Hole transport layer molecule with thermally activated delayed fluorescence characteristic and preparation method and application thereof

Abstract

The invention discloses a hole transport layer molecule with a thermally activated delayed fluorescence characteristic, a preparation method thereof and an application of the hole transport layer molecule in a solar cell. The hole transport layer molecule integrates efficient hole transport capability and unique thermally activated delayed fluorescence characteristics through ingenious donor-receptor structural design, and creates a remarkable synergistic enhancement effect. Compared with a traditional material, the core advantage is that the device filling factor and efficiency are significantly improved. The inherent front line orbit space separation characteristic of molecules ensures high hole mobility, and the series resistance of the device is effectively reduced; meanwhile, the TADF effect can construct an efficient'exciton recovery 'mechanism at a perovskite / transmission layer interface, non-radiation loss triplet excitons are converted into reusable photons, interface recombination is greatly inhibited, and thus FF and photoelectric conversion efficiency breakthrough are jointly driven.

Description

Technical Field

[0001] This invention relates to the field of organic optoelectronic materials and devices, specifically to a novel hole transport layer (HTL) molecule, namely a hole transport layer molecule with thermally activated delayed fluorescence (TADF) properties, as well as the preparation method of the molecule and its application in solar cells, aiming to effectively improve the fill factor and final photoelectric conversion efficiency of the cell through the unique TADF properties of the molecule. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Perovskite solar cells (PSCs) have become one of the most promising competitors in the next generation of photovoltaic technology due to their high efficiency and low cost. Their certified power conversion efficiency (PCE) has exceeded 26%, approaching the level of monocrystalline silicon cells. PCE is determined by the open-circuit voltage (…). V OC ), short-circuit current density ( J SC The composition of the material is determined by three key parameters: component composition, fill factor (FF), and other parameters. Currently, the research community is using methods such as component engineering and interface modification to improve the composition of the material. V OC and J SC Significant progress has been made in this area; however, the improvement potential of charge collection (FF), a key indicator for measuring the completeness of charge collection within a device, is gradually becoming a bottleneck restricting further breakthroughs in PCE.

[0004] The fill factor directly reflects the "squareness" of the solar cell's output characteristic curve, and its level is mainly determined by the series and parallel resistances of the device. In perovskite cells, the fill factor (FF) loss mainly originates from: (1) Mismatch between interface charge extraction and transport dynamics: Traditional hole transport materials (such as Spiro-OMeTAD, PTAA) have limited charge mobility and usually require the addition of dopants such as lithium salts to improve conductivity. These dopants not only introduce water-absorbing impurities and reduce the long-term stability of the device, but may also cause non-radiative recombination of charges at the interface between the transport layer and the perovskite or in the transport layer itself, increasing the series resistance and thus directly leading to a decrease in FF.

[0005] (2) Interface energy loss: The energy level mismatch between the perovskite absorber layer and the hole transport layer will form an interface energy barrier, which will hinder the efficient and rapid extraction of holes. This extraction delay increases the probability of carrier recombination at the interface, which is also manifested as a loss of FF.

[0006] In recent years, self-assembled monolayers (SAMs), such as Me-4PACz and 2PACz, have shown promise as hole transport layers due to their extremely thin thickness, excellent energy level tuning capabilities, and low material consumption, enabling the achievement of high flyback distances and high efficiency. V OC The immense potential of SAM materials. However, while pursuing energy level matching, the intrinsic electrical properties of existing SAM materials, especially excited-state properties, have not been fully explored and utilized.

[0007] TADF materials are the core of third-generation organic light-emitting materials, which utilize the extremely small energy level difference (ΔE) between the lowest singlet excited state (S1) and the lowest triplet excited state (T1). ST This technology can utilize ambient thermal energy to reverse the intersystem flow of triplet excitons, which are normally unusable for luminescence, to the singlet state, thereby achieving nearly 100% exciton utilization. If this unique "exciton recovery" mechanism can be cleverly introduced into the charge transport layer of photovoltaic devices, it is expected to provide a completely new approach to solving the interfacial recombination problem.

[0008] Introducing TADF characteristics into the hole transport layer is expected to improve the FF of perovskite solar cells through the following synergistic mechanism: First, TADF molecules typically have a frontier orbital (HOMO / LUMO) spatially separated electron donor-acceptor (DA) structure, which not only enables efficient TADF luminescence but also facilitates the localization and directional transport of holes on the donor unit, potentially leading to higher intrinsic hole mobility and reduced series resistance.

[0009] Secondly, and most importantly, when the TADF-type hole transport layer comes into contact with the perovskite layer, a highly efficient "exciton buffer and recycling platform" is formed at the interface. Low-energy triplet excitons generated in the perovskite, which may be trapped, or charge-transfer states formed at the interface, can transfer energy to the TADF molecules via energy transfer. After absorbing energy, the TADF molecules re-emit the energy as photons through their rapid thermally activated delayed fluorescence process. These re-emitted photons can be reabsorbed by the perovskite, thus indirectly "recovering" excitons that might otherwise be lost through nonradiative recombination. This process effectively reduces nonradiative recombination losses at the interface, significantly increases the device's parallel resistance, and thus makes a significant improvement in FF (field-effect) possible.

[0010] Currently, research on designing molecules with well-defined TADF properties and applying them to the hole transport layer of perovskite solar cells to specifically address the flyback-free (FF) bottleneck is still lacking. Existing hole transport material design approaches mostly focus on energy level matching and mobility enhancement, neglecting to utilize their excited-state properties to actively manage interfacial exciton behavior. Therefore, developing a novel molecule that combines highly efficient hole transport capabilities with unique TADF properties, suppressing interfacial recombination through an "exciton recovery" mechanism, specifically for overcoming the FF limit of perovskite solar cells, has extremely important scientific significance and enormous application value. Summary of the Invention

[0011] To address the aforementioned technical problems and shortcomings in the field, this invention provides a hole transport layer molecule with thermally activated delayed fluorescence properties, its preparation method, and its applications.

[0012] The specific technical solution is as follows: In a first aspect, the present invention provides an organic non-fullerene small molecule having the following structure: R1-R4 are each independently an alkyl group with 1 to 30 carbon atoms (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, etc.), wherein the alkyl group is straight-chain or branched. For example, R1-R4 are all tert-butyl groups; n represents the number of methylene-CH2- groups, selected from 1 to 20, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, etc.

[0013] The organic non-fullerene small molecules possess thermally activated delayed fluorescence properties and can be used as hole transport layer molecules.

[0014] Secondly, the present invention provides the application of the organic non-fullerene small molecules described in the first aspect in solar cells. Further, the organic non-fullerene small molecules are used to prepare a hole transport layer.

[0015] The solar cell may include one or more of the following: perovskite solar cell, quantum dot solar cell, organic solar cell, etc.

[0016] Thirdly, the present invention provides the application of the organic non-fullerene small molecules described in the first aspect as hole transport layer molecules to improve the fill factor of solar cells. The solar cells may include one or more of perovskite solar cells, quantum dot solar cells, organic solar cells, etc.

[0017] Fourthly, the present invention provides a solar cell including a hole transport layer, the hole transport layer containing the organic non-fullerene small molecules described in the first aspect and / or made of the organic non-fullerene small molecules described in the first aspect.

[0018] The solar cell may be a perovskite solar cell, a quantum dot solar cell, or an organic solar cell, etc.

[0019] Fifthly, the present invention provides a method for preparing the organic non-fullerene small molecule described in the first aspect, using the following synthetic route: The preparation method includes the following steps: (a) In the presence of a palladium catalyst and a weak base, carbazole raw material I with a boron nitrogen structure undergoes a Suzuki coupling reaction with (9H-carbazole-4-yl)boronic acid II in a first solvent to generate intermediate III; (b) In the presence of a phase transfer catalyst and a strong base, intermediate III undergoes an alkylation reaction with excess dibromoalkane IV in a second solvent to generate a side-chain brominated intermediate V. (c) The side-chain brominated intermediate V is reacted with a phosphite via an Arbuzov reaction to give intermediate VI, wherein R5 and R6 are independently methyl or ethyl; (d) Intermediate VI was hydrolyzed in the reaction solvent with a silane reagent, and then purified by precipitation in an alcohol / water system to obtain the small organic non-fullerene molecule VII.

[0020] Furthermore, in step (a), the palladium catalyst comprises one or more of tetra(triphenylphosphine)palladium, [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride, and tris(dibenzylacetone)palladium.

[0021] Furthermore, in step (a), the weak base includes one or more of sodium carbonate, potassium carbonate, cesium carbonate, and potassium phosphate.

[0022] Furthermore, in step (a), the weak base is added in the form of an aqueous solution.

[0023] Furthermore, in step (a), the first solvent includes one or more of toluene, 1,4-dioxane, N,N-dimethylformamide, and tetrahydrofuran.

[0024] Furthermore, in step (a), the Suzuki coupling reaction temperature ranges from 70°C to 120°C.

[0025] Furthermore, in step (a), the Suzuki coupling reaction time is 2 to 24 hours.

[0026] Furthermore, in step (b), the phase transfer catalyst includes one or more of tetrabutylammonium bromide, tetrabutylammonium chloride, and tetrabutylammonium bisulfate.

[0027] Furthermore, in step (b), the strong base includes at least one of sodium hydroxide and potassium hydroxide.

[0028] Furthermore, in step (b), the strong alkali is added in the form of an aqueous solution.

[0029] Furthermore, in step (b), the second solvent includes one or more of tetrahydrofuran, acetone, and ethanol.

[0030] Furthermore, in step (b), the alkylation reaction temperature ranges from 50°C to 80°C.

[0031] Furthermore, in step (b), the alkylation reaction time is 1 to 36 hours.

[0032] In a preferred embodiment, in step (b), dibromoalkane II comprises 1,4-dibromobutane.

[0033] Furthermore, in step (c), the phosphite includes at least one of triethyl phosphite and trimethyl phosphite.

[0034] Furthermore, in step (c), the Arbuzov reaction is carried out under an inert gas atmosphere.

[0035] Furthermore, in step (c), the Arbuzov reaction temperature ranges from 120°C to 180°C.

[0036] Furthermore, in step (c), the Arbuzov reaction time is 12 to 48 hours.

[0037] Furthermore, in step (d), the silane reagent includes at least one of trimethylbromosilane and trimethylchlorosilane.

[0038] Furthermore, in step (d), the reaction solvent includes one or more of dichloromethane, tetrahydrofuran, and 1,4-dioxane.

[0039] Furthermore, in step (d), the hydrolysis reaction temperature is between -20°C and 30°C.

[0040] Furthermore, in step (d), the hydrolysis reaction time is 5 to 72 hours.

[0041] Furthermore, in step (d), the precipitation purification of the alcohol / water system specifically includes: dissolving the crude product from the hydrolysis reaction in chloroform and / or tetrahydrofuran, and then reprecipitating it in water.

[0042] Compared with the prior art, the beneficial effects of this invention are as follows: The hole transport layer molecule of this invention, through a clever donor-acceptor structure design, integrates highly efficient hole transport capability with unique thermally activated delayed fluorescence characteristics, creating a significant synergistic enhancement effect. Compared with traditional materials, its core advantage lies in significantly improving the device fill factor (FF) and efficiency. The inherent frontier orbital spatial separation characteristics of the molecule ensure high hole mobility, effectively reducing the device series resistance; simultaneously, its TADF effect can construct an efficient "exciton recovery" mechanism at the perovskite / transport layer interface, converting non-radiatively lost triplet excitons into reusable photons, greatly suppressing interface recombination, thereby jointly driving breakthroughs in FF and photoelectric conversion efficiency. Furthermore, this invention possesses excellent versatility and application prospects. This design strategy can be flexibly extended to a series of DA-type TADF molecules, providing a novel material platform and technical path for developing next-generation high-performance, high-stability perovskite optoelectronic devices. Attached Figure Description

[0043] Figure 1 This is a synthetic route diagram for BN-4PACz, a hole transport layer molecule with thermally activated delayed fluorescence properties, as shown in Example 1.

[0044] Figure 2 The 1H NMR spectrum of BN-4PACz, a hole transport layer molecule with thermally activated delayed fluorescence properties, as described in Example 1. 1 (H NMR) image.

[0045] Figure 3 The image shows the MALDI-TOF mass spectrum of BN-4PACz, a hole transport layer molecule with thermally activated delayed fluorescence properties, as described in Example 1.

[0046] Figure 4 This is the UV-Vis absorption spectrum of BN-4PACz, a hole transport layer molecule with thermally activated delayed fluorescence properties, as shown in Example 2.

[0047] Figure 5 This is the ultraviolet photoelectron spectrum of BN-4PACz, a hole transport layer molecule with thermally activated delayed fluorescence properties, as shown in Example 2.

[0048] Figure 6 This refers to the perovskite device with the thermally activated delayed fluorescence characteristic of the hole transport layer molecule BN-4PACz in Example 3. JV Line graph. Detailed Implementation

[0049] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Operating methods not specifically specified in the following embodiments are generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise specified, the materials, reagents, etc., used in the following embodiments are commercially available.

[0050] Example 1: The organic non-fullerene small molecule in this embodiment is a hole transport layer molecule, BN-4PACz, which has thermally activated delayed fluorescence properties and has the following structure: R1-R4 are all tert-butyl groups; n represents the number of methylene-CH2- groups, which is 4.

[0051] The preparation process of BN-4PACz is as follows: Figure 1 As shown, the specific steps are as follows: (a) Carbazole raw material 1 (0.58 g, 0.82 mmol) with a boron-nitrogen structure and (9H-carbazole-4-yl)boronic acid (0.21 g, 0.98 mmol) were added to a 100 mL Schlenk tube and dissolved in toluene (45 mL). Then, 50 wt% potassium carbonate aqueous solution (5 mL) was slowly added dropwise. The mixture was heated to 100 °C and stirred overnight. After the reaction was complete, the mixture was quenched with water and extracted with dichloromethane. The organic phases were combined, dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation to obtain the crude product. Finally, the crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane (5:1, v / v) as the eluent to give intermediate 2 (0.52 g, 79% yield), a colorless oily substance. (b) Intermediate 2 (0.52 g, 0.65 mmol) and tetrabutylammonium bromide (0.32 g, 0.27 mmol) were added to a 100 mL double-necked flask and dissolved in 1,4-dibromobutane (15 mL) and tetrahydrofuran (20 mL). Then, 50 wt% potassium hydroxide aqueous solution (5 mL) was slowly added dropwise. The mixture was heated to 65 °C and stirred overnight. After the reaction was complete, the mixture was quenched with water and extracted with dichloromethane. The organic phases were combined, dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation to obtain the crude product. Finally, the crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane (10:1, v / v) as the eluent to obtain intermediate 3 (0.49 g, 80% yield), a colorless oil.

[0052] (c) Add intermediate 3 (0.49 g, 0.52 mmol) and triethyl phosphite (10 mL) to a 100 mL Schlenk tube. Under nitrogen protection, heat the mixture to 160 °C and stir for 24 hours. After the reaction is complete, remove excess triethyl phosphite by vacuum distillation to obtain a pale yellow oily intermediate 4, which requires no further purification.

[0053] (d) Under nitrogen protection, the pale yellow oily intermediate 4 was dissolved in anhydrous 1,4-dioxane (10 mL), and trimethylbromosilane (3.66 g, 23.90 mmol) was slowly added dropwise in an ice bath. The mixture was then stirred in an ice bath overnight. After the reaction was complete, 1,4-dioxane was removed by rotary evaporation to obtain a white solid. The white solid was dissolved in methanol (10 mL), and deionized water was slowly added dropwise at room temperature until the mixture became turbid. Stirring was continued for 12 hours. The crude product was collected by filtration and washed with deionized water. The crude product was dissolved in tetrahydrofuran (5 mL), and then redeprecipitated in water (20 mL). After filtration, the final product was a white solid 5 (0.38 g, 78% yield).

[0054] Figure 2 BN-4PACz, a hole transport layer molecule with thermally activated delayed fluorescence properties. 1 1H NMR spectrum. Proton NMR data for BN-4PACz. 1 H NMR (400 MHz, CDCl3, ): 9.15 (d, J = 2.2 Hz, 2H), 8.64 (s,1H), 8.62 (d, J = 1.6 Hz, 2H), 8.53 (s, 1H), 8.51 (s, 1H), 8.48 (d, J = 1.6Hz, 2H), 8.29-8.27 (m, 3H), 8.08-8.05 (m, 1 H), 7.71-7.30 (m, 6H), 4.45-4.42(t, J = 8 Hz, 2H), 2.11-2.08 (t, J = 12 Hz, 2H), 1.84 (d, J = 8 Hz, 2H), 1.69 (s, 18H), 1.54 (s, 18H).

[0055] Figure 3This is the MALDI-TOF mass spectrum of BN-4PACz, a hole transport layer molecule with thermally activated delayed fluorescence properties. Mass spectrometry data of BN-4PACz (MALDI-TOF): Chemical formula C 62 H 65 BN3O3P [M+H] + The calculated value is 942.485, and we find 942.492.

[0056] Example 2: Solar absorption spectrum and redox potential test.

[0057] 1) Solar Absorption Spectroscopy Test: A Shimadzu UV-3600i Plus UV-Vis-NIR spectrometer was used to test the BN-2PACz solution (chloroform as solvent) and thin film in a dual-beam configuration. The light sources were a 50W halogen lamp and a gas lamp. The test results are as follows: Figure 4 As shown: The absorption cutoff edge of BN-2PACz in chloroform solution in Example 1 is 321 nm. Its optical band gap was calculated. E g) is 3.86 eV.

[0058] 2) Ultraviolet photoelectron spectroscopy (UVP) testing: The BN-4PACz thin film was tested using an Escalab Xi+ X-ray photoelectron spectroscopy platform. The test results are as follows: Figure 5 As shown: The HOMO level of BN-4PACz in Example 1 is calculated to be -5.26 eV, and the LUMO level is based on the above. E The calculated result for g is -1.40 eV.

[0059] Example 3: Device fabrication of perovskite solar cells: The ITO glass was washed with detergent, distilled water, acetone, and isopropanol, respectively, and the solvent was removed in an oven at 100°C. After O3 / UV treatment for 30 minutes, it was transferred to a glove box under nitrogen protection, and then a hole transport layer material (control molecule: Me-4PACz; target molecule: BN-4PACz from Example 1) was coated. After heat annealing at 100°C for 10 minutes, it was cooled to room temperature and then spin-coated with a perovskite solution with a concentration of approximately 1.5 M. The perovskite solution was prepared by dissolving 4 mg DMAcPA, 6.7 mg MABr (MA represents methylamine cation), 8.8 mg MACl, 18.2 mg CsI, 196.1 mg FAI (FA represents methylamine cation), 22 mg PbBr2, and 572 mg PbI2 in 865 mL of water. The active layer was obtained by mixing N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) in a volume ratio of 4:1. After solvent annealing, the passivation layer material phenylethyl ammonium bromide (PEABr), the transport layer material PCBM, and the interface layer material BCP were sequentially spin-coated. After thermal annealing at 100°C for 10 minutes, the active layer was transferred to an evaporation chamber to evaporate the Ag electrode to 100 nm.

[0060] Photovoltaic performance testing process: Under xenon lamp illumination, the device is tested for current density and voltage using a source meter and computer-configured software. J - V The curve was tested (results are shown in Table 1 and...). Figure 6 (As shown).

[0061] Results Analysis: To quantitatively evaluate the performance improvement of BN-4PACz on devices, comparative tests were conducted using the classic hole transport material Me-4PACz as a benchmark. Test results show that the open-circuit voltage of devices based on Me-4PACz (…) V OC The voltage is 1.17V, and the short-circuit current density is ( J SC The value is 25.29 mA cm. -2 The fill factor (FF) is 83.08%, and the final power conversion efficiency (PCE) is 24.58%; while the device based on BN-4PACz maintains the same performance. V OC (1.17 V) and slightly increased J SC (25.37 mA cm) -2 Based on the previous method, the fill factor (FF) was significantly improved to 85.29%, and the final PCE was increased to 25.31%. The conclusion is that BN-4PACz can significantly improve the device fill factor, thereby effectively enhancing its photoelectric conversion efficiency.

[0062] Table 1 shows the device performance parameters of the perovskite solar cell in Example 3.

[0063] Table 1 Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. An organic non-fullerene small molecule characterized in that, has the following structure: R1-R4 are independently alkyl of 1-30 carbons, which is linear or branched; n represents the number of methylene-CH2- and is selected from 1-20.

2. The application of the organic non-fullerene small molecule according to claim 1 in a solar cell.

3. Use according to claim 2, characterized in that, The solar cell includes one or more than two of a perovskite solar cell, a quantum dot solar cell, and an organic solar cell.

4. Use according to claim 2 or 3, characterized in that, The organic non-fullerene small molecule is used to prepare a hole transport layer.

5. The application of the organic non-fullerene small molecule according to claim 1 as a hole transport layer molecule to improve the fill factor of a solar cell.

6. A solar cell comprising a hole transporting layer, characterized in that, The hole transport layer contains the organic non-fullerene small molecule according to claim 1 and / or is prepared by the organic non-fullerene small molecule according to claim 1.

7. The solar cell according to claim 6, characterized in that, The solar cell is a perovskite solar cell, a quantum dot solar cell, or an organic solar cell.

8. The method of preparing an organic non-fullerene small molecule according to claim 1, wherein The following synthetic route is adopted: The preparation method includes the following steps: (a) in the presence of a palladium catalyst and a weak base, a Suzuki coupling reaction occurs between a carbazole raw material I with a boron-nitrogen structure and (9H-carbazol-4-yl)boronic acid II in a first solvent to generate an intermediate III; (b) in the presence of a phase transfer catalyst and a strong base, an alkylation reaction occurs between the intermediate III and an excess of a dibromoalkane IV in a second solvent to generate a side chain brominated intermediate V; (c) the side chain brominated intermediate V is subjected to an Arbuzov reaction with a phosphite to obtain an intermediate product VI, wherein R5 and R6 are independently methyl or ethyl; (d) the intermediate product VI is subjected to a silane reagent hydrolysis reaction in a reaction solvent, and then is precipitated and purified in an alcohol / water system to obtain the organic non-fullerene small molecule VII.

9. The production method according to claim 8, characterized by, In step (a): the palladium catalyst includes one or more than two of tetrakis(triphenylphosphine)palladium, [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium, and tris(dibenzylideneacetone)dipalladium; the weak base includes one or more than two of sodium carbonate, potassium carbonate, cesium carbonate, and potassium phosphate, which is added in the form of an aqueous solution; the first solvent includes one or more than two of toluene, 1,4-dioxane, N,N-dimethylformamide, and tetrahydrofuran; the Suzuki coupling reaction temperature ranges from 70°C to 120°C; and the Suzuki coupling reaction time is 2-24 hours; In step (b): the phase transfer catalyst includes one or more than two of tetrabutylammonium bromide, tetrabutylammonium chloride, and tetrabutylammonium hydrogen sulfate; the strong base includes at least one of sodium hydroxide and potassium hydroxide, which is added in the form of an aqueous solution; the second solvent includes one or more than two of tetrahydrofuran, acetone, and ethanol; the alkylation reaction temperature ranges from 50°C to 80°C; and the alkylation reaction time is 1-36 hours; In step (c): the phosphite includes at least one of triethyl phosphite and trimethyl phosphite; the Arbuzov reaction is carried out under inert gas protection; the Arbuzov reaction temperature ranges from 120°C to 180°C; and the Arbuzov reaction time is 12-48 hours; In step (d), the silane reagent includes at least one of trimethylbromosilane and trimethylchlorosilane; the reaction solvent includes one or more than two of dichloromethane, tetrahydrofuran and 1,4-dioxane; the hydrolysis reaction temperature is -20°C to 30°C; the hydrolysis reaction time is 5-72 hours; and the alcohol / water system precipitation purification specifically includes: dissolving the hydrolysis reaction crude product in dichloromethane and / or tetrahydrofuran, and re-precipitating in water.

10. The method of claim 8, wherein, In step (b), the dibromoalkane II includes 1,4-dibromobutane.

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