Improved performance of polymer light-emitting devices based on blend of MEH–PPV and vinyl copolymer with 1,3,4-oxadiazole chromophores

We have developed a simple method to overcome the intrinsic defect of well-known poly[2-methoxy-5-(2′-ethylhexoxy)–p-phenylenevinylene] (MEH–PPV), i.e. rampant inter-chain interaction and imbalanced hole and electron fluxes, by blending with copolymer of polystyrene containing pendant aromatic 1,3,4-oxadiazole (PSOXD12). The addition of PSOXD12 reduces the inter-chain interaction and balances charge carrier transport simultaneously. Photoluminescence (PL), PL excitation and electroluminescence (EL) spectra of the blends reveal that the inter-chain interactions, such as aggregation and excimer/exciplex, are reduced markedly due to the presence of PSOXD12. Enhanced EL device performance has been achieved (16,261 cd/m2, 4.79 cd/A) as a result of both reduced inter-chain interaction and balanced charge transport.