• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.1
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• pp.88-91
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• 2008

Electroluminescent(EL) devices based on organic thin films are considered to be one of the next generation of flat-panel displays. In this paper, we have investigated electro-luminescent(EL) characteristics of organic EL device using $Alq_3$, PBD as emitting material. Current and luminance can be seen that express a similar relativity in voltage and could know that luminance is expressing current relativity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.2
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• pp.178-182
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• 2007

Electroluminescent (EL) devices based on organic thin films are considered to be one of the next generation of flat-panel displays. In this paper, we have investigated electro-luminescent (EL) characteristics of organic EL device using $Alq_{3}$, PBD as emitting material. Current and luminance can be seen that express a similar relativity in voltage and could know that luminance is expressing current relativity.

• Proceedings of the Materials Research Society of Korea Conference
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• 2000.05a
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• pp.53-76
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• 2000

Multi-color organic electroluminescent (EL) displays have already been commercialized, and the simple extensions of present technologies on organic EL can not be a target for basic research anymore. Future prospect of research on organic electroluminescent devices are described from the view point of possible future break-through. Three aspects, perspective for further increase of device efficiencies, possibility of simplified device structures and possible use of thick organic layers, are discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.7
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• pp.539-544
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• 2010

We have synthesized new blue electroluminescent polyalkylfluorene-based copolymers [poly(F-co-Py)x:y, where x:y = 99:1 or 95:5 mole ratios] containing the hole-injecting pyrazole derivative [3,3'-(4,6-bis(octyloxy)-1,3-phenylene)bis(1,5-diphenyl-4,5-dihydro-1H-pyrazole] through Ni(0) mediated polymerization, and their electroluminescent properties were investigated. Electroluminescent (EL) devices were fabricated with ITO / PEDOT:PSS (110 nm) / copolymers or PF homopolymer (80 nm) / Ca (50 nm) / Al (200 nm) configuration. Each EL device constructed from the copolymer exhibited significantly enhanced brightness and efficiency compared with a device constructed from the PF homopolymer. The EL device constructed with poly(F-co-Py)99:1 exhibited the highest luminous efficiency and brightness (0.95 cd/A and $2,907\;cd/m^2$, respectively). The achieved luminous efficiency was an excellent result, providing almost a 4-fold improvement on the efficiency obtainable with the a PF homopolymer device. This enhanced efficiency of the copolymer devices results from their improved hole injection and more efficient charge carrier balance, which arises from the HOMO level (~5.83 eV) of the poly(F-co-Py)99:1 copolymer, which is higher than that of the PF homopolyme (~5.90 eV).

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.5
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• pp.207-210
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• 2001

In this paper, the Flexible information display was implemented uing AC powder electroluminescent device. ZnS:Cu and $BaTiO_3$ were used as a phosphor and dielectric respectively. The growth of phosphor and dielectric layer was performed with screen printing. The flexible information display in this paper was categorized as following; EL display, driving circuit, software for driving. EL spectrum and brightness was measured as the device properties.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.5
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• pp.349-353
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• 1999

In this paper, to fabricate the AC power electroluminescent device (PELD) with high brightness, new structure that constructed single emissive layer between electrodes was proposed. Dielectric and phosphor material structure that constructed single emissive layer between electrodes was proposed. Dielectric and phosphor material were BaTiO3 and ZnS:Cu respectively. Fabricated AC power EL devices were estimated by optical and electrical properties of EL spectrum, brightness, CIE coordinate system, transferred charge density and EL emission wave in time domain. With above results, we found that brightness of newly proposed AC powder EL power EL device was 2754 cd/m2 at 100V, 400 Hz and compared with conventional device structure.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1742-1744
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• 2000

Organic materials have been considered for the fabrication of practical electroluminescent(EL) devices because a large number of organic materials are known to have extremely high fluorescence quantum efficiencies in the visible spectrum. In this study, electroluminescent devices are constructed using novel organic materials PRL-401, PRL-403 as the emitting elements. The devices have a triple-layer structure of organic thin films, prepared by vacuum vapor deposition. Greenish yellow electroluminescent emission is observed. The maximum luminances are over 1000 $cd/m^2$ and the turn-on voltages are about 13 V.

• 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.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.914-916
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• 2003

Novel red organic electroluminescent (EL) dye, RED was developed for an application to the emission layer of EL device. Well known red material DCJTB was also used for comparison. Two kinds of devices were fablicated; one is ITO/ CuPc / TPD / 0.5% RED-1 in Alq3/ Alq3/ Li20/ Al and the other is ITO/ CuPc /TPD / 0.5% DCJTB in Alq3/Alq3/ Li20 / Al. External quantum efficiency of the EL device with RED was two times higher than that of the device with DCJTB. The maximum EL peak was detected at 635nm in the RED EL device.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.4
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• pp.332-337
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• 2002

The applicability of models based on fractal geometry to characterize the surface of the EL devices was investigated. Insulating layer and phosphor layer of EL devices were deposited on ITO glass using e-beam method. The images of phosphor layer by scanning electron microscope(SEM) were transformed to binary coded data. The relations between fractal geometry and electrical characteristics of EL devices were investigated. When the fractal dimension of $Cas:EuF_3$ EL device was 1.82 and its grain boundary area was 19%, the brightness of $Cas:EuF_3$ EL device was 261 cd/$\textrm{m}^2$.