Relationship between Mobility and Lattice Strain in Electrochemically Doped Poly(3-hexylthiophene)

Conjugated semiconducting polymers, such as poly(3-hexylthiophene) (P3HT), are poised to play an integral role in the development of organic electronic devices; however, their performance is governed by factors that are intrinsically coupled: dopant concentration, carrier mobility, crystal structure, and mesoscale morphology. We utilize synchrotron X-ray scattering and electrochemical impedance spectroscopy to probe the crystal structure and electronic properties of P3HT in situ during electrochemical doping. We show that doping strains the crystalline domains, coincident with an exponential increase in hole mobility. We believe these observations provide guidance for the development of improved theoretical models for charge transport in semiconducting polymers.