• Title, Summary, Keyword: Phosphorescent OLEDs

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Electrical Characteristics of Green Emitting Phosphor $Ir(PPY)_3$ Doped OLEDs

  • Kim, Jun-Ho;Kim, Yun-Myung;Ha, Yun-Kyung;Kim, Young-Kwan;Kim, Jung-Soo
    • KIEE International Transactions on Electrophysics and Applications
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    • v.11C no.3
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    • pp.53-57
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    • 2001
  • The organic light-emitting devices (OLEDs) based on fluorescence have low efficiency due to the requirement of spin-symmetry conservation. By using the phosphorescent material, internal quantum efficiency can reach 100%, compared with 25% in the case of the fluorescent material. Thus, phosphorescent OLEDs have recently been extensively studied and shown higher internal quantum efficiency than the conventional OLEDs. In this study, we investigated the characteristics of the phosphorescent OLEDs with the green emitting phosphor, $Ir(ppy)_3$ (tris(2-phenylpyridine)iridium). The device with a structure of ITO/TPD$Ir(ppy)_3$ doped in BCP/BCP/$Alq_3$/Li:Al/Al was fabricated, and its electrical and optical characteristics were studied. By changing the doping concentration of $Ir(ppy)_3$, we fabricated several devices and investigated their characteristics.

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Characteristics of phosphorescent OLEDs and flexible OLED fabricated indium-zinc-tin-oxide anode (IZTO 애노드를 이용하여 제작한 인광 OLED 및 플랙시블 OLED 특성)

  • Choi, Kwang-Hyuk;Bae, Jung-Hyeok;Moon, Jong-Min;Jeong, Jin-A;Kim, Han-Ki;Kang, Jae-Wook;Kim, Jang-Joo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.399-400
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    • 2007
  • In this work, we have investigated the characteristics of the phosphorescent OLED and flexible OLED fabricated on IZTO/glass and IZTO/PET anode film grown by magnetron sputtering, respectively. Electrical and optical characteristics of amorphous IZTO/glass anode exhibited similar to commercial ITO anode even though it was deposited at room temperature. In addition, the amorphous IZTO anode showed higher work function than that of the commercial ITO anode after ozone treatment for 10 minutes. Furthermore, a phosphorescent OLED fabricated on amorphous IZTO anode film showed improved current-voltage-luminance characteristics, external quantum efficiency and power efficiency in contrast with phosphorescent OLED fabricated on commercial ITO anode film. This indicates that IZTO anode is promising alternative anode materials for anode in OLEDs and flexible OLEDs.

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Study on the Characteristics of Organic EL Device Using Phosphorescence (인광을 이용한 유기 EL 소자 특성 연구)

  • Kim, Young-Kwan;Sohn, Byoung-Chung;Kim, Jun-Ho
    • Journal of the Korean Applied Science and Technology
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    • v.18 no.3
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    • pp.186-190
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    • 2001
  • By fabricating the organic light-emitting devices (OLEDs) based on phosphorescent material, the internal quantum efficiency can reach 100%, compared to 25% in the case of the fluorescent material. Thus, the phosphorescent OLEDs have recently been extensively studied and showed higher internal quantum efficiencies then the conventional OLEDs. In this study, we investigated the characteristics of the phosphorescent OLEDs, with the green emitting phosphor, $Ir(ppy)_{3}$, (tris(2-phenylpyridine)iridium). The devices with a structure of $ITO/TPD/Ir(ppy)_{3}$ doped in the host material $/BCP/Alq_{3}/Li:Al/Al$ were fabricated, and its electrical and optical characteristics were studied. By changing the doping concentration of $Ir(ppy)_{3}$, we fabricated several devices and investigated the device characteristics. OLEDs doped into BCP by 10% showed the best characteristics. For 10% doped OLEDs, the maximum luminance of was over 10000 $cd/m^{2}$, and the maximum power efficiency was 7.14 lm/W.

High efficiency multiple quantum well device structure in red phosphorescent OLEDs

  • Park, Tae-Jin;Jeon, Woo-Sik;Jang, Jin;Pode, Ramchandra;Kwon, Jang-Hyuk
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.196-199
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    • 2009
  • We report the multiple quantum well (MQW) structure for highly efficient red phosphorescent OLEDs. Various triplet quantum well devices from a single well to five quantum wells are realized using a wide band-gap hole and electron transporting layers, narrow band-gap host and dopant material, and charge control layers (CCL). The maximum external quantum efficiency of 14.8 % with a two quantum well device structure is obtained, which is the highest value among the red phosphorescent OLEDs using same dopant.

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Extremely low doping technology in phosphorescent OLEDs

  • Jeon, Woo-Sik;Park, Tae-Jin;Kim, Sun-Young;Pode, Ramchandra;Jang, Jin;Kwon, Jang-Hyuk
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.1516-1519
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    • 2008
  • We report extremely low doping technology in phosphorescent organic light emitting diodes(PHOLEDs). Highly efficient red PHOLEDs with excellent energy transfer characteristics even under 1 % doping condition have been demonstrated. Results reveal efficient host-dopant system to realize highly efficient PHOLEDs and useful cost saving way by reduction of expensive Ir complex dopants.

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A Study on the improvement in efficiencies of Organic-Light Emitting Devices Using the Phosphor, Ir(PPy)$_3$ (인광물질 인 Ir(PPy)$_3$를 이용한 유기전기발광소자의 효율 개선에 관한 연구)

  • 김준호;김윤명;구자룡;이한성;하윤경
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.178-181
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    • 2001
  • The organic light-emitting devices (OLEDs) based on fluorescence have low efficiencies due to the requirement of spin-symmetry conservation. By using the phosphorescent material, the internal quantum efficiency can reach 100 %, compared to 25 % in the case of the fluorescent material. Thus, the phosphorescent OLEDs have recently been extensively studied and showed higher internal quantum efficiencies then the conventional OLEDs. In this study, we investigated the characteristics of the phosphorescent OLEDs, with the green emitting phosphor, Ir(ppy)$_3$ (tris(2-phenylpyridine)iridium). The devices with a structure of ITO/TPD/Ir(PPy)$_3$ doped in the host material/BCP/Alq$_3$/Li:Al/Al were fabricated, and its electrical and optical characteristics were studied. By changing the doping concentration of Ir(PPy)$_3$ and the host materials, we fabricated several devices and investigated the device characteristics.

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Study on the Characteristics and Fabrication of Organic Light Emitting Devices Using the Synthesised Phosphorescent Metal Complexes (인광특성이 있는 금속 착물의 합성과 그 물질을 이용한 소자 제작 및 소자 특성 평가)

  • Kim, Young-Kwan;Sohn, Byoung-Chung;Kim, Jun-Ho
    • Journal of the Korean Applied Science and Technology
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    • v.19 no.2
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    • pp.97-102
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    • 2002
  • Recently, the phosphorescent organic light-emitting devices (OLEDs) have been extensively studied for their high internal quantum efficiency. In this study, we synthesised several phosphorescent metal complexes, and certified their composition using NMR. We also investigated the characteristics of the phosphorescent OLEDs with the green emitting phosphor, $Ir(ppy)_{3}$. The devices with a structure of indium-tin-oxide(ITO)/N,N'-diphenyl-N,N'-(3-methylphenyI}-1,1'-biphenyl-4,4'-diamine (TPD)/metal complex doped in host materials/2,9-dimethyl-4,7-diphenyl-l,10-phenanthroline(BCP)/tris (8-hydroxyquinolinato) Aluminum($Alq_{3}$)/Li:Al/Al was fabricated, and its electrical and optical characteristics were studied. By changing the doping concentration of tris(2-phenylpyridine)iridium ($Ir(ppy)_{3}$), we fabricated several devices and investigated their characteristics.

The study on the characteristics of organic light emitting devices using Ir (Ir 착화합물을 이용한 유기발광소자의 특성연구)

  • 김준호;표상우;정래영;하윤경;김영관;김정수
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.214-217
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    • 2002
  • The internal quantum efficiency of organic light emitting devices(OLEDs) using fluorescent organic materials is limited within 25% because of the triplet excitons which can hardly emit light. So there has been considerable interest in finding ways to obtain light emission from triplet excitons. One approach has been to add phosphorescent compounds to one of the layers in OLEDs. Then triplet excitons can transfer to these phosphorescent molecules and emit light. In this study, multilayer OLEDs with phosphorescent emitter, Iridium complexes were prepared. The devices with a structure of ITO/TPD/Ir complex doped in the host material/Alq3/Li:Al/Al were fabricated, and its electrical and optical characteristics were studied. Using various Ir complexes and the host materials, we fabricated several devices and investigated the device characteristics.

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Novel Small Molecular Materials For Solution Green Phosphorescent OLEDs

  • Lee, Ho-Jae;Yu, Eun-Sun;Jung, Sung-Hyun;Kim, Hyung-Sun;Kang, Eui-Su;Chae, Mi-Young;Chang, Tu-Won
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.791-793
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    • 2009
  • We have developed novel small molecular materials for solution phosphorescent OLEDs having multilayered device structures. These novel materials are applied as an interlayer which is between a buffer layer (or hole injection layer) and an emitting layer to improve the luminance efficiency of solution green phosphorescent OLEDs. In order to form stable double layers by spincoating process, we take the advantage of solubility differences of interlayer materials and emitting materials. Using CIM3 as an interlayer, we have attained the best luminance efficiency, 36 cd/A at a given constant of 2000cd/$m^2$ in the structure of ITO/PEDOT:PSS/CIM3/CIM6:Ir(mppy)$_3$/BAlq/Alq$_3$/LiF/Al.

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Highly Efficient Simple-Structure Red Phosphorescent OLEDs with an Extremely Low Doping Technology

  • Jeon, Woo-Sik;Park, Tae-Jin;Kwon, Jang-Hyuk
    • Journal of Information Display
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    • v.10 no.2
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    • pp.87-91
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    • 2009
  • Highly efficient red phosphorescent OLEDs (PHOLEDs) with a simple, organic, triple-layer structure was developed using the narrow-bandgap fluorescent host material bis(10-hydroxybenzo[h] quinolinato)beryllium complex (Bebq2) and the deep-red dopant tris(1-phenylisoquinoline)iridium (Ir(piq)3). The maximum current and power efficiency values of 12.71 cd/A and 16.02 lm/W, respectively, with an extremely low doping technology of 1%, are demonstrated herein. The results reveal a practical, cost-saving host dopant system for the fabrication of highly efficient PHOLEDs involving the simple structure presented herein, with a reduction of expensive Ir dopants.