(50g) Electrochemical Deposition of Pt Nanoparticles on Au-Coated DVD-R Gratings for Sensitive Surface Plasmon Resonance Detection
Successive deposition of additional catalyst layers or nanoparticles on plasmonic metal surfaces is critical for utilizing surface plasmon resonance (SPR) as a sensitive detection technique for in-situ heterogeneous catalysis study under realistic conditions. Here we demonstrated the electrochemical deposition of Pt nanoparticles on Au-coated surface gratings of conventional DVD-R discs. Before Pt electrodeposition, the Au grating showed a SPR sensitivity of 974 nm per refractive index unit (nm/RIU) and SPR figure of merit (FOM) of 69 in normal-incidence reflection measurements. The SPR sensitivity was slightly increased to 976 nm/RIU after 1 potential scan and it was then decreased after further Pt deposition. The SPR FOM was decreased with increased amount of Pt deposition due to the gradually increased full width at half maximum (FWHM) of the reflection peaks. But the sample still showed a high sensitivity of 957 nm/RIU and a FOM of 56 after 3 potential scans. The tunability in optical properties (e.g., SPR sensitivity, FOM, FWHM, and peak amplitude) of the plasmonic surface gratings was mainly caused by the modification of the DVD-R structure of the Au surface by Pt electrodeposition. These influences were examined by X-ray diffraction, atomic force microscopy (AFM) images, surface roughness analysis, and finite-difference time-domain (FDTD) simulations.