Polyaniline Bilayer Composite Electrode for Efficient Polymer Light Emitting Diodes

We reported that by using a combination of polyaniline (PANI) and Indium/tin oxide (ITO) as the transparent anode of a polymer light emitting diode with poly(2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene), (MEH-PPV), as the active layer, device performance can be significantly improved. The operating voltage can be reduced by ∼ 30-50%, and the quantum efficiency can be increased by ∼ 30-40% with respect to the devices using IT0 alone as the hole-injecting anode. The barrier height at the PANI/MEH-PPV interface is estimated to be ∼ 0.08-0.12eV, approximately half of that at the ITO/MEH-PPV interface.