• Title/Summary/Keyword: Phosphorescent materials

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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.

Novel Host materials for Phosphorescent OLEDs with long lifetime

  • Kim, Young-Hoon;Yu, Eun-Sun;Kim, Nam-Soo;Jung, Sung-Hyun;Kim, Hyung-Sun;Lee, Ho-Jae;Kang, Eui-Su;Chae, Mi-Young;Chang, Tu-Won
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.549-552
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    • 2008
  • We have developed a novel bipolar host material with both electron and hole transporting characteristics. Since CGH(Cheil Green Host) has some electron transporting characteristics, it shows increased luminance efficiency in device including TCTA and without HBL(hole blocking layer:BAlq). Maximum power efficency of CGH was 27.4lm/W at the device structure ITO/DNTPD(60)/NPB(20)/TCTA(10)/EML(30)/Alq3(20)/LIF(1)/Al. We measured device performance again without HBL. The result of CGH showing 26.0lm/W is outstanding compared to that of CBP showing 19.1lm/W without holeblocking layer. We also measured lifetime and found to be 205hr at 3000nit, that is significant result compared to the life time of CBP device showing 82hr. CGH shows high device performance with holeblocking layer. Moreover, it shows better device performance and life time than those of CBP without holeblocking.

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A Study on the Highly Efficient Green Organic Light-Emitting Diodes Using Phosphorescent materials (인광물질을 사용한 고효율 녹색 유기 발광 소자에 관한 연구)

  • Jung, Jin-Ha;Shim, Ju-Yong;Kang, Myung-Goo;Oh, Hwan-Sool
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.276-277
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    • 2006
  • 본 연구에서는 인광 발광 물질인 host재료, CBP에 guest로 인광색소인 $Ir(ppy)_3$을 첨가하여 광학적, 전기적 특성을 보았다. $Ir(ppy)_3$ 색소를 서로 다른 중량비로 첨가할 때의 소자들의 특성을 평가하였다.$ Ir(pppy)_3$을 3.125%의 중량비로 하였을 때 가장 좋은 휘도특성을 보였다. 소자의 기본구조는 glass/ITO/${\alpha}-NPD(300{\AA})$/CBP:$Ir(ppy)_3(300{\AA})$/$BCP(80{\AA})$/$Alq_3(200{\AA})$)/$Al(1000{\AA})$로 하였다.

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A high efficiency green phosphorescent OLED with simple double emission layer structure

  • Kim, Sun-Young;Park, Tae-Jin;Jeon, Woo-Sik;Kim, Jong-Sil;Pode, Rachamdra;Jang, Jin;Kwon, Jang-Hyuk
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.30-33
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    • 2008
  • Using a $Ir(ppy)_3$ doped in hole and electron transport host materials, simple three layers green PHOLEDs comprising double emissive layers have been fabricated. A low driving voltage value of 3.3 V to reach a luminance of $1000\;cd/m^2$ and maximum current- and power-efficiency values of 53.9 cd/A and 57.8 lm/W are demonstrated in this simple structure phosphorescent OLED.

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Effects of Emission Layer Thickness on the Efficiency of Blue Phosphorescent Organic Light Emitting Diodes with Triple Layer Structure (발광층 두께가 삼층 구조 청색 인광 OLED의 효율 특성에 미치는 영향)

  • Seo, Yu-Seok;Moon, Dae-Gyu
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.2
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    • pp.143-147
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    • 2010
  • We have fabricated simple triple-layer blue-emitting phosphorescent organic light emitting diodes (OLEDs) using different thicknesses of N,N'-dicarbazolyl-3,5-benzene (mCP) host layers doped with bis[(4,6-di-fluorophenyl)-pyridinate-N,$C^{2'}$]picolmate (FIrpic) guest materials. The thicknesses of mCP:FIrpic layers were 5, 10, and 30 nm. Driving voltage, current and power efficiencies were investigated. The current efficiency was higher in the 10 nm thick mCP:FIrpic device, resulting from the better electron-hole balance. The device with 10 nm mCP:FIrpic layer exhibited the maximum current efficiency of 22.5 cd/A and power efficiency of 7.4 lm/W at a luminance of 1000 cd/$m^2$.

A study on the characteristics of the OLEDs using Ir complex for the blue phosphorescence (Ir complexes를 이용한 인광 발광 소자의 전기 광학적 특성 관한 연구)

  • Kim, So-Young;Kim, Jun-Ho;Seo, Ji-Hyun;Kim, Young-Kwan
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.510-511
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    • 2005
  • Several iridium based complexes were investigated as blue phosphorescent dopants. They are achieved about 100 % quantum efficiencies due to utilization of both singlet and triplet excitons in the radiative processes. We have fabricated phosphorescent OLED with 8 % Ir$(ppz)_3$ as a triplet emissive dopnat in diverse host materials. In this study, the CBP obtained the luminance efficiency of 0.20 cd/A adapts to the host material. Furthermore, we synthesize metalorganic phosphor complexs based on Ir heavy metal with different ligands as to $Ir(ppz)_2acac$, $(Im)_2Ir(acac)$, $(Im-R)_2Ir(acac)$.

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Effect of Ancillary Ligand, Phenyl group, on the Emission Spectrum of Pt(II) Complex Useful for Organic Light-Emitting Device (유기전기발광소자에 사용될 수 있는 백금 착물에 대해 보조리간드 phenyl 기가 발광스펙트럼에 미치는 영향)

  • Lee, Seung-Hee;Lee, Ho-Joon
    • Journal of the Korean Applied Science and Technology
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    • v.25 no.2
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    • pp.265-268
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    • 2008
  • Among the efforts to increase the efficiency of organic light-emitting device (OLED), there is a way: doping phosphorescent materials. As a phosphorescent material, complexes of heavy transition metal, platinum, were synthesized. $Cl^-$ ion and phenyl group were used as ancillary ligands with 2-(2-pyridyl)benzimidazole (pbi) as a chromophore. The complexes were analysed by FAB-mass spectrometer and absorption and emission spectra were obtained. A phenyl group was able to shift the emission band of the complex even if it's not a chromorphore.

Effects of Dopant Concentration on the Electrical and Optical Properties of Phosphorescent White Organic Light-emitting Diodes with Single Emission Layer (도판트 농도가 단일 발광층 인광 백색 OLED의 전기 및 광학적 특성에 미치는 영향)

  • Do, Jae-Myoun;Moon, Dae-Gyu
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.4
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    • pp.232-237
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    • 2014
  • We have fabricated white organic light-emitting diodes (OLEDs) by co-doping of red and blue phosphorescent guest emitters into the single host layer. Tris(2-phenyl-1-quinoline) iridium(III) [$Ir(phq)_3$] and iridium(III)bis[(4,6-di-fluorophenyl)-pyridinato-$N,C^{2^{\prime}}$]picolinate (FIrpic) were used as red and blue dopants, respectively. The effects of dopant concentration on the emission, carrier conduction and external quantum efficiency characteristics of the devices were investigated. The emissions on the guest emitters were attributed to the energy transfer to the guest emitters and direct excitation by trapping of the carriers on the guest molecules. The white OLED with 5% FIrpic and 2% $Ir(phq)_3$ exhibited a maximum external quantum efficiency of 19.9% and a maximum current efficiency of 45.2 cd/A.

Effects of Spacer Inserted Inside the Emission Layer on the Efficiency and Emission Characteristics of Phosphorescent Organic Light-emitting Diodes (발광층 내의 스페이서가 인광 OLED의 효율 및 발광 특성에 미치는 영향)

  • Seo, Yu-Seok;Moon, Dae-Gyu
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.6
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    • pp.377-382
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    • 2014
  • We have investigated the effects of spacer layer inserted between blue and red doped emission layers on the emission and efficiency characteristics of phosphorescent OLEDs. N,N'-di-carbazolyl-3,5-benzene (mCP) was used as a host layer. Iridium(III)bis[(4,6-di-fluorophenyl)- pyridinato-N,$C^2$']picolinate (FIrpic) and tris(1-phenyl-isoquinolinato-$C^2$,N)iridium(III) [Ir(piq)3] were used as blue and red dopants, respectively. The emission layer structure was mCP (1-x) nm/mCP:$Ir(piq)_3$ (5 nm, 10%)/mCP (x nm)/mCP:FIrpic (5 nm, 10%). The thickness of mCP spacer layer was varied from 0 to 15 nm. The emission from $Ir(piq)_3$ and the efficiency of the device were dominated by energy transfer from mCP host and FIrpic molecules, and by diffusion of mCP host triplet excitons.