Kamerlingh Onnes Laboratorium, Leiden University, Niels Bohrweg 2, Leiden, The Netherlands.
J Phys Condens Matter. 2010 Apr 7;22(13):133001. doi: 10.1088/0953-8984/22/13/133001. Epub 2010 Mar 17.
We review the fascinating research on charge transport through switchable molecules. In the past decade, detailed investigations have been performed on a great variety of molecular switches, including mechanically interlocked switches (rotaxanes and catenanes), redox-active molecules and photochromic switches (e.g. azobenzenes and diarylethenes). To probe these molecules, both individually and in self-assembled monolayers (SAMs), a broad set of methods have been developed. These range from low temperature scanning tunneling microscopy (STM) via two-terminal break junctions to larger scale SAM-based devices. It is generally found that the electronic coupling between molecules and electrodes has a profound influence on the properties of such molecular junctions. For example, an intrinsically switchable molecule may lose its functionality after it is contacted. Vice versa, switchable two-terminal devices may be created using passive molecules ('extrinsic switching'). Developing a detailed understanding of the relation between coupling and switchability will be of key importance for both future research and technology.
我们回顾了关于通过可切换分子进行电荷传输的迷人研究。在过去的十年中，对各种分子开关进行了详细的研究，包括机械互锁开关（轮烷和索烃）、氧化还原活性分子和光致变色开关（如偶氮苯和二芳基乙烯）。为了探测这些分子，无论是单独探测还是在自组装单层（SAM）中，都开发了一系列广泛的方法。这些方法从低温扫描隧道显微镜（STM）通过双端断裂结到更大规模的基于 SAM 的器件不等。一般来说，人们发现分子和电极之间的电子耦合对这种分子结的性质有深远的影响。例如，一个固有的可切换分子在与电极接触后可能会失去其功能。反之，使用无源分子（“外在切换”）也可以创建可切换的两端器件。详细了解耦合和可切换性之间的关系对于未来的研究和技术都将是至关重要的。
