三嗪和吡嗪类热致延迟荧光材料的合成及性能研究

发布时间：2018-06-07 05:02

本文选题：有机发光二极管 + 热致延迟荧光　；参考：《大连理工大学》2015年硕士论文

【摘要】：有机发光二极管(OLEDs, Organic light-emitting diodes)作为近几年发展迅速并有巨大应用前景的新型平板显示技术,是有机光电子领域的热门研究方向。与传统的荧光材料和磷光材料相比,热致延迟荧光材料兼具二者的优点,它既能够充分利用单重态激子发光又能充分利用三重态激子发光而使得器件内量子效率理论上达到100%。热致延迟荧光材料为有机小分子,化学性质稳定且不需要和贵重金属配位使得器件成本大幅降低。因而,研究、开发新型的热致延迟荧光材料具有十分重要的现实意义。热致延迟荧光材料一般要求化合物具有给电子性很强的P型基团和吸电子性能很强的N型基团,三嗪是一类性能非常好的电子传输功能基团,吡嗪及其衍生物由于具有较高的荧光量子产率,优异的光热稳定性和化学稳定性,广泛应用于有机光电子领域。通过氰基修饰的吡嗪衍生物,与吡嗪相比具有更强的吸电子性能,并且它们在热致延迟荧光领域的应用还未见报道。咔唑是一类具有很强供电子性的空穴传输功能基团,并有较大的空间立体构型,以它为电子给体构建的化合物通常具有较高的空穴迁移率和较好的热稳定性。本文以三嗪和二氰基吡嗪为N型基团、氮苯基咔唑为P型基团,适当调控分子的立体构型,构造出了两大类八种目前均未见报道的新型延迟荧光分子。使用紫外-可见吸收光谱仪、荧光分光光度计、循环伏安法、瞬态吸收光谱仪等测试研究了这些化合物的光物理性质和电化学性质。通过理论计算了化合物的HOMO和LUMO能级分布,计算结果显示所有化合物的HOMO与LUMO几乎完全分离。通过测试其中二氰基吡嗪类化合物M5的纳秒瞬态吸收光谱研究了它的瞬态光物理性质,研究发现M5在室温条件下具有长寿命的三重态(32.2¨s),荧光寿命测试结果证实M5在波长500 nm处的荧光不仅包括短寿命(纳秒级)的瞬时荧光(PF),而且还包括长寿命(微秒级)的延迟荧光(DF),且延迟荧光寿命在除氧甲苯中达52¨s,如此长的延迟荧光寿命比传统荧光寿命高出1000倍以上。以其中三嗪类化合物M1为双偶极主体材料,Firpic和Ir(ppy)3分别为发光客体制备了相应的蓝色和绿色磷光器件,研究了它的电致发光性质。蓝色和绿色磷光器件均具有高效的器件性能。其中,绿色磷光器件的最大效率分别为96.9 cd/A和28.7%。结果表明,M1既可以作为发光材料应用于有机电致发光器件中,又表现出较好的主体材料性能。
[Abstract]:As a new flat panel display technology with rapid development and great prospect in recent years, organic light-emitting diode (OLEDs) is a hot research direction in the field of organic optoelectronics. Compared with the traditional fluorescent material and phosphorescent material, the thermally induced delayed fluorescence material has the advantages of both. It can make full use of the singlet exciton luminescence and triplet exciton luminescence, so that the quantum efficiency of the device can reach 100% theoretically. The thermally induced delayed fluorescence materials are organic small molecules, which have stable chemical properties and do not need to coordinate with precious metals, so the device cost is greatly reduced. Therefore, it is of great practical significance to study and develop new thermal delayed fluorescence materials. Thermally induced delayed fluorescence materials generally require the compounds to have strong electronic-dependent P-type groups and strong electron-absorbing N-type groups. Triazine is a class of electron transport functional groups with very good properties. Pyrazine and its derivatives have been widely used in the field of organic optoelectronics due to their high fluorescence quantum yield excellent photothermal and chemical stability. The cyanide-modified pyrazine derivatives have stronger electron absorption properties than pyrazines, and their applications in the field of thermo-induced delayed fluorescence have not been reported. Carbazole is a kind of hole transport group with strong electron supply and has a large spatial stereoscopic configuration. The compounds constructed with carbazole as electron donor usually have higher hole mobility and better thermal stability. In this paper, using triazine and dicyanopyrazine as N-type group, nitrophenyl carbazole as P-type group, and regulating the stereomorphism of the molecule properly, two kinds of eight kinds of novel delayed fluorescent molecules have been constructed, which have not been reported at present. The photophysical and electrochemical properties of these compounds were investigated by UV-Vis absorption spectrometer, fluorescence spectrophotometer, cyclic voltammetry and transient absorption spectrometer. The distributions of HOMO and LUMO energy levels of the compounds are calculated theoretically. The results show that the HOMO and LUMO of all the compounds are almost completely separated. The transient photophysical properties of dicyanopyrazines M5 were studied by nanosecond transient absorption spectra. It is found that M5 has a long lifetime triplet at room temperature. The fluorescence lifetime test shows that the fluorescence of M5 at wavelength 500nm includes not only short-lived (nanosecond) transient fluorescence, but also long-lifetime (microsecond) fluorescence. The delayed fluorescence lifetime is 52? s in deoxygenated toluene, which is more than 1000 times higher than that of the traditional fluorescence lifetime. The blue and green phosphorescence devices were prepared by using triazine M _ 1 as the bipolar host materials and Ir(ppy)3 as the luminescent object respectively. The electroluminescent properties of the devices were investigated. Both blue and green phosphors have high performance. The maximum efficiency of green phosphor is 96. 9 cd/A and 28. 7 respectively. The results show that MNO _ (1) can be used as a luminescent material in organic electroluminescent devices, and it also shows a good performance of the main material.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN383.1

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