Molecular junctions are building blocks for constructing future nanoelectronic devices that enable the investigation of a broad range of electronic transport properties within nanoscale regions. Crossing both the nanoscopic and mesoscopic length scales, plasmonics lies at the intersection of the macroscopic photonics and nanoelectronics, owing to their capability of confining light to dimensions far below the diffraction limit. Research activities on plasmonic phenomena in molecular electronics started around 2010, and feedback between plasmons and molecular junctions has increased over the past years. These efforts can provide new insights into the near-field interaction and the corresponding tunability in properties, as well as resultant plasmon-based molecular devices. This Review presents the latest advancements of plasmonic resonances in molecular junctions and details the progress in plasmon excitation and plasmon coupling. We also highlight emerging experimental approaches to unravel the mechanisms behind the various types of light–matter interactions at molecular length scales, where quantum effects come into play. Finally, we discuss the potential of these plasmonic–electronic hybrid systems across various future applications, including sensing, photocatalysis, molecular trapping and active control of molecular switches.

分子结是构建未来纳米电子设备的基石，能够研究纳米级区域内广泛的电子传输特性。跨越纳米和介观长度尺度，等离子体位于宏观光子学和纳米电子学的交叉点，因为它们能够将光限制在远低于衍射极限的尺寸。分子电子学中等离子体现象的研究活动始于 2010 年左右，等离子体和分子连接之间的反馈在过去几年有所增加。这些努力可以为近场相互作用和相应的特性可调性以及由此产生的基于等离子体的分子装置提供新的见解。本综述介绍了分子连接中等离子体共振的最新进展，并详细介绍了等离子体激发和等离子体耦合的进展。我们还强调了新兴的实验方法，以揭示量子效应发挥作用的分子长度尺度上各种类型的光-物质相互作用背后的机制。最后，我们讨论了这些等离子体-电子混合系统在未来各种应用中的潜力，包括传感、光催化、分子捕获和分子开关的主动控制。