1. A method of producing an optoelectronic device comprising: A) providing a substrate, B) applying a first electrode to the substrate, C) applying a first organic layer stack to the first electrode, D) producing a charge-generating layer stack on the first organic layer stack, E) applying a second organic layer stack to the charge-generating layer stack, F) applying a second electrode to the second organic layer stack, wherein step D) comprises: D1) applying a solution of a first metal oxide precursor to the first organic layer stack, wherein the solution of the first metal oxide precursor and the first organic layer have the same temperature between 30° C. to 60° C. and the solution of the first metal oxide precursor and the first organic layer stack are heated, prior to step D1) to the same temperature of 30° C. to 60° C., D2) generating a first charge-generating layer comprising a first metal oxide, D3) applying a solution of a second metal oxide precursor to the first charge-generating layer, wherein the solution of the second metal oxide precursor and the first charge-generating layer have a temperature of 30° C. to 60° C. and the solution of the second metal oxide precursor and the first charge-generating layer are heated, prior to step D3), to the same temperature of 30° C. to 60° C., D4) generating a second charge-generating layer comprising a second metal oxide.