Highly polarized blue electroluminescence from homogeneously aligned filmsof poly(9,9-dioctylfluorene)

Homogeneous alignment of poly(9,9-dioctylfluorene) films on thin layers of rubbed precursor-route poly(p-phenylenevinylene) allows the construction of light-emitting diodes that emit highly polarized blue light (lambda(em)=45 8 nm). The rubbed poly(p-phenylenevinylene) acts as an effective hole-injec ting alignment layer. Annealing of poly(9,9-dioctylfluorene) in its nematic phase followed by rapid quenching orients the polymer as a glassy monodoma in on the alignment layer and gives devices with a polarization ratio of 25 :1 and a luminance of up to 250 cd/m(2). (C) 2000 American Institute of Phy sics. [S0003-6951(00)04620-9].