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Luo Y, Martin-Jimenez A, Pisarra M, Martin F, Garg M, Kern K. Imaging and controlling coherent phonon wave packets in single graphene nanoribbons. Nat Commun 2023; 14:3484. [PMID: 37311753 DOI: 10.1038/s41467-023-39239-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 06/06/2023] [Indexed: 06/15/2023] Open
Abstract
The motion of atoms is at the heart of any chemical or structural transformation in molecules and materials. Upon activation of this motion by an external source, several (usually many) vibrational modes can be coherently coupled, thus facilitating the chemical or structural phase transformation. These coherent dynamics occur on the ultrafast timescale, as revealed, e.g., by nonlocal ultrafast vibrational spectroscopic measurements in bulk molecular ensembles and solids. Tracking and controlling vibrational coherences locally at the atomic and molecular scales is, however, much more challenging and in fact has remained elusive so far. Here, we demonstrate that the vibrational coherences induced by broadband laser pulses on a single graphene nanoribbon (GNR) can be probed by femtosecond coherent anti-Stokes Raman spectroscopy (CARS) when performed in a scanning tunnelling microscope (STM). In addition to determining dephasing (~440 fs) and population decay times (~1.8 ps) of the generated phonon wave packets, we are able to track and control the corresponding quantum coherences, which we show to evolve on time scales as short as ~70 fs. We demonstrate that a two-dimensional frequency correlation spectrum unequivocally reveals the quantum couplings between different phonon modes in the GNR.
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Affiliation(s)
- Yang Luo
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Alberto Martin-Jimenez
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Michele Pisarra
- INFN-LNF, Gruppo Collegato di Cosenza, Via P. Bucci, cubo 31C, 87036, Rende (CS), Italy
| | - Fernando Martin
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nano), Faraday 9, Cantoblanco, 28049, Madrid, Spain
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049, Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Manish Garg
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany.
| | - Klaus Kern
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
- Institut de Physique, Ecole Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
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2
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Yin R, Wang J, Qiu ZL, Meng J, Xu H, Wang Z, Liang Y, Zhao XJ, Ma C, Tan YZ, Li Q, Wang B. Step-Assisted On-Surface Synthesis of Graphene Nanoribbons Embedded with Periodic Divacancies. J Am Chem Soc 2022; 144:14798-14808. [PMID: 35926228 DOI: 10.1021/jacs.2c05570] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The bottom-up approach through on-surface synthesis of porous graphene nanoribbons (GNRs) presents a controllable manner for implanting periodic nanostructures to tune the electronic properties of GNRs in addition to bandgap engineering by width and edge configurations. However, owing to the existing steric hindrance in small pores like divacancies, it is still difficult to embed periodic divacancies with a nonplanar configuration into GNRs. Here, we demonstrate the on-surface synthesis of atomically precise eight-carbon-wide armchair GNRs embedded with periodic divacancies (DV8-aGNRs) by utilizing the monatomic step edges on the Au(111) surface. From a single molecular precursor correspondingly following a trans- and cis-coupling, the DV8-aGNR and another porous nanographene are respectively formed at step edges and on terraces at 720 and 570 K. Combining scanning tunneling microscopy/spectroscopy, atomic force microscopy, and first-principles calculations, we determine the out-of-plane conformation, wide bandgap (∼3.36 eV), and wiggly shaped frontier orbitals of the DV8-aGNR. Nudged elastic band calculations further quantitatively reveal that the additional steric hindrance effect in the cyclodehydrogenative reactions has a higher barrier of 1.3 eV than that in the planar porous nanographene, which also unveils the important role played by the monatomic Au step and adatoms in reducing the energy barriers and enhancing the thermodynamic preference of the oxidative cyclodehydrogenation. Our results provide the first case of GNRs containing periodic pores as small as divacancies with a nonplanar configuration and demonstrate the strategy by utilizing the chemical heterogeneity of a substrate to promote the formation of novel carbon nanomaterials.
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Affiliation(s)
- Ruoting Yin
- Hefei National Research Center 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
| | - Jianing Wang
- Hefei National Research Center 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-Lin Qiu
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory for Physical Chemistry of Solid Surfaces, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, 361005 Xiamen, China
| | - Jie Meng
- Hefei National Research Center 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
| | - Huimin Xu
- Hefei National Research Center 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
| | - Zhengya Wang
- Hefei National Research Center 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
| | - Yifan Liang
- Hefei National Research Center 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
| | - Xin-Jing Zhao
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory for Physical Chemistry of Solid Surfaces, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, 361005 Xiamen, China
| | - Chuanxu Ma
- Hefei National Research Center 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.,Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Yuan-Zhi Tan
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory for Physical Chemistry of Solid Surfaces, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, 361005 Xiamen, China
| | - Qunxiang Li
- Hefei National Research Center 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.,Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Bing Wang
- Hefei National Research Center 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.,Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
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3
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Bahrami M, Vasilopoulos P. Inhomogeneous linear responses and transport in armchair graphene nanoribbons in the presence of elastic scattering. NANOTECHNOLOGY 2022; 33:195201. [PMID: 35090140 DOI: 10.1088/1361-6528/ac4fe2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
Within linear-response theory we derive a response function that thoroughly accounts for the influence of elastic scattering and is valid beyond the long-wavelength limit. We use the theory to evaluate the polarization function and the conductivity in metallic armchair graphene nanoribbons in the Lindhard approximation for intra-band and inter-band transitions and for a relaxation timeτthat is not constant. We obtain a logarithmic behaviour in the scattering-independent polarization function not only for intra-band transitions, as is usually the case for one-dimensional systems, but also for inter-band transitions. Modifying the screening wave vector and the impurity density in the long-wavelength limit strongly influences the relaxation time. In contrast, for large wave vectors, this modification leads to a conservative value ofτ. We show that the imaginary part of the impurity-dependent conductivity varies with the wave vector while its scattering-independent part exists only for a single value of the wave vector.
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Affiliation(s)
- Mousa Bahrami
- Bita Quantum AI Inc., 2021 Av. Atwater, Montréal, Québec, H3H 2P2, Canada
| | - Panagiotis Vasilopoulos
- Department of Physics, Concordia University, 7141 Sherbrooke Ouest, Montréal, Québec, H4B 1R6, Canada
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Drummer MC, Singh V, Gupta N, Gesiorski JL, Weerasooriya RB, Glusac KD. Photophysics of nanographenes: from polycyclic aromatic hydrocarbons to graphene nanoribbons. PHOTOSYNTHESIS RESEARCH 2022; 151:163-184. [PMID: 33963981 DOI: 10.1007/s11120-021-00838-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/22/2021] [Indexed: 06/12/2023]
Abstract
Graphene quantum dots (GQDs) and nanoribbons (GNRs) are classes of nanographene molecules that exhibit highly tunable photophysical properties. There have been great strides in recent years to advance our understanding of nanographene photophysics and develop their use in light-harvesting systems, such as artificial photosynthesis. Here, we review the latest studies of GQDs and GNRs which have shed new light onto their photophysical underpinnings through computational and advanced spectroscopic techniques. We discuss how the size, symmetry, and shape of nanographenes influence their molecular orbital structures and, consequentially, their spectroscopic signatures. The scope of this review is to comprehensively lay out the general photophysics of nanographenes starting with benzene and building up to larger polycyclic aromatic hydrocarbons, GQDs, and GNRs. We also explore a collection of publications from recent years that build upon the current understanding of nanographene photophysics and their potential application in light-driven processes from display, lasing, and sensing technology to photocatalytic water splitting.
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Affiliation(s)
- Matthew C Drummer
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, IL, 60607, USA
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 Cass Avenue, Lemont, IL, 60439, USA
| | - Varun Singh
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, IL, 60607, USA
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 Cass Avenue, Lemont, IL, 60439, USA
| | - Nikita Gupta
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, IL, 60607, USA
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 Cass Avenue, Lemont, IL, 60439, USA
| | - Jonathan L Gesiorski
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, IL, 60607, USA
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 Cass Avenue, Lemont, IL, 60439, USA
| | - Ravindra B Weerasooriya
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, IL, 60607, USA
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 Cass Avenue, Lemont, IL, 60439, USA
| | - Ksenija D Glusac
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, IL, 60607, USA.
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 Cass Avenue, Lemont, IL, 60439, USA.
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5
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Tries A, Osella S, Zhang P, Xu F, Ramanan C, Kläui M, Mai Y, Beljonne D, Wang HI. Experimental Observation of Strong Exciton Effects in Graphene Nanoribbons. NANO LETTERS 2020; 20:2993-3002. [PMID: 32207957 PMCID: PMC7311082 DOI: 10.1021/acs.nanolett.9b04816] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 03/21/2020] [Indexed: 05/29/2023]
Abstract
Graphene nanoribbons (GNRs) with atomically precise width and edge structures are a promising class of nanomaterials for optoelectronics, thanks to their semiconducting nature and high mobility of charge carriers. Understanding the fundamental static optical properties and ultrafast dynamics of charge carrier generation in GNRs is essential for optoelectronic applications. Combining THz spectroscopy and theoretical calculations, we report a strong exciton effect with binding energy up to ∼700 meV in liquid-phase-dispersed GNRs with a width of 1.7 nm and an optical band gap of ∼1.6 eV, illustrating the intrinsically strong Coulomb interactions between photogenerated electrons and holes. By tracking the exciton dynamics, we reveal an ultrafast formation of excitons in GNRs with a long lifetime over 100 ps. Our results not only reveal fundamental aspects of excitons in GNRs (strong binding energy and ultrafast exciton formation etc.) but also highlight promising properties of GNRs for optoelectronic devices.
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Affiliation(s)
- Alexander Tries
- Max
Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
- Institute
of Physics and Graduate School of Excellence Material Sciences in
Mainz, Johannes Gutenberg-University Mainz, D-55128 Mainz, Germany
| | - Silvio Osella
- Chemical
and Biological Systems Simulation Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Pengfei Zhang
- School
of Chemistry and Chemical Engineering, Frontiers Science Center for
Transformative Molecules, Shanghai Jiao
Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Fugui Xu
- School
of Chemistry and Chemical Engineering, Frontiers Science Center for
Transformative Molecules, Shanghai Jiao
Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Charusheela Ramanan
- Max
Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Mathias Kläui
- Institute
of Physics and Graduate School of Excellence Material Sciences in
Mainz, Johannes Gutenberg-University Mainz, D-55128 Mainz, Germany
| | - Yiyong Mai
- School
of Chemistry and Chemical Engineering, Frontiers Science Center for
Transformative Molecules, Shanghai Jiao
Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - David Beljonne
- Laboratory
for Chemistry of Novel Materials, Université
de Mons, Place du Parc,
20, B-7000 Mons, Belgium
| | - Hai I. Wang
- Max
Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
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Han S, Boguschewski C, Gao Y, Xiao L, Zhu J, van Loosdrecht PHM. Incoherent phonon population and exciton-exciton annihilation dynamics in monolayer WS 2 revealed by time-resolved Resonance Raman scattering. OPTICS EXPRESS 2019; 27:29949-29961. [PMID: 31684250 DOI: 10.1364/oe.27.029949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 08/18/2019] [Indexed: 06/10/2023]
Abstract
Atomically thin layer transition metal dichalcogenides have been intensively investigated for their rich optical properties and potential applications on nano-electronics. In this work, we study the incoherent phonon and exciton population dynamics in monolayer WS2 by time-resolved Resonance Raman scattering spectroscopy. Upon excitation of the exciton transition, both Stokes and anti-Stokes scattering strength of the optical and the longitudinal acoustic two phonon modes exhibit large reduction. Based on the assumption of quasi-equilibrium distribution, the hidden phonon population dynamics is retrieved, which shows an instant build-up and a relaxation lifetime of ∼4 ps at the exciton density ∼1012cm-2. A phonon temperature rises of ∼20 K was identified due to the exciton excitation and relaxation. The exciton relaxation dynamics extracted from the transient vibrational Raman response shows strong excitation density dependence, signaling an important bi-molecular contribution to the decay. These results provide significant knowledge on the thermal dynamics after optical excitation, enhance the understanding of the fundamental exciton dynamics in two-dimensional transition metal materials, and demonstrate that time-resolved Resonance Raman scattering spectroscopy is a powerful method for exploring quasi-particle dynamics in optical materials.
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Pfeiffer M, Senkovskiy BV, Haberer D, Fischer FR, Yang F, Meerholz K, Ando Y, Grüneis A, Lindfors K. Observation of Room-Temperature Photoluminescence Blinking in Armchair-Edge Graphene Nanoribbons. NANO LETTERS 2018; 18:7038-7044. [PMID: 30336056 DOI: 10.1021/acs.nanolett.8b03006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
By enhancing the photoluminescence from aligned seven-atom wide armchair-edge graphene nanoribbons using plasmonic nanoantennas, we are able to observe blinking of the emission. The on- and off-times of the blinking follow power law statistics. In time-resolved spectra, we observe spectral diffusion. These findings together are a strong indication of the emission originating from a single quantum emitter. The room temperature photoluminescence displays a narrow spectral width of less than 50 meV, which is significantly smaller than the previously observed ensemble line width of 0.8 eV. From spectral time traces, we identify three optical transitions, which are energetically situated below the lowest bulk excitonic state E11 of the nanoribbons. We attribute the emission to transitions involving Tamm states localized at the end of the nanoribbon. The photoluminescence from a single ribbon is strongly enhanced when its end is in the antenna hot spot resulting in the observed single molecule characteristics of the emission. Our findings illustrate the essential role of the end termination of graphene nanoribbons in light emission and allow us to construct a model for photoluminescence from nanoribbons.
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Affiliation(s)
- Markus Pfeiffer
- Department für Chemie , Universität zu Köln , Luxemburger Strasse 116 , 50939 Köln , Germany
| | - Boris V Senkovskiy
- II. Physikalisches Institut , Universität zu Köln , Zülpicher Strasse 77 , 50937 Köln , Germany
| | - Danny Haberer
- Department of Chemistry , University of California at Berkeley , Tan Hall 680 , Berkeley , California 94720 , United States
| | - Felix R Fischer
- Department of Chemistry , University of California at Berkeley , Tan Hall 680 , Berkeley , California 94720 , United States
| | - Fan Yang
- II. Physikalisches Institut , Universität zu Köln , Zülpicher Strasse 77 , 50937 Köln , Germany
| | - Klaus Meerholz
- Department für Chemie , Universität zu Köln , Luxemburger Strasse 116 , 50939 Köln , Germany
| | - Yoichi Ando
- II. Physikalisches Institut , Universität zu Köln , Zülpicher Strasse 77 , 50937 Köln , Germany
| | - Alexander Grüneis
- II. Physikalisches Institut , Universität zu Köln , Zülpicher Strasse 77 , 50937 Köln , Germany
| | - Klas Lindfors
- Department für Chemie , Universität zu Köln , Luxemburger Strasse 116 , 50939 Köln , Germany
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