Energetic Disorder at the Interface Between Disordered Organic Material and Metal Electrode
S.V. Novikov and G.G. Malliaras
The physics of organic disordered materials is dominated by the effects of energetic disorder. We show that image forces reduce the electrostatic component of the total energetic disorder near an interface with a metal electrode. Typically, the standard deviation of energetic disorder is dramatically reduced at the first few layers of organic semiconductor molecules adjacent to the metal electrode. This means that the use of bulk disorder parameters (such as standard deviation of disorder) for description of the energetic disorder at the interface is poorly justified even in the case of identical spatial and chemical structure of the organic material at the interface and in the bulk of the transport layer. Implications for charge injection into organic semiconductors are discussed.