Polymer semiconductor material with stable photoetching as well as preparation method and application of polymer semiconductor material

Abstract

The invention belongs to the technical field of organic semiconductor materials, and particularly relates to a polymer semiconductor material with stable photoetching as well as a preparation method and application thereof. The polymer semiconductor material disclosed by the invention is a D-A type copolymer PFIDTO-BSe, and the structure of the polymer semiconductor material comprises a biselenophen donor unit and a difluoro indacenone receptor unit. The material has excellent ultraviolet stability: the mobility retention rate gt after irradiation of 365 nm; the solvent resistance is good, and the migration rate retention rate gt is obtained after NMP soaking is conducted for 1000 minutes; 95%. Carrying out Stille coupling to synthesize a polymer; and further preparing an organic field effect transistor array by adopting a photoetching process, namely spin-coating a semiconductor film on the modified substrate, depositing photoresist and patterning, and stripping the photoresist after evaporating a source electrode and a drain electrode. The polymer semiconductor material is compatible with a photoetching process, so that 7-micron channel precision patterning is realized, and the transistor array yield is gt; the method is suitable for manufacturing flexible integrated circuits.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic semiconductor materials, and in particular relates to a polymer semiconductor material and a preparation method and application thereof. Background Art

[0002] As organic field-effect transistors (OFETs) develop toward high-density integration, photolithography has become a core process for large-scale manufacturing of organic integrated circuits (ICs) due to its micron-scale patterning capabilities and compatibility with CMOS processes (Nat Commun. 2020, 11, 1520). However, existing polymer semiconductors face two common technical bottlenecks in photolithography: UV sensitivity: During exposure, UV radiation triggers photochemical reactions in the material (such as degradation or cross-linking), resulting in a carrier mobility attenuation of >50% (Nat. Mater. 2024, 23, 1268); Solvent aggressiveness: Developers (such as tetramethylammonium hydroxide / TMAH), strippers (such as N-methylpyrrolidone / NMP), and photoresist solvents dissolve the semiconductor layer, causing film morphology damage and electrical performance failure (Science 2021, 373, 88). While the indomethacryl thiophene (IDTO) receptor material possesses high electron affinity (patent CN115594827A), its polymers exhibit inherent drawbacks: poor air stability, water and oxygen corrosion leading to threshold voltage drift (>5V), and a lack of photolithography compatibility. Existing IDTO-based bipolar polymers (Macromolecules 2017, 50, 2344; Chem. Commun. 2018, 54, 782) exhibit mobility degradation exceeding 65% after UV exposure, and film dissolution rates exceeding 80% after TMAH development. Therefore, developing bipolar polymer semiconductors with high UV stability, strong solvent resistance, and photolithographic patterning capabilities has become a key requirement for overcoming the barriers to organic integrated circuit manufacturing. Summary of the Invention

[0003] The object of the present invention is to provide a polymer semiconductor material with high ultraviolet stability, high mobility and excellent photolithography compatibility, as well as a preparation method and application thereof.

[0004] The photolithography-stable polymer semiconductor material provided by the present invention adopts a DA-type molecular structure design with diselenophene as a donor and difluoro-substituted indacetone as an acceptor, denoted as PFIDTO-BSe, and its structural formula is shown in the following formula (I):

[0005]

[0006] Here, n is an integer of 50 to 150, preferably n is 80 to 120, and more preferably n is 100.

[0007] The method for preparing the polymer semiconductor material provided by the present invention comprises the following specific steps:

[0008] Under nitrogen protection, the monomer FIDTO-2Br and 5,5'-bis(trimethylstannyl)-2,2'-diselenophene are placed in a solvent for a palladium-catalyzed Stille coupling reaction. After the reaction is completed, a polymer semiconductor material represented by formula (I) is obtained, which is a DA type polymer. The structure of the 5,5'-bis(trimethylstannyl)-2,2'-diselenophene is:

[0009]

[0010] Specifically, under nitrogen environment protection, FIDTO-2Br, 5,5'-bis(trimethylstannyl)-2,2'-diselenophene and palladium catalyst are added to a polymerization bottle at a molar ratio of 1.0:(1.0-1.5):(0.01-0.15), refluxed and stirred at a temperature of 100-150° C. for 10-72 hours, then cooled to room temperature, and the reaction solution is precipitated in ethanol, filtered, and a dark green solid is collected. The target polymer is then purified using a Soxhlet extractor, and the polymer sample is extracted with ethanol, acetone, petroleum ether and chloroform respectively; the chloroform extraction solution is spin-dried to obtain a slightly dark green solid, which is the target polymer;

[0011] Among them, the preferred molar ratio of FIDTO-2Br, 5,5'-bis(trimethylstannyl)-2,2'-diselenophene and palladium catalyst is 1.0:(1.0-1.2):(0.04-0.14), and more preferably 1.0:1.0:0.14.

[0012] Among them, the preferred reaction temperature is 120-135° C., and the reaction time is 40-50 hours; the more preferred reaction temperature is 120° C., and the reaction time is 48 hours.

[0013] The present invention also provides an application of the polymer semiconductor material in preparing an organic field effect transistor, specifically using the PFIDTO-BSe film as a channel charge transport layer in the organic field effect transistor.

[0014] The specific steps of preparing the organic field effect transistor are as follows:

[0015] (1) Preparing a dielectric layer on a silicon wafer and performing surface modification treatment;

[0016] (2) preparing a PFIDTO-BSe semiconductor film on a substrate as a channel charge transport layer;

[0017] (3) preparing a photosensitive layer and patterning it;

[0018] (4) preparing source and drain electrodes as conductive metal layers;

[0019] (5) The photosensitive layer is removed by a stripping agent to obtain an organic field effect transistor array.

[0020] Preferably:

[0021] The dielectric layer in step (1) can be an inorganic material such as silicon dioxide, aluminum oxide, etc., preferably silicon dioxide. The surface modification method includes vacuum vapor phase method, and the modification material used is octadecyltrichlorosilane.

[0022] The channel charge transport layer is prepared in step (2) by spin coating, and the solvent used can be at least one of common organic solvents such as toluene, xylene, chlorobenzene, dichlorobenzene, dichloronaphthalene, trichlorobenzene, chloronaphthalene, etc., preferably chlorobenzene.

[0023] Furthermore, the preferred spin coating process is a two-step spin coating method: in the first step, the spin coating speed is 600-1000 rpm, and the spin coating time is 2-5 seconds; in the second step, the spin coating speed is 1300-1800 rpm, and the spin coating time is 40-80 seconds; then annealing is performed, and the annealing temperature is 140-180° C. and the holding time is 15-35 minutes;

[0024] The photosensitive layer is prepared in step (3) by spin coating, and the photosensitive layer can be a positive photoresist such as AZ series or S18XX series, preferably AZ5214. The patterning process adopts ultraviolet lithography or laser direct writing process, and the lithographic pattern is block-shaped.

[0025] The source and drain electrodes are prepared in step (4) by thermal evaporation, magnetron sputtering, or electron beam evaporation. The material can be gold, silver, aluminum, or other metals; the thickness is 30-40 nm;

[0026] The stripping agent in step (5) can be acetone, N-methylpyrrolidone, Remover PG and other common stripping agents used for stripping positive photoresist.

[0027] The channel precision of the organic field effect transistor array prepared above reaches 7 μm, and the array yield is greater than 98%.

[0028] The present invention constructs a novel polymer semiconductor material with a DA configuration containing a diselenophene donor and a difluoroindacetone acceptor, thereby achieving excellent carrier electrical transport performance. The main molecular design ideas are as follows: (1) The diselenophene donor unit has strong electron-donating ability, excellent molecular planarity and extended conjugated structure, which can effectively improve the highest occupied molecular orbital (HOMO) energy level of the polymer and promote hole injection and transport; (2) The difluoroindole acceptor skeleton contains two carbonyl groups with strong electron-withdrawing properties and two fluorine substitutions, so it has strong electron affinity and low lowest unoccupied molecular orbital (LUMO) energy level, which is conducive to electron injection and transport; (3) The DA combination (diselenophene-difluoroindole) can achieve good energy level matching and intramolecular charge transfer (ICT), which is conducive to the formation of a narrow band gap and enhances the ordered assembly and crystallinity between molecular chains, thereby synergistically improving the carrier mobility; thanks to these synergistic advantages, the thin film field-effect transistor constructed based on the polymer semiconductor material containing diselenophene donor and difluoroindole acceptor exhibits excellent bipolar transport behavior. Among them, the highest hole mobility and electron mobility of PFIDTO-BSe are 2.1 and 0.27 cm 2 V -1 s -1 , fully demonstrating that this type of polymer semiconductor material has broad commercial prospects in optoelectronic devices such as organic thermoelectrics, organic field-effect transistors, organic logic complementary circuits, organic photovoltaics, and organic photodetectors.

[0029] This invention utilizes standard photolithographic processes. Leveraging the inherently excellent etch resistance and environmental stability of polymer semiconductor films, it achieves direct compatibility and efficient integration with photolithographic micro- and nanofabrication techniques. This significantly improves the integration density and manufacturing yield of organic electronic circuits, providing an effective path for industrialized mass production. A key breakthrough in micro- and nanofabrication compatibility, the photolithographic compatibility of polymer semiconductors achieved by this invention enables the precise, on-demand fabrication of complex electronic devices, demonstrating excellent device structural adaptability and process platform versatility.

[0030] The present invention adopts innovative molecular design: a diselenophene structure with high hole transport ability is selected as the donor unit; an alkyl-substituted difluoro IDTO receptor is used as the electron acceptor unit; and for the first time, it is found that the copolymerization of the two produces a synergistic effect: UV-solvent dual stability, under 365nm UV light (intensity 16mW / cm 2 ) after irradiation, the mobility retention rate is greater than 95% (compared with pyrrolopyrrole diketopyrrole polymers <30%); after immersion in stripping solution (NMP) for 1000 minutes, the mobility retention rate is greater than 95% (compared with polymer attenuation >60% under the same conditions); breakthrough in photolithography process compatibility, achieving patterning with 7μm channel accuracy; the yield of the prepared transistor array is greater than 98%.

[0031] Compared with the prior art, the advantages of the present invention are mainly:

[0032] 1. The synthetic technology route of the present invention has the advantages of simplicity, high efficiency, easy availability of raw materials, low cost and strong universality, and is suitable for scale-up synthesis and batch preparation.

[0033] 2. The polymer semiconductor of the present invention is used in thin film FET devices, showing excellent bipolar transmission performance, fully demonstrating its broad commercial prospects in optoelectronic devices.

[0034] 3. The polymer semiconductor material of the present invention has strong UV stability and solvent resistance, and has stability throughout the entire photolithography process.

[0035] 4. The polymer semiconductor material of this invention exhibits excellent environmental stability and process compatibility, allowing seamless integration into the photolithographic microfabrication process used in integrated circuit manufacturing. High-precision patterning can be achieved on this polymer semiconductor to construct complex electronic devices, demonstrating excellent device configuration adaptability. Particularly notably, this material can be stably deployed as the active layer in the lower layers of device structures, effectively overcoming the process bottleneck that limits conventional polymer semiconductors to top-layer structures due to insufficient chemical and mechanical resistance. This material is particularly suitable for the development of novel flexible integrated circuits, providing a scalable manufacturing solution for organic CMOS, display driver, and intelligent sensing systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the infrared spectrum of the polymer semiconductor PFIDTO-BSe in Example 1.

[0037] Figure 2 These are the UV-visible-near-infrared absorption spectra of the polymer semiconductor PFIDTO-BSe in Example 1 in three states: chlorobenzene solution, thin film, and annealed thin film.

[0038] Figure 3 This is the cyclic voltammetry curve of the polymer semiconductor PFIDTO-BSe in Example 2.

[0039] Figure 4 The UV-visible-near-infrared absorption spectra of the polymer semiconductor PFIDTO-BSe film in Example 2 under different illumination durations.

[0040] Figure 5 This is the out-of-plane one-dimensional pattern of grazing incidence X-ray diffraction of the polymer semiconductor PFIDTO-BSe film in Example 2 after different photolithography steps.

[0041] Figure 6This is a schematic diagram of the photolithography process for the active layer of the organic active semiconductor polymer semiconductor PFIDTO-BSe in Example 3. (a) After modifying Si substrate 1 containing SiO2 with octadecyltrichlorosilane 2, a polymer semiconductor film 3 is deposited; (b) a photosensitive layer 4 is directly deposited on the polymer semiconductor film; (c) the photosensitive layer 4 is patterned using a mask 5; (d) a metal electrode layer 6 is deposited on the photosensitive layer; (e) the unexposed photosensitive layer 5 is removed, resulting in the production of an organic field-effect transistor array. (f) is a diagram of the device structure.

[0042] Figure 7 This is an optical microscope photograph of the OFETs transistor array after photolithography of the polymer semiconductor PFIDTO-BSe in Example 3.

[0043] Figure 8 This is a transfer characteristic curve of the OFETs transistor after photolithography of the polymer semiconductor PFIDTO-BSe in Example 3.

[0044] Figure 9 This is a transfer characteristic curve of the OFETs transistor after photolithography of the polymer semiconductor PFIDTO-BSe in Example 4 before and after being placed in the air for 10 days.

[0045] Numbers in the figure: 1-Si substrate containing SiO2, 2-modified layer, 3-active layer, 4-photosensitive layer, 5-mask, 6-metal electrode layer. DETAILED DESCRIPTION

[0046] The present invention will be further described below by way of examples with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following examples.

[0047] Example 1, a polymer semiconductor material having a chemical structure of PFIDTO-BSe - a polymer semiconductor material containing a diselenophene donor, the synthesis route and related tests of which are as follows:

[0048]

[0049] (a) Synthesis of a polymer semiconductor material having the chemical formula PFIDTO-BSe: Under nitrogen atmosphere, 200 mg (0.17 mmol) of 2,7-dibromo-3,8-bis(2-decyltetradecyl)5,10-difluoro-indacene[1,2-b:5,6-b']dithiophene-4,9-dione (FIDTO-2Br), 99.5 mg (0.17 mmol) of 5,5'-bis(trimethylstannyl)-2,2'-bithiophene, 9.8 mg (0.014 mmol) of bis(triphenylphosphine)palladium dichloride, and 3 mL of chlorobenzene were added to a polymerization flask. The flask was subjected to three freeze-evacuation-thaw cycles for deoxygenation. The reaction mixture was then heated to 100°C and refluxed with stirring for 54 hours. The mixture was then cooled to room temperature and the reaction solution was poured into ethanol, stirred at room temperature for two hours, and filtered. The resulting polymer was extracted using a Soxhlet extractor. The product was extracted with ethanol, acetone and petroleum ether in sequence until colorless to remove small molecules and catalysts, and then extracted with chloroform to obtain the final product with a yield of 85%.

[0050] (b) Determination of the absorption spectrum of the target product: Figure 1 As shown, the polymer PFIDTO-BSe exhibits a wide absorption range in chlorobenzene solution, thin film and annealed thin film states. The spectral absorption range is approximately 320-1015 nm, and the strongest absorption peaks in the three states are 529 nm, 533 nm, and 541 nm, respectively.

[0051] (c) Electrochemical properties of the target product: Figure 2 As shown, the HOMO and LUMO energy levels of PFIDTO-BSe are –5.75 eV / –3.54 eV.

[0052] Example 2, a polymer semiconductor material having a chemical structure of PFIDTO-BSe - a polymer semiconductor material containing a diselenophene donor, the synthesis route and related tests of which are as follows:

[0053]

[0054] (a) Synthesis of a polymer semiconductor material having the chemical formula PFIDTO-BSe: Under nitrogen atmosphere, 200 mg (0.17 mmol) of 2,7-dibromo-3,8-bis(2-decyltetradecyl)5,10-difluoro-indacene[1,2-b:5,6-b']dithiophene-4,9-dione (FIDTO-2Br), 99.5 mg (0.17 mmol) of 5,5'-bis(trimethylstannyl)-2,2'-bithiophene, 9 mg (0.01 mmol) of trisdibenzylideneacetone dipalladium, and 3 mL of dichlorobenzene were added to a polymerization flask. The flask was subjected to three freeze-evacuation-thaw cycles for deoxygenation. The reaction mixture was then heated to 120°C and refluxed with stirring for 48 hours, then cooled to room temperature, and the reaction solution was precipitated in ethanol, stirred at room temperature for two hours, and filtered. The resulting polymer was extracted using a Soxhlet extractor. The product was extracted with ethanol, acetone and petroleum ether in sequence until colorless to remove small molecules and catalysts, and then extracted with chloroform to obtain the final product with a yield of 92%.

[0055] Molecular weight characterization data: weight average molecular weight is 87.7kDa, number average molecular weight is 42.7kDa, and polymer molecular weight distribution index is 2.05; infrared spectrum characterization characteristic peak: νC=O, 1710cm –1 .

[0056] (b) Determination of target product by infrared spectrum, see Figure 3 As shown, at wave number 1710 cm –1 A carbonyl (C=O) characteristic peak appeared, corresponding to the carbonyl characteristic peak in the polymer PFIDTO-BSe.

[0057] (c) Characterization of polymer semiconductors with full stability throughout the photolithography process, specifically: measuring the absorption spectra of PFIDTO-BSe films under UV irradiation for different durations, see Figure 4 As shown, the absorption peak remains almost unchanged, and the chemical properties are stable under ultraviolet light;

[0058] (d) Characterization of polymer semiconductors with full stability during the lithography process: After the PFIDTO-BSe film has undergone different lithography processes, the film is subjected to grazing incidence X-ray diffraction testing, such as Figure 5 As shown, after exposure, development, and stripper immersion, the out-of-plane stacking of the film remains almost unchanged, still showing ordered lamellar peaks, and the in-plane π-π stacking remains stable.

[0059] Example 3, preparation of organic thin film transistor array compatible with photolithography process, the process is as follows Figure 6 As shown, the specific steps are:

[0060] (a) A silicon wafer is used as the substrate, and 300nm thermally grown silicon dioxide is used as the dielectric layer. The silicon wafer with silicon dioxide is placed in a mixture of concentrated sulfuric acid and hydrogen peroxide (volume ratio = 1:2) and soaked on a 60℃ hot plate for 30 minutes to remove organic residues on the surface. After soaking, it is ultrasonically cleaned with deionized water and ethanol and blown dry with high-purity nitrogen. The cleaned and dried silicon wafer is placed in a clean petri dish, and a small amount of octadecyltrichlorosilane is drawn with a capillary tube and dropped into the center of the petri dish. It is then immediately placed in a vacuum oven. Evacuate to a vacuum, heat to 120℃ and keep warm for 3 hours to complete the preparation of the modified layer. Then, ultrasonically clean it in n-hexane, ethanol, and chloroform in sequence and blown dry with high-purity nitrogen.

[0061] (b) The PFIDTO-BSe prepared in Example 2 was used as the semiconductor active layer. A 5 mg / ml chlorobenzene solution was prepared and heated on a hot plate at 50°C for 4 hours. A thin film was then deposited on the silicon wafer modified in step (a) using a two-step spin coating process (800 rpm / min for 3 seconds; 1500 rpm / min for 60 seconds). The film was then annealed in a vacuum oven at 160°C for 25 minutes.

[0062] (c) AZ5214 photoresist was spin-coated on the organic film from step (b) at a spin-coating speed of 600 rpm / min for 6 seconds and 2000 rpm / min for 40 seconds. The film was then placed on a 110°C hot plate for 1 minute. A UV lithography machine was used to align the mask and expose the film for 7 seconds. The film was then developed with 10% tetramethylammonium hydroxide (TMAH) for 30 seconds. After development, the film was rinsed with deionized water and dried with a high-purity nitrogen gun.

[0063] (d) The patterned sample was deposited with 35 nm thick gold electrodes as source and drain electrodes using vacuum thermal evaporation. The sample was then immersed in acetone solution for lift-off.

[0064] Figure 7 This is an optical microscope photograph of the OFETs transistor array after photolithography of the polymer semiconductor PFIDTO-BSe.

[0065] (e) The semiconductor characteristics of the obtained OFETs device were measured using the FS-Pro380 semiconductor tester, and its typical output curve is shown in Figure 2. Figure 8 As shown. Among them, the hole and electron mobility in the saturation region of the device is calculated by the following equations: DS =(W / 2L)C iμ (V G –V T ) 2 (Saturation region, V DS =V G –V T ). Among them, IDS is the drain current, μ is the carrier mobility, V G is the gate voltage, V T is the threshold voltage, C i is the insulator capacitance, W / L=50 / 7μm.

[0066] Figure 8 The transfer characteristic curve of the OFET device prepared in Example 3 of the present invention with the polymer PFIDTO-BSe as the semiconductor layer shows good P-type device performance, and its electron mobility is 2.1cm 2 / V s, the switching current ratio is greater than 10 3 .

[0067] Example 4, preparation of an organic thin film transistor array compatible with photolithography process, the specific steps are as follows:

[0068] (a) A silicon wafer is used as the substrate, and 300nm thermally grown silicon dioxide is used as the dielectric layer. The silicon wafer with silicon dioxide is placed in a mixture of concentrated sulfuric acid and hydrogen peroxide (volume ratio = 1:2) and soaked on a 60℃ hot plate for 30 minutes to remove organic residues on the surface. After soaking, it is ultrasonically cleaned with deionized water and ethanol and blown dry with high-purity nitrogen. The cleaned and dried silicon wafer is placed in a clean petri dish, and a small amount of octadecyltrichlorosilane is drawn with a capillary tube and dropped into the center of the petri dish. It is then immediately placed in a vacuum oven. Evacuate to a vacuum, heat to 120℃ and keep warm for 3 hours to complete the preparation of the modified layer. Then, ultrasonically clean it in n-hexane, ethanol, and chloroform in sequence and blown dry with high-purity nitrogen.

[0069] (b) The PFIDTO-BSe prepared in Example 1 was used as the semiconductor active layer. A 5 mg / ml chlorobenzene solution was prepared and heated on a hot plate at 50°C for 4 hours. A thin film was then deposited on the silicon wafer modified in step (a) using a two-step spin coating process (800 rpm / min for 3 seconds; 1500 rpm / min for 60 seconds). The film was then annealed in a vacuum oven at 160°C for 25 minutes.

[0070] (c) AZ5214 photoresist was spin-coated on the organic film from step (b) at a spin-coating speed of 600 rpm / min for 6 seconds and 2000 rpm / min for 40 seconds. The film was then placed on a 110°C hot plate for 1 minute. A UV lithography machine was used to align the mask and expose the film for 7 seconds. The film was then developed with 10% tetramethylammonium hydroxide (TMAH) for 30 seconds. After development, the film was rinsed with deionized water and dried with a high-purity nitrogen gun.

[0071] (d) The patterned sample was deposited with 35 nm thick gold electrodes as source and drain electrodes using vacuum thermal evaporation. The sample was then immersed in acetone solution for lift-off.

[0072] (e) The semiconductor characteristics of the obtained OFETs device were measured using the FS-Pro380 semiconductor tester. After being placed in the air for ten days, the semiconductor characteristics of the obtained OFETs device were measured again using the FS-Pro380 semiconductor tester. The typical output curve is shown in FIG. Figure 9 shown.

[0073] Figure 9 The transfer characteristic curves of the OFET device with polymer PFIDTO-BSe as the semiconductor layer prepared by Example 4 of the present invention before and after being placed in air for ten days, the device shows good P-type device performance (on-off current ratio greater than 10 3 ), the device showed good air stability, and the performance before and after placement remained above 94%.

[0074] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any modification or equivalent replacement of the above embodiment made by any person skilled in the art according to the technical solution of the present invention shall still fall within the scope of protection of the present invention.

Claims

1. A lithographically stable polymer semiconductor material, characterized in that A DA-type molecular structure design using diselenophene as a donor and difluoro-substituted indacetone as an acceptor is denoted as PFIDTO-BSe, and its structural formula is shown in the following formula (I): Here, n is an integer from 50 to 150.

2. The method for preparing a polymer semiconductor material according to claim 1, wherein: The specific steps are: Under nitrogen protection, the monomer FIDTO-2Br and 5,5'-bis(trimethylstannyl)-2,2'-diselenophene are placed in a solvent for a palladium-catalyzed Stille coupling reaction. After the reaction is completed, a polymer semiconductor material represented by formula (I) is obtained. The structure of the 5,5'-bis(trimethylstannyl)-2,2'-diselenophene is:

3. The preparation method according to claim 2, characterized in that Specifically, under nitrogen environment protection, FIDTO-2Br, 5,5'-bis(trimethylstannyl)-2,2'-diselenophene and palladium catalyst are added to a polymerization bottle at a molar ratio of 1.0:(1.0~1.5):(0.01~0.15), refluxed and stirred at a temperature of 100~150°C for 10~72 hours, and then cooled to room temperature. The reaction solution is precipitated in ethanol, filtered, and the dark green solid is collected. The target polymer is then purified by a Soxhlet extractor, and the polymer samples are extracted with ethanol, acetone, petroleum ether and chloroform respectively; the chloroform extraction solution is spin-dried to obtain a slightly dark green solid, which is the target polymer.

4. Use of the polymer semiconductor material according to claim 1 in preparing an organic field effect transistor, specifically using the PFIDTO-BSe thin film as a channel charge transport layer in the organic field effect transistor.

5. The use according to claim 4, characterized in that The specific steps of preparing the organic field effect transistor are: (1) Preparing a dielectric layer on a silicon wafer and performing surface modification treatment; (2) preparing a PFIDTO-BSe semiconductor film on a substrate as a channel charge transport layer; (3) preparing a photosensitive layer and patterning it; (4) preparing source and drain electrodes as conductive metal layers; (5) The photosensitive layer is removed by a stripping agent to obtain an organic field effect transistor array.

6. The use according to claim 5, characterized in that: In step (1), the dielectric layer is made of silicon dioxide or aluminum oxide; the surface modification treatment is performed by vacuum vapor phase method, and the modification material is octadecyltrichlorosilane; In step (2), the channel charge transport layer is prepared by spin coating, and the solvent used is at least one of toluene, xylene, chlorobenzene, dichlorobenzene, dichloronaphthalene, trichlorobenzene, and chloronaphthalene; In step (3), the photosensitive layer is prepared by spin coating, and the photosensitive layer material is AZ series or S18XX series positive photoresist; the patterning process adopts ultraviolet lithography process or laser direct writing process, and the lithographic pattern is block-shaped; In step (4), the source and drain electrodes are prepared by thermal evaporation, magnetron sputtering or electron beam evaporation; the material is gold, silver or aluminum; the thickness is 30 to 40 nm; In step (5), the stripping agent is acetone, N-methylpyrrolidone or Remover PG.

7. The use according to claim 6, characterized in that The preferred spin coating process in step (2) is a two-step spin coating method: in the first step, the spin coating speed is 600-1000 rpm, and the spin coating time is 2-5 seconds; in the second step, the spin coating speed is 1300-1800 rpm, and the spin coating time is 40-80 seconds; and then annealing is performed at an annealing temperature of 140-180° C. and a holding time of 15-35 minutes.

8. An organic field effect transistor array, characterized in that: The channel charge transport layer adopts a thin film prepared from the polymer semiconductor material according to claim 1. 9 . The organic field effect transistor array according to claim 8 , wherein the channel precision is 7 μm and the yield is greater than 98%.

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