Ionic selective occupation, lattice modulation and photoluminescence properties of garnet typed orange-yellow phosphors for white-light-emitting diodes

Orange-yellow luminescent Y2-xSr1-yAl4SiO12: xCe3+, yMn2+ (x = 0.04-0.06, y = 0.1-0.6, abbreviated as YSAS: xCe3+, yMn2+) phosphors with garnet structure were prepared by the high temperature solid-phase method. The matrix energy band is calculated by DFT, where YAG is 4.535 eV and YSAS is 4.874 eV. The Rietveld refinement of the XRD data indicates that Ce3+ mainly replaces the Y3+ sites, while Mn2+ selectively occupies. The Gaussian peaks of the fluorescence spectrum prove that Mn2+ occupies two luminescent centers, which are further determined by Van Uitert's empirical formula. The doping of Ce3+/Mn2+ units can effectively enhance the structural rigidity of the YAG host and promote the red-shift of the emission peak position of Mn2+. The fluo-rescence decay kinetics test proves that Ce3+ can transfer energy to Mn2+, and the transfer efficiency reaches 72.08% at y = 0.5. The thermal stability test of the phosphor shows the luminous intensity at 473 K still maintains 86% of the room temperature. The phosphor prepared in this experiment was combined with a blue light chip to make a w-LED device, and the performance showed Ra = 86.1, CCT = 5168 K. The above results show that the emission color of the garnet structure can be tuned by energy transfer, which is attractive for future applications.

Automated summary

Orange-yellow luminescent Y2-xSr1-yAl4SiO12: xCe3+, yMn2+ (x = 0.04-0.06, y = 0.1-0.6, abbreviated as YSAS: xCe3+, yMn2+) phosphors with garnet structure were prepared by the high temperature solid-phase method. The doping of Ce3+/Mn2+ units can enhance the structural rigidity of the YAG host and promote the red-shift of the emission peak position of Mn2+. The thermal stability test of the phosphor showed that the luminous intensity at 473 K still maintained 86% of the room temperature.