elsevier B.V. All rights resented.