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  • Closing the loop between microstructure and charge transport in conjugated polymers by combining microscopy and simulation
Title: Closing the loop between microstructure and charge transport in conjugated polymers by combining microscopy and simulation
A grand challenge in materials science is to identify the impact of molecular composition and structure across a range of length scales on macroscopic properties. We demonstrate a unified experimental–theoretical framework that coordinates experimental measurements of mesoscale structure with molecular-level physical modeling to bridge multiple scales of physical behavior. Here we apply this framework to understand charge transport in a semiconducting polymer. Spatially-resolved nanodiffraction in a transmission electron microscope is combined with a self-consistent framework of the polymer chain statistics to yield a detailed picture of the polymer microstructure ranging from the molecular to device relevant scale. Using these data as inputs for charge transport calculations, the combined multiscale approach highlights the underrepresented role of defects in existing transport models. Short-range transport is shown to be more chaotic than is often pictured, with the drift velocity accounting for a small portion of overall charge motion. Local transport is sensitive to the alignment and geometry of polymer chains. At longer length scales, large domains and gradual grain boundaries funnel charges preferentially to certain regions, creating inhomogeneous charge distributions. While alignment generally improves mobility, these funneling effects negatively impact mobility. The microstructure is modified in silico to explore possible design rules, showing chain stiffness and alignment to be beneficial while local homogeneity has no positive effect. This combined approach creates a flexible and extensible pipeline for analyzing multiscale functional properties and a general strategy for extending the accesible length scales of experimental and theoretical probes by harnessing their combined strengths.  more » « less
Award ID(s):
1855334
PAR ID:
10475284
Author(s) / Creator(s):
; ; ; ; ;
Publisher / Repository:
Proceedings of the National Academy of Sciences of the United States of America
Date Published:
Journal Name:
Proceedings of the National Academy of Sciences
Volume:
119
Issue:
46
ISSN:
0027-8424
Page Range / eLocation ID:
e2204346119
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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