Patent ID: 7893172

Claim:
An oligomer or polymer comprising a first repeat unit and a second repeat unit that is different from the first repeat unit, the first repeat unit having formula (I): wherein each E independently represents a nitrogen or a phosphorus atom, with the proviso that at least one E is a phosphorus atom; each Ar 1 , Ar 2 and Ar 3 is the same or different and independently represents an optionally substituted aryl or heteroaryl; each E is further optionally substituted with at least one additional substituent; n is an integer from 0 to 3; and wherein the second repeat unit and optionally further repeat units are selected from optionally substituted phenyl, fluorene, spirobifluorene, indenofluorene, heteroaryl and/or dihydrophenanthrene and with the further proviso that when E is an unsubstituted atom, then the second repeat unit is directly conjugated to the first repeat unit.