In-situ deposition of silver nanoparticles on silver nanoflowers for ultrasensitive and simultaneous SERS detection of organic pollutants

Abstract

Recently, a great deal of research has been stepped forward to implement real-time detection of multiple targets using surface-enhanced Raman spectroscopy (SERS). Herein, a novel incorporation of silver nanoparticles (AgNPs) on silver nanoflowers (AgNFs) via the in-situ process offers high SERS enhancement by its unique plasmonic resonance. The electromagnetic mechanism of AgNFs incorporated with AgNPs generates numerous hotspots from abundant nanogaps on nanoflowers and between nanoparticles for ultrasensitive detection of probe molecules. The increment in the SERS signal is demonstrated by depositing the probe molecules, rhodamine 6G (R6G) and Congo Red (CR), on the proposed nanostructure. The proposed AgNF@AgNP nanostructure provides stronger SERS activity than the individual AgNPs and Ag NFs, and possesses superior detection ability towards R6G (10−14 M) and CR (10−9 M) with excellent uniformity (<10.27%) and analytical enhancement factor (AEF) (1012 for R6G and 107 for CR). Moreover, the simultaneous SERS detection of R6G and CR has been demonstrated with trace-level detection of CR at 10−8 M and R6G at 10−13 M. The AgNF@AgNP nanostructure with dense hotspots offers remarkable SERS activity, and becomes as a potential tool to analyze organic molecules from environment for real-world applications.