• Advances in nano research
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• v.14 no.4
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• pp.329-334
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• 2023

Organic ferroelectric material found vast application in a verity of engineering and health technology fields. In the present study, we investigated the application of the deformable organic ferroelectric in motion measurement and improving performance in tennis players. Flexible ferroelectric material P(VDF-TrFE) could be used in wearable motion sensors in tennis player transferring velocity and acceleration data to collecting devises for analyzing the best pose and movements in tennis players to achieve best performances in terms of hitting ball and movement across the tennis court. In doing so, ferroelectric-based wearable sensors are used in four different locations on the player body to analyze the movement and also a sensor on the tennis ball to record the velocity and acceleration. In addition, poses of tennis players were analyzed to find out the best pose to achieve best acceleration and movement. The results indicated that organic ferroelectric-based sensors could be used effectively in sensing motion of tennis player which could be utilized in the optimization of posing and ball hitting in the real games.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.2
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• pp.126-132
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• 2017

The power conversion efficiency of organic polymer solar cells was enhanced by introducing a ferroelectric polymer layer at the interface between active layer and metal electrode. The power conversion efficiency was increased by 50% through the enhancement of the open circuit voltage. To investigate the role of the ferroelectric layer on the dissociation process of the excitons, non-radiative portion of the exciton decay was directly measured by using photoacoustic technique. The results show that the ferroelectric nature of the buffer layer does not play any roles on the dissociation process of the excitons, which indicates the efficiency enhancement is not due to the ferroelectricity of the buffer layer.

• Journal of Semiconductor Engineering
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• v.1 no.1
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• pp.38-45
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• 2020

With the recent emergence of foldable electronic devices, interest in flexible organic memory is significantly growing. There are three types of flexible organic memory that have been researched so far: floating-gate (FG) memory, ferroelectric field-effect-transistor (FeFET) memory, and resistive memory. Herein, performance parameters and operation mechanisms of each type of memory device are introduced, along with a brief summarization of recent research progress in flexible organic memory.

• Journal of the Semiconductor & Display Technology
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• v.19 no.2
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• pp.72-76
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• 2020

The author demonstrated organic ferroelectric thin-film transistors with ferroelectric materials of P(VDF-TrFE) and an amorphous oxide semiconducting In-Ga-Zn-O channel on the silicon substrates. The organic ferroelectric layers were deposited on an oxide semiconductor layer by Langmuir-Blodgett method and then annealed at 128℃ for 30min. The carrier mobility and current on/off ratio of the memory transistors showed 9 ㎠V^-1s^-1 and 6 orders of magnitude, respectively. We can conclude from the obtained results that proposed memory transistors were quite suitable to realize flexible and werable electronic applications.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.9
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• pp.589-594
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• 2016

P3HT:PCBM bulk heterojunction solar cells added with ferroelectric polymer were fabricated and characterized. By incorporating P3HT:PCBM solar cell with P(VDF-TrFE) ferroelectric additive, the power conversion efficiency was increased up to nearly 50%. Photoacoustic analysis on this phenomena was carried out for the first time. Through this study, we find that the ferroelectricity of the polymer additive plays the key role in the enhancement of the power conversion efficiency of the organic solar cell by suppressing the non-radiative recombination of charge transfer exciton more effectively.

• Journal of the Korean Ceramic Society
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• v.37 no.7
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• pp.665-672
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• 2000

The ferroelectric YMnO3 thin films were prepared by MOD(metal-organic decomposition) method with Y- and Mn-acetylacetonate as starting materials. Thin films were grown on various substrates by spin-coating technique. The crystalline phases of the thin films were identified by X-ray diffractometer as a function of heat-treatment temperature, pH of coating solution and substrate. In addition, the effect of Mn/Y molar ratio(0.8~1.2) on the formation of hexagonal-YMnO3 phase was investigated. In forming highly c-axisoriented hexagonal-YMnO3 single phase, the Pt coated Si substrate was more effective than the bare Si substrate, and the optimum heat-treatment condition was at 82$0^{\circ}C$ for 30 min. Higher Mn/Y molar ratio within 0.8~1.2 and pH of YMnO3 precursor solution within 0.5~2.5 favored formation of ferroelectric hexagonal phase rather than orthorhombic phase. Leakage current density of the hexagonal-YMnO3 thin film formed on Pt(111)/TiO2/SiO2/Si substrate was low enough as 0.4~4.0$\times$10-8(A/$\textrm{cm}^2$) at 5 V and its remanent polarization(Pr), calculated from the P-E hysteresis loop, was 3 nC/$\textrm{cm}^2$.

• Journal of IKEEE
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• v.22 no.1
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• pp.209-212
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• 2018

In this work, we developed P(VDF-TrFE) organic/ferroelectric material based metal-ferroelectric-metal (MFM) capacitors in order to improve the switching characteristics of gallium nitride (GaN) heterojunction field-effect transistors (HFET). The 27 nm-thick P(VDF-TrFE) MFM capacitors exhibited about 60 ~ 96 pF capacitance with a polarization density of $6{\mu}C/cm^2$ at 4 MV/cm. When the MFM capacitor was connected in series with the gate electrode of GaN HFET, the subthreshold slope decreased from 104 to 82 mV/dec.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1229-1232
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• 2004

The ratio of optimized concentration on optical characteristics for phase-separated composite organic films (PSCOF) liquid crystal display is 30% of pre-polymer (NOA65) and 70% of ferroelectric liquid crystal (Felix). The layer structure in ferroelectric liquid crystal cell made by 30% NOA65 and 70% Felix materials is tilt-bookshelf layer structure. The angle of tilt-bookshelf structure are 17$^{\circ}$, 12$^{\circ}$ which are almost same of tilt angle of ferroelectric liquid crystal in Sm $C^{\ast}$ phase. We know that this result is from compensating the layer buckling. In this paper, we will discuss the effect of layer structure in PSCOF cell on ratio of concentration between pre-polymer and liquid crystal by x-ray measurements. We believe that technology of PSCOF is a good solution to solve the problems of align-defect and mechanical shock for future TV application and plastic LCD.

• Journal of the Korean Ceramic Society
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• v.42 no.11 s.282
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• pp.763-769
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• 2005

Ferroelectric $ReMnO_3$(Re:Ho, Er) thin films were deposited on Si(100) substrate by Metal-Organic Chemical Vapor Deposition (MOCVD). Crystallinity and electric properties of $ReMnO_3$(Re:Ho, Er) thin films were investigated as a function of thermal heat treatment process, CHP (Conventional Heat-treatment Process) and RTP (Rapid Thermal Process). $ReMnO_3$(Re:Ho, Er) thin films prepared by RTP showed higher c-axis preferred orientation and homogeneous surface roughness than those prepared by CHP. The remnant polarization of ferroelectric hysteresis loop of $ReMnO_3$(Re:Ho, Er) thin films was strongly dependent on the c­axis preferred orientation of hexagonal single phase, and the leakage current characteristics of thin films were dependent on the homogeneity of grain size as well as surface roughness of thin films.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.6
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• pp.799-803
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• 2018

We demonstrated memory thin-film transistors (MTFTs) with organic ferroelectric polymer poly(vinylidene fluoride-co-trifluoroethylene) and an amorphous oxide semiconducting indium gallium zinc oxide channel on the elastomeric substrate. The dielectric constant for the P(VDF-TrFE) thin film prepared on the elastomeric substrate was calculated to be 10 at a high frequency of 1 MHz. The voltage-dependent capacitance variations showed typical butterfly-shaped hysteresis behaviors owing to the polarization reversal in the film. The carrier mobility and memory on/off ratio of the MTFTs showed $15cm^2V^{-1}s^{-1}$ and $10^6$, respectively. This result indicates that the P(VDF-TrFE) film prepared on the elastomeric substrate exhibits ferroelectric natures. The fabricated MTFTs exhibited sufficiently encouraging device characteristics even on the elastomeric substrate to realize mechanically stretchable nonvolatile memory devices.