Patent ID: 8912305

Claim:
A polymer comprising one or more repeating unit(s) of the formula wherein a is an integer of 1 to 5, b is an integer of 1 to 3, c is an integer of 1 to 3, d is an integer 2 or 3, e is an integer 2 or 3, the sum of a, b and c is equal to or smaller than 7, Ar 1 , Ar 1′ , Ar 3 and Ar 3′ are independently of each other a group of formula or a group —Ar 4 —Ar 5 —[Ar 6 ] f— , Ar 4 is a group of formula Ar 5 and Ar 6 have independently of each other the meaning of Ar 1 , f is 0, or an integer 1, Ar 2 is a group of formula one of X 1 and X 2 is N and the other is CH, and R 1 , R 2 , R 1′ and R 2′ may be the same or different and are selected from hydrogen, a C 1 -C 100 alkyl group, a C 6 -C 24 aryl, which can be substituted one to three times with C 1 -C 8 alkyl, C 1 -C 8 thioalkoxy, and/or C 1 -C 8 alkoxy, or pentafluorophenyl; wherein the polymers have a weight average molecular weight of 4,000 Daltons or greater; with the proviso that polymers of formula having a molecular weight below 10000 are excluded, and with the further proviso that polymers of formula having a molecular weight below 10000 are excluded; and with the further proviso that the following polymer having a molecular weight of 28589 g/mol and a λ onset of 904 (film) is excluded.