【作者】 王华；

【导师】 冯圣玉；

【作者基本信息】 山东大学 ， 高分子化学与物理， 2014， 博士

【摘要】 本文首先设计制备了二苯基荧蒽和三种以硅为核的四面体荧蒽官能化硅烷,并对其进行了全面系统的性质结构研究。结果表明,在引入以硅为核的四面体结构后,与二苯基荧蒽相比,荧蒽官能化硅烷表现出更高的热稳定性以及更高的玻璃化转变温度,这些优异的热性质使得该官能化硅烷在应用于器件时将具有更好的稳定性和更长的器件寿命。通过对二苯基荧蒽和三种官能化硅烷在稀溶液中的紫外吸收光谱、荧光发射光谱和循环伏安曲线进行测试后,发现以硅为核的四面体结构的引入并不会明显改变荧蒽基团的共轭度,较好的保持了荧蒽自身的性质。不同的是,所有的荧蒽官能化硅烷相比二苯基荧蒽来说,都表现出更弱的聚集态荧光红移现象,这可归结于以硅为核四面体结构的引入可有效减弱聚集态中π-π相互作用以及分子间相互作用。此外,硅原子上其它的取代基对于整个分子的结构以及聚集态荧光性质也有着重要的影响,与二甲基和二苯基官能化硅烷相比,一甲基一苯基官能化硅烷表现出更加优异的聚集态荧光性能,并且在固态的荧光光谱与在稀溶液中荧光光谱相比几乎没有变化,是一种特别适合应用于光电器件的发光材料。该研究工作将对应用于光电领域的以硅为核的化合物的设计和合成提供指导作用。基于以上所合成的一系列荧蒽官能化硅烷均具有强烈的蓝光发射,在完成对其自身荧光性质的研究后,进一步展开了其在共混体系中荧光行为的研究。选用合成的具有优异固态发光性质的蓝光发射单元官能化硅烷双(7,10-二苯基-荧蒽基)甲基苯基硅烷(BFMPS),作为共混体系中的给体单元。此外选择具有较好柔顺性的聚硅氧烷链对苝酰亚胺进行修饰,合成了苝酰亚胺封端的聚硅氧烷(简称PECP)。该硅氧烷表现出强烈的橙光发射,以及优异的溶解性和成膜能力。PECP的紫外吸收光谱与BFMPS的荧光发射光谱在450-500nm波长范围内具有较好的重叠,从而提供两者发生能量转移的可能性。研究了不同共混比例的PECP/BFMPS共混体系在二氯甲烷稀溶液中的荧光性质,制备了一系列不同共混比例PECP/BFMPS体系的固态薄膜。该共混体系在稀溶液和固态薄膜中都表现出基于能量转移的可调多色荧光发射,并且在比例合适时均可以发射白光。此外,进一步研究了该共混体系在稀溶液和薄膜中的光物理性质,发现在稀溶液和薄膜中,该共混体系存在两种不同的能量传递机制：在稀溶液中,该共混体系能量转移机理为辐射能量转移机制,而在固态薄膜中为Foster能量转移机制。基于上述关于荧蒽官能化硅烷与花酰亚胺能量转移的研究,进一步将其应用于制备新型功能材料。合成了以环己基修饰的花酰亚胺(CH-PTCDI)作为掺杂剂分子,并选用双(7,10-二苯基-荧蒽基)甲基苯基硅烷(BFMPS)作为分散剂分子,通过再沉淀法制备了一系列CH-PTCDI含量不同的BFMPS/CH-PTCDI有机复合纳米颗粒,这是第一次将官能化硅烷引入有机复合纳米发光颗粒的制备中。在该纳米颗粒中,观测到了从BFMPS向CH-PTCDI的高效能量转移,而且所得到的一系列有机复合纳米颗粒均表现出强荧光发射以及荧光可调控性能,在该复合纳米颗粒中,微小的CH-PTCDI含量变化就能明显地改变复合纳米颗粒的荧光性能。通过调节CH-PTCDI含量,我们实现了该有机复合纳米颗粒从蓝光到红光的调控。当CH-PTCDI含量适当时,得到了具有重要应用价值的白光复合纳米颗粒。聚集诱导发光研究是目前发光材料研究中的热点,它有可能从根本上解决荧光分子在聚集态荧光减弱和猝灭的问题。设计开发了合成简便、结构简单的新型聚集诱导发光体系,即树枝状多苯基体系。合成了四苯基苯和五苯基苯,对其自身的光学性质进行了研究,发现其在低浓度时具有聚集诱导发光增强性质(AIEE),而在高浓度时,展现出独特的与其它AIE分子不同的特性,这归结于其独特的分子结构及堆积方式。此外,进一步设计合成了以硅为核的四苯基苯化合物,研究发现,该化合物同样呈现出与上述两种分子相似的聚集诱导发光性质,且以硅为核结构的引入有效地增强了四苯基苯分子的荧光强度和调节其发光行为,我们将这种增强和调节现象称之为“硅核效应”。更多还原

【Abstract】 In this paper, diphenylfluoranthene and three novel silicon-cored diphenylfluoranthene derivatives were synthesized by convenient ways. The systematic properties and structures of four compounds were investigated and discussed. In contrast to diphenylfluoranthene, these silicone-cored diphenylfluoranthene derivatives show higher thermal stabilities and glass transition temperatures. These silicon-cored compounds with excellent thermal properties will be suitable to apply in organic opticelectric devices. The absorption spectra, fluorescence emission spectra and cyclic voltammetry (CV) spectra of four compounds in dilute solution were tested and it was found that they exhibited similar spectra in dilute solution, indicating that the silicon-cored structures did not change the conjugation length of diphenylfluoranthene and well retained the nature properties of diphenylfluoranthene. However, the silicon-cored derivatives exhibited better fluorescent emission properties in solid state than diphenylfluoranthene because these silicone-cored derivates exhibited weaker π-π interactions among molecules. Furthermore, it was found that the substituent groups on Si atom have great influence on the fluorescent emission properties in solid state. The silicon-cored methylphenyl diphenylfluoranthene derivative exhibited better fluorescence emission than dimethyl and diphenyl silicon-cored derivatives. And it showed similar fluorescence emission spectra in both solution and solid state which may be the most appreciate candidate for efficient solid-state emitter.A silicon-cored fluoranthene derivative named bis (7,10-diphenyl-fluoranthene) methylphenylsilane (BFMPS) was designed and synthesized as the donor. A perylene end-capped polydimethylsiloxane (PECP) with high orange emission, good solubility and film forming ability was synthesized and used as the acceptor for preparing the blending systems. A series of tunable luminescence was obtained by controlling the donor/acceptor ratios. The absorption spectrum of PECP showed a good overlap with the luminescent emission spectrum of BFMPS from400nm to550nm. This overlapping indicated the possibility of energy transfer from BFMPS to PECP. Efficient energy transfer was detected in these unique blending systems, which were composed of small molecules and fluorescence macromolecules. Based on the energy transfer, the BFMPS/PECP blending system showed tunable fluorescence emission colors in both solution and thin films. In particular, pure white emission was obtained when the adequate blending ratio was adopted. Further characterizations and investigations were carried out to examine the energy transfer from donor to acceptor in both solution and solid thin films. Two different energy transfer mechanisms were deduced from the investigation of the ultraviolet absorption and luminescence spectra. Radiative energy transfer was dominant in solution while Foster resonant energy transfer was dominant in thin films.Based on the energy transfer mechanism between BFMPS and perylene tetracarboxylic acid bisimide, functional materials were prepared. N,N-dicyclohexyl-perylene-3,4,9,10-tetracarboxylic acid bisimide (CH-PTCDI), a PTCDI derived from simple modification, was selected as the acceptor for preparing energy transfer system. a series of organic composte BFMPS/CH-PTCDI nanoparticles with different CH-PTCDI content by reprecipitation were obtained. To our knowledge, it was the first report that the silicon-containing molecules were used in orgainc composite nanoparticles. The composite nanoparticles exhibited good stability and thermal properties. The fluorescence emission of the perylene bisimide dye can be efficiently enhanced in composite nanoparticles based on efficient Foster resonant energy transfer. The composite nanoparticles exhibited tunable emission colors from blue to red by changing the concentration of perylene bisimide dye. White-light emission with CIE coordinates (0.327,0.339) was obtained as a good candidate for applications in white optoelectronic devices.The materials with aggregation induced emission (AIE) were important in luminescenct materials because they could fundamentally solve the aggregation caused quenching of chromophore. In this paper, a novel AIE system based on dendritic bezene was reported. Tetraphenyl benzene and its two derivates were synthesized and their optical behaviors were partically investigated. All the three compounds exhibited aggregation induced emission enhancement (AIEE) properties at a low concentration. The AIEE mechnism was investigated and indue to restricted intramolecular rotation and unique molecular packing modes. However, this kind of dendritic benzene derivatives exhibited interesting optical properties with increased concentration which is different from common AIE molecules. Furthermore, a new phenonmenon that the silicon-cored structure could efficiently enhance emission intensity and adjust emission colors of dendritic benzene was found. The phenomenon was called "silicon-cored effect." This effect may give some guidance to the design of new luminescent materials with AIE properties.更多还原