Structural and luminescent properties of Eu³⁺-doped double perovskite BaLaMgNbO₆ phosphor

Eu³⁺-activated BaLaMgNbO₆ red-emitting phosphors were synthesized by a high-temperature solid-state reaction method. Phase analysis and luminescence were characterized by X-ray diffraction (XRD) and photoluminescence excitation and emission spectra. The XRD patterns showed that BaLaMgNbO₆ had a monoclinic structure with space group P21/n. The excitation spectra consisted of a broad charge-transfer band and some sharp f-f absorption peaks characteristic of Eu³⁺. The intensity ratio of I₆₁₅/I₅₉₀ was used to detect the chemical environment of Eu³⁺. The chromaticity coordinates of BaLa_0.7Eu_0.3MgNbO₆ were (0.67, 0.33), indicating that the BaLaMgNbO₆:Eu³⁺ phosphors were excellent red-emitting phosphors. Under excitation by near-ultraviolet (UV) and blue light, the phosphor not only exhibited intense red emission but also showed high color quality. The Ozawa and Dexter energy-transfer theories were employed to calculate the theoretical quenching concentration and determine the concentration quenching mechanism. In addition, the activation energy of BaLa_0.7Eu_0.3MgNbO₆ was calculated through the Arrhenius equation. A configurational coordinate diagram was used to explain the thermal quenching mechanism.