A potential red-emitting phosphor Na2.5Zr2Si1.5P1.5O12: Eu3+ for WLEDs with excellent thermal stability, color purity and high quantum efficiency

Developing and researching high quantum efficiency red phosphor with small thermal quenching performance was vital for white light-emitting diodes (WLEDs). Herein, a series of novel red emitters Na2.5Zr2-xSi1.5P1.5O12: xEu3+ (NZSPO: Eu3+, 0 ≤ x ≤ 0.07) were prepared and studied. The detailed crystal structure, morphology features and coordinated information of the cations were studied by X-ray diffraction, Rietveld refinement and SEM. The spectral analysis results showed that NZSPO: Eu3+ phosphor could exhibit excellent CIE chromaticity coordinate and high color purity. Excitingly, the internal quantum efficiency of the optimized NZSPO: 0.05Eu3+ could reach 72.14%. And the intensity could still keep 93.3% compared with the initial emission intensity at 140 °C. The concentration quenching mechanism was investigated and then demonstrated to be dominated by the dipole-dipole interaction. In addition, the lifetime of NZSPO: Eu3+ decreased with the increase of Eu3+ concentration, and the average decay time was 1.85 ms. The CCT of the white light emitted by the packaged WLED was 5337 K and the CIE coordinates could reach (0.3357, 0.3338), which was on the verge of the standard white coordinates (0.33, 0.33). All the results showed that NZSPO: Eu3+ could be served as a prospective red light-emitting phosphor for WLEDs.