1
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Wang A, Jiang X, Zheng Q, Petek H, Zhao J. Ultrafast many-body bright-dark exciton transition in anatase TiO 2. Proc Natl Acad Sci U S A 2023; 120:e2307671120. [PMID: 37956295 PMCID: PMC10666115 DOI: 10.1073/pnas.2307671120] [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: 05/07/2023] [Accepted: 09/29/2023] [Indexed: 11/15/2023] Open
Abstract
The momentum-forbidden dark excitons can have a pivotal role in quantum information processing, Bose-Einstein condensation, and light-energy harvesting. Anatase TiO2 with an indirect band gap is a prototypical platform to study bright to momentum-forbidden dark exciton transition. Here, we examine, by GW plus the real-time Bethe-Salpeter equation combined with the nonadiabatic molecular dynamics (GW + rtBSE-NAMD), the many-body transition that occurs within 100 fs from the optically excited bright to the strongly bound momentum-forbidden dark excitons in anatase TiO2. Comparing with the single-particle picture in which the exciton transition is considered to occur through electron-phonon scattering, within the GW + rtBSE-NAMD framework, the many-body electron-hole Coulomb interaction activates additional exciton relaxation channels to notably accelerate the exciton transition in competition with other radiative and nonradiative processes. The existence of dark excitons and ultrafast bright-dark exciton transitions sheds insights into applications of anatase TiO2 in optoelectronic devices and light-energy harvesting as well as the formation process of dark excitons in semiconductors.
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Affiliation(s)
- Aolei Wang
- Department of Physics, University of Science and Technology of China, Hefei230026, China
| | - Xiang Jiang
- International Center for Quantum Design of Functional Materials/Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei230026, China
| | - Qijing Zheng
- Department of Physics, University of Science and Technology of China, Hefei230026, China
| | - Hrvoje Petek
- Department of Physics and Astronomy and the IQ Initiative, University of Pittsburgh, Pittsburgh, PA15260
| | - Jin Zhao
- Department of Physics, University of Science and Technology of China, Hefei230026, China
- International Center for Quantum Design of Functional Materials/Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei230026, China
- Department of Physics and Astronomy and the IQ Initiative, University of Pittsburgh, Pittsburgh, PA15260
- Hefei National Laboratory, University of Science and Technology of China, Hefei230088, China
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2
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Huang W, Zhong J, Sheng W, Zhou A. Tuning of excitons in phosphorene atomic chains. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 36:075301. [PMID: 37879347 DOI: 10.1088/1361-648x/ad06f1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 10/25/2023] [Indexed: 10/27/2023]
Abstract
An universal scaling between the exciton binding energy and quasiparticle (QP) band gap was first discovered in two-dimensional (2D) semiconductors such as graphene derivatives, various transition materials dichalcogenides, and black phosphorus (Choiet al2015Phys. Rev. Lett.115066403; Jianget al2017Phys. Rev. Lett.118266401), and later extended to quasi one-dimensional (1D) systems such as carbon nanotubes and graphene nanoribbons. In this work we study the excitonic states in phosphorene atomic chains by using the exact diagonalization method and show that the linear scaling between the exciton binding energy (Ex) and QP shift (Δqs) can be easily tuned by the dielectric environment. In the presence of weak screening,Exis seen to increase withΔqsand exhibits a similar scaling as those 2D materials. As the screening becomes stronger, however, the dependence is found to be reversed, i.e.Exnow decreases whenΔqsincreases. More interestingly, we also reveal thatExmay even become nearly constant, independent on the system dimension andΔqswhen the screening reaches a certain strength. These abnormal scaling relations are attributed to the complex nature of excitons in the strongly correlated 1D system.
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Affiliation(s)
- Wenzhuo Huang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
| | - Jun Zhong
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
| | - Weidong Sheng
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
| | - Aiping Zhou
- Department of Mathematics and Physics, Nanjing Institute of Technology, Nanjing 211167, People's Republic of China
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3
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Cassiano TDSA, Júnior LAR, Silva GME, Neto PHDO. Regulating Polaron Transport Regime via Heterojunction Engineering in Cove‐Type Graphene Nanoribbons. ADVANCED THEORY AND SIMULATIONS 2023. [DOI: 10.1002/adts.202200877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
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4
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Abu UO, Akter S, Nepal B, Pitton KA, Guiton BS, Strachan DR, Sumanasekera G, Wang H, Jasinski JB. Ultra-Narrow Phosphorene Nanoribbons Produced by Facile Electrochemical Process. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2203148. [PMID: 36068163 PMCID: PMC9631066 DOI: 10.1002/advs.202203148] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Phosphorene nanoribbons (PNRs) have inspired strong research interests to explore their exciting properties that are associated with the unique two-dimensional (2D) structure of phosphorene as well as the additional quantum confinement of the nanoribbon morphology, providing new materials strategy for electronic and optoelectronic applications. Despite several important properties of PNRs, the production of these structures with narrow widths is still a great challenge. Here, a facile and straightforward approach to synthesize PNRs via an electrochemical process that utilize the anisotropic Na+ diffusion barrier in black phosphorus (BP) along the [001] zigzag direction against the [100] armchair direction, is reported. The produced PNRs display widths of good uniformity (10.3 ± 3.8 nm) observed by high-resolution transmission electron microscopy, and the suppressed B2g vibrational mode from Raman spectroscopy results. More interestingly, when used in field-effect transistors, synthesized bundles exhibit the n-type behavior, which is dramatically different from bulk BP flakes which are p-type. This work provides insights into a new synthesis approach of PNRs with confined widths, paving the way toward the development of phosphorene and other highly anisotropic nanoribbon materials for high-quality electronic applications.
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Affiliation(s)
- Usman O. Abu
- Conn Center for Renewable Energy ResearchUniversity of LouisvilleLouisvilleKY40292USA
| | - Sharmin Akter
- Department of Mechanical EngineeringUniversity of LouisvilleLouisvilleKY40292USA
| | - Bimal Nepal
- Department of Physics and AstronomyUniversity of LouisvilleLouisvilleKY40292USA
| | - Kathryn A. Pitton
- Department of ChemistryUniversity of Kentucky125 Chemistry–Physics BuildingLexingtonKY40506‐0055USA
| | - Beth S. Guiton
- Department of ChemistryUniversity of Kentucky125 Chemistry–Physics BuildingLexingtonKY40506‐0055USA
| | - Douglas R. Strachan
- Department of Physics and AstronomyUniversity of Kentucky177 Chemistry–Physics BuildingLexingtonKY40506‐0055USA
| | - Gamini Sumanasekera
- Department of Physics and AstronomyUniversity of LouisvilleLouisvilleKY40292USA
| | - Hui Wang
- Department of Mechanical EngineeringUniversity of LouisvilleLouisvilleKY40292USA
| | - Jacek B. Jasinski
- Conn Center for Renewable Energy ResearchUniversity of LouisvilleLouisvilleKY40292USA
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5
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Ge Y, Fisher TS. First-principles calculations of the optical response of single-layer and bilayer armchair graphene nanoribbons. FRONTIERS IN NANOTECHNOLOGY 2022. [DOI: 10.3389/fnano.2022.999292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Electronic and optical properties of single-layer and bilayer armchair graphene nanoribbons are investigated using a first-principles method. Increased nanoribbon width reduces the band gap and causes a red shift in photon absorption energy. The 3n + 2 family of nanoribbons has the smallest band gaps and lowest onset photon absorption energy among the three families considered due to high π-conjugation indicated by exciton wavefunctions. We also compare the bilayer α and β alignments of armchair graphene nanoribbons with their single-layer counterparts. The extra layer of graphene reduces the band gap and onset photon absorption energy, and the difference between the α alignment and the single-layer configuration is more significant than that of the β alignment and the single layer. Our calculations indicate that the optical properties of graphene nanoribbons depend on the details of atomic structures, including nanoribbon width, edge alignment and number of layers. These characteristics are expected to be important in the design of optoelectronic devices.
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6
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Kumar S, Pratap S, Kumar V, Mishra RK, Gwag JS, Chakraborty B. Electronic, transport, magnetic and optical properties of graphene nanoribbons review. LUMINESCENCE 2022. [PMID: 35850156 DOI: 10.1002/bio.4334] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/03/2022] [Accepted: 06/14/2022] [Indexed: 11/08/2022]
Abstract
Low dimensional materials have attracted great research interest from both theoretical and experimental point of view. These materials exhibit novel physical and chemical properties due to the confinement effect in low dimensions. The experimental observations of graphene open a new platform to study the physical properties of materials restricted to two dimensions. This featured article provides a review on the novel properties of quasi one-dimensional (1D) material known as graphene nanoribbon. Graphene nanoribbons can be obtained by unzipping carbon nanotubes (CNTs) or cutting the graphene sheet. Alternatively, it is also called the finite termination of graphene edges. It gives rise different edge geometries namely zigzag and armchair among others. There are various physical and chemical techniques to realize these materials. Depending on the edge type termination, these are called the zigzag and armchair graphene nanoribbons (ZGNR and AGNR). These edges play an important role in controlling the properties of graphene nanoribbons. The present review article provides an overview of the electronic, transport, optical and magnetic properties of graphene nanoribbons. However, there are different ways to tune these properties for device applications. Here, some of them are highlighted such as external perturbations and chemical modifications. Few applications of graphene nanoribbon have and chemical modifications. Few applications of graphene nanoribbon have also been briefly discussed.
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Affiliation(s)
- Sandeep Kumar
- Department of Physics and astronomical Science, Central University of Himachal Pradesh, Kangra, H.P, India
| | - Surender Pratap
- Department of Physics and astronomical Science, Central University of Himachal Pradesh, Kangra, H.P, India
| | - Vipin Kumar
- Department of Physics, Yeungnam University, Gyeongsan, South Korea
| | | | - Jin Seog Gwag
- Department of Physics, Yeungnam University, Gyeongsan, South Korea
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7
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Liu Z, Fu S, Liu X, Narita A, Samorì P, Bonn M, Wang HI. Small Size, Big Impact: Recent Progress in Bottom-Up Synthesized Nanographenes for Optoelectronic and Energy Applications. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2106055. [PMID: 35218329 PMCID: PMC9259728 DOI: 10.1002/advs.202106055] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/31/2022] [Indexed: 05/20/2023]
Abstract
Bottom-up synthesized graphene nanostructures, including 0D graphene quantum dots and 1D graphene nanoribbons, have recently emerged as promising candidates for efficient, green optoelectronic, and energy storage applications. The versatility in their molecular structures offers a large and novel library of nanographenes with excellent and adjustable optical, electronic, and catalytic properties. In this minireview, recent progress on the fundamental understanding of the properties of different graphene nanostructures, and their state-of-the-art applications in optoelectronics and energy storage are summarized. The properties of pristine nanographenes, including high emissivity and intriguing blinking effect in graphene quantum dots, superior charge transport properties in graphene nanoribbons, and edge-specific electrochemistry in various graphene nanostructures, are highlighted. Furthermore, it is shown that emerging nanographene-2D material-based van der Waals heterostructures provide an exciting opportunity for efficient green optoelectronics with tunable characteristics. Finally, challenges and opportunities of the field are highlighted by offering guidelines for future combined efforts in the synthesis, assembly, spectroscopic, and electrical studies as well as (nano)fabrication to boost the progress toward advanced device applications.
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Affiliation(s)
- Zhaoyang Liu
- University of StrasbourgCNRSISIS UMR 70068 allée Gaspard MongeStrasbourg67000France
| | - Shuai Fu
- Max Planck Institute for Polymer ResearchAckermannweg 10Mainz55128Germany
| | - Xiaomin Liu
- Max Planck Institute for Polymer ResearchAckermannweg 10Mainz55128Germany
| | - Akimitsu Narita
- Max Planck Institute for Polymer ResearchAckermannweg 10Mainz55128Germany
- Organic and Carbon Nanomaterials UnitOkinawa Institute of Science and Technology Graduate University1919‐1 Tancha, Onna‐sonKunigamiOkinawa904‐0495Japan
| | - Paolo Samorì
- University of StrasbourgCNRSISIS UMR 70068 allée Gaspard MongeStrasbourg67000France
| | - Mischa Bonn
- Max Planck Institute for Polymer ResearchAckermannweg 10Mainz55128Germany
| | - Hai I. Wang
- Max Planck Institute for Polymer ResearchAckermannweg 10Mainz55128Germany
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8
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Fuller J, Phillips W, An Q, Gakhar R. Local Coordination Environment of 3d and 4d Transition Metal Ions in LiCl-KCl Eutectic Mixture. MATERIALS 2022; 15:ma15041478. [PMID: 35208016 PMCID: PMC8877717 DOI: 10.3390/ma15041478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/08/2022] [Accepted: 02/09/2022] [Indexed: 01/27/2023]
Abstract
In this study, the structure and coordination environment of two 3d transition elements (Ni and Cr) is investigated in a molten chloride salt system. Electronic absorption spectroscopy was employed to elucidate their coordination environment in 3LiCl-2KCl eutectic salt, as a function of temperature. Density functional theory (DFT) modeling was used to determine the coordination environment of the transition metal species in the eutectic composition as well as the optical spectra computationally. The Ni2+and Cr3+ exist in a tetrahedral and octahedral coordination environment, respectively, in eutectic salt. The spectra thus obtained were compared with the experimental data; a reasonable qualitative agreement was obtained between experimental and computational Ni2+ and Cr3+spectra, and the coordination of both elements in the eutectic composition were in excellent agreement with the experimentally determined results. Computational results were also obtained for two 4d elements, Mo3+ and Nb3+, with both quantum molecular dynamics (QMD) and hybrid functional optical spectra indicating octahedral coordination.
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Affiliation(s)
- Jon Fuller
- Idaho National Laboratory, Pyrochemistry and Molten Salt Systems Department, Idaho Falls, ID 83415, USA; (J.F.); (W.P.)
- Department of Chemical and Materials Engineering, University of Nevada, Reno, NV 89577, USA
| | - William Phillips
- Idaho National Laboratory, Pyrochemistry and Molten Salt Systems Department, Idaho Falls, ID 83415, USA; (J.F.); (W.P.)
| | - Qi An
- Department of Chemical and Materials Engineering, University of Nevada, Reno, NV 89577, USA
- Correspondence: (Q.A.); (R.G.)
| | - Ruchi Gakhar
- Idaho National Laboratory, Pyrochemistry and Molten Salt Systems Department, Idaho Falls, ID 83415, USA; (J.F.); (W.P.)
- Correspondence: (Q.A.); (R.G.)
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9
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Yao Y, Golze D, Rinke P, Blum V, Kanai Y. All-Electron BSE@ GW Method for K-Edge Core Electron Excitation Energies. J Chem Theory Comput 2022; 18:1569-1583. [PMID: 35138865 DOI: 10.1021/acs.jctc.1c01180] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We present an accurate computational approach to calculate absolute K-edge core electron excitation energies as measured by X-ray absorption spectroscopy. Our approach employs an all-electron Bethe-Salpeter equation (BSE) formalism based on GW quasiparticle energies (BSE@GW) using numeric atom-centered orbitals (NAOs). The BSE@GW method has become an increasingly popular method for the computation of neutral valence excitation energies of molecules. However, it was so far not applied to molecular K-edge excitation energies. We discuss the influence of different numerical approximations on the BSE@GW calculation and employ in our final setup (i) exact numeric algorithms for the frequency integration of the GW self-energy, (ii) G0W0 and BSE starting points with ∼50% of exact exchange, (iii) the Tamm-Dancoff approximation and (iv) relativistic corrections. We study the basis set dependence and convergence with common Gaussian-type orbital and NAO basis sets. We identify the importance of additional spatially confined basis functions as well as of diffuse augmenting basis functions. The accuracy of our BSE@GW method is assessed for a benchmark set of small organic molecules, previously used for benchmarking the equation-of-motion coupled cluster method [Peng et al., J. Chem. Theory Comput., 2015, 11, 4146], as well as the medium-sized dibenzothiophene (DBT) molecule. Our BSE@GW results for absolute excitation energies are in excellent agreement with the experiment, with a mean average error of only 0.63 eV for the benchmark set and with errors <1 eV for the DBT molecule.
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Affiliation(s)
- Yi Yao
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Dorothea Golze
- Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, 01062 Dresden, Germany.,Department of Applied Physics, Aalto University, P.O. Box 11100, FI-00076 Aalto, Finland
| | - Patrick Rinke
- Department of Applied Physics, Aalto University, P.O. Box 11100, FI-00076 Aalto, Finland
| | | | - Yosuke Kanai
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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10
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Kim J, Lee N, Choi D, Kim DY, Kawai R, Yamada Y. Pentagons and Heptagons on Edges of Graphene Nanoflakes Analyzed by X-ray Photoelectron and Raman Spectroscopy. J Phys Chem Lett 2021; 12:9955-9962. [PMID: 34617766 DOI: 10.1021/acs.jpclett.1c02524] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Identifying pentagons and heptagons in graphene nanoflake (GNF) structures at the atomic scale is important to completely understand the chemical and physical properties of these materials. Herein, we used X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy to analyze the spectral features of GNFs according to the position of pentagons and heptagons introduced onto their zigzag and armchair edges. The XPS peak maxima were shifted to higher binding energies by introducing the pentagons or heptagons on armchair rather than zigzag edges, and the structures could be distinguished depending on the positions of the introduced pentagons or heptagons. Raman spectroscopic analyses also revealed that the position of edges with introduced pentagons or heptagons could also be identified using Raman spectroscopy, with characteristic bands appearing at 800-1200 cm-1, following the introduction of either pentagons or heptagons on armchair edges. This precise spectroscopic identification of pentagons and heptagons in GNFs provides the groundwork for the analysis of graphene-related materials.
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Affiliation(s)
- Jungpil Kim
- Carbon Materials Application Research Group, Korea Institute of Industrial Technology (KITECH), 222 Palbok-ro, Deokjin-gu, Jeonju 54853, Republic of Korea
| | - Nodo Lee
- Materials & Devices Advanced Research Institute, LG Electronics, 10, Magokjungang-ro, Gangseo-gu, Seoul 07796, Republic of Korea
| | - Duyoung Choi
- Carbon Materials Application Research Group, Korea Institute of Industrial Technology (KITECH), 222 Palbok-ro, Deokjin-gu, Jeonju 54853, Republic of Korea
| | - Dong Young Kim
- Department of Applied Chemistry, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Ryouhei Kawai
- Graduate School of Engineering, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan
| | - Yasuhiro Yamada
- Graduate School of Engineering, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan
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11
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Deily Nazar N, Vazifehshenas T, Ebrahimi MR, Peeters FM. Strong anisotropic optical properties of 8- Pmmn borophene: a many-body perturbation study. Phys Chem Chem Phys 2021; 23:16417-16422. [PMID: 34318830 DOI: 10.1039/d1cp01910d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using first-principles many-body perturbation theory, we investigate the optical properties of 8-Pmmn borophene at two levels of approximations; the GW method considering only the electron-electron interaction and the GW in combination with the Bethe-Salpeter equation including electron-hole coupling. The band structure exhibits anisotropic Dirac cones with semimetallic character. The optical absorption spectra are obtained for different light polarizations and we predict strong optical absorbance anisotropy. The absorption peaks undergo a global redshift when the electron-hole interaction is taken into account due to the formation of bound excitons which have an anisotropic excitonic wave function.
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Affiliation(s)
- N Deily Nazar
- Department of Physics, Shahid Beheshti University, G. C., Evin, Tehran 1983969411, Iran.
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12
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Meftakhutdinov RM, Sibatov RT, Kochaev AI. Graphenylene nanoribbons: electronic, optical and thermoelectric properties from first-principles calculations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:345301. [PMID: 32303006 DOI: 10.1088/1361-648x/ab8a9f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 04/17/2020] [Indexed: 06/11/2023]
Abstract
Recently synthesized two-dimensional graphene-like material referred to as graphenylene is a semiconductor with a narrow direct bandgap that holds great promise for nanoelectronic applications. The significant bandgap increase can be provided by the strain applied to graphenylene crystal lattice or by using nanoribbons instead of extended layers. In this paper, we present the systematic study of the electronic, optical and thermoelectric properties of graphenylene nanoribbons using calculations based on the density functional theory. Estimating the binding energies, we substantiate the stability of nanoribbons with zigzag and armchair edges passivated by hydrogen atoms. Electronic spectra indicate that all considered structures could be classified as direct bandgap semiconductors. From the calculated dependence of bandgap on nanoribbon width we observe the identical scaling rule for armchair and zigzag graphenylene ribbons. A family-based classification used for the electronic structure of armchair graphene nanoribbons can not be extended to the case of graphenylene ones. The absorption coefficient, optical conductivity, and complex refractive index are calculated by means of the first-principles methods and the Kubo-Greenwood formula. It has been shown that graphenylene ribbons effectively absorb visible-range electromagnetic waves. Due to this absorption the conductivity is noticeably increased in this range. The transport coefficients and thermoelectric figure of merit are calculated by the nonequilibrium Green functions method. Summarizing the results, we discuss the possible use of graphenylene films and nanoribbons in nanoelectronic devices.
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Affiliation(s)
| | - R T Sibatov
- Ulyanovsk State University, Ulyanovsk, Russia
- Institute of Nanotechnology of Microelectronics of the Russian Academy of Sciences (INME RAS), Moscow, Russia
| | - A I Kochaev
- Ulyanovsk State University, Ulyanovsk, Russia
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13
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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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14
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Ma C, Xiao Z, Puretzky AA, Wang H, Mohsin A, Huang J, Liang L, Luo Y, Lawrie BJ, Gu G, Lu W, Hong K, Bernholc J, Li AP. Engineering Edge States of Graphene Nanoribbons for Narrow-Band Photoluminescence. ACS NANO 2020; 14:5090-5098. [PMID: 32283017 DOI: 10.1021/acsnano.0c01737] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Solid-state narrow-band light emitters are on-demand for quantum optoelectronics. Current approaches based on defect engineering in low-dimensional materials usually introduce a broad range of emission centers. Here, we report narrow-band light emission from covalent heterostructures fused to the edges of graphene nanoribbons (GNRs) by controllable on-surface reactions from molecular precursors. Two types of heterojunction (HJ) states are realized by sequentially synthesizing GNRs and graphene nanodots (GNDs) and then coupling them together. HJs between armchair GNDs and armchair edges of the GNR are coherent and give rise to narrow-band photoluminescence. In contrast, HJs between the armchair GNDs and the zigzag ends of GNRs are defective and give rise to nonradiative states near the Fermi level. At low temperatures, sharp photoluminescence emissions with peak energy range from 2.03 to 2.08 eV and line widths of 2-5 meV are observed. The radiative HJ states are uniform, and the optical transition energy is controlled by the band gaps of GNRs and GNDs. As these HJs can be synthesized in a large quantity with atomic precision, this finding highlights a route to programmable and deterministic creation of quantum light emitters.
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Affiliation(s)
- Chuanxu Ma
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
- 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
| | - Zhongcan Xiao
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Alexander A Puretzky
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Hao Wang
- Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Ali Mohsin
- Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Jingsong Huang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Liangbo Liang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Yingdong Luo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Benjamin J Lawrie
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Gong Gu
- Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Wenchang Lu
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, United States
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Kunlun Hong
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jerzy Bernholc
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, United States
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - An-Ping Li
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
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15
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Zhao S, Barin GB, Cao T, Overbeck J, Darawish R, Lyu T, Drapcho S, Wang S, Dumslaff T, Narita A, Calame M, Müllen K, Louie SG, Ruffieux P, Fasel R, Wang F. Optical Imaging and Spectroscopy of Atomically Precise Armchair Graphene Nanoribbons. NANO LETTERS 2020; 20:1124-1130. [PMID: 31916444 DOI: 10.1021/acs.nanolett.9b04497] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report the optical imaging and absorption spectroscopy on atomically precise armchair graphene nanoribbons (GNRs) on insulating fused silica substrates. This is achieved by controlling light polarization on macroscopically aligned GNRs which greatly enhances the optical contrast of the submonolayer GNRs on the insulating substrates. We measure the linear absorption spectra of 7-armchair and 9-armchair GNRs in this study, and the experimental data agree qualitatively with ab inito calculation results. The polarization spectroscopy technique enables an unambiguous optical identification of GNRs and provides a rapid tool to characterize the transferred film over a large area.
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Affiliation(s)
- Sihan Zhao
- Department of Physics , University of California at Berkeley , Berkeley , California 94720 , United States
| | - Gabriela Borin Barin
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland
| | - Ting Cao
- Department of Physics , University of California at Berkeley , Berkeley , California 94720 , United States
- Department of Materials Science and Engineering , University of Washington , Seattle , Washington United States
| | - Jan Overbeck
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland
| | - Rimah Darawish
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland
| | - Tairu Lyu
- Department of Physics , University of California at Berkeley , Berkeley , California 94720 , United States
| | - Steve Drapcho
- Department of Physics , University of California at Berkeley , Berkeley , California 94720 , United States
| | - Sheng Wang
- Department of Physics , University of California at Berkeley , Berkeley , California 94720 , United States
- Materials Science Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Tim Dumslaff
- Max Planck Institute for Polymer Research , Ackermannweg 10 , D-55128 Mainz , Germany
| | - Akimitsu Narita
- Max Planck Institute for Polymer Research , Ackermannweg 10 , D-55128 Mainz , Germany
| | - Michel Calame
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland
| | - Klaus Müllen
- Max Planck Institute for Polymer Research , Ackermannweg 10 , D-55128 Mainz , Germany
- Institute of Physical Chemistry , Johannes Gutenberg-Universität Mainz , 5128 Mainz , Germany
| | - Steven G Louie
- Department of Physics , University of California at Berkeley , Berkeley , California 94720 , United States
- Materials Science Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Pascal Ruffieux
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland
| | - Roman Fasel
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland
- Department of Chemistry and Biochemistry , University of Bern , Freiestrasse 3 , CH-3012 Bern , Switzerland
| | - Feng Wang
- Department of Physics , University of California at Berkeley , Berkeley , California 94720 , United States
- Materials Science Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- Kavli Energy NanoSciences Institute , University of California, Berkeley and the Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
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16
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Xie H, Fang S, Zhao H, Xu X, Ye N, Zhuang W. Quasiparticle effects on the linear and nonlinear susceptibility of ZnGeP 2. RSC Adv 2019; 9:35771-35779. [PMID: 35528062 PMCID: PMC9074718 DOI: 10.1039/c9ra08172k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 10/28/2019] [Indexed: 11/22/2022] Open
Abstract
The semiconductor zinc germanium diphosphide (ZnGeP2) has wide applications in the infrared nonlinear optics (NLO) due to its high nonlinear optical coefficient, wide infrared transparency range and high thermal conductivity. Absorptions near the pump or generation wavelength limit the effectiveness of this materials, with their complicated microscopic origins remaining largely elusive. Most research on the absorption mechanism of ZnGeP2 focused on the defect effect, while the quasi-particle effect and exciton effect are significant as well. We herein carried out the ab initio studies of the electronic band structure and optical properties of ZnGeP2 crystal. The quasiparticle and excitonic effects were examined by comparing the results of PBE, GW approximation and Bethe–Salpeter equation. Quasiparticle effect was found to widen the quasi-direct band gap and increases the valence and conduction band dispersions, which mainly blue-shifts the imaginary part of the dielectric function. The increased band gap also leads to a broadened lineshape in the second order susceptibility. The excitonic effects significantly enhance the peak intensity in the long wave regime of the dielectric function and red-shift the peaks in the high energy regime, leading to the greatly improved agreement with experiment. Our results provided a microscopic guidance for improving ZnGeP2's optical performance. The semiconductor zinc germanium diphosphide (ZnGeP2) has wide applications in the infrared nonlinear optics (NLO) due to its high nonlinear optical coefficient, wide infrared transparency range and high thermal conductivity.![]()
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Affiliation(s)
- Hua Xie
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, School of Physical Sciences, University of Science and Technology of China Jinzhai Road 96 Hefei Anhui 230026 P. R. China +86-551-63607574
| | - Shenghao Fang
- Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou Fujian 350002 China
| | - He Zhao
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, School of Physical Sciences, University of Science and Technology of China Jinzhai Road 96 Hefei Anhui 230026 P. R. China +86-551-63607574
| | - Xiaoliang Xu
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, School of Physical Sciences, University of Science and Technology of China Jinzhai Road 96 Hefei Anhui 230026 P. R. China +86-551-63607574
| | - Ning Ye
- Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou Fujian 350002 China
| | - Wei Zhuang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou Fujian 350002 China
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17
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Excited States and Optical Properties of Hydrogen-Passivated Rectangular Graphenes: A Computational Study. Sci Rep 2019; 9:7958. [PMID: 31138848 PMCID: PMC6538642 DOI: 10.1038/s41598-019-44258-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 04/30/2019] [Indexed: 11/09/2022] Open
Abstract
In this paper, we perform large-scale electron-correlated calculations of optoelectronic properties of rectangular graphene-like polycyclic aromatic hydrocarbon molecules. Theoretical methodology employed in this work is based upon Pariser-Parr-Pople (PPP) π-electron model Hamiltonian, which includes long-range electron-electron interactions. Electron-correlation effects were incorporated using multi-reference singles-doubles configurationinteraction (MRSDCI) method, and the ground and excited state wave functions thus obtained were employed to calculate the linear optical absorption spectra of these molecules, within the electric-dipole approximation. As far as the ground state wave functions of these molecules are concerned, we find that with the increasing size, they develop a strong diradical open-shell character. Our results on optical absorption spectra are in very good agreement with the available experimental results, outlining the importance of electron-correlation effects in accurate description of the excited states. In addition to the optical gap, spin gap of each molecule was also computed using the same methodology. Calculated spin gaps exhibit a decreasing trend with the increasing sizes of the molecules, suggesting that the infinite graphene has a vanishing spin gap.
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18
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Saroka V, Pushkarchuk A, Kuten S, Portnoi M. Hidden correlation between absorption peaks in achiral carbon nanotubes and nanoribbons. JOURNAL OF SAUDI CHEMICAL SOCIETY 2018. [DOI: 10.1016/j.jscs.2018.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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19
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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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20
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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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21
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Senkovskiy BV, Usachov DY, Fedorov AV, Marangoni T, Haberer D, Tresca C, Profeta G, Caciuc V, Tsukamoto S, Atodiresei N, Ehlen N, Chen C, Avila J, Asensio MC, Varykhalov AY, Nefedov A, Wöll C, Kim TK, Hoesch M, Fischer FR, Grüneis A. Boron-Doped Graphene Nanoribbons: Electronic Structure and Raman Fingerprint. ACS NANO 2018; 12:7571-7582. [PMID: 30004663 DOI: 10.1021/acsnano.8b04125] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We investigate the electronic and vibrational properties of bottom-up synthesized aligned armchair graphene nanoribbons of N = 7 carbon atoms width periodically doped by substitutional boron atoms (B-7AGNRs). Using angle-resolved photoemission spectroscopy and density functional theory calculations, we find that the dopant-derived valence and conduction band states are notably hybridized with electronic states of Au substrate and spread in energy. The interaction with the substrate leaves the bands with pure carbon character rather unperturbed. This results in an identical effective mass of ≈0.2 m0 for the next-highest valence band compared with pristine 7AGNRs. We probe the phonons of B-7AGNRs by ultrahigh-vacuum (UHV) Raman spectroscopy and reveal the existence of characteristic splitting and red shifts in Raman modes due to the presence of substitutional boron atoms. Comparing the Raman spectra for three visible lasers (red, green, and blue), we find that interaction with gold suppresses the Raman signal from B-7AGNRs and the energy of the green laser (2.33 eV) is closer to the resonant E22 transition. The hybridized electronic structure of the B-7AGNR-Au interface is expected to improve electrical characteristics of contacts between graphene nanoribbon and Au. The Raman fingerprint allows the easy identification of B-7AGNRs, which is particularly useful for device fabrication.
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Affiliation(s)
- Boris V Senkovskiy
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77 , 50937 Köln , Germany
| | - Dmitry Yu Usachov
- St. Petersburg State University , 7/9 Universitetskaya nab. , Saint Petersburg 199034 , Russia
| | - Alexander V Fedorov
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77 , 50937 Köln , Germany
- St. Petersburg State University , 7/9 Universitetskaya nab. , Saint Petersburg 199034 , Russia
- IFW Dresden , P.O. Box 270116, D-01171 Dresden , Germany
| | - Tomas Marangoni
- Department of Chemistry , University of California , Tan Hall 680 , Berkeley , California 94720 , United States
| | - Danny Haberer
- Department of Chemistry , University of California , Tan Hall 680 , Berkeley , California 94720 , United States
| | - Cesare Tresca
- Department of Physical and Chemical Sciences and SPIN-CNR , University of L'Aquila , Via Vetoio 10 , I-67100 Coppito , Italy
- Institut des Nanosciences de Paris, Sorbonne Universités-UPMC univ Paris 6 and CNRS-UMR 7588 , 4 place Jussieu , F-75252 Paris , France
| | - Gianni Profeta
- Department of Physical and Chemical Sciences and SPIN-CNR , University of L'Aquila , Via Vetoio 10 , I-67100 Coppito , Italy
| | - Vasile Caciuc
- Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1) , Forschungszentrum Jülich and JARA , D-52425 Jülich , Germany
| | - Shigeru Tsukamoto
- Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1) , Forschungszentrum Jülich and JARA , D-52425 Jülich , Germany
| | - Nicolae Atodiresei
- Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1) , Forschungszentrum Jülich and JARA , D-52425 Jülich , Germany
| | - Niels Ehlen
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77 , 50937 Köln , Germany
| | - Chaoyu Chen
- ANTARES Beamline , Synchrotron SOLEIL & Universite Paris-Saclay, L' Orme des Merisiers , Saint Aubin-BP 48 , 91192 Gif sur Yvette Cedex , France
| | - José Avila
- ANTARES Beamline , Synchrotron SOLEIL & Universite Paris-Saclay, L' Orme des Merisiers , Saint Aubin-BP 48 , 91192 Gif sur Yvette Cedex , France
| | - Maria C Asensio
- ANTARES Beamline , Synchrotron SOLEIL & Universite Paris-Saclay, L' Orme des Merisiers , Saint Aubin-BP 48 , 91192 Gif sur Yvette Cedex , France
| | | | - Alexei Nefedov
- Institut für Funktionelle Grenzflächen (IFG), Karlsruher Institut für Technologie (KIT) , Hermann-von-Helmholtz-Platz 1 , 76344 Eggenstein-Leopoldshafen , Germany
| | - Christof Wöll
- Institut für Funktionelle Grenzflächen (IFG), Karlsruher Institut für Technologie (KIT) , Hermann-von-Helmholtz-Platz 1 , 76344 Eggenstein-Leopoldshafen , Germany
| | - Timur K Kim
- Diamond Light Source, Harwell Campus , Didcot , OX11 0DE , United Kingdom
| | - Moritz Hoesch
- Diamond Light Source, Harwell Campus , Didcot , OX11 0DE , United Kingdom
- DESY Photon Science, Deutsches Elektronen-Synchrotron , Notkestrasse 85 , 22607 Hamburg , Germany
| | - Felix R Fischer
- Department of Chemistry , University of California , Tan Hall 680 , Berkeley , California 94720 , United States
- Materials Science Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- Kavli Energy Nanosciences Institute at the University of California Berkeley and Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Alexander Grüneis
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77 , 50937 Köln , Germany
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22
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Zhang GQ, Kang N, Li JY, Lin L, Peng H, Liu Z, Xu HQ. Low-field magnetotransport in graphene cavity devices. NANOTECHNOLOGY 2018; 29:205707. [PMID: 29509145 DOI: 10.1088/1361-6528/aab478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Confinement and edge structures are known to play significant roles in the electronic and transport properties of two-dimensional materials. Here, we report on low-temperature magnetotransport measurements of lithographically patterned graphene cavity nanodevices. It is found that the evolution of the low-field magnetoconductance characteristics with varying carrier density exhibits different behaviors in graphene cavity and bulk graphene devices. In the graphene cavity devices, we observed that intravalley scattering becomes dominant as the Fermi level gets close to the Dirac point. We associate this enhanced intravalley scattering to the effect of charge inhomogeneities and edge disorder in the confined graphene nanostructures. We also observed that the dephasing rate of carriers in the cavity devices follows a parabolic temperature dependence, indicating that the direct Coulomb interaction scattering mechanism governs the dephasing at low temperatures. Our results demonstrate the importance of confinement in carrier transport in graphene nanostructure devices.
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Affiliation(s)
- G Q Zhang
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, Beijing 100871, People's Republic of China
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23
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Villegas CEP, Rodin AS, Carvalho A, Rocha AR. Two-dimensional exciton properties in monolayer semiconducting phosphorus allotropes. Phys Chem Chem Phys 2018; 18:27829-27836. [PMID: 27711643 DOI: 10.1039/c6cp05566d] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Excitons play a key role in technological applications since they have a strong influence on determining the efficiency of photovoltaic devices. Recently, it has been shown that the allotropes of phosphorus possess an optical band gap that can be tuned over a wide range of values including the near-infrared and visible spectra, which would make them promising candidates for optoelectronic applications. In this work we carry out ab initio many-body perturbation theory calculations to study the excitonic effects on the optical properties of two-dimensional phosphorus allotropes: the case of blue and black monolayers. We elucidate the most relevant optical transitions, exciton binding energy spectrum as well as real-space exciton distribution, particularly focusing on the absorption spectrum dependence on the incident light polarization. In addition, based on our results, we use a set of effective hydrogenic models, in which the electron-hole Coulomb interaction is included to estimate exciton binding energies and radii. Our results show an excellent agreement between the many-body methodology and the effective models.
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Affiliation(s)
- Cesar E P Villegas
- Istituto di Struttura della Materia of the National Research Council, Via Salaria Km 29.3, I-00016 Monterotondo Stazione, Italy and Instituto de Física Teórica, Universidade Estadual Paulista (UNESP), Rua Dr. Bento T. Ferraz, 271, São Paulo, SP 01140-070, Brazil.
| | - A S Rodin
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
| | - Alexandra Carvalho
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
| | - A R Rocha
- Instituto de Física Teórica, Universidade Estadual Paulista (UNESP), Rua Dr. Bento T. Ferraz, 271, São Paulo, SP 01140-070, Brazil.
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24
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Chong MC, Afshar-Imani N, Scheurer F, Cardoso C, Ferretti A, Prezzi D, Schull G. Bright Electroluminescence from Single Graphene Nanoribbon Junctions. NANO LETTERS 2018; 18:175-181. [PMID: 29215893 DOI: 10.1021/acs.nanolett.7b03797] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Thanks to their highly tunable band gaps, graphene nanoribbons (GNRs) with atomically precise edges are emerging as mechanically and chemically robust candidates for nanoscale light emitting devices of modulable emission color. While their optical properties have been addressed theoretically in depth, only few experimental studies exist, limited to ensemble measurements and without any attempt to integrate them in an electronic-like circuit. Here we report on the electroluminescence of individual GNRs suspended between the tip of a scanning tunneling microscope (STM) and a Au(111) substrate, constituting thus a realistic optoelectronic circuit. Emission spectra of such GNR junctions reveal a bright and narrow band emission of red light, whose energy can be tuned with the bias voltage applied to the junction, but always lying below the gap of infinite GNRs. Comparison with ab initio calculations indicates that the emission involves electronic states localized at the GNR termini. Our results shed light on unpredicted optical transitions in GNRs and provide a promising route for the realization of bright, robust, and controllable graphene-based light-emitting devices.
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Affiliation(s)
- Michael C Chong
- Université de Strasbourg , CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - Nasima Afshar-Imani
- Université de Strasbourg , CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - Fabrice Scheurer
- Université de Strasbourg , CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | | | | | - Deborah Prezzi
- CNR-Nanoscience Institute , S3 Center, 41125 Modena, Italy
| | - Guillaume Schull
- Université de Strasbourg , CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
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25
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Multiple Exciton Generation in Nanostructures for Advanced Photovoltaic Cells. JOURNAL OF NANOTECHNOLOGY 2018. [DOI: 10.1155/2018/7285483] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This paper reviews both experimental and theoretical work on nanostructures showing high quantum yields due to the phenomenon of multiple exciton generation. It outlines the aims and barriers to progress in identifying further such nanostructures and also includes important developments concerning solar devices where nanostructures act as the light-absorbing component. It reports on both semiconductor and carbon structures, both monocomposite (of various dimensionalities) and heterogeneous. Finally, it looks at future directions that can be taken to push solar cell efficiency above the classic limit set by Shockley and Queisser in 1961.
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26
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Abstract
One- and two-dimensional materials are being intensively investigated due to their interesting properties for next-generation optoelectronic devices. Among these, armchair-edged graphene nanoribbons are very promising candidates with optical properties that are dominated by excitons. In the presence of additional charges, trions (i.e., charged excitons) can occur in the optical spectrum. With our recently developed first-principle many-body approach (Phys. Rev. Lett. 116, 196804), we predict strongly bound trions in free-standing nanoribbons with large binding energies of 140-660 meV for widths of 14.6-3.6 Å. Both for the trions and for the excitons, we observe an almost linear dependency of their binding energies on the band gap. We observe several trion states with different character derived from the corresponding excitons. Because of the large bindings energies, this opens a route to applications by which optical properties are easily manipulated, for example, by electrical fields.
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Affiliation(s)
- Thorsten Deilmann
- Center for Atomic-Scale Materials Design (CAMD), Department of Physics, Technical University of Denmark , DK-2800 Kongens Lyngby, Denmark
| | - Michael Rohlfing
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster , 48149 Münster, Germany
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27
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Senkovskiy BV, Pfeiffer M, Alavi SK, Bliesener A, Zhu J, Michel S, Fedorov AV, German R, Hertel D, Haberer D, Petaccia L, Fischer FR, Meerholz K, van Loosdrecht PHM, Lindfors K, Grüneis A. Making Graphene Nanoribbons Photoluminescent. NANO LETTERS 2017; 17:4029-4037. [PMID: 28358214 DOI: 10.1021/acs.nanolett.7b00147] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We demonstrate the alignment-preserving transfer of parallel graphene nanoribbons (GNRs) onto insulating substrates. The photophysics of such samples is characterized by polarized Raman and photoluminescence (PL) spectroscopies. The Raman scattered light and the PL are polarized along the GNR axis. The Raman cross section as a function of excitation energy has distinct excitonic peaks associated with transitions between the one-dimensional parabolic subbands. We find that the PL of GNRs is intrinsically low but can be strongly enhanced by blue laser irradiation in ambient conditions or hydrogenation in ultrahigh vacuum. These functionalization routes cause the formation of sp3 defects in GNRs. We demonstrate the laser writing of luminescent patterns in GNR films for maskless lithography by the controlled generation of defects. Our findings set the stage for further exploration of the optical properties of GNRs on insulating substrates and in device geometries.
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Affiliation(s)
- B V Senkovskiy
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77, 50937 Köln, Germany
| | - M Pfeiffer
- Department für Chemie, Universität zu Köln , Luxemburger Strasse 116, 50939 Köln, Germany
| | - S K Alavi
- Department für Chemie, Universität zu Köln , Luxemburger Strasse 116, 50939 Köln, Germany
- Institut für Angewandte Physik der Universität Bonn , Wegeler Strasse 8, 53115 Bonn, Germany
| | - A Bliesener
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77, 50937 Köln, Germany
| | - J Zhu
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77, 50937 Köln, Germany
| | - S Michel
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77, 50937 Köln, Germany
| | - A V Fedorov
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77, 50937 Köln, Germany
- St. Petersburg State University , Ulianovskaya 1, St. Petersburg 198504, Russia
- IFW Dresden , P.O. Box 270116, Dresden D-01171, Germany
| | - R German
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77, 50937 Köln, Germany
| | - D Hertel
- Department für Chemie, Universität zu Köln , Luxemburger Strasse 116, 50939 Köln, Germany
| | - D Haberer
- Department of Chemistry, University of California at Berkeley , Tan Hall 680, Berkeley, California 94720, United States
| | - L Petaccia
- Elettra Sincrotrone Trieste , Strada Statale 14 km 163.5, 34149 Trieste, Italy
| | - F R Fischer
- Department of Chemistry, University of California at Berkeley , Tan Hall 680, Berkeley, California 94720, United States
| | - K Meerholz
- Department für Chemie, Universität zu Köln , Luxemburger Strasse 116, 50939 Köln, Germany
| | - P H M van Loosdrecht
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77, 50937 Köln, Germany
| | - K Lindfors
- Department für Chemie, Universität zu Köln , Luxemburger Strasse 116, 50939 Köln, Germany
| | - A Grüneis
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77, 50937 Köln, Germany
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Tsuneda T, Singh RK, Nakata A. On low-lying excited states of extended nanographenes. J Comput Chem 2017; 38:2020-2029. [DOI: 10.1002/jcc.24846] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 03/08/2017] [Accepted: 03/21/2017] [Indexed: 01/15/2023]
Affiliation(s)
- Takao Tsuneda
- Fuel Cell Nanomaterials Center, University of Yamanashi; Kofu 400-0021 Japan
| | - Raman K. Singh
- Fuel Cell Nanomaterials Center, University of Yamanashi; Kofu 400-0021 Japan
| | - Ayako Nakata
- First-principles Simulation Group; Nano-Theory Field, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS); Tsukuba 305-0044 Japan
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29
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Lin YT, Lin SY, Chiu YH, Lin MF. Alkali-created rich properties in grapheme nanoribbons: Chemical bondings. Sci Rep 2017; 7:1722. [PMID: 28496144 PMCID: PMC5431839 DOI: 10.1038/s41598-017-01688-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/21/2017] [Indexed: 11/28/2022] Open
Abstract
The alkali-adsorbed graphene nanoribbons exhibit the feature-rich electronic and magnetic properties. From the first-principles calculations, there are only few adatom-dominated conduction bands, and the other conduction and valence bands are caused by carbon atoms. A lot of free electrons are revealed in the occupied alkali- and carbon-dependent conduction bands. Energy bands are sensitive to the concentration, distribution and kind of adatom and the edge structure, while the total linear free carrier density only relies on the first one. These mainly arise from a single s − 2pz orbital hybridization in the adatom-carbon bond. Specifically, zigzag systems can present the anti-ferromagnetic ordering across two edges, ferromagnetic ordering along one edge and non-magnetism, being reflected in the edge-localized energy bands with or without spin splitting. The diverse energy dispersions contribute many special peaks in density of states. The critical chemical bonding and the distinct spin configuration could be verified from the experimental measurements.
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Affiliation(s)
- Yu-Tsung Lin
- Department of Physics, National Cheng Kung University, Tainan, 701, Taiwan
| | - Shih-Yang Lin
- Department of Physics, National Cheng Kung University, Tainan, 701, Taiwan.
| | - Yu-Huang Chiu
- Department of Applied Physics, National Pingtung University, Pingtung, 900, Taiwan
| | - Ming-Fa Lin
- Department of Physics, National Cheng Kung University, Tainan, 701, Taiwan.
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30
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Tandel RD, Naik RS, Seetharamappa J. Electrochemical Characteristics and Electrosensing of an Antiviral Drug, Entecavir via Synergic Effect of Graphene Oxide Nanoribbons and Ceria Nanorods. ELECTROANAL 2017. [DOI: 10.1002/elan.201600492] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Roopa S. Naik
- Department of Chemistry; Karnatak University; Dharwad 580 003 India
| | - J. Seetharamappa
- Department of Chemistry; Karnatak University; Dharwad 580 003 India
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31
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Xu Q, Ma T, Danesh M, Shivananju BN, Gan S, Song J, Qiu CW, Cheng HM, Ren W, Bao Q. Effects of edge on graphene plasmons as revealed by infrared nanoimaging. LIGHT, SCIENCE & APPLICATIONS 2017; 6:e16204. [PMID: 30167226 PMCID: PMC6062181 DOI: 10.1038/lsa.2016.204] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 07/01/2016] [Accepted: 08/14/2016] [Indexed: 05/13/2023]
Abstract
We used scattering-type scanning near-field optical microscopy (s-SNOM) to investigate the plasmonic properties of edges in well-defined graphene nanostructures, including sharp tapers, nanoribbons and nanogaps, which were all fabricated via the growth-etching chemical vapor deposition (GECVD) method. The obtained near-field images revealed the localized plasmon modes along the graphene nanoribbon; these modes strongly depended on the size of the graphene pattern, the angle of the tapered graphene and the infrared excitation wavelength. These interesting plasmon modes were verified by numerical simulations and explained by the reflection, and interference of electromagnetic waves at the graphene-SiO2 edge. The constructive interference at the graphene nanogap caused by charge accumulation was demonstrated for the first time. Using the infrared nanoimaging technique, greater plasmon broadening was observed in the zigzag edge than in the armchair edge. Our study suggests that graphene edges should be separated by an effective working distance to avoid the overlapping of localized plasmon modes, which is very important for the design of graphene-based plasmonic circuits and devices.
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Affiliation(s)
- Qingyang Xu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren-ai Road, Suzhou 215123, Jiangsu, China
| | - Teng Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China
| | - Mohammad Danesh
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore
| | - Bannur Nanjunda Shivananju
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren-ai Road, Suzhou 215123, Jiangsu, China
| | - Sheng Gan
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren-ai Road, Suzhou 215123, Jiangsu, China
| | - Jingchao Song
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore
| | - Hui-Ming Cheng
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China
| | - Wencai Ren
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China
| | - Qiaoliang Bao
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren-ai Road, Suzhou 215123, Jiangsu, China
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia
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32
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Lou P. Quasiparticle energies, exciton level structures and optical absorption spectra of ultra-narrow ZSiCNRs. RSC Adv 2017. [DOI: 10.1039/c7ra09993b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
GW quasiparticle energies, exciton structures and optical absorption spectra of ultra-narrow N-ZSiCNRs.
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Affiliation(s)
- Ping Lou
- Department of Physics
- Anhui University
- Hefei 230039
- China
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33
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Espinosa-García WF, Osorio-Guillén JM, Araujo CM. Dimension-dependent band alignment and excitonic effects in graphitic carbon nitride: a many-body perturbation and time-dependent density functional theory study. RSC Adv 2017. [DOI: 10.1039/c7ra07134e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
First-principles many-body theory and time-dependent density functional theory were used to study the dimension effects on the band alignment and optical properties of s-triazine and graphitic C3N4.
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Affiliation(s)
- W. F. Espinosa-García
- Universidad de San Buenaventura-Medellín
- Facultad de Ingenierías
- Grupo de Investigación en Modelamiento y Simulación Computacional
- Medellín
- Colombia
| | | | - C. Moyses Araujo
- Materials Theory Division
- Department of Physics and Astronomy
- Uppsala University
- Uppsala
- Sweden
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34
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Shekhirev M, Vo TH, Kunkel DA, Lipatov A, Enders A, Sinitskii A. Aggregation of atomically precise graphene nanoribbons. RSC Adv 2017. [DOI: 10.1039/c7ra08049b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Atomically precise chevron graphene nanoribbons can form bulk π–π stacked aggregates as well as few-μm-long one-dimensional structures on surfaces that could be used for electronic device fabrication.
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Affiliation(s)
| | - Timothy H. Vo
- Department of Chemistry
- University of Nebraska – Lincoln
- Lincoln
- USA
| | - Donna A. Kunkel
- Department of Physics and Astronomy
- University of Nebraska – Lincoln
- Lincoln
- USA
| | - Alexey Lipatov
- Department of Chemistry
- University of Nebraska – Lincoln
- Lincoln
- USA
| | - Axel Enders
- Department of Physics and Astronomy
- University of Nebraska – Lincoln
- Lincoln
- USA
- Nebraska Center for Materials and Nanoscience
| | - Alexander Sinitskii
- Department of Chemistry
- University of Nebraska – Lincoln
- Lincoln
- USA
- Nebraska Center for Materials and Nanoscience
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35
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Mansilla Wettstein C, Bonafé FP, Oviedo MB, Sánchez CG. Optical properties of graphene nanoflakes: Shape matters. J Chem Phys 2016; 144:224305. [DOI: 10.1063/1.4953172] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Candela Mansilla Wettstein
- Instituto de Investigaciones Fisicoquímicas de Córdoba, Consejo Nacional de Investigaciones Científicas y Técnicas (INFIQC - CONICET), Departamento de Matemática y Física, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba X5000HUA, Argentina
| | - Franco P. Bonafé
- Instituto de Investigaciones Fisicoquímicas de Córdoba, Consejo Nacional de Investigaciones Científicas y Técnicas (INFIQC - CONICET), Departamento de Matemática y Física, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba X5000HUA, Argentina
| | - M. Belén Oviedo
- Department of Chemical & Environmental Engineering and Materials Science and Engineering Program, University of California, Riverside, California 92521, USA
| | - Cristián G. Sánchez
- Instituto de Investigaciones Fisicoquímicas de Córdoba, Consejo Nacional de Investigaciones Científicas y Técnicas (INFIQC - CONICET), Departamento de Matemática y Física, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba X5000HUA, Argentina
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36
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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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37
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Lu DB, Luo CG, Song YL, Pan QN, Pu CY. Electronic and Optical Properties of O-Terminated Armchair Graphene Nanoribbons. CHINESE J CHEM PHYS 2016. [DOI: 10.1063/1674-0068/29/cjcp1506125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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38
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Soavi G, Dal Conte S, Manzoni C, Viola D, Narita A, Hu Y, Feng X, Hohenester U, Molinari E, Prezzi D, Müllen K, Cerullo G. Exciton-exciton annihilation and biexciton stimulated emission in graphene nanoribbons. Nat Commun 2016; 7:11010. [PMID: 26984281 PMCID: PMC4800436 DOI: 10.1038/ncomms11010] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 02/10/2016] [Indexed: 01/21/2023] Open
Abstract
Graphene nanoribbons display extraordinary optical properties due to one-dimensional quantum-confinement, such as width-dependent bandgap and strong electron–hole interactions, responsible for the formation of excitons with extremely high binding energies. Here we use femtosecond transient absorption spectroscopy to explore the ultrafast optical properties of ultranarrow, structurally well-defined graphene nanoribbons as a function of the excitation fluence, and the impact of enhanced Coulomb interaction on their excited states dynamics. We show that in the high-excitation regime biexcitons are formed by nonlinear exciton–exciton annihilation, and that they radiatively recombine via stimulated emission. We obtain a biexciton binding energy of ≈250 meV, in very good agreement with theoretical results from quantum Monte Carlo simulations. These observations pave the way for the application of graphene nanoribbons in photonics and optoelectronics. Graphene nanoribbons confine electrons to just one dimension and this gives rise to strong electron–hole interactions. Here, the authors investigate the creation and recombination of biexcitons in these structures by ultrafast optical pulses using femtosecond transient absorption spectroscopy.
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Affiliation(s)
- Giancarlo Soavi
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo Da Vinci 32, Milano 20133, Italy
| | - Stefano Dal Conte
- Istituto di Fotonica e Nanotecnologie, CNR, Piazza Leonardo Da Vinci 32, Milano 20133, Italy
| | - Cristian Manzoni
- Istituto di Fotonica e Nanotecnologie, CNR, Piazza Leonardo Da Vinci 32, Milano 20133, Italy
| | - Daniele Viola
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo Da Vinci 32, Milano 20133, Italy
| | - Akimitsu Narita
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Yunbin Hu
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Xinliang Feng
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Ulrich Hohenester
- Institute of Physics, University of Graz, Universitätsplatz 5, Graz 8010, Austria
| | - Elisa Molinari
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia, Modena 41125, Italy.,Istituto Nanoscienze, CNR, via G. Campi 213/a, Modena 41125, Italy
| | - Deborah Prezzi
- Istituto Nanoscienze, CNR, via G. Campi 213/a, Modena 41125, Italy
| | - Klaus Müllen
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Giulio Cerullo
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo Da Vinci 32, Milano 20133, Italy.,Istituto di Fotonica e Nanotecnologie, CNR, Piazza Leonardo Da Vinci 32, Milano 20133, Italy
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39
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Sahin H, Torun E, Bacaksiz C, Horzum S, Kang J, Senger RT, Peeters FM. Computing optical properties of ultra-thin crystals. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2016. [DOI: 10.1002/wcms.1252] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- H. Sahin
- Department of Physics; University of Antwerp; Antwerp Belgium
| | - E. Torun
- Department of Physics; University of Antwerp; Antwerp Belgium
| | - C. Bacaksiz
- Department of Physics; Izmir Institute of Technology; Izmir Turkey
| | - S. Horzum
- Department of Physics; University of Antwerp; Antwerp Belgium
- Department of Engineering Physics; Faculty of Engineering, Ankara University; Ankara Turkey
| | - J. Kang
- Department of Physics; University of Antwerp; Antwerp Belgium
| | - R. T. Senger
- Department of Physics; Izmir Institute of Technology; Izmir Turkey
| | - F. M. Peeters
- Department of Physics; University of Antwerp; Antwerp Belgium
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40
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Lüder J, Puglia C, Ottosson H, Eriksson O, Sanyal B, Brena B. Many-body effects and excitonic features in 2D biphenylene carbon. J Chem Phys 2016; 144:024702. [DOI: 10.1063/1.4939273] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- Johann Lüder
- Department of Physics and Astronomy, Uppsala University, P.O. Box 516, 751 20 Uppsala, Sweden
| | - Carla Puglia
- Department of Physics and Astronomy, Uppsala University, P.O. Box 516, 751 20 Uppsala, Sweden
| | - Henrik Ottosson
- Department of Chemistry–BMC, Uppsala University, P.O. Box 576, 751 23 Uppsala, Sweden
| | - Olle Eriksson
- Department of Physics and Astronomy, Uppsala University, P.O. Box 516, 751 20 Uppsala, Sweden
| | - Biplab Sanyal
- Department of Physics and Astronomy, Uppsala University, P.O. Box 516, 751 20 Uppsala, Sweden
| | - Barbara Brena
- Department of Physics and Astronomy, Uppsala University, P.O. Box 516, 751 20 Uppsala, Sweden
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41
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Maslov VG, Svitenkov AI, Krzhizhanovskaya VV. Abnormally high oscillator strengths of the graphene nanoribbons electronic spectrum: quantum chemistry calculations. RSC Adv 2016. [DOI: 10.1039/c6ra04528f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Armchair-edged narrow graphene nanoribbons (GNRs) are modelled by semi-empirical Hartree–Fock based quantum chemistry method ZINDO/S-CI. Abnormally high oscillator strengths of over 200 are found in long GNRs (length > 150 hexagonal carbon rings).
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42
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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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43
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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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Chiappe G, Louis E, San-Fabián E, Vergés JA. Can model Hamiltonians describe the electron-electron interaction in π-conjugated systems? PAH and graphene. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:463001. [PMID: 26501495 DOI: 10.1088/0953-8984/27/46/463001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Model Hamiltonians have been, and still are, a valuable tool for investigating the electronic structure of systems for which mean field theories work poorly. This review will concentrate on the application of Pariser-Parr-Pople (PPP) and Hubbard Hamiltonians to investigate some relevant properties of polycyclic aromatic hydrocarbons (PAH) and graphene. When presenting these two Hamiltonians we will resort to second quantisation which, although not the way chosen in its original proposal of the former, is much clearer. We will not attempt to be comprehensive, but rather our objective will be to try to provide the reader with information on what kinds of problems they will encounter and what tools they will need to solve them. One of the key issues concerning model Hamiltonians that will be treated in detail is the choice of model parameters. Although model Hamiltonians reduce the complexity of the original Hamiltonian, they cannot be solved in most cases exactly. So, we shall first consider the Hartree-Fock approximation, still the only tool for handling large systems, besides density functional theory (DFT) approaches. We proceed by discussing to what extent one may exactly solve model Hamiltonians and the Lanczos approach. We shall describe the configuration interaction (CI) method, a common technology in quantum chemistry but one rarely used to solve model Hamiltonians. In particular, we propose a variant of the Lanczos method, inspired by CI, that has the novelty of using as the seed of the Lanczos process a mean field (Hartree-Fock) determinant (the method will be named LCI). Two questions of interest related to model Hamiltonians will be discussed: (i) when including long-range interactions, how crucial is including in the Hamiltonian the electronic charge that compensates ion charges? (ii) Is it possible to reduce a Hamiltonian incorporating Coulomb interactions (PPP) to an 'effective' Hamiltonian including only on-site interactions (Hubbard)? The performance of CI will be checked on small molecules. The electronic structure of azulene and fused azulene will be used to illustrate several aspects of the method. As regards graphene, several questions will be considered: (i) paramagnetic versus antiferromagnetic solutions, (ii) forbidden gap versus dot size, (iii) graphene nano-ribbons, and (iv) optical properties.
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Affiliation(s)
- G Chiappe
- Unidad Asociada del CSIC and Instituto Universitario de Materiales, Universidad de Alicante, San Vicente del Raspeig, 03690 Alicante, Spain. Departamento de Física Aplicada, Universidad de Alicante, San Vicente del Raspeig, 03690 Alicante, Spain
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Yadav P, Srivastava PK, Ghosh S. Dielectric screening of excitons in monolayer graphene. NANOSCALE 2015; 7:18015-18019. [PMID: 26469682 DOI: 10.1039/c5nr04800a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Excitonic transitions in graphene monolayers embedded in different dielectric environments have been investigated using combined absorption and transmission spectroscopy techniques. To vary the dielectric environment, graphene monolayer has been exfoliated in liquid medium. It has been shown that exciton binding energy decreases with increase in the dielectric constant of exfoliating solvents due to the screening of electron-electron and electron-hole interactions in graphene. The typical line shape of the excitonic peak in the absorption spectra is explained by the Fano resonance between the excitonic state and band continuum. Further it has been shown that, there exists a scaling relationship between the dielectric constant of the liquid and the exciton binding energy.
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Affiliation(s)
- Premlata Yadav
- Electronic Materials and Device Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067, India.
| | - Pawan Kumar Srivastava
- Electronic Materials and Device Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067, India.
| | - Subhasis Ghosh
- Electronic Materials and Device Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067, India.
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Li Y, Chen W, Ren H, Zhou X, Li H. Multiple helical configuration and quantity threshold of graphene nanoribbons inside a single-walled carbon nanotube. Sci Rep 2015; 5:13741. [PMID: 26374276 PMCID: PMC4570994 DOI: 10.1038/srep13741] [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: 06/03/2015] [Accepted: 08/04/2015] [Indexed: 11/09/2022] Open
Abstract
Molecular dynamics simulation has been carried out to explore the configuration and quantity threshold of multiple graphene nanoribbons (GNRs) in single-walled carbon nanotube (SWCNT). The simulation results showed that several GNRs tangled together to form a perfect spiral structure to maximize the π-π stacking area when filling inside SWCNT. The formation of multiple helical configuration is influenced by the combined effect of structure stability, initial arrangement and tube space, meanwhile its forming time is related to helical angle. The simulated threshold of GNRs in SWCNT decreases with GNR width but increases with SWCNT diameter, and two formulas have come up in this study to estimate the quantity threshold for GNRs. It has been found that multilayered graphite is hard to be stripped in SWCNT because the special helical configuration with incompletely separated GNRs is metastable. This work provides a possibility to control the configuration of GNR@SWCNT.
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Affiliation(s)
- Yifan Li
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, People's Republic of China
| | - Wei Chen
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, People's Republic of China
| | - Hongru Ren
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, People's Republic of China
| | - Xuyan Zhou
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, People's Republic of China
| | - Hui Li
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, People's Republic of China
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Shu H, Li Y, Wang S, Wang J. Quasi-particle energies and optical excitations of hydrogenated and fluorinated germanene. Phys Chem Chem Phys 2015; 17:4542-50. [PMID: 25583554 DOI: 10.1039/c4cp05146g] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using density functional theory, the G0W0 method and Bethe-Salpeter equation calculations, we systematically explore the structural, electronic and optical properties of hydrogenated and fluorinated germanene. The hydrogenated/fluorinated germanene tends to form chair and zigzag-line configurations and its electronic and optical properties show close geometry dependence. The chair hydrogenated/fluorinated and zigzag-line fluorinated germanene are direct band-gap semiconductors, while the zigzag-line hydrogenated germanene owns an indirect band-gap. Moreover, the quasi-particle corrections are significant and strong excitonic effects with large exciton binding energies are observed. Moreover, the zigzag-line hydrogenated/fluorinated germanene shows highly anisotropic optical responses, which may be used as a good optical linear polarizer.
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Affiliation(s)
- Huabing Shu
- Department of Physics, Southeast University, Nanjing, 211189, China.
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Vo TH, Shekhirev M, Lipatov A, Korlacki RA, Sinitskii A. Bulk properties of solution-synthesized chevron-like graphene nanoribbons. Faraday Discuss 2015; 173:105-13. [PMID: 25465679 DOI: 10.1039/c4fd00131a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Graphene nanoribbons (GNRs) have received a great deal of attention due to their promise for electronic and optoelectronic applications. Several recent studies have focused on the synthesis of GNRs by the bottom-up approaches that could yield very narrow GNRs with atomically precise edges. One type of GNRs that has received a considerable attention is the chevron-like GNR with a very distinct periodic structure. Surface-assisted and solution-based synthetic approaches for the chevron-like GNRs have been developed, but their electronic properties have not been reported yet. In this work, we synthesized chevron-like GNRs in bulk by a solution-based method, characterized them by a number of spectroscopic techniques and measured their bulk conductivity. We demonstrate that solution-synthesized chevron-like GNRs are electrically conductive in bulk, which makes them a potentially promising material for applications in organic electronics and photovoltaics.
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Affiliation(s)
- Timothy H Vo
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, USA.
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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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Lee MW, Kim J, Suh JS. Characteristics of graphene quantum dots determined by edge structures: three kinds of dots fabricated using thermal plasma jet. RSC Adv 2015. [DOI: 10.1039/c5ra12223f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Model structures of the three types of graphene quantum dots; armchair (red), zigzag (blue), and hybrid (yellow) GQDs.
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Affiliation(s)
- Myung Woo Lee
- Laboratory, Department of Chemistry
- Seoul National University
- Seoul 151-747
- Republic of Korea
| | - Juhan Kim
- Laboratory, Department of Chemistry
- Seoul National University
- Seoul 151-747
- Republic of Korea
| | - Jung Sang Suh
- Laboratory, Department of Chemistry
- Seoul National University
- Seoul 151-747
- Republic of Korea
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