Spontaneous orientation polarization in organic light-emitting diodes

Abstract

Spontaneous orientation polarization (SOP) is inherent in the evaporated films of many organic semiconducting molecules with a permanent dipole moment. A significant electric field is formed in the film due to SOP. Consequently, the properties of organic light-emitting diodes (OLEDs) incorporating such films are influenced. The polarization charge appearing at heterointerfaces dominates the charge injection and accumulation properties. Moreover, SOP correlates with device degradation. In this article, we review the SOP of organic semiconductor films and its influences on the device properties of OLEDs.