A highly-ordered and uniform sunflower-like dendritic silver nanocomplex array as reproducible SERS substrate

Abstract

Surface-enhanced Raman scattering (SERS) is widely recognized as a powerful analytical tool. However, its application has been limited by the lack of reliable and reproducible metal-particle substrates. In this work, a silver (Ag) nanocomplex array SERS substrate with highly-ordered and uniform sunflower-like structure was fabricated by integrating deep-ultraviolet lithography and electrodeposition methods. The as-prepared nanocomplex array, consisting of a thin circular Ag nanoparticle layer in the centre and dendritic Ag nanostructures at the flange, exhibited a substantial enhancement in Raman signals and good reproducibility for SERS measurement of 4-aminothiophenol. The dendritic nanostructures were formed as a result of the edge effect and diffusion-limited aggregation. The morphology and Raman signal enhancement of the substrate were governed by electrodeposition parameters such as electrodeposition time, deposition potential and citric acid concentration. This fabrication approach is facile, cost-effective, highly reproducible and easily controllable, offering a great opportunity for large-scale production of substrate and practical application of SERS.