Nanocrystalline Tm3+(5%)-doped BaTiO3 (BT-Tm) has been synthesized by the sol-gel method. The morphology, structure, and optical properties of powders and ceramics were characterized. The average grain size of the gel precursor annealed at 700 and 900 degrees C was 20 nm and 30 nm, respectively. These powders were single phase and crystallized with a cubic structure while the BT-Tm sintered ceramics were crystallized with the tetragonal BaTiO3 structure. The photoluminescence spectra showed typical transitions of Tm3+ ions and a structure consistent with the Tm3+ ions incorporation in the BaTiO3 crystalline lattice. Thermoluminescence peaks recorded at 300 degrees C (for annealed samples) or at 230 degrees C for the ceramic sample were assigned to the recombination of the Tm2+-electron traps located mainly at the surface of the nano-crystals or inside the microcrystals, respectively. (C) 2012 Elsevier B.V. All rights reserved.