Tm-doped Ba0.8Sr0.2TiO3 thick films were prepared by the screen-printing technique on the alumina substrate. The microstructure of the Tm-doped BST thick films was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy, respectively. All the samples showed a typical perovskite polycrystalline structure when sintered at 1260 degrees C. The substitution behavior of Tm3+ ion in BST was found to change with increasing the Tm3+ concentration. The observed Tm-related red emission reaches the maximum at 0.2 mol% Tm3+ concentration. The effects of concentration quenching on the luminescence intensity were discussed. (C) 2011 Elsevier B.V. All rights reserved.