Non-fullerene acceptor material, mixture and application thereof

Abstract

The invention relates to the technical field of organic photovoltaic cells, in particular to a non-fullerene acceptor material and a mixture containing the non-fullerene acceptor material, and the molecular structure is optimized by limiting the side chain alkyl chain configuration and electron-withdrawing end selection of the non-fullerene acceptor material. When the non-fullerene acceptor material is applied to a photoactive layer of an organic photovoltaic device, the non-fullerene acceptor material shows excellent photoelectric properties.

Description

Technical Field

[0001] The invention relates to the technical field of organic photovoltaic cells, and in particular to a non-fullerene acceptor material, a mixture and applications thereof. Background Art

[0002] Organic Photovoltaic (OPV) cells have the outstanding advantage of being able to manufacture large-area devices through low-cost solution coating technology, and have attracted widespread attention in the past few decades. Thanks to the development of various new OPV materials, especially non-fullerene acceptors (NFAs) with ADA (acceptor-donor-acceptor) structures, the power conversion efficiency (PCE) of a single OPV cell has exceeded 20%, achieving rapid development.

[0003] In 2015, the team led by Zhan Xiaowei from Peking University designed a new fused NFA based on ITIC configuration, which achieved a photoelectric conversion efficiency of 6.8% with the polymer donor material PTB7-TH, opening a new milestone for organic photovoltaic receptor materials. The characteristic of the fused central unit is that there is no easily twisted CC single bond in its structure, so it can maintain good planarity and rigidity. This structure is conducive to π electron delocalization and intramolecular charge transfer. In 2017, the team led by Hou Jianhui from the Chinese Academy of Sciences further designed the IT-4F structure based on ITIC, and achieved a photoelectric conversion efficiency of 13.1% with the donor material PBDB-T-SF.

[0004] In 2019, Zou Yingping's team at Central South University designed and synthesized a new receptor material Y6 based on Y-type (A-DA'DA), which achieved a photoelectric conversion efficiency of 15.7% when combined with the polymer donor material PM6, leading the development of organic photovoltaic receptor materials into a new stage. Subsequent developments based on Y-type receptor materials have ushered in the structural deformation of a variety of derivatives, such as the development of high-efficiency new receptor materials such as L8-BO, BTP-eC9, N3, and BTP-H2. With the innovation of active layer materials, especially Y-type receptor materials, the device performance of organic solar cells has made continuous breakthroughs and has now reached the stage of industrialization.

[0005] Although existing technologies have already laid a certain foundation for the research of non-fullerene acceptor materials, there are few acceptor materials that can be used for indoor photovoltaics, especially Y-type acceptor materials. In order to further improve OPV indoor photovoltaic technology to meet market applications, new non-fullerene acceptor materials still need to be developed. Summary of the invention

[0006] In response to these existing needs in the art, the present invention provides a novel non-fullerene acceptor material, which can effectively improve the optoelectronic performance of an OPV device containing the acceptor material.

[0007] The first aspect of the present invention provides a non-fullerene acceptor material having a structure as shown in the general formula (I):

[0008]

[0009] in: Selected from structural formula (A-1) or (A-2):

[0010]

[0011] represents the junction site;

[0012] Y is selected from S or Se;

[0013] Each occurrence of Z is independently selected from S or Se;

[0014] Each occurrence of R1 is independently selected from a branched chain alkyl group having 8 to 12 carbon atoms;

[0015] Each occurrence of R2 is independently selected from branched chain alkyl groups having 8 to 20 carbon atoms.

[0016] Furthermore, the non-fullerene acceptor material is selected from the structure shown in the general formula (II-1) or (II-2):

[0017]

[0018] In one embodiment, R2 is selected from a branched alkyl group of 8 to 12 carbon atoms; further, R2 is selected from In one embodiment, each occurrence of R1 is independently selected from Specifically, the non-fullerene acceptor material according to the present invention is selected from the following structures, but is not limited thereto:

[0019]

[0020] The second aspect of the present invention relates to a mixture, wherein the mixture comprises a non-fullerene acceptor material as shown in the general formula (I). In one embodiment, the mixture comprises at least two non-fullerene acceptor materials as shown in the general formula (I).

[0021] In one embodiment, the mixture comprises at least two non-fullerene acceptor materials represented by formula (II-1).

[0022] In one embodiment, the mixture comprises at least two non-fullerene acceptor materials as shown in the general formula (II-2). Specifically, the mixture comprises at least two non-fullerene acceptor materials as shown in any one of the structural formulas (N-1), (N-2), (N-3), (N-4), (N-5), (N-6), (N-7), (N-8), (N-9), (N-10), (N-11), and (N-12).

[0023] In a specific embodiment, according to the mixture of the present invention, the mixture consists of the non-fullerene acceptor material described in formula (I).

[0024] In another embodiment, according to the mixture of the present invention, the mixture comprises at least a first compound and a second compound, the first compound is selected from the non-fullerene acceptor material as described in the general formula (I), and the second compound is selected from the structure as described in the general formula (III):

[0025]

[0026] in:

[0027] Y1 is selected from S or Se;

[0028] Each occurrence of Z1 is independently selected from S or Se;

[0029] Each occurrence of R3 is independently selected from a branched chain alkyl group having 8 to 12 carbon atoms;

[0030] Each occurrence of R4 is independently selected from branched chain alkyl groups having 8 to 20 carbon atoms.

[0031] In one embodiment, the R4 is selected from a branched alkyl group having 8 to 12 carbon atoms.

[0032] Furthermore, the second compound is selected from the structure described by general formula (IV):

[0033]

[0034] In one embodiment, each occurrence of R3 is independently selected from

[0035] Specifically, the second compound according to the present invention is selected from the following structures, but is not limited thereto:

[0036]

[0037] In one embodiment, according to the mixture of the present invention, the first compound is selected from the structure described by general formula (II-1).

[0038] In another embodiment, according to the mixture of the present invention, the first compound is selected from the structure described by general formula (II-2).

[0039] In a specific embodiment, according to the mixture of the present invention, the first compound is selected from compound (N-2) or (N-8); further, the second compound is selected from compound (S-2).

[0040] In one embodiment, according to the mixture of the present invention, the mass ratio of the non-fullerene acceptor material of the general formula (I) to the compound of the general formula (III) is preferably in the range of 0.01:0.99-1:1.

[0041] Furthermore, the mass ratio of the non-fullerene acceptor material of the general formula (I) to the compound of the general formula (III) is selected from 0.1:0.9-0.2:0.8.

[0042] In a specific embodiment, the mixture according to the present invention consists of the non-fullerene acceptor material described in the general formula (I) and the compound described in the general formula (III).

[0043] The third aspect of the present invention relates to an organic photovoltaic cell, which comprises the non-fullerene acceptor material according to the first aspect or the mixture according to the second aspect.

[0044] Furthermore, the organic photovoltaic cell according to the present invention comprises a cathode, an anode and a photoactive layer located between the cathode and the anode, and the photoactive layer acceptor material is selected from the non-fullerene acceptor material as described in the first aspect or the mixture as described in the second aspect.

[0045] In a specific embodiment, the organic photovoltaic cell according to the present invention comprises an anode layer, an anode buffer layer, a photoactive layer, a cathode buffer layer and a cathode layer stacked in sequence from bottom to top; the photoactive layer acceptor material is selected from the non-fullerene acceptor material described in the first aspect or the mixture described in the second aspect.

[0046] The non-fullerene acceptor material of the present invention optimizes the molecular structure by limiting the alkyl chain configuration and the electron-withdrawing end of the compound. Specifically, the branched side chain modification of appropriate length will weaken the molecular stacking, thereby facilitating the migration of charges. The IC end substituted with a single Br can achieve fine-tuning of the energy level, thereby showing efficient charge separation. When it is used as a photoactive layer acceptor material in combination with a suitable polymer donor in an indoor organic photovoltaic device, it shows better photoelectric performance.

[0047] The mixture described in the present invention comprises compounds described by formula (I) and formula (III), wherein the compound described by formula (I) and the compound described by formula (III) have similar structures and high miscibility. When the compound is used as a photoactive layer receptor material in an indoor organic photovoltaic device, the phase separation morphology of the blended film is greatly optimized and the exciton dissociation and charge transfer efficiency are improved, thereby achieving excellent indoor photoelectric conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Schematic diagram of the structure of an organic photovoltaic device in a device embodiment.

[0049] Figure 2 It is a device JV curve diagram of device embodiments 5-6 and device comparative example 3. Specific embodiments

[0050] The present invention will be described below in conjunction with preferred embodiments, but the present invention is not limited to the following embodiments. It should be understood that the attached claims summarize the scope of the present invention. Under the guidance of the concept of the present invention, those skilled in the art should be aware that certain changes made to the various embodiments of the present invention will be covered by the spirit and scope of the claims of the present invention.

[0051] Hereinafter, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such herein.

[0052] In the description of the present invention, it should be understood that the terms "upper", "lower", "between layers", etc., indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which organic electronic devices are conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. These are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0053] The terms "and / or", "or / and", and "and / or" used in this article include any one of two or more related listed items, and also include any and all combinations of related listed items, and the arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in this application, the technical solution undoubtedly includes technical solutions that are all connected by "logical and", and undoubtedly includes technical solutions that are all connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, the technical solution that is all connected by "logical OR"), and also includes any and all combinations of A, B, C, and D, that is, the combination of any two or any three of A, B, C, and D, and also includes the combination of four of A, B, C, and D (that is, the technical solution that is all connected by "logical AND").

[0054] In the present invention, organic photovoltaic device, organic solar cell, OPV and OSC have the same meaning and can be interchangeable.

[0055] In the present invention, photoactive layer and active layer have the same meaning and can be interchanged.

[0056] In the present invention, one or more groups "independently selected from" means that when one or more groups appear simultaneously and in multiple places in a compound, they are all independently selected and may be the same or different.

[0057] In the process of describing the structural elements of the present invention, the words "include" or "comprises" and the like used in the present invention mean that the devices or materials appearing before the word include the devices or materials listed after the word and their equivalents, but do not exclude other devices or materials.

[0058] The present invention further provides a method for synthesizing the non-fullerene acceptor material, which is specifically as follows:

[0059] The synthetic route of structural formula (II-1) is as follows:

[0060]

[0061] The synthetic route of structural formula (II-2) is as follows:

[0062]

[0063] The present invention has no particular limitation on the source of the raw materials used in the above reaction, and commercially available raw materials or preparation methods well known to those skilled in the art can be used. The present invention has no particular limitation on the above reaction, and conventional reactions well known to those skilled in the art can be used.

[0064] Compound Synthesis Examples

[0065] The following examples are provided for better understanding of the disclosure of the present invention and are not intended to limit the present invention in any way. The experimental methods used in the following examples are conventional methods unless otherwise specified, and the materials, reagents, etc. used are prior art and can be obtained from commercial sources unless otherwise specified.

[0066] Synthesis of compound (A-1)

[0067]

[0068] Preparation of compound (A-1-1):

[0069] 2,4-dibromobenzaldehyde (2.6 g, 10.0 mmol), dimethyl itaconate (1.7 g, 11.0 mmol), Pd(OAc)2 (112.3 mg, 0.5 mmol), PPh3 (262.3 mg, 1.0 mmol), NaOAc (2.5 g, 30.0 mmol) and THF (60 mL) were added to a 250 mL three-necked flask, nitrogen was evacuated three times, and the mixture was heated to 110 ° C and reacted overnight. The mixture was cooled to room temperature and quickly rinsed through a silica gel short column with petroleum ether as the eluent. The collected solution was concentrated and recrystallized from toluene to obtain compound (A-1-1) (2.2 g, yield 68.3%). MS: 323.42.

[0070] Preparation of compound (A-1-2):

[0071] Compound (A-1-1) (1.9 g, 6.0 mmol), LiOH (718.5 mg, 30.0 mmol), THF (30 mL) and H2O (10 mL) were placed in a 100 mL round-bottom flask and stirred for 24 hours. After the reaction was completed, the reaction mixture was poured into about 100 mL of 1M HCl, and then extracted with ethyl acetate and saturated brine. The organic phase was dried over Na2SO4, filtered and concentrated to obtain compound (A-1-2) (1.7 g, 95.0%) without further purification. MS: 294.80.

[0072] Preparation of compound (A-1-3):

[0073] Compound (A-1-2) (1.5 g, 5.0 mmol), acetic anhydride (12.5 mL) and THF (50 mL) were added to a reaction flask and heated to reflux for 2 hours. The mixture was cooled to room temperature and THF was removed under reduced pressure. The resulting crude product was cooled to -20°C, at which time solids were precipitated. The solids were quickly filtered to obtain compound (A-1-3) (1.1 g, yield 76.9%). MS: 277.45.

[0074] Preparation of compound (A-1-4):

[0075] Compound (A-1-3) (832 mg, 3.0 mmol), ethyl acetoacetate (1.2 mg, 9.0 mmol), triethylamine (1.66 mL) and acetic anhydride were added to a 100 mL dried round-bottom flask and heated to 40 °C for overnight reaction. The reaction mixture was then poured into 1MCl (30 mL) and heated to 80 °C for overnight reaction. Cooled to room temperature, filtered, the solid was washed with water several times until the mother liquor was clear, and the filter cake was vacuum dried to obtain compound (A-1-4) (0.65 g, 78.5%). MS: 274.92.

[0076] Preparation of compound (A-1):

[0077] In a round-bottom flask, add compound (A-1-4) (550 mg, 2.0 mmol) and malononitrile (158 mg, 2.4 mmol), add acetic acid (1.6 mL), piperidine (0.6 mL) and DMF (10 mL) under nitrogen atmosphere, and stir to react overnight. After the reaction is completed, add 1M HCl solution, stir for two hours, and filter the solid obtained by column chromatography, eluent is dichloromethane, and purified to obtain compound (A-1) (435 mg, yield 67.4%). MS: 322.85.

[0078] Synthesis of compound (A-2)

[0079]

[0080] Add compound A-2-1 (450 mg, 2 mmol) and 8 mL of ethanol to a round-bottom flask, stir, and after dissolving, add malononitrile (158 mg, 2.4 mmol), ventilate three times, add sodium acetate (328 mg, 4 mmol) under nitrogen, stir, and react at room temperature for 3 hours until the reaction is basically complete. Stop the reaction, add 50 ml of 10% dilute hydrochloric acid diluted with ice water to precipitate the product. A large amount of dark black solid is seen. After the crude product is purified by column chromatography, about 418 mg of compound (A-2) is obtained, with a yield of 76.3%. MS: 273.94.

[0081] Synthesis Example 1: Synthesis of Compound (N-1)

[0082]

[0083] Preparation of compound (1-2):

[0084] Compound (1-1) (211 mg, 0.2 mmol) and compound (A-2) (55 mg, 0.2 mmol) were dissolved in 40 mL of chloroform, 0.4 mL of pyridine was added, and the mixture was heated to reflux for 4 h. The reaction mixture was cooled to room temperature, the mixture was poured into methanol and filtered, and the solid was purified by silica gel column chromatography with an eluent of PE:DCM = 1:2 (volume ratio) to obtain compound (1-2) (167 mg, 63.8%). MALDI-TOF-MS: 1310.62.

[0085] Preparation of compound (N-1):

[0086] Compound (1-2) (131 mg, 0.1 mmol) and compound (A-1) (33 mg, 0.1 mmol) were dissolved in 30 mL of chloroform, 0.3 mL of pyridine was added, and the mixture was heated to reflux for 4 h. The reaction mixture was cooled to room temperature, the mixture was poured into methanol and filtered, and the solid was purified by silica gel column chromatography with an eluent of PE:DCM = 1:1 (volume ratio) to obtain compound (N-1) (122 mg, 75.3%). MALDI-TOF-MS: 1615.84.

[0087] Synthesis Example 2: Synthesis of Compound (N-2)

[0088]

[0089] Preparation of compound (2-2):

[0090] Compound (2-1) (234 mg, 0.2 mmol) and compound (A-2) (55 mg, 0.2 mmol) were dissolved in 40 mL of chloroform, 0.4 mL of pyridine was added, and the mixture was heated to reflux for 4 h. The reaction mixture was cooled to room temperature, the mixture was poured into methanol and filtered, and the solid was purified by silica gel column chromatography with an eluent of PE:DCM = 1:2 (volume ratio) to obtain compound (2-2) (187 mg, 65.6%). MALDI-TOF-MS: 1423.15.

[0091] Preparation of compound (N-2):

[0092] Compound (2-2) (143 mg, 0.1 mmol) and compound (A-1) (33 mg, 0.1 mmol) were dissolved in 30 mL of chloroform, 0.3 mL of pyridine was added, and the mixture was heated under reflux for 4 h. The reaction mixture was cooled to room temperature, the mixture was poured into methanol and filtered, and the solid was purified by silica gel column chromatography with the eluent being PE:DCM=1:1 (volume ratio) to obtain compound (N-2) (138 mg, 79.7%). MALDI-TOF-MS: 1728.29.

[0093] Synthesis Example 3: Synthesis of Compound (N-8)

[0094]

[0095] Preparation of compound (N-8):

[0096] Compound (2-1) (117 mg, 0.1 mmol) and compound (A-1) (97 mg, 0.3 mmol) were dissolved in 30 mL of chloroform, 0.3 mL of pyridine was added, and the mixture was heated to reflux for 4 h. The reaction mixture was cooled to room temperature, the mixture was poured into methanol and filtered, and the solid was purified by silica gel column chromatography with the eluent being PE:DCM=1:1 (volume ratio) to obtain compound (N-8) (133 mg, 74.6%). MALDI-TOF-MS: 1778.38.

[0097] Synthesis Example 4: Synthesis of Compound (N-10)

[0098]

[0099] Preparation of compound (4-2):

[0100] The compound tributyl(6-(2-butyloctyl)thieno[3,2-b]thiophen-2-yl)stannane (2.6 g, 4.4 mmol), compound (4-1) (862 mg, 2.0 mmol) and Pd(PPh3)Cl2 (70.2 mg, 0.1 mmol) were dissolved in 100 mL of dry toluene and stirred at 80°C overnight. After cooling to room temperature, the reaction was extracted with dichloromethane and saturated brine, and the organic phase was dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography with the eluent being PE:DCM=3:1 (volume ratio) to obtain compound (4-2) (1.3 g, 75.9%). MS: 886.78.

[0101] Preparation of compound (4-3):

[0102] Compound (4-2) (0.89 g, 1.0 mmol) and triethyl phosphate (5 mL) were dissolved in o-dichlorobenzene (10 mL), nitrogen was evacuated three times, and the mixture was heated to 180 °C and reacted overnight. After cooling to room temperature, the mixture was extracted with dichloromethane and saturated brine, and the organic phase was dried over anhydrous Na2SO4 and concentrated under reduced pressure to obtain a crude product. Without purification, the crude product was added to a reaction bottle, 2-butyl-1-bromooctane (373.8 mg, 1.5 mmol), potassium hydroxide (196.4 mg, 3.5 mmol) and DMF (10 mL) were added, nitrogen was evacuated three times, and the mixture was heated to 110 °C and reacted for 12 h. A large amount of water and ethyl acetate were added to extract and remove DMF, and the organic phase was dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography with the eluent being PE:DCM=6:1 (volume ratio) to obtain compound (4-3) (535 mg, 46.2%). MALDI-TOF-MS:1158.73.

[0103] Preparation of compound (4-4):

[0104] Under nitrogen atmosphere, compound (4-3) (232 mg, 0.2 mmol) was dissolved in anhydrous POCl3 (613.3 mg, 4.0 mmol), and DMF (73.1 mg, 1.0 mmol) was added. The reaction was heated to 90°C and stirred overnight. After the reaction was completed, it was cooled to room temperature, and the reaction solution was slowly added to ice water and extracted with ethyl acetate. The organic phase was dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography with an eluent of PE:DCM = 1:2 (volume ratio) to obtain solid compound (4-4) (147 mg, 60.4%). MALDI-TOF-MS: 1214.67.

[0105] Preparation of compound (N-10):

[0106] Compound (4-4) (122 mg, 0.1 mmol) and compound (A-1) (97 mg, 0.3 mmol) were dissolved in 30 mL of chloroform, 0.3 mL of pyridine was added, and the mixture was heated to reflux for 4 h. The reaction mixture was cooled to room temperature, the mixture was poured into methanol and filtered, and the solid was purified by silica gel column chromatography with the eluent being PE:DCM=1:1 (volume ratio) to obtain compound (N-10) (137 mg, 75.1%). MALDI-TOF-MS: 1825.29.

[0107] Organic Photovoltaic Device Preparation Example

[0108] The following is a detailed description of the preparation process of the OPV device including the above compounds through specific examples. The OPV device structure is as follows: indium tin oxide ITO / ZnO / photoactive layer / MoO3 / Ag

[0109] The preparation steps of device embodiment 1 are as follows:

[0110] 1) ITO substrate cleaning:

[0111] The ITO conductive glass was cleaned with detergent, rinsed, and then ultrasonically cleaned with deionized water, acetone, and isopropanol for 15 minutes, then blown dry with nitrogen and treated in a plasma cleaner for 5 minutes to further clean the surface and improve wettability.

[0112] 2) Preparation of cathode buffer layer

[0113] In air, ZnO precursor solution (100 mg of zinc acetate was dissolved in 1.0 mL of 2-methoxyethanol, and then 28 μL of ethanolamine was added to prepare a precursor solution) was evenly spin-coated on ITO at a spin speed of 4000 rpm for 30 s, and dried at 220° C. for 30 min to obtain a cathode buffer layer.

[0114] 3) Preparation of photoactive layer

[0115] In a glove box (inert gas atmosphere), the photoactive layer material solution is evenly spin-coated on the cathode buffer layer at a rotation speed of 1800-4000 rpm to obtain an active material layer with a total thickness of about 100 nm; wherein the donor material in the photoactive layer material solution is selected from polymer D18; the acceptor material is selected from compound (N-1); polymer D18: compound (N-1) are added to a chloroform solution at a mass ratio of 1:1.2, and the total concentration is 10 mg / mL.

[0116] 4) Anode buffer layer preparation

[0117] In high vacuum (1×10 -6 MoO3 was evaporated onto the photoactive layer at 400 mbar to obtain an anode buffer layer with a thickness of about 10 nm;

[0118] 5) Anode layer preparation

[0119] In high vacuum (1×10 -6 Ag was evaporated onto the anode buffer layer at 400 mbar to form an anode layer with a thickness of about 100 nm.

[0120] 6) Packaging

[0121] The devices were encapsulated with UV-curable resin in a nitrogen glove box.

[0122] Device Examples 2-4:

[0123] The preparation methods of device examples 2-4 are the same as those of device example 1, except that the choice of acceptor material in the photoactive layer is different. Specifically, the acceptor material compound (N-1) in device example 1 is replaced by compound (N-2), compound (N-8) and compound (N-10), respectively. See Table 1 for details.

[0124] Device Comparative Example 1-2

[0125] The preparation method of device comparative example 1-2 is the same as that of device example 1, except that the choice of acceptor material in the photoactive layer is different. Specifically, the acceptor material compound (N-1) in device example 1 is replaced by compound (Ref-1) and compound (Ref-2), respectively. See Table 1 for details.

[0126]

[0127] The prepared organic photovoltaic device was tested for performance under indoor light, the battery current-voltage curve was tested under a 3000K LED light source (1000 lux) simulator, and the photoelectric conversion efficiency was calculated, as shown in Table 1.

[0128] Table 1

[0129] Device Embodiment Photoactive layer donor and acceptor materials Photoelectric conversion efficiency (%) Device Example 1 D18: Compound (N-1) 26.35 Device Example 2 D18: Compound (N-2) 26.84 Device Example 3 D18: Compound (N-8) 27.61 Device Example 4 D18: Compound (N-10) 27.23 Device Comparative Example 1 D18: Compound (Ref-1) 24.55 Device Comparative Example 2 D18: Compound (Ref-2) 22.39

[0130] According to the data in Table 1, the reason why the effects of device examples 3 and 4 are better than those of device examples 1 and 2 is that the NFA described by the general formula (II-2) can form more charge transfer channels in its blend with the polymer donor relative to the NFA described by the general formula (II-1), thereby facilitating the transfer of charges.

[0131] The reason why the efficiency of the device in comparison with Example 2 is too low is that the branched alkyl group connected to N is too long. The too long branched alkyl group will cause the molecular plane of the small molecule receptor material to be distorted, thereby affecting the molecular morphology and stacking of the receptor.

[0132] The reason why the device effects of device embodiments 1-4 are better than those of device comparison embodiments 1-2 is that the non-fullerene acceptor material and the polymer donor material described in the present invention have a more suitable energy level combination in the active layer, forming a more suitable nanoscale size aggregation and a more favorable face-up molecular stacking orientation, thereby achieving better device effects under indoor light conditions.

[0133] Device Example 5

[0134] The preparation method of device example 5 is the same as that of device example 1, except that the photoactive layer material solution is different. Specifically, the preparation method of the photoactive layer material solution is as follows: the donor material in the photoactive layer material solution is selected from polymer PM6; the acceptor material is selected from compound (N-2) and compound (S-2); polymer PM6: compound (N-2): compound (S-2) are added to a chloroform solution at a mass ratio of 1:0.2:1, and the total concentration is 16.5 mg / mL. See Table 2 for details.

[0135] Device Example 6

[0136] The preparation method of the device embodiment is the same as that of the device embodiment 5, except that the photoactive layer material solution is different. Specifically, the preparation method of the photoactive layer material solution is as follows: the donor material in the photoactive layer material solution is selected from polymer PM6; the acceptor material is selected from compound (N-8) and compound (S-2); polymer PM6: compound (N-8): compound (S-2) are added to the chloroform solution at a mass ratio of 1:0.2:1, and the total concentration is 16.5 mg / mL. See Table 2 for details.

[0137] Device Comparison Example 3:

[0138] The preparation method of device comparative example 3 is the same as that of device example 5, except that the photoactive layer material solution is different. Specifically, the preparation method of the photoactive layer material solution is as follows: the donor material in the photoactive layer material solution is selected from polymer PM6; the acceptor material is selected from compound (S-2); polymer PM6: compound (S-2) are added to a chloroform solution at a mass ratio of 1:1.2, and the total concentration is 16.5 mg / mL. See Table 2 for details.

[0139] The prepared organic photovoltaic device was tested for performance under indoor light, the battery current-voltage curve was tested under a 3000K LED light source (1000 lux) simulator, and the photoelectric conversion efficiency was calculated, as shown in Table 2.

[0140] Table 2

[0141]

[0142] According to the data in Table 2, the device embodiments 5 and 6 are better than the device comparison embodiment 3. The reason is that the mixture described in the present invention comprises a first compound and a second compound, wherein the first compound and the second compound have the same core condensed ring skeleton and are highly miscible, which is very beneficial for achieving efficient synergistic effects in balancing crystallization dynamics, changing phase separation and charge carrier transport behavior, thereby exhibiting stronger exciton dissociation ability, higher carrier mobility and more efficient charge extraction in OPV battery devices.

[0143] from Figure 2 It can be seen from the JV curve that the multi-OPV device prepared by adding the first compound of the present application to the PM6: compound (S-2) system has greatly improved the fill factor (FF) of the device after testing, thereby achieving better optoelectronic performance.

[0144] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, a variety of simple modifications can be made to the technical solution of the present application, and these simple modifications all belong to the protection scope of the present application.

Claims

1. A non-fullerene acceptor material, characterized in that: Having a structure as shown in general formula (I): in: Selected from structural formula (A-1) or (A-2): represents the junction site; Y is selected from S or Se; Each occurrence of Z is independently selected from S or Se; Each occurrence of R1 is independently selected from a branched chain alkyl group having 8 to 12 carbon atoms; Each occurrence of R2 is independently selected from branched chain alkyl groups having 8 to 20 carbon atoms.

2. The non-fullerene acceptor material according to claim 1, characterized in that: The non-fullerene acceptor material is selected from the structure shown in the general formula (II-1) or (II-2):

3. The non-fullerene acceptor material according to claim 2, characterized in that: The R2 is selected from 4. The non-fullerene acceptor material according to claim 2, characterized in that: Each occurrence of R1 is independently selected from 5. The non-fullerene acceptor material according to claim 1, characterized in that: The non-fullerene acceptor material is selected from the following structures:

6. A mixture, characterized in that: The mixture comprises the non-fullerene acceptor material according to any one of claims 1-5.

7. The mixture according to claim 6, comprising at least a first compound and a second compound, characterized in that: The first compound is selected from the non-fullerene acceptor material according to any one of claims 1 to 5, and the second compound is selected from the structure described in general formula (III): in: Y1 is selected from S or Se; Each occurrence of Z1 is independently selected from S or Se; Each occurrence of R3 is independently selected from a branched chain alkyl group having 8 to 12 carbon atoms; Each occurrence of R4 is independently selected from branched chain alkyl groups having 8 to 20 carbon atoms.

8. The mixture according to claim 7, characterized in that: The second compound is selected from the structure described by general formula (IV):

9. The mixture according to claim 7, characterized in that: The second compound is selected from the following structures:

10. The mixture according to claim 9, characterized in that: The first compound is selected from compound (N-2) or (N-8); the second compound is selected from compound (S-2).

11. An organic photovoltaic cell, characterized in that: The organic photovoltaic cell comprises the non-fullerene acceptor material according to any one of claims 1 to 5 or the mixture according to any one of claims 6 to 10.

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