有机太阳能电池给受体界面激子复合过程的理论研究

发布时间：2018-09-17 15:24

【摘要】：有机太阳能电池给受体界面激子复合会影响其光电转换效率,从而影响电池的性能,所以对界面激子复合的研究非常重要。本文以密度泛函理论(density functional theory,DFT)和含时密度泛函理论(time-dependent density functional theory,TDDFT)为理论基础,对有机太阳能电池给受体界面:有机平面小分子/富勒烯界面并五苯(pentacene)/富勒烯(fullerene,C60),染料分子/富勒烯界面酞菁(phthalocyanine,Pc)/富勒烯,酞菁铜(copper phthalocyanine,Cu Pc)/富勒烯以及有机聚合物/富勒烯界面4-聚噻吩(4-poly thiophene,T4)/富勒烯,6-聚噻吩(6-poly thiophene,T6)/富勒烯进行界面激子复合的理论研究。对给体分子Pentacene,Pc,Cu Pc,T4,T6和受体分子C60分子进行构型优化,再构建并优化Pentacene/C60界面、Pc/C60界面、Cu Pc/C60界面、T4/C60界面和T6/C60界面后,进行一系列计算。计算轨道能级并分析。300 K温度下对五对界面进行玻恩—奥本海默分子动力学模拟,构型演化以及轨道能级演化结果表明五对界面都达到了动力学平衡,说明300 K时五对界面构型的稳定合理性。通过范围分割的含时密度泛函理论(range-separated time-dependent density functional theory,range-separated TDDFT),计算不同时刻界面构型下的激发态能量和电荷密度。通过傅里叶变换公式处理所有动力学构型下给受体界面的最低激发态能量,得到各个界面的声子模式,分析了影响五对界面激子复合的主要振动模式。最后通过非绝热从头算分子动力学方法计算得出最低激发态复合到基态的时间变化关系,以此说明界面激子复合。激子复合速率Cu Pc/C60界面的激子复合最快,而Pc/C60和T6/C60界面的激子复合最慢。研究结果表明,Pentacene/C60界面激子复合不会对太阳能电池的性能产生影响,金属铜会大大加速激子的复合,增加聚合物的聚合度可以减慢激子复合。
[Abstract]:Organic solar cells give acceptor interface exciton recombination will affect its photoelectric conversion efficiency, thus affecting the performance of the battery, so the study of interface exciton recombination is very important. This paper is based on density functional theory (density functional theory,DFT) and time-dependent density functional theory (time-dependent density functional theory,TDDFT). For organic solar cells, the receptor interface: organic plane small molecule / fullerene interface pentaphenyl (pentacene) / fullerene (fullerene,C60), dye molecule / fullerene interface phthalocyanine (phthalocyanine,Pc) / fullerene, The interfacial exciton recombination of copper phthalocyanine (copper phthalocyanine,Cu Pc) / fullerene and organic polymer / fullerene interfacial 4-polythiophene (4-poly thiophene,T4) / fullerene 6-polythiophene (6-poly thiophene,T6) / fullerene was studied theoretically. The configuration of donor molecule Pentacene,Pc,Cu Pc,T4,T6 and receptor molecule C60 was optimized, and a series of calculations were carried out after the Pentacene/C60 interface was constructed and optimized, the interface of Cu Pc/C60 and the interface of T 4 / C 60 and C 60 were optimized. The calculation of orbital energy levels and the analysis of five pairs of interfaces at .300K are carried out in the Boson-Oppenheimer molecular dynamics simulation. The results of configuration evolution and orbital energy level evolution show that the five pairs of interfaces have achieved dynamic equilibrium. The stability and rationality of the five pairs of interfacial configurations at 300 K are demonstrated. The time-dependent density functional theory (range-separated time-dependent density functional theory,range-separated TDDFT),) is used to calculate the excited state energy and charge density at different time interface configurations. Using Fourier transform formula to deal with the lowest excited state energy of the acceptor interface under all dynamic configurations, the phonon modes of each interface are obtained, and the main vibration modes affecting the recombination of five excitons are analyzed. Finally, the time-varying relationship between the lowest excited state and the ground state is calculated by using the non-adiabatic ab initio molecular dynamics method, which explains the interfacial exciton recombination. The exciton recombination rate at Cu Pc/C60 interface is the fastest, and the exciton recombination at Pc/C60 and T6/C60 interface is the slowest. The results show that the interfacial exciton recombination at Pentacene / C60 interface has no effect on the performance of solar cells. Metal copper can accelerate exciton recombination greatly and increase polymerization degree of polymer can slow down exciton recombination.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM914.4

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