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On Dedign, Synthesis, And Luminescence Performances Of Low-cost Metal Complexes

Posted on:2011-10-12Degree:DoctorType:Dissertation
Country:ChinaCandidate:L M ZhangFull Text:PDF
GTID:1101360305490372Subject:Condensed matter physics
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By using various ligands and their corresponding complexes, detailed analyses have been devoted to the following issues. (1) How to modulate the complexes absorption edges by controlling energy levels of ligands molecular orbitals, increase or decrease them, so that the emissions of complexes can be controlled; (2) How dose the inner- and inter-molecular actions effect photophysical properties of their corresponding complexes; (3)How to decrease the excited state lifetimes of RE-based emitters; (4) How dose the water-soluble RE-based eitters respond to Fe ion. The above mentioned research efforts lead to the following results:(1) Ligands with highπ* as well as their corresponding [Cu(N-N)(POP)]BF4 and halogen-bridged Cu(I) complexes were synthesized. Experimental data suggest that both diimine ligands and phosphorous ligands that possesses highπ* can increase the energy gap between HOMO and LUMO. The corresponding absorption edges were blue shifted into UV region successfully. Consequently, the emissions were also blue shifted, resulting in phosphorescent emissions centering at ~440 nm and ~470 nm.(2) We report a series of [Cu(N-N)(P-P)]BF4 complexes based on two phosphorous ligands and three 1,10-phenanthrolin derived diimine ligands, including their syntheses, characterizations, crystal structures. Their photophysical properties were experimentally measured and theoretically analyzed by time-dependent density functional theory (TD-DFT). It's found that the introduction of too many fused phenyl rings into diimine ligand leads to luminescence absence of corresponding [Cu(N-N)(P-P)]+ complexes at room temperature. A detailed analysis suggests that the thermal activated electron-configuration transformation between the [Cu(N-N)(P-P)]+ triplet metal-to-ligand-charge-transfer (3MLCT) state and the lowest lying excited state of its diimine ligand (3LC) is responsible for the luminescence quenching.(3) The previously well studied and reported [Cu(phen)(POP)]BF4 exhibits new features: the phosphorescence is largely enhanced after being processed by n-hexane or petroleum ether, including large scale emission blue shift, dramatically improved emission yield and longer excited state lifetime. Systematical studies reveals that the phosphorescence enhancement phenomenon is caused by theπ-stacking of [Cu(phen)(POP)]BF4 molecules and this phenomenon exists widely in [Cu(N–N)(P–P)]BF4 complexes that ownπ-surfaces in its diimine ligands.(4) The correlations between EL performances and emitter's excited state lifetime are studied in detail. Our investigation leads to a conclusion that the too long excited state lifetime is one of the unrevealed limiting factors that not only isolate Eu-complexes from high efficiency but also from high brightness. Solution to this problem has been theoretically figured out and experimentally confirmed.(5) We report two easily synthesized RE(III) based emitters and their elementary applications for Fe(III) detection. Results suggest that RE(III) based emitters exhibit good spectral responses and ion selectivity towards Fe(III), as well as their excellent characters of oxygen insensitivity, making them promising candidates to be utilized in the actual applications.
Keywords/Search Tags:metal complex, photophysical properties, emission spectrum, excited state lifetime, Fe detectors
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