Novel flexible stretchable polymer as well as preparation method and application thereof

Abstract

The invention discloses a novel flexible stretchable polymer as well as a preparation method and application thereof, and belongs to the technical field of organic semiconductor materials. The flexible stretchable polymer disclosed by the invention can be applied to preparation of an organic semiconductor layer, a field effect transistor prepared by taking the polymer disclosed by the invention as the organic semiconductor layer has an excellent electron transmission characteristic and a good stretchable characteristic, and the highest electron mobility is 0.42 cm < 2 >. V <-1 >. S <-1 >; the method has a wide application prospect when being applied to the stretchable organic field effect transistor. In addition, the polymer shown in the formula (I) is subjected to amino protection, bromination, deprotection, condensation of anhydride and amine and other reactions to obtain a corresponding flexible monomer, and the flexible monomer is prepared through Stille copolymerization. The synthesis route is simple to operate, few in synthesis steps, high in yield and suitable for large-scale synthesis.

Description

Technical Field

[0001] This invention belongs to the field of organic semiconductor materials technology, and particularly relates to a novel flexible stretchable polymer and its preparation method and application. Background Technology

[0002] Semiconductors are materials that lie between conductors and insulators, and due to their unique electrical properties, they are widely used in many fields such as medicine, displays, storage, communications, and energy. As a crucial foundational material for modern electronic devices, semiconductors have seen increasingly broader applications and a larger market size with continuous technological advancements and rapid economic development. Thanks to the continuous development and progress of semiconductor technology and semiconductor-based devices and products (primarily transistors and electronic computers), modern society has undergone the baptism of the information technology revolution, with a significant increase in the level of intelligence and informatization compared to the past. These changes have profoundly altered people's lifestyles and further propelled the development and progress of human society. In current commercial applications, most semiconductors are based on inorganic materials such as selenium, germanium, and silicon. However, due to their inherent rigidity, these materials cannot meet the application requirements of specific devices, especially flexible electronic devices. On the other hand, as devices such as transistors based on traditional inorganic semiconductors are gradually approaching their physical limits, "Moore's Law" is gradually becoming ineffective. Therefore, with the expansion of the flexible market and the increasing demand for electronic products with high performance, lightweight, and wearable characteristics, the search for and development of next-generation semiconductor materials is imperative.

[0003] Organic semiconductor materials are a novel type of semiconductor material, attracting widespread attention from researchers due to their ease of synthesis, tunable band gap, and readily modifiable structure. Based on molecular weight, organic semiconductor materials can be divided into small-molecule organic semiconductor materials and polymeric organic semiconductor materials. Small-molecule semiconductor materials are easy to synthesize and purify, but film formation and solution processing are more difficult. In contrast, polymeric semiconductor materials, although more complex to synthesize and purify, possess excellent film-forming properties and solution processability. Furthermore, through molecular design and structural modification, researchers can obtain a vast number of small-molecule organic and polymeric semiconductor materials, from which they can acquire materials with desired optoelectronic properties or superior device performance.

[0004] Organic field-effect transistors (OFETs) are important devices in organic electronics. They are characterized by using organic semiconductor materials as the semiconductor layer, and adjusting the channel current by changing the gate voltage. OFETs mainly consist of a substrate, gate, source / drain electrodes, an insulating layer, and an organic semiconductor layer. The performance of OFETs is generally measured by several performance parameters, including carrier mobility (μ) and on / off ratio (Ig). on / I off ) and threshold voltage (V TH ). Where μ and I on / I off The higher the value of V, TH The closer the absolute value of the coefficient of performance (COP) is to 0, the better the performance of the OFETs. Based on the different types of carrier transport in the semiconductor layer, OFETs can be further divided into p-type OFETs, n-type OFETs, and bipolar OFETs, corresponding to p-type organic semiconductor materials, n-type organic semiconductor materials, and bipolar organic semiconductor materials, respectively. However, there is a serious imbalance in the development of these three types of materials. For p-type semiconductor materials, small molecule and polymer materials based on rubrene and poly(3-hexylthiophene) (P3HT) exhibit excellent carrier mobility, good device stability, and unique optoelectronic properties, and have the potential for further commercialization and large-scale production. In contrast, the carrier mobility and device stability of n-type and bipolar organic semiconductor materials are significantly lower than those of p-type semiconductor materials. Therefore, the development of high-performance n-type and bipolar semiconductor materials is currently a major research hotspot in academia.

[0005] Stretchable OFETs have gradually evolved from OFETs. Compared to OFETs, stretchable OFETs require all components of the transistor (substrate, gate, source / drain electrodes, organic semiconductor layer, insulating layer, etc.) to possess stretchability and mechanical stability, which places high demands on device fabrication and optimization. As the core material of stretchable OFETs, polymer semiconductors, in addition to needing the mobility and stability of conventional OFETs, must also possess good mechanical properties, maintaining a certain range of carrier mobility during stretching deformation. For stretchable OFETs, the performance of n-type and bipolar organic semiconductor materials lags behind that of p-type organic semiconductor materials. Therefore, developing n-type polymer organic semiconductor materials that combine high carrier mobility and good stretchability is of great significance for the development of stretchable OFETs and, consequently, their application in fields such as electronic skin. Summary of the Invention

[0006] In view of this, the present invention discloses a novel flexible and stretchable polymer, its preparation method, and its applications. The present invention adopts the following technical solution: A polymer having the structural formula shown in formula (I): In formula (I), X is 0 or 0.1, Ar is a disubstituted aromatic ring diimide group, and n is 5 to 200.

[0007] Further, in formula (I), Ar is 2,6-disubstituted pyrrolo[3,4-f]isoindole-1,3,5,7(2H,6H)-tetraone or 2,7-disubstituted benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone.

[0008] A method for preparing the polymer shown in formula (I) above, the method comprising the following steps: S1. In an inert atmosphere, 2-thiophene ethylamine and triethylamine are dissolved in an organic solvent, and di-tert-butyl dicarbonate is slowly added and stirred until fully reacted to obtain reaction solution S1. The reaction solution S1 is extracted, dried, and purified by column chromatography to obtain the intermediate shown in formula (II), where Boc in formula (II) is a tert-butyl carbonate group. S2. In an inert atmosphere, the intermediate shown in formula (II) is dissolved in an organic solvent, N-bromosuccinimide (NBS) is added, and the mixture is stirred until it reacts completely to obtain the S2 reaction solution. The S2 reaction solution is extracted, dried, and purified by column chromatography to obtain the intermediate shown in formula (III), where Boc in formula (III) is tert-butyl carbonate. S3. In an inert atmosphere, the intermediate shown in formula (III) is dissolved in an organic solvent, hydroiodic acid solution is added, and the mixture is stirred until the reaction is complete. After the reaction is complete, reaction solution S3 is obtained. Reaction solution S3 is extracted, dried, and purified by column chromatography to obtain intermediate shown in formula (IV). S4. Under an inert atmosphere, the intermediate shown in formula (IV) is dissolved in glacial acetic acid, and 1H,3H-benzo[1,2-c:4,5-c']difuran-1,3,5,7-tetraone is added. The mixture is stirred and heated under reflux overnight. After the reaction is completed, reaction solution S4 is obtained. Reaction solution S4 is extracted, dried, and purified by column chromatography to obtain the flexible monomer shown in formula (V). In an inert atmosphere, the intermediate shown in formula (IV) was dissolved in glacial acetic acid, and 1,4,5,8-naphthalenetetracarboxylic anhydride was added. The mixture was stirred and heated under reflux overnight. After the reaction was completed, the S5 reaction solution was obtained. The S5 reaction solution was extracted, dried, and purified by column chromatography to obtain the flexible monomer shown in formula (VI). In an inert atmosphere, under the catalysis of palladium catalyst and phosphine ligand, the compound shown in formula (VII), the compound shown in formula (VIII), the flexible monomer shown in formula (V), and the flexible monomer shown in formula (VI) are subjected to Stille copolymerization in a certain molar ratio to obtain the polymer shown in formula (I).

[0009] Further, the organic solvent in step S1 is anhydrous dichloromethane, and the concentration of 2-thiopheneethylamine in the organic solvent is 0.2~1 mol / L; the molar ratio of 2-thiopheneethylamine, triethylamine, and di-tert-butyl dicarbonate is 1:1.2~2:1.1~1.5; the temperature at which di-tert-butyl dicarbonate is added and the reaction temperature are both room temperature; the reaction time in step S1 is 72~96 h.

[0010] Further, the organic solvent in step S2 is N,N-dimethylformamide (DMF), and the concentration of the intermediate shown in formula (II) in the organic solvent is 0.5~1 mol / L; the molar ratio of the intermediate shown in formula (II) to the NBS is 1:1~1.2; the temperature at which NBS is added and the reaction temperature are both room temperature; the reaction time in step S2 is overnight (10-20 hours).

[0011] Further, the organic solvent in step S3 is 1,4-dioxane, and the concentration of the intermediate shown in formula (III) in the organic solvent is 0.2~0.5 mol / L; the volume ratio of the 1,4-dioxane solution of the intermediate shown in formula (III) to the hydroiodic acid solution is 2~3:1, preferably 2.5:1, and the hydroiodic acid is an aqueous solution with a mass fraction of 55~57%; the temperature at which hydroiodic acid is added and the reaction temperature are both room temperature; the reaction time in step S3 is 2~5 h.

[0012] Further, in steps S4 and S5, the organic solvent used is glacial acetic acid, and the concentration of the intermediate shown in formula (IV) in the organic solvent is 0.01~0.1 mol / L; the molar ratio of the intermediate shown in formula (IV) to the acid anhydride is 2~2.2:1; the acid anhydride is added at room temperature, and the reaction temperature is controlled by heating and reflux; the reaction time of step S4 is overnight (10-20 hours).

[0013] Further, in step S6, the palladium catalyst is selected from at least one of tetra(triphenylphosphine)palladium and tri(dibenzylacetone)dipalladium, preferably tri(dibenzylacetone)dipalladium; the phosphine ligand is tri(o-tolyl)phosphine or triphenylphosphine, preferably tri(o-tolyl)phosphine; The molar ratio of the compounds shown in formulas (VII), (VIII), (V), and (VI), the palladium catalyst, and the phosphine ligand is (1-xy): 1:x:y:0.01~0.10:0.10~0.50; where 0≤x<1, 0≤y<1, and xy = 0; The Stille copolymerization reaction is carried out at a temperature of 90-120 °C, preferably 115 °C; the reaction time is 24-72 h, preferably 72 h; the inert atmosphere includes a nitrogen atmosphere or an argon atmosphere; the reaction is carried out in a solvent; the solvent is selected from at least one of toluene and chlorobenzene, preferably chlorobenzene.

[0014] The application of the polymer shown in formula (I) above in the fabrication of stretchable organic field-effect transistors.

[0015] A stretchable organic field-effect transistor, wherein the organic semiconductor layer of the organic field-effect transistor is prepared from the polymer shown in formula (I) above; the thickness of the organic semiconductor layer is 10~50 nm.

[0016] The beneficial effects of this invention are: 1. The polymer flexible monomer of formula (I) prepared by the present invention can be synthesized in high yield via the above technical route. Other synthetic raw materials required for the polymer of formula (I) have mature synthetic technical routes or can be purchased in large quantities through commercial channels, which facilitates large-scale synthesis. 2. The polymer of formula (I) prepared by this invention has good thermal stability, broad UV-Vis absorption properties, low lowest unoccupied molecular orbital (LUMO) energy level and highest occupied molecular orbital (HOMO) energy level, good solution processability, and can be used to prepare high-performance stretchable OFETs by solution method; 3. The stretchable OFETs prepared by the present invention using the polymer shown in formula (I) as the semiconductor layer have excellent maximum electron mobility (µF). e, max (Optimal is µ) e, max It is 0.42 cm. 2 V –1 s –1 It has broad application prospects. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the synthetic route of the polymer shown in formula (Ⅰ) of the present invention; Figure 2 This is a schematic diagram of the ultraviolet-visible absorption spectra of polymers P0-2T, P1-2T, and P2-2T in chlorobenzene solution in the embodiments of the present invention; Figure 3This is a schematic diagram of the ultraviolet-visible absorption spectra of polymer P0-2T, P1-2T, and P2-2T films in the embodiments of the present invention; Figure 4 This is a schematic diagram of the thermogravimetric analysis curves of polymers P0-2T, P1-2T, and P2-2T in the embodiments of the present invention; Figure 5 This is a schematic diagram of the differential scanning calorimetry curve of polymer P0-2T in an embodiment of the present invention; Figure 6 This is a schematic diagram of the differential scanning calorimetry curve of polymer P1-2T in an embodiment of the present invention; Figure 7 This is a schematic diagram of the differential scanning calorimetry curve of polymer P2-2T in an embodiment of the present invention; Figure 8 This is a schematic diagram of the cyclic voltammetry curves of polymers P0-2T, P1-2T, and P2-2T in the embodiments of the present invention; Figure 9 This is a schematic diagram of the two-dimensional grazing incidence X-ray diffraction (2D-GIWAX) patterns of polymers P0-2T, P1-2T, and P2-2T in embodiments of the present invention. Figure 10 The diagram shows the transfer characteristic curves (A) and output characteristic curves (B) of the stretchable OFETs based on the representative polymer P0-2T of this invention. Figure 11 The diagram shows the transfer characteristic curves (A) and output characteristic curves (B) of the stretchable OFETs based on the representative polymer P1-2T of this invention. Figure 12 The diagram shows the transfer characteristic curves (A) and output characteristic curves (B) of the stretchable OFETs based on the representative polymer P2-2T of this invention. Figure 13 This is a schematic diagram of the polymer structure shown in formula (I) of the present invention. Detailed Implementation

[0019] To better understand the technical solution of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0020] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples can be purchased commercially. The reaction substrate compound (3E,7E)-3,7-bis(6-bromo-1-(4-octadecylteicosyl)-2-oxo-1,2-dihydro-3H-pyrrolo[2,3-b]pyridin-3-ylidene)-3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione used in the following examples was synthesized according to the literature Macromolecules, 2018, 51(15), 5704-5712. All other reaction substrates, solvents, catalysts and ligands used can be obtained commercially.

[0021] Example 1 A polymer having the structural formula shown in formula (I), as follows: Figure 13 As shown: In formula (I), X is 0 or 0.1, Ar is a disubstituted aromatic ring diimide group, and n is 5 to 200.

[0022] Further, in formula (I), Ar is 2,6-disubstituted pyrrolo[3,4-f]isoindole-1,3,5,7(2H,6H)-tetraone or 2,7-disubstituted benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone.

[0023] The structural formulas of the polymers shown in formula (Ⅰ) are specifically as shown in formulas P0-2T, P1-2T, and P2-2T. The structures of formulas P0-2T, P1-2T, and P2-2T are as follows: Figure 1 As shown.

[0024] A method for preparing the polymer shown in formula (I) above, the method comprising the following steps: S1. In an inert atmosphere, 2-thiophene ethylamine and triethylamine are dissolved in an organic solvent, and di-tert-butyl dicarbonate is slowly added and stirred until fully reacted to obtain reaction solution S1. The reaction solution S1 is extracted, dried, and purified by column chromatography to obtain the intermediate shown in formula (II), where Boc in formula (II) is a tert-butyl carbonate group. S2. In an inert atmosphere, the intermediate shown in formula (II) is dissolved in an organic solvent, N-bromosuccinimide (NBS) is added, and the mixture is stirred until it reacts completely to obtain the S2 reaction solution. The S2 reaction solution is extracted, dried, and purified by column chromatography to obtain the intermediate shown in formula (III), where Boc in formula (III) is tert-butyl carbonate. S3. In an inert atmosphere, the intermediate shown in formula (III) is dissolved in an organic solvent, hydroiodic acid solution is added, and the mixture is stirred until the reaction is complete. After the reaction is complete, reaction solution S3 is obtained. Reaction solution S3 is extracted, dried, and purified by column chromatography to obtain intermediate shown in formula (IV). S4. Under an inert atmosphere, the intermediate shown in formula (IV) is dissolved in glacial acetic acid, and 1H,3H-benzo[1,2-c:4,5-c']difuran-1,3,5,7-tetraone is added. The mixture is stirred and heated under reflux overnight. After the reaction is completed, reaction solution S4 is obtained. Reaction solution S4 is extracted, dried, and purified by column chromatography to obtain the flexible monomer shown in formula (V). In an inert atmosphere, the intermediate shown in formula (IV) was dissolved in glacial acetic acid, and 1,4,5,8-naphthalenetetracarboxylic anhydride was added. The mixture was stirred and heated under reflux overnight. After the reaction was completed, the S5 reaction solution was obtained. The S5 reaction solution was extracted, dried, and purified by column chromatography to obtain the flexible monomer shown in formula (VI). In an inert atmosphere, under the catalysis of palladium catalyst and phosphine ligand, the compound shown in formula (VII), the compound shown in formula (VIII), the flexible monomer shown in formula (V), and the flexible monomer shown in formula (VI) are subjected to Stille copolymerization in a certain molar ratio to obtain the polymer shown in formula (I).

[0025] Further, the organic solvent in step S1 is anhydrous dichloromethane, and the concentration of 2-thiopheneethylamine in the organic solvent is 0.2~1 mol / L; the molar ratio of 2-thiopheneethylamine, triethylamine, and di-tert-butyl dicarbonate is 1:1.2~2:1.1~1.5; the temperature at which di-tert-butyl dicarbonate is added and the reaction temperature are both room temperature; the reaction time in step S1 is 72~96 h.

[0026] Further, the organic solvent in step S2 is N,N-dimethylformamide (DMF), and the concentration of the intermediate shown in formula (II) in the organic solvent is 0.5~1 mol / L; the molar ratio of the intermediate shown in formula (II) to the NBS is 1:1~1.2; the temperature at which NBS is added and the reaction temperature are both room temperature; the reaction time in step S2 is overnight (10-20 hours).

[0027] Further, the organic solvent in step S3 is 1,4-dioxane, and the concentration of the intermediate shown in formula (III) in the organic solvent is 0.2~0.5 mol / L; the volume ratio of the 1,4-dioxane solution of the intermediate shown in formula (III) to the hydroiodic acid solution is 2~3:1, preferably 2.5:1, and the hydroiodic acid is an aqueous solution with a mass fraction of 55~57%; the temperature at which hydroiodic acid is added and the reaction temperature are both room temperature; the reaction time in step S3 is 2~5 h.

[0028] Further, in steps S4 and S5, the organic solvent used is glacial acetic acid, and the concentration of the intermediate shown in formula (IV) in the organic solvent is 0.01~0.1 mol / L; the molar ratio of the intermediate shown in formula (IV) to the acid anhydride is 2~2.2:1; the acid anhydride is added at room temperature, and the reaction temperature is controlled by heating and reflux; the reaction time of step S4 is overnight (10-20 hours).

[0029] Further, in step S6, the palladium catalyst is selected from at least one of tetra(triphenylphosphine)palladium and tri(dibenzylacetone)dipalladium, preferably tri(dibenzylacetone)dipalladium; the phosphine ligand is tri(o-tolyl)phosphine or triphenylphosphine, preferably tri(o-tolyl)phosphine; The molar ratio of the compounds shown in formulas (VII), (VIII), (V), and (VI), the palladium catalyst, and the phosphine ligand is (1-xy):1:x:y:0.01~0.10:0.10~0.50; wherein 0≤x<1, 0≤y<1, and xy = 0; the reaction temperature of the Stille copolymerization reaction is 90~120 °C, preferably 115 °C; the reaction time is 24~72 h, preferably 72 h; the inert atmosphere includes a nitrogen atmosphere or an argon atmosphere; the reaction is carried out in a solvent; the solvent is selected from at least one of toluene and chlorobenzene, preferably chlorobenzene.

[0030] The synthetic route for the polymer shown in formula (I) is shown in [reference]. Figure 1 , Figure 1 This is a schematic diagram of the synthetic route of the polymer shown in formula (I) of this invention.

[0031] The application of the polymer shown in formula (I) above in the fabrication of stretchable organic field-effect transistors.

[0032] A stretchable organic field-effect transistor, wherein the organic semiconductor layer of the organic field-effect transistor is prepared from the polymer shown in formula (I) above; the thickness of the organic semiconductor layer is 10~50 nm.

[0033] Figure 13 This is a schematic diagram of the polymer structure shown in formula (I) of the present invention.

[0034] Example 2 The synthesis of polymer P1-2T (where X is 0.1 and Ar is 2,6-disubstituted pyrrolo[3,4-f]isoindole-1,3,5,7(2H,6H)-tetraone in formula (Ⅰ) is as follows) follows the synthetic route. Figure 1 (As shown).

[0035] 1) Synthesis of tert-butyl (2-(thiophen-2-yl)ethyl)carbamate Take a 250 mL round-bottom flask, protect it with an inert gas atmosphere, add 2-thiopheneethylamine (6.89 g, 54.2 mmol), triethylamine (8.49 g, 8.4 mmol), and anhydrous dichloromethane (130 mL), and stir until fully dissolved at room temperature. Separately, take a 100 mL beaker, add di-tert-butyl dicarbonate (14.2 g, 65.1 mmol), add approximately 30 mL of anhydrous dichloromethane, and stir until fully dissolved. Then, slowly add the di-tert-butyl dicarbonate solution in dichloromethane to the round-bottom flask using a syringe. After the addition is complete, stir the reaction mixture for 72 h. After the reaction is complete, extract the mixture in the flask three times with water and dichloromethane, collect the organic phase, dry it with anhydrous sodium sulfate, filter, remove the solvent using a rotary evaporator, and purify the remaining mixture by column chromatography to obtain the final product, a colorless oily liquid (10.8 g, yield 87%).

[0036] The product characterization data are as follows: Hydrogen spectrum: 1 H NMR (400 MHz, CDCl3): δ (ppm) 7.07 (d, J = 5.1 Hz, 1H), 6.87 (dd, J = 5.0, 3.5 Hz, 1H), 6.77 (d, J = 3.3 Hz, 1H), 5.13 (s, 1H), 3.33 (dd,J = 12.7, 6.3 Hz, 2H), 2.95 (t, J = 6.9 Hz, 2H), 1.41 (s, 9H).

[0037] Carbon spectrum: 13 C NMR (101 MHz, CDCl3): δ (ppm) 155.81, 141.42, 126.94, 125.20, 123.74, 79.18, 42.01, 30.38, 28.40.

[0038] Mass spectrometry: ESI-MS m / z: 250.0 [M+Na] + .

[0039] 2) Synthesis of tert-butyl 2-(5-bromothiophene-2-yl)ethylcarbamate In a 100 mL round-bottom flask under inert gas protection, add the synthesized compound tert-butyl(2-(thiophen-2-yl)ethyl)carbamate (4.09 g, 18 mmol) and DMF (20 mL), and stir until fully dissolved. At room temperature, add NBS (3.56 g, 20 mmol), and then stir overnight at room temperature. After the reaction is complete, extract the mixture three times with water and dichloromethane. Collect the organic phase, dry it with anhydrous sodium sulfate, filter, remove excess solvent using a rotary evaporator, and further purify the remaining mixture by column chromatography to obtain the final product, a brown oily liquid (4.8 g, 87% yield). The product characterization data are as follows: Hydrogen spectrum: 1 H NMR (400 MHz, CDCl3): δ (ppm) 6.80 (d, J = 3.7 Hz, 1H), 6.53 (d, J = 3.6 Hz, 1H), 5.03 (s, 1H), 3.28 (dd, J = 12.4, 6.1 Hz, 2H), 2.88 (t,J = 6.7 Hz, 2H), 1.39 (s, 9H).

[0040] Carbon spectrum: 13 C NMR (75 MHz, CDCl3): δ (ppm) 155.76, 143.24, 129.65, 125.68, 109.61, 79.29, 41.66, 30.76, 28.36.

[0041] Mass spectrometry: ESI-MS m / z: 329.9 [M+2H+Na] + .

[0042] 3) Synthesis of 2-(5-bromothiophene-2-yl)ethylamine Take a 100 mL round-bottom flask, protect it with an inert gas, add the above-synthesized compound tert-butyl(2-(thiophen-2-yl)ethyl)carbamate (3.06 g, 10 mmol) and 1,4-dioxane (25 mL), stir until fully dissolved, add hydroiodic acid (10 mL, 55-57% aqueous solution) at room temperature, and then stir at room temperature for 3 h. After the reaction is complete, pour the mixture into concentrated sodium hydroxide solution to quench the reaction, extract three times with dichloromethane, take the organic phase, dry it with anhydrous sodium sulfate, filter, remove the solvent with a rotary evaporator, and further purify the remaining mixture by column chromatography to obtain the final product, which is a dark brown oily liquid (1.2 g, yield 58%).

[0043] The product characterization data are as follows: Hydrogen spectrum: 1 H NMR (400 MHz, CDCl3) δ (ppm) 6.86 (d, J = 3.6 Hz, 1H), 6.59 (d, J = 3.6 Hz, 1H), 2.99-2.83 (m, 4H), 1.73 (s, 2H).

[0044] Carbon spectrum: 13 C NMR (101 MHz, CDCl3) δ (ppm) 143.88, 129.21, 125.14, 108.97, 42.85, 34.06.

[0045] Mass spectrometry: ESI-MS m / z: 207.9 [M] + .

[0046] 4) Synthesis of 2,6-bis(2-(5-bromothiophen-2-yl)ethyl)pyrrolo[3,4-f]isoindole-1,3,5,7(2H,6H)-tetraone Take a 100 mL round-bottom flask, protect it with an inert gas atmosphere, add the synthesized 2-(5-bromothiophene-2-yl)ethylamine (1.61 g, 7.8 mmol), 1H,3H-benzo[1,2-c:4,5-c']difuran-1,3,5,7-tetraone (1 g, 3.73 mmol), and glacial acetic acid (100 mL), and heat under reflux overnight with stirring. After the reaction is complete, cool to room temperature, extract the mixture three times with water and dichloromethane, collect the organic phase, dry it with anhydrous sodium sulfate, filter, remove the solvent by rotary evaporation, and further purify the residue by column chromatography to obtain the final product as a yellow solid (1.2 g, yield 50%).

[0047] The product characterization data are as follows: Hydrogen spectrum: 1 H NMR (300 MHz, CDCl3) δ 8.26 (d, J = 3.1 Hz, 2H), 6.84 (d, J =3.7 Hz, 2H), 6.62 (d, J = 3.7 Hz, 2H), 3.99 (t, J = 7.2 Hz, 4H), 3.18 (t, J =7.2 Hz, 4H).

[0048] Carbon spectrum: 13C NMR (101 MHz, CDCl3) δ 165.98, 141.23, 137.26, 130.02, 126.46, 118.68, 110.46, 39.69, 29.84, 28.76.

[0049] Mass spectrometry: MALDI-TOF-MS Theoretical value: 594.29; Actual value: 590.87.

[0050] 5) Synthesis of polymer P1-2T Compound (3E,7E)-3,7-bis(6-bromo-1-(4-octadecyltemonodialkyl)-2-oxo-1,2-dihydro-3H-pyrrolo[2,3-b]pyridin-3-ylidene)-3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (77.9 mg, 0.045 mmol), 5,5'-bis(trimethylstanyl)-2,2'-bisthiophene (24.6 mg, 0.05 mmol), and the above-prepared 2,6-bis(2-(5-bromothiophene-2-yl)ethyl)pyrrolo[3,4-f]isoindole-1,3,5,7(2H,6H)-tetraone (2.97 mg, 0.005 mmol), palladium catalyst Pd2(dba)3 (1.5 mg, 0.00164 mg) were added. 0.0148 mmol) of ligand P(o-tol)3 (4.5 mg, 0.0148 mmol) and chlorobenzene (5.0 mL) were added to the reaction flask. After low-temperature deoxygenation under argon atmosphere, the mixture was heated to 115 °C under argon protection for polymerization for 72 h. After cooling, 200 mL of a methanol / 6 M HCl mixture (volume ratio 20:1) was added, and the mixture was stirred at room temperature for 2 h and then filtered. The obtained solid was purified by Soxhlet extraction, with extraction solvents of methanol, acetone, and n-hexane for 12 h each, followed by extraction with chlorobenzene to obtain the target polymer (i.e., Figure 1 The polymer P1-2T with the structure shown was 97 mg, with a yield of 87%.

[0051] The structural characterization data are as follows: Molecular weight: GPC: M n = 50.2 kDa, PDI = 1.81; Elemental analysis: C 1038 H 1566 N 38 O 58 S 22 Calculated values: C, 76.90; H, 9.74; N, 3.28; Actual values: C, 74.79; H, 9.52; N, 3.14; The above indicates that the compound has the correct structure and is a polymer P1-2T.

[0052] Example 3 The synthesis of polymer P2-2T (where X is 0.1 and Ar is 2,7-disubstituted benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone in formula (Ⅰ) is shown in the following synthetic route. Figure 1 (As shown) The synthesis of compounds tert-butyl(2-(thiophen-2-yl)ethyl)carbamate, tert-butyl 2-(5-bromothiophen-2-yl)ethylcarbamate, and 2-(5-bromothiophen-2-yl)ethylamine follows the same synthetic route as in Example 2.

[0053] 1) Synthesis of compound 2,7-bis(2-(5-bromothiophene-2-yl)ethyl)benzo[1mn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone Take a 100 mL round-bottom flask, protect it with an inert gas atmosphere, add the synthesized 2-(5-bromothiophene-2-yl)ethylamine (0.866 g, 4.2 mmol), 1,4,5,8-naphthalenetetracarboxylic anhydride (0.436 g, 2 mmol), and glacial acetic acid (100 mL), and heat under reflux overnight with stirring. After the reaction is complete, cool to room temperature, extract the mixture three times with water and dichloromethane, collect the organic phase, dry it with anhydrous sodium sulfate, filter, remove the solvent by rotary evaporation, and further purify the residue by column chromatography to obtain the final product, a light brown solid (737 mg, yield 62%).

[0054] The structural characterization data are as follows: Hydrogen spectrum: 1 H NMR (300 MHz, CDCl3) δ 8.83 (s, 4H), 6.86 (d, J = 3.6 Hz, 2H), 6.71-6.67 (m, 2H), 4.45 (dd, J = 7.4, 4.5 Hz, 4H), 3.21 (t, J = 7.5 Hz, 4H).

[0055] Mass spectrometry: MALDI-TOF-MS; Theoretical value: 644.35; Actual value: 642.90. 2) Synthesis of polymer P2-2T The compound (3E,7E)-3,7-bis(6-bromo-1-(4-octadecylteicosyl)-2-oxo-1,2-dihydro-3H-pyrrolo[2,3-b]pyridin-3-ylidene)-3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (77.9 mg, 0.045 mmol), 5,5'-bis(trimethyltinyl)-2,2'-bisthiophene (24.6 mg, 0.05 mmol), and the above-prepared 2,7-bis(2-(5-bromothiophene-2-yl)ethyl)benzo[1mn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone (3.22 mg, 0.005 mmol), palladium catalyst Pd2(dba)3 (1.5 mg, 0.00164 mmol), ligand P(o-tol)3 (4.5 mg, 0.0148 mmol), and chlorobenzene (5.0 mL) were added to the reaction flask. After low-temperature deoxygenation under argon atmosphere, the mixture was heated to 115 °C under argon protection for polymerization for 72 h. After cooling, 200 mL of a methanol / 6 M HCl mixture (volume ratio 20:1) was added, and the mixture was stirred at room temperature for 2 h, followed by filtration. The obtained solid was purified by Soxhlet extraction, with extraction solvents of methanol, acetone, and n-hexane for 12 h each, followed by extraction with chlorobenzene to obtain the target polymer (i.e., Figure 1 The polymer P2-2T with the structure shown was 99 mg, with a yield of 93%.

[0056] The structural characterization data are as follows: Molecular weight: GPC: M n = 58.8 kDa, PDI = 2.12; Elemental analysis: C 1042 H 1568 N 38 O 58 S 22 Calculated values: C, 76.96; H, 9.72; N, 3.27; Actual values: C, 76.00; H, 9.60; N, 3.18; The above indicates that the compound has the correct structure and is a polymer P2-2T.

[0057] Example 4 The synthesis of polymer P0-2T (where X is 0 in formula (Ⅰ)) is as follows: Figure 1 (As shown) Compounds (3E,7E)-3,7-bis(6-bromo-1-(4-octadecylteicosyl)-2-oxo-1,2-dihydro-3H-pyrrolo[2,3-b]pyridin-3-ylidene)-3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (86.5 mg, 0.05 mmol), 5,5'-bis(trimethyltinyl)-2,2'-bisthiophene (24.6 mg, 0.05 mmol), palladium catalyst Pd2(dba)3 (1.5 mg, 0.00164 mmol), ligand P(o-tol)3 (4.5 mg, 0.0148 mmol), and chlorobenzene (5.0 mL) were added to a reaction flask. After low-temperature deoxygenation under argon atmosphere, the mixture was heated to 115 °C under argon protection for polymerization reaction for 72 h. After cooling, 200 mL of a methanol / 6 M HCl mixture (volume ratio 20:1) was added, and the mixture was stirred at room temperature for 2 h, followed by filtration. The obtained solid was purified by Soxhlet extraction, with extraction solvents of methanol, acetone, and n-hexane for 12 h each, followed by extraction with chlorobenzene to obtain the target polymer (i.e., Figure 1 The polymer P0-2T with the structure shown was 97 mg, with a yield of 87%.

[0058] The structural characterization data are as follows: Molecular weight: GPC: M n = 149.8 kDa, PDI = 2.76; Elemental analysis: C 112 H 172 N4O6S2, calculated values: C, 77.55; H, 9.99; N, 3.23; actual values: C, 74.20; H, 9.60; N, 3.02; The above indicates that the compound has the correct structure and is a polymer P0-2T.

[0059] Example 5 Spectroscopic properties of polymers P0-2T, P1-2T and P2-2T Figure 2 This is a schematic diagram of the ultraviolet-visible absorption spectra of polymers P0-2T, P1-2T and P2-2T in chlorobenzene solution in the embodiments of the present invention, where Absorbance (au) represents the normalized absorption intensity; Wavelength (nm) represents the wavelength (nanometer).

[0060] Figure 3This is a schematic diagram of the ultraviolet-visible absorption spectra of polymer P0-2T, P1-2T and P2-2T films in the embodiments of the present invention, where Absorbance (au) represents the normalized absorption intensity; Wavelength (nm) represents the wavelength (nanometer).

[0061] Depend on Figure 2 It is known that the polymer of the present invention has strong absorption in both the short wavelength range (300~500 nm) and the long wavelength range (600~1000 nm), which correspond to π-π* transition and intramolecular charge transfer effect, respectively. Moreover, the intramolecular charge transfer effect is very strong, indicating that there is a strong intermolecular interaction between the donor and acceptor in the polymer molecule of the present invention.

[0062] Depend on Figure 3 It is evident that the polymer of this invention exhibits strong ordered aggregation in the thin film. This strong ordered aggregation of molecules helps the polymer molecules form a more ordered arrangement, thereby facilitating carrier transport. On the other hand, the introduction of different flexible units significantly alters the intensity of the shoulder peak in the long wavelength range, indicating that the introduction of flexible units has a certain impact on polymer absorption and thin film aggregation.

[0063] Example 6 Thermal properties of polymers P0-2T, P1-2T and P2-2T Figure 4 This is a schematic diagram of the thermogravimetric analysis curves of polymers P0-2T, P1-2T, and P2-2T described in the embodiments of the present invention, where Weight (wt %) represents the mass percentage; Temperature (°C) represents the temperature (degrees Celsius).

[0064] Depend on Figure 4 It is known that the decomposition temperatures (5% loss) of the polymers P0-2T, P1-2T and P2-2T of the present invention are all between 450 and 470°C, indicating that the polymers of the present invention have good thermal stability.

[0065] Figure 5 , Figure 6 , Figure 7 These are schematic diagrams of differential scanning calorimetry (DSC) curves of polymers P0-2T, P1-2T, and P2-2T described in the embodiments of the present invention. Heat Flow (W / g) represents the difference in heat flow rate (W / g) between the sample and the reference (an empty crucible) during the test; Temperature (°C) represents the temperature (degrees Celsius), and the reference used is an empty crucible.

[0066] Depend on Figure 5 , Figure 6 and Figure 7It is known that the polymer of the present invention does not exhibit glass transition phenomenon within the differential scanning test range (50~250 °C).

[0067] comprehensive Figure 4-7 It is known that the polymer of the present invention has good thermal stability and can be annealed at a certain temperature to optimize the performance of the final device.

[0068] Example 7 Electrical properties of polymers P0-2T, P1-2T and P2-2T Figure 8 This is a schematic diagram of the cyclic voltammetry curves of polymers P0-2T, P1-2T, and P2-2T described in the embodiments of the present invention, where Potential (V) represents the potential (volts) of the working electrode during the test; Current (A) represents the current (amperes) of the working electrode during the test; a calomel electrode is used as the reference electrode, and a platinum wire is used as the counter electrode.

[0069] Depend on Figure 8 It is known that the polymers P0-2T, P1-2T, and P2-2T of the present invention have low HOMO and LUMO energy levels (HOMO energy level below -5.8 eV, LUMO energy level below -3.5 eV). Among them, the lower HOMO energy level helps to suppress hole transport, while the lower LUMO energy level helps to promote electron transport. The introduction of different flexible units has little effect on the polymer energy levels.

[0070] Example 8 Characterization of the molecular arrangement of polymers P0-2T, P1-2T and P2-2T in thin films.

[0071] Figure 9 This is a schematic diagram of the two-dimensional grazing-incident X-ray diffraction (2D-GIWAX) patterns of the polymers P0-2T, P1-2T, and P2-2T in the embodiments of the present invention; wherein, the upper figure is the film pattern before annealing, and the lower figure is the film pattern after annealing, with the horizontal axis q xy (A -1 () represents the combined component (angstroms) of the scattered wave vector within the sample surface. -1 y-coordinate q z (A -1 The denoted represents the composite component (angstroms) of the scattered wave vector outside the sample surface. -1 .

[0072] Depend on Figure 9It can be seen that the molecules of the thin film mainly adopt an edge-on molecular arrangement, and all three polymers have good crystallinity. After annealing, the crystallinity and order of the film are further improved. The introduction of flexible segments has little impact on the molecular arrangement and stacking of the polymers, while good molecular arrangement of the thin film is beneficial to the transport of charge carriers.

[0073] Example 9 Preparation and properties of stretchable OFETs of polymers P0-2T, P1-2T and P2-2T.

[0074] Figure 10 , Figure 11 , Figure 12 The figures show schematic diagrams (A) and (B) of the transfer characteristic curves of stretchable OFETs based on P0-2T, P1-2T, and P2-2T using representative polymers provided by this invention; wherein, |I DS | 1 / 2 (A) 1 / 2 Represents |current| 1 / 2 (ampere) 1 / 2 V GS (V) represents the grid voltage (volts); I DS (A) represents current (amperes); V DS (V) represents the source-drain voltage (volts), and the device uses a top-gate-bottom contact structure.

[0075] Depend on Figure 10 , Figure 11 and Figure 12 It is evident that the OFETs prepared from the polymer of this invention exhibit excellent electron transport performance. The carrier mobility can be calculated using the following equation: I DS = (W / 2L)C i μ(V G – V TH ) 2 (sat., V DS = V G – V TH ) Among them, I DS V is the drain current, μ is the carrier mobility, and V is the drain current. G V is the gate voltage. TH Where W is the threshold voltage, W is the channel width (1400 μm), L is the channel length (30 μm), and C is the channel width (1400 μm). i It is an insulator capacitor. Utilizing (I) DS , sat) 1 / 2 For V GPlot the graph and perform a linear regression. The carrier mobility can be calculated from the slope of the regression line, and V can be obtained from the intersection of the regression line and the X-axis. TH The average electron mobility is obtained by averaging the electron mobility of multiple devices. The on / off ratio can be obtained by the ratio of the maximum to the minimum source-drain current in the figure.

[0076] More than 12 organic field-effect transistor devices were fabricated using the polymers P0-2T, P1-2T, and P2-2T of this invention as semiconductor layers. These devices exhibited stable performance, and their representative performance parameters are shown in Table 1. In summary, the experimental results show that the flexible stretchable polymer shown in formula (Ⅰ) provided by this invention is an excellent electron transport material.

[0077] This invention is not limited to the reported P0-2T, P1-2T, and P2-2T polymer materials. By changing different substituents R, altering the length of the flexible unit (e.g., increasing or decreasing the number of methylene groups in the middle), and changing the proportion of the flexible monomer added to the polymer (i.e., changing the value of X), a series of novel flexible stretchable polymers can be obtained. Furthermore, the synthetic route provided in this invention is simple and easy to implement, with few synthetic steps, high yield, and suitable for large-scale synthesis. This has important reference value for further research and development of high-performance n-type polymer semiconductor materials and applications such as stretchable field-effect transistors and even electronic skin. The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A polymer, characterized in that, The structural formula of the polymer is shown as formula (I): In formula (I), X is 0 or 0.1, Ar is a disubstituted aromatic ring imide group, and n is 5-200.

2. The polymer of claim 1, wherein In formula (I), Ar is 2,6-disubstituted pyrrolo[3,4-f]isoindole-1,3,5,7(2H,6H)-tetrone or 2,7-disubstituted benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone.

3. A preparation method of the polymer shown as formula (I) according to any one of claims 1 or 2, the preparation method comprising the following steps: S1, in an inert atmosphere, 2-thiopheneethylamine and triethylamine are dissolved in an organic solvent, and di-tert-butyl dicarbonate is slowly added and stirred until the reaction is complete, to obtain a S1 reaction solution, which is extracted, dried, and purified by column chromatography to obtain an intermediate shown as formula (II), wherein Boc is a tert-butyl carbonate group in formula (II); S2, in an inert atmosphere, the intermediate shown as formula (II) is dissolved in an organic solvent, and N-bromosuccinimide (NBS) is added and stirred until the reaction is complete, to obtain a S2 reaction solution, which is extracted, dried, and purified by column chromatography to obtain an intermediate shown as formula (III), wherein Boc is a tert-butyl carbonate group in formula (III); S3, in an inert atmosphere, the intermediate shown as formula (III) is dissolved in an organic solvent, and hydroiodic acid solution is added and stirred until the reaction is complete, to obtain a S3 reaction solution, which is extracted, dried, and purified by column chromatography to obtain an intermediate shown as formula (IV); S4, in an inert atmosphere, the intermediate shown as formula (IV) is dissolved in glacial acetic acid, and 1H,3H-benzo[1,2-c:4,5-c']difuran-1,3,5,7-tetrone is added and stirred and heated to reflux overnight, and after the reaction is complete, a S4 reaction solution is obtained, which is extracted, dried, and purified by column chromatography to obtain a flexible monomer shown as formula (V); S5, in an inert atmosphere, the intermediate shown as formula (IV) is dissolved in glacial acetic acid, and 1,4,5,8-naphthalenetetracarboxylic anhydride is added and stirred and heated to reflux overnight, and after the reaction is complete, a S5 reaction solution is obtained, which is extracted, dried, and purified by column chromatography to obtain a flexible monomer shown as formula (VI); S6, in an inert atmosphere, under the catalysis of a palladium catalyst and a phosphine ligand, a Stille copolymerization reaction is carried out on a compound shown as formula (VII), a compound shown as formula (VIII), the flexible monomer shown as formula (V), and the flexible monomer shown as formula (VI) according to a certain molar ratio, to obtain the polymer shown as formula (I) 。 4. The production method according to claim 3, characterized by, The organic solvent in step S1 is anhydrous dichloromethane, and the concentration of 2-thiopheneethylamine in the organic solvent is 0.2-1 mol / L; The molar ratio of the 2-thiopheneethylamine, triethylamine, and di-tert-butyl dicarbonate is 1:1.2-2:1.1-1.5; The reaction time in step S1 is 72-96 h.

5. The preparation method according to claim 3, characterized in that, The organic solvent in step S2 is N,N-dimethylformamide (DMF), and the concentration of the intermediate represented by formula (II) in the organic solvent is 0.5-1 mol / L; The molar ratio of the intermediate represented by formula (II) to the NBS is 1:1-1.

2.

6. The preparation method according to claim 3, characterized in that, The organic solvent in step S3 is 1,4-dioxane, and the concentration of the intermediate represented by formula (III) in the organic solvent is 0.2-0.5 mol / L; The volume ratio of the 1,4-dioxane solution of the intermediate represented by formula (III) to the hydriodic acid solution is 2-3:1, and the hydriodic acid is a 55-57% mass fraction aqueous solution.

7. The preparation method according to claim 3, characterized in that, The concentration of the intermediate represented by formula (IV) in the glacial acetic acid in steps S4 and S5 is 0.01-0.1 mol / L; The molar ratio of the intermediate represented by formula (IV) to 1,4,5,8-naphthalenetetracarboxylic anhydride in step S5 is 2-2.2:

1.

8. The preparation method according to claim 3, characterized in that, In step S6, the palladium catalyst is selected from at least one of tetrakis(triphenylphosphine)palladium and tris(dibenzylideneacetone)dipalladium; The molar ratio of the compounds represented by formula (VII), formula (VIII), formula (V), formula (VI), the palladium catalyst and the phosphine ligand is (1-x-y):1:x:y:0.01-0.10:0.10-0.50; wherein 0≤x<1, 0≤y<1 and xy = 0; The reaction temperature of the copolymerization reaction is 90-120 ℃, and the inert atmosphere includes a nitrogen atmosphere or an argon atmosphere.

9. Use of the polymer represented by formula (I) according to any one of claims 1-2 in the preparation of a stretchable organic field effect transistor.

10. A stretchable organic field effect transistor, characterized by, The organic semiconductor layer of the organic field effect transistor is prepared from the polymer represented by formula (I) according to any one of claims 1-2; The thickness of the organic semiconductor layer is 10-50 nm.

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