• Journal of Information Display
• /
• v.7 no.3
• /
• pp.19-22
• /
• 2006

White polymeric light-emitting devices (WPLEDs) have been fabricated from polyfluorene-based (PFO) blue and MEH-PPV polymer blending systems. A device structure of ITO / PEDOT:PSS / Blending polymer / Blue polymer / LiF / Al was employed. This structure of double emission layers showed significant improvement of white color shift phenomenon. A current efficiency of 4.67 cd/A (3,900 $cd/m^{2}$, 6.4 V) and a brightness value of 17,600 $cd/m^{2}$ at 9.4 V with (0.34, 0.35) CIE coordinates at 5 V and (0.29, 0.29) at 9 V were achieved achieved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.413-413
• /
• 2007

In recent years, flexible display devices such as liquid crystal display (LCD), organic light emitting diode (OLED), etc. have attracted considerable interest in a wide variety of applications. Polymer substrate is absolutely necessary to realize this kind of flexible display devices. Using the polymer as a substrate, there are lots of advantages including not only mechanical flexibility such as rolling and bending characteristics but also light weights, low cost and so on. In detail, thickness and weights is only one forth and one second of glass substrate, respectively. However, it needs low temperature below $150^{\circ}C$ in the fabrication process comparing to conventional deposition process. The polymer substrate is not thermally stable as much as the glass substrate so that some deformation can be occurred according to variation of temperature. In particular, performance of devices can be easily deteriorated by shrinkage of substrate when heating it. In this paper, pre-annealing and deposition of buffer layer was introduced and studied to solve previously mentioned problems of the shrinkage and followed shear stress.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.523-525
• /
• 2008

Inkjet printing is being considered as an alternative to the conventional lithography in the electronic industry. Surface energy control of substrate is a critical issue in controlling the dimension of microstructures by the inkjet printing. This study introduces the surface energy control of ITO substrate for in/q'et printing of PEDOT/PSS.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.1019-1022
• /
• 2007

High efficiency in Phosphorescent Organic lightemitting diodes using carbazole type exciton blocking layer were investigated and detailed mechanism for light emission process was studied. Efficiency of green PHOLEDs was enhanced by a factor 3.7.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.588-591
• /
• 2004

Polyazomethine type conjugated copolymers containing phenanthridine units, poly(PZ-PTI), were synthesized by Schiff-base reaction. This new conjugated copolymer exhibited improved solubility in common organic solvents due to the presence of alkyl side chains as well as phenanthridine groups. Double layer (ITO/poly(PZ-PTI)/$Alq_3$/Mg) light emitting diode (LED) exhibited enhanced EL emission and efficiency compared to that of single layer (ITO/poly(PZ-PTI)/Mg) LED. With increasing the thickness of $Alq_3$ layer in double layer (ITO/poly(PZ-PTI)/$Alq_3$/Mg) LED the emission peak gradually shifted to the single layer (ITO/$Alq_3$/Mg) LED, confirming good hole transporting behaviour of the synthesized conjugated copolymer.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.469-469
• /
• 2013

Flexible display는 미래의 평판디스플레이 시장으로 꼽히고 있는 대표적인 분야이다. PET, PEN, PI 등의 polymer substrate는 접거나 구부리는 형태로 변형이 가능하기 때문에 차세대 기술로 평가되어지는 Flexible display, Solar cell, OLED 등 다방면에 응용이 가능하다. 또한 ITO는 지금까지 개발된 재료 중에서 가장 투명하고 전기가 잘 통하며, 생산성도 좋기 때문에 이것을 투명전극의 재료로 사용한다. 디스플레이에 사용되는 투명 전도막의 경우, 가시광 영역에서의 투과 및 반사와 같은 광학적 특성은 중요한 요소 중의 하나이다. 투명 전도막의 광흡수, 반사 및 투과즉성은 박막 내에 존재하는 전공밴드의 전자, 자유전자, polar optical phonon 등의 빛과의 반응에 의해 결정된다고 알려져 있다. 본 연구에서는 저온 증착된 ITO 박막의 광학적 특성을 향상시킬 수 있는 방법을 모색하고 기계적, 화학적 특성을 분석하였다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.798-802
• /
• 2009

New blue emitting materials of o,p-TP-EPY and m,m-TP-EPY were synthesized using two terphenyl units with different structures in the new core of indenopyrazine. EL spectrum of o,p-TP-EPY was more blue shifted than m,m-TP-EPY, and external quantum efficiency of o,p-TP-EPY was showed improvement of about 60% compared to efficiency of m,m-TP-EPY.

• Applied Microscopy
• /
• v.44 no.4
• /
• pp.133-137
• /
• 2014

We suggest a facile transmission electron microscopy (TEM) specimen preparation method for the direct (polymer-free) transfer of layer-area graphene from Cu substrates to a TEM grid. The standard (polymer-based) method and direct transfer method were by TEM, high-resolution TEM, and energy dispersive X-ray spectroscopy (EDS). The folds and crystalline particles were formed in a graphene specimen by the standard method, while the graphene specimen by the direct method with a new etchant solution exhibited clean and full coverage of the graphene surface, which reduced several wet chemical steps and accompanying mechanical stresses and avoided formation of the oxide metal.

• Journal of Information Display
• /
• v.4 no.3
• /
• pp.1-5
• /
• 2003

Laser-Induced Thermal Imaging (LITI) is a laser addressed patterning process and has unique advantages such as high-resolution patterning with over all position accuracy of the imaged stripes of within 2.5 micrometer and scalability to large-size mother glass. This accuracy is accomplished by real-time error correction and a high-resolution stage control system that includes laser interferometers. Here the new concept of hybrid system that complement the merits of small molecule and polymer to be used as an OLED; our system can realize easy processing of light emitting polymers and high luminance efficiency of small molecules. LITI process enables the stripes to be patlerned with excellent thickness uniformity and multi-stacking of various functional layers without having to use any type of fine metal shadow mask. In this study, we report a full-color hybrid OLED using the multi-layered structure consisting of small molecules and polymers.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1511-1513
• /
• 2005

The polymer-light emtting diodes(PLEDs) were comprised a design of OLED array, process develop by using ITO thin glass, and fabrication of PDMS stamp by using nanocontact printing. In the study, we describe a different approach for building OLEDs, which is based on physical lamination of thin metal electrodes supported by a PDMS stamp layer against an electroluminescent organic. We develop that devices fabricated in this manner have better performance than those constructed with standard processing techniques. The lamination approach avoids forms of disruption that can be introduced at the electrode organic interface by metal evaporation and has a reduced sensitivity to pinhole or partial pinhole defects. Also, it is easy to build patterned PLED with feature sizes into the nanometer regime. This method provides a new route to PLED for applications ranging from high performance displays to storage and lithography systems, and PLED can used for organic electronics and flexible display.