A non-fullerene acceptor material, its preparation method and application

Abstract

This invention discloses a non-fullerene acceptor material, its preparation method, and its applications. The non-fullerene acceptor material has the structure shown in Formula Ia. The non-fullerene acceptor material provided by this invention has a non-fused tri(hetero)aromatic ring core structure. This tri(hetero)aromatic ring backbone is coplanar. Furthermore, by utilizing the multi-selectivity and combination of the tri(hetero)aromatic rings, organic photovoltaic material molecules can be flexibly constructed, extending the light absorption range to the near-infrared region, which is beneficial for the development of novel, highly efficient acceptor and donor materials.

Description

Technical Field

[0001] This invention relates to a non-fullerene receptor material, its preparation method and application, specifically to a novel type of receptor material with a non-fused ring backbone, its preparation method and application. Background Technology

[0002] To address the increasingly acute energy problem, the scientific and efficient utilization of clean energy sources such as solar energy has become an important research topic. Organic solar cells, as one of the effective ways to utilize solar energy, have the advantages of being lightweight, flexible, and easy to process, and have gradually attracted the attention of the scientific and industrial communities in recent years.

[0003] With the design and application of new organic photovoltaic materials, the efficiency of organic solar cell devices has been rapidly improved. The best efficiency of a single organic solar cell has exceeded 18%, demonstrating its bright application prospects.

[0004] Non-fullerene small molecule acceptor materials are currently the most efficient acceptor materials in the field, and novel molecular structure designs are constantly emerging. To overcome the shortcomings of traditional fused-ring non-fullerene acceptor materials, such as cumbersome synthesis processes and insufficient flexibility in structural adjustment, non-fused-ring acceptor materials have been gradually designed, synthesized, and attempted to be used in the construction of high-efficiency organic solar cell devices in recent years.

[0005] These types of non-fused-ring acceptor materials typically employ non-covalent interactions to confine the unfused conjugated backbone. This allows the conjugated host structure, linked only by single bonds, to maintain a near-planar conformation even without fusion, thus retaining the high conjugativity characteristic of a conjugated backbone, which is beneficial for light absorption and carrier transport. The main types of non-covalent interactions used in these molecules include hydrogen bonds, O…S, O…H, and F…S interactions.

[0006] Recently, there have been reports on small molecule acceptor materials designed using the conformational locking effect of sterically hindered side chains. These molecules introduce concentrated steric hindrance within adjacent sites, restricting the free rotation of the conjugated backbone and thus improving the conjugation of the backbone structure. At the same time, the steric groups located outside the conjugated matrix plane can also regulate the π-π stacking between the main molecular structures and improve the solubility of the molecules, making an innovation in the structural design of non-fused ring acceptor materials.

[0007] Currently, the core molecular units of this type of receptor material are limited to bi(hetero)aromatic ring systems with sterically hindered side chains, resulting in relatively simple structures. Traditional non-fused triaromatic ring systems typically exhibit torsion angles between the aromatic rings, leading to a non-coplanar overall conformation. Maintaining the coplanarity of non-fused triaromatic ring systems remains a challenge in the field of non-fullerene receptor materials. Summary of the Invention

[0008] This invention aims to overcome the limitations of existing non-fullerene acceptor materials, which suffer from limited structural diversity and difficulty in adjustment. It provides a non-fullerene acceptor material, its preparation method, and its applications. This non-fullerene acceptor material utilizes a non-fused tri(hetero)aromatic ring system as its core building block, ensuring the coplanarity of the tri(hetero)aromatic ring framework. Furthermore, the strong adjustability of the tri(hetero)aromatic ring system enhances the flexibility and diversity of its structural construction, extending the light absorption range to the near-infrared region, thus facilitating the development of novel, highly efficient acceptor materials.

[0009] This invention provides a non-fullerene acceptor material having the structure shown in Formula Ia:

[0010]

[0011] Among them, Ar 1 It is a 6-14 aryl or a 5-12 heteroaryl, wherein the heteroatom in the 5-12 heteroaryl is selected from one or more of N, O and S, and the number of heteroatoms is 1-4;

[0012] Ar 2 It is a 6-14 aryl group, surrounded by one or more R groups. a Substituted 6-14 aryl, 5-12 heteroaryl, or substituted with one or more R b The substituted 5-12 heteroaryl group, wherein the heteroatom is selected from one or more of O, S and Se, and the number of heteroatoms is 1-4; when there are multiple substituents, they may be the same or different.

[0013] A is a 6-14 aryl group, surrounded by one or more R groups. c Substituted 6-14 aryl, 5-12 heteroaryl, or substituted with one or more R d The substituted 5-12-membered heteroaryl group, wherein the heteroatom is selected from one or more of N, O and S, and the number of heteroatoms is 1-4; when there are multiple substituents, they may be the same or different.

[0014] R a R b R c and R d Independently for C1-C 25 alkyl;

[0015] R 1 and R 2 Independently for C1-C 25 alkyl;

[0016] R 1 and R 2 Located in the same ring as Ar 2Adjacent positions;

[0017] R 3 For H, C1-C 25 Alkyl or C1-C 25 Alkoxy;

[0018] m can be 0, 1, 2, 3, or 4;

[0019] In the structure shown in Formula Ia, the *-marked end is connected to an extended conjugate structure, which is used to adjust the band gap and energy level distribution of the acceptor material.

[0020] In one embodiment of the invention, the extended conjugate structure has formulas Ib and Ib. ′ The structure shown, the structure shown in formula Ib and the structure shown in formula Ia, the left side Ar 2 Connected, the formula Ib ′ The structure shown is the same as the right-hand Ar in the structure shown in formula Ia. 2 Connected,

[0021]

[0022] Among them, B 1 and B 2 Independently chemically bonded, 6-14 aryl group, bonded by one or more R e Substituted 6-14 aryl, 5-12 heteroaryl, or substituted with one or more R f The substituted 5-12-membered heteroaryl group, wherein the heteroatom is selected from one or more of N, O and S, and the number of heteroatoms is 1-6; when there are multiple substituents, they may be the same or different.

[0023] C 1 and C 2 Independently

[0024] X represents H, halogen, and C1-C. 25 Alkyl or C1-C 25 Alkoxy;

[0025] R is H or C1-C 25 alkyl;

[0026] R e and R f Independently for C1-C 25 alkyl.

[0027] In this invention or This refers to the corresponding group passing through this or It can be linked to other fragments or groups in the compound.

[0028] In one aspect of the present invention, Ar 1 In the case of a 6-14 aryl group, the 6-14 aryl group is preferably a 6-10 aryl group, such as phenyl or naphthyl.

[0029] In one embodiment of the present invention, A is a 6-14 aryl group, and is substituted by one or more R groups. c In the substituted 6-14 aryl group, the 6-14 aryl group is independently a 6-10 aryl group, preferably phenyl or naphthyl, for example... or

[0030] In one aspect of the present invention, Ar 2 It is a 5-12 membered heteroaryl group, surrounded by one or more R groups. b In the substituted 5-12 heteroaryl group, the 5-12 heteroaryl group is independently a 5-6 member monoheteroaryl or an 8-12 fused heteroaryl. The 5-6 member monoheteroaryl can be independently thiophene. or selenene For example The 8-12 fused aryl groups can independently be dithiophene. benzodithiophene Trithiophene or dithiophenecyclopentadiene

[0031] In one aspect of the present invention, Ar 2 It is a 5-12 membered heteroaryl group, surrounded by one or more R groups. b In the substituted 5-12 heteroaryl group, the heteroatom in the 5-12 heteroaryl group can be independently selected from S or Se. The number of heteroatoms can be 1, 2, or 3.

[0032] In one embodiment of the present invention, A is a 5-12 membered heteroaryl group, surrounded by one or more R groups. d The 5-12 heteroaryl group in the substituted 5-12 heteroaryl group, B 1 and B 2 Independently 5-12 membered heteroaryl, surrounded by one or more R f In the substituted 5-12 heteroaryl group, the 5-12 heteroaryl group is independently a 5-6 member mono-heteroaryl ring or an 8-12 fused heteroaryl ring. The 5-6 member mono-heteroaryl ring can be independently a thiophene group. furanyl Pyrrole, imidazole, pyrazol, oxazol, pyridyl, pyrazinyl, or pyrimidinyl The 8-12 fused aromatic rings may independently be benzothienyl, benzothienyl, benzodithienyl, benzothiadiazolyl, benzodithiadiazolyl, thienothiadiazolyl, thienopyrazinyl, benzotriazolyl, etc. For example

[0033] In one embodiment of the present invention, A is a 5-12 membered heteroaryl group, surrounded by one or more R groups. d The 5-12 heteroaryl group in the substituted 5-12 heteroaryl group, B 1 and B 2 Independently 5-12 membered heteroaryl, surrounded by one or more R f In the substituted 5-12 heteroaryl group, the number of heteroatoms in the 5-12 heteroaryl group can be 1-4, for example, 3.

[0034] In one aspect of the present invention, R 1 and R 2 Independently for C1-C 25 Alkyl, R 3 For C1-C 25 In alkyl groups, the C1-C 25 The alkyl group is independently a C1-C6 alkyl group, more preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl, such as isopropyl.

[0035] In one aspect of the present invention, Ar 1 It is a 6-14 aryl group.

[0036] In one aspect of the present invention, Ar 2 It consists of 5-12 heteroaryl groups.

[0037] In one embodiment of the present invention, A is a 6-14 aryl group or a 5-12 heteroaryl group.

[0038] In one aspect of the present invention, B 1 and B 2 It is independently a chemical bond or a 5-12 membered heteroaryl group.

[0039] In one aspect of the present invention, R 1 and R 2 Independently C1~C 25 alkyl.

[0040] In one aspect of the present invention, R 3 For C1~C 25 alkyl.

[0041] In one embodiment of the present invention, m is 1.

[0042] In one aspect of the present invention, C 1 and C 2 Independently

[0043] In one embodiment of the present invention, X is H.

[0044] In one aspect of the present invention, R 1 R 2 and R 3 same.

[0045] In one aspect of the present invention, B 1 and B 2 same.

[0046] In one aspect of the present invention, C 1 and C 2 same.

[0047] In one embodiment of the present invention, the non-fullerene acceptor material has the following structure.

[0048]

[0049] Among them, Ar 1 Ar 2 A, B 1 B 2 C 1 C 2 R 1 R 2 R 3 The definitions of m and m are as described above.

[0050] In one aspect of the present invention, Ar 1 It is a 6-14 aryl group;

[0051] Ar 2 It consists of 5-12 heteroaryl groups;

[0052] A is a 6-14 aryl group or a 5-12 heteroaryl group;

[0053] B 1 and B 2 Independently formed by chemical bonds or 5-12 membered heteroaryl groups;

[0054] R 1 and R 2 Independently C1~C 25 alkyl;

[0055] R 3 For C1~C 25 alkyl;

[0056] m is 1;

[0057] C 1 and C 2 Independently X is H.

[0058] In one aspect of the present invention, Ar 1 It is a phenyl group.

[0059] In one aspect of the present invention, Ar 2 Independently In one embodiment of the present invention, A is... In one aspect of the present invention, B 1 and B 2 Independent of chemical bonds or In one aspect of the present invention, R 1 and R 2 It is independently isopropyl.

[0060] In one aspect of the present invention, R 3 It is independently isopropyl.

[0061] In one aspect of the present invention, C 1 and C 2 Independently

[0062] In one aspect of the present invention, the structural unit It can be For example For example

[0063] In one embodiment of the present invention, the structure represented by formula Ia can be as follows:

[0064] In one aspect of the present invention, the formula Ib or Ib ′ The structure shown can be independently...

[0065] In one embodiment of the present invention, the non-fullerene acceptor material has any of the following structures:

[0066]

[0067] This invention provides a compound represented by Formula I:

[0068]

[0069] Among them, Ar 1 Ar 2 A, B 1B 2 C 1 C 2 R 1 R 2 R 3 The definitions of m and m are as described above.

[0070] This invention provides a method for preparing the compound represented by Formula I, comprising the following steps: in an organic solvent, in the presence of a base, reacting the compound represented by Formula II with compound C. 1′ and compound C 2′ Perform the reaction shown below.

[0071]

[0072] Among them, C 1′ and C 2′ Independently Ar 1 Ar 2 A, B 1 B 2 C 1 C 2 R 1 R 2 R 3 The definitions of m, X, and R are as described above.

[0073] The operations and conditions in the preparation method described herein can be the conventional operations and conditions in this type of reaction in the art. In this invention, preferably, they are as follows:

[0074] The organic solvent may be a halogenated hydrocarbon solvent, such as chloroform.

[0075] The base may be an organic base, such as pyridine.

[0076] The molar ratio of the base to the compound of formula II can be 20:1 to 100:1, for example 50:1.

[0077] The compound C 1′ Or compound C 2′ The molar ratio with the compound of formula II can be 2:1 to 4:1, for example 3:1.

[0078] The reaction can be carried out at room temperature.

[0079] The progress of the reaction can be detected using conventional monitoring methods in the art (e.g., TLC, HPLC, or NMR), and the reaction endpoint is generally defined as the disappearance or cessation of the reaction of the compound represented by Formula II. The reaction time can be 3–6 hours, for example, 4 hours.

[0080] In one aspect of the present invention, Formula I can be obtained by either Route 1 or Route 2 as follows:

[0081] Route 1,

[0082]

[0083] Route 2,

[0084]

[0085] This invention provides a compound represented by formula II, III, IV or V:

[0086]

[0087] Among them, Ar 1 Ar 2 A, B 1 B 2 R 1 R 2 R 3 The definitions of m and m are as described above.

[0088] In one aspect of the present invention, the compound represented by Formula II is selected from any of the following structures:

[0089]

[0090]

[0091] In one embodiment of the present invention, the compound represented by Formula III may be: In one aspect of the present invention, the compound represented by Formula IV is selected from any of the following structures:

[0092]

[0093]

[0094] In one embodiment of the present invention, the compound represented by formula V may be...

[0095] This invention provides the application of the non-fullerene acceptor material as described above or the compound represented by Formula I as described above as a solar cell material.

[0096] The present invention provides an active layer, wherein the active layer is a blend of a non-fullerene acceptor material as described above or a compound represented by Formula I as described above with a donor polymer PM6; preferably, the compound represented by Formula I is used as the acceptor material.

[0097] The present invention provides an organic solar cell device, wherein the acceptor material of the organic solar cell device is a non-fullerene acceptor material as described above or a compound represented by Formula I as described above.

[0098] In one embodiment of the present invention, the organic solar cell device includes an anode, a hole transport layer, an active layer, an electron transport layer, and a cathode, wherein the active layer is a blend of the compound represented by Formula I and the donor polymer PM6.

[0099] In one embodiment of the present invention, the anode is made of indium tin oxide (ITO); the hole transport layer is made of PEDOT:PSS; the electron transport layer is made of PFN-Br; and the cathode is made of aluminum (Al).

[0100] The preparation method provided by this invention differs from existing methods that introduce sterically hindered side chains. Instead, it modifies Ar with sterically hindered side chains. 2 As an independent building block, it participates in the construction of the conjugated main structure, thereby allowing for the flexible introduction of extended conjugated units in A and B, enriching the designability of the molecular structure, and aiming to obtain high-performance material molecules.

[0101] Terminology Definition

[0102] Unless otherwise specified, the terms used in this invention have the following meanings:

[0103] The term "halogen" refers to fluorine, chlorine, bromine, or iodine.

[0104] The term "alkyl" refers to a straight-chain or branched alkyl group having a specified number of carbon atoms (e.g., C1 to C6). Alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, etc.

[0105] The term "alkoxy" refers to the group R. X -O-, where R X It is an alkyl group as defined above.

[0106] The term "aryl" refers to an aryl group having a specified number of carbon atoms (e.g., C6 to C5). 10 An aryl group is a cyclic group consisting solely of carbon atoms, which may be monocyclic or polycyclic, and at least one ring is aromatic (conforming to Hückel's rule). An aryl group is linked to other segments of the molecule via an aromatic or non-aromatic ring. Aryl groups include, but are not limited to, phenyl and naphthyl groups.

[0107] The term "heteroaryl" refers to a cyclic group having a specified number of ring atoms (e.g., 5 to 10), a specified number of heteroatoms (e.g., 1, 2, or 3), and a specified type of heteroatom (one or more of N, O, and S). It can be monocyclic or polycyclic, and at least one ring is aromatic (conforming to Hückel's rule). Heteroaryl groups are linked to other segments of a molecule via aromatic or non-aromatic rings. Heteroaryl groups include, but are not limited to, furanyl, pyrroleyl, thiopheneyl, pyrazolyl, imidazolyl, oxazolyl, thiazolyl, pyridinyl, pyrimidinyl, and indoleyl groups.

[0108] The term "multiple" refers to 2, 3, 4, or 5.

[0109] When any variable (e.g., group R) a When these terms appear multiple times in the definition of a compound, their definitions are independent and do not affect each other. For example, a compound defined by three R's... a The substituted 6-14 aryl group refers to the 6-14 aryl group being replaced by 3 R groups. a Replace, 3 Rs a The definitions are independent of each other and do not affect each other.

[0110] The positive and progressive effects of this invention are as follows: The non-fullerene acceptor material provided by this invention has a non-fused ring structure, but can maintain the planarity of the triaromatic ring body of the molecular core, which enriches the structural tunability. As a result, organic photovoltaic material molecules can be flexibly constructed using non-fused ring structural units, and the light absorption range can be extended to the near-infrared region, which is conducive to the development of new high-efficiency acceptor materials.

[0111] This invention provides a synthetic strategy for non-fused non-fullerene acceptor molecules modified with sterically hindered side chains, and, guided by this strategy, provides preparation methods and applications for small molecule acceptor materials I-1 to I-5. The designed synthetic strategy ensures full utilization of the introduced side chains for material performance regulation while simplifying the introduction method and enriching structural tunability. This allows for the flexible construction of organic photovoltaic material molecules using non-fused ring structural units, which is beneficial for the development of novel and highly efficient donor-acceptor materials. Attached Figure Description

[0112] Figure 1 Compound 2-1 and UV-Vis absorption spectrum of chloroform solution.

[0113] Figure 2 UV-Vis absorption spectra of chloroform solutions of compounds I-1, I-2, I-3, and I-4.

[0114] Figure 3 UV-Vis absorption spectra of compounds I-1, I-2, I-3 and I-4 in thin film state.

[0115] Figure 4 Current density and voltage curves of organic solar cell devices prepared by compounds I-1, I-2, I-3 and I-4 using PM6 as a donor. Detailed Implementation

[0116] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0117] Example 1: Synthesis of Compound 1:

[0118]

[0119] Step 1: In a three-necked flask, triisopropylbromobenzene (1-1, 14.16 g, 50 mmol), 3-thiopheneboronic acid (1-2, 12.80 g, 100 mmol), potassium phosphate (21.23 g, 100 mmol), tris(benzylacetone)palladium (458 mg, 0.5 mmol), and 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl (821 mg, 2.0 mmol) were added. 100 mL of anhydrous toluene and 100 mL of anhydrous tetrahydrofuran were added as solvents. The mixture was subjected to three cycles of liquid nitrogen freezing-vacuuming-thawing to remove dissolved oxygen from the solvent. The mixture was then heated under reflux for 16 h. The reaction was monitored by TLC using petroleum ether as the developing solvent. Extraction with dichloromethane, washing with saturated sodium chloride solution, drying to anhydrous sodium sulfate, concentration, and separation by column chromatography using petroleum ether as the eluent yielded compounds 1-3, 14.10 g of white solid, with a yield of 98.4%. 1 H NMR(400MHz,Chloroform-d)δ:7.35(dd,J=2.9,4.8Hz,1H),7.04(s,2H),7.01(dd,J=1.2,2.9Hz,1H),6.94(dd,J=1.2,4.8Hz ,1H),2.92(sep,J=6.8Hz,1H),2.66(sep,J=6.8Hz,2H),1.29(d,J=6.8Hz,6H),1.09(d,J=6.8Hz,6H),1.08(d,J=6.8Hz,6H).

[0120] Step 2: Compound 1-3 (13.00 g, 45.4 mmol) was added to a three-necked flask. Ar was purged three times. 50 mL of ultra-dry tetrahydrofuran was added as a solvent. The temperature was lowered to -78 °C. 25.0 mL (2 mol / L) of diisopropylaminolithium solution was slowly added at this low temperature. After the addition was complete, the reaction was stirred at -78 °C for 1 h. Trimethylchlorosilane (6.9 mL, 54.5 mmol) was added dropwise. After the addition was complete, the reaction was carried out at low temperature for 1 h, then moved to room temperature and reacted for another 3 h. The reaction was quenched with saturated ammonium chloride solution, extracted with dichloromethane, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, concentrated, and the crude product was recrystallized from methanol to give compound 1-4, 11.53 g of a white needle-like solid. The yield was 70.7%. 1 H NMR(400MHz,Chloroform-d)δ7.23(d,J=1.1Hz,1H),7.03(s,2H),7.03(d,J=1.1Hz,1H),2.92(sep,J= 6.9Hz, 1H), 2.63 (sep, J=6.9Hz, 2H), 1.28 (d, J=6.9Hz, 6H), 1.08 (dd, J=6.9, 3.9Hz, 12H), 0.31 (s, 9H).

[0121] Step 3: Compounds 1-4 (10.56 g, 29.4 mmol) were added to a three-necked flask. Ar was purged three times. 60 mL of ultra-dry tetrahydrofuran was added as solvent. The temperature was lowered to -78 °C. 14.1 mL of 2.5 mol / L n-butyllithium solution was slowly added at low temperature. After the addition was complete, the reaction was stirred at -78 °C for 1 h. Isopropanol pinacol borate (7.5 mL, 35.3 mmol) was added dropwise. After the addition was complete, the reaction was carried out at low temperature for 1 h, and then moved to room temperature for another 3 h. The reaction was quenched with saturated ammonium chloride solution, extracted with dichloromethane, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, concentrated, and separated by column chromatography with dichloromethane as the eluent. Compound 1 was obtained as a white solid, 10.19 g, with a yield of 71.5%. 1 H NMR(400MHz,Chloroform-d)δ7.09(s,1H),6.97(s,2H),2.92(sep,J=6.9Hz,1H),2.51(sep,J=6.9Hz ,2H),1.29(d,J=6.9Hz,6H),1.10(s,12H),1.06(d,J=6.9Hz,6H),1.02(d,J=6.9Hz,6H),0.32(s,9H).

[0122] Example 2: Synthesis of compounds I-1 to I-4:

[0123]

[0124] (a) Synthesis of compound I-1:

[0125] Step 1: Add 1,4-dibromobenzene (471.8 mg, 2.0 mmol), compound 1 (2.92 g, 6.0 mmol), tetratetraphenylphosphine palladium (92.0 mg, 0.08 mmol), and potassium hydroxide (673.3 mg, 12.0 mmol) to a three-necked flask. Add 40 mL of ethylene glycol dimethyl ether and 10 mL of water as solvents, and perform three cycles of liquid nitrogen freezing-vacuuming-thawing, followed by reflux for 24 h. After the reaction is complete, extract with dichloromethane, wash with saturated sodium chloride solution, dry to anhydrous sodium sulfate, and concentrate. Dissolve the crude product in 15 mL of dichloromethane, and slowly add 15 mL of trifluoroacetic acid while stirring. Stir at room temperature for 5 h. Neutralize the reaction with saturated sodium carbonate solution, extract with dichloromethane, wash with saturated sodium chloride solution, dry to anhydrous sodium sulfate, and concentrate. The crude product was added to 30 mL of methanol and heated to reheat for 10 min. The mixture was filtered while hot, and the solid was collected, washed with methanol, and dried to give compound 2-1, 1.07 g of white solid, with a yield of 82.4%. 1 H NMR(400MHz,Chloroform-d)δ7.23(d,J=5.0Hz,2H),6.96(s,4H),6.91(s,4H),6.83(d,J=5.1Hz,2H),2.89(sep ,J=6.9Hz,2H),2.58(sep,J=6.9Hz,4H),1.27(d,J=6.9Hz,12H),1.01(d,J=6.8Hz,12H),0.80(d,J=6.9Hz,12H).

[0126] Step 2: Compound 2-1 (647 mg, 1.0 mmol), 10 mL of 1,2-dichloroethane, and phosphorus oxychloride (0.95 mL, 10.0 mmol) were added to a three-necked flask. N,N-dimethylformamide (0.8 mL, 10.0 mmol) was added dropwise, and the mixture was heated under reflux for 36 h. After the reaction was complete, 10 mL of saturated sodium carbonate solution was added, and the mixture was stirred for 1 h. The mixture was extracted with dichloromethane, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, concentrated, and separated by column chromatography using petroleum ether:dichloromethane = 1:1 as the eluent. Compound 3-1 was obtained as a yellow solid, 571 mg, with a yield of 81.2%. 1H NMR(400MHz,Chloroform-d)δ9.87(s,2H),7.49(s,2H),7.02(s,4H),6.99(s,4H),2.92(sep,J=6.9Hz ,2H),2.51(sep,J=6.8Hz,4H),1.27(d,J=7.0Hz,12H),1.03(d,J=6.8Hz,12H),0.80(d,J=6.8Hz,12H).

[0127] Step 3: Compound 3-1 (450 mg, 0.64 mmol), 50 mL chloroform, and 3.8 mL pyridine were added to a three-necked flask. 3-(dicyanomethylene)indophenone (497 mg, 2.56 mmol) was added in portions to the reaction flask with stirring at room temperature. The reaction was continued with stirring for 6 h after the addition was complete. The reaction was monitored by TLC using dichloromethane as the developing solvent. After the reaction was complete, the reaction mixture was poured into 200 mL of methanol, and the precipitate was collected by filtration. Excess 3-(dicyanomethylene)indophenone and pyridine were removed by washing with methanol, followed by washing three times each with 15 mL of n-hexane and acetone. The crude product was collected and separated by column chromatography using chloroform as the eluent. Compound I-1 was obtained as a dark green solid, 592.1 mg, with a yield of 87.6%. 1 H NMR(500MHz,Chloroform-d)δ8.85(s,2H),8.72(d,J=7.3Hz,2H),7.96(dd,J=7.0,2.0Hz,2H),7.79(dtd,J=16.2,7.4,1.3Hz,4H),7.66(s,2H),7. 24(s,4H),7.07(s,4H),2.97(sep,J=6.9Hz,2H),2.55(sep,J=6.8Hz,4H),1.33(d,J=7.0Hz,12H),1.08(d,J=6.8Hz,12H),0.87(d,J=6.8Hz,12H).

[0128] (b) Synthesis of compound I-2:

[0129] The synthesis method is the same as that of compound I-1, except that the 1,4-dibromobenzene used in the raw materials is replaced with 2,5-dibromothiophene[3,2-b]thiophene.

[0130] Compound 2-2, a yellow solid, was prepared in 84.9% yield. 1H NMR(400MHz,Chloroform-d)δ7.19(d,J=5.0Hz,2H),7.05(s,4H),6.91(s,2H),6.82(s,2H),2.96(sep,J=6 .9Hz,2H),2.58(sep,J=6.9Hz,4H),1.31(d,J=6.9Hz,12H),1.02(d,J=6.9Hz,12H),0.95(d,J=6.9Hz,12H).

[0131] Compound 3-2 is an orange-yellow solid, prepared in a yield of 67.1%. 1 H NMR(400MHz,Chloroform-d)δ9.85(s,2H),7.46(s,2H),7.20(s,2H),7.10(s,4H),2.98(sep,J=6.9Hz,2H),2.54(sep,J=6.8Hz 4H), 1.33 (d, J=6.9Hz, 12H), 1.04 (d, J=6.8Hz, 12H), 0.97 (d, J=6.8Hz, 12H).

[0132] Compound I-2 is a dark blue solid, prepared in a yield of 70.2%. 1 H NMR(400MHz,Chloroform-d)δ8.79(s,2H),8.72–8.66(m,2H),7.93(dd,J=7.2,1.7Hz,2H),7.83–7.73(m,4H),7.60(s,2H),7.44(s ,2H),7.12(s,4H),3.01(sep,J=6.9Hz,1H),2.53(sep,J=6.8Hz,2H),1.35(d,J=6.9Hz,12H),1.07(s,12H),0.99(d,J=6.8Hz,12H).

[0133] (c) Synthesis of compound I-3:

[0134] The synthesis method is the same as that of compound I-1, except that the 1,4-dibromobenzene used in the raw materials is replaced with 4,7-dibromo-2,1,3-benzothiadiazole.

[0135] Compounds 2-3, orange solids, were prepared in 79.0% yield. 1H NMR(400MHz,Chloroform-d)δ7.53(d,J=5.1Hz,2H),6.93(m,6H),6.69(s,4H),2.87(sep,J=6.8Hz,2 H),2.58(sep,J=6.8Hz,4H),1.26(d,J=6.9Hz,12H),0.99(d,J=6.8Hz,12H),0.64(d,J=6.9Hz,12H).

[0136] Compound 3-3, an orange-red solid, was prepared in 80.1% yield. 1 H NMR(400MHz,Chloroform-d)δ9.95(s,2H),7.55(s,2H),6.97(s,4H),6.85(s,2H),2.89(sep,J=6.9Hz ,2H),2.51(sep,J=6.7Hz,4H),1.28(d,J=6.9Hz,12H),1.02(d,J=6.8Hz,12H),0.66(d,J=6.9Hz,12H).

[0137] Compound I-3 is a dark blue solid, prepared in a yield of 65.2%. 1 H NMR(400MHz,Chloroform-d)δ8.89(s,2H),8.76–8.69(m,2H),8.01(dd,J=6.5,2.5Hz,2H),7.84–7.74(m,6H),6.99(s,4H),6.92( s,2H),2.89(sep,J=6.9Hz,2H),2.52(sep,J=6.8Hz,4H),1.28(d,J=6.9Hz,12H),1.04(d,J=6.8Hz,12H),0.69(d,J=6.8Hz,12H).

[0138] (d) Synthesis of compound I-4:

[0139] Step 1: In a three-necked flask, add 1,4-dibromopyrazine (507 mg, 2.1 mmol), compound 1 (3.10 g, 6.4 mmol), tetratetraphenylphosphine palladium (99.0 mg, 0.08 mmol), and potassium hydroxide (718 mg, 12.8 mmol). Add 42 mL of ethylene glycol dimethyl ether and 10 mL of water as solvents, and perform three cycles of liquid nitrogen freezing-vacuuming-thawing, followed by reflux for 24 h. After the reaction is complete, extract with dichloromethane, wash with saturated sodium chloride solution, dry to anhydrous sodium sulfate, and concentrate. Dissolve the crude product in 15 mL of dichloromethane, and slowly add 15 mL of trifluoroacetic acid while stirring. React at room temperature for 30 h. Neutralize the reaction with saturated sodium carbonate solution, extract with dichloromethane, wash with saturated sodium chloride solution, dry to anhydrous sodium sulfate, and concentrate. The crude product was added to 30 mL of methanol and heated to reheat for 10 min. The mixture was filtered while hot, and the solid was collected, washed with methanol, and dried to give compound 2-4, 1.14 g of white solid, with a yield of 82.6%. 1 H NMR(400MHz,Chloroform-d)δ7.92(s,2H),7.43(d,J=5.0Hz,2H),7.08(s,4H),6.87(d,J=5.0Hz,2H),2.95(sep ,J=7.0Hz,2H),2.60(sep,J=6.8Hz,4H),1.32(d,J=6.9Hz,12H),1.04(d,J=6.8Hz,12H),0.92(d,J=6.9Hz,12H).

[0140] Step 2: Compound 2-4 (650 mg, 1.0 mmol) was added to a three-necked flask, purged with argon three times, and 20 mL of ultra-dry tetrahydrofuran was added as a solvent. The temperature was lowered to -78 °C, and 0.88 mL of 2.5 mol / L n-butyllithium solution was slowly added at low temperature. After the addition was complete, the reaction was continued at -78 °C with stirring for 1 h. N,N-dimethylformamide (0.19 mL, 2.4 mmol) was added dropwise, and the reaction was carried out at low temperature for 1 h after the addition was complete. The reaction was then moved to room temperature and continued for 4 h. The reaction was quenched with saturated ammonium chloride solution, extracted with dichloromethane, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, concentrated, and separated by column chromatography with dichloromethane as the eluent. Compound 3-4 was obtained as a yellow solid, 269 mg, with a yield of 38.2%. 1 H NMR(400MHz,Chloroform-d)δ9.94(s,2H),7.92(s,2H),7.55(s,2H),7.16(s,4H),2.98(sep,J=7.0Hz ,2H),2.56(sep,J=6.8Hz,4H),1.33(d,J=6.9Hz,12H),1.07(d,J=6.9Hz,12H),0.91(d,J=6.8Hz,12H).

[0141] Step 3: Compound 3-4 (135 mg, 0.19 mmol), 20 mL chloroform, and 1.1 mL pyridine were added to a three-necked flask. 3-(dicyanomethylene)indophenone (148 mg, 0.76 mmol) was added in portions to the reaction flask with stirring at room temperature. The reaction was continued with stirring for 6 h after the addition was complete. The reaction was monitored by TLC using dichloromethane as the developing solvent. After the reaction was complete, the reaction mixture was poured into 150 mL of methanol, and the precipitate was collected by filtration. Excess 3-(dicyanomethylene)indophenone and pyridine were removed by washing with methanol, followed by washing three times each with 15 mL of n-hexane and acetone. The crude product was collected and separated by column chromatography using chloroform as the eluent. Compound I-4 was obtained as a dark blue solid, 155.9 mg, with a yield of 77.6%. 1 H NMR(400MHz,Chloroform-d)δ8.81(s,2H),8.71(d,J=7.7Hz,2H),8.07(s,2H),7.96(dd,J=7.0,1.7Hz,2H),7.85–7.74(m,4H),7.67(s,2H ),7.16(s,4H),3.02(sep,J=6.9Hz,2H),2.58(sep,J=6.8Hz,4H),1.38(d,J=7.0Hz,12H),1.10(d,J=6.9Hz,12H),0.95(d,J=6.8Hz,12H).

[0142] Example 3: Synthesis of compound I-5:

[0143]

[0144] Step 1: Compound 2-1 (1.13 g, 1.75 mmol) was added to a three-necked flask, and the flask was purged with argon three times. 20 mL of anhydrous tetrahydrofuran was added, followed by dropwise addition of 1.7 mL of 2.5 mol / L n-butyllithium solution at room temperature. After the addition was complete, the mixture was stirred at room temperature for 1 h. Then, 4.2 mL of 1 mol / L trimethyltin chloride solution was added to the reaction flask, and the mixture was stirred at room temperature for 6 h. The reaction was quenched with water, extracted with dichloromethane, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, and concentrated to obtain a yellow solid. The crude product was recrystallized from methanol / ethyl acetate to give compound 4-1, a pale yellow solid, 1.10 g, with a yield of 64.7%. 1H NMR(400MHz,Chloroform-d)δ6.96(s,4H),6.91(s,2H),2.89(p,J=6.9Hz,2H),2.58(p,J=6.9 Hz,4H),1.27(d,J=6.9Hz,12H),1.01(d,J=6.9Hz,12H),0.80(d,J=6.9Hz,12H),0.06(s,19H).

[0145] Step 2: Compound 4-1 (1.00 g, 1.03 mmol), 4-bromo-7-aldehyde-2,1,3-benzothiadiazole (0.63 g, 2.57 mmol), and tetraphenylphosphine palladium (35.7 mg, 0.03 mmol) were added to a 100 mL three-necked flask. Argon gas was purged three times, and 10 mL of redistilled toluene was added. The reaction was subjected to a three-cycle liquid nitrogen freezing-vacuuming-thawing and refluxing reaction for 24 h. The reaction was monitored by TLC, with dichloromethane as the developing solvent. After the reaction was complete, the mixture was extracted with dichloromethane, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, concentrated, and separated by column chromatography with dichloromethane as the eluent. Compound 4-2 was obtained as a dark red solid, 371 mg, with a yield of 38.2%. 1 HNMR(400MHz,Chloroform-d)δ10.70(s,2H),8.23(d,J=7.5Hz,2H),8.14(s,2H),7.99(d,J=7.6Hz,2H),7.11(s,4H),7.06(s,4H) ,2.94(sep,J=14.3,7.2Hz,2H),2.72(sep,J=6.7Hz,4H),1.32(d,J=6.9Hz,12H),1.09(d,J=6.7Hz,12H),0.87(d,J=6.8Hz,12H).

[0146] Step 3: Compound 4-2 (272 mg, 0.28 mmol), 25 mL chloroform, and 1.7 mL pyridine were added to a three-necked flask. 3-(dicyanomethylene)indophenone (221 mg, 1.14 mmol) was added in portions to the reaction flask with stirring at room temperature. The reaction was continued with stirring for 3 h after the addition was complete. The reaction was monitored by TLC using dichloromethane as the developing solvent. After the reaction was complete, the reaction mixture was poured into 150 mL of methanol, and the precipitate was collected by filtration. Excess 3-(dicyanomethylene)indophenone and pyridine were removed by washing with methanol, followed by washing three times each with 15 mL of n-hexane and acetone. The crude product was collected and separated by column chromatography using chloroform as the eluent. Compound I-5 was obtained as a dark green solid, 279 mg, with a yield of 89.2%. 1H NMR(400MHz,Chloroform-d)δ9.56(s,2H),9.20(s,2H),8.74(d,J=7.8Hz,2H),8.13(s,2H),8.04(s,2H),7.96(d,J=7.2Hz,2H),7.82(dt,J=21.6,7.2Hz, 4H),7.13(s,4H),7.07(s,4H),2.97(sep,J=6.9Hz,2H),2.74(sep,J=6.8Hz, 4H), 1.33 (d, J=6.9Hz, 12H), 1.11 (d, J=6.8Hz, 12H), 0.89 (d, J=6.8Hz, 12H).

[0147] Example 4: Characterization of the planarity of the core triaromatic ring unit in solution

[0148] Compound 2-1 and compound (Number: 2-1*) Configured to 10 -5 The absorption spectrum of a 1 mol / L chloroform solution was measured, and the measured spectra are listed below. Figure 1 This shows that the absorption peak of compound 2-1 is redshifted by 10 nm compared to compound 2-1*, indicating that the three aromatic rings in compound 2-1 remain coplanar even in dilute solutions.

[0149] Example 5: Characterization of absorption spectra of small molecule acceptor materials:

[0150] Small molecule receptor materials I-1, I-2, I-3, and I-4 were dissolved in chloroform to prepare a solution of 10 -5 The UV-Vis spectrum of a mol / L solution was tested, and the measured spectra are listed below. Figure 2 Separately, I-1, I-2, I-3, and I-4 were dissolved in chloroform to prepare a concentration of 10 mg / mL, which was then spin-coated onto a quartz glass plate to obtain a thin film of the acceptor material. The UV-Vis spectrum of the thin film was measured, and the measured spectra are listed below. Figure 3 .

[0151] Example 6

[0152] Using organic small molecule acceptor materials I-1, I-2, I-3, and I-4 and donor polymer PM6 as the active layer of an organic solar cell device, a bulk heterojunction organic solar cell device can be obtained. The device structure is: ITO / PEDOT:PSS / active layer / PFN-Br / Al. Wherein, ITO is an indium tin oxide conductive glass substrate; PEDOT:PSS is a hole transport layer; the active layer is a blend of donor material PM6 and acceptor materials I-1, I-2, I-3, and I-4, with a blending mass ratio of D:A = 1:1.5; PFN-Br is an electron transport layer; and Al is the cathode.

[0153] Fabrication of organic solar cells: ITO glass was ultrasonically cleaned twice in deionized water, acetone, and isopropanol solutions. After drying, the ITO glass was treated with UV-ozone for 30 min. PEDOT:PSS was then spin-coated onto the ITO glass at 4000 rpm for 60 s, followed by annealing at 150℃ for 15 min. The prepared active layer precursor solution was then spin-coated onto the PEDOT:PSS at 4000 rpm for 30 s, followed by thermal annealing at 100℃ for 5 min. A 0.5 mg / mL PFN-Br solution was then spin-coated onto the active layer at 3500 rpm for 30 s. A 100 nm aluminum electrode was then deposited by vapor deposition. The current density-voltage curve (JV) of the device was obtained using a solar simulation system AM 1.5G (100 mW / cm²). 2 The results were obtained from the test.

[0154] The current density versus voltage curves of I-1 based organic solar cell devices are shown below. Figure 4 As shown, the short-circuit current density of the device is 9.23 mA / cm². 2 The open-circuit voltage is 0.95V, the fill factor is 48.75, and the energy conversion efficiency is 4.31%.

[0155] The current density versus voltage curves of organic solar cell devices based on I₂ are shown below. Figure 4 As shown, the short-circuit current density of the device is 4.17 mA / cm². 2 The open-circuit voltage is 0.90V, the fill factor is 43.96, and the energy conversion efficiency is 1.65%.

[0156] The current density versus voltage curves of organic solar cell devices based on I-3 are shown below. Figure 4 As shown, the short-circuit current density of the device is 8.18 mA / cm². 2 The open-circuit voltage is 0.88V, the fill factor is 42.84, and the energy conversion efficiency is 3.78%.

[0157] The current density versus voltage curves of organic solar cell devices based on I-4 are shown below. Figure 4As shown, the short-circuit current density of the device is 8.56 mA / cm². 2 The open-circuit voltage is 0.87V, the fill factor is 54.6, and the energy conversion efficiency is 3.18%.

[0158] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A compound of formula I: ###0001### wherein: A is a 6-14 membered aryl or a 5-12 membered heteroaryl, the 5-12 membered heteroaryl having one or more heteroatoms selected from N, O and S, the number of heteroatoms being 1-6; m is 0, 1 or 2; X is H or halogen. wherein Ar 1 is 6-14 membered aryl; Ar 2 To The compound of formula I satisfies one or more of the following conditions, R 1 and R 2 are independently C1-C 25 alkyl; R 1 and R 2 are each in an adjacent position to the ring Ar 2 ; R 3 is C1-C 25 alkyl; (2) A is a 6-14 membered aryl, the 6-14 membered aryl being independently a 6-10 membered aryl; B 1 and B 2 is independently a chemical bond or a 5-12 membered heteroaryl, wherein the heteroatoms are selected from one or more of N, O and S, and the number of heteroatoms is 1-4; C 1 and C 2 independently are The compound of formula I satisfies one or more of the following conditions, 2. The compound of claim 1 of formula I, wherein (2) A is a 6-14 membered aryl, the 6-14 membered aryl being a phenyl or a naphthyl; (1) Ar 1 In the case of a 6-14 membered aryl group, the 6-14 membered aryl group is a 6-10 membered aryl group. The compound of formula I satisfies one or more of the following conditions, (3) A is a 5-12 membered heteroaryl, B 1 and B 2 independently a 5-12 membered heteroaryl, said 5-12 membered heteroaryl independently is a 5-6 membered single heteroaromatic ring or an 8-12 fused heteroaromatic ring; (4) A is 5-12 membered heteroaryl, B 1 and B 2 independently is 5-12 membered heteroaryl, the number of heteroatoms in said 5-12 membered heteroaryl is 1-4; (5) R 1 and R 2 are independently C1-C 25 alkyl, R 3 is C1-C 25 alkyl, and said C1-C 25 alkyl is independently C1-C6 alkyl.

3. The compound of formula I as described in claim 2, characterized in that, (1) m is 1; (1) Ar 1 is 6-14 membered aryl, said 6-14 membered aryl is phenyl or naphthyl; The compound of formula I satisfies one or more of the following conditions, (3) A is 5-12 membered heteroaryl, B 1 and B 2 independently 5-12 membered heteroaryl, said 5-12 membered heteroaryl is independently thienyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, pyridyl, pyrazinyl, pyrimidinyl, dithiophenyl, benzothiophenyl, benzo dithiophenyl, benzothiadiazolyl, benzo dithiadiazolyl, thienothiadiazolyl, thienopyrazinyl, benzotriazolyl, (4) A is 5-12 membered heteroaryl, B 1 and B 2 independently is 5-12 membered heteroaryl, and the number of heteroatoms in said 5-12 membered heteroaryl is 3; (5) R 1 and R 2 are independently C1-C 25 alkyl, R 3 is C1-C 25 alkyl, and the C1-C 25 alkyl groups are independently methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl or t-butyl.

4. The compound of claim 1 of formula I, wherein The compound of formula I has any one of the following structures: ###0002### ###0003### ###0004### ###0005### ###0006### ###0007### ###0008### ###0009### ###0010### ###0011### ###0012### ###0013### ###0014### ###0015### ###0016### ###0017### ###0018### ###0019### ###0020### ###0021### ###0022### ###0023### ###0024### ###0025### ###0026### ###0027### ###0028### ###0029### ###0030### ###0031### ###0032### ###0033### ###0034### ###0035### ###0036### ###0037### ###0038### ###0039### ###0040### ###0041### ###0042### ###0043### ###0044### ###0045### ###0046### ###0047### ###0048### ###0049### ###0050### ###0051### ###0052### ###0053### ###0054### ###0055### ###0056### ###0057### ###0058### ###0059### ###0060### ###0061### ###0062### ###0063### ###0064### ###0065### ###0066### ###0067### ###0068### ###0069### ###0070### ###0071### ###0072### ###0073### ###0074### ###0075### ###0076### ###0077### ###0078### ###0079### ###0080### ###0081### ###0082### ###0083### ###0084### ###0085### ###0086### ###0087### ###0088### ###0089### ###0090### ###0091### ###0092### ###0093### ###0094### ###0095### ###0096### ###0097### ###0098### ###0099### ###0100### ###0101### ###0102### ###0103### ###0104### ###0105### ###0106### ###0107### ###0108### ###0109### ###0110### ###0111### ###0112### ###0113### ###0114### ###0115### ###0116### ###0117### ###0118### ###0119### ###0120### ###0121### ###0122### ###0123### ###0124### ###0125### ###0126### ###0127### ###0128### ###0129### ###0130### ###0131### ###0132### ###0133### ###0134### ###0135### ###0136### ###0137### ###0138### ###0139### ###0140### ###0141### ###0142### ###0143### ###0144### ###0145### ###0146### ###0147### ###0148### ###0149### ###0150### ###0151### ###0152### ###0153### ###0154### ###0155### ###0156### ###0157### ###0158### ###0159### ###0160### ###0161### ###0162### ###0163### ###0164### ###0165### ###0166### ###0167### ###0168### ###0169### ###0170### ###0171### ###0172### ###0173### ###0174### ###0175### ###0176### ###0177### ###0178### ###0179### ###0180### ###0181### ###0182### ###0183### ###018 ​ (2) R 1 , R 2 , and R 3 are the same; (3) B 1 and B 2 are identical; (4) C 1 and C 2 are identical.

5. The compound of claim 1 of formula I, wherein ​ (1) Ar 1 is phenyl; (2) A is (3) B 1 and B 2 independently a bond or (4) R 1 and R 2 is independently isopropyl; (5) R 3 independently isopropyl; (6) C 1 and C 2 are independently 6. The compound of claim 1 of formula I, wherein Structural unit To 7. The compound of claim 6 of formula I, wherein Structural unit To 8. The compound of claim 7 of formula I, wherein Structural unit To 9. The compound of formula I according to any one of claims 1 to 8, wherein ​ 10. A method for preparing the compound of formula I as described in claim 1, characterized in that, The method for preparing the compound represented by Formula I includes the following steps: in an organic solvent, in the presence of a base, reacting the compound represented by Formula II with compound C. 1′ and compound C 2′ Perform the reaction shown below. wherein C 1′ and C 2′ are independently Ar 1 , Ar 2 , A, B 1 , B 2 , C 1 , C 2 , R 1 , R 2 , R 3 , m and X are as defined in any one of claims 1 to 9. ​ 12. An active layer, characterized by ​ 13. The active layer of claim 12, wherein, ​ 14. An organic solar cell device, characterized by, ​ 15. The organic solar cell device of claim 14, wherein the organic solar cell device is a bulk heterojunction solar cell device. ​ 16. The organic solar cell device of claim 15, wherein the organic solar cell device is a bulk heterojunction solar cell device. ​

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