具有光活性的电子给体_受体双缆型共轭聚合物的设计、合成和性能研究.pdf

中国科学技术大学博士学位论文具有光活性的电子给体/受体双缆型共轭聚合物的设计、合成和性能研究姓名：李明华申请学位级别：博士专业：材料学指导教师：杨上峰2011-05-02摘 要 I 摘 要 聚合物太阳能电池 (polymer solar Cells,PSCs)采用共轭导电聚合物作为光活性材料，加工简单，成本低廉，同时具有可制造柔性和大面积光伏器件的优点，近年来一直成为国际研究热点聚 合物太阳能电池中作为电子给体 (donor)的共轭聚合物和作为电子受体 (acceptor)的富勒烯材料的性质是 影响电池性能的重要因素，而给体和受体材料的能带匹配、相容性 及相分离尺寸的控制则是设计聚合物太阳能电池的光活性材料所需考虑的核心 问题本论文从合成新型的富勒烯/共轭聚合物分子异质结复合结构的的研究思路出发， 开展了以下几个方面的工作： (1) 合成了一种由 C60和戊基双取代的带支链的给体 /受体型 (donor/acceptor，D/A)聚乙炔衍生物（ PA-C60）并对其电子性质、光学性质和薄膜表面形貌进行了系统的研究结果表明 PA-C60在常用溶剂中有较好的溶解性我们首次发现 C60的取代使得双取代的乙炔单体的 聚合过程显著加快，并且在很短的时间内就可反应完毕（不超过 1.5 min），并对于此现象提出了相应的解释。

(2) 通过简单的三步后聚合反应，合成了一种可控含量 C60取代的电子给体 -π-受体 (donor-π-acceptor)双缆型聚己基噻吩（P3HT）衍生物 C60-Ph-P3HT，该结构中富勒烯和噻吩的连接是通过苯环结构作为桥梁实现的我们对C60-Ph-P3HT 的分子结构、电子性质、分子排列和薄膜表面形貌进行了一系列的表征，荧光光谱表征结果表明 C60的取代对于 P3HT 的荧光强度的淬灭可达到 98%， AFM 研究表明 C60-Ph-P3HT 薄膜的表面粗糙度均大于未取代的 P3HT综合此两方面的性质，我们提出 C60-Ph-P3HT 可以作为一种新型的光活性材料应用于聚合物太阳能电池中 (3) 利用后聚合反应合成了一种新型的芘（ pyrene）修饰的聚己基噻吩（ P3HT）衍生物 Pyrene-P3HT，并利用 Pyrene-P3HT 对单壁碳纳米管 (SWNTs)进行了不同比例的非共价修饰制备出 SWNT/Pyrene-P3HT 复合结构，深入研究了复合结构中 SWNT 和 Pyrene-P3HT 之间的非共价相互作用紫外 -可见吸收光谱、拉曼光谱和电子顺磁共振光谱电化学研究揭示了 Pyrene-P3HT 中的P3HT 通过芘单元与 SWNTs 发生电子相互作用。

荧光光谱表征表明 SWNTs的复合导致 Pyrene-P3HT 的荧光强度发生了将近 100%的淬灭， 证实了 P3HT与 SWNTs 之间可以通过芘单元发生光诱导电子转移对SWNT/Pyrene-P3HT 的薄膜表面形貌进行 SEM 和 TEM 研究的结果表明Pyrene-P3HT 可以很好地促进 SWNTs 在有机溶剂 THF 中的分散 摘 要 I 关键词 ：聚合物太阳能电池 (PSCs)，共轭聚合物，聚乙炔，富勒烯，聚己基噻吩 (P3HT)，单壁碳纳米管 (SWNTs), 芘(pyrene)，光谱表征 Abstract II ABSTRACT Polymer solar cells (PSCs) have been attracting much attention in recent years because of using conjugated conducting polymers as photoactive materials and the facility of large-area, flexible and low-cost fabrications. One of the important factors determining the performance of PSCs is the properties of the donor (conjugated conducting polymers) and acceptor (fullerene derivatives) materials, while the key issue for the design of the photoactive materials of PSCs is the compatibility and energetic matching of the donor/acceptor materials as well as the manipulation of their phase separation. In this dissertation, motivated by the synthesis of novel fullerene/conjugated polymer intermolecular heterojunction complexes, we have carried out the following works: (1) A novel type of donor/acceptor branched disubstituted polyacetylenes PAs (PA-C60) bearing C60and pentyl moieties in side chains were synthesized successfully, for which the electronic and optical properties and surface morphology of the thin film were studied. Our results indicated that PA-C60 was qutie soluble in common solvents. For the first time we found that the polymerization of the disubstituted monomer was significantly accelerated by C60pendant and could be finished within very short reaction time (up to 1.5 min). We proposed a plausible interpretation for this phenomena. (2) A novel type of soluble donor-π-acceptor double cable P3HT bearing C60pendant with tunable donor/acceptor ratio was synthesized via a facile three-step postpolymerization functionalization of P3HT. A phenyl group was integrated as the linking bridge of P3HT donor and C60 acceptor.The molecular structure, electronic property and thin film surface morphology of the synthesized C60-Ph-P3HT were characterized. Compared to the pristine P3HT, the fluorescence intensity of C60-Ph-P3HT was found to be dramatically quenched (up to 98%). The AFM measurements on the surface film morphology of C60-Ph-P3HT reveal the increased rms roughness compared to that of P3HT. Accordingly, we proposed that C60-Ph-P3HT may become a promising photoactive material in PSCs. (3) A novel pyrene-functionalized poly(3-hexylthiophene) (P3HT) derivative (Pyrene-P3HT) has been successfully synthesized via postpolymerization Abstract II approach, and was applied for the noncovalent functionalization of single-walled carbon tubes (SWNTs) affording the SWNT/Pyrene-P3HT composite, for which the noncovalent interactions between SWNTs and Pyrene-P3HT were studied in detail. The UV-vis, Raman spectroscopies and ESR spectroelectrochemical study have revealed the electronic interaction between P3HT and SWNTs through the pyrene unit. The fluorescence spectroscopy of SWNT/Pyrene-P3HT indicated a nearly 100% quenching of the fluorescence intensity compared to the reference Pyrene-P3HT, suggesting the a strong photo-induced electron transfer resulting from the noncovalent linkage of SWNTs to the P3HT backbone via the pyrene bridge. SEM and TEM studies on the film morphology of SWNT/Pyrene-P3HT shows that SWNTs are well dispersed in THF by Pyrene-P3HT. Key Words: polymer solar cells (PSCs), conjugated polymers, polyacetylenes (PAs), fullerenes, poly(3-hexyl)thiophene(P3HT), single-walled carbon nanotubes (SWNTs)， pyrene， spectroscopic characterization 中国科学技术大学学位论文原创性声明 本人声明所呈交的学位论文,是本人在导师指导下进行研究工作所取得的成果。

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