Blue-green light-emission LECs based on block copolymers containing di(α-naphthalene vinylene)benzene chromophores and tri(ethylene oxide) spacers

The polymer light-emitting electrochemical cells (LECs) were fabricated and characterized with two novel block copolymers as the luminescent polymers. The block copolymers are composed of the rigid segments (chromophores), 1,4-di(α-2-naphthalene vinylene)benzene (DNVB) or 2,5-dimethyloxy-1,4-di(α-2-naphthalene vinylene)benzene (MDNVB) and the flexible segments (spacers), tri(ethylene oxide) (TEO). Efficient blue-green light emission of the LECs was demonstrated with onset voltage lower than 3 V and electroluminescence (EL) efficiency of ∼0.2 cd/A. The a.c. impedance data indicate that the operation mechanism of the LECs agrees with the electrochemical doping model.