Space charge and dipoles in polyvinylidenefluoride

Eisenmenger, Wolfgang; Schmidt, Helmut; Dehlen, B.

doi:10.1590/s0103-97331999000200011

Cited by 50 publications

(38 citation statements)

References 10 publications

(1 reference statement)

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“…Hence, it appears plausible that the measured TSC peak at 25 ○ C in Fig. 4.17(a) and (b) is due to space charges as described by Rollik et al This would also fit to the results found by Eisenmenger et al [25][26][27][28] , who discussed the importance of charge trapping for the stabilization of the ferroelectric polarization in PVDF. Thus, the peaks may prove charge injection into insulator as well as persistent trapping of the charges up to the temperature of 25 ○ C for both polarization directions.…”

Section: Effect Of Stable Ferroelectric Polarization On Thermally Stisupporting

confidence: 81%

“…28 However, the stability of the polarization and therefore the lack of hysteresis in the unipolar sweeps taken up to 6 hours after switching the ferroelectric polarization (Fig. 4.4(d)) does not support such an argument.…”

Section: Stability Of Polarization In Organic Ferroelectric Metal-insmentioning

confidence: 89%

“…Before the TSC measurement the sample was subjected to a pre-poling where bias voltages of ±30 V was alternated 5 times to ensure that all ferroelectric domains are fully poled. 25,28 Each voltage step of the pre-poling was applied for 1 min. Directly after the pre-poling the TSC measurement started with the poling at either +30 V or −30 V for 4 min at a temperature of 20 ○ C followed by the cooling of the sample.…”

Section: Experimental and Discussionmentioning

confidence: 99%

“…At first glance, this argument seems reasonable because it is supported by the finding that PVDF and its copolymers require compensation charges to maintain a remanent ferroelectric polarization. 27,28 It is not possible to directly retrieve information about the orientation of dipolemoment and the orientational stability of a ferroelectric insulator from capacitance spectra. Therefore at this point the argumentation by Naber et al could theoretically serve as a possible explanation for the measured instability.…”

Section: Influence Of Remanent Polarization Of the Insulator On Maxwementioning

confidence: 99%

“…The effect of stable polarization, however, is not only a pure intrinsic effect of P(VDF-TrFE) films but may be largely influenced by the presence of charges as discussed in reviews articles by Eberle et al 26 and Eisenmenger et al 28 Measurements presented in these articles suggest the depolarization of P(VDF-TrFE) films within minutes, when charge injection was prevented…”

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confidence: 99%

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Stability of polarization in organic ferroelectric metal-insulator-semiconductor structures

Kalbitz

Frübing

Gerhard

et al. 2011

Applied Physics Letters

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Dielectric measurements have been carried out on all-organic metal-insulator-semiconductor structures with the ferroelectric polymer poly(vinylidenefluoride-trifluoroethylene) as the gate insulator. It is shown that the polarization states remain stable after poling with accumulation and depletion voltage. However, negative charge trapped at the semiconductor-insulator interface during the depletion cycle masks the negative shift in flatband voltage expected during the sweep to accumulation voltages.

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Section: Effect Of Stable Ferroelectric Polarization On Thermally Stisupporting

confidence: 81%

Section: Stability Of Polarization In Organic Ferroelectric Metal-insmentioning

confidence: 89%

Section: Experimental and Discussionmentioning

confidence: 99%

Section: Influence Of Remanent Polarization Of the Insulator On Maxwementioning

confidence: 99%

mentioning

confidence: 99%

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Stability of polarization in organic ferroelectric metal-insulator-semiconductor structures

Kalbitz

Frübing

Gerhard

et al. 2011

Applied Physics Letters

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Utilizing Highly Crystalline Pyroelectric Material as Functional Gate Dielectric in Organic Thin‐Film Transistors

et al. 2009

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Since the first description of their use as potential elements for electronic devices, [1] in 1987, organic thin-film transistors (OTFTs) have been intensively studied, due to their potentially lower cost, higher performance, and higher compatibility with flexible electronic applications, as compared to conventional silicon technology. [2][3][4][5] Recently, new functions of OTFTs and their integrated circuits have been being considered, in an attempt to take advantage of organic electronic devices in different applications, such as memory, [6,7] radio-frequency identification (RFID), [8] and sensors. [9][10][11][12] For functional organic devices, organic smart materials with ferroelectric, piezoelectric, and pyroelectric properties can be directly integrated into the OTFT device structure. Good candidates are poly(vinylidene fluoride) (PVDF) and its copolymer with trifluoroethylene, P(VDF-TrFE). The piezo-and pyroelectricity of PVDF and P(VDF-TrFE) were studied in depth, [13][14][15][16][17][18][19][20][21][22] and have been successfully applied in many research fields, [23] but the applications of these properties in OTFTs are limited to external sensing modules. [9,11] On the other hand, there have been both theoretical and experimental reports of memory applications based on the ferroelectricity of P(VDF-TrFE) in OTFTs. [6,7,[24][25][26] High current on-off ratio and fast switching dipoles, which imply a small remnant polarization, are the key aspects in this case. In applications making use of the pyroelectric and piezoelectric properties of P(VDF-TrFE), however, the switching of small remnant polarization should be avoided, and a stable large polarization is required instead. Thus, physical models based on the assumption of small and easy-to-switch remnant polarizations [24][25][26] are not appropriate in interpreting the experimental observation in this work, showing a very large remnant polarization, and need to be modified in order to accurately interpret the experimental information.In this report, we present for the first time the direct use of a highly crystalline P(VDF-TrFE) material with a very large remnant polarization as a pyroelectric gate-insulator layer in an OTFT structure for temperature-sensing applications. This has the advantage of a simpler fabrication process compared to external sensing modules. A poling strategy based on step-wise poling process [20] was required to enhance the effects of the pyroelectricity on the transistor performance (see Experimental). The output characteristics of the OTFTs were changed so as to exhibit a linear current-voltage relationship, thus providing evidence of their large polarization. We introduced a modified transistor equation to fully explain this phenomenon and related problems, such as the effect of the geometry on poling. The thermal behavior of the functional OTFT was also investigated, and the results showed a linear response below the phase transition temperature of P(VDF-TrFE). The temperature response of the device was primarily attributed t...

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Recent Advances in Ferroelectret Fabrication, Performance Optimization, and Applications

Wang,

Zhang,

Qiu

et al. 2024

Advanced Materials

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The growing demand for wearable devices has sparked a significant interest in ferroelectret films. They possess flexibility and exceptional piezoelectric properties due to strong macroscopic‐dipoles formed by charges trapped at the interface of their internal cavities. This review of ferroelectrets focuses on the latest progress in fabrication techniques for high temperature resistant ferroelectrets with regular and engineered cavities, strategies for optimizing their piezoelectric performance, and novel applications. The charging mechanisms of bipolar and unipolar ferroelectrets with closed and open‐cavity structures are explained first. Next, the preparation and piezoelectric behavior of ferroelectret films with closed, open and regular cavity structures using various materials are discussed. Three widely used models for predicting the piezoelectric coefficients (d33) are outlined. Methods for enhancing the piezoelectric performance such as optimized cavity design, utilization of fabric electrodes, injection of additional ions, application of DC bias voltage and synergy of foam structure and ferroelectric effect are illustrated. A variety of applications of ferroelectret films in acoustic devices, wearable monitors, pressure sensors and energy harvesters are presented. Finally, the future development trends of ferroelectrets towards fabrication and performance optimization are summarized along with its potential for integration with intelligent systems and large‐scale preparation.This article is protected by copyright. All rights reserved

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Space charge and dipoles in polyvinylidenefluoride

Cited by 50 publications

References 10 publications

Stability of polarization in organic ferroelectric metal-insulator-semiconductor structures

Stability of polarization in organic ferroelectric metal-insulator-semiconductor structures

Utilizing Highly Crystalline Pyroelectric Material as Functional Gate Dielectric in Organic Thin‐Film Transistors

Recent Advances in Ferroelectret Fabrication, Performance Optimization, and Applications

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