• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.871-877
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• 1998

Electroluminescent(EL) devices based on organic materials have been of great interest due to their possible applications for large-area flat-panel displays, where they are attractive because of their capability of multicolor emission, and low operation voltage. In this study, glass substrate/ITO/Eu(TTA)$_3$(phen)/Al, glass substrate/ITO/Eu(TTA)$_3$(phen)/Al and glass substrate/ITO/Eu(TTA)$_3$(phen)/AlQ$_3$/Al structures were fabricated by vacuum evaporation method, where aromatic diamine(TPD) was used as a hole transporting material, Eu(TTA)$_3$(phen) as an emitting material, and Tris(8-hydroxyquinoline) aluminu-m(AlQ$_3$) as an electron transporting layer. Electrolumescent(EL) and I-V characteristics of Eu(TTA)$_3$-(-phen) were investigated. These structures show the red EL spectra, which are almost the same at the PL spectrum of Eu(TTA)$_3$(phen). I-V characteristics of this structure show that turn-on voltage was 9V and current density was 0.01A/㎤ at a operation voltage of 9V. Electrical transporting phenomena of these structures were explained using the trapped-charge-limited current model with I-V characteristics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.317-320
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• 1998

Electroluminescent(EL) devices based on organic materials have been of great interest due to their possible applications for large-area flat-panel displays, where they are attractive because of their capability of multicolor emission, and low operation voltage. In this study, glass substrate/ITO/Eu(TTA)$_3$(Phen)/Al(A), glass substrate/ITO/TPD/Eu(TTA)$_3$(phen)/Al(B) aNd glass substrate/ITO/TPD/Eu(TTA)$_3$(Phen)/A1Q$_3$/Al (C) structures were fabricated by vacuum evaporation method, where aromatic diamine(TPD) was used as a hole transporting material, Eu(TTA)$_3$(phen) as an emitting material, and tris(8-hydroxyquinoline) Aluminum (AlQ$_3$) as an electron transporting layer. Etectroluminescent(EL) and I-V characteristics of Eu(TTA)$_3$(phen) with a various thickness were investigated. This structure shows the red EL spectrum, which is almost the same as the PL spectrum of Eu(TTA)$_3$(phen). I-V characteristics of this structure show that turn-on voltage was 9V and current density was 0.01A/㎤ at a dc operation voltage of 9V. Electrical transporting phenomena of these structures was explained using the trapped-charge-limited current model with I-V characteristics.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1705-1707
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• 2000

유기 전기발광 디스플레이 (Electroluminescence Display; ELD)는 저전압 구동, 자기발광, 경량박형, 광시야각, 빠른 응답속도 등의 장점으로 차세대 디스플레이의 후보로서 주목받고 있다. Eu complex는 610 nm 부근에서 예리한 스펙트럼의 대역폭을 가지며 붉은색의 강한 형광을 나타내는 유기화합물로 잘 알려져, 있다. 새로이 합성한 란탄계 금속착물인 $Eu(TTA)_{3}TPPO$를 발광층으로 사용하여 적색 발광의 효율을 높이기 위해 소자를 제작하였고, 이 때 구동 전압은 9 V이고 18 V에서 가장 밝은 38cd/$m^2$의 휘도를 나타내었으며 전류밀도는 20mA/$cm^2$ 이었다. 제작된 소자의 EL 스펙트럼은 615 nm로 PL 스펙트럼과 동일하게 예리한 최대 피크를 나타내었고, 순환 전압전류법을 이용하여 각 유기 물질들의 에너지 준위를 알 수 있었으며, 각각의 소자들의 에너지 밴드 다이어그램을 통하여 전기적 특성을 분석하였다.

• Applied Science and Convergence Technology
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• v.26 no.2
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• pp.26-29
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• 2017

Thin films of europium-doped yttrium oxide ($Y_2O_3$:Eu) were prepared on Si (100) substrates by using a radio frequency (RF) magnetron sputtering. After the deposition, the films were annealed at $1000^{\circ}C$ in an air ambient for 1 hour. X-ray diffraction analysis revealed that the $Y_2O_3$:Eu films had a polycrystalline cubic ${\alpha}-Y_2O_3$ structure. The as-deposited films showed no photoluminescence (PL), which was due to poor crystalline quality of the films. The crystallinity of the $Y_2O_3$:Eu films was significantly improved by annealing. The strong red PL emission was observed from the annealed $Y_2O_3$:Eu films and the highest intensity peak was centered at around 613 nm. This emission peak originated from the $^5D_0{\rightarrow}^7F_2$ transition of the trivalent Eu ions occupying the $C_2$ sites in the cubic ${\alpha}-Y_2O_3$ lattice. The broad PL excitation band was observed at wavelengths below 280 nm, which was attributed to the charge transfer transition of the trivalent Eu ion.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.645-652
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• 2019

Phosphor with phosphorus doped with rare earth ions was investigated by searching Sr and Eu phosphors suitable for substitution of Eu ions with similar ionic radius to polyphosphate host. The $NaSr(PO_3)_3$ phosphor was synthesized by the solid state method and the $NaSr(PO_3)_3:Eu^{2+}$ phosphor was prepared by the carbon thermal reduction method. Both of the phosphors were identified by X - ray diffraction. The excitation and emission spectra of $NaSr(PO_3)_3:Eu^{3+}$ increased fluorescence intensity and intensity quenching with increasing $Eu^{3+}$ concentration. The higher the $Eu^{3+}$ concentration in the emission spectrum, the higher the local symmetry of $Eu^{3+}$ environment. The mechanism of concentration quenching, in which fluorescence decreases due to the energy transfer between $Eu^{2+}$ ions with the closest critical distance between $Eu^{2+}$ ions with increasing $Eu^{2+}$ ion concentration, was confirmed in the emission spectrum of $NaSr(PO_3)_3:Eu^{2+}$ concentration. It is possible to change the fluorescent region through the post-processing of single rare earth ion added phosphors, and it is possible to change the fluorescence by applying the energy transfer and concentration quenching mechanism according to the local symmetry of $Eu^{3+}$ will be used for high phosphor development.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.769-772
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• 2004

We report on the developed fabrication method of lanthanide-doped xerogel/porous anodic alumina structures for an image formation via the aluminum anodization, the sol-gel synthesis, and the photolithography process. The structures of europium- or terbium-doped xerogel/porous anodic alumina are also considered in view of application in electroluminescent devices.

• Journal of Powder Materials
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• v.20 no.5
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• pp.382-387
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• 2013

• Proceedings of the Optical Society of Korea Conference
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• 2005.02a
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• pp.26-27
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• 2005

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.101-101
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• 2007

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.103-103
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• 2007