Emeraldine Base Polyaniline as an Alternative to Poly(3,4-ethylenedioxythiophene) as a Hole-Transporting Layer

Abstract

The device physics of bilayer polymer light emitting diodes containing either poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] or ladder-type methyl-poly(p-phenylene) active layers have been determined. The active layer was consistent in thickness and general preparation whilst hole transporting layers spin cast from emeraldine base polyaniline protonated with camphorsulfonic acid, emeraldine base polyaniline protonated with 2-acrylamido-2-methyl-1-propanesulfonic acid, and emeraldine base polyaniline protonated with polystyrene sulfonated acid, in various ratios of polyaniline to counter ion, were used in order to determine how various spin-processible polyaniline layers performed relative to a commercially available polystyrene sulfonated acid doped poly(3,4-ethylenedioxythiophene layer. For poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] light-emitting diodes we observe an improvement in performance when using emeraldine base polyaniline protonated with polystyrene sulfonated acid relative to poly(3,4-ethylenedioxythiophene protonated with polystyrene sulfonated acid, with a maximum device external quantum efficiency of 0.6362 % at a current density of 20.18 mA/cm2.