Afterglow enhancement with In³⁺ codoping in CaTiO₃: Pr³⁺ red phosphor

CaTiO₃:Pr³⁺ phosphor with a single red emission peak of around 613nm was co-doped with In³⁺ to charge compensate in the lattice sites where a trivalent ion Pr³⁺ substitutes a divalent Ca²⁺ ion. This phosphor was prepared via the solid state reaction process. The concentration of In³⁺ was varied from 0.05 to 0.3mol% and it was found that the In³⁺ incorporation enhanced the intensity of the red emission and the afterglow decay time of the CaTiO₃:Pr³⁺ phosphor considerably. It is most likely that the incorporated In³⁺ charge compensators enhanced the luminescence intensity of the phosphor by neutralizing the additional positive charge generated by the Pr³⁺ ions when substituting in the Ca²⁺ ions site. The orthorhombic CaTiO₃ phase was identified by X-ray diffraction. Scanning electron microscopy images showed agglomerated particles with different shapes and sizes. A single red emission of Pr³⁺ of around 613nm and phosphorescence decay time of 6min were measured using photoluminescence (PL) spectroscopy and afterglow measurements, respectively. Diffuse reflectance spectroscopy was used to determine the absorbing centres of the phosphor.