1
|
Wang Z, Kalathingal V, Trushin M, Liu J, Wang J, Guo Y, Özyilmaz B, Nijhuis CA, Eda G. Upconversion electroluminescence in 2D semiconductors integrated with plasmonic tunnel junctions. NATURE NANOTECHNOLOGY 2024; 19:993-999. [PMID: 38641642 DOI: 10.1038/s41565-024-01650-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 03/13/2024] [Indexed: 04/21/2024]
Abstract
Plasmonic tunnel junctions are a unique electroluminescent system in which light emission occurs via an interplay between tunnelling electrons and plasmonic fields instead of electron-hole recombination as in conventional light-emitting diodes. It was previously shown that placing luminescent molecules in the tunneling pathway of nanoscopic tunnel junctions results in peculiar upconversion electroluminescence where the energy of emitted photons exceeds that of excitation electrons. Here we report the observation of upconversion electroluminescence in macroscopic van der Waals plasmonic tunnel junctions comprising gold and few-layer graphene electrodes separated by a ~2-nm-thick hexagonal boron nitride tunnel barrier and a monolayer semiconductor. We find that the semiconductor ground exciton emission is triggered at excitation electron energies lower than the semiconductor optical gap. Interestingly, this upconversion is reached in devices operating at a low conductance (<10-6 S) and low power density regime (<102 W cm-2), defying explanation through existing proposed mechanisms. By examining the scaling relationship between plasmonic and excitonic emission intensities, we elucidate the role of inelastic electron tunnelling dipoles that induce optically forbidden transitions in the few-layer graphene electrode and ultrafast hot carrier transfer across the van der Waals interface.
Collapse
Affiliation(s)
- Zhe Wang
- Department of Chemistry, National University of Singapore, Singapore, Singapore
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Vijith Kalathingal
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
- Department of Physics, Kannur University, Swami Anandatheertha Campus-Payyanur, Kannur, India
| | - Maxim Trushin
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Material Science and Engineering, National University of Singapore, Singapore, Singapore
| | - Jiawei Liu
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Junyong Wang
- CAS Key Laboratory of Nano-Bio Interface and Key Laboratory of Nanodevices and Applications, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Yongxin Guo
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Barbaros Özyilmaz
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Material Science and Engineering, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Christian A Nijhuis
- Hybrid Materials for Opto-Electronics Group, Department of Molecules and Materials, MESA+ Institute for Nanotechnology, Molecules Center and Center for Brain-Inspired Nano Systems, Faculty of Science and Technology, University of Twente, Enschede, the Netherlands.
| | - Goki Eda
- Department of Chemistry, National University of Singapore, Singapore, Singapore.
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore.
- Department of Physics, National University of Singapore, Singapore, Singapore.
| |
Collapse
|
2
|
Zhang X, Li Z, Ji S, Xu W, Chen L, Xiao Z, Liu J, Hong W. Plasmon-Molecule Interactions in Single-Molecule Junctions. Chempluschem 2024; 89:e202300556. [PMID: 38050755 DOI: 10.1002/cplu.202300556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 11/16/2023] [Accepted: 11/28/2023] [Indexed: 12/06/2023]
Abstract
Single-molecule optoelectronics offers opportunities for advancing integrated photonics and electronics, which also serves as a tool to elucidate the underlying mechanism of light-matter interaction. Plasmonics, which plays pivotal role in the interaction of photons and matter, have became an emerging area. A comprehensive understanding of the plasmonic excitation and modulation mechanisms within single-molecule junctions (SMJs) lays the foundation for optoelectronic devices. Consequently, this review primarily concentrates on illuminating the fundamental principles of plasmonics within SMJs, delving into their research methods and modulation factors of plasmon-exciton. Moreover, we underscore the interaction phenomena within SMJs, including the enhancement of molecular fluorescence by plasmonics, Fano resonance and Rabi splitting caused by the interaction of plasmon-exciton. Finally, by emphasizing the potential applications of plasmonics within SMJs, such as their roles in optical tweezers, single-photon sources, super-resolution imaging, and chemical reactions, we elucidate the future prospects and current challenges in this domain.
Collapse
Affiliation(s)
- Xiangui Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, Fujian, 361005, China
| | - Zhengyu Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, Fujian, 361005, China
| | - Shurui Ji
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, Fujian, 361005, China
| | - Wei Xu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, Fujian, 361005, China
| | - Lijue Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, Fujian, 361005, China
| | - Zongyuan Xiao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, Fujian, 361005, China
| | - Junyang Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, Fujian, 361005, China
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, Fujian, 361005, China
| |
Collapse
|
3
|
Krukowski P, Hattori T, Akai-Kasaya M, Saito A, Osuga H, Kuwahara Y. Light Emission from M-Type Enantiomer of 2,13-bis(hydroxymethyl)[7]-thiaheterohelicene Molecules Adsorbed on Au(111) and C 60/Au(111) Surfaces Investigated by STM-LE. Int J Mol Sci 2022; 23:ijms232315399. [PMID: 36499724 PMCID: PMC9737099 DOI: 10.3390/ijms232315399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 11/26/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
Light emission from the M-type enantiomer of a helicene derivative (2,13-bis(hydroxymethyl)[7]-thiaheterohelicene) adsorbed on the clean Au(111) and the C60-covered Au(111) surfaces were investigated by tunneling-current-induced light-emission technique. Plasmon-originated light emission was observed on the helicence/Au(111) surface and it was strongly suppressed on the area where the helicene molecules were adsorbed at the edges of the Au(111) terraces. To avoid luminescence quenching of excited helicene molecules and to suppress strong plasmon light emission from the Au(111) surface, C60 layers were used as decoupling buffer layers between helicene molecules and the Au(111) surface. Helicene molecules were adsorbed preferentially on the Au(111) surface rather than on the C60 buffer layers due to the small interaction of the molecules and C60 islands. This fact motivated us to deposit a multilayer of helicene molecules onto the C60 layers grown on the Au(111) surface, leading to the fact that the helicene/C60 multilayer showed strong luminescence with the molecules character. We consider that such strong light emission from the multilayer of helicene molecules has a plasmon origin strongly modulated by the molecular electronic states of (M)-[7]TH-diol molecules.
Collapse
Affiliation(s)
- Paweł Krukowski
- Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of Lodz, 90–236 Łódź, Poland
- Correspondence:
| | - Takuma Hattori
- Department of Precision Engineering, Graduate School of Engineering, Osaka University, Suita 565–0871, Japan
| | - Megumi Akai-Kasaya
- Department of Precision Engineering, Graduate School of Engineering, Osaka University, Suita 565–0871, Japan
| | - Akira Saito
- Department of Precision Engineering, Graduate School of Engineering, Osaka University, Suita 565–0871, Japan
| | - Hideji Osuga
- Department of Materials Science and Chemistry, Faculty of Systems Engineering, Wakayama University, Wakayama 640-8510, Japan
| | - Yuji Kuwahara
- Department of Precision Engineering, Graduate School of Engineering, Osaka University, Suita 565–0871, Japan
| |
Collapse
|
4
|
Li P, Zhou L, Zhao C, Ju H, Gao Q, Si W, Cheng L, Hao J, Li M, Chen Y, Jia C, Guo X. Single-molecule nano-optoelectronics: insights from physics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:086401. [PMID: 35623319 DOI: 10.1088/1361-6633/ac7401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
Single-molecule optoelectronic devices promise a potential solution for miniaturization and functionalization of silicon-based microelectronic circuits in the future. For decades of its fast development, this field has made significant progress in the synthesis of optoelectronic materials, the fabrication of single-molecule devices and the realization of optoelectronic functions. On the other hand, single-molecule optoelectronic devices offer a reliable platform to investigate the intrinsic physical phenomena and regulation rules of matters at the single-molecule level. To further realize and regulate the optoelectronic functions toward practical applications, it is necessary to clarify the intrinsic physical mechanisms of single-molecule optoelectronic nanodevices. Here, we provide a timely review to survey the physical phenomena and laws involved in single-molecule optoelectronic materials and devices, including charge effects, spin effects, exciton effects, vibronic effects, structural and orbital effects. In particular, we will systematically summarize the basics of molecular optoelectronic materials, and the physical effects and manipulations of single-molecule optoelectronic nanodevices. In addition, fundamentals of single-molecule electronics, which are basic of single-molecule optoelectronics, can also be found in this review. At last, we tend to focus the discussion on the opportunities and challenges arising in the field of single-molecule optoelectronics, and propose further potential breakthroughs.
Collapse
Affiliation(s)
- Peihui Li
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Li Zhou
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Cong Zhao
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Hongyu Ju
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
- School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, People's Republic of China
| | - Qinghua Gao
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Wei Si
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Li Cheng
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Jie Hao
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Mengmeng Li
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Yijian Chen
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
| | - Chuancheng Jia
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
- Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Center, College of Chemistry and Molecular Engineering, Peking University, 292 Chengfu Road, Haidian District, Beijing 100871, People's Republic of China
| | - Xuefeng Guo
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, People's Republic of China
- Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Center, College of Chemistry and Molecular Engineering, Peking University, 292 Chengfu Road, Haidian District, Beijing 100871, People's Republic of China
| |
Collapse
|
5
|
Liu Y, Bian Y, Zhang Y, Hang C, Zhang X, Lou S, Jin Q. Fluorescence of CoTPP Mediated by the Plasmon-Exciton Coupling Effect in the Tunneling Junction. J Phys Chem Lett 2021; 12:5349-5356. [PMID: 34076440 DOI: 10.1021/acs.jpclett.1c01123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
CoTPP, as a common hypsoporphyrin, is usually not a luminescent molecule because of the open-shell Co ion. In this paper, well-defined multilayer CoTPP molecules self-assembled on Au(111) surface are characterized layer by layer with scanning tunneling microscope (STM) induced luminescence. By using the highly localized STM tunneling current, we not only investigate the influence of bias polarity on the amplitude of distinct plasmonic emission resulted from the interaction between the metal substrate and the metal ions but also first obtain the light emission from the hypsoporphyrins in the tunneling junction. The density-matrix method and the combined approach of classical electrodynamics and first-principles calculation are used to explain the mechanism of the light emission. These findings may expand the underlying physics of plasmon-exciton coupling in STM nanocavity and reveal a new possible path to overcome the fluorescent potential of hypsoporphyrins by the intense localized electric fields.
Collapse
Affiliation(s)
- Yiting Liu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
| | - Yajie Bian
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
| | - Yuyi Zhang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
| | - Chao Hang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
| | - Xiaolei Zhang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, P. R. China
| | - Shitao Lou
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
| | - Qingyuan Jin
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
- Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China
| |
Collapse
|
6
|
Lebedev DV, Shkoldin VA, Mozharov AM, Permyakov DV, Dvoretckaia LN, Bogdanov AA, Samusev AK, Golubok AO, Mukhin IS. Scanning Tunneling Microscopy-Induced Light Emission and I( V) Study of Optical Near-Field Properties of Single Plasmonic Nanoantennas. J Phys Chem Lett 2021; 12:501-507. [PMID: 33373245 DOI: 10.1021/acs.jpclett.0c03039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Electrically driven plasmonic nanoantennas can be integrated as a local source of the optical signal of advanced photonic schemes for on-chip data processing. The inelastic electron tunneling provides the photon generation or launch of surface plasmon waves. This process can be enhanced by the local density of optical states of nanoantennas. In this paper, we used scanning tunnel microscopy-induced light emission to probe the local optoelectronic properties of single gold nanodiscs. The electromagnetic field distribution in the vicinity of plasmonic structures was investigated with high spatial resolution. The obtained photon maps reveal the nonuniform distribution of electromagnetic near-fields, which is consistent with nanoantenna optical modes. Also, the analysis of derived I(V) curves showed a direct correlation between the nanoantenna optical states and the appearance of features on current-voltage characteristics.
Collapse
Affiliation(s)
- Denis V Lebedev
- Saint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034, Russia
- Institute for Analytical Instrumentation RAS, 26 Rizhskii pr., St. Petersburg 190103, Russia
- St. Petersburg Academic University, 8/3 Khlopina str., St. Petersburg 194021, Russia
| | - Vitaliy A Shkoldin
- St. Petersburg Academic University, 8/3 Khlopina str., St. Petersburg 194021, Russia
- ITMO University, 9 Kronverksky pr., St. Petersburg 197101, Russia
| | - Alexey M Mozharov
- St. Petersburg Academic University, 8/3 Khlopina str., St. Petersburg 194021, Russia
| | | | - Lilia N Dvoretckaia
- St. Petersburg Academic University, 8/3 Khlopina str., St. Petersburg 194021, Russia
| | | | - Anton K Samusev
- ITMO University, 9 Kronverksky pr., St. Petersburg 197101, Russia
| | - Alexander O Golubok
- Institute for Analytical Instrumentation RAS, 26 Rizhskii pr., St. Petersburg 190103, Russia
| | - Ivan S Mukhin
- St. Petersburg Academic University, 8/3 Khlopina str., St. Petersburg 194021, Russia
- ITMO University, 9 Kronverksky pr., St. Petersburg 197101, Russia
| |
Collapse
|
7
|
Schuler B, Cochrane KA, Kastl C, Barnard ES, Wong E, Borys NJ, Schwartzberg AM, Ogletree DF, de Abajo FJG, Weber-Bargioni A. Electrically driven photon emission from individual atomic defects in monolayer WS 2. SCIENCE ADVANCES 2020; 6:eabb5988. [PMID: 32938664 PMCID: PMC7494346 DOI: 10.1126/sciadv.abb5988] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 07/31/2020] [Indexed: 05/22/2023]
Abstract
Quantum dot-like single-photon sources in transition metal dichalcogenides (TMDs) exhibit appealing quantum optical properties but lack a well-defined atomic structure and are subject to large spectral variability. Here, we demonstrate electrically stimulated photon emission from individual atomic defects in monolayer WS2 and directly correlate the emission with the local atomic and electronic structure. Radiative transitions are locally excited by sequential inelastic electron tunneling from a metallic tip into selected discrete defect states in the WS2 bandgap. Coupling to the optical far field is mediated by tip plasmons, which transduce the excess energy into a single photon. The applied tip-sample voltage determines the transition energy. Atomically resolved emission maps of individual point defects closely resemble electronic defect orbitals, the final states of the optical transitions. Inelastic charge carrier injection into localized defect states of two-dimensional materials provides a powerful platform for electrically driven, broadly tunable, atomic-scale single-photon sources.
Collapse
Affiliation(s)
- Bruno Schuler
- Molecular Foundry, Lawrence Berkeley National Laboratory, CA 94720, USA.
| | | | - Christoph Kastl
- Molecular Foundry, Lawrence Berkeley National Laboratory, CA 94720, USA
- Walter-Schottky-Institut and Physik-Department, Technical University of Munich, Garching 85748, Germany
| | - Edward S Barnard
- Molecular Foundry, Lawrence Berkeley National Laboratory, CA 94720, USA
| | - Edward Wong
- Molecular Foundry, Lawrence Berkeley National Laboratory, CA 94720, USA
| | - Nicholas J Borys
- Molecular Foundry, Lawrence Berkeley National Laboratory, CA 94720, USA
- Department of Physics, Montana State University, Bozeman, MT 59717, USA
| | | | - D Frank Ogletree
- Molecular Foundry, Lawrence Berkeley National Laboratory, CA 94720, USA
| | - F Javier García de Abajo
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain.
- ICREA-Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
| | | |
Collapse
|
8
|
Unveiling the radiative local density of optical states of a plasmonic nanocavity by STM. Nat Commun 2020; 11:1021. [PMID: 32094339 PMCID: PMC7039974 DOI: 10.1038/s41467-020-14827-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 01/29/2020] [Indexed: 11/27/2022] Open
Abstract
Atomically-sharp tips in close proximity of metal surfaces create plasmonic nanocavities supporting both radiative (bright) and non-radiative (dark) localized surface plasmon modes. Disentangling their respective contributions to the total density of optical states remains a challenge. Electroluminescence due to tunnelling through the tip-substrate gap could allow the identification of the radiative component, but this information is inherently convoluted with that of the electronic structure of the system. In this work, we present a fully experimental procedure to eliminate the electronic-structure factors from the scanning tunnelling microscope luminescence spectra by confronting them with spectroscopic information extracted from elastic current measurements. Comparison against electromagnetic calculations demonstrates that this procedure allows the characterization of the meV shifts experienced by the nanocavity plasmonic modes under atomic-scale gap size changes. Therefore, the method gives access to the frequency-dependent radiative Purcell enhancement that a microscopic light emitter would undergo when placed at such nanocavity. Disentangling the radiative and non-radiative plasmon mode contributions to the total photonic density of states is a challenge. Here, the authors report a procedure to eliminate the electronic-structure factors from scanning tunnelling microscope luminescence spectra to isolate the radiative component.
Collapse
|
9
|
Parzefall M, Novotny L. Optical antennas driven by quantum tunneling: a key issues review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:112401. [PMID: 31491785 DOI: 10.1088/1361-6633/ab4239] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Analogous to radio- and microwave antennas, optical nanoantennas are devices that receive and emit radiation at optical frequencies. Until recently, the realization of electrically driven optical antennas was an outstanding challenge in nanophotonics. In this review we discuss and analyze recent reports in which quantum tunneling-specifically inelastic electron tunneling-is harnessed as a means to convert electrical energy into photons, mediated by optical antennas. To aid this analysis we introduce the fundamentals of optical antennas and inelastic electron tunneling. Our discussion is focused on recent progress in the field and on future directions and opportunities.
Collapse
|
10
|
Queck F, Albrecht F, Mutombo P, Krejci O, Jelínek P, McLean A, Repp J. Interface dipoles of Ir(ppy) 3 on Cu(111). NANOSCALE 2019; 11:12695-12703. [PMID: 31240287 DOI: 10.1039/c9nr00934e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The interplay of adsorption geometry and interface dipoles of the transition-metal complex Ir(ppy)3 on Cu(111) was studied using low-temperature scanning probe microscopy and density-functional-theory calculations. We find that the orientation of the molecule's intrinsic dipole moment with respect to the surface has a strong influence on the total energy of the different configurations, where the most stable one has the molecular dipole moment pointing out of the surface plane along the surface normal. Adsorption-induced redistribution of charges results in an additional dipole moment that also points out of the surface plane for all configurations. Submolecularly resolved maps of the resulting local contact potential difference suggest that any in-plane dipole moment is very effectively screened.
Collapse
Affiliation(s)
- Fabian Queck
- Department of Physics, University of Regensburg, 93053 Regensburg, Germany.
| | - Florian Albrecht
- Department of Physics, University of Regensburg, 93053 Regensburg, Germany.
| | - Pingo Mutombo
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, CZ-162000, Prague, Czech Republic
| | - Ondrej Krejci
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, CZ-162000, Prague, Czech Republic and Department of Applied Physics, Aalto University, P.O. Box 11000, FI-00076 Aalto, Finland
| | - Pavel Jelínek
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, CZ-162000, Prague, Czech Republic and Regional Centre of Advanced Technologies and Materials, Palacký University, ŝlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Alastair McLean
- Department of Physics, Engineering Physics and Astronomy, Queen's University, Kingston, ON, CanadaK7L3N6.
| | - Jascha Repp
- Department of Physics, University of Regensburg, 93053 Regensburg, Germany.
| |
Collapse
|
11
|
Merino P, Rosławska A, Leon CC, Grewal A, Große C, González C, Kuhnke K, Kern K. A Single Hydrogen Molecule as an Intensity Chopper in an Electrically Driven Plasmonic Nanocavity. NANO LETTERS 2019; 19:235-241. [PMID: 30558427 PMCID: PMC6517280 DOI: 10.1021/acs.nanolett.8b03753] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Photon statistics is a powerful tool for characterizing the emission dynamics of nanoscopic systems and their photophysics. Recent advances that combine correlation spectroscopy with scanning tunneling microscopy induced luminescence (STML) have allowed the measurement of the emission dynamics from individual molecules and defects, demonstrating their nature as single-photon emitters. The application of correlation spectroscopy to the analysis of the dynamics of a well-characterized adsorbate system in an ultrahigh vacuum remained to be demonstrated. Here, we combine single-photon time correlations with STML to measure the dynamics of individual H2 molecules between a gold tip and an Au(111) surface. An adsorbed H2 molecule performs recurrent excursions below the tip apex. We use the fact that the presence of the H2 molecule in the junction modifies plasmon emission to study the adsorbate dynamics. Using the H2 molecule as a chopper for STM-induced optical emission intensity, we demonstrate bunching in the plasmonic photon train in a single measurement over 6 orders of magnitude in the time domain (from microseconds to seconds) that takes only a few seconds. Our findings illustrate the power of using photon statistics to measure the diffusion dynamics of adsorbates with STML.
Collapse
Affiliation(s)
- P. Merino
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
- Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz 3, 28049, Madrid, Spain
- Instituto de Física Fundamental, CSIC, Serrano 121, 28006, Madrid, Spain
- Corresponding author.
| | - A. Rosławska
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - C. C. Leon
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - A. Grewal
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - C. Große
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - C. González
- Departamento de Física Teorica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Facultad de Ciencias, Universidad Autonoma de Madrid, 28049 Madrid, Spain
| | - K. Kuhnke
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - K. Kern
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
- Institut de Physique, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| |
Collapse
|
12
|
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.
Collapse
|
13
|
Möller TB, Ganser A, Kratt M, Dickreuter S, Waitz R, Scheer E, Boneberg J, Leiderer P. Fast quantitative optical detection of heat dissipation by surface plasmon polaritons. NANOSCALE 2018; 10:11894-11900. [PMID: 29897094 DOI: 10.1039/c8nr02489h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Heat management at the nanoscale is an issue of increasing importance. In optoelectronic devices the transport and decay of plasmons contribute to the dissipation of heat. By comparison of experimental data and simulations we demonstrate that it is possible to gain quantitative information about excitation, propagation and decay of surface plasmon polaritons (SPPs) in a thin gold stripe supported by a silicon membrane. The temperature-dependent optical transmissivity of the membrane is used to determine the temperature distribution around the metal stripe with high spatial and temporal resolution. This method is complementary to techniques where the propagation of SPPs is monitored optically, and provides additional information which is not readily accessible by other means. In particular, we demonstrate that the thermal conductivity of the membrane can also be derived from our analysis. The results presented here show the high potential of this tool for heat management studies in nanoscale devices.
Collapse
Affiliation(s)
- Thomas B Möller
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
Yu A, Li S, Wang H, Chen S, Wu R, Ho W. Visualization of Nanoplasmonic Coupling to Molecular Orbital in Light Emission Induced by Tunneling Electrons. NANO LETTERS 2018; 18:3076-3080. [PMID: 29660286 DOI: 10.1021/acs.nanolett.8b00613] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The coupling between localized plasmon and molecular orbital in the light emission from a metallic nanocavity has been directly detected and imaged with sub-0.1 nm resolution. The light emission intensity was enhanced when the energy difference between the tunneling electrons and the lowest unoccupied molecular orbital (LUMO) of an azulene molecule matches the energy of a plasmon mode of the nanocavity defined by the Ag-tip and Ag (110) substrate of a scanning tunneling microscope (STM). The spatially resolved image of the light emission intensity matches the spatial distribution of the LUMO obtained by scanning tunneling spectroscopy (STS) and density functional theory (DFT) calculations. Our results highlight the near-field coupling of a molecular orbital to the radiative decay of a plasmonic excitation in a confined nanoscale junction.
Collapse
Affiliation(s)
- Arthur Yu
- Department of Physics and Astronomy , University of California , Irvine , California 92697-4575 , United States
| | - Shaowei Li
- Department of Physics and Astronomy , University of California , Irvine , California 92697-4575 , United States
| | - Hui Wang
- Department of Physics and Astronomy , University of California , Irvine , California 92697-4575 , United States
| | - Siyu Chen
- Department of Physics and Astronomy , University of California , Irvine , California 92697-4575 , United States
| | - Ruqian Wu
- Department of Physics and Astronomy , University of California , Irvine , California 92697-4575 , United States
| | - W Ho
- Department of Physics and Astronomy , University of California , Irvine , California 92697-4575 , United States
- Department of Chemistry , University of California , Irvine , California 92697-2025 , United States
| |
Collapse
|
16
|
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.
Collapse
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
| |
Collapse
|
17
|
Zhao M, Almarzouqi F, Duverger E, Sonnet P, Dujardin G, Mayne AJ. Sub-molecular spectroscopy and temporary molecular charging of Ni-phthalocyanine on graphene with STM. Phys Chem Chem Phys 2018; 20:19507-19514. [DOI: 10.1039/c8cp02113a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this study, the self-assembled molecular network and electronic properties of Ni-phthalocyanine (NiPc) molecules on monolayer graphene (MLG)/6H-SiC(0001) were studied by room temperature Scanning Tunnelling Microscopy (STM) and Density Functional Theory (DFT) calculations.
Collapse
Affiliation(s)
- Mali Zhao
- Institut des Sciences Moléculaires d’Orsay
- CNRS UMR 8214
- Université Paris-Sud
- Université Paris-Saclay
- 91405 Orsay
| | - Faisal Almarzouqi
- Institut des Sciences Moléculaires d’Orsay
- CNRS UMR 8214
- Université Paris-Sud
- Université Paris-Saclay
- 91405 Orsay
| | - Eric Duverger
- Institut FEMTO-ST
- Université de Franche-Comté
- CNRS UMR 6174
- Besançon
- France
| | - Philippe Sonnet
- Institut de Science des Matériaux de Mulhouse IS2M
- CNRS UMR 7361
- Université de Haute Alsace
- 68093 Mulhouse
- France
| | - Gérald Dujardin
- Institut des Sciences Moléculaires d’Orsay
- CNRS UMR 8214
- Université Paris-Sud
- Université Paris-Saclay
- 91405 Orsay
| | - Andrew J. Mayne
- Institut des Sciences Moléculaires d’Orsay
- CNRS UMR 8214
- Université Paris-Sud
- Université Paris-Saclay
- 91405 Orsay
| |
Collapse
|
18
|
Imada H, Miwa K, Imai-Imada M, Kawahara S, Kimura K, Kim Y. Single-Molecule Investigation of Energy Dynamics in a Coupled Plasmon-Exciton System. PHYSICAL REVIEW LETTERS 2017; 119:013901. [PMID: 28731759 DOI: 10.1103/physrevlett.119.013901] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Indexed: 05/12/2023]
Abstract
We investigate the near-field interaction between an isolated free-base phthalocyanine molecule and a plasmon localized in the gap between an NaCl-covered Ag(111) surface and the tip apex of a scanning tunneling microscope. When the tip is located in the close proximity of the molecule, asymmetric dips emerge in the broad luminescence spectrum of the plasmon generated by the tunneling current. The origin of the dips is explained by energy transfer between the plasmon and molecular excitons and a quantum mechanical interference effect, where molecular vibrations provide additional degrees of freedom in the dynamic process.
Collapse
Affiliation(s)
- Hiroshi Imada
- Surface and Interface Science Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Kuniyuki Miwa
- Surface and Interface Science Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Miyabi Imai-Imada
- Surface and Interface Science Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Advanced Materials Science, Graduate School of Frontier Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8651, Japan
| | - Shota Kawahara
- Surface and Interface Science Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Advanced Materials Science, Graduate School of Frontier Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8651, Japan
| | - Kensuke Kimura
- Surface and Interface Science Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Advanced Materials Science, Graduate School of Frontier Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8651, Japan
| | - Yousoo Kim
- Surface and Interface Science Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| |
Collapse
|
19
|
Kalathingal V, Dawson P, Mitra J. Scanning tunnelling microscope light emission: Finite temperature current noise and over cut-off emission. Sci Rep 2017; 7:3530. [PMID: 28615660 PMCID: PMC5471255 DOI: 10.1038/s41598-017-03766-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 05/04/2017] [Indexed: 11/09/2022] Open
Abstract
The spectral distribution of light emitted from a scanning tunnelling microscope junction not only bears its intrinsic plasmonic signature but is also imprinted with the characteristics of optical frequency fluc- tuations of the tunnel current. Experimental spectra from gold-gold tunnel junctions are presented that show a strong bias (V b ) dependence, curiously with emission at energies higher than the quantum cut-off (eV b ); a component that decays monotonically with increasing bias. The spectral evolution is explained by developing a theoretical model for the power spectral density of tunnel current fluctuations, incorporating finite temperature contribution through consideration of the quantum transport in the system. Notably, the observed decay of the over cut-off emission is found to be critically associated with, and well explained in terms of the variation in junction conductance with V b . The investigation highlights the scope of plasmon-mediated light emission as a unique probe of high frequency fluctuations in electronic systems that are fundamental to the electrical generation and control of plasmons.
Collapse
Affiliation(s)
- Vijith Kalathingal
- School of Physics, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, 695016, India.
| | - Paul Dawson
- Centre for Nanostructured Media, Queen's University, Belfast, BT7 1NN, United Kingdom
| | - J Mitra
- School of Physics, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, 695016, India.
| |
Collapse
|
20
|
Kuhnke K, Große C, Merino P, Kern K. Atomic-Scale Imaging and Spectroscopy of Electroluminescence at Molecular Interfaces. Chem Rev 2017; 117:5174-5222. [DOI: 10.1021/acs.chemrev.6b00645] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Klaus Kuhnke
- Max-Planck-Institut für Festkörperforschung, Stuttgart 70569, Germany
| | - Christoph Große
- Max-Planck-Institut für Festkörperforschung, Stuttgart 70569, Germany
| | - Pablo Merino
- Max-Planck-Institut für Festkörperforschung, Stuttgart 70569, Germany
| | - Klaus Kern
- Max-Planck-Institut für Festkörperforschung, Stuttgart 70569, Germany
- Institut de Physique, Ecole Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
| |
Collapse
|
21
|
Große C, Merino P, Rosławska A, Gunnarsson O, Kuhnke K, Kern K. Submolecular Electroluminescence Mapping of Organic Semiconductors. ACS NANO 2017; 11:1230-1237. [PMID: 28085244 DOI: 10.1021/acsnano.6b08471] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The electroluminescence of organic films is the central aspect in organic light emitting diodes (OLEDs) and widely used in current display technology. However, its spatial variation on the molecular scale is essentially unexplored. Here, we address this issue by using scanning tunneling microscopy (STM) and present an in-depth study of the electroluminescence from thin C60 films (<10 monolayers) on Ag(111) and Au(111) surfaces. Similar to an OLED, the metal substrate and STM tip inject complementary charge carriers that may recombine within the molecular film; however, the atomically defined charge injection by the tip enables mapping of the local electroluminescence down to the submolecular scale. We show that the radiative recombination in solid C60 is restricted to various structural defects, whose emission characteristics can be addressed individually. The emission fine structure reveals a coupling to Jahn-Teller active vibrational modes of C60, which implies that its parity-forbidden lowest singlet transition becomes locally allowed at the emission centers. At lateral distances of a few nanometers, only a weak emission from tip-induced plasmons is detectable. Their excitation evidences the injection of both charge carrier types and confirms that they are unable to recombine radiatively at positions far from structural defects. Finally, we demonstrate that the molecular orbital pattern visible in electroluminescence maps enables an unambiguous discrimination between the intrinsic radiative recombination of electron-hole pairs in the organic film and the technique-related emission of tip-induced plasmons. This capability is essential to consolidate STM as a tool to explore the light generation from organic films on the nanoscale.
Collapse
Affiliation(s)
- Christoph Große
- Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Pablo Merino
- Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Anna Rosławska
- Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Olle Gunnarsson
- Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Klaus Kuhnke
- Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Klaus Kern
- Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany
- Institut de Physique, École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| |
Collapse
|
22
|
Rogez B, Cao S, Dujardin G, Comtet G, Moal EL, Mayne A, Boer-Duchemin E. The mechanism of light emission from a scanning tunnelling microscope operating in air. NANOTECHNOLOGY 2016; 27:465201. [PMID: 27734808 DOI: 10.1088/0957-4484/27/46/465201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The scanning tunnelling microscope (STM) may be used as a low-energy, electrical nanosource of surface plasmon polaritons and light. In this article, we demonstrate that the optimum mode of operation of the STM for maximum photon emission is completely different in air than in vacuum. To this end, we investigate the emission of photons, the variation in the relative tip-sample distance and the measured current as a function of time for an STM operating in air. Contrary to the case of an STM operating in vacuum, the measured current between the tip and sample for an STM in air is very unstable (rapidly fluctuating in time) when the applied voltage between the tip and sample is in the ∼1.5-3 V range (i.e., in the energy range of visible photons). The photon emission occurs in short (50 μs) bursts when the STM tip is closest to the sample. The current instabilities are shown to be a key ingredient for producing intense light emission from an STM operating in air (photon emission rate several orders of magnitude higher than for stable current). These results are explained in terms of the interplay between the tunnel current and the electrochemical current in the ubiquitous thin water layer that exists when working in air.
Collapse
Affiliation(s)
- B Rogez
- Department of Cellular Physiology, Ludwig-Maximilians-Universität, Munich, Germany
| | | | | | | | | | | | | |
Collapse
|
23
|
Braun K, Wang X, Kern AM, Adler H, Peisert H, Chassé T, Zhang D, Meixner AJ. Superluminescence from an optically pumped molecular tunneling junction by injection of plasmon induced hot electrons. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2015; 6:1100-6. [PMID: 26171286 PMCID: PMC4463973 DOI: 10.3762/bjnano.6.111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 04/02/2015] [Indexed: 05/26/2023]
Abstract
Here, we demonstrate a bias-driven superluminescent point light-source based on an optically pumped molecular junction (gold substrate/self-assembled molecular monolayer/gold tip) of a scanning tunneling microscope, operating at ambient conditions and providing almost three orders of magnitude higher electron-to-photon conversion efficiency than electroluminescence induced by inelastic tunneling without optical pumping. A positive, steadily increasing bias voltage induces a step-like rise of the Stokes shifted optical signal emitted from the junction. This emission is strongly attenuated by reversing the applied bias voltage. At high bias voltage, the emission intensity depends non-linearly on the optical pump power. The enhanced emission can be modelled by rate equations taking into account hole injection from the tip (anode) into the highest occupied orbital of the closest substrate-bound molecule (lower level) and radiative recombination with an electron from above the Fermi level (upper level), hence feeding photons back by stimulated emission resonant with the gap mode. The system reflects many essential features of a superluminescent light emitting diode.
Collapse
Affiliation(s)
- Kai Braun
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Xiao Wang
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Andreas M Kern
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Hilmar Adler
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Heiko Peisert
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Thomas Chassé
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Dai Zhang
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Alfred J Meixner
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| |
Collapse
|
24
|
Chen G, Li XG, Zhang ZY, Dong ZC. Molecular hot electroluminescence due to strongly enhanced spontaneous emission rates in a plasmonic nanocavity. NANOSCALE 2015; 7:2442-2449. [PMID: 25565003 DOI: 10.1039/c4nr06519k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have recently demonstrated anomalous relaxationless hot electroluminescence from molecules in the tunnel junction of a scanning tunneling microscope [Dong et al., Nat. Photonics, 2010, 4, 50]. In the present paper, based on physically realistic parameters, we aim to unravel the underlying physical mechanism using a multiscale modeling approach that combines classical generalized Mie theory with the quantum master equation. We find that the nanocavity-plasmon-tuned spontaneous emission rate plays a crucial role in shaping the spectral profile. In particular, on resonance, the radiative decay rate can be enhanced by three-to-five orders of magnitude, which enables the radiative process to occur on the lifetime scale of picoseconds and become competitive to the vibrational relaxation. Such a large Purcell effect opens up new emission channels to generate the hot luminescence that arises directly from higher vibronic levels of the molecular excited state. We also stress that the critical role of resonant plasmonic nanocavities in tunneling electron induced molecular luminescence is to enhance the spontaneous radiative decay through plasmon enhanced vacuum fluctuations rather than to generate an efficient plasmon stimulated emission process. This improved understanding has been partly overlooked in previous studies but is believed to be very important for further developments of molecular plasmonics and optoelectronics.
Collapse
Affiliation(s)
- Gong Chen
- International Center for Quantum Design of Functional Materials, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | | | | | | |
Collapse
|
25
|
Teulle A, Bosman M, Girard C, Gurunatha KL, Li M, Mann S, Dujardin E. Multimodal plasmonics in fused colloidal networks. NATURE MATERIALS 2015; 14:87-94. [PMID: 25344783 PMCID: PMC4270737 DOI: 10.1038/nmat4114] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Accepted: 09/18/2014] [Indexed: 05/18/2023]
Abstract
Harnessing the optical properties of noble metals down to the nanometre scale is a key step towards fast and low-dissipative information processing. At the 10-nm length scale, metal crystallinity and patterning as well as probing of surface plasmon properties must be controlled with a challenging high level of precision. Here, we demonstrate that ultimate lateral confinement and delocalization of surface plasmon modes are simultaneously achieved in extended self-assembled networks comprising linear chains of partially fused gold nanoparticles. The spectral and spatial distributions of the surface plasmon modes associated with the colloidal superstructures are evidenced by performing monochromated electron energy-loss spectroscopy with a nanometre-sized electron probe. We prepare the metallic bead strings by electron-beam-induced interparticle fusion of nanoparticle networks. The fused superstructures retain the native morphology and crystallinity but develop very low-energy surface plasmon modes that are capable of supporting long-range and spectrally tunable propagation in nanoscale waveguides.
Collapse
Affiliation(s)
- Alexandre Teulle
- CEMES CNRS UPR 8011, 29 rue J. Marvig, 31055 Toulouse Cedex 4, France
| | - Michel Bosman
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, 117602 Singapore
- Correspondence and requests for materials should be addressed to E.D. or M. B. ,
| | - Christian Girard
- CEMES CNRS UPR 8011, 29 rue J. Marvig, 31055 Toulouse Cedex 4, France
| | | | - Mei Li
- Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol, Cantocks Close, Bristol BS81TS, United Kingdom
| | - Stephen Mann
- Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol, Cantocks Close, Bristol BS81TS, United Kingdom
| | - Erik Dujardin
- CEMES CNRS UPR 8011, 29 rue J. Marvig, 31055 Toulouse Cedex 4, France
- Correspondence and requests for materials should be addressed to E.D. or M. B. ,
| |
Collapse
|
26
|
Große C, Kabakchiev A, Lutz T, Froidevaux R, Schramm F, Ruben M, Etzkorn M, Schlickum U, Kuhnke K, Kern K. Dynamic control of plasmon generation by an individual quantum system. NANO LETTERS 2014; 14:5693-5697. [PMID: 25181332 DOI: 10.1021/nl502413k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Controlling light on the nanoscale in a similar way as electric currents has the potential to revolutionize the exchange and processing of information. Although light can be guided on this scale by coupling it to plasmons, that is, collective electron oscillations in metals, their local electronic control remains a challenge. Here, we demonstrate that an individual quantum system is able to dynamically gate the electrical plasmon generation. Using a single molecule in a double tunnel barrier between two electrodes we show that this gating can be exploited to monitor fast changes of the quantum system itself and to realize a single-molecule plasmon-generating field-effect transistor operable in the gigahertz range. This opens new avenues toward atomic scale quantum interfaces bridging nanoelectronics and nanophotonics.
Collapse
Affiliation(s)
- Christoph Große
- Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Chen P, Wang W, Lin N, Du S. Manipulating photon emission efficiency with local electronic states in a tunneling gap. OPTICS EXPRESS 2014; 22:8234-8242. [PMID: 24718199 DOI: 10.1364/oe.22.008234] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We demonstrate manipulation of photon emission efficiency in a tunneling gap by tuning the rates of elastic and inelastic electron tunneling processes with local electronic states. The artificial local electronic states are created by a scanning tunneling microscope tip on a CuN nanoisland grown on a Cu(100) surface at cryogenic temperature. These local electronic states can either enhance or suppress the excitation of tip-induced surface plasmon modes at specific bias voltages, and thus the induced photon emission rates. A theoretical model quantitatively analyzing inelastic and elastic tunneling processes associated with characteristic electronic states shows good agreement with experiments. We also show that tip-induced photon emission measurement can be used for probing the electronic states in the tunneling gap.
Collapse
|