Two-Dimensional Electron Transport in N-Type Conducting Polymers by Dication Exchange

The limitation of intrachain charge delocalization and the low efficiency of interchain hopping transport are known to greatly impede the electrical conductivity of organic conducting polymers. In comparison with intrachain electron transport, the achievement of efficient interchain transport remains a significant challenge in n-type conducting polymers. Electron delocalization between polymer chains upon introducing conjugated counterions while keeping weak Coulombic interactions is able to form two-dimensional transport ways and greatly increase the electrical conductivity. In this work, we investigated the ion-exchange process in a highly doped n-type conducting polymer, named poly(benzodifurandione) (PBFDO), with cations of varied valence states. Among them, dication exchange of proton (H + ) on PBFDO resulted in significantly enhanced electrical conductivity, which was attributed to the increased electron transport and an improved microstructure, by diminished Coulomb interactions and a strong interchain charge transport. Notably, the tight intermolecular stacking and enhanced electron transport led to the redistribution of electron density of states which together contributed to the metallic conduction behavior after the dication exchange. This work highlights the potential of the dication-exchange strategy as a versatile tool for tailoring the electronic properties of n-type conducting polymers, paving the way for next-generation organic electronic devices.