Diketopyrrolopyrrole polymers for use in organic field effect transistors
The present invention relates to polymers comprising a repeating unit of the formula I, or III and their use as organic semiconductor in organic devices, especially an organic field effect transistor (OFET), or a device containing a diode and/or an organic field effect transistor. The polymers according to the invention have excellent solubility in organic solvents and excellent film-forming properties. In addition, high efficiency of energy conversion, excellent field-effect mobility, good on/off current ratios and/or excellent stability can be observed, when the polymers according to the invention are used in organic field effect transistors.
1. 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.
2. The polymer according to claim 1 , comprising one or more repeating unit(s) of the formula
wherein
a is an integer of 1 to 5,
b is an integer of 2, or 3, b′ is an integer of 2, b″ is an integer of 3,
one of X 1 and X 2 is N and the other is CH, and
R 1 and R 2 are independently hydrogen, or a C 8 -C 36 alkyl group.
3. The polymer according to claim 1 , comprising one or more repeating unit(s) of the formula
wherein
R 1 and R 2 are independently a C 8 -C 36 alkyl group.
4. The polymer according to claim 1 , wherein a is an integer of 1 to 3.
5. The polymer according to claim 1 , comprising one or more repeating unit(s) of the formula
wherein
R 1 ′ and R 2 ′ are independently a C 8 -C 36 alkyl group.
6. The polymer according to claim 1 , wherein R 1 , R 2 , R 1 ′ and R 2 ′ are a branched C 12 -C 24 alkyl group.
7. The polymer according to claim 1 , which is a copolymer of formula
wherein
R 1 , R 2 , R 1 ′ and R 2 ′ are a branched C 8 -C 36 alkyl group, or a copolymer of formula
having a Mw of 51,500 and a polydispersity of 2.0 (measured by HT-GPC).
8. The polymer according to claim 3 , comprising repeating units of the formula
wherein
R 1 and R 2 are independently a C 8 -C 36 alkyl group.
9. An organic semiconductor material, layer or component, comprising a polymer according to claim 1 .
10. A semiconductor device, comprising a polymer according to claim l, or an organic semiconductor material, layer or component comprising a polymer according to claim 1 .
11. The semiconductor device according to claim 10 , which is an organic field effect transistor (OFET).
12. Process for the preparation of an organic semiconductor device, which process comprises applying a solution and/or dispersion of a polymer according to claim 1 in an organic solvent to a suitable substrate and removing the solvent.
13. A method of using the polymer according to claim 1 , or the organic semiconductor material, layer or component comprising a polymer according to claim l in OFETs.
14. An integrated circuit comprising an organic field effect transistor according to claim 11 .
15. A polymer according to claim 7 , wherein R 1 , R 2 , R 1 ′ and R 2 ′ are a branched C 12 -C 24 alkyl group.
16. The semiconductor device according to claim 11 , which is an ambipolar organic field effect transistor (OFET), comprising p-type and n-type behavior.
17. The polymer according to claim 2 , comprising one or more repeating unit(s) of the formula
wherein
a is an integer of 1 to 5, and
R 1 and R 2 are independently hydrogen or a C 8 -C 36 alkyl group.
18. The polymer according to claim 2 , comprising one or more repeating unit(s) of the formula
wherein
R 1 and R 2 are independently hydrogen or a C 8 -C 36 alkyl group.
19. The polymer according to claim 1 , wherein Ar l , Ar 1′ , Ar 3 and Ar 3′ are a group of formula
20. The polymer according to claim 1 , wherein Ar 2 is a group of formula