Conjugated polymer material for organic electrochemical transistor and preparation method thereof

Abstract

The invention provides a conjugated polymer material for an organic electrochemical transistor and a preparation method of the conjugated polymer material, and belongs to the technical field of polymer synthesis. The six-membered amide ring with strong electron-withdrawing property is introduced into the polymer, so that the electron deficiency of the material is improved, the energy level of the polymer material is successfully lowered through introduction of the electron-deficient six-membered amide ring, the electron transmission characteristic of the material is realized, and the ion transmission characteristic of the material is realized through ether oxygen side chain engineering. According to the invention, the skeleton structure is optimized, the crystallinity and energy level of the material are controlled, and efficient transmission of electrons and ions by the material is realized. According to the invention, pyridine is introduced into a main chain of a polymer material, the energy level of the material is effectively lowered, the material shows the characteristics of an n-type material, and the polymer has a water-soluble ether oxygen side chain and can be used as a channel material of an organic electrochemical transistor.

Description

Technical Field

[0001] The invention relates to the technical field of polymer synthesis, and in particular to a conjugated polymer material for an organic electrochemical transistor and a preparation method thereof. Background Art

[0002] In recent years, organic electrochemical transistors based on organic ion-electron hybrid transport materials have the characteristics of low voltage drive (<1V), strong signal amplification capability (transconductance), and can be used in aqueous environments, showing excellent application potential both in vivo and in vitro.

[0003] Thanks to their excellent biocompatibility and high sensitivity, flexible organic electrochemical transistors (OECTs) have shown great potential and broad application prospects in the fields of biomedicine, artificial intelligence and bionics.

[0004] Compared with organic field-effect transistors that can only transmit electrons or holes, OECTs transmit electrons or holes through a conjugated main chain structure and transmit ions through a hydrophilic ether oxygen chain, which makes it an ideal device for mutual conduction of electronic signals and biological signals, connecting electronic devices that rely on charge transfer with organisms that rely on chemical signals, and thus realizing human-computer interconnection. OECTs adopt a mixed ion-electron transfer mode, which can achieve a large amount of charge transfer, effectively reduce the driving voltage and enhance the transconductance of the device, thereby having stronger signal amplification capabilities and promoting its application inside and outside the biological environment. In the development of high-performance OECTs, channel materials are the key factor in determining device performance. At present, one of the central issues of research in this field is to improve device performance by optimizing the structure of channel materials, and many high-performance building blocks and materials have been reported.

[0005] Materials suitable for OECTs can be divided into n-type materials that transport electrons and p-type materials that transport holes. Compared with p-type materials in OECTs, the performance of n-type materials lags far behind, mainly because n-type materials are based on electron-deficient building blocks, which have poor chemical reactivity and are difficult to synthesize and modify. In addition, n-type materials have poor air stability, which is not conducive to the long life of the device. However, n-type OECTs are essential for the construction of high-performance biosensors involving electron transfer and low-power logic complementary circuits. Therefore, there is an urgent need to develop new electron-deficient building blocks for the synthesis of high-performance n-type polymer materials, which can be used as channel materials for n-type OECTs devices to achieve performance comparable to p-type devices, and then be used for more complex circuit integration.

[0006] As an excellent electron-deficient building block in the field of organic optoelectronics, isoindigo has the advantages of moderate energy level, simple preparation and modification, low cost and good stability, and is widely used in active layer materials of organic solar cells, organic field effect transistors and organic electrochemical transistors. However, due to the insufficient electron-withdrawing property and high energy level of isoindigo, materials based on isoindigo building blocks may exhibit N-type or P-type properties and cannot meet the use requirements of organic electrochemical transistors. Summary of the invention

[0007] In order to solve the problems existing in the prior art, the present invention provides a conjugated polymer material for an organic electrochemical transistor. The present invention introduces a strong electron-withdrawing six-membered amide ring to improve the electron-deficient property of the material. The introduction of the electron-deficient six-membered amide ring successfully lowers the energy level of the polymer material, realizes the electronic transmission property of the material, and realizes the ion transmission property of the material through ether oxygen side chain engineering, optimizes the skeleton structure (changes the Ar group), controls the crystallinity and energy level of the material, and realizes the efficient transmission of electrons and ions by the material.

[0008] The conjugated polymer material P-AQM2I for organic electrochemical transistors of the present invention has a chemical structure as shown in Formula 9:

[0009]

[0010] Preferably, Ar in the P-AQM2I includes structures shown in (1-1) to (1-4):

[0011]

[0012] Preferably, R in the P-AQM2I includes structures shown in (2-1) to (2-3):

[0013]

[0014] Wherein m is a natural number from 0 to 10, and n is a natural number from 2 to 6.

[0015] Another object of the present invention is to provide a method for preparing a conjugated polymer material for an organic electrochemical transistor, the preparation method comprising the following steps:

[0016] In a nitrogen atmosphere, a tin reagent, compound 4, Pd2(dba)3, P-(o-tol)3 and anhydrous toluene are mixed and sealed, and then the sealed container is heated to 110-120° C. and stirred for 20-24 hours to react. After the reaction is completed, the mixture is cooled to room temperature, and the obtained product is collected and purified to obtain the conjugated polymer material for an organic electrochemical transistor;

[0017] Preferably, the tin reagent is any one of (3,3'-difluoro-[2,2'-dithiophene]-5,5'-diyl)bis(trimethyltin), 2,5-bis(trimethyltin)thieno[3,2-b]thiophene, 2,5-bis(trimethyltin)thiophene, and 5,5'-bis(trimethyltin)-2,2'-dithiophene.

[0018] Preferably, the molar ratio of the tin reagent, compound 4, Pd2(dba)3, P-(o-tol)3 and anhydrous toluene is 1:1:0.02:0.04:150. 。

[0019] Preferably, the specific steps of collecting and purifying are: adding the product dropwise into methanol at a rate of 3 to 4 mL / min to generate a precipitate, then filtering, extracting the obtained solid with methanol, acetone and chloroform respectively, concentrating the chloroform solution, and adding it dropwise into methanol again at a rate of 3 to 4 mL / min to generate a precipitate, and finally filtering the precipitate and drying it under vacuum to obtain the conjugated polymer material for organic electrochemical transistors.

[0020] Preferably, the preparation method of compound 4 comprises the following steps:

[0021] (1) Under a nitrogen atmosphere, compound 1 is mixed with 4-methylbenzenesulfonic acid-2,5,8,11-tetraoxatridecan-13-yl ester and sodium hydride, added to an organic solvent, and reacted at room temperature overnight; then the organic solvent is removed under vacuum to obtain a crude product, and the crude product is purified to obtain compound 2 (colorless liquid);

[0022] (2) dissolving chromium trioxide in water, adding it to a glacial acetic acid solution of compound 2 at room temperature to react for 4 to 5 hours, extracting the product with dichloromethane after the reaction, collecting the organic phase, drying and purifying to obtain compound 3 (bright yellow solid);

[0023] (3) adding a mixture of 1,4-diacetylpiperazine-2,5-dione and compound 3 to a solvent, adding triethylamine at a temperature of 40 to 45° C. under nitrogen protection, reacting for 3 to 4 hours, cooling to room temperature after the reaction, removing the solvent under reduced pressure, and purifying the obtained crude product to obtain compound 4 (deep red solid);

[0024] The preparation method of the compound 4 is as follows:

[0025]

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention provides a conjugated polymer material for an organic electrochemical transistor and a preparation method thereof. The method of the present invention introduces pyridine into the main chain of the polymer material to effectively lower the energy level of the material so that it exhibits n-type material characteristics, and uses a water-soluble ether oxygen side chain to be used as a channel material for an organic electrochemical transistor, with a maximum of 60.4±2.2mScm -1 The polymer has a number average molecular weight of 10-100KDa, a film absorption of 300-850nm, a minimum unoccupied orbital energy level of 3.90 to 4.15eV, and a maximum occupied orbital energy level of 5.50 to 5.80eV. It can be processed by solution method (scraping, spin coating, drop coating, printing, etc.) to make organic electrochemical transistors, and the normalized transconductance of the device is 5.7 to 64.10mScm -1 The quality factor μC* is between 0.058 and 0.53FV -1 cm -1 s -1 between. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the 1HNMR spectrum of compound 2 in Example 1;

[0029] Figure 2 is the 1HNMR spectrum of compound 3 in Example 1;

[0030] Figure 3 is the 1HNMR spectrum of compound 4 in Example 1;

[0031] Figure 4 Thermogravimetric analysis results of the conjugated polymer materials of the organic electrochemical transistors prepared in Examples 1 to 4;

[0032] Figure 5 AFM morphology images of the conjugated polymer material films of the organic electrochemical transistors prepared in Examples 1 to 4;

[0033] Figure 6 The UV-visible absorption spectra of the solutions of the conjugated polymer materials for the organic electrochemical transistors prepared in Examples 1 to 4;

[0034] Figure 7 The ultraviolet-visible absorption spectra of the conjugated polymer material films of the organic electrochemical transistors prepared in Examples 1 to 4;

[0035] Figure 8 Cyclic voltammetry curves of the conjugated polymer materials of the organic electrochemical transistors prepared in Examples 1 to 4 in 0.1 M NaCl solution;

[0036] Fig. 9The UV-visible absorption spectra of the conjugated polymer materials of the organic electrochemical transistors prepared in Examples 1 to 4 at a voltage of 0V-0.8V;

[0037] Fig.10 Transfer and output curves of OECT devices made of conjugated polymer materials of organic electrochemical transistors prepared in Examples 1 to 4. DETAILED DESCRIPTION

[0038] The present invention provides a conjugated polymer material P-AQM2I for an organic electrochemical transistor, the chemical structure of which is shown in Formula 9:

[0039]

[0040] Preferably, Ar in the P-AQM2I includes structures shown in (1-1) to (1-4):

[0041]

[0042] Preferably, R in the P-AQM2I includes structures shown in (2-1) to (2-3):

[0043]

[0044] Wherein m is a natural number from 0 to 10, and n is a natural number from 2 to 6.

[0045] The present invention also provides a method for preparing a conjugated polymer material for an organic electrochemical transistor, the steps of which are as follows:

[0046] The tin reagent, compound 4, Pd2(dba)3, P-(o-tol)3 and anhydrous toluene are mixed under a nitrogen atmosphere, and the mixture is sealed in a nitrogen environment. The sealed container is then heated to 110-120° C. and stirred for 20-24 hours to react. After the reaction is completed, the mixture is cooled to room temperature, and the obtained product is collected and purified to obtain the conjugated polymer material for an organic electrochemical transistor.

[0047] In a specific embodiment of the present invention, the tin reagent is any one of (3,3'-difluoro-[2,2'-dithiophene]-5,5'-diyl)bis(trimethyltin), 2,5-bis(trimethyltin)thieno[3,2-b]thiophene, 2,5-bis(trimethyltin)thiophene, and 5,5'-bis(trimethyltin)-2,2'-dithiophene.

[0048] In a specific embodiment of the present invention, the molar ratio of the tin reagent, compound 4, Pd2(dba)3, P-(o-tol)3 and anhydrous toluene is 1:1:0.02:0.04:150. 。

[0049] In a specific embodiment of the present invention, the specific steps of collection and purification are: adding the polymer to methanol at a rate of 3 mL / min to generate a precipitate, and filtering it through a filter paper tube in a Soxhlet extractor; using the Soxhlet extractor to extract the polymer with methanol, acetone and chloroform respectively; concentrating the chloroform solution and adding it to methanol again at a rate of 3 mL / min to generate a precipitate; filtering the precipitate and drying it under vacuum to obtain the conjugated polymer material for organic electrochemical transistors.

[0050] In a specific embodiment of the present invention, the preparation method of compound 4 comprises the following steps:

[0051] (1) Under a nitrogen atmosphere, compound 1 (6-bromo-1H-pyrrolo[2,3-b]pyridine) is mixed with 4-methylbenzenesulfonic acid-2,5,8,11-tetraoxatridecan-13-yl ester and sodium hydride, added to an organic solvent, and reacted at room temperature overnight; then the organic solvent is removed under vacuum to obtain a crude product, and the crude product is purified to obtain compound 2 (colorless liquid, 6-bromo-1-(2,5,8,11-tetraoxatridecan-13-yl)-2,3-dihydro-1H-pyrrolo[2,3-b]pyridine);

[0052] (2) dissolving chromium trioxide in water, adding the solution to the glacial acetic acid solution of compound 2 at room temperature to react for 4 to 5 hours, extracting the product with dichloromethane after the reaction, collecting the organic phase, drying and purifying to obtain compound 3 (bright yellow solid, 6-bromo-1-(2,5,8,11-tetrahydrotridecane-13-yl)-1H-pyrrolo[2,3-b]pyridine-2,3-dione);

[0053] (3) adding a mixture of 1,4-diacetylpiperazine-2,5-dione and compound 3 to a solvent, adding triethylamine under nitrogen protection at a temperature of 40 to 45° C., reacting for 3 to 4 hours, cooling to room temperature after the reaction, removing the solvent under reduced pressure, and purifying the obtained crude product to obtain compound 4 (deep red solid, (3Z,6Z)-3,6-bis(6-bromo-2-oxo-1-(2,5,8,11-tetrahydrotridecane-13-yl)-1,2-dihydro-3H-pyrrolo[2,3-b]pyridin-3-ylidene)piperazine-2,5-dione);

[0054] The preparation method of the compound 4 is as follows:

[0055]

[0056] In a specific embodiment of the present invention, R in compound 4 is

[0057] In a specific embodiment of the present invention, the molar ratio of the compound 1 to 4-methylbenzenesulfonic acid-2,5,8,11-tetraoxatridecan-13-yl ester and sodium hydride in step (1) is 1:1:2.1

[0058] In a specific embodiment of the present invention, the organic solvent in step (1) is N,N-dimethylformamide (DMF).

[0059] In a specific embodiment of the present invention, the molar ratio of chromium trioxide to compound 2 in step (2) is 2.5:1, the mass volume ratio of chromium trioxide to water is 0.9 g:3.0 mL; the mass volume ratio of compound 2 to glacial acetic acid is 1.5-1.6 g:40 mL.

[0060] In a specific embodiment of the present invention, the solvent in step (3) is a mixed solvent of N,N-dimethylformamide and chloroform, and the volume ratio of N,N-dimethylformamide to chloroform is 2:1.

[0061] In a specific embodiment of the present invention, the molar ratio of 1,4-diacetylpiperazine-2,5-dione, compound 3 and triethylamine in step (3) is 1:2.5:4.

[0062] The present invention will be further described below in conjunction with the embodiments.

[0063] Example 1

[0064] A method for preparing a conjugated polymer material for an organic electrochemical transistor, comprising the following steps:

[0065] (1) Under a nitrogen atmosphere, compound 1 (6-bromo-1H-pyrrolo[2,3-b]pyridine, 552 mg, 2.8 mmol, 1.0 equiv), 4-methylbenzenesulfonic acid-2,5,8,11-tetraoxatridecan-13-yl ester (1.0 g, 2.8 mmol, 1.0 equiv) and sodium hydride (dispersed in mineral oil at a mass fraction of 60%, 145 mg, 6 mmol, 2.1 equiv) were stirred under magnetic stirring. DMF (15.0 mL) was added and reacted at room temperature overnight; then DMF was removed under vacuum; the crude product was purified by silica gel column chromatography using dichloromethane as eluent to obtain a colorless liquid compound 2 (6-bromo-1-(2,5,8,11-tetrahydrotridecane-13-yl)-2,3-dihydro-1H-pyrrolo[2,3-b]pyridine, 683 mg, 63% yield); H NMR spectrum: Figure 1 ;

[0066] (2) Chromium trioxide (0.9 g, 9.1 mmol, 2.5 equivalents) was dissolved in 3.0 mL of water and added to 40 mL of glacial acetic acid solution containing compound 2 (1.51 g, 0.39 mmol, 1.0 equivalent) at room temperature for 4 hours; after the reaction was completed, the product was extracted with dichloromethane, the organic phase was collected, 10 g of magnesium sulfate was added and dried for 5 minutes; then, the solvent was removed under reduced pressure, and the crude product was purified by column chromatography, eluted with dichloromethane: ethyl acetate (2:1) to obtain a bright yellow solid compound 3 (6-bromo-1-(2,5,8,11-tetrahydrotridecane-13-yl)-1H-pyrrolo[2,3-b]pyridine-2,3-dione, 1.22 g, 75% yield); NMR showed Figure 2 ;

[0067] (3) A mixture of 1,4-diacetylpiperazine-2,5-dione (198 mg, 1.0 mmol, 1.0 equivalent) and compound 3 (1.04 g, 2.5 mmol, 2.5 equivalent) was added to a mixed solvent of DMF (20 mL) and chloroform (10 mL). Under nitrogen protection, triethylamine (4 mmol, 4 equivalent) was injected using a syringe at 45° C. and reacted for 3 hours. After the addition of triethylamine, the originally colorless solution immediately turned red. After completion, the mixture was cooled to room temperature, the solvent was removed under reduced pressure, and the crude product was purified by column chromatography using dichloromethane:ethyl acetate (1:1) as the eluent to obtain a dark red solid compound 4 ((3Z,6Z)-3,6-bis(6-bromo-2-oxo-1-(2,5,8,11-tetrahydrotridecane-13-yl)-1,2-dihydro-3H-pyrrolo[2,3-b]pyridin-3-ylidene)piperazine-2,5-dione, 546 mg, 60% yield); NMR: Figure 3 ;

[0068] (4) In a 25 mL Schlenk tube, a tin reagent (compound 5, (3,3'-difluoro-[2,2'-dithiophene]-5,5'-diyl)bis(trimethyltin), 1.0 equivalent), compound 4 (1.0 equivalent), Pd2(dba)3 (0.02 equivalent), P-(o-tol)3 (0.04 equivalent) and anhydrous toluene (150 equivalent) were added under nitrogen atmosphere and sealed; the sealed tube was heated to 110° C. and stirred for 24 hours; after the reaction mixture was cooled to room temperature, the polymer was precipitated into methanol and filtered through a filter paper cartridge in a Soxhlet extractor; the polymer was extracted with methanol, acetone and chloroform using a Soxhlet extractor; the chloroform solution was concentrated and precipitated into methanol again. The precipitate was filtered and dried under vacuum to give a polymer P-AQM2I-2FT ((3Z,6Z)-3-(6-(3,3'-difluoro-[2,2'-dithiophene]-5-yl)-2-oxo-1-(2,5,8,11-tetrahydrotridecane-13-yl)-1,2-dihydro-3H-pyrrolo[2,3-b]pyridine-3-ylidene)-6-(2-oxo-1-(2,5,8,11-tetrahydrotridecane-13-yl)-1,2-dihydro-3H-pyrrolo[2,3-b]pyridine-3-ylidene)piperazine-2,5-dione), yield: 82%; GPC (HFIP, 40°C) Mn=77.6 kDa, Mw=85.6 Kda, PDI=1.10.

[0069] The preparation process of the polymer P-AQM2I-2FT in step (4) is as shown in formula (2):

[0070]

[0071] Example 2

[0072] A method for preparing a conjugated polymer material for an organic electrochemical transistor, comprising the following steps:

[0073] (1) to (3) are the same as in Example 1;

[0074] (4) According to the method of Example 1, the tin reagent was replaced with 2,5-bis(trimethyltin)thieno[3,2-b]thiophene (Compound 6) to finally obtain the polymer P-AQM2I-2TT ((3Z,6Z)-3-(2-oxo-1-(2,5,8,11-tetraoxytridecane-13-yl)-1,2-dihydro-3H-pyrrolo[2,3-b]pyridine-3-ylidene)-6-(2-oxo-6-(thieno[3,2-b]thiophene-2-yl)-1-(2,5,8,11-tetraoxytridecane-13-yl)-1,2-dihydro-3H-pyrrolo[2,3-b]pyridine-3-ylidene)piperazine-2,5-dione). Yield: 76%; GPC (HFIP, 40°C) Mn=63.2 kDa, Mw=69.5 KDa, PDI=1.10.

[0075] The preparation process of the polymer P-AQM2I-2TT in step (4) is as shown in formula (3):

[0076]

[0077] Example 3

[0078] A method for preparing a conjugated polymer material for an organic electrochemical transistor, comprising the following steps:

[0079] (1) to (3) are the same as in Example 1;

[0080] (4) According to the method of Example 1, the tin reagent was replaced with 2,5-bis(trimethyltin)thiophene (Compound 7), and finally the polymer P-AQM2I-T (black solid, (3Z,6Z)-3-(2-oxo-1-(2,5,8,11-tetraoxytridecane-13-yl)-1,2-dihydro-3H-pyrrolo[2,3-b]pyridine-3-ylidene)-6-(2-oxo-6-(thiophene-2-yl)-1-(2,5,8,11-tetraoxytridecane-13-yl)-1,2-dihydro-3H-pyrrolo[2,3-b]pyridine-3-ylidene)piperazine-2,5-dione was obtained. Yield: 83%; GPC (HFIP, 40°C) Mn=60.6 kDa, Mw=83.2 KDa, PDI=1.37.

[0081] The preparation process of the polymer P-AQM2I-T in step (4) is as shown in formula (4):

[0082]

[0083] Example 4

[0084] A method for preparing a conjugated polymer material for an organic electrochemical transistor, comprising the following steps:

[0085] (1) to (3) are the same as in Example 1;

[0086] (4) According to the method of Example 1, the tin reagent was replaced with 5,5'-bis(trimethyltin)-2,2'-bithiophene (Compound 9) to finally obtain the polymer P-AQM2I-2T ((3Z,6Z)-3-(6-([2,2'-bithiophene]-5-yl)-2-oxo-1-(2,5,8,11-tetraoxytridecane-13-yl)-1,2-dihydro-3H-pyrrolo[2,3-b]pyridin-3-ylidene)-6-(2-oxo-1-(2,5,8,11-tetraoxytridecane-13-yl)-1,2-dihydro-3H-pyrrolo[2,3-b]pyridin-3-ylidene)piperazine-2,5-dione). Yield: 80%; GPC (HFIP, 40°C) Mn=83.9 kDa, Mw=114.3 KDa, PDI=1.36.

[0087] The preparation process of the polymer P-AQM2I-2T in step (4) is as shown in formula (5):

[0088]

[0089] Comparative Example 1

[0090] The prior art PTIDP2T is used as a comparative example.

[0091]

[0092] Generally, conjugated polymers using alkyl side chains are hydrophobic because the carbon and hydrogen elements of the alkyl side chains cannot bind to water molecules. Therefore, conjugated polymers such as PTIDP2T can only be used as channel materials in traditional organic field effect transistor devices. Electrochemical transistor devices use aqueous electrolytes, and the hydrophobic side chains of PTIDP2T reject the entry of hydrated ions, resulting in its lack of ion doping ability and inability to be used as channel materials in organic electrochemical transistors. The main chain of the polymer material prepared by the present invention introduces pyridine, which effectively lowers the energy level of the material, so that it exhibits the characteristics of an n-type material that transmits electrons, and uses water-soluble ether oxygen side chains in the side chains. Since the oxygen atoms in the ether oxygen side chains can form hydrogen bonds with water molecules, they have excellent hydrophilicity and can induce the entry and doping of hydrated ions, thereby improving the conductivity of the material in an aqueous electrolyte solution. Therefore, the polymer material prepared by the present invention can be used as a channel material for an organic electrochemical transistor, with a maximum of 60.4±2.2mS cm -1 The normalized transconductance of .

[0093] The following experiments were performed on the polymer materials prepared in Examples 1 to 4:

[0094] (1) The polymer was subjected to thermogravimetric analysis. The results are shown in Figure 4 , Figure 4 It shows that the prepared polymer has good thermal stability, and the 5% mass loss temperature is above 350 degrees.

[0095] (2) 6 mg of the polymer material was dissolved in 1.0 mL of hexafluoroisopropanol to prepare a solution, which was first spin-coated at a speed of 500 rpm for 5 s and then at a speed of 1000 rpm for 30 s. The solution was spin-coated onto a glass substrate to obtain a film with a thickness of about 45 nm. The AFM morphology of the film is shown in FIG. Figure 5 ,from Figure 5 It can be seen that the polymer material has good film-forming property, and a dense and smooth film can be prepared by spin coating.

[0096] (3) 6 mg of the polymer material was dissolved in 1.0 mL of chloroform to obtain a solution, and the solution was subjected to UV-visible-near infrared absorption spectroscopy analysis to obtain the UV-visible absorption spectrum of the polymer solution as shown in FIG. Figure 6 .from Figure 6 It can be seen that all polymers exhibit similar π-π* absorption peaks in solution, and are located at similar wavelengths: 400nm for P-AQM2I-2FT, 395nm for P-AQM2I-TT, 399nm for P-AQM2I-T, and 402nm for P-AQM2I-2T. However, due to the differences in polymer molecular stacking, the intramolecular charge transfer (ICT) absorption peaks show significant changes. Unlike P-AQM2I-2FT, which only shows one ICT absorption peak at 623nm, P-AQM2I-TT exhibits a strong ICT absorption peak at 632nm and a weaker shoulder peak at about 720nm. Obvious shoulders are also observed at 700nm for P-AQM2I-2T and 750nm for P-AQM2I-T.

[0097] (4) The film prepared in experiment (2) was subjected to UV-visible-near infrared absorption spectroscopy analysis to obtain the UV-visible absorption spectrum of the polymer film as shown in Figure 7 ,from Figure 7It can be seen that the four polymers exhibit absorption spectra similar to their solution states, showing significant absorption peaks at 400nm and 700nm. Due to stronger molecular aggregation in the film environment, the four polymer films show more obvious aggregation-induced absorption peaks in the wavelength range of 700 to 800nm ​​compared with the solution state. In addition, the absorption starting points of these four polymer films are located at 786nm for P-AQM2I-2FT, 818nm for P-AQM2I-TT, 773nm for P-AQM2I-T, and 835nm for P-AQM2I-2T, respectively. Based on this, the optical band gaps of these materials are calculated to be 1.58eV for P-AQM2I-2FT, 1.51eV for P-AQM2I-TT, 1.60eV for P-AQM2I-T, and 1.48eV for P-AQM2I-2T, respectively.

[0098] (5) 6 mg of the polymer material was dissolved in 1.0 mL of hexafluoroisopropanol to prepare a solution, which was first spin-coated at 500 rpm for 5 s and then at 1000 rpm for 30 s. The solution was spin-coated onto a glass substrate to obtain a film with a thickness of about 45 nm. The film was subjected to cyclic voltammetry analysis at a speed of 0.01 V / s from 0 V to -0.8 V in a 0.1 M NaCl solution using Ag / AgCl as a reference electrode. The cyclic voltammetry curve obtained was as follows: Figure 8 .

[0099] right Figure 7 and Figure 8 The energy levels of the four polymers can be calculated by analysis. Given the significant electron-withdrawing properties of the AQM2I building block, the lowest unoccupied molecular orbital (LUMO) energy levels of all four polymers are below the critical threshold of 4.0 eV (P-AQM2I-2FT is -4.12 eV, P-AQM2I-TT is -4.02 eV, P-AQM2I-T is -4.07 eV, and P-AQM2I-2T is -4.05 eV). In addition, by comparing the energy levels of P-AQM2I-T and its aza-isoindigo analog gAIID-T (HOMO is -5.30 eV, LUMO is -3.84 eV), we can find that the introduction of the strongly electron-deficient quinone-type six-membered ring can effectively reduce the HOMO (0.37 eV) and LUMO (0.23 eV), thereby obtaining a wider band gap of 1.60 eV. The widening of the band gap should be attributed to the cross-conjugation of the quinone-type six-membered ring.

[0100] (6) 6 mg of the polymer material was dissolved in 1.0 mL of hexafluoroisopropanol to prepare a solution, which was first spin-coated at a speed of 500 rpm for 5 s and then at a speed of 1000 rpm for 30 s. The solution was spin-coated onto an ITO glass substrate to obtain a film with a thickness of about 50 nm. The film was subjected to UV-visible-near infrared spectroelectrochemical testing in 2.0 mL of 0.1 M NaCl solution. The results were as follows: Fig. 9 (upper left P-AQM2I-2FT, upper right P-AQM2I-TT, lower left P-AQM2I-T, lower right P-AQM2I-2T), Fig. 9 The electrochemical doping mechanism of the polymer can be characterized. Fig. 9 It can be seen that as the electrode voltage increases from 0 to -0.8V, the intensities of the π-π* absorption peak and the ICT absorption peak decrease at different amplitudes, while new absorption peaks appear at 900-1000nm, proving that polarons are gradually formed. This phenomenon indicates that all four polymers can be effectively electrochemically doped when voltage is applied, indicating that they have the potential to be used as active layer materials in organic electrochemical transistors (OECTs). In addition, the polaron absorption peaks of P-AQM2I-T and P-AQM2I-TT appear at less negative voltages, indicating that they are easier to dope. In contrast, P-AQM2I-2T and P-AQM2I-2FT exhibit polaron absorption peaks at more negative voltages and rapidly enhance with increasing voltage, demonstrating their strong doping capabilities.

[0101] (7) These four polymers were dissolved in hexafluoroisopropanol to prepare a solution with a concentration of 6 mg / L. The solution was then spin-coated on a glass substrate with a gold electrode of size 187500 (L) × 20 (W) μm deposited thereon to fabricate an organic electrochemical transistor (OECT) with these polymers as the active layer. The transistor structure was glass substrate / gold electrode (100 nm) / polymer film (50-70 nm). The performance of the device was tested using Ag / AgCl particle electrodes as gate electrodes in a 0.1 M NaCl aqueous solution. The transfer and output curves were obtained as shown in FIG. Fig.10 The P-AQM2I-2T-based OECT device exhibited the highest normalized transconductance (gm,norm) of 60.4±2.2mScm -1 , while the normalized transconductance of the device using P-AQM2I-2T is slightly lower, at 12.13±2.82mScm-1, and the normalized transconductance of the device based on P-AQM2I-2FT is 5.76±1.20mScm -1The threshold voltages of the devices are 0.52 V for P-AQM2I-2T, 0.50 V for P-AQM2I-2FT, and 0.42 V for P-AQM2I-TT). P-AQM2I-TT and AQM2I-2FT exhibit comparable μC, which are 0.070 ± 0.015 FV, respectively. -1 cm -1 s -1 and 0.058±0.017FV -1 cm -1 s -1 , while P-AQM2I-2T showed the highest μC, which was 0.45±0.005FV -1 cm -1 s -1 , almost an order of magnitude higher than P-AQM2I-TT and AQM2I-2FT.

[0102] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A conjugated polymer material P-AQM2I for an organic electrochemical transistor, characterized in that: The chemical structure is shown in formula 9:

2. The conjugated polymer material P-AQM2I for organic electrochemical transistor according to claim 1, characterized in that: Ar in the P-AQM2I includes structures shown in (1-1) to (1-4):

3. The conjugated polymer material P-AQM2I for organic electrochemical transistor according to claim 1, characterized in that: The R in the P-AQM2I includes the structures shown in (2-1) to (2-3): Wherein m is a natural number from 0 to 10, and n is a natural number from 2 to 6.

4. The method for preparing a conjugated polymer material for an organic electrochemical transistor according to any one of claims 1 to 3, characterized in that: The following steps are involved: In a nitrogen atmosphere, the tin reagent, compound 4, Pd2(dba)3, P-(o-tol)3 and anhydrous toluene are mixed and sealed, and then the sealed container is heated to 110-120°C and stirred for 20-24 hours to react. After the reaction is completed, it is cooled to room temperature, and the obtained product is collected and purified to obtain the conjugated polymer material for organic electrochemical transistors.

5. The method for preparing a conjugated polymer material for an organic electrochemical transistor according to claim 4, characterized in that: The tin reagent is any one of (3,3'-difluoro-[2,2'-dithiophene]-5,5'-diyl)bis(trimethyltin), 2,5-bis(trimethyltin)thieno[3,2-b]thiophene, 2,5-bis(trimethyltin)thiophene, and 5,5'-bis(trimethyltin)-2,2'-dithiophene.

6. The method for preparing a conjugated polymer material for an organic electrochemical transistor according to claim 4, characterized in that: The molar ratio of the tin reagent, compound 4, Pd2(dba)3, P-(o-tol)3 and anhydrous toluene is 1:1:0.02:0.04:150 。 7. The method for preparing a conjugated polymer material for an organic electrochemical transistor according to claim 4, characterized in that: The specific steps of the collection and purification are: adding the product dropwise into methanol at a speed of 3 to 4 mL / min to generate a precipitate, then filtering, extracting the obtained solid with methanol, acetone and chloroform respectively, concentrating the chloroform solution, and adding it dropwise into methanol again at a speed of 3 to 4 mL / min to generate a precipitate, and finally filtering the precipitate and drying it under vacuum to obtain the conjugated polymer material for organic electrochemical transistors.

8. The method for preparing a conjugated polymer material for an organic electrochemical transistor according to claim 4, characterized in that: The preparation method of compound 4 comprises the following steps: (1) under a nitrogen atmosphere, compound 1 is mixed with 4-methylbenzenesulfonic acid 2,5,8,11-tetraoxatridecan-13-yl ester and sodium hydride, added to an organic solvent, and reacted at room temperature overnight; then the organic solvent is removed under vacuum to obtain a crude product, and the crude product is purified to obtain compound 2; (2) dissolving chromium trioxide in water, adding the solution to the compound 2 in glacial acetic acid to react for 4 to 5 hours at room temperature, extracting the product with dichloromethane after the reaction, collecting the organic phase, drying and purifying to obtain compound 3; (3) adding a mixture of 1,4-diacetylpiperazine-2,5-dione and compound 3 to a solvent, adding triethylamine at a temperature of 40 to 45° C. under nitrogen protection, reacting for 3 to 4 hours, cooling to room temperature after the reaction, removing the solvent under reduced pressure, and purifying the obtained crude product to obtain compound 4; The preparation method of the compound 4 is as follows:

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