Organic semiconducting layers

1. An organic semiconducting layer formulation, comprising an organic binder which has a permittivity, ∈, at 1,000 Hz of 3.3 or less; and a polyacene compound of formula 9

wherein R 2 , R 3 , R 7 , R 8 , R 15 , R 16 , and R 17 each independently is the same or different and each independently represents: H; an optionally substituted C 1 -C 40 carbyl or hydrocarbyl group; an optionally substituted C 1 -C 40 alkoxy group; an optionally substituted C 6 -C 40 aryloxy group; an optionally substituted C 7 -C 40 alkylaryloxy group; an optionally substituted C 2 -C 40 alkoxycarbonyl group; an optionally substituted C 7 -C 40 aryloxycarbonyl group; a cyano group (—CN); a carbamoyl group (—C(═O)NH 2 ); a haloformyl group (—C(═O)—X, wherein X represents a halogen atom); a formyl group (—C(═O)—H); an isocyano group; an isocyanate group; a thiocyanate group or a thioisoeyanate group; an optionally substituted amino group; an hydroxy group; a nitro group; a CF 3 group; a halo group; or an optionally substituted silyl group; and wherein independently each pair of R 2 and R 3 , R 7 and R 8 , R 15 and R 16 , and R 16 and R 17 is optionally cross-bridged with each other to form a C 4 -C 40 saturated or unsaturated ring, which saturated or unsaturated ring is optionally interrupted by an oxygen atom, a sulphur atom or a group shown by formula: —N(R a )— (wherein R a is a hydrogen atom or a hydrocarbon group), and is optionally substituted; wherein A represents silicon or germanium, and wherein one or more of the carbon atoms of the polyacene skeleton is optionally substituted by a heteroatom which is N, P, As, O, S, Se or Te,

wherein at least one pair of R 2 and R 3 , and R 7 and R 8 , is cross-bridged with each other to form a C 4 -C 40 saturated or unsaturated ring that is interrupted by an oxygen atom, a sulphur atom or a group shown by formula: —N(R a )— (wherein R a is a hydrogen atom or a hydrocarbon group) and is optionally substituted.

2. An organic semiconducting layer formulation as claimed in claim 1 , wherein the compound of formula 9 is of Formula 9A or its syn-isomer or formula 9B or its anti-isomer:

wherein

R 19 and R 20 each independently is an optionally substituted, optionally unsaturated C 1-40 carbyl or hydrocarbyl group,

or R 19 and R 20 either together with the carbon atoms to which they are attached or independently in combination with a substituent on a suitably adjacent atom form an optionally substituted C 4 -C 40 saturated or unsaturated ring optionally interrupted by one or more oxygen or sulphur atoms or a group represented by Formula —N(R a ), wherein R a is a hydrogen atom or a hydrocarbon group,

or R 19 and R 20 are the same substituent and comprise hydrogen or a saturated or unsaturated C 1-4 -alkyl group,

R 15 , R 16 , R 17 are the same or different and are as defined for the compound of formula 9, and one or more of the ring positions on the compound is optionally substituted;

wherein R 15 , R 16 , R 17 are the same or different and are as defined for the compound of formula 9, and one or more of the ring positions on the compound is optionally substituted.

3. An organic semiconducting layer formulation as claimed in claim 1 , wherein the organic binder resin has a permittivity at 1,000 Hz of less than 3.0.

4. An organic semiconducting layer formulation as claimed in claim 1 , wherein the organic binder resin has a permittivity at 1,000 Hz greater than 1.7.

5. An organic semiconducting layer formulation as claimed in claim 1 , wherein the organic binder resin is an insulating binder.

6. An organic semiconducting layer formulation as claimed in claim 1 , wherein the organic binder resin is an insulating binder which is poly(α-methylstyrene), polyvinylcinnamate, poly(4-vinylbiphenyl), poly(4-methylstyrene) or linear olefin and cycloolefin(norbornene)copolymer.

7. An organic semiconducting layer formulation as claimed in claim 1 , wherein the organic binder resin is a semiconductor binder.

8. An organic semiconducting layer formulation as claimed in claim 1 , wherein the organic binder resin is a semiconductor binder which comprises a number average molecular weight (M n ) of at least 1500-2000.

9. An organic semiconducting layer formulation as claimed in claim 1 , wherein the organic binder resin is a semiconductor binder which is poly(9-vinylcarbazole) or a triarylamine compound of the following formula

wherein n=10.7.

10. An organic semiconducting layer formulation as claimed in claim 1 , wherein the formulation further comprises a solvent.

11. An organic semiconducting layer formulation as claimed in claim 1 , wherein the formulation further comprises a solvent which is xylene(s), toluene, tetralin or odichlorobenzene.

12. An organic semiconducting layer formulation as claimed in claim 1 , wherein the ratio of polyacence compound to binder is 20:1 to 1:20 by weight.

13. An organic semiconducting layer formulation as claimed in claim 1 , which has a solids content of 0.1 to 10% by weight.

14. An organic semiconducting layer formulation as claimed in claim 2 , wherein in the compound of Formula 9A

R 2 and R 3 and/or R 7 and R 8 together with the carbon atom to which they are attached form a C 4 -C 40 saturated or unsaturated ring, that is optionally interrupted by one or more oxygen or sulphur atoms or by a group represented by the formula —N(R a ) (wherein R a is a hydrogen atom or a hydrocarbon group), that is optionally substituted.

15. An organic semiconducting layer formulation as claimed in claim 2 , wherein in the compound of Formula 9A

R 2 and R 3 and/or R 7 and R 3 together with the carbon atom to which they are attached form a C 4 -C 10 unsaturated ring that is interrupted by one or more oxygen atoms, that is optionally substituted.

16. An organic semiconducting layer formulation as claimed in claim 14 , wherein in the compound of Formula 9A

one or more of the carbon atoms of the polyacene skeleton is substituted by a heteroatom which is N, P, As, O, S, Se or Te.

17. An organic semiconducting layer formulation as claimed in claim 14 , wherein in the compound of Formula 9A

R 2 and R 3 and/or R 7 and R 8 together with the carbon atom to which they are attached form a C 4 -C 10 unsaturated ring that is interrupted by one or more oxygen atoms, which is substituted, wherein the substituents are selected from silyl, sulpho, sulphonyl, formyl, amino, imino, nitrilo, mercapto, cyano, nitro Cl, Br, or F.

18. An organic semiconducting layer formulation as claimed in claim 13 , wherein in the compound of Formula 9A

R 2 and R 3 and/or R 7 and R 8 together with the carbon atom to which they are attached form a C 4 -C 10 unsaturated ring that is interrupted by one or more sulphur atoms, that is optionally substituted.

19. An organic semiconducting layer formulation as claimed in claim 17 , wherein in the compound of Formula 9A

one or more of the carbon atoms of the polyacene skeleton is substituted by a heteroatom which is N, P, As, O, S, Se or Te.

20. An organic semiconducting layer formulation as claimed in claim 17 , wherein in the compound of Formula 9A

R 2 and R 3 and/or R 7 and R 8 together with the carbon atom to which they are attached form a C 4 -C 10 unsaturated ring that is interrupted by one or more sulphur atoms, which is substituted, wherein the substituents are silyl, sulpho, sulphonyl, formyl, amino, imino, nitrilo, mercapto, cyano, nitro, Cl, Br or F.

21. An organic semiconducting layer formulation as claimed in claim 2 , wherein in the compound of Formula 9A

R 2 and R 3 and/or R 7 and R 8 together with the carbon atom to which they are attached form a C 4 -C 10 saturated or unsaturated ring that is interrupted by a group represented by the formula N(R a ) (wherein R a is a hydrogen atom or a hydrocarbon group), which is optionally substituted.

22. An organic semiconducting layer formulation as claimed in claim 20 , wherein in the compound of Formula 9A

one or more of the carbon atoms of the polyacene skeleton is substituted by a heteroatom which is N, P, As, O, S, Se or Te.

23. An organic semiconducting layer formulation as claimed in claim 20 , wherein in the compound of Formula 9A

R 2 and R 3 and/or R 7 and R 8 together with the carbon atom to which they are attached form a C 4 -C 10 saturated or unsaturated ring that is interrupted by a group represented by the formula —N(R a ) (wherein R a is a hydrogen atom or a hydrocarbon group), which is substituted, wherein the substituents are silyl, sulpha, sulphonyl, formyl, amino, imino, nitrilo, mercapto, cyano, nitro Cl, Br or F.

24. An organic semiconducting layer formulation as claimed in claim 2 , wherein in the compound of Formula 9B

one or more of the carbon atoms of the polyacene skeleton is substituted by a heteratom which is N, P, As, O, S, Se or Te.

25. An organic semiconducting layer formulation as claimed in claim 24 , wherein in the compound of Formula 9B

R 19 and R 20 are each independently optionally substituted, saturated or unsaturated, cyclic or acyclic C 1-40 carbyl or hydrocarbyl groups or F, Cl or Br.

26. An organic semiconducting layer formulation as claimed in claim 25 , wherein in the compound of Formula 9B

the carbyl or hydrocarbyl groups are each independently a C 1 -C 40 alkyl group, a C 2-40 alkenyl group, a C 2 -C 40 alkynyl group, a C 3 -C 40 alkyl group, a C 4 -C 40 alkyldienyl group, a C 4 -C 40 polyenyl group, a C 6 -C 18 aryl group, a C 6 -C 40 alkylaryl group, a C 6 -C 40 arylalkyl group, a C 4 -C 40 cycloalkyl group, or a C 4 -C 40 cycloalkenyl group, all of which are optionally substituted.

27. An organic semiconducting layer formulation as claimed in claim 26 , wherein in the compound of Formula 9B

the carbyl or hydrocarbyl groups are each independently a C 1 -C 10 alkyl group, a C 2 -C 10 alkenyl group, a C 2 -C 10 alkynyl group, a C 3 -C 10 alkyl group, a C 4 -C 10 alkyldienyl group, a C 6 -C 12 aryl group or a C 4 -C 10 polyenyl group, all of which are optionally substituted.

28. An organic semiconducting layer formulation as claimed in claim 26 , wherein in the compound of Formula 9B

the substituents are silyl, sulpho, sulphonyl, formyl, amino, imino, nitrilo, mercapto, cyano, nitro, Cl, Br or F.

29. An organic semiconducting layer formulation as claimed in claim 26 , wherein in the compound of Formula 9

R 2 and R 3 and/or R 7 and R 8 together with the carbon atom to which they are attached form a C 4 -C 40 saturated or unsaturated ring, that is optionally interrupted by one or more oxygen or sulphur atoms or by a group represented by the formula —N(R a ) (wherein R a is a hydrogen atom or a hydrocarbon group), that is optionally substituted.

30. An organic semiconducting layer formulation as claimed in claim 29 , wherein in the compound of Formula 9

R 2 and R 3 and/or R 7 and R 8 together with the carbon atom to which they are attached form a C 4 -C 10 unsaturated ring that is interrupted by one or more oxygen atoms, that is optionally substituted.

31. An organic semiconducting layer formulation as claimed in claim 30 , wherein in the compound of Formula 9

one or more of the carbon atoms of the polyacene skeleton is substituted by a heteratom which is N, P, As, O, S, Se or Te.

32. An organic semiconducting layer formulation as claimed in claim 30 , wherein in the compound of Formula 9

R 2 and R 3 and/or R 7 and R 8 together with the carbon atom to which they are attached form a C 4 -C 10 unsaturated ring that is interrupted by one or more oxygen atoms, which is substituted, wherein the substituents are selected from silyl, sulpho, sulphonyl, formyl, amino, imino, nitrilo, mercapto, cyano, nitro Cl, Br, or F.

33. An organic semiconducting layer formulation as claimed in claim 29 , wherein in the compound of Formula 9 R 2 and R 3 and/or R 7 and R 8 together with the carbon atom to which they are attached form a C 4 -C 10 unsaturated ring that is interrupted by one or more sulphur atoms, that is optionally substituted.

34. An organic semiconducting layer formulation as claimed in claim 33 , wherein in the compound of Formula 9

one or more of the carbon atoms of the polyacene skeleton is substituted by a heteratom which is N, P, As, O, S, Se or Te.

35. An organic semiconducting layer formulation as claimed in claim 33 , wherein in the compound of Formula 9

R 2 and R 3 and/or R 7 and R 8 together with the carbon atom to which they are attached form a C 4 -C 10 unsaturated ring that is interrupted by one or more sulphur atoms, which is substituted, wherein the substituents are silyl, sulpho, sulphonyl, formyl, amino, imino, nitrilo, mercapto, cyano, nitro, Cl, Br or F.

36. An organic semiconducting layer formulation as claimed in claim 29 , wherein in the compound of Formula 9

R 2 and R 3 and/or R 7 and R 8 together with the carbon atom to which they are attached form a C 4 -C 10 saturated or unsaturated ring that is interrupted by a group represented by the formula —N(R a ) (wherein R a is a hydrogen atom or a hydrocarbon group), which is optionally substituted.

37. An organic semiconducting layer formulation as claimed in claim 36 , wherein in the compound of Formula 9

one or more of the carbon atoms of the polyacene skeleton is substituted by a heteratom which is N, P, As, O, S, Se or Te.

38. An organic semiconducting layer formulation as claimed in claim 36 , wherein in the compound of Formula 9

R 2 and R 3 and/or R 7 and R 8 together with the carbon atom to which they are attached form a C 4 -C 10 saturated or unsaturated ring that is interrupted by a group represented by the formula —N(R a ) (wherein R a is a hydrogen atom or a hydrocarbon group), which is substituted, wherein the substituents are silyl, sulpho, sulphonyl, formyl, amino, imino, nitrilo, mercapto, cyano, nitro Cl, Br or F.

39. In an electronic device, wherein the improvement comprises the presence of an organic semiconducting layer in said electronic device, which organic semiconducting layer comprises an organic semiconducting layer formulation as claimed in claim 1 .

40. A field effect transistor (FET), organic light emitting diode (OLED), photodetector, chemical detector, photovoltaic cell (PVs), capacitor sensor, logic circuit, display or memory device, comprising an organic semiconducting layer, which comprises an organic semiconducting layer formulation as claimed in claim 1 .

41. An OFET device, comprising an organic semiconducting layer formulation as claimed in claim 1 ,

wherein the binder is poly(α-methylstyrene), linear olefin and cycloolefin(norbornene)copolymer, poly(4-methylstyrene), polystyrene or polystyrene-co-α-methylstyrene; and

which formulation further comprises a solvent which is toluene, ethylcyclohexane, anisole or pxylene.

42. A process for preparing an organic semiconducting layer formulation as claimed in claim 1 , comprising (i) depositing on a substrate a liquid layer of a mixture which comprises the polyacene compound, the organic binder resin or precursor thereof and optionally a solvent, and (ii) forming from the liquid layer a solid layer which is the organic semiconducting layer.