New phase-construction phosphors ceramics for warm-white solid-state lighting: Orange-yellow-emitting (Lu,Gd)3(Sc,Al)5O12: Ce3+

Abstract

Phosphor-converted white light-emitting diodes (pc-wLEDs) and phosphor-converted white laser diodes (pc-wLDs) are extensively utilized in lighting applications, with their quality and reliability heavily dependent on color converters. Recent progress in all-inorganic color converters, particularly phosphor ceramics (PCs), have markedly enhanced performance. However, due to the difficulty of managing emissive components, achieving warm white light with substantial red emission still remains challenging. In this work, a series of pure-phase Ce³⁺-activated garnet-structured solid-solution PCs, (Lu,Gd)₃(Sc,Al)₅O₁₂: Ce (LGSAG: Ce), were fabricated using vacuum sintering technology for the first time. Through systematic analysis, it can be revealed that the addition of Gd³⁺ leads to a red shift in emission through changes in crystal-field splitting, whereas the inclusion of Sc³⁺ primarily focuses on improving the microstructure of the developed PCs. Particularly, the pc-wLED constructed from typical LGSAG: Ce PC generated significantly warmer light with a correlated color temperature (CCT) of 2916 K, compared to the 9557 K from LuAG: Ce PC. Meanwhile, under 40.0 W (15.7 W/mm²) blue laser excitation, the maximum luminous flux and luminescence efficiency of one typical LGSAG: Ce PG are 1172 lm and 29.3 lm/W, respectively. Therefore, the developed LGSAG: Ce PCs can show notable potential as color converters for future high-power warm-white solid-state lighting applications.