Pedot in perovskite solar cells

A dispersion comprising:

• a) a salt or a complex of a cationic polythiophene with a counter-ion;
• b) an organic solvent with a ΔA-value of less than 5%, wherein the ΔA-value is calculated by formula (I)
• ΔA=(A0−AD)/A0×100% (I)
• wherein A0 is the absorption before and AD the absorption after a CH3NH3PbI3-layer has been superimposed with the organic solvent b) for 30 s, in each case determined at 490 nm.

A process for the preparation of a photovoltaic device, comprising the process steps:

• i) providing a multilayer-precursor body comprising
• a first electrode;
• a photoactive layer, wherein the photoactive layer is made of a material having a perovskite type crystal structure;
• and
• an electron transport layer that is localized between the first electrode and the photoactive layer;
• ii) partially superimposing the photoactive layer of the multilayer-precursor body with a coating composition A) comprising an electrically conductive polymer and b) an organic solvent;
• iii) partially removing the organic solvent b) from the coating composition A) superimposed in process step ii), thereby obtaining an electrically conductive hole transport layer superimposed on the photoactive layer;
• and
• iv) partially superimposing the hole transport layer with a second electrode.