Solutions of polymer semiconductors
View Patent ↗The present invention relates to a process for producing particle-free solutions of polymeric semiconductors and to their use for producing layers of polymeric semiconductors in polymeric organic light-emitting diodes (PLEDs), organic integrated circuits (O-ICs), organic field effect transistors (OFETs), organic thin film transistors (OTFTs), organic solar cells (O-SCs) or organic laser diodes (O-lasers).
1. A process for preparing solutions comprising polymeric organic semiconductors, which comprises the steps:
A) dissolution of at least one polymeric organic semiconductor in a suitable solvent (STARTING SOLUTION),
B) after-treatment of the STARTING SOLUTION from step A) (SOLUTION),
C) filtration of the SOLUTION from step B) by means of dead-end filtration and/or crossflow filtration and isolation of the filtered solution comprising at least one polymeric organic semiconductor (FILTERED SOLUTION).
2. The process as claimed in claim 1 , wherein a mixture of a plurality of polymeric organic semiconductors (polymer blend), and optionally in combination with one or more low molecular weight additives, is used in step A).
3. The process as claimed in claim 1 , characterized in that a solvent mixture is used in step A).
4. The process as claimed in claim 1 , wherein the polymeric organic semiconductor is dissolved in the solvent (step A) by action of shear forces.
5. The process as claimed in claim 1 , wherein the solution from step A) still comprises dispersion-like constituents.
6. The process as claimed in claim 1 , wherein the after-treatment of the solution from step A) is carried out by means of one or more mechanical after-treatment(s).
7. The process as claimed in claim 6 , characterized in that the mechanical after-treatment is carried out by means of ultrasound, a fast-running, high-shear dispersing stirrer and/or a disintegrator.
8. The process as claimed in claim 1 , wherein the solution obtained in step B) is prefiltered before the filtration in step C).
9. The process as claimed in claim 1 , wherein the solution obtained in step C) is filtered by means of further filtration methods.
10. The process as claimed in claim 1 , wherein the concentration/viscosity ratio of the FILTERED SOLUTION obtained in step C) is adjusted by addition of solvent or solvent mixture.
11. The process as claimed in claim 1 , wherein step A), step B) and/or step C), are carried out under an inert atmosphere.
12. The process as claimed in claim 10 , characterized in that the filtration in step C) and the addition of the solvent or the solvent mixture are carried out in a clean-room environment.
13. The process as claimed in claim 1 , wherein the solution obtained in step C) is packaged in containers suitable for clean-room conditions.
14. The process as claimed in claim 13 , characterized in that the packaged solution is blanketed with an inert atmosphere.
15. The process as claimed in claim 1 , wherein the after-treatment in step B) reduces the molecular weight of the polymeric organic semiconductor.
16. The process as claimed in claim 1 , wherein a deep bed filter and/or membrane filter is used in step C).
17. A solution of polymeric semiconductors which is prepared as claimed in claim 1 .
18. A polymeric organic light-emitting diode (PLED), organic integrated circuit (O-IC), organic field effect transistor (OFET), organic thin film transistor (OTFT), organic solar cell (O-SC) or organic laser diode (O-laser) produced using a solution as claimed in claim 17 .
19. The process as claimed in claim 4 , wherein the polymeric organic semiconductor is dissolved in the solvent (step A) by stirring or mixing, and optionally with heating.
20. The process as claimed in claim 1 , wherein all steps A), step B) and step C) are carried out under an inert atmosphere.
21. The process as claimed in claim 11 , wherein the filtration in step C) and the addition of the solvent or the solvent mixture are carried out in a clean-room environment of class 100.
22. The process as claimed in claim 11 , wherein the filtration in step C) and the addition of the solvent or the solvent mixture are carried out in a clean-room environment of class 10.
23. A process for producing layers of polymeric semiconductors which comprises using the solution as claimed in claim 17 .
24. The process as claimed in claim 23 , wherein the process is a coating process.
25. The process as claimed in claim 24 , wherein the coating processes is a doctor blade coating, spin coating, meniscus coating, transfer printing, ink jet printing, offset printing or screen printing process.