State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering & Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen, China.
Department of Physics, Lancaster University, Lancaster, UK.
Nat Mater. 2019 Apr;18(4):364-369. doi: 10.1038/s41563-018-0265-4. Epub 2019 Feb 11.
Controlling the electrical conductance and in particular the occurrence of quantum interference in single-molecule junctions through gating effects has potential for the realization of high-performance functional molecular devices. In this work we used an electrochemically gated, mechanically controllable break junction technique to tune the electronic behaviour of thiophene-based molecular junctions that show destructive quantum interference features. By varying the voltage applied to the electrochemical gate at room temperature, we reached a conductance minimum that provides direct evidence of charge transport controlled by an anti-resonance arising from destructive quantum interference. Our molecular system enables conductance tuning close to two orders of magnitude within the non-faradaic potential region, which is significantly higher than that achieved with molecules not showing destructive quantum interference. Our experimental results, interpreted using quantum transport theory, demonstrate that electrochemical gating is a promising strategy for obtaining improved in situ control over the electrical performance of interference-based molecular devices.
通过门控效应控制单分子结的电导，特别是量子干涉的出现，有望实现高性能功能分子器件。在这项工作中，我们使用电化学门控、机械可控的断裂结技术来调节噻吩基分子结的电子行为，这些分子结表现出破坏性量子干涉特征。通过改变室温下施加在电化学门上的电压，我们达到了电导的最小值，这直接证明了电荷输运受到破坏性量子干涉产生的反共振的控制。我们的分子系统能够在非法拉第电位区域内调谐两个数量级的电导，这明显高于那些没有表现出破坏性量子干涉的分子所能达到的水平。我们的实验结果，使用量子输运理论进行解释，表明电化学门控是一种很有前途的策略，可以在原位获得对基于干涉的分子器件的电性能的改进控制。
