The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various field...The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various fields,such as catalysis,energy storage,sensing,etc.In recent years,a lot of research work on TMDs based functional materials in the fields of electromagnetic wave absorption(EMA)has been carried out.Therefore,it is of great significance to elaborate the influence of TMDs on EMA in time to speed up the application.In this review,recent advances in the development of electromagnetic wave(EMW)absorbers based on TMDs,ranging from the VIB group to the VB group are summarized.Their compositions,microstructures,electronic properties,and synthesis methods are presented in detail.Particularly,the modulation of structure engineering from the aspects of heterostructures,defects,morphologies and phases are systematically summarized,focusing on optimizing impedance matching and increasing dielectric and magnetic losses in the EMA materials with tunable EMW absorption performance.Milestones as well as the challenges are also identified to guide the design of new TMDs based dielectric EMA materials with high performance.展开更多
The Janus monolayer transition metal dichalcogenides(TMDs)MXY(M=Mo,W,etc.and X,Y=S,Se,etc.)have been successfully synthesized in recent years.The Rashba spin splitting in these compounds arises due to the breaking of ...The Janus monolayer transition metal dichalcogenides(TMDs)MXY(M=Mo,W,etc.and X,Y=S,Se,etc.)have been successfully synthesized in recent years.The Rashba spin splitting in these compounds arises due to the breaking of out-of-plane mirror symmetry.Here we study the pairing symmetry of superconducting Janus monolayer TMDs within the weak-coupling framework near critical temperature Tc,of which the Fermi surface(FS)sheets centered around bothΓand K(K′)points.We find that the strong Rashba splitting produces two kinds of topological superconducting states which differ from that in its parent compounds.More specifically,at relatively high chemical potentials,we obtain a timereversal invariant s+f+p-wave mixed superconducting state,which is fully gapped and topologically nontrivial,i.e.,a Z_(2) topological state.On the other hand,a time-reversal symmetry breaking d+p+f-wave superconducting state appears at lower chemical potentials.This state possess a large Chern number|C|=6 at appropriate pairing strength,demonstrating its nontrivial band topology.Our results suggest the Janus monolayer TMDs to be a promising candidate for the intrinsic helical and chiral topological superconductors.展开更多
The GaN-based heterostructures are widely used in optoelectronic devices,but the complex surface reconstructions and lattice mismatch greatly limit the applications.The stacking of two-dimensional transition metal dic...The GaN-based heterostructures are widely used in optoelectronic devices,but the complex surface reconstructions and lattice mismatch greatly limit the applications.The stacking of two-dimensional transition metal dichalcogenide(TMD=MoS_(2),MoSSe and MoSe_(2))monolayers on reconstructed GaN surface not only effectively overcomes the larger mismatch,but also brings about novel electronic and optical properties.By adopting the reconstructed GaN(0001)surface with adatoms(N-ter GaN and Ga-ter GaN),the influences of complicated surface conditions on the electronic properties of heterostructures have been investigated.The passivated N-ter and Ga-ter GaN surfaces push the mid-gap states to the valence bands,giving rise to small bandgaps in heterostructures.The charge transfer between Ga-ter GaN surface and TMD monolayers occurs much easier than that across the TMD/N-ter GaN interfaces,which induces stronger interfacial interaction and larger valence band offset(VBO).The band alignment can be switched between type-I and type-II by assembling different TMD monolayers,that is,MoS_(2)/N-ter GaN and MoS_(2)/Ga-ter GaN are type-II,and the others are type-I.The absorption of visible light is enhanced in all considered TMD/reconstructed GaN heterostructures.Additionally,MoSe_(2)/Ga-ter GaN and MoSSe/N-ter GaN have larger conductor band offset(CBO)of 1.32 eV and 1.29 eV,respectively,extending the range from deep ultraviolet to infrared regime.Our results revel that the TMD/reconstructed GaN heterostructures may be used for high-performance broadband photoelectronic devices.展开更多
Doping foreign metal atoms into the substrate of transition metal dichalcogenides(TMDs)enables the formation of diverse atomic structure configurations,including isolated atoms,chains,and clusters.Therefore,it is very...Doping foreign metal atoms into the substrate of transition metal dichalcogenides(TMDs)enables the formation of diverse atomic structure configurations,including isolated atoms,chains,and clusters.Therefore,it is very important to reasonably control the atomic structure and determine the structure-activity relationship between the atomic configurations and the hydrogen evolution reaction(HER)performance.Although numerous studies have indicated that doping can yield diverse atomic structure configurations,there remains an incomplete understanding of the relationship between atomic configurations within the lattice of TMDs and their performance.Here,diverse atomic structure configurations of adsorptive doping,substitutional doping,and TMDs alloys are summarized.The structure-activity relationship between different atomic configurations and HER performance can be determined by micro-nanostructure devices and density functional theory(DFT)calculations.These diverse atomic structure configurations are of great significance for activating the inert basal plane of TMDs and improving the catalytic activity of HER.Finally,we have summarized the current challenges and future opportunities,offering new perspectives for the design of highly active and stable metal-doped TMDs catalysts.展开更多
Due to the growing resistance of available drugs to bacterial infection and the slow development of antibiotics,there is a continuous need to design and develop new antibacterial agents.The interest to develop transit...Due to the growing resistance of available drugs to bacterial infection and the slow development of antibiotics,there is a continuous need to design and develop new antibacterial agents.The interest to develop transition metal dichalcogenides(TMDs)based antibacterial agents has significantly increased in recent years.This research interest is driven by their interesting properties such as metallic and semiconducting nature of different phases,electronic confinement,large surface to volume ratio,the possibility of surface functionalization,and their potential application as a material in biomedical sciences.Different synthetic strategies have been developed to synthesize monolayered TMDs and their functionalization with different bioactive molecules.Researchers have given a lot of effort to establish the structure-activity correlation between different TMDs and their antibacterial activity.Here,we have reviewed various exfoliation strategies for TMDs,different methods for their functionalization,and the antibacterial activity of different TMDs.展开更多
Two-dimensional(2D)transition metal dichalcogenides(TMDs)with fascinating electronic energy band structures,rich valley physical properties and strong spin–orbit coupling have attracted tremendous interest,and show g...Two-dimensional(2D)transition metal dichalcogenides(TMDs)with fascinating electronic energy band structures,rich valley physical properties and strong spin–orbit coupling have attracted tremendous interest,and show great potential in electronic,optoelectronic,spintronic and valleytronic fields.Stacking 2D TMDs have provided unprecedented opportunities for constructing artificial functional structures.Due to the low cost,high yield and industrial compatibility,chemical vapor deposition(CVD)is regarded as one of the most promising growth strategies to obtain high-quality and large-area 2D TMDs and heterostructures.Here,state-of-the-art strategies for preparing TMDs details of growth control and related heterostructures construction via CVD method are reviewed and discussed,including wafer-scale synthesis,phase transition,doping,alloy and stacking engineering.Meanwhile,recent progress on the application of multi-functional devices is highlighted based on 2D TMDs.Finally,challenges and prospects are proposed for the practical device applications of 2D TMDs.展开更多
Fundamental understandings on the dynamics of charge carriers and excitonic quasiparticles in semiconductors are of central importance for both many-body physics and promising optoelectronic and photonic applications....Fundamental understandings on the dynamics of charge carriers and excitonic quasiparticles in semiconductors are of central importance for both many-body physics and promising optoelectronic and photonic applications.Here,we investigated the carrier dynamics and many-body interactions in two-dimensional(2D)transition metal dichalcogenides(TMDs),using monolayer WS2 as an example,by employing femtosecond broadband pump-probe spectroscopy.Three time regimes for the exciton energy renormalization are unambiguously revealed with a distinct red-blue-red shift upon above-bandgap optical excitations.We attribute the dominant physical process in the three typical regimes to free carrier screening effect,Coulombic exciton-exciton interactions and Auger photocarrier generation,respectively,which show distinct dependence on the optical excitation wavelength,pump fluences and/or lattice temperature.An intrinsic exciton radiative lifetime of about 1.2 picoseconds(ps)in monolayer WS2 is unraveled at low temperature,and surprisingly the efficient Auger nonradiative decay of both bright and dark excitons puts the system in a nonequilibrium state at the nanosecond timescale.In addition,the dynamics of trions at low temperature is observed to be significantly different from that of excitons,e.g.,a long radiative lifetime of^108.7 ps at low excitation densities and the evolution of trion energy as a function of delay times.Our findings elucidate the dynamics of excitonic quasiparticles and the intricate many-body physics in 2D semiconductors,underpinning the future development of photonics,valleytronics and optoelectronics based on 2D semiconductors.展开更多
Grain boundary(GB),as a kind of lattice defect,widely exists in two-dimensional transition metal dichalcogenides(2D TMDs),which has complex and diverse influences on the physical/chemical properties of 2D TMDs.GBs are...Grain boundary(GB),as a kind of lattice defect,widely exists in two-dimensional transition metal dichalcogenides(2D TMDs),which has complex and diverse influences on the physical/chemical properties of 2D TMDs.GBs are universally considered to be a double-edged sword,although some electrical and mechanical properties of 2D TMDs would be adversely affected leading to the reduced overall quality,certain structure-oriented applications could be realized based on its unique properties.In this review,we first detailed the atomic structure characteristics of GBs and the corresponding techniques,then we systematically summarized the methods of introducing GBs into 2D TMDs.Next,we expounded unique electrical,mechanical,and chemical properties of the GBs in 2D TMDs and clarified its internal relationship with the atomic structure.Moreover,the application of GB structure in hydrogen evolution reaction(HER)is also discussed.In the end,we make a conclusion and put forward outlooks,hoping to further promote the basic research of GB and boost the wide application of 2D TMDs.展开更多
基金This work was supported by the National Natural Science Foundation of China(52372289,52102368,52072192 and 51977009)Regional Joint Fund for Basic Research and Applied Basic Research of Guangdong Province(No.2020SA001515110905).
文摘The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various fields,such as catalysis,energy storage,sensing,etc.In recent years,a lot of research work on TMDs based functional materials in the fields of electromagnetic wave absorption(EMA)has been carried out.Therefore,it is of great significance to elaborate the influence of TMDs on EMA in time to speed up the application.In this review,recent advances in the development of electromagnetic wave(EMW)absorbers based on TMDs,ranging from the VIB group to the VB group are summarized.Their compositions,microstructures,electronic properties,and synthesis methods are presented in detail.Particularly,the modulation of structure engineering from the aspects of heterostructures,defects,morphologies and phases are systematically summarized,focusing on optimizing impedance matching and increasing dielectric and magnetic losses in the EMA materials with tunable EMW absorption performance.Milestones as well as the challenges are also identified to guide the design of new TMDs based dielectric EMA materials with high performance.
基金Project supported by the National Natural Science Foundation of China(Grant No.11904155)。
文摘The Janus monolayer transition metal dichalcogenides(TMDs)MXY(M=Mo,W,etc.and X,Y=S,Se,etc.)have been successfully synthesized in recent years.The Rashba spin splitting in these compounds arises due to the breaking of out-of-plane mirror symmetry.Here we study the pairing symmetry of superconducting Janus monolayer TMDs within the weak-coupling framework near critical temperature Tc,of which the Fermi surface(FS)sheets centered around bothΓand K(K′)points.We find that the strong Rashba splitting produces two kinds of topological superconducting states which differ from that in its parent compounds.More specifically,at relatively high chemical potentials,we obtain a timereversal invariant s+f+p-wave mixed superconducting state,which is fully gapped and topologically nontrivial,i.e.,a Z_(2) topological state.On the other hand,a time-reversal symmetry breaking d+p+f-wave superconducting state appears at lower chemical potentials.This state possess a large Chern number|C|=6 at appropriate pairing strength,demonstrating its nontrivial band topology.Our results suggest the Janus monolayer TMDs to be a promising candidate for the intrinsic helical and chiral topological superconductors.
基金Project supported by the Science Challenge Project(Grant No.TZ2018004)the Natural Science Basic Research Program of Shaanxi Province,China(Grant No.2021JQ-697)+2 种基金the National Natural Science Foundation of China(Grant Nos.11874097,91961204,and 12004303)XinLiaoYingCai Project of Liaoning Province,China(Grant No.XLYC1905014)Key Research and Development Project of Liaoning Province,China(Grant No.2020JH2/10500003)。
文摘The GaN-based heterostructures are widely used in optoelectronic devices,but the complex surface reconstructions and lattice mismatch greatly limit the applications.The stacking of two-dimensional transition metal dichalcogenide(TMD=MoS_(2),MoSSe and MoSe_(2))monolayers on reconstructed GaN surface not only effectively overcomes the larger mismatch,but also brings about novel electronic and optical properties.By adopting the reconstructed GaN(0001)surface with adatoms(N-ter GaN and Ga-ter GaN),the influences of complicated surface conditions on the electronic properties of heterostructures have been investigated.The passivated N-ter and Ga-ter GaN surfaces push the mid-gap states to the valence bands,giving rise to small bandgaps in heterostructures.The charge transfer between Ga-ter GaN surface and TMD monolayers occurs much easier than that across the TMD/N-ter GaN interfaces,which induces stronger interfacial interaction and larger valence band offset(VBO).The band alignment can be switched between type-I and type-II by assembling different TMD monolayers,that is,MoS_(2)/N-ter GaN and MoS_(2)/Ga-ter GaN are type-II,and the others are type-I.The absorption of visible light is enhanced in all considered TMD/reconstructed GaN heterostructures.Additionally,MoSe_(2)/Ga-ter GaN and MoSSe/N-ter GaN have larger conductor band offset(CBO)of 1.32 eV and 1.29 eV,respectively,extending the range from deep ultraviolet to infrared regime.Our results revel that the TMD/reconstructed GaN heterostructures may be used for high-performance broadband photoelectronic devices.
基金supported by the Natural Science Foundation of China(No.51902101)the Natural Science Foundation of Jiangsu Province(No.BK20201381)+1 种基金the Science Foundation of Nanjing University of Posts and Telecommunications(Nos.NY219144,NY221046)the National College Student Innovation and Entrepreneurship Training Program(No.202210293171K).
文摘Doping foreign metal atoms into the substrate of transition metal dichalcogenides(TMDs)enables the formation of diverse atomic structure configurations,including isolated atoms,chains,and clusters.Therefore,it is very important to reasonably control the atomic structure and determine the structure-activity relationship between the atomic configurations and the hydrogen evolution reaction(HER)performance.Although numerous studies have indicated that doping can yield diverse atomic structure configurations,there remains an incomplete understanding of the relationship between atomic configurations within the lattice of TMDs and their performance.Here,diverse atomic structure configurations of adsorptive doping,substitutional doping,and TMDs alloys are summarized.The structure-activity relationship between different atomic configurations and HER performance can be determined by micro-nanostructure devices and density functional theory(DFT)calculations.These diverse atomic structure configurations are of great significance for activating the inert basal plane of TMDs and improving the catalytic activity of HER.Finally,we have summarized the current challenges and future opportunities,offering new perspectives for the design of highly active and stable metal-doped TMDs catalysts.
基金DST-SERB (CVD/2020/000855) for financial support。
文摘Due to the growing resistance of available drugs to bacterial infection and the slow development of antibiotics,there is a continuous need to design and develop new antibacterial agents.The interest to develop transition metal dichalcogenides(TMDs)based antibacterial agents has significantly increased in recent years.This research interest is driven by their interesting properties such as metallic and semiconducting nature of different phases,electronic confinement,large surface to volume ratio,the possibility of surface functionalization,and their potential application as a material in biomedical sciences.Different synthetic strategies have been developed to synthesize monolayered TMDs and their functionalization with different bioactive molecules.Researchers have given a lot of effort to establish the structure-activity correlation between different TMDs and their antibacterial activity.Here,we have reviewed various exfoliation strategies for TMDs,different methods for their functionalization,and the antibacterial activity of different TMDs.
基金supported by the National Key R&D Program of China(No.2018YFA0703700,J.H.)the National Natural Science Foundation of China(Nos.91964203,J.H.,62004142,Y.W.,62134001,62104171,R.C.,62104172,L.Y.,62174122,Y.G.and 11774269,S.Y.)+3 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB44000000,J.H.)the Natural Science Foundation of Hubei Province,China(Nos.2021CFB037,R.C.and 2020CFA041,S.Y.)the Fundamental Research Funds for the Central Universities(No.2042021kf0067,R.C.)the Special Fund of Hubei Luojia Laboratory.
文摘Two-dimensional(2D)transition metal dichalcogenides(TMDs)with fascinating electronic energy band structures,rich valley physical properties and strong spin–orbit coupling have attracted tremendous interest,and show great potential in electronic,optoelectronic,spintronic and valleytronic fields.Stacking 2D TMDs have provided unprecedented opportunities for constructing artificial functional structures.Due to the low cost,high yield and industrial compatibility,chemical vapor deposition(CVD)is regarded as one of the most promising growth strategies to obtain high-quality and large-area 2D TMDs and heterostructures.Here,state-of-the-art strategies for preparing TMDs details of growth control and related heterostructures construction via CVD method are reviewed and discussed,including wafer-scale synthesis,phase transition,doping,alloy and stacking engineering.Meanwhile,recent progress on the application of multi-functional devices is highlighted based on 2D TMDs.Finally,challenges and prospects are proposed for the practical device applications of 2D TMDs.
基金Supported by the National Natural Science Foundation of China(11991063,62004207,61725505,62104118)the Shanghai Science and Technology Committee(2019SHZDZX01,19XD1404100,20YF1455900,20ZR1474000)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(XDB43010200)the Youth Innovation Promotion Association CAS(2018276)。
基金Q.H.X.gratefully acknowledges the support from Singapore Ministry of Education via AcRF Tier 3 Programme(No.MOE2018-T3-1-002)Tier 2 project(No.MOE2017-T2-1-040)Singapore National Research Foundation via NRF-ANR project(No.NRF2017-NRF-ANR0052D-Chiral).
文摘Fundamental understandings on the dynamics of charge carriers and excitonic quasiparticles in semiconductors are of central importance for both many-body physics and promising optoelectronic and photonic applications.Here,we investigated the carrier dynamics and many-body interactions in two-dimensional(2D)transition metal dichalcogenides(TMDs),using monolayer WS2 as an example,by employing femtosecond broadband pump-probe spectroscopy.Three time regimes for the exciton energy renormalization are unambiguously revealed with a distinct red-blue-red shift upon above-bandgap optical excitations.We attribute the dominant physical process in the three typical regimes to free carrier screening effect,Coulombic exciton-exciton interactions and Auger photocarrier generation,respectively,which show distinct dependence on the optical excitation wavelength,pump fluences and/or lattice temperature.An intrinsic exciton radiative lifetime of about 1.2 picoseconds(ps)in monolayer WS2 is unraveled at low temperature,and surprisingly the efficient Auger nonradiative decay of both bright and dark excitons puts the system in a nonequilibrium state at the nanosecond timescale.In addition,the dynamics of trions at low temperature is observed to be significantly different from that of excitons,e.g.,a long radiative lifetime of^108.7 ps at low excitation densities and the evolution of trion energy as a function of delay times.Our findings elucidate the dynamics of excitonic quasiparticles and the intricate many-body physics in 2D semiconductors,underpinning the future development of photonics,valleytronics and optoelectronics based on 2D semiconductors.
基金financially supported by the Natural Science Foundation of China(No.51902101)Natural Science Foundation of Jiangsu Province(No.BK20201381)+1 种基金Science Foundation of Nanjing University of Posts and Telecommunications(No.NY219144)the National College Student Innovation and Entrepreneurship Training Program(No.202210293171K).
文摘Grain boundary(GB),as a kind of lattice defect,widely exists in two-dimensional transition metal dichalcogenides(2D TMDs),which has complex and diverse influences on the physical/chemical properties of 2D TMDs.GBs are universally considered to be a double-edged sword,although some electrical and mechanical properties of 2D TMDs would be adversely affected leading to the reduced overall quality,certain structure-oriented applications could be realized based on its unique properties.In this review,we first detailed the atomic structure characteristics of GBs and the corresponding techniques,then we systematically summarized the methods of introducing GBs into 2D TMDs.Next,we expounded unique electrical,mechanical,and chemical properties of the GBs in 2D TMDs and clarified its internal relationship with the atomic structure.Moreover,the application of GB structure in hydrogen evolution reaction(HER)is also discussed.In the end,we make a conclusion and put forward outlooks,hoping to further promote the basic research of GB and boost the wide application of 2D TMDs.
