A novel single-phase white-emitting garnet-structured phosphor with ultra-high luminescent thermal stability and color stability

Currently, single-phase white-emitting phosphors have garnered significant attention in the field of phosphor-converted white light-emitting diodes (pc-WLEDs). Unfortunately, poor luminescent thermal stability has severely hindered the development of phosphors for solid-state lighting. In this study, to enhance the luminescent thermal stability of phosphors, and a series of NGGGO:Dy³⁺,Tm³⁺ phosphors were successfully synthesized via the high-temperature solid-state method. The effects of different doping concentrations on the crystal structure, luminescent spectrum, and thermal stability of the phosphors were thoroughly investigated. X-ray diffraction analysis revealed that all the phosphors maintained a garnet structure without the formation of any impurity phases. Photoluminescence spectra demonstrated that under excitation at 353 nm, the yellow emission of Dy³⁺ and the blue emission of Tm³⁺ achieved effective spectral complementarity, yielding white light emission with CIE coordinates of (0.329, 0.329). More importantly, the phosphor exhibited exceptional luminescent thermal stability, maintaining 96.21 % of its luminescent intensity at room temperature even at high temperatures (475 K). This study provided new insights for the development of efficient and thermally stable single-phase white-emitting phosphors, potentially advancing the technology of white LED lighting.