Enhanced red phosphorescence in nanosized CaTiO₃:Pr³⁺ phosphors

The red photoluminescence and phosphorescence originating from ¹D₂-³H₄ transition of Pr ³⁺ in CaTiO₃ nanoparticles are studied as a function of Pr³⁺ concentrations. The nanophosphors exhibit both longer persistence time of 30 min and higher quenching concentration of 0.4 mol % than the bulk (10 min and 0.1 mol %). The initial phosphorescence in the nanophosphor is an order of magnitude stronger than that in the bulk at the corresponding quenching concentrations. Phosphorescence decay patterns and diffused reflectance spectra before and after ultraviolet exposure indicate the existence of more traps contributing to phosphorescence in the nanoparticles.