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

Orange-yellow luminescent Y 2- x Sr 1- y Al 4 SiO 12 : x Ce 3+ , y Mn 2+ ( x  = 0.04–0.06, y  = 0.1–0.6, abbreviated as YSAS: x Ce 3+ , y Mn 2+ ) 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  e V and YSAS is 4.874  e V. The Rietveld refinement of the XRD data indicates that Ce 3+ mainly replaces the Y 3+ sites, while Mn 2+ selectively occupies. The Gaussian peaks of the fluorescence spectrum prove that Mn 2+ occupies two luminescent centers, which are further determined by Van Uitert's empirical formula. The doping of Ce 3+ /Mn 2+ units can effectively enhance the structural rigidity of the YAG host and promote the red-shift of the emission peak position of Mn 2+ . The fluorescence decay kinetics test proves that Ce 3+ can transfer energy to Mn 2+ , 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.