Electron transport via phenyl–perfluorophenyl interaction in crystals of fluorine-substituted dibenzalacetones

Abstract

Although substitution with fluorine creates stability in organic electronic materials by altering the molecular crystal packing, the charge transport properties of the materials are significantly affected. Phenyl–perfluorophenyl (π–π_F) interaction is a unique intermolecular interaction formed between electropositive perfluorophenyl and electronegative non-fluorinated phenyl, and may have a different charge transport as compared to the π–π interaction formed between ordinary phenyl rings. Three crystals with both π–π_F interaction and intermolecular hydrogen bonding interaction were chosen to study the relationship between intermolecular interactions and their charge transport properties in both the band-like model and the hopping model. In contrast to ordinary π–π interaction, which has been reported to be mainly responsible for hole transport, the π–π_F interaction is mainly responsible for electron transport. Thus, intermolecular π–π_F interaction is an effective packing style to realize the n-type charge carrier. In summary, C–H⋯F interactions are mainly responsible for electron transport while the C–H⋯O interaction is responsible for hole transport.