Patent ID: 8598304

Claim:
A poly(5,5′-bis(thiophen-2-yl)-benzo[2,1-b;3,4-b]dithiophene), comprising as a repeating unit at least one group of formula (I) wherein R is independently a) a C 1-20 alkyl group, b) a C 2-20 alkenyl group, c) a C 2-20 alkynyl group, d) a C 1-20 alkoxy group, e) a —Y—C 3-10 cycloalkyl group, f) a —Y—C 6-14 aryl group, g) a —Y-3-12 membered cycloheteroalkyl group, or h) a —Y-5-14 membered heteroaryl group, wherein each of the C 1-20 alkyl group, the C 2-20 alkenyl group, the C 2-20 alkynyl group, the C 3-10 cycloalkyl group, the C 6-14 aryl group, the 3-12 membered cycloheteroalkyl group, and the 5-14 membered heteroaryl group is optionally substituted with 1-4 R 1 groups, R 1 is independently a) a S(O) m —C 1-20 alkyl group, b) a S(O) m —OC 1-20 alkyl group, c) a S(O) m —OC 6-14 aryl group, d) a C(O)—OC 1-20 alkyl group, e) a C(O)—OC 6-14 aryl group, f) a C 1-20 alkyl group, g) a C 2-20 alkenyl group, h) a C 2-20 alkynyl group, i) a C 1-20 alkoxy group, j) a C 3-10 cycloalkyl group, k) a C 6-14 aryl group, l) a 3-12 membered cycloheteroalkyl group, or m) a 5-14 membered heteroaryl group, Y is independently a divalent C 1-6 alkyl group, or a covalent bond; and m is independently 0, 1, or 2, and having a number average molecular weight M n in a range of from 5,000 to 200,000 g/mol.