Open Access Nano Express

Self-assembly of large-scale gold nanoparticle arrays and their application in SERS

Sheng-Qing Zhu123, Tong Zhang123*, Xin-Li Guo4 and Xiao-Yang Zhang123

Author Affiliations

1 School of Electronic Science and Engineering, Southeast University, Nanjing 210096, People’s Republic of China

2 Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology, Ministry of Education, Nanjing 210096, People’s Republic of China

3 Suzhou Key Laboratory of Metal Nano-Optoelectronic Technology, Suzhou Research Institute of Southeast University, Suzhou 215123, People’s Republic of China

4 School of Materials Science and Engineering, Southeast University, Nanjing 211189, People’s Republic of China

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Nanoscale Research Letters 2014, 9:114  doi:10.1186/1556-276X-9-114

Published: 13 March 2014

Abstract

Surface-enhanced Raman scattering is an effective analytical method that has been intensively applied in the field of identification of organic molecules from Raman spectra at very low concentrations. The Raman signal enhancement that makes this method attractive is usually ascribed to the noble metal nanoparticle (NMNP) arrays which can extremely amplify the electromagnetic field near NMNP surface when localized surface plasmon resonance (LSPR) mode is excited. In this work, we report a simple, facile, and room-temperature method to fabricate large-scale, uniform gold nanoparticle (GNP) arrays on ITO/glass as SERS substrates using a promoted self-assembly deposition technique. The results show that the deposition density of GNPs on ITO/glass surface increases with prolonging deposition time, and nanochain-like aggregates appear for a relatively longer deposition time. It is also shown that these films with relatively higher deposition density have tremendous potential for wideband absorption in the visible range and exhibit two LSPR peaks in the extinction spectra because the electrons simultaneously oscillate along the nanochain at the transverse and the longitudinal directions. The SERS enhancement activity of these GNP arrays was determined using 10-6 M Rhodamine 6G as the Raman probe molecules. A SERS enhancement factor as large as approximately 6.76 × 106 can be obtained at 1,363 cm-1 Raman shift for the highest deposition density film due to the strong plasmon coupling effect between neighboring particles.

Keywords:
Self-assembly; Gold nanoparticle; SERS; Plasmonics; Localized surface plasmon resonance