• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.165-167
• /
• 2007

The performance of polymer light emitting diode can be improved significantly by interfacial engineering on anode and/or cathode through adjusting the charge injection barriers for holes and electrons. Studies involve CFx and SAM modifications on ITO, thickness and delay time to baking of PEDOT:PSS, and electron injection/hole blocking layer.

• ETRI Journal
• /
• v.18 no.3
• /
• pp.181-193
• /
• 1996

A blue light emitting device has been successfully fabricated using a polymer with regulated conjugation length containing trimethylsilyl substituted phenylenevinylene units. Electroluminescence from the device has an emission maximum at 470 nm. The device shows typical diode characteristics with operating voltage of 20 V and the light becomes visible at a current density of less than $0.5;mA/cm^2$. The electroluminescence spectrum is virtually identical with the photoluminescence spectrum, indicating that the radiation mechanisms are the same for both. A light emitting device using the blend of a large band gap polymer and a small band gap polymer was also fabricated. Light emission from the small band gap polymer shows much improved quantum efficiency, but there is no light emission from the large band gap polymer. Quantum efficiency of the blend increases up to about two orders of magnitude greater than that of the small band gap polymer with increasing proportion of the large band gap polymer. The improvement in quantum efficiency is interpreted in terms of exciton transfer and the hole blocking behaviour of the large band gap polymer. Finally, we have fabricated a patterned flexible light emitting device using the high quantum efficiency polymer blend system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.05a
• /
• pp.106-108
• /
• 2004

We have investigated the photolithographic patterning method of light emitting polymer film for polymer light emitting diodes (PLED). Blue light emitting polymers based on polyfluorene, which can be cured photochemically to yield an insoluble form, have been synthesized using Ni(0) mediated Yamamoto polymerization. The relationship between patterning property and several variables such as the intensity of the exposed UV light, the concentrations of additives, has been studied by using optical microscope analysis, UV/visible spectroscopy, and photoluminescence. We have successfully fabricated PLEDs composed of the patterned emissive layer and their electroluminescence property has been also investigated. In this presentation, the detailed photolithographic patterning method and its application for polymer light emitting display will be discussed.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.779-780
• /
• 2009

New inverted architecture of a hybrid inorganic-organic light-emitting diode, utilizing ZrO2 electron-injecting layer, is presented. The thickness of the ZrO2, as well as the annealing of the light-emitting polymer, is found critical to obtain good performance. A range of light-emitting polymers is shown to operate efficiently in the proposed architecture.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.648-650
• /
• 2007

We demonstrate highly efficient White Polymer Electrophosphorescent Light-emitting Diode using newly developed green and red light emitting heteroleptic iridium complex, Ir-(pq)2tpy, and blue light emitting fluorescent dopant, BczVBi. The best luminous efficiency reached 28cd/A with maximum luminance of 87000cd/m2. The scheme for determining optimum device architecture and dopant concentrations were constructed.

• Journal of Information Display
• /
• v.8 no.3
• /
• pp.1-4
• /
• 2007

The influence of a silane layer on the performances of polymer light emitting diode(pLED)s has been studied. Glycidoxypropyltrimethoxysilane(GPS) with an epoxy functional group was used as a surface modifier for ITO substrates. The GPS layer was inserted between an ITO and a poly(3,4)-ethylenedioxythiophene/polystyrenesulfonate(PEDOT) by wet process and the performances of PLEDs were investigated. The introduction of GPS layer increased the brightness and efficiency of PLEDs by 30%. In addition, the lifetime of PLEDs was also improved considerably by using GPS as a surface modifier.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07b
• /
• pp.1082-1085
• /
• 2003

본 연구에서는 고분자를 사용하여 만든 유기EL소자인 PLED (Polymer Light Emitting Diode)의 제조공정 변화에 따른 소자성능을 연구하였다. PLED의 제작은 크게 ITO 기판 제작, 발광층 및 전극 증착 등의 공정으로 나누어진다. ITO 기판은 사진식각공정으로, 발광층의 증착은 스핀코팅법으로, 전극은 진공증착법으로 각각 제작하였다. 코팅 시 스핀속도 및 점도 조절을 통하여 발광층의 두께를 조절하였고, 스핀코팅 후 건조방법에 따라서 표면의 uniformity와 발광특성을 비교해 보았다. 실험결과 특정 두께에서 발광특성이 우수하게 나타나는 것을 확인할 수 있었다. 그리고 건조방법에 따라 발광층의 표면 uniformity에 차이가 있었으며, 표면 uniformity에 따라 diode의 I-V 특성 경향이 달리 나타났다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.592-594
• /
• 2004

We have investigated the photolithographic patterning method of light emitting polymer film for polymer light emitting diodes (PLEDs). Blue light emitting polymers based on polyfluorene, which can be cured photochemically to yield an insoluble form, have been synthesized using Ni(0) mediated Yamamoto polymerization. The relationship between patterning property and several variables such as the intensity of the exposed UV light, the concentrations of additives, has been studied by using optical microscope analysis, UV/visible spectroscopy, and photoluminescence. We have successfully fabricated PLEDs composed of the patterned emissive layer and their electroluminescence property has been also investigated. In this presentation, the detailed photolithographic patterning method and its application for polymer light emitting display will be discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.04a
• /
• pp.119-122
• /
• 2003

We report a dramatic increase in the photo-stability of a blue-emitting polymer, poly(9,9-dioctylfluorene), achieved by the addition of gold nanoparticles to the polymer. The optical absorption band of gold nanoparticles is tuned to resonate the triplet exciton-ground state band gap energy of the polymer. The photo-oxidation rate of poly(9,9-dioctylfluorene) was drastically reduced by doping the polymer with a very small amount ($10^{-6}-10^{-5}$ volume fraction) of gold nanoparticles. The gold nanoparticles used herein act as the quenching agent of the triplet states and can be directly applied to various blue light emitting polymer thin film ( < 100 nm ) devices.

• Fibers and Polymers
• /
• v.1 no.1
• /
• pp.25-31
• /
• 2000

Poly(3-hexyl thiophene)(P3HT) and poly(3-dodecyl thiophene)(P3DT) were polymerized by oxidative coupling with ferric chloride. The P3HT light-emitting device emitted red light and it could be observable in the ordinary indoor light. The device had the turn-on electric field of about 3$\times$$10^7$ V/m. The maximum electroluminescene (EL) intensity was obtained when the thickness of polymer layer was about 130 nm in IT0/P3HT/Al device. The maximum external quantum yield was 0.002%. The maximum luminance was 21 cd/$m^2$. The EL intensity decreases with increasing the crystallinity of the polymer layer. By using the oriented poly(3-alkyl thiophene)(PAT) layer as an electroluminescent layer in the ITO/polymer/Al light-emitting devices, the polarized EL light emission was observed. The EL intensity ratio of parallel to perpendicular direction to the stretch direction for P3HT was about 1.40.