The Selective Routing of Plasmonic Interface Charge Transfer in Enhanced Raman Spectroscopy or Chemical Reaction

Plasmon-induced interface charge transfer has garnered enduring and widespread interest over the half century, starting from the chemical enhancement mechanism (CM) in surface-enhanced Raman spectroscopy (SERS) and climaxing with plasmon-mediated chemical reactions (PMCR). However, its mechanisms on various applications are tangled, severely hindering the development of related fields. Thus, it is urgent to reveal what dominates the selective routing of transferred electrons in enhanced spectroscopy and/or reaction. Herein, we elucidated direct electron transfer as the core process governing CM, with the number and lifetime of transferred electrons as key descriptors. Furthermore, we discovered that the CM for SERS and the chemical interface damping for PMCR are competitive, determined by the lifetimes of transferred electrons. Also, we emphasized the enhancement effect of the local electromagnetic field on interfacial electron transfer, revealing the overlooked synergy between CM and electromagnetic field enhancement. This work provides insights into CM and pursues the frontiers of interfacial electron transfer and related applications.