The optimized growth parameters of graphene with different morphologies,such as dendrites,rectangle,and hexagon,have been obtained by low-pressure chemical vapor deposition on polycrystalline copper substrates.The evo...The optimized growth parameters of graphene with different morphologies,such as dendrites,rectangle,and hexagon,have been obtained by low-pressure chemical vapor deposition on polycrystalline copper substrates.The evolution of fractal graphene,which grew on the polycrystalline copper substrate,has also been observed.When the equilibrium growth state of graphene is disrupted,its intrinsic hexagonal symmetry structure will change into a non-hexagonal symmetry structure.Then,we present a systematic and comprehensive study of the evolution of graphene with different morphologies grown on solid copper as a function of the volume ratio of methane to hydrogen in a controllable manner.Moreover,the phenomena of stitching snow-like graphene together and stacking graphene with different angles was also observed.展开更多
Using first-principle calculations, we predict a new family of stable two-dimensional(2 D) topological insulators(TI),monolayer Be_3 X_2(X = C,Si, Ge, Sn) with honeycomb Kagome lattice. Based on the configuration of B...Using first-principle calculations, we predict a new family of stable two-dimensional(2 D) topological insulators(TI),monolayer Be_3 X_2(X = C,Si, Ge, Sn) with honeycomb Kagome lattice. Based on the configuration of Be_3 C_2, which has been reported to be a 2 D Dirac material, we construct the other three 2 D materials and confirm their stability according to their chemical bonding properties and phonon-dispersion relationships. Because of their tiny spin-orbit coupling(SOC)gaps, Be_3 C_2 and Be_3 Si_2 are 2 D Dirac materials with high Fermi velocity at the same order of magnitude as that of graphene.For Be3 Ge2 and Be_3 Sn_2,the SOC gaps are 1.5 meV and 11.7 meV, and their topological nontrivial properties are also confirmed by their semi-infinite Dirac edge states. Our findings not only extend the family of 2 D Dirac materials, but also open an avenue to track new 2 DTI.展开更多
Strain engineering is a vital way to manipulate the electronic properties of two-dimensional(2D)materials.As a typical representative of transition metal mono-chalcogenides(TMMs),a honeycomb CuSe monolayer features wi...Strain engineering is a vital way to manipulate the electronic properties of two-dimensional(2D)materials.As a typical representative of transition metal mono-chalcogenides(TMMs),a honeycomb CuSe monolayer features with one-dimensional(1D)moirépatterns owing to the uniaxial strain along one of three equivalent orientations of Cu(111)substrates.Here,by combining low-temperature scanning tunneling microscopy/spectroscopy(STM/S)experiments and density functional theory(DFT)calculations,we systematically investigate the electronic properties of the strained CuSe monolayer on the Cu(111)substrate.Our results show the semiconducting feature of CuSe monolayer with a band gap of 1.28 eV and the 1D periodical modulation of electronic properties by the 1D moirépatterns.Except for the uniaxially strained CuSe monolayer,we observed domain boundary and line defects in the CuSe monolayer,where the biaxial-strain and strain-free conditions can be investigated respectively.STS measurements for the three different strain regions show that the first peak in conduction band will move downward with the increasing strain.DFT calculations based on the three CuSe atomic models with different strain inside reproduced the peak movement.The present findings not only enrich the fundamental comprehension toward the influence of strain on electronic properties at 2D limit,but also offer the benchmark for the development of 2D semiconductor materials.展开更多
The magnetism of nanographene is dominated by the structure of its carbon skeleton.However,the magnetism engineering of nanographene is hindered due to finite precursors.Here,we demonstrate an ingenious synthetic stra...The magnetism of nanographene is dominated by the structure of its carbon skeleton.However,the magnetism engineering of nanographene is hindered due to finite precursors.Here,we demonstrate an ingenious synthetic strategy to engineer the magnetism of nanographene through hetero-coupling two precursors on Au(111)surface.Bond-resolved scanning tunneling microscopy and spectroscopy results show that two homo-coupled products host a closed-shell structure,while the products with five membered ring defects perform as an open-shell one with the total spin number of 1/2,confirmed by spin-polarized density functional theory calculations.While two hetero precursors on Au(111)substrate,the heterocoupled products both perform as the magnetic structure with total spin quantum numbers of 1/2 and 1,resulting from carbon skeleton transformations.Our work provides an effective way to engineer the magnetism of nanographene by enriching the magnetic products simultaneous,which could be extended into other controllable magnetic nanographene instruction.展开更多
Graphene nanoribbons(GNRs)not only share many superlative properties of graphene but also display an exceptional degree of tunability of their electronic properties.The bandgaps of GNRs depend greatly on their widths,...Graphene nanoribbons(GNRs)not only share many superlative properties of graphene but also display an exceptional degree of tunability of their electronic properties.The bandgaps of GNRs depend greatly on their widths,edges,etc.Herein,we report the synthesis path and the physical properties of atomic accuracy staggered narrow N=8 armchair graphene nanoribbons(sn-8AGNR)with alternating"Bite"defects on the opposite side.The intermediate structures in the surface physicochemical reactions from the precursors to the sn-8AGNR are characterized by scanning tunneling microscopy.The electronic properties of the sn-8AGNR are characterized by scanning tunneling spectroscopies and 6//6V mappings.Compared with the perfect N=8 armchair graphene nanoribbons(8AGNR),the sn-8AGNR has a larger bandgap,indicating that the liB\Xen edges can effectively regulate the electronic structures of GNRs.展开更多
Nanoscale low-dimensional chiral architectures are increasingly receiving scientific interest,because of their potential applications in many fields such as chiral recognition,separation and transformation.Using 6,12-...Nanoscale low-dimensional chiral architectures are increasingly receiving scientific interest,because of their potential applications in many fields such as chiral recognition,separation and transformation.Using 6,12-dibromochrysene(DBCh),we successfully constructed and characterized the large-area two-dimensional chiral networks on Au(111)and one-dimensional metal-liganded chiral chains on Cu(111)respectively.The reasons and processes of chiral transformation of chiral networks on Au(111)were analyzed.We used scanning tunneling spectroscopy(STS)to analyze the electronic state information of this chiral structure.This work combines scanning tunneling microscopy(STM)with non-contact atomic force microscopy(nc-AFM)techniques to achieve ultra-high-resolution characterization of chiral structures on low-dimensional surfaces,which may be applied to the bond analysis of functional nanofilms.Density functional theory(DFT)was used to simulate the adsorption behavior of the molecular and energy analysis in order to verify the experimental results.展开更多
Bladder cancer is a common malignant tumor of the urinary system with the potential to be treated by nano drug delivery system.The current work describes the synthesis and characterization of a novel nanomaterial to c...Bladder cancer is a common malignant tumor of the urinary system with the potential to be treated by nano drug delivery system.The current work describes the synthesis and characterization of a novel nanomaterial to construct a nano-carrier based on 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphatecholine(POPC)loaded doxorubicin(DOX)and embedded with gold nanoparticles and poly(N-isopropyl acry-lamide)(PNIPAM)(GNPS@PNIPAM-POPC-DOX,GPPD).The dual-sensitive nanosystem gives simultaneous photothermal treatment and chemotherapy for bladder cancer.In vitro and in vivo properties were as-sessed using bladder cancer cell lines and mice and GPPD system distribution,tumor inhibition,and biocompatibility are reported.The system had favorable stability,low biological toxicity,controlled re-lease efficiency,photothermal synergistic action,efficient photothermal transition,and favorable tumor suppressive effects.As a result,GPPD is a potential therapeutic approach for bladder cancer.展开更多
基金This work was financially supported by the National Nat-ural Science Foundation of China(Nos.11674136,11564022,and 51402138)the Thousand Talents Plan-The Recruitment Program for Young Professionals(No.1097816002)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB30010000)the Yunnan Province for Recruiting High-Caliber Technological Talents(No.1097816002)the Reserve Talents for Yun-nan Young and Middle-aged Academic and Technical Lead-ers(No.2017HB010).
文摘The optimized growth parameters of graphene with different morphologies,such as dendrites,rectangle,and hexagon,have been obtained by low-pressure chemical vapor deposition on polycrystalline copper substrates.The evolution of fractal graphene,which grew on the polycrystalline copper substrate,has also been observed.When the equilibrium growth state of graphene is disrupted,its intrinsic hexagonal symmetry structure will change into a non-hexagonal symmetry structure.Then,we present a systematic and comprehensive study of the evolution of graphene with different morphologies grown on solid copper as a function of the volume ratio of methane to hydrogen in a controllable manner.Moreover,the phenomena of stitching snow-like graphene together and stacking graphene with different angles was also observed.
基金supported by the National Natural Science Foundation of China(Grant Nos.11674136 and 11564022)the Thousand Talents Plan-the Recruitment Program for Young Professionals,China(Grant No.1097816002)+4 种基金Yunnan Province for Recruiting High-Caliber Technological Talents,China(Grant No.1097816002)Reserve Talents for Yunnan Young and Middle-aged Academic and Technical Leaders,China(Grant No.2017HB010)the Academic Qinglan Project of Kunming University of Science and Technology(KUST),China(Grant No.1407840010)the Analysis and Testing Fund of KUST,China(Grant No.2017M20162230010)the High-level Talents of KUST,China(Grant No.1411909425)
文摘Using first-principle calculations, we predict a new family of stable two-dimensional(2 D) topological insulators(TI),monolayer Be_3 X_2(X = C,Si, Ge, Sn) with honeycomb Kagome lattice. Based on the configuration of Be_3 C_2, which has been reported to be a 2 D Dirac material, we construct the other three 2 D materials and confirm their stability according to their chemical bonding properties and phonon-dispersion relationships. Because of their tiny spin-orbit coupling(SOC)gaps, Be_3 C_2 and Be_3 Si_2 are 2 D Dirac materials with high Fermi velocity at the same order of magnitude as that of graphene.For Be3 Ge2 and Be_3 Sn_2,the SOC gaps are 1.5 meV and 11.7 meV, and their topological nontrivial properties are also confirmed by their semi-infinite Dirac edge states. Our findings not only extend the family of 2 D Dirac materials, but also open an avenue to track new 2 DTI.
基金the National Natural Science Foundation of China(Nos.62271238 and 61901200)the Yunnan Fundamental Research Projects(Nos.202201AT070078,202101AV070008,202101AW070010,and 202101AU070043)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(XDB30000000)the Analysis and Testing Foundation of KUST(2021T20170056)the Dongguan Innovation Research Team Program.Numerical computations were performed on Hefei advanced computing center.
文摘Strain engineering is a vital way to manipulate the electronic properties of two-dimensional(2D)materials.As a typical representative of transition metal mono-chalcogenides(TMMs),a honeycomb CuSe monolayer features with one-dimensional(1D)moirépatterns owing to the uniaxial strain along one of three equivalent orientations of Cu(111)substrates.Here,by combining low-temperature scanning tunneling microscopy/spectroscopy(STM/S)experiments and density functional theory(DFT)calculations,we systematically investigate the electronic properties of the strained CuSe monolayer on the Cu(111)substrate.Our results show the semiconducting feature of CuSe monolayer with a band gap of 1.28 eV and the 1D periodical modulation of electronic properties by the 1D moirépatterns.Except for the uniaxially strained CuSe monolayer,we observed domain boundary and line defects in the CuSe monolayer,where the biaxial-strain and strain-free conditions can be investigated respectively.STS measurements for the three different strain regions show that the first peak in conduction band will move downward with the increasing strain.DFT calculations based on the three CuSe atomic models with different strain inside reproduced the peak movement.The present findings not only enrich the fundamental comprehension toward the influence of strain on electronic properties at 2D limit,but also offer the benchmark for the development of 2D semiconductor materials.
基金supported by the National Natural Science Foundation of China(No.61901200)the National Recruitment Program for Young Professionals(No.132310976002)+2 种基金the Yunnan Fundamental Research Projects(Nos.2019FD041,202101AV070008,202101AW070010 and 202101AU070043)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB30000000)the Dongguan Innovation Research Team Program。
文摘The magnetism of nanographene is dominated by the structure of its carbon skeleton.However,the magnetism engineering of nanographene is hindered due to finite precursors.Here,we demonstrate an ingenious synthetic strategy to engineer the magnetism of nanographene through hetero-coupling two precursors on Au(111)surface.Bond-resolved scanning tunneling microscopy and spectroscopy results show that two homo-coupled products host a closed-shell structure,while the products with five membered ring defects perform as an open-shell one with the total spin number of 1/2,confirmed by spin-polarized density functional theory calculations.While two hetero precursors on Au(111)substrate,the heterocoupled products both perform as the magnetic structure with total spin quantum numbers of 1/2 and 1,resulting from carbon skeleton transformations.Our work provides an effective way to engineer the magnetism of nanographene by enriching the magnetic products simultaneous,which could be extended into other controllable magnetic nanographene instruction.
基金support by the National Natural Science Foundation of China(Nos.11674136,61901200,51662023,and 51861020)The National Recruitment Program for Young Professionals(No.1097816002)+2 种基金Yunnan Province for Recruiting High-Caliber Technological Talents(No.1097816002)reserve talents for Yunnan young and middle aged academic and technical leaders(No.2017HB010)the Yunnan Province Science and Technology Plan Project(No.2019FD041).Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB30010000).
文摘Graphene nanoribbons(GNRs)not only share many superlative properties of graphene but also display an exceptional degree of tunability of their electronic properties.The bandgaps of GNRs depend greatly on their widths,edges,etc.Herein,we report the synthesis path and the physical properties of atomic accuracy staggered narrow N=8 armchair graphene nanoribbons(sn-8AGNR)with alternating"Bite"defects on the opposite side.The intermediate structures in the surface physicochemical reactions from the precursors to the sn-8AGNR are characterized by scanning tunneling microscopy.The electronic properties of the sn-8AGNR are characterized by scanning tunneling spectroscopies and 6//6V mappings.Compared with the perfect N=8 armchair graphene nanoribbons(8AGNR),the sn-8AGNR has a larger bandgap,indicating that the liB\Xen edges can effectively regulate the electronic structures of GNRs.
基金supported by the National Natural Science Foundation of China(Nos.51861020,61901200 and 12064020)the National Recruitment Program for Young Professionals(No.132310976002)+4 种基金the Yunnan Province Science and Technology Plan Project(No.2019FD041)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB30010000)the Reserve Talents for Yunnan Young and Middle Aged Academic and Technical Leaders(No.2017HB010)the Yunnan Province for Recruiting High-Caliber Technological Talents(No.1097816002)Yunnan Fundamental Research Projects(No.202101AU070043).
文摘Nanoscale low-dimensional chiral architectures are increasingly receiving scientific interest,because of their potential applications in many fields such as chiral recognition,separation and transformation.Using 6,12-dibromochrysene(DBCh),we successfully constructed and characterized the large-area two-dimensional chiral networks on Au(111)and one-dimensional metal-liganded chiral chains on Cu(111)respectively.The reasons and processes of chiral transformation of chiral networks on Au(111)were analyzed.We used scanning tunneling spectroscopy(STS)to analyze the electronic state information of this chiral structure.This work combines scanning tunneling microscopy(STM)with non-contact atomic force microscopy(nc-AFM)techniques to achieve ultra-high-resolution characterization of chiral structures on low-dimensional surfaces,which may be applied to the bond analysis of functional nanofilms.Density functional theory(DFT)was used to simulate the adsorption behavior of the molecular and energy analysis in order to verify the experimental results.
基金funded by the National Natural Science Foundation of China(Nos.92059112,82072821,31470964)the Shanghai Songjiang Municipal Science and Technology Commission Natural Science Foundation(No.20SJKJGG250)+1 种基金University of Shan-hai for Science and Technology(No.10-21-302-405)sponsored by the Program of Shanghai Academic Research Leader(No.22XD1404700).
文摘Bladder cancer is a common malignant tumor of the urinary system with the potential to be treated by nano drug delivery system.The current work describes the synthesis and characterization of a novel nanomaterial to construct a nano-carrier based on 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphatecholine(POPC)loaded doxorubicin(DOX)and embedded with gold nanoparticles and poly(N-isopropyl acry-lamide)(PNIPAM)(GNPS@PNIPAM-POPC-DOX,GPPD).The dual-sensitive nanosystem gives simultaneous photothermal treatment and chemotherapy for bladder cancer.In vitro and in vivo properties were as-sessed using bladder cancer cell lines and mice and GPPD system distribution,tumor inhibition,and biocompatibility are reported.The system had favorable stability,low biological toxicity,controlled re-lease efficiency,photothermal synergistic action,efficient photothermal transition,and favorable tumor suppressive effects.As a result,GPPD is a potential therapeutic approach for bladder cancer.