• 공업화학
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• 제27권5호
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• pp.512-515
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• 2016

새로운 viologen 유도체인 1,1'-bis(3,4-dihydroxybutyl)-[4,4'-bipyridine]-1,1'-diium bromide (V-Pr-2OH)을 합성하여 PTB7 : $PC_{71}BM$ Blend를 기반으로 하는 inverted polymer solar cells (iPSCs)에 cathode buffer layer로 적용하였다. V-Pr-2OH이 cathode buffer layer로 적용된 PSCs (ITO/V-Pr-2OH/PTB7 : $PC_{71}BM/MoO_3/Ag$)의 power conversion efficiency (PCE)는 7.28%이었다. V-Pr-2OH이 없는 iPSCs (ITO/ZnO/PTB7 : $PC_{71}BM/MoO_3/Ag$)의 PCE (7.41%)에 상응하는 값이다. 그러므로 본 연구에서는 높은 열처리 공정이 필요한 ZnO가 배제된, 즉 높은 온도의 열처리 없이도 제작 가능한 PSC에 대한 가능성을 보여주고 있다.

• Journal of Information Display
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• 제8권3호
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• pp.5-10
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• 2007

Twin target sputtering (TTS) system with a configuration of vertically parallel facing Al targets and a substrate holder perpendicular to the Al target plane has been designed to realize a direct Al cathode sputtering on organic light emitting diodes (OLEDs). The TTS system has a linear twin target gun with ladder type magnet array for effective and uniform confinement of high density plasma. It is shown that OLEDs with Al cathode deposited by the TTS show a relatvely lower leakage current density $({\sim}1{\times}10^{-5}mA/cm^2)$ at reverse bias of -6V, compared to that ($1{\times}10^{-2}{\sim}10^{-3}$ $mA/cm^2$ at -6V) of OLEDs with Al cathodes grown by conventional DC magnetron sputtering. In addition, it was found that Al cathode films prepared by TTS were amorphous structure with nanocrystallines due to low substrate temperature. This demonstrates that there is no plasma damage caused by the bombardment of energetic particles. This indicates that the TTS system with ladder type magnet array could be useful plasma damage free deposition technique for direct Al cathode sputtering on OLEDs or flexible OLEDs.

• 전기전자학회논문지
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• 제13권1호
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• pp.87-93
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• 2009

본 논문에서는 높은 홀딩 전압을 갖는 사이리스터(SCR; Silicon Controlled Rectifier)구조에 기반 한 새로운 구조의 ESD(Electro-Static Discharge) 보호 소자를 제안하였다. 홀딩전압은 애노드단을 감싸고 있는 n-well에 p+ 캐소드를 확장시키고, 캐소드단을 n-well로 추가함으로써 홀딩전압을 증가시킬 수 있다. 제안된 소자는 높은 홀딩전압 특성으로 높은 래치업 면역성을 갖는다. 본 연구에서 제안된 소자의 전기적 특성, 온도특성, ESD 감내특성을 확인하기 위하여 TCAD 시뮬레이션 툴을 이용하여 시뮬레이션을 수행하였다. 시뮬레이션 결과 제안된 소자는 10.5V의 트리거 전압과 3.6V의 홀딩전압을 갖는다. 그리고 추가적인 n-well과 확장된 p+의 사이즈 변화로 4V이상의 홀딩전압을 갖는 것을 확인하였다.

• 한국표면공학회지
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• 제49권3호
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• pp.316-321
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• 2016

To study emission characteristics for dual-emission tandem organic light emitting display (OLED), we fabricated blue fluorescent OLED according to thickness variation of $MoO_x$ as charge generation layer and Al as cathode. The bottom emission characteristics of OLED with $MoO_x$ 2, 3, 5 nm thickness showed threshold voltage of 9, 7, 9 V, maximum current emission efficiency of 19.32, 23.18, 15.44 cd/A and luminance of $1,000cd/m^2$ at applied voltage of 17.6, 13.2, 16.5 V, respectively. The top emission characteristics of OLED with $MoO_x$ 2, 3, 5 nm thickness indicated threshold voltage of 13, 10, 13 V, maximum current emission efficiency of 0.17, 0.23, 0.16 cd/A and luminance of $50cd/m^2$ at applied voltage of 22.6, 16.5, 20.1 V, respectively. In case of thicker or thinner than $MoO_x$ of 3 nm, the emission characteristics were decreased because of mismatching of electron and hole in emission layer. The bottom emission characteristics of OLED with Al 15, 20, 25 nm thickness showed threshold voltage of 8, 8, 7 V, maximum current emission efficiency of 18.42, 22.98, 23.18 cd/A and luminance of $1000cd/m^2$ at applied voltage of 16.2, 13.9, 13.2 V, respectively. The reduction of threshold voltage and increase of maximum current emission efficiency are caused by the increase of current injection according to increase of Al cathode thickness. The top emission characteristics of OLED with Al 15, 20, 25 nm thickness indicated threshold voltage of 7, 7, 8 V, maximum emission luminance of 371, 211, $170cd/m^2$, respectively. The top emission OLED of Al cathode with 15 nm thickness showed maximum luminance and it decreased at thickness of 20 nm. These phenomena are caused by the decrease of intensity of emitted light by reduction of optical transmittance according to increase of Al cathode thickness.

• 전기화학회지
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• 제19권1호
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• pp.1-8
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• 2016

층상구조 삼성분계 $LiNi_{1-x-y}Co_xMn_yO_2$ 양극활물질을 4.3 V 이상 고전압으로 충전시키면 용량 증가를 기대할 수 있으나 기존 전해액의 산화안정성이 낮아 고전압 성능 구현에 제한이 있다. 본 연구에서는 설폰계 전해액 첨가제인 dimethyl sulfone (DMS), diethyl sulfone (DES), ethyl methyl sulfone (EMS)을 사용하여 $LiNi_{0.5}Co_{0.2}Mn_{0.3}O_2$ 양극의 고전압 특성을 향상시키고자 한다. 본 논문은 다양한 선형 sulfone계 첨가제가 포함된 전해액에서 3.0-4.6 V 전압범위에서 양극의 충방전 특성과 양극-전해액간 계면거동과 표면층 분석에 대한 내용으로 이루어져 있다. 특히 Dimethyl sulfone (DMS) 첨가제 사용시, 50 사이클 중 $198-173mAhg^{-1}$의 방전 용량과 87%의 용량유지율을 보여 기존 전해액 대비 상당히 향상된 충방전 안정성을 보였다. 표면조성 분광분석 결과, DMS 첨가제 사용시 양극에 안정한 표면보호층이 형성되고 금속 용출이 억제되어 고전압 충방전 특성이 향상되었음 알 수 있었다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권6호
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• pp.601-607
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• 2015

A set of novel silicon controlled rectifier (SCR) devices' characteristics have been analyzed and verified under the electrostatic discharge (ESD) stress. A ring-shaped diffusion was added to their anode or cathode in order to improve the holding voltage (Vh) of SCR structure by creating new current discharging path and decreasing the emitter injection efficiency (${\gamma}$) of parasitic Bipolar Junction Transistor (BJT). ESD current density distribution imitated by 2-dimensional (2D) TCAD simulation demonstrated that an additional current path exists in the proposed SCR. All the related devices were investigated and characterized based on transmission line pulse (TLP) test system in a standard $0.5-{\mu}m$ 24 V CDMOS process. The proposed SCR devices with ring-shaped anode (RASCR) and ring-shaped cathode (RCSCR) own higher Vh than that of Simple SCR (S_SCR). Especially, the Vh of RCSCR has been raised above 33 V. What's more, their holding current is kept over 800 mA, which makes it possible to design power clamp with SCR structure for on chip ESD protection and keep the protected chip away from latch-up risk.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.359-362
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• 2000

The purpose of this study is to research and develop graphene composite for lithium polymer battery. VO(graphene) composite is one of the promising material as a electrode active material for lithium polymer battery(LPB). We investigated AC impedance response and charge/discharge cycling of VO(graphene)/SPE/Li cells. The first discharge capacity of VO(graphene) cathode with 50wt.% V$_2$O$\sub$5/ was 150mAh/g, while that of VO(graphene) cathode with 85wt.% V$_2$O$\sub$5/ was 248mAh/g. The Ah efficiency was above 98% after the 2nd cycle. The discharge capacity of VO(graphene) anode with 3wt.% V$_2$O$\sub$5/ was 718 and 266mAh/g at cycle 1 and 10 at room temperature, respectively. The VO(graphene) anode with 3wt.% V$_2$O$\sub$5/ in PVDF-PAN-PC-EC-LiC1O$_4$ electrolyte showed good capacity with cycling.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2000년도 춘계총회 및 학술발표회
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• pp.41-41
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• 2000

• 한국재료학회지
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• 제29권9호
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• pp.519-524
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• 2019

Spherical $Li_3V_2(PO_4)_3$ (LVP) and carbon-coated LVP with a monoclinic phase for the cathode materials are synthesized by a hydrothermal method using $N_2H_4$ as the reducing agent and saccharose as the carbon source. The results show that single phase monoclinic LVP without impurity phases such as $LiV(P_2O_7)$, $Li(VO)(PO_4)$ and $Li_3(PO_4)$ can be obtained after calcination at $800^{\circ}C$ for 4 h. SEM and TEM images show that the particle sizes are $0.5{\sim}2{\mu}m$ and the thickness of the amorphous carbon layer is approximately 3~4 nm. CV curves for the test cell are recorded in the potential ranges of 3.0~4.3 V and 3.0~4.8 V at a scan rate of $0.01mV\;s^{-1}$ and at room temperature. At potentials between 3.0 and 4.8 V, the third $Li^+$ ions from the carbon-coated LVP can be completely extracted, at voltages close to 4.51 V. The carbon-coated LVP exhibits an initial specific discharge capacity of $118mAh\;g^{-1}$ in the voltage region of 3.0 to 4.3 V at a current rate of 0.2 C. The results indicate that the reducing agent and carbon source can affect the crystal structure and electrochemical properties of the cathode materials.

• Journal of Korean Vacuum Science & Technology
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• 제5권1호
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• pp.19-24
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• 2001

The paper represents the results of the development and the test of "cold cathode" ion source model with 5 cm aperture where the glow discharge is utilized for generation of electrons in the cathode of the ion source. The results of probe measurements of the ion source are represented. The integral parameters such as electron energy distribution function(EEDF), electron density and mean electron energy, discharge voltage-current characteristics, and distribution of ion beam were studied.