• 대한전자공학회논문지TE
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• 제39권2호
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• pp.11-16
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• 2002

본 논문은 백색유기발광소자를 구현하기 위해서 빛의 3원색인 적, 녹, 청색의 형광색소를 적절하게 배합하여 단일층 백색광을 얻었다. 개별적인 적색, 녹색, 청색 유기고분자 발광소자의 성능이 가장 우수한 특성을 조사한 후 최적화된 값으로 백색유기발광소자를 제작하였다. PVK와 Bu-PBD를 각각 70wt%, 30wt%로 혼합한 용액에 Nile Red(0.015mol%), Coumarin6(0.04mol%), TPB(3mol%)를 각각 첨가하여 백색발광소자를 제작하였을 때 구동전압이 20V에서 휘도 785cd/$m^2$, 색좌표가 (0.32, 0.34)인 백색광을 얻었다

• 조명전기설비학회논문지
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• 제18권4호
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• pp.15-21
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• 2004

광속구(integrating sphere photometer), 분광기(monochromator)등을 이용하여 노랑색(Y), 녹색(G), 백색(W)의 SMD(surface mounted device)형태의 HB LED(high brightness light emitting diode)에 대한 광속(luminous flux, LF), 상관 색온도(correlated color temperature, CCT), CIE 색도좌표(chromaticity coordinate CC)등 광특성을 실험하여 그 결과치를 비교 분석하였고, 백색 LED에 대해서는 연색지수를 고찰하였다.

• Journal of Information Display
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• 제8권2호
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• pp.20-24
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• 2007

Efficient white organic light-emitting diodes are fabricated with the blue and red electroluminescent (EL) units electrically connected in a stacked tandem structure by using a transparent doped organic p/n junction. The blue and red EL units consist of the light-emitting layer of 1,4-bis(2,2-diphenyl vinyl)benzene (DPVBi) and 4-dicyanomethylene-2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[i,j] quinolizin-8-yl)vinyl]-4H-pyran) (DCM2) doped tris(8-hydroxyquinoline) aluminum $(Alq_3)$, respectively. The organic p-n junction consists of ${\alpha}-NPD$ doped with $FeCl_3$ (15 % by weight ratio) and $Alq_3$ doped with Li (10 %). The EL spectra exhibit two peaks at 448 and 606 nm, resulting in white light-emission with the Commission Internationale d'Eclairage (CIE) chromaticity coordinates of (0.36, 0.24). The tandem device shows the quantum efficiency of about 2.2 % at a luminance of 100 $cd/m^2$, higher than individual blue and red EL devices.

• 한국응용과학기술학회지
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• 제26권3호
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• pp.357-361
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• 2009

The authors have demonstrated white oraganic light-emitting diodes (WOLED) using 1,4-bis[2-(4'-diphenylaminobiphenyl-4-yl)vinyl]benzene as fluorescent blue emitter and iridium(III) bis(5-acetyl-2-phenylpyridinato-N,C2') acetylacetonate as phosphorescent red emitter. The optimized WOLED using red host material as bis(2-methyl-8-quinolinato) -4-phenylphenolate exhibited proper color stability in comparison with the control device using 4,4'-N,N'-dicarbazole-biphenyl as red host. The white device showed a maximum luminance of 21100 $cd/m^2$ at 14 V, luminous efficiency of 9.7 cd/A at 20 $mA/cm^2$, and Commission Internationale de I'Eclairage ($CIE_{x,y}$)coordinates of (0.32, 0.34) at 1000 $cd/m^2$. The devices also exhibited the color shift with ${\Delta}CIE_{x,y}$ coordinates of ${\pm}$ (0.01,0.01) from 100 to 20000 $cd/m^2$.

• 전자공학회논문지 IE
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• 제43권2호
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• pp.1-6
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• 2006

Two-wavelength에 의한 백색 유기발광소자를 청색계열의 발광재료 DPVBi와 오렌지계열의 발광재료 Rubrene 물질을 사용하여 제작하였다. 소자의 구조는 glass/ITO/TPD$(225{\AA})$/DPVBi/Rubrene/BCP$(210{\AA})/Alq_3(225{\AA})/Al(1000{\AA})$로 하였다. 청색 발광층인 DPVBi와 오렌지색 발광층인 Rubrene층의 두께비율를 변화시켜 가면서 백색광을 구현하였다. 청색발광재료 DPVBi층의 두께가 210${\AA}$ 이고 오렌지색 발광재료의 Rubrene 층의 두께가 180${\AA}$일 때 구동전압 15V에서 $1000cd/m^2$ 휘도와 (0.29, 0.33)의 CIE 색좌표값을 갖는 백색광을 얻었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.90-93
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• 2002

In the surface pressure-area isotherms of mixed monolayers, mixtures containing as much as 30 mol% of AA form stable condensed monolayer while the monolayer without AA is in the expanded state because PVK take on 3D collapsed. All of the mixed monolayers with 0, 10, 20 and 30 mol% of AA could be readily transferred onto ITO substrate at 16, 17, 24 and 26 mN/m, respectively. The monolayer containing 30 mol% of AA, however, showed a roughness value of 28A and became homogeneous decreasing with the phase separation. We fabricated organic EL device of ITO/CuPc/MEL/BBOT/iLiF/Al using mixed monolayer of 13, 19 and 25 layer deposited by LB method as a emitting layer. In the voltage-current characteristics of EL device, current density was much smaller than that of the spin-coated devices. It may due to the large contact resistance existed at the interface of LB layer/organic layer inhibit carrier injection to the emitting layer. EL spectra of device showed peaks at 450. 470, 505, 555 and 650 nm and the white light emission indicate the CIE coordinate x=0.306, y=0.353.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1403-1406
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• 2007

An effective WOLED structure was demonstrated which improved a luminous efficiency and white color chromaticity independent on applied bias by employing effective carrier transporting layer, without any alteration of emissive materials. The modified WOLEDs exhibited 2 times higher luminous efficiency than the control device and showed balanced white emission during an operation.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1407-1410
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• 2007

This work reports on three primary color fluorescent white organic light emitting diode (WOLED) with simple device structure where only a part of the hole transporting layer was doped with dye. The maximum luminance of the device reaches $35000\;cd/m^2$ at a drive voltage below 11V and external quantum efficiency of the device is above 1% in the wide range of luminance from 10 to $35000\;cd/m^2$ and reaches its highest 1.6% at $500\;cd/m^2$. The chromaticity coordinate shift of the device is negligible in this wide range of luminance. The blue shift of emission color with an increase of current density was attributed to the narrowing of recombination zone width with raise of current density.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1294-1296
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• 2005

We have fabricated white organic light emitting diodes. To obtain balanced white emission and improve the efficiency of devices, thin electron blocking layer (TEBL) was inserted between the emitting layers. We showed that the effective injection of electrons through the optimization of TEBL (a - NPD) embodied the balance of spectra and had a possibility of getting white emission. In a device with 0.3 nm a-NPD, it had a maximum power efficiency of 3.80 lm/w at 250 $cd/m^2$, a luminance of 1200 $cd/m^2$ at 100 $mA/cm^2$ , and the CIE coordinates were (0.353, 0.357).

• 제어로봇시스템학회논문지
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• 제14권6호
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• pp.511-514
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• 2008

2-wavelength type white OLED devices have been made consisted of two layers; a layer with blue light emitting DPVBi host and other EML layer with yellow emitting rubrene dopant. New method to get white emitting device has been suggested by varying thicknesses of the DPVBi layer. The ITO/2-TNATA($150{\AA}$)/NPB($350{\AA}$)/DPVBi($35{\AA}$)/DPVBi:rubrene (2wt%,$200{\AA}$)/DPVBi($100{\AA}$)/Alq_3($50{\AA}$)/LiF($5{\AA}$)/Al($1000{\AA}$) structure has showed optimum results in CIE coordinates of (0.3233, 0.33). OLED devices with this structure has properties of $1.2d/m^2$ at turn-on voltage of 3.9V and $1037cd/m^2$ at 7.9V. This structure has advantages of simple fabrication and easy to emit the white color.