126
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Brosseau CL, Gambardella A, Casadio F, Grzywacz CM, Wouters J, Van Duyne RP. Ad-hoc Surface-Enhanced Raman Spectroscopy Methodologies for the Detection of Artist Dyestuffs: Thin Layer Chromatography-Surface Enhanced Raman Spectroscopy and in Situ On the Fiber Analysis. Anal Chem 2009; 81:3056-62. [DOI: 10.1021/ac802761v] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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127
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McMahon JM, Henry AI, Wustholz KL, Natan MJ, Freeman RG, Van Duyne RP, Schatz GC. Gold nanoparticle dimer plasmonics: finite element method calculations of the electromagnetic enhancement to surface-enhanced Raman spectroscopy. Anal Bioanal Chem 2009; 394:1819-25. [PMID: 19305981 DOI: 10.1007/s00216-009-2738-4] [Citation(s) in RCA: 158] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Accepted: 03/03/2009] [Indexed: 11/24/2022]
Abstract
Finite element method calculations were carried out to determine extinction spectra and the electromagnetic (EM) contributions to surface-enhanced Raman spectroscopy (SERS) for 90-nm Au nanoparticle dimers modeled after experimental nanotags. The calculations revealed that the EM properties depend significantly on the junction region, specifically the distance between the nanoparticles for spacings of less than 1 nm. For extinction spectra, spacings below 1 nm lead to maxima that are strongly red-shifted from the 600-nm plasmon maximum associated with an isolated nanoparticle. This result agrees qualitatively well with experimental transmission electron microscopy images and localized surface plasmon resonance spectra that are also presented. The calculations further revealed that spacings below 0.5 nm, and especially a slight fusing of the nanoparticles to give tiny crevices, leads to EM enhancements of 10(10) or greater. Assuming a uniform coating of SERS molecules around both nanoparticles, we determined that regardless of the separation, the highest EM fields always dominate the SERS signal. In addition, we determined that for small separations less than 3% of the molecules always contribute to greater than 90% of the signal.
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128
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Solomon GC, Andrews DQ, Van Duyne RP, Ratner MA. Electron Transport through Conjugated Molecules: When the π System Only Tells Part of the Story. Chemphyschem 2009; 10:257-64. [DOI: 10.1002/cphc.200800591] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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129
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Bingham JM, Willets KA, Shah NC, Andrew DQ, Van Duyne RP. LSPR Imaging: Simultaneous Single Nanoparticle Spectroscopy and Diffusional Dynamics. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2009; 113:16839-16842. [PMID: 21311722 PMCID: PMC3035199 DOI: 10.1021/jp907377h] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A wide-field localized surface plasmon resonance (LSPR) imaging method using a liquid crystal tunable filter (LCTF) is used to measure the scattering spectra of multiple Ag nanoparticles in parallel. This method provides the ability to characterize moving Ag nanoparticles by measuring the scattering spectra of the particles while simultaneously tracking their motion. Consequently, single particle diffusion coefficients can be determined. As an example, several single Ag nanoprisms are tracked, the LSPR scattering spectrum of each moving particle is obtained, and the single particle diffusion coefficient is determined from its trajectory. Coupling diffusion information with spectral information in real time is a significant advance and addresses many scientific problems, both fundamental and biological, such as cell membrane protein diffusion, functional plasmonic distributions, and nanoparticle growth mechanisms.
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130
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Andrews DQ, Solomon GC, Van Duyne RP, Ratner MA. Single Molecule Electronics: Increasing Dynamic Range and Switching Speed Using Cross-Conjugated Species. J Am Chem Soc 2008; 130:17309-19. [DOI: 10.1021/ja804399q] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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131
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Solomon GC, Andrews DQ, Goldsmith RH, Hansen T, Wasielewski MR, Van Duyne RP, Ratner MA. Quantum Interference in Acyclic Systems: Conductance of Cross-Conjugated Molecules. J Am Chem Soc 2008; 130:17301-8. [DOI: 10.1021/ja8044053] [Citation(s) in RCA: 196] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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132
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Dieringer JA, Wustholz KL, Masiello DJ, Camden JP, Kleinman SL, Schatz GC, Van Duyne RP. Surface-Enhanced Raman Excitation Spectroscopy of a Single Rhodamine 6G Molecule. J Am Chem Soc 2008; 131:849-54. [DOI: 10.1021/ja8080154] [Citation(s) in RCA: 262] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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133
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Camden JP, Dieringer JA, Zhao J, Van Duyne RP. Controlled plasmonic nanostructures for surface-enhanced spectroscopy and sensing. Acc Chem Res 2008; 41:1653-61. [PMID: 18630932 DOI: 10.1021/ar800041s] [Citation(s) in RCA: 392] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
After its discovery more than 30 years ago, surface-enhanced Raman spectroscopy (SERS) was expected to have major impact as a sensitive analytical technique and tool for fundamental studies of surface species. Unfortunately, the lack of reliable and reproducible fabrication methods limited its applicability. In recent years, SERS has enjoyed a renaissance, and there is renewed interest in both the fundamentals and applications of SERS. New techniques for nanofabrication, the design of substrates that maximize the electromagnetic enhancement, and the discovery of single-molecule SERS are driving the resurgence of this field. This Account highlights our group's recent work on SERS. Initially, we discuss SERS substrates that have shown proven reproducibility, stability, and large field enhancement. These substrates enable many analytical applications, such as anthrax detection, chemical warfare agent stimulant detection, and in vitro and in vivo glucose sensing. We then turn to a detailed study of the wavelength and distance dependence of SERS, which further illustrate predictions obtained from the electromagnetic enhancement mechanism. Last, an isotopic labeling technique applied to the rhodamine 6G (R6G)/silver system serves as an additional proof of the existence of single-molecule SERS and explores the dynamical features of this process. This work, in conjunction with theoretical calculations, allows us to comment on the possible role of charge transfer in the R6G/silver system.
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134
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Camden JP, Dieringer JA, Wang Y, Masiello DJ, Marks LD, Schatz GC, Van Duyne RP. Probing the Structure of Single-Molecule Surface-Enhanced Raman Scattering Hot Spots. J Am Chem Soc 2008; 130:12616-7. [DOI: 10.1021/ja8051427] [Citation(s) in RCA: 762] [Impact Index Per Article: 47.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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135
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Solomon GC, Andrews DQ, Hansen T, Goldsmith RH, Wasielewski MR, Van Duyne RP, Ratner MA. Understanding quantum interference in coherent molecular conduction. J Chem Phys 2008; 129:054701. [DOI: 10.1063/1.2958275] [Citation(s) in RCA: 215] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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136
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Yao J, Wells DM, Chan GH, Zeng HY, Ellis DE, Van Duyne RP, Ibers JA. Syntheses, Structures, Physical Properties, and Electronic Properties of Some AMUQ3 Compounds (A = Alkali Metal, M = Cu or Ag, Q = S or Se). Inorg Chem 2008; 47:6873-9. [PMID: 18597423 DOI: 10.1021/ic800424t] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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137
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Solomon GC, Andrews DQ, Van Duyne RP, Ratner MA. When Things Are Not as They Seem: Quantum Interference Turns Molecular Electron Transfer “Rules” Upside Down. J Am Chem Soc 2008; 130:7788-9. [DOI: 10.1021/ja801379b] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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138
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Anker JN, Hall WP, Lyandres O, Shah NC, Zhao J, Van Duyne RP. Biosensing with plasmonic nanosensors. NATURE MATERIALS 2008; 7:442-53. [PMID: 18497851 DOI: 10.1038/nmat2162] [Citation(s) in RCA: 3102] [Impact Index Per Article: 193.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Recent developments have greatly improved the sensitivity of optical sensors based on metal nanoparticle arrays and single nanoparticles. We introduce the localized surface plasmon resonance (LSPR) sensor and describe how its exquisite sensitivity to size, shape and environment can be harnessed to detect molecular binding events and changes in molecular conformation. We then describe recent progress in three areas representing the most significant challenges: pushing sensitivity towards the single-molecule detection limit, combining LSPR with complementary molecular identification techniques such as surface-enhanced Raman spectroscopy, and practical development of sensors and instrumentation for routine use and high-throughput detection. This review highlights several exceptionally promising research directions and discusses how diverse applications of plasmonic nanoparticles can be integrated in the near future.
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139
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Chan GH, Liu ML, Chen LD, Huang FQ, Bugaris DE, Wells DM, Ireland JR, Hersam MC, Van Duyne RP, Ibers JA. Syntheses, Crystal Structures, and Physical Properties of La5Cu6O4S7 and La5Cu6.33O4S7. Inorg Chem 2008; 47:4368-74. [DOI: 10.1021/ic7024796] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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140
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Hall WP, Anker JN, Lin Y, Modica J, Mrksich M, Van Duyne RP. A calcium-modulated plasmonic switch. J Am Chem Soc 2008; 130:5836-7. [PMID: 18402443 DOI: 10.1021/ja7109037] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A plasmonic switch based on the calcium-induced conformational changes of calmodulin is shown to exhibit reversible wavelength modulations in response to changing calcium concentration. The extinction maximum (lambdamax) of a localized surface plasmon resonance (LSPR) sensor functionalized with a novel calmodulin construct, cutinase-calmodulin-cutinase (CutCaMCut), reversibly shifts by 2-3 nm. A high-resolution (HR) LSPR spectrometer with a wavelength resolution (3sigma) of 1.5 x 10-2 nm was developed to detect these wavelength modulations in real-time, providing information about the dynamics and structure of the protein. The rate of conversion from open (Ca2+-bound) to closed (Ca2+-free) calmodulin is shown to be 4-fold faster than the reverse process, with a closing rate of 0.127 s-1 and opening rate of 0.034 s-1. As far as we are aware, this plasmonic switch marks the first use of LSPR spectroscopy to detect reversible conformational changes in an unlabeled protein.
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141
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Andrews DQ, Van Duyne RP, Ratner MA. Stochastic modulation in molecular electronic transport junctions: molecular dynamics coupled with charge transport calculations. NANO LETTERS 2008; 8:1120-1126. [PMID: 18351748 DOI: 10.1021/nl073265l] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The experimental variation in conductance that can be expected through dynamically evolving Au-molecule-Au junctions is approximated using molecular dynamics to model thermal fluctuations and a nonequilibrium Green's function code (Hückel-IV 2.0) to calculate the charge transport. This generates a statistical set of conductance data that can be used to compare directly with experimental results. Experimental measurements on Au-single molecule junctions show a large variation in conductance values between different identically prepared junctions. Our computational results indicate that the Au-Au and the Au-molecule fluctuations provide extensive geometric freedom and an associated broad distribution in calculated conductance values. Our results show agreement with experimental measurements of the low bias voltage conductance and conductance distribution for both thiol-Au and amine-Au linker structures. -
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142
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Liu Y, Chen L, Wu LM, Chan GH, Van Duyne RP. Syntheses, Crystal and Band Structures, and Magnetic and Optical Properties of New CsLnCdTe3 (Ln = La, Pr, Nd, Sm, Gd−Tm, and Lu). Inorg Chem 2008; 47:855-62. [DOI: 10.1021/ic7016402] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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143
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Stiles PL, Dieringer JA, Shah NC, Van Duyne RP. Surface-enhanced Raman spectroscopy. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2008; 1:601-26. [PMID: 20636091 DOI: 10.1146/annurev.anchem.1.031207.112814] [Citation(s) in RCA: 1483] [Impact Index Per Article: 92.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The ability to control the size, shape, and material of a surface has reinvigorated the field of surface-enhanced Raman spectroscopy (SERS). Because excitation of the localized surface plasmon resonance of a nanostructured surface or nanoparticle lies at the heart of SERS, the ability to reliably control the surface characteristics has taken SERS from an interesting surface phenomenon to a rapidly developing analytical tool. This article first explains many fundamental features of SERS and then describes the use of nanosphere lithography for the fabrication of highly reproducible and robust SERS substrates. In particular, we review metal film over nanosphere surfaces as excellent candidates for several experiments that were once impossible with more primitive SERS substrates (e.g., metal island films). The article also describes progress in applying SERS to the detection of chemical warfare agents and several biological molecules.
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144
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Dieringer JA, Lettan RB, Scheidt KA, Van Duyne RP. A Frequency Domain Existence Proof of Single-Molecule Surface-Enhanced Raman Spectroscopy. J Am Chem Soc 2007; 129:16249-56. [DOI: 10.1021/ja077243c] [Citation(s) in RCA: 456] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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145
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Whitney AV, Casadio F, Van Duyne RP. Identification and characterization of artists' red dyes and their mixtures by surface-enhanced Raman spectroscopy. APPLIED SPECTROSCOPY 2007; 61:994-1000. [PMID: 17910797 DOI: 10.1366/000370207781745838] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Silver film over nanospheres (AgFONs) were successfully employed as surface-enhanced Raman spectroscopy (SERS) substrates to characterize several artists' red dyes including: alizarin, purpurin, carminic acid, cochineal, and lac dye. Spectra were collected on sample volumes (1 x 10(-6) M or 15 ng/microL) similar to those that would be found in a museum setting and were found to be higher in resolution and consistency than those collected on silver island films (AgIFs). In fact, to the best of the authors' knowledge, this work presents the highest resolution spectrum of the artists' material cochineal to date. In order to determine an optimized SERS system for dye identification, experiments were conducted in which laser excitation wavelengths were matched with correlating AgFON localized surface plasmon resonance (LSPR) maxima. Enhancements of approximately two orders of magnitude were seen when resonance SERS conditions were met in comparison to non-resonance SERS conditions. Finally, because most samples collected in a museum contain multiple dyestuffs, AgFONs were employed to simultaneously identify individual dyes within several dye mixtures. These results indicate that AgFONs have great potential to be used to identify not only real artwork samples containing a single dye but also samples containing dyes mixtures.
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146
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Shah NC, Lyandres O, Walsh JT, Glucksberg MR, Van Duyne RP. Lactate and Sequential Lactate−Glucose Sensing Using Surface-Enhanced Raman Spectroscopy. Anal Chem 2007; 79:6927-32. [PMID: 17688322 DOI: 10.1021/ac0704107] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lactate production under anaerobic conditions is indicative of human performance levels, fatigue, and hydration. Elevated lactate levels result from several medical conditions including congestive heart failure, hypoxia, and diabetic ketoacidosis. Real-time detection of lactate can therefore be useful for monitoring these medical conditions, posttrauma situations, and in evaluating the physical condition of a person engaged in strenuous activity. This paper represents a proof-of-concept demonstration of a lactate sensor based on surface-enhanced Raman spectroscopy (SERS). Furthermore, it points the direction toward a multianalyte sensing platform. A mixed decanethiol/mercaptohexanol partition layer is used herein to demonstrate SERS lactate sensing. The reversibility of the sensor surface is characterized by exposing it alternately to aqueous lactate solutions and buffer without lactate. The partitioning and departitioning time constants were both found to be approximately 30 s. In addition, physiological lactate levels (i.e., 6-240 mg/dL) were quantified in phosphate-buffered saline medium using multivariate analysis with a root-mean-square error of prediction of 39.6 mg/dL. Finally, reversibility was tested for sequential glucose and lactate exposures. Complete partitioning and departitioning of both analytes was demonstrated.
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147
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Haes AJ, Zou S, Zhao J, Schatz GC, Van Duyne RP. Localized surface plasmon resonance spectroscopy near molecular resonances. J Am Chem Soc 2007; 128:10905-14. [PMID: 16910686 DOI: 10.1021/ja063575q] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The peak location of the localized surface plasmon resonance (LSPR) of noble metal nanoparticles is highly dependent upon the refractive index of the nanoparticles' surrounding environment. In this study, new phenomena are revealed by exploring the influence of interacting molecular resonances and nanoparticle resonances. The LSPR peak shift and line shape induced by a resonant molecule vary with wavelength. In most instances, the oscillatory dependence of the peak shift on wavelength tracks with the wavelength dependence of the real part of the refractive index, as determined by a Kramers-Kronig transformation of the molecular resonance absorption spectrum. A quantitative assessment of this shift based on discrete dipole approximation calculations shows that the Kramers-Kronig index must be scaled in order to match experiment.
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148
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Chan GH, Sherry LJ, Van Duyne RP, Ibers JA. Syntheses, Crystal Structures, and Optical and Magnetic Properties of Some CsLnCoQ
3
Compounds (Ln = Tm and Yb, Q = S; Ln = Ho and Yb, Q = Se). Z Anorg Allg Chem 2007. [DOI: 10.1002/zaac.200700179] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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149
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Haes AJ, Zhao J, Zou S, Own CS, Marks LD, Schatz GC, Van Duyne RP. Solution-phase, triangular ag nanotriangles fabricated by nanosphere lithography. J Phys Chem B 2007; 109:11158-62. [PMID: 16852361 DOI: 10.1021/jp051178g] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel method to produce solution-phase triangular silver nanoparticles is presented. Ag nanoparticles are prepared by nanosphere lithography and are subsequently released into solution. The resulting nanoparticles are asymmetrically functionalized to produce either single isolated nanoparticles or dimer pairs. The structural and optical properties of Ag nanoparticles have been characterized. Mie theory and the Discrete Dipole Approximation method (DDA) have been used to model and interpret the optical properties of the released Ag nanoparticles.
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150
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Zhao J, Jensen L, Sung J, Zou S, Schatz GC, Duyne RPV. Interaction of Plasmon and Molecular Resonances for Rhodamine 6G Adsorbed on Silver Nanoparticles. J Am Chem Soc 2007; 129:7647-56. [PMID: 17521187 DOI: 10.1021/ja0707106] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Localized surface plasmon resonance (LSPR) is a key optical property of metallic nanoparticles. The peak position of the LSPR for noble-metal nanoparticles is highly dependent upon the refractive index of the surrounding media and has therefore been used for chemical and biological sensing. In this work, we explore the influence of resonant adsorbates on the LSPR of bare Ag nanoparticles (lambda(max,bare)). Specifically, we study the effect of rhodamine 6G (R6G) adsorption on the nanoparticle plasmon resonance because of its importance in single-molecule surface-enhanced Raman spectroscopy (SMSERS). Understanding the coupling between the R6G molecular resonances and the nanoparticle plasmon resonances will provide further insights into the role of LSPR and molecular resonance in SMSERS. By tuning lambda(max,bare) through the visible wavelength region, the wavelength-dependent LSPR response of the Ag nanoparticles to R6G binding was monitored. Furthermore, the electronic transitions of R6G on Ag surface were studied by measuring the surface absorption spectrum of R6G on an Ag film. Surprisingly, three LSPR shift maxima are found, whereas the R6G absorption spectrum shows only two absorption features. Deconvolution of the R6G surface absorption spectra at different R6G concentrations indicates that R6G forms dimers on the metal surface. An electromagnetic model based on quasi-static (Gans) theory reveals that the LSPR shift features are associated with the absorption of R6G monomer and dimers. Electronic structure calculations of R6G under various conditions were performed to study the origin of the LSPR shift features. These calculations support the view that the R6G dimer formation is the most plausible cause for the complicated LSPR response. These findings show the extreme sensitivity of LSPR in elucidating the detailed electronic structure of a resonant adsorbate.
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