1
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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 2024:10.1038/s41565-024-01650-0. [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.
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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.
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2
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Rosławska A, Kaiser K, Romeo M, Devaux E, Scheurer F, Berciaud S, Neuman T, Schull G. Submolecular-scale control of phototautomerization. NATURE NANOTECHNOLOGY 2024:10.1038/s41565-024-01622-4. [PMID: 38413791 DOI: 10.1038/s41565-024-01622-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 01/29/2024] [Indexed: 02/29/2024]
Abstract
Optically activated reactions initiate biological processes such as photosynthesis or vision, but can also control polymerization, catalysis or energy conversion. Methods relying on the manipulation of light at macroscopic and mesoscopic scales are used to control on-surface photochemistry, but do not offer atomic-scale control. Here we take advantage of the confinement of the electromagnetic field at the apex of a scanning tunnelling microscope tip to drive the phototautomerization of a free-base phthalocyanine with submolecular precision. We can control the reaction rate and the relative tautomer population through a change in the laser excitation wavelength or through the tip position. Atomically resolved tip-enhanced photoluminescence spectroscopy and hyperspectral mapping unravel an excited-state mediated process, which is quantitatively supported by a comprehensive theoretical model combining ab initio calculations with a parametric open-quantum-system approach. Our experimental strategy may allow insights in other photochemical reactions and proof useful to control complex on-surface reactions.
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Affiliation(s)
- Anna Rosławska
- Université de Strasbourg, CNRS, IPCMS, Strasbourg, France.
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
| | - Katharina Kaiser
- Université de Strasbourg, CNRS, IPCMS, Strasbourg, France
- 4th Physical Institute - Solids and Nanostructures, Georg-August-Universität Göttingen, Göttingen, Germany
| | | | - Eloïse Devaux
- Université de Strasbourg, CNRS, ISIS, Strasbourg, France
| | | | | | - Tomáš Neuman
- Institut des Sciences Moléculaires d'Orsay (ISMO), UMR 8214, CNRS, Université Paris-Saclay, Orsay, France.
- Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic.
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3
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Luo Y, Kong FF, Tian XJ, Yu YJ, Jing SH, Zhang C, Chen G, Zhang Y, Zhang Y, Li XG, Zhang ZY, Dong ZC. Anomalously bright single-molecule upconversion electroluminescence. Nat Commun 2024; 15:1677. [PMID: 38395971 PMCID: PMC10891098 DOI: 10.1038/s41467-024-45450-5] [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: 08/20/2023] [Accepted: 01/23/2024] [Indexed: 02/25/2024] Open
Abstract
Efficient upconversion electroluminescence is highly desirable for a broad range of optoelectronic applications, yet to date, it has been reported only for ensemble systems, while the upconversion electroluminescence efficiency remains very low for single-molecule emitters. Here we report on the observation of anomalously bright single-molecule upconversion electroluminescence, with emission efficiencies improved by more than one order of magnitude over previous studies, and even stronger than normal-bias electroluminescence. Intuitively, the improvement is achieved via engineering the energy-level alignments at the molecule-substrate interface so as to activate an efficient spin-triplet mediated upconversion electroluminescence mechanism that only involves pure carrier injection steps. We further validate the intuitive picture with the construction of delicate electroluminescence diagrams for the excitation of single-molecule electroluminescence, allowing to readily identify the prerequisite conditions for producing efficient upconversion electroluminescence. These findings provide deep insights into the microscopic mechanism of single-molecule upconversion electroluminescence and organic electroluminescence in general.
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Affiliation(s)
- Yang Luo
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Fan-Fang Kong
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Xiao-Jun Tian
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Yun-Jie Yu
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Shi-Hao Jing
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Chao Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Gong Chen
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
| | - Yang Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China
| | - Yao Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China
| | - Xiao-Guang Li
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, China
| | - Zhen-Yu Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China
| | - Zhen-Chao Dong
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China.
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4
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Coane CV, Romanelli M, Dall'Osto G, Di Felice R, Corni S. Unraveling the mechanism of tip-enhanced molecular energy transfer. Commun Chem 2024; 7:32. [PMID: 38360897 PMCID: PMC10869822 DOI: 10.1038/s42004-024-01118-1] [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: 07/04/2023] [Accepted: 02/01/2024] [Indexed: 02/17/2024] Open
Abstract
Electronic Energy Transfer (EET) between chromophores is fundamental in many natural light-harvesting complexes, serving as a critical step for solar energy funneling in photosynthetic plants and bacteria. The complicated role of the environment in mediating this process in natural architectures has been addressed by recent scanning tunneling microscope experiments involving EET between two molecules supported on a solid substrate. These measurements demonstrated that EET in such conditions has peculiar features, such as a steep dependence on the donor-acceptor distance, reminiscent of a short-range mechanism more than of a Förster-like process. By using state of the art hybrid ab initio/electromagnetic modeling, here we provide a comprehensive theoretical analysis of tip-enhanced EET. In particular, we show that this process can be understood as a complex interplay of electromagnetic-based molecular plasmonic processes, whose result may effectively mimic short range effects. Therefore, the established identification of an exponential decay with Dexter-like effects does not hold for tip-enhanced EET, and accurate electromagnetic modeling is needed to identify the EET mechanism.
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Affiliation(s)
- Colin V Coane
- Department of Chemical Sciences, University of Padova, via Marzolo 1, Padova, Italy
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, 90089, USA
| | - Marco Romanelli
- Department of Chemical Sciences, University of Padova, via Marzolo 1, Padova, Italy
| | - Giulia Dall'Osto
- Department of Chemical Sciences, University of Padova, via Marzolo 1, Padova, Italy
| | - Rosa Di Felice
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, 90089, USA.
- CNR Institute of Nanoscience, via Campi 213/A, Modena, Italy.
| | - Stefano Corni
- Department of Chemical Sciences, University of Padova, via Marzolo 1, Padova, Italy.
- CNR Institute of Nanoscience, via Campi 213/A, Modena, Italy.
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5
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Doležal J, Sagwal A, de Campos Ferreira RC, Švec M. Single-Molecule Time-Resolved Spectroscopy in a Tunable STM Nanocavity. NANO LETTERS 2024; 24:1629-1634. [PMID: 38286028 PMCID: PMC10853955 DOI: 10.1021/acs.nanolett.3c04314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/23/2024] [Accepted: 01/23/2024] [Indexed: 01/31/2024]
Abstract
Spontaneous fluorescence rates of single-molecule emitters are typically on the order of nanoseconds. However, coupling them with plasmonic nanostructures can substantially increase their fluorescence yields. The confinement between a tip and sample in a scanning tunneling microscope creates a tunable nanocavity, an ideal platform for exploring the yields and excitation decay rates of single-molecule emitters, depending on their coupling strength to the nanocavity. With such a setup, we determine the excitation lifetimes from the direct time-resolved measurements of phthalocyanine fluorescence decays, decoupled from the metal substrates by ultrathin NaCl layers. We find that when the tip is approached to single molecules, their lifetimes are reduced to the picosecond range due to the effect of coupling with the tip-sample nanocavity. On the other hand, ensembles of the adsorbed molecules measured without the nanocavity manifest nanosecond-range lifetimes. This approach overcomes the drawbacks associated with the estimation of lifetimes for single molecules from their respective emission line widths.
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Affiliation(s)
- Jiří Doležal
- Institute
of Physics, Czech Academy of Sciences; Cukrovarnická 10/112, CZ16200 Praha 6, Czech Republic
| | - Amandeep Sagwal
- Institute
of Physics, Czech Academy of Sciences; Cukrovarnická 10/112, CZ16200 Praha 6, Czech Republic
- Faculty
of Mathematics and Physics, Charles University; Ke Karlovu 3, CZ12116 Praha 2, Czech Republic
| | | | - Martin Švec
- Institute
of Physics, Czech Academy of Sciences; Cukrovarnická 10/112, CZ16200 Praha 6, Czech Republic
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Flemingovo náměstí 542/2, CZ16000 Praha 6, Czech Republic
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6
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Kaiser K, Lieske LA, Repp J, Gross L. Charge-state lifetimes of single molecules on few monolayers of NaCl. Nat Commun 2023; 14:4988. [PMID: 37591847 PMCID: PMC10435478 DOI: 10.1038/s41467-023-40692-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 08/02/2023] [Indexed: 08/19/2023] Open
Abstract
In molecular tunnel junctions, where the molecule is decoupled from the electrodes by few-monolayers-thin insulating layers, resonant charge transport takes place by sequential charge transfer to and from the molecule which implies transient charging of the molecule. The corresponding charge state transitions, which involve tunneling through the insulating decoupling layers, are crucial for understanding electrically driven processes such as electroluminescence or photocurrent generation in such a geometry. Here, we use scanning tunneling microscopy to investigate the decharging of single ZnPc and H2Pc molecules through NaCl films of 3 to 5 monolayers thickness on Cu(111) and Au(111). To this end, we approach the tip to the molecule at resonant tunnel conditions up to a regime where charge transport is limited by tunneling through the NaCl film. The resulting saturation of the tunnel current is a direct measure of the lifetimes of the anionic and cationic states, i.e., the molecule's charge-state lifetime, and thus provides a means to study charge dynamics and, thereby, exciton dynamics. Comparison of anion and cation lifetimes on different substrates reveals the critical role of the level alignment with the insulator's conduction and valence band, and the metal-insulator interface state.
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Affiliation(s)
- Katharina Kaiser
- IBM Research Europe-Zurich, Säumerstrasse 4, 8803, Rüschlikon, Switzerland.
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000, Strasbourg, France.
| | | | - Jascha Repp
- Department of Physics, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Leo Gross
- IBM Research Europe-Zurich, Säumerstrasse 4, 8803, Rüschlikon, Switzerland.
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7
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Yu YJ, Kuai Y, Fan YT, Zhu LF, Kong FF, Tian XJ, Jing SH, Zhang L, Zhang DG, Zhang Y, Zhang Y, Dong ZC. Back focal plane imaging for light emission from a tunneling junction in a low-temperature ultrahigh-vacuum scanning tunneling microscope. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:063703. [PMID: 37862523 DOI: 10.1063/5.0147401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 06/04/2023] [Indexed: 10/22/2023]
Abstract
We report the design and realization of the back focal plane (BFP) imaging for the light emission from a tunnel junction in a low-temperature ultrahigh-vacuum (UHV) scanning tunneling microscope (STM). To achieve the BFP imaging in a UHV environment, a compact "all-in-one" sample holder is designed and fabricated, which allows us to integrate the sample substrate with the photon collection units that include a hemisphere solid immersion lens and an aspherical collecting lens. Such a specially designed holder enables the characterization of light emission both within and beyond the critical angle and also facilitates the optical alignment inside a UHV chamber. To test the performance of the BFP imaging system, we first measure the photoluminescence from dye-doped polystyrene beads on a thin Ag film. A double-ring pattern is observed in the BFP image, arising from two kinds of emission channels: strong surface plasmon coupled emissions around the surface plasmon resonance angle and weak transmitted fluorescence maximized at the critical angle, respectively. Such an observation also helps to determine the emission angle for each image pixel in the BFP image and, more importantly, proves the feasibility of our BFP imaging system. Furthermore, as a proof-of-principle experiment, electrically driven plasmon emissions are used to demonstrate the capability of the constructed BFP imaging system for STM induced electroluminescence measurements. A single-ring pattern is obtained in the BFP image, which reveals the generation and detection of the leakage radiation from the surface plasmon propagating on the Ag surface. Further analyses of the BFP image provide valuable information on the emission angle of the leakage radiation, the orientation of the radiating dipole, and the plasmon wavevector. The UHV-BFP imaging technique demonstrated here opens new routes for future studies on the angular distributed emission and dipole orientation of individual quantum emitters in UHV.
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Affiliation(s)
- Yun-Jie Yu
- Hefei National Research Center 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
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
| | - Yan Kuai
- Advanced Laser Technology Laboratory of Anhui Province, Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yong-Tao Fan
- Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Liang-Fu Zhu
- Advanced Laser Technology Laboratory of Anhui Province, Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Fan-Fang Kong
- Hefei National Research Center 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
| | - Xiao-Jun Tian
- Hefei National Research Center 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
| | - Shi-Hao Jing
- Hefei National Research Center 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
| | - Li Zhang
- Hefei National Research Center 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
| | - Dou-Guo Zhang
- Hefei National Research Center 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
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
- Advanced Laser Technology Laboratory of Anhui Province, Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yao Zhang
- Hefei National Research Center 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
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yang Zhang
- Hefei National Research Center 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
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhen-Chao Dong
- Hefei National Research Center 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
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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8
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Doležal J, Canola S, Hapala P, de Campos Ferreira RC, Merino P, Švec M. Evidence of exciton-libron coupling in chirally adsorbed single molecules. Nat Commun 2022; 13:6008. [PMID: 36224183 PMCID: PMC9556530 DOI: 10.1038/s41467-022-33653-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 09/28/2022] [Indexed: 11/18/2022] Open
Abstract
Interplay between motion of nuclei and excitations has an important role in molecular photophysics of natural and artificial structures. Here we provide a detailed analysis of coupling between quantized librational modes (librons) and charged excited states (trions) on single phthalocyanine dyes adsorbed on a surface. By means of tip-induced electroluminescence performed with a scanning probe microscope, we identify libronic signatures in spectra of chirally adsorbed phthalocyanines and find that these signatures are absent from spectra of symmetrically adsorbed species. We create a model of the libronic coupling based on the Franck-Condon principle to simulate the spectral features. Experimentally measured librational spectra match very well the theoretically calculated librational eigenenergies and peak intensities (Franck-Condon factors). Moreover, the comparison reveals an unexpected depopulation channel for the zero libron of the excited state that can be effectively controlled by tuning the size of the nanocavity. Our results showcase the possibility of characterizing the dynamics of molecules by their low-energy molecular modes using µeV-resolved tip-enhanced spectroscopy. Vibronic coupling in molecules plays an essential role in photophysics. Here, the authors observe optical fingerprints of the coupling between librational states and charged excited states in a single phthalocyanine molecule chirally absorbed on a surface.
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Affiliation(s)
- Jiří Doležal
- Institute of Physics, Czech Academy of Sciences, CZ16200, Praha 6, Czech Republic. .,Faculty of Mathematics and Physics, Charles University, CZ12116, Praha 2, Czech Republic.
| | - Sofia Canola
- Institute of Physics, Czech Academy of Sciences, CZ16200, Praha 6, Czech Republic
| | - Prokop Hapala
- Institute of Physics, Czech Academy of Sciences, CZ16200, Praha 6, Czech Republic
| | | | - Pablo Merino
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, E08193, Barcelona, Spain.,Instituto de Ciencia de Materiales de Madrid; CSIC, E28049, Madrid, Spain
| | - Martin Švec
- Institute of Physics, Czech Academy of Sciences, CZ16200, Praha 6, Czech Republic. .,Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, CZ16000, Praha 6, Czech Republic.
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9
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Imada H, Imai-Imada M, Ouyang X, Muranaka A, Kim Y. Anti-Kasha emissions of single molecules in a plasmonic nanocavity. J Chem Phys 2022; 157:104302. [DOI: 10.1063/5.0102087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Kasha's rule generally holds true for solid-state molecular systems, where the rates of internal conversion and vibrational relaxation are sufficiently higher than the luminescence rate. In contrast, in systems where plasmons and matter interact strongly, the luminescence rate is significantly enhanced, leading to the emergence of luminescence that does not obey Kasha's rule. In this work, we investigate the anti-Kasha emissions of single molecules, free-base and magnesium naphthalocyanine (H2Nc and MgNc), in a plasmonic nanocavity formed between the tip of a scanning tunneling microscope (STM) and metal substrate. A narrow-line tunable laser was employed to precisely reveal the excited-state levels of a single molecule located under the tip and to selectively excite it into a specific excited state, followed by obtaining STM-photoluminescence (STM-PL) spectrum to reveal energy relaxation from the state. The excitation to higher-lying states of H2Nc caused various changes in the emission spectrum, such as broadening and the appearance of new peaks, implying the breakdown of Kasha's rule. These observations indicate emissions from the vibrationally excited states in the first singlet excited state ( S1) and second singlet excited state ( S2), as well as internal conversion from S2 to S1. Moreover, we obtained direct evidence of electronic and vibronic transitions from the vibrationally excited states, from the STM-PL measurements of MgNc. The results obtained herein shed light on the energy dynamics of molecular systems under a plasmonic field and highlight the possibility of obtaining various energy-converting functions using anti-Kasha processes.
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10
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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.
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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
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11
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Yamamoto S, Imada H, Kim Y. Atomic-Scale Photon Mapping Revealing Spin-Current Relaxation. PHYSICAL REVIEW LETTERS 2022; 128:206804. [PMID: 35657881 DOI: 10.1103/physrevlett.128.206804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 04/19/2022] [Indexed: 06/15/2023]
Abstract
A nanoscopic understanding of spin-current dynamics is crucial for controlling the spin transport in materials. However, gaining access to spin-current dynamics at an atomic scale is challenging. Therefore, we developed spin-polarized scanning tunneling luminescence spectroscopy (SP STLS) to visualize the spin relaxation strength depending on spin injection positions. Atomically resolved SP STLS mapping of gallium arsenide demonstrated a stronger spin relaxation in gallium atomic rows. Hence, SP STLS paves the way for visualizing spin current with single-atom precision.
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Affiliation(s)
- Shunji Yamamoto
- Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Hiroshi Imada
- Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Yousoo Kim
- Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
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12
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Peña Román RJ, Auad Y, Grasso L, Padilha LA, Alvarez F, Barcelos ID, Kociak M, Zagonel LF. Design and implementation of a device based on an off-axis parabolic mirror to perform luminescence experiments in a scanning tunneling microscope. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:043704. [PMID: 35489916 DOI: 10.1063/5.0078423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 02/27/2022] [Indexed: 06/14/2023]
Abstract
We present the design, implementation, and illustrative results of a light collection/injection strategy based on an off-axis parabolic mirror collector for a low-temperature Scanning Tunneling Microscope (STM). This device allows us to perform STM induced Light Emission (STM-LE) and Cathodoluminescence (STM-CL) experiments and in situ Photoluminescence (PL) and Raman spectroscopy as complementary techniques. Considering the Étendue conservation and using an off-axis parabolic mirror, it is possible to design a light collection and injection system that displays 72% of collection efficiency (considering the hemisphere above the sample surface) while maintaining high spectral resolution and minimizing signal loss. The performance of the STM is tested by atomically resolved images and scanning tunneling spectroscopy results on standard sample surfaces. The capabilities of our system are demonstrated by performing STM-LE on metallic surfaces and two-dimensional semiconducting samples, observing both plasmonic and excitonic emissions. In addition, we carried out in situ PL measurements on semiconducting monolayers and quantum dots and in situ Raman on graphite and hexagonal boron nitride (h-BN) samples. Additionally, STM-CL and PL were obtained on monolayer h-BN gathering luminescence spectra that are typically associated with intragap states related to carbon defects. The results show that the flexible and efficient light injection and collection device based on an off-axis parabolic mirror is a powerful tool to study several types of nanostructures with multiple spectroscopic techniques in correlation with their morphology at the atomic scale and electronic structure.
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Affiliation(s)
- Ricardo Javier Peña Román
- "Gleb Wataghin" Institute of Physics, University of Campinas-UNICAMP, 13083-859 Campinas, SP, Brazil
| | - Yves Auad
- "Gleb Wataghin" Institute of Physics, University of Campinas-UNICAMP, 13083-859 Campinas, SP, Brazil
| | - Lucas Grasso
- "Gleb Wataghin" Institute of Physics, University of Campinas-UNICAMP, 13083-859 Campinas, SP, Brazil
| | - Lazaro A Padilha
- "Gleb Wataghin" Institute of Physics, University of Campinas-UNICAMP, 13083-859 Campinas, SP, Brazil
| | - Fernando Alvarez
- "Gleb Wataghin" Institute of Physics, University of Campinas-UNICAMP, 13083-859 Campinas, SP, Brazil
| | - Ingrid David Barcelos
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-970 Campinas, SP, Brazil
| | - Mathieu Kociak
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - Luiz Fernando Zagonel
- "Gleb Wataghin" Institute of Physics, University of Campinas-UNICAMP, 13083-859 Campinas, SP, Brazil
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13
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Rosławska A, Merino P, Grewal A, Leon CC, Kuhnke K, Kern K. Atomic-Scale Structural Fluctuations of a Plasmonic Cavity. NANO LETTERS 2021; 21:7221-7227. [PMID: 34428071 PMCID: PMC8887667 DOI: 10.1021/acs.nanolett.1c02207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Optical spectromicroscopies, which can reach atomic resolution due to plasmonic enhancement, are perturbed by spontaneous intensity modifications. Here, we study such fluctuations in plasmonic electroluminescence at the single-atom limit profiting from the precision of a low-temperature scanning tunneling microscope. First, we investigate the influence of a controlled single-atom transfer from the tip to the sample on the plasmonic properties of the junction. Next, we form a well-defined atomic contact of several quanta of conductance. In contact, we observe changes of the electroluminescence intensity that can be assigned to spontaneous modifications of electronic conductance, plasmonic excitation, and optical antenna properties all originating from minute atomic rearrangements at or near the contact. Our observations are relevant for the understanding of processes leading to spontaneous intensity variations in plasmon-enhanced atomic-scale spectroscopies such as intensity blinking in picocavities.
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Affiliation(s)
- Anna Rosławska
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
- Université
de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - Pablo Merino
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
- Instituto
de Ciencia de Materiales de Madrid, CSIC, E-28049 Madrid, Spain
- Instituto
de Física Fundamental, CSIC, E-28006 Madrid, Spain
| | - Abhishek Grewal
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
| | | | - Klaus Kuhnke
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
| | - Klaus Kern
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
- Institut
de Physique, École Polytechnique
Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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14
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Cao S, Rosławska A, Doppagne B, Romeo M, Féron M, Chérioux F, Bulou H, Scheurer F, Schull G. Energy funnelling within multichromophore architectures monitored with subnanometre resolution. Nat Chem 2021; 13:766-770. [PMID: 34031563 DOI: 10.1038/s41557-021-00697-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 04/08/2021] [Indexed: 02/04/2023]
Abstract
The funnelling of energy within multichromophoric assemblies is at the heart of the efficient conversion of solar energy by plants. The detailed mechanisms of this process are still actively debated as they rely on complex interactions between a large number of chromophores and their environment. Here we used luminescence induced by scanning tunnelling microscopy to probe model multichromophoric structures assembled on a surface. Mimicking strategies developed by photosynthetic systems, individual molecules were used as ancillary, passive or blocking elements to promote and direct resonant energy transfer between distant donor and acceptor units. As it relies on organic chromophores as the elementary components, this approach constitutes a powerful model to address fundamental physical processes at play in natural light-harvesting complexes.
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Affiliation(s)
- Shuiyan Cao
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, Strasbourg, France.,Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing, China
| | - Anna Rosławska
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, Strasbourg, France.
| | | | | | - Michel Féron
- Université Bourgogne Franche-Comté, FEMTO-ST, UFC, CNRS, Besançon, France
| | - Frédéric Chérioux
- Université Bourgogne Franche-Comté, FEMTO-ST, UFC, CNRS, Besançon, France
| | - Hervé Bulou
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, Strasbourg, France
| | - Fabrice Scheurer
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, Strasbourg, France
| | - Guillaume Schull
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, Strasbourg, France.
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15
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Imada H, Imai-Imada M, Miwa K, Yamane H, Iwasa T, Tanaka Y, Toriumi N, Kimura K, Yokoshi N, Muranaka A, Uchiyama M, Taketsugu T, Kato YK, Ishihara H, Kim Y. Single-molecule laser nanospectroscopy with micro-electron volt energy resolution. Science 2021; 373:95-98. [PMID: 34210883 DOI: 10.1126/science.abg8790] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 05/22/2021] [Indexed: 12/16/2022]
Abstract
Ways to characterize and control excited states at the single-molecule and atomic levels are needed to exploit excitation-triggered energy-conversion processes. Here, we present a single-molecule spectroscopic method with micro-electron volt energy and submolecular-spatial resolution using laser driving of nanocavity plasmons to induce molecular luminescence in scanning tunneling microscopy. This tunable and monochromatic nanoprobe allows state-selective characterization of the energy levels and linewidths of individual electronic and vibrational quantum states of a single molecule. Moreover, we demonstrate that the energy levels of the states can be finely tuned by using the Stark effect and plasmon-exciton coupling in the tunneling junction. Our technique and findings open a route to the creation of designed energy-converting functions by using tuned energy levels of molecular systems.
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Affiliation(s)
- Hiroshi Imada
- Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan. .,PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
| | - Miyabi Imai-Imada
- Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Kuniyuki Miwa
- Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.,Institute for Molecular Science, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Hidemasa Yamane
- Department of Physics and Electronics, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
| | - Takeshi Iwasa
- PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan.,Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan.,Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 060-0810, Japan
| | - Yusuke Tanaka
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.,Advanced Elements Chemistry Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Naoyuki Toriumi
- Advanced Elements Chemistry Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Kensuke Kimura
- Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Nobuhiko Yokoshi
- Department of Physics and Electronics, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
| | - Atsuya Muranaka
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.,Advanced Elements Chemistry Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Masanobu Uchiyama
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.,Advanced Elements Chemistry Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Tetsuya Taketsugu
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan.,Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 060-0810, Japan
| | - Yuichiro K Kato
- Nanoscale Quantum Photonics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.,Quantum Optoelectronics Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan
| | - Hajime Ishihara
- Department of Physics and Electronics, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.,Department of Materials Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan.,Center for Quantum Information and Quantum Biology, Osaka University 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Yousoo Kim
- Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.
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16
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Rosławska A, Merino P, Leon CC, Grewal A, Etzkorn M, Kuhnke K, Kern K. Gigahertz Frame Rate Imaging of Charge-Injection Dynamics in a Molecular Light Source. NANO LETTERS 2021; 21:4577-4583. [PMID: 34038142 PMCID: PMC8193635 DOI: 10.1021/acs.nanolett.1c00328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 04/22/2021] [Indexed: 06/12/2023]
Abstract
Light sources on the scale of single molecules can be addressed and characterized at their proper sub-nanometer scale by scanning tunneling microscopy-induced luminescence (STML). Such a source can be driven by defined short charge pulses while the luminescence is detected with sub-nanosecond resolution. We introduce an approach to concurrently image the molecular emitter, which is based on an individual defect, with its local environment along with its luminescence dynamics at a resolution of a billion frames per second. The observed dynamics can be assigned to the single electron capture occurring in the low-nanosecond regime. While the emitter's location on the surface remains fixed, the scanning of the tip modifies the energy landscape for charge injection into the defect. The principle of measurement is extendable to fundamental processes beyond charge transfer, like exciton diffusion.
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Affiliation(s)
- Anna Rosławska
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
- Université
de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - Pablo Merino
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
- Instituto
de Ciencia de Materiales de Madrid, CSIC, E-28049 Madrid, Spain
- Instituto
de Física Fundamental, CSIC, E-28006 Madrid, Spain
| | | | - Abhishek Grewal
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
| | - Markus Etzkorn
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
- Institut
für Angewandte Physik, TU Braunschweig, D-38106 Braunschweig, Germany
| | - Klaus Kuhnke
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
| | - Klaus Kern
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
- Institut
de Physique, École Polytechnique Fédérale de
Lausanne, CH-1015 Lausanne, Switzerland
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17
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Doležal J, Merino P, Švec M. Constant amplitude driving of a radiofrequency excited plasmonic tunnel junction. APPLIED PHYSICS LETTERS 2021; 118:193301. [PMID: 34257502 PMCID: PMC7611201 DOI: 10.1063/5.0048476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 04/17/2021] [Indexed: 06/13/2023]
Abstract
Constant-amplitude bias modulation over a broad range of microwave frequencies is a prerequisite for application in high-resolution spectroscopic techniques in a tunneling junction as e.g. electron spin resonance spectroscopy or optically detected paramagnetic resonance. Here, we present an optical method for determining the frequency-dependent magnitude of the transfer function of a dedicated high-frequency line integrated with a scanning probe microscope. The method relies on determining the energy cutoff of the plasmonic electroluminescence spectrum, which is linked to the energies of the electrons inelastically tunneling across the junction. We develop an easy-to-implement procedure for effective compensation of an RF line and determination of the transfer function magnitude in the GHz range. We test our method with conventional electronic calibration and find a perfect agreement.
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Affiliation(s)
- Jiří Doležal
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10/112, CZ16200 Praha 6, Czech Republic
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, CZ12116 Praha 2, Czech Republic
| | - Pablo Merino
- Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz 3, E28049 Madrid, Spain
- Instituto de Física Fundamental, CSIC, Serrano 121, E28006 Madrid, Spain
| | - Martin Švec
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10/112, CZ16200 Praha 6, Czech Republic
- Regional Centre of Advanced Technologies and Materials, CATRIN, Palacky University Olomouc, Šlechtitelů 27, CZ78371 Olomouc, Czech Republic
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18
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Doležal J, Canola S, Merino P, Švec M. Exciton-Trion Conversion Dynamics in a Single Molecule. ACS NANO 2021; 15:7694-7699. [PMID: 33793192 PMCID: PMC7611190 DOI: 10.1021/acsnano.1c01318] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Charged optical excitations (trions) generated by charge carrier injection are crucial for emerging optoelectronic technologies as they can be produced and manipulated by electric fields. Trions and neutral excitons can be efficiently induced in single molecules by means of tip-enhanced spectromicroscopic techniques. However, little is known of the exciton-trion dynamics at single molecule level as this requires methods permitting simultaneous subnanometer and subnanosecond characterization. Here, we investigate exciton-trion dynamics by phase fluorometry, combining radio frequency modulated scanning tunnelling luminescence with time-resolved single photon detection. We generate excitons and trions in single Zinc Phthalocyanine (ZnPc) molecules on NaCl/Ag(111), and trace the evolution of the system in the picosecond range. We explore the dependence of effective lifetimes on bias voltage and describe the conversion mechanism from neutral excitons to trions, via charge capture, as the primary pathway to trion formation. We corroborate the dynamics of the system by a causally deterministic four-state model.
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Affiliation(s)
- Jiří Doležal
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10/112, CZ16200 Praha 6, Czech Republic
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, CZ12116 Praha 2, Czech Republic
| | - Sofia Canola
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10/112, CZ16200 Praha 6, Czech Republic
| | - Pablo Merino
- Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz 3, E28049 Madrid, Spain
- Instituto de Física Fundamental, CSIC, Serrano 121, E28006 Madrid, Spain
| | - Martin Švec
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10/112, CZ16200 Praha 6, Czech Republic
- Regional Centre of Advanced Technologies and Materials, Šlechtitelů 27, CZ78371 Olomouc, Czech Republic
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19
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Aguilar-Galindo F, Borisov AG, Díaz-Tendero S. Ultrafast Dynamics of Electronic Resonances in Molecules Adsorbed on Metal Surfaces: A Wave Packet Propagation Approach. J Chem Theory Comput 2021; 17:639-654. [PMID: 33508201 DOI: 10.1021/acs.jctc.0c01031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present a wave packet propagation-based method to study the electron dynamics in molecular species in the gas phase and adsorbed on metal surfaces. It is a very general method that can be employed to any system where the electron dynamics is dominated by an active electron and the coupling between the discrete and continuum electronic states is of importance. As an example, one can consider resonant molecule-surface electron transfer or molecular photoionization. Our approach is based on a computational strategy allowing incorporating ab initio inputs from quantum chemistry methods, such as density functional theory, Hartree-Fock, and coupled cluster. Thus, the electronic structure of the molecule is fully taken into account. The electron wave function is represented on a three-dimensional grid in spatial coordinates, and its temporal evolution is obtained from the solution of the time-dependent Schrödinger equation. We illustrate our method with an example of the electron dynamics of anionic states localized on organic molecules adsorbed on metal surfaces. In particular, we study resonant charge transfer from the π* orbitals of three vinyl derivatives (acrylamide, acrylonitrile, and acrolein) adsorbed on a Cu(100) surface. Electron transfer between these lowest unoccupied molecular orbitals and the metal surface is extremely fast, leading to a decay of the population of the molecular anion on the femtosecond timescale. We detail how to analyze the time-dependent electronic wave function in order to obtain the relevant information on the system: the energies and lifetimes of the molecule-localized quasistationary states, their resonant wavefunctions, and the population decay channels. In particular, we demonstrate the effect of the electronic structure of the substrate on the energy and momentum distribution of the hot electrons injected into the metal by the decaying molecular resonance.
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Affiliation(s)
- Fernando Aguilar-Galindo
- Departmento de Química, Módulo 13, Universidad Autónoma de Madrid, Madrid 28049, Spain.,Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastián E-20018, Spain
| | - Andrey G Borisov
- Institut des Sciences Moléculaires d'Orsay, UMR 8214, CNRS, Université Paris-Saclay, Orsay 91405, France
| | - Sergio Díaz-Tendero
- Departmento de Química, Módulo 13, Universidad Autónoma de Madrid, Madrid 28049, Spain.,Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid 28049, Spain.,Institute for Advanced Research in Chemical Science (IAdChem), Universidad Autónoma de Madrid, Madrid 28049, Spain
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20
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Farrukh A, Tian XJ, Kong FF, Yu YJ, Jing SH, Chen G, Zhang Y, Liao Y, Zhang Y, Dong ZC. Bias-polarity dependent electroluminescence from a single platinum phthalocyanine molecule. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2007114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Aftab Farrukh
- 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 230026, China
| | - Xiao-jun 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 230026, China
| | - Fan-fang 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 230026, China
| | - Yun-jie 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 230026, China
| | - Shi-hao Jing
- 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 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 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 230026, China
| | - Yuan Liao
- 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 230026, 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 230026, China
| | - Zhen-chao 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 230026, China
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21
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Luo Y, Kong FF, Tian XJ, Yu YJ, Zhang L, Chen G, Zhang Y, Zhang Y, Dong ZC. What can single-molecule Fano resonance tell? J Chem Phys 2021; 154:044309. [PMID: 33514086 DOI: 10.1063/5.0033200] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
In this work, we showcase applications of single-molecule Fano resonance (SMFR) measurements beyond the determination of molecular excitonic energy and associated dipole orientation. We use the SMFR measurement to probe the local influence of a man-made single chlorine vacancy on the molecular transition of a single zinc phthalocyanine, which clearly reveals the lifting-up of the double degeneracy of the excited states due to defect-induced configurational changes. Furthermore, time-trace SMFR measurements at different excitation voltages are used to track the tautomerization process in a free-base phthalocyanine. Different behaviors in switching between two inner-hydrogen configurations are observed with decreasing voltages, which helps to reveal the underlying tautomerization mechanism involving both the molecular electronic excited states and vibrational excited states in the ground state.
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Affiliation(s)
- Yang Luo
- 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
| | - Fan-Fang Kong
- 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
| | - Xiao-Jun Tian
- 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
| | - Yun-Jie Yu
- 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
| | - Li Zhang
- 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
| | - Gong Chen
- 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
| | - Yao Zhang
- 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
| | - Yang Zhang
- 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
| | - Zhen-Chao Dong
- 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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22
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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: 18] [Impact Index Per Article: 4.5] [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.
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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
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23
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Schultz JF, Li S, Jiang S, Jiang N. Optical scanning tunneling microscopy based chemical imaging and spectroscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:463001. [PMID: 32702674 DOI: 10.1088/1361-648x/aba8c7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 07/23/2020] [Indexed: 06/11/2023]
Abstract
Through coupling optical processes with the scanning tunneling microscope (STM), single-molecule chemistry and physics have been investigated at the ultimate spatial and temporal limit. Electrons and photons can be used to drive interactions and reactions in chemical systems and simultaneously probe their characteristics and consequences. In this review we introduce and review methods to couple optical imaging and spectroscopy with scanning tunneling microscopy. The integration of the STM and optical spectroscopy provides new insights into individual molecular adsorbates, surface-supported molecular assemblies, and two-dimensional materials with subnanoscale resolution, enabling the fundamental study of chemistry at the spatial and temporal limit. The inelastic scattering of photons by molecules and materials, that results in unique and sensitive vibrational fingerprints, will be considered with tip-enhanced Raman spectroscopy. STM-induced luminescence examines the intrinsic luminescence of organic adsorbates and their energy transfer and charge transfer processes with their surroundings. We also provide a survey of recent efforts to probe the dynamics of optical excitation at the molecular level with scanning tunneling microscopy in the context of light-induced photophysical and photochemical transformations.
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Affiliation(s)
- Jeremy F Schultz
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, United States of America
| | - Shaowei Li
- Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093, United States of America
- Kavli Energy NanoScience Institute, University of California, Berkeley, CA 94720, United States of America
| | - Song Jiang
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - Nan Jiang
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, United States of America
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24
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Doležal J, Mutombo P, Nachtigallová D, Jelínek P, Merino P, Švec M. Mechano-Optical Switching of a Single Molecule with Doublet Emission. ACS NANO 2020; 14:8931-8938. [PMID: 32539338 PMCID: PMC7116298 DOI: 10.1021/acsnano.0c03730] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The ability to control the emission from single-molecule quantum emitters is an important step toward their implementation in optoelectronic technology. Phthalocyanine and derived metal complexes on thin insulating layers studied by scanning tunneling microscope-induced luminescence (STML) offer an excellent playground for tuning their excitonic and electronic states by Coulomb interaction and to showcase their high environmental sensitivity. Copper phthalocyanine (CuPc) has an open-shell electronic structure, and its lowest-energy exciton is a doublet, which brings interesting prospects in its application for optospintronic devices. Here, we demonstrate that the excitonic state of a single CuPc molecule can be reproducibly switched by atomic-scale manipulations permitting precise positioning of the molecule on the NaCl ionic crystal lattice. Using a combination of STML, AFM, and ab initio calculations, we show the modulation of electronic and optical bandgaps and the exciton binding energy in CuPc by tens of meV. We explain this effect by spatially dependent Coulomb interaction occurring at the molecule-insulator interface, which tunes the local dielectric environment of the emitter.
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Affiliation(s)
- Jiří Doležal
- Institute of Physics, Czech Academy of Sciences, Praha, Czech Republic
- Faculty of Mathematics and Physics, Charles University, Praha, Czech Republic
| | - Pingo Mutombo
- Institute of Physics, Czech Academy of Sciences, Praha, Czech Republic
- Department of Petrochemistry and Refining, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Dana Nachtigallová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Praha, Czech Republic
- Regional Centre of Advanced Technologies and Materials, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Pavel Jelínek
- Institute of Physics, Czech Academy of Sciences, Praha, Czech Republic
- Regional Centre of Advanced Technologies and Materials, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Pablo Merino
- Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz 3, E28049, Madrid, Spain
- Instituto de Física Fundamental, CSIC, Serrano 121, E28006, Madrid, Spain
| | - Martin Švec
- Institute of Physics, Czech Academy of Sciences, Praha, Czech Republic
- Regional Centre of Advanced Technologies and Materials, Šlechtitelů 27, 78371 Olomouc, Czech Republic
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25
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Rosławska A, Leon CC, Grewal A, Merino P, Kuhnke K, Kern K. Atomic-Scale Dynamics Probed by Photon Correlations. ACS NANO 2020; 14:6366-6375. [PMID: 32479059 PMCID: PMC7315641 DOI: 10.1021/acsnano.0c03704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Light absorption and emission have their origins in fast atomic-scale phenomena. To characterize these basic steps (e.g., in photosynthesis, luminescence, and quantum optics), it is necessary to access picosecond temporal and picometer spatial scales simultaneously. In this Perspective, we describe how state-of-the-art picosecond photon correlation spectroscopy combined with luminescence induced at the atomic scale with a scanning tunneling microscope (STM) enables such studies. We outline recent STM-induced luminescence work on single-photon emitters and the dynamics of excitons, charges, molecules, and atoms as well as several prospective experiments concerning light-matter interactions at the nanoscale. We also describe future strategies for measuring and rationalizing ultrafast phenomena at the nanoscale.
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Affiliation(s)
- Anna Rosławska
- Max-Planck-Institut
für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Christopher C. Leon
- Max-Planck-Institut
für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Abhishek Grewal
- Max-Planck-Institut
für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Pablo Merino
- Max-Planck-Institut
für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
- Instituto
de Ciencia de Materiales de Madrid, CSIC, c/Sor Juana Inés de la Cruz 3, E28049 Madrid, Spain
- Instituto
de Física Fundamental, CSIC, Serrano 121, E28006 Madrid, Spain
| | - 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
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26
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Leon CC, Gunnarsson O, de Oteyza DG, Rosławska A, Merino P, Grewal A, Kuhnke K, Kern K. Single Photon Emission from a Plasmonic Light Source Driven by a Local Field-Induced Coulomb Blockade. ACS NANO 2020; 14:4216-4223. [PMID: 32159937 PMCID: PMC7199210 DOI: 10.1021/acsnano.9b09299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 03/11/2020] [Indexed: 05/24/2023]
Abstract
A hallmark of quantum control is the ability to manipulate quantum emission at the nanoscale. Through scanning tunneling microscopy-induced luminescence (STML), we are able to generate plasmonic light originating from inelastic tunneling processes that occur in the vacuum between a tip and a few-nanometer-thick molecular film of C60 deposited on Ag(111). Single photon emission, not of molecular excitonic origin, occurs with a 1/e recovery time of a tenth of a nanosecond or less, as shown through Hanbury Brown and Twiss photon intensity interferometry. Tight-binding calculations of the electronic structure for the combined tip and Ag-C60 system results in good agreement with experiment. The tunneling happens through electric-field-induced split-off states below the C60 LUMO band, which leads to a Coulomb blockade effect and single photon emission. The use of split-off states is shown to be a general technique that has special relevance for narrowband materials with a large bandgap.
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Affiliation(s)
| | - Olle Gunnarsson
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
| | - Dimas G. de Oteyza
- Donostia
International Physics Center, E-20018 San Sebastián, Spain
- Centro
de Fisica de Materiales, CSIC-UPV/EHU, E-20018 San Sebastián, Spain
- Ikerbasque,
Basque Foundation for Science, E-48013 Bilbao, Spain
| | - Anna Rosławska
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
| | - Pablo Merino
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
- Instituto
de Ciencia de Materiales de Madrid, CSIC, c/Sor Juana Inés de la Cruz 3, E-28049 Madrid, Spain
- Instituto
de Física Fundamental, CSIC, Serrano 121, E-28006, Madrid, Spain
| | - Abhishek Grewal
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
| | - Klaus Kuhnke
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
| | - Klaus Kern
- Max-Planck-Institut
für Festkörperforschung, D-70569 Stuttgart, Germany
- Institut
de Physique, École Polytechnique Fédérale de
Lausanne, CH-1015 Lausanne, Switzerland
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27
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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: 24] [Impact Index Per Article: 6.0] [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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28
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Schaeverbeke Q, Avriller R, Frederiksen T, Pistolesi F. Single-Photon Emission Mediated by Single-Electron Tunneling in Plasmonic Nanojunctions. PHYSICAL REVIEW LETTERS 2019; 123:246601. [PMID: 31922843 DOI: 10.1103/physrevlett.123.246601] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Indexed: 05/24/2023]
Abstract
Recent scanning tunneling microscopy (STM) experiments reported single-molecule fluorescence induced by tunneling currents in the nanoplasmonic cavity formed by the STM tip and the substrate. The electric field of the cavity mode couples with the current-induced charge fluctuations of the molecule, allowing the excitation of photons. We investigate theoretically this system for the experimentally relevant limit of large damping rate κ for the cavity mode and arbitrary coupling strength to a single-electronic level. We find that for bias voltages close to the first inelastic threshold of photon emission, the emitted light displays antibunching behavior with vanishing second-order photon correlation function. At the same time, the current and the intensity of emitted light display Franck-Condon steps at multiples of the cavity frequency ω_{c} with a width controlled by κ rather than the temperature T. For large bias voltages, we predict strong photon bunching of the order of κ/Γ where Γ is the electronic tunneling rate. Our theory thus predicts that strong coupling to a single level allows current-driven nonclassical light emission.
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Affiliation(s)
- Q Schaeverbeke
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
- Donostia International Physics Center (DIPC), E-20018 Donostia-San Sebastián, Spain
| | - R Avriller
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
| | - T Frederiksen
- Donostia International Physics Center (DIPC), E-20018 Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, E-48013 Bilbao, Spain
| | - F Pistolesi
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
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29
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Doležal J, Merino P, Redondo J, Ondič L, Cahlík A, Švec M. Charge Carrier Injection Electroluminescence with CO-Functionalized Tips on Single Molecular Emitters. NANO LETTERS 2019; 19:8605-8611. [PMID: 31738569 PMCID: PMC7116301 DOI: 10.1021/acs.nanolett.9b03180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We investigate electroluminescence of single molecular emitters on NaCl on Ag(111) and Au(111) with submolecular resolution in a low-temperature scanning probe microscope with tunneling current, atomic force, and light detection capabilities. The role of the tip state is studied in the photon maps of a prototypical emitter, zinc phthalocyanine (ZnPc), using metal and CO-metal tips. CO-functionalization is found to have an impact on the resolution and contrast of the photon maps due to the localized overlap of the p-orbitals on the tip with the molecular orbitals of the emitter. The possibility of using the same CO-functionalized tip for tip-enhanced photon detection and high resolution atomic force is demonstrated. We study the electroluminescence of ZnPc, induced by charge carrier injection at sufficiently high bias voltages. We propose that the distinct level alignment of the ZnPc frontier orbitals with the Au(111) and Ag(111) Fermi levels governs the primary excitation mechanisms as the injection of electrons and holes from the tip into the molecule, respectively. These findings put forward the importance of the tip status in the photon maps and contribute to a better understanding of the photophysics of organic molecules on surfaces.
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Affiliation(s)
- Jiří Doležal
- Institute of Physics, Czech Academy of Sciences, Praha, Czech Republic
| | - Pablo Merino
- Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz 3, E28049, Madrid, Spain
- Instituto de Física Fundamental, CSIC, Serrano 121, E28006, Madrid, Spain
| | - Jesus Redondo
- Institute of Physics, Czech Academy of Sciences, Praha, Czech Republic
| | - Lukáš Ondič
- Institute of Physics, Czech Academy of Sciences, Praha, Czech Republic
| | - Aleš Cahlík
- Institute of Physics, Czech Academy of Sciences, Praha, Czech Republic
- Regional Center for Advanced Materials and Technologies, Olomouc, Czech Republic
| | - Martin Švec
- Institute of Physics, Czech Academy of Sciences, Praha, Czech Republic
- Regional Center for Advanced Materials and Technologies, Olomouc, Czech Republic
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30
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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.
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31
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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: 36] [Impact Index Per Article: 7.2] [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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32
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Selective triplet exciton formation in a single molecule. Nature 2019; 570:210-213. [DOI: 10.1038/s41586-019-1284-2] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 04/02/2019] [Indexed: 11/08/2022]
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33
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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: 16] [Impact Index Per Article: 3.2] [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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34
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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: 14] [Impact Index Per Article: 2.8] [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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Leon CC, Rosławska A, Grewal A, Gunnarsson O, Kuhnke K, Kern K. Photon superbunching from a generic tunnel junction. SCIENCE ADVANCES 2019; 5:eaav4986. [PMID: 31093525 PMCID: PMC6510551 DOI: 10.1126/sciadv.aav4986] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 03/26/2019] [Indexed: 05/21/2023]
Abstract
Generating time-correlated photon pairs at the nanoscale is a prerequisite to creating highly integrated optoelectronic circuits that perform quantum computing tasks based on heralded single photons. Here, we demonstrate fulfilling this requirement with a generic tip-surface metal junction. When the junction is luminescing under DC bias, inelastic tunneling events of single electrons produce a stream of visible photons of plasmonic origin whose superbunching index is 17 (improved to a record of 70 by the authors during publication) when measured with a 53-ps instrumental resolution limit. The effect is driven electrically, rather than optically. This discovery has immediate and profound implications for quantum optics and cryptography, notwithstanding its fundamental importance to basic science and its ushering in of heralded photon experiments on the nanometer scale.
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Affiliation(s)
- Christopher C. Leon
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, DE-70569 Stuttgart, Germany
- Corresponding author. (C.C.L.); (K.Ku.)
| | - Anna Rosławska
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, DE-70569 Stuttgart, Germany
| | - Abhishek Grewal
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, DE-70569 Stuttgart, Germany
| | - Olle Gunnarsson
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, DE-70569 Stuttgart, Germany
| | - Klaus Kuhnke
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, DE-70569 Stuttgart, Germany
- Corresponding author. (C.C.L.); (K.Ku.)
| | - Klaus Kern
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, DE-70569 Stuttgart, Germany
- Institut de Physique, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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36
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Döring RC, Rosemann NW, Huttner A, Breuer T, Witte G, Chatterjee S. Charge-transfer processes and carrier dynamics at the pentacene-C 60 interface. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:134001. [PMID: 30645985 DOI: 10.1088/1361-648x/aafea7] [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
Heterostructures of pentacene (PEN) and buckminsterfullerene (C60) are frequently attracting scientific interest as a well-defined small-molecule model system for the study of internal interfaces between two organic semiconductors. They are prototypical representatives forming a donor-acceptor combination for studies of fundamental optoelectronic processes in organic photovoltaics. Despite their importance in exciton dissociation, the energetics of their interfacial charge-transfer (CT) states and their microscopic excitation dynamics are not yet clarified and still being discussed. Here, we present steady-state and time-resolved photoluminescence measurements on stacked heterostructures composed of these two materials. All experiments are performed in the visible and near-infrared spectral regions as CT states are expected at energies below the fundamental electronic transitions of the respective bulk materials. A characteristic, interface-specific emission at around 1.13-1.17 eV is found, which we attribute to an interfacial CT state. Its excitation energy dependence reveals the intricate relaxation dynamics of excitons formed in both constituent materials. Moreover, the analysis of the dynamics of the C60 excitons shows that the lifetime of this state is reduced in the presence of an interface with PEN. This quenching is attributed to a long-range interaction, i.e. the relaxation of excitations into the interfacial CT state.
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Affiliation(s)
- Robin C Döring
- Institute of Experimental Physics I, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
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37
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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.
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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
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38
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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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39
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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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40
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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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41
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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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42
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Zhang L, Yu YJ, Chen LG, Luo Y, Yang B, Kong FF, Chen G, Zhang Y, Zhang Q, Luo Y, Yang JL, Dong ZC, Hou JG. Electrically driven single-photon emission from an isolated single molecule. Nat Commun 2017; 8:580. [PMID: 28924226 PMCID: PMC5603600 DOI: 10.1038/s41467-017-00681-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 07/20/2017] [Indexed: 11/09/2022] Open
Abstract
Electrically driven molecular light emitters are considered to be one of the promising candidates as single-photon sources. However, it is yet to be demonstrated that electrically driven single-photon emission can indeed be generated from an isolated single molecule notwithstanding fluorescence quenching and technical challenges. Here, we report such electrically driven single-photon emission from a well-defined single molecule located inside a precisely controlled nanocavity in a scanning tunneling microscope. The effective quenching suppression and nanocavity plasmonic enhancement allow us to achieve intense and stable single-molecule electroluminescence. Second-order photon correlation measurements reveal an evident photon antibunching dip with the single-photon purity down to g(2)(0) = 0.09, unambiguously confirming the single-photon emission nature of the single-molecule electroluminescence. Furthermore, we demonstrate an ultrahigh-density array of identical single-photon emitters. Molecular emitters offer a promising solution for single-photon generation. Here, by exploiting electronic decoupling by an ultrathin dielectric spacer and emission enhancement by a resonant plasmonic nanocavity, the authors demonstrate electrically driven single-photon emission from a single molecule.
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Affiliation(s)
- 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
| | - Yun-Jie 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
| | - Liu-Guo 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
| | - 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
| | - Ben 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
| | - Fan-Fang 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
| | - 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
| | - 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.
| | - Qiang 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
| | - 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
| | - Jin-Long 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
| | - Zhen-Chao 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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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: 62] [Impact Index Per Article: 8.9] [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.
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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
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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
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45
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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.
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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
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46
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Cocker TL, Peller D, Yu P, Repp J, Huber R. Tracking the ultrafast motion of a single molecule by femtosecond orbital imaging. Nature 2016; 539:263-267. [PMID: 27830788 PMCID: PMC5597038 DOI: 10.1038/nature19816] [Citation(s) in RCA: 289] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 08/26/2016] [Indexed: 12/24/2022]
Abstract
Watching a single molecule move on its intrinsic time scale—one of the central goals of modern nanoscience—calls for measurements that combine ultrafast temporal resolution1–8 with atomic spatial resolution9–30. Steady-state experiments achieve the requisite spatial resolution, as illustrated by direct imaging of individual molecular orbitals using scanning tunnelling microscopy9–11 or the acquisition of tip-enhanced Raman and luminescence spectra with sub-molecular resolution27–29. But tracking the dynamics of a single molecule directly in the time domain faces the challenge that single-molecule excitations need to be confined to an ultrashort time window. A first step towards overcoming this challenge has combined scanning tunnelling microscopy with so-called ‘lightwave electronics”1–8, which uses the oscillating carrier wave of tailored light pulses to directly manipulate electronic motion on time scales faster even than that of a single cycle of light. Here we use such ultrafast terahertz scanning tunnelling microscopy to access a state-selective tunnelling regime, where the peak of a terahertz electric-field waveform transiently opens an otherwise forbidden tunnelling channel through a single molecular state and thereby removes a single electron from an individual pentacene molecule’s highest occupied molecular orbital within a time window shorter than one oscillation cycle of the terahertz wave. We exploit this effect to record ~100 fs snapshot images of the structure of the orbital involved, and to reveal through pump-probe measurements coherent molecular vibrations at terahertz frequencies directly in the time domain and with sub-angstrom spatial resolution. We anticipate that the combination of lightwave electronics1–8 and atomic resolution of our approach will open the door to controlling electronic motion inside individual molecules at optical clock rates.
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Affiliation(s)
- Tyler L Cocker
- Department of Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Dominik Peller
- Department of Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Ping Yu
- Department of Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Jascha Repp
- Department of Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Rupert Huber
- Department of Physics, University of Regensburg, 93040 Regensburg, Germany
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47
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Real-space investigation of energy transfer in heterogeneous molecular dimers. Nature 2016; 538:364-367. [DOI: 10.1038/nature19765] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/11/2016] [Indexed: 02/03/2023]
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Schull G. Physical chemistry: A close-up view of coupled molecules. Nature 2016; 531:587-8. [PMID: 27029273 DOI: 10.1038/531587a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Guillaume Schull
- Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 (CNRS-Université de Strasbourg), 67034 Strasbourg, France
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49
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Zhang Y, Luo Y, Zhang Y, Yu YJ, Kuang YM, Zhang L, Meng QS, Luo Y, Yang JL, Dong ZC, Hou JG. Visualizing coherent intermolecular dipole–dipole coupling in real space. Nature 2016; 531:623-7. [DOI: 10.1038/nature17428] [Citation(s) in RCA: 223] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 02/11/2016] [Indexed: 12/29/2022]
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50
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Große C, Gunnarsson O, Merino P, Kuhnke K, Kern K. Nanoscale Imaging of Charge Carrier and Exciton Trapping at Structural Defects in Organic Semiconductors. NANO LETTERS 2016; 16:2084-2089. [PMID: 26871739 DOI: 10.1021/acs.nanolett.6b00190] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Charge carrier and exciton trapping in organic semiconductors crucially determine the performance of organic (opto-)electronic devices such as organic field-effect transistors, light-emitting diodes, or solar cells. However, the microscopic origin of the relevant traps generally remains unclear, as most spectroscopic techniques are unable to simultaneously probe the electronic and morphological structure of individual traps. Here, we employ low-temperature scanning tunneling microscopy (STM) and spectroscopy (STS) as well as tight-binding calculations derived from ab initio calculations to image the localized electronic states arising at structural defects in thin C60 films (<10 ML). The spatially and spectrally resolved STM-induced luminescence at these states reveals an enhanced radiative decay of excitons, which is interpreted in terms of the local symmetry lowering and the trapping of excitons by an X-trap. The combined mapping of the STM-induced luminescence, electronic structure, and morphology thus provides new insights into the origin and characteristics of individual exciton traps in organic semiconductors and offers new avenues to study charge carrier and exciton dynamics on molecular scales.
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Affiliation(s)
- Christoph Große
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Olle Gunnarsson
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Pablo Merino
- 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
- École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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