Unraveling the Solution-State Supramolecular Structures of Donor–Acceptor Polymers and their Influence on Solid-State Morphology and Charge-Transport Properties

Abstract

Polymer self-assembly in solution prior to film fabrication makes solution-state structures critical for their solid-state packing and optoelectronic properties. However, unraveling the solution-state supramolecular structures is challenging, not to mention establishing a clear relationship between the solution-state structure and the charge-transport properties in field-effect transistors. Here, for the first time, it is revealed that the thin-film morphology of a conjugated polymer inherits the features of its solution-state supramolecular structures. A "solution-state supramolecular structure control" strategy is proposed to increase the electron mobility of a benzodifurandione-based oligo(p-phenylene vinylene) (BDOPV)-based polymer. It is shown that the solution-state structures of the BDOPV-based conjugated polymer can be tuned such that it forms a 1D rod-like structure in good solvent and a 2D lamellar structure in poor solvent. By tuning the solution-state structure, films with high crystallinity and good interdomain connectivity are obtained. The electron mobility significantly increases from the original value of 1.8 to 3.2 cm² V⁻¹ s⁻¹. This work demonstrates that "solution-state supramolecular structure" control is critical for understanding and optimization of the thin-film morphology and charge-transport properties of conjugated polymers.

A supramolecular self-assembly strategy is used to control the solution-state structure of a conjugated polymer. It is revealed that the thin-film morphology of the conjugated polymer inherits the features of their solution-state supramolecular structures. Through "solution-state supramolecular structure control", the electron mobility of the polymer is boosted to 3.2 cm² V⁻¹ s⁻¹, nearly doubling the original performance.

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