Synthesis method of novel electron transport layer material and application of novel electron transport layer material in perovskite solar cell

Abstract

The invention belongs to the technical field of perovskite solar cells, and relates to a synthesis method of a novel electron transport layer material and an application of the novel electron transport layer material in a perovskite solar cell, (2-aminoethyl) diethyl phosphonate, 1, 8-naphthalic anhydride and 4-dimethylaminopyridine are mixed, reacted, filtered and purified, and then react with trimethylbromosilane to obtain the novel electron transport layer material. The novel electron transport layer material YG25 is an organic phosphonic acid small molecule with a naphthalimide structure; when the organic self-assembled perovskite thin film is applied to a perovskite device as an electron transport layer, dynamic self-assembly of organic molecules in the thin film is realized, passivation is performed on a perovskite interface, the microstructure of the upper surface of the perovskite layer is improved, and the organic self-assembled small molecules also generate chemical bonding action with an ITO layer on the upper interface of the electron transport layer, so that the perovskite device is more stable in performance. Diffusion of the electrode into the device is slowed down; the YG25 preparation method is simple, easy to operate, low in cost, capable of being applied to perovskite solar cells and wide in market prospect.

Description

Technical field:

[0001] The invention belongs to the technical field of perovskite solar cells and relates to a novel phosphonic acid self-assembly molecule as an electron transport layer and an application thereof in a formal perovskite solar cell. Background technology:

[0002] The advantages of perovskite solar cells are their adjustable band gap, high absorption coefficient, long carrier diffusion length and low manufacturing cost. These characteristics make perovskite cells have broad application prospects in flexible electronics, building integrated photovoltaics and portable energy devices. The development history of perovskite solar cells is relatively short, but it has made rapid progress. In 2009, Japanese scientists used perovskite materials to prepare solar cells for the first time, and their initial efficiency was only 3.8%. However, with the development of materials science and nanotechnology, the efficiency of perovskite solar cells has increased significantly in just a few years. As of 2024, laboratory-scale perovskite cells have been able to achieve a photoelectric conversion efficiency of more than 26%, comparable to the mainstream silicon-based solar cells on the market. However, the stability and long-term durability of perovskite materials remain the focus of current research, as these factors directly affect the commercial application of batteries.

[0003] Researchers are exploring different material formulations, device structures, and packaging technologies to improve the stability and lifespan of perovskite solar cells. At the same time, environmental impact and material sustainability are also important research directions, because perovskite materials may contain heavy metals such as lead, and more environmentally friendly alternative materials need to be found. Overall, as an emerging technology, perovskite solar cells are developing rapidly and are expected to play an important role in the future energy sector. With the continuous advancement of technology and the overcoming of challenges, perovskite solar cells are expected to achieve large-scale commercial production and contribute to global sustainable energy solutions.

[0004] Typically, high-efficiency nip-type perovskite solar cells use SnO 2 As an electron transport layer. Tin oxide has excellent properties such as high electron mobility, wide band gap, good energy level matching with the perovskite light absorption layer and good chemical stability, and has gradually become the most promising electron transport layer material. Despite the above advantages, SnO 2 Oxygen vacancies, hanging hydroxyl groups, and uncoordinated metal atoms inside and on the surface of the film make the efficiency of electron extraction and transport low, leading to interface carrier accumulation and non-radiative recombination. In addition to the electron transport layer, the quality of the perovskite film is also very important for obtaining high-efficiency, long-term stable devices. Poor crystallization quality of perovskite will lead to increased defect density inside the film and at the interface, becoming the center of non-radiative recombination. In addition, SnO 2The buried interface of SnO / perovskite will significantly affect the crystallization quality of the upper perovskite film. Therefore, it is of great significance to adjust the perovskite crystallization by modifying and optimizing the electron transport layer. 2 Guo et al. modified SnO by introducing formamide oxalate 2 / perovskite buried interface, reducing defects at the interface and regulating carrier dynamics to improve device performance. In addition, some additives are used to modify SnO 2 Electron transport layers, such as phosphoethanolamine (PE), polyethylene glycol diacrylate (PEGDA), potassium heparin (HP), etc. However, the defect-related carrier recombination at the interface between the electron transport layer and the perovskite leads to a large open circuit voltage loss. And due to the non-exposed characteristics of the buried interface, it is still challenging to understand and optimize the buried interface. Summary of the invention:

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a new electron transport layer material and a preparation method thereof in a formal perovskite solar cell, by replacing the traditional SnO 2 The interface between the indium tin oxide layer and the perovskite layer is modified by using a new organic phosphonic acid small molecule material YG25 as an electron transport layer to further optimize the performance of the perovskite battery.

[0006] In order to solve the above technical problems, the present invention provides a method for preparing a novel electron transport layer material YG25, comprising the following steps:

[0007] (1) Add diethyl (2-aminoethyl)phosphonate (5.5 mmol), 1,8-naphthalic anhydride (1 g, 5 mmol) and 4-dimethylaminopyridine (DMAP) (0.672 g, 5.5 mmol) into a three-necked flask, and react at 50-90° C. for 12-36 h; then dilute the reaction mixture with water, and cool the mixture to 0° C.; collect the resulting solid by vacuum filtration; wash the solid with water to obtain a crude product; the crude product is purified by column chromatography (DCM:PE=1:5, v / v) to obtain 1.5 g of a white solid as compound 3;

[0008]

[0009] (2) Compound 3 (0.9 g, 2.5 mmol) was dissolved in anhydrous 1,4-dioxane (20 mL) under a nitrogen atmosphere, and trimethylsilyl bromide (5.3 mL, 40 mmol) was added. The reaction was stirred at room temperature under a nitrogen atmosphere for 10-30 h. Then, methanol (10 mL) was added and the stirring was continued for 1-5 h. Finally, an excess of distilled water was added until the solution became opaque and stirred overnight. The solution was filtered and the obtained solid was washed with water and dichloromethane. After filtering again, the obtained solid was washed with n-hexane to obtain 0.710 g of a white powder, which was the electron transport layer material YG25. YG25 is an organic small molecule with a phosphonic acid group.

[0010]

[0011] The present invention also provides a method for preparing a perovskite solar cell, comprising the following steps:

[0012] (1) dissolving an organic molecule having a phosphonic acid group in DMSO to obtain a precursor solution;

[0013] (2) spin coating the precursor solution on an ITO substrate at room temperature to form a monolayer, and then placing it on a hot stage for annealing to obtain an electron transport layer;

[0014] Furthermore, in step (1), the concentration of the precursor solution is 10 mg / mL; in step (2), the film thickness of the monolayer is 5 nm to 20 nm;

[0015] Furthermore, in step (2), the annealing temperature is 110° C. and the annealing time is 5 min to 10 min;

[0016] Furthermore, in step (2), the spin coating speed is 2000 rpm to 6000 rpm, and the spin coating time is 20 s to 60 s; before the spin coating begins, the precursor solution is attached to the ITO surface and allowed to stand in contact for 10 s to 30 s;

[0017] (3) Spin-coating the perovskite solution and the Spiro-OMeTAD solution on the prepared electron transport layer in sequence; then, transferring the device to the evaporation station, and evaporating MoO 3 and silver electrodes.

[0018] The present invention also provides a perovskite solar cell, comprising ITO, an electron transport layer, a perovskite layer, a hole transport layer, and MoO 3 , silver electrode.

[0019] Furthermore, the electron transport layer is a film layer prepared from a DMSO solution of an organic small molecule with a phosphonic acid group, and the solution concentration is 10 mg / mL.

[0020] Furthermore, the perovskite layer is a film layer prepared by dissolving lead iodide, lead acetate, methylamine iodide and methylamine bromide in N,N-dimethylformamide in a material ratio of 0.4:0.6:2.05:0.15, and the solution concentration is 2 mol / mL.

[0021] Furthermore, the electron transport layer is a film layer prepared by a solution obtained by dissolving YG25, and the concentration of the solution is 10 mg / mL.

[0022] The present application selects organic molecules to be dissolved in a DMSO solution, and after high-temperature annealing, a thin film is formed on the indium tin oxide (ITO) layer, which effectively improves the flatness of the interface between the indium tin oxide and the perovskite, and also has a certain effect on the grain size, making the film smoother and denser, so that the indium tin oxide layer and the perovskite layer can be more matched, thereby improving the performance of the solar cell, especially the improvement of the open circuit voltage is more obvious.

[0023] The present invention provides a novel naphthalene imine structured organic phosphonic acid small molecule YG25, which is dissolved in a DMSO solution to achieve passivation at the perovskite interface. The results show that compared with the traditional perovskite solar cell using SnO 2 As an electron transport layer, YG25 effectively avoids oxygen vacancies, hanging hydroxyl groups and uncoordinated metal atoms inside and on the surface of the film. At the same time, the carbonyl group (C=O) in YG25 will react with the uncoordinated Pb in the perovskite. 2+ The YG25 treatment can significantly improve the PCE of the device to 100 V. OC and FF are improved, hysteresis is significantly reduced, and the storage stability of the device is improved.

[0024] Compared with the prior art, the present invention has the following characteristics and effects:

[0025] (1) By replacing the organic phosphonic acid molecule YG25, the indium tin oxide and perovskite layer can be more matched, effectively optimizing the interface between indium tin oxide and perovskite, and improving the flatness of the perovskite film, thereby optimizing the performance of the device.

[0026] (2) The raw materials for the preparation of YG25 are inexpensive, and the preparation method is simple and stable; it provides new possibilities for the interface optimization of perovskite solar cells.

[0027] (3) By replacing SnO with the organic phosphonic acid small molecule YG25 2 As an electron transport layer, it has significantly improved many aspects of the device, such as voltage and efficiency, thereby improving the performance of the battery.

[0028] The YG25 prepared by the present invention is used as an electron transport layer material, and the dynamic self-assembly of organic molecules in the film is realized. The prepared electron transport layer passivates the perovskite interface, which not only improves the upper surface microscopic morphology of the perovskite layer, but also the organic self-assembled small molecules on the upper interface of the electron transport layer and the ITO layer produce chemical bonding, slowing down the diffusion of the electrode into the device. The YG25 preparation method of the present invention is simple, easy to operate, low in cost, can be applied to perovskite solar cells, and has broad market prospects. Description of the drawings:

[0029] Figure 1 The schematic diagram is a synthetic route of the YG25 small molecule involved in the present invention.

[0030] Figure 2 The YG25 small molecule of the present invention 1 H NMR spectrum.

[0031] Figure 3 JV curves of different devices involved in the present invention. Specific implementation method:

[0032] The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings.

[0033] Embodiment 1:

[0034] This embodiment relates to a method for preparing a novel electron transport layer material YG25, comprising the following steps:

[0035] (3) Add diethyl (2-aminoethyl)phosphonate (5.5 mmol), 1,8-naphthalic anhydride (1 g, 5 mmol) and 4-dimethylaminopyridine (DMAP) (0.672 g, 5.5 mmol) into a three-necked flask and react at 70°C for 24 h; then dilute the reaction mixture with water and cool the mixture to 0°C; collect the resulting solid by vacuum filtration; wash the solid with water to obtain a crude product; the crude product is purified by column chromatography (DCM:PE=1:5, v / v) to obtain 1.5 g of white solid compound 3;

[0036]

[0037] (4) Compound 3 (0.9 g, 2.5 mmol) was dissolved in anhydrous 1,4-dioxane (20 mL) under a nitrogen atmosphere, and trimethylsilyl bromide (5.3 mL, 40 mmol) was added dropwise. The reaction was stirred at room temperature under a nitrogen atmosphere for 20 h. Then, methanol (10 mL) was added and stirring was continued for 3 h. Finally, excess distilled water was added dropwise until the solution became opaque and stirred overnight. The solution was filtered and the obtained solid was washed with water and dichloromethane. After filtering again, the obtained solid was washed with n-hexane to obtain 0.710 g of white powder, which was the electron transport layer material YG25. YG25 is an organic small molecule with a phosphonic acid group.

[0038]

[0039] In this example, the product YG25 was characterized by hydrogen spectrum. The results are as follows Figure 2 shown.

[0040] Embodiment 2:

[0041] This embodiment relates to a method for preparing a perovskite solar cell, and the specific steps are as follows:

[0042] (1) etching ITO, washing with detergent solution, deionized water, acetone, and ethanol for 20 minutes in sequence, and treating with ultraviolet ozone for 4 minutes; then dissolving the organic phosphonic acid molecule YG25 with a phosphonic acid group with DMSO to obtain a precursor solution with a concentration of 10 mol / mL, and ultrasonically treating for 5 minutes before spin coating;

[0043] (2) then spin-coating the organic phosphonic acid small molecule solution onto the treated ITO at a speed of 4000 rpm for 30 seconds, and then annealing at 110° C. for 20 minutes to obtain an electron transport layer;

[0044] (4) The device was immediately transferred to a glove box, and the perovskite solution that had been stirred overnight was spin-coated on the electron transport layer at a rotation speed of 4000 rpm for 30 s, and then annealed at 110 °C for 20 min;

[0045] (5) After cooling to room temperature, the Spiro-OMeTAD solution was spin-coated onto the perovskite layer at a speed of 1250 rpm for 30 s, and then annealed at 70 °C for 20 min;

[0046] (6) Then, 7 nm MoO was evaporated by vacuum evaporation. 3 , and then evaporate a 100nm silver electrode to obtain a perovskite solar cell device.

[0047] At AM1.5, 100mW / cm 2The current density-voltage test of the battery was tested under standard light, with traditional tin oxide as the electron transport layer as the control group. The JV performance curve is as follows Figure 3 And as shown in Table 1.

[0048] Table 1 Device performance

[0049]

[0050] As can be seen from Table 1, using organic phosphonic acid small molecule YG25 as the electron transport layer, the open circuit voltage V OC is 1.131V, short-circuit current density J SC 24.95mA / cm 2 The filling factor FF is 0.8292 and the photoelectric conversion efficiency is 23.41%, which further improves the device efficiency and device stability.

[0051] In summary, the novel phosphonic acid derivative small molecule electron transport layer material prepared by the present invention makes the film quality of perovskite on the indium tin oxide layer better, the flatness of the film is significantly improved, and the open circuit voltage and efficiency are increased to a certain extent, thereby improving the device performance of the perovskite solar cell.

Claims

1. A method for preparing a novel electron transport layer material YG25, characterized in that: The following steps are involved: (1) mixing 1,8-naphthalene dicarboxylic anhydride, diethyl (2-aminoethyl)phosphonate and 4-dimethylaminopyridine for reaction, then diluting the reaction mixture with water and cooling the mixture; collecting the obtained solid by vacuum filtration and washing to obtain a crude product; the crude product is purified by column chromatography to obtain a white solid which is compound 3; (2) Compound 3 was dissolved in anhydrous 1,4-dioxane under a nitrogen atmosphere, trimethylsilyl bromide was added, and the mixture was stirred under a nitrogen atmosphere to react; then, methanol was added and the stirring was continued; finally, distilled water was added and the mixture was stirred until the solution became opaque; After filtering and washing, a white powder is obtained, which is the electron transport layer material YG25.

2. The method for preparing the novel electron transport layer material YG25 according to claim 1, characterized in that: In step (1), the reaction temperature is 50-90° C. and the reaction time is 12-36 h.

3. The method for preparing the novel electron transport layer material YG25 according to claim 1, characterized in that: The reaction time after adding trimethylsilyl bromide in step (2) is 10-30 hours; the stirring time after adding methanol is 1-5 hours.

4. Application of the novel electron transport layer material YG25 prepared by the preparation method according to claim 1 in perovskite solar cells.

5. A method for preparing a perovskite solar cell, characterized in that: The following steps are involved: (1) Spin-coating the DMSO solution of YG25 prepared in claim 1 on the treated ITO, and annealing to obtain an electron transport layer; (2) Spin-coating a perovskite solution and a Spiro-OMeTAD solution on the electron transport layer in sequence, and annealing at corresponding temperatures; then, transferring the device to a vapor deposition station, and vapor-depositing MoO3 and a silver electrode in sequence.

6. The method for preparing a perovskite solar cell according to claim 5, characterized in that: In step 1), the concentration of the DMSO solution of YG25 is 10 mg / ml; the annealing temperature is 110° C., and the annealing time is 5 min to 10 min.

7. The method for preparing a perovskite solar cell according to claim 5, characterized in that: In step 1), the spin coating speed is 2000 rpm to 6000 rpm, and the spin coating time is 20 s to 60 s; before the spin coating starts, the DMSO solution of YG25 is allowed to adhere to the device surface and then allowed to stand in contact for 10 s to 30 s.

8. The method for preparing a perovskite solar cell according to claim 5, characterized in that: The perovskite layer is a film layer prepared by dissolving lead iodide, lead acetate, methylamine iodide and methylamine bromide in N,N-dimethylformamide in a material ratio of 0.4:0.6:2.05:0.15, and the solution concentration is 2 mol / mL.

9. A perovskite solar cell prepared by the preparation method according to any one of claims 5 to 8.

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