• 한국진공학회지
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• 제19권3호
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• pp.184-189
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• 2010

두 가지의 형광도판트를 이용하여 제작된 단일 발광층 유기발광다이오드(OLEDs)는 ITO / NPB ($700{\AA}$) / MADN : C545T - 1.0% : DCJTB - 0.3% ($300{\AA}$) / Bphen ($300{\AA}$>) / LiF ($10{\AA}$) / Al ($1,000{\AA}$)으로 구성되었다. C545T와 DCJTB는 각각 녹색과 적색 도판트로 사용되었고, 호스트 물질인 MADN에 대해서 각각 다른 농도로 도핑하였다. 이러한 두 가지 형광도 판트를 사용한 제적화된 OLED는 8.42 cd/A의 효율과 6 V에서 $3169 cd/m^2$의 발광 휘도와 (0.43, 0.50)의 색좌표를 가졌다. 이러한 OLED 구조의 electroluminescence는 각각 C545T와 DCJTB에 따라 500 nm와 564 nm의 피크를 가졌다. 이러한 결과는 MADN에서 C545T로 C545T에서 DCJTB로 포스터 에너지 전이가 일어났음을 설명할 수 있다.

• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1475-1482
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• 2011

New spiro[benzo[c]fluorene-7,9'-fluorene] (SBFF)-based blue host materials, 9-phenyl-SBFF (BH-4P) and 5,9-diphenyl-SBFF (BH-6DP), were successfully prepared by spiro-formation of 9-phenyl-7H-benzo[c]fluoren-7-one with 2-bromobiphenyl via lithiation and reaction of 5,9-dibromo-SBFF with phenylboronic acid through the Suzuki reaction, respectively. Diphenyl-[4-(2-[1,1;4,1]terphenyl-4-yl-vinyl)-phenyl]-amine (BD-1) and N,N-diphenyl-N',N'-diphenyl-SBFF-5,9-diamine (BD-6DPA) were used as dopant materials. Blue OLEDs with the configuration ITO/N,N'-bis-[4-(di-m-tolylamino)phenyl]-N,N'-diphenylbiphenyl-4,4'-diamine (DNTPD)/bis[N-(1-naphthyl)-N-phenyl]benzidine (NPB)/host:5% dopant/SFC-137/Al-LiF were prepared from the two host materials doped with BD-1 and BD-6DPA dopants and the devices composed of BH-4P and BH-6DP doped with BD-6DPA showed blue EL spectra at 458 and 463 nm at 7 V and luminance efficiencies of 4.58 and 4.88 cd/A, respectively.

• Journal of Information Display
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• 제11권3호
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• pp.123-127
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• 2010

Fluorescent white organic light-emitting diodes showing high color-rendering indices (CRIs) of up to 81 was demonstrated, with a silicon-cored anthracene derivative (PATSPA) doped with DPAVBi utilized as the deep-blue host and dye materials, and the commercial dyes rubrene and DCM2 utilized as the orange- and red-light-emitting dyes. The devices, consisting of three emissive layers, showed bright-white-light emission, but the ratio of the blue peak to the orange and red peaks changed with the current density and the thickness of the blue emissive layer. A high CRI was achieved with the use of a deep-blue emitter doped in a novel host and by optimizing the blue-layer thickness. The device with a blue-layer thickness of 10 nm showed the Commission Internationale de l'Eclairage (CIE) color coordinate of (0.33, 0.35), a high CRI of 81, and a moderate external quantum efficiency of 2% at a current density of $2.5\;mA/cm^2$.

• 한국전기전자재료학회논문지
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• 제27권2호
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• pp.104-109
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• 2014

To operate organic light emitting device (OLED) with alternating current (AC) power source without AC/DC(direct current) converter, we fabricated the fluorescent OLED and measured the emission characteristics with AC and DC. The OLED operated by AC showed higher maximum current efficiency of 8.2 cd/A and maximum power efficiency of 8.3 lm/W. But current efficiency and power efficiency of AC driven OLED showed worse than DC driven OLED at high voltage above 10 V. This result can be explained by the peak voltage of AC was $\sqrt{2}$ times than DC, In case of low driving voltage the emission characteristics were improved by the peak voltage of AC, but in case of high driving voltage the emission efficiencies were decreased by the roll off phenomena. Finally, serial OLED arrays using twelve OLEDs driven by AC 110 V showed average voltage of 9.17 V, voltage uniformity of 99.0%, average luminance of $1,175cd/m^2$, luminance uniformity of 94.4%.

• 한국전기전자재료학회논문지
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• 제28권11호
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• pp.704-710
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• 2015

We studied white organic light-emitting diodes using blue fluorescent and red phosphorescent materials. White single OLEDs were fabricated using SH-1 : BD-2 (3 vol.%) and CBP : $Ir(mphmq)_2(acac)$ (2 vol.%) as emitting layer (EML). The white single OLED using SH-1 : BD-2 (3 vol.% 8 nm) / CBP : $Ir(mphmq)_2(acac)$ (2 vol.% 22 nm) as emitting layer showed maximum current efficiency of 8.8 cd/A, Commission Internationale de l'Eclairage (CIE) coordinates of (0.403, 0.351) at $1,000cd/m^2$, and variation of CIE coordinates with ($0.402{\pm}0.012$, $0.35{\pm}0.002$) from 500 to $3,000cd/m^2$. The white tandem OLED using SH-1 : BD-2 (3 vol.% 12 nm) / CBP : $Ir(mphmq)_2(acac)$ (2 vol.% 18 nm) showed maximum efficiency of 19.6 cd/A, CIE coordinates of (0.354, 0.365) at $1,000cd/m^2$, and variation of CIE coordinates with ($0.356{\pm}0.016$, $0.364{\pm}0.002$) from 500 to $3,000cd/m^2$. Maximum current efficiency of the white tandem OLED was more twice as high as the single OLED. Our findings suggest that tandem OLED was possible to produce improved efficiency and excellent color stability.

• 마이크로전자및패키징학회지
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• 제13권1호통권38호
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• pp.51-55
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• 2006

[ $Alq_3$ ]-C545T 형광 시스템을 이용하여 녹색 발광 고성능 OLED를 제작하고 그 특성을 평가하였다. 소자 제작에서 ITO(Indium Tin Oxide)/glass 위에 정공 주입층으로 2-TNATA [4,4',4'-tris(2-naphthyl-phenyl-phenylamino)-triphenylamine]를, 정공수송층으로 NPB [N,N-bis(1-naphthyl)- N,N'-diphenyl-1,1'-biphenyl-4,4-diamine]를 진공 증착하였다. 녹색 발광층으로는 $Ahq_3$를 호스트로, 545T [10-(2-benzo-thiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-[1]/benzopyrano[6,7,8-ij]-quinolizin-11-one]를 도펀트로 사용하였다. 또한, 전자 수송층으로는 $Alq_3$를 전자 주입층으로는 LiF를 사용하여 ITO/2-TNATA/NPB/$Alq_3$:C-545T/$Alq_3$/LiF/Al 구조의 저분자 OLED를 제작하였다. 본 실험에서 제작된 녹색 OLED는 521 nm의 중심 발광 파장을 가지며, CIE(0.29, 0.65)의 색순도, 그리고 12V의 동작전압에서 7.3 lm/W의 최대 전력효율을 나타내었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.579-581
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• 2004

A new DCM derivative containing the phenoxazine moiety (DCPXZ) has been synthesized for use as a red fluorescent dye molecule in organic light-emitting diodes (OLEDs). The photoluminescence and electroluminescence properties of DCPXZ were examined. The maximum photoluminescence of DCPXZ in chloroform solution ($10^{-5}$ mol) was observed at 616 nm. EL devices were fabricated with the structure ITO/PEDOT-PSS/Cu-PC(15nm)/${\alpha}$-NPD(45nm)/$Alq_3$:DCPXZ(30nm)/$Alq_3$(30nm)/LiF(0.5nm)/Al. The maximum EL emission for the 2.0% DCPXZ-doped device was at 608 nm with CIE coordinates (0.57, 0.42). The EL device exhibited a maximum brightness of 15,000 cd/$m^2$ at 19.4 V and a power efficiency of 1.04 lm/W at a luminance of 100 cd/$m^2$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 춘계학술대회 및 기술 세미나 논문집 디스플레이 광소자
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• pp.25-26
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• 2008

In this paper, the white organic light-emitting diode(OLED)was fabricated using the DPVBi of blue emitting material and a rubrene of orange color of fluorescent dye by vacuum evaporation processes. The device structure of OLED was Glass/ITO/2T-NATA(15nm)/NPB(3nm)/DPVBi(3nm)/DPVBi rubrene[2%](10nm)/DPVBi(25nm)/$Alq_3$ or New-ETL(60nm) /LiF(0.5nm)/ Al(100nm). The device with the $Alq_3$, layer shows orange color, and the luminance of 1000cd/$m^2$ at an applied voltage of 10.4V. On the other hand, the New-En layer results in white color, CIE coordinates of (0.327, 0.323), and the lowered driving voltage of 5V for achieving the same luminance value.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.435-438
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• 2008

We demonstrated the efficient blue organic light-emitting diodes (OLEDs) by employing diarylamino-fluorene derived blue fluorescent molecules as dopants. Among those, a device exhibited blue emission with the luminous efficiency of 11.2 cd/A at $20\;mA/cm^2$, the external quantum efficiency of 9.7% at $20\;mA/cm^2$, and the $CIE_{x,y}$ coordinates of (x=0.163, y=0.259) at 8V.

• 세라미스트
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• 제22권3호
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• pp.218-229
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• 2019

The development of highly efficient thermally activated delayed fluorescence (TADF) materials is an active area of recent research in organic light emitting diodes (OLEDs) since the first report by Chihaya Adachi in 2011. Traditional fluorescent materials can harvest only singlet excitons, leading to the theoretically highest external quantum efficiency (EQE) of 5% with considering about 20% light out-coupling efficiency in the device. On the other hand, TADF materials can harvest both singlet and triplet excitons through reverse intersystem crossing (RISC) from triplet to singlet excited states. It could provide 100% internal quantum efficiencies (IQE), resulting in comparable high EQE to traditional rare-metal complexes (phosphorescent materials). Thanks to a lot of efforts in this field, many highly efficient TADF materials have been developed. This review focused on recent molecular design concept and optoelectronic properties of TADF materials for high efficiency and long lifetime OLED application.