Screening method of perovskite precursor solution additive, perovskite precursor solution and battery

Abstract

The invention discloses a screening method of a perovskite precursor solution additive, a perovskite precursor solution and a battery, and relates to the field of batteries. The screening method comprises the following steps: analyzing a solvent and a solute of a base solution of a perovskite precursor solution, and screening an additive which does not dissolve any component in the solute, is mutually miscible with the solvent, has surface tension lower than that of the base solution of the perovskite precursor solution and has a difference of 20 DEG C or more from the base solution of the perovskite precursor solution at normal pressure from various alternative additives as a target additive. The screened target additive does not damage the original solute-solvent system, and can improve the wetting efficiency and adjust the volatile performance of the perovskite precursor solution on the premise of not influencing the crystallization performance of the hybrid perovskite solar cell precursor solution, thereby improving the comprehensive performance of the precursor solution.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a method for screening a perovskite precursor solution additive, a perovskite precursor solution and a battery. Background Art

[0002] At present, the efficiency of perovskite solar cells (PSC) has reached 25.7%, surpassing traditional polycrystalline silicon solar cells and becoming a rising star in the photovoltaic industry. Compared with traditional silicon photovoltaic technology, its major advantage is that it can be processed in low-temperature solutions, which can significantly reduce the difficulty of the process, reduce costs, and realize the preparation of large-area thin films and photovoltaic devices.

[0003] In the process of wet preparation of perovskite battery devices, the preparation of precursor solution is one of the key processes. At present, the most commonly used solvent systems of perovskite precursor solutions are divided into two categories. One is based on DMF, and strong coordinating low-volatility solvents such as DMSO or NMP are used as crystallization aids, and the other is based on high-volatility solvents such as 2-ME, while additives are used to assist film formation. The former type of solvent system is more versatile, but its viscosity is generally higher and its wettability is poor. In the spin coating process, the substrate needs to be additionally rinsed, and its wettability is limited in large-area film-making processes; in addition, this type of system evaporates slowly and is prone to solvent residues. The latter type of solvent is limited by its poor solubility in raw materials containing elements such as Cs and Br, and is only suitable for narrow-bandgap perovskite systems, and is difficult to apply to wide-bandgap perovskite systems and the preparation of stacked solar cells.

[0004] The current mainstream solution to the problem of improving the processability of the precursor solution is to use surfactants to increase its wettability and to use strongly coordinated solid / liquid additives to control the boiling point and volatility of the precursor solution. However, the use of surfactants will cause its components to remain in the perovskite film, causing defects that affect device performance; the use of strongly coordinated additives will seriously affect the perovskite crystallization process, and it will take a long time to optimize the optimal film-forming conditions for each ratio of additives, affecting the processing window time and the implementation of large-area film-making processes.

[0005] In summary, regulating the solvent parameters of the hybrid perovskite precursor solution on the basis of minimizing interference with the perovskite crystallization process to achieve improved processability is of great significance for the mass production of perovskite batteries.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The purpose of the present invention is to provide a method for screening a perovskite precursor solution additive, a perovskite precursor solution and a battery.

[0008] The present invention is achieved in that: In a first aspect, the present invention provides a method for screening a perovskite precursor solution additive, comprising: Analyze the solvent and solute of the perovskite precursor base liquid, and select an additive that does not dissolve any component of the solute and is miscible with the solvent from a plurality of candidate additives as a first additive; Selecting an additive having a lower surface tension than the base liquid of the perovskite precursor liquid from the first additives as a second additive; From the second additives, an additive having a normal pressure boiling point different from that of the perovskite precursor liquid base liquid by more than 20° C. is selected as a target additive.

[0009] In an optional embodiment, the miscibility ratio of the first additive and the solvent is greater than 28%.

[0010] In an optional embodiment, the surface tension of the second additive is lower than the surface tension of the perovskite precursor base liquid by more than 1 mN / m.

[0011] In an optional embodiment, the target additive has a boiling point below 240°C at atmospheric pressure.

[0012] In an optional embodiment, the target additives include volatility-increasing additives and volatility-reducing additives, the volatility-increasing additives include at least one of lower alkanes, cycloalkanes, lower esters, halogenated aromatics, monocyclic aromatics and lower ethers; the volatility-reducing additives include at least one of polyhalogenated aromatics and glycol ester ethers.

[0013] In an optional embodiment, the volatility-enhancing additive includes at least one of methylheptane, n-pentane, cyclopentane, butyl butyrate, chlorobenzene, toluene and dipropylene glycol dimethyl ether.

[0014] In an alternative embodiment, the volatility reducing additive comprises at least one of o-dichlorobenzene, trichlorobenzene, diethylene glycol monobutyl ether and ethylene glycol carbonate.

[0015] In an optional embodiment, the volatility-enhancing additive is methylheptane; And / or, the volatility reducing additive is diethylene glycol monobutyl ether or ethylene glycol carbonate.

[0016] In a second aspect, the present invention provides a perovskite precursor solution, comprising a precursor base solution and a target additive obtained by screening the perovskite precursor additive screening method as described in any of the aforementioned embodiments, wherein the added volume of the target additive is 5-20% of the volume of the precursor base solution.

[0017] In an optional embodiment, the precursor base liquid includes a solvent system and a perovskite component, the solvent system includes at least one of ethylene glycol monomethyl ether, N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, γ-butyrolactone and acetonitrile, and the concentration of the perovskite component in the solvent system is 1-2 mol / L.

[0018] In a third aspect, the present invention provides a perovskite battery, comprising the perovskite precursor solution as described in any one of the aforementioned embodiments.

[0019] The present invention has the following beneficial effects: The screening method of the perovskite precursor liquid additive provided by the present invention is to screen a variety of additives, and the screened target additive is not only miscible with the solvent of the perovskite precursor liquid base liquid, but also does not affect the solubility of the solute. By screening out additives with a surface tension lower than that of the perovskite precursor liquid base liquid, the overall surface tension of the perovskite precursor liquid can be reduced. When the liquid with low surface tension contacts the solid surface, it can spread and wet better, thereby improving the wetting efficiency, and at the same time helping to improve the dispersion efficiency and coating performance. When the volatility of the perovskite precursor liquid base liquid is too high or too low, it will lead to problems such as insufficient crystallization time or solvent residue. In the present invention, an additive with a large difference in normal pressure boiling point is selected, and the volatility of the perovskite precursor liquid is adjusted by adding the additive, so that the volatility of the perovskite precursor liquid can be kept within a suitable range. The screening method of the perovskite precursor solution additive provided by the present invention has simple screening operation, the screened target additive does not destroy the original solute-solvent system, has strong adjustability, and does not affect the crystallization nucleation process; it can be applied to any wet process for preparing hybrid perovskite thin films, and optimizes its processing technology and operation window time. The screening method of the present invention can adjust the wettability and volatility of the hybrid perovskite solar cell precursor solution without affecting its crystallization performance, thereby improving the comprehensive performance of the precursor solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 This is a schematic diagram of the perovskite precursor solution provided in Example 1 after coating to form a film; Figure 2 This is a schematic diagram of the perovskite precursor solution provided in Comparative Example 1 after coating to form a film; Figure 3This is a schematic diagram of the perovskite precursor solution provided in Example 4 after coating to form a film; Figure 4 This is a schematic diagram of the perovskite precursor solution provided in Comparative Example 5 after coating and forming a film. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0023] The present invention provides a method for screening a perovskite precursor solution additive, which comprises the following steps: S1. Analyze the solvent and solute of the perovskite precursor base liquid, and select an additive that does not dissolve any component of the solute and is miscible with the solvent from a plurality of candidate additives as a first additive; S2, selecting an additive having a surface tension lower than that of the perovskite precursor liquid base liquid from the first additive as a second additive; S3. Select an additive from the second additives whose normal pressure boiling point differs from that of the perovskite precursor liquid base liquid by more than 20° C. as a target additive.

[0024] In the present invention, the perovskite precursor liquid base liquid added with the above-mentioned target additive is used as the perovskite precursor liquid of the present invention. By screening a variety of additives, the screened target additive is not only miscible with the solvent of the perovskite precursor liquid base liquid, but also does not affect the solubility of the solute, and by screening out additives with a surface tension lower than that of the perovskite precursor liquid base liquid, it can reduce the overall surface tension of the perovskite precursor liquid, and the liquid with low surface tension can be better spread and wetted when contacting the solid surface, thereby improving the wetting efficiency, and at the same time helping to improve the dispersion efficiency and coating performance. When the volatility of the perovskite precursor liquid base liquid is too high or too low, it will lead to problems such as insufficient crystallization time or residual solvent. In the present invention, an additive with a large difference in normal pressure boiling point is selected, and the volatility of the perovskite precursor liquid is adjusted by the addition of the additive, so that the volatility of the perovskite precursor liquid can be maintained within a suitable range.

[0025] Specifically, in the present invention, by testing the solubility of various additives to the solute, an additive that does not dissolve the solute and is miscible with the solvent is selected as the first additive. The first additive selected in the screening step can not destroy the original solute-solvent system, has strong adjustability, and does not affect the crystallization nucleation process. Among them, the miscibility ratio of the first additive and the solvent is greater than 28%, that is, the first additive needs to reach a good miscibility ratio with the solvent to be used as the first additive of the present invention, and continue the subsequent screening.

[0026] The surface tension of the second additive is lower than the surface tension of the perovskite precursor base liquid by more than 1 mN / m, and preferably the surface tension of the second additive is lower than the surface tension of the perovskite precursor base liquid by more than 3 mN / m. By selecting a surface tension that is significantly different from the perovskite precursor base liquid, the surface tension of the final perovskite precursor liquid can be better adjusted by adding the selected additive, thereby improving the wetting efficiency, dispersion efficiency and coating performance.

[0027] The atmospheric boiling point of the target additive is lower than 240°C. If the atmospheric boiling point is too high, it will be difficult to remove in the later process of coating the perovskite precursor solution into a thin film, which will lead to the problem of residual target additive.

[0028] Through the above screening method, the present invention obtains the target additive that can improve wettability and volatility, wherein the target additive is also divided into volatility-increasing additives and volatility-reducing additives according to their atmospheric boiling points.

[0029] The volatility-increasing additive includes at least one of lower alkanes, cycloalkanes, lower esters, and halogenated aromatics; preferably, the volatility-increasing additive includes but is not limited to at least one of methylheptane, n-pentane, cyclopentane, butyl butyrate, chlorobenzene, toluene, and dipropylene glycol dimethyl ether.

[0030] The volatility reducing additive includes at least one of polyhalogenated aromatic hydrocarbons and glycol ester ethers. Preferably, the volatility reducing additive includes but is not limited to at least one of o-dichlorobenzene, trichlorobenzene, diethylene glycol monobutyl ether and ethylene glycol carbonate.

[0031] The screening method of the perovskite precursor solution additive provided by the present invention has simple screening operation, the screened target additive does not destroy the original solute-solvent system, and has strong adjustability; it can be applied to any process for preparing hybrid perovskite thin films by wet method, and optimizes its processing technology and operation window time. The screening method of the present invention can adjust the wettability and volatility of the hybrid perovskite solar cell precursor solution without affecting its crystallization performance, thereby improving the comprehensive performance of the precursor solution.

[0032] In addition, the present invention also provides a perovskite precursor solution, which includes a precursor solution base solution and a target additive obtained by screening the above-mentioned perovskite precursor solution additive screening method, and the added volume of the target additive is 5-20% of the volume of the precursor solution base solution.

[0033] The precursor liquid base liquid includes a solvent system and a perovskite component, the solvent system and the perovskite component, the solvent system includes but is not limited to ethylene glycol monomethyl ether (2-ME), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), γ-butyrolactone (GBL) and acetonitrile (ACN) and other solvents, or a combination of two or more solvents, and the concentration of the perovskite component in the solvent system is 1-2 mol / L.

[0034] The perovskite component is of ABX3 type. The present invention lists some typical but non-limiting perovskite components, such as FA 0.75 Cs 0.25 Pb(I 0.8 Br 0.2 )3 and FA 0.3 MA 0.7 At least one of PbI3 and other common perovskite components on the market can also be used as the perovskite components of the present application.

[0035] In the case where the components of the precursor base liquid are different, the final target additive obtained by the above screening may be different, and the amount of addition may also vary slightly depending on the different precursor base liquids.

[0036] By adding the above-mentioned specific target additives to the precursor base liquid, the obtained precursor has good wettability, suitable volatility, good dispersion efficiency and coating performance. The present invention effectively improves the problem of poor wettability of the perovskite precursor liquid, which affects wet processing; it improves the problem that the volatility of the perovskite precursor liquid is too high / too low, resulting in insufficient crystallization time or solvent residue.

[0037] The screening method of the perovskite precursor solution additive of the present invention utilizes the principle of solvent miscibility and can be applied to any wet processing perovskite solvent system and processing method, including but not limited to spin coating, slit coating, blade coating, screen printing, inkjet printing, etc.

[0038] In addition, the present invention also provides a perovskite battery, which includes the above-mentioned perovskite precursor solution, and the perovskite battery has excellent performance.

[0039] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0040] Example 1 Based on the two-terminal silicon / perovskite stacked solar cell device, in the wide bandgap perovskite solar cell (1.67eV), when using p-type polymer materials such as PTAA, P3HT, Poly-TPD as the hole transport layer, the perovskite precursor solution uses DMF: DMSO = 4:1 (v / v) solvent system, and the perovskite component is FA 0.75 Cs0.25 Pb(I 0.8 Br 0.2 )3, concentration 1.5mol / L, film making method is wet slit coating. When preparing devices by small-area spin coating process, DMF needs to be used to rinse the polymer film layer to improve wettability. However, when using the slit coating process for large-area film making, the rinsing process cannot be performed, and other solutions need to be used to improve wettability. At the same time, when this process is used for large-area film making, it is necessary to increase the volatility of the solvent, shorten the production cycle, and reduce solvent residues.

[0041] Based on the above requirements, this embodiment provides a method for screening additives for perovskite precursor solutions, in which the solvent and solute of the perovskite precursor base solution are analyzed, wherein DMF, the main solvent that affects volatility and wettability in the perovskite base solution, is used as a screening basis.

[0042] Among them, the boiling point of DMF is 153℃, the surface tension is 25.7mN / m, and the boiling point of DMSO is 189℃, the surface tension is 43.6 mN / m. Methylheptane was selected as the target additive, among which methylheptane does not dissolve FA 0.75 Cs 0.25 Pb(I 0.8 Br 0.2 )3, and the miscibility ratio with the solvent (DMF+DMSO) is >28% v / v. It also has a relatively low boiling point of about 100°C (lower than the boiling point of the main solvent DMF by more than 10°C), and a relatively low surface tension (21.8 mN / m) (lower than the surface tension of the main solvent DMF by 3.9 mN / m).

[0043] Methylheptane is added as a target additive to the above-mentioned perovskite precursor base liquid to form a perovskite precursor liquid. The amount of methylheptane added is 20% of the volume of the perovskite precursor base liquid. The wettability and volatility of the perovskite precursor liquid are adjusted to achieve uniform coating of the perovskite film on the PTAA film substrate, thereby improving the wettability and shortening the production cycle.

[0044] Example 2 This embodiment is substantially the same as Embodiment 1, except that, in this embodiment, the amount of methylheptane added is 5% of the volume of the perovskite precursor base liquid.

[0045] Example 3 This embodiment is substantially the same as Embodiment 1, except that toluene is used as the additive in this embodiment.

[0046] Example 4 Based on single-junction perovskite solar cell devices, in narrow-bandgap perovskite solar cells, when NiOx / SAM is used as the hole transport layer, the perovskite precursor solution uses a 2-ME solvent system, and an air knife drying-assisted crystallization process is used. The perovskite component is FA 0.3 MA 0.7 PbI3, concentration 1.3M, film making method is wet slit coating. Due to its poor wettability and high solution volatility, it is easy to cause liquid bridge breakage and de-coating during the production process. In order to optimize the production process, it is necessary to increase its wettability and reduce volatility appropriately.

[0047] To meet this demand, this embodiment provides a method for screening additives for perovskite precursor solutions, in which the solvent and solute of the perovskite precursor base solution are analyzed, wherein the main solvent 2-ME in the perovskite base solution that affects volatility and wettability is used as a screening basis.

[0048] Among them, 2-ME is 2-methoxyethanol, the surface tension is 27.6 mN / m, the boiling point is 124℃, and diethylene glycol monobutyl ether is selected as the target additive. Among them, diethylene glycol monobutyl ether will not dissolve FA 0.3 MA 0.7 PbI3, and can be miscible with the perovskite precursor solution of the 2-ME system in a large proportion, and has a high boiling point (230°C, higher than 2-ME 96°C) and a low surface tension (27.4 mN / m). Using a small amount of this additive can adjust the volatility and wettability of the perovskite precursor solution to a certain extent. After solubility experiments, it does not affect the solubility of the raw materials. The limit addition ratio is 65 v / v%. When the precursor solution is mutually dissolved and doped (12% v / v doping), uniform film formation can be achieved by slit coating at a speed of 60 mm / s, widening the process time window.

[0049] Comparative Example 1 The perovskite precursor solution provided in this comparative example is the perovskite precursor base solution in Example 1, and no target additive is added in this comparative example.

[0050] Comparative Example 2 In comparison with Example 1, in order to improve the wettability alone, a solid additive lecithin (laP) is used as a surfactant to improve the wettability of the precursor solution. However, the lecithin required to achieve the goal of the precursor solution being able to wet PTAA remains in the perovskite film, causing defects and reducing the performance of the solar cell device.

[0051] Comparative Example 3 This comparative example is basically the same as Example 1, except that the additive used in this comparative example is trifluoroethanol, which has a normal pressure boiling point of 77-80°C and a surface tension of 16.5 mN / m. The additive satisfies the requirement of selecting a surface tension lower than that of the perovskite precursor base liquid and a normal pressure boiling point that differs from that of the perovskite precursor base liquid by more than 20°C, but does not satisfy the requirement of not dissolving any component of the solute in the perovskite precursor base liquid.

[0052] Comparative Example 4 This comparative example is basically the same as Example 1, except that the additive used in this comparative example is chlorobenzene, which has a normal pressure boiling point of 132°C and a surface tension of 34 mN / m. The additive satisfies the requirements that it does not dissolve any component of the solute in the perovskite precursor base liquid and the solvents are miscible with each other, and the normal pressure boiling point differs from the perovskite precursor base liquid by more than 20°C, but does not satisfy the requirement that the surface tension is lower than that of the perovskite precursor base liquid.

[0053] Comparative Example 5 The perovskite precursor solution provided in this comparative example is the perovskite precursor base solution in Example 4, and no target additive is added in this comparative example.

[0054] Experimental example The precursor liquids obtained in the above Examples 1-4 and Comparative Examples 1-5 were respectively tested after coating, wherein Examples 1-3 and Comparative Examples 1-4 used M6 size velvet silicon wafers (166×166 cm) as substrates, coated the perovskite precursor liquid on the PTAA hole transport layer, and heated to form a film. Example 4 and Comparative Example 5 used M6 size glass (166×166 cm) as substrates, coated the perovskite precursor liquid on the NiOx / SAM hole transport layer at a speed of 60 mm / s to form a film.

[0055] After coating, its wettability, volatility, coating speed upper limit and device conversion rate are tested. The testing methods include observing the coverage rate for wettability, observing the film-forming time window and flash evaporation time requirement for volatility, and the upper limit of walking time is the fastest coating speed under the premise of ensuring efficiency. The device conversion rate is the tester efficiency after the front substrate is made into a device. Please refer to the table below for the test results.

[0056]

[0057] See also Figure 1 and Figure 2, it can be seen that the perovskite precursor added with the additive selected by the present invention in Example 1 has good infiltration and complete film formation, and the human shadow can be seen in the mirror reflection. When no additive is used in Comparative Example 1, the perovskite film is not completely covered due to poor wettability. In Comparative Example 2, solid additive lecithin is used as a surfactant. Although it can improve the wettability of the precursor solution, it has poor volatility and needs to extend the flash evaporation time. At the same time, its device conversion rate is significantly lower than that of Comparative Example 1. In Comparative Example 3, the additive used is trifluoroethanol, which does not meet the requirement of not dissolving any component of the solute in the base liquid of the perovskite precursor solution, resulting in the crystallization nucleation process being affected, and the device conversion rate is significantly lower than that of Example 1. In Comparative Example 4, the additive used is chlorobenzene, which has a surface tension of 34 mN / m, which is higher than the surface tension of the base liquid of the perovskite precursor solution, resulting in poor wettability, a large area of ​​about 2 cm shrinkage at the edge of the substrate, and serious leakage.

[0058] Furthermore, in Example 2, the amount of methylheptane added in Example 1 is reduced, resulting in slightly worse wettability than in Example 1, but still able to meet the requirements of film formation and flash evaporation, and able to obtain a higher coating speed and device conversion rate. In Example 3, toluene is selected as an additive, which still has good wettability, can meet the requirements of film formation and flash evaporation, and can obtain a higher coating speed and device conversion rate.

[0059] See also Figure 3 and Figure 4 It can be seen that the perovskite precursor in Example 4 with the additive selected by the present invention has good infiltration and complete film formation, and a human shadow can be seen in the mirror reflection, while in Comparative Example 5, when no additive is used, the front end of the perovskite film is de-coated.

[0060] It can be seen from the above table that the use of appropriate solvent additives has a significant impact on the production process and device efficiency of large-area perovskite cell devices.

[0061] In summary, the screening method of the perovskite precursor solution additive provided by the present invention is to screen a variety of additives, and the screened target additive is not only miscible with the solvent of the perovskite precursor solution base liquid, but also does not affect the solubility of the solute, and the surface tension is lower than the perovskite precursor solution base liquid. The additive can reduce the overall surface tension of the perovskite precursor solution, and the liquid with low surface tension can spread and wet better when contacting the solid surface, thereby improving the wetting rate, and at the same time helping to improve the dispersion efficiency and coating performance. When the volatility of the perovskite precursor solution base liquid is too high or too low, it will lead to problems such as insufficient crystallization time or solvent residue. In the present invention, an additive with a large difference in atmospheric boiling point is selected, and the volatility of the perovskite precursor solution is adjusted by adding the additive, so that the volatility of the perovskite precursor solution can be kept within a suitable range. The screening method of the perovskite precursor solution additive provided by the present invention has simple screening operation, the screened target additive does not destroy the original solute-solvent system, has strong adjustability, and does not affect the crystallization nucleation process; it can be applied to any wet process for preparing hybrid perovskite thin films, and optimizes its processing technology and operation window time. The screening method of the present invention can adjust the wettability and volatility of the hybrid perovskite solar cell precursor solution without affecting its crystallization performance, thereby improving the comprehensive performance of the precursor solution.

[0062] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for screening a perovskite precursor solution additive, characterized in that: It includes: Analyze the solvent and solute of the perovskite precursor base liquid, and select an additive that does not dissolve any component of the solute and is miscible with the solvent from a plurality of candidate additives as a first additive; Selecting an additive having a lower surface tension than the base liquid of the perovskite precursor liquid from the first additives as a second additive; From the second additives, an additive having a normal pressure boiling point different from that of the perovskite precursor liquid base liquid by more than 20° C. is selected as a target additive.

2. The method for screening perovskite precursor solution additives according to claim 1, characterized in that: The miscibility ratio of the first additive and the solvent is greater than 28%.

3. The method for screening perovskite precursor solution additives according to claim 1, characterized in that: The surface tension of the second additive is lower than the surface tension of the perovskite precursor base solution by more than 1 mN / m.

4. The method for screening perovskite precursor solution additives according to claim 1, characterized in that: The target additive has a normal pressure boiling point lower than 240°C.

5. The method for screening perovskite precursor solution additives according to claim 1, characterized in that: The target additives include volatility-increasing additives and volatility-reducing additives, wherein the volatility-increasing additives include at least one of lower alkanes, cycloalkanes, lower esters, halogenated aromatics, monocyclic aromatics and lower ethers; and the volatility-reducing additives include at least one of polyhalogenated aromatics and glycol ester ethers.

6. The method for screening perovskite precursor solution additives according to claim 5, characterized in that: The volatility-enhancing additive comprises at least one of methyl heptane, n-pentane, cyclopentane, butyl butyrate, chlorobenzene, toluene and dipropylene glycol dimethyl ether; And / or, the volatility reducing additive includes at least one of o-dichlorobenzene, trichlorobenzene, diethylene glycol monobutyl ether and ethylene glycol carbonate.

7. The method for screening perovskite precursor solution additives according to claim 6, characterized in that: The volatility-enhancing additive is methylheptane; And / or, the volatility reducing additive is diethylene glycol monobutyl ether or ethylene glycol carbonate.

8. A perovskite precursor solution, characterized in that: It comprises a precursor solution and a target additive obtained by screening according to the method for screening perovskite precursor solution additives as described in any one of claims 1 to 7, wherein the added volume of the target additive is 5-20% of the volume of the precursor solution base solution.

9. The perovskite precursor solution according to claim 8, characterized in that: The precursor base liquid includes a solvent system and a perovskite component, the solvent system includes at least one of ethylene glycol monomethyl ether, N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, γ-butyrolactone and acetonitrile, and the concentration of the perovskite component in the solvent system is 1-2 mol / L.

10. A perovskite battery, characterized in that: It comprises the perovskite precursor solution as described in any one of claims 8 to 9.

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