Probing the optical and charge transport characteristics in molecular junctions not only provides fundamental understanding of light–matter interactions and quantum transport at the atomic and molecular scale, but also holds great promise for the development of molecular-scale optical and electronic devices. Herein, an overview of recent progress in fabricating and characterizing photoswitching molecular systems using both the current measured from single molecule circuits as well as the light signals monitored in photodetectors is presented. We review four groups of azobenzene, diarylethene, dihydroazulene, spiropyran photoswitching molecules that have been used to construct photoswitching molecular devices by scanning tunneling microscope-based or mechanically controlled break-junction techniques, focusing on the impact of light-induced reactions on the charge transport processes at the single molecule level. We also discuss key optical properties of photoswitching systems, uncovered by a range of optical methods including transient absorption and ultrafast spectroscopies, that are critically related to structural symmetry or nonlinear optical effects.

中文翻译：

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光开关等离子体分子系统的光学和电荷传输特性


探测分子结中的光学和电荷传输特性不仅可以提供对原子和分子尺度上的光与物质相互作用和量子传输的基本理解，而且还为分子尺度光学和电子器件的发展带来了巨大的希望。本文概述了利用单分子电路测量的电流以及光电探测器监测的光信号来制造和表征光开关分子系统的最新进展。我们回顾了四组偶氮苯、二芳基乙烯、二氢甘菊环、螺吡喃光开关分子，这些分子已被用于通过基于扫描隧道显微镜或机械控制的断裂结技术构建光开关分子器件，重点关注光诱导反应对电荷传输的影响单分子水平上的过程。我们还讨论了光开关系统的关键光学特性，这是通过一系列光学方法（包括瞬态吸收和超快光谱学）发现的，这些特性与结构对称性或非线性光学效应密切相关。