A perovskite solar cell and its fabrication method

Abstract

The application discloses a perovskite solar cell and a preparation method thereof, and the perovskite solar cell comprises a transparent electrode, an electron transport layer, a perovskite layer, a passivation layer, a hole transport layer and a top electrode which are sequentially stacked. x The material of the hole transport layer is a carbazole organic small molecule modified NiO The application innovatively introduces a modified additive, aiming at functionalizing and modifying inorganic metal oxide nanoparticles. Through sufficient contact and bonding between the modified additive and the oxide nanoparticles, the surface hydroxyl of the oxide is effectively eliminated, the dispersibility of the oxide nanoparticles in a non-polar dispersion liquid is improved, the film forming quality of the inorganic nano-oxide film is improved, the effective separation and transmission of photo-generated charges are promoted, and the stability of the device structure is enhanced, so that a high-efficiency and stable perovskite photoelectric device is finally obtained.

Description

Technical Field

[0001] This invention relates to the field of solar cells, specifically to a perovskite solar cell and its fabrication method. Background Technology

[0002] A hole transport layer is a specific functional layer located in a device, primarily composed of materials capable of efficiently transporting holes (i.e., positively charged carriers). These materials typically possess high hole mobility, ensuring efficient and rapid hole transport within the device. In upright perovskite solar cell structures, the hole transport layer sits above the perovskite light-absorbing layer; its hydrophobicity and compactness serve as the first line of defense for the perovskite. Commonly used hole transport layers primarily employ organic materials, such as the small organic molecules Spiro-OMeTAD and NiTiCl (NiPc), and polymers like poly(triarylamine) (PTAA) and poly(3-hexylthiophene) (P3HT). These materials are not only expensive (e.g., Spiro-OMeTAD is 23 times the price of gold, and PTAA is 57 times the price of gold), but also typically require Li doping. + Co + Plasma is used to improve hole mobility, but the doping of inorganic ions often leads to a decrease in device stability. Therefore, nickel oxide, as a common metal oxide, possesses a high work function of up to 5.4 eV and a wide bandgap of 3.6 to 4.0 eV, exhibiting high transmittance in the near-ultraviolet and visible light range. From a chemical structure perspective, nickel oxide not only possesses excellent intrinsic stability but also exhibits highly efficient hole-carrying capability due to the presence of oxygen vacancies and high-valence nickel. Electronically, its energy levels are well-matched to perovskite absorber layers and offer the advantage of tunable energy levels. In terms of fabrication, nickel oxide has relatively low raw material costs, mature fabrication processes, and its high transmittance lays the foundation for subsequent fabrication of bifacial perovskite solar cells. In summary, nickel oxide, as a hole transport layer, not only achieves high efficiency in small-area devices but also lays the foundation for fabricating efficient and stable modules, demonstrating significant industrialization potential and thus becoming one of the best candidates for highly stable inorganic hole transport materials.

[0003] Currently, the research focus of upright perovskite solar cells is highly concentrated on optimizing NiO. xThe dispersion efficiency of nanocrystals in nonpolar solvent systems must be assessed, while simultaneously ensuring that the selected solvent does not damage the perovskite layer structure. Since the dispersion state of hole materials in the solvent directly affects the quality of the film formed on the perovskite surface, constructing a dense and pinhole-free hole transport layer is crucial. Such a structure can effectively isolate the electrode from direct contact with the perovskite, thereby improving photoelectric conversion efficiency. Although ligand engineering strategies have been developed to enhance the dispersibility of hydrophilic nickel oxide in nonpolar solvents, this approach also presents significant challenges. Previous reports (ACS Applied Energy Materials 2019, 2, 4890) have used oleic acid and oleylamine as ligands to improve the dispersibility of nickel oxide in nonpolar solvents. However, the use of long-chain ligands often leads to excessive steric hindrance in charge transport between particles, which adversely affects photoelectric performance. The additive used to modify hydrophilic nickel oxide in CN117682772A contains hydrophobic groups. The modified additive includes at least one of alkylamine compounds, alkyl acid compounds, and alkyl thiols. Although this method increases the dispersibility of hydrophilic nickel oxide in nonpolar solvents to some extent, the introduced ligands are long-chain alkyl compounds, which have the disadvantages of large steric hindrance and non-conductivity, thus limiting the efficiency improvement of perovskite solar cells.

[0004] For perovskite optoelectronic devices, especially upright devices, achieving a tightly ordered assembly of inorganic nanoparticles on the perovskite surface is undoubtedly a highly challenging task. Although introducing oleophilic ligands can significantly improve the dispersibility of nanoparticles in nonpolar solvents, thus achieving uniform and tight coverage of the perovskite film, several problems remain to be solved. First, while excessive use of long-chain ligands (such as oleic acid, oleylamine, stearic acid, etc.) can improve dispersibility, it severely hinders charge transport, further weakening hole transport capability and affecting the overall device performance. This is a significant issue, as hole transport capability is crucial for the performance of upright devices. Second, excessive introduction of these long-chain ligands also raises another complex problem: requiring an additional secondary cleaning step to remove excess ligands and reduce their adverse effects on charge transport. This not only increases the complexity of the fabrication process but also significantly increases wastewater treatment costs, placing a burden on the environment. Furthermore, the yield of oily nanomaterials in a single synthesis is often low, posing another challenge: how to mass-produce nickel oxide nanoparticle dispersions suitable for upright structures. This challenge is not only about cost, but also about whether large-scale production and commercial application can be achieved.

[0005] Currently, to facilitate subsequent industrialization, hydrophilic nickel oxide is proposed as the raw material for inorganic holes. Its production cost is low, and the preparation and synthesis process is relatively simple. However, considering that the orthogonal hole layer is located above the perovskite light-absorbing layer, polar solvents such as chlorobenzene are required for dispersion. Therefore, the hydrophilic nickel oxide needs to be modified to improve its dispersibility in non-polar solvents. Thus, single-ligand and dual-ligand strategies are considered. Introducing long-chain carbon improves the dispersibility of nickel oxide in non-polar solvents, thereby improving the film-forming properties of the nickel oxide hole transport layer. Only a dense, pinhole-free hole transport layer can prevent contact between the electrode and the perovskite, thereby achieving high photoelectric conversion efficiency. However, traditional ligand modification methods have the following problems:

[0006] 1. Poor thermal stability: Organic ligands such as oleylamine and octylamine (oleylamine boiling point is 364℃, octylamine boiling point is 175℃) may decompose or desorb under high temperature conditions, leading to a weakening or failure of the modification effect. This is a limiting factor for the application of materials that require high-temperature treatment.

[0007] 2. Uneven surface coverage: In some cases, ligand modification of oleylamine or octylamine may lead to uneven or incomplete surface coverage, which can affect the performance consistency and repeatability of the material.

[0008] 3. Ligand desorption: Due to the limited adsorption capacity of oleylamine and octylamine on the nickel oxide surface, they are prone to desorption, resulting in a decrease in dispersion stability.

[0009] 4. Process complexity: The ligand modification process may require precise control of reaction conditions, such as temperature, time and the amount of ligand used, which increases the complexity and cost of the process.

[0010] 5. Effects on photoelectric properties: Organic ligands are insulating materials. Excessive introduction will introduce steric hindrance, affecting charge transport between nanomaterials.

[0011] Therefore, a novel technology is urgently needed that combines the ability to enhance the dispersibility of hydrophilic nickel oxide in nonpolar solvents with the ability to improve hole mobility, in order to comprehensively optimize the performance of upright nickel oxide hole transport layer devices. This proposal innovatively introduces the organic small molecule SAM (Self-Assembled Monolayer) as a hole material dopant, significantly improving the performance of NiO. x Uniform dispersion of NiO in nonpolar solvents. By finely controlling the interaction between SAM and the mixed solvent, it is possible not only to achieve uniform dispersion of NiO... xThe efficient dispersion of nanoparticles further improves the film quality, ensuring the compactness and pinhole-free characteristics of the hole transport layer. This method effectively replaces traditional ligand engineering, thus avoiding the problems of increased steric hindrance and impaired hole transport performance caused by the introduction of long carbon chain ligands, and opening up new avenues for improving the performance of perovskite solar cells. Summary of the Invention

[0012] To overcome the shortcomings of the prior art, the present invention provides a perovskite solar cell and a method for its fabrication.

[0013] A first aspect of the present invention provides a perovskite solar cell, the perovskite solar cell comprising a transparent electrode, an electron transport layer, a perovskite layer, a passivation layer, a hole transport layer and a top electrode stacked sequentially.

[0014] The hole transport layer is made of NiO modified with carbazole-based small organic molecules. x The passivation layer is made of carbazole-based small organic molecules.

[0015] According to the perovskite solar cell of the first aspect, wherein the carbazole-based organic small molecule is selected from one or more of Me-4PACz, MeO-2PACz, and 2PACz; and / or

[0016] The NiO x It is a hydrophilic nickel oxide.

[0017] According to the first aspect of the perovskite solar cell, wherein, in the hole transport layer, carbazole-based organic small molecules and NiO... x The mass ratio is 1:(25~50).

[0018] According to the first aspect of the perovskite solar cell, wherein the perovskite solar cell is a positively charged solar cell;

[0019] Preferably, the upright solar cell includes a substrate containing transparent electrodes;

[0020] More preferably, an interface modification layer is further provided between the hole transport layer and the top electrode.

[0021] According to the first aspect of the perovskite solar cell, the substrate is an FTO substrate or an ITO substrate, preferably an FTO substrate; the electron transport layer material is selected from one or more of ZnO, TiO2, SnO2, and ZnTiO3, preferably SnO2;

[0022] The perovskite layer material is selected from one or more of FAPbI3, MAPbI3, CsFAPbI3, and CsMAFAPbI3, preferably CsFAPbI3; and / or

[0023] The interface modification layer material is MoO3.

[0024] A second aspect of the present invention provides a method for fabricating a perovskite solar cell according to the first aspect, comprising fabricating a hole transport layer by means of:

[0025] Carbazole-based organic small molecules and NiO x Nanoparticles were dispersed in an aprotic polar solvent and ball-milled to obtain NiO. x The dispersion is coated with the NiO on the passivation layer. x The dispersion was dried to obtain a hole transport layer.

[0026] According to the method of the second aspect, wherein the NiO x The D50 of the nanoparticles is 5-60 nm, preferably 10 nm.

[0027] According to the method of the second aspect, the aprotic polar solvent is selected from one or more of chlorobenzene, chlorobenzene, chloroform, toluene, diethyl ether, and ethyl acetate, preferably chlorobenzene.

[0028] According to the method of the second aspect, the ball milling time is 5 to 12 hours, preferably 6 hours; and / or

[0029] The ball-to-material ratio of the ball mill is (20-30):1, preferably 25:1.

[0030] According to the method of the second aspect, wherein NiO is coated on the passivation layer x The dispersion step is carried out in an inert gas atmosphere.

[0031] The perovskite solar cell and its preparation method of the present invention have, but are not limited to, the following beneficial effects:

[0032] This invention utilizes carbazole-based small organic molecules to target NiO x Modification by introducing organic molecules not only promotes the dispersion of water-soluble nickel oxide in polar solvents such as chlorobenzene, but also eliminates hydroxyl groups on the nickel oxide surface, improving the stability of the hole transport layer. Introducing organic molecules into nickel oxide can adjust the energy levels of the hole transport layer, making it more compatible with the energy levels of the perovskite absorber layer, thereby reducing on-state voltage loss and improving device efficiency. Using small organic molecules (SAM) to enhance the dispersibility of hydrophilic nickel oxide in non-polar solvents, followed by spin-coating it onto the surface of the perovskite absorber layer, achieves passivation of the perovskite interface and preparation of the hole transport layer in one step, with a simple process. Attached Figure Description

[0033] Figure 1The effects of adding carbazole-based small organic molecule PACz on the hydrophilicity of NiO were shown. x The dispersion of nanoparticles in the nonpolar solvent chlorobenzene. Detailed Implementation

[0034] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present application will become clearer and more apparent.

[0035] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0036] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0037] This invention provides a perovskite solar cell, which includes a transparent electrode, an electron transport layer, a perovskite layer, a passivation layer, a hole transport layer, and a top electrode stacked sequentially.

[0038] The hole transport layer is made of NiO modified with carbazole-based small organic molecules. x The passivation layer is made of carbazole-based small organic molecules.

[0039] The carbazole-based organic molecules in the hole transport layer and the passivation layer can be the same or different.

[0040] In this invention, the NiO x Nickel oxide, also known as nickel oxide, is a variable-valence metal oxide that is sensitive to redox reactions and has a wide bandgap and good electrical conductivity.

[0041] hydrophilic NiO x Nickel oxide exhibits poor dispersibility and agglomeration in nonpolar solvents, hindering the formation of a dense and uniform hole transport layer. Currently, ligands in ligand-modified nickel oxide are primarily derived from long-chain carbons. While this improves the dispersibility of hydrophilic nickel oxide in nonpolar solvents like chlorobenzene, it also suffers from high steric hindrance and poor conductivity, thus impeding hole transport capabilities to some extent. The inventors have discovered that introducing organic molecules can not only promote the dispersion of water-soluble nickel oxide in nonpolar solvents like chlorobenzene, but also… Figure 1 As shown, before the addition of the carbazole-based small organic molecule PACz, the hydrophilic NiO x Nanoparticles aggregate in the nonpolar solvent chlorobenzene, which is detrimental to the preparation of hole transport layers. The addition of PACz greatly enhances the hydrophilicity of NiO. xThe dispersibility in chlorobenzene is improved, resulting in a uniform, stable, and well-dispersible hydrophilic NiO. x The chlorobenzene dispersion effectively overcomes the problem of poor assembly density of nickel oxide films caused by the ligand method. Simultaneously, the introduction of carbazole-based organic molecules can eliminate hydroxyl groups on the nickel oxide surface, enhancing the stability of the hole transport layer to some extent. Introducing organic molecules into nickel oxide can adjust the energy levels of the nickel oxide hole transport layer, making it more compatible with the energy levels of the perovskite absorber layer, optimizing the device's interface energy levels, improving hole transport and collection efficiency, and thus reducing on-state voltage loss, ultimately improving device efficiency.

[0042] Compared to long-chain carbon ligand modification strategies, introducing organic small molecules such as SAM can not only help disperse hydrophilic nickel oxide in nonpolar solvents, avoiding problems such as hindering charge transport, large steric hindrance, and poor volatility caused by long-chain carbon ligands, but also enhance the hole transport layer's hole capacity and prevent nickel oxide nanoparticle aggregation. This is because organic small molecule SAM itself can also act as a hole layer to extract holes, and it has extremely high hole extraction capacity.

[0043] In one embodiment, the carbazole organic small molecule is selected from one or more of Me-4PACz, MeO-2PACz, and 2PACz.

[0044] Therefore, organic small molecules SAM ([4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, and [2-(9H-carbazole-9-yl)ethyl]phosphonic acid, etc.) were introduced into nickel oxide dispersions. Experiments showed that organic molecules SAM can not only help hydrophilic nickel oxide disperse in nonpolar solvents, but also eliminate hydroxyl groups on the surface of nickel oxide to a certain extent, thereby improving device stability.

[0045]

[0046] [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphate (Me-4PACz) chemical structural formula

[0047]

[0048] [2-(3,6-Dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz) chemical structural formula

[0049]

[0050] [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz) chemical structure

[0051] As shown above, carbazole-based organic small molecules possess strong chemical stability and high oxidation potential. Simultaneously, phosphate groups can passivate the hydroxyl groups of nickel oxide nanoparticles. SAM molecules without passivated hydroxyl groups can also interact with perovskite, passivating defects on the surface of the perovskite light-absorbing layer. Furthermore, oxygen-containing carbazole derivatives exhibit stronger interfacial bonding energy with perovskite, primarily due to the interaction between oxygen with lone pair electrons and lead on the perovskite surface.

[0052] In one embodiment, the hole transport layer contains carbazole-based organic small molecules and NiO. x The mass ratio is 1:25 to 50.

[0053] In one embodiment, the perovskite solar cell is a positively charged solar cell;

[0054] Preferably, the upright solar cell includes a substrate containing transparent electrodes;

[0055] More preferably, an interface modification layer is further provided between the hole transport layer and the top electrode.

[0056] In one embodiment, the substrate is an FTO substrate or an ITO substrate, preferably an FTO substrate; the electron transport layer material is selected from one or more of ZnO, TiO2, SnO2, and ZnTiO3, preferably SnO2;

[0057] The perovskite layer material is selected from one or more of FAPbI3, MAPbI3, CsFAPbI3, and CsMAFAPbI3, preferably CsFAPbI3; and / or the interface modification layer material is MoO3.

[0058] The present invention also provides a method for fabricating the perovskite solar cell, comprising fabricating a hole transport layer by the following method:

[0059] Carbazole-based organic small molecules and NiO x Nanoparticles were dispersed in an aprotic polar solvent and ball-milled to obtain NiO. x The dispersion is coated with the NiO on the passivation layer. x The dispersion was dried to obtain a hole transport layer.

[0060] This invention uses a non-polar dispersion of aqueous nickel oxide prepared by dispersing organic small molecules SAM (carbazole-based organic small molecules), which is then spin-coated onto the surface of a perovskite light-absorbing layer, thereby achieving the purpose of passivating the perovskite surface and preparing a hole transport layer in one step.

[0061] The preparation method of this invention introduces a modifying additive for functionalizing inorganic metal oxide nanoparticles (i.e., metal oxide nanocrystals). Through dispersion treatment, the modifying additive fully contacts and bonds to the oxide surface with the oxide nanoparticles, eliminating hydroxyl groups on the oxide surface, increasing the dispersibility of the oxide in nonpolar solvents, and effectively reducing the aggregation of oxide nanoparticles. This process achieves stable dispersion of the oxide in aprotic polar solvents, thereby obtaining a uniform, stable, and well-dispersed oxide slurry. This oxide slurry can be directly applied to perovskite optoelectronic devices, improving the film-forming properties of inorganic nano-oxide films, and simultaneously enhancing the photoelectric conversion efficiency and stability of the prepared perovskite optoelectronic devices. In one embodiment, the NiO... x The D50 of the nanoparticles is 5–60 nm, preferably 10 nm. In one embodiment, the aprotic polar solvent is selected from one or more of chlorobenzene, chloroform, toluene, diethyl ether, and ethyl acetate, preferably chlorobenzene. In one embodiment, the ball milling time is 5–12 h, preferably 6 h; and / or the ball-to-material ratio of the ball milling is (20–30):1, preferably 25:1. In one embodiment, the NiO coating on the passivation layer… x The dispersion step is carried out in an inert gas atmosphere.

[0062] The preparation method of the present invention has the following effects:

[0063] 1. Assembly density:

[0064] When constructing a nickel oxide hole transport layer on a perovskite surface, ensuring the tight and uniform assembly of nanoparticles is crucial. This invention utilizes the synergistic regulation of SAM and ligands to effectively bond the nanoparticles to the nickel oxide nanocrystal surface, significantly reducing particle aggregation and optimizing its dispersion performance in nonpolar solvents. This not only greatly improves the assembly density of the nickel oxide hole transport layer on the perovskite surface but also enhances the stability and reliability of the device, laying a solid foundation for its high-efficiency optoelectronic performance.

[0065] 2. Hole transmission efficiency:

[0066] Hole transport efficiency is one of the key factors affecting the performance of upright devices. The SAM molecules in this invention not only possess excellent dispersion properties but also strong hole extraction capabilities. By passivating defects on the nickel oxide surface and optimizing the electronic structure of holes, combined with the intrinsic hole extraction capability of SAM molecules, the hole transport efficiency of the device is significantly improved. This is of great significance for improving the photoelectric conversion efficiency and stability of the device.

[0067] 3. Batch preparation:

[0068] While pursuing the fabrication of high-performance upright devices, batch fabrication technology is crucial. The SAM-ligand synergistic regulation strategy proposed in this invention not only optimizes nanoparticle dispersion and hole transport efficiency but also simplifies the fabrication process and reduces production costs. By optimizing fabrication parameters and processes, this invention achieves batch fabrication of nickel oxide hole transport layers, opening new avenues for large-scale production and commercial applications.

[0069] This invention addresses three major challenges in assembling nickel oxide hole transport layers on perovskite surfaces for positive-position devices: assembly compactness, hole transport efficiency, and mass production. By introducing a synergistic regulation strategy between SAM and ligands, this invention provides an effective solution for fabricating high-performance positive-position devices.

[0070] This invention does not impose any special restrictions on the source of any raw materials; unless otherwise specified, all are conventional products that can be obtained commercially. The NiO used in the following examples... x The nanoparticles are hydrophilic NiO x Nanoparticles.

[0071] Example 1:

[0072] Take 2 mg Me-4PACz and 100 mg NiO x Nanoparticles (i.e., metal oxide nanocrystals) and 2.5g of ball-milled beads were dispersed in 1mL of chlorobenzene and shaken at high speed for 6h in a shaker to obtain NiO. x Dispersion (i.e., oxide slurry);

[0073] Among them, the selected NiO x The nanoparticles (metal oxide nanocrystals) have a D50 of 10 nm.

[0074] The grinding balls are made by mixing grinding balls with a diameter of 0.1 mm and grinding balls with a diameter of 1 mm at a mass ratio of 3:1, with a total weight of 2.5 g.

[0075] Example 2:

[0076] Take 4 mg Me-4PACz and 100 mg NiO x Nanoparticles (i.e., metal oxide nanocrystals) and 2.5g of ball-milled beads were dispersed in 1mL of chlorobenzene and shaken at high speed for 6h in a shaker to obtain NiO. x Dispersion (i.e., oxide slurry);

[0077] Among them, the selected NiO x The nanoparticles (metal oxide nanocrystals) have a D50 of 10 nm.

[0078] The grinding balls are made by mixing grinding balls with a diameter of 0.1 mm and grinding balls with a diameter of 1 mm at a mass ratio of 3:1, with a total weight of 2.5 g.

[0079] Example 3:

[0080] Take 2 mg MeO-2PACz and 100 mg NiO x Nanoparticles (i.e., metal oxide nanocrystals) and 2.5g of ball-milled beads were dispersed in 1mL of chlorobenzene and shaken at high speed for 6h in a shaker to obtain NiO. x Dispersion (i.e., oxide slurry);

[0081] Among them, the selected NiO x The nanoparticles (metal oxide nanocrystals) have a D50 of 10 nm.

[0082] The grinding balls are made by mixing grinding balls with a diameter of 0.1 mm and grinding balls with a diameter of 1 mm at a mass ratio of 3:1, with a total weight of 2.5 g.

[0083] Example 4:

[0084] Take 4 mg MeO-2PACz and 100 mg NiO x Nanoparticles (i.e., metal oxide nanocrystals) and 2.5g of ball-milled beads were dispersed in 1mL of chlorobenzene and shaken at high speed for 6h in a shaker to obtain NiO. x Dispersion (i.e., oxide slurry);

[0085] Among them, the selected NiO x The nanoparticles (metal oxide nanocrystals) have a D50 of 10 nm.

[0086] The grinding balls are made by mixing grinding balls with a diameter of 0.1 mm and grinding balls with a diameter of 1 mm at a mass ratio of 3:1, with a total weight of 2.5 g.

[0087] Example 5:

[0088] Take 2 mg of 2PACz and 100 mg of NiO x Nanoparticles (i.e., metal oxide nanocrystals) and 2.5g of ball-milled beads were dispersed in 1mL of chlorobenzene and shaken at high speed for 6h in a shaker to obtain NiO. x Dispersion (i.e., oxide slurry); at

[0089] Among them, the selected NiO x The nanoparticles (metal oxide nanocrystals) have a D50 of 10 nm.

[0090] The grinding balls are made by mixing grinding balls with a diameter of 0.1 mm and grinding balls with a diameter of 1 mm at a mass ratio of 3:1, with a total weight of 2.5 g.

[0091] Example 6:

[0092] Take 4 mg of 2PACz and 100 mg of NiO x Nanoparticles (i.e., metal oxide nanocrystals) and 2.5g of ball-milled beads were dispersed in 1mL of chlorobenzene and shaken at high speed for 6h in a shaker to obtain NiO. x Dispersion (i.e., oxide slurry);

[0093] Among them, the selected NiO x The nanoparticles (metal oxide nanocrystals) have a D50 of 10 nm.

[0094] The grinding balls are made by mixing grinding balls with a diameter of 0.1 mm and grinding balls with a diameter of 1 mm at a mass ratio of 3:1, with a total weight of 2.5 g.

[0095] Comparative Example 1:

[0096] Take 10 μL of oleylamine (long carbon chain ligand) and 100 mg of NiO x Nanoparticles (i.e., metal oxide nanocrystals) and 2.5g of ball-milled beads were dispersed in 1mL of chlorobenzene and shaken at high speed for 6h in a shaker to obtain NiO. x Dispersion;

[0097] Among them, the selected NiO x The nanoparticles (metal oxide nanocrystals) have a D50 of 10 nm.

[0098] The grinding balls are selected from grinding balls with a diameter of 0.1 mm and grinding balls with a diameter of 1 mm in a mass ratio of 3:1, with a total weight of 2.5 g.

[0099] Comparative Example 2:

[0100] Take 2 mg Me-4PACz and 100 mg NiO x Nanoparticles (i.e., metal oxide nanocrystals) and 2.5g of ball-milled beads were dispersed in 1mL of chlorobenzene and shaken at high speed for 6h in a shaker to obtain NiO. x Dispersion;

[0101] Among them, the selected NiO x The nanoparticles (metal oxide nanocrystals) have a D50 of 10 nm.

[0102] The grinding balls are selected from grinding balls with a diameter of 0.1 mm and grinding balls with a diameter of 1 mm in a mass ratio of 3:1, with a total weight of 2.5 g.

[0103] During device fabrication, no SAM layer is added for passivation between the perovskite layer and the nickel oxide hole transport layer, resulting in a device structure of FTO / SnO2 / CsFAPbI3 / NiO.x The effect of having or not having a SAM molecular passivation layer on the overall performance of / MoO3 / Ag is compared.

[0104] Performance testing in the examples and comparative examples:

[0105] The oxide slurry obtained in the above examples and comparative examples was used to prepare a positive solar cell according to the following method:

[0106] NiO prepared according to the examples and comparative examples x The dispersion was used to fabricate a device with the following structure: FTO / SnO2 / CsFAPbI3 / SAM / NiO x / MoO3 / Ag perovskite solar cells.

[0107] The hole transport layer of this perovskite solar cell is a layer of NiO prepared by spin-coating the above-described embodiments and comparative examples. x It was prepared as a dispersion.

[0108] Specifically, FTO / SnO2 / CsFAPbI3 / SAM / NiO x The fabrication process of the / MoO3 / Ag perovskite solar cell is as follows:

[0109] (1) Fabrication of the electron transport layer:

[0110] An electron transport layer is spin-coated on a substrate containing a bottom electrode; wherein the substrate containing the bottom electrode is an FTO substrate, and the electron transport layer is SnO2. SnO2 with a particle size of 3-4 nm is dissolved in deionized water to obtain a solution with a concentration of 30 mg / mL. The solution is spin-coated at 2000 rpm for 30 s, annealed at 150 °C for 30 min, and then annealed at 60 °C for 30 min to obtain an electron transport layer with a thickness of 40 nm.

[0111] (2) A perovskite layer, namely the CsFAPbI3 layer, is deposited on the electron transport layer prepared in step (1). Specifically, lead iodide (PbI2), formamidine iodide (FAI), and cesium iodide (CsI) are dissolved in a mixed solution of N-methylpyrrolidone and N,N-dimethylformamide (the ratio of lead iodide, formamidine iodide, cesium iodide, N-methylpyrrolidone, and N,N-dimethylformamide is 461 mg:157 mg:15 mg:100 μL 600 μL). The solution is stirred for 2 h to obtain a perovskite precursor solution. Then, the perovskite precursor solution is spin-coated onto the SnO2 layer at 3000 rpm and annealed at 100 °C for 15 min to obtain the perovskite light-absorbing layer (CsFAPbI3 layer).

[0112] (3) Preparation of passivation layer (SAM layer): SAM dispersion was spin-coated onto the perovskite layer (FAPbI3 layer) prepared in step (2) at a speed of 5000 rpm to obtain the passivation layer;

[0113] The SAM dispersion was prepared by dissolving 1 mM of SAM molecules in 1 mL of isopropanol. In the performance testing of this invention, NiO prepared in the corresponding examples and comparative examples was used. x The same SAM molecules were used to prepare the passivation layer in Example 1, while Me-4PACz was used to prepare the passivation layer in Comparative Example 1.

[0114] (4) Preparation of hole transport layer: Under nitrogen glove box conditions, the NiO prepared in the examples and comparative examples was subjected to a rotation speed of 3000 rpm on the passivation layer obtained in step (3). x Spin-coating the dispersion and allowing the resulting substrate to air dry at room temperature yields a hole transport layer.

[0115] (5) A MoO3 layer (15 nm) is prepared on the hole transport layer obtained in step (4), and then a top electrode is deposited on the MoO3 layer by evaporation. The MoO3 layer can be prepared by: depositing a 15 nm MoO3 layer using a vacuum thermal evaporation coating apparatus at a deposition rate of [missing information].

[0116] The top electrode is Ag, and an Ag electrode (50nm) is deposited using a vapor deposition method; after the device vapor deposition is completed, it is encapsulated to obtain FTO / SnO2 / CsFAPbI3 / SAM / NiO. x Perovskite light-emitting devices based on / MoO3 / Ag.

[0117] The devices were prepared according to the above method and tested under the same test conditions (all device tests were conducted at room temperature and 40% humidity). The results are shown in Table 1 below:

[0118] Table 1

[0119]

[0120]

[0121]

[0122] The performance test results above show that Examples 1-6 used SAM molecules to counteract NiO. x The layer was modified, and hydrophilic NiO was successfully incorporated. xNanoparticles were uniformly dispersed in a nonpolar solvent to prepare a high-performance nickel oxide-based hole transport layer, improving the photoelectric performance and stability of the device. Compared with Comparative Example 1, which used the traditional long-chain carbon chain ligand oleylamine, and Comparative Example 2, which did not have a SAM passivation layer, Examples 1 and 2 both exhibited better photoelectric performance and stability. This indicates that the introduced small organic molecule SAM not only improves the dispersibility of hydrophilic nickel oxide in nonpolar solvents but also enhances the hole extraction capability of the hole transport layer, thereby resulting in superior photoelectric performance and stability.

[0123] The present application has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present application based on these embodiments, all of which fall within the protection scope of the present application.

Claims

1. A perovskite solar cell, characterized in that, The perovskite solar cell comprises a transparent electrode, an electron transport layer, a perovskite layer, a passivation layer, a hole transport layer, and a top electrode, which are stacked sequentially. The hole transport layer is made of NiO modified with carbazole-based small organic molecules. x The passivation layer is made of carbazole-based small organic molecules. The carbazole-based small organic molecules are selected from one or more of Me-4PACz, MeO-2PACz, and 2PACz; The NiO x It is a hydrophilic nickel oxide; In the hole transport layer, carbazole-based organic small molecules and NiO x The mass ratio is 1:(25~50).

2. The perovskite solar cell according to claim 1, characterized in that, The perovskite solar cell is a positively mounted solar cell.

3. The perovskite solar cell according to claim 2, characterized in that, The upright solar cell includes a substrate containing the transparent electrode.

4. The perovskite solar cell according to claim 3, characterized in that, An interface modification layer is also provided between the hole transport layer and the top electrode.

5. The perovskite solar cell according to claim 4, characterized in that, The substrate is an FTO substrate or an ITO substrate; the electron transport layer material is selected from one or more of ZnO, TiO2, SnO2, and ZnTiO3. The perovskite layer material is selected from one or more of FAPbI3, MAPbI3, CsFAPbI3, and CsMAFAPbI3; and / or The interface modification layer material is MoO3.

6. The perovskite solar cell according to claim 5, characterized in that, The substrate is an FTO substrate; The electron transport layer material is SnO2; The perovskite layer material is CsFAPbI3.

7. A method for fabricating a perovskite solar cell according to any one of claims 1 to 6, comprising fabricating a hole transport layer by the following method: Carbazole-based organic small molecules and NiO x Nanoparticles were dispersed in an aprotic polar solvent and ball-milled to obtain NiO. x The dispersion is coated with the NiO on the passivation layer. x The dispersion was dried to obtain a hole transport layer.

8. The method according to claim 7, characterized in that, The NiO x The D50 of the nanoparticles is 5~60 nm.

9. The method according to claim 8, characterized in that, The NiO x The D50 of the nanoparticles is 10 nm.

10. The method according to claim 7, characterized in that, The aprotic polar solvent is selected from one or more of chlorobenzene, chloroform, toluene, diethyl ether, and ethyl acetate.

11. The method according to claim 10, characterized in that, The aprotic polar solvent is chlorobenzene.

12. The method according to claim 7, characterized in that, The ball milling time is 5-12 hours; and / or The ball-to-material ratio of the ball mill is (20~30):

1.

13. The method according to claim 12, characterized in that, The ball milling time is 6 hours; and / or The ball-to-material ratio of the ball mill is 25:

1.

14. The method according to claim 7, characterized in that, The NiO coating on the passivation layer x The dispersion step is carried out in an inert gas atmosphere.

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