Preparation And Properties Of Several Rare Earth Coordination Polymers Micro/Nanomaterials And Their Membranes

In recent years,lanthanide coordination polymers（Ln-CPs）have attracted explosive attention as an emerging type of multifunctional materials.Compared with the traditional functional materials,Ln-CPs have more excellent properties including fluorescence properties,catalytic properties,adsorption properties and magnetic properties,so that they are widely used in many fields,such as homogeneous catalysis,gas separation and storage,biological imaging,nonlinear optics,chemical sensing,resonance imaging and so on.In this study,Ln-CPs with luminescent properties were synthesized by solvothermal method and mixed solvothermal method.Europium-based CPs hollow spheres,europium-based thenoyltrifluoroacetone CPs nanospheres,terbium-based CPs micro/nanospheres and gadolinium-doped Yb³⁺,Er³⁺ up-conversion micro-nanospheres and their membranes.A series of characterization were carried out,and the luminescent properties were studied.The main contents of thesis are as follows:（1）Eu（Ш）-based CPs: Ligand-dependent morphology and photoluminescence propertiesEu（III）-based CP hollow spheres have been successfully synthesized via a facile template-free solvothermal strategy with 2-aminoterephthalic acid（H2ATPA）as the organic linker.Meanwhile,the photoluminescence（PL）properties and temperature-dependent PL have also been investigated.In addition,using 1,4-benzenedicarboxylate（BDC）and its derivatives as organic ligands,and their morphology and fluorescence properties were also compared.The order of the PLQY and the emission lifetimes were fundamentally the same as the order of the fluorescence intensity.Besides,the temperature-dependent fluorescence of Eu-ATPA CP indicates that lower temperature can enhance fluorescence emission intensity of Eu-ATPA CP.（2）Lanthanide CPs micro/nano-spheres based on thenoyltrifluoroacetone: synthesis,characterization and luminescence properties.Eu（III）-based CP（EuCP）micro/nanosphere were prepared by mixed solvothermal method using Eu（NO3）3 ? 6H2 O as the metal ion source and thenoyltrifluoroacetone as an organic ligand.The luminescent properties of the precursor were studied.In addition,a series of CP spin-coating membranes were prepared by spin-coating method,and their fluorescence intensities were compared.In addition,the photostability and thermal stability of the spin-coated membranes were investigated.The results show that after doping with coordination polymer can not only increase the optical properties of the material,but also enhance the thermal stability.（3）Uniform Tb-based CP microspheres and its membranes: Synthesis,characterization and luminescent properties.Tb（NO3）3 ? 6H2 O and 2-nitroterephthalic acid were used as raw materials,and the uniform terbium-based（Tb-based）CP microspheres were successfully synthesized.The precursor was characterized,and its fluorescence properties were studied.On this basis,spin-coating method was used to prepare its spin-coating membranes,and their luminescence properties were studied.In addition,Eu³⁺ was doped into the Tb-CP microsphere precursor,and the fluorescence intensities of the samples that are doped with different proportions of Eu³⁺ were discussed.The results indicated that the mechanism of metal-to-metal charge transfer（MMCT）from the Tb³⁺ to Eu³⁺centers.（4）Gadolinium-based CP（Gd-CP）microspheres doped with rare earth(Yb³⁺,Er³⁺): synthesis,characterization,up-conversion luminescence properties and the Preparation of its spin-coating membrane.Uniform Yb³⁺and Er³⁺co-doped Gd-CP microspheres were synthesized by mixed-solvothermal method using 2-nitroterephthalic acid as the organic linker.In addition,Gd2O3: Yb³⁺,Er³⁺ was obtained by calcining the CP precursors under high temperature.The upconversion luminescence properties of the products before and after calcination were compared.The results show that Gd-CP: Er³⁺,Yb³⁺ shows bright red upconversion luminescence.characteristic up-conversion（UC）emissions of red(Er³⁺ 4F9/2→4I15/2).More importantly,Gd2O3: Yb³⁺/Er³⁺ exhibits both green(Er³⁺ 2H11/2,4S3/2→4I15/2)and red(Er³⁺ 4F9/2→4I15/2)emission.On this basis,spin-coating method was used to prepare the membrane which was comprised of organic glass microspheres and Gd-CP: Yb³⁺,Er³⁺,and their morphologies were observed.