Band alignment at metal/organic and metal/oxide/organic interfaces

Charge injection at metal/organic interfaces dictates the performance, lifetime, and stability of organic electronic devices. We demonstrate that interface dipole theory, originally developed to describe Schottky contacts at metal/semiconductor interfaces, can also accurately describe the injection barriers in real organic electronic devices. It is found that theoretically predicted hole injection barriers for various archetype metal/organic and metal/oxide/organic structures are in excellent agreement with values extracted from experimental transport measurements. Injection barriers at metal/organic and metal/oxide/organic interfaces can therefore be accurately predicted based on the knowledge of only a few fundamental material properties of the oxide and organic layers.