Synthesis And Photo/electro Luminescence Property Study Of A Series Of Novel Cationic Iridium(Ⅲ) Complexes

With the development of society, information plays an increasingly important role inpeople‘s lives the display device is undoubtedly an important way in the process of people toget information. So, display as an information carrier is an essential part of informationacquisition. By the growing demand for display equipment, the high-quality image, as well asportable flat panel displays will become the best choice of people in the21st century.Therefore, the study of higher performance, lower cost display devices has become one of thekey content of the various countries’ scientific researchers.The solid-state light-emitting electrochemical cell （LEC） as third-generation flat-paneldisplay technology is getting much attention by national researchers relying on excellentperformance. The applications of phosphorescent materials of metal complexes in LECgreatly improve the efficiency of the device, and the transition metal iridium complex is oneof the best among them. The iridium complex has phosphorescent characteristics, the strongspin–orbit coupling effect of transition-metal atoms can result in efficient intersystemcrossing from the singlet to the triplet excited state. Hence, transition-metal complexes canharvest both triplet and singlet excitons, thus leading to high phosphorescence efficiencies,the photoelectric conversion quantum efficiency approaching100%within theory. So,transition metal iridium complexes has become a hot research content in electroluminescentlight-emitting field.In the transition metal iridium complexes, ionic iridium complexes as luminescentmaterials compared with neutral iridium complexes have many incomparable superiority,mainly as the followings: first, the synthesis condition of ionic iridium complexes is moremoderate and easy, usually with higher yield and simple procedure of product purification;Second, the excellent redox reversibility of ionic iridium complexes help to improve devicestability; third, air-stable electrodes, such as gold, silver or aluminium, can be used in LECs toget efficient device; at last, due to the ionic iridium complexes carry charge and a counter ionPF6-, it is conducive to charge transport, carrier injection and transpot, consequently reducedevice power consumption. Therefore, the ionic iridium complexes as a kind of luminescentmaterial would have a huge potential and market prospect.The main researching contents of the paper are as follows:1. To reduce the size of the light-emitting materials in order to facilitate carrier injectionand transport, design and synthesis of five new ionic iridium complexes,[Ir（dfppz）₂bpy]⁺（PF6）^-,[Ir（dfppz）₂ttpl]⁺（PF₆）^-, Ir（dfppy）₂ttpl]⁺（PF₆）^-,[Ir（dfppz）₂pmz]⁺（PF₆）^-,[Ir（dfppz）₂bpcf₃]+（PF₆）^-, where dfppz, dfppy, bpy, ttpl, pmz, and bpcf3are1-（2,4-Difluorophenyl）-1H-pyrazole,1-（2,4-Difluorophenyl）-1H-pyridine,2,2’-bipyridine, 1,4,8,9-tetraquinoline phenanthrene amine,2-pyridyl-1-phenyl-benzimidazole, and2-Pyridin-2-yl-1-（3-trifluoromethyl-phenyl）-1H-benzoimidazole, respectively. All the ioniciridium complexes are characterized by IR, NMR, single crystal structure and othercharacterization.2. We studied the photoluminescence properties of thoes complexes, and explained therelationship between the structure and the photophysical properties of iridium complexes byquantum chemical calculations and electrochemical measured, simultaneous determined theexcited state lifetime and fluorescence quantum efficiency.3. LEC devices are fabricated to study the electroluminescent properties using these fivecomplexes. Their performance, such as lifetime, efficiency, CIE coordinate, turn-on time and maximumbrightness and so on, were investigated, then we studied the influence of the structure of iridiumcomplexes on device performance.