1
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Hemant, Rahman A, Sharma P, Shanavas A, Neelakandan PP. BODIPY directed one-dimensional self-assembly of gold nanorods. NANOSCALE 2024; 16:12127-12133. [PMID: 38832457 DOI: 10.1039/d4nr02161d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
The assembly of anisotropic nanomaterials into ordered structures is challenging. Nevertheless, such self-assembled systems are known to have novel physicochemical properties and the presence of a chromophore within the nanoparticle ensemble can enhance the optical properties through plasmon-molecule electronic coupling. Here, we report the end-to-end assembly of gold nanorods into micrometer-long chains using a linear diamino BODIPY derivative. The preferential binding affinity of the amino group and the steric bulkiness of BODIPY directed the longitudinal assembly of gold nanorods. As a result of the linear assembly, the BODIPY chromophores positioned themselves in the plasmonic hotspots, which resulted in efficient plasmon-molecule coupling, thereby imparting photothermal properties to the assembled nanorods. This work thus demonstrates a new approach for the linear assembly of gold nanorods resulting in a plasmon-molecule coupled system, and the synergy between self-assembly and electronic coupling resulted in an efficient system having potential biomedical applications.
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Affiliation(s)
- Hemant
- Institute of Nano Science and Technology, Knowledge City, Sector 81, Mohali 140306, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Atikur Rahman
- Institute of Nano Science and Technology, Knowledge City, Sector 81, Mohali 140306, India.
| | - Priyanka Sharma
- Institute of Nano Science and Technology, Knowledge City, Sector 81, Mohali 140306, India.
| | - Asifkhan Shanavas
- Institute of Nano Science and Technology, Knowledge City, Sector 81, Mohali 140306, India.
| | - Prakash P Neelakandan
- Institute of Nano Science and Technology, Knowledge City, Sector 81, Mohali 140306, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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2
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Lawson ZR, Preston AS, Korsa MT, Dominique NL, Tuff WJ, Sutter E, Camden JP, Adam J, Hughes RA, Neretina S. Plasmonic Gold Trimers and Dimers with Air-Filled Nanogaps. ACS APPLIED MATERIALS & INTERFACES 2022; 14:28186-28198. [PMID: 35695394 DOI: 10.1021/acsami.2c04800] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The subwavelength confinement of light energy in the nanogaps formed between adjacent plasmonic nanostructures provides the foundational basis for nanophotonic applications. Within this realm, air-filled nanogaps are of central importance because they present a cavity where application-specific nanoscale objects can reside. When forming such configurations on substrate surfaces, there is an inherent difficulty in that the most technologically relevant nanogap widths require closely spaced nanostructures separated by distances that are inaccessible through standard electron-beam lithography techniques. Herein, we demonstrate an assembly route for the fabrication of aligned plasmonic gold trimers with air-filled vertical nanogaps having widths that are defined with spatial controls that exceed those of lithographic processes. The devised procedure uses a sacrificial oxide layer to define the nanogap, a glancing angle deposition to impose a directionality on trimer formation, and a sacrificial antimony layer whose sublimation regulates the gold assembly process. By further implementing a benchtop nanoimprint lithography process and a glancing angle ion milling procedure as additional controls over the assembly, it is possible to deterministically position trimers in periodic arrays and extend the assembly process to dimer formation. The optical response of the structures, which is characterized using polarization-dependent spectroscopy, surface-enhanced Raman scattering, and refractive index sensitivity measurements, shows properties that are consistent with simulation. This work, hence, forwards the wafer-based processing techniques needed to form air-filled nanogaps and place plasmonic energy at site-specific locations.
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Affiliation(s)
- Zachary R Lawson
- College of Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Arin S Preston
- College of Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Matiyas T Korsa
- Computational Materials Group, SDU Centre for Photonics Engineering, Mads Clausen Institute, University of Southern Denmark, 5230 Odense, Denmark
| | - Nathaniel L Dominique
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Walker J Tuff
- College of Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Eli Sutter
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Jon P Camden
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Jost Adam
- Computational Materials Group, SDU Centre for Photonics Engineering, Mads Clausen Institute, University of Southern Denmark, 5230 Odense, Denmark
| | - Robert A Hughes
- College of Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Svetlana Neretina
- College of Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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3
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Inaba T, Takenaka Y, Kawabata Y, Kato T. Effect of the Crystallization Process of Surfactant Bilayer Lamellar Structures on the Elongation of High-Aspect-Ratio Gold Nanorods. J Phys Chem B 2019; 123:4776-4783. [PMID: 31038313 DOI: 10.1021/acs.jpcb.8b10897] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The growth mechanism of an "in-gel synthesis method", that is, the effects of composition and structure of the lamellar gel phase below the Krafft temperature of surfactant solutions on the growth of long gold nanorods, was investigated. We changed the alkyl chain length of surfactant molecules to investigate the effect of surfactant self-assembly on the elongation of gold nanorods systematically; eight mixed solutions of alkyltrimethylammonium bromide (C nTAB; n = 2-16; n = even) with C18TAB were used for investigation. The Krafft temperature, self-assembly of surfactant molecules, and the crystallization process of each mixture were observed by differential scanning calorimetry, wide-angle X-ray scattering, visual inspection, and small-angle X-ray scattering. Gold nanorods were synthesized in these eight surfactant mixtures. These observations demonstrated that when the surfactant Lβ phase sustains for a long time, the space of the water layer is also kept large enough for the seeds to take up Au ions bound to surfactant micelles. In this case, the seeds can form long nanorods between bilayers. We conclude that not only the stability of the lamellar gel phase but also co-existence of Au-ion carriers, that is, surfactant micelles, is essential for the elongation of long gold nanorods.
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Affiliation(s)
- Takamichi Inaba
- Department of Chemistry , Tokyo Metropolitan University , Hachioji , Tokyo 192-0397 , Japan
| | - Yoshiko Takenaka
- Research Institute for Sustainable Chemistry , National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba , Ibaraki 305-8565 , Japan
| | - Youhei Kawabata
- Department of Chemistry , Tokyo Metropolitan University , Hachioji , Tokyo 192-0397 , Japan
| | - Tadashi Kato
- Department of Chemistry , Tokyo Metropolitan University , Hachioji , Tokyo 192-0397 , Japan
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4
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Ziv A, Tzaguy A, Hazut O, Yochelis S, Yerushalmi R, Paltiel Y. Self-formed nanogap junctions for electronic detection and characterization of molecules and quantum dots. RSC Adv 2017. [DOI: 10.1039/c7ra04600f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Fabrication of self-forming nanojunction devices is demonstrated using positioning of nanofloret-like building blocks that bridge the gap between two large micron scale electrodes.
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Affiliation(s)
- Amir Ziv
- Department of Applied Physics
- The Hebrew University of Jerusalem
- 9190401 Israel
| | - Avra Tzaguy
- Institute of Chemistry
- The Center for Nanoscience and Nanotechnology
- The Hebrew University of Jerusalem
- Jerusalem
- Israel
| | - Ori Hazut
- Institute of Chemistry
- The Center for Nanoscience and Nanotechnology
- The Hebrew University of Jerusalem
- Jerusalem
- Israel
| | - Shira Yochelis
- Department of Applied Physics
- The Hebrew University of Jerusalem
- 9190401 Israel
| | - Roie Yerushalmi
- Institute of Chemistry
- The Center for Nanoscience and Nanotechnology
- The Hebrew University of Jerusalem
- Jerusalem
- Israel
| | - Yossi Paltiel
- Department of Applied Physics
- The Hebrew University of Jerusalem
- 9190401 Israel
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5
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Dubois V, Niklaus F, Stemme G. Design and fabrication of crack-junctions. MICROSYSTEMS & NANOENGINEERING 2017; 3:17042. [PMID: 31057876 PMCID: PMC6444981 DOI: 10.1038/micronano.2017.42] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 06/01/2017] [Accepted: 06/19/2017] [Indexed: 05/06/2023]
Abstract
Nanogap electrodes consist of pairs of electrically conducting tips that exhibit nanoscale gaps. They are building blocks for a variety of applications in quantum electronics, nanophotonics, plasmonics, nanopore sequencing, molecular electronics, and molecular sensing. Crack-junctions (CJs) constitute a new class of nanogap electrodes that are formed by controlled fracture of suspended bridge structures fabricated in an electrically conducting thin film under residual tensile stress. Key advantages of the CJ methodology over alternative technologies are that CJs can be fabricated with wafer-scale processes, and that the width of each individual nanogap can be precisely controlled in a range from <2 to >100 nm. While the realization of CJs has been demonstrated in initial experiments, the impact of the different design parameters on the resulting CJs has not yet been studied. Here we investigate the influence of design parameters such as the dimensions and shape of the notches, the length of the electrode-bridge and the design of the anchors, on the formation and propagation of cracks and on the resulting features of the CJs. We verify that the design criteria yields accurate prediction of crack formation in electrode-bridges featuring a beam width of 280 nm and beam lengths ranging from 1 to 1.8 μm. We further present design as well as experimental guidelines for the fabrication of CJs and propose an approach to initiate crack formation after release etching of the suspended electrode-bridge, thereby enabling the realization of CJs with pristine electrode surfaces.
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Affiliation(s)
- Valentin Dubois
- KTH Royal Institute of Technology, Micro and Nanosystem, Osquldas väg 10, Stockholm 100 44, Sweden
| | - Frank Niklaus
- KTH Royal Institute of Technology, Micro and Nanosystem, Osquldas väg 10, Stockholm 100 44, Sweden
| | - Göran Stemme
- KTH Royal Institute of Technology, Micro and Nanosystem, Osquldas väg 10, Stockholm 100 44, Sweden
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6
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Dubois V, Niklaus F, Stemme G. Crack-Defined Electronic Nanogaps. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:2178-82. [PMID: 26784270 DOI: 10.1002/adma.201504569] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 12/03/2015] [Indexed: 05/24/2023]
Abstract
Achieving near-atomic-scale electronic nanogaps in a reliable and scalable manner will facilitate fundamental advances in molecular detection, plasmonics, and nanoelectronics. Here, a method is shown for realizing crack-defined nanogaps separating TiN electrodes, allowing parallel and scalable fabrication of arrays of sub-10 nm electronic nanogaps featuring individually defined gap widths.
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Affiliation(s)
- Valentin Dubois
- Department of Micro and Nanosystems, School of Electrical Engineering, KTH Royal Institute of Technology, SE-10044, Stockholm, Sweden
| | - Frank Niklaus
- Department of Micro and Nanosystems, School of Electrical Engineering, KTH Royal Institute of Technology, SE-10044, Stockholm, Sweden
| | - Göran Stemme
- Department of Micro and Nanosystems, School of Electrical Engineering, KTH Royal Institute of Technology, SE-10044, Stockholm, Sweden
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7
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Ngo HM, Lai ND, Ledoux-Rak I. High second-order nonlinear response of platinum nanoflowers: the role of surface corrugation. NANOSCALE 2016; 8:3489-3495. [PMID: 26795722 DOI: 10.1039/c5nr07571h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Platinum nanoflowers (PtNFs) were elaborated using the seed-mediated growth technique applied to monodisperse platinum nanoparticles (∼3.0 nm) synthesized by the chemical reduction method. The X-ray diffraction pattern confirmed the formation of face-centered-cubic platinum nanocrystals. We report the Harmonic Light Scattering (HLS) properties of PtNFs for six different diameters (∼7.0; 8.0; 10.0; 14.0; 20.0 and 31.0 nm). From these HLS data we infer, for the first time, large hyperpolarizability β values of PtNFs. These very high β values of PtNFs are assigned mainly to highly corrugated surfaces for nanoparticles with irregular shapes.
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Affiliation(s)
- Hoang Minh Ngo
- Laboratoire de Photonique Quantique et Moléculaire, UMR 8537, Ecole Normale Supérieure de Cachan, CentraleSupélec, CNRS, Université Paris-Saclay, 94235 Cachan, France.
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8
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Ahmad I, Jansen HP, Zandvliet HJW, Kooij ES. Hydrodynamic confinement and capillary alignment of gold nanorods. NANOTECHNOLOGY 2016; 27:025301. [PMID: 26630013 DOI: 10.1088/0957-4484/27/2/025301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Controlling the alignment and orientation of nanorods on various surfaces poses major challenges. In this work, we investigate hydrodynamic confinement and capillary alignment of gold nanorod assembly on chemically stripe-patterned substrates. The surface patterns consist of alternating hydrophilic and hydrophobic micrometer wide stripes; a macroscopic wettability gradient enables controlling the dynamics of deposited suspension droplets. We show that drying of residual liquid on the hydrophilic stripes gives rise to spatially localized deposition and alignment of the nanorods. Moreover, a universal relation between the extent of order within the single layers of nanoparticles and the lateral dimension of the deposits is presented and discussed.
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Affiliation(s)
- Imtiaz Ahmad
- Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, NL-7500AE Enschede, The Netherlands
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9
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Ngo HM, Nguyen PP, Ledoux-Rak I. Optimization of second harmonic generation of gold nanospheres and nanorods in aqueous solution: the dominant role of surface area. Phys Chem Chem Phys 2016; 18:3352-6. [DOI: 10.1039/c5cp06850a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gold nanoparticles display exceptionally strong β values. We demonstrated that the first hyperpolarizability (β) strongly depends on surface area of gold nanoparticles.
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Affiliation(s)
- Hoang Minh Ngo
- Laboratoire de Photonique Quantique et Moléculaire
- UMR 8537
- Ecole Normale Supérieure de Cachan
- CentraleSupélec
- CNRS
| | - Phuong Phong Nguyen
- Department of Chemistry
- University of Science
- Vietnam National University
- Ho Chi Minh City
- Vietnam
| | - Isabelle Ledoux-Rak
- Laboratoire de Photonique Quantique et Moléculaire
- UMR 8537
- Ecole Normale Supérieure de Cachan
- CentraleSupélec
- CNRS
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10
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Cui A, Dong H, Hu W. Nanogap Electrodes towards Solid State Single-Molecule Transistors. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:6115-6141. [PMID: 26450402 DOI: 10.1002/smll.201501283] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 07/23/2015] [Indexed: 06/05/2023]
Abstract
With the establishment of complementary metal-oxide-semiconductor (CMOS)-based integrated circuit technology, it has become more difficult to follow Moore's law to further downscale the size of electronic components. Devices based on various nanostructures were constructed to continue the trend in the minimization of electronics, and molecular devices are among the most promising candidates. Compared with other candidates, molecular devices show unique superiorities, and intensive studies on molecular devices have been carried out both experimentally and theoretically at the present time. Compared to two-terminal molecular devices, three-terminal devices, namely single-molecule transistors, show unique advantages both in fundamental research and application and are considered to be an essential part of integrated circuits based on molecular devices. However, it is very difficult to construct them using the traditional microfabrication techniques directly, thus new fabrication strategies are developed. This review aims to provide an exclusive way of manufacturing solid state gated nanogap electrodes, the foundation of constructing transistors of single or a few molecules. Such single-molecule transistors have the potential to be used to build integrated circuits.
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Affiliation(s)
- Ajuan Cui
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Huanli Dong
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Wenping Hu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, PR China
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11
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Cui A, Liu Z, Dong H, Wang Y, Zhen Y, Li W, Li J, Gu C, Hu W. Single grain boundary break junction for suspended nanogap electrodes with gapwidth down to 1-2 nm by focused ion beam milling. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:3002-6. [PMID: 25854513 DOI: 10.1002/adma.201500527] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 03/17/2015] [Indexed: 05/21/2023]
Abstract
Single grain boundary junctions are used for the fabrication of suspended nanogap electrodes with a gapwidth down to 1-2 nm through the break of such junctions by focused ion beam (FIB) milling. With advantages of stability and no debris, such nanogap electrodes are suitable for single molecular electronic device construction.
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Affiliation(s)
- Ajuan Cui
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Zhe Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Huanli Dong
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Yujin Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Yonggang Zhen
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Wuxia Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Junjie Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Changzhi Gu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Wenping Hu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) & Department of Chemistry, School of Science, Tianjin University, Tianjin, 300072, China
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12
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Takenaka Y. One-pot synthesis of long twin gold nanorods in a gelled surfactant solution. RSC Adv 2015. [DOI: 10.1039/c4ra17031h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A new one-pot synthesis method was developed for producing long twin gold nanorods with lengths of ca. 1755 nm, which have the potential to be arranged on a substrate using anisotropic surface modification.
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Affiliation(s)
- Y. Takenaka
- Nanosystem Research Institute
- National Institute of Advanced Industrial Science and Technology
- Tsukuba 305-8565
- Japan
- PRESTO
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13
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Sachser R, Reith H, Huzel D, Winhold M, Huth M. Catalytic Purification of Directly Written Nanostructured Pt Microelectrodes. ACS APPLIED MATERIALS & INTERFACES 2014; 6:15868-74. [PMID: 25111450 DOI: 10.1021/am503407y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Affiliation(s)
- Roland Sachser
- Physikalisches
Institut, Goethe-Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany
| | - Heiko Reith
- Physikalisches
Institut, Goethe-Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany
- Institute
for Microtechnologies (IMtech), RheinMain University of Applied Sciences, Am Brückweg 26, 65428 Rüsselsheim, Germany
| | - Daniel Huzel
- Physikalisches
Institut, Goethe-Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany
| | - Marcel Winhold
- Physikalisches
Institut, Goethe-Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany
| | - Michael Huth
- Physikalisches
Institut, Goethe-Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany
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14
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Jain T, Tang Q, Bjørnholm T, Nørgaard K. Wet chemical synthesis of soluble gold nanogaps. Acc Chem Res 2014; 47:2-11. [PMID: 23944385 DOI: 10.1021/ar3002848] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A central challenge in molecular electronics is to create electrode pairs separated by only a few nanometers that can accommodate a single molecule of interest to be optically or electrically characterized while residing in the gap. Current techniques for nanogap fabrication are largely based on top-down approaches and often rely on subsequent deposition of molecules into the nanogap. In such an approach, the molecule may bridge the gap differently with each experiment due to variations at the metal-molecule interface. Conversely, chemists can readily synthesize gold nanorods (AuNRs) in aqueous solution. Through controlled end-to-end assembly of the AuNRs into dimers or chains, facilitated via target molecules, they can be used as electrical contacts. In this way, the preparation of AuNR-molecule-AuNR junctions by wet chemical methods may afford a large number of identical devices with little variation in the interface between molecule and electrode (AuNR). In this Account, we highlight recent progress in using chemically synthesized AuNRs as building blocks for molecular electronic applications. We outline the general synthesis and properties of AuNRs and describe the aqueous growth of dimeric AuNR structures from an insulating molecule linked to AuNR precursors (gold seeds). Conjugated, electronically active molecules are typically not soluble under the conditions required for the bottom-up growth of AuNRs. Therefore, we present a strategy that utilizes host-guest chemistry in order to make such π-systems compatible with the AuNR growth procedure. In order to electrically characterize the AuNR-molecule-AuNR constructs, we must transfer them onto a substrate and contact external electrodes. We discuss the implications of using electron-beam lithography for making this contact. In addition, we introduce a novel fabrication approach in which we can grow AuNR nanogap electrodes in situ on prepatterned substrates, thus circumventing post-processing steps that potentially damage the nanogap environment. Due to the inherent optical properties of AuNRs, electromagnetic field enhancement in the nanogaps lets us spectroscopically characterize the molecules via surface-enhanced Raman scattering. We discuss the incorporation of oligopeptides functionalized with acetylene units having uniquely identifiable vibrational modes. This acetylene moiety allows chemical reactions to be performed in the gaps via click chemistry, and the oligopeptide linking platform opens for integration of larger biological components.
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Affiliation(s)
- Titoo Jain
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Qingxin Tang
- School of Physics, Northeast Normal University, 5268 Renmin Street, Changchun, Jilin Province, People’s Republic of China
| | - Thomas Bjørnholm
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Kasper Nørgaard
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
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15
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Sun L, Diaz-Fernandez YA, Gschneidtner TA, Westerlund F, Lara-Avila S, Moth-Poulsen K. Single-molecule electronics: from chemical design to functional devices. Chem Soc Rev 2014; 43:7378-411. [DOI: 10.1039/c4cs00143e] [Citation(s) in RCA: 361] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The use of single molecules in electronics represents the next limit of miniaturisation of electronic devices, which would enable to continue the trend of aggressive downscaling of silicon-based electronic devices.
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Affiliation(s)
- Lanlan Sun
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Yuri A. Diaz-Fernandez
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Tina A. Gschneidtner
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Fredrik Westerlund
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Samuel Lara-Avila
- Department of Micro and Nanotechnology
- MC2
- Chalmers University of Technology
- , Sweden
| | - Kasper Moth-Poulsen
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
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16
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Effects of surfactant concentration on formation of high-aspect-ratio gold nanorods. J Colloid Interface Sci 2013; 407:265-72. [PMID: 23830281 DOI: 10.1016/j.jcis.2013.06.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 05/13/2013] [Accepted: 06/05/2013] [Indexed: 11/22/2022]
Abstract
The effects of surfactant concentration in a growth solution on the elongation of gold nanorods were examined. Gold nanorods were synthesized in solutions with different concentrations of hexadecyltrimethylammonium bromide (HTAB): 100, 200, 300, 400, 500, and 600 mM. The nanorods grown in a solution with higher surfactant concentrations were longer (aspect ratio ~30) than those grown in that with lower concentrations (aspect ratio <10). The self-assembled surfactant structures in the solutions were analyzed using viscosity measurement and small-angle X-ray scattering. These results showed a decrease in the inter-micellar distance with increasing surfactant concentration. Taking the chemical equilibrium for the complex formation between Au ions and HTAB micelles into account, we found that the free Au ion concentration decreases accompanied with the increase in the surfactant concentration. This decrease in the free Au ion concentration suppresses undesirable secondary nucleation of gold crystals in a growth solution, resulting in gold nanorod elongation.
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17
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Chen T, Pourmand M, Feizpour A, Cushman B, Reinhard BM. Tailoring Plasmon Coupling in Self-Assembled One-Dimensional Au Nanoparticle Chains through Simultaneous Control of Size and Gap Separation. J Phys Chem Lett 2013; 4:2147-2152. [PMID: 24027605 PMCID: PMC3766581 DOI: 10.1021/jz401066g] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We investigated the near- and far-field response of one-dimensional chains of Au nanoparticles (NPs) fabricated with high structural control through template guided self-assembly. We demonstrate that the density of polyethylene glycol (PEG) ligands grafted onto the NP surface, in combination with the buffer conditions, facilitate a systematic variation of the average gap width (g) at short separations of g<1.1nm. The overall size (n) of the cluster was controlled through the template. The ability to independently vary n and g allowed for a rational tuning of the spectral response in individual NP clusters over a broad spectral range. We used this structural control for a systematic investigation of the electromagnetic coupling underlying the superradiant cluster mode. Independent of the chain length, plasmon coupling is dominated by direct neighbor interactions. A decrease in coupling strength at separations ≲0.5nm indicates the presence of non-local and/or quantum mechanical coupling mechanisms.
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Affiliation(s)
- Tianhong Chen
- Department of Chemistry and the Photonics Center, Boston University, Boston, MA 02215, United States
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18
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Affiliation(s)
- Emanuel Lörtscher
- IBM Research-Zurich Laboratory, Science & Technology Department, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland.
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19
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Mai Y, Xiao L, Eisenberg A. Morphological Control in Aggregates of Amphiphilic Cylindrical Metal–Polymer “Brushes”. Macromolecules 2013. [DOI: 10.1021/ma400236g] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Yiyong Mai
- School of Chemistry and Chemical
Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, 200240 Shanghai, P. R. China
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal,
Quebec H3A 2K6, Canada
| | - Lin Xiao
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal,
Quebec H3A 2K6, Canada
| | - Adi Eisenberg
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal,
Quebec H3A 2K6, Canada
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20
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Vigderman L, Khanal BP, Zubarev ER. Functional gold nanorods: synthesis, self-assembly, and sensing applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:4811-41, 5014. [PMID: 22740090 DOI: 10.1002/adma.201201690] [Citation(s) in RCA: 445] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Indexed: 05/19/2023]
Abstract
Gold nanorods have received much attention due to their unique optical and electronic properties which are dependent on their shape, size, and aspect ratio. This article covers in detail the synthesis, functionalization, self-assembly, and sensing applications of gold nanorods. The synthesis of three major types of rods is discussed: single-crystalline and pentahedrally-twinned rods, which are synthesized by wet chemistry methods, and polycrystalline rods, which are synthesized by templated deposition. Functionalization of these rods is usually necessary for their applications, but can often be problematic due to their surfactant coating. Thus, general strategies are provided for the covalent and noncovalent functionalization of gold nanorods. The review will then examine the significant progress that has been made in controllable assembly of nanorods into various arrangements. This assembly can have a large effect on measurable properties of rods, making it particularly applicable towards sensing of a variety of analytes. Other types of sensing not dependent on nanorod assembly, such as refractive-index based sensing, are also discussed.
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Affiliation(s)
- Leonid Vigderman
- Department of Chemistry, Rice University, 6100 Main Street, Houston, TX 77005, USA
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21
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End-to-end assembly of gold nanorods via oligopeptide linking and surfactant control. J Colloid Interface Sci 2012; 376:83-90. [DOI: 10.1016/j.jcis.2012.03.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 03/08/2012] [Accepted: 03/09/2012] [Indexed: 11/21/2022]
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22
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Jain T, Lara-Avila S, Kervennic YV, Moth-Poulsen K, Nørgaard K, Kubatkin S, Bjørnholm T. Aligned growth of gold nanorods in PMMA channels: parallel preparation of nanogaps. ACS NANO 2012; 6:3861-3867. [PMID: 22494354 DOI: 10.1021/nn204986y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We demonstrate alignment and positional control of gold nanorods grown in situ on substrates using a seed-mediated synthetic approach. Alignment control is obtained by directing the growth of spherical nanoparticle seeds into nanorods in well-defined poly(methyl methacrylate) nanochannels. Substrates with prepatterned metallic electrodes provide an additional handle for the position of the gold nanorods and yield nanometer-sized gaps between the electrode and nanorod. The presented approach is a novel demonstration of bottom-up device fabrication of multiple nanogap junctions on a single chip mediated viain situ growth of gold nanorods acting as nanoelectrodes.
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Affiliation(s)
- Titoo Jain
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100, Copenhagen Ø, Denmark
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23
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Jiang L, Dong H, Meng Q, Tan J, Jiang W, Xu C, Wang Z, Hu W. Molecular crystal lithography: a facile and low-cost approach to fabricate nanogap electrodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:694-698. [PMID: 22038893 DOI: 10.1002/adma.201103098] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 09/23/2011] [Indexed: 05/31/2023]
Abstract
A novel cost-efficient and facile technique, molecular crystal lithography, to fabricate nanogap electrodes efficiently is reported. The gap width of the electrodes can be tuned from ∼9 nm to several micrometers. Organic field-effect transistors based on the nanogap electrodes all exhibit a high performance, indicating the effectiveness and practicability of molecular crystal lithography for mass production of nanogap electrodes.
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Affiliation(s)
- Lang Jiang
- Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190, PR China
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24
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Biagioni P, Huang JS, Hecht B. Nanoantennas for visible and infrared radiation. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2012; 75:024402. [PMID: 22790344 DOI: 10.1088/0034-4885/75/2/024402] [Citation(s) in RCA: 263] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Nanoantennas for visible and infrared radiation can strongly enhance the interaction of light with nanoscale matter by their ability to efficiently link propagating and spatially localized optical fields. This ability unlocks an enormous potential for applications ranging from nanoscale optical microscopy and spectroscopy over solar energy conversion, integrated optical nanocircuitry, opto-electronics and density-of-states engineering to ultra-sensing as well as enhancement of optical nonlinearities. Here we review the current understanding of metallic optical antennas based on the background of both well-developed radiowave antenna engineering and plasmonics. In particular, we discuss the role of plasmonic resonances on the performance of nanoantennas and address the influence of geometrical parameters imposed by nanofabrication. Finally, we give a brief account of the current status of the field and the major established and emerging lines of investigation in this vivid area of research.
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Affiliation(s)
- Paolo Biagioni
- CNISM-Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
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25
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Konev AS, Khlebnikov AF, Frauendorf H. Bisaziridine Tetracarboxylates as Building Blocks in the Stereoselective Synthesis of C60-Fullerene Diads and Dumbbell-like Bis-C60-fullerene Triads. J Org Chem 2011; 76:6218-29. [DOI: 10.1021/jo2009627] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alexander S. Konev
- Department of Chemistry, Saint Petersburg State University, Universitetskii
pr. 26, 198504 St. Petersburg, Russia
| | - Alexander F. Khlebnikov
- Department of Chemistry, Saint Petersburg State University, Universitetskii
pr. 26, 198504 St. Petersburg, Russia
| | - Holm Frauendorf
- Institute of Organic and Biomolecular Chemistry of Georg-August-University, Tammannstrasse 2, D37077 Göttingen, Germany
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26
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Kuemin C, Stutz R, Spencer ND, Wolf H. Precise placement of gold nanorods by capillary assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:6305-6310. [PMID: 21491863 DOI: 10.1021/la2001128] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Capillary assembly was explored for the precise placement of 25 nm × 70 nm colloidal gold nanorods on prestructured poly(dimethylsiloxane) template surfaces. The concentration of nanorods and cationic surfactant cetyltrimethylammonium bromide (CTAB), the template wettability, and most critically the convective transport of the dispersed nanorods were tuned to study their effect on the resulting assembly yield. It is shown that gold nanorods can be placed into arrayed 120-nm diameter holes, achieving assembly yields as high as 95% when the local concentration of nanorods at the receding contact line is sufficiently high. Regular arrays of gold nanorods have several benefits over randomly deposited nanorod arrangements. Each assembled nanorod resides at a precisely defined location and can easily be found for subsequent characterization or direct utilization in a device. The former is illustrated by collecting scattering spectra from single nanorods and nanorod dimers, followed by subsequent SEM characterization without the need for intricate registration schemes.
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Affiliation(s)
- Cyrill Kuemin
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
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27
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Song H, Reed MA, Lee T. Single molecule electronic devices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:1583-1608. [PMID: 21290434 DOI: 10.1002/adma.201004291] [Citation(s) in RCA: 256] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2010] [Indexed: 05/30/2023]
Abstract
Single molecule electronic devices in which individual molecules are utilized as active electronic components constitute a promising approach for the ultimate miniaturization and integration of electronic devices in nanotechnology through the bottom-up strategy. Thus, the ability to understand, control, and exploit charge transport at the level of single molecules has become a long-standing desire of scientists and engineers from different disciplines for various potential device applications. Indeed, a study on charge transport through single molecules attached to metallic electrodes is a very challenging task, but rapid advances have been made in recent years. This review article focuses on experimental aspects of electronic devices made with single molecules, with a primary focus on the characterization and manipulation of charge transport in this regime.
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Affiliation(s)
- Hyunwook Song
- Department of Materials Science and Engineering, Department of Nanobio Materials and Electronics, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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28
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Romo-Herrera JM, Alvarez-Puebla RA, Liz-Marzán LM. Controlled assembly of plasmonic colloidal nanoparticle clusters. NANOSCALE 2011; 3:1304-15. [PMID: 21229160 DOI: 10.1039/c0nr00804d] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Coupling of localized surface plasmon resonances results in singular effects at the void space between noble metal nanoparticles. However, implementation of practical applications based on plasmon coupling calls for the high yield production of metal nanoparticle clusters (dimers, trimers, tetramers, …) with small gaps. Therefore, controlled assembly using colloid chemistry methods is an emerging and promising field. We present a brief overview over the controlled assembly of plasmonic nanoparticle clusters by colloid chemistry methods, together with a description of their plasmonic properties and some applications, with an emphasis in sensing through surface-enhanced Raman scattering spectroscopy for bio-detection purposes. We point out the important role of separation methods to obtain colloidal clusters in high yield. A special encouragement to explore assembly of anisotropic building blocks is pursued.
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Affiliation(s)
- José M Romo-Herrera
- Departamento de Química Física and Unidad Asociada CSIC, Universidade de Vigo, 36310, Vigo, Spain.
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29
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Gold nanorod crystal growth: From seed-mediated synthesis to nanoscale sculpting. Curr Opin Colloid Interface Sci 2011. [DOI: 10.1016/j.cocis.2011.01.001] [Citation(s) in RCA: 199] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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30
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Lee JK, Jung YH, Tok JBH, Bao Z. Syntheses of organic molecule-DNA hybrid structures. ACS NANO 2011; 5:2067-74. [PMID: 21323343 DOI: 10.1021/nn1032455] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Investigation of robust and efficient pathways to build DNA-organic molecule hybrid structures is fundamentally important to realize controlled placement of single molecules for potential applications, such as single-molecule electronic devices. Herein, we report a systematic investigation of synthetic processes for preparing organic molecule-DNA building blocks and their subsequent elongation to generate precise micrometer-sized structures. Specifically, optimal cross-coupling routes were identified to enable chemical linkages between three different organic molecules, namely, polyethylene glycol (PEG), poly(p-phenylene ethynylene) (PPE), and benzenetricarboxylate, with single-stranded (ss) DNA. The resulting DNA-organic molecule hybrid building blocks were purified and characterized by both denaturing gel electrophoresis and electrospray ionization mass spectrometry (ESI-MS). The building blocks were subsequently elongated through both the DNA hybridization and ligation processes to prepare micrometer-sized double-stranded (ds) DNA-organic molecule hybrid structures. The described synthetic procedures should facilitate future syntheses of various hybrid DNA-based organic molecular structures.
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Affiliation(s)
- Jungkyu K Lee
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
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31
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Das AK, Raj CR. Rapid room temperature synthesis of electrocatalytically active Au nanostructures. J Colloid Interface Sci 2011; 353:506-11. [DOI: 10.1016/j.jcis.2010.09.080] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 09/07/2010] [Accepted: 09/25/2010] [Indexed: 11/29/2022]
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32
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Zhong L, Zhou X, Bao S, Shi Y, Wang Y, Hong S, Huang Y, Wang X, Xie Z, Zhang Q. Rational design and SERS properties of side-by-side, end-to-end and end-to-side assemblies of Au nanorods. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm11193k] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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33
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Petersen AB, Thyrhaug E, Jain T, Kilsaa K, Bols M, Moth-Poulsen K, Harrit N, Bjørnholm T. First Step in Chemical Preparation of Metal Nanogaps Bridged by Thiol End-Capped Molecular Wires. J Phys Chem B 2010; 114:11771-7. [DOI: 10.1021/jp105948v] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Asger B. Petersen
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Erling Thyrhaug
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Titoo Jain
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Kristine Kilsaa
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Mikael Bols
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Kasper Moth-Poulsen
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Niels Harrit
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Thomas Bjørnholm
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
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34
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Zhu J, Yong KT, Roy I, Hu R, Ding H, Zhao L, Swihart MT, He GS, Cui Y, Prasad PN. Additive controlled synthesis of gold nanorods (GNRs) for two-photon luminescence imaging of cancer cells. NANOTECHNOLOGY 2010; 21:285106. [PMID: 20585168 DOI: 10.1088/0957-4484/21/28/285106] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Gold nanorods (GNRs) with a longitudinal surface plasmon resonance peak that is tunable from 600 to 1100 nm have been fabricated in a cetyl trimethylammoniumbromide (CTAB) micellar medium using hydrochloric acid and silver nitrate as additives to control their shape and size. By manipulating the concentrations of silver nitrate and hydrochloric acid, the aspect ratio of the GNRs was reliably and reproducibly tuned from 2.5 to 8. The GNRs were first coated with polyelectrolyte multilayers and then bioconjugated to transferrin (Tf) to target pancreatic cancer cells. Two-photon imaging excited from the bioconjugated GNRs demonstrated receptor-mediated uptake of the bioconjugates into Panc-1 cells, overexpressing the transferrin receptor (TfR). The bioconjugated GNR formulation exhibited very low toxicity, suggesting that it is biocompatible and potentially suitable for targeted two-photon bioimaging.
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Affiliation(s)
- Jing Zhu
- Institute for Lasers, Photonics and Biophotonics, University at Buffalo, The State University of New York, Buffalo, NY 14260-4200, USA
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35
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Abstract
Nanogap electrodes (namely, a pair of electrodes with a nanometer gap) are fundamental building blocks for the fabrication of nanometer-sized devices and circuits. They are also important tools for the examination of material properties at the nanometer scale, even at the molecular scale. In this review, the techniques for the fabrication of nanogap electrodes, the preparation of assembled devices based on the nanogap electrodes, and the potential application of these nanodevices for analysis of material properties are introduced. The history, the research status, and the prospects of nanogap electrodes are also discussed.
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Affiliation(s)
- Tao Li
- Beijing National Laboratory, Institute of Chemistry Chinese Academy of Sciences, Beijing 100190, PR China.
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36
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Moth-Poulsen K, Bjørnholm T. Molecular electronics with single molecules in solid-state devices. NATURE NANOTECHNOLOGY 2009; 4:551-6. [PMID: 19734925 DOI: 10.1038/nnano.2009.176] [Citation(s) in RCA: 226] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The ultimate aim of molecular electronics is to understand and master single-molecule devices. Based on the latest results on electron transport in single molecules in solid-state devices, we focus here on new insights into the influence of metal electrodes on the energy spectrum of the molecule, and on how the electron transport properties of the molecule depend on the strength of the electronic coupling between it and the electrodes. A variety of phenomena are observed depending on whether this coupling is weak, intermediate or strong.
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Affiliation(s)
- Kasper Moth-Poulsen
- Nano-Science Center & Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen, Denmark
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