A dimer non-fullerene acceptor molecule based on a pyranone-ring-locked structure, its preparation and application as an acceptor photovoltaic material.

Abstract

This invention relates to a pyranone-ring-locked dimer non-fullerene acceptor molecule, its preparation, and its application as an acceptor photovoltaic material, belonging to the field of organic solar cell materials technology. Based on the pyranone structure, an A-D-A'-D-A type dimer non-fullerene acceptor molecule was designed and synthesized, where A is an electron-withdrawing unit, D is an electron-donating unit, and A' is an electron-withdrawing unit based on the pyranone structure. The dimer molecule has the general structural formula of Formula I. Wherein, EG is selected from conjugated groups with electron-withdrawing ability, Ar is selected from conjugated groups with electron-donating ability, and X is selected from hydrogen atoms or halogens. The dimer acceptor molecule exhibits a small dihedral angle, which is beneficial for intermolecular stacking, resulting in high carrier mobility. The dimer acceptor molecule with the pyranone structure exhibits significantly improved stability under light and nucleophilic attack, and its organic solar cell device exhibits good photoelectric conversion efficiency.

Description

Technical Field

[0001] This invention belongs to the field of organic solar cell materials technology, and relates to the preparation of photovoltaic materials, particularly to a dimer non-fullerene acceptor molecule based on a pyranone-ring-locked structure, its preparation, and its application as an acceptor photovoltaic material. Background Technology

[0002] In recent years, organic solar cells (OSCs) have attracted widespread attention. Compared to inorganic solar cells, OSCs offer advantages such as solution processability, light weight, good flexibility, and the ability to be mass-produced using low-cost solutions through roll-to-roll coating and printing techniques. Currently, thanks to the synergistic development of new material design and device fabrication processes, the power conversion efficiency (PCE) of OSCs based on acceptor-donor-acceptor (ADA) type non-fullerene acceptors (NFAs) has exceeded 20%, comparable to commercial silicon-based solar cells, demonstrating their enormous application potential. However, the stability of OSCs remains a challenge in this field.

[0003] In typical ADA-type NFAs, such as the ITIC series, Y series, and non-fused-ring series, a common structural feature is the presence of two exocyclic ethylene bridges formed by Knoevenagel condensation at the junction of the D and A units. This structural design results in a strong push-pull electron effect, making these exocyclic ethylene bridges highly reactive. These ethylene bridges are not only susceptible to attack by nucleophiles at the interface layer but also prone to photo-oxidation in oxygen environments or six-electron electrocyclic reactions in inert atmospheres, all of which can lead to NFA degradation during device operation. Therefore, improving the intrinsic chemical and photochemical stability of NFAs at the molecular level remains a significant challenge in this field. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention solves the technical problem that organic solar cell acceptor materials are prone to degradation under light and nucleophilic reagent environments. By introducing a pyranone-ring-lock structure, the resulting dimer acceptor photovoltaic material has technical advantages such as high photostability and chemical stability, and organic solar cell devices based on this acceptor material exhibit high light and thermal stability.

[0005] According to a first aspect of the present invention, an AD-A'-DA type dimer nonfullerene acceptor molecule based on a pyranone-ring-locked structure is provided, wherein the AD-A'-DA type dimer nonfullerene acceptor molecule has the structural formula shown in Formula I: wherein A is an electron-withdrawing unit, D is an electron-donating unit, and A' is an electron-withdrawing unit based on a pyranone structure.

[0006]

[0007] in:

[0008] EG is selected from conjugated groups with electron-withdrawing capabilities;

[0009] Ar is selected from electron-rich conjugated aromatic structures;

[0010] X is selected from hydrogen atoms or halogens.

[0011] Preferably, EG is selected from one of the following structures:

[0012]

[0013] Where Y is any one of hydrogen atoms or halogens, and the dashed line indicates the connection position between EG and Ar.

[0014] Preferably, Ar is selected from one of the following structures:

[0015]

[0016] Where R1 is a hydrogen atom, C1-C 30 Alkyl, C1-C 30 Any one of the alkoxy groups; R2 is a hydrogen atom, C1-C 30 Alkyl, C1-C 30 Any of the alkoxy groups; the dashed lines indicate the connection points between Ar and the electron-withdrawing units at both ends.

[0017] According to another aspect of the present invention, a method for synthesizing the AD-A'-DA type dimer non-fullerene acceptor molecule based on the pyranone-ring-locked structure is provided, comprising the following steps:

[0018] (1) Compound 1 and 2,6-dimethyl-4H-pyranone were dissolved in acetic anhydride and reacted under heating conditions; after the reaction was complete, the reaction solution was extracted, the solvent was removed, and the solution was purified to obtain compound 2.

[0019]

[0020] Where X is any one of hydrogen atoms or halogens;

[0021] (2) Under the protection of nitrogen or an inert gas, compound 2, compound 3 and piperidine are dissolved in organic solvent A and reacted at 70-140°C; the organic solvent A is chloroform, toluene or xylene; after the reaction is complete, the reaction solution is extracted, the solvent is removed and purified to obtain compound 4;

[0022]

[0023] (3) Under the protection of nitrogen or an inert gas, compound 4, compound 5, boron trifluoride in ether solution and acetic anhydride are dissolved in organic solvent B, wherein organic solvent B is dry chloroform, toluene or xylene; the reaction is carried out at 0-60℃; after the reaction is complete, the reaction solution is extracted, the solvent is removed and purified to obtain AD-A'-DA type dimer nonfullerene acceptor molecular formula I based on pyranone structure;

[0024]

[0025] Where Y is either a hydrogen atom or a halogen.

[0026] Preferably, Ar in compounds 3 and 4 is selected from one of the following structures:

[0027]

[0028] Where R1 is a hydrogen atom, C1-C 30 Alkyl, C1-C 30 Any of the alkoxy groups, where R2 is a hydrogen atom, C1-C 30 Alkyl, C1-C 30 Any of the alkoxy groups; the dashed lines indicate the connection points between Ar and the electron-withdrawing units at both ends.

[0029] Preferably, in step (1), the molar ratio of compound 1 to 2,6-dimethyl-4H-pyranone is 1:(1-4); the concentration of compound 1 in acetic anhydride is 8 mg / mL to 12 mg / mL; and the reaction time is 8-24 h.

[0030] Preferably, in step (2), the molar ratio of compound 2 to compound 3 is 1:(2-4); the concentration of compound 2 in organic solvent A is 1 mg / mL to 25 mg / mL; and the reaction time is 12-24 h.

[0031] Preferably, in step (3), the molar ratio of compound 4, compound 5, boron trifluoride and acetic anhydride is 1:(2.1-3):(0.05-1):(0.05-1); the concentration of compound 4 in organic solvent B is 0.01 mg / mL to 6 mg / mL; and the reaction time is 0.5 to 12 h.

[0032] According to another aspect of the present invention, the application of the AD-A'-DA type dimer nonfullerene acceptor molecule based on the pyranone-ring-locked structure is provided in the preparation of photovoltaic acceptor materials.

[0033] According to another aspect of the present invention, the application of the AD-A'-DA type dimer nonfullerene acceptor molecule based on the pyranone-ring-locked structure is provided in the preparation of organic solar cell binary devices or organic solar cell ternary devices.

[0034] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages:

[0035] (1) The electron-withdrawing unit (compound 2) based on the pyranone structure prepared in this invention has strong planarity and its crystals have a relatively tight and regular stacking, which is conducive to its formation of good π-π stacking in the acceptor molecule.

[0036] (2) The AD-A'-DA type dimer non-fullerene acceptor molecule based on the pyranone structure prepared in this invention has excellent thermal stability, good energy level, and broad and strong absorption spectrum, which makes the dimer material feasible as a photovoltaic acceptor material and provides a choice for future oligomer materials as active layer materials for binary and ternary devices.

[0037] (3) The AD-A'-DA type dimer nonfullerene acceptor molecule based on the pyranone structure prepared in this invention has strong molecular planarity and can form effective π-π stacking in organic solar cell devices, which is beneficial to the transport of charge carriers.

[0038] (4) The AD-A'-DA type dimer nonfullerene acceptor molecule based on the pyranone structure prepared in this invention has good intrinsic stability. It shows significantly improved stability under strong light irradiation and nucleophilic reagent environment, which is beneficial to improving the stability of organic solar cell devices.

[0039] (5) The organic solar cell device constructed by the AD-A'-DA type dimer nonfullerene acceptor molecule based on the pyranone structure prepared in this invention has excellent external quantum efficiency and considerable photoelectric conversion efficiency. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the synthetic route for the preparation method of ITBIC-F in this invention.

[0041] Figure 2 This is a schematic diagram of the synthetic route for the preparation method of TBTBIC-F of the present invention.

[0042] Figure 3 This is the proton NMR spectrum of the compound ITBIC-F of this invention.

[0043] Figure 4 This is the proton NMR spectrum of the compound TBTBIC-F of this invention.

[0044] Figure 5 This is the UV-Vis absorption spectrum of the pyranone-ring-locked dimeric receptor of the present invention.

[0045] Figure 6 The molecular structure diagram (top view and side view) of the pyranone-ring-locked dimeric receptor of the present invention optimized by DFT.

[0046] Figure 7 This diagram illustrates the improved stability of the pyranone-ring-locked dimeric acceptor under light and nucleophilic reagent conditions. a) Under light, b) Under nucleophilic reagent conditions.

[0047] Figure 8 The current-voltage curve of an organic solar cell made of PM6 using a pyranone-ring-locked dimeric acceptor material provided in the example.

[0048] Figure 9 The external quantum efficiency curve of an organic solar cell made of PM6 with a pyranone-ring-locked dimeric acceptor material provided in the example. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0050] In a first aspect, the present invention provides an AD-A'-DA type dimer non-fullerene acceptor molecule based on a pyranone structure, wherein A is an electron-withdrawing unit, D is an electron-donating unit, and A' is an electron-withdrawing unit based on a pyranone structure. The structural formula of the AD-A'-DA type dimer non-fullerene acceptor molecule is shown in Formula I:

[0051]

[0052] in:

[0053] EG is selected from conjugated groups with electron-withdrawing capabilities;

[0054] Ar is selected from electron-rich conjugated aromatic structures;

[0055] X is selected from hydrogen atoms or halogens.

[0056] In some embodiments, EG is selected from one of the following structures:

[0057]

[0058] Where Y is any one of hydrogen atoms or halogens, and the dashed line indicates the connection position between EG and Ar.

[0059] In some embodiments, Ar is selected from one of the following structures:

[0060]

[0061] Where R1 is a hydrogen atom, C1-C 30 Alkyl, C1-C 30 Any of the alkoxy groups, where R2 is a hydrogen atom, C1-C 30 Alkyl, C1-C 30 Any of the alkoxy groups, with the dashed lines indicating the connection points between Ar and the electron-withdrawing units at both ends.

[0062] Secondly, the method for synthesizing and preparing AD-A'-DA type dimer non-fullerene acceptor molecules based on pyranone structures provided by the present invention includes the following steps:

[0063] (1) Compound 1 and 2,6-dimethyl-4H-pyranone were dissolved in acetic anhydride and reacted under heating conditions; after the reaction was complete, the reaction solution was extracted, the solvent was removed, and the solution was purified to obtain compound 2.

[0064]

[0065] Where X is any one of hydrogen atoms or halogens;

[0066] (2) Under the protection of nitrogen or an inert gas, compound 2, compound 3 and piperidine are dissolved in organic solvent A and reacted at 70-140°C; the organic solvent A is chloroform, toluene or xylene; after the reaction is complete, the reaction solution is extracted, the solvent is removed and purified to obtain compound 4;

[0067]

[0068] (3) Under the protection of nitrogen or an inert gas, compound 4, compound 5, boron trifluoride in ether solution and acetic anhydride are dissolved in organic solvent B, wherein organic solvent B is dry chloroform, toluene or xylene; the reaction is carried out at 0-60℃; after the reaction is complete, the reaction solution is extracted, the solvent is removed and purified to obtain AD-A'-DA type dimer nonfullerene acceptor molecular formula I based on pyranone structure;

[0069]

[0070] Where Y is either a hydrogen atom or a halogen.

[0071] Preferably, Ar in compounds 3 and 4 is selected from one of the following structures:

[0072]

[0073] Where R1 is a hydrogen atom, C1-C 30 Alkyl, C1-C 30 Any of the alkoxy groups, where R2 is a hydrogen atom, C1-C 30 Alkyl, C1-C 30 Any of the alkoxy groups, with the dashed lines indicating the connection points between Ar and the electron-withdrawing units at both ends.

[0074] Preferably, in step (1), the molar ratio of compound 1 to 2,6-dimethyl-4H-pyranone is 1:1 to 1:4; the concentration of compound 1 in acetic anhydride is 8 mg / mL to 12 mg / mL; and the reaction time is 8-24 h.

[0075] Preferably, in step (2), the molar ratio of compound 2 to compound 3 is 1:2 to 1:4; the concentration of compound 2 in organic solvent A is 1 mg / mL to 25 mg / mL; and the reaction time is 12-24 h.

[0076] Preferably, in step (3), the molar ratio of compound 4, compound 5, boron trifluoride and acetic anhydride is 1:(2.1-3):(0.05-1):(0.05-1); the concentration of compound 4 in organic solvent B is 0.01 mg / mL to 6 mg / mL; and the reaction time is 0.5 to 12 h.

[0077] Thirdly, the present invention also provides a method for testing the stability of organic solar cell acceptor materials. The specific testing method is as follows:

[0078] The stability of each receptor material was reflected by measuring the absorption changes of AD-A'-DA type dimer nonfullerene receptor molecules and control receptor materials based on pyranone structures under light and nucleophilic reagent conditions using ultraviolet-visible absorption spectroscopy.

[0079] Fourthly, the present invention also provides an organic solar cell device based on the aforementioned. The organic solar cell comprises an active layer of electron donor and electron acceptor materials, wherein the acceptor material is the AD-A'-DA type dimer non-fullerene acceptor molecule material with the aforementioned pyranone structure.

[0080] In one specific embodiment of the present invention, the receptor material used as a control is IT-4F.

[0081] The structure of IT-4F is shown below:

[0082]

[0083] In one specific embodiment of the present invention, the donor material is PM6.

[0084] The structure of PM6 is shown below:

[0085]

[0086] Example 1: Preparation of pyranone-ring-locked dimer receptor ITBIC-F

[0087] The specific synthesis route is attached. Figure 1 As shown, the specific steps are as follows:

[0088] (1) Synthesis of compound 2:

[0089] Compound 1 (300 mg, 1.3 mmol) and 2,6-dimethyl-4H-pyran-4-one (458 mg, 3.7 mmol) were dissolved in acetic anhydride (40 mL) and refluxed overnight at 130 °C. The reaction progress was monitored by thin-layer chromatography. After complete reaction, the reaction solution was extracted with water and dichloromethane, dried over anhydrous sodium sulfate, and the solvent was removed under vacuum. The residue was purified by silica gel chromatography using dichloromethane as the eluent to obtain the crude product. The crude product was purified by recrystallization from dichloromethane and petroleum ether, and then reprecipitated with diethyl ether to obtain compound 2 as an orange solid (337 mg, 77%). 1 H NMR (600MHz, CDCl3): δ (ppm) 8.32 (broad, 1.7H, ArH), 7.53 (t, J = 7.8Hz, 1H, ArH), 6.59 (broad, 0.7H, ArH), 2.53 (s, 6H, Ar-CH3). 13 C NMR (151MHz, CDCl3) δ185.92,166.08,162.26,154.27,152.56,149.41,136.67,13 3.90,115.53,115.05,113.87,113.73,112.01,111.89,109.90,65.60,20.67.HRMS m / z:[M+H] + Theoretical value C 19 H 10 F2N2O2, 337.0710, measured value: 337.0794.

[0090] (2) Synthesis of compound 4-1:

[0091] Under nitrogen protection, compound 2 (80 mg, 0.24 mmol) and compound 3-1 (511 mg, 0.48 mmol) were dissolved in 20 mL of dry chloroform. The mixture was heated to 70 °C, and then 0.1 mL of piperidine was added dropwise. The solution was stirred overnight at 70 °C, and the reaction progress was monitored by thin-layer chromatography. After the reaction was complete, the reaction solution was extracted with water and dichloromethane, dried over anhydrous sodium sulfate, and the solvent was removed under vacuum. The solution was purified by silica gel chromatography using dichloromethane:petroleum ether:ethyl acetate = 4:1:0.05 as the eluent to give compound 4-1 as a black solid (180 mg, 30%). 1 H NMR (600MHz, CDCl3): δ (ppm) 9.89 (s, 1H, Ar-CHO), 8.33 (dd, J = 9.6, 6.6Hz, 1H, = CH-) ,7.94(s,2H,ArH),7.68(d,J=15.6Hz,2H,=CH-),7.60(d,J=11.4Hz,4H,ArH),7.53( m,3H,ArH),7.15(m,32H,ArH),6.66(d,J=15.0Hz,2H,=CH-),2.58(m,16H,-CH2-),1 .61(m,16H,-CH2-),1.34(m,16H,-CH2-),1.29(m,32H,-CH2-),0.87(m,24H,-CH3).

[0092] (3) Synthesis of ITBIC-F:

[0093] Under N2 protection, compound 4-1 (140 mg, 0.057 mmol) and compound 5 (28 mg, 0.12 mmol) were dissolved in 15 mL of dry toluene. The mixture was heated to 60 °C, and 0.1 mL of acetic anhydride and 0.1 mL of boron trifluoride in diethyl ether (48% BF3) were added dropwise. After heating for 30 min, the reaction solution was extracted with water and dichloromethane, dried over anhydrous sodium sulfate, and the solvent was removed under vacuum. The solution was purified by silica gel chromatography using dichloromethane:petroleum ether = 2:1 as the eluent, and recrystallized from dichloromethane / methanol to give ITBIC-F as a black solid (145 mg, 88%). 1H NMR (400MHz, CDCl3): δ (ppm) 8.85 (s, 2H, = CH-), 8.53 (dd, J = 9.6, 6.4Hz, 2H, ArH), 8.34 (dd, J = 9.6, 6.4Hz, 1H, ArH), 8.23 ​​(s, 2H, ArH), 7.67 (m, 6H, = CH- + ArH ),7.56(m,5H,ArH),7.18(m,32H,ArH),6.67(d,J=15.6Hz,2H,=CH-),2.58(m ,16H,-CH2-),1.61(m,16H,-CH2-),1.32(m,48H,-CH2-),0.87(m,24H,-CH3). 13 C NMR (151MHz, CDCl3) δ186.08,185.93,160.32,158.43,155.90,154.71,154.54,148.13,147.71,147.18,1 46.90,143.77,143.52,142.64,142.58,142.44,139.38,139.26,139.15,138.58,138.21,136.27,135.65 ,131.71,128.98,128.93,128.02,124.92,121.55,118.74,117.81,117.56,114.45,114.35,111.36,69.6 9,63.34,63.16,35.75,31.84,31.83,31.42,31.40,29.33,29.32,22.73,14.23.MS(MALDI-TOF)m / z:[M+H] + Theoretical value C 183 H 158 F6N6O4S8, 2875.00, measured value: 2875.39. Figure 3 This is the proton NMR spectrum of the product prepared in this embodiment.

[0094] Example 2: Preparation of pyranone-ring-locked dimer receptor TBTBIC-F

[0095] The specific synthesis route is attached. Figure 2 As shown, the specific steps are as follows:

[0096] (1) Synthesis of compound 4-2:

[0097] Under nitrogen protection, compound 2 (17 mg, 0.05 mmol) and compound 3-2 (100 mg, 0.10 mmol) were dissolved in 20 mL of dry chloroform. The mixture was heated to 70 °C, and then 0.05 mL of piperidine was added dropwise. The solution was stirred overnight at 70 °C, and the reaction progress was monitored by thin-layer chromatography. After the reaction was complete, the reaction solution was extracted with water and dichloromethane, dried over anhydrous sodium sulfate, and the solvent was removed under vacuum. The solution was purified by silica gel chromatography using dichloromethane:petroleum ether:ethyl acetate = 4:1:0.05 as the eluent to give compound 4-2 as a black solid (35 mg, 30%). 1 H NMR (600MHz, CDCl3): δ (ppm) 10.05 (s, 2H, Ar-CHO), 8.35 (dd, J = 9.0, 6.6Hz, 1H, ArH), 7.83 (d ,J=15.0Hz,2H,=CH-),7.54(m,5H,ArH),7.25(m,4H,ArH),6.71(d,J=15.0Hz,2H,=CH-),4.0 4(m,8H,-OCH2-),2.98(m,4H,Ar-CH2-),2.82(m,4H,Ar-CH2-),1.93(m,4H,-CH-),1.73(m,8 H,-CH2-),1.57(m,8H,-CH2-),1.49(m,8H,-CH2-),1.28(m,120H,-CH2-),0.86(m,36H,CH3).

[0098] (3) Synthesis of TBTBIC-F:

[0099] Under N2 protection, compounds 4-2 (90 mg, 0.039 mmol) and 5 (28 mg, 0.12 mmol) were dissolved in 15 mL of dry toluene. The mixture was heated to 60 °C, and 0.1 mL of acetic anhydride and 0.1 mL of boron trifluoride in diethyl ether (48% BF3) were added dropwise. After heating for 30 min, the reaction solution was extracted with water and dichloromethane, dried over anhydrous sodium sulfate, and the solvent was removed under vacuum. The solution was purified by silica gel chromatography using dichloromethane:petroleum ether = 2:1 as the eluent, and recrystallized from dichloromethane / methanol to give TBTBIC-F as a black solid (105 mg, 99%). 11H NMR (600 MHz, CDCl3): δ (ppm) 9.04 (s, 2H, =CH-), 8.55 (dd, J = 10.2, 6.6 Hz, 2H, ArH), 8.35 (dd, J = 9.6, 6.6 Hz, 1H, ArH), 7.83 (d, J = 15.0 Hz, 2H, =CH-), 7.69 (s, 2H, ArH), 7.66 (t, J = 7.8 Hz, 2H, ArH), 7.60 (s, 2H, ArH), 7.54 (t, J = 7.8 Hz, 1H, ArH), 7.37 (s, 2H, ArH), 7.28 (s, 2H, ArH), 6.72 (d, J = 15.6 Hz, 2H, =CH-), 4.11 (d, J = 4.8 Hz, 8H, -OCH2-), 3.01 (t, J = 7.8 Hz, 4H, Ar-CH2-), 2.84 (t, J = 7.8 Hz, 4H, Ar-CH2-), 2.06 (m, 2H, -CH-), 1.96 (m, 2H, -CH-), 1.74 (m, 8H, -CH2-), 1.60 (m, 16H, -CH2-), 1.33 (m, 120H, -CH2-), 0.86 (m, 36H, -CH3). 13 13C NMR (151 MHz, CDCl3) δ 186.04, 185.62, 161.73, 160.82, 159.53, 155.21, 151.31, 150.30, 148.04, 142.08, 136.53, 135.24, 135.07, 134.83, 132.78, 130.55, 129.97, 129.26, 124.92, 122.54, 120.37, 116.92, 115.85, 115.07, 115.00, 114.94, 114.76, 112.61, 112.38, 112.26, 111.10, 77.37, 72.77, 72.42, 68.90, 64.07, 38.48, 38.43, 32.31, 32.10, 32.09, 32.04, 31.89, 31.87, 31.65, 31.36, 30.45, 30.31, 30.27, 29.96, 29.92, 29.86, 29.82, 29.77, 29.73, 29.64, 29.55, 29.54, 29.41, 29.13, 27.25, 27.21, 27.16, 27.15, 22.86, 22.83, 14.27, 14.26, 14.25, 14.24. MS (MALDI-TOF) m / z: [M+H] + Calculated for C 171 H 222F6N6O8S4, 2731.60, measured value: 2732.05. Figure 4 This is the proton NMR spectrum of the product prepared in this embodiment.

[0100] Example 3: UV-Vis absorption spectroscopy testing of ITBIC-F and TBTBIC-F

[0101] The UV-Vis absorption spectra of ITBIC-F and TBTBIC-F are attached. Figure 5 As shown, the absorption peaks of ITBIC-F and TBTBIC-F in chloroform solution are located at 697 nm and 651 nm, respectively, while the absorption peaks of ITBIC-F and TBTBIC-F films are located at 716 nm and 718 nm, respectively. The absorption spectra of ITBIC-F and TBTBIC-F films show a red shift compared to their absorption spectra in chloroform solution, indicating that there are strong intermolecular interactions in the ITBIC-F and TBTBIC-F films.

[0102] Example 4: Theoretical simulation calculations of ITBIC-F and TBTBIC-F

[0103] We used density functional theory (DFT) to perform theoretical simulations of the molecular conformations of ITBIC-F and TTBTBIC-F. During the calculations, all alkyl chains were simplified to methyl groups, and the B3LYP / 6-31G** algorithm was used for the simulations. The simulation results are attached. Figure 6 As shown, in the top view, ITBIC-F and TBTBIC-F exhibit the same V-shaped geometry; in the side view, both ITBIC-F and TBTBIC-F show strong planarity, which is conducive to the formation of strong π-π stacking between molecules and promotes carrier transport.

[0104] Example 5: Intrinsic stability testing of ITBIC-F and TBTBIC-F

[0105] We investigated the chemical and photochemical stability of ITBIC-F and TBTBIC-F by monitoring the changes in their UV-Vis absorption spectra under external stimuli, and compared them with the star receptor IT-4F as a control compound.

[0106] Photostability test: Take 10 -3 mmol ITBIC-F (2.9 mg) was dissolved in 1.00 mL of tetrahydrofuran to obtain solution A. Then, 50 μL of solution A was taken and diluted to 5.00 mL to obtain 10 mmol / L ITBIC-F. -5 A mol / L ITBIC-F tetrahydrofuran solution. Then take 10... -3 mmol TBTBIC-F (2.7 mg) and IT-4F (1.5 mg) were obtained respectively using the same method described above.-5 A tetrahydrofuran solution of TBTBIC-F and IT-4F at mol / L. The above solutions were tested at 200 mW / cm². -2 The changes in absorption intensity under xenon lamp irradiation are shown in the attached figure. Figure 7 As shown in a) of the figure. After 40 min of illumination, the IT-4F solution retained less than 1% of the initial absorption intensity, while the IT-BIC-F and TBTBIC-F solutions retained 89% and 99% of the initial absorption intensity, respectively.

[0107] Chemical stability test: Take 4.95 mL of 10 -5 Add 50 μL of 10 mol / L tetrahydrofuran solution of ITBIC-F, TTBIC-F, and IT-4F to the solution. -1 A mol / L ethanolamine tetrahydrofuran solution was prepared, and the UV-Vis absorption spectra were measured before addition, after addition, and 1 hour after addition. The test results are attached. Figure 7 As shown in b) of the diagram. For the IT-4F solution, the absorption intensity decreased sharply after the addition of ethanolamine. After stirring for 1 h, the absorption intensities of the ITBIC-F and TBTBIC-F solutions decreased to only 36% and 55% of their initial values, respectively, with little change compared to when ethanolamine was added, while the absorption of the IT-4F solution almost disappeared.

[0108] These results indicate that the photostability and chemical stability of the pyranone-ring-locked dimeric acceptors ITBIC-F and TBTBIC-F are significantly improved.

[0109] Example 6: Fabrication of Organic Solar Cells Based on ITBIC-F and TBTBIC-F

[0110] A solar cell device was fabricated using an ITO / PEDOT:PSS / active layer (PM6:ITBIC-F / TBTBIC-F) / PNDIT-F3N-Br / Ag structure. The fabrication process is as follows:

[0111] Pre-prepared ITO-coated glass substrates were cleaned for 15 minutes each in an ultrasonic bath using methylbenzene, deionized water, acetone, and isopropanol. After drying with high-purity nitrogen, all ITO substrates were cleaned for 15 minutes in a UV-ozone cleaning system. Then, all cleaned ITO glass substrates were placed in a UV-ozone cleaner and irradiated with a UV-ozone lamp for 15 minutes to obtain UV-ozone-treated ITO anodes. Subsequently, a layer of PEDOT:PSS was spin-coated onto the pre-cleaned ITO-coated glass using a PEDOT:PSS aqueous solution at 4000 rpm, annealed at 150°C for 15 minutes, and then the active layer was spin-coated in a glove box. The active layer consisted of a chloroform solution of 16 mg / mL PM6:ITBIC-F or PM6:TBTBIC-F, with mass ratios of PM6:ITBIC-F and PM6:TBTBIC-F of 1:1 and 1:1.2, respectively. The active layer solution was spin-coated at 3500 rpm for 30 seconds, and then annealed at 100°C for 10 minutes. Preferably, the optimal thickness of the active layer is 110 nm. A 1 mg / mL solution was applied to the top of the active layer. -1 The PNDIT-F3N-Br solution was spin-coated at 4000 rpm for 30 seconds to deposit the PNDIT-F3N-Br layer. Finally, the solution was coated with a 5 × 10⁻⁶ solution. -6 Under a vacuum of mbar, the top silver electrode was obtained by thermal evaporation onto the cathode interface layer using a mold. The typical effective area of ​​the studied device is 5 mm². 2 Devices based on PM6:ITBIC-F and PM6:TBTBIC-F achieved photoelectric conversion efficiencies of 13.03% and 10.01%, respectively. Their current density-voltage curves are attached. Figure 8 As shown in the attached figure. The external quantum efficiency spectra of organic solar cells based on ITBIC-F and TBTBIC-F are also shown. Figure 9 As shown, both devices exhibit good optical response across the entire 300-900 nm range. The external quantum efficiency spectral integral current density of the ITBIC-F-based and TTBTBIC-F-based devices are 19.99 mA / cm², respectively. -2 and 17.87mAcm -2 The values ​​match well with the current density-voltage curve.

[0112] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A non-fullerene acceptor molecule of type AD-A'-DA dimer based on a pyranone-ring-locked structure, characterized in that, The structural formula of the AD-A'-DA type dimer non-fullerene acceptor molecule is shown in Formula I: where A is an electron-withdrawing unit, D is an electron-donating unit, and A' is an electron-withdrawing unit based on a pyranone structure. Formula I; in: EG is , where Y is any one of hydrogen atoms or halogens, and the dashed line indicates the connection position between EG and Ar; Ar is selected from one of the following structures: Where R1 is a hydrogen atom, C1-C 30 Alkyl, C1-C 30 Any one of the alkoxy groups; R2 is a hydrogen atom, C1-C 30 Alkyl, C1-C 30 Any of the alkoxy groups; the dashed lines indicate the connection points between Ar and the electron-withdrawing units at both ends; X is selected from hydrogen atoms or halogens.

2. The method for synthesizing the AD-A'-DA type dimer non-fullerene acceptor molecule based on the pyranone-ring-locked structure as described in claim 1, characterized in that, Includes the following steps: (1) Compound 1 and 2,6-dimethyl-4H-pyranone were dissolved in acetic anhydride and reacted under heating conditions; after the reaction was complete, the reaction solution was extracted, the solvent was removed, and the solution was purified to obtain compound 2. Where X is any one of hydrogen atoms or halogens; (2) Under the protection of nitrogen or inert gas, compound 2, compound 3 and piperidine are dissolved in organic solvent A and reacted at 70-140 °C; the organic solvent A is chloroform, toluene or xylene; after the reaction is complete, the reaction solution is extracted to remove the solvent and purified to obtain compound 4; In compounds 3 and 4, Ar is selected from one of the following structures: Where R1 is a hydrogen atom, C1-C 30 Alkyl, C1-C 30 Any one of the alkoxy groups; R2 is a hydrogen atom, C1-C 30 Alkyl, C1-C 30 Any of the alkoxy groups; the dashed lines indicate the connection points between Ar and the electron-withdrawing units at both ends; (3) Under the protection of nitrogen or inert gas, compound 4, compound 5, boron trifluoride in ether solution and acetic anhydride are dissolved in organic solvent B, wherein organic solvent B is dry chloroform, toluene or xylene; the reaction is carried out at 0-60 °C; after the reaction is complete, the reaction solution is extracted, the solvent is removed and purified to obtain AD-A'-DA type dimer nonfullerene acceptor molecular formula I based on pyranone structure; Where EG is Y is any one of hydrogen atoms or halogens.

3. The method for synthesizing the AD-A'-DA type dimer non-fullerene acceptor molecule based on the pyranone-ring-locked structure as described in claim 2, characterized in that, In step (1), the molar ratio of compound 1 to 2,6-dimethyl-4H-pyranone is 1:(1-4); the concentration of compound 1 in acetic anhydride is 8 mg / mL to 12 mg / mL; and the reaction time is 8-24 h.

4. The method for synthesizing the AD-A'-DA type dimer non-fullerene acceptor molecule based on the pyranone-ring-locked structure as described in claim 2, characterized in that, In step (2), the molar ratio of compound 2 to compound 3 is 1:(2-4); the concentration of compound 2 in organic solvent A is 1 mg / mL to 25 mg / mL; and the reaction time is 12-24 h.

5. The method for synthesizing the AD-A'-DA type dimer non-fullerene acceptor molecule based on the pyranone-ring-locked structure as described in claim 2, characterized in that, In step (3), the molar ratio of compound 4, compound 5, boron trifluoride and acetic anhydride is 1:(2.1-3):(0.05-1):(0.05-1); the concentration of compound 4 in organic solvent B is 0.01 mg / mL to 6 mg / mL; and the reaction time is 0.5 to 12 h.

6. The application of the AD-A'-DA type dimer non-fullerene acceptor molecule based on the pyranone-ring-locked structure as described in claim 1 in the preparation of photovoltaic acceptor materials.

7. The application of the AD-A'-DA type dimer non-fullerene acceptor molecule based on the pyranone-ring-locked structure as described in claim 1 in the preparation of organic solar cell binary devices or organic solar cell ternary devices.

Images