Enhancement of photoluminescence properties in Na+ doped K2BaPO4F: Sm3+phosphors

In this paper, Sm3+-activated K2BaPO4F red phosphors were prepared by a traditional solid-state reaction method. The crystal structure and emission enhancement mechanism of the materials were systematically investigated. The photoluminescence intensity, chromaticity, lifetime, and fluorescence thermal stability were evaluated in detail. The emission intensity and quantum efficiency were significantly improved by the intro-duction of Na + ions. The lattice parameters of the K2BaPO4F, K2Ba0.975PO4F:0.025Sm3+, and Na-doped K2Ba0.975PO4F:0.025Sm3+ phosphors were investigated through the Rietveld refinement method. With the occupation of K+ sites by Na+ ions, the reduced volume of the unit cell increased the quantum efficiency of Sm3+ ions about 2.5 times. The present work demonstrates that the modified K2-2xNa2xBa0.975PO4F:0.025Sm3+ orange-red phosphors are expected to be used in white light-emitting diodes (w-LEDs).