Perovskite precursor solution, perovskite active layer and preparation method thereof

Abstract

The application provides a perovskite precursor solution, a perovskite active layer and a preparation method thereof. The perovskite precursor solution comprises a perovskite mixed solution and chlorobenzene with at least one substituent group, and the boiling point of the chlorobenzene with at least one substituent group is lower than that of the perovskite mixed solution. In the subsequent process, the defects of the perovskite precursor film formed according to the perovskite precursor solution can be repaired in the process of forming the perovskite active layer by using the perovskite precursor solution, and the film forming quality in the subsequent formation of the perovskite active layer according to the perovskite precursor solution can be improved, so that the short-circuit current density is significantly improved, and the perovskite solar energy conversion efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of perovskite solar cell technology, and more specifically, to a perovskite precursor solution, a perovskite active layer, and a method for preparing the same. Background Technology

[0002] Since its initial report in 2009, perovskite solar cells have experienced rapid development over the past decade, with the reported energy conversion efficiency of single-junction cells in the laboratory increasing from the initial 3.8% to the current certified 25.7%. Among them, inverted perovskite solar cells have gained widespread attention due to their advantages such as high energy conversion efficiency, negligible hysteresis effect, low fabrication cost, and suitability as the top cell in tandem solar cells.

[0003] However, charge transport barriers between different interfaces and defects at grain boundaries remain major factors hindering performance improvement in inverted perovskite solar cell devices. Current strategies for improving device performance include composition engineering, interface engineering, and additive engineering. These strategies can enhance the light absorption of the photoactive layer, address energy level matching issues between different interfaces, or passivate various defects in perovskite films caused by rapid crystal growth during solution processing. However, since the efficiency of perovskite solar cells depends on the product of short-circuit current density, open-circuit voltage, and fill factor, and the short-circuit current density is primarily determined by the light absorption range and intensity of the perovskite material, which in turn is determined by the band gap, it is difficult to significantly improve the short-circuit current density by optimizing the quality of the perovskite film. Summary of the Invention

[0004] The main objective of this invention is to provide a perovskite precursor solution, a perovskite active layer, and a method for preparing the same, in order to solve the problem of low battery efficiency caused by low short-circuit current density in the prior art.

[0005] To achieve the above objectives, according to one embodiment of the present invention, a perovskite precursor solution is provided, the perovskite precursor solution comprising a perovskite mixed solution and chlorobenzene having at least one substituent, wherein the boiling point of the chlorobenzene having at least one substituent is lower than the boiling point of the perovskite mixed solution.

[0006] Furthermore, the substituent includes any one of halogen, C1-C20 alkyl and C1-C20 alkoxy groups, and preferably, the substituent is selected from any one of fluorine, C1-C4 alkyl and C1-C4 alkoxy groups.

[0007] Furthermore, the doping percentage of chlorobenzene having at least one substituent in the perovskite mixed solution is 0.5% to 10%.

[0008] Furthermore, chlorobenzene having at least one substituent includes any one of pentafluorochlorobenzene, p-methylchlorobenzene, and p-methoxychlorobenzene.

[0009] Furthermore, the perovskite mixed solution includes lead dihalide, ammonium methyl iodide, dimethylamide, and dimethyl sulfoxide.

[0010] To achieve the above objectives, according to another embodiment of the present invention, a method for preparing the above-mentioned perovskite precursor solution is provided, comprising the following steps: mixing a perovskite precursor material and an organic solvent to obtain a perovskite mixed solution; and doping a chlorobenzene having at least one substituent into the above-mentioned perovskite mixed solution to form a perovskite precursor solution.

[0011] Furthermore, the content of chlorobenzene with at least one substituent in the perovskite mixed solution is 10 μL / mL to 100 μL / mL.

[0012] To achieve the above objectives, according to another embodiment of the present invention, a method for preparing a perovskite active layer is provided, comprising the following steps: spin-coating a perovskite precursor solution onto a substrate, wherein the perovskite precursor solution is the perovskite precursor solution in one embodiment above, or the perovskite precursor solution is prepared by the preparation method in another embodiment above; extracting the perovskite precursor solution using an antisolvent method during the spin-coating process; and heat-treating the extracted perovskite precursor solution to form a perovskite active layer.

[0013] Furthermore, in the step of extracting the perovskite precursor solution, before a transparent intermediate film is formed in the perovskite precursor solution on the substrate, a chlorobenzene solution is added dropwise to the perovskite precursor solution on the substrate for extraction.

[0014] Furthermore, in the step of spin-coating the perovskite precursor solution, the spin-coating rate is determined based on the thickness of the perovskite active layer.

[0015] To achieve the above objectives, according to another embodiment of the present invention, a perovskite active layer is provided, which is prepared by the preparation method according to one embodiment of the present invention.

[0016] To achieve the above objectives, according to another embodiment of the present invention, a perovskite solar cell is provided, comprising: a transparent conductive layer having a first surface; a hole transport layer disposed in contact with the first surface; a perovskite active layer as in one embodiment of the present invention, disposed on the side of the hole transport layer away from the transparent conductive layer; an electron transport layer disposed on the side of the perovskite active layer away from the hole transport layer; and an electrode layer disposed on the side of the electron transport layer away from the perovskite active layer.

[0017] Furthermore, the perovskite solar cell also includes: a cathode buffer layer, which is disposed on the side of the electron transport layer away from the perovskite active layer, and an electrode layer is disposed on the side of the cathode buffer layer away from the electron transport layer.

[0018] The present invention provides a perovskite precursor solution by doping a perovskite mixed solution with chlorobenzene having at least one substituent and a low boiling point. Since the boiling point of chlorobenzene with at least one substituent is lower than that of the perovskite mixed solution, defects in the intermediate film formed from the perovskite precursor solution can be repaired during the subsequent process of forming the perovskite active layer. This improves the film quality when forming the perovskite active layer from the perovskite precursor solution, significantly increasing the short-circuit current density and thus enhancing the perovskite solar energy conversion efficiency. Attached Figure Description

[0019] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0020] Figure 1 A flowchart of a method for preparing a perovskite precursor solution according to the present invention is shown;

[0021] Figure 2 A cross-sectional structural schematic diagram of an embodiment of a perovskite solar cell according to the present invention is shown;

[0022] Figure 3 A comparison diagram of the results of the embodiment of the present invention and Comparison 1 is shown.

[0023] The above figures include the following reference numerals:

[0024] 10. Transparent conductive layer; 20. Hole transport layer; 30. Perovskite active layer; 40. Electron transport layer; 50. Cathode buffer layer; 60. Electrode layer. Detailed Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0028] As mentioned in the background section, current main strategies for improving device performance include composition engineering, interface engineering, and additive engineering. These strategies can enhance the light absorption of the photoactive layer, solve energy level matching problems between different interfaces, or passivate various defects in perovskite films caused by rapid crystal growth during solution processing. However, since the efficiency of perovskite solar cells depends on the product of short-circuit current density, open-circuit voltage, and fill factor, and the short-circuit current density is mainly determined by the light absorption range and intensity of the perovskite material, which in turn is determined by the band gap, it is difficult to significantly improve the short-circuit current density by optimizing the quality of the perovskite film. To solve the above technical problems, the inventors of this application propose a perovskite precursor solution, a perovskite active layer, and a method for preparing the same.

[0029] According to one embodiment of the present invention, a perovskite precursor solution is provided, the perovskite precursor solution comprising a perovskite mixed solution and chlorobenzene having at least one substituent, wherein the boiling point of the chlorobenzene having at least one substituent is lower than the boiling point of the perovskite mixed solution.

[0030] The perovskite precursor solution described above is formed by doping a chlorobenzene having at least one substituent into a perovskite mixed solution. Since the boiling point of the chlorobenzene having at least one substituent is lower than that of the perovskite mixed solution, in subsequent processes, when forming the perovskite active layer using the perovskite precursor solution, defects in the intermediate film formed based on the perovskite precursor solution can be repaired. This improves the film quality when forming the perovskite active layer based on the perovskite precursor solution, thereby significantly increasing the short-circuit current density and improving the perovskite solar energy conversion efficiency.

[0031] In some alternative embodiments, the substituents include any one of halogens, C1-C20 alkyl groups, and C1-C20 alkoxy groups. Preferably, the substituents are selected from any one of fluorine, C1-C4 alkyl groups, and C1-C4 alkoxy groups. Further, the chlorobenzene described above includes any one of pentafluorochlorobenzene, p-methylchlorobenzene, and p-methoxychlorobenzene.

[0032] In the above embodiments, when the substituent is fluorine, chlorobenzene having the substituent includes pentafluorochlorobenzene, thereby forming the perovskite precursor solution by doping pentafluorochlorobenzene into the perovskite mixed solution; when the substituent is alkyl, chlorobenzene having the substituent includes p-methylchlorobenzene, thereby forming the perovskite precursor solution by doping p-methylchlorobenzene into the perovskite mixed solution; when the substituent is alkoxy, chlorobenzene having the substituent includes p-methoxychlorobenzene, thereby forming the perovskite precursor solution by doping p-methoxychlorobenzene into the perovskite mixed solution. Since the boiling points of the pentafluorochlorobenzene, p-methylchlorobenzene, and p-methoxychlorobenzene are all lower than the boiling point of the perovskite mixed solution, the film quality when forming the perovskite active layer can be adjusted.

[0033] In some alternative embodiments, the doping percentage of chlorobenzene having at least one substituent in the perovskite mixed solution is 0.5% to 10%.

[0034] In order to form a perovskite precursor solution with good film quality, it is necessary to control the doping amount in the perovskite mixed solution. Therefore, in the above embodiment, a chlorobenzene solution and a perovskite mixed solution can be obtained first, and then the perovskite precursor solution can be obtained according to the ratio of the chlorobenzene solution and the perovskite mixed solution in forming the perovskite precursor solution. Specifically, after doping the chlorobenzene solution into the perovskite mixed solution, the ratio of chlorobenzene to perovskite mixed solution is 1:200 to 1:10.

[0035] In some alternative embodiments, the perovskite mixture includes lead dihalide, ammonium methyl iodide, dimethylamide, and dimethyl sulfoxide.

[0036] In order to form a perovskite mixed solution, in the above embodiments, lead dihalide, methyl ammonium iodide, dimethylamide and dimethyl sulfoxide are mixed to obtain a perovskite mixed solution. For example, the lead dihalide includes lead iodide (PbI2). First, the dimethylamide (DMF) and dimethyl sulfoxide (DMSO) form a first mixed solution, and then lead iodide (PbI2) and methyl ammonium iodide (CH3NH3I) are dissolved in the first mixed solution to form the perovskite mixed solution.

[0037] According to a second embodiment of this application, a method for preparing a perovskite precursor solution is also provided, such as... Figure 1 As shown, it includes the following steps:

[0038] S102: Mix the perovskite precursor material and the organic solvent to obtain a perovskite mixed solution;

[0039] S104: Chlorobenzene with at least one substituent is doped into a perovskite mixed solution to form a perovskite precursor solution.

[0040] The perovskite precursor materials include lead dihalide and ammonium methyl iodide, and the organic solvents include dimethylamide and dimethyl sulfoxide.

[0041] Using the above preparation method, a perovskite mixed solution is first prepared, and then chlorobenzene with at least one substituent is doped into the perovskite mixed solution to form a perovskite precursor solution. Since the boiling point of chlorobenzene with at least one substituent is lower than that of the perovskite mixed solution, the defects of the intermediate film formed based on the perovskite precursor solution can be repaired during the subsequent process of forming the perovskite active layer using the perovskite precursor solution. This improves the film quality when forming the perovskite active layer based on the perovskite precursor solution, thereby significantly increasing the short-circuit current density and improving the perovskite solar energy conversion efficiency.

[0042] In some alternative embodiments, the steps further include: after the step of forming the perovskite mixed solution, stirring the perovskite mixed solution to make the perovskite mixed solution uniformly mixed; and after the step of forming the perovskite precursor solution, filtering the perovskite precursor solution with a polytetrafluoroethylene filter head.

[0043] In the above embodiments, in order to form a uniformly mixed perovskite solution, after forming the perovskite solution, the perovskite solution is stirred overnight, and chlorobenzene having at least one substituent is doped into the perovskite solution. After forming the perovskite precursor solution, in order to make the surface of the perovskite active layer formed from the perovskite precursor solution smoother, a polytetrafluoroethylene (PTFE) filter with a small pore size is used to filter the perovskite precursor solution. For example, the PTFE filter has a pore size of 0.45 μm, so that after filtering the perovskite precursor solution with the filter, some impurities with a pore size greater than 0.45 μm in the perovskite precursor solution can be removed.

[0044] In some alternative embodiments, the amount of chlorobenzene having at least one substituent in the perovskite mixed solution is 10 μL / mL to 100 μL / mL.

[0045] In the above embodiments, by doping the perovskite mixed solution with chlorobenzene having at least one substituent at a concentration of 10 μL / mL to 100 μL / mL, the perovskite precursor solution formed can adjust the film quality of the perovskite precursor film during the preparation of the perovskite active layer, thereby forming a perovskite active layer with a better morphology.

[0046] According to a third embodiment of this application, a method for preparing a perovskite active layer is also provided, comprising the following steps: spin-coating a perovskite precursor solution onto a substrate, wherein the perovskite precursor solution is the perovskite precursor solution in the above embodiments, or the perovskite precursor solution is prepared by a method for preparing a perovskite precursor solution provided in the above embodiments; extracting the perovskite precursor solution using an anti-solvent method during the spin-coating process; and heat-treating the extracted perovskite precursor solution to form a perovskite active layer.

[0047] Specifically, in addition to spin coating, the methods for coating the perovskite precursor solution onto the substrate also include slot extrusion and hang coating. When spin coating the perovskite precursor solution onto the substrate, the rotation speed can be 2000–7000 rpm. Furthermore, in the step of extracting the perovskite precursor solution using an antisolvent method, a chlorobenzene solution can be added dropwise to the perovskite precursor solution spin-coated onto the substrate, thereby effectively controlling the nucleation and crystal growth process of the perovskite active layer and regulating its morphology. The timing of the chlorobenzene solution addition is crucial, ensuring that the solution rapidly reaches supersaturation, thus controlling the nucleation mode and density.

[0048] Using the above preparation method, a pre-prepared perovskite precursor solution is spin-coated onto a substrate. During the spin-coating process, the perovskite precursor solution is extracted using an anti-solvent method, thereby achieving a supersaturated state to form a textured and smooth perovskite precursor film. Subsequently, the perovskite precursor film is heat-treated to further repair defects in the film, forming a high-quality perovskite active layer. This significantly increases the short-circuit current density, thereby improving the perovskite solar energy conversion efficiency.

[0049] In some alternative embodiments, during the extraction of the perovskite precursor solution, a chlorobenzene solution is added dropwise to the perovskite precursor solution on the substrate for extraction before a transparent intermediate film is formed in the perovskite precursor solution on the substrate.

[0050] In the above embodiments, the chlorobenzene solution can be added before the formation of the intermediate film is completed. This intermediate film can be a perovskite precursor film, thus obtaining a perovskite precursor film with a textured or smooth surface. Alternatively, the addition of the chlorobenzene solution can be synchronized with the entire perovskite precursor film formation time. If the addition continues until the end of the entire film formation stage, a dense and relatively thick perovskite precursor film will be obtained. For example, the chlorobenzene solution can be added at 6-8 seconds after the start of film formation or at 15-25 seconds after spin-coating the perovskite precursor solution onto the substrate, with a addition duration of 2-12 seconds. The dropping rate of the chlorobenzene solution can be 0.05-0.5 mL / s, thereby allowing control over the nucleation mode of the perovskite precursor solution, effectively forming continuous grain boundaries with the perovskite precursor solution, and further adjusting the surface texture or ultra-smooth morphology of the film.

[0051] In some alternative embodiments, the heat treatment includes an annealing process at a temperature of 90–150°C for a time of 0–120 min.

[0052] Specifically, the heat treatment methods mentioned above can include hot plate heating, oven heating, sintering furnace heating, microwave heating, laser irradiation treatment, etc.

[0053] In the above embodiments, by annealing the perovskite precursor film, the grains can be further refined, the structural defects of the film can be repaired, the film morphology can be improved, and a perovskite active layer of better quality can be formed.

[0054] According to some optional embodiments, in the step of spin-coating the perovskite precursor solution, the spin-coating rate is determined based on the thickness of the perovskite active layer.

[0055] In the above embodiments, since the thickness of the perovskite active layer is related to the spin-coating rate of the perovskite precursor solution, in order to form a perovskite active layer of suitable thickness, the spin-coating rate needs to be determined before spin-coating. For example, the thickness of the perovskite active layer can be 500–100 nm, and the spin-coating rate can be 3000–4000 rpm / 30 s.

[0056] According to a fourth embodiment of this application, a perovskite active layer is also provided, which is prepared by a method for preparing a perovskite active layer provided in the third aspect of this application.

[0057] The perovskite active layer described above is prepared by using a perovskite precursor solution doped with at least one substituent in a chlorobenzene-perovskite mixed solution. As a result, the perovskite active layer has a high film quality, which can significantly improve the short-circuit current density and thus enhance the perovskite solar energy conversion efficiency.

[0058] According to a fifth embodiment of this application, a perovskite solar cell is also provided, such as... Figure 2 As shown, the perovskite solar cell includes: a transparent conductive layer 10 having a first surface; a hole transport layer 20 disposed in contact with the first surface; a perovskite active layer 30 as provided in one embodiment of this application, disposed on the side of the hole transport layer 20 away from the transparent conductive layer 10; an electron transport layer 40 disposed on the side of the perovskite active layer 30 away from the hole transport layer 20; and an electrode layer 60 disposed on the side of the electron transport layer 40 away from the perovskite active layer 30.

[0059] The transparent conductive layer 10 can be made of rigid or flexible materials. Rigid materials include conductive glass FTO and conductive glass ITO, while flexible materials include metal-based (sputtered or metal grid type) or oxide transparent conductive films such as ITO, which are based on polymer films such as polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyimide (PI), polycarbonate (PC), polyaniline, and polypyrrole. For example, the thickness of the transparent conductive layer 10 can be 0.1 to 10 mm.

[0060] Before forming the hole transport layer 20 on the transparent conductive layer 10, the layer is ultrasonically cleaned using RBS glass cleaner, deionized water, acetone, and isoacetone, respectively, then dried and set aside for later use. Following this, it undergoes ultraviolet ozone treatment before the hole transport layer 20 is formed on the first surface of the transparent conductive layer 10, ensuring contact between the hole transport layer 20 and the first surface. In forming the hole transport layer 20, a precursor solution is first prepared. For example, a nickel oxide precursor solution can be used to form the hole transport layer 20. For example, the thickness of the hole transport layer 20 can be 10–200 nm.

[0061] In some optional embodiments, the hole transport layer 20 may be an inorganic hole transport material and / or an organic hole transport material, such as nickel trioxide (NiO), cuprous iodide (CuI), cuprous thiocyanate (CuSCN), molybdenum trioxide (MoO3), vanadium pentoxide (V2O5), tungsten trioxide (WO3), molybdenum disulfide (MoS2), tungsten disulfide (WS2), cobalt selenide (CoSe), copper selenide (CuSe), carbonyl sulfide (CoS), vanadium carbide (VC), chromium carbide (Cr3C2), titanium carbide (TiC), vanadium nitride (VN), and polythiophene derivatives. The inorganic hole transport material comprises one or more of the following: PEDOT, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), poly(3,4-ethylenedioxythiophene):p-toluenesulfonate (PEDOT:TSO), 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, poly(3-hexylthiophene-2,5-diyl), poly[bis(4-phenyl)(2,4,62,4,62,4,62,4,6-trimethylphenyl)amine], polypyrrole (PPy), polyaniline (PANI), etc., or mixtures thereof, or dopants thereof, or mixtures of dopants. The particle size of the inorganic hole transport material can be 5–500 nm, preferably nanomaterials.

[0062] Specifically, such as Figure 2 As shown, the nickel oxide precursor solution can be prepared using a sol-gel method. Nickel acetate (Ni(Ac)₂·4H₂O), ethanol, and ethylamine can be used to form the nickel oxide precursor solution. The formed nickel oxide precursor solution is then stirred overnight, and subsequently spin-coated onto the first surface of the transparent conductive layer 10. Annealing is then performed to form the hole transport layer 20. The structure having the transparent conductive layer 10 and the hole transport layer 20 is then transferred to a nitrogen glove box to form the perovskite active layer 30 as described in an embodiment of this application. Exemplarily, the thickness of the perovskite active layer 30 can be 100–600 nm.

[0063] Furthermore, such as Figure 2 As shown, after forming the perovskite active layer 30, an electron transport layer 40 is formed on the side of the perovskite active layer 30 away from the hole transport layer 20. This electron transport layer 40 can be formed by spin-coating a mixed solution of chlorobenzene and fullerene derivatives onto the surface of the perovskite active layer 30 away from the hole transport layer 20. Exemplarily, the thickness of this electron transport layer can be 20–600 nm. Further, the prepared sample is transferred to a vapor deposition machine, and a silver electrode is deposited on the electron transport layer 40 by thermal evaporation to form an electrode layer 60, thereby forming the perovskite solar cell, and the effective area of ​​the perovskite solar cell includes 0.1 cm². 2 .

[0064] In the structure of the perovskite solar cell described above, the perovskite active layer 30 is formed by preparing the perovskite precursor solution. In this perovskite solar cell, the perovskite active layer 30 is disposed between the hole transport layer 20 and the electron transport layer 40. Since the perovskite active layer 30 has a high film quality, it can significantly improve the short-circuit current density, thereby improving the perovskite solar energy conversion efficiency.

[0065] In some alternative implementations, such as Figure 2 As shown, the perovskite solar cell further includes: a cathode buffer layer 50, which is disposed on the side of the electron transport layer 40 away from the perovskite active layer 30, and an electrode layer 60 is disposed on the side of the cathode buffer layer 50 away from the electron transport layer 40.

[0066] The cathode buffer layer 50 can be formed by spin-coating a mixed solution of isopropanol and block copolymer onto the side of the electron transport layer 40 away from the perovskite active layer 30.

[0067] In the above embodiments, by adding a cathode buffer layer 50 between the electron transport layer 40 and the electrode layer 60, the contact barrier between the electron transport layer 40 and the electrode layer 60 is effectively reduced, the electron mobility is increased, the ohmic contact is reduced, and thus the efficiency of electrons being transported from the perovskite active layer 30 to the electrode layer 60 is increased.

[0068] The following will further illustrate the above-mentioned perovskite active layer of the present invention and its preparation method with reference to embodiments and comparative examples.

[0069] Example 1

[0070] The method for fabricating perovskite solar cells provided in this embodiment includes the following steps:

[0071] Conductive glass is provided, the transparent conductive layer is fluorine-doped tin oxide (FTO) and the thickness of the transparent conductive layer is 200nm. The conductive glass is pretreated by sequentially cleaning the conductive glass with glass cleaning agent, deionized water, acetone and isoacetone for 15min, and then placed in a vacuum drying oven at 60℃ to dry for later use.

[0072] Dissolve 0.1 mol of nickel acetate (Ni(Ac)₂·4H₂O) in 1 mL of ethanol, and add Ni(Ac) in a molar ratio of 1:1 (Ni(Ac)₂·4H₂O) to form a ethanol solution. 2+ The nickel oxide precursor solution was prepared by stirring at 70°C for 4 hours to form a nickel oxide precursor solution. The nickel oxide precursor solution was then spin-coated onto a transparent conductive layer at 4000 rpm for 30 seconds. The layer was then annealed in air at 280°C for 1 hour to form a hole transport layer.

[0073] 1.1 M lead iodide (PbI2) and 1 M methyl ammonium iodide (CH3NH3I) were dissolved in a mixed solvent of dimethyl amide (DMF) and dimethyl sulfoxide (DMSO) in a volume ratio of 7:3 to form a perovskite mixed solution. The solution was stirred at 60 °C for 10 h, and chlorobenzene (CB) was added to the perovskite mixed solution at a rate of 60 μL / mL to prepare a doped perovskite precursor solution. The perovskite precursor solution was then filtered using a polytetrafluoroethylene filter with a pore size of 0.45 μm. The perovskite precursor solution was then spin-coated onto the surface of the hole transport layer away from the transparent conductive layer at a speed of 4000 rpm / 30 s to form a perovskite precursor film. When the perovskite precursor film became transparent, 100 μL of chlorobenzene solution was added dropwise for extraction. The perovskite precursor film was then placed on a heating plate at 100 °C and annealed for 10 min to form the perovskite active layer.

[0074] A mixed solution of chlorobenzene and fullerene derivative (PCBM) (20 mg / mL) was spin-coated to the surface of the perovskite active layer away from the hole transport layer at a speed of 2000 rpm / 30 s to form an electron transport layer with a thickness of 50 nm.

[0075] A mixed solution of isopropanol and block copolymer (BCP) (0.5 mg / mL) was spin-coated at a speed of 4000 rpm / 30 s to the side of the electron transport layer away from the perovskite active layer to form a cathode buffer layer with a thickness of 3 nm.

[0076] The prepared sample was transferred to a vapor deposition machine and deposited at 10°C. -5 In Torr's vacuum chamber, an 80nm silver electrode is deposited on the electron transport layer by thermal evaporation to form an electrode layer.

[0077] Example 2

[0078] The difference between Example 2 and Example 1 is that the amount of chlorobenzene doped is different. In Example 2, chlorobenzene (CB) is added to the above perovskite mixed solution at a rate of 100 μL / mL.

[0079] Example 3

[0080] The difference between Example 2 and Example 1 lies in the extraction conditions. In Example 3, 100 μL of chlorobenzene solution was added dropwise for extraction before the perovskite precursor film became transparent.

[0081] Comparative Example 1

[0082] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not contain chlorobenzene.

[0083] The conditions for forming the perovskite active layer in Examples 1, 2, 3 and Comparative Example 1 are shown in Table 1:

[0084] Table 1

[0085]

[0086] The performance of the perovskite solar cells prepared above was tested, and the test results are shown in Table 2 and... Figure 3 As shown:

[0087] Table 2

[0088]

[0089] Among them, V oc Represented as open-circuit voltage, J sc It is represented by short-circuit current, FF represents the fill factor, and PCE represents the conversion efficiency. Figure 3 The dashed line corresponds to Comparative Example 1, and the solid line corresponds to Example 1.

[0090] As can be seen from Tables 1 and 2, the main factors affecting the short-circuit current density and solar energy conversion efficiency of perovskite solar cells are the doping amount of chlorobenzene in the perovskite mixed solution and the extraction conditions when spin-coating the perovskite precursor solution and extracting to form a perovskite precursor film. Therefore, doping the perovskite mixed solution with chlorobenzene to form the perovskite active layer of the perovskite solar cell and controlling the extraction conditions to add the chlorobenzene solution dropwise before forming the transparent perovskite precursor film can significantly improve the short-circuit current density of the perovskite solar cell, thereby improving the perovskite solar energy conversion efficiency.

[0091] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0092] The perovskite precursor solution is formed by doping a perovskite mixed solution with chlorobenzene having at least one substituent, which has a low boiling point. Since the boiling point of chlorobenzene having at least one substituent is lower than that of the perovskite mixed solution, defects in the perovskite precursor film formed from the perovskite precursor solution can be repaired during the subsequent process of forming the perovskite active layer using the perovskite precursor solution. This improves the film quality when forming the perovskite active layer using the perovskite precursor solution, thereby significantly increasing the short-circuit current density and improving the perovskite solar energy conversion efficiency.

[0093] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A perovskite precursor solution, characterized in that, The method includes a perovskite mixed solution and chlorobenzene having at least one substituent, wherein the boiling point of the chlorobenzene having at least one substituent is lower than the boiling point of the perovskite mixed solution, such that defects in the intermediate film formed according to the perovskite precursor solution are repaired during the formation of the perovskite active layer using the perovskite precursor solution.

2. The perovskite precursor solution according to claim 1, characterized in that, The substituent includes any one of halogen, C1-C20 alkyl and C1-C20 alkoxy groups, preferably selected from any one of fluorine, C1-C4 alkyl and C1-C4 alkoxy groups.

3. The perovskite precursor solution according to claim 1, characterized in that, The doping ratio of chlorobenzene having at least one substituent in the perovskite mixed solution is 0.5-10%.

4. The perovskite precursor solution according to claim 1 or 2, characterized in that, The chlorobenzene having at least one substituent includes any one of pentafluorochlorobenzene, p-methylchlorobenzene, and p-methoxychlorobenzene.

5. The perovskite precursor solution according to any one of claims 1 to 4, characterized in that, The perovskite mixed solution includes lead dihalide, ammonium methyl iodide, dimethylamide, and dimethyl sulfoxide.

6. A method for preparing a perovskite precursor solution according to any one of claims 1 to 5, characterized in that, Includes the following steps: The perovskite precursor material and the organic solvent are mixed to obtain a perovskite mixed solution; Chlorobenzene having at least one substituent is doped into the perovskite mixed solution to form the perovskite precursor solution.

7. The preparation method according to claim 6, characterized in that, The content of chlorobenzene having at least one substituent in the perovskite mixed solution is 10 μL / mL to 100 μL / mL.

8. A method for preparing a perovskite active layer, characterized in that, Includes the following steps: A perovskite precursor solution is spin-coated onto a substrate, wherein the perovskite precursor solution is the perovskite precursor solution according to any one of claims 1 to 5, or the perovskite precursor solution is prepared by the preparation method according to claim 6 or 7. The perovskite precursor solution was extracted using an antisolvent method during spin coating. The extracted perovskite precursor solution is heat-treated to form the perovskite active layer.

9. The preparation method according to claim 8, characterized in that, In the step of extracting the perovskite precursor solution, before the perovskite precursor solution on the substrate forms a transparent intermediate film, a chlorobenzene solution is added dropwise to the perovskite precursor solution on the substrate for extraction.

10. The preparation method according to claim 8, characterized in that, In the step of spin-coating the perovskite precursor solution, the spin-coating rate is determined based on the thickness of the perovskite active layer.

11. A perovskite active layer, characterized in that, The perovskite active layer is prepared by the preparation method according to any one of claims 8 to 10.

12. A perovskite solar cell, characterized in that, include: A transparent conductive layer having a first surface; A hole transport layer is disposed in contact with the first surface; The perovskite active layer as described in claim 11, wherein the perovskite active layer is disposed on the side of the hole transport layer away from the transparent conductive layer; An electron transport layer is disposed on the side of the perovskite active layer away from the hole transport layer; An electrode layer is disposed on the side of the electron transport layer away from the perovskite active layer.

13. The perovskite solar cell according to claim 12, characterized in that, Also includes: A cathode buffer layer is disposed on the side of the electron transport layer away from the perovskite active layer, and the electrode layer is disposed on the side of the cathode buffer layer away from the electron transport layer.

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