高性能空穴传输材料的计算机辅助设计
毕业论文关键词 空穴传输材料 电子密度泛函 HOMO能级 空穴重组能 紫外可见光谱
Title Computer-aided Design of Organic Hole Transport Materials
Abstract The storage and efficient conversion of energy is very important for modern society. Organic-inorganic perovskite solar cells (PSCs) based on organic hole transport materials (HTMs) have attracted wide interest due to their high power conversion efficiency which exceeds 20%.The hole transport layer is a key component of PSCs and is critical to improve the stability and energy conversion efficiency of the battery. Thus the performance of the HTMs filled in the hole transport layer is particularly important. The goal of this work is to design high quality HTMs. To achieve this goal, we calculate two properties, i.e. HOMO energy level and hole reorganization energy, of 7 molecules in order to screen out the most appropriate molecule. The hole reorganization energy is calculated based on electron transfer theory. We carry out first principles density functional theory calculation to determine those two properties of various molecules. We find TET is a particular promising molecule. Its HOMO energy level is -4.33 (eV), while its hole reorganization energy is 113 (meV). Both properties match the expected ideal values. Now TET is under synthesis for verification of its functions by an experimental group.
Keywords Organic hole transport material Density functional theory (DFT) Hole reorganization energy HOMO TD-DFT
目次
1引言…1
1.1研究背景1
1.2研究意义…1
1.3研究内容…2
2研究方法…4
2.1分子模型构建与优化4
2.2HOMO,LUMO能级计算5
2.3空穴重组能计算…5
3结果分析…7
3.1优化结构分析7
3.2HOMO能级分析…11
3.3空穴重组能分析11
3.4总结…12
4紫外可见光谱的计算…13
结论…14
致谢…15
参考文献16
附录18
1 引言 1.1 研究背景 2009年，Miyasaka等[1]首次以有机-无机杂化的卤素钙钛矿CH3NH3PbI3作为光敏材料用于太阳能电池，收获了3.8%的光电转换效率(power conversion efficiency , PCE)。此后，钙钛矿太阳能电池得到迅速发展，光电转换效率飙升，被Science 评为“2013 年十大科学突破”之一。 CH3NH3PbI3 在电解液中的易分解、稳定性差。 2012 年， Kim 等 [2]用2,2',7,7'-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene(spiro-MeOTAD)作为空穴传输层材料(Hole transport material，HTM)代替电解液，制得基于CH3NH3PbI3的固态介观敏化电池，PEC提升到9.7%。HTM的引入，极大的提高了电池的稳定性。但是Spiro-MeOTAD制作工艺复杂，价格为黄金的10倍[3]，不利于商业化发展。一批新型的HTM被研发，包括：无机材料、有机小分子、聚合物等。2015 年，Yang 等[5]以 NH2CH=NH2PbI3 为光敏材、Poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine](PTAA)为 HTM 制得的钙钛矿太阳能电池 PCE突破20%。 分子模拟[4]，是指利用理论方法与计算技术，模拟或仿真分子运动的微观行为，广泛的应用于计算化学，计算生物学，材料科学领域，小至单个化学分子，大至复杂生物体系或材料体系都可以是它用来研究的对象。随着计算机软件、硬件的发展。特别是计算机速度的飞速提高，分子模拟技术不仅可以模拟静态分子的体系结构，还可以它用来模拟分子体系的动力学行为。
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