Organic semiconductor doping process

1. A process for producing a p-doped organic semiconductor comprising treating an organic semiconductor with a protic ionic liquid,

wherein the organic semiconductor comprises a compound of formula (Vb)

and wherein each R 1 is the same or different and is a group selected from hydrogen, C 1-8 alkyl, C 2-8 alkenyl, C 2-8 alkynyl, C 1-8 alkoxy, hydroxyl, mono-C 1-8 alkylamino, di-C 1-8 alkylamino, amino, halide, cyano, nitro, and thiol; and

wherein the protic ionic liquid is not 1-ethyl-3-methylimidazolium-TFSI or 1-butyl-3-methylimidazolium-TFSI.

2. The process according to claim 1 wherein the protic ionic liquid is a compound of formula PA wherein P is a cation selected from H + , H 3 O + , an ammonium cation, an imidazolium cation, a pyridinium cation, a pyrrolidonium cation or an indolium cation; and wherein A is ClO 4 − , NO 3 − or an anion of formula (i), (ii), (iii) or (iv)

wherein each X is the same or different and is an electron withdrawing group, optionally wherein X is CF 3 or CF 2 CF 3 , or wherein A is bis(trifluoromethanesulfonyl)imide, bis(pentafluoroethanesulfonyl)imide, bis(perfluoropropanesulfonyl)imide, trifluoroacetate, or trifluoromethanesulfonate.

3. The process according to claim 2 wherein P is a cation selected from H + , H 3 O + , NR 4 + , NHR 3 + , NH 2 R 2 + , NH 3 R + or NH 4 + ,

wherein R is independently selected from C 1-8 alkyl, C 2-8 alkenyl or aryl; and

wherein R a , R b , and R c are independently selected from H, C 1-8 -alkyl, C 2-8 -alkenyl or aryl, and at least one of R a , R b , and R c is H.

4. The process according to claim 1 wherein the protic ionic liquid is selected from H-TFSI, 1-alkyl-3-methylimidazolium-TFSI, H-BETI, 1-alkyl-3-methylimidazolium-BETI, 1-methyl-3-methylimidazolium-TFSI, and 1-propyl-3-methylimidazolium-TFSI.

5. The process according to claim 1 wherein the amount of the protic ionic liquid is from 0.01 to 50 mol % relative to the amount of the organic semiconductor.

6. A process according to claim 1 wherein the amount of the protic ionic liquid is from 5 to 30 mol % relative to the amount of the organic semiconductor.

7. A process for producing a layer of a p-doped organic semiconductor comprising disposing on a substrate an organic semiconductor and a protic ionic liquid,

wherein the organic semiconductor comprises a compound of formula (Vb)

and wherein each R 1 is the same or different and is a group selected from hydrogen, C 1-8 alkyl, C 2-8 alkenyl, C 2-8 alkynyl, C 1-8 alkoxy, hydroxyl, mono-C 1-8 alkylamino, di-C 1-8 alkylamino, amino, halide, cyano, nitro, and thiol; and

wherein the protic ionic liquid is not 1-ethyl-3-methylimidazolium-TFSI or 1-butyl-3-methylimidazolium-TFSI.

8. The process according to claim 7 wherein the process comprises

(a) disposing on a substrate a solvent, an organic semiconductor and a protic ionic liquid; and

(b) removing the solvent.

9. The process according to claim 8 wherein the process comprises

(a) disposing on a substrate a composition comprising a solvent, an organic semiconductor and a protic ionic liquid; and

(b) removing the solvent.

10. The process according to claim 7 wherein the organic semiconductor comprises 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9′-Spirobifluorene (Spiro-OMeTAD).

11. The process according to claim 7 wherein the protic ionic liquid is selected from H-TFSI, 1-alkyl-3-methylimidazolium-TFSI, H-BETI, 1-alkyl-3-methylimidazolium-BETI, 1-methyl-3-methylimidazolium-TFSI, and 1-propyl-3-methylimidazolium-TFSI

12. The process according to claim 9 wherein the process further comprises producing the composition comprising the solvent, the organic semiconductor and the protic ionic liquid by treating a composition comprising the organic semiconductor and a first solvent with a composition comprising the protic ionic liquid and a second solvent.

13. The process according to claim 12 wherein the first solvent is chlorobenzene and the second solvent is acetonitrile.

14. The process according to claim 9 wherein the composition disposed on the substrate further comprises LiTFSI and/or tert-butyl pyridine.

15. The process according to claim 14 wherein the composition comprises from 1 to 40 mol % LiTFSI and from 50 to 150 mol % tert-butyl pyridine relative to the amount of the organic semiconductor.

16. The process according to claim 8 wherein the solvent comprises acetonitrile and/or chlorobenzene.

17. The process according to claim 7 wherein the substrate comprises an electrode material or a semiconductor material or a mesoporous layer of a semiconductor material or a mesoporous layer of a dielectric material.

18. The layer of a p-doped organic semiconductor produced according to the process of claim 7 .

19. A layer of a p-doped organic semiconductor, wherein the layer comprises an organic semiconductor and a protic ionic liquid, and

the organic semiconductor comprises a compound of formula (Vb)

and wherein each R 1 is the same or different and is a group selected from hydrogen, C 1-8 alkyl, C 2-8 alkenyl, C 2-8 alkynyl, C 1-8 alkoxy, hydroxyl, mono-C 1-8 alkylamino, di-C 1-8 alkylamino, amino, halide, cyano, nitro, and thiol; and

wherein the protic ionic liquid is not 1-ethyl-3-methylimidazolium-TFSI or 1-butyl-3-methylimidazolium-TFSI.

20. The layer according to claim 19 wherein the organic semiconductor comprises 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9′-Spirobifluorene (Spiro-OMeTAD) and/or wherein the protic ionic liquid is selected from H-TFSI, 1-alkyl-3-methylimidazolium-TFSI, H-BETI, and 1-alkyl-3-methylimidazolium-BETI, 1-methyl-3-methylimidazolium-TFSI, and 1-propyl-3-methylimidazolium-TFSI

21. A process for producing a semiconductor device comprising

a step of producing a p-doped organic semiconductor by a process comprising treating an organic semiconductor with a protic ionic liquid; or

a step of producing a layer of a p-doped organic semiconductor by a process comprising disposing on a substrate an organic semiconductor and a protic ionic liquid,

wherein the organic semiconductor comprises a compound of formula (Vb)

and wherein each R 1 is the same or different and is a group selected from hydrogen, C 1-8 alkyl, C 2-8 alkenyl, C 2-8 alkynyl, C 1-8 alkoxy, hydroxyl, mono-C 1-8 alkylamino, di-C 1-8 alkylamino, amino, halide, cyano, nitro, and thiol; and

wherein the protic ionic liquid is not 1-ethyl-3-methylimidazolium-TFSI or 1-butyl-3-methylimidazolium-TFSI.

22. The process according to claim 21 wherein the process further comprises the steps of:

(a) disposing on a first electrode material at least one layer of a semiconductor material to produce a resulting substrate comprising the first electrode material and at least one layer of the semiconductor material;

(b) sensitizing the resulting substrate to produce a sensitized substrate; and

(c) producing the layer of a p-doped organic semiconductor on the sensitized substrate, or producing the p-doped organic semiconductor by a process comprising treating the organic semiconductor with the protic ionic liquid and forming the layer of the p-doped organic semiconductor on the sensitized substrate.

23. The process according to claim 22 wherein (a) comprises disposing on a first electrode material a compact layer of a semiconductor material and/or a mesoporous layer of a semiconductor material.

24. The process according to claim 22 wherein the first electrode material comprises a transparent conducting oxide.

25. The process according to claim 22 wherein (b) comprises treating the resulting substrate comprising the first electrode material and the at least one layer of a semiconductor material with a dye or a semiconducting perovskite.

26. The process according to claim 22 which further comprises:

(d) disposing a second electrode material on the layer of a p-doped organic semiconductor.

27. The process according to claim 21 wherein the semiconductor device is any one of an optoelectronic device, a photovoltaic device, a solar cell, a photo detector, a light-sensitive transistor, a capacitor, a super-capacitor, a phototransistor, a solid-state triode, a battery, a battery electrode, a light-emitting device, a light-emitting diode, a dye-sensitized solar cell, a perovskite-sensitized solar cell, a quantum dot sensitized solar cell, an absorber cell or a meso-super structured solar cell.

28. The semiconductor device produced according to the process of claim 21 .

29. A semiconductor device comprising a layer of a p-doped organic semiconductor, wherein the layer of a p-doped organic semiconductor comprises an organic semiconductor and a protic ionic liquid, and

the organic semiconductor comprises a compound of formula (Vb)

and wherein each R 1 is the same or different and is a group selected from hydrogen, C 1-8 alkyl, C 2-8 alkenyl, C 2-8 alkynyl, C 1-8 alkoxy, hydroxyl, mono-C 1-8 alkylamino, di-C 1-8 alkylamino, amino, halide, cyano, nitro, and thiol; and

wherein the protic ionic liquid is not 1-ethyl-3-methylimidazolium-TFSI or 1-butyl-3-methylimidazolium-TFSI.