Size manipulated photoluminescence and phosphorescence in CaTiO ₃:Pr³⁺ nanoparticles

Red emitting nanophosphors of CaTiO₃:Pr³⁺ with various particle sizes were prepared by sol - gel methods and structurally characterized by X-ray diffraction and field emission scanning electron microscopy. The fluorescent and phosphorescent properties of CaTiO ₃:Pr³⁺ nanoparticles as a function of particle sizes were investigated by using photoluminescence and photoluminescence excitation spectra as well as time decay patterns of fluorescence and phosphorescence. On the analysis of the longer lifetimes at 300 K as compared to that at 77 K and the appearance of maximal photoluminescence, the dependence of photoluminescence on phosphorescence is demonstrated. A very highly efficient phosphorescence recombination channel in the nanophosphor is proposed and discussed. This work provides a promising method to develop novel phosphors by manipulating the number of traps on the surface of nanophosphors through adjusting the particle size.