Synthesis, Structures and Application of Multifunctional Phosphorescent Copper(I) Complexes
|School||Lanzhou Jiaotong University|
|Keywords||Synthesis Copper(Ⅰ) complex Crystal structure|
Since the1950s, the organic light-emitting materials had been understandedpreliminarily. And luminescent material gradually showed its advantages, especially, they areused in organic light-emitting diodes （OLEDs）. OLEDs are considered as the latest newgeneration flat panel display technology of full color concurrently, low energy consumption,wide sight angle, quick response at the same time, and now it is in the process ofindustrialization. With the rapid development of science and technology and the progress ofhuman society, the light-emitting materials display all kinds of information which isdeveloping rapidly, and the light-emitting materials are needed to develop to meet thediversified requirements.Since the heavy metal complexes were used as phosphorescent dopants in highlyefficient OLEDs by Forrest, the utilization of the triplet energy through phosphorescentmaterials has been attracted vast attentions recently. Most of the complexes are mainlycomplexes of noble metal ions such as iridium（III） and Platinum（II） due to their high quantumefficiency, brightness, color diversity and short excited-state lifetime. Compared with thesenoble metal ion complexes, the copper（Ⅰ） complexes have the advantages of less toxic, lowcost, environmental friendliness, the diverse structures and abundant physical chemicalproperties, as well as good luminous efficiency. The copper（Ⅰ） complexes have been gottenthe extensive research and application. In this thesis, we synthesized some phosphorescentCu（Ⅰ） complexes which are highly efficient phosphorescence materials. It helps us tounderstand the application of phosphorescent Cu（Ⅰ） complexes in organicelectroluminescence.In the second part of the thesis, a new2-（2′-pyridyl）benzimidazole ligand （L） in which2-（2′-pyridyl）benzimidazole is linked to a4-（9H-carbazol-9-yl）phenyl fluorophore by amethylene spacer and two new mononuclear Cu（Ⅰ） complexes containing hole-transportingcarbazoly moiety,[Cu（L）（DPEphos）]（BF4） and [Cu（L）（PPh3）2]（BF4）, were synthesized andcharacterized by1H NMR and IR. The single crystal X-ray diffraction study of the Cu（Ⅰ）complexes reveal that the center Cu（Ⅰ） ion assumes highly distorted tetrahedral geometry. Andthe complexes exhibit strong orange emission in the solution and solid state at roomtemperature. In the third part, a new2-（2′-pyridyl）benzimidazole ligand （L） in which2-（2′-pyridyl）benzimidazole is linked to a1-(4-（5-（4-tert-butyl phenyl）-4-oxadiazoles-2-1）phenyl fluorophore by a methylene spacer and two new mononuclear Cu（Ⅰ） complexescontaining electronic-transporting oxadiazole group were synthesized and characterized by1HNMR and IR. The single crystal X-ray diffraction study of the Cu（Ⅰ） complexes reveal that thecenter Cu（Ⅰ） ion assumes highly distorted tetrahedral geometry. In the fourth and fifth parts,two dendritic ligands and their mononuclear Cu（Ⅰ） complexes were synthesized and characterized by1H NMR and IR. And the complexes exhibit strong orange emission in thesolutions.In order to study electroluminescent properties of the compound [Cu（L）（PPh3）2]BF4and[Cu（L）（DPEphos）]BF4, we used doping method by which the gest was doped in host materials.Mass fraction is5%,8%,12%and15%, respectively, that doped in the host CBP, Theelectroluminescence devices using the Cu（Ⅰ） complexes as dopant were fabricated, the devicestructure was ITO （150nm）/MoO3（2nm）/NPB （40nm）/CBP: Cu （Ⅰ） complexes （30nm）/BCP（30nm）/LiF （1nm）/Al （150nm）.The EL emission peak of [Cu（1L）（DPEphos）]BF4is located at590nm, the performanceof the electroluminescence device at the concentration of0.8wt%was the best. And the openvoltage is8V, when the voltage is12V, its maximum brightness is the3500cd.m-2.The EL emission peak of [Cu（1L）（PPh3）2]BF4is located at585nm, the performance ofthe electroluminescence device at the concentration of15wt%was the best. When the voltageis19V, the maximum brightness is375cd.m-2.The EL emission peak of [Cu（2L）（DPEphos）]BF4is located at560nm, the performanceof the electroluminescence device at the concentration of15wt%was the best. The openvoltage is7V, when the voltage is14V, its maximum brightness is2400cd.m-2.