Dimer-type acceptor material based on electron-withdrawing bridging unit and preparation method and application thereof

Abstract

The application provides a kind of dimer-type acceptor material based on electron-withdrawing bridging unit and a preparation method and application thereof.The dimer-type acceptor material has a general structure (I) and is constructed by using a benzotriazole unit with electron-withdrawing capacity as a central core and a planar rigid unit with electron-withdrawing capacity as a bridging unit.The acceptor material has a high glass transition temperature and a low diffusion coefficient.The material is used in optoelectronic functional devices, can stabilize the film morphology of the active layer, and finally effectively improves the stability of the device, for example, as an active layer acceptor material of an organic solar cell, which can promote the commercialization of organic solar cells.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic photovoltaics, and particularly relates to a kind of dimer type acceptor material based on electron-withdrawing bridging unit, a preparation method thereof, and application thereof in preparing photoelectric functional devices such as organic solar cells. BACKGROUND

[0002] With the increasing seriousness of environmental pollution, energy crisis and other problems, finding and developing renewable energy has become an important issue for the development of human society. Among many renewable energy sources (such as solar energy, wind energy, tidal energy, geothermal energy, etc.), solar energy has received widespread attention from the industry and academia due to its advantages such as no pollution, wide source, and inexhaustible use, and has made great progress.

[0003] Organic solar cells (OSCs) are currently a popular third-generation photovoltaic technology, which has received widespread attention due to its advantages such as wide source of active layer, light weight, strong processability, and simple manufacturing process (roll-to-roll, printing, spin coating, spraying, etc.). The power conversion efficiency (PCE) of organic solar cells has exceeded 20%, and has broad application prospects. However, the stability problem of current organic solar cells has become a bottleneck for commercial application.

[0004] Dimer acceptor materials have become a strong competitor for small molecule acceptors and polymer acceptors due to their advantages such as clear structure, good batch repeatability, good film-forming property, low diffusion coefficient, and good stability. However, most of the current dimer materials use thiophene, ethylene, acetylene, thiophene-ethylene-thiophene, and thiophene-alkyl chain-thiophene as electron-donating units as bridging units, and their glass transition temperatures are all below 150℃. The low glass transition temperature, high diffusion coefficient, and easy over-aggregation of molecules under thermal stress are not conducive to the morphology stability of the active layer and the long service life of the device. SUMMARY

[0005] The purpose of the present application is to provide a kind of dimer type acceptor material based on electron-withdrawing bridging unit and its preparation method and application, which has a high glass transition temperature and can improve the stability of photoelectric functional devices. The above purpose can be achieved by the following technical solutions:

[0006] The present application provides a kind of dimer type acceptor material based on electron-withdrawing bridging unit, and the structure general formula of the acceptor material is (I):

[0007]

[0008] In the formula (I), Ar is a rigid electron-withdrawing unit with a π conjugated structure; R1, R2 and R3 are linear or branched alkyl groups with 8-25 carbon atoms; X and Y are the same or different hydrogen atoms, F, Cl or Br; and Z is a hydrogen atom, F, Cl or Br.

[0009] Optionally, the Ar structural formula is one of the following formula (II):

[0010]

[0011] In the formula (III), R is a hydrogen atom or a linear or branched alkyl group with 8-25 carbon atoms.

[0012] Optionally, the glass transition temperature of the acceptor material is ≥ 190°C.

[0013] Optionally, the synthesis reaction equation of the acceptor material is the following formula (III):

[0014]

[0015] The application provides a preparation method of a dimer-type acceptor material based on an electron-withdrawing bridging unit, and the preparation method comprises the following steps:

[0016] (1) a dialdehyde-substituted compound (a) and a Br-substituted indenone compound (b) are dissolved in an organic solvent at a molar ratio of 1:0.8-1.2, acetic anhydride and boron trifluoride ether are added, and the mixture is reacted for 30-90 minutes; after the reaction is completed, the organic solvent is spun dry, and column chromatography is performed to separate a single-side precursor compound (c);

[0017] (2) the single-side precursor compound (c) prepared in step (1) and a bistrimethyltin-substituted Ar compound (d) are dissolved in an organic solvent at a molar ratio of 2-2.5:1, a catalyst, a ligand and cuprous iodide are added, and the mixture is reacted at 100-150°C for 12-36 hours under an inert gas atmosphere; after the reaction is completed, the organic solvent is spun dry, and column chromatography is performed to separate a dialdehyde precursor compound (e);

[0018] (3) the dialdehyde precursor compound (e) prepared in step (2) and an indenone compound (f) are dissolved in an organic solvent at a molar ratio of 1:2-4, acetic anhydride and boron trifluoride ether are added, and the mixture is reacted for 30-600 minutes; after the reaction is completed, the organic solvent is spun dry, and column chromatography is performed to separate a dimer-type acceptor material (g).

[0019] Optionally, the organic solvent is chloroform, toluene, chlorobenzene or tetrahydrofuran; the catalyst is Pd(PPh3)4, Pd(PPh3)2Cl2 or Pd2(dba)3; and the ligand is P(o-tol)3 or P(t-Bu)3.

[0020] The application provides application of a dimer-type acceptor material based on an electron-withdrawing bridging unit in preparation of a photoelectric functional device.

[0021] Optionally, the photoelectric functional device is an organic solar cell, and the dimer-type acceptor material is used as an active layer acceptor material to prepare a photoactive layer of the organic solar cell by mixing with a donor material.

[0022] Optionally, the photoactive layer has a thickness of 80-120 nm.

[0023] Compared with the prior art, the application has the following beneficial effects: the dimer acceptor material constructed in the application selects a planar rigid unit with electron-withdrawing capacity as a bridging unit and selects a benzotriazole unit with electron-withdrawing capacity as a central core, so that the LUMO energy level of the material is raised, the glass transition temperature is increased, the absorption spectrum is effectively widened, the device voltage loss is reduced, and the non-covalent bond existing in the molecule can enhance the intermolecular force while keeping the molecular planarity.

[0024] The material has a high glass transition temperature and a low diffusion coefficient (which can be converted from the glass transition temperature), and the use of the material in a photoelectric functional device can improve the stability of the device, for example, the use of the material in preparation of an active layer of a solar cell can obtain high open-circuit voltage and high-stability OSCs. Due to the introduction of the planar rigid unit, the protected molecules have a greatly improved glass transition temperature (not less than 190 DEG C) and a reduced molecular diffusion kinetic process, and the use of the material as an active layer acceptor material of an organic solar cell can form a stable active layer morphology, and finally realize effective improvement of the stability of the device, which has very important significance for realizing commercial application of the organic solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic diagram of a layer structure of an organic solar cell device according to an embodiment of the application.

[0026] Figure 2 is a chemical structural formula of a donor material PM6 in an active layer of an organic solar cell device according to an embodiment of the application.

[0027] Figure 3 is a chemical structural formula of an electron transport layer material PDINN in an organic solar cell device according to an embodiment of the application.

[0028] Figure 4 is a chemical structural formula of a hole transport layer material 2PACz in an organic solar cell device according to an embodiment of the application.

[0029] Figure 5is a chemical reaction line chart in preparation of the dimer type acceptor material in an embodiment of the present application;

[0030] Figure 6 is a structural general formula of the dimer type acceptor material based on the electron-withdrawing bridging unit in an embodiment of the present application. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0032] The present application provides a kind of dimer acceptor material based on electron-withdrawing bridging unit, which is combined by one bridging unit and two small molecule acceptors, and its structural general formula is shown as (I):

[0033]

[0034] In (I), Ar is a rigid electron-withdrawing unit with π conjugated structure; R1, R2 and R3 are linear or branched alkyl with 8-25 carbon atoms; X and Y are the same or different hydrogen atom, F, Cl or Br; Z is hydrogen atom, F, Cl or Br.

[0035] Further, the Ar structural formula is one of (II):

[0036]

[0037] Wherein R is H atom or linear or branched alkyl with 8-25 carbon atoms.

[0038] The preparation method of the dimer acceptor material based on electron-withdrawing bridging unit provided by the present application is prepared by three reactions with dialdehyde substituted compound (a), Br substituted indenone compound (b), bistrimethyltin substituted Ar compound (d) and indenone compound (f) as reactants. The organic solvent used in the reaction process can be chloroform, toluene, chlorobenzene or tetrahydrofuran.

[0039] Reference Figure 5 As shown, comprising the following steps:

[0040] (1) The dialdehyde substituted compound (a) and the Br substituted indenone compound (b) are dissolved in an organic solvent at a molar ratio of 1:0.8-1.2, and acetic anhydride and boron trifluoride ether are added and reacted for 30-90 minutes. After the reaction is completed, the organic solvent is spun dry, and column chromatography is used to separate the single-side precursor compound (c).

[0041] (2) The single-side precursor compound (c) prepared in step (1) and the bistrimethyltin substituted Ar compound (d) are dissolved in an organic solvent at a molar ratio of 2-2.5:1, and a catalyst, a ligand, and cuprous iodide are added, and reacted at 100-150°C for 12-36 hours under an inert gas atmosphere. After the reaction is completed, the organic solvent is spun dry, and column chromatography is used to separate the dialdehyde precursor compound (e). The catalyst can be Pd(PPh3)4, Pd2(dba)3, or Pd(PPh3)2Cl2. The ligand can be P(o-tol)3 or P(t-Bu)3.

[0042] (3) The dialdehyde precursor compound (e) prepared in step (2) and the indenone compound (f) are dissolved in an organic solvent at a molar ratio of 1:2-4, and acetic anhydride and boron trifluoride ether are added and reacted for 30-600 minutes. After the reaction is completed, the organic solvent is spun dry, and column chromatography is used to separate the dimer-type acceptor material (g).

[0043] The application also provides a use of the dimer-type acceptor material based on the electron-withdrawing bridging unit in the preparation of a photoelectric functional device. For example, in an organic solar cell device. Figure 1 The structure of an organic solar cell device in an embodiment of the application is schematically shown. As shown in Figure 1 , the layer structure of the organic solar cell device includes a substrate layer 1, a hole transport layer 2, an active layer 3, an electron transport layer 4, and an electrode 5. The substrate layer 1 can be an ITO substrate. The hole transport layer 2 can be PEDOT:PSS, 2PACz (structural formula as Figure 4 ), or ZnO, and has a thickness of 20-40 nm. The active layer 3 can be a blended thin film of a donor material PM6 (structural formula as Figure 2 ) and any dimer-type acceptor material in the application, and has a thickness of 80-120 nm. The electron transport layer 4 can be MoO3 or PDINN (structural formula as Figure 3 ), and has a thickness of 5-10 nm. The electrode 5 can be an Al or Ag electrode, and has a thickness of 80-100 nm. By using the dimer-type acceptor material in the application to prepare the active layer in an organic solar cell, an OSC with high open voltage and high stability can be obtained.

[0044] The technical solutions of the present application are described more clearly and in detail below in combination with specific examples. In the following examples, the reactants are reacted according to the corresponding molar mass, and the mass of the reactants is calculated according to the molar mass.

[0045] Example 1: Synthesis of dimer-type acceptor material Dimer-1

[0046]

[0047] First step, in a reaction bottle, add dialdehyde end group precursor SMA1 (500 mg, 0.34 mmol), 5-bromo cyanoinde ketone (92 mg, 0.34 mmol) and 50 mL of tetrahydrofuran, under argon protection, drop 0.5 mL of acetic anhydride and 0.6 mL of boron trifluoride ether at room temperature, react for 30 min. After the reaction is completed, spin dry the solvent, and the crude product is settled in methanol. The obtained solid is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain 350 mg of single side precursor compound, with a yield of 60%.

[0048] Second step, in a two-necked bottle, add single side precursor compound (200 mg, 0.11 mmol), bridging unit B1 (40 mg, 0.05 mmol), Pd(PPh3)4 (13 mg, 0.01 mmol), and 40 mL of toluene, reflux under argon protection for 24 h. After the reaction is completed, extract the reaction solution with dichloromethane, dry with anhydrous sodium sulfate, spin dry the solvent to obtain the crude product. The obtained crude product is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1) to obtain 132 mg of dialdehyde end group precursor compound of dimer-type acceptor material, with a yield of 67%.

[0049] Third step, in a reaction bottle, add dialdehyde end group precursor compound of dimer-type acceptor material (120 mg, 0.03 mmol), difluorobiscyanoinde ketone (21 mg, 0.09 mmol) and 20 mL of toluene, under argon protection, drop 0.3 mL of acetic anhydride and 0.4 mL of boron trifluoride ether at room temperature, react for 70 min. After the reaction is completed, spin dry the solvent, and the crude product is settled in methanol. The obtained solid is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1) to obtain 123 mg of dimer-type acceptor material Dimer-1, with a yield of 92%.

[0050] Example 2: Synthesis of dimer-type acceptor material Dimer-2

[0051]

[0052] First step, in a reaction flask, add dialdehyde end group precursor SMA2 (400 mg, 0.27 mmol), 5-bromo cyanoinindanone (74 mg, 0.27 mmol) and 50 mL of toluene, under argon protection, drop 0.4 mL of acetic anhydride and 0.4 mL of boron trifluoride etherate at room temperature, react for 35 min. After the reaction is completed, spin dry the solvent, and the crude product is settled in methanol, and the obtained solid is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 5: 1) to obtain 261 mg of single precursor compound, with a yield of 55%.

[0053] Second step, in a two-necked flask, add single precursor compound (200 mg, 0.11 mmol), bridging unit B2 (30 mg, 0.05 mmol), Pd(PPh3)4(16 mg, 0.01 mmol), and 45 mL of toluene, under argon protection, reflux for 36 h. After the reaction is completed, extract the reaction solution with dichloromethane, dry with anhydrous sodium sulfate, spin dry the solvent to obtain the crude product. After the obtained crude product is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3: 1), 123 mg of dimer-type acceptor material dialdehyde end group precursor compound is obtained, with a yield of 67%.

[0054] Third step, in a reaction flask, add dimer-type acceptor material dialdehyde end group precursor compound (100 mg, 0.03 mmol), dichlorodicyanoinindanone (16 mg, 0.06 mmol) and 15 mL of toluene, under argon protection, drop 0.2 mL of acetic anhydride and 0.3 mL of boron trifluoride etherate at room temperature, react for 80 min. After the reaction is completed, spin dry the solvent, and the crude product is settled in methanol, and the obtained solid is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3: 1) to obtain dimer-type acceptor material Dimer-2 (98 mg, yield 86%).

[0055] Example 3: Synthesis of dimer-type acceptor material Dimer-3

[0056]

[0057] First step, in a reaction flask, add dialdehyde end group precursor SMA2 (400 mg, 0.27 mmol), 5-bromo cyanoinindanone (74 mg, 0.27 mmol) and 50 mL of toluene, under argon protection, drop 0.4 mL of acetic anhydride and 0.4 mL of boron trifluoride etherate at room temperature, react for 35 min. After the reaction is completed, spin dry the solvent, and the crude product is settled in methanol, and the obtained solid is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 5: 1) to obtain 261 mg of single precursor compound, with a yield of 55%.

[0058] Second step, add monomeric precursor compound (192 mg, 0.12 mmol), bridging unit B3 (34 mg, 0.05 mmol), Pd(PPh3)2Cl2(7 mg, 0.01 mmol) and 40 mL of toluene into two flasks, reflux the reaction under argon protection for 24 h. After the reaction is completed, extract the reaction solution with dichloromethane, dry with anhydrous sodium sulfate, and spin dry the solvent to obtain the crude product. After column chromatography separation and purification (eluent: petroleum ether:dichloromethane = 3:1) of the obtained crude product, 137 mg of dimeric acceptor material dialdehyde end group precursor compound is obtained with a yield of 80%.

[0059] Third step, add dimeric acceptor material dialdehyde end group precursor compound (130 mg, 0.04 mmol), dicyanoindanone (20 mg, 0.10 mmol) and 20 mL of toluene into a reaction flask, and drop 0.3 mL of acetic anhydride and 0.3 mL of boron trifluoride ether under argon protection at room temperature, and react for 65 min. After the reaction is completed, spin dry the solvent, and the crude product is settled in methanol. After column chromatography separation and purification (eluent: petroleum ether:dichloromethane = 3:1) of the obtained solid, dimeric acceptor material Dimer-3 (132 mg, yield 92%) is obtained.

[0060] Example 4: Synthesis of dimeric acceptor material Dimer-4

[0061]

[0062] First step, add dialdehyde end group precursor SMA1 (500 mg, 0.31 mol), 5-bromo dicyanoindanone (88 mg, 0.32 mol) and 50 mL of chloroform into a reaction flask, and drop 0.3 mL of acetic anhydride and 0.3 mL of boron trifluoride ether under argon protection at room temperature, and react for 30 min. After the reaction is completed, spin dry the solvent, and the crude product is settled in methanol. After column chromatography separation and purification (eluent: petroleum ether:dichloromethane = 4:1) of the obtained solid, 360 mg of monomeric precursor compound is obtained with a yield of 62%.

[0063] Second step, add monomeric precursor compound (182 mg, 0.10 mmol), bridging unit B4 (40 mg, 0.04 mmol), Pd2(dba)3(9 mg, 0.01 mmol), P(t-Bu)3(6 mg, 0.03 mmol) and 42 mL of toluene into two flasks, reflux the reaction under argon protection for 30 h. After the reaction is completed, extract the reaction solution with dichloromethane, dry with anhydrous sodium sulfate, and spin dry the solvent to obtain the crude product. After column chromatography separation and purification (eluent: petroleum ether:dichloromethane = 4:1) of the obtained crude product, 121 mg of dimeric acceptor material dialdehyde end group precursor compound is obtained with a yield of 68%.

[0064] Third step, in a reaction flask, add dimer type acceptor material dialdehyde end group precursor compound (110 mg, 0.03 mmol), difluorobiscyanoinde (18 mg, 0.08 mmol) and 14 mL of toluene, under argon protection, drop 0.2 mL of acetic anhydride and 0.4 mL of boron trifluoride ether, react for 180 min at room temperature. After the reaction is completed, spin dry the solvent, and the crude product is settled in methanol, and the obtained solid is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1) to obtain dimer type acceptor material Dimer-4 (110 mg, yield 91%).

[0065] Example 5: Synthesis of dimer type acceptor material Dimer-5

[0066]

[0067] First step, in a reaction flask, add dialdehyde end group precursor SMA2 (500 mg, 0.34 mmol), 1,2-(5-bromo-6-fluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene) propanedinitrile (99 mg, 0.34 mmol) and 48 mL of chlorobenzene, under argon protection, drop 0.3 mL of acetic anhydride and 0.4 mL of boron trifluoride ether, react for 30 min at room temperature. After the reaction is completed, spin dry the solvent, and the crude product is settled in methanol, and the obtained solid is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain single side precursor compound 343 mg, yield 58%.

[0068] Second step, in a two-neck flask, add single side precursor compound (210 mg, 0.12 mmol), bridging unit B5 (40 mg, 0.05 mmol), Pd2(dba)3 (9 mg, 0.01 mmol), P(o-tol)3 (20 mg, 0.05 mmol) and 45 mL of toluene, react under argon protection for 19 h at reflux. After the reaction is completed, extract the reaction solution with dichloromethane, dry with anhydrous sodium sulfate, spin dry the solvent to obtain the crude product. The obtained crude product is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1) to obtain dimer type acceptor material dialdehyde end group precursor compound 142 mg, yield 71%.

[0069] Third step, add dimeric acceptor material dialdehyde end group precursor compound (140 mg, 0.04 mmol), difluorodicyanoinindanone (26 mg, 0.11 mmol) and 16 mL of toluene in a reaction bottle, under argon protection, drop 0.3 mL of acetic anhydride and 0.5 mL of boron trifluoride ether at room temperature, react for 150 min. After the reaction is completed, spin dry the solvent, and the crude product is settled in methanol. The obtained solid is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain dimeric acceptor material Dimer-6 (139 mg, yield 90%).

[0070] Example 6: Synthesis of dimeric acceptor material Dimer-6

[0071]

[0072] First step, add dialdehyde end group precursor SMA2 (500 mg, 0.34 mmol), 5- bromocyanoinindanone (92 mg, 0.34 mmol) and 48 mL of chlorobenzene in a reaction bottle, under argon protection, drop 0.3 mL of acetic anhydride and 0.5 mL of boron trifluoride ether at room temperature, react for 30 min. After the reaction is completed, spin dry the solvent, and the crude product is settled in methanol. The obtained solid is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain single side precursor compound 360 mg, yield 61%.

[0073] Second step, add single side precursor compound (210 mg, 0.12 mmol), bridging unit B6 (45 mg, 0.05 mmol), Pd2(dba)3(9 mg, 0.01 mmol), P(o-tol)3(20 mg, 0.05 mmol) and 45 mL of toluene in a two-necked bottle, under argon protection, reflux for 18 h. After the reaction is completed, extract the reaction solution with dichloromethane, dry with anhydrous sodium sulfate, spin dry the solvent to obtain the crude product. The obtained crude product is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1) to obtain dimeric acceptor material dialdehyde end group precursor compound 137 mg, yield 67%.

[0074] Third step, add dimeric acceptor material dialdehyde end group precursor compound (140 mg, 0.04 mmol), difluorodicyanoinindanone (26 mg, 0.11 mmol) and 16 mL of toluene in a reaction bottle, under argon protection, drop 0.3 mL of acetic anhydride and 0.5 mL of boron trifluoride ether at room temperature, react for 150 min. After the reaction is completed, spin dry the solvent, and the crude product is settled in methanol. The obtained solid is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain dimeric acceptor material Dimer-6 (139 mg, yield 90%).

[0075] Example 7: Synthesis of dimer-type acceptor material Dimer-7

[0076]

[0077] First step, in a reaction flask, add dialdehyde end group precursor SMA2 (500 mg, 0.34 mmol), 5-bromo cyanoinde ketone (92 mg, 0.34 mmol) and 48 mL chlorobenzene, under argon protection, drop 0.3 mL acetic anhydride and 0.5 mL boron trifluoride etherate at room temperature, react for 30 min. After the reaction is completed, spin dry the solvent, and the crude product is settled in methanol, and the obtained solid is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain 360 mg of single side precursor compound, with a yield of 61%.

[0078] Second step, in a two-neck flask, add single side precursor compound (150 mg, 0.12 mmol), bridging unit B6 (42 mg, 0.04 mmol), Pd2(dba)3(10 mg, 0.01 mmol), P(o-tol)3(20 mg, 0.05 mmol) and 35 mL toluene, reflux under argon protection for 24 h. After the reaction is completed, extract the reaction solution with dichloromethane, dry with anhydrous sodium sulfate, spin dry the solvent to obtain the crude product. The obtained crude product is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain 101 mg of dialdehyde end group precursor compound of dimer-type acceptor material, with a yield of 64%.

[0079] Third step, in a reaction flask, add dialdehyde end group precursor compound of dimer-type acceptor material (100 mg, 0.03 mmol), difluorobiscyanoinde ketone (18 mg, 0.08 mmol) and 15 mL toluene, under argon protection, drop 0.4 mL acetic anhydride and 0.4 mL boron trifluoride etherate at room temperature, react for 200 min. After the reaction is completed, spin dry the solvent, and the crude product is settled in methanol, and the obtained solid is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain 98 mg of dimer-type acceptor material Dimer-6, with a yield of 89%.

[0080] Example 8: Test of glass transition temperature of dimer-type acceptor material

[0081] The dimer-type acceptor materials obtained in Examples 1-7 are tested for glass transition temperature, and the specific process is as follows:

[0082] The solution (chloroform solution of Dimer-1 to Dimer-7, solution concentration = 10 mg / mL) was prepared into a thin film on a quartz glass substrate by spin coating, and the glass transition temperature of Dimer-1 to Dimer-7 was obtained by measuring the red shift deviation degree of the temperature change of the ultraviolet-visible absorption spectrum, as shown in Table 1 below.

[0083] Table 1 Glass transition temperature of Dimer-1 to Dimer-7

[0084]

[0085]

[0086] As can be seen from Table 1, the glass transition temperature of the dimer-type acceptor materials Dimer-1 to Dimer-7 prepared in the above examples is increased, and is not less than 190°C.

[0087] Example 9: Device preparation of organic solar cell based on dimer-type acceptor material

[0088] The dimer-type acceptor materials obtained in Examples 1 to 7 were used as active layer acceptor materials to prepare organic solar cell devices, and the specific preparation process was as follows:

[0089] The active layer solution (donor material and acceptor material in the same proportion, such as PM6:Dimer-1 = 1:1, solution concentration = 14 mg / mL) was prepared into a photoactive layer on a 2PACz modified ITO glass substrate by spin coating, and the active layer was subjected to heat annealing treatment (100°C / 10min), then a layer of PDINN (concentration: 1.0 mg mL -1 of methanol solution) was spin coated, and finally Ag was evaporated to prepare a cathode.

[0090] Photovoltaic device performance: under AM 1.5G (100 mW cm -2 ) irradiation, the device performance and T 90 (holding 90% of the initial efficiency for a period of time) lifetime of the device were as shown in Table 2 below, wherein V oc represents open circuit voltage, J sc represents short circuit current, FF represents fill factor, and PCE represents photoelectric conversion efficiency.

[0091] Table 2 Photovoltaic device performance

[0092] Active layer V oc (V) J sc (V)]]> FF (%) PCE (%) T 90 (h)]]> PM6:Dimer-1 1.03 22.23 75 17.17 1487 PM6:Dimer-2 1.00 23.27 76 17.69 1858 PM6:Dimer-3 1.08 22.15 74 17.70 2126 PM6:Dimer-4 1.01 22.52 75 17.06 1688 PM6:Dimer-5 0.99 24.15 76 18.17 1425 PM6:Dimer-6 0.99 23.38 74 17.13 1476 PM6:Dimer-7 0.99 23.86 76 17.95 1852

[0093] As can be seen from the above table, the organic solar cell device prepared by using the dimer type acceptor material prepared in the above examples as the active layer acceptor material has an open circuit voltage ≥ 0.99V, a T 90 The photoelectric conversion efficiency is all > 17% over 1400h, especially over 2000h.

[0094] The description of the application is given for the purpose of exemplification and description and is not intended to be exhaustive or to limit the application to the precise form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. Embodiments are chosen and described in order to best explain the principles of the application and its practical application to thereby enable others skilled in the art to best utilize the application with various modifications as are suited to the particular use contemplated.

Claims

1. A class of dimeric acceptor materials based on electron-withdrawing bridging units characterized in that, The structural general formula of the acceptor material is (I): In (I), R1, R2 and R3 are linear or branched alkyl groups with 8-25 carbon atoms; X and Y are the same or different hydrogen atoms, F, Cl or Br; and Z is a hydrogen atom, F, Cl or Br. The Ar structural formula is one of (II): In which R is a hydrogen atom or a linear or branched alkyl group with 8-25 carbon atoms.

2. The dimer-type acceptor material based on an electron-withdrawing bridging unit according to claim 1, characterized in that The glass transition temperature of the acceptor material is ≥ 190°C.

3. A method of producing a dimeric acceptor material based on an electron- withdrawing bridging unit according to claim 1, characterized by, The synthesis reaction equation of the acceptor material is (III): In which (g) is the reagent of the structural general formula (I) in claim 1.

4. The production method according to claim 3, characterized by, The preparation method comprises the following steps: (1) Dissolve the dialdehyde-substituted compound (a) and the Br-substituted indenone compound (b) in an organic solvent at a molar ratio of 1:0.8-1.2, add acetic anhydride and boron trifluoride ether, and react for 30-90 minutes. After the reaction is completed, spin dry the organic solvent, and separate the single-side precursor compound (c) by column chromatography; (2) Dissolve the single-side precursor compound (c) prepared in step (1) and the bistrimethyltin-substituted Ar compound (d) in an organic solvent at a molar ratio of 2-2.5:1, add a catalyst, a ligand and cuprous iodide, and react at 100-150°C for 12-36 hours under an inert gas atmosphere. After the reaction is completed, spin dry the organic solvent, and separate the dialdehyde precursor compound (e) by column chromatography; (3) Dissolve the dialdehyde precursor compound (e) prepared in step (2) and the indenone compound (f) in an organic solvent at a molar ratio of 1:2-4, add acetic anhydride and boron trifluoride ether, and react for 30-600 minutes. After the reaction is completed, spin dry the organic solvent, and separate the dimer-type acceptor material (g) by column chromatography.

5. The production method according to claim 4, characterized by, The organic solvent is chloroform, toluene, chlorobenzene or tetrahydrofuran; the catalyst is Pd(PPh3)4, Pd(PPh3)2Cl2 or Pd2(dba)3; and the ligand is P(o-tol)3 or P(t-Bu)3.

6. Use of the dimer-type acceptor material based on an electron-withdrawing bridging unit according to any one of claims 1-2 in the preparation of a photoelectric functional device.

7. Use according to claim 6, characterized in that, The photoelectric functional device is an organic solar cell, wherein the dimer-type acceptor material is used as an active layer acceptor material to prepare a photoactive layer of an organic solar cell by mixing with a donor material.

8. Use according to claim 7, characterized in that, The thickness of the photoactive layer is 80-120 nm.

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