N-doped PEDOT thin film and method for preparing the same

Abstract

The application belongs to the technical field of thermoelectric materials, and particularly relates to an N-doped PEDOT conductive film and a preparation method thereof. The N-doped PEDOT conductive film is obtained through a continuous liquid-phase polymerization method of materials. Specifically, an oxidation layer film is first processed, and then the prepared oxidation layer film is placed into an EDOT monomer reaction solution to perform a polymerization reaction, so that the N-doped PEDOT conductive film is prepared.

Description

Technical Field

[0001] This invention belongs to the field of thermoelectric materials technology, specifically relating to an N-type doped PEDOT conductive thin film and its preparation method. Background Technology

[0002] Thermoelectric materials are novel semiconductor materials that directly convert thermal energy into electrical energy by utilizing temperature differences to drive the directional movement of charge carriers within the material. They have significant application value in fields such as thermoelectric power generation and portable refrigeration. Thermoelectric functional materials are green energy materials that can directly convert heat and electricity through the migration of charge carriers within a solid. Unlike traditional methods that utilize the chemical energy released from fuel combustion to convert into mechanical energy and then into electrical energy, thermoelectric materials and devices can output a continuous and stable voltage without the need for other components. The use of traditional energy sources leads to environmental pollution, ozone layer depletion, and exacerbation of the greenhouse effect. Thermoelectric materials, on the other hand, can directly convert thermal energy into electrical energy, causing almost no pollution or damage to the environment.

[0003] Conductive polymers are polymers whose main chains possess a conjugated primary electron system. They can achieve a conductive state through doping (i.e., adding small amounts of other elements or compounds to the material or matrix to improve its properties), with conductivity exceeding 1000 S / cm. Their structures share certain common characteristics, namely, an alternating -CC- and -C=C- conjugated structure, formed by long-chain carbon molecules linked by sp2 bonds. Due to the properties of sp2 bonds, each carbon atom has one unpaired valence electron, forming an unpaired bond perpendicular to the sp2 plane. The electron clouds of unpaired bonds between adjacent atoms are in contact, allowing electrons to move easily within this structure, thus exhibiting conductivity.

[0004] PN junctions are indispensable in various thermoelectric devices and electronic components. The development of high-performance P-type and N-type organic polymer semiconductors has a significant impact on the entire field of organic electronics. P-type semiconductors, also known as hole-type semiconductors, rely primarily on free electrons for conductivity. The more impurities incorporated, the higher the hole concentration and the stronger the conductivity. N-type semiconductors, also known as electron semiconductors, primarily conduct electricity through free electrons. The more impurities incorporated, the higher the free electron concentration and the stronger the conductivity. However, due to their poor environmental stability, steric hindrance, and limitations in synthesis methods, N-type semiconductors have been studied relatively little.

[0005] Traditional PEDOT thin films are generally P-type semiconductors, primarily used for hole transport. For example, Chinese patent application CN202310156271.5 discloses a memristor based on a GaN / PEDOT:PSS planar heterojunction, where the PEDOT:PSS organic layer is P-type conductive. Chinese patent application CN202110533460.0 discloses an ultra-flexible self-generating yarn and electrowoven fabric, which is a P-type thermoelectric material composed of PEDOT:PSS and an ionic liquid. Chinese patent application CN202111210818.2 discloses a PEDOT:PSS / VNO.52O0.26 thermoelectric composite film, which discloses a method for constructing a pn junction barrier of P-type PEDOT:PSS and N-type VNO.52O0.26 nanoparticles. Furthermore, there are currently no reports on pure N-type PEDOT in the literature. Existing literature shows that PEDOT is doped with N-type semiconductor materials, such as polyethyleneimine (PEI), for example, the literature Poly(phthalazinone ether ketone)–Poly(3,4-ethylenedioxythiophene)fiber for thermoelectric and hydroelectric energy harvesting Chemical Engineering Journal 450(2022)138093.

[0006] In summary, it is necessary to propose a new PEDOT conductive thin film and its preparation method to prepare a high-performance N-type semiconductor. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide an N-type doped PEDOT conductive thin film, its preparation method and application, and the specific technical solution is as follows.

[0008] A method for preparing an N-type doped PEDOT conductive film, wherein the N-type doped PEDOT conductive film is obtained by continuous liquid-phase polymerization of materials. Specifically, an oxide layer film is first processed, and then the prepared oxide layer film is placed in an EDOT monomer reaction solution for polymerization. The specific steps are as follows:

[0009] Step 1: Prepare an adhesive layer on a clean substrate: The materials used to prepare the adhesive layer include 3-aminopropyltriethoxysilane and polyurethane;

[0010] Step 2: Preparation of oxide layer (film): The oxidant is dissolved in deionized water by stirring and then applied to the adhesive layer obtained in step 1) to obtain an oxide layer. The oxidant is hydrated vanadium pentoxide.

[0011] Step 3: Preparation of EDOT monomer reaction precursor solution: Add organic solvent, acid solution containing hydrogen ions and EDOT monomer in sequence and mix evenly to prepare EDOT monomer reaction precursor solution. The volume ratio of each component in the EDOT monomer reaction precursor solution is organic solvent: acid solution: EDOT = 100-900: 1-20: 100-900.

[0012] Step 4: Preparation of EDOT monomer reaction solution: Dimethyl sulfoxide (DMSO) is further added to the EDOT monomer reaction precursor solution prepared in Step 3, wherein the volume ratio of the EDOT monomer reaction precursor solution to the dimethyl sulfoxide is 1:0.05-1.

[0013] Step 5: Place the oxide layer prepared in Step 2 into the EDOT monomer reaction solution prepared in Step 4 for polymerization (EDOT monomers undergo polymerization in the presence of oxidant (vanadium pentoxide) and initiator (acid);

[0014] Step 6: After the polymerization reaction in Step 5, the substrate is immersed in dilute hydrochloric acid and methanol in sequence to remove impurities, thereby obtaining the N-type doped PEDOT conductive film.

[0015] Furthermore, the acid solution containing hydrogen ions includes sulfonic acids, carboxylic acids, and hydrochloric acid, etc.

[0016] The acid solution described above can provide the hydrogen ions needed to promote the polymerization reaction.

[0017] Furthermore, the method for preparing the adhesive layer in step 1 includes spin coating, drop coating, blade coating, slot coating, or inkjet printing (and any other form of film-forming technology).

[0018] Furthermore, the substrate in step 1 includes rigid substrates and flexible substrates, including ordinary glass, ITO conductive glass, quartz or PET, etc.

[0019] Furthermore, the molar concentration of the oxidant in step 2 is 0.1-0.5 mol / L.

[0020] Furthermore, the method for preparing the oxidant on the adhesive layer in step 2 includes spin coating, drop coating, blade coating, slot coating, or inkjet printing (and any other form of film-forming technology).

[0021] Furthermore, the organic solvent in step 3 includes one or more of methanol, ethanol, and isopropanol.

[0022] Furthermore, the molar concentration of the EDOT monomer in step 3 is 0.1-6.6 mol / L.

[0023] The N-type doped PEDOT conductive film prepared by the above preparation method.

[0024] The above-mentioned N-type doped PEDOT conductive films are used in the fabrication of thermoelectric devices.

[0025] Beneficial technical effects

[0026] This invention innovatively prepares N-type doped PEDOT thin films, realizing the transformation of PEDOT conductive polymer from a P-type semiconductor (i.e., a hole-type semiconductor) to an N-type semiconductor (an electron-type semiconductor). The Seebeck coefficient of the PEDOT thin film prepared by this invention changes from positive to negative, proving that the transformation from P-type to N-type has been achieved, thus enabling electron transport. Patent application CN202210569859.9, entitled "A Method for Improving the n-type Ion Thermal Voltage Performance of PEDOT:PSS Thin Films," discloses a method for preparing a PEDOT:PSS thin film material with high-performance n-type ion thermal voltage through direct mixing of material solutions. In this material, PEDOT:PSS itself forms a P-type thermal voltage, but PSS dissociates into hydrogen ions. Therefore, after adding a specific organic guanidine salt, since the organic guanidine salt can provide anions and cations, and its concentration is much greater than the concentration of hydrogen ions dissociated from PSS, the thermal voltage formed by hydrogen ion migration is offset, ultimately increasing the ion thermal voltage. The present invention directly synthesizes an N-type doped PEDOT thin film with electron transport as its main function by adding DMSO and using a continuous liquid-phase polymerization method.

[0027] Finally, the method for preparing N-type doped PEDOT thin films provided by this invention is simple, fast, and inexpensive, and can be achieved without special large-scale instruments and equipment, thus having good prospects for industrial application. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. The elements or parts in the drawings are not necessarily drawn to scale. Obviously, the drawings described below are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0029] Figure 1 This is a schematic diagram of the preparation method of the present invention;

[0030] Figure 2 Image of an N-type doped PEDOT thin film prepared by the method of the present invention;

[0031] Figure 3 The Seebeck coefficient test results of an N-type doped PEDOT thin film prepared according to one embodiment of the present invention;

[0032] Figure 4 The Seebeck coefficient test results are for an N-type doped PEDOT thin film prepared according to one embodiment of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] In this document, "and / or" includes any and all combinations of one or more of the listed related items.

[0035] In this article, "multiple" means two or more, that is, it includes two, three, four, five, etc.

[0036] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0037] As used in this specification, the term "about" typically means + / - 5% of the value, more typically + / - 4%, more typically + / - 3%, more typically + / - 2%, even more typically + / - 1%, even more typically + / - 0.5% of the value.

[0038] In this specification, certain embodiments may be disclosed in a range-bound format. It should be understood that this "range-bound" description is merely for convenience and brevity and should not be construed as a rigid limitation on the disclosed range. Therefore, the description of the range should be considered as having specifically disclosed all possible subranges and independent numerical values ​​within those ranges. For example, range The description should be considered as having specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within this range, such as 1, 2, 3, 4, 5, and 6. The above rules apply regardless of the breadth of the range.

[0039] The "continuous liquid phase polymerization" described in this invention belongs to an in-situ polymerization method, which is different from mixed polymerization followed by processing. Specifically, it refers to the sequential processing of the oxide layer and EDOT monomer, and finally the prepared oxide layer and EDOT monomer reaction solution are placed together for polymerization. In this invention, both the oxidant and EDOT monomer are processed in the liquid phase.

[0040] Example 1

[0041] In this example, V2O5 was purchased from West Asia Reagent Company, and EDOT monomer was purchased from Adamas Reagent Company.

[0042] 1) Create the adhesive layer

[0043] 3-Aminopropyltriethoxysilane (APTES) and polyurethane (WPU) were spin-coated and annealed onto a clean substrate to obtain an adhesive layer;

[0044] During the spin coating process, the spin coating speed is 4000 rpm and the time is 30 seconds.

[0045] During the annealing process: the annealing temperatures were 120℃ and 80℃ respectively, and the annealing times were 10 min and 30 min respectively.

[0046] 2) Fabrication of the oxide layer

[0047] The oxidant hydrated vanadium pentoxide (HVO) was dissolved in deionized (DI) water and then spin-coated and annealed onto the adhesive layer obtained in step 1) to obtain an oxide layer.

[0048] The concentration of the hydrated V2O5 oxidant is 0.1-0.5 mol / L.

[0049] During the process of dissolving the oxidant, the stirring rate was 1000 rpm and the dissolution time was 18 hours.

[0050] During the spin coating process, the spin coating speed is 1500 rpm and the time is 45 s.

[0051] During the annealing process, the annealing temperature is 80℃ and the annealing time is 10 minutes.

[0052] 3) Prepare EDOT monomer reaction precursor solution

[0053] 1800 μL of methanol (MeOH), 10 μL of methanesulfonic acid (MSA), and 200 μL of EDOT monomer were added sequentially and mixed evenly to prepare the EDOT monomer reaction precursor solution. In this example, the volume ratio of each component was methanol:methanesulfonic acid:EDOT = 900:5:100.

[0054] 4) Prepare EDOT monomer reaction solution

[0055] Add 200 μL of dimethyl sulfoxide (DMSO) solution to the prepared EDOT monomer reaction precursor solution and mix thoroughly to form the EDOT monomer reaction solution; in this embodiment, the volume ratio of EDOT monomer reaction precursor solution to dimethyl sulfoxide solution is approximately 1:0.1.

[0056] 5) Film formation of PEDOT

[0057] The oxide layer obtained in step 2) is placed in the EDOT monomer solution obtained in step 4) and polymerized for 1 hour.

[0058] 6) Post-processing of PEDOT film

[0059] The reacted substrate was immersed in 0.1% mol / L dilute hydrochloric acid for 10 minutes to remove residual oxidant and unreacted EDOT. Then it was immersed in methanol for 10 minutes to obtain an N-type doped PEDOT conductive film.

[0060] Example 2

[0061] 1) Create the adhesive layer

[0062] 3-Aminopropyltriethoxysilane (APTES) and polyurethane (WPU) were spin-coated and annealed onto a clean substrate to obtain an adhesive layer;

[0063] During the spin coating process, the spin coating speed is 4000 rpm and the time is 30 seconds.

[0064] During the annealing process, the annealing temperatures were 120℃ and 80℃ respectively, and the annealing times were 10 min and 30 min respectively.

[0065] 2) Fabrication of the oxide layer

[0066] The oxidant hydrated V2O5 was dissolved in deionized (DI) water and then spin-coated and annealed onto the adhesive layer obtained in step 1) to obtain the oxidant precursor.

[0067] The concentration of the hydrated V2O5 oxidant is 0.1-0.5 mol / L.

[0068] During the process of dissolving the oxidant, the stirring rate was 1000 rpm and the dissolution time was 9 hours.

[0069] During the spin coating process, the spin coating speed is 1500 rpm and the time is 45 s.

[0070] During the annealing process, the annealing temperature is 80℃ and the annealing time is 10 minutes.

[0071] 3) Prepare EDOT monomer reaction precursor solution

[0072] 1800 μL of methanol, 10 μL of methanesulfonic acid, and 200 μL of EDOT monomer were added sequentially and mixed evenly to prepare the EDOT monomer reaction precursor solution. In this example, the volume ratio of each component was organic solvent: methanesulfonic acid: EDOT = 900:5:100.

[0073] 4) Prepare EDOT monomer reaction solution

[0074] 200 μL of dimethyl sulfoxide (DMSO) solution was added to the prepared EDOT monomer reaction precursor solution and mixed thoroughly to form the EDOT monomer reaction solution; in this embodiment, the volume ratio of EDOT monomer reaction precursor solution to dimethyl sulfoxide solution was 1:0.1.

[0075] 5) Film formation of PEDOT

[0076] The oxide layer obtained in step 2) is placed in the EDOT monomer solution obtained in step 4) and polymerized for 1 hour.

[0077] 6) Post-processing of PEDOT film

[0078] The reacted substrate was immersed in 0.1 mol / L dilute hydrochloric acid for 10 min to remove residual oxidant and unreacted EDOT, and then immersed in methanol for 10 min to obtain N-type doped PEDOT conductive film.

[0079] The electrical properties of the N-type doped PEDOT conductive films prepared in Examples 1 and 2 are shown in the table below.

[0080] Table 1

[0081] Conductivity S / cm Seebeck coefficient μV / K Example 1 1.29 -35.31 Example 2 0.67 -20.76

[0082] Both Examples 1 and 2 successfully prepared N-type doped PEDOT films, with their Seebeck coefficient changing from positive to negative, demonstrating the achievement of the P-type to N-type transition. The dissolution times of the oxidant differed between Examples 1 and 2; experiments showed that the more fully the oxidant dissolved, the better the conductivity.

[0083] This invention innovatively incorporates DMSO into the synthesis of PEDOT, thereby achieving the transformation of PEDOT films from P-type to N-type. The following table shows the conductivity and Seebeck coefficient results of PEDOT films prepared with different proportions of DMSO.

[0084] Table 2. Volume ratio of different EDOT monomer reaction precursor solutions to DMSO

[0085] MeOH:MSA:EDOT:DMSO Conductivity S / cm Seebeck coefficient μV / K 900:5:100:100 0.39 -20.92 900:5:100:300 0.0019 -99.40 900:5:100:500 0.00036 -2.89 500:5:100:500 0.0014 -81.56

[0086] Example 3

[0087] This embodiment provides another example of synthesizing the N-type doped PEDOT thin film of the present invention.

[0088] Create adhesive layer

[0089] 3-Aminopropyltriethoxysilane (APTES) and polyurethane (WPU) were drop-coated onto a cleaned substrate to obtain an adhesive layer;

[0090] During the drop coating process, the solution is dropped onto the substrate one drop at a time, covering the entire substrate, and then heated to dry using a hot plate at 100°C.

[0091] During the annealing process, the annealing temperatures were 120℃ and 80℃ respectively, and the annealing times were 10 min and 30 min respectively.

[0092] 2) Fabrication of the oxide layer

[0093] The oxidant hydrated vanadium pentoxide (HVO) was dissolved in deionized (DI) water and then dripped onto the adhesive layer prepared in step 1) to obtain the oxide layer.

[0094] The concentration of the hydrated V2O5 oxidant is 0.1-0.5 mol / L.

[0095] During the process of dissolving the oxidant, the stirring rate is 1000 rpm and the dissolution time is 9-18 h.

[0096] During the drop coating process, the solution is dropped onto the substrate one drop at a time, covering the entire substrate, and then heated to dry using a hot plate at 80°C.

[0097] During the annealing process, the annealing temperature is 80℃ and the annealing time is 10 minutes.

[0098] 3) Prepare EDOT monomer reaction precursor solution

[0099] 1800 μL of ethanol, 10 μL of carboxylic acid, and 200 μL of EDOT monomer were added sequentially and mixed evenly to prepare the EDOT monomer reaction precursor solution. In this example, the volume ratio of each component was ethanol:carboxylic acid:EDOT = 900:5:100.

[0100] 4) Add 200 μL of dimethyl sulfoxide (DMSO) solution to the prepared EDOT monomer reaction precursor solution and mix well to form the EDOT monomer reaction solution; in this example, the volume ratio of EDOT monomer reaction precursor solution to dimethyl sulfoxide solution is approximately 1:0.1.

[0101] 5) Film formation of PEDOT

[0102] The oxide layer obtained in step 2) is placed in the EDOT monomer solution obtained in step 4) and polymerized for 1 hour.

[0103] 5) Post-processing of PEDOT film

[0104] The reacted substrate was immersed in 0.1% mol / L dilute hydrochloric acid for 10 minutes to remove residual oxidant and unreacted EDOT. Then it was immersed in methanol for 10 minutes to obtain an N-type doped PEDOT conductive film.

[0105] Example 4

[0106] This embodiment provides another example of synthesizing the N-type doped PEDOT thin film of the present invention.

[0107] Create adhesive layer

[0108] 3-Aminopropyltriethoxysilane (APTES) and polyurethane (WPU) were coated onto a cleaned substrate to obtain an adhesive layer;

[0109] During the coating process, the coating speed is 5 mm / s.

[0110] During the annealing process, the annealing temperatures were 120℃ and 80℃ respectively, and the annealing times were 10 min and 30 min respectively.

[0111] 2) Fabrication of the oxide layer

[0112] The oxidant hydrated vanadium pentoxide (HVO) was dissolved in deionized (DI) water and then coated onto the adhesive layer prepared in step 1) to obtain the oxide layer.

[0113] The concentration of the hydrated V2O5 oxidant is 0.1-0.5 mol / L.

[0114] During the process of dissolving the oxidant, the stirring rate is 1000 rpm and the dissolution time is 9-18 h.

[0115] During the coating process, the coating speed is 5 mm / s.

[0116] 3) Prepare EDOT monomer reaction precursor solution

[0117] 1800 μL of isopropanol, 10 μL of carboxylic acid, and 200 μL of EDOT monomer were added sequentially and mixed evenly to prepare the EDOT monomer reaction precursor solution. In this example, the volume ratio of each component was isopropanol:carboxylic acid:EDOT = 900:5:100.

[0118] 4) Add 200 μL of dimethyl sulfoxide (DMSO) solution to the prepared EDOT monomer reaction precursor solution and mix well to form the EDOT monomer reaction solution; in this example, the volume ratio of EDOT monomer reaction precursor solution to dimethyl sulfoxide solution is approximately 1:0.1.

[0119] 5) Film formation of PEDOT

[0120] The oxide layer obtained in step 2) is placed in the EDOT monomer solution obtained in step 4) and polymerized for 1 hour.

[0121] 5) Post-processing of PEDOT film

[0122] The reacted substrate was immersed in 0.1% mol / L dilute hydrochloric acid for 10 minutes to remove residual oxidant and unreacted EDOT. Then it was immersed in methanol for 10 minutes to obtain an N-type doped PEDOT conductive film.

[0123] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for preparing an N-type doped PEDOT conductive thin film, characterized in that, The N-type doped PEDOT conductive film is obtained by a continuous liquid-phase polymerization method, the specific steps of which are as follows: Step 1: Prepare an adhesive layer on a clean substrate: The materials used to prepare the adhesive layer include 3-aminopropyltriethoxysilane and polyurethane; Step 2: Preparation of oxide layer: The oxidant is dissolved in deionized water and then applied to the adhesive layer obtained in step 1) to obtain an oxide layer. The oxidant is hydrated vanadium pentoxide. Step 3: Preparation of EDOT monomer reaction precursor solution: Add organic solvent, acid solution containing hydrogen ions and EDOT monomer in sequence and mix evenly to prepare EDOT monomer reaction precursor solution. The volume ratio of each component in the EDOT monomer reaction precursor solution is organic solvent: acid solution: EDOT = 100-900: 1-20: 100-900. Step 4: Prepare EDOT monomer reaction solution: Add dimethyl sulfoxide to the EDOT monomer reaction precursor solution prepared in step 3, wherein the volume ratio of the EDOT monomer reaction precursor solution to the dimethyl sulfoxide is 1:0.05~1; Step 5: Place the oxide layer prepared in Step 2 into the EDOT monomer reaction solution prepared in Step 4 for polymerization reaction; Step 6: After the polymerization reaction in Step 5, the substrate is immersed in dilute hydrochloric acid and methanol in sequence to remove impurities, thereby obtaining the N-type doped PEDOT conductive film.

2. The preparation method according to claim 1, characterized in that, The acid solutions containing hydrogen ions include sulfonic acids, carboxylic acids, and hydrochloric acid.

3. The preparation method according to claim 1, characterized in that, The method for preparing the adhesive layer in step 1 includes spin coating, drop coating, blade coating, slot coating, or inkjet printing.

4. The preparation method according to claim 1, characterized in that, The substrate in step 1 includes rigid substrates and flexible substrates, including ordinary glass, ITO conductive glass, quartz or PET.

5. The preparation method according to claim 1, characterized in that, The molar concentration of the oxidant in step 2 is 0.1-0.5 mol / L.

6. The preparation method according to claim 1, characterized in that, The method for preparing the oxidant on the adhesive layer in step 2 includes spin coating, drop coating, blade coating, slot coating, or inkjet printing.

7. The preparation method according to claim 1, characterized in that, The organic solvent in step 3 includes one or more of methanol, ethanol, and isopropanol.

8. The preparation method according to claim 1, characterized in that, The molar concentration of EDOT monomer in the EDOT monomer reaction precursor solution in step 3 is 0.1-6.6 mol / L.

9. The N-type doped PEDOT conductive film prepared by the preparation method according to any one of claims 1-8.

10. The application of the N-type doped PEDOT conductive film according to claim 9 in the fabrication of thermoelectric devices.

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