Self-assembly, optical and electrical properties of five membered O- or S-heterocyclic annulated perylene diimides

In this work, a new asymmetrically five-membered O-heterocyclic annulated perylene diimide (O-PDI) has been synthesized. The compounds O-PDI and asymmetrically five-membered S-heterocyclic annulated perylene diimide (S-PDI) self-assembled into nanoneedle and nanosheet, respectively. Photo physical, electrochemical and thermal properties were investigated by UV-vis absorption, fluorescence, cyclic voltammetric, thermogravimetric and differential scanning calorimetry techniques. Optical, fluorescence, scanning and transmission electron microscopies were employed in the molecular self assembly studies. Due to significant electronic coupling between their heteroatom/heterocycles and perylene diimide (PDI) cores, the intermolecular pi-pi actions are neglectable, providing high luminescence efficiency. At the same time, the space between perylene chromophores is still very short (3.3 angstrom for O-PDI and 3.23 angstrom for S-PDI), which is favorable for the hopping transportation of charge carrier from one molecule to a neighboring one. These compounds could be candidate materials for acquiring well defined organic nanostructures with both excellent charge-transporting and good light-emitting capabilities. (C) 2016 Elsevier Ltd. All rights reserved.