A method for synthesizing n-type conductive conjugated polymers and screening catalysts

Abstract

This invention discloses a method for synthesizing n-type conductive conjugated polymers and screening catalysts, belonging to the technical field of conductive polymer material synthesis. By studying the redox potentials of various metal compounds, this invention proposes a method for screening catalysts for the synthesis of n-type conductive conjugated polymers. By introducing trace amounts of inexpensive metal compounds as catalysts, n-type conductive conjugated polymers, such as poly(benzofurandione) (PBFDO), can be efficiently synthesized. This method not only overcomes the problem of large catalyst residues in conventional synthesis methods but also simplifies the operation. The resulting PBFDO exhibits a conductivity exceeding 0.05, addressing the low conductivity of most n-type organic conductive polymers and achieving high-performance conductivity comparable to p-type materials. It is widely applicable to various organic functional materials and organic electronic devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of conductive polymer synthesis, and in particular relates to a method for efficiently synthesizing n-type conductive polymers such as poly(benzofurandione) (PBFDO) and a method for screening the catalysts used, as well as applications in the field of organic functional materials and organic electronics. Background Art

[0002] Metal compounds have been widely used as catalysts in organic chemistry reactions, the most representative of which is the Suzuki coupling reaction, recognized by the 2010 Nobel Prize in Chemistry. In this reaction, zero-valent palladium, in the presence of a ligand, catalyzes the cross-coupling of aryl or alkenyl boronic acids / boronic esters with chlorine, bromine, or iodine-substituted aromatic hydrocarbons or alkenes, thereby enabling the construction of diverse molecular frameworks and providing an important path for the development of organic synthesis methodology.

[0003] Recently, Huang et al. synthesized for the first time an n-type conducting polymer, poly(benzofurandione) (PBFDO), with a conductivity as high as The synthesis of this polymer uses duroquinone as an oxidant to undergo oxidative polymerization with 3, 7-dihydrobenzo[1, 2-b:4, 5-b′]difuran-2, 6-dione (HBFDO). In situ reduction doping is achieved during the reaction, significantly improving the doping efficiency. The resulting product has excellent stability and good solution processability (Nature 2022, 611, 271-277). As an n-type highly conductive polymer material without solubilizing side chains, PBFDO not only has high conductivity but also good optical transparency. Its discovery is considered a major breakthrough in the field of organic semiconductors.

[0004] The fundamental reason for this breakthrough is that organic conducting polymers, with their unique conjugated structure, excellent solution processability, and flexibility, have become the core of a new generation of organic functional materials and organic electronics research. Conjugated polymers, through their delocalized π-electron system, endow materials with unique optical, electrical, and magnetic properties, and are widely used in fields such as organic solar cells (OPVs), organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), organic thermoelectric devices (OTEs), and organic electrochemical transistors (OECTs). However, the construction of high-performance devices relies on the synergistic operation of p-type and n-type semiconductor materials. Compared with the intensively researched, rapidly developing, and widely used p-type materials (hole transport materials), the development of n-type materials (electron transport materials) has long lagged behind, mainly due to their low mobility, poor doping efficiency, insufficient stability, and a lack of systematic research on structure-performance relationships. These factors have become one of the key factors restricting the further improvement of the performance of organic electronic devices.

[0005] With the advent of the highly conductive n-type polymer PBFDO, research on its synthesis, structure regulation, and performance optimization has rapidly expanded, becoming a hot topic in this field. Compared to traditional PBFDO synthesis methods that require reactions in an inert atmosphere, Mei et al. developed a novel method in 2023 for synthesizing PBFDO via a cascade reaction in air using soluble copper acetate as a catalyst (J. Am. Chem. Soc. 2023, 145, 3706-3715). While this method reduces the requirements for the reaction atmosphere, similar to existing synthesis methods (such as CN 115490835 A and CN 119569998 A), it still requires the addition of a large amount of catalyst, increasing reaction costs. It also introduces a complex dialysis step, which is not only time-consuming and labor-intensive, but also consumes large amounts of organic solvents, significantly increasing process costs and technical barriers.

[0006] To further simplify the synthesis process, Yang et al. used α-trocoquinone (α-TQ) as a catalyst to synthesize PBFDO, which effectively avoided the dialysis step and provided the possibility for large-scale production. The conductivity of the obtained polymer can reach (Adv. Mater. 2025, 2502426. https: / / doi.org / 10.1002 / adma.202502426). However, this method still has problems such as the large amount of catalyst required, the need to operate in a nitrogen atmosphere, and the high amount of residual α-TQ and its reduction product (α-TOH), which limit its further application in high-purity electronic devices.

[0007] In addition, Mei et al. also reported a method using A method for preparing PBFDO by catalyzing the Riley oxidation and aldol condensation reaction of HBFDO. By controlling the solvent system, temperature, time, and material ratio, the conductivity can be as high as (Angew. Chem. Int. Ed. 2025, 64, e202418668). Although this method does not require dialysis, the reaction still needs to be carried out in an inert atmosphere and a large amount of The catalyst produces a high content of elemental Se in the reaction solution, which requires the post-processing process to rely on filtration and repeated centrifugation operations, increasing the complexity of the operation and being unfavorable for large-scale continuous production.

[0008] Therefore, how to rationally screen efficient catalysts and develop a synthesis process for n-type highly conductive conjugated polymers with low cost, low residue, simple post-processing process and excellent solution processability is a key technical problem that needs to be solved urgently to achieve large-scale application of organic electronic devices. Summary of the Invention

[0009] In order to overcome the shortcomings and deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a method for efficiently synthesizing n-type conductive conjugated polymers such as poly (benzofurandione) (PBFDO), which successfully synthesizes a conductive conjugated polymer with an electrical conductivity exceeding 100 nm by introducing a trace amount of inexpensive metal compound as a catalyst. PBFDO makes up for the low conductivity of most n-type organic conductive polymers and can achieve high-performance conductivity matching that of p-type, providing a new synthesis method and idea for the development of this material.

[0010] To achieve the above technical objectives, the present invention first studies the redox potentials of various metal compounds themselves and provides a method and criteria for screening catalysts in the synthesis step of n-type conductive conjugated polymers.

[0011] The n-type conductive conjugated polymers prepared by the efficient synthesis method of the present invention, such as poly(benzofurandione) (PBFDO), have excellent electrical conductivity and can be widely used in organic functional materials and organic electronics such as carbon nanotube purification, wet spinning, wet thin films, conductive fibers, organic light-emitting diodes, organic field-effect transistors, organic electrochemical transistors, organic thermoelectrics, organic solar cells, and electromagnetic shielding.

[0012] The n-type conductive conjugated polymer of the present invention is a homopolymer or a copolymer, comprising one or more polymeric units, wherein the polymeric units are derived from a monomer having a structure represented by formula (I):

[0013]

[0014] Formula (I)

[0015] Among them, Ar 1 It is a condensed-ring aromatic structure, such as benzene, naphthalene, anthracene, thiophene, dithiophene, pyrrole, dipyrrole, furan, difuran, selenophene, diselenophene, tellurophene, ditellurophene, benzodithiophene, benzodifuran, benzodipyrrole, benzodiselenophene, terthiophene, etc., and contains different condensed-ring aromatic structures. R1 represents Ar 1 The one or more same or different substituents are selected from hydrogen atom, halogen (F, Cl, Br, I), cyano, nitro, alkyl, halogen-substituted alkyl, alkenyl, alkynyl or silicon-protected ethynyl, etc.; X and Y are the same or different and are each independently O, S, Se, Te or N-R2, wherein R2 is selected from hydrogen atom, alkyl, cycloalkyl, halogen-substituted alkyl and halogen-substituted cycloalkyl.

[0016] Furthermore, when R1 is an alkyl group, it is preferably a C1-C12 alkyl group, more preferably a C1-C6 alkyl group, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, etc.; when R1 is a halogen-substituted alkyl group, it is preferably a halogen-substituted C1-C4 alkyl group, such as trifluoromethyl; when R1 is an alkenyl group, it is preferably a C3-C12 alkenyl group, more preferably a C3-C6 alkenyl group, such as allyl, etc.; when R1 is an alkynyl group, it is preferably a C2-C6 alkynyl group, such as ethynyl, propynyl, etc.; when R1 is a silicon-protected ethynyl group, it is preferably an alkylsilicon-protected ethynyl group, such as triisopropylsilylethynyl, triisobutylsilylethynyl, etc.

[0017] Preferably, X and Y are O, S or N-R2.

[0018] Preferably, R2 is a hydrogen atom, a C1-C4 alkyl group, a halogen-substituted C1-C4 alkyl group, a C5-C7 cycloalkyl group, or a halogen-substituted C5-C7 cycloalkyl group.

[0019] Several specific examples of compounds of formula (I) are given below.

[0020] When X and Y are oxygen atoms, Ar 1 When it is a benzene ring and there is no substituent R1, the compound of formula (I) is 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (abbreviated as benzodifurandione, HBFDO), and its specific structure is as follows:

[0021]

[0022] When X and Y are oxygen atoms, Ar 1 When it is a naphthalene ring and there is no substituent R1, the specific structure of the compound of formula (I) includes the following three types (different ring-joining sites in the condensed ring aromatic structure):

[0023]

[0024] When X and Y are sulfur atoms, and Ar 1 is a benzene ring and there is no substituent R1, the specific structure of the compound of formula (I) is as follows:

[0025]

[0026] When X and Y are N-R2, and Ar 1 is a benzene ring, and there is no substituent R1 on Ar 1 the specific structure of the compound of formula (I) is as follows:

[0027]

[0028] The n-type conductive conjugated polymer of the present invention has a specific structure composed of formula (I) and formula (I). In this composed structure, the structural units of formula (I) and formula (I) can be the same or different, and can contain one or more structural units in formula (I). The neutral state (such as BFDO) and doped state (such as PBFDO) of the n-type conductive conjugated polymer are the structures of formula (II) and formula (III) respectively:

[0029]

[0030] Formula (II) Formula (III)

[0031] In formula (II) and formula (III), n is a positive integer representing the degree of polymerization; m is a positive integer with a value lower than n, representing the degree of reduction doping; Ar 1 , R1, X, and Y are the same or different.

[0032] The method for efficiently synthesizing the above n-type conductive conjugated polymer provided by the present invention is to disperse one or more monomers shown in formula (I) and a metal compound in an organic solvent under an air atmosphere, and then heat the reaction to obtain the n-type conductive conjugated polymer. Among them, the metal compound serves as a catalyst and is insoluble in the organic solvent, and under the reaction conditions, the redox potential of the metal compound satisfies the following relationship: E(neutral state of n-type conductive conjugated polymer / polymerization monomer) < E(high-valent metal compound / low-valent metal compound) < E(O2 / H2O).

[0033] In the method for efficiently synthesizing the n-type conductive conjugated polymer provided by the present invention, the amount of the metal compound used is 1 ppm to 0.01 times the monomer equivalent.

[0034] The metal compound being poorly soluble in the organic solvent means that the metal compound is always insoluble or slightly soluble in the solvent of the reaction system no matter it is in a high-valent state or a low-valent state.

[0035] Taking poly(benzofurandione) (PBFDO) as an example, its synthesis method includes the following steps:

[0036] In an air atmosphere, benzofurandione (HBFDO) and a metal compound are dispersed in an organic solvent and then heated to react. After the reaction is completed, an n-type conductive conjugated polymer PBFDO can be obtained.

[0037] according to Figure 1 The polymerization reaction mechanism of the n-type conducting polymer PBFDO indicates that the metal compound can be oxidized to a high-valent state by oxygen and reduced to a low-valent state by HBFDO. Therefore, the redox potential of the metal compound must satisfy the following relationship: E(BFDO / HBFDO) < E(high-valent metal compound / low-valent metal compound) < E(O2 / H2O). Under standard conditions, their potentials are related as follows: -2.25 V < E°(high-valent metal compound / low-valent metal compound) < 1.23 V, where the standard redox potential E°(BFDO / HBFDO) ≈ -2.25 V and E°(O2 / H2O) = 1.23 V. Based on this relationship, we screened out the following four types of metal compounds:

[0038] (1) Alkaline earth metals

[0039] Table 1

[0040]

[0041] (2) Transition metals

[0042] Table 2

[0043]

[0044] (3) Rare earth metals

[0045] Table 3

[0046]

[0047] (4) Main group metals

[0048] Table 4

[0049]

[0050] Therefore, the metal compounds described in the present invention are compounds of various insoluble forms of the above four types of metal ions, such as one or more of oxides, halides (including fluorides, chlorides, bromides, and iodides), sulfides, salts, bases, acid salts, and the like. These insoluble forms of the above four types of metal ions refer to compounds that are insoluble or slightly soluble in the reaction system solvent during the synthesis of n-type conductive conjugated polymers, regardless of whether they are in a high- or low-valent state. For example, during the catalytic oxidative polymerization of HBFDO to BFDO and its in situ reduction to PBFDO, the metallic element copper is always present in the reaction system as microparticles. This copper not only provides adsorption sites for the chemical substrate but also lowers the reaction barrier, activating the reaction process and promoting atomic or electron transfer between the chemical substrate and the metal particle surface, significantly enhancing the reaction progress. Therefore, only a trace amount of the insoluble metal compound needs to be added to the reaction system to achieve the desired catalytic effect. This is particularly important and is different from the previous report by Mei et al., which required the addition of an ultra-high 1:1 equivalent of soluble copper acetate to achieve the ideal catalytic effect (J. Am. Chem. Soc. 2023, 145, 3706 3715).

[0051] For efficient synthesis of PBFDO, it is preferred that the standard redox potential of the metal ions be in the range of -0.8 V to 0.8 V. For example, the standard redox potentials of cuprous particles and silver ions are E° (Cu + / Cu) = 0.5200 V and E° (Ag + / Ag) = 0.7996 V, both within the above range. Therefore, the use of compounds containing insoluble forms of these two metal ions can achieve good catalytic effects when added in trace amounts. Specific data are shown in Examples 5 and 6.

[0052] The organic solvent is a mixture of one or more of a halogenated hydrocarbon solvent, an alcohol solvent, an ether solvent, an ester solvent, a sulfone solvent, a ketone solvent, and an amide solvent, such as tetrahydrofuran, chloroform, ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, propyl propionate, butyl propionate, toluene, xylene, trimethylbenzene, chlorobenzene, dichlorobenzene, trichlorobenzene, methanol, ethanol, propanol, ethylene glycol, isodimethylformamide, dimethylformamide, dimethyl sulfoxide, dimethylacetamide, acetone, butanone, cyclohexanone, methyl butanone, methyl ether, ethyl ether, propyl ether, pyridine, phenol, N-methylpyrrolidone, etc. Preferably, an aprotic solvent with high polarity is selected, such as dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, etc.

[0053] In the above-mentioned method for efficiently synthesizing n-type conductive conjugated polymers, the temperature of the heating reaction is set between 60 and 150°C, preferably, set to 80°C.

[0054] The n-type conductive conjugated polymer solution produced by the above reaction can be directly used in subsequent processing without additional post-processing. Compared to the tedious post-processing steps typically required in the prior art, such as dialysis, centrifugation, and filtration, this invention significantly simplifies the process by screening highly efficient catalysts, ultimately developing a low-cost, highly conductive n-type conjugated polymer synthesis system with excellent solution processing properties.

[0055] The n-type conjugated polymer synthesized according to the method of the present invention has a wide range of uses in the fields of organic functional materials and organic electronics, including but not limited to: the use of the n-type conjugated polymer in electron transport layers, the use of the n-type conjugated polymer in thermoelectric materials, the use of the n-type conjugated polymer in electromagnetic shielding materials, the use of the n-type conjugated polymer in carbon nanotube purification, the use of the n-type conjugated polymer in wet spinning, the use of the n-type conjugated polymer in wet thin films, the use of the n-type conjugated polymer in conductive fibers, the use of the n-type conjugated polymer in organic field-effect transistors, the use of the n-type conjugated polymer in organic electrochemical transistors, and the use of the n-type conjugated polymer in organic electrochromism, etc.

[0056] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0057] (1) The present invention provides a novel method for synthesizing PBFDO and other n-type conjugated polymers, which can synthesize polymers with excellent electrical conductivity using only a trace amount of catalyst. This solution solves the problem of large amounts of catalyst residue in conventional methods.

[0058] (2) The present invention provides a screening criterion for catalysts in the synthesis step of n-type conductive conjugated polymers, which facilitates the search for catalysts that are low in toxicity, low in cost, widely available, and highly universal. The catalysts selected in the examples can catalyze oxidative polymerization and reductive doping reactions of a variety of different system substrates.

[0059] (3) The synthetic steps of the present invention are simple to operate, and the post-processing is simple and efficient, which is suitable for large-scale production and preparation.

[0060] (4) The polymer synthesized by the present invention has a wide range of applications and has great development potential in the fields of electromagnetic shielding, carbon nanotube purification, wet spinning, wet film formation, conductive fibers, solid-state batteries, electrochemical transistors, electrochromism, etc.

[0061] Table 5. Comparison of various parameters of the synthesis of n-type highly conductive polymer PBFDO in the present invention and reported technologies

[0062] BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 Schematic diagram of the efficient synthesis of n-type conductive conjugated polymer PBFDO according to the present invention, wherein: (a) shows the reaction mechanism of metal compound-catalyzed polymerization of HBFDO to form PBFDO; (b) shows the redox potential screening range of the metal compound.

[0064] Figure 2 These are photos of the reaction solutions obtained in Examples 1 to 7 (from left to right) of the present invention.

[0065] Figure 3 UV-visible-near-infrared absorption spectra of the n-type conjugated polymers in Example 1, Example 3 and Example 6 of the present invention in solution.

[0066] Figure 4 Dynamic light scattering diagrams of the three n-type conjugated polymers in Examples 1, 3, and 6.

[0067] Figure 5 This is the UV-visible-near-infrared absorption spectrum of the carbon nanotube solution purified from the n-type conjugated polymer PBFDO-2 in Example 2.

[0068] Figure 6 The fiber OECT structure diagram (a) and transfer curve (b) prepared by wet spinning of the n-type conjugated polymer PBFDO-2 in Example 2. DETAILED DESCRIPTION

[0069] The present invention will be described in further detail below with reference to the Examples and accompanying drawings, but the embodiments of the present invention are not limited thereto. Where specific conditions are not specified in the Examples, conventional conditions or conditions recommended by the manufacturer were followed. Reagents or instruments used, where the manufacturer is not specified, are commercially available conventional products.

[0070] One of the raw materials in the examples of the present invention, 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione, CAS No. 30272-74-3, was prepared according to the literature (A BDOPV-Based Donor–Acceptor Polymer for High-Performance n-Type and Oxygen-Doped Ambipolar Field-Effect Transistors. Adv.Mater. 2013, 25(45), 6589); the other oxidizing metal compounds used in the examples are all commercially available common chemical raw materials.

[0071] The ratio of the raw materials and the catalytic metal compound used in the present invention is less than or equal to a molar ratio of 1:0.01, such as 1:0.01, 1:0.001, 1:0.0005, etc. Although the catalytic effect of the metal compound is very efficient, its usage is not zero.

[0072] When the raw materials react with the catalytic metal compound, there is no special requirement for the reaction temperature as long as the reaction can proceed, for example: the reaction temperature is 60~150℃.

[0073] After the reaction is completed, no further treatment is required. The stock solution can be used after returning to room temperature and homogenization.

[0074] Example 1

[0075]

[0076] Under air atmosphere, cobalt oxide (0.59 mg, 0.0079 mmol) and 10 mL of dimethyl sulfoxide (DMSO) were added to a round-bottom flask containing benzodifurandione (150 mg, 0.79 mmol). The mixture was heated to 80°C for 7 h. The solution was then returned to room temperature and homogenized at 6000 rpm for 30 min to obtain the n-type conjugated polymer PBFDO-1 with Mn=73 kDa and PDI=2.03.

[0077] Example 2

[0078]

[0079] Under air atmosphere, molybdenum trioxide (1.14 mg, 0.0079 mmol) and 10 mL of dimethyl sulfoxide (DMSO) were added to a round-bottom flask containing benzodifurandione (150 mg, 0.79 mmol). The mixture was heated to 80°C and reacted for 7 h. The solution was then returned to room temperature and homogenized at 6000 rpm for 30 min to obtain the n-type conjugated polymer PBFDO-2 with Mn=47 kDa and PDI=3.56.

[0080] Example 3

[0081]

[0082] Vanadium dioxide (0.65 mg, 0.0079 mmol) and 10 mL of dimethyl sulfoxide (DMSO) were added to a round-bottom flask containing benzodifurandione (150 mg, 0.79 mmol) under air atmosphere. The mixture was heated to 80°C and reacted for 12 h. The solution was then returned to room temperature and homogenized at 6000 rpm for 30 min at room temperature to obtain an n-type conjugated polymer PBFDO-3 with Mn=42 kDa and PDI=5.43.

[0083] Example 4

[0084]

[0085] Under air atmosphere, iron oxide (1.26 mg, 0.0079 mmol) and 10 mL of dimethyl sulfoxide (DMSO) were added to a round-bottom flask containing benzodifurandione (150 mg, 0.79 mmol). The mixture was heated to 80°C for 7 h. The solution was then returned to room temperature and homogenized at 6000 rpm for 30 min to obtain an n-type conjugated polymer PBFDO-4 with Mn = 64 kDa and PDI = 2.76.

[0086] Example 5

[0087]

[0088] Under air atmosphere, cuprous oxide (0.11 mg, 0.00079 mmol) and 10 mL of dimethyl sulfoxide (DMSO) were added to a round-bottom flask containing benzodifurandione (150 mg, 0.79 mmol). The mixture was heated to 80°C for 4 h. The solution was then returned to room temperature and homogenized at 6000 rpm for 30 min to obtain the n-type conjugated polymer PBFDO-5 with Mn=84 kDa and PDI=3.47.

[0089] Example 6

[0090]

[0091] To a round-bottom flask containing benzodifurandione (150 mg, 0.79 mmol) was added silver oxide (1.83 mg, 0.0079 mmol) and 10 mL of dimethyl sulfoxide (DMSO) under air atmosphere. The mixture was heated to 80°C for 4 h. The solution was then returned to room temperature and homogenized at 6000 rpm for 30 min to obtain an n-type conjugated polymer, PBFDO-6, with Mn = 43 kDa and PDI = 2.75.

[0092] Example 7

[0093]

[0094] Under air atmosphere, zinc oxide (0.64 mg, 0.0079 mmol) and 10 mL of dimethyl sulfoxide (DMSO) were added to a round-bottom flask containing benzodifurandione (150 mg, 0.79 mmol). The mixture was heated to 80°C and reacted for 7 h. The solution was then returned to room temperature and homogenized at 6000 rpm for 30 min at room temperature to obtain the n-type conjugated polymer PBFDO-7 with Mn=54 kDa and PDI=3.83.

[0095] Comparative Example 8

[0096]

[0097] Under air, ferric chloride (1.28 mg, 0.0079 mmol) and 10 mL of dimethyl sulfoxide (DMSO) were added to a round-bottom flask containing benzodifurandione (150 mg, 0.79 mmol). The mixture was heated to 100°C and allowed to react for 7 h. The solution was then allowed to return to room temperature and homogenized at 6000 rpm for 30 min at room temperature to yield an n-type conjugated polymer, PBFDO-8, with an Mn of 17 kDa and a PDI of 4.35. In Comparative Example 8, although the redox potential of the ferric ion (-0.037 V) was within the catalyst's preferred potential (-0.8 V to 0.8 V), the metal compound, ferric chloride, was soluble in DMSO, preventing it from providing sufficient reactive sites. Consequently, the catalyst's activity was significantly reduced, preventing it from achieving its intended catalytic effect.

[0098] Figure 2 The UV-visible-near infrared absorption spectra of the three n-type conjugated polymers of Examples 1, 3, and 6 are shown in Figure 3It can be seen that the three n-type conjugated polymers exhibit similar absorption peaks, and all exhibit strong absorption peaks in the near-infrared region, suggesting that their conjugated skeletons contain polaron or bipolaron properties. Figure 4 In this study, we used dynamic light scattering (DLS) to compare the particle sizes of n-type conjugated polymers synthesized using three different metal compound catalysts. The average particle sizes of Examples 1, 3, and 6 were 71.32 nm, 53.21 nm, and 93.29 nm, respectively. The larger particle size distribution indicates a higher degree of polymerization in Example 6, resulting in larger nanoparticles.

[0099] Test Example 1 Solution Conductivity Test

[0100] For the seven batches of n-type conjugated polymers PBFDO-1-7 obtained in Examples 1-7, 40 μL of each solution was dropped onto a pretreated substrate and annealed at 80°C for 60 min. The conductivity data was then collected using a Keithley 4200 SCS parameter analyzer using a four-probe measurement. The results are shown in Table 6 below.

[0101] The seven n-type conjugated polymers PBFDO-1~7 all exhibited electrical conductivities higher than 2000 S / cm at thicknesses below 100 nm, indicating that the metal compounds screened by this method have good catalytic efficacy for this type of polymerization reaction.

[0102] Table 6. Conductivity test of seven n-type conjugated polymers in Examples 1 to 7

[0103]

[0104] Test Example 2: Carbon Nanotube Purification

[0105] 0.3 mL of the n-type conjugated polymer PBFDO-2 from Example 2 and 15 mg of Arc carbon nanotubes were dissolved in 25 mL of o-xylene and ultrasonically dispersed using a cell disruptor. The ultrasonic power was set to 300 W for 30 minutes. During the ultrasonic dispersion process, a circulating cooling device was used to cool the ultrasonic solution, strictly controlling the system temperature to maintain at 0°C. The circulating cooling device included a circulating cooling instrument and a double-walled container. The ultrasonic solution was placed in the double-walled container, and a coolant was circulated between the inner and outer layers of the double-walled container to cool the ultrasonic solution and maintain the system temperature at a fixed level.

[0106] Ultracentrifugation was performed immediately after ultrasonic dispersion at a speed of 30,000 rpm for 30 min at 16°C. The supernatant was extracted and analyzed by UV-visible-near-infrared absorption spectroscopy.

[0107] The M11 region of metallic carbon nanotubes absorbs at 600~800 nm, and the S22 region of semiconductor single-walled carbon nanotubes absorbs at 800~1200 nm. Figure 5 It can be seen that the absorption of the carbon nanotube solution at 600~800 nm is greatly reduced after purification by PBFDO-2, which proves that the metallic carbon nanotubes are removed and the semiconductor carbon nanotubes are effectively purified.

[0108] Test Example 3 Preparation of Conductive Fibers by Wet Spinning and Characterization of OECT Performance

[0109] A 20 mL PBFDO-2 solution (DMSO) was stirred thoroughly for 30 minutes, followed by 30 minutes of ultrasonic treatment to remove bubbles from the solution, resulting in a spinning solution. A 10 mL syringe was then used to draw the spinning solution. The syringe was then attached to a syringe pump and injected at varying injection rates (0.02 mL / min to 0.2 mL / min) into a coagulation bath containing isopropanol, tetrahydrofuran, or ethyl acetate. The solution undergoes a phase transition in the coagulation bath, solidifying into raw fibers, which are then collected on a collection roller. After a secondary coagulation bath soak and stretching, the DMSO is completely removed, resulting in well-formed PBFDO-2 fibers. These fibers can then be subjected to secondary stretching and heated roller annealing to further enhance fiber orientation and mechanical strength. The resulting PBFDO-2 fibers are then collected on a fiber collection roller.

[0110] The organic electrochemical transistor (OECT) device was constructed using the PBFDO-2 fiber prepared as described above. The steps are as follows: first, the PBFDO-2 fiber was constructed on the surface of the SiO2 silicon wafer through van der Waals interaction, then a metal mask was fixed on the fiber, and a gold electrode was constructed by thermal evaporation. Figure 6 The fiber OECT device shown in the figure. The channel length of the fiber OECT device constructed by this method is determined by the mask size (40 μm-200 μm), and the channel width is the fiber diameter (which can be controlled by the nozzle diameter). The output curve and transfer curve of the PBFDO-2 fiber were obtained by probe station and source meter testing, and the quality factor of the fiber OECT device was calculated according to the following formula .

[0111]

[0112] Among them, g m is the transconductance, W is the channel width, L is the channel length, d is the fiber diameter, V Th is the threshold voltage, V GS is the gate drive voltage.

[0113] An example of the output curve of an OECT device based on PBFDO-2 fiber is shown in Figure 2. Figure 6 As shown, the PBFDO-2 fiber exhibits obvious n-type electron transport properties, and the threshold voltage corresponding to this schematic diagram is for , maximum transconductance g m 0.004 s.

[0114] The above test examples illustrate that the n-type conjugated polymer synthesized in the present invention can be widely used in various organic optoelectronic devices.

Claims

1. A method for synthesizing an n-type conductive conjugated polymer, wherein the n-type conductive conjugated polymer is a homopolymer or copolymer obtained by polymerizing one or more monomers represented by formula (I); Formula (I) In formula (I), Ar 1 is a benzene ring or a naphthalene ring; R1 represents Ar 1 One or more substituents, which are the same or different, are selected from hydrogen atoms, halogens, and methyl groups; X and Y are the same or different and are each independently O or S; It is characterized by: In an air atmosphere, one or more monomers represented by formula (I) and a metal compound are dispersed in an organic solvent, and then heated to react to obtain an n-type conductive conjugated polymer, wherein the metal compound serves as a catalyst and is poorly soluble in the organic solvent, and under the reaction conditions, the redox potential of the metal compound satisfies the following relationship: E (Neutral state / polymerized monomer of n-type conductive conjugated polymer) < E (High-valent metal compound / Low-valent metal compound) < E (O2 / H2O); wherein the neutral state of the n-type conductive conjugated polymer is as shown in formula (II): Formula (II) Wherein, n is a positive integer representing the degree of polymerization; Ar in each polymer unit of the polymer of formula (II) 1 , R1, X, and Y are the same or different.

2. The method for synthesizing an n-type conductive conjugated polymer according to claim 1, wherein: The amount of the metal compound used is 1 ppm to 0.01 times the monomer equivalent.

3. The method for synthesizing an n-type conductive conjugated polymer according to claim 1, wherein: The n-type conductive conjugated polymer is poly(benzofurandione) PBFDO. Benzofurandione HBFDO and a metal compound are dispersed in an organic solvent under air atmosphere, and then heated to react. After the reaction, the n-type conductive conjugated polymer PBFDO is obtained; wherein: n is a positive integer representing the degree of polymerization; m is a positive integer, the value of which is lower than n, representing the degree of reduction doping; The redox potential of the metal compound satisfies the following relationship: E (BFDO / HBFDO) < E (High-valent metal compound / Low-valent metal compound) < E (O2 / H2O).

4. The method for synthesizing an n-type conductive conjugated polymer according to claim 3, wherein: Under standard conditions, the redox potential of the metal compound satisfies the following conditions: -2.25 V < E° (high-valent metal compound / low-valent metal compound) <1.23 V.

5. The method for synthesizing an n-type conductive conjugated polymer according to claim 4, wherein: The metal compound is selected from the oxides, halides, sulfides, salts, bases or acid salts of the following metal ions: ； The organic solvent is a polar aprotic solvent, and the metal compound is poorly soluble in the organic solvent.

6. A method for screening a catalyst for catalyzing the polymerization of one or more monomers represented by formula (I) in an organic solvent under air atmosphere to obtain an n-type conductive conjugated polymer: Formula (I) In formula (I), Ar 1 is a benzene ring or a naphthalene ring; R1 represents Ar 1 One or more substituents, which are the same or different, are selected from hydrogen atoms, halogens, and methyl groups; X and Y are the same or different and are each independently O or S; It is characterized by: The following relationship is satisfied from the redox potential: E (Neutral state / polymerized monomer of n-type conductive conjugated polymer) < E (High-valent metal compound / Low-valent metal compound) < E Among the metal compounds of (O2 / H2O), metal compounds that are poorly soluble in the organic solvent are selected as catalysts.

7. The method for screening a catalyst according to claim 6, wherein: The metal compound is selected from the group consisting of oxides, halides, sulfides, salts, bases or acid salts of alkaline earth metals, transition metals, rare earth metals and main group metals.

8. The method for screening a catalyst according to claim 6, wherein: The n-type conductive conjugated polymer is poly(benzofurandione) PBFDO, which is obtained by polymerizing benzofurandione HBFDO. The catalyst used in the polymerization reaction is selected from metal compounds according to the following conditions: 1) Under standard conditions, the redox potential of the metal compound satisfies the following conditions: -2.25 V < E° (high-valent metal compound / low-valent metal compound) <1.23 V; 2) The metal compound is poorly soluble in the organic solvent used in the polymerization reaction.

9. The method for screening a catalyst according to claim 8, wherein: The catalyst was screened from compounds containing the following metal ions: 。 10. An n-type conductive conjugated polymer obtained according to the synthesis method according to any one of claims 1 to 5.

11. Use of the n-type conductive conjugated polymer according to claim 10 in the preparation of organic functional materials and organic electronic devices.

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