Comparison of surface-enhanced Raman scattering (SERS) effectiveness of Au nanoparticles/cicada wing substrates prepared by different methods

Two different types of Au nanoparticles (Au)/cicada wing (CW) arrays were synthesized by chemical reduction impregnation method and magnetron sputtering technique, respectively. And three-dimensional (3D) Au/CW-c (prepared by chemical reduction impregnation method) arrays and Au/CW-m (prepared by DC magnetron sputtering system) substrate were used as active substrates for SERS. The morphologies and Raman signals of the synthesized Au/CW-c and Au/CW-m substrates were characterized by field emission scanning electron microscopy (FE-SEM) and Raman system. Characterizations of the synthesized Au/CW-c and Au/CW-m substrates exhibited outstanding SERS properties. By comparing the enhanced Raman signal of Rhodamine 6G (R6G), it was found that the Au/CW-m substrate was more sensitive than Au/CW-c substrate. The results showed that the limit of detection (LOD) for R6G was as low as 10−8 M for the Au/CW-m substrate. The enhancement factors (EF) were calculated to be 5.09 × 104 for the Au/CW-c substrate and 1.12 × 106 for the Au/CW-m substrate. This phenomenon is due to the fact that the high-dense SERS “hot spots” where the collective resonance of the absorbed electrons enhances contribute to the high SERS enhancement of Au/CW-m substrate. What we have found provides a promising approach to the rapid and sensitive detection of trace of organic pollutants.