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Energy & Environmental Materials 2024年第4期7卷 285-294页

作者： Yan Zhang Huandi Zhang Xiaoxiao Wang Xiaowei Shi Zehua Zhao Yaling Wang Jiamei Liu Cheng Tang Guolong Wang Lei Li State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and Engineering Xi'an Jiaotong University Center for Materials Chemistry Frontier Institute of Science and TechnologyXi'an Jiaotong University Instrument Analysis Center of Xi'an Jiaotong University Xi'an Jiaotong University

The electrochemical performance of microsupercapacitors with graphene electrodes is reduced by the issue of graphene sheets aggregation,which limits electrolyte ions penetration into *** the space between graphene sheets in electrodes facilitates the electrolyte ions penetration,but sacrifices its electronic conductivity which also influences the charge storage ability.

关键词： areal energy density graphene graphene nanoribbons microsupercapacitors structure engineering

Sandwich structured graphene-wrapped FeS-graphene nanoribbons with improved cycling stability for lithium ion batteries

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Nano Research 2016年第10期9卷 2904-2911页

作者： Lei Li Caitian Gao Anton Kovalchuk Zhiwei Peng Gedeng Ruan Yang Yang Huilong Fei Qifeng Zhong Yilun Li James M. Tour Department of Chemistry Rice University 5100 Main Street Houston Texas 77005 USA School of Physical Science and Technology Lanzhou University Lanzhou 730000 China NanoCarbon Center Rice University 6100 Main Street Houston Texas 77005 USA State Key Laboratory of Bioelectronics School of Biological Science and Medical Engineering Southeast University Nanjing 210096 China Department of Materials Science and NanoEngineering Rice University 6100 Main Street Houston Texas 77005 USA

Sandwich structured graphene-wrapped FeS-graphene nanoribbons （G@FeS-GNIKs） were developed. In this composite, FeS nanoparticles were sandwiched between graphene and graphene nanoribbons. When used as anodes in lithium ion batteries （L1Bs）, the G@FeS-GNR composite demonstrated an outstanding electrochemical performance. This composite showed high reversible capacity, good rate performance, and enhanced cycling stability owing to the synergy between the electrically conductive graphene, graphene nanoribbons, and FeS. The design concept developed here opens up a new avenue for constructing anodes with improved electrochemical stability for LIBs.

关键词： lithium ion battery iron sulfide graphene nanoribbons graphene energy storage

Modulating magnetism of nitrogen-doped zigzag graphene nanoribbons

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Chinese Physics B 2014年第6期23卷 507-513页

作者：赵尚骞吕燕吕文刚梁文杰王恩哥 Institute of Physics Chinese Academy of Sciences and Beijing National Laboratory for Condensed Matter Physics International Center for Quantum Materials School of Physics Peking University

We present a study of electronic properties of zigzag graphene nanoribbons （ZGNRs） substitutionally doped with nitrogen atoms at a single edge by first principle calculations. We find that the two edge states near the Fermi level sepa- rate due to the asymmetric nitrogen-doping. The ground states of these systems become ferromagnetic because the local magnetic moments along the undoped edges remain and those along the doped edges are suppressed. By controlling the charge-doping level, the magnetic moments of the whole ribbons are modulated. Proper charge doping leads to interest- ing half-metallic and single-edge conducting ribbons which would be helpful for designing graphene-nanoribbon-based spintronic devices in the future.

关键词： graphene nanoribbons charge doping spin-polarization spatial localization

First principle study of edge topological defect-modulated electronic and magnetic properties in zigzag graphene nanoribbons

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Chinese Physics B 2017年第10期26卷 169-174页

作者：黄露婷陈铮王永欣卢艳丽 State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical University

Zigzag graphene nanoribbon （ZGNR） is a promising candidate for next-generation spintronic devices. Development of the field requires potential systems with variable and adjustable electromagnetic properties. Here we show a detailed investigation of ZGNR decorated with edge topological defects （ED-ZGNR） synthesized in laboratory by Ruffieux in 2015 [Pascal Ruffieux, Shiyong Wang, Bo Yang, et al. 2015 Nature 531 489]. The pristine ED-ZGNR in the ground state is an antiferromagnetic semiconductor, and the acquired band structure is significantly changed compared with that of perfect ZGNR. After doping heteroatoms on the edge, the breaking of degeneration of band structure makes the doped ribbon a half-semi-metal, and nonzero magnetic moments are induced. Our results indicate the tunable electronic and magnetic properties of ZGNR by deriving unique edge state from topological defect, which opens a new route to practical nano devices based on ZGNR.

关键词： graphene nanoribbons topological defect spin edge

Chevron-type graphene nanoribbons with a reduced energy band gap:Solution synthesis,scanning tunneling microscopy and electrical characterization

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Nano Research 2020年第6期13卷 1713-1722页

作者： Ximeng Liu Gang Li Alexey Lipatov Tao Sun Mohammad Mehdi Pour Narayana R.Aluru Joseph W.Lyding Alexander Sinitskii Beckman Institute for Advanced Science and Technology University of Illinois at Urbana-ChampaignUrbanaIL61801USA Department of Electrical and Computer Engineering University of Illinois at Urbana-ChampaignUrbanaIL61801USA Department of Chemistry University of Nebraska-LincolnLincolnNE68588USA Department of Mechanical Science and Engineering University of Illinois at Urbana-ChampaignUrbanaIL61801USA Nebraska Center for Materials and Nanoscience University of Nebraska-LincolnLincolnNE68588USA

graphene nanoribbons(GNRs)attract a growing interest due to their tunable physical properties and promise for device applications.A variety of atomically precise GNRs have recently been synthesized by on-surface and solution *** on-surface GNRs can be conveniently visualized by scanning tunneling microscopy(STM),and their electronic structure can be probed by scanning tunneling spectroscopy(STS),such characterization remains a great challenge for the solution-synthesized ***,we report solution synthesis and detailed STM/STS characterization of atomically precise GNRs with a meandering shape that are structurally related to chevron GNRs but have a reduced energy band *** ribbons were synthesized by Ni0-mediated Yamamoto polymerization of specially designed molecular precursors using triflates as the leaving groups and oxidative cyclodehydrogenation of the resulting polymers using Scholl *** ribbons were deposited onto III-V semiconducting InAs(110)substrates by a dry contact transfer ***-resolution STM/STS characterization not only confirmed the GNR geometry,but also revealed details of electronic structure including energy states,electronic band gap,as well as the spatial distribution of the local density of *** experimental STS band gap of GNRs is about 2 eV,which is very close to 2.35 eV predicted by the density functional theory simulations with GW correction,indicating a weak screening effect of InAs(110)***,several aspects of GNR-InAs(110)substrate interactions were also probed and analyzed,including GNR tunable transparency,alignment to the substrate,and manipulations of GNR position by the STM *** weak interaction between the GNRs and the InAs(110)surface makes InAs(110)an ideal substrate for investigating the intrinsic properties of *** of the reduced energy band gap of these ribbons,the GNR thin films exhibit appreciably high electrical conductivity and on/off ratios of about 1

关键词： graphene nanoribbons bottom-up synthesis electronic structure dry contact transfer scanning tunneling microscopy scanning tunneling spectroscopy

Effects of Monovacancy on Thermal Properties of Bilayer graphene nanoribbons by Molecular Dynamics Simulations

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Journal of Thermal Science 2021年第6期30卷 1917-1924页

作者： YANG Ming ZHANG Xingli ZHANG Hang Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China College of Mechanical and Electrical Engineering Northeast Forestry UniversityHarbin 150040China Department of Mechanical Engineering University of ColoradoBoulderCO80309USA

The monovacancy defect effect on thermal conductivity of bilayer graphene nanoribbons(BGNs)was investigated using non-equilibrium molecular dynamics(NEMD)simulations in this *** results demonstrate that the presence of monovacancy defect in BGNs reduces their thermal transport properties *** major finding of this work shows that the calculated thermal conductivity reduces approximately linearly with the raise of monovacancy *** contrast to the temperature-dependent thermal conductivity in perfect BGNs,the thermal conductivity of defected BGNs first increases and then decreases with the increasing *** addition,when the difference in the monovacancy density between two layers is larger,the thermal conductivity of BGNs is *** also calculated the phonon density of states,phonon relaxation time and participation ratio to provide a deeper understanding of the simulation *** investigation confirms that the BGNs-based nano-devices could be applied in thermal management by defect engineering.

关键词： monovacancy thermal conductivity molecular dynamics graphene nanoribbons

Effect of electron injection in copper-contacted graphene nanoribbons

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Nano Research 2016年第9期9卷 2735-2746页

作者： Konstantin A.Simonov Nikolay A.Vinogradov Alexander S.Vinogradov Alexander V.Generalov Gleb I.Svirskiy Attilio A.Cafolla Nils Martensson Alexei B. Preobrajenski Department of Physics and Astronomy Uppsala UniversityUppsala Box 51675120Sweden MAX Ⅳ Laboratory Lund UniversityLund Box 11822100Sweden V.A.Fock Institute of Physics St.Petersburg State UniversitySt.Petersburg 198504Russia School of Physical Sciences Dublin City UniversityDublin 9Ireland

For practical electronic device applications of graphene nanoribbons (GNRs), it is essential to have abrupt and well-defined contacts between the ribbon and the adjacent metal lead. By analogy with graphene, these contacts can induce electron or hole doping, which may significantly affect the I/V characteristics of the device. Cu is among the most popular metals of choice for contact materials. In this study, we investigate the effect of in situ intercalation of Cu on the electronic structure of atomically precise, spatially aligned armchair GNRs of width N = 7 (7-AGNRs) fabricated via a bottom-up method on the Au(788) surface. Scanning tunneling microscopy data reveal that the complete intercalation of about one monolayer of Cu under 7-AGNRs can be facilitated by gentle annealing of the sample at 80 °C. Angle-resolved photoemission spectroscopy (ARPES) data clearly reflect the one-dimensional character of the 7-AGNR band dispersion before and after intercalation. Moreover, ARPES and core-level photoemission results show that intercalation of Cu leads to significant electron injection into the nanoribbons, which causes a pronounced downshift of the valence and conduction bands of the GNR with respect to the Fermi energy (ΔE ~ 0.5 eV). As demonstrated by ARPES and X-ray absorption spectroscopy measurements, the effect of Cu intercalation is restricted to n-doping only, without considerable modification of the band structure of the GNRs. Post-annealing of the 7-AGNRs/Cu/Au(788) system at 200 °C activates the diffusion of Cu into Au and the formation of a Cu-rich surface Au layer. Alloying of intercalated Cu leads to the recovery of the initial position of GNR-related bands with respect to the Fermi energy (E F), thus, proving the tunability of the induced n-doping.

关键词： graphene nanoribbons bottom-up method copper intercalation charge injection angle-resolved photoemission spectroscopy (ARPES) scanning tunneling microscopy

On-surface activation of benzylic C-H bonds for the synthesis of pentagon-fused graphene nanoribbons

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Nano Research 2021年第12期14卷 4754-4759页

作者： Xiushang Xu Marco Di Giovannantonio José I.Urgel Carlo A.Pignedoli Pascal Ruffieux Klaus Müllen Roman Fasel Akimitsu Narita Present address:Istituto di Struttura della Materia-CNR(ISM-CNR) via Fosso del Cavaliere 10000133RomaItaly Present address:IMDEA Nanoscience C/Faraday 9Campus de Cantoblanco28049MadridSpain Max Planck Institute for Polymer Research 55128MainzGermany Empa Swiss Federal Laboratories for Materials Science and Technologynanotech@surfaces Laboratory8600DübendorfSwitzerland Organic and Carbon Nanomaterials Unit Okinawa Institute of Science and Technology Graduate University1919-1 TanchaOnna-sonKunigami-gunOkinawa904-0495Japan Institute of Physical Chemistry Johannes Gutenberg University MainzDuesbergweg 10-1455128MainzGermany

graphene nanoribbons (GNRs) have potential for applications in electronic devices. A key issue, thereby, is the fine-tuning of their electronic characteristics, which can be achieved through subtle structural modifications. These are not limited to the conventional armchair, zigzag, and cove edges, but also possible through incorporation of non-hexagonal rings. On-surface synthesis enables the fabrication and visualization of GNRs with atomically precise chemical structures, but strategies for the incorporation of non-hexagonal rings have been underexplored. Herein, we describe the on-surface synthesis of armchair-edged GNRs with incorporated five-membered rings through the C-H activation and cyclization of benzylic methyl groups. Ortho-Tolyl-substituted dibromobianthryl was employed as the precursor monomer, and visualization of the resulting structures after annealing at 300 °C on a gold surface by high-resolution noncontact atomic force microscopy clearly revealed the formation of methylene-bridged pentagons at the GNR edges. These persisted after annealing at 340 °C, along with a few fully conjugated pentagons having singly-hydrogenated apexes. The benzylic methyl groups could also migrate or cleave-off, resulting in defects lacking the five-membered rings. Moreover, unexpected and unique structural rearrangements, including the formation of embedded heptagons, were observed. Despite the coexistence of different reaction pathways that hamper selective synthesis of a uniform structure, our results provide novel insights into on-surface reactions en route to functional, non-benzenoid carbon nanomaterials.

关键词： graphene nanoribbons on-surface synthesis scanning-tunneling microscope noncontact atomic force microscope C-H activation

Oxygen-promoted synthesis of armchair graphene nanoribbons on Cu(111)

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Science China Chemistry 2021年第4期64卷 636-641页

作者： Penghui Ji Oliver MacLean Gianluca Galeotti Dominik Dettmann Giulia Berti Kewei Sun Haiming Zhang Federico Rosei Lifeng Chi Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices Institute of Functional Nano&Soft MaterialsSoochow UniversitySuzhou 215123China Centre Energie Matériaux et TélécommunicationsInstitut National de la Recherche Scientifique1650 Boulevard Lionel-BouletVarennesQCCanada Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China Deutsches Museum Museumsinsel 180538 MunichGermany Research Center for Advanced Measurement and Characterization National Institute for Materials ScienceTsukubaIbaraki 305-0047Japan

We report the systematic investigation of the effects of oxygen on the synthesis of 3 p sub-family armchair graphene nanoribbons(3 p-AGNRs),which revealed a strong catalytic effect with a reduction in the reaction temperature by approximately 180 K without degradation of the ***(para-phenylene)(3-AGNR)was generated through Ullmann-type coupling of4,4’’-dibromo-p-terphenyl on Cu(111),which was then converted into wider 3 p-AGNRs via lateral *** tunneling microscopy(STM)and X-ray photoelectron spectroscopy demonstrated the formation of different ribbons up to 12-AGNR,which contained regions exhibiting increased STM contrast that we attribute to the intercalation of Br atoms during lateral fusion.

关键词： on-surface synthesis graphene nanoribbons C–H activation scanning tunneling microscopy X-ray photoelectron spectroscopy

Numerical Analysis of Alternating-Current Small-Signal Response in graphene nanoribbons

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Chinese Physics Letters 2010年第8期27卷 172-175页

作者：陈志东张进宇余志平 Institute of Microelectronics Tsinghua University Beijing 100084

Alternating-current small-signal admittances of armchair graphene nanoribbons are investigated using the method of non-equilibrium Green＇s function. The calculated ac admittances show an oscillatory response between inductive and capacitive behaviors, which is a result of the finite length of the graphene nanoribbon. The effects of hydrogen-passivated edges on ac response are demonstrated. At low frequency, the edge effects transform the inductive behavior in a metallic graphene nanoribbon into a capacitive one. Finally, the effects of variations in the width and bandgap of a graphene nanoribbon on its dynamic response are investigated.

关键词： Numerical Analysis graphene nanoribbons Small-Signal