• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1437-1439
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• 2007

We fabricated white organic light emitting device (WOLED) with the layered fluorescent blue material and phosphorescent green/red dye-doped materials. Addition of the non-doped phosphorescent host material between the fluorescent and phosphorescent light emitting layers provided the result of broadband white spectrum, with improved balance, higher efficiency, and lower power consumption. In our devices, there was no need of exciton-blocking layer between the each emission layer for the further confinement of the diffusion of excitons.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.351-354
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• 2006

We developed highly efficient fluorescent dopants for full-color OLEDs. For blue, green and red OLEDs, current efficiencies of 8.7cd/A, 20.5 cd/A and 11.4 cd/A at $10mA/cm^2$ were achieved, respectively. Lifetime of the blue device was estimated to be 23,000hours at an initial luminance of $1,000cd/m^2$. Moreover, long lifetime over 100,000 hours was estimated in the green and red devices. Furthermore, we obtained a three-component white OLED by using these new fluorescent materials. This white OLED shows a current efficiency of 16.1cd/A with extrapolated lifetime over 70,000 hours at $1,000cd/m^2$, and more excellent color reproducibility for full-color displays with color filters and general lighting, compared to previous fluorescent white OLEDs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.43-46
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• 2004

We demonstrated efficient white light emitting OLEDs with a single emissive layer structure, which was blue-emitting 1,4-bis[2,2-diphenylvinyl]biphenyl (DPVBi) doped with blue luminescent amino-substituted distyrylarylene amine (DSA-amine) and red luminescent [2,6-bis[2-[5-(dibutylamino) phenyl]vinyl]-4H -pyran-4-ylidene]propanedinitrile (DADB). Through the optimization of the device structure, the white light emission with full visible spectral range was obtained. Its CIE color coordinates was (0.32,0.42) at 10 $mA/cm^2$ and the external quantum efficiency, the luminance efficiency and the luminance yield were 3.7 %, 3.3 lm/W and 9.0 cd/A, respectively.

• Journal of the Korean Applied Science and Technology
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• v.39 no.5
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• pp.589-595
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• 2022

The white OLED is fabricated with the anthracene-based blue emitting material, 9-(2-naphthyl)-10-(p-tolyl)anthracene (2-NTA) in various volume-ratios of orange dopant, rubrene, which results in pure white emission with C.I.E. coordinate of ~(0.32, 0.39). The devices with <1.5% rubrene show better EL properties (efficiency) than >3% devices. Furthermore the turn-on voltage of 2-NTA WOLED (3.7 V) is lower than that of 2-NTA blue OLED (5.4 V) at the same condition. Conclusively 2-NTA with rubrene less than 1.5% (v/v) could be utilized for the pure WOLED.

• Applied Chemistry for Engineering
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• v.27 no.5
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• pp.455-466
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• 2016

Organic light-emitting diode (OLED) has drawn a lot of attention in academic and industrial fields, which has been successfully commercialized in mobile phones and TV's. In the field of lighting, unlike the existing incandescent or fluorescent lighting, OLED has distinctive qualities such as surface lighting-emission, large-area, lightweight, ultrathin, flexibility in addition to low energy use. This article introduces prominent fluorescent, phosphorescent, and luminescent materials applied to white OLED (WOLED). The understanding and systematic classification of previously studied substances are expected to be greatly helpful for the development of new luminous materials in future.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.816-819
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• 2004

White-emitting OLEDs have been prepared that provide emission close to 6500 K color temperature (D65) with exceptional stability and high efficiency. The combination of host and dopant materials offers significant improvement for full color displays, in terms of power consumption, with minimal changes in color and efficiency with current density. These features are important for fabricating RGB and RGBW full color displays using white OLEDs with color filters.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.324-325
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• 2006

In order to develop high efficiency white organic light-emitting diodes (OLEDs), OLED devices consisted of red and blue emitting layers (EMLs) were fabricated and the effect of respective layer thickness and the order of layer stacking on the luminous efficiency was evaluated Red/blue structure showed higher efficiency than blue/red, due to the higher exiton formation. In the blue layer of red/blue structure. However, the efficiency of the red/blue significantly depended on the thickness of the red layer, whereas the thickness of the blue layer was not affect so much. The optimum thickness of the red layer was 20 ${\AA}$, where the luminous and power efficiencies were 155 cd/A and 10.51 lm/W at 1000~3000$cd/m^2$ respectively and the maximum luminance was about 80,000 $cd/m^2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.100-101
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• 2008

We have developed low voltage driving white organic light emitting diode with new electron transport layer. The with light emission was realized with a yellow dopant, rubrene and blue-emitting DPVBi layer. The new electron transport layer results in very high current density at low voltage, causing a reduction of driving voltage. The device with new electron transport layer shows a brightness of 1000 cd/m2 at 4.3 V.

• Bulletin of the Korean Chemical Society
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• v.34 no.5
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• pp.1366-1370
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• 2013

A series of phosphorescent iridium(III) complexes 1-4 based on phenylpyrazole were synthesized and their photophysical properties were investigated. To evaluate their electroluminescent properties, OLED devices with the structure of ITO/NPB/mCP: 8% Iridium complexes (1-4)/TPBi/Liq/Al were fabricated. Among those, the device with 3 showed the most efficient white emission with maximum luminance of 100.6 $cd/m^2$ at 15 V, maximum luminous efficiency of 1.52 cd/A, power efficiency of 0.71 lm/W, external quantum efficiency of 0.59%, and CIE coordinates of (0.35, 0.40) at 15.0 V, respectively.

• Electrical & Electronic Materials
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• v.28 no.5
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• pp.18-23
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• 2015