The temperature dependence of photoluminescence (PL) efficiency in fluorescent dye-doped tris(8-hydroxyquinoline) aluminum (Alq(3)) layers and blended Alq(3) layers was investigated. Results show that the PL efficiency in the fluorescent dye-doped Alq(3) layers has only weak temperature dependence, which is in contrast to the dramatic decrease of PL efficiency observed upon increasing temperature for undoped Alq(3). This phenomenon is attributed to the narrower energy bandgap of the dopant, as compared to that of Alq(3), which leads to the 'trapping' of mobile excitons on dopant molecules, hence impeding their migration by thermally activated diffusion, thereby decreasing their encounters with randomly distributed non-radiative recombination (i.e. quenching) sites. (c) 2008 Elsevier B.V. All rights reserved.