Tb ³⁺ → Eu ³⁺ energy transfer unlocks efficient red emission and thermal stability of NaY _0.1 Gd _0.9 (WO ₄ ) ₂ phosphors

In this paper, [Formula: see text]: x%[Formula: see text] (x= 10, 20, 30, 40, 50) and [Formula: see text]: 40%[Formula: see text], y%[Formula: see text] (y= 0.5, 1, 3, 5, 7, 10, 20) series phosphors were prepared by high temperature solid state reaction. The effects of [Formula: see text] and [Formula: see text] co-doping on the phase structure and luminescent properties of [Formula: see text] (NYGW) phosphors were analyzed by XRD, PL and absorption spectra. XRD patterns and Rietveld refinement results show that these phosphors crystallize in a tetragonal scheelite-type structure with high phase purity. In addition, the optimum [Formula: see text] doping concentration ratio was obtained by analyzing the PL spectra, and the wavelength emission of 589 nm and 614 nm was realized. In addition, the CIE color coordinates of NYGW: 40%[Formula: see text], 1%[Formula: see text] were obtained, and the luminescent properties of the phosphor were analyzed. The average fluorescence lifetime of NYGW: 40%[Formula: see text], 1%[Formula: see text] is 1.404 ms after fitting calculation. The band gaps of NYGW, NYGW: 40%[Formula: see text] and NYGW: 40%[Formula: see text], 1%[Formula: see text] are calculated by first principles calculation. Finally, the optimized composition [Formula: see text]: 40%[Formula: see text], 1%[Formula: see text] exhibits excellent red emission and thermal stability, indicating its potential application in WLEDs.