Anthracene bithiadiazole-based A-D-A '-D-A type fused ring receptor micromolecule material as well as preparation method and application thereof

Abstract

The invention discloses an anthracene bithiadiazole-based A-D-A '-D-A type fused ring receptor micromolecule material as well as a preparation method and application thereof, and belongs to the technical field of organic photoelectric functional materials. The material takes an anthracene [1, 2-c: 5, 6-c '] bis ([1, 2, 5] thiadiazole) (ABT) unit as a central electron-deficient framework, and two sides of the central electron-deficient framework are connected with an electron donating (D) unit and an end group electron withdrawing (A) unit to construct a condensed ring structure with an extended conjugated system; according to the structure, intramolecular charge transfer is enhanced, the absorption spectrum of the material is widened and subjected to red shift, meanwhile, the LUMO energy level of the material is finely regulated and controlled through the steric hindrance effect of a fused ring core, and higher open-circuit voltage can be obtained; besides, the rigid plane structure of the ABT core promotes ordered'face-on 'oriented accumulation of molecules, and optimizes the microstructure of the active layer, thereby improving the charge transfer efficiency and the device stability. The acceptor material disclosed by the invention has important application value in the fields of flexible electronics and high-efficiency photovoltaics.

Description

Technical Field

[0001] This invention relates to the field of organic optoelectronic materials technology, specifically to an AD-A'-DA type non-fullerene acceptor small molecule material with anthracene [1,2-c:5,6-c']bis([1,2,5]thiadiazole) as the core electron-deficient unit (A'), its preparation method, and its application in organic solar cells. Background Technology

[0002] Organic solar cells (OSCs) have become a research hotspot in next-generation photovoltaic technology due to their advantages such as light weight, flexibility, and solution-processability. As a core component of OSC devices, the design and development of the active layer material system is a key technological bottleneck for improving photoelectric conversion efficiency. In recent years, the emergence of non-fullerene acceptor materials has greatly promoted the development of OSCs, leading to continuous breakthroughs in their photoelectric conversion efficiency (PCE). Among them, AD-A'-DA type fused ring electron acceptors, represented by Y6 and L8-BO, have attracted much attention due to their advantages such as tunable energy levels, strong and broad absorption spectra, and good planarity.

[0003] However, the acceptor materials based on benzo[c][1,2,5]thiadiazole (BT) as the core unit currently face bottlenecks in further performance optimization: 1) the broadening and redshift of its absorption spectrum are close to the limit, which limits the further improvement of photocurrent; 2) the energy level modulation flexibility based on BT core is limited, making it difficult to further reduce energy loss while obtaining high short-circuit current; 3) the long-term photothermal stability of the device still needs to be improved, which is closely related to the thermodynamic stability of the microstructure of the active layer.

[0004] Anthracene is an inexpensive, readily available aromatic unit with good planarity and a large conjugated system. Introducing it into the core structure of a non-fullerene acceptor can enhance intermolecular π-π stacking, promote ordered molecular stacking, optimize the microstructure of the active layer, and thus improve charge transport performance. Furthermore, the thiadiazole unit is a strong electron-withdrawing group, which can effectively lower the LUMO energy level of the material, broaden spectral absorption, and increase the open-circuit voltage. Therefore, developing a novel AD-A'-DA type non-fullerene acceptor material based on the fusion of anthracene and thiadiazole is of great significance for simultaneously improving the photoelectric conversion efficiency and stability of devices. Summary of the Invention

[0005] To address the problems mentioned in the background art, this invention provides a novel AD-A'-DA type fused-ring acceptor small molecule material based on anthracene [1,2-c:5,6-c']bis([1,2,5]thiadiazole) with a larger conjugated plane and stronger electron-withdrawing ability, as well as its efficient and reliable synthesis and preparation method, and the application of this acceptor material as an active layer in the preparation of high-performance, high-stability organic solar cells.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The present invention provides a fused-ring acceptor small molecule material based on anthraquinone bis(1,2-c:5,6-c')thiadiazole, the molecule of which has an AD-A'-DA type structure, wherein the A' unit is anthraquinone [1,2-c:5,6-c']bis([1,2,5]thiadiazole) (hereinafter referred to as ABT). The general structural formula of the fused-ring acceptor small molecule material is as follows:

[0008] ;

[0009] in:

[0010] A' represents the anthracene [1,2-c:5,6-c']bi([1,2,5]thiadiazole) core electron-deficient unit formed by the fusion of anthracene with one thiadiazole at each end:

[0011] .

[0012] R1, whether the same or different, is selected from oxygen-substituted straight-chain alkyl groups (OC). n H 2n+1 Oxygen-substituted branched alkyl OC n H 2n+1 Oligoether groups , Phenyl oligoether groups, where n is a natural number from 1 to 10, and m is a natural number from 1 to 4.

[0013] Preferably, R1 is one or more of the following chemical structural formulas:

[0014] .

[0015] D represents an electron-donating unit formed by the fusion of pyrrole with varying numbers of thiophenes, selected from thiophene[3,2-b]pyrrole and its derivatives with substituents. The number of thiophene extended rings on either side of A' can be the same or different to construct a D-A'-D central core structure with symmetry or asymmetry.

[0016] Preferably, D is one or more of the following chemical structural formulas:

[0017] .

[0018] R2 and R3 are independently selected from the same or different hydrogen and C atoms. n H 2n+1 (n≥1) Straight-chain or branched alkyl, phenyl, substituted phenyl, etc.

[0019] Preferably, R2 and R3 are independently one or more of the following chemical structural formulas:

[0020]

[0021] A is an electron-withdrawing terminal unit, which may be the same or different from: indanedione derivatives, indanedione malononitrile derivatives, and their halogenated (fluorine, chlorine, or other halogen atoms), alkyl or alkoxy substituted derivatives; and terminal units obtained by replacing the benzene ring in the aforementioned indanedione derivatives or indanedione malononitrile derivatives with other aromatic or heteroaromatic rings, wherein the other aromatic or heteroaromatic rings include, but are not limited to, thiophene, pyrrole or indole rings.

[0022] Preferably, A is one or more of the following chemical structural formulas:

[0023] .

[0024] Preferably, the AD-A'-DA type fused-ring receptor small molecule material based on anthracene bisthiadiazole is a compound with the following general structural formula, including a centrosymmetric fused-ring receptor small molecule structure and an asymmetric fused-ring receptor small molecule structure.

[0025]

[0026] The small molecular structures of centrosymmetric fused-ring receptors include:

[0027] .

[0028] The asymmetric fused-ring receptor small molecule structure includes:

[0029]

[0030] This invention also provides a method for preparing the fused-ring acceptor small molecule material as described above, comprising the following steps:

[0031] S1. 1,2,5,6-Tetraaminoanthraquinone was prepared from 2,6-diaminoanthraquinone via amino acetylation protection, 1,5-position nitration, acetylate hydrolysis, and nitro reduction.

[0032] S2. The 1,2,5,6-tetraaminoanthraquinone obtained in step S1 is cyclized, brominated and alkylated to prepare the key intermediate 4,10-dibromo-6,12-disubstituted anthracene [1,2-c:5,6-c']bis([1,2,5]thiadiazole) (ABT-2Br).

[0033] S3. The key intermediate ABT-2Br is coupled with a trialkyltin-substituted electron-donating (D) unit in a Stille coupling reaction under a palladium catalyst to obtain the D-A'-D intermediate;

[0034] S4. The D-A'-D intermediate obtained in step S3 is subjected to a Knoevenagel condensation reaction with an electron-withdrawing terminal (A) unit in the presence of an organic base (such as pyridine or triethylamine) to obtain the fused ring acceptor small molecule material.

[0035] Further, in step S1, the reaction conditions for aminoacetylation protection are as follows: using glacial acetic acid and acetic anhydride as solvents and acylation reagents, and reacting at reflux temperature (approximately 118 °C) in the presence of concentrated sulfuric acid as a catalyst for 2-3 h; the reaction conditions for 1,5-position nitration are as follows: using concentrated sulfuric acid as solvent and potassium nitrate as nitration reagent, and reacting at a low temperature of 0-5 °C for 4-5 h; the reaction conditions for acetic acid hydrolysis are as follows: reacting in an aqueous sulfuric acid solution (e.g., 80% sulfuric acid) at 80-95 °C for 1-2 h; the reaction conditions for nitro reduction are as follows: using sodium sulfide nonahydrate as a reducing agent, and reacting in a boiling water bath (approximately 100 °C) for 1-2 h. The intermediates from each step are purified by filtration, washing, and recrystallization (using solvents such as DMF, DMSO, and acetophenone, respectively).

[0036] In step S2, the cyclization reaction involves reacting 1,2,5,6-tetraaminoanthraquinone in the presence of a dehydrating agent (such as phosphorus pentoxide, phosphorus oxychloride, or a mixture thereof) in an aprotic polar solvent (such as 1,2-dichlorobenzene or nitrobenzene) at 150-200 °C. The dehydration and ring closure are carried out at ℃ to generate anthracene [1,2-c:5,6-c']bis([1,2,5]thiadiazole) core; the bromination reaction is carried out by introducing bromine atoms at the 4 and 10 positions of the core, using N-bromosuccinimide (NBS) as the brominating agent, in chloroform or carbon tetrachloride solvent, at room temperature to reflux temperature; the alkylation reaction is carried out by introducing alkyl side chains (such as n-octyl, 2-ethylhexyl) at the 6 and 12 positions of the bromination product, using the corresponding alkyl bromide or iodide as the alkylating agent, in alkaline conditions (such as potassium carbonate, potassium hydroxide) and polar aprotic solvents (such as DMF, DMSO), at 60-120 ℃.

[0037] In step S3, the molar ratio of the key intermediate ABT-2Br, the trialkyltin-substituted electron-donating D unit, and the palladium catalyst is 1:1.0~2.5:0.01~0.05. The palladium catalyst can be selected from either bis(triphenylphosphine)palladium dichloride (Pd(PPh3)2Cl2) or tetra(triphenylphosphine)palladium (Pd(PPh3)4). The reaction is carried out under inert gas protection in an anhydrous and oxygen-free organic solvent (such as toluene or tetrahydrofuran) at 80-120 °C for 6-24 h.

[0038] In step S4, the molar ratio of the D-A'-D intermediate, the electron-withdrawing terminal A unit, and the organic base is 1:1.0~6.0:3.0~30.0. The electron-withdrawing terminal A unit is a compound containing an active methylene group, such as 1,3-indanone, razotanine, or their derivatives; the organic base is pyridine, triethylamine, or piperidine; the reaction is carried out in an alcohol solvent (such as ethanol or a chloroform-ethanol mixture) at reflux temperature for 4-12 h.

[0039] Furthermore, in step 3, when the molar ratio of the ABT-2Br key intermediate, the trialkyltin-substituted electron-donating D unit, and the palladium catalyst is 1:2.0~2.5:0.01~0.05, a symmetrical D-A'-D intermediate is obtained; when the molar ratio of the ABT-2Br key intermediate, the trialkyltin-substituted electron-donating D unit, and the palladium catalyst is 1:1.0~1.5:0.01~0.05, an asymmetric D-A'-D intermediate is obtained.

[0040] Further, in step S4, when the molar ratio of the D-A'-D intermediate, the electron-withdrawing terminal A unit, and the organic base is 1:2.0~6.0:3.0~10.0, a symmetrical acceptor small molecule is obtained; when the molar ratio of the D-A'-D intermediate, the electron-withdrawing terminal A unit, and the organic base is 1:1.0~1.5:3.0~30.0, an asymmetrical acceptor small molecule is obtained.

[0041] The present invention also provides an application of the fused-ring acceptor small molecule material as described above in organic solar cell devices. The fused-ring acceptor small molecule material based on anthracene [1,2-c:5,6-c']bis([1,2,5]thiadiazole) described above is blended with a polymer donor material to form a bulk heterojunction active layer for the preparation of organic solar cell devices.

[0042] The active layer comprises a polymer donor material and a fused-ring acceptor small molecule material. The polymer donor material is one or more of PM6, D18, PBQ6, or PTQ10. The donor-to-acceptor mass ratio can be adjusted within a wide range (1:0.8 to 1:1.5).

[0043] The present invention also provides an organic solar cell device including the active layer, the device structure of which can adopt a conventional structure: substrate / transparent conductive electrode / hole transport layer / the active layer / electron transport layer / metal electrode, or an inverted structure: substrate / transparent conductive electrode / electron transport layer / the active layer / hole transport layer / metal electrode.

[0044] Using the acceptor material of the present invention, various types of organic solar cell devices can be fabricated, including but not limited to: single-junction cells, semi-transparent cells, sub-cells of tandem cells, and flexible cells.

[0045] Compared with the prior art, the beneficial effects of the present invention are:

[0046] (1) This invention is the first to successfully introduce the extended fused ring system of anthracene [1,2-c:5,6-c']bis([1,2,5]thiadiazole) (ABT) as the A' unit into the AD-A'-DA type receptor backbone, and develop a new type of fused ring receptor small molecule.

[0047] (2) Significantly improved photoelectric performance is expected: a) Better light absorption: The ABT core has a larger π-conjugated plane and stronger electron deficiency than the traditional BT core, which can lead to more significant intramolecular charge transfer efficiency. It is expected to significantly redshift and expand the absorption spectrum of the acceptor film, effectively covering a wider near-infrared region, thereby improving the photocurrent of the device; b) Fine energy level control: The ABT core can more effectively reduce the LUMO energy level of the acceptor. Combined with the synergistic effect of terminal halogens (F, Cl), it can achieve a more ideal energy level match with the wide bandgap donor, minimizing energy loss while ensuring efficient charge separation.

[0048] (3) Improved device stability: a) Enhanced molecular stacking: The rigid large planar structure of the ABT core is conducive to the highly ordered “face-on” orientation of molecules in the thin film, enhancing π-π stacking, thereby improving electron mobility and charge transport efficiency; b) Stable active layer morphology: Stronger intermolecular interactions help to form a phase separation morphology with suitable size and stable interpenetrating network structure in the donor / acceptor blend film. This morphology has better resistance to thermal and light stress, which is expected to significantly improve the operating life and storage stability of organic solar cell devices. Attached Figure Description

[0049] Figure 1 The molecular structure of the fused ring acceptor small molecule material of this invention is shown. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Example 1

[0052] Synthesis of centrosymmetric ABT-1 receptor small molecules

[0053] Step 1: Preparation of ABT core intermediates, the specific synthetic route is shown below:

[0054] .

[0055] In a 500 mL three-necked flask, glacial acetic acid (100 mL), acetic anhydride (100 mL), 2,6-diaminoanthraquinone (1, 50 g, 210 mmol), and 10 drops of concentrated sulfuric acid (approximately 0.5 mL) were added sequentially. The reaction mixture was heated to reflux temperature (approximately 118 °C) and stirred for 2 h. During the reaction, compound 1 did not completely dissolve, but the color of the suspension gradually changed from reddish-brown to yellow. After the reaction was complete, the mixture was cooled to room temperature and then filtered. The filter cake was washed with glacial acetic acid (20 mL × 2). The crude product was purified by recrystallization from DMF and then dried in a vacuum oven to give 66.3 g of brown solid compound 2, with a yield of 98%. 1 H NMR (500 MHz, Chloroform-d) δ 9.46 (s, 1H), 8.16 (d, J = 2.0 Hz, 1H), 8.12 (d, J = 8.2 Hz, 1H), 7.89 (dd, J = 8.4, 2.1 Hz, 1H).

[0056] In a 500 mL three-necked flask, concentrated sulfuric acid (400 g) and potassium nitrate (50 g) were added sequentially. The mixture was cooled to below 0 °C. Under vigorous stirring, finely ground compound 2 (25 g, 78 mmol) was slowly added to the above cold acid mixture, maintaining the reaction temperature at 0–5 °C throughout. After approximately 30 min, the solid completely dissolved, and the solution turned orange-red. The nitration reaction was then continued for 4 h, during which a yellow solid gradually precipitated. After the reaction was completed, the reaction solution was slowly poured into a large amount of ice water under stirring to quench it, and the mixture was collected by filtration. The filter cake was thoroughly washed with ice water until the filtrate was neutral. The crude product was purified by recrystallization from DMSO and then dried in a vacuum oven at 60 °C to obtain 22.5 g of bright yellow lumpy solid compound 3, with a yield of 70%. 1 H NMR (500 MHz, Chloroform-d) δ 9.82 (s, 1H), 8.20 – 8.10 (m, 3H).

[0057] In a 1 L double-necked flask, 80% sulfuric acid (approximately 400 g of concentrated sulfuric acid mixed with 200 mL of deionized water) and compound 3 (40 g, 97 mmol) were added sequentially. The mixture was heated to 95 °C and stirred for 2 h until the hydrolysis was complete. After the reaction was complete, the reaction solution was slowly poured into ice water to dilute it, precipitating a solid, which was then filtered. The filter cake was thoroughly washed with ice water until the filtrate was neutral, finally yielding 30.6 g of dark brown solid compound 4, with a yield of 96%. 1 H NMR (500 MHz, Chloroform-d) δ 8.18 (d, J = 7.7 Hz, 2H), 7.76 (d, J = 7.9 Hz, 2H), 7.21 (s, 3H).

[0058] In a 1 L double-necked flask, compound 4 (25 g, 77 mmol), deionized water (approximately 375 mL), and sodium sulfide nonahydrate (90 g, 375 mmol) were added. The mixture was heated to 100 °C and stirred for 1 h. During the reaction, the color of the suspension gradually changed from dark brown to purplish-black. After the reaction was complete, the reaction solution was cooled to room temperature and filtered. The filter cake was washed several times with hot distilled water until the filtrate was neutral. The crude product was purified by recrystallization from acetophenone, and the residual acetophenone was replaced by washing with a small amount of anhydrous ethanol. The product was then dried under vacuum at 50 °C to give 16.9 g of a deep purple crystalline solid of compound 5, with a yield of 82%. 1 HNMR (500 MHz, Chloroform-d) δ 7.90 (d, J = 8.2 Hz, 2H), 7.42 (d, J = 8.1 Hz,2H), 6.26 (d, J = 8.6 Hz, 2H), 6.13 (d, J = 8.4 Hz, 2H), 4.56 (d, J = 7.3 Hz, 2H), 4.47 (d, J = 7.3 Hz, 2H).

[0059] In a 1 L three-necked round-bottom flask, compound 5 (15 g, 56 mmol), triethylamine (50 mL), and tetrahydrofuran (300 mL) were added. The mixture was cooled to below 0 °C, and thionyl chloride (35 mL) was slowly added dropwise, maintaining the reaction temperature between 0 and 5 °C. After the addition was complete, the mixture was heated to room temperature, and the reaction was stirred for 12 h. After the reaction was complete, the reaction solution was quenched in ice water, and a solid precipitated. The solid was collected by filtration and washed successively with chloroform, dimethyl sulfoxide, and acetone. The crude product was purified by thermal gradient vacuum sublimation (source temperature 270 °C, system pressure approximately 0.1 Pa) to finally obtain 6.4 g of deep red solid of compound 6, with a yield of 35%.1 H NMR (500 MHz, Chloroform-d) δ 8.23 ​​(d, J = 8.4 Hz, 1H), 8.06 (d, J = 8.4 Hz, 1H).

[0060] In a 1 L double-necked round-bottom flask, compound 6 (4 g, 12 mmol), KOH (2.72 g, 48 mmol), and DMF (400 mL) were added to form a suspension. The mixture was stirred at room temperature for 10 min, and then 1-bromohexane (12 mL, 48 mmol) was added. The mixture was then heated to 100 °C and stirred for 48 h. After the reaction was complete, the mixture was cooled to room temperature and extracted with chloroform (100 mL × 3). The organic phase was collected, dried over anhydrous sodium sulfate, filtered, and the solvent was removed using a rotary evaporator. The crude product was initially purified by silica gel short-column chromatography using dichloromethane as the eluent. The collected preliminarily purified product was further purified by recrystallization from ethyl acetate to give 4.20 g of orange solid, compound 7, in a yield of 69%. 1 H NMR (500 MHz, Chloroform-d) δ 8.21 (d, J = 8.6 Hz, 1H), 8.06 (d, J =8.6 Hz, 1H), 4.05 (t, J = 6.0 Hz, 2H), 1.79 (tt, J = 7.0, 6.0 Hz, 2H), 1.49 –1.41 (m, 2H), 1.38 – 1.26 (m, 4H), 0.93 – 0.84 (m, 3H).

[0061] Step 2: Introduce D-donor electron units to construct a centrosymmetric D-A'-D fused ring core:

[0062]

[0063]

[0064] In a 1 L dry Schlenk tube, compound 7 (3 g, 6 mmol), FeCl3 (0.97 g, 6 mmol), and glacial acetic acid (400 mL) were added sequentially. Liquid bromine (3.12 mL, 60 mmol) was slowly added dropwise to the suspension while stirring vigorously. The mixture was then heated to 100 °C and the reaction was continued with stirring for 48 h. After the reaction was complete, the reaction mixture was cooled to room temperature and quenched by pouring it into ice water, precipitating a solid, which was collected by filtration. The filter cake was thoroughly washed with methanol (100 mL × 3) until the filtrate was colorless. The crude product was dried under vacuum to give 2.7 g of a dark red solid of compound 8, with a yield of approximately 69%. 1 H NMR(500 MHz, Chloroform-d) δ 8.25 (s, 1H), 4.05 (t, J = 6.0 Hz, 2H), 1.79 (tt, J= 7.0, 6.0 Hz, 2H), 1.49 – 1.41 (m, 2H), 1.38 – 1.26 (m, 4H), 0.93 – 0.84 (m,3H).

[0065] Compound 8 (2.7 g, 4.1 mmol) obtained in the previous step was dissolved in 30 mL of trifluoromethanesulfonic acid and cooled to 0 °C. Concentrated nitric acid (20 mL) was slowly added dropwise to the solution with vigorous stirring, maintaining the temperature between 0 and 5 °C. The mixture was then heated to 50 °C and stirred overnight (approximately 12 h). After the reaction was complete, the reaction solution was cooled to room temperature and quenched in ice water. A 10% sodium hydroxide aqueous solution was then added dropwise until the solution was neutral, precipitating a solid, which was collected by filtration. The filter cake was thoroughly washed with ice water until the filtrate was neutral. The crude product was purified by recrystallization from ethanol to give 2.2 g of a yellow solid, compound 9, in 70% yield. 1 H NMR (500 MHz, Chloroform-d) δ 4.03 (t, J = 6.1 Hz, 2H), 1.79 (tt, J = 7.2, 6.1 Hz, 2H), 1.46 (dt, J = 7.6, 6.7 Hz, 2H), 1.38 – 1.26(m, 4H), 0.93 – 0.84 (m, 3H).

[0066] D-donating electron units were introduced via a Migita-Kosugi-Stille coupling reaction. Compound 9 (1.55 g, 20 mmol), (6-undecylthieno[3,2-b]thiophene-2-yl)tributyltinane (25.7 g, 44 mmol), Pd(PPh3)2Cl2 (0.62 g, 0.88 mmol), and dry toluene (100 mL) were added sequentially to a 250 mL dry Schlenk tube. The mixture was heated to 80 °C under N2 protection and stirred overnight (approximately 12 h). After the reaction was complete, the reaction mixture was cooled to room temperature, and the solvent was removed using a rotary evaporator. The resulting crude product was purified by silica gel column chromatography using dichloromethane / petroleum ether (1:3, v / v) as the eluent, ultimately yielding 15.6 g of compound 10 as a red solid, in 65% yield. 1 H NMR (500 MHz, Chloroform-d) δ 4.03 (t, J = 6.1 Hz, 1H), 2.69 (t, J = 7.5 Hz, 1H), 1.83 –1.75 (m, 1H), 1.59 (p, J = 7.4 Hz, 1H), 1.50 – 1.41 (m, 1H), 1.39 – 1.29 (m,4H), 1.32 – 1.24 (m, 6H), 0.92 – 0.86 (m, 3H).

[0067] Under N2 protection, compound 10 (12.02 g, 10 mmol) and triethyl phosphite (50 mL) were dissolved in anhydrous o-dichlorobenzene (20 mL). The mixture was heated to 180 °C and stirred overnight (approximately 12 h). After the reaction was complete, the reaction solution was cooled to room temperature and extracted with dichloromethane (50 mL × 3). The organic phase was collected, dried over anhydrous sodium sulfate, filtered, and the solvent was removed using a rotary evaporator. Subsequently, the crude product was transferred to another 250 mL dry three-necked round-bottom flask, and 1-bromo-2-ethylhexane (4.83 g, 25 mmol), potassium iodide (0.17 g, 1 mmol), potassium carbonate (4.15 g, 30 mmol), and DMF (80 mL) were added sequentially. After deoxygenation by bubbling with N2 for 15 min, the mixture was heated to 80 °C and refluxed, and stirred for 15 h. After the reaction was complete, the mixture was filtered while hot. The filtrate was concentrated and extracted with ethyl acetate (100 mL × 3). The organic phase was collected, dried over anhydrous sodium sulfate, filtered, and the solvent was removed using a rotary evaporator. The crude product was purified by silica gel column chromatography with dichloromethane / petroleum ether (1:10, v / v) as the eluent, finally yielding 5.99 g of compound 11 as a red solid, in 45% yield. 1 H NMR (500 MHz, Chloroform-d) δ 7.19 (s, 1H), 4.40 (dd, J = 13.4, 5.9 Hz, 1H), 4.30 (dd, J = 13.3, 5.8 Hz, 1H), 4.03 (td, J =6.1, 1.9 Hz, 2H), 2.71 (t, J = 7.5 Hz, 2H), 1.94 (tt, J = 7.1, 6.0 Hz, 1H), 1.79 (tt, J = 7.1, 6.1 Hz, 2H), 1.62 – 1.54 (m, 2H), 1.50 – 1.37 (m, 4H),1.40 – 1.32 (m, 3H), 1.35 – 1.29 (m, 11H), 1.30 (s, 2H), 1.32 – 1.24 (m, 14H), 0.94 – 0.85 (m, 13H).

[0068] Step 3: Connect the terminal A electron-withdrawing unit to synthesize the target centrosymmetric ABT-1 acceptor small molecule:

[0069]

[0070] Compound 11 (5 g, 4 mmol) was dissolved in 200 mL of redistilled THF and cooled to -78 °C under N2 protection. A hexane solution of n-butyllithium (7.5 mL, 1.6 mol / L) was slowly added dropwise with vigorous stirring for 2 h. The mixture was then gradually heated to 0 °C and stirred for 30 min, followed by cooling to -78 °C and the addition of 1.2 mL of anhydrous DMF in a single batch. The mixture was gradually heated to room temperature and stirred overnight (approximately 12 h). After the reaction was complete, the reaction mixture was slowly quenched in ice water and extracted with dichloromethane (100 mL × 3). The organic phase was collected, dried over anhydrous sodium sulfate, and the solvent was removed using a rotary evaporator. The crude product was purified by silica gel column chromatography using dichloromethane / petroleum ether (1:1, v / v) as the eluent to give 3.5 g of compound 12 as a red solid, in 66% yield. 1 H NMR (500MHz, Chloroform-d) δ 9.90 (s, 1H), 4.40 (dd, J = 13.4, 5.9 Hz, 1H), 4.30 (dd,J = 13.3, 5.8 Hz, 1H), 4.03 (td, J = 6.1, 1.9 Hz, 2H), 2.93 (td, J = 7.7, 2.4Hz, 2H), 1.94 (tt, J = 7.1, 6.0 Hz, 1H), 1.79 (tt, J = 7.1, 6.1 Hz, 2H), 1.63– 1.55 (m, 2H), 1.50 – 1.40 (m, 3H), 1.42 – 1.37 (m, 1H), 1.40 – 1.34 (m,2H), 1.37 – 1.26 (m, 17H), 1.27 (d, J = 3.2 Hz, 8H), 0.94 – 0.86 (m, 12H).

[0071] Under N2 protection, compound 12 (1 g, 0.7 mmol), 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-yl)malononitrile (0.97 g, 4.2 mmol), pyridine (0.2 mL), and anhydrous chloroform (50 mL) were sequentially added to a dry 250 mL round-bottom flask. The mixture was heated to 65 °C and stirred overnight (approximately 12 h). After the reaction was complete, the reaction solution was cooled to room temperature and slowly poured into methanol to precipitate a solid, which was collected by filtration. The crude product was purified by silica gel column chromatography using dichloromethane / petroleum ether (1:1, v / v) as the eluent to give 0.81 g of a deep blue solid (ABT-1), with a yield of 64%. 1 H NMR (500 MHz, Chloroform-d) δ 8.08 (d, J = 12.0 Hz, 1H), 8.03 (s, 1H), 4.40 (dd, J = 13.4, 5.9 Hz, 1H), 4.30 (dd, J = 13.3, 5.8 Hz, 1H), 4.03 (td, J = 6.1, 1.9 Hz, 2H), 3.02 – 2.86 (m, 2H), 1.94 (tt, J = 7.1, 5.9 Hz, 1H), 1.79 (tt, J = 7.1, 6.1 Hz, 2H), 1.65 – 1.53 (m, 2H), 1.49 – 1.42 (m, 2H), 1.45 –1.38 (m, 1H), 1.41 – 1.34 (m, 2H), 1.36 (d, J = 2.1 Hz, 1H), 1.37 – 1.31 (m,3H), 1.33 (s, 1H), 1.34 – 1.26 (m, 15H), 1.27 (s, 1H), 1.27 (s, 4H), 0.94 –0.85 (m, 12H).

[0072] Example 2

[0073] Synthesis of asymmetric ABT-7 receptor small molecules

[0074] Using the centrosymmetric D-A'-D fused-ring core intermediate constructed in Example 1, small molecules based on ABT asymmetric fused-ring acceptors containing different end-group A units were synthesized by controlling the temperature, A unit feed ratio, and reaction time during the Knoevenagel condensation reaction.

[0075] Step 1: Connecting electron-withdrawing units with different terminal groups to synthesize the target asymmetric ABT-7 acceptor small molecule:

[0076]

[0077] Under N2 protection, compound 12 (2 g, 1.4 mmol) and 2-(5,6-dichloro-3-oxo-2,3-dihydro-1H-inden-1-yl)malononitrile (0.5 g, 1.7 mmol) were dissolved in anhydrous chloroform (100 mL), followed by the addition of anhydrous pyridine (0.5 mL). The mixture was heated to 50 °C and stirred for 8 h. After the reaction was complete, the reaction solution was cooled to room temperature and slowly poured into methanol to precipitate a solid, which was collected by filtration. The crude product was purified by silica gel column chromatography using petroleum ether / chloroform (1:1, v / v) as eluent to give 1.5 g of dark blue solid 13, in 64% yield. 1 H NMR (500 MHz, Chloroform-d) δ 8.15 (d, J = 13.8 Hz, 1H), 4.40 (dd, J = 13.2, 5.8 Hz, 1H), 4.30 (dd, J = 13.3, 5.8 Hz, 1H), 4.03 (td, J = 6.0, 1.8 Hz, 2H), 3.02 – 2.86(m, 2H), 1.94 (tp, J = 7.2, 5.9 Hz, 1H), 1.83 – 1.75 (m, 2H), 1.64 – 1.55 (m,2H), 1.50 – 1.39 (m, 3H), 1.42 – 1.36 (m, 1H), 1.39 – 1.31 (m, 6H), 1.34 –1.29 (m, 6H), 1.31 – 1.24 (m, 12H), 0.95 – 0.86 (m, 12H).

[0078] Under nitrogen protection, compound 13 (1 g, 0.61 mmol) and 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-yl)malononitrile (0.20 g, 0.87 mmol) were dissolved in anhydrous chloroform (50 mL), followed by the addition of anhydrous pyridine (0.2 mL). The reaction mixture was heated to reflux (65 °C) and stirred overnight (approximately 12 h). After the reaction was complete, the reaction solution was cooled to room temperature and slowly poured into methanol to precipitate a solid, which was collected by filtration. The crude product was purified by silica gel column chromatography using petroleum ether / chloroform (1:2, v / v) as the eluent, ultimately yielding 1.02 g of a dark blue to black solid (ABT-7), in 90% yield. 1H NMR (500 MHz, Chloroform-d) δ 4.40 (dd, J = 13.2, 5.8 Hz, 0H), 4.30 (dd, J = 13.3, 5.8 Hz, 0H), 4.03 (td, J = 6.0, 1.8 Hz, 1H), 3.02 –2.86 (m, 1H), 1.94 (tt, J = 7.2, 6.0 Hz, 0H), 1.83 – 1.75 (m, 1H), 1.65 –1.53 (m, 1H), 1.49 – 1.24 (m, 14H), 0.94 – 0.84 (m, 6H).

[0079] Example 3

[0080] Synthesis of asymmetric [2+3]ABT-15 receptor small molecules

[0081] Using the ABT core intermediate prepared in Example 1, an asymmetric [n+m]D-A'-D fused ring core (where n and m represent the number of thiophene extended rings on both sides of A', and n ≠ m) was constructed by controlling the catalyst system, the tin reagent feed ratio, and the reaction time during the Stille coupling reaction, thus realizing the synthesis of a small molecule based on the [n+m]ABT asymmetric fused ring acceptor.

[0082] Step 1: Introduce different D-donating electron units to construct an asymmetric [2+3]D-A'-D fused ring core:

[0083]

[0084] Under N2 protection, compound 9 (1.54 g, 2.00 mmol), (6-undecylthieno[3,2-b]thiophene-2-yl)tributyltinane (1.17 g, 2 mmol), Pd2(dba)3 (18 mg, 0.02 mmol), P(o-tolyl)3 (24 mg, 0.08 mmol), and anhydrous toluene (10 mL) were added sequentially to a dry 100 mL round-bottom flask. The mixture was heated to 110 °C and refluxed, and the reaction was stirred for 12 h. After the reaction was complete, the reaction solution was cooled to room temperature, and the solvent was removed using a rotary evaporator. The crude product was purified by silica gel column chromatography using n-hexane / dichloromethane (5:1, v / v) as the eluent to give compound 14 as 0.89 g of red solid, in 45% yield. 1H NMR (500 MHz, Chloroform-d) δ 4.03(td, J = 6.1, 1.0 Hz, 2H), 2.69 (t, J = 7.5 Hz, 1H), 1.79 (tt, J = 7.1, 6.1Hz, 2H), 1.59 (p, J = 7.5 Hz, 1H), 1.49 – 1.41 (m, 2H), 1.39 – 1.24 (m, 13H), 0.93 – 0.84 (m, 5H).

[0085] Under N2 protection, compound 14 (800 mg, 0.81 mmol), (5-undecyldithieno[3,2-b:2',3'-d]thiophene-2-yl)tributyltinane (621 mg, 0.97 mmol), Pd2(dba)3 (27 mg, 0.03 mmol), P(o-tolyl)3 (37 mg, 0.12 mmol), and anhydrous toluene (10 mL) were added sequentially to a dry 100 mL round-bottom flask. The mixture was heated to 110 °C and refluxed, and the reaction was stirred for 12 h. After the reaction was completed, the reaction solution was cooled to room temperature, and the solvent was removed using a rotary evaporator. The crude product was purified by silica gel column chromatography using n-hexane / dichloromethane (4:1, v / v) as the eluent to give compound 15 as 937 mg of red solid, in 92% yield. 1 H NMR (500 MHz, Chloroform-d) δ 4.03 (t, J = 6.1 Hz, 1H), 2.70 (q, J = 7.4 Hz, 1H), 1.83 –1.75 (m, 1H), 1.59 (p, J = 7.4 Hz, 1H), 1.50 – 1.41 (m, 1H), 1.39 – 1.30 (m,4H), 1.32 – 1.27 (m, 1H), 1.30 – 1.24 (m, 5H), 0.93 – 0.85 (m, 3H).

[0086] Under nitrogen protection, compound 15 (900 mg, 0.72 mmol), triethyl phosphite (1 mL), and anhydrous o-dichlorobenzene (15 mL) were added sequentially to a dry 50 mL round-bottom flask. The mixture was heated to 185 °C and stirred for 12 h. After the reaction was complete, the reaction solution was cooled to room temperature, and the solvent was removed using a rotary evaporator to obtain the crude product. Subsequently, the crude product obtained in the previous step was transferred to another dry 50 mL round-bottom flask, and 1-bromo-2-ethylhexane (0.35 g, 1.8 mmol), potassium iodide (12 mg, 0.07 mmol), potassium carbonate (304 mg, 2.2 mmol), and DMF (10 mL) were added sequentially. The mixture was heated to 80 °C and stirred for another 12 h. After the reaction was complete, the reaction solution was cooled to room temperature and extracted with dichloromethane. The organic phase was collected, dried over anhydrous sodium sulfate, and the solvent was removed using a rotary evaporator. The crude product was purified by silica gel column chromatography using n-hexane / dichloromethane (6:1, v / v) as eluent to give 579 mg of red solid compound 16, with a yield of 58%. 1 H NMR (500 MHz, Chloroform-d) δ 4.40 (dd, J = 13.2, 5.8 Hz, 1H), 4.30 (dd, J = 13.3, 5.8 Hz, 1H), 4.03 (td, J = 6.0, 1.8 Hz, 2H), 2.75 –2.66 (m, 2H), 1.94 (tt, J = 7.2, 6.0 Hz, 1H), 1.83 – 1.75 (m, 2H), 1.64 –1.54 (m, 2H), 1.49 – 1.44 (m, 1H), 1.47 – 1.38 (m, 2H), 1.41 – 1.34 (m, 1H),1.38 – 1.31 (m, 7H), 1.32 (q, J = 1.5 Hz, 3H), 1.33 – 1.28 (m, 4H), 1.30 –1.24 (m, 11H), 0.94 – 0.84 (m, 12H).

[0087] Step 2: Connect the terminal A electron-withdrawing unit to synthesize the target asymmetric [2+3]ABT-15 acceptor small molecule:

[0088]

[0089] Under nitrogen protection, 5 mL of anhydrous DMF was added to a dry 50 mL double-necked round-bottom flask, and the solution was cooled to 0 °C. Phosphorus oxychloride (1 mL) was slowly added dropwise to the solution with vigorous stirring. After the addition was complete, the mixture was stirred at 0 °C for 1 h to form Vilsmeier's reagent in situ. Subsequently, compound 16 (500 mg, 0.36 mmol) was dissolved in anhydrous 1,2-dichloroethane (10 mL), and this solution was slowly added to the reaction system. After the addition was complete, the mixture was heated to 80 °C and refluxed with stirring overnight (approximately 12 h). After the reaction was complete, the reaction solution was cooled to room temperature and then slowly quenched in ice water. The solution was then extracted with dichloromethane, the organic phase was collected, and the solvent was removed using a rotary evaporator. The crude product was purified by silica gel column chromatography with hexane / dichloromethane (1:1, v / v) as eluent to give compound 17 as 441 mg of red solid, with a yield of 85%. 1 H NMR (500 MHz, Chloroform-d) δ 9.91 (d, J= 8.6 Hz, 1H), 4.40 (dd, J = 13.2, 5.8 Hz, 1H), 4.30 (dd, J = 13.3, 5.8 Hz,1H), 4.03 (td, J = 6.0, 1.8 Hz, 2H), 2.98 – 2.88 (m, 2H), 1.94 (tp, J = 7.2,5.9 Hz, 1H), 1.83 – 1.75 (m, 2H), 1.63 – 1.55 (m, 2H), 1.50 – 1.40 (m, 3H),1.43 – 1.37 (m, 1H), 1.37 (ddd, J = 7.0, 5.5, 4.0 Hz, 3H), 1.36 – 1.27 (m,11H), 1.31 – 1.24 (m, 10H), 0.94 – 0.84 (m, 12H).

[0090] Under N2 protection, compound 17 (400 mg, 0.28 mmol), 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-yl)malononitrile (258 mg, 1.12 mmol), and anhydrous chloroform (30 mL) were added to a dry 100 mL round-bottom flask. After deoxygenation by bubbling with N2 for 10 min, pyridine (0.5 mL) was added to the reaction system with stirring. The mixture was heated to 70 °C and refluxed, and the reaction was stirred for 12 h. After the reaction was completed, the reaction solution was cooled to room temperature, poured into methanol, stirred to precipitate a solid, and collected by filtration. The crude product was purified by silica gel column chromatography using n-hexane / dichloromethane (1:1, v / v) as eluent, finally yielding 460 mg of a dark blue to black solid ([2+3]ABT-15), with a yield of 88%. 1 H NMR (500MHz, Chloroform-d) δ 8.08 (d, J = 11.9 Hz, 1H), 8.03 (d, J = 2.0 Hz, 1H), 4.40 (dd, J = 13.2, 5.8 Hz, 1H), 4.30 (dd, J = 13.3, 5.8 Hz, 1H), 4.03 (td, J= 6.0, 1.8 Hz, 2H), 3.02 – 2.86 (m, 2H), 1.94 (tt, J = 7.2, 6.0 Hz, 1H), 1.83– 1.75 (m, 2H), 1.65 – 1.53 (m, 2H), 1.49 – 1.42 (m, 2H), 1.45 – 1.39 (m,1H), 1.42 – 1.35 (m, 3H), 1.37 – 1.32 (m, 2H), 1.35 – 1.29 (m, 8H), 1.32 –1.24 (m, 12H), 0.94 – 0.84 (m, 12H).

[0091] Example 4

[0092] Fabrication and performance testing of organic solar cell devices

[0093] (1) Fabrication of conventional structure devices: ITO / PEDOT:PSS / active layer / electron transport layer / metal electrode

[0094] Commercially available ITO conductive glass substrates, comprising a glass substrate and an indium tin oxide conductive layer formed thereon, wherein the sheet resistance of the conductive layer is 10-20 Ω / sq, are ultrasonically cleaned sequentially with detergent, deionized water, acetone and isopropanol, then dried and subjected to ultraviolet ozone treatment for 120 s.

[0095] A hole transport material solution is spin-coated onto the ITO substrate to form a hole transport layer, followed by thermal annealing. Preferably, the hole transport material is poly(3,4-ethylenedioxythiophene)polystyrene sulfonate (PEDOT:PSS); the spin-coating speed is 2000-5000 rpm / min, and in this embodiment, the spin-coating speed is 4000 rpm / min; the annealing temperature is 120-180 ℃, and in this embodiment, the annealing temperature is 150 ℃; the annealing time is 10-30 min, and in this embodiment, the annealing time is 20 min.

[0096] The polymer donor material and the anthracene-bisthiadiazole-based AD-A'-DA type fused-ring acceptor small molecule material (in this embodiment, the acceptor small molecule is ABT-1, ABT-7, or [2+3]ABT-15 synthesized in Examples 1-3) were dissolved in an organic solvent, and an additive of a certain volume ratio was added to prepare an active layer blend solution. The blend solution was spin-coated onto the hole transport layer to form an active layer film, followed by thermal annealing.

[0097] The polymer donor material is selected from at least one of PM6, D18, PBQ6 or PTQ10; in this embodiment, the polymer donor material is PM6.

[0098] The donor-to-receptor mass ratio is from 1:0.8 to 1:1.5, and in this embodiment, the donor-to-receptor mass ratio is 1:1.2.

[0099] The organic solvents include chloroform, chlorobenzene, o-xylene, etc., and the organic solvent in this embodiment is chlorobenzene;

[0100] The additive is 1,8-diiodooctane, 1-chloronaphthalene, etc., and its volume percentage is 0.2%-2% of the organic solvent; in this embodiment, the additive is 1-chloronaphthalene, and its volume percentage is 0.5% of the organic solvent;

[0101] The total concentration of the active layer (i.e., the blend system of the polymer donor and the small molecule acceptor of the present invention) is 10-20 mg / mL, and the total concentration of the active layer in this embodiment is 16 mg / mL;

[0102] The spin coating speed is 2000-4000 rpm / min, and in this embodiment, the spin coating speed is 3000 rpm / min to obtain an active layer with a thickness of 100-150 nm; the annealing temperature is 80-120 ℃, and in this embodiment, the annealing temperature is 100 ℃, and the time is 5-15 min.

[0103] An electron transport material solution is spin-coated onto the active layer to form an electron transport layer. Preferably, the electron transport material is PNDIT-F3N-Br, the solvent is trifluoroethanol, and the concentration is 0.2-1.0 mg / mL.

[0104] Under vacuum conditions, a metal electrode is deposited on the electron transport layer to complete the device fabrication. The metal electrode is silver, aluminum, or gold; in this embodiment, it is silver. The thickness is 80-200 nm; in this embodiment, it is 150 nm. The vacuum level is no higher than 5 × 10⁻⁶. -4 Pa, the vacuum degree in this embodiment is 1 × 10⁻⁶. -4 Pa.

[0105] Organic solar cell devices prepared by the above method have advantages such as simple structure, excellent performance, and solution-processability, and are suitable for single-junction, flexible or semi-transparent photovoltaic devices.

[0106] (2) Fabrication of inverted structure devices: ITO / electron transport layer / active layer / hole transport layer / metal electrode

[0107] A ZnO precursor solution was prepared and spin-coated onto a cleaned and pretreated ITO glass substrate, followed by annealing to form an electron transport layer. The ZnO precursor solution contained a zinc salt and an alkanolamine ligand, obtained by reacting them in an alkoxyethanol solvent. In this embodiment, the zinc salt used in the ZnO precursor solution was zinc acetate, the ligand was ethanolamine, and the solvent was 2-methoxyethanol. The spin-coating speed was 2000-4000 rpm / min, and in this embodiment, the spin-coating speed was 3000 rpm / min. The annealing temperature was 130-170 °C, and in this embodiment, the annealing temperature was 150 °C. The annealing time was 10-20 min, and in this embodiment, the annealing time was 20 min.

[0108] A polymer donor material selected from at least one of PM6, D18, PBQ6, or PTQ10 is blended with an anthracene-bisthiadiazole-based AD-A'-DA type fused-ring acceptor small molecule material as described above (in this embodiment, the acceptor small molecule is ABT-1, ABT-7, or [2+3]ABT-15 synthesized in Examples 1-3), dissolved in an organic solvent, and with the addition of additives, to prepare an active layer blending solvent. This solution is spin-coated onto the electron transport layer and subjected to thermal annealing to form the active layer. In this embodiment, the polymer donor material is PM6; the mass ratio of the donor to the acceptor is 1:0.8 to 1:1.5, and in this embodiment, the mass ratio is 1:1.2; the organic solvent includes chloroform, chlorobenzene, o-xylene, etc., and in this embodiment, the organic solvent is chlorobenzene; the additives are 1,8-diiodooctane, 1-chloronaphthalene, etc., and their volume percentage is 0.2%-2% of the organic solvent, and in this embodiment, the additive is 1-chloronaphthalene, and its volume percentage is 0.5% of the organic solvent; the total concentration of the active layer is 10-20 mg / mL, and in this embodiment, the total concentration of the active layer is 16 mg / mL; the spin coating speed is 2000-4000 rpm / min, and in this embodiment, the spin coating speed is 3000 rpm / min; the annealing temperature is 80-120 ℃, and in this embodiment, the annealing temperature is 100 ℃; the annealing time is 5-15 min, and in this embodiment, the time is 10 min; the active layer thickness is 100-150 nm, and in this embodiment, the active layer thickness is 100 nm. nm.

[0109] A hole transport material layer and a metal electrode layer are sequentially vacuum-deposited onto the active layer. The hole transport material is MoO3, V2O5, etc., with a thickness of 3-10 nm; in this embodiment, MoO3 is used with a thickness of 10 nm. The metal electrode is silver, aluminum, or gold, with a thickness of 80-150 nm; in this embodiment, silver is used with a thickness of 100 nm. The vacuum degree is no higher than 5 × 10⁻⁶. -4 Pa, the vacuum degree in this embodiment is 1 × 10⁻⁶. -4 Pa.

[0110] The inverted organic solar cell device prepared by the above method exhibits high interface stability, applicability to flexible substrates, and extended device lifetime. Furthermore, in device performance testing, a light-shielding mask with a defined aperture size can be placed on the device surface to reduce edge effects caused by light guide and internal scattering, thereby obtaining the short-circuit current density (J / L) more accurately. sc ) and other parameters.

[0111] (3) Performance testing: a) Under standard test conditions (AM 1.5G spectrum, illuminance 100 mW cm⁻¹) -2Under these conditions, the current density-voltage (JV) characteristic curve of the device is tested using a solar simulator and a source measurement unit, thereby obtaining the open-circuit voltage (V). oc ), short-circuit current density (J sc Key parameters include: b) fill factor (FF) and power conversion efficiency (PCE); c) external quantum efficiency (EQE) testing system is used to measure the spectral response of the device in the wavelength range of 300-950 nm to characterize its broad-spectrum absorption capability, especially its response characteristics in the near-infrared region of 800-900 nm; d) unpackaged devices are placed in a glove box under N2 atmosphere and continuously aged on a hot stage at 85 ℃. The thermal stability of the device is evaluated by periodically measuring its performance degradation. For example, the test target could be that the device maintains an initial power conversion efficiency of over 90% (i.e., T0) after 1000 h of aging. 90 > 1000h).

[0112] Table 1. Device performance parameters of organic solar cells in the examples.

[0113]

[0114] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0115] It should be noted that the above content merely illustrates the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, various improvements and modifications can be made without departing from the principle of the present invention, and all such improvements and modifications fall within the scope of protection of the claims of the present invention.

Claims

1. A small molecule material of AD-A'-DA type fused-ring acceptor based on anthracene bisthiadiazole, characterized in that, It has the following structure: ； Wherein, R1 is the same or different and is selected from oxygen-substituted straight-chain alkyl groups (OC). n H 2n+1 Oxygen-substituted branched alkyl OC n H 2n+1 Oligoether groups , Phenyl oligoether groups, where n is a natural number from 1 to 10, and m is a natural number from 1 to 4; D, whether the same or different, is selected from thiophene[3,2-b]pyrrole and its derivatives with substituents; A is an electron-withdrawing terminal unit, which may be the same or different from: ninhydrin derivatives, ninhydrin malononitrile derivatives, halogenated, alkylated or alkoxylated derivatives of ninhydrin derivatives or ninhydrin malononitrile derivatives, or terminal units obtained by replacing the benzene ring in ninhydrin derivatives or ninhydrin malononitrile derivatives with other aromatic or heteroaromatic rings.

2. The small molecule material of AD-A'-DA type fused-ring acceptor based on anthracene bisthiadiazole according to claim 1, characterized in that, R1 is one or more of the following chemical structural formulas: 。 3. The small molecule material of AD-A'-DA type fused ring acceptor based on anthracene bisthiadiazole according to claim 1, characterized in that, D is one or more of the following chemical structural formulas: ； Wherein, R2 and R3 are hydrogen and C, respectively. n H 2n+1 Straight chain, C n H 2n+1 One or more of branched alkyl, phenyl, and substituted phenyl groups, where n ≥ 1.

4. The small molecule material of AD-A'-DA type fused ring acceptor based on anthracene bisthiadiazole according to claim 3, characterized in that, R2 and R3 can each independently be one or more of the following chemical structural formulas: 。 5. The small molecule material of AD-A'-DA type fused ring acceptor based on anthracene bisthiadiazole according to claim 1, characterized in that, A can be one or more of the following chemical structural formulas: 。 6. A method for preparing an AD-A'-DA type fused-ring acceptor small molecule material based on anthracene bisthiadiazole according to any one of claims 1-5, characterized in that, Includes the following steps: S1. 1,2,5,6-Tetraaminoanthraquinone was prepared from 2,6-diaminoanthraquinone via amino acetylation protection, 1,5-position nitration, acetylate hydrolysis, and nitro reduction. S2. The 1,2,5,6-tetraaminoanthraquinone obtained in step S1 is cyclized, brominated and alkylated to prepare 4,10-dibromo-6,12-disubstituted anthracene[1,2-c:5,6-c']bis([1,2,5]thiadiazole), which is the key intermediate of ABT-2Br. S3. The key intermediate ABT-2Br is coupled with a trialkyltin-substituted electron-donating (D) unit in a palladium catalyst via a Stille coupling reaction to obtain a symmetrical or asymmetrical D-A'-D intermediate. S4. The D-A'-D intermediate obtained in step S3 is subjected to a Knoevenagel condensation reaction with an electron-withdrawing terminal (A) unit in the presence of an organic base (such as pyridine or triethylamine) to obtain the symmetrical or asymmetric fused ring acceptor small molecule material.

7. The method for preparing an AD-A'-DA type fused-ring acceptor small molecule material based on anthracene bisthiadiazole according to claim 6, characterized in that, In step S3, when the molar ratio of the key intermediate ABT-2Br, the electron-donating D unit substituted with trialkyltin, and the palladium catalyst is 1:2.0~2.5:0.01~0.05, a symmetrical D-A'-D intermediate is obtained; when the molar ratio of the key intermediate ABT-2Br, the electron-donating D unit substituted with trialkyltin, and the palladium catalyst is 1:1.0~1.5:0.01~0.05, an asymmetrical D-A'-D intermediate is obtained; in step S4, when the molar ratio of the D-A'-D intermediate, the electron-withdrawing terminal A unit, and the organic base is 1:2.0~6.0:3.0~10.0, a symmetrical acceptor small molecule is obtained. Asymmetric acceptor small molecules are obtained by using a molar ratio of D-A'-D intermediate, electron-withdrawing terminal A unit, and organic base of 1:1.0~1.5:3.0~30.

0.

8. The application of an anthracene-bisthiadiazole-based AD-A'-DA type fused-ring acceptor small molecule material according to any one of claims 1-5 in solar cell devices, characterized in that, The application includes the following steps: one or more polymer donor materials selected from PM6, D18, PBQ6, and PTQ10 are blended with the AD-A'-DA type fused ring acceptor small molecule material based on anthracene bisthiadiazole as described in any one of claims 1-5 to form an active layer for the preparation of organic solar cell devices.

9. The application according to claim 8, characterized in that, The mass ratio of the polymer donor material to the anthracene-bisthiadiazole-based AD-A'-DA type fused ring acceptor small molecule material is 1:0.8-1:1.

5.

10. An organic solar cell device, characterized in that, The active layer comprises an active layer formed by blending an anthracene-bisthiadiazole-based AD-A'-DA type fused-ring acceptor small molecule material as described in any one of claims 1-5 with one or more polymer donor materials selected from PM6, D18, PBQ6, and PTQ10. The structure of the organic solar cell device is: substrate / transparent conductive electrode / hole transport layer / the active layer / electron transport layer / metal electrode, or an inverted structure: substrate / transparent conductive electrode / electron transport layer / the active layer / hole transport layer / metal electrode.

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