Fabrication of silver nanowire-based stretchable electrodes using spray coating

Lee, J.Y.,Shin, D.,Park, J. Elsevier Sequoia 2016 THIN SOLID FILMS - Vol.608 No.-

We have fabricated silver nanowire (AgNW) films on polydimethylsiloxane (PDMS) substrates using a spray coater for the applications of a stretchable and transparent electrode. Inherently, they show poor surface roughness and weak adhesion to substrates. To tackle it, we have performed a direct spray coating of AgNWs on uncured PDMS in such a way that AgNWs penetrate into the uncured PDMS, thereby enhancing the surface morphology and adhesion properties of AgNW electrodes. However, the standalone AgNW films show an unstable resistance under tensile strain. We have therefore employed a conductive polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), which is coated atop the AgNW film. Such a bilayer configuration ensures a stable resistance under strain because the over-coating layer of PEDOT:PSS effectively suppresses the protrusion of AgNWs from PDMS. It exhibits a moderate increase of sheet resistance (by a factor of ~2) with increasing tensile strain (up to 40%) and number of stretching cycles (up to 100cycles).

AgNWs networks for high-performing transparent heaters by using NiO window layer

Patel, Malkeshkumar,Chauhan, Khushbu R.,Kim, Joondong,Kim, Jong-Woong,Lim, Donggun Elsevier 2017 Sensors and actuators. A, Physical Vol.267 No.-

<P><B>Abstract</B></P> <P>We demonstrate the high-performing silver nanowire (AgNW) networks for transparent heaters by using a NiO window layer. The colorless polyimide (cPI) was used as a substrate in order to configure the transparent heater of NiO/AgNWs/cPI, having over 77% transmittance at a wavelength of 550nm. AgNWs networks were formed on the cPI substrate and the NiO layer was reactively sputtered onto AgNWs at a room temperature. Due to the NiO capping layer onto AgNWs, the electrical and optical properties of AgNW networks were preserved. An extremely high-performing AgNWs-based transparent heater was achieved by utilizing NiO protective. The NiO window layer provides an excellent atmospheric isolation for partially-embedded silver nanowires and makes the heater operation to be stable at high temperatures of 185.5°C with a relatively small bias of 7V. The excellent performances are attributed to the Schottky barrier formed between the NiO window and AgNW networks. The efficient exploitation of capping layers, such as NiO in this study will boost the viability of AgNW-based heaters and electronic devices for commercial applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High-performing transparent heater was formed by AgNWs and NiO layer. </LI> <LI> NiO layer efficiently protected AgNWs from deformation. </LI> <LI> NiO functional window effectively controlled the electrical and thermal properties. </LI> <LI> 200°C was reached by applying 7V for stable operation. </LI> </UL> </P>

Silver Nanowire 기반 Stretchable 투명 전극

이진영,김수연,정다혜,신동균,유수호,서화일,박종운 한국반도체디스플레이기술학회 2015 반도체디스플레이기술학회지 Vol.14 No.3

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 (Rpv) as low as 76.8nm and a moderate increase of sheet resistance (from 10Ω/□ under 0% strain to 30Ω/□ under 40% strain).

Characterization of silver nanowire flexible transparent electrode with grid pattern formed via thermocompression

Jong-Seol Park,Tae-Gon Park,Jin-Seok Park 대한금속·재료학회 2021 ELECTRONIC MATERIALS LETTERS Vol.17 No.3

In this study, we present a new and simple method that utilizes post-processing such as thermal treatment and mechanicalcompression to manufacture a grid patterned silver nanowire (AgNW) fl exible transparent electrode with low sheet resistance,high transmittance, and high fl exibility. The eff ects of thermal treatment and mechanical compression on the structural,optical, and electrical properties of AgNW deposited by bar coating have been analyzed as a function of temperature andpressure. It was discovered that there is a critical thermal treatment temperature (T c ) that determined the abrupt change—decreasing, then rapidly increasing—in the sheet resistance of AgNW. When additional pressure was applied during thermaltreatment, T c was lowered. The cohesion between AgNW wires was improved by thermal treatment below T c , and furtherstrengthened when pressure was applied simultaneously with heat. However, when thermal treatment was performed aboveT c , the unique wire structure of AgNW collapsed. It has also been found that heat treatment and mechanical compressionimprove the fl exibility of AgNW.

Silver nanowire/carbon nanotube/cellulose hybrid papers for electrically conductive and electromagnetic interference shielding elements

Choi, Hyeong Yeol,Lee, Tae-Won,Lee, Sang-Eui,Lim, JaeDeok,Jeong, Young Gyu Elsevier Applied Science Publishers 2017 Composites science and technology Vol.150 No.-

<P><B>Abstract</B></P> <P>We report the microstructures, electrical conductivity, and electromagnetic interference (EMI) shielding effectiveness of a series of hybrid cellulose papers coated alternatively with silver nanowire (AgNW) and multi-walled carbon nanotube (MWCNT), which are fabricated by controlling the dip-coating sequence and cycle. SEM images and EDS data reveal that AgNWs and/or MWCNTs are sequentially coated on the surfaces of the cellulose papers with increasing the dip-coating cycle and the coating density of the particles decreases gradually in thickness direction of the papers. This result is supported by the anisotropic apparent electrical conductivity of AgNW/MWCNT/cellulose hybrid papers in in-plane and thickness directions. In addition, the apparent electrical conductivity of the hybrid papers in the in-plane direction increases significantly from 0.17–0.22 S/cm to 2.55–2.83 S/cm with increasing the coating cycle from 2 to 10, although it is higher for the hybrid cellulose papers with AgNW top-coating layers than the hybrid papers with MWCNT top-coating layers at the same coating cycle. This result indicates that a highly effective and conductive AgNW/MWCNT network is formed on the cellulose fibers in a layer-by-layer manner. For the hybrid papers with 2.55–2.83 S/cm, high EMI shielding effectiveness of ∼23.8 dB at 1 GHz is achieved.</P>

은 나노와이어 기반 하이브리드 이중층 압력 센서

이진영,신동균,김기은,서유석,박종운 한국반도체디스플레이기술학회 2017 반도체디스플레이기술학회지 Vol.16 No.3

We have fabricated flexible and stretchable pressure sensors using silver nanowires (AgNWs) and analyzed their electric responses. AgNWs are spray coated directly onto uncured polydimethylsiloxane (PDMS) such that AgNWs penetrate into the uncured PDMS, enhancing the adhesion properties of AgNWs. However, the single-layered AgNW sensor exhibits unstable electric response and low pressure sensitivity. To tackle it, we have coated a conductive polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) onto the AgNW layer. Such a hybrid bilayer sensor ensures a stable electric response because the over-coating layer of PEDOT:PSS effectively suppresses the protrusion of AgNWs from PDMS during release. To enhance the sensitivity further, we have also fabricated a stacked bilayer AgNW sensor. However, its electric response varies depending sensitively on the initial overlap pressure.

샌드위치 구조를 갖는 은 나노와이어 기반 고감도 저항성 압력 센서

이진영,김기은,신동균,박종운 한국반도체디스플레이기술학회 2018 반도체디스플레이기술학회지 Vol.17 No.2

Elastic resistive pressure sensor is fabricated by a direct spray coating of silver nanowires (AgNWs) on uncured polydimethylsiloxane (PDMS) and an additional coating of a conductive polymer, poly(3,4-ethylenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS). To improve the sensitive and stability, we have fabricated sandwich-structured AgNW/polymer sensor where two AgNW/polymer–coated PDMS films are laminated with the conducting surfaces contacted by pressure lamination. It shows a resistance decrease upon loading due to the formation of dense network of AgNWs. It is demonstrated that the sandwich-structured AgNW/polymer sensor exhibits very high sensitivity (2.59 kPa-1) and gauge factor (37.8) in the low pressure regime. It can also detect a subtle placement and removal of a weight as low as 3.4 mg, the corresponding pressure of which is about 5.4 Pa. It is shown that the protrusion of AgNWs from PDMS is suppressed substantially by the over-coated PEDOT:PSS layer, thereby reducing hysteresis and rendering the sensor more stable.

Electrically conductive polystyrene nanocomposites incorporated with aspect ratio‐controlled silver nanowires

Kim, Jung Mock,Jang, Keon‐,Soo,Lee, Seong Jae John Wiley Sons, Inc. 2019 Journal of applied polymer science Vol.136 No.36

<P><B>ABSTRACT</B></P><P>Polymer nanocomposites consisting of electrically conductive nanofillers with high aspect ratios are widely utilized for high‐performance applications such as sensors and electronics. Silver nanowires (AgNWs) synthesized through polyol reduction have been reported to show excellent electrical conductivity, hydrophilicity, and high aspect ratios. In this study, the influence of the aspect ratios of the AgNWs on the rheological and electrical properties of the fabricated polystyrene (PS)/AgNW nanocomposites was chiefly investigated. The nanocomposites were made by combining a dispersion of AgNWs with a suspension of PS particles, followed by freeze‐drying the PS/AgNW mixture harnessing the latex technology. Scanning electron microscopy, UV–Vis spectroscopy, and thermogravimetric analysis were performed on the nanocomposites to investigate the morphological, optical, and thermal properties, respectively; in addition, X‐ray photoelectron spectroscopy was performed to examine the hydrophilic polymer poly(vinylpyrrolidone)‐capped AgNW surfaces. The rheological behavior of the nanocomposites changed from liquid‐like to solid‐like after the addition of AgNWs with high aspect ratios. The electrical percolation threshold of the AgNWs in the nanocomposites was determined by the aspect ratio of the nanofiller rather than by its length. Thus, the various properties of the PS/AgNW nanocomposites could be tuned by tailoring the aspect ratios of the AgNWs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. <B>2019</B>, <I>136</I>, 47927.</P>

Influence of surface roughness on the efficiency of a flexible organic solar cell

Se Hoon Kim,Deuk Yong Lee,Young-Jei Oh 한양대학교 세라믹연구소 2020 Journal of Ceramic Processing Research Vol.21 No.1

Organic solar cells (OSCs) without an over-coating layer, consisting of a silver nanowire (AgNW) transparent electrode, apoly(3,4-ethylenedioxythiphene):poly (styrenesulfonate) (PEDOT:PSS) layer, a poly(3-hexylthiophene-2,5-diyl):the [6,6]-phenylC61 butyric acid methyl ester (P3HT:PCBM) active layer, a LiF/Al electron collecting, and a top electrode, were successfullyfabricated in order to investigate the effect of surface roughness on the efficiency of OSCs. The AgNW transparent electrodeon acryl resin coated polyethylene terephthalate (PET) film was prepared through the filtration/transfer method. Sheetresistance of 30 Ω-1 and surface roughness of 10.5 nm were detected. After coating the PEDOT:PSS hole transfer layer andthe P3HT:PCBM active layer at 1000 rpm on the AgNW/PET transparent electrode, the surface roughness was reduceddramatically. However, open circuit voltage, short circuit current density, fill factor, and power conversion efficiency decreasedas the coating speed was raised during the formation of the PEDOT:PSS layer and the P3HT:PCBM active layer due to thedeterioration of the surface roughness. The surface roughness was determined to be crucial for the output performance ofOSCs.

신축성있는 Ag 나노와이어 전극의 제조 및 전기변색 응용

이진영,한송이,나윤채,박종운,Lee, Jin-Young,Han, Song-Yi,Nah, Yoon-Chae,Park, Jongwoon 한국재료학회 2019 한국재료학회지 Vol.29 No.2

We report on stretchable electrochromic films of poly(3-hexylthiophene) (P3HT) fabricated on silver nanowire (AgNW) electrodes. AgNWs electrodes are prepared on polydimethylsiloxane (PDMS) substrates using a spray coater for stretchable electrochromic applications. On top of the AgNW electrode, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is introduced to ensure a stable resistance over the electrode under broad strain range by effectively suppressing the protrusion of AgNWs from PDMS. This bilayer electrode exhibits a high performance as a stretchable substrate in terms of sheet resistance increment by a factor of 1.6, tensile strain change to 40 %, and stretching cycles to 100 cycles. Furthermore, P3HT film spin-coated on the bilayer electrode shows a stable electrochromic coloration within an applied voltage, with a color contrast of 28.6 %, response time of 4-5 sec, and a coloration efficiency of $91.0cm^2/C$. These findings indicate that AgNWs/PEDOT:PSS bilayer on PDMS substrate electrode is highly suitable for transparent and stretchable electrochromic devices.