Open Access Nano Express

Fabrication and evolution of multilayer silver nanofilms for surface-enhanced Raman scattering sensing of arsenate

Jumin Hao1, Mei-Juan Han1, Zhonghou Xu1, Jinwei Li2 and Xiaoguang Meng1*

Author Affiliations

1 Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, USA

2 Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, USA

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Nanoscale Research Letters 2011, 6:263  doi:10.1186/1556-276X-6-263

Published: 28 March 2011

Abstract

Surface-enhanced Raman scattering (SERS) has recently been investigated extensively for chemical and biomolecular sensing. Multilayer silver (Ag) nanofilms deposited on glass slides by a simple electroless deposition process have been fabricated as active substrates (Ag/GL substrates) for arsenate SERS sensing. The nanostructures and layer characteristics of the multilayer Ag films could be tuned by varying the concentrations of reactants (AgNO3/BuNH2) and reaction time. A Ag nanoparticles (AgNPs) double-layer was formed by directly reducing Ag+ ions on the glass surfaces, while a top layer (3rd-layer) of Ag dendrites was deposited on the double-layer by self-assembling AgNPs or AgNPs aggregates which had already formed in the suspension. The SERS spectra of arsenate showed that characteristic SERS bands of arsenate appear at approximately 780 and 420 cm-1, and the former possesses higher SERS intensity. By comparing the peak heights of the approximately 780 cm-1 band of the SERS spectra, the optimal Ag/GL substrate has been obtained for the most sensitive SERS sensing of arsenate. Using this optimal substrate, the limit of detection (LOD) of arsenate was determined to be approximately 5 μg·l-1.