Organic semiconductor composition comprising a liquid medium

1. A composition, comprising:

A) at least one organic semiconductor which is an rylene compound of formula (I.a):

wherein:

n is 1 or 2,

R a and R b are independently hydrogen or in each case an optionally substituted alkyl, alkenyl, alkadienyl, alkynyl, cycloalkyl, bicycloalkyl, cycloalkenyl, heterocycloalkyl, aryl, or heteroaryl group,

R n1 , R n2 , R n3 and R n4 are independently of one another selected from the group consisting of hydrogen, F, Cl, Br and CN, such that at least one of R n1 , R n2 , R n3 and R n4 is not hydrogen; and

B) at least one compound of formula (II.1) that is liquid at 20° C. and 1013 mbar:

wherein:

X 1 and X 2 represent *—(C═O)—O—, where * is the point of linkage to the aromatic carbocycle, and

R c and R d are independently selected from the group consisting of unbranched and branched C 1 -C 12 -alkyl and C 2 -C 12 -alkenyl.

2. The composition according to claim 1 , wherein R a and R b are independently selected from the group consisting of hydrogen, linear C 1 -C 30 -alkyl, branched C 3 -C 30 -alkyl, perfluoro-C 1 -C 30 -alkyl, 1H,1H-perfluoro-C 2 -C 30 -alkyl, 1H,1H,2H,2H-perfluoro-C 3 -C 30 -alkyl, a radical of the formula G.1, a radical of the formula G.2 and a radical of the formula G.3:

where:

# represents the bonding side to a nitrogen atom,

B where present, is a C 1 -C 10 -alkylene group which may be interrupted by one or more nonadjacent groups which are selected from the group consisting of —O— and —S—,

y is 0 or 1,

R m is independently selected from the group consisting of C 1 -C 30 -alkyl, C 1 -C 30 -fluoroalkyl, fluorine, chlorine, bromine, NE 3 E 4 , nitro and cyano, where E 3 and E 4 , independently of one another, are hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl,

R n is independently C 1 -C 30 -alkyl, and

x in formulae G.2 and G.3 is 1, 2, 3, 4 or 5.

3. The composition according to claim 1 , wherein R a and R b are selected from the group consisting of radicals of formulae (III.1), (III.2) and (III.3):

wherein:

# is a bonding site,

in the formula (III.1) R e and R f are independently C 1 - to C 27 -alkyl, where the sum of the carbon atoms of the R e and R f radicals is an integer from 2 to 28,

in the formula (III.2) R g and R h are independently C 1 - to C 28 -alkyl, where the sum of the carbon atoms of the R g and R h radicals is an integer from 2 to 29, and

in the formula (III.3) R i , R k and R l are independently C 1 - to C 27 -alkyl, where the sum of the carbon atoms of the R i , R k and R l radicals is an integer from 3 to 29.

4. The composition according to claim 1 , wherein R a and R b have the same meaning.

5. The composition according to claim 1 , wherein the component A) is a compound of formula (I.a1):

wherein:

R a and R b are defined as above,

R 12 and R 23 are independently selected from the group consisting of F, Cl, Br, CN, and

R 11 , R 13 , R 14 , R 21 , R 22 and R 24 are hydrogen.

6. The composition according to claim 1 , wherein the compound B) satisfies:

a Hansen solubility parameter (delta D) ranging from 15 to 20,

a Hansen solubility parameter (delta P) ranging from 7 to 12,

a Hansen solubility parameter (delta H) ranging from 3.5 to 5.5, and

a boiling point at 1013.25 mbar of at least 100° C.

7. The composition according to claim 1 , wherein R c and R d are independently selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec.-butyl, tert.-butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, isononyl, isodecyl, 2-propylheptyl, n-undecyl and isoundecyl.

8. The composition according to claim 1 , wherein the compound B) is selected from the group consisting of dimethylphthalate, diethylphthalate, di(n-propyl)phthalate, di(n-butyl)phthalate, diallylphthalate and mixtures thereof.

9. The composition according to claim 1 , wherein the organic semiconductor A) has a solubility in component B) at 20° C. of at least 0.01 mg/ml.

10. The composition according to claim 1 , further comprising:

C) a cosolvent selected from the group consisting of an organic solvent different from the compound B) and mixtures thereof.

11. The composition according to claim 10 , wherein the cosolvent C) is selected from the group consisting of:

aliphatic, cycloaliphatic and aromatic hydrocarbons,

aromatic ethers,

open chain aliphatic ethers, polyethers, ether alcohols and cyclic ethers,

ketones,

esters,

aliphatic and cycloaliphatic alcohols,

benzene based alcohols,

halogenated aromatic compounds,

thiophenols and alkylthio-substituted benzenes,

aromatic compounds comprising a phenyl group fused to a 5-, 6-, or 7-membered cycloheteroalkyl group,

5-membered heteroaryl compounds and benzo-fused 5-membered heteroaryl compounds,

aromatic carboxylic acids,

aromatic aldehydes,

trifluoromethyl-substituted benzene compounds,

cyano-substituted or isocyano-substituted benzene compounds,

nitro-substituted benzene compounds,

phenyl sulfones,

6-membered heteroaryl compounds and benzofused 6-membered heteroaryl compounds,

5-membered heteroaryl compounds and benzofused 5-membered heteroaryl compounds,

aprotic polar solvents, and

mixtures thereof.

12. The composition according to claim 10 , wherein the organic semiconductor A) has a solubility in a mixture of components B) and C) at 20° C. of at least 0.01 mg/ml.

13. The composition according to claim 1 , further comprising:

a viscosity-modifying additive.

14. A process, comprising applying the composition of claim 1 to at least a portion of the surface of a substrate to allow deposition of the at least one organic semiconductor A) on the substrate.

15. The process according to claim 14 , wherein the composition is applied to the surface of the substrate by printing.

16. The process according to claim 14 , wherein the surface of the substrate is a substrate coated with a dielectric.

17. The process according to claim 14 , wherein:

the surface of the substrate or, if present, a dielectric coating on the substrate, is subjected to a surface modification prior to the application of the composition; and

a compound used for the surface modification is selected from the group consisting of silanes, phosphonic acids, carboxylic acids, hydroxamic acids, amines, phosphines, sulfur-comprising compounds and mixtures thereof.

18. The process according to claim 14 , which produces a device selected from the group consisting of organic field-effect transistors, electroluminescent arrangements, organic solar cells and photodetectors.

19. The composition according to claim 1 , wherein:

the at least one organic semiconductor is an rylene compound of formula (I.a) having the structure:

and

the at least one compound of formula (II) is dimethylphthalate.