• 대한화학회지
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• 제50권6호
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• pp.471-476
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• 2006

Ca1-xSrxS:Ce 형광체를 고상법으로 합성하였다. Ca1-xSrxS:Ce 형광체는 430nm와 470nm 영역에서 강한 흡수가 있다. CaS:Ce은 510 nm와 570 nm에서 발광한다. Ca1-xSrxS:Ce에서 Ca이 Sr으로 치환되면 발광 파장은 단파장 이동을 한다. 청색 발광 다이오드를 사용하여 백색 발광 다이오드를 얻는데 Ca1-xSrxS:Ce 형광체는 푸른빛을 띤 녹색과 황색을 방출할 수 있는 형광체로 사용될 수 있다. 백색 발광 다이오드의 적용을 위한 Ca1-xSrxS:Ce 형광체의 광 특성을 확인하였다.

• 한국전기전자재료학회논문지
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• 제27권9호
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• pp.571-575
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• 2014

We synthesized new materials of $Zn(HPB)_2$ and Ir-complexes as blue or red emitting material. We fabricated white Organic Light Emitting Diodes (OLED) by using $Zn(HPB)_2$ for the blue emitting layer, Ir-complexes for the red emitting layer and $Alq_3$ for the green emitting layer. We fabricated white OLED by using double emitting layers of $Zn(HPB)_2$:Ir-complexes and $Alq_3$. The doping rate of Ir-complexes was varied, such as 0.2%, 0.4%, 0.6%, and 0.8%, respectively. When the doping rate of $Zn(HPB)_2$:Ir-complexes was 0.6%, white emission was achieved. The Commission Internationale de l'Eclairage (CIE) coordinates of the white emission was (0.322, 0.312).

• Rapid Communication in Photoscience
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• 제1권1호
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• pp.19-20
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• 2012

Novel star-shaped imide compounds containing electron-donating triphenylamine and/or electron-withdrawing bis(trifluoromethyl)phenyl side groups were synthesized via a two-step process. First, 3,6-dibromo-benzene-1,2,4,5-tetracarboxylic acid (2B4BA) was reacted with 4-aminophenyl (diphenylamine) (ATPA) or 3,5-bis(trifluoromethyl)aniline (6FA) by imide reaction. Then, Suzuki coupling reaction was carried out on these compounds with 4-(N,N-diphenylamino)-1-phenyl boronic acid (BTPA) or 3,5-bis(trifluoromethyl)phenyl boronic acid (6FBB), resulting in 3,6-bis[4-(diphenylamino)phenyl]-N,N'-bis[4-(diphenylamino) phenyl]-pyromellitimide (TPTPPI), 3,6-bis[3,5-bis(trifluoro methyl) phenyl]-N,N'-bis[3,5-bis(trifluoromethyl) phenyl]-pyro mellitimide (6F6FPI) or 3,6-bis[4-(diphenylamino)phenyl]-N,N'-bis[3,5-bistrifluoromethyl)phenyl]-pyromellitimide (6FTPPI). The imide compounds obtained were characterized by NMR, FT-IR, DSC, TGA, melting point analyzer, EA, and solubility measurements. In addition, their optical and electrical properties were evaluated by fluorescence spectroscopy, UV-vis spectroscopy, and cyclic voltammetry (CV). 6F6FPI exhibited deep blue emission (443 nm), along with high $T_m$ ($382^{\circ}C$) and relatively high $T_g$ ($148^{\circ}C$).

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.994-997
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• 2006

We have fabricated white polymeric light-emitting devices (WPLEDs) from polyfluorene-based (PFO) blue and MEH-PPV polymer blending systems. A device structure of ITO / PEDOT:PSS / Blending polymer / Blue polymer / LiF / Al was employed. This structure of double emission layers results in the significant improvement of white color shift phenomenon. A current efficiency of 4.67 cd/A ($3,900cd/m^2$, 6.4V) and a brightness value of $17,600cd/m^2$ at 9.4 V with (0.34, 0.35) CIE coordinates at 5V and (0.29, 0.29) at 9V were obtained.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 영호남 합동 학술대회 및 춘계학술대회 논문집 센서 박막 기술교육
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• pp.55-60
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• 2006

Thermally stable and solution-processable poly(N-arylcarbazole-alt-aniline) copolymers with high structural integrity were synthesized in good yields via palladium-catalyzed polycondensation of aniline with corresponding N-arylcarbazole monomers such as N-(2-ethylhexyloxyphenyl)-3,6-dibromocarbazole,bis[6-bromo-N-(2-ethylhexyloxyphenyl)carbazole-3-yl] and N-(4-(2-ethylhexyl)-3,5-dibromomethylene-phenyl) carbazole, respectively. The optical and electrochemical properties of these copolymers were measured and compared with those of poly(N-alkylcarbazole-alt-aniline) copolymer. All synthesized poly(N-arylcarbazole-alt-aniline) copolymers showed maximum UV-Vis absorption peaks at around 300 nm in THF solution, and exhibited maximum photoluminescence peaks in the blue emission range from 430 to 460 nm. It was also found that poly(N-arylcarbazole-alt-aniline) copolymers had wider band gap energy than poly(N-alkylcarbazole-alt-aniline) copolymer.

• Journal of Information Display
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• 제7권3호
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• pp.19-22
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• 2006

White polymeric light-emitting devices (WPLEDs) have been fabricated from polyfluorene-based (PFO) blue and MEH-PPV polymer blending systems. A device structure of ITO / PEDOT:PSS / Blending polymer / Blue polymer / LiF / Al was employed. This structure of double emission layers showed significant improvement of white color shift phenomenon. A current efficiency of 4.67 cd/A (3,900 $cd/m^{2}$, 6.4 V) and a brightness value of 17,600 $cd/m^{2}$ at 9.4 V with (0.34, 0.35) CIE coordinates at 5 V and (0.29, 0.29) at 9 V were achieved achieved.

• Journal of Photoscience
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• 제11권1호
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• pp.35-40
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• 2004

[Ru(2,2'-bipyridine)$_2$(4,4'-dicarboxy-2,2'-bipyridine)]$^{2+}$(RuBDc) is a very photostable probe that possesses favorable photophysical properties including long lifetime, high quantum yield, large Stokes' shift, and highly polarized emission. To evaluate the usefulness of this luminophore (RuBDc) for studying macromolecular dynamics, its intensity and anisotropy decays when conjugated to RNA bacteriophage MS2 were examined using frequency-domain fluorometry with a high-intensity, blue light-emitting diode (LED) as the modulated light source. The intensity decays were best fit by a sum of two exponentials, and the mean intensity decay time was 442.2 ns. The anisotropy decay data showed a single rotational correlation time (2334.9 ns), which is typical for a spherical molecule. The use of RuBDc enabled us to measure the rotational correlation time up to several microseconds. These results indicate that RuBDc can be useful for studying rotational diffusion of biological macromolecules.s.

• 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.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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• pp.74-75
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• 2009

White light emitting device based on a red fluorescence material (5,6,11,12)-Tetraphenylnaphthacene(Rubrene) has been fabricated. The white OLED consists of it and a blue phosphorescent material FIrPic (iridum-bis(4,6,-difluorophenylpyridinato-N,C2)-picolinate) The threshold voltage is 5.3V, and the brightness reaches $1000\;cd/m^2$ at 11V, $14.5\;mA/cm^2$. The color of the light corresponds to a CIE coordinate of (0.30, 0.38). The highest efficiency of the device can reach 9.5 cd/A or 5.5 1m/W at 6V, $0.1mA/cm^2$.

• Transactions on Electrical and Electronic Materials
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• 제12권2호
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• pp.84-87
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• 2011

We fabricated phosphorescent organic light-emitting devices with a 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) host layer. Two kinds of devices, one of ITO/TAPC/TAPC:FIrpic/TAZ/LiF/Al (device A) and one of ITO/TAPC:FIrpic/TAPC/TAZ/LiF/Al (device B), were prepared to investigate electrical and optical properties. Iridium(III) bis[(4,6-difluorophenyl)-pyridinato-N,$C^{2'}$]picolinate (FIrpic) and 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (TAZ) were used as a blue phosphorescent guest material and an electron transport layer, respectively. The TAPC layer in device B strongly contributes to whitish emission, higher driving voltage, and lower current efficiency characteristics compared with device A. The mechanisms of these electrical and optical characteristics of the devices were investigated.