Rare earth perovskite quantum dot, preparation method thereof and application of rare earth perovskite quantum dot in solar cell

Abstract

The invention discloses a rare earth perovskite quantum dot and a preparation method and application thereof in a solar cell, and belongs to the technical field of perovskite solar cells, and the preparation method comprises the following steps: mixing and stirring erbium salt and ammonium chloride in a solvent in a nitrogen atmosphere, after primary heating and heat preservation heating, adding an oleylamine solution, and continuing heat preservation heating to obtain a rare earth perovskite quantum dot solution; and adding a cesium oleate precursor after secondary temperature rise and heating to a specified temperature, immediately putting into an ice-water bath for cooling, centrifuging and washing the obtained product, and dissolving in chlorobenzene to obtain the rare earth perovskite quantum dot. The rare earth perovskite quantum dot provided by the invention is simple to prepare, is suitable for preparing various cell perovskite layers, and has good universality. Meanwhile, the solar cell provided by the invention has good stability and excellent commercial prospects.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell technology, and particularly relates to a rare earth perovskite quantum dot, its preparation method, and its application in solar cells. Background Art

[0002] With the continuous development of sustainable energy across all sectors of society, solar cells, which convert solar energy into electrical energy, have become a hot research topic, among which perovskite solar cells are gradually gaining public attention. Perovskite solar cells have been extensively studied due to their advantages such as simple processing, abundant materials, high absorption coefficient, tunable bandgap, low exciton binding energy, and excellent polar carrier transport performance. However, perovskite solar cells also contain numerous defects, some of which form impurity levels within the perovskite bandgap. These defects that generate impurity levels are classified into deep-level defects and shallow-level defects. Deep-level defects generate non-radiative recombination centers, causing carrier loss when the perovskite is exposed to light. While shallow-level defects do not generate significant non-radiative recombination centers that cause severe carrier loss, they can still lead to ion migration under the influence of light, heat, or electricity, affecting the structure of the perovskite.

[0003] The most serious problem lies in the large amount of lead iodide present during the perovskite layer preparation process. Because excess lead iodide promotes the growth and crystallization of perovskite films, most perovskite precursors contain excessive lead iodide. However, once the perovskite has grown, the excess lead iodide remains on the surface of the perovskite film, promoting its decomposition under light and adversely affecting its stability.

[0004] Rare-earth quantum dots (QDs) offer advantages such as stable performance, tunable luminescence properties, and adjustable size. The oleic acid-oleylamine ligands used in their fabrication effectively block the influence of water and oxygen molecules in the air on perovskite. The QDs themselves can passivate perovskite defects and regulate grain boundaries in perovskite rich in defects and susceptible to interference from water and oxygen molecules. QD modification of the perovskite surface can improve the quality of the perovskite film, thereby enhancing device performance and stability. Currently, there are many applications of quantum dots, especially rare-earth QDs, to improve the quality of perovskite films. By controlling the concentration of quantum dots, the passivation effect on perovskite can be significantly enhanced.

[0005] Therefore, how to provide a method for improving the performance of perovskite layers in solar cells using rare earth quantum dots is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a rare-earth perovskite quantum dot, its preparation method, and its application in solar cells.

[0007] To achieve the above objectives, the present invention provides the following technical solutions:

[0008] A method for preparing rare-earth perovskite quantum dots includes the following steps:

[0009] Under a nitrogen atmosphere, erbium salt and ammonium chloride are mixed and stirred in a solvent. After heating once and holding at that temperature, oleylamine solution is added and the heating is continued. Then, after heating a second time to the specified temperature, cesium oleate precursor is added and the mixture is immediately placed in an ice-water bath to cool. The resulting product is centrifuged, washed, and then dissolved in chlorobenzene to obtain the rare earth perovskite quantum dots.

[0010] Preferably, the erbium salt is erbium acetate; and / or

[0011] The solvent is obtained by mixing octadecene and oleic acid in a volume ratio of 10:2.

[0012] This solvent ensures that erbium and chlorine are fully dissolved in the solvent in ionic form, and prevents moisture and oxygen in the air from reacting with the ions and causing element loss.

[0013] Preferably, the single heating and holding process involves heating to 150°C and holding for 30 minutes.

[0014] The continued heat preservation and heating refers to continuing heat preservation and heating at 150°C for 30 minutes;

[0015] Preferably, the secondary heating is to raise the temperature to 260°C.

[0016] The above conditions ensure that the elemental ions remain in a highly active state during the material preparation process, so that they can rapidly combine to form the desired quantum dots during cooling.

[0017] More preferably, the method for preparing the rare earth perovskite quantum dots includes the following steps;

[0018] (1) Weigh 0.1g of erbium acetate hydrate powder and 0.08g of ammonium chloride, add 10ml of octadecene and 2ml of oleic acid mixed solution, adjust the stirring speed to 750r / min, pass nitrogen gas at room temperature, stir for 10min under nitrogen atmosphere, then heat to 150℃ and keep heated for 30min, add 1ml of oleylamine solution, continue to keep heated at 150℃ for 30min, then heat to 260℃, add 1mL of cesium oleate precursor at 100℃, and then put it in an ice water bath to cool to room temperature.

[0019] (2) After cooling, the solution is centrifuged at 9000 r / min for 10 min to remove the supernatant. Then, toluene and ethyl acetate are added to obtain a mixed solution at a volume ratio of 1:1. After thorough mixing and dissolution, the solution is centrifuged at 9000 r / min for 10 min. The above dissolution and centrifugation steps are repeated twice.

[0020] (3) After removing the supernatant after centrifugation, add 5 ml of chlorobenzene to the centrifuge tube and dissolve it completely to obtain rare earth perovskite quantum dots. Let it stand for 24 hours for later use.

[0021] Preferably, the method for preparing the cesium oleate precursor includes the following steps:

[0022] Cesium salt was stirred in a solvent under a nitrogen atmosphere, heated to 120°C and held for 30 minutes, and then heated to 150°C to obtain the cesium oleate precursor.

[0023] Preferably, the cesium salt is cesium carbonate; and / or

[0024] The solvent is obtained by mixing octadecene and oleic acid in a volume ratio of 10:1.25.

[0025] More preferably, the method for preparing the cesium oleate precursor includes the following steps:

[0026] Weigh 0.4 g of cesium carbonate powder and add it to a mixed solution of 10 ml octadecene and 1.25 ml oleic acid. Adjust the stirring speed to 750 r / min, purge with nitrogen at room temperature, and stir for 10 min under a nitrogen atmosphere. Then raise the temperature to 120 °C and hold for 30 min, and continue heating to 150 °C to obtain a 0.11 mol / L cesium oleate precursor, which can be bottled for later use. Before use, heat the cesium oleate precursor to 100 °C. When not in use, store at 4 °C.

[0027] Preferably, the cesium oleate precursor is heated to 100°C before use.

[0028] Rare earth perovskite quantum dots prepared by the method described above.

[0029] Application of rare earth perovskite quantum dots in perovskite solar cells.

[0030] A perovskite solar cell includes a perovskite layer comprising the rare-earth perovskite quantum dots of claim 7.

[0031] Preferably, the perovskite layer is obtained by spin-coating the rare earth perovskite quantum dots onto a perovskite film that has been heated at 150°C for 1 min, and then annealing it at 150°C for 15 min.

[0032] Compared with the prior art, the present invention has the following advantages and technical effects:

[0033] The present invention relates to a method for coating rare-earth perovskite quantum dots onto a heated perovskite solar cell. This coating utilizes excess lead iodide on the perovskite film surface to promote secondary crystallization of the perovskite layer, resulting in shallower grain boundaries. This effectively suppresses nonradiative recombination caused by deep-level defects and ion migration caused by shallow-level defects, thereby improving carrier mobility and promoting charge extraction. Furthermore, the rare-earth perovskite quantum dots provided by this invention are simple to prepare and applicable to the preparation of perovskite layers for various batteries, exhibiting good versatility. Simultaneously, the solar cell provided by this invention demonstrates excellent stability and promising commercial prospects. Attached Figure Description

[0034] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0035] Figure 1 This is a scanning electron microscope (SEM) image of the cross-sectional morphology of the perovskite solar cell based on rare-earth perovskite quantum dot pretreatment obtained in Example 2.

[0036] Figure 2 The image shows the morphology of the perovskite layer obtained in Example 2 using a transmission electron microscope.

[0037] Figure 3 These are scanning electron microscope images of the surface morphology of the perovskite layers obtained in Example 2 and Comparative Example 1;

[0038] Figure 4 The conductivity curves of the perovskite solar cells obtained in Example 2 and Comparative Example 1 are shown.

[0039] Figure 5 The JV curves are for the perovskite solar cells obtained in Example 2 and Comparative Example 1.

[0040] Figure 6 The graphs show the stability of the perovskite layers obtained in Example 2 and Comparative Example 1 in air. Detailed Implementation

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels;

[0044] Unless otherwise specified, room temperature or normal temperature in the embodiments of the present invention refers to 25±3℃.

[0045] Example 1

[0046] A method for preparing rare-earth perovskite quantum dots includes the following steps:

[0047] 1. Preparation of the precursor cesium oleate;

[0048] (1-1) Weigh 0.4g of cesium carbonate powder into a 100ml three-necked flask and place a 1cm high-temperature rotor inside. Then add a mixed solution of 10ml octadecene and 1.25ml oleic acid. Place the three-necked flask on a heating mantle and connect the middle flask opening to the heating mantle's thermocouple via a rubber stopper, ensuring the thermocouple is within the liquid surface of the octadecene and oleic acid mixture without contacting the flask wall. Use the other two flask openings as the nitrogen inlet and outlet, respectively. Connect the outlet to water via a conduit. Observe the size and speed of bubbles in the water to determine the flow rate of nitrogen entering the three-necked flask. Adjust the nitrogen flow rate so that one bubble is generated every 2-3 seconds.

[0049] (1-2) Adjust the stirring speed to 750 r / min, stir with nitrogen gas at room temperature for 10 min, then raise the temperature to 120℃ and hold for 30 min, and continue heating to 150℃ to obtain a cesium oleate precursor with a concentration of 0.11 mol / L, which can be bottled for later use. Before use, heat the cesium oleate precursor to 100℃ for later use, and store it at 4℃ when not in use.

[0050] 2. Preparation of rare earth perovskite quantum dots;

[0051] (2-1) Weigh 0.1g of erbium acetate hydrate powder and 0.08g of ammonium chloride into a 100ml three-necked flask, place a 1cm high-temperature rotor into it, add 10ml of a mixed solution of octadecene and 2ml of oleic acid, connect it to the apparatus in step 1, and adjust the nitrogen flow rate so that a bubble is generated every 2-3 seconds.

[0052] (2-2) Adjust the stirring speed to 750 r / min, stir with nitrogen gas at room temperature for 10 min, then heat to 150℃ and keep it heated for 30 min, add 1 ml of oleylamine solution, continue to keep it heated at 150℃ for 30 min, then heat to 260℃, add 1 mL of the 100℃ cesium oleate precursor obtained in step 1, and immediately put the three-necked flask into an ice water bath to cool to room temperature.

[0053] (2-3) After cooling, centrifuge the solution at 9000 r / min for 10 min, remove the supernatant, and then add toluene and ethyl acetate in a volume ratio of 1:1 to obtain a mixed solution. After fully mixing and dissolving, continue to centrifuge at 9000 r / min for 10 min. Repeat the above dissolution and centrifugation steps twice.

[0054] (2-4) After removing the supernatant after centrifugation, add 5 ml of chlorobenzene to the centrifuge tube and dissolve it completely to obtain rare earth perovskite quantum dots. Transfer them to a clean brown vial and let them stand for 24 hours for later use.

[0055] Example 2

[0056] A perovskite solar cell based on rare-earth perovskite quantum dot pretreatment includes an electron transport layer, a perovskite layer based on rare-earth perovskite quantum dots obtained in Example 1, a hole transport layer, and an electrode layer stacked sequentially. The preparation method specifically includes the following steps:

[0057] (1) Preparation of electron transport layer: 2.5 wt% tin dioxide ethylene glycol methyl ether colloidal dispersion was coated on the FTO surface, and then spin-coated on the FTO surface at 4000 r / min for 30 s, and annealed at 150℃ for 20 min to obtain an electron transport layer with a thickness of 40 nm.

[0058] (2) Preparation of perovskite layer: 0.172g formamidinium hydroiodate, 0.507g lead iodide, 0.0224g methylammonium bromide, 0.0734g potassium bromide, and 0.0015588g cesium iodide were dissolved in a mixed solution of 800mL dimethylformamide and 240mL dimethyl sulfoxide to prepare a perovskite precursor. The perovskite precursor was drop-coated onto the electron transport layer prepared in step (1), and then spin-coated into a uniform thin film. After annealing at 150°C for 1 min, a perovskite thin film with a thickness of 400nm was obtained. The rare earth perovskite quantum dots obtained in Example 1 were then coated onto the perovskite thin film annealed for 1 min at 4000r / min. The film was then annealed at 150°C for 15 min to obtain a perovskite layer with a thickness of 450nm based on the rare earth perovskite quantum dots obtained in Example 1.

[0059] (3) Preparation of hole transport layer: Spiro-OmeTAD is used as hole material to coat the perovskite layer obtained in step (2), and spin-coated on the perovskite surface pretreated with quantum dots for 30s at a speed of 3000r / min to obtain a hole transport layer with a thickness of 150nm.

[0060] (4) Electrode preparation: A silver electrode layer with a thickness of 100 nm is deposited on the surface of the hole transport layer obtained in step (3) to complete the preparation of perovskite solar cells based on rare earth perovskite quantum dot pretreatment.

[0061] Comparative Example 1

[0062] A perovskite solar cell, differing from Example 2 in that the perovskite layer is not pretreated with rare-earth perovskite quantum dots. The specific preparation method includes the following steps:

[0063] (1) Preparation of electron transport layer: 2.5 wt% tin dioxide ethylene glycol methyl ether colloidal dispersion was coated on the FTO surface, and then spin-coated on the FTO surface at 4000 r / min for 30 s, and annealed at 150℃ for 20 min to obtain an electron transport layer with a thickness of 40 nm.

[0064] (2) Preparation of perovskite layer: 0.172g formamidinium hydroiodate, 0.507g lead iodide, 0.0224g methylammonium bromide, 0.0734g potassium bromide, and 0.0015588g cesium iodide were dissolved in a mixed solution of 800mL dimethylformamide and 240mL dimethyl sulfoxide to prepare a perovskite precursor. The perovskite precursor was drop-coated onto the electron transport layer prepared in step (1), and then spin-coated into a uniform thin film. After annealing at 150℃ for 15min, a perovskite layer with a thickness of 400nm was obtained.

[0065] (3) Preparation of hole transport layer: Spiro-OmeTAD is used as hole material to coat the perovskite layer obtained in step (2), and spin-coated on the perovskite surface pretreated with quantum dots for 30s at a speed of 3000r / min to obtain a hole transport layer with a thickness of 150nm.

[0066] (4) Electrode preparation: A silver electrode layer with a thickness of 100 nm is deposited on the surface of the hole transport layer obtained in step (3) to complete the preparation of the perovskite solar cell.

[0067] Comparative Example 2

[0068] A method for preparing rare-earth perovskite quantum dots, differing from Example 1 in that erbium acetate is not added in step (2-1), specifically including the following steps:

[0069] 1. Preparation of the precursor cesium oleate;

[0070] (1-1) Weigh 0.4g of cesium carbonate powder into a 100ml three-necked flask and place a 1cm high-temperature rotor inside. Then add a mixed solution of 10ml octadecene and 1.25ml oleic acid. Place the three-necked flask on a heating mantle and connect the middle flask opening to the heating mantle's thermocouple via a rubber stopper, ensuring the thermocouple is within the liquid surface of the octadecene and oleic acid mixture without contacting the flask wall. Use the other two flask openings as the nitrogen inlet and outlet, respectively. Connect the outlet to water via a conduit. Observe the size and speed of bubbles in the water to determine the flow rate of nitrogen entering the three-necked flask. Adjust the nitrogen flow rate so that one bubble is generated every 2-3 seconds.

[0071] (1-2) Adjust the stirring speed to 750 r / min, stir with nitrogen gas at room temperature for 10 min, then heat to 120℃ and hold for 30 min, then continue heating to 150℃ to obtain the cesium oleate precursor, which can be bottled for later use. Before use, heat the cesium oleate precursor to 100℃ for later use, and store it at 4℃ when not in use.

[0072] 2. Preparation of rare earth perovskite quantum dots;

[0073] (2-1) Weigh 0.08g of ammonium chloride and place it in a three-necked flask with a volume of 100ml. Place a 1cm high-temperature rotor in the flask, add 10ml of a mixed solution of octadecene and 2ml of oleic acid, connect it to the apparatus in step 1, and adjust the nitrogen flow rate so that a bubble is generated every 2-3 seconds.

[0074] (2-2) Adjust the stirring speed to 750 r / min, stir with nitrogen gas at room temperature for 10 min, then heat to 150℃ and keep it heated for 30 min, add 1 ml of oleylamine solution, continue to keep it heated at 150℃ for 30 min, then heat to 260℃, add 1 mL of the 100℃ cesium oleate precursor obtained in step 1, and immediately put the three-necked flask into an ice water bath to cool to room temperature.

[0075] (2-3) After cooling, the solution is centrifuged at 9000 r / min for 10 min to remove the supernatant. Then, toluene and ethyl acetate are added to obtain a mixed solution at a volume ratio of 1:1. After thorough mixing, the solution is centrifuged at 9000 r / min for 10 min. The above dissolution and centrifugation steps are repeated twice.

[0076] (2-4) After removing the supernatant after centrifugation, add 5 ml of chlorobenzene to the centrifuge tube and dissolve it completely to obtain rare earth perovskite quantum dots. Transfer them to a clean brown vial and let them stand for 24 hours for later use.

[0077] Comparative Example 3

[0078] A perovskite solar cell based on rare earth perovskite quantum dot post-processing differs from Example 2 only in that the perovskite layer in step (2) is a perovskite layer based on rare earth perovskite quantum dots obtained by different annealing times. Step (2) specifically includes the following steps:

[0079] (2) Preparation of perovskite layer: 0.172g formamidinium hydroiodate, 0.507g lead iodide, 0.0224g methylammonium bromide, 0.0734g potassium bromide, and 0.0015588g cesium iodide were dissolved in a mixed solution of 800mL dimethylformamide and 240mL dimethyl sulfoxide to prepare a perovskite precursor. The perovskite precursor was drop-coated onto the electron transport layer prepared in step (1), and then spin-coated into a uniform thin film. After annealing at 150℃ for 15min, a perovskite thin film with a thickness of 400nm was obtained. The rare earth perovskite quantum dots obtained in Comparative Example 2 were then coated onto the perovskite thin film annealed for 15min at 4000r / min. The film was then annealed at 150℃ for 1min to obtain a perovskite layer with a thickness of 400nm based on the rare earth perovskite quantum dots obtained in Comparative Example 2.

[0080] Technical effects:

[0081] 1. Performance Characterization:

[0082] Figure 1 The image shows a scanning electron microscope (SEM) image of the cross-sectional morphology of the perovskite solar cell based on rare-earth perovskite quantum dot pretreatment obtained in Example 2; the presence of the rare-earth perovskite quantum dot pretreatment layer can be seen from the image.

[0083] Figure 2 The image shows a transmission electron microscope (TEM) image of the morphology of the perovskite layer obtained in Example 2. The image shows the morphology of hexagonal quantum dots in the perovskite, indicating the presence of quantum dots in the pretreated perovskite.

[0084] Figure 3 The images show scanning electron microscope (SEM) images of the surface morphology of the perovskite layers obtained in Example 2 and Comparative Example 1. As can be seen from the images, the grain boundaries on the surface of the perovskite film are blurred after treatment with rare earth perovskite quantum dots. This indicates that secondary crystallization of the perovskite film promotes grain boundary repair, which is beneficial for reducing defects at the grain boundaries.

[0085] 2. Electrical properties:

[0086] Figure 4 The graph shows the conductivity curves of the perovskite solar cells obtained in Example 2 and Comparative Example 1. As can be seen from the graph, the perovskite solar cells pretreated with rare earth perovskite quantum dots have high conductivity, indicating that the pretreatment of rare earth perovskite quantum dots can more effectively promote charge transport, and the device has good performance.

[0087] Figure 5The figures show the JV curves of the perovskite solar cells obtained in Example 2 and Comparative Example 1. The figures show that the devices prepared by the pretreatment process have higher current response and higher photoelectric conversion efficiency, indicating that rare earth perovskite quantum dots can effectively improve the performance of perovskite solar cells.

[0088] Figure 6 The graph shows the stability of the perovskite layers obtained in Example 2 and Comparative Example 1 in air. As can be seen from the graph, the pretreated perovskite film can still have more than 90% light response after being stored in air for more than 2500 hours, indicating that the perovskite solar cell of the present invention has a longer stability in practical applications.

[0089] 3. Device parameters

[0090] The short-circuit current, open-circuit voltage, fill factor, and photoelectric conversion efficiency of the perovskite solar cells obtained in Example 2 and Comparative Examples 1-2 were tested, and the data are shown in Table 1:

[0091] Table 1 Device parameters of perovskite solar cells

[0092]

[0093] As can be seen from the table, the perovskite solar cell pretreated with rare earth perovskite quantum dots in Example 2 has the highest short-circuit current, open-circuit voltage, fill factor, and photoelectric conversion efficiency, indicating that the perovskite solar cell prepared by the present invention has good device performance.

[0094] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for preparing rare earth perovskite quantum dots, characterized in that, Includes the following steps: Under a nitrogen atmosphere, erbium salt and ammonium chloride are mixed and stirred in a solvent. After heating once and holding at that temperature, oleylamine solution is added and the heating is continued. Then, after heating a second time to the specified temperature, cesium oleate precursor is added and the mixture is immediately placed in an ice-water bath to cool. The resulting product is centrifuged, washed, and then dissolved in chlorobenzene to obtain the rare earth perovskite quantum dots.

2. The method for preparing rare earth perovskite quantum dots according to claim 1, characterized in that, The erbium salt is erbium acetate; and / or, The solvent is obtained by mixing octadecene and oleic acid in a volume ratio of 10:

2.

3. The method for preparing rare earth perovskite quantum dots according to claim 1, characterized in that, The first heating and holding process involves heating to 150°C and holding for 30 minutes. The continued heat preservation and heating refers to continuing the heat preservation and heating at 150°C for 30 minutes.

4. The method for preparing rare earth perovskite quantum dots according to claim 1, characterized in that, The second heating is to raise the temperature to 260°C.

5. The method for preparing rare earth perovskite quantum dots according to claim 1, characterized in that, The concentration of the cesium oleate precursor is 0.11 mol / L, and its preparation method includes the following steps: Cesium salt was stirred in a solvent containing oleic acid under a nitrogen atmosphere, heated to 120°C and held for 30 minutes, and then heated to 150°C to obtain the cesium oleate precursor.

6. The method for preparing rare earth perovskite quantum dots according to claim 5, characterized in that, The cesium salt is cesium carbonate; and / or, The solvent containing oleic acid is obtained by mixing octadecene and oleic acid in a volume ratio of 10:1.

25. Preferably, the cesium oleate precursor is heated to 100°C before use.

7. Rare earth perovskite quantum dots prepared by the preparation method according to any one of claims 1-6.

8. The application of rare earth perovskite quantum dots as described in claim 7 in perovskite solar cells.

9. A perovskite solar cell, comprising a perovskite layer, characterized in that, The perovskite layer includes the rare earth perovskite quantum dots as described in claim 7.

10. The solar cell according to claim 9, characterized in that, The perovskite layer is obtained by spin-coating the rare earth perovskite quantum dots onto a perovskite film that has been annealed at 150°C for 1 min, and then annealing it at 150°C for 15 min.

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