One-step method for obtaining an ink containing an N-type conductive polymer.

Abstract

The present invention relates to a method for producing an ink comprising an n-type conductive polymer, a) A step of preparing a catalyst or catalyst precursor, b) A step of obtaining the catalyst by oxidizing the catalyst precursor with an oxidation accelerator, c) A step of adding a monomer to a solvent system containing a polar aprotic solvent in the presence of the above catalyst to obtain a reaction solution, d) A step of polymerizing the above monomer in the above reaction solution to obtain an ink containing an n-type conductive polymer, It includes, The present invention relates to a method wherein the catalyst is a quinone comprising at least one branched side chain comprising at least one chiral center.

Description

[Technical Field]

[0001] The present invention relates to a method for producing an ink comprising an n-type conductive polymer, and to an ink comprising an n-type conductive polymer obtained by such a method. [Background technology]

[0002] Conductive polymers (CPs) are attracting widespread attention due to their flexibility, low-cost solution processing capabilities, and multifunctional properties, including electrochemical redox activity. These properties make CPs suitable for a wide range of applications in the electronics field, particularly in flexible electronics, wearable technology, and flexible displays. Among CPs, PEDOT:PSS is one of the most studied materials due to its excellent electro-optic properties and high conductivity. Secondary doping allows for conductivity of 1000 S cm. -1 It is possible to achieve conductivity exceeding [a certain level].

[0003] Generally, PEDOT can be prepared by polymerization using chemical oxidation or electrochemical processes. Preparation of PEDOT by chemical oxidation processes yields higher yields and does not require special setup. Although PEDOT is highly conductive, it is difficult to process due to its insolubility in water. However, this problem can be solved by using polymer electrolytes such as polystyrene sulfonic acid (PSS), which acts as a dopant and stabilizer for PEDOT through charge balance. PEDOT:PSS has good transparency, low density, low thermal conductivity, high thermal stability, good compatibility, flexibility, and low production costs. It has diverse applications in flexible electronics, organic solar cells, supercapacitors, electrochemical transistors, and light-emitting diodes. However, many of these applications require devices that use both hole-transporting (p-type) and electron-transporting (n-type) materials to achieve optimal performance.

[0004] In recent years, significant progress has been made in the development of high-performance n-type conductive polymers. However, the synthesis processes for some n-type conductive polymers have low yields, thus reducing cost-effectiveness. Furthermore, the synthesis of n-type conductive polymers requires the use of toxic solvents, which are harmful to the environment and the health of workers.

[0005] Chinese Patent No. 115651448 describes the synthesis of polybenzodiflaione (PBFDO), an n-type conductive polymer known for its excellent conductivity. However, the synthesis route disclosed in Chinese Patent No. 115651448 requires approximately two weeks of post-dialysis treatment, and the polymerization process uses non-recyclable catalysts derived from fossil resources.

[0006] Therefore, there is a need to develop improved methods for producing inks comprising n-type conductive polymers, particularly those containing renewable and environmentally friendly catalysts. [Overview of the project]

[0007] Considering the above, the present invention aims to solve the problems of the prior art. For this purpose, the present invention provides a method for producing an ink comprising an n-type conductive polymer, a) A step of preparing a catalyst or catalyst precursor, b) A step of obtaining the catalyst by oxidizing the catalyst precursor with an oxidation accelerator, c) A step of adding a monomer to a solvent system containing a polar aprotic solvent in the presence of the above catalyst to obtain a reaction solution, d) A step of polymerizing the above monomer in the above reaction solution to obtain an ink containing an n-type conductive polymer, The present invention relates to a method comprising the above.

[0008] The catalyst described above is a quinone comprising at least one branched side chain and at least one chiral center located on the at least one branched side chain. The catalyst precursor is a quinone precursor, i.e., a species capable of forming a quinone structure. The side chain may comprise 3 to 100 carbon atoms. The side chain may further comprise at least one functional group, such as a hydroxyl group. Furthermore, the side chain may further comprise a branched center. The catalyst according to the present invention has been demonstrated not to crystallize during polymerization reactions because the at least one branched side chain comprising at least one chiral center prevents such crystallization. Since the catalyst does not crystallize, the dialysis step is eliminated.

[0009] Note that if the catalyst is prepared in step a), step b) is essentially omitted. If step b) exists, it can be performed before or simultaneously with step c).

[0010] The term "oxidation accelerator" refers to a species or method that can induce oxidation.

[0011] Therefore, one advantage of the method of the present invention is that the catalyst according to the present invention does not crystallize because it has at least one branched side chain comprising at least one chiral center, thus eliminating the need for a dialysis step to remove the catalyst.

[0012] The above heteromonomers have a centrally symmetric benzene ring as a skeleton, active hydrogen, and at least one electron-withdrawing group at the benzyl position. Examples of the electron-withdrawing group include carbonyl, carboxyl, amide, alkoxyacyl, or the same. [ka]

[0013] Furthermore, the monomer may be in the form of a heterocyclic moiety having at least one, preferably at least two, rings, preferably 5-membered rings, condensed with a centrosymmetric benzene ring. The monomer further comprises an active hydrogen and at least one electron-withdrawing group at the benzylic position. In particular, the monomer may be 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (HBFDO), 5,7-dihydropyrrolo[2,3-f]indole-2,6(1H,3H)-dione, or 3,7-dihydrobenzo[1,2-b:4,5-b']dithiophene-2,6-dione. [Chemical formula]

[0014] In particular, the monomer is 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (HBFDO). In such an embodiment, the n-type conductive polymer is polybenzodifurandione (PBFDO).

[0015] According to a particular embodiment, the catalyst precursor may be vitamin E. As is well known in the art, vitamin E is a group of eight fat-soluble compounds including four tocopherols and four tocotrienols, as shown below. [Chemical formula]

[0016] It should be noted that according to the method of the present invention, the term vitamin E means at least one of the above species. In other words, each of the above species may be present in pure form in the reaction solution, or at least two of the above species may be present in any combination. Thus, vitamin E can be selected from the group consisting of α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, α-tocotrienol, β-tocotrienol, γ-tocotrienol, δ-tocotrienol, and mixtures thereof.

[0017] Vitamin E (a collective term for tocopherols and tocotrienols) is a natural product with high redox activity. Vitamin E is synthesized in photosynthetic plants and can be extracted in large quantities from plants. All vitamin E molecules have branched, long hydrocarbon side chains and are natural oily substances that do not crystallize at room temperature. According to the method of the present invention, an ink containing an n-type conductive polymer can be synthesized in one step (one process) or one pot without requiring post-treatment such as dialysis and solvent removal, using vitamin E as a catalytic precursor. Compared to the three-step method reported in the prior art literature specified above, the method of the present invention achieves a significant simplification.

[0018] Surprisingly, it was found that vitamin E itself does not have catalytic activity, but its oxidized form does. In the presence of an oxidation accelerator, vitamin E forms a benzoquinone derivative. As mentioned above, the oxidation of vitamin E may be carried out before adding the monomer. Alternatively, the oxidation of vitamin E may occur in situ during step c). When the catalyst, for example, oxidized vitamin E, comes into contact with the monomer, the polymerization reaction is initiated. Therefore, the method of the present invention offers the advantage of being a simplified and cost-effective method for producing an ink comprising an n-type conductive polymer compared to methods known in the art. The major advantages of using vitamin E as a catalytic precursor are its availability, low cost, and non-toxicity.

[0019] At least one branched side chain of the catalyst according to the present invention may be a saturated branched side chain.

[0020] Note that catalysts are sometimes referred to as initiators, especially when used in polymerization.

[0021] In certain embodiments, the polar aprotic solvent is DMSO, and the oxidation accelerator is hydrogen bromide (HBr). HBr is volatile and does not affect film formation when the ink is printed. The DMSO may be industrial-grade DMSO, i.e., it may contain water.

[0022] Alternatively, the above-mentioned oxidation accelerator is an ionic liquid comprising cations and anions. In such embodiments, the above method is a') Step of electrolyzing the above reaction solution. It further includes, Step a') is performed simultaneously with or after step c). In such embodiments, the oxidation is electrochemical oxidation.

[0023] In particular, step a') can be performed using a nickel cathode and a carbon anode, at a voltage in the range of 4 to 6 V for a period of 10 to 60 minutes.

[0024] The cation in the above ionic liquid can be selected from the group consisting of 1-ethyl-3-methylimidazolium (EMIM), 1-butyl-3-methylimidazolium (BMIM), 1-allyl-3-methylimidazolium (AMIM), 1-hexyl-3-methylimidazolium (HMIM), butylmethylpyrrolidinium (BMP), propylmethylpyrrolidinium (PMP), triethylsulfonium, and mixtures thereof. The structure of the above cation is shown below. [ka]

[0025] According to the present invention, the above anion is a chloride (Cl - ), bromide (Br - ), iodide (I - ), acetic acid (OAc), tetrafluoroboric acid (BF4 - ), hexafluorophosphate (PF6 -) Bistrifluoromethanesulfonimide (TFSI), trifluoromethanesulfonic acid (OTf), dicyanamide (DCA), hydrogen sulfate (HSO4 - ) Ethyl sulfate (ESO4 - ) Thiocyanate (SCN), tosylate (OTs), mesylate (OMs), tetrachloroaluminate (AlCl4 - ) Diethyl phosphate (DEP), dimethyl phosphate (DMP), lactate (La), L-alanine anion (APP), and mixtures thereof. The structures of the above anions are shown below. [Chemical formula]

[0026] As described above, the solvent system according to the method of the present invention comprises a polar aprotic solvent. The polar aprotic solvent can be dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMA), or a combination thereof.

[0027] The ratio of the oxidation promoter and vitamin E in step b) is in the range of 0.1 to 100, preferably 0.25 to 5, more preferably 1 to 3.

[0028] The polymerization reaction, i.e., step d) of the method of the present invention, can occur at a temperature of 5°C to 200°C, preferably 18°C to 180°C.

[0029] The polymerization reaction, i.e., step d) of the method of the present invention, can be carried out for a time of 10 minutes to 72 hours. For example, when step d) is carried out at 100°C, the reaction is completed after 1 hour as indicated by the change in color and viscosity of the reaction solution. On the other hand, when step d) is carried out at room temperature, a color change is observed after about 72 hours. The temperature of the reaction solution at the start of step d) is 25°C and can be raised to 100°C thereafter. Alternatively, the temperature of the reaction solution at the start of step d) is 100°C and may be maintained at that temperature throughout step d).

[0030] Steps a) to d) of the method according to the present invention may be carried out under ambient conditions, i.e., in air at a temperature of 20°C to 25°C. Preferably, at least step d) is carried out in an inert atmosphere, i.e., under nitrogen or argon.

[0031] In order to further improve the cost efficiency of the method according to the present invention, the method according to the present invention is e) A process of removing the catalyst by extraction and recycling the catalyst. It may further include the following.

[0032] Extraction can be carried out using alkanes or ethers.

[0033] The overall outline of the method of the present invention can be summarized as follows: [ka]

[0034] The present invention further relates to an ink comprising an n-type conductive polymer manufactured by the above method.

[0035] The n-type conductive ink of the present invention can be deposited by spin coating, drop casting, inkjet printing, or screen printing. Therefore, the n-type conductive ink can be spin coated or drop cast in air and at ambient temperature to form a film with a thickness of 1 nm to 1 cm, more preferably 10 nm to 10 μm. Such a film can exhibit an electrical conductivity of at least 10 S / cm, preferably at least 1000 S / cm, and more preferably at least 5000 S / cm.

[0036] The n-type conductive ink of the present invention may have shear-induced viscosity reduction. In particular, when the PBFDO content in the n-type conductive ink is 0.67% by weight, the viscosity range may be in the range of 0.007 to 32 Pa·s. When the weight content is high and / or the shear rate is low, the viscosity value may be even higher.

[0037] As described above, the n-type conductive ink according to the present invention can be used in organic optical devices or electronic devices such as OECTs, thermoelectric devices, tri-value logic inverters, OPVs, OLEDs, organic supercapacitors, batteries, fuel cells, sensors, and memories. [Brief explanation of the drawing]

[0038] Hereinafter, embodiments of the present invention will be described as examples with reference to the attached drawings.

[0039] [Figure 1] This figure shows the steps of the method according to the first embodiment of the present invention. [Figure 2] This figure shows 2D transmission wax patterns of TMQ(a) and OVE(b), 1D line cuts of TMQ(c) and OVE(d), and photographs of TMQ(e) and OVE(f). [Figure 3] This figure shows photographs of TMQH(a) and VE(b). [Figure 4-1] The figures show the electrical properties: (a) PBFDO(OVE) conductivity optimized based on different OVE equivalents and the same monomer concentration of 15 mg mL-1, and (b) PBFDO(OVE) conductivity optimized based on different monomer concentrations and the same OVE equivalent of 1.5 equivalents. [Figure 4-2] The figures show the electrical properties: (c) the electrical conductivity of PBFDO(TMQ) and PBFDO(OVE) under different post-treatment methods, (d) the normalized and time-function values ​​of the conductivity of PBFDO(OVE) polymerized thin films stored at room temperature, and (e, f) the Seebeck coefficient measurements of dialyzed PBFDO(TMQ) and dialyzed PBFDO(OVE). [Figure 5] The figures show thermogravimetric analysis (TGA) results: (a) TGA of dialysis PBFDO (TMQ), (b) TGA of dialysis PBFDO (OVE), (c) TGA of TMQ, (d) TGA of OVE, (e) TGA of PBFDO (TMQ), and (f) TGA of PBFDO (OVE). [Figure 6]This figure shows the differential scanning calorimetry (DSC) curve of a polymer under a nitrogen stream at a heating / cooling rate of 10 / 10°C min-1. [Figure 7] This figure shows the measurement of the Seebeck coefficients for PBFDO(TMQ) and PBFDO(OVE). [Figure 8-1] The figures show spectroscopic confirmation: (a) FTIR spectra of dialyzed PBFDO (TMQ), dialyzed PBFDO (OVE), and non-dialyzed PBFDO (OVE); (b) UV-vis spectra of dialyzed PBFDO (TMQ), dialyzed PBFDO (OVE), and non-dialyzed PBFDO (OVE). [Figure 8-2] The figures show spectroscopic confirmation: (c, e) XPS spectrum of dialysis PBFDO (TMQ), (d, f) XPS spectrum of dialysis PBFDO (OVE). [Figure 8-3] The figures show spectroscopic confirmation: (c, e) XPS spectrum of dialysis PBFDO (TMQ), (d, f) XPS spectrum of dialysis PBFDO (OVE). [Figure 9] The figures show the FTIR spectra: (a) FTIR spectra of PBFDO with and without TMQ, showing the absence of TMQ / TMQH after dialysis with PBFDO; (b) FTIR spectra of PBFDO with and without OVE, showing the absence of OVE / VE after dialysis with PBFDO. [Figure 10-1] This figure shows the 2D GIWAXS pattern of a thin film containing as-polymerized PBFDO(TMQ)(a), dialysis-treated PBFDO(TMQ)(b), as-polymerized PBFDO(OVE)(c), and dialysis-treated PBFDO(OVE)(d). [Figure 10-2] (e) This figure shows the corresponding 1D line cuts in the out-of-plane direction and (f) in-plane direction. [Figure 10-3]This figure shows atomic force microscope (AFM) height images of thin films containing PBFDO(TMQ)(g) in the as-polymerized state, PBFDO(TMQ)(h) after dialysis, PBFDO(TMQ)(i) in the as-polymerized state, and PBFDO(OVE)(j) after dialysis. [Figure 11-1] This figure shows the GIWAXS analysis. [Figure 11-2] This figure shows the GIWAXS analysis. [Figure 11-3] This figure shows the GIWAXS analysis. [Figure 11-4] This figure shows the GIWAXS analysis. [Figure 12] This figure shows the GIWAXS analysis. [Figure 13] This diagram shows a schematic and photographic representation of scale-up production. [Modes for carrying out the invention]

[0040] As described above, the present invention is a method for producing an ink comprising an n-type conductive polymer, a) A step of preparing a catalyst or catalyst precursor, b) A step of obtaining the catalyst by oxidizing the catalyst precursor with an oxidation accelerator, c) A step of adding a monomer to a solvent system containing a polar aprotic solvent in the presence of the above catalyst to obtain a reaction solution, d) A step of polymerizing the above monomer in the above reaction solution to obtain an ink containing an n-type conductive polymer, It includes, The present invention relates to a method wherein the catalyst is a quinone comprising at least one branched side chain comprising at least one chiral center.

[0041] An exemplary embodiment describes a method for polymerizing 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (HBFDO) in DMSO using the catalyst 2-(3-hydroxy-3,7,11,15-tetramethylhexadecyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione (OVE).

[0042] Tetramethyl-1,4-benzoquinone (TMQ) was purchased from Tokyo Chemical Industry Co., Ltd. (TCI). 1,4-benzoquinone (BQ), ethyl cyanoethyl acetate, anhydrous ethanol, 28% aqueous ammonia, 37% hydrochloric acid, activated carbon, toluene, acetic anhydride, chloroform, rac-α-tocopherol (VE), diethyl ether, iron(III) chloride hexahydrate, and methanol were purchased from Sigma-Aldrich and used without further purification.

[0043] synthesis Synthesis of HBFDO 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (HBFDO) was synthesized according to the reported procedure. Briefly, two dropping funnels were attached to a three-necked flask A. Three-necked flask A was placed in circulating water at a constant temperature. To flask A, ethyl cyanoethyl (21.26 g, 20 mL, 187.94 mmol), ethanol (66 mL), and concentrated ammonium hydroxide (15.01 g, 16.66 mL, 431.35 mmol) were added. Meanwhile, benzoquinone (36 g, 333.04 mmol) and ethanol (266 mL) were added to round-bottom flask B and stirred at 40°C for 30 minutes. Then, ethyl cyanoethyl (37.51 g, 35.29 mL, 331.61 mmol) was added to flask B and, while still hot, transferred from flask B to one of the dropping funnels of three-neck flask A. Concentrated ammonium hydroxide (60.32 g, 66.6 mL, 1724.37 mmol) was diluted with 100 mL of water and poured into the other dropping funnel. Both dropping funnels were opened simultaneously, and the dropping rate was adjusted so that the entire ammonia solution was added when 10% of the benzoquinone solution remained. The total dropping time was approximately 30 minutes. The resulting reddish-purple precipitate was stirred for a further 1 hour. The solid was then collected by suction filtration, washed with a large amount of ethanol, and dried to obtain compound 1 (22.13 g, yield 20%) as a dark purple solid.

[0044] In the next step (hydrolysis), compound 1 (25 g, 75 mmol), concentrated hydrochloric acid (172.5 g, 145 mL, 1750 mmol), and water (130 mL) were added to a round-bottom flask and refluxed overnight at 110°C. Water (125 mL) and activated carbon (5 g) were added to the hot reaction mixture, and it was boiled for a further 5 minutes. The activated carbon was removed by filtering through a funnel, and the mixture was washed with a small amount of hot water. The filtrate was cooled to obtain white crystalline solid 2 (12.25 g, yield 72%).

[0045] In the final step, crystalline solid 2 (16 g, 70.74 mmol) was dissolved in anhydrous toluene (800 mL), and anhydrous acetic acid (172.8 g, 160 mL, 1690 mmol) was added. The mixture was stirred overnight at 100 °C, and the solvent was removed under vacuum. The residue was dispersed in methanol and filtered. Acetonitrile was added to the filtered residue, and the mixture was stirred at 90 °C to completely dissolve the solid residue. The solution was placed in an ice bath to crystallize, and then filtered to obtain white crystalline HBFDO (12.11 g, 90%).

[0046] Synthesis of catalytically oxidized vitamin E (OVE) Tocopherol (10 g) was dissolved in diethyl ether (100 mL) and mixed with iron(III) chloride hexahydrate solution (2 g in 25 mL methanol / water (50 / 50, V / V)). After stirring for 30 minutes, the organic phase was collected and reacted again with iron(III) chloride hexahydrate solution. This procedure was repeated five times, after which the organic phase was washed three times with water and dried over sodium sulfate. The solvent was removed at 40°C using a rotary evaporator, and the final product was obtained as a yellow oily substance (9.4 g, 91%).

[0047] Synthesis of PBFDO 3,7-Dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (HBFDO, 3.18 g, 16.72 mmol) and oxidized vitamin E (11.21 g, 25.08 mmol) were dissolved in 212 mL of DMSO under nitrogen. The resulting mixture was heated to 100°C and stirred for 1 hour until the solids content was approximately 0.5 mg mL. -1 I obtained PBFDO (OVE) ink.

[0048] The synthesis of PBFDO using TMQ was performed according to the procedure described in Tang et el., Nature, 2022 Nov;611(7935):271-277.

[0049] Thin film casting PBFDO(TMQ) and PBFDO(OVE) films are spin-cast onto glass, Si, or Si / SiO2 substrates (1500 rpm, 120 seconds, acceleration 1500 rpm s). -1 Then, 3000 rpm for 10 seconds, acceleration 3000 rpm s -1 ) Then, the film was placed on a hot plate at 40°C to dry.

[0050] Absorption spectrum Films containing PBFDO(TMQ) dialysis ink and PBFDO(OVE) dialysis ink were fabricated on a glass substrate by spin coating. UV-Vis-near-infrared spectra were measured using a Perkin Elmer Lambda 900. All FTIR samples except for VE and OVE were prepared by evaporating the solvent on a hot plate at 70°C to form solid samples, and then measuring them in ATR mode on a PerkinElmer Spectron 3 FT-IR spectrometer. VE and OVE did not need to be prepared as they were used directly in the test.

[0051] XPS spectroscopy The above sample was deposited onto an Au substrate in air by drop casting, and then rapidly transferred to a load-lock chamber of an ultra-high vacuum (UHV) system for the following steps. XPS was performed using a Scienta-200 hemispherical analyzer with a monochromatic Al Kα source with a photon energy of 1486.6 eV. The measurement was 1 × 10⁻⁶. -9 The procedure was performed at a base pressure of less than mbar.

[0052] Grazing incidence wide-angle X-ray scattering (GIWAXS) and AFM characterization The GIWAXS experiment was conducted according to the procedure described above. All samples for GIWAXS measurement were deposited on cut silicon wafers. The above samples were measured at Beamline 9A at the Pohang Accelerator Laboratory in South Korea. The X-ray energy was 11.08 eV and the incident angle was 0.12°. The samples were measured in a vacuum, and the total exposure time was 10 seconds. Scattered X-rays were recorded by a charge-coupled detector placed 220.8498 mm away from the sample. The AFM image was taken with a spring constant of 40 N m. -1 The footage was recorded using a silicon nitride cantilever with a Bruker Icon XR.

[0053] Electrical characteristics evaluation Electrical conductivity was measured using a four-point probe technique with the Keithley 4200-SCS semiconductor characterization system. Conductivity was calculated using the following formula.

number

[0054] As mentioned above, TMQ exhibits high crystallinity (Figures 2c, 2e, and 2g). Chinese Patent No. 115651448 pointed out that when TMQ is used as a catalyst in the synthesis of PBFDO, dialysis is necessary to remove the catalyst and increase conductivity. However, dialysis requires a large amount of DMSO solvent and a long period (2 weeks), making it unsuitable for efficient batch production. Subsequent investigations revealed that numerous quinones possess catalytic activity in PBFDO polymerization.

[0055] The inventors reduced the crystallinity of the catalyst by adding at least one saturated branched side chain. (rac)-α-tocopherol (VE), a hydroquinone characterized by a long alkyl side chain, proved promising. Benzoquinone OVE with an extended alkyl side chain was synthesized via a one-step oxidation process. [ka]

[0056] Surprisingly, OVE exhibited potent catalytic activity in HBFDO polymerization. [ka]

[0057] Because OVE is essentially oily (Figures 2d, 2f, and 2h), dialysis is not required, it can be retained in the product, and highly conductive PBFDO is produced. During the catalytic polymerization of PBFDO with TMQ and OVE, a portion of the catalyst is oxidized to TMQH and VE, respectively (Figure 3).

[0058] The electrical and thermoelectric properties of PBFDO synthesized using different catalysts were investigated and compared. The electrical conductivity of films made with non-dialysis PBFDO (TMQ) ink and dialysis PBFDO (TMQ) ink differed significantly (509 S cm, respectively). -1 and 1332S cm -1 However, the electrical conductivity of non-dialysis PBFDO(OVE) film and dialysis PBFDO(OVE) film is similar (1320 S cm, respectively). -1 and 1340S cm -1(Figure 4c). This shows that PBFDO(OVE) can provide good electrical properties even without dialysis. In contrast, the electrical properties of non-dialysis PBFDO(TMQ) make it unsuitable for direct use as a conductive ink. PBFDO(OVE) exhibits excellent stability, maintaining 97% of its initial conductivity even after 180 days of exposure to air (Figure 4d). Furthermore, PBFDO(OVE) shows good thermal stability (Figure 5), and the curve in Figure 6 did not show any obvious exothermic or endothermic behavior in the range of 25°C to 250°C, indicating that no phase transition was observed. The Seebeck coefficient of PBFDO(OVE) after dialysis is -30.91±0.65 μV K -1 This was measured (Figure 4e). The Seebeck coefficient for dialysis PBFDO (TMQ) was -26.78 ± 0.59 μV K -1 These measurements show lower values ​​compared to dialysis PBFDO(OVE). Negative values ​​indicate the n-type properties of these polymers.

[0059] Furthermore, the Seebeck coefficient for non-dialysis PBFDO (TMQ) decreased by 22% compared to the dialysis version, while the Seebeck coefficient for non-dialysis PBFDO (OVE) remained essentially unchanged compared to the dialysis version (Figure 7). Negative values ​​indicate the n-type properties of these polymers.

[0060] The chemical structure of PBFDO(OVE) was analyzed and compared with that of dialysis-treated PBFDO(TMQ). The FTIR spectrum of PBFDO(OVE) revealed several distinctive features in contrast to that of dialysis-treated PBFDO(TMQ) (Figure 8a). In dialysis-treated PBFDO(TMQ), the 1781 cm⁻¹ spectrum was observed. -1 A prominent peak corresponding to the C=O stretching of the lactone group and 1277 cm -1 A discernible CO signal was revealed for . In contrast, PBFDO(OVE) did not have a clear peak in the same region. Furthermore, PBFDO(OVE) showed a peak corresponding to the alkyl chain of OVE at 2850 cm². -1 ~2975cm -1 A significant alkane CH signal was observed during this period. However, after dialysis, PBFDO(OVE) was 3000 cm³.-1 ~1000cm -1 The signal between these points is consistent with that of dialyzed PBFDO(TMQ), partially demonstrating that PBFDO is indeed produced by OVE catalytic polymerization. Furthermore, PBFDO(TMQ) without dialyzing was characterized along with the two catalysts TMQ and OVE, as well as the corresponding reduction products TMQH and VE produced during the catalytic reaction (Figure 9). These also exhibit similar characteristics in the UV-Vis spectra between 350 nm and 2000 nm (Figure 8b). To further verify that OVE catalytic polymerization produces the same PBFDO polymer as TMQ catalytic polymerization, the chemical structure of dialyzed PBFDO(OVE) was analyzed using X-ray photoelectron spectroscopy (XPS). In the C(1S) spectrum of dialyzed PBFDO(TMQ), CC / C=C appears at 285.1 eV, CO at 286.6 eV, and C=O at 289.1 eV (Figures 8c, 8d). Dialyzed PBFDO(OVE) showed perfectly consistent binding energies for each peak. Similarly, in the O(1S) spectrum of dialysis PBFDO(TMQ), C=O is 531.4 eV, COC is 533.2 eV, and C=OH + It appears at 535.1 eV (Figures 8e and 8f). Dialysis PBFDO (OVE) also showed a perfectly consistent binding energy for each peak.

[0061] Based on the analysis of the above FTIR, UV-Vis, XPS data, and elemental analysis data (Table 1), it has been proposed that the chemical structures of PBFDO synthesized by OVE catalytic action and TMQ catalytic synthesis are identical. [Table 1]

[0062] The microstructure of PBFDO thin films was investigated using grazing incidence wide-angle X-ray scattering (GIWAXS) and atomic force microscopy (AFM) (Figures 10a to 10j). GIWAXS analysis (Figures 10a to 10f) revealed that the PBFDO chains are mainly oriented toward the edges of the substrate. All four types of PBFDO, namely PBFDO (TMQ) (a) in the as-polymerized state, PBFDO (TMQ) (b) after dialysis, PBFDO (OVE) (c) in the as-polymerized state, and PBFDO (OVE) (d) after dialysis, were q xy = 1.85 Å -1 A strong π-π stacking (010) peak is observed near (d interval = 3.40 Å) (Figures 11e to 11h). However, PBFDO(TMQ)(a) in the polymerized state and PBFDO(TMQ)(b) after dialysis show a lamellar packing distance d interval = 10.83 Å[q z = 0.58 Å -1 The (100) peak is shown at this point, which represents the d interval = 11.42 Å between PBFDO(OVE)(c) in the polymerized state and PBFDO(OVE)(d) after dialysis. -1 [q zThis is similar to the (100) peak at =0.55 Å (Figures 11a-11d). Clearly, the as-polymerized PBFDO(TMQ) also has strong π-π stacking (010) impurity peaks and lamellar (100) impurity peaks. This indicates that highly crystallized TMQ remains in the PBFDO. Furthermore, as shown in Figure 12, in π-π stacking (010) diffraction, the as-polymerized PBFDO(OVE) has a shorter coherence length (20.3 Å for as-polymerized PBFDO(OVE) versus 23.4 Å for dialysis-treated PBFDO(TMQ)) and greater quasicrystalline disorder (0.154 for as-polymerized PBFDO(OVE) versus 0.143 for dialysis-treated PBFDO(TMQ)). AFM analysis revealed that the dialysis-treated PBFDO(TMQ)(h) film, the as-polymerized PBFDO(OVE)(i) film, and the dialysis-treated PBFDO(OVE)(j) film all possessed a flat polycrystalline morphology (Figures 10h to 10j). In contrast, the as-polymerized PBFDO(TMQ)(g) exhibited significant surface roughness and clear aggregate formation.

[0063] In summary, the present invention discloses a simple method for synthesizing conductive polymers using, for example, oxidized vitamin E (OVE) as a catalyst. This process includes a simple oxidation step of converting vitamin E to its oxidized form. The resulting polymer PBFDO exhibits excellent electrical conductivity, with an average conductivity of 1320 S cm. -1 The maximum conductivity is 1800 S cm. -1 Furthermore, the spin-coated film exhibited excellent air stability, maintaining 97% conductivity even after 180 days in the atmosphere. To demonstrate the ease of using OVE as a catalyst for PBFDO polymerization, production was scaled up using a 20L reactor to produce 10L of PBFDO ink (Figure 13).

[0064] While the present invention has been described with reference to various embodiments, those skilled in the art will understand that modifications are possible without departing from the scope of the invention. The detailed description is to be considered illustrative, and the appended claims, including all equivalents, are intended to define the scope of the invention.

Claims

1. A method for producing an ink comprising an n-type conductive polymer, a) A step of preparing a catalyst or catalyst precursor, b) A step of obtaining the catalyst by oxidizing the catalyst precursor with an oxidation accelerator, c) A step of adding a monomer to a solvent system comprising a polar aprotic solvent in the presence of the catalyst to obtain a reaction solution, d) A step of polymerizing the monomer in the reaction solution to obtain an ink containing an n-type conductive polymer, It includes, A method wherein the catalyst is a quinone comprising at least one branched side chain comprising at least one chiral center.

2. The method according to claim 1, wherein the at least one branched side chain is a saturated branched side chain.

3. The method according to claim 1 or 2, wherein the catalyst is vitamin E.

4. The method according to claim 3, wherein the vitamin E is selected from the group consisting of α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, α-tocotrienol, β-tocotrienol, γ-tocotrienol, δ-tocotrienol, and mixtures thereof.

5. The method according to any one of claims 1 to 4, wherein the polar aprotic solvent is DMSO and the oxidation accelerator is hydrogen bromide (HBr).

6. The oxidation promoter is an ionic liquid comprising cations and anions, and the method is a') Step of electrolyzing the reaction solution. It further includes, The method according to any one of claims 1 to 4, wherein step a') is performed simultaneously with or after step a).

7. The method according to claim 6, wherein step a') is performed using a nickel cathode and a carbon anode for a period of 10 to 60 minutes at a voltage in the range of 4 to 6 V.

8. The method according to claim 6 or 7, wherein the cation in the ionic liquid is selected from the group consisting of 1-ethyl-3-methylimidazolium (EMIM), 1-butyl-3-methylimidazolium (BMIM), 1-allyl-3-methylimidazolium (AMIM), 1-hexyl-3-methylimidazolium (HMIM), butylmethylpyrrolidinium (BMP), propylmethylpyrrolidinium (PMP), triethylsulfonium, and mixtures thereof.

9. The anion is chloride (Cl － ), bromide (Br － ), iodide (I － ), acetate (OAc), tetrafluoroboric acid (BF ４ － ), hexafluorophosphate (PF ６ － ), bistrifluoromethanesulfonimide (TFSI), trifluoromethanesulfonic acid (OTf), dicyanamide (DCA), hydrogen sulfate (HSO ４ － ), ethyl sulfate (ESO ４ － ), thiocyanate (SCN), tosylate (OTs), mesylate (OMs), tetrachloroaluminate (AlCl ４ － ), diethyl phosphate (DEP), dimethyl phosphate (DMP), lactate (La), L-alanine anion (APP), and a mixture thereof, and the method according to any one of claims 6 to 8.

10. The method according to any one of claims 1 to 9, wherein the polar aprotic solvent is dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMA), or a combination thereof.

11. The method according to any one of claims 1 to 10, wherein the ratio of the oxidation accelerator to the catalyst is in the range of 0.1 to 100, preferably 0.25 to 5, and more preferably 1 to 3.

12. The method according to any one of claims 1 to 11, wherein step b) is performed at a temperature of 20°C to 150°C.

13. The method according to any one of claims 1 to 12, wherein the monomer is 3,7-dihydrobenzo[1,2-b:4,5-b]difuran-2,6-dione (HBFDO) and the n-type conductive polymer is poly(benzodifraione) (PBFDO).

14. The method described above is c) A step of removing the catalyst by extraction and recycling the catalyst. The method according to any one of claims 1 to 13, further comprising:

15. An ink comprising an n-type conductive polymer manufactured by the method described in any one of claims 1 to 14.

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