Emitting polymers containing cyano groups. Synthesis and photophysical properties of a fully conjugated polymer obtained by Wittig reaction

A new electroluminescent fully conjugated, substituted PPV-related structur e was synthesized. The ring-substituted units (2,5 hexadecyloxy and 2,5 cya no) were interspersed by one non-substituted PPV unit. The EL emission was centered at 612 nm (orange). Double layer devices using PPV as a hole-trans porting material showed 3000 cd/m(2) at a 20 V bias. In addition to the better transport characteristics imparted by the PPV lay er, Forster transfer at the interface provided a better light output in the se devices in comparison with single layer LEDs. Increases in PPV thickness yielded a slight blue shift suggesting that emission from the bulk PPV was occurring as well. (C) 2000 Elsevier Science Ltd. All rights reserved.