Preparation And Properties Of Lanthanum Based Oxide Nanowire Arrays

In this thesis,multi-component rare earth oxides nanowire arrays（NWAs）were fabricated in the nano channel of porous alumina（AAO）template by chemical co-deposition reactions with negative pressure suction.The morphology,structure and chemical composition of the NWAs were characterized by SEM、TEM、XRD、EDS,and their fluorescence performances were investigated by fluorescence spectrometer（PerkinElmer LS-5 5）.The formation mechanisms and the optimum process conditions of fabrication NWAs were studied,and meanwhile,the doping different elements and the content of doping Eu³⁺ for the fluorescence intensity of NWAs were discussed.The main results are as follow:1.LaTb_xO_y、LaNi_xO_y、La_xO_y:Eu³⁺、LaTb_xO_y:Eu³⁺、LaNi_xO_y:Eu³⁺NWAs were successfully fabricated by AAO template,which are amorphous,uniform and large area orderly for their morphology.The influence factors,such as,the concentration of reactants,reaction time,negative pressure,and decomposition temperature were studied for controllable synthesis of NWAs.2.The fluorescence performance of doping Eu³⁺ LaTb_xO_y:Eu³⁺NWAs.was studied.The results show that there are two emission peaks at 619nm（strong emission peak）and 710nm（weak emission peak）with excitation wavelength of 394nm,which corresponds to the ⁵D₀-²F₂ and the ⁵D₀-⁷F₄ energy level transition of Eu³⁺ and it is red shift,respectively.There has not the fluorescence emission peak at 544nm corresponding to ⁵D₄-⁷F₅ energy level transition of Tb3+ in fluorescence experiment,which is masked by the emission of substrate from AAO.3.There have not any fluorescence emission peaks for LaTb_xO_y and LaNi_xO_y NWAs with excitation wavelength of 394nm,however,there are two emission peaks for La_xO_y:Eu³⁺and LaTb_xO_y:Eu³⁺ NWAs in red region due to doping Eu³⁺,respectively.The results indicated that there are fluorescence enhancement of Tb³⁺and the fluorescence quenching of Ni²⁺ in above NWAs.When the doping concentration of Eu³⁺ is 8%,Ihe fluorescence intensity reaches a maximum.LaTb_xO_y:Eu³⁺ and LaNi_xO_y:Eu³⁺ NWAs will be candidate to as medical imaging or bio labeling based on the fluorescence enhancement of Tb³⁺ and the fluorescence quenching of Ni²⁺ in the red region.