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

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)4O9phosphor exhibits superior resistance to thermal quenching compared to Ba3(Y0.95Eu0.05)4O9and 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.