A mixture for use in forming a solution, the mixture comprising a p-type semiconductor, an n-type semiconductor, and one or more nanoparticles, wherein the nanoparticles comprise silica, zeolite, carbon, activated carbon silsesquioxane, polysilsesquioxane, clay, or any combination of the aforementioned, characterised in that the nanoparticles are hydrophobic and in that the nanoparticles are substituted by one or more identical or different groups R, wherein R is CN or an alkyl group with 1 to 50 C atoms, which is straight-chain, branched or cyclic, and in which one or more CH 2 groups are optionally replaced by -O-, -S-,-C(=O)-,-C(=S)-, -C(=O)-O-, -O-C(=O)-, -NR 0 -, -C(=O)-NR 0 -, -NR 0 -C(=O)-, -SiR 0 R 00 -, -CF 2 -, -CR 0 =CR 00 -,-CR 0 =N-, -N=N- or-C=C- in such a manner that O and/or S atoms are not linked directly to one another, and/or in which one or more H atoms are optionally replaced by F, CI, Br, I or CN and/or in which one or more H is replaced by a cationic or anionic group, or R is a saturated or unsaturated, non-aromatic carbo- or heterocyclic group, or an aryl, heteroaryl, aryloxy or heteroaryloxy group, wherein each of the aforementioned cyclic groups has 5 to 20 ring atoms, is mono- or polycyclic, does optionally contain fused rings, and is optionally substituted by one or more identical or different groups L, L is halogen, -CN, -NC, -NCO, -NCS, -OCN, -SCN,-C(=O)NR 0 R 00, -C(=O)X 0, -C(=O)R 0, -NH 2, -NR 0 R 00, -SH,-SR 0, -SO 3 H, -SO 2 R 0, -OH, -NO 2, -CF 3, -SF 5, optionally substituted silyl, or carbyl or hydrocarbyl with 1 to 40 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, preferably alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkylcarbonyloxy, alkoxycarbonyl or alkoxycarbonyloxy with 1 to 20 C atoms that is optionally fluorinated, R 0, R 00 are independently of each other H or alkyl with 1 to 12 C atoms, or a silyl group with 1 to 20 Si atoms that is optionally alkylated, X 0 is halogen, preferably F, Cl or Br, and in that the n-type semiconductor and the nanoparticles contained in the mixture are not chemically linked to each other but are separate mixture components. R is CN or an alkyl group with 1 to 50 C atoms, which is straight-chain, branched or cyclic, and in which one or more CH 2 groups are optionally replaced by -O-, -S-,-C(=O)-,-C(=S)-, -C(=O)-O-, -O-C(=O)-, -NR 0 -, -C(=O)-NR 0 -, -NR 0 -C(=O)-, -SiR 0 R 00 -, -CF 2 -, -CR 0 =CR 00 -,-CR 0 =N-, -N=N- or-C=C- in such a manner that O and/or S atoms are not linked directly to one another, and/or in which one or more H atoms are optionally replaced by F, CI, Br, I or CN and/or in which one or more H is replaced by a cationic or anionic group, or R is a saturated or unsaturated, non-aromatic carbo- or heterocyclic group, or an aryl, heteroaryl, aryloxy or heteroaryloxy group, wherein each of the aforementioned cyclic groups has 5 to 20 ring atoms, is mono- or polycyclic, does optionally contain fused rings, and is optionally substituted by one or more identical or different groups L, L is halogen, -CN, -NC, -NCO, -NCS, -OCN, -SCN,-C(=O)NR 0 R 00, -C(=O)X 0, -C(=O)R 0, -NH 2, -NR 0 R 00, -SH,-SR 0, -SO 3 H, -SO 2 R 0, -OH, -NO 2, -CF 3, -SF 5, optionally substituted silyl, or carbyl or hydrocarbyl with 1 to 40 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, preferably alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkylcarbonyloxy, alkoxycarbonyl or alkoxycarbonyloxy with 1 to 20 C atoms that is optionally fluorinated, R 0, R 00 are independently of each other H or alkyl with 1 to 12 C atoms, or a silyl group with 1 to 20 Si atoms that is optionally alkylated, X 0 is halogen, preferably F, Cl or Br, and in that the n-type semiconductor and the nanoparticles contained in the mixture are not chemically linked to each other but are separate mixture components.