Intra-molecular Energy Transfer In Lanthanide Complexes And Properties Research Of Doped Polymer

Rare earth complex which bears unique fluorescence characteristics, such as longlifetime, good monochromaticity, large Stocks shift, has attracted grate interest ofinventors. As incorporating rare earth complex to polymer matrix, the dissociation ofcomplex will be overcome and the advantages of polymer materials such as rich inraw material ingredient, light weight, low cost, strong shock resistant ability, goodmolding and processing performance will present. Because of these advantages,polymer materials containing rare earth complex exhibit great potential applied valuein fluoroimmunoassays, display, energy conversion device, laser materials and opticalamplifier.Intramolecular energy transfer in rare earth complex is an important step whichconcerns fluorescence quantum yield, lifetime. With the increases of the rare earthtypes and the promotion of the experiment and test techniques, the investigation ofintramolecular energy transfer penetrates farther gradually. However, the energytransfer process is still an important research direction.In this work, the complexes which contain singlet state energy transfer have beenprepared and incorporated into polymer matrix. By means of Judd-Ofelt theory andspectra anaylsis, the flourescence properties with different energy transfer path havebeen investigated. The content of this dissertation are listed as below:1. The effects of energy transfer processes on flourescence have been studied in thecomplex Eu(TTA)₃Dpbt. The spectra properties, efficiencies of energy transferand lifetime of Eu ions for singlet and triplet state processes are investigated. As aresult, the spectra properties are not sensitive to energy transfer path. However theefficiency of singlet state transfer is higher than triplet state. In addition, complexexhibits long lifetime by the energy transfer from singlet state. The effects ofpolymer matrix on the flourescence of Eu complex are also studied. It can beconcluded that molecular chain in polymers has restricted the thermal motion ofthe complex, and the fluorescence quench by the thermal decay has beendecreased2. A planar luminescent solar concentrator (LSC) has been prepared by means ofEu(TTA)₃Dpbt which shows absorption in visible light region, and compared withEu(TTA)₃Phen doped LSC. Both of them do not has self-absorption, however, the LSC with Eu(TTA)₃Dpbt has wider absorption band. The external quantumefficiencies and energy conversion efficiencies have been mearsured. As a result,the LSC containing Eu(TTA)₃Phen has wilder responsive spectra band and higherenergy conversion efficiency.3. The effects of solvent polarity on different intramolecular energy transferprocesses have been studies. The result indicates that triplet state process is not sosensitive to solvent polarity as singlet state process. In singlet process, the energytransfer efficiency decreases with the increase of the solvent polarity. In addition,a test method of Ag ion concentration measurement has been developed. Theinteraction of Ag ion and second ligand for rare earth complex will weaken theflourescence intensity. Through the experiment, this test method can provide theAg ion concentration by detecting the intensity of the emission peak. Low dosageof rare earth complex and high sensitivity are two merits of this test method. Thedetection limit can be minimized to 10-6mol/L magnitude.4. The complex Nd(TTA)₃Dpbt with singlet state transfer process has beensynthetized and doped in PMMA, comparing with four Nd complex which havediffernet second ligands. Judd-Ofelt parameters of these complexes have beencalculated using the oscillator strength of each transition. Combinating absorptionand flourescence spectra, energy levels, transition probabilities and fluorescencebranching ratios have been investigated. The transition⁴F_3/2→⁴I_11/2which emit at1066nm has the largest fluorescence branching ratio of 88.3%. This value isbeneficial to generate laser and extremely rare in the Nd doped materials that havebeen reported in the literature. Analyzing the fluorescence branching ratios ofcomplex with different second ligands, it is concluded that Judd-Ofelt parametersΩ2influence fluorescence branching ratio of transition⁴F_3/2→⁴I_11/2. The laserparameters of five Nd doped PMMA are also calculated and compared withinorganic optical materials. As a result, PMMA doped with Nd(TTA)₃Phen andNd(TTA)₃Dpbt have large gain cross section which make them have the potentialapplications in lasers and optical amplifiers...