• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.478.1-478.1
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• 2014

We investigated $MoO_3$ graded ITO electrodes for organic solar cells (OSCs) without PEDOT:PSS buffer layer. The effect of $MoO_3$ thickness on the electrical, optical, and structural properties of $MoO_3$ graded ITO anodes prepared by RF/DC magnetron co-sputtering system using $MoO_3$ and ITO targets was investigated. At optimized conditions, we obtained $MoO_3$ graded ITO electrodes with a low sheet resistance of 13 Ohm/square, a high optical transmittance of 83% and a work function of 4.92 eV, comparable to conventional ITO films. Due to the existence of $MoO_3$ on the ITO electrodes, OSCs fabricated on $MoO_3$ graded ITO electrode without buffer layer successfully operated. Although OSCs fabricated on ITO anode without buffer layer showed a low power conversion efficiency of 1.249%, OSCs fabricated on $MoO_3$ graded ITO electrode without buffer layer showed a outstanding cell performance of 2.545%. OSCs fabricated on the $MoO_3$ graded ITO electrodes exhibited a fill factor of 61.275%, a short circuit current of 7.439 mA/cm2, an open circuit voltage of 0.554 V, and a power conversion efficiency of 2.545%. Therefore, $MoO_3$ graded ITO electrodes can be considered a promising transparent electrode for cost efficient and reliable OSCs because it could eliminate the use of acidic PEDOT:PSS buffer layer.

• 공업화학
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• 제31권3호
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• pp.291-298
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• 2020

본 연구에서는 RF/DC 마그네트론 증착법을 이용하여 실온에서 유리 기판 상에 ZITO/Ag/ZITO 다층막 투명전극을 제조하였다. ZITO/Ag/ZITO (100/8/42 nm)로 이루어진 다층막 구조에 대해, 면저항이 9.4 Ω/㎡이고 550 nm에서 투과도가 83.2%인 투명 전도성 필름이 얻어졌다. ZITO/Ag/ZITO 다층막 필름의 면저항 및 투과도 특성은 적외선(열선)을 효과적으로 차단할 수 있기 때문에 고분자분산액정(polymer-dispersed liquid crystal, PDLC) 기반 스마트 윈도우 적용에 매우 유용함을 알 수 있었으며 이로 인해 에너지 절약형 스마트 유리로서의 응용도 가능할 것으로 판단된다. 제조된 ZITO/Ag/ZITO 다층막 투명전극을 적용한 2관능성 우레탄 아크릴레이트 기반 PDLC 시스템에 있어서 PDLC 층 두께 및 자외선(ultraviolet, UV) 세기 변화가 전기광학적 특성, 광중합 동력학 및 표면 형태학에 미치는 영향을 조사하였다. 15 ㎛의 PDLC 층 두께를 가지며 2.0 mW/c㎡의 UV 세기로 광경화된 PDLC 셀이 우수한 off-state 불투명도, 높은 on-state 투과도 및 양호한 구동 전압을 나타냈다. 또한, 본 연구에서 제조된 최적 조건의 PDLC 기반 스마트 윈도우는 광을 효율적으로 산란시킬 수 있는 2~5 ㎛ 크기의 양호한 마이크로 구조를 갖는 액정 droplet들이 형성되었으며, 이로 인해 우수한 최종 물성을 갖는 PDLC 셀이 제조되었다.

• 조명전기설비학회논문지
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• 제20권7호
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• pp.6-13
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• 2006

각 종 전자 디바이스의 투명전도막으로 많이 사용되는 ITO 및 ZnO:Al 박막을 스퍼터링법에 의해 제작하였다. 가스압력 및 기판온도 등의 최적조건하에서 제작된 ITO 및 ZnO:Al 박막은 각각 $1.67{\times}10^{-3}[{\Omega}-cm]$ 및 $2.2{\times}10^{-3}[{\Omega}-cm]$의 비저항율과 89.61[%] 및 90.88[%]의 가시광 영역에서의 광투과율을 나타내었다. ZnO:Al과 ITO 투명전극을 이용하여 5인치의 PDP 셀을 동일한 제조조건하에서 제작하였다. ZnO:Al의 경우 Ne(base)-Xe(8%)의 가스 혼합비, 그리고 400[Torr]의 압력조건에서 가장 잘 동작되었으며, $200{\sim}300$[V]의 인가전압 범위에서 $836[cd/m^2]$의 평균휘도를 나타내었다. 고휘도 및 저 소비전력특성을 위한 중요한 파라메타인 광효율은 전원 주파수가 $10{\sim}50[Khz]$의 범위에서 $1.2{\sim}1.6[lm/W]$정도를 나타내었으며, ITO의 경우 휘도 및 광 발생 효율은 약 10[%]정도 상승하였다.

• 반도체디스플레이기술학회지
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• 제14권3호
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• pp.51-55
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• 2015

We have fabricated silver nanowire (AgNW) films as a stretchable and transparent electrode on polydimethylsiloxane (PDMS) substrates using a spray coater. Inherently, they show poor surface roughness and stretchability. To tackle it, we have employed a conductive polymer, poly (3,4-ethylenedioxythiophene) : Poly(styrene sulfonate) (PEDOT : PSS). PEDTO : PSS solution is mixed with AgNWs or spin-coated on the AgNW film. Compared with AgNW film only, PEDOT : PSS film only, and polymer-mixed AgNW films, the AgNW/polymer bilayer films exhibit much better surface roughness and stretchability. It is found that spray-coating of AgNWs on uncured PDMS and spin-coating of PEDOT : PSS solution on the AgNW films enhance the surface roughness of electrodes. Such a bilayer structure also provides a stable resistance under tensile strain due to the fact that each layer acts as a detour route for carriers. With this structure, we have obtained the peak-to-peak roughness ($R_{pv}$) as low as 76.8nm and a moderate increase of sheet resistance (from $10{\Omega}/{\Box}$ under 0% strain to $30{\Omega}/{\Box}$ under 40% strain).

• 마이크로전자및패키징학회지
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• 제26권3호
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• pp.37-41
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• 2019

Ag나노와이어 도전성 잉크를 플렉서블한 투명 기판 위에 코팅 후 이러한 여분의 유기물을 $O_2$ 플라즈마를 이용하여 제거함으로써 Ag 나노와이어를 이용한 투명전극의 면저항과 광학적 특성을 최적화하였다. Ag 나노와이어 도전성 잉크를 코팅한 후 30초간 $O_2$ 플라즈마 처리를 하였을 때 면저항은 최대 27 % 정도 감소하였으며, 잔류 유기물의 제거를 통하여 그 광학적 특성도 향상됨을 알 수 있었다. 또한 $O_2$ 플라즈마 처리 시간이 30초 이상 증가할 경우 그 면저항이 오히려 감소함을 확인하였는데, 이는 과도한 $O_2$ 플라즈마로 인하여 Ag나노와이어의 degradation이 일어나는데 그 원인이 있음을 확인하였다.

• 한국재료학회지
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• 제18권12호
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• pp.678-682
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• 2008

This study investigates $Bi_2O_3$-$B_2O_3$-BaO-ZnO glass with variations of the $Co_3O_4$ content (0.25, 0.5, 1, and 2 wt%) and the interaction between transparent dielectric and Ag electrodes heat-treated at $500-560^{\circ}C$ for 30 min. The glass transition temperature, softening temperature and thermal expansion coefficient were $432^{\circ}C$, $460^{\circ}C$ and $81.4{\times}10^{-7}/^{\circ}C$, respectively. The transmittance of 0.25 wt% $Co_3O_4$ to which dielectric was added was highest and was decreased due to coloration with the addition of more than 0.25 wt%. However, without $Co_3O_4$, the transmittance of the transparent layer was decreased due to the formation of $Ba_5Bi_3$; however, the occurrence of the crystal phase decreased as a result of the addition of $Co_3O_4$. The amount of $Co^{2+}$ ions increased as the $Co_3O_4$ increased. With a maximum of $Co^{3+}$ ions, the highest transmittance was observed.

• 한국전기전자재료학회논문지
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• 제30권3호
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• pp.162-169
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• 2017

Indium tin oxide (ITO) thin films show a low sheet resistance and high transmittance in the visible range of the spectrum. Therefore, they play an important role as transparent electrodes for flat panel displays. However, their resistivity is rather high for use as a transparent electrode in large displays. One way to improve electrical and optical properties in large displays is to use ITO/Ag/ITO multilayer films. ITO/Ag/ITO multilayer films have lower sheet resistance than single layer ITO films with the same thickness. Prior to the ITO/Ag/ITO multilayer experiments, optimal condition for thickness change are necessary. Their thicknesses were deposited differently in order to analyze electrical and optical properties. However, when optimal single film characteristics are applied to ITO/Ag/ITO multilayer films, other phenomena appeared. After analyzing the electrical and optical properties by changing ITO and Ag film thickness, ITO/Ag/ITO multilayer films were optimized. By combining ITO film at $586\;{\AA}$ and Ag film at 10 nm, the ITO/Ag/ITO multilayer films showed optimized high optical transmittance of 87.65%, and the low sheet resistance of $5.5{\Omega}/sq$.

• 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.

• 마이크로전자및패키징학회지
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• 제21권2호
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• pp.1-11
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• 2014

Flexible transparent conductive electrodes (TCEs) have recently attracted a great deal of attention owing to rapid advances in flexible electronic devices, such as flexible displays, flexible photovoltanics, and e-papers. As the performance and reliability of flexible electronics are critically affected by the quality of TCE films, it is imperative to develop TCE films with low resistivity and high transparency as well as high flexibility. Indium tin oxide (ITO) has been the most dominant transparent conducting material due to its high optical transparency and electrical conductivity. However, ITO is susceptible to cracking and delamination when it is bent or deformed. Therefore, various types of flexible TCEs, such as carbon nanotube, conducting polymers, graphene, metal mesh, Ag nanowires (NWs), and metal mesh have been extensively investigated. Among several options to replace ITO film, Ag NWs and metal mesh have been suggested as the promising candidate for flexible TCEs. In this paper, we focused on Ag NWs and metal mesh, and summarized the current development status of Ag NWs and metal mesh. The several critical issues such as high contact resistance and haze are discussed, and newly developed technologies to resolve these issues are also presented. In particular, the flexibility and durability of Ag NWs and metal mesh was compared with ITO electrode.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.490.1-490.1
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• 2014

The ZnO nanowire (NW)-based nanogenerators (NGs) can have rectifying current and potential generated by the coupled piezoelectric and semiconducting properties of ZnO by variety of external stimulation such as pushing, bending and stretching. So, ZnO NGs needed to enhance durability for stable properties of NGs. The durability of the metal electrodes used in the typical ZnO nanogenerators(NGs) is unstable for both electrical and mechanical stability. Indium tin oxide (ITO) is used as transparent flexible electrode but because of high cost and limited supply of indium, the fragility and lack of flexibility of ITO layers, alternatives are being sought. It is expected that carbon nanotube and Ag nanowire conductive coatings could be a prospective replacement. In this work, we demonstrated transparent flexible ZnO NGs by using CNT/Ag nanowire hybrid electrode, in which electrical and mechanical stability of top electrode has been improved. We grew vertical type ZnO NW by hydrothermal method and ZnO NW was coated with hybrid silicone coating solution as capping layer to enhance adhesion and durability of ZNW. We coated the CNT/Ag nanowire hybrid electrode by using bar coating system on a capping layer. Power generation of the ZnO NG is measured by using a picoammeter, a oscilloscope and confirmed surface condition with FE-SEM. As a results, the NGs using the CNT/Ag NW hybrid electrode show 75% transparency at wavelength 550 nm and small change of the resistance of the electrode after bending test. It will be discussed the effect of the improved flexibility of top electrode on power generation enhancement of ZnO NGs.