Electron transport in pristine and alkali metal doped perylene-3,4,9,10-tetracarboxylicdianhydride (PTCDA) thin films

The controlled adjustment of the conductivity of molecular organic semiconductors is essential for their technical application. As the n-type organic semiconductor perylene-3,4,9,10-tetracarboxylicdianhydride (PTCDA) is known to be n doped by alkali metals, pristine and sodium doped PTCDA was chosen as a model system to investigate the charge carrier generation and transport in organic semiconductors. Temperature-dependent conductivity measurements were performed to obtain information about the transport mechanism. Measurement of the thermoelectric force, i.e., the Seebeck coefficient, gives a closer insight into the energy levels, participating in charge carrier generation. Based on the performed measurements a model for charge carrier transport in pristine and in alkali metal doped PTCDA is suggested.