• 한국응용과학기술학회지
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• 제34권3호
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• pp.562-567
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• 2017

The organic light-emitting diodes are fabricated with six anthracene derivatives containing simple substituents such as phenyl or naphthyl group. The device structure is as in the following: Indium tin oxide (ITO) (180 nm)/4,4-4,4',4"-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (2-TNATA) (30 nm)/4,4'-bis[N-(1-naphthyl)-N-phenyl-1-amino] biphenyl (NPB) (20 nm)/Emitting compound (30 nm)/2,2',2"-(1,3,5-Benzinetriyl)-tris (1-phenyl-1-H-benz-imidazole) TPBi (40 nm)/lithium quinolate (Liq) (2 nm)/Al (100 nm). In the emitting layer the anthracene derivatives are used without any dopant. All the six devices show blue emissions. Among the tested diodes, the one with 9-(2-naphthyl)-10-(p-tolyl) anthracene (2-NTA) exhibited luminous efficiency, power and external quantum efficiencies of 3.26 cd/A, 0.98 lm/A, 2.8 % at $20mA/cm^2$.

• 한국전기전자재료학회논문지
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• 제21권1호
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• pp.68-72
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• 2008

AlGaInP high-brightness LEDs(HB-LEDs) have gained importance a variety of application operating in the red, orange, yellow and yellow-green wavelength. The light generated from inside LED chips should be emitted to the air through the surfaces of the chips. However, because of the differences between the semiconductor and air or epoxy's refractive index, some of the light was blocked so that caused lowering external quantum efficiency. In this study, nano-scale roughness on the top-GaP layer of AlGaInP epitaxial wafer was fabricated to improve' the brightness of AlGaInP LEDs. Nano-scale roughness was made by ICP dry etcher. Our AlGaInP LEDs with nano-scale roughness has higher brightness (about 28.5 %) than standard AlGaInP LEDs.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.26.1-26.1
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• 2011

We investigated the atomic layer deposition (ALD) process for nitrogen doped ZnO and the application for n-ZnO : N/p-Si (NW) coaxial hetero-junction photodetectors. ALD ZnO:N was deposited using diethylzinc (DEZ) and diluted $NH_4OH$ at $150^{\circ}C$ of substrate temperature. About 100~300 nm diameter and 5 um length of Si nanowires array were prepared using electroless etching technique in 0.108 g of $AgNO_3$ melted 20 ml HF liquid at $75^{\circ}C$. TEM images showed ZnO were deposited on densely packed SiNW structure achieving extraordinary conformality. When UV (360 nm) light was illuminated on n-ZnO:N/p-SiNW, I-V curve showed about three times larger photocurrent generation than film structure at 10 V reverse bias. Especially, at 660 nm wave length, the coaxial structure has 90.8% of external quantum efficiency (EQE) and 0.573 A/W of responsivity.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.889-892
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• 2003

Effects of $N_{2}$ plasma treatment of the Al bottom cathode on the characteristics of top emission inverted organic light emitting diodes (TEIOLEDs) were studied. TEIOLEDs were fabricated by depositing an Al bottom cathode, a tris-(8-hydroxyquinoline) aluminum $(Alq_{3})$ emitting layer, an N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-diphenyl-4,4'diamine (TPD) hole transport layer, and an indium tin oxide (ITO) top anode sequentially. The Al bottom cathode layer was subjected to $N_{2}$ plasma treatment before deposition of the $Alq_{3}$ layer. X-ray photoelectron spectroscopy suggested that the existence of and the amount of $AIN_x$ between the $Alq_{3}$ emitting layer and the Al bottom cathode significantly affect the characteristics of TEIOLEDs. The maximum external quantum efficiency of the TEIOLED with an Ai bottom cathode subjected to $N_{2}$ plasma treatment for 30 s was about twice as high as that of the TEIOLED with an untreated Al bottom cathode.

• 한국전기전자재료학회논문지
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• 제18권7호
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• pp.641-646
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• 2005

To fabricate a single layer white organic light emitting diode (OLED), a novel non-conjugated blue emitting material PPPMA-co-DTPM copolymer was synthesized containing a perylene moiety unit with hole transporting and blue emitting ability and a triazine moiety unit with electron transporting ability. The devices were fabricated using PPPMA-co-DTPM $(PPPMA[70\;wt\%]:DTPM[30\;wt\%])$ copolymer by varying the doping concentrations of each red, green and blue fluorescent dye, by molecular-dispersing into Toluene solvent with spin coating method. In case of ITO/PPPMA-co-DTPM:TPB$(3\;mol\%):C6(0.04\;mol\%):NR(0.015\;mol\%)/Al$ structure, as they were molecular-dispersing into 30 mg/ml Toluene solvent, nearly-pure white light was obtained both (0.325, 0.339) in the CIE coordinates at 18 V and (0.335, 0.345) at 15 V. The turn-on voltage was 3 V, the light-emitting turn-on voltage was 4 V, and the maximum external quantum efficiency was $0.667\%$ at 24.5 V. Also, in case of using 40 mg/ml Toluene solvent, the CIE coordinate was (0.345, 0.342) at 20 V.

• Transactions on Electrical and Electronic Materials
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• 제11권3호
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• pp.145-148
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• 2010

White organic light emitting devices were fabricated to improve the stability through a structural change using the two peak emission method. The fabricated devices were composed of indium tin oxide (100 nm)/ $\alpha$-NPD (30 nm)/4,40-bis(2,20-diphenylvinyl)-1,10-biphenyl (DPVBi, d: variable)/DPVBi: Rubrene (40 nm)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline(5 nm)/ $Alq_3$(5 nm)/ Al (100 nm). A DPVBi for blue emissions was used as the host material in the emitters. The doping concentration of the Rubrene was fixed at 2.0% (by weight). The white emission with Commission Internationale De L'Eclairage coordinates of (0.3342, 0.3439) occurred at 14 V with a thickness d of 1 nm. It was insensitive to the drive voltage, and the devices had a maximum luminance of $211\;cd/cm^2$. At 19 V, the current density and maximum external quantum efficiency were $173\;mAcm^2$ and 0.478%, respectively.

• Journal of Information Display
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• 제11권3호
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• pp.123-127
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• 2010

Fluorescent white organic light-emitting diodes showing high color-rendering indices (CRIs) of up to 81 was demonstrated, with a silicon-cored anthracene derivative (PATSPA) doped with DPAVBi utilized as the deep-blue host and dye materials, and the commercial dyes rubrene and DCM2 utilized as the orange- and red-light-emitting dyes. The devices, consisting of three emissive layers, showed bright-white-light emission, but the ratio of the blue peak to the orange and red peaks changed with the current density and the thickness of the blue emissive layer. A high CRI was achieved with the use of a deep-blue emitter doped in a novel host and by optimizing the blue-layer thickness. The device with a blue-layer thickness of 10 nm showed the Commission Internationale de l'Eclairage (CIE) color coordinate of (0.33, 0.35), a high CRI of 81, and a moderate external quantum efficiency of 2% at a current density of $2.5\;mA/cm^2$.

• 폴리머
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• 제26권4호
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• pp.543-550
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• 2002

곁사슬에 정공 및 전자 전달체로 triphenylamine moiety와 triazine moiety를 갖는 새로운 공중합체를 합성하였다. ITO/공중합체와 발광물질 (DCM, coumarin 6, DPvBi)/Al으로 구성되는 단층형 유기 EL 소자는 정공 전달 단위체와 전자 전달 단위체 비율이 6:4와 방광물질의 함유량이 30 wt%일 때 최고의 외부 양자 효율을 나타내었다. 특히 위에서 제작한 유기 EL 소자는 각각 발광물질에 상응하는 빨강 (620 nm), 초록 (520 nm)과 파랑색 (450 nm)의 빛을 발광하였다. 최고 휘도는 DC 12V에서 ITO/공중합체 (6:4)와 DCM (30 wt%)/Al으로 구성되는 소자를 구동하였을 때 500 cd/$m^2$이었다.

• ETRI Journal
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• 제27권4호
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• pp.405-410
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• 2005

High quality indium tin oxide (ITO) thin films were grown by pulse laser deposition (PLD) on flexible polyethersulphone (PES) substrates. The electrical, optical, and surface morphological properties of these films were examined as a function of substrate temperature and oxygen pressure. ITO thin films, deposited by PLD on a PES substrate at room temperature and an oxygen pressure of 15 mTorr, have a low electrical resistivity of $2.9{\times}10^{-4}{\Omega}cm$ and a high optical transmittance of 84 % in the visible range. They were used as the anode in organic light-emitting diodes (OLEDs). The maximum electro luminescence (EL) and current density at 100 $cd/m^2$ were 2500 $cd/m^{2}$ and 2 $mA/m^{2}$, respectively, and the external quantum efficiency of the OLEDs was found to be 2.0 %.

• 한국진공학회지
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• 제21권4호
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• pp.185-192
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• 2012

Light Emitting Diode (LED) 칩의 크기는 전도를 통한 열의 방출에 있어 면적의 확대로 인한 열 밀도의 감소와 칩의 외부양자효율 변화로 인하여 LED 칩의 p-n 정션 온도와 패키지의 열 저항에 영향을 미친다. 본 연구에서는 16칩 LED 패키지에서 칩의 크기가 0.6 mm와 1 mm인 두 가지 경우에 대하여 순전압(forward voltage)을 측정하였고, 순간열분석법(thermal transient analysis)을 이용하여 정션 온도와 열 저항을 평가하였으며, 이를 LED 칩의 전기적인 특성과 LED 패키지의 구조적인 특성과 연관하여 해석하였다.