Abstract: The ionic liquid (1-butyl 3-methyl imidazolium tetrafluoroborate) was the reaction system and the fluorine source of Lanthanum fluoride,and the effects of raw materials' stoichiometric ratio on the synthesis and morphology were also studied.The reaction mechanism was analyzed.The NaLaF4:Er/Yb and LaF3:Er materials were characterized and analyzed by XRD,SEM and other methods.Under 980 nm excitation,the up-conversion luminescence properties of the sample were measured,and the influence of Er3+ concentration and Yb3+ doping on the up-conversion luminescence properties were analyzed.The up-conversion luminescence properties of NaLaF4:Er and LaF3:Er in a temperature range of 303-583 K were measured.The temperature dependence of the fluorescence intensity ratio of 524 nm and 542 nm was discussed.

Key words: The ionic liquid (1-butyl 3-methyl imidazolium tetrafluoroborate) was the reaction system and the fluorine source of Lanthanum fluoride,and the effects of raw materials' stoichiometric ratio on the synthesis and morphology were also studied.The reaction mechanism was analyzed.The NaLaF4:Er/Yb and LaF3:Er materials were characterized and analyzed by XRD,SEM and other methods.Under 980 nm excitation,the up-conversion luminescence properties of the sample were measured,and the influence of Er3+ concentration and Yb3+ doping on the up-conversion luminescence properties were analyzed.The up-conversion luminescence properties of NaLaF4:Er and LaF3:Er in a temperature range of 303-583 K were measured.The temperature dependence of the fluorescence intensity ratio of 524 nm and 542 nm was discussed.