Electron-photon coupling in metal nanostructures has raised a new trend for active plasmonic switch devices in both fundamental understanding and technological applications. However, low sensitivity switches with an on/off ratio less than 5 have restricted applications. In this work, an electrically modulated plasmonic switch based on a surface-enhanced Raman spectroscopy (SERS) system with a single fivefold stellate polyhedral gold nanoparticle (FSPAuNP) is reported. The reversible switch of the SERS signal shows high sensitivity with an on/off ratio larger than 30. Such a high on/off ratio arises primarily from the plasmonic resonance shift of the FSPAuNP with the incident laser due to the altered free electron density on the nanoparticle under an applied electrochemical potential. This highly sensitive electro-plasmonic switch may enable further development of plasmonic devices.
Bibliographical noteFunding Information:
L.Z., Y.J., and C.L. contributed equally to this work. This work was supported by the National Natural Science Foundation of China (Project Code, 21373144), and Singapore MOE Tier2 (ARC26/15 and ARC12/12), the National Research Foundation of Singapore (CREATE Programme of Nanomaterials for Energy and Water Management). This is also a project supported by the Natural Science Foundation of Jiangsu Province (Project Code, BK20130287) and funded by the Collaborative Innovation Center of Suzhou Nano Science & Technology, and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).
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- Au nanoparticles
- electro-plasmonic switches
- fivefold stellate polyhedrons
- single nanoparticle electrodes