Conjugated small molecule photoresist, preparation method thereof and application of conjugated small molecule photoresist in organic thin film transistor

Abstract

The invention belongs to the technical field of synthesis and application of organic semiconductor materials, and particularly relates to conjugated small molecule photoresist, a preparation method thereof and application of the conjugated small molecule photoresist in an organic thin film transistor. A compound of an alkyl chain with a photoreaction functional group is introduced to benzothienobenzothiophene, a polymerization reaction can be carried out under the assistance of a cross-linking agent by introducing an acetylene group, the polymerization reaction can be carried out by introducing diacetylene, meanwhile, the overall stacking structure of a BTBT core is not changed, and a channel is provided for efficient transmission of current carriers. Therefore, the material combines the functions of organic semiconductor molecules and traditional photoresist, and a new thought is provided for the design of the conjugated small-molecule semiconductor photoresist.

Description

Technical Field

[0001] The invention belongs to the technical field of synthesis and application of organic semiconductor materials, and in particular relates to a conjugated small molecule photoresist and a preparation method thereof and application in an organic thin film transistor. Background Art

[0002] As an emerging electronic device, organic thin film transistors (OTFTs) are widely used in sensors, photodetectors, radio frequency identification (RFID) tags, electronic paper, skin-integrated electronic devices, and artificial synapses. Organic semiconductor materials have attracted more and more attention and research due to their controllable molecular structure, high carrier mobility, and easy modification. The semiconductor industry uses photolithography as the most widely used patterning technology with high precision, high reliability, and high integration, but it is a challenge to directly use photolithography to process conjugated semiconductors into electronic devices. At present, there are many studies on polymer semiconductor photoresists, mainly focusing on: 1. Mixing with crosslinkers. 2. Introducing photoresponsive groups into the side chains of polymers, but the carrier mobility exhibited is low. The preparation of organic small molecule semiconductor patterning relies on expensive equipment and complex preparation processes such as physical vapor deposition, inkjet printing, and substrate surface wettability adjustment.

[0003] Based on the above background technology, a small molecule semiconductor photoresist material suitable for OTFT manufacturing is developed, which has important technical and application value. Summary of the invention

[0004] In view of the problems and shortcomings in the prior art, the purpose of the present invention is to provide a conjugated small molecule photoresist and a preparation method thereof and application in organic thin film transistors.

[0005] To achieve the purpose of the invention, the technical solution adopted by the present invention is as follows:

[0006] The first aspect of the present invention provides a conjugated small molecule photoresist, the structural formula of which is shown in Formula 1 or Formula 2:

[0007]

[0008] Among them, m=4 or 5; n=0 or 2.

[0009] The second aspect of the present invention provides a method for preparing the above-mentioned conjugated small molecule photoresist, comprising the following steps:

[0010] (1) Preparation of Compound C m BTBT-2Si:

[0011] Add trimethylsilyl acetylene to solvent A, cool to -78-80°C, add n-butyl lithium, stir for 1-1.5h, then add hexamethylphosphoramide and compound C in sequence mBTBT-2Br, heated to room temperature and stirred for 16-18h, then added with ammonium chloride solution to quench the reaction, and compound C was obtained after separation and purification. m BTBT-2Si;

[0012] The compound C m BTBT-2Br and compound C m The structural formula of BTBT-2Si is as follows:

[0013]

[0014] (2) Preparing a conjugated small molecule photoresist having a structural formula as shown in Formula 1:

[0015] Compound C m BTBT-2Si is added to solvent B, and potassium carbonate is added, and the mixture is stirred and reacted at 40-50° C. After the reaction is completed, a conjugated small molecule photoresist having a structural formula as shown in Formula 1 is obtained by separation and purification, wherein m=4 or 5;

[0016] (3) Preparing a conjugated small molecule photoresist having a structural formula as shown in Formula 2:

[0017] A conjugated small molecule photoresist with a structural formula as shown in Formula 1 is added to a solvent C, and then cuprous iodide and compound A are added, and the reaction is stirred for 12 to 14 hours under an inert gas atmosphere, and an aqueous solution of ammonium chloride is added to quench the reaction, and a conjugated small molecule photoresist with a structural formula as shown in Formula 2 is obtained after separation and purification, wherein m=4 or 5, and n=0 or 2;

[0018] The structural formula of compound A is as follows:

[0019]

[0020] Where n=0 or 2.

[0021] Furthermore, in step (2), the compound C m The molar ratio of BTBT-2Si to potassium carbonate is 1:(5-5.5); the molar ratio of the conjugated small molecule photoresist having the structural formula shown in Formula 1 in step (3) to cuprous iodide and compound A is 1:(0.25-0.3):(5-5.5).

[0022] Further, in step (1), the compound C m The molar ratio of BTBT-2Br to trimethylsilylacetylene, n-butyl lithium and hexamethylphosphoramide is 1:(5-5.5):(5-5.5):(5-5.5).

[0023] Furthermore, the solvent A in step (1) is tetrahydrofuran, and the separation and purification process is: extracting the aqueous phase with dichloromethane, collecting the organic phase for drying, filtering after drying, concentrating the filtrate and separating the obtained crude product by column chromatography, and the eluent is ethyl acetate:n-hexane in a volume ratio of 1:50.

[0024] Furthermore, the solvent B in step (2) is methanol; the separation and purification process is: pouring the reaction solution into water, extracting the aqueous phase with dichloromethane, collecting the organic phase and drying it, filtering and concentrating it after drying, and recrystallizing the obtained crude product, and the solvent is dichloromethane:n-hexane in a volume ratio of 1:5.

[0025] Furthermore, in step (3), the solvent C is pyrrolidine, and the separation and purification process is: extracting the aqueous phase with dichloromethane, collecting the organic phase for drying, filtering after drying, concentrating the filtrate and separating the obtained crude product by column chromatography, and the eluent is ethyl acetate:n-hexane in a volume ratio of 1:50.

[0026] Furthermore, the compound C m The preparation method of BTBT-2Br is as follows: under an inert gas atmosphere, compound C m BTBT-2acyl is added to solvent D, and sodium borohydride and aluminum chloride are added after cooling to 0°C, and then the reaction solution is heated to 90-95°C for 12-14 hours. After the reaction is completed, the compound C is obtained by separation and purification. m BTBT-2Br;

[0027] Wherein, the compound C m The structural formula of BTBT-2acyl is as follows:

[0028]

[0029] Furthermore, the compound C m The molar ratio of BTBT-2acyl, sodium borohydride and aluminum chloride is 1:(10-11):(5-5.5).

[0030] Furthermore, the solvent D is tetrahydrofuran, and the separation and purification process is: pouring the reaction solution into a mixture of dichloromethane and water, collecting the organic phase and drying it, filtering it after drying, concentrating the filtrate and separating the obtained crude product by column chromatography, and the eluent is a volume ratio of dichloromethane:n-hexane = 1:(1~5).

[0031] Furthermore, the compound C mThe preparation method of BTBT-2acyl is as follows: adding compound BTBT to solvent E, cooling to -10 to -15°C, adding aluminum chloride, further cooling to -80 to -85°C, adding compound B, keeping the temperature to react overnight, and after the reaction is completed, separating and purifying to obtain compound C m BTBT-2acyl;

[0032] The structural formulas of the compound BTBT and compound B are as follows:

[0033]

[0034] Furthermore, the molar ratio of the compound BTBT, aluminum chloride and compound B is 1:(5-5.5):(5-5.5).

[0035] Furthermore, the solvent E is dichloromethane, and the separation and purification process is: pouring the reaction solution into water, extracting the aqueous phase with dichloromethane, collecting the organic phase and washing the organic phase with water again, drying the organic phase and drying it, filtering and concentrating after drying, and recrystallizing the obtained crude product using toluene.

[0036] The third aspect of the present invention provides a use of the above-mentioned conjugated small molecule photoresist in the preparation of an organic thin film transistor.

[0037] Furthermore, the organic thin film transistor comprises, from bottom to top, a substrate, a gate electrode, a dielectric layer, an organic semiconductor thin film and a source-drain electrode layer, and the organic semiconductor thin film is prepared by any one of the conjugated small molecule photoresists described in claim 1.

[0038] Furthermore, the dielectric layer is a polymer brush modified dielectric layer, and the specific process is: the dielectric layer is hydroxylated, then placed in a 7-octenyltrimethoxysilane solution and heated at 60-70°C for 10-12 hours, and then placed in a polystyrene thiol capping solution and illuminated for 30-60 minutes, that is, the polymer brush is modified on the dielectric layer.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The present invention successfully prepared a conjugated small molecule photoresist ([1]benzothieno[3,2-b]benzothiophene photoresist), that is, a compound with an alkyl chain having a photoreactive functional group introduced into benzothienobenzothiophene, which can undergo polymerization reaction with the assistance of a crosslinking agent by introducing an acetylene group. The introduction of diacetylene will cause polymerization reaction itself, while not changing the overall stacking structure of the BTBT core, providing a channel for efficient carrier transmission. Therefore, this type of material combines the functions of organic semiconductor molecules and traditional photoresists, providing a new idea for the design of small molecule semiconductor photoresists.

[0041] 2. The self-polymerization mechanism of the small molecule photoresist of the present invention can achieve fine patterning and accurately transfer the pattern on the mask to the substrate, which is conducive to the miniaturization and high performance of the device. The covalent bonds formed during the self-polymerization process will enhance the strength and environmental stability of the material, help maintain the integrity of the pattern and extend the service life of the device.

[0042] 3. The self-polymerization patterning process of the small molecule photoresist of the present invention is gentle and simple, reducing the dependence on high temperature or harmful chemicals, reducing process complexity and cost, conforming to the trend of green manufacturing, and suitable for large-area printing and flexible electronic device manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Compound C 5 BTBT-2acyl 1 H NMR spectrum;

[0044] Figure 2 Compound C 5 BTBT-2acyl 13 C NMR spectrum;

[0045] Figure 3 Compound C 5 HRMS spectrum of BTBT-2acyl;

[0046] Figure 4 Compound C 6 BTBT-2acyl 1 H NMR spectrum;

[0047] Figure 5 Compound C 6 BTBT-2acyl 13 C NMR spectrum;

[0048] Figure 6 Compound C 6 HRMS spectrum of BTBT-2acyl;

[0049] Figure 7 Compound C 5 BTBT-2Br 1 H NMR spectrum;

[0050] Figure 8 Compound C 5 BTBT-2Br 13 C NMR spectrum;

[0051] Fig. 9 Compound C 5 HRMS spectrum of BTBT-2Br;

[0052] Fig.10 Compound C 6 BTBT-2Br 1 H NMR spectrum;

[0053] Fig.11 Compound C 6 BTBT-2Br 13 C NMR spectrum;

[0054] Fig.12 Compound C 6 HRMS spectrum of BTBT-2Br;

[0055] Fig.13 Compound C 5 BTBT-2Si 1 HNMR spectrum;

[0056] Fig.14 Compound C 5 BTBT-2Si 13 C NMR spectrum;

[0057] Fig.15 Compound C 5 HRMS spectrum of BTBT-2Si;

[0058] Fig.16 Compound C 6 BTBT-2Si 1 HNMR spectrum;

[0059] Fig.17 Compound C 6 BTBT-2Si 13 C NMR spectrum;

[0060] Fig.18 Compound C 6 HRMS spectrum of BTBT-2Si;

[0061] Fig.19 Compound C 5 BTBT-2y 1 H NMR spectrum;

[0062] Fig. 20 Compound C 5 BTBT-2y 13 C NMR spectrum;

[0063] Fig.21 Compound C 5 HRMS spectrum of BTBT-2y;

[0064] Fig. 22 Compound C 6 BTBT-2y 1 H NMR spectrum;

[0065] Fig.23 Compound C 6 BTBT-2y 13 C NMR spectrum;

[0066] Fig.24 Compound C 6 HRMS spectrum of BTBT-2y;

[0067] Fig.25 Compound C 5 BTBT-2yyC1 1 H NMR spectrum;

[0068] Fig.26 Compound C 5 BTBT-2yyC1 13 C NMR spectrum;

[0069] Fig. 27 Compound C 5 HRMS spectrum of BTBT-2yyC1;

[0070] Fig.28 Compound C 5 BTBT-2yyC3 1 H NMR spectrum;

[0071] Fig.29 Compound C 5 BTBT-2yyC3 13 C NMR spectrum;

[0072] Fig.30 Compound C 5 HRMS spectrum of BTBT-2yyC3;

[0073] Fig.31 Compound C 6 BTBT-2yyC3 1 H NMR spectrum;

[0074] Fig.32 Compound C 6 BTBT-2yyC3 13 C NMR spectrum;

[0075] Fig.33 Compound C 6 HRMS spectrum of BTBT-2yyC3;

[0076] Fig.34 The patterned organic semiconductor thin film image prepared in step S2 of Example 17;

[0077] Fig.35 The patterned organic semiconductor thin film image prepared in step S2 of Example 18;

[0078] Fig.36 The patterned organic semiconductor thin film image prepared in step S2 of Example 19;

[0079] Fig.37 The patterned organic semiconductor thin film image prepared in step S2 of Example 20;

[0080] Fig.38 The polarization morphology of the organic semiconductor film obtained in step S2 of Example 12;

[0081] Fig.39 The polarization morphology of the organic semiconductor film obtained in step S2 of Example 14;

[0082] Fig.40 This is an atomic force microscope test image of the organic semiconductor film obtained in step S2 of Example 12;

[0083] Fig.41 This is an atomic force microscope test image of the organic semiconductor film obtained in step S2 of Example 14;

[0084] Fig.42 The X-ray diffraction test results of the organic semiconductor thin film obtained in step S2 of Example 12 and Example 14;

[0085] Fig.43 The transfer and output characteristic curves of the organic thin film transistor prepared in Example 12 and the carrier mobility change diagram at different scraping speeds;

[0086] Fig.44 The transfer and output characteristic curves of the organic thin film transistor prepared in Example 14 and the carrier mobility change diagram at different scraping speeds;

[0087] Fig.45 The carrier mobility results of the patterned organic thin film transistors prepared in Examples 17-19;

[0088] Fig.46 This is a statistical histogram of the carrier mobility exhibited by 36 patterned devices prepared in Example 20. DETAILED DESCRIPTION

[0089] The following examples are only for further explanation of the present invention. It should be noted that all technical and scientific terms used in the present invention have the same meaning as in the technical field to which the present invention belongs unless otherwise specified. The experimental methods in the following examples without specifying specific conditions are all based on conventional techniques in the technical field, or according to the conditions recommended by the manufacturer; the reagents or instruments used without specifying the manufacturer are all conventional products that can be purchased from the market, or can be prepared according to conventional techniques in the technical field.

[0090] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0091] Example 1

[0092] A compound C 5 The preparation method of BTBT-2acyl comprises the following steps:

[0093]

[0094] Compound BTBT (5 g, 20.8 mmol) was added to dichloromethane (250 mL), and aluminum chloride (15.2 g, 114.4 mmol, 5.5 eq) was added at -10 °C. After cooling to -84 °C, 5-bromovaleryl chloride (20.7 g, 104 mmol, 5 eq) was added dropwise, and the temperature was kept at -84 °C overnight for reaction. After the reaction was completed, the reaction solution was poured into deionized water (200 mL), and the aqueous phase was extracted with dichloromethane (3×200 mL) and the organic layer was collected. The organic layer was then washed with deionized water (200 mL) and dried with anhydrous sodium sulfate. The organic solution was evaporated under reduced pressure to remove the solvent to obtain a solid, which was recrystallized using toluene to obtain a light yellow solid product (yield of 51.8%), named C 5 BTBT-2acyl.

[0095] This example also provides compound C prepared by the above method 5 BTBT-2acyl.

[0096] The prepared compound C 5 BTBT-2acyl was subjected to NMR analysis. 1 H NMR spectrum Figure 1 As shown, 13 C NMR spectrum Figure 2 As shown. At the same time, compound C 5 BTBT-2acyl was subjected to mass spectrometry analysis (mass spectrometry results are shown in Figure 3 HRMS: [M+H] + C24 H 22 Br 2 O 2 S 2 , calculated to be 564.9506, found to be 566.0633. The above results confirm that the obtained product is the target product.

[0097] Example 2

[0098] A compound C 6 The preparation method of BTBT-2acyl is basically the same as that of Example 1, except that 5-bromohexanoyl chloride in Example 1 is replaced by 6-bromohexanoyl chloride (22.2 g, 104 mmol, 5 eq); Compound C is prepared 6 The yield of BTBT-2acyl was 60.2%.

[0099] Preparation of Compound C 6 The reaction formula of BTBT-2acyl is as follows:

[0100]

[0101] This example also provides compound C prepared by the above method 6 BTBT-2acyl.

[0102] The prepared compound C 6 BTBT-2acyl was subjected to NMR analysis. 1 H NMR spectrum Figure 4 As shown, 13 C NMR spectrum Figure 5 As shown. At the same time, compound C 6 BTBT-2acyl was subjected to mass spectrometry analysis (mass spectrometry results are shown in Figure 6 HRMS: [M+H] + C 26 H 26 Br 2 O 2 S 2 , calculated to be 592.9819, found to be 592.1032. The above results confirm that the obtained product is the target product.

[0103] Example 3

[0104] A compound C 5 The preparation method of BTBT-2Br comprises the following steps:

[0105]

[0106] Under nitrogen atmosphere, compound C prepared in Example 1 was 5BTBT-2acyl (3g, 5.3mmol) was added to tetrahydrofuran (75mL), and then sodium borohydride (2g, 53mmol, 10eq) and aluminum chloride (3.5g, 26.5mmol, 5eq) were added at 0°C to obtain a mixture, which was heated to 90°C and kept under reflux for 12 hours. After the reaction, the reaction solution was poured into a mixture of 300mL of dichloromethane and 150mL of deionized water, the reaction solution was extracted, and the organic solvent layer was collected. Anhydrous sodium sulfate was added to the collected organic solvent layer for drying, and the mixture was filtered after drying. The filtrate was collected and evaporated to dryness to obtain a crude product. The crude product was dissolved in dichloromethane, and then purified by chromatography on a silica gel column. The eluent was collected with a volume ratio of dichloromethane: n-hexane = 1:5 to 1:1. The solvent was removed by evaporation under reduced pressure to obtain a bright white solid product (yield 70%), named C 5 BTBT-2Br.

[0107] This example also provides compound C prepared by the above method 5 BTBT-2Br.

[0108] The prepared compound C 5 BTBT-2Br was subjected to NMR analysis. 1 H NMR spectrum Figure 7 As shown, 13 C NMR spectrum Figure 8 As shown. At the same time, the prepared compound C 5 BTBT-2Br was subjected to mass spectrometry analysis (mass spectrometry results are shown in Fig. 9 HRMS: [M+H] + C 24 H 26 Br 2 S 2 The calculated value was 536.9921, and the found value was 538.0633. The above results confirmed that the obtained product was the target product.

[0109] Example 4

[0110] A compound C 6 The preparation method of BTBT-2Br is basically the same as that of Example 3, except that: Compound C in Example 3 is 5 BTBT-2acyl was replaced by compound C 6 BTBT-2acyl (3 g, 5 mmol); Compound C 6 The yield of BTBT-2Br was 75%.

[0111] Preparation of Compound C 6 The reaction formula of BTBT-2Br is as follows:

[0112]

[0113] This example also provides compound C prepared by the above method 6 BTBT-2Br.

[0114] The prepared compound C 6 BTBT-2Br was subjected to NMR analysis. 1 HNMR spectrum Fig.10 As shown, 13 C NMR spectrum Fig.11 As shown. At the same time, compound C 6 BTBT-2acyl was subjected to mass spectrometry analysis (mass spectrometry results are shown in Fig.12 HRMS: [M+H] + C 26 H 30 Br 2 S 2 Calculated 565.0234, found 566.1167. The above results confirm that the obtained product is the target product.

[0115] Example 5

[0116] A compound C 5 The preparation method of BTBT-2Si comprises the following steps:

[0117]

[0118] Dissolve trimethylsilyl acetylene (913.4 mg, 9.3 mmol, 5 eq) in tetrahydrofuran (20 mL), cool to -78 °C, stir for 5 minutes, then add n-butyl lithium (1.6 M hexane solution, 5.8 mL, 9.3 mmol, 5 eq) dropwise over 20 minutes, stir at -78 °C for 1 hour, then add hexamethylphosphoramide (1.6 g, 9.3 mmol, 5 eq) dropwise. Finally, add C prepared in Example 3 dropwise at -78 °C. 5BTBT-2Br (1g, 1.86mmol, 1eq) in THF (20mL). The resulting white solution was stirred at -78°C for 10 minutes, and then returned to room temperature and stirred for 16 hours. After the reaction was completed, it was quenched with saturated aqueous ammonium chloride solution (50mL), the aqueous phase was extracted with dichloromethane (3×100mL), the organic solvent layer was collected, anhydrous sodium sulfate was added to the collected organic solvent layer for drying, and after drying, it was filtered, the filtrate was collected, and the filtrate was evaporated to dryness to obtain a crude product. The crude product was dissolved in dichloromethane, an equal amount of silica gel powder was added, and the solvent was removed by evaporation under reduced pressure. It was added to a silica gel column for chromatography purification, and the eluent was collected. The eluent was evaporated under reduced pressure to remove the solvent to obtain a white solid product (yield 26.8%), named C 5 BTBT-2Si.

[0119] This example also provides compound C prepared by the above method 5 BTBT-2Si.

[0120] The prepared compound C 5 BTBT-2Si was subjected to NMR analysis. 1 H NMR spectrum Fig.13 As shown, 13 C NMR spectrum Fig.14 As shown. At the same time, the prepared compound C 5 BTBT-2Si was subjected to mass spectrometry analysis (mass spectrometry results are shown in Fig.15 HRMS: [MH] - C 34 H 44 S 2 Si 2 Calculated 571.2345, found 571.2318. The above results confirm that the obtained product is the target product.

[0121] Example 6

[0122] A compound C 6 The preparation method of BTBT-2Si is basically the same as that of Example 5, except that: Compound C in Example 5 is 5 BTBT-2Br replaced by compound C 6 BTBT-2Br (1 g, 1.8 mmol, 1 eq); Compound C 6 The yield of BTBT-2Si was 24.1%.

[0123] Preparation of Compound C 6 The reaction formula of BTBT-2Si is as follows:

[0124]

[0125] This example also provides compound C prepared by the above method 6 BTBT-2Si.

[0126] The prepared compound C 6 BTBT-2Si was subjected to NMR analysis. 1 H NMR spectrum Fig.16 As shown, 13 C NMR spectrum Fig.17 As shown. At the same time, the prepared compound C 6 BTBT-2Si was subjected to mass spectrometry analysis (mass spectrometry results are shown in Fig.18 HRMS:[M] + C 36 H 48 S 2 Si 2 Calculated 600.2736, found 600.5810. The above results confirm that the obtained product is the target product.

[0127] Example 7

[0128] A conjugated small molecule photoresist C 5 The preparation method of BTBT-2y comprises the following steps:

[0129]

[0130] The C prepared in Example 5 5 BTBT-2Si (200 mg, 0.35 mmol, 1 eq) was added to methanol (5 mL), and anhydrous potassium carbonate (242 mg, 1.75 mmol, 5 eq) was added to the mixture. The resulting solution was stirred at 40 ° C overnight. After the reaction was completed, the mixture was poured into deionized water (20 mL), the aqueous phase was extracted with dichloromethane (3×20 mL), and the organic layer was collected. Anhydrous sodium sulfate was added to the collected organic solvent layer for drying. After drying, the filtrate was collected and evaporated to dryness to obtain a crude product. The crude product was recrystallized using a solvent with a volume ratio of dichloromethane: n-hexane = 1:5, and a white solid product was obtained by filtration (yield 89.6%), namely [1] benzothieno [3,2-b] benzothiophene conjugated small molecule photoresist, named C 5 BTBT-2y.

[0131] This embodiment also provides a conjugated small molecule photoresist C prepared by the above method. 5 BTBT-2y.

[0132] For the preparation of C 5BTBT-2y was subjected to NMR analysis. 1 H NMR spectrum Fig.19 As shown, 13 C NMR spectrum Fig. 20 As shown. 5 BTBT-2y was subjected to mass spectrometry analysis (mass spectrometry results are shown in Fig.21 HRMS: [MH] - C 28 H 28 S 2 Calculated 427.1554, found 427.2353. The above results confirm that the obtained product is the target product.

[0133] Example 8

[0134] A conjugated small molecule photoresist C 6 The preparation method of BTBT-2y is basically the same as that of Example 7, except that: 5 BTBT-2Si replaced by C 6 BTBT-2Si (200mg, 0.33mmol, 1eq); C 6 The yield of BTBT-2y was 91.7%.

[0135] Preparation of conjugated small molecule photoresist C 6 The reaction formula of BTBT-2y is as follows:

[0136]

[0137] This embodiment also provides a conjugated small molecule photoresist C prepared by the above method. 6 BTBT-2y.

[0138] C 6 BTBT-2y was subjected to NMR analysis. 1 H NMR spectrum Fig. 22 As shown, 13 C NMR spectrum Fig.23 As shown. 6 BTBT-2y was subjected to mass spectrometry analysis (mass spectrometry results are shown in Fig.24 HRMS:[M] + C 30 H 32 S 2 Calculated 456.1945, found 456.4349. The above results confirm that the obtained product is the target product.

[0139] Example 9

[0140] A conjugated small molecule photoresist C5 The preparation method of BTBT-2yyC1 comprises the following steps:

[0141]

[0142] At 0°C, the C prepared in Example 7 5 BTBT-2y (100 mg, 0.23 mmol, 1 eq) was dissolved in pyrrolidine (10 mL), and cuprous iodide (11 mg, 0.058 mmol, 0.25 eq) was added to the solution. 1-Iodo-1-propyne (191 mg, 1.15 mmol, 5 eq) was added dropwise to the mixture and stirred for 12 hours under nitrogen atmosphere at room temperature. After the reaction was completed, it was quenched with saturated aqueous ammonium chloride solution (20 mL), the aqueous phase was extracted with dichloromethane (3×20 mL), the organic solvent layer was collected, anhydrous sodium sulfate was added to the collected organic solvent layer for drying, and after drying, it was filtered, the filtrate was collected, and the filtrate was evaporated to dryness to obtain a crude product. The crude product was dissolved in dichloromethane, an equal amount of silica gel powder was added, the solvent was removed by evaporation under reduced pressure, and the product was added to a silica gel column for chromatography purification, using an eluent with a volume ratio of ethyl acetate:n-hexane = 1:50, and the eluent was collected. The eluent was evaporated under reduced pressure to remove the solvent to obtain a white solid product (yield: 38.8%), namely [1]benzothieno[3,2-b]benzothiophene conjugated small molecule photoresist, named C 5 BTBT-2yyC1.

[0143] This embodiment also provides a conjugated small molecule photoresist C prepared by the above method. 5 BTBT-2yyC1.

[0144] For the preparation of C 5 BTBT-2yyC1 was subjected to NMR analysis. 1 HNMR spectrum Fig.25 As shown, 13 C NMR spectrum Fig.26 As shown. 5 BTBT-2yyC1 was subjected to mass spectrometry analysis (mass spectrometry results are shown in Fig. 27 As shown), mass spectrometry analysis HRMS: [M] + C 34 H 32 S 2 Calculated 504.1945, found 504.4613. The above results confirm that the obtained product is the target product.

[0145] Example 10

[0146] A conjugated small molecule photoresist C 5The preparation method of BTBT-2yyC3 is basically the same as that of Example 9, except that the compound 1-iodo-1-propyne in Example 9 is replaced by an equal amount of the compound 1-iodo-1-pentyne (223 mg, 1.15 mmol, 5 eq); 5 The yield of BTBT-2yyC3 was 35.3%.

[0147] Preparation of conjugated small molecule photoresist C 5 The reaction formula of BTBT-2yyC3 is as follows:

[0148]

[0149] This embodiment also provides a conjugated small molecule photoresist C prepared by the above method. 5 BTBT-2yyC3.

[0150] For the preparation of C 5 BTBT-2yyC3 was subjected to NMR analysis. 1 HNMR spectrum Fig.28 As shown, 13 C NMR spectrum Fig.29 As shown. 5 BTBT-2yyC3 was subjected to mass spectrometry analysis (mass spectrometry results are shown in Fig.30 HRMS: [M]+C 38 H 40 S 2 Calculated 560.2571, found 560.5126. The above results confirm that the obtained product is the target product.

[0151] Embodiment 11

[0152] A conjugated small molecule photoresist C 6 The preparation method of BTBT-2yyC3 is basically the same as that of Example 9, except that: Compound C in Example 9 is 5 BTBT-2y replaced by C 6 BTBT-2y (100 mg, 0.22 mmol, 1 eq); 1-iodo-1-propyne was replaced by 1-iodo-1-pentyne (213 mg, 1.1 mmol 5 eq); C 6 The yield of BTBT-2yyC3 was 35.5%.

[0153] Preparation of conjugated small molecule photoresist C 6 The reaction formula of BTBT-2yyC3 is as follows:

[0154]

[0155] This embodiment also provides a conjugated small molecule photoresist C prepared by the above method. 6 BTBT-2yyC3.

[0156] For the preparation of C 6 BTBT-2yyC3 was subjected to NMR analysis. 1 HNMR spectrum Fig.31 As shown, 13 C NMR spectrum Fig.32 As shown. 6 BTBT-2yyC3 was subjected to mass spectrometry analysis (mass spectrometry results are shown in Fig.33 HRMS: [M]+C 40 H 44 S 2 Calculated 588.2884, found 588.5895. The above results confirm that the obtained product is the target product.

[0157] Example 12

[0158] A method for preparing an organic thin film transistor comprises the following steps:

[0159] S1: Modification of the dielectric layer of the silicon wafer

[0160] This step is carried out with reference to the previous patent CN116867340A of this research group. The specific process is: the purchased P-type doped silicon wafer with silicon dioxide as the gate dielectric layer is cut into a size of 15×15mm, and ultrasonicated in ultrapure water, acetone, isopropanol, and anhydrous ethanol for 20 minutes in turn, and then the silicon wafer is blown dry with nitrogen. A piranha solution is prepared by mixing 98% concentrated sulfuric acid and 30% hydrogen peroxide solution in a volume ratio of 7:3. The above-washed silicon wafer is immersed in the piranha solution and heated in a water bath at 80°C for 20 minutes. The silicon wafer is then washed with ultrapure water, and the surface is blown dry with nitrogen to complete the hydroxylation treatment of the dielectric layer. After that, the hydroxylated silicon wafer is immersed in a toluene solution of 7-octenyltrimethylsilane at 0.3v / v‰, and heated in an oil bath at 60°C for 12 hours. After the reaction is completed, the sample is washed with toluene and blown dry with nitrogen to complete the modification of the self-assembled monolayer of the dielectric layer. Take 10 mg of polystyrene thiol-capped (Sigma-Aldrich, molecular weight 10000) and dissolve it in 50 mL of toluene solution, and add 1 mg of benzoin dimethyl ether photoinitiator to the solution. Soak the silicon wafer modified in the previous step in the toluene solution with a concentration of 0.2 mg / mL of polystyrene thiol-capped. 2The samples were irradiated under a 365 nm ultraviolet lamp for 60 minutes to allow a click chemistry reaction between the terminal double bond of 7-octenyltrimethylsilane and the terminal thiol capped with polystyrene thiol. After the reaction, the samples were washed with a toluene solution to complete the polystyrene thiol capping of the self-assembled monolayer.

[0161] S2: Preparing an organic semiconductor thin film on the silicon wafer obtained in step S1

[0162] The conjugated small molecule photoresist C prepared in Example 7 5 BTBT-2y was prepared as a sample solution with a concentration of 2 mg / mL, and the solvent was a mixed solvent of toluene: chlorobenzene = 4:1 (v / v). The film was formed by scraping, with the angle between the scraper and the substrate surface being 45°, the scraper being 100 μm away from the substrate surface, 20 μL of the sample solution was added to the gap between the scraper and the silicon wafer, and the scraping speeds were 20, 40, 60, 80, 100, 120, 140, 160, 180, 200 μm / s, respectively, to form an organic semiconductor film.

[0163] S3: Preparation of organic thin film transistors

[0164] Paste the electrode mask and the organic semiconductor film obtained in step S1 and put them into the evaporator. Set the vacuum degree to 8×10 -4 Pa, the evaporation rate is Ag material is used to prepare a source electrode and a drain electrode with a thickness of 80 nm on the surface of an organic semiconductor film, thereby obtaining an organic thin film transistor with a bottom-gate top-contact structure.

[0165] This embodiment also provides an organic thin film transistor prepared by the above method.

[0166] Embodiment 13

[0167] A method for preparing an organic thin film transistor is basically the same as that of Example 12, except that the conjugated small molecule photoresist C in step S2 is 5 BTBT-2y was replaced by C prepared in Example 8 6 BTBT-2y.

[0168] This embodiment also provides an organic thin film transistor prepared by the above method.

[0169] Embodiment 14

[0170] A method for preparing an organic thin film transistor is basically the same as that of Example 12, except that the conjugated small molecule photoresist C in step S2 is 5 BTBT-2y was replaced by C prepared in Example 9 5 BTBT-2yyC1.

[0171] This embodiment also provides an organic thin film transistor prepared by the above method.

[0172] Embodiment 15

[0173] A method for preparing an organic thin film transistor is basically the same as that of Example 12, except that the conjugated small molecule photoresist C in step S2 is 5 BTBT-2y was replaced by C prepared in Example 10 5 BTBT-2yyC3.

[0174] This embodiment also provides an organic thin film transistor prepared by the above method.

[0175] Example 16

[0176] A method for preparing an organic thin film transistor is basically the same as that of Example 12, except that the conjugated small molecule photoresist C in step S2 is 5 BTBT-2y was replaced by C prepared in Example 11 6 BTBT-2yyC3.

[0177] This embodiment also provides an organic thin film transistor prepared by the above method.

[0178] Embodiment 17

[0179] A method for preparing a patterned organic thin film transistor comprises the following steps:

[0180] S1: Modification of the dielectric layer of the silicon wafer

[0181] The specific method is the same as Example 12

[0182] S2: Preparing a patterned organic semiconductor thin film on the silicon wafer obtained in step S1

[0183] Prepare 1 mL of a mixed solution of toluene:chlorobenzene = 4:1 (v / v), to which 2 mg (1 equivalent) of compound C prepared in Example 7 is added. 5BTBT-2y, take 9.4μL (0.4% eq) of toluene solution with a concentration of 1mg / mL photoinitiator into the mixed solution, and then add the crosslinker 1,3-propanedithiol (CAS: 109-80-8, hereinafter referred to as 2SH). The amount of crosslinker added is 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, and 20% equivalents, respectively. The mixed solution is fully shaken to obtain a sample solution. The film is formed by scraping, with the angle between the scraper and the substrate surface being 45°, and the scraper being 100μm away from the substrate surface. 20μL of the sample solution is added to the gap between the scraper and the silicon wafer, and the scraping speed is 140μm / s to form an organic semiconductor film. A mask is placed on the prepared organic semiconductor film, and the light power density used is 40mW / cm 2 A 365nm wavelength ultraviolet lamp was irradiated on the sample for 1 hour, so that the alkyne groups in the semiconductor molecules in the transparent part of the mask reacted with the thiol groups in the crosslinking agent to complete the polymerization between the molecules. The film was then rinsed with acetonitrile solution to wash away the molecules in the uncrosslinked part, and the photo-patterned organic semiconductor film on the silicon wafer was dried with nitrogen. The patterned organic semiconductor film image formed is as follows: Fig.34 shown.

[0184] S3: Fabrication of patterned organic thin film transistors

[0185] Paste the electrode mask and the patterned organic film and put them into the evaporator. Set the vacuum degree to 8×10 - 4 Pa, the evaporation rate is Ag material was used to prepare 80nm thick source and drain electrodes on the surface of the organic semiconductor film to obtain a patterned organic thin film transistor with a bottom gate and top contact structure.

[0186] This embodiment also provides a patterned organic thin film transistor prepared by the above method.

[0187] Embodiment 18

[0188] A method for preparing a patterned organic thin film transistor is basically the same as Example 17, except that the crosslinking agent in step S2 is replaced by tris[2-(3-mercaptopropionyloxy)ethyl isocyanurate] (CAS: 36196-44-8, hereinafter referred to as 3SH), and the addition amount of 3SH is 3%, 6%, 9%, 12%, and 15% equivalent, respectively. The patterned organic semiconductor thin film image formed in step S2 is as shown in FIG. Fig.35 shown.

[0189] This embodiment also provides a patterned organic thin film transistor prepared by the above method.

[0190] Embodiment 19

[0191] A method for preparing a patterned organic thin film transistor is basically the same as Example 17, except that the crosslinking agent in step S2 is replaced by pentaerythritol tetrakis(3-mercaptopropionic acid) ester (CAS: 7575-23-7, hereinafter referred to as 4SH), and the addition amount of 4SH is 2%, 4%, 6%, 8%, and 10% equivalents, respectively. The patterned organic semiconductor thin film image formed in step S2 is as shown in FIG. Fig.36 shown.

[0192] This embodiment also provides a patterned organic thin film transistor prepared by the above method.

[0193] Embodiment 20

[0194] A method for preparing a patterned organic thin film transistor comprises the following steps: substantially the same as in Example 17, except that the conjugated small molecule photoresist C in step S2 is 5 BTBT-2y was replaced by C prepared in Example 9 5 BTBT-2yyC1.

[0195] S1: Modification of the dielectric layer of the silicon wafer

[0196] The specific method is the same as Example 12

[0197] S2: Preparing a patterned organic semiconductor thin film on the silicon wafer obtained in step S1

[0198] Prepare a mixed solution of toluene:chlorobenzene = 4:1 (v / v) 1 mL, to which 2 mg of compound C prepared in Example 9 is added 5 BTBT-2yyC1, make a sample solution. Use scraping to form a film, the angle between the scraper and the substrate surface is 45°, the scraper is 100μm away from the substrate surface, add 20μL of sample solution into the gap between the scraper and the silicon wafer, and the scraping speed is 120μm / s to form an organic semiconductor film. Place a mask on the prepared organic semiconductor film, and use a light power density of 1mW / cm 2 A 254nm wavelength ultraviolet lamp was irradiated on the sample for 7 minutes to cause the diacetylene structure in the semiconductor molecules in the light-transmitting part of the mask to self-polymerize. The film was then rinsed with acetonitrile solution to wash away the molecules in the uncrosslinked part, and the photo-patterned organic semiconductor polymer film on the silicon wafer was dried with nitrogen. The patterned organic semiconductor film formed is as follows Fig.37 shown.

[0199] S3: Fabrication of patterned organic thin film transistors

[0200] The specific method is the same as Example 17

[0201] This embodiment also provides a patterned organic thin film transistor prepared by the above method.

[0202] Characterization and performance testing

[0203] Since compound C 6 BTBT-2y, C 6 BTBT-2yyC3、C 5 BTBT-2yyC3 and compound C 5 BTBT-2y, C 5 The structure and properties of BTBT-2yyC1 are similar, and the results are close. Therefore, taking the organic semiconductor film obtained in step S2 of Example 12 and Example 14 and the organic thin film transistor obtained in step S3 as examples, the following characterization and testing were performed.

[0204] 1. Characterization and testing of organic semiconductor films

[0205] 1. Polarized morphology characterization of organic semiconductor films

[0206] The polarization morphology of the organic semiconductor film obtained in step S2 of Example 12 and Example 14 at different scraping speeds was tested. The results are as follows: Fig.38 and 39 shown.

[0207] from Fig.38 and 39 It can be seen that with the increase of scraping speed, the crystal stripes change from disorder to order and then to disorder. The optimal scraping speed is about 120μm / s. At this speed, the crystals are arranged evenly, with fewer defects, and the quality of the organic semiconductor film is better.

[0208] 2. Atomic force microscopy testing of organic semiconductor films

[0209] The organic semiconductor films obtained in step S2 of Example 12 and Example 14 were tested by atomic force microscopy. The results are as follows: Fig.40 and 41 shown.

[0210] from Fig.40 and Fig.41 It can be seen that the scraping speed has a significant effect on the surface morphology and thickness of the film. With the increase of the scraping speed, the film thickness gradually decreases, and the film thickness no longer decreases at a speed of 120 μm / s. Further increasing the speed makes the film surface rough and uneven.

[0211] 3. X-ray diffraction test of organic semiconductor films

[0212] The organic semiconductor films obtained in step S2 of Example 12 and Example 14 were subjected to X-ray diffraction test. The results are as follows: Fig.42shown.

[0213] Fig.42 The results show that the films show obvious diffraction peaks at different scraping speeds. 5 The three diffraction peaks of BTBT-2y film are located at 2θ=3.53°, 7.09° and 10.62°, and the corresponding interplanar spacings are and C 5 The three diffraction peaks of BTBT-2yyC1 film are located at 2θ=3.23°, 6.52° and 9.78°, and the corresponding interplanar spacings are and This indicates that the molecules are well stacked to form an ordered crystalline film.

[0214] 2. Performance test of organic thin film transistors

[0215] The performance of the organic thin film transistors prepared in Example 12 and Example 14 was tested using a semiconductor testing platform.

[0216] Fig.43 The transfer and output characteristic curves of the organic thin film transistor prepared in Example 12 (corresponding to a scraping speed of 140 μm / s) and the carrier mobility variation diagram at different scraping speeds are shown in FIG. Fig.43 The results show that the carrier mobility of the organic thin film transistor is 2.17 cm 2 V -1 s -1 , and good charge transfer performance can only be obtained when the scraping speed is appropriate.

[0217] Fig.44 The transfer and output characteristic curves of the organic thin film transistor prepared in Example 14 (corresponding to a scraping speed of 120 μm / s) and the carrier mobility variation diagram at different scraping speeds are shown in FIG. Fig.44 The results show that the carrier mobility of the organic thin film transistor is 0.46 cm 2 V -1 s -1 , and good charge transfer performance can only be obtained when the scraping speed is appropriate.

[0218] 3. Performance test of patterned organic thin film transistors

[0219] The performance of the patterned organic thin film transistors prepared in Examples 17-20 was tested using a semiconductor testing platform.

[0220] Fig.45 The carrier mobility results of the patterned organic thin film transistors prepared in Examples 17-19. Fig.45The results show that: 2SH has the maximum carrier mobility when the content is 14% (corresponding to Example 17), 3SH has the maximum carrier mobility when the content is 6% (corresponding to Example 18), and 4SH has the maximum carrier mobility when the content is 4% (corresponding to Example 19). At the same time, the maximum value of the carrier mobility of the device containing 3SH is higher than that of 2SH and 4SH.

[0221] Fig.46 The figure is a statistical histogram of the carrier mobility exhibited by the 36 patterned devices prepared in Example 20. It can be seen from the figure that the carrier mobility is mainly concentrated in the range of 0.05-0.15 cm 2 V -1 s -1 between.

[0222] In summary, the [1]benzothieno[3,2-b]benzothiophene-based conjugated small molecule semiconductor photoresist prepared by the present invention has great application potential in the preparation of miniaturized and integrable electronic devices based on thin film transistors in the future.

[0223] The above embodiments are intended to illustrate the essential content of the present invention, but are not intended to limit the protection scope of the present invention. Those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and protection scope of the technical solution of the present invention.

Claims

1. A conjugated small molecule photoresist, characterized in that: The structural formula is shown in Formula 1 or Formula 2: Among them, m=4 or 5; n=0 or 2.

2. The method for preparing the conjugated small molecule photoresist according to claim 1, characterized in that: The following steps are involved: (1) Preparation of Compound C m BTBT-2Si: Add trimethylsilyl acetylene to solvent A, cool to -78-80°C, add n-butyl lithium, stir for 1-1.5h, then add hexamethylphosphoramide and compound C in sequence m BTBT-2Br, heated to room temperature and stirred for 16-18h, then added with ammonium chloride solution to quench the reaction, and compound C was obtained after separation and purification. m BTBT-2Si; The compound C m BTBT-2Br and compound C m The structural formula of BTBT-2Si is as follows: (2) Preparing a conjugated small molecule photoresist having a structural formula as shown in Formula 1: Compound C m BTBT-2Si is added to solvent B, and potassium carbonate is added, and the mixture is stirred and reacted at 40-50° C. After the reaction is completed, a conjugated small molecule photoresist having a structural formula as shown in Formula 1 is obtained by separation and purification, wherein m=4 or 5; (3) Preparing a conjugated small molecule photoresist having a structural formula as shown in Formula 2: A conjugated small molecule photoresist with a structural formula as shown in Formula 1 is added to a solvent C, and then cuprous iodide and compound A are added, and the reaction is stirred for 12 to 14 hours under an inert gas atmosphere, and an aqueous solution of ammonium chloride is added to quench the reaction, and a conjugated small molecule photoresist with a structural formula as shown in Formula 2 is obtained after separation and purification, wherein m=4 or 5, and n=0 or 2; The structural formula of compound A is as follows: Where n=0 or 2.

3. The method for preparing the conjugated small molecule photoresist according to claim 2, characterized in that: Compound C in step (2) m The molar ratio of BTBT-2Si to potassium carbonate is 1:(5-5.5); the molar ratio of the conjugated small molecule photoresist having the structural formula shown in Formula 1 in step (3) to cuprous iodide and compound A is 1:(0.25-0.3):(5-5.5).

4. The method for preparing the conjugated small molecule photoresist according to claim 2, characterized in that: Compound C in step (1) m The molar ratio of BTBT-2Br to trimethylsilylacetylene, n-butyl lithium and hexamethylphosphoramide is 1:(5-5.5):(5-5.5):(5-5.5).

5. The method for preparing the conjugated small molecule photoresist according to claim 4, characterized in that: The compound C m The preparation method of BTBT-2Br is as follows: under an inert gas atmosphere, compound C m BTBT-2acyl is added to solvent D, and sodium borohydride and aluminum chloride are added after cooling to 0°C, and then the reaction solution is heated to 90-95°C for 12-14 hours. After the reaction is completed, the compound C is obtained by separation and purification. m BTBT-2Br; Wherein, the compound C m The structural formula of BTBT-2acyl is as follows:

6. The method for preparing the conjugated small molecule photoresist according to claim 5, characterized in that: The compound C m The molar ratio of BTBT-2acyl, sodium borohydride and aluminum chloride is 1:(10-11):(5-5.5).

7. The method for preparing the conjugated small molecule photoresist according to claim 6, characterized in that: The compound C m The preparation method of BTBT-2acyl is as follows: adding compound BTBT to solvent E, cooling to -10 to -15°C, adding aluminum chloride, further cooling to -80 to -85°C, adding compound B, keeping the temperature to react overnight, and after the reaction is completed, separating and purifying to obtain compound C m BTBT-2acyl; The structural formulas of the compound BTBT and compound B are as follows:

8. The method for preparing the conjugated small molecule photoresist according to claim 7, characterized in that: The molar ratio of the compound BTBT, aluminum chloride and compound B is 1:(5-5.5):(5-5.5).

9. Use of the conjugated small molecule photoresist according to claim 1 in the preparation of an organic thin film transistor.

10. The use according to claim 9, characterized in that: The organic thin film transistor comprises, from bottom to top, a substrate, a gate electrode, a dielectric layer, an organic semiconductor film and a source-drain electrode layer, and the organic semiconductor film is prepared by any one of the conjugated small molecule photoresists described in claim 1.

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