Coherent Charge Transport Enhanced by Programmed Electrochemical Doping in Conjugated Polymers

Doping is a cornerstone of semiconductor engineering, yet conventional methods lack precise and uniform control over electronic properties. Here, we present a highly controllable voltage-programmed electrochemical doping strategy utilizing pulsed gate voltage sequences to orchestrate anion/cation ingress into polymer matrices. This approach, applied to the benchmark semicrystalline p-type polymer poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene) and the cyano-functionalized bithiophene imide dimer (CNI₂)-based n-type polymer, overcomes the limitations of chemical doping by delivering exceptional scalability and tunability, achieving conductivities of up to 685 and 21 S cm^{- 1}, respectively. These gains arise from optimized electronic properties and enhanced polymer crystallinity enabled by precise voltage-driven ion intercalation. Notably, this enables a Hall mobility of 2.6 cm² V^{- 1} s^{- 1} at 300 K and signatures of mesoscopic phase-coherent transport, as evidenced by the observation of Hall effect signals and positive magnetoresistance associated with weak localization. This study establishes a generalizable framework for engineering charge transport in conjugated polymers for advanced electronic and spintronic applications.