• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.43-46
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• 2007

Though bottom emission AM-OLED has advantages in respect of mass production, the bottom emission type is underrated due to its low aperture ratio and low color gamut, compared with top emission type. In this paper, we demonstrate that the color gamut up to 89 % can be simply achieved by depositing dielectric multilayers, whose thicknesses are determined using an optical simulation program, prior to formation of Si layer.

• Bulletin of the Korean Chemical Society
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• 제35권6호
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• pp.1670-1674
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• 2014

Two red emitters, 2-(7-(4-(diphenylamino)styryl)-2-methyl-4H-chromen-4-ylidene)malonitrile (Red 1) and 2-(7-(julolidylvinyl)-2-methyl-4H-chromen-4-ylidene)malonitrile (Red 2) have been designed and synthesized for application as red-light emitters in organic light emitting diodes (OLEDs). In these red emitters, the julolidine and triphenyl moieties were introduced to the emitting core as electron donors, and the chrome-derived electron accepting groups such as 2-methyl-(4H-chromen-4-ylidene)malononitrile were connected to electron donating moieties by vinyl groups. To explore the electroluminescence properties of these materials, multilayered OLEDs using red materials (Red 1 and Red 2) as dopants in $Alq_3$ host were fabricated. In particular, a device using Red 1 as the dopant material showed maximum luminous efficiencies and power efficiencies of 0.82 cd/A and 0.33 lm/W at $20mA/cm^2$. Also, a device using Red 2 as a dopant material presented the CIEx,y coordinates of (0.67, 0.32) at 7.0 V.

• 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.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.803-805
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• 2009

A highly efficient blue organic light-emitting diode (OLED) was fabricated by using a novel polymer host, poly[3-(carbazol-9-ylmethyl)-3-methyloxetane]. The resultant solution-processed device showed a markedly high efficiency of 29.7 lm/W at 100 cd/$m^2$ by doping 24 wt% blue dye bis(3,5-difluoro-2-(2-pyridyl)-phenyl-(2-carboxy pyridyl) iridium (III).

• ETRI Journal
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• 제36권5호
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• pp.847-855
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• 2014

We developed a highly refractive index planarization layer showing a very smooth surface for organic light-emitting diode (OLED) light extraction, and we successfully prepared a highly efficient white OLED device with an embossed nano-structure and highly refractive index planarization layers. White OLEDs act as an internal out-coupling layer. We used a spin-coating method and two types of $TiO_2$ solutions for a planarization of the embossed nano-structure on a glass substrate. The first $TiO_2$ solution was $TiO_2$ sol, which consists of $TiO_2$ colloidal particles in an acidic aqueous solution and several organic additives. The second solution was an organic and inorganic hybrid solution of $TiO_2$. The surface roughness ($R_a$) and refractive index of the $TiO_2$ planarization films on a flat glass were 0.4 nm and 2.0 at 550 nm, respectively. The J-V characteristics of the OLED including the embossed nano-structure and the $TiO_2$ planarization film were almost the same as those of an OLED with a flat glass, and the luminous efficacy of the aforementioned OLED was enhanced by 34% compared to that of an OLED with a flat glass.

• Journal of Ceramic Processing Research
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• 제13권spc2호
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• pp.260-264
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• 2012

We have investigated the effect of ambient gases on the structural, electrical, and optical characteristics of IZO thin films intended for use as anode contacts in the organic light emitting diodes (OLED) devices. These IZO thin films were deposited on the PES film by radio frequency (RF) magnetron sputtering under different ambient gases (Ar, Ar + O2, and Ar + H2) at room temperature. In order to investigate the influences of the ambient gases, the flow rate of oxygen and hydrogen in argon has been changed from 0.1 sccm to 0.5 sccm, respectively. All the IZO thin film has an (222) preferential orientation regardless of ambient gases. The electrical resistivity of the IZO film increased with increasing O2 flow rate, whereas the electrical resistivity decreased sharply under an Ar + H2 atmosphere and was nearly similar regardless of the H2 flow rate. The change of electrical resistivity with changes in the ambient gas composition was mainly interpreted in terms of the charge carrier concentration rather than the charge carrier mobility. All the films showed the average transmittance over 85% in the visible range. The OLED device was fabricated with different IZO substrates made with the configuration of IZO/α-NPD/DPVB/Alq3/LiF/Al in order to elucidate the performance of the IZO substrate. The current density and the luminance of OLED devices with IZO thin films deposited in 0.5 sccm H2 ambient gas are the highest amongst all other films.

• 한국정보통신학회논문지
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• 제11권12호
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• pp.2361-2365
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• 2007

OLED 소자의 전기적 특성을 온도 변화에 따라 측정을 하였다. OLED 소자는 N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-diphenyl-4,4'-diamine (TPD)를 정공 수송층으로, tris(8-hydroxyquinoline) aluminum(Alq3)를 전자송층 및 발광층으로 사용하였다. 전압-전류 특성은 온도 범위 $10K{\sim}300K$에서 측정하였다. OLED 소자에서의 전도 메커니즘의 해석은 Fowler-Nordheim tunneling 법을 이용하여 해석하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1803-1804
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• 2006

In this paper, device performances of organic lightemitting diodes (OLEDs) will be presented for AMOLED and general illumination applications. Various types of advanced devices were developed to enhance the power efficacy and luminous efficiency. Here we also demonstrated longer lifetime AM-OLED structures, which lifetime is about 100 hours until $L/L_0$ reaches 0.99.

• 대한전자공학회논문지SD
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• 제42권12호
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• pp.13-18
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• 2005

본 논문에서는 Poly-ethylene-terephthalate (PET) 기판 위에 Organic Thin Film Transistor (OTFT)와 Organic Light Emitting Diode (OLED)를 직렬 연결시킨 픽셀과 64 x 64 픽셀로 구성된 어레이를 제작하여 동작을 시연하였다. OTFT는 PET 기판과의 호환성을 고려하여 Poly 4-vinylphenol을 게이트 절연체로, 펜타센을 활성층으로 사용하여 제작되었다. 개별 소자 수준에서는 이동도가 $1.0\;cm^2/V{\cdot}sec$로 나타났으나, 어레이에서는 $0.1\~0.2\;cm^2/V{\cdot}sec$로 약 10배 정도 감소하였다. 어레이의 동작을 분석하였고 OTFT의 OLED에 대한 전류구동능력을 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.105-110
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• 2006

The highly integrated nature of polymer based organic light emitting diode (POLED) microdisplay technology, coupled with low voltage and low power electroluminescent light generation, combine to offer a very promising technology for use in portable and personal electronics products. We briefly describe the technology before discussing how to engineer the color gamut using whiteemitting polymer materials, microcavity device structure and color filter absorbance.