Plasmonic metal surfaces can fire energetic electrons into adjacent molecules, triggering chemical reactions with light rather than heat. Most research on surface plasmons—the collective electron oscillations that trap light at metal surfaces—has focused on their ability to concentrate electromagnetic fields. This has enabled biosensors, chemical detectors, and enhanced imaging. But the electrons themselves, which carry significant energy as they oscillate, have been largely ignored. This project will investigate how those "hot electrons" transfer from the metal into nearby materials, and whether they can drive physical and chemical processes independently of the intense electric fields. If successful, the work could enable ultrafast, light-switchable chemical reactions at the nanoscale—catalysis controlled by a flash of light rather than a furnace. It might also allow optical control of electronic processes in semiconductor devices, and nanoscale temperature regulation. The research is fundamental science: it aims to understand a previously overlooked mechanism in plasmonics. Past fundamental work on plasmon-enhanced effects has already yielded commercial biosensors and chemical detectors; this programme could open similarly unexpected technological pathways.
View original technical description
The coherent oscillations of mobile charge carriers near the surface of good conductors-surface plasmons- have amazing properties. Light can be coupled to these surface plasmons and trapped by them near the interface between a metal and an adjacent material. This leads to the nanoscale confinement of light, impossible by any other means, and a related electromagnetic field enhancement. The associated effects and applications include high sensitivity to the refractive index of surroundings used in biosensors, enhancement of Raman scattering near the metal surfaces used in chemical sensing and detection, enhanced nonlinear optical effects, localised light sources for imaging, and many others. At the same time the influence of the electrons which participate in the formation of surface plasmons on the surroundings of the metal nanostructures is virtually unexplored. Microscopic electron dynamic effects associated with surface plasmons are capable of significantly influencing physical and chemical processes near the metal surface, not (only) as a result of the high electric fields, but also from the transfer of energetic electrons to the adjacent molecules or materials. We propose to develop a comprehensive research programme in order to understand the physics and harness applications associated with such electronic processes, induced by plasmonic excitations, in designer nanostructures. This will open up new paradigms in ultrafast control over nanoscale chemical reactions switchable with light, optically controlled catalysis, optical and electric processes in semiconductor devices induced by plasmonic hot-electrons, as well as nanoscale and ultrafast temperature control, and many other technologies of tomorrow.
Plain English summaries and category classifications on this site are generated by AI and may not perfectly reflect the original research.
Is something wrong? Let us know