Nickel oxide thin film, preparation method thereof and perovskite battery

Abstract

The invention relates to a nickel oxide thin film, a preparation method thereof and a perovskite battery. The preparation method comprises the following steps: mixing nickel salt and a ligand to obtain a nickel complex; dispersing the nickel complex in a solvent to obtain a sol-gel complex solution; performing first spin coating on the surface of a substrate with the sol-gel complex solution, and performing first thermal annealing to prepare the nickel oxide thin film; the ligand has a chemical formula as shown in a formula 1. According to the preparation method, hydrogen of a carbon chain of ethylenediamine is replaced by alkyl, the molecular configuration of ethylenediamine is changed, then the steric hindrance of ethylenediamine is changed, and the ethylenediamine is complexed with nickel salt as a ligand, so that the oxidation state or the coordination environment of nickel ions can be effectively regulated and controlled, and the crystallinity and the conductivity of the prepared nickel oxide thin film are improved. Meanwhile, based on a sol-gel complex solution spin-coating preparation mode, the prepared nickel oxide film has good uniformity, and agglomeration of nickel oxide particles is effectively avoided.

Description

Technical Field

[0001] This invention relates to the field of perovskite battery technology, specifically to a nickel oxide hole transport layer, and more particularly to a nickel oxide thin film, its preparation method, and a perovskite battery. Background Technology

[0002] Perovskite solar cells have attracted increasing attention due to their simple structure, low-temperature processing capability, and low hysteresis. The hole transport layer plays a crucial role in planar perovskite solar cells. Nickel oxide is a typical inorganic p-type semiconductor with a wide band gap, good transmittance in the visible spectrum, and excellent chemical stability and perovskite energy level matching, which facilitates better hole collection and electron blocking.

[0003] CN118102743A discloses a nickel oxide hole transport layer inverted perovskite solar cell and its preparation method. This invention involves spinning nickel oxide onto a transparent conductive oxide, followed by hydrogen reduction of the high-valence nickel oxide. This allows NiO nanoparticles to more easily form a dense, stable, and flat thin film, facilitating the absorption of more light by the perovskite light-absorbing layer and enabling charge carriers to pass through the interface. This improves photoelectric conversion efficiency from both optical and electrical perspectives, providing a more stable inverted perovskite solar cell.

[0004] CN117812979A discloses a hole transport layer of rare earth-doped nickel oxide, its preparation method, and its application. The method includes: dissolving nickel salt and rare earth salt in water to prepare a precursor solution; adding sodium hydroxide solution dropwise to the precursor solution until the solution pH is 9.5–10.5; washing away the precipitated material and drying it to obtain rare earth-doped nickel hydroxide; calcining the rare earth-doped nickel hydroxide and cooling it to room temperature to obtain rare earth-doped nickel oxide; dispersing the obtained rare earth-doped nickel oxide in a solvent, sonicating it, filtering it, spin-coating the filtered dispersion onto ITO, and annealing it. The rare earth-doped nickel oxide prepared by this invention has a well-defined structure and can be dispersed in water for a long time. By controlling the different contents of the doped rare earth elements, the hole transport layer's wetted surface area (WF) and conductivity can be adjusted, thereby promoting effective hole collection.

[0005] CN118540961A discloses a nickel oxide hole transport layer, a perovskite solar cell, and a fabrication method thereof. The nickel oxide hole transport layer comprises a nickel oxide layer doped with nickel oxide nanoparticles modified with hydrogen peroxide; wherein the hydrogen peroxide-modified nickel oxide nanoparticles form a p-type dopant with the nickel oxide substrate. This invention introduces hydrogen peroxide into the nickel oxide nanoparticles, which react with the nickel oxide itself to generate more p-type doped Ni. 3+It exists in the transport layer in the form of NiOOH, which accelerates the extraction and transfer of holes and can effectively improve the hysteresis effect in perovskite solar cells. After the addition of hydrogen peroxide, the size of nickel oxide nanoparticles decreases and their dispersion in solution is better, thus obtaining a more uniform and dense film, effectively improving the film quality of nickel oxide, and thus obtaining a more efficient and stable perovskite solar cell.

[0006] In the prior art, high-efficiency devices are usually based on low-temperature prepared nano-nickel oxide particles, but they are prone to agglomeration and uneven coating on FTO substrates, making them unsuitable for large-area applications.

[0007] Therefore, it is of great significance to provide a nickel oxide thin film with better coating uniformity, high crystallinity, high electrical conductivity, and suitable for large-area preparation, as well as its preparation method. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a nickel oxide thin film, its preparation method, and a perovskite battery. The present invention modifies the molecular configuration and steric hindrance of the ethylenediamine carbon chain by substituting hydrogen atoms with alkyl groups, resulting in a material with the chemical formula shown in Formula 1. Using this material as a ligand to complex with nickel salts, the oxidation state or coordination environment of nickel ions can be effectively controlled, thereby improving the crystallinity and conductivity of the prepared nickel oxide thin film. Furthermore, based on the sol-gel complex solution spin-coating method, the prepared nickel oxide thin film exhibits good uniformity, effectively preventing the agglomeration of nickel oxide particles.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a method for preparing a nickel oxide thin film, the method comprising:

[0011] A nickel salt and a ligand are mixed to obtain a nickel complex; the nickel complex is dispersed in a solvent to obtain a sol-gel complex solution; the sol-gel complex solution is first spin-coated onto a substrate surface and then subjected to a first thermal annealing to prepare the nickel oxide film; the ligand has the chemical formula shown in Formula 1:

[0012] Formula 1.

[0013] R1 and R2 are each independently H, a chain alkyl group or a cycloalkyl group, and R1 and R2 are not both H.

[0014] This invention modifies the molecular configuration and steric hindrance of ethylenediamine carbon chains by substituting hydrogen atoms with alkyl groups, resulting in a material with the chemical formula shown in Formula 1. Using this material as a ligand to complex with nickel salts, the oxidation state or coordination environment of nickel ions can be effectively controlled, thereby improving the crystallinity and conductivity of the prepared nickel oxide film. Based on a sol-gel complex solution spin-coating method, the nickel oxide film prepared by this invention exhibits good uniformity and effectively avoids the agglomeration of nickel oxide particles.

[0015] Preferably, in Formula 1, the chemical formula of the chain alkyl group is -C n H 2n+1 , 1≤n≤7.

[0016] Preferably, in Formula 1, the cycloalkyl group has the chemical formula -C m H 2m-1 , 4≤m≤6.

[0017] Preferably, in Formula 1, R1 and R2 are not both cycloalkyl groups.

[0018] Preferably, the molar ratio of the nickel salt to the ligand is (1~1.5):1.

[0019] Preferably, the nickel salt includes any one or a combination of at least two of nickel nitrate, nickel sulfate, nickel acetate, or nickel chloride.

[0020] Preferably, the solvent includes any one or a combination of at least two of ethylene glycol, propylene glycol, or isopropanol.

[0021] Preferably, the concentration of the nickel complex in the sol-gel complex solution is 10 mg / mL to 30 mg / mL.

[0022] Preferably, the rotation speed of the first spin coating is 2500 rpm to 4500 rpm.

[0023] Preferably, the spin coating time is 20s to 60s.

[0024] Preferably, the temperature of the first heat annealing is 200℃~400℃.

[0025] Preferably, the first heat annealing time is 0.5h to 2h.

[0026] Preferably, the preparation method further includes, after the first thermal annealing, a second thermal annealing is performed by spin-coating a [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid solution onto the surface of the nickel oxide film.

[0027] Preferably, the concentration of the [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid solution is 0.3 mg / mL to 1 mg / mL.

[0028] Preferably, the solvent of the [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid solution includes isopropanol.

[0029] Preferably, the rotation speed of the second spin coating is 2500 rpm to 3500 rpm.

[0030] Preferably, the second spin coating time is 10s to 30s.

[0031] Preferably, the temperature of the second heat annealing is 80°C to 120°C.

[0032] Preferably, the second heat annealing time is 8 min to 15 min.

[0033] In a second aspect, the present invention provides a nickel oxide thin film, which is prepared by the preparation method described in the first aspect.

[0034] Thirdly, the present invention provides a perovskite solar cell, the perovskite solar cell comprising a substrate, a hole transport layer, a perovskite active layer, a passivation layer, a functional layer and a metal electrode stacked sequentially; the hole transport layer is made of a nickel oxide thin film as described in the second aspect.

[0035] Preferably, the material of the perovskite active layer includes Cs. x FA 1-x PbI3, 0 < x < 0.1.

[0036] Preferably, the passivation layer is made of meta-fluorine-substituted phenethylamine bromide and benzimidazole.

[0037] Preferably, the functional layer includes C 60 Functional layers and / or tin oxide functional layers.

[0038] Preferably, the metal electrode includes a gold electrode or a silver electrode.

[0039] Preferably, the substrate is made of any one of fluorine-doped tin oxide, indium-doped tin oxide, or aluminum-doped zinc oxide.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The present invention uses alkyl groups to replace the hydrogen in the carbon chain of ethylenediamine to change its molecular configuration and thus change its steric hindrance, thereby obtaining a material with the chemical formula shown in Formula 1. Using it as a ligand to complex with nickel salt, the oxidation state or coordination environment of nickel ions can be effectively controlled, thereby improving the crystallinity and conductivity of the prepared nickel oxide film.

[0042] (2) The present invention is based on the preparation method of spin coating of sol-gel complex solution. The nickel oxide film prepared has good uniformity and effectively avoids the agglomeration of nickel oxide particles. Detailed Implementation

[0043] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0044] The "range" disclosed in this invention can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. This type of range definition can include or exclude endpoints; any endpoint can be independently included or excluded, and they can be arbitrarily combined, meaning any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for specific parameters, it is understood that ranges of 60~110 and 80~120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0045] In this invention, "a combination of at least two" refers to a quantity greater than or equal to two, unless otherwise specified. For example, "any combination of one or at least two" means one or more or more items. It can be understood that when referring to "a combination of at least two," it refers to any suitable combination of multiple items, that is, a combination of "at least two" items carried out in a manner that does not conflict with and enables the implementation of this invention.

[0046] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0047] The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0048] Those skilled in the art will understand that the order in which the steps are written in the methods of the various embodiments does not imply a strict execution order. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), meaning that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0049] In this invention, open-ended technical features or solutions described using terms such as "comprising" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or exclude additional members. This can be considered as providing both technical features or solutions where "A is composed of a1, a2, and a3" or "A is selected from a1, a2, and a3," and technical features or solutions where "A includes not only a1, a2, and a3, but also other members."

[0050] In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" represents a group consisting of A, B, and "a combination of A and B". "Containing A and / or B" can mean "containing A, containing B, and containing A and B", or "containing A, containing B, or containing A and B", and can be appropriately understood according to the context.

[0051] In this invention, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on the quantity.

[0052] In this invention, "optional" means that something is optional, that is, it refers to either "with" or "without". If there are multiple "optional" options in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, then each "optional" option is independent.

[0053] In this invention, unless otherwise specified, it is assumed that the experiments are conducted at room temperature or a temperature conventionally set in the art. "Room temperature" generally refers to 4°C to 35°C, and may refer to 20°C ± 5°C. In some embodiments of this invention, room temperature refers to 20°C to 30°C.

[0054] In one specific embodiment, the present invention provides a method for preparing a nickel oxide thin film, the method comprising:

[0055] A nickel salt and a ligand are mixed to obtain a nickel complex; the nickel complex is dispersed in a solvent to obtain a sol-gel complex solution; the sol-gel complex solution is first spin-coated onto a substrate surface and then subjected to a first thermal annealing to prepare the nickel oxide film; the ligand has the chemical formula shown in Formula 1:

[0056] Formula 1.

[0057] R1 and R2 are each independently H, a chain alkyl group or a cycloalkyl group, and R1 and R2 are not both H.

[0058] This invention modifies the molecular configuration and steric hindrance of ethylenediamine carbon chains by substituting hydrogen atoms with alkyl groups, resulting in a material with the chemical formula shown in Formula 1. Using this material as a ligand to complex with nickel salts, the oxidation state or coordination environment of nickel ions can be effectively controlled, thereby improving the crystallinity and conductivity of the prepared nickel oxide film. Based on a sol-gel complex solution spin-coating method, the nickel oxide film prepared by this invention exhibits good uniformity and effectively avoids the agglomeration of nickel oxide particles.

[0059] In some embodiments, the chemical formula of the chain alkyl group in Formula 1 is -C n H 2n+1 , 1≤n≤7, for example, it can be 1, 2, 3, 4, 5, 6 or 7.

[0060] In some embodiments, the cycloalkyl group in Formula 1 has the chemical formula -C m H 2m-1 , 4≤m≤6, for example, it can be 4, 5 or 6.

[0061] The following are the chemical formulas of some of the ligands:

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069] In some embodiments, R1 and R2 in Formula 1 are not both cycloalkyl.

[0070] In some embodiments, the molar ratio of the nickel salt to the ligand is (1~1.5):1, for example, it can be 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1 or 1.5:1.

[0071] In some embodiments, the nickel salt includes any one or a combination of at least two of nickel nitrate, nickel sulfate, nickel acetate, or nickel chloride. Typical but non-limiting combinations include a combination of nickel nitrate and nickel sulfate, or a combination of nickel acetate and nickel chloride.

[0072] In some embodiments, the solvent includes any one or a combination of at least two of ethylene glycol, propylene glycol, or isopropanol. Typical but non-limiting combinations include a combination of ethylene glycol and propylene glycol, a combination of isopropanol and ethylene glycol, or a combination of propylene glycol and isopropanol.

[0073] In some embodiments, the concentration of the nickel complex in the sol-gel complex solution is 10 mg / mL to 30 mg / mL, for example, it can be 10 mg / mL, 15 mg / mL, 20 mg / mL, 25 mg / mL or 30 mg / mL.

[0074] In some embodiments, the rotation speed of the first spin coating is 2500 rpm to 4500 rpm, for example, it can be 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm or 4500 rpm.

[0075] In some embodiments, the spin coating time is 20s to 60s.

[0076] In some embodiments, the temperature of the first heat annealing is 200°C to 400°C, for example, it can be 200°C, 250°C, 300°C, 350°C or 400°C.

[0077] In some embodiments, the first heat annealing time is 0.5h to 2h, for example, it can be 0.5h, 1h, 1.5h or 2h.

[0078] In some embodiments, the preparation method further includes, after the first thermal annealing, a second thermal annealing is performed by spin-coating a [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid solution onto the surface of the nickel oxide film.

[0079] In some embodiments, the concentration of the [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid solution is 0.3 mg / mL to 1 mg / mL, for example, it can be 0.3 mg / mL, 0.4 mg / mL, 0.5 mg / mL, 0.6 mg / mL, 0.7 mg / mL, 0.8 mg / mL, 0.9 mg / mL or 1 mg / mL.

[0080] In some embodiments, the solvent of the [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid solution includes isopropanol.

[0081] In some embodiments, the rotation speed of the second spin coating is 2500 rpm to 3500 rpm, for example, it can be 2500 rpm, 2750 rpm, 3000 rpm, 3250 rpm or 3500 rpm.

[0082] In some embodiments, the second spin coating time is 10s to 30s.

[0083] In some embodiments, the temperature of the second heat annealing is 80°C to 120°C, for example, it can be 80°C, 90°C, 100°C, 110°C or 120°C.

[0084] In some embodiments, the second heat annealing time is 8 min to 15 min, for example, it can be 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min or 15 min.

[0085] In another specific embodiment, the present invention provides a nickel oxide thin film, which is prepared by the preparation method described in one of the foregoing specific embodiments.

[0086] In yet another embodiment, the present invention provides a perovskite solar cell, the perovskite solar cell comprising a substrate, a hole transport layer, a perovskite active layer, a passivation layer, a functional layer, and a metal electrode stacked sequentially; the hole transport layer is made of a nickel oxide thin film as described in another embodiment above.

[0087] In some embodiments, the material of the perovskite active layer includes Cs. x FA 1-x PbI3, 0 < x < 0.1, for example, can be 0.01, 0.03, 0.05, 0.07 or 0.09.

[0088] In some embodiments, the passivation layer is made of meta-fluorine-substituted phenethylamine bromide (MF-PEABr) and benzimidazole (PDI).

[0089] In some implementations, the functional layer includes C 60 Functional layers and / or tin oxide functional layers.

[0090] In some embodiments, the metal electrode includes a gold electrode or a silver electrode.

[0091] In some embodiments, the substrate material includes any one of fluorine-doped tin oxide (FTO), indium-doped tin oxide (ITO), or aluminum-doped zinc oxide (AZO). Before use, the substrate is further subjected to cleaning to remove surface impurities and oil, followed by ozone treatment for 15 to 30 minutes, for example, 15, 20, 25, or 30 minutes.

[0092] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0093] Example 1

[0094] This embodiment provides a method for preparing a nickel oxide thin film, including:

[0095] (1) Place the cleaned FTO conductive glass substrate in an ultraviolet ozone treatment machine and ozone treat for 20 minutes.

[0096] (2) Nickel nitrate and 1,2-butanediamine with the molecular formula shown in No.2 were mixed at a molar ratio of 1.25:1 to obtain a nickel complex; the nickel complex was dispersed in ethylene glycol to obtain a sol-gel complex solution with a nickel complex concentration of 20 mg / mL.

[0097] (3) The sol-gel complex solution was spin-coated onto the surface of an FTO conductive glass substrate at a speed of 4000 rpm for 40 s. After spin-coating, the substrate was placed on a hot plate at 300°C for a first heat annealing time of 1 h. Next, a solution of 0.6 mg / mL [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid in isopropanol was spin-coated at a speed of 3000 rpm for 15 s. After spin-coating, the substrate was placed on a hot plate at 100°C for a second heat annealing time of 10 min to prepare the nickel oxide film.

[0098] Example 2

[0099] This embodiment provides a method for preparing a nickel oxide thin film, including:

[0100] (1) Place the cleaned FTO conductive glass substrate in an ultraviolet ozone treatment machine and treat it with ozone for 15 minutes.

[0101] (2) Nickel acetate and 1,2-hexanediamine with the molecular formula shown in No. 5 were mixed in a molar ratio of 1:1 to obtain a nickel complex; the nickel complex was dispersed in ethylene glycol to obtain a sol-gel complex solution with a nickel complex concentration of 10 mg / mL.

[0102] (3) The sol-gel complex solution was spin-coated onto the surface of an FTO conductive glass substrate at a speed of 2500 rpm for 60 s. After spin-coating, the substrate was placed on a hot plate at 200°C for a first thermal annealing time of 2 h. Next, a 0.4 mg / mL isopropanol solution of [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid was spin-coated at a speed of 2500 rpm for 30 s. After spin-coating, the substrate was placed on a hot plate at 80°C for a second thermal annealing time of 15 min to prepare the nickel oxide film.

[0103] Example 3

[0104] This embodiment provides a method for preparing a nickel oxide thin film, including:

[0105] (1) Place the cleaned ITO conductive glass substrate in an ultraviolet ozone treatment machine and ozone treat for 30 minutes.

[0106] (2) Nickel nitrate and 3,4-hexanediamine with the molecular formula No. 30 were mixed at a molar ratio of 1.5:1 to obtain a nickel complex; the nickel complex was dispersed in ethylene glycol to obtain a sol-gel complex solution with a nickel complex concentration of 30 mg / mL.

[0107] (3) The sol-gel complex solution was spin-coated onto the surface of an FTO conductive glass substrate at a speed of 4500 rpm for 20 s. After spin-coating, the substrate was placed on a hot plate at 400°C for a first thermal annealing time of 0.5 h. Next, a solution of 0.8 mg / mL [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid in isopropanol was spin-coated at a speed of 3500 rpm for 10 s. After spin-coating, the substrate was placed on a hot plate at 120°C for a second thermal annealing time of 8 min to prepare the nickel oxide film.

[0108] Example 4

[0109] This embodiment provides a method for preparing nickel oxide thin films. Except for step (2), in which an equal amount of 1-aminomethylcyclopentylamine with the molecular formula No. 47 is used to replace 1,2-butanediamine in Example 1, the rest is the same as in Example 1.

[0110] Example 5

[0111] This embodiment provides a method for preparing nickel oxide thin films. Except for step (2), in which an equal amount of 1-cyclopentylethane-1,2-diamine with the molecular formula No. 45 is used to replace the 1,2-butanediamine in Example 1, the rest is the same as in Example 1.

[0112] Example 6

[0113] This embodiment provides a method for preparing nickel oxide thin films. Except for step (2), in which an equal amount of 1-cycloheptylethane-1,2-diamine with the molecular formula No. 49 is used to replace the 1,2-butanediamine in Example 1, the rest is the same as in Example 1.

[0114] Example 7

[0115] This embodiment provides a method for preparing nickel oxide thin films. Except for step (2), in which an equal amount of 3,3-dimethylbutane-1,2-diamine with the molecular formula shown in No. 7 is used to replace the 1,2-butanediamine in Example 1, the rest is the same as in Example 1.

[0116] Example 8

[0117] This embodiment provides a method for preparing nickel oxide thin films. Except for step (2), in which an equal amount of 2,2,5,5-tetramethylhexane-3,4-diamine with the molecular formula shown in No. 54 is used to replace the 1,2-butanediamine in Example 1, the rest is the same as in Example 1.

[0118] Example 9

[0119] This embodiment provides a method for preparing nickel oxide thin films. Except for step (2), which involves mixing nickel nitrate and 1,2-butanediamine (with the molecular formula No. 2) at a molar ratio of 0.8:1 to obtain a nickel complex, the rest of the method is the same as in Example 1.

[0120] Example 10

[0121] This embodiment provides a method for preparing nickel oxide thin films. Except for step (2), which involves mixing nickel nitrate and 1,2-butanediamine (as shown in No. 2) in a molar ratio of 2:1 to obtain a nickel complex, the rest of the method is the same as in Example 1.

[0122] Comparative Example 1

[0123] This comparative example provides a method for preparing a nickel oxide thin film. Except for step (2), in which an equal amount of ethylenediamine with the molecular formula shown in Formula 2 is used to replace the 1,2-butanediamine in Example 1, the rest is the same as in Example 1.

[0124] Equation 2.

[0125] Comparative Example 2

[0126] This comparative example provides a method for preparing a nickel oxide thin film. Except for step (2), in which an equal amount of butanediamine with the molecular formula shown in Formula 3 is used to replace the 1,2-butanediamine in Example 1, the rest is the same as in Example 1.

[0127] Formula 3.

[0128] Performance testing:

[0129] The nickel oxide thin film prepared using all the above embodiments and comparative examples was used as the hole transport layer, with a preparation area of ​​0.06 cm². 2 The specific preparation method of the perovskite solar cell is as follows:

[0130] A mixture of 18.2 mg CsI, 228.4 mg FAI, and 645.42 mg PbI2 was dissolved in a mixed solvent of DMF and DMSO (4:1, v / v). The solution was stirred at 60 °C for 2 hours until fully dissolved, yielding a solution with a concentration of 1.4 mol / L and a composition of CsI. 0.05 FA 0.95 PbI3 perovskite precursor solution. 50 µL of the perovskite precursor solution was spin-coated onto the hole transport layer. The spin-coating speed was 1000 rpm for 10 s, followed by 4000 rpm for 40 s. During the 30th to 35th s of the 4000 rpm spin-coating, 100 µL of the anti-solvent chlorobenzene was added dropwise. The sample was then annealed on a hot plate at 100 °C for 10 min to form the perovskite active layer.

[0131] Next, 3.6 mg MF-PEABr and 5 mg PDI powder were dissolved in isopropanol solution, heated to 60 °C and stirred for 1 h to prepare a 0.6 mg / mL MF-PEABr+PDI passivation layer precursor solution; 100 µL of the passivation layer precursor solution was spin-coated onto the surface of the perovskite active layer at 5000 rpm for 30 s, and then heat-annealed at 100 °C for 5 min to obtain the passivation layer.

[0132] Finally, a 35 nm thick C60 electrode, a 7 nm thick SnO2 electrode, and a 100 nm thick Ag electrode were sequentially deposited on the passivation layer surface to prepare a complete electrode with an area of ​​0.06 cm². 2 Perovskite solar cells.

[0133] Under standard sunlight (AM1.5G) irradiation, the prepared perovskite solar cells were subjected to forward and reverse scanning tests to measure the photoelectric conversion efficiency (PCE), short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF). The forward scan test results are shown in Table 1, and the reverse scan test results are shown in Table 2.

[0134] Table 1

[0135]

[0136] Table 2

[0137]

[0138] In summary, this invention modifies the molecular configuration of ethylenediamine by substituting hydrogen atoms in the carbon chain of alkyl groups, thereby altering its steric hindrance. This allows the alkyl group to act as a ligand for complexation with nickel salts, effectively controlling the oxidation state and coordination environment of nickel ions, thus improving the crystallinity and conductivity of the prepared nickel oxide film. Furthermore, the sol-gel spin-coating method ensures the nickel oxide film exhibits excellent uniformity, effectively preventing particle aggregation. Perovskite solar cells fabricated using the nickel oxide film prepared by this invention as a hole transport layer demonstrate superior photoelectric performance.

[0139] Based on the test results of Examples 1, 9, and 10, the molar ratio of nickel salt to ligand affects device performance. If the molar ratio of nickel salt is too high, the device efficiency will be severely degraded and the current density will be reduced. If the molar ratio of nickel salt is too low, the fill factor will decrease and the efficiency will be reduced.

[0140] Based on the test results of Example 1, Comparative Examples 1 and 2, compared with ethylenediamine or butanediamine with amino groups at both ends, the present invention substitutes hydrogens in the carbon chain of ethylenediamine, thereby changing the molecular configuration of ethylenediamine. When used as a ligand, it effectively regulates the oxidation state and coordination environment of nickel ions, thereby improving the crystallinity and conductivity of the prepared nickel oxide film and enhancing its photoelectric performance as a hole transport layer in perovskite solar cells.

[0141] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a nickel oxide thin film, characterized in that, The preparation method includes: Nickel salt and ligand are mixed to obtain a nickel complex; the nickel complex is dispersed in a solvent to obtain a sol-gel complex solution; the sol-gel complex solution is first spin-coated onto a substrate surface and then subjected to a first thermal annealing to prepare the nickel oxide film; The ligand has the chemical formula shown in Formula 1: Formula 1; R1 and R2 are each independently H, a chain alkyl group or a cycloalkyl group, and R1 and R2 are not both H.

2. The preparation method according to claim 1, characterized in that, In Formula 1, the chemical formula of the chain alkyl group is -C n H 2n+1 , 1≤n≤7; And / or, in Formula 1, the cycloalkyl group has the chemical formula -C m H 2m-1 , 4≤m≤6; And / or, in Formula 1, R1 and R2 are not both cycloalkyl.

3. The preparation method according to claim 1 or 2, characterized in that, The molar ratio of the nickel salt to the ligand is (1~1.5):1; And / or, the nickel salt includes any one or a combination of at least two of nickel nitrate, nickel sulfate, nickel acetate, or nickel chloride.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The solvent includes any one or a combination of at least two of ethylene glycol, propylene glycol, or isopropanol; And / or, in the sol-gel complex solution, the concentration of the nickel complex is 10 mg / mL to 30 mg / mL.

5. The preparation method according to any one of claims 1 to 4, characterized in that, The rotation speed of the first spin coating is 2500 rpm to 4500 rpm; And / or, the spin coating time is 20s~60s; And / or, the temperature of the first heat annealing is 200℃~400℃; And / or, the first heat annealing time is 0.5h to 2h.

6. The preparation method according to any one of claims 1 to 5, characterized in that, The preparation method further includes, after the first thermal annealing, a second thermal annealing is performed by spin-coating a [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid solution onto the surface of the nickel oxide film.

7. The preparation method according to claim 6, characterized in that, The concentration of the [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid solution is 0.3 mg / mL to 1 mg / mL; And / or, the solvent of the [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid solution includes isopropanol; And / or, the rotation speed of the second spin coating is 2500 rpm to 3500 rpm; And / or, the second spin coating time is 10s~30s; And / or, the temperature of the second heat annealing is 80°C to 120°C; And / or, the second heat annealing time is 8 min to 15 min.

8. A nickel oxide thin film, characterized in that, The nickel oxide thin film is prepared by the preparation method according to any one of claims 1 to 7.

9. A perovskite battery, characterized in that, The perovskite solar cell comprises a substrate, a hole transport layer, a perovskite active layer, a passivation layer, a functional layer, and a metal electrode, which are stacked sequentially. The hole transport layer is made of the nickel oxide thin film as described in claim 8.

10. The perovskite solar cell as described in claim 9, characterized in that, The material of the perovskite active layer includes Cs. x FA 1-x PbI3, 0 < x < 0.1; And / or, the material of the passivation layer includes meta-fluorine-substituted phenethylamine bromide and benzimidazole; And / or, the functional layer includes C 60 Functional layers and / or tin oxide functional layers; And / or, the metal electrode includes a gold electrode or a silver electrode; And / or, the substrate material includes any one of fluorine-doped tin oxide, indium-doped tin oxide, or aluminum-doped zinc oxide.

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