As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine properties.Fractal analysis has been used to characterize the shapes of metal...As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine properties.Fractal analysis has been used to characterize the shapes of metal materials at various scales and dimensions.Conventional methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and interfaces.However,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal materials.From the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear surfaces.The relationship between the fractal dimensions and properties of metal material surfaces and interfaces is summarized.Starting from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be developed.It is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.展开更多
The exploration of efficient and earth‐rich electrocatalysts for electrochemical reactions is critical to the implementation of large‐scale green energy conversion and storage techniques.Two‐dimensional(2D)material...The exploration of efficient and earth‐rich electrocatalysts for electrochemical reactions is critical to the implementation of large‐scale green energy conversion and storage techniques.Two‐dimensional(2D)materials with distinctive structural and electrochemical properties provide fertile soil for researchers to harvest basic science and emerging applications,which can be divided into metal‐free materials(such as graphene,carbon nitride and black phosphorus)and transition metal‐based materials(such as halogenides,phosphates,oxides,hydroxides,and MXenes).For faultless 2D materials,they usually exhibit poor electrochemical hydrogen evolution reaction(HER)activity because only edge sites can be available while the base surface is chemically inactive.Defect engineering is an effective strategy to generate active sites in 2D materials for improving electrocatalytic activity.This review presents feasible design strategies for constructing defect sites(including edge defects,vacancy defects and dopant derived defects)in 2D materials to improve their HER performance.The essential relationships between defect structures and electrocatalytic HER performance are discussed in detail,providing valuable guidance for rationally fabricating efficient HER electrocatalysts.The hydrogen adsorption/desorption energy can be optimized by constructing defect sites at different locations and by adjusting the local electronic structure to form unsaturated coordination states for efficient HER.展开更多
Phased array radar is the main sensor in a battlefield.Phased array antenna is the main execution unit of the phased array radar,and it greatly affects the reliability of the phased array radar. As a result,the fragme...Phased array radar is the main sensor in a battlefield.Phased array antenna is the main execution unit of the phased array radar,and it greatly affects the reliability of the phased array radar. As a result,the fragment damaged antenna test is important.As the materials of phased array antenna are not easy to get,the fragment damaged antenna test is difficult to carry out. Then we present a study on this problem and introduce the principles of dimensional analysis to solve it. Firstly, the fragments damage antenna target dimensionless model is constructed. Secondly,the finite element analysis software ANSYS / LS-DYNA are used to carry out a large number of different materials simulation test for dimensional analysis. Finally,based on dimensional test analysis,the materials equivalent empirical model between different antennas target is presented in the same damage. The results of this study provide a feasible and valuable solution for different materials' target damaged test.展开更多
Two-dimensional （2D） materials, such as graphene, phosphorene, and transition metal dichalcogenides （e.g., MoS2 and WS2）, have attracted a great deal of attention recently due to their extraordinary structural, me...Two-dimensional （2D） materials, such as graphene, phosphorene, and transition metal dichalcogenides （e.g., MoS2 and WS2）, have attracted a great deal of attention recently due to their extraordinary structural, mechanical, and physical properties. In particular, 2D materials have shown great potential for thermal management and thermoelectric energy generation. In this article, we review the recent advances in the study of thermal properties of 2D materials. We first review some important aspects in thermal conductivity of graphene and discuss the possibility to enhance the ultra-high thermal conductivity of graphene. Next, we discuss thermal conductivity of MoS2 and the new strategy for thermal management of MoS2 device. Subsequently, we discuss the anisotropic thermal properties of phosphorene. Finally, we review the application of 2D materials in thermal devices, including thermal rectifier and thermal modulator.展开更多
Two-dimensional （2D） materials, e.g., graphene, transition metal dichalcogenides （TMDs）, and black phosphorus （BP）, have demonstrated fascinating electrical and optical characteristics and exhibited great potent...Two-dimensional （2D） materials, e.g., graphene, transition metal dichalcogenides （TMDs）, and black phosphorus （BP）, have demonstrated fascinating electrical and optical characteristics and exhibited great potential in optoelectronic applications. High-performance and multifunctional devices were achieved by employing diverse designs, such as hybrid systems with nanostructured materials, bulk semiconductors and organics, forming 2D heterostructures. In this review, we mainly discuss the recent progress of 2D materials in high-responsive photodetectors, light-emitting devices and single photon emitters. Hybrid systems and van der Waals heterostructure-based devices are emphasized, which exhibit great potential in state-of-the-art applications.展开更多
Angle-resolved polarized Raman（ARPR） spectroscopy can be utilized to assign the Raman modes based on crystal symmetry and Raman selection rules and also to characterize the crystallographic orientation of anisotropi...Angle-resolved polarized Raman（ARPR） spectroscopy can be utilized to assign the Raman modes based on crystal symmetry and Raman selection rules and also to characterize the crystallographic orientation of anisotropic materials.However, polarized Raman measurements can be implemented by several different configurations and thus lead to different results. In this work, we systematically analyze three typical polarization configurations： 1） to change the polarization of the incident laser, 2） to rotate the sample, and 3） to set a half-wave plate in the common optical path of incident laser and scattered Raman signal to simultaneously vary their polarization directions. We provide a general approach of polarization analysis on the Raman intensity under the three polarization configurations and demonstrate that the latter two cases are equivalent to each other. Because the basal plane of highly ordered pyrolytic graphite（HOPG） exhibits isotropic feature and its edge plane is highly anisotropic, HOPG can be treated as a modelling system to study ARPR spectroscopy of twodimensional materials on their basal and edge planes. Therefore, we verify the ARPR behaviors of HOPG on its basal and edge planes at three different polarization configurations. The orientation direction of HOPG edge plane can be accurately determined by the angle-resolved polarization-dependent G mode intensity without rotating sample, which shows potential application for orientation determination of other anisotropic and vertically standing two-dimensional materials and other materials.展开更多
High-performance photodetectors are expected to open up revolutionary opportunities in many application fields, such as environment monitoring, military, optical communication and biomedical science. Combining two-dim...High-performance photodetectors are expected to open up revolutionary opportunities in many application fields, such as environment monitoring, military, optical communication and biomedical science. Combining two-dimensional materials(which have tunable optical absorption and high carrier mobility) with organic materials(which are abundant with low cost, high flexibility and large-area scalability) to form thin-film heterojunctions, high-responsivity photodetectors could be predicted with fast response speed in a wide spectra region.In this review, we give a comprehensive summary of photodetectors based on two-dimensional materials and organic thin-film heterojunctions, which includes hybrid assisted enhanced devices, single-layer enhanced devices, vertical heterojunction devices and tunable vertical heterojunction devices. We also give a systematic classification and perspectives on the future development of these types of photodetectors.展开更多
In recent years, structure design and predictions based on global optimization approach as implemented in CALYPSO software have gained great success in accelerating the discovery of novel two-dimensional(2D) materials...In recent years, structure design and predictions based on global optimization approach as implemented in CALYPSO software have gained great success in accelerating the discovery of novel two-dimensional(2D) materials. Here we highlight some most recent research progress on the prediction of novel 2D structures, involving elements, metal-free and metal-containing compounds using CALYPSO package. Particular emphasis will be given to those 2D materials that exhibit unique electronic and magnetic properties with great potentials for applications in novel electronics, optoelectronics,magnetronics, spintronics, and photovoltaics. Finally, we also comment on the challenges and perspectives for future discovery of multi-functional 2D materials.展开更多
Two-dimensional （2D） materials, such as graphene and MoS2 related transition metal dichalcogenides （TMDC）, have attracted much attention for their potential applications. Ferroelectrics, one of the special and tra...Two-dimensional （2D） materials, such as graphene and MoS2 related transition metal dichalcogenides （TMDC）, have attracted much attention for their potential applications. Ferroelectrics, one of the special and traditional dielectric materials, possess a spontaneous electric polarization that can be reversed by the application of an external electric field. In recent years, a new type of device, combining 2D materials with ferroelectrics, has been fabricated. Many novel devices have been fabricated, such as low power consumption memory devices, highly sensitive photo-transistors, etc. using this technique of hybrid systems incorporating ferroelectrics and 2D materials. This paper reviews two types of devices based on field effect transistor （FET） structures with ferroelectric gate dielectric construction （termed FeFET）. One type of device is for logic applications, such as a graphene and TMDC FeFET for fabricating memory units. Another device is for optoelectric applications, such as high performance phototransistors using a graphene p-n junction. Finally, we discuss the prospects for future applications of 2D material FeFET.展开更多
Two-dimensional（2D） materials have been regarded as a promising nonlinear optical medium for fabricating versatile optical and optoelectronic devices. Among the various photonic applications, the employment of 2D ma...Two-dimensional（2D） materials have been regarded as a promising nonlinear optical medium for fabricating versatile optical and optoelectronic devices. Among the various photonic applications, the employment of 2D materials as nonlinear optical devices such as saturable absorbers for ultrashort pulse generation and shaping in ultrafast lasers is one of the most striking aspects in recent years. In this paper, we review the recent progress of 2D materials based pulse generation and soliton shaping in ultrafast fiber lasers, and particularly in the context of 2D materials-decorated microfiber photonic devices. The fabrication of 2D materials-decorated microfiber photonic devices, high performance mode-locked pulse generation, and the nonlinear soliton dynamics based on pulse shaping method are discussed. Finally, the challenges and the perspective of the 2D materials-based photonic devices as well as their applications are also discussed.展开更多
Field-effect transistors （FETs） for logic applications, graphene and MoS2, are discussed. These materials have based on two representative two-dimensional （2D） materials, drastically different properties and requi...Field-effect transistors （FETs） for logic applications, graphene and MoS2, are discussed. These materials have based on two representative two-dimensional （2D） materials, drastically different properties and require different consider- ations. The unique band structure of graphene necessitates engineering of the Dirac point, including the opening of the bandgap, the doping and the interface, before the graphene can be used in logic applications. On the other hand, MoS2 is a semiconductor, and its electron transport depends heavily on the surface properties, the number of layers, and the carrier density. Finally, we discuss the prospects for the future developments in 2D material transistors.展开更多
Recent studies in van der Waals coupled two-dimensional(2D) bilayer materials have demonstrated a new freedom for material engineering by the formation of moiré pattern. By tuning the twist angle between two laye...Recent studies in van der Waals coupled two-dimensional(2D) bilayer materials have demonstrated a new freedom for material engineering by the formation of moiré pattern. By tuning the twist angle between two layers, one can modulate their electronic band structures and therefore the associated electrical transport and optical properties, which are distinct from the original ones of each individual layer. These new properties excite great passion in the exploration of new quantum states and possible applications of 2D bilayers. In this article, we will mainly review the prevailing fabrication methods and emerging physical properties of twisted bilayer materials and lastly give out a perspective of this topic.展开更多
Thermoelectric generators have attracted a wide research interest owing to their ability to directly convert heat into electrical power.Moreover,the thermoelectric properties of traditional inorganic and organic mater...Thermoelectric generators have attracted a wide research interest owing to their ability to directly convert heat into electrical power.Moreover,the thermoelectric properties of traditional inorganic and organic materials have been significantly improved over the past few decades.Among these compounds,layered two-dimensional(2D)materials,such as graphene,black phosphorus,transition metal dichalcogenides,IVA–VIA compounds,and MXenes,have generated a large research attention as a group of potentially high-performance thermoelectric materials.Due to their unique electronic,mechanical,thermal,and optoelectronic properties,thermoelectric devices based on such materials can be applied in a variety of applications.Herein,a comprehensive review on the development of 2D materials for thermoelectric applications,as well as theoretical simulations and experimental preparation,is presented.In addition,nanodevice and new applications of 2D thermoelectric materials are also introduced.At last,current challenges are discussed and several prospects in this field are proposed.展开更多
We review experimental and theoretical results on thermal transport in semiconductor nanostructures（multilayer thin films, core/shell and segmented nanowires）, single-and few-layer graphene, hexagonal boron nitride,...We review experimental and theoretical results on thermal transport in semiconductor nanostructures（multilayer thin films, core/shell and segmented nanowires）, single-and few-layer graphene, hexagonal boron nitride, molybdenum disulfide, and black phosphorus. Different possibilities of phonon engineering for optimization of electrical and heat conductions are discussed. The role of the phonon energy spectra modification on the thermal conductivity in semiconductor nanostructures is revealed. The dependence of thermal conductivity in graphene and related two-dimensional（2 D） materials on temperature, flake size, defect concentration, edge roughness, and strain is analyzed.展开更多
Two-dimensional(2D) materials, such as graphene, transition metal dichalcogenides(TMDs), black phosphorus(BP),and related derivatives, have attracted great attention due to their advantages of flexibility, strong ligh...Two-dimensional(2D) materials, such as graphene, transition metal dichalcogenides(TMDs), black phosphorus(BP),and related derivatives, have attracted great attention due to their advantages of flexibility, strong light–matter interaction,broadband absorption, and high carrier mobility, and have become a powerful contender for next-generation infrared photodetectors. However, since the thickness of 2D materials is on the order of nanometers, the absorption of 2D materials is very weak, which limits the detection performance of 2D materials-based infrared photodetectors. In order to solve this problem, scientific researchers have tried to use optimized device structures to combine with 2D materials for improving the performance of infrared photodetectors. In this review, we review the progress of room-temperature infrared photodetectors with hybrid structure based on 2D materials in recent years, focusing mainly on 2D–nD(n = 0, 1, 2) heterostructures, the integration between 2D materials and on-chip or plasmonic structure. Finally, we summarize the current challenges and point out the future development direction.展开更多
The characterization of microstructure for three kinds of typical low dimensional materials,such as ultrafine particle(zero- dimension),whisker(one- dimension)and thin film(two-dimensions),has been carried out.The met...The characterization of microstructure for three kinds of typical low dimensional materials,such as ultrafine particle(zero- dimension),whisker(one- dimension)and thin film(two-dimensions),has been carried out.The methods and criteria for the characterization are investigated and introduced.Some interesting results of the characterization are reported.展开更多
This paper,based on the New Curriculum Standards,researched the content of the curriculum for the newly edited material for High school English and gave suggestion on material adaptation for both curriculum designers ...This paper,based on the New Curriculum Standards,researched the content of the curriculum for the newly edited material for High school English and gave suggestion on material adaptation for both curriculum designers and classroom teachers.展开更多
An ultraviolet（UV） curable support material pre-polymer for three dimensional printing was prepared based on the synergistic effect between PEO-PPO-PEO tri-block copolymer（F127） and polyethylene glycol （400） di-...An ultraviolet（UV） curable support material pre-polymer for three dimensional printing was prepared based on the synergistic effect between PEO-PPO-PEO tri-block copolymer（F127） and polyethylene glycol （400） di-acrylate（SR344）. The effects of jetting conditions, thermal stability, curing time, mechanical properties and shrinking rate on printing models were studied. The situation of removing support material from build model was investigated after building progress was completed. The experimental result shows that when F127 is 6.0wt%, SR344 is 20.0wt%, 4-Methoxy phenol is 0.15wt% and Irgacure 2959 is 1.5wt%, the support material pre-polymer could be jetted out from the nozzles smoothly during building up of three dimensional printing models at 50-55 ℃. In addition, the support material could be removed easily from building model without spoiling the model; furthermore, the forming precision of building model is improved.展开更多
With the increasing demand for large-scale battery systems in electric vehicles（EVs） and smart renewable energy grids, organic materials including small molecules and polymers utilized as electrodes in rechargeable ...With the increasing demand for large-scale battery systems in electric vehicles（EVs） and smart renewable energy grids, organic materials including small molecules and polymers utilized as electrodes in rechargeable batteries have received increasing attraction. In recent years, two-dimensional（2D） organic materials possessing planar layered architecture exhibit optional chemical modification, high specific surface area as well as unique electrical/magnetic properties, which have been emerging as the promising functional materials for wide applications in optoelectronics, catalysis, sensing, etc. Integrating with high-density redox-active sites and hierarchical porous structure, significant achievements in 2D organic materials as cathode materials for alkali-metal-ion batteries have been witnessed. In this review, the recent progress in synthetic approaches, structure analyses, electrochemical characterizations of 2D organic materials as well as their application in alkali-metal-ion batteries containing lithium ion battery（LIB）, lithium sulfur battery（LSB）, lithium air battery（LAB） and sodium ion battery（SIB） are summarized systematically,and their current challenges including cycling stability and electron conductivity for cathode materials in battery fields are also discussed.展开更多
Grain crushing plays an important role in one-dimensional (1D) compression and creep behaviors of granular materials under high stress. It is clear that the macro-properties of granular materials are closely related t...Grain crushing plays an important role in one-dimensional (1D) compression and creep behaviors of granular materials under high stress. It is clear that the macro-properties of granular materials are closely related to the micro-fracture properties of grains in 1D compression and creep tests. In this paper, a series of 1D compression and creep tests were performed on Ottawa sand to investigate the deformation and grain crushing properties of granular materials, and it shows that the void ratio is correlated to the grain crushing amount (the quantity of crushed grains) for granular materials subjected to grain crushing. The test results, combining with the existing test data related to grain crushing of granular materials, were used to verify the relation. Moreover, the implications of these relations on the yield of granular material, and the equivalent effect of stress and time in changing soil fabric are presented.展开更多
基金financially supported by the National Key R&D Program of China(No.2022YFE0121300)the National Natural Science Foundation of China(No.52374376)the Introduction Plan for High-end Foreign Experts(No.G2023105001L)。
文摘As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine properties.Fractal analysis has been used to characterize the shapes of metal materials at various scales and dimensions.Conventional methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and interfaces.However,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal materials.From the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear surfaces.The relationship between the fractal dimensions and properties of metal material surfaces and interfaces is summarized.Starting from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be developed.It is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.
文摘The exploration of efficient and earth‐rich electrocatalysts for electrochemical reactions is critical to the implementation of large‐scale green energy conversion and storage techniques.Two‐dimensional(2D)materials with distinctive structural and electrochemical properties provide fertile soil for researchers to harvest basic science and emerging applications,which can be divided into metal‐free materials(such as graphene,carbon nitride and black phosphorus)and transition metal‐based materials(such as halogenides,phosphates,oxides,hydroxides,and MXenes).For faultless 2D materials,they usually exhibit poor electrochemical hydrogen evolution reaction(HER)activity because only edge sites can be available while the base surface is chemically inactive.Defect engineering is an effective strategy to generate active sites in 2D materials for improving electrocatalytic activity.This review presents feasible design strategies for constructing defect sites(including edge defects,vacancy defects and dopant derived defects)in 2D materials to improve their HER performance.The essential relationships between defect structures and electrocatalytic HER performance are discussed in detail,providing valuable guidance for rationally fabricating efficient HER electrocatalysts.The hydrogen adsorption/desorption energy can be optimized by constructing defect sites at different locations and by adjusting the local electronic structure to form unsaturated coordination states for efficient HER.
文摘Phased array radar is the main sensor in a battlefield.Phased array antenna is the main execution unit of the phased array radar,and it greatly affects the reliability of the phased array radar. As a result,the fragment damaged antenna test is important.As the materials of phased array antenna are not easy to get,the fragment damaged antenna test is difficult to carry out. Then we present a study on this problem and introduce the principles of dimensional analysis to solve it. Firstly, the fragments damage antenna target dimensionless model is constructed. Secondly,the finite element analysis software ANSYS / LS-DYNA are used to carry out a large number of different materials simulation test for dimensional analysis. Finally,based on dimensional test analysis,the materials equivalent empirical model between different antennas target is presented in the same damage. The results of this study provide a feasible and valuable solution for different materials' target damaged test.
基金Project supported by the Science and Engineering Research Council,Singapore(Grant No.152-70-00017)the Agency for Science,Technology and Research(A*STAR)Singapore
文摘Two-dimensional （2D） materials, such as graphene, phosphorene, and transition metal dichalcogenides （e.g., MoS2 and WS2）, have attracted a great deal of attention recently due to their extraordinary structural, mechanical, and physical properties. In particular, 2D materials have shown great potential for thermal management and thermoelectric energy generation. In this article, we review the recent advances in the study of thermal properties of 2D materials. We first review some important aspects in thermal conductivity of graphene and discuss the possibility to enhance the ultra-high thermal conductivity of graphene. Next, we discuss thermal conductivity of MoS2 and the new strategy for thermal management of MoS2 device. Subsequently, we discuss the anisotropic thermal properties of phosphorene. Finally, we review the application of 2D materials in thermal devices, including thermal rectifier and thermal modulator.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61422503 and 61376104)the Open Research Funds of Key Laboratory of MEMS of Ministry of Education of Chinathe Fundamental Research Funds for the Central Universities of China
文摘Two-dimensional （2D） materials, e.g., graphene, transition metal dichalcogenides （TMDs）, and black phosphorus （BP）, have demonstrated fascinating electrical and optical characteristics and exhibited great potential in optoelectronic applications. High-performance and multifunctional devices were achieved by employing diverse designs, such as hybrid systems with nanostructured materials, bulk semiconductors and organics, forming 2D heterostructures. In this review, we mainly discuss the recent progress of 2D materials in high-responsive photodetectors, light-emitting devices and single photon emitters. Hybrid systems and van der Waals heterostructure-based devices are emphasized, which exhibit great potential in state-of-the-art applications.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFA0301204)the National Natural Science Foundation of China(Grant Nos.11604326,11434010,11474277,and 11225421)
文摘Angle-resolved polarized Raman（ARPR） spectroscopy can be utilized to assign the Raman modes based on crystal symmetry and Raman selection rules and also to characterize the crystallographic orientation of anisotropic materials.However, polarized Raman measurements can be implemented by several different configurations and thus lead to different results. In this work, we systematically analyze three typical polarization configurations： 1） to change the polarization of the incident laser, 2） to rotate the sample, and 3） to set a half-wave plate in the common optical path of incident laser and scattered Raman signal to simultaneously vary their polarization directions. We provide a general approach of polarization analysis on the Raman intensity under the three polarization configurations and demonstrate that the latter two cases are equivalent to each other. Because the basal plane of highly ordered pyrolytic graphite（HOPG） exhibits isotropic feature and its edge plane is highly anisotropic, HOPG can be treated as a modelling system to study ARPR spectroscopy of twodimensional materials on their basal and edge planes. Therefore, we verify the ARPR behaviors of HOPG on its basal and edge planes at three different polarization configurations. The orientation direction of HOPG edge plane can be accurately determined by the angle-resolved polarization-dependent G mode intensity without rotating sample, which shows potential application for orientation determination of other anisotropic and vertically standing two-dimensional materials and other materials.
基金Project supported by National Science Funds for Creative Research Groups of China(Grant No.61421002)
文摘High-performance photodetectors are expected to open up revolutionary opportunities in many application fields, such as environment monitoring, military, optical communication and biomedical science. Combining two-dimensional materials(which have tunable optical absorption and high carrier mobility) with organic materials(which are abundant with low cost, high flexibility and large-area scalability) to form thin-film heterojunctions, high-responsivity photodetectors could be predicted with fast response speed in a wide spectra region.In this review, we give a comprehensive summary of photodetectors based on two-dimensional materials and organic thin-film heterojunctions, which includes hybrid assisted enhanced devices, single-layer enhanced devices, vertical heterojunction devices and tunable vertical heterojunction devices. We also give a systematic classification and perspectives on the future development of these types of photodetectors.
基金support by Australian Research Council under Discovery Project (Grant No. DP170103598)the Pawsey Supercomputing Centre through the National Computational Merit Allocation Scheme supported by the Australian Government and the Government of Western Australia
文摘In recent years, structure design and predictions based on global optimization approach as implemented in CALYPSO software have gained great success in accelerating the discovery of novel two-dimensional(2D) materials. Here we highlight some most recent research progress on the prediction of novel 2D structures, involving elements, metal-free and metal-containing compounds using CALYPSO package. Particular emphasis will be given to those 2D materials that exhibit unique electronic and magnetic properties with great potentials for applications in novel electronics, optoelectronics,magnetronics, spintronics, and photovoltaics. Finally, we also comment on the challenges and perspectives for future discovery of multi-functional 2D materials.
基金Project supported by the Major State Basic Research Development Program of China(Grant Nos.2013CB922302 and 2016YFA0203900)the Natural Science Foundation of China(Grant Nos.11322441,614404147,61574152,and 61674157)the Key Research Project of Frontier Science of Chinese Academy of Sciences(Grant Nos.QYZDB-SSW-JSC016 and QYZDB-SSW-JSC031)
文摘Two-dimensional （2D） materials, such as graphene and MoS2 related transition metal dichalcogenides （TMDC）, have attracted much attention for their potential applications. Ferroelectrics, one of the special and traditional dielectric materials, possess a spontaneous electric polarization that can be reversed by the application of an external electric field. In recent years, a new type of device, combining 2D materials with ferroelectrics, has been fabricated. Many novel devices have been fabricated, such as low power consumption memory devices, highly sensitive photo-transistors, etc. using this technique of hybrid systems incorporating ferroelectrics and 2D materials. This paper reviews two types of devices based on field effect transistor （FET） structures with ferroelectric gate dielectric construction （termed FeFET）. One type of device is for logic applications, such as a graphene and TMDC FeFET for fabricating memory units. Another device is for optoelectric applications, such as high performance phototransistors using a graphene p-n junction. Finally, we discuss the prospects for future applications of 2D material FeFET.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61307058,61378036,11304101,and 11474108)Guangdong Natural Science Funds for Distinguished Young Scholar,China(Grant No.2014A030306019)+6 种基金Pearl River S&T Nova Program of Guangzhou,China(Grant No.2014J2200008)Program for Outstanding Innovative Young Talents of Guangdong Province,China(Grant No.2014TQ01X220)Program for Outstanding Young Teachers in Guangdong Higher Education Institutes,China(Grant No.YQ2015051)Science and Technology Project of Guangdong,China(Grant No.2016B090925004)Foundation for Young Talents in Higher Education of Guangdong,China(Grant No.2017KQNCX051)Science and Technology Program of Guangzhou,China(Grant No.201607010245)Scientific Research Foundation of Young Teacher of South China Normal University,China(Grant No.17KJ09)
文摘Two-dimensional（2D） materials have been regarded as a promising nonlinear optical medium for fabricating versatile optical and optoelectronic devices. Among the various photonic applications, the employment of 2D materials as nonlinear optical devices such as saturable absorbers for ultrashort pulse generation and shaping in ultrafast lasers is one of the most striking aspects in recent years. In this paper, we review the recent progress of 2D materials based pulse generation and soliton shaping in ultrafast fiber lasers, and particularly in the context of 2D materials-decorated microfiber photonic devices. The fabrication of 2D materials-decorated microfiber photonic devices, high performance mode-locked pulse generation, and the nonlinear soliton dynamics based on pulse shaping method are discussed. Finally, the challenges and the perspective of the 2D materials-based photonic devices as well as their applications are also discussed.
基金supported by the National Basic Research Program of China (Grant No. 2013CBA01600)the National Natural Science Foundation of China (Grant Nos. 61261160499 and 11274154)+2 种基金the National Science and Technology Major Project of the Ministry of Science and Technology of China (Grant No. 2011ZX02707)the Natural Science Foundation of Jiangsu Province, China (Grant No. BK2012302)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120091110028)
文摘Field-effect transistors （FETs） for logic applications, graphene and MoS2, are discussed. These materials have based on two representative two-dimensional （2D） materials, drastically different properties and require different consider- ations. The unique band structure of graphene necessitates engineering of the Dirac point, including the opening of the bandgap, the doping and the interface, before the graphene can be used in logic applications. On the other hand, MoS2 is a semiconductor, and its electron transport depends heavily on the surface properties, the number of layers, and the carrier density. Finally, we discuss the prospects for the future developments in 2D material transistors.
基金Project supported by the National Key R&D Program of China(Grant Nos.2016YFA0300903 and 2016YFA0300804)National Equipment Program of China(Grant No.ZDYZ2015-1)+3 种基金Beijing Graphene Innovation Program,China(Grant No.Z181100004818003)Beijing Municipal Science&Technology Commission,China(Grant No.Z181100004218006)Bureau of Industry and Information Technology of Shenzhen,China(Graphene platform contract No.201901161512)the Key R&D Program of Guangdong Province,China(Grant No.2019B010931001)
文摘Recent studies in van der Waals coupled two-dimensional(2D) bilayer materials have demonstrated a new freedom for material engineering by the formation of moiré pattern. By tuning the twist angle between two layers, one can modulate their electronic band structures and therefore the associated electrical transport and optical properties, which are distinct from the original ones of each individual layer. These new properties excite great passion in the exploration of new quantum states and possible applications of 2D bilayers. In this article, we will mainly review the prevailing fabrication methods and emerging physical properties of twisted bilayer materials and lastly give out a perspective of this topic.
基金supported by National Science Foundation for Young Scientists of China (No.61905161 and 51702219)the National Natural Science Foundation of China (No.61975134,61875138 and 61775147)+1 种基金the Science and Technology Innovation Commission of Shenzhen (No. JCYJ20180206121837007)the Shenzhen Nanshan District Pilotage Team Program (LHTD20170006)
文摘Thermoelectric generators have attracted a wide research interest owing to their ability to directly convert heat into electrical power.Moreover,the thermoelectric properties of traditional inorganic and organic materials have been significantly improved over the past few decades.Among these compounds,layered two-dimensional(2D)materials,such as graphene,black phosphorus,transition metal dichalcogenides,IVA–VIA compounds,and MXenes,have generated a large research attention as a group of potentially high-performance thermoelectric materials.Due to their unique electronic,mechanical,thermal,and optoelectronic properties,thermoelectric devices based on such materials can be applied in a variety of applications.Herein,a comprehensive review on the development of 2D materials for thermoelectric applications,as well as theoretical simulations and experimental preparation,is presented.In addition,nanodevice and new applications of 2D thermoelectric materials are also introduced.At last,current challenges are discussed and several prospects in this field are proposed.
基金Project supported by the Republic of Moldova through the projects 15.817.02.29F and 17.80013.16.02.04/Ua
文摘We review experimental and theoretical results on thermal transport in semiconductor nanostructures（multilayer thin films, core/shell and segmented nanowires）, single-and few-layer graphene, hexagonal boron nitride, molybdenum disulfide, and black phosphorus. Different possibilities of phonon engineering for optimization of electrical and heat conductions are discussed. The role of the phonon energy spectra modification on the thermal conductivity in semiconductor nanostructures is revealed. The dependence of thermal conductivity in graphene and related two-dimensional（2 D） materials on temperature, flake size, defect concentration, edge roughness, and strain is analyzed.
基金Project supported by the National Natural Science Foundation of China(Grant No.61704061)
文摘Two-dimensional(2D) materials, such as graphene, transition metal dichalcogenides(TMDs), black phosphorus(BP),and related derivatives, have attracted great attention due to their advantages of flexibility, strong light–matter interaction,broadband absorption, and high carrier mobility, and have become a powerful contender for next-generation infrared photodetectors. However, since the thickness of 2D materials is on the order of nanometers, the absorption of 2D materials is very weak, which limits the detection performance of 2D materials-based infrared photodetectors. In order to solve this problem, scientific researchers have tried to use optimized device structures to combine with 2D materials for improving the performance of infrared photodetectors. In this review, we review the progress of room-temperature infrared photodetectors with hybrid structure based on 2D materials in recent years, focusing mainly on 2D–nD(n = 0, 1, 2) heterostructures, the integration between 2D materials and on-chip or plasmonic structure. Finally, we summarize the current challenges and point out the future development direction.
文摘The characterization of microstructure for three kinds of typical low dimensional materials,such as ultrafine particle(zero- dimension),whisker(one- dimension)and thin film(two-dimensions),has been carried out.The methods and criteria for the characterization are investigated and introduced.Some interesting results of the characterization are reported.
文摘This paper,based on the New Curriculum Standards,researched the content of the curriculum for the newly edited material for High school English and gave suggestion on material adaptation for both curriculum designers and classroom teachers.
基金Funded by National High-tech Research and Development Projects of China(No. 2002AA6Z3083)
文摘An ultraviolet（UV） curable support material pre-polymer for three dimensional printing was prepared based on the synergistic effect between PEO-PPO-PEO tri-block copolymer（F127） and polyethylene glycol （400） di-acrylate（SR344）. The effects of jetting conditions, thermal stability, curing time, mechanical properties and shrinking rate on printing models were studied. The situation of removing support material from build model was investigated after building progress was completed. The experimental result shows that when F127 is 6.0wt%, SR344 is 20.0wt%, 4-Methoxy phenol is 0.15wt% and Irgacure 2959 is 1.5wt%, the support material pre-polymer could be jetted out from the nozzles smoothly during building up of three dimensional printing models at 50-55 ℃. In addition, the support material could be removed easily from building model without spoiling the model; furthermore, the forming precision of building model is improved.
基金the financial support from the 973 Programs of China(2013CBA01602)NSFC for Excellent Youth Scholars(51722304)+4 种基金NSFC(21720102002,21574080 and 61306018)Shanghai Committee of Science and Technology(15JC1490500,16JC1400703)and Open Project Program of the State Key Laboratory of Supramolecular Structure and Materials(sklssm201732,Jilin University)State Key Laboratory of Inorganic Synthesis and Preparative Chemistry(2016-08,Jilin University)State Key Laboratory for Mechanical Behavior of Materials(20161803,Xi’an Jiaotong University)
文摘With the increasing demand for large-scale battery systems in electric vehicles（EVs） and smart renewable energy grids, organic materials including small molecules and polymers utilized as electrodes in rechargeable batteries have received increasing attraction. In recent years, two-dimensional（2D） organic materials possessing planar layered architecture exhibit optional chemical modification, high specific surface area as well as unique electrical/magnetic properties, which have been emerging as the promising functional materials for wide applications in optoelectronics, catalysis, sensing, etc. Integrating with high-density redox-active sites and hierarchical porous structure, significant achievements in 2D organic materials as cathode materials for alkali-metal-ion batteries have been witnessed. In this review, the recent progress in synthetic approaches, structure analyses, electrochemical characterizations of 2D organic materials as well as their application in alkali-metal-ion batteries containing lithium ion battery（LIB）, lithium sulfur battery（LSB）, lithium air battery（LAB） and sodium ion battery（SIB） are summarized systematically,and their current challenges including cycling stability and electron conductivity for cathode materials in battery fields are also discussed.
基金Supported by Natural Sciences and Engineering Research Council of Canada, Alberta Energy Research Institute and the Department of Civil Engineering at University of Calgary
文摘Grain crushing plays an important role in one-dimensional (1D) compression and creep behaviors of granular materials under high stress. It is clear that the macro-properties of granular materials are closely related to the micro-fracture properties of grains in 1D compression and creep tests. In this paper, a series of 1D compression and creep tests were performed on Ottawa sand to investigate the deformation and grain crushing properties of granular materials, and it shows that the void ratio is correlated to the grain crushing amount (the quantity of crushed grains) for granular materials subjected to grain crushing. The test results, combining with the existing test data related to grain crushing of granular materials, were used to verify the relation. Moreover, the implications of these relations on the yield of granular material, and the equivalent effect of stress and time in changing soil fabric are presented.
