Influence of the microstructure of several substrates on the SERS effect of p-hyroxybenzoic absorbed on Ag nanoparticles

Quantitative and slow-speed filter papers, microporous filter films, thin-layer chromatoplate aluminum sheets (TLCAS) and silica gel glass sheets (SGGS) coated with Ag nanoparticles were used as SERS-active substrates, on which high-quality surface-enhanced Raman scattering (SERS) spectra of p-hydroxybenzoic acid (PHBA) were obtained with some fine distinction. Scanning electron micrograph (SEM) images analysis is shown that the microstructures of four substrates are different, which affects Ag nanoparticles adsorbed on the substrate surface. The impressive contrast of experimental results and calculated Raman spectra with DFT-B3PW91 is illuminated that there are mainly two adsorption behavior of PHBA on the surface of four Ag-coated substrates. Based on these results, a rather essential influence to the mechanism of SERS effect is given.