Laboratory for Nanosystem and Hierarchy Fabrication, CAS Center for Excellence in Nanoscience , National Center for Nanoscience and Technology , Beijing 100084 , People's Republic of China.
Department of Chemistry , Capital Normal University , Beijing 100048 , People's Republic of China.
J Chem Theory Comput. 2019 Mar 12;15(3):1477-1491. doi: 10.1021/acs.jctc.8b00779. Epub 2019 Feb 11.
Despite great attention to the charge transport in organic semiconductors (OSC) over the last decades, the underlying mechanism is still controversial. After our theoretical position in 2009, the quantum nuclear tunneling effect has been proven by more and more experiments to play an essential role for charge transport in organic and polymeric materials. On the other hand, back in the 1970s, it was proposed that the nature of charge transport could be analyzed by the isotope effect, which, however, has not been confirmed either experimentally or theoretically. In this Perspective, we review the understanding of microscopic mechanisms on charge transport by using different transport mechanisms from hopping to band transport. Particularly, we point out that the isotope effect, which is absent in the semiclassical Marcus theory, should be negative for the localized charge transport with quantum nuclear tunneling. We conclude that the quantum nuclear tunneling effect dominates the charge transport in OSCs.
尽管过去几十年来人们对有机半导体（OSC）中的电荷输运给予了极大关注，但基本机制仍存在争议。自 2009 年我们的理论立场以来，量子核隧穿效应已被越来越多的实验证明对有机和聚合材料中的电荷输运起着至关重要的作用。另一方面，早在 20 世纪 70 年代，就有人提出可以通过同位素效应来分析电荷输运的性质，但无论是实验上还是理论上都没有得到证实。在本观点中，我们通过使用从跳跃到能带输运的不同输运机制来回顾对电荷输运微观机制的理解。特别地，我们指出，在半经典 Marcus 理论中不存在的同位素效应对于具有量子核隧穿的局域电荷输运应该是负的。我们得出的结论是，量子核隧穿效应主导了 OSCs 中的电荷输运。
