Crown ether substituted phenylenevinylene oligomers: Synthesis and electroluminescent properties

Abstract

Novel phenylenevinylene oligomers substituted with crown ether rings (CE-OPV) were synthesized using a Wittig or Horner–Wadsworth–Emmons reaction. The resulting oligomers give strong fluorescence emission at 515 nm with a quantum efficiency of ca. 80% in MeCN. While light-emitting diodes (LEDs) with the structure ITO/CE-OPV/Al show similar emission to the photoluminescence at a relatively high turn-on voltage of ca. 9 V/100 nm, the corresponding light-emitting electrochemical cells (LECs) with the structure ITO/CE-OPV+LiCF₃SO₃/Al emit bluish-green light at a rather low turn-on voltage of ca. 3 V for both the forward and reverse bias. These results indicate that the chemically-grafted crown ether rings assist ionic conductivity, and thus the CE-OPV is of promise for LEC applications.