Aggregation of silver particles trapped at an air-water interface for preparing new SERS active substrates

作者:Hu JW; Zhao B*; Xu WQ; Fan YG; Li BF; Ozaki Y
来源:Journal of Physical Chemistry B, 2002, 106(25): 6500-6506.
DOI:10.1021/jp0143286

摘要

In this paper, we propose a novel technique for the fabrication of active substrates of surface-enhanced Raman scattering (SERS). It was found that the silver particles themselves and the analyte-covered silver particles can be trapped at the air-water interface. In the presence of electrolyte, for example, KCl that is generally used to activate silver colloids for additional SERS enhancement, the trapped silver particles and clusters can attract each other spontaneously to form two-dimensional silver particle films. By this technique, the prerequisite aggregation of silver colloids for the SERS process is provided. At the same time, because the aggregation occurs only at the interface, problems of irreversible aggregation and instability of silver colloids can largely be overcome. The SERS enhancement ability of these silver particle films is larger by 1-2 orders than that of usual active substrates such as silver colloids and silver mirror. Their strong enhancement ability may arise from the unique two-dimensional structure itself.