The rapid advancement of modern electronics has led to a surge in solid electronic waste,which poses significant environmental and health challenges.This review focuses on recent developments in paper-based electronic...The rapid advancement of modern electronics has led to a surge in solid electronic waste,which poses significant environmental and health challenges.This review focuses on recent developments in paper-based electronic devices fabricated through low-cost,hand-printing techniques,with particular emphasis on their applications in energy harvesting,storage,and sensing.Unlike conventional plastic-based substrates,cellulose paper offers several advantages,including biodegradability,recyclability,and low fabrication cost.By integrating functional nanomaterials such as two-dimensional chalcogenides,metal oxides,conductive polymers,and carbon-based structures onto paper,researchers have achieved high-performance devices such as broadband photodetectors(responsivity up to 52 mA/W),supercapacitors(energy density~15.1 mWh/cm^(2)),and pressure sensors(sensitivity~18.42 kPa^(-1)).The hand-printing approach,which eliminates the need for sophisticated equipment and toxic solvents,offers a promising route for scalable,sustainable,and disposable electronics.This review outlines fabrication methods and key performance metrics,and discusses the current challenges and future directions for realizing robust,flexible devices aligned with green technology and the United Nation’s Sustainable Development Goals.展开更多
Flexible electronics and optoelectronics exhibit inevitable trends in next-generation intelligent industries,including healthcare and wellness,electronic skins,the automotive industry,and foldable or rollable displays...Flexible electronics and optoelectronics exhibit inevitable trends in next-generation intelligent industries,including healthcare and wellness,electronic skins,the automotive industry,and foldable or rollable displays.Traditional bulk-material-based flexible devices considerably rely on lattice-matched crystal structures and are usually plagued by unavoidable chemical disorders at the interface.Two-dimensional van der Waals materials(2D VdWMs)have exceptional multifunctional properties,including large specific area,dangling-bond-free interface,plane-to-plane van der Waals interactions,and excellent mechanical,electrical,and optical properties.Thus,2D VdWMs have considerable application potential in functional intelligent flexible devices.To utilize the unique properties of 2D VdWMs and their van der Waals heterostructures,new designs and configurations of electronics and optoelectronics have emerged.However,these new designs and configurations do not consider lattice mismatch and process incompatibility issues.In this review,we summarized the recently reported 2D VdWM-based flexible electronic and optoelectronic devices with various functions thoroughly.Moreover,we identified the challenges and opportunities for further applications of 2D VdWM-based flexible electronics and optoelectronics.展开更多
Flexible electronics technology is considered as a revolutionary technology to unlock the bottleneck of traditional rigid electronics that prevalent for decades,thereby fueling the next-generation electronics.In the p...Flexible electronics technology is considered as a revolutionary technology to unlock the bottleneck of traditional rigid electronics that prevalent for decades,thereby fueling the next-generation electronics.In the past few decades,the research on flexible electronic devices based on organic materials has witnessed rapid development and substantial achievements,and inorganic semiconductors are also now beginning to shine in the field of flexible electronics.As validated by the latest research,some of the inorganic semiconductors,particularly those at low dimension,unexpectedly exhibited excellent mechanical flexibility on top of superior electrical properties.Herein,we bring together a comprehensive analysis on the recently burgeoning low-dimension inorganic semiconductor materials in flexible electronics,including one-dimensional(1D)inorganic semiconductor nanowires(NWs)and two-dimensional(2D)transition metal dichalcogenides(TMDs).The fundamental electrical properties,optical properties,mechanical properties and strain engineering of materials,and their performance in flexible device applications are discussed in detail.We also propose current challenges and predict future development directions including material synthesis and device fabrication and integration.展开更多
The conventional analytical method of predicting strain in a thin film under bending is restricted to the uniform material assumption, while in flexible electronics, the film/substrate structure is widely used with mi...The conventional analytical method of predicting strain in a thin film under bending is restricted to the uniform material assumption, while in flexible electronics, the film/substrate structure is widely used with mismatched material properties taken into account. In this paper,a piecewise model is proposed to analyze the axial strain in a thin film of flexible electronics with the shear modification factor and principle of virtual work. The excellent agreement between analytical prediction and finite element results indicates that the model is capable of predicting the strain of the film/substrate structure in flexible electronics, whose mechanical stability and electrical performance is dependent on the strain state in the thin film.展开更多
Flexible electronics offer a multitude of advantages,such as flexibility,lightweight property,portability,and high durability.These unique properties allow for seamless applications to curved and soft surfaces,leading...Flexible electronics offer a multitude of advantages,such as flexibility,lightweight property,portability,and high durability.These unique properties allow for seamless applications to curved and soft surfaces,leading to extensive utilization across a wide range of fields in consumer electronics.These applications,for example,span integrated circuits,solar cells,batteries,wearable devices,bio-implants,soft robotics,and biomimetic applications.Recently,flexible electronic devices have been developed using a variety of materials such as organic,carbon-based,and inorganic semiconducting materials.Silicon(Si)owing to its mature fabrication process,excellent electrical,optical,thermal properties,and cost efficiency,remains a compelling material choice for flexible electronics.Consequently,the research on ultra-thin Si in the context of flexible electronics is studied rigorously nowadays.The thinning of Si is crucially important for flexible electronics as it reduces its bending stiffness and the resultant bending strain,thereby enhancing flexibility while preserving its exceptional properties.This review provides a comprehensive overview of the recent efforts in the fabrication techniques for forming ultra-thin Si using top-down and bottom-up approaches and explores their utilization in flexible electronics and their applications.展开更多
The burgeoning interest in flexible electronics necessitates the creation of patterning technology specifically tailored for flexible substrates and complex surface morphologies.Among a variety of patterning technique...The burgeoning interest in flexible electronics necessitates the creation of patterning technology specifically tailored for flexible substrates and complex surface morphologies.Among a variety of patterning techniques,transfer printing emerges as one of the most efficient,cost-effective,and scalable methods.It boasts the ability for high-throughput fabrication of 0–3D micro-and nano-structures on flexible substrates,working in tandem with traditional lithography methods.This review highlights the critical issue of transfer printing:the flawless transfer of devices during the pick-up and printing process.We encapsulate recent advancements in numerous transfer printing techniques,with a particular emphasis on strategies to control adhesion forces at the substrate/device/stamp interfaces.These strategies are employed to meet the requirements of competing fractures for successful pick-up and print processes.The mechanism,advantages,disadvantages,and typical applications of each transfer printing technique will be thoroughly discussed.The conclusion section provides design guidelines and probes potential directions for future advancements.展开更多
As a potential flexible substrate for flexible electronics, a polymer-sandwiched ultra-thin silicon platform is stud- ied. SU-8 photoresist coated on the silicon membrane improves its flexibility as shown by an ANSYS ...As a potential flexible substrate for flexible electronics, a polymer-sandwiched ultra-thin silicon platform is stud- ied. SU-8 photoresist coated on the silicon membrane improves its flexibility as shown by an ANSYS simulation. Using the plasma enhanced chemical vapor deposited Si02/Si3N4 composite film as an etching mask, a 4＂ silicon- （100） wafer is thinned to 26[tm without rupture in a 30wt.% KOH solution. The thinned wafer is coated on both sides with 20 pm of SU-8 photoresist and is cut into strips. Then the strips are bent by a caliper to measure its bending radius. A sector model of bending deformation is adopted to estimate the radius of curvature. The determined minimal bending radius of the polymer-sandwiched ultra-thin silicon layer is no more than 3.3mm. The fabrication process of this sandwich structure can be used as a post-fabrication process for high performance flexible electronics.展开更多
Laminated hard-soft integrated structures play a significant role in the fabrication and development of flexible electronics devices. Flexible electronics have advantageous characteristics such as soft and light-weigh...Laminated hard-soft integrated structures play a significant role in the fabrication and development of flexible electronics devices. Flexible electronics have advantageous characteristics such as soft and light-weight, can be folded,twisted, flipped inside-out, or be pasted onto other surfaces of arbitrary shapes. In this paper, an analytical model is presented to study the mechanics of laminated hard-soft structures in flexible electronics under a stickup state. Thirdorder polynomials are used to describe the displacement field,and the principle of virtual work is adopted to derive the governing equations and boundary conditions. The normal strain and the shear stress along the thickness direction in the bimaterial region are obtained analytically, which agree well with the results from finite element analysis. The analytical model can be used to analyze stickup state laminated structures, and can serve as a valuable reference for the failure prediction and optimal design of flexible electronics in the future.展开更多
This study employs theoretical analysis to explore the application prospects of flexible electronics technology in wearable devices. The research first reviews the development history and theoretical foundations of fl...This study employs theoretical analysis to explore the application prospects of flexible electronics technology in wearable devices. The research first reviews the development history and theoretical foundations of flexible electronics technology, including materials science, electronic engineering, and human-computer interaction theory. Through systematic analysis, the study evaluates the theoretical potential of flexible displays, flexible sensors, and flexible energy storage devices in wearable technology. The research finds that flexible electronics technology can significantly improve the comfort, functionality, and durability of wearable devices. Theoretical analysis indicates that flexible sensors have unique advantages in physiological monitoring and human-computer interaction, while flexible displays and batteries may revolutionize the form and usage patterns of wearable devices. However, the study also points out theoretical challenges faced by flexible electronics technology, such as material stability and feasibility of large-scale manufacturing. To address these challenges, the research proposes an interdisciplinary research framework, emphasizing the synergistic innovation of materials science, electronic engineering, and ergonomics. Finally, the study envisions the theoretical prospects of integrating flexible electronics with other emerging technologies, providing directions for future research.展开更多
Flexible electronics is an emerging technology,which breaks through the constraints of traditional rigid electronics,enabling electronic devices to adapt to various complex application scenarios.Meanwhile,a variety of...Flexible electronics is an emerging technology,which breaks through the constraints of traditional rigid electronics,enabling electronic devices to adapt to various complex application scenarios.Meanwhile,a variety of functions including sensing,actuation and energy harvesting,promote flexible electronics to be widely used in healthcare,robotics,Internet of Things,and so on.Micro/nanomanufacturing is the key technology to realize flexible electronics.Through micro/nanomanufacturing,various micro/nano-scale electronic components such as transistors and sensors can be precisely fabricated on flexible substrates,endowing flexible electronics with excellent performance.On the other hand,the development of flexible electronics also provides new challenges for micro/nanomanufacturing,due to the new flexible materials and device morphology.Currently,flexible electronics and micro/nanomanufacturing have attracted great at-tention from researchers around the world.Scientists explore new materials and techniques to further expand the applications of flexible electronics.On this basis,we have organized a special topic on“Flexible Electronics and Micro/Nanomanufacturing”in National Science Open(NSO)to discuss the development of flexible electronics.The topic focuses on key issues in the design and manufacturing of flexible electronics.We have invited nine scientists from different fields to present their latest research findings and prospective analyses of flexible electronics systematically.展开更多
The realization of natural and authentic facial expressions in humanoid robots poses a challenging and prominent research domain,encompassing interdisciplinary facets including mechanical design,sensing and actuation ...The realization of natural and authentic facial expressions in humanoid robots poses a challenging and prominent research domain,encompassing interdisciplinary facets including mechanical design,sensing and actuation control,psychology,cognitive science,flexible electronics,artificial intelligence(AI),etc.We have traced the recent developments of humanoid robot heads for facial expressions,discussed major challenges in embodied AI and flexible electronics for facial expression recognition and generation,and highlighted future trends in this field.Developing humanoid robot heads with natural and authentic facial expressions demands collaboration in interdisciplinary fields such as multi-modal sensing,emotional computing,and human-robot interactions(HRIs)to advance the emotional anthropomorphism of humanoid robots,bridging the gap between humanoid robots and human beings and enabling seamless HRIs.展开更多
The microfractals of leaf skeletons can be effective substrates for flexible electronics due to their high surface-to-volume ratio,transparency,breathability and flexibility.The challenge lies in replicating these fra...The microfractals of leaf skeletons can be effective substrates for flexible electronics due to their high surface-to-volume ratio,transparency,breathability and flexibility.The challenge lies in replicating these fractal surfaces at the microscale in a way that is scalable,freestanding,and integrable with various materials.In this study,we present a novel method for the biomimetic microfabrication of leafskeleton-based fractal surfaces.We utilized a modified electrospinning method,replacing the fiber collector with a metalized biotic collector to replicate the microstructures.The biomimetic microfractals demonstrated~90%replication accuracy,>80%transparency,good stretchability,and breathability,and were freestanding.The method is versatile,allowing for the use of a wide range of polymers in biomimetic microfabrication.For application in flexible electronics,biomimetic conductive fractal patterns(BCFP)were fabricated by immobilizing Ag Nanowires(AgNW)using a simple spraybased method.The BCFP exhibited high conductivity with sheet resistances<20Ωsq-1 while maintaining good transparencies.The BCFP adheres conformally to human skin,acting as an electronic skin(e-skin).To demonstrate the application,the BCFP was used to fabricate a tactile pressure sensor.In addition to their excellent transparency at low sheet resistances,stretchability,moisture resistance,and tight conformal bonding with the target surface,the BCFP also allows the evaporation of perspiration,making them suitable for long-term use as epidermal sensors.The application of BCFP in advanced bionic skin was demonstrated through gesture monitoring experiments.展开更多
Ionogels,with their combined properties of flexibility,excellent ionic conductivity,and biomechanical characteristics similar to biological tissues,have become key materials in flexible electronics,exhibiting enormous...Ionogels,with their combined properties of flexibility,excellent ionic conductivity,and biomechanical characteristics similar to biological tissues,have become key materials in flexible electronics,exhibiting enormous appli-cation potential in fields such as health monitoring and smart wearables.However,ionogels are susceptible to mechanical damage.Under large deformations and continuous mechan-ical loading,structural damage and device failure are in-evitable.Self-healing ability can significantly improve the reliability,service life,and safety of devices.This review dis-cusses the latest progress in self-healing ionogels,covering self-healing mechanisms,as well as the design,preparation,and applications of various ionogel-based flexible electronic devices,including wearable sensors,flexible triboelectric na-nogenerators,supercapacitors,flexible displays,and soft ro-bots.Furthermore,based on the self-healing mechanisms of ionogels and the design and manufacturing of related pro-ducts,we put forward perspectives on the development of flexible electronics.This review is expected to accelerate the development of self-healing ionogels in the applications of various flexible electronic devices.展开更多
The rapid expansion of the Internet of Things(IoT)and wearable technologies has driven the demand for flexible,lightweight,and multifunctional electronic devices.However,conventional rigid electronics often fall short...The rapid expansion of the Internet of Things(IoT)and wearable technologies has driven the demand for flexible,lightweight,and multifunctional electronic devices.However,conventional rigid electronics often fall short in meeting the requirements for conformability,comfort,and durability in applications such as health monitoring,soft robotics,and human-machine interfaces(HMIs)[1].While two-dimensional materials like graphene and transition metal dichalcogenides have been extensively explored,their limitations in electrical conductivity,tunable surface properties,and scalable synthesis have spurred the search for alternative materials[2].展开更多
Self-rectifying memristor(SRM)arrays hold tremendous potential in high-density data storage and energy efficient neuromorphic computing.However,SRM arrays are mostly developed on rigid substrates and lack mechanical f...Self-rectifying memristor(SRM)arrays hold tremendous potential in high-density data storage and energy efficient neuromorphic computing.However,SRM arrays are mostly developed on rigid substrates and lack mechanical flexibility,limiting their applications in intelligent electronic skin,wearable technologies,etc.Here,we present a high performance SRM array based on Pt/HfO_(2)/Ta_(2)O_(5−x)/Ti heterojunctions,which can be fabricated on a flexible polyimides(PI)substrate and demonstrates exceptional memristive performance under bending conditions(bending radius(R)=1 cm,rectifying ratio>10^(4),retention time>10^(4) s and endurance>105 cycles).We demonstrate a 16×16 flexible memristor array offering noise filtering and data storage capabilities,which can be used to accurately process and store the signals transmitted by a pressure sensor array.This research represents an important advancement towards the realization of next-generation high-performance flexible electronics.展开更多
Flexible electronics have emerged as a revolutionary paradigm to unlock novel possibilities across diverse fields such as wearables,healthcare,and wireless communications.Among the numerous materials,liquid metal(LM)t...Flexible electronics have emerged as a revolutionary paradigm to unlock novel possibilities across diverse fields such as wearables,healthcare,and wireless communications.Among the numerous materials,liquid metal(LM)thin films,characterized by high electrical conductivity,high thermal conductivity,high ductility,and biocompatibility,have become crucial materials for the fabrication of flexible electronics.Nevertheless,the current state-of-the-art technologies still face several challenges including complex preparation processes,poor compatibility with substrates,and insufficient mechanical stability.In this comprehensive review,the innovative preparation technologies for LM thin films including patterned printing methods,various coatings techniques,and interface-driven assembly approaches have been systematically summarized.The underlying design principle which involves modulating the ratio of composition materials and process conditions,are elucidated in detail.Moreover,their innovative applications in flexible electronics are concluded.Finally,we provide a forward-looking perspective on the future research and development trends in this burgeoning field.It aims to guide and inspire further scientific investigations and technological advancements.展开更多
In the past decade,the global industry and research attentions on intelligent skin-like electronics have boosted their applications in diverse fields including human healthcare,Internet of Things,human–machine interf...In the past decade,the global industry and research attentions on intelligent skin-like electronics have boosted their applications in diverse fields including human healthcare,Internet of Things,human–machine interfaces,artificial intelligence and soft robotics.Among them,flexible humidity sensors play a vital role in noncontact measurements relying on the unique property of rapid response to humidity change.This work presents an overview of recent advances in flexible humidity sensors using various active functional materials for contactless monitoring.Four categories of humidity sensors are highlighted based on resistive,capacitive,impedance-type and voltage-type working mechanisms.Furthermore,typical strategies including chemical doping,structural design and Joule heating are introduced to enhance the performance of humidity sensors.Drawing on the noncontact perception capability,human/plant healthcare management,human-machine interactions as well as integrated humidity sensor-based feedback systems are presented.The burgeoning innovations in this research field will benefit human society,especially during the COVID-19 epidemic,where cross-infection should be averted and contactless sensation is highly desired.展开更多
Flexible electronics have emerged as an exciting research area in recent years,serving as ideal interfaces bridging biological systems and conventional electronic devices.Flexible electronics can not only collect phys...Flexible electronics have emerged as an exciting research area in recent years,serving as ideal interfaces bridging biological systems and conventional electronic devices.Flexible electronics can not only collect physiological signals for human health monitoring but also enrich our daily life with multifunctional smart materials and devices.Conductive hydrogels(CHs)have become promising candidates for the fabrication of flexible electronics owing to their biocompatibility,adjustable mechanical flexibility,good conductivity,and multiple stimuli-responsive properties.To achieve on-demand mechanical properties such as stretchability,compressibility,and elasticity,the rational design of polymer networks via modulating chemical and physical intermolecular interactions is required.Moreover,the type of conductive components(eg,electron-conductive materials,ions)and the incorporation method also play an important role in the conductivity of CHs.Electron-CHs usually possess excellent conductivity,while ion-CHs are generally transparent and can generate ion gradients within the hydrogel matrices.This mini review focuses on the recent advances in the design of CHs,introducing various design strategies for electron-CHs and ion-CHs employed in flexible electronics and highlighting their versatile applications such as biosensors,batteries,supercapacitors,nanogenerators,actuators,touch panels,and displays.展开更多
Wearable electronics offer incredible benefits in mobile healthcare monitoring,sensing,portable energy harvesting and storage,human-machine interactions,etc.,due to the evolution of rigid electronics structure to flex...Wearable electronics offer incredible benefits in mobile healthcare monitoring,sensing,portable energy harvesting and storage,human-machine interactions,etc.,due to the evolution of rigid electronics structure to flexible and stretchable devices.Lately,transition metal carbides and nitrides(MXenes)are highly regarded as a group of thriving two-dimensional nanomaterials and extraordinary building blocks for emerging flexible electronics platforms because of their excellent electrical conductivity,enriched surface functionalities,and large surface area.This article reviews the most recent developments in MXene-enabled flexible electronics for wearable electronics.Several MXeneenabled electronic devices designed on a nanometric scale are highlighted by drawing attention to widely developed nonstructural attributes,including 3D configured devices,textile and planer substrates,bioinspired structures,and printed materials.Furthermore,the unique progress of these nanodevices is highlighted by representative applications in healthcare,energy,electromagnetic interference(EMI)shielding,and humanoid control of machines.The emerging prospects of MXene nanomaterials as a key frontier in nextgeneration wearable electronics are envisioned and the design challenges of these electronic systems are also discussed,followed by proposed solutions.展开更多
Recent breakthrough in eutectic gallium-indium alloy has revealed its great potential in modern electronic engineering. Here, we established a general method towards super-fast fabrication of flexible electronics via ...Recent breakthrough in eutectic gallium-indium alloy has revealed its great potential in modern electronic engineering. Here, we established a general method towards super-fast fabrication of flexible electronics via semi-liquid metal and adhesion-selection enabled rolling and transfer (SMART) printing on various substrates. Based on the semiliquid metal and its adhesion-difference on specifically designed target materials, we demonstrated that the rolling and transfer printing method could serve to rapidly manufacture a wide variety of complicated patterns with high resolution and large size. The process is much faster than most of the currently existing electronic fabrication strategies including liquid metal printing ever developed, and the cost either in time or consumption rate is rather low. As illustrated, a series of functional flexible and stretchable electronics such as multiple layer and large area circuits were fabricated to show their superior merit in combination with electrical conductivity and deformability. In addition, it was also demonstrated that the electronics fabricated in this way exhibited good repeatablity. A most noteworthy advantage is that all the fabrication processes could be highly automatic in the sense that user-friendly machines can thus be developed. This method paves a practical way for super-fast soft electronics manufacture and is expected to play an important role in the coming industry and consumer electronics.展开更多
基金The Consortium for Scientific Research,Indore(CSR,Indore)(No.CRS/2021-22/01/426)is acknowledged by the authorsFor the research facilities,the authors are grateful to CHARUSAT University.
文摘The rapid advancement of modern electronics has led to a surge in solid electronic waste,which poses significant environmental and health challenges.This review focuses on recent developments in paper-based electronic devices fabricated through low-cost,hand-printing techniques,with particular emphasis on their applications in energy harvesting,storage,and sensing.Unlike conventional plastic-based substrates,cellulose paper offers several advantages,including biodegradability,recyclability,and low fabrication cost.By integrating functional nanomaterials such as two-dimensional chalcogenides,metal oxides,conductive polymers,and carbon-based structures onto paper,researchers have achieved high-performance devices such as broadband photodetectors(responsivity up to 52 mA/W),supercapacitors(energy density~15.1 mWh/cm^(2)),and pressure sensors(sensitivity~18.42 kPa^(-1)).The hand-printing approach,which eliminates the need for sophisticated equipment and toxic solvents,offers a promising route for scalable,sustainable,and disposable electronics.This review outlines fabrication methods and key performance metrics,and discusses the current challenges and future directions for realizing robust,flexible devices aligned with green technology and the United Nation’s Sustainable Development Goals.
基金supported by the Natural Science Foundation of Beijing Municipality(No.Z180011)the National Natural Science Foundation of China(Nos.51991340,51991342,51972022,92163205,and 52188101)+2 种基金the National Key Research and Development Program of China(No.2016YFA0202701)the Fundamental Research Funds for the Central Universities(No.FRF-TP-19-025A3)the Overseas Expertise Introduction Projects for Discipline Innovation(No.B14003)。
文摘Flexible electronics and optoelectronics exhibit inevitable trends in next-generation intelligent industries,including healthcare and wellness,electronic skins,the automotive industry,and foldable or rollable displays.Traditional bulk-material-based flexible devices considerably rely on lattice-matched crystal structures and are usually plagued by unavoidable chemical disorders at the interface.Two-dimensional van der Waals materials(2D VdWMs)have exceptional multifunctional properties,including large specific area,dangling-bond-free interface,plane-to-plane van der Waals interactions,and excellent mechanical,electrical,and optical properties.Thus,2D VdWMs have considerable application potential in functional intelligent flexible devices.To utilize the unique properties of 2D VdWMs and their van der Waals heterostructures,new designs and configurations of electronics and optoelectronics have emerged.However,these new designs and configurations do not consider lattice mismatch and process incompatibility issues.In this review,we summarized the recently reported 2D VdWM-based flexible electronic and optoelectronic devices with various functions thoroughly.Moreover,we identified the challenges and opportunities for further applications of 2D VdWM-based flexible electronics and optoelectronics.
基金supported by the Natural Science Foundation of China(No.51902101)Natural Science Foundation of Jiangsu Province(No.BK20201381)+1 种基金Science Foundation of Nanjing University of Posts and Telecommunications(No.NY219144)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX22_0254).
文摘Flexible electronics technology is considered as a revolutionary technology to unlock the bottleneck of traditional rigid electronics that prevalent for decades,thereby fueling the next-generation electronics.In the past few decades,the research on flexible electronic devices based on organic materials has witnessed rapid development and substantial achievements,and inorganic semiconductors are also now beginning to shine in the field of flexible electronics.As validated by the latest research,some of the inorganic semiconductors,particularly those at low dimension,unexpectedly exhibited excellent mechanical flexibility on top of superior electrical properties.Herein,we bring together a comprehensive analysis on the recently burgeoning low-dimension inorganic semiconductor materials in flexible electronics,including one-dimensional(1D)inorganic semiconductor nanowires(NWs)and two-dimensional(2D)transition metal dichalcogenides(TMDs).The fundamental electrical properties,optical properties,mechanical properties and strain engineering of materials,and their performance in flexible device applications are discussed in detail.We also propose current challenges and predict future development directions including material synthesis and device fabrication and integration.
基金support from the National Natural Science Foundation of China(No.11172022)the support by the China Postdoctoral Science Foundation(No.2013M530907)the National Natural Science Foundation of China(No.11302039)
文摘The conventional analytical method of predicting strain in a thin film under bending is restricted to the uniform material assumption, while in flexible electronics, the film/substrate structure is widely used with mismatched material properties taken into account. In this paper,a piecewise model is proposed to analyze the axial strain in a thin film of flexible electronics with the shear modification factor and principle of virtual work. The excellent agreement between analytical prediction and finite element results indicates that the model is capable of predicting the strain of the film/substrate structure in flexible electronics, whose mechanical stability and electrical performance is dependent on the strain state in the thin film.
基金supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. RS-2024-00353768)the Yonsei Fellowship, funded by Lee Youn Jae. This study was funded by the KIST Institutional Program Project No. 2E31603-22-140 (K J Y). S M W acknowledges the support by National Research Foundation of Korea (NRF) grant funded by the Korea government (Grant Nos. NRF-2021R1C1C1009410, NRF2022R1A4A3032913 and RS-2024-00411904)
文摘Flexible electronics offer a multitude of advantages,such as flexibility,lightweight property,portability,and high durability.These unique properties allow for seamless applications to curved and soft surfaces,leading to extensive utilization across a wide range of fields in consumer electronics.These applications,for example,span integrated circuits,solar cells,batteries,wearable devices,bio-implants,soft robotics,and biomimetic applications.Recently,flexible electronic devices have been developed using a variety of materials such as organic,carbon-based,and inorganic semiconducting materials.Silicon(Si)owing to its mature fabrication process,excellent electrical,optical,thermal properties,and cost efficiency,remains a compelling material choice for flexible electronics.Consequently,the research on ultra-thin Si in the context of flexible electronics is studied rigorously nowadays.The thinning of Si is crucially important for flexible electronics as it reduces its bending stiffness and the resultant bending strain,thereby enhancing flexibility while preserving its exceptional properties.This review provides a comprehensive overview of the recent efforts in the fabrication techniques for forming ultra-thin Si using top-down and bottom-up approaches and explores their utilization in flexible electronics and their applications.
基金financial support from the RGC Senior Research Fellowship Scheme(SRFS2122-5S04)General Research Fund(15304322)+1 种基金RGC Postdoctoral Fellowship(PDFS2324-5S10)State Key Laboratory for Ultraprecision Machining Technology(1-BBXR).
文摘The burgeoning interest in flexible electronics necessitates the creation of patterning technology specifically tailored for flexible substrates and complex surface morphologies.Among a variety of patterning techniques,transfer printing emerges as one of the most efficient,cost-effective,and scalable methods.It boasts the ability for high-throughput fabrication of 0–3D micro-and nano-structures on flexible substrates,working in tandem with traditional lithography methods.This review highlights the critical issue of transfer printing:the flawless transfer of devices during the pick-up and printing process.We encapsulate recent advancements in numerous transfer printing techniques,with a particular emphasis on strategies to control adhesion forces at the substrate/device/stamp interfaces.These strategies are employed to meet the requirements of competing fractures for successful pick-up and print processes.The mechanism,advantages,disadvantages,and typical applications of each transfer printing technique will be thoroughly discussed.The conclusion section provides design guidelines and probes potential directions for future advancements.
基金Supported by the State Scholarship Fund of Chinathe Open Research Fund of Shanghai Key Laboratory of Multidimensional Information Processing of East China Normal University
文摘As a potential flexible substrate for flexible electronics, a polymer-sandwiched ultra-thin silicon platform is stud- ied. SU-8 photoresist coated on the silicon membrane improves its flexibility as shown by an ANSYS simulation. Using the plasma enhanced chemical vapor deposited Si02/Si3N4 composite film as an etching mask, a 4＂ silicon- （100） wafer is thinned to 26[tm without rupture in a 30wt.% KOH solution. The thinned wafer is coated on both sides with 20 pm of SU-8 photoresist and is cut into strips. Then the strips are bent by a caliper to measure its bending radius. A sector model of bending deformation is adopted to estimate the radius of curvature. The determined minimal bending radius of the polymer-sandwiched ultra-thin silicon layer is no more than 3.3mm. The fabrication process of this sandwich structure can be used as a post-fabrication process for high performance flexible electronics.
基金supported by the National Natural Science Foundation of China (Grants 11572022 and 11172022)
文摘Laminated hard-soft integrated structures play a significant role in the fabrication and development of flexible electronics devices. Flexible electronics have advantageous characteristics such as soft and light-weight, can be folded,twisted, flipped inside-out, or be pasted onto other surfaces of arbitrary shapes. In this paper, an analytical model is presented to study the mechanics of laminated hard-soft structures in flexible electronics under a stickup state. Thirdorder polynomials are used to describe the displacement field,and the principle of virtual work is adopted to derive the governing equations and boundary conditions. The normal strain and the shear stress along the thickness direction in the bimaterial region are obtained analytically, which agree well with the results from finite element analysis. The analytical model can be used to analyze stickup state laminated structures, and can serve as a valuable reference for the failure prediction and optimal design of flexible electronics in the future.
文摘This study employs theoretical analysis to explore the application prospects of flexible electronics technology in wearable devices. The research first reviews the development history and theoretical foundations of flexible electronics technology, including materials science, electronic engineering, and human-computer interaction theory. Through systematic analysis, the study evaluates the theoretical potential of flexible displays, flexible sensors, and flexible energy storage devices in wearable technology. The research finds that flexible electronics technology can significantly improve the comfort, functionality, and durability of wearable devices. Theoretical analysis indicates that flexible sensors have unique advantages in physiological monitoring and human-computer interaction, while flexible displays and batteries may revolutionize the form and usage patterns of wearable devices. However, the study also points out theoretical challenges faced by flexible electronics technology, such as material stability and feasibility of large-scale manufacturing. To address these challenges, the research proposes an interdisciplinary research framework, emphasizing the synergistic innovation of materials science, electronic engineering, and ergonomics. Finally, the study envisions the theoretical prospects of integrating flexible electronics with other emerging technologies, providing directions for future research.
文摘Flexible electronics is an emerging technology,which breaks through the constraints of traditional rigid electronics,enabling electronic devices to adapt to various complex application scenarios.Meanwhile,a variety of functions including sensing,actuation and energy harvesting,promote flexible electronics to be widely used in healthcare,robotics,Internet of Things,and so on.Micro/nanomanufacturing is the key technology to realize flexible electronics.Through micro/nanomanufacturing,various micro/nano-scale electronic components such as transistors and sensors can be precisely fabricated on flexible substrates,endowing flexible electronics with excellent performance.On the other hand,the development of flexible electronics also provides new challenges for micro/nanomanufacturing,due to the new flexible materials and device morphology.Currently,flexible electronics and micro/nanomanufacturing have attracted great at-tention from researchers around the world.Scientists explore new materials and techniques to further expand the applications of flexible electronics.On this basis,we have organized a special topic on“Flexible Electronics and Micro/Nanomanufacturing”in National Science Open(NSO)to discuss the development of flexible electronics.The topic focuses on key issues in the design and manufacturing of flexible electronics.We have invited nine scientists from different fields to present their latest research findings and prospective analyses of flexible electronics systematically.
基金supported by the National Natural Science Foundation of China(nos.52188102 and 51925503)the Science and Technology Development Fund of Macao SAR(file na.0117/2024/AMJ)+1 种基金Zhuhai UM Science&Technology Research Institute(CP-009-2024)the State Key Laboratory of Intelligent Manufacturing Equipment and Tech-nology(IMETKF2024003),HUST,Wuhan,China.
文摘The realization of natural and authentic facial expressions in humanoid robots poses a challenging and prominent research domain,encompassing interdisciplinary facets including mechanical design,sensing and actuation control,psychology,cognitive science,flexible electronics,artificial intelligence(AI),etc.We have traced the recent developments of humanoid robot heads for facial expressions,discussed major challenges in embodied AI and flexible electronics for facial expression recognition and generation,and highlighted future trends in this field.Developing humanoid robot heads with natural and authentic facial expressions demands collaboration in interdisciplinary fields such as multi-modal sensing,emotional computing,and human-robot interactions(HRIs)to advance the emotional anthropomorphism of humanoid robots,bridging the gap between humanoid robots and human beings and enabling seamless HRIs.
基金supported by financial support from KONE Foundation,the Research Council of Finland(grant no.331368)project DURATRANS(364364,2024–2027,under the framework of M-ERA.Net)+2 种基金the Materials Research Infrastructure(MARI)at the University of Turku for infrastructural facilitiessupport by the UK Engineering and Physical Sciences Research Council(EPSRC)(grant no.:EP/Y011457/1)by the RAEng/Leverhulme Trust Research Fellowship(grant no.:LTRF-2324-20-129)。
文摘The microfractals of leaf skeletons can be effective substrates for flexible electronics due to their high surface-to-volume ratio,transparency,breathability and flexibility.The challenge lies in replicating these fractal surfaces at the microscale in a way that is scalable,freestanding,and integrable with various materials.In this study,we present a novel method for the biomimetic microfabrication of leafskeleton-based fractal surfaces.We utilized a modified electrospinning method,replacing the fiber collector with a metalized biotic collector to replicate the microstructures.The biomimetic microfractals demonstrated~90%replication accuracy,>80%transparency,good stretchability,and breathability,and were freestanding.The method is versatile,allowing for the use of a wide range of polymers in biomimetic microfabrication.For application in flexible electronics,biomimetic conductive fractal patterns(BCFP)were fabricated by immobilizing Ag Nanowires(AgNW)using a simple spraybased method.The BCFP exhibited high conductivity with sheet resistances<20Ωsq-1 while maintaining good transparencies.The BCFP adheres conformally to human skin,acting as an electronic skin(e-skin).To demonstrate the application,the BCFP was used to fabricate a tactile pressure sensor.In addition to their excellent transparency at low sheet resistances,stretchability,moisture resistance,and tight conformal bonding with the target surface,the BCFP also allows the evaporation of perspiration,making them suitable for long-term use as epidermal sensors.The application of BCFP in advanced bionic skin was demonstrated through gesture monitoring experiments.
基金supported by the National Natural Science Foundation of China(52573131,22203015)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZZ127)+2 种基金National Key Research and Development Program of China(2020YFA0710303)Fujian Provincial Natural Science Foundation of China(2024J01626)Fujian Provincial Health Technology Project(2024QNA016)。
文摘Ionogels,with their combined properties of flexibility,excellent ionic conductivity,and biomechanical characteristics similar to biological tissues,have become key materials in flexible electronics,exhibiting enormous appli-cation potential in fields such as health monitoring and smart wearables.However,ionogels are susceptible to mechanical damage.Under large deformations and continuous mechan-ical loading,structural damage and device failure are in-evitable.Self-healing ability can significantly improve the reliability,service life,and safety of devices.This review dis-cusses the latest progress in self-healing ionogels,covering self-healing mechanisms,as well as the design,preparation,and applications of various ionogel-based flexible electronic devices,including wearable sensors,flexible triboelectric na-nogenerators,supercapacitors,flexible displays,and soft ro-bots.Furthermore,based on the self-healing mechanisms of ionogels and the design and manufacturing of related pro-ducts,we put forward perspectives on the development of flexible electronics.This review is expected to accelerate the development of self-healing ionogels in the applications of various flexible electronic devices.
基金financially supported by the Department of Science and Technology of Guangdong Province (2023QN10L141)the Innovation and Entrepreneurship Team of Guangdong Provincial Pearl River Talents Program (2019ZT08L101)+1 种基金the Program for Shenzhen Science and Technology Innovation Committee (JSGGKQTD20221101115701006)the Guangdong Basic Research Center of Excellence for Aggregate Science。
文摘The rapid expansion of the Internet of Things(IoT)and wearable technologies has driven the demand for flexible,lightweight,and multifunctional electronic devices.However,conventional rigid electronics often fall short in meeting the requirements for conformability,comfort,and durability in applications such as health monitoring,soft robotics,and human-machine interfaces(HMIs)[1].While two-dimensional materials like graphene and transition metal dichalcogenides have been extensively explored,their limitations in electrical conductivity,tunable surface properties,and scalable synthesis have spurred the search for alternative materials[2].
基金This work was supported by the financial support from the National Key Research and Development Program of China(Nos.2021YFA1202600 and 2023YFF0719600)the National Natural Science Foundation of China(Nos.U23A20322,92164108,62174164 and U22A2075)+3 种基金Natural Science Foundation of Zhejiang Province(No.LR23E020001)Hunan Provincial Natural Science Foundation(Nos.2023JJ50009 and 2023JJ30599)Talent Plan of Shanghai Branch,Chinese Academy of Sciences(No.CASSHB-QNPD-2023-022)Ningbo Technology Project(No.2022A-007-C).
文摘Self-rectifying memristor(SRM)arrays hold tremendous potential in high-density data storage and energy efficient neuromorphic computing.However,SRM arrays are mostly developed on rigid substrates and lack mechanical flexibility,limiting their applications in intelligent electronic skin,wearable technologies,etc.Here,we present a high performance SRM array based on Pt/HfO_(2)/Ta_(2)O_(5−x)/Ti heterojunctions,which can be fabricated on a flexible polyimides(PI)substrate and demonstrates exceptional memristive performance under bending conditions(bending radius(R)=1 cm,rectifying ratio>10^(4),retention time>10^(4) s and endurance>105 cycles).We demonstrate a 16×16 flexible memristor array offering noise filtering and data storage capabilities,which can be used to accurately process and store the signals transmitted by a pressure sensor array.This research represents an important advancement towards the realization of next-generation high-performance flexible electronics.
基金supported by the National Natural Science Foundation of China(Nos.62174086,62474096,and 62288102)Basic Research Program of Jiangsu(No.BK20243057)+2 种基金Outstanding Youth Foundation of Jiangsu Province(No.BK20240139)Qinglan Project of Jiangsu Province of ChinaNational Entrepreneurship Training Program for College Students(No.202510293240E).
文摘Flexible electronics have emerged as a revolutionary paradigm to unlock novel possibilities across diverse fields such as wearables,healthcare,and wireless communications.Among the numerous materials,liquid metal(LM)thin films,characterized by high electrical conductivity,high thermal conductivity,high ductility,and biocompatibility,have become crucial materials for the fabrication of flexible electronics.Nevertheless,the current state-of-the-art technologies still face several challenges including complex preparation processes,poor compatibility with substrates,and insufficient mechanical stability.In this comprehensive review,the innovative preparation technologies for LM thin films including patterned printing methods,various coatings techniques,and interface-driven assembly approaches have been systematically summarized.The underlying design principle which involves modulating the ratio of composition materials and process conditions,are elucidated in detail.Moreover,their innovative applications in flexible electronics are concluded.Finally,we provide a forward-looking perspective on the future research and development trends in this burgeoning field.It aims to guide and inspire further scientific investigations and technological advancements.
基金supported by the National Science and Technology Innovation 2030 Major Project(Grant No.2022ZD0208601)the National Natural Science Foundation of China(Grant No.52105593 and 51975513)the Natural Science Foundation of Zhejiang Province,China(No.LR20E050003)。
文摘In the past decade,the global industry and research attentions on intelligent skin-like electronics have boosted their applications in diverse fields including human healthcare,Internet of Things,human–machine interfaces,artificial intelligence and soft robotics.Among them,flexible humidity sensors play a vital role in noncontact measurements relying on the unique property of rapid response to humidity change.This work presents an overview of recent advances in flexible humidity sensors using various active functional materials for contactless monitoring.Four categories of humidity sensors are highlighted based on resistive,capacitive,impedance-type and voltage-type working mechanisms.Furthermore,typical strategies including chemical doping,structural design and Joule heating are introduced to enhance the performance of humidity sensors.Drawing on the noncontact perception capability,human/plant healthcare management,human-machine interactions as well as integrated humidity sensor-based feedback systems are presented.The burgeoning innovations in this research field will benefit human society,especially during the COVID-19 epidemic,where cross-infection should be averted and contactless sensation is highly desired.
基金support from the Natural Sciences and Engineering Research Council of Canada(NSERC)the Canada Foundation for Innovation(CFI),and the Canada Research Chairs Program(H.Zeng).
文摘Flexible electronics have emerged as an exciting research area in recent years,serving as ideal interfaces bridging biological systems and conventional electronic devices.Flexible electronics can not only collect physiological signals for human health monitoring but also enrich our daily life with multifunctional smart materials and devices.Conductive hydrogels(CHs)have become promising candidates for the fabrication of flexible electronics owing to their biocompatibility,adjustable mechanical flexibility,good conductivity,and multiple stimuli-responsive properties.To achieve on-demand mechanical properties such as stretchability,compressibility,and elasticity,the rational design of polymer networks via modulating chemical and physical intermolecular interactions is required.Moreover,the type of conductive components(eg,electron-conductive materials,ions)and the incorporation method also play an important role in the conductivity of CHs.Electron-CHs usually possess excellent conductivity,while ion-CHs are generally transparent and can generate ion gradients within the hydrogel matrices.This mini review focuses on the recent advances in the design of CHs,introducing various design strategies for electron-CHs and ion-CHs employed in flexible electronics and highlighting their versatile applications such as biosensors,batteries,supercapacitors,nanogenerators,actuators,touch panels,and displays.
文摘Wearable electronics offer incredible benefits in mobile healthcare monitoring,sensing,portable energy harvesting and storage,human-machine interactions,etc.,due to the evolution of rigid electronics structure to flexible and stretchable devices.Lately,transition metal carbides and nitrides(MXenes)are highly regarded as a group of thriving two-dimensional nanomaterials and extraordinary building blocks for emerging flexible electronics platforms because of their excellent electrical conductivity,enriched surface functionalities,and large surface area.This article reviews the most recent developments in MXene-enabled flexible electronics for wearable electronics.Several MXeneenabled electronic devices designed on a nanometric scale are highlighted by drawing attention to widely developed nonstructural attributes,including 3D configured devices,textile and planer substrates,bioinspired structures,and printed materials.Furthermore,the unique progress of these nanodevices is highlighted by representative applications in healthcare,energy,electromagnetic interference(EMI)shielding,and humanoid control of machines.The emerging prospects of MXene nanomaterials as a key frontier in nextgeneration wearable electronics are envisioned and the design challenges of these electronic systems are also discussed,followed by proposed solutions.
基金partially supported by the National Natural Science Foundation of China Key Project (91748206)Dean’s Research Funding and the Frontier Project of the Chinese Academy of Sciences
文摘Recent breakthrough in eutectic gallium-indium alloy has revealed its great potential in modern electronic engineering. Here, we established a general method towards super-fast fabrication of flexible electronics via semi-liquid metal and adhesion-selection enabled rolling and transfer (SMART) printing on various substrates. Based on the semiliquid metal and its adhesion-difference on specifically designed target materials, we demonstrated that the rolling and transfer printing method could serve to rapidly manufacture a wide variety of complicated patterns with high resolution and large size. The process is much faster than most of the currently existing electronic fabrication strategies including liquid metal printing ever developed, and the cost either in time or consumption rate is rather low. As illustrated, a series of functional flexible and stretchable electronics such as multiple layer and large area circuits were fabricated to show their superior merit in combination with electrical conductivity and deformability. In addition, it was also demonstrated that the electronics fabricated in this way exhibited good repeatablity. A most noteworthy advantage is that all the fabrication processes could be highly automatic in the sense that user-friendly machines can thus be developed. This method paves a practical way for super-fast soft electronics manufacture and is expected to play an important role in the coming industry and consumer electronics.
