Interface properties of a [Li.sub.3]P[O.sub.4]/Al cathode in organic light emitting diodes

The interfaces of the organic semiconductor with the [Li.sub.3]P[O.sub.4]/Al bilayer cathode are examined by using photoelectron spectroscopy to analyze the origin behind the efficient electron injection. The estimate of the surface potential drop caused by those dipoles has accounted for the work function lowering and has described the highly efficient electron injection property of the [Li.sub.3]P[O.sub.4]/Al cathode in an organic light emitting diode (OLED).