The influence of nanostructure on polymer-based optoelectronic device functioning: A computer simulation study

During the last years it has been clear that it is important to understand and control the nanostructure of the active polymer layer used in optoelectronic devices, like polymer diodes, solar cells or field effect transistors. Several experimental studies have shown that the nanostructure of polymer thin films used in these optoelectronic devices depends on the conditions used to deposit the polymer layer between the electrodes. As a result, in solid state conjugated polymer chains tend to be stacked and aligned relative to the electrodes creating domains with different sizes that influence the performance of these devices. To understand how the spatial arrangement of polymer chains affects the functioning of optoelectronic devices, we performed computer simulations using our mesoscopic model based on a generalized dynamic Monte Carlo method. We focus our study on the influence of the nanomorphology on the electric properties of polymer light emitting diodes. Our results show that for a pristine polymer layer and in the presence of ohmic contacts between the electrodes and the polymer layer, the electric properties of the device, namely current density, charge density, internal electric field and the number of charges that undergo recombination strongly depend on the polymer morphology at nanoscale.