Photoluminescence and energy storage traps in CaTiO3:Pr3+

Red-emitting CaTiO3:Pr3+ phosphors are fabricated using a solid state method and structurally characterized by X-ray diffraction and field emission scanning electron microscopy. The optical properties are investigated using photoluminescence emission, excitation, photoluminescence decay curves, diffused reflectance and thermoluminescence spectra, and persistent phosphorescence decay curves. The optimal fabrication temperatures for photoluminescence and persistent phosphorescence are found at 1200-1300 degrees C for photoluminescence and 1400 degrees C for persistent phosphorescence. The energy storage traps for persistent phosphorescence in the system are analyzed based on the dependence of photoluminescence and persistent phosphorescence on sintering temperature. The distribution of energy storage traps is further characterized by thermoluminescence spectra and the parameters of the traps are calculated. Oxygen vacancies as the main trapping centers play the key role for persistent phosphorescence in CaTiO3:Pr3+. (C) 2010 Elsevier Ltd. All rights reserved.