Aromatic polyethers containing distyrylbenzene and 1,3,4-oxadiazole chromophores: synthesis and electrochemical properties

New aromatic polyethers (P1, P2) containing both electron transporting 1,3,4-oxadiazole and emitting distyrylbenzene chromophores, were prepared from 2,5-bis(4-fluorophenyl)-1,3,4-oxadiazole and aromatic dialdehydes by Homer-Wadsworth-Emmons reaction. Saturated aliphatic segment was also introduced to main chain to improve the! solubility of the polyethers (P3, P4). The reduced viscosities are between 0.23 and 0.42 dl/g. They are amorphous! and thermally stable up to 300 degreesC. In film state, their absorption maxima are in the range of 300-362 nm, while the photoluminescence maxima are within 467-488 nm (blue-green). From cyclic voltammetric and optical investigations, the HOMO and LUMO levels of P1-P4 are estimated to be 5.38-5.47 and 2.55-2.64 eV, respectively. The HOMO levels are greater than PPV (5.1 eV), while the LUMO levels are similar to PPV (2.6 eV). Charge injection balance can be improved (compared with PPV) since the difference between barrier heights of anode and cathode is narrowed down. (C) 2001 Elsevier Science B.V. All rights reserved.