Properties of ferroelectric xBiInO3-（1-x）PbTiO3（xBI-（1-x）PT） thin films deposited on（101） SrRuO3/（200）Pt/（200） MgO substrates by rf magnetron sputtering method and effects of deposition conditions are inve...Properties of ferroelectric xBiInO3-（1-x）PbTiO3（xBI-（1-x）PT） thin films deposited on（101） SrRuO3/（200）Pt/（200） MgO substrates by rf magnetron sputtering method and effects of deposition conditions are investigated.The structures of the xBI-（1-x）PT films are characterized by x-ray diffraction and scanning electron microscopy.The results indicate that the thin films are grown with mainly（001） orientation. The chemical compositions of the films are analyzed by scanning electron probe and the results indicate that the loss phenomena of Pb and Bi elements depend on the pressure and temperature during the sputtering process.The sputtering parameters including target composition, substrate temperature, and gas pressure are adjusted to obtain optimum sputtering conditions. To decrease leakage currents,2 mol% La2 O3 is doped in the targets. The P-E hysteresis loops show that the optimized xBI-（1-x）PT（x = 0.24） film has high ferroelectricities with remnant polarization2 Pr = 80μC/cm2 and coercive electric field 2 EC = 300 kV/cm. The Curie temperature is about 640℃. The results show that the films have optimum performance and will have wide applications.展开更多
Interfacial ferroelectricity is a recently established mechanism for generating spontaneous reversible electric polarization,arising from the charge transfer between stacked van der Waals layered atomic crystals.It ha...Interfacial ferroelectricity is a recently established mechanism for generating spontaneous reversible electric polarization,arising from the charge transfer between stacked van der Waals layered atomic crystals.It has been realized in both naturally formed multilayer crystals and moirésuperlattices.Owing to the large number of material choices and combinations,this approach is highly versatile,greatly expanding the scope of ultrathin ferroelectrics.A key advantage of interfacial ferroelectricity is its potential to couple with preexisting properties of the constituent layers,enabling their electrical manipulation through ferroelectric switching and paving the way for advanced device functionalities.This review article summarizes recent experimental progress in interfacial ferroelectricity,with an emphasis on its coupling with a variety of electronic properties.After introducing the underlying mechanism of interfacial ferroelectricity and the range of material systems discovered to date,we highlight selected examples showcasing ferroelectric control of excitonic optical properties,Berry curvature effects,and superconductivity.We also discuss the challenges and opportunities that await further studies in this field.展开更多
Van der Waals(vdW)ferroelectric-semiconductor heterojunction provides reconfigurable band alignment based on optical/electrical-assisted polarization switching,which shows great potential to construct artificial visua...Van der Waals(vdW)ferroelectric-semiconductor heterojunction provides reconfigurable band alignment based on optical/electrical-assisted polarization switching,which shows great potential to construct artificial visual neural systems.However,the mechanical exfoliation fabrication scheme for proof-of-concept demonstrations and fundamental studies is cumbersome and not scalable for practical application.Here,we present a synthetic strategy for the large-scale and high crystallinity growth of planar/verticalα-In_(2)Se_(3)/MoS_(2)heterojunctions by dynamically tuning the growth temperature.Furthermore,based on theα-In_(2)Se_(3)/MoS_(2)heterostructures,photo-synapse devices are designed and fabricated to simulate visual neural systems functions,including multistate storage,optical logic operation,potentiation and depression,paired-pulse facilitation(PPF),short-term memory(STM),long-term memory(LTM),and Learning-Forgetting-Relearning.By coupling the spatiotemporally relevant optical and electric information,the device can mimic the superior biological visual system’s light adaptation and Pavlovian conditioning.This work provides a strategy for dynamically tuning the orientation of ferroelectric-semiconductor heterojunction stacks and will give impetus to applying all-in-one sensing and memory-computing artificial vision systems.展开更多
Intergrowth ferroelectric semiconductors with excellent spontaneous polarization field are highly promising piezo-photocatalytic candidate materials.In addition,developing structural design and revealing polarization ...Intergrowth ferroelectric semiconductors with excellent spontaneous polarization field are highly promising piezo-photocatalytic candidate materials.In addition,developing structural design and revealing polarization enhancement in-depth mechanism are top priorities.Herein,we introduce the intergrowth ferroelectrics Bi_(7)Ti_(4)NbO_(21)thin-layer nanosheets for piezo-photocatalytic CO_(2)reduction.Density functional theory(DFT)calculations indicate that interlayer lattice mismatch leads to increased tilting and rotation angle of Ti/NbO_(6)octahedra on perovskite-like layers,serving as the main reason for increased polarization.Furthermore,the tilting and rotation angle of the interlayer octahedron further increase under stress,suggesting a stronger driving force generated to facilitate charge carrier separation efficiency.Meanwhile,Bi_(7)Ti_(4)NbO_(21)nanosheets provide abundant active sites to effectively adsorb CO_(2)and acquire sensitive stress response,thereby presenting synergistically advanced piezo-photocatalytic CO_(2)reduction activity with a high CO generation rate of 426.97μmol g^(-1)h^(-1).Our work offers new perspectives and directions for initiating and investigating the mechanisms of high-performance intergrowth piezo-photocatalysts.展开更多
In the realm of optoelectronics,photodetectors play pivotal roles,with applications spanning from high-speed data communication to precise environmental sensing.Despite the advancements,conventional photodetectors gra...In the realm of optoelectronics,photodetectors play pivotal roles,with applications spanning from high-speed data communication to precise environmental sensing.Despite the advancements,conventional photodetectors grapple with challenges with response speed and dark current.In this study,we present a photodetector based on a lateral MoTe_(2)p-n junction,defined by a semi-floating ferroelectric gate.The strong ferroelectric fields and the depletion region of the p-n junction in the device are notably compact,which diminish the carrier transit time,thereby enhancing the speed of the photoelectric response.The non-volatile MoTe_(2)homojunction,under the influence of external gate voltage pulses,can alter the orientation of the intrinsic electric field within the junction.As a photovoltaic detector,it achieves an ultra-low dark current of 20 pA,and a fast photo response of 2μs.The spectral response is extended to the shortwave infrared range at 1550 nm.Furthermore,a logic computing system with light/no light as binary input is designed to convert the current signal to the voltage output.This research not only underscores the versatility of 2D materials in the realm of sophisticated photodetector design but also heralds new avenues for their application in energy-efficient,high-performance optoelectronic devices.展开更多
Recent advances in van der Waals(vdW) ferroelectrics have sparked the development of related heterostructures with non-volatile and field-tunable functionalities. In vdW ferroelectric heterojunctions, the interfacial ...Recent advances in van der Waals(vdW) ferroelectrics have sparked the development of related heterostructures with non-volatile and field-tunable functionalities. In vdW ferroelectric heterojunctions, the interfacial electrical characteristics play a crucial role in determining their performance and functionality. In this study,we explore the interfacial polarization coupling in two-dimensional(2D) ferroelectric heterojunctions by fabricating a graphene/h-BN/CuInP_(2)S_(6)/α-In_(2)Se_(3)/Au ferroelectric field-effect transistor. By varying the gate electric field, the CuInP_(2)S_(6)/α-In_(2)Se_(3) heterojunction displays distinct interfacial polarization coupling states, resulting in significantly different electrical transport behaviors. Under strong gate electric fields, the migration of Cu ions further enhances the interfacial polarization effect, enabling continuous tuning of both the polarization state and carrier concentration in α-In_(2)Se_(3). Our findings offer valuable insights for the development of novel multifunctional devices based on 2D ferroelectric materials.展开更多
Poly(vinylidene-trifluoroethylene) [P(VDF-TrFE)] copolymer films generally demonstrate limited compatibility with organic semiconductors. The material is frequently compromised by exposure to organic semiconductor sol...Poly(vinylidene-trifluoroethylene) [P(VDF-TrFE)] copolymer films generally demonstrate limited compatibility with organic semiconductors. The material is frequently compromised by exposure to organic semiconductor solutions and other fabrication processes utilized in the production of organic ferroelectric transistors. In this study, an organic ferroelectric field effect transistor(OFeFET) with the 6,13-Bis(triisopropylsilylethynyl) pentacene(TIPS-pentacene) channel is fabricated, in which the aluminum oxide(Al_(2)O_(3)) interlayer is used to improve compatibility. The device displays polymorphic memory and synaptic plasticity of long-term potentiation and depression. Furthermore, an artificial neural network constructed using our devices is simulated to succeed in recognizing the MNIST handwritten digit database with a high accuracy of 92.8%. This research offers a viable approach to enhance the compatibility of the organic ferroelectric polymer P(VDF-TrFE) with organic semiconductors.展开更多
Doped HfO_(2)as an emerging ferroelectric material,holds considerable promise for non-volatile memory applications.Epitaxial growth of doped HfO_(2)thin films is widely adopted as an effective technique for revealing ...Doped HfO_(2)as an emerging ferroelectric material,holds considerable promise for non-volatile memory applications.Epitaxial growth of doped HfO_(2)thin films is widely adopted as an effective technique for revealing the intrinsic ferroelectric properties.In this study,based on systematic structural,chemical and electrical investigations,the influences of Mn doping and substrate orientation on ferroelectric properties of Mn-doped HfO_(2)epitaxial thin films are investigated.The results demonstrate that Mn-doped HfO_(2)thin films with orthorhombic phase can be epitaxially grown along[111]out-of-plane direction on both SrTiO_(3)(001)and(110)substrates,and 10%Mn-doping significantly stabilizes the orthorhombic polar phase and enhances the ferroelectric polarization.Interestingly,compared to the films on SrTiO_(3)(001)substrate,the better crystallinity and reduction of oxygen vacancy amount in Mn-doped HfO_(2)films grown on the SrTiO_(3)(110)substrate are observed,which enhance the remanent polarization and reduce the coercive field.It provides an effective approach for the controllable regulation of defects and the enhancement of intrinsic ferroelectricity in HfO_(2)-based materials.展开更多
To address the global energy shortage,hydrogen production as a green energy source has become one of the most prominent research topics over the past decade.Novel and promising ferroelectric materials,exhibiting uniqu...To address the global energy shortage,hydrogen production as a green energy source has become one of the most prominent research topics over the past decade.Novel and promising ferroelectric materials,exhibiting unique spontaneous polarization capabilities,have shown great potential in the field of photocatalytic hydrogen evolution.Among these materials,perovskites represent a significant group of ferroelectrics,possessing both excellent ferroelectric properties and photocatalytic performance.By focusing on perovskites,we analyze the advantages of their built-in electric field for photocatalytic hydrogen evolution,integrating the domain wall structures of ferroelectrics.Furthermore,we summarize how to fully exploit the unique characteristics of ferroelectrics and highlight recent advancements in their application to photocatalytic hydrogen evolution.展开更多
Ferroelectric film materials have attracted significant interest due to their potential for harvesting various forms ofclean energy from natural environmental sources.However,the photoelectric performance of these mat...Ferroelectric film materials have attracted significant interest due to their potential for harvesting various forms ofclean energy from natural environmental sources.However,the photoelectric performance of these materials isfrequently constrained by heat generation during light absorption,resulting in significant thermal losses.Most offerroelectric films produce photocurrent and thermocurrent with opposite polarity,thus weakening the coupledphoto-thermoelectric output of the devices.Here we report on a LaNiO_(3)/BiMn_(2)O_(5)(BMO)/ITO ferroelectric film toproduce photocurrent and thermocurrent with the same polarity.The polarity of the photocurrent generated bythe BMO film is shown to be determined solely by the direction of spontaneous polarization,overcoming thedetrimental effect of Schottky barrier for energy harvesting in device.We propose a new strategy to enhance thecoupling factor,thereby offering valuable new insights for optimizing the utilization of ferroelectric materials inboth light and heat energy applications.展开更多
The performance optimization of materials is an eternal theme and challenge in scientific research,which is reflected in ferroelectric filed to two hot topics of enhancing Curie temperature(TC)and functional versatili...The performance optimization of materials is an eternal theme and challenge in scientific research,which is reflected in ferroelectric filed to two hot topics of enhancing Curie temperature(TC)and functional versatility.The former one vitally determines ferroelectric operational temperature range while the latter would open up new application possibilities.Effective chemical modification or doping strategies on A-site and X-site components have been successfully developed in hybrid organic-inorganic perovskite(HOIP)ferroelectrics,however,the important role of adjusting B-site ions has long been overlooked.Here,we have implemented regulation on the ion radius of the B-site component to successfully obtain two new HOIP ferroelectrics(3-pyrrolinium)BBr_(3)(B=Mn and Ni).Compared to parent(3-pyrrolinium)CdBr_(3),the TC(△T=99 K)was significantly optimized by replacing the Cd^(2+)with smaller Mn^(2+)or Ni^(2+)ions.More strikingly,the introduction of Mn^(2+)and Ni^(2+)ions with octahedral coordination bring out intriguing red emission and magnetism respectively,making the multifunctional integration in a single material for multiple uses.This work provides a feasible strategy for performance optimizing of HOIP ferroelectrics,and would shed light for constructing multifunctional ferroelectrics.展开更多
Two-dimensional perovskite ferroelectric which strongly couple ferroelectricity with semiconducting properties are promising candidates for optoelectronic applications.However,it is still a great challenge to fabricat...Two-dimensional perovskite ferroelectric which strongly couple ferroelectricity with semiconducting properties are promising candidates for optoelectronic applications.However,it is still a great challenge to fabricate self-powered broadband photodetectors with low detection limit.Herein,we successfully realized self-powered broadband photodetection with low detection limit by using a trilayered perovskite ferroelectric(BA)_(2)EA_(2)Pb_(3)I_(10)(1,BA=n-butylamine,EA=ethylamine).Giving to its large spontaneous polarization(5.6μC/cm^(2)),1 exhibits an open-circuit voltage of 0.25 V which provide driving force to separate carriers.Combining with its low dark current(~10^(-14)A)and narrow bandgap(Eg=1.86 e V),1 demonstrates great potential on detecting the broadband weak lights.Thus,a prominent photodetection performance with high open-off ratio(~10^(5)),outstanding responsivity(>10 m A/W),and promising detectivity(>1011Jones),as well as the low detecting limit(~nW/cm^(2))among the wide wavelength from 377 nm to637 nm was realized based on the single crystal of 1.This work demonstrates the great potential of 2D perovskite ferroelectric on self-powered broadband photodetectors.展开更多
Perovskite optoelectronic devices,capitalizing on the exceptional light-matter interaction and semiconductor properties of perovskite materials,have emerged as transformative platforms for energy conversion,informatio...Perovskite optoelectronic devices,capitalizing on the exceptional light-matter interaction and semiconductor properties of perovskite materials,have emerged as transformative platforms for energy conversion,information storage,and photonic technologies.While material innovations and device engineering breakthroughs have propelled remarkable advancements,persistent challenges in operational stability,scalable manufacturing,and batch reproducibility continue to hinder commercial implementation.Recently,molecular ferroelectrics(MOFEs),as a class of materials characterized by polar crystal structures and switchable spontaneous polarization(P_(s)),offer novel pathways to regulate high-efficiency and stable perovskite optoelectronic devices.Here,we systematically review the application of MOFEs into diverse perovskite optoelectronic systems,emphasizing the synergistic effect between P_(s)and optoelectronic properties.We analyze MOFEs-based photodetectors spanning self-powered,X-ray,and polarized-light detectors,detailing how P_(s)and synergistic physical effects optimize device performance.For photovoltaic applications,we elucidate polarizationdriven performance enhancement mechanisms in perovskite solar cells(PSCs),including built-in field amplification,defect passivation,and stability improvement.Furthermore,we envisage the emerging applications of MOFEs in optoelectronic fields such as non-volatile memory,neuromorphic computing,and optical communication.Overall,this review furnishes valuable insights into optoelectronics and future energy.展开更多
Elastic electronics are increasingly prevalent in information storage,smart sensing and health monitoring due to their softness,stretchability and portability.Wearable electronic devices should possess elasticity and ...Elastic electronics are increasingly prevalent in information storage,smart sensing and health monitoring due to their softness,stretchability and portability.Wearable electronic devices should possess elasticity and stretchability that align with biological tissues.Specifically,their materials should be capable of elastic strain up to 50–80%,while the devices themselves must maintain electric stability under strains that accommodate body movements[1].展开更多
Ferroelectrics(FEs)have shown great potential in sensors,actuators,and electrocaloric cooling due to their direct cross-couplings between electric polarization and mechanical,thermal,and dielectric properties[1−3]Comp...Ferroelectrics(FEs)have shown great potential in sensors,actuators,and electrocaloric cooling due to their direct cross-couplings between electric polarization and mechanical,thermal,and dielectric properties[1−3]Compared with oxide FEs,polymer FEs possess good flexible and shape adaptability,making them promising candidates for flexible electronics and biocompatible devices[4].展开更多
Poly(vinylidene fluoride-trifluoroethylene)(P(VDF-TrFE)) is a derivative of polyvinylidene fluoride(PVDF), known for its excellent ferroelectric properties, optical characteristics, chemical stability, and flexibility...Poly(vinylidene fluoride-trifluoroethylene)(P(VDF-TrFE)) is a derivative of polyvinylidene fluoride(PVDF), known for its excellent ferroelectric properties, optical characteristics, chemical stability, and flexibility, making it a promising material for applications in electronic devices. In this study, the polarization switching mechanism of the β-phase of P(VDFTrFE) is investigated using the polarized crystal charge method, along with molecular dynamics simulations. The simulation results show that the saturation polarization value is approximately 5.3 μC/cm^(2), and a coercive field of around 0.5 V/nm is required to switch its polarization states. By fitting the polarization reversal curve with the Kolmogorov–Avrami–Ishibashi model, it is observed that the data in the asymptotic and switching regions closely align with the predictions of the model,and the Avrami index n consistently ranges between 1 and 2. The polarization reversal is completed within approximately10 ps, demonstrating high-speed dynamic behavior. Additionally, we predict that the ferroelectric phase transition occurs between 420 K and 430 K, with stable polarization performance maintained over a wide temperature range, which is consistent with experimental results.展开更多
Based on the principles of thermodynamics, we elucidate the fundamental reasons behind the hysteresis of spontaneous polarization in ferroelectric materials during heating and cooling processes. By utilizing the effec...Based on the principles of thermodynamics, we elucidate the fundamental reasons behind the hysteresis of spontaneous polarization in ferroelectric materials during heating and cooling processes. By utilizing the effective Hamiltonian method in conjuction with the phase-field model, we have successfully reproduced the thermal hysteresis observed in ferroelectric materials during phase transitions. The computational results regarding the electrocaloric effect from these two different computational scales closely align with experimental measurements. Furthermore, we analyze how the first-order ferroelectric phase transition gradually diminishes with an increasing applied electric field, exhibiting characteristics of second-order-like phase transition. By employing the characteristic parameters of thermal hysteresis, we have established a pathway for calculations across different computational scales, thereby providing theoretical support for further investigations into the properties of ferroelectric materials through concurrent multiscale simulations.展开更多
Epitaxial strain is an effective way to control thermoelectricity of a thin film system.In this work,we investigate strain-dependent thermoelectricity of[(SrTiO_(3))_(3)/(SrTi_(0.8)Nb_(0.2)O_(3))_(3)]_(10)superlattice...Epitaxial strain is an effective way to control thermoelectricity of a thin film system.In this work,we investigate strain-dependent thermoelectricity of[(SrTiO_(3))_(3)/(SrTi_(0.8)Nb_(0.2)O_(3))_(3)]_(10)superlattices grown on different substrates,including-0.96%on(LaAlO_(3))_(0.3)(SrAl_(0.5)Ta_(0.5)O_(3))_(0.7)(001)(LSAT),0%on SrTiO_(3)(001)(STO),+0.99%on DyScO_(3)(110)(DSO)and+1.64%on GdScO_(3)(110)(GSO),respectively.Our results show that the highest room-temperature thermoelectricity is achieved when the STO-based superlattice is grown on the DSO substrate with+0.99%tensile strain.This is attributed to the high permittivity and low dielectric loss arising from the ferroelectric domain and electron-phonon coupling,which boost the power factor(PF)to 10.5 mW·m^(-1)·K^(-2)at 300 K.展开更多
Lithium niobate(LN)has remained at the forefront of academic research and industrial applications due to its rich material properties,which include second-order nonlinear optic,electro-optic,and piezoelectric properti...Lithium niobate(LN)has remained at the forefront of academic research and industrial applications due to its rich material properties,which include second-order nonlinear optic,electro-optic,and piezoelectric properties.A further aspect of LN’s versatility stems from the ability to engineer ferroelectric domains with micro and even nano-scale precision in LN,which provides an additional degree of freedom to design acoustic and optical devices with improved performance and is only possible in a handful of other materials.In this review paper,we provide an overview of the domain engineering techniques developed for LN,their principles,and the typical domain size and pattern uniformity they provide,which is important for devices that require high-resolution domain patterns with good reproducibility.It also highlights each technique's benefits,limitations,and adaptability for an application,along with possible improvements and future advancement prospects.Further,the review provides a brief overview of domain visualization methods,which is crucial to gain insights into domain quality/shape and explores the adaptability of the proposed domain engineering methodologies for the emerging thin-film lithium niobate on an insulator platform,which creates opportunities for developing the next generation of compact and scalable photonic integrated circuits and high frequency acoustic devices.展开更多
Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a pro...Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a promising alternative to achieve low power consumption and nonvolatile electric control of magnetic properties.In this paper,a two-dimensional multiferroic van der Waals heterostructure OsCl_(2)/Sc_(2)CO_(2),which is composed of ferromagnetic monolayer OsCl_(2)and ferroelectric monolayer Sc_(2)CO_(2),is studied by first-principles density functional theory.The results show that by reversing the direction of the electric polarization of Sc_(2)CO_(2),OsCl_(2)can be transformed from a semiconductor to a half-metal,demonstrating a nonvolatile electrical manipulation of the heterostructure through ferroelectric polarization.The underlying physical mechanism is explained by band alignments and charge density differences.Furthermore,based on the heterostructure,we construct a multiferroic tunnel junction with a tunnel electroresistance ratio of 3.38×10^(14)%and a tunnel magnetoresistance ratio of 5.04×10^(6)%,allowing control of conduction states via instantaneous electric or magnetic fields.The findings provide a feasible strategy for designing advanced nanodevices based on the giant tunnel electroresistance and tunnel magnetoresistance effects.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11304160the Special Fund for Public Interest of China under Grant No 201510068,and the NUPTFC under Grant No NY215111
文摘Properties of ferroelectric xBiInO3-（1-x）PbTiO3（xBI-（1-x）PT） thin films deposited on（101） SrRuO3/（200）Pt/（200） MgO substrates by rf magnetron sputtering method and effects of deposition conditions are investigated.The structures of the xBI-（1-x）PT films are characterized by x-ray diffraction and scanning electron microscopy.The results indicate that the thin films are grown with mainly（001） orientation. The chemical compositions of the films are analyzed by scanning electron probe and the results indicate that the loss phenomena of Pb and Bi elements depend on the pressure and temperature during the sputtering process.The sputtering parameters including target composition, substrate temperature, and gas pressure are adjusted to obtain optimum sputtering conditions. To decrease leakage currents,2 mol% La2 O3 is doped in the targets. The P-E hysteresis loops show that the optimized xBI-（1-x）PT（x = 0.24） film has high ferroelectricities with remnant polarization2 Pr = 80μC/cm2 and coercive electric field 2 EC = 300 kV/cm. The Curie temperature is about 640℃. The results show that the films have optimum performance and will have wide applications.
基金Project supported by the Natural Science Foundation of Jiangsu Province(Grant Nos.BK20231529 and BK20233001)the National Key Research and Development Program of China(Grant No.2024YFA1409100)+2 种基金the Fundamental Research Funds for the Central Universities(Grant No.0204-14380233)the National Natural Science Foundation of China(Grant Nos.12474170 and 123B2059)the National Postdoctoral Program for Innovative Talents(Grant No.BX20240160)。
文摘Interfacial ferroelectricity is a recently established mechanism for generating spontaneous reversible electric polarization,arising from the charge transfer between stacked van der Waals layered atomic crystals.It has been realized in both naturally formed multilayer crystals and moirésuperlattices.Owing to the large number of material choices and combinations,this approach is highly versatile,greatly expanding the scope of ultrathin ferroelectrics.A key advantage of interfacial ferroelectricity is its potential to couple with preexisting properties of the constituent layers,enabling their electrical manipulation through ferroelectric switching and paving the way for advanced device functionalities.This review article summarizes recent experimental progress in interfacial ferroelectricity,with an emphasis on its coupling with a variety of electronic properties.After introducing the underlying mechanism of interfacial ferroelectricity and the range of material systems discovered to date,we highlight selected examples showcasing ferroelectric control of excitonic optical properties,Berry curvature effects,and superconductivity.We also discuss the challenges and opportunities that await further studies in this field.
基金supported by the National Natural Science Foundation of China(Nos.52371245,12174237,12241403)the National Key Research and Development Program of China(No.2022YFB3505301).
文摘Van der Waals(vdW)ferroelectric-semiconductor heterojunction provides reconfigurable band alignment based on optical/electrical-assisted polarization switching,which shows great potential to construct artificial visual neural systems.However,the mechanical exfoliation fabrication scheme for proof-of-concept demonstrations and fundamental studies is cumbersome and not scalable for practical application.Here,we present a synthetic strategy for the large-scale and high crystallinity growth of planar/verticalα-In_(2)Se_(3)/MoS_(2)heterojunctions by dynamically tuning the growth temperature.Furthermore,based on theα-In_(2)Se_(3)/MoS_(2)heterostructures,photo-synapse devices are designed and fabricated to simulate visual neural systems functions,including multistate storage,optical logic operation,potentiation and depression,paired-pulse facilitation(PPF),short-term memory(STM),long-term memory(LTM),and Learning-Forgetting-Relearning.By coupling the spatiotemporally relevant optical and electric information,the device can mimic the superior biological visual system’s light adaptation and Pavlovian conditioning.This work provides a strategy for dynamically tuning the orientation of ferroelectric-semiconductor heterojunction stacks and will give impetus to applying all-in-one sensing and memory-computing artificial vision systems.
基金support from the Natural Science Foundation of Jiangsu Province(BK20220596)Innovative science and technology platform project of cooperation between Yangzhou City and Yangzhou University,China(No.YZ202026305)+1 种基金Natural Science Foundation of China(21922202,21673202 and 22272147)the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Intergrowth ferroelectric semiconductors with excellent spontaneous polarization field are highly promising piezo-photocatalytic candidate materials.In addition,developing structural design and revealing polarization enhancement in-depth mechanism are top priorities.Herein,we introduce the intergrowth ferroelectrics Bi_(7)Ti_(4)NbO_(21)thin-layer nanosheets for piezo-photocatalytic CO_(2)reduction.Density functional theory(DFT)calculations indicate that interlayer lattice mismatch leads to increased tilting and rotation angle of Ti/NbO_(6)octahedra on perovskite-like layers,serving as the main reason for increased polarization.Furthermore,the tilting and rotation angle of the interlayer octahedron further increase under stress,suggesting a stronger driving force generated to facilitate charge carrier separation efficiency.Meanwhile,Bi_(7)Ti_(4)NbO_(21)nanosheets provide abundant active sites to effectively adsorb CO_(2)and acquire sensitive stress response,thereby presenting synergistically advanced piezo-photocatalytic CO_(2)reduction activity with a high CO generation rate of 426.97μmol g^(-1)h^(-1).Our work offers new perspectives and directions for initiating and investigating the mechanisms of high-performance intergrowth piezo-photocatalysts.
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0580000)Natural Science Foundation of China(62222413,62025405,62105100,62075228 and 62334001)+1 种基金Natural Science Foundation of Shanghai(23ZR1473400)Hundred Talents Program of the Chinese Academy of Sciences。
文摘In the realm of optoelectronics,photodetectors play pivotal roles,with applications spanning from high-speed data communication to precise environmental sensing.Despite the advancements,conventional photodetectors grapple with challenges with response speed and dark current.In this study,we present a photodetector based on a lateral MoTe_(2)p-n junction,defined by a semi-floating ferroelectric gate.The strong ferroelectric fields and the depletion region of the p-n junction in the device are notably compact,which diminish the carrier transit time,thereby enhancing the speed of the photoelectric response.The non-volatile MoTe_(2)homojunction,under the influence of external gate voltage pulses,can alter the orientation of the intrinsic electric field within the junction.As a photovoltaic detector,it achieves an ultra-low dark current of 20 pA,and a fast photo response of 2μs.The spectral response is extended to the shortwave infrared range at 1550 nm.Furthermore,a logic computing system with light/no light as binary input is designed to convert the current signal to the voltage output.This research not only underscores the versatility of 2D materials in the realm of sophisticated photodetector design but also heralds new avenues for their application in energy-efficient,high-performance optoelectronic devices.
基金supported by the Chinese Academy of Sciences Project for Young Scientists in Basic Research(Grant No.YSBR-049)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302800)the Fundamental Research Funds for the Central Universities(Grant No.WK3510000013)。
文摘Recent advances in van der Waals(vdW) ferroelectrics have sparked the development of related heterostructures with non-volatile and field-tunable functionalities. In vdW ferroelectric heterojunctions, the interfacial electrical characteristics play a crucial role in determining their performance and functionality. In this study,we explore the interfacial polarization coupling in two-dimensional(2D) ferroelectric heterojunctions by fabricating a graphene/h-BN/CuInP_(2)S_(6)/α-In_(2)Se_(3)/Au ferroelectric field-effect transistor. By varying the gate electric field, the CuInP_(2)S_(6)/α-In_(2)Se_(3) heterojunction displays distinct interfacial polarization coupling states, resulting in significantly different electrical transport behaviors. Under strong gate electric fields, the migration of Cu ions further enhances the interfacial polarization effect, enabling continuous tuning of both the polarization state and carrier concentration in α-In_(2)Se_(3). Our findings offer valuable insights for the development of novel multifunctional devices based on 2D ferroelectric materials.
基金supported by the National Key Research and Development program of China (Nos. 2024YFA1410700 and 2021YFA1200700)the National Natural Science Foundation of China (Nos. T2222025, 62174053, 62474065 and 52372120)+3 种基金the Natural Science Foundation of Chongqing (CSTB2024NSCQ-JQX0005)the Shanghai Science and Technology Innovation Action Plan (Nos. 24QA2702300 and 24YF2710400)the National Postdoctoral Program (GZB20240225)the Fundamental Research Funds for the Central Universities。
文摘Poly(vinylidene-trifluoroethylene) [P(VDF-TrFE)] copolymer films generally demonstrate limited compatibility with organic semiconductors. The material is frequently compromised by exposure to organic semiconductor solutions and other fabrication processes utilized in the production of organic ferroelectric transistors. In this study, an organic ferroelectric field effect transistor(OFeFET) with the 6,13-Bis(triisopropylsilylethynyl) pentacene(TIPS-pentacene) channel is fabricated, in which the aluminum oxide(Al_(2)O_(3)) interlayer is used to improve compatibility. The device displays polymorphic memory and synaptic plasticity of long-term potentiation and depression. Furthermore, an artificial neural network constructed using our devices is simulated to succeed in recognizing the MNIST handwritten digit database with a high accuracy of 92.8%. This research offers a viable approach to enhance the compatibility of the organic ferroelectric polymer P(VDF-TrFE) with organic semiconductors.
基金supported by the National Natural Science Foundation of China(Grant Nos.52125204,52250281,52422209,92163210,and U21A2066)the Na-tional Key Research and Development Program of China(Grant Nos.2024YFA1208601,2022YFB3807602,and 2022YFB3807604).
文摘Doped HfO_(2)as an emerging ferroelectric material,holds considerable promise for non-volatile memory applications.Epitaxial growth of doped HfO_(2)thin films is widely adopted as an effective technique for revealing the intrinsic ferroelectric properties.In this study,based on systematic structural,chemical and electrical investigations,the influences of Mn doping and substrate orientation on ferroelectric properties of Mn-doped HfO_(2)epitaxial thin films are investigated.The results demonstrate that Mn-doped HfO_(2)thin films with orthorhombic phase can be epitaxially grown along[111]out-of-plane direction on both SrTiO_(3)(001)and(110)substrates,and 10%Mn-doping significantly stabilizes the orthorhombic polar phase and enhances the ferroelectric polarization.Interestingly,compared to the films on SrTiO_(3)(001)substrate,the better crystallinity and reduction of oxygen vacancy amount in Mn-doped HfO_(2)films grown on the SrTiO_(3)(110)substrate are observed,which enhance the remanent polarization and reduce the coercive field.It provides an effective approach for the controllable regulation of defects and the enhancement of intrinsic ferroelectricity in HfO_(2)-based materials.
基金supports from the Scientific Research Foundation of Hunan Provincial Education Department(21A0188,24C0149)the National Natural Science Foundation of China(52400202)+3 种基金Engineering and Technical Center Open Fund of Hunan Provincial Environmental Protection for River-Lake Dredging Pollution Control(EPD202104)Natural Science Foundation of Hunan Province(2023JJ40028,2024JJ6058)Natural Science Foundation of Changsha City(kq2208232)Natural Science Foundation of Hunan Province(2023JJ40033).
文摘To address the global energy shortage,hydrogen production as a green energy source has become one of the most prominent research topics over the past decade.Novel and promising ferroelectric materials,exhibiting unique spontaneous polarization capabilities,have shown great potential in the field of photocatalytic hydrogen evolution.Among these materials,perovskites represent a significant group of ferroelectrics,possessing both excellent ferroelectric properties and photocatalytic performance.By focusing on perovskites,we analyze the advantages of their built-in electric field for photocatalytic hydrogen evolution,integrating the domain wall structures of ferroelectrics.Furthermore,we summarize how to fully exploit the unique characteristics of ferroelectrics and highlight recent advancements in their application to photocatalytic hydrogen evolution.
基金supported by the National Natural Science Foundation of China(grant no.52072041)the Beijing Natural Science Foundation(grant no.JQ21007).
文摘Ferroelectric film materials have attracted significant interest due to their potential for harvesting various forms ofclean energy from natural environmental sources.However,the photoelectric performance of these materials isfrequently constrained by heat generation during light absorption,resulting in significant thermal losses.Most offerroelectric films produce photocurrent and thermocurrent with opposite polarity,thus weakening the coupledphoto-thermoelectric output of the devices.Here we report on a LaNiO_(3)/BiMn_(2)O_(5)(BMO)/ITO ferroelectric film toproduce photocurrent and thermocurrent with the same polarity.The polarity of the photocurrent generated bythe BMO film is shown to be determined solely by the direction of spontaneous polarization,overcoming thedetrimental effect of Schottky barrier for energy harvesting in device.We propose a new strategy to enhance thecoupling factor,thereby offering valuable new insights for optimizing the utilization of ferroelectric materials inboth light and heat energy applications.
基金financially supported by the National Natural Science Foundation of China(Nos.22375182,92056112 and 21991141).
文摘The performance optimization of materials is an eternal theme and challenge in scientific research,which is reflected in ferroelectric filed to two hot topics of enhancing Curie temperature(TC)and functional versatility.The former one vitally determines ferroelectric operational temperature range while the latter would open up new application possibilities.Effective chemical modification or doping strategies on A-site and X-site components have been successfully developed in hybrid organic-inorganic perovskite(HOIP)ferroelectrics,however,the important role of adjusting B-site ions has long been overlooked.Here,we have implemented regulation on the ion radius of the B-site component to successfully obtain two new HOIP ferroelectrics(3-pyrrolinium)BBr_(3)(B=Mn and Ni).Compared to parent(3-pyrrolinium)CdBr_(3),the TC(△T=99 K)was significantly optimized by replacing the Cd^(2+)with smaller Mn^(2+)or Ni^(2+)ions.More strikingly,the introduction of Mn^(2+)and Ni^(2+)ions with octahedral coordination bring out intriguing red emission and magnetism respectively,making the multifunctional integration in a single material for multiple uses.This work provides a feasible strategy for performance optimizing of HOIP ferroelectrics,and would shed light for constructing multifunctional ferroelectrics.
基金financially supported by the National Natural Science Foundation of China(Nos.22435005,22193042,21921001,22305105,52202194,22201284)Natural Science Foundation of Jiangxi Province(No.20224BAB213003)+1 种基金the Natural Science Foundation of Fujian Province(No.2023J05076)Jiangxi Provincial Education Department Science and Technology Research Foundation(No.GJJ2200384)。
文摘Two-dimensional perovskite ferroelectric which strongly couple ferroelectricity with semiconducting properties are promising candidates for optoelectronic applications.However,it is still a great challenge to fabricate self-powered broadband photodetectors with low detection limit.Herein,we successfully realized self-powered broadband photodetection with low detection limit by using a trilayered perovskite ferroelectric(BA)_(2)EA_(2)Pb_(3)I_(10)(1,BA=n-butylamine,EA=ethylamine).Giving to its large spontaneous polarization(5.6μC/cm^(2)),1 exhibits an open-circuit voltage of 0.25 V which provide driving force to separate carriers.Combining with its low dark current(~10^(-14)A)and narrow bandgap(Eg=1.86 e V),1 demonstrates great potential on detecting the broadband weak lights.Thus,a prominent photodetection performance with high open-off ratio(~10^(5)),outstanding responsivity(>10 m A/W),and promising detectivity(>1011Jones),as well as the low detecting limit(~nW/cm^(2))among the wide wavelength from 377 nm to637 nm was realized based on the single crystal of 1.This work demonstrates the great potential of 2D perovskite ferroelectric on self-powered broadband photodetectors.
基金financially supported by the National Natural Science Foundation of China(No.52302229)the State Key Laboratory of Photovoltaic Science and Technology of China(No.202401030301)the Key Lab of Modern Optical Technologies of Education Ministry of China,Soochow University(No.KJS2425)。
文摘Perovskite optoelectronic devices,capitalizing on the exceptional light-matter interaction and semiconductor properties of perovskite materials,have emerged as transformative platforms for energy conversion,information storage,and photonic technologies.While material innovations and device engineering breakthroughs have propelled remarkable advancements,persistent challenges in operational stability,scalable manufacturing,and batch reproducibility continue to hinder commercial implementation.Recently,molecular ferroelectrics(MOFEs),as a class of materials characterized by polar crystal structures and switchable spontaneous polarization(P_(s)),offer novel pathways to regulate high-efficiency and stable perovskite optoelectronic devices.Here,we systematically review the application of MOFEs into diverse perovskite optoelectronic systems,emphasizing the synergistic effect between P_(s)and optoelectronic properties.We analyze MOFEs-based photodetectors spanning self-powered,X-ray,and polarized-light detectors,detailing how P_(s)and synergistic physical effects optimize device performance.For photovoltaic applications,we elucidate polarizationdriven performance enhancement mechanisms in perovskite solar cells(PSCs),including built-in field amplification,defect passivation,and stability improvement.Furthermore,we envisage the emerging applications of MOFEs in optoelectronic fields such as non-volatile memory,neuromorphic computing,and optical communication.Overall,this review furnishes valuable insights into optoelectronics and future energy.
基金supported by generous grants from the Natural Science Foundation of Zhejiang Province(LR24E030003)Zhejiang Province Qianjiang Talent Program(ZJ-QJRC-2020-32).
文摘Elastic electronics are increasingly prevalent in information storage,smart sensing and health monitoring due to their softness,stretchability and portability.Wearable electronic devices should possess elasticity and stretchability that align with biological tissues.Specifically,their materials should be capable of elastic strain up to 50–80%,while the devices themselves must maintain electric stability under strains that accommodate body movements[1].
基金support from the Natural Science Fund for Colleges and Universities in Jiangsu Province(24KJB430029)the Start-up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications(NY224032,NY225006).
文摘Ferroelectrics(FEs)have shown great potential in sensors,actuators,and electrocaloric cooling due to their direct cross-couplings between electric polarization and mechanical,thermal,and dielectric properties[1−3]Compared with oxide FEs,polymer FEs possess good flexible and shape adaptability,making them promising candidates for flexible electronics and biocompatible devices[4].
基金Project supported by the National Key Research and Development Program of China (Grant No. 2021YFA1200700)the National Natural Science Foundation of China (Grant Nos. 11905054, 12275075, and 11704111)the Fundamental Research Funds for the Central Universities of China。
文摘Poly(vinylidene fluoride-trifluoroethylene)(P(VDF-TrFE)) is a derivative of polyvinylidene fluoride(PVDF), known for its excellent ferroelectric properties, optical characteristics, chemical stability, and flexibility, making it a promising material for applications in electronic devices. In this study, the polarization switching mechanism of the β-phase of P(VDFTrFE) is investigated using the polarized crystal charge method, along with molecular dynamics simulations. The simulation results show that the saturation polarization value is approximately 5.3 μC/cm^(2), and a coercive field of around 0.5 V/nm is required to switch its polarization states. By fitting the polarization reversal curve with the Kolmogorov–Avrami–Ishibashi model, it is observed that the data in the asymptotic and switching regions closely align with the predictions of the model,and the Avrami index n consistently ranges between 1 and 2. The polarization reversal is completed within approximately10 ps, demonstrating high-speed dynamic behavior. Additionally, we predict that the ferroelectric phase transition occurs between 420 K and 430 K, with stable polarization performance maintained over a wide temperature range, which is consistent with experimental results.
基金Project supported financially by the National Natural Science Foundation of China (Grant No. 52372100)the National Key Research and Development Program of China (Grant No. 2019YFA0307900)。
文摘Based on the principles of thermodynamics, we elucidate the fundamental reasons behind the hysteresis of spontaneous polarization in ferroelectric materials during heating and cooling processes. By utilizing the effective Hamiltonian method in conjuction with the phase-field model, we have successfully reproduced the thermal hysteresis observed in ferroelectric materials during phase transitions. The computational results regarding the electrocaloric effect from these two different computational scales closely align with experimental measurements. Furthermore, we analyze how the first-order ferroelectric phase transition gradually diminishes with an increasing applied electric field, exhibiting characteristics of second-order-like phase transition. By employing the characteristic parameters of thermal hysteresis, we have established a pathway for calculations across different computational scales, thereby providing theoretical support for further investigations into the properties of ferroelectric materials through concurrent multiscale simulations.
基金supported by the National Key Research&Development Program of China(Grant No.2022YFA1403300)the Innovation Program for Quantum Science and Technology(Grant No.2024ZD0300103)+2 种基金the National Natural Science Foundation of China(Grant Nos.11991060,11427902,12074075,62171136,and 12474165)the Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX01)the Shanghai Municipal Natural Science Foundation(Grant Nos.22ZR1407400,22ZR1408100,and 23ZR1407200)。
文摘Epitaxial strain is an effective way to control thermoelectricity of a thin film system.In this work,we investigate strain-dependent thermoelectricity of[(SrTiO_(3))_(3)/(SrTi_(0.8)Nb_(0.2)O_(3))_(3)]_(10)superlattices grown on different substrates,including-0.96%on(LaAlO_(3))_(0.3)(SrAl_(0.5)Ta_(0.5)O_(3))_(0.7)(001)(LSAT),0%on SrTiO_(3)(001)(STO),+0.99%on DyScO_(3)(110)(DSO)and+1.64%on GdScO_(3)(110)(GSO),respectively.Our results show that the highest room-temperature thermoelectricity is achieved when the STO-based superlattice is grown on the DSO substrate with+0.99%tensile strain.This is attributed to the high permittivity and low dielectric loss arising from the ferroelectric domain and electron-phonon coupling,which boost the power factor(PF)to 10.5 mW·m^(-1)·K^(-2)at 300 K.
基金supported by the Australian Research Council Centre of Excellence in Optical Microcombs for Breakthrough Science COMBS(CE230100006)the Australian Research Council grants DP220100488 and DE230100964funded by the Australian Government.
文摘Lithium niobate(LN)has remained at the forefront of academic research and industrial applications due to its rich material properties,which include second-order nonlinear optic,electro-optic,and piezoelectric properties.A further aspect of LN’s versatility stems from the ability to engineer ferroelectric domains with micro and even nano-scale precision in LN,which provides an additional degree of freedom to design acoustic and optical devices with improved performance and is only possible in a handful of other materials.In this review paper,we provide an overview of the domain engineering techniques developed for LN,their principles,and the typical domain size and pattern uniformity they provide,which is important for devices that require high-resolution domain patterns with good reproducibility.It also highlights each technique's benefits,limitations,and adaptability for an application,along with possible improvements and future advancement prospects.Further,the review provides a brief overview of domain visualization methods,which is crucial to gain insights into domain quality/shape and explores the adaptability of the proposed domain engineering methodologies for the emerging thin-film lithium niobate on an insulator platform,which creates opportunities for developing the next generation of compact and scalable photonic integrated circuits and high frequency acoustic devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.12074213,11574108,and 12104253)the National Key R&D Program of China(Grant No.2022YFA1403103)+2 种基金the Major Basic Program of the Natural Science Foundation of Shandong Province(Grant No.ZR2021ZD01)the Natural Science Foundation of Shandong Provincial(Grant No.ZR2023MA082)the Project of Introduction and Cultivation for Young Innovative Talents in Colleges and Universities of Shandong Province。
文摘Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a promising alternative to achieve low power consumption and nonvolatile electric control of magnetic properties.In this paper,a two-dimensional multiferroic van der Waals heterostructure OsCl_(2)/Sc_(2)CO_(2),which is composed of ferromagnetic monolayer OsCl_(2)and ferroelectric monolayer Sc_(2)CO_(2),is studied by first-principles density functional theory.The results show that by reversing the direction of the electric polarization of Sc_(2)CO_(2),OsCl_(2)can be transformed from a semiconductor to a half-metal,demonstrating a nonvolatile electrical manipulation of the heterostructure through ferroelectric polarization.The underlying physical mechanism is explained by band alignments and charge density differences.Furthermore,based on the heterostructure,we construct a multiferroic tunnel junction with a tunnel electroresistance ratio of 3.38×10^(14)%and a tunnel magnetoresistance ratio of 5.04×10^(6)%,allowing control of conduction states via instantaneous electric or magnetic fields.The findings provide a feasible strategy for designing advanced nanodevices based on the giant tunnel electroresistance and tunnel magnetoresistance effects.
