| abstract |
A composition comprising a polymer and a phosphorescent material wherein the polymer comprises repeat units of formula (I): n n n n n n n n n n wherein A is a heteroaryl group containing a nitrogen atom, and A may be unusubstituted or substituted with one or more substituents;n R 1 in each occurrence is independently a substituent; and n is 0, 1, 2, 3 or 4. |