A non-fused-ring small molecule material and its application in organic solar cells

Abstract

This invention relates to the field of organic solar cell materials, and discloses a non-fused-ring small molecule material and its application in organic solar cells. The non-fused-ring small molecule material has a structure as shown in general formula (I). In this invention, the conformation of the non-fused-ring acceptor is locked by introducing S-N and S-O non-covalent bonds, thereby effectively restricting the rotation of C-C single bonds, achieving ordered molecular stacking and efficient electron transport, and thus improving device performance while reducing the material synthesis cost. When applied to organic solar cell devices, it achieves high photoelectric conversion efficiency.

Description

Technical Field

[0001] This invention relates to the field of organic solar cell materials, specifically to a non-fused ring small molecule material and its application in organic solar cells. Background Technology

[0002] Organic photovoltaic (OPV) cells are lightweight, semi-transparent, flexible, and offer advantages such as flexibility and designability. They are easy to fabricate in large areas and can be controlled on demand, making them a promising new generation of photovoltaic technology with broad application prospects. They can be widely used in wearable devices, smart IoT, smart homes, smart agriculture, building-integrated photovoltaics, and vehicle-mounted photovoltaics.

[0003] With the continuous development and improvement of molecular design strategies, especially the successful development of Y-type fused-ring electron acceptors such as Y6, L8-BO, and BTP-eC9, the performance of OPV devices has made significant progress in the past few years, with photoelectric conversion efficiency (PCE) approaching 20%. However, Y-type fused-ring acceptors contain a large fused-ring core, and the synthesis route is long and the material cost is high, which greatly limits the industrial application of organic photovoltaics.

[0004] In recent years, the development of non-fused-ring small molecule acceptor materials has received increasing attention. Compared with fused-ring small molecule acceptors, non-fused-ring small molecule acceptors have the advantages of simple structure and ease of synthesis, greatly reducing the complexity of material synthesis and production costs. However, compared with fused-ring small molecule acceptors, non-fused-ring small molecule acceptor materials can undergo rotation through C-C single bonds, resulting in conformational isomers and distorted configurations that disrupt the coplanarity of the molecular backbone. This, in turn, affects the molecular aggregation morphology, reducing the photoelectric properties of the material and the photoelectric conversion efficiency of the device.

[0005] To address the issue of poor planarity in non-fused-ring small molecule acceptors, CN113880829A proposes utilizing the conformational locking effect of large steric hindrance groups to restrict the free rotation of the conjugated backbone, thereby improving the planarity of the backbone structure. CN115650971A discloses a non-fused-ring small molecule acceptor with bithiazole as the central unit. By introducing a large steric hindrance group, a phenyl aromatic ring, at the side chain position of the central thiophene unit, the non-fused-ring small molecule acceptor can form a stable planar structure, enhancing the delocalization of π electrons and intramolecular and intermolecular transfer. Furthermore, the intermolecular van der Waals forces facilitate the formation of a conjugated structure, resulting in a non-fused-ring electron acceptor with higher electron transfer efficiency.

[0006] However, the synthesis of such compounds is difficult due to the excessive steric hindrance of their core structures. Therefore, it is necessary to develop novel non-fused-ring small molecule acceptor materials to overcome the shortcomings of existing technologies. Summary of the Invention

[0007] Based on the problems existing in the prior art, the present invention provides a novel non-fused ring small molecule material. By introducing S-N and S-O non-covalent bonds, the conformation of the non-fused ring acceptor is locked, thereby effectively restricting the rotation of C-C single bonds, achieving ordered molecular stacking and efficient electron transport, and thus improving device performance while reducing the material synthesis cost.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A non-fused-ring small molecule material having a structure as shown in general formula (I):

[0010]

[0011] in:

[0012] R1, R2, and R3 are each independently selected from -H, -D, -F, -Cl, -Br, -I, -CN, -CF3, -NO2, straight-chain alkyl with 1-20 carbon atoms, branched alkyl with 3-20 carbon atoms, straight-chain alkoxy with 1-20 carbon atoms, branched alkoxy with 3-20 carbon atoms, straight-chain alkylthio with 1-20 carbon atoms, or branched alkylthio with 3-20 carbon atoms.

[0013] Each time R4 appears, it is independently selected from straight-chain alkyl groups having 1-20 carbon atoms or branched alkyl groups having 3-20 carbon atoms;

[0014] Ar1 and Ar2 are independently selected from unsubstituted or synthesized by one or more R... * Substituted aromatic groups having 6-10 carbon atoms, or unsubstituted or substituted with one or more R atoms. * Substituted heteroaromatic groups having 5-10 ring atoms;

[0015] R * Each occurrence is independently selected from -D, -F, -Cl, -Br, -I, -CN, -CF3, -NO2, straight-chain alkyl with 1-10 carbon atoms, branched-chain alkyl with 3-10 carbon atoms, straight-chain alkoxy with 1-10 carbon atoms, branched-chain alkoxy with 3-10 carbon atoms, straight-chain alkylthio with 1-10 carbon atoms, or branched-chain alkylthio with 3-10 carbon atoms.

[0016] This invention creatively introduces a side-chain thiophene group into the core thiophene group. The S atom on the side-chain thiophene and the N atom on the main-chain thiazole are conformationally locked through an S-N non-covalent bond, thereby effectively restricting the rotation of the C-C single bond. To further achieve molecular order, this invention further introduces an alkoxy substitution onto the main-chain thiophene, while an S-O non-covalent bond achieves conformational locking between thiophene and thiazole. The non-fused-ring small molecule material described in this invention exhibits good molecular packing and efficient electron transport, thus achieving high photoelectric conversion efficiency when used as a photoactive layer acceptor material in organic solar cell devices.

[0017] In some embodiments, Ar1 and Ar2 are independently selected from the following groups:

[0018]

[0019] Wherein: n1 appears each time, independently selected from 0, 1, 2, 3 or 4; n2 appears each time, independently selected from 0, 1, 2, 3, 4, 5 or 6; n3 appears each time, independently selected from 0, 1 or 2;

[0020] * indicates a fusion site, which is selected from C atoms.

[0021] In some embodiments, Ar1 and Ar2 are independently selected from the following groups:

[0022]

[0023] Wherein: n1 appears each time, independently selected from 0, 1, 2, 3 or 4; n2 appears each time, independently selected from 0, 1, 2, 3, 4, 5 or 6; n3 appears each time, independently selected from 0, 1 or 2;

[0024] * indicates a fusion site, which is selected from C atoms.

[0025] In some embodiments, the non-fused-ring small molecule material is selected from any structure of general formulas (II-1)-(II-4):

[0026]

[0027] In some implementations, the R * Each occurrence is independently selected from -D (deuterium), -F, -Cl, -Br, -I, -CN, -CF3, -NO2, straight-chain alkyl with 1-6 carbon atoms, branched alkyl with 3-6 carbon atoms, straight-chain alkoxy with 1-6 carbon atoms, branched alkoxy with 3-6 carbon atoms, straight-chain alkylthio with 1-6 carbon atoms, or branched alkylthio with 3-16 carbon atoms.

[0028] In some implementations, the R* Each occurrence is independently selected from -D, -F, -Cl, -Br, -I, -CN, -CF3, -NO2, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, cyclopentyl, cyclohexyl, methoxy, or methylthio.

[0029] In some implementations, in formula II-1 Selected from any of the following groups:

[0030]

[0031] Where: # represents the connection site.

[0032] In some implementations, in formula II-2 Selected from any of the following groups:

[0033]

[0034] In some implementations, in formula II-3 Selected from any of the following groups:

[0035]

[0036] In some implementations, in formula II-4 Selected from any of the following groups:

[0037]

[0038] In some embodiments, each occurrence of R1 is independently selected from straight-chain alkyl groups having 1-16 carbon atoms, branched alkyl groups having 3-16 carbon atoms, straight-chain alkoxy groups having 1-16 carbon atoms, branched alkoxy groups having 3-16 carbon atoms, straight-chain alkylthio groups having 1-16 carbon atoms, or branched alkylthio groups having 3-16 carbon atoms.

[0039] In some embodiments, each time R2 and R3 appear, they are independently selected from -H, -D, -F, -Cl, -Br, -I, -CN, -CF3, -NO2, straight-chain alkyl with 1-10 C atoms, and branched alkyl with 3-10 C atoms;

[0040] In some embodiments, each occurrence of R4 is independently selected from straight-chain alkyl groups having 4-20 carbon atoms or branched alkyl groups having 4-20 carbon atoms.

[0041] In some embodiments, each occurrence of R4 is independently selected from straight-chain alkyl groups having 4-10 carbon atoms or branched alkyl groups having 4-10 carbon atoms.

[0042] In some implementations, each occurrence of R2 is independently selected from -H, -D, -F, -Cl, -Br, -I, -CN, or -CF3.

[0043] In some implementations, R3 is selected independently from -H, -D, or -F each time it appears.

[0044] In some implementations, R2 and R3 are selected from -H each time they appear.

[0045] In one embodiment, each occurrence of R1 is independently selected from straight-chain alkyl groups having 1-10 C atoms or branched alkyl groups having 3-10 C atoms; and R2 and R3 are selected from -H.

[0046] In some embodiments, the non-fused-ring small molecule material is selected from the following structures:

[0047]

[0048]

[0049] The present invention further relates to a photoactive layer acceptor material, wherein the photoactive layer acceptor material is selected from the non-fused ring small molecule materials described above.

[0050] The present invention also provides a mixture comprising a photoactive layer donor material and a photoactive layer acceptor material, wherein the photoactive layer acceptor material is selected from the non-fused-ring small molecule materials described above.

[0051] In some embodiments, the photoactive layer donor material is selected from one or more of PBDB-T, PM6, PM7, D18, D18-Cl, PBQx-TCl, PTQ10, and PTQ11, but is not limited thereto; commonly used donor materials in the art may also be included.

[0052] In some embodiments, the mixture according to the present invention has a mass ratio of photoactive layer donor material to photoactive layer acceptor material of 1:1 to 1:1.8; preferably, the mass ratio is 1:1 to 1:1.5; preferably, the mass ratio is 1:1 to 1:1.2.

[0053] The present invention also provides a composition comprising the above-mentioned non-fused-ring small molecule material or mixture, and at least one organic solvent.

[0054] In some embodiments, the organic solvent is selected from chlorobenzene, toluene, o-xylene, or chloroform, but is not limited thereto.

[0055] In some embodiments, the concentration of the mixture in the organic solvent according to the present invention is selected from 6-30 mg / mL; further, the concentration of the mixture in the organic solvent is selected from 6-20 mg / mL.

[0056] Furthermore, the composition further comprises an additive, which may be selected from liquid additives or solid additives.

[0057] Preferably, the additive is selected from 1,8-diiodooctane (DIO), diphenyl ether (DPE), anthracene, or one or more halogen-substituted phenyl groups; preferably, the one or more halogen-substituted phenyl groups are selected from 1,4-diiodobenzene (DIB), 1,3-dibromo-5-chlorobenzene (DBCl), 3,5-dichlorobromobenzene (DCBB), 1-chloronaphthalene (1-CN), 1,3,5-tribromobenzene (TBB), etc., but are not limited thereto.

[0058] The present invention also provides an organic solar cell device, the organic solar cell device comprising at least a cathode, an anode, and a photoactive layer located between the cathode and the anode, wherein the photoactive layer material comprises the non-fused-ring small molecule material or mixture described above, or is prepared from the above composition.

[0059] Materials used to prepare electrodes (cathode and anode) can be selected from metals, such as vanadium (V), chromium (Cr), zinc (Zn), silver (Ag), aluminum (Al), platinum (Pt), tungsten (W), copper (Cu), molybdenum (Mo), gold (Au), nickel (Ni), palladium (Pd), or alloys of the above metals; conductive nanomaterials, such as metal nanowires, nanoparticle slurries, graphene, carbon nanotubes, etc.; metal oxides, such as zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), etc.; combinations of metals and oxides, such as ZnO∶Al or SnO2∶Sb, etc.; and conductive polymers, such as PEDOT:PSS, polypyrrole, and polyaniline, etc.; or materials with multilayer structures, such as LiF / Al, LiO2 / Al, LiF / Fe, MoO3 / Al, Al∶Li, Al∶BaF2, and Al∶BaF2∶Ba, etc., but not limited to these.

[0060] The materials used to prepare the photoactive layer can be selected from the mixtures or compositions described above.

[0061] In some embodiments, the thickness of the photoactive layer is 50–300 nm; further, the thickness of the photoactive layer is 50–150 nm.

[0062] Furthermore, the organic solar cell device further includes an anode buffer layer located between the anode and the photoactive layer.

[0063] Furthermore, the anode buffer layer material is selected from PEDOT:PSS, molybdenum oxide (MoOx), vanadium oxide (V2O5), nickel oxide (NiOx), tungsten oxide (WOx, preferably, x is selected from 2 or 3), or self-assembled materials, such as 2PACz, MeO-2PACz, etc., but is not limited thereto.

[0064] Furthermore, the organic solar cell device further includes a cathode buffer layer located between the cathode and the photoactive layer.

[0065] Furthermore, the cathode buffer layer material is selected from metal oxides or polymers. The metal oxides may be metal complexes containing 8-hydroxyquinoline, complexes containing Alq3, metal complexes containing Liq, LiF, Ca, titanium oxide (TiOx), zinc oxide (ZnO), cesium carbonate (Cs2CO3), etc., and the polymers may be PFN-Br, PFN, PDINN, PDINO, PNDIT-F3N-Br or PNDIT-F3N, etc., but are not limited to these.

[0066] It should be noted that, in order to improve the performance of organic solar cell devices, the functional layer may further include other functional layers, including but not limited to a charge blocking layer.

[0067] In some embodiments, the organic solar cell further includes a substrate. Specifically, the substrate may be disposed on one side of the anode and on a different side from the photoactive layer.

[0068] In some embodiments, the organic solar cell further includes a substrate. Specifically, the substrate may be disposed on one side of the cathode and on a different side from the photoactive layer.

[0069] Specifically, the substrate can be a substrate with excellent transparency, surface smoothness, ease of handling, and water resistance. For example, a glass substrate, a thin-film glass substrate, or a transparent plastic substrate can be used. The plastic substrate may include, but is not limited to, single-layer or multi-layer films such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyetheretherketone (PEEK), and polyimide (PI), and substrates commonly used in organic solar cells may also be used.

[0070] The organic solar cell device according to the present invention can be applied to wearable devices, smart IoT, smart homes, smart agriculture, building photovoltaics, vehicle photovoltaics and other fields.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] (1) The non-fused ring small molecule in this invention uses thiophene-thiophene as the core group and introduces the side chain of the thiophene group. It achieves conformational locking through S---N non-covalent bonds, thereby effectively restricting the rotation of C-C single bonds and improving the orderliness of the molecule. This non-fused ring small molecule material has good molecular stacking and efficient electron transport. When it is used as a photoactive layer acceptor material in organic solar cell devices, it achieves high photoelectric conversion efficiency.

[0073] (2) The preparation method of non-fused ring small molecules in this invention is simple, the raw materials are cheap and readily available, the synthesis cost is low, and it is easy to mass-produce. Attached Figure Description

[0074] Figure 1 This is a schematic diagram of the structure of the organic solar cell device in the embodiment of the present invention. Detailed Implementation

[0075] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0076] In this invention, terms such as "further," "even more," and "particularly" are used for descriptive purposes and to indicate differences in content, but should not be construed as limiting the scope of protection of this invention.

[0077] In this invention, "optionally," "optionally," and "optional" mean that they are optional, that is, they are selected from either "with" or "without." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent.

[0078] In the description of this invention, it should be understood that the terms "upper," "lower," "between layers," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when organic solar cell devices are in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0079] In this invention, when the position of the substituent on the group is not fixed, it means that any connectable site in the group can serve as a connection site. For example... Can represent

[0080] In this invention, organic photovoltaic devices, organic solar cells, and OPV have the same meaning and can be used interchangeably.

[0081] In this invention, the active layer and the photoactive layer have the same meaning and can be used interchangeably.

[0082] In this invention, "alkyl" can refer to straight-chain, branched, and / or cyclic alkyl groups. The number of carbon atoms in a straight-chain alkyl group can be 1 to 20, 1 to 16, 1 to 10, 1 to 6, or 1 to 4; the number of carbon atoms in a branched-chain alkyl group can be 3 to 20, 3 to 16, 3 to 10, 3 to 6, or 3 to 4; and the number of carbon atoms in a cyclic alkyl group can be 3 to 20, 3 to 16, 3 to 10, 3 to 6, or 3 to 4. Non-limiting examples of straight-chain alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl; non-limiting examples of branched-chain alkyl groups include isopropyl, tert-butyl, sec-butyl, tert-butyl, isobutyl, 2-ethylbutyl, 3,3-dimethylbutyl, isopentyl, neopentyl, and tert-pentyl.

[0083] The term "alkoxy" refers to a group with the structure "-O-alkyl", that is, an alkyl group as defined above that is attached to other groups via an oxygen atom. The straight-chain alkoxy means that the alkyl group in "-O-alkyl" is selected from straight-chain alkyl groups, wherein the number of carbon atoms in the straight-chain alkyl group can be 1 to 20, 1 to 16, 1 to 10, 1 to 6, or 1 to 4; the branched-chain alkoxy means that the alkyl group in "-O-alkyl" is selected from branched-chain alkyl groups, wherein the number of carbon atoms in the branched-chain alkyl group can be 3 to 20, 3 to 16, 3 to 10, 3 to 6, or 3 to 4.

[0084] The term "alkoxythio" refers to a group with the structure "-S-alkyl", that is, an alkyl group as defined above that is attached to other groups via a sulfur atom. The straight-chain alkoxythio group indicates that the alkyl group in the "-S-alkyl" is selected from straight-chain alkyl groups, wherein the number of carbon atoms in the straight-chain alkyl group can be 1 to 20, 1 to 16, 1 to 10, 1 to 6, or 1 to 4; the branched-chain alkoxythio group indicates that the alkyl group in the "-S-alkyl" is selected from branched-chain alkyl groups, wherein the number of carbon atoms in the branched-chain alkyl group can be 3 to 20, 3 to 16, 3 to 10, 3 to 6, or 3 to 4.

[0085] In this invention, "ring atom number" refers to the number of atoms in the ring-forming atoms of a structural compound (e.g., monocyclic compound, fused-ring compound, cross-linked compound, carbocyclic compound, heterocyclic compound) obtained by atomic bonding to form a ring. When the ring is substituted by a substituent, the atoms contained in the substituent are not included in the ring-forming atoms. The same applies to the "ring atom number" described below unless otherwise specified. In aromatic groups, the ring atom number is the same as the carbon atom number; in heteroaromatic groups, the ring atom number is the carbon atom number plus the heteroatom number; for example, the ring atom number of a benzene ring is 6, the ring atom number of a naphthalene ring is 10, the ring atom number of a quinoline ring is 10, the ring atom number of a thiophene group is 5, and the ring atom number of a thiophene is 8.

[0086] In describing the structural elements of the present invention, the terms "comprising," "including," or "at least one" as used in the present invention mean that the device or material preceding the word covers the device or material listed after the word and its equivalents, without excluding other devices or materials.

[0087] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0088] The present invention will now be described in conjunction with preferred embodiments, but the present invention is not limited to the following embodiments. It should be understood that the appended claims summarize the scope of the present invention. Under the guidance of the inventive concept, those skilled in the art should realize that any 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.

[0089] Synthesis Example 1: Synthesis of compound (2), the reaction formula is shown below:

[0090]

[0091] Synthesis of Compounds 2-3

[0092] Compounds 2-1 (59.5 g, 0.3 mol), 2-2 (165.4 g, 0.33 mol), and tetraphenylphosphine palladium (3.5 g, 3 mmol) were added sequentially to a 2000 mL three-necked flask. 1000 mL of anhydrous toluene was added, and the mixture was purged with argon three times. The temperature was then raised to 90 °C and reacted for 12 hours. The reaction was monitored by TLC until completion. The reaction solution was cooled to room temperature, and water was added to separate the phases. The aqueous phase was extracted twice with ethyl acetate. The combined organic phases were washed with saturated brine, separated, and dried over anhydrous sodium sulfate. The filtrate was mixed and evaporated to dryness, then separated by silica gel column chromatography with PE:DCM = 15:1 (v / v). Approximately 70.6 g of compound 2-3 was obtained, yielding 71.3% (MS: 329.77).

[0093] Synthesis of compounds 2-6

[0094] Compounds 2-4 (29.8 g, 0.1 mol), 2-5 (71.8 g, 0.2 mol), and tetraphenylphosphine palladium (2.3 g, 2 mmol) were added sequentially to a 1000 mL three-necked flask. 500 mL of anhydrous toluene was added, and the mixture was purged with argon three times. The temperature was then raised to 110 °C and reacted for 6 hours. The reaction was monitored by TLC until completion. The reaction solution was cooled to room temperature, and water was added to separate the phases. The aqueous phase was extracted twice with ethyl acetate. The combined organic phases were washed with saturated brine, separated, and dried over anhydrous sodium sulfate. The organic phase was filtered. The filtrate was mixed with water and evaporated to dryness. Separation was performed by silica gel column chromatography using PE as the eluent, yielding approximately 40.7 g of compound 2-6 (76.9% yield, MS: 528.80).

[0095] Synthesis of compounds 2-8

[0096] Compounds 2-6 (37.0 g, 70 mmol) and 450 mL of anhydrous tetrahydrofuran were added sequentially to a 1000 mL three-necked flask. After purging with argon three times, the mixture was cooled to -78 °C in a liquid nitrogen ethanol bath. Butyllithium (2.5 M, 70 mL) was slowly added dropwise to the reaction system, and the reaction was maintained at -78 °C for 1 hour. Then, compound 2-7 (57.0 g, 175 mmol) was slowly added dropwise. After half an hour, the ice bath was removed, and the mixture was allowed to naturally return to room temperature for 2 hours. The reaction solution was then quenched in water. The mixture was separated, and the aqueous phase was extracted twice with ethyl acetate. The combined organic phases were washed with saturated brine, separated, and dried over anhydrous sodium sulfate. The organic phase was then filtered. The filtrate was mixed and evaporated to dryness, and then separated by vacuum neutral alumina column chromatography with n-hexane as the eluent, yielding approximately 47.5 g of compound 2-8 (61.3% yield, MS: 1106.72).

[0097] Synthesis of compounds 2-9

[0098] Compounds 2-8 (44.3 g, 40 mmol), 2-3 (28.0 g, 85 mmol), and tetraphenylphosphine palladium (1.85 g, 1.6 mmol) were added sequentially to a 500 mL three-necked flask. 250 mL of anhydrous toluene was added, and the mixture was purged with argon three times. The temperature was then raised to 110 °C and reacted for 12 hours. The reaction was monitored by TLC until completion. The reaction solution was cooled to room temperature, and water was added to separate the phases. The aqueous phase was extracted twice with ethyl acetate. The combined organic phases were washed with saturated brine, separated, and dried over anhydrous sodium sulfate. The filtrate was mixed and evaporated to dryness, then separated by silica gel column chromatography with PE:DCM = 15:1 (v / v). Approximately 28.3 g of compound 2-9 was obtained, yielding 63.5% (MS: 1115.46).

[0099] Synthesis of Compound 2-10

[0100] Compound 2-9 (22.3 g, 20 mmol) was added to a 500 mL three-necked flask, followed by the addition of 200 mL anhydrous DMF. After purging with argon three times, the mixture was cooled to 0 °C in an ice-salt bath. Phosphorus oxychloride (15.3 g, 100 mmol) was then slowly added dropwise to the reaction system. After the addition was complete, the mixture was stirred at 0 °C for 1 h, and then heated to 80 °C for 12 h. The mixture was cooled to room temperature, and the reaction solution was quenched in water. The mixture was extracted three times with dichloromethane, and the combined organic phases were dried over anhydrous sodium sulfate. Excess solvent was removed by vacuum distillation. The mixture was then subjected to silica gel column chromatography with a PE:DCM eluent ratio of 10:1 (v / v), yielding approximately 18.4 g of compound 2-10 (yield: 78.6%, MS: 1171.84).

[0101] Synthesis of compound (2):

[0102] Compound 2-10 (2.9 g, 2.5 mmol), compound 2-11 (1.2 g, 5.2 mmol), and piperidine (5.0 mL) were added sequentially to a 250 mL three-necked flask. 100 mL of chloroform was added, and the mixture was purged with argon three times. The temperature was then raised to 60 °C and reacted for 12 h. After cooling to room temperature, excess solvent was removed by vacuum distillation. The crude product was washed with 100 mL of methanol, filtered, and the filter cake was dissolved in dichloromethane and then subjected to silica gel chromatography with a PE:DCM ratio of 6:1 (volume ratio). Approximately 2.7 g of compound (2) was obtained, yield: 68.3%, MALDI-TOF-MS: 1596.24.

[0103] Synthesis Example 2: Synthesis of Compound (7)

[0104]

[0105] Synthesis of compound 7-3

[0106] Compound 7-1 (42.9 g, 0.2 mol) and 400 mL of anhydrous tetrahydrofuran were added sequentially to a 1000 mL three-necked flask. After purging with argon three times, the mixture was cooled to -78 °C in a liquid nitrogen ethanol bath. Diisopropylaminolithium (2 M, 150 mL) was slowly added dropwise to the reaction system, and the reaction was maintained at -78 °C for 1 hour. Then, compound 7-2 (64.3 g, 0.3 mol) was slowly added dropwise to the reaction system. After half an hour, the liquid nitrogen ethanol bath was removed, and the mixture was allowed to naturally return to room temperature for 2 hours. The reaction solution was then quenched in water. The mixture was separated, and the aqueous phase was extracted twice with ethyl acetate. The organic phases were combined, washed with saturated brine, separated, and dried over anhydrous sodium sulfate. The organic phase was then filtered. The filtrate was mixed with water, evaporated to dryness, and separated by vacuum neutral alumina column chromatography using petroleum ether as the eluent, yielding approximately 62.4 g of compound 7-3, with a yield of 82.7%. MS: 377.42.

[0107] Synthesis of compound 7-4

[0108] Compounds 7-3 (60.3 g, 160 mmol), 2-4 (23.8 g, 80 mol), and tetraphenylphosphine palladium (3.7 g, 3.2 mmol) were added sequentially to a 1000 mL three-necked flask. 500 mL of anhydrous toluene was added, and the mixture was purged with argon three times. The temperature was then raised to 110 °C and reacted for 12 hours. The reaction was monitored by TLC until completion. The reaction mixture was cooled to room temperature, and water was added to separate the phases. The aqueous phase was extracted twice with ethyl acetate. The combined organic phases were washed with saturated brine, separated, and dried over anhydrous sodium sulfate. The filtrate was mixed and evaporated to dryness, then separated by silica gel column chromatography with PE:DCM = 20:1 (v / v). Approximately 34.6 g of compound 7-4 was obtained, with a yield of 76.5%. MS: 565.03. Synthesis of compound 7-5

[0109] Compound 7-4 (28.2 g, 50 mmol) and 400 mL of anhydrous tetrahydrofuran were added sequentially to a 1000 mL three-necked flask. After purging with argon three times, the mixture was cooled to -78 °C in a liquid nitrogen ethanol bath. 2.5 M, 50 mL of n-butyllithium was slowly added dropwise to the reaction system, and the reaction was maintained at -78 °C for 1 hour. Then, compound 2-7 (40.7 g, 175 mmol) was slowly added dropwise. After half an hour, the ice bath was removed, and the mixture was allowed to naturally return to room temperature for 2 hours. The reaction solution was then quenched in water. The mixture was separated, and the aqueous phase was extracted twice with ethyl acetate. The combined organic phases were washed with saturated brine, separated, and dried over anhydrous sodium sulfate. The organic phase was then filtered. The filtrate was mixed and evaporated to dryness, and then separated by vacuum neutral alumina column chromatography with n-hexane as the eluent, yielding approximately 44.3 g of compound 7-5 (77.5%). MALDI-TOF-MS: 1143.12.

[0110] Synthesis of Compounds 7-6

[0111] Compounds 7-5 (17.1 g, 15 mmol), 2-3 (21.4 g, 32 mmol), and tetraphenylphosphine palladium (1.85 g, 1.6 mmol) were added sequentially to a 500 mL three-necked flask. 250 mL of anhydrous toluene was added, and the mixture was purged with argon three times. The temperature was then raised to 110 °C and reacted for 12 hours. The reaction was monitored by TLC until completion. The reaction solution was cooled to room temperature, and water was added to separate the phases. The aqueous phase was extracted twice with ethyl acetate. The combined organic phases were washed with saturated brine, separated, and dried over anhydrous sodium sulfate. The filtrate was mixed and evaporated to dryness, then separated by silica gel column chromatography with PE:DCM = 10:1 (v / v). Approximately 14.2 g of compound 7-6 was obtained, with a yield of 82.4%. MALDI-TOF-MS: 1151.86.

[0112] Synthesis of compound 7-7

[0113] Compound 7-6 (11.5 g, 10 mmol) was added to a 500 mL three-necked flask, followed by the addition of 200 mL anhydrous DMF. After purging with argon three times, the mixture was cooled to 0 °C in an ice-salt bath. Phosphorus oxychloride (7.6 g, 50 mmol) was weighed and slowly added dropwise to the reaction system. After the addition was complete, the mixture was stirred at 0 °C for 1 h, then heated to 80 °C and reacted for 12 h. The mixture was cooled to room temperature, and the reaction solution was quenched in water. The mixture was extracted three times with dichloromethane, and the combined organic phases were dried over anhydrous sodium sulfate. Excess solvent was removed by vacuum distillation. The mixture was then subjected to silica gel column chromatography with a PE:DCM eluent ratio of 15:1 (v / v), yielding approximately 8.9 g of compound 7-7 (73.6%). MALDI-TOF-MS: 1207.91.

[0114] Synthesis of compound (7):

[0115] Compound 7-7 (3.0 g, 2.5 mmol), compound 2-11 (1.2 g, 5.2 mmol), and piperidine (5.0 mL) were added sequentially to a 250 mL three-necked flask. 100 mL of chloroform was added, and the mixture was purged with argon three times. The temperature was then raised to 60 °C and reacted for 12 h. After cooling to room temperature, excess solvent was removed by vacuum distillation. The crude product was washed with 100 mL of methanol, filtered, and the filter cake was dissolved in dichloromethane and then subjected to silica gel chromatography with a PE:DCM ratio of 15:1 (volume ratio). Approximately 2.6 g of compound (7) was obtained, with a yield of 63.7%. MALDI-TOF-MS: 1632.49.

[0116] Synthesis Example 3: Synthesis of Compound (10)

[0117]

[0118] Synthesis of compound (10):

[0119] Compound 2-10 (2.9 g, 2.5 mmol), compound 10-1 (1.4 g, 5.2 mmol), and piperidine (5.0 mL) were added sequentially to a 250 mL three-necked flask. 100 mL of chloroform was added, and the mixture was purged with argon three times. The temperature was then raised to 60 °C and reacted for 12 h. After cooling to room temperature, excess solvent was removed by vacuum distillation. The crude product was washed with 150 mL of methanol, filtered, and the filter cake was dissolved in dichloromethane and then subjected to silica gel chromatography with a PE:DCM ratio of 20:1 (volume ratio). Approximately 2.4 g of compound (10) was obtained, with a yield of 58.4%. MALDI-TOF-MS: 1661.88.

[0120] Synthesis Example 4: Synthesis of Compound (17)

[0121]

[0122] Synthesis of compound (17):

[0123] Compound 2-10 (2.9 g, 2.5 mmol), compound 17-1 (1.5 g, 5.2 mmol), and piperidine (5.0 mL) were added sequentially to a 250 mL three-necked flask. 100 mL of chloroform was added, and the mixture was purged with argon three times. The temperature was then raised to 60 °C and reacted for 12 h. After cooling to room temperature, excess solvent was removed by vacuum distillation. The crude product was washed with 100 mL of methanol, filtered, and the filter cake was dissolved in dichloromethane and then subjected to silica gel chromatography with a PE:EA ratio of 25:1 (volume ratio). Approximately 2.6 g of compound (17) was obtained, with a yield of 61.2%. MALDI-TOF-MS: 1696.33.

[0124] Synthesis Example 5: Synthesis of Compound (22)

[0125]

[0126] Synthesis of compound (22):

[0127] Compound 2-10 (2.9 g, 2.5 mmol), compound 22-1 (1.1 g, 5.2 mmol), and piperidine (5.0 mL) were added sequentially to a 250 mL three-necked flask. 100 mL of chloroform was added, and the mixture was purged with argon three times. The temperature was then raised to 60 °C and reacted for 12 h. After cooling to room temperature, excess solvent was removed by vacuum distillation. The crude product was washed with 120 mL of methanol, filtered, and the filter cake was dissolved in dichloromethane and then subjected to silica gel chromatography with a PE:DCM:EA ratio of 40:2:1 (volume ratio). Approximately 2.6 g of compound (22) was obtained, yield: 68.5%. MALDI-TOF-MS: 1536.38.

[0128] Synthesis Example 6: Synthesis of Compound (31)

[0129]

[0130] Synthesis of compound (31):

[0131] Compound 2-10 (2.9 g, 2.5 mmol), compound 31-1 (1.5 g, 5.2 mmol), and piperidine (5.0 mL) were added sequentially to a 250 mL three-necked flask. 100 mL of chloroform was added, and the mixture was purged with argon three times. The temperature was then raised to 60 °C and reacted for 12 h. After cooling to room temperature, excess solvent was removed by vacuum distillation. The crude product was washed with 120 mL of methanol, filtered, and the filter cake was dissolved in dichloromethane and then subjected to silica gel chromatography with a PE:DCM ratio of 15:1 (volume ratio). Approximately 3.0 g of compound (31) was obtained, with a yield of 70.7%. MALDI-TOF-MS: 1694.02.

[0132] Synthesis Example 7: Synthesis of Compound (33)

[0133]

[0134] Synthesis of compound 33-2

[0135] Compound 33-1 (46.2 g, 0.2 mol) and 400 mL of anhydrous tetrahydrofuran were added sequentially to a 1000 mL three-necked flask. After purging with argon three times, the mixture was cooled to -78 °C in a liquid nitrogen ethanol bath. Diisopropylaminolithium (2 M, 150 mL) was slowly added dropwise to the reaction system, and the reaction was maintained at -78 °C for 1 hour. Then, compound 7-2 (64.3 g, 0.3 mol) was slowly added dropwise. After half an hour, the liquid nitrogen ethanol bath was removed, and the mixture was allowed to naturally return to room temperature for 2 hours. The reaction solution was then quenched in water. The mixture was separated, and the aqueous phase was extracted twice with ethyl acetate. The combined organic phases were washed with saturated brine, separated, and dried over anhydrous sodium sulfate. The organic phase was then filtered. The filtrate was mixed and evaporated to dryness, and then separated by vacuum neutral alumina column chromatography using dichloromethane as the eluent, yielding approximately 65.8 g of compound 33-2, with a yield of 83.6%. MS: 393.65

[0136] Synthesis of compound 33-3

[0137] Compounds 33-2 (63.0 g, 160 mmol), 2-4 (23.8 g, 80 mol), and tetraphenylphosphine palladium (3.7 g, 3.2 mmol) were added sequentially to a 1000 mL three-necked flask. 500 mL of anhydrous toluene was added, and the mixture was purged with argon three times. The temperature was then raised to 110 °C and reacted for 12 hours. The reaction was monitored by TLC until completion. The reaction solution was cooled to room temperature, and water was added to separate the phases. The aqueous phase was extracted twice with ethyl acetate. The combined organic phases were washed with saturated brine, separated, and dried over anhydrous sodium sulfate. The filtrate was mixed and evaporated to dryness, then separated by silica gel column chromatography with PE:DCM = 25:1 (v / v) as the eluent, yielding approximately 35 g of compound 33-3, with a yield of 73.2%. Ms: 597.48. Synthesis of compound 33-4.

[0138] Compound 33-3 (29.9 g, 50 mmol) and 400 mL of anhydrous tetrahydrofuran were added sequentially to a 1000 mL three-necked flask. After purging with argon three times, the mixture was cooled to -78 °C in a liquid nitrogen ethanol bath. 2.5 M, 50 mL of n-butyllithium was slowly added dropwise to the reaction system, and the reaction was maintained at -78 °C for 1 hour. Then, compound 2-7 (40.7 g, 175 mmol) was slowly added dropwise. After half an hour, the ice bath was removed, and the mixture was allowed to naturally return to room temperature for 2 hours. The reaction solution was then quenched in water. The mixture was separated, and the aqueous phase was extracted twice with ethyl acetate. The combined organic phases were washed with saturated brine, separated, and dried over anhydrous sodium sulfate. The organic phase was then filtered. The filtrate was mixed, evaporated to dryness, and separated by vacuum neutral alumina column chromatography with n-hexane as the eluent, yielding approximately 43.7 g of compound 33-4 (74.3%). MS: 1175.36.

[0139] Synthesis of compound 33-5

[0140] Compounds 33-4 (17.6 g, 15 mmol), 2-3 (21.4 g, 32 mmol), and tetraphenylphosphine palladium (1.85 g, 1.6 mmol) were added sequentially to a 500 mL three-necked flask. 250 mL of anhydrous toluene was added, and the mixture was purged with argon three times. The temperature was then raised to 110 °C and reacted for 12 hours. The reaction was monitored by TLC until completion. The reaction solution was cooled to room temperature, and water was added to separate the phases. The aqueous phase was extracted twice with ethyl acetate. The combined organic phases were washed with saturated brine, separated, and dried over anhydrous sodium sulfate. The filtrate was mixed and evaporated to dryness, then separated by silica gel column chromatography with PE:DCM = 15:1 (v / v). Approximately 14.1 g of compound 33-5 was obtained, with a yield of 79.6%. MALDI-TOF-MS: 1184.30.

[0141] Synthesis of compound 33-6

[0142] Compound 33-5 (11.8 g, 10 mmol) was added to a 500 mL three-necked flask, followed by the addition of 200 mL anhydrous DMF. After purging with argon three times, the mixture was cooled to 0 °C in an ice-salt bath. Phosphorus oxychloride (7.6 g, 50 mmol) was then slowly added dropwise to the reaction system. After the addition was complete, the mixture was stirred at 0 °C for 1 h, then heated to 80 °C and reacted for 12 h. The mixture was cooled to room temperature, and the reaction solution was quenched in water. The mixture was extracted three times with dichloromethane, and the combined organic phases were dried over anhydrous sodium sulfate. Excess solvent was removed by vacuum distillation. The mixture was then subjected to silica gel column chromatography with a PE:EA eluent ratio of 25:1 (v / v), yielding approximately 8.8 g of compound 33-6 (yield: 70.7%). MALDI-TOF-MS: 1240.72.

[0143] Synthesis of compound (33):

[0144] Compound 33-6 (3.1 g, 2.5 mmol), compound 33-7 (1.0 g, 5.2 mmol), and piperidine (5.0 mL) were added sequentially to a 250 mL three-necked flask. 100 mL of chloroform was added, and the mixture was purged with argon three times. The temperature was then raised to 60 °C and reacted for 12 h. After cooling to room temperature, excess solvent was removed by vacuum distillation. The crude product was washed with 100 mL of methanol, filtered, and the filter cake was dissolved in dichloromethane and then subjected to silica gel chromatography with a PE:DCM ratio of 10:1 (volume ratio). Approximately 2.7 g of compound (33) was obtained, yield: 66.9%, MALDI-TOF-MS: 1605.21.

[0145] Application Example 1: Fabrication and Characterization of Organic Solar Cell Devices

[0146] Using the compound prepared in the above embodiments as the acceptor material for the photoactive layer, an organic solar cell device was fabricated. The device structure is: ITO / PEDOT:PSS / photoactive layer / PFN-Br / Ag, as shown in the schematic diagram. Figure 1 As shown, the specific steps include:

[0147] 1) ITO substrate cleaning: The transparent conductive glass with striped ITO (anode) etched on the surface is cleaned by ultrasonic oscillation with cleaning agent, deionized water, acetone and isopropanol in sequence, dried, and then treated with oxygen plasma for 15 minutes.

[0148] 2) Preparation of the anode buffer layer: PEDOT:PSS (CLEVIOS) is spin-coated onto the surface of conductive glass. TM PVP AI 4083), dry at 150℃ for 15 minutes at a speed of 3000 r / min for 40 seconds.

[0149] 3) Preparation of photoactive layer: In a glove box (inert gas atmosphere), the photoactive layer material (donor material selected from PM6, acceptor material selected from compound (2) prepared in synthesis example 1, the mass ratio of PM6 to compound (2) is 1:1, the solvent is chloroform, and the total concentration of donor and acceptor materials in chloroform is 16 mg / mL) is uniformly spin-coated onto the anode buffer layer. The spin-coating speed is 3000 rpm / min and the spin-coating time is 40 seconds to obtain the photoactive layer.

[0150] 4) Preparation of cathode buffer layer: After hot annealing on a hot table at 100℃ for 10 min, the cathode buffer layer material PFN-Br (PFN-Br is dissolved in methanol to prepare a solution with a concentration of 0.5 mg / mL) is uniformly spin-coated onto the photoactive layer at a spin speed of 2000 rpm / min for 30 s to obtain the cathode buffer layer.

[0151] 5) Cathode layer preparation: under high vacuum (1×10⁻⁶) -6Ag is deposited onto the cathode buffer layer in millibars to form a cathode layer with a thickness of 100 nm.

[0152] 6) Encapsulation: The device is encapsulated in a nitrogen glove box using UV-cured resin.

[0153] Application Example 2-7

[0154] In Application Example 1, the acceptor material compound (2) in the photoactive layer was replaced with compound (7), compound (10), compound (17), compound (22), compound (31), and compound (33), respectively. The other steps were the same as in Application Example 1. The devices prepared were designated as Application Examples 2 to 7, as detailed in Table 1.

[0155] The organic solar cell device was tested for performance. Under the standard light of AM1.5G from the solar simulator (SS-F5-3A), the current-voltage curve of the cell was tested and the photoelectric conversion efficiency was calculated. The specific values ​​are shown in Table 1.

[0156] Table 1. Photovoltaic conversion efficiency of solar cell devices fabricated in application examples.

[0157] Serial Number Photoactive layer acceptor materials Photoelectric conversion efficiency (%) Application Example 1 Compound (2) 14.71 Application Example 2 Compound (7) 13.25 Application Example 3 Compound (10) 14.26 Application Example 4 Compound (17) 13.80 Application Example 5 Compound (22) 11.39 Application Example 6 Compound (31) 12.67 Application Example 7 Compound (33) 11.10

[0158] As shown in Table 1, the non-fused-ring small molecule material described in this invention, when used as a photoactive layer material in organic solar cell devices, exhibits good photoelectric conversion efficiency. This is because the non-fused-ring small molecule material provided in this invention creatively introduces a side-chain thiophene group into the core group thiophene. The S atom on the side-chain thiophene and the N atom on the main chain thiazole are conformationally locked through an S-N non-covalent bond, effectively restricting the rotation of the C-C single bond. To further achieve molecular order, this invention further introduces alkoxy substitutions into the main chain thiophene, with an S-O non-covalent bond achieving conformational locking between thiophene and thiazole. Therefore, good molecular packing and efficient electron transport are achieved, resulting in high photoelectric conversion efficiency when used as a photoactive layer acceptor material in organic solar cell devices.

[0159] The preferred embodiments of this application have been described in detail above. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, and these simple modifications all fall within the protection scope of this application.

Claims

1. A non-fused-ring small molecule material, characterized in that, It has a structure as shown in general formula (I): in: R1, R2, and R3 are each independently selected from -H, -D, -F, -Cl, -Br, -I, -CN, -CF3, -NO2, straight-chain alkyl with 1-20 carbon atoms, branched alkyl with 3-20 carbon atoms, straight-chain alkoxy with 1-20 carbon atoms, branched alkoxy with 3-20 carbon atoms, straight-chain alkylthio with 1-20 carbon atoms, or branched alkylthio with 3-20 carbon atoms. Each time R4 appears, it is independently selected from straight-chain alkyl groups having 1-20 carbon atoms or branched alkyl groups having 3-20 carbon atoms; Ar1 and Ar2 are independently selected from the following groups: Wherein: n1 appears each time, independently selected from 0, 1, 2, 3 or 4; n2 appears each time, independently selected from 0, 1, 2, 3, 4, 5 or 6; n3 appears each time, independently selected from 0, 1 or 2; * indicates a fusion site, which is selected from C atoms; R * Each occurrence is independently selected from -D, -F, -Cl, -Br, -I, -CN, -CF3, -NO2, straight-chain alkyl with 1-10 carbon atoms, branched-chain alkyl with 3-10 carbon atoms, straight-chain alkoxy with 1-10 carbon atoms, branched-chain alkoxy with 3-10 carbon atoms, straight-chain alkylthio with 1-10 carbon atoms, or branched-chain alkylthio with 3-10 carbon atoms.

2. The non-fused-ring small molecule material according to claim 1, characterized in that, The non-fused-ring small molecule material is selected from any structure of general formula (II-1)-(II-4):

3. The non-fused-ring small molecule material according to claim 1 or 2, characterized in that, The R * Each occurrence is independently selected from -D, -F, -Cl, -Br, -I, -CN, -CF3, -NO2, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, cyclopentyl, cyclohexyl, methoxy, or methylthio.

4. The non-fused-ring small molecule material according to claim 1, characterized in that, Each time R1 appears, it is independently selected from a straight-chain alkyl group having 1-16 carbon atoms, a branched alkyl group having 3-16 carbon atoms, a straight-chain alkoxy group having 1-16 carbon atoms, a branched alkoxy group having 3-16 carbon atoms, a straight-chain alkylthio group having 1-16 carbon atoms, or a branched alkylthio group having 3-16 carbon atoms. And / or, each time R2 and R3 appear, they are independently selected from -H, -D, -F, -Cl, -Br, -I, -CN, -CF3, -NO2, straight-chain alkyl with 1-10 C atoms, and branched alkyl with 3-10 C atoms; And / or, each time R4 appears, it is independently selected from straight-chain alkyl groups having 4-20 carbon atoms, or branched alkyl groups having 4-20 carbon atoms.

5. The non-fused-ring small molecule material according to claim 1 or 2, characterized in that, Each time R1 appears, it is independently selected from straight-chain alkyl groups with 1-10 carbon atoms or branched alkyl groups with 3-10 carbon atoms; Furthermore, R2 and R3 are selected from -H.

6. The non-fused-ring small molecule material according to claim 1, characterized in that, The non-fused-ring small molecule material is selected from the following structures:

7. A mixture comprising a photoactive layer donor material and a photoactive layer acceptor material, characterized in that, The photoactive layer acceptor material is selected from the non-fused-ring small molecule materials described in any one of claims 1-6.

8. A composition, characterized in that: The composition comprises a non-fused-ring small molecule material as described in any one of claims 1-6 or a mixture as described in claim 7, and at least one organic solvent.

9. An organic solar cell device, said organic solar cell device comprising at least a cathode, an anode, and a photoactive layer located between the cathode and the anode, characterized in that, The photoactive layer material comprises the non-fused-ring small molecule material as described in any one of claims 1-6 or the mixture as described in claim 7, or is prepared from the composition as described in claim 8.

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