Effect of Au Nano-Particles in PEDOT:PSS Hole Injection Layer on the Properties of Green Polymer Light-Emitting Diodes

Polymer light-emitting diodes (PLEDs) were prepared by spin coating and thermal evaporation methods with the structure of glass/ITO/PEDOT:PSS+Au nano-particles (NPs)/PVK:Ir(ppy)(3)/TPBI/LiF/Al. The PEDOT:PSS was used for the hole injection layer. In order to improve the light efficiency of the devices, the PEDOT:PSS material was doped with Au NPs. The effects of Au NP concentrations on the electrical and optical properties of PLEDs were investigated. The doping concentrations of Au NPs were changed within the range from 0.1 to 1.0 vol. %. The optimum doping concentration of Au NPs was observed at 0.5 vol. %, indicating that the maximum luminance and current density were about 2.4 x 10(4) cd/m(2) and 0.16 A/m(2) at 11 V, respectively. The PLEDs showed a green emission color. Au NPs doped in PEDOT:PSS played a role in enhancing the light efficiency of the PLEDs, which may be attributed to the localized surface plasmon resonance phenomenon.