Dimer acceptor material based on electron-withdrawing bridging unit as well as preparation method and application of dimer acceptor material

Abstract

The invention provides a dimer acceptor material based on an electron-withdrawing bridging unit as well as a preparation method and application of the dimer acceptor material. The structural general formula of the dimer type acceptor material is (I), and the dimer type acceptor material is constructed by taking a benzotriazole unit with electron-withdrawing capability as a central core and taking a planar rigid unit with electron-withdrawing capability as a bridging unit. The acceptor material has a relatively high glass transition temperature and a relatively low diffusion coefficient. The material is used in a photoelectric functional device, can stabilize the film morphology of an active layer, and finally can effectively improve the stability of the device, for example, as an active layer acceptor material of an organic solar cell, can promote commercial application of the organic solar cell.

Description

Technical Field

[0001] The present invention belongs to the field of organic photovoltaic technology, and specifically relates to a type of dimer-type receptor material based on electron-withdrawing bridging units, a preparation method thereof, and an application thereof in the preparation of optoelectronic functional devices such as organic solar cells. Background Art

[0002] As environmental pollution and energy crisis become increasingly serious, the search and development of renewable energy has become an important issue in the development of human society. Among many renewable energy sources (such as solar energy, wind energy, tidal energy, geothermal energy, etc.), solar energy has attracted extensive attention from industry and academia due to its advantages of being pollution-free, widely available, and inexhaustible, and has made great progress.

[0003] Organic solar cells (OSCs) are currently the hot third-generation photovoltaic technology. They have attracted widespread attention due to their advantages such as wide source of active layers, light weight, flexible preparation, strong processability and simple manufacturing process (roll-to-roll, printing, spin coating, spray coating, etc.). Currently, organic solar cells have entered a rapid development stage, and their power conversion efficiency (PCE) has exceeded 20%, with broad application prospects. However, their stability issues have become a bottleneck for commercial applications.

[0004] Dimer receptor materials have become strong competitors for small molecule receptors and polymer receptors due to their advantages such as clear structure, good batch reproducibility, good film-forming property, low diffusion coefficient and good stability. However, most of the current dimer materials use electron-donating units such as thiophene, ethylene, acetylene, thiophene-ethylene-thiophene, thiophene-alkyl chain-thiophene as bridging units, and their glass transition temperatures are all lower than 150°C. The low glass transition temperature and high diffusion coefficient make the molecules more prone to excessive aggregation under thermal stress, which is not conducive to the morphological stability of the active layer and the long service life of the device. Summary of the invention

[0005] The purpose of the present invention is to provide a type of dimer receptor material based on electron-withdrawing bridging units and its preparation method and application, the material has a high glass transition temperature, and can be used in optoelectronic functional devices to improve the stability of the device. The above purpose can be achieved by the implementation of the following technical solutions:

[0006] The present invention provides a type of dimer-type receptor material based on electron-withdrawing bridging units, and the general structural formula of the receptor material is (I):

[0007]

[0008] Wherein, in (I), Ar is a rigid electron-withdrawing unit with a π-conjugated structure; R1, R2 and R3 are straight-chain 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 (II):

[0010]

[0011] Wherein R is a H atom or a straight or branched alkyl group having 8 to 25 carbon atoms.

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

[0013] Optionally, the synthetic reaction equation of the receptor material is (III):

[0014]

[0015] The present invention provides a method for preparing a type of dimer-type receptor material based on an electron-withdrawing bridging unit, the preparation method comprising the following steps:

[0016] (1) dissolving a dialdehyde substituted compound (a) and a Br-substituted indone compound (b) in an organic solvent at a molar ratio of 1:0.8-1.2, and adding acetic anhydride and boron trifluoride etherate to react for 30-90 minutes. After the reaction is completed, the organic solvent is dried and separated by column chromatography to obtain a unilateral precursor compound (c);

[0017] (2) dissolving the unilateral 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, adding a catalyst, a ligand and cuprous iodide, reacting at 100-150° C. for 12-36 hours under an inert gas atmosphere, and after the reaction is completed, drying the organic solvent, and separating by column chromatography to obtain a dialdehyde precursor compound (e);

[0018] (3) The dialdehyde precursor compound (e) prepared in step (2) and the indone compound (f) are dissolved in an organic solvent at a molar ratio of 1:2-4, acetic anhydride and boron trifluoride etherate are added to react for 30-600 minutes. After the reaction is completed, the organic solvent is dried and separated by column chromatography to obtain a dimer receptor 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 present invention provides a type of dimer receptor material based on electron-withdrawing bridging units and its application in the preparation of optoelectronic functional devices.

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

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

[0023] Compared with the prior art, the present invention has the following beneficial effects: the dimer receptor material constructed by the present invention selects a planar rigid unit with electron-withdrawing ability as a bridging unit, and selects a benzotriazole unit with electron-withdrawing ability as a central core, so that the LUMO energy level of the material itself is increased, the glass transition temperature is increased, the absorption spectrum is effectively broadened, and the voltage loss of the device is reduced. In addition, the non-covalent bonds in the molecules can enhance the intermolecular forces while maintaining the planarity of the molecules.

[0024] The material has a high glass transition temperature and a low diffusion coefficient (which can be converted from the glass transition temperature). The use of this material in optoelectronic functional devices can improve the stability of the device. For example, when used to prepare the active layer of solar cells, OSCs with high opening voltage and high stability can be obtained. Due to the introduction of planar rigid units, the protected molecules have a greatly improved glass transition temperature (not less than 190°C) and the kinetic process of molecular diffusion is reduced. The material is used as an active layer receptor material for organic solar cells, thereby forming a stable active layer morphology, and ultimately achieving an effective improvement in device stability, which is of great significance for the commercial application of organic solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the layer structure of an organic solar cell device according to an embodiment of the present invention.

[0026] Figure 2 It is the chemical structural formula of the donor material PM6 in the active layer of the organic solar cell device according to one embodiment of the present invention.

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

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

[0029] Figure 5It is a chemical reaction circuit diagram for preparing a dimer type receptor material in one embodiment of the present invention;

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

[0031] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The present invention provides a type of dimer receptor material based on an electron-withdrawing bridging unit, which is composed of a bridging unit and two small molecule receptors, and its general structural formula is shown in (I):

[0033]

[0034] Wherein, in (I), Ar is a rigid electron-withdrawing unit with a π-conjugated structure; R1, R2 and R3 are straight-chain 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.

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

[0036]

[0037] Wherein R is a H atom or a straight or branched alkyl group having 8 to 25 carbon atoms.

[0038] The present invention provides a method for preparing a class of dimer receptor materials based on electron-withdrawing bridging units, which is prepared by performing three reactions using a dialdehyde substituted compound (a), a Br-substituted indanone compound (b), a bistrimethyltin substituted Ar compound (d), and an indanone compound (f) as reactants. The organic solvent used in the reaction process can be chloroform, toluene, chlorobenzene or tetrahydrofuran.

[0039] refer to Figure 5 As shown, the following steps are included:

[0040] (1) A dialdehyde substituted compound (a) and a Br-substituted indone compound (b) are dissolved in an organic solvent at a molar ratio of 1:0.8-1.2, and acetic anhydride and boron trifluoride etherate are added to react for 30-90 minutes. After the reaction is completed, the organic solvent is dried and separated by column chromatography to obtain a unilateral precursor compound (c).

[0041] (2) The unilateral precursor compound (c) prepared in step (1) and the Ar compound (d) substituted with trimethyltin 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 the reaction is carried out at 100-150° C. for 12-36 hours under an inert gas atmosphere. After the reaction is completed, the organic solvent is dried and separated by column chromatography to obtain a dialdehyde precursor compound (e). The catalyst may be Pd(PPh3)4, Pd2(dba)3 or Pd(PPh3)2Cl2. The ligand may be P(o-tol)3 or P(t-Bu)3.

[0042] (3) The dialdehyde precursor compound (e) prepared in step (2) and the indone compound (f) are dissolved in an organic solvent at a molar ratio of 1:2-4, acetic anhydride and boron trifluoride etherate are added to react for 30-600 minutes. After the reaction is completed, the organic solvent is dried and separated by column chromatography to obtain a dimer receptor material (g).

[0043] The present invention also provides an application of the aforementioned type of dimer-type acceptor material based on electron-withdrawing bridging units in the preparation of optoelectronic functional devices, for example, in organic solar cell devices. Figure 1 The structure of an organic solar cell device in one embodiment of the present invention is schematically shown. Figure 1 As shown, 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 (structure formula as shown in FIG. Figure 4 ) or ZnO, and its thickness is 20-40nm. The active layer 3 can be a donor material PM6 (structural formula as Figure 2 ) and any dimer type receptor material of the present invention, the thickness of which is 80-120 nm. The electron transport layer 4 can be MoO3 or PDINN (structural formula: Figure 3 ), with a thickness of 5-10 nm. The electrode 5 may be an Al or Ag electrode, with a thickness of 80-100 nm. By using the dimer type acceptor material of the present invention to prepare the active layer in the organic solar cell, OSCs with high opening voltage and high stability can be obtained.

[0044] The technical solution of the present invention is described in more detail below in conjunction with specific embodiments. In the following embodiments, the reactants are reacted according to the corresponding molar masses, and the masses of the reactants are calculated based on the molar masses.

[0045] Example 1: Synthesis of Dimer-1

[0046]

[0047] In the first step, the dialdehyde terminal precursor SMA1 (500 mg, 0.34 mmol), 5-bromocyanoindanone (92 mg, 0.34 mmol) and 50 mL tetrahydrofuran were added to the reaction bottle, and 0.5 mL acetic anhydride and 0.6 mL boron trifluoride ether were added dropwise at room temperature under argon protection, and the reaction was carried out for 30 minutes. After the reaction was completed, the solvent was dried, and the crude product was precipitated in methanol. The obtained solid was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain 350 mg of the unilateral precursor compound with a yield of 60%.

[0048] In the second step, a unilateral precursor compound (200 mg, 0.11 mmol), a bridging unit B1 (40 mg, 0.05 mmol), Pd(PPh3)4 (13 mg, 0.01 mmol), and 40 mL of toluene were added to a two-necked bottle and refluxed for 24 h under argon protection. After the reaction was completed, the reaction solution was extracted with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was spin-dried to obtain a crude product. The obtained crude product was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1) to obtain 132 mg of a dimeric receptor material dialdehyde terminal precursor compound with a yield of 67%.

[0049] In the third step, the dimeric receptor material dialdehyde terminal precursor compound (120 mg, 0.03 mmol), difluorobiscyanoindanone (21 mg, 0.09 mmol) and 20 mL toluene were added to the reaction bottle, and 0.3 mL acetic anhydride and 0.4 mL boron trifluoride ether were added dropwise at room temperature under argon protection, and the reaction was carried out for 70 minutes. After the reaction was completed, the solvent was dried, and the crude product was precipitated in methanol. The obtained solid was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1) to obtain the dimeric receptor material Dimer-1 (123 mg, yield 92%).

[0050] Example 2: Synthesis of Dimer-2

[0051]

[0052] In the first step, the dialdehyde terminal precursor SMA2 (400 mg, 0.27 mmol), 5-bromocyanoindanone (74 mg, 0.27 mmol) and 50 mL toluene were added to the reaction bottle, and 0.4 mL acetic anhydride and 0.4 mL boron trifluoride ether were added dropwise at room temperature under argon protection, and the reaction was carried out for 35 minutes. After the reaction was completed, the solvent was dried, and the crude product was precipitated in methanol. The obtained solid was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 5:1) to obtain 261 mg of the unilateral precursor compound with a yield of 55%.

[0053] In the second step, a unilateral precursor compound (200 mg, 0.11 mmol), a bridging unit B2 (30 mg, 0.05 mmol), Pd(PPh3)4 (16 mg, 0.01 mmol), and 45 mL of toluene were added to a two-necked bottle, and the mixture was refluxed for 36 h under argon protection. After the reaction, the reaction solution was extracted with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was dried to obtain a crude product. The crude product was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1), and 123 mg of a dimeric receptor material dialdehyde terminal precursor compound was obtained with a yield of 67%.

[0054] In the third step, the dimeric receptor material dialdehyde terminal precursor compound (100 mg, 0.03 mmol), dichlorobiscyanoindanone (16 mg, 0.06 mmol) and 15 mL toluene were added to the reaction bottle, and 0.2 mL acetic anhydride and 0.3 mL boron trifluoride ether were added dropwise at room temperature under argon protection, and the reaction was carried out for 80 minutes. After the reaction was completed, the solvent was dried by spin drying, and the crude product was precipitated in methanol. The obtained solid was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1) to obtain the dimeric receptor material Dimer-2 (98 mg, yield 86%).

[0055] Example 3: Synthesis of Dimer-3

[0056]

[0057] In the first step, the dialdehyde terminal precursor SMA3 (500 mg, 0.37 mmol), 5-bromocyanoindanone (102 mg, 0.37 mmol) and 48 mL of chloroform were added to the reaction bottle, and 0.5 mL of acetic anhydride and 0.7 mL of boron trifluoride ether were added dropwise at room temperature under argon protection, and the reaction was carried out for 60 minutes. After the reaction was completed, the solvent was dried by spin drying, and the crude product was precipitated in methanol. The obtained solid was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain 320 mg of the unilateral precursor compound with a yield of 54%.

[0058] In the second step, a unilateral precursor compound (192 mg, 0.12 mmol), a bridging unit B3 (34 mg, 0.05 mmol), Pd(PPh3)2Cl2 (7 mg, 0.01 mmol), and 40 mL of toluene were added to a two-necked bottle, and the mixture was refluxed for 24 h under argon protection. After the reaction, the reaction solution was extracted with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was dried to obtain a crude product. The crude product was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1), and 137 mg of a dimeric receptor material dialdehyde terminal precursor compound was obtained with a yield of 80%.

[0059] In the third step, a dialdehyde terminal precursor compound (130 mg, 0.04 mmol), dicyanoindanone (20 mg, 0.10 mmol) and 20 mL toluene were added to the reaction bottle, and 0.3 mL acetic anhydride and 0.3 mL boron trifluoride ether were added dropwise under argon protection at room temperature for 65 min. After the reaction, the solvent was dried, the crude product was precipitated in methanol, and the obtained solid was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1) to obtain the dimeric receptor material Dimer-3 (132 mg, yield 92%).

[0060] Example 4: Synthesis of Dimer-4

[0061]

[0062] In the first step, the dialdehyde terminal precursor SMA1 (500 mg, 0.31 mol), 5-bromocyanoindanone (88 mg, 0.32 mol) and 50 mL of chloroform were added to the reaction bottle, and 0.3 mL of acetic anhydride and 0.3 mL of boron trifluoride ether were added dropwise at room temperature under argon protection, and the reaction was carried out for 30 minutes. After the reaction was completed, the solvent was dried by spin drying, and the crude product was precipitated in methanol. The obtained solid was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1), and 360 mg of the unilateral precursor compound was obtained with a yield of 62%.

[0063] In the second step, a unilateral precursor compound (182 mg, 0.10 mmol), a 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 were added to a two-necked bottle and refluxed for 30 h under argon protection. After the reaction was completed, the reaction solution was extracted with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was dried to obtain a crude product. The obtained crude product was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain 121 mg of a dimeric receptor material dialdehyde terminal precursor compound with a yield of 68%.

[0064] In the third step, a dimeric receptor material dialdehyde terminal precursor compound (110 mg, 0.03 mmol), difluorobiscyanoindanone (18 mg, 0.08 mmol) and 14 mL toluene were added to the reaction bottle, and 0.2 mL acetic anhydride and 0.4 mL boron trifluoride ether were added dropwise at room temperature under argon protection, and the reaction was carried out for 180 min. After the reaction was completed, the solvent was dried by spin drying, and the crude product was precipitated in methanol. The obtained solid was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1) to obtain a dimeric receptor material Dimer-4 (110 mg, yield 91%).

[0065] Example 5: Synthesis of Dimer-5

[0066]

[0067] In the first step, the dialdehyde terminal precursor SMA2 (500 mg, 0.34 mmol), 1,2-(5-bromo-6-fluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene) malononitrile (99 mg, 0.34 mmol) and 48 mL of chlorobenzene were added to the reaction bottle, and 0.3 mL of acetic anhydride and 0.4 mL of boron trifluoride ether were added dropwise at room temperature under argon protection, and the reaction was carried out for 30 minutes. After the reaction was completed, the solvent was dried, and the crude product was precipitated in methanol. The obtained solid was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain 343 mg of a unilateral precursor compound with a yield of 58%.

[0068] In the second step, a unilateral precursor compound (210 mg, 0.12 mmol), a 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 were added to a two-necked bottle and refluxed for 19 h under argon protection. After the reaction was completed, the reaction solution was extracted with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was dried to obtain a crude product. The obtained crude product was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1) to obtain 142 mg of a dimeric receptor material dialdehyde terminal precursor compound with a yield of 71%.

[0069] In the third step, the dialdehyde terminal precursor compound (140 mg, 0.04 mmol), dichlorobiscyanoindanone (26 mg, 0.10 mmol) and 16 mL toluene were added to the reaction bottle, and 0.3 mL acetic anhydride and 0.5 mL boron trifluoride ether were added dropwise under argon protection at room temperature, and the reaction was carried out for 600 min. After the reaction, the solvent was dried by spin drying, the crude product was precipitated in methanol, and the obtained solid was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1) to obtain the dimeric receptor material Dimer-5 (147 mg, yield 93%).

[0070] Example 6: Synthesis of Dimer-6

[0071]

[0072] In the first step, the dialdehyde terminal precursor SMA2 (500 mg, 0.34 mmol), 5-bromocyanoindanone (92 mg, 0.34 mmol) and 48 mL of chlorobenzene were added to the reaction bottle, and 0.3 mL of acetic anhydride and 0.5 mL of boron trifluoride ether were added dropwise at room temperature under argon protection, and the reaction was carried out for 30 minutes. After the reaction was completed, the solvent was dried by spin drying, and the crude product was precipitated in methanol. The obtained solid was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain 360 mg of the unilateral precursor compound with a yield of 61%.

[0073] In the second step, a unilateral precursor compound (210 mg, 0.12 mmol), a 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 were added to a two-necked bottle and refluxed for 18 h under argon protection. After the reaction was completed, the reaction solution was extracted with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was dried to obtain a crude product. The obtained crude product was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 3:1) to obtain 137 mg of a dimeric receptor material dialdehyde terminal precursor compound with a yield of 67%.

[0074] In the third step, a dimeric receptor material dialdehyde terminal precursor compound (140 mg, 0.04 mmol), difluorobiscyanoindanone (26 mg, 0.11 mmol) and 16 mL toluene were added to the reaction bottle, and 0.3 mL acetic anhydride and 0.5 mL boron trifluoride ether were added dropwise at room temperature under argon protection, and the reaction was carried out for 150 min. After the reaction was completed, the solvent was dried by spin drying, and the crude product was precipitated in methanol. The obtained solid was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain a dimeric receptor material Dimer-6 (139 mg, yield 90%).

[0075] Example 7: Synthesis of Dimer-7

[0076]

[0077] In the first step, the dialdehyde terminal precursor SMA2 (500 mg, 0.34 mmol), 5-bromocyanoindanone (92 mg, 0.34 mmol) and 48 mL of chlorobenzene were added to the reaction bottle, and 0.3 mL of acetic anhydride and 0.5 mL of boron trifluoride ether were added dropwise at room temperature under argon protection, and the reaction was carried out for 30 minutes. After the reaction was completed, the solvent was dried by spin drying, and the crude product was precipitated in methanol. The obtained solid was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain 360 mg of the unilateral precursor compound with a yield of 61%.

[0078] In the second step, a unilateral precursor compound (150 mg, 0.12 mmol), a 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 of toluene were added to a two-necked bottle and refluxed for 24 h under argon protection. After the reaction was completed, the reaction solution was extracted with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was dried to obtain a crude product. The obtained crude product was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain 101 mg of a dimeric receptor material dialdehyde terminal precursor compound with a yield of 64%.

[0079] In the third step, a dimeric receptor material dialdehyde terminal precursor compound (100 mg, 0.03 mmol), difluorobiscyanoindanone (18 mg, 0.08 mmol) and 15 mL toluene were added to the reaction bottle, and 0.4 mL acetic anhydride and 0.4 mL boron trifluoride ether were added dropwise at room temperature under argon protection, and the reaction was carried out for 200 min. After the reaction was completed, the solvent was dried by spin drying, and the crude product was precipitated in methanol. The obtained solid was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane = 4:1) to obtain a dimeric receptor material Dimer-6 (98 mg, yield 89%).

[0080] Example 8: Glass transition temperature test of dimer receptor material

[0081] The glass transition temperature test of the dimer receptor materials obtained in Examples 1 to 7 is performed as follows:

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

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

[0084]

[0085]

[0086] It can be seen from Table 1 that the glass transition temperatures of the dimer receptor materials Dimer-1 to Dimer-7 prepared in the above examples are increased and are not lower than 190°C.

[0087] Example 9: Device preparation of organic solar cells based on dimer acceptor materials

[0088] The dimer acceptor material obtained in Examples 1 to 7 was used as an active layer acceptor material to prepare an organic solar cell device. The specific preparation process is as follows:

[0089] The active layer solution (donor material and acceptor material in the same ratio, such as PM6: Dimer-1 = 1:1, solution concentration = 14 mg / mL) was spin-coated on the 2PACz-modified ITO glass substrate to prepare the photoactive layer. The active layer was thermally annealed (100 °C / 10 min) and then spin-coated with PDINN (concentration: 1.0 mg mL -1 The cathode was prepared by evaporating Ag.

[0090] Photovoltaic device performance: At AM 1.5G (100mW cm -2 ) irradiation, device performance and T 90 The lifespan (time to maintain 90% of the initial efficiency) is shown in Table 2 below, where V oc represents the 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 <![CDATA[V oc (V)]]> <![CDATA[J sc (V)]]> FF(%) PCE(%) <![CDATA[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] It can be seen from the above table that the organic solar cell device prepared by using the dimer type acceptor material prepared in the above embodiment as the active layer acceptor material has an open circuit voltage of ≥0.99V, T 90 When the time exceeds 1400 h, and especially when the time exceeds 2000 h, the photoelectric conversion efficiency is greater than 17%.

[0094] The description of the present invention is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the invention to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for particular uses.

Claims

1. A type of dimer-type receptor material based on electron-withdrawing bridging units, characterized in that: The subject The general structural formula of the bulk material is (I): Wherein, in (I), Ar is a rigid electron-withdrawing unit with a π-conjugated structure; R1, R2 and R3 are straight-chain 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.

2. A class of dimer-type receptor materials based on electron-withdrawing bridging units according to claim 1, It is characterized in that The Ar structural formula is one of (II): Wherein R is a H atom or a straight or branched alkyl group having 8 to 25 carbon atoms.

3. A class of dimer-type receptor materials based on electron-withdrawing bridging units according to claim 1, characterized in that: The glass transition temperature of the receptor material is ≥190°C.

4. A class of dimer-type receptor materials based on electron-withdrawing bridging units according to claim 1, characterized in that: The synthetic reaction equation of the receptor material is (III):

5. A method for preparing a type of dimer receptor material based on an electron-withdrawing bridging unit according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: (1) dissolving a dialdehyde substituted compound (a) and a Br-substituted indone compound (b) in an organic solvent at a molar ratio of 1:0.8-1.2, and adding acetic anhydride and boron trifluoride etherate to react for 30-90 minutes. After the reaction is completed, the organic solvent is dried and separated by column chromatography to obtain a unilateral precursor compound (c); (2) dissolving the unilateral 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, adding a catalyst, a ligand and cuprous iodide, reacting at 100-150° C. for 12-36 hours under an inert gas atmosphere, and after the reaction is completed, drying the organic solvent, and separating by column chromatography to obtain a dialdehyde precursor compound (e); (3) The dialdehyde precursor compound (e) prepared in step (2) and the indone compound (f) are dissolved in an organic solvent at a molar ratio of 1:2-4, acetic anhydride and boron trifluoride etherate are added to react for 30-600 minutes. After the reaction is completed, the organic solvent is dried and separated by column chromatography to obtain a dimer receptor material (g).

6. The preparation method according to claim 5, characterized in that: 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.

7. Use of a dimer receptor material based on an electron-withdrawing bridging unit according to any one of claims 1 to 4 in the preparation of optoelectronic functional devices.

8. The use according to claim 7, characterized in that: The optoelectronic functional device is an organic solar cell, wherein the dimer type acceptor material is used as an active layer acceptor material and is mixed with a donor material to prepare a photoactive layer of the organic solar cell.

9. The use according to claim 8, characterized in that: The photoactive layer has a thickness of 80 to 120 nm.

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