Carbon fiber yarns（CFY） are promising as a new type of flexible building blocks for the construction of flexible architectures for the energy storage applications. The main hurdle with CFY is how to make them high e...Carbon fiber yarns（CFY） are promising as a new type of flexible building blocks for the construction of flexible architectures for the energy storage applications. The main hurdle with CFY is how to make them high energy and power capable by using economically and environmentally viable materials. Here,we report reduced graphene oxide（r GO） and Prussian blue（PB） coated CFY, derived from a facile electrochemical process at room temperature for supercapacitor electrodes. The PB coated CFY and r GO coated CFY electrodes exhibit the excellent gravimetric capacitance of 339 F/g and 160.2 F/g, respectively, in aqueous KCl electrolyte in three-electrode cell configuration. When we coupled these electrodes inside the flexible plastic tube and separated by the electrolyte wet filter paper in order to construct flexible architecture, the resulting device delivers excellent specific energy of 52.1 Wh/kg and 26.5 Wh/kg with offering specific power of 3100 W/kg and 14400 W/kg respectively, under a wide operating potential of1.8 V with excellent rate capability. The device shows high tolerance towards bending, and retained its efficiency to the capacitance after being bent at an angle of 360° for 200 bending cycles.展开更多
Recently, great efforts have been made in the fabrication of arbitrary warped devices to satisfy the requirement of wearable and lightweight electronic products. Direct growth of high crystalline quality films on flex...Recently, great efforts have been made in the fabrication of arbitrary warped devices to satisfy the requirement of wearable and lightweight electronic products. Direct growth of high crystalline quality films on flexible substrates is the most desirable method to fabricate flexible devices owing to the advantage of simple and compatible preparation technology with current semiconductor devices, while it is a very challenging work, and usually amorphous, polycrystalline or discontinuous single crystalline films are achieved. Here we demonstrate the direct growth of high-quality Bi2 Te3 single crystalline films on flexible polyimide substrates by the modified hot wall epitaxy technique. Experimental results reveal that adjacent crystallites are coherently coalesced to form a continuous film, although amounts of disoriented crystallites are generated due to fast growth rate. By inserting a quartz filter into the growth tube, the number density of disoriented crystallites is effectively reduced owing to the improved spiral interaction. Furthermore, flexible Bi2 Te3 photoconductors are fabricated and exhibit strong near-infrared photoconductive response under different degrees of bending, which also confirms the obtained fexible films suitable for electronic applications.展开更多
Flexible electronics demand multifunctional human-machine interfaces(HMIs)and organic user interfaces(OUIs).Existing deformable displays often rely on mechanical wires or hinges,limiting their thinness and flexibility...Flexible electronics demand multifunctional human-machine interfaces(HMIs)and organic user interfaces(OUIs).Existing deformable displays often rely on mechanical wires or hinges,limiting their thinness and flexibility.Incorporating sound features typically requires extra components,complicating design.In this study,we developed a lightweight,multifunctional display with a multishape bendable design and integrated sound capabilities.Using asymmetrical strain engineering on poly(vinylidene fluoride)(PVDF),we achieved bidirectional and complex deformations through electrical signals,eliminating the need for mechanical hinges.The PVDF actuator enables simultaneous sound emission and intricate shape transformations through rapid actuation and vibration.This design maintains the thinness and flexibility of organic light-emitting diode(OLED)technology.By controlling strain through PVDF polarization and applied electric field,we realized varied shape transformations and integrated these functions into a practical 6-inch OLED display.This approach enhances the functionality of flexible displays,expanding possibilities for future applications in flexible electronics.展开更多
Phase transition materials,which enable the switching of physical properties like second harmonic generation(SHG),have attracted great interest due to their wide applications,such as in sensors.However,although signif...Phase transition materials,which enable the switching of physical properties like second harmonic generation(SHG),have attracted great interest due to their wide applications,such as in sensors.However,although significant progress has been made in crystalline SHG switching phase transition materials,these materials typically show poor mechanical flexibility,hindering their applications in flexible wearable devices.Herein,for the first time,we reported a bendable photoluminescent molecular crystal(R)-octan-2-yl(E)-4-((4-(hexadecyloxy)-2-hydroxybenzylidene)amino)benzoate(R-EHAB),which shows a phase transition at around 320 K,accompanied by obvious SHG switching between high-SHG and low-SHG states.Significantly,R-EHAB demonstrates a low elastic modulus of 3.03 GPa,which is much lower than that of most molecular phase transition crystals.This enables its crystals to be easily bent into a semicircular shape and remain unchanged after bending-recovery cycles.To our knowledge,R-EHAB is the first bendable molecular crystal with a phase transition accompanied by SHG switching.This work would inspire the further exploration of more bendable phase transition crystals for potential application in next-generation functional devices.展开更多
In this study, we propose a novel combination of tunneling field-effect transistors （TFETs） with asymmetrically doped p^＋-i-n^＋ silicon nanowire （SiNW） channels on a bendable substrate. The combination of two n-...In this study, we propose a novel combination of tunneling field-effect transistors （TFETs） with asymmetrically doped p^＋-i-n^＋ silicon nanowire （SiNW） channels on a bendable substrate. The combination of two n-channel SiNW-TFETs （NWTFETs） in parallel and two p-channel NWTFETs in series operates as a two-input NOR logic gate. The component NWTFETs with the n- and p-channels exhibit subthreshold swings （SSs） of 69 and 53 mV·dec^-1, respectively, and the on/off current ratios are -106. The NOR logic operation is sustainable and reproducible for up to 1,000 bending cycles with a narrow transition width of -0.26 V. The mechanical bendability of the bendable NWTFETs shows that they are stable and have good fatigue properties. To the best of our knowledge, this is the first study on the electrical and mechanical characteristics of a bendable NOR logic gate composed of NWTFETs.展开更多
In this paper, we demonstrate the low-power functionality of silicon nanowire （SiNW）-assembled inverters on bendable plastics. Our bendable inverters are capable of operating at supply voltages as low as 0.8 V with ...In this paper, we demonstrate the low-power functionality of silicon nanowire （SiNW）-assembled inverters on bendable plastics. Our bendable inverters are capable of operating at supply voltages as low as 0.8 V with a switching （or standby） power consumption of -0.2 nW （or -6.6 pW）. The low-power inverting operation with a voltage gain of -18 is attributable to the near-ideal characteristics of the component transistors that have selectively thinned SiNW channels and exhibit low, symmetrical threshold voltages of 0.40 and -0.39 V and low subthreshold swing values of 81 and 65 mV/dec. Moreover, mechanical bendability reveals that the inverting operation has good, stable fatigue properties.展开更多
In this study, we propose complementary metal-oxide-semiconductor （CMOS） NOR logic gates consisting of silicon nanowire （NW） arrays on bendable substrates. A circuit consisting of two p-channel NW field-effect tra...In this study, we propose complementary metal-oxide-semiconductor （CMOS） NOR logic gates consisting of silicon nanowire （NW） arrays on bendable substrates. A circuit consisting of two p-channel NW field-effect transistors （NWFETs） in series and two n-channel NWFETs in parallel is constructed to operate a two- input CMOS NOR logic gate. The NOR logic gates operate at a low supply voltage of 1 V with a rail-to-rail logic swing and a high voltage gain of approximately -3.0. The exact NOR logic functionality is achieved owing to the superior electrical characteristics of the well-aligned p- and n-NWFETs, which are obtained using conventional Si-based CMOS technology. Moreover, the NOR logic gates exhibit stable characteristics and have good mechanical properties. The proposed bendable NW CMOS NOR logic gates are promising building blocks for future bendable integrated electronics.展开更多
In this study, we demonstrate the performance of silicon nanowire （SiNW） n-metal oxide semiconductor （MOS） and p-MOS ratioed inverters that are fabricated on bendable substrates. The electrical characteristics of ...In this study, we demonstrate the performance of silicon nanowire （SiNW） n-metal oxide semiconductor （MOS） and p-MOS ratioed inverters that are fabricated on bendable substrates. The electrical characteristics of the fabricated devices can be controlled by adjusting the load voltage. The logic swings of the n- and p-MOS ratioed inverters at a low supply voltage of 1V are 80% and 96%, respectively. The output voltage level of the p-MOS ratioed inverter is close to rail-to-rail operation. The device also exhibits stable characteristics with good fatigue properties. Our bendable SiNW ratioed inverters show promise as a candidate building block for future bendable electronics.展开更多
In this paper, we propose a novel construction of silicon nanowire （SiNW） negative-AND （NAND） logic gates on bendable plastic substrates and describe their electrical characteristics. The NAND logic gates with SiN...In this paper, we propose a novel construction of silicon nanowire （SiNW） negative-AND （NAND） logic gates on bendable plastic substrates and describe their electrical characteristics. The NAND logic gates with SiNW channels are capable of operating with a supply voltage as low as 0.8 V, with switching and standby power consumption of approximately 1.1 and 0.068 nW, respectively. Superior electrical characteristics of each SiNW transistor, including steep subthreshold slopes, high Ion/off ratio, and symmetrical threshold voltages, are the major factors that enable nanowatt-range power operation of the logic gates. Moreover, the mechanical bendability of the logic gates indicates that they have good and stable fatigue properties.展开更多
Soft molecule-based ferroelectrics with unique structural flexibility hold apromise for versatile applications of non-volatile memory, imaging and photovoltaicdevices. Except for few polymers (e.g., polyvinylidene flu...Soft molecule-based ferroelectrics with unique structural flexibility hold apromise for versatile applications of non-volatile memory, imaging and photovoltaicdevices. Except for few polymers (e.g., polyvinylidene fluoride, PVDF),it is challenging to exploit soft ferroelectric crystals toward free-standing flexiblephotoactive devices. We here report a multiaxial soft molecule-based ferroelectric,(n-PA)_(2)PbCl_(4) (1, where n-PA^(+)is n-pentylammonium), of whichspontaneous polarization can be reversibly switched in both crystal and powderforms. Strikingly, single crystals of 1 have unusual structural flexibility andbendability, achieving the self-standing bending with a bending radius of0.22 mm. Besides, the pyroelectric activities are also preserved for these singlecrystals after several bending cycles. Further, the bendable crystal-basedphotodetector of 1 allows broadband photoactivities via the photo-pyroelectriceffect, covering a wide range from 405 to 940 nm spectral region, breakingthrough the limit of optical absorption bandgap. As the first study of bendablefree-standing photo-pyroelectric detectors in ferroelectric crystals, our worksheds light on the assembly of flexible smart photoelectric devices.展开更多
Continuum robots,which are characterized by high length-to-diameter ratios and flexible structures,show great potential for various applications in confined and irregular environments.Due to the combination of motion ...Continuum robots,which are characterized by high length-to-diameter ratios and flexible structures,show great potential for various applications in confined and irregular environments.Due to the combination of motion modes,the existence of multiple solutions,and the presence of complex obstacle constraints,motion planning for these robots is highly challenging.To tackle the challenges of online and flexible operation for continuum robots,we propose a flexible head-following motion planning method that is suitable for scalable and bendable continuum robots.Firstly,we establish a piecewise constant curvature(PCC)kinematic model for scalable and bendable continuum robots.The article proposes an adaptive auxiliary points model and a method for updating key nodes in head-following motion to enhance the precise tracking capability for paths with different curvatures.Additionally,the article integrates the strategy for adjusting the posture of local joints of the robot into the head-following motion planning method,which is beneficial for achieving safe obstacle avoidance in local areas.The article concludes by presenting the results of multiple sets of motion simulation experiments and prototype experiments.The study demonstrates that the algorithm presented in this paper effectively navigates and adjusts posture to avoid obstacles,meeting the real-time demands of online operations.The average time for a single-step solution is 4.41×10^(-5) s,and the average tracking accuracy forcircular paths is 7.8928mm.展开更多
Elastic strain constitutes a decisive factor in determining the recoverable deformability of thermoelectric materials.Plastic deformation for microstructure engineering has been demonstrated as a viable approach to en...Elastic strain constitutes a decisive factor in determining the recoverable deformability of thermoelectric materials.Plastic deformation for microstructure engineering has been demonstrated as a viable approach to enhance the elastic strain.However,this approach is highly dependent on the material's plasticity,which is rather limited by the rigidity for the majority of inorganic semiconducting thermoelectric materials.Thermocouple materials,as metallic thermoelectric materials,possess a favorable plasticity,motivating this work to focus on the elastic bendability of a metallic thermoelectric generator that is composed of K-type thermocouple components,namely p-type Ni_(90)Cr_(10) and n-type Ni_(95)Al_(2)Mn_(2)Si.The cold-rolling process enables a large elastic modulus and a high yield strength,thanks to the texturized direction along<111>,and dense dislocations and refined grains,respectively,eventually resulting in a 400%increase in the elastic strain.Such superior elasticity ensures the preservation of the initial transport properties for the rolled films even after being bent 100000 times within a radius of~8 mm.A power output of~414μW is achieved in a ten-leg flexible thermoelectric device,suggesting its substantial potential for powering wearable electronics.展开更多
Thin-walled tube numerical control （NC） bending is a tri-nonlinear physical process with multi-defect and multi-die constraints. The clearance on each contact interface is the major factor to indicate the contact co...Thin-walled tube numerical control （NC） bending is a tri-nonlinear physical process with multi-defect and multi-die constraints. The clearance on each contact interface is the major factor to indicate the contact conditions. A three-dimensional-finite element （3D-FE） model is established to consider the realistic dynamic boundary conditions of multiple dies under ABAQUS/Explicit platform. Combined with experiment, numerical study on bending behavior and bendability under different clearance between tube and various dies is conducted in terms of wrinkling, wall thinning and cross section deformation. The results show that （1）with smaller clearance of tube-wiper die and tube-mandrel, the wrinkling can be restrained while the wall thinning It and cross-section deformation Id increase; while excessive small clearance blocks tube materials to flow past tangent point and causes piles up, the onset of wrinkling enhances It and Id. （2）Both It and Id decrease with smaller clearance of tube-pressure die; the wrinkling possibility rises with larger clearance on this interface if the mandrel’s freedom along Y-axis is opened; smaller clearance of tube-bend die prevents wrinkling while increases It, and the clearance on this interface has little effect on Id. （3）A modified Yoshida buckling test （YBT） is used to address the wrinkling mechanisms under normal constraints in tube bending： the smaller clearance may restrain wrinkling efficiently; the smaller wall thickness, the less critical clearance needed; the critical clearance for tube bending 38 mm×1 mm×57 mm （tube outer diameter×wall thickness×centerline bending radius） equals about 20% of initial wall thickness.展开更多
The microstructures and mechanical properties of the composite extruded AZ31/AZ31 and AZ31/4047 Al sheets were investigated and made a comparison to the conventional extruded AZ31 sheet.Owing to the introduced intense...The microstructures and mechanical properties of the composite extruded AZ31/AZ31 and AZ31/4047 Al sheets were investigated and made a comparison to the conventional extruded AZ31 sheet.Owing to the introduced intense shear deformation at the interface during the composite extrusion,grain refinement and tilted texture were detected in AZ31 layers of the AZ31/AZ31 and AZ31/4047 Al sheets,while the conventional extruded AZ31 sheet exhibited a relative coarse,inhomogeneous microstructure and strong basal texture.The compressiontension yield ratio was increased gradually from the AZ31 to the AZ31/AZ31 and AZ31/4047 Al sheets.Besides,the AZ31/4047 Al sheet could successfully accomplish the whole bending forming process at room temperature,while the AZ31 and AZ31/AZ31 sheets were both bend-formed to failure with significant cracks in the outer tensile region under the identical bending parameters.Moreover,under the same bending strain,both the outward offset degree of strain neutral layer and the sheet thickening were more serious in the AZ31/4047 Al composite sheet than those of the AZ31 and AZ31/AZ31 sheets.The foremost reason was the quite wide gap of material properties between Mg alloy AZ31 layer(tensile loading in the outer region)and Al 4047 layer(compressive loading in the inner region).展开更多
A significant enhancement of bendability was achieved by the introduction of bimodal microstructure for AZ31B alloy sheets via pre-compression and subsequent annealing(PCA)process.This combined treatment led to the c-...A significant enhancement of bendability was achieved by the introduction of bimodal microstructure for AZ31B alloy sheets via pre-compression and subsequent annealing(PCA)process.This combined treatment led to the c-axis of the extracted samples that were inclined by 30°to the rolling direction(30°sample)further shifting toward the rolling direction(RD)and resulting in a higher Schmid factor(SF)value of basal slip under the RD tensile stress.Furthermore,the bimodal microstructure that was introduced by the PCA process broke the damage bands(DBs)in the initial hot rolled AZ31B alloy sheets and gave rise to a more uniform strain distribution in the outer tension region of the bending samples,in which the tensile deformation was accommodated by the equally distributed{101^(-)2}tension twinning and basal slip.Consequently,the bimodal microstructure,shifted basal texture and the modification of DBs were responsible for the significant enhancement in the bendability of the AZ31 alloys.展开更多
Flexible solar cells are important photovoltaics(PV)technologies due to the reduced processing temperature,less material consumption and mechanical flexibility,thus they have promising applications for portable device...Flexible solar cells are important photovoltaics(PV)technologies due to the reduced processing temperature,less material consumption and mechanical flexibility,thus they have promising applications for portable devices and building-integrated applications.However,the efficient harvesting of photons is the core hindrance towards efficient,flexible PV.Light management by nanostructures and nanomaterials has opened new pathways for sufficient solar energy harvesting.Nanostructures on top surfaces provide an efficient pathway for the propagation of light.Aside from suppressing incident light reflection,micro-structured back-reflectors reduce transmission via multiple reflections.Nanostructures themselves can be the absorber layer.Photovoltaics based on high-crystallinity nanostructured light absorbers demonstrate enhanced power conversion efficiency(PCE)and excellent mechanical flexibility.To acquire a deep understanding of the impacts of nanostructures,herein,a concise overview of the recent development in the design and application of nanostructures and nanomaterials for photovoltaics is summarized.展开更多
A new 980 MPa advanced high-strength steel(AHSS) with excellent bendability and flangeability has been studied and industrially produced, typical of tensile strength, fractured elongation, and hole expansion ratio(HER...A new 980 MPa advanced high-strength steel(AHSS) with excellent bendability and flangeability has been studied and industrially produced, typical of tensile strength, fractured elongation, and hole expansion ratio(HER) exceeding 980 MPa, 10%,and 30%,respectively.The 90° V-type bending perpendicular to the rolling direction can satisfy the R/t=1.0 requirement, indicating excellent bendability.Systematic evaluations of industrial trial-produced 980 MPa hot-rolled AHSS have been conducted, including microstructure, tensile properties in three directions, HER,bendability, fatigue limit strength, and forming limit.The microstructure of the newly developed 980 MPa AHSS primarily consists of fine bainite and a small amount of martensite-austenite constituent.The practical yield and tensile strength are higher than 800 and 980 MPa, respectively, with typical elongation of 13% and HER of around 40%.The good combination of the newly developed 980 MPa AHSS is primarily attributed to the fine bainitic microstructure, resulting in excellent flangeability and bendability.In addition, the newly developed 980 MPa AHSS has good fatigue and forming properties, making it suitable for the production of chassis and suspension components.展开更多
A surface nanocrystalline was fabricated by ultrasonic shot peening(USSP)treatment at AZ31 Mg alloy.The effect of nanocrystalline thickness and its placed side(external or internal)on the bendability was studied by a ...A surface nanocrystalline was fabricated by ultrasonic shot peening(USSP)treatment at AZ31 Mg alloy.The effect of nanocrystalline thickness and its placed side(external or internal)on the bendability was studied by a V-bending test.Three durations,5,10,and 15 min,were applied to form the surface nanocrystalline with thicknesses of 51,79,and 145μm,respectively.Two-side treatment led to a similar bendability as that of as-received.One-side internal treatment for 5 min resulted in an improved bendability while the improvement was limited and degenerated for longer treatment.The improvement was related to the drawing back of the neutral axis.The one-side external treatment also improved the bendability,and the improvement was due to the redistribution of strain and stress during bending.With nanocrystalline at external side,it resulted in a larger stress but a smaller strain at the convex,which prevented the happening of crack during bending.展开更多
As cold-formed steel has the highest strength-to-weight ratio of any material,ultra-high strength martensitic steel is attracting great interest from global car manufacturers. This paper explores the effects of the qu...As cold-formed steel has the highest strength-to-weight ratio of any material,ultra-high strength martensitic steel is attracting great interest from global car manufacturers. This paper explores the effects of the quenching and over-aging temperatures on the strength and cold bendability of C-Mn-Si martensitic steel. Due to its high carbon content,water-quenched C-Mn-Si martensitic steel has high hardenability and can obtain ultra-high tensile strength and uniform martensitic morphology when the water-quenching temperature is higher than 710 ℃.Increasing the over-aging temperature of this experimental steel decreases its tensile strength,increases the total elongation,and first increases then decreases the yield point until reaching a peak at 180 ℃. Besides,when increasing the over-aging temperature,the bendability of this experimental steel initially improves and then decreases,and reaches its optimal bendability at an over-aging temperature of 180 ℃. Based on SEM characterization and a microhardness distribution analysis,the over-aging temperatures were found to affect the size of the carbides and differences in the microhardness of the experimental steel. Therefore,they have significant influence on bendability.展开更多
Extensive researches have elucidated the pronounced benefits of gradient microstructures for the me-chanical properties of metallic materials.However,the ramifications of gradient microstructures on formability,partic...Extensive researches have elucidated the pronounced benefits of gradient microstructures for the me-chanical properties of metallic materials.However,the ramifications of gradient microstructures on formability,particularly regarding their effects on bendability,remain inadequately understood.In this work,the effects of gradient microstructure on the bendability of AZ31 Mg alloy sheet are systematically investigated by comparing the microstructure evolution and strain distribution in the sheets with uni-form microstructure(grain size=12.8 μm and 91.3 μm)and gradient microstructure(grain size=11.5-75.4 μm).The results show that the bendability of the sheet with gradient microstructure is significantly improved when the fine grains(FGs)are placed at the outer side(TBE-FG sample)and the bendability is increased by 93.1%compared to the sample with fine and uniform microstructure(CE-FG sample).With coarse grains(CGs)placed at the inner side,the strain at the compressive region of the TBE-FG sample is higher than its counterparts,while the tensile strain at the extended region is lowest among the four samples.Quasi-in-situ bending experiments reveal that the CGs at the inner side of the TBE-FG sample undergo more twinning.Moreover,the increment of residual dislocation density at the outer side of the TBE-FG sample is lower than those of other samples,which extends the bending potential.This work provides a novel perspective to improve the bendability of the Mg alloy sheet.展开更多
基金CNPq, Govt. of Brazil for providing financial support under the scheme of Science without Border to carry out this research work
文摘Carbon fiber yarns（CFY） are promising as a new type of flexible building blocks for the construction of flexible architectures for the energy storage applications. The main hurdle with CFY is how to make them high energy and power capable by using economically and environmentally viable materials. Here,we report reduced graphene oxide（r GO） and Prussian blue（PB） coated CFY, derived from a facile electrochemical process at room temperature for supercapacitor electrodes. The PB coated CFY and r GO coated CFY electrodes exhibit the excellent gravimetric capacitance of 339 F/g and 160.2 F/g, respectively, in aqueous KCl electrolyte in three-electrode cell configuration. When we coupled these electrodes inside the flexible plastic tube and separated by the electrolyte wet filter paper in order to construct flexible architecture, the resulting device delivers excellent specific energy of 52.1 Wh/kg and 26.5 Wh/kg with offering specific power of 3100 W/kg and 14400 W/kg respectively, under a wide operating potential of1.8 V with excellent rate capability. The device shows high tolerance towards bending, and retained its efficiency to the capacitance after being bent at an angle of 360° for 200 bending cycles.
基金Supported by the National Basic Research Program of China under Grant No 2012CB619200the National Natural Science Foundation of China under Grant Nos 61290304,11074265 and 11174307+1 种基金the Natural Science Foundation of Shanghai under Grant No 16ZR1441200the Frontier Science Research Project(Key Programs)of Chinese Academy of Sciences under Grant No QYZDJ-SSW-SLH018
文摘Recently, great efforts have been made in the fabrication of arbitrary warped devices to satisfy the requirement of wearable and lightweight electronic products. Direct growth of high crystalline quality films on flexible substrates is the most desirable method to fabricate flexible devices owing to the advantage of simple and compatible preparation technology with current semiconductor devices, while it is a very challenging work, and usually amorphous, polycrystalline or discontinuous single crystalline films are achieved. Here we demonstrate the direct growth of high-quality Bi2 Te3 single crystalline films on flexible polyimide substrates by the modified hot wall epitaxy technique. Experimental results reveal that adjacent crystallites are coherently coalesced to form a continuous film, although amounts of disoriented crystallites are generated due to fast growth rate. By inserting a quartz filter into the growth tube, the number density of disoriented crystallites is effectively reduced owing to the improved spiral interaction. Furthermore, flexible Bi2 Te3 photoconductors are fabricated and exhibit strong near-infrared photoconductive response under different degrees of bending, which also confirms the obtained fexible films suitable for electronic applications.
基金supported by the Technology InnovationProgram(20023588)funded by the Ministry ofTrade,Industry,and Energy(MOTIE,Korea)the LG Display-POSTECH Incubation collaboration PJT and BK21 FOUR program,Educational Institute for Intelligent Information Integration of the National Research Foundation of Korea(NRF,Korea)。
文摘Flexible electronics demand multifunctional human-machine interfaces(HMIs)and organic user interfaces(OUIs).Existing deformable displays often rely on mechanical wires or hinges,limiting their thinness and flexibility.Incorporating sound features typically requires extra components,complicating design.In this study,we developed a lightweight,multifunctional display with a multishape bendable design and integrated sound capabilities.Using asymmetrical strain engineering on poly(vinylidene fluoride)(PVDF),we achieved bidirectional and complex deformations through electrical signals,eliminating the need for mechanical hinges.The PVDF actuator enables simultaneous sound emission and intricate shape transformations through rapid actuation and vibration.This design maintains the thinness and flexibility of organic light-emitting diode(OLED)technology.By controlling strain through PVDF polarization and applied electric field,we realized varied shape transformations and integrated these functions into a practical 6-inch OLED display.This approach enhances the functionality of flexible displays,expanding possibilities for future applications in flexible electronics.
基金supported by the National Key R&D Program of China(2024YFA1509300)the National Natural Science Foundation of China(22175082 and 91856114).
文摘Phase transition materials,which enable the switching of physical properties like second harmonic generation(SHG),have attracted great interest due to their wide applications,such as in sensors.However,although significant progress has been made in crystalline SHG switching phase transition materials,these materials typically show poor mechanical flexibility,hindering their applications in flexible wearable devices.Herein,for the first time,we reported a bendable photoluminescent molecular crystal(R)-octan-2-yl(E)-4-((4-(hexadecyloxy)-2-hydroxybenzylidene)amino)benzoate(R-EHAB),which shows a phase transition at around 320 K,accompanied by obvious SHG switching between high-SHG and low-SHG states.Significantly,R-EHAB demonstrates a low elastic modulus of 3.03 GPa,which is much lower than that of most molecular phase transition crystals.This enables its crystals to be easily bent into a semicircular shape and remain unchanged after bending-recovery cycles.To our knowledge,R-EHAB is the first bendable molecular crystal with a phase transition accompanied by SHG switching.This work would inspire the further exploration of more bendable phase transition crystals for potential application in next-generation functional devices.
文摘In this study, we propose a novel combination of tunneling field-effect transistors （TFETs） with asymmetrically doped p^＋-i-n^＋ silicon nanowire （SiNW） channels on a bendable substrate. The combination of two n-channel SiNW-TFETs （NWTFETs） in parallel and two p-channel NWTFETs in series operates as a two-input NOR logic gate. The component NWTFETs with the n- and p-channels exhibit subthreshold swings （SSs） of 69 and 53 mV·dec^-1, respectively, and the on/off current ratios are -106. The NOR logic operation is sustainable and reproducible for up to 1,000 bending cycles with a narrow transition width of -0.26 V. The mechanical bendability of the bendable NWTFETs shows that they are stable and have good fatigue properties. To the best of our knowledge, this is the first study on the electrical and mechanical characteristics of a bendable NOR logic gate composed of NWTFETs.
文摘In this paper, we demonstrate the low-power functionality of silicon nanowire （SiNW）-assembled inverters on bendable plastics. Our bendable inverters are capable of operating at supply voltages as low as 0.8 V with a switching （or standby） power consumption of -0.2 nW （or -6.6 pW）. The low-power inverting operation with a voltage gain of -18 is attributable to the near-ideal characteristics of the component transistors that have selectively thinned SiNW channels and exhibit low, symmetrical threshold voltages of 0.40 and -0.39 V and low subthreshold swing values of 81 and 65 mV/dec. Moreover, mechanical bendability reveals that the inverting operation has good, stable fatigue properties.
文摘In this study, we propose complementary metal-oxide-semiconductor （CMOS） NOR logic gates consisting of silicon nanowire （NW） arrays on bendable substrates. A circuit consisting of two p-channel NW field-effect transistors （NWFETs） in series and two n-channel NWFETs in parallel is constructed to operate a two- input CMOS NOR logic gate. The NOR logic gates operate at a low supply voltage of 1 V with a rail-to-rail logic swing and a high voltage gain of approximately -3.0. The exact NOR logic functionality is achieved owing to the superior electrical characteristics of the well-aligned p- and n-NWFETs, which are obtained using conventional Si-based CMOS technology. Moreover, the NOR logic gates exhibit stable characteristics and have good mechanical properties. The proposed bendable NW CMOS NOR logic gates are promising building blocks for future bendable integrated electronics.
文摘In this study, we demonstrate the performance of silicon nanowire （SiNW） n-metal oxide semiconductor （MOS） and p-MOS ratioed inverters that are fabricated on bendable substrates. The electrical characteristics of the fabricated devices can be controlled by adjusting the load voltage. The logic swings of the n- and p-MOS ratioed inverters at a low supply voltage of 1V are 80% and 96%, respectively. The output voltage level of the p-MOS ratioed inverter is close to rail-to-rail operation. The device also exhibits stable characteristics with good fatigue properties. Our bendable SiNW ratioed inverters show promise as a candidate building block for future bendable electronics.
文摘In this paper, we propose a novel construction of silicon nanowire （SiNW） negative-AND （NAND） logic gates on bendable plastic substrates and describe their electrical characteristics. The NAND logic gates with SiNW channels are capable of operating with a supply voltage as low as 0.8 V, with switching and standby power consumption of approximately 1.1 and 0.068 nW, respectively. Superior electrical characteristics of each SiNW transistor, including steep subthreshold slopes, high Ion/off ratio, and symmetrical threshold voltages, are the major factors that enable nanowatt-range power operation of the logic gates. Moreover, the mechanical bendability of the logic gates indicates that they have good and stable fatigue properties.
基金National Natural Science Foundation of China,Grant/Award Numbers:22125110,U23A2094,22205233,22193042,21921001,U21A2069,22305248Natural Science Foundation of Fujian Province,Grant/Award Numbers:2023J02028,2023J01235+2 种基金Key Research Program of Frontier Sciences of Chinese Academy of Sciences,Grant/Award Number:ZDBSLY-SLH024Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China,Grant/Award Number:2021ZR126China Postdoctoral Science Foundation,Grant/Award Number:2023M733497。
文摘Soft molecule-based ferroelectrics with unique structural flexibility hold apromise for versatile applications of non-volatile memory, imaging and photovoltaicdevices. Except for few polymers (e.g., polyvinylidene fluoride, PVDF),it is challenging to exploit soft ferroelectric crystals toward free-standing flexiblephotoactive devices. We here report a multiaxial soft molecule-based ferroelectric,(n-PA)_(2)PbCl_(4) (1, where n-PA^(+)is n-pentylammonium), of whichspontaneous polarization can be reversibly switched in both crystal and powderforms. Strikingly, single crystals of 1 have unusual structural flexibility andbendability, achieving the self-standing bending with a bending radius of0.22 mm. Besides, the pyroelectric activities are also preserved for these singlecrystals after several bending cycles. Further, the bendable crystal-basedphotodetector of 1 allows broadband photoactivities via the photo-pyroelectriceffect, covering a wide range from 405 to 940 nm spectral region, breakingthrough the limit of optical absorption bandgap. As the first study of bendablefree-standing photo-pyroelectric detectors in ferroelectric crystals, our worksheds light on the assembly of flexible smart photoelectric devices.
基金supported in part by the Fundamental Research Funds for the Central Universities,China(DUT22GF301).
文摘Continuum robots,which are characterized by high length-to-diameter ratios and flexible structures,show great potential for various applications in confined and irregular environments.Due to the combination of motion modes,the existence of multiple solutions,and the presence of complex obstacle constraints,motion planning for these robots is highly challenging.To tackle the challenges of online and flexible operation for continuum robots,we propose a flexible head-following motion planning method that is suitable for scalable and bendable continuum robots.Firstly,we establish a piecewise constant curvature(PCC)kinematic model for scalable and bendable continuum robots.The article proposes an adaptive auxiliary points model and a method for updating key nodes in head-following motion to enhance the precise tracking capability for paths with different curvatures.Additionally,the article integrates the strategy for adjusting the posture of local joints of the robot into the head-following motion planning method,which is beneficial for achieving safe obstacle avoidance in local areas.The article concludes by presenting the results of multiple sets of motion simulation experiments and prototype experiments.The study demonstrates that the algorithm presented in this paper effectively navigates and adjusts posture to avoid obstacles,meeting the real-time demands of online operations.The average time for a single-step solution is 4.41×10^(-5) s,and the average tracking accuracy forcircular paths is 7.8928mm.
基金supported by the National Key Research and Development Program of China(2023YFB3809400)the National Natural Science Foundation of China(Grant nos.T2125008,92163203,and 52371234)+1 种基金the Hong Kong,Macao,and Taiwan Science and Technology Cooperation Project for Science and Technology Innovation Plan of Shanghai(23520760600)the Fundamental Research Funds for the Central Universities.
文摘Elastic strain constitutes a decisive factor in determining the recoverable deformability of thermoelectric materials.Plastic deformation for microstructure engineering has been demonstrated as a viable approach to enhance the elastic strain.However,this approach is highly dependent on the material's plasticity,which is rather limited by the rigidity for the majority of inorganic semiconducting thermoelectric materials.Thermocouple materials,as metallic thermoelectric materials,possess a favorable plasticity,motivating this work to focus on the elastic bendability of a metallic thermoelectric generator that is composed of K-type thermocouple components,namely p-type Ni_(90)Cr_(10) and n-type Ni_(95)Al_(2)Mn_(2)Si.The cold-rolling process enables a large elastic modulus and a high yield strength,thanks to the texturized direction along<111>,and dense dislocations and refined grains,respectively,eventually resulting in a 400%increase in the elastic strain.Such superior elasticity ensures the preservation of the initial transport properties for the rolled films even after being bent 100000 times within a radius of~8 mm.A power output of~414μW is achieved in a ten-leg flexible thermoelectric device,suggesting its substantial potential for powering wearable electronics.
基金National Natural Science Foundation of China (59975076, 50905144)State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology (09-10)+1 种基金NPU Foundation for Fundamental Research (JC201028)Fund of the State Key Laboratory of Solidification Process-ing in NWPU
文摘Thin-walled tube numerical control （NC） bending is a tri-nonlinear physical process with multi-defect and multi-die constraints. The clearance on each contact interface is the major factor to indicate the contact conditions. A three-dimensional-finite element （3D-FE） model is established to consider the realistic dynamic boundary conditions of multiple dies under ABAQUS/Explicit platform. Combined with experiment, numerical study on bending behavior and bendability under different clearance between tube and various dies is conducted in terms of wrinkling, wall thinning and cross section deformation. The results show that （1）with smaller clearance of tube-wiper die and tube-mandrel, the wrinkling can be restrained while the wall thinning It and cross-section deformation Id increase; while excessive small clearance blocks tube materials to flow past tangent point and causes piles up, the onset of wrinkling enhances It and Id. （2）Both It and Id decrease with smaller clearance of tube-pressure die; the wrinkling possibility rises with larger clearance on this interface if the mandrel’s freedom along Y-axis is opened; smaller clearance of tube-bend die prevents wrinkling while increases It, and the clearance on this interface has little effect on Id. （3）A modified Yoshida buckling test （YBT） is used to address the wrinkling mechanisms under normal constraints in tube bending： the smaller clearance may restrain wrinkling efficiently; the smaller wall thickness, the less critical clearance needed; the critical clearance for tube bending 38 mm×1 mm×57 mm （tube outer diameter×wall thickness×centerline bending radius） equals about 20% of initial wall thickness.
基金The authors are grateful for the financial supports from the National Key Research and Development Program of China(2016YFB0301104 and 2016YFB0101700)Chongqing Science and Technology Commission(cstc2017zdcy-zdzxX0006,cstc2017jcyjAX0012,cstc2018jcyjAX0472)+3 种基金National Natural Science Foundation of China(51531002 and U1764253)Chongqing Scientific&Technological Talents Program(KJXX2017002)China Postdoctoral Science Foundation(2018T110948)Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN201801306).
文摘The microstructures and mechanical properties of the composite extruded AZ31/AZ31 and AZ31/4047 Al sheets were investigated and made a comparison to the conventional extruded AZ31 sheet.Owing to the introduced intense shear deformation at the interface during the composite extrusion,grain refinement and tilted texture were detected in AZ31 layers of the AZ31/AZ31 and AZ31/4047 Al sheets,while the conventional extruded AZ31 sheet exhibited a relative coarse,inhomogeneous microstructure and strong basal texture.The compressiontension yield ratio was increased gradually from the AZ31 to the AZ31/AZ31 and AZ31/4047 Al sheets.Besides,the AZ31/4047 Al sheet could successfully accomplish the whole bending forming process at room temperature,while the AZ31 and AZ31/AZ31 sheets were both bend-formed to failure with significant cracks in the outer tensile region under the identical bending parameters.Moreover,under the same bending strain,both the outward offset degree of strain neutral layer and the sheet thickening were more serious in the AZ31/4047 Al composite sheet than those of the AZ31 and AZ31/AZ31 sheets.The foremost reason was the quite wide gap of material properties between Mg alloy AZ31 layer(tensile loading in the outer region)and Al 4047 layer(compressive loading in the inner region).
基金financial supports from the National Natural Science Foundation of China (Nos.U1764253,51971044,U1910213,52001037,and U207601)Qinghai Scientific&Technological Program (No.2018-GX-A1)Natural Science Foundation of Chongqing (No.c stc2019jcyj-msxmX 0234)
文摘A significant enhancement of bendability was achieved by the introduction of bimodal microstructure for AZ31B alloy sheets via pre-compression and subsequent annealing(PCA)process.This combined treatment led to the c-axis of the extracted samples that were inclined by 30°to the rolling direction(30°sample)further shifting toward the rolling direction(RD)and resulting in a higher Schmid factor(SF)value of basal slip under the RD tensile stress.Furthermore,the bimodal microstructure that was introduced by the PCA process broke the damage bands(DBs)in the initial hot rolled AZ31B alloy sheets and gave rise to a more uniform strain distribution in the outer tension region of the bending samples,in which the tensile deformation was accommodated by the equally distributed{101^(-)2}tension twinning and basal slip.Consequently,the bimodal microstructure,shifted basal texture and the modification of DBs were responsible for the significant enhancement in the bendability of the AZ31 alloys.
基金the National Natural Science Foundation of China(Project No.51672231)the Science and Technology Plan of Shenzhen(Project Nos.JCYJ20170818114107730,JCYJ20180306174923335)+2 种基金the General Research Fund(Project Nos.16309018,16214619)from the Hong Kong Research Grant Council.Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory(Project No.2020B1212030010)HKUST Fund of Nanhai(Grant No.FSNH-18FYTRI01)the Center for 1D/2D Quantum Materials and the State Key Laboratory of Advanced Displays and Optoelectronics Technologies at HKUST and Foshan Innovative and Entrepreneurial Research Team Program(2018IT100031).
文摘Flexible solar cells are important photovoltaics(PV)technologies due to the reduced processing temperature,less material consumption and mechanical flexibility,thus they have promising applications for portable devices and building-integrated applications.However,the efficient harvesting of photons is the core hindrance towards efficient,flexible PV.Light management by nanostructures and nanomaterials has opened new pathways for sufficient solar energy harvesting.Nanostructures on top surfaces provide an efficient pathway for the propagation of light.Aside from suppressing incident light reflection,micro-structured back-reflectors reduce transmission via multiple reflections.Nanostructures themselves can be the absorber layer.Photovoltaics based on high-crystallinity nanostructured light absorbers demonstrate enhanced power conversion efficiency(PCE)and excellent mechanical flexibility.To acquire a deep understanding of the impacts of nanostructures,herein,a concise overview of the recent development in the design and application of nanostructures and nanomaterials for photovoltaics is summarized.
文摘A new 980 MPa advanced high-strength steel(AHSS) with excellent bendability and flangeability has been studied and industrially produced, typical of tensile strength, fractured elongation, and hole expansion ratio(HER) exceeding 980 MPa, 10%,and 30%,respectively.The 90° V-type bending perpendicular to the rolling direction can satisfy the R/t=1.0 requirement, indicating excellent bendability.Systematic evaluations of industrial trial-produced 980 MPa hot-rolled AHSS have been conducted, including microstructure, tensile properties in three directions, HER,bendability, fatigue limit strength, and forming limit.The microstructure of the newly developed 980 MPa AHSS primarily consists of fine bainite and a small amount of martensite-austenite constituent.The practical yield and tensile strength are higher than 800 and 980 MPa, respectively, with typical elongation of 13% and HER of around 40%.The good combination of the newly developed 980 MPa AHSS is primarily attributed to the fine bainitic microstructure, resulting in excellent flangeability and bendability.In addition, the newly developed 980 MPa AHSS has good fatigue and forming properties, making it suitable for the production of chassis and suspension components.
基金financially supported by the Natural Science Basic Research Program of Shaanxi,China(No.2021JQ-250)the Fundamental Research Funds for the Central Universities(No.300102220301)。
文摘A surface nanocrystalline was fabricated by ultrasonic shot peening(USSP)treatment at AZ31 Mg alloy.The effect of nanocrystalline thickness and its placed side(external or internal)on the bendability was studied by a V-bending test.Three durations,5,10,and 15 min,were applied to form the surface nanocrystalline with thicknesses of 51,79,and 145μm,respectively.Two-side treatment led to a similar bendability as that of as-received.One-side internal treatment for 5 min resulted in an improved bendability while the improvement was limited and degenerated for longer treatment.The improvement was related to the drawing back of the neutral axis.The one-side external treatment also improved the bendability,and the improvement was due to the redistribution of strain and stress during bending.With nanocrystalline at external side,it resulted in a larger stress but a smaller strain at the convex,which prevented the happening of crack during bending.
文摘As cold-formed steel has the highest strength-to-weight ratio of any material,ultra-high strength martensitic steel is attracting great interest from global car manufacturers. This paper explores the effects of the quenching and over-aging temperatures on the strength and cold bendability of C-Mn-Si martensitic steel. Due to its high carbon content,water-quenched C-Mn-Si martensitic steel has high hardenability and can obtain ultra-high tensile strength and uniform martensitic morphology when the water-quenching temperature is higher than 710 ℃.Increasing the over-aging temperature of this experimental steel decreases its tensile strength,increases the total elongation,and first increases then decreases the yield point until reaching a peak at 180 ℃. Besides,when increasing the over-aging temperature,the bendability of this experimental steel initially improves and then decreases,and reaches its optimal bendability at an over-aging temperature of 180 ℃. Based on SEM characterization and a microhardness distribution analysis,the over-aging temperatures were found to affect the size of the carbides and differences in the microhardness of the experimental steel. Therefore,they have significant influence on bendability.
基金National Key Research and Development Program of China(Project No.2021YFB3701000)financial support of the National Natural Science Foundation of China(Project Nos.52101124,U21A2048)Independent Research Project of State Key Laboratory of Mechanical Transmissions(Project No.SKLMT-ZZKT-2022M12).
文摘Extensive researches have elucidated the pronounced benefits of gradient microstructures for the me-chanical properties of metallic materials.However,the ramifications of gradient microstructures on formability,particularly regarding their effects on bendability,remain inadequately understood.In this work,the effects of gradient microstructure on the bendability of AZ31 Mg alloy sheet are systematically investigated by comparing the microstructure evolution and strain distribution in the sheets with uni-form microstructure(grain size=12.8 μm and 91.3 μm)and gradient microstructure(grain size=11.5-75.4 μm).The results show that the bendability of the sheet with gradient microstructure is significantly improved when the fine grains(FGs)are placed at the outer side(TBE-FG sample)and the bendability is increased by 93.1%compared to the sample with fine and uniform microstructure(CE-FG sample).With coarse grains(CGs)placed at the inner side,the strain at the compressive region of the TBE-FG sample is higher than its counterparts,while the tensile strain at the extended region is lowest among the four samples.Quasi-in-situ bending experiments reveal that the CGs at the inner side of the TBE-FG sample undergo more twinning.Moreover,the increment of residual dislocation density at the outer side of the TBE-FG sample is lower than those of other samples,which extends the bending potential.This work provides a novel perspective to improve the bendability of the Mg alloy sheet.
