• Journal of the Korean Ceramic Society
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• v.52 no.1
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• pp.72-76
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• 2015

150-nm-thick In-Zn-Tin-Oxide (IZTO) films were deposited by RF magnetron sputtering after a 10 to 50-nm-thick $SiO_2$ buffer layer was deposited by plasma enhanced chemical vapor deposition (PECVD) on polyethylene terephthalate (PET) substrates. The electrical, structural, and optical properties of the IZTO/$SiO_2$/PET films were analyzed with respect to the thickness of the $SiO_2$ buffer layer. The mechanical properties were outstanding at a $SiO_2$ thickness of 50 nm, with a resistivity of $1.45{\times}10^{-3}{\Omega}-cm$, carrier concentration of $8.84{\times}10^{20}/cm^3$, hall mobility of $4.88cm^2/Vs$, and average IZTO surface roughness of 12.64 nm. Also, the transmittances were higher than 80%, and the structure of the IZTO films were amorphous, regardless of the $SiO_2$ thickness. These results indicate that these films are suitable for use as a transparent conductive oxide for transparency display devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.6
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• pp.408-411
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• 2018

We fabricated highly flexible Mn-doped $SnO_2$ (MTO)/Ag/MTO/polydimethylsiloxane (PDMS)/MTO multilayer transparent conducting films. To reduce refractive-index mismatching of the MTO/Ag/MTO/polyethylene terephthalate (PET), index-matching layers were inserted between the oxide-metal-oxide-structured films and the PET substrate. The PDMS layer was deposited by spin-coating after adjusting the mixing ratio of PDMS and hexane. We investigated the effects of the index-matching layer on the color and reflectance differences with different PDMS dilution ratios. As the dilution ratio increased from 1:100 to 1:130, the color difference increased slightly, while the reflectance difference decreased from 0.62 to 0.32. The MTO/Ag/MTO/PDMS/MTO film showed a transmittance of 87.18~87.68% at 550 nm. The highest value of the Haacke figure of merit was $47.54{\times}10^{-3}{\Omega}^{-1}$ for the dilution ratio of 1:130.

• Industry Promotion Research
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• v.9 no.1
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• pp.21-29
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• 2024

In the rapidly advancing information society, electronic devices, including smartphones and tablets, are increasingly digitized and equipped with high-performance features such as flexible displays. This study focused on optimizing the manufacturing process for Transparent Conductive Films (TCF) by using the cost-effective conductive polymer PEDOT and transparent substrate PET as alternatives to expensive materials in flexible display technology. The variables considered are production speed (m/min), coating maximum temperature (℃), and PEDOT supply speed (rpm), with surface resistivity (Ω/□) as the response parameter, using Response Surface Methodology (RSM). Optimization results indicate the ideal conditions for production: a speed of 22.16 m/min, coating temperature of 125.28℃, and PEDOT supply at 522.79 rpm. Statistical analysis validates the reliability of the results (F value: 18.37, P-value: < 0.0001, R²: 0.9430). Under optimal conditions, the predicted surface resistivity is 145.75 Ω/□, closely aligned with the experimental value of 142.97 Ω/□. Applying these findings to mass production processes is expected to enhance production yields and decrease defect rates compared to current practices. This research provides valuable insights for the advancement of flexible display manufacturing.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1535-1537
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• 2009

High performance resistive type touch panel was fabricated on flexible polyethylene terephthalate (PET) substrates coated with Al- and Ga-codoped ZnO (AGZO) films. The AGZO films were deposited by roll-to-roll direct current magnetron sputter at room temperature. The AGZO thin films on PET substrates showed high transparency (> 85 % at 550 nm) and low sheet resistance (450 ${\Omega}$/sq.). These values were similar to those of commercial ITO films used for resistive type touch panel.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.11
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• pp.961-968
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• 2009

In this work, transparent conductive oxide(TCO) films such as $In_2O_3-SnO_2$(ITO) and $In_2O_3-ZnO$(IZO) were prepared on polyethylene naphthalene(PEN) and glass substrates by using rf-magnetron sputtering system. The TCO films deposited on PEN substrate show very poor conductivity as compared to that of the TCO films deposited on glass substrates. From the results of the residual gas analysis(RGA) test, this poor stability of plastic substrate is presumed to be caused by the deteriorated adhesion between the TCO films and the plastic substrate due to outgassing from the plastic substrate during deposition of TCO films. From our experiment, it is found that the vaporization of some defects in the plastic substrates deteriorate the adhesion of the TCO films to the plastic substrate, because the most plastic substrates containing the water vapor and/or other adsorbed particles such as organic solvents. Mixing of these gases vaporized in the sputtering process will also affect the electrical property of the deposited TCO films. Inorganic thin composite $(SiO_2)_{40}(ZnO)_{60}$ film as a gas barrier layer is coated on the PEN substrate to protecting the diffusion of vapors from the substrate, so that the TCO films with an improved quality can be obtained.

• Food Science and Preservation
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• v.22 no.5
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• pp.623-628
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• 2015

Fresh cut vegetables provide convenience and rapidity to consumers. However, they have a weakness with respect to their short shelf-life due to browning and quality degradation via increased respiration. To overcome this problem, the effect of packaging film on the short-term storage of cut kimchi cabbages was investigated. Polypropylene (PP), oriented polypropylene (OPP), and low-density polyethylene (LDPE) films were used as packaging film, and cut kimchi cabbages were stored in the packaging films at $5^{\circ}C$ for 4 weeks. PP film packaging showed the least weight loss and soluble solids loss after 4 weeks. Titratable acidity increased during storage for all samples, however, the increase rate of titratable acidity in PP and OPP film packaging decreased, which was lower than that of LDPE film packaging. Color values decreased over time during storage. In appearance, PP film packaging was better than other films due to their high transparency. In a sensory test, there was no statistical difference among samples. Taken together, the transparent PP film packaging was more effective for short-term storage of cut kimchi cabbages. Thus, this study provides useful information for the selection of packaging materials for cut kimchi cabbage marketing.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.2
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• pp.150-156
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• 2001

To explore the feasibility of recycled paper mulching in spring-grown potato the changes of soil environments and the growth and yield of potato under non-mulched control and three mulching treatments of recycled paper (RPM), transparent polyethylene film (TPFM), and black polyethylene film (BPFM) were examined over two spring seasons in 1998 and 1999 at Suwon, Korea. The mulching materials were a recycled mulch paper with 110 g/$m^2$ and a thickness of 0.1mm, which was manufactured from old corrugated containers for this experiment and the commercial polyethylene films with a thickness of 0.01mm. RPM lowered the average soil temperature at 5-cm depth during the potato growing period by 03$^{\circ}C$ compared with the control, whereas TPFM and BPFM raised it by 2.$0^{\circ}C$, and 1.8$^{\circ}C$, respectively. On a sunny day during sprout emergence, RPM reduced the maximum soil temperature by about 5$^{\circ}C$, while TPFM and BPFM enhanced it by about 11$^{\circ}C$ and 6.$0^{\circ}C$, respectively. The temperature difference between the control and the mulching treatments decreased with the development of canopy. All the mulching treatments had an advantage in preserving the soil moisture over the control. RPM and BPFM resulted in the effective control of weed by obstructing light transmission onto soil surface, but TPFM had no control effect of weed. Sprout emergence started two to three days earlier in TPFM and BPFM, but one day later in RPM than in the control due to the altered soil temperature by the mulching treatments. However, the final percentage of emergence was notably lower in TPFM than that in the control because of too high soil temperature during daytime, but was not different among the control, RPM, and BPFM. During the early stage of potato growth, the shoot and root growth under RPM was lower compared with the control, but afterwards, RPM outpaced the control. In 1998 experiment, the tuber yield under RPM and BPFM were significantly higher than those of the control and TPFM. In 1999 experiment, there was no significant difference in tuber yield between RPM and the control.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.282-282
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• 2013

그래핀(Graphene)은 열 전도도가 높고 전자 이동도(200 000 cm2V-1s-1)가 우수한 전기적 특성을 가지고 있어 차세대 전자재료로써 유망한 후보로 간주되어 왔다. 최근에는 아크 방출(Arc discharge method), 화학적 기상 증착법(Chemical vapor deposition; CVD), 이온-조사법(Ion-irradiation) 등을 이용한 이종원자(Hetero atom)도핑과 화학적 처리를 이용한 기능화(Functionalization)등의 방법으로 그래핀의 전도도를 향상시킬 수 있었다. 그러나 이러한 방법들은 기판의 표면을 거칠게 하며, 그래핀에 많은 결함들이 발생한다는 단점이 있다. 이러한 단점을 극복하기 위해 자가 조립 단층막법(Self-Assembled Monolayers; SAMs)을 이용하여 기판을 기능화한 후 그 위에 그래핀을 전사하면, 자가 조립 단층막의 기능기에 따라 그래핀의 일함수를 조절 가능하고 운반자 농도나 도핑 유형을 변화시켜 소자의 전기적 특성을 최적화 할 수 있다 [1-3]. 본 연구에서는 PET(polyethylene terephthalate) 기판에 SAMs를 이용하여 유연하고 투명한 그래핀 전극을 제작하였다. 자외선 오존처리 (UV ozone treatment)를 이용하여 PET 기판 표면 위에 하이드록실 기(Hydroxyl group; -OH)를 기능화 화였고 이를 접촉각 측정(Contact angle measurement)을 통해 확인하였다. 또한 3-Aminopropyltriethoxysilane(APTES)와 톨루엔 (toluene)을 이용하여 PET 기판 표면 위의 하이드록실 기 위에 아민 기(Amine group; -NH2)를 기능화 하였고 이를 X-선 광전자 분광법(X-ray photoelectron spectroscopy: XPS)으로 분석하였다. 이렇게 만들어진 PET기판 표면 위에 화학적 기상 증착법을 이용하여 합성한 대면적의 균일한 그래핀을 전사하였다. NH2그룹에 의해 그래핀에 도핑 효과가 나타난 것을 라만 분광법(Raman spectroscopy)과 전류-전압 특성곡선(I-V characteristic curve)을 이용하여 확인하였다. 본 연구 결과는 유연하고 투명한 기판 위에 안정적이면서 패턴이 가능하기 때문에 그래핀을 기반으로 하는 반도체 소자에 적용 가능할 것이라 예상된다.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1799-1805
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• 2014

In this article, we described about the preparation and electrochemical properties of a flexible energy storage system based on a plastic polyethylene terephthalate (PET) substrate. The PET treated with UV/ozone was fabricated with multilayer films composed of 30 polyaniline (PANi)/graphene oxide (GO) bilayers using layer-by-layer assembly of positively charged PANi and negatively charged GO. The conversion of GO to the reduced graphene oxide (RGO) in the multilayer film was achieved using hydroiodic acid vapor at $100^{\circ}C$, whereby PANi structure remained nearly unchanged except a little reduction of doping state. Cyclic voltammetry and charge/discharge curves of 30 PANi/RGO bilayers on PET substrate (shorten to PANi-$RGO_{30}$/PET) exhibited an excellent volumetric capacitance, good cycling stability, and rapid charge/discharge rates despite no use of any metal current collectors. The specific capacitance from charge/discharge curve of the PANi-$RGO_{30}$/PET electrode was found to be $529F/cm^3$ at a current density of $3A/cm^3$, which is one of the best values yet achieved among carbon-based materials including conducting polymers. Furthermore, the intrinsic electrical resistance of the PANi-$RGO_{30}$/PET electrodes varied within 20% range during 200 bending cycles at a fixed bend radius of 2.2 mm, indicating the increase in their flexibility by a factor of 225 compared with the ITO/PET electrode.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.380.1-380.1
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• 2014

열 화학기상증착법은 여러 가지 그래핀의 제작방법 중 대면적으로 양질의 그래핀을 효과적으로 합성할 수 있는 방법으로 널리 이용되고 있다. 이 방법으로 그래핀을 합성할 경우, 주요 변수로 성장 온도와 촉매 금속이 있으며 이를 적절히 조절함으로써 합성되는 그래핀의 결정성과 층수를 조절할 수 있다[1-3]. 본 연구에서는 탄소 용해도가 작은 두꺼운 촉매 금속 기판 위에 선택적인 위치에 탄소 용해도가 큰 얇은 촉매 금속을 증착하여 그래핀의 층수를 적절하게 제어하고자 한다. 그래핀을 합성하기 위해 온도를 증가시키는 과정에서 두 층의 촉매 금속은 표면 에너지를 낮추기 위해 합금을 형성하게 되며, 이 때 탄소 용해도가 변화할 것으로 예상된다. 이 변화하는 탄소 용해도에 맞추어 탄소 공급원인 메탄 가스를 주입하는 시기를 적절히 조절하게 되면, 합성되는 그래핀의 층수 조절이 가능할 것이라 예상한다. 탄소 용해도가 큰 금속으로 니켈을, 탄소 용해도가 작은 금속으로 구리를 선택하였다. 우선 니켈의 확산 거리를 계산하여 메탄 가스를 주입하는 적절한 온도를 결정하였으며, 이 온도를 기준으로 표면에서의 니켈의 함량을 분석하였다. 니켈의 함량과 표면에서의 탄소의 구성비의 관계를 조사한 결과, 본 실험에서 이용한 방법으로 그래핀의 층수를 조절하는 것이 가능하다는 것을 확인하였다.