Plasmonic Hot Carriers Imaging: Promise and Outlook

Extraordinary light matter interaction on the surface of metallic nanostructures can excite surface plasmons (SPs), followed by generation of charge carriers with high energy, that is, hot electrons and holes, via nonradiative decay. Such plasmonic hot carriers are potentially useful for photocatalysis, electrocatalysis, photovoltaics, optoelectronics, and theragnosis since hot carrier transfer to the desired substrate can accelerate specific redox reactions or facilitate electrical benefits on devices. In this regard, there is a growing interest in the detection and visualization of hot carriers at the location where plasmonic hot carriers are practically generated and transferred by means of conventional or newly developed procedures, as summarized in Table 1 of the main paper. Although direct imaging of plasmonic hot carriers or pathways are still challenging due to ultrafast dynamics of plasmonic hot carriers, state-of-the-art microscopic approaches have successfully demonstrated the mapping of the localized surface plasmons (LSPs) and plasmonic hot carriers. In addition, more accessible and facile approaches by mediation of chemical probes have also been emerged in recent years for the same purpose. The aim of this Perspective is to provide an idea of how spatial information on the generation and transfer of plasmonic hot carriers can be associated with the future design of plasmonic nanomaterials or nanocomposites to increase the output of hot carrier-driven processes. Along with a comprehensive overview of surface plasmon decay into plasmonic hot carriers and the necessity of plasmonic hot carrier imaging, we will highlight some recent advances in plasmonic hot carrier imaging techniques and provide remarks on future prospects of these techniques.