Dong Chul Choo

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The optical properties of white organic light-emitting devices (WOLEDs) fabricated utilizing a CaAl12O19:Mn and Zn2SiO4:Mn phosphor layer were investigated. X-ray diffraction patterns for CaAl12O19:Mn and Zn2SiO4:Mn phosphors showed that Mn ions in the CaAl12O19:Mn phosphors were completely substituted into Ca ions and that Mn ions in the Zn2SiO4:Mn(More)
The luminance mechanisms of the white organic light-emitting devices (WOLEDs) with a charge generation layer (CGL) consisting of a tungsten oxide layer and a 5,6,11,12-tetraphenyltetracene (rubrene) doped N,N',-bis-(1-naphthyl)-N,N'-diphenyl1-1'-biphenyl-4,4'-diamine (NPB) layer were investigated. Current densities and luminances of the WOLEDs increased(More)
Flexible white organic light-emitting devices (WOLEDs) with an emitting layer consisting of a porous red poly(2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylenevinylene) (MEH-PPV) polymer layer and a blue 4,4'-bis(2,2'-diphenylvinyl)-1,1'-biphenyl (DPVBi) small molecular layer were fabricated on polyethylene terephthalate substrates. The current density of the(More)
Poly(methyl methacrylate) (PMMA) substrates containing silver nanowires (Ag NWs) were fabricated by using a transfer method. Ag NWs with a length of 20 μm and a width of 80 nm were synthesized by using a modified polyol process. Ag NW electrodes with a high surface roughness value on glass substrates were significantly improved by using both a transfer(More)
Enhancement mechanisms of the luminance efficiency in green organic light-emitting devices (OLEDs) fabricated utilizing a cesium fluoride (CsF)/fullerene (C60) heterostructure acting as an electron injection layer (EIL) were investigated. The luminance efficiencies as functions of the current density showed that the luminance efficiency in the green OLEDs(More)
The electrical and the optical properties of white organic light emitting devices (OLEDs) utilizing trapping layers inserted into both an electron transport layer (ETL) and an emitting layer (EML) were investigated. The current density of OLEDs with an ETL containing a 5,6,11,12-tetraphenylnaphthacene (rubrene) layer was slightly smaller than those of other(More)
White organic light-emitting devices (WOLEDs) were fabricated utilizing a mixed color-conversion layer consisting of CaAl12O19:Mn and Zn2SiO4:Mn phosphors. The ratio between the CaAl12O19:Mn and the Zn2SiO4:Mn phosphor determined the rate of the red and the green lights. The color rendering index was improved by using a mixed color-conversion phosphor layer.
The electrical and the optical properties in green organic light-emitting devices (OLEDs) fabricated utilizing tris(8-hydroxyquinoline)aluminum (Alq3)/4,7-diphenyl-1,10-phenanthroline (BPhen) multiple heterostructures acting as an electron transport layer (ETL) were investigated. The operating voltage of the OLEDs with a multiple heterostructure ETL(More)
We report the degradation mechanisms of the silver nanowire (Ag NW) electrodes that play a significantly important role in the stability of wearable and flexible devices. The degradation mechanisms behind the increase in the sheet resistances of Ag NW electrodes were clarified by investigating the variations in the structure and the chemical composition of(More)
The electrical and the optical properties of phosphorescent organic light-emitting devices (PHOLEDs) fabricated utilizing a mixed host emitting layer (EML) consisting of N,N'-dicarbazolyl-3,5-benzene (mCP) and 1,3,5-tri(phenyl-2-benzimidazole)-benzene (TPBi) were investigated to clarify the carrier transport mechanisms of PHOLEDs. While the operating(More)