Solution-State Programming of Crystallinity in Conjugated Polymer Nanowires for Customized Electronics

Abstract

Recent advances in solution-state electron microscopy have enabled direct visualization of molecular assembly of polymers. However, controlling the crystallinity within the polymer nanostructures which result in electronic and mechanical properties remains challenging. Here, we demonstrate a strategy to control the degree of crystallinity in conjugated polymer nanowires within solution, allowing selective formation of highly ordered (≈70%) and partially ordered (≈20%) assemblies. These nanowires were visualized by transmission electron microscopy (TEM) and analyzed in pixel scale, revealing distinct molecular arrangements that influence π-π stacking coherence and interchain alignment. When incorporated into thin-film transistors, the highly crystalline nanowires exhibited enhanced charge mobility, while the less ordered ones retained high stretchability. Furthermore, their controlled blending enabled simultaneous optimization of electrical performance and mechanical flexibility. This microscopy-guided approach highlights the potential of solution-phase crystallinity programming as a tool for designing multifunctional polymer assemblies with tunable structure-property relationships.