Synthesis And Applications Of Double-nitrogen Heterocycle Iridium(?) Complexes In Oleds

During the recent three decades,organic light emitting diodes(OLEDs)have obtained much attention and are widely researched by public.More and more people begin to make research on the respect of improving the efficiency and brightness,etc.High internal quantum efficiency,high external quantum efficiency and low operating voltage are considered to be the most important consideration factor of high efficiency.It requires the good performance of light-emitting properties of the electron and hole transport of the electroluminescent materials.Pyridazine and pyrimidineare all n-type doped,theyboth have the advantages suchas high affinity nuclear potential,good electron injection and transport properties and high luminescence quantum efficiency.So they are widely applicated in OLEDs.Some cyclomedtalated ligands based on pyridazine or pyrimidine derivatives can improve the performance of complex phosphorescent materials.Therefore,a series of pyridazine,pyrimidine derivatives and their iridium(?)complexs have been designed and characterized in this master thesis.Besides,it makes future study on organic electroluminescent device.1.Synthesis and optical properties of novel pyridazine iridium complexes.A series of iridium(?)complexes based on pyridazine compounds containing ptericne structure with large steric hindrance have been successfully synthesized and characterized.Their structures are confirmed by 1H NMR,13C NMR,MODI-TOF and so on.A novel three-dimensional triptycene structure has been designed based on anthracene which as a raw material,and then obtained C ^ N ligands diphenyl pyridazine anthracene(ddpa)through a series of reactions,and synthesized corresponding tricyclic iridium(?)complexes Ir(ddpa)3 and different macrocyclic ligand complexes(ddpa)2lrpic and(ddpa)2IrTP.Their characterizations are measured by UV,PE and Cyclic voltammetry(CV).By introducing this new three-dimensional triptycene structure can obtain good luminescence yellow iridium(?)complexes,the reason is that increase the steric hindrance,reduce non-radiative transitions,inhibit the accumulation ?-? efficiency.Three kinds of iridium complex used as a triplet emitter doped in a polymeric host in solution processed electrophosphorescent light-emitting diodes.A maximum luminance of Ir(ddpa)3,(ddpa)2Irpic and(ddpa)2IrTP were 73957 cd/m2,36939 cd/m2 and 58511 cd/m2 respectively,while maximum current efficiency of 31.40cd/A(Ir(ddpa)3),24.92cd/A((ddpa)2Irpic))and 30.88 cd/A((ddpa)2lrTP)),a high-efficiency emission with maximum external quantum efficiency as high as 10.34%?8.22%and 9.13%.2.Blue iridium(?)complexes based on 2-chloro pyrimidine:synthesis,photo-physical properties.In this work,we have successfully synthesized a series of iridium(?)complexes bearing 2-substituted pyrimidine derivatives of C ^ N ligands and subsidiary ligand of 2-pyridine carboxylic acid,2-(3-(trifluoromethyl)-1H-1,2,4-triazole 5-yl)pyridine(TP)(called DFPIrTP,DFPIrpic,DFPOIrTP,DFSIrTP,DTFIrTP and DCIrTP).Their structures are confirmed by 1H NMR,13C NMR and MODI-TOF.The further photophysical properties are measured by UV,PL and electric chemistry.In our previous work,we found that introduce electron withdrawing group can adjust the complex emitting color blue-shift in a simple,efficient and inexpensive way,so we use boric acid with fluorine,compared to different number of fluorine atom.We also introduced a phosphine group to enhance the electron withdrawing ability,which the DFPOIrTP emission peak in methylene chloride solution at 455nm,have reached the pure blue requirements.It has great potential in blue light-emitting device application.3.Highly efficiency orange-red light-emitting devices iridium(?)complexes based on quinazolin derivatives for organic light-emitting diodesA novel iridium(?)complex(PQxD)2IrTP(HPQxD,N,N,2-triphenyl quinazolin-4-amine,TP,triazolate)was synthesized.Their structures are confirmed by 1H NMR,13C NMR and MODI-TOF.The further photophysical properties are measured by UV,PL and electric chemistry.Throng changing the ancillary ligands can improve the luminescence properties of complexes.We fabricated solution-processed electrophosphorescent light-emitting diodes using(PQxD)2IrTP as doping material.A maximum luminance of 31227 m-2 and a high-efficiency emission with maximum external quantum efficiency as high as 16.33%have achieved,compared with(PQxD)2Irpic,the brightness of(PQxD)2IrTP has improved nearly 5 times.