有机太阳能电池供体材料的设计和理论研究

发布时间：2018-04-14 10:23

本文选题：有机太阳能电池 + 供体材料　；参考：《西南大学》2017年硕士论文

【摘要】：本文的主要研究目的设计高性能的有机太阳能电池供体材料,通过密度泛函理论(Density Functional Theory,DFT)以及含时密度泛函理论(Time Dependent Density Functional Theory,TDDFT)在高斯09程序下从理论上研究了一系列有机聚合物及小分子化合物的光电性质。基于大量的文献查阅,设计了一系列有潜力的高性能光伏材料,并在理论上对其电子性质、光学性质、光伏性质等进行了对比研究。经过理论的分析和预测,为有机太阳能电池供体材料的合成和发展提供思路和方向。第一节介绍了有机太阳能电池的工作原理,发展历程,以及近年来的研究现状。同时也从太阳能电池供体的角度分析了该领域的研究方向,对供体材料的进一步发展做了展望。陈述了选择该课题的理由以及本文工作的重点及亮点。第二节介绍了在本文的研究中运用到的理论计算方法,密度泛函理论以及含时密度泛函理论,对常用方法和基本原理进行了简要陈述。同时,还对Marcus电荷转移理论在电子转移的研究中的相关应用做了简要介绍。第三节研究了基于苯并二噻吩(BDT)基团的二维供体-受体(D-A)共聚物,这类聚合物具有显著的供体性质。是一类有潜能的高效本体异质结(BHJ)有机太阳能电池供体材料,可通过侧链基团的修饰对其性能进行优化。本节在实验分子P0(PBDTP-DTBT)的基础之上,通过吸电子基团对其侧链基团的取代设计了四种新聚合物P1-P4,主要研究了对BDT基团的影响。在这里,我们通过引入有效的吸电子部分,如:二嗪,均三嗪和四嗪对这个系统的电子性能的影响进行探讨。我们的计算结果表明,相对于太阳能电池应用,设计的聚合物P1-P4显示出比P0更好的光电子性能,例如:较低的HOMO能级,较窄的带隙,较小的重组能,较强的和较宽的吸收光谱和更高的电荷迁移率。此外,我们发现取代基的吸电子能力的增加同样有利于聚合物的电荷迁移率以及其吸收光谱的增强。第四节本节利用DFT和TD-DFT理论,在高性能小分子供体材料DRCN5T的基础之上,对其结构进行优化调整。首先,本节考虑了末端基团的优化,在分子两端分别引入缺电子和富电子基团,探讨该基团的引入对该小分子供体材料的影响,并从电子性质、光学性质、电荷传输性质等多方面进行了对比研究。此外,DRCN5T为U型小分子材料,为了使其线性更佳,本节在不改变其结构组成,只调整基团位置的情况之下调整其线性,并对线性和U型分子的电子性质、光学性质、电荷传输性质等多方面进行了对比研究。基于这些研究,对结果进行总结发现,末端富电子基团的引入,将结构调整为线性都能在一定程度上优化材料的性能。线性分子的性能提升明显,相较于原材料,拥有更优良的电子性质,更宽而强的吸收以及更好的电荷传输性质等。研究结果表明,改变基团位置来优化分子的结构及性能,可考虑作为此类研究中一种有效的方法。第五节本节主要在理论水平下对PTPD3T有机太阳能电池供体材料进行了新的设计研究,综合考虑了分子的对称性以及末端基团对小分子供体材料的影响。研究在其侧边加入三个噻吩,使其成为轴对称结构,又考虑在轴对称结构的基础之上在两端同时引入常用的缺电子单元,设计成新的供体材料。利用DFT和TD-DFT理论对这一系列材料的电子性质、光学性质以及电荷传输性质进行计算模拟,从理论上对比了这三个供体材料的光伏性能。结果表明,调整对称性,加入端基缺电子基团都能较好的调整供体的性能。最后,我们希望我们的工作将为有机太阳能电池的理论和实验的进一步研究提供有益的指导。
[Abstract]:The donor material of organic solar cells the main purpose of this paper is to design a high performance, the density functional theory (Density Functional Theory, DFT) and time-dependent density functional theory (Time Dependent Density Functional Theory, TDDFT) in the Gauss 09 program to study the optical properties of a series of organic polymer and small molecular compounds from lots of theory. Based on the literature review, the design of a series of potential high performance photovoltaic materials, and in theory on the electronic properties, optical properties and photovoltaic properties were studied. Through the analysis and prediction theory, provide ideas and directions for the synthesis and development of organic solar cell donor material. The first section introduces the working principle of organic solar cell development, and the research status in recent years. At the same time from the solar cell donor is analyzed in the field Research on the further development of donor materials was prospected. The statement of the topic and the reason for this work focus and highlights. The second section introduces the calculation method used in this study in theory, density functional theory and time-dependent density functional theory, the basic principle and methods of a brief statement at the same time, also give a brief introduction of Marcus charge transfer related theory is applied in the study of electron transfer in the third section. Based on Benzo (BDT) thiophene two groups of two-dimensional donor acceptor (D-A) copolymer, this polymer has significant donor properties. Is a kind of efficient bulk heterojunction potential node (BHJ) donor material of organic solar cell, to optimize its performance by modifying the side chain groups. This section in experimental molecular P0 (PBDTP-DTBT) on the basis of the electron withdrawing groups on the side chain The group replaced the designed four new polymer P1-P4, mainly studies the influence on the BDT group. Here, we introduce the effective electron withdrawing part, such as: two discussed the influence on the electronic properties of three and four were in this system. The simulation results show that compared with the solar cell application of polymer P1-P4 design shows better performance than optoelectronic P0, such as: low HOMO energy levels, with a narrow band gap, small reorganization energy, strong and wide absorption spectrum and high charge mobility. In addition, we found that the increase of electron withdrawing substituents have the same ability the charge transfer rate for polymer and its enhanced absorption spectrum. Fourth of this section by using DFT and TD-DFT theory, based on the high performance small molecule donor materials of DRCN5T, to adjust and optimize the structure. First of all, this section considers the end group Group optimization, respectively introducing electron deficient and electron rich groups in molecular ends, to introduce the group effect on the small molecule donor material, and from the electronic properties, optical properties, makes a comparative study on charge transport properties and other aspects. In addition, DRCN5T U small molecular materials, in order to make the better linear in this section, does not change its structure, under the adjustment of the location of the adjustment of the linear group, and electronic properties of linear and U type molecular optical properties, makes a comparative study on charge transport properties and other aspects. Based on these studies, the results were concluded that introduction of electron rich groups at the end of the performance the structure adjustment is linear can optimize material to a certain extent. The performance of linear molecules increases significantly, compared to the raw material, has excellent electronic properties, wide and strong absorption and better charge transport properties Quality. The results show that the change of group position to optimize the structure and properties of molecules, such as research in an effective way. This section mainly consider fifth in the level of theory of PTPD3T organic solar cell donor materials for the design and research of the new, considering the influence of molecular symmetry and end groups the small molecule donor material. On its side to join three thiophene, make it become a symmetric structure, and on the basis of considering axisymmetric structures at both ends while introducing electron deficient unit commonly used, designed for new material. Using DFT and TD-DFT theory of electronic properties of a series of materials and the optical properties and charge transport properties were calculated theoretically, compared to the three of the photovoltaic properties of donor materials. The results show that the adjustment of symmetry, join terminal electron deficient groups can In the end, we hope that our work will provide useful guidance for further research on the theory and experiments of organic solar cells.

【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM914.4

【参考文献】