Eu3+-Activated Ba2LaMoO6 Red-Emitting Phosphors for UVB/Blue-Driven Solid-State Lighting

Abstract

Thermally stable red-emitting phosphors capable of sustaining efficiency at elevated temperatures are crucial for high-power solid-state lighting. In this study, Eu³⁺-activated Ba₂LaMoO₆ phosphors were synthesized via conventional solid-state reaction route at 1200°C, yielding a monoclinic phase [P2₁/c (14)] with successful substitution of Eu³⁺ at La³⁺ sites. Developed phosphors exhibit intense red Eu³⁺ emission dominated by the hypersensitive ⁵D₀→⁷F₂ transition, indicating a non-centrosymmetric monoclinic environment, with optimal emission at 8 mol% Eu³⁺ doping beyond which dipole–dipole quenching occurs. Temperature-dependent photoluminescence (TD-PL) analysis reveals gradual thermal quenching, with ∼30% emission retained at 440 K, following Arrhenius-type trend with moderate activation energies of 0.3464 and 0.3024 eV under 292 nm excitation, and 0.2873 and 0.2667 eV under 467 nm excitation during the heating and cooling cycles, respectively. To assess their practical applicability, poly(methyl methacrylate) as thermoplastic resin-dispersed phosphor integrated onto a glass slide exhibits intense red emission with high color purity, stable CIE coordinates, and low correlated color temperature (CCT). Chromaticity coordinates (CIE) remain in the red region with high color purity across the investigated temperature range, underscoring the potential of Ba₂LaMoO₆:Eu³⁺ phosphors as promising red-emitting materials for optoelectronic and solid-state lighting applications.