Total receptor type conjugated polymer as well as preparation method and application thereof

Abstract

The invention discloses a total acceptor type conjugated polymer and a preparation method and application thereof, the total acceptor type conjugated polymer is an acceptor-acceptor type conjugated polymer based on a sulfur-containing heterocycle isoindigo derivative and benzodifuran diketone, the structural general formula of the total acceptor type conjugated polymer is shown in the specification, in the formula, X is C or N, R1 is a C8-C24 alkane chain, and n is greater than or equal to 1. The total acceptor conjugated polymer is synthesized through aldol condensation polymerization and has good solution processability, the molecular structure has high planarity, the LUMO energy level and the HOMO energy level are reduced due to the electron deficiency capability, and the electron transmission performance of a material can be promoted. The polymer can be used as an electron transport material and is applied to the field of organic field effect transistors.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of organic polymer semiconductor material preparation, and particularly relates to a full acceptor type conjugated polymer and a preparation method and application thereof. BACKGROUND

[0002] Conjugated polymers (CPs) have had a major impact on the field of electronic and photonic devices, with their mechanical flexibility and tunable bandgaps, as well as ease of processing and low cost, opening up new avenues for device fabrication and applications, including organic light-emitting diodes, organic photovoltaics, organic field-effect transistors and bioelectronics, especially for flexible and wearable devices.

[0003] According to the difference of carrier type, the conjugated polymer can be divided into P-type (mainly conducting holes) polymer and N-type (mainly conducting electrons) polymer. In organic electronic devices, P-type conjugated polymers have made great progress, however, the development of N-type semiconductor materials is still far behind, which is mainly because the N-type semiconductor material has poor water and oxygen stability, low electron mobility, and few electron-deficient building blocks. However, the construction of logic circuits usually requires high-performance P-type and N-type materials at the same time. Therefore, the development of electron-transporting conjugated polymers is of great significance to promote the development of conductive polymers. According to previous literature reports, the realization of electron transport of polymer semiconductor material is related to the lowest unoccupied orbital energy level (LUMO) and the highest occupied orbital energy level (HOMO) of the polymer semiconductor material itself. The introduction of strong electron-deficient units in the conjugated polymer can effectively reduce the FMO energy level of the polymer, which is conducive to the effective injection and stable transmission of electrons, and can also effectively resist the oxidation of water and oxygen in the air.

[0004] At present, the N-type polymer semiconductor material still has the defects of insufficient electron transport capacity, few types and high cost, therefore, there is an urgent need for a polymer semiconductor material with strong electron transport capacity. SUMMARY

[0005] The present application aims to provide a full acceptor type conjugated polymer and a preparation method and application thereof, the polymer has low LUMO and HOMO energy levels, and the molecular structure is highly planarized, which is expected to realize long-term stable electron transport characteristics in the air.

[0006] In one aspect of the present application, a full acceptor type conjugated polymer is provided. According to an embodiment of the present application, the full acceptor type conjugated polymer is a acceptor-acceptor type conjugated polymer based on sulfur-containing heterocyclic isatin derivatives and benzodifuran dione, and the structural general formula is as follows:

[0007] ,

[0008] In the formula, X is C or N, and R1 is C⁸ - C⁻¹. 24 Alkane chain, n≥1.

[0009] In addition, a fully acceptor-type conjugated polymer according to the above embodiments of the present invention may also have the following additional technical features:

[0010] In some embodiments of the present invention, R1 is one of 2-ethylhexyl, 2-butylhexyl, 2-hexyloctyl, 4-hexyldecyl, 3-hexylundecyl, 2-octyldecyl, 2-octyldodecyl, 3-octyltridecyl, 2-decyldodecyl, and 2-decyltetradecyl.

[0011] In some embodiments of the present invention, the general structural formula of the sulfur-containing heterocyclic isoindigo derivative is as follows:

[0012] ,

[0013] In the formula, X is C or N, and R1 is C⁸ - C⁻¹. 24 Alkane chain.

[0014] In some embodiments of the present invention, the structural formula of the benzodifurandione is as follows:

[0015] .

[0016] In another aspect of the invention, a method for preparing a fully acceptor-type conjugated polymer is proposed. According to an embodiment of the invention, the method includes the following steps: using a sulfur-containing heterocyclic isoindigo derivative and benzodifuran dione as raw materials, a hydroxyl condensation reaction is carried out in a chlorobenzene solvent at 110 °C to 150 °C under acid catalysis to obtain the fully acceptor-type conjugated polymer.

[0017] In addition, the method for preparing a fully acceptor-type conjugated polymer according to the above embodiments of the present invention may also have the following additional technical features:

[0018] In some embodiments of the present invention, the catalyst of the acid catalyst is p-benzenesulfonic acid.

[0019] In some embodiments of the present invention, the aldol condensation reaction takes 3-7 days.

[0020] In some embodiments of the present invention, the molar ratio of the sulfur-containing heterocyclic indigo derivative, benzodifuran dione, and acid catalyst is 1:1:0.2~1.

[0021] In another aspect of the invention, an application of a fully acceptor-type conjugated polymer is proposed. According to embodiments of the invention, the fully acceptor-type conjugated polymer is used to prepare organic field-effect transistor materials.

[0022] In addition, the application of the fully acceptor-type conjugated polymer according to the above embodiments of the present invention may also have the following additional technical features:

[0023] In some embodiments of the present invention, the fully acceptor conjugated polymer is used as a semiconductor layer material in an organic field-effect transistor with a bottom gate / top contact structure.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1) This invention provides a method for constructing a fully acceptor-type conjugated polymer. The polymer is synthesized by aldol condensation polymerization of a sulfur-containing heterocyclic isoindigo derivative acceptor monomer and a benzodifuran dione acceptor monomer. This polymerization method is simple to synthesize, requires no expensive metal catalysts or toxic organotin reagents, and the resulting polymer contains a large number of electron-withdrawing functional groups. The main chain is constructed from two acceptor units, thus effectively reducing the LUMO energy level of the polymer and significantly improving energy level matching with metal electrodes (such as Au), thereby greatly promoting the polymer's air stability and electron transport capability.

[0026] 2) This invention demonstrates that the carbon-carbon double bond bridging of the backbones of benzodifurandione and sulfur-containing heterocyclic isoindigo derivatives can effectively reduce the LUMO energy level of the polymer, resulting in a highly planar molecular structure that enhances intra-chain carrier transport. Therefore, this achievement can be widely applied in the field of organic field-effect transistors (OFETs).

[0027] 3) This invention introduces two strongly electron-deficient units, A1, a sulfur-containing heterocyclic indigo derivative, and A2, a benzodifuran dione, into the conjugated polymer backbone to form an A1-A2 acceptor-acceptor type conjugated polymer, which can effectively reduce the LUMO energy level of the polymer. Its excellent electron acceptor ability greatly increases the probability of electron transport materials. Attached Figure Description

[0028] Figure 1 The hydrogen spectrum of compound 2 described in Example 1 of this invention;

[0029] Figure 2 The hydrogen spectrum of compound 3 described in Example 1 of this invention;

[0030] Figure 3 The hydrogen spectrum of compound 4 described in Example 1 of this invention;

[0031] Figure 4 The hydrogen spectrum of the fully acceptor-type conjugated polymer described in Example 2 of this invention;

[0032] Figure 5The UV-Vis absorption spectrum of the fully acceptor-type conjugated polymer described in Example 2 of this invention;

[0033] Figure 6 The optimal spatial configuration, electron cloud distribution, and HOMO / LUMO energy level diagram of the fully acceptor conjugated polymer described in Example 2 of this invention are shown.

[0034] Figure 7 This is a schematic diagram of a field-effect transistor device structure in Application Example 1 of the present invention, in which a conjugated polymer is used as the semiconductor material layer. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1

[0037] A method for preparing sulfur-containing heterocyclic indigo derivatives includes the following steps:

[0038] Step 1: Under a nitrogen atmosphere, 3-bromothiophene (3.4 g, 20.6 mmol), 2-decylatetetradecane-1-amine (8 g, 25.1 mmol), copper (0.13 g, 2.06 mmol), cuprous iodide (0.39 g, 2.03 mmol), and tripotassium phosphate (11 g, 51.5 mmol) were dissolved in 40 mL of anhydrous N,N-dimethylethanolamine in a round-bottom flask. The mixture was then reacted at 85 °C for 48 hours. After the reaction was complete, the reaction was cooled to room temperature and quenched dropwise with deionized water. The mixture was extracted with ethyl acetate, and the organic phase was collected. The filtrate was concentrated to obtain an oily crude product. The crude product was separated by silica gel column chromatography using ethyl acetate:petroleum ether = 10:1 as the eluent for rapid column purification to obtain compound 2. The structure of compound 2 was characterized by 1H NMR using deuterated chloroform as the solvent, as shown in the figure. Figure 1 Shown, 1H NMR (300 MHz, CDCl3, ppm) δ: 7.15 (d, J = 4.9 Hz, 1H), 6.62 (d, J = 4.9 Hz, 1H), 5.93 (s, 1H), 3.58 (br s, 1H), 3.01 (d, J = 6.2 Hz, 2H),1.59-1.55 (m, 1H), 1.43-1.37 (m, 40H), 0.96-0.94 (m, 6H).

[0039] Step 2: Under a nitrogen atmosphere and in an ice-water bath, oxaloyl chloride (2.5 g, 19.77 mmol) was dissolved in 10 mL of anhydrous dichloromethane to prepare a solution. Compound 2 (3.5 g, 7.9 mmol) was dissolved in 10 mL of anhydrous dichloromethane to prepare a solution, and the solutions were slowly added dropwise to the oxaloyl chloride / dichloromethane solution. After the addition was complete, the reaction was continued at low temperature for 0.5 h. Triethylamine (4.4 g, 43.49 mmol) was dissolved in 10 mL of anhydrous dichloromethane and diluted to prepare a solution, which was then slowly added dropwise to the reaction system. After the addition was complete, the reaction was continued at low temperature for 1 h, then slowly restored to room temperature, and stirred overnight. After the reaction was complete, deionized water was added dropwise to quench the reaction, and the mixture was extracted with dichloromethane / water. The organic phase was collected, and the filtrate was dried and concentrated to obtain an oily crude product. The crude product was separated by silica gel column chromatography using ethyl acetate:petroleum ether = 1:20 as the eluent. Column chromatography yielded 555.3 mg of an orange-red oily compound 3, with a yield of 15%. The structure of compound 3 was characterized by 1H NMR spectroscopy using deuterated chloroform as the solvent. Figure 2 Shown, 1H NMR (300 MHz, CDCl3, ppm) δ: 7.99 (d, J = 4.9 Hz, 1H), 6.78 (d, J = 5.0 Hz, 1H), 3.63 (t, J = 7.3 Hz, 2H), 1.70 – 1.59 (m, 1H), 1.37 –1.13 (m, 40H), 0.87 (t, J = 7.1 Hz, 6H).

[0040] Step 3: Compound 3 (0.43 g, 0.887 mmol), silver fluoride (0.23 g, 1.862 mmol), and palladium(II) acetate (20 mg, 0.0887 mmol) were added to 10 mL of DMSO and 10 mL of 1,4-dioxane. The mixture was stirred at 90 °C for 24 hours under a nitrogen atmosphere, then cooled to room temperature. The reaction mixture was poured into water, extracted with dichloromethane, and dried over Na₂SO₄. After removing the solvent under reduced pressure, the residue was purified by silica gel chromatography with dichloromethane:petroleum ether as eluent in a 5:1 ratio to give 0.33 g of a deep purple solid, compound 4 (a sulfur-containing heterocyclic isoindigo derivative), in 40% yield. The structure of compound 4 was characterized by 1H NMR using deuterated chloroform as a solvent, as shown in the figure. Figure 3Shown, 1H NMR (300 MHz, CDCl3, ppm) δ: 7.00 (s, 2H), 3.68 (t, J = 7.2 Hz, 4H), 1.68 (m,4H), 1.43 – 1.11 (m, 78H), 0.87 (t, J = 6.8 Hz, 12H).

[0041] The structural formulas of sulfur-containing heterocyclic indigo derivatives are as follows:

[0042] .

[0043] Chemical reaction flow chart as follows Figure 1 As shown, the specific synthesis steps are as follows:

[0044]

[0045] Compound 1 Compound 2 Compound 3 Compound 4

[0046] Example 2

[0047] A method for preparing a fully acceptor-type conjugated polymer includes the following steps:

[0048] Benzadifuran dione (13.6 mg, 0.0715 mmol) and the sulfur-containing heterocyclic isoindigo derivative prepared in Example 1 (70 mg, 0.0715 mmol), along with 5 mL of dry chlorobenzene and p-benzenesulfonic acid (3 mg, 0.025 mmol), were added to a 100 mL polymerization tube. The tube was subjected to three freeze-pump-thaw cycles to remove oxygen, then purged with nitrogen and reacted at 130°C for 3 days. The reaction was cooled to room temperature, and 200 mL of methanol was added to precipitate the solid. The solid was filtered, and the solid was extracted with methanol and n-hexane for 24 hours, followed by Soxhlet extraction with chloroform for 24 hours. Finally, the liquid was rotary evaporated, and the methanol precipitate was used to obtain the fully acceptor conjugated polymer. The structure of the fully acceptor conjugated polymer was characterized by 1H NMR using deuterated chloroform as a solvent. Figure 4 As shown, the H on the polymer backbone exhibits corresponding broad peaks at chemical shifts of 8.65, 6.6, and 3.65, indicating that it is consistent with the NMR of the polymer.

[0049] The structural formula of the fully acceptor-type conjugated polymer is shown below:

[0050] .

[0051] The preparation process of the polymer is shown in the following flowchart:

[0052]

[0053] Figure 5 The figure shows the UV-Vis absorption spectrum of the conjugated polymer. As can be seen from the figure, both the polymer solution and the film exhibit a wide absorption range in the UV spectrum. In the chloroform solution, the polymer has a maximum absorption peak at about 828 nm. The film shows a red shift compared to the solution, indicating that the molecular arrangement is improved due to strong interchain interactions in the solid film. Figure 6 The optimal spatial configuration, electron cloud distribution, and HOMO / LUMO energy levels of the conjugated polymer are shown in the figure. As can be seen from the figure, the polymer structure exhibits high planarity, with dihedral angles between different groups approaching zero, indicating strong intermolecular and intramolecular interactions, which favors molecular packing. Furthermore, simulation calculations of the molecular structure reveal a low LUMO energy level.

[0054] Application Example 1

[0055] The organic field-effect transistor device structure using the conjugated polymer described in Example 2 as the semiconductor material, such as... Figure 7 As shown. This organic field-effect transistor is fabricated using a bottom-gate / top-contact (BG / TC) device structure, with a heavily doped silicon dioxide wafer (SiO2 / Si) as the substrate, Si as the gate, and SiO2 as the insulating layer. Then, a chloroform solution of the conjugated polymer prepared in Example 2 is spin-coated onto the substrate, with a film thickness of about 40 nm. Using a vacuum deposition machine and a mask, a 30-50 nm thick gold electrode is deposited on the substrate with the spin-coated semiconductor film as the source and drain electrodes.

[0056] In summary, the novel fully acceptor conjugated polymer of this invention possesses low LUMO and HOMO energy levels, which typically exhibit good air stability, significantly improve energy level matching with metal electrodes (such as Au), and the reduction in the FMO energy level suppresses hole injection, thereby promoting electron transport. DFT calculations show that this polymer exhibits high planarity and strong intermolecular forces, and UV analysis confirms a low band gap, further demonstrating that this structure can promote charge transport and enhance electron transport capabilities.

[0057] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A full acceptor type conjugated polymer, characterized in that, The full acceptor type conjugated polymer is based on a sulfur-containing heterocyclic isatin derivative and a benzodifuran dione acceptor-acceptor type conjugated polymer, and the structural general formula is as follows: ， wherein X is C or N, R1is C8-C 24 alkane chain, n > 1.

2. The full acceptor type conjugated polymer according to claim 1, characterized in that: The R1 is one of 2-ethylhexyl, 2-butylhexyl, 2-hexyloctyl, 4-hexyldecyl, 3-hexylundecyl, 2-octyldecyl, 2-octyldodecyl, 3-octyltridecyl, 2-decyldodecyl, and 2-decyltetradecyl.

3. The full acceptor type conjugated polymer according to claim 1, characterized in that: The structural general formula of the sulfur-containing heterocyclic isatin derivative is as follows: ， wherein X is C or N, R1is C8-C 24 alkane chain.

4. The full acceptor type conjugated polymer according to claim 1, wherein The structural formula of the benzodifuran dione is as follows: 。 5. A method for preparing the full acceptor type conjugated polymer according to any one of claims 1 to 4, characterized in that: The full acceptor type conjugated polymer is obtained by hydroxy aldehyde polycondensation reaction of the sulfur-containing heterocyclic isatin derivative and the benzodifuran dione as raw materials under acid catalysis in chlorobenzene solvent at 110-150 ℃.

6. The method of claim 5, wherein the method is a method of preparing a full acceptor type conjugated polymer. The catalyst of the acid catalyst is p-toluenesulfonic acid.

7. The method of claim 5, wherein the method is a method of preparing a full acceptor type conjugated polymer. The hydroxy aldehyde polycondensation reaction time is 3-7 days.

8. The method of claim 5, wherein the preparation of a full acceptor type conjugated polymer is characterized by: The molar ratio of the sulfur-containing heterocyclic isatin derivative, the benzodifuran dione, and the acid catalyst is 1:1: (0.2-1).

9. Use of the full acceptor type conjugated polymer according to any one of claims 1 to 4, characterized in that: The full acceptor type conjugated polymer is used for preparing an organic field effect transistor material.

10. The use of the full acceptor type conjugated polymer according to claim 9, characterized in that: The full acceptor type conjugated polymer is used as a semiconductor layer material in an organic field effect transistor with a bottom gate / top contact structure.

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