Conjugated and Nonconjugated Poly p-Phenylene Vinylene Block Copolymers

2 Conjugated and Nonconjugated Poly(p-Phenylene Vinylene) Block Copolymers 

Conjugated segment with trans double bonds 

FIGURE 2.6 The schematic structure of rigid and flexible block PPV containing saturated (unconverted) units and m-vinylene links. (From Son, S., Dodabalapur, A., Lovinger, A. J., and Galvin, M.E., Science, 269, 376, 1995. With permission.) 

Electron acceptor dicyanovinyl and oxadiazole substituents have been recently introduced into phenylene units of the PPV block copolymers (179,180) [211]. Blue and blue-greenish PL emission was observed for 179 and 180, respectively, but the PLQY was relatively low even in solution (13 and 24%) and no EL device has yet been reported. 

Lahti and coworkers [212] reported a series of meta-linked oligo(phenylene vinylene) block copolymers 181a-c. A mem-linked phenylene unit imposed an additional hypsochromic shift on the emission of these segmented polymers. The PL maxima were found at 399-416 nm, but a significant (ca. 70 nm) red shift was observed for EL spectra (ITO/polymer/Ca/Al) (Chart 2.39). 

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