Enhancing Antithermal Quenching in YTa_1-xNb_xO₄:Tb³⁺ Phosphor Based on Excitation Driving and Energy Transfer

Tb³⁺-doped phosphors, serving as critical green-emitting materials for solid-state lighting, face severe reliability limitations in high-power devices due to their high-temperature thermal quenching effects. This study proposes a synergistic strategy combining excitation-driven modulation with host-activator energy transfer optimization through Ta⁵⁺/Nb⁵⁺ cosubstitution in novel Y_0.97Ta_1-xNb_xO₄:3%Tb³⁺ phosphors, achieving integrated innovation in thermal quenching suppression and dual-mode thermal response functionality. Photoluminescence measurements and density functional theory (DFT) calculations demonstrate energy transfer from [Ta/NbO₄]^3- to Tb³⁺ in the phosphors, while minor Nb⁵⁺ substitution (x = 0.005) enhances the energy transfer efficiency from the host-to-activator. Concurrently, under excitation-driven effects (λ_ex = 233 nm), the phosphor exhibits 1.75-fold luminescence enhancement at 523 K compared with 298 K. Subsequent thermal cycling tests demonstrate a 2.10-fold enhancement in maximum relative luminescence intensity by the second cycle. Innovative discoveries: the phosphor displays reversible thermally responsive luminescence with dynamic migration of International Commission on Illumination (CIE) chromaticity coordinates during heating. Two derived applications are as follows: fluorescence intensity ratio-CIE chromaticity hybrid optical thermometry model (maximum relative sensitivity is 1.25% K^-1); multiwavelength-excitation-driven dynamic anticounterfeiting system. This research provides a novel strategy for developing intelligent thermally responsive phosphors, demonstrating unique application potential in high-precision temperature sensing and high-security information encryption.