Multiferroic tunnel junctions(MFTJs),which combine tunneling magnetoresistance(TMR)and electroresistance(TER)efects,have emerged as key candidates for data storage.Two-dimensional van der Waals(vdW)MFTJs,in particular...Multiferroic tunnel junctions(MFTJs),which combine tunneling magnetoresistance(TMR)and electroresistance(TER)efects,have emerged as key candidates for data storage.Two-dimensional van der Waals(vdW)MFTJs,in particular,are promising spintronic devices for the post-Moore era.However,these vdW MFTJs are typically based on multiferroics composed of ferromagnetic and ferroelectric materials or multilayer magnetic materials with sliding ferroelectricity,which increases device fabrication complexity.In this work,we design a vdW MFTJ using bilayer MoPtGe_(2)S_(6),a material with homologous multiferroicity in each monolayer,combined with symmetric PtTe_(2)electrodes.Using frst-principles calculations based on density functional theory and nonequilibrium Green's functions,we theoretically explore the spin-polarized electronic transport properties of this MFTJ.By controlling the ferroelectric and ferromagnetic polarization directions of bilayer MoPtGe_(2)S_(6),the MFTJ can exhibit six distinct non-volatile resistance states,with maximum TMR(137%)and TER(1943%)ratios.Under biaxial strain,TMR and TER can increase to 265%and 4210%,respectively.The TER ratio also increases to 2186%under a 0.1 V bias voltage.Remarkably,the MFTJ exhibits a pronounced spin-fltering and a signifcant negative diferential resistance efect.These fndings not only highlight the potential of monolayer multiferroic MoPtGe_(2)S_(6)for MFTJs but also ofer valuable theoretical insights for future experimental investigations.展开更多
The stable nanobubbles adhered to mineral surfaces may facilitate their efficient separation via flotation in the mining industry.However,the state of nanobubbles on mineral solid surfaces is still elusive.In this stu...The stable nanobubbles adhered to mineral surfaces may facilitate their efficient separation via flotation in the mining industry.However,the state of nanobubbles on mineral solid surfaces is still elusive.In this study,molecular dynamics(MD)simulations are employed to examine mineral-like model surfaces with varying degrees of hydrophobicity,modulated by surface charges,to elucidate the adsorption behavior of nanobubbles at the interface.Our findings not only contribute to the fundamental understanding of nanobubbles but also have potential applications in the mining industry.We observed that as the surface charge increases,the contact angle of the nanobubbles increases accordingly with shape transformation from a pancake-like gas film to a cap-like shape,and ultimately forming a stable nanobubble upon an ordered water monolayer.When the solid–water interactions are weak with a small partial charge,the hydrophobic gas(N_(2))molecules accumulate near the solid surfaces.However,we have found,for the first time,that gas molecules assemble a nanobubble on the water monolayer adjacent to the solid surfaces with large partial charges.Such phenomena are attributed to the formation of a hydrophobic water monolayer with a hydrogen bond network structure near the surface.展开更多
High-resolution transmission electron microscopy(HRTEM)promises rapid atomic-scale dynamic structure imaging.Yet,the precision limitations of aberration parameters and the challenge of eliminating aberrations in Cs-co...High-resolution transmission electron microscopy(HRTEM)promises rapid atomic-scale dynamic structure imaging.Yet,the precision limitations of aberration parameters and the challenge of eliminating aberrations in Cs-corrected transmission electron microscopy constrain resolution.A machine learning algorithm is developed to determine the aberration parameters with higher precision from small,lattice-periodic crystal images.The proposed algorithm is then validated with simulated HRTEM images of graphene and applied to the experimental images of a molybdenum disulfide(MoS_(2))monolayer with 25 variables(14 aberrations)resolved in wide ranges.Using these measured parameters,the phases of the exit-wave functions are reconstructed for each image in a focal series of MoS_(2)monolayers.The images were acquired due to the unexpected movement of the specimen holder.Four-dimensional data extraction reveals time-varying atomic structures and ripple.In particular,the atomic evolution of the sulfur-vacancy point and line defects,as well as the edge structure near the amorphous,is visualized as the resolution has been improved from about 1.75?to 0.9 A.This method can help salvage important transmission electron microscope images and is beneficial for the images obtained from electron microscopes with average stability.展开更多
A redox-active monolayer on an optically transparent electrode constitutes a typical platform for spectroelectrochemical sensing.The necessity for its sophistication arises from the availability of multi-dimensional s...A redox-active monolayer on an optically transparent electrode constitutes a typical platform for spectroelectrochemical sensing.The necessity for its sophistication arises from the availability of multi-dimensional sensing signals.Simultaneous monitoring of the redox current and color change synchronized with the oxidation state change significantly enhances sen-sitivity and selectivity.This study aimed to elucidate the modification of an indium tin oxide(ITO)electrode with a viologen monolayer with an ordered orientation.Novel methods were developed to immobilize a viologen molecule bearing a car-boxyl group to form assembled monolayers through a condensation reaction using 1-ethyl-3-(3-dimethylaminopropyl)-car-bodiimide with N-hydroxy-succinimide(EDC/NHS).In the two methods of immobilization,one utilizes a two-step process to firstly form an aromatic siloxane base layer and subsequently attach the viologen derivative through an amide linkage by post-amidation.The other employs a direct ester linkage between the hydroxyl groups of the ITO surface and the car-boxyl group of the viologen derivative.The latter method was also applied to immobilize a ferrocenyl group at a very short distance from the ITO surface.Potential-modulated UV-visible transmission absorption spectral measurement techniques with oblique incidence of plane-polarized light were employed to determine the orientation of the longitudinal axis of the reduced form of the viologen.The frequency dependence data of the potential-modulated transmission absorption signals were utilized to analyze the electron transfer kinetics.The performance of the two viologen-modified electrodes was com-pared to that of an ITO modified by post-amidation to the most commonly used base layer prepared with 3-aminopropyl triethoxysilane.展开更多
Monolayer CrI_(3),crystalizing in the P31m space group,is a prototypical two-dimensional(2D)material for observing intrinsic ferromagnetic order.However,its relatively low Curie temperature(T_(C))of 45 K severely limi...Monolayer CrI_(3),crystalizing in the P31m space group,is a prototypical two-dimensional(2D)material for observing intrinsic ferromagnetic order.However,its relatively low Curie temperature(T_(C))of 45 K severely limits its practical applications,highlighting the need to explore novel metastable polymorphs with enhanced magnetic properties.In this study,we employ a global crystal structure search technique combined with first-principles calculations to systematically investigate new monolayer CrI_(3)phases.Our structural predictions identify two novel polymorphs with Cm and P2/m space groups,both of which are dynamically stable and exhibit significantly higher T_(C)values of 145 K and 81 K,respectively.Electronic property calculations show that the Cm phase is a half-metal,while the P2/m phase is semiconducting with a bandgap of 0.14 eV.Monte Carlo simulations attribute these enhanced T_(C)values to a notable increase in exchange interactions.These findings expand the known phase space of CrI_(3)and provide a promising pathway for designing hightemperature 2D ferromagnets for next-generation spintronic applications.展开更多
Self-assembled monolayers(SAMs)are widely used as hole transport materials in inverted perovskite solar cells,offering low parasitic absorption and suitability for semitransparent and tandem solar cells.While SAMs hav...Self-assembled monolayers(SAMs)are widely used as hole transport materials in inverted perovskite solar cells,offering low parasitic absorption and suitability for semitransparent and tandem solar cells.While SAMs have shown to be promising in small-area devices(≤1 cm^(2)),their application in larger areas has been limited by a lack of knowledge regarding alternative deposition methods beyond the common spin-coating approach.Here,we compare spin-coating and upscalable methods such as thermal evaporation and spray-coating for[2-(9H-carbazol-9-yl)ethyl]phosphonic acid(2PACz),one of the most common carbazole-based SAMs.The impact of these deposition methods on the device performance is investigated,revealing that the spray-coating technique yields higher device performance.Furthermore,our work provides guidelines for the deposition of SAM materials for the fabrication of perovskite solar modules.In addition,we provide an extensive characterization of 2PACz films focusing on thermal evaporation and spray-coating methods,which allow for thicker 2PACz deposition.It is found that the optimal 2PACz deposition conditions corresponding to the highest device performances do not always correlate with the monolayer characteristics.展开更多
Establishing the structure-property relationship in amorphous materials has been a long-term grand challenge due to the lack of a unified description of the degree of disorder.In this work,we develop SPRamNet,a neural...Establishing the structure-property relationship in amorphous materials has been a long-term grand challenge due to the lack of a unified description of the degree of disorder.In this work,we develop SPRamNet,a neural network based machine-learning pipeline that effectively predicts structure-property relationship of amorphous material via global descriptors.Applying SPRamNet on the recently discovered amorphous monolayer carbon,we successfully predict the thermal and electronic properties.More importantly,we reveal that a short range of pair correlation function can readily encode sufficiently rich information of the structure of amorphous material.Utilizing powerful machine learning architectures,the encoded information can be decoded to reconstruct macroscopic properties involving many-body and long-range interactions.Establishing this hidden relationship offers a unified description of the degree of disorder and eliminates the heavy burden of measuring atomic structure,opening a new avenue in studying amorphous materials.展开更多
The competition between dimensionality and ordering in multiferroic materials is of great interest for both fundamental physics and potential applications. Combining first-principles calculations with micromagnetic si...The competition between dimensionality and ordering in multiferroic materials is of great interest for both fundamental physics and potential applications. Combining first-principles calculations with micromagnetic simulations, we investigate recently synthesized ultrathin perovskite bismuth ferrite(BFO) films. Our numerical results reveal that, at the monolayer limit, the ferroelectricity of BFO is missing because the octahedral distortions are constrained. However, the monolayer bismuth ferrite is a topological antiferromagnetic metal with tunable bimeron magnetic structure. The dual topologically non-trivial characteristics make monolayer bismuth ferrite a multifunctional building block in future spintronic devices.展开更多
Exploring earth-abundant,highly active bifunctional electrocatalysts for efficient hydrogen and oxygen evolution is crucial for water splitting.However,due to their distinct free energies and conducting behaviors(elec...Exploring earth-abundant,highly active bifunctional electrocatalysts for efficient hydrogen and oxygen evolution is crucial for water splitting.However,due to their distinct free energies and conducting behaviors(electron/hole),balancing the catalytic efficiency between hydrogen and oxygen evolution remains challenging for achieving bifunctional electrocatalysts.Here,we report a locally-doped MoS_(2)monolayer with an in-plane heterostructure acting as a bifunctional electrocatalyst and apply it to the overall water splitting.In this heterostructure,the core region contains Mo/S vacancies,while the ring region was doped by Fe atoms(in two substitution configurations:1FeMo and 3FeMo-VS clusters)with a p-type conductive characteristic.Our micro-cell measurements,combined with density functional theory(DFT)calculations,reveal that the vacancies-rich core region presents remarkable hydrogen evolution reaction(HER)activity while the Fe-doped ring gives an excellent oxygen evolution reaction(OER)activity,thus forming an in-plane bifunctional electrocatalyst.Finally,as a proof-of-concept for overall water splitting,we constructed a full-cell configuration based on a locally-doped MoS_(2)monolayer,which achieved a cell voltage of 1.87 V at 10 mA·cm^(-2),demonstrating outstanding performance in strong acid electrolytes.Our work provides insight into the hetero-integration of bifunctional electrocatalysts at the atomic level,paving the way for designing transition metal dichalcogenide catalysts with activity-manipulated regions capable of multiple reactions.展开更多
Self-assembled monolayers(SAMs)have been commonly employed as hole-selective layers(HSLs)in inverted(p-i-n)perovskite solar cells(PSCs),and typically only a single-component SAM is applied,which plays limited role in ...Self-assembled monolayers(SAMs)have been commonly employed as hole-selective layers(HSLs)in inverted(p-i-n)perovskite solar cells(PSCs),and typically only a single-component SAM is applied,which plays limited role in selective hole transport.Herein,we synthesize a novel SAM,(4-(3,11-dibro mo-7H-dibenzo[c,g]carbazol-7-yl)butyl)phosphonic acid(Br-4PADBC),and apply it as a complementary component to the commonly used[2-(3,6-dimeth oxy-9H-carbazol-9-yl)ethyl]phosphonic acid(MeO-2PACz)SAM,accomplishing boosted hole transport in inverted PSCs.A series of characterizations and theoretical calculations are employed to unravel the roles of each components within the binary SAM(bi-SAM).The involvements of the non-planar dibenzo[c,g]carbazole unit and electron-withdrawing Br atoms induce larger dipole moment of Br-4PADBC than MeO-2PACz,resulting in much deeper work function of ITO and consequently improved alignment with the valence band energy level of perovskite.Besides,the introduced Br atoms improve the quality of perovskite crystals and help passivate defects of perovskite.On the other hand,the existence of the conventional MeO-2PACz SAM ensures the considerable conductivity of the bi-SAM and thus efficient hole extraction from the perovskite layer.As a result,inverted PSC devices based on bi-SAM HSL deliver a decent power conversion efficiency(PCE)of 24.52%as well as dramatically improved thermal and operational stabilities.展开更多
The pursuit of sustainable energy has driven a significant interest in hydrogen(H_(2))as a clean fuel alternative.A critical challenge is the efficient storage of H_(2),which this study addresses by examining the pote...The pursuit of sustainable energy has driven a significant interest in hydrogen(H_(2))as a clean fuel alternative.A critical challenge is the efficient storage of H_(2),which this study addresses by examining the potential of tricycloquinazoline-based monolayer metal-organic frameworks(MMOFs with the first“M”representing metal species).Using density functional theory,we optimized the structures of MMOFs and calculated H_(2)adsorption energies above the open metal sites,identifying ScMOF,TiMOF,NiMOF,and MgMOF for further validation of their thermodynamic stability via ab-initio molecular dynamics(AIMD)simulations.Force field parameters were fitted via the Morse potential,providing a solid foundation for subsequent grand canonical Monte Carlo simulations.These simulations revealed that the maximum of saturated excess gravimetric H_(2)uptake exceeds 14.16 wt%at 77 K,surpassing other reported MOFs,whether they possess open metal sites or not.At 298 K and 100 bar,both the planar and distorted structures derived from our AIMD simulations demonstrated comparable excess gravimetric H_(2)uptake within the range of 3.05 wt%to 3.94 wt%,once again outperforming other MOFs.Furthermore,lithium(Li)doping significantly enhanced the excess H_(2)uptake,with Li-TiMOF achieving an impressive 6.83 wt%at 298 K and 100 bar,exceeding the ultimate target set by the U.S.Department of Energy.The exceptional H_(2)adsorption capacities of these monolayer MOFs highlight their potential in H_(2)storage,contributing to the design of more efficient hydrogen storage materials and propelling the sustainable hydrogen economy forward.展开更多
Insight into exciton dynamics of two-dimensional(2D)transition metal dichalcogenides(TMDs)is critical for the optimization of their performance in photonic and optoelectronic devices.Although current researches have p...Insight into exciton dynamics of two-dimensional(2D)transition metal dichalcogenides(TMDs)is critical for the optimization of their performance in photonic and optoelectronic devices.Although current researches have primarily concentrated on the near-resonant excitation scenario in 2D TMDs,the case of excitation energies resonating with highenergy excitons or higher energies has yet to be fully elucidated.Here,a comparative analysis is conducted between highenergy excitation(360 nm)and near-resonant excitation(515 nm)utilizing transient absorption spectroscopy to achieve a comprehensive understanding of the exciton dynamics within monolayer WS_(2).It is observed that the high-energy C-exciton can be generated via an up-conversion process under 515 nm excitation,even the energy of which is less than that of the C-exciton.Furthermore,the capacity to efficiently occupy band-edge A-exciton states leads to longer lifetimes for both the C-excitons and the A-excitons under conditions of near-resonant excitation,accompanied by an augmented rate of radiative recombination.This study provides a paradigm for optimizing the performance of 2D TMDs-based devices by offering valuable insights into their exciton dynamics.展开更多
Objective:EPF3 is a fibrinolysin monomer isolated and purified from Pheretima vulgaris Chen,an earthworm used in traditional Chinese medicine as Dilong for treating blood stasis syndrome.Its composition,anticoagulant ...Objective:EPF3 is a fibrinolysin monomer isolated and purified from Pheretima vulgaris Chen,an earthworm used in traditional Chinese medicine as Dilong for treating blood stasis syndrome.Its composition,anticoagulant and fibrinolytic activities,and relevant mechanisms have been confirmed through in vitro experiments.However,whether it has antithrombotic effects in vivo and can be absorbed by the gastrointestinal tract is unknown.This study evaluates the antithrombotic effect in zebrafish and investigates the gastrointestinal stability and intestinal absorption mechanism of this protein in vitro.Methods:The antithrombotic effect of EPF3 in vivo was verified using the zebrafish thrombus model induced by arachidonic acid and FeCl3.Then,the protein bands of EPF3 incubated with simulated gastric fluid(SGF),simulated intestinal fluid(SIF),and homogenate of Caco-2 cells(HC2C)were analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis to evaluate its gastrointestinal stability.Finally,the transport behavior and absorption mechanism of EPF3 were studied using Caco-2 cell monolayer.Results:EPF3 could significantly enhance the returned blood volume and blood flow velocity in zebrafish with platelet aggregation thrombus induced by arachidonic acid.It could also prolong the formation time of tail artery thrombus and increase the blood flow velocity in zebrafish with vessel injury thrombus induced by FeCl3.EPF3 was stable in SIF and HC2C and unstable in SGF.The permeability of EPF3 in Caco-2 monolayer was time-dependent and concentration-dependent.The efflux ratio was less than1.2 during transport,and the transport behavior was not affected by inhibitors.EPF3 could reversibly reduce the expression of tight junction-related proteins,including zonula occludens-1,occludin,and claudin-1 in Caco-2 cells.Conclusion:EPF3 could play a thrombolytic and antithrombotic role in zebrafish.It could be transported and absorbed into the intestine through cellular bypass pathway by opening the intestinal epithelium tight junction.This study provides a scientific explanation for the antithrombotic effect of earthworm and provides a basis for the feasibility of subsequent development of EPF3 as an antithrombotic enteric-soluble preparation.Please cite this article as:Zhong WL,Yang JQ,Liu H,Wu YL,Shen HJ,Li PY,Du SY.Antithrombotic effect in zebrafish of a fibrinolytic protein EPF3 from Dilong(Pheretima vulgaris Chen)and its transport mechanism in Caco-2 monolayer through cell bypass pathway.J Integr Med.2025;23(4):415–428.展开更多
FeSe is an Fe-based paramagnetic superconductor with the simplest structure.The competition between the Néel and stripe magnetic orders is believed to be one of the reasons for the absence of magnetic orders in F...FeSe is an Fe-based paramagnetic superconductor with the simplest structure.The competition between the Néel and stripe magnetic orders is believed to be one of the reasons for the absence of magnetic orders in FeSe.FeSe is recognized as a prototypical platform for competing magnetic interactions,including Néel,stripe,and staggered antiferromagnetic coupling.However,the correlations between these magnetic orders and how they change with varying environmental conditions require further study.Here,we calculated the magnetic order of monolayer FeSe in three diferent environments:pure one,with slight lattice distortion,and on SrTiO_(3) substrate,by frst principles calculations.We fnd that in the calculated dispersion relation E(q)between the spin spiral energy E and spin spiral vector q of the monolayer FeSe structure,the stripe magnetic order M(π/2,π/2)has the lowest energy,and there is a fat E(q)between the wave vector X(π/2,0)and Néel magnetic order 2X(π,0),which are the degenerate E(q)states.The ground state of M and the highest density of states around 2X may be the reason for the competition of two magnetic orders.The slight lattice distortion does not alter the magnetic properties of monolayer FeSe.When monolayer FeSe is attached to the SrTiO_(3)substrate,the degenerate E(q)is still retained;meanwhile,the energy of the 2X(π,0)state is closer to the M state,which may be one of the reasons for the increase of superconducting temperature in FeSe/SrTiO_(3).展开更多
The dual quantum spin Hall insulator(QSHI)is a newly discovered topological state in the two-dimensional(2D)material TaIrTe_(4),which exhibits both a traditional Z_(2)band gap at the charge neutrality point and a Van ...The dual quantum spin Hall insulator(QSHI)is a newly discovered topological state in the two-dimensional(2D)material TaIrTe_(4),which exhibits both a traditional Z_(2)band gap at the charge neutrality point and a Van Hove singularity(VHS)that induces a correlated Z_(2)band gap with weak doping.Inspired by the recent progress in theoretical understanding and experimental measurements,a promising dual QSHI is predicted in the counterpart material of the NbIrTe_(4)monolayer by first-principles calculations.In addition to the well-known band inversion at the charge neutrality point,two new band inversions are found after a charge density wave(CDW)phase transition when the chemical potential is near the VHS:one direct and one indirect Z_(2)band gap.The VHSinduced non-trivial band gap is approximately 10 meV,significantly larger than that of TaIrTe_(4).Furthermore,as the newly generated band gap is mainly dominated by the 4d orbitals of Nb,the electronic correlation effects should be stronger for NbIrTe_(4)than for TaIrTe_(4).Therefore,the dual QSHI state in the NbIrTe_(4)monolayer is expected to provide a strong platform for investigating the interplay between topologies and correlation effects.展开更多
The labels of VU1 and VU2 in Fig.1(b)of the paper[Chin.Phys.B 34046801(2025)]were not correctly placed.The correct figure is provided.This modification does not affect the result presented in the paper.
We report the discovery of bistable polar states with switchable polarization in the Janus monolayer 1T-MoSSe,induced by symmetry breaking in its chalcogen atomic layers.Our results demonstrate that Janus 1T-MoSSe exh...We report the discovery of bistable polar states with switchable polarization in the Janus monolayer 1T-MoSSe,induced by symmetry breaking in its chalcogen atomic layers.Our results demonstrate that Janus 1T-MoSSe exhibits two out-of-plane bistable polar states with switchable polarization,rather than polarization emerging from a non-polar phase,which represents an unconventional form of ferroelectric-like behavior.First-principles calculations and phenomenological modeling reveal that the inequivalent stacking of sulfur and selenium(S/Se)atoms breaks central inversion symmetry,activating non-degenerate phonon modes at the K-point(K_(2)/K_(3))that drive the structural transformation between metastable d1TS and d1TSe phases.This coupling enables bipolar control of out-of-plane polarization through atomic displacements and charge redistribution,resulting in a polarization change ofΔP≈±0.3μC/cm^(2).The Landau free energy analysis indicates that anharmonic terms and inter-mode coupling generate an asymmetric double-well potential,which is essential for the stabilization of bistable polar states.Molecular dynamics simulations show that the d1TS phase remains stable at high temperatures,whereas the d1TSe phase undergoes an irreversible phase transition near 300 K,accompanied by a Peierls-like distortion of the Mo atomic chain.This transition is driven by differences in electronegativity,atomic radius,and d-p orbital hybridization between S and Se.Our findings establish a theoretical framework for engineering nonlinear responses in two-dimensional(2D)ferroelectrics and suggest that low-energy polarization reversal at room temperature can be achieved through strain or electric-field control,offering promising opportunities for non-volatile memory and piezoelectric sensing applications.展开更多
Inverted p-i-n perovskite solar cells(PSCs)based on self-assembled monolayers(SAMs)as hole-selective layers(HSLs)have produced potential record efficiencies of more than 26%by tuning work function,dipole,and passivati...Inverted p-i-n perovskite solar cells(PSCs)based on self-assembled monolayers(SAMs)as hole-selective layers(HSLs)have produced potential record efficiencies of more than 26%by tuning work function,dipole,and passivation defects.However,the stability of the SAM molecules,the stability of the molecular anchoring conformation,and the impact on the stability of subsequent PSCs have not been clearly elucidated.In this review,we systematically discussed the intrinsic connection between the molecular conformation(including anchoring groups,spacer groups,and terminal groups)and the stability of SAMs.Sequentially,the research progress of SAMs as HSLs in improving the stability of PSCs is summarized,including photostability,thermal stability,ion migration,and residual stress.Finally,we look forward to the shortcomings and possible challenges of using SAMs as HSLs for inverted PSCs.展开更多
Kagome materials are known for hosting exotic quantum states,including quantum spin liquids,charge density waves,and unconventional superconductivity.The search for kagome monolayers is driven by their ability to exhi...Kagome materials are known for hosting exotic quantum states,including quantum spin liquids,charge density waves,and unconventional superconductivity.The search for kagome monolayers is driven by their ability to exhibit neat and well-defined kagome bands near the Fermi level,which are more easily realized in the absence of interlayer interactions.However,this absence also destabilizes the monolayer forms of many bulk kagome materials,posing significant challenges to their discovery.In this work,we propose a strategy to address this challenge by utilizing oxygen vacancies in transition metal oxides within a“1+3”design framework.Through high-throughput computational screening of 349 candidate materials,we identified 12 thermodynamically stable kagome monolayers with diverse electronic and magnetic properties.These materials were classified into three categories based on their lattice geometry,symmetry,band gaps,and magnetic configurations.Detailed analysis of three representative monolayers revealed kagome band features near their Fermi levels,with orbital contributions varying between oxygen 2p and transition metal d states.This study demonstrates the feasibility of the“1+3”strategy,offering a promising approach to uncovering low-dimensional kagome materials and advancing the exploration of their quantum phenomena.展开更多
Directly correlating the morphology and composition of interfacial water is vital not only for studying water icing under critical conditions but also for understanding the role of protein–water interac-tions in bio-...Directly correlating the morphology and composition of interfacial water is vital not only for studying water icing under critical conditions but also for understanding the role of protein–water interac-tions in bio-relevant systems.In this study,we present a model system to study two-dimensional(2D)water layers under ambient conditions by using self-assembled monolayers(SAMs)supporting the physisorp-tion of the Cytochrome C(Cyt C)protein layer.We observed that the 2D island-like water layers were uniformly distributed on the SAMs as characterized by atomic force microscopy,and their composition was confirmed by nano-atomic force microscopy-infrared spectroscopy and Raman spectroscopy.In addition,these 2D flakes could grow under high-humidity conditions or melt upon the introduction of a heat source.The formation of these flakes is attributed to the activation energy for water desorption from the Cyt C being nearly twofold high than that from the SAMs.Our results provide a new and effective method for further understanding the water–protein interactions.展开更多
基金supported by the National Key R&D Program of China(Grant No.2022YFB3505301)the National Key R&D Program of Shanxi Province(Grant No.202302050201014)+1 种基金the National Natural Science Foundation of China(Grant No.12304148)the Natural Science Basic Research Program of Shanxi Province(Grant No.202203021222219)。
文摘Multiferroic tunnel junctions(MFTJs),which combine tunneling magnetoresistance(TMR)and electroresistance(TER)efects,have emerged as key candidates for data storage.Two-dimensional van der Waals(vdW)MFTJs,in particular,are promising spintronic devices for the post-Moore era.However,these vdW MFTJs are typically based on multiferroics composed of ferromagnetic and ferroelectric materials or multilayer magnetic materials with sliding ferroelectricity,which increases device fabrication complexity.In this work,we design a vdW MFTJ using bilayer MoPtGe_(2)S_(6),a material with homologous multiferroicity in each monolayer,combined with symmetric PtTe_(2)electrodes.Using frst-principles calculations based on density functional theory and nonequilibrium Green's functions,we theoretically explore the spin-polarized electronic transport properties of this MFTJ.By controlling the ferroelectric and ferromagnetic polarization directions of bilayer MoPtGe_(2)S_(6),the MFTJ can exhibit six distinct non-volatile resistance states,with maximum TMR(137%)and TER(1943%)ratios.Under biaxial strain,TMR and TER can increase to 265%and 4210%,respectively.The TER ratio also increases to 2186%under a 0.1 V bias voltage.Remarkably,the MFTJ exhibits a pronounced spin-fltering and a signifcant negative diferential resistance efect.These fndings not only highlight the potential of monolayer multiferroic MoPtGe_(2)S_(6)for MFTJs but also ofer valuable theoretical insights for future experimental investigations.
基金supported by the National Natural Science Foundation of China(Grant Nos.12022508,12074394,and 22125604)Shanghai Supercomputer Center of ChinaShanghai Snowlake Technology Co.Ltd.
文摘The stable nanobubbles adhered to mineral surfaces may facilitate their efficient separation via flotation in the mining industry.However,the state of nanobubbles on mineral solid surfaces is still elusive.In this study,molecular dynamics(MD)simulations are employed to examine mineral-like model surfaces with varying degrees of hydrophobicity,modulated by surface charges,to elucidate the adsorption behavior of nanobubbles at the interface.Our findings not only contribute to the fundamental understanding of nanobubbles but also have potential applications in the mining industry.We observed that as the surface charge increases,the contact angle of the nanobubbles increases accordingly with shape transformation from a pancake-like gas film to a cap-like shape,and ultimately forming a stable nanobubble upon an ordered water monolayer.When the solid–water interactions are weak with a small partial charge,the hydrophobic gas(N_(2))molecules accumulate near the solid surfaces.However,we have found,for the first time,that gas molecules assemble a nanobubble on the water monolayer adjacent to the solid surfaces with large partial charges.Such phenomena are attributed to the formation of a hydrophobic water monolayer with a hydrogen bond network structure near the surface.
基金financial support from the National Natural Science Foundation of China(Grant No.61971201)。
文摘High-resolution transmission electron microscopy(HRTEM)promises rapid atomic-scale dynamic structure imaging.Yet,the precision limitations of aberration parameters and the challenge of eliminating aberrations in Cs-corrected transmission electron microscopy constrain resolution.A machine learning algorithm is developed to determine the aberration parameters with higher precision from small,lattice-periodic crystal images.The proposed algorithm is then validated with simulated HRTEM images of graphene and applied to the experimental images of a molybdenum disulfide(MoS_(2))monolayer with 25 variables(14 aberrations)resolved in wide ranges.Using these measured parameters,the phases of the exit-wave functions are reconstructed for each image in a focal series of MoS_(2)monolayers.The images were acquired due to the unexpected movement of the specimen holder.Four-dimensional data extraction reveals time-varying atomic structures and ripple.In particular,the atomic evolution of the sulfur-vacancy point and line defects,as well as the edge structure near the amorphous,is visualized as the resolution has been improved from about 1.75?to 0.9 A.This method can help salvage important transmission electron microscope images and is beneficial for the images obtained from electron microscopes with average stability.
基金supports by the Grant-in-Aid of Scientific Research of Challenging Research(Exploratory)(JP23K17738)to TS from MEXT of Japanthe 41st grant of research from Nippon Sheet Glass Foundation for Materials Science and Engineering to TS.
文摘A redox-active monolayer on an optically transparent electrode constitutes a typical platform for spectroelectrochemical sensing.The necessity for its sophistication arises from the availability of multi-dimensional sensing signals.Simultaneous monitoring of the redox current and color change synchronized with the oxidation state change significantly enhances sen-sitivity and selectivity.This study aimed to elucidate the modification of an indium tin oxide(ITO)electrode with a viologen monolayer with an ordered orientation.Novel methods were developed to immobilize a viologen molecule bearing a car-boxyl group to form assembled monolayers through a condensation reaction using 1-ethyl-3-(3-dimethylaminopropyl)-car-bodiimide with N-hydroxy-succinimide(EDC/NHS).In the two methods of immobilization,one utilizes a two-step process to firstly form an aromatic siloxane base layer and subsequently attach the viologen derivative through an amide linkage by post-amidation.The other employs a direct ester linkage between the hydroxyl groups of the ITO surface and the car-boxyl group of the viologen derivative.The latter method was also applied to immobilize a ferrocenyl group at a very short distance from the ITO surface.Potential-modulated UV-visible transmission absorption spectral measurement techniques with oblique incidence of plane-polarized light were employed to determine the orientation of the longitudinal axis of the reduced form of the viologen.The frequency dependence data of the potential-modulated transmission absorption signals were utilized to analyze the electron transfer kinetics.The performance of the two viologen-modified electrodes was com-pared to that of an ITO modified by post-amidation to the most commonly used base layer prepared with 3-aminopropyl triethoxysilane.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFA1610000)the National Natural Science Foundation of China(Grant Nos.12304036 and 12304265)+1 种基金the Basic and Applied Basic Research Foundation of Guangdong Province,China(Grant No.2023A1515010071)the Fundamental Research Funds for the Central Universities to Sun Yat-sen University(Grant No.23xkjc016).
文摘Monolayer CrI_(3),crystalizing in the P31m space group,is a prototypical two-dimensional(2D)material for observing intrinsic ferromagnetic order.However,its relatively low Curie temperature(T_(C))of 45 K severely limits its practical applications,highlighting the need to explore novel metastable polymorphs with enhanced magnetic properties.In this study,we employ a global crystal structure search technique combined with first-principles calculations to systematically investigate new monolayer CrI_(3)phases.Our structural predictions identify two novel polymorphs with Cm and P2/m space groups,both of which are dynamically stable and exhibit significantly higher T_(C)values of 145 K and 81 K,respectively.Electronic property calculations show that the Cm phase is a half-metal,while the P2/m phase is semiconducting with a bandgap of 0.14 eV.Monte Carlo simulations attribute these enhanced T_(C)values to a notable increase in exchange interactions.These findings expand the known phase space of CrI_(3)and provide a promising pathway for designing hightemperature 2D ferromagnets for next-generation spintronic applications.
基金supported by funding from the Energy Materials and Surface Sciences Unit of the Okinawa Institute of Science and Technology Graduate University,the OIST R&D Cluster Research Program,the OIST Proof of Concept(POC)Program,the JSPS KAKENHI Grant Number JP21F21754 and Alexander von Humboldt Foundation。
文摘Self-assembled monolayers(SAMs)are widely used as hole transport materials in inverted perovskite solar cells,offering low parasitic absorption and suitability for semitransparent and tandem solar cells.While SAMs have shown to be promising in small-area devices(≤1 cm^(2)),their application in larger areas has been limited by a lack of knowledge regarding alternative deposition methods beyond the common spin-coating approach.Here,we compare spin-coating and upscalable methods such as thermal evaporation and spray-coating for[2-(9H-carbazol-9-yl)ethyl]phosphonic acid(2PACz),one of the most common carbazole-based SAMs.The impact of these deposition methods on the device performance is investigated,revealing that the spray-coating technique yields higher device performance.Furthermore,our work provides guidelines for the deposition of SAM materials for the fabrication of perovskite solar modules.In addition,we provide an extensive characterization of 2PACz films focusing on thermal evaporation and spray-coating methods,which allow for thicker 2PACz deposition.It is found that the optimal 2PACz deposition conditions corresponding to the highest device performances do not always correlate with the monolayer characteristics.
基金supported by the National Key R&D Program of China under Grant No.2021YFA1400500the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No.XDB33000000+1 种基金the National Natural Science Foundation of China under Grant No.12334003the Beijing Municipal Natural Science Foundation under Grant Nos.JQ22001 and QY23014。
文摘Establishing the structure-property relationship in amorphous materials has been a long-term grand challenge due to the lack of a unified description of the degree of disorder.In this work,we develop SPRamNet,a neural network based machine-learning pipeline that effectively predicts structure-property relationship of amorphous material via global descriptors.Applying SPRamNet on the recently discovered amorphous monolayer carbon,we successfully predict the thermal and electronic properties.More importantly,we reveal that a short range of pair correlation function can readily encode sufficiently rich information of the structure of amorphous material.Utilizing powerful machine learning architectures,the encoded information can be decoded to reconstruct macroscopic properties involving many-body and long-range interactions.Establishing this hidden relationship offers a unified description of the degree of disorder and eliminates the heavy burden of measuring atomic structure,opening a new avenue in studying amorphous materials.
基金supported by the National Natural Science Foundation of China (Grant No. 12174382)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos. XDB0460000 and XDB28000000)the Innovation Program for Quantum Science and Technology (Grant Nos. 2024ZD0300104 and 2021ZD0302600)。
文摘The competition between dimensionality and ordering in multiferroic materials is of great interest for both fundamental physics and potential applications. Combining first-principles calculations with micromagnetic simulations, we investigate recently synthesized ultrathin perovskite bismuth ferrite(BFO) films. Our numerical results reveal that, at the monolayer limit, the ferroelectricity of BFO is missing because the octahedral distortions are constrained. However, the monolayer bismuth ferrite is a topological antiferromagnetic metal with tunable bimeron magnetic structure. The dual topologically non-trivial characteristics make monolayer bismuth ferrite a multifunctional building block in future spintronic devices.
基金supported by the National Natural Science Foundation of China(Nos.22175060 and 22376062)JSPS Grant-in-Aid for Scientific Research(Nos.JP21H05235,JP22H05478 and JP22F22358)+1 种基金China Postdoctoral Science Foundation(No.2022M722867)the Key Research Project of Higher Education Institutions in Henan Province(No.23A530001).
文摘Exploring earth-abundant,highly active bifunctional electrocatalysts for efficient hydrogen and oxygen evolution is crucial for water splitting.However,due to their distinct free energies and conducting behaviors(electron/hole),balancing the catalytic efficiency between hydrogen and oxygen evolution remains challenging for achieving bifunctional electrocatalysts.Here,we report a locally-doped MoS_(2)monolayer with an in-plane heterostructure acting as a bifunctional electrocatalyst and apply it to the overall water splitting.In this heterostructure,the core region contains Mo/S vacancies,while the ring region was doped by Fe atoms(in two substitution configurations:1FeMo and 3FeMo-VS clusters)with a p-type conductive characteristic.Our micro-cell measurements,combined with density functional theory(DFT)calculations,reveal that the vacancies-rich core region presents remarkable hydrogen evolution reaction(HER)activity while the Fe-doped ring gives an excellent oxygen evolution reaction(OER)activity,thus forming an in-plane bifunctional electrocatalyst.Finally,as a proof-of-concept for overall water splitting,we constructed a full-cell configuration based on a locally-doped MoS_(2)monolayer,which achieved a cell voltage of 1.87 V at 10 mA·cm^(-2),demonstrating outstanding performance in strong acid electrolytes.Our work provides insight into the hetero-integration of bifunctional electrocatalysts at the atomic level,paving the way for designing transition metal dichalcogenide catalysts with activity-manipulated regions capable of multiple reactions.
基金the National Natural Science Foundation of China(51925206,U1932214,52302052)the National Natural Science Foundation of China(52322318)+6 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0450301)the Fundamental Research Funds for the Central Universities(WK2060000051,20720220009)the National Key Research and Development Program of China(No.2023YFB3809700)the Innovation and Technology Fund(GHP/100/20SZ,GHP/102/20GD,MRP/040/21X,ITS/147/22FP)the Research Grants Council of Hong Kong Grant(N_City U102/23,C4005-22Y,C1055-23G,11306521)the Green Tech Fund(GTF202020164)the Science Technology and Innovation Committee of Shenzhen Municipality(SGDX20210823104002015,JCYJ20220818101018038)。
文摘Self-assembled monolayers(SAMs)have been commonly employed as hole-selective layers(HSLs)in inverted(p-i-n)perovskite solar cells(PSCs),and typically only a single-component SAM is applied,which plays limited role in selective hole transport.Herein,we synthesize a novel SAM,(4-(3,11-dibro mo-7H-dibenzo[c,g]carbazol-7-yl)butyl)phosphonic acid(Br-4PADBC),and apply it as a complementary component to the commonly used[2-(3,6-dimeth oxy-9H-carbazol-9-yl)ethyl]phosphonic acid(MeO-2PACz)SAM,accomplishing boosted hole transport in inverted PSCs.A series of characterizations and theoretical calculations are employed to unravel the roles of each components within the binary SAM(bi-SAM).The involvements of the non-planar dibenzo[c,g]carbazole unit and electron-withdrawing Br atoms induce larger dipole moment of Br-4PADBC than MeO-2PACz,resulting in much deeper work function of ITO and consequently improved alignment with the valence band energy level of perovskite.Besides,the introduced Br atoms improve the quality of perovskite crystals and help passivate defects of perovskite.On the other hand,the existence of the conventional MeO-2PACz SAM ensures the considerable conductivity of the bi-SAM and thus efficient hole extraction from the perovskite layer.As a result,inverted PSC devices based on bi-SAM HSL deliver a decent power conversion efficiency(PCE)of 24.52%as well as dramatically improved thermal and operational stabilities.
基金supported by National Natural Science Foundation of China(Grant No.12104237)Scientific Research Foundation of Nanjing University of Posts and Telecommunications(No.NY219031).
文摘The pursuit of sustainable energy has driven a significant interest in hydrogen(H_(2))as a clean fuel alternative.A critical challenge is the efficient storage of H_(2),which this study addresses by examining the potential of tricycloquinazoline-based monolayer metal-organic frameworks(MMOFs with the first“M”representing metal species).Using density functional theory,we optimized the structures of MMOFs and calculated H_(2)adsorption energies above the open metal sites,identifying ScMOF,TiMOF,NiMOF,and MgMOF for further validation of their thermodynamic stability via ab-initio molecular dynamics(AIMD)simulations.Force field parameters were fitted via the Morse potential,providing a solid foundation for subsequent grand canonical Monte Carlo simulations.These simulations revealed that the maximum of saturated excess gravimetric H_(2)uptake exceeds 14.16 wt%at 77 K,surpassing other reported MOFs,whether they possess open metal sites or not.At 298 K and 100 bar,both the planar and distorted structures derived from our AIMD simulations demonstrated comparable excess gravimetric H_(2)uptake within the range of 3.05 wt%to 3.94 wt%,once again outperforming other MOFs.Furthermore,lithium(Li)doping significantly enhanced the excess H_(2)uptake,with Li-TiMOF achieving an impressive 6.83 wt%at 298 K and 100 bar,exceeding the ultimate target set by the U.S.Department of Energy.The exceptional H_(2)adsorption capacities of these monolayer MOFs highlight their potential in H_(2)storage,contributing to the design of more efficient hydrogen storage materials and propelling the sustainable hydrogen economy forward.
基金supported by the National Natural Science Foundation of China(Grant Nos.12474421 and 12104066)the Fund from Education Department of Jilin Province(Grant Nos.JJKH20250473KJ and JJKH20241413KJ)the Fund from Department of Science and Technology of Jilin Province(Grant No.YDZJ202101ZYTS041)。
文摘Insight into exciton dynamics of two-dimensional(2D)transition metal dichalcogenides(TMDs)is critical for the optimization of their performance in photonic and optoelectronic devices.Although current researches have primarily concentrated on the near-resonant excitation scenario in 2D TMDs,the case of excitation energies resonating with highenergy excitons or higher energies has yet to be fully elucidated.Here,a comparative analysis is conducted between highenergy excitation(360 nm)and near-resonant excitation(515 nm)utilizing transient absorption spectroscopy to achieve a comprehensive understanding of the exciton dynamics within monolayer WS_(2).It is observed that the high-energy C-exciton can be generated via an up-conversion process under 515 nm excitation,even the energy of which is less than that of the C-exciton.Furthermore,the capacity to efficiently occupy band-edge A-exciton states leads to longer lifetimes for both the C-excitons and the A-excitons under conditions of near-resonant excitation,accompanied by an augmented rate of radiative recombination.This study provides a paradigm for optimizing the performance of 2D TMDs-based devices by offering valuable insights into their exciton dynamics.
基金supported by grants from the Fundamental Research Funds for the Central Universities(No.2020-JYB-ZDGG-032)National Natural Science Foundation of China(No.82104352)。
文摘Objective:EPF3 is a fibrinolysin monomer isolated and purified from Pheretima vulgaris Chen,an earthworm used in traditional Chinese medicine as Dilong for treating blood stasis syndrome.Its composition,anticoagulant and fibrinolytic activities,and relevant mechanisms have been confirmed through in vitro experiments.However,whether it has antithrombotic effects in vivo and can be absorbed by the gastrointestinal tract is unknown.This study evaluates the antithrombotic effect in zebrafish and investigates the gastrointestinal stability and intestinal absorption mechanism of this protein in vitro.Methods:The antithrombotic effect of EPF3 in vivo was verified using the zebrafish thrombus model induced by arachidonic acid and FeCl3.Then,the protein bands of EPF3 incubated with simulated gastric fluid(SGF),simulated intestinal fluid(SIF),and homogenate of Caco-2 cells(HC2C)were analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis to evaluate its gastrointestinal stability.Finally,the transport behavior and absorption mechanism of EPF3 were studied using Caco-2 cell monolayer.Results:EPF3 could significantly enhance the returned blood volume and blood flow velocity in zebrafish with platelet aggregation thrombus induced by arachidonic acid.It could also prolong the formation time of tail artery thrombus and increase the blood flow velocity in zebrafish with vessel injury thrombus induced by FeCl3.EPF3 was stable in SIF and HC2C and unstable in SGF.The permeability of EPF3 in Caco-2 monolayer was time-dependent and concentration-dependent.The efflux ratio was less than1.2 during transport,and the transport behavior was not affected by inhibitors.EPF3 could reversibly reduce the expression of tight junction-related proteins,including zonula occludens-1,occludin,and claudin-1 in Caco-2 cells.Conclusion:EPF3 could play a thrombolytic and antithrombotic role in zebrafish.It could be transported and absorbed into the intestine through cellular bypass pathway by opening the intestinal epithelium tight junction.This study provides a scientific explanation for the antithrombotic effect of earthworm and provides a basis for the feasibility of subsequent development of EPF3 as an antithrombotic enteric-soluble preparation.Please cite this article as:Zhong WL,Yang JQ,Liu H,Wu YL,Shen HJ,Li PY,Du SY.Antithrombotic effect in zebrafish of a fibrinolytic protein EPF3 from Dilong(Pheretima vulgaris Chen)and its transport mechanism in Caco-2 monolayer through cell bypass pathway.J Integr Med.2025;23(4):415–428.
基金supported by the National Natural Science Foundation of China(Grant Nos.11204131 and 11974181)。
文摘FeSe is an Fe-based paramagnetic superconductor with the simplest structure.The competition between the Néel and stripe magnetic orders is believed to be one of the reasons for the absence of magnetic orders in FeSe.FeSe is recognized as a prototypical platform for competing magnetic interactions,including Néel,stripe,and staggered antiferromagnetic coupling.However,the correlations between these magnetic orders and how they change with varying environmental conditions require further study.Here,we calculated the magnetic order of monolayer FeSe in three diferent environments:pure one,with slight lattice distortion,and on SrTiO_(3) substrate,by frst principles calculations.We fnd that in the calculated dispersion relation E(q)between the spin spiral energy E and spin spiral vector q of the monolayer FeSe structure,the stripe magnetic order M(π/2,π/2)has the lowest energy,and there is a fat E(q)between the wave vector X(π/2,0)and Néel magnetic order 2X(π,0),which are the degenerate E(q)states.The ground state of M and the highest density of states around 2X may be the reason for the competition of two magnetic orders.The slight lattice distortion does not alter the magnetic properties of monolayer FeSe.When monolayer FeSe is attached to the SrTiO_(3)substrate,the degenerate E(q)is still retained;meanwhile,the energy of the 2X(π,0)state is closer to the M state,which may be one of the reasons for the increase of superconducting temperature in FeSe/SrTiO_(3).
基金supported by the National Key R&D Program of China(Grant No.2021YFB3501503)the National Natural Science Foundation of China(Grant Nos.52271016 and 52188101)the Foundation of Liaoning Province(Grant No.XLYC2203080)。
文摘The dual quantum spin Hall insulator(QSHI)is a newly discovered topological state in the two-dimensional(2D)material TaIrTe_(4),which exhibits both a traditional Z_(2)band gap at the charge neutrality point and a Van Hove singularity(VHS)that induces a correlated Z_(2)band gap with weak doping.Inspired by the recent progress in theoretical understanding and experimental measurements,a promising dual QSHI is predicted in the counterpart material of the NbIrTe_(4)monolayer by first-principles calculations.In addition to the well-known band inversion at the charge neutrality point,two new band inversions are found after a charge density wave(CDW)phase transition when the chemical potential is near the VHS:one direct and one indirect Z_(2)band gap.The VHSinduced non-trivial band gap is approximately 10 meV,significantly larger than that of TaIrTe_(4).Furthermore,as the newly generated band gap is mainly dominated by the 4d orbitals of Nb,the electronic correlation effects should be stronger for NbIrTe_(4)than for TaIrTe_(4).Therefore,the dual QSHI state in the NbIrTe_(4)monolayer is expected to provide a strong platform for investigating the interplay between topologies and correlation effects.
文摘The labels of VU1 and VU2 in Fig.1(b)of the paper[Chin.Phys.B 34046801(2025)]were not correctly placed.The correct figure is provided.This modification does not affect the result presented in the paper.
基金support from the National Natural Science Foundation of China(Grant Nos.12334014 and 11727902)the Overseas High-level Talents Program of the Chinese Academy of Sciences.
文摘We report the discovery of bistable polar states with switchable polarization in the Janus monolayer 1T-MoSSe,induced by symmetry breaking in its chalcogen atomic layers.Our results demonstrate that Janus 1T-MoSSe exhibits two out-of-plane bistable polar states with switchable polarization,rather than polarization emerging from a non-polar phase,which represents an unconventional form of ferroelectric-like behavior.First-principles calculations and phenomenological modeling reveal that the inequivalent stacking of sulfur and selenium(S/Se)atoms breaks central inversion symmetry,activating non-degenerate phonon modes at the K-point(K_(2)/K_(3))that drive the structural transformation between metastable d1TS and d1TSe phases.This coupling enables bipolar control of out-of-plane polarization through atomic displacements and charge redistribution,resulting in a polarization change ofΔP≈±0.3μC/cm^(2).The Landau free energy analysis indicates that anharmonic terms and inter-mode coupling generate an asymmetric double-well potential,which is essential for the stabilization of bistable polar states.Molecular dynamics simulations show that the d1TS phase remains stable at high temperatures,whereas the d1TSe phase undergoes an irreversible phase transition near 300 K,accompanied by a Peierls-like distortion of the Mo atomic chain.This transition is driven by differences in electronegativity,atomic radius,and d-p orbital hybridization between S and Se.Our findings establish a theoretical framework for engineering nonlinear responses in two-dimensional(2D)ferroelectrics and suggest that low-energy polarization reversal at room temperature can be achieved through strain or electric-field control,offering promising opportunities for non-volatile memory and piezoelectric sensing applications.
基金supported by the Natural Science Foundation of China(22425903,U24A20568,61705102,62288102,22409091,22409090 and 62205142)the National Key R&D Program of China(2023YFB4204500)the Jiangsu Provincial Departments of Science and Technology(BE2022023,BK20220010,BZ2023060,BK20240561,and BK20240562)。
文摘Inverted p-i-n perovskite solar cells(PSCs)based on self-assembled monolayers(SAMs)as hole-selective layers(HSLs)have produced potential record efficiencies of more than 26%by tuning work function,dipole,and passivation defects.However,the stability of the SAM molecules,the stability of the molecular anchoring conformation,and the impact on the stability of subsequent PSCs have not been clearly elucidated.In this review,we systematically discussed the intrinsic connection between the molecular conformation(including anchoring groups,spacer groups,and terminal groups)and the stability of SAMs.Sequentially,the research progress of SAMs as HSLs in improving the stability of PSCs is summarized,including photostability,thermal stability,ion migration,and residual stress.Finally,we look forward to the shortcomings and possible challenges of using SAMs as HSLs for inverted PSCs.
基金financial support from the National Key Research&Development Program of China(Grant No.2023YFA1406500)the National Natural Science Foundation of China(Grant Nos.12104504,52461160327 and 92477205)the Fundamental Research Funds for the Central Universities,and the Research Funds of Renmin University of China[Grant Nos.22XNKJ30(W.J.)and 24XNKJ17(C.W.)]。
文摘Kagome materials are known for hosting exotic quantum states,including quantum spin liquids,charge density waves,and unconventional superconductivity.The search for kagome monolayers is driven by their ability to exhibit neat and well-defined kagome bands near the Fermi level,which are more easily realized in the absence of interlayer interactions.However,this absence also destabilizes the monolayer forms of many bulk kagome materials,posing significant challenges to their discovery.In this work,we propose a strategy to address this challenge by utilizing oxygen vacancies in transition metal oxides within a“1+3”design framework.Through high-throughput computational screening of 349 candidate materials,we identified 12 thermodynamically stable kagome monolayers with diverse electronic and magnetic properties.These materials were classified into three categories based on their lattice geometry,symmetry,band gaps,and magnetic configurations.Detailed analysis of three representative monolayers revealed kagome band features near their Fermi levels,with orbital contributions varying between oxygen 2p and transition metal d states.This study demonstrates the feasibility of the“1+3”strategy,offering a promising approach to uncovering low-dimensional kagome materials and advancing the exploration of their quantum phenomena.
基金supported by the National Natural Science Foundation of China(22273045,52488101 and 22472043)Ningbo Youth Science and Technology Innovation Leading Talent(2023QL041)Tsinghua University Independent Scientific Research Plan for Young Investigator,Tsinghua University Dushi Program,and Initiative Scientific Research Program。
文摘Directly correlating the morphology and composition of interfacial water is vital not only for studying water icing under critical conditions but also for understanding the role of protein–water interac-tions in bio-relevant systems.In this study,we present a model system to study two-dimensional(2D)water layers under ambient conditions by using self-assembled monolayers(SAMs)supporting the physisorp-tion of the Cytochrome C(Cyt C)protein layer.We observed that the 2D island-like water layers were uniformly distributed on the SAMs as characterized by atomic force microscopy,and their composition was confirmed by nano-atomic force microscopy-infrared spectroscopy and Raman spectroscopy.In addition,these 2D flakes could grow under high-humidity conditions or melt upon the introduction of a heat source.The formation of these flakes is attributed to the activation energy for water desorption from the Cyt C being nearly twofold high than that from the SAMs.Our results provide a new and effective method for further understanding the water–protein interactions.
