Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.
PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan.
Science. 2021 Jul 2;373(6550):95-98. doi: 10.1126/science.abg8790.
Ways to characterize and control excited states at the single-molecule and atomic levels are needed to exploit excitation-triggered energy-conversion processes. Here, we present a single-molecule spectroscopic method with micro-electron volt energy and submolecular-spatial resolution using laser driving of nanocavity plasmons to induce molecular luminescence in scanning tunneling microscopy. This tunable and monochromatic nanoprobe allows state-selective characterization of the energy levels and linewidths of individual electronic and vibrational quantum states of a single molecule. Moreover, we demonstrate that the energy levels of the states can be finely tuned by using the Stark effect and plasmon-exciton coupling in the tunneling junction. Our technique and findings open a route to the creation of designed energy-converting functions by using tuned energy levels of molecular systems.
需要能够在单分子和原子水平上对激发态进行特征化和控制，以利用激发触发的能量转换过程。在这里，我们提出了一种使用激光驱动纳米腔等离子体的单分子光谱方法，该方法具有微电子伏特能量和亚分子空间分辨率，可在扫描隧道显微镜中诱导分子发光。这种可调谐且单色的纳米探针允许对单个分子的单个电子和振动量子态的能级和线宽进行选择性的特征化。此外，我们证明通过在隧道结中使用斯塔克效应和等离子体激元-激子耦合，可以精细地调整这些态的能级。我们的技术和发现为通过调整分子系统的能级来创建设计的能量转换功能开辟了道路。
