Receptor unit based on oxygen-boron-nitrogen coordination, n-type polymer and preparation and application thereof

Abstract

The invention relates to the technical field of organic polymers and organic photoelectric materials, in particular to an acceptor unit based on oxygen-boron-nitrogen coordination, an n-type polymer and preparation and application thereof. According to the invention, a receptor unit with strong electron-withdrawing characteristic is prepared through a Schiff base boron-nitrogen coordination reaction, a bromination reaction and a coupling reaction, and the conjugated polymer with lower LUMO energy level is prepared through a polymerization reaction. Furthermore, the polymer is used as an organic semiconductor layer to prepare an organic field effect transistor and an organic thermoelectric material with relatively high electron mobility and power factor. According to the invention, efficient synthesis of electron-deficient acceptors and preparation of high-electron-mobility polymers are realized, application of n-type polymer semiconductor materials in the fields of flexibility, printing and wearable electronics is promoted, and the method has important significance in industrialization of organic photoelectric devices.

Description

Technical Field

[0001] The invention relates to the technical field of organic polymers and organic photoelectric materials, and in particular to an oxygen-boron-nitrogen coordination-based receptor unit, an n-type polymer, and preparation and application thereof. Background Art

[0002] Conjugated polymers have the advantages of light weight, low cost, good flexibility and solution processing. They have been widely studied in various optoelectronic device fields such as organic light-emitting diodes, organic field-effect transistors, organic photovoltaic cells and organic hotspot materials. Among them, organic field-effect transistors prepared with conjugated polymers as organic semiconductor layers have important applications in logic circuits, flexible displays, sensor arrays and wearable devices, and have attracted great attention from academia and industry. As the core component of organic field-effect transistors, organic semiconductor layers can be divided into three categories according to the type of carrier transport: hole transport (p-type), ambipolar transport (ambipolar) and electron transport (n-type). In recent years, p-type and ambipolar polymer semiconductors have developed rapidly. For example, the hole mobility of p-type polymer semiconductors is as high as 30cm 2 V -1 s -1 The bipolar polymers exhibit balanced transport properties with hole and electron mobilities exceeding 3 cm 2 V -1 s -1 In contrast, the performance of n-type polymers still lags behind, with electron mobility (μ e ) is usually less than 3cm 2 V -1 s -1 High-performance n-type polymers are of great significance for the development of organic electronic devices based on pn junctions (including all-polymer solar cells and polymer thermoelectric devices), logic complementary circuits, reducing device power consumption, improving signal-to-noise ratio, and improving anti-interference capabilities. Therefore, the development of high-performance n-type polymer semiconductors is crucial to the development of the field of organic electronics.

[0003] The construction of high-performance n-type polymers usually requires acceptor units with compact molecular structures and strong electron-withdrawing properties to achieve the lowest unoccupied molecular orbital (LUMO) energy level of the conjugated polymer <-4.00 eV, thereby promoting electron injection and air stability. In order to obtain a deeper LUMO energy level, strong electron-withdrawing groups are usually introduced into the polymer backbone to form copolymers, which is a major approach to obtain high-performance n-type polymer semiconductor materials. At present, four types of acceptors with prominent electron-withdrawing groups (EWG) are commonly used to modify the polymer backbone: imide (e.g., naphthalene diimide, dithiophene imide), amide (e.g., isoindigo, pyrrolopyrrole dione), boron nitrogen coordination bond, and cyano functionalized building blocks. However, a single type of electron-withdrawing group usually has a high LUMO energy level, which is not conducive to the effective injection and output of electrons. Therefore, how to develop acceptor units with strong electron-withdrawing properties to effectively reduce the LUMO energy level of the polymer and improve the electron mobility of the conjugated polymer is an important issue that needs to be solved urgently. Summary of the invention

[0004] In order to solve the above problems, the purpose of the present invention is to provide an acceptor unit based on oxygen-boron-nitrogen coordination, an n-type polymer, and its preparation and application. The present invention solves the problem of low electron mobility of current n-type polymer semiconductor materials by developing conjugated polymers with low LUMO energy levels, and successfully applies the prepared n-type polymer semiconductor materials to organic semiconductor devices.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] The first object of the present invention is to provide an oxygen-boron-nitrogen coordination-based receptor unit, the chemical structure of which is shown in the following formula (I):

[0007]

[0008] In formula (I), m1 and m2 are independently 0 or 1; x1, x2, y1 and y2 are independently any integer from 1 to 20; R is a fluorine atom or a cyano group; Ar is one of the following structures:

[0009]

[0010] Wherein, X1, X2, X3 and X4 are independently selected from one of methyl, ethyl, isopropyl, methoxy, fluorine or chlorine, and Y1 and Y2 are independently selected from one of nitrogen or hydrogen.

[0011] In one embodiment of the present invention, the oxygen-boron-nitrogen coordination-based acceptor unit is selected from one of the following structural formulas:

[0012]

[0013] The second object of the present invention is to provide a method for preparing an oxygen-boron-nitrogen coordinated receptor unit, comprising the following steps:

[0014] (S1) placing 2,5-dihydroxy-1,4-benzenedicarbaldehyde and an alkylamine in a first solvent to perform an imine condensation reaction to obtain a Schiff base intermediate;

[0015] (S2) placing the Schiff base intermediate prepared in step (S1), N-diisopropylethylamine and boron trifluoride ether complex in a second solvent, and obtaining 3,8-bis(alkyl)-tetrafluoro-benzobis([1,3,2]oxazoline) through a Schiff base boron-nitrogen coordination reaction;

[0016] (S3) placing the 3,8-bis(alkyl)-tetrafluoro-benzobis([1,3,2]oxazoline) prepared in step (S2) and liquid bromine in a third solvent, catalyzed by a first catalyst, and performing a bromination reaction to obtain 3,8-bis(alkyl)-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline);

[0017] (S4) placing the 3,8-bis(alkyl)-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline) and aryltin prepared in step (S3) in a fourth solvent, catalyzed by a second catalyst, and performing a coupling reaction to obtain a first receptor unit;

[0018] Or, (S5) placing the first receptor unit prepared in step (S4), tin tetrachloride and trimethylsilyl cyanide in a fifth solvent to obtain a second receptor unit after reaction;

[0019] The receptor unit based on oxygen-boron-nitrogen coordination is the first receptor unit or the second receptor unit;

[0020] Wherein, the chemical structural formula of the first receptor unit is shown in formula (II), and the chemical structural formula of the second receptor unit is shown in formula (III);

[0021]

[0022] Wherein, in formula (I) and formula (III), m1 and m2 are independently 0 or 1; x1, x2, y1 and y2 are independently any integer from 1 to 20; Ar is one of the following structures:

[0023]

[0024] Wherein, X1, X2, X3 and X4 are independently selected from one of methyl, ethyl, isopropyl, methoxy, fluorine or chlorine, and Y1 and Y2 are independently selected from one of nitrogen or hydrogen.

[0025] In one embodiment of the present invention, in step (S1), the molar ratio of 2,5-dihydroxy-1,4-benzenedicarbaldehyde to alkylamine is 1:2.1-3;

[0026] During the reaction, the temperature is 60-100°C and the time is 2.5-12h;

[0027] In step (S2), the molar ratio of the Schiff base intermediate, ultra-dry N,N-diisopropylethylamine and ultra-dry boron trifluoride etherate is 1:5-10:5-10;

[0028] During the reaction, the temperature is 25-80°C and the reaction time is 6-24h;

[0029] In step (S3), the molar ratio of 3,8-bis(alkyl)-tetrafluoro-benzobis([1,3,2]oxazoline) to liquid bromine is 1:10-20;

[0030] During the reaction, the temperature is 25-60°C and the reaction time is 4-12 hours.

[0031] In one embodiment of the present invention, the first solvent is selected from one of N,N-dimethylformamide, ethanol or chloroform;

[0032] The second solvent is selected from one of toluene, chloroform or dichloromethane;

[0033] The third solvent is selected from one of dichloromethane or chloroform;

[0034] The first catalyst is FeCl3.

[0035] In one embodiment of the present invention, in step (S4), the molar ratio of 3,8-bis(alkyl)-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline) to aryltin is 1:2-4;

[0036] During the reaction, the temperature is 90-120°C and the reaction time is 12-24 hours.

[0037] In one embodiment of the present invention, in step (S4), the fourth solvent is selected from one of toluene or chlorobenzene;

[0038] The second catalyst is tris dibenzylideneacetone dipalladium;

[0039] A ligand needs to be added during the reaction, wherein the ligand is tri(o-methylphenyl)phosphine.

[0040] In step (S5), the molar ratio of the first receptor unit, tin tetrachloride and trimethylsilyl cyanide is 1:10-20:10-20;

[0041] During the reaction, the temperature is room temperature and the time is 12 to 24 hours.

[0042] In one embodiment of the present invention, the fifth solvent is dichloromethane.

[0043] The third object of the present invention is to provide an application of an oxygen-boron-nitrogen coordination-based acceptor unit in the preparation of an n-type polymer.

[0044] The fourth object of the present invention is to provide an n-type polymer prepared from the above-mentioned receptor unit based on oxygen-boron-nitrogen coordination, wherein the chemical structure of the n-type polymer is shown in formula (V):

[0045]

[0046] Wherein, in formula (V), m1, m2, m3 and m4 are independently 0 or 1; n is an integer greater than 0; x1, x2, x3, x4, y1, y2, y3 and y4 are independently any integer from 1 to 20; R is a fluorine atom or a cyano group; Ar is one of the following structures:

[0047]

[0048] Wherein, X1, X2, X3 and X4 are independently selected from one of methyl, ethyl, isopropyl, methoxy, fluorine or chlorine, and Y1 and Y2 are independently selected from one of nitrogen or hydrogen.

[0049] In one embodiment of the present invention, the oxygen-boron-nitrogen coordination-based acceptor unit is selected from one of the following structural formulas:

[0050]

[0051] n is an integer greater than 0.

[0052] A fifth object of the present invention is to provide a method for preparing an n-type polymer, comprising the following steps:

[0053] (A1) placing an oxygen-boron-nitrogen coordination-based acceptor unit and N-bromosuccinimide in a sixth solvent to react to obtain a bromine-substituted oxygen-boron-nitrogen coordination-based acceptor unit;

[0054] (A2) dissolving the bromine-substituted oxygen-boron-nitrogen coordinated receptor unit prepared in step (A1), alkyl-substituted thienyl pyrrolopyrrole diketotin, tridibenzylideneacetone dipalladium and tri(o-methylphenyl)phosphine in a seventh solvent, and performing post-treatment after the reaction to obtain an n-type polymer.

[0055] In one embodiment of the present invention, in step (A1), the molar ratio of the oxygen-boron-nitrogen coordinated acceptor unit to N-bromosuccinimide is 1:2 to 1:3;

[0056] During the reaction, the temperature is 25-50°C and the reaction time is 2-8h;

[0057] In step (A2), the molar ratio of the bromine-substituted oxygen-boron-nitrogen-coordinated acceptor unit, the alkyl-substituted thienylpyrrolopyrrole diketotin, trisdibenzylideneacetone dipalladium, and tri(o-methylphenyl)phosphine is 1:1:0.05-0.1:0.05-0.1;

[0058] During the reaction, the temperature is 90-110°C and the time is 12-48 hours.

[0059] A sixth object of the present invention is to provide an application of an n-type polymer in preparing an organic field effect transistor or an organic thermoelectric material.

[0060] A seventh object of the present invention is to provide an organic field effect transistor, which is prepared from the n-type polymer according to claim 5.

[0061] In one embodiment of the present invention, the organic field effect transistor is a top gate bottom contact structure, including a substrate with a thickness of 200 to 300 nm, a source and drain electrode with a thickness of 10 to 40 nm, a charge transfer layer with a thickness of 1 to 1000 nm, a dielectric layer with a thickness of 400 to 500 nm, and a gate electrode with a thickness of 50 to 90 nm.

[0062] In one embodiment of the present invention, the substrate is a Si / SiO2 substrate, the source and drain electrodes are made of gold, the dielectric layer is made of PMMA, and the gate electrode is made of gold.

[0063] In one embodiment of the present invention, the electron mobility of the charge transport layer material in the organic field effect transistor is between 3.0 cm 2 V -1 s -1 above.

[0064] An eighth object of the present invention is to provide an organic thermoelectric material, wherein the organic thermoelectric material is prepared from an n-type polymer, wherein the organic thermoelectric material is a semiconductor thin film.

[0065] In one embodiment of the present invention, an organic thermoelectric material is prepared using an n-type polymer and an n-type dopant, wherein the n-type dopant is 4-(2,3-dihydro-1,3-dimethyl-1H-benzimidazol-2-yl)-N,N-diphenylaniline.

[0066] In the present invention, after being doped with n-type polymer, the conductivity of the polymer semiconductor material can reach up to 95.5Scm -1 , the power factor reached 147.8μW m-1 K -2 .

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] (1) The oxygen-boron-nitrogen coordinated acceptor unit of the present invention has the characteristics of good planarity, rigid conjugated skeleton, strong intermolecular π-π interaction and deep LUMO energy level, and can be used to construct n-type polymer semiconductor materials; through n-type doping, this type of n-type polymer semiconductor material can also be used in organic thermoelectric materials.

[0069] (2) The oxygen-boron-nitrogen coordination-based receptor unit provided by the present invention has a short synthesis step, and the total yield from the raw material to the target receptor unit is as high as 38%, which has the advantages of short reaction time and high synthesis efficiency.

[0070] (3) The oxygen-boron-nitrogen coordination-based acceptor units provided by the present invention generally have a lower LUMO energy level (<-3.94 eV), which can be as low as -4.34 eV. The n-type polymer obtained by Stille polymerization based on the above acceptor units also has a lower LUMO energy level (≈-4.0 eV). The lower LUMO energy level is conducive to the injection and output of electrons, thereby improving the electron mobility, so that the electron mobility of the above n-type polymer reaches 3.04 cm 2 V -1 s -1 .

[0071] (3) The n-type polymer provided by the present invention exhibits high electrical conductivity and power factor in organic thermoelectric materials, with the highest electrical conductivity reaching 95.5S cm -1 , the power factor reached 147.8μW m -1 K -2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of 3,8-bis(2-ethylhexyl)-tetrafluoro-benzobis([1,3,2]oxazoline) in Example 1;

[0073] Figure 2 is the hydrogen nuclear magnetic resonance spectrum of 3,8-bis(2-ethylhexyl)-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline) in Example 1;

[0074] Figure 3 is the hydrogen nuclear magnetic resonance spectrum of the fluorinated acceptor unit based on oxygen-boron-nitrogen coordination in Example 1;

[0075] Figure 4is the hydrogen nuclear magnetic resonance spectrum of 3,8-dihexyl-tetrafluoro-benzobis([1,3,2]oxazoline) in Example 2;

[0076] Figure 5 is the hydrogen nuclear magnetic resonance spectrum of 3,8-dihexyl-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline) in Example 2;

[0077] Figure 6 is the hydrogen nuclear magnetic resonance spectrum of the fluorinated acceptor unit based on oxygen-boron-nitrogen coordination in Example 2;

[0078] Figure 7 is the hydrogen nuclear magnetic resonance spectrum of the cyanation acceptor unit based on oxygen-boron-nitrogen coordination in Example 2;

[0079] Figure 8 is the hydrogen nuclear magnetic resonance spectrum of the fluorinated acceptor unit based on oxygen-boron-nitrogen coordination substituted by bromine in Example 3;

[0080] Fig. 9 is the absorption spectrum of the n-type polymer P1 in Example 3;

[0081] Fig.10 is the hydrogen nuclear magnetic resonance spectrum of the cyanation acceptor unit based on oxygen-boron-nitrogen coordination substituted by bromine in Example 4;

[0082] Fig.11 This is the absorption spectrum of the n-type polymer P2 in Example 4. DETAILED DESCRIPTION

[0083] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0084] In the following examples, unless otherwise specified, all reagents used are commercially available reagents, and all detection means and methods used are conventional detection means and methods in the art.

[0085] Example 1

[0086] This embodiment provides a method for preparing an oxygen-boron-nitrogen coordinated receptor unit, which specifically comprises the following steps:

[0087] (S1) 2,5-dihydroxy-1,4-benzenedicarboxylic acid (1 g, 6 mmol) and 2-ethylhexylamine (2.33 g, 2.96 mL, 18 mmol) were used as the reaction materials (the molar ratio of 2,5-dihydroxy-1,4-benzenedicarboxylic acid to 2-ethylhexylamine was 1:3), and placed in 50 mL of ethanol for imine condensation reaction (reaction temperature was 100 ° C, reaction time was 6 h). After the reaction was completed, the mixture was diluted with dichloromethane, and then dried over anhydrous magnesium sulfate, filtered, and concentrated in vacuo to obtain a Schiff base intermediate;

[0088] (S2) The Schiff base intermediate prepared in step (S1) and ultra-dried N, N-diisopropylethylamine (3.88 g, 5.23 mL, 30 mmol) and ultra-dried boron trifluoride etherate (4.26 g, 7.71 mL, 30 mmol) were used as reaction raw materials (the molar ratio of the Schiff base intermediate, ultra-dried N, N-diisopropylethylamine and ultra-dried boron trifluoride etherate was 1:5:5), and placed in 100 mL of dichloromethane for Schiff base boron nitrogen coordination reaction (reaction temperature was 50°C, reaction time was 12 h). After the reaction, the crude product was further purified by silica gel column using dichloromethane and petroleum ether as eluents (the volume ratio of dichloromethane to petroleum ether was 1:1) to obtain 1.72 g 3,8-bis(2-ethylhexyl)-tetrafluoro-benzobis([1,3,2]oxazoline) (H NMR spectrum as shown in FIG. Figure 1 As shown), the yield is 60% (the yield from step (S1) to step (S2) is 60%);

[0089] The chemical structure of 3,8-bis(2-ethylhexyl)-tetrafluoro-benzobis([1,3,2]oxazoline) is as follows:

[0090]

[0091] (S3) 3,8-bis(2-ethylhexyl)-tetrafluoro-benzobis([1,3,2]oxazoline) (2.42 g, 5 mmol) prepared in step (S2) and liquid bromine (15.98 g, 5.14 mL, 100 mmol) were used as reaction raw materials (the molar ratio of 3,8-bis(2-ethylhexyl)-tetrafluoro-benzobis([1,3,2]oxazoline) to liquid bromine was 1:20), placed in 50 mL of chloroform for bromination reaction (with 10 mg FeCl3 as catalyst, reaction temperature of 60°C, reaction time of 4 h), after the reaction was completed, the crude product was further purified by silica gel column using dichloromethane and petroleum ether as eluents (the volume ratio of dichloromethane to petroleum ether was 1:1) to obtain 2.89 g 3,8-Bis(2-ethylhexyl)-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline) (H NMR spectrum Figure 2 As shown), the yield is 90%;

[0092] The chemical structure of 3,8-bis(2-ethylhexyl)-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline) is as follows:

[0093]

[0094] (S4) 3,8-bis(2-ethylhexyl)-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline) (642 mg, 1 mmol) and tributyl(2-thienyl)tin (9.33 mg, 2.5 mmol) prepared in step (S3) were used as reaction raw materials (the molar ratio of 3,8-bis(2-ethylhexyl)-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline) to tributyl(2-thienyl)tin was 1: 2.5), placed in toluene for coupling reaction (tridibenzylideneacetone dipalladium (91.5 mg, 1 mmol) as catalyst, tri(o-methylphenyl)phosphine (60.8 mg, 2 mmol) as ligand, reaction temperature 110°C, reaction time 12 h), after the reaction, the crude product was further purified by silica gel column using ethyl acetate and petroleum ether as eluents (the volume ratio of ethyl acetate to petroleum ether was 1:4), with a yield of 90%, to obtain 583 mg 3,8-bis(2-ethylhexyl)-tetrafluoro-5,10-di(thiophen-2-yl)-benzobis([1,3,2]oxazoline), i.e., an oxygen-boron-nitrogen-coordinated receptor unit: an oxygen-boron-nitrogen-coordinated fluorinated receptor unit (H NMR spectrum as shown in FIG. Figure 3 shown);

[0095] The chemical structure of the fluorinated acceptor unit based on oxygen-boron-nitrogen coordination is shown below:

[0096]

[0097] Example 2

[0098] This embodiment provides a method for preparing an oxygen-boron-nitrogen coordinated receptor unit, which specifically comprises the following steps:

[0099] (S1) 2,5-dihydroxy-1,4-benzenedicarbaldehyde (1 g, 6 mmol) and n-hexylamine (1.8 g, 2.34 mL, 18 mmol) were used as the reaction materials (the molar ratio of 2,5-dihydroxy-1,4-benzenedicarbaldehyde to n-hexylamine was 1:3), placed in 50 mL of ethanol for imine condensation reaction (reaction temperature was 100 ° C, reaction time was 6 h), and after the reaction was completed, the mixture was diluted with dichloromethane, and then dried over anhydrous magnesium sulfate, filtered, and concentrated in vacuo to obtain a Schiff base intermediate;

[0100] (S2) The Schiff base intermediate prepared in step (S1) and ultra-dried N, N-diisopropylethylamine (3.88 g, 5.23 mL, 30 mmol) and ultra-dried boron trifluoride etherate (4.26 g, 7.71 mL, 30 mmol) were used as reaction raw materials (the molar ratio of the Schiff base intermediate, ultra-dried N, N-diisopropylethylamine and ultra-dried boron trifluoride etherate was 1:5:5), and placed in 100 mL of dichloromethane for Schiff base boron nitrogen coordination reaction (reaction temperature was 50°C, reaction time was 12 h). After the reaction, the crude product was further purified by silica gel column using dichloromethane and petroleum ether as eluents (the volume ratio of dichloromethane to petroleum ether was 1:1) to obtain 1.54 g 3,8-dihexyl-tetrafluoro-benzobis([1,3,2]oxazoline) (H NMR spectrum was as follows: Figure 4 As shown), the yield is 60% (the yield from step (S1) to step (S2) is 60%);

[0101] The chemical structure of 3,8-dihexyl-tetrafluoro-benzobis([1,3,2]oxazoline) is as follows:

[0102]

[0103] (S3) The 3,8-dihexyl-tetrafluoro-benzobis([1,3,2]oxazoline) (2.14 g, 5 mmol) prepared in step (S2) and liquid bromine (15.98 g, 5.14 mL, 100 mmol) were used as reaction raw materials (the molar ratio of 3,8-di(hexyl)-tetrafluoro-benzobis([1,3,2]oxazoline) to liquid bromine was 1:20), placed in 50 mL of chloroform for bromination reaction (with 10 mg FeCl3 as catalyst, reaction temperature of 60°C, reaction time of 4 h), and after the reaction, the crude product was further purified by silica gel column using dichloromethane and petroleum ether as eluents (the volume ratio of dichloromethane to petroleum ether was 1:1) to obtain 5.64 g 3,8-dihexyl-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline) (H NMR spectrum as shown in Figure 5 As shown), the yield is 90%;

[0104] The chemical structure of 3,8-dihexyl-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline) is as follows:

[0105]

[0106] (S4) 3,8-dihexyl-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline) (586 mg, 1 mmol) and tributyl(2-thienyl)tin (9.33 mg, 2.5 mmol) prepared in step (S3) were used as reaction raw materials (the molar ratio of 3,8-dihexyl-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline) to tributyl(2-thienyl)tin was 1:2.5), and placed in toluene for coupling reaction (tridibenzylideneacetone dipalladium (91.5 mg, 1 mmol) was used as catalyst) , tri(o-methylphenyl)phosphine (60.8 mg, 2 mmol) was used as a ligand, the reaction temperature was 110°C, and the reaction time was 12 h. After the reaction, the crude product was further purified by a silica gel column using ethyl acetate and petroleum ether as eluents (the volume ratio of ethyl acetate to petroleum ether was 1:4), and the yield was 90%, to obtain 583 mg of 3,8-dihexyl-tetrafluoro-5,10-di(thiophen-2-yl)-benzobis([1,3,2]oxazoline), i.e., an oxygen-boron-nitrogen-coordinated receptor unit: an oxygen-boron-nitrogen-coordinated fluorinated receptor unit (H NMR spectrum as shown in FIG. Figure 6 shown);

[0107] The chemical structure of the fluorinated acceptor unit based on oxygen-boron-nitrogen coordination is shown below:

[0108]

[0109] (S5) Using the fluorinated acceptor unit based on oxygen-boron-nitrogen coordination (1.18 g, 2 mmol), tin tetrachloride (521 mg, 0.23 mL, 2 mmol) and trimethylsilyl cyanide (3.97 g, 5 mL, 40 mmol) obtained in step (S4) as reaction raw materials (the molar ratio of the fluorinated acceptor unit based on oxygen-boron-nitrogen coordination, tin tetrachloride and trimethylsilyl cyanide is 1:1:20), placed in 20 mL of ultra-dry dichloromethane for substitution reaction (reaction temperature is room temperature, reaction time is 12 h), after the reaction is completed, the crude product is recrystallized using dichloromethane and n-hexane to obtain 496 mg of the cyanated acceptor unit based on oxygen-boron-nitrogen coordination (H NMR spectrum is as follows: Figure 7 As shown), the yield is 50%;

[0110] The chemical structure of the cyanation acceptor unit based on oxygen-boron-nitrogen coordination is shown below:

[0111]

[0112] Example 3

[0113] This embodiment provides a method for preparing an n-type polymer P1, comprising the following steps:

[0114] (A1) The fluorinated receptor unit based on oxygen-boron-nitrogen coordination prepared in Example 1 (2.00 g, 3.08 mmol) and N-bromosuccinimide (1.21 g, 6.79 mmol) were used as reaction raw materials (the molar ratio of 3,8-bis(2-ethylhexyl)-tetrafluoro-5,10-di(thiophen-2-yl)-benzobis([1,3,2]oxazoline) to N-bromosuccinimide was 1:2.2), placed in 20 mL of chloroform for bromination reaction (reaction temperature was 50° C., reaction time was 6 h), and after the reaction was completed, the crude product was further purified by silica gel column using ethyl acetate and petroleum ether as eluents (the volume ratio of ethyl acetate to petroleum ether was 1:4) to obtain 1.38 g of fluorinated receptor unit based on oxygen-boron-nitrogen coordination substituted by bromine (H NMR spectrum was as follows: Figure 8 As shown), the yield is 80%;

[0115] The chemical structure of the fluorinated acceptor unit based on oxygen-boron-nitrogen coordination substituted by bromine is shown below:

[0116]

[0117] (A2) The bromine-substituted oxygen-boron-nitrogen coordinated fluorinated acceptor unit (80.6 mg, 0.1 mmol), 2,5-bis(2-octyldodecyl)-3,6-bis(5-(trimethyltinyl)thiophene-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (118.7 mg, 0.1 mmol), tridibenzylideneacetone dipalladium (4.58 mg, 0.05 mmol), and tri(o-methylphenyl)phosphine (3.04 mg, 0.1 mmol) prepared in step (A1) were used as reaction raw materials (bromine-substituted oxygen-boron-nitrogen coordinated fluorinated acceptor unit, 2,5-bis(2-octyldodecyl)-3,6-bis(5-(trimethyltinyl)thiophene-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione) The molar ratio of trimethyltin-1-thiophene-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione, tridibenzylideneacetone dipalladium and tri(o-methylphenyl)phosphine was 1:1:0.05:0.1, dissolved in 3.3 mL toluene, replaced with nitrogen three times, heated under reflux, and Stille polymerization was carried out (reaction temperature was 110°C, reaction time was 12 h). After the polymerization, a capping agent was added for capping. After the reaction, the reaction solution was dripped into methanol, and the solid was collected by filtration. The solid was purified by Soxhlet extractor, and methanol, acetone, n-hexane and chloroform were used as extractants respectively. Finally, the chloroform extract was concentrated and dripped into methanol to obtain a black solid, which was 82 mg of n-type polymer P1 (yield 55%). Its absorption spectrum is shown as follows: Fig. 9 As shown;

[0118] Wherein, the chemical structure of the n-type polymer P1 is shown as follows:

[0119] n is an integer greater than 0.

[0120] The prepared n-type polymer P1 was subjected to high temperature gel chromatography analysis (1,2,4-trichlorobenzene solvent, polystyrene standard sample): M n : 56.0kDa, PDI: 2.8.

[0121] Example 4

[0122] This embodiment provides a method for preparing an n-type polymer P2, comprising the following steps:

[0123] (A1) The oxygen-boron-nitrogen coordinated cyanation acceptor unit (1 g, 1.24 mmol), tin tetrachloride (323 mg, 0.15 mL, 1.24 mmol) and trimethylsilyl cyanide (2.46 g, 3.10 mL, 24.81 mmol) obtained in Example 2 were used as reaction raw materials (the molar ratio of the oxygen-boron-nitrogen coordinated fluorinated acceptor unit, tin tetrachloride and trimethylsilyl cyanide was 1:1:20), and the mixture was placed in 20 mL of ultra-dry dichloromethane for substitution reaction (the reaction temperature was room temperature and the reaction time was 12 h). After the reaction, the crude product was recrystallized from dichloromethane and n-hexane to obtain 500 mg of the oxygen-boron-nitrogen coordinated cyanation acceptor unit (H NMR spectrum was as follows: Fig.10 As shown), the yield is 50%;

[0124] The chemical structure of the cyanation acceptor unit based on oxygen-boron-nitrogen coordination substituted by bromine is shown below:

[0125]

[0126] (A2) The bromine-substituted oxygen-boron-nitrogen-coordinated cyanation acceptor unit (83.4 mg, 0.1 mmol), 2,5-bis(2-octyldodecyl)-3,6-bis(5-(trimethyltinyl)thiophene-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (118.7 mg, 0.1 mmol), tridibenzylideneacetone dipalladium (4.58 mg, 0.05 mmol), and tri(o-methylphenyl)phosphine (3.04 mg, 0.1 mmol) prepared in step (A1) were used as raw materials (bromine-substituted oxygen-boron-nitrogen-coordinated cyanation acceptor unit, 2,5-bis(2-octyldodecyl)-3,6-bis(5-(trimethyltinyl)thiophene-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione) (trimethyltinyl)thiophene-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione, tridibenzylideneacetone dipalladium, tri(o-methylphenyl)phosphine (molar ratio of 1:1:0.05:0.1) were dissolved in 2 mL of toluene, nitrogen was replaced three times, and the mixture was heated under reflux to perform Stille polymerization (reaction temperature was 110°C, reaction time was 48 h). After the polymerization, a capping agent was added for capping. After the reaction, the reaction solution was dripped into methanol and the solid was collected by filtration. The solid was purified by Soxhlet extractor, and methanol, acetone, n-hexane and chloroform were used as extractants respectively. Finally, the chloroform extract was concentrated and dripped into methanol to obtain a black solid, which was 78 mg of n-type polymer P2 (yield 52%). Its absorption spectrum is shown in Fig.11 shown.

[0127] Wherein, the chemical structure of the n-type polymer P2 is shown as follows:

[0128] n is an integer greater than 0.

[0129] The prepared polymer P2 was subjected to high temperature gel chromatography analysis (1,2,4-trichlorobenzene solvent, polystyrene standard sample): M n : 11.0kDa, PDI: 2.6.

[0130] Example 5

[0131] This embodiment provides an organic field effect transistor. The structure of the organic field effect transistor is top gate and bottom contact, and the specific preparation process is as follows:

[0132] A 200μm thick Si / SiO2 sheet was used as a substrate, and after ultrasonic cleaning in water, ethanol, and acetone, it was vacuum dried at 80°C; the source and drain electrodes were placed on the upper surface of the substrate, wherein the source and drain electrodes were 25nm thick gold electrodes thermally evaporated by a mask, and the device channel width was 4500μm and the channel length was 50μm. Polymer P1 was dissolved in o-dichlorobenzene to a concentration of 8mg / mL to obtain a polymer solution; the polymer solution was formed on the Si / SiO2 sheet substrate by a homogenization method and annealed on a 160°C hot stage for 10 minutes. Subsequently, a 60mg / mL PMMA n-butyl acetate solution was spin-coated on the surface of the polymer film to form a 500nm thick insulating layer, and the solvent was removed at 90°C for 60 minutes. Finally, a 50nm thick gold was thermally evaporated on the insulating layer by a mask as a gate electrode to complete the preparation of the organic field effect transistor.

[0133] The device performance of the prepared field effect transistor was tested by Keithley 4200SCS semiconductor tester in a nitrogen-filled glove box.

[0134] The organic field effect transistor device prepared as above in this embodiment was tested, and the results are shown in Table 1:

[0135] Table 1 Performance test results of the organic field effect transistor of this embodiment

[0136] polymer <![CDATA[Electron mobility (cm 2 V -1 s -1 )]]> Threshold voltage (V) On / Off Ratio P1 3.04 0～10 <![CDATA[10 5 ~10 6 ]]>

[0137] Example 6

[0138] This embodiment provides an organic field effect transistor. The structure of the organic field effect transistor is top gate and bottom contact, and the specific preparation process is as follows:

[0139] A 200μm thick Si / SiO2 sheet was used as a substrate, and after ultrasonic cleaning in water, ethanol, and acetone, it was vacuum dried at 80°C; the source and drain electrodes were placed on the upper surface of the substrate, wherein the source and drain electrodes were 25nm thick gold electrodes thermally evaporated by a mask plate, and the device channel width was 4500μm and the channel length was 50μm. Polymer P2 was dissolved in o-dichlorobenzene to a concentration of 8mg / mL to obtain a polymer solution; the polymer solution was formed on the Si / SiO2 sheet substrate by a homogenization method and annealed on a 160°C hot stage for 10 minutes. Subsequently, a 60mg / mL PMMA n-butyl acetate solution was spin-coated on the surface of the polymer film to form a 500nm thick insulating layer, and the solvent was removed at 90°C for 60 minutes. Finally, a 50nm thick gold was thermally evaporated on the insulating layer by a mask plate as a gate electrode to complete the preparation of the organic field effect transistor.

[0140] The device performance of the prepared field effect transistor was tested by Keithley 4200SCS semiconductor tester in a nitrogen-filled glove box.

[0141] The organic field effect transistor device prepared as above in this embodiment was tested, and the results are shown in Table 2:

[0142] Table 2 Performance test results of the organic field effect transistor of this embodiment

[0143]

[0144]

[0145] Example 7

[0146] This embodiment provides a method for preparing a semiconductor thin film, which specifically includes the following steps:

[0147] A Si / SiO2 sheet with a thickness of 200 μm is used as a substrate, which is ultrasonically cleaned in water, ethanol and acetone twice and then vacuum dried at 80°C; source and drain electrodes are placed on the upper surface of the substrate, wherein the source and drain electrodes are 25 nm thick gold electrodes evaporated from a mask plate, the device channel width is 4500 μm, and the channel length is 50 μm; polymer P1 is dissolved in o-dichlorobenzene to a concentration of 8 mg / mL to obtain a polymer solution; 4-(1,3-dimethyl-2,3-dihydro-1H-benzimidazol-2-yl)-N,N-dimethylaniline is selected as a dopant and dissolved in n-butyl acetate to a concentration of 1.2 mg / mL to obtain a dopant solution; the polymer solution and the dopant solution are mixed and then an active layer is formed on the Si / SiO2 substrate by a homogenization method, and annealed on a hot plate at 160°C for 10 minutes. After the annealing is completed, a semiconductor film is obtained.

[0148] The prepared semiconductor film is transferred to the probe station for testing of conductivity and Seebeck coefficient. Power factor = conductivity × Seebeck coefficient 2 The results are shown in Table 3:

[0149] Table 3 Organic hot spot performance test results of this embodiment

[0150] polymer <![CDATA[Conductivity (S cm -1 )]]> <![CDATA[Seebeck coefficient (μV K -1 )]]> <![CDATA[Power factor (μW m -1 K -2 )]]> P1 9.8 -285.2 63.9

[0151] Example 8

[0152] This embodiment provides a method for preparing a semiconductor thin film, which specifically includes the following steps:

[0153] A Si / SiO2 sheet with a thickness of 200 μm is used as a substrate, which is ultrasonically cleaned in water, ethanol and acetone twice and then vacuum dried at 80°C; source and drain electrodes are placed on the upper surface of the substrate, wherein the source and drain electrodes are 25 nm thick gold electrodes evaporated from a mask plate, the device channel width is 4500 μm, and the channel length is 50 μm; polymer P2 is dissolved in o-dichlorobenzene to a concentration of 8 mg / mL to obtain a polymer solution; 4-(1,3-dimethyl-2,3-dihydro-1H-benzimidazol-2-yl)-N,N-dimethylaniline is selected as a dopant and dissolved in n-butyl acetate to a concentration of 1.2 mg / mL to obtain a dopant solution; the polymer solution and the dopant solution are mixed and then an active layer is formed on the Si / SiO2 substrate by a homogenization method, and annealed on a hot stage at 160°C for 10 minutes. After the annealing is completed, a semiconductor film is obtained.

[0154] The prepared semiconductor film is transferred to the probe station for testing of conductivity and Seebeck coefficient. Power factor = conductivity × Seebeck coefficient 2 The results are shown in Table 4:

[0155] Table 4 Organic thermoelectric performance test results of this embodiment

[0156] polymer <![CDATA[Conductivity (S cm -1 )]]> <![CDATA[Seebeck coefficient (μV K -1 )]]> <![CDATA[Power factor (μW m -1 K -2 )]]> P2 95.5 -148.6 147.8

[0157] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the explanation of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. An acceptor unit based on oxygen-boron-nitrogen coordination, characterized in that: The chemical structural formula of the receptor unit is shown in the following formula (I): In formula (I), m1 and m2 are independently 0 or 1; x1, x2, y1 and y2 are independently any integer from 1 to 20; R is a fluorine atom or a cyano group; Ar is one of the following structures: Wherein, X1, X2, X3 and X4 are independently selected from one of methyl, ethyl, isopropyl, methoxy, fluorine or chlorine, and Y1 and Y2 are independently selected from one of nitrogen or hydrogen.

2. A method for preparing an oxygen-boron-nitrogen coordinated receptor unit, characterized in that: The following steps are involved: (S1) placing 2,5-dihydroxy-1,4-benzenedicarbaldehyde and an alkylamine in a first solvent to react to obtain a Schiff base intermediate; (S2) placing the Schiff base intermediate prepared in step (S1), N,N-diisopropylethylamine and boron trifluoride ether complex in a second solvent to react to obtain 3,8-bis(alkyl)-tetrafluoro-benzobis([1,3,2]oxazoline); (S3) placing the 3,8-bis(alkyl)-tetrafluoro-benzobis([1,3,2]oxazoline) prepared in step (S2) and liquid bromine in a third solvent, and reacting with a first catalyst to obtain 3,8-bis(alkyl)-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline); (S4) placing the 3,8-bis(alkyl)-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline) and aryltin prepared in step (S3) in a fourth solvent, and reacting with a second catalyst to obtain a first receptor unit; Or, (S5) placing the first receptor unit prepared in step (S4), tin tetrachloride and trimethylsilyl cyanide in a fifth solvent to obtain a second receptor unit after reaction; The receptor unit based on oxygen-boron-nitrogen coordination is the first receptor unit or the second receptor unit; Wherein, the chemical structural formula of the first receptor unit is shown in formula (II), and the chemical structural formula of the second receptor unit is shown in formula (III); Wherein, in formula (II) and formula (III), m1 and m2 are independently 0 or 1; x1, x2, y1 and y2 are independently any integer from 1 to 20; Ar is one of the following structures: Wherein, X1, X2, X3 and X4 are independently selected from one of methyl, ethyl, isopropyl, methoxy, fluorine or chlorine, and Y1 and Y2 are independently selected from one of nitrogen or hydrogen.

3. The method for preparing an oxygen-boron-nitrogen coordinated receptor unit according to claim 2, characterized in that: In step (S1), the molar ratio of 2,5-dihydroxy-1,4-benzenedicarbaldehyde to alkylamine is 1:2.1-3; During the reaction, the temperature is 60-100°C and the time is 2.5-12h; In step (S2), the molar ratio of the Schiff base intermediate, ultra-dry N,N-diisopropylethylamine and ultra-dry boron trifluoride etherate is 1:5-10:5-10; During the reaction, the temperature is 25-80°C and the reaction time is 6-24h; In step (S3), the molar ratio of 3,8-bis(alkyl)-tetrafluoro-benzobis([1,3,2]oxazoline) to liquid bromine is 1:10-20; During the reaction, the temperature is 25-60°C and the reaction time is 4-12 hours; In step (S4), the molar ratio of 3,8-bis(alkyl)-tetrafluoro-5,10-dibromo-benzobis([1,3,2]oxazoline) to aryltin is 1:2-4; During the reaction, the temperature is 90-120°C and the reaction time is 12-24h; In step (S5), the molar ratio of the first receptor unit, tin tetrachloride and trimethylsilyl cyanide is 1:10-20:10-20; During the reaction, the temperature is room temperature and the time is 12 to 24 hours.

4. Application of an oxygen-boron-nitrogen coordination-based acceptor unit in the preparation of n-type polymers.

5. An n-type polymer, characterized in that Prepared from the oxygen-boron-nitrogen coordination-based acceptor unit according to claim 1, the chemical structure of the n-type polymer is shown in formula (V): Wherein, in formula (V), m1, m2, m3 and m4 are independently 0 or 1; n is an integer greater than 0; x1, x2, x3, x4, y1, y2, y3 and y4 are independently any integer from 1 to 20; R is a fluorine atom or a cyano group; Ar is one of the following structures: Wherein, X1, X2, X3 and X4 are independently selected from one of methyl, ethyl, isopropyl, methoxy, fluorine or chlorine, and Y1 and Y2 are independently selected from one of nitrogen or hydrogen.

6. A method for preparing an n-type polymer, characterized in that: The following steps are involved: (A1) placing an oxygen-boron-nitrogen coordination-based acceptor unit and N-bromosuccinimide in a sixth solvent to react to obtain a bromine-substituted oxygen-boron-nitrogen coordination-based acceptor unit; (A2) dissolving the bromine-substituted oxygen-boron-nitrogen coordinated receptor unit prepared in step (A1), alkyl-substituted thienyl pyrrolopyrrole diketotin, tridibenzylideneacetone dipalladium and tri(o-methylphenyl)phosphine in a seventh solvent, and performing post-treatment after the reaction to obtain the n-type polymer as claimed in claim 5.

7. The method for preparing an n-type polymer according to claim 6, characterized in that: In step (A1), the molar ratio of the oxygen-boron-nitrogen coordinated acceptor unit to N-bromosuccinimide is 1:2 to 1:3; During the reaction, the temperature is 25-50°C and the reaction time is 2-8h; In step (A2), the molar ratio of the bromine-substituted oxygen-boron-nitrogen-coordinated acceptor unit, the alkyl-substituted thienylpyrrolopyrrole diketotin, trisdibenzylideneacetone dipalladium, and tri(o-methylphenyl)phosphine is 1:1:0.05-0.1:0.05-0.1; During the reaction, the temperature is 90-110°C and the time is 12-48 hours.

8. Use of the n-type polymer according to claim 5 in preparing an organic field effect transistor or an organic thermoelectric material.

9. An organic field effect transistor, characterized in that: The organic field effect transistor is prepared from the n-type polymer described in claim 5.

10. An organic thermoelectric material, characterized in that: The organic thermoelectric material is prepared from the n-type polymer described in claim 5.

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