Synthesis and Photoluminescence Properties of LaAlO₃: Tb³⁺ Nanophosphors Prepared by Combustion Method

LaAlO₃:Tb³⁺ nanophosphors were synthesized via a combustion method followed by calcination at 1000°C. Their structural and optical properties were characterized using XRD, FTIR, SEM, and photoluminescence analyses. XRD results confirmed the formation of a single-phase rhombohedral perovskite structure without secondary phases, indicating successful incorporation of Tb³⁺ ions into the host lattice. FTIR analysis supported the structural stability and absence of hydroxyl-related impurities, while SEM images revealed a porous morphology typical of combustion-derived nanomaterials. The photoluminescence spectra exhibited characteristic Tb³⁺ emissions, with a dominant green emission at ~545 nm (⁵D₄ → ⁷F₅). The luminescence intensity strongly depends on Tb³⁺ concentration in the 1-7 wt% range, increasing up to 5 wt% and decreasing at higher concentrations due to concentration quenching. This behavior is attributed to nonradiative energy transfer via multipolar interactions at higher dopant levels. The enhanced luminescence is associated with improved crystallinity after high-temperature calcination. These results demonstrate that LaAlO₃ is a stable host for Tb³⁺ ions and highlight the importance of optimizing dopant concentration to achieve efficient green emission for potential photonic applications.