Cross-linkable polymers based on dialkylfluorenes

We have prepared a series of cross-linkable oligo- and poly(dialkylfluorene )s by nickel(0)mediated polymerization of 2,7-dibromo-9,9-dialkylfluorene ( alkyl = n-hexyl) and 4-bromo-styrene. The resulting fully soluble and proce ssable, styryl-functionalized oligomers and polymers can be cross-linked vi a the vinyl end-groups by curing at 175-200 degrees C, consistent with the autopolymerization mechanism of styrene, These relatively mild conditions r ender the materials insoluble and enable multilayering of polymers in organ ic light emitting devices. At the same Lime, the electrical and/or optical properties of the cross-linked polymers are preserved and no deleterious sp ecies or undesirable byproducts are produced. Furthermore, the cross-linkin g allows control of the supramolecular ordering of the planarized rigid rod -type fluorene segments in the polymer backbone that leads to suppression o f troublesome excimer/aggregate in the photo- and electrolumenescence.