• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.277-278
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• 2009

We have studied an angular dependence of emission pattern of top-emssion organic light-emitting diodes (TEOLED). Device structure is Al(100nm)/TPD(40nm)/$Alq_3$(60nm)/LiF(0.5nm)/Al(2nm)/Ag(30nm). N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine (TPD) and tris-(8-hydroxyquinoline) aluminium ($Alq_3$)were used as a hole transport layer and emission layer, respectively. Organic layers and cathode were thermally evaporated at $2\times10^{-5}$torr. The evaporation rate of the organic material was maintained to be $1.5\sim2.0{\AA}/s$, and that of metal layer to be $0.5\sim5{\AA}/s$. A transmittance of a cathode electrode(Al/Ag) in visible region is about 25~30%. In order to measure view-angle dependent intensity, electroluminenscence spectra of the device at each angle were integrated. Angle dependent emission spectra of the device do not show blue shift. Emission intensity of the device that the going straight characteristic is stronger the bottom-emission organic light-emitting diodes is shown.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.299-300
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• 2009

We have studied an organic layer and semitransparent Al cathode thickness dependent optical properties for top-emission organic light-emitting diodes. Device structure is ITO(170nm)/TPD(xnm)/$Alq_3$(ynm)/LiF(0.5nm)/Al(100nm) and Al(100nm)/TPD(xnm)/$Alq_3$(ynm)/LiF(0.5nm)/Al(25nm). While a thickness of total, organic layer was varied from 85nm to 165nm, a ratio of those two layers was kept to be about 2:3. Then it was compared with that of bottom devices. And a thickness of semitransparent Al cathode was varied from 20nm to 30nm for the device with an organic layer thickness of 140nm. We were able to control the emission spectra from the top-emission organic light-emitting diodes.

• 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.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.990-993
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• 2006

We fabricated top emission organic light emitting diode (TEOLED) with transparent metal cathode Barium and Silver bilayer. Very thin Ba/Ag bilayer was deposited on the organic layer by thermal evaporation. This cathode shows high transmittance over 70% in visible range. And the device with a Ba-Ag has a low turn on voltage and good electrical properties.

• 대한토목학회논문집
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• 제33권4호
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• pp.1675-1682
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• 2013

지구온난화(Global Warming) 문제를 해결하기 위해서는 이산화탄소 배출량을 줄여야 한다. 우리나라는 1인당 이산화탄소 배출량이 세계 Top 수준이기 때문에 배출량을 줄이기 위한 노력을 더욱 적극적으로 할 필요가 있다. 이산화탄소 배출량을 줄이기 위한 노력은 다방면으로 이루어지고 있다. 그러나 $CO_2$ 를 줄이기 위해서는 그것의 배출특성을 알아야 한다. 건설장비의 이산화탄소 배출량을 측정하여 비교분석하는 것은 이러한 측면에서 중요하다. 현재 가장 많이 이용되고 있는 배출량 산정방법은 연료사용량 대비 배출계수를 이용하는 방법이다. 그러나 이 방법은 연료사용량에 비례하지 않는 요인을 반영하지 못하므로 신뢰성에 문제가 있다. 본 연구에서는 건설장비의 이산화탄소 배출량을 직접측정방식으로 산정하여 배출계수에 의한 방식과 비교분석하고 그 차이에 대한 원인을 분석하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.352-355
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• 2004

• 한국전기전자재료학회논문지
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• 제16권4호
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• pp.330-335
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• 2003

This paper reports the optimum structure of the vacuum packaged Porous poly-silicon Nano-Structured (PNS) emitter. The PNS layer was obtained by electrochemical etching process into polycrystalline silicon layer in a process controlled to anodizing condition. Current-voltage studies were carried out to optimize process condition of electron emission properties as a function of anodizing condition and top electrode thickness. Also, we measured in advance the electron emission properties as a function of substrate temperature because the vacuum packaged process was performed under the condition of high temperature ambient (430$^{\circ}C$). Auger Electron Spectrometer (AES) studies shows that Au as a top-electrode was diffused to PNS layer during temperature experiments. Thus, we optimized the thickness of top-electrode in order to make the vacuum package PNS emitter. As a result, the vacuum Packaged PNS emitter was successfully emitted by optimizing process.

• 반도체디스플레이기술학회지
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• 제21권1호
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• pp.71-74
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• 2022

For the process simplification in the fabrication of organic light emitting diode(OLED), top emission OLED (TEOLED) was fabricated without lithium fluoride(LiF) used as an electron injection layer (EIL). After co-deposition of Mg and Ag with a different process conditions, a cathode material adjacent to EIL was optimized when Mg and Ag have a ratio of 1:9 considering sheet resistance and transmittance. From the energy band diagram of TEOLED, band gap difference between Trisaluminium (Alq3) and Mg:Ag cathode show the difference of 0.4 eV according to the usage of LiF The fabricated TEOLED without LiF showed the improvement of 5.2 % and 2.7 % in the luminance and the current density comparing that with LiF. The results show there is no significant difference in OLED characteristics regardless of LIF layer in the TEOLED structures.

• 한국해양공학회지
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• 제13권3B호
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• pp.47-55
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• 1999

A study on swirl chamber for diesel engine is to realize lower fuel consumption and exhaust emission than the current marketing engines. Author formerly reported the performance characteristics of small IDI diesel engine with swirl chamber by changing the jet passage area and its angle, and the depth and shape of the piston top cavity. Following after the first report, in this paper, the characteristics of fuel consumption, soot emission, and exhaust gas temperature were examined and analyzed after dimension of jet passage area expanded to $70.1mm^2$ The results were that the optimum values of the jet passage area depending on the depth of the piston top cavity were different at each engine speeds and loads, and in accordance with application of engine running conditions they were able to be selected as optimum dimensions of each design parameters.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.543-544
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• 2008

In the fabrication of inverted top emission organic light emitting diodes (ITOLEDs), the organic layers are damaged by high-energy plasma sputtering process for transparent top anode. In this study, the plasma process induced damages on metal oxide hole injection layers (HILs) including $WO_3$, $MoO_3$, and $V_2O_5$ as buffer layer are examined. With the result of IV characteristic of hole-only devices, we propose that $MoO_3$ and $V_2O_5$ are stable materials against plasma sputtering process.