A method for producing a PEDOT film on a substrate comprising a substrate and at least one PEDOT layer on a surface of the substrate is disclosed. The method comprises applying a solution comprising an oxidant and a base inhibitor on a surface of the substrate; subjecting the oxidant-coated substrate to a polymerization step by exposing the surface(s) of the oxidant-coated substrate to EDOT monomer vapour at a polymerization temperature; and wherein, during the polymerization step, the temperature of the oxidant-coated substrate is kept at a controlled substrate temperature and wherein the controlled substrate temperature is 2-40° C. lower than the polymerization temperature. Further is disclosed a conducting PEDOT film, an electronic device comprising the conducting PEDOT film and different uses of the conducting PEDOT film. Further, is disclosed a method for producing a polymer film formed of a copolymer, a conducting polymer film, an electronic device comprising the conducting polymer film and different uses of the conducting polymer film.