【作者】 任雪峰；

【导师】 任爱民；

【作者基本信息】 吉林大学 ， 物理化学， 2010， 博士

【摘要】 有机电致发光材料一直是国际上的一个研究热点。经过多年的研究,开发纯度高和效率好的红光发光材料依然是国内外科研工作者努力的方向,本文从开发和设计新型高性能的红光材料的角度出发,采用现代量子化学理论计算方法,研究了三种类型的红光材料的电致发光性能,包括这些化合物的基态和激发态的平衡几何结构、前线分子轨道、载流子的注入和传输、吸收和发射光谱,这为探索红色发光材料的结构-性质之间的关系奠定了理论基础,并且也为进一步开发高效率的红光材料提供了有价值的依据。研究工作主要包括以下三个方面的内容:1.研究了新型的具有化学键能量(TB)传递特性的卟啉衍生物的电子结构和光学性质。在对实验分子的研究基础上,理论设计了一系列的卟啉衍生物,首先验证这些分子是否存在TB能量传递特性,并进一步探索这类红光材料具有高效率的原因。2.研究了含有缺电子基团2-pyran-4-ylidene-malononitrile(PM)的低聚物的电子结构、载流子注入和传输能力、以及光谱性质。计算结果表明,引入PM基团可有有效的提高低聚物的电子注入能力,这为解决高效率的电子注入材料提供了一个有用的线索。3.研究了引入苯胺基团的数量和位置对Ir化合物的电子结构、载流子注入和传输能力以及光学性质的影响。计算结果表明,逐渐增加苯胺基团可以有效的提高空穴注入能力。并且在Ir的对位引入苯胺比在间位更有效。通过电离能(IP)、电子亲和势(EA)、重组能(λ)的研究,我们发现Ir-(g1′)3, g1′=N-(3-(2,3-dihydro-2-methylisoquinolin-1-yl)-4-methylphenyl)-N-phenylbenzenamine可以作为好的红色磷光材料。更多还原

【Abstract】 For full-color displays, three primary colors, i.e., blue, green, and red light-emitting materials are required. Green and blue light-emitting materials have al-ready met the requirements for commercial application. However, the red light-emitting materials with high brightness and efficiency are scarce. Nowadays, the rapid developments of science and technology have greatly contributed to the devel-opment of computational chemistry. Theoretical calculations show that by chemical modification the physical properties of materials could greatly be improved.In this paper, we systematically investigated three types of red emitting materials, including porphyrin relatives with through-bond energy transfer character, oligomer with electron-deficient group, phenylamine substitued Ir compounds, by quantum chemistry methods, namely, DFT, TDDFT, TDHF, CIS methods. We systematically investigated the ground state and lowest excited state conformations, frontier molecu-lar orbital, ionization potential (IP), electronic affinities (EA), reorganization ener-gies(λ), absorption and emission spectra. The theoretical study is intended to establish the structure-photophysical property relationship for designing efficient red emitters for OLEDs. The following is the main results:1. A series of porphyrin relatives with through-bond energy transfer character is investigated. The calculated results show that the TB energy transfer character has been detected in some extent by the analyses of electronic structure, frontier molecu-lar orbital and electronic spectra. Moreover, the reasons for their high efficiency as red emitting materials have been revealed by the investigations of the ionization po- tential (IP), electron affinity (EA), reorganization energy (λ), and exciton binding en-ergy (Eb). After introducing the 2-[thiophen-2-yl]thiophene to porphyrin-ring, the electronic injection and transfer abilities of porphyrin relatives are greatly enhanced. 5?10?15?20-tetra(carbazole)porphyrin(TCP) and Zn-5?10?15?20-tetra(carbazole) or-phyrin (ZCP) have faster carrier injection and transport rate, better carrier transport balance, and relatively smaller exciton binding energy than experimental sythesized molecules, rendering great potential of these red emitting materials with high fluores-cence quantum yield in the development of red OLEDs.2. A series of fluorene-based oligomers containing 2-pyran-4-ylidene malononitrile (PM) unit is investigated. The calculated results the electronic structure and photoproperties have been greatly improved by PM unit. It is found that the in-troduction of thiophene and 2-methoxyphenol in this type of copolymers have low-ered the LUMO energy, lifted the HOMO energies, and narrowed HOMO-LUMO gaps. Furthermore, Among these compounds, {2-[2-{2-[5-(9H-Fluoren-3-yl)- thio-phen-2-yl]-vinyl}-6-(2-thiophen-2-yl-vinyl)-pyran-4-ylidene]-malononitrile}n has de-creased IP, increased EA, and decreasedλhole values, suggesting that it is a excellent red emitting materials with high charge injection and transportation.The effect of phenylamine chromophore on the structure, optical properties, charge injection as well as charge transport features of a series of iridium(III) com-plexes is investigated. Our calculation results indicate that the hole injection ability have been greatly altered by the aromatic amine units. By introducing the diphenyl-amine unit, the contribution of 5d orbital from Ir center to the HOMO of both the ground and triplet states is decreased. From the consideration of IP, EA,λ, the pa-ra-substituted derivative Ir-(g1’)3 where g1’=N-(3-(2,3-dihydro-2-methylisoquinolin-1- yl)-4-methylphenyl)-N-phenyl benzenamine has great potential to serve as a high performance red triplet emitter.更多还原