• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.506-509
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• 2002

In this paper. we give pressure stimulation into organic ultra thin films and detected the induced displacement current proper ties, and then manufacture a device under the accumulation condition. In processing of a device manufacture. And electroluminescence(EL) from conjugated polymers has recently received great attention because polymer light-emitting diodes(LEDs) clealy have potential for applications such as large-area displays. The operation of polymer LEDs is based on double injection of electrons and holes from the elextrodes. followed by formation of excitons whose radiative decay results in light emission at wavelength characteristic to the material. In this paper, we fabricated the single layer EL device using $Alq_3$ as emitting material. According as turn on voltage could know about 5.5V in voltage-current characteristics and voltage rise, current could see that increase as non-linear, Current and ruminance can see that express similar relativity in voltage, and could know that ruminance is expressing current relativity.

• Macromolecular Research
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• v.15 no.3
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• pp.216-220
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• 2007

A new polyfluorene-based copolymer having 2-ethylhexyloxy-5-methoxy-l,4-phenylene as an electron donating group and 2,5-diphenyl-oxadiazole as an electron withdrawing group was synthesized by the Suzuki coupling reaction. The obtained copolymer was characterized by $^1H-NMR,\;^{13}C-NMR$, and IR-spectroscopy. The weight average molecular weight ($M_w$) of the obtained polymer was 18,600 with a polydispersity index of 1.5. The maximum photoluminescence of the solution and film of the polymer was observed at 453 nm and 456 nm, respectively. A double-layer device with the configuration, ITO/PEDOT/copolymer/Al, emitted blue light at 460 nm.

• Journal of Information Display
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• v.2 no.2
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• pp.45-51
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• 2001

Four types of conjugated polymers, poly(MEHPV-PV), poly(MEHPV-BPV), poly(MEHPV-AV) and poly(PZV-AV) were synthesized by Homer-Emmons reaction using potassium tert-butoxide. The Homer-Emmons reaction gave electroluminescent(EL) copolymers in good yield. Of the EL copolymers synthesized, poly(PZV-AV) containing phenothiazinylene vinylene and anthrylene vinylene as repeat unit exhibited red color in the light emitting diode(LED) which was very close to the NTSC standard red. Besides, double layer LED made with $Alq_3$ electron transport layer exhibited both enhanced emission intensity and efficiency compared to the single layer LED.

• Journal of the Korean Applied Science and Technology
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• v.21 no.1
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• pp.24-30
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• 2004

New electroluminescent materials based on anthracene chromophore with naphthylethenyl substituent, 9,10-bis($\alpha$-naphthylethenyl)anthracene (a-BNA), as well as four kinds of its derivatives were synthesized, and luminescent properties of these materials were investigated. Electrolumineecent(EL) emission band was discussed based on their substituent structure differences. It was found that the emission band strongly depends on the molecular structure of introduced substituent. It can be tuned from 557 nm to 591 nm by changing the substituent structures. On the other hand, the anthracene chromophore with bulky substituent possessed high melting point and they gave stable films through vacuum-sublimation. The double layer EL device of ITO/TPD/emission layer/Mg:Ag was employed, and exhibited efficient orange light originating from emitting materials. EL emission with a maximum luminance was observed in the b-BNA emitting material, : maximum luminance was about 8,060 cd $m^{-2}$ at an applied voltage of 10 V and current density of 680 $mA/cm^2$. In conclusion, the electroluminescent properties also showed good difference with their substituent structure.

• Journal of the Korean Applied Science and Technology
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• v.16 no.2
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• pp.127-133
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• 1999

New electroluminescent materials base on anthracene chromophore, [9.10-bis(${\alpha}$-naph -thylethenyl) anthracene (${\alpha}$-BNA)] were newly synthesized. The anthracene derivatives with bulky substituent possessed high melting point and they gave stable amorphous films through vacuum - sublimation methods. Three types of electroluminescent devices were fabricated with double layer and triple layer structure : ITO/TPD/emission layer/MgAg, ITO/emission layer/ OXD-7 and ITO/ TPD/ emission layer/OXD-7/MgAg, respectively. In three types of devices with the emissive layer of ${\alpha}$-BNA, efficient orange electroluminescence was observed. In the triple layer device whit a emitting layer of 20 nm thickness , maximum luminance was about 10000 cd/ $m^2$ at an applied voltage of 10v and maximum external quantum efficiency was 1.0%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.9
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• pp.750-754
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• 2011

In this research, the electric characteristic of organic light-emitting diodes(OLEDs) was studied depending on thickness of amorphous fluoropolymer(Teflon-AF) which is the material of hole injection layer to improve electric characteristic of OLEDs. Sample composition was fabricated in double layer. The basic structure was fabricated by ITO/tris(8-hydroxyquinoline) aluminum (Alq3)/Al and the 2 layer was fabricated by ITO/2,2-Bistrifluoromethyl-4,5-Difluoro-1,3-Dioxole(Teflon-AF)/tris(8-hydro xyquinoline) aluminum (Alq3)/Al. The experiment was carried with variation of thickness of Teflon-AF at 1.0, 2.0, 2.5, 3.0 nm. The result showed when Teflon-AF thickness was 2.5 nm, the electric and optical characteristic were well performed. Moreover, when it was compared with Teflon-AF without materials, it was improved 15.1 times more on luminance, 12.7 times more on luminous efficiency and 12.1 times more on external quantum efficiency. Therefore, OLEDs element with optimum hole injection layer reduced energy barrier and driving voltage, and confirmed that it improved efficiency widely.

• Journal of Information Display
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• v.9 no.2
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• pp.5-8
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• 2008

Bottom gate thin film transistors (TFTs) with microcrystalline and amorphous Si (a-Si) double active layers (DAL) were fabricated. Since the process of DAL TFTs can use that of conventional a-Si TFTs, these DAL TFT process has advantages, such as low cost, large substrate, and mass production capacity. In order to analyze the degradation characteristics in saturation region for driving TFTs of active matrix organic light emitting diode, three different dynamic stresses were applied to DAL TFTs and a-Si TFTs. The threshold voltage shift of DAL TFTs and a-Si TFTs during 10,000 second stress is 0.3V and 2V, respectively. DAL TFTs were more reliable than a-Si TFTs.

• Bulletin of the Korean Chemical Society
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• v.25 no.5
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• pp.652-656
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• 2004

A new luminescent polymer, poly{1,4-phenylene-1,2-ethenediyl-2'-[2"-(4'"-octyloxyphenyl)-(5"-yl)-1",3",4"-oxadiazole]-1,4-phenylene-1,2-ethenediyl-2,5-bis-dodecyloxy-1,4-phenylene-1,2-ethenediyl} (Oxd-PPV), was synthesized by the Heck coupling reaction. Electron withdrawing pendant, conjugated 1,3,4-oxadiazole (Oxd), is on the vinylene unit. The band gap of the polymer figured out from the UV-visible spectrum was 2.23 eV and the polymer film shows bright yellow emission maximum at 552 nm. The electroluminescence (EL) maximum of double layer structured device (ITO/PEDOT:PSS/Oxd-PPV/Al) appeared at 553 nm. Relative PL quantum yield of Oxd-PPV film is 3.6 times higher than that of MEH-PPV film. The HOMO and LUMO energy levels of Oxd-PPV figured out from the cyclic voltammogram and the UV-visible spectrum are -5.32 and -3.09 eV, respectively, so that more balanced hole and electron injection efficiency can be expected compared to MEH-PPV. A double layer EL of Oxd-PPV has an maximum efficiency of 0.15 cd/A and maximum brightness of 464 cd/$m^2$.

• Journal of Sensor Science and Technology
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• v.7 no.2
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• pp.97-102
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• 1998

Organic thin film EL devices using PPV(poly (p-phenylenevinylene)) as emitter were fabricated on various conditions and structures, their electro-optical properties were estimated. Fabricated EL devices had structures of single layer(ITO(indium tin oxide)/PPV/Mg), double layer(ITO/PVK(poly(N-vinylcarbazole))/PPV/Mg and ITO/PPV/Polymer matrix + PBD/Mg) and three layer (ITO/PVK/PPV/PS(polystyrene)+PBD(butyl-2-(4-bipheny])-5-(4-tert-butylphenyl-1,3,4-oxadiazole))/Mg), their electro-optical characteristics were compared with each other. In structure of double layer (ITO/PPV /Polymer matrix + PBD/Mg), the used polymer-matrices were PMMA(poly(methyl methacrylate), PC(polycarbonate), PS and MCH(side chain liquid crystalline homopolymer). When PS as a hole transport layer was used, the luminance characteristics on concentration of PBD was obtained. In results, current-voltage-luminance curves of fabricated devices had characteristics of tunneling effect and the device showed a stable light emitting.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1145-1148
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• 2008

The present status and trend of oxide phosphor thin-film development for thin-film electroluminescent (TFEL) device application are presented in this paper. Recently, several newly developed types of bendable or bendable see-through oxide TFEL lamps have been fabricated using the TFEL technology with a newly developed bendable ceramic sheet, glass sheet or sapphire sheet substrate, which has become available on the market. Stable operation at high temperatures was obtained in double-insulating-layer-type TFEL lamps fabricated with a $Zn_2Si_{0.6}Ge_{0.}4O_4$:Mn thin-film emitting layer forming on translucent or transparent bendable sheet substrates.