VDF TrFE Research Articles

Multiscale insights into electric field orientation effects on piezoelectric strain and crystallography in P(VDF–TrFE) and P(VDF–TrFE–CTFE) fibers

This research primarily focuses on the effect of changing electric field directions on the crystal structure of piezoelectric fibers, notably, P(VDF–TrFE) and P(VDF–TrFE–CTFE). The study also explores the deformation mechanisms of fibers at micro- and nanoscales. A significant aspect of the research involves the application of parallel and perpendicular electric fields and observation of their impact on fiber properties. In situ wide-angle X-ray diffraction (WAXD) studies are crucial for determining the nanoscale properties when the electric field orientations change. The results show that the direction of the electric field significantly affects the sign (positive or negative) of the dipole vector within the β-crystal lattice structure of the fibers. This can be attributed to the rotation of dipole vectors in response to the electric field–fiber alignment angle. Furthermore, the research identifies the crystal plane (201,111)β as exhibiting the highest magnitude of piezoelectric response strain in the β phase. The study also employs scanning electron microscopy and digital image correlation (DIC) to reveal the material's morphology and to assess fiber strain distribution at the micrometer scale under different voltages. DIC results particularly highlight that stress concentration leads to the deformation of fibers into voids, which are spaces between fibers created by electrospinning. This work comprehensively elucidates how deformation works in piezoelectric polymers by connecting large-scale changes observed in fibers through DIC and small-scale changes observed in WAXD studies presenting the piezoelectric strain responses at the crystal plane.

Addressing Triboelectric Nanogenerator Impedance for Efficient CO2 Utilization

AbstractReducing the impedance of a triboelectric nanogenerator (TENG) without power loss is crucial for enhancing its energy conversion efficiency and overall performance. In this paper, a novel signal management structure, based on a newly designed sliding‐mode TENG, aimed at effectively reducing impedance by converting narrow, instantaneous signals into broader ones is presented. This transformation is accomplished by adding a grounded electrode connected to a high‐inductive inductor and fine‐tuning the parasitic capacitance of the dielectric material. Utilizing a highly resistive material like P(VDF–TrFE), a significant improvement in the TENG's performance is achieved, resulting in an increase of output power to 0.352 mW and a decrease in impedance from 3.2 to 0.3 MΩ. This results in a threefold increase in charging speed, which can be attributed to the reduced charge loss and improved matching at lower impedance. Based on these promising findings, the enhanced TENG is successfully connected to power a system for electrochemical CO2 reduction for CO production. This system effectively reduces the required electrochemical reduction potential by ≈15% under real environments.

A simple, efficient, and environmentally friendly strategy for preparing P(VDF–TrFE) with double bonds

A simple, efficient, and environmentally friendly strategy for preparing P(VDF–TrFE) with double bonds

Reconfigurable Physical Reservoir Enabled by Polarization of Ferroelectric Polymer P(VDF–TrFE) and Interface Charge‐Trapping/Detrapping in Dual‐Gate IGZO Transistor

AbstractNeuromorphic computers promise to enhance computing efficiency by eliminating conventional von Neumann architecture bottlenecks. Bio‐inspired artificial neural networks, such as feedforward neural networks and reservoir computing (RC), face challenges due to the unique memristor requirements. In this study, a dual‐gate ferroelectric polymer P(VDF–TrFE)‐coupled thin film transistor (DG–TFT) with an IGZO channel is presented. It yields complementary short‐ and long‐term memory functionalities are derived from the charge‐trapping/detrapping process at the IGZO‐SiO2 dielectric interface and ferroelectric polarization. These memory functionalities can be switched using different gated modes to meet the requirements of the reservoir and readout layers in RC. The bottom‐gated mode (BG‐mode) exhibits short‐term memory effects and nonlinear dynamics, whereas the top‐gated mode (TG‐mode) displays improved long‐term memory characteristics. To evaluate the long‐term memory properties, Python is used for pattern recognition. For the nonlinear dynamics and short‐term memory response of the BG‐mode, the DG–TFT is employed as a reservoir layer to handle various temporal tasks. Notably, the polarization level of the ferroelectric layer is coupled to improve the richness of the reservoir states, providing a reconfigurable RC system with an expanded capacity to effectively process and accommodate diverse signals. This holds potential for next‐generation hybrid intelligent applications.

Structure and Dielectric Properties of Poly(vinylidenefluoride-co-trifluoroethylene) Copolymer Thin Films Using Atmospheric Pressure Plasma Deposition for Piezoelectric Nanogenerator.

This study investigates the structural phase and dielectric properties of poly(vinylidenefluoride-co-trifluoroethylene) (P[VDF-TrFE]) thin films grown via atmospheric pressure (AP) plasma deposition using a mixed polymer solution comprising P[VDF-TrFE] polymer nano powder and dimethylformamide (DMF) liquid solvent. The length of the glass guide tube of the AP plasma deposition system is an important parameter in producing intense cloud-like plasma from the vaporization of DMF liquid solvent containing polymer nano powder. This intense cloud-like plasma for polymer deposition is observed in a glass guide tube of length 80 mm greater than the conventional case, thus uniformly depositing the P[VDF-TrFE] thin film with a thickness of 3 μm. The P[VDF-TrFE] thin films with excellent β-phase structural properties were coated under the optimum conditions at room temperature for 1 h. However, the P[VDF-TrFE] thin film had a very high DMF solvent component. The post-heating treatment was then performed on a hotplate in air for 3 h at post-heating temperatures of 140 °C, 160 °C, and 180 °C to remove DMF solvent and obtain pure piezoelectric P[VDF-TrFE] thin films. The optimal conditions for removing the DMF solvent while maintaining the β phases were also examined. The post-heated P[VDF-TrFE] thin films at 160 °C had a smooth surface with nanoparticles and crystalline peaks of β phases, as confirmed by the Fourier transform infrared spectroscopy and XRD analysis. The dielectric constant of the post-heated P[VDF-TrFE] thin film was measured to be 30 using an impedance analyzer at 10 kHz and is expected to be applied to electronic devices such as low-frequency piezoelectric nanogenerators.

Proton Irradiation Effects on the Pyroelectric Properties of P‐Type Bismuth Antimonide/Poly(vinylidene fluoride–trifluoroethylene) Composite Films

AbstractOrganic pyroelectric materials are widely applied as temperature sensors in wearable electronic devices due to their good biocompatibility and stability. Real‐time monitoring of the physiological state of the human body requires pyroelectric materials with a fast response time and large output voltage. In this study, the pyroelectric characteristics of poly(vinylidene fluoride–trifluoroethylene) (P(VDF–TrFE)) films are improved with the use of commercial inorganic P‐type bismuth antimonide (P‐Bi2Te3) fillers. Composite films with 0.2 wt% P‐Bi2Te3 increase the pyroelectric response time and voltage by improving the thermal diffusivity and enhancing the β‐phase content, respectively. Proton irradiation results in further improvement of the pyroelectric response time from 22 to 0.5 s. The proton irradiation‐induced ionization energy loss improves the conductivity of the composite films, thereby enhancing the pyroelectric response time. These results show that P‐Bi2Te3 doping is beneficial for improving the pyroelectric properties of P(VDF–TrFE) and that proton irradiation is an effective method for further improving the response time of inorganic–organic composite films.

The effect of permanent electric dipoles on the stability and photoelectric properties of MAPbI3 films

P(VDF–TrFE) dipoles reduce ion migration and improve film stability via the interaction between ferroelectric dipoles and the ions in MAPbI3, and enhance the photoelectric performance of MAPbI3 by reducing the trap-assisted capture radius.

Tailored magnetoelectric coupling in magnetically oriented polymer-based iron fiber composite

Artificial multiferroics magnetoelectric (ME) polymer composite films exhibiting collective ferroelectric and magnetic orderings are gaining attractive for the use of flexible ME devices. Herein an anisotropic polymer-based ME composites films is developed, composed of magnetically oriented polycrystalline iron fiber (Fef) and poly(vinylidene fluoride-co-trifluoroethylene) P(VDF–TrFE). The structure, ferroelectric, piezoelectric, magnetic, and ME properties was systematically investigated. Both Fef fillers content and magnetic field direction determined the ME voltage coefficient, magnetical polarization and dielectric response in anisotropic P(VDF-TrFE)–Fef composites. Specifically, the composite with 16% filler loading delivers a peak ME value of 44.5 mV·cm−1·Oe−1 with magnetic field exerted along the fiber axial alignment direction. Such extracted results may encourage a way to optimize flexible composite in anisotropic contactless sensing and detecting applications.

The Influence Mechanism of Temperature and Storage Period on Polarization Properties of Poly (Vinylidene Fluoride-Trifluoroethylene) Ultrathin Films.

The effect of testing temperature and storage period on the polarization fatigue properties of poly (vinylidene fluoride-trifluoroethylene) (P(VDF–TrFE)) ultrathin film devices were investigated. The experimental results show that, even after stored in air for 150 days, the relative remanent polarization () of P(VDF–TrFE) of ultrathin films can keep at a relatively high level of 0.80 at 25 °C and 0.70 at 60 °C. To account for this result, a hydrogen fluoride (HF) formation inhibition mechanism was proposed, which correlated the testing temperature and the storage period with the microstructure of P(VDF–TrFE) molecular chain. Moreover, a theoretical model was constructed to describe the polarization fatigue evolution of P(VDF–TrFE) samples.

Application of P(VDF-TrFE) Glass Coating for Robust Harmonic Nanoparticles Characterization.

Polyvinylidene fluoride and its copolymers are a well-known family of low-cost ferroelectric materials widely used for the fabrication of devices for a wide range of applications. A biocompatibility, high optical quality, chemical and mechanical durability of poly(vinylidene fluoride–trifluoroethylene), (P(VDF–TrFE)), makes it particularly attractive for designing of effective coating layers for different diagnostic techniques. In the present work, the nonlinear optical characterization of P(VDF-TrFE)-coating films deposited onto a glass substrate was done. Advantages of the coating application for cells/substrates in the field of multiphoton imaging the efficiency of such coating layer for long-duration characterization of so-called harmonic nanoparticles (HNPs) were shown. The influence of glass surface protection by P(VDF-TrFE) film from an effect of HNPs sticking to the walls of the flow-cell was analyzed for effective studying of the optical harmonics generation efficiency of HNPs making the analysis more robust.

Preparation, characterization and microhardness measurements of hybrid nanocomposites based on PMMA + P(VDF–TrFE) and graphene oxide

The polymer nanocomposites samples of the poly (methyl methacrylate) (PMMA)—poly (vinylidene fluoride–trifluoroethylene) P(VDF–TrFE) with graphene oxide (GO) were prepared by solution casting method. The impact of GO on electroactive polar β-phase of PMMA + P(VDF–TrFE) was investigated through the Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy. The mechanical properties of nanocomposites samples have been investigated by measurement of microhardness. The value of microhardness and indentation depends on applied load on samples. The experimental result suggests that mechanical properties of samples decrease in presence of GO due to decrease in uniaxial orientation or agglomeration of GO. Surface characteristics such as surface free energy, interfacial free energy and hydrophobicity were determined by measuring the contact angle.

Mechano-electric coupling in P(VDF–TrFE)/spin crossover composites

Spin crossover particles dispersed in a piezo/ferroelectric poly(vinylidene fluoride-co-trifluoro-ethylene), P(VDF–TrFE), matrix give rise to inspiring mechano-electric phenomena, with possible applications for energy harvesting and sensing.

Piezoelectric polymer nanofibers for pressure sensors and their applications in human activity monitoring.

Miniaturized, wearable and self-powered sensors are crucial for applications in artificial intelligence, robotics, healthcare, and communication devices. In particular, piezoelectric polymer-based sensing systems have the advantages of light weight, large piezoelectricity and mechanical flexibility, offering great opportunities in flexible and stretchable electronic devices. Herein, free-standing large-size nanofiber (NF) membranes have been fabricated by an electrospinning technique. Our results show that the as-synthesized P(VDF–TrFE) NFs are pure β-phase and exhibit excellent mechanical and thermal properties. Besides having high sensitivity and operational stability, the fibrous sensor can generate remarkable electrical signals from applied pressure, with an output voltage of 18.1 V, output current of 0.177 μA, and power density of 22.9 μW cm−2. Moreover, such sensors also produce significant electrical performance of up to a few volts under human mechanical stress, thereby allowing for the monitoring of biomechanical movement of the human foot, elbow, and finger. Our study sheds light onto the use of piezoelectric polymers for flexible self-powered sensing electronics and wearable devices.

Tunable dielectric polarization and breakdown behavior for high energy storage capability in P(VDF-TrFE-CFE)/PVDF polymer blended composite films.

Polymer dielectrics with high dielectric performances and superior discharge energy capability are highly desirable for advanced electrostatic capacitor applications. However, the paradoxical relationship between dielectric polarization and electric breakdown behavior generally hinder their further enhancement in energy storage performances. Herein, polymer blended composite films with high energy storage capability were successfully fabricated by blending together poly(vinylidene fluoride) (PVDF) polymer and poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) terpolymer. The P(VDF-TrFE-CFE) terpolymer has a high dielectric constant to provide a large electric displacement under an applied electric field far below its breakdown field, which is anticipated to modulate the dielectric polarization behavior of PVDF polymer when blended in different proportions. Consequently, the polymer blended composite film consisting of 20 wt% (P(VDF-TrFE-CFE)) terpolymer exhibits a high discharge energy density of 13.63 J cm-3 at an enhanced breakdown strength of 480 MV m-1. This obtained high discharge energy density is 84% higher than the pure PVDF film and 582% higher than a commercialized biaxially oriented polypropylene (BOPP). Large interfacial polarization and strong interaction of polymer chains between the PVDF polymer and P(VDF-TrFE-CFE) terpolymer may contribute to the tunable dielectric constant and electric breakdown strength, thus promoting the energy storage capability. This work establishes a facile, but effective approach to achieve the high energy storage capability of PVDF polymer-based flexible composite films for capacitive energy storage applications.

Synergistic Effects of Maxwell Stress and Electrostriction in Electromechanical Properties of Poly(vinylidene fluoride)-Based Ferroelectric Polymers

Poly(vinylidene fluoride) (PVDF)-based relaxor ferroelectric polymers, synthesized from the physical or chemical modification of β-PVDF and P(VDF–TrFE) (TrFE refers trifluoroethylene), show high th...

P(VDF–TrFE) based spiral thermo-magneto-electric generators for harvesting low grade thermal energy

Low-grade thermal energy harvesting remains a challenge because of the low Carnot efficiency. Among various thermal energy harvesting mechanisms available for capturing low-grade heat (hot-side temperature less than 100°C), thermomagnetic effect has been found to be the most promising. Developing a high power density thermo-magneto-electric generator (TMEG) requires developments at both materials as well engineering levels. In this study, we propose a novel P(VDF–TrFE) based spiral-shaped cantilever beam for TMEG. Numerical simulations were performed using COMSOL Multiphysics and it was found that spiral beam experiences higher stresses, and consequently exhibits higher voltage output, as compared to rectangular cantilever beam for the same magnitude of tip deflection. Experiments revealed that the spiral structure of dimension 2.5 mm x 2.5 mm generates output voltage of about 4.0 mV, when oscillation displacement is 0.5 mm and oscillation frequency is 1 Hz. The output voltage increases with increase in tip deflection as well as oscillation frequency and a peak voltage of 25 mV is obtained at oscillation frequency of 10 Hz.

Preparation and Dielectric Characterization of P(VDF–TrFE) Copolymer-Based Composites Containing Metal–Formate Frameworks

We report the synthesis and dielectric characterization of novel polyvinylidene fluoride-trifluoroethylene P(VDF-TrFE) composite films containing [(CH3)2NH2][Mg(HCOO)3] (DMAMg) and [NH4][Zn(HCOO)3] (AmZn) dense metal-organic frameworks (MOFs). The optical camera and Raman microscopies are used to map the distribution of the MOF fillers in the prepared films. The dielectric spectroscopy experiments of the DMAMg/P(VDF-TrFE) composite performed in a broad temperature range demonstrate rich dielectric behavior originating from the dipolar dynamics of the (CH3)2NH2+ molecular cations and glassy behavior of the copolymer matrix. An anomalous behavior of the complex dielectric permittivity is also observed because of the structural phase transition of DMAMg fillers. The dielectric properties of the AmZn/P(VDF-TrFE) composite film are mainly determined by the dipolar glass relaxation of the P(VDF-TrFE) polymer. The frequency-dependent dielectric spectra of both composites allow us to characterize the observed dipolar relaxation processes. The (CH3)2NH2+ cation dynamics follows the Arrhenius law, whereas the glassy behavior of P(VDF-TrFE) is described by the Vogel-Fulcher equation. For both composites, we observe a significant increase of the dielectric permittivity compared with the P(VDF-TrFE) film without MOF fillers.

All-printed multilayer materials with improved magnetoelectric response

For the first time is reported the development of a screen printed flexible magnetoelectric material based on P(VDF–TrFE), PVDF and CoFe2O4. The ME voltage coefficient of 164 mV cm−1Oe−1at a longitudinal resonance frequency of 16.2 kHz, the highest reported in the literature, certifies the use of the printed material on printed electronics, sensors, actuators, and energy harvesters.

Piezoelectric energy harvesting and charging performance of Pb(Zn1/3Nb2/3)O3–Pb(Zr0.5Ti0.5)O3 nanoparticle-embedded P(VDF-TrFE) nanofiber composite sheets

Piezoelectric composite structures have been studied to optimize energy harvesting and charging performance. Here, a specific piezoelectric composition of 0.4Pb(Zn1/3Nb2/3)O3–0.6Pb(Zr0.5Ti0.5)O3 (PZN–PZT) has been selected for better energy harvesting performance. Different contents of PZN-PZT nanoparticles of ∼54 nm were embedded into a matrix of poly(vinylidene fluoride–trifluoroethylene) [P(VDF–TrFE)] by a single electrospinning process. The single-phase perovskite nanoparticles were initially prepared by combustion synthesis with the assistance of polyacrylic acid (PAA) as a fuel. The enhanced energy harvesting performance of flexible composite nanogenerators was ascertained by exhibiting ∼3.4 V output voltage and ∼240 nA output current for the 20 vol% nanoparticles-incorporated single sheet. The charging capability was found to be enhanced by designing the stacked nanofiber composite sheets in series, suggesting that the rate of charging and the saturation voltage are dependent on the number of composite sheets in series. For instance, the double stacked sheets exhibited a ∼5.7 V charging capability within ∼150 s.

Direct piezoelectric response in vinylidene fluoride–trifluoroethylene copolymer films

The effective transverse piezoelectric coefficient e31,f in vinylidene fluoride–trifluoroethylene copolymer [P(VDF–TrFE), 75/25 mol %] films was investigated. 2-µm-thick P(VDF–TrFE) films were deposited by spin coating on a Pt/Si substrate at a valid annealing temperature from 100 to 160 °C. The phase development and surface morphology suggest that the films were melted by annealing at 150 °C and above, and that gauche defects increase with the annealing temperature. Although all the films have similar dielectric constants between 8 and 10, the remanent polarization Pr and coefficient e31,f show maximum values of 9.1 µC/cm2 and 140 mC/m2, respectively, at 140 °C. These results indicate that the ferroelectric and piezoelectric properties of P(VDF–TrFE) films are enhanced by annealing just below the melting point.