Judd–Ofelt analysis and the spectroscopic elucidation of β-BaB ₂ O ₄ :Eu ³⁺ phosphors for optoelectronic applications

We have used the solid-state reaction method to prepare Eu³⁺ (1, 1.5, 2, 2.5, and 3 mol%) doped β-BaB₂O₄ phosphors. Phase purity of the prepared phosphors was confirmed using X-ray diffraction (XRD) studies. Photoluminescence (PL) measurements using 395 nm excitation exhibited three intense peaks at 593 nm, 615 nm, 653 nm, and 702 nm, respectively, due to the ⁵D₀ → ⁷F _<i>j</i> (<i>j</i> = 0, 1, and 2) transitions. The PL emission intensity will increase up to 2 mol%, and thereafter, there will be a decline due to concentration quenching. Chromaticity analysis, along with correlated colour temperature (1796 K to 1976 K), confirmed the material's potential as a warm light emitter. Diffuse reflectance spectroscopy revealed a direct bandgap energy of 4.30 eV for the optimized sample. Finally, using Judd-Ofelt intensity parameters, the calculation of critical radiative parameters, including transition probability, lifetime, and branching ratio, was carried out. The results demonstrate the efficient luminescence and excellent colour stability of β-BaB₂O₄:Eu³⁺, highlighting its potential for optoelectronic applications.