• 한국전기전자재료학회논문지
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• 제18권12호
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• pp.1143-1147
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• 2005

In this study, we report an improved efficiency of Organic light emitting diodes(OLEDs), using $UV/O_3$ treated anode and different cathode. We investigated the efficiency of OLEDs by $UV/O_3$ treatment of ITO surface. We Performed $UV/O_3$ treatment and found that $UV/O_3$ treatment enhanced the performance of OLEDs. The fundamental structure of the OLEDs was ITO $anode/{\alpha}-NPD/Alq_3/Al$ or Li:Al cathode. The Li:Al can improve the OLEDs efficiency dramatically in cathode because it has lower work function than Al. Current-voltage, Luminance-voltage characteristics and luminance efficiency were measured at room temperature.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.74-75
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• 2007

We report on the characteristics of organic light-emitting diodes with Al cathode deposited by specially designed twin target sputter(TTS) system. It was found that the Al cathode films grown by TTS system were amorphous structure with nanocrystallines due to low substrate temperature during sputtering process. Effective confinement of high-density plasma between two Al targets lead to low temperature sputtering process on organic layer. Moreover, organic light-emitting diodes with Al cathode deposited by TTS system exhibited low leakage current density of $4{\times}10^{-6}\;mA/cm2$ at -6 V indicating plasma damage due to bombardment of energetic particles such as ions and $\gamma$-electrons was effectively restricted in the ITS system. Sputtering method using ITS system is expected to be applied in organic electronics and flexible displays due to its low temperature and plasma damage free deposition process.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.655-658
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• 2007

Characteristics of Al cathode films deposited by using specially designed twin target sputter (TTS) system were investigated. It was found that Al cathode films prepared by TTS were amorphous structure with nanocrystallines due to low substrate temperature and OLEDs fabricated using TTS system have low leakage current density at reverse bias because of effective confinement of energetic particles during sputtering process.

• Korean Chemical Engineering Research
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• 제59권1호
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• pp.42-48
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• 2021

본 연구에서는 LiNi0.85Co0.15O2의 전기화학적 특성과 열적 안정성을 향상시키기 위하여 LiNi0.85Co0.15O2에 이종원소인 Zn와 Al을 함께 첨가하여 고상법으로 합성하였다. 물질의 결정 구조, 크기 및 표면 상태는 XRD, SEM을 이용하여 분석하였고 전기화학적 특성은 충방전기를 이용하여 CV(cyclic voltammetry), 초기 충·방전 프로파일, 출력 특성, 수명 특성 등을 측정하였다. Al-O의 강한 결합에너지는 양극활물질의 구조적 안정성을 향상시켰으며, Li+와 Ni2+의 양이온 혼합을 막아 전기화학적 특성 또한 향상되었다. Zn의 큰 이온반경은 양극활물질의 격자상수를 증가시켜 단위 셀의 부피가 확장되었다. Zn와 Al을 0.025몰씩 첨가한 물질의 경우, 0.5 C-rate의 전류밀도에서 100 사이클 동안 80%의 용량 유지율을 보여주었으며 이 결과는 NC 양극활물질보다 12% 높은 수치이다. 또한, 5 C-rate에서의 방전용량은 104 mAh/g으로 기존의 NC 양극활물질보다 36 mAh/g 높은 수치를 보였다. Zn과 Al이 0.025몰씩 첨가된 NC 양극활물질은 출력 특성, 수명 특성에서 우수한 특성을 보여주었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1266-1267
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• 2011

We studied the influence of cathode material on the stability of organic phtovoltaics (OPVs). OPVs with LiF/Al and Ag/Ca/Ag cathode were fabricated and the stability were evaluated. The sample with LiF/Al cathode showed efficiency degradation from 2.42% to 2.04% during 50 days. On the other hand, the sample with Ag/Ca/Ag cathode showed more steeper efficiency degradation from 2.38% to 0.80% during 50 days. The different of degradation can be attributed to a larger increase of series resistance ($R_s$) in Ag/Ca/Ag cathode sample.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.345-346
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• 2008

We have studied an emission spectra of top-emssion organic light-emitting diodes(TEOLED) due to a change of cathode and organic layer thickness. Device structure is Al(100nm)/TPD(xnm)/$Alq_3$(ynm)/LiF(0.5nm)/cathode. And two different types of cathode were used; one is LiF(0.5nm)/Al(25nm) and the other is LiF(0.5nm)/Al(2nm)/Ag(30nm). While a thickness of hole-transport layer of TPD was varied from 35 to 65nm, an emissive layer thickness of $Alq_3$ was varied from 50 to 100nm for two devices. A ratio of those two layer was kept to be about 2:3. Al and Al/Ag double layer cathode devices show that the emission spectra were changed from 490nm to 560nm and from 490nm to 560nm, respectively, when the total organic layer increase. Full width at half maximum was changed from 67nm to 49nm and from 90nm to 35nm as the organic layer thickness increases. All devices show that view angle dependent emission spectra show a blue shift. Blue shift is strong when the organic layer thickness is more than 140nm. Devece with Al/Ag double layer cathode is more vivid.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1038-1041
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• 2002

We have investigated the effects of cathode in organic light-emitting diodes of ITO/TPD/$Alq_3$/Cathodes(Al, LiF/Al, Ca/Al, and LiAl) by measuring current-voltage-luminance characteristics. The device with cathodes other than Al cathode shows the efficiency by an oder of one compared with Al cathode only. This improvement is due to a reduction of barrier height in cathode side.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 춘계학술대회 논문집 센서 박막재료연구회 및 광주 전남지부
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• pp.42-44
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• 2008

In this study, we report an electrical properties of green OLEO, using the changed thickness of Al Layer. We investigated the electrical properties of OLEOs by IVL and optical properties by EL spectrum. The fundamental structure of green OLEOs was ITO anode/TPD($400{\AA}$)/$Alq_3(600{\AA})$)/LiF($10{\AA}$)/Al($200{\sim}600{\AA}$) cathode. The threshold voltage was low value according to the more thin Al layer. The luminance was increased by decreased cathode layer. The threshold voltage was 12V and wavelength was 530nm at $200{\AA}$ cathode.

• 한국응용과학기술학회지
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• 제21권4호
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• pp.274-278
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• 2004

In this study, hetero-electrode structures have been fabricated to increase luminescence efficiency. The presence of a thin layer of Sn or Ag at the organic-aluminum interface enhanced both electron injection efficiency and electroluminescence when compared to OLEDs using homogeneous electrode. In this paper, the effect of the cathode using Sn/Al hetero electrode structure is observed. Electric properties of the OLED using Sn/Al hetero cathode are improved in comparison of only Al cathode. The hetero-electrode existing different energy level induces the advanced structure of OLED can accumulate electron density. The luminescence efficiency of OLED with Sn/Al of Ag/Al cathode is higher because of their higher electron injection efficiency. And, the turn on voltage of the OLED device using Sn thin layer is lowest as about 10 V.

• 전기화학회지
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• 제13권4호
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• pp.246-250
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• 2010

In this study, nano-crystallized $Al_2O_3$ was coated on the surface of $LiFePO_4$ powders via a novel dry coating method. The influence of coated $LiFePO_4$ upon electrochemical behavior was discussed. Surface morphology characterization was achieved by transmission electron microscopy (TEM), clearly showing nano-crystallized $Al_2O_3$ on $LiFePO_4$ surfaces. Furthermore, it revealed that the $Al_2O_3$-coated $LiFePO_4$ cathode exhibited a distinct surface morphology. It was also found that the $Al_2O_3$ coating reduces capacity fading especially at high charge/discharge rates. Results from the cyclic voltammogram measurements (2.5-4.2 V) showed a significant decrease in both interfacial resistance and cathode polarization. This behavior implies that $Al_2O_3$ can prevent structural change of $LiFePO_4$ or reaction with the electrolyte on cycling. In addition, the $Al_2O_3$ coated $LiFePO_4$ compound showed highly improved area-specific impedance (ASI), an important measure of battery performance. From the correlation between these characteristics of bare and coated $LiFePO_4$, the role of $Al_2O_3$ coating played on the electrochemical performance of $LiFePO_4$ was probed.