All-organic PF / PC composite dielectric film containing molecular semiconductor and preparation method and application of all-organic PF / PC composite dielectric film

Abstract

The invention discloses a preparation method of an all-organic PF / PC composite dielectric film containing a molecular semiconductor. Belongs to the technical field of energy storage materials. The invention aims to improve the breakdown strength of the polymer medium and enhance the energy storage density of the polymer medium. According to the invention, PC particles and PF are dissolved in tetrahydrofuran to prepare a mixed solution, the PF / PC dielectric film is prepared by a method of drying after film coating, and the specific mechanism is that introduction of a molecular semiconductor PF forms a molecular trap with PC to inhibit transport of carriers, and hydrogen bonds are formed between fluorine atoms of PF and hydrogen atoms of PC to effectively inhibit migration of charge carriers, so that the performance of the PF / PC dielectric film is improved, and the performance of the PF / PC dielectric film is improved. Therefore, the insulating property of the polymer dielectric material is enhanced by inhibiting conduction, and the breakdown strength is finally improved. The invention can be widely applied to modern electronic equipment, 5G communication, electric automobiles, electromagnetic weapons and power systems.

Description

Technical Field

[0001] This invention belongs to the field of energy storage materials technology, specifically, it relates to an all-organic PF / PC composite dielectric thin film containing molecular semiconductors, its preparation method and application. Background Technology

[0002] The high-temperature performance of polymer capacitors plays a crucial role in the development of advanced electrical systems, especially in applications such as new energy vehicles, power electronic conversion devices, aerospace, and oil and gas exploration, where long-term service temperatures can reach 150 °C or even higher. Capacitors often become key components limiting system reliability and power density. However, at high temperatures, the number of thermally excited charge carriers within the polymer dielectric increases significantly, and the carrier mobility also increases markedly, leading to increased leakage current and exacerbated conductivity losses. Simultaneously, the dielectric constant and breakdown strength generally decrease with increasing temperature, reducing the available energy storage electric field strength and consequently causing a significant drop in energy storage density and charge / discharge efficiency. Failure to effectively suppress carrier transport and dielectric performance degradation under high-temperature conditions will severely restrict the application and promotion of polymer capacitors in high-temperature, high-power-density electrical systems. To improve the energy storage density of polymer dielectrics, researchers have conducted extensive studies, such as introducing inorganic high-dielectric-constant fillers to form high-dielectric polymer composites and preparing multilayer structures. However, there is still considerable room for improvement in the above strategies: on the one hand, inorganic fillers tend to agglomerate in polymers, making it difficult to achieve uniform dispersion. Interface defects and local electric field distortions not only weaken the dielectric enhancement effect but may also induce premature breakdown of the composite medium. On the other hand, multilayer structures usually require complex preparation processes and strict interlayer thicknesses, which are not conducive to large-area, low-cost industrial preparation. Summary of the Invention

[0003] The purpose of this invention is to improve the breakdown strength and energy density of polymer media by providing a method for preparing and applying an all-organic PF / PC composite dielectric film containing a molecular semiconductor. This invention introduces the molecular semiconductor 4,5,7,8,12,13,15,16-octafluoro[2.2] into polycarbonate (PC) to construct a molecular trap. Simultaneously, hydrogen bonds are formed between the PF and PC. These two elements synergistically inhibit carrier transport and migration in the PF / PC composite medium, enhancing the breakdown strength and thus improving the energy density of the composite medium.

[0004] To address the aforementioned technical problems, the present invention adopts the following technical solution: The purpose of this invention is to provide a method for preparing an all-organic PF / PC composite dielectric film containing a molecular semiconductor, which is carried out according to the following steps: polycarbonate (PC) particles and molecular semiconductor 4,5,7,8,12,13,15,16-octafluoro[2.2]-p-cycloarane (PF) are added to tetrahydrofuran (THF), stirred until completely dissolved, allowed to stand to remove bubbles, coated onto a pretreated substrate, the substrate is placed in a high-temperature drying oven to evaporate the solvent, then placed in a vacuum drying oven to keep warm, taken out, cooled to room temperature, and the film on the substrate is peeled off to obtain the PF / PC composite dielectric film.

[0005] Further specified, 4,5,7,8,12,13,15,16-octafluoro[2.2]-p-cycloarane (PF) accounts for 0.5%-2% of the mass of polycarbonate (PC) particles, which can be 0.5%, 1%, 1.5% and 2%.

[0006] Further specifying, the ratio of PC particle mass to tetrahydrofuran volume is (1.75~1.85) g : (10-12) mL.

[0007] Further specified, a magnetic stirrer is used for stirring, and the magnetic stirring speed is controlled at 300 r / min to 400 r / min.

[0008] Furthermore, the substrate is a glass plate.

[0009] Further specifying, the pretreatment of the substrate is carried out according to the following steps: first, wash with clean water 3 to 5 times, then rinse with deionized water 3 to 5 times, then wash with anhydrous ethanol 3 to 5 times, and finally dry at 75℃ to 80℃ for 11h to 12h.

[0010] Furthermore, the settling time is limited to 10-12 hours to allow all air bubbles in the solution to be expelled.

[0011] Further specify the process: first, keep the temperature at 60-70 ℃ until the solvent completely evaporates (high temperature drying oven) for about 10 hours, and then keep the temperature at 80-90 ℃ (vacuum drying oven) for about 8 hours.

[0012] Further, the thickness of the prepared PF / PC composite dielectric film is 4 μm to 6 μm.

[0013] Another object of the present invention is to provide an all-organic PF / PC composite dielectric film containing molecular semiconductors prepared by any of the above methods.

[0014] In addition, applications of the PF / PC composite dielectric film prepared by any of the above methods are provided, specifically in high-temperature polymer capacitors.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for preparing an all-organic PF / PC composite dielectric film containing a molecular semiconductor. The method involves dissolving PC particles and PF in tetrahydrofuran to form a mixed solution, coating the solution, and then drying the film. The specific mechanism is that the introduction of the molecular semiconductor PF forms molecular traps with PC, inhibiting carrier transport. Simultaneously, hydrogen bonds form between the fluorine atoms of PF and the hydrogen atoms of PC, effectively suppressing charge carrier migration. This inhibits conductivity, thereby enhancing the insulating properties of the polymer dielectric material and ultimately improving the breakdown strength. The synergistic effect of these two factors enhances the breakdown strength, thus increasing the energy density of the composite film.

[0016] This invention provides a method for preparing PF / PC composite dielectric films containing molecular semiconductors. The mass fraction of the molecular semiconductor PF is varied to 0.5%, 1%, 1.5%, and 2%. This invention exhibits excellent dielectric properties, breakdown performance, and energy storage performance, providing a new material for high-temperature capacitors. It can be widely applied in modern electronic devices, 5G communications, electric vehicles, electromagnetic weapons, and power systems. The preparation equipment and process of this invention are simple, easy to implement, low-cost, and environmentally friendly, providing an excellent strategy for developing advanced high-temperature polymer capacitors.

[0017] For a deeper understanding of the features and technical content of this invention, please refer to the accompanying detailed description and drawings. It should be noted that the drawings are provided for illustrative purposes only and are not intended to limit the scope of the invention. Attached Figure Description

[0018] Figure 1 Fourier transform infrared (FTIR) images of (0.5-2) wt% PF / PC composite dielectric films of Examples 1-4 and pure PC dielectric films of the comparative examples; Figure 2 The figures show scanning electron microscope (SEM) images of PF, pure PC, and PF / PC composite dielectric films with different PF mass fractions. Figure (a) shows the SEM image of PF; Figure (b) shows the SEM image of the pure polycarbonate (PC) film of Comparative Example 1; Figure (c) shows the SEM image of a cross-section of the 0.5 wt% PF / PC composite dielectric film of Example 1; Figure (d) shows the SEM image of a cross-section of the 1 wt% PF / PC composite dielectric film of Example 2; Figure (e) shows the SEM image of a cross-section of the 1.5 wt% PF / PC composite dielectric film of Example 3; and Figure (f) shows the SEM image of a cross-section of the 2 wt% PF / PC composite dielectric film of Example 4. Figure 3Glass transition temperature diagrams for (0.5-2) wt% PF / PC composite dielectric films of Examples 1-4 and pure PC dielectric films of the comparative examples; Figure 4 Figure 1 shows the dielectric constant and dielectric loss of PF / PC composite dielectric films at different temperatures as a function of frequency. Figure 2(a) shows the dielectric constant and dielectric loss of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 25 ℃ as a function of frequency. Figure 3(b) shows the dielectric constant and dielectric loss of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 100 ℃ as a function of frequency. Figure 4(c) shows the dielectric constant and dielectric loss of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 150 ℃ as a function of frequency.

[0019] Figure 5 Figure 1 shows the Weibull distribution of the breakdown field strength of PF / PC composite dielectric films at different temperatures. Figure 2(a) shows the breakdown field strength of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 25 ℃. Figure 3(b) shows the breakdown field strength of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 100 ℃. Figure 4(c) shows the breakdown field strength of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 150 ℃. Figure 6 Figure 1 shows the energy storage density and energy storage efficiency of PF / PC composite dielectric films at different temperatures. Figure 2(a) shows the energy storage density and energy storage efficiency of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 25 ℃. Figure 3(b) shows the energy storage density and energy storage efficiency of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 100 ℃. Figure 4(c) shows the energy storage density and energy storage efficiency of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 150 ℃. Figure 7Figure 1 shows the current density of PF / PC composite dielectric films at different temperatures. Figure 2(a) shows the current density of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 25 °C. Figure 3(b) shows the current density of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 100 °C. Figure 4(c) shows the current density of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 150 °C. Figure 8 Figure 1 shows the hysteresis loops of PF / PC composite dielectric films at different temperatures. Figure 2(a) shows the hysteresis loops of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 25 °C. Figure 3(b) shows the hysteresis loops of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 100 °C. Figure 4(c) shows the hysteresis loops of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 150 °C. Figure 9 Figure 1 shows the stress-strain curves of PF / PC composite dielectric films at different temperatures. Figure 2(a) shows the stress-strain curves of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 25 ℃. Figure 3(b) shows the stress-strain curves of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 100 ℃. Figure 4(c) shows the stress-strain curves of (0.5~2) wt% PF / PC composite dielectric films of Examples 1~4 and the pure PC dielectric film of the comparative example at 150 ℃. Figure 10 Analysis of intermolecular interactions between PF and PC based on IMH; Figure 11 This is the electrostatic potential distribution diagram of PF. Detailed Implementation

[0020] The present invention will be described in detail below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but should not be considered as limiting the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0021] Example 1: A method for preparing an all-organic PF / PC composite dielectric thin film containing molecular semiconductors, comprising the following steps: Step 1: Add 1.8g of polycarbonate (PC) particles and 9.045mg of molecular semiconductor 4,5,7,8,12,13,15,16-octafluoro[2.2]-p-cycloarane (PF) to 10mL of tetrahydrofuran (THF) to obtain a PF / PC mixture.

[0022] Step 2: Place the PF / PC mixture on a magnetic stirrer and stir at 400 r / min. Wait until the PC particles and PF powder are completely dissolved and the mixed solution is clear and transparent, then remove it from the magnetic stirrer and let it stand for 12 hours to allow all air bubbles in the solution to be expelled.

[0023] Step 3: Apply the bubble-free PF / PC mixed solution evenly onto the pretreated glass plate using a scraping tool.

[0024] The pretreatment of the glass plate is as follows: first, wash the glass plate with clean water 3 times, then rinse it with deionized water 3 times, then wash it with anhydrous ethanol 3 times, and finally dry it at 80 ℃ for 12 h.

[0025] Step 4: After coating, transfer the glass substrate to a high-temperature drying oven and keep it at 60 ℃ for 10 h to allow the solvent to evaporate completely. Then transfer it to a vacuum drying oven and keep it at 80 ℃ for 8 h. After the heat treatment is completed, cool it to room temperature, and finally peel off the film on the substrate to obtain a PF / PC composite dielectric film with a thickness of 5 μm.

[0026] In this embodiment, the molecular semiconductor 4,5,7,8,12,13,15,16-octafluoro[2.2] accounts for 0.5% of the total mass of polycarbonate (PC) particles and molecular semiconductor PF.

[0027] Example 2: This example differs from the previous one in that the medium molecular semiconductor 4,5,7,8,12,13,15,16-octafluoro[2.2]-p-cycloarane (PF for short) accounts for 1% of the total mass of the polycarbonate (PC) particles and the molecular semiconductor PF. Other steps and parameters are the same as in Example 1.

[0028] Example 3: In this example, the molecular semiconductor 4,5,7,8,12,13,15,16-octafluoro[2.2]-p-cycloarane (PF) accounts for 1.5% of the total mass of polycarbonate (PC) particles and molecular semiconductor PF. Other steps and parameters are the same as in Example 1.

[0029] Example 4: In this example, the molecular semiconductor 4,5,7,8,12,13,15,16-octafluoro[2.2]-p-cycloarane (PF) accounts for 2% of the total mass of polycarbonate (PC) particles and molecular semiconductor PF. Other steps and parameters are the same as in Example 1.

[0030] Comparative Example 1: Preparation of pure polycarbonate (PC) film; Step 1: Take 1.8 g of polycarbonate (PC) particles and add them to 10 ml of tetrahydrofuran solution. Stir mechanically at 30 °C for 10 h to obtain a polycarbonate (PC) solution. Adjust the height of the squeegee and use a squeegee coating method to coat the PC solution onto the substrate.

[0031] Step 2: Place the coated substrate in a 60 ℃ forced-air oven for 10 h; transfer the heated substrate to a vacuum oven and continue to keep it at 80 ℃ under vacuum for 10 h to remove air bubbles; remove the substrate and peel off the film with deionized water to obtain a pure polycarbonate film.

[0032] Figure 1 Fourier transform infrared (FTIR) images of PF / PC composite dielectric films with pure PC and different PF mass fractions are shown. Due to... Figure 1 (a) It can be seen that: the composite dielectric thin film at 1771 cm⁻¹ -1 It exhibits a characteristic absorption peak (C=O tensile vibration of PC) at 2971 cm⁻¹. -1 (CH stretching vibration), 1220 cm -1 (COC stretching vibration). Since the infrared spectrum did not show any new absorption peaks, this indicates that PF doping does not change the inherent chemical bonding structure of the PC matrix. Figure 1 (b) shows the change in the CH tensile vibration peak. When PF is mixed with PC, the CH tensile vibration peak changes from 2971 cm⁻¹. -1 Shifted to 2969 cm -1 This phenomenon can be attributed to the formation of intermolecular hydrogen bonds between PF and PC molecules. The hydrogen bond interaction elongates the CH bond, thereby lowering its vibrational frequency and causing the absorption peak to shift to a lower wavenumber.

[0033] Figure 2 Scanning electron microscope images of PF, pure PC, and PF / PC composite dielectric films with different PF mass fractions are shown. Due to... Figure 2 These images show that the film thickness is approximately 4-6 μm. SEM analysis of the cross-sectional microstructure reveals a highly dense and smooth morphology, with no observable pores, cracks, or other structural defects. This defect-free architecture indicates excellent process control during film fabrication.

[0034] Figure 3 Glass transition temperature diagrams are shown for the (0.5-2) wt% PF / PC composite dielectric films of Examples 1-4 and the pure PC dielectric film of the comparative example. Because... Figure 3 It can be seen that as the PF content increases, the glass transition temperature of the PF / PC polymer dielectric film (…)T g The initial value first decreased and then increased. At low PF content (<0.5 wt%), the initial... T g The decrease is attributed to conformational changes in the molecular chain caused by the incorporation of PF molecules. Subsequently, at higher PF contents (>1 wt%)... T g The increase is attributed to the enhanced intermolecular forces resulting from the high electronegativity of fluorine, which reduces free volume through stronger dipole-dipole and dispersive interactions. Notably, all composite materials exhibit... T g The values ​​are all lower than those of pure PC. T g The value (176.982℃) indicates that PF doping reduces the system's temperature. T g .

[0035] Figure 4 The graphs show the changes in dielectric constant and dielectric loss of PF / PC composite dielectric films as a function of frequency at different temperatures. Figure 4 It can be seen that at 25 °C, the dielectric constant of all dielectric thin films decreases with increasing frequency, which is attributed to the relaxation phenomenon of the dielectric. At 10 °C... -1 ~10 6 In the frequency range of Hz, the dielectric loss initially decreases with frequency and then increases with frequency. This is likely because dipoles can fully respond to changes in the electric field at low frequencies, while exhibiting a delayed polarization response at high frequencies. The dielectric constant of pure PC at 25 °C is approximately 3.1, showing a slight decreasing trend when the temperature rises to 100 °C and 150 °C. This is because the enhanced molecular thermal motion at high temperatures hinders the alignment of polar groups with the applied electric field, thus reducing overall polarization. The dielectric loss tangent (tan...) δ The dielectric constant increases significantly with increasing temperature, due to the increased charge carrier mobility at high temperatures, which leads to increased conduction losses. At 150 °C, the dielectric constant of pure PC film is 3.05, while that of 1 wt% PF / PC composite film reaches 3.12. The dielectric losses of both pure PC and PF / PC composite films are below 0.01, indicating that the excellent loss characteristics of the film originate from the strong electron-withdrawing ability of the highly insulating PF. This characteristic limits intrafilm transport after charge injection, effectively reducing dielectric loss.

[0036] Figure 5 This shows the Weibull distribution of the breakdown field strength of PF / PC composite dielectric films at different temperatures. Because... Figure 5It can be observed that the breakdown strength of the composite dielectric film initially increases and then decreases with increasing PF doping content. At 25 °C, the 1 wt% PF / PC composite dielectric film exhibits the highest breakdown strength (680 kV / mm), a 17% improvement compared to pure PC (581 kV / mm). At 100 °C, the 1 wt% PF / PC composite dielectric film exhibits the highest breakdown strength (628 kV / mm). At 150 °C, the 1 wt% PF / PC composite dielectric film exhibits the highest breakdown strength (550 kV / mm). The initial increase in breakdown strength can be attributed to the wide bandgap characteristics of PF and the synergistic effect of hydrogen bonding interactions between PF and PC. These combined mechanisms effectively suppress charge carrier migration, thereby enhancing the insulation properties of the polymer dielectric material by suppressing conductivity, and ultimately improving the breakdown strength. When the PF loading concentration is too high, the positively charged benzene ring structure may form local electron transport channels, accelerating breakdown and reducing the overall breakdown strength.

[0037] Figure 6 The graph shows the energy storage density and energy storage efficiency of PF / PC composite dielectric films at different temperatures. Because... Figure 6 It can be seen that at 25 ℃ and an electric field strength of 680 kV / mm, the energy storage density of a 1wt% PF / PC composite dielectric film reaches 6.43 J / cm². 3 Compared to pure PC (4.64 J / cm³), 3 The energy density was increased by 38.5%. At 100 °C and 150 °C, the energy storage density of the 1 wt% PF / PC composite dielectric film reached 5.31 J / cm³. 3 and 4.02 J / cm 3 Compared to pure PC (3.97 J / cm³), 3 100 ℃; 2.38 J / cm 3 The energy storage efficiency was increased by 33.8% and 68.9% respectively (at 150 °C). At room temperature, the charge / discharge efficiency of the composite material exceeded 90%, surpassing the 89.4% of pure PC. These results indicate that PF effectively suppresses carrier transport in the polymer dielectric and reduces leakage current density under high temperature and high electric field conditions. Therefore, the PF / PC composite dielectric film exhibits high energy storage efficiency and stable performance under high temperature conditions.

[0038] Figure 7 This shows the current density graphs of PF / PC composite dielectric films at different temperatures. Because... Figure 7It can be seen that, under the three test temperatures, the leakage current density of the composite dielectric film first decreases and then increases with the increase of PF content. Under the three test temperatures, the 1wt% PF / PC composite dielectric film exhibits the lowest leakage current density, while pure PC shows the highest value. At 150 ℃, pure PC has the highest leakage current density, reaching 2.35 × 10⁻⁶. -10 A / cm 2 The 1wt% PF / PC has the lowest leakage current density, at 1.86 × 10⁻⁶. -10 A / cm 2 When the PF loading concentration in the matrix is ​​low, introducing PF into the PC matrix can create a higher energy barrier, which suppresses carrier injection and hinders charge migration. When the PF loading concentration in the matrix is ​​high, the conjugated π-electron system associated with the PF benzene ring structure, where electron delocalization promotes carrier transport and increases conductivity. At different temperatures, the leakage current density of the same composite dielectric film increases with increasing temperature. This behavior is attributed to thermal excitation: increased temperature increases the probability of carrier migration by increasing the concentration and mobility of free carriers, thereby exacerbating the leakage current.

[0039] Figure 8 The diagram shows the hysteresis loops of PF / PC composite dielectric films at different temperatures. Because... Figure 8 It can be seen that at 25 °C, the composite dielectric film exhibits a slender hysteresis loop, indicating low energy loss. However, as the temperature increases to 100 °C and 150 °C, the loop widens significantly, indicating substantial energy dissipation under high temperature and high field conditions.

[0040] Figure 9 This shows the stress-strain curves of PF / PC composite dielectric films at different temperatures. Because... Figure 9 It can be seen that the tensile stress decreases with increasing temperature. This can be attributed to the enhanced thermal motion of the molecular chains at high temperatures, which promotes chain segment migration and chain slippage, thereby facilitating the release of internal residual stress and reducing the overall tensile strength. Compared with pure PC, the incorporation of the molecular semiconductor PF does not negatively affect the mechanical properties of the composite dielectric film.

[0041] Figure 10 This study focuses on the analysis of intermolecular interactions between PF and PC molecules based on IGMH. Because... Figure 10 Theoretical calculations and simulations reveal intermolecular interactions between PF and PC. Independent gradient model (IGMH) analysis reveals significant non-covalent interactions between PF and PC. The blue isosurfaces indicate hydrogen bonds (HF) formed between the fluorine atoms of PF and the aromatic CH groups in the PC backbone, while the green regions correspond to the contributions of van der Waals interactions.

[0042] Figure 11This is the electrostatic potential distribution diagram of PF. Because... Figure 11 It can be seen that the red region corresponding to the negative electrostatic potential is mainly located around the fluorine atoms. This distribution stems from the strong electron-withdrawing property of fluorine, which polarizes the electron density of the benzene ring towards itself. As shown in the blue region, this electron redistribution results in the main positive electrostatic potential in the molecule, indicating that PF has a significant electron affinity.

[0043] The specific embodiments of the present invention have been described in detail above. It should be noted that the present invention is not limited to the specific embodiments described above. Various modifications or alterations can be made by those skilled in the art without departing from the scope of protection defined by the claims, and all such modifications or alterations fall within the scope of the present invention.

Claims

1. A method for preparing a full-organic PF / PC composite medium thin film containing molecular semiconductors, characterized in that, The method comprises the following steps: Polycarbonate (PC) particles and molecular semiconductor 4,5,7,8,12,13,15,16-octahydro[2.2]p-para-cyclofluorine (PF) are added to tetrahydrofuran (THF), stirred until completely dissolved, deaerated, coated on a pretreated substrate, then placed in a high-temperature drying oven to evaporate the solvent, then placed in a vacuum drying oven, taken out, cooled to room temperature, then the film on the substrate is peeled off, and the PF / PC composite medium film is obtained.

2. The method of claim 1, wherein, The PF accounts for 0.5%-2% of the mass of the PC.

3. The method of claim 1, wherein, The ratio of the mass of the PC particles to the volume of tetrahydrofuran is (1.75-1.85) g:(10-12) mL.

4. The method of claim 1, wherein, Magnetic stirring is adopted, and the stirring speed is 300-400 r / min.

5. The method of claim 1, wherein, The substrate is a glass plate.

6. The method of claim 1, wherein, Substrate pretreatment: first washed with clean water for 3-5 times, then washed with deionized water for 3-5 times, then washed with anhydrous ethanol for 3-5 times, and finally dried at 75-80 ℃ for 11-12 h.

7. The method of claim 1, wherein, First, heat to 60-70 ℃ until the solvent is completely evaporated, and then heat to 80-90 ℃.

8. The method of claim 1, wherein, The thickness of the PF / PC composite medium film is 4-6 μm.

9. A molecular semiconductor-containing all-organic PF / PC composite medium film prepared by the method of any one of claims 1-8.

10. Use of a PF / PC composite dielectric film prepared according to the method of any one of claims 1 to 8, characterized in that The molecular semiconductor-containing all-organic PF / PC composite medium film is applied to a high-temperature-resistant polymer capacitor.

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