Reusable Surface Enhanced Raman Scattering (SERS) Substrate Using Assembled Silver Nanopstructures
I-Chih Ni1*, Shien-Der Tzeng1, Jiann-Yeu Chen2, Watson Kuo2,3
1Department of Physics, National Dong Hwa University, Hualien, Taiwan
2Center of Nanoscience & Nanotechnology, National Chung Hsing University, Taichung, Taiwan
3Department of Physics, National Chung Hsing University, Taichung, Taiwan
* presenting author:倪懿池,
Assembled nanostructures consisting of silver nanoparticles (AgNP) have strong interparticle coupling effect on their surface plasmon resonance (SPR), and thus have large field enhancement between AgNPs. This could be applied to enhance the surface enhanced Raman scattering (SERS) spectrum of molecules on assembled Ag nanostructures. In our previous study [1], we had developed a novel centrifuge assembly method to fabricate molecule modified nanoparticle films with good coverage, morphology, and thickness. We also found assembled gold nanoparticle (AuNP) films have strong interparticle plasmonic coupling effect, which makes their SPR peaks red shift with the decreases of interparticle spacings. In this report, we use the centrifuge assembly method to fabricate AgNP assembled films as SERS substrate. We found the Raman intensity of Rhodamine 6G (R6G) molecules on the assembled Ag nanostructures is largely enhanced. Further, we demonstrate that ozone treatment to the SERS substrate could decrease the Raman signal of R6G analyte. The decay behavior of Raman signal decreases with the ozone treatment time could be well described by a two-ordered exponential decay. The shorter characteristic time is only about 10 second and only half of Raman signal remains after 10 s treatment. The longer characteristic time is about 5 minute. After re-adsorb R6G on the ozone treated substrate, we found their SERS intensity could be even 2 – 4 times stronger than the sample of R6G on the substrate without any ozone treatment. We will demonstrate that our SERS substrate could be reused for several times by ozone treatment. However, when the ozone treatment time is larger than 30 min, the AgNPs show serious mergence, and the SERS signal become very low. A further study is necessary to develop a better process for the reuse of SERS substrate.

[1] I-C. Ni, S.-C. Yang, C.-W. Jiang, C.-S. Luo, W. Kuo, K.-J. Lin, S.-D. Tzeng, J. Phys. Chem. C 116, 8095 (2012).
[2] S. M. Mahurin, J. John, M. J. Sepaniak, and S. Dai, Applied Spectroscopy 65, 417 (2011).

Keywords: SERS, Reusable SERS Substrate, Assembled Silver Nanopstructures