Refractive index sensitivity of Au nanostructures in solution and on the substrate
Hemant Hegde, Santhosh Chidangil, Rajeev K. Sinha
Abstract
Abstract In this work, we present the synthesis and surface immobilization of Au nanostars, Au nanocubes and Au nanorods for localized surface plasmon resonance (LSPR)-based refractometric sensing applications. Au nanostructures exhibiting LSPR peak positions in 500–900 nm spectral range were prepared by seed-mediated synthesis method. The refractive index (RI) sensitivity of all these nanostructures in the colloidal solution were measured and the sample exhibiting highest sensitivity in each category were immobilized on the glass substrate. The surface immobilized nanostructures were investigated for RI sensing. Au nanostars having LSPR peak position at 767 nm exhibited highest RI sensitivity of 484 nm/RIU in solution and 318 nm/RIU on the substrate. This study gives an outline for selecting the Au nanostructures for developing plasmonic sensing platforms.