• 제목/요약/키워드: P(VDF)

검색결과 91건 처리시간 0.031초

강유전 고분자 박막의 상전이 특성 (Phase Transition Properties of Ferroelectric Polymer Films)

  • 박철우;정치섭
    • 한국전기전자재료학회논문지
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    • 제27권2호
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    • pp.97-103
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    • 2014
  • Phase transition properties of the copolymer films of polyvinylidene fluoride (PVDF) and trifluoroethylene(TrFE), P(VDF-TrFE), were studied with X-ray diffraction (XRD) and polarization modulated ellipsometry (PME). XRD studies on both Langmuir-Blodgett (LB) films and spin coated films exhibit conversions from ferroelectric phase to paraelectric phase at $108{\pm}2^{\circ}C$ on heating and paraelectric phase to ferroelectric phase at $78{\pm}2^{\circ}C$ on cooling. The presence of the ferroelectric-paraelectric phase transition is also confirmed by the PME technique for the first time in this study. PME was proved to be a very sensitive tool in the measurement of the structural changes at the nano-thickness films.

Low voltage operated top gated polymer thin film transistors with a high capacitance polymer dielectric

  • Jung, Soon-Won;You, In-Kyu;Noh, Yong-Young
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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    • pp.907-909
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    • 2009
  • Low voltage operated top gated polymer transistors were fabricated with a high permittivity polymer, P(VDF-TrFE) and F8T2 as a gate dielectric and semiconducting layer, respectively. The operating voltage of transistors was effectively reduced under -10 V and typical threshold voltages were as low as -1 ~ -4 V with the reasonable charge carrier mobility of $10^{-3}cm^2$/Vs for the amorphous polymer. The large hysteresis in transfer curve was improved effectively by annealing at low temperature.

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강유전 고분자 박막의 저차원 전기광학 특성 (Low Dimensional Electro-optic Properties of Ferroelectric Polymer Films)

  • 박철우;정치섭
    • 한국전기전자재료학회논문지
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    • 제27권3호
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    • pp.184-188
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    • 2014
  • The electro-optic properties in Langmuir Blodgett films of poly (vinylidene fluoride trifluoroethylene) are investigated in the crossover region between two and three dimensions. The absence of finite size effect is observed in the films thinner than 20 nm, which confirms that these films are two dimensional ferroelectrics. The copolymer LB film of P(VDF-TrFE) exhibits the largest electro-optic response(26 pm/V) at 10 layer thickness. The cross-over behavior of electro-optic effect around the 10 layer thickness was discussed with the formation of nanomesa after thermal annealing.

Transparent and Flexible All-Organic Multi-Functional Sensing Devices Based on Field-effect Transistor Structure

  • Trung, Tran Quang;Tien, Nguyen Thanh;Seol, Young-Gug;Lee, Nae-Eung
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제40회 동계학술대회 초록집
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    • pp.491-491
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    • 2011
  • Transparent and flexible electronic devices that are light-weight, unbreakable, low power consumption, optically transparent, and mechanical flexible possibly have great potential in new applications of digital gadgets. Potential applications include transparent displays, heads-up display, sensor, and artificial skin. Recent reports on transparent and flexible field-effect transistors (tf-FETs) have focused on improving mechanical properties, optical transmittance, and performances. Most of tf-FET devices were fabricated with transparent oxide semiconductors which mechanical flexibility is limited. And, there have been no reports of transparent and flexible all-organic tf-FETs fabricated with organic semiconductor channel, gate dielectric, gate electrode, source/drain electrode, and encapsulation for sensor applications. We present the first demonstration of transparent, flexible all-organic sensor based on multifunctional organic FETs with organic semiconductor channel, gate dielectric, and electrodes having a capability of sensing infrared (IR) radiation and mechanical strain. The key component of our device design is to integrate the poly(vinylidene fluoride-triflouroethylene) (P(VDF-TrFE) co-polymer directly into transparent and flexible OFETs as a multi-functional dielectric layer, which has both piezoelectric and pyroelectric properties. The P(VDF-TrFE) co-polumer gate dielectric has a high sensitivity to the wavelength regime over 800 nm. In particular, wavelength variations of P(VDF-TrFE) molecules coincide with wavelength range of IR radiation from human body (7000 nm ~14000 nm) so that the devices are highly sensitive with IR radiation of human body. Devices were examined by measuring IR light response at different powers. After that, we continued to measure IR response under various bending radius. AC (alternating current) gate biasing method was used to separate the response of direct pyroelectric gate dielectric and other electrical parameters such as mobility, capacitance, and contact resistance. Experiment results demonstrate that the tf-OTFT with high sensitivity to IR radiation can be applied for IR sensors.

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압전고분자 초음파 트랜스듀서와 생의학적 응용 (Piezoelectric Polymer Ultrasound Transducers and Its Biomedical Applications)

  • 하강렬;조영강
    • 비파괴검사학회지
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    • 제32권5호
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    • pp.585-596
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    • 2012
  • PVDF와 P(VDF-TrFE)로 대별되는 압전고분자는 종래의 대표적인 압전재료인 PZT에 비해 전기음향변환효율이 떨어지며 내부손실이 큰 단점은 있으나, 음향임피던스가 물 또는 생체와 비슷하고 수신효율이 우수하며 광대역 특성을 나타내는 등의 장점을 가진 재료이다. 또한 다른 압전재료에 비해 얇은 막으로의 제작이 쉽고, 그 막은 유연하므로 복잡한 곡면을 갖는 고주파 초음파 트랜스듀서 재료로 유용하다. 그러한 특성은 생의학적 응용에 적합한바, 다양한 형태의 초음파 트랜스듀서가 연구 개발되어져 왔다. 본 논문에서는 먼저, 압전고분자막을 이용하여 초음파 트랜스듀서를 설계 제작하는데 있어서 고려해야할 몇 가지 주요사항을 기술하고, KLM 모델을 사용한 해석을 통하여 그 고려사항들이 트랜스듀서의 동작에 미치는 영향을 파악하였다. 다음으로, 의학적 또는 생물학적 응용을 목적으로 초음파 영상을 얻고 있는 몇몇 주요 응용분야에서 사용되는 압전고분자 트랜스듀서의 구조와 그것을 이용하여 얻은 영상의 특징에 대하여 간략히 해설하였다.

상전이법을 이용한 P(VDF-co-HFP) 분리막 구조제어 (Controlling the Morphology of Polyvinylidene-co-hexafluoropropylene (PVDF-co-HFP) Membranes Via Phase Inversion Method)

  • 송예진;김종후;김예솜;김상득;조영훈;박호식;남승은;박유인;손은호;김정
    • 멤브레인
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    • 제28권3호
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    • pp.187-195
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    • 2018
  • 본 연구에서는 상전이법을 이용하여 P(VDF-co-HFP) 분리막의 구조를 조절하였다. Macrovoid 없는 구조를 얻기 위하여 다양한 조건에서 비용매유도상전이(NIPS) 공법으로 분리막을 제막하였으나 고분자의 낮은 결정화 속도로 인해 macrovoid가 생성된다는 것을 관측하였다. 이를 극복하기 위해 증발유도상전이법(EIPS)과 증기유도상전이법(VIPS)을 도입하였으며 NIPS공법과 함께 제막되었을 때 이상적인 구조를 얻을 수 있다는 것을 확인하였다.

Fabrication and Characteristics of Pyroelectric Infrared Sensor Using $PbTiO_3$/P(VDF/TrFE) Nanocomposites Thin Film (ICCAS 2004)

  • Kwon, Sung-Yeol;Bae, Jong-Il;Jo, Bong-Kwan;Kim, Do;Ahn, Doo-Sung
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2004년도 ICCAS
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    • pp.2041-2044
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    • 2004
  • A pyroelectric sensor using $PbTiO_3$/P(VDF/TrFE) nanocomposites thin film for sensing materials has been fabricated and evaluated with other commercial pyroelectric sensors that use ceramic materials for sensing. The device was mounted in a TO-5 housing to detect infrared light of 5.5 ~ 14 ${\mu}m$ wavelength. The NEP (noise equivalent power) and specific detectivity D of the device were 1.30 ${\times}$ $10^{-8}$W and 1.53 ${\times}$ $10^7$cm /W respectively under emission energy of 13 ${\mu}$W/c$m^2$ respectively. This result shows a better characteristic than the other commercial pyroelectric infrared sensors.

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Nonvolatile Ferroelectric Memory Devices Based on Black Phosphorus Nanosheet Field-Effect Transistors

  • 이효선;이윤재;함소라;이영택;황도경;최원국
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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    • pp.281.2-281.2
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    • 2016
  • Two-dimensional van der Waals (2D vdWs) materials have been extensively studied for future electronics and materials sciences due to their unique properties. Among them, black phosphorous (BP) has shown infinite potential for various device applications because of its high mobility and direct narrow band gap (~0.3 eV). In this work, we demonstrate a few-nm thick BP-based nonvolatile memory devices with an well-known poly(vinylidenefluoride-trifluoroethylene) [P(VDF-TrFE)] ferroelectric polymer gate insulator. Our BP ferroelectric memory devices show the highest linear mobility value of $1159cm^2/Vs$ with a $10^3$ on/off current ratio in our knowledge. Moreover, we successfully fabricate the ferroelectric complementary metal-oxide-semiconductor (CMOS) memory inverter circuits, combined with an n-type $MoS_2$ nanosheet transistor. Our memory CMOS inverter circuits show clear memory properties with a high output voltage memory efficiency of 95%. We thus conclude that the results of our ferroelectric memory devices exhibit promising perspectives for the future of 2D nanoelectronics and material science. More and advanced details will be discussed in the meeting.

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무가습 가교 가지형 공중합체 전해질 막의 제조 (Preparation of Anhydrous Crosslinked Graft Copolymer Electrolyte Membrane)

  • 노동규;고주환;박정태;서진아;김종학
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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    • pp.270-273
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    • 2009
  • A comb-like copolymer consisting of a poly(vinylidene fluoride-co-chlorotrifluoro-ethylene) backbone and poly(hydroxy ethyl acrylate) side chains, i.e. P(VDF-co-CTFE)-g-PHEA, was synthesized through atom transfer radical polymerization (ATRP) using CTFE units as a macroinitiator. Successful synthesis and a microphase-separated structure of the copolymer were confirmed by proton nuclear magnetic resonance (1H-NMR), FT-IR spectroscopy, and transmission electron microscopy (TEM). This comb-like polymer was crosslinked with 4,5-imidazole dicarboxylic acid (IDA) via the esterification of the -OH groups of PHEA and the -COOH groups of IDA. Upon doping with phosphoric acid ($H_3PO_4$) to form imidazole-$H_3PO_4$ complexes, the proton conductivity of the membranes continuously increased with increasing $H_3PO_4$ content. A maximum proton conductivity of 0.015 S/cm was achieved at $120^{\circ}C$ under anhydrous conditions. In addition, these P(VDF-co-CTFE)-g-PHEA/IDA/$H_3PO_4$ membranes exhibited good mechanical properties (765 MPa of Young's modulus), and high thermal stability up to $250^{\circ}C$, as determined by a universal testing machine (UTM) and thermal gravimetric analysis (TGA), respectively.

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Nonvolatile Ferroelectric P(VDF-TrFE) Memory Transistors Based on Inkjet-Printed Organic Semiconductor

  • Jung, Soon-Won;Na, Bock Soon;Baeg, Kang-Jun;Kim, Minseok;Yoon, Sung-Min;Kim, Juhwan;Kim, Dong-Yu;You, In-Kyu
    • ETRI Journal
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    • 제35권4호
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    • pp.734-737
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    • 2013
  • Nonvolatile ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) memory based on an organic thin-film transistor with inkjet-printed dodecyl-substituted thienylenevinylene-thiophene copolymer (PC12TV12T) as the active layer is developed. The memory window is 4.5 V with a gate voltage sweep of -12.5 V to 12.5 V. The field effect mobility, on/off ratio, and gate leakage current are 0.1 $cm^2/Vs$, $10^5$, and $10^{-10}$ A, respectively. Although the retention behaviors should be improved and optimized, the obtained characteristics are very promising for future flexible electronics.