双键及侧链效应对苯并噻二唑共轭聚合物光电性质影响研究

发布时间：2018-03-04 09:37

本文选题：苯并噻二唑　切入点：有机场效应晶体管　出处：《重庆大学》2015年硕士论文　论文类型：学位论文

【摘要】：聚合物半导体材料具有种类多,质量轻,可溶液加工和柔性好等优点,在构筑大面积柔性器件方面具有广泛的应用前景。除了共轭聚合物的电子给体和电子受体单元,单元之间的键连接方式和侧链的取代位置也对共轭聚合物的性质有很大的影响。本文设计、合成了一系列稳定性良好的D-A型共轭聚合物,通过吸收光谱、电化学、理论计算和制作场效应器件的方法,系统的研究并分析了双键作为链接单元对不同侧链取代位置的苯并噻二唑类聚合物的能级、分子结构和场效应性能影响。本论文包含以下两个方面:①设计、合成D-A型共轭聚合物DA1、DA2和DA3。研究结果表明,双键的引入能够有效的提高聚合物DA2、DA3分子骨架的共平面性,带隙明显降低,带隙的降低主要来源于分子的HOMO能级的提高。制备三种聚合物的底栅顶接触结构的场效应晶体管,都展现出典型的p型性能。噻吩单元之间以σ键为链接方式的DA1,分子骨架出现扭转,空穴迁移率仅为1.4×10-4 cm2/(Vs);将双键引入到噻吩单元之间,DA2由于平面性增强,空穴迁移率增加到2.1×10-3cm2/(Vs);DA3分子在苯并噻二唑与噻吩单元之间引入双键,迁移率最高达到0.024 cm2/(Vs)。通过XRD和AFM观察聚合物的结构与形貌,160oC退火处理后,三者的结晶性增强,但没有观察到一定规模结构规整的堆积形态。②为了研究侧链对共轭聚合物光电性质的影响,在上述研究的基础上,设计、合成了聚合物DA4、DA5和DA6。研究表明,侧链取代位置的变化导致DA4和DA5光谱与电化学性质变化。其中,DA5的变化最为明显,双键的引入、并没有增强DA5平面性,相反,DA5的溶液/薄膜的光谱吸收比DA4分别蓝移了5nm、35nm,带隙因此上升到2.00e V。三种材料的晶体管同样展现了典型的p型性能,DA4迁移率仅为1.2×10-6 cm2/(Vs);DA5迁移率下降至0.7×10-6 cm2/(Vs);DA6的迁移率为0.011 cm2/(Vs)。对比DA4与DA1,DA5与DA2,DA4、DA5的场效应性能有着显著的降低,而DA6与DA3保持在同一个数量级上。
[Abstract]:Polymer semiconductor materials have many advantages, such as variety, light weight, good solution processing and flexibility. They have a wide application prospect in building large area flexible devices, except electron donor and acceptor unit of conjugated polymer. The bonding mode between units and the substitution position of side chains also have great influence on the properties of conjugated polymers. In this paper, a series of stable D-A conjugated polymers have been designed and synthesized. The method of theoretical calculation and fabrication of field effect devices is presented. The energy levels of benzothiadiazole polymers with different side chain substitution positions are systematically studied and analyzed. The molecular structure and field effect properties are affected. In this thesis, the following two kinds of conjugated polymers, DA1, DA2 and DA3, are designed and synthesized. The results show that the introduction of double bonds can effectively improve the coplanarity of the polymer DA2NDA3 molecular framework. The decrease of band gap is mainly due to the increase of HOMO energy level of molecule. Three kinds of polymer field effect transistors with bottom gate top contact structure are prepared. Both show typical p-type properties. For DA1 with 蟽 bond between thiophene units, the molecular skeleton is torsional and the hole mobility is only 1.4 脳 10 ~ (-4) cm ~ (2) 路s ~ (-2) / V _ (s1). The introduction of double bond into thiophene unit is enhanced due to its planarity. The hole mobility was increased to 2.1 脳 10 ~ (-3) cm ~ (-2) / m ~ (-1) V _ (sn) D _ (3), and a double bond was introduced between benzothiadiazole and thiophene unit. The maximum mobility was 0.024 cm ~ (2) / m ~ (-1) V _ (s1). The crystallinity of the three molecules was enhanced after annealing with XRD and AFM to observe the structure and morphology of the polymer (160oC). In order to study the effect of side chains on the photoelectric properties of conjugated polymers, polymers DA4NDA5 and DA6were designed and synthesized on the basis of the above studies. The change of side chain substitution position resulted in the changes of DA4 and DA5 spectra and electrochemical properties, among which the change of DA5 DA5 was the most obvious, and the introduction of double bonds did not enhance the planarity of DA5. On the contrary, the spectral absorption ratio of the solution / thin film of DA5 shifted 5 nm to 35 nm respectively, and the band gap rose to 2.00e V. the typical p-type transistors also showed that the mobility of the typical p-type DBA _ 4 was only 1.2 脳 10 ~ (-6) cm ~ (-2) / m ~ (2) / V ~ (-1) ~ (-1) V ~ (-1), which decreased to 0.7 脳 10 ~ (-6) cm ~ (2 /) V ~ (-1) D _ 6. The rate is 0.011 cm ~ (2) / V ~ (s1). The field effect performance of DA4 and DA1 / DA5 and DA2 / DA4 / DA5 is significantly reduced. DA6 and DA3 remain in the same order of magnitude.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304

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