Method for manufacturing PEDOT film

Abstract

A method for producing a PEDOT film on a substrate is disclosed, the method comprising: applying a solution containing an oxidizing agent and a base inhibitor onto the surface of the substrate to form an oxidizing agent coating on at least one surface of the substrate; and subjecting the oxidizing agent-coated substrate to a polymerization step by exposing the surface of the oxidizing agent-coated substrate to PEDOT monomer vapor at a polymerization temperature, wherein the temperature of the oxidizing agent-coated substrate is maintained at a controlled substrate temperature, the controlled substrate temperature being 2 to 40° C. lower than the polymerization temperature. Additionally, a conductive PEDOT film, an electronic device including the conductive PEDOT film, and different uses of the conductive PEDOT film are disclosed. [Selection diagram] None

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a poly(3,4-ethylenedioxythiophene) (PEDOT) film. The present disclosure further relates to a conductive PEDOT film. The present disclosure further relates to an electronic device including the conductive PEDOT film and the use of the conductive PEDOT film as an antistatic coating or an electrode in the electronic device.

Background Art

[0002] Conductive PEDOT films are used in different fields such as antistatic coatings, perovskite solar cells, organic solar cells, dye-sensitized solar cells, electrochemical transducers, electrochromic devices, electroluminescent devices, thermoelectric devices, smart windows, OLEDs, optoelectronics, and supercapacitors. Conductive PEDOT films can be manufactured, for example, by electrochemical polymerization of PEDOT on a conductive substrate, oxidative chemical vapor deposition (oCVD), or vacuum vapor polymerization (VVPP) techniques. When forming a conductive PEDOT film for an electronic device, its conductivity, low sheet resistance, morphology (average roughness), and light transmittance are important.

Summary of the Invention

[0003] A method for manufacturing a poly(3,4-ethylenedioxythiophene) (PEDOT) film on a substrate is disclosed, which includes a substrate and at least one PEDOT layer on at least one surface of the substrate. The method includes applying a solution containing an oxidizing agent and a base inhibitor on at least one surface of the substrate to form an oxidizing agent coating on at least one surface of the substrate, and subjecting the formed oxidizing agent-coated substrate to a polymerization step by exposing the surface of the oxidizing agent-coated substrate to 3,4-ethylenedioxythiophene (EDOT) monomer vapor at a polymerization temperature, thereby forming a PEDOT layer on the surface of the oxidizing agent-coated substrate. During the polymerization step, the temperature of the oxidizing agent-coated substrate is maintained at a controlled substrate temperature, and the controlled substrate temperature is 2 to 40 °C lower than the polymerization temperature.

[0004] Furthermore, a conductive PEDOT film is disclosed. The conductive PEDOT film can include a non-conductive substrate and a PEDOT layer having anions from one or more oxidizing agents embedded in the PEDOT layer on the non-conductive substrate, and the conductive PEDOT film has a conductivity of more than 2100 S / cm and a sheet resistance of less than 200 Ω / □.

[0005] Furthermore, a conductive PEDOT film obtainable by a method for manufacturing a PEDOT film including a non-conductive substrate and at least one PEDOT layer on at least one surface of the non-conductive substrate as disclosed in the present disclosure is disclosed.

[0006] Furthermore, an electronic device is disclosed. The electronic device may include a conductive PEDOT film as disclosed in the present disclosure.

[0007] Furthermore, the use of a conductive PEDOT film is disclosed.

[0008] The accompanying drawings are included to provide a further understanding of the embodiments, constitute a part of this specification, and illustrate various embodiments.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0010] This application relates to a method for manufacturing a poly(3,4-ethylenedioxythiophene) (PEDOT) film comprising a substrate and at least one PEDOT layer on at least one surface of the substrate, the method comprising: a) applying a solution containing an oxidizing agent and a base inhibitor on at least one surface of the substrate to form an oxidizing agent coating on at least one surface of the substrate; b) The oxidant-coated substrate formed in step a) undergoes a polymerization step by exposing the surface of the oxidant-coated substrate to 3,4-ethylenedioxythiophene (EDOT) monomer vapor at a polymerization temperature, thereby forming a PEDOT layer on the surface of the oxidant-coated substrate; comprising During the polymerization step, the temperature of the oxidant-coated substrate is maintained at a controlled substrate temperature, and the controlled substrate temperature is 2 to 40 °C lower than the polymerization temperature.

[0011] The expression that the PEDOT layer is "on" the surface of the substrate in the PEDOT film should be understood in this specification, unless otherwise specified, to mean that the PEDOT layer is polymerized, formed lying on the substrate, or at least partially embedded therein. The substrate can act as a carrier or support structure for the PEDOT layer. The substrate can be changed, and the material of the substrate can be changed according to the application for which the PEDOT film is used.

[0012] The expression "film" should be understood in this specification, unless otherwise specified, to refer to a structure having a lateral dimension that is substantially larger than its thickness. In that sense, a film can be considered a "thin" structure.

[0013] The polymerization temperature is the temperature of the monomer vapor during the polymerization step.

[0014] In one embodiment, the substrate is a non-conductive substrate. The expression that the substrate is "non-conductive" should be understood in this specification, unless otherwise specified, to mean that the substrate has a sheet resistance of 10 MΩ / sq or more.

[0015] The non-conductive substrate may be a substrate such as glass, polymer, paper, cellulose, fabric, cloth, wood, leather, cotton, pottery, composite materials such as cellulose-wood composite materials, glass fiber, Teflon (registered trademark), rubber, quartz, paint, carbon materials and / or non-conductive minerals. The non-conductive polymer substrate may be selected from the group consisting of plastic materials selected from the group consisting of polyester, polyethylene terephthalate (PET), polycarbonate (PC), polyamide (PI), polyester sulfone (PES), polystyrene resin (PS), and amorphous polyester (A-PET or PET-G), and mixtures thereof. The non-conductive substrate may be a flexible non-conductive substrate. The flexible substrate can be used in the production of flexible PEDOT films that can be bent and folded.

[0016] The oxidizing agent is a substance that induces the polymerization of monomers and can act as a dopant after the polymerization of the conductive polymer. The embedded anions can remain within the PEDOT structure to act as dopant ions. The conductivity of the PEDOT polymer can be due to the delocalization of electrons or holes during oxidation (doping). The oxidizing agent can be selected from the group consisting of iron(III) p-toluenesulfonate, iron(III) chloride, p-toluenesulfonic acid, iodine, bromine, molybdophosphoric acid, ammonium persulfate, DL-tartaric acid, polyacrylic acid, copper chloride, ferric chloride, naphthalenesulfonic acid, camphorsulfonic acid, iron(III) toluenesulfonate, iron(III) perchlorate, Cu(ClO4)2·6H2O, ammonium cerium(IV) nitrate, cerium(IV) sulfate, and mixtures thereof.

[0017] The base inhibitor reduces the activity of the oxidizing agent and the polymerization rate. This may change the conductivity of the deposited polymer. The base inhibitor can be selected from the group consisting of amine-based compounds and nitrogen atom-containing saturated or unsaturated heterocyclic compounds, such as pyridine-based, imidazole-based, or pyrrole-based compounds, water vapor, glycerol, and glycol derivatives, and mixtures thereof.

[0018] The oxidizing agent solution of the present invention contains an oxidizing agent, a base inhibitor, and a solvent. The solvent can be selected from the group consisting of organic solvents such as n-butanol methyl alcohol, 2-butyl alcohol, ethyl cellosolve, ethyl alcohol, cyclohexane, ethyl acetate, toluene, acetonitrile, and methyl ethyl ketone, and mixtures thereof.

[0019] In one embodiment, the PEDOT layer is doped.

[0020] In one embodiment, this method is carried out by gas-phase polymerization.

[0021] Gas-phase polymerization is a polymerization technique in which only the monomer is converted into the gas phase. The VPP method can include the steps of coating a substrate with a solution of an oxidizing agent and a base inhibitor, and then drying to remove traces of the solvent.

[0022] In one embodiment, the gas-phase polymerization is carried out under atmospheric pressure. Gas-phase polymerization carried out under atmospheric pressure is easy to control. Neither pressure control nor sophisticated devices or vacuum furnaces are required. This method can also be used for the production of large-area films.

[0023] The polymerization temperature affects the properties of the resulting PEDOT film, such as the polymerization rate, by controlling the evaporation rate of the monomer and / or the mobility of the polymer chains. When the temperature decreases, the concentration of vapor molecules increases. The substrate temperature and the polymerization temperature control the polymerization rate. The polymerization temperature and the substrate temperature affect the properties of the formed PEDOT film, such as conductivity, transparency, sheet resistance, and morphology. The controlled substrate temperature is a factor in controlling the polymerization rate that controls the morphology of the PEDOT film. The controlled substrate temperature provides a uniform and homogeneous property to the PEDOT film.

[0024] In one embodiment, a solution containing an oxidizing agent and a base inhibitor is applied to one surface of a substrate, and the oxidant-coated surface of the substrate is exposed to 3,4-ethylenedioxythiophene (EDOT) monomer vapor at a polymerization temperature to form one PEDOT layer on the surface of the oxidant-coated substrate, thus producing a single-layer PEDOT film.

[0025] The method for manufacturing a multilayer PEDOT film can be carried out by gas-phase polymerization for each layer. The PEDOT film can be formed by depositing PEDOT layers with a washing step sandwiched in between.

[0026] In one embodiment, the above method is c) applying the solution containing the oxidizing agent and the base inhibitor onto at least one surface of the PEDOT layer formed in step b) 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 of the oxidant-coated PEDOT layer to 3,4-ethylenedioxythiophene (EDOT) monomer vapor at a polymerization temperature to form a subsequent PEDOT layer on the surface of the oxidant-coated PEDOT layer; including During the polymerization step, the temperature of the oxidant-coated PEDOT film is maintained at a controlled substrate temperature, and the controlled substrate temperature is 2 to 40 °C lower than the polymerization temperature.

[0027] In one embodiment, the temperature of the oxidant-coated substrate is maintained at a controlled substrate temperature during the polymerization step, and the controlled substrate temperature is 2 to 30 °C lower than the polymerization temperature.

[0028] In one embodiment, the temperature of the oxidant-coated substrate is maintained at a controlled substrate temperature during the polymerization step, and the controlled substrate temperature is 3 to 20 °C lower than the polymerization temperature.

[0029] In one embodiment, the temperature of the oxidant-coated substrate is maintained at a controlled substrate temperature during the polymerization step, and the controlled substrate temperature is 3 to 15 °C lower than the polymerization temperature.

[0030] In one embodiment, the temperature of the oxidant-coated substrate is maintained at a controlled substrate temperature during the polymerization step, and the controlled substrate temperature is 5 to 15 °C lower than the polymerization temperature.

[0031] In one embodiment, the temperature of the oxidant-coated substrate is maintained at a controlled substrate temperature during the polymerization step, and the controlled substrate temperature is 8 to 12 °C lower than the polymerization temperature.

[0032] In one embodiment, a solution containing an oxidant and a base inhibitor is applied onto the surface of one PEDOT layer formed in step b), i.e., one layer of PEDOT film, and the oxidant-coated surface of the PEDOT layer is exposed to EDOT monomer vapor at the polymerization temperature to form a second PEDOT layer on the surface of the oxidant-coated PEDOT layer, thus producing a two-layer PEDOT film.

[0033] In one embodiment, the method includes repeating steps c) and d) at least once to produce a multilayer PEDOT film.

[0034] During the polymerization step, the substrate temperature and the polymerization temperature are controlled separately. In one embodiment, the polymerization temperature is 55 to 95 °C and the controlled substrate temperature is 40 to 70 °C. In one embodiment, the polymerization temperature is 60 to 85 °C and the controlled substrate temperature is 45 to 70 °C. In one embodiment, the polymerization temperature is 65 to 80 °C and the controlled substrate temperature is 55 to 70 °C, or the polymerization temperature is 67 to 77 °C and the controlled substrate temperature is 56 to 66 °C, or the polymerization temperature is 72 to 77 °C and the controlled substrate temperature is 61 to 66 °C. High temperatures are not required in the gas-phase polymerization of the present invention.

[0035] In one embodiment, the temperature of the oxidant-coated substrate and / or the oxidant-coated PEDOT film is maintained at a controlled substrate temperature substantially throughout the polymerization step.

[0036] In one embodiment, the polymerization step is subdivided into successive treatment periods in order to adjust the polymerization rate.

[0037] In one embodiment, the polymerization step includes two successive treatment periods, and the temperature of the oxidant-coated substrate and / or the oxidant-coated PEDOT film is maintained at a controlled substrate temperature throughout one of the treatment periods.

[0038] In one embodiment, the polymerization step includes three successive treatment periods, and the temperature of the oxidant-coated substrate and / or the oxidant-coated PEDOT film is maintained at a controlled substrate temperature throughout the middle treatment period.

[0039] During a treatment period in which the substrate is not maintained at a controlled substrate temperature, the substrate temperature can change towards the ambient temperature, i.e., the polymerization temperature. If the substrate temperature is higher than the polymerization temperature, the substrate temperature is cooled towards the polymerization temperature, or if the substrate temperature is lower than the polymerization temperature at the start of such a treatment period, the substrate temperature is heated towards the polymerization temperature.

[0040] In one embodiment, the method of the present application includes a step of cleaning the substrate before step a). In one embodiment, the substrate is cleaned by ultrasonic treatment with a solvent. The solvent can be selected from the group consisting of organic solvents such as acetone and EtOH, water, and mixtures thereof. The cleaning step may be repeated using the same or different solvents.

[0041] In one embodiment, the cleaned substrate is immersed in a hot solution of H2O:NH4OH (25%):H2O2 (30%) with a volume ratio of 5:1:1 to remove organic impurities remaining on the surface, followed by oxygen plasma treatment.

[0042] In one embodiment, the oxidant solution is spin-coated onto at least one surface of the substrate in step a). In one embodiment, the oxidant solution is spin-coated onto at least one surface of at least one surface of the PEDOT layer formed in step c). In one embodiment, the oxidant solution is spin-coated onto the substrate at 800 - 3500 rpm. In one embodiment, the oxidant solution is spin-coated onto the substrate over 5 - 30 seconds.

[0043] In one embodiment, the method includes, prior to step b), the steps of washing, drying, and / or heating the oxidant-coated non-conductive substrate from step a). In one embodiment, the method includes, prior to step d), the steps of washing, drying, and / or heating the PEDOT film from step c). In one embodiment, the oxidant-coated non-conductive substrate is heated at 80 - 100 °C. In one embodiment, the PEDOT film from step c) is heated at 80 - 100 °C.

[0044] In one embodiment, the method includes the step of annealing the PEDOT film at a temperature of 50 - 100 °C after polymerization. The PEDOT film can be annealed to avoid stress rupture of the film during the washing step. Since traces of unconsumed oxidant and monomer can reduce conductivity, the annealed PEDOT film can be washed to remove unreacted oxidant, monomer, and any other impurities. In one embodiment, the annealed PEDOT film is completely immersion-rinsed in ethanol and subsequently washed with MeCN. In one embodiment, the annealed PEDOT film is dried. In one embodiment, the annealed PEDOT film is dried under a dry nitrogen gas stream.

[0045] In one embodiment, this method includes, before step c), a step of washing the PEDOT polymer film received from step b). In one embodiment, the PEDOT polymer film is washed by annealing the PEDOT film at a temperature of 50 to 100 °C after polymerization. In one embodiment, the annealed PEDOT film is completely immersed and rinsed in ethanol and then washed with MeCN. In one embodiment, the annealed PEDOT film is dried. In one embodiment, the annealed PEDOT film is dried under a flowing dry nitrogen gas.

[0046] The polymerization time may affect properties such as the sheet resistance and roughness average of the formed PEDOT film.

[0047] In one embodiment, the duration of the polymerization step is 1 to 20 minutes. In one embodiment, the duration of the polymerization step is 1 to 10 minutes. In one embodiment, the duration of the polymerization step is 2 to 8 minutes. The polymerization step is fast.

[0048] In one embodiment, the duration of the processing period of the polymerization step, during which the temperature of the non-conductive substrate coated with the oxidizing agent and / or the PEDOT film coated with the oxidizing agent is maintained at a controlled substrate temperature, is 20 to 80% of the duration of the polymerization step.

[0049] In one embodiment, the duration of the processing period of the polymerization step, during which the temperature of the non-conductive substrate coated with the oxidizing agent and / or the PEDOT film coated with the oxidizing agent is maintained at a controlled substrate temperature, is 30 to 60% of the duration of the polymerization step. In one embodiment, the duration of the processing period of the polymerization step, during which the temperature of the non-conductive substrate coated with the oxidizing agent and / or the PEDOT film coated with the oxidizing agent is maintained at a controlled substrate temperature, is 35 to 40% of the duration of the polymerization step.

[0050] In one embodiment, the non-conductive substrate is glass. In one embodiment, the non-conductive substrate is polyethylene terephthalate (PET).

[0051] In one embodiment, the oxidizing agent is iron(III) p-toluenesulfonate hexahydrate (FETOS).

[0052] In one embodiment, the base inhibitor is pyridine.

[0053] In one embodiment, the oxidizing agent solution contains or consists of FETOS and pyridine in n-butanol. In one embodiment, the oxidizing agent solution contains the oxidizing agent at a ratio of 5 wt% to 50 wt% based on the volume of the oxidizing agent solution.

[0054] The present application further relates to a conductive PEDOT film, which comprises a non-conductive substrate and a PEDOT layer having anions from one or more oxidizing agents embedded in the PEDOT layer on the non-conductive substrate, and the conductive PEDOT film has a conductivity of more than 2100 S / cm and a sheet resistance of less than 200 Ω / □.

[0055] The present application further relates to a conductive PEDOT film obtainable by the method of the present application, the conductive PEDOT film comprises a non-conductive substrate and a conductive PEDOT layer having anions from one or more oxidizing agents embedded in the PEDOT layer on the non-conductive substrate, and the conductive PEDOT film has a conductivity of more than 2100 S / cm and a sheet resistance of less than 200 Ω / □.

[0056] In one embodiment, the conductive PEDOT film has a conductivity of more than 3200 S / cm and a sheet resistance of less than 21 Ω / □. In one embodiment, the conductive PEDOT film has a conductivity of more than 3200 S / cm and a sheet resistance of 12 Ω / □.

[0057] The sheet resistance (r sheet ) of the PEDOT film can be calculated using the Van der Pauw method. The resistivity (r) of the film is obtained by multiplying the sheet resistance by the film thickness (d) according to the following formula (1): r = rsheet d (1)

[0058] The conductivity (s) of the film is obtained according to the following formula (2): s = 1 / r (2)

[0059] CV and EIS techniques can be used to evaluate electrochemical properties. The charge (Q) is calculated by integrating the cyclic voltammogram in the potential range of -0.25 to 0.75 V with Origin software. This is further processed using the following formula to obtain the capacitance value. Areal capacitance: C A = Q / (ΔV * A) (3) Volumetric capacitance: C V = Q / (ΔV * V) (4) Here, "ΔV" is the potential window, "A" is the area, and "V" is the volume of the working electrode.

[0060] In one embodiment, the conductive PEDOT film includes 1 to 20 PEDOT layers on a non-conductive substrate. In one embodiment, the conductive PEDOT film includes 1 to 15 PEDOT layers on a non-conductive substrate. In one embodiment, the conductive PEDOT film includes 1 to 10 PEDOT layers on a non-conductive substrate.

[0061] In one embodiment, the average roughness of the conductive PEDOT film is less than 3.5 nm.

[0062] The average roughness value of the PEDOT film is obtained from the AFM image using WSXM software. The average roughness (R a ) is the average (absolute value) of the difference between the average height of the sample and the height of each individual point. This number varies depending on the range of the interval. It indicates how uniform or rough the PEDOT film is.

[0063] In one embodiment, the % transmittance of the conductive PEDOT film at 550 nm is greater than 30%T. In one embodiment, the % transmittance of the conductive PEDOT film is greater than 80%T.

[0064] The UV-Vis spectrum can be recorded using an Agilent 8453 spectrophotometer. The % transmittance (%T) is calculated from the absorbance data using the following equation (5). (%T)=(10^(Abs))*100 (5)

[0065] In one embodiment, the non-conductive substrate of the PEDOT film is glass. In one embodiment, the non-conductive substrate of the PEDOT film is polyethylene terephthalate (PET).

[0066] In one embodiment, the PEDOT layer has anions from iron(III) p-toluenesulfonate hexahydrate (FETOS) embedded in the PEDOT layer on the non-conductive substrate.

[0067] The thickness of the conductive PEDOT film can be designed according to the properties of the conductive PEDOT film, particularly conductivity, resistance, average roughness or transmittance, or a combination of these properties. In one embodiment, the thickness of the PEDOT film is 10 to 500 nm, or 10 to 300 nm, or 20 to 200 nm.

[0068] This application further relates to an electronic device comprising the conductive PEDOT film of this application.

[0069] In one embodiment, the electronic device is a display, a flat panel display, an optoelectronic device 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. In one embodiment, the electronic device is an optoelectronic device. In one embodiment, the electronic device is a transparent electrode. In one embodiment, the electronic device is a supercapacitor.

[0070] This application further relates to the use of the conductive PEDOT film of this application as an antistatic coating or electrode within / on an electronic device.

[0071] The method of this application has the additional utility of being simple, low cost, and rapid for atmospheric pressure controlled polymerization. Further, the method of this application has the additional utility of producing thin multilayer PEDOT films on the nanometer scale. Further, this method can be used on a large surface area and is not limited to conductive substrates. The PEDOT film of this application has the additional utility of being very uniform and homogeneous, smooth and flexible. Further, the PEDOT film of this application has the additional utility of having high conductivity and transmittance.

Examples

[0072] Next, various embodiments will be referred to in detail, and an example thereof is shown in the accompanying drawings.

[0073] The following description discloses several detailed embodiments so that those skilled in the art can utilize the embodiments based on the present disclosure. Not all steps or features of the embodiments are discussed in detail, and many of the steps or features will be apparent to those skilled in the art based on this specification.

[0074] For the sake of brevity, in the following exemplary embodiments, when components are repeated, the item numbers are maintained.

[0075] FIG. 1 shows a gas-phase polymerization cell for carrying out gas-phase polymerization. The polymerization cell 1 has a stand 3 for a substrate 4 and a metal block 5. A thermostatic bath 7 is attached to the polymerization cell 1 to keep the temperature of the monomer vapor 6 at the polymerization temperature. A thermostatic bath 8 is attached to the metal block 5 to keep the temperature of the substrate 4 at a controlled substrate temperature. The polymerization cell 1 includes a lid 2 used to close the polymerization cell 1.

[0076] (Example 1: Preparation of PEDOT Film) A glass slide (substrate) (37.5 mm × 25 mm) was ultrasonically treated and washed with acetone, water, and EtOH for 5 minutes each. The washed substrate was immersed in a hot solution (80 °C) of H2O:NH4OH (25%):H2O2 (30%) with a volume ratio of 5:1:1 for 5 minutes to remove organic impurities remaining on the surface, and then subjected to oxygen plasma treatment for 5 minutes. 60 μL of the oxidizing agent solution was spin-coated onto the substrate at 1450 rpm for 20 seconds. The oxidizing agent-coated substrate was dried on a hot plate at 90 °C for 90 seconds. The dried substrate was transferred to Cell 1 containing EDOT monomer 6 preheated at 75 °C such that the coated surface faced the vapor. Polymerization was carried out in three different steps over 4 minutes. For the first 90 seconds, Cell 1 was covered with a glass lid 2. Then, the cover of Cell 1 was removed, and for the next 90 seconds, the substrate temperature was maintained at 65 °C by a heated metal block 5. The metal block 5 was removed, and Cell 1 was covered with a glass lid 2 for 60 seconds. Annealing of the film was carried out after polymerization on a hot plate at 90 °C for 90 seconds. After annealing, the film was cooled to room temperature, rinsed thoroughly in ethanol and then in MeCN to remove unreacted oxidizing agent, monomer, and any other impurities. Washing was performed to remove traces of unconsumed oxidizing agent and monomer. Failure to wash may reduce conductivity. After washing, the film was dried under a stream of dry nitrogen gas. This procedure was repeated from the spin-coating step to prepare 1 to 6 layers of PEDOT (1L to 6L of PEDOT) on a glass substrate 4. The temperatures of Cell 1 and the metal block 5 were controlled by constant temperature baths 7, 5.

[0077] The sheet resistance and surface morphology of the PEDOT film were monitored by changing the parameters of the VPP method. The remaining parameters of this method were kept constant while monitoring one specific parameter at a time. Polymerization was carried out by monitoring the VPP cell temperature, keeping the temperature in cell 1, which is the polymerization temperature, at 55 °C, 65 °C, 75 °C, and 85 °C, and using polymerization times of 2 minutes, 4 minutes, 6 minutes, and 8 minutes to prepare the PEDOT film. Although the VPP cell temperature and polymerization time were monitored, the substrate temperature was not controlled. The PEDOT film was prepared at different substrate temperatures from 45 °C to 75 °C. The temperature of the metal block 5 was controlled to change the substrate temperature. Annealing of the PEDOT film was carried out at 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, and 110 °C.

[0078] (Characteristic evaluation) A Raman spectrum (785 nm excitation) was recorded using a Qontor inVia Raman microscope manufactured by Renishaw. UV-Vis-NIR measurements were recorded using an Agilent 8453 (up to 1000 nm maximum) and a Cary 5E spectrophotometer (VARIAN) (up to 2400 nm maximum) (background correction was performed using an uncoated microscope glass slide). Using the Van der Pauw method, the sheet resistance (r sheet ) of 1 L to 6 L of PEDOT was calculated. The resistance value was recorded as the average of three measurements using a four-point probe (square with side a = 2.2 mm) and a Keithley multimeter (model 2000). The resistivity (r) and conductivity (s) of the film were calculated from equations (1) and (2).

[0079] AFM measurements were performed at room temperature using a Veeco diCaliber scanning probe microscope operating in tapping mode. All AFM images were recorded using a Bruker TESP-MT probe (resonant frequency 320 kHz, spring constant 42 N / m, length 125 μm, width 30 μm, cantilever specification: 0.01 - 0.025 Ωcm antimony (n)-doped silicon, thickness 4 μm, tip specification: height 10 - 15 μm, radius 8 nm). The average roughness (root mean square roughness (R a )) of the PEDOT film was determined using WSXM software.

[0080] CV and EIS techniques were used to determine the electrochemical properties. CV measurements were carried out in a conventional three-electrode configuration using 0.1 M TBA-BF4 / MeCN. PEDOT films prepared by VPP on glass slides covered with different numbers of PEDOT layers were used as the working electrode. The area of the working electrode was 1.13 cm 2 . An Ag / AgCl wire and a platinum wire were used as the reference electrode and counter electrode, respectively. The Ag / AgCl reference electrode was calibrated before and after electrochemical measurements using the ferrocene redox couple (E 1 / 2 (Fe / Fe + ) = 0.47 V). Cyclic voltammograms were recorded using a Metrohm Autolab potentiostat PGSTAT101 at a scan rate of 100 mV / s in the potential range of -0.25 V to 0.75 V for 1 L - 6 L of PEDOT. The charge (Q) was calculated by integrating the cyclic voltammogram in the potential range of -0.25 to 0.75 V using Origin software. This was further processed using equations (3) and (4) to obtain the capacitance value.

[0081] (Results) The effects of temperature on the sheet resistance and root mean square roughness of the PEDOT film are shown in Table 1. superposition

[0082] [Table 1] ​

[0083] The effects of temperature on the sheet resistance and average roughness of the PEDOT film are shown in Table 2. substrate The polymerization temperature is a factor that affects the properties of the resulting PEDOT film, such as the polymerization rate, by controlling the evaporation rate of the monomer (reactant), the mobility of the polymer chain, the conductivity, and the morphology. The average roughness (R

[0084] [Table 2]

[0085] ) of the PEDOT film increased with the increase in the temperature of the VPP cell 1 (Table 1). This increase in the average roughness is due to the high-concentration vapor at high temperature forcing the condensation of the vapor on the surface of the substrate. The prepared PEDOT film was very uniform and homogeneous. a ) increased with the increase in the temperature of the substrate (Table 2). This phenomenon is due to the rapid condensation of the monomer vapor at low temperature, resulting in a decrease in the film uniformity. As the temperature increases, the condensation rate decreases, leading to a more uniform film formation. The same behavior also explains the decrease in the sheet resistance of the PEDOT film with the increase in the substrate temperature up to 65 °C. The sheet resistance increased for the film prepared at 75 °C, which is due to less deposition of the monomer vapor because of the high substrate temperature.

[0086] The effects of the polymerization time on the sheet resistance and average roughness of the PEDOT film are shown in Table 3.

[0087] The effects of the polymerization time on the sheet resistance and average roughness of the PEDOT film are shown in Table 3.

[0088] [Table 3]

[0089] PEDOT films were prepared at different polymerization times, namely 2 minutes, 4 minutes, 6 minutes, and 8 minutes. The PEDOT film prepared during 6 minutes had the smallest average roughness value, and the PEDOT film prepared with a polymerization time of 4 minutes had the lowest sheet resistance (Table 3). The sheet resistance decreased after annealing. Films annealed at 60 °C, 70 °C, 80 °C, and 90 °C all showed similar sheet resistances. Since the sheet resistance decreases within the annealing temperature range of 60 °C to 90 °C, the completion of the curing and polymerization processes is guaranteed.

[0090] (Characterization of Multilayer PEDOT Films) Figure 2 shows the Raman spectrum of a 6-layer PEDOT film. The bands at 577, 699, 989, 1095, 1255, 1367, 1415, and 1530 cm -1 are assigned to oxyethylene ring deformation, symmetric C-S-C deformation, oxyethylene ring deformation, C-O-C deformation, C α -C α’ inter-ring stretching, C β -C β’ stretching, symmetric C α =C β (-O) stretching, and C α =C β stretching, respectively.

[0091] In Figure 3, 1L shows the AFM image of 1 layer of PEDOT, 2L shows the AFM image of 2 layers of PEDOT, 3L shows the AFM image of 3 layers of PEDOT, 4L shows the AFM image of 4 layers of PEDOT, 5L shows the AFM image of 5 layers of PEDOT, and 6L shows the AFM image of 6 layers of PEDOT. 1L, 3L, and 6L show the SEM images of PEDOT. Figure 3 shows the AFM images of PEDOT from 1L to 6L and the SEM images of 1L, 3L, and 6L, indicating that the properties of the film are in a very uniform and homogeneous sheet form. Materials used in optoelectronics need to have high surface smoothness. From the AFM images and the average roughness values (Table 4), it can be observed that for 1L of PEDOT, it does not exceed 1 nm, and for 6L of PEDOT, it does not exceed 4 nm. This indicates that even with a slight increase in surface roughness, the uniform and homogeneous sheet-like properties were not affected by the increment of additional layers. Thickness measurements were verified by averaging multiple measurements over a large scanning area of the PEDOT film. 1L of PEDOT has a conductivity of 2178 S / cm, and 6L of PEDOT has a maximum value of 3208 S / cm (Table 4). The vapor-phase polymerized PEDOT film prepared using FETOS as an oxidant forms densely packed large conductive regions that increase the in-plane conductivity. The sheet resistance decreases from 194.56 Ω / □ for 1L of PEDOT to 20.55 Ω / □ for 6L of PEDOT (Table 4). For 2L of PEDOT, the sheet resistance decreased by 57.7% from 1L of PEDOT but showed almost the same conductivity due to the increase in thickness. For 3L of PEDOT, the sheet resistance decreased by 35.4% from 2L of PEDOT, and the conductivity increased slightly. The decrease in sheet resistance when progressing from 3L of PEDOT to 6L of PEDOT is approximately linear, but 3L of PEDOT and 4L of PEDOT show almost the same conductivity values. The decrease in sheet resistance and the increase in conductance when progressing from 1L of PEDOT to 6L of PEDOT also indicate that charge moves rapidly from layer to layer (Table 4). This is facilitated by the efficient delocalization of polarons and polaron pairs or bipolaron PEDOT chains across different layers. This extended conjugation enables faster charge / electron movement across the film.

[0092] Table 4 shows the number of layers (L), thickness (d), sheet resistance (r sheet ), conductivity (s), areal capacitance (C A ), volume capacitance (C v ), percent transmittance (%T), and average roughness (R a ) of 1 - 6 layer PEDOT films fabricated by VPP.

[0093] [Table 4]

[0094] According to the conductive polaron theory, electron transport occurs through the motion of polarons and bipolaron / polaron pairs along the polymer chain, accompanied by the rearrangement of double and single bonds. As the doping level increases, the conductivity increases.

[0095] As can be seen from Table 4, a single layer of PEDOT is very transparent.

[0096] Figure 4 shows the cyclic voltammograms of 1L - 6L PEDOT (scan rate is 100 mV / s and contains 0.1 M TBABF4 in MeCN).

[0097] Figure 5 shows the cyclic voltammogram of 1L PEDOT on glass and on ITO - coated glass in a 6 mM ferrocene solution, with a scan rate of 20 mV / s.

[0098] In Figure 4, the rectangular - shaped cyclic voltammogram indicates a reversible and efficient charge - discharge process. Table 4 shows an increase in capacitance values for each layer of the PEDOT film. The 6 - layer film has 10.67 mF / cm 2 (areal capacitance) and 703.58 F / cm 3(Volume capacity) The capacity value was shown. In Fig. 5, the cyclic voltammogram of a single layer of PEDOT is compared with a bare ITO-coated glass in a 6 mM ferrocene solution. From the difference in peak potential, PEDOT needs to be 60 mV lower than the ITO-coated glass. The calculated charge values are 42.93 mC and 36.48 mC for 1 L of PEDOT and ITO-coated glass, respectively. This can be explained by the larger surface area of PEDOT compared to the ITO-coated glass. Overall, the ferrocene response of 1 L of PEDOT is superior to that of the ITO-coated glass.

[0099] Single-layer and multilayer PEDOT films are highly transparent, have a large surface area, high conductivity, and very low surface roughness, making them suitable for use as alternatives to optoelectronic devices and ITO coating materials.

[0100] It will be apparent to those skilled in the art that, with the progress of technology, the basic concepts can be implemented in various ways. Accordingly, the embodiments are not limited to the examples described above, but instead can be modified within the scope of the claims.

[0101] The above-described embodiments can be used in any combination with each other. It is also possible to combine some embodiments together to form further embodiments. The methods, conductive PEDOT films, optoelectronic devices, or uses disclosed herein can include at least one of the embodiments described above herein. It is understood that the above advantages and benefits can be related to one embodiment or to multiple embodiments. The embodiments are not limited to those that solve any or all of the problems described, or have any or all of the advantages and benefits described. Further, it should be understood that references to "one (an)" item refer to one or more of those items. The term "comprising" is used herein to mean including the subsequent features or acts without excluding the presence of one or more additional features or acts.

Claims

1. A method for manufacturing a poly(3,4-ethylenedioxythiophene) (PEDOT) film comprising a substrate and at least one PEDOT layer on at least one surface of the substrate, a) applying a solution containing an oxidizing agent and a base inhibitor onto at least one surface of the substrate to form an oxidizing agent coating on at least one surface of the substrate; b) subjecting the oxidizing agent-coated substrate formed in step a) to a polymerization step by exposing the surface of the oxidizing agent-coated substrate to 3,4-ethylenedioxythiophene (EDOT) monomer vapor at a polymerization temperature, thereby forming a PEDOT layer on the surface of the oxidizing agent-coated substrate; comprising, During the polymerization step, the polymerization temperature is 65 to 80 °C, the temperature of the oxidizing agent-coated substrate is maintained at a controlled substrate temperature, the controlled substrate temperature is 55 to 70 °C, and the method for manufacturing a PEDOT film is 3 to 20 °C lower than the polymerization temperature.

2. The method for manufacturing a PEDOT film according to claim 1, wherein the substrate is a non-conductive substrate.

3. The method for manufacturing the PEDOT film, c) applying the solution containing the oxidizing agent and the base inhibitor onto at least one surface of the PEDOT layer formed in step b) to form an oxidizing agent coating on at least one surface of the PEDOT layer; d) subjecting the oxidizing agent-coated PEDOT layer formed in step c) to a polymerization step by exposing the surface of the oxidizing agent-coated PEDOT layer to 3,4-ethylenedioxythiophene (EDOT) monomer vapor at a polymerization temperature, thereby forming a subsequent PEDOT layer on the surface of the oxidizing agent-coated PEDOT layer; comprising, During the polymerization step, the temperature of the oxidizing agent-coated PEDOT film is maintained at a controlled substrate temperature, and the controlled substrate temperature is 2 to 40 °C lower than the polymerization temperature. The method for manufacturing a PEDOT film according to claim 1 or 2.

4. The method for manufacturing a PEDOT film according to claim 3, wherein the method for manufacturing the PEDOT film includes repeating steps c) and d) at least once.

5. The temperature of the substrate coated with the oxidizing agent is maintained at a controlled substrate temperature during the polymerization step, and the controlled substrate temperature is 3 to 15 °C lower than the polymerization temperature. The method for producing a PEDOT film according to any one of claims 1 to 4.

6. The method for producing a PEDOT film according to any one of claims 1 to 5, wherein the method for producing the PEDOT film is vapor phase polymerization (VPP).

7. The temperature of the substrate coated with the oxidizing agent and / or the PEDOT film coated with the oxidizing agent is maintained at the controlled substrate temperature substantially throughout the polymerization step. The method for producing a PEDOT film according to any one of claims 1 to 6.

8. The polymerization step includes two consecutive treatment periods, and the temperature of the substrate coated with the oxidizing agent and / or the PEDOT film coated with the oxidizing agent is maintained at the controlled substrate temperature through one of the treatment periods. The method for producing a PEDOT film according to any one of claims 1 to 6.

9. The polymerization step includes three consecutive treatment periods, and the temperature of the substrate coated with the oxidizing agent and / or the PEDOT film coated with the oxidizing agent is maintained at the controlled substrate temperature through the middle treatment period. The method for producing a PEDOT film according to any one of claims 1 to 6 or 8.

10. The method for producing a PEDOT film according to any one of claims 1 to 9, including a step of cleaning the substrate before step a).

11. The solution containing the oxidizing agent 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). The method for producing a PEDOT film according to any one of claims 1 to 9.

12. The method for producing a PEDOT film according to any one of claims 1 to 11, including a step of cleaning, drying, and / or heating the substrate coated with the oxidizing agent before step b) and / or the PEDOT film from step c) before step d).

13. annealing the PEDOT film at a temperature of 50 to 100°C after overlapping, and optionally washing and drying the annealed PEDOT film, the method for manufacturing a PEDOT film according to any one of claims 1 to 12.

14. Before step c), including the step of washing the PEDOT film received from step b), the method for manufacturing a PEDOT film according to any one of claims 3 to 13.

15. The method for manufacturing a PEDOT film according to any one of claims 1 to 14, wherein the duration of the polymerization step is 1 to 20 minutes.

16. The temperature of the substrate coated with an oxidizing agent and / or the PEDOT film coated with an oxidizing agent is maintained at a controlled substrate temperature, and the duration of the polymerization step treatment period is 20 to 80% of the duration of the polymerization step, the method for manufacturing a PEDOT film according to any one of claims 1 to 15.

17. The method for manufacturing a PEDOT film according to any one of claims 2 to 16, wherein the non-conductive substrate is glass or polyethylene terephthalate (PET).

18. The method for manufacturing a PEDOT film according to any one of claims 1 to 15, wherein the oxidizing agent is iron(III) p-toluenesulfonate hexahydrate (FETOS).

19. The method for manufacturing a PEDOT film according to any one of claims 1 to 18, wherein the base inhibitor is pyridine.

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