• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.416-417
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• 2006

Organic light emitting diodes (OLEDs) show a lot of advantages for display purposes. Because OLEDs provide white light emission with a high efficiency and stability, it is desirable to apply OLEDs as an illumination light source and back light in LCD displays. We synthesized new emissive materials, namely [2-(2-hydroxyphenyl)benzoxazole] ($Zn(HPB)_2$) and [(2-(2-hydroxyphenyl)benzoxazole)(8-hydoxyquinoline)] (Zn(HPB)q), which have a low molecular compound and thermal stability. We studied white OLEDs using $Zn(HPB)_2$ and Zn(HPB)q. The fundamental structures of the white OLEDs were ITO/PEDOT:PSS (23 nm)/NPB (40 nm)/$Zn(HPB)_2$ (40 nm)/Zn(HPB)q (20 nm)/$Alq_3$ (10 nm)/LiAl (120 nm). As a result, we obtained a maximum luminance of $15325\;cd/m^2$ at a current density of $997\;mA/cm^2$. The CIE(Commission International de l'Eclairage) coordinates are (0.28, 0.35) at an applied voltage of 9.75 V.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.927-931
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• 2010

Recently, high luminance and high efficiency were realized in OLED with multilayer structure including emitting materials such as metal-chelate complexes. We synthesized a new luminescent material, namely, [2-(2-hydroxyphenyl)quinoline] (Zn(HPB)q) which has low molecular compound and emitted in yellowish green region. The ionization potential(IP) and electron affinity(EA) of Zn(HPB)q were measured by cyclic-voltammetry(CV). As a result, IP and EA of Zn(HPB)q were calculated 6.8 eV and 3.5 eV, respectively. We fabricated the devices and observed the possibility of Zn(HPB)q as electron transporting layer. We have obtained an improvement of luminance and decrease of turn-on voltage using Zn(HPB)q as electron transporting layer.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.2018-2019
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• 2007

Organic light emitting diodes (OLEDs) show a lot of advantages for display purposes. Because OLEDs provide white light emission with a high efficiency and stability, it is desirable to apply OLEDs as an illumination light source and back light in LCD displays. We synthesized new emissive materials, namely $Zn(HPB)_2$ and Zn(HPB)q, which have a low molecular compound and thermal stability. We studied white OLEDs using $Zn(HPB)_2$ and Zn(HPB)q. The fundamental structures of the white OLEDs were ITO / NPB (40 nm) / $Zn(HPB)_2$ (40 nm) / Zn(HPB)q (20 nm) / LiAl (120nm). As a result, we obtained a maximum luminance of $15325cd/m^2$ at a current density of $997\;mA/cm^2$. The CIE (Commission International de l'Eclairage) coordinates are (0.28, 0.35) at an applied voltage of 9.75 V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.05a
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• pp.23-24
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• 2006

We have synthesized electroluminescence materials. including [2-(2-hydroxyphenyl)benzoxazole] (Zn(HPB)$_2$), [(2-(2-hydroxyphenyl)benzoxazole)(8-hydoxyquinoline)] (Zn(HPB)q) and [(1, 10-phenanthroline)(8-hydroxyquinoline)] Zn(phen)q. The ionization potential (IP) and electron affinity (EA) of each Zn-complex was measured using cyclic-voltammetry (C-V). Basing on the consideration of matched in the energy levels of the materials. We investigated the electron transporting properties of Zn(HPB)q and Zn(phen)q compared with $Alq_3$, and also we investigated the hole blocking properties of Zn(HPB)$_2$, compared with BCP. As a result, we used Zn-complex to enhance the performance of OLED. Therefore, we demonstrate that Zn(HPB)q and Zn(phen)q are useful as an electron transporting material. Zn(HPB)$_2$ is also good a hole blocking material.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1890-1892
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• 2005

Recently, high luminance and high efficiency were realized in OLEDs with multilayer structure including emitting materials such as metal-chelate complexes. New luminescent materials, [2- (2-hydroxyphenyl)-quinoline] (Zn(HPB)q), [(1,10-phenanthroline)- (8-hydroxyquinoline)] Zn(Phen)q was synthesized. Zn-Complexes have low molecular compound and thermal stability. The ionization potential(IP) and electron affinity(EA) of Zn-complexes were measured by cyclic-voltammetry(CV). The fundamental structure of the OLEDs was $ITO/{\alpha}$-NPD/Zn-Complex/Al and then we made device structure rightly in energy band gap. We using Zn(Phen)q as emitting layer and Zn(HPB)q as electron transport layer. We measured current density-voltage, luminance-voltage characteristics.

• Proceedings of the KIEE Conference
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• 2008.05a
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• pp.167-168
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• 2008

Organic light emitting diodes (OLEDs) show a lot of advantages for display purposes. Because OLEDs provide white light emission with a high efficiency and stability, it is desirable to apply OLEDs as an illumination light source and back light in LCD displays. We synthesized new emissive materials, namely $Zn(HPB)_2$ and Zn(HPB)q, which have a low molecular compound and thermal stability. We studied white OLEDs using $Zn(HPB)_2$ and $Zn(PQ)_2$. The fundamental structures of the white OLEDs were ITO / NPB (40 nm) / $Zn(HPB)_2$ (40 nm) / $Zn(PQ)_2$ (20 nm) / LiAl (120 nm). As a result, we obtained a maximum luminance of $4200cd/m^2$ at a current density of $440mA/cm^2$. The CIE (Commission International de l'Eclairage) coordinates are (0.319, 0.338) at an applied voltage of 10 V.