The effect of the intramolecular properties in single-carrier polymer diodes

Abstract

The electric behaviour of polymer diodes has the influence of several factors such as the electrodes work function, the experimental conditions used to deposit the active component or the chemistry of the polymer. Although experimentally it is possible to study the effect of some of these factors on the device performance, for instance by changing the chemical structure of the polymer used or the type of electrodes, it is impossible to study individually each one of these effects because changing one of them can influence the others. Quantum mechanical calculations have shown that depending on the chemical structure of the polymer, its intramolecular properties (e.g. ionization potential, electron affinity or intramolecular charge mobility) can be changed. To understand the effect of the intramolecular properties in the performance of polymer diodes we use a generalized dynamical Monte Carlo method that considers the nanostructure of the polymer layer and the main electronic processes involved in diode functioning. Our results show that the influence of the intramolecular properties on the electric behaviour of pristine polymer-diodes with ohmic contacts depends on the morphology of the polymer layer at nanoscale that can alter not only hole and electron current density for the same applied electric field but also charge density and charge distribution inside the polymer layer.