Two-dimensional/one-dimensional(2D/1D)heterostructures as a new type of heterostructure have been studied for their unusual properties and promising applications in electronic and optoelectronic devices.However,the st...Two-dimensional/one-dimensional(2D/1D)heterostructures as a new type of heterostructure have been studied for their unusual properties and promising applications in electronic and optoelectronic devices.However,the studies of 2D/1D heterostructures are mainly focused on vertical heterostructures,such as MoS_(2) nanosheet-carbon nanotubes.The research on lateral 2D/1D heterostructures with a tunable width of 1D material is still scarce.In this study,bidirectional flow chemical vapor deposition(CVD)was used to accurately control the width of the WS_(2)/WSe2(WS_(2)/MoS_(2))heterostructures by controlling reacting time.WSe2 and MoS_(2) with different widths were epitaxially grown at the edge of WS_(2),respectively.Optical microscope,atomic force microscope(AFM),and scanning electron microscope(SEM)images show the morphology and width of the heterostructures.These results show that the width of the heterostructures can be as low as 10 nm by using this method.The interface of the heterostructure is clear and smooth,which is suitable for application.This report offers a new method for the growth of 1D nanowires,and lays the foundation for the future study of the physical and chemical properties of 2D/1D lateral heterostructures.展开更多
Two-dimensional(2D)materials,especially 2D transition metal oxides(TMOs),have garnered significant research attention due to their unique physical and chemical properties and vast potential applications in electronics...Two-dimensional(2D)materials,especially 2D transition metal oxides(TMOs),have garnered significant research attention due to their unique physical and chemical properties and vast potential applications in electronics,optoelectronics,magneto electronics,and energy storage.However,synthesizing 2D TMOs remains a major challenge due to their non-layered lattice structure and the high temperatures required for synthesis.In this study,we report the chemical vapor deposition-based synthesis of high-quality 2D Cr_(2)O_(3) single-crystal nanosheets and investigate their structure and electrical properties.By controlling the growth temperature and carrier gas,we successfully obtained Cr_(2)O_(3) nanosheets with lateral dimensions up to 30μm and a minimum thickness of 4.7 nm.Optical studies,X-ray diffraction,atomic force microscopy,and transmission electron microscopy confirm that the resulting nanosheets are high-quality single crystals.Electrical measurements reveal that charge transport in Cr_(2)O_(3) devices is influenced by both Schottky emission and Poole-Frenkel emission,leading to a non-equilibrium charge conduction state.This systematic synthesis approach provides a reliable route for fabricating 2D TMO single crystals with controlled thickness and offers a platform for investigating charge transfer at electrode-dielectric interfaces,as well as for the design of novel electronic materials and catalysts.展开更多
Earth-abundant electrocatalysts for large-current-density water splitting under alkaline condition are desirable.Oxygen evolution reaction,which is a bottleneck of the overall water splitting,faces the problems of com...Earth-abundant electrocatalysts for large-current-density water splitting under alkaline condition are desirable.Oxygen evolution reaction,which is a bottleneck of the overall water splitting,faces the problems of complicated reconstruction and deficiency in rational design of active sites.Herein,we report a series of transition metal chalcogenides for alkaline OER.Among them,FeCoNi(S)displayed a low overpotential of 293 m V to deliver a current density of 500 m A cm^(-2),which is in the top level of non-precious metal based OER electrocatalysts.A combination of(ex)in situ characterizations and DFT calculation shows that Ni(Fe,Co)trimetallic oxyhydroxides were the active sites for highly-efficient OER.Furthermore,for FeCoNi(S),when used as a bifunctional catalyst for water splitting,it only required a cell voltage of 1.84 V to deliver~500 m A cm^(-2) with extraordinary long-term stability over 2000 h.This work provides the comprehension of high-efficiency,robust catalysts for OER and overall water splitting at large current densities in alkaline media.展开更多
Black phosphorus （BP）, an attractive two-dimensional （2D） semiconductor, is widely used in the fields of optoelec- tronic devices, biomedicine, and chemical sensing. Silver ion （Ag＋）, a commonly used additive i...Black phosphorus （BP）, an attractive two-dimensional （2D） semiconductor, is widely used in the fields of optoelec- tronic devices, biomedicine, and chemical sensing. Silver ion （Ag＋）, a commonly used additive in food industry, can sterilize and keep food fresh. But excessive intake of Ag＋ will harm human health. Therefore, high sensitive, fast and simple Ag＋ detection method is significant. Here, a high-performance BP field effect transistor （FET） sensor is fabricated for Ag＋ detection with high sensitivity, rapid detection speed, and wide detection concentration range. The detection limit for Ag＋ is 10 l0 mol/L. Testing time for each sample by this method is 60 s. Besides, the mechanism of BP-FET sensor for Ag＋ detection is investigated systematically. The simple BP-FET sensor may inspire some relevant research and potential applications, such as providing an effective method for the actual detection of Ag＋, especially in wimessed inspections field of food.展开更多
Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)converts CO_(2)into valuable chemical fuels,which can effectively alleviate global warming and energy crisis.However,limited by its slow reaction rate and low product...Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)converts CO_(2)into valuable chemical fuels,which can effectively alleviate global warming and energy crisis.However,limited by its slow reaction rate and low product selectivity,it is urgent to design efficient,cheap,safe,and highly selective CO_(2)RR electrocatalysts.Owing to the advantages of adjustable electronic structure,abundant active sites,low cost,environmental friendliness and excellent electrochemical performance,bimetallic chalcogenides have aroused great interest.Here,we briefly summarized different bimetallic oxides and sulfides for electrocatalytic CO_(2)RR in the past five years.In addition,different hybridizations formed between metal atoms,including intermetallic compounds,heterostructures and metal doping,were generalized.Their positive effects on CO_(2)RR catalytic selectivity and activity were deeply uncovered.Besides,we also put forward some views about the future research directions and perspectives in CO_(2)RR field.This review aims to provide a reference for the rational design of bimetallic chalcogenides towards electrocatalytic CO_(2)reduction.展开更多
Lithium metal is one of the most promising anode materials for next-generation electrochemical energy storage due to low electrochemical potential and high specific capacity.However,large volume change and uncontrolla...Lithium metal is one of the most promising anode materials for next-generation electrochemical energy storage due to low electrochemical potential and high specific capacity.However,large volume change and uncontrollable formation of lithium dendrite during cycling severely hinder the practical application of rechargeable Li metal batteries.Herein,we report a hierarchically porous Cu covered with lithiophilic CuxO(HPCu-CuxO) via femtosecond laser strategy in about 2 min as current collector for highperformance Li metal batteries.With precisely tunable pore volume and depth as well as lithiophilic CuxO interphase,the HPCu-CuxO not only guides homogeneous Li nucleation,resulting in a smooth and dendrite-free lithium surface,but also provides space to alleviate the volume expansion of Li metal anode,achieving excellent structure stability.Consequently,highly stable Coulombic efficiency and ultralow overpotential of 15 mV even up to 1000 h were achieved at the current density of 1 mA cm^(-2).Moreover,the resultant Li@HPCu-CuxO//LiFePO_(4) full battery delivered outstanding cycle stability and rate capability.These results offer a pathway toward high-energy-density and safe rechargeable Li metal batteries.展开更多
Palladium diselenide(PdSe2),a stable layered material with pentagonal structure,has attracted extensive interest due to its excellent electrical and optoelectronic performance.Here,we report a reliable process to synt...Palladium diselenide(PdSe2),a stable layered material with pentagonal structure,has attracted extensive interest due to its excellent electrical and optoelectronic performance.Here,we report a reliable process to synthesize PdSe2 via chemical vapor deposition(CVD)method.Through systematic regulation of temperature in the growth process,we can tune the thickness,size,nucleation density and morphology of PdSe2 nanosheets.Field-effect transistors based on PdSe2 nanosheets exhibit n-type behavior and present a high electron mobility of 105 cm^2·V^−1·s^−1.The electrical property of the devices after 6 months keeping in the air show little change,implying outstanding air-stability of PdSe2.In addition,PdSe2 near-infrared photodetector shows a photoresponsivity of 660 A·W^−1 under 914 nm laser.These performances are better than those of most CVD-grown 2D materials,making ultrathin PdSe2 a highly qualified candidate material for next-generation optoelectronic applications.展开更多
Lithium-ion batteries (LIBs) have exhibited extraordinary prospects due to their high energy and power density.However, the future development of LIBs is largely impeded by poor rate performance and cycling stability ...Lithium-ion batteries (LIBs) have exhibited extraordinary prospects due to their high energy and power density.However, the future development of LIBs is largely impeded by poor rate performance and cycling stability of the graphite anode. Here, we demonstrate a practical niobium pentoxide and graphite (Nb_(2)O_(5)/G) hybrid anode for high-performance LIBs via the scalable high-energy ball milling method.展开更多
Narrow-bandgap materials possess the intriguing optical-electric properties and unique structures,which can be widely applied in the field of photonics,energy optoelectronic sensing and biomedicine,etc.Nowadays,the re...Narrow-bandgap materials possess the intriguing optical-electric properties and unique structures,which can be widely applied in the field of photonics,energy optoelectronic sensing and biomedicine,etc.Nowadays,the researches on nonlinear optical properties of narrow-bandgap materials have attracted extensive attention worldwide.In this paper,we review the progress of narrow-bandgap materials from many aspects,such as background,nonlinear optical properties,energy band structure,methods of preparation,and applications.These materials have obvious nonlinear optical characteristics and the interaction with the short pulse laser excitation shows the extremely strong nonlinear absorption characteristics,which leads to the optical limiting or saturable absorption related to Pauli blocking and excited state absorption.Especially,some of these novel narrow-bandgap materials have been utilized for the generation of ultrashort pulse that covers the range from the visible to mid-infrared wavelength regions.Hence,the study on these materials paves a new way for the advancement of optoelctronics devices.展开更多
Lithium metal is considered a desirable anode for the nextgeneration high-energy-density rechargeable energy storage devices.Unfortunately,poor lifespan and safety issues caused by unexpected dendrites growth have pre...Lithium metal is considered a desirable anode for the nextgeneration high-energy-density rechargeable energy storage devices.Unfortunately,poor lifespan and safety issues caused by unexpected dendrites growth have prevented the commercialization of Li metal anode.展开更多
Lithium metal has gained extensive attention as the most ideal candidate for next-generation battery anode owing to the ultrahigh specific capacity and the lowest electrochemical potential.However,uncontrollable dendr...Lithium metal has gained extensive attention as the most ideal candidate for next-generation battery anode owing to the ultrahigh specific capacity and the lowest electrochemical potential.However,uncontrollable dendrite growth and huge volume variation extremely restrict the future deployment of lithium metal batteries.Herein,we report metal chalcogenide SnSSe with unique nanoplate stacking structure as a robust substrate for stable Li metal anode.During the initial Li plating process,lithiophilic Li_(22)Sn_(5) alloy and Li_(2)S/Li_(2)Se sites are obtained via in-situ electrochemical reaction of Li metal and SnSSe.Density functional theory(DFT)calculation demonstrates that the formed Li_(2)S/Li_(2)Se achieves low Li diffusion energy barrier,ensuring rapid Li~+migration.Li_(22)Sn_(5) alloy provides strong nucleation sites,promoting uniform Li nucleation.Furthermore,in-situ optical microscopy analysis suggests that the synthesized effect fundamentally inhibits lithium dendrite growth.Consequently,SnSSe modified Cu foil delivered an ultralow nucleation overpotential,superior cycling stability with 450 cycles(Coulombic efficiency,>98%),and excellent plating/stripping behavior over 2200 h at 0.5 mA cm^(-2).Moreover,the brilliant reversible cycles and rate capability were also realized in Li@SnSSe//LiFePO_(4)(LFP)full cell,shedding light on the feasibility of SnSSe for stable and dendrite-free lithium metal anode.展开更多
Two-dimensional(2D)transition metal dichalcogenides(TMDs)have garnered widespread interest in the scientific community and industry for their exceptional physical and chemistry properties,and great potential for appli...Two-dimensional(2D)transition metal dichalcogenides(TMDs)have garnered widespread interest in the scientific community and industry for their exceptional physical and chemistry properties,and great potential for applications in diverse fields including(opto)electronics,electrocatalysis,and energy storage.Chemical vapor deposition(CVD)is one of the most compelling growth methods for the scalable growth of high-quality 2D TMDs.However,the conventional CVD process for synthesis of 2D TMDs still encounters significant challenges,primarily attributed to the high melting point of precursor powders,and achieving a uniform distribution of precursor atmosphere on the substrate to obtain controllable smaple domains is difficult.The spin-coating precursor mediated chemical vapor deposition(SCVD)strategy provides refinement over traditional methods by eliminating the use of solid precursors and ensuring a more clean and uniform distribution of the growth material on the substrate.Additionally,the SCVD process allows fine-tuning of material thickness and purity by manipulating solution composition,concentration,and the spin coating process.This Review presents a comprehensive summary of recent advances in controllable growth of 2D TMDs with a SCVD strategy.First,a series of various liquid precursors,additives,source supply methods,and substrate engineering strategies for preparing atomically thin TMDs by SCVD are introduced.Then,2D TMDs heterostructures and novel doped TMDs fabricated through the SCVD method are discussed.Finally,the current challenges and perspectives to synthesize 2D TMDs using SCVD are discussed.展开更多
Two-dimensional(2D)magnetic materials have aroused tremendous interest due to the 2D confinement of magnetism and potential applications in spintronic and valleytronic devices.However,most of the currently 2D magnetic...Two-dimensional(2D)magnetic materials have aroused tremendous interest due to the 2D confinement of magnetism and potential applications in spintronic and valleytronic devices.However,most of the currently 2D magnetic materials are achieved by the exfoliation from their bulks,of which the thickness and domain size are difficult to control,limiting the practical device applications.Here,we demonstrate the realization of thickness-tunable rhombohedral Cr_(2)Se_(3)nanosheets on different substrates via the chemical vapor deposition route.The magnetic transition temperature at about 75 K is observed.Furthermore,van der Waals heterostructures consisting of Cr_(2)Se_(3)nanosheets and monolayer WS2 are constructed.We observe the magnetic proximity effect in the heterostructures,which manifests the manipulation of the valley polarization in monolayer WS2.Our work contributes to the vapor growth and applications of 2D magnetic materials.展开更多
CONSPECTUS:Two-dimensional(2D)heterostructures have created many novel properties and triggered a variety of promising applications,thus setting off a boom in the modern semiconductor industry.As the first road to ste...CONSPECTUS:Two-dimensional(2D)heterostructures have created many novel properties and triggered a variety of promising applications,thus setting off a boom in the modern semiconductor industry.As the first road to step into adequately exploring the properties and real applications,the material preparation process matters a lot.Adhering to the concept of epitaxial growth,chemical vapor deposition(CVD)shows great potential for the preparation of heterostructures for commercialization.展开更多
The controllable synthesis of complicated nanostructures in advanced two-dimensional(2D)semiconductors,such as periodic regular hole arrays,is essential and remains immature.Here,we report a green,facile,highly contro...The controllable synthesis of complicated nanostructures in advanced two-dimensional(2D)semiconductors,such as periodic regular hole arrays,is essential and remains immature.Here,we report a green,facile,highly controlled synthetic method to efficiently pattern 2D semiconductors,such as periodic regular hexagonal-shaped hole arrays(HHA),in 2D-TMDs.Combining the production of artificial defect arrays through laser irradiation with anisotropic annealing etching,we created HHA with different arrangements,controlled hole sizes,and densities in bilayer WS_(2).Atomic force microscopy(AFM),Raman,photoluminescence(PL),and scanning transmission electron microscopy(STEM)characterization show that the 2D semiconductors have high quality with atomical clean and sharp edges as well as undamaged crystals in the unetched region.Furthermore,other nanostructures,such as nanoribbons and periodic regular triangular-shaped 2D-TMD arrays,can be fabricated.This kind of 2D semiconductors fabrication strategy is general and can be extended to a series of 2D materials.Density functional theory(DFT)calculations show that one WS_(2)molecule from the edges of the laser-irradiated holed region exhibits a robust etching activation,making selective etching at the artificial defects and the fabrication of regular 2D semiconductors possible.展开更多
A magnetic semiconductor whose electronic charge and spin can be regulated together will be an important compon-ent of future spintronic devices.Here,we construct a two-dimensional(2D)Fe doped SnS_(2)(Fe-SnS_(2))homog...A magnetic semiconductor whose electronic charge and spin can be regulated together will be an important compon-ent of future spintronic devices.Here,we construct a two-dimensional(2D)Fe doped SnS_(2)(Fe-SnS_(2))homogeneous junction and investigate its electromagnetic transport feature.The Fe-SnS_(2) homojunction device showed large positive and unsatur-ated magnetoresistance(MR)of 1800%in the parallel magnetic field and 600%in the vertical magnetic field,indicating an obvi-ous anisotropic MR feature.In contrast,The MR of Fe-SnS_(2) homojunction is much larger than the pure diamagnetic SnS_(2) and most 2D materials.The application of a gate voltage can regulate the MR effect of Fe-SnS_(2) homojunction devices.Moreover,the stability of Fe-SnS_(2) in air has great application potential.Our Fe-SnS_(2) homojunction has a significant potential in future mag-netic memory applications.展开更多
Large-scale synthesis of high-quality two dimensional(2D)semiconductors,such as molybdenum disulfide(MoS_(2)),is a prerequisite for their lab-to-fab transition.It is crucial to systematically explore and understand th...Large-scale synthesis of high-quality two dimensional(2D)semiconductors,such as molybdenum disulfide(MoS_(2)),is a prerequisite for their lab-to-fab transition.It is crucial to systematically explore and understand the influence of key synthetic conditions on the nucleation,uniformity,and quality of MoS_(2) wafers.Here,we report the epitaxial growth of high-quality and uniform monolayer MoS_(2) films on 2-in c-plane sapphire by chemical vapor deposition(CVD)method under optimized growth conditions(0–1 mg NaCl,adequate S/Mo ratio,and the addition of 0–1 sccm O2).We systematically explore the influence of critical synthetic conditions on the nucleation,and stitching of MoS_(2) domains over the wafer scale,including the dosage of the alkali metal salt NaCl additive,the evaporation temperature of MoO_(3),the distance between MoO_(3) and the substrate,and the flow rate of O_(2).Among them,the dosage of NaCl and the S/Mo ratio have important influences on the quality and film coverage of MoS_(2),while the flow rate of O_(2) plays a key role in controlling the nucleation density and domain size.We further discovered that a-plane sapphire could easily guide the unidirectional growth of MoS_(2) without the need for other specific synthetic conditions compared with c-plane and m-plane sapphire.The field-effect transistors(FETs)fabricated from the full-coverage films show an average and the highest mobilities of 28.5 and around 45 cm^(2)·V−1·s^(-1),respectively.展开更多
The design and application of single-atom catalysts have gained significant attention in photocatalysis.However,precisely and firmly anchoring single atoms on substrate surfaces remains a challenge.This study employs ...The design and application of single-atom catalysts have gained significant attention in photocatalysis.However,precisely and firmly anchoring single atoms on substrate surfaces remains a challenge.This study employs an innovative silane coupling agent grafting strategy to precisely and stably anchor Cu single-atoms on the substrate.Scanning ransmission lectron microscopy(STEM)and X-ray absorption fine structure spectroscopy(XAFS)confirm the successful loading of Cu single-atoms.Photoelectric tests show that the stable channel formed by the carbon chain effectively enhances carrier separation and transport efficiency between Cu and the substrate.Density functional theory(DFT)calculations indicate that the adsorption energy barrier of the intermediate product is reduced by 0.106 eV,improving the reaction kinetics.After grafting with the silane coupling agent,the performance of Cu single-atom-loaded materials is further enhanced by 12.16 times.The strong anchoring prevents Cu single-atom detachment and aggregation during photocatalysis,while excess charge carriers produced by Cu atoms are efficiently transferred to the substrate for reaction.Compared to traditional Cu single-atom supported catalysts,the grafted samples in this study demonstrate superior performance and stability in photocatalytic reduction reactions.This approach provides a reliable and innovative pathway for the directional and stable production of single-atom catalysts.展开更多
Phase transition and edge structure reconstruction of twodimensional(2D)materials are critical for modulating their properties and applications.Here,we employ a hydrogen-assisted annealing method to accomplish the ext...Phase transition and edge structure reconstruction of twodimensional(2D)materials are critical for modulating their properties and applications.Here,we employ a hydrogen-assisted annealing method to accomplish the extensive transformation from a 2H MoTe_(2)single crystal to Mo_(6)Te_(6)nanowires and quasi-2D Mo_(6)Te_(6)nanoribbons.Introducing hydrogen gas during atmospheric pressure annealing process generates a Te-poor chemical environment,which makes the transformations energetically favorable and is essential for the fast growth of Mo_(6)Te_(6)nanowires.Mo_(6)Te_(6)nanowires nucleate at the exposed edges of 2H MoTe_(2)and grow along its[1120],[2110],and[1210]crystallographic directions,demonstrating long-range order and forming quais-2D nanoribbons with lengths up to 50μm.Finally,nanoribbons align in sixfold oriented directions and form an array within 3 mm^(2)area on SiO_(2)/Si substrate.Mo_(6)Te_(6)nanowires display metallic behavior and have large charge transfer with Rhodamine 6G,making them excellent substrates for surface-enhanced Raman scattering.It shows a low detectable concentration of 10^(-13)mol/L for Rhodamine 6G and a Raman enhancement factor of 7×10^(8).Our findings provide an economic and efficient synthesis method for producing sixfold-oriented Mo_(6)Te_(6)nanowires and nanoribbons networks,which can serve as platform for exploring lowdimensional physical properties,designing electronic devices,and applications in analytical chemistry.展开更多
Mulitipe stoichiometric ratio of two-dimensional(2D)transition metal dichalcogenides(TMDCs)attracted considerable interest for their unique chemical and physical properties.Here we developed a chemical vapor depositio...Mulitipe stoichiometric ratio of two-dimensional(2D)transition metal dichalcogenides(TMDCs)attracted considerable interest for their unique chemical and physical properties.Here we developed a chemical vapor deposition(CVD)method to controllably synthesize ultrathin NiS and NiS2 nanoplates.By tuning the growth temperature and the amounts of the sulfur powder,2D nonlayered NiS and NiS2 nanoplates can be selectively prepared with the thickness of 2.0 and 7.0 nm,respectively.X-ray diffraction(XRD)and transmission electron microscopy(TEM)characterization reveal that the 2D NiS and N1S2 nanoplates are high-quality single crystals in the hexagonal and cubic phase,respectively.Electrical transport studies show that electrical conductivities of the 2D NiS and N1S2 nanoplates are as high as 4.6 x 10^5 and 6.3 x 10^5 S·m^-1,respectively.The electrical results demonstrate that the synthesized metallic NiS and NiS2 could serve as good electrodes in 2D electronics.展开更多
基金the support from National Natural Science Foundation of China(No.51872086)the Hunan Key Laboratory of Two-Dimensional Materials(Grant No.2018TP1010)the Innovative Research Groups of Hunan Province(Grant No.2020JJ1001)for the work conducted at Hunan University.
文摘Two-dimensional/one-dimensional(2D/1D)heterostructures as a new type of heterostructure have been studied for their unusual properties and promising applications in electronic and optoelectronic devices.However,the studies of 2D/1D heterostructures are mainly focused on vertical heterostructures,such as MoS_(2) nanosheet-carbon nanotubes.The research on lateral 2D/1D heterostructures with a tunable width of 1D material is still scarce.In this study,bidirectional flow chemical vapor deposition(CVD)was used to accurately control the width of the WS_(2)/WSe2(WS_(2)/MoS_(2))heterostructures by controlling reacting time.WSe2 and MoS_(2) with different widths were epitaxially grown at the edge of WS_(2),respectively.Optical microscope,atomic force microscope(AFM),and scanning electron microscope(SEM)images show the morphology and width of the heterostructures.These results show that the width of the heterostructures can be as low as 10 nm by using this method.The interface of the heterostructure is clear and smooth,which is suitable for application.This report offers a new method for the growth of 1D nanowires,and lays the foundation for the future study of the physical and chemical properties of 2D/1D lateral heterostructures.
基金the support from the National Natural Science Foundation of China(Nos.51991340,62404079,and 62404078)the open research fund of Songshan Lake Materials Laboratory(No.2023SLABFN07)+3 种基金the Natural Science Foundation of Hunan Province(No.2024JJ6135)the Natural Science Foundation of Changsha City(No.kq2402064)the Hunan Key R&D Program Project(No.2022GK2005)the National Key R&D Program of the Ministry of Science and Technology of China(No.2022YFA1203801).
文摘Two-dimensional(2D)materials,especially 2D transition metal oxides(TMOs),have garnered significant research attention due to their unique physical and chemical properties and vast potential applications in electronics,optoelectronics,magneto electronics,and energy storage.However,synthesizing 2D TMOs remains a major challenge due to their non-layered lattice structure and the high temperatures required for synthesis.In this study,we report the chemical vapor deposition-based synthesis of high-quality 2D Cr_(2)O_(3) single-crystal nanosheets and investigate their structure and electrical properties.By controlling the growth temperature and carrier gas,we successfully obtained Cr_(2)O_(3) nanosheets with lateral dimensions up to 30μm and a minimum thickness of 4.7 nm.Optical studies,X-ray diffraction,atomic force microscopy,and transmission electron microscopy confirm that the resulting nanosheets are high-quality single crystals.Electrical measurements reveal that charge transport in Cr_(2)O_(3) devices is influenced by both Schottky emission and Poole-Frenkel emission,leading to a non-equilibrium charge conduction state.This systematic synthesis approach provides a reliable route for fabricating 2D TMO single crystals with controlled thickness and offers a platform for investigating charge transfer at electrode-dielectric interfaces,as well as for the design of novel electronic materials and catalysts.
基金the financial support from the Hunan Provincial Science and Technology Plan Project(No.2020JJ4710)the Hunan Key Laboratory of Two-Dimensional Materials(No.2018TP1010)+1 种基金the postdoctoral research funding plan in Central South University(No.140050022)the support from National Natural Science Foundation of China(No.12004439)。
文摘Earth-abundant electrocatalysts for large-current-density water splitting under alkaline condition are desirable.Oxygen evolution reaction,which is a bottleneck of the overall water splitting,faces the problems of complicated reconstruction and deficiency in rational design of active sites.Herein,we report a series of transition metal chalcogenides for alkaline OER.Among them,FeCoNi(S)displayed a low overpotential of 293 m V to deliver a current density of 500 m A cm^(-2),which is in the top level of non-precious metal based OER electrocatalysts.A combination of(ex)in situ characterizations and DFT calculation shows that Ni(Fe,Co)trimetallic oxyhydroxides were the active sites for highly-efficient OER.Furthermore,for FeCoNi(S),when used as a bifunctional catalyst for water splitting,it only required a cell voltage of 1.84 V to deliver~500 m A cm^(-2) with extraordinary long-term stability over 2000 h.This work provides the comprehension of high-efficiency,robust catalysts for OER and overall water splitting at large current densities in alkaline media.
基金Project support by the National Natural Science Foundation of China(Grant Nos.61605131 and 61435010)the Shenzhen Science and Technology Research Fund,China(Grant No.JCYJ20150324141711624)
文摘Black phosphorus （BP）, an attractive two-dimensional （2D） semiconductor, is widely used in the fields of optoelec- tronic devices, biomedicine, and chemical sensing. Silver ion （Ag＋）, a commonly used additive in food industry, can sterilize and keep food fresh. But excessive intake of Ag＋ will harm human health. Therefore, high sensitive, fast and simple Ag＋ detection method is significant. Here, a high-performance BP field effect transistor （FET） sensor is fabricated for Ag＋ detection with high sensitivity, rapid detection speed, and wide detection concentration range. The detection limit for Ag＋ is 10 l0 mol/L. Testing time for each sample by this method is 60 s. Besides, the mechanism of BP-FET sensor for Ag＋ detection is investigated systematically. The simple BP-FET sensor may inspire some relevant research and potential applications, such as providing an effective method for the actual detection of Ag＋, especially in wimessed inspections field of food.
基金financially supported by Hunan Provincial Science and Technology Plan Project(Nos.2017TP1001 and 2017JJ2347)Changsha Science and Technology Plan(No.kq1801079)+1 种基金Hunan Key Laboratory of Two-Dimensional Materials(No.2018TP1010)the National Natural Science Foundation of China(No.21776317)。
文摘Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)converts CO_(2)into valuable chemical fuels,which can effectively alleviate global warming and energy crisis.However,limited by its slow reaction rate and low product selectivity,it is urgent to design efficient,cheap,safe,and highly selective CO_(2)RR electrocatalysts.Owing to the advantages of adjustable electronic structure,abundant active sites,low cost,environmental friendliness and excellent electrochemical performance,bimetallic chalcogenides have aroused great interest.Here,we briefly summarized different bimetallic oxides and sulfides for electrocatalytic CO_(2)RR in the past five years.In addition,different hybridizations formed between metal atoms,including intermetallic compounds,heterostructures and metal doping,were generalized.Their positive effects on CO_(2)RR catalytic selectivity and activity were deeply uncovered.Besides,we also put forward some views about the future research directions and perspectives in CO_(2)RR field.This review aims to provide a reference for the rational design of bimetallic chalcogenides towards electrocatalytic CO_(2)reduction.
基金financially supported by the Fundamental Research Funds of the Central Universities(no.531107051048)the support from the Hunan Key Laboratory of Two-Dimensional Materials(No.801200005)。
文摘Lithium metal is one of the most promising anode materials for next-generation electrochemical energy storage due to low electrochemical potential and high specific capacity.However,large volume change and uncontrollable formation of lithium dendrite during cycling severely hinder the practical application of rechargeable Li metal batteries.Herein,we report a hierarchically porous Cu covered with lithiophilic CuxO(HPCu-CuxO) via femtosecond laser strategy in about 2 min as current collector for highperformance Li metal batteries.With precisely tunable pore volume and depth as well as lithiophilic CuxO interphase,the HPCu-CuxO not only guides homogeneous Li nucleation,resulting in a smooth and dendrite-free lithium surface,but also provides space to alleviate the volume expansion of Li metal anode,achieving excellent structure stability.Consequently,highly stable Coulombic efficiency and ultralow overpotential of 15 mV even up to 1000 h were achieved at the current density of 1 mA cm^(-2).Moreover,the resultant Li@HPCu-CuxO//LiFePO_(4) full battery delivered outstanding cycle stability and rate capability.These results offer a pathway toward high-energy-density and safe rechargeable Li metal batteries.
基金We acknowledge the support from National Natural Science Foundation of China(Nos.61804050,51991340,51991343,and 51872086)the Fundamental Research Funds of the Central Universities(Nos.531107051078 and 531107051055)+2 种基金the Double First-Class Initiative of Hunan University(No.531109100004)the Hunan Key Laboratory of Two-Dimensional Materials(No.2018TP1010)the Strategic Priority Research Program of Chinese Academy of Science,Grant(No.XDB30000000).
文摘Palladium diselenide(PdSe2),a stable layered material with pentagonal structure,has attracted extensive interest due to its excellent electrical and optoelectronic performance.Here,we report a reliable process to synthesize PdSe2 via chemical vapor deposition(CVD)method.Through systematic regulation of temperature in the growth process,we can tune the thickness,size,nucleation density and morphology of PdSe2 nanosheets.Field-effect transistors based on PdSe2 nanosheets exhibit n-type behavior and present a high electron mobility of 105 cm^2·V^−1·s^−1.The electrical property of the devices after 6 months keeping in the air show little change,implying outstanding air-stability of PdSe2.In addition,PdSe2 near-infrared photodetector shows a photoresponsivity of 660 A·W^−1 under 914 nm laser.These performances are better than those of most CVD-grown 2D materials,making ultrathin PdSe2 a highly qualified candidate material for next-generation optoelectronic applications.
基金financially supported by the National Natural Science Foundation of China (Nos. 52074113 and 22005091)the CITIC Metals Ningbo Energy Co. Ltd. (No. H202191380246)+4 种基金Hunan Key Laboratory of Two-Dimensional Materials (No. 2018TP1010)the Fundamental Research Funds of the Central Universities (No. 531107051048)the National Natural Science Foundation of China (No. U1910208)the Graduate Research and Innovation Projects of Hunan Province (No. CX20190265)the National Natural Science Foundation of Shanxi Province (No. 201901D111137)。
文摘Lithium-ion batteries (LIBs) have exhibited extraordinary prospects due to their high energy and power density.However, the future development of LIBs is largely impeded by poor rate performance and cycling stability of the graphite anode. Here, we demonstrate a practical niobium pentoxide and graphite (Nb_(2)O_(5)/G) hybrid anode for high-performance LIBs via the scalable high-energy ball milling method.
基金This research was supported by the National Natural Science Foundation of China(Grant Nos.61605106,61875138,61435010,and 6181101252)the International Science&Technology Cooperation and Exchanges Project of Shaanxi(No.2020KW-005)+3 种基金Funded projects for the Academic Leader and Academic Backbones,Shaanxi Normal University(No.18QNGG006)Starting Grants of Shaanxi Normal University(Grant Nos.1112010209 and 1110010717)Fundamental Research Funds For the Central Universities(No.GK201802006)the Open Research Fund of State Key Laboratory of Transient Optics and Photonics,Chinese Academy of Sciences(No.SKLST201809).
文摘Narrow-bandgap materials possess the intriguing optical-electric properties and unique structures,which can be widely applied in the field of photonics,energy optoelectronic sensing and biomedicine,etc.Nowadays,the researches on nonlinear optical properties of narrow-bandgap materials have attracted extensive attention worldwide.In this paper,we review the progress of narrow-bandgap materials from many aspects,such as background,nonlinear optical properties,energy band structure,methods of preparation,and applications.These materials have obvious nonlinear optical characteristics and the interaction with the short pulse laser excitation shows the extremely strong nonlinear absorption characteristics,which leads to the optical limiting or saturable absorption related to Pauli blocking and excited state absorption.Especially,some of these novel narrow-bandgap materials have been utilized for the generation of ultrashort pulse that covers the range from the visible to mid-infrared wavelength regions.Hence,the study on these materials paves a new way for the advancement of optoelctronics devices.
基金financially supported by the National Natural Science Foundation of China(Nos.52074113,22005091 and 22005092)Hunan University Outstanding Youth Science Foundation(No.531118040319)+5 种基金the Science and Technology Innovation Program of Hunan Province(No.2021RC3055)the CITIC Metals Ningbo Energy Co.Ltd.(No.H202191380246)Chongqing Talents:Exceptional Young Talents Project(No.CQYC202105015)Shenzhen Virtual University Park Basic Research Project of Free exploration(No.2021Szvup036)the Graduate Research and Innovation Projects of Hunan Province(No.QL20210088)the Pennsylvania State University Start-Up Fund。
文摘Lithium metal is considered a desirable anode for the nextgeneration high-energy-density rechargeable energy storage devices.Unfortunately,poor lifespan and safety issues caused by unexpected dendrites growth have prevented the commercialization of Li metal anode.
基金financially supported by the National Natural Science Foundation of China(52074113,22005091,and 22005092)the Hunan University Outstanding Youth Science Foundation(531118040319)+5 种基金the Science and Technology Innovation Program of Hunan Province(2021RC3055)the Changsha Municipal Natural Science Foundation(kq2014037)the CITIC Metals Ningbo Energy Co.Ltd.(H202191380246)the Chongqing Talents:Exceptional Young Talents Project(CQYC202105015)the Shenzhen Virtual University Park Basic Research Project of Free exploration(2021Szvup036)financially supported by the Graduate Research and Innovation Projects of Hunan Province(QL20210088)。
文摘Lithium metal has gained extensive attention as the most ideal candidate for next-generation battery anode owing to the ultrahigh specific capacity and the lowest electrochemical potential.However,uncontrollable dendrite growth and huge volume variation extremely restrict the future deployment of lithium metal batteries.Herein,we report metal chalcogenide SnSSe with unique nanoplate stacking structure as a robust substrate for stable Li metal anode.During the initial Li plating process,lithiophilic Li_(22)Sn_(5) alloy and Li_(2)S/Li_(2)Se sites are obtained via in-situ electrochemical reaction of Li metal and SnSSe.Density functional theory(DFT)calculation demonstrates that the formed Li_(2)S/Li_(2)Se achieves low Li diffusion energy barrier,ensuring rapid Li~+migration.Li_(22)Sn_(5) alloy provides strong nucleation sites,promoting uniform Li nucleation.Furthermore,in-situ optical microscopy analysis suggests that the synthesized effect fundamentally inhibits lithium dendrite growth.Consequently,SnSSe modified Cu foil delivered an ultralow nucleation overpotential,superior cycling stability with 450 cycles(Coulombic efficiency,>98%),and excellent plating/stripping behavior over 2200 h at 0.5 mA cm^(-2).Moreover,the brilliant reversible cycles and rate capability were also realized in Li@SnSSe//LiFePO_(4)(LFP)full cell,shedding light on the feasibility of SnSSe for stable and dendrite-free lithium metal anode.
基金We acknowledge the support from the National Key R&D Program of the Ministry of Science and Technology of China(No.2022YFA1203801)the National Natural Science Foundation of China(grant numbers 51991340,51991343,52221001,62205055)+1 种基金the Hunan Key R&D Program Project(No.2022GK2005)Natural Science Foundation of Jiangsu Province(BK20220860).
文摘Two-dimensional(2D)transition metal dichalcogenides(TMDs)have garnered widespread interest in the scientific community and industry for their exceptional physical and chemistry properties,and great potential for applications in diverse fields including(opto)electronics,electrocatalysis,and energy storage.Chemical vapor deposition(CVD)is one of the most compelling growth methods for the scalable growth of high-quality 2D TMDs.However,the conventional CVD process for synthesis of 2D TMDs still encounters significant challenges,primarily attributed to the high melting point of precursor powders,and achieving a uniform distribution of precursor atmosphere on the substrate to obtain controllable smaple domains is difficult.The spin-coating precursor mediated chemical vapor deposition(SCVD)strategy provides refinement over traditional methods by eliminating the use of solid precursors and ensuring a more clean and uniform distribution of the growth material on the substrate.Additionally,the SCVD process allows fine-tuning of material thickness and purity by manipulating solution composition,concentration,and the spin coating process.This Review presents a comprehensive summary of recent advances in controllable growth of 2D TMDs with a SCVD strategy.First,a series of various liquid precursors,additives,source supply methods,and substrate engineering strategies for preparing atomically thin TMDs by SCVD are introduced.Then,2D TMDs heterostructures and novel doped TMDs fabricated through the SCVD method are discussed.Finally,the current challenges and perspectives to synthesize 2D TMDs using SCVD are discussed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52022029,91850116,51772084,62090035,and U19A2090)Hunan Provincial Natural Science Foundation of China(Grant Nos.2018RS3051 and 2018WK4004)the Key Program of the Hunan Provincial Science and Technology Department(Grant No.2019XK2001).
文摘Two-dimensional(2D)magnetic materials have aroused tremendous interest due to the 2D confinement of magnetism and potential applications in spintronic and valleytronic devices.However,most of the currently 2D magnetic materials are achieved by the exfoliation from their bulks,of which the thickness and domain size are difficult to control,limiting the practical device applications.Here,we demonstrate the realization of thickness-tunable rhombohedral Cr_(2)Se_(3)nanosheets on different substrates via the chemical vapor deposition route.The magnetic transition temperature at about 75 K is observed.Furthermore,van der Waals heterostructures consisting of Cr_(2)Se_(3)nanosheets and monolayer WS2 are constructed.We observe the magnetic proximity effect in the heterostructures,which manifests the manipulation of the valley polarization in monolayer WS2.Our work contributes to the vapor growth and applications of 2D magnetic materials.
基金the National Natural Science Foundation of China(nos.61505051,51902098,62090035,U19A2090,and 1217409)the Key Program of Science and Technology Department of Hunan Province(nos.2019XK2001 and 2020XK2001)+1 种基金the Science and Technology Innovation Program of Hunan Province(no.2021RC3061)the Natural Science Foundation of Hunan Province(nos.2021JJ20016 and 2021JJ30132).
文摘CONSPECTUS:Two-dimensional(2D)heterostructures have created many novel properties and triggered a variety of promising applications,thus setting off a boom in the modern semiconductor industry.As the first road to step into adequately exploring the properties and real applications,the material preparation process matters a lot.Adhering to the concept of epitaxial growth,chemical vapor deposition(CVD)shows great potential for the preparation of heterostructures for commercialization.
基金National Key R&D Program of the Ministry of Science and Technology of China,Grant/Award Number:2022YFA1203801The National Natural Science Foundation of China,Grant/Award Numbers:51991340,51991343,52221001,62174051+1 种基金The Hunan Key R&D Program Project,Grant/Award Number:2022GK2005Ningbo Natural Science Foundation,Grant/Award Number:2023J023。
文摘The controllable synthesis of complicated nanostructures in advanced two-dimensional(2D)semiconductors,such as periodic regular hole arrays,is essential and remains immature.Here,we report a green,facile,highly controlled synthetic method to efficiently pattern 2D semiconductors,such as periodic regular hexagonal-shaped hole arrays(HHA),in 2D-TMDs.Combining the production of artificial defect arrays through laser irradiation with anisotropic annealing etching,we created HHA with different arrangements,controlled hole sizes,and densities in bilayer WS_(2).Atomic force microscopy(AFM),Raman,photoluminescence(PL),and scanning transmission electron microscopy(STEM)characterization show that the 2D semiconductors have high quality with atomical clean and sharp edges as well as undamaged crystals in the unetched region.Furthermore,other nanostructures,such as nanoribbons and periodic regular triangular-shaped 2D-TMD arrays,can be fabricated.This kind of 2D semiconductors fabrication strategy is general and can be extended to a series of 2D materials.Density functional theory(DFT)calculations show that one WS_(2)molecule from the edges of the laser-irradiated holed region exhibits a robust etching activation,making selective etching at the artificial defects and the fabrication of regular 2D semiconductors possible.
基金financially supported by the National Key Research and Development Program of China (Grant No. 2017YFA0207500)the National Natural Science Foundation of China (Grant No. 62125404)the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB43000000)
文摘A magnetic semiconductor whose electronic charge and spin can be regulated together will be an important compon-ent of future spintronic devices.Here,we construct a two-dimensional(2D)Fe doped SnS_(2)(Fe-SnS_(2))homogeneous junction and investigate its electromagnetic transport feature.The Fe-SnS_(2) homojunction device showed large positive and unsatur-ated magnetoresistance(MR)of 1800%in the parallel magnetic field and 600%in the vertical magnetic field,indicating an obvi-ous anisotropic MR feature.In contrast,The MR of Fe-SnS_(2) homojunction is much larger than the pure diamagnetic SnS_(2) and most 2D materials.The application of a gate voltage can regulate the MR effect of Fe-SnS_(2) homojunction devices.Moreover,the stability of Fe-SnS_(2) in air has great application potential.Our Fe-SnS_(2) homojunction has a significant potential in future mag-netic memory applications.
基金This work was granted by the National Key Research and Development Program of the of China(No.2022YFA1203801)the National Natural Science Foundation of China(Nos.51991340,51991343,52221001,52102168,and 52372145)+4 种基金Hunan Key Research and Development Program Project(No.2022GK2005)the Natural Science Foundation of Hunan Province(No.2023JJ20009)the Hunan Province“Huxiang Talents”Project(No.2023RC3092)the Natural Science Foundation of Chongqing,China(No.cstc2021jcyj-msxmX0321)the Doctoral Scientific Research Foundation of Hubei University of Automotive Technology(No.BK202486).
文摘Large-scale synthesis of high-quality two dimensional(2D)semiconductors,such as molybdenum disulfide(MoS_(2)),is a prerequisite for their lab-to-fab transition.It is crucial to systematically explore and understand the influence of key synthetic conditions on the nucleation,uniformity,and quality of MoS_(2) wafers.Here,we report the epitaxial growth of high-quality and uniform monolayer MoS_(2) films on 2-in c-plane sapphire by chemical vapor deposition(CVD)method under optimized growth conditions(0–1 mg NaCl,adequate S/Mo ratio,and the addition of 0–1 sccm O2).We systematically explore the influence of critical synthetic conditions on the nucleation,and stitching of MoS_(2) domains over the wafer scale,including the dosage of the alkali metal salt NaCl additive,the evaporation temperature of MoO_(3),the distance between MoO_(3) and the substrate,and the flow rate of O_(2).Among them,the dosage of NaCl and the S/Mo ratio have important influences on the quality and film coverage of MoS_(2),while the flow rate of O_(2) plays a key role in controlling the nucleation density and domain size.We further discovered that a-plane sapphire could easily guide the unidirectional growth of MoS_(2) without the need for other specific synthetic conditions compared with c-plane and m-plane sapphire.The field-effect transistors(FETs)fabricated from the full-coverage films show an average and the highest mobilities of 28.5 and around 45 cm^(2)·V−1·s^(-1),respectively.
基金supported by the National Natural Science Foundation of China(Nos:22568047 and 22278348)the Natural Science Foundation of Xinjiang Autonomous Region(No.2022D01D05)+2 种基金the Shanghai Cooperation Organization Science and Technology Partnership Program and International Science and Technology Cooperation Program(No.2022E01059)the Scientific Research Program of Higher Education Institution of Xinjiang(No.XJEDU2024P014)Xinjiang University Excellent Doctoral Student Innovation Project(No.XJU2024BS061).
文摘The design and application of single-atom catalysts have gained significant attention in photocatalysis.However,precisely and firmly anchoring single atoms on substrate surfaces remains a challenge.This study employs an innovative silane coupling agent grafting strategy to precisely and stably anchor Cu single-atoms on the substrate.Scanning ransmission lectron microscopy(STEM)and X-ray absorption fine structure spectroscopy(XAFS)confirm the successful loading of Cu single-atoms.Photoelectric tests show that the stable channel formed by the carbon chain effectively enhances carrier separation and transport efficiency between Cu and the substrate.Density functional theory(DFT)calculations indicate that the adsorption energy barrier of the intermediate product is reduced by 0.106 eV,improving the reaction kinetics.After grafting with the silane coupling agent,the performance of Cu single-atom-loaded materials is further enhanced by 12.16 times.The strong anchoring prevents Cu single-atom detachment and aggregation during photocatalysis,while excess charge carriers produced by Cu atoms are efficiently transferred to the substrate for reaction.Compared to traditional Cu single-atom supported catalysts,the grafted samples in this study demonstrate superior performance and stability in photocatalytic reduction reactions.This approach provides a reliable and innovative pathway for the directional and stable production of single-atom catalysts.
基金support from Research Groups of the National Natural Science Foundation of China(No.52121004)Hunan Key R&D Program Project(No.2022GK2005)+1 种基金the National Key R&D Program of the Ministry of Science and Technology of China(No.2022YFA1203801)the National Natural Science Foundation of China(Nos.51991340 and 51991343).
文摘Phase transition and edge structure reconstruction of twodimensional(2D)materials are critical for modulating their properties and applications.Here,we employ a hydrogen-assisted annealing method to accomplish the extensive transformation from a 2H MoTe_(2)single crystal to Mo_(6)Te_(6)nanowires and quasi-2D Mo_(6)Te_(6)nanoribbons.Introducing hydrogen gas during atmospheric pressure annealing process generates a Te-poor chemical environment,which makes the transformations energetically favorable and is essential for the fast growth of Mo_(6)Te_(6)nanowires.Mo_(6)Te_(6)nanowires nucleate at the exposed edges of 2H MoTe_(2)and grow along its[1120],[2110],and[1210]crystallographic directions,demonstrating long-range order and forming quais-2D nanoribbons with lengths up to 50μm.Finally,nanoribbons align in sixfold oriented directions and form an array within 3 mm^(2)area on SiO_(2)/Si substrate.Mo_(6)Te_(6)nanowires display metallic behavior and have large charge transfer with Rhodamine 6G,making them excellent substrates for surface-enhanced Raman scattering.It shows a low detectable concentration of 10^(-13)mol/L for Rhodamine 6G and a Raman enhancement factor of 7×10^(8).Our findings provide an economic and efficient synthesis method for producing sixfold-oriented Mo_(6)Te_(6)nanowires and nanoribbons networks,which can serve as platform for exploring lowdimensional physical properties,designing electronic devices,and applications in analytical chemistry.
基金We acknowledge the support from the National Natural Science Foundation of China(No.51872086)the Hunan Key Laboratory of Two-Dimensional Materials(No.2018TP1010)+1 种基金the Strategic Priority Research Program of Chinese Academy of Science(No.XDB30000000)the National Key Research and Development Program of Ministry of Science and Technology(No.2018YFA0703704).
文摘Mulitipe stoichiometric ratio of two-dimensional(2D)transition metal dichalcogenides(TMDCs)attracted considerable interest for their unique chemical and physical properties.Here we developed a chemical vapor deposition(CVD)method to controllably synthesize ultrathin NiS and NiS2 nanoplates.By tuning the growth temperature and the amounts of the sulfur powder,2D nonlayered NiS and NiS2 nanoplates can be selectively prepared with the thickness of 2.0 and 7.0 nm,respectively.X-ray diffraction(XRD)and transmission electron microscopy(TEM)characterization reveal that the 2D NiS and N1S2 nanoplates are high-quality single crystals in the hexagonal and cubic phase,respectively.Electrical transport studies show that electrical conductivities of the 2D NiS and N1S2 nanoplates are as high as 4.6 x 10^5 and 6.3 x 10^5 S·m^-1,respectively.The electrical results demonstrate that the synthesized metallic NiS and NiS2 could serve as good electrodes in 2D electronics.
