Papers by Keyword: Polymer Light Emitting Diode

Abstract: High efficient white polymer light-emitting diodes (WPLEDs) were fabricated with blue- fluorescent polymers(PFO) and yellow- phosphorescent polymers(PFCz₂-NPYIrm₅) blending as light emitting layer, and a water/alcohol-soluble polymer poly [(9,9-bis(3′-((N,N-dimethyl)-N-ethylammonium)propyl)-2,7-fluorene)-2,7-(9,9-dioctylfluorene) - 4,7-(2,1,3- benzoselenadiazole)]dibromide(PFN) as electron injection layer. The structure of the devices used here is: ITO/PEDOT-PSS(40nm)/PVK(30nm)/PFO: PFCz₂-NPYIrm₅ (60nm)/PFN(20nm)/Ba(4nm)/Al(120nm). When the doping concentration of PFCz₂-NPYIrm5 was 1% and PFN film thickness was about 20nm, the EL emissions from the host and the guests were observed simultaneously and the efficient white light emission with coordinates of (0.34,0.32) was achieved. A maximum external quantum efficiency of 4.8% and luminous efficiency of 6.6cd/A was obtained at 8.5V.

Abstract: Polymer light emitting diodes (PLEDs) with ITO/PEDOT:PSS/PVK/PFO-poss/LiF/Al structure were prepared by spin coating method on the plasma-treated ITO(indium tin oxide)/glass substrates. PVK(N-vinylcabozole) and PEDOT:PSS [poly(3,4-ethylenedioxythiophene):poly(styrene sulfolnate)] polymers were used as hole injection and transport materials. As blue light emitting material, PFO-poss(poly(9,9-dioctylfluorence) polymer was used. The dependence of the plasma treatment of ITO films on the optical and electrical properties of the PLEDs was investigated. The sheet resistance of ITO films increased slightly with increasing the plasma intensity from 20W to 300W in RF power. In contrast, the surface roughness was improved as the plasma intensity increased. The maximum current density and luminance were about 20 mA/cm2 and 250 cd/m2 at 9 V for the PLED sample coated on ITO/glass substrate with plasma treatment of 100W for 30s under 40 mtorr O2 pressure. The maximum emission spectrum of the PLEDs was 441 nm showing blue color.

Abstract: The properties of photoluminescence (PL) and electroluminescence (EL) of 5,10,15,20- tetra-p-tolyl-21H, 23H-porphine (TTP) doped poly[2-methoxy-5-(2’-ethylhexyloxy)-1,4- phenylenevinylene] (MEH-PPV) was studied in this paper. A multi-color emission from the corresponding light-emitting device was observed.

Abstract: Polymer light emitting diodes (PLEDs) with ITO/PEDOT:PSS/MEH-PPV/LiF/Al structures were prepared by spin coating method on the patterned ITO(indium tin oxide)/glass substrates. MEH-PPV [Poly(2-methoxy-5(2-ethylhexoxy)-1,4-phenylenevinyle)] and PEDOT:PSS [poly(3,4-ethylenedioxythiophene):poly(styrene sulfolnate)]
polymers were used as the light emitting and hole transport materials. The dependence of the plasma treatment of ITO anode films on the optical and electrical properties of the PLEDs was investigated. The sheet resistances increased with increasing the plasma intensities from 40W to 300W in RF power. In contrast, the surface roughness was improved as the plasma intensity increased. The maximum current density and luminance were found to be about 97.5 mA/
and 55 cd/m2 at 8 V for the PLED sample coated on ITO/glass substrate with plasma treatment of 100W for 30s under 40 mtorr O2 pressure.