Synthesis and photoluminescence of double perovskite La₂LiSbO₆:Ln³⁺ (Ln= Eu, Tb, Tm, Sm, Ho) phosphors and enhanced luminescence of La₂LiSbO₆:Eu³⁺ red phosphor via Bi³⁺ doping for white light emitting diodes

La₂LiSbO₆: Ln³⁺ (Ln = Eu, Ho, Dy, Sm, Tm) and La₂LiSbO₆: Eu³⁺, Bi³⁺ phosphors were synthesized by conventional solid state reaction method. They were characterized by X-ray diffraction patterns, SEM, photoluminescence spectra, diffuse reflectance spectra and temperature-dependent luminescence spectra. Among these doping Ln³⁺ ions, Eu³⁺ was found to be most suitable for La₂LiSbO₆ host because of the relatively high energy transfer efficiency from host La₂LiSbO₆ and the high quenching concentration. By co-doping Bi³⁺ ions, the fluorescent intensity of La₂LiSbO₆:Eu³⁺ could be further significantly increased. The energy transfer efficiency and the energy transfer mechanism in La₂LiSbO₆: Ln³⁺and La₂LiSbO₆:Eu³⁺, Bi³⁺ were procured. The good thermal stability of the composition optimized La_1.63Bi_0.01Eu_0.36LiSbO₆ phosphor was also illustrated by the temperature-dependent luminescence spectra. These merits demonstrated this material could be a potential candidate as the red light component in the field of phosphor – converted LEDs.