pH-Triggered SERS via Modulated Plasmonic Coupling in Individual Bimetallic Nanocobs
AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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In this Communication, we demonstrate the pH-triggered SPR and SERS properties of silver nanowires functionalized with gold nanoparticles in both solution and dry states. In contrast with previous examples of such bimetallic nanocobs, we utilize here a responsive polyacrylic acid PAA nanocoating that acts as a linker between the nanoparticles and nanowire. The pH-responsive nature of the PAA nanocoating, which is sensitive to the environmental pH, is employed to vary the separation distance between the gold nanoparticles and the silver nanowire and thus control plasmon coupling. Moreover, placing nanoparticles inside a polymer-gel layer in close proximity to the nanowire surface effectively prevents any potential aggregation of nanoparticles under variable environmental conditions, in contrast with regular nanoparticle solutions, which easily precipitate with changing conditions.
- Properties of Metals and Alloys