Issue 19, 2018

Electrochemical impedance spectroscopy of single Au nanorods

Abstract

We propose monochromatic dark-field imaging microscopy (DFM) to measure the non-faradaic electrochemical impedance spectroscopy (EIS) of single Au nanorods (AuNRs). DFM was utilized to monitor the plasmonic scattering of monochromatic incident light by surface-immobilized individual AuNRs. When modulating the surface potential at a certain frequency, non-faradaic charging and discharging of AuNRs altered their electron density, leading to periodical fluctuations in the scattering intensity. Analysis of the amplitude and phase of the optical intensity fluctuation as a function of modulation frequency resulted in the EIS of single AuNRs. High-frequency (>100 Hz) modulation allowed us to differentiate the intrinsic charging effect from other contributions such as the periodic migration and accumulation of counterions in the surrounding medium, because the latter occurred at a longer timescale. As a result, single nanoparticle EIS led to the surface capacitance of single AuNRs being closer to the theoretical value. Since interfacial capacitance has been proven sensitive to molecular interactions, the present work also offers a new platform for single nanoparticle sensing by measuring the single nanoparticle capacitance.

Graphical abstract: Electrochemical impedance spectroscopy of single Au nanorods

Supplementary files

Article information

Article type
Edge Article
Submitted
01 3 2018
Accepted
02 4 2018
First published
02 4 2018
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY-NC license

Chem. Sci., 2018,9, 4424-4429

Electrochemical impedance spectroscopy of single Au nanorods

T. Liu, M. Li, Y. Wang, Y. Fang and W. Wang, Chem. Sci., 2018, 9, 4424 DOI: 10.1039/C8SC00983J

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