Polymorph Influence on Sequential Anion Exchange Doping and Charge Transport in Poly(didodecyl-quaterthiophene) (PQT) for Organic Thermoelectrics
Year: 2026
Type: preprint
Abstract: Anion exchange doping (AED) is a key strategy for optimizing organic thermoelectrics (OTEs).However, the influence of specific polymer microstructures like polymorphs on AED has received relatively little attention.Here, we investigate the interplay between thermally induced polymorphism in poly(dodecyl-quaterthiophene) (PQT) and sequential AED efficiency using FeCl3 and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).By precisely fabricating microstructural gradients via a custom thermal annealing stage, we rapidly screen AED behavior across a spectrum of structural states within a single PQT film.We reveal that pre-set polymorphism acts as a fundamental gating mechanism for dopant infiltration.The expanded lamellar spacing of the (100) polymorph, formed after annealing at elevated temperatures, allows for greater dopant uptake, and thus enables electronic conductivity () as high as 522.0 ± 23.0 S/cm and a maximum power factor of 15.4 μW/mK 2 .Conversely, the tighter (100)' polymorph restricts doping level and structural ordering.This work establishes that pre-forming the (100) polymorph is a critical prerequisite for maximizing charge transport and thermoelectric performance in sequentially doped PQT.
Source: ChemRxiv
Institution: University of Chicago
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7220445251