Tailored efficient energy transfer Tb3+, Eu3+ activated/co-activated LiAl(PO3)4 phosphor by substitution of alkali metals: the effect of charge compensation

Abstract

Phosphites are the new emerging candidates in the field of luminescence in the modern era. In the present investigation, Tb³⁺/Eu³⁺ activated/co-activated LiAl(PO₃)₄ phosphor was prepared by a wet chemical method, and the effect of R⁺ (Na⁺, K⁺) ions on photoluminescence (PL) properties of these phosphors are investigated. Phase identification and crystal structure of the prepared phosphor were determined using XRD and Rietveld refinement, respectively. Morphological study and elemental analysis of the proposed phosphor with elemental analysis of the sample were performed using SEM and EDS. The PL properties of the proposed phosphor showed three simultaneous emission peaks in the visible range, giving color-tunable emission. The charge compensation of Na⁺ and K⁺ ions make a significant impact on the PL intensity of Tb³⁺, Eu³⁺ co-activated LiAl(PO₃)₄ phosphors. The PL intensity of Tb³⁺, Eu³⁺ co-activated LiAl(PO₃)₄ phosphors was significantly enhanced by factors 1.2 and 1.4 when Na⁺ and K⁺ charge compensators, respectively, were introduced. To manifest the charge compensation effect of alkali metals the optimum intense sample in the co-doped sample was used. These results indicate the potential candidacy of the studied phosphor for further improvement in PL properties for application in solid-state lighting.