Organic semiconducting polymers

A polymer comprising one or more repeating units of formula I

• wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings,
• each pair of U1 and U2 is attached to two directly adjacent C atoms in a ring Ar1, Ar2 or Ar3 respectively, and in each of said pairs of U1 and U2 one of U1 and U2 is a single bond and the other is CR1R2, SiR1R2, GeR1R2, C═CR1R2, C═O or NR1, so that each pair of U1 and U2 is forming a five-membered unsaturated ring together with the C atoms to which they are attached,
• RT1, RT2 a group of formula T
• Z1, Z2 C═O, C═CX1X2, SO2,
• X1, X2 CN, C(═O)Ra,
• Ar1, Ar2, Ar3 arylene or heteroarylene which has from 5 to 20 ring atoms, is mono- or polycyclic, optionally contains fused rings, and is unsubstituted or substituted by one or more identical or different groups L,
• Ar4, Ar5 —CY1═CY2—, —C≡C—, or arylene or heteroarylene which has from 5 to 20 ring atoms, is mono- or polycyclic, optionally contains fused rings, and is unsubstituted or substituted by one or more identical or different groups L,
• Ar6 arylene or heteroarylene which has from 5 to 20 ring atoms, is mono- or polycyclic, optionally contains fused rings, and is unsubstituted or substituted by one or more identical or different groups L,
• Y1, Y2H, F, Cl or CN,
• R1, R2H, F, Cl, CN, or straight-chain, branched or cyclic alkyl with 1 to 30, preferably 1 to 20, C atoms, in which one or more CH2 groups are each optionally replaced by —O—, —S—, —C(═O)—, —C(═S)—, —C(═O)—O—, —O—C(═O)—, —NR0—, —SiR0R00—, —CF2—, —CR0═CR00—, —CY1═CY2— or —C≡C— in such a manner that O and/or S atoms are not linked directly to one another, and in which one or more H atoms are each optionally replaced by F, Cl, Br, I or CN, and in which one or more CH2 or CH3 groups are each optionally replaced by a cationic or anionic group, or aryl, heteroaryl, arylalkyl, heteroarylalkyl, aryloxy or heteroaryloxy, wherein each of the aforementioned cyclic groups has 5 to 20 ring atoms, is mono- or polycyclic, optionally contains fused rings, and is unsubstituted or substituted by one or more identical or different groups L,
• and the pair of R1 and R2, together with the C, Si or Ge atom to which they are attached, may also form a spiro group with 5 to 20 ring atoms which is mono- or polycyclic, optionally contains fused rings, and is unsubstituted or substituted by one or more identical or different groups L,
• Ra R0 or aryl or heteroaryl, each having from 4 to 30 ring atoms, optionally containing fused rings and being unsubstituted or substituted with one or more groups L,
• L F, Cl, —NO2, —CN, —NC, —NCO, —NCS, —OCN, —SCN, R0, OR0, SR0, —C(═O)X0, —C(═O)R0, —C(═O)—OR0, —O—C(═O)—R0, —NH2, —NHR0, —NR0R00, —C(═O)NHR0, —C(═O)NR0R00, —SO3R0, —SO2R0, —OH, —CF3, —SF5, or optionally substituted silyl, or carbyl or hydrocarbyl with 1 to 30, preferably 1 to 20 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, preferably F, —CN, R0, —OR0, —SR0, —C(═O)—R0, —C(═O)—OR0, —O—C(═O)—R0, —O—C(═O)—OR0, —C(═O)—NHR0, or —C(═O)—NR0R00,
• L′ H or one of the meanings given for L,
• R0, R00H or straight-chain or branched alkyl with 1 to 20, preferably 1 to 12, C atoms that is optionally fluorinated,
• X0 halogen, preferably F or Cl,
• a 0, 1, 2 or 3,
• b, c 0, 1, 2 or 3,
• characterized in that, if a>0, Ar1 contains at least one thiophene ring.