Temperature-dependent luminescence and defect centre analysis of thermally stable cerium-doped aluminosilicate phosphors

Abstract

This study aims to conduct a comprehensive characterisation of Sr₂Al₂SiO₇: Ce phosphors, addressing critical gaps in existing research, particularly the limited exploration of the correlation between thermoluminescence and electron spin resonance phenomena, as well as the absence of reports on the temperature-dependent luminescence characteristics of thermally stable cerium-doped aluminosilicate phosphors. Advanced spectroscopic and analytical techniques were employed to elucidate the complex electronic states and defect centres within the crystal lattice of these phosphors. Density functional theory simulations were utilised to explain the energy gap discovered through diffuse reflectance spectroscopy studies, with the density of states analysis attributing the presence of electronic density states near the valence band to the addition of Ce³⁺ dopant. Temperature-dependent luminescence studies revealed exceptional thermal stability, with only a 15% loss in luminescence intensity at 210 °C, highlighting the material’s potential for high-performance LED applications. This research emphasises the novel correlation between thermoluminescence and electron spin resonance, providing valuable insights into defect-assisted recombination processes and the thermoluminescence emission mechanism. The study’s findings bridge theoretical and experimental frameworks, establishing Sr₂Al₂SiO₇: Ce as an innovative material with promising applications in γ-dosimetry, optoelectronic devices, and next-generation LED technologies. This work underscores the significance of exploring previously unexamined aspects of cerium-doped aluminosilicate phosphors, contributing to advancements in luminescent materials.