Surface-enhanced Raman scattering of a series of n-hydroxybenzoic acids (n = P, M and O) on the silver nano-particles.
Surface-enhanced Raman scattering (SERS) spectra of a series of n-hydroxybenzoic acids (n-HBA, n = P, M and O) adsorbed on the silver nano-particles were studied, respectively, in the silver colloidal solution and on the dried silver-coated filter paper. On the same substrate, the different molecules' SERS spectra were different, while on the different substrates the same molecules' SERS spectra were also different. Significant changes were found in the SERS spectra of PHBA molecules adsorbed on the two substrates, and the changes found in MHBA's spectra on two substrates were next to PHBA's, while almost no changes were found in the spectra of OHBA molecules. Moreover, it was found, on the filter paper, that the SERS spectra of the same molecules would change with the coverage density of the silver nano-particles. The analyses showed that the origins of these changes were the different adsorption behavior of molecules adsorbed on the silver nano-particles. Because in these three molecules the relative positions of the carboxyls and hydroxyls on the benzenes are different, the adsorption behaviors of these three molecules adsorbed on the silver surfaces are also different. The experimental results suggest that the surface characteristic of the substrate and the surface configuration of the adsorbate could exert a great influence on the adsorption behavior of the adsorbates on the substrates.
Wu
Di
D
Beijing Key Lab of Nano-Photonics and Nano-Structure (NPNS), Department of Physics, Capital Normal University, Beijing 100037, PR China.
Fang
Yan
Y
D000327:Adsorption; D003102:Colloids; D062385:Hydroxybenzoates / Q000737:chemistry*; D015394:Molecular Structure; D049329:Nanostructures; D010209:Paper; D012834:Silver; D013059:Spectrum Analysis, Raman
D003102:Colloids; D062385:Hydroxybenzoates; D012834:Silver