聚（3-己基噻吩）及其嵌段共聚物的自组装和光电应用

发布时间：2018-03-07 09:14

  本文选题：共轭高分子　切入点：拉直碳纳米管　出处：《浙江大学》2017年博士论文　论文类型：学位论文

【摘要】：共轭高分子由于其刚性分子链结构和较强的分子间相互作用,因而具有较好的结晶性和优异的光电性能,被广泛应用于光电领域中。本文以聚(3-己基噻吩)(P3HT)及含P3HT的嵌段共聚物为研究对象,研究共轭高分子与同样具有共轭结构的碳纳米管(CNTs)之间的相互作用、共轭高分子有序自组装的性质和作为有机给体材料在水相制备太阳能电池的应用。伸直的CNTs对含CNTs的材料和器件性能的提升都具有重要的意义。本论文首先发现,P3HT可在单壁碳纳米管(SWCNTs)表面外延结晶形成晶须,在合适的条件下能显著地拉直SWCNTs。改变P3HT溶液结晶条件,发现低浓度的SWCNTs和较高的SWCNT/P3HT质量比有利于弯曲的SWCNTs被拉直。实验发现,在溶液中P3HT分子链就可附着在SWCNTs管壁表面,从而对SWCNTs产生拉直作用,而非由外延结晶形成的P3HT纳米纤维晶体驱动SWCNTs拉直。用X-射线光电子能谱、紫外吸收光谱和光致发光光谱光谱进一步揭示了复合物的内在作用机理,发现P3HT分子链和SWCNTs之间存在强的π-π相互作用,使SWCNTs的持续长度得到显著增强。P3HT对SWCNTs的拉直效应较弱,会被SWCNTs之间的缠绕和桥连导致的局部应力抵消,这在高浓度的SWCNTs和低的SWCNT/P3HT质量比条件下能观察到,P3HT也难以拉直弯曲模量较大的MWCNTs。控制共轭聚合物从微观尺度到宏观尺度的形貌是一个很关键的技术挑战,聚合物的聚集态形貌影响着相应器件的性能,进而影响共轭聚合物在电子设备上的应用推广。本论文考虑到P3HT分子链较强的结晶性,将P3HT溶液滴涂在基底上,受三相界面处溶剂挥发影响,结晶形成纤维。通过调控外界的结晶条件,促使P3HT分子链有序堆积形成纤维,并通过倾斜基底提供外界应力,诱导P3HT纤维有序取向,形成高度取向的纤维阵列薄膜。通过掠入射小角X-射线散射和偏振紫外可见光吸收光谱,发现P3HT分子链在纤维阵列中的排列结构主要是“侧立”结构,主链方向与纳米纤维垂直。取向的纳米纤维阵列,作为导电网络应用于有机场效应晶体管,能显著地提升载流子迁移率。聚合物分子链的有序堆积,纤维紧密排列和高度取向,都有利于提高薄膜的载流子迁移率。本工作制备取向P3HT纤维薄膜的方法简单高效,对共轭聚合物在电子器件中的应用有极其重要的意义。含P3HT的双亲性嵌段共聚物能在选择性溶剂水中可进行自组装,形成有序的纳米胶束结构。同时由于P3HT是半导体高分子,因此含P3HT的双亲性嵌段共聚物可望应用于水相制备太阳能电池。本论文合成了聚(3-已基噻吩)-b-聚丙烯酸(P3HT-b-PAA)双亲性嵌段共聚物,并研究其在水溶液中自组装成胶束的形貌,发现通过加入P3HT均聚物,胶束由球状或棒状转化为纤维状。将胶束与水溶性的CdTe纳米晶复合,应用到太阳能电池中,发现P3HT-b-PAA双亲性嵌段共聚物的引入能显著改善复合物的光电性能与薄膜的形貌。本论文通过嵌段共聚物胶束和水溶性纳米晶水相制备杂化太阳能电池,最高效率能达到4.8%,为洁净和低成本制备高效太阳能电池提供了一种思路。
[Abstract]:Conjugated polymer interactions due to the rigid molecular chain structure and strong intermolecular, so it has good crystallinity and excellent optical properties, is widely used in photoelectric field. Based on poly (hexylthiophene 3-) (P3HT) and P3HT containing block copolymer as the object of the study of the conjugated polymer with the same the conjugate structure of carbon nanotubes (CNTs) interaction between the conjugated polymer ordered properties of self assembly and application as organic donor materials in aqueous preparation of solar cells. The extension of CNTs is of great significance to material containing CNTs and device performance promotion. This paper first found in P3HT single walled carbon nanotubes (SWCNTs) surface of epitaxial crystal whisker formation, can significantly change the crystallization conditions straightened SWCNTs. P3HT solution under suitable conditions, we found that low concentrations of SWCNTs and higher SWCNT/ P3HT than the good quality In the bending of SWCNTs be straightened. The experimental results showed that, in the solution of P3HT molecular chain can be attached on the surface of the SWCNTs tube wall, resulting in straightening effect on SWCNTs, rather than by the epitaxial crystallization of P3HT nano fiber crystal formation SWCNTs straight. Driven by X- ray photoelectron spectroscopy, UV absorption spectroscopy and photoluminescence spectroscopy spectroscopy further reveals the intrinsic mechanism of the complexes, found strong pi pi interactions between the molecular chains of P3HT and SWCNTs, the length of SWCNTs can be significantly enhanced to straighten out the effect of.P3HT on SWCNTs is weak, SWCNTs will be between the winding and bridge caused by local stress offset, the observed in high the concentration of SWCNTs and low SWCNT/P3HT ratio to P3HT, it is difficult to straighten the flexural modulus of the larger MWCNTs. control of conjugated polymers from micro scale to macro scale morphology is a key technical challenge, Morphology of the polymer affects the properties of corresponding devices, thereby affecting the popularization and application of conjugated polymers in electronic devices. In this dissertation, considering the crystallization of P3HT molecular chain is strong, the P3HT solution is coated on the substrate, the three-phase interface effect of solvent evaporation, crystallization to form fibers. Through crystallization conditions control outside. The P3HT chain ordered to form fibers and provide external stress by tilting the substrate induced ordered orientation of P3HT fiber, fiber array film to form a highly oriented. By grazing incidence small angle X- ray scattering and polarized UV visible light absorption spectrum, P3HT molecular chain structure in the fiber array is the main side "stand structure, main direction and nano fiber. The vertical orientation of the nano fiber array, as a conductive network used in organic field-effect transistors, can significantly enhance carrier mobility. The polymer chains ordered, fibers were closely packed and highly oriented, it is beneficial to improve film carrier mobility. The orientation of the P3HT thin films by the fiber working system is simple and efficient, has important significance for the application of conjugated polymers in electronic devices. The amphiphilic block copolymers in selective solvent can be water the self-assembled into nano micelles containing P3HT, ordered structure. At the same time, because P3HT is a semiconductor polymer, the amphiphilic block copolymers containing P3HT can be used in aqueous preparation of solar cells. This paper synthesized poly (3- thiophene) -b- polyacrylic acid (P3HT-b-PAA) amphiphilic block copolymers, and study the in aqueous solution self assemble into micelle morphology, found by the addition of P3HT homopolymer, micelles transformed from spherical or rod like fibers. The micelle and water-soluble CdTe nanocrystal composite application. The solar cell, found that P3HT-b-PAA amphiphilic block copolymers are introduced and the photoelectric properties of films can significantly improve the complex morphology. The block copolymer micelle and water preparation of hybrid solar cell soluble nanocrystals in aqueous system, the highest efficiency can reach 4.8%, which provides a new way for clean and low cost system preparation of highly efficient solar cells.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O633.5
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本文编号：1578804