ELECTROLUMINESCENCE IN CONDUCTING POLYMERS BASED ON POLY(PHENYLENE ETHYNYLENE)

Electroluminescence (EL) in various conducting polymers (CP) based on poly(phenylene ethynylene) (ROPPE) which have C-C triple bond in their main chains were studied. EL in Al/CP/ITO structure utilizing copolym er based on ROPPE and pyridine as CP was blue-green and stronger than that in same structure utilizing well-known poly(dialkoxy-p-phenylene vinylene) (ROPPV). However, weaker red EL was observed in same structu re utilizing copolymer based on ROPPE and anthracene. These result sug gests that the increased band gap energy and improve exciton confineme nt efficiency, due to shortened conjugate length, were realized by int roduction of C-C triple bonds in main chain of conducting polymers suc h as ROPPV, while these effects of C-C triple bonds are suppressed by introduction of electron-rich moiety such as anthracene which should i ncrease effective conjugation length. Electrochemical studies on these copolymers also confirmed this interpretation.