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Abstract
Terahertz time-domain spectroscopy (THz-TDS) is a non-invasive, non-contact and label-free technique for biological and chemical sensing as THz-spectra are less energetic and lie in the characteristic vibration frequency regime of proteins and DNA molecules. However, THz-TDS is less sensitive for the detection of micro-organisms of size equal to or less than λ/100 (where, λ is the wavelength of the incident THz wave), and molecules in extremely low concentration solutions (like, a few femtomolar). After successful high-throughput fabrication of nanostructures, nanoantennas were found to be indispensable in enhancing the sensitivity of conventional THz-TDS. These nanostructures lead to strong THz field enhancement when in resonance with the absorption spectrum of absorptive molecules, causing significant changes in the magnitude of the transmission spectrum, therefore, enhancing the sensitivity and allowing the detection of molecules and biomaterials in extremely low concentration solutions. Herein, we review the recent developments in ultra-sensitive and selective nanogap biosensors. We have also provided an in-depth review of various high-throughput nanofabrication techniques. We also discussed the physics behind the field enhancements in the sub-skin depth as well as sub-nanometer sized nanogaps. We introduce finite-difference time-domain (FDTD) and molecular dynamics (MD) simulation tools to study THz biomolecular interactions. Finally, we provide a comprehensive account of nanoantenna enhanced sensing of viruses (like, H1N1) and biomolecules such as artificial sweeteners which are addictive and carcinogenic.
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Affiliation(s)
- Subham Adak
- Department of Physics, Birla Institute of Technology, Mesra, Ranchi - 835215, Jharkhand, India.
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Rubio-Lara JA, Bergler F, Attwood SJ, Edwardson JM, Welland ME. Ultraflat Gold QCM Electrodes Fabricated with Pressure-Forming Template Stripping for Protein Studies at the Nanoscale. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:8889-8895. [PMID: 30857390 DOI: 10.1021/acs.langmuir.8b03782] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Single-molecule imaging of proteins using atomic force microscopy (AFM) is crucially dependent on protein attachment to ultraflat substrates. The template-stripping (TS) technique, which can be used to create large areas of atomically flat gold, has been used to great effect for this purpose. However, this approach requires an epoxy, which can swell in solution, causing surface roughening and substantially increasing the thickness of any sample, preventing its use on acoustic resonators in liquid. Diffusion bonding techniques should circumvent this problem but cannot be used on samples containing patterned features with mismatched heights because of cracking and poor transfer. Here, we describe a new technique called pressure-forming TS (PTS), which permits an ultraflat (0.35 ± 0.05 nm root-mean-square roughness) layer of gold to be transferred to the surface of a patterned substrate at low temperature and pressure. We demonstrate this technique by modifying a quartz crystal microbalance (QCM) sensor to contain an ultraflat gold surface. Standard QCM chips have substantial roughness, preventing AFM imaging of proteins on the surface after measurement. With our approach, there is no need to run samples in parallel: the modified QCM chip is flat enough to permit high-contrast AFM imaging after adsorption studies have been conducted. The PTS-QCM chips are then used to demonstrate adsorption of bovine serum albumin in comparison to rough QCM chips. The ability to attach thin layers of ultraflat metals to surfaces of heterogeneous nature without epoxy will have many applications in diverse fields where there is a requirement to observe nanoscale phenomena with multiple techniques, including surface and interfacial science, optics, and biosensing.
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Affiliation(s)
- Juan A Rubio-Lara
- Nanoscience Centre , University of Cambridge , 11 JJ Thomson Avenue , Cambridge CB3 0FF , U.K
| | - Frederik Bergler
- Department of Pharmacology , University of Cambridge , Tennis Court Road , Cambridge CB2 1PD , U.K
| | - Simon J Attwood
- Nanoscience Centre , University of Cambridge , 11 JJ Thomson Avenue , Cambridge CB3 0FF , U.K
| | - J Michael Edwardson
- Department of Pharmacology , University of Cambridge , Tennis Court Road , Cambridge CB2 1PD , U.K
| | - Mark E Welland
- Nanoscience Centre , University of Cambridge , 11 JJ Thomson Avenue , Cambridge CB3 0FF , U.K
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Baumberg JJ, Aizpurua J, Mikkelsen MH, Smith DR. Extreme nanophotonics from ultrathin metallic gaps. NATURE MATERIALS 2019; 18:668-678. [PMID: 30936482 DOI: 10.1038/s41563-019-0290-y] [Citation(s) in RCA: 256] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 01/16/2019] [Indexed: 05/18/2023]
Abstract
Ultrathin dielectric gaps between metals can trap plasmonic optical modes with surprisingly low loss and with volumes below 1 nm3. We review the origin and subtle properties of these modes, and show how they can be well accounted for by simple models. Particularly important is the mixing between radiating antennas and confined nanogap modes, which is extremely sensitive to precise nanogeometry, right down to the single-atom level. Coupling nanogap plasmons to electronic and vibronic transitions yields a host of phenomena including single-molecule strong coupling and molecular optomechanics, opening access to atomic-scale chemistry and materials science, as well as quantum metamaterials. Ultimate low-energy devices such as robust bottom-up assembled single-atom switches are thus in prospect.
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Affiliation(s)
- Jeremy J Baumberg
- NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| | - Javier Aizpurua
- Materials Physics Center CSIC-UPV/EHU and Donostia International Physics Center DIPC, Paseo Manuel de Lardizabal, Donostia-San Sebastiàn, Spain
| | - Maiken H Mikkelsen
- Center for Metamaterials and Integrated Plasmonics, Duke University, Durham, NC, USA
| | - David R Smith
- Center for Metamaterials and Integrated Plasmonics, Duke University, Durham, NC, USA
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54
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Zheng X, Kupresak M, Verellen N, Moshchalkov VV, Vandenbosch GAE. A Review on the Application of Integral Equation‐Based Computational Methods to Scattering Problems in Plasmonics. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201900087] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Xuezhi Zheng
- Department of Electrical Engineering (ESAT), the TELEMIC GroupKU Leuven Kasteelpark Arenberg 10, BUS 2444 Leuven B‐3001 Belgium
| | - Mario Kupresak
- Department of Electrical Engineering (ESAT), the TELEMIC GroupKU Leuven Kasteelpark Arenberg 10, BUS 2444 Leuven B‐3001 Belgium
| | - Niels Verellen
- Life Science Technologies and Integrated PhotonicsIMEC Kapeldreef 75 Leuven B‐3001 Belgium
| | - Victor V. Moshchalkov
- Nanoscale Superconductivity and MagnetismKU Leuven Celestijnenlaan 200D, BUS 2414 Leuven B‐3001 Belgium
| | - Guy A. E. Vandenbosch
- Department of Electrical Engineering (ESAT), the TELEMIC GroupKU Leuven Kasteelpark Arenberg 10, BUS 2444 Leuven B‐3001 Belgium
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55
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Peng J, Jeong HH, Lin Q, Cormier S, Liang HL, De Volder MFL, Vignolini S, Baumberg JJ. Scalable electrochromic nanopixels using plasmonics. SCIENCE ADVANCES 2019; 5:eaaw2205. [PMID: 31093530 PMCID: PMC6510554 DOI: 10.1126/sciadv.aaw2205] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 03/27/2019] [Indexed: 05/21/2023]
Abstract
Plasmonic metasurfaces are a promising route for flat panel display applications due to their full color gamut and high spatial resolution. However, this plasmonic coloration cannot be readily tuned and requires expensive lithographic techniques. Here, we present scalable electrically driven color-changing metasurfaces constructed using a bottom-up solution process that controls the crucial plasmonic gaps and fills them with an active medium. Electrochromic nanoparticles are coated onto a metallic mirror, providing the smallest-area active plasmonic pixels to date. These nanopixels show strong scattering colors and are electrically tunable across >100-nm wavelength ranges. Their bistable behavior (with persistence times exceeding hundreds of seconds) and ultralow energy consumption (9 fJ per pixel) offer vivid, uniform, nonfading color that can be tuned at high refresh rates (>50 Hz) and optical contrast (>50%). These dynamics scale from the single nanoparticle level to multicentimeter scale films in subwavelength thickness devices, which are a hundredfold thinner than current displays.
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Affiliation(s)
- Jialong Peng
- NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | - Hyeon-Ho Jeong
- NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | - Qianqi Lin
- NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | - Sean Cormier
- NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | - Hsin-Ling Liang
- NanoManufacturing Group, Department of Engineering, University of Cambridge, Cambridge CB3 0FS, UK
| | - Michael F. L. De Volder
- NanoManufacturing Group, Department of Engineering, University of Cambridge, Cambridge CB3 0FS, UK
| | - Silvia Vignolini
- Bio-inspired Photonics Group, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Jeremy J. Baumberg
- NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
- Corresponding author.
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56
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Baumberg JJ. Hot electron science in plasmonics and catalysis: what we argue about. Faraday Discuss 2019; 214:501-511. [PMID: 31016306 DOI: 10.1039/c9fd00027e] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Hot electron photochemistry has made strong claims for improved control of chemical reactions. Here I discuss these claims in the light of a plethora of model experiments and theories, asking what are the key issues to solve. I particularly highlight the need to understand nanoscale thermal hot-spots, thermal gradients, and thermal transport, as well as the conventional optical confinement in plasmonics. I note how the 'direct electron transfer' process seems to dominate, and resembles well known 'indirect excitons' in semiconductor quantum wells. I believe a crucial advance still required is a prototype nano-confined geometry which allows reactants and products to access a well-controlled metallic atomic surface.
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Affiliation(s)
- Jeremy J Baumberg
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thompson Avenue, Cambridge, CB3 0HE, UK.
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57
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Huang J, de Nijs B, Cormier S, Sokolowski K, Grys DB, Readman CA, Barrow SJ, Scherman OA, Baumberg JJ. Plasmon-induced optical control over dithionite-mediated chemical redox reactions. Faraday Discuss 2019; 214:455-463. [PMID: 30865195 DOI: 10.1039/c8fd00155c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
External-stimuli controlled reversible formation of radical species is of great interest for synthetic and supramolecular chemistry, molecular machinery, as well as emerging technologies ranging from (photo)catalysis and photovoltaics to nanomedicine. Here we show a novel hybrid colloidal system for light-driven reversible reduction of chemical species that, on their own, do not respond to light. This is achieved by the unique combination of photo-sensitive plasmonic aggregates and temperature-responsive inorganic species generating radicals that can be finally accepted and stabilised by non-photo-responsive organic molecules. In this system Au nanoparticles (NPs) self-assembled via sub-nm precise molecular spacers (cucurbit[n]urils) interact strongly with visible light to locally accelerate the decomposition of dithionite species (S2O42-) close to the NP interfaces. This light-driven process leads to the generation of inorganic radicals whose electrons can then be reversibly picked up by small organic acceptors, such as the methyl viologen molecules (MV2+) used here. During light-triggered plasmon- and heat-assisted generation of radicals, the S2O42- species work as a chemical 'fuel' linking photo-induced processes at the NP interfaces with redox chemistry in the surrounding water environment. By incorporating MV2+ as a Raman-active reporter molecule, the resulting optically-controlled redox processes can be followed in real-time.
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Affiliation(s)
- Junyang Huang
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thompson Avenue, Cambridge, CB3 0HE, UK.
| | - Bart de Nijs
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thompson Avenue, Cambridge, CB3 0HE, UK.
| | - Sean Cormier
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thompson Avenue, Cambridge, CB3 0HE, UK.
| | - Kamil Sokolowski
- Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - David-Benjamin Grys
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thompson Avenue, Cambridge, CB3 0HE, UK.
| | - Charlie A Readman
- Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Steven J Barrow
- Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Oren A Scherman
- Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Jeremy J Baumberg
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thompson Avenue, Cambridge, CB3 0HE, UK.
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59
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Zhang K, Liu Y, Zhao J, Liu B. Nanoscale tracking plasmon-driven photocatalysis in individual nanojunctions by vibrational spectroscopy. NANOSCALE 2018; 10:21742-21747. [PMID: 30431050 DOI: 10.1039/c8nr07447j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Plasmonic metal nanoparticles (NPs) are promising catalysts in photocatalytic reactions. Understanding the exact role of sites where two particles are approaching (hot spots) is important to achieve higher efficiency of photocatalysis, and promote the development of advanced plasmon-driven photocatalytic systems. Surface-enhanced Raman spectroscopy was employed to probe photocatalytic coupling reactions occurring at individual plasmonic nanojunctions that trap light to nanoscale while serving as nanoreactors. Compared with nanocavities fabricated using the small Ag NPs (70 nm or 82 nm), the 102 nm Ag NP-molecule-Au thin film nanojunction demonstrated enhanced reaction kinetics and catalytic efficiency. On the basis of the experimental results and theoretical modeling, it was concluded that the photochemical reaction dynamics and yields showed direct correlation with the local electric field enhancement at the nanojunction hot spot. The largely enhanced electric field generates increased hot plasmonic electrons, promoting chemical transformations of the adsorbed molecules.
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Affiliation(s)
- Kun Zhang
- Department of Chemistry, Shanghai Stomatological Hospital, State Key Laboratory of Molecular Engineering of Polymers, and Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai 200433, P. R. China.
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60
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Nian LL, Wang Y, Lü JT. On the Fano Line Shape of Single Molecule Electroluminescence Induced by a Scanning Tunneling Microscope. NANO LETTERS 2018; 18:6826-6831. [PMID: 30335393 DOI: 10.1021/acs.nanolett.8b02706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The coupling between molecular exciton and gap plasmons plays a key role in single molecular electroluminescence induced by a scanning tunneling microscope (STM). But it has been difficult to clarify the complex experimental phenomena. By employing the nonequilibrium Green's function method, we propose a general theoretical model to understand the light emission spectrum of single molecule and gap plasmons from an energy transport point of view. The coherent interaction between gap plasmons and molecular exciton leads to a prominent Fano resonance in the emission spectrum. We analyze the dependence of the Fano line shape on the system parameters, based on which we provide a unified account of several recent experimental observations. Moreover, we highlight the effect of the tip-molecule electronic coupling on the spectrum.
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Affiliation(s)
- Lei-Lei Nian
- School of Physics and Wuhan National High Magnetic Field Center , Huazhong University of Science and Technology , 430074 Wuhan , People's Republic of China
| | - Yongfeng Wang
- Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics , Peking University , 100871 Beijing , People's Republic of China
| | - Jing-Tao Lü
- School of Physics and Wuhan National High Magnetic Field Center , Huazhong University of Science and Technology , 430074 Wuhan , People's Republic of China
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61
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Szczerbiński J, Gyr L, Kaeslin J, Zenobi R. Plasmon-Driven Photocatalysis Leads to Products Known from E-beam and X-ray-Induced Surface Chemistry. NANO LETTERS 2018; 18:6740-6749. [PMID: 30277787 DOI: 10.1021/acs.nanolett.8b02426] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Plasmonic metal nanostructures can concentrate incident optical fields in nanometer-sized volumes, called hot spots. This leads to enhanced optical responses of molecules in such a hot spot but also to chemical transformations, driven by plasmon-induced hot carriers. Here, we employ tip-enhanced Raman spectroscopy (TERS) to study the mechanism of these reactions in situ at the level of a single hot spot. Direct spectroscopic measurements reveal the energy distribution of hot electrons, as well as the temperature changes due to plasmonic heating. Therefore, charge-driven reactions can be distinguished from thermal reaction pathways. The products of the hot-carrier-driven reactions are strikingly similar to the ones known from X-ray or e-beam-induced surface chemistry despite the >100-fold energy difference between visible and X-ray photons. Understanding the analogies between those two scenarios implies new strategies for rational design of plasmonic photocatalytic reactions and for the elimination of photoinduced damage in plasmon-enhanced spectroscopy.
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Affiliation(s)
- Jacek Szczerbiński
- Department of Chemistry and Applied Biosciences, Laboratory of Organic Chemistry , ETH Zurich , 8093 Zurich , Switzerland
| | - Luzia Gyr
- Department of Chemistry and Applied Biosciences, Laboratory of Organic Chemistry , ETH Zurich , 8093 Zurich , Switzerland
| | - Jérôme Kaeslin
- Department of Chemistry and Applied Biosciences, Laboratory of Organic Chemistry , ETH Zurich , 8093 Zurich , Switzerland
| | - Renato Zenobi
- Department of Chemistry and Applied Biosciences, Laboratory of Organic Chemistry , ETH Zurich , 8093 Zurich , Switzerland
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62
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Haimerl J, Ghosh I, König B, Vogelsang J, Lupton JM. Single-molecule photoredox catalysis. Chem Sci 2018; 10:681-687. [PMID: 30746104 PMCID: PMC6340401 DOI: 10.1039/c8sc03860k] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 10/21/2018] [Indexed: 11/21/2022] Open
Abstract
Photocatalytic dehalogenation by a common dyestuff under aqueous conditions is driven by energy-additive absorption of two photons on the single-molecule level.
The chemistry of life is founded on light, so is it appropriate to think of light as a chemical substance? Planck's quantization offers a metric analogous to Avogadro's number to relate the number of particles to an effective reaction of single molecules and photons to form a new compound. A rhodamine dye molecule serves as a dehalogenating photocatalyst in a consecutive photoelectron transfer (conPET) process which adds the energy of two photons, with the first photon inducing radical formation and the second photon triggering PET to the substrate molecule. Rather than probing catalytic heterogeneity and dynamics on the single-molecule level, single-photon synthesis is demonstrated: the light quantum constitutes a reactant for the single substrate molecule in a dye–driven reaction. The approach illustrates that molecular diffusion and excited-state internal conversion are not limiting factors in conPET reaction kinetics because of catalyst–substrate preassociation. The effect could be common to photoredox catalysis, removing the conventional requirement of long excited-state lifetimes.
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Affiliation(s)
- Josef Haimerl
- Institut für Experimentelle und Angewandte Physik , Universität Regensburg , 93040 Regensburg , Germany .
| | - Indrajit Ghosh
- Institut für Organische Chemie , Universität Regensburg , 93040 Regensburg , Germany
| | - Burkhard König
- Institut für Organische Chemie , Universität Regensburg , 93040 Regensburg , Germany
| | - Jan Vogelsang
- Institut für Experimentelle und Angewandte Physik , Universität Regensburg , 93040 Regensburg , Germany .
| | - John M Lupton
- Institut für Experimentelle und Angewandte Physik , Universität Regensburg , 93040 Regensburg , Germany .
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64
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Sprague-Klein EA, Negru B, Madison LR, Coste SC, Rugg BK, Felts AM, McAnally MO, Banik M, Apkarian VA, Wasielewski MR, Ratner MA, Seideman T, Schatz GC, Van Duyne RP. Photoinduced Plasmon-Driven Chemistry in trans-1,2-Bis(4-pyridyl)ethylene Gold Nanosphere Oligomers. J Am Chem Soc 2018; 140:10583-10592. [DOI: 10.1021/jacs.8b06347] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
| | | | | | | | | | - Alanna M. Felts
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | | | - Mayukh Banik
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Vartkess A. Apkarian
- Department of Chemistry, University of California, Irvine, California 92697, United States
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65
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Surface plasmon aided high sensitive non-enzymatic glucose sensor using Au/NiAu multilayered nanowire arrays. Biosens Bioelectron 2018; 111:41-46. [DOI: 10.1016/j.bios.2018.03.067] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/14/2018] [Accepted: 03/28/2018] [Indexed: 01/24/2023]
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66
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Khademi A, Dewolf T, Gordon R. Quantum plasmonic epsilon near zero: field enhancement and cloaking. OPTICS EXPRESS 2018; 26:15656-15664. [PMID: 30114823 DOI: 10.1364/oe.26.015656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 05/23/2018] [Indexed: 06/08/2023]
Abstract
We investigate the effect of the electron wave function producing permittivity (epsilon) near zero in sub-nanometer gaps and at surfaces. The field enhancement is calculated for gaps and nanoparticles, as well as the absorption from nanoparticles. Our modified quantum corrected model shows reduced absorption for nanoparticles due to "cloaking" of the epsilon near zero region, which has lower loss than the bulk region. We demonstrate that a modified quantum corrected model finite-difference time-domain simulation of metal slits with sub-nanometer gaps are in good agreement with the analytic expression for the quantum corrected plasmonic resonance wavelength as a function of gap size coming from Re{ε} = 0.
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67
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Lerch S, Reinhard BM. Effect of interstitial palladium on plasmon-driven charge transfer in nanoparticle dimers. Nat Commun 2018; 9:1608. [PMID: 29686266 PMCID: PMC5913128 DOI: 10.1038/s41467-018-04066-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 03/30/2018] [Indexed: 12/22/2022] Open
Abstract
Capacitive plasmon coupling between noble metal nanoparticles (NPs) is characterized by an increasing red-shift of the bonding dipolar plasmon mode (BDP) in the classical electromagnetic coupling regime. This model breaks down at short separations where plasmon-driven charge transfer induces a gap current between the NPs with a magnitude and separation dependence that can be modulated if molecules are present in the gap. Here, we use gap contained DNA as a scaffold for the growth of palladium (Pd) NPs in the gap between two gold NPs and investigate the effect of increasing Pd NP concentration on the BDP mode. Consistent with enhanced plasmon-driven charge transfer, the integration of discrete Pd NPs depolarizes the capacitive BDP mode over longer interparticle separations than is possible in only DNA-linked Au NPs. High Pd NP densities in the gap increases the gap conductance and induces the transition from capacitive to conductive coupling. Plasmon coupling between nanoparticles may depend not only on interparticle gap distance, but also on gap conductance. Here, the authors modify the gap conductance—and thus the plasmon response—between gold nanoparticle dimers by growing varying amounts of palladium nanoparticles in the gap.
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Affiliation(s)
- Sarah Lerch
- Department of Chemistry and The Photonics Center, Boston University, 8 Saint Mary's Street, Boston, MA, 02215, USA
| | - Björn M Reinhard
- Department of Chemistry and The Photonics Center, Boston University, 8 Saint Mary's Street, Boston, MA, 02215, USA.
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Abstract
Abstract
The assembly of metal nanocrystals offers a flexible method for creating new materials with tunable, size-dependent optical properties. Here we study the lateral assembly of gold nanorods into arrays, which leads to strong colour changes due to surface plasmon coupling. We also demonstrate the first example of gap modes in colloid systems, an optical mode in which light waves propagate in the channels between the gold rods. Such modes resonate at wavelengths which strongly depend on the gap width and length.
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69
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Simoncelli S, Li Y, Cortés E, Maier SA. Nanoscale Control of Molecular Self-Assembly Induced by Plasmonic Hot-Electron Dynamics. ACS NANO 2018; 12:2184-2192. [PMID: 29346720 DOI: 10.1021/acsnano.7b08563] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Self-assembly processes allow designing and creating complex nanostructures using molecules as building blocks and surfaces as scaffolds. This autonomous driven construction is possible due to a complex thermodynamic balance of molecule-surface interactions. As such, nanoscale guidance and control over this process is hard to achieve. Here we use the highly localized light-to-chemical-energy conversion of plasmonic materials to spatially cleave Au-S bonds on predetermined locations within a single nanoparticle, enabling a high degree of control over this archetypal system for molecular self-assembly. Our method offers nanoscale precision and high-throughput light-induced tailoring of the surface chemistry of individual and packed nanosized metallic structures by simply varying wavelength and polarization of the incident light. Assisted by single-molecule super-resolution fluorescence microscopy, we image, quantify, and shed light onto the plasmon-induced desorption mechanism. Our results point toward localized distribution of hot electrons, contrary to uniformly distributed lattice heating, as the mechanism inducing Au-S bond breaking. We demonstrate that plasmon-induced photodesorption enables subdiffraction and even subparticle multiplexing. Finally, we explore possible routes to further exploit these concepts for the selective positioning of nanomaterials and the sorting and purification of colloidal nanoparticles.
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Affiliation(s)
- Sabrina Simoncelli
- The Blackett Laboratory, Department of Physics , Imperial College London , London SW7 2AZ , United Kingdom
| | - Yi Li
- The Blackett Laboratory, Department of Physics , Imperial College London , London SW7 2AZ , United Kingdom
| | - Emiliano Cortés
- The Blackett Laboratory, Department of Physics , Imperial College London , London SW7 2AZ , United Kingdom
| | - Stefan A Maier
- The Blackett Laboratory, Department of Physics , Imperial College London , London SW7 2AZ , United Kingdom
- Chair in Hybrid Nanosystems, Faculty of Physics , Ludwig-Maximilians-Universität München , 80799 München , Germany
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Bi H, Palma CA, Gong Y, Hasch P, Elbing M, Mayor M, Reichert J, Barth JV. Voltage-Driven Conformational Switching with Distinct Raman Signature in a Single-Molecule Junction. J Am Chem Soc 2018; 140:4835-4840. [DOI: 10.1021/jacs.7b12818] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Hai Bi
- Physics Department E20, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
| | - Carlos-Andres Palma
- Physics Department E20, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
- Institute of Physics, Chinese Academy of Sciences, 100190 Beijing, P.R. China
| | - Yuxiang Gong
- Physics Department E20, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
| | - Peter Hasch
- Physics Department E20, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
| | - Mark Elbing
- Department of Applied Natural Sciences, Lübeck University of Applied Sciences, Mönkhofer Weg 239, 23562 Lübeck, Germany
| | - Marcel Mayor
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Karlsruhe, Germany
- Department of Chemistry, University of Basel, St Johannsring 19, CH-4056 Basel, Switzerland
| | - Joachim Reichert
- Physics Department E20, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
| | - Johannes V. Barth
- Physics Department E20, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
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Abstract
Chemical activity of single nanoparticles can be imaged and determined by monitoring the optical signal of each individual during chemical reactions with advanced optical microscopes. It allows for clarifying the functional heterogeneity among individuals, and for uncovering the microscopic reaction mechanisms and kinetics that could otherwise be averaged out in ensemble measurements.
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Affiliation(s)
- Wei Wang
- State Key Laboratory of Analytical Chemistry for Life Science
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing 210023
- China
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