Polycyclic fusion molecule containing boron-nitrogen coordination bond, preparation method and application of polycyclic fusion molecule in cathode interface layer of organic photovoltaic device
By using multi-cyclic fusion molecules containing boron nitrogen coordination bonds as cathode interface layer material, the interface contact and electron transport of organic solar cells are improved, the problem of existing materials being sensitive to film thickness is solved, performance stability is achieved on a large scale, and large-area preparation and commercial application are promoted.
Patent Information
- Application Number
- CN202510527522.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-25
- Publication Date
- 2025-07-25
AI Technical Summary
The existing organic solar cell cathode interface layer materials are sensitive to film thickness, resulting in a significant reduction in device performance when the thickness exceeds 30 nm, limiting large-area preparation and commercial applications.
Multi-ring fusion molecules containing boron-nitrogen coordination bonds are used as the cathode interface layer material, and the strong dipole moment and n-type semiconductor performance of its asymmetric molecular framework are used to improve interface contact and improve electron transmission capabilities, and adapt to performance stability within a larger film thickness range.
Maintaining good device performance within the film thickness range of 10~100 nm solves the problem of existing materials being sensitive to film thickness, and promotes the large-area preparation and commercial application of organic solar cells.
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Figure CN120365301A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of organic optoelectronic functional materials, and particularly relates to a class of polycyclic fused molecules containing boron-nitrogen coordination bonds, a preparation method thereof, and an application thereof in the cathode interface layer of an organic solar cell. Background Art
[0002] Organic solar cells have been widely studied due to their advantages such as light weight, flexible folding, solution processability, and the advantage of being complementary to silicon and inorganic thin-film solar cells. In recent years, the efficiency of organic solar cells has exceeded 20%, showing the prospect of marketable applications. Organic solar cells adopt a "sandwich" sandwich structure, which respectively includes an anode, an anode interface layer, an organic active layer, a cathode interface layer, and a metal cathode. Among them, the cathode interface layer is a transition layer sandwiched between the organic active layer and the metal cathode, which plays a role in improving the interface contact between the metal and the organic material, reducing interface defects, reducing interface resistance, and improving electron transport and extraction at the interface, thus playing a crucial role in the performance of the entire device. The current cathode interface layer materials mainly use n-type organic conjugated molecules as the backbone, and polar groups are connected to the ends of the alkyl side chains, such as N,N-dimethylamine, nitrogen-oxygen zwitterions, and quaternary ammonium bromide. Among them, the polar groups at the ends of the alkyl side chains can induce an interface dipole between the organic layer and the metal cathode, thereby reducing interface defects; while the n-type conjugated backbone can act as an electron transport medium to improve the transport of interface electrons. However, saturated alkyl side chains are insulators, which hinder the delocalization of electrons between the polar ends and the n-type conjugated backbone. Therefore, this kind of interface layer is very sensitive to the film thickness and usually can only play a better role under the condition of ultra-thin (about 10 nm). Once the thickness of the interface layer exceeds 30 nm, the device performance will be significantly reduced. This kind of cathode interface layer that is very sensitive to the film thickness is not conducive to the large-area preparation and commercial application of organic solar cells. Therefore, developing a new type of cathode interface layer material that is not sensitive to the film thickness is an important link for organic photovoltaic devices to move towards commercialization. Summary of the Invention
[0003] In view of the above problems existing in the art, the present invention provides a class of polycyclic fused molecules containing boron-nitrogen coordination bonds, a preparation method thereof, and an application thereof in the cathode interface layer of an organic solar cell. The present invention can solve the problems of insufficient electron delocalization of existing materials and sensitivity of performance to the film thickness.
[0004] In order to achieve the above object, the technical solution of the present invention is as follows: One object of the present invention is to protect a polycyclic fused molecule containing boron-nitrogen coordination bonds, which has the following structural formula: , In the formula, Ar is any one of the following structural formulas: , wherein, R is a fatty chain, and its structural formula is , p is an integer from 0 to 5, m is an integer from 0 to 20, and n is an integer from 1 to 20; X is any one of the following structural formulas: .
[0005] The second object of the present invention is to protect a preparation method of the polycyclic fused molecule containing a boron-nitrogen coordination bond, and its reaction process is as follows: ; It includes the following steps: 1) Palladium-catalyzed coupling reaction (using any one of steps a and b): Step a: Dissolve the aromatic ring compound substituted with tributyltin (Ar-Sn) and 4,6-dibromopyrimidine in organic solvent A, and use a palladium compound as a catalyst, and cesium fluoride and copper iodide as co-catalysts for the coupling reaction; after the obtained reaction solution is extracted and concentrated, the obtained crude product is separated by column chromatography, and then recrystallized in a mixed solution of dichloromethane and n-hexane to obtain a boronated precursor; Step b: Dissolve the aromatic ring compound substituted with boric acid (Ar-B) and 4,6-dibromopyrimidine in a mixed solvent composed of organic solvent A and an aqueous solution of inorganic base, and use a palladium compound as a catalyst for the coupling reaction; after the obtained reaction solution is extracted and concentrated, the obtained crude product is separated by column chromatography, and then recrystallized in a mixed solution of dichloromethane and n-hexane, and the obtained product is mixed with pyridine hydrochloride (CAS: 628-13-7) for demethylation reaction to obtain a boronated precursor.
[0006] 2) Electrophilic borylation cyclization reaction (using any one of steps c and d): Step c: Dissolve the boronated precursor obtained in step 1) in organic solvent B, and add borylation reagent 1 and an acid-binding agent, stir at room temperature for 12 - 36 h, then add the mixed solution to a diarylzinc solution, and stir at room temperature for 12 - 24 h; after the reaction is completed, the reaction product is extracted and concentrated, and the obtained crude product is separated by column chromatography, and then recrystallized in a mixed solution of dichloromethane and n-hexane or methanol to obtain the polycyclic fused molecule containing a boron-nitrogen coordination bond; Step d: Dissolve the boronated precursor obtained in step 1) in organic solvent B, and add borylation reagent 2, reflux for 12 - 36 h; after the reaction is completed, the reaction product is extracted and concentrated, and the obtained crude product is separated by column chromatography, and then recrystallized in a mixed solution of dichloromethane and n-hexane or methanol to obtain the polycyclic fused molecule containing a boron-nitrogen coordination bond.
[0007] Further, in step a), the tributyltin-substituted aromatic ring compound (Ar-Sn) is any one of the following structural formulas: , wherein R is an aliphatic chain, and its structural formula is , p is an integer from 0 to 5, m is an integer from 0 to 20, and n is an integer from 1 to 20.
[0008] Further, in step a), the molar ratio of the tributyltin-substituted aromatic ring compound Ar-Sn to 4,6-dibromopyrimidine used is 2.3:1 to 4:1.
[0009] Further, in step a), the molar ratio of cesium fluoride to 4,6-dibromopyrimidine used is 1:6 to 1:12.
[0010] Further, in step a), the molar ratio of cuprous iodide to 4,6-dibromopyrimidine used is 1:10 to 1:15.
[0011] Further, in step b), the boric acid-substituted aromatic ring compound (Ar-B) is any one of the following structural formulas: .
[0012] Further, in step b), the molar ratio of the boric acid-substituted aromatic ring compound Ar-B to 4,6-dibromopyrimidine used is 2.3:1 to 4:1.
[0013] Further, in step b), the volume ratio of the organic solvent A to the aqueous solution of inorganic base in the mixed solvent is 5:1 to 3:1.
[0014] Further, in step b), the aqueous solution of inorganic base is an aqueous solution of sodium carbonate, potassium carbonate or cesium carbonate, and its concentration is 1 to 3 M.
[0015] Further, in step b), the molar ratio of the product used to pyridine hydrochloride is 1:10 - 1:50.
[0016] Further, in step b), the temperature of the demethylation reaction is 160 - 200 °C, and the time is 1 - 5 h.
[0017] Further, in steps a) and b), the organic solvent A is any one of chlorobenzene, toluene, N,N-dimethylformamide, tetrahydrofuran, 1,4-dioxane, ethylene glycol dimethyl ether.
[0018] Further, in steps a) and b), the palladium compound is any one of tetrakis(triphenylphosphine)palladium, palladium acetate, bis(dibenzylideneacetone)palladium, bis(tricyclohexylphosphine)palladium dichloride, palladium dichloride.
[0019] Further, in steps a) and b), the molar ratio of the palladium compound used to 4,6-dibromopyrimidine is 3:100 to 1:10; Further, in steps a) and b), the temperature of the coupling reaction is 90 - 130 °C and the time is 12 - 24 h.
[0020] Further, in steps a) and b), the column chromatography separation uses a mixed solution of petroleum ether and dichloromethane with a volume ratio of 10:1 to 1:2 as the eluent.
[0021] Further, in steps a) and b), the volume ratio of dichloromethane to n-hexane in the mixed solution used for recrystallization is 1:2.
[0022] Further, in step c), the boronating reagent 1 is boron trifluoride, boron trichloride or boron tribromide.
[0023] Further, in step c), the acid-binding agent is triethylamine or diisopropylamine.
[0024] Further, the diarylzinc in step c) is prepared by dissolving a zinc salt and a lithium salt in tetrahydrofuran, adding a Grignard reagent, and stirring at room temperature for 0.5 - 2 h.
[0025] Even further, the molar ratio of the zinc salt, lithium salt and Grignard reagent used is 1:1:2.
[0026] Even further, the zinc salt is zinc chloride or zinc bromide.
[0027] Even further, the lithium salt is lithium chloride or lithium bromide.
[0028] Even further, the Grignard reagent is any one of the following structural formulas: 。
[0029] Further, in step c), the molar ratio of the boronating precursor used to the boronating reagent 1 is 1:8 to 1:20.
[0030] Further, in step c), the molar ratio of the boronating precursor used to the acid-binding agent is 1:2 to 1:2.5.
[0031] Further, in step c), the molar ratio of the boronating precursor used to the diarylzinc is 1:10 to 1:30.
[0032] Further, in step d), the boronating reagent 2 is any one of the following structural formulas: 。
[0033] Further, in step d), the molar ratio of the boronization precursor used to the boronization reagent 2 is 1:2.5 to 1:4.
[0034] Further, in steps c) and d), the organic solvent B is any one of dichloromethane, chloroform, toluene, and tetrahydrofuran.
[0035] Further, in steps c) and d), the column chromatography separation uses a mixed solution of petroleum ether and dichloromethane with a volume ratio of 10:1 to 1:2 as the eluent.
[0036] Further, in step f), the volume ratio of dichloromethane to n-hexane or methanol in the mixed solution used for recrystallization is 1:2.
[0037] The third object of the present invention is to protect the application of the polycyclic fused molecule containing a boron-nitrogen coordination bond as a cathode interface layer of an organic solar cell.
[0038] Further, the structure of the organic solar cell is a sandwich-type normal structure, which includes an anode, an anode interface layer, a cathode, an active layer, a cathode interface layer, and a metal cathode.
[0039] Furthermore, the anode is indium tin oxide (ITO); the anode interface layer is PEDOT:PSS; the metal used for the metal cathode is silver; the active layer is a blend composed of a polymer donor PM6 and a small molecule acceptor L8-BO with a mass ratio of 1:1; the cathode interface layer is a polycyclic fused molecule containing a boron-nitrogen coordination bond.
[0040] The beneficial effects of the present invention are as follows: The existing cathode interface layer of organic solar cells usually uses an n-type conjugated backbone, and alkyl side chains are modified on the backbone, with a polar group connected to the end of the side chain. Among them, the n-type conjugated backbone transports electrons, and the polar end induces an interfacial dipole. However, the alkyl side chain belongs to an insulator, which will hinder the delocalization of electrons from the polar end to the conjugated backbone. Therefore, the device performance is very sensitive to the film thickness of the cathode interface layer. Compared with the prior art, the present invention provides an asymmetric molecular backbone containing a boron-nitrogen coordination bond, so that the conjugated backbone itself has a strong dipole moment, which can generate an interfacial dipole at the organic active layer and the cathode interface layer, improving the interfacial contact. At the same time, the conjugated backbone containing a boron-nitrogen coordination bond also belongs to an n-type semiconductor and has good electron transport performance. This way of inducing an interfacial dipole by using the dipole moment of the conjugated backbone can fully ensure the delocalization of electrons, and its performance has a large tolerance for the film thickness of the cathode interface layer, and good device performance can be shown in a large film thickness range (10 - 100 nm). Description of the Drawings
[0041] Figure 11H NMR spectrum of the polycyclic fused molecule 1c containing boron-nitrogen coordination bond prepared in Example 1.
[0042] Figure 2 1H NMR spectrum of the polycyclic fused molecule 2c containing boron-nitrogen coordination bond prepared in Example 2.
[0043] Figure 3 1H NMR spectrum of the polycyclic fused molecule 3c containing boron-nitrogen coordination bond prepared in Example 3.
[0044] Figure 4 1H NMR spectrum of the polycyclic fused molecule 4d containing boron-nitrogen coordination bond prepared in Example 4.
[0045] Figure 5 Device in Example 1 without a cathode interface layer (the active layer was treated with methanol) J-V Curve graph.
[0046] Figure 6 Curve graph of the device prepared with 1c as the cathode interface layer in Example 1 J-V Curve graph.
[0047] Figure 7 Curve graph of the device prepared with 2c as the cathode interface layer in Example 2 J-V Curve graph.
[0048] Figure 8 Curve graph of the device prepared with 3c as the cathode interface layer in Example 3 J-V Curve graph.
[0049] Figure 9 Curve graph of the device prepared with 4d as the cathode interface layer in Example 4 J-V Curve graph. Detailed implementation manners
[0050] A polycyclic fused molecule containing boron-nitrogen coordination bond, the preparation of which comprises the following steps: 1) Palladium-catalyzed coupling reaction (adopting any one of steps a and b): Step a: Dissolve the aromatic ring compound substituted with tributyltin (Ar-Sn) and 4,6-dibromopyrimidine in an organic solvent A at a molar ratio of 2.3:1 to 4:1, add a palladium catalyst and co-catalysts cesium fluoride and copper iodide, and stir and react at 90-130 °C for 12-24 h; after the obtained reaction solution is extracted and concentrated, the obtained crude product is subjected to column chromatography separation using a mixed solution of petroleum ether / dichloromethane (10:1 to 1:2, v / v) as the eluent, and then recrystallized in a mixed solution of dichloromethane / n-hexane (1:2, v / v) to obtain a boronated precursor; Among them, the molar ratio of the palladium catalyst used to 4,6-dibromopyrimidine is 3:100 to 1:10; the molar ratio of cesium fluoride used to 4,6-dibromopyrimidine is 1:6 to 1:12, and the molar ratio of cuprous iodide used to 4,6-dibromopyrimidine is 1:10 to 1:15; Step b: Dissolve the boric acid-substituted aromatic ring compound (Ar-B) and 4,6-dibromopyrimidine in a mixed solvent composed of an organic solvent A and an aqueous solution of an inorganic base (5:1 to 3:1, v / v) at a molar ratio of 2.3:1 to 4:1. Add a palladium catalyst and stir the reaction at 90 to 130 °C for 12 - 24 h; after the obtained reaction solution is extracted and concentrated, the obtained crude product is subjected to column chromatography separation using a mixed solution of petroleum ether / dichloromethane (10:1 to 1:2, v / v) as the eluent, and then recrystallized in a mixed solution of dichloromethane / n-hexane (1:2, v / v). Then mix it with pyridine hydrochloride at a molar ratio of 1:10 - 1:50 and stir the reaction at 160 to 200 °C for 1 - 5 h for demethylation. After that, it is extracted and recrystallized in a mixed solution of dichloromethane / n-hexane (1:2, v / v) to obtain the boronated precursor; Among them, the molar ratio of the palladium catalyst used to 4,6-dibromopyrimidine is 3:100 to 1:10; 2) Electrophilic borylation cyclization reaction (using any one of steps c and d): Step c: Dissolve the boronated precursor obtained in step 1) in an organic solvent B, add a borylation reagent 1 at a molar ratio of 1:8 to 1:20, and add a base scavenger at a molar ratio of 1:2 to 1:2.5. Stir at room temperature for 12 - 36 h, then add the mixed solution to a diarylzinc solution (the molar ratio of the boronated precursor to diarylzinc is 1:10 to 1:30), and stir at room temperature for 12 - 24 h; after the reaction is completed, the reaction product is extracted and concentrated, and the obtained crude product is subjected to column chromatography separation using a mixed solution of petroleum ether and dichloromethane (10:1 to 1:2, v / v) as the eluent, and then recrystallized in a mixed solution of dichloromethane and n-hexane or methanol (1:2, v / v) to obtain the polycyclic fused molecule containing a boron-nitrogen coordination bond; Step d: Dissolve the boronated precursor obtained in step 1) in an organic solvent B, add a borylation reagent 2 at a molar ratio of 1:2.5 to 1:4, and reflux for 12 - 36 h; after the reaction is completed, the reaction product is extracted and concentrated, and the obtained crude product is subjected to column chromatography separation using a mixed solution of petroleum ether and dichloromethane (10:1 to 1:2, v / v) as the eluent, and then recrystallized in a mixed solution of dichloromethane and n-hexane or methanol (1:2, v / v) to obtain the polycyclic fused molecule containing a boron-nitrogen coordination bond.
[0051] Among them, in step 1), the tributyltin-substituted aromatic ring compound (Ar-Sn) is any one of the following structural formulas: , wherein, R is a fatty chain, and its structural formula is , p is an integer from 0 to 5, m is an integer from 0 to 20, and n is an integer from 1 to 20; its preparation method is to dissolve 2-alkylthiophene, 2-alkylselenophene, 2-alkylfuran or 2-alkylthieno[3,2-b]thiophene in tetrahydrofuran under the protection of an inert gas to prepare a solution with a concentration of 10 -2 ~10 mol / L, then add n-butyllithium at a molar ratio of 1:1.2 at -78 °C, stir for 2 hours, then add tributyltin chloride at a molar ratio of 1:1.5, raise the temperature to room temperature and stir for 2 hours. The resulting reaction solution is extracted with a mixture of dichloromethane and water (1:1, v / v). The organic layer is dried, filtered, and rotary evaporated to obtain the product.
[0052] The organic solvent A is any one of chlorobenzene, toluene, N,N-dimethylformamide, tetrahydrofuran, 1,4-dioxane, and ethylene glycol dimethyl ether.
[0053] The palladium catalyst is any one of tetrakis(triphenylphosphine)palladium, palladium acetate, bis(dibenzylideneacetone)palladium, bis(tricyclohexylphosphine)palladium dichloride, and palladium dichloride.
[0054] The boric acid-substituted aromatic ring compound (Ar-B) is any one of the following structural formulas: ; its preparation method is to dissolve 3-methoxythiophene, 3-methoxyselenophene, 3-methoxyfuran or 3-methoxythieno[3,2-b]thiophene in tetrahydrofuran under the protection of an inert gas to prepare a solution with a concentration of 10 -2 ~10 mol / L, then add n-butyllithium at a molar ratio of 1:1.2 at -78 °C, stir for 2 hours, then add trimethyl borate at a molar ratio of 1:1.5, raise the temperature to room temperature and stir for 2 hours. The resulting reaction solution is extracted with a mixture of dichloromethane and water (1:1, v / v). The organic layer is dried, filtered, and rotary evaporated to obtain the product.
[0055] The aqueous solution of inorganic base is an aqueous solution of sodium carbonate, potassium carbonate or cesium carbonate, and its concentration is 1~3 M.
[0056] In step 2), the diarylzinc is prepared by dissolving a zinc salt and a lithium salt in tetrahydrofuran, adding a Grignard reagent, and stirring at room temperature for 0.5 - 2 h; the molar ratio of the zinc salt, the lithium salt to the Grignard reagent is 1:1:2; the zinc salt is zinc chloride or zinc bromide; the lithium salt is lithium chloride or lithium bromide; the Grignard reagent is any one of the following structural formulas: ; Its preparation method is to dissolve 2-bromothiophene, bromobenzene, 2-bromo-5-methoxythiophene, 1-bromo-4-methoxybenzene, 2-bromo-5-(dimethylamino)thiophene or 1-bromo-5-(dimethylamino)benzene in tetrahydrofuran under the protection of inert gas to prepare a 10 -2 ~10 mol / L solution, and then add metallic magnesium in a molar ratio of 1:2 and iodine in a molar ratio of 1:0.001, and stir at room temperature for 2 hours until most of the magnesium is dissolved to obtain the product.
[0057] The borating agent 1 is boron trifluoride, boron trichloride or boron tribromide. The acid-binding agent is triethylamine or diisopropylamine. The organic solvent B is any one of dichloromethane, chloroform, toluene and tetrahydrofuran. The borating agent 2 is any one of the following structural formulas: ; Its preparation method is to dissolve 2-bromothiophene, bromobenzene, 2-bromo-5-methoxythiophene, 1-bromo-4-methoxybenzene, 2-bromo-5-(dimethylamino)thiophene or 1-bromo-5-(dimethylamino)benzene in diethyl ether under the protection of inert gas to prepare a 10 -2 ~10 mol / L solution, then add n-butyllithium in a molar ratio of 1:1 at 0 °C, stir for 1 hour, then add boron trifluoride in a molar ratio of 1:0.3, raise the temperature to room temperature and stir for 12 hours. The obtained product is extracted with a mixed solution of dichloromethane and water (1:1, v / v). The organic layer is dried, filtered and rotary evaporated to obtain a crude product; then the crude product is recrystallized with a mixed solution of dichloromethane and methanol (1:2, v / v) to obtain the product.
[0058] To make the content of the present invention easier to understand, the technical solutions of the present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto.
[0059] Example 1 The synthesis route of a polycyclic fused molecule 1c containing a boron-nitrogen coordination bond provided in this example is as follows:
[0060] 1) Preparation of Compound 1a: Under the protection of an inert gas, 2-octylthiophene (1.96 g, 0.01 mol) was dissolved in tetrahydrofuran (20 mL), and then at -78 °C, 7.5 mL of a 1.6 mol / L n-butyllithium n-hexane solution was added. The mixture was stirred for 2 hours, and then 0.015 mol of tributyltin chloride was added. The temperature was raised to room temperature and stirred for 2 hours. After the reaction was completed, the reaction solution was transferred to a separatory funnel and extracted with water (50 mL) and dichloromethane (50 mL). The organic layer was dried over anhydrous magnesium sulfate, filtered, and concentrated by rotary evaporation to obtain 4.50 g of Compound 1a as a brown oil, with a yield of 92.59%.
[0061] 2) Preparation of Compound 1b: Under an anhydrous and anaerobic environment protected by an inert gas, 4,6-dibromopyrimidine (1 g, 4.20 mmol) was dissolved in 20 mL of N,N-dimethylformamide, and Compound 1a (5.9 g, 12.15 mmol) was added dropwise. Subsequently, tetrakis(triphenylphosphine)palladium (255 mg, 0.22 mmol), copper(I) iodide (69 mg, 0.36 mmol), and cesium fluoride (81 mg, 0.53 mmol) were added. The mixture was heated under reflux at 110 °C for 12 h under a nitrogen atmosphere. After the reaction was completed, it was extracted successively with saturated ammonium chloride solution and dichloromethane. The obtained organic layer was dried over anhydrous magnesium sulfate, filtered, and concentrated by rotary evaporation to obtain a crude product. The crude product was subjected to silica gel column chromatography (200 - 300 mesh) using a mixture of petroleum ether / dichloromethane (20:1, v / v) as the eluent, and the obtained crude product was recrystallized with dichloromethane / n-hexane (1:2, v / v) to obtain 0.98 g of Compound 1b, with a yield of 49.75%.
[0062] 3) Preparation of Compound 1c: Under an anhydrous and anaerobic environment protected by an inert gas, compound 1b (300 mg, 0.64 mmol) was added to a reaction flask containing 20 ml of dichloromethane. Diisopropylamine (129.5 mg, 1.28 mmol) and boron tribromide (1.2825 g, 5.12 mmol) were added at 0 °C, and the mixture was stirred at room temperature for 36 h. Meanwhile, under another anhydrous and anaerobic environment protected by an inert gas, lithium chloride (271.2 mg, 6.4 mmol) and zinc bromide (1.44 g, 6.4 mmol) were added to a reaction tube. The reaction tube was heated with a heat gun under vacuum for two minutes, cooled, and 20 ml of tetrahydrofuran was added. The mixture was stirred at room temperature for 5 minutes, and then a 12.8 ml tetrahydrofuran solution containing 1 M phenylmagnesium bromide (12.8 mmol) was added dropwise. The mixture was stirred at room temperature for 1.5 h, and then the solution from the previous reaction flask was added thereto at 0 °C. The mixture was stirred at room temperature for 12 h. After the reaction was completed, the solvent was removed under reduced pressure, and the mixture was extracted with saturated ammonium chloride solution and dichloromethane. The obtained organic layer was dried over anhydrous magnesium sulfate, filtered, and concentrated by rotary evaporation to obtain a crude product. The crude product was subjected to silica gel column chromatography (200 - 300 mesh) using a mixture of petroleum ether / dichloromethane (10:1, v / v) as the eluent. The obtained crude product was recrystallized with n-hexane and methanol to obtain 102 mg of compound 1c, with a yield of 20.00%.
[0063] The polycyclic fused molecule 1c containing a boron-nitrogen coordination bond was assembled into an organic solar cell. Specifically, ITO was used as the anode, PEDOT:PSS was used as the anode interfacial layer, the commercial polymer PM6 was used as the donor, and the small molecule L8-BO was used as the acceptor. The blend was spin-coated as the active layer. The polycyclic fused molecule 1c containing a boron-nitrogen coordination bond was used as the cathode interfacial layer. Metallic silver was evaporated as the cathode. The device structure was ITO / PEDOT:PSS / PM6:L8-BO / 1c / Ag (the cathode interfacial layer was dissolved in methanol and spin-coated, and the thickness was controlled by the concentration to prepare two thicknesses of 10 nm and 100 nm; meanwhile, for comparison, a device without a cathode interfacial layer was prepared, with the structure ITO / PEDOT:PSS / PM6:L8-BO / Ag, where the surface of the active layer was spin-coated with methanol to offset the influence of the solvent). The devices were tested, and the results are shown in Table 1.
[0064] Table 1
[0065] Example 2 The synthetic route of a polycyclic fused molecule 2c containing a boron-nitrogen coordination bond provided in this example is as follows:
[0066] Preparation of Compound 2c: Under an anhydrous and anaerobic environment protected by an inert gas, compound 1b (300 mg, 0.64 mmol) was added to a reaction flask containing 20 ml of dichloromethane. Diisopropylamine (129.5 mg, 1.28 mmol) and boron tribromide (1.2825 g, 5.12 mmol) were added at 0 °C, and the mixture was stirred at room temperature for 36 h. Meanwhile, under another anhydrous and anaerobic environment protected by an inert gas, lithium chloride (271.2 mg, 6.4 mmol) and zinc bromide (1.44 g, 6.4 mmol) were added to a reaction tube. The reaction tube was heated under vacuum with a heat gun for two minutes, cooled, and then 20 ml of tetrahydrofuran was added. The mixture was stirred at room temperature for 5 minutes, and then a 12.8 ml tetrahydrofuran solution containing 1 M 2-thienylmagnesium bromide (12.8 mmol) was added dropwise. The mixture was stirred at room temperature for 30 minutes, and then the solution from the previous reaction flask was added thereto at 0 °C. The mixture was stirred at room temperature for 12 h. After the reaction was completed, the solvent was removed under reduced pressure, and the mixture was extracted with saturated ammonium chloride solution and dichloromethane. The obtained organic layer was dried over anhydrous magnesium sulfate, filtered, and concentrated by rotary evaporation to obtain a crude product. The crude product was subjected to silica gel column chromatography (200 - 300 mesh) using a mixture of petroleum ether / dichloromethane (10:1, v / v) as the eluent, and the obtained crude product was recrystallized with n-hexane and methanol to obtain 76 mg of compound 2c, with a yield of 14.47 %.
[0067] The polycyclic fused molecule 2c containing a boron-nitrogen coordination bond was assembled into an organic solar cell. Specifically, ITO was used as the anode, PEDOT:PSS was used as the anode interfacial layer, the commercial polymer PM6 was used as the donor, and the small molecule L8-Bo was used as the acceptor. The blend was spin-coated as the active layer. The polycyclic fused molecule 2c containing a boron-nitrogen coordination bond was used as the cathode interfacial layer. Metallic silver was evaporated as the cathode. The device structure was ITO / PEDOT:PSS / PM6:L8-BO / 2c / Ag (the cathode interfacial layer was dissolved in methanol and spin-coated, and the thickness was controlled by the concentration to prepare two thicknesses of 10 nm and 100 nm; meanwhile, for comparison, a device without a cathode interfacial layer was prepared, with the structure ITO / PEDOT:PSS / PM6:L8-BO / Ag, where the surface of the active layer was spin-coated with methanol to offset the influence of the solvent). The devices were tested, and the results are shown in Table 2.
[0068] Table 2
[0069] Example 3 The synthetic route of a polycyclic fused molecule 3c containing a boron-nitrogen coordination bond provided in this example is as follows:
[0070] Preparation of Compound 3c: Under an anhydrous and anaerobic environment protected by inert gas, compound 1b (300 mg, 0.64 mmol) was added to a reaction flask containing 20 ml of dichloromethane. Diisopropylamine (129.5 mg, 1.28 mmol) and boron tribromide (1.2825 g, 5.12 mmol) were added at 0 °C, and the mixture was stirred at room temperature for 36 h. Meanwhile, under another anhydrous and anaerobic environment protected by inert gas, lithium bromide (1.11 g, 12.8 mmol) and zinc bromide (2.88 g, 12.8 mmol) were added to a reaction tube. The reaction tube was heated with a heat gun under vacuum for two minutes, cooled, and then 20 ml of tetrahydrofuran was added. The mixture was stirred at room temperature for 5 minutes, and a solution of 4-methoxyphenylmagnesium bromide (25.6 mmol, 1 M) in tetrahydrofuran (25.6 ml) was added dropwise at 0 °C. The mixture was stirred at room temperature for 30 minutes, and then the solution from the previous reaction flask was added thereto at 0 °C. The mixture was stirred at room temperature for 12 h. After the reaction was completed, the solvent was removed under reduced pressure, and the mixture was extracted with saturated ammonium chloride solution and dichloromethane. The obtained organic layer was dried over anhydrous magnesium sulfate, filtered, and concentrated by rotary evaporation to obtain a crude product. The crude product was subjected to silica gel column chromatography (200 - 300 mesh) using a mixture of petroleum ether / dichloromethane (5:1, v / v) as the eluent, and the obtained crude product was recrystallized from n-hexane and methanol to obtain 35 mg of compound 3c, with a yield of 5.96 %.
[0071] The polycyclic fused molecule 3c containing a boron-nitrogen coordination bond was assembled into an organic solar cell. Specifically, ITO was used as the anode, PEDOT:PSS was used as the anode interfacial layer, the commercial polymer PM6 was used as the donor, and the small molecule L8-BO was used as the acceptor. The blend was spin-coated as the active layer. The polycyclic fused molecule 3c containing a boron-nitrogen coordination bond was used as the cathode interfacial layer. Metallic silver was evaporated as the cathode. The device structure was ITO / PEDOT:PSS / PM6:L8-BO / 3c / Ag (the cathode interfacial layer was dissolved in methanol and spin-coated, and the thickness was controlled by concentration to prepare two thicknesses of 10 nm and 100 nm; meanwhile, for comparison, a device without a cathode interfacial layer was prepared, with the structure ITO / PEDOT:PSS / PM6:L8-BO / Ag, where the surface of the active layer was spin-coated with methanol to offset the influence of the solvent). The devices were tested, and the results are shown in Table 3.
[0072] Table 3
[0073] Example 4 The synthetic route of a polycyclic fused molecule 4d containing a boron-nitrogen coordination bond provided in this example is as follows:
[0074] 1) Preparation of Compound 4b: Under an anhydrous and anaerobic environment protected by an inert gas, 4,6-dibromopyrimidine (500 mg, 2.10 mmol) was dissolved in 20 ml of 1,2-dimethoxyethane. 3-Methoxythiophene-2-boronic acid (Compound 4a, 862.79 mg, 5.46 mmol) was added, followed by an aqueous solution of 2M sodium carbonate (6.31 ml, 12.6 mmol) and tetrakis(triphenylphosphine)palladium (243 mg, 0.21 mmol). The mixture was heated under reflux at 95 °C for 12 h under a nitrogen atmosphere. After the reaction, the mixture was extracted with saturated ammonium chloride solution and dichloromethane. The obtained organic layer was dried over anhydrous magnesium sulfate, filtered, and concentrated by rotary evaporation to obtain a crude product. The crude product was purified by silica gel column chromatography (200 - 300 mesh) using a mixture of petroleum ether / dichloromethane (3:1, v / v) as the eluent. The obtained crude product was recrystallized with a mixture of dichloromethane / n-hexane (1:2, v / v) to obtain 290.90 mg of Compound 4b with a yield of 45.51%.
[0075] 2) Preparation of Compound 4c: Under an anhydrous and anaerobic environment protected by an inert gas, Compound 4b (500 mg, 1.64 mmol) and pyridine hydrochloride (9.4914 g, 82 mmol) were added. The mixture was heated under reflux at 200 °C for 2 h under a nitrogen atmosphere. After the reaction, the mixture was extracted with distilled water and dichloromethane. The obtained organic layer was dried over anhydrous magnesium sulfate, filtered, and concentrated by rotary evaporation to obtain a crude product. The obtained crude product was recrystallized with a mixture of dichloromethane / n-hexane (1:2, v / v) to obtain 411.06 mg of Compound 4c with a yield of 90.56%.
[0076] 3) Preparation of Compound 4d: Under an anhydrous and anaerobic environment protected by an inert gas, Compound 4c (100 mg, 0.36 mmol) was dissolved in 20 ml of toluene, and triphenylborane (219.1 mg, 0.90 mmol) was added. The mixture was heated under reflux at 110 °C for 12 h under a nitrogen atmosphere. After the reaction, the mixture was extracted with distilled water and dichloromethane. The obtained organic layer was dried over anhydrous magnesium sulfate, filtered, and concentrated by rotary evaporation to obtain a crude product. The crude product was purified by silica gel column chromatography (200 - 300 mesh) using a mixture of petroleum ether / dichloromethane (3:1, v / v) as the eluent. The obtained crude product was recrystallized with a mixture of dichloromethane / n-hexane (1:2, v / v) to obtain 65.33 mg of Compound 4d with a yield of 29.87%.
[0077] A polycyclic fused molecule 4d containing a boron-nitrogen coordination bond is assembled into an organic solar cell. Specifically, ITO is used as the anode, PEDOT:PSS is used as the anode interfacial layer, the commercial polymer PM6 is used as the donor, the small molecule L8-BO is used as the acceptor, and co-blending and spin-coating are used as the active layer. A polycyclic fused molecule 1c containing a boron-nitrogen coordination bond is used as the cathode interfacial layer. Evaporated metallic silver is used as the cathode. The device structure is ITO / PEDOT:PSS / PM6:L8-BO / 1c / Ag (the cathode interfacial layer is dissolved in methanol and spin-coated, and the thickness is controlled by the concentration to prepare two thicknesses of 10 nm and 100 nm; at the same time, for comparison, a device without a cathode interfacial layer is prepared, and the structure is ITO / PEDOT:PSS / PM6:L8-BO / Ag, where the surface of the active layer is spin-coated with methanol to offset the influence of the solvent). The devices are tested, and the results are shown in Table 4.
[0078] Table 4
[0079] The above results show that, compared with the device without a cathode interfacial layer, the device using a polycyclic fused molecule containing a boron-nitrogen coordination bond as the interfacial layer has significantly improved performance. At the same time, when the film thickness is increased from 10 nm to 100 nm, the device performance does not show obvious attenuation, proving that using it as the cathode interfacial layer has a high tolerance to the film thickness.
[0080] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.
Claims
1. A polycyclic fused molecule containing a boron-nitrogen coordination bond, characterized in that, It has the following structural formula: ， In the formula, Ar is any one of the following structural formulas: ， Among them, R is a fatty chain, and its structural formula is , p is an integer from 0 to 5, m is an integer from 0 to 20, and n is an integer from 1 to 20; X is any one of the following structural formulas: 。 2. A method for preparing a polycyclic fused molecule containing a boron-nitrogen coordination bond as described in claim 1, characterized in that, It includes the following steps: 1) Palladium-catalyzed coupling reaction: Step a is adopted: The tri-n-butyltin-substituted aromatic ring compound Ar-Sn and 4,6-dibromopyrimidine are co-dissolved in organic solvent A, and a palladium compound is used as a catalyst, and cesium fluoride and copper iodide are used as co-catalysts for the coupling reaction; after the obtained reaction solution is extracted and concentrated, the obtained crude product is separated by column chromatography, and then recrystallized in a mixed solution of dichloromethane and n-hexane to obtain a boronization precursor; Or step b is adopted: The boric acid-substituted aromatic ring compound Ar-B and 4,6-dibromopyrimidine are dissolved in a mixed solvent composed of organic solvent A and an aqueous solution of inorganic base, and a palladium compound is used as a catalyst for the coupling reaction; after the obtained reaction solution is extracted and concentrated, the obtained crude product is separated by column chromatography, and then recrystallized in a mixed solution of dichloromethane and n-hexane, and the obtained product is mixed with pyridine hydrochloride for a demethylation reaction to obtain a boronization precursor; 2) Electrophilic borylation cyclization reaction: Step c is adopted: The boronization precursor obtained in step 1) is dissolved in organic solvent B, and a borylation reagent 1 and an acid-binding agent are added. After stirring at room temperature for 12 - 36 h, the mixed solution is added to a diarylzinc solution, and stirred at room temperature for 12 - 24 h; after the reaction is completed, the reaction product is extracted and concentrated, and the obtained crude product is separated by column chromatography, and then recrystallized in a mixed solution of dichloromethane and n-hexane or methanol to obtain the polycyclic fused molecule containing a boron-nitrogen coordination bond; Or step d is adopted: The boronization precursor obtained in step 1) is dissolved in organic solvent B, and a borylation reagent 2 is added, and refluxed for 12 - 36 h; after the reaction is completed, the reaction product is extracted and concentrated, and the obtained crude product is separated by column chromatography, and then recrystallized in a mixed solution of dichloromethane and n-hexane or methanol to obtain the polycyclic fused molecule containing a boron-nitrogen coordination bond.
3. The preparation method of the polycyclic fused molecule containing a boron-nitrogen coordination bond according to claim 2, wherein In step a), the tri-n-butyltin-substituted aromatic ring compound Ar-Sn is any one of the following structural formulas: ， Among them, R is a fatty chain, and its structural formula is , p is an integer from 0 to 5, m is an integer from 0 to 20, and n is an integer from 1 to 20; The molar ratio of the used tri-n-butyltin-substituted aromatic ring compound Ar-Sn to 4,6-dibromopyrimidine is 2.3:1 - 4:1; the molar ratio of the used cesium fluoride to 4,6-dibromopyrimidine is 1:6 - 1:12; the molar ratio of the used copper iodide to 4,6-dibromopyrimidine is 1:10 - 1:
15.
4. The preparation method of the polycyclic fused molecule containing a boron-nitrogen coordination bond according to claim 2, wherein, In step b), the boric acid-substituted aromatic ring compound Ar-B is any one of the following structural formulas; ； The molar ratio of the used boric acid-substituted aromatic ring compound Ar-B to 4,6-dibromopyrimidine is 2.3:1 - 4:1; the volume ratio of organic solvent A to the aqueous solution of inorganic base in the mixed solvent is 5:1 - 3:1; the aqueous solution of inorganic base is an aqueous solution of sodium carbonate, potassium carbonate or cesium carbonate, and its concentration is 1 - 3 M; the temperature of the demethylation reaction is 160 - 200 °C, the time is 1 - 5 h, and the molar ratio of the used product to pyridine hydrochloride is 1:10 - 1:
50.
5. The preparation method of the polycyclic fused molecule containing a boron-nitrogen coordination bond according to claim 2, wherein, In step 1), the organic solvent A is any one of chlorobenzene, toluene, N,N-dimethylformamide, tetrahydrofuran, 1,4-dioxane, and ethylene glycol dimethyl ether; the palladium compound is any one of tetrakis(triphenylphosphine)palladium, palladium acetate, bis(dibenzylideneacetone)palladium, bis(tricyclohexylphosphine)palladium dichloride, and palladium dichloride; the molar ratio of the palladium compound used to 4,6-dibromopyrimidine is 3:100 to 1:10; the temperature of the coupling reaction is 90 to 130 °C, and the time is 12 - 24 h; the column chromatography separation uses a mixed solution of petroleum ether and dichloromethane with a volume ratio of 10:1 to 1:2 as the eluent; the volume ratio of dichloromethane to n-hexane in the mixed solution used for recrystallization is 1:
2.
6. The preparation method of the polycyclic fused molecule containing boron-nitrogen coordination bond according to claim 2, characterized in that, In step c), the boronating reagent 1 is boron trifluoride, boron trichloride, or boron tribromide; the acid-binding agent is triethylamine or diisopropylamine; the diarylzinc is prepared by dissolving a zinc salt and a lithium salt in tetrahydrofuran, adding a Grignard reagent, and stirring at room temperature for 0.5 - 2 h, and the molar ratio of the zinc salt, lithium salt, and Grignard reagent used is 1:1:2; wherein, the zinc salt is zinc chloride or zinc bromide; the lithium salt is lithium chloride or lithium bromide; the Grignard reagent is any one of the following structural formulas: ； The molar ratio of the boronating precursor used to the boronating reagent 1 is 1:8 to 1:20; the molar ratio of the boronating precursor used to the acid-binding agent is 1:2 to 1:2.5; the molar ratio of the boronating precursor used to the diarylzinc is 1:10 to 1:
30.
7. The preparation method of the polycyclic fused molecule containing a boron-nitrogen coordination bond according to claim 2, characterized in that, In step d), the boronating reagent 2 is any one of the following structural formulas: ; The molar ratio of the boronization precursor used to the boronization reagent 2 is 1:2.5 to 1:
4.
8. The preparation method of the polycyclic fused molecule containing a boron-nitrogen coordination bond according to claim 2, characterized in that, In step 2), the organic solvent B is any one of dichloromethane, chloroform, toluene, and tetrahydrofuran; the column chromatography separation uses a mixed solution of petroleum ether and dichloromethane with a volume ratio of 10:1 to 1:2 as the eluent; the volume ratio of dichloromethane to n-hexane or methanol in the mixed solution used for recrystallization is 1:
2.
9. Use of the polycyclic fused molecule containing a boron-nitrogen coordination bond as described in claim 1 as a cathode interfacial layer in an organic solar cell.
10. The application according to claim 9, characterized in that The structure of the organic solar cell is a sandwich-type normal structure, which includes an anode, an anode interfacial layer, a cathode, an active layer, a cathode interfacial layer, and a metal cathode; wherein the anode is indium tin oxide; the anode interfacial layer is PEDOT:PSS; the metal used for the metal cathode is silver; the active layer is a blend of polymer donor PM6 and small molecule acceptor L8-BO with a mass ratio of 1:1; the cathode interfacial layer is a polycyclic fused molecule containing a boron-nitrogen coordination bond.