Fabrication And Characterization Of The Rare Earth Compound For Quasi One Dimensional Nanomaterials

Quasi one dimensional rare earth compound nanostructures such as nanowires, nanorods, nanobelts, nanotubes have attracted intensive attention owing to their unique photoluminescence and maganetic properties, which is related to the 4f shell of rare earth ions and nanostructure effects, for example, surface effect, quantum of size confinement effects. Therefore, it is interesting to seek a facile and high yield synthetic method to fabricate quasi one dimensional nanostructures for further application. In this thesis, PAA template with uniform and large-scale nanopores has been fabricated by two-step anodization, and non-stoichiometric NdxNi1-xOy nanotube arrays have been synthesized in PAA template and the performances of the NdxNi1-xOy nanotube arrays have been investigated. Moreover, a solvothermal method has been developed to synthesis Sm2O3 nanowires.The detailed researches of the thesis are as follows:(1) Porous alumina films with different pore diameters have been fabricated by two-step anodization in different electrolyte (30nm in sulfuric acid,70nm and 120nm in oxalic acid,250nm in phosphoric acid). The morphology and structure of PAA are observed by SEM and XRD, the room temperature photoluminescence properties are characterized by HITACHI (F-4500) Fluorescence Spectrophotometer. The reasons for variation of photoluminescence between PAA films prepared in different electrolyte are investigated.(2) NdxNi1-xOy nanotube arrays have been synthesized in PAA template by filtering at subatmospheric. The images of non-stoichiometric NdxNi1-xOy nanotube arrays and single nanotube are observed by SEM and TEM, respectively. SAED, XRD and EDS are employed to study the morphology and chemical composition of the nanotubes. The hysteresis loops characterized by a vibrating sample magnetometer (VSM) show that the easily magnetized direction of non-stoichiometric NdxNi1-xOy is parallel to the nanotube arrays and there exhibits magnetic anisotropy as a result of the shape anisotropy. The up-conversion of non-stoichiometric NdxNi1-xOy nanotube is investigated using HITACHI (F-4500) high-pressure xenon lamp, the results indicate that the blue up-conversion emission and green up-conversion emission are respectively occurred at 480nm and 534nm, excited by 808nm.(3) We demonstrate the produtcion of Sm2O3 nanowires through a solvothermal method followed by a dehydration process using Sm(NO3)3 as raw materials. Then SEM, HRTEM, XRD, EDS are used to investigate morphology, crystal structure and composition of the products. Room temperature photoluminescence and magnetic properties are also researched by fluorescence spectrophotometer and vibrating sample magnetometer (VSM), respectively. Effects of reaction temperature, solvothermal time and composition of solvent on the formation of nanowires have been discussed.