• 한국진공학회지
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• 제15권6호
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• pp.556-562
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• 2006

플라즈마 디스플레이 패널은 양극과 음극사이의 방전공간을 가진 많은 방전 셀로 구성되어 있다. 네온과 제논가스로 채워진 이 방전공간에서 전기방전이 일어난다. 전자온도가 방전조건에 의하여 정해지며 이온도를 통하여 제논의 함량에 따른 방전전압을 이론적으로 계산할 수 있다. 방전 셀 내의 플라즈마가 147 nm와 173 nm의 극자외선을 방출하고 이 자외선들은 형광물질을 여기하여 가시광선을 방출한다. 이러한 모든 과정에 대한 물리적인 메커니즘의 모델을 만들고 실험에서 측정된 데이터와 모델이 예시하는 결과를 비교한다. 실험 데이터는 이론 결과와 비교적 잘 일치하는 것을 관찰할 수 있다. PDP의 방전과 동작을 더욱 개선하기 위하여 새로운 물질이 필요하고 더 좋은 셀 구조가 요구된다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1129-1132
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• 2005

We report state-of-the-art phosphorescent organic light emitting diode lifetime and efficiency performances for a range of emission colors. Lifetimes in excess of 100,000hrs have been demonstrated at display luminance levels for saturated red emission. External quantum efficiencies close to the theoretical maximum (e.g. 23% without enhanced optical output coupling) are also demonstrated for devices with lifetimes in excess of 15,000hrs at a display level luminance for both orange red and green.

• 한국전기전자재료학회논문지
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• 제26권7호
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• pp.567-574
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• 2013

An optical model is proposed in the white LED using phosphor and LED chip. In this paper a new model that describes the absorption rate and quantum efficiency with increasing the mixing ratio of phosphor in silicone, and the allotment of the phosphor absorption optical power in the several phosphor mixing in the silicone. Single phosphor in silicone from the optical measurement data before and after molding, the solution to get the blue optical power and the phosphor emission optical power is proposed. By these solution the absorption rate and the quantum efficiency was obtained. The model with single phosphor mixing in the silicone the validity was confirmed.

• 한국전기전자재료학회논문지
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• 제22권6호
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• pp.512-515
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• 2009

We have fabricated blue phosphorescent organic light emitting diodes (PHOLEDs) using a 3,5'-N,N'-dicarbazole-benzene (mCP) host and iridium (III) bis[(4,6-difluorophenyl)-pyridinato-N,$C^{2'}$] picolinate (Flrpic) guest materials, The Flrpic was partially doped into the mCP host layer, for investigating recombination zone, current efficiency, and emission characteristics of the blue PHOLEDs. The recombination of electrons and holes takes place inside the mCP layer adjacent to the mCP/hole blocking layer interface. The best current efficiency was obtained in a device with an emission layer structure of mCP (10 nm)/mCP:Flrpic (20 nm, 10%). The high current efficiency in this device was attributed to the confinement of Ffrpic triplet excitons by the undoped mCP layer with high triplet energy, which blocks diffusion of Ffrpic excitons to the adjacent hole transport layer with a lower triplet energy.

• 대한전자공학회논문지SD
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• 제37권6호
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• pp.17-23
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• 2000

본 연구에서는 Sq색소를 이용하여 적색발광의 디바이스를 제작하고, 발광효율을 증가시키기 위해 OXD7과 $Alq_3$층을 발광층과 음극사이에 삽입하여 그 효과를 관측하고, 기구특성을 검토하였다. 정공운송층으로서 TPD, 발광층 호스트재료로서 $Alq_3$, 게스트 재료로서 Sq를 사용하였다. 그 결과 $Alq_3$층의 삽입은 효율을 증가시킬 수 있었지만, 삽입된 $Alq_3$층에서의 발광 때문에 색순도 높은 적색발광을 얻지 못했다. OXD7층의 삽입은 정공을 블로킹하고 정공을 누적시킨다. 이는 전자와 정공의 재결합확률을 증가시키기 때문에 색순도 높은 적색발광을 유지하면서 휘도 특성과 발광효율이 향상되었다.

• Journal of Information Display
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• 제9권2호
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• pp.18-21
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• 2008

We report on white organic light-emitting diodes (WOLEDs) based on single white dopants, $Ir(pq)_2$($F_2$-ppy) and $Ir(F_2-ppy)_2$(pq), where $F_2$-ppy and pq are 2-(2,4-difluorophenyl) pyridine and 2-phenylquinoline, respectively. The similar phosphorescent lifetime of two ligands lead to luminescence emission in two ligands simultaneously. However, the emission color of the devices was reddish, because the energy was not transferred efficiently from the 4,4,N,N'-dicarbazolebiphenyl (CBP) to the $F_2$-ppy ligand, due to the small band gap of the CBP. Accordingly, we used 1,4-phenylenesis(triphenylsilane) (UGH2) with a large band gap, instead of CBP as the host material. As a result, it was possible to adjust the emission color by the host material. The luminous efficiency of the device with $Ir(F_2-ppy)_2$(pq) doped in UGH2 was about 11 cd/A at 0.06 cd/$m^2$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.402-403
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• 2007

High-efficiency white organic light-emitting diodes (WOLEDs) were fabricated with two emissive layers and a spacer was sandwiched between two phosphorescent dyes which were, bis(3,5-Difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium III (FIrpic) as the blue emission and bis(5-acetyl-2-phenylpyridinato-N,C2') acetylacetonate $((acppy)_2Ir(acac))$ as the red emission. This spacer effectively prevented a triple-triple energy transfer between the two phosphorescent emissive layers with blue and red emission that was showed a improved lifetime. The white device showed Commission Internationale De L'Eclairage $(CIE_{x,y})$ coordinates of (0.33, 0.42) at $22400\;cd/m^2$, a maximum luminance of $27300\;cd/m^2\;at\;0.388\;mA/cm^2$, and a maximum luminous efficiency of 26.9 cd/A.

• 한국표면공학회지
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• 제54권3호
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• pp.112-118
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• 2021

Dy³⁺- and Eu³⁺-codoped BaWO₄ phosphors for white light-emitting diode were synthesized with different activator ions via a solid-state reaction process. The structural, morphological, and optical properties of the BaWO₄:Dy³⁺,Eu³⁺ phosphors were investigated as a function of Eu³⁺ concentration at a fixed concentration of Dy³⁺ ions. XRD patterns exhibited that all the synthesized phosphors had a tetragonal system, irrespective of the concentrations of Dy³⁺ and Eu³⁺ ions. The excitation spectra of the synthesized phosphors were composed of three intense bands centered at 251, 355, and 393 nm and several weak peaks. For the BaWO₄:Dy³⁺,Eu³⁺ phosphors synthesized with 1 mol% of Eu³⁺, the emission spectra under ultraviolet excitation at 393 nm showed two strong blue and yellow bands at 485 and 577 nm corresponding to the ⁴F_9/2⁶H_15/2 and ⁴F_9/2⁶H_13/2 transitions of Dy³⁺ ions, respectively and several weak bands in the range of 600-700 nm resulting from the 4f transitions of Eu³⁺ ions. As the concentration of Eu³⁺ ions increased, intensities of the blue and yellow emission bands gradually decreased while those of the red emissions increased rapidly and the energy transfer efficiency from Dy³⁺ to Eu³⁺ ions was 95.3% at 20 mol% of Eu³⁺. The optimum white light emission with x=0.363, y=0.357 CIE 1931 chromaticity coordinates was obtained for the sample doped with 5 mol% Dy³⁺ and 1 mol% of Eu³⁺.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.679-682
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• 2004

$SrGa_2S_4$:Eu green phosphor and SrS:Eu red phosphor have been synthesized by co-precipitation method, respectively. Two sulfide phosphors were influenced by oxygen defect in host materials. Excitation spectra of these phosphors have high efficiency at the long wavelength region. And emission efficiency is increased under the excitation wavelength of 465nm. The combination of thiogallate green phosphor and sulfide red phosphor based on blue light InGaN chip has made it possible to emit white light.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1454-1456
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• 2007

The electrical and the optical properties of blue organic light-emitting devices (OLEDs) with a multiple emitting layer (EML) acting as electron and hole trapping layers were investigated. While the luminance efficiency of the OLEDs with a multiple EML was very stable, regardless of variations in the applied voltage.