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Itoh T, Yamamoto YS. Electromagnetic enhancement spectra of one-dimensional plasmonic hotspots along silver nanowire dimer derived via surface-enhanced fluorescence. J Chem Phys 2024; 160:024703. [PMID: 38189611 DOI: 10.1063/5.0179985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 12/19/2023] [Indexed: 01/09/2024] Open
Abstract
We developed a spectroscopic method for directly obtaining the spectra of electromagnetic (EM) enhancement of plasmonic hotspots (HSs). The method was applied to one-dimensional (1D) HSs generated between silver nanowire (NW) dimers. The EM enhancement spectra were derived by dividing the spectra of surface-enhanced fluorescence (SEF) from single NW dimers with SEF obtained from large nanoparticle aggregates, where aggregate-by-aggregate variations in the SEF spectra were averaged out. Some NW dimers were found to exhibit EM enhancement spectra that deviated from the plasmon resonance Rayleigh scattering spectra, indicating that their EM enhancement was not generated by superradiant plasmons. These experimental results were examined by numerical calculation based on the EM mechanism by varying the morphology of NW dimers. The calculations reproduced the spectral deviations as the NW diameter dependence of EM enhancement. Phase analysis of the enhanced EM near-fields along the 1D HSs revealed that the dipole-quadrupole coupled plasmon, which is a subradiant mode, mainly generates EM enhancement for dimers with NW diameters larger than ∼80 nm, which was consistent with scanning electron microscopic measurements.
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Affiliation(s)
- Tamitake Itoh
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu, Kagawa 761-0395, Japan
| | - Yuko S Yamamoto
- School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), Nomi, Ishikawa 923-1292, Japan
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Itoh T, Yamamoto YS. Demonstration of electromagnetic enhancement correlated to optical absorption of single plasmonic system coupled with molecular excitons using ultrafast surface-enhanced fluorescence. J Chem Phys 2023; 159:034709. [PMID: 37466231 DOI: 10.1063/5.0156641] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 06/23/2023] [Indexed: 07/20/2023] Open
Abstract
The relationship between the electromagnetic (EM) enhancement of the optical responses of molecules and plasmon resonance has been investigated using Rayleigh scattering or the extinction spectra of plasmonic systems coupled with molecular excitons. However, quantum optics predicts that the EM enhancement of such optical responses, e.g., fluorescence, Raman, and their nonlinear counterparts, is related directly to optical absorption and indirectly to Rayleigh scattering and extinction. To demonstrate this prediction, a micro-spectroscopic method for obtaining Rayleigh scattering, extinction, absorption, and EM enhancement is developed using single-coupled plasmonic systems composed of silver nanoparticle dimers and dye molecules. The EM enhancement is derived from ultrafast surface-enhanced fluorescence. An evaluation of the spectral relationships demonstrates that the EM enhancement can be reproduced better by absorption than by Rayleigh scattering or extinction. This reproduction is phenomenologically confirmed by numerical calculations based on classical electromagnetism, indicating the importance of absorption spectroscopy in coupled plasmonic systems for evaluating EM enhancement.
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Affiliation(s)
- Tamitake Itoh
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu, Kagawa 761-0395, Japan
| | - Yuko S Yamamoto
- School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), Nomi, Ishikawa 923-1292, Japan
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Itoh T, Yamamoto YS. Correlated Polarization Dependences between Surface-Enhanced Resonant Raman Scattering and Plasmon Resonance Elastic Scattering Showing Spectral Uncorrelation to Each Other. J Phys Chem B 2023; 127:4666-4675. [PMID: 37192137 DOI: 10.1021/acs.jpcb.3c01878] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We investigated the origin of the identical polarization angle dependence between surface-enhanced resonant Raman scattering (SERRS) and plasmon resonance elastic scattering (PRES) for two types of single silver nanoparticle aggregates. The first type (Type I), in which the SERRS spectral envelopes are similar to the PRES spectra, shows the identical polarization dependence between the SERRS and PRES. The second type (Type II), in which the SERRS envelopes largely deviate from the PRES spectra, also exhibits identical polarization dependence. Scanning electron microscopy observations indicated that the aggregates were dimers. This unintuitive result was examined by calculating the electromagnetic enhancement by changing the morphology of the dimers. The calculations revealed that the Type I dimer generates SERRS directly by superradiant plasmons. The Type II dimer generates SERRS indirectly via subradiant plasmons, which receive light energy from superradiant plasmons. This indirect SERRS process clarifies that the interaction between the superradiant and subradiant plasmons results in an identical polarization dependence between SERRS and PRES for Type II dimers.
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Affiliation(s)
- Tamitake Itoh
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu, Kagawa 761-0395, Japan
| | - Yuko S Yamamoto
- School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), Nomi, Ishikawa 923-1292, Japan
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Itoh T, Procházka M, Dong ZC, Ji W, Yamamoto YS, Zhang Y, Ozaki Y. Toward a New Era of SERS and TERS at the Nanometer Scale: From Fundamentals to Innovative Applications. Chem Rev 2023; 123:1552-1634. [PMID: 36745738 PMCID: PMC9952515 DOI: 10.1021/acs.chemrev.2c00316] [Citation(s) in RCA: 65] [Impact Index Per Article: 65.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Indexed: 02/08/2023]
Abstract
Surface-enhanced Raman scattering (SERS) and tip-enhanced Raman scattering (TERS) have opened a variety of exciting research fields. However, although a vast number of applications have been proposed since the two techniques were first reported, none has been applied to real practical use. This calls for an update in the recent fundamental and application studies of SERS and TERS. Thus, the goals and scope of this review are to report new directions and perspectives of SERS and TERS, mainly from the viewpoint of combining their mechanism and application studies. Regarding the recent progress in SERS and TERS, this review discusses four main topics: (1) nanometer to subnanometer plasmonic hotspots for SERS; (2) Ångström resolved TERS; (3) chemical mechanisms, i.e., charge-transfer mechanism of SERS and semiconductor-enhanced Raman scattering; and (4) the creation of a strong bridge between the mechanism studies and applications.
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Affiliation(s)
- Tamitake Itoh
- Health
and Medical Research Institute, National
Institute of Advanced Industrial Science and Technology (AIST), 2217-14 Hayashi-cho, Takamatsu, 761-0395Kagawa, Japan
| | - Marek Procházka
- Faculty
of Mathematics and Physics, Institute of Physics, Charles University, Ke Karlovu 5, 121 16Prague 2, Czech Republic
| | - Zhen-Chao Dong
- Hefei
National Research Center for Physical Sciences at the Microscale, University of Science and Technique of China, Hefei230026, China
| | - Wei Ji
- College
of Chemistry, Chemical Engineering, and Resource Utilization, Northeast Forestry University, Harbin145040, China
| | - Yuko S. Yamamoto
- School
of Materials Science, Japan Advanced Institute
of Science and Technology (JAIST), Nomi, 923-1292Ishikawa, Japan
| | - Yao Zhang
- Hefei
National Research Center for Physical Sciences at the Microscale, University of Science and Technique of China, Hefei230026, China
| | - Yukihiro Ozaki
- School of
Biological and Environmental Sciences, Kwansei
Gakuin University, 2-1,
Gakuen, Sanda, 669-1330Hyogo, Japan
- Toyota
Physical and Chemical Research Institute, Nagakute, 480-1192Aichi, Japan
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Itoh T, Yamamoto YS. Between plasmonics and surface-enhanced resonant Raman spectroscopy: toward single-molecule strong coupling at a hotspot. NANOSCALE 2021; 13:1566-1580. [PMID: 33438716 DOI: 10.1039/d0nr07344j] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The purpose of this minireview is to build a bridge between two research fields: surface-enhanced resonant Raman spectroscopy (SERRS) under near-single-molecule conditions and the branch of plasmonics treating strong coupling between plasmons and molecular excitons. SERRS enables single-molecule spectroscopy owing to its significant enhancement at SERRS hotspots (HSs), localized at gaps or junctions between plasmonic nanoparticle aggregates. SERRS is SERS (surface enhanced Raman spectroscopy) under a resonant Raman excitation condition. The origin of the Raman enhancement in SERRS is electromagnetic coupling between plasmons and molecular excitons at HSs. It has been reported that the coupling energy at HSs reaches the strong coupling region, meaning that they are potential platforms for applications of single molecular excitons modified by strong coupling. In this review, we discuss recent progress related to electronic strong coupling in near-single-molecule SERRS: collective (e.g., vibrational) strong coupling is out of the scope of this minireview. First, we explain the relationship between the electromagnetic enhancement factor and coupling energy. Second, we introduce three theoretical methods for obtaining evidence of strong coupling at HSs. Third, we discuss a method for reproducing enhanced and modified molecular Raman and fluorescence spectra at HSs using the coupling energy. Finally, we propose the use of two experimental methods of absorption spectroscopy at HSs for modifying molecular electronic dynamics by strong coupling and comment on future applications of SERRS HSs to photophysics and photochemistry.
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Affiliation(s)
- Tamitake Itoh
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu, Kagawa 761-0395, Japan.
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Cortés E, Govorov AO, Misawa H, Willets KA. Special topic on emerging directions in plasmonics. J Chem Phys 2020; 153:010401. [PMID: 32640808 DOI: 10.1063/5.0017914] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Plasmonics enables a wealth of applications, including photocatalysis, photoelectrochemistry, photothermal heating, optoelectronic devices, and biological and chemical sensing, while encompassing a broad range of materials, including coinage metals, doped semiconductors, metamaterials, 2D materials, bioconjugates, and chiral assemblies. Applications in plasmonics benefit from the large local electromagnetic field enhancements generated by plasmon excitation, as well as the products of plasmon decay, including photons, hot charge carriers, and heat. This special topic highlights recent work in both theory and experiment that advance our fundamental understanding of plasmon excitation and decay mechanisms, showcase new applications enabled by plasmon excitation, and highlight emerging classes of materials that support plasmon excitation.
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Affiliation(s)
- Emiliano Cortés
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universitat (LMU), 80539 Munich, Germany
| | - Alexander O Govorov
- Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA
| | - Hiroaki Misawa
- Research Institute for Electronic Science, Hokkaido University, Sapporo, Hokkaido 001-0021, Japan and Center for Emergent Functional Matter Science, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan
| | - Katherine A Willets
- Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, USA
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