Visible electroluminescence of polyacetylene derivatives

Electroluminescence (EL) from a series of polyacetylene derivatives such as poly[(o-iso-propylphenyl)acetylene] (PPA-iPr), poly [1-(p-n-butylphenyl)-2-phenylacetylene] (PDPA-nBu) and poly(1-hexyl-2-phenylacetylene) (PHPA) is studied. Red EL from PPA-iPr with a low efficiency, green or blue from PDPA-nBu or PHPA with a relatively high efficiency, which are sandwiched between an indium-tin oxide (ITO)-coated glass substrate and a Mg/Al cathode, have been observed. The EL efficiency of PDPA-nBu can be increased by doping electron transport molecules 2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole (PBD), but has no effect on PHPA.