Abstract
Organic conjugated polymers demonstrate great potential in transistors, solar cells and light-emitting diodes, whose performances are fundamentally governed by charge transport. However, the morphology–property relationships and the underpinning charge transport mechanisms remain unclear. Particularly, whether the nonlinear charge transport in conducting polymers is appropriately formulated within non-Fermi liquids is not clear. In this work, via varying crystalline degrees of samples, we carry out systematic investigations on the charge transport nonlinearity in conducting polymers. Possible charge carriers’ dimensionality is discussed when varying the molecular chain’s crystalline orders. A heterogeneous-resistive-network (HRN) model is 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. The HRN model is supported by precise electrical and microstructural characterizations, together with theoretic evaluations, which well describes the nonlinear transport behaviors and provides new insights into the microstructure-correlated charge transport in organic solids.
Highlights
Organic conjugated polymers demonstrate great potential in transistors, solar cells and lightemitting diodes, whose performances are fundamentally governed by charge transport
Luttinger liquids (LL) theory usually relates to strict onedimensional (1D) systems with strong electron correlation, and its nonlinear current–voltage (I–V) behaviors usually stem from the power-law type density of states (DOS) near the Fermi level
By treating strongly-coupled chains in crystalline grains and weakly-coupled ones in the amorphous region as Fermi liquids (FL) and LLs, respectively, we find that the tied link between FLs and LLs accounts for the nonlinear charge transport behaviors
Summary
Organic conjugated polymers demonstrate great potential in transistors, solar cells and lightemitting diodes, whose performances are fundamentally governed by charge transport. One of the most discussed electrical behaviors regarding polymers is whether their nonlinear transport behavior, i.e., the current I exhibits power-law dependence on both temperature T (I ∝ Tα) and voltage V (I ∝ Vβ)[6,7,8,9,10,11,12,13,14], is possibly related to Luttinger liquid (LL) features This discussion was, to a great extent, provoked by the apparent agreements between LL theory and the experimental results for field-effect doped conducting polymers[15]. To unveil the origin of power-law nonlinear transport behavior in conducting polymers, the film microstructures, at least those that influence the dimensionality of carriers, should be taken into consideration
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