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 BaLa0.7Eu0.3MgNbO6 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 BaLa0.7Eu0.3MgNbO6 was calculated through the Arrhenius equation. A configurational coordinate diagram was used to explain the thermal quenching mechanism.