• Title, Summary, Keyword: Electroluminescence(EL)

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Optical Properties of Graphene Doped ZnS:(Cu,Al) Inorganic Electroluminescence Devices by Screen Printing (Graphene을 첨가하여 스크린 프린팅으로 제작한 ZnS:Cu,Al 무기 전계발광 소자의 광특성)

  • Jo, Sung Ho;Lee, Sang Nam
    • Korean Journal of Optics and Photonics
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    • v.26 no.5
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    • pp.265-268
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    • 2015
  • An inorganic electroluminescence device based on a green ZnS:(Cu,Al) phosphor was fabricated by a screen printing method. Graphene was added to the phosphor layer to increase the electroluminescence intensity. As the graphene concentration increased, the photoluminescence intensity decreased; on the other hand, the electroluminescence intensity increased, up to 0.6 wt%.

Determination of photo- and electroluminescence quantum efficiency of semiconducting polymers (전기발광고분자의 양자효율 측정)

  • 이광희;박성흠;김진영;진영읍;서홍석
    • Korean Journal of Optics and Photonics
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    • v.13 no.2
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    • pp.128-133
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    • 2002
  • In a recent effort to develop polymer light-emitting diodes (LEDs) as promising flat panel display components, measurements of reliable absolute photoluminescence (PL) and electroluminescence (EL) efficiency for polymer materials are required. In this work, we performed the measurement of PL and EL efficiency of luminescent polymers using an integrating sphere technique. The external PL efficiency of MEH-PPV was estimated to be 8 ($\pm$2)% together with the value of 0.02 1m/W for the external EL efficiency. This PL efficiency is in good agreement with published values, indicating that our PL efficiency measurements are somewhat legitimate. We believe this study might contribute to the research and development of organic materials for optoelectronic devices.

A Study on Characteristics of Light Emitting Diode with Porous Silicon (다공성 실리콘을 이용한 LED의 발광 특성에 관한 연구)

  • Lee Sung-Hoon;Lee Chi-Woo
    • Journal of the Korean Electrochemical Society
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    • v.3 no.1
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    • pp.39-43
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    • 2000
  • The light emitting diode (LED) was fabricated from n-type porous silicon. We investigated both the current-voltage characteristics of the LED with various electrode materials and changes of electroluminescence with applied current density. Also we probed changes in electroluminescence as a function of operation time at a given current. In order to Improve the contact area between the electrode material and porous silicon layer, we deposited indium on porous silicon layer by electroplating and investigated the electric characteristics of the LED and changes of electroluminescence.

Optical and Electrical Characteristics of Chirped Quantum Dot Structures for the Superluminescent Diodes with Wide Spectrum Bandwidth (파장대역폭이 넓은 고휘도 발광소자를 위한 Chirped 양자점 구조의 광/전기 특성 분석)

  • Han, Il-Ki
    • Journal of the Korean Vacuum Society
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    • v.18 no.5
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    • pp.365-371
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    • 2009
  • We analyzed photoluminescence (PL) and electroluminescence characteristics of various chirped quantum dot structures. Peaks in EL curves were contributed by excited states of quantum dots (QD), while those in PL curves by grounded states. Based on these characteristics, we suggested that superluminescent diodes with wide spectral bandwidth may be developed if chirped QD structures are designed to make a contribution by ground states to EL characteristics.

The Synthesis and EL Properties of Polycarbazole Derivatives (Polycarbazole 유도체의 합성과 EL 특성)

  • Ryu, Jung-Yi;Lee, Tae-Hoon;Cho, Chong-Rae;Chung, Su-Tae;Son, Se-Mo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.1026-1029
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    • 2003
  • Polycarbazole derivatives have been investigated for emitting materials of PLED. We synthesized two polymers containing carbazole chromophor, which are different from bonding position. We investigated the spectra of their absorption, photoluminescence, electroluminescence.

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Electroluminescence Properties from Blend films of poly(3-hexylthiophene) and poly(N-vinylcarvazole) (P3HT와 PVK 블렌드 막에서의 전계 발광 특성)

  • Kim, Dae-Jung;Kim, Shang-Gi;Gu, Hal-Bon;Jung, Un-Jo;Park, Ge-Chun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.972-975
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    • 2002
  • Electroluminescence(EL) devices based on organic thin layers have attracted lot of interests because of their application as display. One of the problems is red material. It offered a short life and poor emission efficiency to boot. In this study, this problem can be solved by using a multi-layer device structure. Organic electroluminescent devices which are composed of organic thin multi-layer films are fabricated. The basic structure is ITO / Emitting layer / LiP / Al EL device in which Hole transport/Electron blocking PVK layer was blending. We demonstrate the enhancement of eletroluminescence (EL) from blends of poly(3-hexylthiophene) in poly(N-vinylcarvazole). The emitting layer is consisted of a host material(PVK) and a guest emitting material(P3HT). It was showed higher EL intensity and their electro-optical properties were investigated.

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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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    • 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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Modifications of ITO Surfaces in Organic EL Devices by $O_2$ Plasma Treatment (O$_2$ 플라즈마 처리에 의한 ITO 표면개질 변화에 따른 유기 EL 소자 특성)

  • 박상무;김형권;이덕출
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.6
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    • pp.261-266
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    • 2003
  • We investigated the effect of oxygen plasma treatment of indium-tin oxide(ITO) surface on the performance of electroluminescence(EL) devices. ITO surface treated oxygen plasma has been analyzed using atomic force microscope(AFM) and X-ray photoelectron spectroscopy(XPS), to investigate the relations between the properties of the ITO surface and the properties of the current-voltage-luminance(I-V-L) characteristics of the fabricated OLED with the structure of ITO(plasma treatment) / TPD / Alq$_3$/ Al. It is found that the oxygen plasma treatment of ITO anode improve the hole injection of the OLED due to the modification of the surface states. The treated ITO anode nay be low voltage with high luminance efficiency.

Syntheses of Improved Polymer/Organic Materials for Electroluminescence(EL) Device and Electro-Optical Characteristics(Ⅱ) Properties of EL Device using Squarylium Dye as Emitting Material (고기능 EL소자용 고분자/유기 재료의 합성 및 전기 광학적 특성(Ⅱ) Squarylium 색소를 이용한 EL소자의 특성)

  • Kim, Sung Hoon;Bae, Jin Seok;Hwang, Seok Hwan;Park, Lee Soon
    • Journal of the Korean Chemical Society
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    • v.41 no.3
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    • pp.144-149
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    • 1997
  • Organic electroluminescence devices(ELD) were fabricated using by molecularly doped method with N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine(TPD) as a hole transport agent, squarylium dye as an emitting agent, and side chain liquid crystalline polymer(MCH) as matrix for TPD. An indium-tin-oxide(ITO) coated glass and an Mg electrode were used as the hole and the electron injecting electrode, respectively. The highest stability of ELD was obtained by spin coating method using dichloroethane as a solvent at a polymer/TPD concentration of 0.005 wt%. For the EL cell with ITO/polymer-TPD/SQ dye/Mg structure, we achieved light red luminescence at a current of 102 mA/$cm^2$ with an applied voltage of 23 V.

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Preparation and Characteristics of Organic Electroluminescence Devices using Multilayer Structure with Carrier Transport Materials (다층막 구조를 이용한 유기 EL소자의 제작과 특성에 관한 연구)

  • Lee, Sang-Youn;Kim, Young-Kwan;Kim, Jung-Soo
    • Proceedings of the KIEE Conference
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    • pp.1563-1565
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    • 1997
  • Electroluminescence(EL)devices based on organic thin layers have attracted lot of interests because of their possible application as large-area light-emitting display. One of the problems of such devices is lifetime of the cell, where the degradation of the cell is partially due to the crystalliyzation of organic layers. In large part, this problem can be solved by using a multilayer device structure prepared by vapor deposition technique. In this study, blue lightemitting multilayer organic electroluminescence devices were fabricated using Poly (9-vinyl-carbazole) (PVK) and 2-(4'-tert-butylpheny])-5-(4"-bis-phenyl)1,3,4-oxadiazole (PBD) as hole trasport and electron transport material, respectively, where tris(8-hydroxyquinolinate) aluminum (Alq3) was used as a luminescenct material. A cell structure of glass substrate/indume-tin-oxide(ITO)/PVK/$Alq_3$/PBD/Mg:In was employed.

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