• Korean Journal of Optics and Photonics
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• v.26 no.5
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• pp.265-268
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• 2015

An inorganic electroluminescence device based on a green ZnS:(Cu,Al) phosphor was fabricated by a screen printing method. Graphene was added to the phosphor layer to increase the electroluminescence intensity. As the graphene concentration increased, the photoluminescence intensity decreased; on the other hand, the electroluminescence intensity increased, up to 0.6 wt%.

• Bulletin of the Korean Chemical Society
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• v.27 no.7
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• pp.1043-1047
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• 2006

New electroluminescence polymer, poly(5,10-dihexyl-5,10-dihydroindolo[3,2-b]indole-2,7-diyl) (PININO) was synthesized by Yamamoto conditions with Ni(0) catalyst. The full characterization of structures and properties as well as the performances of the electroluminescence devices of the new polymer are presented. The resulting polymer, which exhibits good solubility in common organic solvents, was used as the electroluminescence layer for the light-emitting diodes (LEDs) (ITO/PEDOT/polymer/Al). PININO shows turn-on voltage of 2.5 V, and electroluminescence (EL) with maximum peak at 490 nm, maximum brightness of 40 cd/$m^{2}$ at 8 V, and efficiency of 0.002 cd/A at 350 mA/$cm^{2}$.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.887-888
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• 2003

We report the electroluminescence properties of single- and multi-layer electroluminescence devices using PtOEP phosphor. Weak emission bands with peaks at 540 and 567 nm are observed in the former and latter devices, respectively, besides the well-known 648 nm PtOEP emission. The 540 nm emission increases in proportion to the third power of current density, while the 648 nm emission band increases linearly. Discussion is made on a reason for a much smaller luminance of PtOEP compared with $Ir(ppy)_{3}$ phosphor.

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1407-1409
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• 2001

• Journal of the Semiconductor & Display Technology
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• v.21 no.2
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• pp.15-18
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• 2022

The ultraviolet-C emitting praseodymium doped yttrium phosphate (YPO₄:Pr³⁺) powder was synthesized by conventional solid-state reaction. The electroluminescence device was fabricated by simple screen-printing method using the synthesized YPO₄:Pr³⁺ powder, especially, polyvinylidene fluoride as an insulating layer was applied on the printed YPO₄:Pr³⁺ powder for stable performance of the electroluminescence. The electroluminescence properties were investigated under alternating current power system of 400 Hz. The device starts to emit at 350 V, which showed the ultraviolet-C emission peaking at the 233, 245, 264, 273 nm attributed to electronic transition of the Pr³⁺ ions. The electroluminescence intensity was increased as increasing the operating voltage and the device revealed stable performance up to 600 V due to the polyvinylidene fluoride serve as a protective layer.

• Journal of the Semiconductor & Display Technology
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• v.22 no.1
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• pp.83-87
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• 2023

Y₂SiO₅ Powder based on silicon and yttrium is well known as powder phosphors due to their excellent sustainability and efficiency. A new electroluminescence device was fabricated with Y₂SiO₅:Eu³⁺ powder phosphors though a simple screen printing method. The powder-dispersed electroluminescence device consisted of the Y₂SiO₅:Eu³⁺ powder-dispersed phosphor layer and BaTiO₃-dispersed dielectric layer. The annealing temperature of the phosphor for the best powder electroluminescence performance was optimized to high temperature in ambient atmosphere though a solid-state reaction. The Eu³⁺ concentration for the best device performance was also investigated and furthermore, the thermal dependence of the electroluminescence intensity was investigated at the operating voltage at 100℃, which is the Curie temperature of the BaTiO₃ layer. And the intensity was exponentially increased with voltage and increased linearly with frequency.

• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.528-530
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• 2002

• Journal of the Korean Electrochemical Society
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• v.3 no.1
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• pp.39-43
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• 2000

The light emitting diode (LED) was fabricated from n-type porous silicon. We investigated both the current-voltage characteristics of the LED with various electrode materials and changes of electroluminescence with applied current density. Also we probed changes in electroluminescence as a function of operation time at a given current. In order to Improve the contact area between the electrode material and porous silicon layer, we deposited indium on porous silicon layer by electroplating and investigated the electric characteristics of the LED and changes of electroluminescence.

• Korean Journal of Optics and Photonics
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• v.13 no.2
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• pp.128-133
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• 2002

In a recent effort to develop polymer light-emitting diodes (LEDs) as promising flat panel display components, measurements of reliable absolute photoluminescence (PL) and electroluminescence (EL) efficiency for polymer materials are required. In this work, we performed the measurement of PL and EL efficiency of luminescent polymers using an integrating sphere technique. The external PL efficiency of MEH-PPV was estimated to be 8 ($\pm$2)% together with the value of 0.02 1m/W for the external EL efficiency. This PL efficiency is in good agreement with published values, indicating that our PL efficiency measurements are somewhat legitimate. We believe this study might contribute to the research and development of organic materials for optoelectronic devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.351-352
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• 2007

Polymers submitted to thermo/electrical stress suffer from ageing that can drastically affect their functional behaviour. Understanding the physico/chemical processes at play during ageing and defining transport regimes in which these mechanisms start to be critical is therefore a prime goal to prevent degradation and to develop new formulation or new materials with improved properties. It is thought that a way to define these critical regimes is to investigate under which conditions (in terms of stress parameters) light is generated in the material by electroluminescence (EL). This can happen through impact excitation/ionization involving hot carriers or upon bi-polar charge recombination (a definition that excludes light from partial discharges, which would sign an advanced stage in the degradation process). After a brief review of the EL phenomenology under DC, we introduce a numerical model of charge transport postulating a recombination controlled electroluminescence. The model output is critically evaluated with special emphasize on the comparison between simulated and experimental light emission. Finally, we comment some open questions and perspectives.