A self-crosslinking compound, a preparation method and application thereof

Abstract

The application belongs to the technical field of solar cells, and particularly relates to a self-crosslinking compound and a preparation method and application thereof. The preparation method comprises the following steps: tri(4-hydroxyphenyl)amine, p-chloromethylstyrene, a halogenated reagent and an inorganic base are added into a solvent, and reflux reaction is carried out under an inert atmosphere for 12-24 hours; and the reaction solution is treated to obtain the self-crosslinking compound. The self-crosslinking compound prepared by the application has multiple crosslinking sites, and the crosslinking reaction can be completed in a perovskite annealing process, a polymer network formed by the crosslinking reaction can effectively prevent moisture penetration and reduce ion migration, so that a high-efficiency and stable perovskite solar cell device is prepared. The perovskite device prepared by using the self-crosslinking material of the application achieves a photoelectric conversion efficiency of 24.53%, an open-circuit voltage of 1.21V, a short-circuit current of 25.50 mA cm ‑2 , and a fill factor of 79.19%, and the stability of the device is greatly improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solar cells, and particularly relates to a self-crosslinking compound and a preparation method and application thereof. BACKGROUND

[0002] Solar cells can be divided into three generations according to their development stages and principles, and each generation represents a series of technical progress and innovation. The first generation of solar cells is mainly silicon-based materials: single crystal silicon cells have relatively high conversion efficiency, but the cost is relatively high; polycrystalline silicon is cheaper than single crystal silicon, but the efficiency is slightly lower. The second generation of solar cells uses multi-element compound thin film technology (uses materials such as gallium arsenide (GaAs), copper indium gallium selenide (CIGS), cadmium telluride (CdTe), etc.), although the efficiency is high, but the materials used by the cell are relatively scarce, which limits the further development of the cell. The third generation of solar cells includes perovskite solar cells (PSCs), dye-sensitized solar cells (DSSC), organic solar cells (OPV), quantum dot solar cells (QDSCs), etc. Among them, perovskite solar cells are considered as one of the important technical directions to replace traditional silicon-based solar cells, and are highly regarded due to their unique material properties, such as high efficiency, low cost, adjustable energy band gap, and lightweight flexibility. Since the advent of perovskite solar cells, although certain progress has been made, there is still room for improvement in terms of efficiency, stability, service life, and sustainability, especially in terms of stability under complex and variable environmental conditions.

[0003] Perovskite thin films prepared by solution method have a large number of defects such as grain boundaries, dislocations, vacancies and redox defects, which will reduce the charge transport efficiency of the thin film, shorten the carrier lifetime, and cause the stability of the device to decrease. Additive engineering is a means to effectively overcome various defects in the process of preparing perovskite thin films by solution method. Small molecule and polymer additives are two commonly used additive types. Small molecule additives are small in volume, easy to diffuse into the interior of perovskite thin film and combine with defect sites, and have a wide variety, which can be selectively regulated according to different defect types, and are relatively cheap and easy to mass produce; however, the binding force of small molecule additives with perovskite thin film is weak, and they are easy to fall off and may decompose at high temperature, affecting the stability of the thin film. The binding force of polymer additives with perovskite thin film is strong, which improves the stability of perovskite thin film; however, the solubility of polymer is poor, the utilization efficiency is low, the diffusivity is poor, it is difficult to enter the interior of the thin film, and the conductivity is poor, which affects the device efficiency, and the price is relatively high, the production cost is high.

[0004] So far, most of the reported in-situ crosslinking molecules are insulators, and perovskite solar cells with insulating polymers may damage the transfer of carriers and reduce photovoltaic performance. And due to the single reaction site of the in-situ polymerization molecule, the low linear crosslinked skeleton formed after polymerization is brittle and loose. Therefore, there is an urgent need for a compound that combines the advantages of small molecules and polymer additives, which has multiple passivation sites, low cost and good solubility, molecular regulation, and post-polymerization thermal stability. SUMMARY

[0005] In order to overcome the shortcomings of the prior art, one of the purposes of the present application is to provide a self-crosslinking compound which has multiple passivation sites, low cost and good solubility, molecular regulation, and post-polymerization thermal stability.

[0006] One of the purposes of the present application is achieved by adopting the following technical solutions:

[0007] A self-crosslinking compound, the structure of the self-crosslinking compound is as follows:

[0008]

[0009] The second purpose of the present application is to provide a preparation method of a self-crosslinking compound.

[0010] The second purpose of the present application is achieved by adopting the following technical solutions:

[0011] The preparation method of the self-crosslinking compound comprises the following steps: tri(4-hydroxyphenyl)amine, p-chloromethylstyrene, halogenating reagent, inorganic base are added to the solvent, refluxed under inert atmosphere for 12-24h, and the reaction solution is treated to obtain the self-crosslinking compound.

[0012] Further, the molar amount ratio of the tri(4-hydroxyphenyl)amine, p-chloromethylstyrene, halogenating reagent, inorganic base is 1:(3.0-3.5):(0.3-0.4):(5.8-6.5).

[0013] Further, the halogenating reagent is one of tetrabutylammonium bromide and tetrabutylammonium iodide; the inorganic base is one of potassium hydroxide and sodium tert-butoxide; and the solvent is toluene.

[0014] Further, the preparation method of the tri(4-hydroxyphenyl)amine comprises the following steps: tri(4-methoxyphenyl)amine, boron tribromide are added to dichloromethane under low temperature conditions, and the reaction is carried out at room temperature for 11-15h under inert atmosphere, and the reaction solution is treated to obtain tri(4-hydroxyphenyl)amine.

[0015] Further, the molar amount ratio of the tri(4-methoxyphenyl)amine, boron tribromide is 1:(3.3-3.6).

[0016] Further, the preparation method of the tris(4-methoxyphenyl)amine comprises the following steps: adding iodobenzene methyl ether, bis(4-methoxyphenyl)amine, potassium tert-butoxide, tri-tert-butylphosphonium tetrafluoroborate and tris(dibenzylideneacetone)dipalladium into toluene, and reacting at 90-110 DEG C for 12-16 hours under an inert atmosphere; and the tris(4-methoxyphenyl)amine is obtained by treating the reaction solution.

[0017] Further, the molar ratio of bis(4-methoxyphenyl)amine, iodobenzene methyl ether, potassium tert-butoxide, tri-tert-butylphosphonium tetrafluoroborate and tris(dibenzylideneacetone)dipalladium is 1:(1.1-1.5):(3.0-3.5):(0.1-0.3):(0.3-0.6).

[0018] The third object of the present application is to provide an application of the self-crosslinking compound.

[0019] The third object of the present application is achieved by the following technical solution:

[0020] The self-crosslinking compound is used to prepare a perovskite film or a perovskite solar cell.

[0021] The fourth object of the present application is to provide a perovskite solar cell.

[0022] The fourth object of the present application is achieved by the following technical solution:

[0023] The perovskite solar cell comprises a transparent conductive oxide layer, an electron transport layer, a perovskite layer, a hole transport layer and an electrode, wherein the perovskite layer is prepared from a perovskite precursor solution to which the self-crosslinking compound is added.

[0024] Further, the concentration of the self-crosslinking compound in the perovskite precursor solution is 0.5 g / L.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] The self-crosslinking compound prepared by the present application has multiple crosslinking sites, and the crosslinking reaction can be completed during the perovskite annealing process, and the polymer network formed can effectively prevent moisture penetration and reduce ion migration, so that a high-efficiency and stable perovskite solar cell device is prepared. -2 The perovskite device prepared by using the self-crosslinking material of the present application achieves a photoelectric conversion efficiency of 24.53%, an open-circuit voltage of 1.21 V, a short-circuit current of 25.50 mA cm BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The synthesis of the self-crosslinking compound of the present application is shown in the following schematic diagram:

[0028] Figure 2 1H NMR spectrum of tris(4-methoxyphenyl)amine prepared in this invention 1 H NMR spectrum;

[0029] Figure 3 Carbon NMR spectrum of tris(4-methoxyphenyl)amine prepared in this invention 13 C NMR spectrum;

[0030] Figure 4 1H NMR spectrum of tris(4-hydroxyphenyl)amine prepared in this invention 1 H NMR spectrum;

[0031] Figure 5 Carbon NMR spectrum of tris(4-hydroxyphenyl)amine prepared in this invention 13 C NMR spectrum;

[0032] Figure 6 The 1H NMR spectrum of the self-crosslinking compound prepared in this invention 1 H NMR spectrum;

[0033] Figure 7 Carbon NMR spectrum of the self-crosslinking compound prepared in this invention 13 C NMR spectrum;

[0034] Figure 8 This is a schematic diagram of the structure of the perovskite solar cell prepared in Example 4 of the present invention;

[0035] Figure 9 This is a schematic diagram of the electrostatic potential distribution and frontier molecular orbital results of the self-crosslinking compound prepared in this invention;

[0036] Figure 10 This is a schematic diagram of the differential scanning calorimetry results of the self-crosslinking compound prepared in this invention.

[0037] Figure 11 The Fourier transform infrared (FTIR) spectra of the self-crosslinking compound prepared in this invention before and after crosslinking are shown.

[0038] Figure 12 This is a schematic diagram of the transmission electron microscope (TEM) results of the perovskite device FTO / TPA-VB / Au prepared in Example 4 of the present invention;

[0039] Figure 13 The current density-voltage (JV) characteristic curve of the perovskite solar cell prepared in Example 4 of the present invention is shown.

[0040] Figure 14 This is the electrochemical impedance spectroscopy (EIS) spectrum of the perovskite solar cell prepared in Example 4 of the present invention. Detailed Implementation

[0041] The present invention will now be further described with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, all reagents or instruments used are conventional products obtained through commercial channels.

[0042] Example 1

[0043] A method for preparing a self-crosslinking compound, such as Figure 1 As shown, it includes the following steps:

[0044] (1) In a dry 100 mL Schrank flask, p-iodoanisole (2.8 g, 11.9 mmol), bis(4-methoxyphenyl)amine (2.5 g, 10.9 mmol), potassium tert-butoxide (t-BuOK, 3.67 g, 32.7 mmol), tritert-butylphosphine tetrafluoroborate (0.32 g, 1.09 mmol) and tridibenzylacetone dipalladium (Pd2(dba)3, 0.3 g, 0.327 mmol) were dissolved in 30 mL of toluene. The reaction was heated to 90 °C under an argon atmosphere and reacted for 12 hours. After the reaction was completed, 20 mL of ice water was added to the reaction mixture to quench it, and the reaction solution was extracted with dichloromethane. The combined organic phases were dried with anhydrous sodium sulfate and purified by column chromatography (eluent: ethyl acetate to petroleum ether, volume ratio 1:14). After purification and concentration, 3.0 g of tri(4-methoxyphenyl)amine (yield 83%) was obtained.

[0045] Tris(4-methoxyphenyl)amine 1 The H NMR results are as follows Figure 2 As shown, 1 H NMR (400MHz, DMSO-d6) δ6.86–6.76(m,12H),3.70–3.62(m,9H).

[0046] Tris(4-methoxyphenyl)amine 13 The C NMR results are as follows Figure 3 As shown, 13 C NMR (101MHz, DMSO-d6) δ155.14, 141.90, 124.98, 115.26, 55.73.

[0047] MS of tris(4-methoxyphenyl)amine: m / z (%) [M + calcd for C 21 H 21NO3: 335.152; found: 336.155.

[0048] (2) In a 100 ml dry round bottom flask, tris(4-methoxyphenyl)amine (1.5 g, 4.45 mmol) was added and dissolved in 20 ml dichloromethane, after complete dissolution, 15 ml of boron tribromide (1 M solution in dichloromethane) was slowly added, after stirring the reaction for 1 hour, the reaction was warmed to room temperature and stirred for 11 hours; to the reaction was added 10 ml of deionized water and stirred for 1 hour, after which the reaction was extracted with ethyl acetate, the combined organic layers were dried over anhydrous sodium sulfate and purified by column chromatography (eluent, volume ratio of ethyl acetate to petroleum ether 1 :2), after purification, concentration, 1.3 g of tris(4-hydroxyphenyl)amine was obtained (yield 97%).

[0049] MS of tris(4-hydroxyphenyl)amine: m / z (%) [M+] calcd for C 1 H NMR results are shown in Table 1. Figure 4 1 H NMR (400 MHz, DMSO-d6) δ 9.05 (s, 3H), 6.68 (dt, J = 8.0, 4.0 Hz, 6H), 6.59 (dt, J = 8.0, 4.0 Hz, 6H).

[0050] MS of tris(4-hydroxyphenyl)amine: m / z (%) [M+] calcd for C 13 C NMR results are shown in Table 2. Figure 5 13 C NMR (101 MHz, DMSO-d6) δ 152.94, 140.92, 124.97, 116.37.

[0051] MS of tris(4-hydroxyphenyl)amine: m / z (%) [M+] calcd for C 18 H 15 NO3: 293.105; found: 294.109.

[0052] (3) In a 150 ml dry round bottom flask, tris(4-hydroxyphenyl)amine (1 g, 3.4 mmol), p-chloromethylstyrene (1.6 g, 10.5 mmol), tetrabutylammonium bromide (0.34 g, 1.05 mmol) were dissolved in 30 ml of toluene. Then 10 ml of 2M aqueous potassium hydroxide solution was slowly added and stirred at room temperature for 12 hours; the reaction was quenched by adding 20 ml of ice water to the reaction and the reaction was extracted with ethyl acetate, the combined organic layers were dried over anhydrous sodium sulfate and purified by column chromatography (eluent, volume ratio of ethyl acetate to petroleum ether 1 :20), after concentration, 1.8 g of self-crosslinking compound was obtained (yield 82%).

[0053] MS of self-crosslinking compound: m / z (%) [M+] calcd for C 1 ​​H NMR results are shown in Table 1. Figure 6 1 H NMR (400 MHz, DMSO-d6) δ 7.49 - 7.43 (m, 6H), 7.37 (d, J = 8.2 Hz, 6H), 6.89 (dt, J = 12.0, 4.0 Hz, 6H), 6.83 (dt, J = 12.0, 4.0 Hz, 6H), 6.71 (dd, J = 16.0, 12.0 Hz, 3H), 5.81 (dd, J = 16.0, 1.2 Hz, 3H), 5.23 (dd, J = 8.0, 4.0 Hz, 3H), 4.99 (s, 6H).

[0054] MS of the self-crosslinking compound: 13 C NMR results are shown in Table 1. Figure 7 13 C NMR (101 MHz, DMSO-d6) δ 154.26, 141.98, 137.41, 137.18, 136.83, 128.48, 126.72, 124.98, 116.18, 114.98, 69.69.

[0055] MS of the self-crosslinking compound: m / z (%) [M + ] calcd for C45H39NO3: 641.293; found: 642.294.

[0056] The self-crosslinking compound obtained by the above preparation method is also provided.

[0057] Example 2

[0058] The synthesis of a self-crosslinking compound includes the following steps:

[0059] (1) Dissolve p-iodoanisole (13 mmol), bis(4-methoxyphenyl)amine (10.9-12 mmol), potassium tert-butoxide (35 mmol), tri-tert-butylphosphonium tetrafluoroborate (2.35 mmol) and tris(dibenzylideneacetone)dipalladium (0.47 mmol) in 30 mL of toluene in a dry 100 mL Schlenk flask, heat the reaction to 90°C under argon atmosphere, and react for 14 hours; after the reaction is completed, quench the reaction mixture by adding 20 mL of ice water, extract the reaction solution with dichloromethane, dry the combined organic phase with anhydrous sodium sulfate, and purify by column chromatography (eluent, volume ratio of ethyl acetate to petroleum ether is 1:14) to obtain tris(4-methoxyphenyl)amine after concentration. 1 H NMR, 13 C NMR and MS show results consistent with those of Example 1.

[0060] ​​(2) At -84℃, tris(4-methoxyphenyl)amine (4.45 mmol) was added to a 100 mL dry round-bottom flask and dissolved in 20 mL dichloromethane. After complete dissolution, 15 mL boron tribromide (1 M dichloromethane solution) was slowly added. After stirring for 1 hour, the reaction was heated to room temperature and stirred for 13 hours. 10 mL deionized water was added to the reaction solution and stirred for 1 hour. The reaction solution was extracted with ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and then purified by column chromatography (eluent: ethyl acetate to petroleum ether in a volume ratio of 1:2). The purified and concentrated solution was tris(4-hydroxyphenyl)amine. 1 H NMR, 13 The results shown by CNMR and MS are consistent with those of Example 1.

[0061] (3) In a 150 mL dry round-bottom flask, tris(4-hydroxyphenyl)amine (3.4 mmol), p-chloromethylstyrene (13.6 mmol), and tetrabutylammonium bromide (1.36 mmol) were dissolved in 30 mL toluene. Then, 11 mL of 2 M potassium hydroxide aqueous solution was slowly added, and the reaction was stirred at room temperature for 12–18 hours. The reaction was quenched with 20 mL of ice water, and the reaction solution was extracted with ethyl acetate. The combined organic layers were dried with anhydrous sodium sulfate and separated by column chromatography (eluent: ethyl acetate to petroleum ether, volume ratio 1:20). After concentration, the self-crosslinking compound was obtained. 1 H NMR, 13 The results shown by C NMR and MS were consistent with those of Example 1.

[0062] This embodiment also provides a self-crosslinking compound obtained by the above preparation method.

[0063] Example 3

[0064] The synthesis of a self-crosslinking compound includes the following steps:

[0065] (1) In a dry 100 mL Schrank flask, p-iodoanisole (16 mmol), bis(4-methoxyphenyl)amine (10.9 mmol), potassium tert-butoxide (38 mmol), tri-tert-butylphosphine tetrafluoroborate (3.27 mmol) and tridibenzylacetone dipalladium (0.654 mmol) were dissolved in 30 mL of toluene. The reaction was heated to 90 °C under an argon atmosphere and reacted for 16 hours. After the reaction was completed, 20 mL of ice water was added to the reaction mixture to quench it, and the reaction solution was extracted with dichloromethane. The combined organic phases were dried with anhydrous sodium sulfate and purified by column chromatography (eluent: ethyl acetate to petroleum ether in a volume ratio of 1:14). After purification and concentration, tri(4-methoxyphenyl)amine was obtained. 1 H NMR, 13The results shown by C NMR and MS are consistent with those of Example 1.

[0066] (2) At -84℃, tris(4-methoxyphenyl)amine (4.45 mmol) was added to a 100 mL dry round-bottom flask and dissolved in 20 mL dichloromethane, after complete dissolution, 16 mL boron tribromide (1M dichloromethane solution) was slowly added, after stirring for 1 hour, the reaction was warmed to room temperature and stirred for 15 hours; 10 mL deionized water was added to the reaction solution and stirred for 1 hour, then the reaction solution was extracted with ethyl acetate, the combined organic phase was dried over anhydrous sodium sulfate and then separated by column chromatography (eluent, volume ratio of ethyl acetate to petroleum ether 1:2) to obtain tris(4-hydroxyphenyl)amine after purification, concentration and drying. 1 H NMR, 13 The results shown by C NMR and MS are consistent with those of Example 1.

[0067] (3) In a 150 mL dry round-bottom flask, tris(4-hydroxyphenyl)amine (3.4 mmol), p-chloromethylstyrene (12 mmol), and tetrabutylammonium iodide (1.2 mmol) were dissolved in 30 mL toluene. Then 10 mL 2M aqueous potassium hydroxide solution was slowly added and stirred at room temperature for 24 hours; the reaction was quenched by adding 20 mL ice water and the reaction solution was extracted with ethyl acetate, the combined organic layer was dried over anhydrous sodium sulfate and separated by column chromatography (eluent, volume ratio of ethyl acetate to petroleum ether 1:20), concentrated to obtain the self-crosslinking compound. 1 H NMR, 13 The results shown by C NMR and MS are consistent with those of Example 1.

[0068] The self-crosslinking compound obtained by the preparation method described above is also provided in the embodiment.

[0069] Example 4

[0070] A perovskite solar cell, as shown in the structure Figure 8 from bottom to top, includes a transparent conductive oxide layer, an electron transport layer, a perovskite layer, a hole transport layer, and an electrode. The perovskite layer is prepared from a perovskite precursor solution to which the self-crosslinking compound prepared in Example 1 is added. The amount of the self-crosslinking compound added to the perovskite precursor solution is 0.5 g / mL.

[0071] The perovskite precursor solution described in the present application uses a mixed solvent of DMF:DMSO=8:1, and the perovskite precursor solution described in the present application can use a precursor solution well known to those skilled in the art, without special requirements.

[0072] Comparative Example 1

[0073] A perovskite solar cell, which is different from that of Example 4 in that the self-crosslinking compound prepared in Example 1 is not added in the perovskite layer.

[0074] Test Example 1

[0075] The electrostatic potential distribution and the results of the calculation of the frontier molecular orbitals of the self-crosslinking compound prepared in Example 1 are shown in Figure 9 From the structure, the self-crosslinking compound prepared in the application has a triphenylamine core, an interaction group and a crosslinking group. The triphenylamine core can adjust the energy level to make the energy level of the perovskite more matched with the energy level of the hole transport layer; the interaction group of the molecule is an ether group, and the lone pair of electrons of the ether bond can interact with the perovskite; the ethylene group can complete crosslinking during the annealing process of the perovskite; therefore, the molecule prepared in the application has multiple crosslinking sites and has a higher crosslinking degree in the spatial dimension, which can form a polymer network to wrap the perovskite film, thereby passivating the defects of the perovskite and protecting the perovskite.

[0076] From the electrostatic potential distribution of the molecule Figure 9 , it can be seen that the electrons at the oxygen atom are relatively dense, which can more easily interact with the uncoordinated Pb 2+ in the perovskite. In addition, the results of the calculation of the frontier molecular orbitals show that the highest occupied molecular orbital (HOMO) of two crosslinking molecules is mainly distributed near the triphenylamine core, and the lowest unoccupied molecular orbital is mainly distributed near the styrene, which will form a strong intramolecular charge transfer inside the molecule, which is beneficial to the hole transport of the molecule, and the energy level of the material is more matched with the perovskite and Spiro-OMeTAD, which is more conducive to the transport of holes and reduces the loss of charges at the interface.

[0077] Test Example 2

[0078] The self-crosslinking compound prepared in Example 1 was subjected to thermodynamic testing using a differential scanning calorimeter, as shown in Figure 10 . The sample box used for testing was an aluminum crucible, the reference sample was a different aluminum crucible of the same batch, the heating rate was 10℃ / min, and the cooling rate was 20℃ / min.

[0079] From the thermodynamic testing Figure 10 , it can be seen that the melting point of the material is 71℃, and the crosslinking temperature is 110℃, indicating that the self-crosslinking compound prepared in the application can be self-crosslinked at 110℃.

[0080] Test Example 3

[0081] Fourier transform infrared spectroscopy (FTIR) was used to test the self-crosslinking compound prepared in Example 1 before and after heating. One self-crosslinking compound prepared in Example 1 was dissolved in ethyl acetate and spin-coated onto a glass slide at 3000 rpm for FTIR testing. Another self-crosslinking compound prepared in Example 1 was dissolved in ethyl acetate, spin-coated onto a glass slide at 3000 rpm, and heated at 100°C for 1 hour on a hot stage for FTIR testing. The results are as follows: Figure 11 As shown.

[0082] Depend on Figure 11 It can be seen that the self-crosslinking compound after heating is located at 1608 cm⁻¹. -1 The disappearance of the stretching vibration peak at C=C indicates that the self-crosslinking compound prepared in this invention is fully crosslinked after annealing.

[0083] Test Example 4

[0084] To verify that the self-crosslinking compound prepared in this invention forms a polymer during the fabrication of perovskite devices, this experimental example was characterized by transmission electron microscopy (TEM). The sample preparation process was as follows: the self-crosslinking compound was dissolved in a perovskite precursor solution at a concentration of 0.5 g / mL. The perovskite was then spin-coated onto an FTO surface and annealed at 100°C for 1 hour. The perovskite powder sample was scraped off the FTO surface and dispersed in n-octane solvent, sonicated for 10 seconds, and then 15 μL of solvent was pipetted onto a copper grid. Finally, excess solvent was dried under vacuum to obtain the TEM-characterized sample. The TEM image is shown below. Figure 12 As shown.

[0085] Depend on Figure 12 It can be seen that the perovskite grains with clear lattice fringes in the characterization sample show an amorphous polymer phase at the edge of these grains, proving that the self-crosslinking small molecule compound of the present invention forms a polymer during the fabrication of perovskite devices.

[0086] Experimental Example 5

[0087] In the AM 1.5G standard solar simulator, the simulated solar irradiance is 100 mW / cm². -2 Under the specified conditions, the current density-voltage (JV) characteristic curves of the perovskite solar cells prepared in Example 4 and Comparative Example 1 were tested, as follows: Figure 13 As shown.

[0088] Depend on Figure 13 It can be seen that the photoelectric conversion efficiency and open-circuit voltage V of the perovskite solar cells in Comparative Example 1 and Example 4 are... OC The short-circuit current Jsc and fill factor FF are 22.38%, 1.16V, and 25.13mA, respectively. -2 76.34% and 24.53%, 1.21V, 25.50mAcm-2 79.19%.

[0089] Test Example 6

[0090] The perovskite solar cells of Example 4 and Comparative Example 1 were characterized by electrochemical impedance spectroscopy (EIS), as shown in Figure 14

[0091] As can be seen from Figure 14 , the transfer resistance Rct of the device of Comparative Example 1 was 97.40 Ω, and the transfer resistance Rct of the device of Example 4 dropped to 52.34 Ω; the recombination resistance Rrec of the device of Comparative Example 1 was 518.86 KΩ, and the recombination resistance Rrec of the device of Example 4 was improved to 1004.7 KΩ.

[0092] The above embodiments are only preferred embodiments of the present application, and cannot be used to limit the scope of protection of the present application. Any non-essential changes and substitutions made by those skilled in the art on the basis of the present application are within the scope of the present application.​

Claims

1. A method for preparing a self-crosslinking compound, characterized by, The method comprises the following steps: The tris(4-hydroxyphenyl)amine, p-chloromethylstyrene, halogenated reagent, inorganic base are added into a solvent, and the reaction is carried out under reflux for 12-24 h in an inert atmosphere, and the reaction solution is treated to obtain a self-crosslinking compound; the structural formula of the self-crosslinking compound is 。 2. The method for preparing the self-crosslinking compound according to claim 1, characterized in that, The molar ratio of the tris(4-hydroxyphenyl)amine, p-chloromethylstyrene, halogenated reagent, inorganic base is 1:(3.0-3.5):(0.3-0.4):(5.8-6.5).

3. The method for preparing the self-crosslinking compound according to claim 1, characterized in that, The halogenated reagent is one of tetrabutylammonium bromide and tetrabutylammonium iodide; the inorganic base is one of potassium hydroxide and sodium hydroxide; and the solvent is toluene.

4. The method for preparing the self-crosslinking compound according to claim 1, characterized in that, The preparation method of the tris(4-hydroxyphenyl)amine comprises the following steps: tris(4-methoxyphenyl)amine and boron tribromide are added into dichloromethane at-84 °C, and the reaction is carried out at room temperature for 11-15 h in an inert atmosphere, and the reaction solution is treated to obtain the tris(4-hydroxyphenyl)amine.

5. The method for preparing the self-crosslinking compound according to claim 1, characterized in that, The molar ratio of the tris(4-methoxyphenyl)amine and boron tribromide is 1:(3.3-3.6).

6. The method for preparing the self-crosslinking compound according to claim 1, characterized in that, The preparation method of the tris(4-methoxyphenyl)amine comprises the following steps: p-iodoanisole, bis(4-methoxyphenyl)amine, potassium tert-butoxide, tri-tert-butylphosphonium tetrafluoroborate, and tris(dibenzylideneacetone)dipalladium are added into toluene, and the reaction is carried out at 90-110 °C for 12-16 h in an inert atmosphere, and the reaction solution is treated to obtain the tris(4-methoxyphenyl)amine.

7. The method for preparing the self-crosslinking compound according to claim 6, characterized in that, The molar ratio of the bis(4-methoxyphenyl)amine, p-iodoanisole, potassium tert-butoxide, tri-tert-butylphosphonium tetrafluoroborate, and tris(dibenzylideneacetone)dipalladium is 1:(1.1-1.5):(3.0-3.5):(0.1-0.3):(0.3-0.6).

Images