REUSABILITY OF SERS-ACTIVE SURFACES BASED ON GOLD-DECORATED HEXAGONAL ZnO NANOROD USED ZINC SHEET AS TEMPLATE

摘要

In this study, surface-enhanced Raman spectroscopic (SERS) substrates with reusability were carefully fabricated and investigated. Based on a simple and cost-effective hydrothermal process, zinc sheets were used as a base for growing zinc oxide nanorods (ZnO NRs) with hexagonal structures as templates for the SERS substrates. In the experimentation, the authors explored a variation of the physical NR structures based on precursors of zinc nitrate (Zn(NO3)(2)): hexamethylenetetramine (HMTA) at 1:1 ratio, in aqueous solution with DI water at a concentration of 2.5-20 mM. The prepared zinc oxide templates were finally decorated with gold nanoparticles (Au NPs) with the sputtering deposition for 90 s in order to promote the SERS-active surface. From physical observations, the scanning electron microscopic (SEM) results showed that the ZnO NRs exhibited an increase in size from 56.4 nm to 244.06 nm as the solution concentration was increased. Further investigations also demonstrated that the Au-decorated SERS-active samples had the gold nanoparticles covering the top of the ZnO NRs. The prepared SERS substrates were finally measured for the Raman enhancement with methylene blue (MB) as the test molecules. The results showed that the SERS substrates could detect the Raman peaks of the MB at the limit of detection of 1 x 10(-6) M. In addition, the SERS substrates were tested for reusability with the UV exposure, up to at least nine cycles. This work therefore reported the progress of the fabrications of the SERS-active materials with the reusable potentials in several SERS applications.