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Densely packed overlayer of iron phthalocyanine molecules grown on single-layer graphene

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Chinese Chemical Letters 2018年第1期29卷 183-186页

作者： Liwei Liu Wende Xiao jinhai mao Haigang Zhang YuhangJiang Haitao Zhou Kai Yang Hongjun Gao Institute of Physics Chinese Academy of Sciences Beijing 100190 China Beijing Institute of Technology Beijing 100081 China

The formation of densely packed overlayer of iron phthalocyanine （FePc） molecules on single-layer graphene （SLG） epitaxially grown on Ru（0001） is studied by means of low temperature scanning tunneling microscopy. We show that the FePc molecules form single molecular arrays, ordered honeycomb lattice, Kagome lattice and square lattice with increasing molecular coverage. The densely packed square lattice of the molecular layer is modulated by the moire pattern of SLGJRu（O001）. The superposition of the square lattice of the molecular layer on the hexagonal lattice of SLG molte pattern leads to the formation of a larger strip moire pattern. This coverage-dependent self-assembling behavior of FePc on SLG/Ru（0001 ） is mainly driven by the inhomogeneous electronic structure of graphene moire oattern, due to soatial-deoendent interracial charge transfer between SLG and Ru（0001 ） substrate.

关键词： Self-assemblyCoverage-dependentMetal phthalocyanineGrapheneScanning tunneling microscopy

Template-directed assembly of pentacene molecules on epitaxial graphene on Ru（0001）

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Nano Research 2013年第2期6卷 131-137页

作者： Haitao Zhou Lizhi Zhang jinhai mao Geng Li Yi Zhang Yeliang Wang Shixuan Du Werner A. Hofer Hong-Jun Gao Institute of Physics Chinese Academy of Sciences Belling 100190 China Stephenson Institute for Renewable Energy University of Liverpool Liverpool L69 3BX UK

The template-directed assembly of planar pentacene molecules on epitaxial graphene grown on Ru（0001）（G/Ru） has been investigated by means of low-temperature scanning tunneling microscopy （STM） and density functional theory （DFT） calculations. STM experiments find that pentacene adopts a highly selective and dispersed growth mode in the initial stage. By using DFT calculations including van der Waals interactions, we find that the configuration with pentacene adsorbed on face-centered cubic （fcc） regions of G/Ru is the most stable one, which accounts for the selective adsorption at low coverage. Moreover, at high coverage, we have successfully controlled the molecular assembly from amorphous, local ordering, to long-range order by optimizing the deposition rate and substrate temperature.

关键词： graphene Ru(0001) pentacene self-assembly scanning tunnelingmicroscopy (STM) density functionaltheory (DFT)

Construction of bilayer PdSe2 on epitaxial graphene

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Nano Research 2018年第11期11卷 5858-5865页

作者： En Li Dongfei Wang Peng Fan Ruizi Zhang Yu-Yang Zhang Geng Li jinhai mao Yeliang Wang Xiao Lin Shixuan Du Hong-Jun Gao Institute of Physics & University of Chinese Academy of Sciences Chinese Academy of Sciences Beijing 1 O0190 Chino

Two-dimensional (2D) materials have received significant attention due to their unique physical properties and potential applications in electronics and optoelectronics. Recent studies have demonstrated that exfoliated PdSe2, a layered transition metal dichalcogenide (TMD), exhibits ambipolar field-effect transistor (FET) behavior with notable performance and good air stability, and thus serves as an emerging candidate for 2D electronics. Here, we report the growth of bilayer PdSe2 on a graphene-SiC(0001) substrate by molecular beam epitaxy (MBE). A bandgap of 1.15 ± 0.07 eV was revealed by scanning tunneling spectroscopy (STS). Moreover, a bandgap shift of 0.2 eV was observed in PdSe2 layers grown on monolayer graphene as compared to those grown on bilayer graphene. The realization of nanoscale electronic junctions with atomically sharp boundaries in 2D PdSe2 implies the possibility of tuning its electronic or optoelectronic properties. In addition, on top of the PdSe2 bilayers, PdSe2 nanoribbons and stacks of nanoribbons with a fixed orientation have been fabricated. The bottom-up fabrication of low-dimensional PdSe2 structures is expected to enable substantial exploration of its potential applications.

关键词： two-dimensional materials transition-metal dichalcogenides PdSe 2 scanning tunneling microscopy/spectroscopy semiconducting bandgap nanoribbon

Boric Acid-Assisted Pyrolysis for High-Loading Single-Atom Catalysts to Boost Oxygen Reduction Reaction in Zn-Air Batteries

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Energy & Environmental Materials 2024年第2期7卷 106-114页

作者： Chenxi Xu Jiexing Wu Liang Chen Yi Gong Boyang mao Jincan Zhang jinhai Deng Mingxuan mao Yan Shi Zhaohui Hou Mengxue Cao Huanxin Li Haihui Zhou Zhongyuan Huang Yafei Kuang State Key Laboratory for Chemo/Biosensing and Chemometrics and College of Chemistry and Chemical Engineering Hunan University School of Chemistry and Chemical Engineering Key Laboratory of Hunan Province for Advanced Carbon-based Functional Materials Hunan Institute of Science and Technology Advanced Technology Institute University of Surrey Department of Engineering University of Cambridge King’s College London Department of Electrical and Electronic Engineering Imperial College London College of Materials and Metallurgy Guizhou University Department of Chemistry Physical & Theoretical Chemistry Laboratory University of Oxford

The emerging of single-atom catalysts（SACs） offers a great opportunity for the development of advanced energy storage and conversion devices due to their excellent activity and durability, but the actual mass production of high-loading SACs is still challenging. Herein, a facile and green boron acid（H3BO3）-assisted pyrolysis strategy is put forward to synthesize SACs by only using chitosan, cobalt salt and H3BO3as precursor, and the effect of H3BO3is deeply investigated. The results show that molten boron oxide derived from H3BO3as ideal high-temperature carbonization media and blocking media play important role in the synthesis process. As a result, the acquired Co/N/B tri-doped porous carbon framework（Co–N–B–C） not only presents hierarchical porous structure, large specific surface area and abundant carbon edges but also possesses high-loading single Co atom（4.2 wt.%）, thus giving rise to outstanding oxygen catalytic performance. When employed as a catalyst for air cathode in Zn-air batteries, the resultant Co–N–B–C catalyst shows remarkable power density and long-term stability. Clearly, our work gains deep insight into the role of H3BO3and provides a new avenue to synthesis of high-performance SACs.

关键词： boric acid oxygen reduction reaction single-atom catalysts Zn-air batteries

Intercalation of metals and silicon at the interface of epitaxial graphene and its substrates

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Intercalation of metals and silicon at the interface of epit...

Emergence of correlations in twisted monolayer-trilayer graphene heterostructures

中国真空学会2014学术年会

作者： Li Huang Wenyan Xu Yande Que jinhai mao Lei Meng Lida Pan Geng Li Yeliang Wang Shixuan Du YunQi Liu Hong-Jun Gao Institute of Chemistry Chinese Academy of Sciences Institute of Physics Chinese Academy of Sciences

Intercalations of metals and silicon between epitaxial graphene and its substrates are *** metal intercalation,seven different metals have been successfully intercalated at the interface of graphene/Ru(0001)and form different intercalated ***,graphene maintains its original high quality after the intercalation and shows features of weakened interaction with the *** silicon intercalation,two systems,graphene on Ru(0001)and on Ir(111),have been *** both cases,graphene preserves its high quality and regains its original superlative properties after the silicon *** importantly,we demonstrate that thicker silicon layers can be intercalated at the interface,which allows the atomic control of the distance between graphene and the metal *** results show the great potential of the intercalation method as a non-damaging approach to decouple epitaxial graphene from its substrates and even form a dielectric layer for future electronic applications.

关键词： graphene metal intercalation silicon intercalation scanning tunneling microscopy

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中国物理B:英文版 2023年第9期32卷 74-78页

作者：周璋 Kenji Watanabe Takashi Taniguchi 林晓毛金海高鸿钧 School of Physical Sciences and CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100049China Advanced Materials Laboratory National Institute for Materials ScienceTsukuba305-0044Japan Institute of Physics Chinese Academy of SciencesBeijing 100190China

Twisted bilayer graphene heterostructures have recently emerged as a well-established platform for studying strongly correlated phases,such as correlated insulating,superconducting,and topological *** this notion to twisted multilayer graphene heterostructures has exhibited more diverse correlated phases,as some fundamental properties related to symmetry and band structures are correspondingly ***,we report the observations of correlated states in twisted monolayer-trilayer(Bernal stacked)graphene *** phases at integer fillings of the moire unit cell are revealed at a high displacement field and stabilized with a moderate magnetic field on the electron-doping side at a twist angle of 1.45°,where the lift of degeneracy at the integer fillings is observed in the Landau fan *** results demonstrate the effectiveness of moire engineering in an extended structure and provide insights into electric-field tunable correlated phases.

关键词： twisted multilayer graphene correlated states electric tuning

Gate-controlled localization to delocalization transition of flat band wavefunction in twisted monolayer–bilayer graphene

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Chinese Physics B 2023年第6期32卷 102-105页

作者：李思宇王政文薛禹承曹路 Kenji Watanabe Takashi Taniguchi 高鸿钧毛金海 Institute of Physics Chinese Academy of SciencesBeijing 100190China School of Physical Sciences and CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100049China College of Materials Science and Optoelectronic Technology Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China Advanced Materials Laboratory National Institute for Materials ScienceTsukuba 305-0044Japan

Twisted graphene systems with flat bands have attracted much attention for they are excellent platforms to research novel quantum phases. Recently, transport measurements about twisted monolayer–bilayer graphene(t MBG) have shown the existence of correlated states and topological states in this system. However, the direct observations of the band structures and the corresponding spatial distributions are still not sufficient. Here we show that the distributions of flat bands in t MBG host two different modes by scanning tunneling microscopy and spectroscopy(STM/S). By tuning our t MBG device from the empty filling state to the full filling state through the back gate, we observe that the distributions of two flat bands develop from localized mode to delocalized mode. This gate-controlled flat band wavefunction polarization is unique to the t MBG system. Our work suggests that t MBG is promising to simulate both twisted bilayer graphene(TBG) and twisted double bilayer graphene(t DBG) and would be an ideal platform to explore novel moiré physics.

关键词： graphene Van der Waals heterostructures scanning tunneling microscopy/spectroscopy

THREE DIMENSIONAL NONLINEAR NUMERICAL MODEL WITH INCLINED PRESSURE FOR SALTWATER INTRUSION AT THE YANGTZE RIVER ESTUARY

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Journal of Hydrodynamics 2000年第1期12卷 57-66页

作者： Zhu, Yuliang Zheng, jinhai mao, Lihua Yan, Yixin Hehai Univ Nanjing China

A three-dimensional nonlinear numerical model with inclined pressure was developed to compute the saltwater intrusion at the Yangtze River Estuary. The σ-transformation was introduced in the vertical plane to achieve the same lattices in the whole domain of interest. The mode-splitting technique can be used to split the three-dimensional governing equations into the surface gravity waves (external mode) and the internal gravity waves (internal mode). And the external mode was solved by the improved double-sweep-implicit (DSI) finite difference method and the internal mode was solved by the Eulerian-Lagrangian method. The Eulerian-Lagrangian method can not only reduce the numerical diffusion but also increase the computational accuracy through the improvement of the finite difference scheme in the vertical direction. The application of the model to the Yangtze River Estuary was carried out for the calculation of the saltwater intrusion and the null point. Results of the temporal and spatial distribution of the flow velocity and the salinity coincide with the measured data quite well. The formation and location of the underwater sandbars in the North Channel of the Yangtze River Estuary are closely related to the local salinity, the null point, the predominant current and the residual flow.

关键词： Flow of water Mathematical models Percolation (fluids) Seawater Three dimensional

Stability of GM(1,1) power model on vector transformation

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Journal of Systems Engineering and Electronics 2015年第1期26卷 103-109页

作者： jinhai Guo Xinping Xiao Jun Liu Shuhua mao School of Science Wuhan University of Technology School of Information and Mathematics Yangtze University

The morbidity problem of the GM（1,1） power model in parameter identification is discussed by using multiple and rotation transformation of vectors. Firstly we consider the morbidity problem of the special matrix and prove that the condition number of the coefficient matrix is determined by the ratio of lengths and the included angle of the column vector, which could be adjusted by multiple and rotation transformation to turn the matrix to a well-conditioned one. Then partition the corresponding matrix of the GM（1,1） power model in accordance with the column vector and regulate the matrix to a well-conditioned one by multiple and rotation transformation of vectors, which completely solve the instability problem of the GM（1,1） power model. Numerical results show that vector transformation is a new method in studying the stability problem of the GM（1,1） power model.

关键词： grey power model stability morbidity vector transformation condition number of matrix