A two-dimensional perovskite vertically oriented growth solar cell and a preparation method thereof

Abstract

The application belongs to the technical field of perovskite solar cells, and particularly relates to a two-dimensional perovskite vertically-grown solar cell and a preparation method thereof. The solar cell comprises, from bottom to top, a substrate layer, an electron transport layer, a perovskite absorption layer, a hole transport layer and a metal top electrode layer. The electron transport layer comprises a tin dioxide film and tin dioxide nanoparticles, and the tin dioxide nanoparticles are arranged on the side of the perovskite absorption layer of the tin dioxide film. The perovskite absorption layer comprises a two-dimensional perovskite material layer and a three-dimensional perovskite material layer, the two-dimensional perovskite material layer is in contact with the tin dioxide nanoparticles, and the three-dimensional perovskite material layer is in contact with the hole transport layer. The rough surface of the tin dioxide nanoparticles, the two-dimensional perovskite material layer and the three-dimensional perovskite material layer realize vertically-oriented crystal growth, reduce the existence of grain boundaries, improve the diffusion length and migration efficiency of carriers, and thus improve the photoelectric conversion efficiency.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell technology, specifically relating to a two-dimensional perovskite vertically oriented solar cell and its preparation method. Background Technology

[0002] In recent years, perovskite solar cells have become a hot topic in photovoltaic technology research due to their high photoelectric conversion efficiency, low-cost fabrication process, and enormous potential in the photovoltaic field. As a representative of the next generation of photovoltaic technology, perovskite solar cells have achieved certified photoelectric conversion efficiencies exceeding 26% in laboratory single-junction cells thanks to their excellent light absorption performance, low defect density, and superior carrier transport capabilities. However, the stability of perovskite materials remains a major bottleneck for their further promotion and application, especially when exposed to moisture, light, and heat conditions for extended periods, where the performance of perovskite solar cells is prone to degradation. Therefore, balancing the efficiency and stability of perovskite solar cells is a significant challenge in current research.

[0003] Among perovskite materials, three-dimensional perovskite materials (such as MAPbI3 and FAPbI3) are currently the most widely used absorber layer materials in perovskite solar cells. Three-dimensional perovskite materials possess high light absorption efficiency, good carrier mobility, and long carrier diffusion length, which contribute to their excellent performance in high-efficiency photovoltaic devices. However, three-dimensional perovskite materials are highly sensitive to the environment; their crystal structure is prone to decomposition under humidity and heat, leading to poor device stability. Furthermore, defect recombination easily occurs at the interface, further limiting the improvement of their photoelectric conversion efficiency.

[0004] In contrast, two-dimensional perovskite materials (such as (PEA)₂PbI₄) exhibit significant advantages due to their layered structure. The organic cation layer in two-dimensional perovskites possesses hydrophobicity and steric hindrance effects, effectively blocking the intrusion of moisture and oxygen, thereby significantly improving the device's resistance to moisture and oxidation. Furthermore, the low defect density of two-dimensional perovskite materials effectively reduces interfacial nonradiative recombination losses, and their smooth surface also helps optimize interfacial charge transport efficiency. However, two-dimensional perovskite materials have relatively low carrier transport capacity, mainly because the organic cation layer in their layered structure forms a barrier to the vertical migration of electrons and holes. Simultaneously, their wide band gap (typically greater than 2 eV) results in a narrow absorption range of the solar spectrum, especially weak absorption of visible and near-infrared light, which severely limits their photoelectric conversion efficiency.

[0005] To combine the advantages of two-dimensional (2D) and three-dimensional (3D) perovskite materials, 2D / 3D composite perovskite absorber layers have become a research hotspot in recent years. The 2D / 3D composite structure, by coating the electron transport layer with a layer of 2D perovskite material, provides interface passivation and protection, significantly reducing interface defect density while enhancing the device's moisture resistance and heat resistance. Based on this, depositing a 3D perovskite material layer as the main absorber layer effectively compensates for the insufficient light absorption capacity of 2D perovskite. The 2D / 3D composite structure not only utilizes the stability advantage of 2D perovskite but also optimizes carrier transport paths by constructing gradient energy level structures, significantly improving photoelectric performance. Simultaneously, the 2D perovskite layer can serve as a template to promote the vertical orientation growth of 3D perovskite crystals, further improving carrier transport efficiency. However, the inconsistency in crystal orientation between the 2D and 3D perovskite material layers hinders carrier transport, preventing the full utilization of the advantages of 2D / 3D composite perovskite solar cells. Summary of the Invention

[0006] To address the above problems, this invention provides a two-dimensional perovskite vertically oriented solar cell, comprising, from bottom to top, a substrate layer, an electron transport layer, a perovskite absorber layer, a hole transport layer, and a metal top electrode layer. The electron transport layer comprises a tin dioxide thin film and tin dioxide nanoparticles, with the tin dioxide nanoparticles positioned on the perovskite absorber layer side of the tin dioxide thin film. The perovskite absorber layer comprises a two-dimensional perovskite material layer and a three-dimensional perovskite material layer, with the two-dimensional perovskite material layer in contact with the tin dioxide nanoparticles and the three-dimensional perovskite material layer in contact with the hole transport layer.

[0007] This invention achieves vertically oriented crystal growth through the rough surface of tin dioxide nanoparticles, two-dimensional perovskite material layers, and three-dimensional perovskite material layers. This vertically oriented structure reduces the presence of grain boundaries, increases the diffusion length and migration efficiency of charge carriers, thereby improving photoelectric conversion efficiency.

[0008] Furthermore, the thickness of the tin dioxide film is 30-50 nanometers, and the particle size of the tin dioxide nanoparticles is 5-20 nanometers.

[0009] Furthermore, tin dioxide nanoparticles are partially embedded in a tin dioxide thin film. This partially embedded structure enhances the bonding force between the nanoparticles and the film. This robust bonding significantly improves the long-term stability of the electron transport layer and enhances the durability of the perovskite solar cell. Additionally, this embedded design shortens the electron transport path between the tin dioxide nanoparticles and the tin dioxide thin film, reducing resistance losses at the interface and thus improving the efficiency of electron transport from the nanoparticles to the film. Moreover, the surface of the partially embedded tin dioxide nanoparticles remains exposed beneath the perovskite material layer; their raised particle structure enhances light scattering and light-trapping effects, thereby increasing the light utilization rate of the perovskite absorption layer and further improving the photoelectric conversion efficiency.

[0010] Furthermore, the substrate layer is made of ITO or FTO, the hole transport layer is made of Spiro-OMeTAD, and the metal top electrode layer is made of gold.

[0011] Furthermore, zinc oxide nanoparticles are doped into tin dioxide nanoparticles. The doped zinc oxide (ZnO) nanoparticles can effectively guide the preferential growth of two-dimensional perovskite crystals along the vertical direction by optimizing surface roughness, providing high-energy nucleation sites, and improving interfacial lattice matching.

[0012] On the other hand, the present invention provides a method for fabricating a two-dimensional perovskite vertically oriented solar cell, comprising the following steps:

[0013] Step 1: Prepare a tin dioxide thin film on the substrate layer;

[0014] Step 2: Set tin dioxide nanoparticles on a tin dioxide thin film;

[0015] Step 3: Prepare a two-dimensional perovskite material layer on tin dioxide nanoparticles;

[0016] Step 4: Prepare a three-dimensional perovskite material layer on the two-dimensional perovskite material layer;

[0017] Step 5: Prepare a hole transport layer on the three-dimensional perovskite material layer;

[0018] Step 6: Fabricate a metal top electrode layer on the hole transport layer.

[0019] Furthermore, in step 1, a tin dioxide thin film is prepared on ITO using a spin coating method.

[0020] Furthermore, in step 2, tin dioxide nanoparticles are spin-coated onto a tin dioxide film using a spin coating method.

[0021] Furthermore, in step 3, a precursor solution of two-dimensional perovskite material is spin-coated onto the surface of tin dioxide nanoparticles, and after annealing, a two-dimensional perovskite material layer is obtained.

[0022] Furthermore, in step 4, a precursor solution of the three-dimensional perovskite material is spun onto the surface of the two-dimensional perovskite material layer, and after annealing, a three-dimensional perovskite material layer is obtained.

[0023] The beneficial effects of this invention are:

[0024] This invention promotes the vertically oriented growth of two-dimensional and three-dimensional perovskites through the rough surface of tin dioxide nanoparticles, thereby forming a highly ordered crystal structure. This vertically oriented perovskite crystal significantly reduces the number of grain boundaries, lowers carrier scattering and recombination losses between grains, and improves carrier diffusion length and migration efficiency. Furthermore, the partially embedded tin dioxide nanoparticle protrusions enhance light scattering and light-trapping effects, improving the light utilization rate of the perovskite absorption layer and thus effectively enhancing photoelectric conversion efficiency.

[0025] This invention enhances the bonding force between tin dioxide nanoparticles and a tin dioxide thin film by designing a structure in which tin dioxide nanoparticles are partially embedded. This strong bonding effectively prevents the nanoparticles from detaching during long-term use due to mechanical stress or environmental factors (such as thermal stress), thereby significantly improving the mechanical stability and durability of the electron transport layer. Furthermore, the two-dimensional perovskite layer possesses excellent moisture resistance and oxidation resistance, which, when combined with the three-dimensional perovskite, further enhances the overall environmental stability of the device, enabling it to maintain high photoelectric performance even in complex environments such as humidity and high temperatures.

[0026] This invention employs a spin-coating method to prepare electron transport layers, two-dimensional perovskite layers, and three-dimensional perovskite layers. The process is simple, low-cost, and easy to control. The spin-coating process is not only suitable for laboratory research but also has good process compatibility, making it suitable for large-scale industrial production. Furthermore, the combination of tin dioxide thin films and embedded tin dioxide nanoparticles requires no complex processing steps, further reducing production difficulty and laying the foundation for the commercial application of high-efficiency perovskite solar cells.

[0027] Based on the above beneficial effects, this invention has good application prospects in the field of perovskite solar cell technology. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a two-dimensional perovskite solar cell grown in a vertical orientation.

[0029] In the diagram: 1. Substrate layer; 2. Electron transport layer; 3. Perovskite absorber layer; 4. Hole transport layer; 5. Metal top electrode layer. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided with reference to the accompanying drawings and embodiments.

[0031] Example 1

[0032] This invention provides a two-dimensional perovskite vertically oriented solar cell, such as... Figure 1 As shown, it includes a base layer 1, an electron transport layer 2, a perovskite absorber layer 3, a hole transport layer 4, and a metal top electrode layer 5.

[0033] The substrate layer 1 is made of ITO or FTO transparent conductive glass (approximately 1.1 mm thick), which has good conductivity and allows light to enter the perovskite absorber layer, providing mechanical support and functioning as the bottom electrode for the photovoltaic device. The electron transport layer 2 consists of a tin dioxide film and tin dioxide nanoparticles partially embedded in the film. The tin dioxide film is 30-50 nm thick, providing a continuous and uniform electron transport path. The tin dioxide nanoparticles have a particle size of 5-20 nm and are partially embedded in the film to enhance the bonding force between the particles and the film. The exposed particle structure increases the surface roughness of the electron transport layer, providing a template for the vertical orientation growth of the perovskite crystals. The perovskite absorber layer 3 includes a two-dimensional perovskite material layer and a three-dimensional perovskite material layer. The two-dimensional perovskite material layer is (PEA)₂PbI₄; the three-dimensional perovskite material layer is MAPbI₃. The two-dimensional perovskite material layer directly contacts the tin dioxide nanoparticles. Its vertically oriented crystal structure enhances carrier diffusion length and migration efficiency. A three-dimensional perovskite material layer sits atop the two-dimensional layer, contacting the hole transport layer and providing efficient light absorption and charge separation for the solar cell. Hole transport layer 4, made of Spiro-OMeTAD material (approximately 50-100 nm thick), selectively transports photogenerated holes and blocks electrons from reinjecting into the perovskite layer, thus reducing recombination losses. The top layer, a metal top electrode layer 5 made of gold (Au) with a thickness of 50-100 nm, collects holes and conducts current. This overall structure, through the organic integration of these functional layers, not only improves photoelectric conversion efficiency but also significantly enhances the device's long-term stability and environmental tolerance.

[0034] In this invention, the vertically oriented structure of the two-dimensional perovskite enables the inorganic [PbI6] to... 4-The octahedrons are arranged in an ordered manner along the vertical direction (c-axis), forming a continuous carrier transport channel that runs through the entire perovskite film. This ordered stacking of inorganic layers significantly reduces the number of grain boundaries, which are often the main sites of scattering and recombination during carrier transport. By reducing grain boundaries, the probability of carrier scattering and recombination in the vertical direction is greatly reduced, thereby improving transport efficiency and diffusion length. Secondly, the inorganic layers of two-dimensional perovskites are the main channels for carrier transport, while organic cation layers (such as phenylethylamine cations PEA⁺) hinder lateral carrier transport due to their low conductivity. In randomly oriented two-dimensional perovskites, carriers have to overcome the obstacles of the interlayer organic layers, leading to a decrease in transport efficiency. The vertically oriented structure avoids this problem; the arrangement direction of the inorganic layers is consistent with the carrier migration path, thus providing a low-resistance transport channel and significantly optimizing carrier migration efficiency. At the same time, vertically oriented growth also reduces the interlayer impedance in two-dimensional perovskite layers. Through the ordered arrangement in the vertical direction, the interlayer spacing inside the crystal is more uniform and compact, thereby reducing interlayer resistance. Meanwhile, the vertically oriented structure improves the interfacial bonding quality between the perovskite layer and the tin dioxide electron transport layer, as well as the 3D perovskite layer. This optimized interface lowers the potential barriers for charge injection and extraction, further improving the efficiency of carrier transport from the 2D perovskite layer to other functional layers. More importantly, the vertically oriented 2D perovskite layer provides an ordered template for the subsequent growth of the 3D perovskite material layer. Guided by the 2D perovskite material layer, the 3D perovskite material layer also achieves vertically ordered growth, resulting in a continuous crystal orientation throughout the perovskite absorber layer 3. This structure not only enhances the coupling efficiency between the 2D and 3D perovskite layers but also optimizes the carrier migration path within the entire absorber layer, thereby further improving the photoelectric conversion efficiency of the solar cell.

[0035] Example 2

[0036] This invention provides a method for fabricating a two-dimensional perovskite vertically oriented solar cell, comprising the following steps:

[0037] Step 1: Prepare a tin dioxide thin film on substrate layer 1. Specifically, an ITO glass with dimensions of 25 mm × 25 mm is selected as the substrate. The substrate is first ultrasonically cleaned with acetone, isopropanol, and deionized water for 10 minutes each, and then treated with a plasma cleaner for 5 minutes to remove surface contaminants and enhance hydrophilicity. Then, a 0.1 M tin dioxide (SnO2) precursor solution is prepared by dissolving SnCl4·5H2O in isopropanol and stirring thoroughly. The solution is then spin-coated onto the ITO glass surface (3000 rpm, 30 seconds), followed by annealing at 150 °C for 30 minutes to form a uniform tin dioxide thin film with a thickness of 30-50 nanometers.

[0038] Step 2: Deposition of tin dioxide nanoparticles on a tin dioxide film. Specifically, a solution of tin dioxide nanoparticles with a particle size of 10 nm was prepared. The tin dioxide nanoparticles were dispersed in isopropanol solvent (concentration 5 wt%) and ultrasonically stirred for 30 minutes to ensure uniform dispersion. Subsequently, the nanoparticle solution was spin-coated onto the annealed tin dioxide film using a spin-coating method (3000 rpm, 30 seconds) to form an embedded structure, in which some nanoparticles are embedded in the film surface. Finally, the sample was annealed at 150 °C for 15 minutes to stabilize the distribution of nanoparticles and enhance their adhesion to the film.

[0039] Step 3: Preparation of a two-dimensional perovskite material layer on tin dioxide nanoparticles. Specifically, a precursor solution of phenylethylamine iodide (PEAI) and lead iodide (PbI2) mixed in a 2:1 molar ratio was prepared and dissolved in a DMF:DMSO mixed solvent with a volume ratio of 4:1, resulting in a solution concentration of 0.5 M. The solution was stirred at 60 °C for 2 hours until completely dissolved. This precursor solution was drop-coated onto the surface of tin dioxide nanoparticles and uniformly formed by spin coating (2000 rpm, 30 seconds). After annealing at 100 °C for 10 minutes, a (PEA)2PbI4 two-dimensional perovskite material layer with a thickness of 10-20 nm was finally formed. Its vertically oriented crystal structure significantly optimized the carrier transport path.

[0040] Step 4: Prepare a three-dimensional perovskite material layer on the two-dimensional perovskite material layer. Specifically, methylamine iodide (MAI) and lead iodide (PbI2) are mixed in a 1:1 molar ratio and dissolved in a 4:1 DMF:DMSO mixed solvent to prepare a 1.2 M three-dimensional perovskite precursor solution. The solution is stirred at 60 °C for 1 hour to ensure complete dissolution. The precursor solution is drop-coated onto the surface of the two-dimensional perovskite material layer, and a thin film is deposited by spin coating (4000 rpm, 30 seconds). An anti-solvent (such as toluene) is added simultaneously to promote crystal nucleation and growth. The sample is then annealed at 120 °C for 15 minutes, ultimately forming a MAPbI3 three-dimensional perovskite material layer with a thickness of 400-700 nm. The crystal growth is vertically ordered and forms a good bond with the two-dimensional layer.

[0041] Step 5: Prepare hole transport layer 4 on the three-dimensional perovskite material layer. Specifically, to prepare hole transport layer 4, first prepare a Spiro-OMeTAD solution by dissolving 72.3 mg of Spiro-OMeTAD in 1 ml of chlorobenzene solvent, and add 17.5 µl of Li-TFSI solution (520 mg of Li-TFSI dissolved in 1 ml of acetonitrile) and 28.8 µl of tri-tert-butyl phosphate (TBP) as additives, and stir thoroughly. Then, drop-coat the solution onto the surface of the three-dimensional perovskite material layer, and deposit a uniform hole transport layer 4 with a thickness of 50-100 nm using spin coating (3000 rpm, 30 seconds).

[0042] Step 6: Prepare a metal top electrode layer 5 on the hole transport layer 4. Specifically, a metal top electrode is deposited on the surface of the hole transport layer using a thermal evaporation process. Pure gold (Au) is used as the metal material, and a 50-100 nanometer thick gold electrode is uniformly deposited on the hole transport layer 4 under high vacuum conditions using a thermal evaporation device to ensure good contact between the electrode and the hole transport layer 4 and good charge collection capability.

[0043] In this application, the rough surface of tin dioxide nanoparticles provides a large number of high-energy sites, promoting the initial nucleation of two-dimensional perovskite crystals and guiding crystal growth along the vertical direction to minimize surface free energy. Furthermore, the interfacial lattice matching and chemical bonding between the tin dioxide nanoparticles and the perovskite material (such as the interaction between oxygen vacancies and Pb²⁺ and I⁻) further stabilize the vertically oriented growth path. Simultaneously, the bulky organic cations (such as PEA⁺) in the two-dimensional perovskite material tend to stack in layers on the inorganic [PbI₆] due to their steric hindrance effect. 4- The lateral surfaces of the octahedral layers facilitate the vertical stacking of inorganic layers. Furthermore, the solvent distribution and evaporation kinetics on the rough surfaces during spin coating and annealing contribute to the rapid growth of vertical crystals, while the annealing process further optimizes the vertical orientation order through crystal rearrangement and stress release. Ultimately, this vertically oriented crystal structure effectively reduces the number of grain boundaries, improving carrier migration efficiency and photoelectric conversion performance.

[0044] Preferably, after spin-coating tin dioxide nanoparticles, ultrasonic vibration is used on the substrate layer 1 during the annealing process. This ultrasonic vibration mechanically perturbs the nanoparticles, improving the microstructure and interface properties of the film, thereby enhancing the overall performance of the perovskite solar cell. Specifically, ultrasonic vibration during annealing helps rearrange the tin dioxide nanoparticles, increasing interparticle density and reducing porosity and defects in the film, thus forming more uniform and continuous electron transport channels. This density optimization reduces the film's resistance and interface state density, improving carrier extraction efficiency and mobility. Furthermore, ultrasonic vibration can release stress between particles, preventing cracks or particle delamination during thermal annealing, further enhancing the film's mechanical stability and long-term durability. The surface micro-perturbations caused by ultrasonic vibration can also optimize the film's surface roughness, providing more uniform nucleation sites for subsequent two-dimensional perovskite materials, thereby promoting vertically oriented crystal growth and improving the crystal quality of the perovskite absorber layer. This process combines the advantages of heat treatment and acoustic perturbation, which not only improves the conductivity and photoelectric conversion efficiency of the tin dioxide electron transport layer 2, but also reduces interface recombination losses.

[0045] This invention also includes an ultrasonic vibration device, specifically comprising an ultrasonic vibration table, a substrate fixing clamp, and a temperature control system. The ultrasonic vibration table, as the main vibration source, generates high-frequency vibrations through a built-in ultrasonic generator and transfers the vibration energy to the substrate layer fixed to the surface of the vibration table. The substrate is fixed to the vibration table by clamps or vacuum adsorption to ensure the stability of the substrate position during vibration. The device is also equipped with a controllable heating system to provide the required heat treatment temperature (e.g., 100-150 °C) during annealing and simultaneously apply ultrasonic vibrations. The vibration frequency (e.g., 20-50 kHz) and amplitude are adjustable to adapt to the needs of different materials and thin film structures. Through this design, the ultrasonic vibrations during annealing can act uniformly on the substrate and thin film surface, promoting the rearrangement, densification, and stress release of nanoparticles.

[0046] Preferably, the ultrasonic vibration direction is aligned with the normal direction of the substrate 1 surface. Vertical vibration, by applying an upward mechanical impact force to the film, promotes the rearrangement and denser stacking of nanoparticles along the substrate normal direction. Compared to vibrations in other directions, vertical vibration is more effective at filling voids and pores within the film, thus forming a denser electron transport layer. This dense structure reduces resistance in carrier transport paths, improving electron migration efficiency. Furthermore, vertical vibration helps form a rough structure with microscopic undulations on the film surface. This surface roughness provides more high-energy sites for perovskite crystal nucleation and vertically oriented growth, helping to optimize the crystal quality and growth direction of the perovskite layer, thereby reducing grain boundary defects and improving photoelectric conversion efficiency.

[0047] Example 3

[0048] Based on Examples 1 and 2, zinc oxide nanoparticles with a particle size of 10-20 nm were doped into tin dioxide nanoparticles to promote the vertical orientation growth of two-dimensional perovskite materials. Specifically, tin dioxide and zinc oxide nanoparticles were separately dispersed in isopropanol, and then mixed at a mass ratio of 10:1 (zinc oxide accounting for 10 wt%) after ultrasonic stirring to form a homogeneous SnO2-ZnO mixed nanoparticle solution. This mixed solution was then drop-coated onto a cleaned ITO substrate, and a mixed nanoparticle layer was formed using spin-coating (3000 rpm, 30 seconds). Annealing was then performed at 150 °C for 15 minutes to ensure stable particle adhesion and partial embedding. The surface roughness and high-energy nucleation sites of the mixed nanoparticle layer were significantly improved by the doped zinc oxide, while ZnO and [PbI6] were also incorporated. 4- The octahedral lattice matching facilitates the orderly growth of two-dimensional perovskite crystals along the vertical direction. Next, a precursor solution of phenylethylamine iodide (PEAI) and lead iodide (PbI2) was drop-coated onto the surface of a SnO2-ZnO mixed layer. After spin-coating, the layer was annealed at 100 °C for 10 minutes to generate a vertically oriented two-dimensional perovskite material layer ((PEA)2PbI4). The doping of zinc oxide nanoparticles, by optimizing the roughness, interfacial chemistry, and lattice compatibility of the electron transport layer, not only promotes the vertical growth of the perovskite material but also improves carrier transport performance and photoelectric conversion efficiency, providing a new approach for high-efficiency perovskite solar cells.

[0049] Preferably, the electron transport layer 2 is designed as a bilayer nanoparticle structure. Large-diameter tin dioxide nanoparticles (20-30 nm) are used in the lower layer to increase surface roughness and nucleation site density, while small-diameter zinc oxide nanoparticles (5-10 nm) cover the upper layer to further passivate the interface and optimize the crystal nucleation environment, significantly improving the performance of perovskite solar cells. Specifically, the large-diameter tin dioxide particles provide more high-energy sites for the vertical orientation growth of the perovskite crystal by increasing roughness, while the small-diameter zinc oxide particles have good lattice matching and passivation effects, reducing interface defect density, minimizing carrier recombination at the interface, and optimizing the crystal growth environment, further improving the quality of the perovskite crystal and its photoelectric conversion efficiency. The specific preparation method is as follows: First, tin dioxide nanoparticles with a particle size of 20-30 nm are dispersed in isopropanol (concentration of 5 wt%) and uniformly coated onto the cleaned ITO substrate surface by spin coating (3000 rpm, 30 seconds), and then annealed at 150 °C for 15 minutes to form the lower layer structure. Then, zinc oxide nanoparticles with a particle size of 5-10 nm are dispersed in isopropanol (concentration of 2 wt%) and deposited on the tin dioxide layer by the same spin coating method, and annealed again at 150 °C for 10 minutes to form the upper layer structure. Through this bilayer design, the electron transport layer not only has stronger conductivity and better interface quality, but also provides a more ideal foundation for the vertical orientation growth of two-dimensional perovskite materials and subsequent carrier transport.

[0050] In summary, this invention provides a two-dimensional perovskite vertically oriented solar cell and its fabrication method. By optimizing the design of the electron transport layer 2 and the perovskite absorber layer 3, the photoelectric conversion efficiency and device stability of the perovskite solar cell are improved, laying the foundation for further realization of efficient, stable, and scalable perovskite photovoltaic devices. Furthermore, this design concept provides guidance for the research on crystal growth, interface control, and functionalized electron transport layers in perovskite material systems.

[0051] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A two-dimensional perovskite vertically grown solar cell, comprising a substrate layer, an electron transport layer, a perovskite absorber layer, a hole transport layer, and a metal top electrode layer arranged in order from bottom to top, characterized in that, The electron transport layer comprises a tin dioxide film and tin dioxide nanoparticles, the tin dioxide nanoparticles are disposed on the perovskite absorption layer side of the tin dioxide film, the perovskite absorption layer comprises a two-dimensional perovskite material layer and a three-dimensional perovskite material layer, the two-dimensional perovskite material layer is in contact with the tin dioxide nanoparticles, and the three-dimensional perovskite material layer is in contact with the hole transport layer.

2. The two-dimensional perovskite vertically aligned grown solar cell of claim 1, wherein: The thickness of the tin dioxide film is 30-50 nm, and the particle size of the tin dioxide nanoparticles is 5-20 nm.

3. The two-dimensional perovskite vertically aligned grown solar cell of claim 2, wherein: The tin dioxide nanoparticles are partially embedded in the tin dioxide film.

4. The two-dimensional perovskite vertically aligned grown solar cell of claim 1, wherein: The material of the base layer is ITO or FTO, the material of the hole transport layer is Spiro-OMeTAD, and the material of the metal top electrode layer is gold.

5. The two-dimensional perovskite vertically aligned grown solar cell of claim 1, wherein: The tin dioxide nanoparticles are doped with zinc oxide nanoparticles.

6. A method for preparing a two-dimensional perovskite vertically oriented grown solar cell, characterized in that: The method comprises the following steps: Step 1: preparing a tin dioxide film on a base layer; Step 2: disposing tin dioxide nanoparticles on the tin dioxide film; Step 3: preparing a two-dimensional perovskite material layer on the tin dioxide nanoparticles; Step 4: preparing a three-dimensional perovskite material layer on the two-dimensional perovskite material layer; Step 5: preparing a hole transport layer on the three-dimensional perovskite material layer; Step 6: preparing a metal top electrode layer on the hole transport layer.

7. The method for fabricating a two-dimensional perovskite vertically oriented solar cell as described in claim 6, characterized in that: In step 1, a spin coating method is used to prepare a tin dioxide film on ITO.

8. The method for fabricating a two-dimensional perovskite vertically oriented solar cell as described in claim 7, characterized in that: In step 2, a spin coating method is used to spin coat tin dioxide nanoparticles on the tin dioxide film.

9. The method for fabricating a two-dimensional perovskite vertically oriented solar cell as described in claim 8, characterized in that: In step 3, a precursor solution of two-dimensional perovskite material is spin coated on the surface of the tin dioxide nanoparticles, and a two-dimensional perovskite material layer is obtained after annealing.

10. The method for fabricating a two-dimensional perovskite vertically oriented solar cell as described in claim 9, characterized in that: In step 4, a precursor solution of three-dimensional perovskite material is spin coated on the surface of the two-dimensional perovskite material layer, and a three-dimensional perovskite material layer is obtained after annealing.

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