Revisiting the Non-linear transport behaviors in conducting polymer

The non-linear transport in conducting polymers usually refers to the non-ohmic current-voltage (IV) relationship at low temperature, and are widely reported in both molecular doped and field effect doped polymers, power-law dependence of conductance on temperature, at low voltage (eV<<k_BT) and current on voltage, at high voltage (eV>>k_BT) are universally observed in the non-linear regime.
We investigated the charge transport in polymer materials PBTTT doped with 2,3,5,6-Tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), very revealing information was obtained via a simple contrast investigation between PBTTT films of different crystalline degrees. We found that only the transport behavior of highly crystalline PBTTT film at low-T could satisfy what Luttinger Liquid theory predicts, while those of poor ordered film showed non-power-law relationship. Simultaneously, fit of other non-linear transport models with our data was investigated. We final proposed our model based on the microstructure of the PBTTT film with considering the interplay between Fermi liquids and Luttinger liquids.