Study On Morphology And Luminescence Properties Of Rare Earth Doped Metal Oxide Composites

This thesis prepared the different morphologies ZnO,TiO₂/ZnO and ZnO/SnO₂ composites,which were used as matrixes to doping Eu³⁺,the influences of the different synthesis conditions to morphologies of the prepared materials were discussed,and the optimal synthesis conditions and Eu³⁺ doping ratio were confirmed.Eu³⁺ were doped during the synthesis process of the MOF-5(Zn-MOF)and MOF-5:xEu luminescence materials were prepared.The influences of Eu³⁺ doped ratio to morphology and luminescence property of materials were discussed.The main research contents are as follows:Carnation,succulent and prayer wheel like ZnO materials were prepared by template method,which were used as matrixes to dope Eu³⁺ by hydrothermal method.When carnation and succulent like ZnO were used as matrixes,the morphologies of matrix samples were basically maintained in the prepared ZnO:xEu composites.However,when prayer wheel like ZnO was used as matrix,the morphology of matrix sample was transformed into crystal-flower like morphology with the accumulation of rod-like particles in the prepared ZnO:xEu composite.The luminescence properties of the prepared ZnO:xEu composite were inspected.The prepared materials showed the excellent yellow emission,and the crystal-flower like ZnO:xEu composite showed the best luminescence property.TiO₂/ZnO:xEu luminescence composites were prepared by sol-gel method.The band gap of the TiO₂/ZnO composite was narrowed through the recombination action between the wide band gap semiconductors TiO₂ and ZnO,the absorption capacity to excitation light was enhanced,its absorption spectrum was fully overlapped with the excitation spectrum of Eu³⁺ ions,which realized the efficient energy transfer between matrix and Eu³⁺luminescence center.The prepared materials showed the gel block structure with the accumulation of gel particles whose crystal structures were mainly the amorphous phase based on TiO₂.When the doping amount of Eu³⁺ was 0.04,the prepared TiO₂/ZnO:xEu composite showed the strongest luminescence properties.The sample showed much higher orange emission under the excitation light of 396 nm.Eu³⁺ doped MOF-5 luminescence materials were prepared by coprecipitation method at room tempreture.The prepared materials possessed the cuboid morphology.Eu³⁺ ions not only were distributed in the pores of MOF-5,but also partly replaced Zn2+ ions into the framework of MOF-5.The luminescence property of the prepared materials was inspected,and the prepared materials showed much higher red emission under the excitation light of288 nm.Using CTAB as template reagent,pine needle like porous ZnO/SnO₂ composite was synthesized,which was acted as matrix to prepare the ZnO/SnO₂:xEu luminescence materials by hydrothermal method.The influence of Eu³⁺ doping ratio to the morphology of the prepared ZnO/SnO₂:xEu composite was inspected,and the prepared materials showed the perfect pine needle like morphology when the doping amount of Eu³⁺ was 0.05.The luminescence property of the prepared composite was inspected,and the materials showed much higher red emission under the excitation light of 400 nm.