Perovskite precursor solution, perovskite solar cell and preparation method

Abstract

The invention discloses a perovskite precursor solution containing substituted aromatic ring group sulfonic acid, which comprises a perovskite material, an additive and an organic solvent, the additive is aromatic ring group sulfonic acid with a substituent group or a salt thereof, the aromatic ring is a benzene ring, a naphthalene ring or a pyrene ring, and the substituent group is one or more of H, halogen, C1-C4 alkenyl and C1-C4 alkyl. Polycyclic aromatic hydrocarbon (such as benzene, naphthalene and pyrene) is used as a framework, one sulfonic acid group instead of a sulfonyl group is introduced, and uncoordinated type defect passivation is realized through bonding with Pb < 2 + >; meanwhile, the electron push-pull characteristic of the substituent group is utilized, the Lewis acid-base amphoteric property is exerted, passivation of various types of defects is achieved, anchoring and passivation of multiple sites are achieved, the defects of the perovskite active layer can be remarkably reduced, non-radiative recombination can be reduced, and the performance and stability of the prepared perovskite solar cell in the large-scale preparation process are further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a perovskite precursor solution, a perovskite solar cell and a preparation method thereof. Background Art

[0002] Perovskite solar cells have become a research hotspot in the photovoltaic field due to their high photoelectric conversion efficiency and potential for low-cost fabrication. However, their large-scale application still faces multiple challenges. The inherent ionic crystal properties of perovskite materials and the low-temperature solution preparation process lead to the prevalence of vacancy defects, antisite defects, and deep energy level defects at interfaces in thin films. These defect states act as non-radiative recombination centers, significantly reducing carrier lifetimes and inducing ion migration (such as that of halide ions). This in turn leads to loss of open-circuit voltage, hysteresis, and deterioration of long-term stability, becoming a core bottleneck restricting device efficiency and stability. Additive engineering, through molecular design to optimize the film formation process and defect passivation, has become a key direction for improving device performance.

[0003] To improve the quality of perovskite films and device performance, researchers have tried a variety of defect passivation and crystallization control methods. For example, adding an appropriate amount of bulky organic cations, halide salts, or Lewis acid / base small molecules can passivate uncoordinated Pb during film formation. 2+ ions or reduce iodine vacancy defects, thereby reducing non-radiative recombination losses.

[0004] The Chinese patent document with publication number CN118146210A discloses an organic molecular additive, its preparation method and application, and provides an organic molecular additive, which introduces a pyridyl group, a pyrimidyl group or a triazine group into diphenylthiophene dioxide. When it is used as an additive for the perovskite layer of a perovskite solar cell, the sulfonyl group in diphenylthiophene dioxide can bind to the unbonded Pb on the perovskite surface. 2+ The combination can reduce lead defects and non-radiative recombination, and the sulfonyl group O=S=O can also effectively inhibit the influence of oxygen on perovskite solar cells and extend the service life of perovskite solar cells; the newly introduced pyridyl, pyrimidinyl or triazine group can further passivate the lead defects on the perovskite surface; the combined effect of the two greatly improves the film quality and stability of the perovskite, but its photoelectric conversion efficiency can only reach about 23%.

[0005] The above patent mentioned that the sulfonyl O=S=O structure and Pb 2+ The coordination effect of the Lewis base (S=O) can passivate the defects, reduce the non-radiative recombination of carriers, and improve the performance and stability of the corresponding solar cells. 2+The coordination bond formed cannot directly form a bond, which will affect the passivation effect and the final performance. We found that for FAPbI3 or FA prepared by blade coating / slit coating method x Cs 1-x In PbI3 perovskite films, unlike sulfonyl groups, the SOX bonds in the sulfonic acid groups can better combine with perovskite to passivate defects and achieve higher photoelectric conversion efficiency.

[0006] Chinese patent publication CN115701261A discloses a method for increasing the open-circuit voltage of solar cells using additives. This method targets solar cells containing perovskite materials and specifically involves adding an additive, sodium benzenesulfonate, to the perovskite material of the solar cell. By optimizing and controlling the amount of additive added, the method effectively increases the open-circuit voltage of solar cells compared to prior art methods. By introducing the additive into the perovskite material within the solar cell, the method can passivate internal device defects, reduce carrier loss, and effectively increase the open-circuit voltage of the perovskite solar cell.

[0007] Currently, large-scale perovskite active layer preparation is carried out in air. Nucleation, crystallization, annealing, and other processes also occur in air with oxygen and water vapor. As a result, the types of defects at the perovskite surface interface are more uncontrollable and diverse. Therefore, rational molecular structure design is needed to achieve simultaneous passivation of multiple defect types and sites to achieve improved performance and stability of perovskite solar cells prepared through large-scale processes. Summary of the Invention

[0008] In order to solve the above technical problems, the present invention provides a perovskite precursor solution containing substituted aromatic ring sulfonic acid, which is prepared by reacting with Pb 2+ Bonding is achieved to passivate uncoordinated defects, and at the same time, the push-pull electronic properties of the substituents are utilized to exert Lewis acid-base amphoteric properties to achieve passivation of various types of defects and achieve multi-site anchoring and passivation, which can significantly reduce defects in the perovskite active layer and interface, reduce non-radiative recombination, and improve the performance and stability of perovskite solar cells during large-scale preparation.

[0009] A perovskite precursor solution containing a substituted aromatic ring-based sulfonic acid comprises a perovskite material, an additive and an organic solvent. The additive is an aromatic ring-based sulfonic acid or a salt thereof with a substituent, the aromatic ring is a benzene ring, a naphthalene ring or a pyrene ring, and the substituent is one or more of H, a halogen, a C1-C4 alkenyl group, and a C1-C4 alkyl group.

[0010] In the present invention, a sulfonic acid or its salt with a substituent is added to the perovskite precursor solution, and a sulfonic acid group (-SO3H) is introduced instead of a sulfonyl group using a condensed ring aromatic hydrocarbon (such as benzene, naphthalene, pyrene) as the skeleton.2+ Bonding is used to passivate uncoordinated defects; at the same time, the push-pull electronic properties of the substituents are utilized to exert Lewis acid-base amphoteric properties to achieve passivation of various types of defects and achieve multi-site anchoring and passivation, which can significantly reduce defects in the perovskite active layer and interface, reduce non-radiative recombination, and further improve the performance and stability of perovskite solar cells during large-scale preparation.

[0011] Preferably, the substituted aromatic ring-based sulfonic acid or its salt is selected from any of the following structures: 、 、 、 、 、 、 .

[0012] Preferably, the concentration of the additive in the perovskite precursor solution is 0.1-5 mg / mL.

[0013] Preferably, the perovskite material is FA x Cs 1-x PbI3, where x=0.9~1.

[0014] Preferably, the concentration of the perovskite material in the perovskite precursor solution is 0.5-2 mmol / mL.

[0015] Preferably, the organic solvent is at least one of 2-methoxyethanol, N,N-dimethylformamide, dimethyl sulfoxide, dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, N,N-dimethylpropylene urea, and ethanolamine solution.

[0016] In the present invention, the organic solvent can dissolve the perovskite precursor and the additive, so that they can be evenly dispersed in the solution, thereby forming a perovskite precursor solution, which is beneficial to the subsequent preparation of the perovskite active layer.

[0017] The present invention also provides a method for preparing a perovskite precursor solution, comprising the following steps: dissolving lead iodide, cesium iodide, formamidine iodide, and methylamine chloride in an organic solvent according to a stoichiometric ratio of 1:(1-x):x:0.2~0.3 (wherein x=0.9~1) to obtain an undoped perovskite precursor solution; and adding an additive to the undoped perovskite precursor solution to obtain a perovskite precursor solution.

[0018] The present invention also provides a perovskite solar cell, comprising a substrate, a hole transport layer, a perovskite active layer, a passivation layer, an electron transport layer, a hole blocking layer and a metal electrode stacked in sequence, wherein the perovskite active layer is prepared from the above-mentioned perovskite precursor solution.

[0019] Preferably, the hole transport layer is NiO x A composite layer with a self-assembling molecule (SAM) material, wherein the self-assembling material is [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid.

[0020] Preferably, the passivation layer is propylenediamine dihydroiodide (PDAI2) or ethylenediamine dihydroiodide (EDAI2).

[0021] Preferably, the electron transport layer is a fullerene derivative layer, and the fullerene derivative is C 60 、PC 61 At least one of BM or ICBA, wherein the thickness of the electron transport layer is 5-50 nm.

[0022] Preferably, the hole blocking layer is NiO x 、NiO x / PTAA, self-assembled materials, NiO x / Self-assembly material, wherein the self-assembly material is [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid.

[0023] Preferably, the metal electrode is at least one of Ag, Au, Cu, and CuNi alloy, and has a thickness of 50 to 500 nm.

[0024] Preferably, the photoelectric conversion efficiency of the perovskite solar cell is ≥24%.

[0025] Compared with the prior art, the present invention has the following beneficial effects: The present invention adds a substituted aromatic ring sulfonic acid or its salt to the perovskite precursor solution, takes condensed ring aromatic hydrocarbons (such as benzene, naphthalene, pyrene) as the skeleton, introduces a sulfonic acid group (-SO3H) instead of a sulfonyl group, and reacts with Pb 2+ Bonding is used to passivate uncoordinated defects; at the same time, the push-pull electronic properties of the substituents are utilized to exert Lewis acid-base amphoteric properties to achieve passivation of various types of defects and achieve multi-site anchoring and passivation, which can significantly reduce defects in the perovskite active layer and interface, reduce non-radiative recombination, and improve the photoelectric conversion efficiency of perovskite solar cells. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below with reference to the examples, but the embodiments of the present invention are not limited to the following examples.

[0027] The raw materials used in the present invention are all commercially available.

[0028] Example 1 (1) Preparation of hole transport layer The FTO conductive glass substrate was ultrasonically cleaned for 15 minutes using conductive glass cleaning solution (purchased from Liaoning Youxuan New Energy Technology Co., Ltd.), deionized water, acetone, isopropyl alcohol, and ethanol in sequence, dried with nitrogen, and then treated with UV-ozone for 20 minutes. Spin-coated NiO x An aqueous solution of nanoparticles (concentration of 10 mg / mL) was spin-coated on the surface of an FTO conductive glass substrate at a speed of 3000 rpm / 30 s and annealed at 150 °C for 30 minutes. The spin-coated FTO conductive glass substrate was immersed in an ethanol solution containing [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid, i.e., Me-4PACz (concentration of 0.5 mg / mL) for 10 minutes and heated at 50 °C for 30 minutes. After being taken out and blown dry with nitrogen, a hole transport layer was obtained.

[0029] (2) Preparation of perovskite active layer Lead iodide (PbI2, 1.2 mmol), formamidine iodide (FAI, 1.2 mmol), and methylamine chloride (MACL, 0.35 mmol) were dissolved in 1 mL of DMF:NMP mixed solvent (volume ratio 8:1), and 3 mg of sodium 2,4,5-trichlorobenzenesulfonate was added as an additive. The mixture was stirred for 6 hours and filtered (0.22 μm PTFE filter membrane) for later use to obtain a perovskite precursor solution, in which the concentration of sodium 2,4,5-trichlorobenzenesulfonate was 3 mg / mL.

[0030] Placement step (1) Prepare the substrate of the hole transport layer so that its starting position is roughly flush with the bottom edge of the scraper, and add 15 μL of perovskite precursor solution to the gap between the scraper and the substrate. The scraper gap is 200 μm, the substrate temperature is 25°C, and the scraper movement speed is 3 mm / s. Start the machine, push the scraper from one side to the other, and turn on the air knife (air knife movement speed: 3 mm / s, use compressed air air knife (pressure 0.3 MPa) to remove excess solvent and promote crystallization. Then transfer the substrate containing the pre-dried perovskite active layer to a hot stage and anneal at 140°C for 30 minutes to form a FAPbI3 perovskite active layer with a thickness of about 500 nm, thereby obtaining a substrate containing a FAPbI3 perovskite active layer.

[0031] (3) Preparation of passivation layer The surface of the substrate containing the FAPbI3 perovskite active layer obtained in step (2) was spin-coated with PDAI2 isopropanol solution (concentration 0.5 mg / mL) at a spin-coating speed of 3000 rpm / 30 s and annealed at 100 °C for 5 minutes to obtain a substrate containing a passivation layer.

[0032] (4) Preparation of electron transport layer and hole blocking layer The surface of the substrate containing the passivation layer obtained in step (3) is successively spin-coated with PC61 BM solution (20 mg / mL chlorobenzene solution) and BCP solution (0.5 mg / mL isopropanol solution) were spin-coated at a speed of 2000 rpm and a spin-coating time of 30 s each time to obtain a substrate containing an electron transport layer and a hole blocking layer.

[0033] (6) Preparation of metal electrodes The Ag electrode was prepared by vacuum thermal evaporation method with a thickness of 150 nm to obtain a perovskite solar cell.

[0034] Examples 1 to 7 and Comparative Examples 1 to 4 The preparation method is the same as that of Example 1, with the differences shown in Table 1.

[0035] Table 1: Differences between Examples 1 to 7 and Comparative Examples 1 to 4

[0036] Sample analysis The performance of the perovskite solar cells of Examples 1 to 7 and Comparative Examples 1 to 4 was tested, and the specific method is as follows: The photocurrent density-voltage (JV) measurements of the perovskite solar cells prepared by the PCE test examples and comparative examples were obtained using a solar simulator (model SS-F5-3A, Enlitech, spectrum AM1.5G) and a universal source meter (Keithley 2400). The intensity of the AM1.5G spectrum was obtained by a certified standard silicon solar cell (model SRC-2020, Enlitech) at 100 mW cm -2 Test conditions: simulated light intensity of 100 mW cm -2 (AM1.5G) scan rate 0.1V s -1 (step size of 0.02 V, time delay of 200 ms), the scanning range was 1.2 V to -0.2 V.

[0037] Table 2: Performance test results of Examples 1 to 7 and Comparative Examples 1 to 4

[0038] As can be seen from Table 2, compared with no additives (Comparative Example 1) and the addition of sodium benzenesulfonate (Comparative Examples 2-4), the open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency of the perovskite solar cells prepared by adding substituted arylsulfonic acid or its salt to the perovskite precursor solution (Examples 1-7) of the present invention are improved.

[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A perovskite precursor solution containing a substituted aromatic ring sulfonic acid, comprising a perovskite material, an additive and an organic solvent, characterized in that: The additive is an aromatic ring-based sulfonic acid or its salt with a substituent, the aromatic ring is a benzene ring, a naphthalene ring or a pyrene ring, and the substituent is one or more of H, halogen, C1~C4 alkenyl, and C1~C4 alkyl.

2. The perovskite precursor solution containing substituted aromatic ring-based sulfonic acid according to claim 1, characterized in that: The aromatic ring-based sulfonic acid or its salt with a substituent is selected from any of the following structures: 、 、 、 、 、 、 。 3. The perovskite precursor solution containing substituted aromatic ring-based sulfonic acid according to claim 1, characterized in that: The concentration of the additive in the perovskite precursor solution is 0.1-5 mg / mL.

4. The perovskite precursor solution containing substituted aromatic ring-based sulfonic acid according to claim 1, characterized in that: The perovskite material is FA x Cs 1-x PbI3, where x=0.9~1.

5. The perovskite precursor solution containing substituted aromatic ring-based sulfonic acid according to claim 1, characterized in that: The concentration of the perovskite material in the perovskite precursor solution is 0.5-2 mmol / mL.

6. The perovskite precursor solution containing substituted aromatic ring-based sulfonic acid according to claim 1, characterized in that: The organic solvent is at least one of 2-methoxyethanol, N,N-dimethylformamide, dimethyl sulfoxide, dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, N,N-dimethylpropylene urea and ethanolamine solution.

7. A perovskite solar cell comprising a substrate, a hole transport layer, a perovskite active layer, a passivation layer, an electron transport layer, a hole blocking layer and a metal electrode stacked in sequence, characterized in that: The perovskite active layer is prepared from the perovskite precursor solution according to any one of claims 1 to 6.

8. The perovskite solar cell according to claim 7, characterized in that The hole transport layer is NiO x A composite layer with a self-assembling molecular material, wherein the self-assembling material is [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid.

9. The perovskite solar cell according to claim 7, characterized in that The electron transport layer is a fullerene derivative layer, and the fullerene derivative is C 60 、PC 61 At least one of BM or ICBA, wherein the thickness of the electron transport layer is 5-50 nm.

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