Low temperature-synthesized MgAl2 O4 :Eu3+ nanophosphors and their structural validations using density functional theory: photoluminescence, photocatalytic, and electrochemical properties for multifunctional applications

Abstract

A low temperature-assisted and oxalyl dihydrazide fuel-induced combustion synthesized series of uncalcined MgAl₂ O₄ :Eu³⁺ nanophosphors showed an average crystallite size of ~20 nm, and bandgap energy (E_g ) of 4.50-5.15 eV, and were validated using density functional theory and found to match closely with the experimental values. The photoluminescence characteristic emission peaks of Eu³⁺ ions were recorded between 480 and 680 nm. The nanophosphors excited at 392 nm showed f-f transitions assigned as ⁵ D₀ →⁷ F_J (J = 0, 1, 2, and 3). The optimized MgAl₂ O₄ phosphors had Commission Internationale de l'Eclairage coordinates in the red region, a correlated colour temperature of 2060 K, and a colour purity of 98.83%. The estimated luminescence quantum efficiency ( $\eta$ ) was observed to be ~63% using Judd-Ofelt analysis. Electrochemical and photocatalytic performance were explored and indicated its multifunctional applications. Therefore, MgAl₂ O₄ :Eu³⁺ nanophosphors could be used for the fabrication of light-emitting diodes, industrial dye degradation, and as electrodes for supercapacitor applications.

Keywords: Judd-Ofelt parameter; MgAl2O4:Eu3+; electrochemical performance; nanophosphors; photocatalysis; photoluminescence; solution combustion synthesis.