• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.9
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• pp.1-10
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• 2002

We have done various treatments of indium tin oxide (ITO) surface for organic light-emitting diodes (OLEDs), and investigated the surface states by different surface treatments using atomic force microscopy (AFM) and Auger electron spectroscopy (AES). We have fabricated OLEDs deposited by ultra-high vacuum molecular beam deposition system and studied the characteristics of the OLEDs. We have observed the dramatical improvement of the performance of OLEDs fabricated on ITO substrates treated by $O_2$ plasma treatment reduces the carbon comtamination of ITO surfaces and increases the work function of ITO.

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.244-250
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• 2013

We investigated green phosphorescent organic light-emitting diodes (PHOLEDs) with charge control layer (CCL) to produce high efficiency. The CCL and host material which was 4,4,N,N'-dicarbazolebiphenyl (CBP) of bipolar property can control the carrier movement in emitting layer (EML). The performance improvement by the insertion of CCL was realized to the well confined exciton and the reduced triplet exciton quenching effect in EML. Five types of devices (Device A, B, C, D, and E) were fabricated following the thickness of CCL within EML. The properties of device D using optimized thickness of CCL showed external quantum efficiency of 16.22% and luminous efficiency of 55.76 cd/A, respectively.

• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.335-338
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• 2006

전자수송층과 음극 사이에 $Al_2O_3$를 넣은 이중구조 음극을 갖는 유기발광다이오드를 제작하였다. 제작한 디바이스의 구조는 $ITO/NPB(40\;nm)/Alq_3(60\;nm)/Al_2O_3(0-1.5\;nm)/Al(120\;nm)$로 $Al_2O_3$의 두께를 변화시켰다. $Al_2O_3$의 두께가 0.3 nm일 때는 터널링에 의해서 전자주입이 증가하여 전류와 휘도가 모두 좋아졌다. 반면에 $Al_2O_3$의 두께가 0.5 nm일 때는 전류는 감소하지만 정공과 전자의 비율이 더 좋아져서 전류효율이 크게 향상되었다. 또한 $Al_2O_3$는 엑시톤이 음극과의 계면에서 발광하지 않고 소멸하는 것을 막아주어서 휘도를 증가시켰다.

• Electrical & Electronic Materials
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• v.17 no.7
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• pp.5-11
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• 2004

유기박막 트랜지스터 (Organic Thin Film Transistor : OTFT)에 관한 연구는 1980년 이후부터 시작되었으나 근래에 들어 전 세계적으로 본격적인 연구가 진행되고 있다. 이는 OTFT가 넓은 면적 위에 소자를 제작할 경우, 낮은 공정 온도를 필요로 하는 경우, 또한 구부림이 가능해야 하는 경우, 특히 저가 공정이 필요한 경우 등에 가장 적합한 것으로 생각되고 있기 때문이다. 이러한 OTFT는 미래의 정보표시 장치의 필수적인 요소들과 집적화가 매우 용이하다는 장점을 가지고 있다. 소재의 특성상 유기 발광 다이오드에 쓰이는 발광 유기물과 같은 유기 반도체가 OTFT의 제작에 사용 가능하므로 증착 공정, 물리적 화학적 성질이 매우 유사하다.(중략)

• Proceedings of the KAIS Fall Conference
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• 2006.11a
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• pp.133-134
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• 2006

본 논문에서는 ITO/Glass 기판에 스핀 코팅법(Spin Coating)과 열 증착법(Thermal Evaporation)을 이용하여 ITO/PEDOT:PSS/PVK/PFO-poss/Li/Al 구조를 갖는 청색 고분자 유기전계발광소자를 제작하였다. 청색 고분자 유기발광다이오드 제작시 ITO 전극을 $O_2$ gas를 이용한 Plasma Treatment와 Heat Treatment를 실시하여 기판처리가 제작된 소자의 전기, 광학적 특성에 미치는 영향에 대하여 조사하였다. Plasma와 Heat Treatment를 동시에 처리한 소자에서 가장 우수한 전기, 광학적 특성을 나타냈으며, 기판처리를 하지 않은 경우는 전기, 광학적 특성은 크게 감소하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.89-90
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• 2007

본 연구에서는 ITO/PEDOT:PSS/PFO-poss/LiF/Al 구조를 갖는 고분자 유기발광다이오드(PLED)를 제작하여 ITO 투명 전도막의 전처리 효과가 유기발광 다이오드의 특성에 미치는 영향에 대하여 조사하였다. 최적의 전처리 조건을 찾기 위하여 다양한 플라즈마 처리 조건에 다른 ITO 투명전도막의 표면형상의 변화와 전기적 특성을 관찰하였다. 또한 ITO 투명전도막에 플라즈마 처리와 열처리를 실시하여 PLED 소자를 제작하고 전기 광학적 특성을 조사하여 ITO 투명 전도막의 전처리가 소자의 특성에 미치는 영향을 조사하였다.

• Information Display
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• v.18 no.5
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• pp.3-11
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• 2017

• Korean Journal of Optics and Photonics
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• v.29 no.6
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• pp.262-267
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• 2018

In this paper, we designed a new antireflective film to improve the optical efficiency of organic light-emitting diode displays (OLEDs). The reflection characteristics in the normal and side viewing directions of OLEDs with the antireflective film were calculated, depending on the degree of polarization and transmittance of the currently used polarizer when used in the antireflective film of an OLED. The results showed that when the polarization degree of the commercial polarizer (99.990~99.995%) is lowered to 99.900%, the average reflectance of the antireflective film is increased by about 0.1% (2.5% in terms of rate of increase) which is difficult to notice with the human eye, while the transmittance is increased by 1.63~3.34% (4.2~8.2% in terms of rate of increase). This study provides an optimal design for high-light-efficiency OLEDs with good antireflection properties.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.4
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• pp.37-42
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• 2007

We fabricated the polymer light emitting diodes (PLEDs) with ITO/PEDOT:PSS/PVK/PFO:MEH-PPV/LiF/Al structures. The effect of the thickness of PEDOT:PSS hole injection layer(HIL) on the electrical and optical properties of PLEDs was investigated. In addition, PVK hole transport layer(HTL) was introduced in the PLED device, and compared the properties of the PLEDS with and without PVX layer. All organic film layers were prepared by the spin coating method on the plasma treated ITO/glass substrates. As the thickness of PEDOT:PSS film layer decreased from about 80 nm to 50 nm, the luminance of PLED device increased from $220cd/m^2$에서 $450cd/m^2$. This may be ascribed to the increased transportation efficiency of the holes into the emission layer of PLED. The maximum current density and luminance were obtained fir the PLED device with PVX hole transport layer, showing that the current density and luminance were $268mA/cm^2\;and\;540cd/m^2$ at 12V, respectively. This values were improved by about 14% and 22% in current density and luminance compared with the PLED device without PVK layer.

• The Journal of the Korea Contents Association
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• v.8 no.11
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• pp.18-24
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• 2008

An organic light-emitting diode(OLED) has advantages of low power driving, self light-emitting, wide viewing angle, excellent high resolution, full color, high reproduction, fast response speed, simple manufacturing process, or the like. However, there are still a number of challenges to get over in order to put it to practical use as a high performance display. First of all, the most important thing is to improve the efficiency of the OLED element in order to commercialize it. To this end, its efficiency can be improved by lowering the driving voltage through the improvement of structure of the OLED element and the application of new organic substance. Therefore, in this study, we have manufactured a red OLED element by applying fluorescent dyes to the emitting layer of the element having the structure of ITO/TPD/ Znq2+DCJTB /Znq2/Al and the structure of ITO/CuPc/NPB/ Alq3+DCJTB/Alq3/Al, in order to light-emitting various colors or improve the brightness and the efficiency, and then we have evaluated its electrical and optical characteristics.