New conjugated materials containing cyano substituents for light-emitting diodes

New electroluminescent cyano-substituted phenylenevinylene (PV) monomeric and oligomeric chromophores, 1–3, were synthesized by Knoevenagel condensation and investigated in terms of their photoluminescence (PL) and electroluminescence (EL) behavior. All show PL emission maxima between 463 and 471 nm in solution with quantum efficiencies of 0.65, 0.46 and 0.68, respectively. EL maxima in an LED configuration ITO/PEDOT–PSS/1–3/Ca–Al were 507, 518 and 551 nm with luminance efficiencies 0.01, 0.05 and 0.02 cd/A, respectively.