Solvent-Guided Chiral Assemblies and Chemical Doping of OEG-Functionalized Conjugated Polymers.

Abstract

Chiral assembly of achiral conjugated polymers has emerged as a new avenue to promote (opto)electronic properties and control the angular momentum of charge carriers and photons. Solvent plays a key role in chiral emergence through the lyotropic liquid crystal (LLC) assembly pathway, yet rules underpinning solvent effect remain elusive. Here, we establish a unifying framework linking solvent quality to aggregate structure and supramolecular chirality. Using redox active conjugated polymers as model systems, we reveal two types of solution aggregation: (1) β1 aggregation, defined by fibrillar structures with weak interchain coupling and torsional backbone, promotes LLC-mediated chiral assemblies via formation of helical fibers; (2) β2 aggregation, characterized by stacked fibrils with strong interchain coupling and reduced backbone torsion, suppresses chirality. Temperature-dependent studies show that β2 aggregates revert to β1 upon heating, thus restoring chiral assemblies. Extending to 6 conjugated polymers across 37 polymer-solvent-temperature combinations, we demonstrate the universal link between aggregate type and chiral emergence. Further, chemical doping of chiral films derived from β1 aggregates elevates electrical conductivity by up to 100-fold across nine polymer-solvent pairs spanning a wide range of processing conditions. These findings reveal general principles for solvent-guided chiral assembly enabling high-performance chiral electronics, optoelectronics and spintronics.