Perovskite cell electron transport layer preparation method and perovskite cell

Abstract

The invention discloses a preparation method of an electron transport layer of a perovskite battery and the perovskite battery, and belongs to the technical field of perovskite batteries. The electron transport layer is prepared through the first deposition and the second deposition, during the first deposition, the reducing agent is added, and the precursor solution of the electron transport layer is controlled to be in a low-concentration oxygen content state, so that the electron transport layer thin film which begins to be deposited can obtain oxygen vacancies with relatively high concentration, thereby being beneficial to extraction and migration of electrons; and during the second deposition, hydrogen peroxide is added, so that the oxygen content in the electron transport layer precursor solution is increased, and the oxygen vacancy concentration in the electron transport layer thin film deposited later is reduced, thereby improving the stability of the perovskite cell. And the electron transport layer is prepared through two times of deposition, so that the stability of the perovskite cell is improved, and the cell efficiency is improved at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite cells, and in particular to a method for preparing an electron transport layer of a perovskite cell and a perovskite cell. Background Art

[0002] Chemical bath deposition is a commonly used method for preparing electron transport layer SnO 2 Thin film method, by controlling the deposition conditions, can obtain thin films with specific properties. 2 During the deposition process, the oxygen content of the solution has an important influence on the properties of the deposited film. For example, a chemical bath solution with a low oxygen content can produce SnO with a high oxygen vacancy concentration. 2 This is beneficial for improving the electron extraction and migration of the electron transport layer.

[0003] In the existing technology, the properties of the film are usually controlled by changing the conditions of chemical bath deposition, such as temperature, time, solution composition, etc. For example, the composition of the solution can be changed by replacing non-volatile thioglycolic acid with volatile oxalic acid, and combined with hydrogen peroxide interface modification to obtain SnO with better stability. 2 In addition, there are some technologies that change the properties of thin films by adding specific additives to the solution.

[0004] However, there are still some problems with existing technologies in improving the stability of perovskite cells. First, existing technologies often require complex operations, which increases production costs. Second, while existing technologies improve battery stability, they may sacrifice other battery properties, such as efficiency. Finally, existing technologies have limited effects in improving battery stability and require further research and improvement. Summary of the invention

[0005] The main purpose of the present invention is to provide a method for preparing an electron transport layer of a perovskite cell and a perovskite cell, so as to solve the technical problem that it is difficult to simultaneously improve the stability and photoelectric conversion efficiency of the perovskite cell.

[0006] To achieve the above object, the present invention provides a method for preparing an electron transport layer of a perovskite battery, comprising the following steps: First deposition: placing the substrate in a first electron transport layer precursor solution for first deposition, wherein the first electron transport layer precursor solution contains a reducing agent; Second deposition: placing the substrate after the first deposition in a second electron transport layer precursor solution, performing a second deposition to form an electron transport layer, wherein the second electron transport layer precursor solution contains hydrogen peroxide.

[0007] In some embodiments of the present invention, the reducing agent includes at least one of potassium sulfite and sodium sulfite.

[0008] In some embodiments of the present invention, the first electron transport layer precursor solution includes a solvent, in which the amount of the reducing agent added is (1~5) mg / 100 mL; and / or the second electron transport layer precursor solution includes a solvent, in which the amount of the hydrogen peroxide added is (0.5~1.5) ml / 100 mL.

[0009] In some embodiments of the present invention, the first deposition time is 3h~4h; and / or the second deposition time is 4h~5h.

[0010] In some embodiments of the present invention, the temperature of the first deposition is 85°C-95°C; and / or the temperature of the second deposition is 85°C-95°C.

[0011] In some embodiments of the present invention, after the second deposition is completed, an annealing treatment is further performed, wherein the annealing temperature is 160° C. to 170° C.; and / or the annealing time is 0.5 h to 1 h.

[0012] In some embodiments of the present invention, and / or, the first electron transport layer precursor solution includes SnO 2 and TiO 2 At least one of; And / or, the second electron transport layer precursor solution includes SnO 2 and TiO 2 At least one of .

[0013] In some embodiments of the present invention, after the first deposition is completed, the hydrogen peroxide is added to the first electron transport layer precursor solution to obtain the second electron transport layer precursor solution; The present invention also provides a perovskite battery prepared by the above-mentioned method for preparing the perovskite battery.

[0014] In some embodiments of the present invention, the perovskite cell comprises, from bottom to top, a transparent conductive oxide layer, the electron transport layer, a perovskite active layer, a hole transport layer and a metal electrode.

[0015] The beneficial effects that can be achieved by the present invention are: The present invention performs two depositions when preparing the electron transport layer. During the first deposition, a reducing agent is added to the electron transport layer precursor solution, and the electron transport layer precursor solution is controlled to be in a low oxygen concentration state, so that the electron transport layer film that is just deposited can obtain oxygen vacancies with a higher concentration, which is beneficial to the extraction and migration of electrons, thereby achieving the purpose of improving battery efficiency. During the second deposition, hydrogen peroxide is added to the electron transport layer precursor solution, the oxygen content in the electron transport layer precursor solution is increased, and the oxygen vacancy concentration in the electron transport layer film deposited later is reduced, thereby improving the stability of the perovskite battery. Through two depositions, the stability of the perovskite battery is improved while its battery efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0017] Figure 1 This is a current density-voltage (V) curve of the perovskite battery in Example 1 of the present invention.

[0018] Figure 2 It is a current density voltage (V) curve diagram of the perovskite battery of comparative example 2 and example 2 of the present invention. DETAILED DESCRIPTION

[0019] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0021] In the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0022] The present invention provides a method for preparing an electron transport layer of a perovskite battery, comprising the following steps: First deposition: placing the substrate in a first electron transport layer precursor solution for first deposition, wherein the first electron transport layer precursor solution contains a reducing agent; Second deposition: placing the substrate after the first deposition in a second electron transport layer precursor solution, performing a second deposition to form an electron transport layer, wherein the second electron transport layer precursor solution contains hydrogen peroxide.

[0023] The present invention improves the preparation method of the electron transport layer of the perovskite battery. The electron transport layer is prepared by two depositions. During the first deposition, a reducing agent is added to the electron transport layer precursor solution. The electron transport layer precursor solution is controlled to be in a low oxygen concentration state, so that the electron transport layer film that is just deposited can obtain oxygen vacancies with a higher concentration, which is beneficial to the extraction and migration of electrons and achieves the purpose of improving the battery efficiency. During the second deposition, hydrogen peroxide is added to the electron transport layer precursor solution to increase the oxygen content in the electron transport layer precursor solution, so that the oxygen vacancy concentration in the electron transport layer film deposited later is reduced, thereby improving the stability of the perovskite battery. The electron transport layer is prepared by two depositions, and the stability of the perovskite battery is improved while improving its battery efficiency.

[0024] In the present invention, the reducing agent has reducing properties and can reduce the oxygen content in the electron transport layer precursor solution, thereby enabling the deposited electron transport layer film to obtain a high concentration of oxygen vacancies, thereby facilitating the extraction and migration of electrons, thereby achieving the purpose of improving battery efficiency.

[0025] In some embodiments, the reducing agent includes potassium sulfite and sodium sulfite. The above types of reducing agents have good reducing properties, which are beneficial to reducing the oxygen content in the electron transport layer precursor solution, and promoting the deposited electron transport layer film to obtain a high concentration of oxygen vacancies, which is beneficial to the extraction and migration of electrons, thereby achieving the purpose of improving battery efficiency. Moreover, it is not easy to react with other components in the electron transport layer precursor solution to affect the performance of the electron transport layer.

[0026] In the present invention, hydrogen peroxide can increase the oxygen content in the electron transport layer precursor solution, reduce the oxygen vacancy concentration in the electron transport layer film deposited later, and thus improve the stability of the perovskite battery.

[0027] In some embodiments, the first electron transport layer precursor solution includes a solvent, in which the amount of the reducing agent added is (1-5) mg / 100 mL, which may be 1 mg / 100 mL, 2 mg / 100 mL, 3 mg / 100 mL, 4 mg / 100 mL, 5 mg / 100 mL, etc. By adjusting the amount of the reducing agent added, the stability of the battery is further improved to meet the actual application requirements.

[0028] In some embodiments, the second electron transport layer precursor solution includes a solvent, in which the amount of hydrogen peroxide added is (0.5-1.5) ml / 100 mL, which may be 0.5 mg / 100 mL, 1 mg / 100 mL, 1.5 mg / 100 mL, etc. By adjusting the amount of hydrogen peroxide added, the stability of the battery is further improved to meet the actual application requirements.

[0029] In some embodiments, the first deposition time is 3 h to 4 h.

[0030] In some embodiments, the temperature of the first deposition is 85°C to 95°C.

[0031] In some embodiments, the second deposition time is 1 h to 2 h.

[0032] In some embodiments, the temperature of the second deposition is 85°C-95°C.

[0033] In some embodiments, after the second deposition is completed, annealing is further performed, and after the last deposition is completed, annealing is performed again, which is beneficial to the fusion of the electron transport layer thin film formed by the first deposition and the second deposition.

[0034] In some embodiments, the annealing temperature is 160°C to 170°C.

[0035] In some embodiments, the annealing time is 0.5 h to 1 h.

[0036] The present invention prepares the electron transport layer by a deposition method. Therefore, the electron transport layer material includes types suitable for the deposition method, including SnO 2 and TiO 2 At least one of .

[0037] In some embodiments, the first electron transport layer precursor solution includes SnO 2 and TiO 2At least one of the second electron transport layer precursor solution includes SnO 2 and TiO 2 At least one of .

[0038] In some embodiments, the first electron transport layer precursor solution and the second electron transport layer precursor solution both contain a solvent, and the solvent is used to disperse the electron transport layer material and the reducing agent and hydrogen peroxide. The solvent includes water and / or an organic solvent, and the organic solvent includes at least one of ethanol, acetone, and dimethyl sulfoxide.

[0039] In the present invention, the electron transport layer material can be dispersed in a solvent to prepare an electron transport layer solution matrix, and then a reducing agent is added to the electron transport layer solution matrix to obtain a first electron transport layer precursor solution, and hydrogen peroxide is added to the electron transport layer solution matrix to obtain a second electron transport layer precursor solution.

[0040] In the present invention, the electron transport layer solution matrix of the first electron transport layer precursor solution and the second electron transport layer precursor solution is the same, which can reduce the difference between the electron transport layer films obtained by the first deposition and the second deposition, making them easy to fuse to obtain the electron transport layer.

[0041] Exemplarily, the electron transport layer material can be dispersed in a solvent to obtain an electron transport layer solution matrix, the same electron transport layer solution matrix can be divided into two parts, a reducing agent is added to one part to form a first electron transport layer precursor solution, and hydrogen peroxide is added to the other part to form a second electron transport layer precursor solution, and then the substrate is deposited for the first time in the above-mentioned first electron transport layer precursor solution. After the first deposition is completed, the substrate is placed in the above-mentioned second electron transport layer solution for a second deposition. In this embodiment, the matrix of the first electron transport layer precursor solution and the second electron transport layer precursor solution is the same, which can reduce the difference between the electron transport layer films obtained by the first deposition and the second deposition, making them easy to fuse to obtain the electron transport layer, and mass production can be achieved.

[0042] Exemplarily, the electron transport layer material can also be dispersed in a solvent to prepare two identical electron transport layer solution matrices, and then a reducing agent is added to one of the electron transport layer solution matrices to obtain a first electron transport layer precursor solution, and hydrogen peroxide is added to the other electron transport layer solution matrix to obtain a second electron transport layer precursor solution, and then the substrate is deposited for the first time in the first electron transport layer precursor solution. After the first deposition is completed, the substrate is placed in the above-mentioned second electron transport layer solution for a second deposition. In this embodiment, the matrices of the first electron transport layer precursor solution and the second electron transport layer precursor solution are the same, which can reduce the difference between the electron transport layer films obtained by the first deposition and the second deposition, making them easy to fuse to obtain the electron transport layer, and mass production can be achieved.

[0043] Exemplarily, a first electron transport layer precursor solution containing a reducing agent may be prepared first, and after the first deposition is completed, hydrogen peroxide is continued to be added to the first electron transport layer precursor solution to obtain a second electron transport layer precursor solution, and the second electron transport layer precursor solution is used to complete the second deposition. In this embodiment, the first electron transport layer precursor solution and the second electron transport layer precursor solution have similar compositions, which can easily reduce the difference between the electron transport layer films obtained by the first deposition and the second deposition, making them easy to fuse to obtain the electron transport layer, and can reduce the waste of raw materials and reduce the number of experimental steps.

[0044] In some embodiments, the method for preparing the electron transport layer of the perovskite cell of the present invention comprises the following steps: First deposition: placing the substrate in a first electron transport layer precursor solution for first deposition, wherein the first electron transport layer precursor solution contains a reducing agent; Second deposition: adding hydrogen peroxide to the first electron transport layer precursor solution after the first deposition to obtain a second electron transport layer precursor solution, placing the substrate after the first deposition in the second electron transport layer precursor solution, and performing a second deposition to form an electron transport layer.

[0045] In some embodiments, the substrate includes a glass substrate and a transparent conductive oxide layer formed on a surface of the glass substrate, and an electron transport layer is deposited on a surface of the transparent conductive oxide layer.

[0046] In the present invention, the material for preparing the transparent conductive oxide layer can be selected from common materials in the art, and in some embodiments, includes at least one of indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), and fluorine-doped tin oxide (FTO).

[0047] In some embodiments, the substrate further includes an interface modification layer commonly used in the art, such as a passivation layer, disposed between the transparent conductive oxide layer and the electron transport layer, for modifying the electron transport layer. Therefore, in this embodiment, it is necessary to deposit the electron transport layer on the surface of the interface modification layer of the substrate.

[0048] The present invention further provides a perovskite cell and a method for preparing the same. The method for preparing the perovskite cell includes the steps in the method for preparing the electron transport layer as described above. The prepared perovskite cell contains the electron transport layer as described above and at least has all the beneficial effects of the electron transport layer as described above.

[0049] The perovskite battery of the present invention also includes the preparation of other functional layers, such as the preparation of a hole transport layer, a perovskite active layer, a metal electrode, etc. The preparation of the above functional layers can refer to the common methods in the art and will not be repeated here.

[0050] In some embodiments, the perovskite cell includes, from bottom to top, a glass substrate, a transparent oxide layer, an electron transport layer of the present invention, a perovskite active layer, a hole transport layer, and a metal electrode.

[0051] In some embodiments, an interface modification layer, such as a passivation layer, may be designed between the perovskite active layer and the hole transport layer to reduce charge recombination at the interface between the perovskite active layer and the hole transport layer and improve the photoelectric conversion efficiency and stability of the battery.

[0052] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following specific embodiments are only used to explain the present invention, and are not used to limit the present invention.

[0053] Example 1 The preparation of the perovskite cell of Example 1 is as follows: Prepare substrate The FTO glass substrate protected by a high temperature resistant tape was cleaned by ultrasonic cleaning in anionic surfactant solution, deionized water, ethanol and isopropanol for 15 min respectively. After the cleaning, it was blown dry with a nitrogen flow for later use.

[0054] Deposition of electron transport layer First deposition: 2.5 g urea, 550 mg SnCl 2 ·2H 2 O, 200 mL of ultrapure water, 2.5 mL of HCl, 50 μL of thioglycolic acid (TGA), and 10 mg of K 2 SO 3Add to a 500 mL beaker and stir to obtain the first electron transport layer precursor solution. Place the FTO glass vertically in the first electron transport layer precursor solution, place the beaker in a 90°C water bath to start the timing reaction, and the reaction deposition is 3.5 h.

[0055] Second deposition: After the first deposition reaction reaches 3.5 h, add 3 mL of H 2 O 2 The second electron transport layer precursor solution was formed, and the FTO glass was allowed to continue to react for 5 h, then the FTO glass was taken out, the high temperature resistant tape of the FTO glass was torn off, and the glass was ultrasonically cleaned with deionized water and isopropanol for 5 min respectively. After being blown dry with a nitrogen flow, the glass was placed on a hot stage and annealed at 170 ° C for 1 h to form an electron transport layer.

[0056] Deposition of the perovskite layer Accurately weigh 1.383 g PbI 2 , which was dissolved in 2 mL of anhydrous DMF / DMSO mixed solvent (v:v=9:1) and stirred at 60 °C for 2 h to prepare PbI 2 Solution: A mixture of 180 mg FAI, 18 mg MABr and 20 mg MACl was accurately weighed, dissolved in 2 mL anhydrous isopropanol, and stirred at room temperature until transparent to prepare a FAI / MABr / MACl solution.

[0057] The perovskite active layer was deposited in two steps: the FTO glass with the electron transport layer deposited was placed in a UV ozone treatment machine for 20 min. In a glove box with a nitrogen atmosphere, 80 µL of PbI 2 The solution was statically spin-coated on the electron transport layer substrate with the specific parameters of 1500 rpm for 30 s, and then annealed at 70 °C for 1 min to obtain PbI 2 Thin film, waiting for PbI 2 After the film was completely cooled, 150 μL of FAI / MABr / MACl solution was statically spin-coated on the PbI 2 The perovskite film was annealed at 170°C for 10 min in a glove box with low humidity (RH<30%) to prepare a perovskite active layer.

[0058] Deposition of passivation layer 15 mg of 2-phenylethylamine hydroiodide (PEAI) was accurately weighed and dissolved in 3 mL of anhydrous isopropanol. The solution was mixed by oscillating. In a glove box with a nitrogen atmosphere, 100 μL of the solution was statically spin-coated on the perovskite active layer. The specific spin-coating parameters were 5000 rpm for 30 s. After the spin-coating process, no further annealing treatment was required, and the hole transport layer was directly deposited.

[0059] Deposition of hole transport layer Accurately weigh 90 mg of Spiro-OMeTAD, add 44 μL of lithium bis(trifluoromethane)sulfonyl imide (LiTFSI) stock solution (260 mg Li-TFSI dissolved in 1 ml of anhydrous acetonitrile), 37 μL of 4-tert-butylpyridine (tBP) and 1 mL of anhydrous chlorobenzene, and mix the solution by ultrasonic treatment for 5 min. In a glove box with a nitrogen atmosphere, 60 μL of the solution was dynamically spin-coated on the passivation layer film, with the specific spin-coating parameters of 2000 rpm, 30 s, without further annealing.

[0060] Deposition of metal back electrode The FTO substrate with the hole transport layer deposited on it was de-edged and placed in a vacuum coating machine, where a 100 nm Ag electrode was evaporated to finally obtain a complete perovskite battery device.

[0061] Example 2 Example 2 A perovskite battery is prepared by referring to the preparation method of Example 1, except that the perovskite active layer is prepared by a one-step method in Example 2, as follows: Accurately weigh 19.5 mg CsI, 15.9 mg RbI, 8.4 mg MABr, 219.5 mg FAI, 656.9 mg PbI2 and 27.5 mg PbBr 2 The powder mixture was dissolved in 1 mL of anhydrous DMF / DMSO mixed solvent (v:v=4:1) and shaken for 2 h using a vortex shaker to completely dissolve it to obtain a perovskite precursor solution. The components of the precursor solution were Rb 0.05 Cs 0.05 MA 0.05 FA 0.85 Pb(I 0.95 Br 0.05 ) 3 , with a concentration of 1.5 M.

[0062] The perovskite film was prepared by a one-step method, with anhydrous chlorobenzene as the anti-solvent. The FTO glass deposited with the electron transport layer was placed in a UV ozone treatment machine and treated with ozone for 20 min. In a glove box with a nitrogen atmosphere, 70 μL of the perovskite precursor solution was spin-coated on the electron transport layer substrate. The spin coating was divided into two processes, with specific parameters of 1000 rpm, 10 s and 3000 rpm, 30 s. In the second process, 150 μL of anhydrous chlorobenzene was quickly added at 15 s. After the spin coating, the film was annealed at 100 ° C for 10 min to form a perovskite active layer.

[0063] Example 3 Example 3: A perovskite battery was prepared by referring to Example 1, but the difference is that when preparing the electron transport layer, the chemical bath solution in Example 3 contains K 2 SO 3 and H 2 O 2 The amount of K contained in the chemical bath solution in Example 3 is different. 2 SO 3 and H 2 O 2 The amounts are 2 mg and 1 mL respectively.

[0064] Example 4 Example 4 A perovskite battery was prepared by referring to Example 1, but the difference is that when preparing the electron transport layer, the K contained in the chemical bath solution of Example 3 2 SO 3 and H 2 O 2 The amount of K contained in the chemical bath solution in Example 4 is different. 2 SO 3 and H 2 O 2 The amounts were 10 mg and 3 mL respectively.

[0065] Example 5 Example 5 A perovskite battery was prepared by referring to Example 2, but the difference is that when preparing the electron transport layer, the chemical bath solution in Example 5 contains K 2 SO 3 and H 2 O 2 The amount of K contained in the chemical bath solution in Example 5 is different. 2 SO 3 and H 2 O 2 The amounts are 2 mg and 1 mL respectively.

[0066] Example 6 Example 6: A perovskite battery was prepared by referring to Example 2, but the difference is that when preparing the electron transport layer, the chemical bath solution in Example 6 contains K 2 SO 3 and H 2 O 2 The amount of K contained in the chemical bath solution in Example 6 is different. 2 SO 3 and H 2 O 2 The amounts were 10 mg and 3 mL respectively.

[0067] Comparative Example 1 Comparative Example 1 A perovskite battery was prepared by referring to the preparation method of Example 1, except that the preparation steps of the electron transport layer were as follows: 2.5 g of urea, 550 mg of SnCl 2 ·2H 2 O, 200 mL of ultrapure water, 2.5 mL of HCl and 50 μL of TGA were added into a 500 mL beaker and stirred evenly to obtain an electron transport layer precursor solution.

[0068] After placing the FTO glass vertically in the electron transport layer precursor solution, place the beaker in a 90°C water bath and start timing. When the reaction has been going on for 5 hours, take out the FTO glass, tear off the high-temperature resistant tape, and then ultrasonically clean it with deionized water and isopropanol for 5 minutes respectively. After drying with a nitrogen flow, place it on a hot stage and anneal it at 170°C for 1 hour to form an electron transport layer.

[0069] Comparative Example 2 Comparative Example 2 A perovskite battery was prepared by referring to the preparation method of Example 1, except that the preparation steps of the electron transport layer were as follows: 2.5 g of urea, 550 mg of SnCl 2 ·2H 2 O, 200 mL of ultrapure water, 2.5 mL of HCl and 50 μL of TGA were added into a 500 mL beaker and stirred evenly to obtain an electron transport layer precursor solution.

[0070] After placing the FTO glass vertically in the electron transport layer precursor solution, place the beaker in a 90°C water bath and start timing. When the reaction is carried out for 5 hours, take out the FTO glass, tear off the high-temperature resistant tape, and then ultrasonically clean it with deionized water and isopropanol for 5 minutes respectively. After drying with a nitrogen flow, place it on a hot stage and anneal it at 170°C for 1 hour to form an electron transport layer. Performance Testing 1. The storage stability of the devices of Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Examples 3 to 6 under a relative humidity of 30%-40% is compared. The changes in device efficiency from 0 to 7 days are summarized in Table 1.

[0071] 2. Determine the Voc open circuit voltage (V) and Jsc short circuit current density (mA / cm2) of the perovskite battery devices obtained in Examples 1 to 6 and Comparative Examples 1 to 2. 2 ), FF filling factor (%), PCE photoelectric conversion efficiency (%), the results are shown in Table 2. In addition, the data comparison between Example 1 and Comparative Example 1 can also be seen. Figure 1 The data comparison between Example 2 and Comparative Example 2 also shows Figure 2 .

[0072] Table 1 Efficiency of the embodiments and comparative examples stored for different time periods

[0073] It can be seen from Table 1 that the device of Example 1 still maintains more than 95% of the initial efficiency after being stored for 7 days, the efficiency of the device of Comparative Example 1 decays to less than 80% of the initial efficiency, and the device of Example 2 still maintains more than 95% of the initial efficiency after being stored for 7 days, and the efficiency of the device of Comparative Example 2 decays to about 80% of the initial efficiency. It can be seen that adding a reducing agent and hydrogen peroxide to deposit an electron transport layer is beneficial to improving the stability of the perovskite battery. Similarly, the perovskite batteries obtained by adding a reducing agent and hydrogen peroxide to deposit an electron transport layer in Examples 3 to 6 also obtain good stability.

[0074] Table 2 Performance comparison of perovskite cells obtained in Examples and Comparative Examples

[0075] Combination Figure 1 , Figure 2 As can be seen from Table 2, the devices prepared in Examples 1 to 6 all achieved good photoelectric conversion efficiency, while the photoelectric conversion efficiency of the perovskite cells prepared in Comparative Example 1, in which a reducing agent and hydrogen peroxide were not added to prepare an electron transport layer relative to Example 1, and Comparative Example 2, in which a reducing agent and hydrogen peroxide were not added to prepare an electron transport layer relative to Example 2, decreased relative to Examples 1 and 2, respectively.

[0076] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing an electron transport layer of a perovskite battery, characterized in that: The following steps are involved: First deposition: placing the substrate in a first electron transport layer precursor solution for first deposition, wherein the first electron transport layer precursor solution contains a reducing agent; Second deposition: placing the substrate after the first deposition in a second electron transport layer precursor solution, performing a second deposition to form an electron transport layer, wherein the second electron transport layer precursor solution contains hydrogen peroxide.

2. The method for preparing the electron transport layer of the perovskite battery according to claim 1, characterized in that: The reducing agent includes at least one of potassium sulfite and sodium sulfite.

3. The method for preparing the electron transport layer of the perovskite battery according to claim 1, characterized in that: The first electron transport layer precursor solution includes a solvent, in which the reducing agent is added in an amount of (1-5) mg / 100 mL; And / or, the second electron transport layer precursor solution includes a solvent, and the added amount of the hydrogen peroxide in the solvent is (0.5-1.5) ml / 100 mL.

4. The method for preparing the electron transport layer of the perovskite battery according to claim 1, characterized in that: The time of the first deposition is 3h~4h; and / or the time of the second deposition is 1h~2h.

5. The method for preparing the electron transport layer of the perovskite battery according to claim 1, characterized in that: The temperature of the first deposition is 85°C to 95°C; and / or the temperature of the second deposition is 85°C to 95°C.

6. The method for preparing the electron transport layer of the perovskite battery according to claim 1, characterized in that: After the second deposition is completed, an annealing treatment is further performed, wherein the annealing temperature is 160° C. to 170° C.; and / or the annealing time is 1 h to 2 h.

7. The method for preparing the electron transport layer of a perovskite battery according to claim 1, characterized in that: The first electron transport layer precursor solution includes at least one of SnO2 and TiO2; And / or, the second electron transport layer precursor solution includes at least one of SnO2 and TiO2.

8. The method for preparing the electron transport layer of a perovskite battery according to any one of claims 1 to 7, characterized in that: After the first deposition is completed, the hydrogen peroxide is added to the first electron transport layer precursor solution to obtain the second electron transport layer precursor solution.

9. A perovskite battery, characterized in that: It comprises an electron transport layer prepared by the method for preparing an electron transport layer of a perovskite cell according to any one of claims 1 to 8.

10. The perovskite battery according to claim 9, characterized in that: The perovskite cell includes, from bottom to top, a transparent conductive oxide layer, an electron transport layer, a perovskite active layer, a hole transport layer and a metal electrode.

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