Compounds based on imino structures, methods for their preparation and use

Abstract

The application belongs to the technical field of organic-inorganic lead halide perovskite solar cell preparation, and particularly relates to a compound based on imino structure and a preparation method and application thereof. The imino stilbene, imino dibenzyl and derivatives thereof with rigid conjugated plane are used as the matrix to ensure the hole transport capacity of the molecules. The molecular interface performance is controlled through conjugate extension means to reduce the energy loss at the interface. The alkyl phosphoric acid is used as the anchoring group to realize the self-assembly of the hole transport material on the electrode substrate. The preparation method is simple, the synthesis cost is low, and the prepared hole transport material can realize the dual functions of hole transport and perovskite interface passivation. When the material is applied to the inverted perovskite solar cell as the hole transport layer, the photoelectric conversion efficiency of >22% can be obtained without doping in the forward and reverse scans, the short-circuit current of the perovskite solar cell can be obviously improved, and the material has a wide application prospect.

Description

Technical Field

[0001] This invention specifically relates to compounds based on imino structures, their preparation methods, and applications, belonging to the field of organic-inorganic lead halide perovskite solar cell fabrication technology. Background Technology

[0002] Among the many renewable energy sources, solar energy has attracted much attention due to its advantages such as wide distribution and lack of geographical limitations, which has led to the rise of photovoltaic technology.

[0003] Perovskite solar cells (PVSCs) generally consist of five parts: transparent conductive glass (ITO / FTO), an electron transport layer, a perovskite layer, a hole transport layer, and metal electrodes. The perovskite layer is the core, responsible for absorbing sunlight and generating electron-hole pairs. The other layers work together to transport and collect charge. Based on the deposition order of the components, PVSCs can be divided into two types: nip structure and pin structure. Their working principle is that the perovskite layer absorbs photon energy, causing valence band electrons to jump and generate electron-hole pairs. Electrons are injected into the electron transport layer, and holes are injected into the hole transport layer. After being collected by the positive and negative electrodes, the electrons and holes move under the influence of the internal electric fields generated by the electrodes with different work functions, thus generating current. Different structures give these two types of cells different characteristics. Generally speaking, nip structure devices have higher photoelectric conversion efficiency, but their stability is somewhat lacking. Pin-structured devices exhibit less hysteresis due to the shorter distance holes travel to the hole transport layer / perovskite interface, while the mild fabrication process also facilitates printing or multilayer devices.

[0004] As a crucial component of PVSCs devices, the hole transport layer plays a vital role in extracting and transporting photogenerated holes, significantly contributing to improved device efficiency and stability. Currently, the commonly used hole transport material is poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), but its high price (>2000 RMB / gram) limits its large-scale application. Furthermore, PTAA exhibits poor wettability, resulting in weak adhesion between it and other layers.

[0005] To advance the development of inverted perovskite, the development of novel, inexpensive hole transport materials is imperative. These materials include inorganic compounds, metal complexes, conjugated polymers, and small organic molecules. Among these, small organic molecules, due to their advantages such as solution processability, rich and tunable structures, minimal batch-to-batch variability in synthesis, and ease of purification, are well-suited for comparative studies of the relationship between material structure and photovoltaic performance, and are widely used in PVSCs.

[0006] In summary, existing technologies have obvious shortcomings. Developing a high-performance, low-cost organic small molecule hole transport material is of great significance for the development of inverted perovskite solar cells. Summary of the Invention

[0007] This invention addresses the shortcomings of existing technologies by providing a compound based on an imino structure, its preparation method, and its applications. The preparation method is simple and has low synthesis costs. When the prepared hole transport material is used as a hole transport layer in an inverted perovskite solar cell, it can achieve a photoelectric conversion efficiency of >22% for both forward and reverse scans without doping. This significantly improves the short-circuit current of perovskite solar cells and has broad application prospects.

[0008] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A compound based on an imino structure, the compound having the following chemical structural formula:

[0009] ;

[0010] Wherein, R1 is any one of hydrogen, halogen, alkyl, or alkoxy; R2 is any one of hydrogen, halogen, alkyl, or alkoxy; n = 2~4; It can be either a single bond or a double bond.

[0011] Furthermore, R1 and R2 are each independently selected from H, Br, -CH3, and -OCH3.

[0012] Furthermore, the compound is selected from any of the following chemical structures:

[0013] .

[0014] This invention also discloses a method for preparing a compound based on an imino structure, the method comprising the following steps:

[0015] S1. Under the action of sodium hydride, compound 1 based on imino reacts with diethyl bromoalkyl phosphate to generate diethyl alkylphosphonate based on imino structure.

[0016] S2. Under inert gas conditions, the alkylphosphonate diethyl ester with an imino structure obtained in step S1 reacts with trimethylbromosilane and methanol to generate the target product, a compound with an imino structure.

[0017] In step S1, the alkyl group in the diethyl brominated alkyl phosphate is any one of C2 to C4, preferably any one of C2 and C4.

[0018] Furthermore, in step S1, the molar ratio of imino-based compound 1, diethyl brominated alkyl phosphate, and sodium hydride is 1:(1~5):(1~2.5); preferably 1:(1~2):(1.2~1.5), more preferably 1:(1~1.5):(1.2~1.5).

[0019] Furthermore, in step S2, the molar ratio of alkylphosphonate diethyl ester based on the imino structure and trimethylbromosilane is 1:(1~10), preferably 1:(2~5), and more preferably 1:(3~4).

[0020] Furthermore, in step S2, the mass ratio of diethyl alkylphosphonate based on the imino structure to methanol is 1:(5~10).

[0021] Furthermore, in step S1, the reaction temperature is 20~50℃ and the reaction time is 2~10 hours; preferably, the reaction temperature is 20~30℃ and the reaction time is 2~5 hours.

[0022] Furthermore, in step S2, the reaction temperature is 40~80℃ and the reaction time is 2~10 hours; preferably, the reaction temperature is 50~70℃ and the reaction time is 2~5 hours; more preferably, the reaction temperature is 50~60℃ and the reaction time is 3~4 hours.

[0023] Furthermore, in step S1, the solvent is at least one of tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), and dioxane; preferably DMSO.

[0024] Furthermore, in step S2, the solvent is at least one selected from dichloromethane, dichloroethane, toluene, dioxane, and methanol, preferably dichloromethane or dichloroethane, and more preferably dichloroethane.

[0025] Furthermore, compound 1 based on imino is either a compound based on iminostilbene or a compound based on iminodibenzyl.

[0026] Furthermore, the chemical structural formula of the iminostilbene-based compound is as follows: ;

[0027] The chemical structural formula of the compound based on iminodibenzyl is: ;

[0028] Wherein, R1 is any one of hydrogen, halogen, alkyl, or alkoxy; R2 is any one of hydrogen, halogen, alkyl, or alkoxy.

[0029] Furthermore, compounds based on iminostilbene ( The preparation method of ) includes the following steps:

[0030] (1) A 5-substituted indole compound and a para-substituted bromobenzene compound react in the presence of cuprous iodide and potassium carbonate at a reaction temperature of 140-165°C for 2-10 hours to generate a compound based on 1-phenylindole. The preferred reaction temperature is 150-165°C and the reaction time is 4-8 hours; more preferably, the reaction temperature is 160-165°C and the reaction time is 5-6 hours.

[0031] (2) The 1-phenylindole-based compound obtained in step (1) is reacted with a strong protic acid at a reaction temperature of 70-150°C for 5-20 hours to generate an iminostilbene-based compound. The preferred reaction temperature is 80-120°C and the reaction time is 8-14 hours; more preferably, the reaction temperature is 90-100°C and the reaction time is 10-12 hours.

[0032] Furthermore, in step (2), the strong protic acid is at least one of chlorosulfonic acid, fluorosulfonic acid, trifluoromethanesulfonic acid, and sulfuric acid, preferably trifluoromethanesulfonic acid.

[0033] Further, in step (1), the molar ratio of the 5-substituted indole compound, the para-substituted bromobenzene compound, the cuprous iodide and the potassium carbonate is 1:(1~10):(0.1~1.0):(1~5); preferably, the molar ratio of the 5-substituted indole compound, the para-substituted bromobenzene compound, the cuprous iodide and the potassium carbonate is 1:(1.5~3):(0.1~0.2):(1~2); more preferably, the molar ratio of the 5-substituted indole compound, the para-substituted bromobenzene compound, the cuprous iodide and the potassium carbonate is 1:(2~2.4):(0.1~0.2):(1~1.1).

[0034] Furthermore, in step (2), the molar ratio of the 1-phenylindole-based compound to the strong protic acid is 1:(1~10), preferably 1:(3~6); more preferably 1:(4~5).

[0035] Furthermore, in step (1), the 5-substituted indole compound is any one of indole, 5-bromoindole, 5-methylindole, and 5-methoxyindole; the para-substituted bromobenzene compound is any one of bromobenzene, p-dibromobenzene, p-methylbromobenzene, and p-methoxybromobenzene.

[0036] Furthermore, in step (1), the solvent is at least one of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), preferably DMSO.

[0037] Furthermore, in step (2), the solvent is at least one of chlorobenzene, bromobenzene, dichlorobenzene, and xylene, preferably chlorobenzene.

[0038] This invention also discloses the application of a compound based on an imino structure, which is used in perovskite solar cell devices.

[0039] Furthermore, this compound is applied as a hole transport layer in perovskite solar cell devices.

[0040] Furthermore, the structure of a perovskite solar cell, from top to bottom, is glass / hole transport layer / perovskite / C60 / BCP / Cu.

[0041] Furthermore, the glass is either FTO glass or ITO glass, with FTO glass being preferred.

[0042] Furthermore, the hole transport layer is a compound based on an imino structure provided by this invention.

[0043] Furthermore, BCP is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, a hole-blocking material located between the back / top electrode and the electron transport layer.

[0044] Furthermore, the fabrication of perovskite solar cell devices includes the following steps:

[0045] 1) Pre-treatment cleaning of FTO glass;

[0046] 2) Spin-coat a layer of ethanol solution of hole transport material onto the FTO glass that has been cleaned in step 1), and then anneal it.

[0047] 3) Spin-coat the perovskite solution onto the surface of the hole transport material and anneal it;

[0048] 4) C60, BCP and Cu are deposited on the perovskite surface to obtain perovskite solar cell devices.

[0049] Furthermore, in step 1), the pretreatment cleaning includes: ultrasonic cleaning with cleaning agent, deionized water, ethanol, and acetone for 20 min each, followed by drying with nitrogen.

[0050] Furthermore, in step 2), the concentration of the ethanol solution of the hole transport material is 0.3~1.0 mg / mL, and the amount used is 100~150 μL; the spin coating speed is 3000 rpm~5000 rpm.

[0051] Furthermore, in step 2), the annealing temperature is 100~120℃, and the annealing treatment is 10 min.

[0052] Furthermore, in step 3), the annealing temperature is 100~120℃, and the annealing treatment is 10 min.

[0053] Furthermore, in step 4), C60 with a thickness of 10-20 nm, BCP with a thickness of 5-10 nm, and Cu with a thickness of 80 nm are deposited by vapor deposition.

[0054] Furthermore, in step 4), the effective area of ​​the perovskite solar cell device is obtained to be 0.09 cm². 2 .

[0055] The beneficial effects of this invention are:

[0056] (1) The imino-based compound provided by this invention is a self-assembled monolayer hole transport material. It has iminostilbene and iminodibenzyl as the parent core with a rigid conjugated large plane of a seven-membered ring, replacing the traditional carbazole as the parent core hole transport layer material. This endows the molecule with good hole transport performance. The resulting hole transport material has good solubility and film-forming properties. By utilizing its interface passivation properties, it reduces energy loss at the interface and improves battery efficiency. With alkyl phosphate as the anchoring group, it achieves complete coverage and bonding of the hole transport material on the substrate surface.

[0057] (2) The imino-based compound provided by this invention is applied to perovskite solar cells for the first time, providing a way to prepare the hole transport layer in perovskite solar cell devices.

[0058] (3) The preparation method of the compound based on the imino structure provided by the present invention adopts a simplified synthesis step and synthesizes self-assembled monolayer hole transport materials based on iminostilbene, iminodibenzyl and their derivatives at low cost. The laboratory calculated material cost is 500 yuan / g, which is much lower than the currently widely used PTAA (2000 yuan / g).

[0059] (4) When the imino-based compound provided by the present invention is used as the hole transport layer of an inverted perovskite solar cell, it can achieve a photoelectric conversion efficiency of >22% without doping, and at the same time greatly improves the lifetime and stability of the perovskite solar cell, which is expected to help the perovskite solar cell achieve industrialization. Attached Figure Description

[0060] Figure 1 The mass spectrum of 1-phenylindole prepared in Example 1;

[0061] Figure 2 The 1H NMR spectrum of 1-phenylindole prepared in Example 1;

[0062] Figure 3 The carbon NMR spectrum of 1-phenylindole prepared in Example 1;

[0063] Figure 4 The mass spectrum of the iminostilbene prepared in Example 1;

[0064] Figure 5 The 1H NMR spectrum of the iminostilbene prepared in Example 1;

[0065] Figure 6 The carbon NMR spectrum of the iminostilbene prepared in Example 1;

[0066] Figure 7 The 1H NMR spectrum of diethyl iminostilbene ethylphosphonate prepared in Example 1;

[0067] Figure 8 The carbon NMR spectrum of diethyl iminostilbene ethylphosphonate prepared in Example 1;

[0068] Figure 9 The mass spectrum of iminostilbene ethylphosphonic acid (2PABZ) prepared in Example 1 is shown below.

[0069] Figure 10 The 1H NMR spectrum of iminostilbene ethylphosphonic acid (2PABZ) prepared in Example 1;

[0070] Figure 11 The carbon NMR spectrum of iminostilbene ethylphosphonic acid (2PABZ) prepared in Example 1;

[0071] Figure 12 The mass spectrum of diethyl iminodibenzylethylphosphonate prepared in Example 2;

[0072] Figure 13 The mass spectrum of iminodibenzylethylphosphonic acid (DBADZ) prepared in Example 2 is shown below.

[0073] Figure 14 The 1H NMR spectrum of iminodibenzylethylphosphonic acid (DBADZ) prepared in Example 2;

[0074] Figure 15 The carbon NMR spectrum of iminodibenzylethylphosphonic acid (DBADZ) prepared in Example 2;

[0075] Figure 16 The liquid chromatography chromatogram of iminodibenzylethylphosphonic acid (DBADZ) prepared in Example 2;

[0076] Figure 17 JV curve of 2PABZ prepared in this invention as an undoped hole transport material for perovskite solar cell devices.

[0077] Figure 18 JV curve of DBADZ prepared in this invention as an undoped hole transport material for perovskite solar cell devices;

[0078] Figure 19 This is a schematic diagram of the perovskite solar cell device prepared according to the present invention. Detailed Implementation

[0079] The specific embodiments of the present invention will be described in detail below. The present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed.

[0080] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used is for describing particular embodiments only and is not intended to limit the invention.

[0081] A compound based on an imino structure, having the following chemical structural formula:

[0082] ;

[0083] Wherein, R1 is any one of hydrogen, halogen, alkyl, and alkoxy; R2 is any one of hydrogen, halogen, alkyl, and alkoxy; n=2~4; It can be either a single bond or a double bond.

[0084] Specifically, R1 and R2 are each independently selected from H, Br, -CH3, and -OCH3.

[0085] Specifically, the compound is selected from any of the following chemical structures:

[0086] .

[0087] A method for preparing a compound based on an imino structure, the method comprising the following steps:

[0088] S1. Under the action of sodium hydride, compound 1 based on imino reacts with diethyl brominated alkyl phosphate to generate diethyl alkylphosphonate based on imino structure.

[0089] S2. Under inert gas conditions, the alkylphosphonate diethyl ester with an imino structure obtained in step S1 reacts with trimethylbromosilane and methanol to generate the target product, a compound with an imino structure.

[0090] In step S1, the alkyl group in the diethyl brominated alkyl phosphate is any one of C2 to C4, preferably any one of C2 and C4.

[0091] More specifically, the synthetic route is as follows:

[0092] ,

[0093] Wherein, R1 = any one of H, halogen, alkyl, and alkoxy; R2 = any one of H, halogen, alkyl, and alkoxy; n = 2~4; It can be either a single bond or a double bond.

[0094] More specifically, imino-based compound 1 ( ) is either a compound based on iminostilbene or a compound based on iminodibenzyl; wherein the chemical structural formula of the compound based on iminostilbene is: The chemical structural formula of the compound based on iminodibenzyl is as follows: Wherein, R1 is any one of hydrogen, halogen, alkyl, or alkoxy; and R2 is any one of hydrogen, halogen, alkyl, or alkoxy.

[0095] Specifically, in step S1, the molar ratio of imino-based compound 1, diethyl brominated alkyl phosphate, and sodium hydride is 1:(1~5):(1~2.5); preferably 1:(1~2):(1.2~1.5), and more preferably 1:(1~1.5):(1.2~1.5).

[0096] Specifically, in step S2, the molar ratio of alkylphosphonate diethyl ester based on the imino structure to trimethylbromosilane is 1:(1~10), preferably 1:(2~5), and more preferably 1:(3~4); in step S2, the mass ratio of alkylphosphonate diethyl ester based on the imino structure to methanol is 1:(5~10).

[0097] Specifically, in step S1, the reaction temperature is 20~50℃ and the reaction time is 2~10 hours; preferably, the reaction temperature is 20~30℃ and the reaction time is 2~5 hours.

[0098] Specifically, in step S2, the reaction temperature is 40~80℃ and the reaction time is 2~10 hours; preferably, the reaction temperature is 50~70℃ and the reaction time is 2~5 hours; more preferably, the reaction temperature is 50~60℃ and the reaction time is 3~4 hours.

[0099] Specifically, in step S1, the solvent is at least one of tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), and dioxane; preferably DMSO.

[0100] Specifically, in step S2, the solvent is at least one of dichloromethane, dichloroethane, toluene, dioxane, and methanol, preferably dichloromethane or dichloroethane, and more preferably dichloroethane.

[0101] More specifically, compounds based on iminostilbene ( It needs to be obtained through the following preparation method, which includes the following steps:

[0102] (1) A 5-substituted indole compound and a para-substituted bromobenzene compound react in the presence of cuprous iodide and potassium carbonate at a reaction temperature of 140-165°C for 2-10 hours to generate a compound based on 1-phenylindole. The preferred reaction temperature is 150-165°C and the reaction time is 4-8 hours; more preferably, the reaction temperature is 160-165°C and the reaction time is 5-6 hours.

[0103] (2) The 1-phenylindole-based compound obtained in step (1) is reacted with a strong protic acid at a reaction temperature of 70-150°C for 5-20 hours to generate an iminostilbene-based compound. The preferred reaction temperature is 80-120°C and the reaction time is 8-14 hours; more preferably, the reaction temperature is 90-100°C and the reaction time is 10-12 hours.

[0104] Specifically, in step (2), the strong protic acid is at least one of chlorosulfonic acid, fluorosulfonic acid, trifluoromethylsulfonic acid, and sulfuric acid, preferably trifluoromethylsulfonic acid.

[0105] Specifically, in step (1), the molar ratio of 5-substituted indole compound, para-substituted bromobenzene compound, cuprous iodide and potassium carbonate is 1:(1~10):(0.1~1.0):(1~5); preferably, the molar ratio of 5-substituted indole compound, para-substituted bromobenzene compound, cuprous iodide and potassium carbonate is 1:(1.5~3):(0.1~0.2):(1~2), more preferably, the molar ratio of 5-substituted indole compound, para-substituted bromobenzene compound, cuprous iodide and potassium carbonate is 1:(2~2.4):(0.1~0.2):(1~1.1).

[0106] Specifically, in step (2), the molar ratio of the 1-phenylindole-based compound to the strong protic acid is 1:(1~10), preferably 1:(3~6); more preferably 1:(4~5).

[0107] More specifically, in step (1), the 5-substituted indole compound is any one of indole, 5-bromoindole, 5-methylindole, and 5-methoxyindole; the para-substituted bromobenzene compound is any one of bromobenzene, p-dibromobenzene, p-methylbromobenzene, and p-methoxybromobenzene.

[0108] Specifically, in step (1), the solvent is at least one of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), preferably DMSO.

[0109] Specifically, in step (2), the solvent is at least one of chlorobenzene, bromobenzene, dichlorobenzene, and xylene, preferably chlorobenzene.

[0110] More specifically, compounds based on iminostilbene ( The synthetic route for ) is as follows:

[0111] Wherein, R1 = any one of H, halogen, alkyl, or alkoxy; R2 = any one of H, halogen, alkyl, or alkoxy; n = 2~4.

[0112] An application of a compound based on an imino structure is described. This compound is used as a hole transport layer in a perovskite solar cell device. A schematic diagram of the perovskite solar cell device is shown below. Figure 19 As shown in the figure; the hole transport layer (HTL) is provided by the imino-based compound provided by the present invention, the bottom electrode refers to ITO glass or FTO glass, the perovskite layer refers to the film obtained after spin coating of perovskite solution, the electron transport layer (ETL) refers to C60, and the back / top electrode refers to Cu.

[0113] The structure of a perovskite solar cell device, from bottom to top, is denoted as glass / hole transport layer / perovskite / C60 / BCP / Cu.

[0114] Specifically, the glass is either FTO glass or ITO glass, with FTO glass being preferred.

[0115] Specifically, the hole transport layer is a compound based on an imino structure provided by this invention.

[0116] Specifically, BCP is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, a hole-blocking material located between the back / top electrode and the electron transport layer.

[0117] Specifically, the fabrication of perovskite solar cell devices includes the following steps:

[0118] 1) Pretreatment and cleaning of FTO glass: FTO glass was ultrasonically cleaned for 20 min each time with cleaning agent, deionized water, ethanol and acetone, and then dried with nitrogen.

[0119] 2) Spin-coat a layer of hole transport material ethanol solution onto the FTO glass cleaned in step 1), and anneal it; wherein, the concentration of the hole transport material ethanol solution is 0.3~1.0mg / mL, the amount is 100~150μL; the spin-coating speed is 3000 rpm~5000 rpm; the annealing temperature is 100~120℃, and the annealing treatment is 10 min.

[0120] 3) Spin-coat the perovskite solution onto the surface of the hole transport material and anneal it; the annealing temperature is 100~120℃ and the annealing time is 10 min.

[0121] 4) C60 (10-20 nm), BCP (5-10 nm), and Cu (80 nm) were deposited on the perovskite surface to obtain a perovskite solar cell device with an effective area of ​​0.09 cm². 2 .

[0122] It should be noted that the compound based on the imino structure provided by this invention is used as a hole transport layer in perovskite solar cell devices. The perovskite solar cell devices are prepared using the most traditional preparation method. The hole transport layer mentioned in this invention uses an undoped compound based on the imino structure, and no other additives are added to the hole transport layer.

[0123] Specifically, in this embodiment of the invention, R1=R2, and n is any number between 2 and 4; wherein R1=R2 are selected from any one of H, Br, -CH3, and -OCH3, the preparation method of the hole transport material of iminostilbene is described, which does not limit the technology of the present invention. Here, taking R1=R2=H and n=2 as an example, the preparation method of the hole transport material of iminostilbene is described in detail, and the final compound is denoted as 2PABZ, whose chemical structural formula is as follows:

[0124] .

[0125] More specifically, the preparation method of 2PABZ in this embodiment of the invention includes the following steps:

[0126] (1) Preparation of 1-phenylindole: Indole, cuprous iodide, potassium carbonate, bromobenzene and solvent were added to a three-necked flask in sequence, and the reaction was carried out at 140~165℃ for 2~10 hours.

[0127] Post-processing: After the reaction is complete, the reaction solution is allowed to cool naturally to room temperature. The organic phase is then washed with water, extracted, and dried with anhydrous sodium sulfate. The solvent is removed by rotary evaporation. The solution is purified by toluene column chromatography. After desolventizing the eluent under reduced pressure, 1-phenylindole is obtained.

[0128] Specifically, the extraction solvent is at least one of dichloromethane and ethyl acetate, with ethyl acetate being the preferred extraction solvent.

[0129] (2) Preparation of iminostilbene: Add strong protic acid and solvent to a three-necked flask in sequence, stir evenly at room temperature, add 1-phenylindole, heat to 70~150℃ and keep warm for 5~20 hours.

[0130] Post-processing: After the reaction is complete, the reaction solution is allowed to cool naturally to room temperature. The solution is then quenched and extracted using a saturated sodium bicarbonate aqueous solution. The organic phase is purified by column chromatography. The eluent is removed under reduced pressure to remove the solvent. After removal of the solvent, the solution is recrystallized twice to obtain iminostilbene.

[0131] Specifically, the extraction solvents are dichloromethane and ethyl acetate, with ethyl acetate being preferred.

[0132] Specifically, the recrystallization solvent is at least one of toluene, ethyl acetate, petroleum ether, and n-heptane, with a mixed solvent of toluene and petroleum ether being preferred.

[0133] (3) Preparation of diethyl iminostilbene ethylphosphonate: Add NaH and solvent to a three-necked flask in sequence, start stirring, add DMSO solution of iminostilbene dropwise, and keep warm at 20~50℃ for 1h after the addition is complete; after the warming is complete, add diethyl bromide ethyl phosphate dropwise, and keep warm for 1~9 hours after the addition is complete.

[0134] Post-processing: After the reaction was completed, the reaction solution was naturally cooled to room temperature, washed with water, extracted with organic solvent, and the organic phase was extracted by drying with anhydrous sodium sulfate. The solvent was removed by rotary evaporation. Petroleum ether and ethyl acetate were used as eluents for column chromatography purification, with a volume ratio of petroleum ether to ethyl acetate of 3:1. After desolventizing the eluent under reduced pressure, diethyl iminostilbene ethylphosphonate was obtained by recrystallization.

[0135] Specifically, the extraction solvents are dichloromethane and ethyl acetate, with ethyl acetate being preferred.

[0136] Specifically, the recrystallization solvent is at least one of toluene, ethyl acetate, petroleum ether, and n-heptane, with a preferred recrystallization solvent being a mixture of toluene and petroleum ether.

[0137] (4) Preparation of iminostilbene ethylphosphonic acid: Under inert gas conditions, diethyl iminostilbene ethylphosphonic acid and solvent were added to a three-necked flask in sequence. Trimethylbromosilane was added while stirring. The reaction was carried out at 40~80℃ for 2~10 hours. Then methanol was added and stirring was continued for 1~3 hours to achieve quenching reaction. The target product iminostilbene ethylphosphonic acid was generated after the reaction was completed, which was denoted as 2PABZ.

[0138] Specifically, in step S4, the mass ratio of diethyl iminostilbene ethylphosphonate, solvent, and methanol is 1:(5~15):(5~10), preferably 1:(7~9):(6~8).

[0139] Post-processing: After the reaction is complete, the reaction solution is transferred to a single-necked flask. The solvent in the reaction solution is removed by rotary evaporation to obtain crude product 1. Crude product 1 is then dissolved in ethyl acetate, stirred, filtered, and the filtrate is desolventized to obtain crude product 2. Crude product 2 is then purified by recrystallization to obtain the target product.

[0140] Specifically, the amount of ethyl acetate added to dissolve crude product 1 is as follows: the mass ratio of ethyl acetate to crude product 1 is (10~15):1.

[0141] Specifically, the recrystallization solvent can be selected from at least one of methanol, dichloromethane, ethyl acetate, toluene, and petroleum ether, with ethyl acetate and petroleum ether being preferred.

[0142] More specifically, the amount of recrystallization solvent added is as follows: the mass ratio of ethyl acetate to crude product 2 is (2~5):1, preferably (2~3):1; the mass ratio of petroleum ether to crude product 2 is (3~9):1, preferably (5~6).

[0143] More specifically, the synthetic route for 2PABZ is shown below:

[0144] .

[0145] Specifically, in this embodiment of the invention, R1=R2, and n is any number between 2 and 4; wherein R1=R2 are selected from any one of H, Br, -CH3, and -OCH3, the preparation method of the hole transport material of iminodibenzyl is described, which does not limit the technology of the present invention. Here, taking R1=R2=H and n=2 as an example, the preparation method of the hole transport material of iminodibenzyl is described in detail, and the final compound is denoted as DBADZ, and its chemical structural formula is as follows:

[0146] .

[0147] More specifically, the preparation method of DBADZ in this embodiment of the invention includes the following steps:

[0148] (1) Preparation of diethyl iminodibenzyl ethylphosphonate: NaH and solvent were added to a three-necked flask in sequence, stirring was started, and DMSO solution of diiminodibenzyl was added dropwise. After the addition was completed, the temperature was kept at 20~50℃ for 1h. After the temperature was completed, diethyl bromide phosphate was added dropwise. After the addition was completed, the reaction was kept at 20~50℃ for 1~9 hours.

[0149] Post-processing: After the reaction was completed, the reaction solution was naturally cooled to room temperature, washed with water, extracted with organic solvent, dried with anhydrous sodium sulfate to extract the organic phase, and the solvent was removed by rotary evaporation; column chromatography was used as the eluent to purify the solution, with a volume ratio of petroleum ether to ethyl acetate of 3:1; after desolventizing the eluent under reduced pressure, diethyl iminobisbenzylethylphosphonate was obtained.

[0150] Specifically, the extraction solvents are dichloromethane and ethyl acetate, with ethyl acetate being preferred.

[0151] (2) Preparation of iminodibenzylethylphosphonic acid: Under inert gas conditions, diethyl iminodibenzylethylphosphonic acid and solvent were added to a three-necked flask in sequence. Trimethylbromosilane was added while stirring. The reaction was carried out at 40~80℃ for 2~10 hours. Then methanol was added and stirring was continued for 1~3 hours to achieve quenching reaction. The target product iminodibenzylethylphosphonic acid, denoted as DBADZ, was generated after the reaction was completed.

[0152] Specifically, in step S4, the mass ratio of diethyl iminodibenzyl ethylphosphonate, solvent, and methanol is 1:(3~10):(2~6), preferably 1:(5~6):(4~5).

[0153] Post-processing: After the reaction is complete, the reaction solution is transferred to a single-necked flask. The solvent in the reaction solution is removed by rotary evaporation to obtain crude product 1. Crude product 1 is then dissolved in ethyl acetate, stirred, filtered, and the filtrate is desolventized to obtain crude product 2. Crude product 2 is then purified by recrystallization to obtain the target product.

[0154] Specifically, the amount of ethyl acetate added to dissolve crude product 1 is as follows: the mass ratio of ethyl acetate to crude product 1 is (10~15):1.

[0155] Specifically, the recrystallization solvent can be selected from at least one of methanol, dichloromethane, ethyl acetate, toluene, and petroleum ether, with ethyl acetate and petroleum ether being preferred.

[0156] More specifically, the amount of recrystallization solvent added is as follows: the mass ratio of ethyl acetate to crude product 2 is (2~5):1, preferably (2~3):1; the mass ratio of petroleum ether to crude product 2 is (3~9):1, preferably (5~6).

[0157] More specifically, the synthetic route for DBADZ is shown below:

[0158] .

[0159] The purity levels mentioned in the embodiments and comparative examples of this invention were obtained by liquid chromatography.

[0160] Example 1

[0161] Preparation of iminostilbene ethylphosphonic acid (2PABZ), a hole transport material based on an imino structure, is described below via the synthetic route:

[0162] .

[0163] Specifically, the following steps are included:

[0164] (1) Preparation of 1-phenylindole: 58.6 g (0.50 mol) indole, 9.5 g (0.05 mol) cuprous iodide, 76.0 g (0.55 mol) potassium carbonate, 188.4 g (1.2 mol) bromobenzene and 290.0 g DMSO solvent were added to a 1.0 L three-necked flask in sequence, and the temperature was raised to 160~165℃ and kept at the temperature for 5 hours.

[0165] Post-processing: After the reaction was completed, the reaction solution was allowed to cool naturally to room temperature (20-25°C). 200.0 g of water was added to quench the reaction, followed by extraction with 300.0 g of ethyl acetate. The organic phase was dried over anhydrous sodium sulfate, and the solvent was removed by rotary evaporation to obtain the crude product. The crude product was dissolved in toluene and purified by column chromatography using toluene as the eluent. The collected eluent was desolventized under reduced pressure to obtain 1-phenylindole. The purity of the 1-phenylindole obtained in this example was 98.81%, and the yield was 78.5%. The mass spectrum, 1H NMR spectrum, and 1C NMR spectrum of the 1-phenylindole obtained in this example are shown below. Figure 1-3 As shown. 1 H NMR (400 MHz, DMSO- d 6 ): δ7.640-7.667(d,1H),7.567-7.575(d,1H),7.489-7.542(m,5H),7.316-7.359(m,1H), 7.097-7.187(m,2H), 6.679-6.689(dd,1H) ppm. 13 C (101 MHz, DMSO- d 6 ): δ139.691, 136.676,130.309, 129.696, 128.939, 126.888, 124.330, 122.845, 121.522,120.804,110.876, 104.101ppm.

[0166] (2) Preparation of iminostilbene: 90.0 g (0.60 mol) trifluoromethanesulfonic acid and 170.0 g chlorobenzene solvent were added to a 1.0 L three-necked flask in sequence. After stirring evenly at room temperature, 29.3 g (0.15 mol) 1-phenylindole was added and the temperature was raised to 90~95℃ and kept at that temperature for 12 hours.

[0167] Post-processing: After the reaction, the reaction solution was allowed to cool naturally to room temperature. A saturated sodium bicarbonate aqueous solution was added to the reaction solution to quench the reaction. Extraction was performed using 300g of ethyl acetate, followed by desolventizing the organic phase under reduced pressure to obtain the crude product. The crude product was dissolved in toluene and purified by column chromatography using toluene as the eluent. Desolventizing the eluent under reduced pressure followed by recrystallization twice using a mixed solvent of toluene and petroleum ether to obtain iminostilbene. The iminostilbene obtained in this example had a purity of 97% and a yield of 62%. The mass spectrum, 1H NMR spectrum, and 1C NMR spectrum of the iminostilbene obtained in this example are shown below. Figure 4-6 As shown. 1 H NMR (400 MHz, DMSO-) d 6 ): δ6.933-6.975(td,2H),6.913(s,1H),6.724-7.747(dd,2H),6.657-6.697(td,2H),6.588-6.611(dd,2H),6.067(s,1H)ppm. 13 C (101 MHz, DMSO- d 6 ): δ150.030, 132.600, 130.971, 130.089, 129.572, 122.442, 119.587ppm.

[0168] (3) Preparation of diethyl iminostilbene ethylphosphonate: 0.96 g (0.024 mol) NaH and 10.0 g DMSO solvent were added to a 500 mL three-necked flask. Stirring was started, and at 20~30℃, DMSO solution of iminostilbene (3.8 g (0.02 mol) 2PABZ-B dissolved in 10.0 g DMSO) was added dropwise. After the addition was completed, the temperature was kept at 20~30℃ for 1 h. After the temperature was kept at 20~30℃, diethyl bromide phosphate was added dropwise. After the addition was completed, the reaction was kept at 20~30℃ for 3 h.

[0169] Post-processing: After the reaction was completed, the reaction solution was allowed to cool naturally to room temperature. 200.0 g of water was added to quench the reaction, followed by extraction with 300.0 g of ethyl acetate. The organic phase was then dried over anhydrous sodium sulfate and the solvent was removed by rotary evaporation to obtain the crude product. The crude product was purified by column chromatography using petroleum ether and ethyl acetate as eluents, with a volume ratio of 3:1. After desolventizing the eluents under reduced pressure, a mixture of toluene and petroleum ether was added, and the product was recrystallized to obtain diethyl iminostilbene ethylphosphonate. The purity of diethyl iminostilbene ethylphosphonate obtained in this example was 97%, and the yield was 55.5%. The 1H and 1C NMR spectra of diethyl iminostilbene ethylphosphonate obtained in this example are shown below. Figure 7 and 8As shown. 1 H NMR (400 MHz, DMSO-) d 6 ): δ7.242-7.284(td,2H),7.072-7.095(dd,2H),7.026-7.046(d,2H),6.960 -6.999(td,2H),6.718(s,2H),3.853-4.011(m,6H),1.828-1.908(m,2H), 1.134-1.169(t,6H)ppm. 13 C (101 MHz, DMSO- d 6 ): δ150.184, 133.893, 132.408, 129.591,124.081, 120.660, 61.660, 61.603, 44.422, 25.678,24.317, 16.786, 16.728ppm.

[0170] (4) Preparation of iminostilbene ethylphosphonic acid: Under inert gas conditions, 5.2 g (0.015 mol) of diethyl iminostilbene ethylphosphonic acid and 40.0 g of dichloroethane were added to a 250 mL three-necked flask. 6.9 g (0.045 mol) of trimethylbromosilane was added while stirring. The reaction was carried out at 55~60℃ for 4 hours. Then, 50.0 g of methanol was added and stirring was continued for 1.5 hours to achieve the quenching reaction.

[0171] Post-processing: After the reaction was complete, the reaction solution was transferred to a single-necked flask. The solvent in the reaction solution was removed by rotary evaporation to obtain crude product 1. 33.0 g of ethyl acetate was added to dissolve crude product 1, and the mixture was stirred at 60-65°C until completely dissolved. 55 g of petroleum ether was added, and a solid precipitated. After filtration, crude product 2 was obtained. Crude product 2 was purified by recrystallization three times using ethyl acetate and petroleum ether to obtain the target product, iminostilbene ethylphosphonic acid, denoted as 2PABZ. The purity of iminostilbene ethylphosphonic acid obtained in this example was 98%, and the yield was 52.5%. The mass spectrum, 1H NMR spectrum, and 1C NMR spectrum of iminostilbene ethylphosphonic acid (2PABZ) obtained in this example are shown below. Figure 9-11 As shown. 1 H NMR (400 MHz, DMSO- d 6): δ7.312-7.355(td,2H),7.208-7.228(d,2H),7.167-7.191(dd,2H),7.080 -7.120(td,2H),6.817(s,2H),3.930-3.990(m,2H),1.873-1.960(m,2H)ppm. 13 C (101 MHz, DMSO- d 6 ): δ190.452, 133.865, 132.465,129.600, 123.996, 120.737, 45.255, 28.706, ppm.

[0172] Example 2

[0173] Preparation of iminodibenzylethylphosphonic acid (DBADZ), a hole transport material based on an imino structure. The synthetic route of DBADZ is shown below:

[0174] .

[0175] Specifically, the following steps are included:

[0176] (1) Preparation of diethyl iminodibenzyl ethylphosphonate: 6.0 g (0.15 mol) NaH and 40.0 g DMSO solvent were added to a 500 mL three-necked flask. Stirring was started, and a DMSO solution of diethyl iminodibenzyl (19.5 g (0.1 mol) diethyl iminodibenzyl dissolved in 60 g DMSO) was added dropwise. After the addition was completed, the mixture was kept at 20~30℃ for 1 h. After the mixture was kept at 20~30℃, 36.7 g (0.15 mol) diethyl bromide phosphate was added dropwise. After the addition was completed, the mixture was kept at 20~30℃ for 3 h.

[0177] Post-processing: After the reaction was completed, the reaction solution was allowed to cool naturally to room temperature. 200.0 g of water was added to quench the reaction, followed by extraction with 300.0 g of ethyl acetate. The organic phase was extracted by drying with anhydrous sodium sulfate, and the solvent was removed by rotary evaporation to obtain the crude product. The crude product was purified by column chromatography using petroleum ether and ethyl acetate as eluents, with a volume ratio of 3:1. After desolventizing the eluents under reduced pressure, a yellow oily liquid was obtained, which was diethyl iminodibenzylethylphosphonate. The purity of diethyl iminodibenzylethylphosphonate obtained in this example was 95%, and the yield was 65.5%. The mass spectrum of diethyl iminodibenzylethylphosphonate obtained in this example is shown below. Figure 12 As shown.

[0178] (2) Preparation of iminodibenzylethylphosphonic acid: Under inert gas conditions, 12.0 g (0.033 mol) of diethyl iminodibenzylethylphosphonic acid obtained in step (1) and 60.0 g of dichloroethane solvent were added to a 250 mL three-necked flask. 15.4 g (0.099 mol) of trimethylbromosilane was added while stirring. The reaction was kept at 55~60℃ for 4 hours. Then 50.0 g of methanol was added and stirring was continued for 1.5 hours to achieve the quenching reaction.

[0179] Post-processing: After the reaction was complete, the reaction solution was transferred to a single-necked flask. The solvent in the reaction solution was removed by rotary evaporation to obtain crude product 1. 33.0 g of ethyl acetate was added to dissolve crude product 1, and the mixture was stirred at 60-65°C until completely dissolved. 55 g of petroleum ether was added, and a solid precipitated. After filtration, crude product 2 was obtained. Crude product 2 was purified by recrystallization three times using ethyl acetate and petroleum ether to obtain the target product, iminodibenzylethylphosphonic acid, denoted as DBADZ. The iminodibenzylethylphosphonic acid obtained in this example had a purity of 99.7% and a yield of 54.0% as determined by liquid chromatography. The mass spectrum, 1H NMR spectrum, and 1C NMR spectrum of the iminodibenzylethylphosphonic acid (DBADZ) obtained in this example are shown below. Figure 13-15 As shown. 1 H NMR (400 MHz, DMSO- d 6 ): δ7.021-7.122(m,6H),6.860-6.900(td,2H),3.824-3.883(m,2H),3.037(s,4H),1.676-1.7610(m,2H)ppm. 13 C (101 MHz, DMSO- d 6 ): δ148.200, 134.420, 130.252, 126.936,123.036, 120.267, 45.496, 31.993, 28.649, 27.326ppm.

[0180] The liquid chromatogram of iminodibenzylethylphosphonic acid (DBADZ) prepared in Example 2 is shown below. Figure 16 As shown in Table 1 below, the detection data is as follows.

[0181] Table 1. Liquid Chromatography Detection Data from Example 2

[0182]

[0183] Example 3

[0184] The preparation of iminostilbene bromoxyphosphonic acid, a hole transport material based on iminostilbene, was carried out in this embodiment using the same method as in Example 1, except that in step S1, 5-bromoindole was used instead of indole, and p-dibromobenzene was used instead of bromobenzene, ultimately yielding 4,11-dibromoiminostilbene ethylphosphonic acid. The purity was 97.2%, and the yield was 45.2%.

[0185] Example 4

[0186] The preparation of iminostilbene methylphosphonic acid, a hole transport material based on iminostilbene, was carried out in this embodiment using the same method as in Example 1, except that in step S1, 5-methylindole was used instead of indole, and p-methylbenzene was used instead of bromobenzene, ultimately yielding 4,11-dimethyliminostilbene ethylphosphonic acid. The purity was 97.9%, and the yield was 51.1%.

[0187] Example 5

[0188] This embodiment describes the preparation of iminostilbene methoxyphosphonic acid, a hole transport material based on iminostilbene. The method used in this embodiment is the same as in Example 1, except that in step S1, 5-methoxyindole is used instead of indole, and p-methoxybromobenzene is used instead of bromobenzene, ultimately yielding 4,11-dimethoxyiminostilbene ethylphosphonic acid. The purity is 96.5%, and the yield is 55.6%.

[0189] Example 6

[0190] This embodiment describes the preparation of iminostilbene butylphosphonic acid, a hole transport material based on iminostilbene. The method used in this embodiment is the same as in Example 1, except that in step S3, diethyl bromobutyl phosphate is used instead of diethyl bromoethyl phosphate, ultimately yielding iminostilbene butylphosphonic acid. The purity is 98.1%, and the yield is 56.5%.

[0191] Example 7

[0192] The preparation of iminodibenzyl bromide ethylphosphonic acid, a hole transport material based on iminodibenzyl, was carried out in this embodiment using the same method as in Example 1, except that in step (1), 4,11-dibromoiminodibenzyl was used instead of iminodibenzyl, resulting in 4,11-dibromoiminodibenzyl ethylphosphonic acid. The purity was 98.5%, and the yield was 49.8%.

[0193] Example 8

[0194] The preparation of iminodibenzyl bromide ethylphosphonic acid, a hole transport material based on iminodibenzyl, was carried out in this embodiment using the same method as in Example 1, except that in step (1), 4,11-dimethyliminodibenzyl was used instead of iminodibenzyl, resulting in 4,11-dimethyliminodibenzyl ethylphosphonic acid. The purity was 97.4%, and the yield was 50.2%.

[0195] Example 9

[0196] The preparation of iminodibenzyl bromide ethylphosphonic acid, a hole transport material based on iminodibenzyl, was carried out in this embodiment using the same method as in Example 1, except that in step (1), 4,11-dimethoxyiminodibenzyl was used instead of iminodibenzyl, resulting in 4,11-dimethoxyiminodibenzyl ethylphosphonic acid. The purity was 96.4%, and the yield was 41.5%.

[0197] Example 10

[0198] The preparation of iminodibenzyl butylphosphonic acid, a hole transport material based on iminodibenzyl, was carried out in this embodiment using the same method as in Example 1, except that in step (1), diethyl bromobutyl phosphate was used instead of diethyl bromoethyl phosphate, ultimately yielding iminodibenzyl butylphosphonic acid. The purity was 99.2%, and the yield was 55.6%.

[0199] Example 11

[0200] In Example 11, the hole transport material iminostilbene ethylphosphonic acid (2PABZ) prepared in Example 1 is applied to a perovskite solar cell device to fabricate a perovskite solar cell device: FTO / 2PABZ / perovskite / C60 / BCP / Cu. The specific fabrication steps are as follows:

[0201] 1) Pretreatment and cleaning of FTO glass: FTO glass was ultrasonically cleaned for 20 min each time with cleaning agent, deionized water, ethanol and acetone, and then dried with nitrogen.

[0202] 2) Spin-coat a layer of ethanol solution of iminostilbene ethylphosphonic acid (2PABZ) hole transport material prepared in Example 1 onto the FTO glass that has been cleaned in step 1). The concentration of the ethanol solution of the hole transport material is 0.3~1.0 mg / mL and the amount used is 100~150 μL. The spin-coating speed is 3000 rpm~5000 rpm. Anneal at 100~120℃ for 10 min. Then wash off the excess 2PABZ on the surface with ethanol and anneal at 100~120℃ for 10 min.

[0203] 3) Spin-coat the perovskite solution onto the surface of the 2PABZ hole transport material and anneal it at 100~120℃ for 10 min.

[0204] 4) After cooling, C60, BCP, and Cu electrodes are deposited on the surface of the perovskite thin film, respectively. Specifically, 10-20 nm of C60, 5-10 nm of BCP, and 80 nm of Cu electrode are deposited to obtain the perovskite solar cell device. The effective area of ​​the perovskite solar cell device is 0.09 cm². 2 .

[0205] Example 12

[0206] In Example 12, the hole transport material, iminodibenzylethylphosphonic acid (DBADZ), prepared in Example 2, is applied to a perovskite solar cell device to fabricate a perovskite solar cell device: FTO / DBADZ / perovskite / C60 / BCP / Cu. The specific fabrication steps are as follows:

[0207] 1) Pretreatment and cleaning of FTO glass: FTO glass was ultrasonically cleaned for 20 min each time with cleaning agent, deionized water, ethanol and acetone, and then dried with nitrogen.

[0208] 2) Spin-coat a layer of ethanol solution of iminodibenzylethylphosphonic acid (DBADZ) hole transport material prepared in Example 2 onto the FTO glass cleaned in step 1). The concentration of the ethanol solution of the hole transport material is 0.3~1.0 mg / mL, and the amount used is 100~150 μL. The spin-coating speed is 3000 rpm~5000 rpm. Anneal at 100~120℃ for 10 min. Then wash off the excess DBADZ on the surface with ethanol and anneal at 100~120℃ for 10 min.

[0209] 3) Spin-coat the perovskite solution onto the surface of the DBADZ hole transport material and anneal it at 100~120℃ for 10 min.

[0210] 4) After cooling, C60, BCP, and Cu electrodes are deposited on the surface of the perovskite thin film, respectively. Specifically, 10-20 nm of C60, 5-10 nm of BCP, and 80 nm of Cu electrode are deposited to obtain the perovskite solar cell device. The effective area of ​​the perovskite solar cell device is 0.09 cm². 2 .

[0211] Examples 13 to 20

[0212] Examples 13 to 20 respectively use the imino-based compounds prepared in Examples 3 to 10 as hole transport materials and apply them to perovskite solar cell devices to prepare perovskite solar cell devices. The preparation method of the perovskite solar cell devices is the same as that in Example 1.

[0213] Using a xenon lamp solar simulator, the light source intensity was tested at AM 1.5G, 100mW cm⁻¹. -2 The open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency of the perovskite solar cell devices prepared in the examples were tested. The performance test data of the perovskite solar cell devices prepared in Examples 11-20, Comparative Examples 1 and 2 are shown in Table 2. The JV curves of the perovskite solar cell devices in Examples 11 and 12 are shown in Table 2. Figure 17 and 18 As shown.

[0214] Table 2 Performance test data of perovskite solar cell devices prepared in Examples 12-20 and Comparative Examples 1 and 2

[0215]

[0216] As shown in Table 2, the perovskite solar cell devices prepared using the imino-based compounds provided in this invention as hole transport materials exhibit a photoelectric conversion efficiency greater than 22%. This demonstrates that the undoped imino-based compounds provided in this invention, when applied to perovskite solar cells, demonstrate excellent photoelectric performance, providing a framework for the preparation of hole transport layers in perovskite solar cell devices.

[0217] Comparative Example 1

[0218] The preparation of a perovskite solar cell device involves using poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) (molecular weight: 7000~10000, polydispersity: 1.8), a commonly used hole transport material, to prepare a perovskite solar cell device according to the preparation method in Example 11 of this invention. The performance test data of the perovskite solar cell device are shown in Table 1.

[0219] As shown in Table 1, when the commonly used hole transport material poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) is prepared according to the method of this invention without any other additives and applied to the hole transport layer of the perovskite solar cell device, the resulting perovskite solar cell device has a photoelectric conversion efficiency of approximately 20.79% for forward scan and 20.82% for reverse scan. This is because PTAA has poor wettability and the film layer is non-uniform, resulting in low device efficiency.

[0220] Comparative Example 2

[0221] The fabrication of a perovskite solar cell device in this comparative example uses the same method as in Example 11, except that the purity of the 2PABZ material used in the hole transport layer is 90%, which is significantly lower than the purity of the 2PABZ in Example 1. The performance of the perovskite solar cell device obtained in Comparative Example 2 is significantly lower than that in Example 11. This is because the purity of the iminostilbene ethylphosphonic acid prepared in Comparative Example 2 is low, which affects the device performance when used as a hole transport layer in the perovskite solar cell device.

[0222] Comparative Example 3

[0223] The preparation of a hole transport material based on iminostilbene, iminostilbene ethylphosphonic acid (2PABZ), is described in Comparative Example 3 using the same method as in Example 1, except that: in step (1), the reaction temperature is 120°C, which is lower than the temperature set in this invention; the purity of 1-phenylindole obtained in step (1) is 88.5%, and the yield is 35.6%.

[0224] The comparison of the experimental results of Comparative Example 3 and Example 1 shows that the purity and yield of 1-phenylindole are lower than those of Example 1. This is because the low reaction temperature leads to a slow reaction rate and makes it difficult to convert the raw materials.

[0225] Comparative Example 4

[0226] The preparation of a hole transport material based on iminostilbene, iminostilbene ethylphosphonic acid (2PABZ), was carried out in this comparative example using the same method as in Example 1, except that: in step (1), the reaction temperature was 180°C, which is higher than the temperature set in this invention; the purity of 1-phenylindole obtained in step (1) was 92.9%, and the yield was 52.0%.

[0227] The comparison of the experimental results of Comparative Example 4 and Example 1 shows that the purity and yield of 1-phenylindole are lower than those of Example 1. This is because when the temperature is 180°C, which is significantly higher than the boiling point of bromobenzene, the bromobenzene raw material will be lost due to volatilization during the reaction, affecting the smooth progress of the reaction and thus affecting the yield and purity of the reaction.

[0228] Comparative Example 5

[0229] The preparation of an iminostilbene-based hole transport material, iminostilbene ethylphosphonic acid (2PABZ), was carried out in this comparative example using the same method as in Example 1, except that in step (2), acetic acid was used instead of the strong protic acid trifluoromethanesulfonic acid, and the reaction was not carried out.

[0230] Comparing the experimental results of Comparative Example 5 and Example 1, it can be seen that when acetic acid is used instead of the strong protic acid trifluoromethanesulfonic acid, the reaction phenomenon does not change. This is because acetic acid is a weak protic acid, not the strong protic acid set in this invention, which would make the reaction difficult to proceed normally.

[0231] Comparative Example 6

[0232] The preparation of iminostilbene-based hole transport material iminostilbene ethylphosphonic acid (2PABZ) was carried out in this comparative example using the same method as in Example 1, except that the reaction temperature in step (2) was 110°C, which is higher than the temperature set in this invention. The iminostilbene obtained in step (2) had a purity of 82.5% and a yield of 33.5%.

[0233] Comparing the experimental results of Comparative Example 6 and Example 1, it can be seen that the purity and yield of iminostilbene obtained in Comparative Example 5 are low, and the reaction process is sticky. This is because the temperature is too high, a large number of byproducts are generated in this step, which cause stickiness during the reaction and are difficult to purify.

[0234] The purity and yield data of some compounds involved in the above examples and comparative examples are shown in Table 3.

[0235] Table 3: Purity and Yield of Some Compounds Involved in the Examples and Comparative Examples

[0236]

[0237] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0238] For those skilled in the art, various modifications and improvements can be made without departing from the concept of the present invention, and these modifications and improvements are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A compound based on an imino structure, characterized in that, The compound has the following chemical structural formula: ； Where n = 2~4, R1 is any one of hydrogen or alkoxy; R2 is any one of hydrogen or alkoxy.

2. The compound based on the imino structure according to claim 1, characterized in that, The alkoxy group is -OCH3.

3. The compound based on the imino structure according to claim 1, characterized in that, The compound is selected from any of the following chemical structures: 。 4. A method for preparing a compound based on an imino structure according to any one of claims 1-3, characterized in that, The preparation method includes the following steps: S1. Under the action of sodium hydride, compound 1, which has the following structural formula, reacts with diethyl bromoalkyl phosphate to generate diethyl alkylphosphonate based on the imino structure. S2. Under inert gas conditions, the alkylphosphonate diethyl ester with an imino structure obtained in step S1 reacts with trimethylbromosilane and methanol to generate the target product, a compound with an imino structure. In step S1, the alkyl group in the brominated alkyl phosphate diethyl ester is any one of C2 to C4; The structural formula of compound 1 based on imino groups is: ; Wherein, R1 is any one of hydrogen or alkoxy; R2 is any one of hydrogen or alkoxy.

5. The method for preparing the compound based on the imino structure according to claim 4, characterized in that, In step S1, the molar ratio of the imino-based compound 1, the diethyl brominated alkyl phosphate, and the sodium hydride is 1:(1~5):(1~2.5). In step S2, the molar ratio of the alkylphosphonate diethyl ester based on the imino structure and the trimethylbromosilane is 1:(1~10). In step S2, the mass ratio of the alkylphosphonate diethyl ester based on the imino structure to the methanol is 1:(5~10).

6. The method for preparing the compound based on the imino structure according to claim 4, characterized in that, In step S1, the reaction temperature is 20~50℃ and the reaction time is 2~10 hours; In step S2, the reaction temperature is 40~80℃ and the reaction time is 2~10 hours; In step S1, the solvent is at least one of tetrahydrofuran, dimethyl sulfoxide, and dioxane; In step S2, the solvent is at least one of dichloromethane, dichloroethane, toluene, dioxane, and methanol.

7. An application of a compound based on an imino structure according to any one of claims 1-3, characterized in that, The compound is used in perovskite solar cell devices.

Images