A preparation method, product and application of nickel oxide thin film

Abstract

The present invention discloses a method for preparing a nickel oxide thin film, its product and application, belonging to the technical field of photovoltaic materials and devices. The preparation method of the present invention includes: providing a homogeneous aqueous solution containing a nickel source compound and a basic amino acid, and chemically bath-depositing the homogeneous aqueous solution on the surface to be coated of a substrate, so that a nickel hydroxide film layer is formed in-situ on the surface to be coated, and then annealing the nickel hydroxide film layer to generate a nickel oxide thin film. By introducing a basic amino acid into the nickel source chemical bath aqueous solution for chemical bath deposition, the present invention can not only effectively and reasonably adjust the nucleation rate of nickel hydroxide by forming multi-dentate coordination with moderate strength between the basic amino acid and nickel ions, but also prevent the aggregation of nanoparticles through steric hindrance effect, effectively improving the dispersion effect of nanoparticles. Thus, the deposition behavior of nickel hydroxide nanoparticles is synergistically optimized in two aspects, and finally the controllable preparation of a nickel oxide thin film with uniform density and good crystallinity is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic materials and devices, and particularly relates to a preparation method, product and application of nickel oxide thin films. Background Art

[0002] Nickel oxide (NiO x ) has become the most commercially promising hole transport layer material for current perovskite solar cells due to its high hole mobility, low manufacturing cost and good stability. However, when preparing a nickel oxide hole transport layer by prefabricating nickel oxide nanoparticles through techniques such as spin coating, it is easy to cause uneven thickness, surface morphology defects and poor crystallinity of the prepared nickel oxide thin film, which is not conducive to the photoelectric conversion and stability of the battery. Therefore, the development of a method for preparing high-quality nickel oxide thin films has become a research hotspot.

[0003] Currently, it has been disclosed in the related art that nickel oxide thin films can be prepared by chemical bath deposition. For example, a preparation method of a nickel oxide thin film disclosed in a patent application with publication number CN115101682 A introduces ammonium ions into an alkaline nickel-containing chemical bath solution and forms a uniform and dense NiO x film through chemical bath deposition so that NiO x particles nucleate homogeneously.

[0004] However, there are still some deficiencies in the existing chemical bath deposition technology for preparing nickel oxide thin films. For example: (1) The selected ligands (such as ammonia water, ethanolamine, etc.) have relatively weak complexation with nickel ions, and the release of nickel ions during the nucleation process is uneven, so the nucleation uniformity of nickel oxide needs to be improved; (2) The ligand molecular structure is relatively small, and it is easy to cause agglomeration of nano nickel oxide particles, reducing the uniformity of the formed nickel oxide thin film; (3) The pH sensitivity is relatively low, which limits the controllability of the nickel oxide nucleation process. Summary of the Invention

[0005] The present invention effectively solves the above technical problems faced by the existing chemical bath deposition technology for preparing nickel oxide thin films by disclosing a preparation method, product and application of nickel oxide thin films.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a preparation method of a nickel oxide thin film. The preparation method of the nickel oxide thin film of the present invention includes:

[0008] Providing a homogeneous aqueous solution containing a nickel source compound and a basic amino acid;

[0009] Bringing the homogeneous aqueous solution into contact with the layer to be coated on the substrate and carrying out a chemical bath deposition reaction, so that a nickel hydroxide film layer is in-situ formed on the layer to be coated;

[0010] Anneal the nickel hydroxide film layer to obtain a nickel oxide thin film;

[0011] Among them, the nickel source compound is selected from at least one of nickel sulfate, nickel nitrate, nickel chloride, nickel carbonate, nickel acetylacetonate; and the basic amino acid is selected from at least one of histidine, arginine, and lysine.

[0012] According to the preparation method disclosed in the present invention, the temperature of the chemical bath deposition reaction is 50 - 80 °C, and the time is 60 - 180 min.

[0013] According to the preparation method disclosed in the present invention, the molar concentration of the nickel source compound is 0.001 - 0.5 mol / L, and the molar ratio of the nickel source compound to the basic amino acid is (1.5 - 2.5):1.

[0014] According to the preparation method disclosed in the present invention, the temperature of the annealing treatment is 270 - 360 °C, and the time is 60 - 180 min.

[0015] According to the preparation method disclosed in the present invention, the substrate is one of an FTO substrate and an ITO substrate.

[0016] In a second aspect, the present invention also provides a nickel oxide thin film made by the preparation method of the present invention, with a thickness of 10 - 20 nm.

[0017] In a third aspect, the present invention also provides an application of a nickel oxide thin film made by the preparation method of the present invention in a hole transport layer of a perovskite solar cell.

[0018] In a fourth aspect, the present invention also provides a perovskite solar cell, the structure of which includes a substrate and a hole transport layer, a perovskite active layer, an interface passivation layer, an electron transport layer, and a metal electrode sequentially arranged on the substrate. Among them, the hole transport layer includes a nickel oxide thin film made by the preparation method of the present invention.

[0019] Compared with the prior art, the advantages or beneficial effects of the embodiments of the present invention at least include:

[0020] After preparing a nickel hydroxide film layer by chemical bath deposition by introducing a basic amino acid into an aqueous nickel source chemical bath solution, high-temperature annealing is carried out to transform the nickel hydroxide film layer into a uniform, dense, and well-crystallized nickel oxide thin film. Specifically, the basic amino acid can form multi-dentate coordination with moderate strength with nickel ions, effectively and reasonably regulating the nucleation rate of nickel hydroxide, making the generated nickel hydroxide nanoparticles more uniform and finer. Moreover, the basic amino acid can also prevent the aggregation of the generated nanoparticles through steric hindrance effects, effectively improving the dispersion effect of the nanoparticles. Thus, through the synergistic optimization of the deposition behavior of nickel hydroxide nanoparticles in the above two aspects, the preparation of a uniform, dense, and well-crystallized nickel oxide thin film is achieved. In addition, the coordination ability of the basic amino acid has pH responsiveness, so the formation and decomposition of the complex can be controlled by adjusting the pH value of the solution, and it is expected to achieve precise regulation of the nucleation process of nickel hydroxide. Description of the Drawings

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 SEM images of the hole transport layer substrates obtained from the examples and comparative examples provided by the present invention x SEM images of the hole transport layer substrates;

[0023] Figure 2 XRD spectra of the hole transport layer substrates obtained from the examples and comparative examples provided by the present invention x XRD spectra of the hole transport layer substrates;

[0024] Figure 3 Schematic structural diagram of the perovskite solar cell device prepared in the example provided by the present invention;

[0025] Figure 4 Current-voltage characteristic curves of the perovskite solar cell devices manufactured in each example provided by the present invention;

[0026] Figure 5 Photovoltaic conversion efficiency distribution diagrams of the perovskite solar cell devices manufactured in each example provided by the present invention;

[0027] Figure 6 Stability test curves of the perovskite solar cell devices manufactured in each example provided by the present invention;

[0028] Figure 7 Relationship diagram of the influence of the molar ratio of nickel source to lysine on the performance provided by the present invention. Detailed Embodiments

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0030] In the following description of this specification, the term "and / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: the case of A existing alone, B existing alone, and A and B existing simultaneously. Wherein A and B may be singular or plural.

[0031] In the following description of this specification, the term "at least one" means one or more; "a plurality" means two or more. "At least one (item)" or similar descriptions thereof all refer to any combination of these items, including any combination of single items (pieces) or plural items (pieces). For example, "at least one (item) of A, B, or C", or, "at least one (item) of A, B, and C" both represent one of A, B, and C, or A + B, or A + C, or B + C, or A + B + C, wherein A, B, and C can be single or plural respectively.

[0032] In the following description of this specification, the sequence numbers do not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be specifically determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0033] In the following description of this specification, the numerical range should be understood as specifically disclosing each intermediate value between the upper and lower limits of the range. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0034] Unless otherwise specified, the technical / scientific terms used in this specification have the same meaning as commonly understood by those of ordinary skill in the art. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to the present invention can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the incorporated documents. In case of conflict with any incorporated document, the content of the present invention shall prevail.

[0035] In a first aspect, the present invention provides a method for preparing a nickel oxide thin film, the steps of which include:

[0036] Providing a homogeneous aqueous solution containing a nickel source compound and a basic amino acid;

[0037] Bringing the homogeneous aqueous solution into contact with the layer to be coated on the substrate and carrying out a chemical bath deposition reaction, so that a nickel hydroxide film layer is in-situ formed on the layer to be coated;

[0038] Annealing the nickel hydroxide film layer to obtain the nickel oxide thin film;

[0039] Wherein, the nickel source compound is selected from at least one of nickel sulfate, nickel nitrate, nickel chloride, nickel carbonate, nickel acetylacetonate; and, the basic amino acid is selected from at least one of histidine, arginine and lysine.

[0040] After the present invention prepares a nickel hydroxide film layer by introducing the above-mentioned basic amino acid into an aqueous solution of a nickel source chemical bath through chemical bath deposition, and then undergoes high-temperature annealing to convert the nickel hydroxide film layer into a nickel oxide thin film through a technical strategy. Among them, the basic amino acids selected in the present invention can exhibit at least the following advantages compared with the commonly used ligands such as ethanolamine and ammonia water in the prior art: (1) Basic amino acids can form multi-dentate coordination with moderate strength with nickel ions, so as to provide uniform and efficient release of nickel ions during the nucleation process, effectively regulating the nucleation rate of nickel hydroxide, making the generated nickel hydroxide nanoparticles more uniform and fine and having good crystallinity; (2) The unique side-chain structure of basic amino acids can provide a suitable steric hindrance effect, so as to prevent the aggregation of the generated nanoparticles and ensure the close arrangement of the nanoparticles through the steric hindrance effect, effectively improving the dispersion effect of the nanoparticles. The two aspects synergistically optimize the distribution and arrangement behavior of nickel hydroxide nanoparticles, achieving the preparation of a nickel oxide thin film with uniform density and good crystallinity; (3) Basic amino acids have unique pH responsiveness, so that their coordination behavior with nickel ions has pH responsiveness, and the formation and decomposition of the complex can be precisely controlled by adjusting the pH value of the solution, effectively achieving precise control of the nucleation process of nickel hydroxide.

[0041] It should be noted that the basic amino acid of the present invention is preferably lysine. Among them, by selecting histidine, arginine and / or lysine, the present invention, on the one hand, optimizes the coordination strength of the nickel-containing complex to achieve the effect of regulating the nucleation rate of nickel hydroxide, ensuring the generation of nickel hydroxide nanoparticles with small size and good uniformity; on the other hand, it provides a suitable steric hindrance to improve the dispersion effect of the nanoparticles, so as to achieve the environmentally friendly preparation of a nickel oxide thin film with uniform density and good crystallinity. Among them, the side chain of lysine is short and linear, which can ensure the dense distribution of the nanoparticles while providing a suitable steric hindrance effect to prevent the aggregation of the nanoparticles, making the prepared nickel oxide thin film have higher density.

[0042] According to an exemplary embodiment of the present disclosure, the temperature of the chemical bath deposition reaction of the present invention is 50 to 80 °C, and may be exemplified as 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, or any value within this range; the time is 60 to 180 min, and may be exemplified as 60 min, 90 min, 120 min, 150 min, 180 min, or any value within this range. Among them, by selecting the above chemical bath deposition parameters, the present invention can effectively optimize the deposition rate, crystallinity, and thickness, making the prepared nickel oxide thin film have uniform particles and good crystallinity.

[0043] According to an exemplary embodiment of the present disclosure, the molar concentration of the nickel source compound of the present invention is preferably 0.001 to 0.5 mol / L, and the molar ratio of the nickel source compound to the basic amino acid is preferably (1.5 to 2.5):1. In possible specific examples, the nickel source compound is 0.075 mol / L and the basic amino acid is 0.0375 mol / L. Among them, by selecting the above material ratio, the present invention can optimize the release rate of nickel ions, ensure the smooth progress of the deposition process, and make the prepared nickel oxide thin film have uniform particles and good crystallinity.

[0044] According to an exemplary embodiment of the present disclosure, the temperature of the annealing treatment of the present invention is preferably 270 to 360 °C, and may be exemplified as 270 °C, 280 °C, 290 °C, 300 °C, 320 °C, 350 °C, 360 °C, or any value within this range; the annealing time is 60 to 180 min, and may be exemplified as 60 min, 90 min, 120 min, 150 min, 180 min, or any value within this range. Among them, by selecting the above annealing parameters, the present invention can ensure the complete conversion of nickel hydroxide to nickel oxide and improve the purity quality of nickel oxide.

[0045] According to an exemplary embodiment of the present disclosure, the substrate of the present invention is preferably one of an FTO substrate and an ITO substrate. Among them, both the FTO substrate and the ITO substrate are understood in the general sense in the art. For example, the FTO substrate is fluorine-doped tin oxide, and its source can be commercially available.

[0046] In a second aspect, the present invention also discloses a nickel oxide thin film prepared by the preparation method of the present invention. Among them, the thickness of the nickel oxide thin film is 10 to 20 nm.

[0047] In a third aspect, the present invention also discloses an application of a nickel oxide thin film prepared by the preparation method of the present invention. Specifically, the nickel oxide thin film of the present invention is used as a hole transport layer in a perovskite solar cell. Among them, since the preparation method of the present invention can optimize the nucleation performance and dispersion effect of the prepared nickel oxide thin film, the nickel oxide thin film is denser and more uniform. Therefore, when the nickel oxide thin film of the invention is used as the hole transport layer in the perovskite solar cell, the conversion efficiency and stability of the battery can be effectively improved.

[0048] In a fourth aspect, the present invention also provides a perovskite solar cell, the structural composition of which includes a substrate and a hole transport layer, a perovskite active layer, an interface passivation layer, an electron transport layer, and a metal electrode sequentially disposed on the substrate. Among them, the hole transport layer is selected as the nickel oxide thin film of the present invention.

[0049] It should be noted that the present invention has no special limitation on the other functional layer materials and their preparation in the perovskite solar cell, and they can be made by the functional layer materials and general preparation strategies known in the art. For example, the substrate is FTO conductive glass, etc.

[0050] The technical solution of the present invention will be further described below in conjunction with specific embodiments.

[0051] Example 1

[0052] This example provides the preparation of a perovskite solar cell device, and the specific process includes:

[0053] S1 - Substrate cleaning: Put the FTO conductive glass ( ) into a clean petri dish, ultrasonically clean it with deionized water for 25 min (2 times); and, after ultrasonically cleaning it with ethanol for 25 min (2 times), dry it with a nitrogen gun and set it aside.

[0054] S2 - Hole transport layer deposition: Place the clean FTO substrate horizontally in a homogeneous aqueous solution containing 0.075 mol / L nickel sulfate and 0.0375 mol / L lysine (add ammonia water to adjust the pH of the homogeneous aqueous solution to ≈8), and place the homogeneous aqueous solution in an oven at 80 °C for chemical bath deposition for 120 min. After the chemical bath deposition is completed, first ultrasonically clean it in ultrapure water for 1 min, then use a nitrogen gun to blow off the excess water, and finally anneal it on a hot stage at 285 °C for 120 min to obtain a NiO x Hole transport layer substrate;

[0055] Drop 50 μL of a 0.5 mg / mL Me - 4PACz solution dissolved in ethanol on the NiO xSpin-coated into a film on the hole transport layer substrate. Among them, the spin-coating procedure is as follows: the acceleration is 4500 rpm / s, accelerate to 4500 rpm and spin-coat for 30 s. After the procedure stops, place the obtained wet film on a hot plate at 100 °C for heat annealing for 10 min, then cool to prepare the hole transport layer.

[0056] S3 - Perovskite active - passivation layer preparation: Take 40 μL of the prepared 1.5 M Cs 0.1 FA 0.9 PbI3 perovskite precursor solution (PbI2 is in excess by 8% and 15% MACl is added as an additive). Drop it on the hole transport layer and spin - coat into a film. Among them, the spin - coating procedure is as follows: the acceleration is 1000 rpm / s, accelerate to 5000 rpm and spin - coat for 35 s. At the 7th second from the end of the procedure, drop 180 μL of chlorobenzene as an anti - solvent. After the procedure stops, place the obtained wet film on a hot plate at 105 °C for heat annealing for 20 min, then cool to prepare the perovskite active layer. Drop 100 μL of the isopropanol solution of 1 mg / ml phenethylamine iodide on the perovskite active layer and spin - coat into a film. Among them, the spin - coating procedure is as follows: the acceleration is 5000 rpm / s, accelerate to 5000 rpm and spin - coat for 30 s. After the procedure stops, place the obtained wet film on a hot plate at 100 °C for heat annealing for 5 min, then cool to prepare the perovskite active - passivation layer.

[0057] S4 - Electron transport layer preparation: Under a vacuum of, vacuum evaporate 30 nm of C at an evaporation rate of 0.2 Å / s 60 and 8 nm of BCP on the 100 nm interfacial passivation layer to prepare the electron transport layer.

[0058] S5 - Metal electrode preparation: Under a vacuum of, vacuum evaporate a 100 nm silver electrode on the electron transport layer at a rate of 0.3 Å / s to obtain the perovskite solar cell device.

[0059] Example 2

[0060] This example provides the preparation of a perovskite solar cell device, and the specific process includes:

[0061] S1 - Substrate cleaning: Put the FTO conductive glass ( ) into a clean petri dish, ultrasonically clean it with deionized water for 25 min (2 times); and, ultrasonically clean it with ethanol for 25 min (2 times), then dry it with a nitrogen gun for standby.

[0062] S2 - Hole transport layer deposition: Place a clean FTO substrate horizontally in a homogeneous aqueous solution containing 0.075 mol / L nickel sulfate and 0.0375 mol / L arginine (adjust the pH of the homogeneous aqueous solution to approximately 8 by adding ammonia water), and place the homogeneous aqueous solution in an oven at 80 °C for chemical bath deposition for 120 min. After the chemical bath deposition, first place it in ultrapure water and sonicate for 1 min, then use a nitrogen gun to blow off the excess moisture, and finally anneal on a hot plate at 285 °C for 120 min to obtain NiO. x Hole transport layer substrate;

[0063] Drop 50 μL of 0.5 mg / mL Me - 4PACz solution dissolved in ethanol onto this NiO x hole transport layer substrate and spin - coat to form a film. Among them, the spin - coating procedure is as follows: acceleration 4500 rpm / s, accelerate to 4500 rpm and spin - coat for 30 s. After the program stops, place the obtained wet film on a hot plate at 100 °C for heating and annealing for 10 min, then cool to prepare the hole transport layer.

[0064] S3 - Perovskite active - passivation layer preparation: Take 40 μL of the prepared 1.5 M Cs 0.1 FA 0.9 PbI3 perovskite precursor solution (PbI2 is in excess by 8% and 15% MACl is added as an additive). Drop it onto the hole transport layer and spin - coat to form a film. Among them, the spin - coating procedure is as follows: acceleration 1000 rpm / s, accelerate to 5000 rpm and spin - coat for 35 s. At the 7th second from the end of the program, drop 180 μL of chlorobenzene as an anti - solvent. After the program stops, place the obtained wet film on a hot plate at 105 °C for heating and annealing for 20 min, then cool to prepare the perovskite active layer. Drop 100 μL of 1 mg / ml isopropanol solution of phenethylamine iodide onto the perovskite active layer and spin - coat to form a film. Among them, the spin - coating procedure is as follows: acceleration 5000 rpm / s, accelerate to 5000 rpm and spin - coat for 30 s. After the program stops, place the obtained wet film on a hot plate at 100 °C for heating and annealing for 5 min, then cool to prepare the perovskite active - passivation layer.

[0065] S4 - Electron transport layer preparation: Under a vacuum of..., vacuum evaporate 30 nm of C 60 and 8 nm of BCP on a 100 nm interfacial passivation layer to prepare the electron transport layer.

[0066] S5 - Metal electrode preparation: Under a vacuum of..., vacuum evaporate a 100 nm silver electrode on the electron transport layer to obtain the perovskite solar cell device.

[0067] Example 3

[0068] This example provides a preparation method of a perovskite solar cell device, and the specific process includes:

[0069] S1 - Substrate cleaning: Put the FTO conductive glass ( ) into a clean petri dish, ultrasonically clean it with deionized water for 25 min (twice); and, after ultrasonically cleaning it with ethanol for 25 min (twice), dry it with a nitrogen gun for standby.

[0070] S2 - Hole transport layer deposition: Place the clean FTO substrate horizontally in a homogeneous aqueous solution containing 0.075 mol / L nickel sulfate and 0.0375 mol / L histidine (add ammonia water to adjust the pH of the homogeneous aqueous solution to about 8), and place the homogeneous aqueous solution in an oven at 80 °C for chemical bath deposition for 120 min. After the chemical bath deposition is completed, first ultrasonically clean it in ultrapure water for 1 min, then use a nitrogen gun to blow off the excess water, and finally anneal it on a hot stage at 285 °C for 120 min to obtain a NiO x hole transport layer substrate;

[0071] Drop 50 μL of 0.5 mg / mL Me - 4PACz solution dissolved in ethanol on the NiO x hole transport layer substrate and spin - coat to form a film. Among them, the spin - coating program is: acceleration 4500 rpm / s, accelerate to 4500 rpm and spin - coat for 30 s. After the program stops, place the obtained wet film on a hot stage at 100 °C for heat annealing for 10 min, and then cool it to prepare a hole transport layer.

[0072] S3 - Perovskite active - passivation layer preparation: Take 40 μL of the prepared 1.5 M Cs 0.1 FA 0.9 PbI3 perovskite precursor solution (PbI2 is in excess by 8% and 15% MACl is added as an additive). Drop it on the hole transport layer and spin - coat to form a film. Among them, the spin - coating program is: acceleration 1000 rpm / s, accelerate to 5000 rpm and spin - coat for 35 s. At the 7th second from the end of the program, drop 180 μL of chlorobenzene as an anti - solvent. After the program stops, place the obtained wet film on a hot stage at 105 °C for heat annealing for 20 min, and then cool it to prepare a perovskite active layer. Drop 100 μL of 1 mg / ml isopropanol solution of phenethylamine iodide on the perovskite active layer and spin - coat to form a film. Among them, the spin - coating program is: acceleration 5000 rpm / s, accelerate to 5000 rpm and spin - coat for 30 s. After the program stops, place the obtained wet film on a hot stage at 100 °C for heat annealing for 5 min, and then cool it to prepare a perovskite active - passivation layer.

[0073] S4 - Electron transport layer preparation: Under a vacuum of, vacuum evaporate 30 nm of C at an evaporation rate of 0.2 Å / s 60 and 8 nm of BCP on a 100 nm interfacial passivation layer to prepare an electron transport layer.

[0074] S5 - Metal electrode preparation: Under a vacuum of, vacuum evaporate a 100 nm silver electrode on the electron transport layer at a rate of 0.3 Å / s to obtain a perovskite solar cell device.

[0075] To clarify the structural properties of the NiO x hole transport layer substrate prepared in the embodiments of the present invention, the present invention provides Comparative Examples 1 - 2 and explains them in combination with the following test results.

[0076] Comparative Example 1

[0077] The difference between this comparative example and Example 1 is that only lysine is replaced with ethanolamine, and ammonia water is added to adjust the pH of the homogeneous aqueous solution to approximately 8, and the rest are the same.

[0078] Comparative Example 2

[0079] The difference between this comparative example and Example 1 is that only lysine is replaced with ammonium chloride, and ammonia water is added to adjust the pH of the homogeneous aqueous solution to approximately 8, and the rest are the same.

[0080] Test Example 1

[0081] For easy distinction, the NiO x hole transport layer substrate prepared in Example 1 is abbreviated as NiO x -Lys, and the corresponding perovskite solar cell is abbreviated as PSCs-NiO x -Lys; the NiO x hole transport layer substrate prepared in Example 2 is abbreviated as NiO x -Arg, and the corresponding perovskite solar cell is abbreviated as PSCs-NiO x -Arg; the NiO x hole transport layer substrate prepared in Example 3 is abbreviated as NiO x -His, and the corresponding perovskite solar cell is abbreviated as PSCs-NiO x -His; the NiO x hole transport layer substrate prepared in Comparative Example 1 is abbreviated as NiO x -ETA, and the corresponding perovskite solar cell is abbreviated as PSCs-NiO x -ETA; the NiO x hole transport layer substrate prepared in Comparative Example 2 is abbreviated as NiO x-NH4 + , and the corresponding perovskite solar cell is abbreviated as PSCs-NiO x -NH4 + .

[0082] 1. SEM characterization.

[0083] The NiO x hole transport layer substrates prepared in the examples and comparative examples were characterized by scanning electron microscopy (SEM), and the results are Figure 1 shown. Among them, Figure 1 is the SEM image of the NiO x hole transport layer substrates obtained in the examples and comparative examples.

[0084] According to Figure 1 , when lysine, arginine, and histidine were introduced in the above examples, the compactness and uniformity of the prepared nickel oxide thin film were better than those of Comparative Example 1 and Comparative Example 2. In particular, introducing lysine can obtain a nickel oxide thin film with better uniformity, compactness, and conformal coverage. The reason may be that the side chain of lysine is short and linear, providing steric hindrance while not greatly affecting its compactness.

[0085] 2. XRD characterization

[0086] The NiO x hole transport layer substrates obtained in the examples and comparative examples were subjected to X-ray diffraction (XRD), and the results are Figure 2 shown. Among them, Figure 2 is the XRD spectrum of the NiO x hole transport layer substrates obtained in the examples and comparative examples.

[0087] According to Figure 2 , when lysine, arginine, and histidine were introduced, the compactness and uniformity of the obtained nickel oxide thin film were better than those of Comparative Example 1 and Comparative Example 2. In particular, when lysine was introduced, a nickel oxide thin film with smaller size, more uniform particle size, and conformal coverage was obtained, and it was in more sufficient contact with oxygen during the annealing process, so the obtained nickel oxide thin film had better crystallinity.

[0088] 3. Photovoltaic performance characterization

[0089] A 0.1 mm thick metal sheet with a perforated area of 0.059 cm 2 was used as a light-shielding template, and the photovoltaic performance of the perovskite solar cell devices manufactured in the examples and comparative examples of the present invention was tested under AM 1.5 G illumination provided by a 3A-class solar simulator. The results are Figures 3 - 5 shown. Among them, Figure 3 is the structural schematic diagram of the perovskite solar cell device prepared in the example; Figure 4Current-voltage characteristic curves of perovskite solar cell devices fabricated for each example; Figure 5 Photovoltaic conversion efficiency distribution maps of perovskite solar cell devices fabricated for each example.

[0090] According to Figure 3 it can be seen that the thickness of the nickel oxide thin film prepared by the chemical bath deposition method is 10 - 20 nm.

[0091] According to Figure 4, it can be seen that the device performance of the nickel oxide thin films incorporating basic amino acids in Examples 1 - 3 is generally higher than that of Comparative Example 1 and Comparative Example 2. Among them, the photovoltaic conversion efficiency of Example 1 is 25.55%; the photovoltaic conversion efficiency of Example 2 is 25.12%; the photovoltaic conversion efficiency of Example 3 is 25.18%.

[0092] According to Figure 5 it can be seen that statistical analysis from 6 independently prepared samples within the same batch shows that the highest average photovoltaic conversion efficiency of the devices in Example 1 is 25.37%; the average photovoltaic conversion efficiency of the devices in Example 2 is 25.09%; the average photovoltaic conversion efficiency of the devices in Example 3 is 25.07%; the average photovoltaic conversion efficiency of the devices in Comparative Example 1 is 24.42%; the average photovoltaic conversion efficiency of the devices in Comparative Example 2 is 22.29%, indicating that the photovoltaic conversion efficiency and repeatability of the devices prepared using basic amino acids, especially lysine as a ligand, to obtain nickel oxide thin films are higher than those of Comparative Example 1 and Comparative Example 2. The reason may be that introducing lysine can obtain a nickel oxide thin film with more uniform particle size, denser morphology, and better crystallinity, and these advantages are more conducive to the subsequent deposition of the perovskite layer, thereby obtaining devices with higher photovoltaic conversion efficiency.

[0093] 4. Stability test

[0094] In an environmental chamber, an accelerated aging test was carried out at a humidity of 35 ± 5% and a temperature of 60 °C, and the results are Figure 6 as shown. Among them, Figure 6 are the stability test curves of perovskite solar cell devices fabricated for each example.

[0095] According to Figure 6It can be seen that, compared with Comparative Example 1 and Comparative Example 2, the device prepared from the nickel oxide thin film obtained by introducing basic amino acids can maintain better damp heat stability while achieving a higher photoelectric conversion efficiency. Among them, the nickel oxide thin film obtained by introducing lysine in Example 1 has the best stability, and its photoelectric conversion efficiency remains 95.1% of the initial efficiency after 1500 hours of aging test; in Example 2, its photoelectric conversion efficiency remains 93.5% of the initial efficiency after 1500 hours of aging test; in Example 3, its photoelectric conversion efficiency remains 92.2% of the initial efficiency after 1500 hours of aging test; in Comparative Example 1, its photoelectric conversion efficiency remains 80.4% of the initial efficiency after 1500 hours of aging test; in Comparative Example 2, its photoelectric conversion efficiency remains 62.1% of the initial efficiency after 1500 hours of aging test.

[0096] 5. Influence of the molar ratio of nickel source to basic amino acid on performance

[0097] While keeping other preparation conditions of Example 1 unchanged, using nickel sulfate as the nickel source and lysine as the ligand, the influence of the amount of nickel source and ligand on the photoelectric conversion efficiency was explored. Among them, Figure 7 Figure showing the relationship between the molar ratio of nickel source to lysine and performance influence.

[0098] According to Figure 7 It can be seen that when the molar ratio of nickel source to lysine is 2.0:1, the maximum photoelectric conversion efficiency is obtained, and the average photoelectric conversion efficiency is 25.35%. When the molar ratios of nickel source to lysine are 1.5:1, 1.75:1, 2.25:1, and 2.5:1 respectively, the obtained average photoelectric conversion efficiencies are 24.77%, 24.95%, 24.96%, and 24.81% respectively.

[0099] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments.

[0100] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the present invention; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the present invention.

Claims

1. A method for preparing a nickel oxide thin film, characterized by comprising: Providing a homogeneous aqueous solution containing a nickel source compound and a basic amino acid; Bringing the homogeneous aqueous solution into contact with the layer to be coated on the substrate and undergoing a chemical bath deposition reaction, so that a nickel hydroxide film layer is in-situ formed on the layer to be coated; Performing an annealing treatment on the nickel hydroxide film layer to obtain a nickel oxide thin film; Among them, The nickel source compound is selected from at least one of nickel sulfate, nickel nitrate, nickel chloride, nickel carbonate, nickel acetylacetonate; and the basic amino acid is selected from lysine, and the molar ratio of the nickel source compound to the basic amino acid is 2.0:

1.

2. The preparation method according to claim 1, characterized in that, The temperature of the chemical bath deposition reaction is 50-80 °C, and the time is 60-180 min.

3. The preparation method according to claim 1, characterized in that, The molar concentration of the nickel source compound is 0.001-0.5 mol / L.

4. The preparation method according to claim 1, characterized in that, The temperature of the annealing treatment is 270-360 °C, and the time is 60-180 min.

5. The preparation method according to claim 1, characterized in that, The substrate is one of an FTO substrate and an ITO substrate.

6. A nickel oxide thin film, characterized in that, Comprising being prepared by the preparation method according to any one of claims 1-5, and having a thickness of 10-20 nm.

7. Application of the nickel oxide thin film prepared by the preparation method according to any one of claims 1-5 in a hole transport layer of a perovskite solar cell.

8. A perovskite solar cell, comprising a substrate and, successively disposed on the substrate, a hole transport layer, a perovskite active layer, an interface passivation layer, an electron transport layer, and a metal electrode, characterized in that, The hole transport layer comprises a nickel oxide thin film prepared by the preparation method according to any one of claims 1-5.

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