Stretchable electronics that monitor joint activity and treat diseases based on liquid metal could be used in the development of healthcare applications.Such devices can be seamlessly integrated with human skin.Howeve...Stretchable electronics that monitor joint activity and treat diseases based on liquid metal could be used in the development of healthcare applications.Such devices can be seamlessly integrated with human skin.However,most high-precision microstructures and complex patterns are difficult to fabricate due to the limitations of conventional fabrication solutions,resulting in suboptimal performance under practical conditions.Here,a liquid-metal stretchable system utilizing natural leaf veins was reported as microstructures,which was based on a biomimetic concept and utilized an all-solution process for the preparation of complex microstructures.The systems are ultra-high tensile(800%tensile strain),environmentally stable(20 days)and mechanically durable(300-cycle).The system can accurately recognize the wearer's finger bending level as well as simple gesture signals.At the same time,the system acts as a wearable heater,which can realize the fast heating behavior of heating up to 50℃in 3 min under the human body-safe voltage(1.5 V).The tensile stability is demonstrated by the heterogeneous integration of lasers(405 nm)with the system interconnects for a stretchable and wearable light source.展开更多
Stretchable electronics represents a direction of recent development in next-generation semiconductor devices.Such systems have the potential to offer the performance of conventional wafer-based technologies,but they ...Stretchable electronics represents a direction of recent development in next-generation semiconductor devices.Such systems have the potential to offer the performance of conventional wafer-based technologies,but they can be stretched like a rubber band,twisted like a rope, bent over a pencil,and folded like a piece of paper.Isolating the active devices from strains associated with such deformations is an important aspect of design.One strategy involves the shielding of the electronics from deformation of the substrate through insertion of a compliant adhesive layer. This paper establishes a simple,analytical model and validates the results by the finite element method.The results show that a relatively thick,compliant adhesive is effective to reduce the strain in the electronics,as is a relatively short film.展开更多
Various methods have been developed to fabricate highly stretchable electronics. Recent studies show that over 100% two dimensional stretchability can be achieved by mesh structure of brittle functioning devices inter...Various methods have been developed to fabricate highly stretchable electronics. Recent studies show that over 100% two dimensional stretchability can be achieved by mesh structure of brittle functioning devices interconnected with serpentine bridges. Kim et al show that pressing down an inflated elastomeric thin film during transfer printing introduces two di- mensional prestrain, and therefore further improves the system stretchability. This paper gives a theoretical study of this process, through both analytical and numerical approaches. Simple analytical solutions are obtained for meridional and circumferential strains in the thin film, as well as the maximum strain in device islands, which all agree reasonably well with finite element analysis.展开更多
The performance of the flexibility and stretchability of flexible electronics depends on the mechanical structure design,for which a great progress has been made in past years.The use of prestrain in the substrate,cau...The performance of the flexibility and stretchability of flexible electronics depends on the mechanical structure design,for which a great progress has been made in past years.The use of prestrain in the substrate,causing the compression of the transferred interconnects,can provide high elastic stretchability.Recently,the nonbuckling interconnects have been designed,where thick bar replaces thin ribbon layout to yield scissor-like in-plane deformation instead of in-or out-of-plane buckling modes.The nonbuckling interconnect design achieves significantly enhanced stretchability.However,combined use of prestrain and nonbuckling interconnects has not been explored.This paper aims to study the mechanical behavior of nonbuckling interconnects bonded to the prestrained substrate analytically and numerically.It is found that larger prestrain,longer straight segment,and smaller arc radius yield smaller strain in the interconnects.On the other hand,larger prestrain can also cause larger strain in the interconnects after releasing the prestrain.Therefore,the optimization of the prestrain needs to be found to achieve favorable stretchability.展开更多
Stretchable electronics, which offers the performance of conventional wafer-based devices and mechan- ical properties of a rubber band, enables many novel applications that are not possible through conven- tional elec...Stretchable electronics, which offers the performance of conventional wafer-based devices and mechan- ical properties of a rubber band, enables many novel applications that are not possible through conven- tional electronics due to its brittle nature. One effective strategy to realize stretchable electronics is to design the inorganic semiconductor material in a stretchable format on a compliant elastomeric substrate. Engineering thermal management is essential for the development of stretchable electronics to avoid adverse thermal effects on its performance as well as in applications involving human body and biological tissues where even 1-2℃ temperature increase is not allowed. This article reviews the recent advances in thermal management of stretchable inorganic electronics with focuses on the thermal models and their comparisons to experiments and finite element simulations.展开更多
Soft electronics have seen extensive development due to their lightness,outstanding mechanical flexibility,and biocompatibility,which make them ideal for a variety of applications,including health monitoring,human-mac...Soft electronics have seen extensive development due to their lightness,outstanding mechanical flexibility,and biocompatibility,which make them ideal for a variety of applications,including health monitoring,human-machine interfaces,and advanced augmented reality/virtual reality communications[1,2].Ionic liquid(IL)-based conductive hydrogels are typically made up of a polymer network swollen with IL,which are organic salts in a liquid state at or near room temperature,rather than traditional inorganic/organic salt electrolyte solutions[3-5].These hydrogels leverage the unique properties of IL,such as high ionic conductivity,nonvolatility,and thermal stability,to create a flexible conductive material suitable for various applications in soft electronics,such as actuators,wearable sensors,and stretchable energy generation/storage devices[6-8].展开更多
The booming development of wearable devices has aroused increasing interests in flexible and stretchable devices.With mechanosensory functionality,these devices are highly desirable on account of their wide range of a...The booming development of wearable devices has aroused increasing interests in flexible and stretchable devices.With mechanosensory functionality,these devices are highly desirable on account of their wide range of applications in electronic skin,personal healthcare,human–machine interfaces and beyond.However,they are mostly limited by single electrical signal feedback,restricting their diverse applications in visualized mechanical sensing.Inspired by the mechanochromism of structural color materials,interactively stretchable electronics with optical and electrical dual-signal feedbacks are recently emerged as novel sensory platforms,by combining both of their sensing mechanisms and characteristics.Herein,recent studies on interactively stretchable electronics based on structural color materials are reviewed.Following a brief introduction of their basic components(i.e.,stretchable electronics and mechanochromic structural color materials),two types of interactively stretchable electronics with respect to the nanostructures of mechanochromic materials are outlined,focusing primarily on their design considerations and fabrication strategies.Finally,the main challenges and future perspectives of these emerging devices are discussed.展开更多
Triboelectric nanogenerators(TENGs)are emerging as new technologies to harvest electrical power from mechanical energy.With the distinctive working mechanism of triboelectric nanogenerators,they attract particular int...Triboelectric nanogenerators(TENGs)are emerging as new technologies to harvest electrical power from mechanical energy.With the distinctive working mechanism of triboelectric nanogenerators,they attract particular interest in healthcare monitoring,wearable electronics,and deformable energy harvesting,which raises the requirement for highly conformable devices with substantial energy outputs.Here,a simple,low-cost strategy for fabricating stretchable triboelectric nanogenerators with ultra-high electrical output is developed.The TENG is prepared using PTFE micron particles(PPTENG),contributing a different electrostatic induction process compared to TENG based on dielectric films,which was associated with the dynamics of particle motions in PP-TENG.The generator achieved an impressive voltage output of 1000 V with a current of 25 lA over a contact area of 40320 mm^(2).Additionally,the TENG exhibits excellent durability with a stretching strain of 500%,and the electrical output performance does not show any significant degradation even after 3000 cycles at a strain of 400%.The unique design of the device provides high conformability and can be used as a self-powered sensor for human motion detection.展开更多
There has been ongoing keen interest to mold electronic devices into desired shapes and be laid on desired configurable surfaces. In specific, the ability to design materials that can bend, twist, compress and stretch...There has been ongoing keen interest to mold electronic devices into desired shapes and be laid on desired configurable surfaces. In specific, the ability to design materials that can bend, twist, compress and stretch repeatedly, while still able to maintain its full capability as conductors or electrodes, has led to numerous efforts to develop flexible and stretchable (bio)devices that are both technologically challenging and environmentally friendly (e.g. biodegradable). In this review, we highlight several recent significant results that have made impacts toward the field of flexible and stretchable electronics, sensors and power sources.展开更多
Recently, we developed a nonbuckling interconnect design that provides an effective approach to simultaneously achieving high elastic stretchability, easiness for encapsulation, and high electric performance for stret...Recently, we developed a nonbuckling interconnect design that provides an effective approach to simultaneously achieving high elastic stretchability, easiness for encapsulation, and high electric performance for stretchable electronics. This paper aims to systematically study its mechanical and electric behaviors, including comparisons of the nonbuckling and buckling interconnect designs on stretchability, effects of the thickness on electric performance, and modeling and experimental investigations on the finite deformation mechanics. It is found that the results on stretchability depend on the layouts. Long straight segments and small arc radii for nonbuckling interconnects yield an enhancement of stretchability, which is much better than that of buckling designs. On the other hand, shorter straight segments or thicker interconnects are better to lower the resistances of interconnects.Therefore, optimization of the designs needs to balance the requirements of both the mechanical and electric performances. The finite deformation of interconnects during stretching is analyzed. The established analytic model is well validated by both the finite element modeling and experimental investigations. This work is key for providing the design guidelines for nonbucklingbased stretchable electronics.展开更多
The field of stretchable electronics mainly includes electronic products conformal with tissues,being integrated into skin or clothing.Since these products need to work during deformation,their requirements for materi...The field of stretchable electronics mainly includes electronic products conformal with tissues,being integrated into skin or clothing.Since these products need to work during deformation,their requirements for materials focus on stretchability and conductivity.Liquid metals are excellent materials with these properties.However,liquid metals have extremely high surface tension at room temperature,which will spontaneously form a spherical shape and are difficult to form the shape required by stretchable devices,which is the biggest obstacle to their development in this emerging field.Therefore,the emphasis is placed on the principle of overcoming the high surface tension in this review,and various methods of using liquid metals to fabricate stretchable electronic devices based on these principles have been linked.Liquid metals show promise in the convenience of sensing,energy harvesting,etc.The existing challenges and opportunities are also discussed here.展开更多
Crystalline silicon（c-Si） is unambiguously the most important semiconductor that underpins the development of modern microelectronics and optoelectronics, though the rigid and brittle nature of bulk c-Si makes it di...Crystalline silicon（c-Si） is unambiguously the most important semiconductor that underpins the development of modern microelectronics and optoelectronics, though the rigid and brittle nature of bulk c-Si makes it difficult to implement directly for stretchable applications. Fortunately, the one-dimensional（1 D） geometry, or the line-shape, of Si nanowire（SiNW） can be engineered into elastic springs, which indicates an exciting opportunity to fabricate highly stretchable 1 D c-Si channels. The implementation of such line-shape-engineering strategy demands both a tiny diameter of the SiNWs, in order to accommodate the strains under large stretching, and a precise growth location, orientation and path control to facilitate device integration. In this review, we will first introduce the recent progresses of an in-plane self-assembly growth of SiNW springs, via a new in-plane solid-liquidsolid（IPSLS） mechanism, where mono-like but elastic SiNW springs are produced by surface-running metal droplets that absorb amorphous Si thin film as precursor. Then, the critical growth control and engineering parameters, the mechanical properties of the SiNW springs and the prospects of developing c-Si based stretchable electronics, will be addressed. This efficient line-shape-engineering strategy of SiNW springs, accomplished via a low temperature batch-manufacturing, holds a strong promise to extend the legend of modern Si technology into the emerging stretchable electronic applications, where the high carrier mobility, excellent stability and established doping and passivation controls of c-Si can be well inherited.展开更多
Stretchable electronics are crucial enablers for next-generation wearables intimately integrated into the human body.As the primary compliant conductors used in these devices,metallic nanostructure/elastomer composite...Stretchable electronics are crucial enablers for next-generation wearables intimately integrated into the human body.As the primary compliant conductors used in these devices,metallic nanostructure/elastomer composites often struggle to form conformal contact with the textured skin.Hybrid electrodes have been consequently developed based on conductive nanocomposite and soft hydrogels to establish seamless skin-device interfaces.However,chemical modifications are typically needed for reliable bonding,which can alter their original properties.To overcome this limitation,this study presents a facile fabrication approach for mechanically interlocked nanocomposite/hydrogel hybrid electrodes.In this physical process,soft microfoams are thermally laminated on silver nanowire nanocomposites as a porous interface,which forms an interpenetrating network with the hydrogel.The microfoam-enabled bonding strategy is generally compatible with various polymers.The resulting interlocked hybrids have a 28-fold improved interfacial toughness compared to directly stacked hybrids.These electrodes achieve firm attachment to the skin and low contact impedance using tissue-adhesive hydrogels.They have been successfully integrated into an epidermal sleeve to distinguish hand gestures by sensing mus-cle contractions.Interlocked nanocomposite/hydrogel hybrids reported here offer a promising platform to combine the benefits of both materials for epidermal devices and systems.展开更多
The rapid development of stretchable electronics made by circuits,microchips,and encapsulation elastomers has caused the production of a large amount of electronic waste(e-waste).The degradation of elastomers can high...The rapid development of stretchable electronics made by circuits,microchips,and encapsulation elastomers has caused the production of a large amount of electronic waste(e-waste).The degradation of elastomers can highly minimize the negative effects of e-wastes.However,chemicals that included acid,alkali,and organics were repeatedly used during the recycling process,which were environmentally unfriendly.Here,a water-modulation-degradation-reconstruction(WDR)polyvinylpyrrolidone(PVP)-honey composite(PHC)polymer-gel was developed and could be regarded as encapsulation elastomers to realize a fully recyclable water-degradable stretchable(WS)electronics with multi-functions.The stretchability of the PHC polymer-gel could be modulated by the change of its water retention.The Chip-integrated liquid metal(LM)circuits encapsulated with the modulated PHC encapsulation elastomer could withstand a strain value of~3000%.Moreover,we developed a WS biomedical sensor composed of PHC encapsulation elastomer,LM circuits,and microchips,which could be fully recycled by biodegrading it in water to reconstruct a new one.As before,the reconstructed WS biomedical sensor could still simultaneously realize the combination of ultra-stretchability,recycling,self-healing,self-adhesive,and self-conformal abilities.The results revealed that this study exercises a profound influence on the rational design of multi-functional WS electronics.展开更多
Stretchable/flexible electronics has attracted great interest and attention due to its potentially broad applications in bio-compatible systems. One class of these ultra-thin electronic systems has found promising and...Stretchable/flexible electronics has attracted great interest and attention due to its potentially broad applications in bio-compatible systems. One class of these ultra-thin electronic systems has found promising and important utilities in bio-integrated monitoring and therapeutic devices. These devices can conform to the surfaces of soft bio-tissues such as the epidermis, the epicardium, and the brain to provide portable healthcare functionalities. Upon contractions of the soft tissues, the electronics undergoes compression and buckles into various modes, depending on the stiffness of the tissue and the strength of the interfacial adhesion. These buckling modes result in different kinds of interfacial delamination and shapes of the deformed electronics, which are very important to the proper functioning of the bio- electronic devices. In this paper, detailed buckling mechanics of these thin-film electronics on elastomeric substrates is studied. The analytical results, validated by experiments, provide a very convenient tool for predicting peak strain in the electronics and the intactness of the interface under various conditions.展开更多
With practical interest in the future applications of next-generation electronic devices,it is imperative to develop new conductive interconnecting materials appropriate for modern electronic devices to replace tradit...With practical interest in the future applications of next-generation electronic devices,it is imperative to develop new conductive interconnecting materials appropriate for modern electronic devices to replace traditional rigid solder tin and silver paste of high melting temperature or corrosive solvent requirements.Herein,we design highly stretchable shape memory self-soldering conductive(SMSC)tape with reversible adhesion switched by temperature,which is composed of silver particles encapsulated by shape memory polymer.SMSC tape has perfect shape and conductivity memory property and anti-fatigue ability even under the strain of 90%.It also exhibits an initial conductivity of 2772 S cm^(−1) and a maximum tensile strain of~100%.The maximum conductivity could be increased to 5446 S cm^(−1) by decreasing the strain to 17%.Meanwhile,SMSC tape can easily realize a heating induced reversible strong-to-weak adhe-sion transition for self-soldering circuit.The combination of stable conductivity,excellent shape memory performance,and temperature-switching reversible adhesion enables SMSC tape to serve two functions of electrode and solder simultaneously.This provides a new way for conductive interconnecting materials to meet requirements of modern electronic devices in the future.展开更多
With the growing need on distributed power supply for portable electronics,energy harvesting from environment becomes a promising solution.Organic thermoelectric(TE)materials have advantages in intrinsic flexibility a...With the growing need on distributed power supply for portable electronics,energy harvesting from environment becomes a promising solution.Organic thermoelectric(TE)materials have advantages in intrinsic flexibility and low thermal conductivity,thus hold great prospect in applications as a flexible power generator from dissipated heat.Nevertheless,the weak electrical transport behaviors of organic TE materials have severely impeded their development.Moreover,compared with p-type organic TE materials,stable and high-performance n-type counterparts are more difficult to obtain.Here,we developed a n-type polyaniline-based hybrid with core-shell heterostructured Bi;S;@Bi nanorods as fillers,showing a Seebeck coefficient-159.4μV/K at room temperature.Further,a couple of n/p legs from the PANI-based hybrids were integrated into an elastomer substrate forming a stretchable thermoelectric generator(TEG),whose function to output stable voltages responding to temperature differences has been demonstrated.The in situ output performance of the TEG under stretching could withstand up to 75%elongation,and stability test showed little degradation over a one-month period in the air.This study provides a promising strategy to develop stable and high thermopower organic TEGs harvesting heat from environment as long-term power supply.展开更多
The development of reliable stretchable hybrid electronics(SHEs)requires the formation of soft/rigid interfaces that simultaneously achieve low electrical impedance,robust mechanical-electrical bonding,and high energy...The development of reliable stretchable hybrid electronics(SHEs)requires the formation of soft/rigid interfaces that simultaneously achieve low electrical impedance,robust mechanical-electrical bonding,and high energy dissipation capacity,which remains a critical challenge at present.In this work,an innovative alcohol vapor activation for dynamic covalent polyurethane elastomers was presented to address this problem.Specifically,through competitive intervene in the dynamic exchange of hindered urea bonds,ethanol forms irreversible polar urethane terminals,enabling precise surface polarity tuning and enhanced self-adhesion(peel strength of 2.04 N·cm^(-1))without compromising bulk mechanical properties.This activated surface facilitates significant improvements including high conductivity(8Ω·sq^(-1))through rapid nanofiller embedding,direct integration of rigid components with durable interfaces,exceptional electromechanical stability(resistance change less than 10%during bending,twisting,and stretching).The prepared SHEs demonstrate significant potential for applications in stretchable circuits,wearable control terminals,and healthcare monitoring systems.展开更多
Conductive ionic hydrogels(CIH)have been widely studied for the development of stretchable electronic devices,such as sensors,electrodes,and actuators.Most of these CIH are made into 3D or 2D shape,while 1D CIH(hydrog...Conductive ionic hydrogels(CIH)have been widely studied for the development of stretchable electronic devices,such as sensors,electrodes,and actuators.Most of these CIH are made into 3D or 2D shape,while 1D CIH(hydrogel fibers)is often difficult to make because of the low mechanical robustness of common CIH.Herein,we use gel spinning method to prepare a robust CIH fiber with high strength,large stretchability,and good conductivity.The robust CIH fiber is drawn from the composite gel of sodium polyacrylate(PAAS)and sodium carboxymethyl cellulose(CMC).In the composite CIH fiber,the soft PAAS presents good conductivity and stretchability,while the rigid CMC significantly enhances the strength and toughness of the PAAS/CMC fiber.To protect the conductive PAAS/CMC fiber from damage by water,a thin layer of hydrophobic polymethyl acrylate(PMA)or polybutyl acrylate(PBA)is coated on the PAAS/CMC fiber as a water-resistant and insulating cover.The obtained PAAS/CMC-PMA and PAAS/CMC-PBA CIH fibers present high tensile strength(up to 28 MPa),high tensile toughness(up to 43 MJ/m~3),and good electrical conductivity(up to 0.35 S/m),which are useful for textile-based stretchable electronic devices.展开更多
The demand of high-performance thin-film-shaped deformable electromagnetic interference(EMI)shielding devices is increasing for the next generation of wearable and miniaturized soft electronics.Although highly reflect...The demand of high-performance thin-film-shaped deformable electromagnetic interference(EMI)shielding devices is increasing for the next generation of wearable and miniaturized soft electronics.Although highly reflective conductive materials can effectively shield EMI,they prevent deformation of the devices owing to rigidity and generate secondary electromagnetic pollution simultaneously.Herein,soft and stretchable EMI shielding thin film devices with absorption-dominant EMI shielding behavior is presented.The devices consist of liquid metal(LM)layer and LM grid-patterned layer separated by a thin elastomeric film,fabricated by leveraging superior adhesion of aerosol-deposited LM on elastomer.The devices demonstrate high electromagnetic shielding effectiveness(SE)(SE_(T) of up to 75 dB)with low reflectance(SER of 1.5 dB at the resonant frequency)owing to EMI absorption induced by multiple internal reflection generated in the LM grid architectures.Remarkably,the excellent stretchability of the LM-based devices facilitates tunable EMI shielding abilities through grid space adjustment upon strain(resonant frequency shift from 81.3 to 71.3 GHz@33%strain)and is also capable of retaining shielding effectiveness even after multiple strain cycles.This newly explored device presents an advanced paradigm for powerful EMI shielding performance for next-generation smart electronics.展开更多
基金financially supported by the National Key Research and Development Program of China(No.2021YFA1401100)the National Natural Science Foundation of China(Nos.61825403 and 61921005)。
文摘Stretchable electronics that monitor joint activity and treat diseases based on liquid metal could be used in the development of healthcare applications.Such devices can be seamlessly integrated with human skin.However,most high-precision microstructures and complex patterns are difficult to fabricate due to the limitations of conventional fabrication solutions,resulting in suboptimal performance under practical conditions.Here,a liquid-metal stretchable system utilizing natural leaf veins was reported as microstructures,which was based on a biomimetic concept and utilized an all-solution process for the preparation of complex microstructures.The systems are ultra-high tensile(800%tensile strain),environmentally stable(20 days)and mechanically durable(300-cycle).The system can accurately recognize the wearer's finger bending level as well as simple gesture signals.At the same time,the system acts as a wearable heater,which can realize the fast heating behavior of heating up to 50℃in 3 min under the human body-safe voltage(1.5 V).The tensile stability is demonstrated by the heterogeneous integration of lasers(405 nm)with the system interconnects for a stretchable and wearable light source.
基金supported by NSF(DMI-0328162 and ECCS-0824129)the National Natural Science Foundation of China (10820101048)Ministry of Education of China,and the National Basic Research Program of China(2007CB936803).
文摘Stretchable electronics represents a direction of recent development in next-generation semiconductor devices.Such systems have the potential to offer the performance of conventional wafer-based technologies,but they can be stretched like a rubber band,twisted like a rope, bent over a pencil,and folded like a piece of paper.Isolating the active devices from strains associated with such deformations is an important aspect of design.One strategy involves the shielding of the electronics from deformation of the substrate through insertion of a compliant adhesive layer. This paper establishes a simple,analytical model and validates the results by the finite element method.The results show that a relatively thick,compliant adhesive is effective to reduce the strain in the electronics,as is a relatively short film.
基金Project supported by the NSF (Nos.DMI-0328162 and ECCS-0824129)the support from NSFCthe support from China Scholarship Council
文摘Various methods have been developed to fabricate highly stretchable electronics. Recent studies show that over 100% two dimensional stretchability can be achieved by mesh structure of brittle functioning devices interconnected with serpentine bridges. Kim et al show that pressing down an inflated elastomeric thin film during transfer printing introduces two di- mensional prestrain, and therefore further improves the system stretchability. This paper gives a theoretical study of this process, through both analytical and numerical approaches. Simple analytical solutions are obtained for meridional and circumferential strains in the thin film, as well as the maximum strain in device islands, which all agree reasonably well with finite element analysis.
文摘The performance of the flexibility and stretchability of flexible electronics depends on the mechanical structure design,for which a great progress has been made in past years.The use of prestrain in the substrate,causing the compression of the transferred interconnects,can provide high elastic stretchability.Recently,the nonbuckling interconnects have been designed,where thick bar replaces thin ribbon layout to yield scissor-like in-plane deformation instead of in-or out-of-plane buckling modes.The nonbuckling interconnect design achieves significantly enhanced stretchability.However,combined use of prestrain and nonbuckling interconnects has not been explored.This paper aims to study the mechanical behavior of nonbuckling interconnects bonded to the prestrained substrate analytically and numerically.It is found that larger prestrain,longer straight segment,and smaller arc radius yield smaller strain in the interconnects.On the other hand,larger prestrain can also cause larger strain in the interconnects after releasing the prestrain.Therefore,the optimization of the prestrain needs to be found to achieve favorable stretchability.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(Grant No.LR15A020001)the National Natural Science Foundation of China(Grant Nos.11502009,11372272 and 11321202)the National Basic Research Program of China(Grant No.2015CB351900)
文摘Stretchable electronics, which offers the performance of conventional wafer-based devices and mechan- ical properties of a rubber band, enables many novel applications that are not possible through conven- tional electronics due to its brittle nature. One effective strategy to realize stretchable electronics is to design the inorganic semiconductor material in a stretchable format on a compliant elastomeric substrate. Engineering thermal management is essential for the development of stretchable electronics to avoid adverse thermal effects on its performance as well as in applications involving human body and biological tissues where even 1-2℃ temperature increase is not allowed. This article reviews the recent advances in thermal management of stretchable inorganic electronics with focuses on the thermal models and their comparisons to experiments and finite element simulations.
基金supported by the National Natural Science Foundation of China (52303371)Guangdong Science and Technology Department (STKJ2023075, 2022A1515110209, and 2021B0301030005)+2 种基金Guangdong Education Department (2022KQNCX112)seed fund (GCII-Seed-202406) from GTIIT Changzhou Innovation Institutethe Key Discipline (KD) Fund, the Technion, and the Start-Up Fund from Guangdong Technion。
文摘Soft electronics have seen extensive development due to their lightness,outstanding mechanical flexibility,and biocompatibility,which make them ideal for a variety of applications,including health monitoring,human-machine interfaces,and advanced augmented reality/virtual reality communications[1,2].Ionic liquid(IL)-based conductive hydrogels are typically made up of a polymer network swollen with IL,which are organic salts in a liquid state at or near room temperature,rather than traditional inorganic/organic salt electrolyte solutions[3-5].These hydrogels leverage the unique properties of IL,such as high ionic conductivity,nonvolatility,and thermal stability,to create a flexible conductive material suitable for various applications in soft electronics,such as actuators,wearable sensors,and stretchable energy generation/storage devices[6-8].
基金funded by the National Natural Science Foundation of China(No.51873145)the Excellent Youth Foundation of Jiangsu Scientific Committee(No.BK20170065)+1 种基金the Qing Lan Project,the 5th 333 High-level Talents Training Project of Jiangsu Province(No.BRA2018340)the Six Talent Peaks Project in Jiangsu Province(No.XCL-79).
文摘The booming development of wearable devices has aroused increasing interests in flexible and stretchable devices.With mechanosensory functionality,these devices are highly desirable on account of their wide range of applications in electronic skin,personal healthcare,human–machine interfaces and beyond.However,they are mostly limited by single electrical signal feedback,restricting their diverse applications in visualized mechanical sensing.Inspired by the mechanochromism of structural color materials,interactively stretchable electronics with optical and electrical dual-signal feedbacks are recently emerged as novel sensory platforms,by combining both of their sensing mechanisms and characteristics.Herein,recent studies on interactively stretchable electronics based on structural color materials are reviewed.Following a brief introduction of their basic components(i.e.,stretchable electronics and mechanochromic structural color materials),two types of interactively stretchable electronics with respect to the nanostructures of mechanochromic materials are outlined,focusing primarily on their design considerations and fabrication strategies.Finally,the main challenges and future perspectives of these emerging devices are discussed.
基金financially supported by the Sichuan Provincial Science and Technology Fund for Distinguished Young Scholars,China(Grant No.2022JDJQ0028)Research Startup Fund by Sichuan University,China(Grant No.YJ202218).
文摘Triboelectric nanogenerators(TENGs)are emerging as new technologies to harvest electrical power from mechanical energy.With the distinctive working mechanism of triboelectric nanogenerators,they attract particular interest in healthcare monitoring,wearable electronics,and deformable energy harvesting,which raises the requirement for highly conformable devices with substantial energy outputs.Here,a simple,low-cost strategy for fabricating stretchable triboelectric nanogenerators with ultra-high electrical output is developed.The TENG is prepared using PTFE micron particles(PPTENG),contributing a different electrostatic induction process compared to TENG based on dielectric films,which was associated with the dynamics of particle motions in PP-TENG.The generator achieved an impressive voltage output of 1000 V with a current of 25 lA over a contact area of 40320 mm^(2).Additionally,the TENG exhibits excellent durability with a stretching strain of 500%,and the electrical output performance does not show any significant degradation even after 3000 cycles at a strain of 400%.The unique design of the device provides high conformability and can be used as a self-powered sensor for human motion detection.
基金funding from the Bill and Melinda Gates Foundation Grand Challenge Award (OPP1032970)
文摘There has been ongoing keen interest to mold electronic devices into desired shapes and be laid on desired configurable surfaces. In specific, the ability to design materials that can bend, twist, compress and stretch repeatedly, while still able to maintain its full capability as conductors or electrodes, has led to numerous efforts to develop flexible and stretchable (bio)devices that are both technologically challenging and environmentally friendly (e.g. biodegradable). In this review, we highlight several recent significant results that have made impacts toward the field of flexible and stretchable electronics, sensors and power sources.
基金supported by the National Natural Science Foundation of China(Grant Nos.11572323,11772331,11302038,51365013,and 11732004)the Chinese Academy of Sciences via the "Hundred Talent Program"+8 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB22040501)the State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology(Grant No.GZ1603)the State Key Laboratory of Digital Manufacturing Equipment and Technology,Huazhong University of Science and Technology(Grant No.DMETKF2017008)the Young Elite Scientists Sponsorship Program by CAST(Grant No.2015QNRC001)the Opening Fund of State Key Laboratory of Nonlinear Mechanicsthe Personnel Training Plan of Tianjin City in China for the Key Young and Middle-Aged Innovation Talentsthe National Key Research and Development Plan(Grant Nos.2016YFB0201600,2016YFB0201601,2017YFB0202800,and 2017YFB0202802)the Program for Changjiang Scholars,Innovative Research Team in University(PCSIRT)the 111 Project(Grant No.B14013)
文摘Recently, we developed a nonbuckling interconnect design that provides an effective approach to simultaneously achieving high elastic stretchability, easiness for encapsulation, and high electric performance for stretchable electronics. This paper aims to systematically study its mechanical and electric behaviors, including comparisons of the nonbuckling and buckling interconnect designs on stretchability, effects of the thickness on electric performance, and modeling and experimental investigations on the finite deformation mechanics. It is found that the results on stretchability depend on the layouts. Long straight segments and small arc radii for nonbuckling interconnects yield an enhancement of stretchability, which is much better than that of buckling designs. On the other hand, shorter straight segments or thicker interconnects are better to lower the resistances of interconnects.Therefore, optimization of the designs needs to balance the requirements of both the mechanical and electric performances. The finite deformation of interconnects during stretching is analyzed. The established analytic model is well validated by both the finite element modeling and experimental investigations. This work is key for providing the design guidelines for nonbucklingbased stretchable electronics.
基金supported by the National Natural Science Foundation of China(52173237 and 51903068)the Natural Science Foundation of Heilongjiang Province,China(YQ2020E001)。
文摘The field of stretchable electronics mainly includes electronic products conformal with tissues,being integrated into skin or clothing.Since these products need to work during deformation,their requirements for materials focus on stretchability and conductivity.Liquid metals are excellent materials with these properties.However,liquid metals have extremely high surface tension at room temperature,which will spontaneously form a spherical shape and are difficult to form the shape required by stretchable devices,which is the biggest obstacle to their development in this emerging field.Therefore,the emphasis is placed on the principle of overcoming the high surface tension in this review,and various methods of using liquid metals to fabricate stretchable electronic devices based on these principles have been linked.Liquid metals show promise in the convenience of sensing,energy harvesting,etc.The existing challenges and opportunities are also discussed here.
基金supported by the National Basic Research 973 Program(No.2014CB921101)the National Natural Science Foundation of China(No.61674075)+5 种基金the National Key Research and Development Program of China(No.2017YFA0205003)the Jiangsu Excellent Young Scholar Program(No.BK20160020)the Scientific and Technological Support Program in Jiangsu Province(No.BE2014147-2)the Jiangsu Shuangchuang Team's Personal Programthe Fundamental Research Funds for the Central Universitiesthe China Scholarship Council and the Postgraduate Program of Jiangsu Province(No.KYZZ160052)
文摘Crystalline silicon（c-Si） is unambiguously the most important semiconductor that underpins the development of modern microelectronics and optoelectronics, though the rigid and brittle nature of bulk c-Si makes it difficult to implement directly for stretchable applications. Fortunately, the one-dimensional（1 D） geometry, or the line-shape, of Si nanowire（SiNW） can be engineered into elastic springs, which indicates an exciting opportunity to fabricate highly stretchable 1 D c-Si channels. The implementation of such line-shape-engineering strategy demands both a tiny diameter of the SiNWs, in order to accommodate the strains under large stretching, and a precise growth location, orientation and path control to facilitate device integration. In this review, we will first introduce the recent progresses of an in-plane self-assembly growth of SiNW springs, via a new in-plane solid-liquidsolid（IPSLS） mechanism, where mono-like but elastic SiNW springs are produced by surface-running metal droplets that absorb amorphous Si thin film as precursor. Then, the critical growth control and engineering parameters, the mechanical properties of the SiNW springs and the prospects of developing c-Si based stretchable electronics, will be addressed. This efficient line-shape-engineering strategy of SiNW springs, accomplished via a low temperature batch-manufacturing, holds a strong promise to extend the legend of modern Si technology into the emerging stretchable electronic applications, where the high carrier mobility, excellent stability and established doping and passivation controls of c-Si can be well inherited.
基金We acknowledge the support from the National Key Research and Development Program of China(Grant No.2022YFA1405000)the Natural Science Foundation of Jiangsu Province,Major Project(Grant No.BK20212004)+1 种基金the National Natural Science Foundation of China(Grant No.62374083)the State Key Laboratory of Analytical Chemistry for Life Science(Grant No.5431ZZXM2205).
文摘Stretchable electronics are crucial enablers for next-generation wearables intimately integrated into the human body.As the primary compliant conductors used in these devices,metallic nanostructure/elastomer composites often struggle to form conformal contact with the textured skin.Hybrid electrodes have been consequently developed based on conductive nanocomposite and soft hydrogels to establish seamless skin-device interfaces.However,chemical modifications are typically needed for reliable bonding,which can alter their original properties.To overcome this limitation,this study presents a facile fabrication approach for mechanically interlocked nanocomposite/hydrogel hybrid electrodes.In this physical process,soft microfoams are thermally laminated on silver nanowire nanocomposites as a porous interface,which forms an interpenetrating network with the hydrogel.The microfoam-enabled bonding strategy is generally compatible with various polymers.The resulting interlocked hybrids have a 28-fold improved interfacial toughness compared to directly stacked hybrids.These electrodes achieve firm attachment to the skin and low contact impedance using tissue-adhesive hydrogels.They have been successfully integrated into an epidermal sleeve to distinguish hand gestures by sensing mus-cle contractions.Interlocked nanocomposite/hydrogel hybrids reported here offer a promising platform to combine the benefits of both materials for epidermal devices and systems.
基金supported by the Natural Science Foundation of Ningbo city,China(Grant No.2023J010)Natural Science Foundation of China(Grant Nos.52275343,62074013 and U23A20363)supported by the Fundamental Research Funds for the Provincial Universities of Zhejiang(Grant No.SJLY2024007)
文摘The rapid development of stretchable electronics made by circuits,microchips,and encapsulation elastomers has caused the production of a large amount of electronic waste(e-waste).The degradation of elastomers can highly minimize the negative effects of e-wastes.However,chemicals that included acid,alkali,and organics were repeatedly used during the recycling process,which were environmentally unfriendly.Here,a water-modulation-degradation-reconstruction(WDR)polyvinylpyrrolidone(PVP)-honey composite(PHC)polymer-gel was developed and could be regarded as encapsulation elastomers to realize a fully recyclable water-degradable stretchable(WS)electronics with multi-functions.The stretchability of the PHC polymer-gel could be modulated by the change of its water retention.The Chip-integrated liquid metal(LM)circuits encapsulated with the modulated PHC encapsulation elastomer could withstand a strain value of~3000%.Moreover,we developed a WS biomedical sensor composed of PHC encapsulation elastomer,LM circuits,and microchips,which could be fully recycled by biodegrading it in water to reconstruct a new one.As before,the reconstructed WS biomedical sensor could still simultaneously realize the combination of ultra-stretchability,recycling,self-healing,self-adhesive,and self-conformal abilities.The results revealed that this study exercises a profound influence on the rational design of multi-functional WS electronics.
基金partial support of this research by the National Natural Science Foundation of China(Grants 11272260,11172022,11572022,51075327,11302038)
文摘Stretchable/flexible electronics has attracted great interest and attention due to its potentially broad applications in bio-compatible systems. One class of these ultra-thin electronic systems has found promising and important utilities in bio-integrated monitoring and therapeutic devices. These devices can conform to the surfaces of soft bio-tissues such as the epidermis, the epicardium, and the brain to provide portable healthcare functionalities. Upon contractions of the soft tissues, the electronics undergoes compression and buckles into various modes, depending on the stiffness of the tissue and the strength of the interfacial adhesion. These buckling modes result in different kinds of interfacial delamination and shapes of the deformed electronics, which are very important to the proper functioning of the bio- electronic devices. In this paper, detailed buckling mechanics of these thin-film electronics on elastomeric substrates is studied. The analytical results, validated by experiments, provide a very convenient tool for predicting peak strain in the electronics and the intactness of the interface under various conditions.
基金This work is supported by National Key R&D Program of China(Grant No.2020YFA0711500)the National Natural Science Fund of China(51973095&52011540401).
文摘With practical interest in the future applications of next-generation electronic devices,it is imperative to develop new conductive interconnecting materials appropriate for modern electronic devices to replace traditional rigid solder tin and silver paste of high melting temperature or corrosive solvent requirements.Herein,we design highly stretchable shape memory self-soldering conductive(SMSC)tape with reversible adhesion switched by temperature,which is composed of silver particles encapsulated by shape memory polymer.SMSC tape has perfect shape and conductivity memory property and anti-fatigue ability even under the strain of 90%.It also exhibits an initial conductivity of 2772 S cm^(−1) and a maximum tensile strain of~100%.The maximum conductivity could be increased to 5446 S cm^(−1) by decreasing the strain to 17%.Meanwhile,SMSC tape can easily realize a heating induced reversible strong-to-weak adhe-sion transition for self-soldering circuit.The combination of stable conductivity,excellent shape memory performance,and temperature-switching reversible adhesion enables SMSC tape to serve two functions of electrode and solder simultaneously.This provides a new way for conductive interconnecting materials to meet requirements of modern electronic devices in the future.
基金supported by the National Key Research and Development Program of China(Grant Nos.2018YFA0702100 and 2018YFB0703600)the National Natural Science Foundation of China(Grant Nos.51872009 and 92066203)+1 种基金Beijing Nova Programme Interdisciplinary Cooperation Projectthe Fundamental Research Funds for the Central Universities,China。
文摘With the growing need on distributed power supply for portable electronics,energy harvesting from environment becomes a promising solution.Organic thermoelectric(TE)materials have advantages in intrinsic flexibility and low thermal conductivity,thus hold great prospect in applications as a flexible power generator from dissipated heat.Nevertheless,the weak electrical transport behaviors of organic TE materials have severely impeded their development.Moreover,compared with p-type organic TE materials,stable and high-performance n-type counterparts are more difficult to obtain.Here,we developed a n-type polyaniline-based hybrid with core-shell heterostructured Bi;S;@Bi nanorods as fillers,showing a Seebeck coefficient-159.4μV/K at room temperature.Further,a couple of n/p legs from the PANI-based hybrids were integrated into an elastomer substrate forming a stretchable thermoelectric generator(TEG),whose function to output stable voltages responding to temperature differences has been demonstrated.The in situ output performance of the TEG under stretching could withstand up to 75%elongation,and stability test showed little degradation over a one-month period in the air.This study provides a promising strategy to develop stable and high thermopower organic TEGs harvesting heat from environment as long-term power supply.
基金supported by the National Natural Science Foundation of China(Nos.52073099,52403062)the Guangdong Basic and Applied Basic Research Foundation(No.2024A1515010847)+2 种基金the Natural Science Foundation of Anhui Province(No.2408085QE169)the Scientific Research Project of Anhui Higher Education Institutions(No.2024AH050056)the Open Fund of Guangdong Highsun Meida New Materials Co.,Ltd.(No.20241031).
文摘The development of reliable stretchable hybrid electronics(SHEs)requires the formation of soft/rigid interfaces that simultaneously achieve low electrical impedance,robust mechanical-electrical bonding,and high energy dissipation capacity,which remains a critical challenge at present.In this work,an innovative alcohol vapor activation for dynamic covalent polyurethane elastomers was presented to address this problem.Specifically,through competitive intervene in the dynamic exchange of hindered urea bonds,ethanol forms irreversible polar urethane terminals,enabling precise surface polarity tuning and enhanced self-adhesion(peel strength of 2.04 N·cm^(-1))without compromising bulk mechanical properties.This activated surface facilitates significant improvements including high conductivity(8Ω·sq^(-1))through rapid nanofiller embedding,direct integration of rigid components with durable interfaces,exceptional electromechanical stability(resistance change less than 10%during bending,twisting,and stretching).The prepared SHEs demonstrate significant potential for applications in stretchable circuits,wearable control terminals,and healthcare monitoring systems.
基金supported by the National Natural Science Foundation of China(No.21778052 and No.21975240)by the Natural Science Foundation of Anhui Province(No.1908085J19)the Talent Research Foundation of Hefei University(No.18-19RC08)。
文摘Conductive ionic hydrogels(CIH)have been widely studied for the development of stretchable electronic devices,such as sensors,electrodes,and actuators.Most of these CIH are made into 3D or 2D shape,while 1D CIH(hydrogel fibers)is often difficult to make because of the low mechanical robustness of common CIH.Herein,we use gel spinning method to prepare a robust CIH fiber with high strength,large stretchability,and good conductivity.The robust CIH fiber is drawn from the composite gel of sodium polyacrylate(PAAS)and sodium carboxymethyl cellulose(CMC).In the composite CIH fiber,the soft PAAS presents good conductivity and stretchability,while the rigid CMC significantly enhances the strength and toughness of the PAAS/CMC fiber.To protect the conductive PAAS/CMC fiber from damage by water,a thin layer of hydrophobic polymethyl acrylate(PMA)or polybutyl acrylate(PBA)is coated on the PAAS/CMC fiber as a water-resistant and insulating cover.The obtained PAAS/CMC-PMA and PAAS/CMC-PBA CIH fibers present high tensile strength(up to 28 MPa),high tensile toughness(up to 43 MJ/m~3),and good electrical conductivity(up to 0.35 S/m),which are useful for textile-based stretchable electronic devices.
基金supported by National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(RS-2024-00335216,RS-2024-00407084 and RS-2023-00207836)Korea Environment Industry&Technology Institute(KEITI)through the R&D Project of Recycling Development for Future Waste Resources Program,funded by the Korea Ministry of Environment(MOE)(2022003500003).
文摘The demand of high-performance thin-film-shaped deformable electromagnetic interference(EMI)shielding devices is increasing for the next generation of wearable and miniaturized soft electronics.Although highly reflective conductive materials can effectively shield EMI,they prevent deformation of the devices owing to rigidity and generate secondary electromagnetic pollution simultaneously.Herein,soft and stretchable EMI shielding thin film devices with absorption-dominant EMI shielding behavior is presented.The devices consist of liquid metal(LM)layer and LM grid-patterned layer separated by a thin elastomeric film,fabricated by leveraging superior adhesion of aerosol-deposited LM on elastomer.The devices demonstrate high electromagnetic shielding effectiveness(SE)(SE_(T) of up to 75 dB)with low reflectance(SER of 1.5 dB at the resonant frequency)owing to EMI absorption induced by multiple internal reflection generated in the LM grid architectures.Remarkably,the excellent stretchability of the LM-based devices facilitates tunable EMI shielding abilities through grid space adjustment upon strain(resonant frequency shift from 81.3 to 71.3 GHz@33%strain)and is also capable of retaining shielding effectiveness even after multiple strain cycles.This newly explored device presents an advanced paradigm for powerful EMI shielding performance for next-generation smart electronics.
