Highly Durable and Flexible Transparent Electrode for Flexible Optoelectronic Applications

Jin, Sang Woo,Lee, Yong Hui,Yeom, Kyung Mun,Yun, Junyeong,Park, Heun,Jeong, Yu Ra,Hong, Soo Yeong,Lee, Geumbee,Oh, Seung Yun,Lee, Jin Ho,Noh, Jun Hong,Ha, Jeong Sook American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.36

<P>A highly-durable, highly-flexible transparent electrode (FTE) is developed by applying a composite made of a thin metal grid and a doped conducting polymer onto a colorless polyimide-coated NOA63 substrate. The proposed FTE exhibits a transparency of 90.7% at 550 nm including the substrate and a sheet resistance of 30.3 Ω/sq and can withstand both moderately high-temperature annealing (∼180 °C) and acidic solution (70 °C, pH 0.3) processes without performance degradation. The fabricated FTE yielded good mechanical stability under 10 000 cycles of bending deformations at a bending radius less than 1 mm without degradation of electrical conductivity. The high durability of the proposed FTE allows for the fabrication of flexible energy harvesting devices requiring harsh conditions, such as highly flexible perovskite solar cells (FPSCs) with a steady-state power conversion efficiency (PCE) of 12.7%. Notably, 93% of the original PCE is maintained after 2000 bending cycles at an extremely small bending radius of 1.5 mm. The FPSCs installed on curved surfaces of commercial devices drive them under various environments. The applicability of the proposed FTE is further confirmed via the fabrication of a flexible perovskite light-emitting diode. The proposed FTE demonstrates great potential for applications in the field of flexible optoelectronic devices.</P> [FIG OMISSION]</BR>

The level of decoy epitope in PCV2 vaccine affects the neutralizing activity of sera in the immunized animals

Jin, Junyeong,Park, Changhoon,Cho, Sun-Hee,Chung, Junho Elsevier 2018 Biochemical and biophysical research communication Vol.496 No.3

<P><B>Abstract</B></P> <P>Viral pathogens have evolved a wide range of tactics to evade host immune responses and thus propagate effectively. One efficient tactic is to divert host immune responses toward an immunodominant decoy epitope and to induce non-neutralizing antibodies toward this epitope. Therefore, it is expected that the amount of decoy epitope in a subunit vaccine can affect the level of neutralizing antibody in an immunized animal. In this study, we tested this hypothesis by generating an antibody specific to the decoy epitope on the capsid protein of porcine circovirus type 2 (PCV2). Using this antibody, we found that two commercial vaccines contained statistically different amounts of the decoy epitope. The vaccine with lower levels of decoy epitope induced a significantly higher level of neutralizing antibody after immunization. This antibody can be used as an analytical tool to monitor the quality of a vaccine from batch to batch.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We generated a novel antibody specific to an immunodominant decoy epitope of PCV2. </LI> <LI> Using this novel antibody, we measured levels of decoy epitope in PCV2 vaccine. </LI> <LI> Decoy epitope in PCV2 vaccine affected the neutralizing antibody titer induction. </LI> </UL> </P>

Deep blue energy harvest photovoltaic switching by heptazole-based organic Schottky diode circuits

Lee, Junyeong,Raza, Syed Raza Ali,Jeon, Pyo Jin,Kim, Jin Sung,Im, Seongil Nature Publishing Group 2016 NPG Asia Materials Vol.8 No.-

<P>We report novel photovoltaic (PV) switching based on the low exciton-binding energy property of an organic heptazole (C26H16N2) thin film after fabrication of an heptazole-based Schottky diode. The Schottky diode cell displayed an instantaneous voltage of 0.3 V as an open circuit voltage (V-OC) owing to the work function difference between the Schottky and ohmic electrode under deep blue illumination. Four tandem diode cells therefore produced similar to 1.2 V. As a PV diode circuit can be formed using an even number of diodes, a photo-excited charge accumulation takes place, generating V-OC in the central electrode of the tandem diode array by illuminating one half of the array. An electron-hole recombination then also takes place in that electrode by illuminating the other half, making the V-OC decrease to 0 V. Utilizing this charge accumulation and recombination under deep blue illumination, we successfully demonstrated quite fast PV optical switching, logic gating and, ultimately, the gate switching of an organic field-effect transistor. We therefore concluded that our self-powered PV-induced switching was novel and promising enough to open a new door for energy harvest-related device applications in organics.</P>

Simultaneous Protection of Organic p- and n-Channels in Complementary Inverter from Aging and Bias-Stress by DNA-Base Guanine/Al₂O₃ Double Layer

Lee, Junyeong,Hwang, Hyuncheol,Min, Sung-Wook,Shin, Jae Min,Kim, Jin Sung,Jeon, Pyo Jin,Lee, Hee Sung,Im, Seongil American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.3

<P>Although organic field-effect transistors (OFETs) have various advantages of lightweight, low-cost, mechanical flexibility, and nowadays even higher mobility than amorphous Si-based FET, stability issue under bias and ambient condition critically hinder its practical application. One of the most detrimental effects on organic layer comes from penetrated atmospheric species such as oxygen and water. To solve such degradation problems, several molecular engineering tactics are introduced: forming a kinetic barrier, lowering the level of molecule orbitals, and increasing the band gap. However, direct passivation of organic channels, the most promising strategy, has not been reported as often as other methods. Here, we resolved the ambient stability issues of p-type (heptazole)/or n-type (PTCDI-C13) OFETs and their bias-stability issues at once, using DNA-base small molecule guanine (C<SUB>5</SUB>H<SUB>5</SUB>N<SUB>5</SUB>O)/Al<SUB>2</SUB>O<SUB>3</SUB> bilayer. The guanine protects the organic channels as buffer/and H getter layer between the channels and capping Al<SUB>2</SUB>O<SUB>3</SUB>, whereas the oxide capping resists ambient molecules. As a result, both p-type and n-type OFETs are simultaneously protected from gate-bias stress and 30 days-long ambient aging, finally demonstrating a highly stable, high-gain complementary-type logic inverter.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-3/am507354p/production/images/medium/am-2014-07354p_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am507354p'>ACS Electronic Supporting Info</A></P>

Consideration of parasitic elements in magneto-impedance

Junyeong Choi,Geun-Hee Lee,Kab-Jin Kim 한국자기학회 2024 한국자기학회 학술연구발표회 논문개요집 Vol.34 No.1

Modulating Lactam Riboswitch for High-throughput Screening and Selection Efficiency

Junyeong SUNG,Sungyoen JANG,Sungho JANG,Dae-Kyun IM,Taek Jin KANG,Min-Kyu OH,Gyoo Yeol JUNG 한국생물공학회 2020 한국생물공학회 학술대회 Vol.2020 No.10

Study on COS Adsorption Behavior and Their Mechanism Using Activated Carbon Modified with KOH

Junyeong Kim(김준영),No-Kuk Park(박노국),Seung Jong Lee(이승종),Jin Pyo Hong(홍진표),Misook Kang(강미숙) 한국에너지기후변화학회 2018 한국에너지기후변화학회 학술대회 Vol.2018 No.5

Stretchable array of high-performance micro-supercapacitors charged with solar cells for wireless powering of an integrated strain sensor

Yun, Junyeong,Song, Changhoon,Lee, Hanchan,Park, Heun,Jeong, Yu Ra,Kim, Jung Wook,Jin, Sang Woo,Oh, Seung Yun,Sun, Lianfang,Zi, Goangseup,Ha, Jeong Sook Elsevier 2018 Nano energy Vol.49 No.-

<P><B>Abstract</B></P> <P>The aim of this paper is to report on the fabrication of a stretchable array of high-performance solid-state micro-supercapacitors (MSCs), which can be charged with integrated, commercial Si-based solar cells (SCs). This would facilitate the powering of an integrated strain sensor. The planar MSCs comprised electrodes of potentiostatically deposited polypyrrole, on spray-coated multi-walled carbon nanotube film, and a gel-type electrolyte of LiCl/polyvinyl alcohol with a redox additive of 1-methyl-3-propylimidazolium iodide. The fabricated MSC achieved an areal capacitance of 5.17 mF cm<SUP>−2</SUP>. After 5000 charge/discharge cycles, the MSC retained 80% of their initial capacitance. A strain sensor was fabricated utilizing a composite film of fragmentized graphene foam and polydimethylsiloxane. Such fabricated twelve parallel connected MSCs, a strain sensor, and SCs were integrated on a single deformable polymer substrate with embedded stiff platforms of negative epoxy series resist (SU-8) via long serpentine interconnections of polyimide encapsulated Ti/Pt metal film for mechanical stability under stretching. After 1000 repetitive biaxial stretching/releasing cycles by 30%, no noticeable change was observed in the charge/discharge behavior of the MSC array. Furthermore, both the photo-charge/discharge characteristics and electrochemical performance remained stable. When the whole integrated system was attached to the wrist, the integrated strain sensor could detect both externally applied strain and the arterial pulse using the energy stored in the MSCs from the SCs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We fabricate a stretchable array of micro-supercapacitors charged by solar cells for wireless powering of the integrated strain sensor. </LI> <LI> Serpentine interconnections with the embedded stiff SU-8 platform enable stable performance under stretching deformation. </LI> <LI> Strain sensor detects pulse signal of the radial artery and bending motion of the wrist. </LI> <LI> The sensor is operated for 100 s with energy supplied by the integrated array. </LI> <LI> Under repeated biaxial stretching, the stretchable array retains stable performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

DNA-Base Guanine as Hydrogen Getter and Charge-Trapping Layer Embedded in Oxide Dielectrics for Inorganic and Organic Field-Effect Transistors

Lee, Junyeong,Park, Ji Hoon,Lee, Young Tack,Jeon, Pyo Jin,Lee, Hee Sung,Nam, Seung Hee,Yi, Yeonjin,Lee, Younjoo,Im, Seongil American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.7

<P>DNA-base small molecules of guanine, cytosine, adenine, and thymine construct the DNA double helix structure with hydrogen bonding, and they possess such a variety of intrinsic benefits as natural plentitude, biodegradability, biofunctionality, low cost, and low toxicity. On the basis of these advantages, here, we report on unprecedented useful applications of guanine layer as hydrogen getter and charge trapping layer when it is embedded into a dielectric oxide of n-channel inorganic InGaZnO and p-channel organic heptazole field effect transistors (FETs). The embedded guanine layer much improved the gate stability of inorganic FETs gettering many hydrogen atoms in the gate dielectric layer of FET, and it also played as charge trapping layer to which the voltage pulse-driven charges might be injected from channel, resulting in a threshold voltage (<I>V</I><SUB>th</SUB>) shift of FETs. Such shift state is very ambient-stable and almost irrevocable even under a high electric-field at room temperature. So, Boolean logics are nicely demonstrated by using our FETs with the guanine-embedded dielectric. The original <I>V</I><SUB>th</SUB> is recovered only under high energy blue photons by opposite voltage pulse (charge-ejection), which indicates that our device is also applicable to nonvolatile photo memory.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-7/am405998d/production/images/medium/am-2013-05998d_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am405998d'>ACS Electronic Supporting Info</A></P>

Adsorption/desorption behavior of carbonyl sulfide gas on Scheelite type MWO₄ adsorbent

Kim, Junyeong,Do, Jeong Yeon,Park, No-Kuk,Hong, Jin-Pyo,Kang, Misook Elsevier 2018 Separation and purification technology Vol.207 No.-

<P><B>Abstract</B></P> <P>This study focused the metal oxide adsorbents to remove small amounts of carbonyl sulfide (OCS) during coal gasification, which was a preliminary step for Integrated Gasification Fuel Cell operation. This study attempted to improve the function of the adsorbent by introducing two kinds of metal species, alkaline earth metals (M=Ca, Mg, Sr, and Ba) and W, fabricated as a Scheelite-typed MWO<SUB>4</SUB> crystal. COS gases were broken down into CO and S segments on the surface of the adsorbents, and were then adsorbed onto the alkaline and W sides. The COS removals decreased in the order of CaWO<SUB>4</SUB> > SrWO<SUB>4</SUB> > BaWO<SUB>4</SUB> > MgWO<SUB>4</SUB> > WO<SUB>3</SUB>. When the adsorbent had an ideal basicity, the CO and S adsorbed well on the surface of the adsorbent, resulting in easy breakage of the CO and S bonds. But, this study indicated that it was more influential to optimally align the adsorbate and adsorbent surface. For the Scheelite-type CaWO<SUB>4</SUB> adsorbent, the distance of the adsorbing active site, CaOW, was similar in size to the COS adsorbate molecule, suggested a good alignment approaching the <I>C</I>-axis of the adsorbent. Moreover, an important result in this study determined by mass spectroscopy was that when COS adsorption was saturated on the MWO<SUB>4</SUB> surface, the adsorbed COS gases could desorb from the MWO<SUB>4</SUB> surface with CO<SUB>2</SUB>, SO<SUB>2</SUB>, CS, and CS<SUB>2</SUB> gases, which are more toxic than COS. This can be considered to other secondary environmental pollutants.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Scheelite-typed MWO<SUB>4</SUB> crystals fabricated by alkaline earth metals and W. </LI> <LI> COS molecules were broken down into CO and S segments on adsorbents. </LI> <LI> COS removal ability was the best on CaWO<SUB>4</SUB> adsorbent. </LI> <LI> On CaWO<SUB>4</SUB>, the COS adsorbate had a good alignment approaches forward the <I>C</I>-axis of the adsorbent. </LI> <LI> COS gases were desorbed as CO<SUB>2</SUB>, SO<SUB>2</SUB>, CS, and CS<SUB>2</SUB> gases. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>