Optical Fiber Optrodes with Silver-Coated Gold Nano-Cavity Ordered Arrays (Coa) for Highly Sensitive Surface Enhanced Raman Spectrum

Abstract

In this paper, we propose a new strategy for fabricating surface enhanced Raman scattering (SERS) optical fiber optrodes with ordered gold nanocavities modified by Ag nanoparticles (AgNPs) on the fiber tip. Such nanocavity ordered arrays (COA) structure have strong light trapping ability and improve the utilization of light by multiple reflection of light. Besides, the COA have lager specific surface area which can provide a large amount of SERS “hot spots”, and also enable absorb more probe molecules. Furthermore, secondary deposition silver can result in a strong coupling between gold nanocavirties and AgNPs. Consequently, the nanocavity arrays can be further enhanced local surface plasmon resonance (LSPR) effect to improve sensitivity of SERS optrodes. We have studied such nanocavity SERS optrode for in situ detection of 4-Aminothiophenol (4-ATP) with detection limits of 10-10 M. The highly sensitive, good reproducible and high stable SERS optrode shows excellent performance in liquid-phase in-situ and remote SERS detection, is promising for water environmental monitoring applications. This paper provides a simple and low cost technology suitable for large-scale fabricating of highly sensitive optical fiber SERS optrode.

Keywords: nano-cavity ordered arrays, optrodes, highly sensitive, in-situ, remote sensing