title: Electrochemistry on a localized surface plasmon resonance sensor.
abstract: The optical signal of a localized surface plasmon resonance (LSPR)-based sensor combined with electrochemistry was investigated. Gold nanoparticles were immobilized on an indium tin oxide (ITO) substrate, which functioned as working electrode. Using cyclic voltammetry synchronized with LSPR sensing, surface reactions on gold were detected both electrically and optically. In the capacitive charging regime, optical signals linear to the applied potential were detected. Gold was found to be dissolved above the oxidation potential and partially redeposited during the reduction, which changed size and conformation of the gold nanoparticles. In kinetic measurements, slower potential establishment was observed at lower salt concentrations. Simulations by multiple multipole program (MMP) suggested the formation of a lossy layer by combination of charge depletion of gold and negative ion adsorption even below the reaction potential. We consider the results presented here of importance for any future sensors based on combined plasmonics and electrochemistry.
authors.affiliation: Laboratory of Biosensors and Bioelectronics, Department of Information Technology and Electrical Engineering, ETH Zürich, Zürich, Switzerland.
authors.forename: Takumi
authors.initials: T
authors.lastname: Sannomiya
authors.forename: Harald
authors.initials: H
authors.lastname: Dermutz
authors.forename: Christian
authors.initials: C
authors.lastname: Hafner
authors.forename: Janos
authors.initials: J
authors.lastname: Vörös
authors.forename: Andreas B
authors.initials: AB
authors.lastname: Dahlin
mesh_terms: D004563:Electrochemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D010316:Particle Size; D020349:Surface Plasmon Resonance / Q000295:instrumentation / Q000379:methods*; D013499:Surface Properties; D017971:Tin Compounds / Q000737:chemistry
chemical_list: D017971:Tin Compounds; C109984:indium tin oxide; D006046:Gold