Preparation And Characterization Of Rare Earth Ions-doped Fluorides Low-dimensional Nanomaterials

Rare earth quadrifluoride is one of the high efficient matrixes for rare earth ion-doped luminescent materials owing to its bumper4f levels and low vibrational energies. It has been extensively applied in the fields of solar cell, anti-fake, medical testing, biological tag, etc. Nowadays, rare earth quadrifluoride with various morphologies including sphere-like structure, flake-shaped structure, rod amd hollow tubes have been prepared. There have been no reports on the rare earth quadrifluoride nanofibers and nanobelts. In order to study their properties, a preparation technique of rare earth quadrifluoride nanofibers and nanobelts is urgently needed. Electrospinning is the best choice to fabricate one-dimentional nanomaterials due to its simple and highly reproducible process. Therefore, fabrication of rare earth ions-doped rare earth quadrifluoride nanofibers and nanobelts via electrospinning will be a meaningful subject of significance.For the first time. PVP was used as template to fabricate NaYF4, LiYF4nanofibers and nanobelts by electrospinning combined with fluorization technique in this dissertation. Then MYF4:RE3+(M=Na, Li; RE=Eu,Tb) down-conversion luminescence nanomaterials and MYF4:Yb3+/Er3+(M=Na, Li) up-conversion luminescence nanomaterials were obtained on the basis of fabrication of NaYF4and LiYF4nanomaterials. Luminescence properties of these nanomaterials were also studied.The samples were characterized by XRD, SEM and PL. Results show that hexagonal NaYF4:RE3+(RE=Eu, Tb, Yb/Er) nanomaterials and tetragonal LiYF4:RE3+(RE=Eu, Tb. Yb/Er) nanomaterials were prepared by calcination of PVP/[rare earth nitrate] composite nanomaterials at600℃for4h followed by fluorization of the relevant mixed oxides nanomaterials at280℃for2h using NH4HF2as fluorinating agent and deammonia at500℃for3h. Diameters of these fibers are80-200nm. Width and thickness of these nanobelts are5-15μm and60-180nm. respectively. The strongest emission peak of MYF4:Eu3+(M=Na, Li) nanomaterials was attributed to5D0â†'7F2transition of Eu3+. The strongest emission peak of MYF4:Tb3+(M=Na. Li) nanomaterials was ascribed to5D4â†'7F5transition of Tb3+; and the strongest emission peak of MYF4:Yb3+/Er3+(M=Na. Li) nanomaterials was attributed to4S3/2â†'4I15/2transition of Er3+...