Light emitting devices based on a bifunctional block copolymer containing crown ether spacers

Polymer light emitting diodes (LEDs) and light-emitting electrochemical cells (LECs) were demonstrated with a block copolymer, poly(dibenzo-24-crown-8-co-2,5-dimethoxy-1,4-divinyl benzene) (CE-DMVB), as the luminescent polymer. The LEDs with Al cathode show a turn-on voltage of 7 V, with an electroluminescenc (EL) efficiency of 0.017 cd/A. Light emission was observed in both forward and reverse bias modes for LECs. AFM studies display the improved morphology of emissive layers in LECs, which accounts for the fast response of these devices. Upon addition of poly(ethylene oxide) (PEO), LECs exhibit the turn-on voltage of 2.7 V, with the EL efficiency up to 3.7 cd/A.