【作者】 于江；

【导师】 徐伟箭；

【作者基本信息】 湖南大学 ， 应用化学， 2006， 硕士

【摘要】 光电高分子材料越来越引起人们的关注,其基础研究、器件制作和应用研究在国际上十分活跃。其中,研究得最深入且在实用化方面已有突破或有望获得突破的主要集中在电致发光和光伏打材料上。通过广泛的文献阅读发现,目前在聚合物电致发光材料和聚合物光伏打材料方面的研究主要集中在π-共轭聚合物上,较少有人关注σ-共轭聚合物。聚硅烷是一类新型σ共轭聚合物,主链全部为硅原子,由于σ电子沿整个硅链广泛离域而显示出特殊优异的光电性能,如强紫外吸收和荧光光谱,光导性好,同时很强的空穴流动性和传输能力,以及非线性光学性等。有很好的应用前景,引起了材料学家的极大兴趣。目前,在聚合物电致发光材料和聚合物光伏打材料方面的应用涉及到的主要是线型聚硅烷。与此同时,研究发现,超支化聚硅烷具有比线型聚硅烷更优异的光电性能:随着支化结构的增加,吸收光谱有红移,荧光光谱发生红移,Stokes位移增大,通过控制支化度及侧链官能团有望控制其发光颜色且使其能隙(Eg)减小,支化结构更有利于形成复合物。这些对于其在聚合物电致发光和光伏打器件中的应用都极其有利。我们的工作就是基于上述考虑,研究超支化聚硅烷及其与富勒烯的复合物在光电材料方面的开发和应用。在线型聚硅烷研究的基础上,采用二官能度硅烷(甲基苯基二氯硅烷)和三官能度硅烷(甲基三氯硅烷)为单体,在金属钠作用下于惰性溶剂甲苯中进行武兹偶联合成超支化聚硅烷。期望通过支化结构获得一些不同于线型聚硅烷的特殊优异的性能,特别是光电性能。参考π-共轭聚合物和富勒烯复合的基础和理论,采用原位聚合法制备超支化σ-共轭聚合物和富勒烯的复合物,即在富勒烯存在的条件下合成超支化聚硅烷。利用两者的3-D结构期望制备出一种新型具有互穿结构的电子给体/受体复合物。我们通过各种方式对产物进行全面的表征,研究了其结构、性质及潜在的应用前景。结果表明,我们采用武兹缩合法成功合成出了超支化聚硅烷PMPS-co-MS,产物溶解性良好,分子量较高,支化度较高,光致蓝光,荧光量子产率约为0.17,热稳定性良好,玻璃化转变温度高,是一种很好的蓝光聚合物发光材料。采用原位聚合法成功合成出了超支化聚硅烷/富勒烯的复合物;产物分子量较高,溶解性好,支化度较高,荧光猝灭明显,说明超支化聚硅烷和富勒烯之间可能发生了光诱导电子转移,是一种具有良好性能的新型电子给体/受体复合物。研究还发现在超支化聚硅烷和富勒烯之间可能存在π-π堆积作用,这种电子给体和受体之间的π-π堆积作用可能会使复合物具有许多奇异的性质和潜在的应用前景。更多还原

【Abstract】 Recently, in the world, much attention has been paid on the fundamental research、devices preparing and application of optoelectric polymer materials. Among these, the researches are mainly focused on polymer light emitting materials and polymer photovoltaic materials.To date, the majority of works about the two areas reported in the previous literatures are mainly focused onπ-conjugated polymers, however, there are few works onσ-conjugated polymers. Polysilanes are a new class ofσ-conjugated polymers with the backbone consisting of tetrahedrally coordinated silicon atoms and different side-chain substituent groups. Due to the extensive delocalization ofσ-electrons along the silicon main chain,σ-conjugated polymers have many interesting electronic properties such as photoconductivity with high hole mobility, large nonlinear optical effects and effective UV light emission, which make them a promising application in optoelectric materials, and have drawn the interests of the material scientists. The common use of polysilanes as optoelectric materials has been mainly focused on one-dimensional linear polysilanes. Meanwhile, three-dimensional hyperbranched polysilanes different from linear polysilanes, have better optoelectric properties, such as, red shift of absorption and emission spectra, more large stokes shift, reduced bandgap due to the extent ofσ-conjugation at branching points. And its 3-D structure is very propitious to preparing electron donor/acceptor composite with interpenetrating structure with electron acceptor fullerene. All these make the hyperbranched polysilanes may be good candidates for polymer light emitting and polymer photovoltaic materials.In this work, we report on the synthesis and characterization of a novel hyperbranched polysilane and its composite with fullerene.Based on the previous reports of linear polysilanes, we synthesized a novel hyperbranched polysilane polymethylphenylsilane-co-methylsilane (PMPS-co-MS) via Wurtz-type reaction using dichloromethylphenylsilane and trichloromethylsilane as monomers, which is designed to obtain better optoelectric properties than linear polysilanes. Then, based on the synthesis and theory ofπ-conjugated polymers/fullerene composites, we prepared a novel hyperbranchedσ-conjugated polymer/fullerene using in-situ polymerization, that is synthesized the hyperbranched polysilane in the presence of fullerene. The novel electron donor/acceptor composite may have well defined interpenetrating structure because of 3-D structure of both hyperbranched polysilane and fullerene. We also characterized by means of methods and discussed the structures, properties, and potential applications of the products.After fully studied, we found that: The resulting hyperbranched polysilane synthesized via Wurtz-type reaction shows good solubility in common organic solvents, high molecular weight (Mw=12093), well defined hyperbranched structure, blue fluorescence with a quantum yield about 0.17, good thermal stability, and high glass transition temperature. All these indicate that it may be a good optoelectric material. The composite we prepared shows good solubility, high molecular weight, good thermal stability, well defined interpenetrating structure, effective photoinduced electron transfer indicated by the obvious photoluminescence (PL) quenching, which suggests that it may be a good electron donor/acceptor composite. Further discussion found that there may beπ-πstacking between hyperbranched polysilane and fullerene, which may make the composite have many interesting properties and promising applications.更多还原