Charge transport in polymer light-emitting diodes

The transport of electrons and holes in poly(dialkoxy-p-phenylene vinylene) (PPV) has been investigated using temperature dependent current density-voltage characteristics and admittance spectroscopy. From admittance spectroscopy, both the electron and hole mobility of PPV can be obtained from a single polymer light-emitting diode (PLED). These experiments reveal that at room temperature the electron transport is strongly reduced with regard to the hole transport. Due to the smaller activation energy of the electron transport the difference between electron and hole transport in PPV diminshes with decreasing temperature.