Plasmonic sensing of Cu2+ via shell-etching of Au@Ag nanorods

Bimetallic nanocrystals are widely used in plasmonic sensors owing to the wide-range tunable surface plasmon resonance peak. Here, a [email protected] core-shell nanorod is demonstrated as a plasmonic sensor to realize Cu2+ detection via nanorod shell etching. The Cu2+ concentration can be easily detected by observing the color of the solution containing [email protected] nanorods. A relatively low detection limit of 1.3 μM is obtained by monitoring the extinction spectra. The [email protected] bimetallic plasmonic sensor exhibits a high sensitivity for Cu2+ detection and also excludes interference from other prevalent ions in the solution. This work exhibits an excellent example of the application of shell-etching for heavy metal ion detection, which provides a potential application in biology and environmental monitoring fields.