Preparation and Characterization of Nanoporous Gold Film Based Surface Plasmon Resonance Sensor
(2.University of Chinese Academy of Sciences, Beijing, China 100049)
【Abstract】Au-Ag alloy films of around 60 nm thickness are deposited on the slab glass substrate by radio frequency sputtering technique. Large-area uniform nanoporous gold films (NPGF) with strong adhesion are then fabricated by chemical dealloying of the alloy film at room temperature. The resonance spectrum in the visible-near infrared region for the NPGF exposed to air is obtained by a self-built broadband spectral surface plasmon resonance (SPR) detection platform. The Fresnel formula and Bruggeman dielectric constant approximation equation are used to fit the experimental results, resulting in the porosity of NPGF to be about 0.38. The response characteristics of the NPGF-SPR sensor to Pb2+ ions and melamine molecules adsorbed from the individual aqueous solutions with different concentrations are investigated. The experimental results show that the NPGF-SPR sensor can make obvious responses to both Pb2+ ions and melamine molecules in the aqueous solution with 1 nmol·L−1 concentration. The comparison experiment shows that the NPGF-SPR sensor is much more sensitive than the conventional SPR sensor with a dense gold layer.
【Keywords】 sensors; nanoporous gold film; surface plasmon resonance; porosity; high sensitivity;
(Translated by LIN LY)
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