【作者】 李浩源； 段炼； 孙永铎； 邱勇；

【Author】 Haoyuan Li;Lian Duan;Yongduo Sun;Yong Qiu;Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education,Department of Chemistry,Tsinghua University;

【机构】 有机光电子与分子工程教育部重点实验室,清华大学化学系；

【摘要】 对于无定形材料,分子结构与宏观的迁移率之间的关系还不清楚。传统的计算迁移率的方法往往包含很多经验参数,这不利于深入了解一种有机半导体的传输特性。我们用波恩-奥本海默(BOMD)分子动力学模拟了一种常用的小分子主体材料9,10-二(2-萘基)蒽(ADN)的无定形结构,并用第一性原理的非绝热的分子动力学(NAMD)计算了不同分子之间的载流子传输速率,最后利用求解主方程的方法计算了它的空穴和电子迁移率。我们的计算过程参照了Lu课题组的方法[1],不同的是,在计算中,我们考虑了镜像轨道之间的作用,提高了在BOMD的结果上计算分子之间非绝热耦合的精度[2]。最终计算出的空穴和电子迁移率与用飞行时间法测试得到的结果十分接近。另一方面,计算出的空穴和电子的迁移率有相近的场强依赖性,这跟ADN具有的非给体-受体结构相吻合。我们的研究也表明这种第一性原理的方法有希望用来预测无定形有机半导体材料的迁移率。更多还原

【Abstract】 The relationship between molecular structure and the charge transport properties of amorphous organic semiconductors is not clear. This brings difficulty in the design of better materials and device optimizations. Here, Born-Oppenheimer molecular dynamics(BOMD) is used to simulate the amorphous structure of a widely used small molecule 9,10-di-(2’-naphthyl)anthracene(ADN). The charge transfer rate between molecules is calculated via non-adiabatic molecular dynamics(NAMD). Its hole and electron mobilities are then calculated by the master equation. The theoretical algorithm is similar to Lu’s method. However, we took the contribution of mirror orbitals into account when calculate the charge transfer rate, which would reduce the error brought by the finite system size. The calculated hole and electron mobilities both have the same order of magnitude with their corresponding experimental results, demonstrating the possibility to obtain reasonable charge transport mobilities for amorphous small-molecule semiconductors via the first-principles approach.更多还原