Surface-enhanced Raman scattering (SERS) studies on silver nanorod substrates

We report the development of a novel SERS substrate prepared by the growth of silver nanorods directly on the surface of glass without using any linker molecule. Silver nanorods were prepared according to seed-mediated growth approach using cetyl-trimethyl ammonium bromide (CTAB). Nanorod preparation conditions were first optimized in solution phase and the plasmon absorption of the formed nanocrystals were monitored by UV–vis spectrometry. The most significant red shift in the longitudinal plasmon resonance absorption of silver nanostructures was maximized in order to achieve the highest electromagnetic enhancement in Raman measurements. The images of the formed nanorods were recorded using field emission scanning electron microscopy (FE-SEM). These optimized conditions were adopted for the growth of nanorods on the surface of the glass substrate. Sol–gel-coated glass slides were used in order to increase the porosity on the surface for an effective seeding process. The SERS performances of the nanorod covered surfaces were evaluated by the signals of crystal violet (CV), brilliant cresyl blue (BCB) and benzoic acid (BA). Some modifications, for the enhancement of the SERS signals, such as the increase in the AgNO3 concentration in the growth solution and the addition of hydrocarbons to the growth solution were investigated. The high quality of the spectra obtained for the model compounds demonstrated the efficiency of the prepared substrate for the SERS enhancement and its potential as a SERS detection probe for chemical and biological analysis.