Benzamide derivative as well as preparation method and application thereof
By using benzamide derivatives as additives in perovskite solar cells, and taking advantage of the characteristics of two meta-CF3 structures and indole rings, the problems of crystal quality and energy level mismatch in perovskite films were solved, achieving efficient charge separation and improved stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHONGMAO LVNENG TECH (XIAN) CO LTD
- Filing Date
- 2026-02-11
- Publication Date
- 2026-05-08
AI Technical Summary
In existing perovskite solar cells, the crystal quality of the perovskite thin film, the density of surface and interface defects, and the energy level mismatch between the perovskite and the charge transport layer limit the device performance and stability. Existing additives cannot simultaneously achieve the functions of regulating crystallization, passivating defects, and optimizing energy levels.
By using benzamide derivatives as additives, the synergistic effect of strong electronic coordination and uniform spatial confinement is achieved through two meta-CF3 structures. Combined with the Lewis acid-base reaction and π-π stacking of the indole ring, defects are precisely passivated and the energy level arrangement is optimized, forming a perovskite crystal structure with low defect density and high crystallinity.
This method achieves uniform nucleation, ordered growth, and low-defect lattice of perovskite crystals, improving the charge separation efficiency and stability of perovskite solar cells, reducing interface charge accumulation, and promoting efficient hole transfer to the hole transport layer.
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Figure CN121990939A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery manufacturing technology, specifically relating to a benzamide derivative, its preparation method, and its application. Background Technology
[0002] Perovskite solar cells (PSCs) have become a research hotspot in the photovoltaic field due to their advantages such as high power conversion efficiency, low fabrication cost, and solution processability. Among them, inverted perovskite devices (pin structures) are more suitable for fabricating tandem devices with silicon-based solar cells due to their simple structure, low fabrication temperature, and good stability, and have broad prospects for commercial application.
[0003] However, the performance and stability of inverse perovskite devices are still limited by the crystal quality of the perovskite film, the density of surface and interface defects, and the energy level mismatch between the perovskite and the charge transport layer. Defects such as lead vacancies and iodine vacancies in the perovskite film lead to increased nonradiative recombination, reducing the open-circuit voltage and fill factor of the device; simultaneously, defects in the perovskite and hole transport layer, such as NiO, can cause further degradation. x Energy level mismatches between Me-4PACz or electron transport layers such as C60 and BCP can hinder charge extraction and affect device efficiency. Furthermore, the crystallization process of perovskite films easily forms defects such as pinholes and grain boundaries, further exacerbating device performance degradation.
[0004] To address these issues, the common approach is to add small organic molecule additives to regulate perovskite crystallization, passivate defects, and optimize energy level arrangement. For example, aniline derivatives such as phenylethylamine (PEA) and 4-fluorophenylethylamine (F-PEA) are used as additives, interacting with Pb on the perovskite surface through the amino groups in their molecules. 2+ It forms coordination bonds, passivates defects, and improves interfacial contact; compounds containing trifluoromethyl groups, due to their strong electron-withdrawing properties, can regulate molecular dipole moments and optimize energy level arrangement. However, existing additives often cannot simultaneously achieve the three functions of "regulating crystallization, passivating defects, and optimizing energy levels". Summary of the Invention
[0005] To address the aforementioned problems, this invention provides a benzamide derivative, its preparation method, and its applications. The specific technical solution is as follows.
[0006] A benzamide derivative, the structure of which is shown in formula (1): Equation (1); Wherein, L represents a -(CH2)n alkyl chain, n is 0~2, and R represents any one of hydrogen atom, 3-methyl-1H-indol-5-yl)oxy, (3-ethyl-1H-indol-5-yl)oxy or (3-isopropyl-1H-indol-5-yl)oxy.
[0007] The two meta-CF3 structures in this invention achieve a synergistic effect of strong electronic coordination and uniform spatial confinement. Their strong coordination delays nucleation, providing a time window for the formation of uniform crystal nuclei. The symmetrical spatial configuration ensures uniform dispersion of additive molecules, achieving global growth control. The superimposed steric hindrance effect inhibits abnormal grain growth, ultimately resulting in a perovskite crystal structure with low defect density, high crystallinity, and regular orientation. Compared to a single -CF3 or two non-meta-arranged -CF3 structures, the synergistic effect of electronic and steric hindrance is insufficient, failing to simultaneously achieve the control objectives of "uniform nucleation-ordered growth-low defect lattice." The resulting perovskite structure does not achieve good results in terms of grain size uniformity, lattice integrity, and grain boundary quality. Furthermore, R in the structure is an indole ring, a nitrogen-containing aromatic heterocycle. The lone pair electrons of the nitrogen atom on the ring can react with the low-coordinated Pb in the perovskite lattice through Lewis acid-base reactions. 2+ Strong coordination is formed, and Pb in perovskite films is precisely passivated. 2+ Cation defects caused by insufficient coordination.
[0008] In another preferred embodiment, the benzamide derivative is any one of the following compounds A1~A3 and B1~B3; .
[0009] The second aspect of this invention provides a method for preparing the aforementioned benzamide derivatives, wherein the preparation processes of compounds A1 and A2 are as follows: Using bromobenzene or benzyl bromo as raw materials, carboxylic acid intermediates are obtained through carboxylation reactions mediated by organometallic reagents; Using N,N-dimethylformamide as a catalyst, a carboxylic acid intermediate reacts with thionyl chloride under reflux to generate an acyl chloride intermediate. The acyl chloride is then directly added dropwise to an ammonia solution, followed by ammonolysis, crystallization, and drying to obtain the intermediate. The preparation process of compound A3 is as follows: Using palladium acetate and tris(o-methylphenyl)phosphine as a catalytic system and N,N-diisopropylethylamine as a base, bis(trifluoromethyl)bromobenzene and acrylamide were mixed in a mass ratio of 11~11.1:4~4.1 to carry out a Heck coupling reaction. The reaction solution was extracted, dried, concentrated, and then recrystallized from methanol and water to obtain an enamide intermediate. Using Raney nickel as a hydrogenation catalyst and ethanol as a solvent, the enamide intermediate was subjected to a catalytic hydrogenation reduction reaction under a hydrogen atmosphere to reduce the double bond to obtain a saturated amide. The reaction solution was then removed from the catalyst, concentrated, and dried by methanol slurry to obtain the final product.
[0010] In another preferred embodiment, A1 uses n-butyllithium as an organometallic reagent to dehydrogenate bromobenzene feedstock and then reacts it with dry ice to undergo a carboxylation reaction; wherein the molar mass ratio of n-butyllithium to bromobenzene is 45.05~45.15:37.54~37.64. A2 uses magnesium shavings as an organometallic reagent. After preparing a Grignard reagent with benzyl bromo, it undergoes carboxylation with dry ice. The reaction solution is extracted, and the pH is adjusted with dilute hydrochloric acid to crystallize and obtain a carboxylic acid intermediate. The mass ratio of magnesium shavings to benzyl bromo is 1.04~1.14:12.00~12.10. The mass ratio of N,N-diisopropylethylamine, the catalytic system, and bis(trifluoromethyl)bromobenzene is 9.7~9.75:0.94~0.99:11~11.05; in the catalytic system, the mass ratio of palladium acetate to tris(o-methylphenyl)phosphine is 0.25~0.30:0.69~0.74.
[0011] In another preferred embodiment, the preparation process of compounds B1-B3 is as follows: Using intermediate B as a substrate, it was reacted with any one of 5-hydroxy-3-methylindole, 5-hydroxy-3-ethylindole, and 5-hydroxy-3-isopropylindole, respectively, with potassium carbonate as the base and dimethyl sulfoxide as the solvent. The reaction was carried out at 120℃~125℃ for 4h~4.5h. The reaction solution was then extracted with ethyl acetate and water and washed with water. The precipitated solid was directly filtered and dried to obtain the corresponding target compounds B1~B3. Compound B1 was synthesized using 5-hydroxy-3-methylindole, compound B2 using 5-hydroxy-3-ethylindole, and compound B3 using 5-hydroxy-3-isopropylindole. In the preparation of compound B1, the mass ratio of intermediate B to reactants is 3.00~3.05:1.69~1.74; In the preparation of compound B2, the mass ratio of intermediate B to reactant is 4.00 g ~ 4.05 g : 2.46 g ~ 2.51 g; In the preparation of compound B3, the mass ratio of intermediate B to reactants is 3.00 g ~ 3.05 g : 2.10 g ~ 2.15 g; The structural formula of compound B is as follows: .
[0012] The specific synthesis process of compound B is as follows: Synthesis of intermediate B1-1: 20 g and 86.17 mmol of 2-fluoro-1,3-bis(trifluoromethyl)benzene were added to a reaction flask. 26 mL of concentrated sulfuric acid and 3.5 mL of acetic acid were added under ice-water bath. Then, 14.78 g and 51.7 mmol of dibromohydantoin were slowly added in batches. The mixture was heated to 60 °C and reacted for 6 h. After the reaction was completed, the reaction solution was slowly poured into ice water to dilute the sulfuric acid. The mixture was cooled to room temperature (23 °C), and the product was extracted with a mixed solvent of n-hexane and ethyl acetate. The solvent was removed by concentration under reduced pressure. The crude product was separated by column chromatography to obtain 22.48 g of intermediate B1-1, with a yield of 83.90%.
[0013] Synthesis of intermediate B1-2: Intermediate B1-1 was dissolved in diethyl ether, and an oxygen-free reaction atmosphere was created by nitrogen purging. After cooling to -78°C, 2M n-butyllithium was added dropwise, and the reaction was maintained at this temperature for 1 hour. The temperature was then further lowered to -90°C, and dry ice powder was added to initiate a carboxylation reaction. Subsequently, the temperature was naturally raised to room temperature. The reaction solution was concentrated under reduced pressure to remove the solvent, extracted with ethyl acetate and brine, and washed with water. The organic phase was concentrated, and the pH was adjusted with dilute hydrochloric acid. The precipitated solid was filtered and dried to obtain carboxylic acid intermediate B1-2.
[0014] Synthesis of Intermediate B: Using dichloroethane as solvent and intermediate B1-2 as substrate, two drops of DMF were added as an acylation catalyst. The mixture was heated to 80°C and thionyl chloride was added dropwise. The mixture was then refluxed at 83.5°C for 1 hour to complete the acylation. After the reaction, the solvent was removed by vacuum concentration, yielding a dichloroethane solution containing the acyl chloride intermediate. This solution was then slowly added dropwise to a diluted ammonia solution at 20°C for ammonolysis. The precipitated solid was filtered and dried to obtain the core intermediate B.
[0015] Synthesis of compounds B1 to B3: Using intermediate B as a common substrate, compounds B1, B2, and C3 were reacted with 5-hydroxy-3-methylindole, 5-hydroxy-3-ethylindole, and 5-hydroxy-3-isopropylindole, respectively, with potassium carbonate as the base and DMSO as the solvent. The reactions were heated to 120°C for 4 hours. After the reaction, the reaction solution was extracted with ethyl acetate and water, washed, and the precipitated solid was directly filtered and dried to obtain the corresponding target compounds B1 to B3. Specifically, 5-hydroxy-3-methylindole was used to synthesize compound B1, 5-hydroxy-3-ethylindole was used to synthesize compound B2, and 5-hydroxy-3-isopropylindole was used to synthesize compound B3.
[0016] A third aspect of the present invention provides the application of the aforementioned benzamide derivatives in the preparation of perovskite battery additives, wherein the perovskite battery additives are added to the perovskite light-absorbing layer.
[0017] In another preferred embodiment, the amount of the benzamide derivative added accounts for 1% to 1.5% of the mass of the perovskite light-absorbing layer.
[0018] The fourth aspect of the present invention provides a perovskite solar cell, the perovskite solar cell comprising an anode, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer and a cathode; wherein the perovskite light-absorbing layer contains a benzamide derivative as described in claim 1.
[0019] The third aspect of this invention provides that the specific process for obtaining the perovskite light-absorbing layer is as follows: After adding the benzamide derivative to the perovskite precursor solution, a perovskite film is deposited on the hole transport layer in one step using chlorobenzene as the antisolvent, followed by annealing to obtain the perovskite light absorption layer. The molar amount of benzamide derivatives in the perovskite precursor solution is 0.1 mmol to 0.2 mmol.
[0020] Compared with the prior art, the present invention has the following beneficial effects: The benzamide derivatives in this invention have two -CF3 groups in their structure, which have strong electron-withdrawing ability, resulting in a larger dipole moment. When added as an additive to the perovskite precursor solution, they exhibit an even stronger electron-withdrawing effect, enhancing the interaction between the additive and Pb. 2+ The coordination ability of metal cations slows down the decomposition and nucleation rate of precursors, making the nucleation process more uniform and controllable. Furthermore, the steric hindrance of the two -CF3 atoms creates a spatial confinement effect during the perovskite grain growth stage, inhibiting excessive grain growth and forcing the crystals to grow along the low surface energy direction, ultimately forming uniformly sized and regularly morphologically regular nanocrystals or microcrystals. In addition, the indole ring on the benzamide derivative in this invention, as a nitrogen-containing aromatic heterocycle, allows the lone pair electrons of the nitrogen atom on the ring to react with the poorly coordinated Pb in the perovskite lattice via Lewis acid-base reactions. 2+ Strong coordination is formed, and Pb in perovskite films is precisely passivated. 2+Insufficient coordination leads to cation defects. Simultaneously, the conjugated π system of the indole ring can interact electronically with halide vacancies at perovskite grain boundaries, reducing defect regeneration caused by halide migration. This is consistent with the classic mechanism of indole derivatives as perovskite defect passivators. At the crystallization regulation level, these substituents can form flexible bridging structures with the benzene ring through oxygen-linked chains, adsorbing onto the perovskite crystal nucleus surface to form "space-guided templates." The conjugated planar structure of the indole ring can induce perovskite crystal growth along preferred orientations through π-π stacking. Furthermore, the indole ring possesses excellent electronic conjugation properties; its HOMO energy level can be precisely aligned with the perovskite valence band edge through electron donation from the methyl group at position 3, promoting efficient hole transfer from within the perovskite to the hole transport layer and reducing interfacial charge accumulation. Simultaneously, this substituent forms a "donor-acceptor" push-pull electronic structure with the bis(trifluoromethyl) group in the molecule, enhancing the molecular dipole moment and optimizing the charge separation efficiency at the perovskite interface. The benzamide derivatives in this invention can simultaneously achieve three major functions: regulating crystallization, passivating defects, and optimizing energy levels through two meta-positioned -CF3 groups and an indole ring positioned between the two -CF3 groups. Attached Figure Description
[0021] Figure 1 The current-voltage curves are for different perovskite solar cells.
[0022] Figure 2 This is the NMR spectrum of compound A1.
[0023] Figure 3 This is the NMR spectrum of compound A2.
[0024] Figure 4 This is the NMR spectrum of compound A3.
[0025] Figure 5 This is the NMR spectrum of compound B1.
[0026] Figure 6 This is the NMR spectrum of compound B2.
[0027] Figure 7 This is the NMR spectrum of compound B3. Detailed Implementation
[0028] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0029] Trifluoromethyl groups are strong electron-withdrawing groups with significant steric hindrance. Their number directly determines the electron distribution, dipole moment, and steric hindrance strength of the additive molecule, thus affecting the perovskite crystallization behavior. This invention employs two -CF3 groups, resulting in a significantly stronger electron-withdrawing ability than the single- -CF3 structure in existing technologies. The benzamide derivatives in this invention also have a larger dipole moment. In perovskite precursor solutions, this stronger electron-withdrawing effect enhances the interaction between the additive and Pb²⁺. + The coordination ability of metal cations slows down the decomposition and nucleation rate of precursors, making the nucleation process more uniform and controllable. In contrast, existing technologies using single-CF3 structures have weaker coordination ability, resulting in faster precursor nucleation rates and a tendency for localized burst nucleation, leading to uneven perovskite grain size distribution and increased grain boundary defect density. Simultaneously, the steric hindrance of two CF3 cations creates a "spatial confinement" effect during perovskite grain growth, inhibiting excessive grain growth and forcing crystals to grow along low surface energy directions, ultimately forming uniformly sized and regularly shaped nanocrystals or microcrystals. Insufficient steric hindrance from single-CF3 cations fails to effectively limit grain growth, easily leading to large grains accompanied by numerous grain boundaries and lattice distortions, disrupting the integrity of the perovskite lattice. Furthermore, the substitution position determines the spatial configuration symmetry and electron distribution uniformity of the additive molecule, a key factor affecting its compatibility with the perovskite lattice. The meta-double substitution of this invention is fundamentally different from the substitution modes (ortho / para / random substitution) of existing technologies. The meta-bis-CF3 arrangement on the benzene ring (or other aromatic rings) has good spatial symmetry, which can avoid steric repulsion between substituents, allowing the additive molecules to remain monodisperse in the precursor solution and be uniformly adsorbed on the surface of the perovskite crystal nuclei, thus achieving global control over crystal growth. If ortho-substitution is used, the steric repulsion between the two -CF3 groups will cause the molecules to twist or aggregate, resulting in excessively high / low local additive concentrations, causing local differences in the growth rate of perovskite grains, forming irregular grains or defect-rich regions. If para-substitution is used, although the molecular symmetry is high, the electron distribution is biased towards both ends, resulting in an unbalanced local interaction with the perovskite lattice, which can easily induce lattice orientation disorder. Furthermore, the electron-withdrawing effect of meta-bis-CF3 is uniformly distributed on the aromatic ring, which can make the charge distribution of the additive molecules and the perovskite lattice, such as formamidine lead iodine and methylamine lead iodine lattice, more compatible, guiding the perovskite to grow along the preferred orientation, such as the (100) crystal plane, and improving the crystallinity and lattice order of the crystal. If the substitution position of the prior art destroys the uniformity of electron distribution, it will lead to an imbalance in the interaction between the additive and the perovskite lattice, which will not be able to effectively guide the crystal orientation, and finally form a random polycrystalline thin film with increased lattice strain.
[0030] The two meta-CF3 structures in this invention achieve a synergistic effect of strong electronic coordination and uniform spatial confinement: strong coordination delays nucleation, providing a time window for the formation of uniform crystal nuclei; the symmetrical spatial configuration ensures uniform dispersion of additive molecules, achieving global growth control; and the superimposed steric hindrance effect inhibits abnormal grain growth, ultimately resulting in a perovskite crystal structure with low defect density, high crystallinity, and regular orientation. Existing technologies typically employ single-CF3 or non-meta-double-CF3 structures. Due to insufficient synergy between electronic and steric hindrance effects, they cannot simultaneously achieve the control goals of uniform nucleation, ordered growth, and low-defect lattice. The resulting perovskite structures are not ideal in terms of grain size uniformity, lattice integrity, and grain boundary quality. The increase in the number of trifluoromethyl groups (two) and meta-substitution are not simple structural modifications, but rather, through enhanced electronic effects and optimized spatial configuration, achieve precise control of perovskite crystallization kinetics, ultimately directly improving the microstructure of perovskite.
[0031] The indole ring in R is a nitrogen-containing aromatic heterocycle, and the lone pair electrons of the nitrogen atom on the ring can react with the poorly coordinated Pb in the perovskite lattice via Lewis acid-base reactions. 2+ This forms a strong coordination interaction, precisely passivating cation defects in perovskite films caused by insufficient Pb²⁺ coordination; simultaneously, the conjugated π system of the indole ring can interact with halide vacancies (V1) at the perovskite grain boundaries. x - This process fosters electronic interactions, reducing defect regeneration caused by halide ion migration, consistent with the classic mechanism of indole derivatives as perovskite defect passivators. At the crystallization control level, these substituents can form flexible bridging structures with the benzene ring through oxygen-linked chains, adsorbing onto the perovskite crystal nucleus surface to form "space-guided templates." The conjugated planar structure of the indole ring can induce perovskite crystal growth along a preferred orientation through π-π stacking. Finally, the indole ring also possesses excellent electronic conjugation properties; its HOMO energy level can be precisely aligned with the perovskite valence band edge through electron donation from the methyl group at the 3-position, promoting efficient hole transfer from the perovskite interior to the hole transport layer and reducing interfacial charge accumulation. Simultaneously, this substituent forms a "donor-acceptor" push-pull electronic structure with the bis(trifluoromethyl) group in the molecule, enhancing the molecular dipole moment and optimizing the charge separation efficiency at the perovskite interface. All three structures in R are 3-alkyl-substituted indole-1-amines, specifically 3-alkyl-1H-indol-1-amine or 3-alkyl-1-aminoindole, differing only in the size of the alkyl group at the 3-position of the indole ring (methyl, ethyl, or isopropyl). When incorporated as an additive into perovskite precursor solutions, the alkyl group size determines the molecule's "occupancy" at grain boundaries / surfaces and its interaction with [PbX6]. 4- The strength of the skeletal interactions can be summarized as follows: the larger the alkyl group, the greater the steric hindrance, and the stronger the interaction with Pb². + Coordinating activity or with I -The reduction in hydrogen bonds slightly decreases the passivation strength, but improves grain orientation, reduces film stress, and increases humidity stability.
[0032] The following is a detailed description of a benzamide derivative, its preparation method, and its applications.
[0033] Example 1: A benzamide derivative, namely compound A1, has the following specific synthetic route: .
[0034] The specific synthesis process is as follows: Step 1, Synthesis of intermediate A1-1: ; 11 g (37.54 mmol) of 1,3-bis(trifluoromethyl)-5-bromobenzene and 120 mL of diethyl ether were added to a reaction flask. The gas was purged with nitrogen, and the temperature was lowered to -78 °C. Under controlled temperature, 2 M (23 mL) of 45.05 mmol of n-butyllithium was added dropwise. After the addition was complete, the temperature was maintained for 1 h. Then, the temperature was lowered to -90 °C, and 6.61 g (150.17 mmol) of dry ice powder was added. The temperature was naturally raised to room temperature (23 °C) for the reaction. After the reaction was completed, the solvent was removed by vacuum concentration. The mixture was extracted with ethyl acetate and brine and washed with water. The organic phase was concentrated until the amount of solvent remaining was reduced. Dilute hydrochloric acid was added to adjust the pH to 3-4. The precipitated solid was filtered and dried to obtain 5.91 g of intermediate A1-1, with a yield of 61%.
[0035] Step 2, Synthesis of Compound A1: ; 5.5 g (21.31 mmol) of intermediate A1-1 and 60 mL of dichloroethane were added to a reaction flask. Two drops of DMF were added as a catalyst for the acylation reaction. The temperature was raised to 80 °C, and 3.04 g (25.57 mmol) of thionyl chloride was added dropwise. After the addition was complete, the mixture was heated to reflux for 1 h. After the reaction was completed, the solvent was removed by vacuum concentration to obtain a dichloroethane solution containing intermediate A1-2. The solution was then slowly added dropwise to a diluted ammonia solution at 20 °C, precipitating a solid. The solid was filtered and dried to give 4.03 g of compound A1, with a yield of 73.60%. Its NMR information is as follows: Figure 2 As shown.
[0036] Example 2: A method for synthesizing a benzamide derivative, namely, the synthesis of compound A2, the specific synthetic route is shown below: .
[0037] The specific synthesis process is as follows: Step 1, Synthesis of intermediate A2-1: ; 1.04 g (42.99 mmol) of magnesium shavings and 0.5 g of iodine granules were added to the reaction flask as initiators. Nitrogen was used to purge the gas. 12 g (39.08 mmol) of 3,5-bis(trifluoromethyl)benzyl bromide was dissolved in 60 mL of diethyl ether and added dropwise to the system to initiate the Grignard reagent. After the addition was complete, the mixture was kept at this temperature for 1 h. 60 mL of diethyl ether was then added, and the temperature was lowered to -80 °C. 6.88 g (156.33 mmol) of dry ice powder was added, and the mixture was allowed to naturally warm to room temperature (23 °C) to react. After the reaction was complete, the solvent was removed by concentration under reduced pressure. The mixture was extracted with ethyl acetate and brine and washed with water. The organic phase was concentrated until only a small amount of solvent remained. Dilute hydrochloric acid was added to adjust the pH, and the precipitated solid was filtered and dried to obtain 7.23 g of intermediate A2-1, with a yield of 68%.
[0038] Step 2, Synthesis of compound A2: ; 7 g of intermediate A2-1 (25.72 mmol) and 60 mL of dichloroethane were added to a reaction flask. Two drops of DMF were added as a catalyst for the acylation reaction. The temperature was raised to 80 °C, and 4.59 g of thionyl chloride (38.58 mmol) was added dropwise. After the addition was complete, the mixture was heated to reflux for 1 h. After the reaction was completed, the solvent was removed by vacuum concentration to obtain a dichloroethane solution containing intermediate A2-2. The solution was then slowly added dropwise to a diluted ammonia solution at 20 °C, precipitating a solid. The solid was filtered and dried to obtain 4.96 g of compound A2, with a yield of 71.1%. Its NMR information is shown below. Figure 3 As shown.
[0039] Example 3: A method for synthesizing a benzamide derivative, namely, the synthesis of compound A3, the specific synthetic route is shown below: .
[0040] The specific synthesis process is as follows: Step 1, Synthesis of intermediate A3-1: ; 11 g (37.54 mmol) of 1,3-bis(trifluoromethyl)-5-bromobenzene, 4 g (56.31 mmol) of acrylamide, 9.70 g (75.08 mmol) of N,N-diisopropylethylamine, 0.25 g (1.13 mmol) of palladium acetate, 0.69 g (2.25 mmol) of tris(o-methylphenyl)phosphine, and 100 mL of dimethylformamide were added to a reaction flask. The atmosphere was purged with nitrogen, and the mixture was heated to 130 °C for 18 h. After the reaction was completed, the mixture was extracted with ethyl acetate and water, dried over anhydrous sodium sulfate, concentrated under reduced pressure, recrystallized from methanol and water, filtered, and dried to give 9.31 g of intermediate A3-1, with a yield of 87.6%.
[0041] Step 2, Synthesis of Compound A3: .
[0042] The high-pressure hydrogenation reactor was inspected, and a pressure holding test was completed. 565 μmol of Raney nickel was added, and after bubbling with nitrogen in ethanol for 10 min to remove oxygen, 8 g of intermediate A3-1 (28.25 mmol) was dissolved in 120 mL of ethanol and added to the reactor. The reactor was purged with nitrogen three times, followed by hydrogen three times. The pressure was increased to 0.2 MPa, and the reactor was heated to 45 °C for 18 h. After the reaction was complete, the temperature was lowered, the pressure was slowly released, and the reactor was purged with nitrogen three times. The reaction solution was passed through a diatomaceous earth funnel to remove the catalyst, and the solvent was removed by vacuum concentration to obtain the crude product. The crude product was pulped with methanol, filtered, and dried to finally obtain 6.36 g of solid compound A3, with a yield of 79%. Its NMR information is as follows: Figure 4 As shown.
[0043] Example 4: A method for synthesizing a benzamide derivative, namely, the synthesis of compound B1, is shown below: .
[0044] The specific synthesis process is as follows: Step 1, Synthesis of intermediate B1-1: .
[0045] 20 g (86.17 mmol) of 2-fluoro-1,3-bis(trifluoromethyl)benzene was added to a reaction flask. 26 mL of concentrated sulfuric acid and 3.5 mL of acetic acid were added under ice-water bath conditions. Then, 14.78 g (51.7 mmol) of dibromohydantoin was slowly added in batches. The mixture was heated and reacted for 6 h. After the reaction was completed, the reaction solution was slowly poured into ice water to dilute the concentrated sulfuric acid. The mixture was continuously cooled and a mixed solvent of n-hexane and ethyl acetate was added to extract the product. The solvent was removed by concentration under reduced pressure. The crude product was separated by column chromatography to obtain 22.48 g of intermediate B1-1, with a yield of 83.90%.
[0046] Step 2, Synthesis of intermediate B1-2: .
[0047] 22 g of intermediate B1-1 (70.74 mmol) and 220 mL of diethyl ether were added to a reaction flask. The gas was purged with nitrogen, and the temperature was lowered to -78 °C. Under controlled temperature, 45.05 mmol of 2 M / 38.9 mL n-butyllithium was added dropwise. After the addition was complete, the temperature was maintained for 1 h. Then, the temperature was lowered to -90 °C, and 12.45 g of 0.28 mol of dry ice powder was added. The temperature was naturally raised to room temperature (23 °C) for the reaction. After the reaction was completed, the solvent was removed by vacuum concentration. The mixture was extracted with ethyl acetate and brine and washed with water. The organic phase was concentrated until at least a small amount of solvent remained. The pH was adjusted by adding dilute hydrochloric acid, and the precipitated solid was filtered and dried to obtain 14.84 g of intermediate B1-2, with a yield of 76%.
[0048] Step 3, Synthesis of Intermediate B: 14.8 g and 53.6 mmol of intermediate B1-2, 120 mL of dichloroethane, and two drops of DMF were added to a reaction flask as catalysts for the acylation reaction. The mixture was heated to 80 °C and 9.56 g and 80.4 mmol of thionyl chloride were added dropwise. After the addition was complete, the mixture was heated to 83.5 °C and refluxed for 1 h. After the reaction was completed, most of the solvent was removed by vacuum concentration to obtain a solution containing the intermediate dichloroethane. The solution was slowly added dropwise to a diluted ammonia solution at 20 °C, and a solid precipitated. The solid was filtered and dried to obtain 13.05 g of intermediate B, with a yield of 88.5%.
[0049] Step 4, Synthesis of Compound B1: .
[0050] 3 g of intermediate B (10.90 mmol), 1.69 g of 5-hydroxy-3-methylindole (11.45 mmol), 3 g of potassium carbonate (21.81 mmol), and 25 mL of dimethyl sulfoxide were added to a reaction flask. The mixture was heated to 120 °C and reacted for 4 h. After the reaction was completed, the reaction solution was extracted with ethyl acetate and water, washed with water, and the precipitated solid was directly filtered and dried to give 1.49 g of compound B1, with a yield of 34%. Its NMR information is as follows: Figure 5 As shown.
[0051] Example 5: A method for synthesizing a benzamide derivative, namely, the synthesis of compound B2, is shown below: .
[0052] The specific synthesis process is as follows: Step 1, Synthesis of intermediate B1-1: ; 20 g (86.17 mmol) of 2-fluoro-1,3-bis(trifluoromethyl)benzene was added to a reaction flask. 26 mL of 98% concentrated sulfuric acid and 3.5 mL of acetic acid were added under ice-water bath conditions. Then, 14.78 g (51.7 mmol) of dibromohydantoin was slowly added in portions. The mixture was heated and reacted for 6 hours. After the reaction was complete, the reaction solution was slowly poured into ice water to dilute the concentrated sulfuric acid. The mixture was continuously cooled and a mixed solvent of hexane and ethyl acetate was added to extract the product. The solvent was removed by concentration under reduced pressure. The crude product was separated by column chromatography to obtain 22.48 g of intermediate B1-1, with a yield of 83.90%.
[0053] Step 2, Synthesis of intermediate B1-2: .
[0054] 22 g of intermediate B1-1 (70.74 mmol) and 220 mL of diethyl ether were added to a reaction flask. The gas was purged with nitrogen, and the temperature was lowered to -78 °C. Under controlled temperature, 2 M of 38.9 mL of 45.05 mmol of n-butyllithium was added dropwise. After the addition was complete, the temperature was maintained for 1 h. Then, the temperature was lowered to -90 °C, and 12.45 g of 0.28 mol of dry ice powder was added. The temperature was naturally raised to room temperature (23 °C) for the reaction. After the reaction was completed, the solvent was removed by vacuum concentration. The mixture was extracted with ethyl acetate and brine and washed with water. The organic phase was concentrated to remove the remaining solvent. Dilute hydrochloric acid was added to adjust the pH, and the precipitated solid was filtered and dried to obtain 14.84 g of intermediate B1-2, with a yield of 76%.
[0055] Step 3, Synthesis of Intermediate B: .
[0056] 14.8 g and 53.6 mmol of intermediate B1-2, 120 ml of dichloroethane, and two drops of dimethylformamide were added to a reaction flask as catalysts for the acylation reaction. The mixture was heated to 80 °C and 9.56 g and 80.4 mmol of thionyl chloride were added dropwise. After the addition was complete, the mixture was heated to 83.5 °C and refluxed for 1 h. After the reaction was completed, most of the solvent was removed by vacuum concentration to obtain a solution containing the intermediate dichloroethane. The solution was slowly added dropwise to a diluted ammonia solution at 20 °C, and a solid precipitated. The solid was filtered and dried to obtain 13.05 g of intermediate B, with a yield of 88.5%.
[0057] Step 4, Synthesis of Compound B2: .
[0058] 4 g (14.54 mmol) of intermediate B, 2.46 g (15.27 mmol) of 5-hydroxy-3-ethylindole, 4.02 g (29.08 mmol) of potassium carbonate, and 36 ml of dimethyl sulfoxide solvent were added to a reaction flask. The mixture was heated to 120 °C and reacted for 4 h. After the reaction was completed, the reaction solution was extracted with ethyl acetate and water, washed with water, and the precipitated solid was directly filtered and dried to give 1.31 g of compound B2, with a yield of 21.6%. Its NMR information is as follows: Figure 6 As shown.
[0059] Example 6: A method for synthesizing a benzamide derivative, namely, the synthesis of compound B3, the specific synthetic route is shown below: .
[0060] The specific synthesis process is as follows: Step 1, Synthesis of intermediate B1-1: 20 g (86.17 mmol) of 2-fluoro-1,3-bis(trifluoromethyl)benzene was added to a reaction flask. 26 mL of concentrated sulfuric acid and 3.5 mL of acetic acid were added under ice-water bath conditions. Then, 14.78 g (51.7 mmol) of dibromohydantoin was slowly added in batches. The mixture was heated and reacted for 6 h. After the reaction was completed, the reaction solution was slowly poured into ice water to dilute the sulfuric acid. The product was extracted with a mixed solvent of hexane and ethyl acetate while the temperature was continuously decreasing. The solvent was removed by concentration under reduced pressure. The crude product was separated by column chromatography to obtain 22.48 g of intermediate B1-1, with a yield of 83.90%.
[0061] Step 2, Synthesis of intermediate B1-2: .
[0062] 22 g of intermediate B1-1 (70.74 mmol) and 220 ml of diethyl ether were added to a reaction flask. The gas was purged with nitrogen, and the temperature was lowered to -78 °C. Under controlled temperature, 2 M, 38.9 ml, and 45.05 mmol of n-butyllithium were added dropwise. After the addition was complete, the temperature was maintained for 1 h, and then the temperature was lowered to -90 °C. 12.45 g of dry 0.28 mol of ice powder was added, and the temperature was naturally raised to room temperature (23 °C) for the reaction. After the reaction was completed, the solvent was removed by vacuum concentration. The mixture was extracted with ethyl acetate and brine and washed with water. The organic phase was concentrated to remove the remaining solvent. Dilute hydrochloric acid was added to adjust the pH, and the precipitated solid was filtered and dried to obtain 14.84 g of intermediate B1-2, with a yield of 76%.
[0063] Step 3, Synthesis of Intermediate B: .
[0064] 14.8 g and 53.6 mmol of intermediate B1-2, 120 ml of dichloroethane, and two drops of DMF were added to a reaction flask as catalysts for the acylation reaction. The mixture was heated to 80 °C and 9.56 g and 80.4 mmol of thionyl chloride were added dropwise. After the addition was complete, the mixture was heated to 83.5 °C and refluxed for 1 h. After the reaction was completed, most of the solvent was removed by vacuum concentration to obtain a solution containing the intermediate dichloroethane. The solution was slowly added dropwise to a diluted ammonia solution at 20 °C, and a solid precipitated. The solid was filtered and dried to obtain 13.05 g of intermediate B, with a yield of 88.5%.
[0065] Step 4, Synthesis of Compound B3: 3 g (10.9 mmol) of intermediate B, 2.10 g (11.99 mmol) of 5-hydroxy-3-isopropylindole, 3 g (21.81 mmol) of potassium carbonate, and 24 ml of dimethyl sulfoxide solvent were added to a reaction flask. The mixture was heated to 120 °C and reacted for 4 h. After the reaction was completed, the reaction solution was extracted with ethyl acetate and water, washed with water, and the precipitated solid was directly filtered and dried to finally give 1.44 g of compound B3, with a yield of 30.7%. Its NMR information is as follows: Figure 7 As shown.
[0066] Application Example 1: This application provides a perovskite solar cell, wherein the perovskite additive material in the perovskite solar cell is compound Al. The device structure is: FTO / hole transport layer / perovskite layer (containing compound) / electron transport layer / Ag.
[0067] FTO pretreatment: First, the 2.2mm thick FTO substrate was ultrasonically treated with deionized water, ethanol, and acetone for 15 minutes each. The cleaned FTO substrate was then placed in a forced-air drying oven and dried at 100℃ for 15 minutes. The dried FTO substrate was then placed in an ultraviolet ozone generator for ozone treatment for 25 minutes and set aside for later use.
[0068] Preparation of the hole transport layer: [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (Meo-2PACz) was mixed with ultra-dry ethanol to obtain a 1 mmol / L hole transport material solution. The obtained hole transport layer solution was spin-coated onto a prepared FTO surface and annealed at 100 °C for 10 min to obtain a hole transport layer with a thickness of 30 nm.
[0069] Preparation of the light-absorbing layer: PbI2, MABr, PbBr2, FAI, and CsI were dissolved in a mixed solution of DMF:DMSO = 4:1 to form a layer with the chemical formula CsI. 0.05 (MA 0.05 FA 0.95 ) 0.95 Pb(Br0.05 I 0.95 A perovskite precursor solution containing 3 was prepared, and compound A1 was added at a concentration of 0.1 mmol. Chlorobenzene was used as the antisolvent to deposit a perovskite film on the hole transport layer in one step. The film was then annealed at 105 °C for 10 min to obtain a perovskite layer with a thickness of 650 nm.
[0070] Preparation of electron transport layer: A layer of C60 and BCP were sequentially deposited on the perovskite layer to obtain an electron transport layer with a thickness of 35 nm.
[0071] Preparation of the cathode layer: A layer of Ag with a thickness of 100 nm is deposited on the electron transport layer.
[0072] Examples A2, A3, B1, B2, B3: The perovskite additive material in Application Example 1 was replaced with compound A2-B3, while the other materials, structures and preparation methods were the same as in Application Example 1.
[0073] Comparative Example 1 A method for preparing a perovskite solar cell differs from Example 1 in that: no benzamide derivatives are added when preparing the perovskite layer; all other materials, structures, and preparation methods are the same as in Example 1.
[0074] The performance of the perovskite solar cells in the above application examples and comparative application examples was tested, and the test results are shown in Table 1.
[0075] Table 1 Performance data of perovskite solar cells fabricated using comparative examples and application examples. As can be seen from the performance data in Table 1, the perovskite additive material obtained through specific molecular structure design can significantly improve the photoelectric conversion efficiency of inverted perovskite solar cells.
[0076] On the one hand, the amide group can anchor iodine vacancies through hydrogen bonding, achieving defect passivation and reducing nonradiative charge recombination. On the other hand, the π-conjugated system of the indole ring and the strong dipole interaction of the trifluoromethyl group jointly construct an interfacial dipole layer, improving charge separation efficiency, promoting efficient electron extraction and suppressing hole injection, thus increasing the fill factor. In addition, the strong hydrophobicity of the trifluoromethyl group can construct a dense protective layer, inhibiting water intrusion and ion migration. These multiple synergistic effects ultimately lead to a significant improvement in the photoelectric conversion efficiency of the battery.
[0077] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Many other changes and modifications can be made without departing from the concept and scope of the present invention. It should be understood that the present invention is not limited to the specific embodiments, and the scope of the present invention is defined by the appended claims.
Claims
1. A benzamide derivative, characterized in that, The structure of the benzamide derivative is shown in formula (1): Equation (1); Wherein, L represents a -(CH2)n alkyl chain, n is 0~2, and R represents any one of hydrogen atom, 3-methyl-1H-indol-5-yl)oxy, (3-ethyl-1H-indol-5-yl)oxy or (3-isopropyl-1H-indol-5-yl)oxy.
2. The benzamide derivative according to claim 1, characterized in that, The benzamide derivative is any one of the following compounds A1~A3 and B1~B3; 。 3. A method for preparing the benzamide derivative according to claim 2, characterized in that, The preparation processes of compounds A1 and A2 are as follows: Using bromobenzene or benzyl bromo as raw materials, carboxylic acid intermediates are obtained through carboxylation reactions mediated by organometallic reagents; Using N,N-dimethylformamide as a catalyst, a carboxylic acid intermediate reacts with thionyl chloride under reflux conditions to generate an acyl chloride intermediate, which is then crystallized by ammonolysis and dried to obtain the product. The preparation process of compound A3 is as follows: Using palladium acetate and tris(o-methylphenyl)phosphine as a catalytic system and N,N-diisopropylethylamine as a base, bis(trifluoromethyl)bromobenzene and acrylamide were mixed in a mass ratio of 11~11.1:4~4.1 to carry out a Heck coupling reaction. The reaction solution was extracted, dried, concentrated, and then recrystallized from methanol-water to obtain an enamide intermediate. Using Raney nickel as a hydrogenation catalyst and ethanol as a solvent, the enamide intermediate was subjected to a catalytic hydrogenation reduction reaction under a protective atmosphere to reduce the double bond to obtain a saturated amide. The reaction solution was then removed from the catalyst, concentrated, and dried to obtain the final product.
4. The method for preparing benzamide derivatives according to claim 3, characterized in that, A1 uses n-butyllithium as an organometallic reagent to dehydrogenate bromobenzene feedstock and then react it with dry ice to form a carboxylation reaction; wherein the molar mass ratio of n-butyllithium to bromobenzene is 45.05~45.15:37.54~37.
64. A2 uses magnesium shavings as an organometallic reagent. After preparing a Grignard reagent with benzyl bromide, it undergoes a carboxylation reaction with dry ice. The reaction solution is extracted, and the pH is adjusted with dilute hydrochloric acid to crystallize and obtain a carboxylic acid intermediate. The mass ratio of magnesium shavings to benzyl bromide is 1.04~1.14:12.00~12.
10. The mass ratio of N,N-diisopropylethylamine, the catalytic system, and bis(trifluoromethyl)bromobenzene is 9.7~9.75:0.94~0.99:11~11.05; in the catalytic system, the mass ratio of palladium acetate to tris(o-methylphenyl)phosphine is 0.25~0.30:0.69~0.
74.
5. A method for preparing the benzamide derivative according to claim 2, characterized in that, The preparation process of compounds B1~B3 is as follows: Using intermediate B as a substrate, it was reacted with any one of 5-hydroxy-3-methylindole, 5-hydroxy-3-ethylindole, and 5-hydroxy-3-isopropylindole as reactants, with potassium carbonate as the base and dimethyl sulfoxide as the solvent. The reaction was carried out at 120℃~125℃ for 4h~4.5h, and the mixture was extracted. The precipitated solid was directly filtered and dried to obtain the corresponding target compounds B1~B3. In the preparation of compound B1, the mass ratio of intermediate B to reactants is 3.00~3.05:1.69~1.74; In the preparation of compound B2, the mass ratio of intermediate B to reactant is 4.00 g ~ 4.05 g : 2.46 g ~ 2.51 g; In the preparation of compound B3, the mass ratio of intermediate B to reactants is 3.00 g ~ 3.05 g : 2.10 g ~ 2.15 g; The structural formula of compound B is as follows: 。 6. The use of the benzamide derivative of claim 2 in the preparation of a perovskite battery additive, wherein the perovskite battery additive is added to the perovskite light-absorbing layer.
7. The application according to claim 6, characterized in that, The amount of the benzamide derivative added accounts for 1% to 1.5% of the mass of the perovskite light-absorbing layer.
8. A perovskite solar cell, characterized in that, The perovskite solar cell includes an anode, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a cathode; the perovskite light-absorbing layer contains a benzamide derivative as described in claim 1.
9. The perovskite solar cell according to claim 8, characterized in that, The specific process for obtaining the perovskite light-absorbing layer is as follows: After adding the benzamide derivative to the perovskite precursor solution, a perovskite film is deposited on the hole transport layer in one step using chlorobenzene as the antisolvent, followed by annealing to obtain the perovskite light absorption layer. The molar amount of benzamide derivatives in the perovskite precursor solution is 0.1 mmol to 0.2 mmol.