Organic solar cell small molecule donor material, and preparation method and application thereof

Abstract

This invention relates to the preparation and application of small-molecule donor materials for organic solar cells. The small-molecule donor materials ZMH-1 and ZMH-2 are BODIPY derivatives of 2,4,6-trimethylphenyl at the meso position, covalently linked, and obtained by Knoevenagel condensation reactions with 4-diphenylaminobenzaldehyde and N-n-butyl-3-carbazole aldehyde, respectively. These two small-molecule donor materials possess the same low HOMO energy level and narrow bandgap, excellent solubility, and large Stokes shift, exhibiting strong absorption in the near-infrared region. The small-molecule donor materials provided by this invention possess suitable energy levels and spectral absorption, and can interact with acceptor materials such as PC. 71 BM and IDT-TC form good absorption complementarity and energy level matching; they are used as electron donor materials for the active layer in the fabrication of organic solar cells. Under optimized conditions, the active layer is ZMH-1:PC. 71 BM∶IDT-TC or ZMH-2∶PC 71 BM: IDT-TC's cells achieved photoelectric conversion efficiencies of 13.70% and 12.71% respectively, demonstrating certain practical application value and prospects.

Description

Technical Field

[0001] This invention belongs to the fields of organic compound synthesis, organic solar energy, and fine chemical technology, and specifically relates to the preparation and application of a small molecule donor material for solar cells. Background Technology

[0002] With the depletion of fossil fuels and the increasing severity of environmental pollution, green and sustainable energy has become a new hope. Among numerous new energy sources, organic solar cells have attracted much attention due to their advantages such as low cost, light weight, ease of processing, and low pollution. Bulk heterojunction (BHJ) organic solar cells are formed by mixing electron acceptor materials with electron-donating polymers or small molecules, achieving a photoelectric conversion efficiency exceeding 10%. Currently, the active layer of high-efficiency organic solar cells consists of polymer donors and small-molecule non-fullerene acceptors. However, the polydispersity of the intrinsic molecular weight of polymers leads to batch-to-batch variability, causing differences in photoelectric conversion efficiency (PCE), which is detrimental to mass production. In contrast, small-molecule organic solar cells have received widespread attention due to their well-defined chemical structures, good reproducibility, and small batch-to-batch variability. Therefore, molecular design work using small molecules as donor materials is crucial.

[0003] From a chemical structure perspective, molecular design strategies for small molecule donors include extending the conjugated core unit and designing end groups, side chains, and π-bridges. By adjusting the end groups of small molecule donors, photoelectric properties can be effectively modulated, and the morphology of blends can be optimized and stabilized.

[0004] In the field of organic solar cells, finding efficient small-molecule donor materials is key to improving photoelectric conversion efficiency. Among them, BODIPY has attracted much attention due to its excellent photoelectric properties. The simple structure and numerous reactive sites of BODIPY facilitate its synthesis and structural modification, providing researchers with more optimization opportunities. Its conjugated planar structure facilitates electron cloud flow and migration. Furthermore, its good solubility allows for excellent dispersibility in various organic solvents, a crucial characteristic in processing and preparation. More importantly, its central framework can be easily modified to meet different needs by introducing functional groups at different α-, β-, or meso substitution positions. The absorption spectra of unmodified BODIPY monomer derivatives are typically in the 500-600 nm range. Due to the small Stokes shift of the monomer, the high overlap between the electronic absorption peak and the fluorescence emission peak limits its practical application. Therefore, researchers are developing structural modifications and improving the properties of BODIPY dimers with large Stokes shifts. By bridging the monomer, the energy gap of the dimer molecule can be reduced, and the spectrum can be significantly red-shifted by increasing the degree of conjugation. In recent years, BODIPY compounds have shown great application potential in the field of small molecule donor materials for organic solar cells. The design and synthesis of high-performance BODIPY compounds are of great significance for the development of new high-efficiency and low-cost organic solar cells.

[0005] This invention relates to the preparation and application of small molecule donors for organic solar cells. The invention combines small molecule donors ZMH-1 and ZMH-2 with electron acceptors IDT-TC and PC. 71 BM has achieved excellent results as an active layer material in organic solar cells, with a photoelectric conversion efficiency of up to 13.70%, and has great application prospects in the field of organic solar cells. Summary of the Invention

[0006] Purpose of the invention: In view of the shortcomings of the existing technology, the purpose of this invention is to provide a class of small molecule donors for organic solar cells, their preparation methods and applications.

[0007] Technical solution: To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0008] The present invention discloses a type of small molecule donor material for organic solar cells, characterized in that the compound has the structural formulas shown in formulas ZMH-1 and ZMH-2:

[0009]

[0010] The method for preparing small molecule donor materials for organic solar cells according to the present invention comprises the following steps:

[0011] 1) Under nitrogen protection, the BODIPY monomer derivative (I) was dissolved in dry dichloromethane, and a ferric chloride nitromethane solution was added dropwise at -78°C. After the addition was completed, the reaction was allowed to proceed for half an hour, and then the temperature was naturally raised to room temperature. The reaction mixture was diluted with dichloromethane and washed with water. The organic layer was dried with anhydrous sodium sulfate, and the solvent was removed by vacuum distillation. The mixture was then purified by silica gel column chromatography with dichloromethane-petroleum ether (v:v = 1:1) as the eluent to obtain compound (II).

[0012] 2) Under anhydrous conditions, compound (II) was reacted with 4-diphenylaminobenzaldehyde or N-n-butyl-3-carbazole aldehyde in a 100 mL double-necked flask. Freshly dried p-toluenesulfonic acid was added, followed by 10 mL of anhydrous toluene for dissolution. 0.2 mL of piperidine was added as a catalyst, and the mixture was heated to reflux for 4–6 hours. After the reaction was completed, the mixture was cooled to room temperature. The mixture was diluted with dichloromethane and washed with water. The organic layer was dried over anhydrous sodium sulfate, and the solvent was removed by vacuum distillation. The mixture was then purified by silica gel column chromatography using dichloromethane-petroleum ether (v:v = 1:1) as the eluent to obtain the small molecule donor materials ZMH-1 and ZMH-2. The specific chemical reaction formulas are shown below:

[0013]

[0014] In step 1) above, the molar ratio of BODIPY monomer derivative (I) to ferric chloride is 1:3.

[0015] In step 2) above, the molar ratio of compound (II), p-toluenesulfonic acid and 4-diphenylaminobenzaldehyde is 1:1:5.0, the molar ratio of compound (II), p-toluenesulfonic acid and N-n-butyl-3-carbazole aldehyde is 1:1:5.0, and the volume-to-molar ratio of toluene, piperidine and compound (I) is 50mL:1mL:1mmol;

[0016] The application of the small molecule donor described in this invention in organic solar cells includes the following steps:

[0017] (1) The ITO glass was ultrasonically cleaned with detergent, deionized water, acetone and isopropanol in succession, and then vacuum dried.

[0018] (2) PEDOT:PSS was spin-coated on ITO glass at a spin speed of 2500 rpm / min to prepare a hole transport layer with a thickness of 35-40 nm.

[0019] (3) According to ZMH-1∶PC 71 BM, ZMH-2: PC 71The electron donor and electron acceptor materials were dissolved together in chloroform solvent at a mass ratio of 1:0.4 to 1:1.4, with a concentration of 16 mg / mL. The solution was then spin-coated onto the hole PEDOT:PSS transport layer at room temperature and under a nitrogen atmosphere at a spin-coating speed of 2500 rpm / min for 60 s to form a bulk heterojunction film. The film was then annealed by solvent vapor exposure in tetrahydrofuran vapor for 40 s.

[0020] (4) Dissolve PFN-Br in methanol solvent and spin-coat it on top of the active layer at a spin-coating speed of 3000 rpm / min for 1 min to form an electron transport layer.

[0021] (5) Under vacuum conditions, metallic aluminum (Al) is thermally evaporated and deposited onto the top of the PFN-Br electron transport layer.

[0022] The organic solar cell of this invention comprises, from bottom to top, a transparent conductive substrate (ITO glass), a hole transport layer (poly(3,4-ethylenedioxythiophene)(PEDOT):poly(styrenesulfonic acid)(PSS)), an organic active layer, an electron transport layer (polyfluorene derivative (PFN-Br)), and a metal electrode (Al). The organic active layer consists of bulk heterojunctions of donor and acceptor ZMH-1:IDT-TC, ZMH-2:IDT-TC, and ZMH-1:PC, respectively. 71 BM∶IDT-TC or ZMH-2∶PC 71 BM∶IDT-TC;

[0023] The active layer contains ZMH-1:IDT-TC, ZMH-2:IDT-TC, and ZMH-1:PC. 71 BM∶IDT-TC or ZMH-2∶PC 71 The mass ratio of BM:IDT-TC is 1:0.2 to 1:1.4, with a preferred ratio of 1:1.2.

[0024] The small molecule donors ZMH-1 and ZMH-2, the non-fullerene acceptor small molecule IDT-TC, and the fullerene acceptor small molecule PC in the organic active layer of this invention 71 The molecular structural formulas of BM are shown below:

[0025]

[0026] Beneficial effects of the present invention

[0027] Compared with the prior art, the small molecule electron donor of the present invention and its application in organic solar cells have the following advantages: (1) The synthesis process of this type of small molecule solar cell electron donor is simple, the reaction conditions are mild, and the selectivity is good, with low production cost; (2) The two donor molecules ZMH-1 and ZMH-2 have long absorption wavelengths, wide absorption ranges and large absorption intensities, and are compatible with IDT-TC and PC. 71 The complementary absorption spectra of BM can broaden the light absorption range of the entire system, which is beneficial to improving the short-circuit current (Jsc) of the device; (3) This type of small molecule solar electron donor has excellent photothermal stability and high open-circuit voltage. These excellent properties make it have great application potential in solar cells; (4) This type of small molecule solar electron donor and acceptor can form good energy level matching and effective charge transfer, which is beneficial to improving the performance of the battery device; (5) The dendritic rigid structure of the double BODIPY acceptor small molecule not only improves the crystallinity of the active layer, but also effectively inhibits the excessive aggregation of the active layer in the film, which is beneficial to forming a suitable phase separation, optimizing the morphology of the active layer, making the system have better stability and better photoelectric conversion performance. The photoelectric conversion efficiency can reach up to 13.70%, which has a good application prospect in the field of solar cells. Attached Figure Description

[0028] Figure 1 The donor materials are ZMH-1 and ZMH-2, and the acceptor materials are IDT-TC and PC. 71 The thin film electron absorption spectrum of BM, where the horizontal axis is wavelength (nm) and the vertical axis is absorbance;

[0029] Figure 2 The donor materials ZMH-1 and ZMH-2, and their respective interactions with acceptor materials IDT-TC and PC. 71 Fluorescence emission spectrum of BM blend thin film, where the horizontal axis is wavelength (nm) and the vertical axis is emission intensity;

[0030] Figure 3 In this invention, donor materials ZMH-1 and ZMH-2 and acceptor materials IDT-TC and PC are used to prepare organic solar cells. 71 The energy level diagram of BM, with the vertical axis representing energy levels and the unit being eV;

[0031] Figure 4 For the application of the small molecule donors of the present invention in organic solar cells, under preferred conditions, the solar cells are based on (a) ZMH-1∶IDT-TC, (b) ZMH-2∶IDT-TC, and (c) ZMH-1∶PC. 71BM∶IDT-TC、(d)ZMH-2∶PC 71 BM: Device current of IDT-TC (J) sc - Voltage (V) oc )picture. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings.

[0033] use 1 The device was characterized and confirmed to possess a donor structure for a small-molecule solar cell by 1H-NMR and MALDI-TOF-MS spectroscopy. The instruments used for analysis were: a Bruker ARX400 NMR spectrometer and a Bruker ARX600 NMR spectrometer (both using deuterated chloroform as solvent); a Shimadzu UV-3100 UV-Vis spectrophotometer (scanning range 300–900 nm, optical path slit 2 nm); and fluorescence spectroscopy was measured using an Amico Bowman Series 2 Luminescence Spectrometer. The photoelectric conversion efficiency was determined using a Keithley 2400 source meter (AM1.5G, 100 mW / cm²). 2 )test.

[0034] Example 1

[0035] Preparation of compound (II)

[0036] Under nitrogen protection, the BODIPY monomer derivative (I) (134 mg, 0.4 mmol) was dissolved in dry dichloromethane (100 mL), and a nitromethane solution of ferric chloride (194 mg, 1.2 mmol) (3.6 mL) was added dropwise at -78 °C. After the addition was completed, the reaction was allowed to proceed for half an hour, and the mixture was allowed to naturally warm to room temperature. The mixture was diluted with dichloromethane and washed with water. The organic layer was dried over anhydrous sodium sulfate, the solvent was removed by vacuum distillation, and then purified by silica gel column chromatography with dichloromethane-petroleum ether (v1:v2 = 1:1) as the eluent to obtain compound (II) (191 mg, 57%). 1 H NMR (400MHz, CDCl3): δ (ppm) 6.92 (s, 4H), 6.48-6.20 (m, 6H), 2.64 (s, 6H), 2.52 (s, 6H), 2.34 (s, 6H), 2.11 (s, 12H).

[0037] Example 2

[0038] Preparation of compound ZMH-1

[0039] Under anhydrous conditions, compound (II) (33.7 mg, 0.05 mmol) and 4-diphenylaminobenzaldehyde (68 mg, 0.25 mmol) were placed in a 100 mL double-necked reaction flask. Freshly dried p-toluenesulfonic acid (10 mg, 0.05 mmol) was added, followed by the addition of anhydrous toluene (10 mL) to dissolve the mixture. Piperidine (0.2 mL) was added as a catalyst, and the mixture was heated to reflux for 4–6 hours. After the reaction was completed, the mixture was cooled to room temperature, diluted with dichloromethane, washed with water, dried over anhydrous sodium sulfate, and purified by silica gel column chromatography after the solvent was evaporated under reduced pressure. The eluent was dichloromethane-petroleum ether (v1:v2 = 1:1) to obtain the small molecule donor material ZMH-1 (58 mg, 69%). 1 H NMR (600MHz, CDCl3): δ (ppm) 7.64-7.57 (m, 4H), 7.47 (d, J=9Hz, 4H), 7.30-7 .27(m, 10H), 7.24-7.23(m, 10H), 7.14(d, J=7.8Hz, 8H), 7.10-7.06(m, 14H), 7.04-7.02 (m, 10H), 6.93 (d, J = 8.4Hz, 4H), 6.88 (s, 4H), 6.85 (d, J = 4.2Hz, 2H ), 6.52(d, J=4.2Hz, 2H), 6.42(s, 2H), 2.31(s, 6H), 2.10(s, 12H).MADLI-TOF MS:C 116 H 92 B2F4N8calculated for: 1675.758; found: 1675.634[M] + .

[0040] Example 3

[0041] Preparation of compound ZMH-2

[0042] Under anhydrous conditions, compound (II) (50 mg, 0.074 mmol) and N-n-butyl-3-carbazole aldehyde (93 mg, 0.37 mmol) were placed in a 100 mL double-necked reaction flask, and freshly dried p-toluenesulfonic acid (13 mg, 0.074 mmol) was added. The mixture was fitted with a Dean-Stark apparatus, and then anhydrous toluene (10 mL) was added to dissolve the compound. Piperidine (0.2 mL) was added as a catalyst, and the mixture was stirred and heated to reflux for 4–6 hours. After the reaction was completed, the mixture was cooled to room temperature, diluted with dichloromethane, washed with water, dried over anhydrous sodium sulfate, and purified by silica gel column chromatography after the solvent was evaporated under reduced pressure. The eluent was dichloromethane-petroleum ether (v1:v2 = 1:1) to obtain the small molecule donor material ZMH-2 (80 mg, 67%). 1H NMR (600MHz, CDCl3): δ (ppm) 8.38 (s, 2H), 8.22-8.20 (m, 4H), 8.15 (d, J=7.8Hz, 2H), 7.95-7.85 (m, 6H), 7.6 4-7.62(m, 4H), 7.53-7.50(m, 4H), 7.47-7.43(m, 6H), 7.38-7.33(m, 4H), 7.30-7.28(m, 2H), 7.23-7.20(m, 2H), 6.99-6.98 (m, 2H), 6.86 (s, 4H), 6.60 (d, J=4.8Hz, 2H), 6.56 (s, 2H), 4.34 (t, J=7.2Hz, 4H), 4.26 (t, J= 7.2Hz, 4H), 2.28(s, 6H), 2.16(s, 12H), 1.91-1.83(m, 8H), 1.46-1.42(m, 4H), 1.40-1.36(m, 4H).MADLI-TOF MS:C 108 H 100 B2F4N8calculated for: 1587.821; found: 1587.674[M] + .

[0043] Example 4

[0044] Small molecule donor materials ZMH-1 and ZMH-2 and acceptor materials IDT-TC and PC for solar cells 71 BM thin film electronic absorption spectrum

[0045] Compounds ZMH-1, ZMH-2, IDT-TC, and PC 71 BM was dissolved in chloroform solution and spin-coated to prepare thin films, and the electronic absorption spectra of the thin films were measured.

[0046] Figure 1 ZMH-1 and ZMH-2 are small molecule donor materials for solar cells, and IDT-TC and PC are acceptor materials. 71 BM thin film-electron absorption spectrum.

[0047] Example 5

[0048] Small molecule donor materials ZMH-1 and ZMH-2 for solar cells, and their respective interactions with acceptor materials IDT-TC and PC. 71 Fluorescence emission spectra of BM blend thin films

[0049] Compounds ZMH-1, ZMH-1∶IDT-TC, and ZMH-1∶PC were used. 71 BM, ZMH-2, ZMH-2:IDT-TC, ZMH-2:PC71 BM was dissolved in chloroform solution and spin-coated to prepare thin films, and the fluorescence emission spectra of the thin films were measured.

[0050] Figure 2 ZMH-1 and ZMH-2 are small molecule donor materials for solar cells, and their respective acceptor materials IDT-TC and PC are used for solar cells. 71 Fluorescence emission spectrum of BM blend thin film.

[0051] Example 6

[0052] Fabrication of organic solar cell devices

[0053] The battery device is constructed using indium tin oxide (ITO) / PEDOT:PSS / active layer / PFN-Br / Al. ITO is the indium tin oxide conductive glass substrate; poly(3,4-ethylenedichlorothiophene):poly(styrene sulfonate) (PEDOT:PSS) is the hole transport layer (HTL); the active layer consists of donors ZMH-1 and ZMH-2 and acceptors PC... 71 A binary active layer consisting of BM, IDT-TC, and PC 71 The ternary active layer is composed of a blend of BM and IDT-TC, with poly[(9,9-bis(3-(N,N-dimethylamino)propyl leuco)-2,7-)-alt-2,7-(9,9-dioctyl leuco) (PFN)]-Br as the electron transport layer (ETL) and Al as the cathode.

[0054] PEDOT:PSS was spin-coated onto ITO glass that had been ultrasonically cleaned with detergent, deionized water, acetone, and isopropanol and then vacuum-dried at a spin-coating speed of 2500 rpm / min to prepare a hole transport layer with a thickness of 35–40 nm. A chloroform solution of the active layer was prepared with electron donors and acceptors in ZMH-1:IDT-TC mass ratios of 1:0.2, 1:0.4, 1:0.8, 1:1.2, and 1:1.4, respectively, at a concentration of 16 mg / mL. This solution was then spin-coated onto the hole transport layer PEDOT:PSS at room temperature and under a nitrogen atmosphere. On the S transport layer, a bulk heterojunction film is formed by spin coating at a speed of 2500 rpm / min for 60 s. Then, it is treated by solvent vapor annealing (SVA) and exposed to tetrahydrofuran vapor for 40 s. PFN-Br is then dissolved in methanol solvent and spin-coated onto the active layer of the bulk heterojunction to form the PFN-Br electron transport layer at a speed of 3000 rpm / min for 60 s. Finally, aluminum (Al) is deposited on top of the PFN layer by thermal evaporation under vacuum conditions.

[0055] Example 7

[0056] PEDOT:PSS was spin-coated onto ITO glass that had been ultrasonically cleaned with detergent, deionized water, acetone, and isopropanol and then vacuum-dried at a spin-coating speed of 2500 rpm / min to prepare a hole transport layer with a thickness of 35–40 nm. An active layer chloroform solution with a concentration of 16 mg / mL was prepared by spin-coating electron donors and acceptors at ZMH-2:IDT-TC mass ratios of 1:0.2, 1:0.4, 1:0.8, 1:1.2, and 1:1.4, respectively. This solution was then spin-coated onto the hole transport layer PEDOT:PSS at room temperature and under a nitrogen atmosphere. On the S transport layer, a bulk heterojunction film is formed by spin coating at a speed of 2500 rpm / min for 60 s. Then, it is treated by solvent vapor annealing (SVA) and exposed to tetrahydrofuran vapor for 40 s. PFN-Br is then dissolved in methanol solvent and spin-coated onto the active layer of the bulk heterojunction to form the PFN-Br electron transport layer at a speed of 3000 rpm / min for 60 s. Finally, aluminum (Al) is deposited on top of the PFN layer by thermal evaporation under vacuum conditions.

[0057] Example 8

[0058] PEDOT:PSS was spin-coated onto ITO glass that had been ultrasonically cleaned with detergent, deionized water, acetone, and isopropanol and then vacuum-dried to prepare a hole transport layer with a thickness of 35–40 nm. The spin-coating speed was 2500 rpm / min. Electron donors and acceptors were then arranged according to the ZMH-1:PC ratio described above. 71 A chloroform solution with a concentration of 16 mg / mL was prepared by mixing BM and IDT-TC at mass ratios of 1:0.2:1, 1:0.4:0.8, and 1:0.6:0.6. This solution was then spin-coated onto the hole PEDOT:PSS transport layer at room temperature and under a nitrogen atmosphere at a spin-coating speed of 2500 rpm / min for 60 s to form a bulk heterojunction film. The film was then treated with solvent vapor annealing (SVA) by exposing the film to tetrahydrofuran vapor for 40 s. Next, PFN-Br was dissolved in methanol and spin-coated onto the bulk heterojunction active layer to form the PFN-Br electron transport layer at a spin-coating speed of 3000 rpm / min for 60 s. Finally, aluminum (Al) was deposited onto the top of the PFN layer by thermal evaporation under vacuum conditions.

[0059] Example 9

[0060] PEDOT:PSS was spin-coated onto ITO glass that had been ultrasonically cleaned with detergent, deionized water, acetone, and isopropanol and then vacuum-dried to prepare a hole transport layer with a thickness of 35–40 nm. The spin-coating speed was 2500 rpm / min. Electron donors and acceptors were then arranged according to the ZMH-2:PC ratio described above. 71 Chloroform solutions of the active layer with a concentration of 16 mg / mL were prepared at BM:IDT-TC mass ratios of 1:0.2:1, 1:0.4:0.8, and 1:0.6:0.6. These solutions were then spin-coated onto the hole PEDOT:PSS transport layer at room temperature and under a nitrogen atmosphere at a spin-coating speed of 2500 rpm / min for 60 s to form a bulk heterojunction film. The film was then treated with solvent vapor annealing (SVA) by exposing it to tetrahydrofuran vapor for 40 s. Next, PFN-Br was dissolved in methanol and spin-coated onto the active layer of the bulk heterojunction to form the PFN-Br electron transport layer at a spin-coating speed of 3000 rpm / min for 60 s. Finally, aluminum (Al) was deposited onto the top of the PFN layer under vacuum conditions via thermal evaporation.

[0061] Example 10

[0062] In this invention, ZMH-1 and ZMH-2 are used as donor materials for solar cells and PC is used as the donor material. 71 Organic solar cells were fabricated using BM and IDT-TC as solar cell acceptors. The binary blended active layers were ZMH-1:IDT-TC (mass ratio 1:1.2) and ZMH-2:IDT-TC (mass ratio 1:1.2), respectively, and the ternary blended active layers were ZMH-1:PC. 71 BM∶IDT-TC (mass ratio 1∶0.4∶0.8), ZMH-2∶PC 71 BM∶IDT-TC (mass ratio 1∶0.4∶0.8). The photoelectric conversion efficiency current-voltage curves of the devices are shown below. Figure 4 The performance of the above devices is summarized in the table below:

[0063]

Claims

1. A class of small-molecule donor materials for organic solar cells, characterized in that, Its structural formula is shown below:

2. The method for preparing a type of small molecule donor material for organic solar cells according to claim 1, characterized in that, The preparation method is as follows: BODIPY derivative (I) is reacted with FeCl3 to generate a covalently linked bis-BODIPY derivative (II), which is then reacted with 4-diphenylaminobenzaldehyde and N-n-butyl-3-carbazole aldehyde via Knoe-Venagel condensation reactions to obtain small molecule donor materials ZMH-1 and ZMH-2, respectively. The reaction formulas for this preparation process are as follows:

3. The method for preparing the organic solar cell small molecule donor materials ZMH-1 and ZMH-2 according to claim 2, characterized in that, The feature method includes the following steps: 1) Under nitrogen protection, the BODIPY monomer derivative (I) was dissolved in dry dichloromethane, and a ferric chloride nitromethane solution was added dropwise at -78°C. After the addition was completed, the reaction was carried out for half an hour, and then the mixture was brought to room temperature. The mixture was extracted with dichloromethane, and the organic layer was dried with anhydrous sodium sulfate, the solvent was removed by vacuum evaporation, and then purified by silica gel column chromatography. The eluent was dichloromethane-petroleum ether v:V = 1:1, to obtain the coupled bisBODIPY compound (II). 2) Under anhydrous conditions, compound (II) was placed in a 100 mL double-necked reaction flask with 4-diphenylaminobenzaldehyde or N-n-butyl-3-carbazole aldehyde, respectively. Freshly dried p-toluenesulfonic acid was added, followed by 10 mL of anhydrous toluene for dissolution. 0.2 mL of piperidine was added as a catalyst, and the mixture was stirred and heated to reflux for 4–6 hours. After the reaction was completed, the mixture was cooled to room temperature. The mixture was diluted with dichloromethane, washed with water, and the organic layer was dried with anhydrous sodium sulfate. After the solvent was evaporated under reduced pressure, the mixture was purified by silica gel column chromatography with dichloromethane-petroleum ether v:v = 1:1 as the eluent to obtain small molecule donor materials ZMH-1 and ZMH-2.

4. The preparation method of the two small molecule donor materials ZMH-1 and ZMH-2 for organic solar cells according to claim 3, characterized in that... In step 1), the molar ratio of BODIPY monomer derivative (I) to ferric chloride is 1:

3.

5. The method for preparing the two small molecule donor materials for organic solar cells according to claim 3, characterized in that... In step 2), the molar ratio of compound (II), p-toluenesulfonic acid and 4-diphenylaminobenzaldehyde is 1:1:5; the molar ratio of compound (II), p-toluenesulfonic acid and N-n-butyl-3-carbazole aldehyde is 1:1:5; and the volume-to-molar ratio of toluene, piperidine and compound (I) is 50mL:1mL:1mmol.

6. The application of small molecule donor materials in organic solar cells, characterized in that, Organic solar cell devices are manufactured using an indium tin oxide (ITO) / polyethoxythiophene (PEDOT): polystyrene sulfonic acid (PSS) / active layer / polyphosphorus derivative (PFN)-Br / Al structure; the active layer includes a donor material and an acceptor material, wherein the donor material is the small molecule donors ZMH-1 and ZMH-2 as described in claim 1.

7. The organic solar cell according to claim 6, characterized in that, The receptor material is PC 71 One or both of BM and IDT-TC, wherein the binary active layer is ZMH-1:IDT-TC, ZMH-2:IDT-TC, and the ternary active layer is ZMH-1:PC. 71 BM: IDT-TC, ZMH-2: PC 71 BM: IDT-TC.

8. The organic solar cell according to claim 6, characterized in that, The optimal photovoltaic performance of the binary active layer blending ratio for the battery is ZMH-1:IDT-TC = 1:1.2 and ZMH-2:IDT-TC = 1:1.2, achieving photoelectric conversion efficiencies of 11.28% and 5.48%, respectively. The optimal photovoltaic performance of the ternary active layer blending ratio for the battery is ZMH-1:PC. 71 BM: IDT-TC=1:0.4:0.8, ZMH-2: PC 71 With a BM:IDT-TC ratio of 1:0.4:0.8, the photoelectric conversion efficiency can reach 13.70% and 12.71%.

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