• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.121-121
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• 2018

Copper is a promising electronic material due to low cost and high electrical conductivity. However, the oxidation problem in an ambient condition makes a crucial issue in practical applications. In here, we developed a simple and cost-effective Cu patterning method on a flexible PET film by combining a solution processable Cu nanoparticle patterning and a low temperature post-processing using acetic acid treatment, laser sintering process and acid-assisted laser sintering process. Acid-assisted laser sintering processed Cu electrode showed superior characteristics in electrical, mechanical and chemical stability over other post-processing methods. Finally, the Cu electrode was applied to the flexible electronics applications such as flexible and transparent heaters and touch screen panels.

• 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.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1575-1577
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• 2009

We have investigated the characteristics of transparent indium zinc oxide(IZO)/Ag/IZO multilayer electrode grown on polyethylene terephthalate (PET) substrates using a specially designed roll-to-roll sputtering system for use in flexible device are described. By the continuous R2R sputtering of the bottom IZO, Ag, and top IZO layers at room temperature, we were able to fabricate an IZO-Ag-IZO multilayer electrode with a sheet resistance of 6.15 ${\Omega}$/square, optical transmittance of 87.4 %, and figure of merit value of 42.03 10-3 ${\Omega}$-1. In addition, the IZO-Ag-IZO multilayer electrode exhibited superior flexibility to the RTR sputter grown single ITO electrode, due to the existence a ductile Ag layer between the IZO layers. This indicates that the RTR sputtered IZO-Ag-IZO multilayer is a promising flexible electrode that can substitute for the conventional single ITO electrode grown by bath type sputtering for use in low cost flexible device, due to its low resistance, high transparency, superior flexibility and fast preparation by the R2R process.

• 마이크로전자및패키징학회지
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• 제27권1호
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• pp.9-15
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• 2020

The 'field-effect' underlies the operation of most conventional electronic devices. However, effective control and implementation of the field-effect in semiconductor devices are limited due to screening of the electric-field by conducting electrodes. Thus far, the electronic devices have necessarily been designed to avoid or minimize the electric-field screening effect. As an alternative approach to this, a new type of conducting electrodes which would be transparent to both visible light and electric-field while being electrically conductive have been developed. Here, we define these electrodes as 'electric-field transparent electrodes' and provide a review on related work. Particular attention is paid to the material selection and design strategies to enhance the electric-field transparency of the electrodes while maintaining good electrical conductivity and optical transparency. We then introduce potential applications of the electric-field transparent electrodes in electronic and optoelectronic devices.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.314-314
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• 2013

Recently, flexibility is one of the hottest issues in the field of electronic devices. For flexible displays or solar cells, a development of transparent conductive electrodes (TCEs) with flexibility, bendability and foldability is an essential element. Hundreds of nanometers indium-tin-oxide (ITO) films have been widely used and commercialized as a transparent electrode, but their brittleness make them difficulty to apply flexible electronics. Many researchers have been studying for flexible TCEs such as a few layers of graphene sheets, carbon nanotube networks, conductive polymer films and combinations among them. Although gained flexibility, their transmittance and resistivity have not reached those of commercialized ITO films. Metal grids electrode cannot act as TCEs only, but they can be used to lower the resistance of TCEs with few losses of transmittance. However, the possibility of device shortage will be rise at the devices with metal grids because a surface flatness of TCEs may be deteriorated when metal grids are introduced using conventional methods. In our research, we have developed hybrid TCEs, which combined tens of nanometers ITO film and metal grids which are embedded in flexible substrate. They show $13{\Omega}$/${\Box}f$ sheet resistance with 94% of transmittance. Moreover, the sheet resistance was maintained up to 1 mm of bending radius. Also, we have verified that flexible organic light emitting diodes and organic solar cells with the TCEs showed similar performances compared to commercial ITO (on glass substrate) devices.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.217.2-217.2
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• 2014

We prepared a flexible and transparent CuO/Cu/CuO multilayer electrodes on a polyethylene terephthalate (PET) substrate using a specially designed roll-to-roll sputtering system at room temperature for GFF-type touch screen panels (TSPs). By the continuous roll-to-roll sputtering of the CuO and Cu layer, we fabricated a flexible CuO(150nm)/Cu(150nm)/CuO(150nm) multilayer electrodes with a sheet resistance of $0.289{\Omega}/square$, resistivity of $5.991{\times}10^{-23}{\Omega}-cm$, at the optimized condition without breaking the vacuum. To investigate the feasibility of the CuO/Cu/CuO multilayer as a transparent electrode for GFF-type TSPs, we fabricated simple GFF-type TSPs using the diamond patterned CuO/Cu/CuO electrode on PET substrate as function of mesh line width. Using diamond patterned CuO/Cu/CuO electrode of mesh line $5{\mu}m$ with sheet resistance of 38 Ohm/square, optical transmittance of 90% at 550 nm and an average transmittance of 89% at wavelength range from 380 to 780 nm, we successfully demonstrated GFF-type touch panel screens (TPSs). The successful operation of GFF-type TPSs with CuO/Cu/CuO multilayer electrodes indicates that the CuO/Cu/CuO multilayer is a promising transparent electrode for large-area capacitive-type TPSs due to its low sheet resistance and high transparency.

• 한국응용과학기술학회지
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• 제38권6호
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• pp.1553-1560
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• 2021

본 연구는 나노섬유를 제조하는데 빠르고 효과적인 전기방사법을 이용하여 PVA(Polyvinyl alcohol)와 AgNO₃를 혼합하여 제조한 용액을 금속산화물 기반 나노 섬유로 이루어진 투명 전극을 제조하고 그 특성을 분석하였다. PVA/AgNO₃ 혼합 용액을 전기방사법을 이용하여 유리기판 위에 나노섬유 구조체 형태로 방사하여 250 ℃에서 2 시간 동안 열처리 과정을 통해 전기 전도성이 향상된 은나노 섬유 기반 투명 전극을 제조하였다. 제조된 투명전극은 four-point probe 장비를 이용하여 전기적 특성을 분석하였으며, UV - Vis spectrophotometer 를 이용하여 제조된 투명전극의 투과도를 확인하였다. 또한, Scanning Electron Microscopy (SEM)과 Energy Dispersive Spectrometer(EDS)를 통해 은 나노 섬유의 표면 특성과 성분을 확인하였다. 이러한 분석들을 통해, 전기 방사 시간에 따른 면 저항과 투과도의 최적화된 조건을 확인할 수 있었으며, 은 나노 섬유로 이루어진 투명 전극은 전기적, 광학적, 기계적 특성이 우수하여 태양전지, 디스플레이, 터치스크린과 같은 차세대 유연 디스플레이에 적용 가능성을 보여주었다.

• 멤브레인
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• 제33권5호
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• pp.248-256
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• 2023

ITO 투명 전극 필름은 디스플레이, 전기 자동차 등 산업 전 범위에서 널리 사용되는 전자 재료이다. 본 연구에서는 이러한 indium tin oxide (ITO) 필름의 열성형 안정성을 향상시키기 위하여 Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) 전도성 고분자 코팅 용액 조성을 결정하였다. 1000 S/cm의 고 전도성을 보이는 PEDOT:PSS 용액에 끓는점이 각기 다른 4가지 종류의 용매를 희석하였고, 코팅 전 후 면저항 변화를 분석하였다. 또한 380~800 nm 영역의 광 투과율 분석 및 Raman 스펙트럼 분석을 통하여 PEDOT:PSS 박막이 코팅된 ITO 투명 전극의 전기적 특성 결정 메커니즘을 규명하였다. 230℃ 열성형 공정 결과 ITO 필름은 113% 연신 상태에서 이미 전기 전도성을 읽었지만, ethylene glycol을 희석 용매로 사용하여 얻어진 전도성 고분자 박막이 적용된 ITO 필름은 126% 고 연신 상태에서도 초기 60 Ω/sq 면저항을 246 Ω/sq로 유지하는 우수한 전기 전도성을 보였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.813-815
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• 2008

We prepared highly transparent and conductive Oxide/Metal/Oxide(OMO) multilayer by sputtering and developed wet etching process of OMO with a clear edge shape for the first time. The transmittance and sheet-resistance of the OMO are about 89% and $3.3\;{\Omega}/sq.$, respectively. We adopted OMO as a gate electrode of transparent TFT (TTFT) array and integrated OLED on top of the TTFT to result in high aperture ratio of bottom emission AM-OLED.

• 마이크로전자및패키징학회지
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• 제30권2호
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• pp.21-32
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• 2023

구리 나노와이어(CuNW)는 전기 전도도가 우수할 뿐만 아니라 높은 기계적 유연성과 비용 효율성 등의 장점이 있다. 그러나 구리 나노와이어는 산화가 쉽게 일어나기 때문에 투명 전극의 특성까지도 저하될 수 있다는 단점 또한 존재한다. 따라서, 이러한 문제점을 해결하기 위한 연구들이 진행되고 있다. 이에 본 고에서는 탄소 기반 물질, 금속, 전도성 고분자 등의 코팅용 소재를 활용하여 구리 나노와이어 투명전극의 산화를 방지하고 안정성을 향상시키기 위한 다양한 방법과 연구를 소개한다. 이를 통해 구리 나노와이어 기반 기술의 발전과 산화에 대한 문제를 해결할 수 있는 방안들을 제공하고자 한다.