A perovskite solar cell based on layered double hydroxide nanosheets and a preparation method thereof

Abstract

This invention discloses a perovskite solar cell based on layered double hydroxide nanosheets and its fabrication method, belonging to the field of solar cell technology. The perovskite solar cell comprises a charge transport layer, a perovskite light-absorbing layer, and a counter electrode stacked sequentially. A two-dimensional interface modification layer, composed of layered double hydroxide nanosheets, is disposed at at least one functional interface of the perovskite solar cell. The perovskite solar cell of this invention exhibits ultrathinness and uniformity, achieving efficient defect passivation and precise energy level control.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, specifically relating to a perovskite solar cell based on layered double hydroxide nanosheets and its preparation method. Background Technology

[0002] Perovskite solar cells have seen rapid development in recent years due to their advantages such as high light absorption coefficient, long carrier diffusion length, and simple fabrication process. However, the performance and stability of perovskite solar cells are heavily influenced by the quality of various internal interfaces. Nevertheless, perovskite solar cells still face challenges in terms of efficiency and stability: on the one hand, numerous defects exist at the interface between the perovskite light-absorbing layer and the charge transport layer, leading to severe nonradiative recombination, limiting the open-circuit voltage and fill factor, and consequently limiting the final photoelectric conversion efficiency; on the other hand, traditional organic hole transport materials (such as Spiro-OMeTAD) suffer from low mobility, poor stability, and hygroscopicity, severely impacting the long-term lifespan of the devices. Therefore, developing efficient interface modification layers to passivate these defects and suppress recombination is one of the core approaches to improving cell performance.

[0003] Layered double hydroxides (LDHs), also known as hydrotalcite, are a typical two-dimensional anionic clay material. Their structure consists of positively charged matrix layers and interlayer anions, exhibiting characteristics such as adjustable matrix elements, exchangeable interlayer anions, and large specific surface area, demonstrating potential in interface engineering.

[0004] Existing technologies, such as patent applications with publication numbers CN117580383A and WO2025139551A1, propose to composite layered bimetallic hydroxides with polymers, using the resulting composite material as a passivation layer. However, such composite material solutions have inherent limitations: First, the introduction of the polymer matrix may partially cover or shield the active sites on the surface of LDHs, weakening their direct and efficient interaction with perovskite defects; second, the formation of the composite material involves multiple chemical reactions (such as crosslinking), making the process relatively complex, and the uniformity and thickness of the final film are challenging to control precisely; more importantly, the insulation or energy level characteristics of the polymer components themselves may introduce unnecessary charge transport barriers or affect the precise matching of interface energy levels, making it impossible to optimally control carrier extraction while achieving efficient passivation.

[0005] Therefore, existing interface modification strategies based on LDHs-polymer composites have significant shortcomings in maximizing the intrinsic interface modification capabilities of LDHs while simultaneously achieving ultrathin, uniform interface structures with excellent defect passivation and precise energy level control. There is an urgent need for a new interface engineering approach that can directly utilize the two-dimensional properties of LDHs to construct more efficient and reliable interface modification layers. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the present invention aims to provide a perovskite solar cell based on layered double hydroxide nanosheets and its preparation method, so as to solve the technical problems that the existing perovskite solar cell structure is difficult to achieve ultra-thin, uniform and efficient defect passivation and precise energy level control capabilities, resulting in low interface layer defect passivation efficiency, energy level matching and interface quality.

[0007] This invention prepares positively charged layered double hydroxide (LDH) nanosheets via liquid-phase exfoliation, utilizing their two-dimensional properties to self-assemble into an ultrathin modification layer at the interface of a perovskite layer or charge transport layer. This layer not only effectively passivates interface defects but also modulates the interface energy level arrangement, promoting carrier extraction and transport.

[0008] To achieve the above objectives, the present invention employs the following technical solution: The present invention provides a perovskite solar cell based on layered double hydroxide nanosheets, comprising a charge transport layer, a perovskite light-absorbing layer and a counter electrode stacked sequentially, wherein a two-dimensional interface modification layer is disposed at at least one functional interface of the perovskite solar cell, the two-dimensional interface modification layer being composed of layered double hydroxide nanosheets.

[0009] Preferably, the at least one functional interface is the interface between the charge transport layer and the perovskite light-absorbing layer; the thickness of the two-dimensional interface modification layer is 1 nm to 100 nm.

[0010] Preferably, the charge transport layer includes an electron transport layer and a hole transport layer, the perovskite light-absorbing layer is located between the electron transport layer and the hole transport layer, and the at least one functional interface is selected from: the interface between the perovskite light-absorbing layer and the electron transport layer or the interface between the perovskite light-absorbing layer and the hole transport layer; the counter electrode is a back electrode.

[0011] Further preferably, the thickness of the two-dimensional interface modification layer is 5 nm to 30 nm. Increasing the thickness from 1 nm to 5 nm ensures more reliable formation of a continuous, pinhole-free, complete cover layer of LDH nanosheets on rough or porous substrate surfaces, avoiding the exposure of interface defects caused by excessively thin or missing local coverage. This allows the passivation groups (such as -OH) on its surface to fully contact and react with the defect sites at the perovskite interface, maximizing defect passivation efficiency. Simultaneously, a sufficiently thick LDH layer can more stably perform its energy level buffering function. Significantly reducing the upper limit of thickness from 100 nm to 30 nm aims to minimize the series resistance introduced by the interface modification layer itself. LDH is essentially an insulator or a wide bandgap semiconductor; excessive thickness severely hinders the tunneling or transport of charge (electrons or holes). Controlling the thickness to within 30 nm, especially for key charge carriers (such as holes) in most perovskite solar cells, allows them to effectively tunnel through the thin layer, thus achieving the interface modification function while almost without sacrificing charge extraction and transport efficiency.

[0012] Preferably, the chemical formula of the layered double hydroxide nanosheets is [M 2+ 1-x M 3+ x [(OH)2] x+ (A) n- ) x / n ·mH2O, where M 2+ Selected from Mg 2+ Ni 2+ Zn 2+ and Cu 2+ At least one of them, M 3+ Selected from Al 3+ Fe 3+ Co 3+ and Cr 3+ At least one of them, A n- It is an interlayer anion.

[0013] It should be noted that the general chemical formula [M] 2+ 1-x M 3+ x [(OH)2] x+ (A) n- ) x / n In mH2O, M 2+ It is a divalent metal cation, selected from Mg 2+ Ni 2+ Zn 2+ and Cu 2+ At least one of them; M 3+ It is a trivalent metal cation, selected from Al 3+ Fe3+ Co 3+ and Cr 3+ At least one of; A n- These are interlayer anions used to balance the positive charge on the layers, and are selected from NO3. - Cl - and CO3 2- At least one of them.

[0014] In the above general formula, the parameter x is M. 3+ The mole fraction of x determines the charge density of the layers. To obtain a stable layered crystal structure, the value of x ranges from 0.1 to 0.33.

[0015] Preferably, the value of x ranges from 0.2 to 0.33, within which the material exhibits both good structural stability and modifiability. The parameter n represents the interlayer anion A. n- The valence state (n=1, 2, 3, …) is determined by the selected anion itself.

[0016] Preferably, the M 2+ Mg 2+ or Zn 2+ The M 3+ For Al 3+ .

[0017] Preferably, the perovskite solar cell has a planar structure.

[0018] Preferably, the perovskite solar cell includes a conductive substrate, an electron transport layer, the perovskite light-absorbing layer, a hole transport layer, and a back electrode, which are stacked sequentially.

[0019] This invention also provides a method for preparing a perovskite solar cell based on layered double hydroxide nanosheets, comprising the following steps: S1: A substrate is provided, on which at least one functional interface to be modified is formed; S2: A dispersion for preparing layered double hydroxide nanosheets; S3: The dispersion is applied to at least one functional interface, and after treatment, the two-dimensional interface modification layer is formed to obtain a perovskite solar cell based on layered double hydroxide nanosheets. The functional interface refers to the interface between adjacent functional layers in the perovskite solar cell.

[0020] Preferably, in step S2, the dispersion of the layered double hydroxide nanosheets is prepared by a liquid phase exfoliation method, which includes: synthesizing a layered double hydroxide precursor; and exfoliating the layered double hydroxide precursor in an exfoliation solvent to obtain a colloidal solution containing the layered double hydroxide nanosheets.

[0021] Preferably, the stripping solvent includes at least one of formamide, N-methylpyrrolidone, and isopropanol.

[0022] Further preferably, in step S3, the dispersion is applied to the functional interface by spin coating, blade coating, spray coating, or dip coating. Spin coating generates uniform shear force through high-speed rotation, allowing the dispersion to spread and evaporate rapidly, easily forming nanoscale thicknesses with extremely high uniformity, making it particularly suitable for laboratory research and development and the fabrication of small-area precision devices. Blade coating and spray coating are both highly compatible with large-area, roll-to-roll production processes, facilitating the industrial scale-up of this technology. Blade coating allows for precise control of film thickness by adjusting the blade gap; spray coating can adapt to complex substrate surfaces, achieving non-contact uniform coverage. Dip coating controls film thickness by adjusting the pull-up speed and solution concentration, has low equipment requirements, and is suitable for various substrate shapes.

[0023] All of these methods are solution-based, enabling the direct and precise transport and deposition of LDH nanosheets with active sites onto the target interface between the charge transport layer and the perovskite layer, thereby constructing a modification layer in situ, effectively passivating interface defects and modulating energy levels.

[0024] More preferably, in step S3, the treatment includes drying and / or annealing. This step ensures the stability of the interface modification layer structure and good contact with adjacent layers, and its main function is reflected in: The main purpose of drying is to thoroughly remove the stripping solvent and dispersion medium, preventing residual solvent from adversely affecting subsequent processes or device operation. Simultaneously, it allows LDH nanosheets to tightly pack and fix on the substrate surface, forming a stable solid modification layer. An appropriate annealing temperature (150℃) provides activation energy for the passivation reaction between the hydroxyl groups (-OH) on the LDH surface and the uncoordinated ions at the perovskite interface, resulting in a more complete and robust passivation effect. Compared with existing technologies, this invention has the following beneficial effects: This invention provides a perovskite solar cell based on layered double hydroxide (LDH) nanosheets. The core of this invention lies in introducing a two-dimensional interface modification layer composed of LDH nanosheets, achieving the following effects: First, as a two-dimensional material, the LDH nanosheets can form an ultrathin, dense, and uniform capping layer at the interface, effectively reducing pinholes and poor contact at the interface, resulting in an ultrathin and uniform perovskite solar cell. Second, the surface of the LDH nanosheets is rich in functional groups such as hydroxyl (-OH), which can interact with uncoordinated lead ions (Pb) on the surface of the perovskite layer. 2+ The perovskite solar cell achieves efficient defect passivation by coordinating with defect sites such as halogen vacancies or other halogen vacancies, thereby passivating interface defects, suppressing nonradiative recombination, and increasing open-circuit voltage. Thirdly, precise energy level control: the band structure of the LDH (valence band top and conduction band bottom positions) can be controlled by its metal ion composition (M...). 2+ M 3+ The energy levels of LDHs are regulated by adjusting the interlayer anions. Placed at the functional interface, they act as an energy level buffer layer, improving energy level alignment between adjacent functional layers (such as the transport layer and the perovskite layer), promoting charge extraction, and reducing energy loss at the interface, thereby achieving precise energy level control of perovskite solar cells. Furthermore, the hydrophobic and chemically stable LDH nanosheets can act as a barrier layer to prevent water and oxygen erosion, while also inhibiting the diffusion of ions from the metal electrode or transport layer into the perovskite layer, greatly improving the environmental and thermal stability of the cell.

[0025] Furthermore, the specific location of the two-dimensional interface modification layer is defined, ensuring that the two-dimensional interface modification layer is applied to the core interface of carrier generation and separation, directly optimizing the high concentration of defects and severe recombination losses at this location, so that the technical effect is exerted in the most critical part.

[0026] Furthermore, the thickness of the two-dimensional interface modification layer is limited to 1 nm–100 nm. The lower limit (1 nm) ensures the formation of a continuous and effective capping layer, sufficient to achieve defect passivation and energy level modulation. The upper limit (100 nm) avoids the introduction of excessive series resistance by an overly thick insulating layer, which would hinder charge transport. This range achieves the optimal balance between ensuring functionality and maintaining charge transport efficiency.

[0027] Furthermore, by selecting different M 2+ and M 3+ By combining these elements, the Fermi level and band structure of LDH can be systematically controlled, thus providing a wide range of material choices for achieving energy level matching with different perovskite compositions or transport materials.

[0028] The following further explains the modulation mechanism of the Fermi level and band structure of LDH: The band structure of LDH (primarily the positions of its valence band top (VBM) and conduction band bottom (CBM) can be precisely controlled through its unique crystal structure and chemical composition. This is the core principle behind its ability to function as a highly efficient interfacial buffer layer. The specific control methods are mainly based on the following three levels: 1. Regulation of the composition of metal ion plates (main regulation method) The band structure of the LDH is mainly determined by the metal hydroxide octahedral units on its layers.

[0029] M 2+ Choice of ion: The type of divalent metal ion directly affects the energy level of the conduction band bottom (CBM). For example, using Mg, which has lower electronegativity... 2+ The LDH constructed typically has a deeper CBM (lower energy level); while using d 10 electronic configuration of Zn 2+ When this occurs, its d orbitals will participate in bonding, which may narrow the band gap and affect the energy level position.

[0030] M 3+ Choice and M 2+ / M 3+ Ratio (x value): The introduction and ratio of trivalent metal ions will significantly change the charge density and electronic structure of the laminate.

[0031] Species influence: For example, the introduction of Fe 3+ (with 3D) 5 LDHs (electron-dependent hydroxyl groups) typically exhibit narrower band gaps and different energy level positions due to the contribution of Fe 3d orbitals, and may even possess semiconductor properties.

[0032] The influence of the proportion (x value): M 3+ Increasing the content (x value) increases the positive charge density of the laminations, leading to more anions being inserted to balance the charge. This also alters the metal-oxygen-metal (MOM) bonding environment and electronic state density within the laminations, thus systematically regulating the energies of the valence band top (VBM) and conduction band bottom (CBM). By adjusting the x value, the band structure of the LDH can be continuously or stepwise fine-tuned.

[0033] 2. Interlayer anions (A) n- Regulation (auxiliary and fine-tuning methods) Interlayer anions bind to positively charged layers through electrostatic interactions.

[0034] Electronic effects: Anions can influence the electron cloud distribution of hydroxyl groups (-OH) on the laminations through hydrogen bonding or electrostatic interactions, thereby slightly modulating the energy of VBM (mainly derived from the hybridization of O 2p and M 3d orbitals).

[0035] Spatial and inductive effects: The size, polarity, and distribution of anions affect the interlayer spacing and local electric field, which in turn indirectly affect charge transport and energy level alignment.

[0036] 3. Regulation of nanosheet thickness (quantum confinement effect) When bulk LDH is peeled into single-layer or few-layer nanosheets, a quantum confinement effect is generated.

[0037] Principle: Reducing the thickness of nanosheets usually leads to an increase in their band gap, and the positions of VBM and CBM will shift, allowing for further fine-tuning of the band gap by controlling the degree of exfoliation (number of nanosheet layers).

[0038] In summary, the modulation of the LDH band structure is a multi-parameter coordinated process: by selecting M... 2+ and M 3+ The types and proportions of these materials can be used to achieve coarse adjustment and directional design of the band structure; by selecting interlayer anions and controlling the thickness of the nanosheets, the band structure can be finely optimized so that its energy level can be matched with a specific perovskite light-absorbing layer or charge transport material.

[0039] Furthermore, M was specified. 2+ and M 3+ The obtained MgAl-LDH and ZnAl-LDH layered double hydroxide nanosheets have suitable band positions, are easy to form good energy level matching with common perovskite materials, and have good chemical stability.

[0040] Furthermore, limiting the perovskite solar cell to a formal planar structure demonstrates excellent synergy with the layered double hydroxide nanosheet two-dimensional interface modification layer of this invention, maximizing the effect of interface modification and achieving the highest photoelectric conversion efficiency currently available (e.g., 22.5% in Example 1). Simultaneously, this structure boasts mature technology and good compatibility, facilitating the stable and reproducible fabrication of high-performance cells.

[0041] This invention also provides a method for preparing a perovskite solar cell based on layered double hydroxide nanosheets. The dispersion of the layered double hydroxide nanosheets is prepared by liquid phase exfoliation. Liquid phase exfoliation can effectively peel the bulk LDH into few-layer or single-layer nanosheets, maximizing the exposure of its active surface and edge sites, thereby enhancing its defect passivation ability. Simultaneously, the obtained colloidal solution has good stability, facilitating subsequent uniform film formation.

[0042] Furthermore, the exfoliation solvent was specified as formamide, N-methylpyrrolidone (NMP), or isopropanol. These solvents have suitable polarity and surface tension, which can effectively intercalate into the LDH interlayer, weaken the interlayer forces, thereby achieving efficient and high-quality exfoliation and obtaining a high-concentration, low-defect LDH nanosheet dispersion. Attached Figure Description

[0043] Figure 1 This is a structural diagram of the perovskite solar cell of the present invention. Detailed Implementation

[0044] To enable those skilled in the art to understand the features and effects of the present invention, the following descriptions and definitions are only general descriptions of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in the event of any conflict, the definitions in this specification shall prevail.

[0045] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0046] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0047] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0048] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0049] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0050] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" represents weight percentage, "parts" represents parts by weight, and "ratio" represents weight proportion.

[0051] Example 1 This embodiment provides a method for fabricating a perovskite solar cell based on layered double hydroxide nanosheets, as detailed below: S1: Providing a substrate and functional interface: Providing FTO conductive glass and preparing a dense TiO2 layer on the FTO conductive glass to form a substrate with the TiO2 layer surface as the functional interface to be modified; S2: Preparation of nanosheet dispersion: A ZnAl-NO3 layered double hydroxide precursor was synthesized by co-precipitation. The precursor was dispersed in the exfoliating solvent formamide, and liquid-phase exfoliation was carried out by stirring under a nitrogen atmosphere. After centrifugation, a colloidal dispersion of layered double hydroxide nanosheets was obtained. S3: Forming a two-dimensional interface modification layer of layered double hydroxide nanosheets by applying a colloidal dispersion: The above colloidal dispersion was spin-coated at 2000 rpm onto the surface of the TiO2 layer of the substrate obtained in S1 (i.e., the interface between the electron transport layer and the subsequent perovskite light-absorbing layer), and then annealed at 150°C for 10 minutes to form a two-dimensional interface modification layer of layered double hydroxide nanosheets with a thickness of approximately 10 nm. Subsequently, Cs was sequentially deposited on the two-dimensional interface modification layer of layered double hydroxide nanosheets. 0.05 FA 0.79 MA 0.16 PbI 2.48 Br 0.52 Perovskite light-absorbing layer; S4: Preparation of the second layer of layered double hydroxide nanosheet two-dimensional interface modification layer: The above colloidal dispersion was spin-coated again on the surface of the perovskite light-absorbing layer (i.e. the interface between the perovskite light-absorbing layer and the subsequent hole transport layer) at a speed of 2000 rpm, and then annealed at 150°C for 10 minutes to form a second layer of layered double hydroxide nanosheet two-dimensional interface modification layer with a thickness of about 10 nm. S5: Deposition of hole transport layer and back electrode: A Spiro-OMeTAD hole transport layer is sequentially deposited on the second two-dimensional interface modification layer, and finally an Ag back electrode is deposited by evaporation, resulting in the following... Figure 1The perovskite solar cell shown has a formal planar structure consisting of a transparent conductive substrate (FTO conductive glass), an electron transport layer (TiO2 dense layer), a layered double hydroxide nanosheet two-dimensional interface modification layer, a perovskite light-absorbing layer, a hole transport layer, and a back electrode (Ag counter electrode).

[0052] Performance results: The perovskite solar cell prepared in this embodiment has a photoelectric conversion efficiency of 22.5% as tested.

[0053] Example 2 The difference between this embodiment and Embodiment 1 is that, in step S3, no layered double hydroxide nanosheet dispersion is applied, that is, no two-dimensional interface modification layer is formed, and a perovskite light-absorbing layer is directly deposited on the FTO / TiO2 substrate. The subsequent steps are exactly the same as in Embodiment 1.

[0054] Performance results: The photoelectric conversion efficiency of the obtained perovskite solar cell was tested to be 20.1%.

[0055] Comparative Example 1 Referring to existing technology (CN117580383A), perovskite solar cells are prepared using polydopamine crosslinked modified layered bimetallic hydroxides as passivation layers, but the preparation process is relatively complex.

[0056] Performance results: The efficiency of the obtained perovskite solar cell was 21.3% as tested, but the fill factor was slightly lower than that of Example 1.

[0057] Example 3 The preparation method in this embodiment is the same as that in Example 1, except that: In step S3, the nanosheet dispersion obtained in S2 is diluted, and a two-dimensional interface modification layer with an average thickness of about 1 nm-2 nm is formed on the surface of the TiO2 layer by optimizing the spin coating process.

[0058] The remaining steps, including S1 providing the substrate and interface, S2 preparing the dispersion, and subsequent deposition of each functional layer, are the same as in Example 1.

[0059] Performance results: The photoelectric conversion efficiency of the obtained perovskite solar cell was tested to be 21.8%.

[0060] Example 4 The preparation method in this embodiment is the same as that in Example 1, except that: In step S3, the nanosheet dispersion obtained in S2 is spin-coated multiple times to construct a two-dimensional interface modification layer with an average thickness of about 90 nm-100 nm on the surface of the TiO2 layer.

[0061] The remaining steps are the same as in Example 1.

[0062] Performance results: The photoelectric conversion efficiency of the obtained perovskite solar cell was tested to be 21.0%.

[0063] Example 5 The preparation method in this embodiment is the same as that in Example 1, except that: In step S2, the prepared layered double hydroxide precursor is MgAl-NO3-LDHs (i.e., M... 2+ Mg 2+ M 3+ For Al 3+ ), and the corresponding nanosheet dispersion was obtained by peeling.

[0064] In step S3, the thickness of the formed two-dimensional interface modification layer is approximately 10 nm.

[0065] The remaining steps are the same as in Example 1.

[0066] Performance results: The photoelectric conversion efficiency of the obtained perovskite solar cell was tested to be 22.1%.

[0067] Example 6 The preparation method in this embodiment is the same as that in Example 1, except that: In step S2, the prepared layered double hydroxide precursor is ZnFe-Cl-LDHs (i.e., M). 2+ Zn 2+ M 3+ For Fe 3+ Interlayer anion A n- For Cl - ), and the corresponding nanosheet dispersion was obtained by peeling.

[0068] In step S3, the thickness of the formed two-dimensional interface modification layer is approximately 10 nm.

[0069] The remaining steps are the same as in Example 1.

[0070] Performance results: The photoelectric conversion efficiency of the obtained perovskite solar cell was tested to be 21.9%.

[0071] Example 7 The preparation method in this embodiment is the same as that in Example 1, except that: In step S2, the prepared layered double hydroxide precursor is ZnAl-NO3-LDHs (i.e., M). 2+ Zn 2+ M 3+ For Al 3+ Interlayer anion A n- CO32- The specific synthesis method is as follows: A co-precipitation method is used, where a mixed salt solution of zinc nitrate and aluminum nitrate is co-precipitated with a sodium carbonate solution at a constant pH and temperature. After aging, washing, and drying, a ZnAl-NO3-LDHs precursor is obtained. This precursor is dispersed in the exfoliating solvent formamide, and liquid-phase exfoliation is performed under a nitrogen atmosphere with stirring. After centrifugation, the corresponding LDHs nanosheet colloidal dispersion is obtained.

[0072] In step S3, the thickness of the formed two-dimensional interface modification layer is approximately 10 nm.

[0073] The remaining steps, including providing the substrate in S1, forming the modification layer in S3, and subsequently depositing the functional layers, are the same as in Example 1, ultimately resulting in a perovskite solar cell with a formal planar structure.

[0074] Performance results: The photoelectric conversion efficiency of the obtained perovskite solar cell was 21.7% as tested.

[0075] Example 8 The preparation method in this embodiment is the same as that in Example 1, except that: In step S2, the layered double hydroxide precursor is dispersed in N-methylpyrrolidone (NMP), liquid phase exfoliation is performed under a nitrogen atmosphere, and after centrifugation, a colloidal dispersion of LDH nanosheets is obtained.

[0076] The resulting two-dimensional interface modification layer is approximately 10 nm thick, and the battery structure is also a formal planar structure.

[0077] The remaining steps are exactly the same as in Example 1.

[0078] Performance results: The photoelectric conversion efficiency of the obtained perovskite solar cell was tested to be 22.0%.

[0079] Example 9 The preparation method in this embodiment is the same as that in Example 1, except that: In step S2, the layered double hydroxide precursor is dispersed in isopropanol (IPA), liquid phase exfoliation is performed under a nitrogen atmosphere, and after centrifugation, a colloidal dispersion of LDH nanosheets is obtained.

[0080] The resulting two-dimensional interface modification layer is approximately 10 nm thick, and the battery structure is also a formal planar structure.

[0081] The remaining steps are exactly the same as in Example 1.

[0082] Performance results: The photoelectric conversion efficiency of the obtained perovskite solar cell was tested to be 21.5%.

[0083] Industrial applicability: The perovskite solar cell fabrication process provided by this invention is simple, easy to achieve large-area fabrication, and has significant advantages in improving efficiency and stability.

[0084] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A perovskite solar cell based on layered double hydroxide nanosheets, characterized in that, The perovskite solar cell comprises a charge transport layer, a perovskite light-absorbing layer, and a counter electrode stacked sequentially. A two-dimensional interface modification layer is disposed at at least one functional interface of the perovskite solar cell, and the two-dimensional interface modification layer is composed of layered double hydroxide nanosheets.

2. The perovskite solar cell based on layered double hydroxide nanosheets according to claim 1, characterized in that, The at least one functional interface is the interface between the charge transport layer and the perovskite light-absorbing layer; the thickness of the two-dimensional interface modification layer is 1 nm to 100 nm.

3. A perovskite solar cell based on layered double hydroxide nanosheets according to claim 1 or 2, characterized in that, The charge transport layer includes an electron transport layer and a hole transport layer, the perovskite light-absorbing layer is located between the electron transport layer and the hole transport layer, and the at least one functional interface is selected from: the interface between the perovskite light-absorbing layer and the electron transport layer or the interface between the perovskite light-absorbing layer and the hole transport layer; the counter electrode is a back electrode.

4. A perovskite solar cell based on layered double hydroxide nanosheets according to claim 1, characterized in that, The chemical formula of the layered double hydroxide nanosheets is [M 2+ 1-x M 3+ x [(OH)2] x+ (A) n- ) x / n ·mH2O, where M 2+ Selected from Mg 2+ Ni 2+ Zn 2+ and Cu 2+ At least one of them, M 3+ Selected from Al 3+ Fe 3+ Co 3+ and Cr 3+ At least one of them, A n- It is an interlayer anion.

5. A perovskite solar cell based on layered double hydroxide nanosheets according to claim 4, characterized in that, The M 2+ Mg 2+ or Zn 2+ The M 3+ For Al 3+ .

6. A perovskite solar cell based on layered double hydroxide nanosheets according to claim 1, characterized in that, The perovskite solar cell has a formal planar structure.

7. A perovskite solar cell based on layered double hydroxide nanosheets according to claim 3, characterized in that, The perovskite solar cell comprises a conductive substrate, an electron transport layer, the perovskite light-absorbing layer, a hole transport layer, and a back electrode, which are stacked sequentially.

8. A method for preparing a perovskite solar cell based on layered double hydroxide nanosheets according to any one of claims 1-7, characterized in that, Includes the following steps: S1: A substrate is provided, on which at least one functional interface to be modified is formed; S2: A dispersion for preparing layered double hydroxide nanosheets; S3: The dispersion is applied to at least one functional interface, and after treatment, the two-dimensional interface modification layer is formed to obtain a perovskite solar cell based on layered double hydroxide nanosheets. The functional interface refers to the interface between adjacent functional layers in the perovskite solar cell.

9. The preparation method according to claim 8, characterized in that, In step S2, the dispersion of the layered double hydroxide nanosheets is prepared by a liquid phase exfoliation method, which includes: synthesizing a layered double hydroxide precursor; and exfoliating the layered double hydroxide precursor in an exfoliation solvent to obtain a colloidal solution containing the layered double hydroxide nanosheets.

10. The preparation method according to claim 9, characterized in that, The stripping solvent includes at least one of formamide, N-methylpyrrolidone, and isopropanol.

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