Synthesis of single-crystal silver slices with predominant (1 1 1) facet and their SERS effect

In this article, single-crystal silver slices with predominant (1 1 1) facet were synthesized at room temperature with chitosan by a facile, one-pot, and totally green method. XRD, UV–visible and infrared spectroscopy have been employed for identifying chitosan-protected silver nanoparticles (NPs), while SEM, TEM were used to confirm silver NPs orientation along the (1 1 1) direction to form various shapes such as hexagon, trapezium, triangle and so on. The results showed that chitosan, a novel environmentally benign and excellently biocompatible material, serves not only as a reducing agent but also as a stabilizer for the growth of anisotropic silver NPs. The single-crystal silver slices with major facet of (1 1 1) can be used as a surface-enhanced Raman scattering (SERS) substrate, and crystal violet (CV) as a Raman probe to evaluate its enhancement ability. It was found that the enhancement ability of the silver slices was remarkable.