Bis-triphenylamine benzothiadiazole compound as well as preparation method and application thereof

Abstract

The specific preparation process comprises the following steps: dissolving a compound as shown in a formula (II) and cyanoacetic acid or rhodanine-3-acetic acid in a solvent, adding an alkali catalyst, carrying out heating reflux reaction under stirring, and after the reaction is finished, concentrating to remove the solvent to obtain the bis (triphenylamine) benzothiadiazole compound as shown in the formula (II). The preparation method comprises the following steps: adding benzothiadiazole to two triphenylamine electron donors, dissolving the obtained concentrate in an eluent, carrying out separation and purification through column chromatography silica gel, collecting the eluent, and evaporating to remove the eluent so as to prepare a compound shown in the formula ZR-1 or ZR-4, and using the compound to prepare the dye sensitizer. The bistriphenylamine benzothiadiazole compound is synthesized by introducing an anchoring group and electron acceptor cyanoacetic acid or rhodanine-3-acetic acid on benzothiadiazole, so that a new applicable substance is added for screening of dye sensitizers, and the bistriphenylamine benzothiadiazole compound can be used for preparing the bistriphenylamine benzothiadiazole compound.

Description

Technical Field

[0001] This invention relates to bibis(triphenylamine)benzothiadiazole compounds, their preparation methods, and their application as co-sensitizers in dye-sensitized solar cells. Background Technology

[0002] A solar cell is a photovoltaic device that absorbs sunlight and directly converts it into electrical energy. Currently, solar cells are not only widely used in high-tech fields such as military and aerospace, but also play an increasingly important role in various sectors including industry, commerce, agriculture, communications, home appliances, and public utilities. Among the many types of solar cells, dye-sensitized solar cells have attracted widespread attention due to their simple manufacturing process, low cost, ease of lightweighting, and thin-film fabrication.

[0003] The key structural material in dye-sensitized solar cells (DSSCs) is the dye sensitizer, whose visible light absorption efficiency ultimately affects the photoelectric conversion efficiency. Therefore, structural modification of dye sensitizers to improve their molar absorptivity, increase their visible light absorption efficiency, and broaden their absorption range is the main direction of dye sensitizer development. When the absorption spectral response range of a single dye is narrow, and broadening the absorption spectrum encounters a bottleneck, co-sensitization processes utilizing the complementary light absorption strategy of dye molecules have emerged. Co-sensitizing two dyes and assembling them into DSSCs is expected to expand the absorption spectral range of DSSCs, increase the photocurrent of the cell, and thus increase the photoelectric conversion efficiency of the cell. Summary of the Invention

[0004] To address the aforementioned problems in existing technologies, the present invention aims to provide a bis(triphenylamine)benzothiadiazole compound, its preparation method, and its application as a co-sensitizer in dye-sensitized solar cells. The bis(triphenylamine)benzothiadiazole compound can be co-sensitized with the metal dye sensitizer Z907, and the assembled dye-sensitized solar cell exhibits good photoelectric conversion efficiency, adding a new applicable material to the screening of co-sensitizers for dye sensitizer Z907.

[0005] This invention discloses bibis(triphenylamine)benzothiadiazole compounds, including compounds with the following two structures, the molecular structures of which are shown in formula (ZR-1) or formula (ZR-4): .

[0006] The present invention also discloses a method for preparing the bibis(triphenylamine)benzothiadiazole compounds ZR-1 and ZR-4. Specifically, the compound shown in formula (II) and cyanoacetic acid or rhodanine-3-acetic acid are dissolved in a solvent, an alkaline catalyst is added, and the mixture is heated under reflux with stirring. After the reaction is completed, the solvent is removed by concentration, and the resulting concentrate is dissolved in an eluent and then separated and purified by column chromatography with silica gel. The eluent is collected and the eluent is evaporated to obtain ZR-1 or ZR-4. The structural formula of the compound shown in formula (II) is as follows: .

[0007] Furthermore, the present invention also discloses that the alkaline catalyst is piperidine.

[0008] Furthermore, the present invention also discloses the compound shown in formula (II): the molar ratio of the catalyst is 1:6.7-10.

[0009] Furthermore, the present invention also discloses that the reaction time is 10-12 h.

[0010] Furthermore, the present invention also discloses a mixed solvent of acetonitrile and chloroform, wherein the volume ratio of acetonitrile to chloroform is 2:1.

[0011] Furthermore, the present invention also discloses that the eluent is a mixed solvent composed of dichloromethane and methanol, wherein the volume ratio of dichloromethane to methanol is 20:1.

[0012] Furthermore, the present invention also discloses that the molar ratio of formula (II) to cyanoacetic acid or rhodanine-3-acetic acid is 1:5-6.

[0013] Furthermore, the present invention also discloses that the ratio of the amount of substance of the compound shown in formula (II) to the volume of the solvent is 1:40-50, the unit of amount of substance is mmol, and the unit of volume is mL.

[0014] Furthermore, the present invention also discloses a method for synthesizing the compound shown in formula (II), as follows: The compound shown in formula (III), the compound shown in formula (IV), potassium carbonate and tetraphenylphosphine palladium were dissolved in a mixed solvent of tetrahydrofuran and water, heated to reflux, and after the reaction was completed and cooled to room temperature, the mixture was extracted with dichloromethane, washed with saturated brine and dried, the solvent was removed by rotary evaporation and purified by column chromatography to obtain the compound shown in formula (II).

[0015] The structural formulas of the compounds shown in formula (III) and (IV) are as follows: , Furthermore, the present invention also discloses that when synthesizing the compound shown in formula (II), the eluent is petroleum ether and dichloromethane in a volume ratio of 2:1; wherein the column chromatography separation process is as follows: the concentrate is dissolved in the eluent and then separated and purified by column chromatography silica gel, the eluent is collected and the eluent is evaporated, and the product is dried to obtain a solid powder product.

[0016] Furthermore, the present invention also discloses the application of bibis(triphenylamine)benzothiadiazole compounds as dye sensitizers.

[0017] By employing the above-described technology, the beneficial effects of the present invention compared to the prior art are as follows: The core of this invention lies in the symmetrical structure of "triphenylamine (electron donor) - benzothiadiazole (electron withdrawer) - triphenylamine (electron donor)", that is, two strong electron donor triphenylamines are bridged by an electron withdrawer benzothiadiazole to form a symmetrical bis-triphenylamine structure. A strong electron-withdrawing group, cyanoacetic acid or rhodanine-3-acetic acid, is introduced onto the electron withdrawer benzothiadiazole to synthesize two bibis-triphenylamine benzothiadiazole compounds. These bibis-triphenylamine benzothiadiazole compounds can be used as dye sensitizers. The use of Z907 as a co-sensitizer resulted in dye-sensitized solar cells exhibiting excellent photoelectric conversion efficiency, with efficiencies of 5.82% and 5.71%, respectively. These efficiencies are significantly higher than the 5.29% efficiency achieved when Z907 is used alone. This indicates that the compound effectively supplements the light absorption range of the Z907 dye, enabling the utilization of more sunlight and thus improving the current density (Jsc) and final efficiency. This adds a new and applicable material to the screening of dye sensitizers. Detailed Implementation

[0018] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0019] Example 1: Synthesis of the compound shown in formula (ZR-1): , 1) Synthesis of the compound shown in formula (II) Compound III (0.69 g, 2.4 mmol), compound IV (0.20 g, 0.6 mmol), potassium carbonate (0.25 g, 1.8 mmol), and tetra(triphenylphosphine)palladium (0.04 g, 0.03 mmol) were placed in a Shrek flask, dissolved in water (3 mL) and tetrahydrofuran (9 mL), and heated under reflux for 11 h under nitrogen protection. The reaction solution was extracted with DCM, washed with saturated NaCl solution, and dried over anhydrous Na₂SO₄. After the solvent was evaporated to dryness, the residue was separated by column chromatography (V... PE :V DCM = 2 : 1), yielding red solid II (0.30 g, 76.9%).

[0020] Compound shown in formula (II): Melting point: 271-273 °C. 1 H NMR (500 MHz, CDCl3) δ10.25 (s,1H), 8.30 (s, 1H), 7.92 (dd, J= 9.2, 2.3 Hz, 2H), 7.51 (dd, J = 6.5, 4.7 Hz,2H), 7.37-7.31 (m, 8H), 7.26-7.21 (m, 12H), 7.14 (t, J = 7.3 Hz, 2H), 7.10(t, J = 7.3 Hz, 2H). HRMS (ESI) m / z calcd for C 43 H 30 N4OSNa + (M+Na) + 673.2038, found 673.2037. 2) Synthesis of the compound shown in formula (ZR-1) Compound II (0.20 g, 0.3 mmol) and cyanoacetic acid (0.13 g, 1.5 mmol) were added to a Shrek flask, dissolved in acetonitrile (8 mL) and chloroform (4 mL). Then, 0.2 mL of piperidine was slowly added dropwise under nitrogen protection. The reaction was heated to reflux for 10 h until complete. The solvent was removed by rotary evaporation, and the residue was purified by silica gel column chromatography (V...). DCM V MeOH = 20 : 1), yielding a purplish-red solid ZR-1 (0.18 g, 82.0%).

[0021] The compound shown in formula (ZR-1) has a melting point of 281-282 °C. 1 H NMR (500 MHz, DMSO- d 6 ) δ 8.43(s, 1H), 8.16 (s, 1H), 7.97 (d, J = 8.7 Hz, 2H), 7.44 (d, J = 8.6 Hz, 2H),7.41-7.36 (m, 8H), 7.19- 7.09 (m, 14H), 7.04 (d, J = 8.6 Hz, 2H). HRMS (ESI)m / z calcd for C 46 H 31 N5O2SNa + (M+Na) + 740.2096, found 740.2089. Example 2 Synthesis of the compound shown in formula (ZR-4): ,

[0022] Compound II (0.20 g, 0.3 mmol) and rhodanine-3-acetic acid (0.35 g, 1.5 mmol) were added to a Shrek flask, followed by acetonitrile (10 mL) and chloroform (5 mL). After stirring to dissolve, 0.3 mL of piperidine was slowly added dropwise. Under nitrogen protection, the mixture was heated to reflux for 12 h until the reaction was complete. The solvent was removed by rotary evaporation, and the residue was purified by silica gel column chromatography (V). DCM V MeOH = 20 : 1), yielding a purplish-black solid ZR-4 (0.21 g, 88.0%).

[0023] The compound shown in formula (ZR-4) has a melting point of 86-88 °C. 1 H NMR (500 MHz, DMSO- d 6 ) δ 8.00-7.96(m, 3H), 7.88 (s, 1H), 7.51 (d, J = 7.0 Hz, 2H), 7.45-7.27 (m, 9H), 7.22-7.01(m, 15H), 4.74 (s, 2H). HRMS (ESI) m / z calcd for C 48 H 33 N5O3S3Na + (M+Na) + 846.1643, found 846.1634. Example 3: Application of bis(triphenylamine)benzothiadiazole compounds as co-sensitizers for Z907: When used as a dye sensitizer, the application includes the following steps: The bis(triphenylamine)benzothiadiazole compound prepared in Examples 1-2 and dye Z907 were dissolved in a mixed solvent of CH3Cl-CH3OH to obtain a mixed solution of bis(triphenylamine)benzothiadiazole compound and Z907 (concentration 3×10⁻⁶). -4 mol•L -1 The volume ratio of CH3Cl to CH3OH in the CH3Cl-CH3OH mixed solvent is 10:1. A bilayer TiO2 nanoparticle film prepared by screen printing was used as a photoelectrode: First, a 12 μm thick layer of 20 nm TiO2 particles was printed on conductive glass FTO, and then calcined in a muffle furnace at 450 °C for 30 min. After cooling the calcined film to room temperature, it was immersed in 0.04 mol•L⁻¹ water. -1The membrane was pretreated in a TiCl4 aqueous solution at 70 °C for 30 min, then removed from the TiCl4 aqueous solution and rinsed with water and ethanol respectively, and dried with a hair dryer. After being calcined again in a muffle furnace at 450 °C for 30 min, a bilayer TiO2 nanoparticle film photoelectrode was obtained.

[0024] After cooling the bilayer TiO2 nanoparticle film photoelectrode obtained by calcination to 80°C, it was immersed in a mixed solution of the bi-triphenylamine benzothiadiazole compound and Z907 prepared in Examples 1-2, and sensitized at room temperature for 24 h to obtain a TiO2 electrode loaded with bi-triphenylamine benzothiadiazole compound and Z907 compound.

[0025] Preparation of platinum counter electrode: H2PtCl6 aqueous solution was printed onto FTO conductive glass using screen printing. The surface of FTO conductive glass was then wetted with H2PtCl6 aqueous solution, dried, and sintered in a muffle furnace at 400 °C for 20 min to obtain the platinum counter electrode.

[0026] The bilayer TiO2 nanoparticle film photoelectrode and platinum counter electrode prepared above were assembled into a sandwich structure. Electrolyte was dropped into the edge of the sandwich structure and introduced into the battery using capillary permeation, thus assembling a dye-sensitized solar cell (DSSC). A 100 mW / cm² solar cell was then used. 2 Under light intensity irradiation, the current-voltage curves of the DSSC assembled from biphenylamine benzothiadiazole compounds and Z907 were measured, and the performance parameters are shown in Table 1. Table 1 Performance parameters of DSSCs assembled from bi-triphenylamine benzothiadiazole compounds

[0027] As can be seen from Table 1, the dye-sensitized solar cells assembled with the bis(triphenylamine)benzothiadiazole compound and Z907 as dye sensitizers of this invention have good photoelectric conversion efficiency, with photoelectric conversion efficiencies of 5.81% and 5.71%, respectively, both higher than the efficiency of 5.29% of the solar cells sensitized by Z907 alone. This adds a new applicable material to the screening of co-sensitizers of Z907.

[0028] The contents described in this specification are merely an enumeration of the implementation forms of the inventive concept. The scope of protection of this invention should not be regarded as limited to the specific forms described in the embodiments. The scope of protection of this invention is also limited to the equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims

1. A bis(triphenylamine)benzothiadiazole compound, characterized in that... Its molecular structure is shown in formula (ZR-1) or formula (ZR-4): 。 2. A method for preparing the bibis(triphenylamine)benzothiadiazole compound according to claim 1, characterized in that... The compound shown in formula (II) and cyanoacetic acid or rhodanine-3-acetic acid are dissolved in a solvent, stirred and heated under reflux in the presence of an alkaline catalyst, and the solvent is removed after the reaction is completed. The resulting concentrate is dissolved in eluent and then separated and purified by column chromatography with silica gel. The eluent is collected and the eluent is evaporated to obtain the target product, which is the bibis(triphenylamine)benzothiadiazole compound shown in formula (ZR-1) or formula (ZR-4). The structural formula of the compound shown in formula (II) is as follows: 。 3. The method for preparing the bibis(triphenylamine)benzothiadiazole compound according to claim 2, characterized in that... The molar ratio of the compound shown in formula (II) to the base catalyst is 1:6.7-10.

4. The method for preparing the bibis(triphenylamine)benzothiadiazole compound according to claim 2, characterized in that... The alkaline catalyst used is piperidine.

5. The method for preparing the bibis(triphenylamine)benzothiadiazole compound according to claim 2, characterized in that... The reaction time for the reflux heating reaction is 10-12 h.

6. The method for preparing the bibis(triphenylamine)benzothiadiazole compound according to claim 2, characterized in that... The molar ratio of the compound shown in formula (II) to cyanoacetic acid or rhodanine-3-acetic acid is 1:5-6.

7. The method for preparing the bibis(triphenylamine)benzothiadiazole compound according to claim 2, characterized in that... The solvent is a mixture of acetonitrile and chloroform in a volume ratio of 2:1; the ratio of the amount of substance of the compound shown in formula (II) to the volume of the solvent is 1:40-50, the unit of amount of substance is mmol, and the unit of volume is mL.

8. The method for preparing the bibis(triphenylamine)benzothiadiazole compound according to claim 2, characterized in that... The eluent is a mixed solvent consisting of dichloromethane and methanol in a volume ratio of 20:

1.

9. The method for preparing the bibis(triphenylamine)benzothiadiazole compound according to any one of claims 2-8, characterized in that... The method for synthesizing the compound shown in formula (II) is as follows: The compound shown in formula (III), the compound shown in formula (IV), potassium carbonate and tetratriphenylphosphine palladium were dissolved in a mixed solvent of tetrahydrofuran and water, and the mixture was heated under reflux. After the reaction was completed and cooled to room temperature, the mixture was extracted with dichloromethane, washed with saturated brine and dried. The solvent was removed by rotary evaporation. The concentrate was dissolved in eluent and purified by column chromatography. The eluent was collected and the eluent was removed by evaporation and dried to obtain a solid powder product, the compound shown in formula (II). The eluent used for column chromatography purification was petroleum ether and dichloromethane in a volume ratio of 2:

1. The structural formulas of the compounds shown in formula (III) and (IV) are as follows: 。 10. The application of the bibis(triphenylamine)benzothiadiazole compound according to claim 1 as a co-sensitizer in dye-sensitized solar cells.

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