Electrochemical Synthesis of Fractal Nanostructures for Efficient Surface-Enhanced Raman Spectroscopy

Fractal nanostructures have sharp tips and edges, and the gap between each trunk and branch is narrow. The structure is ideal for generating high-density plasmonic "hot spots" to achieve a high-intensity local electromagnetic (EM) field, which is beneficial for improving the substrate Raman activity. In this paper, an electrochemical method is used to prepare a silver fractal nanostructure substrate. A single layer of graphene is transferred to the surface of the silver fractal structure substrate by a wet chemical transfer method to prepare a graphene/metal (G/silver fractal) nanostructure composite substrate. Experimental observations show that G/silver fractal nanostructures exhibit higher Raman activity than that of pure silver fractal nanostructures. Numerical simulation calculation also verifies the accuracy of the experiment. In addition, the diversity of substrate detection is analyzed, and the experimental results show that the substrate can detect Rh6G and CV probe molecules simultaneously, which provides an experimental basis for investigating multichannel Raman spectroscopy sensing substrates. Therefore, the fabricated G/silver fractal nanostructure substrate provides substrate support and an experimental basis for Raman spectroscopy detection in several fields, including actual environment detection and biomedical vibration.