The Synthesis, Electronical Structure And Photoelectric Properties Of Some Bipyridine Ligands And Their Metal Complexes

In passed decades, major breakthroughs have led to significant improvements inthe performance of organic light-emitting devices (OLEDs) due to the use ofelectrophosphorescence metal complexes, while new materials with better propertiesare still needed to fully realize the advantages that organic and polymer LEDtechnology can potentially offer, for example, the complexes with properties adjustedeasily. The transitional method to fabricate OLEDs based on electrophosphorescencemetal complexes is doping them into host polymers to decrease their concentrationquenching. But even though there is concentration quenching at low concentration ofelectrophosphorescence metal complexes, which is due to their phase separation.Incorporating electrophosphorescence metal complexes into the host polymers is aneffective way to resolve this problem. Because the chemical bond of the polymer andelectrophosphorescence metal complexes can decrease the phase separation and theenergy between them is more efficient. But for part of these materials, incorporatingmetal complexes into polymer backbone, the emissive efficiencies are too lower tocompared with the molecule doping system. And the reasons are not studied clearly.Further, by using the polymer's incorporating with different metal ions, theinteraction between polymers and metal ions can be studied. In Chapter 3, by changing α,α'-diimine ligands of (L)Re(CO)3Cl · iii ·吉林大学博士学位论文 中英文摘要(L=2,2′-bipyridine, 1,10-phenanthrling and so on), we synthesized a series of Recomplexes which feature strong metal-to-ligand-charge-transfer (MLCT), studiedtheir photophysical properties and fabricated LEDs based on them. Thephotophysical properties results show the changing L ligands cause the LUMO andHOMO changing of Re complexes. Further, the quantum chemistry calculation andthe electrochemistry studies provide the changing LUMO and HOMO in detailaccording to different L ligands. This is helpful for the molecular design to fulfill theapplication of full color display based on Re complexes. And the performances oftheir applications in LEDs are gratifying: the maximum luminance is 3686 cdm-2 andthe maximum luminescence efficiency is 7.15 cd A-1. Moreover, the efficiencyremained a high level at high brightness and current density. In Chapter 4, we synthesized new Re complexes, whose ligands are conjugatedpolymers, and stud ied their properties. Changing the small molecular ligands of Recomplexes by conjugated polymers, the photoluminescecnce (PL) andelectroluminescence (EL) efficiency of Re complexes decreased, though thecharacterizing metal-to-ligand-charge-transger (MLCT) of Re complexes can beobserved at room temperature. Another competitive results of light emitting,photo-induced change separation, can be observed. We consider that the lower PLand EL efficiency of these phosphorescent metal complexes incorporatingπ-conjugated polymer system is conceivably related to charge carrier separation oflocalized electron-hole pairs (excitions) in (bpy)Re(CO)3Cl complexes, which isinduced by extensive π-conjugation. Further, the calculations on the electronicground state of (bpy)Re(CO)3Cl and surface photovoltaic spectra provide the prooffor charge separation in the chelating polymer systems. And this implies a newpotential application for the conjugated polymers containing Re complexes inbackbone. · iv ·中英文摘要 吉林大学博士学位论文 In Chapter 5, by incorporating different metals into the polymer P1/P2backbone, we study the interaction between polymers and metal ions. The interactionbetween P2 and metal ions indicated a new kind of materials used as metal sensingmaterials and the practical application of metal sensing c...