Enhanced Luminescence and Thermal Stability in High Gd3+/Eu3+ Co-Doped Ba3Y4O9 Phosphors via Co-Precipitation Method

Abstract

The co-precipitation method was successfully used to synthesize Ba3(Y0.6−xGd0.4Eux)4O9 (0.01 ≤ x ≤ 0.09) phosphors with heavy Gd3+ doping, resulting in significantly enhanced thermal stability and luminescence performance. Structural analyses confirm that Gd3+ and Eu3+ ions substitute Y3+ in the lattice, causing lattice expansion and improving crystal asymmetry, which enhances Eu3+ emission. The incorporation of Gd3+ creates efficient energy transfer pathways to Eu3+ while suppressing non-radiative relaxation, leading to stable fluorescence lifetimes even at elevated temperatures. With a thermal activation energy of ~0.3051 eV, the Ba3(Y0.55Gd0.4Eu0.05)4O9 phosphor exhibits superior resistance to thermal quenching compared to Ba3(Y0.95Eu0.05)4O9 and many conventional red phosphors. Furthermore, the reduced color temperature and stable emission spectra across a wide temperature range highlight its potential for advanced lighting and display technologies in high-temperature environments.