【作者】 辛倩；

【导师】 陶绪堂；

【作者基本信息】 山东大学 ， 材料学， 2008， 博士

【摘要】 有机电致发光器件具有全固化主动发光,亮度高,视角宽,对比度高,超薄,功耗低,响应速度快以及柔性可弯曲折叠等优点,已被视为继CRT（阴极射线管）,LCD（液晶显示）之后最有前途的“第三代显示技术”,可广泛应用于平板显示及照明等领域。材料是器件的物质基础,发光材料作为有机电致发光器件中最终承担发光功能的物质,对于器件的性能有着至关重要的影响。有机发光材料的性能在很大程度上决定了有机发光器件的发展和实用化进程。从这种意义上来说,研究与探索高效荧光材料,特别是在固态下的强发光材料具有重要的理论与实际意义。Tr（o|¨）ger’s Base（TB）是一个有一百多年历史的老化合物,但近年来,由于超分子化学的发展,TB及其类似物又成为研究热点,主要是因为这类化合物本身固有的刚性、手性、Λ-型腔状结构特性和在现代科技领域里的广泛应用前景。本论文正是基于TB类化合物特有的这种刚性Λ-型扭转构型,理论上由于空间位阻作用不利于形成易引起“固态荧光淬灭”的π-π密堆积,从有机光电材料的角度出发,首次设计并合成了一系列具有大π共轭芳香侧翼的芴基与蒽基Λ-型TB类化合物TBFB,TBFB-Br,TBF-Br,TBFB-MP,TBFB-BP,TBFB-FB,TBFB-TPA及TBA。研究表明这一系列新颖的芴基与蒽基TB类化合物不同于容易产生“固态荧光淬灭”现象的传统有机发光材料,在固态下具有强荧光。同时,本论文详细研究了这一系列新的Λ-型TB类化合物的晶体堆积工程,主体包合性能,热学稳定性能,聚集态有序度及形貌,电化学性能与光物理性质,并探讨了结构与性能之间的关系。晶体是物质存在的最基本形态,了解晶体中分子结构和分子的堆积状态,对于研究物质与物理性质之间关系具有重要的指导意义。本文通过混合溶剂缓慢渗透挥发法,生长出六个新的TB类化合物的单晶（TBFB,TBFB-Br,TBF-Br,TBFB-BP,外消旋-TBA和右手旋光（S,S）-TBA）与两个包合物晶体（TBFB-MP·p-xylene与（TBFB-MP）₂·EtOH）,并通过X-射线衍射解析了它们的晶体结构。通过对晶体结构进行分析,得出以下结论:这类芴基、蒽基TB类化合物的分子都具有两个结构基元:中心的Λ-型桥与一对刚性的π-共轭芳香侧翼。芳香π-共轭侧翼为分子间潜在的面面（OFF）与边面（EF）相互作用提供了节点;Λ-型桥头N原子为C-H…N相互作用提供了潜在的节点。本论文还详细分析讨论了卤素溴取代基与烷基取代基（正丁基）对芴基TB类化合物晶体堆积结构及分子间作用力的影响,以及取代基效应与手性拆分对于TB类化合物包合客体潜能的影响。实验结果表明溴取代基的引入有利于增强芴基TB类化合物的包合潜能,且烷基的同时引入也可以辅助增强这种溴取代芴基TB类化合物的包合潜能;具有适当取代基（溴,对甲苯基）的TB类化合物TBFB-Br,TBF-Br,TBFB-MP及完成手性拆分后的右手旋光（S,S）-TBA显示出潜在的主体包合性能与多孔储气性能,并且我们成功制备了关于TBFB-MP的两个包合物晶体。研究表明我们合成的新型TB类化合物不仅在溶液中具有高的荧光量子产率,而且固态下具有优异强发光性能,同时具有很好的热稳定性与形态稳定性,真空热蒸镀均可获得平滑连续无针孔的无定形薄膜,满足制备光电半导体器件的使用要求。我们从紫外吸收,光致发光,荧光量子产率,荧光寿命,轨道能级等方面系统表征了这类材料的光物理与电化学性能,并结合晶体结构,讨论了结构与性能的关系,从理论方面进行了合理的分析与解释。研究表明侧翼为芳基取代芴基及蒽基的TB类化合物在溶液及凝聚态下均表现出非常强的荧光,由于Λ-型TB骨架的引入,没有出现传统发光材料的固态荧光淬灭现象。同时本论文还首次发现了TB类材料在不同聚集态下,多晶粉末较无定形薄膜发光蓝移的特殊现象。这是因为这类化合物的刚性与Λ-型TB骨架空间位阻作用,使得分子在晶态下由于受在晶格中严格的定向排列的限制,排列较为疏松;而无定形薄膜中分子可以较为自由地排列,使得分子能够排列地更为紧密从而增强了分子间相互作用力所致。本论文还初步探索了这一系列TB类化合物在电致发光领域的应用,优选其中五个固态光致发光性能优异的化合物TBFB-MP,TBFB-BP,TBFB-FB,TBFB-TPA与TBA作为主体发光层制备了简单的三层电致发光器件,器件结构为:ITO/NPB（30nm）/TB analogue（40nm）/TPBI（40nm）/LiF（1nm）/Al（80nm）,测试结果表明这类TB类化合物显示出了高效（0.38-2.59cd/A,0.73-2.781m/W）、高亮（4774-27685cd/m²）、低驱动电压（3.2-5.3V）的蓝色或绿色电致发光。尤其TBFB-BP与TBFB-FB具有非常好的综合电致发光性能,结合其简单易行的合成路线,提纯与薄膜制备工艺,是极有希望工业化生产的高效蓝色电致发光材料。电致发光器件性能表明Λ-型TB类化合物具有巨大的电致发光应用潜能,是一类新的极具竞实力的电致发光材料。总之,从化合物的设计,到合成表征、晶体结构的解析、性质的测试、结构与性能的关系以及最后的电致发光器件的制作与表征,我们对新型芴基、蒽基Λ-型TB类化合物进行了系统的研究,初步证实了这类材料在超分子化学领域潜在的主体包合性能与存储气体性能,得到了几个新的多孔晶体材料与两个包合物晶体材料,并首次成功的将TB类化合物应用于电致发光领域,得到了高效、高亮、低压驱动的蓝色、绿色电致发光,开辟了TB类化合物的一个新的应用领域。此外,我们关于这类新型发光材料的设计理念——将大π-共轭芳香体系引入Λ-型TB骨架侧翼,将会指导我们开发更多性能优异的新型TB类发光材料。更多还原

【Abstract】 Organic Light Emitting Diodes （OLEDs） are advantages in that they are self-luminous, high-brightness, wide viewing angle, high contrast, thinness, low power consumption, fast response time and flexibility and are leading next-generation technologies for electronic displays and lighting.As the key components of OLEDs, the development of organic light-emitting materials limits the practaical use of OLEDs to a great extent. In this sense, to study and explore highly efficient fluorescence materials, especially those strongly emissive in the solid state, would be of great importance in both theory and practice.Although Troger’s base （TB） has been known for 120 years, recently, as the rapid development of supramolecular chemistry TB analogues have attracted renewal attention due to their particular rigid, concave∧-shaped chiral nature and potential applications in fields of molecular recognition, DNA interactions and clathrate host materials. Considering that this particular rigid and∧-shaped twisted configuration of TB analogues, which is theoretically disadvantageous for the formation ofπ-πclose stacking, which may lead to fluorescence quenching in the solid state, we have designed and synthesized a series of new∧-shaped fluorene or anthracene based TB analogues TBFB, TBFB-Br, TBF-Br, TBFB-MP, TBFB-BP, TBFB-FB, TBFB-TPA, TBA and a condensed rings compound DAP. Their crystal engineering, host including properties, thermal stabilities, aggregated states orders and morphology, electrochemical properties and photophysical properties are examined in detail for photonic applications.Crystal structure is very important for the study of the relationship between the compounds and physical properties. Six new TB analogues （TBFB, TBFB-Br, TBF-Br, TBFB-BP, racemate-TBA and （S,S）-TBA） crystals and two inclusion crystals （TBFB-MP·p-xylene and （TBFB-MP）₂·EtOH） are obtained by cosolvents- pervading and evaporating method, and these crystal structures were investigated by X-ray diffraction. The results confirmed that these TB analogues involve two molecular units: two aromatic wings and a central methylene diazocine bridge. The aromatic wings of these TB analogues provide sites for potential aryl offset face-face （OFF） and edge-face （EF） interactions and the N atoms on the central bridges provide sites for potential C-H…N interactions. We have also analysed and discussed the effect of the substituted n-butyl and bromine groups on the crystal packing structure and the intermolecular interactions, as well as the substitution effect and effect of chiral separation on the the inclusion potential of the TB analogues. Our results indicated that TB analoges with appropriate substitutions （eg. bromine, tolutyl）, such as TBFB-Br, TBF-Br, TBFB-MP and right hand chiral （S,S）-TBA possess host inclusion properties and gas-storing potentials, and we have also obtained two inclusion crystals of TBFB-MP.Our results indicated that these new TB analogues not only show high fluorescence quantum yields in dilute solutions, but also show strong photoluminescence in the solid state. These compounds also have high thermal stability. The vacuum sublimated films of these TB analogues are continuous, smooth and amorphous. These advantages make these compounds fullfil the requests of the semiconductor devices. We have characterized the photophysical and electrochemical properties of thse TB analogues by UV-vis absorption spectra, Photoluminescence spectra, fluorescence quantum yields, fluorescence lifetime and orbital levels （HOMO and LUMO levels） and discussed the relationships between the crystal structures and properties of these compounds. We observed that fluorene-based TB analogues with aryl substitutions （TBFB-MP, TBFB-BP, TBFB-FB and TBFB-TPA） and anthracene based TB analogue （TBA） exhibit strong fluorescence emission both in dilute solutions and aggregated states. Some abnormal photophysical behaviors for TB analogues have been observed; that is, the emissions of the amorphous film are obviously red-shifted in comparison with that of the polycrystalline powders, since a possibly denser packing of the molecules in the amorphous state that strengthened the intermolecular interactions.The light emitting properties of the fluorene and anthracene based TB analogues have also been explored. Organic light emitting diodes （OLEDs） using five TB analogues （TBFB-MP, TBFB-BP, TBFB-FB, TBFB-TPA and TBA） as non-doped emitters with device structure of ITO/NPB （30nm）/TB analogue （40nm）/TPBI （40nm）/LiF （1nm）/Al （80nm） were fabricated and high brightness （4774-27685cd/m²）, high efficiency （0.38-2.59cd/A, 0.73-2.781m/W） and low turn-on voltage （3.2-5.3V） were obtained. Expecially, TBFB-BP and TBFB-FB show excellent integrate electroluminescent properties with blue emission. Our studies suggested that TB analogues could be excellent light emitting materials for OLED applications.In summary, systemic analyses and discusses about the new fluorene and anthracene based TB analogues have been done by us. The studies included the molecular design, synthesis, characterization, crystal structure, OLEDs using TB analogues as emitters and relationships between the structures and properties. The results indicated that these compounds hold large potentials in the host including chemistry field and gas-storing field, and we have also obtained several new porous crystal materials and two inclusion crystals. Furthermore, we have successfully used the TB analogues as host electroluminescent materials, and obtained blue or green emissions with high efficiency, high brightness and low driving voltage. Our studies suggested that TB analogues could be excellent light emitting materials for OLED applications. In addition, the method of material design, introducing∧-shaped TB scaffold and large conjugated wings to the molecules, can also be applied in the design and synthesis of efficient TB analogues emitters containing other aryl groups in the wings.更多还原