The relationship between intermolecular interactions and charge transport properties of trifluoromethylated polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) with the electron-withdrawing groups such as halogen atom, cyanide, perfluoroalkyl (PFA), or perfluoroary, etc. exhibit good air stability and better solid-state charge carrier mobility. To obtain a better understanding of structure property relationships of this kind of compounds, a series PAH(CF3)(n) derivatives a1, a2, b1, b2, c1, and c2, which contain different numbers of trifluoromethyls and benzene rings, were chosen and studied by both band-like model and hopping model. Their crystals contain different intermolecular interactions. It turns out that intermolecular hydrogen bonding interactions are mainly responsible for electron transport, while pi-stacking interactions dominate hole transport. When the pi-stacking and intermolecular hydrogen bonding interactions coexist in the same direction, a competitive relationship occurs between hole and electron transport, which tend to cause enhancement of electron transport, and restrain hole transport. (C) 2014 Elsevier B. V. All rights reserved.