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 obtaining a reaction solution by adding a monomer to a solvent system comprising a polar aprotic solvent and an oxidizing agent in the presence of a catalyst, b) 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 or a quinone precursor, and the catalyst comprises at least one branched side chain.

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 polymer inks have a wide range of industrial applications, including antistatic coatings, polymer capacitors, organic solar cells, displays (LCD / OLED), and printed electronics. Currently, PEDOT:PSS is the most advanced p-type (hole transport) conductive polymer ink on the market. PEDOT:PSS is produced by a simple casting method, yielding 1S cm -1 It exhibits high electrical conductivity exceeding 4000 S cm by secondary doping or post-treatment. -1 It reaches values ​​exceeding [a certain threshold]. However, n-type (electron transport) conductive polymers become important when considering complementary components for semiconductor devices and circuits.

[0003] Recently, Fei Huang et al. published a paper titled "2000s cm" -1 We reported a method for producing solution-treated n-type conductive polymer poly(benzodiflaione) (PBFDO) having an electrical conductivity exceeding 1 / 2 (Nature, 2022, s41586-022-05295-8). To initiate the polymerization reaction, duroquinone (TMQ) must be added as a catalyst. TMQ is not environmentally friendly and is not a renewable resource. Furthermore, TMQ is highly crystalline and prone to crystallization, affecting film formation during printing. Therefore, PBFDO inks require dialysis to remove TMQ, and since ink dilution is unavoidable during the dialysis process, solvent removal is necessary afterward.

[0004] 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]

[0005] 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 obtaining a reaction solution by adding a monomer to a solvent system comprising a polar aprotic solvent and an oxidizing agent in the presence of a catalyst, b) 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.

[0006] The catalyst described above is a quinone or quinone precursor comprising at least one branched side chain. The term "quinone precursor" indicates that it is 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. Furthermore, the side chain may comprise at least one chiral center. The catalyst according to the present invention has been demonstrated not to crystallize during polymerization reactions because at least one branched side chain prevents such crystallization. Since the catalyst does not crystallize, the dialysis step is eliminated.

[0007] 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, thus eliminating the need for a dialysis step to remove the catalyst.

[0008] 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]

[0009] Furthermore, the monomer may be in the form of a heterocyclic moiety having at least one, preferably at least two, rings, preferably a 5-membered ring, fused to a centrally symmetric benzene ring. The monomer further comprises an active hydrogen and at least one electron-withdrawing group at the benzyl 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. [ka]

[0010] In particular, the monomer is 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (HBFDO). In such embodiments, the n-type conductive polymer is polybenzodifraione (PBFDO).

[0011] According to certain embodiments, the catalyst may be vitamin E. As is well known in the art, vitamin E is a group of eight lipid-soluble compounds comprising four tocopherols and four tocotrienols, as shown below. [ka]

[0012] 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, 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.

[0013] 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 catalyst. Compared to the three-step method reported by Fei Huang, the method of the present invention achieves a significant simplification.

[0014] Surprisingly, it was found that while vitamin E itself does not have catalytic activity, its oxidized form does. In the presence of an oxidizing agent, vitamin E forms a benzoquinone derivative. According to the present invention, in-situ oxidation initiates the polymerization reaction. Therefore, the method of the present invention offers the advantage of being a simplified and cost-effective method for producing an ink containing an n-type conductive polymer compared to methods known in the art. The major advantages of using vitamin E as a catalyst are its availability, low cost, and non-toxicity.

[0015] In certain embodiments, the polar aprotic solvent is DMSO, and the oxidizing agent is hydrogen bromide (HBr). HBr is volatile and does not affect film formation when the ink is printed.

[0016] Alternatively, the oxidizing agent is an ionic liquid comprising cations and anions. In such embodiments, the method is a') Step of electrolyzing the above reaction solution. It further includes, Process a') is performed simultaneously with or after process a).

[0017] In particular, step a') can be carried out at a voltage within the range of 4 to 6 V for a period within the range of 10 to 60 minutes using a nickel cathode and a carbon anode.

[0018] The cation in the 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.

Chemical formula

[0019] According to the present invention, the anion can be selected from the group consisting of chloride (Cl - ), bromide (Br - ), iodide (I - ), acetate (OAc), tetrafluoroborate (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 structure of the above anion is shown below.

Chemical formula

[0020] As described above, the solvent system according to the method of the present invention comprises a polar aprotic solvent. The polar aprotic solvent may be dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMA), or a combination thereof.

[0021] The ratio of the above-mentioned oxidizing agent to the above-mentioned vitamin E is in the range of 0.1 to 100, preferably 0.25 to 5, and more preferably 1 to 3.

[0022] The polymerization reaction, i.e., step b) of the method of the present invention, can occur at temperatures between 20°C and 150°C.

[0023] In order to further improve the cost efficiency of the method according to the present invention, the method according to the present invention is c) A process of removing the catalyst by extraction and recycling the catalyst. It may further include the following.

[0024] Extraction can be carried out using alkanes or ethers.

[0025] The overall outline of the method of the present invention can be summarized as follows: [ka]

[0026] The present invention further relates to an ink comprising an n-type conductive polymer, manufactured by the above method.

[0027] Therefore, the above-mentioned 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 may exhibit an electrical conductivity of at least 10 S / cm, preferably at least 1000 S / cm, and more preferably at least 5000 S / cm.

[0028] 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]

[0029] Hereinafter, embodiments of the present invention will be described as examples with reference to the attached drawings.

[0030] [Figure 1] This figure shows the steps of the method according to the first embodiment of the present invention. [Figure 2] This figure shows the steps of the method according to the second embodiment of the present invention. [Figure 3] Figure 3a shows the electrical conductivity of PBFDO inks catalyzed with different vitamin E equivalents without a dialysis process. Figure 3b shows a comparison of the electrical conductivity of PBFDO inks catalyzed with TMQ and vitamin E, respectively. [Figure 4] Figures 4a–4d show a comparison of GIWAXS data for TMQ and vitamin E-catalyzed PBFDO inks with and without a dialysis process. [Modes for carrying out the invention]

[0031] As described above, the present invention is a method for producing an ink comprising an n-type conductive polymer, a) A step of obtaining a reaction solution by adding a monomer to a solvent system comprising a polar aprotic solvent and an oxidizing agent in the presence of vitamin E, b) 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 or a quinone precursor, and the catalyst comprises at least one branched side chain.

[0032] The highly conductive PBFDO ink was synthesized using a vitamin E catalyst. Vitamin E can be readily converted in situ to its oxidation intermediate by adding 2 equivalents (relative to vitamin E) of concentrated HBr (commercially available 48% aqueous solution) to its DMSO solution.

[0033] Vitamin E can be readily converted in situ to its oxidized intermediate by electrolysis in DMSO solution using 2 equivalents of ionic liquid electrolyte (relative to vitamin E), a nickel cathode, and a carbon anode, at an electrolytic voltage of 4-6V for 10-60 minutes.

[0034] After obtaining a catalyst containing vitamin E as described above, HBFDO (5-15 mg / mL) was added to a DMSO solution of oxidized vitamin E, and polymerization was carried out by heating to 100°C. After cooling to room temperature, PBFDO ink was obtained without any post-treatment. As shown in Figure 3a, a high conductivity of 1000 S / cm was achieved.

[0035] Furthermore, it was confirmed that vitamin E, HBr, or ionic liquids do not need to be removed from the ink and have little effect on the film formation or conductivity of those inks (Figure 3b). TMQ significantly affects the film formation and conductivity of the ink and therefore must be removed from the ink (Figure 3b).

[0036] It was demonstrated that vitamin E does not affect the final microstructure of the coated PBFDO film, regardless of whether a dialysis process is used (Figures 4a, 4b). On the other hand, it was confirmed that TMQ must be removed from the ink by dialysis to prevent the formation of TMQ crystals, which affect the microstructure and conductivity of the final film (Figures 4c, 4d). Therefore, the method of the present invention eliminates the need for a dialysis step, improving efficiency and reducing the time burden.

[0037] In summary, a one-pot method was developed for the synthesis of highly conductive n-type polymer inks using vitamin E as a catalyst. This method requires no post-processing. A high conductivity of 1000 S / cm was measured.

[0038] 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 obtaining a reaction solution by adding a monomer to a solvent system comprising a polar aprotic solvent and an oxidizing agent in the presence of a catalyst, b) 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 or a quinone precursor, and the catalyst comprises at least one branched side chain.

2. The method according to claim 1, wherein the at least one branched chain comprises at least one chiral center.

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 oxidizing agent is hydrogen bromide (HBr).

6. The oxidizing agent 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 oxidizing agent 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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