101
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Chirumamilla M, Toma A, Gopalakrishnan A, Das G, Zaccaria RP, Krahne R, Rondanina E, Leoncini M, Liberale C, De Angelis F, Di Fabrizio E. 3D nanostar dimers with a sub-10-nm gap for single-/few-molecule surface-enhanced raman scattering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:2353-2358. [PMID: 24452910 DOI: 10.1002/adma.201304553] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 11/09/2013] [Indexed: 06/03/2023]
Abstract
Plasmonic nanostar-dimers, decoupled from the substrate, have been fabricated by combining electron-beam lithography and reactive-ion etching techniques. The 3D architecture, the sharp tips of the nanostars and the sub-10 nm gap size promote the formation of giant electric-field in highly localized hot-spots. The single/few molecule detection capability of the 3D nanostar-dimers has been demonstrated by Surface-Enhanced Raman Scattering.
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Affiliation(s)
- Manohar Chirumamilla
- Nanostructures, Istituto Italiano di Tecnologia, via Morego 30, Genova, 16163, Italy
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102
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Liu H, Yang Z, Meng L, Sun Y, Wang J, Yang L, Liu J, Tian Z. Three-Dimensional and Time-Ordered Surface-Enhanced Raman Scattering Hotspot Matrix. J Am Chem Soc 2014; 136:5332-41. [DOI: 10.1021/ja501951v] [Citation(s) in RCA: 261] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Honglin Liu
- Institute
of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031, China
| | - Zhilin Yang
- State
Key Laboratory of Physical Chemistry of Solid Surfaces and College
of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Lingyan Meng
- State
Key Laboratory of Physical Chemistry of Solid Surfaces and College
of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yudie Sun
- Institute
of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031, China
| | - Jie Wang
- Shanghai
Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China
| | - Liangbao Yang
- Institute
of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031, China
| | - Jinhuai Liu
- Institute
of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031, China
| | - Zhongqun Tian
- State
Key Laboratory of Physical Chemistry of Solid Surfaces and College
of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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103
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Lee J, Hua B, Park S, Ha M, Lee Y, Fan Z, Ko H. Tailoring surface plasmons of high-density gold nanostar assemblies on metal films for surface-enhanced Raman spectroscopy. NANOSCALE 2014; 6:616-623. [PMID: 24247586 DOI: 10.1039/c3nr04752k] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Plasmonic systems based on metal nanoparticles on a metal film have generated great interest for surface-enhanced Raman spectroscopy (SERS) chemical sensors. In this study, we describe the fabrication of ultrasensitive SERS substrates based on high-density gold nanostar assemblies on silver films with tailored surface plasmons, where multiple field enhancements from particle-film and interparticle plasmon couplings and lightening rod effects of sharp tips of nanostars contribute to the enormous Raman enhancements. We show that the interplay between interparticle and particle-film plasmon couplings of high-density gold nanostars (GNSs) on metal and dielectric films as a function of interparticle separation can be tailored to provide maximum SERS effects. We observe that the SERS enhancement factor (EF) of GNSs on a metal film as a function of interparticle separation follows a broken power law function, where the EF increases with the interparticle separation for the strong interparticle coupling range below an interparticle separation of ~0.8 times the GNS size, but decreases for the weak interparticle coupling range (for an interparticle separation of >0.8 times the GNS size). Finally, we demonstrate the use of tailored plasmonic substrates as ultrasensitive SERS chemical sensors with an attomole level of detection capability of 2,4-dinitrotoluene, a model compound of nitroaromatic explosives.
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Affiliation(s)
- Jiwon Lee
- School of Energy and Chemical Engineering, Ulsan National Institute Science and Technology (UNIST), Ulsan, Republic of Korea.
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104
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Shen X, Mei C, Zhou Y, Xia W, Zhou M, Zeng X. Controlled formation of nanoparticle clusters mediated by electrostatic interaction. RSC Adv 2014. [DOI: 10.1039/c4ra07472f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
A general strategy for high yield fabrication of homo- and hetero-nanoparticle clusters with controlled configuration and inter-particle gap through a self-assembly process mediated by electrostatic interaction was reported.
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Affiliation(s)
- Xiaoshuang Shen
- School of Physical Science and Technology & Institute of Optoelectronic Technology
- Yangzhou University
- Yangzhou 225002, P. R. China
| | - Chao Mei
- School of Physical Science and Technology & Institute of Optoelectronic Technology
- Yangzhou University
- Yangzhou 225002, P. R. China
| | - Yuxue Zhou
- School of Physical Science and Technology & Institute of Optoelectronic Technology
- Yangzhou University
- Yangzhou 225002, P. R. China
| | - Weiwei Xia
- School of Physical Science and Technology & Institute of Optoelectronic Technology
- Yangzhou University
- Yangzhou 225002, P. R. China
| | - Min Zhou
- School of Physical Science and Technology & Institute of Optoelectronic Technology
- Yangzhou University
- Yangzhou 225002, P. R. China
| | - Xianghua Zeng
- School of Physical Science and Technology & Institute of Optoelectronic Technology
- Yangzhou University
- Yangzhou 225002, P. R. China
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105
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Zhang L, Ma H, Yang L. Design and fabrication of surface-enhanced Raman scattering substrate from DNA–gold nanoparticles assembly with 2–3 nm interparticle gap. RSC Adv 2014. [DOI: 10.1039/c4ra06947a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This study provides a one-step strategy for preparing DNA–Au hybrids as SERS-active substrates by the simple mixing of DNA and Au colloids.
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Affiliation(s)
- Li Zhang
- School of Biological and Chemical Engineering
- Anhui Key Laboratory of Spin Electron and Nanomaterials
- Suzhou University
- Suzhou 234000, PR China
| | - Hongwei Ma
- School of Life Science
- Anhui University
- Hefei 230039, PR China
| | - Liangbao Yang
- Institute of Intelligent Machines
- Chinese Academy of Sciences
- Hefei 230031, China
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106
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Chen J, Shen W, Das B, Li Y, Qin G. Fabrication of tunable Au SERS nanostructures by a versatile technique and application in detecting sodium cyclamate. RSC Adv 2014. [DOI: 10.1039/c4ra01243g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Three tunable Au SERS nanostructures (nanoparticles, nanowire–nanoparticle conjugations, nanofilms) were fabricated and used for sodium cyclamate detection.
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Affiliation(s)
- Jing Chen
- Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education)
- Northeastern University
- Shenyang 110819, China
- Nevada Nanotechnology Center
- Howard R. Hughes College of Engineering
| | - Wen Shen
- Nevada Nanotechnology Center
- Howard R. Hughes College of Engineering
- University of Nevada
- Las Vegas, USA
| | - Biswajit Das
- Nevada Nanotechnology Center
- Howard R. Hughes College of Engineering
- University of Nevada
- Las Vegas, USA
| | - Yiyan Li
- Department of Electrical and Computer Engineering
- University of Nevada
- Las Vegas, USA
| | - Gaowu Qin
- Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education)
- Northeastern University
- Shenyang 110819, China
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107
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Zhang Z, Zhang S, Lin M. DNA-embedded Au–Ag core–shell nanoparticles assembled on silicon slides as a reliable SERS substrate. Analyst 2014; 139:2207-13. [DOI: 10.1039/c3an02116e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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108
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Self-aligned colocalization of 3D plasmonic nanogap arrays for ultra-sensitive surface plasmon resonance detection. Biosens Bioelectron 2014; 51:401-7. [DOI: 10.1016/j.bios.2013.08.008] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 07/31/2013] [Accepted: 08/09/2013] [Indexed: 11/20/2022]
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109
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Mendis MN, Mandal HS, Waldeck DH. Enhanced Sensitivity of Delocalized Plasmonic Nanostructures. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2013; 117:25693-25703. [PMID: 24470837 PMCID: PMC3901052 DOI: 10.1021/jp410000u] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This work reports on the observation of a delocalized surface plasmon resonance (DSPR) phenomenon in linear chains of square-shaped silver nanoparticles (NP) as a function of the chain length and the distance between the nanoparticles in the chain. Transmission spectra of the silver nanoparticle chains reveal the emergence of new, red-shifted extinction peaks that depend strongly on the spacing between the nanoparticles and the polarization of the exciting light with respect to the chain axis. As the spacing between the nanoparticles in the linear chain decreases and the number of nanoparticles in the linear chain increases, the strength of the new extinction features increase strongly. These changes can be described by a tight-binding model for the coupled chain, which indicates that the origin of the phenomenon is consistent with an increased coupling between the nanoparticles. FDTD calculations reveal that the electric field is strongly enhanced between the nanoparticles in the chain. The DSPR response is found to be much more sensitive to dielectric changes than the localized surface plasmon resonance (LSPR).
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110
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Teperik TV, Nordlander P, Aizpurua J, Borisov AG. Quantum effects and nonlocality in strongly coupled plasmonic nanowire dimers. OPTICS EXPRESS 2013; 21:27306-25. [PMID: 24216954 DOI: 10.1364/oe.21.027306] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Using a fully quantum mechanical approach we study the optical response of a strongly coupled metallic nanowire dimer for variable separation widths of the junction between the nanowires. The translational invariance of the system allows to apply the time-dependent density functional theory (TDDFT) for nanowires of diameters up to 10 nm which is the largest size considered so far in quantum modeling of plasmonic dimers. By performing a detailed analysis of the optical extinction, induced charge densities, and near fields, we reveal the major nonlocal quantum effects determining the plasmonic modes and field enhancement in the system. These effects consist mainly of electron tunneling between the nanowires at small junction widths and dynamical screening. The TDDFT results are compared with results from classical electromagnetic calculations based on the local Drude and non-local hydrodynamic descriptions of the nanowire permittivity, as well as with results from a recently developed quantum corrected model. The latter provides a way to include quantum mechanical effects such as electron tunneling in standard classical electromagnetic simulations. We show that the TDDFT results can be thus retrieved semi-quantitatively within a classical framework. We also discuss the shortcomings of classical non-local hydrodynamic approaches. Finally, the implications of the actual position of the screening charge density at the gap interfaces are discussed in connection with plasmon ruler applications at subnanometric distances.
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111
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Jiwei Q, Yudong L, Ming Y, Qiang W, Zongqiang C, Wudeng W, Wenqiang L, Xuanyi Y, Jingjun X, Qian S. Large-area high-performance SERS substrates with deep controllable sub-10-nm gap structure fabricated by depositing Au film on the cicada wing. NANOSCALE RESEARCH LETTERS 2013; 8:437. [PMID: 24148212 PMCID: PMC3816588 DOI: 10.1186/1556-276x-8-437] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Accepted: 09/19/2013] [Indexed: 05/23/2023]
Abstract
Noble metal nanogap structure supports strong surface-enhanced Raman scattering (SERS) which can be used to detect single molecules. However, the lack of reproducible fabrication techniques with nanometer-level control over the gap size has limited practical applications. In this letter, by depositing the Au film onto the cicada wing, we engineer the ordered array of nanopillar structures on the wing to form large-area high-performance SERS substrates. Through the control of the thickness of the Au film deposited onto the cicada wing, the gap sizes between neighboring nanopillars are fine defined. SERS substrates with sub-10-nm gap sizes are obtained, which have the highest average Raman enhancement factor (EF) larger than 2 × 108, about 40 times as large as that of commercial Klarite® substrates. The cicada wings used as templates are natural and environment-friendly. The depositing method is low cost and high throughput so that our large-area high-performance SERS substrates have great advantage for chemical/biological sensing applications.
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Affiliation(s)
- Qi Jiwei
- The MOE Key Laboratory of Weak-Light Nonlinear Photonics, Tianjin Key Laboratory of Photonics and Technology, TEDA Applied Physics School and School of Physics, Nankai University, Tianjin 300457, China
| | - Li Yudong
- The MOE Key Laboratory of Weak-Light Nonlinear Photonics, Tianjin Key Laboratory of Photonics and Technology, TEDA Applied Physics School and School of Physics, Nankai University, Tianjin 300457, China
| | - Yang Ming
- The MOE Key Laboratory of Weak-Light Nonlinear Photonics, Tianjin Key Laboratory of Photonics and Technology, TEDA Applied Physics School and School of Physics, Nankai University, Tianjin 300457, China
| | - Wu Qiang
- The MOE Key Laboratory of Weak-Light Nonlinear Photonics, Tianjin Key Laboratory of Photonics and Technology, TEDA Applied Physics School and School of Physics, Nankai University, Tianjin 300457, China
| | - Chen Zongqiang
- The MOE Key Laboratory of Weak-Light Nonlinear Photonics, Tianjin Key Laboratory of Photonics and Technology, TEDA Applied Physics School and School of Physics, Nankai University, Tianjin 300457, China
| | - Wang Wudeng
- The MOE Key Laboratory of Weak-Light Nonlinear Photonics, Tianjin Key Laboratory of Photonics and Technology, TEDA Applied Physics School and School of Physics, Nankai University, Tianjin 300457, China
| | - Lu Wenqiang
- The MOE Key Laboratory of Weak-Light Nonlinear Photonics, Tianjin Key Laboratory of Photonics and Technology, TEDA Applied Physics School and School of Physics, Nankai University, Tianjin 300457, China
| | - Yu Xuanyi
- The MOE Key Laboratory of Weak-Light Nonlinear Photonics, Tianjin Key Laboratory of Photonics and Technology, TEDA Applied Physics School and School of Physics, Nankai University, Tianjin 300457, China
| | - Xu Jingjun
- The MOE Key Laboratory of Weak-Light Nonlinear Photonics, Tianjin Key Laboratory of Photonics and Technology, TEDA Applied Physics School and School of Physics, Nankai University, Tianjin 300457, China
| | - Sun Qian
- The MOE Key Laboratory of Weak-Light Nonlinear Photonics, Tianjin Key Laboratory of Photonics and Technology, TEDA Applied Physics School and School of Physics, Nankai University, Tianjin 300457, China
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112
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Siegfried T, Ekinci Y, Martin OJF, Sigg H. Gap plasmons and near-field enhancement in closely packed sub-10 nm gap resonators. NANO LETTERS 2013; 13:5449-5453. [PMID: 24111580 DOI: 10.1021/nl403030g] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Pairs of metal nanoparticles with a sub-10 nm gap are an efficient way to achieve extreme near-field enhancement for sensing applications. We demonstrate an attractive alternative based on Fabry-Perot type nanogap resonators, where the resonance is defined by the gap width and vertical elongation instead of the particle geometry. We discuss the crucial design parameters for such gap plasmons to produce maximum near-field enhancement for surface-enhanced Raman scattering and show compatibility of the pattern processing with low-cost and low-resolution lithography. We find a minimum critical metal thickness of 80 nm and observe that the mode coupling from the far field increases by tapering the gap opening. We also show the saturation of the Raman signal for nanogap periodicities below 1 μm, demonstrating efficient funneling of light into such nanogap arrays.
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Affiliation(s)
- Thomas Siegfried
- Laboratory for Micro- and Nanotechnology, Paul Scherrer Institut , 5232 Villigen-PSI, Switzerland
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113
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Silver nano islands enhanced Raman scattering on large area grating substrates fabricated by two beam laser interference. Chem Res Chin Univ 2013. [DOI: 10.1007/s40242-013-3080-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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114
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Zhu C, Meng G, Huang Q, Zhang Y, Tang H, Qian Y, Chen B, Wang X. Ostwald-Ripening-Induced Growth of Parallel Face-Exposed Ag Nanoplates on Micro-Hemispheres for High SERS Activity. Chemistry 2013; 19:9211-7. [DOI: 10.1002/chem.201300454] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Indexed: 11/07/2022]
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115
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Chen J, Qin G, Wang J, Yu J, Shen B, Li S, Ren Y, Zuo L, Shen W, Das B. One-step fabrication of sub-10-nm plasmonic nanogaps for reliable SERS sensing of microorganisms. Biosens Bioelectron 2013; 44:191-7. [DOI: 10.1016/j.bios.2013.01.038] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 12/31/2012] [Accepted: 01/21/2013] [Indexed: 12/23/2022]
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116
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Duan H, Hu H, Hui HK, Shen Z, Yang JKW. Free-standing sub-10 nm nanostencils for the definition of gaps in plasmonic antennas. NANOTECHNOLOGY 2013; 24:185301. [PMID: 23579281 DOI: 10.1088/0957-4484/24/18/185301] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Nanogaps between metal nanostructures are useful in localizing optical energy in plasmonic antennas, but are challenging to directly pattern. Patterning with the positive-tone polymethyl methacrylate (PMMA) resist causes an undesirable spread in nanogap dimensions. On the other hand, the negative-tone hydrogen silsesquioxane (HSQ) resist possesses the high resolution suited for the definition of nanogaps. However, it requires a hydrofluoric acid solution for liftoff, making it incompatible with the quartz or glass substrates used in optical devices. In this work, we created free-standing nanostencils in HSQ with sub-10 nm dimensions onto PMMA supports, which allow liftoff in organic solvents, thus extending this method to a broad range of substrate materials. The cross-sectional profiles of the nanogaps formed between the gold nanostructures were imaged in a transmission electron microscope and measured to be ~8 nm. We demonstrated the utility of this process in fabricating entire arrays of dimer nanostructures with sub-10 nm gaps. Using a surface enhanced Raman scattering setup, an order of magnitude increase in peak intensity was observed when the fields in the gap were resonantly excited compared to when the fields were localized at the corners of the nanostructures.
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Affiliation(s)
- Huigao Duan
- College of Physics and Microelectronics, Hunan University, Changsha 410082, People's Republic of China
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117
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Bochterle J, Neubrech F, Nagao T, Pucci A. Angstrom-scale distance dependence of antenna-enhanced vibrational signals. ACS NANO 2012; 6:10917-10923. [PMID: 23167482 DOI: 10.1021/nn304341c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The resonantly enhanced near-field of micrometer-sized gold antennas has been probed with Angstrom-scale resolution. In situ surface-enhanced infrared spectroscopic vibrational signals of carbon monoxide (CO) layers cold-condensed on the antennas in ultrahigh-vacuum conditions are compared to the signals of CO layers with corresponding thicknesses on a flat gold surface. Vibrational signals of CO as well as the shift of the plasmonic resonance frequency were used to analyze the distance dependence of the near-field. The signal enhancement induced by the antennas not only decays monotonically from the surface but, in contrast to classical near-field models, shows a maximum between 10 and 15 Å and decays also toward the surface of the antenna. This effect is attributed to the spill-out of the electron wave function, as expected from quantum mechanical calculations.
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Affiliation(s)
- Jörg Bochterle
- Kirchhoff Institute for Physics, University of Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
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118
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Yan J, Su S, He S, He Y, Zhao B, Wang D, Zhang H, Huang Q, Song S, Fan C. Nano Rolling-Circle Amplification for Enhanced SERS Hot Spots in Protein Microarray Analysis. Anal Chem 2012; 84:9139-45. [DOI: 10.1021/ac301809e] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Juan Yan
- Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy
of Sciences, Shanghai 201800, China
| | - Shao Su
- Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy
of Sciences, Shanghai 201800, China
| | - Shijiang He
- Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy
of Sciences, Shanghai 201800, China
| | - Yao He
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China
| | - Bin Zhao
- Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy
of Sciences, Shanghai 201800, China
| | - Dongfang Wang
- Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy
of Sciences, Shanghai 201800, China
| | - Honglu Zhang
- Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy
of Sciences, Shanghai 201800, China
| | - Qing Huang
- Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy
of Sciences, Shanghai 201800, China
| | - Shiping Song
- Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy
of Sciences, Shanghai 201800, China
| | - Chunhai Fan
- Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy
of Sciences, Shanghai 201800, China
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119
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Li Z, Meng G, Huang Q, Zhu C, Zhang Z, Li X. Galvanic-cell-induced growth of Ag nanosheet-assembled structures as sensitive and reproducible SERS substrates. Chemistry 2012; 18:14948-53. [PMID: 23079922 DOI: 10.1002/chem.201201690] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 09/16/2012] [Indexed: 11/11/2022]
Abstract
SERS up: Ag nanosheet-assembled structures with controlled morphologies were achieved on indium tin oxide substrates by galvanic-cell-induced growth (see figure). These structures exhibit a highly active and homogeneous surface-enhanced Raman scattering (SERS) effect, and show promising potential as reliable SERS substrates for detection of trace polychlorinated biphenyls.
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Affiliation(s)
- Zhongbo Li
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, PR China
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120
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Kleinman SL, Frontiera RR, Henry AI, Dieringer JA, Van Duyne RP. Creating, characterizing, and controlling chemistry with SERS hot spots. Phys Chem Chem Phys 2012; 15:21-36. [PMID: 23042160 DOI: 10.1039/c2cp42598j] [Citation(s) in RCA: 368] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In this perspective we discuss the roles of hot spots in surface-enhanced Raman spectroscopy (SERS). After giving background and defining the hot spot, we evaluate a variety of SERS substrates which often contain hot spots. We compare and discuss the differentiating properties of each substrate. We then provide a thorough analysis of the hot spot contribution to the observed SERS signal both in ensemble-averaged and single-molecule conditions. We also enumerate rules for determining the SERS enhancement factor (EF) to clarify the use of this common metric. Finally, we present a forward-looking overview of applications and uses of hot spots for controlling chemistry on the nanoscale. Although not exhaustive, this perspective is a review of some of the most interesting and promising methodologies for creating, controlling, and using hot spots for electromagnetic amplification.
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Affiliation(s)
- Samuel L Kleinman
- Northwestern University, Department of Chemistry, 2145 Sheridan Rd., Evanston, IL 60208, USA
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121
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Shiers MJ, Leech R, Carmalt CJ, Parkin IP, Kenyon AJ. Self-assembled ultra-high aspect ratio silver nanochains. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:5227-5235. [PMID: 22865339 DOI: 10.1002/adma.201202005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Indexed: 06/01/2023]
Affiliation(s)
- Matthew J Shiers
- Department of Electronic & Electrical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.
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122
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Wu HY, Choi CJ, Cunningham BT. Plasmonic nanogap-enhanced Raman scattering using a resonant nanodome array. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2012; 8:2878-85. [PMID: 22761112 DOI: 10.1002/smll.201200712] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Indexed: 05/23/2023]
Abstract
The optical properties and surface-enhanced Raman scattering (SERS) of plasmonic nanodome array (PNA) substrates in air and aqueous solution are investigated. PNA substrates are inexpensively and uniformly fabricated with a hot spot density of 6.25 × 10(6) mm(-2) using a large-area nanoreplica moulding technique on a flexible plastic substrate. Both experimental measurement and numerical simulation results show that PNAs exhibit a radiative localized surface plasmon resonance (LSPR) due to dipolar coupling between neighboring nanodomes and a non-radiative surface plasmon resonance (SPR) resulting from the periodic array structure. The high spatial localization of electromagnetic field within the ∼10 nm nanogap together with the spectral alignment between the LSPR and excited and scattered light results in a reliable and reproducible spatially averaged SERS enhancement factor (EF) of 8.51 × 10(7) for Au-coated PNAs. The SERS enhancement is sufficient for a wide variety of biological and chemical sensing applications, including detection of common metabolites at physiologically relevant concentrations.
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Affiliation(s)
- Hsin-Yu Wu
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, 208 North Wright Street, Urbana, IL 61801, USA
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123
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Neubrech F, Weber D, Katzmann J, Huck C, Toma A, Di Fabrizio E, Pucci A, Härtling T. Infrared optical properties of nanoantenna dimers with photochemically narrowed gaps in the 5 nm regime. ACS NANO 2012; 6:7326-7332. [PMID: 22804706 DOI: 10.1021/nn302429g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In this paper, we report on the manipulation of the near-field coupling in individual gold nanoantenna dimers resonant in the infrared (IR) spectral range. Photochemical metal deposition onto lithographically fabricated nanoantennas is used to decrease the gap between the antenna arms down to below 4 nm, as confirmed by finite-difference time-domain simulations. The increased plasmonic coupling in the gap region leads to a shift of the surface plasmon resonances to lower energies as well as to the appearance of hybridized plasmonic modes. All of the occurring electron oscillation modes can be explained by the plasmon hybridization model. Besides the bonding combination of the fundamental resonances of individual antennas, also the antibonding combination is observed in the IR transmittance at normal incidence. Its appearance is due to both structural defects and the small gaps between the antennas. The detailed analysis of individual IR antennas presented here allows a profound understanding of the spectral features occurring during the photochemical manipulation process and therefore paves the way to a full optical process monitoring of sub-nanometer scale gaps, which may serve as model systems for experimental studies of quantum mechanical effects in plasmonics.
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Affiliation(s)
- Frank Neubrech
- Kirchhoff Institute for Physics, University of Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany.
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124
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Drozdowicz-Tomsia K, Baltar HTMCM, Goldys EM. Dense two-dimensional silver single and double nanoparticle arrays with plasmonic response in wide spectral range. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:9071-9081. [PMID: 22439753 DOI: 10.1021/la300277m] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report the properties of plasmons in dense planar arrays of silver single and double nanostructures with various geometries fabricated by electron beam lithography (EBL) as a function of their size and spacing. We demonstrate a strong plasmon coupling mechanism due to near-field dipolar interactions between adjacent nanostructures, which produces a major red shift of the localized surface plasmon resonance (LSPR) in silver nanoparticles and leads to strong maximum electric field enhancements in a broad spectral range. The extinction spectra and maximum electric field enhancements are theoretically modeled by using the finite element method. Our modeling revealed that strong averaged electric field enhancements of up to 60 in visible range and up to 40 in mid-infrared result from hybridization of multipolar resonances in such dense nanostructures; these are important for applications in surface enhanced spectroscopies.
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125
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Pavaskar P, Theiss J, Cronin SB. Plasmonic hot spots: nanogap enhancement vs. focusing effects from surrounding nanoparticles. OPTICS EXPRESS 2012; 20:14656-62. [PMID: 22714527 DOI: 10.1364/oe.20.014656] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Thin Au films (~5 nm) are known to form island-like structures with small gaps between the islands, which produce intense electric field "hot spots" under visible illumination. In this work, we perform finite difference time domain (FDTD) simulations based on experimentally observed high resolution transmission electron microscope (HRTEM) images of these films in order to study the nature of the "hot spots" in more detail. Specifically, we study the dependence of the electric field intensity in the hot spots on the surrounding film environment and on the size of the nanogaps. From our simulations, we show that the surrounding film contributes significantly to the electric field intensity at the hot spot by focusing energy to it. Widening of the gap size causes a decrease in the intensity at the hot spot. However, these island-like nanoparticle hot spots are far less sensitive to gap size than nanoparticle dimer geometries, studied previously. In fact, the main factor in determining the hot spot intensity is the focusing effect of the surrounding nano-islands. We show that these random Au island films outperform more sophisticated geometries of spherical nanoparticle clusters that have been optimized using an iterative optimization algorithm.
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Affiliation(s)
- Prathamesh Pavaskar
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA
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126
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Gong X, Bao Y, Qiu C, Jiang C. Individual nanostructured materials: fabrication and surface-enhanced Raman scattering. Chem Commun (Camb) 2012; 48:7003-18. [PMID: 22683862 DOI: 10.1039/c2cc31603j] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The progress of surface-enhanced Raman scattering (SERS) microscopy and spectroscopy on individual nanostructured materials has been reviewed in this feature article. After a brief introduction on individual nanomaterial SERS, we provide a systematic overview on the fabrication and SERS studies of individual nanoparticulates, nano-junctions and hierarchical nano-aggregate. These SERS-active nanomaterials have great potential in designing novel highly sensitive SERS substrates for the development of SERS-based sensing devices with a broad range of applications.
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Affiliation(s)
- Xiao Gong
- Department of Chemistry, University of South Dakota, Vermillion, South Dakota 57069, USA
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127
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Shan G, Zheng S, Chen S, Chen Y, Liu Y. Multifunctional ZnO/Ag nanorod array as highly sensitive substrate for surface enhanced Raman detection. Colloids Surf B Biointerfaces 2012; 94:157-62. [DOI: 10.1016/j.colsurfb.2012.01.037] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 12/25/2011] [Accepted: 01/23/2012] [Indexed: 10/14/2022]
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128
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Oh YJ, Jeong KH. Glass nanopillar arrays with nanogap-rich silver nanoislands for highly intense surface enhanced Raman scattering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:2234-2237. [PMID: 22454295 DOI: 10.1002/adma.201104696] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 01/25/2012] [Indexed: 05/31/2023]
Abstract
The enhancement of surface enhanced Raman scattering (SERS) with nanogap-rich silver nanoislands surrounding glass nanopillars at wafer level is reported. High-density hot spots are generated by increasing the number of nanogap-rich nanoislands within a detection volume. The SERS substrate shows a high enhancement factor of over 10(7) with excellent signal uniformity (∼7.8%) and it enables the label-free detection of aqueous DNA base molecules at nanomolar level.
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Affiliation(s)
- Young-Jae Oh
- Department of Bio and Brain Engineering, KAIST Institute for Optical Science and Technology, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, Korea
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129
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Yang Y, Li ZY, Yamaguchi K, Tanemura M, Huang Z, Jiang D, Chen Y, Zhou F, Nogami M. Controlled fabrication of silver nanoneedles array for SERS and their application in rapid detection of narcotics. NANOSCALE 2012; 4:2663-9. [PMID: 22410821 DOI: 10.1039/c2nr12110g] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Novel surface-enhanced Raman scattering (SERS) substrates with high SERS-activity are ideal for novel SERS sensors, detectors to detect illicitly sold narcotics and explosives. The key to the wider application of SERS technique is to develop plasmon resonant structure with novel geometries to enhance Raman signals and to control the periodic ordering of these structures over a large area to obtain reproducible Raman enhancement. In this work, a simple Ar(+)-ion sputtering route has been developed to fabricate silver nanoneedles arrays on silicon substrates for SERS-active substrates to detect trace-level illicitly sold narcotics. These silver nanoneedles possess a very sharp apex with an apex diameter of 15 nm and an apex angle of 20°. The SERS enhancement factor of greater than 10(10) was reproducibly achieved by the well-aligned nanoneedles arrays. Furthermore, ketamine hydrochloride molecules, one kind of illicitly sold narcotics, can be detected down to 27 ppb by using our SERS substrate within 3 s, indicating the sensitivity of our SERS substrates for trace amounts of narcotics and that SERS technology can become an important analytical technique in forensic laboratories because it can provide a rapid and nondestructive method for trace detection.
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Affiliation(s)
- Yong Yang
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, P. R. China.
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130
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Shen Y, Liu M, Wang Q, Zhan P, Wang Z, Zhu Q, Chen X, Jiang S, Wang X, Jin C. Fabrication of non-planar silver nano-arc-gap arrays. NANOSCALE 2012; 4:2255-2259. [PMID: 22398454 DOI: 10.1039/c2nr30152k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We developed a method to fabricate an array of silver non-planar nano-arc-gaps via inverted hemispherical colloidal lithography and shadow metal evaporation methods. It is found that there is a localized surface plasmon mode which results in extraordinary optical transmission. The electric field is strongly localized at the nano-arc-gap region and therefore induces a resonance that has an ultra-small mode volume of less than 2.44 × 10(-6) μm(3). The ratio of the quality factor to the mode volume is as high as 1.44 × 10(6) μm(-3). This would be valuable for the design of optoelectric circuits.
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Affiliation(s)
- Yang Shen
- State Key laboratory of optoelectronic materials and technologies, School of Physics and Engineering, Sun Yat-Sen University, Guangzhou, 510275, China
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131
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Tsai CY, Lin JW, Wu CY, Lin PT, Lu TW, Lee PT. Plasmonic coupling in gold nanoring dimers: observation of coupled bonding mode. NANO LETTERS 2012; 12:1648-1654. [PMID: 22321005 DOI: 10.1021/nl300012m] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We investigate the optical properties of gold nanoring (NR) dimers in both simulation and experiment. The resonance peak wavelength of gold NR dimers is strongly dependent on the polarization direction and gap distance. As the gold NR particles approach each other, exponential red shift and slight blue shift of coupled bonding (CB) mode in gold NR dimers for longitudinal and transverse polarizations are obtained. In finite element method analysis, a very strong surface plasmon coupling in the gap region of gold NR dimers is observed, whose field intensity at the gap distance of 10 nm is enhanced 23% compared to that for gold nanodisk (ND) dimers with the same diameter. In addition, plasmonic dimer system exhibits a great improvement in the sensing performance. Near-field coupling in gold NR dimers causes exponential increase in sensitivity to refractive index of surrounding medium with decreasing the gap distance. Compared with coupled dipole mode in gold ND dimers, CB mode in gold NR dimers shows higher index sensitivity. This better index sensing performance is resulted form the additional electric field in inside region of NR and the larger field enhancement in the gap region owing to the stronger coupling of collective dipole plasmon resonances for CB mode. These results pave the way to design plasmonic nanostructures for practical applications that require coupled metallic nanoparticles with enhanced electric fields.
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Affiliation(s)
- Chia-Yang Tsai
- Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Room 415 CPT building, 1001 Ta-Hsueh Road, Hsinchu 300, Taiwan
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132
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Marinica DC, Kazansky AK, Nordlander P, Aizpurua J, Borisov AG. Quantum plasmonics: nonlinear effects in the field enhancement of a plasmonic nanoparticle dimer. NANO LETTERS 2012; 12:1333-9. [PMID: 22320125 DOI: 10.1021/nl300269c] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A fully quantum mechanical investigation using time-dependent density functional theory reveals that the field enhancement in a coupled nanoparticle dimer can be strongly affected by nonlinear effects. We show that both classical as well as linear quantum mechanical descriptions of the system fail even for moderate incident light intensities. An interparticle current resulting from the strong field photoemission tends to neutralize the plasmon-induced surface charge densities on the opposite sides of the nanoparticle junction. Thus, the coupling between the two nanoparticles and the field enhancement is reduced as compared to linear theory. A substantial nonlinear effect is revealed already at incident powers of 10(9) W/cm(2) for interparticle separation distances as large as 1 nm and down to the touching limit.
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Affiliation(s)
- D C Marinica
- Institut des Sciences Moléculaires d'Orsay, UMR 8214 CNRS-Université Paris-Sud, Bâtiment 351, 91405 Orsay Cedex, France
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133
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Huang YF, Wu DY, Zhu HP, Zhao LB, Liu GK, Ren B, Tian ZQ. Surface-enhanced Raman spectroscopic study of p-aminothiophenol. Phys Chem Chem Phys 2012; 14:8485-97. [DOI: 10.1039/c2cp40558j] [Citation(s) in RCA: 219] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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134
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Zhu Y, Kuang H, Xu L, Ma W, Peng C, Hua Y, Wang L, Xu C. Gold nanorodassembly based approach to toxin detection by SERS. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm15238j] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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135
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Heo CJ, Jeon HC, Lee SY, Jang SG, Cho S, Choi Y, Yang SM. Robust plasmonic sensors based on hybrid nanostructures with facile tunability. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm31958f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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136
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Yan B, Boriskina SV, Reinhard BM. Design and Implementation of Noble Metal Nanoparticle Cluster Arrays for Plasmon Enhanced Biosensing. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2011; 115:24437-24453. [PMID: 22299057 PMCID: PMC3268044 DOI: 10.1021/jp207821t] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Nanoparticle Cluster Arrays (NCAs) are a class of electromagnetic materials that comprise chemically defined nanoparticles assembled into clusters of defined size in an extended deterministic arrangement. NCAs are fabricated through integration of chemically synthesized building blocks into predefined patterns using a hybrid top-down/bottom-up fabrication approach that overcomes some of the limitations of conventional top-down fabrication methods with regard to minimum available feature size and structural complexity. NCAs can sustain near-field interactions between nanoparticles within individual clusters as well as between entire neighboring clusters. The availability of near-field interactions on multiple length scales - together with the ability to further enhance the coupled plasmon modes through photonic modes in carefully designed array morphologies - leads to a multiscale cascade electromagnetic field enhancement throughout the array. This feature article introduces the design and fabrication fundamentals of NCAs and characterizes the electromagnetic coupling mechanisms in the arrays. Furthermore, it reviews how the optical properties of NCAs can be tuned through the size and shape of the nanoparticle building blocks and the geometry, size, and separation of the assembled clusters. NCAs have potential applications in many different areas; this feature article focuses on plasmon enhanced biosensing and surface enhanced Raman spectroscopy (SERS), in particular.
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Affiliation(s)
- Bo Yan
- Department of Chemistry and The Photonics Center, Boston University, Boston, MA 02215
| | - Svetlana V. Boriskina
- Department of Chemistry and The Photonics Center, Boston University, Boston, MA 02215
| | - Björn M. Reinhard
- Department of Chemistry and The Photonics Center, Boston University, Boston, MA 02215
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137
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Panagopoulou M, Pantiskos N, Photopoulos P, Tang J, Tsoukalas D, Raptis YS. Raman enhancement of rhodamine adsorbed on Ag nanoparticles self-assembled into nanowire-like arrays. NANOSCALE RESEARCH LETTERS 2011; 6:629. [PMID: 22168792 PMCID: PMC3278473 DOI: 10.1186/1556-276x-6-629] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 12/14/2011] [Indexed: 05/29/2023]
Abstract
This work reports on Raman scattering of rhodamine (R6G) molecules absorbed on either randomly distributed or grating-like arrays of approximately 8-nm Ag nanoparticles developed by inert gas aggregation. Optimal growth and surface-enhanced Raman scattering (SERS) parameters have been obtained for the randomly distributed nanoparticles, while effects related to the aging of the silver nanoparticles were studied. Grating-like arrays of nanoparticles have been fabricated using line arrays templates formed either by fracture-induced structuring or by standard lithographic techniques. Grating structures fabricated by both methods exhibit an enhancement of the SERS signal, in comparison to the corresponding signal from randomly distributed Ag nanoparticles, as well as a preferential enhancement in the areas of the sharp features, and a dependence on the polarization direction of the incident exciting laser beam, with respect to the orientation of the gratings structuring. The observed spectroscopic features are consistent with a line-arrangement of hot-spots due to the self- alignment of metallic nanoparticles, induced by the grating-like templates.
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Affiliation(s)
- Marianthi Panagopoulou
- Physics Department, School of Applied Mathematical and Physical Sciences, National Technical University of Athens, Zografou Campus, Zografou, Athens 157 80, Greece
| | - Nikolaos Pantiskos
- Physics Department, School of Applied Mathematical and Physical Sciences, National Technical University of Athens, Zografou Campus, Zografou, Athens 157 80, Greece
| | - Panos Photopoulos
- Department of Electronics, Technological Educational Institute of Athens, 12210 Aegaleo, Greece
| | - Jun Tang
- North University of China, Taiyuan, Shanxi, People's Republic of China
| | - Dimitris Tsoukalas
- Physics Department, School of Applied Mathematical and Physical Sciences, National Technical University of Athens, Zografou Campus, Zografou, Athens 157 80, Greece
- Institute of Microelectronics, NCSR "Demokritos", GR 15310 Ag. Paraskevi Greece
| | - Yannis S Raptis
- Physics Department, School of Applied Mathematical and Physical Sciences, National Technical University of Athens, Zografou Campus, Zografou, Athens 157 80, Greece
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138
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High concentration silver nanoparticles stably dispersed in water without chemical reagent. J Photochem Photobiol A Chem 2011. [DOI: 10.1016/j.jphotochem.2011.10.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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139
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Duan H, Hu H, Kumar K, Shen Z, Yang JKW. Direct and reliable patterning of plasmonic nanostructures with sub-10-nm gaps. ACS NANO 2011; 5:7593-600. [PMID: 21846105 DOI: 10.1021/nn2025868] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Nanoscale gaps in metal films enable strong field enhancements in plasmonic structures. However, the reliable fabrication of ultrasmall gaps (<10 nm) for real applications is still challenging. In this work, we report a method to directly and reliably fabricate sub-10-nm gaps in plasmonic structures without restrictions on pattern design. This method is based on a lift-off process using high-resolution electron-beam lithography with a negative-tone hydrogen silsesquioxane (HSQ) resist, where the resulting nanogap size is determined by the width of the patterned HSQ structure, which could be written at less than 10 nm. With this method, we fabricated densely packed gold nanostructures of varying geometries separated by ultrasmall gaps. By controlling structure sizes during lithography with nanometer precision, the plasmon resonances of the resulting patterns could be accurately tuned. Optical and surface-enhanced Raman scattering (SERS) measurements on the patterned structures show that this technique has promising applications in the fabrication of passively tunable plasmonic nanostructures with ultrasmall gaps.
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Affiliation(s)
- Huigao Duan
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, 117602 Singapore
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140
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Xu X, Peng B, Li D, Zhang J, Wong LM, Zhang Q, Wang S, Xiong Q. Flexible visible-infrared metamaterials and their applications in highly sensitive chemical and biological sensing. NANO LETTERS 2011; 11:3232-3238. [PMID: 21696183 DOI: 10.1021/nl2014982] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Flexible electronic and photonic devices have been demonstrated in the past decade, with significant promise in low-cost, light-weighted, transparent, biocompatible, and portable devices for a wide range of applications. Herein, we demonstrate a flexible metamaterial (Metaflex)-based photonic device operating in the visible-IR regime, which shows potential applications in high sensitivity strain, biological and chemical sensing. The metamaterial structure, consisting of split ring resonators (SRRs) of 30 nm thick Au or Ag, has been fabricated on poly(ethylene naphthalate) substrates with the least line width of ∼30 nm by electron beam lithography. The absorption resonances can be tuned from middle IR to visible range. The Ag U-shaped SRRs metamaterials exhibit an electric resonance of ∼542 nm and a magnetic resonance of ∼756 nm. Both the electric and magnetic resonance modes show highly sensitive responses to out-of-plane bending strain, surrounding dielectric media, and surface chemical environment. Due to the electric and magnetic field coupling, the magnetic response gives a sensitivity as high as 436 nm/RIU. Our Metaflex devices show superior responses with a shift of magnetic resonance of 4.5 nm/nM for nonspecific bovine serum albumin protein binding and 65 nm for a self-assembled monolayer of 2-naphthalenethiol, respectively, suggesting considerable promise in flexible and transparent photonic devices for chemical and biological sensing.
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Affiliation(s)
- Xinlong Xu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
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141
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Lim DK, Jeon KS, Hwang JH, Kim H, Kwon S, Suh YD, Nam JM. Highly uniform and reproducible surface-enhanced Raman scattering from DNA-tailorable nanoparticles with 1-nm interior gap. NATURE NANOTECHNOLOGY 2011; 6:452-60. [PMID: 21623360 DOI: 10.1038/nnano.2011.79] [Citation(s) in RCA: 676] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 04/21/2011] [Indexed: 05/17/2023]
Abstract
An ideal surface-enhanced Raman scattering (SERS) nanostructure for sensing and imaging applications should induce a high signal enhancement, generate a reproducible and uniform response, and should be easy to synthesize. Many SERS-active nanostructures have been investigated, but they suffer from poor reproducibility of the SERS-active sites, and the wide distribution of their enhancement factor values results in an unquantifiable SERS signal. Here, we show that DNA on gold nanoparticles facilitates the formation of well-defined gold nanobridged nanogap particles (Au-NNP) that generate a highly stable and reproducible SERS signal. The uniform and hollow gap (∼1 nm) between the gold core and gold shell can be precisely loaded with a quantifiable amount of Raman dyes. SERS signals generated by Au-NNPs showed a linear dependence on probe concentration (R(2) > 0.98) and were sensitive down to 10 fM concentrations. Single-particle nano-Raman mapping analysis revealed that >90% of Au-NNPs had enhancement factors greater than 1.0 × 10(8), which is sufficient for single-molecule detection, and the values were narrowly distributed between 1.0 × 10(8) and 5.0 × 10(9).
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Affiliation(s)
- Dong-Kwon Lim
- Department of Chemistry, Seoul National University, Seoul, 151-747, South Korea
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142
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Halas NJ, Lal S, Chang WS, Link S, Nordlander P. Plasmons in Strongly Coupled Metallic Nanostructures. Chem Rev 2011; 111:3913-61. [DOI: 10.1021/cr200061k] [Citation(s) in RCA: 2420] [Impact Index Per Article: 186.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Naomi J. Halas
- Department of Electrical and Computer Engineering, ‡Department of Chemistry, and §Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Surbhi Lal
- Department of Electrical and Computer Engineering, ‡Department of Chemistry, and §Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Wei-Shun Chang
- Department of Electrical and Computer Engineering, ‡Department of Chemistry, and §Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Stephan Link
- Department of Electrical and Computer Engineering, ‡Department of Chemistry, and §Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Peter Nordlander
- Department of Electrical and Computer Engineering, ‡Department of Chemistry, and §Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
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143
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Ahmed A, Gordon R. Directivity enhanced Raman spectroscopy using nanoantennas. NANO LETTERS 2011; 11:1800-3. [PMID: 21428381 DOI: 10.1021/nl200461w] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Directing the emission from optical emitters is highly desired for efficient detection and, by reciprocity, efficient excitation as well. As a scattering process, Raman benefits from directivity enhancements in both excitation and emission. Here we demonstrate directivity enhanced Raman scattering (DERS) using a nanoantenna fabricated by focused ion beam milling. The nanoantenna uses a resonant ring-reflector to shape the emitted beam and achieve DERS-this configuration is most similar to a waveguide antenna. The ring reflector boosts the measured Raman signal by a factor of 5.5 (as compared to the ground plane alone), and these findings are in quantitative agreement with comprehensive numerical simulations. The present design is nearly optimal in the sense that almost all the beam power is coupled into the numerical aperture of the microscope. Furthermore, the emission is directed out of the plane, so that this design can be used to achieve DERS using conventional Raman microscopes, which has yet to be achieved with Yagi-Uda and traveling wave antenna designs.
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Affiliation(s)
- Aftab Ahmed
- Department of Electrical and Computer Engineering, University of Victoria, Victoria, British Columbia V8W 3P6, Canada
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144
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Zuloaga J, Nordlander P. On the energy shift between near-field and far-field peak intensities in localized plasmon systems. NANO LETTERS 2011; 11:1280-3. [PMID: 21319841 DOI: 10.1021/nl1043242] [Citation(s) in RCA: 169] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The localized plasmons of metallic nanoparticles and nanostructures are known to display an interesting and apparently universal phenomenon: upon optical excitation, the maximum near-field enhancements occur at lower energies than the maximum of the corresponding far-field spectrum. Here we present an explanation for this behavior, showing that it results directly from the physics of a driven and damped harmonic oscillator. We show that the magnitude of the shift between the near- and far-field peak intensities depends directly on the total damping of the system, whether it is intrinsic damping within the metal of the nanoparticle or radiative damping of the localized plasmon.
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Affiliation(s)
- Jorge Zuloaga
- Laboratory for Nanophotonics, M.S. 61, Rice University , Houston, Texas 77005-1892, United States
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145
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Fan M, Andrade GFS, Brolo AG. A review on the fabrication of substrates for surface enhanced Raman spectroscopy and their applications in analytical chemistry. Anal Chim Acta 2011; 693:7-25. [PMID: 21504806 DOI: 10.1016/j.aca.2011.03.002] [Citation(s) in RCA: 501] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 02/24/2011] [Accepted: 03/01/2011] [Indexed: 11/16/2022]
Abstract
This work reviews different types of substrates used for surface-enhanced Raman scattering (SERS) that have been developed in the last 10 years. The different techniques of self-assembly to immobilize metallic nanoparticles on solid support are covered. An overview of SERS platforms developed using nanolithography methods, including electron-beam (e-beam) lithography and focused ion beam (FIB) milling are also included, together with several examples of template-based methodologies to generate metallic nano-patterns. The potential of SERS to impact several aspects of analytical chemistry is demonstrated by selected examples of applications in electrochemistry, biosensing, environmental analysis, and remote sensing. This review shows that highly enhancing SERS substrates with a high degree of reliability and reproducibility can now be fabricated at relative low cost, indicating that SERS may finally realize its full potential as a very sensitive tool for routine analytical applications.
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Affiliation(s)
- Meikun Fan
- Department of Mechanical and Material Engineering, University of Western Ontario, London, Canada
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Hatab NA, Hsueh CH, Gaddis AL, Retterer ST, Li JH, Eres G, Zhang Z, Gu B. Free-standing optical gold bowtie nanoantenna with variable gap size for enhanced Raman spectroscopy. NANO LETTERS 2010; 10:4952-5. [PMID: 21090585 DOI: 10.1021/nl102963g] [Citation(s) in RCA: 223] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We describe plasmonic interactions in suspended gold bowtie nanoantenna leading to strong electromagnetic field (E) enhancements. Surface-enhanced Raman scattering (SERS) was used to demonstrate the performance of the nanoantenna. In addition to the well-known gap size dependence, up to 2 orders of magnitude additional enhancement is observed with elevated bowties. The overall behavior is described by a SERS enhancement factor exceeding 10(11) along with an anomalously weak power law dependence of E on the gap size in a range from 8 to 50 nm that is attributed to a plasmonic nanocavity effect occurring when the plasmonic interactions enter a strongly coupled regime.
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148
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Halas NJ. Plasmonics: an emerging field fostered by Nano Letters. NANO LETTERS 2010; 10:3816-22. [PMID: 20853888 DOI: 10.1021/nl1032342] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
While studies of surface plasmons on metals have been pursued for decades, the more recent appearance of nanoscience has created a revolution in this field with "Plasmonics" emerging as a major area of research. The direct optical excitation of surface plasmons on metallic nanostructures provides numerous ways to control and manipulate light at nanoscale dimensions. This has stimulated the development of novel optical materials, deeper theoretical insight, innovative new devices, and applications with potential for significant technological and societal impact. Nano Letters has been instrumental in the emergence of plasmonics, providing its readership with rapid advances in this dynamic field.
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Affiliation(s)
- Naomi J Halas
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, Texas 77005-1892, USA.
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