• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1280-1283
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• 2005

A novel zinc complex, Zn(phen)q, was synthesized from 1,10-phenanthroline (phen) and 8-hydroxyquinoline (q) as organic ligands and its electroluminescent (EL) properties were characterized. The structure of Zn(phen)q was elucidated by FT-IR, UV-Vis and XPS. The complex Zn(phen)q showed thermal stability up to $300^{\circ}C$ under nitrogen flow, which was measured by TGA and DSC. The photoluminescence (PL) of the Zn(phen)q was measured from the THF solution and the solid film on quartz substrate. The PL emission of Zn(phen)q exhibited green light centered at about 505nm. The EL devices were fabricated by the vacuum deposition. The EL devices having the structure of ITO/a-NPD/Zn(phen)q/Li:Al were studied, where 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl(a-NPD) used as a hole transport layer(HTL). a-NPD has high Tg of $96^{\circ}C$ and thus makes the device thermally stable. The EL emission of Zn(phen)q exhibited also green light centered at 532nm.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.396.2-396.2
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• 2014

백색 유기발광소자는 전색 디스플레이, 조명으로서의 잠재적인 특성으로 차세대 디스플레이 소자 기술로 많은 주목을 받고 있다. 백색 유기발광소자는 주로 R-G-B 영역의 다양한 발광층을 적층하여 제작한다. 하지만 여러 발광층을 적층해야하기 때문에 제작할 때 공정 과정이 복잡해지고, 높은 생산단가를 가지게 된다. 이런 문제를 해결하기 위해 형광체를 이용한 백색 유기발광소자의 연구가 진행되고 있지만, 아직 색순도와 색좌표에 대한 많은 연구가 미흡한 상태이다. 본 연구에서는 무기물 형광체를 활용하여 백색 유기발광소자의 전기적 특성과 광학적 특성을 관찰하였고, 광원으로 사용된 청색 유기발광소자에 녹색과 적색의 무기물 형광체를 결합하는 방법으로 백색 유기발광소자를 제작하였다. 광원으로 사용한 청색 유기발광 소자는 투명전극으로 ITO를 사용하였고, 정공 수송층으로 N,N'-bis-(1-naphthyl)-N,N'-diphenylbenzidine, 발광층으로 4,4-bis(2,2-diphenylethen-1-yl)biphenyl, 정공 저지 층과 전자 수송 층은 각각 bathocuproine 과 4,7-diphenyl-1,10-phenanthroline 을 사용 하였다. 전자 주입 층으로는 lithium quinolate를 사용하였으며 음극으로는 Al을 사용하였다. 색 변환 층으로 사용된 유기물 형광체는 sol-gel 방법으로 제작된 녹색 형광체 Y3Al5O12:Ce, 적색 형광체 Ca2AiO19:Mn 을 사용하였다. Sol-gel 방법으로 제작된 형광체는 X선 회절 분석기를 통해 JCPDS cards를 확인하였고, 형광체의 녹색과 적색의 혼합비율에 따른 색좌표를 확인하여 백색 유기발광소자를 제작 하였다.

• Journal of Microbiology
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• v.43 no.3
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• pp.237-243
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• 2005

The protease purified from Bacillus cereus JH108 has the function of leucine specific endopeptidase. When measured by hydrolysis of synthetic substrate (N-succinyl-Ala-Ala-Pro-Leu-p-nitroanilide), the enzyme activity exhibited optimal activity at pH 9.0, $60^{\circ}C$. The endopeptidase activity was stimulated by $Ca^{++},\;Co^{++},\;Mn^{++},\;Mg^{++},\;and\;Ni^{++}$, and was inhibited by metal chelating agents such as EDTA, 1,10-phenanthroline, and EGTA. Addition of serine protease inhibitor, PMSF, resulted in the elimination of the activity. The endopeptidase activity was fully recovered from the inhibition of EDTA by the addition of 1 mM $Ca^{++}$, and was partially restored by $Co^{++}\;and\;Mn^{++}$, indicating that the enzyme was stabilized and activated by divalent cations and has a serine residue at the active site. Addition of $Ca^{++}$ increased the pH and heat stability of endopeptidase activity. These results show that endopeptidase requires calcium ions for activity and/or stability. A Lineweaver-Burk plot analysis indicated that the $K_m$ value of endopeptidase is 0.315 mM and $V_{max}$ is 0.222 ) is $0.222\;{\mu}mol$ of N-succinyl-Ala-Ala-Pro-Leu-p-nitroanilide per min. Bestatin was shown to act as a competitive inhibitor to the endopeptidase activity.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.780-783
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• 2002

We report very efficient white OLEDs consisting of a blue-emitting 4,4'bis[N-(1-napthyl)-N-phenyl-amino]-biphenyl (${\alpha}$-NPD), a hole-blocking layer of 2,9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP) doped with red fluorescent dye of 4-dicyanomethylene-2-methyl-6-[2-(2,3,6,7-tetrahydro- 1H, 5H-benzo[i,j]quinolizin-8-yl) vinyl]-4H-pyran) (DCM2), and green-emitting tris(8-hydroxyquinoline) aluminum ($Alq_3$). The device with the structure of ITO/${\alpha}$-NPD (50 nm)/BCP:DCM2 (0.8 %, 4 nm)/$Alq_3$ (50 nm)/LiF (0.5 nm)/Al shows a white emission with the CIE coordinates (0.329, 0.333). The maximum luminance of 20,800 cd/$m^2$ is obtained at 15.4 V. The power efficiency is 2.6lm/W and the external quantum efficiency is 2.1 % at a luminance of 100 cd/$m^2$ at the bias voltage of 6 V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.313-314
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• 2005

Organic light emitting diodes(OLEDs) are widely used as one of the information display techniques. We synthesized (1,10-phenanthroline)- (8-hydroxyquinoline) [Zn(Phen)q]. We studied the improvement of OLEDs properties using Zn(phen)q. The Ionization Potential(IP) and the Electron Affinity(EA) of Zn(phen)q investigated using cyclic voltammetry(CV). The IP, EA and Eg were 7.leV, 3.4eV and 3.7eV, respectively. The PL spectrum of Zn(phen)q was yellowish green as the wavelength of 535nm. In this study, we used Zn(phen)q as electron transporting layer(ETL) inserted between emitting layer(EML) and cathode. As a result, Zn(phen)q is useful as electron transporting layer to enhance the performance of OLEDs.

• Food Science and Biotechnology
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• v.14 no.6
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• pp.832-835
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• 2005

Inhibitory activity of active compound isolated from Ruta chalepensis leaf was examined against alcohol dehydrogenase and, upon comparison to those of four commercially available compounds (quinoline, quinoline-3-carboxaldehyde, quinoline-3-carboxylic acid, and quinoline-4-carboxylic acid) and 1,10-phenanthroline as alcohol dehydrogenase inhibitor, was characterized as quinoline-4-caboxaldehyde by spectral analyses. Inhibitory effects ($IC_{50}$) of quinoline-4-caboxaldehyde and quinoline derivatives varied depending on chemicals and concentrations used. The $IC_{50}$ values of quinoline-4-carboxaldehyde, quinoline-3-carboxaldehyde, quinoline, quinoline-3-carboxylic acid, and quinoline-4-carboxylic acid were 0.04, 0.3, 0.8, >1, and >1 mg/mL, respectively. These results suggest inhibitory action of quinoline-4-carboxaldehyde against alcohol dehydrogenase as prospective therapeutics for treatment of alcoholic liver diseases such as alcohol hepatitis and cirrhosis resulting from chronic alcohol abuse.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.473-473
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• 2012

유기발광소자는 낮은 구동전압, 빠른 응답속도, 넓은 시야각 등의 장점으로 소형 디스플레이에 사용되며 차세대 조명으로 관심을 받고 있다. 고효율의 유기발광소자를 제작하기 위해서 다양한 유기 인광물질 합성 및 연구가 진행되고 있으며, 다양한 호스트 물질을 사용하여 전자와 정공의 주입을 향상하여 고효율의 인광 유기발광소자를 제작하였다. 본 논문에서는 발광층에 N,N'-dicarbazolyl-3,5-benzene (mCP)와 1,3,5-tri(phenyl-2-benzimidazole)-benzene (TPBi)를 혼합 호스트로 사용하였으며 tris(2-phenylpyridine)iridium ($Ir(ppy)_3$)청색 인광물질을 도핑하여 고효율의 인광 유기발광소자를 제작하였다. 유기발광소자의 발광층에 단일 호스트와 혼합 호스트의 전기적 및 광학적 특성을 비교 분석하여 전자 및 정공 수송 메커니즘을 규명하였다. 혼합 호스트 TPBi의 lowest unoccupied molecular orbital (LUMO) 준위와 엑시톤 저지층 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP)의 LUMO 준위와 비슷하여 전자의 주입을 향상시키는 역할을 하며, 다른 혼합 호스트 mCP는 highest occupied molecular orbital (HOMO)와 정공수송층 N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB)의 HOMO와 비슷하여 정공의 주입을 향상시키는 역할을 하여, $Ir(ppy)_3$에 전자와 정공의 주입이 향상되어 고 효율의 인광 유기발광소자를 제작할 수 있었다. 이와 같은 실험결과는 인광 유기발광소자의 호스트 물질에 따른 전하주입 메커니즘을 설명 하였으며 고효율의 인광 유기발광소자 제작에 도움을 줄 것이다.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.474-474
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• 2012

유기발광소자는 다른 디스플레이에 비해 높은 명암비와 색재현성의 장점을 갖는 차세대 디스플레이로서, 얇은 박막 특성을 가지고 있기때문에 모바일용 디스플레이 기술로 많이 사용되고 있다. 하지만 낮은 발광효율, 높은 구동전압 및 전압에 따른 색좌표 변화의 문제점을 가지고 있어 이를 극복하기 위한 많은 연구가 진행되고 있다. 유기 발광 소자의 발광효율을 높이며 구동 전압을 낮추기 위해 호스트물질에 다양한 도펀트를 도핑하고 있다. 높은 발광효율을 가지는 도펀트인 5,6,11,12-tetraphenylnaphthacene (rubrene)을 사용한 유기발광소자는 rubrene의 안정된 분자 에너지 레벨로 인해 전자들이 포획되는 현상이 나타나 효율이 감소되는 원인이 규명되지 않았다. 본 연구에서는 rubrene을 발광층으로 사용하여, 전공수송층인 N,N_-bis-(1-naphthyl)-N,N_-diphenyl-1,1-biphenyl-4,4-diamine (NPB)의 두께에 따른 I-V 변화와 전계발광 스펙트럼를 분석하여 두께에 따른 rubrene의 전자 포획를 관찰하였다. rubrene보다 큰 lowest unoccupied molecular orbital 에너지를 갖는 NPB와 에너지장벽으로 낮은 highest occupied molecular orbital 에너지를 갖는 4,7-diphenyl-1,10-phenanthroline을 각각 교차되게 적층한 유기발광소자의 I-V 변화와 전자 전공 재결합층의 위치변화에 따른 전계발광 스펙트럼을 비교 분석하였다. 이 결과는 발광층 내부의 rubrene의 상대적인 위치와 에너지장벽과의 상관관계에 따른 전자 포획 메커니즘을 이해하는데 도움 줄 것이다.

• Journal of Microbiology
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• v.41 no.2
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• pp.73-77
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• 2003

Four proteolytic bacteria were isolated and identified from a rotating biological contactor based on Bacillus. The four isolates, Ni 26, 36, 39 and 49 were identified as B. vallismortis, B. subtilis, Aeromonas hydrophila and B. amyioliquefaciens, respectively, based on their biochemical properties and 16S rDNA sequence analyses. The optimal proteolytic activity was observed in the temperature and pH ranges of 40-70$^{\circ}C$ and 8.0-8.5, respectively. The proteolytic activities of all the isolates were partially inhibited by phenylmethylsulfonylfluoride (PMSF), and the isolates Ni 26, Ni 39 and Ni 49 were inhibited by the metalloprotease inhibitor, 1,10-phenanthroline. Zymographic analyses of the culture supernatants revealed the presence of at least two pretenses in all isolates.

• 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.