Perovskite precursor solution, manufacturing method for perovskite layer, perovskite stacked solar cell and manufacturing method therefor

Abstract

A perovskite precursor solution, a manufacturing method for a perovskite layer, a perovskite stacked solar cell and a manufacturing method therefor. The perovskite precursor solution comprises a perovskite material and a mixed solvent, the viscosity of the mixed solvent being 2 mPa·s-3.5 mPa·s. The mixed solvent comprises a first solvent, the volume of the first solvent accounting for 10%-40% of that of the mixed solvent, and the boiling point of the first solvent being 80°C-130°C.

Description

Perovskite precursor solution, preparation method of perovskite layer, and perovskite tandem solar cell and preparation method thereof

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on September 25, 2023, with application number 202311250096.2 and invention name “Perovskite precursor solution, preparation method of perovskite layer and perovskite tandem solar cell and preparation method thereof”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the field of solar cells, and in particular to a perovskite precursor solution, a preparation method of a perovskite layer, a perovskite stacked solar cell and a preparation method thereof. Background Art

[0003] The solution method for preparing perovskite layers has the advantages of being simple and rapid, and is very beneficial for improving the production efficiency of perovskite silicon tandem solar cells. However, the solution method for preparing perovskite layers is generally used in perovskite solar cells with a planar structure. It is difficult to achieve a good conformal deposition effect on perovskite tandem solar cells with a pyramid surface, especially on large-area pyramid surfaces. Currently, the perovskite layer on perovskite tandem solar cells with a pyramid surface is usually prepared using a solution method combined with an evaporation method. This preparation method is relatively cumbersome and is not conducive to improving production efficiency.

[0004] Summary of the Invention

[0005] The embodiments of the present invention disclose a perovskite precursor solution, a method for preparing a perovskite layer, a perovskite tandem solar cell and a method for preparing the same. The perovskite precursor solution is coated on a pyramid velvet substrate, and a perovskite layer with excellent shape retention and crystallization effects can be prepared on the pyramid velvet substrate, thereby solving the problem of difficulty in achieving shape retention when preparing a perovskite layer on a pyramid velvet substrate using a solution method.

[0006] In order to achieve the above-mentioned objectives, in a first aspect, the present invention discloses a perovskite precursor solution, which comprises: a perovskite material and a mixed solvent, the viscosity of the mixed solvent is 2mPa·s~3.5mPa·s, the mixed solvent comprises a first solvent, the volume of the first solvent accounts for 10%~40% of the mixed solvent, and the boiling point of the first solvent is 80℃~130℃.

[0007] As an optional implementation, in an embodiment of the present invention, the mixed solvent further includes a second solvent, and the second solvent includes one or both of dimethyl sulfoxide and 1,8-diiodooctane.

[0008] As an optional embodiment, in an embodiment of the present invention, the second solvent is composed of the dimethyl sulfoxide and the 1,8-diiodooctane in a mass ratio of (0.4-0.8):1.

[0009] As an optional embodiment, in an embodiment of the present invention, the first solvent includes one or more of acetonitrile, ethanol, 2-methoxyethanol and isopropanol.

[0010] As an optional embodiment, in an embodiment of the present invention, the first solvent is composed of acetonitrile and 2-methoxyethanol in a volume ratio of (0.25-0.82):1.

[0011] As an optional implementation, in an embodiment of the present invention, the concentration of the perovskite precursor solution is 0.8 mol / mL to 2 mol / mL.

[0012] In a second aspect, the present application provides a method for preparing a perovskite layer, the method for preparing the perovskite layer comprising the following steps:

[0013] providing a substrate having a pyramid pile surface;

[0014] The perovskite precursor solution is coated on the substrate to form a perovskite wet film layer, and an airflow with a temperature of 80°C to 130°C and a wind pressure of 1MPa to 2MPa is blown toward the perovskite wet film layer, wherein the temperature of the airflow is not lower than the boiling point of the first solvent, to obtain the perovskite layer.

[0015] As an optional implementation, in an embodiment of the present invention, the thickness of the perovskite layer is 800 nm to 1500 nm.

[0016] As an optional implementation manner, in an embodiment of the present invention, the coating method of the perovskite precursor solution includes any one of slit coating, screen printing and doctor blade coating.

[0017] As an optional implementation, in an embodiment of the present invention, the coating speed of the perovskite precursor solution is 5 mm / s to 20 mm / s.

[0018] As an optional implementation manner, in an embodiment of the present invention, after the perovskite precursor solution is coated, the thickness of the perovskite wet film layer formed is 5 μm to 10 μm.

[0019] As an optional implementation, in an embodiment of the present invention, the gas flow is nitrogen or an inert gas.

[0020] As an optional implementation, in an embodiment of the present invention, when the slit coating method is adopted, the slit size is controlled to be 70 μm to 110 μm.

[0021] In a third aspect, the present application provides a perovskite tandem solar cell, the perovskite tandem solar cell comprising:

[0022] The perovskite tandem solar cell includes a silicon base cell and a first transparent conductive layer, a hole transport layer, a perovskite layer, an electron transport layer and a second transparent conductive layer stacked in sequence on the silicon base cell. The perovskite layer is prepared by the preparation method of the perovskite layer described in the second aspect. The perovskite tandem solar cell also includes a positive electrode and a negative electrode. The positive electrode forms an ohmic contact with the electron transport layer, and the negative electrode forms an ohmic contact with the silicon base cell.

[0023] As an optional embodiment, in an embodiment of the present invention, a hole modification layer is further provided between the perovskite layer and the hole transport layer; and / or, a passivation layer is further provided between the perovskite layer and the electron transport layer; and / or, a buffer layer is further provided on the electron transport layer facing away from the silicon substrate battery, and an anti-reflection layer is further provided on the side of the second transparent conductive layer facing away from the silicon substrate battery.

[0024] As an optional implementation, in an embodiment of the present invention, the thickness of the hole transport layer is 15 nm to 25 nm.

[0025] As an optional implementation, in an embodiment of the present invention, the thickness of the electron transport layer is 10 nm to 20 nm.

[0026] As an optional implementation, in an embodiment of the present invention, the thickness of the hole modification layer is 1 nm to 5 nm.

[0027] As an optional implementation manner, in an embodiment of the present invention, the thickness of the passivation layer is 1 nm to 3 nm.

[0028] As an optional implementation, in an embodiment of the present invention, the thickness of the buffer layer is 10 nm to 20 nm.

[0029] As an optional implementation manner, in an embodiment of the present invention, the thickness of the anti-reflection layer is 90 nm to 120 nm.

[0030] In a fourth aspect, the present application provides a method for preparing a perovskite tandem solar cell, the perovskite tandem solar cell comprising the following steps:

[0031] Provide silicon substrate cells;

[0032] Prepare a first transparent conductive layer on the front side of the silicon substrate battery;

[0033] preparing a hole transport layer on the first transparent conductive layer;

[0034] A perovskite layer is prepared on the hole transport layer, and the perovskite layer is prepared by the preparation method of the perovskite layer described in the second aspect.

[0035] preparing an electron transport layer on the perovskite layer;

[0036] forming a second transparent conductive layer on the electron transport layer;

[0037] A positive electrode is prepared on the second transparent conductive layer, and a negative electrode is prepared on the back of the silicon substrate cell to obtain the above-mentioned perovskite stacked solar cell.

[0038] As an optional embodiment, in an embodiment of the present invention, a hole modification layer is further prepared between the hole transport layer and the perovskite layer, a passivation layer is further prepared between the perovskite layer and the electron transport layer, and a buffer layer is further prepared on the side of the electron transport layer facing away from the silicon substrate battery.

[0039] As an optional implementation, in an embodiment of the present invention, the hole transport layer, the hole modification layer, the passivation layer, the electron transport layer and / or the buffer layer are prepared by slit coating.

[0040] The above-mentioned functional layers such as the hole transport layer, hole modification layer, passivation layer, electron transport layer and buffer layer can all be prepared by slit coating.

[0041] As an optional embodiment, in an embodiment of the present invention, the preparation method of the hole transport layer is as follows: dissolving an aqueous solution of nickel oxide nanocrystals in a volatile solvent to obtain a nickel oxide nanocrystal solution, then coating the nickel oxide nanocrystal solution to form a hole transport layer wet film, and then blowing an air flow with a temperature of 60°C and a wind pressure of 1 MPa toward the surface of the hole transport layer wet film to obtain a hole transport layer, wherein the volatile solvent is one or more of ethanol, acetonitrile and isopropanol.

[0042] As an optional embodiment, in an embodiment of the present invention, the preparation method of the hole transport layer is as follows: dissolving an aqueous solution of nickel oxide nanocrystals in a volatile solvent to obtain a nickel oxide nanocrystal solution, then coating the nickel oxide nanocrystal solution to form a hole transport layer wet film, and then blowing an air flow with a temperature of 50°C to 70°C and a wind pressure of 0.8MPa to 1.2MPa toward the surface of the hole transport layer wet film to obtain a hole transport layer, wherein the volatile solvent is one or more of ethanol, acetonitrile and isopropanol.

[0043] As an optional embodiment, in an embodiment of the present invention, the preparation method of the electron transport layer is as follows: C 60 Dissolved in chlorobenzene, added with ethanol, to obtain C 60 solution, followed by coating C60 The solution is prepared to form an electron transport layer wet film, and then an air flow with a temperature of 40° C. to 60° C. and a wind pressure of 0.6 MPa to 1 MPa is blown toward the surface of the electron transport layer wet film to obtain the electron transport layer.

[0044] As an optional embodiment, in an embodiment of the present invention, the preparation method of the hole modification layer is as follows: 2PACz is dissolved in ethanol to obtain a 2PACz solution, and then the 2PACz solution is coated to form a hole modification layer wet film, and then an air flow with a temperature of 40°C to 50°C and a wind pressure of 0.2MPa to 0.5MPa is blown toward the surface of the hole modification layer wet film to obtain the hole modification layer.

[0045] As an optional embodiment, in an embodiment of the present invention, a passivation layer is further prepared between the perovskite layer and the electron transport layer, and the preparation method of the passivation layer is as follows: 2-thiopheneethylamine bromide is dissolved in isopropanol to obtain a 2-thiopheneethylamine bromide solution, and then the 2-thiopheneethylamine bromide solution is applied to form a passivation layer wet film, and then an air flow with a temperature of 50°C to 60°C and a wind pressure of 0.4MPa to 0.6MPa is blown toward the surface of the passivation layer wet film to obtain a passivation layer.

[0046] As an optional embodiment, in an embodiment of the present invention, the preparation method of the buffer layer is as follows: dissolving a tin dioxide hydrocolloid solution in a mixed solvent of water and ethanol to obtain a tin dioxide solution, then coating the tin dioxide solution to form a buffer layer wet film, and then blowing an airflow with a temperature of 50°C to 70°C and a wind pressure of 0.5MPa to 1MPa toward the surface of the buffer layer wet film to obtain a buffer layer.

[0047] As an optional embodiment, in an embodiment of the present invention, during the preparation of the hole transport layer, the concentration of the nickel oxide nanocrystalline solution is 10 mg / mL to 15 mg / mL, the slit spacing is 50 μm to 80 μm, the coating speed is 7 mm / s to 14 mm / s, and the thickness of the wet film of the hole transport layer is 2 μm to 5 μm.

[0048] As an optional embodiment, in an embodiment of the present invention, during the preparation of the electron transport layer, the C 60 The concentration of the solution is 0.8 mg / ml to 2.0 mg / ml, the slit spacing is 30 μm to 70 μm, the coating speed is 7 mm / s to 14 mm / s, and the thickness of the electron transport layer wet film is 4 μm to 7 μm.

[0049] As an optional embodiment, in an embodiment of the present invention, during the preparation of the hole modification layer, the concentration of the 2PACz solution is 0.1 mg / ml to 0.5 mg / ml, the slit spacing is 15 μm to 25 μm, the coating speed is 10 mm / s to 20 mm / s, and the thickness of the passivation layer wet film is 1 μm to 3 μm.

[0050] As an optional embodiment, in an embodiment of the present invention, during the preparation of the passivation layer, the concentration of the 2-thiopheneethylamine bromide salt solution is 0.8 mg / ml to 2.0 mg / ml, the slit spacing is 20 μm to 40 μm, the coating speed is 15 mm / s to 25 mm / s, and the thickness of the passivation layer wet film is 1 μm to 4 μm.

[0051] As an optional embodiment, in an embodiment of the present invention, during the preparation of the buffer layer, the concentration of the tin dioxide hydrocolloid solution is 1.5% to 5%, the slit spacing is 50 μm to 80 μm, the coating speed is 7 mm / s to 14 mm / s, and the thickness of the passivation layer wet film is 1 μm to 5 μm.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] An embodiment of the present invention provides a perovskite precursor solution, wherein the viscosity of the mixed solvent used in the perovskite precursor solution is 2 mPa·s to 3.5 mPa·s, and because the mixed solvent contains a specific proportion of a first solvent with a low boiling point and high volatility, the perovskite precursor solution is applied to a substrate having a pyramid velvet surface. The perovskite precursor solution of a specific viscosity prepared by adding the specific proportion of the first solvent has relatively low fluidity, which can achieve uniform coating on the pyramid velvet substrate to form a perovskite layer with good thickness uniformity, and can stably adhere to the surface of the pyramid velvet substrate, especially when facing a velvet substrate with a pyramid height greater than 2 μm, and can stably cover the pyramid tip without easily depositing to the bottom. Moreover, due to the addition of the above-mentioned specific proportion of the first solvent, the mixed solvent in the perovskite precursor solution can evaporate rapidly, promoting the rapid crystallization and growth of the perovskite material in the perovskite precursor in situ, forming a perovskite layer with good conformal coverage. The mixed solvent of the perovskite precursor solution can evaporate quickly and rapidly crystallize and grow in situ without the need for annealing treatment, thereby obtaining a perovskite layer with no obvious solvent residue and excellent crystal growth effect.

[0054] In summary, the use of the above-mentioned perovskite precursor solution can prepare a perovskite layer with excellent shape retention and crystallization effects on a pyramid velvet substrate, solving the problem that it is difficult to achieve shape retention when preparing a perovskite layer on a pyramid velvet substrate using a solution method. At the same time, a perovskite layer with excellent crystallization effect can be obtained without further annealing process treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. 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 these drawings without paying any creative work.

[0056] FIG1 is a schematic structural diagram of a perovskite tandem solar cell disclosed in an embodiment of the present invention;

[0057] FIG2 is a schematic structural diagram of another perovskite tandem solar cell disclosed in an embodiment of the present invention;

[0058] FIG3 is a SEM scanning electron microscope image of the perovskite layer according to Example 1 of the present invention.

[0059] Icons: 1. Heterojunction bottom cell; 2. First transparent conductive layer; 3. Hole transport layer; 31. Hole modification layer; 4. Perovskite layer; 41. Passivation layer; 5. Electron transport layer; 51. Buffer layer; 6. Second transparent conductive layer; 71. Positive electrode; 72. Negative electrode; 8. Anti-reflection layer. DETAILED DESCRIPTION

[0060] 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0061] The solution method for preparing a perovskite layer refers to coating a perovskite precursor solution to form a wet film, and then annealing the film to obtain a perovskite layer. At present, the solution method for preparing a perovskite layer is generally only applicable to flat substrates or small-area pyramid velvet substrates (pyramid height is less than 2μm), and is not suitable for large-area pyramid velvet substrates. This is because when the perovskite precursor solution is coated on the pyramid velvet substrate, the perovskite precursor solution is easily deposited to the bottom of the pyramid velvet substrate, and it is difficult to cover the top of the pyramid, which can easily lead to a short circuit. The pyramid velvet area of ​​commercial silicon-based batteries is large, and the height is generally greater than 2μm. The perovskite precursor solution is more likely to be deposited at the bottom of the pyramid velvet, making it difficult to achieve conformal growth on a large-area pyramid velvet substrate. At present, when preparing perovskite layers on large-area velvet substrates, a vacuum evaporation method is generally used to first evaporate a layer of lead iodide, and then a cationic solution is coated through a solution method to react the cationic solution with the lead iodide layer to obtain the perovskite layer. Although this method can better achieve shape preservation when preparing perovskite layers, it requires two steps of growth, which is relatively cumbersome and not conducive to improving production efficiency.

[0062] To this end, the present application provides a perovskite precursor solution and a preparation method thereof, a perovskite layer stacked solar cell and a preparation method thereof. By adopting a specific perovskite precursor solution as a solution for preparing the perovskite layer, the present application solves the problem that it is difficult to achieve conformal growth when preparing the perovskite layer by a solution method on a pyramid velvet substrate. At the same time, the present application has the advantages of a simple preparation process, easy operation, and suitability for industrial production.

[0063] In addition, the perovskite precursor solution can be used to prepare a perovskite layer with good shape retention on a large or small area pyramid velvet substrate, and has the advantage of a wide range of adaptability.

[0064] The technical solution of the present invention will be further described below in conjunction with embodiments and drawings.

[0065] In a first aspect, embodiments of the present application provide a perovskite precursor solution.

[0066] The perovskite precursor solution includes a perovskite material and a mixed solvent. The viscosity of the mixed solvent is 2mPa·s to 3.5mPa·s. The mixed solvent includes a first solvent. The volume of the first solvent accounts for 10% to 40% of the mixed solvent. The boiling point of the first solvent is 80°C to 130°C.

[0067] The viscosity of the mixed solvent is 2 mPa·s to 3.5 mPa·s. Because the mixed solvent contains a specific proportion of a first solvent with a low boiling point and high volatility, the perovskite precursor solution is applied to a substrate having a pyramid velvet surface. The perovskite precursor solution with a specific viscosity and a specific proportion of the first solvent has relatively low fluidity. This allows for uniform coating on the pyramid velvet substrate, forming a perovskite layer 4 with excellent thickness uniformity. Furthermore, the solution can stably adhere to the surface of the pyramid velvet substrate, especially when facing a velvet substrate with a pyramid height greater than 2 μm, and can stably cover the pyramid tip without easily depositing on the bottom. Furthermore, due to the addition of the specific proportion of the first solvent, the mixed solvent in the perovskite precursor solution evaporates rapidly, promoting the rapid in-situ crystallization and growth of the perovskite material in the perovskite precursor, forming a perovskite layer 4 with excellent conformal coverage. The mixed solvent of the perovskite precursor solution can evaporate quickly and rapidly crystallize and grow in situ without the need for annealing, thereby obtaining a perovskite layer 4 with no obvious solvent residue and excellent crystal growth effect.

[0068] In summary, the above-mentioned perovskite precursor solution can be used to prepare a perovskite layer 4 with excellent shape retention and crystallization effects on a pyramid velvet substrate, thereby solving the problem that it is difficult to achieve shape retention when preparing a perovskite layer 4 on a pyramid velvet substrate using a solution method. At the same time, a perovskite layer 4 with excellent crystallization effect can be obtained without further annealing process treatment.

[0069] For example, the viscosity of the mixed solvent may be 2 mPa·s, 2.3 mPa·s, 2.6 mPa·s, 2.9 mPa·s, 3.2 mPa·s, 3.5 mPa·s, etc. The boiling point of the first solvent may be 80° C., 90° C., 100° C., 110° C., 120° C., 130° C., etc.

[0070] Preferably, the second solvent is one or a combination of dimethyl sulfoxide and 1,8-diiodooctane.

[0071] By specifically selecting dimethyl sulfoxide and 1,8-diiodooctane, which have higher viscosities, as the second solvent, it is beneficial to quickly increase the viscosity of the mixed solvent. Adjusting the viscosity of the mixed solvent to the above-mentioned specific range is beneficial to improving the construction performance of the perovskite precursor solution, while also improving the adhesion stability of the perovskite precursor solution on the surface of the pyramid velvet substrate, so that after coating, the perovskite precursor solution quickly forms a conformal perovskite wet film layer on the pyramid velvet substrate. At the same time, the iodide ions in 1,8-diiodooctane participate in the formation of perovskite crystals, which is beneficial to promote the in-situ crystallization of the perovskite material, reduce the fluidity of the perovskite wet film layer, and further improve the conformal coverage effect of the perovskite layer 4.

[0072] The above-mentioned perovskite material can be selected from a trication system material. The perovskite material can be selected from any three of methylamine iodide (MAI), methylamido iodide (FAI), methylamine bromide (MABr), methylamido bromide (FABr), methylamine chloride (MACl), cesium iodide (CsI) and cesium bromide (CsBr) to form a trication system material. The specific selection of the perovskite material component does not affect the preparation of the conformal covered perovskite layer 4 on the pyramid velvet substrate using the above-mentioned perovskite precursor solution. The embodiment of the present application does not limit the specific selection of the perovskite component.

[0073] More preferably, the second solvent is composed of dimethyl sulfoxide and 1,8-diiodooctane in a mass ratio of (0.4-0.8):1.

[0074] Dimethyl sulfoxide and 1,8-diiodooctane are mixed in the above proportions, and the viscosity of the mixed solution is relatively high, which is conducive to the stable adhesion of the perovskite precursor solution to the surface of the pyramid velvet substrate. At the same time, 1,8-diiodooctane participates in the crystallization reaction of the perovskite layer 4, which is conducive to promoting the formation of perovskite crystals, improving the crystallization effect of the perovskite layer 4, reducing the crystallization defects of the perovskite layer 4, and improving the stability of the perovskite layer 4.

[0075] In some embodiments, the first solvent includes one or more of acetonitrile, ethanol, 2-methoxyethanol, and isopropanol.

[0076] Acetonitrile, ethanol, 2-methoxyethanol and isopropanol are highly volatile and can effectively promote the growth of perovskite grains, which is beneficial for the rapid film formation of the perovskite precursor solution after coating, thereby accelerating the preparation of the perovskite layer 4 and reducing preparation time and cost.

[0077] Further preferably, the first solvent is composed of acetonitrile and 2-methoxyethanol in a volume ratio of (0.25-0.82): 1. For example, the volume ratio of acetonitrile and 2-methoxyethanol can be 0.25:1, 0.3:1, 0.35:1, 0.45:1, 0.55:1, 0.65:1, 0.75:1, 0.82:1, etc.

[0078] In some embodiments, the concentration of the perovskite precursor solution is 0.8 mol / mL to 2 mol / mL.

[0079] The perovskite precursor solution at the above concentration has a high viscosity, good adhesion to the large-area pyramid velvet substrate, and high crystallization quality after coating, resulting in good film quality. For example, the concentration of the perovskite precursor solution can be 0.8 mol / mL, 1 mol / mL, 1.2 mol / mL, 1.4 mol / mL, 1.6 mol / mL, 1.8 mol / mL, and 2 mol / mL, etc.

[0080] In a second aspect, an embodiment of the present application provides a method for preparing a perovskite layer 4.

[0081] The preparation method of the perovskite layer 4 is as follows:

[0082] providing a substrate having a pyramid pile surface;

[0083] A perovskite precursor solution is coated on a substrate to form a perovskite wet film layer, and an airflow with a temperature of 80°C to 130°C and a wind pressure of 1MPa to 2MPa is blown toward the perovskite wet film layer, wherein the temperature of the airflow is not lower than the boiling point of the first solvent, to obtain a perovskite layer 4.

[0084] When the above-mentioned perovskite precursor solution is used on a pyramid velvet substrate, it can achieve rapid crystallization in situ. It can be seen that the above-mentioned perovskite precursor solution is suitable for use on a pyramid velvet substrate, and has excellent applicability to pyramid heights of 2μm to 6μm. For example, the pyramid height of the velvet can be 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, 6.5μm, 6μm, etc.

[0085] In some embodiments, the thickness of the perovskite layer 4 is 800 nm to 1500 nm.

[0086] The perovskite layer 4 of this thickness, prepared from a perovskite precursor solution, exhibits excellent conformal growth and light absorption, which is beneficial for enhancing the light absorption of solar cells. For example, the thickness of the perovskite layer 4 can be 800 nm, 900 nm, 1000 nm, 1100 nm, 1200 nm, 1300 nm, 1400 nm, 1500 nm, etc.

[0087] In some embodiments, the coating method of the perovskite precursor solution includes any one of slit coating, screen printing and doctor blade coating; and / or,

[0088] The coating speed of the perovskite precursor solution is 5 mm / s to 20 mm / s; and / or,

[0089] After the perovskite precursor solution is applied, the thickness of the formed perovskite wet film layer is 5 μm to 10 μm; and / or,

[0090] The gas flow is nitrogen or an inert gas.

[0091] When the perovskite layer 4 is prepared by slit coating, screen printing, and doctor blade coating, the perovskite precursor solution has better adhesion to the large-area pyramid velvet substrate, which is conducive to achieving a uniform shape retention effect. When spraying or spin coating is used, the perovskite precursor solution has poor adhesion to the large-area pyramid velvet substrate, which is not conducive to achieving a uniform shape retention effect.

[0092] When the coating speed is 5 mm / s to 20 mm / s, the perovskite precursor solution is coated with good continuity and is not easily accumulated, which is conducive to forming a perovskite layer 4 with excellent crystalline quality. When the coating speed is too high, it is easy to cause the perovskite precursor solution to be discontinuous. When the coating speed is too slow, it is easy to cause the perovskite precursor solution to accumulate, thereby reducing the quality of the perovskite layer 4. Exemplary coating speeds are 5 mm / s, 7 mm / s, 9 mm / s, 11 mm / s, 13 mm / s, 15 mm / s, 17 mm / s, and 20 mm / s.

[0093] After coating, the perovskite precursor solution forms a thick wet film. In a thicker perovskite layer 4, the perovskite precursor solution is less likely to deposit from the top to the bottom of the pyramid velvet substrate. This allows for the formation of a perovskite layer 4 that is both thicker and better in shape retention, thereby enhancing the light absorption and electron transport capabilities of the perovskite layer 4. For example, the wet film thickness is 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and 10 μm.

[0094] In some embodiments, when the slit coating method is used, the slit size is controlled to be 70 μm to 110 μm.

[0095] By controlling the slit size to be 70 μm to 110 μm, it is beneficial for the perovskite precursor solution with higher viscosity to flow out, and it is also beneficial for forming a thicker perovskite layer 4 , thereby improving the light absorption capacity of the perovskite layer 4 .

[0096] For example, the slit size may be 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, etc.

[0097] In a third aspect, an embodiment of the present application provides a perovskite tandem solar cell.

[0098] 1 , the perovskite tandem solar cell includes a silicon substrate cell and a first transparent conductive layer 2, a hole transport layer 3, a perovskite layer 4, an electron transport layer 5, and a second transparent conductive layer 6 stacked in sequence on the silicon substrate cell. The perovskite layer 4 is prepared by the preparation method of the perovskite layer 4 of the second aspect. The perovskite tandem solar cell also includes a positive electrode 71 and a negative electrode 72. The positive electrode 71 forms an ohmic contact with the electron transport layer 5, and the negative electrode 72 forms an ohmic contact with the silicon substrate cell.

[0099] The above-mentioned perovskite precursor solution has a fast volatilization speed, strong adhesion and slow flow speed. It can evaporate quickly and can quickly crystallize into a film in situ, which is beneficial to reducing the process time and improving production efficiency.

[0100] The first transparent conductive layer 2 or the second transparent conductive layer 6 may be an indium tin oxide layer or an indium zinc oxide layer, the hole transport layer 3 may be a nickel oxide layer, and the electron transport layer 5 may be a C60 layer.

[0101] 2 , in some embodiments, a hole modification layer 31 is further provided between the perovskite layer 4 and the hole transport layer 3; and / or, a passivation layer 41 is further provided between the perovskite layer 4 and the electron transport layer 5; and / or, a buffer layer 51 is further provided on the electron transport layer 5 facing away from the silicon substrate battery, and an anti-reflection layer 8 is further provided on the side of the second transparent conductive layer 6 facing away from the silicon substrate battery.

[0102] The hole modification layer 31 may be a 2PACz layer, the passivation layer 41 may be a lithium fluoride layer or a 2-thiopheneethylamine bromide salt layer, the buffer layer 51 may be a tin dioxide layer, and the anti-reflection layer 8 may be lithium fluoride or magnesium fluoride.

[0103] The thickness of the hole transport layer 3 is 15nm~25nm; and / or, the thickness of the electron transport layer 5 is 10nm~20nm; and / or, the thickness of the hole modification layer 31 is 1nm~5nm; and / or, the thickness of the passivation layer 41 is 1nm~3nm; and / or, the thickness of the buffer layer 51 is 10nm~20nm, and the thickness of the anti-reflection layer 8 is 90nm~120nm.

[0104] For example, the thickness of the hole transport layer 3 can be 15 nm, 17 nm, 19 nm, 21 nm, 23 nm, and 25 nm. The thickness of the hole modification layer 31 can be 1 nm, 2 nm, 3 nm, 4 nm, and 5 nm. The thickness of the passivation layer 41 can be 1 nm, 1.5 nm, 2.5 nm, and 3 nm. The thickness of the buffer layer 51 can be 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, and 20 nm. The thickness of the anti-reflection layer 8 can be 90 nm, 95 nm, 100 nm, 105 nm, 110 nm, 115 nm, and 120 nm.

[0105] In a fourth aspect, an embodiment of the present application provides a method for preparing a perovskite tandem solar cell, the perovskite tandem solar cell comprising the following steps:

[0106] Provide silicon substrate cells;

[0107] Prepare a first transparent conductive layer 2 on the front side of the silicon substrate battery;

[0108] A hole transport layer 3 is formed on the first transparent conductive layer 2;

[0109] A perovskite layer 4 is prepared on the hole transport layer 3. The perovskite layer 4 is prepared by the preparation method of the perovskite layer 4 according to the second aspect.

[0110] An electron transport layer 5 is formed on the perovskite layer 4;

[0111] A second transparent conductive layer 6 is formed on the electron transport layer 5

[0112] A positive electrode 71 is prepared on the second transparent conductive layer 6, and a negative electrode 72 is prepared on the back of the silicon substrate cell to obtain the above-mentioned perovskite tandem solar cell.

[0113] The perovskite layer 4 prepared by the above method has excellent crystallization performance, high thickness and good shape retention effect, and does not require annealing treatment as in the traditional solution method for preparing perovskite. Therefore, the above perovskite tandem solar cell has excellent energy conversion efficiency, shortens the preparation time, and improves production efficiency.

[0114] In some embodiments, a hole modification layer 31 is further prepared between the hole transport layer 3 and the perovskite layer 4, a passivation layer 41 is further prepared between the perovskite layer 4 and the electron transport layer 5, and a buffer layer 51 is further prepared on the side of the electron transport layer 5 facing away from the silicon substrate battery; and / or,

[0115] The hole transport layer 3 , the hole modification layer 31 , the passivation layer 41 , the electron transport layer 5 and / or the buffer layer 51 are prepared by slit coating.

[0116] The functional layers such as the hole transport layer 3 , the hole modification layer 31 , the passivation layer 41 , the electron transport layer 5 and the buffer layer 51 can all be prepared by slit coating.

[0117] During the slit coating process, a device that links a slit knife head with an air knife can be used. Multiple knife heads can be linked to the air knife. The slit knife heads corresponding to different film layers use different coating processes, and the corresponding air knife heating temperatures and air knife airflow rates are different. When the slit knife head is finished coating, the air knife heating assists the evaporation of the solvent, speeds up the film formation speed, reduces the subsequent back-processing process, realizes the rapid deposition of multi-layer films, and reduces time costs.

[0118] Specifically, in the process of sequentially preparing the hole transport layer 3, the electron transport layer 5, the hole modification layer 31, the passivation layer 41 and the buffer layer 51 by the above-mentioned slit coating method, the raw materials of the hole transport layer 3, the electron transport layer 5, the hole modification layer 31, the passivation layer 41 and the buffer layer 51 are first respectively prepared into solutions of appropriate concentrations with the aid of a certain volatile solvent, and the solutions are evenly pushed to the slit coating blade, the carrier moves at a constant speed, and the solution is evenly coated on the surface of the substrate with a pyramid velvet surface to form a wet film, and the uniformity and thickness of the above-mentioned film layers are controlled by adjusting parameters such as the slit size, the wet film thickness, the starting and ending positions of the coating, the coating speed, and the filling time. The wet film after coating is subjected to heated airflow to assist the volatilization of the solvent, thereby accelerating the crystallization growth of the film layer, achieving the shape retention of the film layer and forming the desired thin film.

[0119] In some embodiments, the hole transport layer 3 is prepared by dissolving an aqueous solution of nickel oxide nanocrystals in a volatile solvent to obtain a nickel oxide nanocrystal solution, then coating the nickel oxide nanocrystal solution to form a wet film of the hole transport layer 3, and then blowing an airflow at a temperature of 50° C. to 70° C. and a wind pressure of 0.8 MPa to 1.2 MPa toward the surface of the wet film of the hole transport layer 3 to obtain the hole transport layer 3, wherein the volatile solvent is one or more of ethanol, acetonitrile and isopropyl alcohol; and / or,

[0120] The preparation method of the electron transport layer 5 is as follows: 60 Dissolve in chlorobenzene, add ethanol to obtain a C60 solution, then apply the C60 solution to form a wet film of the electron transport layer 5, and then blow an airflow with a temperature of 40° C. to 60° C. and a wind pressure of 0.6 MPa to 1 MPa toward the surface of the wet film of the electron transport layer 5 to obtain the electron transport layer 5; and / or,

[0121] The hole modification layer 31 is prepared by dissolving 2PACz in ethanol to obtain a 2PACz solution, then coating the 2PACz solution to form a wet film of the hole modification layer 31, and then blowing an air flow at a temperature of 40° C. to 50° C. and a wind pressure of 0.2 MPa to 0.5 MPa toward the surface of the wet film of the hole modification layer 31 to obtain the hole modification layer 31; and / or,

[0122] A passivation layer 41 is also prepared between the perovskite layer 4 and the electron transport layer 5. The preparation method of the passivation layer 41 is as follows: dissolving 2-thiopheneethylamine bromide in isopropyl alcohol to obtain a 2-thiopheneethylamine bromide solution, then coating the 2-thiopheneethylamine bromide solution to form a wet film of the passivation layer 41, and then blowing an airflow with a temperature of 50°C to 60°C and a wind pressure of 0.4MPa to 0.6MPa toward the surface of the wet film of the passivation layer 41 to obtain the passivation layer 41; and / or,

[0123] The preparation method of the buffer layer 51 is as follows: a tin dioxide hydrocolloid solution is dissolved in a mixed solvent of water and ethanol to obtain a tin dioxide solution, and then the tin dioxide solution is applied to form a wet film of the buffer layer 51, and then an air flow with a temperature of 50°C to 70°C and a wind pressure of 0.5MPa to 1MPa is blown toward the surface of the wet film of the buffer layer 51 to obtain the buffer layer 51.

[0124] In some embodiments, during the preparation of the hole transport layer 3, the concentration of the nickel oxide nanocrystalline solution is 10 mg / mL to 15 mg / mL, the slit spacing is 50 μm to 80 μm, the coating speed is 7 mm / s to 14 mm / s, and the thickness of the wet film of the hole transport layer 3 is 2 μm to 5 μm; and / or,

[0125] During the preparation of the electron transport layer 5, C 60The concentration of the solution is 0.8 mg / ml to 2.0 mg / ml, the slit spacing is 30 μm to 70 μm, the coating speed is 7 mm / s to 14 mm / s, and the thickness of the wet film of the electron transport layer 5 is 4 μm to 7 μm; and / or,

[0126] During the preparation of the hole modification layer 31, the concentration of the 2PACz solution is 0.1 mg / ml to 0.5 mg / ml, the slit spacing is 15 μm to 25 μm, the coating speed is 10 mm / s to 20 mm / s, and the thickness of the wet film of the passivation layer 41 is 1 μm to 3 μm; and / or,

[0127] During the preparation of the passivation layer 41, the concentration of the 2-thiopheneethylamine bromide solution is 0.8 mg / ml to 2.0 mg / ml, the slit spacing is 20 μm to 40 μm, the coating speed is 15 mm / s to 25 mm / s, and the thickness of the wet film of the passivation layer 41 is 1 μm to 4 μm; and / or,

[0128] During the preparation of the buffer layer 51 , the concentration of the tin dioxide hydrocolloid solution is 1.5% to 5%, the slit spacing is 50 μm to 80 μm, the coating speed is 7 mm / s to 14 mm / s, and the wet film thickness of the passivation layer 41 is 1 μm to 5 μm.

[0129] The technical solution of the present application is described below with reference to more specific embodiments and drawings.

[0130] Example 1

[0131] The present invention provides a perovskite tandem solar cell, comprising:

[0132] Heterojunction bottom cell 1, the pyramid velvet height of the heterojunction bottom cell is 5μm;

[0133] A first transparent electrode layer stacked on the front of the heterojunction bottom cell 1, wherein the material of the first transparent electrode layer is indium tin oxide and the thickness is 90 nm;

[0134] A hole transport layer 3 is stacked on the side of the transparent electrode layer facing away from the heterojunction bottom cell 1. The hole transport layer 3 is made of nickel oxide and has a thickness of 17 nm.

[0135] The hole modification layer 31 is stacked on the side of the hole transport layer 3 facing away from the heterojunction bottom cell 1. The hole modification layer 31 is made of a material with a thickness of 2 nm;

[0136] The perovskite layer 4 stacked on the side of the hole modification layer 31 away from the heterojunction bottom cell 1 has a thickness of 1000 nm;

[0137] A passivation layer 41 is stacked on the side of the perovskite layer 4 facing away from the heterojunction bottom cell 1. The passivation layer 41 is made of 2-thiopheneethylamine bromide and has a thickness of 1.5 nm.

[0138] The electron transport layer 5 is stacked on the side of the passivation layer 41 away from the heterojunction bottom battery 1. The electron transport layer 5 is made of C60 and has a thickness of 15 nm.

[0139] A buffer layer 51 is stacked on the side of the electron transport layer 5 facing away from the heterojunction bottom cell 1. The buffer layer 51 is made of tin dioxide and has a thickness of 15 nm.

[0140] A second transparent electrode layer stacked on the side of the buffer layer 51 away from the heterojunction bottom cell 1, the second transparent electrode layer is zinc indium oxide and has a thickness of 100 nm;

[0141] An anti-reflection layer 8 is stacked on the side of the second transparent electrode layer facing away from the heterojunction bottom cell 1. The anti-reflection layer 8 is made of magnesium fluoride and has a thickness of 110 nm.

[0142] It also includes a positive electrode 71 and a negative electrode 72. Both the positive electrode 71 and the negative electrode 72 are silver electrodes. The thickness of the positive electrode 71 and the negative electrode 72 are 275 nm respectively. The positive electrode 71 forms an ohmic contact with the transparent electrode layer, and the negative electrode 72 forms an ohmic contact with the heterojunction bottom battery 1.

[0143] The preparation method of the above-mentioned perovskite tandem solar cell is as follows:

[0144] Providing a heterojunction bottom cell 1;

[0145] A first transparent conductive layer 2 is prepared on the front side of the heterojunction bottom cell 1 by magnetron sputtering;

[0146] A hole transport layer 3, a hole modification layer 31, a perovskite layer 4, a passivation layer 41, an electron transport layer 5 and a buffer layer 51 are sequentially prepared on the first transparent conductive layer 2 by a slit coating method. The specific steps are as follows:

[0147] Preparation of hole transport layer 3: An aqueous solution of nickel oxide nanocrystals was dissolved in ethanol to obtain a nickel oxide nanocrystal solution with a concentration of 10 mg / mL to 15 mg / mL. The nickel oxide nanocrystal solution was then applied using a slit coating method to form a wet film of hole transport layer 3. The slit spacing was 60 μm, the coating speed was 10 mm / s, and the thickness of the wet film of hole transport layer 3 was 3 μm. An airflow at a temperature of 60°C and a pressure of 1 MPa was then blown toward the surface of the wet film of hole transport layer 3 to form hole transport layer 3.

[0148] Preparation of the hole modification layer 31: 2PACz was dissolved in ethanol to obtain a 2PACz solution with a concentration of 0.1 mg / ml to 0.5 mg / ml. The 2PACz solution was then coated using a slit coating method to form a wet film of the hole modification layer 31, wherein the slit spacing was 20 μm and the coating speed was 15 mm / s. The thickness of the wet film of the passivation layer 41 was 1.5 μm. An air flow with a temperature of 45°C and a pressure of 0.3 MPa was then blown toward the surface of the wet film of the hole modification layer 31 to obtain the hole modification layer 31.

[0149] Preparation of perovskite layer 4: Perovskite material Cs 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23 )3 is dissolved in a mixed solvent to obtain a perovskite precursor solution with a concentration of 0.8 mg / ml to 2.0 mg / ml, wherein the mixed solvent is composed of a second solvent with a volume proportion of 80% and a first solvent with a volume proportion of 20%, the second solvent is composed of dimethyl sulfoxide and 1,8-diiodooctane with a mass ratio of 0.6:1, and the first solvent is composed of acetonitrile and 2-methoxyethanol with a mass ratio of 0.4:1. The perovskite precursor solution is coated on the hole modification layer 31 to form a perovskite wet film layer, and an airflow with a temperature of 120°C and a wind pressure of 1.5 MPa is blown toward the perovskite wet film layer, and the temperature of the airflow is not lower than the boiling point of the first solvent to obtain the perovskite layer 4.

[0150] Preparation of the passivation layer 41: dissolving 2-thiopheneethylamine bromide in isopropyl alcohol to obtain a 2-thiopheneethylamine bromide solution having a concentration of 0.8 mg / ml to 2.0 mg / ml, then coating the 2-thiopheneethylamine bromide solution to form a wet film of the passivation layer 41, wherein the slit spacing is 30 μm, the coating speed is 20 mm / s, and the thickness of the wet film of the passivation layer 41 is 2 μm; then blowing an airflow at a temperature of 55° C. and a wind pressure of 0.5 MPa toward the surface of the wet film of the passivation layer 41 to obtain the passivation layer 41; and / or,

[0151] Preparation of electron transport layer 5: C60 was dissolved in chlorobenzene and added with ethanol to obtain a C60 solution with a concentration of 0.8 mg / ml to 2.0 mg / ml, and then the C60 solution was coated to form a wet film of electron transport layer 5, wherein the slit spacing was 50 μm, the coating speed was 10 mm / s, and the thickness of the wet film of electron transport layer 5 was 5 μm. Subsequently, an air flow with a temperature of 50° C. and a wind pressure of 0.8 MPa was blown toward the surface of the wet film of electron transport layer 5 to prepare electron transport layer 5;

[0152] Preparation of buffer layer 51: A tin dioxide hydrocolloid solution was dissolved in a mixed solvent of water and ethanol to obtain a tin dioxide solution with a concentration of 1.5% to 5%. The tin dioxide solution was then applied to form a wet film of buffer layer 51. The slit spacing was 60 μm, the coating speed was 10 mm / s, and the thickness of the wet film of passivation layer 41 was 3 μm. An airflow at a temperature of 60°C and a wind pressure of 0.7 MPa was then blown toward the wet film surface of buffer layer 51 to obtain buffer layer 51.

[0153] A second transparent electrode layer is formed on the buffer layer 51 by magnetron sputtering;

[0154] A positive electrode 71 is evaporated on the second transparent electrode layer to form an ohmic contact between the positive electrode 71 and the second transparent electrode layer;

[0155] A negative electrode 72 is evaporated on the back of the heterojunction bottom battery 1 to form an ohmic contact between the negative electrode 72 and the heterojunction bottom battery 1;

[0156] An anti-reflection layer 8 is formed on the second transparent electrode layer by using an evaporation method.

[0157] Example 2

[0158] The embodiment of the present application provides a perovskite tandem solar cell, which differs from the first embodiment in that in the step of preparing the perovskite layer 4, the volume proportion of the second solvent is 90%, and the volume proportion of the first solvent is 10%, and the rest is consistent with the first embodiment.

[0159] Example 3

[0160] This embodiment of the present application provides a perovskite tandem solar cell, which differs from the first embodiment in that:

[0161] In the step of preparing the perovskite layer 4 , the volume proportion of the second solvent is 70%, the volume proportion of the first solvent is 30%, and the rest is consistent with the first embodiment.

[0162] Example 4

[0163] This embodiment of the present application provides a perovskite tandem solar cell, which differs from the first embodiment in that:

[0164] In the step of preparing the perovskite layer 4 , the volume proportion of the second solvent is 40%, the volume proportion of the first solvent is 60%, and the rest is consistent with the first embodiment.

[0165] Example 5

[0166] This embodiment of the present application provides a perovskite tandem solar cell, which differs from the first embodiment in that:

[0167] In the step of preparing the perovskite layer 4, the second solvent is dimethyl sulfoxide, and the rest is consistent with the first embodiment.

[0168] Comparative Example 1

[0169] The comparative example of the present application provides a perovskite tandem solar cell, which differs from the first embodiment in that:

[0170] In the step of preparing the perovskite layer 4 , only the second solvent is used as the mixed solvent, and the first solvent is not used. The rest is consistent with the first embodiment.

[0171] Comparative Example 2

[0172] The comparative example of the present application provides a perovskite tandem solar cell, which differs from the first embodiment in that:

[0173] In the step of preparing the perovskite layer 4 , only the first solvent is used as the mixed solvent, and the second solvent is not used. The rest is consistent with the first embodiment.

[0174] Experiment 1

[0175] The perovskite layer of Example 1 was subjected to SEM scanning, and the results are shown in FIG3 .

[0176] As can be seen from FIG3 , the perovskite layer grows conformally along the pyramid velvet surface, which proves that the perovskite layer prepared on the pyramid velvet surface substrate using the above-mentioned perovskite precursor solution has a better conformal effect.

[0177] Experiment 2

[0178] The performance of perovskite tandem solar cells was tested using a Wavelabs solar simulator. Test conditions: AM1.5, 1000W / m 2 The test environment temperature was 25°C. Before testing, the simulated sunlight intensity of the light source was calibrated using a standard silicon cell. Performance tests included power conversion efficiency (PCE), open-circuit voltage (Voc), short-circuit current (Jsc), and fill factor (FF).

[0179] Table 1

[0180] From the data in Table 1, it can be seen that compared with the comparative example 1, the PCE of the perovskite tandem solar cell of Example 1 is increased by 1.85%, Voc is increased by 0.063V, FF is increased by 3.08%, and Jsc is reduced by 0.21mA / cm 2, proving that in the perovskite precursor solution, when the mixed solvent only uses the second solvent with a higher viscosity without adding the first solvent with a lower boiling point, the resulting perovskite layer has poor crystallization quality, resulting in a significant decrease in the Voc and FF of the perovskite layer, and ultimately a significant decrease in the PCE of the perovskite tandem solar cell. Compared with Comparative Example 2, the PCE of the perovskite tandem solar cell of Example 1 increased by 3.28%, Voc increased by 0.09V, FF increased by 5.21%, and Jsc decreased by 0.02mA / cm 2 , which proves that in the perovskite precursor solution, if the mixed solvent only uses the first solvent with a lower boiling point without adding the second solvent with a higher viscosity, the crystallization quality of the perovskite layer obtained will also decrease, and the shape retention effect of the perovskite layer will be relatively reduced, resulting in a significant decrease in the Voc, FF and PCE of the perovskite layer.

[0181] Combining the test results of Example 1, Comparative Example 1 and Comparative Example 2, it can be seen that when a specific proportion of a first solvent with a lower boiling point is combined with a second solvent with a higher viscosity as a mixed solvent, the perovskite layer prepared from the perovskite precursor solution can achieve conformal coverage on the surface of the pyramid velvet substrate, and at the same time obtain a better crystallization effect, breaking through the conformal effect of preparing the perovskite layer on the pyramid velvet substrate by the solution method. At the same time, by adopting a wind knife heating process immediately after coating, the perovskite layer prepared by the perovskite precursor solution does not need to be annealed, and can be rapidly crystallized and grown in situ, thereby obtaining a perovskite layer with excellent crystallization quality.

[0182] The above is a detailed introduction to the perovskite precursor solution, the preparation method of the perovskite layer, the perovskite tandem solar cell and the preparation method thereof disclosed in the embodiments of the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the perovskite precursor solution, the preparation method of the perovskite layer, the perovskite tandem solar cell and the preparation method thereof and their core ideas of the present invention: At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A perovskite precursor solution, comprising a perovskite material and a mixed solvent, wherein the viscosity of the mixed solvent is 2mPa·s to 3.5mPa·s, the mixed solvent comprises a first solvent, the volume of the first solvent accounts for 10% to 40% of the mixed solvent, and the boiling point of the first solvent is 80°C to 130°C.

2. The perovskite precursor solution according to claim 1, wherein The mixed solvent further includes a second solvent, and the second solvent includes one or both of dimethyl sulfoxide and 1,8-diiodooctane.

3. The perovskite precursor solution according to claim 2, wherein: The second solvent is composed of the dimethyl sulfoxide and the 1,8-diiodooctane in a mass ratio of (0.4-0.8):

1.

4. The perovskite precursor solution according to any one of claims 1 to 3, wherein: The first solvent includes one or more of acetonitrile, ethanol, 2-methoxyethanol and isopropanol.

5. The perovskite precursor solution according to claim 4, wherein: The first solvent is composed of the acetonitrile and the 2-methoxyethanol in a volume ratio of (0.25-0.82):

1.

6. The perovskite precursor solution according to any one of claims 1 to 5, wherein: The concentration of the perovskite precursor solution is 0.8 mol / mL to 2 mol / mL.

7. A method for preparing a perovskite layer, comprising the following steps: providing a substrate having a pyramid pile surface; A perovskite precursor solution as described in any one of claims 1 to 6 is coated on the substrate to form a perovskite wet film layer, and an airflow with a temperature of 80°C to 130°C and a wind pressure of 1MPa to 2MPa is blown toward the perovskite wet film layer, wherein the temperature of the airflow is not lower than the boiling point of the first solvent, to obtain the perovskite layer. 8 . The method for preparing a perovskite layer according to claim 7 , wherein the thickness of the perovskite layer is 800 nm to 1500 nm.

9. The method for preparing a perovskite layer according to any one of claims 7 to 8, wherein: The coating method of the perovskite precursor solution includes any one of slit coating, screen printing and blade coating.

10. The method for preparing a perovskite layer according to claim 9, wherein: When the slit coating method is used, the slit size is controlled to be 70 μm to 110 μm.

11. The method for preparing a perovskite layer according to any one of claims 7 to 10, wherein: The coating speed of the perovskite precursor solution is 5 mm / s to 20 mm / s.

12. The method for preparing a perovskite layer according to any one of claims 7 to 11, wherein: After the perovskite precursor solution is coated, the perovskite wet film layer formed has a thickness of 5 μm to 10 μm.

13. The method for preparing a perovskite layer according to any one of claims 7 to 12, wherein: The gas flow is nitrogen or an inert gas.

14. A perovskite tandem solar cell, comprising a silicon base cell and a first transparent conductive layer, a hole transport layer, a perovskite layer, an electron transport layer and a second transparent conductive layer stacked in sequence on the silicon base cell, wherein the perovskite layer is prepared by the method for preparing a perovskite layer according to any one of claims 7 to 13, and the perovskite tandem solar cell further comprises a positive electrode and a negative electrode, wherein the positive electrode forms an ohmic contact with the electron transport layer, and the negative electrode forms an ohmic contact with the silicon base cell.

15. The perovskite tandem solar cell according to claim 14, wherein: A hole modification layer is also provided between the perovskite layer and the hole transport layer.

16. The perovskite tandem solar cell according to any one of claims 14 to 15, wherein: A passivation layer is further disposed between the perovskite layer and the electron transport layer.

17. The perovskite tandem solar cell according to any one of claims 14 to 16, wherein: A buffer layer is also arranged on the electron transport layer away from the silicon substrate battery.

18. The perovskite tandem solar cell according to any one of claims 14 to 17, wherein: An anti-reflection layer is also arranged on the side of the second transparent conductive layer facing away from the silicon substrate cell.

19. The perovskite tandem solar cell according to claims 14 to 18, wherein: The thickness of the hole transport layer is 15 nm to 25 nm.

20. The perovskite tandem solar cell according to claims 14 to 19, wherein: The thickness of the electron transport layer is 10 nm to 20 nm.

21. The perovskite tandem solar cell according to claims 14 to 20, wherein: The thickness of the hole modification layer is 1 nm to 5 nm.

22. The perovskite tandem solar cell according to claims 14 to 21, wherein: The thickness of the passivation layer is 1 nm to 3 nm.

23. The perovskite tandem solar cell according to claims 14 to 22, wherein: The thickness of the buffer layer is 10 nm to 20 nm.

24. The perovskite tandem solar cell according to claims 14 to 23, wherein: The thickness of the anti-reflection layer is 90nm-120nm.

25. A method for preparing a perovskite tandem solar cell, comprising the following steps: Provide silicon substrate cells; Prepare a hole transport layer on the front side of the silicon substrate battery; Preparing a perovskite layer on the hole transport layer, wherein the perovskite layer is prepared by the method for preparing a perovskite layer according to the second aspect; preparing an electron transport layer on the perovskite layer; A positive electrode and a negative electrode are prepared on the electron transport layer to obtain the perovskite tandem solar cell according to any one of claims 14 to 25.

26. The method for preparing a perovskite tandem solar cell according to claim 25, wherein: A hole modification layer is prepared between the hole transport layer and the perovskite layer, a passivation layer is prepared between the perovskite layer and the electron transport layer, a buffer layer is prepared on the side of the electron transport layer facing away from the silicon substrate battery, and an anti-reflection layer is provided on the side of the second transparent conductive layer facing away from the silicon substrate battery.

27. The method for preparing a perovskite tandem solar cell according to claim 26, wherein: The hole transport layer, the hole modification layer, the passivation layer, the electron transport layer and / or the buffer layer are prepared by slit coating.

28. The method for preparing a perovskite tandem solar cell according to claim 27, wherein: The preparation method of the hole transport layer is as follows: dissolving a nickel oxide nanocrystal aqueous solution in a volatile solvent to obtain a nickel oxide nanocrystal solution, then coating the nickel oxide nanocrystal solution to form a hole transport layer wet film, and then blowing an airflow with a temperature of 50°C to 70°C and a wind pressure of 0.8MPa to 1.2MPa toward the surface of the hole transport layer wet film to obtain the hole transport layer, wherein the volatile solvent is one or more of ethanol, acetonitrile and isopropanol.

29. The method for preparing a perovskite tandem solar cell according to claim 28, wherein: During the preparation of the hole transport layer, the concentration of the nickel oxide nanocrystalline solution is 10 mg / mL to 15 mg / mL, the slit spacing is 50 μm to 80 μm, the coating speed is 7 mm / s to 14 mm / s, and the thickness of the hole transport layer wet film is 2 μm to 5 μm.

30. The method for preparing a perovskite tandem solar cell according to any one of claims 27 to 29, wherein: The preparation method of the electron transport layer is as follows: 60 Dissolve in chlorobenzene and add ethanol to obtain C 60 solution, followed by coating C 60 The solution is used to form a wet film of an electron transport layer, and then an airflow with a temperature of 40° C. to 60° C. and a wind pressure of 0.6 MPa to 1 MPa is blown toward the surface of the wet film of the electron transport layer to obtain the electron transport layer.

31. The method for preparing a perovskite tandem solar cell according to claim 30, wherein: During the preparation of the electron transport layer, the C 60 The concentration of the solution is 0.8 mg / ml to 2.0 mg / ml, the slit spacing is 30 μm to 70 μm, the coating speed is 7 mm / s to 14 mm / s, and the thickness of the wet film of the electron transport layer is 4 μm to 7 μm.

32. The method for preparing a perovskite tandem solar cell according to any one of claims 27 to 31, wherein: The preparation method of the hole modification layer is as follows: dissolving 2PACz in ethanol to obtain a 2PACz solution, then coating the 2PACz solution to form a hole modification layer wet film, and then blowing an airflow with a temperature of 40°C to 50°C and a wind pressure of 0.2MPa to 0.5MPa toward the surface of the hole modification layer wet film to obtain the hole modification layer.

33. The method for preparing a perovskite tandem solar cell according to claim 32, wherein: During the preparation of the hole modification layer, the concentration of the 2PACz solution is 0.1 mg / ml to 0.5 mg / ml, the slit spacing is 15 μm to 25 μm, the coating speed is 10 mm / s to 20 mm / s, and the thickness of the passivation layer wet film is 1 μm to 3 μm.

34. The method for preparing a perovskite tandem solar cell according to any one of claims 27 to 33, wherein: A passivation layer is also prepared between the perovskite layer and the electron transport layer. The preparation method of the passivation layer is as follows: 2-thiopheneethylamine bromide is dissolved in isopropanol to obtain a 2-thiopheneethylamine bromide solution, and then the 2-thiopheneethylamine bromide solution is applied to form a passivation layer wet film, and then an airflow with a temperature of 50°C to 60°C and a wind pressure of 0.4MPa to 0.6MPa is blown toward the surface of the passivation layer wet film to obtain the passivation layer.

35. The method for preparing a perovskite tandem solar cell according to claim 34, wherein: During the preparation of the passivation layer, the concentration of the 2-thiopheneethylamine bromide salt solution is 0.8 mg / ml to 2.0 mg / ml, the slit spacing is 20 μm to 40 μm, the coating speed is 15 mm / s to 25 mm / s, and the thickness of the wet film of the passivation layer is 1 μm to 4 μm.

36. The method for preparing a perovskite tandem solar cell according to any one of claims 27 to 35, wherein: The preparation method of the buffer layer is as follows: dissolving a tin dioxide hydrocolloid solution in a mixed solvent of water and ethanol to obtain a tin dioxide solution, then coating the tin dioxide solution to form a buffer layer wet film, and then blowing an airflow with a temperature of 50°C to 70°C and a wind pressure of 0.5MPa to 1MPa toward the surface of the buffer layer wet film to obtain the buffer layer.

37. The method for preparing a perovskite tandem solar cell according to claim 36, wherein: During the preparation of the buffer layer, the concentration of the tin dioxide hydrocolloid solution is 1.5% to 5%, the slit spacing is 50 μm to 80 μm, the coating speed is 7 mm / s to 14 mm / s, and the thickness of the passivation layer wet film is 1 μm to 5 μm.

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