Physics Department E20 , Technical University of Munich , James-Franck-Str. 1 , 85748 Garching , Germany.
Institute of Physics , Chinese Academy of Sciences , 100190 Beijing , P.R. China.
J Am Chem Soc. 2018 Apr 11;140(14):4835-4840. doi: 10.1021/jacs.7b12818. Epub 2018 Mar 22.
Precisely controlling well-defined, stable single-molecule junctions represents a pillar of single-molecule electronics. Early attempts to establish computing with molecular switching arrays were partly challenged by limitations in the direct chemical characterization of metal-molecule-metal junctions. While cryogenic scanning probe studies have advanced the mechanistic understanding of current- and voltage-induced conformational switching, metal-molecule-metal conformations are still largely inferred from indirect evidence. Hence, the development of robust, chemically sensitive techniques is instrumental for advancement in the field. Here we probe the conformation of a two-state molecular switch with vibrational spectroscopy, while simultaneously operating it by means of the applied voltage. Our study emphasizes measurements of single-molecule Raman spectra in a room-temperature stable single-molecule switch presenting a signal modulation of nearly 2 orders of magnitude.
精确控制明确、稳定的单分子结是单分子电子学的一个支柱。早期尝试利用分子开关阵列进行计算的部分挑战是金属-分子-金属结的直接化学表征的限制。虽然低温扫描探针研究已经推进了电流和电压诱导构象转换的机制理解，但金属-分子-金属构象仍然主要是从间接证据推断出来的。因此，开发稳健的、对化学敏感的技术对于该领域的发展至关重要。在这里，我们通过施加电压的方式，同时利用振动光谱技术来探测一个两态分子开关的构象。我们的研究强调了在室温稳定的单分子开关中测量单分子拉曼光谱，该开关的信号调制幅度接近 2 个数量级。
