A triad-containing conjugated bridge self-assembled monolayer material for perovskite solar cells and a preparation method thereof

Abstract

This invention belongs to the field of organic semiconductor functional materials and perovskite solar cell technology, and discloses a self-assembled monolayer material containing triple-bonded conjugated bridges for perovskite solar cells and its preparation method. This invention designs a self-assembled monolayer material with benzoic acid as the anchoring group, electron-rich triphenylamine derivatives or pyrene derivatives as head groups, and triple-bonded conjugated bridges as connecting units. The carbon-carbon triple bond (-C≡C-) conjugated bridge connecting units, with their unique rigid linear characteristics, can effectively suppress molecular relaxation vibrations, improve the self-assembly continuity and hole mobility of SAMs thin films, and simultaneously enhance the photothermal stability of the molecules, ultimately achieving a synergistic improvement in device efficiency and stability.

Description

Technical Field

[0001] This invention belongs to the field of organic semiconductor functional materials and perovskite solar cell technology, specifically relating to a self-assembled monolayer material with triple bonds as conjugated bridges, its preparation method, and its application in perovskite solar cells. Background Technology

[0002] Driven by the "dual carbon" goal, perovskite solar cells (PSCs) have become a research hotspot in the photovoltaic field due to their advantages such as simple fabrication process, tunable material bandgap, and high photoelectric conversion efficiency. Among them, inverted (pin) structure PSCs show significant industrial application prospects due to their ability to be fabricated using low-temperature processes and their good compatibility with flexible substrates and tandem cell technologies. In these devices, the hole transport layer plays a crucial role in the device's performance, and self-assembled monolayers (SAMs), with their molecular-level structural controllability, energy level tunability, and excellent solution processing compatibility, have become one of the key material systems for achieving efficient hole extraction and transport. Nat. Photon. 2024, 18, 1243-1253; Adv. Mater. 2025, 37, 2502032.).

[0003] SAMs materials typically consist of three parts: anchoring groups, linking units, and head groups. Current research mainly focuses on the structural design of the head groups, such as by chemically modifying derivatives like carbazole and triphenylamine to modulate the dipole moment and energy level structure of the molecule, thereby optimizing its hole transport performance. ACS Energy Lett. 2025, 10, 4882; Small 2025, 21, 2503114. However, current research on the connecting units of SAMs materials remains relatively scarce. Existing studies mostly employ traditional structures such as alkyl chains, benzene rings, or thiophenes. These connecting units have significant limitations in key aspects such as molecular order regulation, dipole interaction modulation, and charge transport efficiency. Flexible alkyl chains have poor conjugation, which is not conducive to charge delocalization, and are prone to degradation under high-energy ultraviolet light, resulting in insufficient interfacial stability. Meanwhile, benzene rings and thiophene bridging groups, due to the presence of single-bond rotational barriers, easily cause molecular vibrational energy loss and anisotropy in charge transport, thus limiting further improvements in device performance. Mater. Today 2025, 89, 192; Nano-Micro Lett. (2026, 18, 241.). Therefore, there is an urgent need to design and develop high-performance SAMs materials with novel interconnecting units to precisely match the actual application requirements of high-efficiency perovskite solar cells and provide core support for improving device performance. Summary of the Invention

[0004] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this invention is to develop a self-assembled monolayer material with triple bonds as conjugated bridges and its preparation method, and to apply it to perovskite solar cells, aiming to solve the bottlenecks of poor continuity, poor stability and insufficient charge transport efficiency of existing SAMs thin films.

[0005] To achieve the above objectives, this invention designs a self-assembled monolayer material with benzoic acid as the anchoring group, electron-rich triphenylamine derivatives or pyrene derivatives as head groups, and triple-bonded conjugated bridges as connecting units. The carbon-carbon triple bond (-C≡C-) conjugated bridge connecting units, possessing unique rigid linear characteristics, can effectively suppress molecular relaxation vibrations, improve the self-assembly continuity and hole mobility of SAMs films, and simultaneously enhance the photothermal stability of the molecules, ultimately achieving a synergistic improvement in device efficiency and stability.

[0006] The technical solution adopted in this invention is as follows: A self-assembled monolayer material containing triple-bonded conjugated bridges, using triple-bonded conjugated bridges as connecting units, benzoic acid as an anchoring group, and electron-rich triphenylamine derivatives or pyrene derivatives as head groups, has the following general chemical structural formula: ; Wherein, M is a triphenylamine derivative or a pyrene derivative, specifically one of the following structural formulas: ; Wherein, R is one of H, F, Cl, Br, I, ―Me, ―OMe or ―SMe.

[0007] The synthesis method of the self-assembled monolayer material containing triple-bonded conjugated bridges is as follows: Compound 1 undergoes a Sonogashira reaction with methyl 4-ethynylbenzoate to obtain intermediate compound 2; Compound 2 undergoes a hydrolysis reaction under the action of a strong base to obtain the final product, self-assembled monolayer material 3 containing triple-bonded conjugated bridges. The specific reaction steps are as follows: (i) Under nitrogen protection, compound 1 MBr or MI, methyl 4-ethynylbenzoate, cuprous iodide, palladium dichloride of bis(triphenylphosphine) chloride and triethylamine were dissolved in a dry toluene solution, and then the mixture was heated to 80-90 °C and reacted for 12-15 h. After the reaction was completed, the reaction solution was cooled to room temperature and extracted and separated several times with ethyl acetate solution. The organic layer was collected, the solvent was removed under reduced pressure, the collected product was separated and purified by silica gel chromatography, and dried under vacuum to obtain intermediate compound 2. (ii) Dissolve intermediate compound 2 and potassium hydroxide in a mixed solvent of tetrahydrofuran and water, then heat to 65-70℃ and reflux for 12-15 h. After the reaction is completed, cool the reaction solution to room temperature, remove the solvent by vacuum distillation and add deionized water, then add hydrochloric acid aqueous solution to neutralize the reaction solution to a pH value between 5 and 6. Subsequently, extract and separate the reaction solution several times with ethyl acetate solution, collect the organic layer, remove the solvent under reduced pressure, separate and purify the collected product by column chromatography, and dry under vacuum to obtain the final product 3.

[0008] The synthesis process is as follows: .

[0009] In step (i), the molar ratio of compound 1: methyl 4-ethynylbenzoate: cuprous iodide, bis(triphenylphosphine)palladium dichloride and triethylamine is 1:1.2~2:0.01:0.1:1; in the toluene solution, the concentration of compound 1 is 0.1~0.2 mol / L.

[0010] In step (ii), the molar ratio of intermediate compound 2 to potassium hydroxide is 1:25 ~ 35; in the mixed solvent of tetrahydrofuran and water, the concentration of intermediate compound 2 is 0.05 ~ 0.2 mol / L, and the concentration of hydrochloric acid aqueous solution is 2 mol / L.

[0011] In a mixed solvent of tetrahydrofuran and water, the volume ratio of tetrahydrofuran to water is 5:1.

[0012] The self-assembled monolayer material containing triple-bonded conjugated bridges obtained in this invention is used as a hole transport layer in a perovskite solar cell. The perovskite solar cell comprises a transparent conductive substrate, a hole transport layer, a perovskite photoactive layer, an electron transport layer, a hole blocking layer, and a metal electrode. The specific steps for its fabrication are as follows: (1) Cut the transparent conductive substrate into a fixed size and perform etching. Clean the etched conductive substrate in different solvents by ultrasonication, and then treat it with ultraviolet ozone. (2) The conductive substrate prepared in step (1) is transferred to a glove box. An ethanol solution containing a self-assembled monolayer material with triple bond conjugated bridge is applied to the conductive substrate by spin coating or immersion. The self-assembled monolayer hole transport layer is prepared by sintering at 100-120℃ for 5-10 minutes. (3) The perovskite precursor solution is spin-coated onto the self-assembled monomolecular hole transport layer by spin coating, and an antisolvent is added during the spin coating process to form a perovskite photoactive layer. (4) An organic electron transport layer and a hole blocking layer are prepared sequentially on the perovskite photoactive layer by spin coating or vacuum evaporation. (5) The metal electrode is deposited onto the hole blocking layer by vacuum evaporation.

[0013] In step (1), the transparent conductive substrate is one of FTO conductive glass, ITO conductive glass, or transparent flexible conductive substrate; the solvent is, in order, deionized water, acetone, and ethanol. In step (2), the ethanol solution containing the self-assembled monolayer material with triple-bonded conjugated bridges is prepared by dissolving 0.2-2 mg of the self-assembled monolayer material containing triple-bonded conjugated bridges in 1 mL of ethanol; In step (3), the perovskite precursor solution is prepared by: in a glove box, mixing and dissolving cesium iodide, cesium bromide, formamidine iodide, methylamine iodide, lead iodide, lead bromide, and methylamine chloride in a specific ratio of 4:1. N, N - Dimethylformamide: Dimethyl sulfoxide is added to a mixed solution and then stirred at room temperature to obtain a perovskite precursor solution; the antisolvent is one of chlorobenzene, diethyl ether, ethyl acetate or anisole; In step (4), the organic electron transport layer is C 60 or PC 61 One type of BM has a hole blocking layer called BCP; In step (5), the metal electrode is one of gold, silver or copper.

[0014] (2), (3), (4), and (5) are all performed in a glove box filled with nitrogen.

[0015] This invention has the following advantages: The self-assembled monolayer material containing triple-bonded conjugated bridging groups provided by this invention uses benzoic acid as the anchoring group, triphenylamine derivatives or pyrene derivatives as the head groups, and triple-bonded conjugated bridges as the connecting units. This type of material simultaneously possesses uniquely rigid and linear carbon-carbon triple bonds with weak electron-withdrawing properties and strong conjugation, which is beneficial for precisely controlling the molecular dipole moment and interfacial electrostatic potential, achieving fine modulation of the ITO work function, and forming efficient charge delocalization channels, significantly improving hole mobility. Furthermore, this type of material exhibits good ultraviolet light tolerance, effectively enhancing the photothermal stability of the material. The self-assembled monolayer material containing triple-bonded conjugated bridging groups provided by this invention achieved a photoelectric conversion efficiency of >23.5% in perovskite solar cells and exhibited good photothermal stability, which will help promote the commercial development of perovskite solar cells. Attached Figure Description

[0016] Figure 1 The molecular structure of a self-assembled monomolecule material containing a triple-bonded conjugated bridging group prepared according to the present invention; Figure 2A schematic diagram of the inverted perovskite solar cell structure prepared according to the present invention; Figure 3 This is a perovskite solar cell based on an ABT self-assembled monomolecular hole transport layer, as described in Example 1 of the present invention. JV Curve graph (light intensity 100 mW / cm) 2 ); Figure 4 This is a perovskite solar cell based on a TTPC self-assembled monomolecular hole transport layer, as described in Example 2 of the present invention. JV Curve graph (light intensity 100 mW / cm) 2 ); Figure 5 This is a perovskite solar cell based on a PyTPC self-assembled monomolecular hole transport layer, as described in Example 3 of the present invention. JV Curve graph (light intensity 100 mW / cm) 2 ); Figure 6 This invention provides a comparative example 1 of a perovskite solar cell based on a commercially available 4PACz self-assembled monomolecular hole transport layer. JV Curve graph (light intensity 100 mW / cm) 2 ). Detailed Implementation

[0017] The present invention will be further described below with reference to specific implementation examples to enable those skilled in the art to better understand the present invention. However, the scope of protection of the present invention is not limited to the following embodiments, and the scope of the present invention should be determined by the claims.

[0018] Example 1

[0019] Synthesis of ABT, a self-assembled monolayer material containing triple-bonded conjugated bridging groups, and its application in perovskite solar cells: ; (i) Under nitrogen protection, compound 1 (2.50 g, 4.84 mmol), methyl 4-ethynylbenzoate (1.16 g, 7.25 mmol), cuprous iodide (0.01 g, 0.052 mmol), palladium dichloride bis(triphenylphosphine) (0.34 g, 0.48 mmol), and triethylamine (0.49 g, 4.84 mmol) were dissolved in a dry toluene solution (40 mL), and the mixture was heated to 80 °C and reacted for 12 h. After the reaction was complete, the reaction solution was cooled to room temperature and extracted three times with ethyl acetate solution (150 mL). The organic layer was collected, the solvent was removed under reduced pressure, and the collected product was separated by silica gel chromatography using petroleum ether / ethyl acetate (5:1 vol / vol) as eluent. The product was dried under vacuum to give a red solid intermediate compound 2 (2.47 g, 85.6%). 1 H NMR (400 MHz, DMSO-) d 6 ) δ = 8.05 – 8.00 (m, 3H), 7.94 – 7.87 (m, 2H), 7.84 – 7.74(m, 3H), 7.18 – 7.05 (m, 4H), 7.02 – 6.91 (m, 4H), 6.90 – 6.79 (m, 2H), 3.87(s, 3H), 3.75(s, 6H). (ii) Intermediate compound 2 (0.50 g, 0.84 mmol) and potassium hydroxide (1.41 g, 25.2 mmol) were dissolved in tetrahydrofuran (10 mL) and water (2 mL), and then the mixture was refluxed at 70 °C for 12 h. After the reaction was completed, the reaction solution was cooled to room temperature, the solvent was removed by vacuum distillation, and deionized water was added. Then, 2 M hydrochloric acid aqueous solution was added to neutralize the reaction solution to pH≈6. Subsequently, the reaction solution was extracted three times with ethyl acetate solution (150 mL), the organic layer was collected, the solvent was removed under reduced pressure, and the collected material was purified by column chromatography using dichloromethane / methanol (10:1 vol / vol) as eluent and dried under vacuum to obtain the red self-assembled monolayer material ABT (0.44 g, 89.2%). 1 H NMR (400 MHz, THF- d 8) δ = 7.98– 7.91 (m, 2H), 7.86 – 7.74 (m, 3H), 7.67 – 7.56 (m, 3H), 7.03 – 6.97 (m,4H), 6.90 – 6.84 (m, 2H), 6.80 – 6.73 (m, 4H), 3.65 (s, 6H). 13 C NMR (101 MHz, THF- d 8 ) δ = 166.0, 156.7, 155.5, 153.1, 149.5, 140.3, 134.7, 133.3, 131.4,130.8, 129.9, 129.6, 128.1, 127.3, 127.0, 125.7, 119.0, 114.6, 113.9, 94.2,88.3, ​​67.0, 66.9, 66.8, 66.7, 66.6, 66.4, 66.2, 66.0, 54.7, 24.9, 24.8, 24.7,24.6, 24.5, 24.4, 24.2, 24.0, 18.1. HRMS: Calculated value: C 35 H 25 N3O4S 584.1566, measured value: 584.1558. The self-assembled monolayer material ABT, synthesized above with triple bonds as conjugated bridges, is applied in perovskite solar cells. Its preparation method and process are as follows: The perovskite solar cell has the following structure: ITO / ABT / perovskite photoactive layer / C 60 The fabrication process of the perovskite solar cell, / BCP / Ag, is as follows: (1) Cut the ITO (indium tin oxide) conductive glass into glass substrates of 15 mm × 15 mm in size and etch them using an etching machine. Clean the etched glass substrates in deionized water, acetone and ethanol in sequence by ultrasonic cleaning for 30 min, and then place them in an ultraviolet ozone generator for 30 min.

[0020] (2) Preparation of organic self-assembled monomolecular hole transport layer by spin coating. First, 1.2 mg of ABT was dissolved in 1 mL of ethanol and then thoroughly shaken to mix evenly, obtaining a precursor solution for the self-assembled monomolecular hole transport layer. Finally, 30 μL of the solution was pipetted onto an ITO conductive substrate, with the spin coating speed controlled at 4000 rpm and the spin coating time at 20 s. The self-assembled monomolecular hole transport layer film was then annealed and calcined at 100 ℃ for 10 min to obtain a dense and uniform ABT self-assembled monomolecular hole transport layer film.

[0021] (3) The perovskite photoactive layer was prepared by spin coating. In a glove box, cesium iodide (8.0 mg, 0.031 mmol), cesium bromide (9.6 mg, 0.045 mmol), methylamine iodide (11.9 mg, 0.075 mmol), formamidinium iodide (232.2 mg, 1.350 mmol), lead iodide (691.5 mg, 1.50 mmol), lead bromide (16.5 mg, 0.045 mmol), and methylamine chloride (12.0 mg, 0.18 mmol) were dissolved in 1 mL of a 4:1 volume ratio solution. N , N A perovskite precursor solution was obtained by stirring a mixture of dimethylformamide and dimethyl sulfoxide at room temperature. 50 μL of the prepared perovskite precursor solution was spin-coated onto an ABT self-assembled monomolecular hole transport layer film using a spin coater at 4000 rpm for 35 s. Five seconds before the end of the spin-coating process, 200 μL of chlorobenzene was added to the film. The perovskite film was then annealed and calcined at 100 °C for 30 min to obtain a dense and uniform perovskite film.

[0022] (4) Electron transport layer and hole blocking layer were prepared by vacuum evaporation. High-purity C was selected. 60 BCP and BCP were successively and uniformly deposited onto the perovskite film at rates of approximately 0.2 and 0.5 Å / s, respectively, with deposition thicknesses of 25 and 8 nm, respectively.

[0023] (5) The counter electrode was prepared using vacuum evaporation. High-purity silver was uniformly deposited onto the device film at a rate of approximately 0.5 Å / s, with a deposition thickness of 100 nm. Furthermore, a specific mold was used to ensure that the gold deposition area was 20 mm². 2 .

[0024] Based on the perovskite solar cell prepared in Example 1, perovskite solar cell devices were fabricated and characterized according to the above procedure. The current-voltage (current-voltage) performance of the cell devices was analyzed. JV Characteristic curves are shown below. Figure 3 Open circuit voltageV oc The voltage is 1.184V, and the short-circuit current density is... J sc It is 25.87 mA·cm -2 Fill factor FF The photoelectric conversion efficiency is 26.19%, which is 85.49%.

[0025] Example 2

[0026] Synthesis of TTPC, a self-assembled monolayer material containing triple-bonded conjugated bridging groups, and its application in perovskite solar cells: ; (i) Under nitrogen protection, compound 3 (2.35 g, 6.33 mmol), methyl 4-ethynylbenzoate (1.52 g, 9.50 mmol), cuprous iodide (12 mg, 0.063 mmol), bis(triphenylphosphine)palladium dichloride (0.44 g, 0.63 mmol), and triethylamine (0.64 g, 6.33 mmol) were dissolved in a dry toluene solution (40 mL), and the mixture was heated to 85 °C and reacted for 14 h. After the reaction was complete, the reaction solution was cooled to room temperature and extracted three times with ethyl acetate solution (150 mL). The organic layer was collected, the solvent was removed under reduced pressure, and the collected product was separated by silica gel chromatography using petroleum ether / ethyl acetate (5:1 vol / vol) as eluent. The product was dried under vacuum to give a red solid intermediate compound 4 (2.08 g, 81.6%). 1 H NMR (600 MHz, DMSO-) d 6 ) δ = 7.99 – 7.91 (m, 2H), 7.66 – 7.59 (m, 2H), 7.46 – 7.40(m, 2H), 7.38 – 7.31 (m, 4H), 7.16 – 7.04 (m, 6H), 6.91 – 6.84 (m, 2H), 3.85(s, 3H). (ii) Intermediate compound 4 (0.50 g, 1.24 mmol) and potassium hydroxide (1.74 g, 30.98 mmol) were dissolved in tetrahydrofuran (10 mL) and water (2 mL), and then the mixture was refluxed at 70 °C for 13 h. After the reaction was completed, the reaction solution was cooled to room temperature, the solvent was removed by vacuum distillation, and deionized water was added. Then, 2 M hydrochloric acid aqueous solution was added to neutralize the reaction solution to pH ≈ 6. Subsequently, the reaction solution was extracted three times with ethyl acetate solution (150 mL), the organic layer was collected, the solvent was removed under reduced pressure, and the collected material was purified by column chromatography using dichloromethane / methanol (10:1 vol / vol) as eluent and dried under vacuum to obtain a pale yellow self-assembled monolayer material TTPC (0.40 g, 83.2%). 1 H NMR (600 MHz, DMSO- d 6 ) δ =7.95 (d, J = 8.0 Hz, 2H), 7.69 – 7.57 (m, 2H), 7.45 (d, J = 8.3 Hz, 2H), 7.37(t, J = 7.7 Hz, 4H), 7.13 (dd, J = 27.5, 7.7 Hz, 6H), 6.91 (d, J = 8.3 Hz, 2H). 13 C NMR (151 MHz, DMSO- d 6 δ = 167.2, 148.6, 146.8, 133.3, 131.7, 130.6, 130.3, 130.0, 130.0, 127.5, 125.7, 124.8, 124.2, 121.3, 114.3, 93.1, 88.3, ​​40.5, 40.4, 40.3, 40.1, 40.0, 39.9, 39.7, 39.6. HRMS: Calculated value: C 27 H 19 NO2390.1494, Measured value: 390.1492. The self-assembled monolayer material TTPC, synthesized above with triple bonds as conjugated bridges, is applied in perovskite solar cells. Its preparation method and process are as follows: The perovskite solar cell has the following structure: ITO / TTPC / perovskite photoactive layer / C 60The fabrication process of the 1.55 eV bandgap perovskite solar cell (BCP / Ag) is as follows: (1) Cut the ITO (indium tin oxide) conductive glass into glass substrates of 15 mm × 15 mm in size and etch them using an etching machine. Clean the etched glass substrates in deionized water, acetone and ethanol in sequence by ultrasonic cleaning for 30 min, and then place them in an ultraviolet ozone generator for 30 min.

[0027] (2) Preparation of organic self-assembled monomolecular hole transport layer by spin coating. First, 0.5 mg of TTPC was dissolved in 1 mL of ethanol, and then the mixture was thoroughly shaken to obtain a self-assembled monomolecular hole transport layer precursor solution. Finally, 30 μL of the solution was pipetted onto an ITO conductive substrate, with the spin coating speed controlled at 3000 rpm and the spin coating time at 30 s. The self-assembled monomolecular hole transport layer film was then annealed and calcined at 100 ℃ for 10 min to obtain a dense and uniform TTPC self-assembled monomolecular hole transport layer film.

[0028] (3) The perovskite photoactive layer was prepared by spin coating. In a glove box, cesium iodide (8.0 mg, 0.031 mmol), cesium bromide (9.6 mg, 0.045 mmol), methylamine iodide (11.9 mg, 0.075 mmol), formamidinium iodide (232.2 mg, 1.350 mmol), lead iodide (691.5 mg, 1.50 mmol), lead bromide (16.5 mg, 0.045 mmol), and methylamine chloride (12.0 mg, 0.18 mmol) were dissolved in 1 mL of a 4:1 volume ratio solution. N , N A perovskite precursor solution was prepared by stirring a mixture of dimethylformamide and dimethyl sulfoxide at room temperature. 50 μL of the prepared perovskite precursor solution with a band gap of 1.55 eV was spin-coated onto a TTPC self-assembled monomolecular hole transport layer film using a spin coater at 4000 rpm for 35 s. Five seconds before the end of the spin-coating process, 200 μL of chlorobenzene was added to the film. The perovskite film was then annealed and calcined at 100 °C for 30 min to obtain a dense and uniform perovskite film.

[0029] (4) Electron transport layer and hole blocking layer were prepared by vacuum evaporation. High-purity C was selected. 60 BCP and BCP were successively and uniformly deposited onto the perovskite film at rates of approximately 0.2 and 0.5 Å / s, respectively, with deposition thicknesses of 25 and 8 nm, respectively.

[0030] (5) The counter electrode was prepared using vacuum evaporation. High-purity silver was uniformly deposited onto the device film at a rate of approximately 0.5 Å / s, with a deposition thickness of 100 nm. Furthermore, a specific mold was used to ensure that the gold deposition area was 20 mm². 2 .

[0031] Based on the perovskite solar cell prepared in Example 2, perovskite solar cell devices were fabricated and characterized according to the above procedure. The current-voltage (current-voltage) performance of the cell devices was analyzed. JV Characteristic curves are shown below. Figure 4 Open circuit voltage V oc The voltage is 1.183V, and the short-circuit current density is... J sc It is 25.64 mA·cm -2 Fill factor FF The efficiency was 84.61%, and the photoelectric conversion efficiency was 25.66%.

[0032] Example 3

[0033] Synthesis of PyTPC, a self-assembled monolayer material containing triple-bonded conjugated bridging groups, and its application in perovskite solar cells: ; (i) Under nitrogen protection, compound 5 (2.10 g, 6.36 mmol), methyl 4-ethynylbenzoate (1.22 g, 7.63 mmol), cuprous iodide (12 mg, 0.064 mmol), palladium dichloride bis(triphenylphosphine) (0.45 g, 0.64 mmol), and triethylamine (0.64 g, 6.36 mmol) were dissolved in a dry toluene solution (40 mL), and the mixture was heated to 87 °C and reacted for 15 h. After the reaction was complete, the reaction solution was cooled to room temperature and extracted three times with ethyl acetate solution (150 mL). The organic layer was collected, the solvent was removed under reduced pressure, and the collected product was separated by silica gel chromatography using petroleum ether / ethyl acetate (6:1 vol / vol) as eluent. The product was dried under vacuum to give a red solid intermediate compound 6 (2.13 g, 92.5%). The intermediate compound 6 obtained in this step was directly proceeded to the next reaction without having its structure determined by nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry.

[0034] (ii) Intermediate compound 6 (0.50 g, 1.38 mmol) and potassium hydroxide (2.32 g, 41.39 mmol) were dissolved in tetrahydrofuran (10 mL) and water (2 mL), and then the mixture was refluxed at 70 °C for 12 h. After the reaction was completed, the reaction solution was cooled to room temperature, the solvent was removed by vacuum distillation, and deionized water was added. Then, 2 M hydrochloric acid aqueous solution was added to neutralize the reaction solution to pH ≈ 6. Subsequently, the reaction solution was extracted three times with ethyl acetate solution (150 mL), the organic layer was collected, the solvent was removed under reduced pressure, and the collected product was purified by column chromatography using dichloromethane / methanol (10:1 vol / vol) as eluent and dried under vacuum to obtain a white self-assembled monolayer material PyTPC (0.41 g, 86.1%). 1 H NMR (400 MHz, DMSO- d 6 ) δ= 7.82 – 7.69 (m, 6H), 7.43 (dd, J = 5.1, 2.0 Hz, 5H), 7.34 (s, 1H), 7.30 (s,1H). 13 C NMR (101 MHz, DMSO- d 6 δ = 189.1, 143.3, 135.3, 129.1, 40.7, 40.5, 40.2, 40.0, 39.8, 39.6, 39.4. HRMS: Calculated value: C 25 H 16 O2 371.1048, measured value: 371.1046. The self-assembled monolayer material PyTPC containing triple-bonded conjugated bridging groups synthesized above is applied in perovskite solar cells. Its preparation method and process are as follows: The perovskite solar cell has the following structure: ITO / PyTPC / perovskite photoactive layer / C 60 The fabrication process of the perovskite solar cell, / BCP / Ag, is as follows: (1) Cut the ITO (indium tin oxide) conductive glass into glass substrates of 15 mm × 15 mm in size and etch them using an etching machine. Clean the etched glass substrates in deionized water, acetone and ethanol in sequence by ultrasonic cleaning for 30 min, and then place them in an ultraviolet ozone generator for 30 min.

[0035] (2) Preparation of organic self-assembled monomolecular hole transport layer by spin coating. First, 0.5 mg of PyTPC was dissolved in 1 mL of ethanol, and then the mixture was thoroughly shaken to obtain a self-assembled monomolecular hole transport layer precursor solution. Finally, 30 μL of the solution was pipetted onto an ITO conductive substrate, with the spin coating speed controlled at 3000 rpm and the spin coating time at 30 s. The self-assembled monomolecular hole transport layer film was then annealed and calcined at 100 ℃ for 10 min to obtain a dense and uniform PyTPC self-assembled monomolecular hole transport layer film.

[0036] (3) The perovskite photoactive layer was prepared by spin coating. In a glove box, cesium iodide (8.0 mg, 0.031 mmol), cesium bromide (9.6 mg, 0.045 mmol), methylamine iodide (11.9 mg, 0.075 mmol), formamidinium iodide (232.2 mg, 1.350 mmol), lead iodide (691.5 mg, 1.50 mmol), lead bromide (16.5 mg, 0.045 mmol), and methylamine chloride (12.0 mg, 0.18 mmol) were dissolved in 1 mL of a 4:1 volume ratio solution. N , N A perovskite precursor solution was prepared by stirring a mixture of dimethylformamide and dimethyl sulfoxide at room temperature. 50 μL of the prepared perovskite precursor solution was then spin-coated onto a PyTPC self-assembled monomolecular hole transport layer film using a spin coater at 4000 rpm for 35 s. Five seconds before the end of the spin-coating process, 200 μL of chlorobenzene was added to the film. The perovskite film was then annealed and calcined at 100 °C for 30 min to obtain a dense and uniform perovskite film.

[0037] (4) Electron transport layer and hole blocking layer were prepared by vacuum evaporation. High-purity C was selected. 60 BCP and BCP were successively and uniformly deposited onto the perovskite film at rates of approximately 0.2 and 0.5 Å / s, respectively, with deposition thicknesses of 25 and 8 nm, respectively.

[0038] (5) The counter electrode was prepared using vacuum evaporation. High-purity silver was uniformly deposited onto the device film at a rate of approximately 0.5 Å / s, with a deposition thickness of 100 nm. Furthermore, a specific mold was used to ensure that the gold deposition area was 20 mm². 2 .

[0039] Based on the perovskite solar cell prepared in Example 3, perovskite solar cell devices were fabricated and characterized according to the above procedure. The current-voltage (current-voltage) performance of the cell devices was analyzed. JV Characteristic curves are shown below. Figure 5 Open circuit voltageV oc The voltage is 1.154V, and the short-circuit current density is... J sc 25.28 mA·cm -2 Fill factor FF The photoelectric conversion efficiency is 23.81%, which is 81.63%.

[0040] Comparative Example 1 The classic organic self-assembled monolayer hole transport material 4PACz was selected as the hole transport layer, and its structure is shown below: ; Comparative Example 1 was applied to perovskite solar cells, and its preparation method and process are as follows: The perovskite solar cell has the following structure: ITO / 4PACz / 1.55 ​​eV perovskite photoactive layer / C 60 The fabrication process of the 1.55 eV bandgap perovskite solar cell (BCP / Ag) is as follows: (1) Cut the ITO (indium tin oxide) conductive glass into glass substrates of 15 mm × 15 mm in size and etch them using an etching machine. Clean the etched glass substrates in deionized water, acetone and ethanol in sequence by ultrasonic cleaning for 30 min, and then place them in an ultraviolet ozone generator for 30 min.

[0041] (2) Preparation of organic self-assembled monomolecular hole transport layer by spin coating. First, 0.5 mg of 4PACz was dissolved in 1 mL of ethanol, and then the mixture was thoroughly shaken to obtain a self-assembled monomolecular hole transport layer precursor solution. Finally, 30 μL of the solution was pipetted onto an ITO conductive substrate, with the spin coating speed controlled at 3000 rpm and the spin coating time at 30 s. The self-assembled monomolecular hole transport layer film was then annealed and calcined at 100 ℃ for 10 min to obtain a dense and uniform 4PACz self-assembled monomolecular hole transport layer film.

[0042] (3) The perovskite photoactive layer was prepared by spin coating. In a glove box, cesium iodide (8.0 mg, 0.031 mmol), cesium bromide (9.6 mg, 0.045 mmol), methylamine iodide (11.9 mg, 0.075 mmol), formamidinium iodide (232.2 mg, 1.350 mmol), lead iodide (691.5 mg, 1.50 mmol), lead bromide (16.5 mg, 0.045 mmol), and methylamine chloride (12.0 mg, 0.18 mmol) were dissolved in 1 mL of a 4:1 volume ratio solution. N , NA perovskite precursor solution was prepared by stirring a mixture of dimethylformamide and dimethyl sulfoxide at room temperature. 50 μL of the prepared perovskite precursor solution was then spin-coated onto a 4PACz self-assembled monomolecular hole transport layer film using a spin coater at 4000 rpm for 35 s. Five seconds before the end of the spin-coating process, 200 μL of chlorobenzene was added to the film. The perovskite film was then annealed and calcined at 100 °C for 30 min to obtain a dense and uniform perovskite film.

[0043] (4) Electron transport layer and hole blocking layer were prepared by vacuum evaporation. High-purity C was selected. 60 BCP and BCP were successively and uniformly deposited onto the perovskite film at rates of approximately 0.2 and 0.5 Å / s, respectively, with deposition thicknesses of 25 and 8 nm, respectively.

[0044] (5) The counter electrode was prepared using vacuum evaporation. High-purity silver was uniformly deposited onto the device film at a rate of approximately 0.5 Å / s, with a deposition thickness of 100 nm. Furthermore, a specific mold was used to ensure that the gold deposition area was 20 mm². 2 .

[0045] Based on the perovskite solar cell fabricated in Comparative Example 1, perovskite solar cell devices were fabricated and characterized according to the above procedure. The current-voltage (current-voltage) performance of the cell devices was analyzed. JV Characteristic curves are shown below. Figure 6 Open circuit voltage V oc The voltage is 1.173V, and the short-circuit current density is... J sc It is 25.73 mA·cm -2 Fill factor FF The photoelectric conversion efficiency is 24.88%, which is 82.42%.

[0046] Figure 1 This invention relates to the molecular structure of a self-assembled monomolecule material with triple bonds as conjugated bridges, prepared according to the present invention.

[0047] Figure 2 This is a schematic diagram of the inverted perovskite solar cell structure prepared according to the present invention (wherein the hole transport layer is a single-molecule self-assembled hole transport layer).

[0048] Figure 3 This is a perovskite solar cell based on an ABT self-assembled monomolecular hole transport layer, as described in Example 1 of the present invention. JV Curve graph (light intensity 100 mW / cm) 2 As shown in the figure, the perovskite solar cell based on the ABT self-assembled monomolecular hole transport layer of Example 1 achieved a photoelectric conversion efficiency of 26.19%.

[0049] Figure 4 This is a perovskite solar cell based on a TTPC self-assembled monomolecular hole transport layer, as described in Example 2 of the present invention. JV Curve graph (light intensity 100 mW / cm) 2 As shown in the figure, the perovskite solar cell based on the TTPC self-assembled monomolecular hole transport layer of Example 2 achieved a photoelectric conversion efficiency of 25.66%.

[0050] Figure 5 This is a perovskite solar cell based on a PyTPC self-assembled monomolecular hole transport layer, as described in Example 3 of the present invention. JV Curve graph (light intensity 100 mW / cm) 2 As shown in the figure, the perovskite solar cell based on the PyTPC self-assembled monomolecular hole transport layer of Example 3 achieved a photoelectric conversion efficiency of 23.81%.

[0051] Figure 6 This invention provides a comparative example 1 of a perovskite solar cell based on a commercially available 4PACz self-assembled monomolecular hole transport layer. JV Curve graph (light intensity 100 mW / cm) 2 As shown in the figure, the perovskite solar cell based on the commercially available 4PACz self-assembled monomolecular hole transport layer of Comparative Example 1 achieved a photoelectric conversion efficiency of 24.88%.

Claims

1. A self-assembled monolayer material containing triple-bonded conjugated bridges, characterized in that, Using triple-bonded conjugated bridges as connecting units, benzoic acid as an anchoring group, and electron-rich triphenylamine derivatives or pyrene derivatives as head groups, the general chemical formula of the self-assembled monolayer material is as follows: ； Wherein, M is a triphenylamine derivative or a pyrene derivative, specifically one of the following structural formulas: ； Wherein, R is one of H, F, Cl, Br, I, ―Me, ―OMe or ―SMe.

2. The method for synthesizing a self-assembled monolayer material containing triple-bonded conjugated bridges as described in claim 1, characterized in that, Includes the following steps: (i) Under nitrogen protection, compound 1 MBr or MI, methyl 4-ethynylbenzoate, cuprous iodide, palladium dichloride of bis(triphenylphosphine) chloride and triethylamine were dissolved in a dry toluene solution, and then the mixture was heated to 80-90 °C and reacted for 12-15 h. After the reaction was completed, the reaction solution was cooled to room temperature and extracted and separated several times with ethyl acetate solution. The organic layer was collected, the solvent was removed under reduced pressure, the collected product was separated and purified by silica gel chromatography, and dried under vacuum to obtain intermediate compound 2. (ii) Dissolve intermediate compound 2 and potassium hydroxide in a mixed solvent of tetrahydrofuran and water, then heat to 65-70℃ and reflux for 12-15 h. After the reaction is completed, cool the reaction solution to room temperature, remove the solvent by vacuum distillation and add deionized water, then add hydrochloric acid aqueous solution to neutralize the reaction solution to a pH value between 5 and 6. Subsequently, extract and separate the reaction solution several times with ethyl acetate solution, collect the organic layer, remove the solvent under vacuum, separate and purify the collected product by column chromatography, and dry it under vacuum to obtain the final product 3. The synthesis process is as follows: .

3. The synthesis method as described in claim 2, characterized in that, In step (i), the molar ratio of compound 1: methyl 4-ethynylbenzoate: cuprous iodide, bis(triphenylphosphine)palladium dichloride and triethylamine is 1:1.2~2:0.01:0.1:1; in the toluene solution, the concentration of compound 1 is 0.1~0.2 mol / L.

4. The synthesis method according to claim 2, characterized in that, In step (ii), the molar ratio of intermediate compound 2 to potassium hydroxide is 1:25 ~ 35; in the mixed solvent of tetrahydrofuran and water, the concentration of intermediate compound 2 is 0.05 ~ 0.2 mol / L, and the concentration of hydrochloric acid aqueous solution is 2 mol / L; in the mixed solvent of tetrahydrofuran and water, the volume ratio of tetrahydrofuran to water is 5:

1.

5. The self-assembled monolayer material containing triple-bonded conjugated bridges as described in claim 1 is used as a hole transport layer in perovskite solar cells.

6. The use as described in claim 5, characterized in that, The perovskite solar cell described herein comprises a transparent conductive substrate, a hole transport layer, a perovskite photoactive layer, an electron transport layer, a hole blocking layer, and a metal electrode. The specific steps for its fabrication are as follows: (1) Cut the transparent conductive substrate into a fixed size and perform etching. Clean the etched conductive substrate in different solvents by ultrasonication, and then treat it with ultraviolet ozone. (2) The conductive substrate prepared in step (1) is transferred to a glove box. An ethanol solution of the self-assembled monolayer material containing triple bond conjugated bridges is applied to the conductive substrate by spin coating or immersion method. The self-assembled monolayer hole transport layer is prepared by sintering at 100-120℃ for 5-10 minutes. (3) The perovskite precursor solution is spin-coated onto the self-assembled monomolecular hole transport layer by spin coating, and an antisolvent is added during the spin coating process to form a perovskite photoactive layer. (4) An organic electron transport layer and a hole blocking layer are prepared sequentially on the perovskite photoactive layer by spin coating or vacuum evaporation. (5) The metal electrode is deposited onto the hole blocking layer by vacuum evaporation.

7. The use as described in claim 6, characterized in that, In step (1), the transparent conductive substrate is one of FTO conductive glass, ITO conductive glass or transparent flexible conductive substrate; the solvent is deionized water, acetone and ethanol in sequence.

8. The use as described in claim 6, characterized in that, In step (2), the ethanol solution containing the self-assembled monolayer material with triple-bonded conjugated bridges is prepared by dissolving 0.2-2 mg of the self-assembled monolayer material containing triple-bonded conjugated bridges in 1 mL of ethanol.

9. The use as described in claim 6, characterized in that, In step (3), the perovskite precursor solution is prepared by: in a glove box, mixing and dissolving cesium iodide, cesium bromide, formamidine iodide, methylamine iodide, lead iodide, lead bromide, and methylamine chloride in a specific ratio of 4:

1. N, N - Dimethylformamide: A mixed solution of dimethyl sulfoxide is stirred at room temperature to obtain a perovskite precursor solution; the antisolvent is one of chlorobenzene, diethyl ether, ethyl acetate or anisole.

10. The use as described in claim 6, characterized in that, In step (4), the organic electron transport layer is C 60 or PC 61 One type of BM has a hole blocking layer called BCP; In step (5), the metal electrode is one of gold, silver or copper; (2), (3), (4), and (5) are all performed in a glove box filled with nitrogen.

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