Luminescent materials show wide-ranging application prospects in light-emitting devices,^{1 – 4} anti-counterfeiting,^5,6 biological imaging,^7,8 and optical information storage.⁹ However, the emission intensity of most luminescent materials is evidently reduced under the temperature range of 373 to 473 K compared to the initial state, which greatly limits their applications under high temperatures up to 473 K. The emission loss with increasing temperature is known as the thermal quenching (TQ) effect,^{10 – 12} one of the greatest obstacles to extend the commercial applications of existing materials.^{13 – 15} The TQ results in significant increase of non-radiation distribution of excited state electrons of luminescent ions. Therefore, it is urgent to explore anti-TQ luminescent materials from theoretical principles as well as rational design, which could show stable or enhanced emission with increasing temperature up to 473 K.

To obtain a deeper understand of the energy transfer mechanism between Ce³⁺ and Tb³⁺ ions in the aluminum garnet hosts, (Ce, Tb, Gd)₃Ga₂Al₃O₁₂ (GGAG:Ce, Tb) single crystals grown by the optical floating zone (OFZ) method were investigated systematically in a wide range of Tb³⁺ doping concentration (1–66 at.%). Among those, crystal with 7 at.% Tb reached a single garnet phase while the crystals with other Tb³⁺ concentrations are mixed phases of garnet and perovskite. Obvious Ce and Ga loss can be observed by an energy dispersive X-ray spectroscope (EDS) technology. The absorption bands belonging to both Ce³⁺ and Tb³⁺ ions can be observed in all crystals. Photoluminescence (PL) spectra show the presence of an efficient energy transfer from the Tb³⁺ to Ce³⁺ and the gradually quenching effect with increasing of Tb³⁺ concentration. GGAG: 1% Ce³⁺, 7% Tb³⁺ crystal was found to possess the highest PL intensity under excitation of 450 nm. The maximum light yield (LY) reaches 18,941 pho/MeV. The improved luminescent and scintillation characteristics indicate that the cation engineering of Tb³⁺ can optimize the photoconversion performance of GGAG:Ce.

Bi³⁺, Eu³⁺ and Tb³⁺ triple-doped white light emitting phosphors Ca₃ZrSi₂O₉:Eu³⁺,Bi³⁺,Tb³⁺ were successfully synthesized. In Bi³⁺ and Eu³⁺ co-doped phosphors Ca_2.83-yZrSi₂O₉:0.17Eu³⁺,yBi³⁺, the blue light from Bi³⁺ ions and red light from Eu³⁺ ions are simultaneously observed. Energy transfer exists from Bi³⁺ to Eu³⁺ ions, and the energy transfer efficiency is 19.58% in phosphor Ca_2.68ZrSi₂O₉:0.17Eu³⁺,0.15Bi³⁺.The CIE chromaticity coordinates of Bi³⁺ and Eu³⁺ co-doped phosphors, Ca_2.83-yZrSi₂O₉:0.17Eu³⁺,yBi³⁺, are just located in the orange and pink region. White light emitting was finally obtained in Eu³⁺, Bi³⁺, Tb³⁺ triply doped phosphors Ca_2.74-zZrSi₂O₉:0.17Eu³⁺,0.09Bi³⁺,zTb³⁺, through further doping green light emitting Tb³⁺ ions (⁵D_3,4 - ⁷F_J’ transitions). Energy transfer also exists from Bi³⁺ to Tb³⁺ ions, and this energy transfer efficiency is 11.95% in phosphor Ca_2.61ZrSi₂O₉:0.17Eu³⁺,0.09Bi³⁺,0.13Tb³⁺. The CIE chromaticity coordinates are always in the white light region from 25 °C to 275 °C for the triply doped phosphor Ca_2.24ZrSi₂O₉:0.17Eu³⁺,0.09Bi³⁺,0.50Tb³⁺.

As laser lighting advances toward kilowatt-level power, the thermal stability of phosphors has become a critical bottleneck limiting performance enhancement. To address the issue of luminescence degradation of YAG:Ce phosphors caused by temperature rise under laser irradiation, we introduced highly thermally conductive AlN into the YAG:Ce matrix, and successfully prepared AlN-YAG:Ce composite phosphor ceramics by powder-embedding nitrogen atmosphere sintering. The incorporation of AlN enhances lumen efficiency through increased scattering effects while improving thermal robustness via its inherent high thermal conductivity. The ceramic sample containing 50 vol.% AlN exhibits luminescence intensity comparable to that of YAG:Ce, yet its thermal conductivity is approximately three times higher, reaching 27.2 W·m^-1·K^-1. A high lumen efficiency of 200.1 lm·W^-1 and a suitable correlated color temperature of 4608 K are achieved by the ceramics with 10 vol.% AlN under 1.3 W·mm^-2 blue laser diode excitation. Moreover, a laser illumination prototype device incorporating ceramic samples containing 10 vol.% AlN and a 10 W blue laser was constructed, emitting white light with an illumination range exceeding 500 m, demonstrating potential applications in laser-driven lighting.

Ce³⁺, Pr³⁺ co-doped Lu₃Al₅O₁₂ (Ce, Pr:LuAG) single crystals and ceramics were prepared using the optical floating zone (OFZ) and reactive vacuum sintering methods, respectively. The microstructure, photo- (λ_ex = 450 nm), and radio-luminescence (under X-ray excitation) performance, as well as scintillation light yield (LY, under γ-ray, ¹³⁷Cs source) of both materials, were investigated and compared. Ce, Pr:LuAG ceramics had an in-line transmittance of approximately 20% in the visible light range, while the analogous crystals were more transparent (~65%). The X-ray excited luminescent (XEL) spectra showed the characteristic Ce ³⁺ and Pr³⁺ emissions located at 310 nm, 380 nm, and 510 nm. The highest LY of the Ce, Pr:LuAG ceramics reached 34,112 pho/MeV at 2 μs time gate, which is higher than that of a single crystal. The ratio of LY values (LY2/LY0.75) between shaping times of 0.75 μs and 2 μs indicated a faster scintillation decay of ceramics regarding single crystals. It was ascribed to the lower effective concentration of luminescent activators in single crystals because of the coefficient segregation effect.