A perovskite solar cell and its preparation method

Abstract

The invention discloses a perovskite solar cell and a preparation method thereof, the preparation method comprising the steps of: sequentially coating a dense layer and a mesoporous layer on a pretreated conductive glass surface; dissolving iodomethane, lead iodide and chloromethylamine in a mixed solution of dimethyl sulfoxide and N,N-dimethylformamide to obtain a perovskite precursor solution, spin-coating the perovskite precursor solution onto the surface of the mesoporous layer to form a perovskite layer; dissolving magnesium benzoate salt in isopropyl alcohol to obtain a magnesium benzoate solution, spin-coating the magnesium benzoate solution onto the surface of the perovskite layer to form a magnesium benzoate passivation layer; coating a hole transport layer on the surface of the magnesium benzoate passivation layer, and depositing an electrode layer on the surface of the hole transport layer to obtain a perovskite solar cell. The present invention prepares a magnesium benzoate passivation layer using a magnesium benzoate solution, effectively improving the stability and photoelectric performance of solar cell devices.

Description

Technical Field

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

[0002] The photovoltaic field has witnessed the rapid rise of solution-processable hybrid organic-inorganic halide perovskites as contenders for efficient and affordable solar energy. In less than a decade, perovskites have come to dominate academic and industrial photovoltaic research, with perovskite solar cells (PSCs) now achieving solar-to-electrical conversion efficiencies (PCEs) >25%, comparable to commercial solar technologies.

[0003] Perovskite research has made significant progress, particularly in three-dimensional perovskites, whose PCEs have surpassed 25%. However, their poor stability to water, light, and heat has significantly hindered their commercialization. Compared to the typical lifespan of 25 years for silicon solar cells, the reported maximum lifespan of PSCs is only 10,000 hours, or approximately one year. For perovskites to achieve commercial application, not only high efficiency but also long-term stability are crucial.

[0004] Passivation is an effective strategy to reduce perovskite defects and inhibit ion movement. As early as the 1990s when the silicon solar cell industry began, dielectric coatings such as silicon nitride, silicon dioxide or titanium dioxide have become a universal solution for surface passivation. Surface passivation also plays a vital role in thin-film solar cells such as cadmium telluride and CuInO2. x Ga (1-x) Se2. Like these thin films, perovskites contain many intrinsic and interfacial defects. These defects make perovskites active and prone to decomposition, leading to non-radiative recombination, which in turn affects the performance and stability of solar cell devices. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a perovskite solar cell and a preparation method thereof, wherein a magnesium benzoate passivation layer is prepared using a magnesium benzoate solution, thereby effectively improving the stability and photoelectric performance of the solar cell device.

[0006] The present invention provides the following technical solutions:

[0007] In a first aspect, a perovskite solar cell is provided, comprising conductive glass and a dense layer, a mesoporous layer, a perovskite layer, a magnesium benzoate passivation layer, a hole transport layer and an electrode layer sequentially attached to the surface of the conductive glass from bottom to top.

[0008] In a second aspect, a method for preparing a perovskite solar cell is provided, comprising the following steps:

[0009] A dense layer and a mesoporous layer are sequentially coated on the surface of the pretreated conductive glass;

[0010] dissolving iodomethane, lead iodide, and chloromethylamine in a mixture of dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) to obtain a perovskite precursor solution, and spin-coating the perovskite precursor solution onto the surface of the mesoporous layer to form a perovskite layer;

[0011] dissolving magnesium benzoate salt in isopropyl alcohol to obtain a magnesium benzoate solution, and spin-coating the magnesium benzoate solution onto the surface of the perovskite layer to form a magnesium benzoate passivation layer;

[0012] A hole transport layer is coated on the surface of the magnesium benzoate passivation layer, and an electrode layer is deposited on the surface of the hole transport layer to obtain a perovskite solar cell.

[0013] Furthermore, the conductive glass is FTO conductive glass, and the pretreatment method is: sequentially using deionized water, glass cleaning agent, isopropyl alcohol, ethanol, and deionized water ultrasonic cleaning, then drying in an oven, and then treating with a UV-ozone device.

[0014] Furthermore, the glass cleaner is diluted with deionized water when used, and the volume ratio of the deionized water to the glass cleaner is 3:1.

[0015] Furthermore, the dense layer is prepared by adding diisopropoxy titanium diacetylacetonate into anhydrous n-butanol, shaking and dissolving the mixture, and then spin-coating the mixture onto the conductive glass, followed by drying to form the dense layer.

[0016] Furthermore, the volume ratio of the diisopropoxy titanium bisacetylacetonate to anhydrous n-butanol is 1:14-20.

[0017] Furthermore, the preparation method of the mesoporous layer is: preparing a mixed solution with titanium dioxide slurry and anhydrous ethanol, spin-coating the mixed solution on the surface of the dense layer, and annealing to form the mesoporous layer.

[0018] Furthermore, the volume ratio of the titanium dioxide slurry to anhydrous ethanol is 1:6-10.

[0019] The perovskite precursor solution is then spin-coated onto the surface of the mesoporous layer. Ether is then added as an antisolvent 20 seconds before the spin-coating is stopped. After the spin-coating is complete, the solution is annealed at 150°C for 5-10 minutes to form a perovskite layer. Spin-coating the perovskite precursor solution at room temperature forms a δ-phase perovskite, which has poor stability. Annealing can then form an α-phase perovskite, which improves the stability and photoelectric performance of the solar cell device.

[0020] Furthermore, the concentration of the prepared magnesium benzoate solution is 0.05-0.2 mmol / L.

[0021] Furthermore, after the magnesium benzoate solution is spin-coated onto the surface of the perovskite layer, it is placed on a heating table for annealing at a temperature of 110°C to 150°C for 5 to 15 minutes. Annealing helps to quickly evaporate the surface solvent, promotes crystallization, and improves the stability of the perovskite solar cell.

[0022] Furthermore, a hole transport layer Spiro-OMeTAD is spin-coated on the surface of the magnesium benzoate passivation layer, and an electrode is scraped out using γ-butyrolactone (GBL).

[0023] Furthermore, Au is deposited on the hole transport layer substrate using a vacuum evaporation device to form an Au electrode layer.

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

[0025] The present invention uses a magnesium benzoate solution to prepare a magnesium benzoate passivation layer. The benzene ring in the magnesium benzoate salt is a hydrophobic group, which leads to the formation of a dense structure, effectively blocking water and oxygen. In addition, the π-conjugated structure of the benzene ring promotes charge transfer, thereby significantly improving the stability and photoelectric performance of the solar cell device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of a perovskite solar cell in Example 1 of the present invention;

[0027] Marked in the figure: 1, FTO conductive glass, 2, dense layer, 3, mesoporous layer, 4, perovskite layer, 5, magnesium benzoate passivation layer, 6, hole transport layer, 7, electrode layer;

[0028] Figure 2 is a diagram of a perovskite solar cell device prepared in Example 1 of the present invention;

[0029] Figure 3 is the steady-state photoluminescence spectrum of the perovskite solar cells prepared in Examples 1, 4 and 5 of the present invention;

[0030] Figure 4 1 is the transient photoluminescence spectrum of the perovskite solar cells prepared in Examples 1, 4 and 5 of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0032] Example 1

[0033] This embodiment provides a method for preparing a perovskite solar cell, comprising the following steps:

[0034] (1) Pretreatment of FTO conductive glass: The FTO conductive glass was ultrasonically cleaned with deionized water, glass cleaner, isopropyl alcohol, ethanol, and deionized water for 20 minutes, followed by drying in a 120°C oven to remove surface moisture, and then treated with a UV-ozone device for 20 minutes. The glass cleaner was diluted with deionized water, and the volume ratio of deionized water to glass cleaner was 3:1.

[0035] (2) Preparation of dense layer: Add diisopropoxydiacetylacetonate titanium to anhydrous n-butanol, shake well to dissolve, and then spin-coat on the conductive glass. Dry to form a dense layer. The volume ratio of diisopropoxydiacetylacetonate titanium to anhydrous n-butanol is 1:17.

[0036] (3) Preparation of mesoporous layer: Titanium dioxide slurry and anhydrous ethanol are prepared into a mixed solution, which is spin-coated on the surface of the dense layer and annealed to form a mesoporous layer. The volume ratio of titanium dioxide slurry to anhydrous ethanol is 1:8.

[0037] (4) Preparation of perovskite layer: iodomethane, lead iodide and chloromethylamine were dissolved in a mixture of DMSO and DMF and stirred for 12 h to obtain a perovskite precursor solution. The perovskite precursor solution was spin-coated onto the surface of the mesoporous layer at a speed of 3000 rpm. Ether was added as an anti-solvent 20 s before the spin coating was stopped. After the spin coating was completed, the mixture was annealed at 150°C for 10 min to form a perovskite layer.

[0038] (5) Preparation of magnesium benzoate passivation layer: Magnesium benzoate salt was dissolved in isopropyl alcohol to obtain a 0.1 mmol / L magnesium benzoate solution, which was spin-coated onto the surface of the perovskite layer at a speed of 3000 rpm, and then placed on a heating table for annealing at 130°C for 10 min to form a magnesium benzoate passivation layer.

[0039] (6) Preparation of hole transport layer: Spiro-OMeTAD hole transport layer was spin-coated on the surface of the magnesium benzoate passivation layer, and the FTO electrode was scraped out with GBL.

[0040] (7) Preparation of electrode layer: Au is deposited on the hole transport layer substrate using a vacuum evaporation device to form an Au electrode layer.

[0041] Figure 1 The structure diagram of the prepared perovskite solar cell includes FTO conductive glass and a dense layer, a mesoporous layer, a perovskite layer, a magnesium benzoate passivation layer, a hole transport layer and an Au electrode layer attached to the surface of the FTO conductive glass from bottom to top.

[0042] Figure 2 The prepared perovskite solar cell device.

[0043] Example 2

[0044] This embodiment provides a method for preparing a perovskite solar cell, comprising the following steps:

[0045] (1) Pretreatment of FTO conductive glass: The FTO conductive glass was ultrasonically cleaned with deionized water, glass cleaner, isopropyl alcohol, ethanol, and deionized water for 20 minutes, followed by drying in a 120°C oven to remove surface moisture, and then treated with a UV-ozone device for 20 minutes. The glass cleaner was diluted with deionized water, and the volume ratio of deionized water to glass cleaner was 3:1.

[0046] (2) Preparation of dense layer: Add diisopropoxydiacetylacetonate titanium to anhydrous n-butanol, shake well to dissolve, then spin-coat on the conductive glass and dry to form a dense layer. The volume ratio of diisopropoxydiacetylacetonate titanium to anhydrous n-butanol is 1:14.

[0047] (3) Preparation of mesoporous layer: Titanium dioxide slurry and anhydrous ethanol are prepared into a mixed solution, which is spin-coated on the surface of the dense layer and annealed to form a mesoporous layer. The volume ratio of titanium dioxide slurry to anhydrous ethanol is 1:6.

[0048] (4) Preparation of perovskite layer: iodomethane, lead iodide and chloromethylamine were dissolved in a mixture of DMSO and DMF and stirred for 12 h to obtain a perovskite precursor solution. The perovskite precursor solution was spin-coated onto the surface of the mesoporous layer at a speed of 3000 rpm. Ether was added as an anti-solvent 20 s before the spin coating was stopped. After the spin coating was completed, the mixture was annealed at 150°C for 5 min to form a perovskite layer.

[0049] (5) Preparation of magnesium benzoate passivation layer: Magnesium benzoate salt was dissolved in isopropyl alcohol to obtain a 0.05 mmol / L magnesium benzoate solution, which was spin-coated onto the surface of the perovskite layer at a speed of 3000 rpm, and then placed on a heating table for annealing at 110°C for 15 min to form a magnesium benzoate passivation layer.

[0050] (6) Preparation of hole transport layer: Spiro-OMeTAD hole transport layer was spin-coated on the surface of the magnesium benzoate passivation layer, and the FTO electrode was scraped out with GBL.

[0051] (7) Preparation of electrode layer: Au is deposited on the hole transport layer substrate using a vacuum evaporation device to form an Au electrode layer.

[0052] Example 3

[0053] (1) Pretreatment of FTO conductive glass: The FTO conductive glass was ultrasonically cleaned with deionized water, glass cleaner, isopropyl alcohol, ethanol, and deionized water for 20 minutes, followed by drying in a 120°C oven to remove surface moisture, and then treated with a UV-ozone device for 20 minutes. The glass cleaner was diluted with deionized water, and the volume ratio of deionized water to glass cleaner was 3:1.

[0054] (2) Preparation of dense layer: Add diisopropoxydiacetylacetonate titanium to anhydrous n-butanol, shake well to dissolve, and then spin-coat on the conductive glass. Dry to form a dense layer. The volume ratio of diisopropoxydiacetylacetonate titanium to anhydrous n-butanol is 1:20.

[0055] (3) Preparation of mesoporous layer: Titanium dioxide slurry and anhydrous ethanol are prepared into a mixed solution, the mixed solution is spin-coated on the surface of the dense layer, and annealed to form a mesoporous layer. The volume ratio of titanium dioxide slurry to anhydrous ethanol is 1:10.

[0056] (4) Preparation of perovskite layer: iodomethane, lead iodide and chloromethylamine were dissolved in a mixture of DMSO and DMF and stirred for 12 h to obtain a perovskite precursor solution. The perovskite precursor solution was spin-coated onto the surface of the mesoporous layer at a speed of 3000 rpm. Ether was added as an anti-solvent 20 s before the spin coating was stopped. After the spin coating was completed, the mixture was annealed at 150°C for 8 min to form a perovskite layer.

[0057] (5) Preparation of magnesium benzoate passivation layer: Magnesium benzoate salt was dissolved in isopropyl alcohol to obtain a 0.2 mmol / L magnesium benzoate solution, which was spin-coated onto the surface of the perovskite layer at a speed of 3000 rpm, and then placed on a heating table and annealed at 150°C for 5 min to form a magnesium benzoate passivation layer.

[0058] (6) Preparation of hole transport layer: Spiro-OMeTAD hole transport layer was spin-coated on the surface of the magnesium benzoate passivation layer, and the FTO electrode was scraped out with GBL.

[0059] (7) Preparation of electrode layer: Au is deposited on the hole transport layer substrate using a vacuum evaporation device to form an Au electrode layer.

[0060] Example 4

[0061] This embodiment provides a method for preparing a perovskite solar cell, which is different from Example 1 in that the concentration of the magnesium benzoate solution prepared in step (5) is 0.05 mmol / L.

[0062] Example 5

[0063] This embodiment provides a method for preparing a perovskite solar cell, which is different from Example 1 in that the concentration of the magnesium benzoate solution prepared in step (5) is 0.2 mmol / L.

[0064] Comparative Example 1

[0065] This embodiment provides a method for preparing a perovskite solar cell, which is different from Example 1 in that the concentration of the magnesium benzoate solution prepared in step (5) is 0.3 mmol / L.

[0066] Comparative Example 2

[0067] This embodiment provides a method for preparing a perovskite solar cell, which is different from Example 1 in that there is no annealing process in step (5).

[0068] Comparative Example 3

[0069] This embodiment provides a method for preparing a perovskite solar cell, which is different from Example 1 in that step (5) is omitted, that is, a passivation layer is not prepared.

[0070] Performance Characterization

[0071] The performance of the perovskite solar cells prepared in Examples 1-5 and Comparative Examples 1-3 was tested using a solar simulator, as shown in Table 1 below.

[0072] Table 1 Performance data of perovskite solar cells in Examples 1-5 and Comparative Examples 1-3

[0073] <![CDATA[V oc (V)]]> <![CDATA[J sc (mA / cm 2 )]]> FF(%) PCE (%) Example 1 1.032 24.92 78.42 20.19 Example 2 1.010 25.00 79.02 19.91 Example 3 1.008 25.68 73.76 19.10 Example 4 1.041 25.22 79.12 20.68 Example 5 1.021 25.42 78.88 20.40 Comparative Example 1 1.010 26.54 70.47 18.91 Comparative Example 2 0.988 25.85 73.97 18.89 Comparative Example 3 0.985 26.06 73.55 18.88

[0074] In Table 1, V oc is the open circuit voltage, J sc is the short-circuit current, FF is the fill factor, and PCE is the photoelectric conversion efficiency.

[0075] It can be seen from Table 1 that the solar cell devices in Examples 1-5 have excellent performance in various aspects, while the solar cell devices in Comparative Examples 1-3 have relatively poor performance.

[0076] Figure 3 The steady-state photoluminescence spectra of the perovskite solar cells prepared in Examples 1, 4 and 5 are shown in FIG. Figure 3 It can be seen that the device passivated with 0.05-0.2 mmol / L magnesium benzoate solution exhibits excellent PL fluorescence intensity, indicating that the number of carriers increases after passivation, leading to enhanced device performance. In addition, when the concentration of magnesium benzoate solution increases to 0.2 mmol / L, the device begins to show a decrease in PL fluorescence intensity.

[0077] Figure 4The transient photoluminescence spectra of the perovskite solar cells prepared in Examples 1, 4 and 5 are shown in FIG. Figure 4 It can be seen that the device passivated with 0.05-0.2 mmol / L magnesium benzoate solution has a longer carrier lifetime, which is beneficial for carrier transport, thereby improving the performance of the device. Examples 2 and 3 also show similar performance, which will not be described in detail here.

[0078] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that: The following steps are involved: A dense layer and a mesoporous layer are sequentially coated on the surface of the pretreated conductive glass; Dissolving iodomethane, lead iodide, and chloromethylamine in a mixture of dimethyl sulfoxide and N,N-dimethylformamide to obtain a perovskite precursor solution, spin-coating the perovskite precursor solution onto the surface of the mesoporous layer, adding ether as an anti-solvent 20 seconds before stopping the spin coating, and annealing at 150° C. for 10 minutes after the spin coating is completed to form a perovskite layer; dissolving magnesium benzoate salt in isopropyl alcohol to obtain a magnesium benzoate solution having a concentration of 0.05-0.2 mmol / L, and spin-coating the magnesium benzoate solution onto the surface of the perovskite layer to form a magnesium benzoate passivation layer; A hole transport layer is coated on the surface of the magnesium benzoate passivation layer, and an electrode layer is deposited on the surface of the hole transport layer to obtain a perovskite solar cell.

2. The method for preparing a perovskite solar cell according to claim 1, wherein: The conductive glass is FTO conductive glass, and the pretreatment method is: sequentially using deionized water, glass cleaning agent, isopropyl alcohol, ethanol, and deionized water ultrasonic cleaning, then drying in an oven, and then treating with an ultraviolet-ozone device.

3. The method for preparing a perovskite solar cell according to claim 1, wherein: The dense layer is prepared by adding diisopropoxy titanium bisacetylacetonate to anhydrous n-butanol, shaking and dissolving the mixture, and then spin-coating the mixture on conductive glass, followed by drying to form a dense layer; the volume ratio of the diisopropoxy titanium bisacetylacetonate to the anhydrous n-butanol is 1:14-20.

4. The method for preparing a perovskite solar cell according to claim 1, wherein: The preparation method of the mesoporous layer is as follows: titanium dioxide slurry and anhydrous ethanol are prepared into a mixed solution, the mixed solution is spin-coated on the surface of the dense layer, and annealing is performed to form the mesoporous layer; the volume ratio of the titanium dioxide slurry to anhydrous ethanol is 1:6-10.

5. The method for preparing a perovskite solar cell according to claim 1, wherein: The magnesium benzoate solution is spin-coated onto the surface of the perovskite layer, and then placed on a heating platform for annealing at a temperature of 110° C. to 150° C. for 5 to 15 minutes.

6. The method for preparing a perovskite solar cell according to claim 1, wherein: The hole transport layer Spiro-OMeTAD was spin-coated on the surface of the magnesium benzoate passivation layer, and the electrode was scraped out using γ-butyrolactone.

7. The method for preparing a perovskite solar cell according to claim 1, wherein: Au is deposited on the hole transport layer substrate using a vacuum evaporation device to form an Au electrode layer.

8. A perovskite solar cell, characterized in that: The perovskite solar cell comprises conductive glass and a dense layer, a mesoporous layer, a perovskite layer, a magnesium benzoate passivation layer, a hole transport layer and an electrode layer sequentially attached to the surface of the conductive glass from bottom to top; the perovskite solar cell is prepared by the method according to any one of claims 1 to 7.

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