Charge injection from polyaniline-poly (methylmethacrylate) blends into poly (p-phenylene vinylene)

Blends of polyaniline doped with camphorsulfonic acid, (PAni-CSA), and poly (methylmethacrylate) (PMMA) are important candidates for hole injection electrode material in organic light emitting devices. We present a quantitative analysis of the potential barrier heights at interfaces between the PAni-CSA/PMMA blend and poly-(p-phenylene vinylene) (PPV). The barrier height determination, which is of crucial importance for radiant efficiency control of organic light emitting diodes, is based on temperature dependent tunneling current measurements. The value of the [PAni-CSA/PMMA]/PPV potential barrier height is found to be independent of the PAni-CSA concentration in the blend, except near the percolation threshold, where an increase in the barrier height value is observed. (C) 1998 American Institute of Physics.