• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2001년도 International Meeting on Information Display
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• pp.209-212
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• 2001

We report the synthesis and characterization of new alkoxy substituted spirobifluorene derivatives. The spiro compounds having alkoxy hydrocarbon chains were readily soluble in common organic solvents, having improved film-forming properties and had a significantly reduced tendency to crystallize, resulting in increasing their service lifetime. The results of DSC showed that it was amorphous. The optical and electroluminescent spectra were characterized. Electroluminescence (EL) properties of three-layer light emitting diodes (LED) of $ITO/TPD/spirobifluorene/Alq_3/LiF/Al$ as the active layer were characterized. Blue emission peaking of the EL spectrum of the three-layer device at 402 nm and a luminance of 3,125 $cd/m^2$ were achieved at a drive voltage 12.8 V. The luminous efficiency was obtained to be 1.7 lm/W. The color coordinate in CIE chromaticity is (0.16, 0.09), which is in a pure blue region. The external quantum efficiency was obtained to be 2.0%. The results indicate that the spirobifluorene compounds having alkoxy hydrocarbon chains are strongly potential blue emitters for LED applications.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.493-496
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• 2009

We report the EL property of blue and blue-violet emitting materials with anthracene moiety as well as a new core structure containing indenopyrazine. Non-doped device using one of indenopyrazine core derivatives was found to exhibit excellent blue-violet color purity of (0.173, 0.063), and narrow emission band of 42nm FWHM. One of anthracene core derivatives with bulky side group also exhibits excellent color coordinates (0.156, 0.088) and an external quantum efficiency of 7.18%.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.249-252
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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 display-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 light-emitting multilayer organic electroluminescence devices were fabricated vsing Poly (9-vinylcarbaEole) (PVK) and 2- (4-tert-butylphenyl)-5-(4$^{#}$-bis-phenyl) 1,3,4-oxadiazole (PBO) as hole trasport and electron transport material, respectively, where trim(8-hyd roxyquinolinate) aluminum (Al $q_3$) was used as a luminescenct material. A cell structure of glass sub- strate/indume-tin-oxide(ITO)/PCK/Al $q_3$/PBD/Mg:In was employed. Blue emission peak at 510nm was observed with this cell structure.e.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.1057-1059
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• 2003

New polyfluorene derivatives, poly[9,9-bis(4' n-octyloxyphenyl)] fluorene (PAPF-8) and poly[9,9-bis(4'-(2",7"-dimethylocyloxy)phenyl)] fluorene (PAPF-10) were synthesized from the monomers, 2,7-dibromo-9,9-bis[4' (2"-ethylhexyloxy)benzene] fluorene and 2,7-dibromo-9,9-bis[4' (2", 7"-dimethyloctyloxybenzene)] fluorene through the Ni(0) mediated polymerization. The copolymers were characterized using FT-IR spectroscopy, UV-vis spectroscopy, TGA, photoluminescence (PL) & electroluminescence (EL) spectroscopy, elementa analysis, and molecular weight studies. The synthesized POPF-8 and POPF-10 showed a pure blue emission without any spectral change upon thermal annealing and EL device operation.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2287-2294
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• 2012

Deep blue fluorescent host materials based on a novel spiro[benzo[c]fluorene-7,9'-fluorene] core structure with side aromatic wings in the 5- and 9-positions, namely, 5,9-di(naphthalen-2-yl)spiro[benzo[c]fluorene-7,9'-fluorene] (DN-SBFF), 5,9-bis(4-t-butylphenyl)spiro[benzo[c]fluorene-7,9'-fluorene] (BP-SBFF), and 5,9-bis(4-fluorophenyl)spiro[benzo[c]fluorene-7,9'-fluorene] (FP-SBFF), were designed and successfully prepared using the Suzuki reaction. The physical properties of these materials and their EL characteristics as blue host materials doped with N,N,N',N'-tetraphenylspiro[benzo[c]fluorene-7,9'-fluorene]-5,9-diamine (TPA-SBFF) were investigated. The device used comprised ITO/N,N'-diphenyl-N,N'-bis[4-(phenyl-m-tolyl-amino)phenyl]-biphenyl-4,4'-diamine (DNTPD)/N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine (NPB)/(FP-SBFF):dopant x%/tris(8-hydroxyquinoline)aluminum ($Alq_3$)/LiF. The device obtained using FP-SBFF doped with TPA-SBFF showed high color purity (0.13, 0.18) and an efficiency of 6.61 cd/A at 7 V.

• Bulletin of the Korean Chemical Society
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• 제35권10호
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• pp.3041-3046
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• 2014

Blue emitting materials, 9,10-bis-biphenyl-4-yl-anthracene (AC-P), 9,10-bis-[1,1';4',1"]terphenyl-4-yl-anthracene (AC-DP), and 9,10-bis[3",5"-deiphenyltriphenyl-4'-yl]anthracene (AC-TP) were synthesized through boration and Suzuki aryl-aryl coupling reaction. EL performance of blue light-emitters was optimized and improved by varying the chemical structures of the side groups. In the thin film state, the three materials exhibit $PL_{max}$ values in the range of 442-456 nm. EL device with the synthesized compounds in the following configuration was fabricated: ITO/4,4',4"-tris(N-(2-naphthyl)-N-phenylamino)triphenylamine (2-TNATA) 60nm/N,N'-bis (naphthalene-1-yl)-N,N'-bis(phenyl)benzidine (NPB) 15nm/synthesized blue emitting materials (30nm)/1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl (TPBi) 20nm/LiF 1nm/Al 200nm. The current efficiency and C.I.E. value of AC-TP were 3.87 cd/A and (0.15, 0.12). A bulky and non-planar side group helps to prevent ${\pi}-{\pi}^*$ stacking interaction, which should lead to the formation of more reliable amorphous film. This is expected to have a positive effect on the high efficiency of the operating OLED device.

• Journal of Advanced Marine Engineering and Technology
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• 제30권4호
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• pp.514-519
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• 2006

SrS:Cu, Cl thin films have been grown by the hot wall technique with S furnace placed on the outside of the growth chamber in order to investigate the crystallographic and optical characteristics. The films have a good crystallinity independent of CuCl wall temperature and PL characteristics showed a peak assigned by the transition form $3d^94s^1\;(^3Eg)$ to $3d^{10}\;(^1A_{1g})$ of $Cu^+$ center. It has also been found that. from the PLE spectra, $Cu^+$ luminescent centers are doped in the host materials. The EL emission from SrS:Cu-based device showed a greenish-blue but shifted to short wavelength compared to SrS:Ce-based EL. The device was obtained the maximum luminance of $110cd/m^2$ and the maximum luminous efficiency of $0.1\;lm/W$ at $V_{40}$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.286-290
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• 1999

Electroluminescence is occurred when phosphor is located in electric field. In this paper, we made powder electroluminescent device (PELD) with structured ITO film/Phosphor/Insulator/Silver paste. The transparent electrode was ITO film and green(2704-01), orange(2702-02) and blue-green(2703-01) were used as phosphor. The insulator was BaTiO$_3$ and $Y_2$O$_3$, back electrode was silver paste. To investigate electrical and optical properties of PELDs, EL spectrum, Brightness, Transferred charge density using Sawyer-Tower\`s circuit was measured.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.582-585
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• 1999

Electroluminescence is occurred when phosphor is located in electric field. In this paper, we made powder electroluminescent device (PELD) with structured ITO film/Phosphor/Insulator/Silver paste. The transparent electrode was ITO film and green(2704-01) and orange(2702-02) and blue-preen(2703-01) were used as phosphor. The insulator was BaTiO$_3$ and $Y_2$O$_3$, bark electrode was silver paste. To investigate electrical and optical properties of PELDs, EL spectrum, Brightness . Transferred charge density using Sawyer-Towers circuit was measured.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.1050-1053
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• 2004

Many organic materials have been synthesized and extended efforts have been made to obtain high performance electroluminescence(EL) devices, since the first report of the light-emitting diodes based on Alq3. BECCP[bis(3-N-ethylcarbazolyl)cyanoterephthalidene] is a new luminescent material having cyano as an electron acceptor part and carbazole moiety as an electron donor part. The BECCP material shows blue PL and EL spectra of the device at about 480nm and in the ITO/BECCP/Al device shows typical rectifying diode characteristics. We have introduced Alq3 between the electrode and BECCP, and obtained more intensive rectifying diode characteristics in forward and reverse bias.