Sneyd Alexander J, Beljonne David, Rao Akshay
Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom.
Laboratory for Chemistry of Novel Materials, University of Mons, Mons 7000, Belgium.
J Phys Chem Lett. 2022 Jul 28;13(29):6820-6830. doi: 10.1021/acs.jpclett.2c01133. Epub 2022 Jul 20.
Efficient exciton transport is crucial to the application of organic semiconductors (OSCs) in light-harvesting devices. While the physics of exciton transport in highly disordered media is well-explored, the description of transport in structurally and energetically ordered OSCs is less established, despite such materials being favorable for devices. In this Perspective we describe and highlight recent research pointing toward a highly efficient exciton transport mechanism which occurs in ordered OSCs, transient delocalization. Here, exciton-phonon couplings play a critical role in allowing localized exciton states to temporarily access higher-energy delocalized states whereupon they move large distances. The mechanism shows great promise for facilitating long-range exciton transport and may allow for improved device efficiencies and new device architectures. However, many fundamental questions on transient delocalization remain to be answered. These questions and suggested next steps are summarized.
高效的激子传输对于有机半导体（OSC）在光捕获器件中的应用至关重要。虽然在高度无序介质中激子传输的物理过程已得到充分研究，但对于结构和能量有序的有机半导体中传输的描述却不太完善，尽管这类材料对器件有利。在这篇观点文章中，我们描述并强调了最近的研究，这些研究指向一种在有序有机半导体中发生的高效激子传输机制——瞬态离域。在这里，激子 - 声子耦合在使局域激子态能够暂时进入更高能量的离域态从而实现长距离移动方面起着关键作用。该机制在促进长程激子传输方面显示出巨大潜力，并可能带来更高的器件效率和新的器件架构。然而，关于瞬态离域仍有许多基本问题有待解答。本文总结了这些问题及建议的后续步骤。
