We have studied the two-and three-photon absorption(2PA and 3PA) properties of Mn-doped CsPbCl_3 twodimensional nanoplatelets(2D NPs) and cubic nanocrystals. Compared with their cubic counterparts, the Mn-doped 2D NPs...We have studied the two-and three-photon absorption(2PA and 3PA) properties of Mn-doped CsPbCl_3 twodimensional nanoplatelets(2D NPs) and cubic nanocrystals. Compared with their cubic counterparts, the Mn-doped 2D NPs exhibit stronger quantum confinement effects that can more efficiently enhance their dopantcarrier exchange interactions and multiphoton absorption. More specifically, the maximum volume-normalized 2PA and 3PA cross sections of the 2D NPs were 6.8 and 7.2 times greater than those of their cubic counterparts,respectively, reaching up to 1237 GM∕nm^3 in the visible light band and 2.24 × 10^(-78) cm^6· s^2· photon^(-2)∕nm^3 in the second biological window, respectively.展开更多
Two-dimensional electrophoresis(2-DE) of protein extracted and purified from Alexandrium sp. LC3 was conducted. In the SDS-PAGE study, the relative molecular weights of the proteins were mainly in the range of 14 kD...Two-dimensional electrophoresis(2-DE) of protein extracted and purified from Alexandrium sp. LC3 was conducted. In the SDS-PAGE study, the relative molecular weights of the proteins were mainly in the range of 14 kDa-31 kDa and 43 kDa-66 kDa, and more proteins were detected between 14kDa and 31 kDa. With the improved protein preparation, the two-dimensional electrophoresis patterns indicated that the relative molecular weights of the proteins were between 14kDa and 100kDa, and most of them ranged from 14 kDa to 31 kDa. This was consistent with the result of the SDS-PAGE analysis. The isoelectric points were found to lie between 3.0 and 8.0, and most of them were in the range of 3.0-6.0. Better separation effect was acquired with pre-prepared immobilized gradient (IPG) strip (pH 3-5.6), and about 320 protein spots could be visualized on the 2-DE map by staining. Within pH 3-l0 and pH 3-5.6 strips, the protein samples of Alexandrium sp. LC3 could be separated well.展开更多
The first-principles calculations are employed to investigate the electrical properties of polar MgO/BaTiO3(110)interfaces. Both n-type and p-type polar interfaces show a two-dimensional metallic behavior. For the n...The first-principles calculations are employed to investigate the electrical properties of polar MgO/BaTiO3(110)interfaces. Both n-type and p-type polar interfaces show a two-dimensional metallic behavior. For the n-type polar interface,the interface Ti3d electrons are the origin of the metallic and magnetic properties. Varying the thickness of Ba TiO3 may induce an insulator–metal transition, and the critical thickness is 4 unit cells. For the p-type polar interface, holes preferentially occupy the interface O 2p y state, resulting in a conducting interface. The unbalance of the spin splitting of the O 2p states in the interface Mg O layer leads to a magnetic moment of about 0.25μB per O atom at the interface.These results further demonstrate that other polar interfaces, besides LaAlO3/SrTiO3, can show a two-dimensional metallic behavior. It is helpful to fully understand the role of polar discontinuity on the properties of the interface, which widens the field of polar-nonpolar interfaces.展开更多
Organometallic nanosheets are a versatile platform for design of efficient electrocatalyst materials due to their high surface area and uniform dispersion of metal active sites.In this paper,we systematically investig...Organometallic nanosheets are a versatile platform for design of efficient electrocatalyst materials due to their high surface area and uniform dispersion of metal active sites.In this paper,we systematically investigate the electrocatalytic performance of the first transition metal series TM3–C12S12 monolayers on CO2 using spin-polarized density functional theory.The calculations show that M3–C12S12 exhibits excellent catalytic activity and selectivity in the catalytic reduction in CO2.The main reduction products of Sc,Ti,and Cr are CH4.V,Mn,Fe and Zn mainly produce HCOOH,and Co produces HCHO,while CO is the main product for Ni and Cu.For Sc,Ti,and Cr,the overpotentials are>0.7 V,while for V,Mn,Fe,Co,Ni,Cu,Zn,the overpotentials are very low and range from 0.27 to 0.47 V.Therefore,our results indicate that many of the M3–C12S12 monolayers are expected to be excellent and efficient CO2 reduction catalysts.展开更多
Fabricating high-quality cesium lead chloride(CsPbCl_3) perovskite nanowires(NWs) with dimension below 10 nm is not only of interests in fundamental physics, but also holds the great promise for optoelectronic applica...Fabricating high-quality cesium lead chloride(CsPbCl_3) perovskite nanowires(NWs) with dimension below 10 nm is not only of interests in fundamental physics, but also holds the great promise for optoelectronic applications. Herein, ultrathin CsPbCl_3 NWs with height of ~7 nm, have been achieved via vapor phase deposition method. Power and temperature-dependent photoluminescence(PL) spectroscopy is performed to explore the emission properties of the CsPbCl_3 NWs. Strong free exciton recombination is observed at ~3.02 eV as the temperature(T) is 78-294 K with binding energy of ~ 37.5 meV. With the decreasing of T, the PL peaks exhibit a first blueshift by 2 meV for T ~ 294-190 K and then a redshift by 4 meV for T ~ 190-78 K. The exciton–optical phonon interaction plays a major role in the linewidth broadening of the PL spectra with average optical phonon energy of ~48.0 meV and the interaction coefficient of 203.9 meV. These findings advance the fabrication of low dimensional CsPbCl_3 perovskite and provide insights into the photophysics of the CsPbCl_3 perovskite.展开更多
Our recent experimental work on metallic and insulating interfaces controlled by interfacial redox reactions in SrTiO3-based heterostructures is reviewed along with a more general background of two-dimensional electro...Our recent experimental work on metallic and insulating interfaces controlled by interfacial redox reactions in SrTiO3-based heterostructures is reviewed along with a more general background of two-dimensional electron gas (2DEG) at oxide interfaces. Due to the presence of oxygen vacancies at the SrTiO3 surface, metallic conduction can be created at room temperature in perovskite-type interfaces when the overlayer oxide ABO3 has Al, Ti, Zr, or Hf elements at the B sites. Furthermore, relying on interface-stabilized oxygen vacancies, we have created a new type of 2DEG at the heterointerface between SrTiO3 and a spinel γ-Al2O3 epitaxial film with compatible oxygen ion sublattices. This 2DEG exhibits an electron mobility exceeding 100000 cm2·V-1·s-1, more than one order of magnitude higher than those of hitherto investigated perovskite-type interfaces. Our findings pave the way for the design of high-mobility all-oxide electronic devices and open a route toward the studies of mesoscopic physics with complex oxides.展开更多
Recent years,membrane separation technology has attracted significant research attention because of the efficient and environmentally friendly operation.The selection of suitable materials to improve the membrane sele...Recent years,membrane separation technology has attracted significant research attention because of the efficient and environmentally friendly operation.The selection of suitable materials to improve the membrane selectivity,permeability and other properties has become a topic of vital research relevance.Two-dimensional(2D)materials,a novel family of multifunctional materials,are widely used in membrane separation due to their unique structure and properties.In this respect,as a novel 2D material,graphitic carbon nitride(g-C_(3)N_(4))have found specific attention in membrane separation.This study reviews the application of carbon nitride in gas separation membranes,pervaporation membranes,nanofiltration membranes,reverse osmosis membranes,ion exchange membranes and catalytic membranes,along with describing the separation mechanisms.展开更多
In recent years, with the level of science and technology progress, largely to promote the development of animation techniques. Animated film is divided into two-dimensional animation and three-dimensional animation, ...In recent years, with the level of science and technology progress, largely to promote the development of animation techniques. Animated film is divided into two-dimensional animation and three-dimensional animation, both in the retention feature animated films, based on the performance of each with different strengths, thus forming a different artistic style. Wherein the two-dimensional animation is the most common one is the most basic form of expression in animation technology is relatively mature and complete, but because of the development of animation techniques, two-dimensional animation can not meet the needs of the audience. Thus, the effective combination of two-dimensional animation and three-dimensional animation technology, the advantages of integration between the two is particularly important, so that innovation in the form of screen performance, enhance audio-visual experience. In this paper, two-dimensional animation and three-dimensional animation skills fusion analysis and research, and put forward a number of specific observations, in order to learn.展开更多
For the first time,we report high-performance two-dimensional(2D)perovskite Pb_(2)Nb_(3)O_(10) photodetectors(PNO PDs).The few-layer PNO nanosheets are obtained successfully through a simple calcination and liquid exf...For the first time,we report high-performance two-dimensional(2D)perovskite Pb_(2)Nb_(3)O_(10) photodetectors(PNO PDs).The few-layer PNO nanosheets are obtained successfully through a simple calcination and liquid exfoliation method.The individual PNO nanosheet devices with various structures(Au-PNO-Au,Au-PNO-Ti,Ti-PNO-Ti)are fabricated and investigated.The Au-PNO-Ti device exhibits a high rectification factor(∼102)owing to a large Schottky barrier difference between the PNO nanosheet and two asymmetric electrodes.Notably,the Au-PNO-Ti device shows excellent self-powered performance,including high responsivity(2.8 A/W),high detectivity(1.1×10^(12) Jones),and fast speed(0.2/1.2 ms)at 350 nm light illumination.This work not only suggests the performance of the PNO nanosheet PDs but also sheds light on the development of high-stability and high-performance devices based on 2D perovskite niobate in the future.展开更多
An improved algorithm for computing multiphase flows is presented in which the multimaterial Moment-of-Fluid(MOF)algorithm for multiphase flows,initially described by Li et al.(2015),is enhanced addressing existing MO...An improved algorithm for computing multiphase flows is presented in which the multimaterial Moment-of-Fluid(MOF)algorithm for multiphase flows,initially described by Li et al.(2015),is enhanced addressing existing MOF difficulties in computing solutions to problems in which surface tension forces are crucial for understanding salient flow mechanisms.The Continuous MOF(CMOF)method is motivated in this article.The CMOF reconstruction method inherently removes the"checkerboard instability"that persists when using the MOF method on surface tension driven multiphase(multimaterial)flows.The CMOF reconstruction algorithm is accelerated by coupling the CMOF method to the level set method and coupling the CMOF method to a decision tree machine learning(ML)algorithm.Multiphase flow examples are shown in the two-dimensional(2D),three-dimensional(3D)axisymmetric"RZ",and 3D coordinate systems.Examples include two material and three material multiphase flows:bubble formation,the impingement of a liquid jet on a gas bubble in a cryogenic fuel tank,freezing,and liquid lens dynamics.展开更多
Two compounds with 3-methylbenzoic acid(HL) [Co(L)2(4,4'-bipy)]n 1 and [Zn2(L)4(4,4'-bipy)]n 2(L = 3-methylbenzoic acid) have been hydrothermally synthesized directly and characterized by single-crystal ...Two compounds with 3-methylbenzoic acid(HL) [Co(L)2(4,4'-bipy)]n 1 and [Zn2(L)4(4,4'-bipy)]n 2(L = 3-methylbenzoic acid) have been hydrothermally synthesized directly and characterized by single-crystal X-ray diffraction analysis,elemental analyses,IR spectra and ultraviolet-visible diffuse reflection integral spectra(UV-Vis DRIS).The two compounds are both one-dimensional infinite chains.The structural difference is that 1 is a double-chain structure and 2 is only a single chain one.At the same time,the carboxylate groups adopt different modes in the two compounds,relatively.Additionally,in order to explore the structural characteristic,two-dimen-sional IR spectra are investigated for 1 and 2.Photo-luminescent property of 2 is also researched in detail.展开更多
Recently, modifications of charge density wave(CDW) in two-dimensional(2D) show intriguing properties in quasi-2D materials such as layered transition metal dichalcogenides(TMDCs). Optical, electrical transport ...Recently, modifications of charge density wave(CDW) in two-dimensional(2D) show intriguing properties in quasi-2D materials such as layered transition metal dichalcogenides(TMDCs). Optical, electrical transport measurements and scanning tunneling microscopy uncover the enormous difference on the many-body states when the thickness is reduced down to monolayer. However, the CDW in quasi-one-dimensional(1D) materials like transition metal trichalcogenides(TMTCs) is yet to be explored in low dimension whose mechanism is likely distinct from their quasi-2D counterparts.Here, we report a systematic study on the CDW properties of titanium trisulfide(TiS3). Two phase transition temperatures were observed to decrease from 53 K(103 K) to 46 K(85 K) for the bulk and 〈 15-nm thick nanoribbon, respectively,which arises from the increased fluctuation effect across the chain in the nanoribbon structure, thereby destroying the CDW coherence. It also suggests a strong anisotropy of CDW states in quasi-1D TMTCs which is different from that in TMDCs.Remarkably, by using back gate of-30 V ~ 70 V in 15-nm device, we can tune the second transition temperature from110 K(at-30 V) to 93 K(at 70 V) owing to the altered electron concentration. Finally, the optical approach through the impinging of laser beams on the sample surface is exploited to manipulate the CDW transition, where the melting of the CDW states shows a strong dependence on the excitation energy. Our results demonstrate TiS3 as a promising quasi-1D CDW material and open up a new window for the study of collective phases in TMTCs.展开更多
The two-dimensional electron gas at SrTiO3-based heterointerfaces has received a great deal of attention in recent years owing to their potential for the exploration of emergent physics and the next generation of elec...The two-dimensional electron gas at SrTiO3-based heterointerfaces has received a great deal of attention in recent years owing to their potential for the exploration of emergent physics and the next generation of electronics. One of the most fascinating aspects in this system is that the light, as a powerful external perturbation, can modify its transport properties. Recent studies have reported that SrTiO3-based heterointerfaces exhibit the persistent photoconductivity and can be tuned by the surface and interface engineering. These researches not only reveal the intrinsic physical mechanisms in the photoresponsive process, but also highlight the ability to be used as a tool for novel all-oxide optical devices. This review mainly contraposes the studies of photoresponse at SrTiO3-based heterointerfaces.展开更多
Due to many remarkable physical and chemical properties, two-dimensional(2D) nanomaterials have become a hot spot in the field of condensed matter physics. In this paper, we have studied the structural, mechanical, an...Due to many remarkable physical and chemical properties, two-dimensional(2D) nanomaterials have become a hot spot in the field of condensed matter physics. In this paper, we have studied the structural, mechanical, and electronic properties of the 2D GaInO_3 system by first-principles method. We find that 2D Ga InO_3 can exist stably at ambient condition. Molecular dynamic simulations show that GaInO_3-sheet has excellent thermal stability and is stable up to1100 K. Electronic structural calculations show that GaInO_3-sheet has a band gap of 1.56 eV, which is close to the ideal band gap of solar cell materials, demonstrating great potential in future photovoltaic application. In addition, strain effect studies show that the GaInO_3-sheet structure always exhibits a direct band gap under biaxial compressive strain, and as the biaxial compressive strain increases, the band gap gradually decreases until it is converted into metal. While biaxial tensile strain can cause the 2D material to transform from a direct band gap semiconductor into an indirect band gap semiconductor,and even to metal. Our research expands the application of the Ga InO_3 system, which may have potential application value in electronic devices and solar energy.展开更多
The first-principles calculations are employed to investigate the stability, magnetic, and electrical properties of the oxide heterostructure of LaAIO3/SrTiO3 (110). By comparing their interface energies, it is obta...The first-principles calculations are employed to investigate the stability, magnetic, and electrical properties of the oxide heterostructure of LaAIO3/SrTiO3 (110). By comparing their interface energies, it is obtained that the buckled interface is more stable than the abrupt interface. This result is consistent with experimental observation. At the interface of LaAIO3/SrTiO3 (110) heterostructure, the Ti-O octahedron distortions cause the Ti tzg orbitals to split into the two- fold degenerate dxz/dyz and nondegenerate dxy orbitals. The former has higher energy than the latter. The partly filled two-fold degenerate t2g orbitals are the origin of two-dimensional electron gas, which is confined at the interface. Lattice mismatch between LaA103 and SrTiO3 leads to ferroelectric-like lattice distortions at the interface, and this is the origin of spin-splitting of Ti 3d electrons. Hence the magnetism appears at the interface of LaAIO3/SrTiO3 (110).展开更多
The manufacturing of three-dimensional textile preforms used for composites started to re-ceive much attention in the last decade.The major barriers to accelerating the transition from thelamination of two-dimensional...The manufacturing of three-dimensional textile preforms used for composites started to re-ceive much attention in the last decade.The major barriers to accelerating the transition from thelamination of two-dimensional fabrics to manufacturing integral three-dimensional near-netshaped textile preforms are high cost and database deficiency.To reduce the cost of weaving three-dimensional preforms,and make full use of the potential of conventional looms,a rig was designedwhich can convert two-dimensional woven fabric to particular three-dimensional preforms wherethe yarn is orientated in the directions of maximum stress.展开更多
Two-dimensional(2D)magnets provide an ideal platform to explore new physical phenomena in fundamental magnetism and to realize the miniaturization of magnetic devices.The study on its domain structure evolution with t...Two-dimensional(2D)magnets provide an ideal platform to explore new physical phenomena in fundamental magnetism and to realize the miniaturization of magnetic devices.The study on its domain structure evolution with thickness is of great significance for better understanding the 2D magnetism.Here,we investigate the magnetization reversal and domain structure evolution in 2D ferromagnet Fe_(3)GeTe_(2)(FGT)with a thickness range of 11.2-112 nm.Three types of domain structures and their corresponding hysteresis loops can be obtained.The magnetic domain varies from a circular domain via a dendritic domain to a labyrinthian domain with increasing FGT thickness,which is accompanied by a transition from squared to slanted hysteresis loops with reduced coercive fields.These features can be ascribed to the total energy changes from exchange interaction-dominated to dipolar interaction-dominated with increasing FGT thickness.Our finding not only enriches the fundamental magnetism,but also paves a way towards spintronics based on 2D magnet.展开更多
The replacement of small cations with bulkier organic cations containing long alkyl chains or benzene rings to form a thin two-dimensional(2D)perovskite passivation layer on three-dimensional(3D)perovskite(2D/3D)has b...The replacement of small cations with bulkier organic cations containing long alkyl chains or benzene rings to form a thin two-dimensional(2D)perovskite passivation layer on three-dimensional(3D)perovskite(2D/3D)has become a promising strategy for improving both the efficiency and stability of perovskite solar cells(PSCs).The 2 D layer defines the interfacial chemistry and physics at the 2D/3D bilayer and endows the 2D/3D structure with better chemical and thermal stability.Herein,2D/3D(CF_(3)-PEA)_(2) FA_(0.85)MA_(0.15)Pb_(2)I_(7)/FA_(0.85)MA_(0.15)PbI_(3) planar heterojunction perovskite was produced using a facile interfacial ion exchange process.The 2 D(CF_(3)-PEA)_(2) FA_(0.85)MA_(0.15)Pb_(2)I_(7) capping layer can not only passivate the FA_(0.85)MA_(0.15)PbI_(3) film but also act as super-hydrophobic layer to inhibit water diffusion and significantly enhance the stability.The 2D capping layer can also establish a unique graded band structure at the perovskite/Spiro-OMeTAD interface and lead to p-type doping for Spiro-OMeTAD layer which is beneficial for efficient charge transport.Optimized PSCs based on this 2D/3D heterojunction yield a champion power conversion efficiency(PCE)of 23.1%and improved stability.The device maintains 84%output for 2400 h aging under ambient environmental conditions without encapsulation,and maintains 81%for 200 h under illumination with encapsulation.This work will inspire the design of more fluorinated 2D perovskite interfaces for advanced photovoltaics and beyond.展开更多
Recently, the quasi-two-dimensional electron gas (q2DEG) confined at the interface between LaAlO3 and SrTiO3 has attracted significant attention. In this paper, we briefly review experimental methods that have been ...Recently, the quasi-two-dimensional electron gas (q2DEG) confined at the interface between LaAlO3 and SrTiO3 has attracted significant attention. In this paper, we briefly review experimental methods that have been used to tune the carrier density and mobility of this q2DEG. These methods can be classified into two categories: growth-related tuning (i.e. substrate, growth temperature, oxygen pressure, post-annealing, LaAlO3 thickness, stoichiometry, and capping layers) and post-growth tuning (i.e. electrostatic field gating, conductive atomic force microscopy and surface adsorbates). Taken together, these methods enable the broad tuning of the electronic properties of this interface.展开更多
基金Shenzhen Basic Research Project of Science and Technology(JCYJ20150324141711581,JCYJ20170302142433007)Postgraduate Innovation Development Fund Project of Shenzhen University(PIDFPZR2018007)
文摘We have studied the two-and three-photon absorption(2PA and 3PA) properties of Mn-doped CsPbCl_3 twodimensional nanoplatelets(2D NPs) and cubic nanocrystals. Compared with their cubic counterparts, the Mn-doped 2D NPs exhibit stronger quantum confinement effects that can more efficiently enhance their dopantcarrier exchange interactions and multiphoton absorption. More specifically, the maximum volume-normalized 2PA and 3PA cross sections of the 2D NPs were 6.8 and 7.2 times greater than those of their cubic counterparts,respectively, reaching up to 1237 GM∕nm^3 in the visible light band and 2.24 × 10^(-78) cm^6· s^2· photon^(-2)∕nm^3 in the second biological window, respectively.
基金This research was financially supported by National Natural Science Foundation of China (40206022).
文摘Two-dimensional electrophoresis(2-DE) of protein extracted and purified from Alexandrium sp. LC3 was conducted. In the SDS-PAGE study, the relative molecular weights of the proteins were mainly in the range of 14 kDa-31 kDa and 43 kDa-66 kDa, and more proteins were detected between 14kDa and 31 kDa. With the improved protein preparation, the two-dimensional electrophoresis patterns indicated that the relative molecular weights of the proteins were between 14kDa and 100kDa, and most of them ranged from 14 kDa to 31 kDa. This was consistent with the result of the SDS-PAGE analysis. The isoelectric points were found to lie between 3.0 and 8.0, and most of them were in the range of 3.0-6.0. Better separation effect was acquired with pre-prepared immobilized gradient (IPG) strip (pH 3-5.6), and about 320 protein spots could be visualized on the 2-DE map by staining. Within pH 3-l0 and pH 3-5.6 strips, the protein samples of Alexandrium sp. LC3 could be separated well.
基金supported by the National Basic Research Program of China(Grant No.2013CB632506)the National Natural Science Foundation of China(Grant Nos.11374186,51231007,51202132,and 51102153)the Independent Innovation Foundation of Shandong University,China(Grant No.2012TS027)
文摘The first-principles calculations are employed to investigate the electrical properties of polar MgO/BaTiO3(110)interfaces. Both n-type and p-type polar interfaces show a two-dimensional metallic behavior. For the n-type polar interface,the interface Ti3d electrons are the origin of the metallic and magnetic properties. Varying the thickness of Ba TiO3 may induce an insulator–metal transition, and the critical thickness is 4 unit cells. For the p-type polar interface, holes preferentially occupy the interface O 2p y state, resulting in a conducting interface. The unbalance of the spin splitting of the O 2p states in the interface Mg O layer leads to a magnetic moment of about 0.25μB per O atom at the interface.These results further demonstrate that other polar interfaces, besides LaAlO3/SrTiO3, can show a two-dimensional metallic behavior. It is helpful to fully understand the role of polar discontinuity on the properties of the interface, which widens the field of polar-nonpolar interfaces.
基金support from the National Natural Science Foundation of China(21673087 and 21873032)startup fund(2006013118 and 3004013105)from Huazhong University of Science and Technologythe Fundamental Research Funds for the Central Universities(2019kfy R CPY116)
文摘Organometallic nanosheets are a versatile platform for design of efficient electrocatalyst materials due to their high surface area and uniform dispersion of metal active sites.In this paper,we systematically investigate the electrocatalytic performance of the first transition metal series TM3–C12S12 monolayers on CO2 using spin-polarized density functional theory.The calculations show that M3–C12S12 exhibits excellent catalytic activity and selectivity in the catalytic reduction in CO2.The main reduction products of Sc,Ti,and Cr are CH4.V,Mn,Fe and Zn mainly produce HCOOH,and Co produces HCHO,while CO is the main product for Ni and Cu.For Sc,Ti,and Cr,the overpotentials are>0.7 V,while for V,Mn,Fe,Co,Ni,Cu,Zn,the overpotentials are very low and range from 0.27 to 0.47 V.Therefore,our results indicate that many of the M3–C12S12 monolayers are expected to be excellent and efficient CO2 reduction catalysts.
基金supported by National Natural Science Foundation of China(Nos.61774003,61521004,51472080)National Key Research and Development Program of China(Nos.2017YFA0205700,2017YFA0304600)+1 种基金Open Research Fund Program of the State Key Laboratory of Low-dimensional Quantum Physics(No.KF201706)Excellent Youth Foundation of Hubei Province(No.2017CFA038)
文摘Fabricating high-quality cesium lead chloride(CsPbCl_3) perovskite nanowires(NWs) with dimension below 10 nm is not only of interests in fundamental physics, but also holds the great promise for optoelectronic applications. Herein, ultrathin CsPbCl_3 NWs with height of ~7 nm, have been achieved via vapor phase deposition method. Power and temperature-dependent photoluminescence(PL) spectroscopy is performed to explore the emission properties of the CsPbCl_3 NWs. Strong free exciton recombination is observed at ~3.02 eV as the temperature(T) is 78-294 K with binding energy of ~ 37.5 meV. With the decreasing of T, the PL peaks exhibit a first blueshift by 2 meV for T ~ 294-190 K and then a redshift by 4 meV for T ~ 190-78 K. The exciton–optical phonon interaction plays a major role in the linewidth broadening of the PL spectra with average optical phonon energy of ~48.0 meV and the interaction coefficient of 203.9 meV. These findings advance the fabrication of low dimensional CsPbCl_3 perovskite and provide insights into the photophysics of the CsPbCl_3 perovskite.
文摘Our recent experimental work on metallic and insulating interfaces controlled by interfacial redox reactions in SrTiO3-based heterostructures is reviewed along with a more general background of two-dimensional electron gas (2DEG) at oxide interfaces. Due to the presence of oxygen vacancies at the SrTiO3 surface, metallic conduction can be created at room temperature in perovskite-type interfaces when the overlayer oxide ABO3 has Al, Ti, Zr, or Hf elements at the B sites. Furthermore, relying on interface-stabilized oxygen vacancies, we have created a new type of 2DEG at the heterointerface between SrTiO3 and a spinel γ-Al2O3 epitaxial film with compatible oxygen ion sublattices. This 2DEG exhibits an electron mobility exceeding 100000 cm2·V-1·s-1, more than one order of magnitude higher than those of hitherto investigated perovskite-type interfaces. Our findings pave the way for the design of high-mobility all-oxide electronic devices and open a route toward the studies of mesoscopic physics with complex oxides.
基金the financial support of the National Natural Science Foundation of China (No. 21878118)Natural Science Foundation of the Jiangsu Higher Education Institutions of China (21KJA530002, 19KJA150009)+1 种基金Natural Science Foundation of Jiangsu Province (BK20211368)Jiangsu Province Qing Lan Project for the Young Academic Leaders (Meisheng Li, 2021)
文摘Recent years,membrane separation technology has attracted significant research attention because of the efficient and environmentally friendly operation.The selection of suitable materials to improve the membrane selectivity,permeability and other properties has become a topic of vital research relevance.Two-dimensional(2D)materials,a novel family of multifunctional materials,are widely used in membrane separation due to their unique structure and properties.In this respect,as a novel 2D material,graphitic carbon nitride(g-C_(3)N_(4))have found specific attention in membrane separation.This study reviews the application of carbon nitride in gas separation membranes,pervaporation membranes,nanofiltration membranes,reverse osmosis membranes,ion exchange membranes and catalytic membranes,along with describing the separation mechanisms.
文摘In recent years, with the level of science and technology progress, largely to promote the development of animation techniques. Animated film is divided into two-dimensional animation and three-dimensional animation, both in the retention feature animated films, based on the performance of each with different strengths, thus forming a different artistic style. Wherein the two-dimensional animation is the most common one is the most basic form of expression in animation technology is relatively mature and complete, but because of the development of animation techniques, two-dimensional animation can not meet the needs of the audience. Thus, the effective combination of two-dimensional animation and three-dimensional animation technology, the advantages of integration between the two is particularly important, so that innovation in the form of screen performance, enhance audio-visual experience. In this paper, two-dimensional animation and three-dimensional animation skills fusion analysis and research, and put forward a number of specific observations, in order to learn.
基金supported by the National Natural Science Foundation of China(No.52272136)the Natural Science Foundation of Jiangsu Province(No.BK20221402)the China Postdoctoral Science Foundation(No.2022M712322)。
文摘For the first time,we report high-performance two-dimensional(2D)perovskite Pb_(2)Nb_(3)O_(10) photodetectors(PNO PDs).The few-layer PNO nanosheets are obtained successfully through a simple calcination and liquid exfoliation method.The individual PNO nanosheet devices with various structures(Au-PNO-Au,Au-PNO-Ti,Ti-PNO-Ti)are fabricated and investigated.The Au-PNO-Ti device exhibits a high rectification factor(∼102)owing to a large Schottky barrier difference between the PNO nanosheet and two asymmetric electrodes.Notably,the Au-PNO-Ti device shows excellent self-powered performance,including high responsivity(2.8 A/W),high detectivity(1.1×10^(12) Jones),and fast speed(0.2/1.2 ms)at 350 nm light illumination.This work not only suggests the performance of the PNO nanosheet PDs but also sheds light on the development of high-stability and high-performance devices based on 2D perovskite niobate in the future.
基金supported by the National Aeronautics and Space Administration under grant number 80NSSC20K0352.
文摘An improved algorithm for computing multiphase flows is presented in which the multimaterial Moment-of-Fluid(MOF)algorithm for multiphase flows,initially described by Li et al.(2015),is enhanced addressing existing MOF difficulties in computing solutions to problems in which surface tension forces are crucial for understanding salient flow mechanisms.The Continuous MOF(CMOF)method is motivated in this article.The CMOF reconstruction method inherently removes the"checkerboard instability"that persists when using the MOF method on surface tension driven multiphase(multimaterial)flows.The CMOF reconstruction algorithm is accelerated by coupling the CMOF method to the level set method and coupling the CMOF method to a decision tree machine learning(ML)algorithm.Multiphase flow examples are shown in the two-dimensional(2D),three-dimensional(3D)axisymmetric"RZ",and 3D coordinate systems.Examples include two material and three material multiphase flows:bubble formation,the impingement of a liquid jet on a gas bubble in a cryogenic fuel tank,freezing,and liquid lens dynamics.
基金supported by the National Natural Science Foundation of China (No. 20873021,21003020)New Century Excellent Talent Supported Plan of Fujian Province (SXSJRC2007-21)
文摘Two compounds with 3-methylbenzoic acid(HL) [Co(L)2(4,4'-bipy)]n 1 and [Zn2(L)4(4,4'-bipy)]n 2(L = 3-methylbenzoic acid) have been hydrothermally synthesized directly and characterized by single-crystal X-ray diffraction analysis,elemental analyses,IR spectra and ultraviolet-visible diffuse reflection integral spectra(UV-Vis DRIS).The two compounds are both one-dimensional infinite chains.The structural difference is that 1 is a double-chain structure and 2 is only a single chain one.At the same time,the carboxylate groups adopt different modes in the two compounds,relatively.Additionally,in order to explore the structural characteristic,two-dimen-sional IR spectra are investigated for 1 and 2.Photo-luminescent property of 2 is also researched in detail.
基金Project supported by the National Young 1000-Talent Planthe National Natural Science Foundation of China(Grant Nos.61322407,11474058,and61674040)
文摘Recently, modifications of charge density wave(CDW) in two-dimensional(2D) show intriguing properties in quasi-2D materials such as layered transition metal dichalcogenides(TMDCs). Optical, electrical transport measurements and scanning tunneling microscopy uncover the enormous difference on the many-body states when the thickness is reduced down to monolayer. However, the CDW in quasi-one-dimensional(1D) materials like transition metal trichalcogenides(TMTCs) is yet to be explored in low dimension whose mechanism is likely distinct from their quasi-2D counterparts.Here, we report a systematic study on the CDW properties of titanium trisulfide(TiS3). Two phase transition temperatures were observed to decrease from 53 K(103 K) to 46 K(85 K) for the bulk and 〈 15-nm thick nanoribbon, respectively,which arises from the increased fluctuation effect across the chain in the nanoribbon structure, thereby destroying the CDW coherence. It also suggests a strong anisotropy of CDW states in quasi-1D TMTCs which is different from that in TMDCs.Remarkably, by using back gate of-30 V ~ 70 V in 15-nm device, we can tune the second transition temperature from110 K(at-30 V) to 93 K(at 70 V) owing to the altered electron concentration. Finally, the optical approach through the impinging of laser beams on the sample surface is exploited to manipulate the CDW transition, where the melting of the CDW states shows a strong dependence on the excitation energy. Our results demonstrate TiS3 as a promising quasi-1D CDW material and open up a new window for the study of collective phases in TMTCs.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51572222 and 11604265)Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,China(Grant No.CX201836)
文摘The two-dimensional electron gas at SrTiO3-based heterointerfaces has received a great deal of attention in recent years owing to their potential for the exploration of emergent physics and the next generation of electronics. One of the most fascinating aspects in this system is that the light, as a powerful external perturbation, can modify its transport properties. Recent studies have reported that SrTiO3-based heterointerfaces exhibit the persistent photoconductivity and can be tuned by the surface and interface engineering. These researches not only reveal the intrinsic physical mechanisms in the photoresponsive process, but also highlight the ability to be used as a tool for novel all-oxide optical devices. This review mainly contraposes the studies of photoresponse at SrTiO3-based heterointerfaces.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11847094,61764001,and U1404212)the Cheung Kong Scholars Programme of China+2 种基金the Program of Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT1132)Open Project of State Key Laboratory of Superhard Materials(Jilin University)China(Grant No.201703)
文摘Due to many remarkable physical and chemical properties, two-dimensional(2D) nanomaterials have become a hot spot in the field of condensed matter physics. In this paper, we have studied the structural, mechanical, and electronic properties of the 2D GaInO_3 system by first-principles method. We find that 2D Ga InO_3 can exist stably at ambient condition. Molecular dynamic simulations show that GaInO_3-sheet has excellent thermal stability and is stable up to1100 K. Electronic structural calculations show that GaInO_3-sheet has a band gap of 1.56 eV, which is close to the ideal band gap of solar cell materials, demonstrating great potential in future photovoltaic application. In addition, strain effect studies show that the GaInO_3-sheet structure always exhibits a direct band gap under biaxial compressive strain, and as the biaxial compressive strain increases, the band gap gradually decreases until it is converted into metal. While biaxial tensile strain can cause the 2D material to transform from a direct band gap semiconductor into an indirect band gap semiconductor,and even to metal. Our research expands the application of the Ga InO_3 system, which may have potential application value in electronic devices and solar energy.
基金Project supported by the National Basis Research Program of China(Grant No.2013CB632506)the National Natural Science Foundation of China(Grant Nos.11374186,51231007,and 51202132)the Independent Innovation Foundation of Shandong University,China(Grant No.2012TS027)
文摘The first-principles calculations are employed to investigate the stability, magnetic, and electrical properties of the oxide heterostructure of LaAIO3/SrTiO3 (110). By comparing their interface energies, it is obtained that the buckled interface is more stable than the abrupt interface. This result is consistent with experimental observation. At the interface of LaAIO3/SrTiO3 (110) heterostructure, the Ti-O octahedron distortions cause the Ti tzg orbitals to split into the two- fold degenerate dxz/dyz and nondegenerate dxy orbitals. The former has higher energy than the latter. The partly filled two-fold degenerate t2g orbitals are the origin of two-dimensional electron gas, which is confined at the interface. Lattice mismatch between LaA103 and SrTiO3 leads to ferroelectric-like lattice distortions at the interface, and this is the origin of spin-splitting of Ti 3d electrons. Hence the magnetism appears at the interface of LaAIO3/SrTiO3 (110).
文摘The manufacturing of three-dimensional textile preforms used for composites started to re-ceive much attention in the last decade.The major barriers to accelerating the transition from thelamination of two-dimensional fabrics to manufacturing integral three-dimensional near-netshaped textile preforms are high cost and database deficiency.To reduce the cost of weaving three-dimensional preforms,and make full use of the potential of conventional looms,a rig was designedwhich can convert two-dimensional woven fabric to particular three-dimensional preforms wherethe yarn is orientated in the directions of maximum stress.
基金Project supported by the National Key R&D Program of China(Grant Nos.2017YFA0206202 and 2019YFA0308000)the National Natural Science Foundation of China(Grant Nos.51871130,62022089,and 11874405)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2019007)。
文摘Two-dimensional(2D)magnets provide an ideal platform to explore new physical phenomena in fundamental magnetism and to realize the miniaturization of magnetic devices.The study on its domain structure evolution with thickness is of great significance for better understanding the 2D magnetism.Here,we investigate the magnetization reversal and domain structure evolution in 2D ferromagnet Fe_(3)GeTe_(2)(FGT)with a thickness range of 11.2-112 nm.Three types of domain structures and their corresponding hysteresis loops can be obtained.The magnetic domain varies from a circular domain via a dendritic domain to a labyrinthian domain with increasing FGT thickness,which is accompanied by a transition from squared to slanted hysteresis loops with reduced coercive fields.These features can be ascribed to the total energy changes from exchange interaction-dominated to dipolar interaction-dominated with increasing FGT thickness.Our finding not only enriches the fundamental magnetism,but also paves a way towards spintronics based on 2D magnet.
基金support from the National Natural Science Foundation of China(62074095)the National Key Research and Development Program of China(2016YFA0202403)+3 种基金the Fundamental Research Funds for the Central Universities(GK202002001)the 111 Project B(14041)the DNL Cooperation Fund CAS(DNL180311)support of the H2 cluster in Xi’an Jiaotong University。
文摘The replacement of small cations with bulkier organic cations containing long alkyl chains or benzene rings to form a thin two-dimensional(2D)perovskite passivation layer on three-dimensional(3D)perovskite(2D/3D)has become a promising strategy for improving both the efficiency and stability of perovskite solar cells(PSCs).The 2 D layer defines the interfacial chemistry and physics at the 2D/3D bilayer and endows the 2D/3D structure with better chemical and thermal stability.Herein,2D/3D(CF_(3)-PEA)_(2) FA_(0.85)MA_(0.15)Pb_(2)I_(7)/FA_(0.85)MA_(0.15)PbI_(3) planar heterojunction perovskite was produced using a facile interfacial ion exchange process.The 2 D(CF_(3)-PEA)_(2) FA_(0.85)MA_(0.15)Pb_(2)I_(7) capping layer can not only passivate the FA_(0.85)MA_(0.15)PbI_(3) film but also act as super-hydrophobic layer to inhibit water diffusion and significantly enhance the stability.The 2D capping layer can also establish a unique graded band structure at the perovskite/Spiro-OMeTAD interface and lead to p-type doping for Spiro-OMeTAD layer which is beneficial for efficient charge transport.Optimized PSCs based on this 2D/3D heterojunction yield a champion power conversion efficiency(PCE)of 23.1%and improved stability.The device maintains 84%output for 2400 h aging under ambient environmental conditions without encapsulation,and maintains 81%for 200 h under illumination with encapsulation.This work will inspire the design of more fluorinated 2D perovskite interfaces for advanced photovoltaics and beyond.
基金Project supported by the Department of Energy,Office of Basic Energy Sciences(Grant No.DE-AC02-76SF00515)
文摘Recently, the quasi-two-dimensional electron gas (q2DEG) confined at the interface between LaAlO3 and SrTiO3 has attracted significant attention. In this paper, we briefly review experimental methods that have been used to tune the carrier density and mobility of this q2DEG. These methods can be classified into two categories: growth-related tuning (i.e. substrate, growth temperature, oxygen pressure, post-annealing, LaAlO3 thickness, stoichiometry, and capping layers) and post-growth tuning (i.e. electrostatic field gating, conductive atomic force microscopy and surface adsorbates). Taken together, these methods enable the broad tuning of the electronic properties of this interface.