Perovskite solar cell based on neutral buffering agent and preparation method thereof

Abstract

The invention relates to a neutral buffer agent-based perovskite solar cell and a preparation method thereof, the perovskite solar cell comprises a transparent conductive substrate layer, a perovskite light absorption layer, an electron transport layer, an interface modification layer and an electrode layer from bottom to top, and the perovskite light absorption layer contains a neutral buffer agent; the structural general formula of the neutral buffering agent is X.Y, X is self-assembled monomolecular organic acid, and Y is reductive organic amine. The neutral buffering agent is adopted to regulate perovskite crystallization and passivate a buried interface, a chelate is formed through hydrogen-bond interaction to inhibit solvent volatilization and delay the crystallization rate, the preparation window period is widened, and large-area perovskite thin film homogenization preparation is facilitated. The high solubility of the neutral buffer agent in the precursor solution can induce the neutral buffer agent to spontaneously gather at the bottom interface of the perovskite thin film, so that the hole concentration is improved, the defect density is reduced, the carrier lifetime of the perovskite thin film is greatly prolonged, and an important reference is provided for industrialization of perovskite solar cells.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and particularly relates to a perovskite solar cell based on a neutral buffer and a preparation method thereof. Background Art

[0002] In recent years, organic lead halide perovskite materials have become the focus of research. This material shows application potential in fields such as light-emitting diodes and lasers, and particularly the breakthrough progress in the field of photovoltaic technology is more remarkable. The currently certified photoelectric conversion efficiency has reached 27%. Lead halide perovskite materials not only have high-efficiency light absorption ability, but also can generate free carriers and achieve charge transport. One of its core advantages is that high-quality polycrystalline thin films can be prepared through various solution deposition processes. Although the device efficiency can be significantly improved by finely tuning the perovskite composition, deposition process, and solvent mixing ratio, existing research mainly focuses on the optimization of empirical parameters, and there is still a lack of systematic research on the chemical properties of the precursor solution and its influence on the crystallization process.

[0003] Introducing self-assembled monomolecular organic acid additives into the perovskite precursor solution is one of the effective means to realize perovskite cells without hole transport materials. The introduction of acidic additives reduces the pH value of the perovskite precursor solution, significantly changes the chemical environment of the solution, accelerates the aging of the perovskite precursor solution, reduces the crystallinity and carrier transport performance of the perovskite thin film, seriously affects the stability and consistency of the perovskite cell preparation process, and hinders the industrialization process of perovskite solar cells. Summary of the Invention

[0004] The purpose of the present invention is to avoid the deficiencies of the prior art, and provide a perovskite solar cell based on a neutral buffer and a preparation method thereof. By introducing a neutral buffer material into the perovskite precursor solution, the acid-base balance of the precursor solution is achieved, the chemical environment of the perovskite precursor solution is not changed, and the chemical degradation of the precursor solution is inhibited. In addition, there is an interaction between the neutral buffer and the surface of the perovskite grains, and a strong bonding interaction is formed between the acid root ions and the uncoordinated Pb 2+ at the grain boundaries, reducing the electron density around Pb 2+ , thus resulting in a decrease in the electron donor density of the perovskite, increasing the hole concentration in the perovskite, and effectively improving the hole conduction of the bottom perovskite.

[0005] According to the first aspect of the embodiments of the present application, a perovskite solar cell based on a neutral buffer is provided. The perovskite solar cell includes a transparent conductive substrate layer, a perovskite light-absorbing layer, an electron transport layer, an interface modification layer, and an electrode layer from bottom to top, wherein the perovskite light-absorbing layer contains a neutral buffer;

[0006] The structural general formula of the neutral buffer is X·Y, where X is a self-assembled monolayer organic acid, including one or more of carbazole-core organic acids, triphenylamine-core organic acids, and acridine-core organic acids. The corresponding chemical structural formulas are as follows:

[0007]

[0008] Among them, R1 are each independently one or more combinations of hydrogen, halogen groups (F, Cl, Br, I), methyl, methoxy, ethyl, ethoxy, trifluoromethyl, n-propyl, n-propoxy, isopropyl, isopropoxy, n-butyl, n-butoxy, isobutyl, isobutoxy, sec-butyl, sec-butoxy, tert-butyl, tert-butoxy, phenyl, benzyl, phenethyl, phenoxy, phenethyl, benzyloxy, phenethoxy; R2 are each independently one or more combinations of hydrogen, halogen groups (F, Cl, Br, I), methyl, methoxy, ethyl, ethoxy, trifluoromethyl, n-propyl, n-propoxy, isopropyl, isopropoxy, n-butyl, n-butoxy, isobutyl, isobutoxy, sec-butyl, sec-butoxy, tert-butyl, tert-butoxy, phenyl, benzyl, phenethyl, phenoxy, phenethyl, benzyloxy, phenethoxy; R3 is one or more combinations of methylene, methylidene, phenylene, benzylidene, phenethylidene, styryl, vinyl; R4 is one of carboxyl, phosphonic acid group, sulfonic acid group, boric acid group, cyano-carboxyl group, cyano-phosphonic acid group, cyano-sulfonic acid group, cyano-boric acid group; X is one of ether bond, thioether bond, methylene, methylidene; n is 1, 2, 3, 4, 5…;

[0009] Y is a reducing organic amine, including organic amine compounds containing one or more combinations of hydrazino group, acylhydrazino group, n C═C double bonds (n = 2, 3, 4…), phenolic hydroxyl group, aldehyde group, mercapto group, ferrocenyl group.

[0010] Furthermore, the transparent conductive substrate layer is made of FTO glass, ITO glass, ITO / PET, ITO / PEN or ITO / PI.

[0011] Furthermore, the structural general formula of the perovskite light-absorbing layer is ABX3, and the thickness is 100 - 2000 nm, where A is Cs + 、MA + or FA + , B is Pb 2+ , Sn 2+ or Ge 2+ , and X is I - , Br - or Cl - .

[0012] Furthermore, the electron transport layer is fullerene and its derivatives, and the thickness is 1 - 100 nm.

[0013] Further, the interface modification layer is composed of bathocuproine, tin oxide, zinc oxide, yttrium oxide, cerium oxide, titanium oxide or niobium oxide, and has a thickness of 1 to 100 nm.

[0014] Further, the electrode layer is made of Cu, Ag, Au, Mo, ITO, IZO or AZO, and has a thickness of 10 to 10,000 nm.

[0015] According to a second aspect of the embodiments of the present application, there is provided a method for preparing a perovskite solar cell based on a neutral buffer as described in the first aspect, including:

[0016] (1) Synthesize a neutral buffer;

[0017] (2) Dissolve the perovskite powder in an organic solvent, stir to clarify to form a perovskite precursor solution, add a neutral buffer, and dissolve completely to obtain a perovskite precursor solution containing a neutral buffer. Coat or print the perovskite precursor solution containing a neutral buffer on a clean transparent conductive substrate and perform heat treatment to obtain a perovskite light-absorbing layer;

[0018] (3) Sequentially deposit an electron transport layer, an interface modification layer and an electrode layer on the perovskite light-absorbing layer to obtain a perovskite solar cell based on a neutral buffer.

[0019] Further, in step (2), the organic solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 2-methoxyethanol, and acetonitrile, preferably 2-methoxyethanol and N-methylpyrrolidone (volume ratio 9:1), the concentration of the perovskite precursor solution is 0.1 to 3 mol / L, preferably 1.25 mol / L, the concentration of the neutral buffer in the perovskite precursor solution containing a neutral buffer is 0.001 to 50 mg / mL, preferably 5 mg / mL, the heat treatment temperature is 30 to 300 °C, and the time is 5 to 120 minutes, preferably 110 °C for 30 minutes.

[0020] Further, in step (3), the deposition method of the electron transport layer is evaporation, and the deposition method of the interface modification layer is selected from evaporation, sputtering, reactive plasma deposition, chemical vapor deposition, coating, and printing, preferably reactive plasma deposition. The deposition method of the electrode layer is selected from evaporation, sputtering, chemical vapor deposition, coating, and printing, preferably sputtering deposition.

[0021] The technical solutions provided by the present application may include the following beneficial effects:

[0022] 1. The present invention uses a neutral buffer to improve the long-term storage stability of the perovskite precursor solution. The reducing organic amine can effectively neutralize the acidity and alkalinity of the perovskite precursor solution while removing the elemental iodine generated in the perovskite active layer, inhibiting the self-accelerating degradation process of perovskite, thereby significantly improving the long-term operational stability of the perovskite solar cell. In addition, the lone pair electrons on the sulfur atom in the buffer can supply electrons to the unsaturated Pb at the bottom of the perovskite, 2+ forming a coordination bond. The strong interaction will enhance the binding between the molecule and the perovskite surface, which is helpful for the preparation of large-area high-quality perovskite thin films.

[0023] 2. The interaction between the neutral buffer adopted in the present invention and the perovskite can optimize the interfacial energy level alignment, improve the charge transport ability of the device, form a high built-in electric field at the perovskite bottom interface, which is helpful for the separation of electrons and holes, enhancing the separation and transport efficiency of carriers, and thus improving the optoelectronic performance of the perovskite solar cell.

[0024] 3. The organic acid anchoring group in the neutral buffer adopted in the present invention can effectively passivate the surface defects of the perovskite, alleviate the interfacial charge recombination, and promote the in-plane growth of perovskite grains, thereby enhancing the photothermal stability of the perovskite solar cell.

[0025] 4. The perovskite solar cell regulated by the neutral buffer adopted in the present invention has the advantages of high photoelectric conversion efficiency, good long-term working stability, high preparation repeatability, etc.

[0026] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with this application, and are used together with the specification to explain the principles of this application.

[0028] Figure 1 is a schematic structural diagram of the perovskite solar cell based on oxalylhydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonate of the present invention;

[0029] Figure 2 is a graph showing the change in absorbance intensity of the perovskite precursor solution containing oxalylhydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonate of the present invention placed in air for different times;

[0030] Figure 3 is a graph showing the relationship between the efficiency of the perovskite solar cell containing oxalylhydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonate of the present invention and the time the perovskite precursor solution is placed in air. Detailed implementation manners

[0031] Here, exemplary embodiments will be described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present application.

[0032] The terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "the", and "said" used in the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0033] It should be understood that although the terms first, second, third, etc. may be used in the present application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0034] The perovskite solar cell provided by the present invention includes, from bottom to top, a transparent conductive substrate layer, a perovskite light-absorbing layer, an electron transport layer, an interface modification layer, and an electrode layer, wherein the perovskite light-absorbing layer contains a neutral buffer. The present invention uses a neutral buffer to achieve crystallization regulation and buried interface passivation of perovskite, can form hydrogen bond interactions with perovskite organic cations and solvents, and form chelates with metal halides in the perovskite precursor, inhibit solvent volatilization during the perovskite crystallization process and delay the perovskite crystallization rate, greatly extending the preparation window time for the formation of the perovskite thin film, and contributing to the uniform preparation of a large-area perovskite thin film. The high solubility of the neutral buffer in the precursor solution can induce it to spontaneously aggregate at the bottom interface of the perovskite thin film, resulting in an increase in the perovskite hole concentration at the buried interface, reducing the defect density at the bottom interface, and greatly improving the carrier lifetime of the perovskite thin film.

[0035] To solve the above problems, the present invention provides the following specific implementation manners.

[0036] Embodiment:

[0037] As Figure 1 shown, a preparation method of a perovskite solar cell based on a neutral buffer includes the following steps:

[0038] (1) Weigh 118.1 mg (1 mmol) of oxalohydrazide in 10 mL of absolute ethanol, and weigh 493.15 mg (1 mmol) of 4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonic acid and dissolve it in 10 mL of absolute ethanol. Slowly drip the ethanol solution of 4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonic acid into the continuously stirred ethanol solution of oxalohydrazide. Keep the reaction temperature at 0 °C during the reaction process. After the dripping is completed, continue stirring for 40 min, and then perform rotary evaporation to obtain the crude product of oxalohydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonate. Finally, wash the crude product four times with ethyl acetate and diethyl ether in sequence to obtain pure oxalohydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonate (446 mg, yield about 73%). After vacuum drying for 12 h, it is reserved for use;

[0039] (2) Ultrasonically clean the FTO glass with glass cleaner, ultrapure water and alcohol in sequence. After cleaning, dry it to obtain a clean FTO glass substrate;

[0040] (3) First, weigh CsI, MAI, FAI, PbI2 (molar ratio 0.05:0.15:0.8:1.08) powders and dissolve them in a mixed solvent of 2-methoxyethanol and N-methylpyrrolidone (volume ratio 9:1). After stirring until clear, a 1.25 mol / L perovskite precursor solution is obtained. Subsequently, weigh 5 mg of oxalohydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonate and add it to 1 mL of the perovskite precursor solution. After stirring until completely dissolved, a perovskite precursor solution containing oxalohydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonate is obtained; Spin-coat the perovskite precursor solution containing oxalohydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonate on the clean FTO glass substrate. Heat-treat the spin-coated perovskite wet film at 110 °C for 30 min to obtain a perovskite light-absorbing layer with a thickness of 500 nm;

[0041] (4) Evaporate a 30-nm-thick C60 electron transport layer, deposit a 20-nm-thick tin oxide interface modification layer by reactive plasma deposition, and sputter-deposit a 500-nm-thick IZO electrode layer on the perovskite light-absorbing layer in sequence to obtain a perovskite solar cell based on oxalohydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonate neutral buffer.

[0042] Comparative Example 1:

[0043] A perovskite solar cell without a neutral buffer and its preparation method, including the following steps:

[0044] (1) The FTO glass was ultrasonically cleaned successively with glass cleaning agent, ultrapure water and alcohol, and dried after cleaning to obtain a clean FTO glass substrate.

[0045] (2) First, CsI, MAI, FAI, PbI2 (molar ratio 0.05:0.15:0.8:1.08) powders were weighed and dissolved in a mixed solvent of 2-methoxyethanol and N-methylpyrrolidone (volume ratio 9:1). After stirring and clarification, a 1.25 mol / L perovskite precursor solution was obtained. The perovskite precursor solution was slit-coated on the clean FTO glass substrate, and the coated perovskite wet film was heat-treated at 110 °C for 30 min to obtain a 500 nm thick perovskite light-absorbing layer.

[0046] (3) A 30 nm thick C60 electron transport layer, a 20 nm thick tin oxide interface modification layer deposited by reactive plasma, and a 500 nm thick IZO electrode layer were successively evaporated on the perovskite light-absorbing layer to obtain a perovskite solar cell without a neutral buffer.

[0047] Comparative Example 2:

[0048] A perovskite solar cell based on self-assembled monomolecular organic acid and its preparation method, comprising the following steps:

[0049] (1) The FTO glass was ultrasonically cleaned successively with glass cleaning agent, ultrapure water and alcohol, and dried after cleaning to obtain a clean FTO glass substrate.

[0050] (2) First, CsI, MAI, FAI, PbI2 (molar ratio 0.05:0.15:0.8:1.08) powders were weighed and dissolved in a mixed solvent of 2-methoxyethanol and N-methylpyrrolidone (volume ratio 9:1). After stirring and clarification, a 1.25 mol / L perovskite precursor solution was obtained. Subsequently, 5 mg of 4-(3,7-dibromo-10H-benzo[h]quinolin-10-yl)butylphosphonic acid was weighed and added to 1 mL of the perovskite precursor solution. After stirring and complete dissolution, a perovskite precursor solution containing 4-(3,7-dibromo-10H-benzo[h]quinolin-10-yl)butylphosphonic acid was obtained. The perovskite precursor solution containing 4-(3,7-dibromo-10H-benzo[h]quinolin-10-yl)butylphosphonic acid was slit-coated on the clean FTO glass substrate, and the coated perovskite wet film was heat-treated at 110 °C for 30 min to obtain a 500 nm thick perovskite light-absorbing layer.

[0051] (3) A perovskite solar cell based on 4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonic acid is obtained by sequentially evaporating a 30-nm-thick C60 electron transport layer, depositing a 20-nm-thick tin oxide interface modification layer by reactive plasma deposition, and sputtering a 500-nm-thick IZO electrode layer on the perovskite light-absorbing layer.

[0052] Comparative Example 3:

[0053] A perovskite solar cell based on neutral buffer interface modification and its preparation method include the following steps:

[0054] (1) Weigh 118.1 mg (1 mmol) of oxalohydrazide in 10 mL of absolute ethanol, and weigh 493.15 mg (1 mmol) of 4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonic acid and dissolve it in 10 mL of absolute ethanol. Slowly drop the ethanol solution of 4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonic acid into the continuously stirred ethanol solution of oxalohydrazide. Keep the reaction temperature at zero during the reaction process. After the dropping is completed, continue stirring for 40 min, and then rotary evaporate to obtain the crude product of oxalohydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonate. Finally, wash the crude product four times with ethyl acetate and diethyl ether in turn to obtain pure oxalohydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonate (446 mg, yield about 73%). After vacuum drying for 12 h, it is reserved for use.

[0055] (2) Ultrasonically clean the FTO glass with a glass cleaner, ultrapure water, and alcohol in sequence. After cleaning, dry it to obtain a clean FTO glass substrate. Spin-coat a 2 mg / mL ethanol solution of oxalohydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonate on the clean FTO glass substrate. After coating, heat-treat it at 100 °C for 5 min to obtain a 3-nm-thick oxalohydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonate layer.

[0056] (3) Weigh CsI, MAI, FAI, and PbI2 powders (molar ratio 0.05:0.15:0.8:1.08) and dissolve them in a mixed solvent of 2-methoxyethanol and N-methylpyrrolidone (volume ratio 9:1). After stirring and clarification, obtain a 1.25 mol / L perovskite precursor solution. Spin-coat the perovskite precursor solution on the substrate covered with the oxalohydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butylphosphonate layer. Heat-treat the wet perovskite film at 110 °C for 30 min to obtain a 500-nm-thick perovskite light-absorbing layer.

[0057] (4) A C60 electron transport layer with a thickness of 30 nm, an indium tin oxide interface modification layer with a thickness of 20 nm by reactive plasma deposition, and an IZO electrode layer with a thickness of 500 nm by sputtering deposition are sequentially evaporated on the perovskite light-absorbing layer, thereby obtaining a perovskite solar cell based on the interface modification of oxalylhydrazide·4-(3,7-dibromo-10H-benzo[b]thiazin-10-yl)butylphosphonate.

[0058] As shown in Table 1, the perovskite solar cell prepared using oxalylhydrazide·4-(3,7-dibromo-10H-benzo[b]thiazin-10-yl)butylphosphonate as a neutral buffer has a photoelectric conversion efficiency of 26.21%, and the efficiency of the cell only decays by 3.7% after 1000 hours of maximum power point tracking. The device efficiency and stability are far superior to those of other comparative devices, indicating that adding oxalylhydrazide·4-(3,7-dibromo-10H-benzo[b]thiazin-10-yl)butylphosphonate to the perovskite precursor solution can improve the crystallization quality of the perovskite thin film, optimize the energy band structure of the buried interface, eliminate the charge transport barrier, enhance the charge transport rate, and achieve a perovskite battery with both high efficiency and high stability.

[0059] Table 1. Performance parameter table of the products in the examples and comparative examples

[0060]

[0061] The perovskite precursor solutions containing oxalylhydrazide·4-(3,7-dibromo-10H-benzo[b]thiazin-10-yl)butylphosphonate and 4-(3,7-dibromo-10H-benzo[b]thiazin-10-yl)butylphosphonic acid are placed in the air for different times. The absorption edge wavelengths of the two perovskite precursor solutions placed for different times are measured, and perovskite solar cells are respectively prepared based on the two perovskite precursor solutions placed for different times. As Figure 2 shown, compared with the perovskite precursor solution containing 4-(3,7-dibromo-10H-benzo[b]thiazin-10-yl)butylphosphonic acid, the concentration of iodine in the perovskite precursor solution containing oxalylhydrazide·4-(3,7-dibromo-10H-benzo[b]thiazin-10-yl)butylphosphonate hardly increases after being placed in the air for 30 days, indicating that the addition of oxalylhydrazide·5-phenyl-2,4-pentadienoate can significantly improve the long-term stability of the perovskite precursor solution and greatly inhibit the aging degradation of the perovskite precursor solution; as Figure 3 shown, based on the perovskite precursor solutions containing oxalylhydrazide·4-(3,7-dibromo-10H-benzo[b]thiazin-10-yl)butylphosphonate placed for different times, the performance of the prepared perovskite solar cells basically remains unchanged, which also confirms that oxalylhydrazide·4-(3,7-dibromo-10H-benzo[b]thiazin-10-yl)butylphosphonate can effectively maintain the acid-base balance of the perovskite precursor solution and eliminate the reduction of perovskite battery performance caused by the deterioration of the precursor solution.

[0062] Therefore, in combination with Figure 2 - Figure 3 As shown, the device prepared with the perovskite precursor solution using oxalyl dihydrazide·4-(3,7-dibromo-10H-benzo[b][1,4]thiazin-10-yl)butyl phosphonate neutral buffer has high performance consistency, greatly extends the service life of the perovskite precursor solution, significantly improves the photoelectric conversion efficiency and stability of the perovskite solar cell, and helps to batch-produce large-area perovskite cells.

[0063] The above are only the preferred experimental examples of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A perovskite solar cell based on a neutral buffer, characterized in that, The perovskite solar cell from bottom to top includes a transparent conductive substrate layer, a perovskite light-absorbing layer, an electron transport layer, an interface modification layer, and an electrode layer, wherein the perovskite light-absorbing layer contains a neutral buffer. The structural general formula of the neutral buffer is X·Y, where X is a self-assembled monomolecular organic acid, including one or more of carbazole nucleus organic acids, triphenylamine nucleus organic acids, acridine nucleus organic acids, and Y is a reducing organic amine, including organic amine compounds containing one or more combined groups of hydrazine group, acylhydrazine group, n C═C double bonds, phenolic hydroxyl group, aldehyde group, mercapto group, ferrocenyl group.

2. The perovskite solar cell based on a neutral buffer as claimed in claim 1, wherein, The transparent conductive substrate layer uses FTO glass, ITO glass, ITO / PET, ITO / PEN, or ITO / PI.

3. The perovskite solar cell based on a neutral buffer as claimed in claim 1, wherein The structural general formula of the perovskite light-absorbing layer is ABX3, and the thickness is 100 to 2000 nm, where A is Cs + , MA + or FA + , B is Pb 2+ , Sn 2+ or Ge 2+ , X is I - , Br - or Cl - .

4. The perovskite solar cell based on a neutral buffer as claimed in claim 1, wherein The electron transport layer is fullerene and its derivatives, with a thickness of 1 - 100 nm.

5. The perovskite solar cell based on a neutral buffer as claimed in claim 1, wherein The interface modification layer uses bathocuproine, tin oxide, zinc oxide, yttrium oxide, cerium oxide, titanium oxide, or niobium oxide, with a thickness of 1 - 100 nm.

6. The perovskite solar cell based on a neutral buffer as claimed in claim 1, wherein, The electrode layer is Cu, Ag, Au, Mo, ITO, IZO, or AZO, with a thickness of 10 - 10,000 nm.

7. The preparation method of the perovskite solar cell based on a neutral buffer as described in any one of claims 1-6, characterized in that, It includes: (1) Synthesize the neutral buffer; (2) Dissolve the perovskite powder in an organic solvent, stir to clarify to form a perovskite precursor solution, add the neutral buffer, and dissolve completely to obtain a perovskite precursor solution containing the neutral buffer. Coating or printing the perovskite precursor solution containing the neutral buffer on a clean transparent conductive substrate and performing heat treatment to obtain the perovskite light-absorbing layer; (3) Sequentially deposit the electron transport layer, the interface modification layer, and the electrode layer on the perovskite light-absorbing layer to obtain a perovskite solar cell based on the neutral buffer.

8. The preparation method of the perovskite solar cell based on a neutral buffer as claimed in claim 7, wherein, In step (2), the organic solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 2-methoxyethanol, and acetonitrile. The concentration of the perovskite precursor solution is 0.1 - 3 mol / L, and the concentration of the neutral buffer in the perovskite precursor solution containing the neutral buffer is 0.001 - 50 mg / mL. The heat treatment temperature is 30 - 300 °C, and the time is 5 - 120 minutes.

9. The preparation method of the perovskite solar cell based on a neutral buffer as claimed in claim 7, wherein, In step (3), the deposition method of the electron transport layer is evaporation coating, and the deposition method of the interface modification layer is selected from evaporation coating, sputtering, reactive plasma deposition, chemical vapor deposition, coating, and printing. The deposition method of the electrode layer is selected from evaporation coating, sputtering, chemical vapor deposition, coating, and printing.

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