Stilbenoid phosphors with increased electron affinity: sulfones as electron accepting groups

Stilbenoid compounds are one of the preferred classes of luminescent materi als for the use in light emitting diodes (LEDs). A problem connected with t he use of poly(phenylenevinylene) (PPV) in LEDs is the unbalanced charge ca rrier transport, electron injection from aluminium and electron transport p roperties ere only poor. The substitution with electron accepting groups li ke nitriles is a suitable way to lower the LUMO level of the chromophore, T he electron withdrawing strength of sulfones is comparable to cyanides and the second binding site is useful to attach solubilising side chains. A two -step synthesis of model compounds and polymers from ethene and sulfonyl di bromobenzene and bromo aromatics is described. The electronic spectra of th e model compounds and the polymers are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.