High-molecular-weight oligomeric receptor and preparation method thereof

Abstract

The invention relates to the technical field of organic photoelectric materials, in particular to a high-molecular-weight oligomeric receptor, a preparation method thereof and a photovoltaic device. The structural general formula of the high-molecular-weight oligomeric acceptor is any one of the following formulas; wherein the Y is as shown in the specification, the R1 is as shown in the specification, or the R2 is as shown in the specification; x is one of H, F, Cl, Br or I, and n is one of 0, 1, 2, 3, 4, 5, 6, 7 and 8; and m is one of 0, 2, 4, 6, 8, 10 and 12. The large-molecular-weight oligomeric receptor provided by the invention can inherit an ordered structure of a small-molecular receptor, can also significantly enhance the stability of receptor molecules in an active layer, and can finely regulate and control the molecular conformation, stacking arrangement, crystallization characteristics and the like of a tetrameric receptor by constructing a triune modification strategy of element-bridging unit-connecting site and the like.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic device technology, and in particular to a high molecular weight oligomer acceptor, its preparation method, and a photovoltaic device. Background Technology

[0002] Oligomers composed of multiple repeating units combine the advantages of small molecules and polymers, exhibiting benefits such as well-defined structure, good batch-to-batch reproducibility, excellent film-forming effect, low diffusion coefficient, good morphological stability, and high mechanical strength. Furthermore, as the molecular weight of the oligomeric acceptor increases, the resulting decrease in diffusion coefficient due to the increased glass transition temperature further enhances stability. However, the synthesis of high-molecular-weight oligomeric acceptors is limited in both quantity and type, and their synthesis faces significant raw material waste and cumbersome purification processes.

[0003] Currently, most oligomeric acceptors are constructed by connecting terminal groups with conjugated units. This introduces significant steric hindrance and torsion between the molecular backbones, while also reducing the density of halogens on the molecular skeleton. Consequently, it weakens the non-covalent interactions between molecules, affects the ordered stacking of molecules and charge transfer dynamics, and thus limits the further improvement of photovoltaic device efficiency.

[0004] Therefore, the existing technology still needs further improvement and enhancement. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a high molecular weight oligomer receptor that can inherit the ordered structure of small molecule receptors and significantly enhance the stability of receptor molecules in the active layer. At the same time, by constructing a three-in-one modification strategy of building motifs, bridging units, and connection sites, the molecular conformation, stacking arrangement, and crystallization properties of the tetramer receptor can be finely controlled.

[0006] To achieve this objective, the present invention adopts the following technical solution: Firstly, a high molecular weight oligomeric receptor, wherein its general structural formula is: , as well as Any one of them; Wherein, Y is R1 is , or R2 is , , or X is one of H, F, Cl, Br or I; n is one of 0, 1, 2, 3, 4, 5, 6, 7 or 8; m is one of 0, 2, 4, 6, 8, 10 or 12.

[0007] Secondly, a method for preparing the aforementioned high molecular weight oligomeric receptor, wherein the preparation method includes: The chemical structural formula is p-teCHO, chemical structural formula is IC-2X was mixed with chloroform and pyridine to obtain the first reaction mixture; The first reaction mixture is subjected to a first heat treatment to obtain a structure with the general formula: Large molecular weight oligomer receptors.

[0008] As a preferred technical solution, the method for preparing the high molecular weight oligomeric acceptor, wherein the preparation method of p-teCHO includes: The chemical structural formula is p-diCHO, chemical structural formula is TmAT-SnMe3, Pd2(dba)3 and P(o-tol)3 were mixed with toluene to obtain a second reaction mixture; The second reaction mixture was subjected to a second heat treatment to obtain the p-teCHO; Preferably, the heating temperature of the first heat treatment is 60-90℃ and the time is 12-24h; the heating temperature of the second heat treatment is 70-100℃ and the time is 12-24h.

[0009] As a preferred technical solution, the method for preparing the high molecular weight oligomeric acceptor, wherein the preparation method of p-diCHO includes: The chemical structural formula is BTP-R1, chemical structural formula is p-dnBrPh, chemical structural formula is Br-R2, carbonate, N,N dimethylformamide, and POCl3 were reacted to give a third reaction mixture; The third reaction mixture is subjected to a third heat treatment to obtain the p-diCHO; Preferably, the heating temperature of the third heating treatment is 50-70℃, and the time is 12-24h.

[0010] Thirdly, a method for preparing the aforementioned high molecular weight oligomeric receptor, wherein the preparation method includes: The chemical structural formula is m-teCHO, chemical structural formula is IC-2X was mixed with chloroform and pyridine to give a fourth reaction mixture; The fourth reaction mixture is subjected to a fourth heat treatment to obtain a structure with the general formula: Large molecular weight oligomer receptors.

[0011] As a preferred technical solution, the method for preparing the high molecular weight oligomeric acceptor, wherein the method for preparing m-teCHO includes: The chemical structural formula is m-diCHO, chemical structural formula is TmAT-SnMe3, Pd2(dba)3, and P(o-tol)3 were mixed with toluene to obtain the fifth reaction mixture; The fifth reaction mixture is subjected to a fifth heat treatment to obtain the m-teCHO; Preferably, the heating temperature of the fourth heating treatment is 60-90℃ and the time is 12-24h; the heating temperature of the fifth heating treatment is 70-100℃ and the time is 12-24h.

[0012] As a preferred technical solution, the method for preparing the high molecular weight oligomeric acceptor, wherein the preparation method of m-diCHO includes: The chemical structural formula is BTP-R1, chemical structural formula is The chemical structural formula of m-dnBrPh is as follows: Br-R2, carbonate, N,N dimethylformamide, and POCl3 were reacted to give a sixth reaction mixture; The sixth reaction mixture was subjected to a sixth heating treatment to obtain the m-diCHO; Preferably, the heating temperature of the sixth heating treatment is 50-70℃, and the time is 12-24h.

[0013] Fourthly, a method for preparing the aforementioned high molecular weight oligomeric receptor, wherein the preparation method includes: The chemical structural formula is o-teCHO, chemical structural formula is IC-2X was mixed with chloroform and pyridine to give the seventh reaction mixture; The seventh reaction mixture is subjected to a seventh heat treatment to obtain a structure with the general formula: Large molecular weight oligomer receptors.

[0014] As a preferred technical solution, the method for preparing the high molecular weight oligomeric acceptor, wherein the method for preparing o-teCHO includes: The chemical structural formula is o-diCHO, chemical structural formula is TmAT-SnMe3, Pd2(dba)3 and P(o-tol)3 were mixed with toluene to obtain the eighth reaction mixture; The eighth reaction mixture is subjected to an eighth heat treatment to obtain the o-teCHO; Preferably, the heating temperature of the seventh heating treatment is 60-90℃ and the time is 12-24h; the heating temperature of the eighth heating treatment is 70-100℃ and the time is 12-24h.

[0015] As a preferred technical solution, the method for preparing the high molecular weight oligomeric acceptor, wherein the preparation method of o-diCHO includes: The chemical structural formula is BTP-R1, chemical structural formula is o-dnBrPh, chemical structural formula is Br-R2, carbonate, N,N dimethylformamide, and POCl3 were reacted to give the ninth reaction mixture; The ninth reaction mixture is subjected to a ninth heating treatment to obtain the o-diCHO; Preferably, the heating temperature of the ninth heating treatment is 50-70℃, and the time is 12-24h.

[0016] Fifthly, a photovoltaic device, comprising: a substrate; a heterojunction structure disposed on the substrate, the heterojunction structure comprising a polymer donor and a high molecular weight oligomer acceptor according to claim 1; wherein the heterojunction structure is a blend layer formed by the polymer donor and the high molecular weight oligomer acceptor; or The polymer donor layer and the oligomer acceptor layer are stacked together, wherein the polymer donor layer contains the polymer donor and the oligomer acceptor layer contains the high molecular weight oligomer acceptor.

[0017] Beneficial effects: Compared with the prior art, the high molecular weight oligomer receptor provided by the present invention can inherit the ordered structure of small molecule receptors and significantly enhance the stability of receptor molecules in the active layer. At the same time, through the construction of a three-in-one modification strategy of building motifs-bridging units-connection sites, the molecular conformation, stacking arrangement, crystallization characteristics of tetramer receptors can be finely controlled. Attached Figure Description

[0018] Figure 1 This is the temperature-dependent absorption spectrum of diYCl in dilute chlorobenzene solution.

[0019] Figure 2 This is the temperature-dependent absorption spectrum of teYCl in dilute chlorobenzene solution.

[0020] Figure 3 This is the temperature-dependent absorption spectrum of pYCl in dilute chlorobenzene solution.

[0021] Figure 4 The absorption spectra of diYCl, teYCl, and pYCl in dilute chloroform solution are shown.

[0022] Figure 5 The images show the absorption spectra of diYCl, teYCl, and pYCl in solid thin films.

[0023] Figure 6 Electrochemical cyclic voltammetry curves for diYCl, teYCl, and pYCl.

[0024] Figure 7 The J (current)-V (voltage) curves of quasi-planar heterojunction photovoltaic devices with diYCl, teYCl, and pYCl are shown.

[0025] Figure 8 The graph shows the storage stability test results for diYCl, teYCl, and pYCl.

[0026] Figure 9 The graph shows the photostability test results for diYCl, teYCl, and pYCl.

[0027] Figure 10 The graph shows the thermal stability test results for diYCl, teYCl, and pYCl. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The invention will now be described in detail with reference to the embodiments. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0029] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. Furthermore, it should be understood that when the terms "comprising" and / or "package" are used in this specification… When "includes", it indicates the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0031] This invention provides a high molecular weight oligomeric receptor, the general structural formula of which is: , as well as Any one of them; Wherein, Y is R1 is , or R2 is , , or X is one of H, F, Cl, Br or I; n is one of 0, 1, 2, 3, 4, 5, 6, 7 or 8; m is one of 0, 2, 4, 6, 8, 10 or 12.

[0032] In this embodiment, introducing halogens into the structure not only modulates the energy level distribution and light absorption characteristics of the electron acceptor, but also improves molecular stacking and crystallization properties, thus making it easier to obtain active layer materials and solar cells with good photoelectric performance. When n and m are both very small, the acceptor material has insufficient solubility and severe molecular self-aggregation, which is not conducive to obtaining an active layer with good morphology. Therefore, n and m need to be gradually increased to regulate the solubility of acceptor molecules and their stacking arrangement in the blend film. However, n and m cannot be too large, because introducing a large number of non-conjugated alkyl chains will inevitably reduce the charge transport characteristics of the electron acceptor.

[0033] In this embodiment, the high molecular weight oligomeric acceptor exhibits good crystallinity and, when matched with the polymer donor (such as D18), can form a stable and ideal active layer, while also possessing enhanced exciton dynamics and charge transport characteristics. The organic photovoltaic cell prepared based on this exhibits superior performance, such as an energy conversion efficiency exceeding 18%. Furthermore, it retains over 80% of its initial efficiency after being stored at 65°C for 5000 hours and after continuous exposure to standard sunlight for 3000 hours.

[0034] Based on the same inventive concept, embodiments of the present invention also provide a method for preparing a high molecular weight oligomeric receptor, the method comprising: mixing p-teCHO / m-teCHO / o-teCHO, IC-2X with chloroform and pyridine in an inert atmosphere, and sequentially performing alkylation, formylation, Stille coupling, Knoevenagel condensation and other reaction steps to obtain a high molecular weight oligomeric receptor.

[0035] Based on the same inventive concept, embodiments of the present invention also provide a photovoltaic device, which includes a bulk heterojunction or a quasi-planar heterojunction. The bulk heterojunction is formed by depositing a mixture of a polymer donor and a high molecular weight oligomer acceptor onto a substrate. The quasi-planar heterojunction structure is formed by first depositing a polymer donor onto a substrate to form a polymer donor film, and then depositing a high molecular weight oligomer acceptor onto the polymer donor film to form an oligomer film. The high molecular weight oligomer acceptor is the high molecular weight oligomer acceptor described in the present invention.

[0036] As an example, the molecular structure of the polymer donor is: or or Wherein, n is a natural number greater than or equal to 5, the number-average molecular weight of the donor is 38,000-100,000, the weight-average molecular weight is 600,000-500,000, and the dispersion is 1.8-4.3.

[0037] The following specific preparation examples will further explain and illustrate the high molecular weight oligomeric receptor and its preparation method provided by the present invention.

[0038] Example 1 Synthesis steps of p-teYCl-DT: 1. The synthesis reaction process of p-diCHO-DT is as follows:

[0039] Its preparation methods include: BTP-C11 (300 mg, 0.40 mmol, 1.00 equiv.), K2CO3 (276 mg, 2.00 mmol), KI (0.10 g, 0.60 mmol, 1.50 equiv.), and p-d6BrPh (147 mg, 0.20 mmol, 0.50 equiv.) were added to a dried round-bottom flask equipped with a magnetic stir bar. The flask was evacuated and filled with argon several times. Then, NN dimethylformamide (20 mL) was added to the flask, and the reaction mixture was stirred at 80 °C for 12 hours. Then, 2-decyltetradecyl bromide (1.68 g, 4.02 mmol, 10.00 equiv.) was added, and the reaction mixture was stirred at 80 °C for another 24 hours. The organic solvent was removed under vacuum, and then POCl3 (1 mL), N,N dimethylformamide (5 mL), and dichloromethane (20 mL) were added to the flask to obtain the seventh reaction mixture. The seventh reaction mixture was stirred at 40 °C for 12 hours. TLC was used to detect the reaction (petroleum ether:dichloromethane volume ratio = 1:1). The reaction mixture was cooled to room temperature and poured into water. After thorough mixing, it was extracted with petroleum ether, and the organic phase was dried over anhydrous magnesium sulfate. The organic solvent was removed under vacuum. The obtained reaction mixture was further purified by rapid silica gel column chromatography (petroleum ether:dichloromethane volume ratio = 1:1) to obtain p-diCHO-DT (673 mg, 58%) as an orange-yellow solid. 1H NMR (400 MHz, Chloroform-d) δ 10.13(d, J = 1.1 Hz, 2H), 10.11 (s, 2H), 7.01 (d, J = 2.7 Hz, 1H), 6.77-6.65 (m,2H), 4.70-4.57 (m, 8H), 3.82 (t, J = 6.4 Hz, 2H), 3.75 (t, J = 6.5 Hz, 2H), 3.16 (td, J = 7.8, 4.9 Hz, 8H), 1.91 (m, 16H), 1.80-0.50 (m, 210H). 2. The synthesis reaction process of p-teCHO-DT is as follows:

[0040] Its preparation methods include: p-diCHO-DT (114 mg, 0.04 mmol, 1.00 equiv.), T10AT-SnMe3 (12.6 mg, 0.02 mmol, 0.50 equiv.), Pd2(dba)3 (1.95 mg, 0.002 mmol, 0.05 equiv.), and P(o-tol)3 (5.08 mg, 0.02 mmol, 0.50 equiv.) were added to a dried round-bottom flask equipped with a magnetic stir bar. The flask was evacuated and filled with argon gas, and this process was repeated several times. Toluene (5 mL) was then added to the flask to obtain a fourth reaction mixture. The fourth reaction mixture was stirred at 110 °C for 8 hours. TLC was used to detect the reaction (petroleum ether:dichloromethane volume ratio = 2:3). The reaction mixture was cooled to room temperature, poured into water, and extracted with dichloromethane. The organic phase was dried over anhydrous magnesium sulfate, and the organic solvent was removed under vacuum. The resulting reaction mixture was further purified by rapid silica gel column chromatography (petroleum ether:dichloromethane, volume ratio = 2:3) to give p-teCHO-DT (74.8 mg, 64%) as an orange-yellow solid. ¹H NMR (400 MHz, Chloroform-d) δ 10.10 (m, 8H), 7.19 (d, J = 3.6 Hz, 2H), 7.02 (d, J = 3.0 Hz, 2H), 6.70 (m, 2H), 6.61 (m, 4H), 4.64 (m, 16H), 3.80 (m, 8H), 3.21–3.08 (m, 16H), 2.67 (m, 4H), 1.90 (m, 32H), 1.75–0.54 (m, 436H). 3. The synthesis reaction process of p-teYCl-DT is as follows:

[0041] The preparation method includes: adding p-teCHO-DT (74.8 mg, 0.013 mmol, 1.00 equiv.) and IC-2Cl (40.3 mg, 0.15 mmol, 11.50 equiv.) to a dried round-bottom flask equipped with a magnetic stir bar. The flask was evacuated and filled with argon gas, repeated several times. Then, pyridine (0.5 mL) and chloroform (20 mL) were added to the flask to obtain the first reaction mixture. The first reaction mixture was stirred at 60 °C for 12 hours. TLC was used to detect the reaction (petroleum ether:chloroform volume ratio = 1:1). After cooling the reaction mixture to room temperature, it was concentrated to approximately 10 mL and methanol (100 mL) was added. The mixture was filtered, and the resulting reaction mixture was further purified by rapid silica gel column chromatography (petroleum ether:chloroform volume ratio = 1:1) to obtain a blue-black solid p-teYCl-DT (76.9 mg, 77%). 1H NMR (400 MHz, Chloroform-d) δ 8.85-8.37 (m, 16H),7.85-7.70 (m, 8H), 7.24 (d, J = 4.2 Hz, 4H), 7.06 (s, 2H), 6.78-6.57 (m, 6H),4.64 (m, 16H), 3.88 (m, 8H), 2.87 (m, 16H), 2.53 (s, 8H), 2.09-1.74 (m, 32H), 1.57-0.64 (m, 436H). HR-MS (MALDI-TOF) m / z calculation (C446H488Cl16N32O12S22): 7820.01. The value was measured to be 7820.0500.

[0042] Comparative Example 1 The synthesis steps of p-diYCl-DT in this comparative example are as follows: 1. The synthesis reaction process of p-diCHO-DT-HH is as follows:

[0043] The preparation method includes: adding BTP-C11 (300 mg, 0.40 mmol, 1.00 equivalent), K2CO3 (276 mg, 2.00 mmol, 5.00 equivalent), KI (0.10 g, 0.60 mmol, 1.50 equivalent), and p-d6BrPh-HH (132 mg, 0.20 mmol, 0.50 equivalent) to a dried round-bottom flask equipped with a magnetic stir bar. The flask is evacuated and filled with argon gas, repeated several times. Then, NN dimethylformamide (20 mL) is added to the flask, and the reaction mixture is stirred at 80 °C for 12 hours. Next, 2-decyltetradecyl bromide (1.68 g, 4.02 mmol, 10.00 equivalent) is added, and the reaction mixture is stirred at 80 °C for another 24 hours. The organic solvent was removed under vacuum, and then POCl3 (1 mL), N,N dimethylformamide (5 mL), and dichloromethane (20 mL) were added to the flask to obtain a reaction mixture. The reaction mixture was stirred at 40 °C for 12 hours. TLC was used to detect the reaction (petroleum ether:dichloromethane volume ratio = 1:1). After cooling the reaction mixture to room temperature, it was poured into water, thoroughly mixed, and extracted with petroleum ether. The organic phase was dried over anhydrous magnesium sulfate, and the organic solvent was removed under vacuum. The obtained reaction mixture was further purified by rapid silica gel column chromatography (petroleum ether:dichloromethane volume ratio = 1:1) to obtain an orange-yellow solid p-diCHO-DT (673 mg, 61%). 1H NMR (400 MHz, Chloroform-d) δ 10.14(s, 4H), 6.74 (s, 4H), 4.76-4.49 (m, 8H), 3.77 (m, 4H), 3.19 (d, J = 6.9 Hz,8H), 1.93 (m, 16H), 1.68-0.65 (m, 210H). 2. The synthesis reaction process of p-diYCl-DT is as follows:

[0044] The preparation method includes: adding p-diCHO-DT-HH (200 mg, 0.07 mmol, 1.00 equiv.) and IC-2Cl (114 mg, 0.43 mmol, 6.00 equiv.) to a dried round-bottom flask equipped with a magnetic stir bar. The flask was evacuated and filled with argon gas, repeated several times. Then, pyridine (0.5 mL) and chloroform (20 mL) were added to the flask to obtain the first reaction mixture. The first reaction mixture was stirred at 60 °C for 12 hours. TLC was used to detect the reaction (petroleum ether:chloroform volume ratio = 1:1). After cooling the reaction mixture to room temperature, it was concentrated to approximately 10 mL and methanol (100 mL) was added. The mixture was filtered, and the resulting reaction mixture was further purified by rapid silica gel column chromatography (petroleum ether:chloroform volume ratio = 1:1) to obtain a blue-black solid p-diYCl-DT (221 mg, 82%). 1H NMR (400 MHz, Chloroform-d) δ 8.87-8.56 (m, 6H), 8.50(s, 2H), 7.78 (d, J = 21.0 Hz, 4H), 6.81 (s, 4H), 4.63 (m, 8H), 3.91 (t, J =6.5 Hz, 4H), 2.86 (m, 8H), 2.52 (s, 4H), 2.09-1.80 (m, 12H), 1.77-1.56 (m, 24H), 1.44-0.67 (m, 184H). Comparative Example 2 The synthesis steps of p-pYCl-DT in this comparative example are as follows: 1. The synthesis reaction process of p-diCHO-DT-BrBr is as follows:

[0045] The preparation method includes: adding BTP-C11 (300 mg, 0.40 mmol, 1.00 equiv.), K2CO3 (276 mg, 2.00 mmol, 5.00 equiv.), KI (0.10 g, 0.60 mmol, 1.50 equiv.), and p-d6BrPh-BrBr (163 mg, 0.20 mmol, 0.50 equiv.) to a dried round-bottom flask equipped with a magnetic stir bar. The flask is evacuated and filled with argon gas, repeated several times. Then, NN dimethylformamide (20 mL) is added to the flask, and the reaction mixture is stirred at 80 °C for 12 hours. Next, 2-decyltetradecyl bromide (1.68 g, 4.02 mmol, 10.00 equiv.) is added, and the reaction mixture is stirred at 80 °C for another 24 hours. The organic solvent was removed under vacuum, and then POCl3 (1 mL), N,N dimethylformamide (5 mL), and dichloromethane (20 mL) were added to the flask to obtain a reaction mixture. The reaction mixture was stirred at 40 °C for 12 hours. TLC was used to detect the reaction (petroleum ether:dichloromethane volume ratio = 1:1). After cooling the reaction mixture to room temperature, it was poured into water, thoroughly mixed, and extracted with petroleum ether. The organic phase was dried over anhydrous magnesium sulfate, and the organic solvent was removed under vacuum. The obtained reaction mixture was further purified by rapid silica gel column chromatography (petroleum ether:dichloromethane volume ratio = 1:1) to obtain an orange-yellow solid p-diCHO-DT (705 mg, 60%). 1H NMR (400 MHz, Chloroform-d) δ 10.13(s, 4H), 7.05 (s, 2H), 4.62 (m, 8H), 3.91 (t, J = 6.5 Hz, 4H), 3.18 (t, J =7.8 Hz, 8H), 2.05 (m, 2H), 1.90 (m, 12H), 1.81-1.72 (m, 4H), 1.50-0.77 (m, 208H). 2. The synthesis reaction process of p-mpYCl-DT is as follows:

[0046] The preparation method includes: adding p-diCHO-DT-BrBr (600 mg, 0.20 mmol, 1.00 equiv.) and IC-2Cl (323 mg, 1.23 mmol, 6.00 equiv.) to a dried round-bottom flask equipped with a magnetic stir bar. The flask was evacuated and filled with argon gas, repeated several times. Then, pyridine (0.5 mL) and chloroform (20 mL) were added to the flask to obtain the first reaction mixture. The first reaction mixture was stirred at 60 °C for 12 hours. TLC was used to detect the reaction (petroleum ether:chloroform volume ratio = 1:1). After cooling the reaction mixture to room temperature, it was concentrated to approximately 10 mL and methanol (100 mL) was added. The mixture was filtered, and the resulting reaction mixture was further purified by rapid silica gel column chromatography (petroleum ether:chloroform volume ratio = 1:1) to obtain a blue-black solid, p-mpYCl-DT (704 mg, 88%). 1H NMR (400 MHz, Chloroform-d) δ 8.80-8.58 (m, 6H), 8.52(m, 2H), 7.77 (d, J = 23.3 Hz, 4H), 7.08 (s, 2H), 4.62 (d, J = 70.7 Hz, 8H), 3.99 (d, J = 8.3 Hz, 4H), 2.86 (m, 8H), 2.50 (s, 4H), 2.29-1.61 (m, 28H), 1.54-0.61 (m, 194H). 3. The synthesis reaction process of p-pYCl-DT is as follows:

[0047] The preparation method includes adding p-mpYCl-DT (118 mg, 0.03 mmol, 1.00 equivalent), T10AT-SnMe3 (18.9 mg, 0.03 mmol, 1.00 equivalent), Pd2(dba)3 (5.85 mg, 0.006 mmol, 0.05 equivalent), and P(o-tol)3 (15.24 mg, 0.05 mmol, 0.50 equivalent) to a dried round-bottom flask equipped with a magnetic stir bar. The flask was evacuated and filled with argon gas, repeated several times. Toluene (5 mL) was then added to the flask to obtain the reaction mixture. The resulting reaction mixture was stirred at 110 °C for 8 hours. After cooling the reaction mixture to room temperature, the solvent was removed under vacuum. The solid mixture was then poured into chloroform (10 mL) until all solids dissolved, followed by the addition of methanol. The precipitate was subjected to Soxhlet extraction sequentially with methanol, dichloromethane, and chloroform. The chloroform solution of the product was concentrated to approximately 10 mL and methanol (100 mL) was added. The mixture was filtered, the precipitate was collected, and dried under vacuum overnight to obtain a dark blue solid p-pYCl-DT (84.1 mg, 69%). GPC: Mn = 12.7 kDa, Mw = 17.9 kDa, PDI = 1.41.

[0048] Experimental Example 1 The p-teYCl-DT prepared in this invention was subjected to UV-Vis absorption testing: The absorption spectra of p-teYCl-DT in chlorobenzene solution within the temperature range of 25-100℃ were measured using a UV-Vis spectrophotometer. Then, its absorption spectra in chloroform solution and in thin film were measured. The optical band gap was calculated using the empirical formula (Egopt=1240 / λonset film), where λonset film is the absorption sideband of the absorption spectrum of the material in thin film state. Figure 1 The absorption spectrum of p-diYCl-DT in chlorobenzene solution is shown in the temperature range of 25-100℃. Figure 2 The absorption spectrum of p-teYCl-DT in chlorobenzene solution is shown in the temperature range of 25-100℃. Figure 3 This is the absorption spectrum of p-pYCl-DT in chlorobenzene solution within the temperature range of 25-100℃. Figures 1 to 3 It can be seen that in chlorobenzene solution, the absorbance of the absorption peaks for internal charge transfer of the three molecules decreases only slightly with increasing temperature, accompanied by a slight blue shift, indicating limited intramolecular relaxation during heating. Simultaneously, an additional peak appears near 710 nm for all three molecules; the intensity of this additional peak gradually decreases with increasing molecular weight. This phenomenon is mainly attributed to the h-aggregation behavior within the acceptor molecule, and shows a gradual decreasing trend during heating. Figure 4The absorption spectra of p-diYCl-DT, p-teYCl-DT, and p-pYCl-DT in chloroform solution are shown. Figure 4 It can be seen that the absorption spectra of the three receptors in dilute solutions show great similarity. Figure 5 The images show the absorption spectra of p-diYCl-DT, p-teYCl-DT, and p-pYCl-DT in thin film form. Figure 5 As can be seen, the absorption spectrum of the acceptor material exhibits a blue shift with the increase of repeating units. During film formation, the size of the acceptors may hinder their initial stacking behavior. With increasing molecular size, the flexibility of molecular arrangement decreases, subsequently leading to a blue shift in the film absorption spectrum. The corresponding data are listed in Table 1.

[0049] Table 1 Physicochemical properties of electron acceptors

[0050] Experiment Example 2 Electrochemical tests were performed on the p-diYCl-DT, p-teYCl-DT, and p-pYCl-DT prepared in this invention, including the calculation of the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), and band gap (Eg) of p-diYCl-DT, p-teYCl-DT, and p-pYCl-DT. The p-diYCl-DT, p-teYCl-DT, and p-pYCl-DT were dissolved in chloroform to prepare solutions of 1 mg / mL, and uniformly dropped onto the working electrode to form a thin film with a diameter of approximately 2 mm (covering the working electrode). A 0.1 M tetrabutylammonium hexafluorophosphate solution in acetonitrile (20 mL) was used as the electrolyte, with platinum wire as the control electrode, Ag / Ag+ as the reference electrode, and ferrocene as the standard. The redox potentials were measured using cyclic voltammetry on an electrochemical workstation, and the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), and band gap (Eg) were then calculated.

[0051] EHOMO = -e (EOX + 4.36) (eV) ELUMO = -e (Ered + 4.36) (eV) The HOMO and LUMO energy level distributions of p-diYCl-DT, p-teYCl-DT, and p-pYCl-DT are as follows: Figure 6 As shown, the LUMO energy level gradually increases with the increase of the acceptor molecular weight, thus achieving a higher open-circuit voltage in organic photovoltaic devices. The corresponding data are listed in Table 1.

[0052] Experimental Example 3 The p-diYCl-DT, p-teYCl-DT, and p-pYCl-DT prepared in this invention were used as acceptors in quasi-planar heterojunction organic photovoltaic devices. After fabrication, the devices were tested for performance. The indium tin oxide (ITO) glass substrate was first cleaned sequentially with deionized water, acetone, and isopropanol to ensure surface cleanliness. After drying overnight in a vacuum oven at 90°C, it was UV treated for 25 minutes to improve surface hydrophilicity. The PEDOT:PSS film was spin-coated onto the ITO at 6000 rpm for 30 seconds, followed by annealing on a hot plate at 150°C for 10 minutes. For the active layer of the quasi-planar heterojunction device structure, a two-step method was used. First, the donor polymer D18 was dissolved in a solution with a concentration of 7 mg / mL... -1 The substrate was coated with a CB solution and then, without annealing, by rotating at 3000 rpm for 35 seconds. The acceptor material was dissolved in chloroform at a concentration of 9 mg / mL, and 0.5% (v / v) CN (1-chloronaphthalene) was added to the solution as an additive. The acceptor layer was coated by rotating at 3000 rpm for 35 seconds, and then heated at 100 °C for 10 minutes. A PDINN cathode interface layer was deposited using a methanol solution at a concentration of 1 mg / mL. Finally, a 100 nm silver cathode was deposited using a thermal evaporator to complete the fabrication of the quasi-planar heterojunction device. The photoelectric conversion efficiency of the organic solar cell was measured in a nitrogen-filled glove box using a solar simulator AM 1.5G (illuminance 100 Mwcm). -2 The measurements were taken from standard silicon cells (4 cm⁻¹) and certified by the National Renewable Energy Laboratory (NREL). 2 Calibration was performed. The open-circuit voltage (VOC), short-circuit current (JSC), fill factor (FF), and power conversion efficiency (PCE) of quasi-planar heterojunction devices fabricated from p-diYCl-DT, p-teYCl-DT, p-pYCl-DT, and D18 were tested. The results are shown in Table 2. Figure 7 The current-voltage (JV) curves for D18 and p-diYCl-DT, p-teYCl-DT, and p-pYCl-DT quasi-planar heterojunction devices are shown. As the molecular LUMO energy level increases, the corresponding open-circuit voltage also increases. The device based on D18 / p-teYCl-DT achieved the highest efficiency of 18.02%, due to its higher short-circuit current density and higher fill factor. This indicates that the tetramer has better charge transport capabilities compared to the dimer and polymer. Small molecule tetramerization is a very promising method for improving the photovoltaic performance of devices.

[0053] Table 2 Parameters of Quasi-planar Heterojunction Devices

[0054] Experiment Example 4 The quasi-planar heterojunction devices D18 / p-diYCl-DT, D18 / p-teYCl-DT, and D18 / p-pYCl-DT of this invention were tested for optical stability, thermal stability, and storage stability in a nitrogen-filled glove box without encapsulation to assess their stability. The results of the storage stability are as follows: Figure 8 As shown, the results of illumination stability are as follows: Figure 9 As shown, the results of thermal stability are as follows: Figure 10 As shown, the device based on D18 / p-teYCl-DT retained 98.3% of its initial PCE after 3500 hours of storage, demonstrating excellent stability. In contrast, under the same storage conditions, devices based on D18 / p-diYCl-DT and D18 / p-pYCl-DT retained over 91.1% and 80.0% of their initial conversion efficiencies, respectively. After 3000 hours of illumination, only the device based on D18 / p-teYCl-DT retained over 80% of its initial PCE; in contrast, the T80 lifetimes of D18 / p-diYCl-DT and D18 / p-pYCl-DT under illumination were 2070 hours and 1200 hours, respectively. The thermal stability of the three acceptors showed significant variations. The device based on D18 / p-teYCl-DT retained 86.6% of its initial PCE after 1865 hours of storage at 65°C. In contrast, the device based on D18 / p-diYCl-DT retained 66.1% of its initial PCE after 1300 hours of storage under the same conditions. In contrast, the device based on D18 / p-pYCl-DT retained only 80% after just 60 hours of storage, indicating lower thermal stability. Notably, the quasi-planar heterojunction device based on p-teYCl-DT exhibited excellent device stability. This enhanced stability can be attributed to the well-defined chemical structure and increased molecular size, which effectively restricts molecular diffusion, thus contributing to the device's superior stability.

[0055] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A high molecular weight oligomeric receptor, characterized in that, Its general structural formula is , as well as Any one of them; Wherein, Y is R1 is , or R2 is , , or X is one of H, F, Cl, Br or I; n is one of 0, 1, 2, 3, 4, 5, 6, 7 or 8; m is one of 0, 2, 4, 6, 8, 10 or 12.

2. A method for preparing the high molecular weight oligomeric receptor according to claim 1, characterized in that, The preparation method includes: The chemical structural formula is p-teCHO, chemical structural formula is IC-2X was mixed with chloroform and pyridine to obtain the first reaction mixture; The first reaction mixture is subjected to a first heat treatment to obtain a structure with the general formula: Large molecular weight oligomer receptors.

3. The method for preparing high molecular weight oligomeric acceptors according to claim 2, characterized in that, The preparation method of the p-teCHO includes: The chemical structural formula is p-diCHO, chemical structural formula is TmAT-SnMe3, Pd2(dba)3 and P(o-tol)3 were mixed with toluene to obtain a second reaction mixture; The second reaction mixture was subjected to a second heat treatment to obtain the p-teCHO; The preparation method of the p-diCHO includes: The chemical structural formula is BTP-R1, chemical structural formula is p-dnBrPh, chemical structural formula is Br-R2, carbonate, N,N dimethylformamide, and POCl3 were reacted to give a third reaction mixture; The third reaction mixture is subjected to a third heat treatment to obtain the p-diCHO; Preferably, the heating temperature of the third heat treatment is 50-70℃. Preferably, the heating temperature of the first heat treatment is 60-90℃; the heating temperature of the second heat treatment is 70-100℃.

4. A method for preparing the high molecular weight oligomeric receptor according to claim 1, characterized in that, The preparation method includes: The chemical structural formula is m-teCHO, chemical structural formula is IC-2X was mixed with chloroform and pyridine to give a fourth reaction mixture; The fourth reaction mixture is subjected to a fourth heat treatment to obtain a structure with the general formula: Large molecular weight oligomer receptors.

5. The method for preparing high molecular weight oligomeric receptors according to claim 4, characterized in that, The preparation method of the m-teCHO includes: The chemical structural formula is m-diCHO, chemical structural formula is TmAT-SnMe3, Pd2(dba)3, and P(o-tol)3 were mixed with toluene to obtain the fifth reaction mixture; The fifth reaction mixture is subjected to a fifth heat treatment to obtain the m-teCHO; Preferably, the heating temperature of the fourth heating treatment is 60-90℃; the heating temperature of the fifth heating treatment is 70-100℃.

6. The method for preparing high molecular weight oligomeric acceptors according to claim 5, characterized in that, The preparation method of the m-diCHO includes: The chemical structural formula is BTP-R1, chemical structural formula is The chemical structural formula of m-dnBrPh is as follows: Br-R2, carbonate, N,N dimethylformamide, and POCl3 were reacted to give a sixth reaction mixture; The sixth reaction mixture was subjected to a sixth heating treatment to obtain the m-diCHO; Preferably, the heating temperature of the sixth heat treatment is 50-70℃.

7. A method for preparing the high molecular weight oligomeric receptor according to claim 1, characterized in that, The preparation method includes: The chemical structural formula is o-teCHO, chemical structural formula is IC-2X was mixed with chloroform and pyridine to give the seventh reaction mixture; The seventh reaction mixture is subjected to a seventh heat treatment to obtain a structure with the general formula: Large molecular weight oligomer receptors.

8. The method for preparing high molecular weight oligomeric acceptors according to claim 7, characterized in that, The preparation method of the o-teCHO includes: The chemical structural formula is o-diCHO, chemical structural formula is TmAT-SnMe3, Pd2(dba)3 and P(o-tol)3 were mixed with toluene to obtain the eighth reaction mixture; The eighth reaction mixture is subjected to an eighth heat treatment to obtain the o-teCHO; Preferably, the heating temperature of the seventh heat treatment is 60-90℃; the heating temperature of the eighth heat treatment is 70-100℃.

9. The method for preparing high molecular weight oligomeric acceptors according to claim 8, characterized in that, The preparation method of the o-diCHO includes: The chemical structural formula is BTP-R1, chemical structural formula is o-dnBrPh, chemical structural formula is Br-R2, carbonate, N,N dimethylformamide, and POCl3 were reacted to give the ninth reaction mixture; The ninth reaction mixture is subjected to a ninth heating treatment to obtain the o-diCHO; Preferably, the heating temperature of the ninth heat treatment is 50-70°C.

10. A photovoltaic device, characterized in that, include: A substrate, a heterojunction structure disposed on the substrate, the heterojunction structure comprising a polymer donor and a high molecular weight oligomer acceptor according to claim 1; wherein the heterojunction structure is a blend layer formed by the polymer donor and the high molecular weight oligomer acceptor; or The polymer donor layer and the oligomer acceptor layer are stacked together, wherein the polymer donor layer contains the polymer donor and the oligomer acceptor layer contains the high molecular weight oligomer acceptor.

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