Designed Synthesis, Structures And Properties Of Luminescent Lanthanide-based Molecular Materials

Luminescent molecular-based materials may be used in the applications ofemitting electroluminescent devices (OLEDs), light-emitting electrochemical cells(LECs), etc. As compared to the general organic-emitting materials,lanthanide-based luminescent materials exhibit high luminous intensity, good colorpurity, long life, high quantum efficiency, and Eu3+/Tb3+ions produced red/greenemission especially, so that they have received more and more attention not only inthe fundamental research but also in some application developments around thelanthanide luminescence. Meanwhile, the luminescence of lanthanide complexes canbe efficiently modified through some designed modulation on the organic ligandstructure. This dissertation focuses on the designed synthesis and X-ray diffractionstructural analysis of lanthanide complexes with nitrogen-containing heterocyclicligands as the second ligand. The materials have been characterized and evaluated byusing X-ray powder diffraction (PXRD), fourier transfer infrared spectroscopy(FTIR), thermal gravimetric analysis (TGA), electronic absorption spectroscopy(UV-Vis), and fluorescence spectra (PL) measurement, even studied in depth toexplore the relationships between structure and properties of the materials. The maincontents include the following three aspects:1. The study of lanthanide luminescent complexes with2-PBO as the second ligand.Four luminescent lanthanide complexes, Eu(BTA)3(PBO)[4], Eu(BTA)3(PBO)[5],Eu(BA)3(PBO)[6], Eu(TAA)3(PBO)[7], have been synthesized by utilizing samemethod of solution reaction, and all been characterized as isolated molecules byX-ray single crystal diffractions. All of Eu3+ions in the coordination polyhedralcenter adopt the eight coordination geometry.4and5are allomorphic structuresobtained from different crystallization conditions. The thermal stability of5is higherthan4with decomposition temperature at260℃vs210℃. The decompositiontemperature of compounds6and7is154℃and196℃respectively.Thefluorescence test results show5has stronger luminescent intensity than4. 2. DAF and QBO as the second ligand for the study of lanthanide luminescent.obtained six single–crystal lanthanide complexes by the solution method,Eu(BTA)3(DAF)[9], Eu(BTA)3(DAF)[10], Eu(TTA)3(DAF)[11], Eu(TAA)3(DAF)[12], Eu(TTA)3(QBO)[14], Eu(BTA)3(QBO)[15]. The structures of all complexeshave been determined by single-crystal X-ray diffraction. Their thermostability andluminescence were studied. The results showed that the difference in solubility of thecompound11, in addition to DMF, it is difficult to dissolve in other organic solvents,but it′s melting point at236℃, decomposition temperature at250℃. And theluminous of compound11is strongest.14and11have different second ligand andtheir thermal stability and luminescence properties were also quite different, thesecond ligand play a important role in the "antenna effect".3. Preparation and properties of the compound4-doped materials and films. dopedEu3+ions to Tb(BTA)3(PBO), the results of luminescence studies showed that thetriplet level energy of ligand transfer efficiently to Eu3+and Tb3+ions, but the energytransfer to Eu3+ions is more efficiently, reducing the Tb3+ions in non-radiativetransitions, the pure Eu3+compound emitting is stronger than doping compounds.4coated with PMMA, the light emitting characteristics of rare earth ions at differentexcitation wavelengths.