Preparation And Characterization Of Rare Earth Fluorides Micro/Nanomaterials

The thesis showed the feature, luminescence mechanism and properties of rare earth fluoride materials. NaLuF4, NaYF4, NaGdF4phosphor powders were synthesized by a facile hydrothermal approach. The main results were obtained as following:1. Growth mechanism of β-NaLuF4modified by different morphology agents had been discussed. β-NaLuF4of cross growth were synthesised when sodium citrate was as morphology agent. β-NaLuF4with tubular structure were produced with SDS modifying. When using CTAB as the morphology agent, it was found that the prepared samples were still tubular, but with holes. The properties of samples were detected by SEM and TEM. Upconversional luminescence properties of β-NaLuF4:Yb,Er/Tm/Ho were also discussed.2. The influence of codoped Gd3+was studied in β-NaLuF4:Eu3+. Fluorescent intensity was the strongest as doped50%Gd3+of the whole rare earth ions. When doping10%Gd3+, the intensity was the weakest. The emission peaks were atributed to the transition of5D2â†'7F0(467nm),5D2â†'7F2(490nm),5D2â†'7F3(512nm),5D1â†'7F1(537nm),5D1â†'7F2(557nm),3D0â†'7F1(593nm),5D0â†'7F2(618nm), respectively. The fluorescent intensity was parabola shape with the concentration of Gd3+increasing, which was first increased, then reduced. It showed near white light zone in the CIE coordinates figure when50%Gd3+and1%Eu3+codoped in β-NaLuF4.3. NaYF4, NaGdF4and NaLuF4samples prepared by hydrothermal reaction with the same condition were obtained. The fluorescent properties were discussed in Yb3+and Tm3+codoped samples. As a result, the luminous intensity of NaLuF4:Yb,Tm was stronger than that of NaGdF4:Yb,Tm.