COMPARISON OF ELECTROLUMINESCENT QUANTUM EFFICIENCIES OF PPV AND A PPV-RELATED ALTERNATING BLOCK-COPOLYMER

A comparison of the electroluminescent properties of poly(p-phenylene vinylene) (PPV) and a conjugated/non-conjugated alternating block copo lymer has been made. The chromophoric sequences in the latter contain about 76 mol% of sequences containing three phenylene or dimethoxy phe nylene rings interspersed with vinylene units, with the remaining chro mophores being a distribution of longer sequences containing additiona l phenylene vinylene units. Photoluminescent and electroluminescent sp ectra of PPV and the block copolymer are very similar, but the quantum efficiency of the latter is up to two orders of magnitude greater. Th is is attributed largely to morphological differences between the two macromolecules; the block copolymer can provide greater excitonic conf inement by virtue of a phase-segregated morphology. (C) 1998 Elsevier Science S.A.