Synthesis of ultrathin silver shell on gold core for reducing substrate effect of LSPR sensor

The refractive index sensitivity of gold@silver core-shell nanoparticles on indium tin oxide glass was investigated. The thin silver shell was electrodeposited on gold surface by controlling the applied potential and electrodeposition cycles. The refractive index sensitivity at gold@silver core-shell nanoparticles with ultrathin silver shell (~ 0.7 nm) to bulk refractive index was enhanced 76% than that of the Au nanoparticles (Au core) deposited on ITO substrate. This core-shell platform was also applied to detection of biomolecular interactions using the streptavidin-biotin assay. The strategy would reduce greatly the substrate effect of plasmonic sensors.

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► Thin silver shell was electrodeposited on surface of gold nanoparticles.
► This core-shell nanoparticles were supported by substrate as a sensor platform.
► The refractive index sensitivity was enhanced greatly at ultrathin Ag shell platform.
► This platform was also applied to detection of biomolecular interaction.