TY - JOUR
T1 - Adsorption characteristics of 4,4′-bipyridine molecules on gold nanosphere films studied by surface-enhanced Raman scattering
AU - Suzuki, Mototsugu
AU - Niidome, Yasuro
AU - Yamada, Sunao
N1 - Funding Information:
This study was supported by Industrial Technology Research Grant Program in '03 from New Energy and Industrial Technology Development Organization (NEDO) of Japan, and by Grant-in-Aids for the 21st Century COE Program, “Functional Innovation of Molecular Informatics”, and for Scientific Research on Priority Areas (417) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of the Japanese Government. We thank Prof. N. Kimizuka of our department for SEM measurements, and Mr. Y. Yasukochi of YUJI KIKAKU Ltd. for the setup of the Raman spectroscopic system.
PY - 2006/2/21
Y1 - 2006/2/21
N2 - We have measured and compared the surface-enhanced Raman scattering (SERS) spectra of 4,4′-bipyridine (bpy) molecules deposited (adsorbed) on the films of gold nanospheres (NSs, mean diameter 35 ± 5 nm), as prepared by the salting-out method using NaClO4 and NaOH. The bpy-deposited (adsorbed) films were prepared by casting an aliquot of the bpy-ethanol solutions in different concentrations (less and above the monolayer converge on the gold surface), or on immersion of the NS films into the concentrated bpy solution. The enhancement of the SERS spectra of bpy was larger for the NS film prepared from NaClO4 than that from NaOH. But, the SERS intensity was independent of the concentration of the bpy solution. The changes in the intensities and the shapes of the SERS spectra were distinctly observed on immersion of the bpy-deposited (adsorbed) NS films into pure ethanol, and these spectral changes were prominent for the NS film prepared from NaClO4. This must be attributed to considerably coalesced structures of the NS film prepared from NaClO4. From the comparison of the intensity changes before and after immersion into ethanol, it is suggested that the vertical orientation of the bpy molecules adsorbed on the NS films changes into the flat orientation with respect to the surface of the gold nanoparticles at the solid-liquid interface, on immersion of the film into pure ethanol.
AB - We have measured and compared the surface-enhanced Raman scattering (SERS) spectra of 4,4′-bipyridine (bpy) molecules deposited (adsorbed) on the films of gold nanospheres (NSs, mean diameter 35 ± 5 nm), as prepared by the salting-out method using NaClO4 and NaOH. The bpy-deposited (adsorbed) films were prepared by casting an aliquot of the bpy-ethanol solutions in different concentrations (less and above the monolayer converge on the gold surface), or on immersion of the NS films into the concentrated bpy solution. The enhancement of the SERS spectra of bpy was larger for the NS film prepared from NaClO4 than that from NaOH. But, the SERS intensity was independent of the concentration of the bpy solution. The changes in the intensities and the shapes of the SERS spectra were distinctly observed on immersion of the bpy-deposited (adsorbed) NS films into pure ethanol, and these spectral changes were prominent for the NS film prepared from NaClO4. This must be attributed to considerably coalesced structures of the NS film prepared from NaClO4. From the comparison of the intensity changes before and after immersion into ethanol, it is suggested that the vertical orientation of the bpy molecules adsorbed on the NS films changes into the flat orientation with respect to the surface of the gold nanoparticles at the solid-liquid interface, on immersion of the film into pure ethanol.
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U2 - 10.1016/j.tsf.2005.09.114
DO - 10.1016/j.tsf.2005.09.114
M3 - Article
AN - SCOPUS:28044465186
SN - 0040-6090
VL - 496
SP - 740
EP - 747
JO - Thin Solid Films
JF - Thin Solid Films
IS - 2
ER -