A class of porphyrin-based quinoline organic photovoltaic materials, and preparation method and application thereof

Abstract

The application belongs to the field of organic small molecule photovoltaic materials, and discloses a kind of porphyrin-based quinoline organic photovoltaic material and a preparation method and application thereof.The chemical structure of the porphyrin-based quinoline photovoltaic material according to the application is shown in formula (I), which takes a porphyrin ring as a center electron-donating unit, connects two cheap quinoline electron-accepting units on two symmetrical meso positions of the porphyrin to synthesize a target molecule, forms a push-pull electron effect, can effectively enhance intramolecular charge transfer and broaden absorption.By changing side groups of the quinoline, absorption and energy levels of the molecule are effectively adjusted, and the purpose of further optimizing material performance is achieved.The application proves the possibility of using quinoline with simple synthesis conditions as a porphyrin electron-accepting unit, and provides a new direction for molecular design of porphyrin-based quinoline materials for organic solar cells.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of organic small molecule photovoltaic materials, and particularly relates to a kind of porphyrin-based quinoline organic photovoltaic material and a preparation method and application thereof. BACKGROUND

[0002] Traditional fossil energy is facing a serious energy crisis on the one hand, and on the other hand, it also causes great environmental pollution while being applied. Solar energy is abundant, easy to obtain, clean and green. Organic solar cells for converting solar energy into electrical energy have been widely studied. Organic solar cells convert photons into electricity through organic photoactive materials, and the efficiency of single-junction devices has exceeded 19%, and the certified efficiency of tandem cell devices has exceeded 20%. The material structure is rich, and can be processed by solution and roll-to-roll large-scale printing. It is conducive to the design of low-toxic or non-toxic devices. At the same time, it is flexible and light, and can be used for wearing. It can be made into a semi-transparent device for green building, and has great application prospects. Therefore, developing active materials with high efficiency and stability is the focus of current research on organic solar cells.

[0003] Porphyrin and its derivatives are widely used as donor materials in organic solar cells due to their wide absorption range, high extinction coefficient, and strong molecular adjustability. Among them, porphyrin derivatives with pyrrolopyrroloquinoline as an electron-accepting unit perform best. However, the synthesis of pyrrolopyrroloquinoline intermediates is quite complicated. Two of the three-step reactions require inert gas protection and high temperature. After each reaction, column chromatography purification is required, which leads to high prices of pyrrolopyrroloquinoline, hindering the commercialization of organic solar cells. SUMMARY

[0004] To solve the shortcomings and deficiencies of the prior art, the primary purpose of the present application is to provide a kind of porphyrin-based quinoline organic photovoltaic material. In the present application, porphyrin ring is used as an electron-donating unit, and quinoline is connected to the two symmetric meso positions of porphyrin as an electron-accepting unit. The use of triple bond connection enhances the planarity of the molecule, which is conducive to charge transfer. At the same time, by adjusting the functional groups of quinoline, the absorption and energy level of the molecule are effectively adjusted, achieving the purpose of further optimizing the material performance.

[0005] Another purpose of the present application is to provide a preparation method of the above-mentioned porphyrin-based quinoline organic photovoltaic material.

[0006] Still another purpose of the present application is to provide the application of the above-mentioned porphyrin-based quinoline organic photovoltaic material.

[0007] The purposes of the present application are achieved by the following technical solutions:

[0008] A kind of porphyrin-based quinoline organic photovoltaic material has the following chemical structure:

[0009]

[0010] wherein R1 is an alkyl group having 16 carbon atoms; and R2 is a hydrogen atom, a fluorine atom, or an alkyl or alkoxy group having 1 to 4 carbon atoms.

[0011] Preferably, R1 is at least one of (2-hexyl)decyl group, n-hexadecyl group.

[0012] Preferably, R2 is at least one of H atom, fluorine atom, methyl group, methoxy group, isopropyl group, n-butyl group, t-butyl group.

[0013] The preparation method of the porphyrin-based quinoline organic photovoltaic material includes the following steps:

[0014] (1) 4-bromophenylene diamine is dissolved in an organic solvent, benzoin or its derivative is added, and the reaction is carried out at room temperature for 1-30 minutes, water is added for quenching, and extraction is carried out to obtain compound 1, and the structural formula is as follows:

[0015]

[0016] (2) Compound 2 is dissolved in an organic solvent, N-bromosuccinimide (NBS) is added at low temperature, and the reaction is carried out for 0.5 hours, and the reaction is continued at room temperature for 0.5-5 hours to obtain compound 3;

[0017]

[0018] (3) Compound 3 is dissolved in an organic solvent, zinc acetate is added, and the reaction is carried out at room temperature for 0.5-8 hours to obtain compound 4;

[0019]

[0020] (4) Compound 4 is dissolved in an organic solvent, trimethylsilylethynyl is added, and the reaction is carried out at 60-100°C for 12-48 hours under the action of a catalyst to obtain compound 5;

[0021]

[0022] (5) Compound 5 is dissolved in an organic solvent, a tetrabutylammonium fluoride solution (dissolved in tetrahydrofuran, THF) is added at room temperature, and the reaction is carried out for 5-30 minutes, water is added for quenching, extraction is carried out, and rotary evaporation is carried out to obtain compound 6 which is directly used in the next step;

[0023] (6) Compound 6 and compound 1 are heated and refluxed in an organic solvent under the action of a catalyst for 12-72 hours to obtain the target compound, wherein R1 and R2 are as defined above.

[0024] In the above preparation method, the quinoxaline electron-withdrawing unit is synthesized from the simplest and cheapest raw material through one-step reaction under mild conditions with few by-products, thereby reducing the production cost of the organic solar cell.

[0025] Preferably, the molar ratio of the 4-bromo-o-phenylenediamine to the benzil or derivative thereof in step (1) is 1:1-1:2.

[0026] Preferably, the organic solvent in step (1) is one of methanol and ethanol.

[0027] Preferably, the organic solvent in step (2) is one of chloroform and dichloromethane.

[0028] Preferably, the molar ratio of the compound 2 to N-bromosuccinimide in step (2) is 1:2-1:4.

[0029] Preferably, the organic solvent in step (3) is chloroform or a mixed solution of dichloromethane and methanol; the molar amount of chloroform is 1000-6000 times that of the compound 3, and the volume ratio of chloroform to methanol is 6:1-3:1.

[0030] Preferably, the molar ratio of the compound 3 to zinc acetate in step (3) is 1:4-1:10.

[0031] Preferably, the organic solvent in step (4) is a mixed solvent of tetrahydrofuran and triethylamine; the molar amount of tetrahydrofuran is 2000-3000 times that of the compound 4, and the volume ratio of tetrahydrofuran to triethylamine is 3:1-5:1.

[0032] Preferably, the molar ratio of the compound 4 to trimethylsilylacetylene in step (4) is 1:2-1:4.

[0033] Preferably, the catalyst in step (4) is palladium dichloride bis(triphenylphosphine) and cuprous iodide. The molar amount of each of the two is 0.15 times that of the compound 4.

[0034] Preferably, the organic solvent in step (5) is tetrahydrofuran; the molar amount of tetrahydrofuran is 2000-4000 times that of the compound 5.

[0035] Preferably, the molar ratio of the compound 5 to tetrabutylammonium fluoride in step (5) is 1:5-1:7.

[0036] Preferably, the molar ratio of the compound 6 to the compound 1 in step (6) is 1:2-1:4.

[0037] The organic solvent in step (6) is a mixed solvent of tetrahydrofuran and triethylamine; the molar amount of tetrahydrofuran is 1000-4000 times of the molar amount of compound 6, and the volume ratio of tetrahydrofuran and triethylamine is 2:1-6:1.

[0038] Preferably, the catalyst in step (6) is tetrakis(triphenylphosphine)palladium, or is tris(dibenzylideneacetone)dipalladium, tris(o-methylphenyl)phosphine and cuprous iodide; the molar amount of tetrakis(triphenylphosphine)palladium is 0.1-0.3 times of the molar amount of compound 6; the molar ratio of tris(dibenzylideneacetone)dipalladium, tris(o-methylphenyl)phosphine and cuprous iodide to compound 6 is 6:48:1:20.

[0039] The above-mentioned porphyrin-based quinoline organic photovoltaic material takes a porphyrin ring as an electron-donating group, connects an electron-accepting unit through a triple bond, forms an effective push-pull electron effect, adjusts molecular absorption and energy levels and is stacked in the same level.

[0040] The above-mentioned porphyrin-based quinoline organic photovoltaic material is preferably applied in an organic solar cell.

[0041] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0042] (1) The present application connects an electron-accepting unit to two symmetrical meso positions of a porphyrin through a triple bond, enhances the overall conjugation of the molecule, makes intramolecular charge transfer more smooth, and widens spectral absorption and enhances the light absorption capacity of the active layer material due to more ordered stacking.

[0043] (2) The present application changes the electron-accepting capacity of the electron-accepting group conjugated with the porphyrin, effectively adjusts the energy level of the material, and thus designs a donor-acceptor material with more matched energy levels.

[0044] (3) The present application changes the side group of the electron-accepting unit of the porphyrin to adjust the surface tension of the molecule, optimizes the phase separation of the molecule and the acceptor material, and has an important influence on the photovoltaic performance of the subsequently prepared organic solar cell device.

[0045] (4) The preparation method of the present application has low raw material cost, short reaction time and simple reaction conditions; the synthesis step of the electron-accepting unit only needs to be carried out in air at room temperature, and additional heating is not required, which greatly reduces the production cost. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 The nuclear magnetic hydrogen spectrum of the porphyrin-based quinoline organic photovoltaic material prepared in Example 1.

[0047] Figure 2 The nuclear magnetic hydrogen spectrum of the porphyrin-based quinoline organic photovoltaic material prepared in Example 2.

[0048] Figure 3 UV-visible light absorption spectrum of a solution and thin film of the porphyrin-based quinoxaline organic photovoltaic material prepared in Example 1.

[0049] Figure 4 UV-visible light absorption spectrum of a solution and thin film of the porphyrin-based quinoxaline organic photovoltaic material prepared in Example 2.

[0050] Figure 5 Photovoltaic cells prepared from the porphyrin-based quinoxaline organic photovoltaic materials obtained in Examples 1 and 2 have a power conversion efficiency of 0.5% under AM 1.5, 100 mW / cm 2 Current-voltage curve under light irradiation. DETAILED DESCRIPTION

[0051] The present application will be described in further detail below with reference to Examples and drawings, but the embodiments of the present application are not limited thereto. In the Examples of the present application, unless specific conditions are noted, they are carried out according to conventional conditions or the conditions recommended by the manufacturers. The raw materials, reagents, etc. used, for which the manufacturers are not noted, are all conventional products that can be purchased on the market.

[0052] Example 1

[0053] Preparation of EHDPP-Por molecule: R1 is (2-hexyl)decyl group, and R2 is fluorine atom.

[0054]

[0055] The reaction process of Example 1 is as follows:

[0056] (1) 4-Bromo-o-phenylenediamine (370 mg, 2 mmol) was added to a flask, 10 mL of methanol was used as a solvent, after complete dissolution, difluorobenzil (492 mg, 2 mmol) was added, and the reaction was carried out for 1 minute, then quenched with 10 mL of water, extracted with ethyl acetate / water, and the solvent was evaporated with a rotary evaporator, and purified by silica gel chromatography column using petroleum ether and ethyl acetate as eluent, and recrystallized to obtain compound 1 (473 mg, yield 60%).

[0057] (2) Compound 2 (800 mg, 0.83 mmol) was added to a flask, 100 mL of chloroform solution was used as a solvent, and refluxed for 4 hours, then NBS (362 mg, 2.04 mmol) was added at 0°C, and the reaction was carried out for 0.5 hours, then continued at room temperature, and the reaction was terminated by TLC plate detection, the solvent was evaporated with a rotary evaporator, and purified by silica gel chromatography column using petroleum ether and dichloromethane as eluent, and recrystallized to obtain compound 3 (819 mg, yield 90%).

[0058] (3) In a 250 mL reaction flask, compound 3 (875 mg, 0.82 mmol) and zinc acetate (898 mg, 4.1 mmol) were added, and 80 mL of chloroform and 8 mL of methanol were added. The reaction was carried out at room temperature for one hour, and TLC plate was used to detect the termination of the reaction. The product was obtained by silica gel column chromatography using dichloromethane as the eluent and recrystallization, and the yield was 919 mg (96%).

[0059] (4) Under argon, compound 4 (919 mg, 0.79 mmol), 40 mL of super dry tetrahydrofuran (THF) and 20 mL of super dry triethylamine (NEt3) were added to a two-neck flask, and then 55 mg (0.1 eq) of bis(triphenylphosphine)palladium dichloride and 15 mg (0.1 eq) of cuprous iodide were added. After 10 min of argon blowing, trimethylsilyacetylene (187 mg, 1.89 mmol) was injected with a long needle, and the reaction was heated to reflux at 80°C for 24 hours in the dark. After the reaction was completed, the solvent was dried by rotary evaporation, and the product was purified by silica gel column chromatography using petroleum ether and dichloromethane as the eluent, and recrystallized from chloroform and methanol to obtain compound 5 as a green solid (544 mg, 58% yield).

[0060] (5) Compound 5 (544 mg, 0.48 mmol) was dissolved in 33.6 mL of THF, and a solution of tetrabutylammonium fluoride (TBAF) (0.96 mL, 1M in THF) was added. The reaction was carried out at room temperature for 10 min, and then quenched by adding water. The product was obtained by water / dichloromethane extraction and drying by rotary evaporation, and directly used in the next step.

[0061] (6) Under argon, compound 6 (484 mg, 0.46 mmol), compound 1 (437 mg, 1.11 mmol) were added to a 100 mL two-neck round-bottom flask, and dissolved in 60 mL of THF and 30 mL of Et3N super dry solvent. Then, tris(dibenzylideneacetone)dipalladium (130 mg, 0.14 mmol), cuprous iodide (4.4 mg, 0.023 mmol), and tris(o-methylphenyl)phosphine (360 mg, 1.1 mmol) were added. The reaction system was replaced with argon three times, and then the reaction was carried out at 80°C in the dark for 36 hours. After the reaction was completed, the solvent was dried by rotary evaporation, and the product was purified by silica gel column chromatography using petroleum ether and dichloromethane as the eluent, GPC column chromatography using THF as the eluent, and recrystallization from chloroform and methanol to obtain the final product FQuin-Por (460 mg, 59% yield). 1H NMR (400 MHz, Chloroform-d) δ 9.72 (d, J = 4.5 Hz, 4H), 8.96 (d, J = 4.5 Hz, 4H), 8.48 (s, 2H), 8.13 (s, 4H), 7.88 (d, J = 6.7 Hz, 2H), 7.80 (d, J = 8.6 Hz, 2H), 7.58 - 7.48 (m, 8H), 7.32 (d, J = 8.4 Hz, 4H), 7.08 (dt, J = 22.3, 8.6 Hz, 8H), 4.19 (d, J = 5.6 Hz, 4H), 2.03 (d, J = 18.1 Hz, 2H), 1.73 - 1.33 (m, 48H), 0.97 (dd, J = 17.4, 5.5 Hz, 12H), see Figure 6. Figure 1 .

[0062] The porphyrin organic small molecule photovoltaic material prepared in this example was dissolved in a chloroform solution with a mass concentration of 10 -5 -10 -4 mol / L, and the UV-Vis absorption spectrum of the obtained chloroform solution is shown in Figure 5. Figure 3 .

[0063] The porphyrin organic small molecule photovoltaic material prepared in this example was prepared into a thin film with a thickness of about 70 nm by spin coating, and the UV-Vis absorption spectrum of the thin film is shown in Figure 6. Figure 4 .

[0064] A forward device was prepared using the porphyrin molecule of this example as the donor material and the small molecule L8-BO (CAS: 2668341-40-8) as the acceptor material to study the photovoltaic performance. The structure of the device was ITO / PEDOT:PSS / active layer / PFN-Br / Ag, and the mass ratio of the active layer donor to acceptor was 1:0.9. The current-voltage curve (J-V curve) under light is shown in Figure 7. Figure 5 The prepared device has a photoelectric conversion efficiency of 0.55%, a short-circuit current of 2.24 mA / cm 2 , an open-circuit voltage of 0.64 V, and a fill factor of 38.26%.

[0065] The photoelectric conversion efficiency of the heterojunction cell prepared in this example is the highest photoelectric conversion efficiency obtained after optimizing the donor to acceptor ratio to prepare an active layer material with a donor to acceptor mass ratio of 1:0.9 and performing thermal annealing.

[0066] Example 2

[0067] Preparation of MeOQuin-Por molecule: R1 is (2-hexyl)decyl, R2 is methoxy. The main difference between this example and Example 1 is that compound 7 is prepared by using 3,3'-dimethoxybenzil instead of difluorobenzil in step (1) of preparing compound 1, and the preparation of compound 3 to compound 6 is the same as that of Example 1.

[0068]

[0069] The reaction procedure of Example 2 is shown below

[0070] (1) 4-Bromoresorcinol (370 mg, 2 mmol) was added to a flask, 10 mL of methanol as solvent, after complete dissolution, 3,3'-dimethoxybenzil (540 mg, 2 mmol) was added, reacted for 1 minute, quenched with 10 mL of water, extracted with ethyl acetate / water, evaporated to dryness with a rotary evaporator, purified with a silica gel column using petroleum ether and ethyl acetate as eluent, and recrystallized to obtain compound 7 (502 mg, yield 60%).

[0071] (2) Compound 2 (800 mg, 0.83 mmol) was added to a flask, 100 mL of chloroform solution as solvent, refluxed for 4 hours, 0°C, NBS (362 mg, 2.04 mmol) was added, reacted for 0.5 hours, then continued to react at room temperature, TLC plate detection reaction termination, rotary evaporator spin dry solvent, silica gel chromatography column with petroleum ether and dichloromethane as eluent, recrystallized to obtain compound 3 (819 mg, yield 90%).

[0072] (3) Compound 3 (875 mg, 0.82 mmol) and zinc acetate (898 mg, 4.1 mmol) were added to a 250 mL reaction bottle, 80 mL of chloroform and 8 mL of methanol mixed solvent were added, and reacted at room temperature for one hour. TLC plate detection reaction termination, over silica gel chromatography column, dichloromethane as eluent, recrystallized to obtain compound 4 (919 mg, yield 96%).

[0073] (4) Under argon conditions, compound 4 (919 mg, 0.79 mmol), 40 mL of super dry tetrahydrofuran (THF) and 20 mL of super dry triethylamine (NEt3) were added to a flask, then 55 mg (0.1 eq) of bis(triphenylphosphine)palladium dichloride and 15 mg (0.1 eq) of cuprous iodide were added, 10 min argon was passed, then trimethylsilylethynyl (187 mg, 1.89 mmol) was injected with a long needle, and heated to reflux at 80°C under light shielding conditions for 24 hours. After the reaction was completed, the solvent was evaporated to dryness with a rotary evaporator, and purified with a silica gel chromatography column using petroleum ether and dichloromethane as eluent, and recrystallized with chloroform and methanol to obtain compound 5 as a green solid (544 mg, yield 58%).

[0074] (5) Compound 5 (544 mg, 0.48 mmol) was dissolved in 33.6 mL of THF, and a solution of tetrabutylammonium fluoride (TBAF) (0.96 mL, 1 M in THF) was added. The reaction was allowed to proceed at room temperature for 10 min, and then quenched by adding water. The reaction was extracted with water / dichloromethane, and then dried by rotary evaporation to obtain compound 6, which was directly used in the next step.

[0075] (6) Compound 6 (484 mg, 0.46 mmol) and compound 7 (463 mg, 1.11 mmol) were dissolved in 60 mL of THF and 30 mL of Et3N, and then tetrakis(triphenylphosphine)palladium (110 mg, 0.092 mmol) was added. The reaction system was degassed three times, and then the reaction was allowed to proceed at 80°C for 36 h in the dark. After the reaction was completed, the reaction was dried by rotary evaporation, and then subjected to silica gel column chromatography using petroleum ether and dichloromethane as eluents. The product was subjected to GPC column chromatography using THF as an eluent, and then recrystallized from chloroform / methanol to obtain the final product MeOQuin-Por (486 mg, yield 61%). 1 H NMR (400 MHz, Chloroform-d) δ 9.76 (d, J = 4.5 Hz, 4H), 8.96 (d, J = 4.5 Hz, 4H), 8.69 (d, J = 1.7 Hz, 2H), 8.15 (dd, J = 8.6, 1.8 Hz, 2H), 8.11 (t, J = 3.2 Hz, 4H), 8.09 (d, J = 2.6 Hz, 2H), 7.57 (t, J = 8.8 Hz, 8H), 7.33 (s, 4H), 6.98 - 6.86 (m, 8H), 4.18 (d, J = 5.6 Hz, 4H), 3.85 (d, J = 13.2 Hz, 12H), 2.06 - 1.98 (m, 2H), 1.73 - 1.33 (m, 48H), 0.96 (d, J = 20.7 Hz, 12H). See Figure 2

[0076] The porphyrin organic small-molecule photovoltaic material prepared in this example was dissolved in a chloroform solution with a mass concentration of 10 -5 -10 -4 mol / L. The UV-visible absorption spectrum of the obtained chloroform solution is shown in Figure 3 .

[0077] The porphyrin organic small-molecule photovoltaic material prepared in this example was prepared into a thin film with a thickness of about 70 nm by spin coating. The UV-visible absorption spectrum of the thin film is shown in Figure 4 .

[0078] A heterojunction cell was prepared by using the porphyrin molecule of the present embodiment as a donor material and a small molecule L8-BO (CAS: 2668341-40-8) as an acceptor material, and the photovoltaic performance was studied. The structure of the device was ITO / PEDOT:PSS / active layer / PDINO / Ag, the mass ratio of the active layer to the acceptor was 1:1, and the current-voltage curve (J-V curve) under light was as shown in Figure 5 The prepared device had a photoelectric conversion efficiency of 2.95%, a short-circuit current of 7.53 mA / cm 2 , an open-circuit voltage of 0.73 V, and a fill factor of 53.62%.

[0079] The photoelectric conversion efficiency of the heterojunction cell prepared in the present embodiment was the highest photoelectric conversion efficiency obtained after optimizing the donor / acceptor ratio to 1:0.9 for the preparation of the active layer material and performing thermal annealing.

[0080] It can be seen from the small molecule donor photovoltaic materials prepared in Embodiment 1 and Embodiment 2 that the two kinds of donor photovoltaic materials have similar absorption. In solution, the Soret band and the absorption peak of quinoxaline are located at about 470 nm and 680 nm, respectively; in the thin film state, the donor molecules form ordered packing, and the absorption of porphyrin and quinoxaline is obviously widened and red-shifted. The absorption edge of the molecule of Embodiment 1 is 738 nm, and the absorption edge limit of the molecule of Embodiment 2 is 746 nm.

[0081] The synthesis methods of other small molecule photovoltaic materials based on porphyrin and connected to the light absorption unit through substitution at two meso positions are similar to the above method, and will not be described here.

[0082] The above embodiments are preferred embodiments of the present application, but the embodiments of the present application are not limited to the above embodiments, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application are equivalent replacement methods and are included in the protection scope of the present application.

Claims

1. A class of porphyrin-based quinoxaline organic photovoltaic materials characterized in that, A compound having a chemical structure as shown in formula (I): wherein R1 is an alkyl group having 16 carbon atoms; R2 is a hydrogen atom, a fluorine atom, or an alkyl or alkoxy group having 1 to 4 carbon atoms.

2. The class of porfyrin-based quinoxaline organic photovoltaic materials according to claim 1, characterized by, R1 is at least one of (2-hexyl)decyl and n-hexadecyl.

3. The class of porfyrin-based quinoxaline organic photovoltaic materials according to claim 1, characterized by, R2 is at least one of a hydrogen atom, a fluorine atom, a methyl group, a methoxy group, an isopropyl group, and a n-butyl group.

4. Process for the preparation of the porphyrazine-based quinoxaline organic photovoltaic material according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: (1) dissolving 4-bromophenylene diamine in an organic solvent, adding benzoin or a derivative thereof, and reacting at room temperature for 1-30 minutes, quenching with water, and extracting to obtain compound 1, which has the following structure: (2) dissolving compound 2 in an organic solvent, adding N-bromosuccinimide at low temperature, and reacting for 0.5 hours, and then continuing to react at room temperature for 0.5-5 hours to obtain compound 3; (3) dissolving compound 3 in an organic solvent, adding zinc acetate, and reacting at room temperature for 0.5-8 hours to obtain compound 4; (4) dissolving compound 4 in an organic solvent, adding trimethylsilylacetylene under the action of a catalyst, and reacting at 60-100°C for 12-48 hours to obtain compound 5; (5) dissolving compound 5 in an organic solvent, adding a tetrabutylammonium fluoride solution at room temperature, stirring and reacting for 5-30 minutes, quenching with water, and extracting to obtain compound 6; (6) heating and refluxing compound 6 and compound 1 in an organic solvent under the action of a catalyst for 12-72 hours to obtain the target compound, wherein R1 and R2 are as defined in claim 1.

5. The preparation method according to claim 4, characterized in that, The molar ratio of 4-bromophenylene diamine to benzoin or a derivative thereof in step (1) is 1:1-1:

2. The organic solvent in step (1) is one of methanol and ethanol.

6. The preparation method according to claim 4, characterized in that, The organic solvent in step (2) is one of chloroform and dichloromethane. The molar ratio of compound 2 to N-bromosuccinimide in step (2) is 1:2-1:

4. The organic solvent in step (3) is chloroform or a mixed solution of dichloromethane and methanol; the molar amount of chloroform is 1000-6000 times the molar amount of compound 3; and the volume ratio of chloroform to methanol is 6:1-3:

1. The molar ratio of compound 3 to zinc acetate in step (3) is 1:4-1:

10.

7. The preparation method according to claim 4, characterized in that, The organic solvent in step (4) is a mixed solvent of tetrahydrofuran and triethylamine; the molar amount of tetrahydrofuran is 2000-3000 times the molar amount of compound 4; and the volume ratio of tetrahydrofuran to triethylamine is 3:1-5:

1. The molar ratio of compound 4 to trimethylsilylacetylene in step (4) is 1:2-1:

4. The catalyst in step (4) is both bis(triphenylphosphine)palladium dichloride and cuprous iodide, and the molar amount of each is 0.15 times the molar amount of compound 4.

8. The preparation method according to claim 4, characterized in that, The organic solvent in step (5) is tetrahydrofuran; and the molar amount of tetrahydrofuran is 2000-4000 times the molar amount of compound 5. The molar ratio of compound 5 to tetrabutylammonium fluoride in step (5) is 1:5-1:

7.

9. The preparation method according to claim 4, characterized in that, The molar ratio of compound 6 to compound 1 in step (6) is 1:2-1:

4. The organic solvent in step (6) is a mixed solvent of tetrahydrofuran and triethylamine; the molar amount of tetrahydrofuran is 1000-4000 times of the molar amount of compound 6, and the volume ratio of tetrahydrofuran to triethylamine is 2:1-6:1; The catalyst in step (6) is tetrakis(triphenylphosphine)palladium, or is tris(dibenzylideneacetone)dipalladium, tris(o-methylphenyl)phosphine and cuprous iodide; the molar amount of tetrakis(triphenylphosphine)palladium is 0.1-0.3 times of the molar amount of compound 6; the molar ratio of tris(dibenzylideneacetone)dipalladium, tris(o-methylphenyl)phosphine and cuprous iodide to compound 6 is 6:48:1:

20.

10. Use of the porphyrin-based quinoxaline organic photovoltaic material according to any one of claims 1-3 in an organic solar cell.

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