Piezoelectric transduction technology enables the direct conversion between mechanical and electrical energy,finding extensive applications in sensing,acoustics,imaging,actuation,and energy harvesting[1].Previous stud...Piezoelectric transduction technology enables the direct conversion between mechanical and electrical energy,finding extensive applications in sensing,acoustics,imaging,actuation,and energy harvesting[1].Previous studies on piezoelectric materials have primarily focused on ceramics or single-crystal materials characterized by wide band gaps(E_(g)>2.0 e V[2])and low electrical conductivity.In contrast,narrow-bandgap(E_(g)<0.5 eV[3])semiconductor materials typically exhibit high electrical conductivity,which is unfavorable for the effective accumulation of charges required to establish a stable voltage response.Consequently,experimental investigations into the piezoelectric effect of narrow-bandgap semiconductors are scarce.展开更多
With the advancement of flexible bioelectronics,developing highly elastic and breathable piezoelectric materials and devices that achieve conformal deformation,synchronous electromechanical coupling with the human bod...With the advancement of flexible bioelectronics,developing highly elastic and breathable piezoelectric materials and devices that achieve conformal deformation,synchronous electromechanical coupling with the human body and high-fidelity collec-tion of biological information remains a significant challenge.Here,a nanoconfinement self-assembly strategy is developed to prepare elastic phenylalanine dipeptide(FF)crystal fibers,in which FF crystals form a unique Mortise-Tenon structure with oriented styrene-block-butadiene-block-styrene molecular beams and thereby obtain elasticity(≈1200%),flexibility(Young’s modulus:0.409±0.031 MPa),piezoelectricity(macroscopic d_(33):10.025±0.33 pC N^(-1)),breathability,and physical stability.Furthermore,elastic FF crystal fibers are used to develop a flexible human physiological movement sensing system by integrating Ga–In alloy coating and wireless electronic transmission components.The system can undergo conformal deformation with human skin and achieve high-fidelity capture of biological information originating from human body motions to prevent diseases(such as Parkinson’s disease).In addition,this system also displays superior sensitivity and accu-racy in detecting subtle pressure changes in vivo during heartbeats,respiration,and diaphragm movement.Therefore,elastic FF crystal fibers hold great potential for developing new flexible electromechanical sensors that are capable of conformal deformation with the human body,enabling precision medical diagnosis and efficient energy harvesting.展开更多
Piezoelectric materials are capable of converting between mechanical and electrical energy,and are suitable for sensing,actuating and energy harvesting.While most conventional piezoelectric materials are brittle solid...Piezoelectric materials are capable of converting between mechanical and electrical energy,and are suitable for sensing,actuating and energy harvesting.While most conventional piezoelectric materials are brittle solids,flexible piezoelectric materials(FPM)retain functionality even under bending and stretching conditions.This characteristic has garnered increasing attention in recent years,particularly for wearable devices,where the ability to adapt to dynamic human movements is essential.In addition,wearable devices also demand excellent conformability,durability,and adaptability to miniaturization.FPM emerge as a promising solution that meet all these requirements.This review thus aims to offer a comprehensive summary of recent advances in the field of FPM,including piezoelectric polymers,composites,and inorganic flexible films.We introduce and categorize the specific features of these materials and highlight their emerging applications in electronic devices,and comment on the prospect of FPM as well as their potential challenges.展开更多
In the last few years,there has been tremendous effort to develop lead-free ferroelectric ceramics with high piezoelectric properties by various doping and alloying routes.Several material systems have been explored,h...In the last few years,there has been tremendous effort to develop lead-free ferroelectric ceramics with high piezoelectric properties by various doping and alloying routes.Several material systems have been explored,however,no prominent alternative to the versatile lead zirconate titanate(PZT)system has been found yet.Despite the achieved improvement in piezoelectric properties,there are problems in the synthesis,processing and poling of the sintered ceramics.Various processing techniques including microwave,hydrothermal,solgel,Pechini and spark plasma sintering have been used to overcome the drawbacks related to synthesis issues.In this paper,an attempt is made to review recent developments on lead-free piezo materials emphasizing their preparation,structureproperty relations,and consequent physical properties.In this context,both compositional and structural engineering approaches to achieve acceptable piezoelectric properties in lead-free materials are discussed.Piezoelectric properties of the most promising lead-free compositions/families including titanates,alkaline niobates and bismuth perovskites and their solid solutions,along with non-perovskites such as bismuth layer-structured ferroelectrics are reviewed in detail.A brief coverage of the recent developments in the area of piezoelectric energy harvesting is also encompassed.展开更多
Flexible piezoelectrics realise the conversion between mechanical movements and electrical power by conformally attaching onto curvilinear surfaces,which are promising for energy harvesting of biomedical devices due t...Flexible piezoelectrics realise the conversion between mechanical movements and electrical power by conformally attaching onto curvilinear surfaces,which are promising for energy harvesting of biomedical devices due to their sustainable body movements and/or deformations.Developing secondary functions of flexible piezoelectric energy harvesters is becoming increasingly significant in recent years via aiming at issues that cannot be addressed or mitigated by merely increasing piezoelectric efficiencies.These issues include loose interfacial contact and pucker generation by stretching,power shortage or instability induced by inadequate mechanical energy,and premature function degeneration or failure caused by fatigue fracture after cyclic deformations.Herein,the expedient secondary functions of flexible piezoelectrics to mitigate above issues are reviewed,including stretchability,hybrid energy harvesting,and self-healing.Efforts have been devoted to understanding the state-of-the-art strategies and their mechanisms of achieving secondary functions based on piezoelectric fundamentals.The link between structural characteristic and function performance is unravelled by providing insights into carefully selected progresses.The remaining challenges of developing secondary functions are proposed in the end with corresponding outlooks.The current work hopes to help and inspire future research in this promising field focusing on developing the secondary functions of flexible piezoelectric energy harvesters.展开更多
Na_(0.5)Bi_(0.5)TiO_(3)-based lead-free piezoelectrics are considered for potential replacement of the lead-based commercial piezoceramics in high-power transducer applications.We have examined the role of grain size ...Na_(0.5)Bi_(0.5)TiO_(3)-based lead-free piezoelectrics are considered for potential replacement of the lead-based commercial piezoceramics in high-power transducer applications.We have examined the role of grain size in influencing the structural-polar inhomogeneity of stoichiometric and off-stoichiometric Na_(0.5)Bi_(0.5)TiO_(3)(NBT),and its morphotropic-phase-boundary(MPB)derivative 0.94Na_(0.5)Bi_(0.5)TiO_(3)-0.06BaTiO_(3)(NBT-6BT).Our study reveals that size effect comes into play in these systems on a very large length scale(on the scale of microns)considerably affecting its global structure and properties.展开更多
Improving device efficiency is fundamental for advancing energy harvesting technology,particularly in systems designed to convert light energy into electrical output.In our previous studies,we developed a basic struct...Improving device efficiency is fundamental for advancing energy harvesting technology,particularly in systems designed to convert light energy into electrical output.In our previous studies,we developed a basic structure light pressure electric generator(Basic-LPEG),which utilized a layered configuration of Ag/Pb(Zr,Ti)O_(3)(PZT)/Pt/GaAs to generate electricity based on light-induced pressure on the PZT.In this study,we sought to enhance the performance of this Basic-LPEG by introducing Ag nanoparticles/graphene oxide(AgNPs/GO)composite units(NP-LPEG),creating upgraded harvesting device.Specifically,by depositing the AgNPs/GO units twice onto the Basic-LPEG,we observed an increase in output voltage and current from 241 mV and 3.1μA to 310 mV and 9.3μA,respectively,under a solar simulator.The increase in electrical output directly correlated with the intensity of the light pressure impacting the PZT,as well as matched the Raman measurements,finite-difference time-domain simulations,and COMSOL Multiphysics Simulation.Experimental data revealed that the enhancement in electrical output was proportional to the number of hot spots generated between Ag nanoparticles,where the electric field experienced substantial amplification.These results underline the effectiveness of AgNPs/GO units in boosting the light-induced electric generation capacity,thereby providing a promising pathway for high-efficiency energy harvesting devices.展开更多
Pipelines are extensively used in environments such as nuclear power plants,chemical factories,and medical devices to transport gases and liquids.These tubular environments often feature complex geometries,confined sp...Pipelines are extensively used in environments such as nuclear power plants,chemical factories,and medical devices to transport gases and liquids.These tubular environments often feature complex geometries,confined spaces,and millimeter-scale height restrictions,presenting significant challenges to conventional inspection methods.Here,we present an ultrasonic microrobot(weight,80 mg;dimensions,24 mm×7 mm;thickness,210μm)to realize agile and bidirectional navigation in narrow pipelines.The ultrathin structural design of the robot is achieved through a high-performance piezoelectric composite film microstructure based on MEMS technology.The robot exhibits various vibration modes when driven by ultrasonic frequency signals,its motion speed reaches81 cm s-1 at 54.8 k Hz,exceeding that of the fastest piezoelectric microrobots,and its forward and backward motion direction is controllable through frequency modulation,while the minimum driving voltage for initial movement can be as low as 3 VP-P.Additionally,the robot can effortlessly climb slopes up to 24.25°and carry loads more than 36 times its weight.The robot is capable of agile navigation through curved L-shaped pipes,pipes made of various materials(acrylic,stainless steel,and polyvinyl chloride),and even over water.To further demonstrate its inspection capabilities,a micro-endoscope camera is integrated into the robot,enabling real-time image capture inside glass pipes.展开更多
Repolarizing tumor-associated macrophages(TAMs)toward the proinflammatory M1 phenotype represents a promising strategy to reverse the immunosuppressive tumor microenvironment(TME)and enhance antitumor immunotherapy.Re...Repolarizing tumor-associated macrophages(TAMs)toward the proinflammatory M1 phenotype represents a promising strategy to reverse the immunosuppressive tumor microenvironment(TME)and enhance antitumor immunotherapy.Recent studies have demonstrated that exogenous electrical stimulation can effectively repolarize TAMs toward the M1 phenotype.However,conventional electrical stimulation methods,relying on invasive implanted electrodes,are restricted to targeting localized tumor regions and pose inherent risks to patients.Notably,biological neural networks,distributed systems of interconnected neurons,can naturally permeate tissues and orchestrate cellular activities with high spatial efficiency.Inspired by this natural system,we developed a global in situ electric field network using piezoelectric BaTiO_(3)nanoparticles.Upon ultrasound stimulation,the nanoparticles generate a wireless electric field throughout the TME.In addtion,their nanoscale size enables them to function as synthetic“neurons”,allowing for uniform penetration throughout the tumor tissue and inducing significant repolarization of TAMs via the Ca^(2+)influx-activated nuclear factor-kappa B(NF-κB)signaling pathway.The repolarized M1 TAMs restore anti-tumor immunostimulatory functions and secrete key proinflammatory cytokines(e.g.,tumor necrosis factor-alpha(TNF-α)and interleukin-1 beta(IL-1β)),which enhance immunostimulation within the TME and directly contribute to tumor cell elimination.Remarkably,this strategy achieved robust in vivo tumor growth inhibition with excellent biosafety in a 4T1 breast tumor model.Overall,this work establishes a non-invasive,wireless electric field platform capable of globally repolarizing TAMs,offering a safe and efficient strategy to advance cancer immunotherapy and accelerate the clinical translation of bioelectronic therapies.展开更多
Recent advances in ubiquitous low-power electronics call for the development of light-weight and flexible energy sources.The textile format is highly attractive for unobtrusive harvesting of energy from e.g.,biomechan...Recent advances in ubiquitous low-power electronics call for the development of light-weight and flexible energy sources.The textile format is highly attractive for unobtrusive harvesting of energy from e.g.,biomechanical movements.Here,we report the manufacture and characterisation of fully textile piezoelectric generators that can operate under wet conditions.We use a weaving loom to realise textile bands with yarns of melt-spun piezoelectric microfibres,that consist of a conducting core surrounded byβ-phase poly(vinylidene fluoride)(PVDF),in the warp direction.The core-sheath constitution of the piezoelectric microfibres results in a—for electronic textiles—unique architecture.The inner electrode is fully shielded from the outer electrode(made up of conducting yarns that are integrated in the weft direction)which prevents shorting under wet conditions.As a result,and in contrast to other energy harvesting textiles,we are able to demonstrate piezoelectric fabrics that do not only continue to function when in contact with water,but show enhanced performance.The piezoelectric bands generate an output of several volts at strains below one percent.We show that integration into the shoulder strap of a laptop case permits the continuous generation of four microwatts of power during a brisk walk.This promising performance,combined with the fact that our solution uses scalable materials and well-established industrial manufacturing methods,opens up the possibility to develop wearable electronics that are powered by piezoelectric textiles.展开更多
As rapid development in wearable/implantable electronic devices benefit human life in daily health monitoring and disease treatment medically, all kinds of flexible and/or stretchable electronic devices are booming, t...As rapid development in wearable/implantable electronic devices benefit human life in daily health monitoring and disease treatment medically, all kinds of flexible and/or stretchable electronic devices are booming, together with which is the demanding of energy supply with similar mechanical property. Due to its ability in converting mechanical energy lying in human body into electric energy, energy harvesters based on piezoelectric materials are promising for applications in wearable/implantable device's energy supply in a renewable, clean and life-long way. Here the mechanics of traditional piezoelectrics in energy harvesting is reviewed, including why piezoelectricity is the choice for minor energy harvesting to power the implantable/wearable electronics and how. Different kinds of up to date flexible piezoelectric devices for energy harvesting are introduced, such as nanogenerators based on Zn O and thin and conformal energy harvester based on PZT. A detailed theoretical model of the flexible thin film energy harvester based on PZT nanoribbons is summarized, together with the in vivo demonstration of energy harvesting by integrating it with swine heart. Then the initial researches on stretchable energy harvesters based on piezoelectric material in wavy or serpentine configuration are introduced as well.展开更多
Piezoelectric ceramics provide high strain and large driving forces in actuators.A large electrostrain can be realized by the introduction of point defects such as vacancies,interstitial defects,and substitution defec...Piezoelectric ceramics provide high strain and large driving forces in actuators.A large electrostrain can be realized by the introduction of point defects such as vacancies,interstitial defects,and substitution defects.With Mn doping,a significant increase in the reversible electrostrain from 0.05%to 0.17%could be achieved in potassium niobite lead-free piezoelectric ceramics.The origins of the large electrostrain were analyzed via in situ X-ray diffraction(XRD)under an electric field.The electrostrain and other typical electrical properties of the samples were measured at various temperatures,which enabled the ceramics to perform under a very wide temperature range,such as−80–130℃ for the 0.5 mol%Mn-doped sample with low dielectric loss(≤0.02).More importantly,combined with characterizations of the defect behavior by thermally stimulated depolarization current(TSDC),the failure mechanisms of electrostrain in a hightemperature environment could be revealed,which was associated with synergistic damage to the defects caused by the electric field and high temperature.The results can provide good ideas and a basis for the design of piezoelectric materials with good electrostrain stability over a wide temperature range.展开更多
Piezoelectric ceramic materials are important components of piezoelectric buzzers,where the parameter of inverse piezoelectric coefficient(d_(33)^(*))plays a decisive role in the performance of the buzzer.Here,we repo...Piezoelectric ceramic materials are important components of piezoelectric buzzers,where the parameter of inverse piezoelectric coefficient(d_(33)^(*))plays a decisive role in the performance of the buzzer.Here,we report the manufacture and performance of a lead-free ceramic-based(0.96(K_(0.5)Na_(0.5))(Nb_(0.96)Sb_(0.04))O_(3)-0.04(Bi_(0.5)Na_(0.5))ZrO_(3)-1 mol%Al_(2)O_(3),abbreviated as KNNS-BNZ-1 mol%Al_(2)O_(3))piezoelectric buzzer and compare it with commercial(PbZr_(0.5)Ti_(0.5)O_(3),abbreviated as PZT)ceramics.Briefly,KNN-based ceramics have a typical perovskite structure and piezoelectric properties of d_(33)=480 pC/N,k_(p)=0.62 and d_(33)^(*)=830 pm/V,compared to d_(33)=500 pC/N,k_(p)=0.6 and d_(33)^(*)=918 pm/V of the commercial PZT-4 ceramics.Our results show that the KNNS-BNZ-1 mol%Al_(2)O_(3)ceramics have a similar sound pressure level performance over the testing frequency range to commercial PZT ceramics(which is even better in the 3-4 kHz range).These findings highlight the great application potential of KNN-based piezoelectric ceramics.展开更多
Precision actuation is a foundational technology in high-end equipment domains,where stroke,velocity,and accuracy are critical for processing and/or detection quality,precision in spacecraft flight trajectories,and ac...Precision actuation is a foundational technology in high-end equipment domains,where stroke,velocity,and accuracy are critical for processing and/or detection quality,precision in spacecraft flight trajectories,and accuracy in weapon system strikes.Piezoelectric actuators(PEAs),known for their nanometer-level precision,flexible stroke,resistance to electromagnetic interference,and scalable structure,have been widely adopted across various fields.Therefore,this study focuses on extreme scenarios involving ultra-high precision(micrometer and beyond),minuscule scales,and highly complex operational conditions.It provides a comprehensive overview of the types,working principles,advantages,and disadvantages of PEAs,along with their potential applications in piezo-actuated smart mechatronic systems(PSMSs).To address the demands of extreme scenarios in high-end equipment fields,we have identified five representative application areas:positioning and alignment,biomedical device configuration,advanced manufacturing and processing,vibration mitigation,micro robot system.Each area is further divided into specific subcategories,where we explore the underlying relationships,mechanisms,representative schemes,and characteristics.Finally,we discuss the challenges and future development trends related to PEAs and PSMSs.This work aims to showcase the latest advancements in the application of PEAs and provide valuable guidance for researchers in this field.展开更多
The research,fabrication and development of piezoelectric nanofibrous materials offer effective solutions to the challenges related to energy consumption and non-renewable resources.However,enhancing their electrical ...The research,fabrication and development of piezoelectric nanofibrous materials offer effective solutions to the challenges related to energy consumption and non-renewable resources.However,enhancing their electrical output still remains a significant challenge.Here,a strategy of inducing constrained phase separation on single nanofibers via shear force was proposed.Employing electrospinning technology,a polyacrylonitrile/polyvinylidene difluoride(PAN/PVDF)nanofibrous membrane was fabricated in one step,which enabled simultaneous piezoelectric and triboelectric conversion within a single-layer membrane.Each nanofiber contained independent components of PAN and PVDF and exhibited a rough surface.The abundant frictional contact points formed between these heterogeneous components contributed to an enhanced endogenous triboelectric output,showcasing an excellent synergistic effect of piezoelectric and triboelectric response in the nanofibrous membrane.Additionally,the component mass ratio influenced the microstructure,piezoelectric conformation and piezoelectric performance of the PAN/PVDF nanofibrous membranes.Through comprehensive performance comparison,the optimal mass ratio of PAN to PVDF was determined to be 9∶1.The piezoelectric devices made of the optimal PAN/PVDF nanofibrous membranes with rough nanofiber surfaces generated an output voltage of 20 V,which was about 1.8 times that of the smooth one at the same component mass ratio.The strategy of constrained phase separation on the surface of individual nanofibers provides a new approach to enhance the output performance of single-layer piezoelectric nanofibrous materials.展开更多
Recycling plastic waste into triboelectric nanogenerators(TENGs)presents a sustainable approach to energy harvesting,self-powered sensing,and environmental remediation.This study investigates the recycling of polyviny...Recycling plastic waste into triboelectric nanogenerators(TENGs)presents a sustainable approach to energy harvesting,self-powered sensing,and environmental remediation.This study investigates the recycling of polyvinyl chloride(PVC)pipe waste polymers into nanofibers(NFs)optimized for TENG applications.We focused on optimizing the morphology of recycled PVC polymer to NFs and enhancing their piezoelectric properties by incorporating ZnO nanoparticles(NPs).The optimized PVC/0.5 wt%ZnO NFs were tested with Nylon-6 NFs,and copper(Cu)electrodes.The Nylon-6 NFs exhibited a power density of 726.3μWcm^(-2)—1.13 times higher than Cu and maintained 90%stability after 172800 cycles,successfully powering various colored LEDs.Additionally,a 3D-designed device was developed to harvest energy from biomechanical movements such as finger tapping,hand tapping,and foot pressing,making it suitable for wearable energy harvesting,automatic switches,and invisible sensors in surveillance systems.This study demonstrates that recycling polymers for TENG devices can effectively address energy,sensor,and environmental challenges.展开更多
The types of dopants lead to distinctive microstructural evolution behavior and physical properties in materials.In this study,the effect of stoichiometric and non-stoichiometric Mn modification,namely Pb(Mn_(1/3) Nb_...The types of dopants lead to distinctive microstructural evolution behavior and physical properties in materials.In this study,the effect of stoichiometric and non-stoichiometric Mn modification,namely Pb(Mn_(1/3) Nb_(2/3))O_(3)(PMnN)and MnO_(2),on the microstructure and properties of Pb(Yb_(1/2) Nb_(1/2))O_(3)-PbZrO_(3)-PbTiO_(3)(PYN-PZT)piezoelectric ceramics are systematically investigated.It was found that stoichiometric PMnN modification inhibits the grain growth while non-stoichiometric MnO_(2) modification promotes it,and thus the former yields stronger high-power characteristics(higher internal bias field Ei and larger mechanical quality factor Q_(m))than the latter.Specifically,with an equivalent amount of Mn modifica-tion(2 mol%),PMnN and MnO_(2) modification PYN-PZT ceramics exhibit significantly different values for average grain size(1.21μm vs.14.12μm),Ei(8.5 kV/cm vs.5 kV/cm),and Qm(2376 vs.1134).To further evaluate high-power performance,the vibration velocity v of these two modified PYN-PZT under high driving conditions was measured.Under an AC electric field of 3.5 V/mm,the PYN-PZT+6PMnN ceram-ics exhibit a v of up to 0.95 m s^(−1),larger than both MnO2-doped PYN-PZT(0.72 m s^(−1))and unmodified PYN-PZT ceramics(0.1 m s^(−1)),and far outperformance than both PZT-4 and PZT-8 ceramics.Furthermore,to elucidate the origin of the exceptional high-power performance of PMnN-modified PYN-PZT,we per-formed phase-field simulations revealing a pinning effect of the grain boundary on domain wall motion.Consequently,the small grain size(high grain boundary density)in PMnN-modified PYN-PZT exhibits a strong pinning effect,resulting in a large Q_(m) and outstanding high-power performance.展开更多
BiVO_(4)porous spheres modified by ZnO were designed and synthesized using a facile two-step method.The resulting ZnO/BiVO_(4)composite catalysts have shown remarkable efficiency as piezoelectric catalysts for degradi...BiVO_(4)porous spheres modified by ZnO were designed and synthesized using a facile two-step method.The resulting ZnO/BiVO_(4)composite catalysts have shown remarkable efficiency as piezoelectric catalysts for degrading Rhodamine B(RhB)unde mechanical vibrations,they exhibit superior activity compared to pure ZnO.The 40wt%ZnO/BiVO_(4)heterojunction composite displayed the highest activity,along with good stability and recyclability.The enhanced piezoelectric catalytic activity can be attributed to the form ation of an I-scheme heterojunction structure,which can effectively inhibit the electron-hole recombination.Furthermore,hole(h+)and superoxide radical(·O_(2)^(-))are proved to be the primary active species.Therefore,ZnO/BiVO_(4)stands as an efficient and stable piezoelectric catalyst with broad potential application in the field of environmental water pollution treatment.展开更多
High temperature piezoelectric energy harvester(HTPEH)is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors.However,simultaneously excellent performances,inclu...High temperature piezoelectric energy harvester(HTPEH)is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors.However,simultaneously excellent performances,including high figure of merit(FOM),insulation resistivity(ρ)and depolarization temperature(Td)are indispensable but hard to achieve in lead-free piezoceramics,especially operating at 250°C has not been reported before.Herein,well-balanced performances are achieved in BiFeO3–BaTiO3 ceramics via innovative defect engineering with respect to delicate manganese doping.Due to the synergistic effect of enhancing electrostrictive coefficient by polarization configuration optimization,regulating iron ion oxidation state by high valence manganese ion and stabilizing domain orientation by defect dipole,comprehensive excellent electrical performances(Td=340°C,ρ250°C>10^(7)Ωcm and FOM_(250°C)=4905×10^(–15)m^(2)N^(−1))are realized at the solid solubility limit of manganese ions.The HT-PEHs assembled using the rationally designed piezoceramic can allow for fast charging of commercial electrolytic capacitor at 250°C with high energy conversion efficiency(η=11.43%).These characteristics demonstrate that defect engineering tailored BF-BT can satisfy high-end HT-PEHs requirements,paving a new way in developing selfpowered wireless sensors working in HT environments.展开更多
Monitoring minuscule mechanical signals,both in magnitude and direction,is imperative in many application scenarios,e.g.,structural health monitoring and robotic sensing systems.However,the piezoelectric sensor strugg...Monitoring minuscule mechanical signals,both in magnitude and direction,is imperative in many application scenarios,e.g.,structural health monitoring and robotic sensing systems.However,the piezoelectric sensor struggles to satisfy the requirements for directional recognition due to the limited piezoelectric coefficient matrix,and achieving sensitivity for detecting micrometer-scale deformations is also challenging.Herein,we develop a vector sensor composed of lead zirconate titanate-electronic grade glass fiber composite filaments with oriented arrangement,capable of detecting minute anisotropic deformations.The as-prepared vector sensor can identify the deformation directions even when subjected to an unprecedented nominal strain of 0.06%,thereby enabling its utility in accurately discerning the 5μm-height wrinkles in thin films and in monitoring human pulse waves.The ultra-high sensitivity is attributed to the formation of porous ferroelectret and the efficient load transfer efficiency of continuous lead zirconate titanate phase.Additionally,when integrated with machine learning techniques,the sensor’s capability to recognize multi-signals enables it to differentiate between 10 types of fine textures with 100%accuracy.The structural design in piezoelectric devices enables a more comprehensive perception of mechanical stimuli,offering a novel perspective for enhancing recognition accuracy.展开更多
文摘Piezoelectric transduction technology enables the direct conversion between mechanical and electrical energy,finding extensive applications in sensing,acoustics,imaging,actuation,and energy harvesting[1].Previous studies on piezoelectric materials have primarily focused on ceramics or single-crystal materials characterized by wide band gaps(E_(g)>2.0 e V[2])and low electrical conductivity.In contrast,narrow-bandgap(E_(g)<0.5 eV[3])semiconductor materials typically exhibit high electrical conductivity,which is unfavorable for the effective accumulation of charges required to establish a stable voltage response.Consequently,experimental investigations into the piezoelectric effect of narrow-bandgap semiconductors are scarce.
基金support from the National Natural Science Foundation of China(82472159,82302406,52303186)China Postdoctoral Science Foundation(2024T171167,2023M731696,2022TQ0158,2022M721616)+1 种基金Jiangsu Funding Program for Excellent Postdoctoral Talent(2023ZB539,2022ZB250)the Fundamental Research Funds for the Central Universities(30923010307,30920041105).
文摘With the advancement of flexible bioelectronics,developing highly elastic and breathable piezoelectric materials and devices that achieve conformal deformation,synchronous electromechanical coupling with the human body and high-fidelity collec-tion of biological information remains a significant challenge.Here,a nanoconfinement self-assembly strategy is developed to prepare elastic phenylalanine dipeptide(FF)crystal fibers,in which FF crystals form a unique Mortise-Tenon structure with oriented styrene-block-butadiene-block-styrene molecular beams and thereby obtain elasticity(≈1200%),flexibility(Young’s modulus:0.409±0.031 MPa),piezoelectricity(macroscopic d_(33):10.025±0.33 pC N^(-1)),breathability,and physical stability.Furthermore,elastic FF crystal fibers are used to develop a flexible human physiological movement sensing system by integrating Ga–In alloy coating and wireless electronic transmission components.The system can undergo conformal deformation with human skin and achieve high-fidelity capture of biological information originating from human body motions to prevent diseases(such as Parkinson’s disease).In addition,this system also displays superior sensitivity and accu-racy in detecting subtle pressure changes in vivo during heartbeats,respiration,and diaphragm movement.Therefore,elastic FF crystal fibers hold great potential for developing new flexible electromechanical sensors that are capable of conformal deformation with the human body,enabling precision medical diagnosis and efficient energy harvesting.
基金supported by National Natural Science Foundation of China(No.12474213,52032005,82225012,52325204,and U22A20254)National Key Research and Development Program of China(No.2024YFF1400700)supported by Wuzhen Laboratory,and Deutsche Forschungsgemeinschaft(No.414311761).
文摘Piezoelectric materials are capable of converting between mechanical and electrical energy,and are suitable for sensing,actuating and energy harvesting.While most conventional piezoelectric materials are brittle solids,flexible piezoelectric materials(FPM)retain functionality even under bending and stretching conditions.This characteristic has garnered increasing attention in recent years,particularly for wearable devices,where the ability to adapt to dynamic human movements is essential.In addition,wearable devices also demand excellent conformability,durability,and adaptability to miniaturization.FPM emerge as a promising solution that meet all these requirements.This review thus aims to offer a comprehensive summary of recent advances in the field of FPM,including piezoelectric polymers,composites,and inorganic flexible films.We introduce and categorize the specific features of these materials and highlight their emerging applications in electronic devices,and comment on the prospect of FPM as well as their potential challenges.
基金The authors I.C.and N.P.would like to thank the Portuguese foundation FCT through their grants SFRH/BPD/81032/2011 and SFRH/BPD/71289/2010,respectivelyFinancial support from FCT through the projects PTDC/FIS/108025/2008 and PTDC/CTM-CER/115085/2009 is also acknowledged.
文摘In the last few years,there has been tremendous effort to develop lead-free ferroelectric ceramics with high piezoelectric properties by various doping and alloying routes.Several material systems have been explored,however,no prominent alternative to the versatile lead zirconate titanate(PZT)system has been found yet.Despite the achieved improvement in piezoelectric properties,there are problems in the synthesis,processing and poling of the sintered ceramics.Various processing techniques including microwave,hydrothermal,solgel,Pechini and spark plasma sintering have been used to overcome the drawbacks related to synthesis issues.In this paper,an attempt is made to review recent developments on lead-free piezo materials emphasizing their preparation,structureproperty relations,and consequent physical properties.In this context,both compositional and structural engineering approaches to achieve acceptable piezoelectric properties in lead-free materials are discussed.Piezoelectric properties of the most promising lead-free compositions/families including titanates,alkaline niobates and bismuth perovskites and their solid solutions,along with non-perovskites such as bismuth layer-structured ferroelectrics are reviewed in detail.A brief coverage of the recent developments in the area of piezoelectric energy harvesting is also encompassed.
基金The authors acknowledge the support of the Australian Research Council through the ARC Research Hub for Advanced Manufacturing of Medical Devices(IH150100024).
文摘Flexible piezoelectrics realise the conversion between mechanical movements and electrical power by conformally attaching onto curvilinear surfaces,which are promising for energy harvesting of biomedical devices due to their sustainable body movements and/or deformations.Developing secondary functions of flexible piezoelectric energy harvesters is becoming increasingly significant in recent years via aiming at issues that cannot be addressed or mitigated by merely increasing piezoelectric efficiencies.These issues include loose interfacial contact and pucker generation by stretching,power shortage or instability induced by inadequate mechanical energy,and premature function degeneration or failure caused by fatigue fracture after cyclic deformations.Herein,the expedient secondary functions of flexible piezoelectrics to mitigate above issues are reviewed,including stretchability,hybrid energy harvesting,and self-healing.Efforts have been devoted to understanding the state-of-the-art strategies and their mechanisms of achieving secondary functions based on piezoelectric fundamentals.The link between structural characteristic and function performance is unravelled by providing insights into carefully selected progresses.The remaining challenges of developing secondary functions are proposed in the end with corresponding outlooks.The current work hopes to help and inspire future research in this promising field focusing on developing the secondary functions of flexible piezoelectric energy harvesters.
文摘Na_(0.5)Bi_(0.5)TiO_(3)-based lead-free piezoelectrics are considered for potential replacement of the lead-based commercial piezoceramics in high-power transducer applications.We have examined the role of grain size in influencing the structural-polar inhomogeneity of stoichiometric and off-stoichiometric Na_(0.5)Bi_(0.5)TiO_(3)(NBT),and its morphotropic-phase-boundary(MPB)derivative 0.94Na_(0.5)Bi_(0.5)TiO_(3)-0.06BaTiO_(3)(NBT-6BT).Our study reveals that size effect comes into play in these systems on a very large length scale(on the scale of microns)considerably affecting its global structure and properties.
基金supported by Korea Evaluation Institute of Industrial Technology(KEIT)grant funded by the Korea Government(MOTIE)(RS-2022-00154720,Technology Innovation Program Development of next-generation power semiconductor based on Si-on-SiC structure)the National Research Foundation of Korea(NRF)by the Korea government(RS-2023-NR076826)Global-Learning&Academic Research Institution for Master's·PhD students,and Postdocs(LAMP)Program of the National Research Foundation of Korea(NRF)by the Ministry of Education(No.RS-2024-00443714).
文摘Improving device efficiency is fundamental for advancing energy harvesting technology,particularly in systems designed to convert light energy into electrical output.In our previous studies,we developed a basic structure light pressure electric generator(Basic-LPEG),which utilized a layered configuration of Ag/Pb(Zr,Ti)O_(3)(PZT)/Pt/GaAs to generate electricity based on light-induced pressure on the PZT.In this study,we sought to enhance the performance of this Basic-LPEG by introducing Ag nanoparticles/graphene oxide(AgNPs/GO)composite units(NP-LPEG),creating upgraded harvesting device.Specifically,by depositing the AgNPs/GO units twice onto the Basic-LPEG,we observed an increase in output voltage and current from 241 mV and 3.1μA to 310 mV and 9.3μA,respectively,under a solar simulator.The increase in electrical output directly correlated with the intensity of the light pressure impacting the PZT,as well as matched the Raman measurements,finite-difference time-domain simulations,and COMSOL Multiphysics Simulation.Experimental data revealed that the enhancement in electrical output was proportional to the number of hot spots generated between Ag nanoparticles,where the electric field experienced substantial amplification.These results underline the effectiveness of AgNPs/GO units in boosting the light-induced electric generation capacity,thereby providing a promising pathway for high-efficiency energy harvesting devices.
基金supported by the National Key Research and Development Program of China(No.2024YFB3212901)National Natural Science Foundation of China(12072189)the Medicine and Engineering Interdisciplinary Research Fund of Shanghai Jiao Tong University(No.YG2025ZD05)。
文摘Pipelines are extensively used in environments such as nuclear power plants,chemical factories,and medical devices to transport gases and liquids.These tubular environments often feature complex geometries,confined spaces,and millimeter-scale height restrictions,presenting significant challenges to conventional inspection methods.Here,we present an ultrasonic microrobot(weight,80 mg;dimensions,24 mm×7 mm;thickness,210μm)to realize agile and bidirectional navigation in narrow pipelines.The ultrathin structural design of the robot is achieved through a high-performance piezoelectric composite film microstructure based on MEMS technology.The robot exhibits various vibration modes when driven by ultrasonic frequency signals,its motion speed reaches81 cm s-1 at 54.8 k Hz,exceeding that of the fastest piezoelectric microrobots,and its forward and backward motion direction is controllable through frequency modulation,while the minimum driving voltage for initial movement can be as low as 3 VP-P.Additionally,the robot can effortlessly climb slopes up to 24.25°and carry loads more than 36 times its weight.The robot is capable of agile navigation through curved L-shaped pipes,pipes made of various materials(acrylic,stainless steel,and polyvinyl chloride),and even over water.To further demonstrate its inspection capabilities,a micro-endoscope camera is integrated into the robot,enabling real-time image capture inside glass pipes.
基金supported by the National Natural Science Foundation of China(Nos.52373235 and 52573322)the National Natural Science Foundation of Hubei Province of China(No.2024AFB568).
文摘Repolarizing tumor-associated macrophages(TAMs)toward the proinflammatory M1 phenotype represents a promising strategy to reverse the immunosuppressive tumor microenvironment(TME)and enhance antitumor immunotherapy.Recent studies have demonstrated that exogenous electrical stimulation can effectively repolarize TAMs toward the M1 phenotype.However,conventional electrical stimulation methods,relying on invasive implanted electrodes,are restricted to targeting localized tumor regions and pose inherent risks to patients.Notably,biological neural networks,distributed systems of interconnected neurons,can naturally permeate tissues and orchestrate cellular activities with high spatial efficiency.Inspired by this natural system,we developed a global in situ electric field network using piezoelectric BaTiO_(3)nanoparticles.Upon ultrasound stimulation,the nanoparticles generate a wireless electric field throughout the TME.In addtion,their nanoscale size enables them to function as synthetic“neurons”,allowing for uniform penetration throughout the tumor tissue and inducing significant repolarization of TAMs via the Ca^(2+)influx-activated nuclear factor-kappa B(NF-κB)signaling pathway.The repolarized M1 TAMs restore anti-tumor immunostimulatory functions and secrete key proinflammatory cytokines(e.g.,tumor necrosis factor-alpha(TNF-α)and interleukin-1 beta(IL-1β)),which enhance immunostimulation within the TME and directly contribute to tumor cell elimination.Remarkably,this strategy achieved robust in vivo tumor growth inhibition with excellent biosafety in a 4T1 breast tumor model.Overall,this work establishes a non-invasive,wireless electric field platform capable of globally repolarizing TAMs,offering a safe and efficient strategy to advance cancer immunotherapy and accelerate the clinical translation of bioelectronic therapies.
基金research engineer Roger Sagdahl,Chalmers University of Technology,for valuable discussions on energy harvesting.CHESS(supported by the NSF&NIH/NIGMS via NSF award DMR-1332208)is gratefully acknowledged for providing experimental time for WAXS measurementsFinancial support from the Swedish Foundation for Strategic Research(SSF)through grant no.SBE13-0086+1 种基金the Knut and Alice Wallenberg Foundation through a Wallenberg Academy Fellowshipthe European Research Council(ERC)under grant agreement no.637624 is gratefully acknowledged.
文摘Recent advances in ubiquitous low-power electronics call for the development of light-weight and flexible energy sources.The textile format is highly attractive for unobtrusive harvesting of energy from e.g.,biomechanical movements.Here,we report the manufacture and characterisation of fully textile piezoelectric generators that can operate under wet conditions.We use a weaving loom to realise textile bands with yarns of melt-spun piezoelectric microfibres,that consist of a conducting core surrounded byβ-phase poly(vinylidene fluoride)(PVDF),in the warp direction.The core-sheath constitution of the piezoelectric microfibres results in a—for electronic textiles—unique architecture.The inner electrode is fully shielded from the outer electrode(made up of conducting yarns that are integrated in the weft direction)which prevents shorting under wet conditions.As a result,and in contrast to other energy harvesting textiles,we are able to demonstrate piezoelectric fabrics that do not only continue to function when in contact with water,but show enhanced performance.The piezoelectric bands generate an output of several volts at strains below one percent.We show that integration into the shoulder strap of a laptop case permits the continuous generation of four microwatts of power during a brisk walk.This promising performance,combined with the fact that our solution uses scalable materials and well-established industrial manufacturing methods,opens up the possibility to develop wearable electronics that are powered by piezoelectric textiles.
基金supported by the National Basic Research Program of China(Grant No.2015CB351900)National Natural Science Foundation of China(Grant Nos.11222220,11320101001,11090331 and 11227801)Tsinghua University Initiative Scientific Research Program
文摘As rapid development in wearable/implantable electronic devices benefit human life in daily health monitoring and disease treatment medically, all kinds of flexible and/or stretchable electronic devices are booming, together with which is the demanding of energy supply with similar mechanical property. Due to its ability in converting mechanical energy lying in human body into electric energy, energy harvesters based on piezoelectric materials are promising for applications in wearable/implantable device's energy supply in a renewable, clean and life-long way. Here the mechanics of traditional piezoelectrics in energy harvesting is reviewed, including why piezoelectricity is the choice for minor energy harvesting to power the implantable/wearable electronics and how. Different kinds of up to date flexible piezoelectric devices for energy harvesting are introduced, such as nanogenerators based on Zn O and thin and conformal energy harvester based on PZT. A detailed theoretical model of the flexible thin film energy harvester based on PZT nanoribbons is summarized, together with the in vivo demonstration of energy harvesting by integrating it with swine heart. Then the initial researches on stretchable energy harvesters based on piezoelectric material in wavy or serpentine configuration are introduced as well.
基金supported by the National Natural Science Foundation of China(Grant Nos.12135019 and 52202154)the 2115 Talent Development Program of China Agricultural University,the Scientific Research Start-up Fund for Outstanding Talent of China Agricultural University,Chinese Universities Scientific Fund,and High-performance Computing Platform of China Agricultural University。
文摘Piezoelectric ceramics provide high strain and large driving forces in actuators.A large electrostrain can be realized by the introduction of point defects such as vacancies,interstitial defects,and substitution defects.With Mn doping,a significant increase in the reversible electrostrain from 0.05%to 0.17%could be achieved in potassium niobite lead-free piezoelectric ceramics.The origins of the large electrostrain were analyzed via in situ X-ray diffraction(XRD)under an electric field.The electrostrain and other typical electrical properties of the samples were measured at various temperatures,which enabled the ceramics to perform under a very wide temperature range,such as−80–130℃ for the 0.5 mol%Mn-doped sample with low dielectric loss(≤0.02).More importantly,combined with characterizations of the defect behavior by thermally stimulated depolarization current(TSDC),the failure mechanisms of electrostrain in a hightemperature environment could be revealed,which was associated with synergistic damage to the defects caused by the electric field and high temperature.The results can provide good ideas and a basis for the design of piezoelectric materials with good electrostrain stability over a wide temperature range.
基金Project supported by the Key Research and Develop Projects in Gansu Province(Grant No.23YFGA0002)the project funding of Audiowell Electronics(Guangdong)Co.,Ltd.
文摘Piezoelectric ceramic materials are important components of piezoelectric buzzers,where the parameter of inverse piezoelectric coefficient(d_(33)^(*))plays a decisive role in the performance of the buzzer.Here,we report the manufacture and performance of a lead-free ceramic-based(0.96(K_(0.5)Na_(0.5))(Nb_(0.96)Sb_(0.04))O_(3)-0.04(Bi_(0.5)Na_(0.5))ZrO_(3)-1 mol%Al_(2)O_(3),abbreviated as KNNS-BNZ-1 mol%Al_(2)O_(3))piezoelectric buzzer and compare it with commercial(PbZr_(0.5)Ti_(0.5)O_(3),abbreviated as PZT)ceramics.Briefly,KNN-based ceramics have a typical perovskite structure and piezoelectric properties of d_(33)=480 pC/N,k_(p)=0.62 and d_(33)^(*)=830 pm/V,compared to d_(33)=500 pC/N,k_(p)=0.6 and d_(33)^(*)=918 pm/V of the commercial PZT-4 ceramics.Our results show that the KNNS-BNZ-1 mol%Al_(2)O_(3)ceramics have a similar sound pressure level performance over the testing frequency range to commercial PZT ceramics(which is even better in the 3-4 kHz range).These findings highlight the great application potential of KNN-based piezoelectric ceramics.
基金financially supported by the National Key R&D Program of China(Grant No.2022YFC2204203)the National Natural Science Foundation of China(Grant No.52305107)。
文摘Precision actuation is a foundational technology in high-end equipment domains,where stroke,velocity,and accuracy are critical for processing and/or detection quality,precision in spacecraft flight trajectories,and accuracy in weapon system strikes.Piezoelectric actuators(PEAs),known for their nanometer-level precision,flexible stroke,resistance to electromagnetic interference,and scalable structure,have been widely adopted across various fields.Therefore,this study focuses on extreme scenarios involving ultra-high precision(micrometer and beyond),minuscule scales,and highly complex operational conditions.It provides a comprehensive overview of the types,working principles,advantages,and disadvantages of PEAs,along with their potential applications in piezo-actuated smart mechatronic systems(PSMSs).To address the demands of extreme scenarios in high-end equipment fields,we have identified five representative application areas:positioning and alignment,biomedical device configuration,advanced manufacturing and processing,vibration mitigation,micro robot system.Each area is further divided into specific subcategories,where we explore the underlying relationships,mechanisms,representative schemes,and characteristics.Finally,we discuss the challenges and future development trends related to PEAs and PSMSs.This work aims to showcase the latest advancements in the application of PEAs and provide valuable guidance for researchers in this field.
基金National Natural Science Foundation of China(No.52373281)National Energy-Saving and Low-Carbon Materials Production and Application Demonstration Platform Program,China(No.TC220H06N)。
文摘The research,fabrication and development of piezoelectric nanofibrous materials offer effective solutions to the challenges related to energy consumption and non-renewable resources.However,enhancing their electrical output still remains a significant challenge.Here,a strategy of inducing constrained phase separation on single nanofibers via shear force was proposed.Employing electrospinning technology,a polyacrylonitrile/polyvinylidene difluoride(PAN/PVDF)nanofibrous membrane was fabricated in one step,which enabled simultaneous piezoelectric and triboelectric conversion within a single-layer membrane.Each nanofiber contained independent components of PAN and PVDF and exhibited a rough surface.The abundant frictional contact points formed between these heterogeneous components contributed to an enhanced endogenous triboelectric output,showcasing an excellent synergistic effect of piezoelectric and triboelectric response in the nanofibrous membrane.Additionally,the component mass ratio influenced the microstructure,piezoelectric conformation and piezoelectric performance of the PAN/PVDF nanofibrous membranes.Through comprehensive performance comparison,the optimal mass ratio of PAN to PVDF was determined to be 9∶1.The piezoelectric devices made of the optimal PAN/PVDF nanofibrous membranes with rough nanofiber surfaces generated an output voltage of 20 V,which was about 1.8 times that of the smooth one at the same component mass ratio.The strategy of constrained phase separation on the surface of individual nanofibers provides a new approach to enhance the output performance of single-layer piezoelectric nanofibrous materials.
基金supported by the research projects AP23486880 from the Ministry of Higher EducationScience of the Republic of Kazakhstan and 111024CRP2010,20122022FD4135 from Nazarbayev University.
文摘Recycling plastic waste into triboelectric nanogenerators(TENGs)presents a sustainable approach to energy harvesting,self-powered sensing,and environmental remediation.This study investigates the recycling of polyvinyl chloride(PVC)pipe waste polymers into nanofibers(NFs)optimized for TENG applications.We focused on optimizing the morphology of recycled PVC polymer to NFs and enhancing their piezoelectric properties by incorporating ZnO nanoparticles(NPs).The optimized PVC/0.5 wt%ZnO NFs were tested with Nylon-6 NFs,and copper(Cu)electrodes.The Nylon-6 NFs exhibited a power density of 726.3μWcm^(-2)—1.13 times higher than Cu and maintained 90%stability after 172800 cycles,successfully powering various colored LEDs.Additionally,a 3D-designed device was developed to harvest energy from biomechanical movements such as finger tapping,hand tapping,and foot pressing,making it suitable for wearable energy harvesting,automatic switches,and invisible sensors in surveillance systems.This study demonstrates that recycling polymers for TENG devices can effectively address energy,sensor,and environmental challenges.
基金supported by the National Key Research and Development Program of China(No.2023YFF0720700)the National Natural Science Foundation of China(Nos.52032010 and 52272120)the Central Government Funds of Guiding Local Scientific and Technological Development for Sichuan Province(No.2022ZYD0018).
文摘The types of dopants lead to distinctive microstructural evolution behavior and physical properties in materials.In this study,the effect of stoichiometric and non-stoichiometric Mn modification,namely Pb(Mn_(1/3) Nb_(2/3))O_(3)(PMnN)and MnO_(2),on the microstructure and properties of Pb(Yb_(1/2) Nb_(1/2))O_(3)-PbZrO_(3)-PbTiO_(3)(PYN-PZT)piezoelectric ceramics are systematically investigated.It was found that stoichiometric PMnN modification inhibits the grain growth while non-stoichiometric MnO_(2) modification promotes it,and thus the former yields stronger high-power characteristics(higher internal bias field Ei and larger mechanical quality factor Q_(m))than the latter.Specifically,with an equivalent amount of Mn modifica-tion(2 mol%),PMnN and MnO_(2) modification PYN-PZT ceramics exhibit significantly different values for average grain size(1.21μm vs.14.12μm),Ei(8.5 kV/cm vs.5 kV/cm),and Qm(2376 vs.1134).To further evaluate high-power performance,the vibration velocity v of these two modified PYN-PZT under high driving conditions was measured.Under an AC electric field of 3.5 V/mm,the PYN-PZT+6PMnN ceram-ics exhibit a v of up to 0.95 m s^(−1),larger than both MnO2-doped PYN-PZT(0.72 m s^(−1))and unmodified PYN-PZT ceramics(0.1 m s^(−1)),and far outperformance than both PZT-4 and PZT-8 ceramics.Furthermore,to elucidate the origin of the exceptional high-power performance of PMnN-modified PYN-PZT,we per-formed phase-field simulations revealing a pinning effect of the grain boundary on domain wall motion.Consequently,the small grain size(high grain boundary density)in PMnN-modified PYN-PZT exhibits a strong pinning effect,resulting in a large Q_(m) and outstanding high-power performance.
基金financially supported by the National Natural Science Foundation of China(No.22272151)Public Welfare Technology Application Research Project of Jinhua City,China(No.2023-4-022)。
文摘BiVO_(4)porous spheres modified by ZnO were designed and synthesized using a facile two-step method.The resulting ZnO/BiVO_(4)composite catalysts have shown remarkable efficiency as piezoelectric catalysts for degrading Rhodamine B(RhB)unde mechanical vibrations,they exhibit superior activity compared to pure ZnO.The 40wt%ZnO/BiVO_(4)heterojunction composite displayed the highest activity,along with good stability and recyclability.The enhanced piezoelectric catalytic activity can be attributed to the form ation of an I-scheme heterojunction structure,which can effectively inhibit the electron-hole recombination.Furthermore,hole(h+)and superoxide radical(·O_(2)^(-))are proved to be the primary active species.Therefore,ZnO/BiVO_(4)stands as an efficient and stable piezoelectric catalyst with broad potential application in the field of environmental water pollution treatment.
基金supported by the National Natural Science Foundation of China(Grant Nos.52272103 and 52072010)Beijing Natural Science Foundation(Grant Nos.2242029 and JL23004).
文摘High temperature piezoelectric energy harvester(HTPEH)is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors.However,simultaneously excellent performances,including high figure of merit(FOM),insulation resistivity(ρ)and depolarization temperature(Td)are indispensable but hard to achieve in lead-free piezoceramics,especially operating at 250°C has not been reported before.Herein,well-balanced performances are achieved in BiFeO3–BaTiO3 ceramics via innovative defect engineering with respect to delicate manganese doping.Due to the synergistic effect of enhancing electrostrictive coefficient by polarization configuration optimization,regulating iron ion oxidation state by high valence manganese ion and stabilizing domain orientation by defect dipole,comprehensive excellent electrical performances(Td=340°C,ρ250°C>10^(7)Ωcm and FOM_(250°C)=4905×10^(–15)m^(2)N^(−1))are realized at the solid solubility limit of manganese ions.The HT-PEHs assembled using the rationally designed piezoceramic can allow for fast charging of commercial electrolytic capacitor at 250°C with high energy conversion efficiency(η=11.43%).These characteristics demonstrate that defect engineering tailored BF-BT can satisfy high-end HT-PEHs requirements,paving a new way in developing selfpowered wireless sensors working in HT environments.
基金financially supported by the National Key Research and Development Program of China(No.2022YFA1205300 and No.2022YFA1205304)the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(SL2022ZD103).
文摘Monitoring minuscule mechanical signals,both in magnitude and direction,is imperative in many application scenarios,e.g.,structural health monitoring and robotic sensing systems.However,the piezoelectric sensor struggles to satisfy the requirements for directional recognition due to the limited piezoelectric coefficient matrix,and achieving sensitivity for detecting micrometer-scale deformations is also challenging.Herein,we develop a vector sensor composed of lead zirconate titanate-electronic grade glass fiber composite filaments with oriented arrangement,capable of detecting minute anisotropic deformations.The as-prepared vector sensor can identify the deformation directions even when subjected to an unprecedented nominal strain of 0.06%,thereby enabling its utility in accurately discerning the 5μm-height wrinkles in thin films and in monitoring human pulse waves.The ultra-high sensitivity is attributed to the formation of porous ferroelectret and the efficient load transfer efficiency of continuous lead zirconate titanate phase.Additionally,when integrated with machine learning techniques,the sensor’s capability to recognize multi-signals enables it to differentiate between 10 types of fine textures with 100%accuracy.The structural design in piezoelectric devices enables a more comprehensive perception of mechanical stimuli,offering a novel perspective for enhancing recognition accuracy.
