A solution-processed n-type conducting polymer with ultrahigh conductivity

Conducting polymers (CPs) with high conductivity and solution processability have made great advances since the pioneering work on doped polyacetylene(1-3), thus creating the new field of 'organic synthetic metals,(4). Various high-performance CPs have been realized, which enable the applications of several organic electronic devices(5,6). Nevertheless, most CPs exhibit hole-dominant (p-type) transport behaviour(7,8), whereas the development of n-type analogues lags far behind and only a few exhibit metallic state, typically limited by low doping efficiency and ambient instability. Here we present a facilely synthesized highly conductive n-type polymer poly(benzodifurandione) (PBFDO). The reaction combines oxidative polymerization and in situ reductive n-doping, greatly increasing the doping efficiency, and a doping level of almost 0.9 charges per repeating unit can be achieved. The resultant polymer exhibits a breakthrough conductivity of more than 2,000 S cm(-1) with excellent stability and an unexpected solution processability without extra side chains or surfactants. Furthermore, detailed investigations on PBFDO show coherent charge-transport properties and existence of metallic state. The benchmark performances in electrochemical transistors and thermoelectric generators are further demonstrated, thus paving the way for application of the n-type CPs in organic electronics.

Automated summary

This research introduces a facilely synthesized highly conductive n-type polymer with breakthrough conductivity and solution processability. By improving doping efficiency, the polymer achieves a doping level of almost 0.9 charges per repeating unit. Further investigations demonstrate the coherent charge-transport properties and existence of metallic state. The benchmark performances in electrochemical transistors and thermoelectric generators are also demonstrated.