Optical performance and luminescence properties of Dy3+-doped LaMgB5O10 phosphors

Abstract

Despite significant advancements in borate-based phosphors, improving luminescent efficiency and thermal stability, particularly at high temperatures, remains a persistent challenge. In this study, Dy³⁺-doped LaMgB₅O₁₀ (LMBO) phosphors were synthesized and characterized for their photoluminescent properties to address these issues. Under 344 nm excitation, the Dy³⁺-activated LMBO phosphors exhibited strong luminescence with characteristic peaks at 482 nm (blue), 578 nm (yellow), and 663 nm (red), corresponding to specific Dy³⁺ transitions. Optimal luminescence was achieved at a doping level of 2 wt% Dy³⁺, beyond which quenching effects reduced emission intensity. The critical quenching distance ($R_c$) was estimated at 24.66 Å, indicating predominant non-radiative energy transfer. Moreover, thermal quenching was reduced, with the activation energy for thermal quenching determined to be 0.1975 eV, demonstrating that the material can maintain reasonable luminescence efficiency at elevated temperatures. Time-resolved photoluminescence spectroscopy revealed multi-exponential decay behavior, indicating the presence of multiple decay processes. The average luminescence lifetimes were calculated as 632 µs for the 2 wt% Dy³⁺ sample and 539 µs for the 3 wt% Dy³⁺ sample, with a clear concentration quenching effect observed at higher dopant levels. Colorimetric analysis in the CIE 1931 color space revealed a shift toward yellow with increasing Dy³⁺ concentration, achieving a correlated color temperature (CCT) of 6595 K at 2 wt% Dy³⁺. This shift supports the material’s potential for photonic and lighting applications. These findings highlight a significant advancement in addressing the thermal stability issue in phosphor materials, making Dy³⁺-doped LMBO phosphors promising candidates for advanced photonic technologies.