High electrical conductivity induced by charge transfer interactions in naphthalenediimide derivatives

Abstract

Various studies have shown the influence of aliphatic, aromatic and bulky side chains on the optical, electrical conductivity and charge transport properties of naphthalenediimide (NDI) derivatives. The morphology, structural arrangement and the aggregation behaviour of these derivatives play an important role in influencing the charge transfer interactions between the donor and acceptor. These properties influence the electrical conductivity of the derivatives due to presence of charge transfer interactions. The present work focuses on the structure property relationship of the four NDI derivatives (SB-NDI) synthesized by imidization of dianhydride precursor with primary amine terminated Schiff bases (SB). The SB-NDI derivatives bear terminal phenyl ring attached to NDI through unsaturated or double unsaturated linkers bearing different electron withdrawing and donating groups. Among these, SB-NDI-2 derivative bearing –NO2 group in trans position at the terminal phenyl ring shows lowest –ΔGoET(CS) which allows favorable intramolecular charge separation. The Scanning electron microscopy shows ribbon like morphology for SB-NDI-2. The micron sized ribbons provide better charge transport and a conductivity of ∼1 Sm−1 at the room temperature without any additives. The special structure of SB-NDI provides charge transport properties allowing wide applications in the field of optoelectronics.