• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.115-118
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• 2003

Complex impedances with frequency and voltage variation were analyzed in $ITO/Alq_{3}/Al$(100nm)/Al device structure. At low frequency, complex impedance is mostly expressed by resistive component, and at the high frequency by capacitive component. Also, we have evaluated resistance, capacitance and permittivity.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.143-146
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• 2003

열증착법을 이용하여 copper(II) phthalocyane (CuPc)의 박막을 제작하였다. 기판의 예열 온도를 달리하여 제작된 CuPc의 박막을 x-ray diffraction, SEM, UV visible absorption spectra의 변화를 통해 관찰한 결과 결정의 구조에 따라 ${\alpha}$-phase와 ${\beta}$-phase로 구분할 수 있었다. 이러한 결정 구조의 변화는 CuPc 박막의 전기전도 특성에 영향을 달리하여 유기발광 소자에 응용이 가능할 것으로 예상된다.

• 한국전기전자재료학회논문지
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• 제20권3호
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• pp.257-262
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• 2007

Organic light-emitting diodes (OLEDs) with the high efficieney and long lifetime are of growing interest in next-generation displays. Among the factors influencing OLEDs properties, one of unstable factor is $Alq_3$ cationic species caused by the excess holes resided in $Alq_3$ layer. Therefore, we suppressed the accumulation of excess holes by using the mixed-hole transporting layer (MHTL) of NPB and CBP in multilayer green OLEDs. The devices with MHTL showed improved characteristics in the luminous efficiency and lifetime. More characteristics and the carrier transport mechanism will be discussed.

• 한국전기전자재료학회논문지
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• 제21권3호
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• pp.255-259
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• 2008

Built-in voltage in ITO/$Alq_3$/ Al organic light-emitting diodes was studied by varying a thickness of $Alq_3$ layer using modulated photocurrent technique at ambient condition. A thickness of the $Alq_3$ layer was varied from 100 to 250 nm. From the bias voltage-dependent photocurrent, built-in voltage of the device was able to be determined. The obtained built-in voltage is about 0.8 V irrespective of the $Alq_3$ layer thickness in the device. This value of built-in voltage confirms that the built-in voltage is generated due to a difference of work function of the anode and cathode. The $Alq_3$ layer thickness independent built-in voltage indicates that the built-in electric field in the device is uniform across the organic layer.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.7-9
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• 2008

ITO thin film is generally fabricated by various. methods such as spray, CVD, evaporation, electron gun deposition, direct current electroplating, high frequency sputtering, and reactive DC sputtering. However, some problems such as peaks, bumps, large particles, and pin-holes on the surface of ITO thin film were reported, which caused the destruction of color quality, the reduction of device life time, and short-circuit. Chemical mechanical polishing (CMP) process is one of the suitable solutions which could solve the problems

• 한국컴퓨터산업교육학회:학술대회논문집
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• 한국컴퓨터산업교육학회 2003년도 제4회 종합학술대회 논문집
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• pp.49-54
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• 2003

In this work, we have seen the effect of hole-transporting layer in organic light-emitting diodes using N,N'-biphenyl-N,N'-bis-(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine(TPD) and N,N'-biphenyl-N,N'-bis-(1-naphenyl)-[1,1'-biphenyl]-4,4'-diamine(NPB). NPB is regarded as a better hole trans porting material than TPD, since it has a higher glass transition temperature$(T_g)$. And current -voltage, luminance-voltage and external quantum efficiency of device were measured with the thickness variation of buffer layer using copper phathalocyanine(CuPc) and polytetrafluoroethylene (PTFE) at room temperature. We have obtained an improvement of External quantum efficiency when the CuPc 30[nm] and PTFE 1.0[nm] is used.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.370-373
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• 2001

Temperature-dependent current-voltage characteristics of Organic Light-Emitting Diodes(OLEDs) were studied. The OLEDs were based on the molecular compounds, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-diphenyl-4,4'-diamine (TPD) as a hole transport and tris(8-hydroxyquinoline) aluminum($Alq_3$) as an electron transport and emissive material. The current-voltage characteristics were measured in the temperature range of 10[K] and 300[K]. A conduction mechanism in OLEDs was interpreted in terms of tunneling and trap-filled limited current.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.374-377
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• 2001

We have synthesized poly(3-hexylthiophene)(P3HT), which is the most famous conducting polymer and studied the optical properties of P3HT. And then fabricated the device using P3HT as an emitting layer. For the improve of hole injection from ITO electrode to P3HT emitting layer, we use transparent polyaniline(PANI) electrode. In the voltage-current-luminance characteristics of ITO/PANI/P3HT/LiF/Al device which use the PANI film synthesised during 5 cycle, the device turn on at the 2V and the luminance of $218nW/cm^{2}$ obtained at 12V. External quantum efficiency of ITO/PANI/P3HT/LiF/Al increased at 8V than that of ITO/P3HT/LiF/Al device.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.316-319
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• 2001

Organic light emitting diodes(OLEDs) with a hole injection layer inserted between Indium-Tin-Oxide(ITO) anode and hole transport layer were fabricated. The effect of plasma treatment on the surface properties of Indium-Tin-Oxide(ITO) anode were studied. The electrical and optical characteristics of the fabricated organic light emitting diodes(OLEDs) were also studied. The diode including of plasma treated ITO substrate and the hole injection layer, which showed the luminance of 5280 $cd/m^{2}$ at 8 V

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.130-132
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• 2001

We have investigated current-voltage (I-V) characteristics of organic light-emitting diodes based on $TPD/Alq_3$ organics depending on the application of forward-reverse bias voltage. Luminance-voltage characteristics and luminous efficiency were measured at the same time when the I-V characteristics were measured. We have observed that the I-V characteristics shows a current mxima at low voltage, which is possibly not related to the emission from $Alq_3$.