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Haldar A, Cortes CL, Darancet P, Sharifzadeh S. Microscopic Theory of Plasmons in Substrate-Supported Borophene. NANO LETTERS 2020; 20:2986-2992. [PMID: 32208703 DOI: 10.1021/acs.nanolett.9b04789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We compute the dielectric properties of freestanding and metal-supported borophene from first-principles time-dependent density functional theory. We find that both the low- and high-energy plasmons of borophene are fully quenched by the presence of a metallic substrate at borophene-metal distances smaller than ≃9 Å. Based on these findings, we derive an electrodynamic model of the interacting, momentum-dependent polarizability for a two-dimensional metal on a model metallic substrate, which quantitatively captures the evolution of the dielectric properties of borophene as a function of metal-borophene distance. Applying this model to a series of metallic substrates, we show that maximizing the plasmon energy detuning between borophene and substrate is the key material descriptor for plasmonic performance.
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Affiliation(s)
- Anubhab Haldar
- Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215, United States
| | - Cristian L Cortes
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Pierre Darancet
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
- Northwestern Argonne Institute of Science and Engineering, Evanston, Illinois 60208, United States
| | - Sahar Sharifzadeh
- Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215, United States
- Division of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, United States
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52
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Wallum A, Nguyen HA, Gruebele M. Excited-State Imaging of Single Particles on the Subnanometer Scale. Annu Rev Phys Chem 2020; 71:415-433. [DOI: 10.1146/annurev-physchem-071119-040108] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
At the intersection of spectroscopy and microscopy lie techniques that are capable of providing subnanometer imaging of excited states of individual molecules or nanoparticles. Such approaches are particularly important for imaging macromolecules or nanoparticles large enough to have a high probability of containing a defect. These inevitable defects often control properties and function despite an otherwise ideal structure. We discuss real-space imaging techniques such as using scanning tunneling microscopy tips to enhance optical measurements and electron energy-loss spectroscopy in a scanning transmission electron microscope, which is based on focused electron beams to obtain high-resolution spatial information on excited states. The outlook for these methods is bright, as they will provide critical information for the characterization and improvement of energy-switching, electron-switching, and energy-harvesting materials.
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Affiliation(s)
- Alison Wallum
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Huy A. Nguyen
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Martin Gruebele
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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53
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Schütz S, Schachenmayer J, Hagenmüller D, Brennen GK, Volz T, Sandoghdar V, Ebbesen TW, Genes C, Pupillo G. Ensemble-Induced Strong Light-Matter Coupling of a Single Quantum Emitter. PHYSICAL REVIEW LETTERS 2020; 124:113602. [PMID: 32242709 DOI: 10.1103/physrevlett.124.113602] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 02/18/2020] [Indexed: 05/04/2023]
Abstract
We discuss a technique to strongly couple a single target quantum emitter to a cavity mode, which is enabled by virtual excitations of a nearby mesoscopic ensemble of emitters. A collective coupling of the latter to both the cavity and the target emitter induces strong photon nonlinearities in addition to polariton formation, in contrast to common schemes for ensemble strong coupling. We demonstrate that strong coupling at the level of a single emitter can be engineered via coherent and dissipative dipolar interactions with the ensemble, and provide realistic parameters for a possible implementation with SiV^{-} defects in diamond. Our scheme can find applications, amongst others, in quantum information processing or in the field of cavity-assisted quantum chemistry.
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Affiliation(s)
- S Schütz
- ISIS (UMR 7006) and icFRC, University of Strasbourg and CNRS, 67000 Strasbourg, France
| | - J Schachenmayer
- ISIS (UMR 7006) and IPCMS (UMR 7504), University of Strasbourg and CNRS, 67000 Strasbourg, France
| | - D Hagenmüller
- ISIS (UMR 7006) and icFRC, University of Strasbourg and CNRS, 67000 Strasbourg, France
| | - G K Brennen
- Department of Physics & Astronomy and ARC Centre of Excellence for Engineered Quantum Systems, Macquarie University, New South Wales 2109, Australia
| | - T Volz
- Department of Physics & Astronomy and ARC Centre of Excellence for Engineered Quantum Systems, Macquarie University, New South Wales 2109, Australia
| | - V Sandoghdar
- Max Planck Institute for the Science of Light, Staudtstraße 2, D-91058 Erlangen, Germany
- Department of Physics, University of Erlangen-Nuremberg, Staudtstraße 7, D-91058 Erlangen, Germany
| | - T W Ebbesen
- ISIS (UMR 7006) and icFRC, University of Strasbourg and CNRS, 67000 Strasbourg, France
| | - C Genes
- Max Planck Institute for the Science of Light, Staudtstraße 2, D-91058 Erlangen, Germany
- Department of Physics, University of Erlangen-Nuremberg, Staudtstraße 7, D-91058 Erlangen, Germany
| | - G Pupillo
- ISIS (UMR 7006) and icFRC, University of Strasbourg and CNRS, 67000 Strasbourg, France
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54
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Zhang MX, You EM, Zheng P, Ding SY, Tian ZQ, Moskovits M. Accurately Predicting the Radiation Enhancement Factor in Plasmonic Optical Antenna Emitters. J Phys Chem Lett 2020; 11:1947-1953. [PMID: 32079400 DOI: 10.1021/acs.jpclett.0c00304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Plasmonic optical antennas (POAs), often constructed from gold or silver nanostructures, can enhance the radiation efficiency of emitters coupled to POAs and are applied in surface-enhanced Raman spectroscopy (SERS) and light-emitting devices. Over the past four decades, radiation enhancement factors (REFs) of POA-emitter systems were considered to be difficult to calculate directly and have been predicted indirectly and approximately, assuming POAs are illuminated by electromagnetic plane waves without emitters. The validity of this approximation remains a significant open problem in SERS theory. Herein, we develop a method based on the rigorous optical reciprocity theorem for accurately calculating the REFs of emitters in nanoparticle-substrate nanogaps for single-molecule SERS and scanning probe-substrate nanogaps for tip-enhanced Raman spectroscopy. We show that the validity of the plane wave approximation breaks down if high-order plasmonic modes are excited. The as-developed method paves the way toward designing high-REF POA nanostructures for luminescence-related devices.
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Affiliation(s)
- Mao-Xin Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS), Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - En-Ming You
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS), Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Peng Zheng
- School of Aerospace Engineering, Xiamen University, Xiamen 361005, China
| | - Song-Yuan Ding
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS), Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Zhong-Qun Tian
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS), Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Martin Moskovits
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
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55
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Wen SS, Huang YG, Wang XY, Liu J, Li Y, Quan XE, Yang H, Peng JZ, Deng K, Zhao HP. Bound state and non-Markovian dynamics of a quantum emitter around a surface plasmonic nanostructure. OPTICS EXPRESS 2020; 28:6469-6489. [PMID: 32225894 DOI: 10.1364/oe.386828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 02/05/2020] [Indexed: 06/10/2023]
Abstract
A bound state between a quantum emitter (QE) and surface plasmon polaritons (SPPs) can be formed, where the excited QE will not relax completely to its ground state and is partially stabilized in its excited state after a long time. We develop some theoretical methods for investigating this problem and show how to form such a bound state and its effect on the non-Markovian decay dynamics. We put forward an efficient numerical approach for calculating the analytical part of the self-energy for frequency below the lower energy threshold. We also propose an efficient formalism for obtaining the long-time value of the excited-state population without calculating the eigenfrequency of the bound state or performing a time evolution of the system, in which the probability amplitude for the excited state in the steady limit is equal to one minus the integral of the evolution spectrum over the positive frequency range. With the above two quantities obtained, we show that the non-Markovian decay dynamics of an initially excited QE can be efficiently obtained by the method based on the Green's function expression for the evolution operator when a bound state exists. A general criterion for identifying the existence of a bound state is presented. The performances of the above methods are numerically demonstrated for a QE located around a metal nanosphere and in a gap plasmonic nanocavity. Numerical results show that these methods work well and the QE becomes partially stabilized in its excited state at a long time for the transition dipole moment beyond its critical value. In addition, it is also found that this critical value is heavily dependent on the distance between the QE and the metal surface, but nearly independent on the size of the nanosphere or the rod. Our methods can be utilized to understand the suppressed decay dynamics for a QE in an open quantum system and provide a general picture on how to form such a bound state.
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56
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Doppagne B, Neuman T, Soria-Martinez R, López LEP, Bulou H, Romeo M, Berciaud S, Scheurer F, Aizpurua J, Schull G. Single-molecule tautomerization tracking through space- and time-resolved fluorescence spectroscopy. NATURE NANOTECHNOLOGY 2020; 15:207-211. [PMID: 31959932 DOI: 10.1038/s41565-019-0620-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 12/09/2019] [Indexed: 05/21/2023]
Abstract
Tautomerization, the interconversion between two constitutional molecular isomers, is ubiquitous in nature1, plays a major role in chemistry2 and is perceived as an ideal switch function for emerging molecular-scale devices3. Within free-base porphyrin4, porphycene5 or phthalocyanine6, this process involves the concerted or sequential hopping of the two inner hydrogen atoms between equivalent nitrogen sites of the molecular cavity. Electronic and vibronic changes6 that result from this NH tautomerization, as well as details of the switching mechanism, were extensively studied with optical spectroscopies, even with single-molecule sensitivity7. The influence of atomic-scale variations of the molecular environment and submolecular spatial resolution of the tautomerization could only be investigated using scanning probe microscopes3,8-11, at the expense of detailed information provided by optical spectroscopies. Here, we combine these two approaches, scanning tunnelling microscopy (STM) and fluorescence spectroscopy12-15, to study the tautomerization within individual free-base phthalocyanine (H2Pc) molecules deposited on a NaCl-covered Ag(111) single-crystal surface. STM-induced fluorescence (STM-F) spectra exhibit duplicate features that we assign to the emission of the two molecular tautomers. We support this interpretation by comparing hyper-resolved fluorescence maps15-18(HRFMs) of the different spectral contributions with simulations that account for the interaction between molecular excitons and picocavity plasmons19. We identify the orientation of the molecular optical dipoles, determine the vibronic fingerprint of the tautomers and probe the influence of minute changes in their atomic-scale environment. Time-correlated fluorescence measurements allow us to monitor the tautomerization events and to associate the proton dynamics to a switching two-level system. Finally, optical spectra acquired with the tip located at a nanometre-scale distance from the molecule show that the tautomerization reaction occurs even when the tunnelling current does not pass through the molecule. Together with other observations, this remote excitation indicates that the excited state of the molecule is involved in the tautomerization reaction path.
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Affiliation(s)
| | - Tomáš Neuman
- Center for Materials Physics (CSIC-UPV/EHU) and DIPC, Donostia-San Sebastián, Spain
| | | | | | - Hervé Bulou
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, Strasbourg, France
| | | | | | - Fabrice Scheurer
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, Strasbourg, France
| | - Javier Aizpurua
- Center for Materials Physics (CSIC-UPV/EHU) and DIPC, Donostia-San Sebastián, Spain
| | - Guillaume Schull
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, Strasbourg, France.
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57
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58
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Xia J, Tang J, Bao F, Evans J, He S. Channel competition in emitter-plasmon coupling. OPTICS EXPRESS 2019; 27:30893-30908. [PMID: 31684331 DOI: 10.1364/oe.27.030893] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 09/19/2019] [Indexed: 06/10/2023]
Abstract
When an emitter is close to a plasmonic nanoantenna, besides coupling to the dipolar antenna mode, the emitter also considerably couples to a superposition of the high-order modes, referred to as a pseudomode. We comprehensively investigate the differences between the dipolar mode channel and the pseudomode channel in a representative system where a dipole emitter couples to a silver nanorod. The two channels are shown to be distinct in their mechanisms, characteristics (including chromatic dispersion and field distribution), and dependences on system parameters (including emitter-antenna distance, antenna geometry, and material loss). The study provides physical insight and reveals important design rules for controlling the competition between the two channels.
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59
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Yang M, Mattei MS, Cherqui CR, Chen X, Van Duyne RP, Schatz GC. Tip-Enhanced Raman Excitation Spectroscopy (TERES): Direct Spectral Characterization of the Gap-Mode Plasmon. NANO LETTERS 2019; 19:7309-7316. [PMID: 31518135 DOI: 10.1021/acs.nanolett.9b02925] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The plasmonic properties of tip-substrate composite systems are of vital importance to near-field optical spectroscopy, in particular tip-enhanced Raman spectroscopy (TERS), which enables operando studies of nanoscale chemistry at a single molecule level. The nanocavities formed in the tip-substrate junction also offer a highly tunable platform for studying field-matter interactions at the nanoscale. While the coupled nanoparticle dimer model offers a correct qualitative description of gap-mode plasmon effects, it ignores the full spectrum of multipolar tip plasmon modes and their interaction with surface plasmon polariton (SPP) excitation in the substrate. Herein, we perform the first tip-enhanced Raman excitation spectroscopy (TERES) experiment and use the results, both in ambient and aqueous media, in combination with electrodynamics simulations, to explore the plasmonic response of a Au tip-Au substrate composite system. The gap-mode plasmon features a wide spectral window corresponding to a host of tip plasmon modes interacting with the plasmonic substrate. Simulations of the electric field confinement demonstrate that optimal spatial resolution is achieved when a hybrid plasmon mode that combines a multipolar tip plasmon and a substrate SPP is excited. Nevertheless, a wide spectral window over 1000 nm is available for exciting the tip plasmon with high spatial resolution, which enables the simultaneous resonant detection of different molecular species. This window is robust as a function of tip-substrate distance and tip radius of curvature, indicating that many choices of tips will work, but it is restricted to wavelengths longer than ∼600 nm for the Au tip-Au substrate combination. Other combinations, such as Ag tip-Ag substrate, can access wavelengths as low as 350 nm.
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Affiliation(s)
- Muwen Yang
- Department of Chemistry and Applied Physics Program , Northwestern University , Evanston , Illinois 60208 , United States
| | - Michael S Mattei
- Department of Chemistry and Applied Physics Program , Northwestern University , Evanston , Illinois 60208 , United States
| | - Charles R Cherqui
- Department of Chemistry and Applied Physics Program , Northwestern University , Evanston , Illinois 60208 , United States
| | - Xu Chen
- Department of Chemistry and Applied Physics Program , Northwestern University , Evanston , Illinois 60208 , United States
| | - Richard P Van Duyne
- Department of Chemistry and Applied Physics Program , Northwestern University , Evanston , Illinois 60208 , United States
| | - George C Schatz
- Department of Chemistry and Applied Physics Program , Northwestern University , Evanston , Illinois 60208 , United States
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60
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Pelton M, Storm SD, Leng H. Strong coupling of emitters to single plasmonic nanoparticles: exciton-induced transparency and Rabi splitting. NANOSCALE 2019; 11:14540-14552. [PMID: 31364684 DOI: 10.1039/c9nr05044b] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Strong coupling between plasmons in metal nanoparticles and single excitons in molecules or semiconductor nanomaterials has recently attracted considerable experimental effort for potential applications in quantum-mechanical and classical optical information processing and for fundamental studies of light-matter interaction. Here, we review the theory behind strong plasmon-exciton coupling and provide analytical expressions that can be used for fitting experimental data, particularly the commonly measured scattering spectra. We re-analyze published data using these expressions, providing a uniform method for evaluating and quantifying claims of strong coupling that avoids ambiguities in distinguishing between Rabi splitting and exciton-induced transparency (or Fano-like interference between plasmons and excitons).
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Affiliation(s)
- Matthew Pelton
- Department of Physics, UMBC (University of Maryland, Baltimore County), 1000 Hilltop Circle, Baltimore, MD 21250, USA.
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61
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Luo Y, Chen G, Zhang Y, Zhang L, Yu Y, Kong F, Tian X, Zhang Y, Shan C, Luo Y, Yang J, Sandoghdar V, Dong Z, Hou JG. Electrically Driven Single-Photon Superradiance from Molecular Chains in a Plasmonic Nanocavity. PHYSICAL REVIEW LETTERS 2019; 122:233901. [PMID: 31298910 DOI: 10.1103/physrevlett.122.233901] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Indexed: 05/21/2023]
Abstract
We demonstrate single-photon superradiance from artificially constructed nonbonded zinc-phthalocyanine molecular chains of up to 12 molecules. We excite the system via electron tunneling in a plasmonic nanocavity and quantitatively investigate the interaction of the localized plasmon with single-exciton superradiant states resulting from dipole-dipole coupling. Dumbbell-like patterns obtained by subnanometer resolved spectroscopic imaging disclose the coherent nature of the coupling associated with superradiant states while second-order photon correlation measurements demonstrate single-photon emission. The combination of spatially resolved spectral measurements with theoretical considerations reveals that nanocavity plasmons dramatically modify the linewidth and intensity of emission from the molecular chains, but they do not dictate the intrinsic coherence of the superradiant states. Our studies shed light on the optical properties of molecular collective states and their interaction with nanoscopically localized plasmons.
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Affiliation(s)
- Yang Luo
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Gong Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- School of Physics and Engineering, Zhengzhou University, Zhengzhou 450052, China
| | - Yang Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Li Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yunjie Yu
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Fanfang Kong
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiaojun Tian
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yao Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Chongxin Shan
- School of Physics and Engineering, Zhengzhou University, Zhengzhou 450052, China
| | - Yi Luo
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jinlong Yang
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Vahid Sandoghdar
- Max Planck Institute for the Science of Light, Erlangen 91058, Germany
| | - Zhenchao Dong
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - J G Hou
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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62
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Böckmann H, Liu S, Müller M, Hammud A, Wolf M, Kumagai T. Near-Field Manipulation in a Scanning Tunneling Microscope Junction with Plasmonic Fabry-Pérot Tips. NANO LETTERS 2019; 19:3597-3602. [PMID: 31070928 PMCID: PMC6750903 DOI: 10.1021/acs.nanolett.9b00558] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 04/26/2019] [Indexed: 05/10/2023]
Abstract
Near-field manipulation in plasmonic nanocavities can provide various applications in nanoscale science and technology. In particular, a gap plasmon in a scanning tunneling microscope (STM) junction is of key interest to nanoscale imaging and spectroscopy. Here we show that spectral features of a plasmonic STM junction can be manipulated by nanofabrication of Au tips using focused ion beam. An exemplary Fabry-Pérot type resonator of surface plasmons is demonstrated by producing the tip with a single groove on its shaft. Scanning tunneling luminescence spectra of the Fabry-Pérot tips exhibit spectral modulation resulting from interference between localized and propagating surface plasmon modes. In addition, the quality factor of the plasmonic Fabry-Pérot interference can be improved by optimizing the overall tip shape. Our approach paves the way for near-field imaging and spectroscopy with a high degree of accuracy.
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Affiliation(s)
- Hannes Böckmann
- Department of Physical Chemistry and Department of Inorganic Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Shuyi Liu
- Department of Physical Chemistry and Department of Inorganic Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Melanie Müller
- Department of Physical Chemistry and Department of Inorganic Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Adnan Hammud
- Department of Physical Chemistry and Department of Inorganic Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Martin Wolf
- Department of Physical Chemistry and Department of Inorganic Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Takashi Kumagai
- Department of Physical Chemistry and Department of Inorganic Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
- JST-PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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63
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Miwa K, Imada H, Imai-Imada M, Kimura K, Galperin M, Kim Y. Many-Body State Description of Single-Molecule Electroluminescence Driven by a Scanning Tunneling Microscope. NANO LETTERS 2019; 19:2803-2811. [PMID: 30694065 DOI: 10.1021/acs.nanolett.8b04484] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Electron transport and optical properties of a single molecule in contact with conductive materials have attracted considerable attention because of their scientific importance and potential applications. With the recent progress in experimental techniques, especially by virtue of scanning tunneling microscope (STM)-induced light emission, where the tunneling current of the STM is used as an atomic-scale source for induction of light emission from a single molecule, it has become possible to investigate single-molecule properties at subnanometer spatial resolution. Despite extensive experimental studies, the microscopic mechanism of electronic excitation of a single molecule in STM-induced light emission has yet to be clarified. Here we present a formulation of single-molecule electroluminescence driven by electron transfer between a molecule and metal electrodes based on a many-body state representation of the molecule. The effects of intramolecular Coulomb interaction on conductance and luminescence spectra are investigated using the nonequilibrium Hubbard Green's function technique combined with first-principles calculations. We compare simulation results with experimental data and find that the intramolecular Coulomb interaction is crucial for reproducing recent experiments for a single phthalocyanine molecule. The developed theory provides a unified description of the electron transport and optical properties of a single molecule in contact with metal electrodes driven out of equilibrium, and thereby, it contributes to a microscopic understanding of optoelectronic conversion in single molecules on solid surfaces and in nanometer-scale junctions.
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Affiliation(s)
- Kuniyuki Miwa
- Surface and Interface Science Laboratory , RIKEN , Wako , Saitama 351-0198 , Japan
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Hiroshi Imada
- Surface and Interface Science Laboratory , RIKEN , Wako , Saitama 351-0198 , Japan
| | - Miyabi Imai-Imada
- Surface and Interface Science Laboratory , RIKEN , Wako , Saitama 351-0198 , Japan
- Department of Advanced Materials Science, Graduate School of Frontier Science , The University of Tokyo , Kashiwa , Chiba 277-8651 , Japan
| | - Kensuke Kimura
- Surface and Interface Science Laboratory , RIKEN , Wako , Saitama 351-0198 , Japan
- Department of Advanced Materials Science, Graduate School of Frontier Science , The University of Tokyo , Kashiwa , Chiba 277-8651 , Japan
| | - Michael Galperin
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Yousoo Kim
- Surface and Interface Science Laboratory , RIKEN , Wako , Saitama 351-0198 , Japan
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64
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Chen G, Luo Y, Gao H, Jiang J, Yu Y, Zhang L, Zhang Y, Li X, Zhang Z, Dong Z. Spin-Triplet-Mediated Up-Conversion and Crossover Behavior in Single-Molecule Electroluminescence. PHYSICAL REVIEW LETTERS 2019; 122:177401. [PMID: 31107062 DOI: 10.1103/physrevlett.122.177401] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 02/22/2019] [Indexed: 05/24/2023]
Abstract
Scanning-tunneling-microscope-induced light emission serves as a powerful approach in revealing and manipulating the optical properties of molecular species, intermolecular energy transfer, and plasmon-molecule coupling. Earlier studies have established the existence of molecular up-conversion electroluminescence in diverse situations, but the underlying microscopic mechanisms are still under active debate, dominated by intermolecular triplet-triplet annihilation and plasmonic pumping. Here we report on the experimental realization of up-conversion electroluminescence from a prototypical single phthalocyanine molecule, allowing us to unambiguously rule out mechanisms based on intermolecular coupling and also offering unprecedented opportunities to elucidate much richer characteristics unforeseen in previous studies. In particular, the bias-dependent emission intensity displays three distinct regions with different nonlinear current dependences, which can be attributed to crossover behavior caused by the interplay between inelastic electron scattering and carrier-injection processes. We also develop a microscopic description to capture the essential physics involved in up-conversion electroluminescence mediated by a proper intermediate spin-triplet state.
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Affiliation(s)
- Gong Chen
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
- School of Physics and Engineering, Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Yang Luo
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hongying Gao
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jun Jiang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yunjie Yu
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Li Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yang Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiaoguang Li
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
| | - Zhenyu Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhenchao Dong
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
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65
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Transformation from Quantum to Classical Mode: the Size Effect of Plasmon in 2D Atomic Cluster System. Sci Rep 2019; 9:6641. [PMID: 31036936 PMCID: PMC6488700 DOI: 10.1038/s41598-019-43249-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 04/17/2019] [Indexed: 11/28/2022] Open
Abstract
On the basis of tight-binding approximation, the energy absorption of 2D atomic clusters is calculated by the linear response theory. Through the energy-absorption peaks in the presence of different external potentials, various types of plasmon modes are specified in clusters with dozens to hundreds atoms, such as transverse dipole plasmon, longitudinal dipole plasmon, transverse quadrupole plasmon, and longitudinal quadrupole plasmon. Moreover, the transformation of plasmon from quantum to classical mode is observed in clusters with different shape and different electron density. The particular transformation process demonstrate that: there are only a few modes of plasmon in clusters with few-atoms; as the number of atoms in cluster is increased, the number of plasmon modes increases, the gaps between plasmon frequencies become smaller, the quantum modes of plasmon gradually evolve into continuous modes, and the dispersion of quantum-mode plasmon gradually transforms into the one of classical 2D plasmon. Such process reveals the size effect of plasmon in 2D clusters, which can be explained by the fact that the energy levels near the Fermi energy are denser and more compact in larger-size clusters.
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66
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Wang Y, Li H, Zhu W, He F, Huang Y, Chong R, Kou D, Zhang W, Meng X, Fang X. Plasmon-mediated nonradiative energy transfer from a conjugated polymer to a plane of graphene-nanodot-supported silver nanoparticles: an insight into characteristic distance. NANOSCALE 2019; 11:6737-6746. [PMID: 30907396 DOI: 10.1039/c8nr09576k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Hybrid nanostructures comprising conjugated polymers (CPs) and plasmonic metals show excellent performance in light harvesting. However, the energy transfer mechanism of the CP film to nearby metal nanoparticles, especially knowledge of the characteristic distance, is still unclear. Here, quenching of the emission of a CP film in proximity to a monolayer of graphene-nanodot-supported silver nanoparticles (GND-Ag NPs) is investigated. Uniform Ag NPs with D = 3.2 nm were grown on GNDs in situ under mild light irradiation, and a series of bilayer structures of GND-Ag NPs/CPs were constructed by spin-coating blue, green and red light-emitting poly(9,9-dioctylfluorene) (PFO), poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) and poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV),respectively, on top of the GND-Ag NP plane. The spacer distance was controlled by the layers of assembled polyelectrolytes. Both steady and transient photoluminescence (PL) spectra showed emission quenching of the bilayer structures, providing the maximum efficiency of 99% for the F8BT films. The surface density of GND-Ag NPs and the spacer distance-dependent PL quenching data were analyzed within the plasmonic resonant energy transfer model, and the extracted characteristic distances are 6 nm, 3 nm and 10 nm for the PFO, F8BT and MEH-PPV systems, respectively. Current-sensing atomic force microscopy shows that the GND-Ag NPs/F8BT film exhibits enhanced electrical conductivity. These results are believed to be important for the development of plasmonic enhanced polymer photovoltaics and photocatalysis.
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Affiliation(s)
- Yunjing Wang
- Institute of Fine Chemistry and Engineering, Henan Engineering Laboratory of Flame-Retardant and Functional Materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, P. R. China.
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67
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Ojambati OS, Chikkaraddy R, Deacon WD, Horton M, Kos D, Turek VA, Keyser UF, Baumberg JJ. Quantum electrodynamics at room temperature coupling a single vibrating molecule with a plasmonic nanocavity. Nat Commun 2019; 10:1049. [PMID: 30837456 PMCID: PMC6400948 DOI: 10.1038/s41467-019-08611-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 01/21/2019] [Indexed: 11/08/2022] Open
Abstract
Interactions between a single emitter and cavity provide the archetypical system for fundamental quantum electrodynamics. Here we show that a single molecule of Atto647 aligned using DNA origami interacts coherently with a sub-wavelength plasmonic nanocavity, approaching the cooperative regime even at room temperature. Power-dependent pulsed excitation reveals Rabi oscillations, arising from the coupling of the oscillating electric field between the ground and excited states. The observed single-molecule fluorescent emission is split into two modes resulting from anti-crossing with the plasmonic mode, indicating the molecule is strongly coupled to the cavity. The second-order correlation function of the photon emission statistics is found to be pump wavelength dependent, varying from g(2)(0) = 0.4 to 1.45, highlighting the influence of vibrational relaxation on the Jaynes-Cummings ladder. Our results show that cavity quantum electrodynamic effects can be observed in molecular systems at ambient conditions, opening significant potential for device applications.
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Affiliation(s)
- Oluwafemi S Ojambati
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, JJ Thompson Avenue, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Rohit Chikkaraddy
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, JJ Thompson Avenue, University of Cambridge, Cambridge, CB3 0HE, UK
| | - William D Deacon
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, JJ Thompson Avenue, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Matthew Horton
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, JJ Thompson Avenue, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Dean Kos
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, JJ Thompson Avenue, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Vladimir A Turek
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, JJ Thompson Avenue, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Ulrich F Keyser
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, JJ Thompson Avenue, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Jeremy J Baumberg
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, JJ Thompson Avenue, University of Cambridge, Cambridge, CB3 0HE, UK.
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68
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Mehler A, Néel N, Bocquet ML, Kröger J. Exciting vibrons in both frontier orbitals of a single hydrocarbon molecule on graphene. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:065001. [PMID: 30523960 DOI: 10.1088/1361-648x/aaf54c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Vibronic excitations in molecules are key to the fundamental understanding of the interaction between vibrational and electronic degrees of freedom. In order to probe the genuine vibronic properties of a molecule even after its adsorption on a surface appropriate buffer layers are of paramount importance. Here, vibrational progression in both molecular frontier orbitals is observed with submolecular resolution on a graphene-covered metal surface using scanning tunnelling spectroscopy. Accompanying calculations demonstrate that the vibrational modes that cause the orbital replica in the progression share the same symmetry as the electronic states they couple to. In addition, the vibrational progression is more pronounced for separated molecules than for molecules embedded in molecular assemblies. The entire vibronic spectra of these molecular species are moreover rigidly shifted with respect to each other. This work unravels intramolecular changes in the vibronic and electronic structure owing to the efficient reduction of the molecule-metal hybridization by graphene.
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Affiliation(s)
- A Mehler
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
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69
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Muhammed MM, Mokkath JH. Linear acene molecules in plasmonic cavities: mapping evolution of optical absorption spectra and electric field intensity enhancements. NEW J CHEM 2019. [DOI: 10.1039/c9nj02132a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Understanding the plasmonic cavity induced electric field enhancement in a hybrid nanosystem is of paramount importance in the development of new optical devices.
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Affiliation(s)
- Mufasila Mumthaz Muhammed
- Quantum Nanophotonics Simulations Lab
- Department of Physics
- Kuwait College of Science And Technology
- Kuwait
| | - Junais Habeeb Mokkath
- Quantum Nanophotonics Simulations Lab
- Department of Physics
- Kuwait College of Science And Technology
- Kuwait
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70
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Edelmann K, Gerhard L, Winkler M, Wilmes L, Rai V, Schumann M, Kern C, Meyer M, Wegener M, Wulfhekel W. Light collection from a low-temperature scanning tunneling microscope using integrated mirror tips fabricated by direct laser writing. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:123107. [PMID: 30599551 DOI: 10.1063/1.5053882] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 11/08/2018] [Indexed: 05/24/2023]
Abstract
We report on a cryogenic scanning tunneling microscope (STM) designed for single molecule studies, in which the light emitted from the tunneling junction is collected by an integrated optics on the tip. Using direct laser writing, the tip and the surrounding microscopic parabolic mirror are fabricated as one piece, which is small enough to collimate the collected light directly into an optical multimode fiber fixed inside the STM. This simple and compact setup combines high collection efficiency and ease of handling while not interfering with the cryostat operation, allowing uninterrupted measurements at 1.4 K for up to 5 days with low drift.
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Affiliation(s)
- Kevin Edelmann
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen, Germany
| | - Lukas Gerhard
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen, Germany
| | - Moritz Winkler
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen, Germany
| | - Lars Wilmes
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen, Germany
| | - Vibhuti Rai
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen, Germany
| | - Martin Schumann
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen, Germany
| | - Christian Kern
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen, Germany
| | - Michael Meyer
- Physikalisches Institut, Karlsruhe Institute of Technology (KIT), D-76131 Karlsruhe, Germany
| | - Martin Wegener
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen, Germany
| | - Wulf Wulfhekel
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen, Germany
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71
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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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72
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Lu Y, Chen Y, Xu J, Wang T, Lü JT. Decay channels of gap plasmons in STM tunnel junctions. OPTICS EXPRESS 2018; 26:30444-30455. [PMID: 30469918 DOI: 10.1364/oe.26.030444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 10/11/2018] [Indexed: 06/09/2023]
Abstract
We study the decay of gap plasmons localized between a scanning tunneling microscope tip and metal substrate, excited by inelastic tunneling electrons. The overall excited energy from the tunneling electrons is divided into two categories in the form of resistive dissipation and electromagnetic radiation, which together can further be separated into four diffierent channels, including SPP channel on the tip, SPP channel on the substrate, air mode channel and direct quenching channel. In this work, we study the enhancement factor, i.e. Purcell factor, of the STM tunnel junctions, which are mediated by the nearby metallic structures. We find that the gap plasmon mode is most likely to couple to the SPP channel on the tip, rather than the SPP channel on the substrate or the air mode. The direct quenching in the apex of tip also takes a considerable portion especially in high frequency region, the enhancement factor of direct quenching in the tip is much higher than the direct quenching in the substrate. We adopt four tips with diffierent apex radii, i.e., 1 nm, 5 nm, 10 nm, 20 nm. When the apex size is small, the frequency dependent enhancement factor from the SPPs contribution has a pronounced peak at 1.55 eV, however, as the radius increases, the peak of enhancement factor in the high frequency region appears, the 1.55 eV peak becomes less dominated. This phenomenon can be attributed to the change of tip shape, in the form of mode coupling. Our results also show a relationship between the direct quenching in the substrate and in the tip. With the larger radius of apex, the ratio of these two part of energy approaches 1, which indicate that the energy distribution of direct quenching is sensitive to the shape of the tip-substrate gap.
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73
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Fregoni J, Granucci G, Coccia E, Persico M, Corni S. Manipulating azobenzene photoisomerization through strong light-molecule coupling. Nat Commun 2018; 9:4688. [PMID: 30409994 PMCID: PMC6224570 DOI: 10.1038/s41467-018-06971-y] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Accepted: 10/04/2018] [Indexed: 11/09/2022] Open
Abstract
The formation of hybrid light–molecule states (polaritons) offers a new strategy to manipulate the photochemistry of molecules. To fully exploit its potential, one needs to build a toolbox of polaritonic phenomenologies that supplement those of standard photochemistry. By means of a state-of-the-art computational photochemistry approach extended to the strong-coupling regime, here we disclose various mechanisms peculiar of polaritonic chemistry: coherent population oscillations between polaritons, quenching by trapping in dead-end polaritonic states and the alteration of the photochemical reaction pathway and quantum yields. We focus on azobenzene photoisomerization, that encompasses the essential features of complex photochemical reactions such as the presence of conical intersections and reaction coordinates involving multiple internal modes. In the strong coupling regime, a polaritonic conical intersection arises and we characterize its role in the photochemical process. Our chemically detailed simulations provide a framework to rationalize how the strong coupling impacts the photochemistry of realistic molecules. Manipulation of the photochemistry of molecules is traditionally achieved through synthetic chemical modifications. Here the authors use computational photochemistry to show how to control azobenzene photoisomerization through hybrid light–molecule states (polaritons).
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Affiliation(s)
- J Fregoni
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, University of Modena and Reggio Emilia, I-41125, Modena, Italy.,Istituto Nanoscienze, Consiglio Nazionale delle Ricerche CNR-NANO, I-41125, Modena, Italy
| | - G Granucci
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, I-56124, Pisa, Italy.
| | - E Coccia
- Dipartimento di Scienze Chimiche, University of Padova, I-35131, Padova, Italy
| | - M Persico
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, I-56124, Pisa, Italy
| | - S Corni
- Istituto Nanoscienze, Consiglio Nazionale delle Ricerche CNR-NANO, I-41125, Modena, Italy. .,Dipartimento di Scienze Chimiche, University of Padova, I-35131, Padova, Italy.
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74
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Muller EA, Pollard B, Bechtel HA, Adato R, Etezadi D, Altug H, Raschke MB. Nanoimaging and Control of Molecular Vibrations through Electromagnetically Induced Scattering Reaching the Strong Coupling Regime. ACS PHOTONICS 2018; 5:3594-3600. [PMID: 30828589 PMCID: PMC6390704 DOI: 10.1021/acsphotonics.8b00425] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Indexed: 05/27/2023]
Abstract
Optical resonators can enhance light-matter interaction, modify intrinsic molecular properties such as radiative emission rates, and create new molecule-photon hybrid quantum states. To date, corresponding implementations are based on electronic transitions in the visible spectral region with large transition dipoles yet hampered by fast femtosecond electronic dephasing. In contrast, coupling molecular vibrations with their weaker dipoles to infrared optical resonators has been less explored, despite long-lived coherences with 2 orders of magnitude longer dephasing times. Here, we achieve excitation of molecular vibrations through configurable optical interactions of a nanotip with an infrared resonant nanowire that supports tunable bright and nonradiative dark modes. The resulting antenna-vibrational coupling up to 47 ± 5 cm-1 exceeds the intrinsic dephasing rate of the molecular vibration, leading to hybridization and mode splitting. We observe nanotip-induced quantum interference of vibrational excitation pathways in spectroscopic nanoimaging, which we model classically as plasmonic electromagnetically induced scattering as the phase-controlled extension of the classical analogue of electromagnetically induced transparency and absorption. Our results present a new regime of IR spectroscopy for applications of vibrational coherence from quantum computing to optical control of chemical reactions.
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Affiliation(s)
- Eric A. Muller
- Department
of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder, Colorado 80309, United States
| | - Benjamin Pollard
- Department
of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder, Colorado 80309, United States
| | - Hans A. Bechtel
- Advanced
Light Source Division, Lawrence Berkeley
National Laboratory, Berkeley, California 94720, United States
| | - Ronen Adato
- Departments
of Electrical and Computer Engineering and Photonics Center, Boston University, Boston, Massachusetts 02215, United States
| | - Dordaneh Etezadi
- Institute
of Bioengineering, École Polytechnique
Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Hatice Altug
- Institute
of Bioengineering, École Polytechnique
Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Markus B. Raschke
- Department
of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder, Colorado 80309, United States
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75
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Tiguntseva EY, Baranov DG, Pushkarev AP, Munkhbat B, Komissarenko F, Franckevičius M, Zakhidov AA, Shegai T, Kivshar YS, Makarov SV. Tunable Hybrid Fano Resonances in Halide Perovskite Nanoparticles. NANO LETTERS 2018; 18:5522-5529. [PMID: 30071168 DOI: 10.1021/acs.nanolett.8b01912] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Halide perovskites are known to support excitons at room temperatures with high quantum yield of luminescence that make them attractive for all-dielectric resonant nanophotonics and meta-optics. Here we report the observation of broadly tunable Fano resonances in halide perovskite nanoparticles originating from the coupling of excitons to the Mie resonances excited in the nanoparticles. Signatures of the photon-exciton (" hybrid") Fano resonances are observed in dark-field spectra of isolated nanoparticles, and also in the extinction spectra of aperiodic lattices of such nanoparticles. In the latter case, chemical tunability of the exciton resonance allows reversible tuning of the Fano resonance across the 100 nm bandwidth in the visible frequency range, providing a novel approach to control optical properties of perovskite nanostructures. The proposed method of chemical tuning paves the way to an efficient control of emission properties of on-chip-integrated light-emitting nanoantennas.
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Affiliation(s)
| | - Denis G Baranov
- ITMO University , Saint Petersburg 197101 , Russia
- Department of Physics , Chalmers University of Technology , 412 96 Gothenburg , Sweden
| | | | - Battulga Munkhbat
- Department of Physics , Chalmers University of Technology , 412 96 Gothenburg , Sweden
| | | | | | - Anvar A Zakhidov
- ITMO University , Saint Petersburg 197101 , Russia
- University of Texas at Dallas , Richardson , Texas 75080 , United States
| | - Timur Shegai
- Department of Physics , Chalmers University of Technology , 412 96 Gothenburg , Sweden
| | - Yuri S Kivshar
- ITMO University , Saint Petersburg 197101 , Russia
- Nonlinear Physics Centre , Australian National University , Canberra , ACT 2601 , Australia
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76
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Doppagne B, Chong MC, Bulou H, Boeglin A, Scheurer F, Schull G. Electrofluorochromism at the single-molecule level. Science 2018; 361:251-255. [DOI: 10.1126/science.aat1603] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 05/17/2018] [Indexed: 11/02/2022]
Abstract
The interplay between the oxidation state and the optical properties of molecules is important for applications in displays, sensors, and molecular-based memories. The fundamental mechanisms occurring at the level of a single molecule have been difficult to probe. We used a scanning tunneling microscope (STM) to characterize and control the fluorescence of a single zinc-phthalocyanine radical cation adsorbed on a sodium chloride–covered gold (111) sample. The neutral and oxidized states of the molecule were identified on the basis of their fluorescence spectra, which revealed very different emission energies and vibronic fingerprints. The emission of the charged molecule was controlled by tuning the thickness of the insulator and the plasmons localized at the apex of the STM tip. In addition, subnanometric variations of the tip position were used to investigate the charging and electroluminescence mechanisms.
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Affiliation(s)
- Benjamin Doppagne
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - Michael C. Chong
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - Hervé Bulou
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - Alex Boeglin
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - Fabrice Scheurer
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - Guillaume Schull
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
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77
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Kröger J, Doppagne B, Scheurer F, Schull G. Fano Description of Single-Hydrocarbon Fluorescence Excited by a Scanning Tunneling Microscope. NANO LETTERS 2018; 18:3407-3413. [PMID: 29719154 DOI: 10.1021/acs.nanolett.8b00304] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The detection of fluorescence with submolecular resolution enables the exploration of spatially varying photon yields and vibronic properties at the single-molecule level. By placing individual polycyclic aromatic hydrocarbon molecules into the plasmon cavity formed by the tip of a scanning tunneling microscope and a NaCl-covered Ag(111) surface, molecular light emission spectra are obtained that unravel vibrational progression. In addition, light spectra unveil a signature of the molecule even when the tunneling current is injected well separated from the molecular emitter. This signature exhibits a distance-dependent Fano profile that reflects the subtle interplay between inelastic tunneling electrons, the molecular exciton and localized plasmons in at-distance as well as on-molecule fluorescence. The presented findings open the path to luminescence of a different class of molecules than investigated before and contribute to the understanding of single-molecule luminescence at surfaces in a unified picture.
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Affiliation(s)
- Jörg Kröger
- Institut de Physique et Chimie des Matériaux de Strasbourg , Université de Strasbourg, CNRS, IPCMS, UMR 7504 , F-67000 Strasbourg , France
| | - Benjamin Doppagne
- Institut de Physique et Chimie des Matériaux de Strasbourg , Université de Strasbourg, CNRS, IPCMS, UMR 7504 , F-67000 Strasbourg , France
| | - Fabrice Scheurer
- Institut de Physique et Chimie des Matériaux de Strasbourg , Université de Strasbourg, CNRS, IPCMS, UMR 7504 , F-67000 Strasbourg , France
| | - Guillaume Schull
- Institut de Physique et Chimie des Matériaux de Strasbourg , Université de Strasbourg, CNRS, IPCMS, UMR 7504 , F-67000 Strasbourg , France
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78
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Rosławska A, Merino P, Große C, Leon CC, Gunnarsson O, Etzkorn M, Kuhnke K, Kern K. Single Charge and Exciton Dynamics Probed by Molecular-Scale-Induced Electroluminescence. NANO LETTERS 2018; 18:4001-4007. [PMID: 29799760 DOI: 10.1021/acs.nanolett.8b01489] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Excitons and their constituent charge carriers play the central role in electroluminescence mechanisms determining the ultimate performance of organic optoelectronic devices. The involved processes and their dynamics are often studied with time-resolved techniques limited by spatial averaging that obscures the properties of individual electron-hole pairs. Here, we overcome this limit and characterize single charge and exciton dynamics at the nanoscale by using time-resolved scanning tunneling microscopy-induced luminescence (TR-STML) stimulated with nanosecond voltage pulses. We use isolated defects in C60 thin films as a model system into which we inject single charges and investigate the formation dynamics of a single exciton. Tunable hole and electron injection rates are obtained from a kinetic model that reproduces the measured electroluminescent transients. These findings demonstrate that TR-STML can track dynamics at the quantum limit of single charge injection and can be extended to other systems and materials important for nanophotonic devices.
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Affiliation(s)
- Anna Rosławska
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
| | - Pablo Merino
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
| | - Christoph Große
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
| | - Christopher C Leon
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
| | - Olle Gunnarsson
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
| | - Markus Etzkorn
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
| | - Klaus Kuhnke
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
| | - Klaus Kern
- Max Planck Institute for Solid State Research , Heisenbergstraße 1 , 70569 Stuttgart , Germany
- Institut de Physique , École Polytechnique Fédérale de Lausanne , 1015 Lausanne , Switzerland
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79
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Wang HF, Chen G, Li XG, Dong ZC. Role of nanocavity plasmons in tunneling electron induced light emission on and near a molecule. CHINESE J CHEM PHYS 2018. [DOI: 10.1063/1674-0068/31/cjcp1802024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Hui-fang Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Gong Chen
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
- School of Physics and Engineering, Zhengzhou University, Zhengzhou 450052, China
| | - Xiao-guang Li
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
| | - Zhen-chao Dong
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
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80
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Konečná A, Neuman T, Aizpurua J, Hillenbrand R. Surface-Enhanced Molecular Electron Energy Loss Spectroscopy. ACS NANO 2018; 12:4775-4786. [PMID: 29641179 DOI: 10.1021/acsnano.8b01481] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Electron energy loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM) is becoming an important technique in spatially resolved spectral characterization of optical and vibrational properties of matter at the nanoscale. EELS has played a significant role in understanding localized polaritonic excitations in nanoantennas and also allows for studying molecular excitations in nanoconfined samples. Here we theoretically describe the interaction of a localized electron beam with molecule-covered polaritonic nanoantennas, and propose the concept of surface-enhanced molecular EELS exploiting the electromagnetic coupling between the nanoantenna and the molecular sample. Particularly, we study plasmonic and infrared phononic antennas covered by molecular layers, exhibiting either an excitonic or vibrational response. We demonstrate that EEL spectra of these molecule-antenna coupled systems exhibit Fano-like or strong coupling features, similar to the ones observed in far-field optical and infrared spectroscopy. EELS offers the advantage to acquire spectral information with nanoscale spatial resolution, and importantly, to control the antenna-molecule coupling on demand. Considering ongoing instrumental developments, EELS in STEM shows the potential to become a powerful tool for fundamental studies of molecules that are naturally or intentionally located on nanostructures supporting localized plasmon or phonon polaritons. Surface-enhanced EELS might also enable STEM-EELS applications such as remote- and thus damage-free-sensing of the excitonic and vibrational response of molecules, quantum dots, or 2D materials.
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Affiliation(s)
- Andrea Konečná
- Materials Physics Center, CSIC-UPV/EHU , Donostia-San Sebastián , 20018 , Spain
| | - Tomáš Neuman
- Materials Physics Center, CSIC-UPV/EHU , Donostia-San Sebastián , 20018 , Spain
| | - Javier Aizpurua
- Materials Physics Center, CSIC-UPV/EHU , Donostia-San Sebastián , 20018 , Spain
- Donostia International Physics Center DIPC , Donostia-San Sebastián , 20018 , Spain
| | - Rainer Hillenbrand
- IKERBASQUE, Basque Foundation for Science , Bilbao , 48013 , Spain
- CIC NanoGUNE and UPV/EHU , Donostia-San Sebastián , 20018 , Spain
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81
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Merino P, Rosławska A, Große C, Leon CC, Kuhnke K, Kern K. Bimodal exciton-plasmon light sources controlled by local charge carrier injection. SCIENCE ADVANCES 2018; 4:eaap8349. [PMID: 29806018 PMCID: PMC5969822 DOI: 10.1126/sciadv.aap8349] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 04/12/2018] [Indexed: 05/24/2023]
Abstract
Electrical charges can generate photon emission in nanoscale quantum systems by two independent mechanisms. First, radiative recombination of pairs of oppositely charged carriers generates sharp excitonic lines. Second, coupling between currents and collective charge oscillations results in broad plasmonic bands. Both luminescence modes can be simultaneously generated upon charge carrier injection into thin C60 crystallites placed in the plasmonic nanocavity of a scanning tunneling microscope (STM). Using the sharp tip of the STM as a subnanometer-precise local electrode, we show that the two types of electroluminescence are induced by two separate charge transport channels. Holes injected into the valence band promote exciton generation, whereas electrons extracted from the conduction band cause plasmonic luminescence. The different dynamics of the two mechanisms permit controlling their relative contribution in the combined bimodal emission. Exciton recombination prevails for low charge injection rates, whereas plasmon decay outshines for high tunneling currents. The continuous transition between both regimes is described by a rate model characterizing emission dynamics on the nanoscale. Our work provides the basis for developing blended exciton-plasmon light sources with advanced functionalities.
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Affiliation(s)
- Pablo Merino
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Anna Rosławska
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Christoph Große
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Christopher C. Leon
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Klaus Kuhnke
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Klaus Kern
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
- Institut de Physique, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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82
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Tang J, Xia J, Fang M, Bao F, Cao G, Shen J, Evans J, He S. Selective far-field addressing of coupled quantum dots in a plasmonic nanocavity. Nat Commun 2018; 9:1705. [PMID: 29704002 PMCID: PMC5924364 DOI: 10.1038/s41467-018-04077-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 04/03/2018] [Indexed: 01/16/2023] Open
Abstract
Plasmon–emitter hybrid nanocavity systems exhibit strong plasmon–exciton interactions at the single-emitter level, showing great potential as testbeds and building blocks for quantum optics and informatics. However, reported experiments involve only one addressable emitting site, which limits their relevance for many fundamental questions and devices involving interactions among emitters. Here we open up this critical degree of freedom by demonstrating selective far-field excitation and detection of two coupled quantum dot emitters in a U-shaped gold nanostructure. The gold nanostructure functions as a nanocavity to enhance emitter interactions and a nanoantenna to make the emitters selectively excitable and detectable. When we selectively excite or detect either emitter, we observe photon emission predominantly from the target emitter with up to 132-fold Purcell-enhanced emission rate, indicating individual addressability and strong plasmon–exciton interactions. Our work represents a step towards a broad class of plasmonic devices that will enable faster, more compact optics, communication and computation. Plasmonic nanostructures can tailor excitation and emission for quantum emitters, but generally only for a single emitter. In this work, the authors selectively excite and detect one out of two quantum dots coupled to a deep-subwavelength cavity composed of three gold nanorods assembled into a U-shape.
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Affiliation(s)
- Jianwei Tang
- Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation, National Engineering Research Center of Optical Instrumentation, JORCEP, College of Optical Science and Engineering, Zhejiang University, 310058, Hangzhou, China
| | - Juan Xia
- Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation, National Engineering Research Center of Optical Instrumentation, JORCEP, College of Optical Science and Engineering, Zhejiang University, 310058, Hangzhou, China
| | - Maodong Fang
- Centre for Optical and Electromagnetic Research, ZJU-SCNU Joint Center of Photonics, South China Academy of Advanced Optoelectronics, South China Normal University, 510006, Guangzhou, China
| | - Fanglin Bao
- Centre for Optical and Electromagnetic Research, ZJU-SCNU Joint Center of Photonics, South China Academy of Advanced Optoelectronics, South China Normal University, 510006, Guangzhou, China
| | - Guanjun Cao
- Centre for Optical and Electromagnetic Research, ZJU-SCNU Joint Center of Photonics, South China Academy of Advanced Optoelectronics, South China Normal University, 510006, Guangzhou, China
| | - Jianqi Shen
- Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation, National Engineering Research Center of Optical Instrumentation, JORCEP, College of Optical Science and Engineering, Zhejiang University, 310058, Hangzhou, China
| | - Julian Evans
- Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation, National Engineering Research Center of Optical Instrumentation, JORCEP, College of Optical Science and Engineering, Zhejiang University, 310058, Hangzhou, China
| | - Sailing He
- Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation, National Engineering Research Center of Optical Instrumentation, JORCEP, College of Optical Science and Engineering, Zhejiang University, 310058, Hangzhou, China. .,Centre for Optical and Electromagnetic Research, ZJU-SCNU Joint Center of Photonics, South China Academy of Advanced Optoelectronics, South China Normal University, 510006, Guangzhou, China. .,Department of Electromagnetic Engineering, School of Electrical Engineering, Royal Institute of Technology, S-100 44, Stockholm, Sweden.
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83
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Neuman T, Esteban R, Casanova D, García-Vidal FJ, Aizpurua J. Coupling of Molecular Emitters and Plasmonic Cavities beyond the Point-Dipole Approximation. NANO LETTERS 2018; 18:2358-2364. [PMID: 29522686 DOI: 10.1021/acs.nanolett.7b05297] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
As the size of a molecular emitter becomes comparable to the dimensions of a nearby optical resonator, the standard approach that considers the emitter to be a point-like dipole breaks down. By adoption of a quantum description of the electronic transitions of organic molecular emitters, coupled to a plasmonic electromagnetic field, we are able to accurately calculate the position-dependent coupling strength between a plasmon and an emitter. The spatial distribution of excitonic and photonic quantum states is found to be a key aspect in determining the dynamics of molecular emission in ultrasmall cavities both in the weak and strong coupling regimes. Moreover, we show that the extreme localization of plasmonic fields leads to the selection rule breaking of molecular excitations.
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Affiliation(s)
- Tomáš Neuman
- Donostia International Physics Center (DIPC) , 20018 San Sebastián-Donostia , Spain
| | - Ruben Esteban
- Donostia International Physics Center (DIPC) , 20018 San Sebastián-Donostia , Spain
- IKERBASQUE, Basque Foundation for Science , Maria Diaz de Haro 3 , 48013 Bilbao , Spain
| | - David Casanova
- Donostia International Physics Center (DIPC) , 20018 San Sebastián-Donostia , Spain
- IKERBASQUE, Basque Foundation for Science , Maria Diaz de Haro 3 , 48013 Bilbao , Spain
| | - Francisco J García-Vidal
- Donostia International Physics Center (DIPC) , 20018 San Sebastián-Donostia , Spain
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC) , Universidad Autónoma de Madrid , E-28049 Madrid , Spain
| | - Javier Aizpurua
- Donostia International Physics Center (DIPC) , 20018 San Sebastián-Donostia , Spain
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84
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Autore M, Li P, Dolado I, Alfaro-Mozaz FJ, Esteban R, Atxabal A, Casanova F, Hueso LE, Alonso-González P, Aizpurua J, Nikitin AY, Vélez S, Hillenbrand R. Boron nitride nanoresonators for phonon-enhanced molecular vibrational spectroscopy at the strong coupling limit. LIGHT, SCIENCE & APPLICATIONS 2018; 7:17172. [PMID: 30839544 PMCID: PMC6060053 DOI: 10.1038/lsa.2017.172] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 12/06/2017] [Accepted: 12/07/2017] [Indexed: 05/05/2023]
Abstract
Enhanced light-matter interactions are the basis of surface-enhanced infrared absorption (SEIRA) spectroscopy, and conventionally rely on plasmonic materials and their capability to focus light to nanoscale spot sizes. Phonon polariton nanoresonators made of polar crystals could represent an interesting alternative, since they exhibit large quality factors, which go far beyond those of their plasmonic counterparts. The recent emergence of van der Waals crystals enables the fabrication of high-quality nanophotonic resonators based on phonon polaritons, as reported for the prototypical infrared-phononic material hexagonal boron nitride (h-BN). In this work we use, for the first time, phonon-polariton-resonant h-BN ribbons for SEIRA spectroscopy of small amounts of organic molecules in Fourier transform infrared spectroscopy. Strikingly, the interaction between phonon polaritons and molecular vibrations reaches experimentally the onset of the strong coupling regime, while numerical simulations predict that vibrational strong coupling can be fully achieved. Phonon polariton nanoresonators thus could become a viable platform for sensing, local control of chemical reactivity and infrared quantum cavity optics experiments.
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Affiliation(s)
- Marta Autore
- CIC nanoGUNE, Donostia-San Sebastián 20018, Spain
| | - Peining Li
- CIC nanoGUNE, Donostia-San Sebastián 20018, Spain
| | - Irene Dolado
- CIC nanoGUNE, Donostia-San Sebastián 20018, Spain
| | | | - Ruben Esteban
- Donostia International Physics Center (DIPC), Donostia-San Sebastián 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Spain
| | | | - Fèlix Casanova
- CIC nanoGUNE, Donostia-San Sebastián 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Spain
| | - Luis E Hueso
- CIC nanoGUNE, Donostia-San Sebastián 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Spain
| | | | - Javier Aizpurua
- Donostia International Physics Center (DIPC), Donostia-San Sebastián 20018, Spain
- Centro de Física de Materiales (MPC, CSIC-UPV/EHU), Donostia-San Sebastián 20018, Spain
| | - Alexey Y Nikitin
- Donostia International Physics Center (DIPC), Donostia-San Sebastián 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Spain
| | - Saül Vélez
- CIC nanoGUNE, Donostia-San Sebastián 20018, Spain
- Current address: Department of Materials, ETH Zürich, Zürich 8093, Switzerland
| | - Rainer Hillenbrand
- IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Spain
- CIC nanoGUNE and UPV/EHU, Donostia-San Sebastián 20018, Spain
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85
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Urbieta M, Barbry M, Zhang Y, Koval P, Sánchez-Portal D, Zabala N, Aizpurua J. Atomic-Scale Lightning Rod Effect in Plasmonic Picocavities: A Classical View to a Quantum Effect. ACS NANO 2018; 12:585-595. [PMID: 29298379 DOI: 10.1021/acsnano.7b07401] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Plasmonic gaps are known to produce nanoscale localization and enhancement of optical fields, providing small effective mode volumes of about a few hundred nm3. Atomistic quantum calculations based on time-dependent density functional theory reveal the effect of subnanometric localization of electromagnetic fields due to the presence of atomic-scale features at the interfaces of plasmonic gaps. Using a classical model, we explain this as a nonresonant lightning rod effect at the atomic scale that produces an extra enhancement over that of the plasmonic background. The near-field distribution of atomic-scale hot spots around atomic features is robust against dynamical screening and spill-out effects and follows the potential landscape determined by the electron density around the atomic sites. A detailed comparison of the field distribution around atomic hot spots from full quantum atomistic calculations and from the local classical approach considering the geometrical profile of the atoms' electronic density validates the use of a classical framework to determine the effective mode volume in these extreme subnanometric optical cavities. This finding is of practical importance for the community of surface-enhanced molecular spectroscopy and quantum nanophotonics, as it provides an adequate description of the local electromagnetic fields around atomic-scale features with use of simplified classical methods.
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Affiliation(s)
- Mattin Urbieta
- Materials Physics Center (CSIC-UPV/EHU) and Donostia International Physics Center (DIPC) , Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
- Department of Electricity and Electronics, FCT-ZTF, UPV-EHU , 48080 Bilbao, Spain
| | - Marc Barbry
- Materials Physics Center (CSIC-UPV/EHU) and Donostia International Physics Center (DIPC) , Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
| | - Yao Zhang
- Materials Physics Center (CSIC-UPV/EHU) and Donostia International Physics Center (DIPC) , Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
| | - Peter Koval
- Materials Physics Center (CSIC-UPV/EHU) and Donostia International Physics Center (DIPC) , Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
| | - Daniel Sánchez-Portal
- Materials Physics Center (CSIC-UPV/EHU) and Donostia International Physics Center (DIPC) , Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
| | - Nerea Zabala
- Materials Physics Center (CSIC-UPV/EHU) and Donostia International Physics Center (DIPC) , Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
- Department of Electricity and Electronics, FCT-ZTF, UPV-EHU , 48080 Bilbao, Spain
| | - Javier Aizpurua
- Materials Physics Center (CSIC-UPV/EHU) and Donostia International Physics Center (DIPC) , Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
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86
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Ding SJ, Li X, Nan F, Zhong YT, Zhou L, Xiao X, Wang QQ, Zhang Z. Strongly Asymmetric Spectroscopy in Plasmon-Exciton Hybrid Systems due to Interference-Induced Energy Repartitioning. PHYSICAL REVIEW LETTERS 2017; 119:177401. [PMID: 29219439 DOI: 10.1103/physrevlett.119.177401] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Indexed: 06/07/2023]
Abstract
Recent intense effort has been devoted to exploring different manifestations of resonant excitations of strongly coupled plasmons and excitons, but so far such studies have been limited to situations where the Fano- or Rabi-type spectra are largely symmetric at zero detuning. Using a newly developed full quantum mechanical model, here we reveal the existence of a highly asymmetric spectroscopic regime for both the Rabi splitting and transparency dip. The asymmetric nature is inherently tied to the non-negligible exciton absorbance and is caused by substantial interference-induced energy repartitioning of the resonance peaks. This theoretical framework can be exploited to reveal the quantum behaviors of the two excitation entities with varying mutual coupling strengths in both linear and nonlinear regimes. We also use prototypical systems of rhodamine molecules strongly coupled with AuAg alloyed nanoparticles and well-devised control experiments to demonstrate the validity and tunability of the energy repartitioning and correlated electronic state occupations, as captured by the variations in the asymmetric spectroscopy and corresponding nonlinear absorption coefficient as a function of the Au:Ag ratio. The present study helps to substantially enrich our microscopic understanding of strongly coupled plasmon-exciton systems.
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Affiliation(s)
- Si-Jing Ding
- Department of Physics, Wuhan University, Wuhan, Hubei 430072, China
| | - Xiaoguang Li
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
| | - Fan Nan
- Department of Physics, Wuhan University, Wuhan, Hubei 430072, China
| | - Yu-Ting Zhong
- Department of Physics, Wuhan University, Wuhan, Hubei 430072, China
| | - Li Zhou
- Department of Physics, Wuhan University, Wuhan, Hubei 430072, China
| | - Xudong Xiao
- Department of Physics, The Chinese University of Hong Kong, Shatin, New Territory 999077, Hong Kong, China
| | - Qu-Quan Wang
- Department of Physics, Wuhan University, Wuhan, Hubei 430072, China
- Institute for Advanced Study, Wuhan University, Wuhan, Hubei 430072, China
| | - Zhenyu Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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