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: Ln(3+) (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 Ln(3+) 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: Ln(3+) and La2LiSbO6:Eu3+, Bi3+ were procured. The good thermal stability of the composition optimized La1.63Bi0.01Eu0.36LiSbO6 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. (C) 2019 Elsevier B.V. All rights reserved.