Polar two-dimensional(2D)perovskites with their excellent semiconductor properties,intrinsic anisotropy,and bulk photovoltaic effect,have emerged as promising candidates for Self-driven polarization-sensitive photodet...Polar two-dimensional(2D)perovskites with their excellent semiconductor properties,intrinsic anisotropy,and bulk photovoltaic effect,have emerged as promising candidates for Self-driven polarization-sensitive photodetectors.However,these self-driven polarized detectors typically require fabrication along the spontaneous polarization direction to maintain the device’s operation in the self-driven mode,which imposes additional limitations.Herein,we demonstrate multidirectional self-driven polarization-sensitive photodetection by constructing 2D perovskite-based asymmetric contact devices,Ag/2D perovskite/C.The built-in electric field,originating from the difference in work functions,acts as the driving force for the separation and transport of photogenerated carriers.Notably,this approach does not necessitate a specific direction,thereby enabling multidirectional self-driven photodetection.Under excitation by linearly polarized light,our devices exhibit impressive polarization-sensitive discrimination in multiple directions,achieving polarization ratios of 3.3 and 3.1 along the a and baxes,respectively.Our work enriches the approaches enabling self-driven polarization-sensitive photodetection,free from the previous limitations.展开更多
In this paper,the collective motion of self-driven robots is studied experimentally and theoretically.In the channel,the flowrate of robots increases with the density linearly,even if the density of the robots tends t...In this paper,the collective motion of self-driven robots is studied experimentally and theoretically.In the channel,the flowrate of robots increases with the density linearly,even if the density of the robots tends to 1.0.There is no abrupt drop in the flowrate,similar to the collective motion of ants.We find that the robots will adjust their velocities by a serial of tiny collisions.The speed-adjustment will affect both robots involved in the collision,and will help to maintain a nearly uniform velocity for the robots.As a result,the flowrate drop will disappear.In the motion,the robots neither gather together nor scatter completely.Instead,they form some clusters to move together.These clusters are not stable during the moving process,but their sizes follow a power-law-alike distribution.We propose a theoretical model to simulate this collective motion process,which can reproduce these behaviors well.Analytic results about the flowrate behavior are also consistent with experiments.展开更多
Ferroelectric materials are promising candidates for ultraviolet photodetectors due to their ferroelectric effect.In this work,a BaTiO_(3)/p-GaN/Au hybrid heterojunction-Schottky self-driven ultraviolet photodetector ...Ferroelectric materials are promising candidates for ultraviolet photodetectors due to their ferroelectric effect.In this work,a BaTiO_(3)/p-GaN/Au hybrid heterojunction-Schottky self-driven ultraviolet photodetector was fabricated with excellent bipolar photoresponse property.At 0 V bias,the direction of the photocurrent can be switched by flipping the depolarization field of BaTiO_(3),which allows the performance of photodetectors to be controlled by the ferroelectric effect.Meanwhile,a relatively large responsivity and a fast response speed can be also observed.In particular,when the depolarization field of BaTiO_(3) is in the same direction of the built-in electric field of the Au/p-GaN Schottky junction(up polarized state),the photodetector exhibits a high responsivity of 18 mA/W at 360 nm,and a fast response speed of<40 ms at 0 V.These findings pave a new way for the preparation of high-performance photodetectors with bipolar photocurrents.展开更多
This paper presents a cascode configuration synchronous rectifier device based on silicon MOSFET and Schottky diode,which can replace traditional power diode directly.This structure has self-driven ability with simple...This paper presents a cascode configuration synchronous rectifier device based on silicon MOSFET and Schottky diode,which can replace traditional power diode directly.This structure has self-driven ability with simple external circuit,and the conduction characteristic is preferable to a power diode.Static characterization and switching behavior analysis of proposed structure are conducted in this paper.The switching process is illustrated in detail using real model which considers the parasitic inductances and the nonlinearity of junction capacitors.The real time internal voltage and current value during switching transition are deduced with the equivalent circuit.To validate the analysis,two voltage specification rectifiers are built.Finally,double-pulse test results and the practical design example verify the performance advantages of proposed structure.展开更多
The self-driven behavior of droplets on a functionalized surface,coupled with wetting gradient and wedge patterns,is systematically investigated using molecular dynamics(MD)simulations.The effects of key factors,inclu...The self-driven behavior of droplets on a functionalized surface,coupled with wetting gradient and wedge patterns,is systematically investigated using molecular dynamics(MD)simulations.The effects of key factors,including wedge angle,wettability,and wetting gradient,on the droplet self-driving effect is revealed from the nanoscale.Results indicate that the maximum velocity of droplets on hydrophobic wedge-shaped surfaces increases with the wedge angle,accompanied by a rapid attenuation of driving force;however,the average velocity decreases with the increased wedge angle.Conversely,droplet movement on hydrophilic wedge-shaped surfaces follows the opposite trend,particularly in terms of average velocity compared to the hydrophobic case.Both wedge-shaped and composite gradient wedge-shaped surfaces are found to induce droplet motion,with droplets exhibiting higher speeds and distances on hydrophobic surfaces compared to hydrophilic surfaces,regardless of surface type.Importantly,the inclusion of wettability gradients significantly influences droplet motion,with hydrophobic composite gradient wedge-shaped surfaces showing considerable improvements in droplet speed and distance compared to their hydrophilic counterparts.By combining suitable wettability gradients with wedge-shaped surfaces,the limitations inherent in the wettability gradient range and wedge-shaped configuration can be mitigated,thereby enhancing droplet speed and distance.The findings presented in this paper offer valuable insights for the design of advanced functional surfaces tailored for manipulating droplets in real-world applications.展开更多
Photodetectors based on two-dimensional(2D) materials have attracted considerable attention because of their unique properties. To further improve the performance of self-driven photodetectors based on van der Waals h...Photodetectors based on two-dimensional(2D) materials have attracted considerable attention because of their unique properties. To further improve the performance of self-driven photodetectors based on van der Waals heterojunctions, a conductive band minimum(CBM) matched self-driven SnS_(2)/WS_(2) van der Waals heterojunction photodetector based on a SiO2/Si substrate has been designed. The device exhibits a positive current at zero voltage under 365 nm laser illumination.This is attributed to the built-in electric field at the interface of the SnS_(2) and WS_(2) layer, which will separate and transport the photogenerated carriers, even at zero bias voltage. In addition, the Al_(2)O_(3) layer is covered by the surface of the SnS_(2)/WS_(2) photodetector to further improve the performance, because the Al_(2)O_(3) layer will introduce tensile stress on the surface of the 2D materials leading to a higher electron concentration and smaller effective mass of electrons in the films. This work provides an idea for the research of self-driven photodetectors based on a van der Waals heterogeneous junction.展开更多
Attributed to its excellent physicochemical properties,graphene(GR)has very active applications in the fields of catalysis,optoelectronic devices,and battery electrode materials.However,until now,regulating the type a...Attributed to its excellent physicochemical properties,graphene(GR)has very active applications in the fields of catalysis,optoelectronic devices,and battery electrode materials.However,until now,regulating the type and density of carriers in GR is still crucial for its practical applications.Here,reduced graphene oxide(RGO)-Bi_(2)Te_(3)heterojunctions doped with different contents were prepared by a simple one-step method.The Bi_(2)Te_(3)materials containing different RGO were made into broadband(365–850 nm)photoelectrochemical-type detectors,and the effects of the doping amount of RGO on the optoelectronic behavior of the devices and the intrinsic operation mechanism of the devices were investigated in detail.The results show that the values of Iph/Idark,Ri,and D*of Bi_(2)Te_(3)/RGO heterojunction devices obtained with 1 mg of RGO doping are 412,6.072 mA/W,and 2.4061010 Jones,respectively.It is anticipated that this work will provide a research basis for future quantitative tuning of the performance of micro-nano devices by GR.展开更多
Swarm Intelligence (SI) is a collective behavior that emerges from interaction between individuals in a group. Typical SI includes fish schooling, ant foraging, bird migration, and so on. A great deal of models have b...Swarm Intelligence (SI) is a collective behavior that emerges from interaction between individuals in a group. Typical SI includes fish schooling, ant foraging, bird migration, and so on. A great deal of models have been introduced to characterize the mechanism of SI. This article reviews several typical models and classifies them into four categories: self-driven particle models, with Boids model as the primary example;pheromone communication models, including the ant colony pheromone model which serves as the foundation for ant colony optimization;leadership decision models, utilizing the hierarchical dynamics model of pigeon flock as a prime instance;empirical research models, which employ the topological rule model of starling flock as a classic model. On this basis, each type of model is elaborated upon in terms of its typical model overview, applications, and model evaluation. More specifically, multi-agent swarm control, path optimization and obstacle avoidance, formation and consensus control, trajectory tracking in the dense crowd and social networks analysis are surveyed in the application of each category, respectively. Furthermore, the more precise and effective modeling techniques for leadership decision and empirical research models are described. Limitations and potential directions for further exploration in the study of SI are presented.展开更多
Thermally chargeable supercapacitors(TCSCs)have unique advantages in the collection,conversion,and storage of thermal energy,contributing to the development of new strategies for thermal energy utilization.2D MXene ma...Thermally chargeable supercapacitors(TCSCs)have unique advantages in the collection,conversion,and storage of thermal energy,contributing to the development of new strategies for thermal energy utilization.2D MXene materials are predicted to be highly promising new thermoelectric materials.Here,we report a self-assembled flexible Ti_(3)C_(2)T_(x) MXenebased TCSC device,using prepared Ti_(3)C_(2)T_(x) MXene as the capacitor electrode and a NaClO_(4)/PEO gel as the electrolyte.We also explore the working mechanism of the TCSCs.The fabricated Ti_(3)C_(2)T_(x)-based TCSCs exhibit an excellent Seebeck coefficient of 11.8 mV∙K^(−1) on average and maintain good cycling stability under various temperature differences.Demonstrations of multiple practical applications show that Ti_(3)C_(2)T_(x) MXene-based TCSC devices are excellent candidates for self-powered integrated electronic devices.展开更多
基金supported by the National Natural Science Foundation of China(22435005,22193042,52202194,21833010,21921001,22175177,21971238,22201284)the Natural Science Foundation of Fujian Province(2023J05076)+1 种基金the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(ZDBS-LY-SLH024)the China Postdoctoral Science Foundation(2022M713152,2023M733501,2023T160646)。
文摘Polar two-dimensional(2D)perovskites with their excellent semiconductor properties,intrinsic anisotropy,and bulk photovoltaic effect,have emerged as promising candidates for Self-driven polarization-sensitive photodetectors.However,these self-driven polarized detectors typically require fabrication along the spontaneous polarization direction to maintain the device’s operation in the self-driven mode,which imposes additional limitations.Herein,we demonstrate multidirectional self-driven polarization-sensitive photodetection by constructing 2D perovskite-based asymmetric contact devices,Ag/2D perovskite/C.The built-in electric field,originating from the difference in work functions,acts as the driving force for the separation and transport of photogenerated carriers.Notably,this approach does not necessitate a specific direction,thereby enabling multidirectional self-driven photodetection.Under excitation by linearly polarized light,our devices exhibit impressive polarization-sensitive discrimination in multiple directions,achieving polarization ratios of 3.3 and 3.1 along the a and baxes,respectively.Our work enriches the approaches enabling self-driven polarization-sensitive photodetection,free from the previous limitations.
基金Project supported by the Key Research and Development Program,China(Grant No.2016YFC0802508)the National Natural Science Foundation of China(Grant Nos.11672289 and 11422221)
文摘In this paper,the collective motion of self-driven robots is studied experimentally and theoretically.In the channel,the flowrate of robots increases with the density linearly,even if the density of the robots tends to 1.0.There is no abrupt drop in the flowrate,similar to the collective motion of ants.We find that the robots will adjust their velocities by a serial of tiny collisions.The speed-adjustment will affect both robots involved in the collision,and will help to maintain a nearly uniform velocity for the robots.As a result,the flowrate drop will disappear.In the motion,the robots neither gather together nor scatter completely.Instead,they form some clusters to move together.These clusters are not stable during the moving process,but their sizes follow a power-law-alike distribution.We propose a theoretical model to simulate this collective motion process,which can reproduce these behaviors well.Analytic results about the flowrate behavior are also consistent with experiments.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.62074148,61875194,11727902,12204474,12304111,and 12304112)the Youth Innovation Promotion Association,Chinese Academy of Sciences (Grant No.2020225)+1 种基金Jilin Province Science Fund (Grant Nos.20220101053JC and 20210101145JC)Jilin Province Young and Middle-Aged Science and Technology Innovation Leaders and Team Project (Grant No.20220508153RC)。
文摘Ferroelectric materials are promising candidates for ultraviolet photodetectors due to their ferroelectric effect.In this work,a BaTiO_(3)/p-GaN/Au hybrid heterojunction-Schottky self-driven ultraviolet photodetector was fabricated with excellent bipolar photoresponse property.At 0 V bias,the direction of the photocurrent can be switched by flipping the depolarization field of BaTiO_(3),which allows the performance of photodetectors to be controlled by the ferroelectric effect.Meanwhile,a relatively large responsivity and a fast response speed can be also observed.In particular,when the depolarization field of BaTiO_(3) is in the same direction of the built-in electric field of the Au/p-GaN Schottky junction(up polarized state),the photodetector exhibits a high responsivity of 18 mA/W at 360 nm,and a fast response speed of<40 ms at 0 V.These findings pave a new way for the preparation of high-performance photodetectors with bipolar photocurrents.
基金supported in part by the National Natural Science Foundation of China (No.51777093)
文摘This paper presents a cascode configuration synchronous rectifier device based on silicon MOSFET and Schottky diode,which can replace traditional power diode directly.This structure has self-driven ability with simple external circuit,and the conduction characteristic is preferable to a power diode.Static characterization and switching behavior analysis of proposed structure are conducted in this paper.The switching process is illustrated in detail using real model which considers the parasitic inductances and the nonlinearity of junction capacitors.The real time internal voltage and current value during switching transition are deduced with the equivalent circuit.To validate the analysis,two voltage specification rectifiers are built.Finally,double-pulse test results and the practical design example verify the performance advantages of proposed structure.
基金supported by the National Natural Science Foundation of China(No.52206073)the University Outstanding Youth Fund Project of Anhui Province(Nos.2022AH020028 and 2022AH030037)+2 种基金the Natural Science Foundation of Anhui Province(Nos.1908085QF292 and 2308085ME173)Anhui Province Outstanding Young Talents Support Program(No.gxyqZD2022058)Guangdong Basic and Applied Basic Research Foundation(Nos.2024A1515011379 and 2023A1515110613).
文摘The self-driven behavior of droplets on a functionalized surface,coupled with wetting gradient and wedge patterns,is systematically investigated using molecular dynamics(MD)simulations.The effects of key factors,including wedge angle,wettability,and wetting gradient,on the droplet self-driving effect is revealed from the nanoscale.Results indicate that the maximum velocity of droplets on hydrophobic wedge-shaped surfaces increases with the wedge angle,accompanied by a rapid attenuation of driving force;however,the average velocity decreases with the increased wedge angle.Conversely,droplet movement on hydrophilic wedge-shaped surfaces follows the opposite trend,particularly in terms of average velocity compared to the hydrophobic case.Both wedge-shaped and composite gradient wedge-shaped surfaces are found to induce droplet motion,with droplets exhibiting higher speeds and distances on hydrophobic surfaces compared to hydrophilic surfaces,regardless of surface type.Importantly,the inclusion of wettability gradients significantly influences droplet motion,with hydrophobic composite gradient wedge-shaped surfaces showing considerable improvements in droplet speed and distance compared to their hydrophilic counterparts.By combining suitable wettability gradients with wedge-shaped surfaces,the limitations inherent in the wettability gradient range and wedge-shaped configuration can be mitigated,thereby enhancing droplet speed and distance.The findings presented in this paper offer valuable insights for the design of advanced functional surfaces tailored for manipulating droplets in real-world applications.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.61974144,62004127,and 12074263)the Science and Technology Foundation of Shenzhen (Grant No.JSGG20191129114216474)the “National” Taipei University of Technology–Shenzhen University Joint Research Program,China (Grant No.2020009)。
文摘Photodetectors based on two-dimensional(2D) materials have attracted considerable attention because of their unique properties. To further improve the performance of self-driven photodetectors based on van der Waals heterojunctions, a conductive band minimum(CBM) matched self-driven SnS_(2)/WS_(2) van der Waals heterojunction photodetector based on a SiO2/Si substrate has been designed. The device exhibits a positive current at zero voltage under 365 nm laser illumination.This is attributed to the built-in electric field at the interface of the SnS_(2) and WS_(2) layer, which will separate and transport the photogenerated carriers, even at zero bias voltage. In addition, the Al_(2)O_(3) layer is covered by the surface of the SnS_(2)/WS_(2) photodetector to further improve the performance, because the Al_(2)O_(3) layer will introduce tensile stress on the surface of the 2D materials leading to a higher electron concentration and smaller effective mass of electrons in the films. This work provides an idea for the research of self-driven photodetectors based on a van der Waals heterogeneous junction.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFA0705201)the National Natural Science Foundation of China(Grant No.U2032129).
文摘Attributed to its excellent physicochemical properties,graphene(GR)has very active applications in the fields of catalysis,optoelectronic devices,and battery electrode materials.However,until now,regulating the type and density of carriers in GR is still crucial for its practical applications.Here,reduced graphene oxide(RGO)-Bi_(2)Te_(3)heterojunctions doped with different contents were prepared by a simple one-step method.The Bi_(2)Te_(3)materials containing different RGO were made into broadband(365–850 nm)photoelectrochemical-type detectors,and the effects of the doping amount of RGO on the optoelectronic behavior of the devices and the intrinsic operation mechanism of the devices were investigated in detail.The results show that the values of Iph/Idark,Ri,and D*of Bi_(2)Te_(3)/RGO heterojunction devices obtained with 1 mg of RGO doping are 412,6.072 mA/W,and 2.4061010 Jones,respectively.It is anticipated that this work will provide a research basis for future quantitative tuning of the performance of micro-nano devices by GR.
基金co-supported by the National Natural Science Foundation of China(No.61873017)the Academic Excellence Foundation of Beihang University for PhD Students,China.
文摘Swarm Intelligence (SI) is a collective behavior that emerges from interaction between individuals in a group. Typical SI includes fish schooling, ant foraging, bird migration, and so on. A great deal of models have been introduced to characterize the mechanism of SI. This article reviews several typical models and classifies them into four categories: self-driven particle models, with Boids model as the primary example;pheromone communication models, including the ant colony pheromone model which serves as the foundation for ant colony optimization;leadership decision models, utilizing the hierarchical dynamics model of pigeon flock as a prime instance;empirical research models, which employ the topological rule model of starling flock as a classic model. On this basis, each type of model is elaborated upon in terms of its typical model overview, applications, and model evaluation. More specifically, multi-agent swarm control, path optimization and obstacle avoidance, formation and consensus control, trajectory tracking in the dense crowd and social networks analysis are surveyed in the application of each category, respectively. Furthermore, the more precise and effective modeling techniques for leadership decision and empirical research models are described. Limitations and potential directions for further exploration in the study of SI are presented.
基金supported by National Natural Science Foundation of China(62474019)Beijing Natural Science Foundation(L223006).
文摘Thermally chargeable supercapacitors(TCSCs)have unique advantages in the collection,conversion,and storage of thermal energy,contributing to the development of new strategies for thermal energy utilization.2D MXene materials are predicted to be highly promising new thermoelectric materials.Here,we report a self-assembled flexible Ti_(3)C_(2)T_(x) MXenebased TCSC device,using prepared Ti_(3)C_(2)T_(x) MXene as the capacitor electrode and a NaClO_(4)/PEO gel as the electrolyte.We also explore the working mechanism of the TCSCs.The fabricated Ti_(3)C_(2)T_(x)-based TCSCs exhibit an excellent Seebeck coefficient of 11.8 mV∙K^(−1) on average and maintain good cycling stability under various temperature differences.Demonstrations of multiple practical applications show that Ti_(3)C_(2)T_(x) MXene-based TCSC devices are excellent candidates for self-powered integrated electronic devices.
