Separated crystallization of donor and acceptor in oligo(p-phenylenevinylene)-naphthalenediimide dyad films

A dyad molecule was synthesized, with oligo(p-phenylenevinylene) (OPV) as the electron donor and naphthalene diimide (NDI) as the acceptor. The optical, thermal, and X-ray diffraction measurements of the film structure showed that the OPV and NDI moieties of the dyad crystallized separately in the spin-coated films. This is in striking contrast to the previously reported OPV and C70 fullerene dyad, in which the introduction of C70 severely disrupted the OPV packing. The separated crystallization in the OPV–NDI dyad was attributed to the planar shape of the acceptor and the differences in the crystalline structures of planar NDI and rod-like OPV.