Synthesis Of Iridium Complexes Based On Double Chromophores And Their Properties In White Light-emitting Devices

The white organic light-emitting devices（WOLEDs）have a broad application prospect in flat panel display and illumination,and have become a hotspot rencently.This paper systematically summarizes the research status of organic light-emitting materials and WOLEDs in recent years.Aiming at the difficulty in molecular and low device efficiency of organic single-molecule white light materials,the wide spectral emission is obtained by changing the auxiliary ligand structure in this paper.And a series of single-nuclear and di-nuclear phosphorescent iridium complexes with double chromophores were designed and synthesized.The structured-property relationship,thermal stability,photophysical properties and electroluminescent properties of these complexes are discussed in detail.The main research contents and results are as follows:1.Using naphthalene pyridine（npy）and phenyl isoquinoline（piq）as C^N auxiliary ligands,we designed and synthesized single-nuclear iridium complexes（2Fppy）₂Ir（npy）and（2Fppy）₂Ir（piq）.At the same time,using 5-methoxypyrazine-2-carboxylic acid（5-OMepzic）and 3-methoxypyrazine-2-carboxylic acid（3-OMepzic）as O^N auxiliary ligand,we designed and synthesized single-nuclear iridium complexes（2Fppy）₂Ir（5-OMepzic）and（2Fppy）₂Ir（3-OMepzic）.The results show that introducing different C^N or O^N auxiliary ligands into iridium complexes is beneficial to regulate intramolecular energy transfer.By means of device optimization,WOLED with CIE color coordinate of（0.320,0.364）can be obtained,and it’s maximum external quantum efficiency is 6.58%.2.In order to further explore the mechanism of intramolecular energy transfer,the mononuclear iridium complex in Chapter 1 was connected by non-conjugated groups,and a di-nuclear iridium complex（2Fppy）₂Ir（pzic）-5-C₄-3-（pic）Ir（2Fppy）₂ was constructed.The results show that the di-nuclear iridium complexes can effectively obtain white emission due to incomplete intramolecular energy transfer.The doped WOLED with CIE color coordinate of（0.246,0.411）can be obtained,and it’s maximum external quantum efficiency is 9.91%.