• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.897-900
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• 2003

Chemical vapor condensation (CVC) reactor was investigated for the deposition of Parylene-N thin films as the passivation layer for organic light emitting diodes (OLEDs). Several gas inlet manifold designs were tested to improve the deposition rate and its uniformity, and it was found that proper inlet design is crucial to get the desired film properties. Process characterization was also performed with the modified inlets to optimize the process variables.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2011년도 춘계학술대회 및 Fine pattern PCB 표면 처리 기술 워크샵
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• pp.123-124
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• 2011

Tris(8-quinolinolato)aluminum(III) (Alq3)와 Cathode 사이에 Ba o f 1nm를 삽입함으로써 OLED device의 성능이 향상되었다. 이 소자에 삽입된 Ba는 electron-injection barrier height를 낮추어서 전자주입에 영향을 주었다. 그러나 Ba 의 두께가 1nm이상일 경우에는 특성이 안 좋은 소자 성능을 보여줌을 알 수 있었다.

• 한국광학회지
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• 제26권3호
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• pp.139-146
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• 2015

본 논문에서는 유전체 다층 거울을 이용해 구성된 파브리-페롯 미소공진 구조가 유기발광다이오드(OLED)의 광효율에 미치는 영향을 유한차분 시간영역법과 광선추적법을 결합해 분석하였다. SiN과 $SiO_2$ 층을 교대로 쌓아 구성한 유전체 다층박막의 적용은 미소공진 효과를 강화시켜 OLED의 발광 스펙트럼의 협소화를 유도하였고 광추출효율도 수 % 증가하였다. 유전체 다층박막의 두께를 최적화함으로써 특정 파장에 대해 미소공진 효과를 일으킬 수 있었고 이는 OLED 발광색의 순도를 증가시키는데 활용될 수 있다. 광추출효율을 극대화하는 전자수송층의 최적 두께는 발광파장에 따라 달라졌는데, 이는 유기층 물질이 보이는 굴절률의 분산 때문인 것으로 생각된다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.41-43
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• 2004

Plasma polymerized para-xylene ($PP_PX$) deposited by plasma-enhanced chemical vapor deposition (PECVD) was used as the barrier layer on the polyethylene terephthalate (PET) substrate to improve lifetime of the flexible organic light-emitting diodes (FOLEDs). The $PP_PX$ barrier layer deposited on top of the PET substrate with plasma power of 30 W at deposition pressure of 0.2 torr showed transmittance spectra good enough to be applied in FOLED on PET substrates. FOLEDs with the $PP_PX$ barrier layer (barrier-FOLEDs) showed similar I-V and B-V characteristics to FOLEDs without the $PP_PX$ layer (control-FOLEDs). The lifetime of barrier-FOLED was two times longer than that of the control-FOLED. With $PP_PX$ passivation layers, lifetimes of both control and barrier-FOLEDs were improved by more than 4 times. These results show that PECVD deposited $PP_PX$ layers can be used as barrier layers for FOLEDs on plastic substrates as well as passivation layers for general OLEDs.

• Journal of Information Display
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• 제9권2호
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• pp.18-21
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• 2008

We report on white organic light-emitting diodes (WOLEDs) based on single white dopants, $Ir(pq)_2$($F_2$-ppy) and $Ir(F_2-ppy)_2$(pq), where $F_2$-ppy and pq are 2-(2,4-difluorophenyl) pyridine and 2-phenylquinoline, respectively. The similar phosphorescent lifetime of two ligands lead to luminescence emission in two ligands simultaneously. However, the emission color of the devices was reddish, because the energy was not transferred efficiently from the 4,4,N,N'-dicarbazolebiphenyl (CBP) to the $F_2$-ppy ligand, due to the small band gap of the CBP. Accordingly, we used 1,4-phenylenesis(triphenylsilane) (UGH2) with a large band gap, instead of CBP as the host material. As a result, it was possible to adjust the emission color by the host material. The luminous efficiency of the device with $Ir(F_2-ppy)_2$(pq) doped in UGH2 was about 11 cd/A at 0.06 cd/$m^2$.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1038-1041
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• 2006

We report low operating voltage and long lifetime organic light-emitting diodes (OLEDs) with a vanadium oxide $(V_2O_5)-doped$ N,N'-di(1-naphthyl)- N,N'-diphenylbenzidine $({\alpha}-NPD)$ layer between indium tin oxide and ${\alpha}-NPD$. At a luminance of $1000\;cd/m^2$, $V_2O_5$ doped ${\alpha}-NPD$ device shows a operation voltage of 5.1V, while the device without $V_2O_5$ shows 5.8V. The $V_2O_5$ doped $({\alpha}-NPD)$ device also shows a longer lifetime and smaller operation voltage variation over time. It is suggested that the improved device performance can be attributed to the higher hole-injection efficiency and stability of the $V_2O_5$ doped $({\alpha}-NPD)$ layer.

• 한국전기전자재료학회논문지
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• 제22권4호
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• pp.327-332
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• 2009

In the devices structure of ITO/N,N'-diphenyl-N,N' bis (3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) /tris (8-hydroxyquinoline)aluminum$(Alq_3)$electron-transport-layer(ETL)(2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline(BCP))/Al, we have studied the efficiency improvement of organic light-emitting diodes depending on the thickness variation of BCP using electron transport layer. The thickness of TPD and $Alq_3$ was manufactured 40 nm, 60 nm under a base pressure of $5{\times}10^{-6}$ Torr using at thermal evaporation, respectively. The TPD and $Alq_3$ layer were evaporated to be deposition rate of $2.5{\AA}/s$. And the BCP was evaporated to be a4 a deposition of $1.0{\AA}/s$. As the experimental results, we found that the luminous efficiency and the external quantum efficiency of the device is superior to others when thickness of BCP is 5 nm. Also, operating voltage is lowest. Compared to the ones from the devices without BCP layer, the luminous efficiency and the external quantum efficiency were improved by a factor of four hundred ninty and five hundred, respectively. And operating voltage is reduced to about 2 V.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.388-389
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• 2007

In this work, Organic Light Emitting Diodes using Aluminum-Oxynitride as a hole-injecting interfacial have been fabricated. This interfacial layer is inserted at the ITO/N,NV-diphenyl-N, NV-bis(3-methylphenyl)-1,1V-diphenyl-4,4V-diamine (TPD) interface. The brightness and efficiency of the device with the AION film is higher than that of the device without it. The enhancements are attributed to an improved balance of hole and electron injections due to the energy level realignment and the change in carrier tunneling probability by the interfacial layer.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 학술대회 및 기술세미나 논문집 디스플레이 광소자
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• pp.81-82
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• 2006

Doping is a well-known method for improving electroluminescent (EL) efficiency of organic light emitting diodes. In our study, doping with 2 materials simultaneously, we could achieve improved EL efficiency. The emission layer was tris-(8-hydroxyquinoline)aluminum, and the 2 dopants were N,N'-dimethyl-quinacridone (DMQA) and 10-(2-Benzothiazolyl)-2, 3, 6, 7-tetrahydro-1,1,7,7,-tetramethyl 1-1H, 5H, 11H-[1] benzopyrano [6,7,8-ij]quinolizin-11-one (C-545T). The EL intensity of co-doped device was nearly flat, it shows that co-doping technique could be a effective way to improve the EL efficiency. EL efficiency of Single-doped device based on DMQA and C-S45T were ~6.47Cd/A and ~7.45Cd/A, respectively. Co-doped device showed higher EL efficiency of ~8.30Cd/A.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.955-962
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• 2005

Power efficiency, lifetime and stable manufacturing processes are the crucial parameters for the success of organic light emitting diodes (OLEDs) in display and lighting applications. Highest power efficiencies of PIN-OLEDs for all principal colours and for bottom and top emission OLED structures have been demonstrated. The PIN structure, which means the incorporation of intentionally doped charge carrier transport layer in a suitable OLED layer setup, lowers the operating voltage to achieve highest power efficiencies. Up to now the n-doping of the electron transport layer has been done by alkali metal co-deposition. This has main draw-backs in terms of manufacturability, since the handling of large amounts of pure Cs is a basic issue in production lines. Here we present in detail results on PIN-OLEDs comprising a newly developed molecular n-dopant. All the previous OLED performance data based on PIN-OLEDs with alkali metal doping could be reproduced and will be further improved in the future. Hence, for the first time, a full manufacturing compatible PIN-OLED is available.