Organic semiconductors

A Monomer of formula VI

• R9—Ar1-U-Ar2—R10 VI
• wherein
• U is a unit of formula I wherein
• wherein
• V1 and V2 are independently of each other O, S, Se or Te,
• X1 and X2 are independently of each other CR1R2, C═CR1R2, SiR1R2 or GeR1R2
• R, R1 and R2 independently of each other, and on each occurrence identically or differently, denote H, F, Cl, Br, CN, straight-chain, branched or cyclic alkyl, with 1 to 30 C atoms, in which one or more non-adjacent C atoms are optionally replaced by —O—, —S—, —C(O)—, —C(O)—O—, —O—C(O)—, —O—C(O)—O—, —C(S)—, —C(S)—O—, —O—C(S)—, —O—C(S)—O—, —C(O)—S—, —S—C(O)—, —O—C(O)—S—, —S—C(O)—O—, —S—C(O)—S—, —S—C(S)—S—, —O—C(S)—S—, —S—C(S)—O—, —C(S)—S—, —S—C(S)—, —NR0—, —SiR0R00—, —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 optionally replaced by F, Cl, Br, I or CN, or R1 and R2, independently of each other, and on each occurrence identically or differently, denote aryl, heteroaryl, aryloxy or heteroaryloxy with 4 to 20 ring atoms which is optionally substituted, or R1 and R2 together form an alicyclic group with 1 to 20 C atoms, which is optionally fluorinated or alkylated,
• Y1 and Y2 are independently of each other H, F, Cl or CN,
• R0 and R00 are independently of each other H or optionally substituted C1-40 carbyl or hydrocarbyl,
• Ar1, Ar2 are, on each occurrence identically or differently, and independently of each other, aryl or heteroaryl that is different from U, and is optionally substituted, and R9 and R10 independently of each other denote F, Br, Cl, —CH2Cl, —CHO, —CH═CH2, —SiR′R″R′″, —SnR′R″R′″, —BR′R″, —B(OR′)(OR″), —B(OH)2, —ZnCl, —MgCl, or —MgBr, wherein R′, R″and R′″ have independently of each other one of the meanings of R0 as defined above, and two of R′, R″ and R′″ may also form a ring together with the hetero atom to which they are attached.