Electron acceptor containing sulfur bridging central unit as well as preparation method and application of electron acceptor

Abstract

The invention discloses an electron acceptor containing a sulfur bridging central unit as well as a preparation method and application of the electron acceptor, belongs to the technical field of photoelectric materials, and solves the problems that a non-fullerene acceptor in the prior art cannot have photoelectric properties at the same time and a preparation method of the non-fullerene acceptor is simple. The structural formulas of the electron acceptor containing the sulfur bridging center unit are shown as formulas I-II; in the formula, X1, X2, X3, X4 and X5 are independently selected from any one of a hydrogen atom and a halogen atom; y1 and Y2 are independently selected from any one of a sulfur atom and a selenium atom; r1 and R2 are independently selected from C1-C15 alkyl groups; and R3 and R4 are independently selected from a hydrogen atom and a C1-C15 alkyl group. The organic photoelectric material prepared by the method is simple in steps, easy to purify and definite in structure, and an organic photovoltaic device prepared from the organic photoelectric material has relatively high photoelectric conversion efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic materials, and more specifically to an electron acceptor containing a sulfur-bridging central unit and a preparation method and application thereof. Background Art

[0002] As a clean, renewable green energy technology, organic solar cells have the advantages of low cost, light weight, solution processability and good mechanical flexibility. In the past few years, with the rapid development of organic photoactive layer materials and the continuous improvement of photovoltaic device process level, the power conversion efficiency (PCE) of organic photovoltaic devices has been rapidly improved. At present, a major breakthrough has been achieved, and the PCE has exceeded 20%. Among them, the design of high-performance non-fullerene acceptors (NFAs) is crucial, but also extremely challenging. The non-fullerene acceptors in the active layer are responsible for capturing low-energy photons, which can better match the solar spectrum, but also make the non-fullerene acceptors strictly restricted by the "energy gap law".

[0003] Compared with other types of non-fullerene receptors, high-performance Y-series non-fullerene receptors have formed a more compact and ordered three-dimensional (3D) molecular stacking network. The delocalization of molecular vibrations on adjacent stacked molecules helps non-fullerene receptors break free from the limitations of the "energy gap law", especially for near-infrared (NIR) non-fullerene receptors. Even more exciting is that if the molecular stacking strength and order are further improved through innovative structural exploration, such as considering the irreplaceable role of the central core in determining the molecular stacking pattern and building a three-dimensional network, expanding the central unit to two dimensions is expected to enhance this favorable property.

[0004] However, apart from imide-based moieties (e.g., benzothiadiazole, quinoxaline, or phenazine), few candidate structures have been successfully developed and become the central cores of high-performance non-fullerene receptors. Therefore, it is crucial to construct high-performance non-fullerene receptors that can satisfy specific optoelectronic properties and are easy to synthesize. Summary of the invention

[0005] The present invention provides an electron acceptor containing a sulfur-bridged central unit and a preparation method and application thereof, so as to solve the problem in the prior art that non-fullerene acceptors cannot have both photoelectric properties and a simple preparation method.

[0006] In the first aspect, the present invention provides an electron acceptor containing a sulfur-bridging central unit, the structural formula of which is shown in Formula I to Formula II;

[0007]

[0008] Among them, X 1 , X 2 , X 3 , X 4 , X5 are independently selected from any one of a hydrogen atom and a halogen atom; Y 1 , Y 2 are independently selected from any one of a sulfur atom and a selenium atom; R 1 , R 2 R is independently selected from C1 to C15 alkyl; 3 , R 4 are independently selected from hydrogen atom, C1-C15 alkyl;

[0009] A 1 , A 2 Independently selected from any one of the groups represented by formula A to formula D:

[0010]

[0011] Among them, R 5 , R 6 , R 7 , R 8 They are independently selected from any one of a hydrogen atom and a halogen atom.

[0012] As a possible implementation method, the structural formula of the electron acceptor of the sulfur-containing bridging central unit is shown in Formula (1) to Formula (4);

[0013]

[0014]

[0015] In a second aspect, the present invention provides a method for preparing an electron acceptor of a sulfur-containing bridging central unit according to any possible implementation of the first aspect, comprising the following steps: mixing a dialdehyde compound, a precursor compound of an electron-deficient terminal group, an organic solvent and a catalyst, reacting for 24 hours, extracting, combining the organic phases, drying, removing the solvent, and separating through a column to obtain the electron acceptor of the sulfur-containing bridging central unit; wherein the structural formula of the dialdehyde compound is as shown in Formula III to Formula IV;

[0016]

[0017] Among them, X 1 , X 2 , X 3 , X 4 , X 5 are independently selected from any one of a hydrogen atom and a halogen atom; Y 1 , Y 2 are independently selected from any one of a sulfur atom and a selenium atom; R 1 , R 2 R is independently selected from C1 to C15 alkyl;3 , R 4 They are independently selected from hydrogen atoms and C1-C15 alkyl groups; the precursor compound of the electron-deficient terminal group is selected from any one of the alkanes containing the groups represented by the formulas A to E.

[0018] As a possible implementation manner, the organic solvent is any one of chloroform, dichloromethane and tetrahydrofuran; and / or the catalyst is any one of triethylamine, piperidine, pyridine, ammonium acetate, ammonium propionate and ammonium butyrate.

[0019] As a possible implementation manner, in terms of L / mol, the ratio of the organic solvent to the dialdehyde compound is 10-20:1; and / or the molar ratio of the catalyst to the dialdehyde compound is 1:5.

[0020] As a possible implementation, the preparation method of the dialdehyde compound comprises the following steps: mixing an intermediate donor compound, phosphorus oxychloride, anhydrous N,N-dimethylformamide and a halogenated alkane organic solvent, reacting for 6 to 24 hours, then adding a saturated sodium acetate aqueous solution, reacting at room temperature for 0.5 to 2 hours, extracting, combining the organic phases, drying, removing the solvent, and separating by column to obtain the dialdehyde compound; wherein the structural formula of the intermediate donor compound is shown in Formula V to Formula VI;

[0021]

[0022] Among them, X 1 , X 2 , X 3 , X 4 , X 5 are independently selected from any one of a hydrogen atom and a halogen atom; Y 1 , Y 2 are independently selected from any one of a sulfur atom and a selenium atom; R 1 , R 2 R is independently selected from C1 to C15 alkyl; 3 , R 4 They are independently selected from a hydrogen atom and a C1-C15 alkyl group.

[0023] As a possible implementation manner, the halogenated alkane organic solvent is any one of chloroform, dichloromethane and 1,2-dichloroethane; and / or, in terms of L / mol, the ratio of the halogenated alkane organic solvent to the intermediate donor is 10 to 20:1; and / or, the molar ratio of the intermediate donor, the phosphorus oxychloride and the anhydrous N,N-dimethylformamide is 1:5:10.

[0024] As a possible implementation, the preparation method of the intermediate donor comprises the following steps: subjecting a precursor compound to a ring-closing reaction with triphenylphosphine, and then subjecting the precursor compound to a substitution reaction with 3-(bromomethyl)heptane / 2-butyl-1-bromooctane in a one-pot method to obtain the intermediate donor; wherein the structural formula of the precursor compound is shown in Formula VII to Formula VIII;

[0025]

[0026] Among them, X 1 , X 2 , X 3 , X 4 , X 5 are independently selected from any one of a hydrogen atom and a halogen atom; Y 1 , Y 2 are independently selected from any one of a sulfur atom and a selenium atom; R 3 , R 4 They are independently selected from a hydrogen atom and a C1-C15 alkyl group.

[0027] In a third aspect, the present invention provides an application of an electron acceptor of a sulfur-containing bridging central unit described in any possible implementation of the first aspect or an electron acceptor of a sulfur-containing bridging central unit prepared by the preparation method described in any possible implementation of the second aspect in an organic photoelectric device.

[0028] In a fourth aspect, the present invention provides an organic photoelectric device, using the electron acceptor of the sulfur-containing bridging central unit described in any possible implementation of the first aspect or the electron acceptor of the sulfur-containing bridging central unit prepared by the preparation method described in any possible implementation of the second aspect as its active layer material.

[0029] As a possible implementation, the device is an organic solar cell, a field effect transistor or an organic light emitting diode.

[0030] The organic photoelectric material prepared by the preparation method provided by the present invention has simple steps, is easy to purify, has a certain structure, has good solubility, and is easy to process into a film. Through the moderate chlorination modification of the thianthrene molecules, the molecular stacking mode and the fibrous film morphology are further optimized. The organic photovoltaic device prepared by using the organic photoelectric material in the present invention as an electron acceptor material has excellent photovoltaic performance, and its photoelectric conversion efficiency can reach 19.0%. This innovative work provides a potential path for the development of new non-fullerene acceptors and is expected to promote the device efficiency to break through the bottleneck of 20%. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 This is the UV-visible absorption spectra of the solutions of compounds 1 to 4 provided in the examples of the present invention.

[0033] Figure 2 This is the UV-visible absorption spectra of the thin films of compounds 1 to 4 provided in the embodiments of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In order to solve the problem that the non-fullerene acceptors in the prior art cannot have both photoelectric properties and a simple preparation method, this embodiment provides an electron acceptor containing a sulfur-bridging central unit and a preparation method and application thereof.

[0036] The organic photoelectric material prepared by the preparation method provided by the present invention has simple steps, is easy to purify, has a certain structure, has good solubility, and is easy to process into a film. Through the moderate chlorination modification of the thianthrene molecules, the molecular stacking mode and the fibrous film morphology are further optimized. The organic photovoltaic device prepared by using the organic photoelectric material in the present invention as an electron acceptor material has excellent photovoltaic performance, and its photoelectric conversion efficiency can reach 19.0%. This innovative work provides a potential path for the development of new non-fullerene acceptors and is expected to promote the device efficiency to break through the bottleneck of 20%.

[0037] The technical solution of the present invention will be further described below in conjunction with specific embodiments.

[0038] Example 1

[0039] This embodiment provides the preparation of optoelectronic materials.

[0040] Synthesis route 1:

[0041]

[0042] Synthesis route 2:

[0043]

[0044] In the above-mentioned "Synthesis Route 1" and "Synthesis Route 2", X 1 , X 2 , X 3 , X 4 Both are hydrogen atoms or both are chlorine atoms; X 5 is a fluorine atom; Y 1 , Y 2 At the same time, it is a sulfur atom; R 1 , R 2 At the same time, it is n-undecyl; R 3 , R 4 A is 2-ethylhexyl or 2-butyloctyl; 1 , A 2 At the same time, the following groups:

[0045]

[0046] Among them, R 5 , R 8 At the same time, R 6 , R 7 At the same time it is a fluorine atom.

[0047] 1. Synthesis of the compound of formula (1):

[0048]

[0049] Under nitrogen protection, potassium carbonate (304 mg, 2.2 mmol) was added to a solution of compound 5 (788 mg, 1.00 mmol) in anhydrous N,N-dimethylformamide (DMF, 15.0 ml). After stirring at room temperature for 0.5 hours, catechol (142 mg, 1.00 mmol) was added to the mixture. Stirring was continued at room temperature for 30 minutes, then the reaction was quenched with water and extracted three times with dichloromethane. The organic layer was concentrated under reduced pressure, and the crude product was purified by silica gel column chromatography using dichloromethane and petroleum ether (volume ratio 1: 8) as eluents to obtain compound 6 (721 mg, yield 81%) as a yellow solid.

[0050] 1 H NMR(400MHz,Chloroform-d)δ7.12(d,J=7.2Hz,4H),7.06(dd,J=5.8,3.4Hz,2H),6.95(s, 2H), 2.63(t,J=7.7Hz,4H),1.71–1.62(m,4H),1.29–1.13(m,32H),0.75(t,J=6.6Hz,6H). 13C NMR(101MHz,Chloroform-d)δ143.9,142.8,142.4,138.4,135.1,133.4,131.4,129.1,128 .9,128.2,123.6,123.5,32.1,30.0,29.8,29.8,29.7,29.6,29.6,29.5,28.7,22.8,14.3.

[0051]

[0052] Under nitrogen atmosphere, triphenylphosphine (PPh 3 , 10.26 g, 39.10 mmol). The reaction mixture was heated to reflux and stirred overnight. After cooling to room temperature, the mixture was quickly passed through a silica gel column using dichloromethane as an eluent to obtain a crude cyclized product as a dark red solid. To avoid oxidation, the crude product was not further purified but directly reacted with potassium carbonate (K 2 CO 3 , 696 mg, 5.04 mmol), potassium iodide (KI, 836 mg, 5.04 mmol), 3-(bromomethyl)heptane (1.05 g, 5.04 mmol) and anhydrous N,N-dimethylformamide (DMF, 15.0 ml) were mixed. The mixture was stirred at 100°C for 3 hours. After cooling to room temperature, the reaction was quenched with water and extracted three times with petroleum ether. The organic layer was concentrated under reduced pressure and the crude product was purified by silica gel column chromatography using petroleum ether as eluent to obtain the alkylated product 7 (1.31 g, 64% yield) as a light yellow solid.

[0053] 1 H NMR(400MHz,Chloroform-d)δ7.72(dd,J=5.8,3.3Hz,2H),7.29(dd,J=5.8,3.3Hz,2H),7.01(s,2H),4.56(t,J=7.8Hz,4H ),2.86(t,J=7.7Hz,4H),2.06–1.97(m,2H),1.89(q,J=7.5Hz,4H),1.46–1.29(m,32H),1.11–0.84(m,22H),0.64(m,12H). 13C NMR(101MHz,Chloroform-d)δ142.7,138.5,136.7,136.4,129.5,129.5,129.2,127.6,123.7,121.6,119.9,119.3,118.9,5 4.8,39.6,32.0,29.8,29.8,29.7,29.7,29.6,29.6,29.5,29.5,28.9,27.7,23.1,23.0,22.8,22.8,14.2,13.8,10.1,10.1.

[0054]

[0055] Under argon protection, phosphorus oxychloride (0.6 ml) was added to a solution of compound 7 (546 mg, 0.52 mmol) and N,N-dimethylformamide (DMF, 0.6 ml) in 1,2-dichloroethane (DCE, 30 ml). The resulting mixture was stirred and heated to reflux for 12 hours, then cooled to 0 ° C. The resulting mixture was slowly added to a saturated sodium acetate solution (40 ml) and then stirred at room temperature for 2 hours. The resulting mixture was extracted with dichloromethane, and the organic layer was dried over anhydrous sodium sulfate for 1 hour. After removing the solvent, the crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane (volume ratio 1: 1) as eluent to obtain compound 8 (510 mg, yield 88%) as a yellow solid.

[0056] 1 H NMR(400MHz,Chloroform-d)δ10.14(s,2H),7.71(dd,J=5.8,3.3Hz,2H),7.31(dd,J=5.8,3.3Hz,2H),4.58(dt,J=8.0, 3.8Hz,4H),3.22(t,J=7.7Hz,4H),1.95(t,J=7.5Hz,6H),1.49–1.26(m,32H),1.06–0.85(m,22H),0.66–0.60(m,12H). 13 C NMR(101MHz,Chloroform-d)δ181.8,146.8,143.7,138.1,138.1,137.1,135.7,130.5,130.5,129.6,129.3,128.0,125.0,124.9 ,121.9,120.7,55.0,39.8,32.0,30.5,29.8,29.7,29.7,29.6,29.5,29.4,29.4,28.2,27.6,23.0,22.7,14.2,13.7,10.1,10.1.

[0057]

[0058] Under argon protection, compound 8 (111 mg, 0.1 mmol), dicyanoindanedione (115 mg, 0.5 mmol) and 10 ml of dry chloroform were added to a 100 ml double-necked round-bottom flask. Then 0.2 ml of pyridine was added dropwise to the mixture. The reaction mixture was stirred at 70 ° C for 12 hours. After cooling to room temperature, the reaction mixture was poured into 70 ml of methanol for precipitation. The precipitate was purified by silica gel column chromatography using petroleum ether / chloroform (volume ratio 4:5) as eluent to obtain black target compound 1 (131 mg, yield 86%).

[0059] 1 H NMR(400MHz,Chloroform-d)δ9.17(s,2H),8.58(dd,J=10.0,6.4Hz,2H),7.76–7.68(m,4H),7.36(dd,J=5.8,3.3Hz,2H),4.67(d,J=7.5Hz,4H),3.27(t,J=7 .8Hz,4H),2.05–1.99(m,2H),1.90(t,J=7.2Hz,4H),1.56(m,8H),1.40–1.25( m,30H),1.00–0.85(m,16H),0.74–0.64(m,12H).HR-MS(m / z,MALDI):Calc.for C 88 H 90 F 4 N 6 O 2 S 6 [M + ],1531.5386; found:1531.5429.

[0060] 2. Synthesis of compound of formula (2):

[0061]

[0062] Under nitrogen protection, potassium carbonate (304 mg, 2.2 mmol) was added to a solution of compound 5 (788 mg, 1.00 mmol) in anhydrous N,N-dimethylformamide (DMF, 15.0 ml). After stirring at room temperature for 0.5 hours, 3,6-dichloro-1,2-benzenedithiol (211 mg, 1.00 mmol) was added to the mixture. Stirring was continued at room temperature for 30 minutes, then the reaction was quenched with water and extracted three times with dichloromethane. The organic layer was concentrated under reduced pressure, and the crude product was purified by silica gel column chromatography using dichloromethane and petroleum ether (volume ratio 1: 8) as eluents to obtain compound 9 (720 mg, 75% yield) as a yellow solid.

[0063] 1 H NMR(400MHz,Chloroform-d)δ7.43(s,2H),7.33(s,2H),7.20(s,2H),2.87(t,J =7.6Hz,4H),1.90(t,J=7.4Hz,4H),1.47–1.38(m,30H),0.99(t,J=6.6Hz,8H). 13 C NMR(101MHz,Chloroform-d)δ143.3,143.1,142.7,138.5,135.1,134.4,132.4,131.0,130 .0,128.9,123.8,123.7,32.1,30.0,29.8,29.8,29.7,29.6,29.5,29.5,28.7,22.9,14.3.

[0064]

[0065] Under nitrogen atmosphere, triphenylphosphine (PPh 3 , 10.26 g, 39.10 mmol). The reaction mixture was heated to reflux and stirred overnight. After cooling to room temperature, the mixture was quickly passed through a silica gel column using dichloromethane as an eluent to obtain a crude cyclized product as a dark red solid. To avoid oxidation, the crude product was not further purified but directly reacted with potassium carbonate (K 2 CO 3, 696 mg, 5.04 mmol), potassium iodide (KI, 836 mg, 5.04 mmol), 3-(bromomethyl)heptane (1.05 g, 5.04 mmol) and anhydrous N,N-dimethylformamide (DMF, 15.0 ml) were mixed. The mixture was stirred at 100°C for 3 hours. After cooling to room temperature, the reaction was quenched with water and extracted three times with petroleum ether. The organic layer was concentrated under reduced pressure and the crude product was purified by silica gel column chromatography using petroleum ether as eluent to obtain the alkylated product 10 (1.23 g, 56% yield) as a light yellow solid.

[0066] 1 H NMR(400MHz,Chloroform-d)δ7.22(s,2H),7.01(s,2H),4.64(t,J=8.0Hz,4H),2.89(t,J=7.6Hz ,4H),2.14–2.03(m,2H),1.91(p,J=7.5Hz,4H),1.48–1.31(m,32H),0.98(m,22H),0.70(m,12H). 13 C NMR(101MHz,Chloroform-d)δ143.2,138.8,138.8,137.5,136.8,132.0,129.8,129.8,128.4,123.6,121.7,119.9,119.9,119. 5,117.9,54.9,39.7,32.1,29.9,29.8,29.8,29.7,29.7,29.6,29.5,28.9,27.8,23.1,23.1,22.9,22.9,14.3,13.8,10.1,10.1.

[0067]

[0068] Under argon protection, phosphorus oxychloride (0.6 ml) was added to a solution of compound 10 (582 mg, 0.52 mmol) and N,N-dimethylformamide (DMF, 0.6 ml) in 1,2-dichloroethane (DCE, 30 ml). The resulting mixture was stirred and heated to reflux for 12 hours, then cooled to 0 ° C. The resulting mixture was slowly added to a saturated sodium acetate solution (40 ml) and then stirred at room temperature for 2 hours. The resulting mixture was extracted with dichloromethane, and the organic layer was dried over anhydrous sodium sulfate for 1 hour. After removing the solvent, the crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane (volume ratio 1: 1) as eluent to obtain compound 11 (475 mg, yield 88%) as a yellow solid.

[0069] 1H NMR(400MHz,Chloroform-d)δ10.06(s,2H),7.18(s,2H),4.52(q,J=5.5Hz,4H),3.13 (t,J=7.5Hz,4H),1.88(m,6H),1.36–1.14(m,32H),1.00–0.74(m,22H),0.56(m,12H). 13 C NMR(101MHz,Chloroform-d)δ181.8,146.7,144.0,138.3,138.3,137.3,136.8,132.1,130.7,130.7,129.4,128.7,124.8,124.8,1 21.9,119.6,55.1,39.9,32.0,30.6,29.7,29.7,29.6,29.6,29.6,29.4,29.4,28.1,27.7,23.1,22.8,22.7,14.2,13.7,10.1,10.1.

[0070]

[0071] Under argon protection, compound 11 (118 mg, 0.1 mmol), dicyanoindanedione (115 mg, 0.5 mmol) and 10 ml of dry chloroform were added to a 100 ml double-necked round-bottom flask. Then 0.2 ml of pyridine was added dropwise to the mixture. The reaction mixture was stirred at 70 ° C for 12 hours. After cooling to room temperature, the reaction mixture was poured into 70 ml of methanol for precipitation. The precipitate was purified by silica gel column chromatography using petroleum ether / chloroform (volume ratio 4:5) as eluent to obtain black target compound 2 (136 mg, yield 85%).

[0072] 1 H NMR(400MHz,Chloroform-d)δ9.18(s,2H),8.63–8.54(m,2H),7.72(t,J=7.4Hz,2H),7.40(s,2H),4.70(t,J=7.1Hz,4H),3.28(t,J=7.8H z,4H),2.03(s,2H),1.95–1.86(m,4H),1.55(m,5H),1.41–0.96(m,43H),0.90–0.84(m,6H),0.71(m,12H).HR-MS(m / z,MALDI):Calc.for C 88 H 88 Cl 2 F 4 N 6 O 2 S6 [M + ],1600.4606; found:1600.4617.

[0073] 3. Synthesis of compound of formula (3):

[0074]

[0075] Under nitrogen protection, potassium carbonate (304 mg, 2.2 mmol) was added to a solution of compound 5 (788 mg, 1.00 mmol) in anhydrous N,N-dimethylformamide (DMF, 15.0 ml). After stirring at room temperature for 0.5 hours, 3,4,6-trichloro-1,2-benzenedithiol (245 mg, 1.00 mmol) was added to the mixture. Stirring was continued at room temperature for 30 minutes, then the reaction was quenched with water and extracted three times with dichloromethane. The organic layer was concentrated under reduced pressure, and the crude product was purified by silica gel column chromatography using dichloromethane and petroleum ether (volume ratio 1: 8) as eluents to obtain compound 12 (776 mg, yield 78%) as a yellow solid.

[0076] 1 HNMR(400MHz,Chloroform-d)δ7.50(s,1H),7.39(d,J=3.7Hz,2H),7.15(s,2H),2.8 3(t,J=7.6Hz,4H),1.87(t,J=7.4Hz,4H),1.45–1.33(m,31H),0.96(t,J=6.6Hz,7H). 13 C NMR(101MHz,Chloroform-d)δ143.4,143.4,142.9,142.7,142.6,138.6,136.5,135.1,134.1,132.7,132.2, 130.9,130.8,130.3,129.1,129.0,124.0,123.8,32.1,30.0,29.9,29.9,29.8,29.6,29.6,28.7,22.9,14.3.

[0077]

[0078] Under nitrogen atmosphere, triphenylphosphine (PPh 3, 10.26 g, 39.10 mmol). The reaction mixture was heated to reflux and stirred overnight. After cooling to room temperature, the mixture was quickly passed through a silica gel column using dichloromethane as an eluent to obtain a crude cyclized product as a dark red solid. To avoid oxidation, the crude product was not further purified but directly reacted with potassium carbonate (K 2 CO 3 , 696 mg, 5.04 mmol), potassium iodide (KI, 836 mg, 5.04 mmol), 3-(bromomethyl)heptane (1.05 g, 5.04 mmol) and anhydrous N,N-dimethylformamide (DMF, 15.0 ml) were mixed. The mixture was stirred at 100°C for 3 hours. After cooling to room temperature, the reaction was quenched with water and extracted three times with petroleum ether. The organic layer was concentrated under reduced pressure and the crude product was purified by silica gel column chromatography using petroleum ether as eluent to obtain the alkylated product 13 (1.22 g, 54% yield) as a light yellow solid.

[0079] 1 H NMR(400MHz,Chloroform-d)δ7.30(s,1H),6.84(s,2H),4.45(t,J=8.0Hz,4H),2.70(t,J=7.6Hz,4H ),1.95–1.85(m,2H),1.73(t,J=7.4Hz,4H),1.33–1.14(m,32H),0.99–0.73(m,22H),0.52(m,12H). 13 C NMR(101MHz,Chloroform-d)δ143.2,143.2,139.7,138.9,136.8,136.8,135.9, 132.2,131.7,130.5,129.9,129.8,129.8,128.7,123.6,121.7,121.7,119.8,1 19.8,119.8,119.7,119.6,117.7,117.5,55.0,39.7,32.1,29.9,29.8,29.8,29.7,29.7,29.6,29.5,28.9,27.8,23.1,23.1,22.9,22.8,14.3,13.8,10.1,10.1.

[0080]

[0081] Under argon protection, phosphorus oxychloride (0.6 ml) was added to a solution of compound 13 (600 mg, 0.52 mmol) and N,N-dimethylformamide (DMF, 0.6 ml) in 1,2-dichloroethane (DCE, 30 ml). The resulting mixture was stirred and heated to reflux for 12 hours, then cooled to 0 ° C. The resulting mixture was slowly added to a saturated sodium acetate solution (40 ml) and then stirred at room temperature for 2 hours. The resulting mixture was extracted with dichloromethane, and the organic layer was dried over anhydrous sodium sulfate for 1 hour. After removing the solvent, the crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane (volume ratio 1: 1) as eluent to obtain compound 14 (547 mg, yield 87%) as a yellow solid.

[0082] 1 H NMR(400MHz,Chloroform-d)δ10.14(s,2H),7.48(s,1H),4.68–4.52(m,4H),3.22(t,J =7.7Hz,4H),2.01–1.90(m,6H),1.49–1.23(m,35H),1.06–0.85(m,19H),0.64m,12H). 13 C NMR(101MHz,Chloroform-d)δ181.8,146.8,146.7,144.0,143.9,139.0,138.4,13 8.3,137.3,135.2,132.7,131.8,130.8,130.8,130.7,130.6,129.4,129.0,124.7 ,124.7,124.6,124.6,121.9,121.8,119.5,119.3,55.1,39.8,32.0,30.6,29.8,29.7,29.7,29.6,29.6,29.4,29.4,28.1,27.6,23.0,22.8,22.7,14.2,13.7,10.1.

[0083]

[0084] Under argon protection, compound 14 (121 mg, 0.1 mmol), dicyanoindanedione (115 mg, 0.5 mmol) and 10 ml of dry chloroform were added to a 100 ml double-necked round-bottom flask. Then 0.2 ml of pyridine was added dropwise to the mixture. The reaction mixture was stirred at 70 ° C for 12 hours. After cooling to room temperature, the reaction mixture was poured into 70 ml of methanol and precipitated. The precipitate was purified by silica gel column chromatography using petroleum ether / chloroform (volume ratio 4:5) as eluent to obtain black compound 3 (132 mg, yield 81%).

[0085] 1 H NMR(400MHz,Chloroform-d)δ9.17(d,J=0.6Hz,2H),8.58(dd,J=7.5,4.8Hz,2H),7.71(t,J=5.6Hz,2H),7.59(s,1H),4.70(t,J=5.3Hz,4H),3.27(t,J=5. 9Hz,4H),2.02(m,2H),1.94–1.85(m,4H),1.59–1.51(m,6H),1.41–1.17(m,3 2H),0.99(m,10H),0.86(m,6H),0.70(m,12H).HR-MS(m / z,MALDI):Calc.for C 88 H 87 Cl 3 F 4 N 6 O 2 S 6 [M + ],1635.4187; found:1635.4617.

[0086] 4. Synthesis of compound of formula (4):

[0087]

[0088] Under nitrogen protection, potassium carbonate (304 mg, 2.2 mmol) was added to a solution of compound 5 (788 mg, 1.00 mmol) in anhydrous N,N-dimethylformamide (DMF, 15.0 ml). After stirring at room temperature for 0.5 hours, 3,4-dichlorobenzenethiol (179 mg, 1.00 mmol) was added to the mixture. Stirring was continued at room temperature for 30 minutes, then the reaction was quenched with water and extracted three times with dichloromethane. The organic layer was concentrated under reduced pressure, and the crude product was purified by silica gel column chromatography using dichloromethane and petroleum ether (volume ratio 1: 8) as eluents to obtain compound 15 (436 mg, yield 46%) as a yellow solid.

[0089] 1 H NMR(400MHz,Chloroform-d)δ7.34(s,1H),7.28(d,J=2.1Hz,1H),7.26–7.22(m,1H),7.09(d,J=3.7Hz,2H),7.07(s,1H ),7.03(dd,J=8.4,2.2Hz,1H),2.70(t,J=7.8Hz,4H),1.74(q,J=7.3Hz,4H),1.39–1.24(m,32H),0.88(t,J=6.6Hz,6H).13 C NMR(101MHz,Chloroform-d)δ160.7,158.2,143.0,142.8,142.7,142.4,141.4, 141.4,138.7,138.4,135.0,133.5,133.1,132.8,132.6,132.1,132.1,131.1,1 31.0,130.8,130.6,130.6,130.4,125.9,124.5,124.0,123.7,119.5,119.3,32.0,29.9,29.9,29.8,29.7,29.7,29.7,29.7,29.5,29.5,28.6,28.6,22.8,14.2.

[0090]

[0091] Under nitrogen atmosphere, triphenylphosphine (PPh 3 , 10.26 g, 39.10 mmol). The reaction mixture was heated to reflux and stirred overnight. After cooling to room temperature, the mixture was quickly passed through a silica gel column using dichloromethane as an eluent to obtain a crude cyclized product as a dark red solid. To avoid oxidation, the crude product was not further purified but directly reacted with potassium carbonate (K 2 CO 3 , 696 mg, 5.04 mmol), potassium iodide (KI, 836 mg, 5.04 mmol), 2-butyl-1-bromooctane (1.26 g, 5.04 mmol) and anhydrous N, N-dimethylformamide (DMF, 15.0 ml) were mixed. The mixture was stirred at 100 ° C for 3 hours. After cooling to room temperature, the reaction was quenched with water and extracted three times with petroleum ether. The organic layer was concentrated under reduced pressure to obtain a light yellow solid alkylated crude product. To avoid oxidation, the crude product was not further purified, but phosphorus oxychloride (0.6 ml) was directly added to the alkylated crude product (635 mg, 0.52 mmol) and N, N-dimethylformamide (DMF, 0.6 ml) in 1,2-dichloroethane (DCE, 30 ml) under argon protection. The resulting mixture was stirred and heated to reflux for 12 hours and then cooled to 0 ° C. The resulting mixture was slowly added to a saturated sodium acetate solution (40 ml) and then stirred at room temperature for 2 hours. The resulting mixture was extracted with dichloromethane and the organic layer was dried over anhydrous sodium sulfate for 1 hour. After removing the solvent, the crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane (volume ratio 1:1) as eluent to obtain compound 16 (478 mg, yield 72%) as a yellow solid.

[0092] 1 H NMR(400MHz,Chloroform-d)δ10.14(d,J=11.9Hz,2H),7.25–7.18(m,2H),7.01(d,J=8.6Hz,1H),4.57(dd,J=19.8,7.8Hz,4H ),3.16(dt,J=20.1,7.7Hz,4H),1.95(ddt,J=63.3,17.2,7.3Hz,7H),1.45–1.24(m,36H),1.06–0.85(m,32H),0.66(m,13H). 13 CNMR(101MHz,Chloroform-d)δ182.0,146.8,146.7,144.3,143.6,139.2,138.0,137.5,137.3,133.2,130.7,130.1,129.2,128.6,12 7.8,126.4,125.5,123.0,55.0,38.7,31.9,31.6,30.4,30.2,29.6,29.5,29.4,29.4,28.1,27.9,25.2,22.8,22.5,14.2,14.0,13.7.

[0093]

[0094] Under argon protection, compound 16 (128 mg, 0.1 mmol), dicyanoindanedione (115 mg, 0.5 mmol) and 10 ml of dry chloroform were added to a 100 ml double-necked round-bottom flask. Then 0.2 ml of pyridine was added dropwise to the mixture. The reaction mixture was stirred at 70 ° C for 12 hours. After cooling to room temperature, the reaction mixture was poured into 70 ml of methanol for precipitation. The precipitate was purified by silica gel column chromatography using petroleum ether / chloroform (volume ratio 4:5) as eluent to obtain black target compound 4 (151 mg, yield 89%).

[0095] 1H NMR(400MHz,Methylene Chloride-d2)δ9.14(d,J=13.2Hz,2H),8.56(ddd,J=10.1,6.6,5.1Hz,2H),7.71(td,J=7. 6,5.7Hz,2H),7.31–7.25(m,2H),7.09(dd,J=8.6,2.2Hz,1H),4.73(dd,J=21.7,7.9Hz,4H) ,3.20(dt,J=21.4,7.8Hz,4H),2.11(dd,J=12.7,6.2Hz,2H),1.82(ddd,J=20.9,14.8,7.8H z,4H),1.54(m,8H),1.40–0.80(m,62H),0.73–0.62(m,12H).HR-MS(m / z,MALDI):Calc.for C96H105Cl2F5N6O2S5[M+],1700.6307; found:1700.6195.

[0096] Example 2

[0097] This embodiment provides a test of UV-visible absorption spectrum.

[0098] The organic photoelectric compounds prepared in Example 1 were prepared into 10 -5 mol / L and 10 -2 mol / L chloroform solution, the former is used to measure the UV-visible absorption spectrum in solution state, and the latter solution is spun on a quartz plate at 1200rpm to measure the UV-visible absorption spectrum of the film, the scanning range is 300~1000nm, and the measuring instrument is Jasco V-570UV / VIS / NIR Spectrophotometer. The test method of the compound is consistent.

[0099] The UV-visible absorption spectra of compounds 1 to 4 are as follows: Figure 1 As shown. The solution of the compound has strong absorption in the range of 600-900nm, with the maximum absorption peak located between 700-800nm, while the thin film absorption has obvious red shift and the absorption range is widened, with the maximum absorption peak located between 750-850nm. When it is blended with a wide bandgap donor material with complementary spectrum to prepare photovoltaic devices, a higher photoelectric conversion efficiency can be obtained. It can be seen that the UV-visible absorption of the compound in both solution and thin film state has the characteristics of wide and strong spectrum, which is conducive to the effective absorption of sunlight, thereby obtaining a higher short-circuit current density.

[0100] Example 3

[0101] This embodiment provides the preparation and testing of a solar cell device using an electron acceptor as a raw material.

[0102] Conventional devices based on donor D18: non-fullerene acceptors (NFAs) are prepared using the ITO / 2PACz / D18:NFAs / PNDIT-F3N / Ag structure. The specific steps are as follows:

[0103] First, the glass substrate coated with indium tin oxide (ITO) was placed in detergent aqueous solution, deionized water, acetone and isopropanol in turn, cleaned in an ultrasonic bath for 15 minutes each, and then blown dry with nitrogen. Before use, the cleaned ITO substrate was subjected to UV exposure treatment in a UV ozone box (Jelite Company) for 15 minutes. Next, (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz) was first spin-coated on the ITO substrate at a speed of 3000 rpm for 20 seconds. Then it was dried at 100°C in air for 10 minutes. After that, the substrate was transferred to a glove box filled with nitrogen. After that, D18:NFAs (donor to acceptor ratio of 1:1) was completely dissolved in chloroform (CF) at a donor concentration of 4.0 mg / mL and spin-coated at a speed of 2000 rpm for 30 seconds to coat the 2PACz layer. After the spin coating was completed, the mixed film was annealed at 90°C for 5 minutes. The optimal active layer thickness is about 100 nm. PNDIT-F3N (dissolved in methanol containing 0.5% (volume ratio) glacial acetic acid at a concentration of 1 mg / ml) was then spin-coated on the active layer at a speed of 3000 rpm for 20 seconds. -6 Silver electrodes with a thickness of 150 nanometers were deposited under vacuum conditions of 1000 Pa. The active area of ​​the device was 4 square millimeters. When conducting the current-voltage (JV) test, a mask with an area of ​​3.24 square millimeters was used.

[0104] The relevant photoelectric parameters of the solar cell device prepared using compounds 1 to 4 as electron acceptor materials and D18 as donor material are shown in Table 1.

[0105] Table 1 Solar cell performance

[0106]

[0107] Solar cells prepared using compounds 1 to 4 as electron acceptor materials can achieve higher energy conversion efficiency.

[0108] In summary, the single-layer bulk heterojunction solar cell devices prepared using the compounds of the present application as electron acceptor materials have high photoelectric conversion efficiency, of which the highest photoelectric conversion efficiency can reach 19%. In addition, the compounds of the present invention have precise molecular weight, easy molecular structure control, and convenient purification, and are suitable for preparing high-performance organic solar cells with high open circuit voltage, good stability, flexibility, and large area.

[0109] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0110] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. An electron acceptor containing a sulfur-bridging central unit, characterized in that: Its structural formula is shown in Formula I to Formula II; Wherein, X1, X2, X3, X4, and X5 are independently selected from any one of hydrogen atoms and halogen atoms; Y1 and Y2 are independently selected from any one of sulfur atoms and selenium atoms; R1 and R2 are independently selected from C1-C15 alkyl groups; R3 and R4 are independently selected from hydrogen atoms and C1-C15 alkyl groups; A1 and A2 are independently selected from any one of the groups represented by formula A to formula D: Wherein, R5, R6, R7, and R8 are independently selected from any one of a hydrogen atom and a halogen atom.

2. The electron acceptor of the sulfur-containing bridging central unit according to claim 1, characterized in that: Its structural formula is shown in formula (1) to formula (4); 3. The method for preparing the electron acceptor containing the sulfur-bridging central unit according to any one of claims 1 to 2, characterized in that: The following steps are involved: The dialdehyde compound, the precursor compound of the electron-deficient terminal group, the organic solvent and the catalyst are mixed, reacted for 24 hours, extracted, the organic phases are combined, dried, the solvent is removed, and separated by a column to obtain the electron acceptor of the sulfur-containing bridging central unit; Wherein, the structural formula of the dialdehyde compound is as shown in Formula III to Formula IV; Wherein, X1, X2, X3, X4, and X5 are independently selected from any one of hydrogen atoms and halogen atoms; Y1 and Y2 are independently selected from any one of sulfur atoms and selenium atoms; R1 and R2 are independently selected from C1-C15 alkyl groups; R3 and R4 are independently selected from hydrogen atoms and C1-C15 alkyl groups; The precursor compound of the electron-deficient terminal group is selected from any one of alkanes containing the groups represented by Formula A to Formula E.

4. The preparation method according to claim 3, characterized in that: The organic solvent is any one of chloroform, dichloromethane and tetrahydrofuran; And / or, the catalyst is any one of triethylamine, piperidine, pyridine, ammonium acetate, ammonium propionate and ammonium butyrate.

5. The preparation method according to claim 3, characterized in that: In terms of L / mol, the ratio of the organic solvent to the dialdehyde compound is 10 to 20:1; And / or, the molar ratio of the catalyst to the dialdehyde compound is 1:

5.

6. The preparation method according to any one of claims 3 to 5, characterized in that: The preparation method of the dialdehyde compound comprises the following steps: The intermediate donor compound, phosphorus oxychloride, anhydrous N,N-dimethylformamide and a halogenated alkane organic solvent are mixed and reacted for 6 to 24 hours, and then a saturated sodium acetate aqueous solution is added and reacted for 0.5 to 2 hours at room temperature, and then the organic phases are combined, dried, the solvent is removed, and separated by a column to obtain the dialdehyde compound; Wherein, the structural formula of the intermediate donor compound is as shown in Formula V to Formula VI; Among them, X1, X2, X3, X4, and X5 are independently selected from any one of hydrogen atoms and halogen atoms; Y1 and Y2 are independently selected from any one of sulfur atoms and selenium atoms; R1 and R2 are independently selected from C1~C15 alkyl groups; R3 and R4 are independently selected from hydrogen atoms and C1~C15 alkyl groups.

7. The preparation method according to claim 6, characterized in that: The halogenated alkane organic solvent is any one of chloroform, dichloromethane and 1,2-dichloroethane; and / or, in terms of L / mol, the ratio of the halogenated alkane organic solvent to the intermediate donor is 10 to 20:1; And / or, the molar ratio of the intermediate donor, the phosphorus oxychloride and the anhydrous N,N-dimethylformamide is 1:5:

10.

8. The preparation method according to claim 6, characterized in that: The preparation method of the intermediate donor comprises the following steps: After the precursor compound is subjected to a ring-closing reaction with triphenylphosphine, a substitution reaction is carried out with 3-(bromomethyl)heptane / 2-butyl-1-bromooctane in a one-pot method to obtain the intermediate donor; Wherein, the structural formula of the precursor compound is shown in Formula VII to Formula VIII; Among them, X1, X2, X3, X4, and X5 are independently selected from any one of hydrogen atoms and halogen atoms; Y1 and Y2 are independently selected from any one of sulfur atoms and selenium atoms; R3 and R4 are independently selected from hydrogen atoms and C1-C15 alkyl groups.

9. Use of the electron acceptor of the sulfur-containing bridging central unit according to claims 1 to 2 or the electron acceptor of the sulfur-containing bridging central unit prepared by the preparation method according to any one of claims 3 to 8 in an organic optoelectronic device.

10. An organic optoelectronic device, characterized in that: The electron acceptor of the sulfur-containing bridging central unit according to claims 1 to 2 or the electron acceptor of the sulfur-containing bridging central unit prepared by the preparation method according to any one of claims 3 to 8 is used as the active layer material.

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