Method for producing a pedot film

Abstract

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.

1 . A method for producing a poly (3,4-ethylenedioxythiophene) (PEDOT) film comprising a substrate and at least one PEDOT layer on at least one surface of the substrate
 wherein the method comprises the steps of:
 a) applying a solution comprising an oxidant and a base inhibitor on at least one surface of the substrate so as to form an oxidant coating on at least one surface of the substrate, 
 b) subjecting the oxidant-coated substrate formed in step a) to a polymerization step by exposing the surface(s) of the oxidant-coated substrate to 3,4-ethylenedioxythiophene (EDOT) monomer vapour at a polymerization temperature to form a PEDOT layer on the surface(s) of the oxidant-coated substrate, 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.   
     
     
         2 . The method of  claim 1 , wherein the substrate is a non-conducting substrate. 
     
     
         3 . The method of  claim 1 , wherein the method comprises the steps of:
 c) applying the solution comprising the oxidant and the base inhibitor on at least one surface of the PEDOT layer formed in step b) so as to form an oxidant coating on the at least one surface of the PEDOT layer,   d) subjecting the oxidant-coated PEDOT layer formed in step c) to a polymerization step by exposing the surface(s) of the oxidant-coated PEDOT layer to 3,4-ethylenedioxythiophene (EDOT) monomer vapour at a polymerization temperature to form a subsequent PEDOT layer on the surface(s) of the oxidant-coated PEDOT layer,   wherein, during the polymerization step, the temperature of the oxidant-coated PEDOT film is kept at a controlled substrate temperature and wherein the controlled substrate temperature is 2-40° C. lower than the polymerization temperature.   
     
     
         4 . The method of  claim 3 , wherein the method comprises repeating step c) and step d) at least once. 
     
     
         5 . The method of  claim 1 , wherein the temperature of the oxidant-coated substrate is kept at a controlled substrate temperature during the polymerization step, and the controlled substrate temperature is 2-30° C., or 3-20° C., or 3-15° C., or 5-15° C., or 8-12° C. lower than the polymerization temperature. 
     
     
         6 . The method of  claim 1 , wherein the method is vapour phase polymerization (VPP). 
     
     
         7 . The method of  claim 1 , wherein the polymerization temperature is 55-95° C. and the controlled substrate temperature is 40-70° C., or 60-85° C. and the controlled substrate temperature is 45-70° C., or the polymerization temperature is 65-80° C. and the controlled substrate temperature is 55-70° C., or the polymerization temperature is 67-77° C. and the controlled substrate temperature is 56-66° C., or the polymerization temperature is 72-77° C. and the controlled substrate temperature is 61-66° C. 
     
     
         8 . The method of  claim 1 , wherein the temperature of the oxidant-coated substrate and/or the oxidant-coated PEDOT film is kept at the controlled substrate temperature substantially during the entire polymerization step. 
     
     
         9 . The method of  claim 1 , wherein the polymerization step comprises two sequential processing periods, the temperature of the oxidant-coated substrate and/or the oxidant-coated PEDOT film is kept at the controlled substrate temperature throughout one of the processing periods. 
     
     
         10 . The method of  claim 1 , wherein the polymerization step comprises three sequential processing periods, wherein the temperature of the oxidant-coated substrate and/or the oxidant-coated PEDOT film is kept at the controlled substrate temperature throughout the middle processing period. 
     
     
         11 . The method of  claim 1 , wherein the method comprises the step of cleaning the substrate before step a). 
     
     
         12 . The method of  claim 1 , wherein the solution comprising the oxidant and the base inhibitor is spin-coated on at least one surface of the substrate in step a) and/or on at least one surface of the PEDOT layer formed in step c). 
     
     
         13 . The method of any of  claim 1 , wherein the method comprises cleaning, drying and/or heating the oxidant-coated substrate before step b), and/or the PEDOT polymer film from step c) before step d). 
     
     
         14 . The method of  claim 1 , wherein the method comprises the step of annealing the PEDOT film at a temperature of 50-100° C. after polymerization and optionally washing and drying the annealed PEDOT film. 
     
     
         15 . The method of any of  claim 2 , wherein the method comprises the step of cleaning the PEDOT polymer film received from step b) before step c). 
     
     
         16 . The method of  claim 1 , wherein the duration of the polymerization step is 1-20 minutes, or 1-10 minutes, or 2-8 minutes. 
     
     
         17 . The method of  claim 1 , wherein the duration of the polymerization step processing period wherein the temperature of the oxidant-coated substrate and/or the oxidant-coated PEDOT film is kept at a controlled substrate temperature is 20-80%, or 30-60%, or 35-40% of the duration of the polymerization step. 
     
     
         18 . The method of  claim 1 , wherein the non-conductive substrate is glass or polyethylene terephthalate (PET). 
     
     
         19 . The method of  claim 1 , wherein the oxidant is Iron(III) p-toluenesulfonate hexahydrate (FETOS). 
     
     
         20 . The method of  claim 1 , wherein the base inhibitor is pyridine. 
     
     
         21 . A conducting PEDOT film, comprising:
 a non-conductive substrate,   a PEDOT layer having anions from an oxidant/oxidants embedded in the PEDOT layer on the non-conductive substrate,   wherein the conducting PEDOT film has a conductivity of over 2100 S/cm and a sheet resistance of below 200 Ω/□.   
     
     
         22 . A conducting PEDOT film obtainable by the method defined in  claim 2  comprising:
 a non-conductive substrate, 
 a PEDOT layer having anions from an oxidant/oxidants embedded in the PEDOT layer on the non-conductive substrate, 
 wherein the conducting PEDOT film has a conductivity of over 2100 S/cm and a sheet resistance of below 200 Ω/□. 
 
     
     
         23 . The conducting PEDOT film of  claim 21  comprising 1-20, or 1-15 PEDOT layers on the non-conductive substrate. 
     
     
         24 . The conducting PEDOT film of  claim 21 , wherein the roughness average of the conducting PEDOT film is below 3.5 nm. 
     
     
         25 . The conducting PEDOT film of  claim 21 , wherein the % transmittance of the conducting PEDOT film is over 30% T. 
     
     
         26 . The conducting PEDOT film of  claim 21 , wherein the non-conductive substrate is glass or polyethylene terephthalate (PET). 
     
     
         27 . The conducting PEDOT film of  claim 21 , wherein the PEDOT layer has anions from Iron(III) p-toluenesulfonate hexahydrate (FETOS) embedded in the PEDOT layer on the non-conductive substrate. 
     
     
         28 . The conducting PEDOT film of  claim 21 , wherein the thickness of the film is 10-500 nm or 10 -200 nm. 
     
     
         29 . An electronic device, characterized in that the device comprises a conducting PEDOT film as defined in  claim 21 . 
     
     
         30 . An electronic device of  claim 29 , wherein the device is a display, a flat panel display, an optoelectronic devise such as an organic light emitting diode OLED, an organic solar cell, a dye-sensitized solar cell, a perovskite solar cell, a smart window, a fuel cell, an organic electrochemical transistor. an electrochemical transducer, an electrochromic device, an electroluminescent device, an electroluminescent display, an organic capacitor, a supercapacitor, a sensor, a biosensor, an energy harvesting device, an antistatic material, a photovoltaic device, a storage device or a thermoelectric device. 
     
     
         31 . Use of the conducting PEDOT film as defined in  claim 21  as an antistatic coating or an electrode in/of an electronic device