Single carrier devices with electrical doped layers for the characterization of charge-carrier transport in organic thin-films

We introduce single-carrier devices with electrical doped layers as a concept for the characterization of charge-carrier transport in organic semiconductors. In this approach, individual organic layers from a multilayer device are investigated in single-carrier test devices, where they are enclosed by symmetrically arranged electrical doped layers of equal thickness and composition. Single carrier devices without electrical doped layers are usually difficult to interpret due to an uncertainty about interface dipole effects between the metal contacts and pristine organic layers. In comparison, our devices show Ohmic contacts at the electrodes as well as zero built-in voltage and thus allow a more direct insight into charge-carrier transport. State-of-the-art simulation models are applied to analyze current-voltage characteristics and evaluate crucial parameters such as energy barriers between adjacent organic layers and mobilities. (c) 2010 American Institute of Physics. [doi: 10.1063/1.3460528]