High-resolution block copolymer capable of being quickly self-assembled at low temperature, preparation method of block copolymer and application of block copolymer in organic thin film transistor

Abstract

The invention belongs to the technical field of polymer materials, and provides a high-resolution block copolymer capable of being quickly self-assembled at a low temperature, a preparation method of the high-resolution block copolymer and application of the high-resolution block copolymer in an organic thin film transistor. One block structure of the high-resolution block copolymer capable of being rapidly self-assembled at low temperature comprises at least one of formulas (A)-(D), the phase separation size is small, the resolution is high, the resolution can reach sub-5nm-20nm, an electret can be completely wrapped in a certain block and is isolated from a semiconductor layer, low-temperature rapid self-assembly can be achieved, and the high-resolution block copolymer capable of being rapidly self-assembled at low temperature can be used for preparing the high-resolution block copolymer. Therefore, the influence of high temperature on the performance of the device is overcome. Furthermore, an organic thin-film transistor is prepared from the block copolymer capable of being quickly self-assembled at low temperature and high in resolution, the storage window of the organic thin-film transistor can reach 43-46V, the current switch ratio is about 104-106, and the organic thin-film transistor can be used as an organic thin-film transistor memory with excellent performance.

Description

Technical Field

[0001] The present invention relates to the technical fields of block copolymers and lithography technology. More specifically, it relates to a block copolymer that can self-assemble at low temperature quickly and with high resolution, and its preparation method and application in organic thin-film transistors. Background Art

[0002] With the rapid development of the Internet of Things and artificial intelligence, the urgent need for information storage in daily life is increasing day by day. However, there is a huge gap between the currently created data volume and the storage capacity, which has led to the "Memory wall" bottleneck in the development of digital technology. To address this issue, high-performance storage devices based on new architectures and functions are being vigorously developed, such as resistive random access memory, non-volatile transistor memory, and phase change memory, etc. Among them, transistor memory has been proven to have excellent multi-level data storage performance. Generally, for a high-performance transistor memory, it is not only required to have a large memory window and a high on / off current ratio (I ON / OFF ), but also required to have good stability and excellent durability.

[0003] As a polymer with adjustable chemical structure, block copolymers have received extensive attention in the field of transistor memory. The self-assembly of block copolymers can not only pattern the functional layer of the device, but also this material itself can be used as the functional layer of the storage device, which further expands the application of block copolymers in the field of storage devices. For example, insulating block copolymers can be used as dielectric materials or lithography templates to prepare field-effect transistors, while fully conjugated block copolymers can be used as channel materials to prepare organic field-effect transistors. In addition, for some block copolymers with tensile resistance, they can also be used to prepare stretchable transistors or flexible transistor devices.

[0004] In recent years, a new type of transistor memory has emerged, namely optoelectronic transistor memory, which is prepared from materials with photosensitive functions. Its operating mechanism can be triggered not only by the applied voltage, but also by light of a specific wavelength. Therefore, during the programming or erasing process, the device can be partially or completely operated by light. Thanks to the photosensitive material, optoelectronic transistor memory can overcome the problems of high energy consumption and limited charge transfer speed of conventional electrically controlled transistor memory. However, it has problems with poor memory window and current on / off ratio.

[0005] Therefore, it is urgent to develop an organic thin-film transistor with a large memory window and a high on / off current ratio. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. For this purpose, the present invention provides a block copolymer that can self-assemble at low temperature and rapidly with high resolution, a preparation method thereof, and an application thereof in an organic thin-film transistor. The block copolymer provided by the present invention has a low surface energy, can achieve excellent phase separation and rapid self-assembly under low annealing temperature (such as 80 °C) and short annealing time conditions (such as 5 min), obtain nanostructures with small size and high resolution, and can reach a resolution of sub-5 nm. Further, an organic thin-film transistor is prepared by using the block copolymer that can self-assemble at low temperature and rapidly with high resolution provided by the present invention, and its memory window can reach 43 - 46 V, and the current on / off ratio (I ON / OFF ) can be as high as 10 4 -10 6 , and it can be used as an organic thin-film transistor memory with excellent performance.

[0007] The first aspect of the present invention provides a block copolymer containing a block copolymer that can self-assemble at low temperature and rapidly with high resolution.

[0008] Specifically, a block copolymer that can self-assemble at low temperature and rapidly with high resolution includes at least one block selected from the following formula (A) - formula (D):

[0009]

[0010] wherein x, y, z, and w are independently selected from positive integers of 5 - 100;

[0011] R f1 is one of -H, -CH3, -CF3, and halogen;

[0012] R f2 is a halogenated alkyl group with 1 - 20 carbon atoms;

[0013] R f3 is one of -H, -CH3, -CF3, and halogen;

[0014] R f4 is a halogenated alkyl group with 1 - 20 carbon atoms or halogen; R f4 substitutes the para-position of the substituted benzene ring, the meta-position of the substituted benzene ring, the ortho-position of the substituted benzene ring, or simultaneously substitutes two or more positions on the benzene ring;

[0015] R f5 -R f8 are independently selected from halogenated alkyl groups with 1 - 20 carbon atoms;

[0016] R f9 -R f12 are independently selected from halogenated alkyl groups with 1 - 20 carbon atoms.

[0017] The block copolymer provided by the present invention is capable of low-temperature rapid self-assembly and has high resolution. Since the surface energy of the halogen-containing block therein is very low, this block copolymer easily repels small molecules into other halogen-free blocks, which helps to completely encapsulate the electret in a certain block and isolate it from the semiconductor layer. In addition, the phase separation size of the block copolymer of the present invention is small and the resolution is high, and a resolution of sub-5 nm can be achieved, thereby increasing the density of the electret per unit area. Further, using such a block copolymer capable of low-temperature rapid self-assembly and having high resolution to prepare an organic thin-film transistor is conducive to obtaining a large storage window and a high current on-off ratio.

[0018] Preferably, R f2 is one of a hydroxyl group, a carboxyl group, a C1-C6 straight-chain or branched alkyl group that is unsubstituted or substituted by at least one of a hydroxyl group, an alkoxy group, a silyl group, and a halogen, and a C6-C10 aryl group that is unsubstituted or substituted by a hydroxyl group or a halogen.

[0019] Preferably, the halogen is at least one of fluorine, chlorine, bromine, and iodine.

[0020] More preferably, the halogen is fluorine.

[0021] The second aspect of the present invention provides a method for preparing a block copolymer capable of low-temperature rapid self-assembly and having high resolution.

[0022] A method for preparing a block copolymer capable of low-temperature rapid self-assembly and having high resolution includes the following steps:

[0023] Mix a halogen-containing polymer and a monomer, and prepare the block copolymer through a polymerization reaction;

[0024] Or;

[0025] Mix a halogen-containing monomer and a polymer, and prepare the block copolymer through a polymerization reaction.

[0026] Preferably, the halogen-containing polymer is poly(1H,1H-perfluorooctyl methacrylate), the monomer is 4-acetoxystyrene, and the block copolymer is poly(p-hydroxystyrene)-b-poly(1H,1H-perfluorooctyl methacrylate); or, the halogen-containing monomer is 1H,1H-perfluorobutyl methacrylate, the polymer is poly(2-vinylpyridine), and the block copolymer is poly(2-vinylpyridine)-b-poly(1H,1H-perfluorobutyl methacrylate).

[0027] Wherein "b" represents a block copolymer.

[0028] Preferably, the initiator for the polymerization reaction is azobisisobutyronitrile.

[0029] Preferably, the temperature of the polymerization reaction is 60-70 °C, and / or the time of the polymerization reaction is 10-30 h.

[0030] The third aspect of the present invention provides an application of a block copolymer that can self-assemble at low temperature quickly and with high resolution.

[0031] An application of a block copolymer that can self-assemble at low temperature quickly and with high resolution in the preparation of organic electronic devices.

[0032] Preferably, the organic electronic device is an organic thin film transistor.

[0033] The fourth aspect of the present invention provides an organic thin film transistor.

[0034] An organic thin film transistor, which includes a substrate, a composite film, an organic semiconductor layer, and a metal electrode stacked in sequence. The preparation raw materials of the composite film include the block copolymer and a functional material, and the functional material is a conductive and / or photosensitive material.

[0035] The block copolymer provided by the present invention has a high χ value (Flory-Huggins constant) (0.347-0.448), can self-assemble quickly at low temperature, and has high resolution. Further, using the block copolymer provided by the present invention as a carrier, doping a functional material in the block copolymer, and they are enriched in one of the smallest units (domains) and form new nanostructures (donor-acceptor) with certain optoelectronic properties through hydrogen bonds, ionic bonds, coordination bonds, etc., ultimately improving the on-off ratio and storage window of the device. The present invention uses the composite film as the charge trapping layer of the organic thin film transistor. Among them, the block copolymer can not only achieve annealing self-assembly at a lower temperature to form an ordered nanostructure beneficial to charge stability, but also isolate the conductive and / or photosensitive functional material as an electret from the semiconductor layer, thereby avoiding potential charge loss and increasing the charge storage capacity of the device. In addition, by regulating the composition, structure, and orientation of the block copolymer, the device performance can also be regulated.

[0036] Preferably, the composite film has nanostructures, and the size of the nanostructures is 5-20 nm.

[0037] Preferably, the substrate is a highly doped silicon wafer containing a SiO2 layer.

[0038] Preferably, the thickness of the SiO2 layer is 100-300 nm.

[0039] Preferably, the molar ratio of the block copolymer to the functional material is (1-10):1.

[0040] Further preferably, the molar ratio of the block copolymer to the functional material is (2 - 5):1.

[0041] Preferably, the functional material is an inorganic functional material and / or an organic functional material.

[0042] Preferably, the inorganic functional material is at least one of perovskite-based photosensitive functional materials (such as MAPbBr3), metal nanostructure-based photosensitive functional materials, C60, carbon nanotubes, and quantum dot materials.

[0043] Preferably, the organic functional material is at least one of pyrene-based photosensitive compounds (such as 1-aminopyrene), thiophene-based photosensitive compounds, ferrocene-based photosensitive compounds, and donor-acceptor polymers.

[0044] Preferably, the material of the organic semiconductor layer is at least one of pentacene, 2,7-dioctyl[1]benzothieno[3,2-b]benzothiophene (C8-BTBT), poly(3-hexylthiophene) (P3HT), and 6,13-bis(triisopropylsilylethynyl)pentacene.

[0045] Preferably, the thickness of the composite film is 45 - 55 nm, and / or the thickness of the organic semiconductor layer is 30 - 100 nm, and / or the thickness of the metal electrode is 45 - 55 nm.

[0046] Preferably, the metal electrode is an Au electrode.

[0047] The fifth aspect of the present invention provides a method for preparing an organic thin film transistor.

[0048] A method for preparing an organic thin film transistor, comprising the following steps:

[0049] (1) Take the solution of the block copolymer, mix it with the functional material to obtain a mixed solution;

[0050] (2) Coat the mixed solution on the surface of the substrate, evaporate the solvent, and then perform thermal annealing self-assembly to obtain a composite film;

[0051] (3) Grow an organic semiconductor layer on the surface of the composite film;

[0052] (4) Grow a metal electrode on the surface of the organic semiconductor layer to obtain the organic thin film transistor.

[0053] The present invention bypasses the traditional lithography process and directly forms a composite film containing nanostructures (minimum units, domains) with sizes of 5-20 nm through the self-assembly of the provided block copolymer. These nanostructures can be at least one of lamellar, columnar, and spherical (schematic diagrams of lamellar, columnar, and spherical nanostructures are respectively as shown in Figure 6 A - C).

[0054] Preferably, in step (1), the block copolymer is dissolved in an organic solvent to prepare a solution of the block copolymer.

[0055] Preferably, the organic solvent is N,N - dimethylformamide (DMF).

[0056] Preferably, in step (1), after mixing, it is filtered through a filter head with a pore size of 0.20 - 0.25 μm to obtain a mixed solution.

[0057] Preferably, in step (2), before use, the substrate is ultrasonically cleaned with acetone, isopropyl alcohol, and deionized water for 10 - 30 min in sequence, and then cleaned with O2 plasma for 10 - 30 min.

[0058] Preferably, in step (2), the coating is spin coating.

[0059] Preferably, in step (2), the temperature of the thermal annealing self - assembly is 80 - 120 °C, and / or the time of the thermal annealing self - assembly is 1 - 5 min.

[0060] The preparation method of the organic thin - film transistor provided by the present invention can be compatible with the existing process. The existing lithography process generally bakes at 100 - 130 °C for no more than 5 min, while the present invention combines spin coating and low - temperature rapid thermal annealing self - assembly to achieve the compatibility of the two.

[0061] Preferably, in step (3), using a hard mask, an organic semiconductor layer is grown on the surface of the composite film by thermal evaporation.

[0062] Preferably, in step (4), using a hard mask, a metal electrode is grown on the surface of the organic semiconductor layer by magnetron sputtering.

[0063] The sixth aspect of the present invention provides an application of an organic thin - film transistor.

[0064] An application of an organic thin - film transistor in the preparation of memory, sensors, and display devices.

[0065] Preferably, the memory is an organic thin - film transistor memory.

[0066] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0067] The block copolymer provided by the present invention can be self-assembled rapidly at low temperature and has high resolution. It includes at least one block in formulas (A)-(D). Since it has halogen groups, this block easily repels small molecules into another block without halogen groups, which helps to completely wrap the electret in a certain block and isolate it from the semiconductor layer. Moreover, the phase separation size of the block copolymer of the present invention is small and the resolution is high, reaching a resolution of sub-5 nm, and thus the density of the electret per unit area can be increased. The high-resolution block copolymer of the present invention is compatible with the process at a relatively low annealing temperature (80-120 °C), avoiding the use of solvent annealing methods; functional small molecules have poor thermal stability, so thermal annealing at >120 °C is often unfavorable to small molecules, which in turn affects the performance of the device. However, the block copolymer of the present invention can achieve low-temperature rapid self-assembly at 120 °C and below, without high-temperature treatment, avoiding the adverse effects of high temperature on functional small molecules, thereby overcoming the influence of high-temperature processes on device performance. Further, an organic thin-film transistor is prepared by using the block copolymer provided by the present invention that can be self-assembled rapidly at low temperature and has high resolution. Its memory window can reach 43-46 V, and the current on / off ratio (I ON / OFF ) can reach 10 4 -10 6 , and it can be used as an organic thin-film transistor memory with excellent performance. Description of the Drawings

[0068] Figure 1 FIG. 13 is a process flow chart of preparing an organic thin-film transistor memory based on the block copolymer and functional materials in Application Example 1;

[0069] Figure 2 FIG. 17 is a scanning electron microscope image (SEM) of the block copolymer prepared in Example 1;

[0070] Figure 3 FIG. 21 is a transfer curve of the organic thin-film transistor memory based on P4HS-b-PPDFMA@1-aminopyrene prepared in Application Example 1;

[0071] Figure 4 FIG. 25 is a transfer curve of the organic thin-film transistor memory based on P2VP-b-PHFBMA@MAPbBr3 prepared in Application Example 2;

[0072] Figure 5 FIG. 29 is a retention characteristic diagram of the organic thin-film transistor memory based on P2VP-b-PHFBMA@MAPbBr3 prepared in Application Example 2;

[0073] Figure 6 FIG. 33 is a schematic diagram of different-shaped nanostructures in the composite film;

[0074] Figure 7 Schematic structural diagram of the organic thin-film transistor prepared in Application Example 1 of the present invention;

[0075] Figure 8 1H nuclear magnetic resonance spectrum ( 1 1H NMR) of the block copolymer P4AS-b-PPDFMA prepared in Example 1 of the present invention;

[0076] Figure 9 1H nuclear magnetic resonance spectrum ( 1 1H NMR) of the block copolymer P4HS-b-PPDFMA prepared in Example 1 of the present invention;

[0077] Figure 10 Transfer curve diagram of the organic thin-film transistor memory based on PS@1-aminopyrene prepared in Comparative Application Example 1. Detailed implementation manners

[0078] In order to make those skilled in the art more clearly understand the technical solutions of the present invention, the following examples are listed for illustration. It should be noted that the following examples do not limit the scope of protection required by the present invention.

[0079] The raw materials, reagents or devices used in the following examples can be obtained from conventional commercial channels or can be obtained by existing known methods without special instructions.

[0080] Example 1

[0081] A preparation method of a halogen-containing block copolymer (poly(p-hydroxystyrene)-b-poly(1H,1H-perfluorooctyl methacrylate), abbreviated as P4HS-b-PPDFMA) includes the following steps:

[0082] In a dry 25 mL polymerization tube, 0.5 mg of azobisisobutyronitrile (AIBN, 0.003 mmol), 100 mg of poly(1H,1H-perfluorooctyl methacrylate) (abbreviated as PPDFMA, 0.027 mmol when taking PPDFMA8), and 120 mg of 4-acetoxystyrene monomer (abbreviated as 4AS, 0.74 mmol) dissolved in 1.5 mL of hexafluoroisopropanol (HFIP) were added. After sufficient stirring with a magnetic stirrer, the system was subjected to three freeze-thaw cycles, and finally the system in the polymerization tube was placed under argon protection. After the system temperature returned to room temperature, the polymerization tube was placed in an oil bath preheated to 65 °C, stirred thoroughly under nitrogen protection, and the tube was sealed and reacted for 20 h and then taken out. Then the polymerization tube was quickly placed in liquid nitrogen to quench the reaction. After the reaction tube and the system inside returned to room temperature, 1.5 mL of HFIP was added to dilute the system in the polymerization tube, and then the solution in the polymerization tube was slowly dropped into 100 mL of methanol under stirring for precipitation. After centrifuging and separating the precipitate, the obtained solid was redissolved with HFIP and reprecipitated in methanol. After repeating three times, the obtained product was dried under vacuum at 40 °C for 24 h to obtain P4AS-b-PPDFMA solid.

[0083] 100 mg of P4AS-b-PPDFMA was added to a 10 mL test tube and dissolved in 100 μL of tetrahydrofuran by magnetic stirring. While maintaining the stirring, the bottom of the test tube was immersed in ice water, and 50 μL of 10 mol / L HCl solution was slowly added dropwise to the system in the test tube. After the addition was completed, the ice bath was removed, and the test tube was stirred at room temperature for 16 h. Then the solution in the test tube was dropped into 50 mL of n-hexane under ultrasonic for precipitation. After centrifuging and separating, it was redissolved with tetrahydrofuran and reprecipitated in n-hexane under ultrasonic. After repeating three times, the obtained product was dried under vacuum at 40 °C for 24 h to obtain P4HS-b-PPDFMA solid (where the degree of polymerization m is 15 - 20 and n is 5 - 10). Figure 8 For the synthesized P4AS-b-PPDFMA 1 1H NMR spectrum, δ (ppm): 7.17 - 6.21 (4H, Ar-H), 4.37 (2H, OCH2C7F 15 ) Figure 9 For the synthesized P4HS-b-PPDFMA 1 1H NMR spectrum, in which the signal peak of the methyl group at the acetoxy end (δ ~ 2.22 ppm) completely disappeared, and a new characteristic peak of the hydroxyl group (δ ~ 7.91 ppm) appeared, indicating complete hydrolysis. The results showed that P4HS-b-PPDFMA was successfully synthesized in Example 1, and its structure is shown in formula (E). Among them, Figure 8 and Figure 9 in Chemical Shift (ppm) is the chemical shift.

[0084] The above reaction equation is as follows:

[0085]

[0086]

[0087] Among them, Hydrolysis with acid means acid hydrolysis, and Excess amount of 10M HCl means excessive 10 mol / L HCl.

[0088] Example 2

[0089] A preparation method of a halogen-containing block copolymer (poly(2-vinylpyridine)-b-poly(1H,1H-perfluorobutyl methacrylate), abbreviated as P2VP-b-PHFBMA) includes the following steps:

[0090] First, pre-dry the polymerization reaction flask, and add 35 mL of tetrahydrofuran and 4 mL of dibutylmagnesium solution under the protection of high-purity argon. After the mixed system is stirred in an oil bath at 35 °C for 30 min, it is flash distilled into a reaction flask containing 0.13 g of dry anhydrous LiCl powder (2.6 mmol of anhydrous lithium chloride, which is 5 equivalents of the initiator), and 2 mL of 2-vinylpyridine monomer flash distilled with triisobutylaluminum is added. The reaction flask is cooled to -80 °C in a mixed solution of liquid nitrogen and ethanol. After 10 min, 0.5 mL of sec-butyllithium (1.3 mol / L n-hexane solution) is added to initiate polymerization to obtain poly(2-vinylpyridine) (P2VP), and the solution turns dark orange-red. When the polymerization reaction of the P2VP segment lasts for 30 min, 2.0 mL of HFBMA monomer (1H,1H-perfluorobutyl methacrylate) is slowly added dropwise (treated with AlBu3 and then flash distilled). As the second-stage polymerization reaction occurs, the color of the system slowly fades to colorless, and the reaction system continues to polymerize at low temperature for 30 min. Finally, it is quenched with 0.5 mL of high-purity degassed methanol. After the system returns to room temperature, it is precipitated twice in a mixed solution of methanol and water (volume ratio 1:1), and a white solid powder P2VP-b-PHFBMA polymer (the degree of polymerization m is 20 - 25, and n is 30 - 35) is obtained after vacuum drying.

[0091] The above reaction equation is as follows:

[0092]

[0093] Application Example 1

[0094] A preparation method of an organic thin-film transistor includes the following steps:

[0095] (1) Weigh 50 mg of P4HS-b-PPDFMA prepared in Example 1 into a round-bottom flask, measure 5 mL of DMF into the round-bottom flask, and stir until completely dissolved to obtain a solution of the block copolymer. Weigh 1-aminopyrene into the round-bottom flask according to a molar ratio of P4HS-b-PPDFMA:1-aminopyrene of 5:1, and stir vigorously at 50 °C for 24 h (the amino group in 1-aminopyrene is bonded to the hydroxyl group in P4HS-b-PPDFMA through a hydrogen bond). Filter the mixed solution through a PTFE filter head with a pore size of 0.22 μm for later use.

[0096] (2) Ultrasonically clean a highly doped silicon wafer (substrate) with a 300-nm-thick SiO2 layer in acetone, isopropyl alcohol, and deionized water for 20 min each in turn, and then clean it with O2 plasma for 20 min to obtain a pretreated substrate.

[0097] (3) Spin-coat the mixed solution in (1) on the surface of the pretreated substrate at 2000 rpm for 60 s to obtain a P4HS-b-PHFBMA@1-aminopyrene composite film with a thickness of about 50 nm. Then place it in an N2 environment and heat it at 40 °C for 3 h until the solvent evaporates completely, and then perform self-assembly by thermal annealing at 80 °C for 5 min.

[0098] (4) Use a hard mask and adopt a thermal evaporation technique to grow about 30 nm thick C8-BTBT on the above composite film layer.

[0099] (5) Use a hard mask and adopt a magnetron sputtering technique to grow an Au electrode with a thickness of about 50 nm on the above organic semiconductor layer.

[0100] The preparation process of Application Example 1 is as Figure 1 shown, where Spin-coating in the figure is spin coating, ChargeableComposite Layer is the rechargeable composite layer (i.e., the composite film), Thermal Evaporation is thermal evaporation, OrganicSemiconductor is the organic semiconductor layer, and Magnetron Sputtering is magnetron sputtering. The structure of the organic thin-film transistor prepared in Application Example 1 is as Figure 7 shown, which includes a substrate, a composite film, an organic semiconductor layer, and a metal electrode stacked from top to bottom in sequence.

[0101] Application Example 2

[0102] A method for preparing an organic thin-film transistor, comprising the following steps:

[0103] (1) Weigh 50 mg of P2VP-b-PHFBMA prepared in Example 2 into a round-bottom flask, measure 5 mL of DMF into the round-bottom flask, and stir until completely dissolved. Measure the precursor solution of MAPbBr3 into the round-bottom flask according to the molar ratio of P2VP-b-PHFBMA:MAPbBr3 = 2:1, and stir vigorously at room temperature for 10 h (the lead ions in MAPbBr3 are bonded to the pyridine in P2VP-b-PPDFMA through Lewis acid-base interaction). Filter the mixed solution with a PTFE filter head with a pore size of 0.23 μm for later use;

[0104] (2) Ultrasonically clean the highly doped silicon wafer with a 300-nm-thick SiO2 layer successively with acetone, isopropyl alcohol, and deionized water for 20 min each, and then clean it with O2 plasma for 20 min for later use;

[0105] (3) Spin-coat the mixed solution in (1) at 2000 rpm for 60 s to obtain a P2VP-b-PHFBMA@MAPbBr3 composite film with a thickness of about 50 nm. Then place it in an N2 environment and heat it at 40 °C for 3 h until the solvent evaporates completely, and then perform self-assembly by thermal annealing at 120 °C for 5 min;

[0106] (4) Using a hard mask, grow pentacene with a thickness of 30 nm on the above composite film layer by thermal evaporation technology;

[0107] (5) Using a hard mask, grow an Au electrode with a thickness of about 50 nm on the above organic semiconductor layer by magnetron sputtering technology to prepare an organic thin-film transistor.

[0108] Comparative Application Example 1

[0109] A method for preparing an organic thin-film transistor includes the following steps:

[0110] (1) Weigh 50 mg of polystyrene (PS) into a round-bottom flask, measure 5 mL of propylene glycol monomethyl ether acetate (PGMEA) into the round-bottom flask, and stir until completely dissolved. Weigh 1-aminopyrene into the round-bottom flask according to the molar ratio of PS:1-aminopyrene = 5:1, stir well for 24 h, filter the mixed solution with a PTFE filter head with a pore size of 0.22 μm for later use to obtain a mixed solution;

[0111] (2) Ultrasonically clean the highly doped silicon wafer (substrate) with a 300-nm-thick SiO2 layer successively with acetone, isopropyl alcohol, and deionized water for 20 min each, and then clean it with O2 plasma for 20 min to obtain a pretreated substrate;

[0112] (3) Spin coat the mixed solution in (1) on the surface of the pretreated substrate at 2000 rpm for 60 s to obtain a PS@1-aminopyrene composite film with a thickness of about 50 nm, and then place it in an N2 environment and heat it at 40 °C for 3 h until the solvent evaporates completely;

[0113] (4) Using a hard mask, grow about 30 nm thick C8-BTBT (2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene) on the above composite film by thermal evaporation technology;

[0114] (5) Using a hard mask, grow an Au electrode with a thickness of about 50 nm on the above organic semiconductor layer C8-BTBT by magnetron sputtering technology to prepare an organic thin film transistor.

[0115] Product effect test

[0116] Figure 2 Figure 13 is the SEM image of the halogen-containing block copolymer prepared in Example 1. It can be seen from the figure that the phase separation size of the halogen-containing block copolymer is small and the resolution is high, reaching an extremely high resolution of sub-5 nm, which can further increase the density of electrets per unit area.

[0117] According to the small-angle X-ray scattering (SAXS) absolute intensity random phase approximation (RPA), the χ value of PPDFMA-b-P4HS prepared in Example 1 at 200 °C is 0.448, and the χ value of PHFBMA-b-P2VP prepared in Example 2 at 200 °C is 0.347.

[0118] Use a Keithley 4200-SCS semiconductor performance comprehensive analyzer to test the electrical performance of the organic thin film transistors prepared in Application Example 1 and Application Example 2, and the results are respectively as Figure 3 and Figure 4 shown. Figure 3 Figure 25 is the transfer curve of the organic thin film transistor in Application Example 1, and its memory window can reach 46 V, and the current on-off ratio (I ON / OFF ) is about 10 5 . Figure 4 Figure 31 is the transfer curve of the device in Application Example 2, and its memory window can reach 43 V, and the current on-off ratio (I ON / OFF ) is about 10 4 . By regulating the structure and orientation of the halogen-containing block copolymer and the molar ratio of the fluorine-containing block copolymer to the photosensitive functional material, it is expected to prepare a transistor memory with better performance. Figure 5 Figure 37 is the retention characteristic diagram of the device in Application Example 2, where OnState is the on state (V GS= 80V, 1s), the OFF State is the disconnected state (V GS = -80V, 1s), when the device is at V DS = -5V, V GS = 0V condition, I DS remains relatively stable within 10 4 s and the switching ratio is maintained at 10 3 . Figure 10 is the transfer curve of the device prepared for Comparative Application Example 1, with a storage window of 42V and a current switching ratio (I ON / OFF ) of approximately 10 3 . Compared with Application Example 1, the storage window of the device has decreased and the switching ratio has decreased significantly.

Claims

1. A block copolymer, characterized in that, Comprising at least one block selected from the following formulas (A) - (D): wherein x, y, z, and w are each independently selected from positive integers of 5 - 100; R f1 is one of -H, -CH3, -CF3, and halogen; R f2 a halogenated alkyl group having 1 to 20 carbon atoms; R f3 is one of -H, -CH3, -CF3, and halogen; R f4 a halogenated alkyl or halogen having 1-20 carbon atoms; R f4 the para-position of the substituted benzene ring, the meta-position of the substituted benzene ring, the ortho-position of the substituted benzene ring, or two or more positions on the substituted benzene ring simultaneously; R f5 -R f8 each independently selected from halogenated alkyls having 1 to 20 carbon atoms; R f9 -R f12 Each is independently selected from halogenated alkyls having 1 to 20 carbon atoms.

2. A method for preparing a block copolymer, characterized in that, Comprising the following steps: Mixing a halogen-containing polymer and a monomer, and preparing the block copolymer according to claim 1 through a polymerization reaction; Or; Mixing a halogen-containing monomer and a polymer, and preparing the block copolymer according to claim 1 through a polymerization reaction.

3. The preparation method according to claim 2, characterized in that, The halogen-containing polymer is poly(1H,1H-perfluorooctyl methacrylate), the monomer is 4-acetoxystyrene, and the block copolymer is poly(p-hydroxystyrene)-b-poly(1H,1H-perfluorooctyl methacrylate); or, the halogen-containing monomer is 1H,1H-perfluorobutyl methacrylate, the polymer is poly(2-vinylpyridine), and the block copolymer is poly(2-vinylpyridine)-b-poly(1H,1H-perfluorobutyl methacrylate).

4. Use of the block copolymer according to claim 1 in the preparation of an organic electronic device.

5. An organic thin film transistor, characterized in that, The organic thin film transistor comprises a substrate, a composite film, an organic semiconductor layer, and a metal electrode which are sequentially stacked. The preparation raw materials of the composite film include the block copolymer according to claim 1 and a functional material, and the functional material is a conductive and / or photosensitive material.

6. The organic thin film transistor according to claim 5, characterized in that, The composite film has a nanostructure, and the particle size of the nanostructure is 5 - 20 nm.

7. The organic thin film transistor according to claim 5, wherein The molar ratio of the block copolymer to the functional material is (1 - 10):

1.

8. The organic thin film transistor according to claim 5, wherein The functional material is an inorganic functional material and / or an organic functional material.

9. The preparation method of the organic thin-film transistor according to any one of claims 5-8, characterized in that, Comprising the following steps: (1) Taking a solution of the block copolymer according to claim 1 and mixing it with a functional material to obtain a mixed solution; (2) Coating the mixed solution on the surface of the substrate, evaporating the solvent, and performing thermal annealing self-assembly to obtain a composite film; (3) Growing an organic semiconductor layer on the surface of the composite film; (4) Growing a metal electrode on the surface of the organic semiconductor layer to obtain the organic thin film transistor.

10. Use of the organic thin film transistor according to any one of claims 5 - 8 in the preparation of a memory, a sensor, and a display device.

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