Characterization of localized surface plasmon resonance transducers produced from Au₂₅ nanoparticle multilayers

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• 作者：Paul Vaccarello^a ; Linh Tran^a ; Julia Meinen^b ; Chuhee Kwon^b ; Yohannes Abate^b ; Young-Seok Shon^a ; ^{ys.shon@csulb.edu} ; ^{yshon@csulb.edu}
• 关键词：s-SNOM ; scattering-type scanning near-field optical microscopy ; LSPR ; localized surface plasmon resonance ; SP ; surface Plasmon ; ConA ; Concanavalin A ; DCC ; N ; N&prime ; -dicyclohexylcarbodiimide ; DMAP ; 4-dimehtylaminopyridine ; MPTS ; 3-mercaptopropyl trimethox
• 刊名：Colloids and Surfaces A ; Physicochemical and Engineering Aspects
• 出版年：2012
• 期刊代码：22_09277757
• 类别：ch
• 出版时间：20 May, 2012
• 卷：402
• 期：Complete
• 页码：146-151
• 文件大小：938 K

摘要

This article reports the preparation of gold plasmonic transducers using a nanoparticle self-assembly/heating method and the characterization of the films using scattering-type scanning near-field optical microscopy (s-SNOM). Nanoparticle-polymer multilayer films were prepared by the layer-by-layer assembly on glass slides by alternating exposures to monodisperse Au₂₅ nanoparticles and ionic polymer linkers. Thermal evaporation of organic matters from the nanoparticle-polymer multilayer films at 600 掳C allowed the nanoparticles to coalescence and form nanostructured films. Characterization of the nanostructured films generated from Au₂₅ nanoparticles using atomic force microscopy (AFM) showed that the films have rounded, small, island-like morphologies (d: 30-50 nm) with a pit in the center of many islands. However, further characterizations with s-SNOM revealed that the produced nanoislands contain a single gold cluster in a pit surrounded by donut-shaped dielectric species. Formation of such a structure is thought to be resulted from the embedding of gold clusters under the reorganized polysiloxane binder coatings and glass surfaces during heat treatment of the Au₂₅ nanoparticle multilayer films. The nanostructured films displayed strong surface plasmon resonance bands in UV-vis spectra with a peak absorbance occurring at 鈭?45-550 nm. The optical sensing capability of the films was examined using d-glucose-functionalized gold island films with the interaction of Concanavalin A (ConA). The result showed that the adsorption of ConA on island films causes a large change in the LSPR band intensity.