Abstract
The co-precipitation method was successfully used to synthesize Ba(3)(Y(0.6-x)Gd(0.4)Eu(x))(4)O(9) (0.01 ≤ x ≤ 0.09) phosphors with heavy Gd(3+) doping, resulting in significantly enhanced thermal stability and luminescence performance. Structural analyses confirm that Gd(3+) and Eu(3+) ions substitute Y(3+) in the lattice, causing lattice expansion and improving crystal asymmetry, which enhances Eu(3+) emission. The incorporation of Gd(3+) creates efficient energy transfer pathways to Eu(3+) while suppressing non-radiative relaxation, leading to stable fluorescence lifetimes even at elevated temperatures. With a thermal activation energy of ~0.3051 eV, the Ba(3)(Y(0.55)Gd(0.4)Eu(0.05))(4)O(9) phosphor exhibits superior resistance to thermal quenching compared to Ba(3)(Y(0.95)Eu(0.05))(4)O(9) 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.