Fabrication and characterization of two-layered polymer light emitting diode with a structure of ITO/PEDOT:PSS/ MEH:PPV/Al

In this article, we present fabrication and characterization of two-layered polymer light emitting diode (PLED) with a structure of ITO/PEDOT:PSS/MEH:PPV/Al which emits a orange-colored light, with the aim of reduction of lightening voltage. In this work, the PEDOT:PSS layer, as hole injection layer, was coated with spin coating method and a rotating speed of 2000 rpm and the MEH:PPV layer, as an active layer (emission layer), was coated with four rotating speeds. The impact of change in layer thickness on the surface roughness, optical absorption, and most importantly, the lightening voltage was investigated. Eventually, a PLED with a structure of ITO/PEDO:PSS(2000 rpm)/MEH:PPV(6000 rpm)/Al (165 nm) was selected as the optimum structure with a minimum lightening voltage of 7.1 V. The emission light ranged from 550 nm to 650 nm and was observed as an orange light.