Construction And Characterization Of Optical Functional Rare Earth Nanostructured Materials

Optical functional nanomaterials have become one of the hotspots in the field of functional materials. Rare earth luminescent nanomaterials possess excellent optical properties, such as long fluorescence life time, narrow emission linewidth, tunable fluorescence emission wavelength, etc., which render them potential applications in fluorescent biomarkers, fluorescent display, illumination materials, fluorescence detection and etc. Because one-dimensional(1D) rare earth luminescent nanomaterials have less surface defect and are harder to agglomerate than zero-dimensional nanoparticles, they have received the researchers’ extensive concern. Photocatalytic materials are functional materials that based on light-chemical conversion to degrade organic pollutants. Owing to the high specific surface area and high surface activity, nano-sized photocatalytic materials show much better performance than bulk materials. Multifunctional nanomaterials have attracted considerable attention and extensive study of researchers due to their high integration of various functions. The multifunctional nanomaterials possessed magnetism-fluorescence or fluorescence-photocatalysis properties can be able to meet the application requirements that single functional materials may be not competent, leading to the fact that they will continue to be the focus of the future research on photoelectron devices. In this dissertation, we adopt electrospinning and electrospray technique to fabricate rare earth doped BaY2F8 and oxyhalide 1D nanomaterials which have photoluminescence property and nanostructured CeO2 photocatalyst with different morphologies, as well as two kinds of bifunctional 1D nanomaterials with magnetism-fluorescence and fluorescence-photocatalysis properties, respectively.1. Monoclinic BaY2F8:RE3+(RE=Eu, Tb) nanofibers have been successfully fabricated via electrospinning combined with double-crucible fluorination method. The products have uniform size distribution, and their diameters are 100-130 nm. They show strong fluorescence intensity.2. LaOCl:Er3+ nanofibers and nanobelts with up-conversion luminescent performance have been prepared though electrospinning followed by double-crucible chlorination method. The products are assigned to tetragonal structure, with space group of P4/nmm. The diameter of LaOCl:Er3+ nanofibers is 161.15±18.11 nm, and the width and thickness of LaOCl:Er3+ nanobelts are 6.11±0.19 μm and 116 nm, respectively. The fluorescence intensity and color of the products can be tunable by changing the doping contents of Er3+.3. Tetragonal LaOBr:Eu3+ down-conversion nanofibers with their diameters of ca. 150 nm have been constructed by using the combination methods of electrospinning and double-crucible bromination. Under the excitation of 302-nm ultraviolet light, the samples emit red fluorescence, and the strongest emission peak locates at 620 nm.4. CeO2 microspheres with tunable morphologies including solid particle, jar and porous particle have been prepared via electrospray ionization technique. CeO2 nanobelts have been synthesized via electrospinning technique. It is found that the photodegradation activity of photocatalyst is not only relevant to the specific surface area but also to the morphology.5. TiO2/SiO2/Y2O3:Yb3+, Er3+ triaxial aligned nanofibers bundles with up-conversion luminescence and photocatalysis bifunctional have been synthesized by electrospinning method using a specially designed triaxial parallel spinneret. The product is composed of a TiO2 nanofiber, a SiO2 nanofiber and a Y2O3:Yb3+, Er3+ nanofiber assembled side-by-side, and it simultaneously possesses good up-conversion luminescent and photocatalytic properties.6. Magnetic-luminescent bifunctional Fe3O4/Eu(BA)3phen/PVP hollow nano?bers have been fabricated by one-pot coaxial electrospinning technique. In electrospinning process, spinning solution is only needed to add into the outer syringe, whereas no any core spinning solution is used to directly fabricate hollow nano?bers via controlling the composition of solvent of spinning solution. An obvious hollow structure can be observed in the magnetic-luminescent bifunctional hollow nano?bers, and the products show both magnetism and luminescence.