Piezoelectric Film Research Articles

Flexible all-inorganic Sm-doped PMN-PT film with ultrahigh piezoelectric coefficient for mechanical energy harvesting, motion sensing, and human-machine interaction

In the era of artificial intelligence and the internet of things, the emergence of flexible MICAtronics, heterostructures made by van der Waals epitaxy on layered mica, has attracted great research interest due to applications in the fields of flexible ferroelectric memory, dielectric capacitors, and others, but less effort has been dedicated to the realization of flexible piezoelectric inorganic films for energy harvesters and sensors. In this work, an all-inorganic transparent Sm-doped Pb(Mg1/3Nb2/3)O3-PbTiO3 (Sm:PMN-PT) film has been successfully grown on Mica substrate via a simple one-step sol-gel process. The flexible film shows an ultrahigh piezoelectric coefficient d33 of 380 pm V−1 owing to the enhanced local structural heterogeneity and the weak substrate clamping effect. Simultaneously, superior flexibility is realized without sacrificing its electrical performance, as reflected by withstanding a small radius of curvature of 2 mm and even 103 mechanical bending cycles. Utilizing this Sm:PMN-PT film, the fabricated device exhibits an excellent energy harvesting performance with output voltage of 6 V, current density of 150 μA cm−2, andultrahigh force sensitivity of 5.86 V N−1. Besides, it also possesses a certain temperature resistance and favorable hydrophobicity. In practical applications, it can not only be employed to monitor body motions, including finger pressing, hand tapping, foot stepping, finger/wrist bending, and hand grasping, but also serves as a tactile sensor to record the touch of a finger to unlock a smartphone. This work demonstrates that the flexible PMN-PT based film on Mica substrate has full application potential in mechanical energy harvesting, motion sensing, and human-machine interaction.

Experimental investigation into the sensitivity of elastically coated piezoelectric polyvinylidene fluoride films to an impact force

This paper presents an experimental study on the effect of an elastic coating on the sensitivity to an impact force on a polyvinylidene fluoride (PVDF) film by using a model consisting of a top mass, a coated/uncoated PVDF film, and a base block. The sensitivity of the PVDF film is determined by measuring the voltage outputs from the PVDF film and an impact hammer, which is used to excite the top mass. The effects of the constraints at the top and bottom surfaces of an uncoated PVDF film on the sensitivity are examined first. Experimentally, the shear-free and perfectly bonded constraints are approximated by applying oil and epoxy glue to the interfaces between the PVDF film and the top mass/base block. The sensitivities of the PVDF film for these two constraints are determined analytically, thus explaining the roles of the stress components in the thickness and in-plane directions of the film in generating the voltage outputs. The approximated shear-free boundary condition using oil at the interface allows an experimental determination of the piezoelectric voltage constant of the PVDF film in the poling direction. Rubber and polyurethane are used for constructing the coated PVDF films. Even a thin layer of elastic coating is capable of significantly increasing the sensitivity of the PVDF film. For example, 3 mm rubber layers allow a 27 dB increase in the low-frequency sensitivity. A system including an elastically coated PVDF film provides an additional 10 dB increase at frequencies close to its first resonance frequency, resulting in a total 37 dB increase in the system sensitivity. The increased sensitivity may be explained as being due to the increased shear force between the elastic material and PVDF film as the thickness of the elastic layer increases. The dominating effect of the shear force is illustrated by the experimental and finite-element analysis as the thickness of the rubber coating gradually increases. The high rate of increase of the sensitivity as a function of rubber thickness can be observed when the thickness is under 0.8 mm.

AlScN films prepared by alloy targets and SAW device characteristics

In this paper, we reported a surface acoustic wave (SAW) device prepared and optimized by piezoelectric films containing AlN, AlScN (Sc-20 at%) and AlScN (Sc-30 at%) by reactive magnetron sputtering using Al and AlSc alloy targets. We calculated the material intrinsic electromechanical coupling coefficient kt2 of AlScN (Sc-20 at%) and AlScN (Sc-30 at%) which are much better than AlN. It can be explained by the lattice softening. Furtherly, the results were confirmed by transmission electron microscopy (TEM) observation of the microstructure. Then the SAW devices based on three thin films were tested by vector network analysis obtaining the device equivalent electromechanical coupling coefficient keff2. The value of AlScN (Sc-20 at%) keff2, which equals to 1.94%, is higher than that of AlN and AlScN (Sc-30 at%) while the value of AlScN (Sc-30 at%) kt2 is higher than that of others. It is shown in our study that the crystallinity and orientation of the material still have a greater impact on keff2 but it does not have influence on kt2 in the actual device preparation process.

Highly (00l)-textured BiFeO3 thick films integrated on stainless steel foils with an optimized piezoelectric performance

Piezoelectric BiFeO3 films were successfully prepared on 304 stainless steel (SS) foils via RF-magnetron sputtering at 450 °C. By adopting a LaNiO3/Pt/Ti tri-layer bottom electrode, a predominant (100)-orientation and a better crystalline morphology were achieved in the BiFeO3 film, resulting in better ferroelectric and dielectric properties targeted for piezoelectric applications than those directly grown on SS or LaNiO3/SS. These properties include a large remnant polarization (Pr~68 μC/cm2), a large coercive field (Ec~241 kV/cm) and a sizable self-bias (Ebi~ 158 kV/cm), as well as a low dielectric constant and a reduced dielectric loss (εr≤200 and tan δ ≤ 0.026 in 1 kHz-1 MHz). Based on this optimal BiFeO3-SS heterostructure, large converse and direct transverse piezoelectric coefficients |e31,f| ~ 1.7 C/m2 and 1.07 C/m2 were achieved in prototype piezoelectric actuator and energy harvester structures, respectively. These results suggest that BiFeO3-SS heterostructures have a great potential for applications in lead-free, metal-based piezoelectric micro-electro- mechanical systems (piezo-MEMS).

Temperature-induced potential barriers in piezoelectric semiconductor films through pyroelectric and thermoelastic couplings and their effects on currents

We study temperature effects in piezoelectric semiconductor thin films through pyroelectric and thermoelastic as well as piezoelectric couplings. Two-dimensional equations based on the macroscopic theory of piezoelectric semiconductors for extensional deformations of the films are used. A p-type ZnO film with an in-plane c-axis is analyzed. It is shown through a linear and theoretical analysis that a local temperature change produces a pair of a potential barrier and a well in the film. A nonlinear numerical analysis is then performed when a voltage is also applied, showing that the potential barrier blocks the in-plane motion of the holes and thus affects the current density distribution. The effects of various physical and geometric parameters are examined. The results obtained provide the theoretical foundation for thermally manipulating currents in piezoelectric semiconductor films for piezotronic applications.

Rayleigh and shear-horizontal surface acoustic waves simultaneously generated in inclined ZnO films for acoustofluidic lab-on-a-chip

There are significant challenges in controlling uniformity of crystal inclination angles, growth orientations and film thicknesses to generate dual-mode surface acoustic waves (e.g., Rayleigh ones and shear-horizontal ones) for lab-on-a-chip applications. In this study, we demonstrate large area (up to three inches) and uniformly inclined piezoelectric ZnO films, sputtering-deposited on silicon using a glancing angle deposition method. Characterization using X-ray diffraction showed that the inclined ZnO films have an average crystal inclination angle of 29.0°, apart from the vertical (0002) orientation, at a substrate tilting angle of 30o. Reflection signals of ZnO/Si surface acoustic wave devices clearly show the generations of both shear horizontal surface acoustic waves and Rayleigh waves. The Rayleigh waves enable efficient acoustofluidic functions including streaming and transportation of sessile droplets. Excitation direction of Rayleigh waves on the acoustofluidics versus the inclined angle direction has apparent influences on the acoustofluidic performance due to the anisotropic microstructures of the inclined films. The same device has been used to demonstrate biosensing of biotin/streptavidin interactions in a liquid environment using the shear-horizontal surface acoustic waves, to demonstrate its potential for integration into a complete lab-on-a-chip device.

Development of MEMS Acoustic Sensor With Microtunnel for High SPL Measurement

The fabrication of piezoelectric ZnO-based micro-electro-mechanical systems (MEMS) acoustic sensor has been reported. The sensor structure consists of a piezoelectric ZnO film deposited between two Al electrodes on a thin silicon diaphragm. A microtunnel is fabricated in the sensor structure using novel approach. This microtunnel is used to protect the diaphragm and determine the lower cut-off frequency of device. The approach presented in this paper completely removed a serious problem of microtunnel blockages during fabrication of sensors. In the developed process, the acoustic sensor fabricated using silicon-on-insulator and the Pyrex glass wafers are diced separately with same chip dimensions. Finally, both Pyrex glass and acoustic sensor chips are fitted in a jig for alignment and then anodically bonded. In reference to microtunnel blockages, the yield of the present technique is obtained as almost 100%. Also, the technique will serve as a cost-effective alternative to the present practice. The developed technique can also be used in manufacturing of similar devices where the microtunnels or microchannels are required in device structure. The technological development is supported by extensive atomic force microscopy (AFM), field emission scanning electron microscopy, Raman spectroscopy, and X-ray diffraction studies of ZnO film; glass-to-silicon bond strength measurement; resonance frequency measurement by laser doppler vibrometer; response characterization of the fabricated sensor, and scanning electron microscopy of microtunnel mouth to demonstrate the feasibility and yield of the process.

Development and Characterization of ZnO Piezoelectric Thin Film Sensors on GH4169 Superalloy Steel Substrate by Magnetron Sputtering.

At present, piezoelectric sensors are primarily applied in health monitoring areas. They may fall off owing to the adhesive’s durability, and even damage the monitored equipment. In this paper, a piezoelectric film sensor (PFS) based on a positive piezoelectric effect (PPE) is presented and a ZnO film is deposited on a GH4169 superalloy steel (GSS) substrate using magnetron sputtering. The microstructure and micrograph of ZnO piezoelectric thin films were analyzed by an X-ray diffractometer (XRD), energy dispersive spectrometer (EDS), scanning electron microscope (SEM), and atomic force microscope (AFM). The results showed that the surface morphology was dense and uniform and had a good c-axis-preferred orientation. According to the test results of five piezoelectric sensors, the average value of the longitudinal piezoelectric coefficient was 1.36 pC/N, and the average value of the static calibration sensitivity was 19.77 mV/N. We selected the sensor whose parameters are closest to the average value for the dynamic test experiment and we drew the output voltage response curve of the piezoelectric film sensor under different loads. The measurement error was 4.03% when repeating the experiment six times. The research achievements reveal the excellent performance of the piezoelectric film sensor directly deposited on a GH4169 superalloy steel substrate. This method can reduce measurement error caused by the adhesive and reduce the risk of falling off caused by the aging of the adhesive, which provides a basis for the research of smart bolts and guarantees a better application in structural health monitoring (SHM).

Orientation dependent intrinsic and extrinsic contributions to the piezoelectric response in lead-free (Na0.5K0.5)NbO3 based films

The intrinsic and extrinsic contributions to the piezoelectric response are deeply dependent on the crystallographic orientation in the thin films. Herein, (100), (110) and (111)-oriented (Na0.5K0.5)NbO3 (KNN) based lead-free piezoelectric films are synthesized by a sol-gel method. The dielectric, ferroelectric and piezoelectric properties of the KNN-based films at the rhombohedral-orthorhombic (R-O) phase boundary are investigated with the focus on the influence of the film orientation. The maximum piezoelectric response is obtained in the (100)-oriented film, resulting from the extrinsic contribution stimulated by the external electric field, although the (110) and (111)-oriented films have the higher dielectric constant and remnant polarization. There are more varied ways of domain switching and domain configuration under the external electric field in (100)-oriented film, leading to the higher extrinsic contribution to the piezoelectric response. The study of the orientation effect on the piezoelectric response can shed light on the exploration of optimal piezoelectricity by tailoring the preferred orientation in KNN-based lead-free films.

Dimensional Effects of Polymer Piezoelectric Films for Wind Energy Harvesting

Abstract Arrays of flexible polymer piezoelectric film cantilevers that mimic grass or leaves is a prospective idea for harvesting wind energy in urban areas, where the use of traditional technologies is problematic due to low wind velocities. Conversion of this idea into an economically attractive technology depends on various factors including the shape and dimensions of individual films to maximize generated power and to minimize associated costs of production, operation, and maintenance. The latter requirement can be satisfied with rectangular films undergoing flutter in ambient air. Flexible piezoelectric films that displace due to low forces and can convert mechanical energy into electrical energy are ideal for this application. The goal of the presented study is to determine the key dimensions of the piezoelectric film to enhance generated power within the wind range characteristic for urban areas from 1.3 to 7.6 m/s. For this purpose, experiments were conducted in a wind tunnel using piezoelectric polymer films of polyvinylidine fluoride with the length, width, and thickness varying in the ranges of 32–150, 16–22, and 40–64 μm, respectively. Voltage and power outputs for individual samples were measured at wind speeds ranging from 0.5 to 16.5 m/s. Results demonstrated that a single film could produce up to 0.74 nW and that the optimal film dimensions are 63 mm × 22 mm × 40 μm (from considered samples) for the wind energy harvesting in urban areas. Further improvement in power production can be expected when using films with reduced thickness, low elastic modulus, and increased length, and by assembling films in arrays.

Resonating AlN-thin film MEMS mirror with digital control

Piezoelectrically actuated resonant micromirrors were designed to meet the light detection and ranging (LiDAR) system requirements. Key features were a 3-mm mirror aperture, a 40-deg field of view, and a 50-Hz refresh rate. The presented micromirror provides biaxial symmetrical beam steering with ±12.7 deg mechanical tilt angle, resulting in a 50-deg field of view with an adjustable Lissajous XY-scanning pattern for a forward-looking LiDAR system. The mirrors were fabricated using silicon on insulator wafers, and actuation was based on piezoelectric aluminium nitride thin film. The mirrors were vacuum packaged for high-quality factor resonator operation. The device design contained eight separate piezoelectric aluminium nitride elements arranged as differential pairs for each axis, where each actuator was equipped with a sensing element providing a mechanically coupled electrical feedback signal. The piezoelectric elements connected as actuators required only minimal power and were directly compatible with CMOS low-voltage logic, which eases integration to driving digital systems. The sense elements are used to monitor phase, amplitude, and frequency. A digital control system connected to each of these elements provides accurate frequency and phase control of independent orthogonal resonators, permitting control of the X and Y amplitudes and the refresh rate of the Lissajous pattern.

Performance of a Lever‐Gear Type Piezoelectric Energy Harvester for Collecting Pedestrian Energy

As pedestrian‐induced energy exists widely in our daily life, the collection of pedestrian energy has attracted increasing attention. Herein, a novel energy harvester is developed to capture the kinetic energy of pedestrians. The mechanical part of the energy harvester mainly consists of a lever structure and a gear transmission component, which is used to convert the kinetic energy of pedestrians into that associated with the rotation of the device. Energy is collected by a polyvinylidene fluoride (PVDF) piezoelectric film. The performance of the harvester is tested under both indoor and outdoor conditions. Experimental results show that the maximum output voltage of the harvester with a single PVDF film is 1170 mV, and the harvester reaches the best output state when the load is 510 kΩ (acceleration 0.3 g (1 g = 9.8 m s−2), frequency 5 Hz) with the maximum output power equal to 1.41 μW. The harvester is then optimized by adding more PVDF films, and the improved device is found to possess a higher working efficiency, with the output voltage and power increased by 58.6% and 26%, respectively. Finally, outdoor tests are conducted, and the results further confirm the feasibility of using the device to harvest the ultralow frequency kinetic energy of pedestrians.

Piezoelectric-Fenton degradation and mechanism study of Fe2O3/PVDF-HFP porous film drove by flowing water

Piezocatalysis driven by a gentle force possesses broad application prospects for degrading organic pollutants, sterilisation, wound healing and tissue recovery. The flexible and industrially scalable poly(vinylidene fluoride) (PVDF) film is commonly used in piezocatalysis. However, under gentle force action, PVDF composite-based piezocatalysis is poor. Herein, a flexible porous film based on poly(vinylidene fluoride)-hexafluoro propylene (PVDF-HFP) is enhanced with Fenton fillers (α-Fe2O3 nanoparticles). α-Fe2O3 nanoparticles improve the piezoelectric catalysis performance of PVDF-HFP by the β-phase enhancement and provide Fe3+ to react with H2O2 generated by the piezoelectric film itself, leading to an additional Fenton reaction. Meanwhile, the Fe3+/Fe2+ cycle in the Fenton process accelerates under the piezoelectric field, promoting the Fenton reaction for 6.9% degradation improvement. The study on Fe2O3/PVDF-HFP porous film with the piezo–Fenton reaction under flowing water may help promote new piezocatalysis designs with high efficiency for self–powered environmental purification.

Thin films of the alpha-quartz Si_xGe_{1-x}O_2 solid solution

SiO_2 with the alpha-quartz structure is one of the most popular piezoelectrics. It is widely used in crystal oscillators, bulk acoustic wave (BAW) devices, surface acoustic wave (SAW) devices, and so on. GeO_2 can also be crystallized into the alpha-quartz structure and it has better piezoelectric properties, with higher piezoelectric coefficient and electromechanical coupling coefficients, than SiO_2. Experiments on bulk crystals and theoretical studies have shown that these properties can be tuned by varying the Si/Ge ratio in the Si_xGe_{1-x}O_2 solid solution. However, to the best of our knowledge, thin films of Si_xGe_{1-x}O_2 quartz have never been reported. Here we present the successful crystallization of Si_xGe_{1-x}O_2 thin films in the alpha-quartz phase on quartz substrates (SiO_2) with x up to 0.75. Generally, the films grow semi-epitaxially, with the same orientation as the substrates. Interestingly, the Si_{0.75}Ge_{0.25}O_2 composition grows fully strained by the quartz substrates and this leads to the formation of circular quartz domains with an ordered Dauphiné twin structure. These studies represent a first step towards the optimization of piezoelectric quartz thin films for high frequency (> 5 GHz) applications.

Highly sensitive and stretchable piezoelectric strain sensor enabled wearable devices for real-time monitoring of respiratory and heartbeat simultaneously

The World Health Organization has declared COVID-19 a pandemic. The demand for devices or systems to diagnose and track COVID-19 infections noninvasively not only in hospitals but also in home settings has led to increased interest in consumer-grade wearables. A common symptom of COVID-19 is dyspnea, which may manifest as an increase in respiratory and heart rates. In this paper, a novel piezoelectric strain sensor is presented for real-time monitoring of respiratory and heartbeat signals. A highly sensitive and stretchable piezoelectric strain sensor is fabricated using a piezoelectric film with a serpentine layout. The thickness of the patterned PVDF flexible piezoelectric strain sensor is only 168 μm, and the voltage sensitivity reaches 0.97 mV/μɛ. The effective modulus is 13.5 MPa, which allows the device to fit to the skin and detect the small strain exhibited by the human body. Chest vibrations are captured by the piezoelectric sensor, which produces an electrical output voltage signal conformally mapped with respiratory–cardiac activities. The separate heart activity and respiratory signals are extracted from the mixed respiratory–cardiac signal by an empirical mode decomposition data processing algorithm. By detecting vital signals such as respiratory and heart rates, the proposed device can aid early diagnosis and monitoring of respiratory diseases such as COVID-19.

Morphotropic Relaxor Boundary Construction Highly Boosts the Piezoelectric Properties of Bi-Based Lead-Free Thin Films.

To achieve large electrostrain and low hysteresis, we further optimized a morphotropic phase boundary (MPB) by modulating its local polar symmetries. The construction of a morphotropic relaxor boundary (MRB) in thin films can be achieved by suitable introduction of Bi(Fe0.95Mn0.03Ti0.02)O3 into (Bi0.5Na0.5)TiO3-SrTiO3 to form a solid solution. The designed thin film achieves surprising piezoelectric properties with an inverse piezoelectric coefficient of 179.7 pm V-1 and negligible hysteresis. The composition of two relaxors with different local polar symmetries (tetragonal nanoregions and rhombohedral nanoregions), namely, an MRB, and the coexistence of multiscale domain structures can greatly weaken the anisotropy of polarization, degrade the energy barrier, attenuate the discontinuity of polarization, and achieve a large electrostrain and low hysteresis. The domain dynamics of the PNRs under the action of an external excitation field are analyzed to clarify the enhancement mechanism. This construction of MRBs is feasible for producing lead-free piezoelectric films with high-voltage electrical properties and low hysteresis, and various experimental design and theoretical references are provided.

Optical ultrasound sensors for photoacoustic imaging: a narrative review.

Optical ultrasound sensors have been increasingly employed in biomedical diagnosis and photoacoustic imaging (PAI) due to high sensitivity and resolution. PAI could visualize the distribution of ultrasound excited by laser pulses in biological tissues. The information of tissues is detected by ultrasound sensors in order to reconstruct structural images. However, traditional ultrasound transducers are made of piezoelectric films that lose sensitivity quadratically with the size reduction. In addition, the influence of electromagnetic interference limits further applications of traditional ultrasound transducers. Therefore, optical ultrasound sensors are developed to overcome these shortcomings. In this review, optical ultrasound sensors are classified into resonant and non-resonant ones in view of physical principles. The principles and basic parameters of sensors are introduced in detail. Moreover, the state of the art of optical ultrasound sensors and applications in PAI are also presented. Furthermore, the merits and drawbacks of sensors based on resonance and non-resonance are discussed in perspectives. We believe this review could provide researchers with a better understanding of the current status of optical ultrasound sensors and biomedical applications.

A comparative study of structural, mechanical & electrical properties of ZnO and AlN thin films for MEMS based piezoelectric sensors

In this work, a comparative study has been carried out to compare the relative performance of ZnO (Zinc Oxide) and AlN (Aluminum Nitride) thin films for their application in piezoelectric sensors. The thin films material properties are being characterized using various material characterization techniques such as SEM, XRD, and Nanoindentation. Further the MIM (Metal-Insulator-Metal) based devices have been fabricated with piezoelectric films sandwiched between Al electrodes. The devices have been evaluated for mechanical and electrical performances. The natural frequency of the devices recorded as 46.8 kHz (ZnO) and 40.8 kHz (AlN). The average nominal capacitance of the MIM structure is measured as ∼98 pF and ∼120 pF where as corresponding dissipation factor obtained as ∼0.03 and ∼0.0005 respectively for ZnO and AlN devices. The repeatability investigation carried out on the sample devices for up to 90 days and the output has been monitored. The result showed that the AlN devices exhibit better output stability compared to ZnO devices.

Thermal stress accommodation in dip cast lead zirconate‐titanate ferroelectric films on flexible substrates

AbstractPiezoelectric thin films were dip coat deposited onto flexible metal substrates to investigate the dependence of dielectric and ferroelectric properties on the coefficient of thermal expansion mismatch and substrate thickness. The bending stiffness was controlled by the thickness of the substrate. Grazing incidence X‐ray diffraction displayed distinct peak splitting for [Pb0.98▪0.01(Zr0.52Ti0.48)Nb0.02O3] on flexible Pt, Ni, Ag, and stiff Ni substrates, where the out‐of‐plane d‐spacing and integrated peak area for c‐domains were highest with the largest film compressive stress. As expected, lead zirconate titanate (PZT) films on stiff Si were under tensile stress and contained more in‐plane domains. The dielectric permittivity was highest in PZT on stiff Si and lowest for PZT on thick Ni, while remanent polarization displayed the opposite trend, commensurate with the residual stress state as well as the resistance to bending in thick substrates as a strain‐relief mechanism. The irreversible Rayleigh coefficient decreased dramatically upon poling for PZT on flexible substrates compared to PZT on stiff substrates; the ratio was 56% higher in PZT on a flexible Ni substrate relative to a stiff Ni substrate at 100 Hz prior to electrical poling. This investigation distinguishes the impact of substrate flexibility from thermal expansion on ferroelectric domain mobility and provides dip‐coating conditions for high‐quality piezoelectric films on any substrate.

Near-field electrospinning-enabled direct-write P(VDF-TrFE) nano/micro-fiber-based piezoelectric film for a high-performance airflow sensor

Airflow sensor is a crucial component in many engineering settings, such as sustainable energy utilization, environmental monitoring, weather forecasting, and aerospace engineering. However, few developed airflow sensors can exhibit decent sensing capability towards ultra-low-speed airflows owing to the performance limitations of sensing elements. In this work, we adopt a near-field electrospinning method to direct-write highly aligned poly(vinylidene-trifluoroethylene) (P(VDF-TrFE)) nano/micro fibers onto a flexible substrate with pre-designed interdigital electrodes to form a piezoelectric sensing film (PSF); the fabricated PSF is then used for airflow sensing application. We theoretically derive the output voltage of a single P(VDF-TrFE) fiber on the PSF under airflow loading, and numerically elucidate the dependency of output voltage on device and experimental parameters. Experimental results show that the lower detection limit of our airflow sensor can be as low as 0.3 m/s with the sensitivity of up to 15 mV/(m/s), which has been hardly accomplished in previous piezoelectric airflow sensors. This study not only presents a high-performance piezoelectric nano/micro-fiber-integrated airflow sensor, but also provides a universal electromechanical analysis method for piezoelectric fiber-based flexible electronics under pressure loading.