新型对称含咔唑类发光材料的合成及性能研究

发布时间：2018-05-01 09:16

  本文选题：合成 + 咔唑　； 参考：《长春工业大学》2017年硕士论文

【摘要】：咔唑具有稳定的平面共轭刚性结构,结构中氮原子含孤对电子是一种稠环结构的化合物,同时咔唑基团是一种具有优良光电性能的基团。其不仅光热稳定性良好,还能进行多位点的化学反应。将咔唑设计于光电功能材料中,不仅能保证其具有良好的光电性能,也可扩展科研人员对化合物的设计思路。当前对于咔唑基团的研究与利用是通过共轭的方式引入到主链中,或以不同的聚合方式将咔唑引入聚合物链中形成高分子聚合材料等。将咔唑以烷基链的方式结合到目标化合物中研究的则比较少。由于烷基链连接的咔唑基团具有给电子的特性,其中咔唑本身又具有光电性质和电荷传输性能,使得这类材料在光电材料领域应用潜力巨大。溶解度在有机发光材料中是一个很重要的条件,在化合物中引入烷基链可以有效的提高溶解度还可以促进高质量的薄膜沉积。光电器件的稳定性和寿命关键在于化合物的热稳定性。咔唑衍生物是一类强的蓝色光发射、高Tg温度和热稳定性效应的化合物,使它们成为OLED设计有吸引力的候选者。本文设计合成三种含有不同长度烷基链具有较强的蓝色发光性和高稳定性的咔唑衍生物。并利用DSC、TGA研究了其热化学性能;利用紫外光谱、荧光光谱研究了其光化学性能;还利用循环伏安对其电化学性能进行了研究,探寻了其在光和电转化方面的应用潜力。通过测定三种目标化合物的热化学性能及荧光量子效率,表明咔唑基团能提高目标化合物的热稳定性,同时咔唑基团可提高目标化合物的液态荧光量子效率。其中目标化合物在DMF、THF、DMSO等溶液中的溶液荧光量子效率更是高达70%以上。通过积分球测试目标化合物的绝对荧光量子产率发现,目标化合物的固态荧光量子效率随着碳原子数目的增加而增加,液态荧光量子产率随着碳原子数的增加而减少,且液态荧光量子效率明显比固态荧光量子效率大。通过荧光寿命的测试可知含有两个碳烷基链接的目标化合物在THF中的平均寿命8.24纳秒,含有四个碳烷基链接的目标化合物在THF溶液中的平均寿命为8.02纳秒,含有两个碳烷基链接目标化合物固态平均寿命为1.04纳秒,含有四个碳烷基链接的目标化合物固态平均寿命为1.17纳秒。荧光寿命均在纳秒数量级,这正是典型的π-π*跃迁的寿命,通过测试发现化合物的荧光寿命正好与单线态激子的寿命相当,表明了该化合物发光主要为单线态激子发光。从电化学分析可知目标化合物的HOMO能级为-5.31 eV~-5.33eV,目标化合物的LUMO能级为-1.84 eV~-1.83 eV。对目标化合物的热稳定性研究可知,目标化合物的热分解温度分别为425℃,415℃,356℃,可知目标化合物具有热稳定性。从电化学和理论计算可知该目标化合物存在分子内电荷转移性能。
[Abstract]:Carbazole has a stable planar conjugate rigid structure in which nitrogen atoms have solitary pairs of electrons which are a dense ring structure and carbazole groups have excellent photoelectric properties. It not only has good photothermal stability, but also can carry out multiple chemical reactions. The design of carbazole in optoelectronic functional materials can not only guarantee its good optoelectronic properties, but also extend the design ideas of compounds. At present, carbazole groups are introduced into the main chain by conjugation, or carbazole is introduced into the polymer chain in different ways to form polymeric materials. Less research has been done on carbazole in the form of alkyl chains in the target compounds. Because the carbazole group connected with alkyl chain has the characteristics of electron giving, and carbazole itself has photoelectric property and charge transport property, this kind of material has great application potential in the field of optoelectronic materials. Solubility is a very important condition in organic luminescent materials. The introduction of alkyl chain in compounds can effectively improve the solubility and promote the deposition of high quality thin films. The stability and lifetime of optoelectronic devices depend on the thermal stability of compounds. Carbazole derivatives are a class of compounds with strong blue light emission, high TG temperature and thermal stability, which make them attractive candidates for OLED design. In this paper, three carbazole derivatives with different length alkyl chains are designed and synthesized with strong blue luminescence and high stability. Its thermochemical properties were studied by DSC-TGA, its photochemical properties were studied by UV spectra and fluorescence spectra, and its electrochemical properties were studied by cyclic voltammetry to explore its application potential in photo-electric conversion. By measuring the thermochemical properties and fluorescence quantum efficiency of the three target compounds, it is shown that the carbazole group can improve the thermal stability of the target compound and the carbazole group can improve the liquid fluorescence quantum efficiency of the target compound. The fluorescence quantum efficiency of the target compounds in DMFU THF DMSO solution is more than 70%. By measuring the absolute fluorescence quantum yield of the target compound with the integration sphere, it is found that the quantum efficiency of solid state fluorescence increases with the increase of the number of carbon atoms, and the quantum yield of liquid fluorescence decreases with the increase of the number of carbon atoms. The quantum efficiency of liquid fluorescence is higher than that of solid state fluorescence. The average lifetime of target compounds with two alkyl links in THF was 8.24 nanoseconds, and that of target compounds with four alkyl links in THF solution was 8.02 nanoseconds. The average solid-state life of target compounds containing two alkyl chains is 1.04 nanoseconds, and that of target compounds with four alkyl links is 1.17 nanoseconds. The fluorescence lifetime is in the order of nanosecond, which is exactly the lifetime of the typical 蟺-蟺 * transition. It is found that the fluorescence lifetime of the compound is exactly the same as that of the singlet exciton, which indicates that the luminescence of the compound is mainly a singlet exciton. Electrochemical analysis shows that the HOMO energy level of the target compound is -5.31 EV ~ (-5.33) EV, and the LUMO energy level of the target compound is -1.84 eV~-1.83 EV. The thermal stability of the target compound is studied. The thermal decomposition temperature of the target compound is 425 鈩，

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