On-chip focusing of plasmons in graded-index lenses is important for imaging,lithography,signal processing,and optical interconnects at the deep subwavelength nanoscale.However,owing to the inherent strong wavelength ...On-chip focusing of plasmons in graded-index lenses is important for imaging,lithography,signal processing,and optical interconnects at the deep subwavelength nanoscale.However,owing to the inherent strong wavelength dispersion of plasmonic materials,the on-chip focusing of plasmons suffers from severe chromatic aberrations.With the well-established planar dielectric grating,a graded-index waveguide array lens(GIWAL)is proposed to support the excitation and propagation of acoustic graphene plasmon polaritons(AGPPs)and to achieve the achromatic on-chip focusing of the AGPPs with a focus as small as about 2%of the operating wavelength in the frequency band from 10 to 20 THz,benefiting from the wavelength-independent index profile of the GIWAL.An analytical theory is provided to understand the on-chip focusing of the AGPPs and other beam evolution behaviors,such as self-focusing,self-collimation,and pendulum effects of Gaussian beams as well as spatial inversions of digital optical signals.Furthermore,the possibility of the GIWAL to invert spatially broadband digital optical signals is demonstrated,indicating the potential value of the GIWAL in broadband digital communication and signal processing.展开更多
Real-time acquisition of human pulse signals in daily life is clinically important for cardiovascular disease monitoring and diagnosis.Here,we propose a smart photonic wristband for pulse signal monitoring based on sp...Real-time acquisition of human pulse signals in daily life is clinically important for cardiovascular disease monitoring and diagnosis.Here,we propose a smart photonic wristband for pulse signal monitoring based on speckle pattern analysis with a polymer optical fiber(POF)integrated into a sports wristband.Several different speckle pattern processing algorithms and POFs with different core diameters were evaluated.The results indicated that the smart photonic wristband had a high signal-to-noise ratio and low latency,with the measurement error controlled at approximately 3.7%.This optimized pulse signal could be used for further medical diagnosis and was capable of objectively monitoring subtle pulse signal changes,such as the pulse waveform at different positions of Cunkou and pulse waveforms before and after exercise.With the assistance of artificial intelligence(AI),functions such as gesture recognition have been realized through the established prediction model by processing pulse signals,in which the recognition accuracy reaches 95%.Our AI-assisted smart photonic wristband has potential applications for clinical treatment of cardiovascular diseases and home monitoring,paving the way for medical Internet of Things-enabled smart systems.展开更多
Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allo...Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allow metal halide perovskite to be employed in a wide variety of applications. This article provides a holistic review over the current progress and future prospects of metal halide perovskite materials in representative promising applications, including traditional optoelectronic devices(solar cells, light-emitting diodes, photodetectors, lasers), and cutting-edge technologies in terms of neuromorphic devices(artificial synapses and memristors) and pressure-induced emission. This review highlights the fundamentals, the current progress and the remaining challenges for each application, aiming to provide a comprehensive overview of the development status and a navigation of future research for metal halide perovskite materials and devices.展开更多
Perovskites have been widely utilized as active materials in various optoelectronic devices, e.g. light-emitting diodes(LEDs), photodetectors(PDs), and solar cells(SCs), etc., due to their facile processability and ou...Perovskites have been widely utilized as active materials in various optoelectronic devices, e.g. light-emitting diodes(LEDs), photodetectors(PDs), and solar cells(SCs), etc., due to their facile processability and outstanding optoelectronic properties.展开更多
Reconfigurable intelligent surface(RIS)employs passive beamforming to control the wireless propagation channel,which benefits the wireless communication capacity and the received energy efficiency of wireless power tr...Reconfigurable intelligent surface(RIS)employs passive beamforming to control the wireless propagation channel,which benefits the wireless communication capacity and the received energy efficiency of wireless power transfer(WPT)systems.Such beamforming schemes are classified as discrete and non-convex integer program-ming problems.In this paper,we propose a Monte-Carlo(MC)based random energy passive beamforming of RIS to achieve the maximum received power of electromagnetic(EM)WPT systems.Generally,the Gibbs sampling and re-sampling methods are employed to generate phase shift vector samples.And the sample with the maximum received power is considered the optimal solution.In order to adapt to the application scenarios,we develop two types of passive beamforming algorithms based on such MC sampling methods.The first passive beamforming uses an approximation of the integer programming as the initial sample,which is calculated based on the channel information.And the second one is a purely randomized algorithm with the only total received power feedback.The proposed methods present several advantages for RIS control,e.g.,fast convergence,easy implementation,robustness to the channel noise,and limited feedback requirement,and they are applicable even if the channel information is unknown.According to the simulation results,our proposed methods outperform other approxi-mation and genetic algorithms.With our methods,the WPT system even significantly improves the power effi-ciency in the nonline-of-sight(NLOS)environment.展开更多
We demonstrate digital and analog devices with an Ag/MPS_(3)/Au structure based on layered MPS_(3)(M=Mn,Co,Ni)2 D materials.All devices show the bipolar behavior of resistive switching.In addition,Ag/MnPS_(3)/Au and A...We demonstrate digital and analog devices with an Ag/MPS_(3)/Au structure based on layered MPS_(3)(M=Mn,Co,Ni)2 D materials.All devices show the bipolar behavior of resistive switching.In addition,Ag/MnPS_(3)/Au and Ag/NiPS_(3)/Au devices show synaptic characteristics of potentiation and depression.The digital and analog characteristics of resistance states enable Ag/MPS_(3)/Au devices to work as both binary memory and artificial synapse devices.The Ag/MPS_(3)/Au memory devices are promising for applications of flexible eye-like and brain-like systems on a chip when they are integrated with photodetectors and FETs composed of full MPS_(3) materials.展开更多
Tungsten oxides(WO_(3))are widely recognized as multifunctional systems owing to the existence of rich polymorphs.These diverse phases exhibit distinct octahedra-tilting patterns,generating substantial tunnels that ar...Tungsten oxides(WO_(3))are widely recognized as multifunctional systems owing to the existence of rich polymorphs.These diverse phases exhibit distinct octahedra-tilting patterns,generating substantial tunnels that are ideally suited for iontronics.However,a quantitative comprehension regarding the impact of distinct phases on the kinetics of intercalated conducting ions remains lacking.Herein,we employ first-principles calculations to explore the spatial and orientational correlations of ion transport inγ-and h-WO_(3),shedding light on the relationship between diffusion barriers and the size of the conducting ions.Our findings reveal that different types and concentrations of alkali-metals induce distinct and continuous lattice distortions in WO_(3)polymorphs.Specifically,γ-WO_(3)is more appropriate to accommodate Li+ions,exhibiting a diffusion barrier and coefficient of 0.25 eV and 9.31×10^(-8)cm^(2)s^(-1),respectively.Conversely,h-WO_(3)features unidirectional and sizeable tunnels that facilitate the transport of K+ions with an even lower barrier and a high coefficient of 0.11 e V and 2.12×10^(-5)cm^(2)s^(-1),respectively.Furthermore,the introduction of alkali-metal into WO_(3)tunnels tends to introduce n-type conductivity by contributing s-electrons to the unoccupied W 5d states,resulting in enhanced conductivity and tunable electronic structures.These alkali metals in WO_(3)tunnels are prone to charge transfer,forming small polaronic states and modulating the light absorption in the visible and nearinfrared regions.These tunable electronic and optical properties,combined with the high diffusion coefficient,underscore the potential of WO_(3)in applications such as artificial synapses and chromogenic devices.展开更多
The electrocaloric effect(ECE),known for its environmentally friendly characteristics,holds significant promise for advancing next-generation solid-state refrigeration technologies.Achieving a large ECE along with a w...The electrocaloric effect(ECE),known for its environmentally friendly characteristics,holds significant promise for advancing next-generation solid-state refrigeration technologies.Achieving a large ECE along with a wide working temperature range near room temperature remains a key developmental goal.In this study,we successfully obtained a substantial ECE of 1.78 K and an extensive working temperature range of 103 K(AT>1.52 K)near room temperature in CaZrO_(3)-modified BaTiO_(3) lead-free ferroelectric ceramics.Furthermore,this achievement was verified using direct methods.The piezoresponse force microscopy(PFM)results suggest that the broad temperature range is attributed to the formation of ferroelectric microdomains and polar nanoregions(PNRs).Furthermore,X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible(UV-Vis)spectroscopy reveal a decrease in the oxygen vacancy concentration and an increase in the bandgap for higher CaZrO_(3) doping levels.These changes synergistically enhance the maximum applied electric field,helping to achieve a high-performance EcE near room temperature.This research presents a straightforward and effective approach for achieving high-performance ECEs in BaTiOg lead-free ceramics,offering promising prospects for application in next-generation solid-state refrigeration technologies.展开更多
A conductive,elastic,and biocompatible hybrid network hydrogel was prepared by cross-linking of locust bean gum,polyvinyl alcohol,and carbon nanotubes,yielding a rough top surface and smooth bottom surface.The merging...A conductive,elastic,and biocompatible hybrid network hydrogel was prepared by cross-linking of locust bean gum,polyvinyl alcohol,and carbon nanotubes,yielding a rough top surface and smooth bottom surface.The merging of the two pieces of hydrogel flat face to flat face forms a highly elastic hydrogel with double-rough surfaces.A piezoresistive sensor assembled with the double-rough surface hydrogel sandwiched between two carbon cloth electrodes exhibits a high sensitivity(20.5 kPa^(-1),0-1kPa),a broad detection range(0.1-100 kPa)and a reliable response for 1000 cycles.The rough contact area between the hydrogels and the carbon cloth is found critical in achieving ultra-high sensitivities in the low-pressure range.Moreover,further monolithic integration of the sensor with a flexible solid-state zinc ion battery ensures the self-powering of the sensor for various human motions detection applications.展开更多
Two-dimensional(2D) van der Waals(vdW) materials have extraordinary thermal properties due to the effect of quantum confinement, making them promising for thermoelectric energy conversion and thermal management in mic...Two-dimensional(2D) van der Waals(vdW) materials have extraordinary thermal properties due to the effect of quantum confinement, making them promising for thermoelectric energy conversion and thermal management in microelectronic devices.In this review, the mechanism of phonon anharmonicity originating from three-and four-phonon interactions is derived. The phonon anharmonicity of 2D vdW materials, involving the Grüneisen parameter, phonon lifetime, and thermal conductivity, is summarized and derived in detail. The size-dependent thermal conductivity of representative 2D vdW materials is discussed experimentally and theoretically. This review will present fundamental and advanced knowledge on how to evaluate the phonon anharmonicity in 2D vdW materials, which will aid the design of new structures and materials for applications related to energy transfer and conversion.展开更多
Ultraviolet(UV)photodetectors are extensively adopted in the fields of the Internet of Things,optical communications and imaging.Nowadays,with broadening the application scope of UV photodetectors,developing integrate...Ultraviolet(UV)photodetectors are extensively adopted in the fields of the Internet of Things,optical communications and imaging.Nowadays,with broadening the application scope of UV photodetectors,developing integrated devices with more functionalities rather than basic photo-detecting ability are highly required and have been triggered ever-growing interest in scientific and industrial communities.Ferroelectric thin films have become a potential candidate in the field of UV detection due to their wide bandgap and unique photovoltaic characteristics.Additionally,ferroelectric thin films perform excellent dielectric,piezoelectric,pyroelectric,acousto-optic effects,etc.,which can satisfy the demand for the diversified development of UV detectors.In this review,according to the different roles of ferroelectric thin films in the device,the UV photodetectors based on ferroelectric films are classified into ferroelectric depolarization field driven type,ferroelectric depolarization field and built-in electric field co-driven type,and ferroelectric field enhanced type.These three types of ferroelectric UV photodetectors have great potential and are expected to promote the development of a new generation of UV detection technology.At the end of the paper,the advantages and challenges of three types of ferroelectric UV photodetectors are summarized,and the possible development direction in the future is proposed.展开更多
Vehicular Edge Computing(VEC)brings the computational resources in close proximity to the service requestors and thus supports explosive computing demands from smart vehicles.However,the limited computing capability o...Vehicular Edge Computing(VEC)brings the computational resources in close proximity to the service requestors and thus supports explosive computing demands from smart vehicles.However,the limited computing capability of VEC cannot simultaneously respond to large amounts of offloading requests,thus restricting the performance of VEC system.Besides,a mass of traffic data can incur tremendous pressure on the front-haul links between vehicles and the edge server.To strengthen the performance of VEC,in this paper we propose to place services beforehand at the edge server,e.g.,by deploying the services/tasks-oriented data(e.g.,related libraries and databases)in advance at the network edge,instead of downloading them from the remote data center or offloading them from vehicles during the runtime.In this paper,we formulate the service placement problem in VEC to minimize the average response latency for all requested services along the slotted timeline.Specifically,the time slot spanned optimization problem is converted into per-slot optimization problems based on the Lyapunov optimization.Then a greedy heuristic is introduced to the drift-plus-penalty-based algorithm for seeking the approximate solution.The simulation results reveal its advantages over others in terms of optimal values and our strategy can satisfy the long-term energy constraint.展开更多
Wearable pressure sensors made from conductive hydrogels hold significant potential in health monitoring.However,limited pressure range(Pa to hundreds of kPa)and inadequate antibacterial properties restrict their prac...Wearable pressure sensors made from conductive hydrogels hold significant potential in health monitoring.However,limited pressure range(Pa to hundreds of kPa)and inadequate antibacterial properties restrict their practical applications in diagnostic and health evaluation.Herein,a wearable high-performance pressure sensor was assembled using a facilely prepared porous chitosan-based hydrogel,which was constructed from commercial phenolphthalein particles as a sacrificial template.The relationship between the porosity of hydrogels and sensing performance of sensors was systematically explored.Herein,the wearable pressure sensor,featuring an optimized porosity of hydrogels,exhibits an ultrawide sensing capacity from 4.83 Pa to 250 k Pa(range-to-limit ratio of 51,760)and high sensitivity throughout high pressure ranges(0.7 kPa~(-1),120–250 kPa).The presence of chitosan endows these hydrogels with outstanding antibacterial performance against E.coli and S.aureus,making them ideal candidates for use in wearable electronics.These features allow for a practical approach to monitor full-range human motion using a single device with a simple structure.展开更多
As one of the most promising materials for two-dimensional transition metal chalcogenides(2D TMDs),molybdenum diselenide(MoSe_(2))has great potential in photodetectors due to its excellent properties like tunable band...As one of the most promising materials for two-dimensional transition metal chalcogenides(2D TMDs),molybdenum diselenide(MoSe_(2))has great potential in photodetectors due to its excellent properties like tunable bandgap,high carrier mobility,and excellent air stability.Although 2D MoSe_(2)-based photodetectors have been reported to exhibit admired performance,the large-area 2D MoSe_(2)layers are difficult to be achieved via conventional synthesis methods,which severely impedes its future applications.Here,we present the controllable growth of large-area 2D MoSe_(2)layers over 3.5-inch with excellent homogeneity by a simple post-selenization route.Further,a high-quality n-MoSe_(2)/p-Si van der Waals(vdW)heterojunction device is in-situ fabricated by directly growing 2D n-MoSe_(2)layers on the patterned p-Si substrate,which shows a self-driven broadband photoresponse ranging from ultraviolet to mid-wave infrared with an impressive responsivity of 720.5 mA·W^(−1),a high specific detectivity of 10^(13) Jones,and a fast response time to follow nanosecond pulsed optical signal.In addition,thanks to the inch-level 2D MoSe_(2)layers,a 4×4 integrated heterojunction device array is achieved,which has demonstrated good uniformity and satisfying imaging capability.The large-area 2D MoSe_(2)layer and its heterojunction device array have great promise for high-performance photodetection and imaging applications in integrated optoelectronic systems.展开更多
Optical color filters are widely applied in many areas including display,imaging,sensing,holography,energy harvest,and measurement.Traditional dye-based color filters have drawbacks such as environmental hazards and i...Optical color filters are widely applied in many areas including display,imaging,sensing,holography,energy harvest,and measurement.Traditional dye-based color filters have drawbacks such as environmental hazards and instability under high temperature and ultraviolet radiation.With advances in nanotechnology,structural color filters,which are based on the interaction of light with designed nanostructures,are able to overcome the drawbacks.Also,it is possible to fabricate structural color filters using standard complementary metal-oxide-semiconductor(CMOS)fabrication facilities with low cost and high volume.In this work,metasurface-based subtractive color filters(SCFs)are demonstrated on 12-inch(300-mm)glass wafers using a CMOS-compatible fabrication process.In order to make the transmissive-type SCF on a transparent glass wafer,an in-house developed layer transfer process is used to solve the glass wafer handling issue in fabrication tools.Three different heights of embedded silicon nanopillars(110,170,and 230 nm)are found to support magnetic dipole resonances.With pillar height and pitch variation,SCFs with different displayed colors are achieved.Based on the resonance wavelength,the displayed color of the metasurface is verified within the red-yellow-blue color wheel.The simulation and measurement results are compared and discussed.The work provides an alternative design for high efficiency color filters on a CMOS-compatible platform,and paves the way towards mass-producible large-area metasurfaces.展开更多
With the advent and rapid development of the transformation optics and metamaterials,invisibility cloaks have captivated much attention in recent years.While most cloaking schemes suffer from limited bandwidth,the car...With the advent and rapid development of the transformation optics and metamaterials,invisibility cloaks have captivated much attention in recent years.While most cloaking schemes suffer from limited bandwidth,the carpet cloak,which can hide an object on a reflecting plane,can operate over a broadband frequency range.However,the carpet cloaks experimentally realized thus far still have several limitations.For example,the quasi-conformal mapping carpet cloak leads to a lateral shift of the reflected light ray,while the birefringent carpet cloak only works for a specific polarization.In this work,we propose a conformal transformation scheme to tackle these two problems simultaneously.As an example,we design a mid-infrared carpet cloak in a silicon platform and demonstrate its polarization-insensitive property as well as the minimized lateral shift over a broad frequency band from 24 to 28.3 THz.展开更多
基金supported in part by the National Natural Science Foundation of China(Grant No.62105376)the Guangdong Zhujiang Project(Grant Nos.2021ZT09X070 and 2021QN02X488).The authors declare no competing financial interests。
文摘On-chip focusing of plasmons in graded-index lenses is important for imaging,lithography,signal processing,and optical interconnects at the deep subwavelength nanoscale.However,owing to the inherent strong wavelength dispersion of plasmonic materials,the on-chip focusing of plasmons suffers from severe chromatic aberrations.With the well-established planar dielectric grating,a graded-index waveguide array lens(GIWAL)is proposed to support the excitation and propagation of acoustic graphene plasmon polaritons(AGPPs)and to achieve the achromatic on-chip focusing of the AGPPs with a focus as small as about 2%of the operating wavelength in the frequency band from 10 to 20 THz,benefiting from the wavelength-independent index profile of the GIWAL.An analytical theory is provided to understand the on-chip focusing of the AGPPs and other beam evolution behaviors,such as self-focusing,self-collimation,and pendulum effects of Gaussian beams as well as spatial inversions of digital optical signals.Furthermore,the possibility of the GIWAL to invert spatially broadband digital optical signals is demonstrated,indicating the potential value of the GIWAL in broadband digital communication and signal processing.
基金financial supports from National Key R&D Program of China (2022YFE0140400)National Natural Science Foundation of China(62003046, 62111530238)+7 种基金Guangdong Basic and Applied Basic Research Foundation (2021A1515011997)The Supplemental Funds for Major Scientific Research Projects of Beijing Normal University,Zhuhai(ZHPT2023007)Special project in key field of Guangdong Provincial Department of Education (2021ZDZX1050)The Innovation Team Project of Guangdong Provincial Department of Education (2021KCXTD014)Fundação para a Ciência e a Tecnologia (FCT) through the 2021.00667CEECIND (iAqua project)PTDC/EEI-EEE/0415/2021 (DigiAqua project)The project i3N,UIDB/50025/2020 n&UIDP/50025/2020, financed by national funds through the FCT/MEC
文摘Real-time acquisition of human pulse signals in daily life is clinically important for cardiovascular disease monitoring and diagnosis.Here,we propose a smart photonic wristband for pulse signal monitoring based on speckle pattern analysis with a polymer optical fiber(POF)integrated into a sports wristband.Several different speckle pattern processing algorithms and POFs with different core diameters were evaluated.The results indicated that the smart photonic wristband had a high signal-to-noise ratio and low latency,with the measurement error controlled at approximately 3.7%.This optimized pulse signal could be used for further medical diagnosis and was capable of objectively monitoring subtle pulse signal changes,such as the pulse waveform at different positions of Cunkou and pulse waveforms before and after exercise.With the assistance of artificial intelligence(AI),functions such as gesture recognition have been realized through the established prediction model by processing pulse signals,in which the recognition accuracy reaches 95%.Our AI-assisted smart photonic wristband has potential applications for clinical treatment of cardiovascular diseases and home monitoring,paving the way for medical Internet of Things-enabled smart systems.
基金the National Key Research and Development Program of China (2022YFB3803300)the open research fund of Songshan Lake Materials Laboratory (2021SLABFK02)the National Natural Science Foundation of China (21961160720)。
文摘Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allow metal halide perovskite to be employed in a wide variety of applications. This article provides a holistic review over the current progress and future prospects of metal halide perovskite materials in representative promising applications, including traditional optoelectronic devices(solar cells, light-emitting diodes, photodetectors, lasers), and cutting-edge technologies in terms of neuromorphic devices(artificial synapses and memristors) and pressure-induced emission. This review highlights the fundamentals, the current progress and the remaining challenges for each application, aiming to provide a comprehensive overview of the development status and a navigation of future research for metal halide perovskite materials and devices.
基金financial support from Guangdong Basic and Applied Basic Research Foundation (2021A1515012198)the Science and Technology Program of Guangzhou (202102021084)+4 种基金the support from Songshan Lake Materials Laboratory (Y0D1051F211)the Key Project of the Joint Funds of Guangdong and Dongguan (2021B1515120034)the open research fund of Songshan Lake Materials Laboratory (2021SLABFK02)the National Key Research and Development Program of China (2017YFA0206600)the National Natural Science Foundation of China (51773045, 21772030, 51922032, and 21961160720) for financial support。
文摘Perovskites have been widely utilized as active materials in various optoelectronic devices, e.g. light-emitting diodes(LEDs), photodetectors(PDs), and solar cells(SCs), etc., due to their facile processability and outstanding optoelectronic properties.
基金supported by National Nature Science Foundation of China(No.62171484)Zhuhai Fundamental and Application Research(No.ZH22017003210006PWC)Fundamental Research Funds for the Central Universities(No.21621420).
文摘Reconfigurable intelligent surface(RIS)employs passive beamforming to control the wireless propagation channel,which benefits the wireless communication capacity and the received energy efficiency of wireless power transfer(WPT)systems.Such beamforming schemes are classified as discrete and non-convex integer program-ming problems.In this paper,we propose a Monte-Carlo(MC)based random energy passive beamforming of RIS to achieve the maximum received power of electromagnetic(EM)WPT systems.Generally,the Gibbs sampling and re-sampling methods are employed to generate phase shift vector samples.And the sample with the maximum received power is considered the optimal solution.In order to adapt to the application scenarios,we develop two types of passive beamforming algorithms based on such MC sampling methods.The first passive beamforming uses an approximation of the integer programming as the initial sample,which is calculated based on the channel information.And the second one is a purely randomized algorithm with the only total received power feedback.The proposed methods present several advantages for RIS control,e.g.,fast convergence,easy implementation,robustness to the channel noise,and limited feedback requirement,and they are applicable even if the channel information is unknown.According to the simulation results,our proposed methods outperform other approxi-mation and genetic algorithms.With our methods,the WPT system even significantly improves the power effi-ciency in the nonline-of-sight(NLOS)environment.
基金Project supported by the National Key R&D Program of China(Grant Nos.2017YFA0206200 and 2018YFB2202601)the National Natural Science Foundation of China(Grant Nos.61674173,61834005,and 61902443)。
文摘We demonstrate digital and analog devices with an Ag/MPS_(3)/Au structure based on layered MPS_(3)(M=Mn,Co,Ni)2 D materials.All devices show the bipolar behavior of resistive switching.In addition,Ag/MnPS_(3)/Au and Ag/NiPS_(3)/Au devices show synaptic characteristics of potentiation and depression.The digital and analog characteristics of resistance states enable Ag/MPS_(3)/Au devices to work as both binary memory and artificial synapse devices.The Ag/MPS_(3)/Au memory devices are promising for applications of flexible eye-like and brain-like systems on a chip when they are integrated with photodetectors and FETs composed of full MPS_(3) materials.
基金supported by the Guangdong Basic and Applied Basic Research Foundation(Grant No.2021B1515120025)the Guangdong Province International Science and Technology Cooperation Research Project(Grant No.2023A0505050101)+3 种基金the National Natural Science Foundation of China(Grant No.22022309)the Science and Technology Development Fund from Macao SAR(Grant Nos.0120/2023/RIA2,0085/2023/ITP2,and FDCT-0163/2019/A3)the Natural Science Foundation of Guangdong Province,China(Grant No.2021A1515010024)the University of Macao(Grant No.MYRG2020-00075-IAPME)。
文摘Tungsten oxides(WO_(3))are widely recognized as multifunctional systems owing to the existence of rich polymorphs.These diverse phases exhibit distinct octahedra-tilting patterns,generating substantial tunnels that are ideally suited for iontronics.However,a quantitative comprehension regarding the impact of distinct phases on the kinetics of intercalated conducting ions remains lacking.Herein,we employ first-principles calculations to explore the spatial and orientational correlations of ion transport inγ-and h-WO_(3),shedding light on the relationship between diffusion barriers and the size of the conducting ions.Our findings reveal that different types and concentrations of alkali-metals induce distinct and continuous lattice distortions in WO_(3)polymorphs.Specifically,γ-WO_(3)is more appropriate to accommodate Li+ions,exhibiting a diffusion barrier and coefficient of 0.25 eV and 9.31×10^(-8)cm^(2)s^(-1),respectively.Conversely,h-WO_(3)features unidirectional and sizeable tunnels that facilitate the transport of K+ions with an even lower barrier and a high coefficient of 0.11 e V and 2.12×10^(-5)cm^(2)s^(-1),respectively.Furthermore,the introduction of alkali-metal into WO_(3)tunnels tends to introduce n-type conductivity by contributing s-electrons to the unoccupied W 5d states,resulting in enhanced conductivity and tunable electronic structures.These alkali metals in WO_(3)tunnels are prone to charge transfer,forming small polaronic states and modulating the light absorption in the visible and nearinfrared regions.These tunable electronic and optical properties,combined with the high diffusion coefficient,underscore the potential of WO_(3)in applications such as artificial synapses and chromogenic devices.
基金This work was financially supported by the Science and Technology Plan of Guangxi(Nos.AA21238001,ZY22096019,AA21077012,AA22068080,and AA23023027l)the Key R&D Program of Shandong Province(No.2022CXGC020203)+8 种基金the National Natural Science Foundation of China(Nos.12264012,62271362,and 12304120)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(CAST)(No.2021QNRC001)the Natural Science Foundation of Guangdong Province(No.2022A1515111013)the Science and Technology Plan of Guilin(Nos.2022H03 and ZY20220101)the Guangxi Key Laboratory of Manufacturing System&Advanced Manufacturing Technology(No.22-35-4-S011)the National Natural Science Foundation of China(Nos.52272105 and 52202130)the NSFC-Guangdong Joint Fund(No.U1501246)the Dongguan City Frontier Research Project(No.2019622101006)the Advanced Energy Science and Technology Guangdong Provincial Laboratory Foshan Branch-Foshan Xianhu Laboratory Open Fund-Key Project(No.XHT2020-011).
文摘The electrocaloric effect(ECE),known for its environmentally friendly characteristics,holds significant promise for advancing next-generation solid-state refrigeration technologies.Achieving a large ECE along with a wide working temperature range near room temperature remains a key developmental goal.In this study,we successfully obtained a substantial ECE of 1.78 K and an extensive working temperature range of 103 K(AT>1.52 K)near room temperature in CaZrO_(3)-modified BaTiO_(3) lead-free ferroelectric ceramics.Furthermore,this achievement was verified using direct methods.The piezoresponse force microscopy(PFM)results suggest that the broad temperature range is attributed to the formation of ferroelectric microdomains and polar nanoregions(PNRs).Furthermore,X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible(UV-Vis)spectroscopy reveal a decrease in the oxygen vacancy concentration and an increase in the bandgap for higher CaZrO_(3) doping levels.These changes synergistically enhance the maximum applied electric field,helping to achieve a high-performance EcE near room temperature.This research presents a straightforward and effective approach for achieving high-performance ECEs in BaTiOg lead-free ceramics,offering promising prospects for application in next-generation solid-state refrigeration technologies.
基金supported by the National Natural Science Foundation of China (No.62101605)the Shenzhen Science and Technology Innovation Committee (No.JCYJ20190806145609284)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University (Grant No.22qntd1501).
文摘A conductive,elastic,and biocompatible hybrid network hydrogel was prepared by cross-linking of locust bean gum,polyvinyl alcohol,and carbon nanotubes,yielding a rough top surface and smooth bottom surface.The merging of the two pieces of hydrogel flat face to flat face forms a highly elastic hydrogel with double-rough surfaces.A piezoresistive sensor assembled with the double-rough surface hydrogel sandwiched between two carbon cloth electrodes exhibits a high sensitivity(20.5 kPa^(-1),0-1kPa),a broad detection range(0.1-100 kPa)and a reliable response for 1000 cycles.The rough contact area between the hydrogels and the carbon cloth is found critical in achieving ultra-high sensitivities in the low-pressure range.Moreover,further monolithic integration of the sensor with a flexible solid-state zinc ion battery ensures the self-powering of the sensor for various human motions detection applications.
基金supported by the 100 Talents Program of Sun Yat-sen University (Grant No. 76220-18841201)the National Natural Science Foundation of China (Grant No. 22022309)+2 种基金the Natural Science Foundation of Guangdong Province, China (Grant No. 2021A1515010024)the University of Macao (Grant Nos. SRG2019-00179-IAPME, and MYRG2020-00075IAPME)the Science and Technology Development Fund from Macao SAR (Grant No. FDCT-0163/2019/A3)。
文摘Two-dimensional(2D) van der Waals(vdW) materials have extraordinary thermal properties due to the effect of quantum confinement, making them promising for thermoelectric energy conversion and thermal management in microelectronic devices.In this review, the mechanism of phonon anharmonicity originating from three-and four-phonon interactions is derived. The phonon anharmonicity of 2D vdW materials, involving the Grüneisen parameter, phonon lifetime, and thermal conductivity, is summarized and derived in detail. The size-dependent thermal conductivity of representative 2D vdW materials is discussed experimentally and theoretically. This review will present fundamental and advanced knowledge on how to evaluate the phonon anharmonicity in 2D vdW materials, which will aid the design of new structures and materials for applications related to energy transfer and conversion.
基金supported by the Guang Dong Basic and Applied Basic Research Foundation,China(2021B1515120025)。
文摘Ultraviolet(UV)photodetectors are extensively adopted in the fields of the Internet of Things,optical communications and imaging.Nowadays,with broadening the application scope of UV photodetectors,developing integrated devices with more functionalities rather than basic photo-detecting ability are highly required and have been triggered ever-growing interest in scientific and industrial communities.Ferroelectric thin films have become a potential candidate in the field of UV detection due to their wide bandgap and unique photovoltaic characteristics.Additionally,ferroelectric thin films perform excellent dielectric,piezoelectric,pyroelectric,acousto-optic effects,etc.,which can satisfy the demand for the diversified development of UV detectors.In this review,according to the different roles of ferroelectric thin films in the device,the UV photodetectors based on ferroelectric films are classified into ferroelectric depolarization field driven type,ferroelectric depolarization field and built-in electric field co-driven type,and ferroelectric field enhanced type.These three types of ferroelectric UV photodetectors have great potential and are expected to promote the development of a new generation of UV detection technology.At the end of the paper,the advantages and challenges of three types of ferroelectric UV photodetectors are summarized,and the possible development direction in the future is proposed.
基金supported by National Natural Science Foundation of China(No.62071327)Tianjin Science and Technology Planning Project(No.22ZYYYJC00020)。
文摘Vehicular Edge Computing(VEC)brings the computational resources in close proximity to the service requestors and thus supports explosive computing demands from smart vehicles.However,the limited computing capability of VEC cannot simultaneously respond to large amounts of offloading requests,thus restricting the performance of VEC system.Besides,a mass of traffic data can incur tremendous pressure on the front-haul links between vehicles and the edge server.To strengthen the performance of VEC,in this paper we propose to place services beforehand at the edge server,e.g.,by deploying the services/tasks-oriented data(e.g.,related libraries and databases)in advance at the network edge,instead of downloading them from the remote data center or offloading them from vehicles during the runtime.In this paper,we formulate the service placement problem in VEC to minimize the average response latency for all requested services along the slotted timeline.Specifically,the time slot spanned optimization problem is converted into per-slot optimization problems based on the Lyapunov optimization.Then a greedy heuristic is introduced to the drift-plus-penalty-based algorithm for seeking the approximate solution.The simulation results reveal its advantages over others in terms of optimal values and our strategy can satisfy the long-term energy constraint.
基金supported by the National Natural Science Foundation of China(Grant No.62101605)Zhuhai Fundamental and Application Research(Grant No.2220004002896)+1 种基金Guangdong Introducing Innovative and Entrepreneurial Teams Program(Grant No.2019ZT08Z656)Shenzhen Science and Technology Program(Grant No.KQTD20190929-172522248)。
文摘Wearable pressure sensors made from conductive hydrogels hold significant potential in health monitoring.However,limited pressure range(Pa to hundreds of kPa)and inadequate antibacterial properties restrict their practical applications in diagnostic and health evaluation.Herein,a wearable high-performance pressure sensor was assembled using a facilely prepared porous chitosan-based hydrogel,which was constructed from commercial phenolphthalein particles as a sacrificial template.The relationship between the porosity of hydrogels and sensing performance of sensors was systematically explored.Herein,the wearable pressure sensor,featuring an optimized porosity of hydrogels,exhibits an ultrawide sensing capacity from 4.83 Pa to 250 k Pa(range-to-limit ratio of 51,760)and high sensitivity throughout high pressure ranges(0.7 kPa~(-1),120–250 kPa).The presence of chitosan endows these hydrogels with outstanding antibacterial performance against E.coli and S.aureus,making them ideal candidates for use in wearable electronics.These features allow for a practical approach to monitor full-range human motion using a single device with a simple structure.
基金This work was financially supported by the National Key R&D Program of China(No.2022YFB2803900)the National Natural Science Foundation of China(Nos.U2004165,U22A20138,and 11974016)+1 种基金the Natural Science Foundation of Henan Province,China(No.202300410376)Key Research and Development Program(social development)of Jiangsu Province(No.BE2021667).
文摘As one of the most promising materials for two-dimensional transition metal chalcogenides(2D TMDs),molybdenum diselenide(MoSe_(2))has great potential in photodetectors due to its excellent properties like tunable bandgap,high carrier mobility,and excellent air stability.Although 2D MoSe_(2)-based photodetectors have been reported to exhibit admired performance,the large-area 2D MoSe_(2)layers are difficult to be achieved via conventional synthesis methods,which severely impedes its future applications.Here,we present the controllable growth of large-area 2D MoSe_(2)layers over 3.5-inch with excellent homogeneity by a simple post-selenization route.Further,a high-quality n-MoSe_(2)/p-Si van der Waals(vdW)heterojunction device is in-situ fabricated by directly growing 2D n-MoSe_(2)layers on the patterned p-Si substrate,which shows a self-driven broadband photoresponse ranging from ultraviolet to mid-wave infrared with an impressive responsivity of 720.5 mA·W^(−1),a high specific detectivity of 10^(13) Jones,and a fast response time to follow nanosecond pulsed optical signal.In addition,thanks to the inch-level 2D MoSe_(2)layers,a 4×4 integrated heterojunction device array is achieved,which has demonstrated good uniformity and satisfying imaging capability.The large-area 2D MoSe_(2)layer and its heterojunction device array have great promise for high-performance photodetection and imaging applications in integrated optoelectronic systems.
基金Agency for Science,Technology and Research[RIE2020 Advanced Manufacturing and Engineering(AME),Programmatic Grant(A18A7b0058)]。
文摘Optical color filters are widely applied in many areas including display,imaging,sensing,holography,energy harvest,and measurement.Traditional dye-based color filters have drawbacks such as environmental hazards and instability under high temperature and ultraviolet radiation.With advances in nanotechnology,structural color filters,which are based on the interaction of light with designed nanostructures,are able to overcome the drawbacks.Also,it is possible to fabricate structural color filters using standard complementary metal-oxide-semiconductor(CMOS)fabrication facilities with low cost and high volume.In this work,metasurface-based subtractive color filters(SCFs)are demonstrated on 12-inch(300-mm)glass wafers using a CMOS-compatible fabrication process.In order to make the transmissive-type SCF on a transparent glass wafer,an in-house developed layer transfer process is used to solve the glass wafer handling issue in fabrication tools.Three different heights of embedded silicon nanopillars(110,170,and 230 nm)are found to support magnetic dipole resonances.With pillar height and pitch variation,SCFs with different displayed colors are achieved.Based on the resonance wavelength,the displayed color of the metasurface is verified within the red-yellow-blue color wheel.The simulation and measurement results are compared and discussed.The work provides an alternative design for high efficiency color filters on a CMOS-compatible platform,and paves the way towards mass-producible large-area metasurfaces.
基金Ministry of Education-Singapore(MOE 2018-T2-2-189(S),MOE2018-T2-1-176)National Research Foundation Singapore(NRF-CRP18-2017-02,NRFCRP22-2019-0006)+1 种基金Agency for Science,Technology and Research(A18A7b0058,A20E5c0095)National Natural Science Foundation of China(61871127).
文摘With the advent and rapid development of the transformation optics and metamaterials,invisibility cloaks have captivated much attention in recent years.While most cloaking schemes suffer from limited bandwidth,the carpet cloak,which can hide an object on a reflecting plane,can operate over a broadband frequency range.However,the carpet cloaks experimentally realized thus far still have several limitations.For example,the quasi-conformal mapping carpet cloak leads to a lateral shift of the reflected light ray,while the birefringent carpet cloak only works for a specific polarization.In this work,we propose a conformal transformation scheme to tackle these two problems simultaneously.As an example,we design a mid-infrared carpet cloak in a silicon platform and demonstrate its polarization-insensitive property as well as the minimized lateral shift over a broad frequency band from 24 to 28.3 THz.
