Dual-Responsive Plasmonic Behavior of Gold Nanorods@PANI Core/Shell Nanostructures for Real-Time Control

Plasmonic nanoparticles have attracted great attention due to their unique localized surface plasmon resonance (LSPR) that can be utilized in various applications including solar cells, photocatalysis, and sensors. For target applications, specific LSPR properties can be achieved by controlling plasmonic particle’s shape, composition, and size. However, for a given structure, it is generally challenging to control their plasmonic properties in a real time. In the present research, we demonstrate dual-responsive gold nanorod (AuNR)/polyaniline (PANI) core-shell nanostructures where the LSPR of AuNR cores can reversibly be controlled by changing electrochemical potential as well as environmental pH. The largest LSPR shift of the AuNR cores is achieved when environmental pH is changed. A significant plasmonic shift of 107 nm is obtained with only 8 nm thick PANI shell due to the large refractive index change of PANI shells and the high LSPR sensitivity of AuNRs. Furthermore, the AuNR@PANI core/shell showed very stable and reversible LSPR dual-responsive properties during the cycling test without significant degradation.