Concentration effects on intrachain polaron recombination in conjugated polymers

Abstract

The influence of different charge carrier concentrations on the recombination dynamics between oppositely charged polarons is numerically investigated using a modified version of the Su–Schrieffer–Heeger (SSH) model that includes an external electric field and electron–electron interactions. Our findings show that the external electric field can play the role of avoiding the formation of excited states (polaron–exciton and neutral excitation) leading the system to a dimerized lattice. Interestingly, depending on a suitable balance between the polaron concentration and the electric field strength, the recombination mechanism can form stable polaron–excitons or neutral excitations. These results may provide guidance to improve the electroluminescence efficiency in Polymer Light Emitting Diodes.