| abstract |
A polymer comprising a region having a conjugated backbone capable of transporting negative charge carriers, which region comprises a plurality of repeat units each comprising a core group which comprises an [ Ar'] group substituted with at least one pendant group X and the [ Ar'] groups form at least a part of the backbone, wherein each Ar' comprises an aromatic or heteroaromatic group and each X comprises NAr2 in which each Ar is the same or different and independently comprises a substituted or unsubstituted aromatic or heteroaromatic group and N is conjugated with the backbone. |