Polyfluorenes as materials for photoluminescence and electroluminescence

In a light-emitting organic solid state device in which an active layer comprising an electrically activated luminescent organic polymer is positioned between a hole-injecting electrode and an electron-injecting electrode, the improvement comprising employing a polyfluorene compound comprising from about 3 to about 10,000 repeat units of the formula ##STR1## wherein R1 is an aliphatic goup including at least one polar heteroatom-containing group selected from the group consisting of cyano-substituted alkyls containing 1 or 2 cyanos on a 4 to 10 carbon atom linear or branched alkyl and polyethers containing 2 to 5 ether oxygens separated from one another by 1, 2 or 3 carbon alkyl bridges and R2 is selected from the group consisting of hydrogen, alkyls and aliphatic groups including at least one polar heteroatom-containing group, as the electrically activated luminescent organic polymer.