Probing Photoelectrochemical Processes in Au−CdSNanoparticle Arrays by Surface Plasmon Resonance: Application for the Detection of Acetylcholine EsteraseInhibitors
The photoelectrochemical charging of Au-nanoparticles (NP) in a Au-nanoparticle/CdS-nanoparticle array assembled on a Au-coated glass surface is followed by means of surface plasmon resonance(SPR) spectroscopy upon continuous irradiation of the sample. The charging of the Au-NPs results in theenhanced coupling between the localized surface plasmon of the Au-NP and the surface plasmon of thebulk surface, leading to a shift in the plasmon angle. The charging effect of the Au-NPs is supported byconcomitant electrochemical experiments in the dark. Analysis of the results indicates that ca. 4.2 electronsare associated with each Au-nanoparticle under steady-state irradiation. The photoelectrochemical chargingeffect of the Au-NPs in the Au−CdS NP array is employed to develop a SPR sensor for acetylcholineesterase inhibitors.