The dynamic formation of trions in conjugated polymers

The dynamic formation process of a trion by recombination of an on-chain bipolaron with an off-chain counterion trapped in a radical molecule, under the influence of an external electric field, has been investigated using a nonadiabatic evolution method. We demonstrate that the dynamic formation of the trion depends sensitively on the strength of the applied electric field, the radical potential, and the coupling between the polymer chain and radical. The trion can be formed efficiently via the bipolaron-trapped counterion reaction under the appropriate conditions. Our simulation provides theoretical evidence for the trion formation channel proposed by Kadashchuk et al. The bipolaron-trapped counterion reaction also makes an additional contribution to electroluminescence in conjugated polymers that lies beyond the set of processes involving polaron recombination.

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► We have investigated the collision processes of a charged bipolaron with a trapped counterion.
► The trion can be formed efficiently via the bipolaron-trapped counterion reaction.
► Our results provide theoretical evidence for the trion-forming model proposed by Kadashchuk et al.
► Trion plays an important role in the electrical and optical process due to its large yield.