Rectangular Silver Nanorods: Controlled Preparation, Liquid−Liquid Interface Assembly, and Application in Surface-Enhanced Raman Scattering

Abstract

In this paper, we for the first time report a polyol method for large-scale synthesis of rectangular silver nanorods in the presence of directing agent and seeds. This method has some clear advantages including simplicity, high quality, and ease of scaleup. Silver nanowires or silver nanorods with a submicrometer diameter could also be facilely prepared when the reaction parameters are slightly changed. Furthermore, a liquid−liquid assembly strategy has been employed to construct uniform rectangular silver nanorod arrays on a solid substrate which could be used as surface-enhanced Raman scattering (SERS) substrates with high SERS activity, stability, and reproducibility. It is found that the SERS spectra obtained from the probe molecules with the different concentrations show different SERS intensities. As the concentration of 4-aminothiophenol (4-ATP) or rhodamine 6G (R6G) increases, the SERS intensities progressively increase. The enhancement factor for 4-ATP and R6G should be as large as 5.06 × 104 or much larger than the value of 5.06 × 108, respectively. Most importantly, the SERS spectra of R6G on the assembling film are well reproducible at different sites on a substrate, with a standard deviation of <20%. Our results will open new possibilities for applying SERS to detect different analytical species due to the good reproducibility of the present SERS substrate.