Abstract
Organic conjugated polymers demonstrate great potential in the transistor, solar cell and light-emitting diodes. The performances of those devices are fundamentally governed by charge transport within the active materials. However, the morphology-property relationships and the underpinning charge transport mechanism in polymers remain unclear. Particularly, whether the nonlinear charge transport in doped conducting polymers, i.e., anomalous non-Ohmic behaviors at low temperature, is appropriately formulated within non-Fermi liquid picture is not clear. In this work, via varying crystalline degrees of samples, we carried out systematic investigations on the charge transport nonlinearity in conducting polymers. Possible charge carriers’ dimensionality was discussed with experiments when varying the molecular chain’s crystalline orders. A heterogeneous-resistive-network (HRN) model was proposed based on the tied link between Fermi liquids (FL) and Luttinger liquids (LL), related to the high-ordered crystalline zones and weak-coupled amorphous regions, respectively. This mesoscopic HRN model is experimentally supported by precise electrical and microstructural characterizations, together with theoretic evaluations. Significantly, such model well describes the nonlinear transport behaviors in conducting polymers universally and provides new insights into the microstructure-correlated charge transport in organic conducting/semiconducting systems.
