Disposable devices designed for single and/or multiple reliable measurements over a short duration have attracted considerable interest recently. However, these devices often use non-recyclable and non-biodegradable m...Disposable devices designed for single and/or multiple reliable measurements over a short duration have attracted considerable interest recently. However, these devices often use non-recyclable and non-biodegradable materials and wasteful fabrication methods. Herein, we present ZnO nanowires(NWs) based degradable high-performance UV photodetectors(PDs) on flexible chitosan substrate. Systematic investigations reveal the presented device exhibits excellent photo response, including high responsivity(55 A/W), superior specific detectivity(4×10^(14) jones), and the highest gain(8.5×10~(10)) among the reported state of the art biodegradable PDs. Further, the presented PDs display excellent mechanical flexibility under wide range of bending conditions and thermal stability in the measured temperature range(5–50 ℃).The biodegradability studies performed on the device, in both deionized(DI) water(pH≈6) and PBS solution(pH=7.4),show fast degradability in DI water(20 mins) as compared to PBS(48 h). These results show the potential the presented approach holds for green and cost-effective fabrication of wearable, and disposable sensing systems with reduced adverse environmental impact.展开更多
The mass production of primed electronics can be achieved by roll-to-roll(R2R) printing system, so highly accurate web tension is required that can minimize the register error and keep the thickness and roughness of...The mass production of primed electronics can be achieved by roll-to-roll(R2R) printing system, so highly accurate web tension is required that can minimize the register error and keep the thickness and roughness of printed devices in limits. The web tension of a R2R system is regulated by the use of integrated load cells and active dancer system for printed electronics applications using decentralized multi-input-single-output(MISO) regularized variable learning rate backpropagation artificial neural networks. The active dancer system is used before printing system to reduce disturbances in the web tension of process span. The classical PID control result in tension spikes with the change in roll diameter of winder and unwinder rolls. The presence of dancer in R2R system shows that improved web tension control in printing span and the web tension can be enhanced from 3.75 N to 4.75 N. The overshoot of system is less than ±2.5 N and steady state error is within ± 1 N where load cells have a signal noise of ±0.7 N. The integration of load cells and active dancer with self-adapting neural network control provide a solution to the web tension control of multispan roll-to-roll system.展开更多
Metal oxide thin-films transistors(TFTs)produced from solution-based printing techniques can lead to large-area electronics with low cost.However,the performance of current printed devices is inferior to those from va...Metal oxide thin-films transistors(TFTs)produced from solution-based printing techniques can lead to large-area electronics with low cost.However,the performance of current printed devices is inferior to those from vacuum-based methods due to poor film uniformity induced by the“coffeering”effect.Here,we report a novel approach to print highperformance indium tin oxide(ITO)-based TFTs and logic inverters by taking advantage of such notorious effect.ITO has high electrical conductivity and is generally used as an electrode material.However,by reducing the film thickness down to nanometers scale,the carrier concentration of ITO can be effectively reduced to enable new applications as active channels in transistors.The ultrathin(~10-nm-thick)ITO film in the center of the coffee-ring worked as semiconducting channels,while the thick ITO ridges(>18-nm-thick)served as the contact electrodes.The fully inkjet-printed ITO TFTs exhibited a high saturation mobility of 34.9 cm2 V^(−1) s^(−1) and a low subthreshold swing of 105 mV dec^(−1).In addition,the devices exhibited excellent electrical stability under positive bias illumination stress(PBIS,ΔV_(th)=0.31 V)and negative bias illuminaiton stress(NBIS,ΔV_(th)=−0.29 V)after 10,000 s voltage bias tests.More remarkably,fully printed n-type metal–oxide–semiconductor(NMOS)inverter based on ITO TFTs exhibited an extremely high gain of 181 at a low-supply voltage of 3 V,promising for advanced electronics applications.展开更多
In order to overcome the shortcomings of low-cost anti-oxidation conductive ink and its preparation method in the field of printing electronics, core-shell coated Cu@Ag nanoparticles were used to prepare conductive in...In order to overcome the shortcomings of low-cost anti-oxidation conductive ink and its preparation method in the field of printing electronics, core-shell coated Cu@Ag nanoparticles were used to prepare conductive ink, and a printed circuit was obtained by inkjet printing. Copper nanoparticles were prepared by a chemical reduction method and then coated with Cu@Ag particles by a copper-based self-catalytic reaction. Conductive ink was prepared by ball milling and dispersion and printed on PI film to form a conductive coating. After characterization and analysis, the particle size and dispersion of the obtained Cu@Ag meet the requirements and can be stored stably under normal atmospheric conditions. The resistivity of the conductive film sintered at 300˚C is only 10.6 μΩ<span style="font-size:10.0pt;font-family:"">∙</span>cm.展开更多
Nitrate is the primary water-soluble macronutrient essential for plant growth that is converted from excess fish feeds,fish effluents,and degrading biomaterials on the aquaponic pond floor,and when aquacultural malpra...Nitrate is the primary water-soluble macronutrient essential for plant growth that is converted from excess fish feeds,fish effluents,and degrading biomaterials on the aquaponic pond floor,and when aquacultural malpractices occur,large amounts of it retain in the water system causing increase rate in eutrophication and toxifies fish and aquaculture plants.Recent nitrate sensor prototypes still require performing the additional steps of water sample deionization and dilution and were constructed with expensive materials.In response to the challenge of sensor enhancement and aquaponic water quality monitoring,this study developed sensitive,repeatable,and reproducible screen-printed graphite electrodes on polyvinyl chloride and parchment paper substrates with silver as electrode material and 60:40 graphite powder:nail polish formulated conductive ink for electrical traces,integrated with 9-gene genetic expression model as a function of peak anodic current and electrochemical test time for nitrate concentration prediction that is embedded into low-power Arduino ESP32 for in situ nitrate sensing in aquaponic pond water.Five SPE electrical traces were designed on the two types of substrates.Scanning electron microscopy with energy dispersive X-ray confirmed the electrode surface morphology.Electrochemical cyclic voltammetry using 10 to 100 mg/L KNO3 and water from three-depth regions of the actual pond established the electrochemical test time(10.5 s)and electrode potential(0.135 V)protocol necessary to produce peak current that corresponds to the strength of nitrate ions during redox.The findings from in situ testing revealed that the proposed sensors have strong linear predictions(R2=0.968 MSE=1.659 for nSPEv and R2=0.966 MSE=4.697 for nSPEp)in the range of 10 to 100 mg/L and best detection limit of 3.15μg/L,which are comparable to other sensors of more complex construction.The developed three-electrode electrochemical nitrate sensor confirms that it is reliable for both biosensing in controlled solutions and in situ aquaponic pond water systems.展开更多
Printed circuit boards(PCBs)are representative composite materials,and their high-quality drilling machining remains a persistent challenge in the industry.The finishing of the cutting edge of a microdrill is crucial ...Printed circuit boards(PCBs)are representative composite materials,and their high-quality drilling machining remains a persistent challenge in the industry.The finishing of the cutting edge of a microdrill is crucial to drill performance in machining fine-quality holes with a prolonged tool life.The miniature size involving submicron scale geometric dimensions,a complex flute shape,and low fracture toughness makes the cutting edge of microdrills susceptible to breakage and has been the primary limiting factor in edge preparation for microdrills.In this study,a newly developed cutting edge preparation method for microdrills was tested experimentally on electronic printed circuit boards.The proposed method,namely,shear thickening polishing,limited the cutting edge burrs and chipping on the cutting edge,and this in turn transformed the cutting edge’s radius from being sharp to smooth.Moreover,the edge–edge radius could be regulated by adjusting the processing time.PCB drilling experiments were conducted to investigate the influence of different cutting edge radii on wear,hole position accuracy,nail head value,and hole wall roughness.The proposed approach showed 20%enhancement in hole position accuracy,33%reduction in the nail head value,and 19%reduction in hole wall roughness compared with the original microdrill.However,a threshold is needed;without it,excessive shear thickening polishing will result in a blunt edge,which may accelerate the wear of the microdrill.Wear was identified as the primary factor that reduced hole quality.The study indicates that in printed circuit board machining,microdrills should effectively eliminate grinding defects and maintain the sharpness of the cutting edge as much as possible to obtain excellent drilling quality.Overall,shear thickening polishing is a promising method for cutting edge preparation of microdrills.Further research and optimization can lead to additional improvements in microdrill performance and contribute to the continued advancement of printed circuit board manufacturing.展开更多
Liquid metal based printed electronics was a newly emerging frontier in recent years. However, restricted by the single silver-white appearance of the liquid metal(LM), the colors of currently available printed electr...Liquid metal based printed electronics was a newly emerging frontier in recent years. However, restricted by the single silver-white appearance of the liquid metal(LM), the colors of currently available printed electronics were rather limited. Here,a new conceptual LM based colorful printed electronics was proposed where electrical wires and circuits with numerous colors can be made via a straightforward, efficient and accurate printing procedure. Firstly, the LM was printed on the substrate to construct a conductive wire. Then it was frozen to a solid. Subsequently, colorful pigments were coated on the originally printed liquid metal conductive wires, which finally were packaged with PDMS. Such multicolored conductive wire exhibits excellent conductivity, and good temperature resistance(do not fade at high temperature). Further, the adhesion mechanism of the mineral pigments on the liquid metal layer was disclosed. And the pigment layer was discovered to well protect the LM from the outside environments, and enhance the durability of the LM conductive wire at the same time. These multicolored liquid metal wires take an aesthetic appearance, excellent printability, flexibility, large conductivity and stable performance, which would significantly enhance the sense of beauty and experience when compared to the conventional printed electronics.展开更多
It has been more than three decades since stereolithography began to emerge in various forms of additive manufacturing and 3D printing. Today these technologies are proliferating worldwide in various forms of advanced...It has been more than three decades since stereolithography began to emerge in various forms of additive manufacturing and 3D printing. Today these technologies are proliferating worldwide in various forms of advanced manufacturing. The largest segment of the 3D printing market today involves various polymer component fabrications, particularly complex structures not attainable by other manufacturing methods.Conventional printer head systems have also been adapted to selectively print various speciated human cells and special molecules in attempts to construct human organs, beginning with skin and various tissue patches. These efforts are discussed along with metal and alloy fabrication of a variety of implant and bone replacement components by creating powder layers, which are selectively melted into complex forms(such as foams and other open-cellular structures) using laser and electron beams directed by CAD software. Efforts to create a "living implant" by bone ingrowth and eventual vascularization within these implants will be discussed briefly. Novel printer heads for direct metal droplet deposition as in other 3D printing systems are briefly described since these concepts will allow for the eventual fabrication of very large and complex products, including automotive and aerospace structures and components.展开更多
In this work, a simple methodology was developed to enhance the patterning resolution of inkjet printing, involving process optimization as well as substrate modification and treatment. The line width of the inkjetpri...In this work, a simple methodology was developed to enhance the patterning resolution of inkjet printing, involving process optimization as well as substrate modification and treatment. The line width of the inkjetprinted silver lines was successfully reduced to 1/3 of the original value using this methodology. Large-area flexible circuits with delicate patterns and good morphology were thus fabricated. The resultant flexible circuits showed excellent electrical conductivity as low as 4.5 Ω/□ and strong tolerance to mechanical bending. The simple methodology is also applicable to substrates with various wettability, which suggests a general strategy to enhance the printing quality of inkjet printing for manufacturing high-performance large-area flexible electronics.展开更多
This study explores the feasibility of different laser systems to sinter screen-printed lines from nonconductive copper nanoparticles(Cu NPs)on polyethylene terephthalate polymer film.These materials are commonly used...This study explores the feasibility of different laser systems to sinter screen-printed lines from nonconductive copper nanoparticles(Cu NPs)on polyethylene terephthalate polymer film.These materials are commonly used in manufacturing functional printed electronics for large-area applications.Here,optical and thermal characterization of the materials is conducted to identify suitable laser sources and process conditions.Direct diode(808 nm),Nd:YAG(1064 nm and second harmonic of 532 nm),and ytterbium fiber(1070 nm)lasers are explored.Optimal parameters for sintering the Cu NPs are identified for each laser system,which targets low resistivity and high processing speed.Finally,the quality of the sintered tracks is quantified,and the laser sintering mechanisms observed under different wavelengths are analyzed.Practical considerations are discussed to improve the laser sintering process of Cu NPs.展开更多
A new generation of RFID materials with de- signed-in compatibility helps raise quality, reliability and process efficiency If RFID technology is headed for the heights predicted by forecasters, it will require an ong...A new generation of RFID materials with de- signed-in compatibility helps raise quality, reliability and process efficiency If RFID technology is headed for the heights predicted by forecasters, it will require an ongoing evolution of new materials and re- lated technologies to help reduce card/label assembly costs and improve performance. From a materials standpoint, the critical elements in any printed RFID inlay include the chip, the chip attachment method, the antenna,展开更多
Surface tension plays a core role in dominating various surface and interface phenomena. For liquid metals with high melting temperature, a profound understanding of the behaviors of surface tension is crucial in indu...Surface tension plays a core role in dominating various surface and interface phenomena. For liquid metals with high melting temperature, a profound understanding of the behaviors of surface tension is crucial in industrial processes such as casting, welding, and solidification, etc. Recently, the room temperature liquid metal (RTLM) mainly composed of gallium-based alloys has caused widespread concerns due to its increasingly realized unique virtues. The surface properties of such materials are rather vital in nearly all applications involved from chip cooling, thermal energy harvesting, hydrogen generation, shape changeable soft machines, printed electronics to 3D fabrication, etc. owing to its pretty large surface tension of approximately 700 mN/m. In order to promote the research of surface tension of RTLM, this paper is dedicated to present an overview on the roles and mechanisms of surface tension of liquid metal and summarize the latest progresses on the understanding of the basic knowledge, theories, influencing factors and experimental measure- ment methods clarified so far. As a practical technique to regulate the surface tension of RTLM, the fimdamental principles and applications of electrowetting are also interpreted. Moreover, the unique phenomena of RTLM surface tension issues such as surface tension driven self- actuation, modified wettability on various substrates and the functions of oxides are discussed to give an insight into the acting mechanism of surface tension. Furthermore, future directions worthy of pursuing are pointed out.展开更多
Graphene oxide and silver nanowires were bar coated onto polyethylene terephthalate (PET) substrates and then welded using an ultraviolet (UV)-assisted flash light irradiation process to achieve both high electric...Graphene oxide and silver nanowires were bar coated onto polyethylene terephthalate (PET) substrates and then welded using an ultraviolet (UV)-assisted flash light irradiation process to achieve both high electrical conductivity and low haze. The irradiation process connected adjacent silver nanowires by welding, while simultaneously reducing the graphene oxide to graphene. This process was performed using a custom W-assisted flash light welding system at room temperature under ambient conditions and was extremely rapid, with processing time of several milliseconds. The effects of varying the weight fractions of the silver nanowires and graphene oxide and of varying the W-assisted flash light welding conditions (light energy and pulse duration) were investigated. The surface morphologies of the welded silver nanowire/graphene films were analyzed using scanning electron microscopy. Optical characterizations, including transmittance and haze measurements, were also conducted using a spectrophotometer. To test their resistance to oxidation, the welded silver nanowire/graphene films were subjected to high temperature in a furnace (100 ℃), and their sheet resistances were measured every hour. The flash light welding process was found to yield silver nanowire/graphene films with high oxidation resistance, high conductivity (14.35 Ω·sq-1), high transmittance (93.46%), and low haze (0.9%). This material showed uniform temperature distribution when applied as a resistive heating film.展开更多
With the rapid development of deep space exploration and commercial flight, a series of tough scientific and technological challenges were raised, which urgently require ever advanced technologies to tackle with. Rece...With the rapid development of deep space exploration and commercial flight, a series of tough scientific and technological challenges were raised, which urgently require ever advanced technologies to tackle with. Recently, liquid metals, as a kind of newly emerging functional material, are attracting various attention and many breakthroughs have been made on earth. Such a scientific trend also suggests promising approaches for solving those extreme challenges in space environment. To fulfill the increasing needs thus involved, this article is dedicated to systematically introducing liquid metal material and its related disciplines into space science and technology. Firstly, existing application of liquid metal cooling for space nuclear power was summarized. Then, some potential space practices were tentatively put forward, such as liquid metal thermal interface medium,liquid metal phase change material, liquid metal convection cooling, metal alloy thermal storage, liquid metal electromagnetic shielding and liquid metal electronic printing. Fundamental as well as practical issues that would differ with earth were interpreted. Finally, potential liquid metal space experiments were proposed to investigate the liquid metal hydrodynamic characteristic, wettability and phase change mechanism in space physical environment. Overall, liquid metal enabled space science and technology investigation will not only help efficiently solve the current and future space technological problems, but also aid to stimulate the advancement of liquid metal space material science.展开更多
Fully printed perovskite solar cells(PSCs)were fabricated in air with all constituent layers,except for electrodes,deposited by the blade coating technique.The PSCs incorporated,for the first time,a nanometer-thick pr...Fully printed perovskite solar cells(PSCs)were fabricated in air with all constituent layers,except for electrodes,deposited by the blade coating technique.The PSCs incorporated,for the first time,a nanometer-thick printed bathocuproine(BCP)hole blocking buffer using blade coating and deposited at relative humidity up to 50%.The PSCs with a p-i-n structure(glass/indium tin oxide(ITO)/poly(3,4-ethylenedioxythiophene)polystyrene sulfonate(PEDOT:PSS)/CH_(3)NH_(3)Pbl_(3)/[6,6]-phenyl-C_(61)-butyric acid methyl ester(PCBM)/BCP/Ag)delivered a maximum power conversion efficiency(PCE)of 14.9%on an active area of 0.5 cm^(2)when measured under standard test conditions.The PSCs with a blade coated BCP delivered performance of 10%and 63%higher(in relative terms)than those incorporating a spin coated BCP or without any BCP film,respectively.The atomic force microscopy(AFM)showed that blade coated films were more homogeneous and acted also as a surface planarizer leading to a reduction of roughness which improved BCP/Ag interface lowering charge recombination.The demonstration of 15%efficient devices with all constituent layers,including nanometer-thick BCP(〜10 nm),deposited by blade coating in air,demonstrates a route for industrialization of this technology.展开更多
In this paper, a flexible and stretchable circuit has been fabricated by the printing method based on Ag NWs/PDMS composite. The randomly oriented Ag NWs were buried in PDMS to form a conductive and stretchable electr...In this paper, a flexible and stretchable circuit has been fabricated by the printing method based on Ag NWs/PDMS composite. The randomly oriented Ag NWs were buried in PDMS to form a conductive and stretchable electrode. Stable conductivity was achieved with a large range of tensile strain(0-50%) after the initial stretching/releasing cycle. The stable electrical response is due to the buckling of the Ag NWs/PDMS composite layer. Furthermore, printed stretchable circuits integrated with commercial ICs have been demonstrated for wearable applications.展开更多
We combined lightweight and mechanically flexible printed transistors and actuators with a paper unmanned aerial vehicle(UAV)glider prototype to demonstrate electrically controlled glide path modification in a lightwe...We combined lightweight and mechanically flexible printed transistors and actuators with a paper unmanned aerial vehicle(UAV)glider prototype to demonstrate electrically controlled glide path modification in a lightweight,disposable UAV system.The integration of lightweight and mechanically flexible electronics that is offered by printed electronics is uniquely attractive in this regard because it enables flight control in an inexpensive,disposable,and easily integrated system.Here,we demonstrate electroactive polymer(EAP)actuators that are directly printed into paper that act as steering elements for low cost,lightweight paper UAVs.We drive these actuators by using ion gel-gated organic thin film transistors(OTFTs)that are ideally suited as drive transistors for these actuators in terms of drive current and frequency requirements.By using a printing-based fabrication process on a paper glider,we are able to deliver an attractive path to the realization of inexpensive UAVs for ubiquitous sensing and monitoring flight applications.展开更多
The printed electronics technology can be used to efficiently construct smart devices and is dependent on functional inks containing well-dispersed active materials.Two-dimensional(2D)materials are promising functiona...The printed electronics technology can be used to efficiently construct smart devices and is dependent on functional inks containing well-dispersed active materials.Two-dimensional(2D)materials are promising functional ink candidates due to their superior properties.However,the majority 2D materials can disperse well only in organic solvents or in surfactant-assisted water solutions,which limits their applications.Herein,we report a lithium(Li)-ion exchange method to improve the dispersity of the Na_(2)W_(4)O_(13) nanosheets in pure water.The Li-ion-exchanged Na_(2)W_(4)0_(13)(Li_(x)Na_(2-x)W_(4)O_(13))nanosheets show highly stable dispersity in water with a zeta potential of-55 mV.Moreover,this aqueous ink can be sprayed on various substrates to obtain a uniform LixNa2_xW4O13 nanosheet film,exhibiting an excellent electrochromic performance.A complementary electrochromic device containing a Li_(x)Na_(2-x)W_(4)O_(13) nanosheet film as an electrochromic layer and Prussian white(PW)as an ion storage layer exhibits a large optical modulation of 75% at 700 nm,a fast switching response of less than 2 s,and outstanding cyclic stability.This Na2W4Oi3-based aqueous ink exhibits considerable potential for fabricating large-scale and flexible electrochromic devices,which would meet the practical application requirements.展开更多
Fabricating high integration density,high resolution,and intrinsically stretchable patterns by patterned technologies remain challenging.Template printing enabled high-precision patterned fabrication at a facile opera...Fabricating high integration density,high resolution,and intrinsically stretchable patterns by patterned technologies remain challenging.Template printing enabled high-precision patterned fabrication at a facile operation.However,the pattern spacing constraint is the major limitation to high integration density.In this study,we develop an elastomer-assisted strategy to improve the template printing process,which involves patterning on the prestrain elastic substrate.This strategy overcomes the spacing limitation and enables the realization of a centimeter-scale pattern with submicron precision.Particularly,the integration density of fabricated intrinsically stretchable patterns can reach 1932 lines on a substrate of 0.5 cm2;the assembly lines with a feature size of 880 nm and an interval of 955 nm.Furthermore,we demonstrate a facile approach for constructing silver nanoparticle/liquid metal alloy composite conductive patterns.The as-prepared flexible electrodes can withstand up to 150%strain and a 2-mm bend radius.This method provides new insights into template printing technology.Additionally,it opens a route for the simultaneous construction of functional patterned arrays with large scale,high integration density,and intrinsic stretchability,which will be useful for the integrated fabrication of various flexible electronic devices.展开更多
基金supported in part by Engineering and Physical Science Research Council (EPSRC) through Engineering Fellowship (EP/R029644/1)Hetero-print Programme Grant (EP/R03480X/1)European Commission through grant references (H2020-MSCAITN2019-861166)。
文摘Disposable devices designed for single and/or multiple reliable measurements over a short duration have attracted considerable interest recently. However, these devices often use non-recyclable and non-biodegradable materials and wasteful fabrication methods. Herein, we present ZnO nanowires(NWs) based degradable high-performance UV photodetectors(PDs) on flexible chitosan substrate. Systematic investigations reveal the presented device exhibits excellent photo response, including high responsivity(55 A/W), superior specific detectivity(4×10^(14) jones), and the highest gain(8.5×10~(10)) among the reported state of the art biodegradable PDs. Further, the presented PDs display excellent mechanical flexibility under wide range of bending conditions and thermal stability in the measured temperature range(5–50 ℃).The biodegradability studies performed on the device, in both deionized(DI) water(pH≈6) and PBS solution(pH=7.4),show fast degradability in DI water(20 mins) as compared to PBS(48 h). These results show the potential the presented approach holds for green and cost-effective fabrication of wearable, and disposable sensing systems with reduced adverse environmental impact.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF),Ministry of Education,Science and Technology,Korea(Grant No.2010-0026163)Strategy Technology Development Project,Ministry of Knowledge Economy,Korea(Grant No.10032149)
文摘The mass production of primed electronics can be achieved by roll-to-roll(R2R) printing system, so highly accurate web tension is required that can minimize the register error and keep the thickness and roughness of printed devices in limits. The web tension of a R2R system is regulated by the use of integrated load cells and active dancer system for printed electronics applications using decentralized multi-input-single-output(MISO) regularized variable learning rate backpropagation artificial neural networks. The active dancer system is used before printing system to reduce disturbances in the web tension of process span. The classical PID control result in tension spikes with the change in roll diameter of winder and unwinder rolls. The presence of dancer in R2R system shows that improved web tension control in printing span and the web tension can be enhanced from 3.75 N to 4.75 N. The overshoot of system is less than ±2.5 N and steady state error is within ± 1 N where load cells have a signal noise of ±0.7 N. The integration of load cells and active dancer with self-adapting neural network control provide a solution to the web tension control of multispan roll-to-roll system.
基金This research was financially supported under the Westlake Multidisciplinary Research Initiative Center(MRIC)Seed Fund(Grant No.MRIC20200101).
文摘Metal oxide thin-films transistors(TFTs)produced from solution-based printing techniques can lead to large-area electronics with low cost.However,the performance of current printed devices is inferior to those from vacuum-based methods due to poor film uniformity induced by the“coffeering”effect.Here,we report a novel approach to print highperformance indium tin oxide(ITO)-based TFTs and logic inverters by taking advantage of such notorious effect.ITO has high electrical conductivity and is generally used as an electrode material.However,by reducing the film thickness down to nanometers scale,the carrier concentration of ITO can be effectively reduced to enable new applications as active channels in transistors.The ultrathin(~10-nm-thick)ITO film in the center of the coffee-ring worked as semiconducting channels,while the thick ITO ridges(>18-nm-thick)served as the contact electrodes.The fully inkjet-printed ITO TFTs exhibited a high saturation mobility of 34.9 cm2 V^(−1) s^(−1) and a low subthreshold swing of 105 mV dec^(−1).In addition,the devices exhibited excellent electrical stability under positive bias illumination stress(PBIS,ΔV_(th)=0.31 V)and negative bias illuminaiton stress(NBIS,ΔV_(th)=−0.29 V)after 10,000 s voltage bias tests.More remarkably,fully printed n-type metal–oxide–semiconductor(NMOS)inverter based on ITO TFTs exhibited an extremely high gain of 181 at a low-supply voltage of 3 V,promising for advanced electronics applications.
文摘In order to overcome the shortcomings of low-cost anti-oxidation conductive ink and its preparation method in the field of printing electronics, core-shell coated Cu@Ag nanoparticles were used to prepare conductive ink, and a printed circuit was obtained by inkjet printing. Copper nanoparticles were prepared by a chemical reduction method and then coated with Cu@Ag particles by a copper-based self-catalytic reaction. Conductive ink was prepared by ball milling and dispersion and printed on PI film to form a conductive coating. After characterization and analysis, the particle size and dispersion of the obtained Cu@Ag meet the requirements and can be stored stably under normal atmospheric conditions. The resistivity of the conductive film sintered at 300˚C is only 10.6 μΩ<span style="font-size:10.0pt;font-family:"">∙</span>cm.
基金the Philippines’Department of Science and Technology-Engineering Research and Development for Technology program,the Intelligent Systems Laboratory and the iNano Laboratory of the De La Salle University,the Fundação para a Ciência e a Tecnologia(FCT)for funding MARE(Marine and Environmental Sciences Centre,UIDB/04292/2020 and UIDB/04292/2020)ARNET(Aquatic Research Infrastructure Network Associated Laboratory,LA/P/0069/2020)B.Duarte researcher contract(CEECIND/00511/2017).
文摘Nitrate is the primary water-soluble macronutrient essential for plant growth that is converted from excess fish feeds,fish effluents,and degrading biomaterials on the aquaponic pond floor,and when aquacultural malpractices occur,large amounts of it retain in the water system causing increase rate in eutrophication and toxifies fish and aquaculture plants.Recent nitrate sensor prototypes still require performing the additional steps of water sample deionization and dilution and were constructed with expensive materials.In response to the challenge of sensor enhancement and aquaponic water quality monitoring,this study developed sensitive,repeatable,and reproducible screen-printed graphite electrodes on polyvinyl chloride and parchment paper substrates with silver as electrode material and 60:40 graphite powder:nail polish formulated conductive ink for electrical traces,integrated with 9-gene genetic expression model as a function of peak anodic current and electrochemical test time for nitrate concentration prediction that is embedded into low-power Arduino ESP32 for in situ nitrate sensing in aquaponic pond water.Five SPE electrical traces were designed on the two types of substrates.Scanning electron microscopy with energy dispersive X-ray confirmed the electrode surface morphology.Electrochemical cyclic voltammetry using 10 to 100 mg/L KNO3 and water from three-depth regions of the actual pond established the electrochemical test time(10.5 s)and electrode potential(0.135 V)protocol necessary to produce peak current that corresponds to the strength of nitrate ions during redox.The findings from in situ testing revealed that the proposed sensors have strong linear predictions(R2=0.968 MSE=1.659 for nSPEv and R2=0.966 MSE=4.697 for nSPEp)in the range of 10 to 100 mg/L and best detection limit of 3.15μg/L,which are comparable to other sensors of more complex construction.The developed three-electrode electrochemical nitrate sensor confirms that it is reliable for both biosensing in controlled solutions and in situ aquaponic pond water systems.
基金support from the National Natural Science Foundation of China(Grant No.52175441)the Natural Science Foundation of Zhejiang Province,China(Grant No.LD22E050010)+4 种基金the travel scholarship from the China Scholarship Council(Grant No.202208330333)for secondment of Jiahuan Wang at London South Bank University(LSBU)for working closely with Prof.GoelSaurav Goel would like to acknowledge the funding support from UK Research and Innovation,UKRI(Grant Nos.EP/S036180/1 and EP/T024607/1)the feasibility study awards to LSBU from the UKRI National Interdisciplinary Circular Economy Hub(Grant No.EP/V029746/1)Transforming the Foundation Industries:A Network+(Grant No.EP/V026402/1)the International Exchange Cost Share Award by the Royal Society(Grant No.IEC\NSFC\223536).This work accessed the supercomputing service(Isambard-AI,Bristol,UK)via the Resource Allocation Panel and Kittrick(LSBU)-based computational resources.
文摘Printed circuit boards(PCBs)are representative composite materials,and their high-quality drilling machining remains a persistent challenge in the industry.The finishing of the cutting edge of a microdrill is crucial to drill performance in machining fine-quality holes with a prolonged tool life.The miniature size involving submicron scale geometric dimensions,a complex flute shape,and low fracture toughness makes the cutting edge of microdrills susceptible to breakage and has been the primary limiting factor in edge preparation for microdrills.In this study,a newly developed cutting edge preparation method for microdrills was tested experimentally on electronic printed circuit boards.The proposed method,namely,shear thickening polishing,limited the cutting edge burrs and chipping on the cutting edge,and this in turn transformed the cutting edge’s radius from being sharp to smooth.Moreover,the edge–edge radius could be regulated by adjusting the processing time.PCB drilling experiments were conducted to investigate the influence of different cutting edge radii on wear,hole position accuracy,nail head value,and hole wall roughness.The proposed approach showed 20%enhancement in hole position accuracy,33%reduction in the nail head value,and 19%reduction in hole wall roughness compared with the original microdrill.However,a threshold is needed;without it,excessive shear thickening polishing will result in a blunt edge,which may accelerate the wear of the microdrill.Wear was identified as the primary factor that reduced hole quality.The study indicates that in printed circuit board machining,microdrills should effectively eliminate grinding defects and maintain the sharpness of the cutting edge as much as possible to obtain excellent drilling quality.Overall,shear thickening polishing is a promising method for cutting edge preparation of microdrills.Further research and optimization can lead to additional improvements in microdrill performance and contribute to the continued advancement of printed circuit board manufacturing.
基金supported by Beijing Municipal Science and Technology Funding(Grant No.Z151100003715002)Key Project Funding of Chinese Academy of Sciences
文摘Liquid metal based printed electronics was a newly emerging frontier in recent years. However, restricted by the single silver-white appearance of the liquid metal(LM), the colors of currently available printed electronics were rather limited. Here,a new conceptual LM based colorful printed electronics was proposed where electrical wires and circuits with numerous colors can be made via a straightforward, efficient and accurate printing procedure. Firstly, the LM was printed on the substrate to construct a conductive wire. Then it was frozen to a solid. Subsequently, colorful pigments were coated on the originally printed liquid metal conductive wires, which finally were packaged with PDMS. Such multicolored conductive wire exhibits excellent conductivity, and good temperature resistance(do not fade at high temperature). Further, the adhesion mechanism of the mineral pigments on the liquid metal layer was disclosed. And the pigment layer was discovered to well protect the LM from the outside environments, and enhance the durability of the LM conductive wire at the same time. These multicolored liquid metal wires take an aesthetic appearance, excellent printability, flexibility, large conductivity and stable performance, which would significantly enhance the sense of beauty and experience when compared to the conventional printed electronics.
基金based by the Office of Research and Sponsored Projects at The University of Texas at El Paso
文摘It has been more than three decades since stereolithography began to emerge in various forms of additive manufacturing and 3D printing. Today these technologies are proliferating worldwide in various forms of advanced manufacturing. The largest segment of the 3D printing market today involves various polymer component fabrications, particularly complex structures not attainable by other manufacturing methods.Conventional printer head systems have also been adapted to selectively print various speciated human cells and special molecules in attempts to construct human organs, beginning with skin and various tissue patches. These efforts are discussed along with metal and alloy fabrication of a variety of implant and bone replacement components by creating powder layers, which are selectively melted into complex forms(such as foams and other open-cellular structures) using laser and electron beams directed by CAD software. Efforts to create a "living implant" by bone ingrowth and eventual vascularization within these implants will be discussed briefly. Novel printer heads for direct metal droplet deposition as in other 3D printing systems are briefly described since these concepts will allow for the eventual fabrication of very large and complex products, including automotive and aerospace structures and components.
基金supported by the National Key Basic Research Program of China(Nos.2014CB648300,2017YFB0404501)the National Natural Science Foundation of China(Nos.21422402,21674050)+8 种基金the Natural Science Foundation of Jiangsu Province(Nos.BK20140060,BK20130037,BK20140865,BM2012010)the Program for Jiangsu Specially-Appointed Professors(No.RK030STP15001)the Program for New Century Excellent Talents in University(No.NCET-13-0872)the NUPT"1311 Project"and Scientific Foundation(Nos.NY213119,NY213169)the Synergetic Innovation Center for Organic Electronics and Information Displays,the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Leading Talent of Technological Innovation of National Ten Thousands Talents Program of Chinathe Excellent Scientific and Technological Innovative Teams of Jiangsu Higher Education Institutions(No.TJ217038)the Program for Graduate Students Research and Innovation of Jiangsu Province(No.KYZZ16-0253)the 333 Project of Jiangsu Province(Nos.BRA2017402,BRA2015374)
文摘In this work, a simple methodology was developed to enhance the patterning resolution of inkjet printing, involving process optimization as well as substrate modification and treatment. The line width of the inkjetprinted silver lines was successfully reduced to 1/3 of the original value using this methodology. Large-area flexible circuits with delicate patterns and good morphology were thus fabricated. The resultant flexible circuits showed excellent electrical conductivity as low as 4.5 Ω/□ and strong tolerance to mechanical bending. The simple methodology is also applicable to substrates with various wettability, which suggests a general strategy to enhance the printing quality of inkjet printing for manufacturing high-performance large-area flexible electronics.
基金The corresponding author,Hongyu Zheng,would like to acknowledge the grant support of Shandong Taishan Scholar Scheme(Grant No.ts20190401).
文摘This study explores the feasibility of different laser systems to sinter screen-printed lines from nonconductive copper nanoparticles(Cu NPs)on polyethylene terephthalate polymer film.These materials are commonly used in manufacturing functional printed electronics for large-area applications.Here,optical and thermal characterization of the materials is conducted to identify suitable laser sources and process conditions.Direct diode(808 nm),Nd:YAG(1064 nm and second harmonic of 532 nm),and ytterbium fiber(1070 nm)lasers are explored.Optimal parameters for sintering the Cu NPs are identified for each laser system,which targets low resistivity and high processing speed.Finally,the quality of the sintered tracks is quantified,and the laser sintering mechanisms observed under different wavelengths are analyzed.Practical considerations are discussed to improve the laser sintering process of Cu NPs.
文摘A new generation of RFID materials with de- signed-in compatibility helps raise quality, reliability and process efficiency If RFID technology is headed for the heights predicted by forecasters, it will require an ongoing evolution of new materials and re- lated technologies to help reduce card/label assembly costs and improve performance. From a materials standpoint, the critical elements in any printed RFID inlay include the chip, the chip attachment method, the antenna,
文摘Surface tension plays a core role in dominating various surface and interface phenomena. For liquid metals with high melting temperature, a profound understanding of the behaviors of surface tension is crucial in industrial processes such as casting, welding, and solidification, etc. Recently, the room temperature liquid metal (RTLM) mainly composed of gallium-based alloys has caused widespread concerns due to its increasingly realized unique virtues. The surface properties of such materials are rather vital in nearly all applications involved from chip cooling, thermal energy harvesting, hydrogen generation, shape changeable soft machines, printed electronics to 3D fabrication, etc. owing to its pretty large surface tension of approximately 700 mN/m. In order to promote the research of surface tension of RTLM, this paper is dedicated to present an overview on the roles and mechanisms of surface tension of liquid metal and summarize the latest progresses on the understanding of the basic knowledge, theories, influencing factors and experimental measure- ment methods clarified so far. As a practical technique to regulate the surface tension of RTLM, the fimdamental principles and applications of electrowetting are also interpreted. Moreover, the unique phenomena of RTLM surface tension issues such as surface tension driven self- actuation, modified wettability on various substrates and the functions of oxides are discussed to give an insight into the acting mechanism of surface tension. Furthermore, future directions worthy of pursuing are pointed out.
文摘Graphene oxide and silver nanowires were bar coated onto polyethylene terephthalate (PET) substrates and then welded using an ultraviolet (UV)-assisted flash light irradiation process to achieve both high electrical conductivity and low haze. The irradiation process connected adjacent silver nanowires by welding, while simultaneously reducing the graphene oxide to graphene. This process was performed using a custom W-assisted flash light welding system at room temperature under ambient conditions and was extremely rapid, with processing time of several milliseconds. The effects of varying the weight fractions of the silver nanowires and graphene oxide and of varying the W-assisted flash light welding conditions (light energy and pulse duration) were investigated. The surface morphologies of the welded silver nanowire/graphene films were analyzed using scanning electron microscopy. Optical characterizations, including transmittance and haze measurements, were also conducted using a spectrophotometer. To test their resistance to oxidation, the welded silver nanowire/graphene films were subjected to high temperature in a furnace (100 ℃), and their sheet resistances were measured every hour. The flash light welding process was found to yield silver nanowire/graphene films with high oxidation resistance, high conductivity (14.35 Ω·sq-1), high transmittance (93.46%), and low haze (0.9%). This material showed uniform temperature distribution when applied as a resistive heating film.
基金supported by the Key Project of the National Natural Science Foundation of China (Grant No. 91748206)the Frontier Project of the Chinese Academy of Sciences and Dean’s Research Funding。
文摘With the rapid development of deep space exploration and commercial flight, a series of tough scientific and technological challenges were raised, which urgently require ever advanced technologies to tackle with. Recently, liquid metals, as a kind of newly emerging functional material, are attracting various attention and many breakthroughs have been made on earth. Such a scientific trend also suggests promising approaches for solving those extreme challenges in space environment. To fulfill the increasing needs thus involved, this article is dedicated to systematically introducing liquid metal material and its related disciplines into space science and technology. Firstly, existing application of liquid metal cooling for space nuclear power was summarized. Then, some potential space practices were tentatively put forward, such as liquid metal thermal interface medium,liquid metal phase change material, liquid metal convection cooling, metal alloy thermal storage, liquid metal electromagnetic shielding and liquid metal electronic printing. Fundamental as well as practical issues that would differ with earth were interpreted. Finally, potential liquid metal space experiments were proposed to investigate the liquid metal hydrodynamic characteristic, wettability and phase change mechanism in space physical environment. Overall, liquid metal enabled space science and technology investigation will not only help efficiently solve the current and future space technological problems, but also aid to stimulate the advancement of liquid metal space material science.
基金We acknow ledge Petroleo Brasileiro S.A.(PETROBRAS)under the project“Research and Development of Perovskite form ulations for production of printed photovoltaic cells and modulesM for funding.S.C.-H and T.M.B.acknowledge to have received funding from Departamen to del Huila’s Scholarship Program No.677 from Huila,Colombia,the European Unions H orizon 2020 research and innovation program under grant agreement no.763989 APOLO,Lazio Region“Gruppi di Ricerca”under project no.85-2017-15373(SIROH)according to L.R.Lazio 13/08,and the Italian Ministry o f University and Research(MIUR)through the PRIN2017 BOOSTER(project n.2017YXX8AZ)grant.This publication reflects only the authors' views and the funding agencies are not liable for any use that may be made of the inform ation contained therein.We thank to Gabriela Amorim for solar cell encapsulation.We thank engineering departm ent at CSEM Brasil for developing the nitrogen blower system.We thank to Centro de Microscopia,Laboratorio de Caracterizacao e de Processam ento de Nanom ateriais from Federal University of M inas Gerais,for providing the experimental facilities and Prof.Wagner da Nova Mussel for XRD results.
文摘Fully printed perovskite solar cells(PSCs)were fabricated in air with all constituent layers,except for electrodes,deposited by the blade coating technique.The PSCs incorporated,for the first time,a nanometer-thick printed bathocuproine(BCP)hole blocking buffer using blade coating and deposited at relative humidity up to 50%.The PSCs with a p-i-n structure(glass/indium tin oxide(ITO)/poly(3,4-ethylenedioxythiophene)polystyrene sulfonate(PEDOT:PSS)/CH_(3)NH_(3)Pbl_(3)/[6,6]-phenyl-C_(61)-butyric acid methyl ester(PCBM)/BCP/Ag)delivered a maximum power conversion efficiency(PCE)of 14.9%on an active area of 0.5 cm^(2)when measured under standard test conditions.The PSCs with a blade coated BCP delivered performance of 10%and 63%higher(in relative terms)than those incorporating a spin coated BCP or without any BCP film,respectively.The atomic force microscopy(AFM)showed that blade coated films were more homogeneous and acted also as a surface planarizer leading to a reduction of roughness which improved BCP/Ag interface lowering charge recombination.The demonstration of 15%efficient devices with all constituent layers,including nanometer-thick BCP(〜10 nm),deposited by blade coating in air,demonstrates a route for industrialization of this technology.
基金supported by the National Program on Key Basic Research Project(No.2015CB351901)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA09020201)the National Science Foundation of China(Nos.51603227,51603228)
文摘In this paper, a flexible and stretchable circuit has been fabricated by the printing method based on Ag NWs/PDMS composite. The randomly oriented Ag NWs were buried in PDMS to form a conductive and stretchable electrode. Stable conductivity was achieved with a large range of tensile strain(0-50%) after the initial stretching/releasing cycle. The stable electrical response is due to the buckling of the Ag NWs/PDMS composite layer. Furthermore, printed stretchable circuits integrated with commercial ICs have been demonstrated for wearable applications.
文摘We combined lightweight and mechanically flexible printed transistors and actuators with a paper unmanned aerial vehicle(UAV)glider prototype to demonstrate electrically controlled glide path modification in a lightweight,disposable UAV system.The integration of lightweight and mechanically flexible electronics that is offered by printed electronics is uniquely attractive in this regard because it enables flight control in an inexpensive,disposable,and easily integrated system.Here,we demonstrate electroactive polymer(EAP)actuators that are directly printed into paper that act as steering elements for low cost,lightweight paper UAVs.We drive these actuators by using ion gel-gated organic thin film transistors(OTFTs)that are ideally suited as drive transistors for these actuators in terms of drive current and frequency requirements.By using a printing-based fabrication process on a paper glider,we are able to deliver an attractive path to the realization of inexpensive UAVs for ubiquitous sensing and monitoring flight applications.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.11874036,51872101,51672097,51972124,and 51902115)the National Program for Support of Top-notch Young Professionals,the Program for HUST Academic Frontier Youth Team,the Fundamental Research Funds for the Central Universities(HUST:2017KFXKJC001 and 2018KFYXKJC025)+2 种基金the Guangdong Province Key Area R&D Program(No.2019B010940001)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01N111)Basic Research Project of Shenzhen,China(No.JCYJ20170412171430026).
文摘The printed electronics technology can be used to efficiently construct smart devices and is dependent on functional inks containing well-dispersed active materials.Two-dimensional(2D)materials are promising functional ink candidates due to their superior properties.However,the majority 2D materials can disperse well only in organic solvents or in surfactant-assisted water solutions,which limits their applications.Herein,we report a lithium(Li)-ion exchange method to improve the dispersity of the Na_(2)W_(4)O_(13) nanosheets in pure water.The Li-ion-exchanged Na_(2)W_(4)0_(13)(Li_(x)Na_(2-x)W_(4)O_(13))nanosheets show highly stable dispersity in water with a zeta potential of-55 mV.Moreover,this aqueous ink can be sprayed on various substrates to obtain a uniform LixNa2_xW4O13 nanosheet film,exhibiting an excellent electrochromic performance.A complementary electrochromic device containing a Li_(x)Na_(2-x)W_(4)O_(13) nanosheet film as an electrochromic layer and Prussian white(PW)as an ion storage layer exhibits a large optical modulation of 75% at 700 nm,a fast switching response of less than 2 s,and outstanding cyclic stability.This Na2W4Oi3-based aqueous ink exhibits considerable potential for fabricating large-scale and flexible electrochromic devices,which would meet the practical application requirements.
基金Beijing National Laboratory for Molecular Sciences,Grant/Award Numbers:BNLMSCXXM‐202005,2019BMS20003National Natural Science Foundation of China,Grant/Award Number:2018YFA0703200+3 种基金K.C.Wong Education Foundation,and China Postdoctoral Science Foundation,Grant/Award Number:2020M670466External Cooperation Program of Chinese Academy of Sciences,Grant/Award Number:GJHZ201948CAS‐VPST Silk Road Science Fund 2022,Grant/Award Number:121111KYSB20210006National Key R&D Program of China,Grant/Award Numbers:52003276,22175185,52003273,51803217,51773206,91963212,51961145102,22002171。
文摘Fabricating high integration density,high resolution,and intrinsically stretchable patterns by patterned technologies remain challenging.Template printing enabled high-precision patterned fabrication at a facile operation.However,the pattern spacing constraint is the major limitation to high integration density.In this study,we develop an elastomer-assisted strategy to improve the template printing process,which involves patterning on the prestrain elastic substrate.This strategy overcomes the spacing limitation and enables the realization of a centimeter-scale pattern with submicron precision.Particularly,the integration density of fabricated intrinsically stretchable patterns can reach 1932 lines on a substrate of 0.5 cm2;the assembly lines with a feature size of 880 nm and an interval of 955 nm.Furthermore,we demonstrate a facile approach for constructing silver nanoparticle/liquid metal alloy composite conductive patterns.The as-prepared flexible electrodes can withstand up to 150%strain and a 2-mm bend radius.This method provides new insights into template printing technology.Additionally,it opens a route for the simultaneous construction of functional patterned arrays with large scale,high integration density,and intrinsic stretchability,which will be useful for the integrated fabrication of various flexible electronic devices.