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Luminescent Materials with Aggregation -Induced Emission Characteristics: Molecular Design for Tuning Viscosity Sensitivity and Singlet-Triplet Energy Gap.

机译：具有聚集诱导发射特性的发光材料：用于调节粘度敏感性和单重态-三重态能隙的分子设计。

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Luminescent materials with aggregation-induced emission (AIE) characteristics have been of great interest in organic light-emitting diodes, organic light-emitting field-effect transistors, organic solid-sate lasers, solid-state lighting, two photon-absorption materials, mechanochromic materials, fluorescent probes for chemicals and bio-molecules as well as cell imaging. Therefore, development of new molecular design strategies and new AIE materials towards desired properties are of great importance.;In this thesis, research work is focused on two major areas of AIE materials, including modulation of singlet-triplet energy gap (DeltaE ST) of AIE materials and exploration of the phosphorescence and electroluminescent device performances thereof (Chapter II to IV), development of highly viscosity sensitive AIE molecules based on the restriction of intramlecular rotation (RIR) mechanism (Chapter V and VI). Efforts are devoted to the investigation on the relationship between the molecular structure and the properties of AIE materials, new molecular design strategies have been proposed and verified by comparative study.;In Chapter II, a series of triphenylethene (3TPE)-based AIE chromophores substituted with triphenylamine and phenylnitrile as done and acceptor groups at different positions towards modulation of DeltaE ST, respectively, were designed and synthesized in good yields. Some molecules with larger DeltaEST, the well separated HOMO and LUMO orbitals and severe steric hindrance, emitted efficient long-lived phosphorescence with lifetime up to several seconds in their glassy solutions at 77 K. Moreover, room temperature phosphorescence can be obtained from their crystals. The chromophores with highly twisted conformation exhibited improved mechanochromic behaviors with higher contrast. Electroluminescence devices using these molecules as emitting layers were fabricated, which exhibited external quantum efficiency equal or even exceed the theoretical values of singlet emitter-type devices. Particularly, the molecule with a small Delta EST value showed outstanding device performance with high luminance and efficiencies up to 36900 cd/m2, 11.2 lm/W, 12.8 cd/A and 4.37%, respectively, considering that the solid-state quantum yield is only 42%.;In Chapter III, another two triphenylethene-cored AIE dyes substituted with triphenylamine and dimesitylboron as the strong donor and acceptor were designed and prepared. These two molecules exhibited very similar photophysical properties, including UV-vis absorption, photoluminescence, aggregation-enhanced emission and twisted intramolecular charge transfer characteristics, as well as electrochemical properties. Similarly, o-TPA-3TPE- p-DMB, which exhibits a larger DeltaEST value, stronger steric hindrance and well separated HOMO/LUMO, showed much longer low temperature phosphorescence lifetime. Their electroluminescence were also investigated, and they exhibited efficient devices performances, with the luminance and efficiencies up to 6530/8460 cd/m2, 5.6/4.8 lm/W, 6.3/6.8 cd/A and 3.00/2.81%, respectively.;In Chapter IV, a new tetrapenylethene (TPE)-based AIE luminogen DPATPEPy substituted with triphenylamino and pyridine salt as very strong donor and acceptor, respectively, has been designed and synthesized. With the synergy between the strong electron donating and withdrawing effect and conformational twist of the TPE linkage, well spatially separated HOMO-LUMO orbitals was achieved, offering DPATPEPy with extremely small DeltaE ST (0.07 eV). Such low DeltaEST value promoted efficient delayed fluorescence in poly (methylmethacrylate) matrix doped with diluted dye molecules. However, the delayed fluorescence becomes much weaker in higher doping concentration and it cannot be detected in its thin film. Meanwhile the fluorescence of the thin film of the dye can be enhanced upon heating verifying its thermally activated nature.;In Chapter V, a novel molecular design strategy to enhance the viscosity sensitivity of AIE dye was proposed and verified. With an increase in the number of rotors, which can populate the non-radiative decay channels, enhance the quantum efficiency and enlarge the molecular size, the viscosity sensitivity of the newly designed AIE dyes was enhanced. Noteworthily, a high viscosity factor of 0.98 was achieved, which is the highest value reported so far.;In Chapter VI, with the synergy between AIE mechanism and ratiometry design principle, two new fluorescence ratiometric viscosity probes TPEAn-1 and TPEAn-2 with different conformational crowdedness were designed and synthesized. Their ratiometric measurement of viscosity was demonstrated with high sensitivity and improved reliability owing to its self-calibrating ability. And it was found that conformationally less crowded molecule exhibited much higher viscosity sensitivity. Moreover, the newly designed viscosity sensor was found to be two-photon absorption active, and the viscosity sensing process can be conducted via two-photon excited fluorescence (TPEF).;In the last chapter, a new kind of polymers with aggregation-enhanced emission characteristics has been synthesized via a new kind of alkyne polymerization. Interestingly,
机译：具有聚集诱导发射（AIE）特性的发光材料在有机发光二极管，有机发光场效应晶体管，有机固态激光器，固态照明，两种光子吸收材料，机械变色中引起了人们的极大兴趣。材料，化学和生物分子荧光探针以及细胞成像。因此，开发新的分子设计策略和新的AIE材料以达到理想的性能具有重要意义。本论文的研究工作集中在AIE材料的两个主要领域，包括单线三重态能隙（DeltaE ST）的调节。 AIE材料及其磷光和电致发光器件性能的探索（第二章至第四章），基于分子内旋转（RIR）机理的限制（第五章和第六章），开发了对高粘度敏感的AIE分子。致力于AIE材料的分子结构与性能之间关系的研究，提出了新的分子设计策略，并进行了对比研究验证。第二章，一系列基于三苯乙稀（3TPE）的AIE发色团的取代分别设计了三苯胺和苯腈，分别在不同位置调节DeltaE ST的受体基团，并以高收率合成。一些具有较大DeltaEST的分子，HOMO和LUMO轨道分隔得很好并且空间位阻严重，它们在77 K的玻璃状溶液中发出有效的长寿命磷光，寿命长达数秒。此外，可以从其晶体获得室温磷光。具有高度扭曲构象的生色团表现出改善的机械变色行为，具有更高的对比度。制备了使用这些分子作为发射层的电致发光器件，其外部量子效率等于或什至超过单线态发射体型器件的理论值。特别是，考虑到固态量子产率为，具有EST值小的分子表现出出色的器件性能，具有高亮度和高达36900 cd / m2、11.2 lm / W，12.8 cd / A和4.37％的效率。在第三章中，还设计和制备了另外两种被三苯胺和二甲磺隆替代的三苯乙烯芯AIE染料。这两个分子表现出非常相似的光物理性质，包括紫外可见吸收，光致发光，聚集增强的发射和扭曲的分子内电荷转移特性以及电化学性质。类似地，o-TPA-3TPE-p-DMB表现出更大的DeltaEST值，更强的空间位阻和良好的HOMO / LUMO分离度，它们的低温磷光寿命更长。还研究了它们的电致发光，并显示出有效的器件性能，其亮度和效率分别高达6530/8460 cd / m2、5.6 / 4.8 lm / W，6.3 / 6.8 cd / A和3.00 / 2.81％。第四章，设计并合成了一种新的基于四烯基乙烯（TPE）的AIE发光剂DPATPEPy，该化合物被三苯基氨基和吡啶盐分别取代为非常强的供体和受体。通过强力的电子给与吸作用和TPE键构象扭曲之间的协同作用，实现了空间上分隔良好的HOMO-LUMO轨道，从而为DPATPEPy提供了极小的DeltaE ST（0.07 eV）。如此低的DeltaEST值促进了掺有稀释染料分子的聚（甲基丙烯酸甲酯）基质中的有效延迟荧光。然而，在较高的掺杂浓度下，延迟的荧光变得非常弱，并且在其薄膜中无法检测到。同时通过验证其热活化性质，可以提高染料薄膜的荧光性。第五章提出并验证了提高AIE染料粘度敏感性的新分子设计策略。随着转子数量的增加，可以填充非辐射衰变通道，提高量子效率并扩大分子大小，新设计的AIE染料的粘度敏感性得到了提高。值得注意的是，实现了0.98的高粘度因子，这是迄今为止报道的最高值。在第六章中，利用AIE机理与比率设计原理的协同作用，两个新的荧光比率粘度探针TPEAn-1和TPEAn-2设计并合成了不同的构象拥挤。由于它们的自校准能力，因此证明了它们的粘度比测量具有高灵敏度和更高的可靠性。并且发现构象较少的拥挤分子表现出高得多的粘度敏感性。此外，发现新设计的粘度传感器具有两光子吸收活性在上一章中，通过一种新型的炔烃聚合反应合成了一种具有团聚增强发射特性的新型聚合物。有趣的是

著录项

  • 作者

    Li, Jie.;

  • 作者单位

    Hong Kong University of Science and Technology (Hong Kong).;

  • 授予单位 Hong Kong University of Science and Technology (Hong Kong).;
  • 学科 Analytical chemistry.;Physical chemistry.
  • 学位 Ph.D.
  • 年度 2013
  • 页码 244 p.
  • 总页数 244
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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