有机太阳能电池内分子间载流子复合动力学研究
Study on the Intermolecular Carrier Recombination Dynamics in Organic Solar Cells
李冲 1王美姣 1葛琳 1曹连振1
作者信息
- 1. 潍坊学院物理与电子信息学院,山东 潍坊 261061
- 折叠
摘要
基于载流子复合对有机太阳能电池光伏效率的重要影响,采用扩展的Su-Schrieffer-Heeger紧束缚模型结合非绝热量子动力学方法,对有机太阳能电池内的分子间载流子复合动力学进行理论研究.首先,模拟并揭示了正、负载流子在给/受体界面处的分子间电荷复合动力学过程,发现分子间的载流子复合表现为分数电荷复合并伴随能量的损失.随后,研究体系带阶Δ、电场、热效应和受体分子的聚集对分子间载流子复合动力学的影响.结果表明:体系带阶Δ表现为载流子的复合势垒,带阶越大越利于抑制载流子的复合.电场可以通过诱导正、负电荷的空间离域抑制载流子的复合,特别是,当电场足够强时可以将复合的电荷转移态解离为自由载流子.热效应会引起给/受体材料在位能的随机涨落,降低载流子的复合势垒,进而加剧载流子的复合.受体分子的聚集会诱导电子在受体分子之间的扩展,增大界面处正、负电荷中心的距离,从而抑制载流子的复合.
Abstract
Based on the important effect of carrier recombination on the photovoltaic efficiency of organic solar cells,the intermolecular carrier recombination dynamics in organic solar cells is studied theoretically by using an extended Su-Schrieffer-Heeger tight binding model combined with the non-adiabatic quantum dynamical method in this article.Firstly,intermolecular charge recombination dynamics of the positive and negative carriers at the donor/acceptor interface is simulated and revealed,and it is found that the intermolecular carrier recombination exhibits fractional charge recombination along with energy loss.Subsequently,influence of the system energy offset Δ,electric field,thermal effect and aggregation of acceptor molecules on intermolecular carrier recombination dynamics is studied.The results show that the system energy offset Δ exhibits the carrier recombination barrier,and the larger the energy offset Δ,the more favorable it is to suppress the recombination of carriers.The electric field can inhibit the recombination of carriers by inducing spatial delocalization of positive and negative charges.Especially,as the electric field is strong enough,it can dissociate the recombined charge transfer state into free carriers.Thermal effects can cause random fluctuations of the potential energy of the donor/acceptor material,which can reduce the recombination barrier of carriers,and further to aggravate the carrier recombination.The aggregation of acceptor molecules will induce the expansion of electrons between acceptor molecules,increasing the distance between positive and negative charge centers at the interface,thereby inhibiting the recombination of carriers.
关键词
有机太阳能电池/电荷转移态/载流子复合/能量损失Key words
organic solar cells/charge-transfer state/carrier recombination/energy loss引用本文复制引用
基金项目
山东省自然科学基金(ZR2021QA035)
潍坊市科技发展项目(2021GX010)
潍坊市高新区惠民计划(2021KJHM05)
出版年
2024
NETL
NSTL
万方数据