Preparation And Characterization Of Rare Earth Fluorides Nanofibers By Electrospinning

In recent years, investigation on nanofibers has aroused much attention of the scientists all over the world due to their unique characteristics such as very large surface area to volume ratio, flexibility in surface functionalities, and superior mechanical performance compared with the relevant bulk materials. Rare earth fluorides are very important matrix for luminescence and one of the important studied materials in the solid-electrolyte field as well. They are also used as lubricants, additives of the steel and nonferrous metallic alloys. Rare earth fluorides have widely applications in the fields of electrode materials, chemical and biological sensors, etc. It will be an important subject that rare earth fluorides can be made into nanofibers and investigation of their properties and applications.In the dissertation, PVP/inorganic salts composite nanofibers were fabricated by sol-gel process and electrospinning technique, using polyvinyl pyrrolidone (PVP) and lanthanum fluoride as starting materials, LaF₃/LaOF composite nanofibers were obtained by calcination of the relative PVP/inorganic salts composite nanofibers. RE³⁺(RE³⁺=Eu³⁺,Tb³⁺)-doped luminescent nanofibers, Er³⁺-doped and Er³⁺/Yb³⁺-doped upconversion luminescent nanofibers using LaF₃/LaOF composite nanofibers as matrix were also acquired.The obtained nanofibers were characterized by SEM, XRD, TG-DTA and Fluorescence spectrophotometer. The results showed that the LaF₃/LaOF composite nanofibers and RE³⁺(RE=Eu³⁺,Tb³⁺,Er³⁺,Yb³⁺)-doped LaF₃/LaOF composite nanofibers were uniform one-dimensional structure. The homogeneous diameters of the nanofibers were in the range of 130-170nm, and the mean diameter was 150nm. At room temperature, the fluorescence spectra of LaF₃/LaOF composite nanofibers doped with RE³⁺(RE³⁺=Eu³⁺,Tb³⁺) were measured. It was found that the peaks position of the spectra of the nanofibers were similar to those of the relative fluorescent nanoparticles. At room temperature, these two kinds of upconversion luminescent nanofibers, namely, LaF₃/LaOF composite nanofibers doped with Er³⁺ and Er³⁺/Yb³⁺ were pumped by 980nm laser and the upconversion luminescence was achieved. The upconversion emission spectra of the upconversion luminescent nanofibers were the same as those of the relative upconversion luminescent nanoparticles. Some meaningful new results were obtained and laid a foundation of the further study of properties of fluorides nanofibers.