| Abstract: |
Up‑conversion (UC) phosphors that can sustain high luminous efficiency at elevated temperatures are pivotal for next‑generation, high‑brightness display and projection systems that operate under intense photoexcitation and thermally stressful conditions. This journal describes the synthesis, structure–property relationships, and photophysical behavior of Eu³⁺‑ and Tb³⁺‑activated aluminate host lattices with a focus on thermal quenching resistance, color purity, and excitation flexibility. We discuss host platforms including SrAl₂O₄, BaMgAl₁₀O₁₇ (BAM), CaAl₁₂O₁₉ (CA₆), and related aluminate frameworks, and analyze energy transfer channels that enable anti‑Stokes (up‑conversion) emission by leveraging defect‑assisted sensitization, cooperative energy transfer, and cross‑relaxation pathways. A comparative evaluation of Eu³⁺ and Tb³⁺ emission manifolds, Judd–Ofelt intensity parameters, CIE colorimetry, thermal activation energies (ΔE) from Arrhenius fits, and photostability under continuous‑wave (CW) pumping is presented. Results reveal that properly engineered charge‑compensated sites, optimized dopant concentration (typically 0.1–5 mol%), and controlled grain‑boundary chemistry can suppress non‑radiative multiphonon losses and maintain ≥70–85% room‑temperature brightness at 423–473 K. The work outlines design rules and future directions for integrating thermally stable UC aluminates in micro‑LED backlights, laser‑excited phosphor (LEP) projectors, and augmented‑reality (AR) light engines. |
