Receptor unit with skeleton containing cyclic thiophene, thiophene 2-position bromination substitution and side chain alkyl substitution, and preparation and application thereof

Abstract

The invention relates to the technical field of organic chemical molecular design and organic photoelectric materials, in particular to an acceptor unit with a skeleton containing cyclic thiophene, thiophene 2-position bromination substitution and side chain alkyl substitution, and preparation and application thereof. According to the present invention, the receptor unit with the skeleton containing the cyclic thiophene, the thiophene 2-position bromination substitution and the side chain alkyl substitution is the naphthalene diimide derivative receptor unit based on the single thiophene expansion, and further, the n-type polymer organic molecule prepared based on the receptor unit shows the strong electron withdrawing ability; the enhancement effect is attributed to a deeper LUMO energy level and a more planar skeleton of an acceptor unit, which is crucial to efficient charge transfer in OFETs. According to the invention, it is found that n-type charge transfer is effectively enhanced by introducing a thiophene spacer into NTI-BTT.

Description

Technical Field

[0001] The present invention relates to the technical fields of organic chemical molecular design and organic optoelectronic materials, and particularly relates to an acceptor unit with a cyclic thiophene-containing backbone, bromination substitution at the 2-position of thiophene, and alkyl substitution on the side chain, and its preparation and application. Background Art

[0002] With the development of scientific and technological innovation and economic development, existing rigid, hard and brittle semiconductor electronic materials can no longer meet people's application requirements for high performance, portability and flexible scenarios. Compared with inorganic materials, organic materials have mechanical flexibility, cost-effectiveness and light-weight characteristics, and organic optoelectronic devices are crucial for the development of advanced electronic devices in the Internet of Things (IoT). In addition, new organic electronic devices based on organic semiconductor materials, such as flexible wearable electronic devices, organic field-effect transistors, photovoltaics, thermoelectrics, biosensors, and optoelectronic storage, have shown strong application potential in the fields of energy storage-conversion, electronic information, biosensing, medical health, military, aerospace, etc. In the design of organic semiconductor materials, according to the different carrier transport types, organic semiconductors can be divided into n-type, p-type and bipolar. Compared with unipolar circuits, p-n complementary logic circuits have lower power consumption, more compact physical layouts, higher signal-to-noise ratios, and excellent anti-interference capabilities. Currently, the carrier mobilities of p-type and bipolar semiconductor materials are often greater than 10 cm 2 V -1 s -1 , however, the carrier mobility of n-type semiconductor materials is often lower than 5 cm 2 V -1 s -1 . The mismatched mobility and air stability problems greatly limit the development of organic p-n complementary logic circuits. Therefore, designing n-type organic semiconductor materials with high mobility and good air stability is an urgent problem to be solved in the large-scale application of organic electronic devices.

[0003] In the development route of n-type organic semiconductor materials with high mobility, designing a molecular structure of a strong electron-deficient acceptor unit with the lowest unoccupied molecular orbital (LUMO) energy level lower than -4.0 eV is the key to achieving efficient electron injection and obtaining good air stability. Naphthalene diimide (NDI) has attracted extensive attention due to its strong π-π interaction, electron-withdrawing ability, and good chemical and thermal stability. Although most π-extended NDI derivatives have two fused (hetero)aromatic rings in the naphthalene part, relatively few single (hetero)aromatic ring-fused NDI derivatives are recorded in the literature. In addition, the electron mobilities of most reported single (hetero)aromatic ring-fused NDI derivatives are relatively low, usually between 10 -2 and 10 -3 cm 2 V -1 s-1 It is difficult to meet the requirements of practical applications.

[0004] In summary, it is crucial to design and synthesize novel single (hetero) aromatic ring-fused NDI derivatives, which will contribute to the development of n-type organic semiconductor materials with higher electron mobility and excellent air stability, providing certain design ideas and theoretical guidance for promoting the industrialization of high-performance organic electronic devices. Summary of the Invention

[0005] To solve the above problems, the object of the present invention is to provide a receptor unit with a cyclic thiophene-containing backbone, bromination substitution at the 2-position of thiophene, and alkyl substitution on the side chain, as well as its preparation and application. By developing conjugated molecules with low LUMO energy levels, the problem of low electron mobility of current n-type organic semiconductor materials is solved, and the prepared polymeric organic molecules are used as n-type organic semiconductor materials in related electronic devices.

[0006] The object of the present invention can be achieved by the following technical solutions:

[0007] The first object of the present invention is to provide a receptor unit with a cyclic thiophene-containing backbone, bromination substitution at the 2-position of thiophene, and alkyl substitution on the side chain. The chemical structural formula of the receptor unit is shown in formula (I):

[0008]

[0009] Wherein, m and n independently selected from integers of 0 to 4, and x and y independently selected from integers of 1 to 20.

[0010] In an embodiment of the present invention, the chemical structural formula of the receptor unit is shown in the following formula:

[0011]

[0012] The second object of the present invention is to provide a preparation method of a receptor unit with a cyclic thiophene-containing backbone, bromination substitution at the 2-position of thiophene, and alkyl substitution on the side chain, comprising the following steps:

[0013] (S1) Mix 1,4,5,8-naphthalenetetracarboxylic dianhydride (NDA), 1,3-dibromo-5,5-dimethylthiazoline (DBH) with concentrated sulfuric acid and carry out bromination reaction, and then perform post-treatment to obtain a crude product: NDA-Br;

[0014] (S2) Mix the NDA-Br prepared in step (S1), 2-n-octyl-1-dodecylamine with acetic acid and carry out a branching reaction, and then perform post-treatment to obtain a first compound;

[0015] (S3) Mix the first compound prepared in step (S2), a palladium catalyst, tris(ortho-methylphenyl)phosphine, a copper catalyst, triethylamine, and trimethylsilylacetylene, and then carry out a Sonogashira coupling reaction, followed by post-treatment to obtain a second compound;

[0016] (S4) Mix the second compound prepared in step (S3), sodium sulfide, and ethanol, and then carry out a cyclization reaction to form thiophene, followed by post-treatment to obtain a third compound;

[0017] (S5) Mix the third compound prepared in step (S4), dichloromethane, and bromine, and then carry out a bromination reaction to obtain a receptor unit with a cyclic thiophene in the backbone, a bromine substitution at the 2-position of the thiophene, and an alkyl substitution in the side chain;

[0018] Among them, the chemical structural formula of NDA-Br is shown in formula (II), the chemical structural formula of the first compound is shown in formula (III), the chemical structural formula of the second compound is shown in formula (IV), and the chemical structural formula of the third compound is shown in formula (V):

[0019]

[0020] Among them, in formula (III), formula (IV), and formula (V), m is an integer selected from 0 to 4, n is an integer selected from 0 to 4, x is an integer selected from 1 to 20, and y is an integer selected from 1 to 20.

[0021] In the present invention, the preparation process of the receptor unit with strong electron-withdrawing properties is shown in the following formula:

[0022]

[0023] In one embodiment of the present invention, in step (S1), the dosage ratio of 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,3-dibromo-5,5-dimethylhydantoin, and concentrated sulfuric acid is 1 mmol: 0.5 - 2.5 mmol: 60 - 240 mL;

[0024] During the bromination reaction, the temperature is 60 - 120 °C, and the time is 2 - 24 h;

[0025] In step (S2), the dosage ratio of NDA-Br, 2-n-octyl-1-dodecylamine, and acetic acid is 1 - 7 mmol: 1 mmol: 2.5 - 30 mL;

[0026] During the branching reaction, the temperature is 30 - 150 °C, and the time is 2 - 12 h.

[0027] In one embodiment of the present invention, in step (S3), the palladium catalyst is selected from one or more of dichloro (triphenylphosphine) platinum, tris (dibenzylideneacetone) dipalladium, palladium acetate, tetrakis (triphenylphosphine) palladium, bis (acetylacetone) palladium, dichloro (ethylenediamine) palladium, or bis (triphenylphosphine) diacetate palladium;

[0028] The copper catalyst is selected from one or more of copper sulfide, cuprous sulfide, or cuprous iodide;

[0029] The dosage ratio of the first compound, palladium catalyst, tris (o - methylphenyl) phosphine, copper catalyst, anhydrous triethylamine, and trimethylsilylacetylene is 5.525 mmol: 0.1 - 0.3 mmol: 0.1 - 0.5 mmol: 0.1 - 0.5 mmol: 10 - 15 mL: 2 - 20 mmol;

[0030] The Sonogashira coupling reaction is carried out under a nitrogen atmosphere, at a temperature of 60 - 150 °C for 2 - 12 h.

[0031] In one embodiment of the present invention, in step (S4), the dosage ratio of the second compound, sodium sulfide, and ethanol is 4.53 mmol: 10 - 15 mmol: 20 - 60 mL;

[0032] The cyclization of thiophene reaction is carried out under a nitrogen atmosphere, at a temperature of 60 - 120 °C for 6 - 24 h;

[0033] In step (S5), the dosage ratio of the third compound, dichloromethane, and bromine is 2.72 mmol: 10 mL: 20 - 30 mmol;

[0034] The bromination reaction is carried out under a nitrogen atmosphere, at a temperature of 30 - 90 °C for 2 - 15 h.

[0035] In one embodiment of the present invention, in step (S1), the post - treatment is to filter and collect the precipitate, and then wash and dry it successively;

[0036] In step (S2), the post - treatment is to extract, purify, and dry it successively;

[0037] In step (S3), the post - treatment is to extract, purify, and dry it successively;

[0038] In step (S4), the post - treatment is to extract, purify, and dry it successively;

[0039] In step (S5), the post - treatment is to extract, purify, and dry it successively;

[0040] Among them, in steps (S2) to (S5), the eluent used in the extraction process is a mixture of dichloromethane and petroleum ether, wherein the volume ratio of dichloromethane to petroleum ether is 1 to 2: 2 to 10.

[0041] The third object of the present invention is to provide an application of a receptor unit having a cyclic thiophene-containing skeleton, brominated substitution at the 2-position of thiophene, and alkyl substitution on the side chain in the preparation of n-type polymeric organic molecules.

[0042] The fourth object of the present invention is to provide a method for preparing an n-type polymeric organic molecule, comprising the following steps:

[0043] Mix the first raw material, a receptor unit having a cyclic thiophene-containing skeleton, brominated substitution at the 2-position of thiophene, and alkyl substitution on the side chain, a palladium catalyst, an initiator, and a solvent, and then carry out a coupling reaction, and perform post-treatment to obtain an n-type polymeric organic molecule;

[0044] The first raw material is selected from one of 2,1,3-benzothiadiazole-4,7-bis(pinacol borate) (BT) or 4,7-bis(5-(trimethylstannyl)thiophen-2-yl)benzo[c][1,2,5]thiadiazole (BTT).

[0045] In one embodiment of the present invention, the initiator is selected from one of tri-n-octylmethylammonium chloride or P(o-tol) 3 among them;

[0046] The solvent is toluene;

[0047] The molar ratio of the first raw material, the receptor unit having a cyclic thiophene-containing skeleton, brominated substitution at the 2-position of thiophene, and alkyl substitution on the side chain, and the palladium catalyst is 0.2 to 1: 0.2 to 1: 0.01 to 0.2;

[0048] During the coupling reaction, the temperature is 30 to 150 °C, and the time is 6 to 24 h.

[0049] In the present invention, the preparation process of the n-type polymeric organic molecule is shown by the following formula:

[0050]

[0051] Among them, m is an integer selected from 0 to 4, n is an integer selected from 0 to 4, x is an integer selected from 1 to 20, and y is an integer selected from 1 to 20.

[0052] The fifth object of the present invention is to provide an n-type polymeric organic molecule, and the n-type polymeric organic molecule is prepared by the above method.

[0053] The sixth object of the present invention is to provide an application of an n-type polymeric organic molecule in the preparation of an organic optoelectronic device, wherein the n-type polymeric organic molecule serves as a semiconductor transport layer (which can be prepared by spin coating, drop coating, blade coating, dip coating, inkjet printing or spray coating methods).

[0054] In one embodiment of the present invention, the organic optoelectronic device is selected from one of a field effect transistor, an electrochemical transistor, an electroluminescent transistor, a solar cell, a photoconductive device, an optical switch, a sensor, a modulator or a photodetector;

[0055] wherein the structure of the field effect transistor is selected from one of a bottom gate bottom contact type, a top gate top contact type, a top gate bottom contact type or a bottom gate top contact type.

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

[0057] The acceptor unit provided by the present invention with a skeleton containing cyclic thiophene, bromination substitution at the 2-position of thiophene, and side chain alkyl substitution is a naphthalene diimide derivative acceptor unit based on single thiophene expansion. Further, the n-type polymeric organic molecule prepared based on this acceptor unit exhibits stronger electron-withdrawing ability; this enhancement is attributed to the deeper LUMO energy level and more planar skeleton of the acceptor unit, which is crucial for efficient charge transport in OFETs.

[0058] The present invention discovers that introducing a thiophene spacer in NTI-BTT effectively enhances n-type charge transport. The novel molecular modification strategy improves π-π interaction and reduces the intermolecular distance, resulting in the π-π stacking distance being shortened to Therefore, NTI-BTT exhibits a significantly improved electron mobility, which is four times higher than that of the traditional reported NDI-based counterparts. The molecular modification strategy provided by the present invention demonstrates the structure-activity relationship between intermolecular interaction and charge transport characteristics, and can achieve a significant improvement in electron mobility, paving the way for the development of more efficient and powerful organic optoelectronic devices. Description of the Drawings

[0059] Figure 1 1H NMR spectrum of the first compound prepared in Example 1;

[0060] Figure 2 1H NMR spectrum of the second compound prepared in Example 1;

[0061] Figure 3 1H NMR spectrum of the third compound prepared in Example 1;

[0062] Figure 4 1H NMR spectrum of the target product prepared in Example 1;

[0063] Figure 5 1H NMR spectrum of the trimer compound NDI-BTT prepared as Comparative Example 1;

[0064] Figure 6 1H NMR spectrum of the trimer compound NTI-BT prepared as Example 2;

[0065] Figure 7 1H NMR spectrum of the trimer compound NTI-BTT prepared as Comparative Example 2;

[0066] Figure 8 Performance test chart of the organic field effect transistor device prepared using the trimer compounds NDI-BTT, NTI-BT, and NTI-BTT; where (a, d) is NDI-BTT; (b, e) is NTI-BT; (c, f) is NTI-BTT. Detailed implementation mode

[0067] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0068] In the following examples, unless otherwise specified, the reagents used are commercially available reagents, and the monitoring means and methods used are conventional detection means and methods in the art.

[0069] Example 1

[0070] This example provides a preparation method for a receptor unit having a skeleton containing a cyclic thiophene, bromination substitution at the 2-position of the thiophene, and an alkyl substitution in the side chain. The synthetic route is shown in the following formula:

[0071]

[0072] (S1) Add 1,4,5,8-naphthalenetetracarboxylic dianhydride (NDA, 5.364 g, 20 mmol) to a 500 mL single-necked round-bottom flask without nitrogen protection; then, add concentrated sulfuric acid (120 mL) and stir evenly; then, add 1,3-dibromo-5,5-dimethylthiazoline (DBH, 3.431 g, 12 mmol); seal the opening of the flask with waterproof tape to prevent bromine gas from escaping during the reaction. Then, place the resulting mixture in a reaction at 60 °C for 24 hours. After the reaction is completed, cool to room temperature, pour the reaction mixture into a beaker containing ice chips; then, collect the yellow precipitate by filtration, wash it three times with methanol, and finally dry it under vacuum at 60 °C for 12 hours. Obtain the crude product: NDA-Br (yield is about 94%).

[0073] (S2) Add NDA-Br (6.53 g, 18.82 mmol) prepared in step (S1) into a 500 mL two-necked round-bottom flask, and add a magnetic stir bar under a nitrogen atmosphere; then, add acetic acid (180 mL) and stir for 5 minutes, and then add 2-n-octyl-1-dodecylamine (16.8 g, 56.46 mmol); place the resulting mixture at 90 °C and react for 12 hours (with continuous stirring). After the reaction is completed, cool to room temperature and evaporate acetic acid; then, add saturated NaHCO 3 solution dropwise, continue stirring until acetic acid completely reacts (bubbles should stop after adding saturated NaHCO 3 solution); then, extract with dichloromethane through a separatory funnel, dry with anhydrous sodium sulfate to remove water; after concentration, remove the solvent using a rotary evaporator, and purify by silica gel column chromatography (200 - 400 mesh), with the mobile phase being a mixture of petroleum ether and dichloromethane (the volume ratio of petroleum ether to dichloromethane is 3:1), to obtain an orange-red oily solid: the first compound (yield is about 34%, and the 1H NMR spectrum is as shown in Figure 1 ). 1H NMR (400 MHz, CDCl3): δ8.94 (s, 1H), 8.82 (d, J = 7.6 Hz, 1H), 8.77 (d, J = 7.7 Hz, 1H), 4.14 (dd, J = 15.9, 7.2 Hz, 4H), 2.04 - 1.94 (m, 2H), 1.56 (s, 2H), 1.47 - 1.14 (m, 73H), 0.86 (q, J = 6.5 Hz, 13H)

[0074] 13C NMR (100 MHz, CDCl3): δ163.08, 162.53, 162.36, 161.61, 138.79, 132.00, 131.04, 128.95, 126.99, 126.21, 126.14, 124.15, 45.55, 45.30, 36.81, 36.69, 32.15, 32.11, 31.82, 31.77, 30.28, 30.21, 29.86, 29.83, 29.78, 29.58, 29.53, 26.63, 26.57, 22.92, 22.90, 14.36

[0075] MALDI-TOF MS (Mw = 904.5693): found m / z = 905.3840 ([M]+)

[0076] (S3) Add the first compound (5 g, 5.525 mmol) prepared in step (S2), bis(triphenylphosphine)platinum dichloride (195.86 mg, 0.276 mmol), and copper(I) iodide (52.5 mg, 0.276 mmol) into a 250 mL two-necked round-bottom flask. Then add anhydrous triethylamine (50 mL). After stirring for 5 minutes, add trimethylsilylacetylene (663 mg, 6.63 mmol). Heat the resulting mixture to 90 °C and react for 12 hours. After the reaction is completed, cool it to room temperature, pour the reaction solution into 200 mL of brine, and extract with dichloromethane. Collect the organic phase and dry it with anhydrous sodium sulfate. After concentration, purify it by silica gel column chromatography (200 - 300 mesh), and the mobile phase is a mixture of petroleum ether and dichloromethane (the volume ratio of petroleum ether to dichloromethane is 3:1) to obtain a yellow oily product: the second compound (yield is about 82%, and the 1H NMR spectrum is as shown in Figure 2 shown).

[0077] 1H NMR (400 MHz, CDCl3): δ 8.77 (d, J = 5.8 Hz, 2H), 8.71 (d, J = 7.7 Hz, 1H), 4.12 (t, J = 7.3 Hz, 4H), 1.95 (s, 2H), 1.21 (s, 77H), 0.85 (q, J = 6.4 Hz, 14H), 0.37 (s, 9H)

[0078] 13C NMR (100 MHz, CDCl3): δ 162.99, 137.73, 131.64, 131.11, 127.38, 126.70, 126.57, 125.96, 125.51, 45.18, 45.02, 36.82, 36.62, 32.14, 31.78, 30.26, 30.21, 29.88, 29.83, 29.56, 29.51, 26.65, 26.53, 22.89, 14.34

[0079] MALDI-TOF MS (Mw = 922.6983): found m / z = 923.5562 ([M]+)

[0080] (S4) The second compound (4.18 g, 4.53 mmol) prepared in step (S3) and sodium sulfide nonahydrate (3.26 g, 13.59 mmol) were added to a 250 mL two-necked round-bottom flask. Ethanol (60 mL) was added under a nitrogen atmosphere, and the mixture was heated to 60 °C and reacted for 12 hours. After the reaction, it was cooled to room temperature and exposed to air, and stirred for 3 hours; after the reaction was terminated, water was added, and the product was extracted with dichloromethane; the organic phase was collected and dried over anhydrous sodium sulfate; after concentration, the solvent was removed using a rotary evaporator, and purification was carried out by silica gel column chromatography (200 - 400 mesh), with the mobile phase being a mixture of petroleum ether and dichloromethane (the volume ratio of petroleum ether to dichloromethane was 2:1); a yellow oily product was obtained: the third compound (yield was about 60%, and the 1H NMR spectrum was as shown in Figure 3 shown).

[0081] 1H NMR (400 MHz, CDCl3): δ 9.02 (s, 1H), 8.76 (s, 2H), 4.19 (t, J = 6.2 Hz, 4H), 2.05 (d, J = 6.5 Hz, 2H), 1.58 (s, 1H), 1.42 - 1.15 (m, 82H), 0.84 (q, J = 7.3 Hz, 16H), 0.52 (s, 9H)

[0082] 13C NMR (100 MHz, CDCl3): δ 163.96, 163.51, 163.44, 159.45, 148.62, 144.56, 130.77, 130.58, 126.89, 125.93, 125.24, 123.80, 118.58, 118.26, 45.41, 45.21, 36.76, 32.13, 32.10, 31.83, 30.28, 29.88, 29.85, 29.83, 29.80, 29.78, 29.56, 29.53, 26.67, 26.63, 22.91, 22.88, 14.35

[0083] MALDI-TOF MS (Mw = 954.6704): found m / z = 955.4640 ([M]+)

[0084] (S5) The third compound (2.59 g, 2.72 mmol) obtained in step (S4) was dissolved in dry dichloromethane (10 mL), and bromine (Br 2 , 4.35 g, 27.18 mmol) was added under a nitrogen atmosphere; the mixture was heated to 60 °C and stirred for 15 hours. After the reaction, it was cooled to room temperature, brine was added, and it was extracted three times with dichloromethane; after the organic phases were combined, it was washed three times with water; then, with Na 2 SO4 Dry, and remove the solvent by rotary evaporation; the residue after removing the solvent is purified by silica gel column chromatography, and the mobile phase is a mixture of petroleum ether and dichloromethane (the volume ratio of petroleum ether to dichloromethane is 1:1); finally, an orange oily product is obtained: the target compound - a receptor unit with a skeleton containing a cyclic thiophene, bromination substitution at the 2-position of the thiophene, and an alkyl substitution on the side chain (1.83 g, yield 70%, and the 1H NMR spectrum is as Figure 4 shown).

[0085] 1H NMR (400 MHz, CDCl3): δ 8.87 (s, 1H), 8.78 (s, 2H), 4.15 (dd, J = 7.3, 3.3 Hz, 4H), 2.01 (q, J = 6.8 Hz, 2H), 1.58 (s, 1H), 1.47 - 1.15 (m, 81H), 0.85 (q, J = 6.9 Hz, 15H)

[0086] 13C NMR (100 MHz, CDCl3): δ 163.38, 163.23, 162.94, 162.83, 145.78, 142.17, 132.50, 130.95, 130.85, 126.62, 126.49, 125.61, 124.85, 123.22, 117.56, 116.88, 45.30, 45.15, 36.84, 36.79, 32.15, 32.12, 31.87, 31.79, 30.28, 29.90, 29.86, 29.81, 29.58, 29.56, 26.67, 26.59, 22.91, 22.90, 14.34

[0087] MALDI - TOF MS (Mw = 960.5413): found m / z = 962.2995 ([M + H]+)

[0088] Comparative Example 1

[0089] This comparative example provides a preparation method of a trimer compound, and its synthetic route is shown as follows:

[0090]

[0091] Dissolve BTT (150 mg, 0.25 mmol), the first compound prepared in Example 1 (900 mg, 0.79 mmol), Pd 2 (dba) 3(11 mg, 0.012 mmol) and tris(2-methylphenyl)phosphine (30 mg, 0.010 mmol) were added to a 100 mL two-necked round-bottom flask, and 20 mL of toluene was added under a nitrogen atmosphere; the resulting mixture was heated to 90 °C and stirred for 16 h. After the reaction was completed, it was cooled to room temperature, and toluene was removed using a rotary evaporator; after adding brine, the reaction product was extracted with dichloromethane; after drying, the solution was concentrated using a rotary evaporator; the residue was purified by silica gel column chromatography with a mobile phase of a mixture of petroleum ether and dichloromethane (volume ratio of petroleum ether to dichloromethane was 1:1), to obtain a black solid: NDI-BTT (yield was about 38%, and the 1H NMR spectrum was as shown in Figure 5 shown).

[0092] 1H NMR (400 MHz, CDCl3): δ 8.85 - 8.78 (m, 2H), 7.94 (s, 1H), 4.13 (d, J = 7.3 Hz, 4H), 2.01 (dp, J = 12.4, 6.3 Hz, 2H), 1.48 - 1.11 (m, 71H), 0.92 - 0.81 (m, 13H)

[0093] 13C NMR (100 MHz, CDCl3): δ 163.04, 162.80, 162.49, 152.36, 142.51, 142.10, 140.17, 136.08, 131.44, 130.65, 129.82, 128.01, 127.80, 126.76, 126.40, 126.12, 125.84, 125.47, 125.12, 123.20, 44.99, 36.64, 36.57, 31.90, 31.68, 31.62, 30.11, 30.02, 29.64, 29.58, 29.34, 29.31, 26.46, 26.42, 22.67, 14.10 MALDI-TOF MS (Mw = 1949.2712): found m / z = 1950.3798 ([M + H]+)

[0094] Example 2

[0095] This example provides a method for preparing a trimer compound, and its synthetic route is shown as follows:

[0096]

[0097] BT (124 mg, 0.32 mmol) and the target compound prepared in Example 1 (900 mg, 0.96 mmol) were added to a two-necked round-bottom flask, a magnetic stir bar was added, and under a nitrogen atmosphere, 2 drops of tri-n-octylmethylammonium chloride (Aliquat 336) and 30 mL of toluene were added; then 2 M potassium hydrogencarbonate solution (1.6 mL) was added, and the mixture was stirred at room temperature for 10 minutes. Subsequently, tetrakis(triphenylphosphine)palladium (20 mg, 0.016 mmol) was added; the resulting mixture was heated to 100 °C and reacted for 24 hours. After the reaction was completed, it was cooled to room temperature, and toluene was removed using a rotary evaporator; water was added, and the reaction product was extracted three times with dichloromethane; the organic phase was collected and dried with Na 2 SO 4 . After concentration, the residue was purified by silica gel column chromatography with a mobile phase of a mixture of petroleum ether and dichloromethane (volume ratio of petroleum ether to dichloromethane was 1:1), to obtain a black solid NTI-BT (yield was about 42%, and the 1H NMR spectrum was as shown in Figure 6 ).

[0098] 1H NMR (400 MHz, CDCl3): δ 8.99 (s, 1H), 7.87 (d, J = 108.7 Hz, 3H), 4.33 (dd, J = 26.7, 7.4 Hz, 4H), 2.33 - 2.14 (m, 2H), 1.77 - 1.46 (m, 21H), 1.34 (d, J = 32.6 Hz, 89H), 0.88 (h, J = 6.4 Hz, 23H)

[0099] 13C NMR (100 MHz, CDCl3): δ 163.22, 163.08, 162.56, 151.44, 149.18, 142.48, 128.90, 127.93, 126.12, 125.76, 124.94, 123.63, 118.04, 117.82, 45.46, 36.83, 36.72, 31.91, 31.87, 30.45, 30.36, 30.17, 29.81, 29.75, 29.65, 29.38, 29.31, 26.83, 26.62, 22.61, 22.57, 13.95

[0100] MALDI-TOF MS (Mw = 1897.2399): found m / z = 1899.2897 ([M + H]+)

[0101] Example 3

[0102] This example provides a method for preparing a trimer compound, and its synthetic route is shown in the following formula:

[0103]

[0104] Dissolve the target compound (900 mg, 0.94 mmol) prepared in Example 1 and BTT (146 mg, 0.23 mmol) in dry toluene (20 mL), and add Pd 2 (dba) 3 (11 mg, 0.012 mmol) and P(o-tol) 3 (29 mg, 0.094 mmol) under a nitrogen atmosphere; heat the resulting mixture to 90 °C and stir for 16 hours; after the reaction is complete, cool to room temperature, remove toluene using a rotary evaporator; add brine, and extract three times with dichloromethane. Combine the organic phases and wash three times with water; then, dry the solution with Na 2 SO 4 and remove the solvent by rotary evaporation; purify the residue after removing the solvent by silica gel column chromatography, with the mobile phase being a mixture of petroleum ether and dichloromethane (the volume ratio of petroleum ether to dichloromethane is 4:1); finally, obtain a dark red solid NTI-BTT (yield is about 40%, and the 1H NMR spectrum is as shown in Figure 7 ).

[0105] 1H NMR (400 MHz, CDCl3): δ 8.47 (d, J = 15.9 Hz, 1H), 8.27 (d, J = 21.4 Hz, 2H), 7.83 (s, 1H), 7.40 (s, 2H), 4.29 - 4.03 (m, 4H), 2.05 (d, J = 47.6 Hz, 2H), 1.57 - 1.14 (m, 81H), 0.85 (d, J = 7.0 Hz, 16H)

[0106] 13C NMR (100 MHz, CDCl3): δ 163.20, 162.91, 162.51, 162.24, 151.32, 149.41, 144.68, 143.53, 142.34, 138.16, 129.28, 128.96, 125.62, 124.84, 124.68, 124.39, 122.92, 118.29, 116.90, 116.04, 45.09, 36.89, 36.70, 31.93, 31.89, 31.74, 30.28, 30.19, 29.74, 29.67, 29.63, 29.60, 29.37, 29.33, 26.66, 26.47, 22.62, 13.98 MALDI-TOF MS (Mw = 2061.2153): found m / z = 2063.4934 ([M + H]+)

[0107] Comparative Example 2

[0108] This comparative example provides a method for preparing an organic field-effect transistor using a trimeric organic molecule NDI-BTT as a semiconductor transport layer, which specifically includes the following steps:

[0109] The organic field-effect transistor (OTFT) structure provided in this comparative example is a bottom-gate top-contact device, using Si / SiO 2 as the substrate (20 mm × 20 mm).

[0110] (A1) The substrate is cleaned with a mixed solution of H 2 SO 4 and H 2 O 2 (H 2 SO 4 : H 2 O 2 = 2:1 (volume ratio)), and then ultrasonically cleaned in deionized water and ethanol respectively to obtain a pretreated substrate;

[0111] (A2) After step (A1), the front side of the substrate is immersed in a toluene solution of octadecyltrichlorosilane (0.2 v / v%), and then placed at 120 °C for 3 hours to modify the surface, and then ultrasonically cleaned in n-hexane, isopropanol and chloroform respectively;

[0112] (A3) After step (A2), a chlorobenzene solution of NDI-BTT (5 mg / mL) is spin-coated (150 μL, which can be adjusted to 50 - 200 μL according to the actual situation) onto the front side of the substrate to form a thin film, and then the obtained device is subjected to a thermal annealing treatment at 60 °C;

[0113] (A4) After step (A3), a gold (Au) top-contact electrode is deposited by thermal evaporation (thickness of 30 nm, which can be adjusted to 28 - 35 mm according to the actual situation) on the front side of the substrate to obtain an organic field-effect transistor (the performance side view is as Figure 8 shown).

[0114] The field-effect performance of the device is measured using a Keithley S4200 SCS semiconductor characterization system. The saturation field-effect mobility (μ) is calculated from the average slope of the |I SD | 1 / 2 vs V g image of the gate voltage V g according to the following equation:

[0115] I SD = (W / 2L)C i μ(V g - V th ) 2

[0116] Among them, I SD is the drain current in the saturation region, W (1400 μm) and L (50 μm) are the width and length of the semiconductor channel respectively, C i (SiO 2 ) = 11.5 nF·cm-2 is the capacitance per unit area of the dielectric layer, V g and V th are the gate voltage and the threshold voltage respectively.

[0117] Table 1 Performance summary table of NDI-BTT prepared in Comparative Example 1

[0118] Organic molecule type <![CDATA[Electron mobility (cm 2 V -1 s -1 )]]> Threshold voltage (V) On-off ratio NDI-BTT 0.03 0～15 <![CDATA[10 3 >

[0119] Example 4

[0120] This example provides a method for preparing an organic field-effect transistor using a trimeric organic molecule NTI-BT as a semiconductor transport layer, which specifically includes the following steps:

[0121] The organic field-effect transistor (OTFT) structure provided in this example is a bottom-gate top-contact type device, using Si / SiO 2 as the substrate (20 mm × 20 mm).

[0122] (A1) The substrate is cleaned with a mixed solution of H 2 SO 4 and H 2 O 2 (H 2 SO 4 : H 2 O 2 = 2:1 (volume ratio)), and then ultrasonically cleaned in deionized water and ethanol respectively to obtain a pretreated substrate;

[0123] (A2) After step (A1) is completed, the front side of the substrate is immersed in a toluene solution of octadecyltrichlorosilane (0.2 v / v%), and then placed at 120 °C for 3 hours to modify the surface, and then ultrasonically cleaned in n-hexane, isopropanol and chloroform respectively;

[0124] (A3) After step (A2) is completed, a chlorobenzene solution of NTI-BT (5 mg / mL) is spin-coated (150 μL, which can be adjusted to 50 - 200 μL according to the actual situation) onto the front side of the substrate to form a thin film, and then the obtained device is subjected to a thermal annealing treatment at 60 °C;

[0125] (A4) After step (A3) is completed, a gold (Au) top-contact electrode is deposited by thermal evaporation (thickness 30 nm, which can be adjusted to 28 - 35 mm according to the actual situation) on the front side of the substrate to obtain an organic field-effect transistor (the performance side view is asFigure 8 as shown

[0126] The field-effect performance of the device was measured using a Keithley S4200 SCS semiconductor characterization system. The saturation field-effect mobility (μ) was calculated from the average slope of the |I SD | 1 / 2 vs V g versus gate voltage V g of the graph, according to the following equation:

[0127] I SD = (W / 2L)C i μ(V g - V th ) 2

[0128] where I SD is the drain current in the saturation region, W (1400 μm) and L (50 μm) are the width and length of the semiconductor channel, respectively, C i (SiO 2 ) = 11.5 nF·cm-2 is the capacitance per unit area of the dielectric layer, V g and V th are the gate voltage and threshold voltage, respectively.

[0129] Table 2 Summary of the performance of NTI-BT prepared in Example 2

[0130] Organic molecule type <![CDATA[Electron mobility (cm 2 V -1 s -1 )]]> Threshold voltage (V) On-off ratio NTI-BT 0.004 0～17 <![CDATA[10 4 >

[0131] Example 5

[0132] This example provides a method for preparing an organic field-effect transistor using a trimeric organic molecule NTI-BTT as the semiconductor transport layer, which specifically includes the following steps:

[0133] The organic field-effect transistor (OTFT) structure provided in this example is a bottom-gate top-contact device, using Si / SiO 2 as the substrate (20 mm × 20 mm).

[0134] (A1) The substrate was cleaned with a mixed solution of H 2 SO 4 and H 2 O 2 (H 2 SO 4 : H 2 O 2 = 2:1 (volume ratio)), and then ultrasonically cleaned in deionized water and ethanol respectively to obtain a pretreated substrate;

[0135] (A2) After step (A1) is completed, immerse the front side of the substrate in a toluene solution of octadecyltrichlorosilane (0.2 v / v%), then place it at 120 °C for 3 hours to modify the surface, and then ultrasonically clean it in n-hexane, isopropyl alcohol, and chloroform respectively;

[0136] (A3) After step (A2) is completed, use a chlorobenzene solution of NTI-BTT (5 mg / mL), spin-coat it (150 μL, which can be adjusted to 50 - 200 μL according to the actual situation) onto the front side of the substrate to form a thin film, and then perform a thermal annealing treatment on the obtained device at 60 °C;

[0137] (A4) After step (A3) is completed, a gold (Au) top contact electrode is deposited by thermal evaporation (with a thickness of 30 nm, which can be adjusted to 28 - 35 mm according to the actual situation) on the front side of the substrate to obtain an organic field-effect transistor (the performance side view is as Figure 8 ) as shown.

[0138] Use a Keithley S4200 SCS semiconductor characterization system to measure the field-effect performance of the device. The saturation field-effect mobility (μ) is calculated from the average slope of the |I SD | 1 / 2 vs V g image of the gate voltage V g according to the following equation:

[0139] I SD =(W / 2L)C i μ(V g -V th ) 2

[0140] where I SD is the drain current in the saturation region, W (1400 μm) and L (50 μm) are the width and length of the semiconductor channel respectively, C i (SiO 2 ) = 11.5 nF·cm-2 is the capacitance per unit area of the dielectric layer, V g and V th are the gate voltage and threshold voltage respectively.

[0141] Table 3 Summary of the performance of NTI-BTT prepared in Example 3

[0142] Organic molecule type <![CDATA[Electron mobility (cm 2 V -1 s -1 )]]> Threshold voltage (V) On-off ratio NTI-BTT 0.13 0～15 <![CDATA[10 4 >

[0143] The above description of the embodiments is provided to enable those of ordinary skill in the art to understand and use the invention. 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 efforts. Therefore, the present invention is not limited to the above embodiments, and all improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the interpretation of the present invention should be within the protection scope of the present invention.

Claims

1. An acceptor unit having a skeleton containing cyclic thiophene, bromination substitution at the 2-position of thiophene, and substitution of a side chain alkyl, characterized in that: The chemical structural formula of the receptor unit is shown in formula (I): wherein m and n are independently selected from integers of 0-4, and x and y are independently selected from integers of 1-20.

2. A method for preparing an acceptor unit having a skeleton containing cyclic thiophene, bromination substitution at the 2-position of thiophene, and side chain alkyl substitution as claimed in claim 1, characterized in that: The following steps are involved: (S1) mixing 1,4,5,8-naphthalenetetracarboxylic anhydride, 1,3-dibromo-5,5-dimethylthiazoline and concentrated sulfuric acid and performing bromination reaction, followed by post-treatment to obtain a crude product: NDA-Br; (S2) mixing the NDA-Br, 2-n-octyl-1-dodecylamine and acetic acid prepared in step (S1) and performing a branching reaction, followed by post-treatment to obtain a first compound; (S3) mixing the first compound prepared in step (S2), a palladium catalyst, tri(o-methylphenyl)phosphine, a copper catalyst, triethylamine and trimethylsilane, and performing a Sonogashira coupling reaction, followed by post-treatment to obtain a second compound; (S4) mixing the second compound prepared in step (S3), sodium sulfide and ethanol, performing a thiophene cyclization reaction, and performing post-treatment to obtain a third compound; (S5) mixing the third compound prepared in step (S4), dichloromethane and bromine and performing a bromination reaction, followed by post-treatment to obtain an acceptor unit having a skeleton containing a cyclic thiophene, a brominated substitution at the 2-position of thiophene, and a side chain alkyl substitution; Wherein, the chemical structural formula of NDA-Br is shown in formula (II), the chemical structural formula of the first compound is shown in formula (III), the chemical structural formula of the second compound is shown in formula (IV), and the chemical structural formula of the third compound is shown in formula (V): In formula (III), formula (IV) and formula (V), m is selected from an integer of 0 to 4, n is selected from an integer of 0 to 4, x is selected from an integer of 1 to 20, and y is selected from an integer of 1 to 20.

3. The method for preparing an acceptor unit having a skeleton containing cyclic thiophene, bromination substitution at the 2-position of thiophene, and substitution of a side chain alkyl group according to claim 2, characterized in that: In step (S1), the ratio of 1,4,5,8-naphthalenetetracarboxylic anhydride, 1,3-dibromo-5,5-dimethylthiazoline and concentrated sulfuric acid is 1 mmol: 0.5-2.5 mmol: 60-240 mL; During the bromination reaction, the temperature is 60-120°C and the time is 2-24h; In step (S2), the ratio of NDA-Br, 2-n-octyl-1-dodecylamine and acetic acid is 1-7 mmol: 1 mmol: 2.5-30 mL; During the branching reaction, the temperature is 30-150°C and the time is 2-12 hours.

4. The method for preparing an acceptor unit having a skeleton containing cyclic thiophene, bromination substitution at the 2-position of thiophene, and substitution of a side chain alkyl group according to claim 2, characterized in that: In step (S3), the palladium catalyst is selected from one or more of bis(triphenylphosphine)dichloroplatinum, trisdibenzylideneacetone dipalladium, palladium acetate, tetrakis(triphenylphosphine)palladium, bis(acetylacetone)palladium, dichloro(ethylenediamine)palladium or bis(triphenylphosphine)diacetate palladium; The copper catalyst is selected from one or more of copper sulfide, cuprous sulfide or cuprous iodide; The ratio of the first compound, palladium catalyst, tri(o-methylphenyl)phosphine, copper catalyst, anhydrous triethylamine and trimethylsilane is 5.525mmol: 0.1-0.3mmol: 0.1-0.5mmol: 0.1-0.5mmol: 10-15mL: 2-20mmol; The Sonogashira coupling reaction is carried out under a nitrogen atmosphere, at a temperature of 60 to 150° C., and for a time of 2 to 12 hours.

5. The method for preparing an acceptor unit having a skeleton containing cyclic thiophene, bromination substitution at the 2-position of thiophene, and substitution of a side chain alkyl group according to claim 2, characterized in that: In step (S4), the usage ratio of the second compound, sodium sulfide and ethanol is 4.53 mmol: 10-15 mmol: 20-60 mL; The thiophene cyclization reaction is carried out under a nitrogen atmosphere at a temperature of 60 to 120° C. for a time of 6 to 24 hours; In step (S5), the usage ratio of the third compound, dichloromethane and bromine is 2.72mmol:10mL:20-30mmol; The bromination reaction is carried out under a nitrogen atmosphere, at a temperature of 30 to 90° C., and for a time of 2 to 15 hours.

6. Use of the acceptor unit having a skeleton containing cyclic thiophene, bromination substitution at the 2-position of thiophene, and substitution of side chain alkyl as claimed in claim 1 in the preparation of n-type polymer organic molecules.

7. A method for preparing an n-type polymer organic molecule, characterized in that: The following steps are involved: The first raw material, the receptor unit having a skeleton containing a ring-containing thiophene, a thiophene 2-position bromide substitution, and a side chain alkyl substitution according to claim 1, a palladium catalyst, an initiator, and a solvent are mixed and then subjected to a coupling reaction, and post-processed to obtain an n-type multimeric organic molecule; The first raw material is selected from one of 2,1,3-benzothiadiazole-4,7-bis(boronic acid pinyl) or 4,7-bis(5-(trimethyltinyl)thiophen-2-yl)benzo[c][1,2,5]thiadiazole.

8. The method for preparing an n-type polymer organic molecule according to claim 7, characterized in that: The molar ratio of the first raw material, the acceptor unit having a skeleton containing a cyclic thiophene, a bromination substitution at the 2-position of thiophene, a side chain alkyl substitution, and the palladium catalyst is 0.2-1:0.2-1:0.01-0.2; During the coupling reaction, the temperature is 30-150°C and the time is 6-24 hours.

9. An n-type polymer organic molecule, characterized in that: The n-type polymer organic molecule is prepared by the method according to any one of claims 7 to 8.

10. Use of the n-type polymer organic molecule according to claim 9 in preparing an organic optoelectronic device.

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