Processing, point defects and photoluminescence of Pr-CaTiO 3 phosphors

Perovskite structured calcium titanate can be directly synthesized at room temperature. Other partial amorphous phase will have started to crystallize at 600 degrees C following the incorporation of Pr ion into the lattice. The doping mechanism is studied. The relationship between processing and point defects is found. The lattice cell expends with the annealing temperature until 900 degrees C, after that, contracts suddenly at 1000 degrees C and then tends to a constant at the temperature over 1100 degrees C. The mechanism of photoluminescence of Pr3+ doped CaTiO3 is set up. The powders have the red emission at 613 nm by the activation of UV light. The intensity of the emission increases with the annealing temperature till 1000 degrees C and then decreases, due to it has a correlation with the concentration of incorporated Pr ion. The decay time increases with the annealing temperature. The photoluminescence behavior is associated with the point defects which can be tailored by the processing of the powders, especially by the annealing temperatures.