Synthesis and luminescence properties of double perovskite Gd2MgTiO6:Eu3+ red phosphors for white light-emitting diodes

A series of double perovskite Gd2(1-x)MgTiO6:xEu(3+) (x = 0.01, 0.05, 0.1, 0.15, 0.2, 0.3 and 0.5) phosphors were successfully synthesized. Two rare earth ions occupy the A-site in this host, which benefits the doping of Eu3+ ions. The crystal structure, microstructure were examined by X-ray diffraction and scanning electron microscopy. Luminescence properties, such as excitation and emission spectra, CIE coordinates and concentration quenching were systematically investigated. A weak magnetic dipole transition (D-5(0)-F-7(1), 590 nm) and a strong electric dipole transition (D-5(0)-F-7(2), 616 nm) existed in the emission spectra. The quenching concentration for hypersensitive electric dipole transition of Eu3+ reached up to 15.0 mol%. The delayed concentration quenching was observed in Gd2MgTiO6:Eu3+ phosphors. The theoretical quenching concentration was obtained based on Ozawa's theory, and the quenching mechanism on Dexter's theory. All the results indicate that Gd2MgTiO6:Eu3+ has great potential in solid state lighting.