Thermally-stable novel single-phase phosphor of Ca2InTaO6:Dy3+ for NUV-excited white LEDs

Abstract

The work focuses on the utilization of the conventional solid-state sintering procedure to synthesize white phosphors Ca2InTaO6:xDy3+ (0.02 ≤ x ≤ 0.12). Utilizing X-ray diffraction, the phase structure of samples was examined, and the crystal structure was refined using the Rietveld method. A scanning electron microscope was used to analyze the microstructure of sample. First-principles calculations confirm that the indirect bandgap of Ca2InTaO6 is 3.786 eV. The luminous properties and energy transfer mechanism of Ca2InTaO6:xDy3+ were studied using photoluminescence spectroscopy. The 4F9/2 → 6H13/2 transition of Dy3+ ions is responsible for the greatest emission peak, which was measured at 575 nm. According to research, the lifespan falls as the concentration of Dy3+ doping amount rises because of frequent interaction and energy transfer between Dy3+ ions. The correlated color temperature of the W-LEDs packaged with Ca2InTaO6:0.08Dy3+ is 4677 K and CIE 1931 chromaticity coordinates are (0.3578, 0.3831). Meantime, the phosphor also shows outstanding temperature stability property, which maintains 83.8% of its initial emission intensity at 450 K (activation energy of 0.1467 eV). The W-LEDs retain their performance for 100 min when powered at 3.4 V voltage and 600 mA current, demonstrating the packed W-LEDs' sustained operation at high temperatures.