PEDOT in perovskite solar cells
The present invention relates to a process for the production of a layered body (1), at least comprising the process steps: I) provision of a photoactive layer comprising a material having a perovskite type crystal structure; II) superimposing the photoactive layer at least partially with a coating composition A) comprising an electrically conductive polymer a) and an organic solvent b); III) at least partial removal of the organic solvent b) from the coating composition A) superimposed in process step II), thereby obtaining an electrically conductive layer superimposed on the photoactive layer. The present invention also relates to a layered body obtainable by this process, to dispersions, to an electronic device, to a process for the preparation of a photovoltaic device and to the photovoltaic device that is obtainable by this process.
1. A dispersion comprising:
a) a salt of a cationic polythiophene with a counter-ion or a complex of a cationic polythiophene with a counter-ion;
b) an organic solvent with a dielectric constant between 1×10 −30 and 20×10 −30 Cm;
c) an additive selected from one of a metal nanowire, a carbon nanotube, a graphene and a crosslinking agent.
2. The dispersion according to claim 1 , wherein the organic solvent b) has a ΔA-value of less than 5%, wherein AA is calculated by formula (I)
Δ A =(Δ 0 −ΔA D )/ A 0 ×100% (I)
in which A 0 is the absorption before and A D the absorption after a CH 3 NH 3 PbI 3 -layer has been superimposed with the solvent for 30 s, in each case determined at 490 nm.
3. The dispersion according to claim 2 , wherein the organic solvent b) has a ΔA-value of less than 2.5%.
4. The dispersion according to claim 3 , wherein the organic solvent b) has a ΔA-value of less than 1%.
5. The dispersion according to claim 1 , wherein the polymeric counter ion is a copolymer comprising polymerized styrene monomer units at least a part of which is sulfonated and polymerized non-sulfonated monomer units and wherein molar ratio of the non-sulfonated monomer units is at least 5%, based on the total amount of monomer units in the copolymer.
6. The dispersion according to claim 1 , wherein the counter-ion is a hydrogenated styrene-isoprene block copolymers with the structure A-B-C-B-A, in which the block A corresponds to a polystyrene block which is at least partially substituted with tert-butyl groups, the block B corresponds to a block of alternating copolymerised ethylen-propylene units and the block C corresponds to a sulphonated polystyrene block.
7. The dispersion according to claim 1 , wherein the conductivity of an electrically conductive layer made by coating a glass substrate with the dispersion and drying the thus obtained layer structure for 3 minutes at 200° C. on a hot plate is at least 0.2 S/cm.
8. The dispersion according to claim 7 , wherein the conductivity is at least 1 S/cm.
9. The dispersion according to claim 1 , wherein the water content of the dispersion is less than 2 wt.-%.
10. The dispersion according to claim 9 , wherein the water content of the dispersion is less than 0.5 wt.-%.
11. A dispersion comprising:
a) a salt of a cationic polythiophene with a counter-ion or a complex of a cationic polythiophene with a counter-ion; and
b) an organic solvent;
wherein the dispersion has an iron content of less than 100 ppm, based on the total weight of the dispersion.
12. The dispersion according to claim 11 , wherein the dispersion has an iron content of less than 50 ppm, based in the total weight of the dispersion.
13. The dispersion according to claim 12 , wherein the dispersion has an iron content of less than 10 ppm, based in the total weight of the dispersion.
14. The dispersion according to claim 11 , wherein the organic solvent b) has a dielectric constant between 1×10 −30 and 20×10 −30 Cm.
15. The dispersion according to claim 14 , wherein the organic solvent b) has a dielectric constant between 1×10 −30 and 17×10 −30 Cm.
16. The dispersion according to claim 15 , wherein the organic solvent b) has a dielectric constant between 1×10 −30 and 7×10 −30 Cm.