title: Control of charge transport in a semiconducting copolymer by solvent-induced long-range order.
abstract: Recent reports on high-mobility organic field-effect transistors (FETs) based on donor-acceptor semiconducting co-polymers have indicated an apparently strong deviation from the paradigm, valid for a series of semi-crystalline polymers, which has been strictly correlating charges mobility to crystalline order. This poses a severe limit on the control of mobility and a fundamental question on the critical length scale which is dominating charge transport. Here we focus on a well-known model material for electron transport, a naphthalene-diimide based copolymer, and we demonstrate that mobility can be controlled over two orders of magnitude, with maximum saturation mobility exceeding 1 cm(2)/Vs at high gate voltages, by controlling the extent of orientational domains through a deposition process as simple as spin-coating. High mobility values can be achieved by adopting solvents inducing a higher amount of pre-aggregates in the solution, which through the interaction with the substrate, provide the polymer with liquid-crystalline like ordering properties.
authors.affiliation: Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via G. Pascoli 70/3, 20133 Milano, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Luzio
authors.forename: Luigino
authors.initials: L
authors.lastname: Criante
authors.forename: Valerio
authors.initials: V
authors.lastname: D'Innocenzo
authors.forename: Mario
authors.initials: M
authors.lastname: Caironi