Study On Synthesis And EL Performance Of Irdium Complexes With Fpypy Ligands

In recent years, a new generation of organic optoelectronic full-color display and solid-state lighting technology has made a major breakthrough in the industry and the scientific community. The products are widely applied to flat panel displays on mobile phones, televisions, and smart watches. The materials of all color in the visible region as red, yellow, green and blue has started industrial application. Discovery and application of the phosphorescent material greatly improves the device efficiency, internal quantum efficiency(IQE) close to 100%(theoretical value) materials have been achieved, yet less energy and more obvious advantages in industry applications. But deep blue phosphorescent materials are still scarce, resulting in high efficiency deep blue phosphorescent devices(CIEx~0.15, CIEy~0.10) to be developed more difficult. Excellent deep blue phosphorescent materials are greatly significant not only for the full-color display but also the organic solid-state lighting technology. Therefore, the design and synthesis of new blue phosphor materials is greatly significant for full-color organic photoelectric display industry. The main contents of this paper are designed, synthesized and properties investigated of the phosphorescent six-coordinate complexes of iridium complexes containing 2’,6’-difluoro-2,3’-bipyridine(dfpypy) and applied in deep blue and deep red phosphorescent organic light emitting device.In the second chapter, dipcca fptz we synthesized four six-coordinate iridium complexes bassed on dfpypy as the first ligand and dipcca, fptz as the second ligand. We analysised their bond lengths, bond angles and the characteristics of the molecular structure in the view of microscopic through the crystal structure, at the same time, discussed on the molecular accumulation and the inter-molecular force. There are no apparent molecular π-π force and intermolecular hydrogen bond among the three molecules Ir1, Ir2 and Ir3, but only the intermolecular van der Waals force, they are very rigid molecules, which of great significance to reduce the exctions concentration quenched and improve the luminous efficiency for the moleculars in phosphorescence devices.In chapter 3, we analyze and character the physical property of Ir1 and Ir2, thermodynamic properties of the complexes showed good thermal stability and not prone to crystallization in high temperature deposition process that result well suited for organic thin film evaporation in a vacuum. Photophysical properties tests show the fluorescence emission exhibited their intrinsic blue emission in different contexts(solution, low-temperature 77 K and doped films). Their HOMO-LOMO frontier, orbital distribution of orbital energy band gap and other issues from the oretical calculation indicate that the compounds having a wide band gap and provide a basis for the work of making the device. Then we develop phosphorescent light-emitting devices with Ir1 and Ir2 as the light-emitting layer result in deep blue light emitting(0.10 <CIEy <0.15). The device turn-on voltage is only 3.5V, the maximum power efficiency and maximum external quantum efficiency are up to 10 lm W-1 and 10% or more.In chapter 4, we analyze and character the physical property of the complexes FPYPCA, BTPBA and BTIPG, thermodynamic properties of the complexes showed very suitable for organic thin film evaporation in a vacuum. There is a greater overlap between the absorption spectrum of BTPBA and BTIPG and the emission spectrum of FPYPCA seen from the photophysical properties. Electrochemical properties and theoretical calculations both show that FPYPCA has high triplet energy level(T1) and narrow band gap(Eg) as the subject for red phosphorescent object material. Also FPYPCA is very suitable for hostmaterial as bipolar and high and balanced carrier transport capability which showed from theory simulation and time of flight(TOF). Then we developed a phosphor–phosphor type(PPT) doped Ph OLEDs which exhibited stable deep-red emitting color and the constantly high EQE values of 23% at the rather high and wide luminance range of 1000--10000 cd m-2. There are many advantages in terms of easy charge injection, balanced charge fluxes and efficient host–guest energy transfer, compared with conventional emitting cases based on the fluorescent host such as CBP.