Tags

Type your tag names separated by a space and hit enter

Raman scattering of 4-aminobenzenethiol sandwiched between Ag nanoparticle and macroscopically smooth Au substrate: effects of size of Ag nanoparticles and the excitation wavelength.
J Chem Phys. 2011 Sep 28; 135(12):124705.JC

Abstract

A nanogap formed by a metal nanoparticle and a flat metal substrate is one kind of "hot site" for surface-enhanced Raman scattering (SERS). Accordingly, although no Raman signal is observable when 4-aminobenzenethiol (4-ABT), for instance, is self-assembled on a flat Au substrate, a distinct spectrum is obtained when Ag or Au nanoparticles are adsorbed on the pendent amine groups of 4-ABT. This is definitely due to the electromagnetic coupling between the localized surface plasmon of Ag or Au nanoparticle with the surface plasmon polariton of the planar Au substrate, allowing an intense electric field to be induced in the gap even by visible light. To appreciate the Raman scattering enhancement and also to seek the optimal condition for SERS at the nanogap, we have thoroughly examined the size effect of Ag nanoparticles, along with the excitation wavelength dependence, by assembling 4-ABT between planar Au and a variable-size Ag nanoparticle (from 20- to 80-nm in diameter). Regarding the size dependence, a higher Raman signal was observed when larger Ag nanoparticles were attached onto 4-ABT, irrespective of the excitation wavelength. Regarding the excitation wavelength, the highest Raman signal was measured at 568 nm excitation, slightly larger than that at 632.8 nm excitation. The Raman signal measured at 514.5 and 488 nm excitation was an order of magnitude weaker than that at 568 nm excitation, in agreement with the finite-difference time domain simulation. It is noteworthy that placing an Au nanoparticle on 4-ABT, instead of an Ag nanoparticle, the enhancement at the 568 nm excitation was several tens of times weaker than that at the 632.8 nm excitation, suggesting the importance of the localized surface plasmon resonance of the Ag nanoparticles for an effective coupling with the surface plasmon polariton of the planar Au substrate to induce a very intense electric field at the nanogap.

Authors+Show Affiliations

Department of Chemistry, Seoul National University, Seoul 151-742, South Korea. kwankim@snu.ac.krNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21974550

Citation

Kim, Kwan, et al. "Raman Scattering of 4-aminobenzenethiol Sandwiched Between Ag Nanoparticle and Macroscopically Smooth Au Substrate: Effects of Size of Ag Nanoparticles and the Excitation Wavelength." The Journal of Chemical Physics, vol. 135, no. 12, 2011, p. 124705.
Kim K, Choi JY, Lee HB, et al. Raman scattering of 4-aminobenzenethiol sandwiched between Ag nanoparticle and macroscopically smooth Au substrate: effects of size of Ag nanoparticles and the excitation wavelength. J Chem Phys. 2011;135(12):124705.
Kim, K., Choi, J. Y., Lee, H. B., & Shin, K. S. (2011). Raman scattering of 4-aminobenzenethiol sandwiched between Ag nanoparticle and macroscopically smooth Au substrate: effects of size of Ag nanoparticles and the excitation wavelength. The Journal of Chemical Physics, 135(12), 124705. https://doi.org/10.1063/1.3640890
Kim K, et al. Raman Scattering of 4-aminobenzenethiol Sandwiched Between Ag Nanoparticle and Macroscopically Smooth Au Substrate: Effects of Size of Ag Nanoparticles and the Excitation Wavelength. J Chem Phys. 2011 Sep 28;135(12):124705. PubMed PMID: 21974550.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Raman scattering of 4-aminobenzenethiol sandwiched between Ag nanoparticle and macroscopically smooth Au substrate: effects of size of Ag nanoparticles and the excitation wavelength. AU - Kim,Kwan, AU - Choi,Jeong-Yong, AU - Lee,Hyang Bong, AU - Shin,Kuan Soo, PY - 2011/10/7/entrez PY - 2011/10/7/pubmed PY - 2012/2/16/medline SP - 124705 EP - 124705 JF - The Journal of chemical physics JO - J Chem Phys VL - 135 IS - 12 N2 - A nanogap formed by a metal nanoparticle and a flat metal substrate is one kind of "hot site" for surface-enhanced Raman scattering (SERS). Accordingly, although no Raman signal is observable when 4-aminobenzenethiol (4-ABT), for instance, is self-assembled on a flat Au substrate, a distinct spectrum is obtained when Ag or Au nanoparticles are adsorbed on the pendent amine groups of 4-ABT. This is definitely due to the electromagnetic coupling between the localized surface plasmon of Ag or Au nanoparticle with the surface plasmon polariton of the planar Au substrate, allowing an intense electric field to be induced in the gap even by visible light. To appreciate the Raman scattering enhancement and also to seek the optimal condition for SERS at the nanogap, we have thoroughly examined the size effect of Ag nanoparticles, along with the excitation wavelength dependence, by assembling 4-ABT between planar Au and a variable-size Ag nanoparticle (from 20- to 80-nm in diameter). Regarding the size dependence, a higher Raman signal was observed when larger Ag nanoparticles were attached onto 4-ABT, irrespective of the excitation wavelength. Regarding the excitation wavelength, the highest Raman signal was measured at 568 nm excitation, slightly larger than that at 632.8 nm excitation. The Raman signal measured at 514.5 and 488 nm excitation was an order of magnitude weaker than that at 568 nm excitation, in agreement with the finite-difference time domain simulation. It is noteworthy that placing an Au nanoparticle on 4-ABT, instead of an Ag nanoparticle, the enhancement at the 568 nm excitation was several tens of times weaker than that at the 632.8 nm excitation, suggesting the importance of the localized surface plasmon resonance of the Ag nanoparticles for an effective coupling with the surface plasmon polariton of the planar Au substrate to induce a very intense electric field at the nanogap. SN - 1089-7690 UR - https://www.unboundmedicine.com/medline/citation/21974550/Raman_scattering_of_4_aminobenzenethiol_sandwiched_between_Ag_nanoparticle_and_macroscopically_smooth_Au_substrate:_effects_of_size_of_Ag_nanoparticles_and_the_excitation_wavelength_ L2 - https://doi.org/10.1063/1.3640890 DB - PRIME DP - Unbound Medicine ER -