Cooling rate controlled microstructure evolution and reduced coercivity in P(VDF–TrFE) devices for memory applications

Singh, Devender; Garg, Ashish

doi:10.1016/j.orgel.2013.10.024

Cited by 21 publications

(13 citation statements)

References 24 publications

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“…The piezoelectricity of P(VDF-TrFE) depended on its crystallinity. In the fabrication of the P(VDF-TrFE) layer, we reduced the temperature of samples by the more common slow cooling process after annealing at 135 °C for 1 h. Fine piezoelectricity and homogeneity cannot be realised if it is cooled down rapidly 53 – 55 .…”

Section: Discussionmentioning

confidence: 99%

Fully Printed Wearable Vital Sensor for Human Pulse Rate Monitoring using Ferroelectric Polymer

Sekine

Sugano

Tashiro

et al. 2018

Sci Rep

104

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The ability to monitor subtle changes in vital and arterial signals using flexible devices attached to the human skin can be valuable for the detection of various health conditions such as cardiovascular disease. Conventional Si device technologies are being utilised in traditional clinical systems; however, its fabrication is not easy owing to the difficulties in adapting to conventional processes. Here, we present the development of a fully printed, wearable, ferroelectric-polymer vital sensor for monitoring the human pulse wave/rate on the skin. This vital sensor is compact, thin, sufficiently flexible, and conforms to the skin while providing high pressure sensitivity, fast response time, superior operational stability, and excellent mechanical fatigue properties. Moreover, the vital sensor is connected to a communication amplifier circuit for monitoring the pulse waves with a wireless sensing system. This sensor system can realise the development of new healthcare devices for wearable sensor applications.

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Section: Discussionmentioning

confidence: 99%

Fully Printed Wearable Vital Sensor for Human Pulse Rate Monitoring using Ferroelectric Polymer

Sekine

Sugano

Tashiro

et al. 2018

Sci Rep

104

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“…To enhance the ferroelectricity of P(VDF-TrFE) by deriving a favorable crystallographic alignment, we removed the devices from the hot plate immediately after thermal annealing. [37] When we compared the molecular packing characteristics of P(VDF-TrFE) films dependent on the cooling rate, split peaks were observed only on the slowly cooled films, indicating the formation of multiple phases (Figure S1, Supporting Information). The fabricated DGOST exhibited characteristics of hysteresis-free p-type transfer in bottom-gate-only operation (Figure 2b), while it showed ferroelectric memory behavior in top-gate operation (Figure 2c).…”

Section: Resultsmentioning

confidence: 99%

A Hippocampus‐Inspired Dual‐Gated Organic Artificial Synapse for Simultaneous Sensing of a Neurotransmitter and Light

Lee

2021

Advanced Materials

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such as light or pressure as inputs. [7,[9][10][11][12][13] Little effort has been made to develop organic artificial synapses that can detect chemicals, especially analytes in a liquid medium.Among the platforms of organic synapses, electrolyte-based organic synaptic transistors have been widely studied because of their high biocompatibility required for future applications of artificial sensory synaptic system from in vitro to in vivo. [14][15][16][17] In order to optimize the synaptic performance and expand the functionality of electrolyte-based synaptic transistors, state-of-the-art organic artificial synapse studies are attempting to implement two or more types of synapse-driving mechanisms in a single device or devise new synaptic device structure. For example, a ferroelectric/electrochemical synapse successfully supplemented conventional electrochemical transistors with longer persistent nonvolatile plasticity and unique threshold switching properties. [18] Also, parallel programming of organic synapses has been demonstrated by connecting a gate terminal of an organic redox transistor to a diffusive memristor. [19] Therefore, in order to expand functionality of various organic synapses, it is necessary to explore organic synaptic transistors with various operation mechanisms and device structures and, as a result, combine their advantageous characteristics.In a biological synapse, which is a principal emulation target of neuromorphic devices, excitation or inhibition occurs via the release or reception of neurotransmitters. Therefore, it is of great benefit to develop artificial sensory synaptic system which recognizes neurotransmitter signals and modulates postsynaptic currents including potentiation/depression, paired-pulse facilitation, and Hebbian learning. [20][21][22] Among various neurotransmitters, dopamine plays an important role in learning and memory consolidating functions of hippocampal memory, affecting plasticity, synaptic transmission, and network activity in the hippocampal circuitry. [23][24][25] Recently, a biohybrid synapse with dopaminergic PC-12 cells coupled to an organic neuromorphic device has been reported to enable dopamine signaling in artificial synapses. [26] This approach was based on continuous exposure of both sensing and signal processing parts to the wet environment, cell incubation, and immobilizing process. Thus, it will also be interesting to develop a dopaminergic signaling Organic neuromorphic devices and sensors that mimic the functions of chemical synapses and sensory perception in humans have received much attention for next-generation computing and integrated logic circuits. Despite recent advances, organic artificial synapses capable of detecting both neurotransmitters in liquid environments and light are not reported. Herein, inspired by hippocampal synapses, a dual-gate organic synaptic transistor platform with a photoconductive polymer semiconductor, a ferroelectric insulator of P(VDF-TrFE), and an extended-gate electrode functionalized with boronic acid is d...

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“…Based on their piezoelectric, pyroelectric, and ferroelectric properties, both polymers can be designed as sensors, actuators, and memories . P(VDF‐TrFE) films are usually deposited from solution and their ferroelectric β phase is further enhanced via post annealing process . However, depending on its different chain conformations of trans (T) and gauge (G), semi‐crystalline PVDF possesses much complicated structures with at least four crystalline polymorphs, including α (TGTḠ), β (TTTT), γ (T 3 GT 3 Ḡ), and δ (polarized α) phases .…”

Section: Introductionmentioning

confidence: 99%

Electroactive PVDF thin films fabricated via cooperative stretching process

Wang

Chen

Xia

et al. 2018

J of Applied Polymer Sci

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Ferroelectric polymers have obtained much attention in low cost and flexible electronics. As one representative ferroelectric polymer, poly(vinylidene fluoride) (PVDF) has been comprehensively studied. Due to its complicated phase composition, fabrication of electroactive phases has been an open question especially for PVDF thin films deposited on solid substrates. Here cooperative stretching process is introduced for the fabrication of electroactive PVDF thin films. PVDF thin films are coated on stretchable poly(vinyl alcohol) substrates and mechanically stretched under optimized stretching parameters. Structural, spectral, and electrical measurements indicate that cooperative stretching process can effectively convert the nonpolar a phase to the electroactive b and g phases companied by an enhancement of film crystallinity. Stretched PVDF films present a reverse piezoelectric coefficient of 237 pm/V, comparable with the results from films fabricated by the other techniques. V C 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46324.

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Cooling rate controlled microstructure evolution and reduced coercivity in P(VDF–TrFE) devices for memory applications

Cited by 21 publications

References 24 publications

Fully Printed Wearable Vital Sensor for Human Pulse Rate Monitoring using Ferroelectric Polymer

Fully Printed Wearable Vital Sensor for Human Pulse Rate Monitoring using Ferroelectric Polymer

A Hippocampus‐Inspired Dual‐Gated Organic Artificial Synapse for Simultaneous Sensing of a Neurotransmitter and Light

Electroactive PVDF thin films fabricated via cooperative stretching process

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