Oligomeric receptor containing bithiazole spacer and preparation method and application thereof

Abstract

The invention provides a bithiazole spacer-containing oligomeric receptor as well as a preparation method and application thereof. The oligomeric receptor is a small molecule receptor which takes bithiazole as a bridging spacer and is externally connected with a benzothiadiazole (BTP) unit or a quinoxaline (Qx) unit or a phenazine (Pz) unit as a central core. The oligomeric acceptor containing the bithiazole spacer has relatively good light capturing capability, proper electron energy level and relatively strong molecular accumulation; and when being applied to organic solar cells as an electron acceptor material, the compound has relatively high photoelectric conversion efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of organic solar cell materials, and in particular to an oligomeric receptor containing a bithiazole spacer, and a preparation method and application thereof. Background Art

[0002] Organic solar cells (OSCs) with conjugated organic semiconductors as active layers have unique advantages over inorganic photovoltaic cells, such as light weight, semi-transparency and flexibility, which make them have broad application prospects in the fields of wearable and portable electronic devices for future processing (J. Park, G. Kim, S. Lee, J. Lee, S. Li, J. Lee and B. Kim, Adv. Mater., 2022, 34, 2201623; J. Huang, Z. Lu, J. He, H. Hu, Q. Liang, K. Liu, Z. Ren, Y. Zhang, H. Yu, Z. Zheng and G. Li, Energy Environ. Sci., 2023, 16, 1251-1263; L. Zhu, M. Zhang, J. Xu, C. Li, J. Yan, G. Zhou, W. Zhong, T. Hao, J. Song, X. Xue, Z. Zhou, R. Zeng, H. Zhu, C. Chen, R. MacKenzie, Y. Zou, J. Nelson, Y. Zhang, Y. Sun and F. Liu, Nat. Mater., 2022, 21, 656-663.). In recent years, with the continuous development of new high-efficiency donor and acceptor materials, the power conversion efficiency (PCE) of organic solar cells has exceeded 20%, reaching the threshold of commercial application (J.Wu, G.Li, J.Fang, X.Guo, L.Zhu, B.Guo, Y.Wang, G.Zhang, L.Arunagiri, F.Liu, H.Yan, M.Zhang and Y.Li, Nat. Commun., 2020, 11, 4612; X.Guo, Q.Fan, J.Wu, G.Li, Z.Peng, W.Su, J.Lin, L.Hou, Y.Qin, H.Ade, L.Ye, M.Zhang and Y.Li, Nat. Commun., 2020, 11, 4612; X.Guo, Q.Fan, J.Wu, G.Li, Z.Peng, W.Su, J.Lin, L.Hou, Y.Qin, H.Ade, L.Ye, M.Zhang and Y. Li, Angew. Chem. Int. Ed., 2021, 133, 2352-2359; J. Yuan, Y. Zhang, L. Zhou, G. Zhang, H. Yip, TK. Lau, X. Lu, C. Zhu, H. Peng, Paul A. Johnson, M. Leclerc, Y. Cao, J. Ulanski, Y. Li, and Y. Zou, Joule, 2019, 3, 1; M. Zhang, X. Guo, W. Ma, H. Ade and J. Hou, Adv. Mater., 2015, 27, 4655.). However, in order to ensure the commercial viability of OSCs, both high PCE and long device stability need to be met. However, the long-term stability of organic solar cells is an important factor restricting their practical application.

[0003] The current high-performance OSC active layer is a metastable structure formed by a blend of a polymer donor and a non-fullerene small molecule acceptor; among them, the non-fullerene small molecule acceptor, due to its small molecular size, will diffuse rapidly under external stress (such as light and heat), resulting in an unfavorable evolution of its metastable morphology, and then leading to performance degradation (M. Ghasemi, N. Balar, Z. Peng, H. Hu, Y. Qin, T. Kim, J. Rech, M. Bidwell, W. Mask, I. McCulloch, W. You, A. Amassian, C. Risko, B. T. O'Connor and H. Ade, Nat. Mater., 2021, 20, 525-532; Y. Qin, N. Balar, Z. Peng, A. Gadisa, I. Angunawela, A. Bagui, S. Kashani, J. Hou and H. Ade, Joule, 2021, 5, 2129-2147.). He Feng's group oligomerized non-fullerene small molecule receptors for the first time and demonstrated the advantages of OSCs based on oligomeric receptors in terms of PCE and stability. Oligomeric receptors with discrete chain lengths can be highly crystallized, resulting in good optoelectronic properties and high PCE; and oligomeric receptors with extended chain lengths significantly reduce diffusion kinetics, resulting in higher device stability under light and thermal stress (H. Wang, C. Cao, H. Chen, H. Lai, C. Ke, Y. Zhu, H. Li and F. He, Angew. Chem., Int. Ed., 2022, 61, e202201844.). The molecular design of oligomeric receptors is mainly divided into three parts: (1) the conjugated skeleton of the non-fullerene receptor; (2) the length and structure of the side chain; and (3) the position and structure of the spacer. Among them, the position and structure of the spacer play an important role in the photophysical and chemical properties of the material and the device performance.The researchers fine-tuned the molecular conformation, solubility, crystallinity and intermolecular interactions of the oligomeric receptors by adjusting the structure and connection position of the oligomeric receptor spacers, and then optimized the phase separation of the active layer to achieve a significant improvement in the photovoltaic performance of OSCs (Y. Bai, Z. Zhang, Q. Zhou, H. Geng, Q. Chen, S. Kim, R. Zhang, C. Zhang, B. Chang, S. Li, H. Fu, L. Xue, H. Wang, W. Li, W. Chen, M. Gao, L. Ye, Y. Zhou, Y. Ouyang, C. Zhang, F. Gao, C. Yang, Y. Li and Z. Zhang, Nat. Commun., 2023, 14, 2926; C. Sun, J. Lee, C. Lee, D. Lee, S. Cho, S. Kwon, B. Kim and Y. Kim, Joule, 2023, 7, 416-430.). However, the current research on oligomeric receptor spacers mainly focuses on their electron-donating properties and non-covalent conformational locks, while there is a lack of research on the effects of the spacers themselves on molecular stacking. Therefore, it is of great significance to develop an efficient oligomeric receptor containing a new type of spacer and explore its effects on multi-scale molecular stacking. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides an oligomeric acceptor containing a bithiazole spacer, a preparation method thereof and an application thereof. The oligomeric acceptor containing a bithiazole spacer of the present invention has good light capture ability, suitable electronic energy level and strong molecular stacking; it is applied as an electron acceptor material in an organic solar cell and has a high photoelectric conversion efficiency.

[0005] The technical solution of the present invention is as follows:

[0006] An oligomeric receptor containing a bithiazole spacer, wherein the oligomeric receptor is a small molecule receptor with a benzothiadiazole (BTP) unit, a quinoxaline (Qx) unit, or a phenazine (Pz) unit as a central core and has a structure shown in the following formula I, II, or III:

[0007]

[0008] Wherein, in Formula I, Formula II or Formula III,

[0009] R1 is selected from hydrogen, C1~C 30 Alkyl, C1~C 30 Alkoxy, C1~C 30 Alkylthio, One of; wherein R3 is C1~C30 Any one of the alkyl groups;

[0010] R2 is selected from hydrogen, C1~C 30 Alkyl, C1~C 30 Alkoxy or C1~C 30 Any one of the alkylthio groups;

[0011] The electron withdrawing group A is selected from one of the following structures:

[0012]

[0013] The electron withdrawing group B is selected from one of the following structures:

[0014]

[0015] Wherein, R4 is any one of C1 to C8 alkyl groups;

[0016] The bridging spacer C is selected from one of the following structures:

[0017]

[0018] Among them, R5 is C1~C 10 Any one of the alkyl groups.

[0019] Preferably, according to the present invention, the oligomeric receptor containing a bithiazole spacer has a structure as shown in the following formula I-1:

[0020]

[0021] The method for preparing the above-mentioned oligomeric receptor containing a bithiazole spacer comprises the steps of:

[0022] (1) In anhydrous tetrahydrofuran solvent, under the action of n-butyl lithium (n-BuLi), compound 1 and tributyltin chloride are reacted to obtain compound 2;

[0023]

[0024] Wherein, the substituent R1 is the same as R1 in Formula Ⅰ, Formula Ⅱ or Formula Ⅲ;

[0025] (2) Compound 2 and Compound 3 are reacted in toluene under the catalysis of tetrakis(triphenylphosphine)palladium to obtain Compound 4;

[0026]

[0027] (3) Compound 4 is reacted in o-dichlorobenzene under the catalysis of triphenylphosphine to obtain an intermediate; then, in DMF solvent, under the action of K2CO3 and KI, compound R2X and the intermediate are reacted to obtain compound 5;

[0028] In the compound R2X, the substituent X is bromine or iodine, and the substituent R2 is selected from any one of hydrogen, C1-C30 alkyl, C1-C30 alkoxy, or C1-C30 alkylthio;

[0029] (4) POCl3 is fully dispersed in DMF, and a 1,2-dichloroethane solution of compound 5 is added to obtain compound 6 through reaction;

[0030] (5) Compound 6 and Compound A react in toluene in the presence of acetic anhydride and boron trifluoride ether to obtain Compound 7;

[0031] Wherein, compound A is selected from one of the following;

[0032]

[0033] (6) POCl3 was fully dispersed in DMF, and a 1,2-dichloroethane solution of compound 7 was added to obtain compound 8 through reaction;

[0034] (7) Compound 8 and compound B are reacted in toluene in the presence of acetic anhydride and boron trifluoride ether to obtain compound 9;

[0035] Wherein, compound B is selected from one of the following:

[0036]

[0037] Wherein, R4 is any one of C1 to C8 alkyl groups;

[0038] (8) Compound 9 and Compound C are reacted in toluene under the action of tetrakis(triphenylphosphine)palladium to obtain an oligomeric receptor containing a bithiazole spacer;

[0039] The compound C is selected from one of the following:

[0040]

[0041] Among them, R5 is C1~C 10 Any one of the alkyl groups.

[0042] Preferably according to the present invention, Compound 1, Compound 2, Compound 3, Compound 4, Compound 5, Compound 6, Compound 7, Compound 8, and Compound 9 have the following structures respectively:

[0043]

[0044] Preferably according to the present invention, compound R2X is 1-bromo-2-octyldodecane, compound A is 2-(5-bromo-3-oxo-2,3-dihydro-1H-indene-1-ylidene)malononitrile, compound B is 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-1-ylidene)malononitrile, and compound C is 4,4'-dinonyl-5,5'-di(thiophene-2-yl)-2,2'-bithiazole.

[0045] Preferably, in step (1), the volume ratio of the molar amount of compound 1 to anhydrous tetrahydrofuran is 0.1-1 mol / L; the molar ratio of n-butyl lithium (n-BuLi), tributyltin chloride and compound 1 is 1-1.07:1-1.1:1; the reaction conditions are: after reacting at -78°C for 0.5-2 hours, reacting at room temperature for 20-24 hours, and the reaction is carried out under stirring conditions.

[0046] Preferably, in step (1), the post-treatment step of the reaction solution obtained by the reaction is as follows: deionized water is added to the reaction solution to quench the reaction, the organic phase is extracted with ethyl acetate, and the organic phase is decompressed to remove the solvent to obtain compound 2.

[0047] Preferably according to the present invention, in step (2), the volume ratio of the molar amount of compound 3 and toluene is 0.05-1 mol / L; the molar ratio of tetrakis(triphenylphosphine)palladium, compound 1 in step (1) and compound 3 is 0.01-0.1:2.3-2.7:1; the reaction temperature is 100-120°C, the reaction time is 10-15h, and the reaction is carried out under reflux stirring conditions.

[0048] Preferably, in step (2), the post-treatment step of the reaction solution obtained by the reaction is as follows: the reaction solution is extracted with dichloromethane, and the organic phase is purified by column chromatography to obtain compound 4.

[0049] Preferably, in step (3), the volume ratio of the molar amount of compound 3 in step (2) to o-dichlorobenzene is 0.01-0.1 mol / L; the molar ratio of triphenylphosphine to compound 3 in step (2) is 6-10:1; the reaction temperature of compound 4 is 150-200°C, the reaction time is 10-15h, and the reaction is carried out under stirring conditions; the reaction solution obtained by the reaction of compound 4 is subjected to solvent removal to obtain an intermediate.

[0050] Preferably, in step (3), the volume ratio of the molar amount of compound 3 in step (2) to DMF is 0.03-0.5 mol / L; the molar ratio of K2CO3, KI, compound R2X and compound 3 in step (2) is 10-24:10-24:10-24:1; the temperature for the reaction of compound R2X and the intermediate is 60-100°C, the reaction time is 10-14h, and the reaction is carried out under stirring; the reaction solution obtained by the reaction is extracted with dichloromethane, and the organic phase is purified by column chromatography to obtain compound 5.

[0051] Preferably, in step (4), the concentration of the 1,2-dichloroethane solution of compound 5 is 0.02-0.5 mol / L; the molar ratio of POCl3 to the compound 3 in step (2) is 0.7-0.9:1; the volume ratio of the 1,2-dichloroethane solution of compound 5 to DMF is 15-25:1; the reaction temperature is -5-5°C, the reaction time is 4-8h, and the reaction is carried out under stirring; the reaction solution obtained by the reaction is extracted with dichloromethane, and the organic phase is purified by column chromatography to obtain compound 6.

[0052] Preferably, in step (5), the volume ratio of the molar amount of the compound 3 in step (2) to toluene is 0.01-0.5 mol / L; the molar ratio of acetic anhydride, boron trifluoride etherate and the compound 3 in step (2) is 0.2-0.4:2-4:1; the molar ratio of the compound 3 in step (2) to compound A is 1.6-1.8:1; the reaction temperature is 40-80°C, the reaction time is 5-15min, and the reaction is carried out under stirring; the reaction solution obtained by the reaction is added to methanol, the precipitate is filtered out, the precipitate is dissolved in dichloroethane solvent, and purified by column chromatography to obtain compound 7.

[0053] Preferably, in step (6), the concentration of the 1,2-dichloroethane solution of compound 7 is 0.02-0.5 mol / L; the molar ratio of POCl3 to the compound 3 in step (2) is 0.7-0.9:1; the volume ratio of the 1,2-dichloroethane solution of compound 7 to DMF is 15-25:1; the reaction temperature is -5-5°C, the reaction time is 4-8h, and the reaction is carried out under stirring; the reaction solution obtained by the reaction is extracted with dichloromethane, and the organic phase is purified by column chromatography to obtain compound 8.

[0054] Preferably, in step (7), the volume ratio of the molar amount of compound 3 in step (2) to toluene is 0.01-0.5 mol / L; the molar ratio of acetic anhydride, boron trifluoride etherate and compound 3 in step (2) is 0.1-0.3:1-3:1; the molar ratio of compound 3 in step (2) to compound B is 2-2.4:1; the reaction temperature is 40-80°C, the reaction time is 5-15min, and the reaction is carried out under stirring; the reaction solution obtained by the reaction is added to methanol, the precipitate is filtered, the precipitate is dissolved in dichloromethane solvent, and purified by column chromatography to obtain compound 9.

[0055] Preferably, in step (8), the volume ratio of the molar amount of compound C to toluene is 0.02-0.5 mol / L; the molar ratio of tetrakis(triphenylphosphine)palladium, compound 3 in step (2) and compound C is 0.005-0.05:1:0.1-0.3; the reaction temperature is 100-120°C, the reaction time is 10-20h, and the reaction is carried out under stirring; the reaction solution obtained by the reaction is added to methanol for precipitation, the precipitate is collected and dissolved in chloroform, and purified by column chromatography to obtain an oligomeric receptor containing a bithiazole spacer.

[0056] The above oligomeric acceptor containing bithiazole spacer is used as an electron acceptor material of a photon capture active layer in an organic solar cell.

[0057] According to the preferred embodiment of the present invention, the solar cell comprises, from bottom to top, an indium tin oxide substrate, a PEDOT:PSS layer, an active layer, a PDINN layer, and an Ag layer; wherein the active layer is composed of an oligomeric acceptor containing a bithiazole spacer and a donor material, and the mass ratio of the oligomeric acceptor containing a bithiazole spacer to the donor material is 1-1.5:1; the donor material is PBDB-TF, and has the following structure:

[0058]

[0059] The preparation route of the oligomeric receptor containing a bithiazole spacer represented by formula I of the present invention is as follows:

[0060]

[0061] The technical features and beneficial effects of the present invention are as follows:

[0062] 1. The oligomeric receptor containing a bithiazole spacer group of the present invention can be processed by a solution method, can be dissolved in organic solvents such as chloroform and chlorobenzene, and has good film-forming properties.

[0063] 2. The present invention contains an oligomeric receptor containing a bithiazole spacer, which uses bithiazole as a bridging spacer, and is externally connected to an A-DA'DA type small molecule receptor with a benzothiadiazole (BTP) unit or a quinoxaline (Qx) unit or a phenazine (Pz) unit as a central core, and a series of new, well-soluble, and thermally stable conjugated molecules with bithiazole and its derivatives as spacers are designed and synthesized. The introduction of bithiazole spacers enhances intermolecular interactions and helps to improve molecular stacking and crystallinity. Secondly, the introduction of S...N non-covalent interactions is conducive to reducing the torsion angle between the monomer and the spacer and enhancing the planarity of the main chain conformation. In addition, bithiazole and its derivatives have weak electron-withdrawing properties and can appropriately adjust the energy level. Therefore, this type of molecule has strong visible light absorption ability, good light capture ability, suitable electronic energy level and strong molecular stacking, and is suitable for use as an electron acceptor material in the preparation of organic solar cells; the oligomeric receptor of the present invention is applied to organic solar cells with high photoelectric conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 The UV-visible-near infrared absorption spectra of the oligomeric receptor containing a bithiazole spacer prepared in Example 1 in the thin film and solution states;

[0065] Figure 2 The cyclic voltammetry curve of the oligomeric receptor containing a bithiazole spacer prepared in Example 1;

[0066] Figure 3 This is the JV curve of the oligomeric acceptor containing a bithiazole spacer prepared in Example 1 when applied to an organic solar cell. DETAILED DESCRIPTION

[0067] In order 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 in conjunction with the accompanying drawings and embodiments. However, the present invention is not limited to the embodiments listed, and should also include any other known changes within the scope of the rights claimed by the present invention.

[0068] Example 1

[0069] A synthetic route of an oligomeric receptor DY-Tz containing a bithiazole spacer is as follows:

[0070]

[0071] The synthesis steps are as follows:

[0072] Step 1) synthesizing compound 2;

[0073] Under argon protection, compound 1, i.e. 3-undecylthieno[3,2-B]thiophene (5 g, 16.98 mmol), was dissolved in 120 mL of anhydrous tetrahydrofuran, and n-butyllithium (7.07 mL, 16.98 mmol) was slowly added in an acetone liquid nitrogen bath (-78 ° C). After stirring for 2 hours, tributyltin chloride (5.53 g, 16.98 mmol) was added. After stirring at -78 ° C for 1 hour, the reaction was stirred at room temperature for 24 hours, and deionized water was added to quench the reaction. The organic phase was extracted with ethyl acetate, and the solvent was removed under reduced pressure to obtain compound 2.

[0074] Step 2) synthesizing compound 4;

[0075] Under argon protection, compound 2, compound 3 (4,7-dibromo-5,6-dinitrobenzo[c][1,2,5]thiadiazole) (2.6 g, 6.8 mmol) and tetrakis(triphenylphosphine)palladium (230 mg, 0.33 mmol) were stirred and refluxed at 110°C in 80 mL of toluene for 12 hours, the reaction mixture was restored to room temperature, extracted with dichloromethane, and the organic phase was purified by column chromatography to obtain compound 4.

[0076] Step 3) synthesizing compound 5;

[0077] Under argon protection, compound 4 and triphenylphosphine (PPh3) (14.4 g, 55 mmol) were stirred in 10 mL o-dichlorobenzene at 180 ° C for 12 hours, and the reaction solution was dried by rotary evaporation while hot. After removing the solvent, compound 1-bromo-2-octyldodecane (39.7 g, 110 mmol), K2CO3 (15.5 g, 110 mmol) and KI (18.3 g, 110 mmol) were added, stirred in 40 mL DMF solvent at 80 ° C for 12 hours, extracted with dichloromethane, and the organic phase was purified by column chromatography to obtain compound 5.

[0078] Step 4) synthesizing compound 6;

[0079] Under argon protection, POCl3 (0.9 g, 5.9 mmol) was slowly injected into 1.5 mL DMF at 0°C. After stirring for 2 hours, 30 mL of compound 5 dissolved in 1,2-dichloroethane was added. After stirring for 6 hours, the mixture was extracted with dichloromethane. The organic phase was purified by column chromatography to obtain compound 6.

[0080] Step 5) synthesizing compound 7;

[0081] Under argon protection, compound 6, 2-(5-bromo-3-oxo-2,3-dihydro-1H-inden-1-yl)malononitrile (1.1 g, 3.9 mmol), acetic anhydride (2 mmol) and boron trifluoride etherate (20 mmol) were stirred in 50 mL of anhydrous toluene solution at 60°C for 10 minutes, cooled to room temperature, and the reaction solution was slowly added to methanol. The precipitate was collected by filtration and dissolved in dichloromethane. The compound 7 was purified by column chromatography.

[0082] Step 6) synthesizing compound 8;

[0083] Under argon protection, POCl3 (0.83 g, 5.4 mmol) was slowly injected into 1.2 mL of DMF at 0°C. After stirring for 2 hours, 25 mL of compound 7 dissolved in 1,2-dichloroethane was added. After stirring for 6 hours, the mixture was extracted with dichloromethane. The organic phase was purified by column chromatography to obtain compound 8.

[0084] Step 7) synthesizing compound 9;

[0085] Under argon protection, compound 8, 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-yl)malononitrile (0.7 g, 3 mmol), acetic anhydride (1.2 mmol) and boron trifluoride etherate (15 mmol) were stirred in 45 mL of anhydrous toluene solution at 60°C for 10 minutes, cooled to room temperature, and the reaction solution was slowly added to methanol. The precipitate was filtered and dissolved in dichloromethane and purified by column chromatography to obtain compound 9.

[0086] Step 8) synthesizing the oligomeric receptor DY-Tz;

[0087] Under argon protection, compound 9, 4,4'-dinonyl-5,5'-di(thiophen-2-yl)-2,2'-bithiazole (0.75 g, 0.82 mmol) and tetrakis(triphenylphosphine)palladium (0.08 mmol) were stirred in 5 mL of toluene at 110 °C for 12 h. The reaction solution was cooled to room temperature and slowly added to methanol for precipitation. The precipitate was collected and dissolved in chloroform and purified by column chromatography to obtain an oligomeric receptor containing a bithiazole spacer.

[0088] The NMR data of the product are as follows:

[0089] 1H NMR(300MHz,Chloroform-d)δ9.19(s,2H),9.14(s,2H),8.81(dd,2H),8.62-8.57(m,2H),8.04(m,2H),7.94(m,2H),7.73(s,2H),7.5 6(s,2H),7.32(s,2H),4.81(s,8H),3.22(s,4H),3.05(s,8H),2.03(s,8H),1.36-0.84(m,274H).MS(MALDI-TOF)m / z:[MH]calculated for C 248 H 320 F4N 18 O4S 14 ,found:4139.49.

[0090] UV-Vis-NIR absorption spectrum test: The absorption spectrum of the material was tested by SHIMADZU UV-1900i Spectrophotometer from Japan. The absorption sample of the film was a 10 mg / mL chloroform solution of the oligomeric receptor that was spin-coated on a quartz plate at 3000 rpm. The absorption spectrum of the solution was determined by using chloroform as the solvent and preparing the oligomeric receptor material into 1×10 -5 mol L -1 Solution. Figure 1 As shown, there is strong absorption in the range of 600-850nm, and the film absorption has a maximum absorption peak at 785nm, indicating that it has good light capture ability.

[0091] The energy level of the material was measured by cyclic voltammetry using an Admiral Squidstat Plus electrochemical workstation. -1 The acetonitrile solution of Bu4NPF6 was used as the electrolyte solution, and the platinum wire electrode, glassy carbon electrode and Ag / Ag+ electrode were used as the auxiliary electrode, working electrode and reference electrode respectively. The reference electrode was calibrated by the redox potential of ferrocene (Fc / Fc+). Figure 2 As shown, the initial oxidation potential (φ ox ) is 0.97eV vs Ag / Ag + , initial reduction potential (φ re ) is -0.93eV vs Ag / Ag + . By the formula HOMO = -(E ox +4.70)(eV) and LUMO=-(E re+4.70)(eV) It can be calculated that the HOMO energy level and LUMO energy level of DY-Tz are -5.67eV and -3.77eV respectively; which can match the efficient polymer donor.

[0092] Test example

[0093] Preparation and performance testing of solar photovoltaic devices:

[0094] The commercially purchased indium tin oxide (ITO) glass was first scrubbed with acetone, and then ultrasonically cleaned with detergent, water, deionized water, acetone, and isopropanol in sequence. After drying, a 30nm thick PEDOT:PSS layer was spin-coated as an anode modification layer for standby use. A chloroform blend solution of the polymer donor material PBDB-TF, the oligomeric acceptor containing a bithiazole spacer prepared in Example 1 (weight ratio of 1:1.2) and the additive chloronaphthalene (accounting for 0.75vt% of the volume of chloroform) (wherein the concentration of the oligomeric acceptor containing a bithiazole spacer prepared in Example 1 is 9.6mg / mL) was spin-coated on the PEDOT:PSS anode modification layer to form the active layer (105nm) of the device. Finally, a layer of PDINN with a thickness of about 10nm was spin-coated as a cathode modification layer and Ag (100nm) as the device cathode to obtain a solar cell device. The effective area of ​​the photovoltaic device is 0.049cm 2 The energy conversion efficiency of solar cells was measured using LSS-55 (LightSky Technology CO., Ltd.) as a solar simulator at 100 mW / cm 2 The photovoltaic performance of the device was tested under light intensity, and the light intensity was calibrated by a standard single-crystal silicon solar cell (LST-QE); the JV curve was measured using Keithley 2400. The test obtained the three parameters of the solar cell device: open circuit voltage, short circuit current, and fill factor.

[0095] Its JV curve is shown in Figure 3 , where the open circuit voltage of the polymer solar cell device is V OC =0.97V, short circuit current J SC =21.4mA / cm 2 , filling factor FF = 65.8%, conversion efficiency PCE = 13.7%.

[0096] The structure of the polymer donor PBDB-TF used above is as follows (it can be prepared by referring to the method of “M. Zhang, X. Guo, W. Ma, H. Ade and J. Hou, Adv. Mater., 2015, 27, 4655.”):

[0097]

[0098] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An oligomeric receptor containing a bithiazole spacer, characterized in that: The oligomeric receptor is a small molecule receptor with a benzothiadiazole (BTP) unit, a quinoxaline (Qx) unit or a phenazine (Pz) unit as a central core, and has a structure shown in the following formula I, II or III: Wherein, in Formula I, Formula II or Formula III, R1 is selected from hydrogen, C1~C 30 Alkyl, C1~C 30 Alkoxy, C1~C 30 Alkylthio, One of; wherein R3 is C1~C 30 Any one of the alkyl groups; R2 is selected from hydrogen, C1~C 30 Alkyl, C1~C 30 Alkoxy or C1~C 30 Any one of the alkylthio groups; The electron withdrawing group A is selected from one of the following structures: The electron withdrawing group B is selected from one of the following structures: Wherein, R4 is any one of C1 to C8 alkyl groups; The bridging spacer C is selected from one of the following structures: Among them, R5 is C1~C 10 Any one of the alkyl groups.

2. The oligomeric receptor containing a bithiazole spacer according to claim 1, characterized in that: The oligomeric receptor containing a bithiazole spacer has a structure as shown in the following formula I-1:

3. The method for preparing the oligomeric receptor containing a bithiazole spacer as claimed in claim 1 or 2, comprising the steps of: (1) In anhydrous tetrahydrofuran solvent, under the action of n-butyl lithium (n-BuLi), compound 1 and tributyltin chloride are reacted to obtain compound 2; in, The substituent R1 is the same as R1 in Formula Ⅰ, Formula Ⅱ or Formula Ⅲ; (2) Compound 2 and Compound 3 are reacted in toluene under the catalysis of tetrakis(triphenylphosphine)palladium to obtain Compound 4; (3) Compound 4 is reacted in o-dichlorobenzene under the catalysis of triphenylphosphine to obtain an intermediate; then, in DMF solvent, under the action of K2CO3 and KI, compound R2X and the intermediate are reacted to obtain compound 5; In the compound R2X, the substituent X is bromine or iodine, and the substituent R2 is selected from any one of hydrogen, C1-C30 alkyl, C1-C30 alkoxy, or C1-C30 alkylthio; (4) POCl3 is fully dispersed in DMF, and a 1,2-dichloroethane solution of compound 5 is added to obtain compound 6 through reaction; (5) Compound 6 and Compound A react in toluene in the presence of acetic anhydride and boron trifluoride ether to obtain Compound 7; Wherein, compound A is selected from one of the following; (6) POCl3 was fully dispersed in DMF, and a 1,2-dichloroethane solution of compound 7 was added to obtain compound 8 through reaction; (7) Compound 8 and compound B are reacted in toluene in the presence of acetic anhydride and boron trifluoride ether to obtain compound 9; Wherein, compound B is selected from one of the following: Wherein, R4 is any one of C1 to C8 alkyl groups; (8) Compound 9 and Compound C are reacted in toluene under the action of tetrakis(triphenylphosphine)palladium to obtain an oligomeric receptor containing a bithiazole spacer; The compound C is selected from one of the following: Among them, R5 is C1~C 10 Any one of the alkyl groups.

4. The method for preparing an oligomeric receptor containing a bithiazole spacer according to claim 3, characterized in that: Compound 1, Compound 2, Compound 3, Compound 4, Compound 5, Compound 6, Compound 7, Compound 8, and Compound 9 respectively have the following structures:

5. The method for preparing an oligomeric receptor containing a bithiazole spacer according to claim 3, characterized in that: Compound R2X is 1-bromo-2-octyldodecane, compound A is 2-(5-bromo-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile, compound B is 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile, and compound C is 4,4'-dinonyl-5,5'-di(thiophen-2-yl)-2,2'-bithiazole.

6. The method for preparing an oligomeric receptor containing a bithiazole spacer according to claim 3, characterized in that: Includes one or more of the following conditions: i. In step (1), the volume ratio of the molar amount of compound 1 to anhydrous tetrahydrofuran is 0.1-1 mol / L; the molar ratio of n-butyl lithium (n-BuLi), tributyltin chloride and compound 1 is 1-1.07:1-1.1:1; the reaction conditions are: react at -78°C for 0.5-2 hours, then react at room temperature for 20-24 hours, and the reaction is carried out under stirring; ii. In step (2), the volume ratio of the molar amount of compound 3 to toluene is 0.05-1 mol / L; the molar ratio of tetrakis(triphenylphosphine)palladium, compound 1 in step (1) and compound 3 is 0.01-0.1:2.3-2.7:1; the reaction temperature is 100-120° C., the reaction time is 10-15 h, and the reaction is carried out under reflux stirring conditions; iii. In step (3), the volume ratio of the molar amount of compound 3 in step (2) to o-dichlorobenzene is 0.01-0.1 mol / L; the molar ratio of triphenylphosphine to compound 3 in step (2) is 6-10:1; the reaction temperature of compound 4 is 150-200°C, the reaction time is 10-15h, and the reaction is carried out under stirring; the reaction solution obtained by the reaction of compound 4 is subjected to solvent removal to obtain an intermediate; iv. In step (3), the volume ratio of the molar amount of the compound 3 in step (2) to DMF is 0.03-0.5 mol / L; the molar ratio of K2CO3, KI, compound R2X and the compound 3 in step (2) is 10-24:10-24:10-24:1; the temperature for the reaction of compound R2X and the intermediate is 60-100°C, the reaction time is 10-14h, and the reaction is carried out under stirring; the reaction solution obtained by the reaction is extracted with dichloromethane, and the organic phase is purified by column chromatography to obtain compound 5; v. In step (4), the concentration of the 1,2-dichloroethane solution of compound 5 is 0.02-0.5 mol / L; the molar ratio of POCl3 to the compound 3 in step (2) is 0.7-0.9:1; the volume ratio of the 1,2-dichloroethane solution of compound 5 to DMF is 15-25:1; the reaction temperature is -5-5°C, the reaction time is 4-8h, and the reaction is carried out under stirring; the reaction solution obtained by the reaction is extracted with dichloromethane, and the organic phase is purified by column chromatography to obtain compound 6; vi. In step (5), the volume ratio of the molar amount of the compound 3 in step (2) to toluene is 0.01-0.5 mol / L; the molar ratio of acetic anhydride, boron trifluoride etherate and the compound 3 in step (2) is 0.2-0.4:2-4:1; the molar ratio of the compound 3 in step (2) to compound A is 1.6-1.8:1; the reaction temperature is 40-80°C, the reaction time is 5-15 min, and the reaction is carried out under stirring; the reaction solution obtained by the reaction is added to methanol, the precipitate is filtered, the precipitate is dissolved in dichloroethane solvent, and purified by column chromatography to obtain compound 7; vii. In step (6), the concentration of the 1,2-dichloroethane solution of compound 7 is 0.02-0.5 mol / L; the molar ratio of POCl3 to the compound 3 in step (2) is 0.7-0.9:1; the volume ratio of the 1,2-dichloroethane solution of compound 7 to DMF is 15-25:1; the reaction temperature is -5-5°C, the reaction time is 4-8h, and the reaction is carried out under stirring; the reaction solution obtained by the reaction is extracted with dichloromethane, and the organic phase is purified by column chromatography to obtain compound 8; viii. In step (7), the volume ratio of the molar amount of the compound 3 in step (2) to toluene is 0.01-0.5 mol / L; the molar ratio of acetic anhydride, boron trifluoride etherate and the compound 3 in step (2) is 0.1-0.3:1-3:1; the molar ratio of the compound 3 in step (2) to compound B is 2-2.4:1; the reaction temperature is 40-80°C, the reaction time is 5-15 min, and the reaction is carried out under stirring; the reaction solution obtained by the reaction is added to methanol, the precipitate is filtered, the precipitate is dissolved in dichloromethane solvent, and purified by column chromatography to obtain compound 9; ix. In step (8), the molar ratio of compound C to toluene is 0.02-0.5 mol / L; the molar ratio of tetrakis(triphenylphosphine)palladium, compound 3 in step (2) and compound C is 0.005-0.05:1:0.1-0.3; the reaction temperature is 100-120°C, the reaction time is 10-20h, and the reaction is carried out under stirring; the reaction solution obtained by the reaction is added to methanol for precipitation, the precipitate is collected and dissolved in chloroform, and purified by column chromatography to obtain an oligomeric receptor containing a bithiazole spacer.

7. The use of the oligomeric receptor containing a bithiazole spacer as claimed in claim 1 or 2, characterized in that: Electron acceptor materials as photon-harvesting active layers for use in organic solar cells.

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