Blue photons excited highly chromatic red light emitting K3La(PO4)2:Pr3+ phosphors for white light emitting diodes

Highly chromatic blue photons excited red emitting K3La(PO4)(2):Pr3+ (0-1.8 mol%) phosphors were synthesized by solution combustion method. The resulted phosphors showed peanut like morphology and had a monoclinic phase with space group P2(1)/m. The photoluminescence studies disclosed that the phosphor emits red light due to the D-1(2) -> H- 3(4) and D-1(2 )-> H-3(5) transition of the Pr3+ ions under blue photons excitation. The optimal concentration for the Pr3+ ions were optimized to be 1.2 mol% after which concentration quenching occurred. Dipole-dipole interaction among the dopant ions was found to be responsible for the concentration quenching. X-ray photoelectron spectroscopy results depicted that Pr was present in the (+3) valance state in the phosphor. The photometric results suggest that the phosphor with a high color purity similar to 97.8% and enough quantum yield similar to 27% could be an eventual choice as the red component for white light emitting diodes.