Plasmonic nanoantennas provide unique opportunities for precise control of light–matter coupling in surface-enhanced infrared absorption(SEIRA)spectroscopy,but most of the resonant systems realized so far suffer from...Plasmonic nanoantennas provide unique opportunities for precise control of light–matter coupling in surface-enhanced infrared absorption(SEIRA)spectroscopy,but most of the resonant systems realized so far suffer from the obstacles of low sensitivity,narrow bandwidth,and asymmetric Fano resonance perturbations.Here,we demonstrated an overcoupled resonator with a high plasmon-molecule coupling coefficient(μ)(OC-Hμresonator)by precisely controlling the radiation loss channel,the resonator-oscillator coupling channel,and the frequency detuning channel.We observed a strong dependence of the sensing performance on the coupling state,and demonstrated that OC-Hμresonator has excellent sensing properties of ultra-sensitive(7.25%nm^(−1)),ultra-broadband(3–10μm),and immune asymmetric Fano lineshapes.These characteristics represent a breakthrough in SEIRA technology and lay the foundation for specific recognition of biomolecules,trace detection,and protein secondary structure analysis using a single array(array size is 100×100μm^(2)).In addition,with the assistance of machine learning,mixture classification,concentration prediction and spectral reconstruction were achieved with the highest accuracy of 100%.Finally,we demonstrated the potential of OC-Hμresonator for SARS-CoV-2 detection.These findings will promote the wider application of SEIRA technology,while providing new ideas for other enhanced spectroscopy technologies,quantum photonics and studying light–matter interactions.展开更多
On-chip spectrometers with high compactness and portability enable new applications in scientific research and industrial development.Fourier transform(FT)spectrometers have the potential to realize a high signal-to-n...On-chip spectrometers with high compactness and portability enable new applications in scientific research and industrial development.Fourier transform(FT)spectrometers have the potential to realize a high signal-to-noise ratio.Here we propose and demonstrate a generalized design for high-performance on-chip FT spectrometers.The spectrometer is based on the dynamic in-plane reconfiguration of a waveguide coupler enabled by an integrated comb-drive actuator array.The electrostatic actuation intrinsically features ultra-low power consumption.The coupling gap is crucial to the spectral resolution.The in-plane reconfiguration surmounts the lithography accuracy limitation of the coupling gap,boosting the resolution to 0.2 nm for dual spectral spikes over a large bandwidth of 100 nm(1.5–1.6μm)within a compact footprint of 75μm×1000μm.Meanwhile,the in-plane tuning range can be large enough for arbitrary wavelengths to ensure the effectiveness of spectrum reconstruction.As a result,the proposed spectrometer can be easily transplanted to other operation bands by simply scaling the structural parameters.As a proof-of-concept,a mid-infrared spectrometer is further demonstrated with a dual-spike reconstruction resolution of 1.5 nm and a bandwidth of 300 nm(4–4.3μm).展开更多
Wearable and flexible electronics are shaping our life with their unique advantages of light weight,good compliance,and desirable comfortability.With marching into the era of Internet of Things(IoT),numerous sensor no...Wearable and flexible electronics are shaping our life with their unique advantages of light weight,good compliance,and desirable comfortability.With marching into the era of Internet of Things(IoT),numerous sensor nodes are distributed throughout networks to capture,process,and transmit diverse sensory information,which gives rise to the demand on self-powered sensors to reduce the power consumption.Meanwhile,the rapid development of artificial intelligence(AI)and fifth-generation(5G)technologies provides an opportunity to enable smart-decision making and instantaneous data transmission in IoT systems.Due to continuously increased sensor and dataset number,conventional computing based on von Neumann architecture cannot meet the needs of brain-like high-efficient sensing and computing applications anymore.Neuromorphic electronics,drawing inspiration from the human brain,provide an alternative approach for efficient and low-power-consumption information processing.Hence,this review presents the general technology roadmap of self-powered sensors with detail discussion on their diversified applications in healthcare,human machine interactions,smart homes,etc.Via leveraging AI and virtual reality/augmented reality(VR/AR)techniques,the development of single sensors to intelligent integrated systems is reviewed in terms of step-by-step system integration and algorithm improvement.In order to realize efficient sensing and computing,brain-inspired neuromorphic electronics are next briefly discussed.Last,it concludes and highlights both challenges and opportunities from the aspects of materials,minimization,integration,multimodal information fusion,and artificial sensory system.展开更多
Metal-organic frameworks(MOFs)have been extensively used for gas sorption,storage and separation owing to ultrahigh porosity,exceptional thermal stability,and wide structural diversity.However,when it comes to ultra-l...Metal-organic frameworks(MOFs)have been extensively used for gas sorption,storage and separation owing to ultrahigh porosity,exceptional thermal stability,and wide structural diversity.However,when it comes to ultra-low concentration gas detection,technical bottlenecks of MOFs appear due to the poor adsorption capacity at ppm-/ppblevel concentration and the limited sensitivity for signal transduction.Here,we present hybrid MOF-polymer physi-chemisorption mechanisms integrated with infrared(IR)nanoantennas for highly selective and ultrasensitive CO_(2) detection.To improve the adsorption capacity for trace amounts of gas molecules,MOFs are decorated with amino groups to introduce the chemisorption while maintaining the structural integrity for physisorption.Additionally,leveraging all major optimization methods,a multi-hotspot strategy is proposed to improve the sensitivity of nanoantennas by enhancing the near field and engineering the radiative and absorptive loss.As a benefit,we demonstrate the competitive advantages of our strategy against the state-of-the-art miniaturized IR CO_(2) sensors,including low detection limit,high sensitivity(0.18%/ppm),excellent reversibility(variation within 2%),and high selectivity(against C_(2)H_(5)OH,CH_(3)OH,N_(2)).This work provides valuable insights into the integration of advanced porous materials and nanophotonic devices,which can be further adopted in ultra-low concentration gas monitoring in industry and environmental applications.展开更多
Wind energy is a promising renewable energy source for a low-carbon society.This study is to develop a fully packaged vortexinduced vibration triboelectric nanogenerator(VIV-TENG)for scavenging wind energy.The VIV-TEN...Wind energy is a promising renewable energy source for a low-carbon society.This study is to develop a fully packaged vortexinduced vibration triboelectric nanogenerator(VIV-TENG)for scavenging wind energy.The VIV-TENG consists of a wind vane,internal power generation unit,an external frame,four springs,a square cylinder and a circular turntable.The internal power generation unit consists of polytetrafluoroethylene(PTFE)balls,a honeycomb frame and two copper electrodes.Different from most of the previous wind energy harvesting TENGs,the bouncing PTFE balls are fully packaged in the square cylinder.The distinct design separates the process of contact electrification from the external environment,and at the same time avoids the frictional wear of the ordinary wind energy harvesting TENGs.The corresponding VIV parameters are investigated to evaluate their influence on the vibration behaviors and the energy output.Resonant state of the VIV-TENG corresponds to the high output performance from the VIV-TENG.The distinct,robust structure ensures the full-packaged VIV-TENG can harvest wind energy from arbitrary directions and even in undesirable weather conditions.The study proposes a novel TENG configuration for harvesting wind energy and the VIV-TENG proves promising powering micro-electro-mechanical appliances.展开更多
In the past few years,triboelectric nanogenerator-based(TENG-based)hybrid generators and systems have experienced a widespread and flourishing development,ranging among almost every aspect of our lives,e.g.,from indus...In the past few years,triboelectric nanogenerator-based(TENG-based)hybrid generators and systems have experienced a widespread and flourishing development,ranging among almost every aspect of our lives,e.g.,from industry to consumer,outdoor to indoor,and wearable to implantable applications.Although TENG technology has been extensively investigated for mechanical energy harvesting,most developed TENGs still have limitations of small output current,unstable power generation,and low energy utilization rate of multisource energies.To harvest the ubiquitous/coexisted energy forms including mechanical,thermal,and solar energy simultaneously,a promising direction is to integrate TENG with other transducing mechanisms,e.g.,electromagnetic generator,piezoelectric nanogenerator,pyroelectric nanogenerator,thermoelectric generator,and solar cell,forming the hybrid generator for synergetic single-source and multisource energy harvesting.The resultant TENG-based hybrid generators utilizing integrated transducing mechanisms are able to compensate for the shortcomings of each mechanism and overcome the above limitations,toward achieving a maximum,reliable,and stable output generation.Hence,in this review,we systematically introduce the key technologies of the TENG-based hybrid generators and hybridized systems,in the aspects of operation principles,structure designs,optimization strategies,power management,and system integration.The recent progress of TENG-based hybrid generators and hybridized systems for the outdoor,indoor,wearable,and implantable applications is also provided.Lastly,we discuss our perspectives on the future development trend of hybrid generators and hybridized systems in environmental monitoring,human activity sensation,human-machine interaction,smart home,healthcare,wearables,implants,robotics,Internet of things(IoT),and many other fields.展开更多
In metaverse,a digital-twin smart home is a vital platform for immersive communication between the physical and virtual world.Triboelectric nanogenerators(TENGs)sensors contribute substantially to providing smart-home...In metaverse,a digital-twin smart home is a vital platform for immersive communication between the physical and virtual world.Triboelectric nanogenerators(TENGs)sensors contribute substantially to providing smart-home monitoring.However,TENG deployment is hindered by its unstable out-put under environment changes.Herein,we develop a digital-twin smart home using a robust all-TENG based information mat(InfoMat),which consists of an in-home mat array and an entry mat.The interdigital electrodes design allows environment-insensitive ratiometric readout from the mat array to can-cel the commonly experienced environmental variations.Arbitrary position sensing is also achieved because of the interval arrangement of the mat pixels.Concurrently,the two-channel entry mat generates multi-modality informa-tion to aid the 10-user identification accuracy to increase from 93% to 99% compared to the one-channel case.Furthermore,a digital-twin smart home is visualized by real-time projecting the information in smart home to virtual reality,including access authorization,position,walking trajectory,dynamic activities/sports,and so on.展开更多
The Schottky contact which is a crucial interface between semiconductors and metals is becoming increasingly significant in nano-semiconductor devices. A Schottky barrier, also known as the energy barrier, controls th...The Schottky contact which is a crucial interface between semiconductors and metals is becoming increasingly significant in nano-semiconductor devices. A Schottky barrier, also known as the energy barrier, controls the depletion width and carrier transport across the metal–semiconductor interface.Controlling or adjusting Schottky barrier height(SBH) has always been a vital issue in the successful operation of any semiconductor device. This review provides a comprehensive overview of the static and dynamic adjustment methods of SBH, with a particular focus on the recent advancements in nanosemiconductor devices. These methods encompass the work function of the metals, interface gap states,surface modification, image-lowering effect, external electric field, light illumination, and piezotronic effect. We also discuss strategies to overcome the Fermi-level pinning effect caused by interface gap states, including van der Waals contact and 1D edge metal contact. Finally, this review concludes with future perspectives in this field.展开更多
Water droplets help life in nature survive,thrive,and evolve.With water droplet serv-ing as one of the indispensable elements in the Internet of Things(IoT),many droplet-oriented technologies,such as microfluidics,dro...Water droplets help life in nature survive,thrive,and evolve.With water droplet serv-ing as one of the indispensable elements in the Internet of Things(IoT),many droplet-oriented technologies,such as microfluidics,droplet manipulation,electrowetting,and energy harvesting,make rapid progress driven by material science,computer science,and medicine.Droplet-based wearable devices are endowed with advantages such as flexibility,sensing ability,and automation for various parameter detection.Besides,the continuous exploration of droplet manipulation has led to the emergence of a wide variety of manipulation methods.Meanwhile,electrowetting that utilizes exter-nal fields modifying liquid–solid surfaces has found its applications in various areas,including droplet transportation,microfabrication,and healthcare.The energy gener-ation from water droplets also presents exciting opportunities for the development of novel electricity generators.These approaches for droplet utilization underscore the immense potentials and versatilities of droplet-based technologies in the IoT land-scape.Hence,this mini review presents the fundamental droplet-based technologies by summarizing their working mechanisms and methods,device structures,and appli-cations.Given the challenges in materials,fabrication,and system integration,this review shows the overall development roadmap in terms of improved functionality and performance and highlights the opportunities toward multifunctional,self-sustainable,and intelligent systems,which is called for IoT construction.展开更多
The past few years have witnessed the significant impacts of wearable electronics/photonics on various aspects of our daily life,for example,healthcare monitoring and treatment,ambient monitoring,soft robotics,prosthe...The past few years have witnessed the significant impacts of wearable electronics/photonics on various aspects of our daily life,for example,healthcare monitoring and treatment,ambient monitoring,soft robotics,prosthetics,flexible display,communication,human-machine interactions,and so on.According to the development in recent years,the next-generation wearable electronics and photonics are advancing rapidly toward the era of artificial intelligence(AI)and internet of things(IoT),to achieve a higher level of comfort,convenience,connection,and intelligence.Herein,this review provides an opportune overview of the recent progress in wearable electronics,photonics,and systems,in terms of emerging materials,transducing mechanisms,structural configurations,applications,and their further integration with other technologies.First,development of general wearable electronics and photonics is summarized for the applications of physical sensing,chemical sensing,humanmachine interaction,display,communication,and so on.Then self-sustainable wearable electronics/photonics and systems are discussed based on system integration with energy harvesting and storage technologies.Next,technology fusion of wearable systems and AI is reviewed,showing the emergence and rapid development of intelligent/smart systems.In the last section of this review,perspectives about the future development trends of the next-generation wearable electronics/photonics are provided,that is,toward multifunctional,self-sustainable,and intelligent wearable systems in the AI/IoT era.展开更多
The neural interface is a key component in wireless brain–computer prostheses.In this study,we demonstrate that a unique three-dimensional(3D)microneedle electrode on a flexible mesh substrate,which can be fabricated...The neural interface is a key component in wireless brain–computer prostheses.In this study,we demonstrate that a unique three-dimensional(3D)microneedle electrode on a flexible mesh substrate,which can be fabricated without complicated micromachining techniques,is conformal to the tissues with minimal invasiveness.Furthermore,we demonstrate that it can be applied to different functional layers in the nervous system without length limitation.The microneedle electrode is fabricated using drawing lithography technology from biocompatible materials.In this approach,the profile of a 3D microneedle electrode array is determined by the design of a two-dimensional(2D)pattern on the mask,which can be used to access different functional layers in different locations of the brain.Due to the sufficient stiffness of the electrode and the excellent flexibility of the mesh substrate,the electrode can penetrate into the tissue with its bottom layer fully conformal to the curved brain surface.Then,the exposed contact at the end of the microneedle electrode can successfully acquire neural signals from the brain.展开更多
For human beings of different ages and physical abilities, the inherent balance control system is ubiquitous and active to prevent falling, especially in motion states. A hybridized electromagnetic-triboelectric nanog...For human beings of different ages and physical abilities, the inherent balance control system is ubiquitous and active to prevent falling, especially in motion states. A hybridized electromagnetic-triboelectric nanogenerator (HETNG) is prepared to harvest biomechanical energy during human balance control processes and achieve significant monitoring functions. The HETNG is composed of a symmetrical pendulum structure and a cylinder magnet rolling inside. Four coils are divided into two groups which form into two electromagnetic generators (EMGs). Besides, two spatial electrodes attached to the inner wall constitute a freestanding mode triboelectric nanogenerator (TENG). With a rectification circuit, the HETNG presents a high output power with a peak value of 0.55 W at a load of 160 Ω. Along with human balance control processes during walking, the HETNG can harvest biomechanical energy at different positions on the trunk. Moreover, the HETNG applied in artificial limb has been preliminarily simulated with the positions on thigh and foot, for monitoring the actions of squat and stand up, and lifting the leg up and down. For the elder that walks slowly with a walking aid, the HETNG equipped on the walking aid can help to record the motions of forwarding and unexpected falling, which is useful for calling for help. This work shows the potential of biomechanical energy-driven HETNG for powering portable electronics and monitoring human motions, also shows significant concerns to people lacked action capability or disabled.展开更多
Photonic integrated circuits(PICs)provide a promising platform for miniaturized on-chip optical systems for communication,computation,and sensing applications.The dense integration of photonic components is one of the...Photonic integrated circuits(PICs)provide a promising platform for miniaturized on-chip optical systems for communication,computation,and sensing applications.The dense integration of photonic components is one of the keys to exploit the advantages of PIC.Although light focusing is a fundamental and indispensable function in PICs,focusing light at the micro/nanometer-scale is challenging.Here,a bigradient on-chip metalens(BOML)is proposed to achieve ultrasmall focal lengths and spot sizes at the subwavelength scale for dense PICs.The design of BOML combines gradient geometry and gradient refractive index into one metalens by simultaneously engineering the length and width of subwavelength silicon slots.With a small device footprint of only 168μm,the BOML achieves efficient on-chip focusing with the recordbreaking figure-of-merits,which are the ratio of wavelength to focal length/spot size(0.268 and 2.83)and numerical aperture(1.78).Leveraging on the Fresnel design,the footprint of BOML is further reduced by 55.1%,and the numerical aperture is enhanced to 1.9.The demonstration of mode conversion and beam steering with efficiency over 80%and a tilting range of 7.2°holds the potential for highly dense on-chip photonic systems for optical communication,optical sensing,nonlinear optics,and neural networks for deep learning.展开更多
Metamaterials have proven their ability to possess extraordinary physical properties distinct from naturally available materials,leading to exciting sensing functionalities and applications.However,metamaterial-based ...Metamaterials have proven their ability to possess extraordinary physical properties distinct from naturally available materials,leading to exciting sensing functionalities and applications.However,metamaterial-based sensing applications suffer from severe performance limitations due to noise interference and design constraints.Here,we propose a dual-phase strategy that leverages loss-induced different Fano-resonant phases to access both destructive and constructive signals of molecular vibration.When the two reverse signals are innovatively combined,the noise in the detection system is effectively suppressed,thereby breaking through the noise-related limitations.Additionally,by utilizing loss optimization of the plasmon-molecule coupling system,our dual-phase strategy enhances the efficiency of infrared energy transfer into the molecule without any additional fabrication complex,thereby overcoming the trade-off dilemma between performance and fabrication cost.Thanks to the pioneering breakthroughs in the limitations,our dual-phase strategy possesses an overwhelming competitive advantage in ultrasensitive vibrational spectroscopy over traditional metamaterial technology,including strong signal strength(×4),high sensitivity(×4.2),effective noise suppression(30%),low detection limit(13 ppm),and excellent selectivity among CO_(2),NH_(3),and CH_(4) mixtures.This work not only opens the door to various emerging ultrasensitive detection applications,including ultrasensitive in-breath diagnostics and high-information analysis of molecular information in dynamic reactions,but also gains new insights into the plasmon-molecule interactions in advanced metamaterials.展开更多
Ion mobility analysis is a well-known analytical technique for identifying gas-phase compounds in fastresponse gas-monitoring systems.However,the conventional plasma discharge system is bulky,operates at a high temper...Ion mobility analysis is a well-known analytical technique for identifying gas-phase compounds in fastresponse gas-monitoring systems.However,the conventional plasma discharge system is bulky,operates at a high temperature,and inappropriate for volatile organic compounds(VOCs)concentration detection.Therefore,we report a machine learning(ML)-enhanced ion mobility analyzer with a triboelectric-based ionizer,which offers good ion mobility selectivity and VOC recognition ability with a small-sized device and non-strict operating environment.Based on the charge accumulation mechanism,a multi-switched manipulation triboelectric nanogenerator(SM-TENG)can provide a direct current(DC)bias at the order of a few hundred,which can be further leveraged as the power source to obtain a unique and repeatable discharge characteristic of different VOCs,and their mixtures,with a special tip-plate electrode configuration.Aiming to tackle the grand challenge in the detection of multiple VOCs,the ML-enhanced ion mobility analysis method was successfully demonstrated by extracting specific features automatically from ion mobility spectrometry data with ML algorithms,which significantly enhance the detection ability of the SM-TENG based VOC analyzer,showing a portable real-time VOC monitoring solution with rapid response and low power consumption for future internet of things based environmental monitoring applications.展开更多
Thin-film PMUTs have been important research topics among microultrasound experts,and a concise review on their research progress is reported herein.Through rigorous surveying,scrutinization,and perception,it has been...Thin-film PMUTs have been important research topics among microultrasound experts,and a concise review on their research progress is reported herein.Through rigorous surveying,scrutinization,and perception,it has been determined that the work in this field began nearly 44 years ago with the primitive development of functional piezoelectric thin-film materials.To date,there are three major companies commercializing thin-film PMUTs on a bulk scale.This commercialization illustrates the extensive contributions made by more than 70 different centers,research institutes,and agencies across 4 different continents regarding the vast development of these devices’design,manufacturing,and function.This review covers these important contributions in a short yet comprehensive manner;in particular,this paper educates readers about the global PMUT outlook,their governing design principles,their manufacturing methods,nonconventional yet useful PMUT designs,and category-wise applications.Crucial comparison charts of thin-film piezoelectric material used in PMUTs,and their categorically targeted applications are depicted and discussed to enlighten any MEMS designer who plans to work with PMUTs.Moreover,each relevant section features clear future predictions based on the author’s past knowledge and expertise in this field of research and on the findings of a careful literature survey.In short,this review is a one-stop time-efficient guide for anyone interested in learning about these small devices.展开更多
In 2012,the first triboelectric nanogenerator(TENG)was invented to convert mechanical energy into electricity via the coupling effects of triboelectrification and electrostatic induction.1 Since then,extensive efforts...In 2012,the first triboelectric nanogenerator(TENG)was invented to convert mechanical energy into electricity via the coupling effects of triboelectrification and electrostatic induction.1 Since then,extensive efforts have been devoted into increasing the output power density of these energy harvesters,and the milestones have been summarized in Figure 1a with a maximum power density of 10MW/m2.2 Among the exciting achievements in TENG field,the liquid–solidbased TENGs(L–S TENG)are paving their ways for harvesting water energy from oceans,raindrops.展开更多
基金supported by A*STAR under the“Nanosystems at the Edge”program(Grant No.A18A4b0055)Ministry of Education(MOE)under the research grant of R-263-000-F18-112/A-0009520-01-00+1 种基金National Research Foundation Singapore grant CRP28-2022-0038the Reimagine Re-search Scheme(RRSC)Project(Grant A-0009037-02-00&A0009037-03-00)at National University of Singapore.
文摘Plasmonic nanoantennas provide unique opportunities for precise control of light–matter coupling in surface-enhanced infrared absorption(SEIRA)spectroscopy,but most of the resonant systems realized so far suffer from the obstacles of low sensitivity,narrow bandwidth,and asymmetric Fano resonance perturbations.Here,we demonstrated an overcoupled resonator with a high plasmon-molecule coupling coefficient(μ)(OC-Hμresonator)by precisely controlling the radiation loss channel,the resonator-oscillator coupling channel,and the frequency detuning channel.We observed a strong dependence of the sensing performance on the coupling state,and demonstrated that OC-Hμresonator has excellent sensing properties of ultra-sensitive(7.25%nm^(−1)),ultra-broadband(3–10μm),and immune asymmetric Fano lineshapes.These characteristics represent a breakthrough in SEIRA technology and lay the foundation for specific recognition of biomolecules,trace detection,and protein secondary structure analysis using a single array(array size is 100×100μm^(2)).In addition,with the assistance of machine learning,mixture classification,concentration prediction and spectral reconstruction were achieved with the highest accuracy of 100%.Finally,we demonstrated the potential of OC-Hμresonator for SARS-CoV-2 detection.These findings will promote the wider application of SEIRA technology,while providing new ideas for other enhanced spectroscopy technologies,quantum photonics and studying light–matter interactions.
基金National Natural Science Foundation of China(62304129)The Hong Kong Polytechnic University(P0046236)。
文摘On-chip spectrometers with high compactness and portability enable new applications in scientific research and industrial development.Fourier transform(FT)spectrometers have the potential to realize a high signal-to-noise ratio.Here we propose and demonstrate a generalized design for high-performance on-chip FT spectrometers.The spectrometer is based on the dynamic in-plane reconfiguration of a waveguide coupler enabled by an integrated comb-drive actuator array.The electrostatic actuation intrinsically features ultra-low power consumption.The coupling gap is crucial to the spectral resolution.The in-plane reconfiguration surmounts the lithography accuracy limitation of the coupling gap,boosting the resolution to 0.2 nm for dual spectral spikes over a large bandwidth of 100 nm(1.5–1.6μm)within a compact footprint of 75μm×1000μm.Meanwhile,the in-plane tuning range can be large enough for arbitrary wavelengths to ensure the effectiveness of spectrum reconstruction.As a result,the proposed spectrometer can be easily transplanted to other operation bands by simply scaling the structural parameters.As a proof-of-concept,a mid-infrared spectrometer is further demonstrated with a dual-spike reconstruction resolution of 1.5 nm and a bandwidth of 300 nm(4–4.3μm).
基金supported by the Reimagine Research Scheme(RRSC)grant(“Scalable AI Phenome Platform towards Fast-Forward Plant Breeding(Sensor)”,Nos.A-0009037-02-00 and A-0009037-03-00)at NUS,Singaporethe Reimagine Research Scheme(RRSC)grant(“Under-utilised Potential of Micro-biomes(soil)in Sustainable Urban Agriculture”,No.A-0009454-01-00)at NUS,Singaporethe RIE advanced manufacturing and engineering(AME)programmatic grant(“Nanosystems at the Edge”,No.A18A4b0055)at NUS,Singapore.
文摘Wearable and flexible electronics are shaping our life with their unique advantages of light weight,good compliance,and desirable comfortability.With marching into the era of Internet of Things(IoT),numerous sensor nodes are distributed throughout networks to capture,process,and transmit diverse sensory information,which gives rise to the demand on self-powered sensors to reduce the power consumption.Meanwhile,the rapid development of artificial intelligence(AI)and fifth-generation(5G)technologies provides an opportunity to enable smart-decision making and instantaneous data transmission in IoT systems.Due to continuously increased sensor and dataset number,conventional computing based on von Neumann architecture cannot meet the needs of brain-like high-efficient sensing and computing applications anymore.Neuromorphic electronics,drawing inspiration from the human brain,provide an alternative approach for efficient and low-power-consumption information processing.Hence,this review presents the general technology roadmap of self-powered sensors with detail discussion on their diversified applications in healthcare,human machine interactions,smart homes,etc.Via leveraging AI and virtual reality/augmented reality(VR/AR)techniques,the development of single sensors to intelligent integrated systems is reviewed in terms of step-by-step system integration and algorithm improvement.In order to realize efficient sensing and computing,brain-inspired neuromorphic electronics are next briefly discussed.Last,it concludes and highlights both challenges and opportunities from the aspects of materials,minimization,integration,multimodal information fusion,and artificial sensory system.
基金This work is supported by the RIE Advanced Manufacturing and Engineering(AME)Programmatic Grant Project(Grant A18A5b0056,WBS:A-0005117-02-00)the Advanced Research and Technology Innovation Centre(ARTIC)Project(WBS:A-0005947-20-00)the Ministry of Education(MOE)of Singapore Tier 1 Project(WBS:A-0005138-01-00).
文摘Metal-organic frameworks(MOFs)have been extensively used for gas sorption,storage and separation owing to ultrahigh porosity,exceptional thermal stability,and wide structural diversity.However,when it comes to ultra-low concentration gas detection,technical bottlenecks of MOFs appear due to the poor adsorption capacity at ppm-/ppblevel concentration and the limited sensitivity for signal transduction.Here,we present hybrid MOF-polymer physi-chemisorption mechanisms integrated with infrared(IR)nanoantennas for highly selective and ultrasensitive CO_(2) detection.To improve the adsorption capacity for trace amounts of gas molecules,MOFs are decorated with amino groups to introduce the chemisorption while maintaining the structural integrity for physisorption.Additionally,leveraging all major optimization methods,a multi-hotspot strategy is proposed to improve the sensitivity of nanoantennas by enhancing the near field and engineering the radiative and absorptive loss.As a benefit,we demonstrate the competitive advantages of our strategy against the state-of-the-art miniaturized IR CO_(2) sensors,including low detection limit,high sensitivity(0.18%/ppm),excellent reversibility(variation within 2%),and high selectivity(against C_(2)H_(5)OH,CH_(3)OH,N_(2)).This work provides valuable insights into the integration of advanced porous materials and nanophotonic devices,which can be further adopted in ultra-low concentration gas monitoring in industry and environmental applications.
基金The work was supported by the National Natural Science Foundation of China(Nos.51879022,51979045,52101400,52101382,and 52101345)China Scholarship Council(CSC No.202006570022)+2 种基金the Fundamental Research Funds for the Central Universities,China(Nos.3132019330,3132021340)Science and Technology Innovation Foundation of Dalian(No.2021JJ12GX028)Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(No.311021013).
文摘Wind energy is a promising renewable energy source for a low-carbon society.This study is to develop a fully packaged vortexinduced vibration triboelectric nanogenerator(VIV-TENG)for scavenging wind energy.The VIV-TENG consists of a wind vane,internal power generation unit,an external frame,four springs,a square cylinder and a circular turntable.The internal power generation unit consists of polytetrafluoroethylene(PTFE)balls,a honeycomb frame and two copper electrodes.Different from most of the previous wind energy harvesting TENGs,the bouncing PTFE balls are fully packaged in the square cylinder.The distinct design separates the process of contact electrification from the external environment,and at the same time avoids the frictional wear of the ordinary wind energy harvesting TENGs.The corresponding VIV parameters are investigated to evaluate their influence on the vibration behaviors and the energy output.Resonant state of the VIV-TENG corresponds to the high output performance from the VIV-TENG.The distinct,robust structure ensures the full-packaged VIV-TENG can harvest wind energy from arbitrary directions and even in undesirable weather conditions.The study proposes a novel TENG configuration for harvesting wind energy and the VIV-TENG proves promising powering micro-electro-mechanical appliances.
基金supported by the National Research Foundation(NRF)Singapore,under its AI Singapore Programme(AISG Award No.AISG-GC-2019-002)+1 种基金RIE advanced manufacturing and engineering(AME)programmatic grant(“Nanosystems at the Edge,”A18A4b0055)NUS iHealthtech Grant:Smart Sensors and Artificial Intelligence(AI)for Health(“Intelligent Monitoring System Based on Smart Wearable Sensors and Artificial Technology for the Treatment of Adolescent Idiopathic Scoliosis,”R-263-501-017-133).
文摘In the past few years,triboelectric nanogenerator-based(TENG-based)hybrid generators and systems have experienced a widespread and flourishing development,ranging among almost every aspect of our lives,e.g.,from industry to consumer,outdoor to indoor,and wearable to implantable applications.Although TENG technology has been extensively investigated for mechanical energy harvesting,most developed TENGs still have limitations of small output current,unstable power generation,and low energy utilization rate of multisource energies.To harvest the ubiquitous/coexisted energy forms including mechanical,thermal,and solar energy simultaneously,a promising direction is to integrate TENG with other transducing mechanisms,e.g.,electromagnetic generator,piezoelectric nanogenerator,pyroelectric nanogenerator,thermoelectric generator,and solar cell,forming the hybrid generator for synergetic single-source and multisource energy harvesting.The resultant TENG-based hybrid generators utilizing integrated transducing mechanisms are able to compensate for the shortcomings of each mechanism and overcome the above limitations,toward achieving a maximum,reliable,and stable output generation.Hence,in this review,we systematically introduce the key technologies of the TENG-based hybrid generators and hybridized systems,in the aspects of operation principles,structure designs,optimization strategies,power management,and system integration.The recent progress of TENG-based hybrid generators and hybridized systems for the outdoor,indoor,wearable,and implantable applications is also provided.Lastly,we discuss our perspectives on the future development trend of hybrid generators and hybridized systems in environmental monitoring,human activity sensation,human-machine interaction,smart home,healthcare,wearables,implants,robotics,Internet of things(IoT),and many other fields.
基金This work is supported by The Collaborative Research Project under the SIMTech-NUS Joint Laboratory,“SIMTech-NUS Joint Lab on Large-area Flexible Hybrid Electronics”and The National Key Research and Devel-opment Program of China(Grant No.2019YFB2004800,Project No.R-2020-S-002).
文摘In metaverse,a digital-twin smart home is a vital platform for immersive communication between the physical and virtual world.Triboelectric nanogenerators(TENGs)sensors contribute substantially to providing smart-home monitoring.However,TENG deployment is hindered by its unstable out-put under environment changes.Herein,we develop a digital-twin smart home using a robust all-TENG based information mat(InfoMat),which consists of an in-home mat array and an entry mat.The interdigital electrodes design allows environment-insensitive ratiometric readout from the mat array to can-cel the commonly experienced environmental variations.Arbitrary position sensing is also achieved because of the interval arrangement of the mat pixels.Concurrently,the two-channel entry mat generates multi-modality informa-tion to aid the 10-user identification accuracy to increase from 93% to 99% compared to the one-channel case.Furthermore,a digital-twin smart home is visualized by real-time projecting the information in smart home to virtual reality,including access authorization,position,walking trajectory,dynamic activities/sports,and so on.
基金supported by Youth Innovation Promotion Association CAS (2023175)the National Natural Science Foundation of China (T2125003)the Fundamental Research Funds for the Central Universities。
文摘The Schottky contact which is a crucial interface between semiconductors and metals is becoming increasingly significant in nano-semiconductor devices. A Schottky barrier, also known as the energy barrier, controls the depletion width and carrier transport across the metal–semiconductor interface.Controlling or adjusting Schottky barrier height(SBH) has always been a vital issue in the successful operation of any semiconductor device. This review provides a comprehensive overview of the static and dynamic adjustment methods of SBH, with a particular focus on the recent advancements in nanosemiconductor devices. These methods encompass the work function of the metals, interface gap states,surface modification, image-lowering effect, external electric field, light illumination, and piezotronic effect. We also discuss strategies to overcome the Fermi-level pinning effect caused by interface gap states, including van der Waals contact and 1D edge metal contact. Finally, this review concludes with future perspectives in this field.
基金Funding information Agency for Science,Technology and Research(A*STAR),Grant/Award Number:A18A5b0056Reimagine Research Scheme(RRSC),Grant/Award Numbers:A-0009037-02-00,A0009037-03-00,A-0009454-01-00+1 种基金Advanced Research and Technology Innovation Centre(ARTIC),Grant/Award Number:A-0005947-20-00Ministry of Education(MOE),Grant/Award Number:A-0009520-01-00。
文摘Water droplets help life in nature survive,thrive,and evolve.With water droplet serv-ing as one of the indispensable elements in the Internet of Things(IoT),many droplet-oriented technologies,such as microfluidics,droplet manipulation,electrowetting,and energy harvesting,make rapid progress driven by material science,computer science,and medicine.Droplet-based wearable devices are endowed with advantages such as flexibility,sensing ability,and automation for various parameter detection.Besides,the continuous exploration of droplet manipulation has led to the emergence of a wide variety of manipulation methods.Meanwhile,electrowetting that utilizes exter-nal fields modifying liquid–solid surfaces has found its applications in various areas,including droplet transportation,microfabrication,and healthcare.The energy gener-ation from water droplets also presents exciting opportunities for the development of novel electricity generators.These approaches for droplet utilization underscore the immense potentials and versatilities of droplet-based technologies in the IoT land-scape.Hence,this mini review presents the fundamental droplet-based technologies by summarizing their working mechanisms and methods,device structures,and appli-cations.Given the challenges in materials,fabrication,and system integration,this review shows the overall development roadmap in terms of improved functionality and performance and highlights the opportunities toward multifunctional,self-sustainable,and intelligent systems,which is called for IoT construction.
基金Agency for Science,Technology and Research,Grant/Award Number:A18A4b0055R-263-000-C91-305+2 种基金National Research Foundation Singapore,Grant/Award Number:AISG-GC-2019-002NRF-CRP15-2015-02National University of Singapore,Grant/Award Number:HIFES Seed Funding-2017-01。
文摘The past few years have witnessed the significant impacts of wearable electronics/photonics on various aspects of our daily life,for example,healthcare monitoring and treatment,ambient monitoring,soft robotics,prosthetics,flexible display,communication,human-machine interactions,and so on.According to the development in recent years,the next-generation wearable electronics and photonics are advancing rapidly toward the era of artificial intelligence(AI)and internet of things(IoT),to achieve a higher level of comfort,convenience,connection,and intelligence.Herein,this review provides an opportune overview of the recent progress in wearable electronics,photonics,and systems,in terms of emerging materials,transducing mechanisms,structural configurations,applications,and their further integration with other technologies.First,development of general wearable electronics and photonics is summarized for the applications of physical sensing,chemical sensing,humanmachine interaction,display,communication,and so on.Then self-sustainable wearable electronics/photonics and systems are discussed based on system integration with energy harvesting and storage technologies.Next,technology fusion of wearable systems and AI is reviewed,showing the emergence and rapid development of intelligent/smart systems.In the last section of this review,perspectives about the future development trends of the next-generation wearable electronics/photonics are provided,that is,toward multifunctional,self-sustainable,and intelligent wearable systems in the AI/IoT era.
基金This work was supported by grants from the National Research Foundation(NRF)CRP project‘Peripheral Nerve Prostheses:A Paradigm Shift in Restoring Dexterous Limb Function’(NRF-CRP10-2012-01,R-719-000-001-281)the NRF CRP project‘Self-Powered Body Sensor Network for Disease Management and Prevention Oriented Healthcare’(NRF-CRP8-2011-01,R-263-000-A27-281).
文摘The neural interface is a key component in wireless brain–computer prostheses.In this study,we demonstrate that a unique three-dimensional(3D)microneedle electrode on a flexible mesh substrate,which can be fabricated without complicated micromachining techniques,is conformal to the tissues with minimal invasiveness.Furthermore,we demonstrate that it can be applied to different functional layers in the nervous system without length limitation.The microneedle electrode is fabricated using drawing lithography technology from biocompatible materials.In this approach,the profile of a 3D microneedle electrode array is determined by the design of a two-dimensional(2D)pattern on the mask,which can be used to access different functional layers in different locations of the brain.Due to the sufficient stiffness of the electrode and the excellent flexibility of the mesh substrate,the electrode can penetrate into the tissue with its bottom layer fully conformal to the curved brain surface.Then,the exposed contact at the end of the microneedle electrode can successfully acquire neural signals from the brain.
基金This work was partly supported the National Key Research and Development Program of China(No.2019YFB2004800,Project No.R-2020-S-002)at NUSRI,Suzhou,ChinaSingapore-Poland Joint Grant(R-263-000-C91-305)“Chip-Scale MEMS MicroSpectrometer for Monitoring Harsh Industrial Gases”by Agency for Science,Technology and Research(A*STAR),Singapore and NAWA“Academic International Partnerships of Wroclaw University of Science and Technology”programmed by Polish National Agency for Academic Exchange Programme.
文摘For human beings of different ages and physical abilities, the inherent balance control system is ubiquitous and active to prevent falling, especially in motion states. A hybridized electromagnetic-triboelectric nanogenerator (HETNG) is prepared to harvest biomechanical energy during human balance control processes and achieve significant monitoring functions. The HETNG is composed of a symmetrical pendulum structure and a cylinder magnet rolling inside. Four coils are divided into two groups which form into two electromagnetic generators (EMGs). Besides, two spatial electrodes attached to the inner wall constitute a freestanding mode triboelectric nanogenerator (TENG). With a rectification circuit, the HETNG presents a high output power with a peak value of 0.55 W at a load of 160 Ω. Along with human balance control processes during walking, the HETNG can harvest biomechanical energy at different positions on the trunk. Moreover, the HETNG applied in artificial limb has been preliminarily simulated with the positions on thigh and foot, for monitoring the actions of squat and stand up, and lifting the leg up and down. For the elder that walks slowly with a walking aid, the HETNG equipped on the walking aid can help to record the motions of forwarding and unexpected falling, which is useful for calling for help. This work shows the potential of biomechanical energy-driven HETNG for powering portable electronics and monitoring human motions, also shows significant concerns to people lacked action capability or disabled.
基金Advanced Research and Technology Innovation CentreA*STAR,Grant/Award Number:A18A5b0056+1 种基金National Research Foundation-Singapore,Grant/Award Numbers:NRF-CRP15-2015-02,RIE2020-AME-2019National University of Singapore,Grant/Award Number:R261-518-009-720。
文摘Photonic integrated circuits(PICs)provide a promising platform for miniaturized on-chip optical systems for communication,computation,and sensing applications.The dense integration of photonic components is one of the keys to exploit the advantages of PIC.Although light focusing is a fundamental and indispensable function in PICs,focusing light at the micro/nanometer-scale is challenging.Here,a bigradient on-chip metalens(BOML)is proposed to achieve ultrasmall focal lengths and spot sizes at the subwavelength scale for dense PICs.The design of BOML combines gradient geometry and gradient refractive index into one metalens by simultaneously engineering the length and width of subwavelength silicon slots.With a small device footprint of only 168μm,the BOML achieves efficient on-chip focusing with the recordbreaking figure-of-merits,which are the ratio of wavelength to focal length/spot size(0.268 and 2.83)and numerical aperture(1.78).Leveraging on the Fresnel design,the footprint of BOML is further reduced by 55.1%,and the numerical aperture is enhanced to 1.9.The demonstration of mode conversion and beam steering with efficiency over 80%and a tilting range of 7.2°holds the potential for highly dense on-chip photonic systems for optical communication,optical sensing,nonlinear optics,and neural networks for deep learning.
基金National Key Research and Development Program of China,Grant/Award Number:2019YFB2004800Advanced Research and Technology Innovation Center(ARTIC)Project,Grant/Award Number:A-0005947-20-00+2 种基金National Natural Science Foundation of China,Grant/Award Number:52072041Ministry of Education(MOE)of Singapore Tier 1 grants,Grant/Award Number:A-0005138-01-00China Postdoctoral Science Foundation,Grant/Award Number:2021M693746。
文摘Metamaterials have proven their ability to possess extraordinary physical properties distinct from naturally available materials,leading to exciting sensing functionalities and applications.However,metamaterial-based sensing applications suffer from severe performance limitations due to noise interference and design constraints.Here,we propose a dual-phase strategy that leverages loss-induced different Fano-resonant phases to access both destructive and constructive signals of molecular vibration.When the two reverse signals are innovatively combined,the noise in the detection system is effectively suppressed,thereby breaking through the noise-related limitations.Additionally,by utilizing loss optimization of the plasmon-molecule coupling system,our dual-phase strategy enhances the efficiency of infrared energy transfer into the molecule without any additional fabrication complex,thereby overcoming the trade-off dilemma between performance and fabrication cost.Thanks to the pioneering breakthroughs in the limitations,our dual-phase strategy possesses an overwhelming competitive advantage in ultrasensitive vibrational spectroscopy over traditional metamaterial technology,including strong signal strength(×4),high sensitivity(×4.2),effective noise suppression(30%),low detection limit(13 ppm),and excellent selectivity among CO_(2),NH_(3),and CH_(4) mixtures.This work not only opens the door to various emerging ultrasensitive detection applications,including ultrasensitive in-breath diagnostics and high-information analysis of molecular information in dynamic reactions,but also gains new insights into the plasmon-molecule interactions in advanced metamaterials.
基金supported by the research grant of‘‘Chip-Scale MEMS Micro-Spectrometer for Monitoring Harsh Industrial Gases”(R-263-000-C91-305)at the National University of Singapore(NUS),Singaporethe research grant of RIE Advanced Manufacturing and Engineering(AME)programmatic grant A18A4b0055‘‘Nanosystems at the Edge”at NUS,Singapore。
文摘Ion mobility analysis is a well-known analytical technique for identifying gas-phase compounds in fastresponse gas-monitoring systems.However,the conventional plasma discharge system is bulky,operates at a high temperature,and inappropriate for volatile organic compounds(VOCs)concentration detection.Therefore,we report a machine learning(ML)-enhanced ion mobility analyzer with a triboelectric-based ionizer,which offers good ion mobility selectivity and VOC recognition ability with a small-sized device and non-strict operating environment.Based on the charge accumulation mechanism,a multi-switched manipulation triboelectric nanogenerator(SM-TENG)can provide a direct current(DC)bias at the order of a few hundred,which can be further leveraged as the power source to obtain a unique and repeatable discharge characteristic of different VOCs,and their mixtures,with a special tip-plate electrode configuration.Aiming to tackle the grand challenge in the detection of multiple VOCs,the ML-enhanced ion mobility analysis method was successfully demonstrated by extracting specific features automatically from ion mobility spectrometry data with ML algorithms,which significantly enhance the detection ability of the SM-TENG based VOC analyzer,showing a portable real-time VOC monitoring solution with rapid response and low power consumption for future internet of things based environmental monitoring applications.
基金This research is supported by A*STAR under the“Nanosystems at the Edge”program(Grant No.A18A4b0055)by Reimagine Research Scheme(RRSC)under the“Under-utilized Potential of Microbiomes(soil)in Sustainable Urban Agriculture”program(Grant No.A-0009454-01-00)“Scalable AI Phenome Platform towards Fast-Forward Plant Breeding(Sensor)”program(Grant No.A-0009037-03-00(25%)A-0009037-02-00(75%)).
文摘Thin-film PMUTs have been important research topics among microultrasound experts,and a concise review on their research progress is reported herein.Through rigorous surveying,scrutinization,and perception,it has been determined that the work in this field began nearly 44 years ago with the primitive development of functional piezoelectric thin-film materials.To date,there are three major companies commercializing thin-film PMUTs on a bulk scale.This commercialization illustrates the extensive contributions made by more than 70 different centers,research institutes,and agencies across 4 different continents regarding the vast development of these devices’design,manufacturing,and function.This review covers these important contributions in a short yet comprehensive manner;in particular,this paper educates readers about the global PMUT outlook,their governing design principles,their manufacturing methods,nonconventional yet useful PMUT designs,and category-wise applications.Crucial comparison charts of thin-film piezoelectric material used in PMUTs,and their categorically targeted applications are depicted and discussed to enlighten any MEMS designer who plans to work with PMUTs.Moreover,each relevant section features clear future predictions based on the author’s past knowledge and expertise in this field of research and on the findings of a careful literature survey.In short,this review is a one-stop time-efficient guide for anyone interested in learning about these small devices.
基金Reimagine Research Scheme(RRSC),Grant/Award Number:WBS:A‐0009454‐01‐00Reimagine Research Scheme(RRSC),Grant/Award Number:WBS:A‐0009037‐03‐00。
文摘In 2012,the first triboelectric nanogenerator(TENG)was invented to convert mechanical energy into electricity via the coupling effects of triboelectrification and electrostatic induction.1 Since then,extensive efforts have been devoted into increasing the output power density of these energy harvesters,and the milestones have been summarized in Figure 1a with a maximum power density of 10MW/m2.2 Among the exciting achievements in TENG field,the liquid–solidbased TENGs(L–S TENG)are paving their ways for harvesting water energy from oceans,raindrops.
