共轭聚合物及有机无机复合空穴传输材料的制备与光电性能的研究

发布时间：2018-05-14 01:25

本文选题：共轭聚合物 + 侧链　；参考：《东南大学》2017年硕士论文

【摘要】：共轭聚合物具有广泛的原料来源,良好的结构可调控性、可制成柔性器件等优点,广泛应用于太阳能电池和有机场效应晶体管等电子器件中。共轭聚合物的性质很大程度上决定了器件的性能,聚合物结构的优化主要有主链调控和侧链调控两种方法。本文主要侧重于侧链末端功能化方法。通过侧链末端功能化可以增加聚合物的分子聚集性,建立连续的电荷传输通道,有利于载流子迁移率的提高。此外,将聚合物和高导电性的碳材料复合,并对侧链进行修饰增强聚合物与碳材料之间的相溶性性,有望提高其导电性。本论文通过侧链调控共轭聚合物与高导电性的氧化石墨烯复合用于本体异质结的的空穴传输层有望提高光电转换效率和稳定性。我们主要展开了以下工作:1)鉴于共轭聚合物用于空穴传输材料的载流子迁移率较低,将共轭聚合物材料与氧化石墨烯复合有望提高其导电性。但有机聚合物和氧化石墨烯之间的相容性差,共混时易形成宏观相分离,界面接触不好,难以形成连续的互穿网络结构,不利于激子的分离和电荷的传输。为改善其复合界面性质,我们合成了侧链含芘的分别基于聚咔唑和聚苯并噻二吩-咔唑的聚合物PPOC和PPOCBDT。分别尝试用聚合物与GO混合涂膜和GO+聚合物+GO三层膜两种方式复合,发现混合涂膜的膜形貌较差,最后采用了三层膜的复合方式。聚合物通过芘以非共价键与氧化石墨烯复合,增加了其空穴传输性能,提高了本体异质结太阳能电池的光电转换效率。同时平面性更好的PPOCBDT与GO的复合更好,光电转换效率较高,此外,还研究了基于PPOCBDT和不同厚度的GO对光电转换效率的影响。2)基于咔唑-吡咯并吡咯基团为主链单元,制备得到了一系列聚合物PCDPP、PPOCDPP和PCCDPP。其中在聚合物PPOCDPP和PCCDPP烷基侧链分别修饰不同的稠环单元芘和咔唑基团。系统探索了侧链末端功能化对聚合物光吸收性能、电化学以及光电性能和热稳定性等方面的影响以及结构和性能的关系。研究结果表明聚合物PPOCDPP与PCCDPP的分子聚集性得到了增强,形成了短程有序聚集体,最终增加了聚合物的载流子迁移率。咔唑对聚合物的结晶度有抑制作用,而芘没有影响,所以含芘的载流子迁移率为最高。3)基于苯并噻二唑为受体单元,分别以咔唑以及烷基末端芘修饰的咔唑为给体单元合成了聚合物PCBT和PPOCBT。系统探索了侧链末端芘修饰对聚合物光吸收性能、性能、电化学以及光电性能的影响。发现对于以咔唑和苯并噻二唑为主链单元的聚合物材料,芘基团对其性能影响较小。这可能归因于聚合物主链分子内电荷转移较弱,聚集较为无序,使得芘基团难以起到桥联作用。且由于两种聚合物和富勒烯衍生物共混都可以获得较为均匀的共混膜,两种聚合物的光电转换效率相差不大。
[Abstract]:Conjugated polymers are widely used in solar cells, airfield effect transistors and other electronic devices because of their wide range of raw materials, good structural controllability, flexible devices and so on. The properties of conjugated polymers largely determine the performance of the devices. There are two methods to optimize the polymer structure: main chain control and side chain control. This paper mainly focuses on the method of side chain terminal functionalization. The side chain end functionalization can increase the molecular aggregation of the polymer, and establish a continuous charge transfer channel, which is beneficial to the increase of carrier mobility. In addition, it is expected to improve the conductivity of the polymer by combining the polymer with the high conductivity carbon material and modifying the side chain to enhance the compatibility between the polymer and the carbon material. In this paper, the side chain controlled conjugated polymer and high conductivity graphene oxide composite used in bulk heterojunction hole transport layer is expected to improve the photoelectric conversion efficiency and stability. In view of the low carrier mobility of conjugated polymers for hole transport materials, it is possible to improve the conductivity of conjugated polymers by combining them with graphene oxide. However, the compatibility between organic polymers and graphene oxide is poor, the macroscopic phase separation is easy to be formed during blending, the interface contact is not good, and it is difficult to form a continuous interpenetrating network structure, which is not conducive to the separation of excitons and the transport of charges. In order to improve the composite interfacial properties, we synthesized polycarbazole and polybenzothiophene-carbazole based polymers PPOC and PPOCBDTs with pyrene in side chain, respectively. It was found that the film morphology of the mixed coating was poor, and the composite mode of three layers was adopted. The polymer is composed of pyrene and graphene oxide by non-covalent bonding, which increases its hole transport performance and improves the photoelectric conversion efficiency of bulk heterojunction solar cells. In addition, the effect of PPOCBDT and go on photoconversion efficiency was studied based on carbazole-pyrrole group as main chain unit. A series of polymers, PCDPPP-PPOCDPP and PCCDPPPPP, were prepared. The polycyclic pyrene and carbazole groups were modified in the alkyl side chains of polymer PPOCDPP and PCCDPP, respectively. The effects of side chain terminal functionalization on the optical absorption, electrochemical, photoelectric and thermal stability of the polymer and the relationship between the structure and the properties of the polymer were systematically investigated. The results show that the molecular aggregation of polymer PPOCDPP and PCCDPP is enhanced, resulting in a short-range ordered aggregation, which increases the carrier mobility of the polymer. Carbazole inhibits the crystallinity of the polymer, but pyrene has no effect, so the carrier mobility of pyrene is the highest. 3) based on benzothiadiazole as the receptor unit, Polymers PCBT and PPOCBT were synthesized by using carbazole and carbazole modified by alkyl terminal pyrene as donor units respectively. The effects of pyrene modification on the photoabsorption, electrochemistry and optoelectronic properties of the polymer were systematically investigated. It was found that the pyrene group had little effect on the properties of the polymer with carbazole and benzothiadiazole as main chain units. This may be attributed to the weak intramolecular charge transfer and disordered aggregation of the main chain of the polymer, which makes it difficult for the pyrene group to bridge. Because the two kinds of polymers and fullerene derivatives can be blended to obtain a more uniform blend film, the photoelectric conversion efficiency of the two polymers is not different.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O631;TB33

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