The dark side of energy transport along excitonic wires: On-site energy barriers facilitate efficient, vibrationally mediated transport through optically dark subspaces.
The dark side of energy transport along excitonic wires: On-site energy barriers facilitate efficient, vibrationally mediated transport through optically dark subspaces.
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DOI：
10.1063/5.0023702
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发表时间：
2020-07
期刊：
影响因子：
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通讯作者：
S. Davidson;A. Fruchtman;F. A. Pollock;E. Gauger
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文献类型：
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作者：
S. Davidson;A. Fruchtman;F. A. Pollock;E. Gauger
我们提出了一种新颖的、反直觉的方法，基于暗态保护，可以显著提高激子通过由具有固有能量梯度的分子位点链组成的“线”的传输效率。具体来说，通过在输运路径上以规则的间隔向能量景观引入“屏障”，我们发现由于系统中亚辐射和超辐射本征态的明显分离，不良的辐射重组过程被抑制。这反过来又可以使传输功率提高许多个数量级，即使对于很长的链也是如此。从那里，我们分析了这种现象对系统和环境特性变化的鲁棒性，以表明这种效应在一系列不同的热和光学环境制度中是有益的。最后，我们表明，这里提出的新型能量格局可能为克服短长度尺度提供有用的基础，短长度尺度是有机光伏和其他纳米级传输场景中激子扩散的典型特征，从而导致此类设备效率的巨大潜在改进。
We present a novel, counter-intuitive method, based on dark-state protection, for significantly improving exciton transport efficiency through "wires" comprising a chain of molecular sites with an intrinsic energy gradient. Specifically, by introducing "barriers" to the energy landscape at regular intervals along the transport path, we find that undesirable radiative recombination processes are suppressed due to a clear separation of sub-radiant and super-radiant eigenstates in the system. This, in turn, can lead to an improvement in transmitted power by many orders of magnitude, even for very long chains. From there, we analyze the robustness of this phenomenon to changes in both system and environment properties to show that this effect can be beneficial over a range of different thermal and optical environment regimes. Finally, we show that the novel energy landscape presented here may provide a useful foundation for overcoming the short length scales over which exciton diffusion typically occurs in organic photo-voltaics and other nanoscale transport scenarios, thus leading to considerable potential improvements in the efficiency of such devices.