Design of one-dimensional organic semiconductors with high intrinsic electron mobilities: lessons from computation

Abstract

Aromatic diimides are important building blocks for constructing low-dimensional n-type organic semiconductors. In addition to the mostly-reported perylene and naphthalene diimides, we show that pyrene diimide (PyDI) is a more competitive core to assemble 1D n-type materials with desired charge-transfer properties. The surface mappings of binding energy and transfer integral reveal that intermolecular rotation can lower the repulsive interactions between neighboring molecules and make the local energy minimum conformation coincide with the local maximum of electronic coupling. Peripheral core decoration with cyclohexyl or phenyl groups enables the 1D confinement of π-conjugated cores with suitable twist angles and in-plane displacements, which paves the electron-transport highway within the helical supramolecular aggregates. Molecular dynamics simulations show that these ring-substituted PyDI coupled with soluble aliphatic side chains can self-assemble into well-ordered helices and maintain stable 1D architectures with record-high electron mobilities up to 2.93 cm² V⁻¹ s⁻¹ in CHCl₃ at room temperature. These results and conclusions are a pivotal and necessary step that should stimulate both the proof-of-principle experiments and the computational screenings of high-performance organic materials for micro- or nanodevice applications.