• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.128-131
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• 2004

유기발광소자(OLED)Glass/indium-tin-oxide(ITO)/Cu-Pc(copper-phthalocyanine)/N.N'-Bis(3-methylphenyl)-1,1'-biphenylbenzidine/tris-(8-hydroquinoline) aluminum(Alq3)/aluminum(Al)의 기본구조로 제작된 OLED에 다양한 전압을 인가하면서, 마이크로파 근접장 현미경을 이용하여 전압인가에 따른 반사계수(S11)와 소자의 전류-전압특성을 측정함으로써 전기적 전도 특성을 연구하였다. 또한 다양한 인가전압에 따른 EL(electro luminance)를 측정하여 소자의 광학적 특성과 전기적 특성을 연구 비교하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.158-161
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• 2004

We have studied a lifetime in organic light-emitting diodes depending on buffer layer. A transparent electrode of indium-tin-oxide(ITO) was used as an anode. And the cathode for electron injection was LiAl. Phthalocyanine Copper(CuPc), Poly(3,4-ethylenedioxythiophene):poly (PEDOT:PSS), or poly (9-vinylcarbazole)(PVK) material was used as a buffer layer. A thermal evaporation was performed to make a thickness of 40nm of TPD layer at a rate of $0.5{\sim}1\;{\AA}/s$ at a base pressure of $5{\times}10^{-6}\;torr$. A material of tris(8-hydroxyquinolinate) Aluminum($Alq_3$) was used as an electron transport and emissive layer. A thermal evaporation of $Alq_3$ was done at a deposition rate of $0.7{\sim}0.8[{\AA}/s]$ at a base pressure of $5{\times}10^{-6}\;torr$. By varying the buffer material, hole injection at the interface could be controlled because of the change in work function. Devices with CuPc and PEDOT:PSS buffer layer are superior to the other PVK buffer layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.534-537
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• 2002

We have studied conduction mechanism that is interpreted in terms of space charge limited current (SCLC) region and tunneling region. The OLEDs are based on the molecular compounds, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) as a hole transport, tris (8- hydroxyquinolinoline) aluminum(III) $(Alq_3)$ as an electron injection and transport and emitting later, copper phthalocyanine (CuPc) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and poly(vinylcarbazole) (PVK) as a buffer layer respectively. Al was used as cathode. We manufactured reference structure that has in ITO/TPD/$Alq_3$/Al. Buffer layer effects were compared to reference structure. And we have analyzed out luminance efficiency-voltage characteristics in ITO/Buffer layer/TPD/$Alq_3$/Al with buffer-layer materials.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.9
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• pp.816-825
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• 2003

Current-voltage-luminance characteristics of organic light-emitting diodes (OLEDs) were measured in the temperature range of 10 K～300 K. Indium-tin-oxide (ITO) was used as an anode and aluminum as a cathode in the device. Organic of N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine (TPD) was used for a hole transporting material, and tris (8-hydroxyquinolinato) aluminum (Alq$_3$) for an electron transporting material and emissive material. And copper phthalocyanine (CuPc), poly(3,4-ethylenedi oxythiophene);poly(styrenesulfonate) (PEDOT:PSS), and poly(N-vinylcarbazole) (PVK) were used for hole-injection buffer layers. From tile analysis of electroluminescence (EL) and photoluminesccnce (PL) spectra of the Alq$_3$, the EL spectrum is more greenish then that of PL. And the temperature-dependent current-voltage characteristics were analyzed in the double and multilayer structure of OLEDS. Electrical conduction mechanism was explained in the region of high-electric and low-electric field. Temperature-dependent luminous efficiency and operating voltage were analyzed from the current-voltage- luminance characteristics of the OLEDS.