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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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2
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2N+4-rule and an atlas of bulk optical resonances of zigzag graphene nanoribbons. Nat Commun 2020; 11:82. [PMID: 31900390 PMCID: PMC6941967 DOI: 10.1038/s41467-019-13728-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 11/21/2019] [Indexed: 11/08/2022] Open
Abstract
Development of on-chip integrated carbon-based optoelectronic nanocircuits requires fast and non-invasive structural characterization of their building blocks. Recent advances in synthesis of single wall carbon nanotubes and graphene nanoribbons allow for their use as atomically precise building blocks. However, while cataloged experimental data are available for the structural characterization of carbon nanotubes, such an atlas is absent for graphene nanoribbons. Here we theoretically investigate the optical absorption resonances of armchair carbon nanotubes and zigzag graphene nanoribbons continuously spanning the tube (ribbon) transverse sizes from 0.5(0.4) nm to 8.1(12.8) nm. We show that the linear mapping is guaranteed between the tube and ribbon bulk resonance when the number of atoms in the tube unit cell is [Formula: see text], where [Formula: see text] is the number of atoms in the ribbon unit cell. Thus, an atlas of carbon nanotubes optical transitions can be mapped to an atlas of zigzag graphene nanoribbons.
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3
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Talirz L, Söde H, Kawai S, Ruffieux P, Meyer E, Feng X, Müllen K, Fasel R, Pignedoli CA, Passerone D. Band Gap of Atomically Precise Graphene Nanoribbons as a Function of Ribbon Length and Termination. Chemphyschem 2019; 20:2348-2353. [PMID: 31304992 DOI: 10.1002/cphc.201900313] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 07/09/2019] [Indexed: 11/11/2022]
Abstract
We study the band gap of finite N A = 7 armchair graphene nanoribbons (7-AGNRs) on Au(111) through scanning tunneling microscopy/spectroscopy combined with density functional theory calculations. The band gap of 7-AGNRs with lengths of 8 nm and more is converged to within 50 meV of its bulk value of ≈ 2 . 3 eV , while the band gap opens by several hundred meV in very short 7-AGNRs. We demonstrate that even an atomic defect, such as the addition of one hydrogen atom at the termini, has a significant effect - in this case, lowering the band gap. The effect can be captured in terms of a simple analytical model by introducing an effective "electronic length".
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Affiliation(s)
- Leopold Talirz
- nanotech@surfaces laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland.,Laboratory of Molecular Simulation (LSMO), Institut des Sciences et Ingenierie Chimiques, Valais, École Polytechnique Fédérale de, Lausanne, Sion, Switzerland
| | - Hajo Söde
- nanotech@surfaces laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
| | - Shigeki Kawai
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1, Namiki, Tsukuba, Ibaraki, 305-0044, Japan
| | - Pascal Ruffieux
- nanotech@surfaces laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
| | - Ernst Meyer
- Department of Physics and Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 82, Basel, Switzerland
| | - Xinliang Feng
- Max Planck Institute of Polymer Research, Mainz, Germany
| | - Klaus Müllen
- Max Planck Institute of Polymer Research, Mainz, Germany
| | - Roman Fasel
- nanotech@surfaces laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland.,Department of Chemistry and Biochemistry, University of, Bern, Switzerland
| | - Carlo A Pignedoli
- nanotech@surfaces laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
| | - Daniele Passerone
- nanotech@surfaces laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
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4
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Abstract
The optical excitations in layered phosphorene oxides are studied via ab initio calculation together with GW approximation for the self-energy and solving the Bethe-Salpeter equation (BSE) for the excitations. It is found that the electronic structure of phosphorene oxides closely depends on the oxygen concentration. For the high oxygen coverage structure P4O10, it shows a strong localized molecular-like electronic structure with exciton binding ( Eb) energy up to 3.0 eV, which is several times larger than the ordinary Eb value in various low-dimensional materials. This study may provide an alternative way to design functional layered materials with large exciton binding energies by controlling the oxidation level in phosphorene oxides.
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Affiliation(s)
- Yihua Lu
- School of Science and Engineering , Chinese University of Hong Kong Shenzhen , Shenzhen , Guangdong 518172 , China
| | - Xi Zhu
- School of Science and Engineering , Chinese University of Hong Kong Shenzhen , Shenzhen , Guangdong 518172 , China
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5
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Zhu J, German R, Senkovskiy BV, Haberer D, Fischer FR, Grüneis A, van Loosdrecht PHM. Exciton and phonon dynamics in highly aligned 7-atom wide armchair graphene nanoribbons as seen by time-resolved spontaneous Raman scattering. NANOSCALE 2018; 10:17975-17982. [PMID: 30226260 DOI: 10.1039/c8nr05950k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The opening of a band gap in graphene nanoribbons induces novel optical and electronic properties, strongly enhancing their application potential in nanoscale devices. Knowledge of the optical excitations and associated relaxation dynamics are essential for developing and optimizing device designs and functionality. Here we report on the optical excitations and associated relaxation dynamics in surface aligned 7-atom wide armchair graphene nanoribbons as seen by time-resolved spontaneous Stokes and anti-Stokes Raman scattering spectroscopy. On the anti-Stokes side we observe an optically induced increase of the scattering intensity of the Raman active optical phonons which we assign to changes in the optical phonon populations. The optical phonon population decays with a lifetime of ∼2 ps, indicating an efficient optical-acoustic phonon cooling mechanism. On the Stokes side we observe a substantial decrease of the phonon peak intensities which we relate to the dynamics of the optically induced exciton population. The exciton population shows a multi-exponential relaxation on the hundreds of ps time scale and is independent of the excitation intensity, indicating that exciton-exciton annihilation processes are not important and the exsistence of dark and trapped exciton states. Our results shed light on the optically induced phonon and exciton dynamics in surface aligned armchair graphene nanoribbons and demonstrate that time-resolved spontaneous Raman scattering spectroscopy is a powerful method for exploring quasi-particle dynamics in low dimensional materials.
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Affiliation(s)
- Jingyi Zhu
- Physics institute 2, University of Cologne, 50937, Germany.
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6
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Di Giovannantonio M, Deniz O, Urgel JI, Widmer R, Dienel T, Stolz S, Sánchez-Sánchez C, Muntwiler M, Dumslaff T, Berger R, Narita A, Feng X, Müllen K, Ruffieux P, Fasel R. On-Surface Growth Dynamics of Graphene Nanoribbons: The Role of Halogen Functionalization. ACS NANO 2018; 12:74-81. [PMID: 29200262 DOI: 10.1021/acsnano.7b07077] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
On-surface synthesis is a powerful route toward the fabrication of specific graphene-like nanostructures confined in two dimensions. This strategy has been successfully applied to the growth of graphene nanoribbons of diverse width and edge morphology. Here, we investigate the mechanisms driving the growth of 9-atom wide armchair graphene nanoribbons by using scanning tunneling microscopy, fast X-ray photoelectron spectroscopy, and temperature-programmed desorption techniques. Particular attention is given to the role of halogen functionalization (Br or I) of the molecular precursors. We show that the use of iodine-containing monomers fosters the growth of longer graphene nanoribbons (average length of 45 nm) due to a larger separation of the polymerization and cyclodehydrogenation temperatures. Detailed insight into the growth process is obtained by analysis of kinetic curves extracted from the fast X-ray photoelectron spectroscopy data. Our study provides fundamental details of relevance to the production of future electronic devices and highlights the importance of not only the rational design of molecular precursors but also the most suitable reaction pathways to achieve the desired final structures.
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Affiliation(s)
- Marco Di Giovannantonio
- Nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf, Switzerland
| | - Okan Deniz
- Nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf, Switzerland
| | - José I Urgel
- Nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf, Switzerland
| | - Roland Widmer
- Nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf, Switzerland
| | - Thomas Dienel
- Nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf, Switzerland
| | - Samuel Stolz
- Nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf, Switzerland
| | - Carlos Sánchez-Sánchez
- Nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf, Switzerland
| | | | - Tim Dumslaff
- Max Planck Institute for Polymer Research , 55128 Mainz, Germany
| | - Reinhard Berger
- Center for Advancing Electronics Dresden and Department of Chemistry and Food Chemistry, Technische Universität Dresden , 01062 Dresden, Germany
| | - Akimitsu Narita
- Max Planck Institute for Polymer Research , 55128 Mainz, Germany
| | - Xinliang Feng
- Center for Advancing Electronics Dresden and Department of Chemistry and Food Chemistry, Technische Universität Dresden , 01062 Dresden, Germany
| | - Klaus Müllen
- Max Planck Institute for Polymer Research , 55128 Mainz, Germany
| | - Pascal Ruffieux
- Nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf, Switzerland
| | - Roman Fasel
- Nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf, Switzerland
- Department of Chemistry and Biochemistry, University of Bern , 3012 Bern, Switzerland
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7
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Deniz O, Sánchez-Sánchez C, Dumslaff T, Feng X, Narita A, Müllen K, Kharche N, Meunier V, Fasel R, Ruffieux P. Revealing the Electronic Structure of Silicon Intercalated Armchair Graphene Nanoribbons by Scanning Tunneling Spectroscopy. NANO LETTERS 2017; 17:2197-2203. [PMID: 28301723 DOI: 10.1021/acs.nanolett.6b04727] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The electronic properties of graphene nanoribbons grown on metal substrates are significantly masked by the ones of the supporting metal surface. Here, we introduce a novel approach to access the frontier states of armchair graphene nanoribbons (AGNRs). The in situ intercalation of Si at the AGNR/Au(111) interface through surface alloying suppresses the strong contribution of the Au(111) surface state and allows for an unambiguous determination of the frontier electronic states of both wide and narrow band gap AGNRs. First-principles calculations provide insight into substrate induced screening effects, which result in a width-dependent band gap reduction for substrate-supported AGNRs. The strategy reported here provides a unique opportunity to elucidate the electronic properties of various kinds of graphene nanomaterials supported on metal substrates.
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Affiliation(s)
- Okan Deniz
- Empa, Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - Carlos Sánchez-Sánchez
- Empa, Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - Tim Dumslaff
- Max Planck Institute for Polymer Research , Ackermannweg 10, D-55128 Mainz, Germany
| | - Xinliang Feng
- Chair of Molecular Functional Materials, Department of Chemistry and Food Chemistry, Technische Universität Dresden , Mommsenstrasse 4, D-01062 Dresden, Germany
| | - Akimitsu Narita
- Max Planck Institute for Polymer Research , Ackermannweg 10, D-55128 Mainz, Germany
| | - Klaus Müllen
- Max Planck Institute for Polymer Research , Ackermannweg 10, D-55128 Mainz, Germany
| | - Neerav Kharche
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| | - Vincent Meunier
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| | - Roman Fasel
- Empa, Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
- Department of Chemistry and Biochemistry, University of Bern , Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Pascal Ruffieux
- Empa, Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
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8
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Abstract
The binding energy of an exciton in a semiconductor or an insulator is known to scale linearly with εr-2, where εr is its dielectric constant. In graphene however, since the kinetic energy scales linearly with the wave number instead of its square, the exciton binding energy is thus expected to scale with εr-1. In this work we make use of the configuration interaction approach to study the properties of excitons in graphene nanodots embedded in various dielectric environments. With tens of million configurations taken into account in the calculation, we find that the exciton binding energy can be well described by a single scaling rule in which the scaling factor is found to vary with the dimension of the nanodots as well as with the on-site interaction parameter, which agrees well with a recent experiment. The linear relation of the exciton binding energy found with the quasi-particle gap also agrees with the previous work on bulk graphene and other two-dimensional materials.
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Affiliation(s)
- Weidong Sheng
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China. and Collaborative Innovation Center of Advanced Microstructures, Nanjing, 210093, China
| | - Hao Wang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
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9
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Zhu X, Wang M. Scaling Law of Exciton Properties in the Surface Hydrogenated Armchair Graphene Nanoribbon. ChemistrySelect 2016. [DOI: 10.1002/slct.201600129] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Xi Zhu
- Division of Materials Science, School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
| | - Min Wang
- Institute for Clean Energy and Advanced Materials, Faculty of Materials and Energy; Southwest University; 2 Tiansheng Road Chongqing 400715 China
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10
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Kharche N, Meunier V. Width and Crystal Orientation Dependent Band Gap Renormalization in Substrate-Supported Graphene Nanoribbons. J Phys Chem Lett 2016; 7:1526-1533. [PMID: 27063190 DOI: 10.1021/acs.jpclett.6b00422] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The excitation energy levels of two-dimensional (2D) materials and their one-dimensional (1D) nanostructures, such as graphene nanoribbons (GNRs), are strongly affected by the presence of a substrate due to the long-range screening effects. We develop a first-principles approach combining density functional theory (DFT), the GW approximation, and a semiclassical image-charge model to compute the electronic band gaps in planar 1D systems in weak interaction with the surrounding environment. Application of our method to the specific case of GNRs yields good agreement with the range of available experimental data and shows that the band gap of substrate-supported GNRs are reduced by several tenths of an electronvolt compared to their isolated counterparts, with a width and orientation-dependent renormalization. Our results indicate that the band gaps in GNRs can be tuned by controlling screening at the interface by changing the surrounding dielectric materials.
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Affiliation(s)
- Neerav Kharche
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| | - Vincent Meunier
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
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11
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Zhu X, Wang M. Electronic and optical properties of surface hydrogenated armchair graphene nanoribbons: a theoretical study. RSC Adv 2016. [DOI: 10.1039/c5ra26686f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The hydrogen coverage on armchair graphene nanoribbons affects the spatial distribution of the wavefunction locally, revealing a confinement phenomenon, and influences the electronic and optical properties as well.
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Affiliation(s)
- Xi Zhu
- Division of Materials Science
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore 639798
- Singapore
| | - Min Wang
- Institute for Clean Energy & Advanced Materials
- Faculty of Materials and Energy
- Southwest University
- Chongqing 400715
- China
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12
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Wang M, Song SX, Zhao HX, Wang YC. Electronic and optical properties of surface-functionalized armchair graphene nanoribbons. RSC Adv 2016. [DOI: 10.1039/c5ra22701a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The functional groups on armchair graphene nanoribbons affect the spatial distribution of the wavefunction and influence the electronic and optical properties as well.
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Affiliation(s)
- Min Wang
- Institute for Clean Energy & Advanced Materials
- Faculty of Materials and Energy
- Southwest University
- Chongqing 400715
- P. R. China
| | - Si Xing Song
- Institute for Clean Energy & Advanced Materials
- Faculty of Materials and Energy
- Southwest University
- Chongqing 400715
- P. R. China
| | - Hai Xing Zhao
- Institute for Clean Energy & Advanced Materials
- Faculty of Materials and Energy
- Southwest University
- Chongqing 400715
- P. R. China
| | - Yu Chen Wang
- Institute for Clean Energy & Advanced Materials
- Faculty of Materials and Energy
- Southwest University
- Chongqing 400715
- P. R. China
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13
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Orbital-dependent Electron-Hole Interaction in Graphene and Associated Multi-Layer Structures. Sci Rep 2015; 5:17337. [PMID: 26610715 PMCID: PMC4661528 DOI: 10.1038/srep17337] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 10/28/2015] [Indexed: 11/08/2022] Open
Abstract
We develop an orbital-dependent potential to describe electron-hole interaction in materials with structural 2D character, i.e. quasi-2D materials. The modulated orbital-dependent potentials are also constructed with non-local screening, multi-layer screening, and finite gap due to the coupling with substrates. We apply the excitonic Hamiltonian in coordinate-space with developed effective electron-hole interacting potentials to compute excitons' binding strength at M (π band) and Γ (σ band) points in graphene and its associated multi-layer forms. The orbital-dependent potential provides a range-separated property for regulating both long- and short-range interactions. This accounts for the existence of the resonant π exciton in single- and bi-layer graphenes. The remarkable strong electron-hole interaction in σ orbitals plays a decisive role in the existence of σ exciton in graphene stack at room temperature. The interplay between gap-opening and screening from substrates shed a light on the weak dependence of σ exciton binding energy on the thickness of graphene stacks. Moreover, the analysis of non-hydrogenic exciton spectrum in quasi-2D systems clearly demonstrates the remarkable comparable contribution of orbital dependent potential with respect to non-local screening process. The understanding of orbital-dependent potential developed in this work is potentially applicable for a wide range of materials with low dimension.
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14
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Li X, Zhang TY, Su YJ. Periodically Modulated Size-Dependent Elastic Properties of Armchair Graphene Nanoribbons. NANO LETTERS 2015; 15:4883-4888. [PMID: 26134244 DOI: 10.1021/acs.nanolett.5b00399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
First-principles calculations were conducted on armchair graphene nanoribbons (AGNRs) to simulate the elastic behavior of AGNRs with hydrogen-terminated and bare edges. The results show width-dependent elastic properties with a periodicity of three, which depends on the nature of edge. The edge eigenstress and eigendisplacement models are able to predict the width-dependent nominal Young's modulus and Poisson's ratio, while the Clar structure explains the crucial role of edges in the periodically modulated size-dependent elastic properties.
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Affiliation(s)
- X Li
- †Corrosion and Protection Center, Key Laboratory for Environmental Fracture (MOE), University of Science and Technology Beijing, Beijing 100083, China
| | - Tong-Yi Zhang
- ‡Shanghai University Materials Genome Institute and Shanghai Materials Genome Institute, Shanghai University, 99 Shangda Road, Shanghai 200444, China
| | - Y J Su
- †Corrosion and Protection Center, Key Laboratory for Environmental Fracture (MOE), University of Science and Technology Beijing, Beijing 100083, China
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15
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Zhang Q, Jie J, Diao S, Shao Z, Zhang Q, Wang L, Deng W, Hu W, Xia H, Yuan X, Lee ST. Solution-processed graphene quantum dot deep-UV photodetectors. ACS NANO 2015; 9:1561-70. [PMID: 25625624 DOI: 10.1021/acsnano.5b00437] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Fast-response and high-sensitivity deep-ultraviolet (DUV) photodetectors with detection wavelength shorter than 320 nm are in high demand due to their potential applications in diverse fields. However, the fabrication processes of DUV detectors based on traditional semiconductor thin films are complicated and costly. Here we report a high-performance DUV photodetector based on graphene quantum dots (GQDs) fabricated via a facile solution process. The devices are capable of detecting DUV light with wavelength as short as 254 nm. With the aid of an asymmetric electrode structure, the device performance could be significantly improved. An on/off ratio of ∼6000 under 254 nm illumination at a relatively weak light intensity of 42 μW cm(-2) is achieved. The devices also exhibit excellent stability and reproducibility with a fast response speed. Given the solution-processing capability of the devices and extraordinary properties of GQDs, the use of GQDs will open up unique opportunities for future high-performance, low-cost DUV photodetectors.
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Affiliation(s)
- Qing Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University , Suzhou, Jiangsu 215123, P. R. China
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16
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Wang M, Wang YC, Zhao HX, Song SX. Optical properties of armchair graphene nanoribbons with Stone–Wales defects and hydrogenation on the defects. RSC Adv 2015. [DOI: 10.1039/c5ra08836d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Armchair graphene nanoribbons display interesting optical properties with the existence of Stone–Wales defects and hydrogenation on the defects.
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Affiliation(s)
- Min Wang
- Institute for Clean Energy & Advanced Materials
- Faculty of Materials and Energy
- Southwest University
- Chongqing 400715
- P. R. China
| | - Yu Chen Wang
- Institute for Clean Energy & Advanced Materials
- Faculty of Materials and Energy
- Southwest University
- Chongqing 400715
- P. R. China
| | - Hai Xing Zhao
- Institute for Clean Energy & Advanced Materials
- Faculty of Materials and Energy
- Southwest University
- Chongqing 400715
- P. R. China
| | - Si Xing Song
- Institute for Clean Energy & Advanced Materials
- Faculty of Materials and Energy
- Southwest University
- Chongqing 400715
- P. R. China
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17
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Sakaguchi H, Kawagoe Y, Hirano Y, Iruka T, Yano M, Nakae T. Width-controlled sub-nanometer graphene nanoribbon films synthesized by radical-polymerized chemical vapor deposition. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:4134-4138. [PMID: 24711068 DOI: 10.1002/adma.201305034] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 03/10/2014] [Indexed: 06/03/2023]
Abstract
Radical-polymerized chemical vapor deposition, a new bottom-up method, was developed to produce graphene nanoribbons (GNRs) efficiently, despite the use of extremely low vacuum. Using this technique, a systematic synthesis of a multilayered high-density array of width-controlled sub-1 nm GNRs on a metal surface, with width-dependent band gap, is made possible. GNR films transferred onto insulating substrates behave as an excellent photoconductor.
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Affiliation(s)
- Hiroshi Sakaguchi
- Institute of Advanced Energy, Kyoto University, Uji, 611-0011, Kyoto, Japan
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Kozawa D, Zhu X, Miyauchi Y, Mouri S, Ichida M, Su H, Matsuda K. Excitonic Photoluminescence from Nanodisc States in Graphene Oxides. J Phys Chem Lett 2014; 5:1754-1759. [PMID: 26270379 DOI: 10.1021/jz500516u] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The origin of near-infrared (NIR) luminescence from graphene oxide (GO) is investigated by photoluminescence (PL) excitation spectroscopy, time-resolved PL spectroscopy, and density functional theory based many body perturbation theories. The energy of experimentally observed NIR PL peak depends on the excitation energy, and the peak broadens with increasing excitation energy. It is found that the PL decay curves in time-resolved spectroscopy show build-up behavior at lower emission energies due to energy transfer between smaller to larger graphene nanodisc (GND) states embedded in GO. We demonstrate that the NIR PL originates from ensemble emission of GND states with a few nanometers in size. The theoretical calculations reveal the electronic and excitonic properties of individual GND states with various sizes, which accounts for the inhomogeneously broadened NIR PL. We further demonstrate that the electronic properties are highly sensitive to the protonation and deprotonation processes of GND states using both the experimental and theoretical approaches.
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Affiliation(s)
- Daichi Kozawa
- †Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Xi Zhu
- ‡School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
| | - Yuhei Miyauchi
- †Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
- §Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Shinichiro Mouri
- †Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Masao Ichida
- ∥Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Higashi-Nada-ku, Kobe 658-8501, Japan
| | - Haibin Su
- ‡School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
- ⊥Institute of Advanced Studies, Nanyang Technological University, 60 Nanyang View, 639673 Singapore
| | - Kazunari Matsuda
- †Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
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Abstract
Exciton characteristics in graphene epoxide (GE) are investigated by density functional theory with quasi-particle corrections and many-body interactions. The nature of the exciton is influenced by epoxide content and detailed geometric configurations. Two kinds of excitons are identified in GE: Frenkel-like exciton originated from the sp(2) carbon cluster and charge-transfer exciton formed by localized states involving both oxygen and carbon atoms. The unusual blue shift associated with the Frenkel-like exciton leaking is highlighted. One scaling relationship is proposed to address the power-law dependence of Frenkel-like exciton binding strength on its size. The charge-transfer exciton appears in GE samples with the high oxygen coverage. Particularly, the exciton in GE structures exhibits long lifetime by analyzing both radiative and nonradiative decay processes. This study sheds light on the potential applications of GE-based structures with attractive high quantum yield in light emission and optoelectronic technology.
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Affiliation(s)
- Xi Zhu
- Division of Materials Science, Nanyang Technological University , 50 Nanyang Avenue, 639798 Singapore
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20
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Lee D, Seo J, Zhu X, Lee J, Shin HJ, Cole JM, Shin T, Lee J, Lee H, Su H. Quantum confinement-induced tunable exciton states in graphene oxide. Sci Rep 2014; 3:2250. [PMID: 23872608 PMCID: PMC3718196 DOI: 10.1038/srep02250] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 07/04/2013] [Indexed: 11/24/2022] Open
Abstract
Graphene oxide has recently been considered to be a potential replacement for cadmium-based quantum dots due to its expected high fluorescence. Although previously reported, the origin of the luminescence in graphene oxide is still controversial. Here, we report the presence of core/valence excitons in graphene-based materials, a basic ingredient for optical devices, induced by quantum confinement. Electron confinement in the unreacted graphitic regions of graphene oxide was probed by high resolution X-ray absorption near edge structure spectroscopy and first-principles calculations. Using experiments and simulations, we were able to tune the core/valence exciton energy by manipulating the size of graphitic regions through the degree of oxidation. The binding energy of an exciton in highly oxidized graphene oxide is similar to that in organic electroluminescent materials. These results open the possibility of graphene oxide-based optoelectronic device technology.
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Affiliation(s)
- Dongwook Lee
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
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21
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Wang M, Li CM. Investigation of doping effects on magnetic properties of the hydrogenated and fluorinated graphene structures by extra charge mimic. Phys Chem Chem Phys 2013; 15:3786-92. [DOI: 10.1039/c3cp00071k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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