Influences of evaporation temperature on electronic structures and electrical properties of molybdenum oxide in organic light emitting devices

The influence of evaporation temperatures on the electronic structures of molybdenum oxide (MoOx) films and the electrical properties of organic light emitting diodes were investigated. MoOx films evaporated at a high temperature and a high deposition rate are close to a stoichiometric phase, but become less effective when they are used as a hole injection layer. However, when MoOx is evaporated at a lower temperature and a slower rate, there are large amounts of defect-related states present in the forbidden gap, which make the films behave like a high work function conductor and an effective hole injection layer. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3309783]