High-temperature-resistant polyimide dielectric film and preparation method thereof

Abstract

The invention provides a high-temperature-resistant polyimide dielectric film and a preparation method thereof. The preparation method comprises the following steps: firstly, respectively dissolving dianhydride and diamine in a solvent to obtain a mixed solution 1 and a mixed solution 2; further uniformly mixing the mixed solution 1 and the mixed solution 2 to obtain a mixed solution 3; then, dissolving an organic semiconductor in a solvent 3, and stirring for 2 hours to obtain a mixed solution 4; gradually adding the mixed solution 4 into the mixed solution 3 to obtain a mixed solution 5, stirring the mixed solution 5 for 30 minutes, and performing ultrasonic treatment for 2 hours; uniformly dispensing the obtained mixed solution 5 on a clean glass sheet; then carrying out thermal imidization treatment on the mixed solution 5 on the glass sheet; after thermal imidization is completed, the mixed solution 5 forms a film on a glass sheet, and the film is dried in a vacuum oven to obtain the film; the invention develops a polyimide dielectric material with high thermal stability and high energy density so as to break through the limitation of a high-temperature environment on the application of a thin-film capacitor.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature dielectric films, and particularly relates to a high-temperature resistant polyimide dielectric film and a preparation method thereof. Background Art

[0002] Dielectric film capacitors are key energy storage components in power and electronic systems. Due to their advantages such as high power density, fast charge and discharge speed, and long cycle life, they are widely used in fields such as electric vehicles, new energy power generation, and pulsed weapons. Polymer dielectrics have excellent mechanical properties, high flexibility, and light weight, which can meet the lightweight requirements. However, their low dielectric constant limits their practical applications. Among the currently commonly used polymer dielectric materials, polyimide (PI) has been widely used because the molecular chain contains an imide ring, which has excellent mechanical properties and insulation properties. However, with the increasing requirements for device miniaturization and lightweight, as well as the emergence of harsh application scenarios, electrostatic energy storage technology faces higher requirements. Therefore, developing polyimide dielectric materials with high thermal stability and high energy density has become an urgent problem to be solved in order to break through the limitations of the application of thin film capacitors in high-temperature environments. Summary of the Invention

[0003] Aiming at the problems existing in the prior art, the present invention constructs an inhibition mechanism of charge migration by introducing organic small molecules into the polyimide matrix, significantly reducing the conductance loss and leakage current, thereby improving the high-temperature resistance performance, energy storage performance, and insulation performance of the material.

[0004] To achieve the above technology, the present invention provides a high-temperature resistant polyimide dielectric film and a preparation method thereof. The preparation method is as follows:

[0005] (1) First, dissolve the dianhydride in solvent 1 to obtain mixed solution 1, and dissolve the diamine in solvent 2 to obtain mixed solution 2;

[0006] (2) Further mix and stir mixed solution 1 and mixed solution 2 for 12 hours to obtain mixed solution 3;

[0007] (3) Then, dissolve the organic semiconductor in solvent 3 and stir for 2 hours to obtain mixed solution 4;

[0008] (4) Subsequently, gradually add mixed solution 4 to mixed solution 3 to obtain mixed solution 5. After stirring mixed solution 5 for 30 minutes, perform ultrasonic treatment for 2 hours;

[0009] (5) Then, evenly drop the obtained mixed solution 5 onto a clean glass slide;

[0010] (6) Then, perform thermal imidization treatment on the mixed solution 5 on the glass slide;

[0011] (7) After the thermal imidization is completed, the mixed solution 5 is formed into a film on a glass slide. The glass slide is immersed in deionized water, and the film is peeled off from the glass slide.

[0012] (8) The film is dried in a vacuum oven to completely remove the residual moisture, and a film is obtained.

[0013] The dianhydride is one or more of 4,4'-oxybisphthalic anhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, bisphenol A type diether dianhydride, pyromellitic dianhydride, trans-hydrogenated trimellitic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride; the diamine is one or more of 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 2,2'-bis(trifluoromethyl)-4,4'-diaminophenyl ether, 4,4'-[1,4-phenylenebis(oxy)]bis[3-(trifluoromethyl)aniline], 1,3-bis(4'-aminophenoxy)benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane.

[0014] In step (1), the solvent 1, solvent 2 and solvent 3 are one of N-methylpyrrolidone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide.

[0015] Further, the molar ratio of the dianhydride to the diamine monomer is 1:1.

[0016] Further, the organic semiconductor is one or more of perfluorohexacyanoanthraquinone with a high electron affinity of 5.37 eV, tetrafluoro-7,7,8,8-tetracyanoquinodimethane with a high electron affinity of 5.24 eV, difluoro-7,7,8,8-tetracyanoquinodimethane with a high electron affinity of 4.59 eV.

[0017] Further, the solid content of the organic semiconductor in the mixed solution 4 is 30-80%, and the added amount of the mixed solution 4 is 0.1-1.0% of the volume ratio of the mixed solution 3.

[0018] Further, the thermal imidization process is as follows: first, it is dried at 80°C for 12 hours to completely remove the solvent; then it is heated at 150°C, 200°C and 250°C for 1 hour each to ensure that the polymer is fully imidized.

[0019] Further, the film thickness is controlled between 10-12 μm.

[0020] Further, the dianhydride and the diamine are both from Tokyo Chemical Industry Co., Ltd. in Japan, the organic semiconductor is from 1-Material Co., Ltd. in Canada, and the solvent is from Sigma Co., Ltd.

[0021] Further, a high-temperature resistant polyimide dielectric film.

[0022] The beneficial effects of the present invention are as follows: The polyimide polymer prepared from commercial dianhydride and diamine has excellent mechanical properties and electrical insulation characteristics, but its energy storage density at 200 °C is relatively low. Incorporating an organic semiconductor with a high electron affinity into the matrix can cause partial charge transfer between it and the polymer chain to form a charge transfer complex, which has an important impact on the electron transport in the chain, and thus significantly affects the energy storage performance of the composite material at high temperatures. By incorporating an organic semiconductor with a high electron affinity into the polymer matrix, a large number of deep traps can be effectively introduced to limit charge migration, thereby improving the insulation performance of the composite material. The organic semiconductors selected in the present invention exhibit excellent thermal stability below 300 °C. And due to their strong electron acceptor characteristics, these organic semiconductors can effectively accept electrons from donor materials and have been widely used in organic solar cells to improve charge separation efficiency and device performance.

[0023] Compared with the pure polyimide film, the dielectric constant of the composite film incorporated with the organic semiconductor has a slight increase, which is mainly attributed to the additional dipole moment introduced by the partial charge transfer between the organic semiconductor and the polymer. In addition, the dielectric loss of all samples remains at a low level throughout the frequency and temperature range, always lower than 1%, indicating that the energy loss during the energy storage process of the material is small, which helps to improve the energy storage efficiency of the dielectric. Specific embodiments

[0024] Comparative example 1

[0025] A high-temperature resistant polyimide dielectric film and its preparation method are as follows:

[0026] (1) First, 0.1 mmol of 4,4'-(hexafluoroisopropylidene) diphthalic anhydride and 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether are respectively dissolved in 5 mL of N-methylpyrrolidone. The molar ratio of dianhydride to diamine monomer is 1:1, and the total monomer mass is 300 mg;

[0027] (2) After the two monomers are completely dissolved, the mixed solution is stirred for 12 hours to promote the full reaction of the monomers to form a polyamic acid solution;

[0028] (3) Then, the obtained mixed solution is uniformly drop-coated on a clean glass slide to prevent the interference of impurity introduction on the film-forming process;

[0029] (4) Then, the polymer on the glass slide is subjected to thermal imidization treatment according to the procedure: first dried at 80 °C for 12 hours to completely remove the N-methylpyrrolidone solvent; then heated at 150 °C, 200 °C, and 250 °C for 1 hour each to ensure the full imidization of the polymer;

[0030] (5) After the thermal imidization is completed, the film is immersed in deionized water, peeled off from the glass slide, and then dried in a vacuum oven at 100 °C to completely remove the residual moisture. The final thickness of the film used for electrical characterization is 10 μm.

[0031] Example 1

[0032] A high-temperature resistant polyimide dielectric film and its preparation method are as follows:

[0033] (1) First, 0.1 mmol of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl ether are respectively dissolved in 5 mL of N-methylpyrrolidone. The molar ratio of the dianhydride to the diamine monomer is 1:1, and the total monomer mass is 300 mg.

[0034] (2) When the two monomers are completely dissolved, the mixed solution is stirred for 12 hours to promote the full reaction of the monomers to form a polyamic acid solution.

[0035] (3) Then, the organic semiconductor perfluorohexacyanonaphthoquinone is dissolved in N-methylpyrrolidone, keeping the solid content at 50%, and stirred for 2 hours to ensure its complete dissolution and form a stable dispersion.

[0036] (4) Subsequently, these organic semiconductor solutions are gradually added to the polyamic acid solution at a volume ratio of 0.1%. To ensure the uniform distribution of the dopant in the polymer matrix, the mixed solution is ultrasonically treated for 2 hours after stirring for 30 minutes to avoid the agglomeration and sedimentation of the semiconductor.

[0037] (5) Then, the obtained mixed solution is evenly drop-coated on a clean glass slide to prevent the introduction of impurities from interfering with the film-forming process.

[0038] (6) Then, the polymer on the glass slide is subjected to thermal imidization treatment according to the procedure: first dried at 80 °C for 12 hours to completely remove the N-methylpyrrolidone solvent; then heated at 150 °C, 200 °C, and 250 °C for 1 hour each to ensure the full imidization of the polymer.

[0039] (7) After the thermal imidization is completed, the film is immersed in deionized water, peeled off from the glass slide, and then dried in a vacuum oven at 100 °C to completely remove the residual moisture. The final thickness of the film used for electrical characterization is 10 μm.

[0040] Example 2

[0041] A high-temperature resistant polyimide dielectric film and its preparation method are as follows:

[0042] (1) First, 0.1 mmol of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride and 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether were separately dissolved in 5 mL of N-methylpyrrolidone. The molar ratio of the dianhydride to the diamine monomer was 1:1, and the total monomer mass was 300 mg;

[0043] (2) After the two monomers were completely dissolved, the mixed solution was stirred for 12 hours to promote the full reaction of the monomers to form a polyamic acid solution;

[0044] (3) Then, the organic semiconductor tetrafluoro-7,7,8,8-tetracyanoquinodimethane was dissolved in N-methylpyrrolidone, maintaining a solid content of 50%, and stirred for 2 hours to ensure its complete dissolution and form a stable dispersion;

[0045] (4) Subsequently, these organic semiconductor solutions were gradually added to the polyamic acid solution at a volume ratio of 0.1%. To ensure the uniform distribution of the dopant in the polymer matrix, the mixed solution was ultrasonically treated for 2 hours after stirring for 30 minutes to avoid the agglomeration and sedimentation of the semiconductor;

[0046] (5) Then, the obtained mixed solution was evenly drop-coated on a clean glass slide to prevent the introduction of impurities from interfering with the film-forming process;

[0047] (6) Then, the polymer on the glass slide was subjected to thermal imidization treatment according to the procedure: first dried at 80 °C for 12 hours to completely remove the N-methylpyrrolidone solvent; then heated at 150 °C, 200 °C, and 250 °C for 1 hour each to ensure the full imidization of the polymer;

[0048] (7) After the thermal imidization was completed, the film was immersed in deionized water, the film was peeled off from the glass slide, and then dried in a vacuum oven at 100 °C to completely remove the residual moisture. The final film thickness for electrical characterization was 10 μm.

[0049] Example 3

[0050] A high-temperature resistant polyimide dielectric film and its preparation method are as follows:

[0051] (1) First, 0.1 mmol of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride and 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether were separately dissolved in 5 mL of N-methylpyrrolidone. The molar ratio of the dianhydride to the diamine monomer was 1:1, and the total monomer mass was 300 mg;

[0052] (2) After the two monomers were completely dissolved, the mixed solution was stirred for 12 hours to promote the full reaction of the monomers to form a polyamic acid solution;

[0053] (3) Then, dissolve the organic semiconductor difluoro-7,7,8,8-tetracyanoquinodimethane in N-methylpyrrolidone, maintaining a solid content of 50%, and stir for 2 hours to ensure its complete dissolution and the formation of a stable dispersion;

[0054] (4) Subsequently, gradually add these organic semiconductor solutions to the polyamic acid solution according to a volume ratio of 0.1%. To ensure the uniform distribution of the dopant in the polymer matrix, the mixed solution is ultrasonically treated for 2 hours after stirring for 30 minutes to avoid the agglomeration and sedimentation of the semiconductor;

[0055] (5) Then, evenly drop the obtained mixed solution onto a clean glass slide to prevent the introduction of impurities from interfering with the film-forming process;

[0056] (6) Then, perform thermal imidization treatment on the polymer on the glass slide according to the procedure: first dry it at 80 °C for 12 hours to completely remove the N-methylpyrrolidone solvent; then heat it at 150 °C, 200 °C, and 250 °C for 1 hour each to ensure the full imidization of the polymer;

[0057] (7) After the thermal imidization is completed, soak the film in deionized water, peel the film from the glass slide, and then dry it in a vacuum oven at 100 °C to completely remove the residual moisture. The final thickness of the film used for electrical characterization is 10 μm.

[0058] Example 4

[0059] A high-temperature resistant polyimide dielectric film and its preparation method are as follows:

[0060] (1) First, dissolve 0.1 mmol of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl ether in 5 mL of N-methylpyrrolidone respectively. The molar ratio of the dianhydride to the diamine monomer is 1:1, and the total monomer mass is 300 mg;

[0061] (2) After the two monomers are completely dissolved, mix the solutions and stir for 12 hours to promote the full reaction of the monomers to form a polyamic acid solution;

[0062] (3) Then, dissolve the organic semiconductor perfluorohexacyanonaphthoquinone in N-methylpyrrolidone, maintaining a solid content of 50%, and stir for 2 hours to ensure its complete dissolution and the formation of a stable dispersion;

[0063] (4) Subsequently, gradually add these organic semiconductor solutions to the polyamic acid solution according to a volume ratio of 0.3%. To ensure the uniform distribution of the dopant in the polymer matrix, the mixed solution is ultrasonically treated for 2 hours after stirring for 30 minutes to avoid the agglomeration and sedimentation of the semiconductor;

[0064] (5) Then, the obtained mixed solution was evenly drop-coated on a clean glass slide to prevent the introduction of impurities from interfering with the film-forming process;

[0065] (6) Then, the polymer on the glass slide was subjected to thermal imidization treatment according to the procedure: first dried at 80 °C for 12 hours to thoroughly remove the N-methylpyrrolidone solvent; then heated at 150 °C, 200 °C, and 250 °C for 1 hour each to ensure that the polymer was fully imidized;

[0066] (7) After the thermal imidization was completed, the film was soaked in deionized water, peeled off from the glass slide, and then dried in a vacuum oven at 100 °C to completely remove the residual moisture. The final thickness of the film for electrical characterization was 10 μm.

[0067] Example 5

[0068] A high-temperature resistant polyimide dielectric film and its preparation method are as follows:

[0069] (1) First, 0.1 mmol of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl ether were respectively dissolved in 5 mL of N-methylpyrrolidone. The molar ratio of the dianhydride to the diamine monomer was 1:1, and the total monomer mass was 300 mg;

[0070] (2) After the two monomers were completely dissolved, the mixed solution was stirred for 12 hours to promote the full reaction of the monomers to form a polyamic acid solution;

[0071] (3) Then, the organic semiconductor perfluorohexacyanonaphthoquinone was dissolved in N-methylpyrrolidone, keeping the solid content at 50%, and stirred for 2 hours to ensure its complete dissolution and form a stable dispersion;

[0072] (4) Subsequently, these organic semiconductor solutions were gradually added to the polyamic acid solution at a volume ratio of 0.5%. To ensure the uniform distribution of the dopant in the polymer matrix, the mixed solution was ultrasonically treated for 2 hours after stirring for 30 minutes to avoid the agglomeration and sedimentation of the semiconductor;

[0073] (5) Then, the obtained mixed solution was evenly drop-coated on a clean glass slide to prevent the introduction of impurities from interfering with the film-forming process;

[0074] (6) Then, the polymer on the glass slide was subjected to thermal imidization treatment according to the procedure: first dried at 80 °C for 12 hours to thoroughly remove the N-methylpyrrolidone solvent; then heated at 150 °C, 200 °C, and 250 °C for 1 hour each to ensure that the polymer was fully imidized;

[0075] (7) After the thermal imidization is completed, the film is immersed in deionized water, peeled off from the glass slide, and then dried in a vacuum oven at 100 °C to completely remove the residual moisture. The final thickness of the film used for electrical characterization is 10 μm.

[0076] Example 6

[0077] A high-temperature resistant polyimide dielectric film and its preparation method are as follows:

[0078] (1) First, 0.1 mmol of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 4,4'-[1,4-phenylenebis(oxy)]bis[3-(trifluoromethyl)aniline] are respectively dissolved in 5 mL of dimethylformamide. The molar ratio of dianhydride to diamine monomer is 1:1, and the total monomer mass is 300 mg;

[0079] (2) When the two monomers are completely dissolved, the mixed solution is stirred for 12 hours to promote the full reaction of the monomers to form a polyamic acid solution;

[0080] (3) Then, the organic semiconductor perfluorohexacyanoquinone is dissolved in dimethylformamide, keeping the solid content at 50%, and stirred for 2 hours to ensure its complete dissolution and form a stable dispersion;

[0081] (4) Subsequently, these organic semiconductor solutions are gradually added to the polyamic acid solution according to a volume ratio of 0.8%. To ensure the uniform distribution of the dopant in the polymer matrix, the mixed solution is ultrasonically treated for 2 hours after stirring for 30 minutes to avoid the agglomeration and sedimentation of the semiconductor;

[0082] (5) Then, the obtained mixed solution is evenly drop-coated on a clean glass slide to prevent the introduction of impurities from interfering with the film-forming process;

[0083] (6) Then, the polymer on the glass slide is subjected to thermal imidization treatment according to the procedure: first dried at 80 °C for 12 hours to completely remove the dimethylformamide solvent; then heated at 150 °C, 200 °C, and 250 °C for 1 hour each to ensure the full imidization of the polymer;

[0084] (7) After the thermal imidization is completed, the film is immersed in deionized water, peeled off from the glass slide, and then dried in a vacuum oven at 100 °C to completely remove the residual moisture. The final thickness of the film used for electrical characterization is 10 μm.

[0085] Example 7

[0086] A high-temperature resistant polyimide dielectric film and its preparation method are as follows:

[0087] (2) First, 0.1 mmol of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 4,4'-[1,4-phenylenebis(oxy)]bis[3-(trifluoromethyl)aniline] were separately dissolved in 5 mL of dimethylformamide. The molar ratio of the dianhydride to the diamine monomer was 1:1, and the total monomer mass was 300 mg;

[0088] (3) After the two monomers were completely dissolved, the mixed solution was stirred for 12 hours to promote the full reaction of the monomers to form a polyamic acid solution;

[0089] (3) Then, the organic semiconductor perfluorohexacyanonaphthoquinone was dissolved in dimethylformamide, keeping the solid content at 50%, and stirred for 2 hours to ensure its complete dissolution and form a stable dispersion;

[0090] (4) Subsequently, these organic semiconductor solutions were gradually added to the polyamic acid solution at a volume ratio of 1.0%. To ensure the uniform distribution of the dopant in the polymer matrix, the mixed solution was ultrasonicated for 2 hours after stirring for 30 minutes to avoid the agglomeration and sedimentation of the semiconductor;

[0091] (5) Then, the obtained mixed solution was evenly drop-coated on a clean glass slide to prevent the introduction of impurities from interfering with the film-forming process;

[0092] (6) Then, the polymer on the glass slide was subjected to thermal imidization treatment according to the procedure: first dried at 80 °C for 12 hours to completely remove the dimethylformamide solvent; then heated at 150 °C, 200 °C, and 250 °C for 1 hour each to ensure the full imidization of the polymer;

[0093] (7) After the thermal imidization was completed, the film was soaked in deionized water, the film was peeled off from the glass slide, and then dried in a vacuum oven at 100 °C to completely remove the residual moisture. The final thickness of the film for electrical characterization was 10 μm.

[0094] The above comparative examples and examples were tested, and the test results are shown in Tables 1 and 2:

[0095] 1. The glass transition temperature (Tg) of the test sample was measured by a DSC-Q8000 differential scanning calorimeter (DSC) of TA Instruments. The test process included three heating and cooling cycles, and the temperature change rate was 10 °C / min. To eliminate the thermal history of the sample, the data of the third thermal cycle was used to calculate the Tg of the sample.

[0096] 2. The energy band structure of the sample was characterized by ultraviolet-visible spectroscopy (UV-vis) in the wavelength range of 200 - 700 nm using a Hitachi U-3010 spectrophotometer, and the wavelength accuracy of the test was ±0.3 nm.

[0097] 3. The Young's modulus of the sample was tested using an Instron 34SC-1 bench-top tensile testing machine. The test sample was a long-strip thin film with a thickness of 10 μm and a width of 10 mm.

[0098] 4. The steps for testing the dielectric properties of the sample are as follows: First, gold electrodes with a diameter of 10 mm and a thickness of 60 nm were sputtered on both sides of the thin film. Subsequently, a broadband dielectric spectrometer (Novocontrol Concept 80) and a Quatro-Cryosystem temperature control system were used to test the dielectric spectrum of the sample at 10 2 ~10 6 Hz, and at the same time, by precisely controlling the oven temperature in the range of 25 - 250 °C, the dielectric constant and dielectric loss of the sample were obtained.

[0099] 5. To evaluate the effect of the sample in terms of high-temperature insulation performance, a TREK 610C amplifier was used to measure the breakdown field strength of the sample, that is, a voltage was applied to the sample at a DC boost rate of 500 V / s until electrical breakdown occurred. To ensure the reliability of the results, each sample was tested at least 20 times. The test results were analyzed using a two-parameter Weibull statistical method to determine the high-temperature breakdown strength (Eb) of the sample and obtain the shape parameter β indicating the breakdown stability of the y sample. Higher Eb and β values mean that the dielectric polymer has higher breakdown strength and stability, which means that the sample has higher breakdown reliability at high temperatures and can maintain stable insulation performance even under extreme conditions.

[0100] 6. To prove the high-temperature energy storage performance of the sample, an electric displacement - electric field strength cyclic test was carried out on the sample at a temperature of 200 °C and a frequency of 100 Hz. The discharge energy density of the sample was obtained by integrating the electric hysteresis loop of the sample. The higher the discharge energy density, the better the high-temperature energy storage performance.

[0101] Table 1

[0102]

[0103] Table 2

[0104]

[0105] From the comparison data of the comparative examples and the examples, it can be seen that adding a certain content of organic semiconductor to polyimide has little effect on the glass transition temperature and mechanical properties of polyimide. While maintaining excellent mechanical properties, the dielectric constant, high-temperature energy storage performance, and high-temperature insulation performance of polyimide are improved, so as to expand the application of polyimide as a high-temperature dielectric material.

Claims

1. A high temperature resistant polyimide dielectric film and a preparation method thereof, characterized in that: The preparation method is as follows: (1) firstly, dissolving dianhydride in solvent 1 to obtain mixed solution 1, and dissolving diamine in solvent 2 to obtain mixed solution 2; (2) further mixing the mixed solution 1 and the mixed solution 2 and stirring for 12 hours to obtain a mixed solution 3; (3) Then, the organic semiconductor is dissolved in the solvent 3 and stirred for 2 hours to obtain a mixed solution 4; (4) Then, the mixed solution 4 was gradually added to the mixed solution 3 to obtain a mixed solution 5, and the mixed solution 5 was subjected to ultrasonic treatment for 2 hours after being stirred for 30 minutes; (5) Then, the obtained mixed solution 5 is evenly dropped onto a clean glass sheet; (6) then subjecting the mixed solution 5 on the glass sheet to thermal imidization treatment; (7) After the thermal imidization is completed, the mixed solution 5 forms a film on the glass sheet, the glass sheet is immersed in deionized water, and the film is peeled off from the glass sheet; (8) The film is dried in a vacuum oven to completely remove residual moisture to obtain a film.

2. A high temperature resistant polyimide dielectric film and a preparation method thereof according to claim 1, characterized in that: The dianhydride is one or more of 4,4'-oxydiphthalic anhydride, 4,4'-(hexafluoroisopropylene) diphthalic anhydride, bisphenol A type diether dianhydride, pyromellitic acid dianhydride, trans-hydrogenated anhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, and 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride; the diamine is one or more of 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 2,2'-bis(trifluoromethyl)-4,4'-diaminophenyl ether, 4,4'-[1,4-phenylbis(oxy)]bis[3-(trifluoromethyl)aniline], 1,3-bis(4'-aminophenoxy)benzene, and 2,2-bis[4-(4-aminophenoxy)phenyl]propane.

3. A high temperature resistant polyimide dielectric film and a preparation method thereof according to claim 1, characterized in that: In step (1), the solvent 1, solvent 2 and solvent 3 are one of N-methylpyrrolidone, dimethylformamide, dimethylacetamide and dimethyl sulfoxide.

4. A high temperature resistant polyimide dielectric film and a preparation method thereof according to claim 1, characterized in that: The molar ratio of the dianhydride to the diamine monomer is 1:

1.

5. A high temperature resistant polyimide dielectric film and a preparation method thereof according to claim 1, characterized in that: The organic semiconductor is one or more of perfluorohexacyanonaphthoquinone with a high electron affinity of 5.37 eV, tetrafluoro-7,7,8,8-tetracyanoquinodimethylene with a high electron affinity of 5.24 eV, and difluoro-7,7,8,8-tetracyanoquinodimethylene with a high electron affinity of 4.59 eV.

6. A high temperature resistant polyimide dielectric film and a preparation method thereof according to claim 1, characterized in that: The solid content of the organic semiconductor in the mixed solution 4 is 30-80%, and the amount of the mixed solution 4 added is 0.1-1.0% by volume of the mixed solution 3.

7. A high temperature resistant polyimide dielectric film and a preparation method thereof according to claim 1, characterized in that: The thermal imidization treatment process is: first drying at 80° C. for 12 hours to completely remove the solvent; then heating at 150° C., 200° C. and 250° C. for 1 hour each to ensure that the polymer is fully imidized.

8. A high temperature resistant polyimide dielectric film and a preparation method thereof according to claim 1, characterized in that: The film thickness is controlled between 10-12 um.

9. A high temperature resistant polyimide dielectric film and a preparation method thereof according to claim 1, characterized in that: The dianhydride and diamine were both from TCI Corporation of Japan, the organic semiconductor was from 1-Material Company of Canada, and the solvent was from Sigma Company.

10. A high temperature resistant polyimide dielectric film obtained according to the preparation method of claim 1.

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