Electronic states in conjugated polymers probed by excimers

We synthesized an oligomer of O-PPV [poly(2,5-diphenylene-1,3,4-oxadiazolyl e-4,4'-vinylene)] with 4 repeat units. As oxadiazole in the PPV main chain is an acceptor, intermolecular interaction of O-PPV will increase and even produce a charge-transfer complex (excimer) in solid-stare. So we may obtai n the information of electronic structures on conjugated polymers by detect ing the PL characteristics of excimers. The absorption, excitation and phot oluminescence spectra were measured on pristine O-PPV and O-PPV/PEO [poly(e thyleneoxide)]. The results indicate that the strength of the interchain ch arge-transfer is related to the property of excited states. We think that t here are two different processes of photoexcitation transitions in conjugat ed polymers. (C) 2000 Elsevier Science B.V. All rights reserved.