Conjugated small molecule containing acetylenic bond, preparation method of conjugated small molecule and application of conjugated small molecule in organic solar cell

Abstract

The invention relates to an acetylenic bond-containing conjugated small molecule, a preparation method thereof and an application in an organic solar cell, the acetylenic bond-containing conjugated small molecule is used as a third component to be applied to a photoactive layer of the organic solar cell, the photon absorption capability of the photoactive layer is greatly enhanced, the absorption range is widened, and the photoelectric conversion efficiency is improved. Compared with the prior art, accumulation of donor molecules is improved, crystallinity of the donor molecules is enhanced, aggregation of acceptors is delayed, then the efficient ternary organic solar cell is prepared, the device efficiency is improved, meanwhile, the preparation cost of three devices is effectively reduced, and the light stability of the organic solar cell is remarkably improved.

Description

Technical Field

[0001] The invention relates to a conjugated small molecule containing an alkyne bond, a preparation method thereof and application in an organic solar cell, and belongs to the field of organic solar cells. Background Art

[0002] Under the urgent need for global energy transformation, organic solar cells (OSCs) have become a key technology direction for achieving efficient solar energy utilization due to their lightweight and flexible properties, low-cost solution processing, and large-area fabrication. With the innovative development of non-fullerene acceptor materials, the power conversion efficiency (PCE) of single-junction OSCs has exceeded 20% (e.g.: B. Cheng, W. Hou, C. Han, S. Cheng, X. Xia, X. Guo, Y. Li, and M. Zhang, Energy Environ. Sci., 2025, 18, 1375; H. Lu, D. Li, W. Liu, G. Ran, H. Wu, N. Wei, Z. Tang, Y. Liu, W. Zhang, and Z. Bo, Angew. Chem. Int. Ed., 2024, 63, e202407007; L. Zhu, M. Zhang, G. Zhou, Z. Wang, W. Zhong, J. Zhuang, Z. Zhou, X. Gao, L. Kan, B. Hao, F. Han, R. Zeng, X. Xue, S. Xu, H. Jing, B. Xiao, H. Zhu, Y. Zhang, and F. Liu, Joule, 2024, 8, 3153.)

[0003] However, due to the intertwined crystallization dynamics of the donor and acceptor materials during the thin film formation process, it is easy to cause disordered molecular stacking and improper phase separation size, which in turn affects the exciton dissociation efficiency and charge transfer performance. Its further commercialization is still subject to the core problem of regulating the active layer morphology.

[0004] The traditional bulk heterojunction (BHJ) active layer relies on a binary blend system, and its narrow absorption spectrum makes it difficult to fully utilize the solar spectrum. The ternary strategy introduces a third component to broaden the absorption range, which can increase the short-circuit current density (J SC), but faced multiple challenges in morphology control. Early studies adopted solvent strategies to promote preferential crystallization of the donor by optimizing the interaction between the solvent and the acceptor side chain. For example, enhancing the swelling effect of the solvent on the acceptor side chain to delay its aggregation (R. Zhang, H. Chen, T. Wang, L. Kobera, L. He, Y. Huang, J. Ding, B. Zhang, A. Khasbaatar, S. Nanayakkara, J. Zheng, W. Chen, Y. Diao, S. Abbrent, J. Brus, A. H. Coffey, C. Zhu, H. Liu, X. Lu, Q. Jiang, V. Coropceanu, J.-L. Brédas, Y. Li, Y. Li, and F. Gao, Nat. Energy, 2024, 10, 124; H. Chen, Y. Huang, R. Zhang, H. Mou, J. Ding, J. Zhou, Z. Wang, H. Li, W. Chen, J. Zhu, Q. Cheng, H. Gu, X. Wu, T. Zhang, Y. Wang, H. Zhu, Z. Xie, F. Gao, Y. Li, and Y. Li, Nat. Mater., 2025, 24, 444), thereby stabilizing the conformation of the donor molecule and constructing a hierarchical fiber network to improve the charge transfer path. However, this strategy is highly dependent on the acceptor side chain structure, limiting its universality.

[0005] The multicomponent strategy introduces multiple functional molecules such as nucleating agents and plasticizers (M. Zhang, L. Zhu, G. Zhou, T. Hao, C. Qiu, Z. Zhao, Q. Hu, B. W. Larson, H. Zhu, Z. Ma, Z. Tang, W. Feng, Y. Zhang, TP Russell, and F. Liu, Nat. Commun., 2021, 12, 309; B. Cheng, X. Xia, S. Cheng, C. Han, F. Sun, Z. Fu, W. Hou, F. Hua, H. Wang, W. Sun, Y. Huo, S. Ji, X. Guo, H. Yin, X. Du, X. Hao, Y. Li, M. Zhang, Adv. Mater., 2025, 2500357) to regulate the donor aggregation and acceptor crystallization kinetics respectively. For example, nucleating agents promote orderly nucleation of the donor, while plasticizers retard the growth of the acceptor crystals, thereby achieving a sequential crystallization pattern of "donor crystallization first, acceptor growth later," optimizing vertical phase distribution and phase separation size. However, multi-component systems face difficulties in regulation and stringent process parameters due to the complex interactions between the components, making it difficult to achieve stable morphology control and improve device performance.

[0006] To address these challenges, thiophene derivatives with dual donor / acceptor functionalities have entered the research field. Thiophene molecules have similar structures to donor materials and can promote the orderly stacking of donor molecules through strong π-π interactions (J. Gao, W. Wang, C. Zhan, Y. Hu, S. Xiao, X. Lu, and W. You, J. Mater. Chem. A 2018, 6, 20788; J. Zhou, L. Wang, C. Liu, C. Guo, C. Chen, Y. Sun, Y. Yang, J. Cheng, Z. Gan, Z. Chen, W. Sun, J. Zhou, W. Xia, D. Liu, W. Li, and T.Wang, J.Am.Chem.Soc.2024,146,34998.); the expansion of its conjugated structure (such as the thiophene unit) can effectively inhibit the excessive aggregation of receptors (H.Liu, K.Shi, J.Lai, S.Jeong, C.Zhu, J.Zhang, Z.-G.Zhang, C.Yang, B.Qiu, and Y.Li, Chin.J.Chem.2024,42,3234; S.Bao, H.Yang, H.Fan, J.Zhang, Z.Wei, C.Cui, and Y.Li, Adv. Mater. 2021, 33, 2105301.), while the introduction of electronegative groups (such as halogens) can enhance the dipole interaction with the receptor (H.Zhang, G.Ran, X.Cui, Y.Liu, Z.Yin, D.Li, X.Ma, W.Liu, H.Lu, R.Liu, L.Cai, W.Zhang, S.Guo, H.Li, J.Yu, Y.Lin, Y.Liu, G.Lu, Z.Ma, P.Cheng, Z.Bo, Adv. Energy Mater. 2023, 13, 2302063; W.Su, X.Zhou, Z.-F.Yao, H.Bai, Y.Duan, R.Sun, Y.Wu, Q.Wu, H.Qin, C.Zhao, W.Zhu, HYWoo, J.Min, Y.Li, W.Ma, and Q. Fan, Adv. Funct. Mater. 2024, 34, 2313744.), to further optimize the interfacial charge transfer.Based on this, the acetylenic bond as a strong electron-withdrawing conjugated extension unit has attracted attention (D. Luo, L. Zhang, J. Zeng, H. Zhang, L. Li, T. Dai, B. Xu, E. Zhou, A. K. Kyaw, Y. Chen, and W.-Y. Wong, Adv. Mater. 2024, 2410880; F. Yang, H. Fang, E. Guo, C. Xiao, Z. Lu, Y. Wang, H. Fan, A. Zhang, W. Lai, and W. Li, Angew. Chem. Int. Ed. 2025, 64, e202501302.) Its sp hybrid structure combines conjugation extension and electronegativity regulation, enabling dual mechanisms to control the active layer morphology. On the one hand, the alkyne bond enhances intermolecular π-π stacking and face-on orientation, promoting the formation of ordered nanofibrous structures of the donor and improving the continuity of the hole transport channel. On the other hand, its electronegativity slows the crystallization rate of the acceptor through non-covalent interactions such as CH…O / CH…N hydrogen bonds, preventing phase separation and size loss, and forming a gradient vertical phase distribution. Donors are enriched on the anode side for efficient hole transport, while the acceptors are orderly arranged on the cathode side to promote electron migration, simultaneously optimizing exciton dissociation and charge collection efficiency. At present, alkyne bonds have been applied as connecting units to oligomeric receptors (X.Shen, W.A.Memon, H.Lai, Y.Wang, S.Xiong, M.Ou, R.Sun, N.Zheng, and F.He, Nano Energy 2025, 141, 111085.), but there are no reports in the literature on the use of a third component containing an alkyne bond to regulate the morphology of the active layer. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present invention provides a conjugated small molecule containing an alkyne bond, a preparation method thereof, and an application thereof in organic solar cells.

[0008] The application of the alkyne-containing conjugated small molecule of the present invention as the third component in the photoactive layer of an organic solar cell greatly enhances the photoactive layer's ability to absorb photons, broadens the absorption range, improves the stacking of donor molecules, enhances the crystallinity of donor molecules, and delays receptor aggregation. The decoupling of donor and receptor molecules during the film formation process enables sequential crystallization, thereby optimizing the phase separation and vertical phase distribution of the photoactive layer. Furthermore, the alkyne-containing conjugated small molecule of the present invention can regulate the morphology of the active layer, further improving the morphology of the photoactive layer and effectively increasing the device's current (J). sc ) and fill factor (FF), ultimately improving the photoelectric conversion performance of the battery device. The ternary organic solar cell prepared by the present invention has good thermal stability and storage stability.

[0009] The present invention is achieved through the following technical solutions:

[0010] A conjugated small molecule containing an acetylenic bond, wherein the conjugated small molecule is a conjugated organic small molecule with an acetylenic bond as a bridging unit and has the following general structural formula I:

[0011]

[0012] In Formula I,

[0013] X is any one of O, S or Se;

[0014] R1 and R2 are independently selected from hydrogen, C1-C 30 Alkyl, C1~C 30 Any one of an alkoxy group or a 4-alkylphenyl group, wherein the alkyl group in the 4-alkylphenyl group is any one of a C1 to C8 alkyl group;

[0015] Ar1 and Ar2 are independently selected from any one of the following groups which are unsubstituted or substituted:

[0016] Vinylene, ethynylene, monocyclic arylene, bicyclic arylene, arylene containing at least three rings, monocyclic heteroarylene, bicyclic heteroarylene, or heteroarylene containing at least three rings, wherein the rings of the bicyclic arylene, arylene containing at least three rings, bicyclic heteroarylene, or heteroarylene containing at least three rings are fused or connected by a single bond;

[0017] According to a preferred embodiment of the present invention, in Formula I, X is S; and R1 and R2 are independently selected from hydrogen.

[0018] The second object of the present invention is to provide a method for preparing the above-mentioned organic small molecules containing acetylenic bonds.

[0019] The method for preparing the above-mentioned organic small molecule containing an acetylenic bond comprises the following steps:

[0020] (1) Compound 1 was dissolved in a mixed solvent a of chloroform and acetic acid, and N-iodosuccinimide was slowly added in an ice-water bath while shielding from light. After half an hour, the ice-water bath was removed, and the reaction was stirred at room temperature for 48 hours. Compound 2-1 was obtained after separation and purification.

[0021] (2) Compound 2-1, bistriphenylphosphine palladium dichloride and cuprous iodide were added to a mixed solvent b of tetrahydrofuran and triethylamine, trimethylsilyl acetylene was added dropwise under an inert gas atmosphere, and the mixture was stirred at room temperature for 2-6 hours to separate and purify to obtain compound 3;

[0022] (3) Compound 3 and potassium carbonate were added to a mixed solvent c of tetrahydrofuran and methanol, and stirred at room temperature for 10-14 hours to separate and purify to obtain compound 4;

[0023] (4) Compound 2-2, bistriphenylphosphine palladium dichloride, and cuprous iodide are added to a mixed solvent d of toluene and diisopropylamine to obtain a mixture, compound 4 is dissolved in a mixed solvent e of toluene and diisopropylamine and then added to the mixture, stirred for 12-18 hours, and separated and purified to obtain compound 5;

[0024] (5) The compound 5, a tributyltin compound, potassium carbonate, and tetrakistriphenylphosphine palladium are stirred and reacted in deoxygenated toluene at a temperature of 100-140° C. under an inert gas atmosphere for 15-20 hours. After separation and purification, a conjugated small molecule product 6 having a structure of formula I and based on an acetylenic bond as a bridging unit is obtained:

[0025] The reaction route is as follows:

[0026]

[0027] Furthermore, the steps (2), (4) and (5) are all carried out under an inert gas atmosphere with stirring.

[0028] Preferably, according to the present invention, in step (1), the volume ratio of chloroform to acetic acid in the mixed solvent a is (1-5):1, the volume ratio of the molar amount of compound 1 to the mixed solvent a is (40-60):(100-300), unit, mmol / mL, and the molar ratio of N-iodosuccinimide to compound 1 is (4-8):(3-6).

[0029] According to the present invention, preferably, in step (2), the volume ratio of tetrahydrofuran to triethylamine in the mixed solvent b is 1:1, the molar ratio of compound 2-1, bistriphenylphosphine palladium dichloride, and cuprous iodide is (70-80): (0.5-1.5): (1-3), the volume ratio of the molar amount of compound 2-1 to the mixed solvent b is (70-80): (70-90), unit, mmol / mL, and the molar ratio of trimethylsilyl acetylene to compound 2-1 is (90-100): (70-80).

[0030] According to the present invention, preferably, in step (3), the volume ratio of tetrahydrofuran to methanol in the mixed solvent c is 1:1, the volume ratio of the molar amount of compound 3 to the mixed solvent c is (75-80): (77-82), unit, mmol / mL, and the molar ratio of compound 3 to potassium carbonate is (90-100): (10-20).

[0031] According to the present invention, preferably, in step (4), the volume ratio of toluene to diisopropylamine in the mixed solvent d is (2-4): 1, the molar ratio of compound 2-2, bistriphenylphosphine palladium dichloride and cuprous iodide is (1-3): (0.01-0.05): (0.04-0.08), and the volume ratio of the molar amount of compound 2-2 to the mixed solvent d is (1-3): (3-6), unit, mmol / mL.

[0032] According to the present invention, preferably, in step (4), the volume ratio of toluene to diisopropylamine in the mixed solvent e is 1: (2-4), and the volume ratio of the molar amount of compound 4 to the mixed solvent e is (1-5): (3-6), unit, mmol / mL.

[0033] According to the present invention, preferably, in step (5), the tributyltin compound is 2-(tributyltin)thiophene, the molar ratio of the amount of tetrakis(triphenylphosphine)palladium added to compound 5 is 1:10-100, the molar ratio of compound 5, 2-(tributyltin)thiophene, and potassium carbonate is (0.5-2):(1-5):(2-6), and the volume ratio of the molar amount of compound 5 to deoxygenated toluene is (0.5-2):(4-15), unit, mmol / mL.

[0034] The third object of the present invention is to provide an application of a conjugated small molecule containing an alkyne bond in an organic solar cell.

[0035] The above-mentioned conjugated small molecule containing an alkyne bond is used in an organic solar cell as a third component added to a photoactive layer. The photoactive layer contains the following components by weight: 0.5-10 parts of the above-mentioned conjugated small molecule containing an alkyne bond, 40.9-45.5 parts of an electron donor material, and 49.1-54.5 parts of an electron acceptor material.

[0036] According to the preferred embodiment of the present invention, the photoactive layer contains the following components by weight: 1 part of the above-mentioned conjugated small molecule containing an acetylenic bond, 45 parts of an electron donor material, and 54 parts of an electron acceptor material.

[0037] Adding the conjugated small molecule of the present invention to the photoactive layer broadens the absorption spectrum of the active layer, and because there is effective energy transfer between the conjugated small molecule and the electron donor material, the current (J sc ). In addition, the addition of conjugated small molecules significantly improves the stacking of donor molecules and enhances their crystallinity. The interaction with the acceptor delays the aggregation and precipitation of the acceptor, optimizes the morphology of the active layer, and is conducive to the transfer of charges and the improvement of carrier mobility, thereby improving the photoelectric conversion performance of the battery device.

[0038] Furthermore, when the content of conjugated small molecules containing acetylenic bonds is too low, their effect on improving device performance is not obvious; when their content is too high, it will cause excessive phase separation in the active layer, destroy the morphology of the active layer, and be unfavorable for the dissociation of excitons and the transfer of charges, thereby being detrimental to improving device performance.

[0039] Preferably according to the present invention, the conjugated small molecule absorbs short wavelength light in the wavelength range of 300-450 nm.

[0040] According to the present invention, the conjugated small molecule is preferably dithiophene acetylene (DBTE), which has the following general structural formula I-1:

[0041]

[0042] According to the present invention, the electron donor material is preferably PM6 and / or D18. According to the present invention, the electron acceptor material is preferably Y6 and / or L8-BO. ​​The PM6 structural formula is as follows:

[0043]

[0044] The structural formula of D18 is as follows:

[0045]

[0046] The structural formula of Y6 is as follows:

[0047]

[0048] The structural formula of L8-BO is as follows:

[0049]

[0050] In the above structural formula, n is the degree of polymerization, n=1-100, and R=ethylhexyl.

[0051] The conjugated small molecules containing acetylenic bonds of the present invention have no special restrictions on the types of electron donor materials and electron acceptor materials. As long as the requirements of energy level matching and compatibility are met and they can be assembled into solar cells, they can be used. Furthermore, from the perspective of improving the photoelectric conversion performance and life of the battery device, the electron donor material is preferably PM6 and the electron acceptor material is preferably Y6.

[0052] The preparation method of the photoactive layer is as follows:

[0053] The conjugated small molecule, the electron donor material and the electron acceptor material are dissolved in an organic solvent, and the obtained mixed solution is spin-coated on the surface of the hole transport layer to obtain a photoactive layer, and the organic solvent is chloroform.

[0054] A ternary organic solar cell comprises the photoactive layer of the present invention.

[0055] A ternary organic solar cell adopts a forward structure and includes, from bottom to top, a conductive substrate, a hole transport layer, a photoactive layer, a cathode interface modification layer, and a metal electrode. The thickness of the photoactive layer is 80-120nm.

[0056] The thickness of the photoactive layer of the present invention enables the battery device to have higher energy conversion efficiency.

[0057] The present invention has no special requirements on the configuration of the battery device including the photoactive layer, and it can be assembled into a forward device structure or a reverse device structure.

[0058] According to the present invention, preferably, the conductive substrate is ITO.

[0059] According to the present invention, the hole transport layer material is PEDOT:PSS with a thickness of 20-40 nm, the cathode interface modification layer material is PDINN or PNDIT-F3N with a thickness of 5-20 nm, and the metal electrode material is Ag or Al with a thickness of 80-120 nm.

[0060] The hole transport layer material and cathode interface modification layer material of the present invention are prepared according to the prior art.

[0061] The preparation method of the ternary organic solar cell comprises the following steps:

[0062] A hole transport layer, a photoactive layer, a cathode interface modification layer and a metal electrode are sequentially formed on the surface of a conductive substrate. Except for the process of forming the hole transport layer and the photoactive layer, thermal annealing is not required in other steps.

[0063] The technical features and advantages of the present invention are as follows:

[0064] 1. The alkyne-bonded conjugated small molecule of the present invention is a conjugated organic small molecule with an alkyne bond as a bridging unit, which can be processed by a solution method and is soluble in organic solvents such as chloroform, tetrahydrofuran and chlorobenzene;

[0065] 2. The conjugated small molecule containing an alkyne bond of the present invention has good thermal stability, and the initial thermal decomposition temperature exceeds 270°C;

[0066] 3. The alkyne-bonded conjugated small molecules of the present invention have good light absorption and are suitable for use as organic solar cell materials;

[0067] 4. The alkyne-bond-containing conjugated small molecule of the present invention is applied as the third component to the photoactive layer of an organic solar cell, which greatly enhances the photoactive layer's ability to absorb photons, broadens the absorption range, improves the stacking of donor molecules, enhances the crystallinity of donor molecules, and delays receptor aggregation, thereby preparing high-efficiency ternary organic solar cells. While improving device efficiency, it effectively reduces the preparation cost of ternary devices and significantly improves the photostability of organic solar cells.

[0068] 5. The introduction of the alkyne-containing conjugated small molecules of the present invention into different binary photoactive layer systems effectively improved the device efficiency, demonstrating the universal applicability of conjugated small molecules in improving the performance of organic solar cells, broadening the application field of conjugated small molecules, and providing a new direction for finding suitable third component materials for ternary organic solar cells.

[0069] 6. The preparation process of the ternary organic solar cell based on conjugated small molecules provided by the present invention is simple, short in process and low in cost, which is conducive to large-scale industrial production.

[0070] 7. This invention solves the long-standing challenge of the inability to achieve sequential crystallization through the bifunctionalization of conjugated small molecules containing alkyne bonds, providing a new strategy for the design of traditional bulk heterojunction (BHJ) morphology, and paving the way for high-performance OSCs with balanced crystallinity, fine phase separation and strong charge dynamics. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without inventive work.

[0072] Figure 1 The UV-visible absorption spectra of the organic small molecules containing alkyne bonds, PM6 and Y6 prepared in Example 1;

[0073] Figure 2 1 is a cyclic voltammetry curve of the organic small molecule containing an alkyne bond prepared in Example 1;

[0074] Figure 3 This is a thermogravimetric analysis curve of the organic small molecule containing an alkyne bond prepared in Example 1;

[0075] Figure 4 JV curves of organic small molecules containing alkyne bonds applied in organic solar cells based on PM6 and Y6;

[0076] Figure 5JV curves of organic small molecules containing alkyne bonds applied in organic solar cells based on D18 and L8-BO. DETAILED DESCRIPTION

[0077] To make the above-mentioned objects, features and advantages of the present invention more clearly understood, the technical solutions of the present invention are further described below with reference to the accompanying drawings and embodiments. However, the present invention is not limited to the embodiments listed, but also includes any other known modifications within the scope of the claimed invention.

[0078] First, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0079] Secondly, the present invention is described in detail using schematic diagrams. For ease of explanation, the schematic diagrams may be partially enlarged and not to scale when describing the embodiments of the present invention. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. Furthermore, in actual production, the three-dimensional space of length, width, and depth should be included.

[0080] Example 1

[0081] The preparation method of organic small molecules containing acetylenic bonds has the following reaction route:

[0082]

[0083] The specific steps are as follows:

[0084] Step 1) Synthesis of compound 3-bromo-2-iodothiophene:

[0085] Compound 1 (8.15 g, 50.0 mmol), 3-bromothiophene, was placed in a 250 mL single-necked round-bottom flask. Chloroform (100 mL) and acetic acid (50 mL) were then added. N-iodosuccinimide (13.50 g, 60.0 mmol) was slowly added to the flask in an ice-water bath and protected from light. After the addition of N-iodosuccinimide, a spherical drying tube with anhydrous magnesium sulfate was placed over the flask. After half an hour, the ice-water bath was removed and the reaction was stirred at room temperature for 48 hours. The organic solvent was removed using a rotary evaporator, and the mixture was neutralized with sodium bicarbonate (1 M, 250 mL). Extraction was then performed with n-hexane. The organic phase was dried over anhydrous magnesium sulfate and the solvent removed using a rotary evaporator. Finally, the product was distilled to yield compound 2 (5.04 g, 35%) as a bright orange oil, 3-bromo-2-iodothiophene.

[0086] The structural confirmation data are as follows:1 H NMR (400MHz, CDCl3) δ7.41 (d, J = 5.6 Hz, 1H), 6.90 (d, J = 5.6 Hz, 1H).

[0087] Step 2) Synthesis of the compound ((3-bromothiophen-2-yl)ethynyl)trimethylsilane:

[0088] Compound 2 (22.53 g, 77.97 mmol), bistriphenylphosphine palladium dichloride (547.27 mg, 0.78 mmol), and cuprous iodide (296.99 mg, 1.56 mmol) were added to a mixture of tetrahydrofuran (40 mL) and triethylamine (40 mL). Trimethylsilylacetylene (15 mL, 93.57 mmol) was added dropwise under an inert atmosphere. After stirring at room temperature for 4 hours, the mixture was filtered through celite. The filtrate was concentrated under reduced pressure and then passed through a short silica gel column with a 5 / 1 hexane / ethyl acetate mixture as the eluent to obtain the crude product 3, ((3-bromothien-2-yl)ethynyl)trimethylsilane. This product was used directly in the next desilylation reaction without further purification.

[0089] The structural confirmation data are as follows: 1 H NMR (400MHz, CDCl3) δ7.41 (d, J = 5.6 Hz, 1H), 6.90 (d, J = 5.6 Hz, 1H).

[0090] Step 3) Synthesis of compound 3-bromo-2-ethynylthiophene:

[0091] Compound 3 and potassium carbonate (1.08 g, 7.80 mmol) were added to a mixture of tetrahydrofuran (40 mL) and methanol (40 mL). After stirring at room temperature for 12 hours, the mixture was neutralized with hydrochloric acid (1 M, 7 mL) and extracted with dichloromethane. The organic phase was dried over anhydrous magnesium sulfate, filtered, and the solvent removed on a rotary evaporator. The resulting crude product was separated by column chromatography using petroleum ether / ethyl acetate (1:1) as the eluent to afford compound 4 (8.90 g, 61% yield), 3-bromo-2-ethynylthiophene, as a colorless oil.

[0092] The structural confirmation data are as follows: 1 H NMR (400MHz, CDCl3) δ7.22 (d, J = 5.4Hz, 1H), 6.97 (d, J = 5.4Hz, 1H), 3.59 (s, 1H).

[0093] Step 4) Synthesis of compound 1,2-bis(3-bromothiophen-2-yl)acetylene:

[0094] Compound 2 (649.7 mg, 2.25 mmol), bistriphenylphosphine palladium dichloride (15.78 mg, 0.02 mmol), and cuprous iodide (8.56 mg, 0.05 mmol) were added to a mixture of toluene (3 mL) and diisopropylamine (1 mL). Compound 4 (420.6 mg, 2.25 mmol) was dissolved in a mixture of toluene (1 mL) and diisopropylamine (3 mL) and added to the mixture with a syringe. After stirring for 15 hours, the mixture was neutralized with hydrochloric acid (1 M, 2 mL) and extracted with dichloromethane. The organic phase was dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography using dichloromethane / ethyl acetate (50:1) as the eluent and recrystallized from a mixture of n-hexane / ethyl acetate to afford compound 5 (360 mg, 46% yield) as white crystals, namely, 1,2-bis(3-bromothien-2-yl)acetylene.

[0095] The structural confirmation data are as follows: 1 H NMR (400MHz, CDCl3) δ7.28 (d, J = 5.4Hz, 1H), 7.00 (d, J = 5.4Hz, 1H). 13 C NMR(101MHz, CDCl3)δ130.44,130.35,129.07,127.97,119.65,118.90,81.18,75.99.HRMS(ESI,m / z)calcd for C 10 H4Br2S2:348.8179;[M+H]+found:348.8173.

[0096] Step 5) Synthesis of compound 1,2-bis([2,3'-bithiophene]-2'-yl)acetylene (DBTE):

[0097] Compound 5 (350 mg, 1.01 mmol), 2-(tributyltinyl)thiophene (868.71 mg, 2.33 mmol), potassium carbonate (420 g, 3.03 mmol), and tetrakis(triphenylphosphine)palladium (58.48 mg, 0.051 mmol) were stirred in deoxygenated toluene (8 mL) at 120°C under an inert atmosphere. The mixture was then filtered through celite and the solvent removed using a rotary evaporator. The crude product was separated by silica gel column chromatography using petroleum ether as the eluent to obtain DBTE as a yellow solid (290 mg, 81% yield), i.e., 1,2-bis(2,3'-bithiophene]-2'-yl)acetylene.

[0098] The structural confirmation data are as follows: 1H NMR (400MHz, CDCl3) δ7.61 (dd, J=3.7, 1.2Hz, 2H), 7.33-7.23 (m, 6H), 7.06 (dd, J=5.1, 3.6Hz, 2H). 13 C NMR(101MHz, CDCl3)δ138.27,137.80,127.55,127.42,127.01,125.52,125.23,116.27,91.41.HRMS(ESI,m / z)calcd forC 18 H 10 S4:354.9744;[M+H]+found:354.9738.

[0099] The UV-visible absorption spectrum of the prepared organic small molecule containing alkyne bond is as follows Figure 1 As shown in the cyclic voltammetry curve, Figure 2 The thermogravimetric analysis curve is shown in Figure 3 shown.

[0100] pass Figure 1 It can be seen that the small molecule DBTE has strong absorption in the 300-450 nm range, which complements the absorption of the active layer materials PM6 and Y6;

[0101] pass Figure 2 It can be seen that the initial oxidation potential of small molecule DBTE is 0.78V vs Ag / Ag + By formula It can be calculated that the HOMO energy level of DBTE is -5.44 eV;

[0102] pass Figure 3 It can be seen that when the weight of small molecule DBTE loses 5%, the thermal decomposition temperature (T d ) is 276 °C, indicating that the small molecule DBTE has good stability;

[0103] Example 2

[0104] The forward-structured ternary organic solar cell includes, from bottom to top, a conductive substrate, a hole transport layer, a photoactive layer, a cathode interface modification layer, and a metal electrode.

[0105] The preparation method comprises the following steps:

[0106] Clean the ITO glass substrate. Use a nitrogen gun to blow off any surface solvent. Place the substrate in an oven for approximately 10-15 minutes to further remove surface solvents. Perform a UV-ozone clean for approximately 20 minutes. Spin-coat PEDOT:PSS (6000 rpm / min, 40 seconds, 30 nm thickness) onto the ITO glass substrate to create a hole transport layer. Thermally anneal the resulting film (150°C, 15 minutes). Then, a PM6:DBTE:Y6 photoactive layer (about 100 nm thick) was spin-coated on the hole transport layer, with PM6:Y6 = 1:1.2 (wt%:wt%), PM6 accounting for 45.2% of the total mass of the photoactive layer, Y6 accounting for 54.3% of the total mass of the photoactive layer, and DBTE accounting for 0.5% of the total mass of the photoactive layer. Specifically, PM6, Y6 and DBTE were all dissolved in chloroform solvent (PM6 concentration was 8 mg / mL), heated to 50°C for about 2 hours, and then 0.75% chloronaphthalene was added to the mixed solution (the volume of chloronaphthalene accounted for 0.75% of the total volume of the photoactive layer solution). After the chloronaphthalene was added and dissolved for 30 minutes, the mixed solution was spin-coated on the surface of the hole transport layer to form a photoactive layer after spin coating was completed. Then, thermal annealing was performed at 80°C for 10 minutes. Then, a cathode interface layer PNDIT-F3N solution (dissolved in a mixture of methanol and acetic acid (99.5:0.5), with a concentration of 0.5 mg / mL) was spin-coated on the surface of the photoactive layer. Finally, metal Al (100 nm thick) was evaporated on the surface of the cathode interface layer (10 nm thick). Under standard test conditions (AM1.5G, 100 mW cm -2 ), and the open circuit voltage of the device is measured (V OC )=0.857V, short-circuit current (J SC )=27.5mAcm -2 , fill factor (FF) = 78.5%, photoelectric conversion efficiency (PCE) = 18.6%.

[0107] Example 3

[0108] The forward-structured ternary organic solar cell includes, from bottom to top, a conductive substrate, a hole transport layer, a photoactive layer, a cathode interface modification layer, and a metal electrode.

[0109] The preparation method comprises the following steps:

[0110] Clean the ITO glass substrate. Use a nitrogen gun to blow off any surface solvent. Place the substrate in an oven for approximately 10-15 minutes to further remove surface solvents. Perform a UV-ozone clean for approximately 20 minutes. Spin-coat PEDOT:PSS (6000 rpm / min, 40 seconds, 30 nm thickness) onto the ITO glass substrate to create a hole transport layer. Thermally anneal the resulting film (150°C, 15 minutes). Then, a PM6:DBTE:Y6 photoactive layer (about 100 nm thick) was spin-coated on the hole transport layer, with PM6:Y6 = 1:1.2 (wt%:wt%), PM6 accounting for 45% of the total mass of the photoactive layer, Y6 accounting for 54% of the total mass of the photoactive layer, and DBTE accounting for 1% of the total mass of the photoactive layer. Specifically, PM6, Y6 and DBTE were all dissolved in chloroform solvent (donor concentration was 8 mg / mL), heated to 50°C for about 2 hours, and then 0.75% chloronaphthalene was added to the mixed solution (the volume of chloronaphthalene accounted for 0.75% of the total volume of the photoactive layer solution). After the chloronaphthalene was added and dissolved for 30 minutes, the mixed solution was spin-coated on the surface of the hole transport layer to form a photoactive layer after spin coating. Then, thermal annealing was performed at 80°C for 10 minutes. Then, a cathode interface layer PNDIT-F3N solution (dissolved in a mixture of methanol and acetic acid (99.5:0.5), with a concentration of 0.5 mg / mL) was spin-coated on the surface of the photoactive layer. Finally, metal Al (100 nm thick) was evaporated on the surface of the cathode interface layer (10 nm thick). Under standard test conditions (AM1.5G, 100 mW cm -2 ), and the open circuit voltage of the device is measured (V OC )=0.857V, short-circuit current (J SC )=27.8mAcm -2 , fill factor (FF) = 79.1%, photoelectric conversion efficiency (PCE) = 18.9%.

[0111] Example 4

[0112] The forward-structured ternary organic solar cell includes, from bottom to top, a conductive substrate, a hole transport layer, a photoactive layer, a cathode interface modification layer, and a metal electrode.

[0113] The preparation method comprises the following steps:

[0114] Clean the ITO glass substrate. Use a nitrogen gun to blow off any surface solvent. Place the substrate in an oven for approximately 10-15 minutes to further remove surface solvents. Perform a UV-ozone clean for approximately 20 minutes. Spin-coat PEDOT:PSS (6000 rpm / min, 40 seconds, 30 nm thickness) onto the ITO glass substrate to create a hole transport layer. Thermally anneal the resulting film (150°C, 15 minutes). Then, a PM6:Y6:DBTE photoactive layer (about 100 nm thick) was spin-coated on the hole transport layer, with PM6:Y6 = 1:1.2 (wt%:wt%), PM6 accounting for 44.8% of the total mass of the photoactive layer, Y6 accounting for 53.7% of the total mass of the photoactive layer, and DBTE accounting for 1.5% of the total mass of the photoactive layer. Specifically, PM6, Y6 and DBTE were all dissolved in chloroform solvent (donor concentration was 8 mg / mL), heated to 50°C for about 2 hours, and then 0.75% naphthalene chloride was added to the mixed solution (the volume of naphthalene chloride accounted for 0.75% of the total volume of the photoactive layer solution). After the naphthalene chloride was added and dissolved for 30 minutes, the mixed solution was spin-coated on the surface of the hole transport layer to form a photoactive layer after spin coating. Then, thermal annealing was performed at 80°C for 10 minutes. Then, a cathode interface layer PNDIT-F3N solution (dissolved in a mixture of methanol and acetic acid (99.5:0.5), with a concentration of 0.5 mg / mL) was spin-coated on the surface of the photoactive layer. Finally, metal Al (100 nm thick) was evaporated on the surface of the cathode interface layer (10 nm thick). Under standard test conditions (AM1.5G, 100 mW cm -2 ), and the open circuit voltage of the device is measured (V OC )=0.861V, short-circuit current (J SC )=27.6mA cm -2 , fill factor (FF) = 77.6%, photoelectric conversion efficiency (PCE) = 18.4%.

[0115] Example 5

[0116] The forward-structured ternary organic solar cell includes, from bottom to top, a conductive substrate, a hole transport layer, a photoactive layer, a cathode interface modification layer, and a metal electrode.

[0117] The preparation method comprises the following steps:

[0118] Clean the ITO glass substrate. Use a nitrogen gun to blow off any surface solvent. Place the substrate in an oven for approximately 10-15 minutes to further remove surface solvents. Perform a UV-ozone clean for approximately 20 minutes. Spin-coat PEDOT:PSS (6000 rpm / min, 40 seconds, 30 nm thickness) onto the ITO glass substrate to create a hole transport layer. Thermally anneal the resulting film (150°C, 15 minutes). Then, a PM6:Y6:DBTE photoactive layer (about 100 nm thick) was spin-coated on the hole transport layer, with PM6:Y6 = 1:1.2 (wt%:wt%), PM6 accounting for 44.5% of the total mass of the photoactive layer, Y6 accounting for 53.5% of the total mass of the photoactive layer, and DBTE accounting for 2% of the total mass of the photoactive layer. Specifically, PM6, Y6 and DBTE were all dissolved in chloroform solvent (donor concentration was 8 mg / mL), heated to 50°C for about 2 hours, and then 0.75% naphthalene chloride was added to the mixed solution (the volume of naphthalene chloride accounted for 0.75% of the total volume of the photoactive layer solution). After the naphthalene chloride was added and dissolved for 30 minutes, the mixed solution was spin-coated on the surface of the hole transport layer to form a photoactive layer after spin coating. Then, thermal annealing was performed at 80°C for 10 minutes. Then, a cathode interface layer PNDIT-F3N solution (dissolved in a mixture of methanol and acetic acid (99.5:0.5), with a concentration of 0.5 mg / mL) was spin-coated on the surface of the photoactive layer. Finally, metal Al (100 nm thick) was evaporated on the surface of the cathode interface layer (10 nm thick). Under standard test conditions (AM1.5G, 100 mW cm -2 ), and the open circuit voltage of the device is measured (V OC )=0.863V, short-circuit current (J SC )=27.5mAcm -2 , fill factor (FF) = 77.1%, photoelectric conversion efficiency (PCE) = 18.3%.

[0119] Example 6

[0120] The forward-structured ternary organic solar cell includes, from bottom to top, a conductive substrate, a hole transport layer, a photoactive layer, a cathode interface modification layer, and a metal electrode.

[0121] The preparation method comprises the following steps:

[0122] Clean the ITO glass substrate. Use a nitrogen gun to blow off any surface solvent. Place the substrate in an oven for approximately 10-15 minutes to further remove surface solvents. Perform a UV-ozone clean for approximately 20 minutes. Spin-coat PEDOT:PSS (6000 rpm / min, 40 seconds, 30 nm thickness) onto the ITO glass substrate to create a hole transport layer. Thermally anneal the resulting film (150°C, 15 minutes). Then, a PM6:Y6:DBTE photoactive layer (about 100 nm thick) was spin-coated on the hole transport layer, with PM6:Y6 = 1:1.2 (wt%:wt%), PM6 accounting for 40.9% of the total mass of the photoactive layer, Y6 accounting for 49.1% of the total mass of the photoactive layer, and DBTE accounting for 10% of the total mass of the photoactive layer. Specifically, PM6, Y6 and DBTE were all dissolved in chloroform solvent (donor concentration was 8 mg / mL), heated to 50°C for about 2 hours, and then 0.75% chloronaphthalene was added to the mixed solution (the volume of chloronaphthalene accounted for 0.75% of the total volume of the photoactive layer solution). After the chloronaphthalene was added and dissolved for 30 minutes, the mixed solution was spin-coated on the surface of the hole transport layer to form a photoactive layer after spin coating. Then, thermal annealing was performed at 80°C for 10 minutes. Then, a cathode interface layer PNDIT-F3N solution (dissolved in a mixture of methanol and acetic acid (99.5:0.5), with a concentration of 0.5 mg / mL) was spin-coated on the surface of the photoactive layer. Finally, metal Al (100 nm thick) was evaporated on the surface of the cathode interface layer (10 nm thick). Under standard test conditions (AM1.5G, 100 mW cm -2 ), and the open circuit voltage of the device is measured (V OC )=0.835V, short-circuit current (J SC )=27.4mAcm -2 , fill factor (FF) = 72.5%, photoelectric conversion efficiency (PCE) = 16.6%.

[0123] Example 7

[0124] The forward-structured ternary organic solar cell includes, from bottom to top, a conductive substrate, a hole transport layer, a photoactive layer, a cathode interface modification layer, and a metal electrode.

[0125] The preparation method comprises the following steps:

[0126] Clean the ITO glass substrate. Use a nitrogen gun to blow off any surface solvent. Place the substrate in an oven for approximately 10-15 minutes to further remove surface solvents. Perform a UV-ozone clean for approximately 20 minutes. Spin-coat PEDOT:PSS (6000 rpm / min, 40 seconds, 30 nm thickness) onto the ITO glass substrate to create a hole transport layer. Thermally anneal the resulting film (150°C, 15 minutes). A D18:DBTE:L8-BO photoactive layer (approximately 100 nm thick) was then spin-coated on the hole transport layer. The ratio of D18:L8-BO was 1:1.2 (wt%:wt%), with D18 accounting for 45% of the total mass of the photoactive layer, L8-BO accounting for 54% of the total mass of the photoactive layer, and DBTE accounting for 1% of the total mass of the photoactive layer. Specifically, D18, L8-BO, and DBTE were dissolved in chloroform (donor concentration was 5.5 mg / mL) and heated at 80°C for approximately 2 hours. Then, 0.75% chloronaphthalene was added to the mixed solution (the volume of chloronaphthalene accounted for 0.75% of the total volume of the photoactive layer solution). The prepared chloronaphthalene-containing solution was spin-coated on the surface of the hole transport layer and then thermally annealed at 80°C for 10 minutes to form the photoactive layer. Then, a cathode interface layer PNDIT-F3N solution (dissolved in a mixture of methanol and acetic acid (99.5:0.5), with a concentration of 0.5 mg / mL) was spin-coated on the surface of the photoactive layer. Finally, metal Al (100 nm thick) was evaporated on the surface of the cathode interface layer (10 nm thick). Under standard test conditions (AM1.5G, 100 mW cm -2 ), and the open circuit voltage of the device is measured (V OC )=0.919V, short-circuit current (J SC )=27.6mAcm -2 , fill factor (FF) = 80.4%, photoelectric conversion efficiency (PCE) = 20.4%.

[0127] Figure 4 The JV curves of organic small molecules containing alkyne bonds used in organic solar cells based on PM6 and Y6. Figure 4 As shown in the figure, the device performance is the best when DBTE accounts for 1% of the total mass of the photoactive layer, and the short-circuit current J SC 27.8 mA cm -2 , open circuit voltage V OC The voltage is 0.857V, the fill factor FF is 79.1%, and the power conversion efficiency PCE is 18.9%.

[0128] Figure 5 The JV curves of organic small molecules containing alkyne bonds in organic solar cells based on D18 and L8-BO. Figure 5 As shown in the figure, the device performance is the best when DBTE accounts for 1% of the total mass of the photoactive layer, and the short-circuit current J SC27.6 mA cm -2 , open circuit voltage V OC The voltage is 0.919V, the fill factor FF is 80.4%, and the power conversion efficiency PCE is 20.4%.

[0129] Comparative Example 1

[0130] The forward-structured ternary organic solar cell includes, from bottom to top, a conductive substrate, a hole transport layer, a photoactive layer, a cathode interface modification layer, and a metal electrode.

[0131] The preparation method comprises the following steps:

[0132] Clean the ITO glass substrate. Use a nitrogen gun to blow off the surface solvent, then place in an oven for approximately 10-15 minutes to further remove the surface solvent. Perform a UV-ozone clean for approximately 20 minutes. Spin-coat PEDOT:PSS (6000 rpm / min, 40 seconds, 30 nm thickness) on the ITO glass substrate to form a hole transport layer, and thermally anneal the resulting film (150°C, 15 minutes). Then, spin-coat a PM6:Y6 photoactive layer (approximately 100 nm thick) on the hole transport layer. The PM6:Y6 ratio is 1:1.2 (wt%:wt%), with PM6 comprising 45.5% and Y6 comprising 54.5% of the total mass of the photoactive layer. Specifically, PM6 and Y6 are dissolved in chloroform (donor concentration of 8 mg / mL) and heated at 50°C for approximately 2 hours. Then, 0.75% chloronaphthalene is added to the mixed solution (the volume of chloronaphthalene accounts for 0.75% of the total volume of the photoactive layer solution). The chlorinated naphthalene solution prepared above was spin-coated on the hole transport layer surface, followed by thermal annealing at 80°C for 10 minutes to form a photoactive layer. A cathode interface layer, PNDIT-F3N solution (dissolved in a mixture of methanol and acetic acid (99.5:0.5), with a PNDIT-F3N concentration of 0.5 mg / mL) was then spin-coated on the photoactive layer surface. Finally, Al (100 nm thick) was evaporated on the cathode interface layer (10 nm thick). Under standard test conditions (AM1.5G, 100 mW / cm -2 ), and the open circuit voltage of the device is measured (V OC )=0.855V, short-circuit current (J SC )=26.5mAcm -2 , fill factor (FF) = 77.8%, photoelectric conversion efficiency (PCE) = 17.6%.

[0133] Comparative Example 2

[0134] The forward-structured ternary organic solar cell includes, from bottom to top, a conductive substrate, a hole transport layer, a photoactive layer, a cathode interface modification layer, and a metal electrode.

[0135] The preparation method comprises the following steps:

[0136] Clean the ITO glass substrate. Use a nitrogen gun to blow off any surface solvent. Place the substrate in an oven for approximately 10-15 minutes to further remove surface solvents. Perform a UV-ozone clean for approximately 20 minutes. Spin-coat PEDOT:PSS (6000 rpm / min, 40 seconds, 30 nm thickness) onto the ITO glass substrate to create a hole transport layer. Thermally anneal the resulting film (150°C, 15 minutes). A D18:L8-BO photoactive layer (approximately 100 nm thick) was then spin-coated on the hole transport layer, with a D18:L8-BO ratio of 1:1.2 (wt%:wt%), where D18 accounted for 45.5% of the total mass of the photoactive layer and L8-BO accounted for 54.5% of the total mass of the photoactive layer. Specifically, D18 and L8-BO were dissolved in chloroform (donor concentration was 5.5 mg / mL) and heated at 80°C for approximately 2 hours. Then, 0.75% chloronaphthalene was added to the mixed solution (the volume of chloronaphthalene accounted for 0.75% of the total volume of the photoactive layer solution). The prepared chloronaphthalene-containing solution was spin-coated on the surface of the hole transport layer and then thermally annealed at 80°C for 10 minutes to form the photoactive layer. Then, a cathode interface layer PNDIT-F3N solution (dissolved in a mixture of methanol and acetic acid (99.5:0.5), with a concentration of 0.5 mg / mL) was spin-coated on the surface of the photoactive layer. Finally, metal Al (100 nm thick) was evaporated on the surface of the cathode interface layer (10 nm thick). Under standard test conditions (AM1.5G, 100 mW cm -2 ), and the open circuit voltage of the device is measured (V OC )=0.912V, short-circuit current (J SC )=26.1mAcm -2 , fill factor (FF) = 76.1%, photoelectric conversion efficiency (PCE) = 18.1%.

[0137] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

[0138] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the specification, the following are the characteristics and preferred embodiments of organic small molecules containing acetylenic bonds and detailed drawings as follows.

Claims

1. A conjugated small molecule containing an alkyne bond, wherein the conjugated small molecule is a conjugated organic small molecule with an alkyne bond as a bridging unit and has the following general structural formula I: In Formula I, X is any one of O, S or Se; R1 and R2 are independently selected from hydrogen, C1-C 30 Alkyl, C1~C 30 Any one of an alkoxy group or a 4-alkylphenyl group, wherein the alkyl group in the 4-alkylphenyl group is any one of a C1 to C8 alkyl group; Ar1 and Ar2 are independently selected from any one of the following groups which are unsubstituted or substituted: Vinylene, ethynylene, monocyclic arylene, bicyclic arylene, arylene containing at least three rings, monocyclic heteroarylene, bicyclic heteroarylene or heteroarylene containing at least three rings, wherein the rings of the bicyclic arylene, arylene containing at least three rings, bicyclic heteroarylene or heteroarylene containing at least three rings are fused or connected by a single bond.

2. The method for preparing the organic small molecule containing an acetylenic bond according to claim 1, comprising the following steps: (1) Compound 1 was dissolved in a mixed solvent a of chloroform and acetic acid, and N-iodosuccinimide was slowly added in an ice-water bath while shielding from light. After half an hour, the ice-water bath was removed, and the reaction was stirred at room temperature for 48 hours. Compound 2-1 was obtained after separation and purification. (2) Compound 2-1, bistriphenylphosphine palladium dichloride and cuprous iodide were added to a mixed solvent b of tetrahydrofuran and triethylamine, trimethylsilyl acetylene was added dropwise under an inert gas atmosphere, and the mixture was stirred at room temperature for 2-6 hours to separate and purify to obtain compound 3; (3) Compound 3 and potassium carbonate were added to a mixed solvent c of tetrahydrofuran and methanol, and stirred at room temperature for 10-14 hours to separate and purify to obtain compound 4; (4) Compound 2-2, bistriphenylphosphine palladium dichloride, and cuprous iodide are added to a mixed solvent d of toluene and diisopropylamine to obtain a mixture, compound 4 is dissolved in a mixed solvent e of toluene and diisopropylamine and then added to the mixture, stirred for 12-18 hours, and separated and purified to obtain compound 5; (5) The compound 5, a tributyltin compound, potassium carbonate, and tetrakistriphenylphosphine palladium are stirred and reacted in deoxygenated toluene at a temperature of 100-140° C. under an inert gas atmosphere for 15-20 hours. After separation and purification, a conjugated small molecule product 6 having a structure of formula I and based on an acetylenic bond as a bridging unit is obtained: The reaction route is as follows:

3. The method for preparing an organic small molecule containing an acetylenic bond according to claim 2, characterized in that: The steps (2), (4) and (5) are all stirred and reacted under an inert gas atmosphere. In step (1), the volume ratio of chloroform to acetic acid in the mixed solvent a is (1-5):1, the volume ratio of the molar amount of compound 1 to the mixed solvent a is (40-60):(100-300), the unit is mmol / mL, the molar ratio of N-iodosuccinimide to compound 1 is (4-8):(3-6), and in step (2), the mixed solvent The volume ratio of tetrahydrofuran to triethylamine in b is 1:1, the molar ratio of compound 2-1, bistriphenylphosphine palladium dichloride, and cuprous iodide is (70-80): (0.5-1.5): (1-3), the volume ratio of the molar amount of compound 2-1 to the mixed solvent b is (70-80): (70-90), unit, mmol / mL, and the molar ratio of trimethylsilylacetylene to compound 2-1 is (90-100): (70-80).

4. The method for preparing an organic small molecule containing an acetylenic bond according to claim 2, wherein: In step (3), the volume ratio of tetrahydrofuran to methanol in the mixed solvent c is 1:1, the volume ratio of the molar amount of compound 3 to the mixed solvent c is (75-80): (77-82), unit, mmol / mL, the molar ratio of compound 3 to potassium carbonate is (90-100): (10-20), in step (4), the volume ratio of toluene to diisopropylamine in the mixed solvent d is (2-4): 1, compound 2-2, bis(triphenylphosphine) dichloride The molar ratio of palladium and cuprous iodide is (1-3): (0.01-0.05): (0.04-0.08), the volume ratio of the molar amount of compound 2-2 to the mixed solvent d is (1-3): (3-6), unit, mmol / mL, the volume ratio of toluene and diisopropylamine in the mixed solvent e is 1: (2-4), and the volume ratio of the molar amount of compound 4 to the mixed solvent e is (1-5): (3-6), unit, mmol / mL.

5. The method for preparing an organic small molecule containing an acetylenic bond according to claim 2, characterized in that: In step (5), the tributyltin compound is 2-(tributyltin)thiophene, the molar ratio of tetrakis(triphenylphosphine)palladium added to compound 5 is 1:10-100, the molar ratio of compound 5, 2-(tributyltin)thiophene, and potassium carbonate is (0.5-2):(1-5):(2-6), and the volume ratio of the molar amount of compound 5 to deoxygenated toluene is (0.5-2):(4-15), unit, mmol / mL.

6. Use of the conjugated small molecule containing an acetylenic bond according to claim 1 in an organic solar cell, wherein the conjugated small molecule containing an acetylenic bond is added as a third component to a photoactive layer, wherein the photoactive layer comprises the following components by weight: 0.5-10 parts of the conjugated small molecule containing an acetylenic bond, 40.9-45.5 parts of an electron donor material, and 49.1-54.5 parts of an electron acceptor material. The conjugated small molecule absorbs short-wavelength light in the 300-450nm wavelength range, the electron donor material is PM6 and / or D18, and the electron acceptor material is Y6 and / or L8-BO.

7. The use according to claim 7, characterized in that The preparation method of the photoactive layer is as follows: The conjugated small molecule, the electron donor material and the electron acceptor material are dissolved in an organic solvent, and the obtained mixed solution is spin-coated on the surface of the hole transport layer to obtain a photoactive layer, and the organic solvent is chloroform.

8. A ternary organic solar cell, which adopts a forward structure and comprises, from bottom to top, a conductive substrate, a hole transport layer, the photoactive layer according to claim 7, a cathode interface modification layer, and a metal electrode, wherein the thickness of the photoactive layer is 80-120 nm.

9. The ternary organic solar cell according to claim 8, characterized in that: The conductive substrate is ITO, the hole transport layer material is PEDOT:PSS with a thickness of 20-40nm, the cathode interface modification layer material is PDINN or PNDIT-F3N with a thickness of 5-20nm, and the metal electrode material is Ag or Al with a thickness of 80-120nm.

10. The method for preparing the ternary organic solar cell according to claim 9, comprising the following steps: A hole transport layer, a photoactive layer, a cathode interface modification layer and a metal electrode are sequentially formed on the surface of the conductive substrate, wherein: Except for the process of forming the hole transport layer and the active layer, thermal annealing is not required in other steps.

Images