Fluorescent Properties Of Rare-earch Complexes And Its Composites

Organic rare-earth complexes can emit strong fluorescence due to the special 4f electron structure of rare-earth and outstanding absorbing light ability of organic ligands. Rare-earth/polymer composites have not only the high fluorescent properties but the good processing ability, chemical stability and mechanical strength. Hence, the fluorescent composites can be applied in the fields of display, probes and laser materials. In this thesis, in-situ reaction and electrospinning method were used to prepare the rare-earth/polymer composites with the fine dispersion and good interfacial. The main work are list as follow:1. The unsaturated organic molecules including acrylic acid and oleic acid were introduced into rare-earth complexes. The contribution of every organic ligands on the fluorescent properties of rare-earth complex was discussed detailedly by introducing the ligands one by one.2. Sm(TTA)2(Phen)(AA) complexes were mixed with the HNBR and peroxide to form uncured composites. The composites were vulcanized at high temperature to obtain cured Sm(TTA)2(Phen)(AA)/HNBR composites. Eu(OAH)3TTA/SiR and Eu(OAH)3TTA/NBR fluorescent composites were also prepared with the similar process. The mechanism of in-situ reaction happened in the curing process was investigated deeply. The effect of in-situ reaction on the dispersion and crystal state of rare-earth complex in the matrix was also discussed. TEM and XRD tests showed the rare-earth complexes were dispersed finely in the polymer matrix after the in-situ reaction. The crystallinity of rare-earth complexes was absent dramatically after the curing process. The dispersion phase of the cured composites was composed of completely almost nanometersized poly(rare-earth complexes). This kind of fine dispersion structure enhanced the asymmetry of the chemical environment around rare-earth ions. The fluorescent intensity and quantum yields of the cured composite were much higher than that of the uncured one with the same rare-earth complexes content due to the in-situ reaction.3. Tb(acac)3Phen/PVP nanofibers with diameters of 60～200 nm were prepared by electrospinning. The effect of solvent evaporation rate, PVP concentration, driving voltage on the morphology of the PVP fibers was investigated detailedly. TEM, XRD and EDS tests revealed the Tb(acac)3Phen complex predominantly existed as molecular clusters and/or nanoparticles with sizes smaller than 10 nm. This distribution of Tb(acac)3Phen complex in the fiber is similar with the uniform distribution of the complex units along macromolecular chains in the luminescent copolymers containing Eu complexes. Fluorescence tests showed the fine dispersion of the Tb(acac)3Phen decreased the nonradiative transition rate, and resulting increased fluorescent intensity and lifetimes of the fibers.4. EPDM nanofibers with diameters of 100-200 nm were prepared by coaxial electrospinning for the first time. The core-sheath structure was obtained mainly by restricting elastic recoil of EPDM with outer plastic PVP and ultraviolet curing method. The effect of injecting rarte of outer and inner solution, driving voltage, ultraviolet and peroxide curing process on the core-sheath structure was investigated detaildly.Fluorescent elstomers-based nanofibers were obtained by adding Eu(TTA)3Phen and Tb(acac)3 complexes into the EPDM electrospun solution. The rare-earth complexes were also predominantly dispersed as molecular clusters and/or nanoparticles with sizes smaller than 10 nm. Luminescence studies revealed that the luminescent efficiency of fibers are higher than that of the neat complexes when the concentration of complexes was up to 15wt%...