• Title/Summary/Keyword: Red electroluminescence

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The study on Red device using PBD as a Hole Blocking Layer (PBD를 Hole Blocking Layer로 이용한 적색발광의 EL 소자 제작에 관한 연구)

  • Kang, Min-Woong;Kim, Jong-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.11a
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    • pp.499-501
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    • 2002
  • 본 연구에서는 ETL층으로 널리 알려져 있는 PBD(2-(4-biphenyl)-5-(4-tert-butylphenyl) -1.3,4oxadiazole)를 HBL(Hole-blocking layer) 물질로 이용 하고 Nile red를 사용하여 적색 발광의 EL(electroluminescence) 소자를 제작 평가하였다. 일반적인 유기 EL 소자의 구조인 Anode/HTL(Hole Transport Layer)/ETL(Electron Transport Layer)/Cathode로 이루어져 있다. 여기에 HTL과 ETL사이에 HBL를 추가하여 EL 소자의 성능을 향상 시킬 수 있으면, 이러한 구조의 최종 소자를 제작 EML(emitting layer; Nile red)의 두께 및 임계전압을 달리 하여 소자 의 특성을 평가 연구 하였다.

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Electroluminescence of a red fluorescent dye doped in an $Alq_{3}$:rubrene Mixed Host

  • Kang, Hee-Young;kang, Gi-Wook;Lee, Chang-Hee
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.948-951
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    • 2003
  • The electroluminescence (EL) properties were studied in organic light-emitting diodes with a red fluorescent dye, 4- (dicyanomethylene)- 2- tert-butyl-6 (1,1,7,7-tetramethyljulolidyl-9-enyl)- 4H- pyran (DCJTB) doped into tris-(8-hydroxyquinoline)aluminum ($Alq_{3}$), rubrene and the mixed matrix of $Alq_3$ and rubrene. The device with DCJTB doped into the $Alq_{3}$:rubrene mixed host shows an efficient red emission from DCJTB with a negligible EL emission from $Alq_{3}$ and a lower EL onset voltage compared to the device with DCJTB doped into the $Alq_{3}$ only host. The quantum efficiency is almost temperature-independent for the device with the $Alq_3:rubrene$ mixed host. The results indicate that recombination of injected electrons and holes occurs on rubrene and subsequent energy transfer to DCJTB dominates in the device with the $Alq_{3}$:rubrene mixed host.

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Studies on the Energy Transfer in LED Containing the Layer made of the Blends of Hole Transporting Polymer and Organic Phosphorescent Dye (정공전달고분자와 유기형광염료의 혼합물 박막이 이용된 발광소자의 에너지 전달특성 연구)

  • Kim, Eugene;Jung, Sook
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.11
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    • pp.1192-1198
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    • 2004
  • Hole transporting polymer(poly[N-(p-diphenylamine)phenylmethacrylamide], PDPMA) was doped with nile red dye at various concentrations to study the influence of doping on the energy transfer during light emitting processes. Organic LEDs composed of ITO/blend(PDPMA -nile red)/ Alq$_3$/Al as well as thin films of blend(PDPMA -nile red)/ Alq$_3$ were manufactured for investigating photoluminescence, electroluminescence, and current-voltage characteristics. Atomic Force Microscopy was also used to observe surface morphology of the blend films. It was found that such doping. significantly influences the efficiency of the energy transfer from the Alq$_3$ layer to blended layer and the optical/electrical properties could be optimized by choosing the right concentration of the dye molecule. The results also showed a interesting correlation with the morphological aspect, i.e. the optimum luminescence at the concentration with the least surface roughness. When the concentration of nile red was 0.8 wt%, the maximum energy transfer could be achieved.

The fabrication of europium complex electroluminescence using BCP as hole blocking layer

  • Liang, Yujun;Zhang, Hongjie;Kim, Beung-Kwon;Jung, Young-Ho;Park, Jo-Yong;Myung, Kwang-Shik;Khatkar, S.P.;Han, Sang-Do
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.11a
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    • pp.578-580
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    • 2002
  • A bright and highly monochromatic red organic electroluminescent device based on a poly(N-vinylcarbazole) host was made. The device structure consists of poly(N-vinylcarbazole) dispersed with a europium complex as an emitting layer and a hole blocking layer of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP). The EL cell exhibited just characteristic emission of europium ion.

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Conjugated Copolymers by Horner-Emmons Polycondensation and Electroluminescence Characteristics

  • Park, Lee-Soon;Jeong, Seung-Won;Kim, Sang-Dae;Seo, Hyeon-Jin
    • Journal of Information Display
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    • v.2 no.2
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    • pp.45-51
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    • 2001
  • Four types of conjugated polymers, poly(MEHPV-PV), poly(MEHPV-BPV), poly(MEHPV-AV) and poly(PZV-AV) were synthesized by Homer-Emmons reaction using potassium tert-butoxide. The Homer-Emmons reaction gave electroluminescent(EL) copolymers in good yield. Of the EL copolymers synthesized, poly(PZV-AV) containing phenothiazinylene vinylene and anthrylene vinylene as repeat unit exhibited red color in the light emitting diode(LED) which was very close to the NTSC standard red. Besides, double layer LED made with $Alq_3$ electron transport layer exhibited both enhanced emission intensity and efficiency compared to the single layer LED.

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Red-emissive Y2SiO5:Eu3+ Phosphor-based Electroluminescence Device (Y2SiO5:Eu3+ 형광체 기반 적색 전계 발광 소자)

  • Hyunjee Jung;Sunho Park;Jong Su Kim;Hoon Heo
    • Journal of the Semiconductor & Display Technology
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    • v.22 no.1
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    • pp.83-87
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    • 2023
  • Y2SiO5 Powder based on silicon and yttrium is well known as powder phosphors due to their excellent sustainability and efficiency. A new electroluminescence device was fabricated with Y2SiO5:Eu3+ powder phosphors though a simple screen printing method. The powder-dispersed electroluminescence device consisted of the Y2SiO5:Eu3+ powder-dispersed phosphor layer and BaTiO3-dispersed dielectric layer. The annealing temperature of the phosphor for the best powder electroluminescence performance was optimized to high temperature in ambient atmosphere though a solid-state reaction. The Eu3+ concentration for the best device performance was also investigated and furthermore, the thermal dependence of the electroluminescence intensity was investigated at the operating voltage at 100℃, which is the Curie temperature of the BaTiO3 layer. And the intensity was exponentially increased with voltage and increased linearly with frequency.

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Highly Efficient Red Phosphorescent OLEDs Based on Ir(III) Complexes with Fluorine-substituted Benzoylphenylpyridine Ligand

  • Kang, Hyun-Ju;Lee, Kum-Hee;Lee, Suk-Jae;Seo, Ji-Hyun;Kim, Young-Kwan;Yoon, Seung-Soo
    • Bulletin of the Korean Chemical Society
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    • v.31 no.12
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    • pp.3711-3717
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    • 2010
  • Four orange-red phosphorescent Ir(III) complexes were designed and synthesized based on the benzoylphenylpyridine ligand with a fluorine substituent. Multilayered OLEDs with the device structure, ITO/2-TNATA/NPB/CBP : 8% Ir(III) complexes/BCP/Liq/Al, were fabricated using these complexes as dopant materials. All the devices exhibited orange-red electroluminescence and their electroluminescent properties were quite sensitive to the structural features of the dopants in the emitting layers. Among these, the maximum luminance ($14700\;cd/m^2$ at 14.0 V) was observed in the device containing Ir(III) complex 1 as the dopant. In addition, its luminous, power and quantum efficiency were 11.7 cd/A, 3.88 lm/W and 9.58% at $20\;mA/cm^2$, respectively. The peak wavelength of electroluminescence was 606 nm with CIE coordinates of (0.61, 0.38) at 12.0 V. The device also showed stable color chromaticity with various voltages.

Red Fluorescent Organic Light-Emitting Diodes Using Modified Pyran-containing DCJTB Derivatives

  • Lee, Kum-Hee;Kim, Sung-Min;Kim, Jeong-Yeon;Kim, Young-Kwan;Yoon, Seung-Soo
    • Bulletin of the Korean Chemical Society
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    • v.31 no.10
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    • pp.2884-2888
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    • 2010
  • Two red fluorescent DCJTB derivatives (Red 1 and 2) based on modified pyrans were synthesized and their electroluminescent properties were investigated. Multilayered OLEDs were fabricated with the device structure of ITO/NPB (40 nm)/Red 1, 2 or DCJTB (0.5 or 1%): $Alq_3$ (20 nm)/$Alq_3$ (40 nm)/Liq (2 nm)/Al. All devices exhibited efficient red emissions. In particular, a device containing emitter Red 2 as a dopant in the emitting layer, the maximum luminance was $8737\;cd/m^2$ at 12.0 V, the luminous and power efficiencies were 2.31 cd/A and 1.25 lm/W at $20\;mA/cm^2$, respectively. The peak wavelength of the electroluminescence was 638 nm with the CIE (x,y) coordinates of (0.63, 0.36) at 7.0 V.

Efficient red organic light-emitting devices based on electrophosphorescence (전기인광을 이용한 고효율 적색 유기 전기발광소자)

  • Song, Won-Jun;Kang, Gi-Wook;Park, Su-Yeon;Seoul, Chang;Lee, Chang-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.04a
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    • pp.121-124
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    • 2000
  • Achieving red light-emitting diodes with high quantum and luminous efficiency is required to fabricate the full-color organic electroluminescence display. In this work, we report that devices with 2.3,7,8,12,13,17,18-Octaethyl-21H,23H-porphine palladium (II) (PdOEP), doped into tris(8-Hydroxyquinolinato)-aluminum (III) (Alq3) show a narrow deep red emission (670nm). In addition, PdOEP has been used as host material in which red dyes such as 4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) doped in order to fabricate efficient red-emitting diodes.

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