Preparation Method of Electron Transport Layer of Perovskite Solar Cell and Perovskite Solar Cell

Abstract

The present invention discloses a preparation method for an electron transport layer of a perovskite solar cell and a perovskite solar cell, belonging to the technical field of perovskite solar cells. The present invention prepares the electron transport layer through a first deposition and a second deposition. During the first deposition, a reducing agent is added to control the electron transport layer precursor solution in a state of low oxygen content, so that the initially deposited electron transport layer film can obtain a higher concentration of oxygen vacancies, which is beneficial to the extraction and migration of electrons, thereby achieving the purpose of improving the battery efficiency. During the second deposition, hydrogen peroxide is added to increase the oxygen content in the electron transport layer precursor solution, reducing the oxygen vacancy concentration in the subsequently deposited electron transport layer film, thereby improving the stability of the perovskite solar cell. By preparing the electron transport layer through two depositions, the stability of the perovskite solar cell is improved while its battery efficiency is also improved.

Description

Technical Field

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

[0002] Chemical bath deposition is a commonly used method for preparing SnO2 thin films of the electron transport layer. By controlling the deposition conditions, thin films with specific properties can be obtained. During the process of chemical bath deposition of SnO2 thin films, the oxygen content in the solution has an important influence on the properties of the deposited thin films. For example, a chemical bath solution with a low oxygen content can obtain an SnO2 thin film with a high oxygen vacancy concentration, which is beneficial for improving the electron extraction and migration of the electron transport layer.

[0003] In the existing technology, the properties of the thin film are usually regulated by changing the conditions of chemical bath deposition, such as temperature, time, the composition of the solution, etc. For example, volatile oxalic acid can be used to replace non-volatile mercaptoacetic acid to change the composition of the solution, and better stability of the SnO2 thin film can be obtained by cooperating with an interfacial modification of hydrogen peroxide. In addition, there are also some technologies that change the properties of the thin film by adding specific additives to the solution.

[0004] However, there are still some problems in the existing technology for improving the stability of perovskite solar cells. First, the existing technology often requires complex operations, which increases the production cost. Second, while improving the stability of the battery, the existing technology may sacrifice other performances of the battery, such as efficiency. Finally, the effect of the existing technology in improving the stability of the battery is limited, and further research and improvement are still needed. Summary of the Invention

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

[0006] To achieve the above purpose, the present invention provides a preparation method for an electron transport layer of a perovskite solar cell, including the following steps:

[0007] First deposition: placing a substrate in a first electron transport layer precursor solution for first deposition, wherein the first electron transport layer precursor solution contains a reducing agent;

[0008] Second deposition: placing the substrate that has completed the first deposition in a second electron transport layer precursor solution for second deposition to form an electron transport layer, wherein the second electron transport layer precursor solution contains hydrogen peroxide.

[0009] In some embodiments of the present invention, the reducing agent includes at least one of potassium sulfite and sodium sulfite.

[0010] In some embodiments of the present invention, the first electron transport layer precursor solution includes a solvent, and in the solvent, the addition amount of the reducing agent is (1-5) mg / 100 mL; and / or, the second electron transport layer precursor solution includes a solvent, and in the solvent, the addition amount of hydrogen peroxide is (0.5-1.5) mL / 100 mL.

[0011] In some embodiments of the present invention, the time of the first deposition is 3 h to 4 h; and / or, the time of the second deposition is 4 h to 5 h.

[0012] In some embodiments of the present invention, 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.

[0013] 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.

[0014] In some embodiments of the present invention, and / or, the first electron transport layer precursor solution includes at least one of SnO2 and TiO2;

[0015] and / or, the second electron transport layer precursor solution includes at least one of SnO2 and TiO2.

[0016] In some embodiments of the present invention, after the first deposition is completed, hydrogen peroxide is added to the first electron transport layer precursor solution to obtain the second electron transport layer precursor solution;

[0017] The present invention also provides a perovskite solar cell prepared by the preparation method of the perovskite solar cell as described above.

[0018] In some embodiments of the present invention, the perovskite solar cell sequentially includes a transparent conductive oxide layer, the electron transport layer, a perovskite active layer, a hole transport layer, and a metal electrode from bottom to top.

[0019] The beneficial effects that the present invention can achieve:

[0020] When preparing the electron transport layer in the present invention, two depositions are carried out. 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 state of low oxygen content, so that the initially deposited electron transport layer film can obtain a higher concentration of oxygen vacancies, which is beneficial to the extraction and migration of electrons, thereby achieving the purpose of improving the battery efficiency. During the second deposition, hydrogen peroxide is added to the electron transport layer precursor solution, which increases the oxygen content in the electron transport layer precursor solution, reduces the oxygen vacancy concentration in the subsequently deposited electron transport layer film, and thus improves the stability of the perovskite battery. Through the two depositions, while improving the stability of the perovskite battery, its battery efficiency is also improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0022] Figure 1 It is a current density - voltage (V) curve graph of the perovskite battery in Embodiment 1 of the present invention.

[0023] Figure 2 It is a current density - voltage (V) curve graph of the perovskite batteries in Comparative Example 2 and Embodiment 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] 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.

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0026] In the present invention, descriptions such as "first", "second", etc. are for descriptive purposes only, and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second" may explicitly or implicitly include at least one such feature. Additionally, the technical solutions between various embodiments may be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0027] The present invention provides a method for preparing an electron transport layer of a perovskite solar cell, comprising the following steps:

[0028] First deposition: placing a substrate in a first electron transport layer precursor solution for first deposition, wherein the first electron transport layer precursor solution contains a reducing agent;

[0029] Second deposition: placing the substrate that has completed the first deposition in a second electron transport layer precursor solution for second deposition to form an electron transport layer, wherein the second electron transport layer precursor solution contains hydrogen peroxide.

[0030] The present invention improves the method for preparing the electron transport layer of a perovskite solar cell. 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 to control the electron transport layer precursor solution in a state of low oxygen content, so that the initially deposited electron transport layer film can obtain a higher concentration of oxygen vacancies, which is beneficial to the extraction and migration of electrons, thereby achieving the purpose of improving the cell 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, reducing the oxygen vacancy concentration in the subsequently deposited electron transport layer film, thereby improving the stability of the perovskite solar cell. By preparing the electron transport layer through two depositions, the stability of the perovskite solar cell is improved while its cell efficiency is also improved.

[0031] In the present invention, the reducing agent has reducibility, which can reduce the oxygen content in the electron transport layer precursor solution, prompting 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 the cell efficiency.

[0032] In some embodiments, the reducing agent includes potassium sulfite and sodium sulfite. Reducing agents of the above types have good reducing properties, which are beneficial to reducing the oxygen content in the electron transport layer precursor solution, promoting the deposition of the electron transport layer film to obtain a high concentration of oxygen vacancies, thereby facilitating the extraction and migration of electrons, achieving the purpose of improving the 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.

[0033] 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 subsequently deposited electron transport layer film, and thus improve the stability of the perovskite battery.

[0034] In some embodiments, the first electron transport layer precursor solution includes a solvent. In the solvent, the addition amount of the reducing agent is (1 - 5) mg / 100 mL, which can 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 addition amount of the reducing agent, the stability of the battery is further improved to meet the actual application requirements.

[0035] In some embodiments, the second electron transport layer precursor solution includes a solvent. In the solvent, the addition amount of hydrogen peroxide is (0.5 - 1.5) ml / 100 mL, which can be 0.5 mg / 100 mL, 1 mg / 100 mL, 1.5 mg / 100 mL, etc. By adjusting the addition amount of hydrogen peroxide, the stability of the battery is further improved to meet the actual application requirements.

[0036] In some embodiments, the time for the first deposition is 3 h to 4 h.

[0037] In some embodiments, the temperature for the first deposition is 85 °C to 95 °C.

[0038] In some embodiments, the time for the second deposition is 1 h to 2 h.

[0039] In some embodiments, the temperature for the second deposition is 85 °C to 95 °C.

[0040] In some embodiments, after the second deposition is completed, annealing treatment is also performed. Completing the annealing treatment after the last deposition is beneficial to the fusion of the electron transport layer films formed by the first deposition and the second deposition.

[0041] In some embodiments, the annealing temperature is 160 °C to 170 °C.

[0042] In some embodiments, the annealing time is 0.5 h to 1 h.

[0043] 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 at least one of SnO2 and TiO2.

[0044] In some embodiments, the first electron transport layer precursor solution includes at least one of SnO2 and TiO2, and the second electron transport layer precursor solution includes at least one of SnO2 and TiO2.

[0045] In some embodiments, both the first electron transport layer precursor solution and the second electron transport layer precursor solution contain a solvent, which is used to disperse the electron transport layer material, 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.

[0046] 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 the first electron transport layer precursor solution, and hydrogen peroxide is added to the electron transport layer solution matrix to obtain the second electron transport layer precursor solution.

[0047] In the present invention, the electron transport layer solution 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 it easy for them to fuse to obtain the electron transport layer.

[0048] 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 is divided into two parts. A reducing agent is added to one part to form the first electron transport layer precursor solution, and hydrogen peroxide is added to the other part to form the second electron transport layer precursor solution. Then, the first deposition is performed on the substrate in the above first electron transport layer precursor solution. After the first deposition is completed, the substrate is placed in the above second electron transport layer solution for the second deposition. The matrices of the first electron transport layer precursor solution and the second electron transport layer precursor solution in this embodiment are the same, which can reduce the difference between the electron transport layer films obtained by the first deposition and the second deposition, making it easy for them to fuse to obtain the electron transport layer, and mass production can be achieved.

[0049] Exemplarily, the electron transport layer material can also be dispersed in a solvent to prepare two identical electron transport layer solution matrices. 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. Then, the first deposition is performed on the substrate 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 the 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 it easy for them to fuse to obtain the electron transport layer, and mass production can be achieved.

[0050] Exemplarily, a first electron transport layer precursor solution containing a reducing agent can also be prepared first. After the first deposition is completed, hydrogen peroxide is continuously added to the first electron transport layer precursor solution to obtain a second electron transport layer precursor solution, and the second deposition is completed using this second electron transport layer precursor solution. In this embodiment, the compositions of the first electron transport layer precursor solution and the second electron transport layer precursor solution are similar, which is easy to reduce the difference between the electron transport layer films obtained by the first deposition and the second deposition, making it easy for them to fuse to obtain the electron transport layer, and the waste of raw materials can be reduced and the experimental steps can be reduced.

[0051] In some embodiments, the method for preparing the electron transport layer of the perovskite battery of the present invention includes the following steps:

[0052] First deposition: The substrate is placed in the first electron transport layer precursor solution for the first deposition, and the first electron transport layer precursor solution contains a reducing agent;

[0053] Second deposition: Hydrogen peroxide is added to the first electron transport layer precursor solution after the first deposition is completed to obtain a second electron transport layer precursor solution, and the substrate after the first deposition is placed in this second electron transport layer precursor solution for the second deposition to form an electron transport layer.

[0054] In some embodiments, the substrate includes a glass substrate and a transparent conductive oxide layer formed on the surface of the glass substrate, and the electron transport layer is deposited on the surface of the transparent conductive oxide layer.

[0055] In the present invention, the material for preparing the transparent conductive oxide layer can be selected from common materials in the art. In some embodiments, it includes at least one of indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), and fluorine-doped tin oxide (FTO).

[0056] In some embodiments, the substrate further includes an interface modification layer commonly used in the art, such as a passivation layer, etc., which is disposed between the transparent conductive oxide layer and the electron transport layer and is used to modify the electron transport layer. Therefore, in this embodiment, it is necessary to deposit an electron transport layer on the surface of the interface modification layer of the substrate.

[0057] The present invention further provides a perovskite solar cell and a preparation method thereof. The preparation method of the perovskite solar cell includes the steps in the preparation method of the electron transport layer described above. The prepared perovskite solar cell contains the electron transport layer described above and at least has all the beneficial effects of the above electron transport layer.

[0058] The preparation of other functional layers is also included in the perovskite solar cell of the present invention, 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 elaborated here.

[0059] In some embodiments, the perovskite solar cell includes a glass substrate, a transparent oxide layer, the electron transport layer of the present invention, a perovskite active layer, a hole transport layer, and a metal electrode in sequence from bottom to top.

[0060] In some embodiments, an interface modification layer, such as a passivation layer, can also be designed between the perovskite active layer and the hole transport layer, which serves to reduce the 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 solar cell.

[0061] The technical solution of the present invention will be further described in detail below with reference to 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.

[0062] Example 1

[0063] The preparation of the perovskite solar cell in Example 1 is as follows:

[0064] Prepare the substrate

[0065] The FTO glass substrate protected by a high-temperature resistant tape is ultrasonically cleaned in an anionic surfactant solution, deionized water, ethanol, and isopropanol for 15 minutes respectively. After the cleaning is completed, it is dried with a nitrogen stream and reserved for use.

[0066] Deposit the electron transport layer

[0067] First deposition: Add 2.5 g of urea, 550 mg of SnCl2·2H2O, 200 mL of ultrapure water, 2.5 mL of HCl, 50 μL of thioglycolic acid (TGA), and 10 mg of K2SO3 into a 500 mL beaker, and stir evenly to obtain the precursor solution of the first electron transport layer. Place the FTO glass vertically in the precursor solution of the first electron transport layer, then place the beaker in a water bath at 90 °C and start timing the reaction. The reaction deposits for 3.5 h.

[0068] Second deposition: When the first deposition reaction reaches 3.5 h, add 3 mL of H2O2 into the precursor solution of the first electron transport layer to form the precursor solution of the second electron transport layer. Let the FTO glass continue to react until 5 h, then take out the FTO glass, tear off the high-temperature resistant tape on the FTO glass, and ultrasonically clean it with deionized water and isopropanol for 5 min respectively. After drying with a nitrogen stream, place it on a hot stage and anneal it at 170 °C for 1 h to form the electron transport layer.

[0069] Depositing the perovskite layer

[0070] Accurately weigh 1.383 g of PbI2, dissolve it in 2 mL of anhydrous DMF / DMSO mixed solvent (v:v = 9:1), and stir at 60 °C for 2 h to prepare the PbI2 solution; accurately weigh 180 mg of the mixture of FAI, 18 mg of MABr, and 20 mg of MACl, dissolve it in 2 mL of anhydrous isopropanol, and stir at room temperature until transparent to prepare the FAI / MABr / MACl solution.

[0071] Deposit the perovskite active layer by a two-step method: Place the FTO glass deposited with the electron transport layer in an ultraviolet ozone treatment machine and treat it with ozone for 20 min. In a glove box with a nitrogen atmosphere, first spin-coat 80 μL of the PbI2 solution statically on the substrate of the electron transport layer, with specific parameters of 1500 rpm for 30 s, then anneal it at 70 °C for 1 min to obtain the PbI2 thin film. After the PbI2 thin film is completely cooled, spin-coat 150 μL of the FAI / MABr / MACl solution statically on the PbI2 thin film at a speed of 2100 rpm for 30 s to obtain the perovskite thin film. Anneal the formed perovskite thin film in a glove box with low humidity (RH < 30%) at 170 °C for 10 min to prepare the perovskite active layer.

[0072] Depositing the passivation layer

[0073] Accurately weigh 15 mg of 2-phenethylamine hydroiodide (PEAI), dissolve it in 3 mL of anhydrous isopropanol, and mix the solution by shaking with an oscillator. In a glove box under a nitrogen atmosphere, statically spin-coat 100 μL of the solution onto the perovskite active layer with the specific spin-coating parameters of 5000 rpm for 30 s. After the spin-coating process, no further annealing treatment is required, and the deposition of the hole transport layer can be carried out directly.

[0074] Deposition of the hole transport layer

[0075] Accurately weigh 90 mg of Spiro-OMeTAD, add 44 μL of the stock solution of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) (260 mg of Li-TFSI dissolved in 1 mL of anhydrous acetonitrile), 37 μL of 4-tert-butylpyridine (tBP), and 1 mL of anhydrous chlorobenzene, and ultrasonically treat for 5 min to mix the solution evenly. In a glove box under a nitrogen atmosphere, dynamically spin-coat 60 μL of the solution onto the passivation layer film with the specific spin-coating parameters of 2000 rpm for 30 s, without further annealing treatment.

[0076] Deposition of the metal back electrode

[0077] After trimming the edges of the FTO substrate with the deposited hole transport layer, place it in a vacuum coater and evaporate a 100 nm Ag electrode to finally obtain a complete perovskite solar cell device.

[0078] Example 2

[0079] The perovskite solar cell in Example 2 was prepared with reference to the preparation method of Example 1. The difference is that in Example 2, the perovskite active layer was prepared by a one-step method, specifically as follows:

[0080] Accurately weigh a powder mixture of 19.5 mg of CsI, 15.9 mg of RbI, 8.4 mg of MABr, 219.5 mg of FAI, 656.9 mg of PbI2, and 27.5 mg of PbBr2, dissolve it in 1 mL of anhydrous DMF / DMSO mixed solvent (v:v = 4:1), and shake it with a vortex shaker for 2 h to completely dissolve it to obtain a perovskite precursor solution. The component composition of this precursor solution is Rb 0.05 Cs 0.05 MA 0.05 FA 0.85 Pb(I 0.95 Br 0.05 )3, and the concentration is 1.5 M.

[0081] The one-step method is selected to prepare the perovskite thin film, and anhydrous chlorobenzene is used as the anti-solvent. The FTO glass deposited with the electron transport layer is placed in an ultraviolet ozone treatment machine for ozone treatment for 20 min. In the glove box under a nitrogen atmosphere, 70 μL of the perovskite precursor solution is spin-coated on the electron transport layer substrate. The spin-coating is divided into two processes, and the specific parameters are 1000 rpm, 10 s and 3000 rpm, 30 s. And 150 μL of anhydrous chlorobenzene is quickly dropped when the second process reaches 15 s. After the spin-coating is completed, the thin film is annealed at 100 °C for 10 min to form the perovskite active layer.

[0082] Example 3

[0083] Example 3 prepared the perovskite solar cell with reference to Example 1. However, the difference is that when preparing the electron transport layer, the amounts of K2SO3 and H2O2 in the chemical bath solution in Example 3 are different. The amounts of K2SO3 and H2O2 in the chemical bath solution in Example 3 are 2 mg and 1 mL respectively.

[0084] Example 4

[0085] Example 4 prepared the perovskite solar cell with reference to Example 1. However, the difference is that when preparing the electron transport layer, the amounts of K2SO3 and H2O2 in the chemical bath solution in Example 3 are different: The amounts of K2SO3 and H2O2 in the chemical bath solution in Example 4 are 10 mg and 3 mL respectively.

[0086] Example 5

[0087] Example 5 prepared the perovskite solar cell with reference to Example 2. However, the difference is that when preparing the electron transport layer, the amounts of K2SO3 and H2O2 in the chemical bath solution in Example 5 are different: The amounts of K2SO3 and H2O2 in the chemical bath solution in Example 5 are 2 mg and 1 mL respectively.

[0088] Example 6

[0089] Example 6 prepared the perovskite solar cell with reference to Example 2. However, the difference is that when preparing the electron transport layer, the amounts of K2SO3 and H2O2 in the chemical bath solution in Example 6 are different: The amounts of K2SO3 and H2O2 in the chemical bath solution in Example 6 are 10 mg and 3 mL respectively.

[0090] Comparative Example 1

[0091] Comparative Example 1 prepared the perovskite solar cell with reference to the preparation method of Example 1. The difference is that the preparation steps of its electron transport layer are as follows:

[0092] Add 2.5 g of urea, 550 mg of SnCl2·2H2O, 200 mL of ultrapure water, 2.5 mL of HCl, and 50 μL of TGA into a 500 mL beaker, and stir evenly to obtain the precursor solution for the electron transport layer.

[0093] After placing the FTO glass vertically in the precursor solution for the electron transport layer, place the beaker in a water bath at 90 °C and start timing. When the reaction proceeds for 5 h, take out the FTO glass, tear off the high-temperature resistant tape, then ultrasonically clean it with deionized water and isopropanol for 5 min respectively, dry it with a nitrogen stream, and place it on a hot stage for annealing at 170 °C for 1 h to form the electron transport layer.

[0094] Comparative Example 2

[0095] Prepare the perovskite solar cell with reference to the preparation method of Example 1 in Comparative Example 2. The difference is that the preparation steps of its electron transport layer are as follows:

[0096] Add 2.5 g of urea, 550 mg of SnCl2·2H2O, 200 mL of ultrapure water, 2.5 mL of HCl, and 50 μL of TGA into a 500 mL beaker, and stir evenly to obtain the precursor solution for the electron transport layer.

[0097] After placing the FTO glass vertically in the precursor solution for the electron transport layer, place the beaker in a water bath at 90 °C and start timing. When the reaction proceeds for 5 h, take out the FTO glass, tear off the high-temperature resistant tape, then ultrasonically clean it with deionized water and isopropanol for 5 min respectively, dry it with a nitrogen stream, and place it on a hot stage for annealing at 170 °C for 1 h to form the electron transport layer;

[0098] Performance Test

[0099] 1. Compare the storage stability of the devices in Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and the devices in Example 3 to Example 6 under the condition of relative humidity of 30% - 40%. The changes in device efficiency from 0 to 7 days are summarized in Table 1.

[0100] 2. Measure the Voc open-circuit voltage (V), Jsc short-circuit current density (mA / cm 2 ), FF fill factor (%), and PCE power conversion efficiency (%) of the perovskite solar cell devices obtained in Example 1 to Example 6 and Comparative Example 1 to 2. The results are shown in Table 2. In addition, the data comparison between Example 1 and Comparative Example 1 can also be seen in Figure 1 , and the data comparison between Example 2 and Comparative Example 2 can also be seen in Figure 2 .

[0101] Table 1 Efficiency of Examples and Comparative Examples at Different Storage Times

[0102]

[0103] As can be seen from Table 1, the devices of Example 1 still maintained more than 95% of the initial efficiency after being stored for 7 days. The efficiency of the devices of Comparative Example 1 decreased to less than 80% of the initial efficiency. The devices of Example 2 still maintained more than 95% of the initial efficiency after being stored for 7 days. The efficiency of the devices of Comparative Example 2 decreased to about 80% of the initial efficiency. It can be seen that depositing the electron transport layer by adding a reducing agent and hydrogen peroxide respectively is beneficial to improving the stability of the perovskite battery. Similarly, the perovskite batteries obtained by depositing the electron transport layer by adding a reducing agent and hydrogen peroxide in Examples 3 to 6 also obtained good stability.

[0104] Table 2 Performance comparison of perovskite batteries obtained in Examples and Comparative Examples

[0105]

[0106] Combined with Figure 1 、 Figure 2 and Table 2, it can be known that the devices prepared in Examples 1 to 6 all obtained good photoelectric conversion efficiencies. The photoelectric conversion efficiencies of the perovskite batteries prepared in Comparative Example 1, which did not add a reducing agent and hydrogen peroxide respectively to prepare the electron transport layer relative to Example 1, and Comparative Example 2, which did not add a reducing agent and hydrogen peroxide respectively to prepare the electron transport layer relative to Example 2, decreased relative to Example 1 and Example 2 respectively.

[0107] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be included in the patent protection scope of the present invention by the same token.

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; The reducing agent includes at least one of potassium sulfite and sodium sulfite.

2. 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 to 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.

3. 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.

4. 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.

5. 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.

6. 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 at least one of SnO2 and TiO2; And / or, the second electron transport layer precursor solution includes at least one of SnO2 and TiO2.

7. The method for preparing the electron transport layer of a perovskite battery according to any one of claims 1 to 6, 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.

8. 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 7.

9. The perovskite cell according to claim 8, 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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