A fullerene C 60 Tetraaddition derivatives, their preparation methods and applications

Abstract

This invention discloses a fullerene C 60 Tetraaddition derivatives, their preparation methods, and applications. This fullerene C... 60 The tetraaddition derivative structure is shown in Formula I. The specific preparation method is as follows: under inert gas protection, using fullerene C 60 Using tetrabutylammonium hydroxide hydrate, benzyl bromide, and TBAOH methanol solution as raw materials, and o-dichlorobenzene or toluene as solvent, the reaction is carried out at 60–80 °C to obtain the target fullerene C. 60 Tetraaddition derivative. This fullerene C 60 The preparation method of the tetraaddition derivative has the advantages of simple operation steps, safety and easy control, and high selectivity. Photovoltaic devices fabricated using this fullerene derivative as an acceptor material exhibit high open-circuit voltage, making it a very promising photovoltaic material.

Description

Technical Field

[0001] This invention belongs to the field of fullerene derivatives, and specifically relates to a fullerene C 60 Tetraaddition derivatives, their preparation methods, and applications. These fullerene derivatives can be used as acceptor materials in the field of organic solar cells. Background Technology

[0002] Fullerenes, as hollow molecules composed entirely of carbon, possess a unique zero-dimensional structure and a conjugated π-electron system. Functionalizing the carbon skeleton of fullerenes by introducing various functional groups has become an important research direction in fullerene chemistry. Currently, numerous fullerene derivatives have been successfully synthesized and are widely used in materials science, drug development, electronic devices, and energy storage. These derivatives not only inherit the excellent properties of the fullerene family, such as excellent electron mobility and unique chemical reactivity, but also introduce new functions through chemical modification, such as enhanced solubility, improved biocompatibility, and specific spectral properties. Among them, monoaddition fullerenes C1... 60 Derivative [6,6]-phenyl-C 61 Methyl butyrate (PCBM), as an acceptor material, is blended with poly(3-hexylthiophene) (P3HT) as a donor material to construct organic solar cells (OSCs) photovoltaic devices. This effectively promotes the separation and transport of photogenerated charges and plays a key role in photovoltaic devices.

[0003] Fullerene C 60 Tetraaddition derivatives belong to a class of fullerene derivatives with special structures and properties. Compared to monoaddition fullerenes C... 60 These derivatives introduce four addition groups onto the four carbon atoms of the fullerene carbon cage, thus forming new compounds. These derivatives retain the C atoms of the fullerene. 60 The parent compound exhibits several superior properties, such as high electron mobility. Furthermore, compared to the monoaddition derivative PCBM, the tetraaddition derivative displays a higher LUMO (lowest unoccupied molecular orbital) energy level due to the reduced number of conjugated π electrons. This increased LUMO energy level helps improve the open-circuit voltage of photovoltaic devices, thereby enhancing the energy conversion efficiency of solar cells.

[0004] Fullerene C 60Tetraaddition derivatives of fullerenes can be prepared through various chemical reactions, such as the Prato reaction and the Bingel reaction. By introducing addition groups, the solubility, electronic properties, and energy level distribution of fullerenes can be adjusted to meet different application requirements. However, achieving regioselectivity control of tetraaddition products remains a challenge. The synthesis of these tetraaddition derivatives generally faces the following difficulties: complex operating procedures, harsh reaction conditions, the existence of multiple regioisomers in the resulting products, and difficulties in product separation and purification. Furthermore, when these regioisomer mixtures are used as acceptor materials in organic solar cells, their disordered accumulation leads to a reduction in the number of charge carriers reaching the electrode, thereby decreasing the charge extraction and transport efficiency within the cell. This phenomenon results in a decrease in short-circuit current density and fill factor, thus adversely affecting the performance of organic solar cells.

[0005] Therefore, it is necessary to develop a fullerene C with high selectivity and ease of operation. 60 The preparation method of tetraaddition derivatives is therefore crucial. By introducing appropriate modifying groups through this method, the selectivity of the reaction can be improved, which is beneficial for separation and purification, thereby obtaining pure and structurally singular fullerene C3. 60 Tetraaddition derivative. This fullerene C 60 Tetraaddition derivatives have higher LUMO energy levels, and as acceptor materials, they can effectively improve the open-circuit voltage of photovoltaic devices, which is expected to improve the photoelectric performance of organic solar cells. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a fullerene C 60 Tetraaddition derivatives, their preparation methods, and applications. The preparation method for this derivative has advantages such as simple operation steps, safety, easy control, and high selectivity. The fullerene C... 60 Organic solar cell devices constructed using tetraaddition derivatives as acceptor materials exhibit high open-circuit voltage and good photovoltaic performance.

[0007] To achieve the above objectives, a first aspect of the present invention is to provide a fullerene C 60 Tetraaddition derivative, with the molecular formula 1-CH3O-2,4,15-(C6H5CH2)3C 60 The fullerene C 60 The structural formula of the tetraaddition derivative is shown in Formula I.

[0008]

[0009] Formula I

[0010] A second aspect of the present invention is to provide the fullerene C said in this invention. 60 The preparation method of the tetraaddition derivative includes the following preparation steps:

[0011] Step 1: Under inert gas protection, add fullerene C to a round-bottom flask sequentially. 60 Organic solvent, tetrabutylammonium hydroxide hydrate, stirred and reacted at a certain temperature for 0.5 to 1 hour;

[0012] Step 2: Based on Step 1, add benzyl bromide to the round-bottom flask and react for 0.5 to 1 hour;

[0013] Step 3: Based on Step 2, continue to add TBAOH methanol solution to the round-bottom flask, react for 0.5 to 1 hour, after the reaction is complete, evaporate to remove the solvent, and then wash and dry to obtain the crude product;

[0014] Step 4: The crude product obtained in Step 3 is separated and purified by high performance liquid chromatography to obtain the target fullerene C. 60 Tetra-addition derivatives.

[0015] In the technical solution of this invention, the chemical reaction that occurs is shown in Formula II.

[0016]

[0017] Formula II

[0018] In the technical solution of this invention, step one: under the protection of an inert gas, fullerene C is added sequentially to a round-bottom flask. 60 An organic solvent and tetrabutylammonium hydroxide hydrate were added, and the mixture was stirred and reacted at a certain temperature for 0.5 to 1 hour. The addition of tetrabutylammonium hydroxide hydrate to the reaction facilitates the formation of C. 60 Negative ions increase fullerene C 60 Reactivity; Step 2: Based on Step 1, add benzyl bromide to the round-bottom flask and react for 0.5 to 1 hour. In this step, benzyl bromide acts as an electrophilic reagent, reacting with C... 60 The negative ions react; Step 3: Based on Step 2, TBAOH methanol solution is added to the round-bottom flask, and the reaction is allowed to proceed for 0.5 to 1 hour. After the reaction is complete, the solvent is evaporated to remove the residue, followed by elution and drying to obtain the crude product. In this step, TBAOH methanol solution is used to provide methoxy anions for nucleophilic reaction to prepare the target fullerene derivative; Step 4: The crude product obtained in Step 3 is separated and purified by high-performance liquid chromatography to obtain the target fullerene C. 60 Tetraaddition derivatives. High-performance liquid chromatography (HPLC) can achieve efficient separation, thus ensuring that the obtained fullerene derivatives have extremely high purity.

[0019] Preferably, the fullerene C60 The molar ratio of tetrabutylammonium hydroxide hydrate, benzyl bromide, and TBAOH methanol solution is 1:3~5:10~20:2~4.

[0020] In the technical solution of the present invention, the fullerene C 60 The molar ratio of tetrabutylammonium hydroxide hydrate, benzyl bromide, and TBAOH methanol solution is 1:3~5:10~20:2~4. Within this range, the reactants can react fully, achieving a high yield and effectively avoiding waste of the reagents. If the molar ratio of the reactants is lower than this range, the reaction may be incomplete; if the molar ratio is higher than this range, it may lead to excessive consumption of the reagents, resulting in unnecessary waste.

[0021] Preferably, the tetrabutylammonium hydroxide hydrate is TBAOH·3OH2O.

[0022] In the technical solution of this invention, the tetrabutylammonium hydroxide hydrate is TBAOH·3OH2O, and TBAOH·3OH2O facilitates the formation of C 60 Negative ions increase fullerene C 60 Reactivity.

[0023] Preferably, the inert gas is Ar or N2.

[0024] In the technical solution of this invention, the inert gas mentioned in step one is Ar or N2, which can effectively block air interference and avoid C 60 Negative ions are oxidized by oxygen in the air, providing protection for the reaction system and thus promoting the efficient and stable progress of the reaction.

[0025] Preferably, the organic solvent is o-dichlorobenzene or toluene.

[0026] In the technical solution of this invention, the organic solvent in step one is o-dichlorobenzene or toluene. Firstly, both o-dichlorobenzene and toluene are effective against fullerene C64. 60 Both solvents exhibit high solubility. Furthermore, both possess good chemical and thermal stability, which helps ensure the safety and stability of the overall reaction.

[0027] Preferably, the concentration of the TBAOH methanol solution is 0.5 ~ 1.5 mol / L.

[0028] In the technical solution of this invention, tetrabutylammonium hydroxide (TBAOH) reacts with methanol in a methanol solution to generate a methoxy anion. This anion then reacts with C... 60It undergoes a nucleophilic reaction, adding as a modifying group to the carbon cage of a fullerene. The methanol solution of TBAOH exhibits optimal reactivity in the range of 0.5–1.5 mol / L. Concentrations below 0.5 mol / L decrease the reaction rate, while concentrations above 1.5 mol / L may cause TBAOH precipitation, making it difficult to control the reaction conditions.

[0029] Preferably, the reaction temperature is 60 ~ 80 °C.

[0030] In the technical solution of this invention, the reaction temperature is 60-80°C. Mild reaction conditions contribute to the stable progress of the entire reaction process and are beneficial to the target fullerene C. 60 The formation of tetraaddition derivatives.

[0031] Preferably, the high-performance liquid chromatography method uses a pyrene-propyl bonded silica gel column (Buckyprep) as the separation column and toluene as the mobile phase, and separates and purifies the product using a high-performance liquid chromatograph to obtain a pure product.

[0032] In this invention, the purification technique used is high-performance liquid chromatography (HPLC). The specific operation is as follows: Buckyprep is used as the separation column, toluene is used as the mobile phase, the crude product is dissolved in toluene, and then separated and purified using HPLC to obtain a pure product. This technique achieves excellent purification results.

[0033] A third aspect of the invention is to provide the fullerene C 60 Tetra-addition derivatives are used as acceptor materials in the fabrication of photovoltaic devices in the field of organic solar cells.

[0034] The specific steps are as follows:

[0035] S1: Using poly-3-hexylthiophene (P3HT) as the donor material, and the fullerene C prepared in this invention... 60 Tetraaddition derivatives are used as acceptor materials. The donor and acceptor materials are dissolved in an organic solvent at a certain mass ratio and stirred to obtain a mixed solution.

[0036] S2: On conductive glass (ITO) that has been cleaned by ultrasonic cleaning and ultraviolet ozone cleaning machine (UVO), a layer of poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (PEDOT / PSS) with a thickness of 30 nm is spin-coated at 3000 rpm, and then dried at 150 °C for 10 min.

[0037] S3: Spin-coat the mixture obtained in S1 onto PEDOT / PSS and anneal at 150 °C for 10 min to obtain an annealed film;

[0038] S4: Vacuum evaporation of cathode modification layer and electrode on the thin film obtained in S3 to prepare photovoltaic device.

[0039] In the above process S1, the mass ratio of the donor material to the acceptor material is 1:0.5~1, the organic solvent is selected from o-dichlorobenzene and chlorobenzene, and the concentration of the mixed solution is 20 mg / mL.

[0040] In the above process S3, the spin coating speed is 1000 ~ 2500 rpm, and the spin coating time is 30 s.

[0041] In the above process S4, the cathode modification layer material is selected from lithium fluoride, calcium, and magnesium, and the electrode is selected from silver and aluminum.

[0042] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0043] (1) This invention provides a method for synthesizing fullerene C 60 The tetraaddition derivative method offers high selectivity, resulting in higher purity and yield of the target product. This highly selective synthetic approach simplifies subsequent separation and purification processes, thereby reducing production costs.

[0044] (2) The fullerene C of the present invention 60 The synthesis of the tetraaddition derivatives employs mild reaction conditions, thereby improving operational safety and reducing the performance requirements of equipment. The simple and efficient preparation method helps to simplify the production process, and its streamlined process is suitable for large-scale production.

[0045] (3) The fullerene C of the present invention 60 Tetraaddition derivatives can serve as acceptor materials in organic solar cells. Compared to widely used PCBMs, this fullerene derivative exhibits a higher open-circuit voltage as an acceptor material in photovoltaic devices. The fullerene C... 60 Tetraaddition derivatives possess excellent solubility and high electron mobility. In addition to being suitable for traditional organic solar cells, they are expected to be applied in the field of novel optoelectronic devices, such as field-effect transistors and organic photoconductors. Attached Figure Description

[0046] Figure 1 Fullerene C 60 Schematic diagram of the molecular structure of the tetraaddition derivative.

[0047] Figure 2 Fullerene C 60 Tetra-addition derivatives 1 H NMR spectrum

[0048] Figure 3 Fullerene C 60 Tetra-addition derivatives 13 C NMR spectrum

[0049] Figure 4 Fullerene C 60 UV-Vis absorption spectrum of tetraaddition derivatives

[0050] Figure 5 Fullerene C 60 Cyclic voltammetry curves of tetraaddition derivatives and PCBM

[0051] Figure 6 Fullerene C 60 Molecular conformation and LUMO orbital and energy level diagram of tetraaddition derivatives and PCBM

[0052] Figure 7 Current-voltage curve of the photovoltaic device prepared in Example 5

[0053] Figure 8 Current-voltage curves of photovoltaic devices prepared in Example 6 and the comparative example. Detailed Implementation

[0054] Unless otherwise specified, all instruments, materials, reagents, etc. used in the following embodiments can be purchased commercially. The usage methods of the instruments, materials, reagents, etc. shall be in accordance with the relevant operating instructions.

[0055] The technical solution of the present invention will be further illustrated and described below through embodiments, with the aim of enabling researchers in the field to better understand the technical solution of the present invention. However, the content of the present invention is not limited to the following embodiments, and those skilled in the art should understand that it is not limited to these embodiments.

[0056] Special note: In Examples 1-4 below, the addition of N molar equivalents of a certain drug refers to the amount of the drug to be added, which is the amount of fullerene C added in this example. 60 N times the amount of substance.

[0057] Example 1

[0058] The specific steps are as follows:

[0059] Under Ar protection, o-dichlorobenzene (30 mL) was first added to a round-bottom flask, followed by the addition of fullerene C. 60(50 mg) and 3 molar equivalents of TBAOH·30H2O (166.4 mg) were added to a round-bottom flask and heated in an oil bath at 60 °C. After reacting for 0.5 hours, 10 molar equivalents of benzyl bromide (82.4 μL) were added, and the reaction was continued for 1 hour. Then, 2 molar equivalents of TBAOH methanol solution (1.5 mol / L, 92.5 μL) were added, and the reaction was continued for 1 hour. After the reaction was completed, the solvent was evaporated to remove the crude product, which was then eluted and dried to obtain the crude product. The crude product was then separated and purified by high performance liquid chromatography (HPLC) with toluene as the mobile phase using a Buckyprep column to obtain the target fullerene C. 60 Tetra-addition derivatives.

[0060] Example 2

[0061] The specific steps are as follows:

[0062] Under Ar protection, toluene (30 mL) was first added to the round-bottom flask, followed by the addition of fullerene C. 60 (50 mg) and 5 molar equivalents of TBAOH·30H2O (277.3 mg) were added to a round-bottom flask and heated in an oil bath at 80 °C. After reacting for 0.5 hours, 20 molar equivalents of benzyl bromide (164.8 μL) were added, and the reaction was continued for 0.5 hours. Then, 4 molar equivalents of TBAOH methanol solution (0.5 mol / L, 555.1 μL) were added, and the reaction was continued for 1 hour. After the reaction was completed, the solvent was evaporated, and the crude product was obtained after elution and drying. The crude product was then separated and purified by high performance liquid chromatography (HPLC) with toluene as the mobile phase using a Buckyprep column to obtain the target fullerene C. 60 Tetra-addition derivatives.

[0063] Example 3

[0064] The specific steps are as follows:

[0065] Under N2 protection, toluene (30 mL) was first added to the round-bottom flask, followed by the addition of fullerene C. 60 (50 mg) and 4 molar equivalents of TBAOH·30H2O (221.9 mg) were added to a round-bottom flask and heated in an oil bath at 70 °C. After reacting for 0.5 hours, 15 molar equivalents of benzyl bromide (123.6 μL) were added, and the reaction was continued for 1 hour. Then, 3 molar equivalents of TBAOH methanol solution (1.2 mol / L, 173.5 μL) were added, and the reaction was continued for 0.5 hours. After the reaction was completed, the solvent was evaporated, and the crude product was obtained after elution and drying. The crude product was then separated and purified by high performance liquid chromatography (HPLC) with toluene as the mobile phase using a Buckyprep column to obtain the target fullerene C. 60 Tetra-addition derivatives.

[0066] Example 4

[0067] The specific steps are as follows:

[0068] Under N2 protection, first add o-dichlorobenzene (50 mL) to the round-bottom flask, then add fullerene C. 60 100 mg of benzyl bromide and 3 molar equivalents of TBAOH·30H2O (332.8 mg) were added to a round-bottom flask and heated in an oil bath at 80 °C for 1 hour. Then, 10 molar equivalents of benzyl bromide (164.8 μL) were added, and the reaction was continued for 1 hour. Next, 3 molar equivalents of TBAOH methanol solution (1.0 mol / L, 416.3 μL) were added, and the reaction was continued for 1 hour. After the reaction was complete, the solvent was evaporated, and the product was eluted and dried to obtain the crude product. The crude product was then separated and purified by high-performance liquid chromatography (HPLC) using toluene as the mobile phase and a Buckyprep column to obtain the target fullerene C. 60 Tetra-addition derivatives.

[0069] Fullerene C 60 Tetra-addition derivatives 1 H NMR, 13 C NMR and UV-Vis absorption spectroscopy test data. 1 H NMR(600 MHz, in CS2, CDCl3 was used as the external lock solvent) δ 7.54-7.51(m,2H), 7.48-7.45(m, 2H), 7.35(dt, J = 15.3, 7.7 Hz, 4H), 7.32-7.28(m, 1H),7.26-7.23 (m, 1H), 7.22 (d, J = 1.8 Hz, 1H), 7.21 (s, 2H), 7.18(s, 2H), 4.67(d, J = 13.4 Hz, 1H), 4.33(d, J = 12.7 Hz, 1H), 4.20(d, J = 13.4 Hz, 1H),3.99(s, 4H), 3.48–3.42 (m, 1H), 3.31 (d, J = 13.2 Hz, 1H). For example... Figure 2 . 1313C NMR (150 MHz, CS2 / CDCl3) (all 13C unless indicated) δ 160.74, 160.62, 154.65, 152.64, 150.39, 149.99, 149.67, 149.13(2C), 148.91, 148.56(2C), 147.93, 147.58, 147.51(3C), 147.19, 146.97, 146.76, 146.57(2C), 146.46, 146.40, 145.86(2C), 145.62, 145.46, 145.44, 145.38, 145.33, 145.30, 145.20, 145.04, 144.90(2C), 144.72, 144.57, 144.55, 144.22, 144.07, 143.76, 143.73, 143.14, 142.83, 142.70, 142.45, 141.58, 141.51, 141.48, 140.24, 139.13, 138.11, 136.90, 136.20, 135.86, 135.16(Ph), 134.79(Ph), 132.39(Ph), 132.32(2C, Ph), 131.16(2C, Ph), 130.67(2C, Ph), 128.57(2C, Ph), 128.24(2C, Ph), 127.73(2C, Ph), 127.53(Ph), 127.21(Ph), 126.93(Ph), 88.19(sp 3 , C 60 -O), 67.78(sp 3 , C 60 -CH2), 59.42(sp 3 , C 60 -CH2), 56.64(sp 3 , C 60 -CH2), 55.00(sp 3 , O-CH3), 47.22(sp 3 , CH2), 46.89(sp 3 , CH2), 44.78(sp 3 , CH2). For example Figure 3 . UV-vis(hexane) λ max / nm: 210, 250, 296, 361, 462. For example Figure 4 .

[0070] Fullerene C 60 Comparison of the LUMO level of the tetraaddition derivative and PCBM. Cyclic voltammetry data: Cyclic voltammetry was performed in a benzonitrile (PhCN) solution containing 0.1 M tetrabutylammonium perchlorate (TBAP) as the supporting electrolyte, using ferrocene as an internal standard. The working electrode was a glassy carbon electrode (GCE), the counter electrode was a platinum wire electrode (Pt), and the reference electrode was a saturated calomel electrode (SCE). The scan rate was 100 mV / s. Figure 5 Fullerene C 60 The first reduction half-wave potential (E) of the tetraaddition derivative 1 / 2 red1 The value is -1.21 V, calculated using the formula LUMO = −(4.80 + E). 1 / 2 red1 The LUMO energy level was calculated to be -3.59 eV based on the given eV; under the same conditions, the first reduction half-wave potential of PCBM was -1.00 V, and its LUMO energy level was calculated to be -3.80 eV based on the formula; cyclic voltammetry results showed that the fullerene C 60 The LUMO level of the tetraaddition derivative is higher than that of the PCBM. Theoretical calculation and simulation data: Density functional theory (DFT) calculations at the B3LYP / 6-31G(d) level are as follows... Figure 6 As shown, fullerene C 60 The calculated LUMO level of the tetraaddition derivative is -2.90 eV, while that of PCBM is -3.09 eV. (Fullerene C...) 60 The tetraaddition derivative exhibits a higher LUMO energy level than PCBM. This theoretical calculation and simulation result is consistent with the trend of data obtained from cyclic voltammetry tests, thus strongly confirming the potential applicability of this derivative as an electron acceptor material.

[0071] Example 5

[0072] The specific steps are as follows:

[0073] S1: Using P3HT as the donor material, fullerene C 60 The tetraaddition derivative was used as the acceptor material. The donor material and the acceptor material were dissolved in o-dichlorobenzene at a mass ratio of 1:0.5 and stirred to obtain a mixed solution with a concentration of 20 mg / mL.

[0074] S2: On conductive glass (ITO) that has been ultrasonically cleaned and treated with UVO, spin-coat a layer of PEDOT / PSS with a thickness of 30 nm at 3000 rpm, and then dry at 150 °C for 10 min.

[0075] S3: Spin-coat the mixture obtained in S1 onto PEDOT / PSS at a speed of 1500 rpm for 30 s, and then anneal at 150 °C for 10 min to obtain an annealed film.

[0076] S4: On the thin film obtained in S3, Ca and Al are deposited onto the top layer with thicknesses of 10 nm and 150 nm, respectively, to prepare a photovoltaic device.

[0077] At AM 1.5 100 mW / cm 2 Under light intensity, the open-circuit voltage of the photovoltaic device prepared in Example 5 is 0.79V, and the short-circuit current is 2.99 mA / cm². 2 The fill factor is 38.48%, and the photoelectric conversion efficiency is 0.91%. The current-voltage curve of the photovoltaic device is shown below. Figure 7 As shown.

[0078] Example 6

[0079] The specific steps are as follows:

[0080] S1: Using P3HT as the donor material, fullerene C 60 The tetraaddition derivative is used as the acceptor material. The donor material and the acceptor material are dissolved in o-dichlorobenzene at a mass ratio of 1:1 and stirred to obtain a mixed solution with a concentration of 20 mg / mL.

[0081] S2: On conductive glass (ITO) that has been ultrasonically cleaned and treated with UVO, spin-coat a layer of PEDOT / PSS with a thickness of 30 nm at 3000 rpm, and then dry at 150 °C for 10 min.

[0082] S3: Spin-coat the mixture obtained in S1 onto PEDOT / PSS at a speed of 1500 rpm for 30 s, and then anneal at 150 °C for 10 min to obtain an annealed film.

[0083] S4: On the thin film obtained in S3, Ca and Al are deposited onto the top layer with thicknesses of 10 nm and 150 nm, respectively, to prepare a photovoltaic device.

[0084] At AM 1.5 100 mW / cm 2 Under light intensity, the open-circuit voltage of the photovoltaic device prepared in Example 6 is 0.78V, and the short-circuit current is 3.31 mA / cm². 2 The fill factor is 41.40%, and the photoelectric conversion efficiency is 1.07%. The current-voltage curve of the photovoltaic device is shown below. Figure 8 As shown.

[0085] Comparative Example 1

[0086] The difference between this embodiment and embodiment 6 is that the spin coating speed is 1000 rpm in process S3.

[0087] The photovoltaic device prepared in Comparative Example 1 was tested and found to have an open-circuit voltage of 0.78 V and a short-circuit current of 3.18 mA / cm². 2 The fill factor is 40.77%, and the photoelectric conversion efficiency is 1.01%. The current-voltage curve of the photovoltaic device is shown below. Figure 8 As shown.

[0088] Comparative Example 2

[0089] The difference between this embodiment and embodiment 6 is that the spin coating speed is 2000 rpm in process S3.

[0090] The photovoltaic device prepared in Comparative Example 2 was tested and found to have an open-circuit voltage of 0.80 V and a short-circuit current of 2.95 mA / cm². 2 The fill factor is 43.40%, and the photoelectric conversion efficiency is 1.02%. The current-voltage curve of the photovoltaic device is shown below. Figure 8 As shown.

[0091] Comparative Example 3

[0092] The difference between this embodiment and embodiment 6 is that the spin coating speed is 2500 rpm in process S3.

[0093] The photovoltaic device prepared in Comparative Example 3 was tested and found to have an open-circuit voltage of 0.80 V and a short-circuit current of 3.02 mA / cm². 2 The fill factor is 43.73%, and the photoelectric conversion efficiency is 1.05%. The current-voltage curve of the photovoltaic device is shown below. Figure 8 As shown.

[0094] Results Analysis: Analysis of the data from Example 6 and Comparative Examples 1-3 revealed that the relationship between photoelectric conversion efficiency and spin coating speed was not significant in process S3. The photovoltaic device exhibited the highest photoelectric conversion efficiency at a spin coating speed of 1500 rpm. As the spin coating speed increased from 1000 rpm to 1500 rpm, the photoelectric conversion efficiency of the prepared photovoltaic device showed an increasing trend with increasing speed. However, further increases in speed beyond 1500 rpm did not promote an increase in the photoelectric conversion efficiency of the photovoltaic device.

[0095] The embodiments and comparative examples described above are merely preferred embodiments of the present invention and do not represent all possible embodiments. The scope of protection of this patent covers all requirements set forth in the claims. Any minor, non-inventive modifications to the experimental steps, processes, and techniques involved in this patent are considered to be within the scope of protection of this patent.

Claims

1. A fullerene C 60 Tetraaddition derivative, with the molecular formula 1-CH3O-2,4,15-(C6H5CH2)3C 60 Its characteristics are, The fullerene C 60 The tetra-adduct derivative has a structure as shown in formula I. Formula I 2. A fullerene C 60 The process for the preparation of tetra-adduct derivatives is characterized in that, The preparation steps include the following: Step 1: Under inert gas protection, add fullerene C to a round-bottom flask sequentially. 60 An organic solvent and tetrabutylammonium hydroxide hydrate are added, and the mixture is stirred and reacted at 60-80 °C for 0.5-1 hour. The organic solvent is o-dichlorobenzene or toluene. Step 2: Based on Step 1, add benzyl bromide to the round-bottom flask and react for 0.5 to 1 hour; Step 3: Based on Step 2, add TBAOH methanol solution to the round-bottom flask, react for 0.5 to 1 hour, after the reaction is complete, evaporate to remove the solvent, and then wash and dry to obtain the crude product; Step four: the crude product obtained in step three is separated and purified by high performance liquid chromatography to obtain the target fullerene C 60 Tetrakis-adduct derivative.

3. The fullerene C 60 Process for the preparation of tetra-adduct derivatives, characterized in that, The fullerene C 60 The molar ratio of tetrabutylammonium hydroxide hydrate, benzyl bromide, and TBAOH methanol solution is 1:3~5:10~20:2~4.

4. The fullerene C 60 Process for the preparation of tetra-adduct derivatives, characterized in that, The tetrabutylammonium hydroxide hydrate is TBAOH·30H2O.

5. The fullerene C 60 Process for the preparation of tetra-adduct derivatives, characterized in that, The inert gas is Ar or N2.

6. The fullerene C 60 Process for the preparation of tetra-adduct derivatives, characterized in that, The concentration of the TBAOH methanol solution is 0.5 ~ 1.5 mol / L.

7. The fullerene C 60 Process for the preparation of tetra-adduct derivatives, characterized in that, The high-performance liquid chromatography method uses a pyrene-propyl-bonded silica gel column as the separation column and toluene as the mobile phase. The separation and purification are performed by a high-performance liquid chromatograph to obtain a pure product.

8. The fullerene C according to claim 1 60 Tetra-addition derivatives are used as acceptor materials in the fabrication of photovoltaic devices in the field of solar cells.

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