三-（2，4，6-三氯苯）甲基自由基的苯并含氮杂环化合物的修饰、合成及其光电性能研究

发布时间：2018-03-19 14:20

本文选题：有机电致发光　切入点：开壳分子　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：在有机电致发光器件(OLEDs)三十年的发展历程中,大量的发光材料被设计、开发、报道出来。尽管这些分子的结构各式各样,但总结归纳起来基本都可以划归为四类体系:1.利用单线态激子发光的传统荧光材料体系;2.利用三线态激子发光的磷光材料体系;3.利用三线态激子转化为单线态激子的新型荧光材料体系,这其中包括:TTA、TADF以及HLCT材料体系;4.利用三线态激子与极化子作用转化成单线态激子的TPI材料体系。而不同于上述所有的发光材料体系,2015年,我们组开创性地提出一种利用双线态激子发光的机制,并首次利用一个开壳自由基分子TTM-1Cz(咔唑与TTM的加合物)做发光层,实现了较高效率的近红外电致发光。对于开壳自由基分子,其前线轨道(SOMO)上只有一个单电子,所以当分子受到激发后,单电子跃迁到更高的能级轨道,其原来所占据的轨道就会变为空轨道,这时,电子往基态的跃迁就会变为完全允许的。因此,从理论上讲,基于开壳分子的有机发光器件,其内量子效率可以达到100%。但是,可以在空气中稳定存在的自由基种类比较受限,而能够室温发光的自由基分子就更为稀少;另一方面,由于自由基本身的性质,该类发光材料体系的发射基本都在深红/近红外区。因此,设计开发更多稳定的发光自由基,丰富该类材料体系以及调控分子的发射波长使其覆盖更宽的波长范围,是一项很有意义而又富有挑战性的工作,而且对于此类材料体系的研究仍有大量基础工作需要开展。本论文依据双线态激子的发光机制,基于稳定中性的三-(2,4,6-三氯苯)甲基自由基(TTM)衍生物具体开展了以下两部分内容的工作:1.基于TTM和给电子含氮杂环吲哚单元的修饰合成及光电性能研究。我们选取给电子含氮杂环吲哚分子作为修饰单元,同时注意到吲哚虽然比咔唑的给电子能力略强,但是分子结构上少一个苯环会导致共轭程度明显降低。我们将吲哚连接到TTM苯环的对位碳上,合成出具有不同取代基数目的TTM-1ID和TTM-2ID。两个分子具有明显的分子内电荷转移(ICT)性质,它们的发射光谱相比TTM红移,相比TTM-1Cz蓝移。两个材料的电致发光(EL)波长都在650 nm左右,并且获得了在不同电压下都比较稳定的光色。CIE坐标分别为(0.649,0.306)和(0.667,0.301),接近美国国家电视标准委员会(NTSC)制定的红光标准。器件的最大外量子效率分别为1.8%和2.4%,尤其是基于TTM-2ID的电子器件,其双线态激子生成比例达到了接近100%的水平。然而,两个分子较低的薄膜荧光效率限制了器件性能的进一步提高。2.基于TTM和拉电子含氮杂环苯并咪唑的修饰合成及光电性能研究。出色的器件性能需要能同时具备高发光效率和高激子生成比例的发光材料。所以在第二部分工作中,我们选取常见的吸电子基团苯并咪唑作为修饰单元,制备合成了两个新颖的具有不同取代基数目的开壳自由基分子TTM-2Bi和TTM-3Bi。我们通过抑制分子的ICT程度,既调控了发光波长的进一步蓝移,同时又大大提高了其掺杂薄膜的光致发光效率。基于两个材料的掺杂器件都展现出了出色的稳定性和抗电压击穿特性。两个器件的最大外量子效率分别达到了5.4%和4.1%,尤其是基于TTM-2Bi的电致发光器件,其最大外量子效率更是超过了传统荧光OLED外量子效率5%的理论上限,两个器件的激子生成比例也分别达到了69%和57%。
[Abstract]:In organic electroluminescent devices (OLEDs) thirty years of development, a large number of luminescent materials was designed, developed, reported. Although the structure of every kind of these molecules, but summarized up basically can be divided into four categories: 1. system singlet exciton emission of the traditional fluorescent material by three line system; 2. exciton emitting phosphorescent material system; 3. by three excitons into new fluorescent material system of singlet excitons, which include: TTA, TADF and HLCT material system; 4. using three excitons and polaron effect into singlet exciton TPI material system. Different from all of the above luminescent materials the system, in 2015, our group put forward a double use state exciton luminescence mechanism, and use an open shell free radical TTM-1Cz first (carbazole TTM adducts) as the emitting layer to achieve a more Near infrared light emitting efficiency. For open shell molecules, the frontier molecular orbital (SOMO) only a single electron, so when the molecule is excited by single electron transition, to a higher level of its original track, occupy the track will become empty track, then the electronic transitions will go the ground becomes fully allowed. Therefore, theoretically, organic light emitting devices based on open shell molecules, the internal quantum efficiency can reach 100%. but can free radicals are stable in the air is limited to free radicals at room temperature luminescence is even more scarce; on the other hand, because of the basic properties of the free body, the light emitting material system of emission basically in the red / near-infrared region. Therefore, the design and development of more stable emission free radicals, rich the material system and molecular emission wavelength to cover a wider wave Long range is a meaningful and challenging work, and Research on this material system still has a lot of work needs to be done. This paper is based on the double exciton luminescence mechanism, based on stable neutral three - (2,4,6- three -) methyl radical (TTM) derivatives as follows two part of the contents of the work: 1. based on TTM and electron heterocyclic indole unit modified synthesis and photoelectric properties research. We selected for electronic heterocyclic indole molecules as the modified unit, noting that although the electron than indole carbazole ability stronger, but less on the molecular structure of a benzene ring will lead to obvious degree of conjugation we will be reduced. Connect to the TTM indole para carbon benzene, synthesized with different substituents to TTM-1ID and TTM-2ID. two molecules with obvious intramolecular charge transfer (ICT) properties of it The emission spectra of TTM compared with redshift, compared to the TTM-1Cz blue shift. Two el (EL) wavelength around 650 nm, and obtained the.CIE color coordinates in different voltages are relatively stable respectively (0.649,0.306) and (0.667,0.301), close to the United States National Television Standards Committee (NTSC) red standard. The maximum external quantum efficiency of the device were 1.8% and 2.4%, especially in electronic devices based on TTM-2ID, the double exciton generation has reached a level close to 100%. However, the film fluorescence efficiency of two molecules of lower limit device to further improve the performance of.2. modified synthesis and photoelectric properties of TTM and electron withdrawing nitrogen containing heterocyclic benzimidazole based on devices with excellent performance. It can also have the luminescent materials of high luminous efficiency and high exciton generated proportion. So in the second part, we choose common The electron withdrawing groups as modified benzimidazole unit, has synthesized two novel with different substituents to open shell radicals TTM-2Bi and TTM-3Bi. inhibited us by ICT molecules, which regulate further blue emitting wavelength shift, but also greatly improves the efficiency of the light emitting light. Based on doped doped thin films device two materials showed excellent stability and anti voltage breakdown characteristics. The maximum external quantum efficiency of two devices respectively reach 5.4% and 4.1%, especially TTM-2Bi electroluminescent devices based on the maximum external quantum efficiency is more than the theoretical upper limit of traditional fluorescent OLED external quantum efficiency of 5%, exciton the proportion of the two generation devices are respectively 69% and 57%.

【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O626

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