WO2024082991A1

WO2024082991A1 - Two-dimensional/three-dimensional body mixed perovskite solar cell and preparation method therefor

Info

Publication number: WO2024082991A1
Application number: PCT/CN2023/123664
Authority: WO
Inventors: 何博; 秦媛; 李勃超; 王永磊; 刘杨; 张洪旭; 李巧艳; 何永才; 顾小兵; 丁蕾; 谢红刚; 徐希翔
Original assignee: 隆基绿能科技股份有限公司
Priority date: 2022-10-21
Filing date: 2023-10-10
Publication date: 2024-04-25

Abstract

A two-dimensional/three-dimensional body mixed perovskite solar cell comprises a substrate (105); a first carrier transport layer (201), a two-dimensional/three-dimensional body mixed perovskite absorber layer (203), and a second carrier transport layer (204) are stacked in sequence on one side surface of the substrate (105); two-dimensional perovskite seed crystals (2032) and three-dimensional perovskite are provided in the two-dimensional/three-dimensional body mixed perovskite absorber layer (203), and the two-dimensional perovskite seed crystals (2032) are located at the grain boundary of the three-dimensional perovskite and the surface of the three-dimensional perovskite. The two-dimensional perovskite seed crystals (2032) are introduced into the two-dimensional/three-dimensional body mixed perovskite absorber layer (203), so that the defects at the grain boundary and surface of the three-dimensional perovskite can be passivated, the carrier interface separation efficiency is improved, ion migration is inhibited, the environment humidity and thermal stability can be improved, and finally, the requirements of improving the performance of a perovskite/silicon stack device and improving the long-term operating stability of the perovskite/silicon laminated device are satisfied.

Description

A two-dimensional three-dimensional bulk phase hybrid perovskite solar cell and its preparation method

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure claims the priority of the Chinese patent application filed with the Chinese Patent Office on October 21, 2022, with application number 202211296767.4, entitled “A two-dimensional and three-dimensional bulk phase mixed perovskite solar cell and its preparation method”, as well as the priority of the Chinese patent application filed with the Chinese Patent Office on October 21, 2022, with application number 202211293209.2, entitled “A solar cell and its preparation method”, and the priority of the Chinese patent application filed with the Chinese Patent Office on December 26, 2022, with application number 202211675455.4, entitled “A solar cell and its preparation method”, the entire contents of which are incorporated by reference into the present disclosure.

Technical Field

The present application relates to the technical field of solar cells, and in particular to a two-dimensional and three-dimensional bulk phase hybrid perovskite solar cell and a preparation method thereof.

Background technique

Perovskite cells/silicon-based heterojunction two-terminal stacked cells achieve spectral distribution absorption and can obtain a photoelectric conversion efficiency of more than 30% (＞silicon cell limit efficiency 29.4%), which is considered to be the mainstream product of low-cost and high-efficiency solar cells in the future. To achieve long-term stable operation of perovskite/silicon stacked cell devices, the long-term stability of perovskite cells is crucial. There are two main reasons for the instability of perovskite cells: the perovskite layer in the perovskite cell is susceptible to water, oxygen and thermal erosion, which induces the deconstruction of the perovskite structure, resulting in deterioration of long-term working stability; the halogen ions (I, Br, Cl) and metal ions (Pb, Sn, etc.) in the perovskite layer will produce ion migration due to defects in the perovskite layer and the internal electric field of the device, resulting in component mismatch and electrode corrosion in the perovskite layer, which ultimately deteriorates the long-term working stability of the perovskite cell.

The development of solar cells for clean and renewable energy is driven by the reduction of the levelized cost of electricity (LCOE). Improving the power conversion efficiency (PCE) of solar panels can not only generate more electricity, but also reduce related costs such as transportation, installation, land use, etc., which helps to reduce LCOE. However, perovskite cells prepared by traditional methods usually use three-dimensional perovskites, which are easily decomposed by the influence of moisture and oxygen in the air, resulting in poor stability of solar cells.

Silicon-based solar cells dominate the terrestrial solar panel market with an average PCE of around 20%. Record cell efficiencies have approached the Shockley-Quiesser (SQ) limit of single-junction solar cells, and thin-film solar cells based on copper indium gallium selenide (CIGS) and cadmium telluride (CdTe) have also developed rapidly in the past 20 years. However, the PCE of single-junction solar cells cannot exceed the SQ limit due to below-bandgap absorption losses and thermal relaxation losses of hot carriers. Tandem solar cells, which integrate low-cost, high-efficiency wide-bandgap top solar cells with low-bandgap (e.g., Si, CIGS, CdTe, etc.) bottom solar cells, are more efficient than single-junction solar cells because they can better utilize the energy of short-wavelength photons in the sunlight spectrum. The top cell composed of a high-bandgap semiconductor generates photocurrent from the short-wavelength part of the solar spectrum at high voltage. Longer wavelength light, exceeding the bandgap of the top cell, is transmitted to the bottom cell composed of a low-bandgap semiconductor with a wide absorption coefficient. The efficiency potential of tandem cells makes them the most likely candidate for continued and substantial price reductions in photovoltaic modules over the next few decades. However, the perovskite cells prepared by traditional methods usually use three-dimensional perovskites, which are easily decomposed by the influence of moisture and oxygen in the air, resulting in poor stability of solar cells. In the prior art, a two-dimensional perovskite layer can be formed on the three-dimensional perovskite layer to play a passivation role. However, the two-dimensional phase is distributed on the surface of the three-dimensional perovskite layer, which makes electron transmission difficult, the passivation effect is not significant, the water vapor barrier effect is weak, and the overall device performance is low.

Summary of the invention

In response to the above problems, the present application proposes a two-dimensional three-dimensional bulk phase hybrid perovskite solar cell. In the two-dimensional three-dimensional bulk phase hybrid perovskite absorption layer, a two-dimensional perovskite seed crystal is introduced, which not only passivates the defects of the three-dimensional perovskite grain boundary and surface, improves the carrier interface separation efficiency, and inhibits ion migration, but also improves its environmental humidity and thermal stability, ultimately achieving the purpose of improving the performance of perovskite/silicon stacked devices and improving their long-term working stability.

The technical solution of this application is as follows:

The present application provides a two-dimensional three-dimensional bulk phase hybrid perovskite solar cell, comprising a substrate, wherein a first carrier transport layer, a two-dimensional three-dimensional bulk phase hybrid perovskite absorption layer and a second carrier transport layer are sequentially stacked on a surface of one side of the substrate;

The two-dimensional and three-dimensional bulk mixed perovskite absorption layer contains two-dimensional perovskite seed crystals and three-dimensional perovskite, and the two-dimensional perovskite seed crystals are located at the grain boundaries of the three-dimensional perovskite and the surface of the three-dimensional perovskite.

Furthermore, the particle size distribution of the two-dimensional perovskite seed crystal is 20nm-200nm.

Furthermore, in the two-dimensional three-dimensional bulk mixed perovskite absorption layer, the two-dimensional perovskite seed The crystal content is 0.1%-5%;

The content of the three-dimensional perovskite is 95%-99.9%; or

The particle size distribution of the two-dimensional perovskite seed crystals is 140-170 nm, accounting for more than 90%.

Furthermore, the substrate has a velvet structure, and the first carrier transport layer, the two-dimensional and three-dimensional bulk mixed perovskite absorption layer, and the second carrier transport layer are all conformal to the velvet structure of the substrate.

Furthermore, the suede structure is randomly or regularly distributed on at least one surface of the substrate;

The basic shape of the velvet structure is selected from one or more of a columnar shape, a cone shape, a table shape, an arc-shaped groove or an arc-shaped protrusion.

Furthermore, the thickness of the two-dimensional three-dimensional bulk mixed perovskite absorption layer is 350-700nm.

Furthermore, the substrate is a silicon-based battery.

The present application provides a method for preparing a two-dimensional three-dimensional bulk hybrid perovskite solar cell, comprising the following steps:

providing a substrate;

forming a first carrier transport layer on the surface of the substrate;

Forming a two-dimensional and three-dimensional bulk mixed perovskite absorption layer on a surface of the first carrier transport layer facing away from the substrate;

Forming a second carrier transport layer on a surface of the two-dimensional and three-dimensional bulk mixed perovskite absorption layer that is away from the first carrier transport layer;

The two-dimensional and three-dimensional bulk mixed perovskite absorption layer contains two-dimensional perovskite seed crystals and three-dimensional perovskite, and the two-dimensional perovskite seed crystals are located at the grain boundaries of the three-dimensional perovskite.

Furthermore, the two-dimensional three-dimensional bulk mixed perovskite absorption layer is formed by the following method:

forming a mixed layer containing lead halide on a surface of the first carrier transport layer facing away from the substrate;

forming a two-dimensional perovskite seed crystal on a surface of the mixed layer facing away from the first carrier transport layer;

A three-dimensional perovskite precursor solution is spin-coated on the surface of the mixed layer having the two-dimensional perovskite seed crystal, and the three-dimensional perovskite precursor solution reacts with the mixed layer to obtain a two-dimensional three-dimensional bulk mixed perovskite absorption layer.

Furthermore, a mixed layer containing lead halide is formed on a surface of the first carrier transport layer facing away from the substrate by a dual-source co-evaporation method or a vapor deposition method.

Furthermore, the thickness of the mixed layer is 200-500 nm.

In the mixed layer, the content of the lead halide is 95%-99%.

Furthermore, an organic amine salt is added to a mixed solvent formed by a perovskite antisolvent and isopropanol to form a mixed solution 1, and the mixed solution 1 is spin-coated on a surface of the mixed layer facing away from the substrate, and the mixed solution 1 reacts with the mixed layer to generate a two-dimensional perovskite seed crystal.

Further, in the mixed solution 1, the molar concentration of the organic amine salt is 0.05mM to 0.7mM, or

The volume ratio of the perovskite antisolvent to isopropanol is (1.5-9):1.

Furthermore, the perovskite antisolvent is at least one of diethyl ether, chlorobenzene, ethyl acetate and benzamidine.

forming a two-dimensional perovskite seed crystal on a surface of the first carrier transport layer facing away from the substrate;

forming a mixed layer containing lead halide on a surface of the first carrier transport layer having the two-dimensional perovskite seed crystal;

A three-dimensional perovskite precursor solution is spin-coated on the surface of the mixed layer on the side away from the first carrier transport layer, and the three-dimensional perovskite precursor solution reacts with the mixed layer to obtain a two-dimensional and three-dimensional bulk mixed perovskite absorption layer.

Furthermore, the two-dimensional perovskite seed crystal is prepared by the following steps:

An organic amine salt is mixed with a lead halide to form a two-dimensional perovskite precursor, and then a mixed solvent formed by a perovskite antisolvent and DMF is added to the two-dimensional perovskite precursor to form a second mixed solution, and the second mixed solution is spin-coated on a side surface of the first carrier transport layer facing away from the substrate, thereby forming a two-dimensional perovskite seed crystal on the side surface of the first carrier transport layer.

Further, in the second mixed solution, the molar concentration of the two-dimensional perovskite precursor is 0.05 mM to 0.4 mM, or

The volume ratio of the perovskite anti-solvent to DMF is (1.5-9):1.

Further, the organic amine salt is selected from at least one of benzyl ammonium hydrohalide, γ-fluorobenzyl ammonium hydrohalide, phenethyl ammonium hydrohalide, γ-fluorophenethyl ammonium hydrohalide, n-butylamine hydrohalide, isobutylamine hydrohalide, halobutylammonium hydrohalide, halopropylammonium hydrohalide or 1-naphthylamine hydrohalide.

Furthermore, the perovskite anti-solvent is at least one of tetrahydrofuran, acetonitrile, and dimethoxyethanol.

Furthermore, a dual-source co-evaporation method or a vapor deposition method is used to form a mixed layer containing lead halide covering the two-dimensional perovskite seed crystal on the surface of one side of the first carrier transport layer having the two-dimensional perovskite seed crystal.

Further, the thickness of the mixed layer is 200-500nm;

In the mixed layer, the content of the lead halide is 95%-99%.

Furthermore, the two-dimensional three-dimensional bulk phase hybrid perovskite solar cell prepared by the method is the aforementioned two-dimensional three-dimensional bulk phase hybrid perovskite solar cell.

The two-dimensional and three-dimensional bulk phase hybrid perovskite solar cell provided in the present application has two-dimensional perovskite seed crystals and three-dimensional perovskite in the two-dimensional and three-dimensional bulk phase hybrid perovskite absorption layer, and part of the two-dimensional perovskite seed crystals are located at the upper and lower interfaces of the three-dimensional perovskite, and part of the two-dimensional perovskite seed crystals remain at the grain boundaries between the three-dimensional perovskite bulk phase grains. The introduction of the two-dimensional perovskite seed crystals can passivate the three-dimensional perovskite grain boundary defects, improve the carrier interface separation efficiency, inhibit ion migration, and improve its environmental humidity and thermal stability, thereby ultimately achieving the needs of improving the performance of perovskite/silicon stacked devices and improving their long-term working stability.

The preparation method provided in this application adopts two methods and three steps to introduce two-dimensional perovskite into three-dimensional perovskite, induce directional crystallization of three-dimensional perovskite and form a two-dimensional and three-dimensional bulk mixed perovskite absorption layer, solving the defect passivation problem of the perovskite layer in the perovskite/silicon suede stacked battery.

The present application proposes a solar cell that can not only improve the stability of the solar cell but also ensure the efficiency of the solar cell.

The technical solution of this application is as follows:

The present application provides a solar cell, comprising a perovskite composite layer, wherein the perovskite composite layer comprises a two-dimensional perovskite layer and a three-dimensional perovskite layer stacked;

At least part of the two-dimensional perovskite in the two-dimensional perovskite layer is arranged along an interface perpendicular to the three-dimensional perovskite layer and the two-dimensional perovskite layer.

Furthermore, in the two-dimensional perovskite layer, at least part of the two-dimensional perovskite is arranged along an interface parallel to the three-dimensional perovskite layer and the two-dimensional perovskite layer.

Further, in the two-dimensional perovskite layer, the two-dimensional perovskite perpendicular to the interface is the first two-dimensional perovskite Titanium ore, the two-dimensional perovskite parallel to the interface is a second two-dimensional perovskite, and the content of the first two-dimensional perovskite layer gradually decreases from a side surface close to the three-dimensional perovskite layer to a side surface far from the three-dimensional perovskite layer.

Furthermore, in the two-dimensional perovskite layer, the content of the second two-dimensional perovskite layer gradually increases from a surface side close to the three-dimensional perovskite layer to a surface side far from the three-dimensional perovskite layer.

Furthermore, in the two-dimensional perovskite layer, a ratio of a content of the first two-dimensional perovskite to a content of the second two-dimensional perovskite is (1-4):1.

Furthermore, the solar cell further comprises a substrate, and the substrate has a smooth surface or a velvet structure.

Furthermore, when the substrate has a velvet structure, both the three-dimensional perovskite layer and the two-dimensional perovskite layer are conformal to the substrate.

Furthermore, the band gap of the perovskite composite layer is 1.65-1.69 eV.

The present application provides a method for preparing a solar cell, comprising the following steps:

Preparation of three-dimensional perovskite layers;

preparing a two-dimensional perovskite layer on the surface of the three-dimensional perovskite layer;

Furthermore, an organic amine salt solution is coated on the surface of the three-dimensional perovskite layer, and the organic amine salt solution reacts with residual lead halide in the three-dimensional perovskite layer to generate a two-dimensional perovskite layer.

Furthermore, the organic amine salt solution and the surface of the three-dimensional perovskite layer are heated respectively, and then the heated organic amine salt solution is spin-coated on the surface of the heated three-dimensional perovskite layer. After the spin coating is completed, annealing is performed to form a two-dimensional perovskite layer.

Furthermore, the organic amine salt solution is formed by dissolving an organic amine salt in a solvent.

Furthermore, the organic amine salt solution is formed by dissolving an organic amine salt and an additive in a solvent.

Furthermore, the organic amine salt solution is formed by mixing an organic amine salt, a first solvent and a second solvent.

Further, the organic amine salt is selected from RP type organic amine salt, DJ type organic amine salt or ACI type organic amine salt;

The concentration of the organic amine salt in the organic amine salt solution is 0.2-0.5 mol/l;

The first solvent is isopropanol or ethanol;

The second solvent is chlorobenzene, ethyl acetate, toluene, N-methylpyrrolidone, and γ-butyrolactone;

The volume ratio of the solvent 1 to the solvent 2 is (2-9):1.

Further, the additive is one of ammonium chloride, ammonium thiocyanate, methylammonium chloride, and ammonium thiocyanate;

The concentration of the additive is 2-15 mg/mL.

Furthermore, the prepared solar cell is the aforementioned solar cell.

The solar cell provided by the present application has a two-dimensional perovskite layer in the perovskite composite layer, and the two-dimensional perovskite can improve the stability of the perovskite cell; at the same time, since the two-dimensional perovskite layer also includes a first two-dimensional perovskite, the first two-dimensional perovskite is arranged in a direction perpendicular to the three-dimensional perovskite layer and close to the interface of the two-dimensional perovskite layer, so the first two-dimensional perovskite can also promote electron transmission between the two-dimensional perovskite layer and the three-dimensional perovskite layer, thereby improving the device efficiency.

In response to the above problems, the present application proposes a solar cell having a two-dimensional three-dimensional bulk phase mixed perovskite absorption layer, in which the two-dimensional perovskite is uniformly dispersed in the three-dimensional perovskite. The two-dimensional perovskite can better passivate the defects at the grain boundaries of the three-dimensional perovskite, thereby obtaining enhanced water vapor barrier capability and electron transmission efficiency, thereby improving the stability of the solar cell and the battery performance.

The present application provides a solar cell, comprising a substrate, wherein a first carrier transport layer, a two-dimensional three-dimensional bulk mixed perovskite absorption layer and a second carrier transport layer are sequentially stacked on a surface of one side of the substrate;

The two-dimensional and three-dimensional bulk mixed perovskite absorption layer contains two-dimensional perovskite and three-dimensional perovskite, and the two-dimensional perovskite is uniformly dispersed in the three-dimensional perovskite.

Furthermore, the mass ratio of the two-dimensional perovskite to the three-dimensional perovskite is 1:(2-9).

Furthermore, the grain size distribution of the two-dimensional perovskite accounts for more than 90% of the grain size distribution in the range of 80-150 nm.

Furthermore, the grain size distribution of the three-dimensional perovskite accounts for more than 90% in the range of 500-800 nm.

Furthermore, the substrate is a silicon-based battery or a glass substrate.

preparing a substrate;

forming a first carrier transport layer on one side of the substrate;

Preparing a three-dimensional perovskite precursor solution;

Adding organic amine and hydrohalic acid to the three-dimensional perovskite precursor solution and mixing them evenly to obtain a mixed solution;

The mixed solution is applied to a surface of the first carrier transport layer that is away from the substrate, thereby forming the two-dimensional and three-dimensional bulk mixed perovskite absorption layer.

Furthermore, the application is spin coating, and an anti-solvent is dripped onto the surface coated with the mixed solution before the spin coating is completed, thereby forming the two-dimensional three-dimensional bulk mixed perovskite absorption layer.

Furthermore, the volume ratio of the mixed solution of the organic amine and the hydrohalic acid to the perovskite precursor solution is 1:(45-65), preferably 1:(48-52).

Furthermore, the volume ratio of the hydrohalic acid to the organic amine is (0.7-1.2:1), preferably (0.9-1.1):1.

Furthermore, the hydrohalic acid is selected from one of hydroiodic acid, hydrobromic acid or hydrochloric acid.

Further, the organic amine is selected from one of benzylamine, γ-fluorobenzylamine, phenethylamine, γ-fluorophenethylamine, n-butylamine, isobutylamine, halobutylamine, halopropylamine or 1-naphthylamine.

Furthermore, the perovskite precursor solution is a ternary perovskite precursor solution.

Furthermore, the prepared solar cell is the aforementioned solar cell.

The solar cell provided by the present application has a two-dimensional and three-dimensional bulk mixed perovskite absorption layer having two-dimensional perovskite and three-dimensional perovskite, and the two-dimensional perovskite is uniformly dispersed in the three-dimensional perovskite. The applicant has found that by adopting such a design, the two-dimensional perovskite can better passivate the defects at the grain boundaries of the three-dimensional perovskite, obtain enhanced water vapor barrier capability and electron transmission efficiency, thereby improving the stability of the solar cell and the battery performance.

The method for preparing solar cells provided in the present application, by adding hydrohalic acid and organic amine into a three-dimensional perovskite precursor solution, the applicant found that such a design forms a two-dimensional perovskite in the three-dimensional perovskite precursor solution, and the two-dimensional perovskite can be evenly distributed in the three-dimensional perovskite film, playing a role in passivating the three-dimensional perovskite grain boundaries. At the same time, it also solves the problems of complex preparation process and low purity of organic amine salts in the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are used to better understand the present application and do not constitute an improper limitation on the present application.

FIG1 is a schematic diagram of the structure of a two-dimensional and three-dimensional bulk hybrid perovskite solar cell provided in the present application.

FIG2 is a comparison of SEM images of the perovskite absorption layer of the two-dimensional and three-dimensional bulk phase hybrid perovskite solar cell prepared in Example 1 provided in the present application and the solar cell prepared in the comparative example and the comparative example.

FIG3 is a stability curve diagram of the two-dimensional and three-dimensional bulk hybrid perovskite solar cell prepared in Example 1 provided in the present application and the comparative example.

FIG4 is a carrier lifetime curve diagram of the two-dimensional and three-dimensional bulk hybrid perovskite solar cell prepared in Example 1 provided in the present application and the comparative example.

FIG5 is a schematic diagram of the structure of a solar cell provided in the present application.

FIG. 6 is a schematic diagram of the structure of a solar cell provided in the present application.

FIG. 7 is a schematic diagram of a partial structure of a solar cell provided in the present application.

FIG8 is a schematic diagram of a partial structure of a solar cell provided in the present application.

FIG. 9 is a schematic diagram of a two-dimensional and three-dimensional bulk mixed perovskite absorption layer provided in the present application.

FIG. 10 is a schematic diagram of the structure of a solar cell provided in the present application.

FIG. 11 is a PL test comparison diagram of a two-dimensional three-dimensional bulk mixed perovskite absorption layer and a three-dimensional perovskite absorption layer provided in the present application.

Description of Reference Numerals

100-silicon-based cell, 101-light-absorbing layer, 102-tunneling layer, 103-metal electrode, 1011-pyramid velvet structure, 200-perovskite top cell, 201-first carrier transport layer, 2031-mixed layer, 2032-two-dimensional perovskite seed crystal, 203-two-dimensional three-dimensional bulk mixed perovskite absorption layer, 204-second carrier transport layer, 205-buffer layer, 206-transparent conductive layer, 207-anti-reflection layer. 105-substrate, 1031-first metal electrode, 202-three-dimensional perovskite layer, 208-two-dimensional perovskite layer, 2081-second two-dimensional perovskite, 2082-first two-dimensional perovskite, 209-second transparent conductive layer, 1032-second metal electrode. 1-first metal electrode layer, 2-first transparent conductive layer, 3-first doped layer, 4-first passivation layer, 5-silicon substrate, 6-second passivation layer, 7-second doped layer, 8-composite layer, 13-second metal electrode layer.

Specific embodiments

The following is a description of the exemplary embodiments of the present application, including various details of the embodiments of the present application to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. Similarly, for the sake of clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

Single-cell perovskite solar cells usually use physical packaging of the entire device in combination with interface modification and bulk passivation inside the perovskite device to solve the problem of long-term working stability. Among them, two-dimensional and three-dimensional bulk hybrid perovskites are a common strategy to improve the working stability of perovskite devices through interface modification and bulk passivation. However, the two-dimensional three-dimensional bulk phase mixed perovskite passivation strategy is mostly adopted in single-cell perovskite solar cells, and there are very few reports on its use in perovskite/silicon stacked cells, especially perovskite/silicon velvet stacked cell devices. There is no successful application precedent. The main reason is that the two-dimensional three-dimensional bulk phase mixed perovskite usually uses a one-step solution method such as spin coating, scraping, and spraying to plant two-dimensional perovskite seed crystals on a flat substrate with a two-dimensional perovskite precursor solution, and then continues to use a one-step solution method such as spin coating, scraping, and spraying to prepare a two-dimensional three-dimensional bulk phase mixed perovskite layer. However, the one-step solution method is difficult to deposit a two-dimensional three-dimensional bulk phase mixed perovskite layer on the velvet pyramid of a silicon bottom cell, especially when the height of the silicon velvet pyramid is ≥3μm, it is difficult for the two-dimensional perovskite seed crystal to be planted alone on the pyramid velvet. Even if the planting is successful, the subsequent one-step solution method will dissolve the previously planted two-dimensional perovskite seed crystals or the two-dimensional perovskite seed crystals will be distributed at the interface of the three-dimensional perovskite and the transport layer when the perovskite layer is prepared, and the two-dimensional three-dimensional bulk phase mixed perovskite film cannot be obtained. Therefore, the existing two-dimensional three-dimensional bulk phase mixed perovskite passivation strategy is difficult to apply in perovskite/silicon velvet stacked battery devices. After long-term research, the inventors of this application found that a mixed layer containing lead halide that is conformal to the velvet is deposited on the velvet of the silicon bottom battery pyramid, and then a two-dimensional perovskite seed crystal is planted on the mixed layer that is conformal to the velvet or a two-dimensional perovskite seed crystal is planted before the mixed layer is formed, and finally a two-dimensional perovskite seed crystal is used to induce the three-dimensional perovskite to crystallize into a film, and finally a two-dimensional three-dimensional bulk phase mixed perovskite is formed, thereby introducing a two-dimensional three-dimensional bulk phase mixed perovskite passivation strategy into a perovskite/silicon velvet stacked device to improve the overall stacking. Therefore, the present application aims to introduce two-dimensional and three-dimensional bulk mixed perovskite on the pyramid velvet of silicon-based cells to passivate three-dimensional perovskite film defects, inhibit ion migration, improve environmental stability, and ultimately improve the performance of perovskite/silicon velvet stacked cells and improve their long-term working stability.

A two-dimensional three-dimensional bulk phase hybrid perovskite solar cell provided in the present application includes a substrate, and a first carrier transport layer, a two-dimensional three-dimensional bulk phase hybrid perovskite absorption layer and a second carrier transport layer are sequentially stacked on a surface of one side of the substrate;

The two-dimensional three-dimensional bulk mixed perovskite absorption layer contains two-dimensional perovskite seed crystals and three-dimensional perovskite, and the two-dimensional perovskite seed crystals are located at the grain boundaries of the three-dimensional perovskite.

In the present application, the two-dimensional perovskite seed crystal is formed independently before the three-dimensional perovskite, so the two-dimensional perovskite seed crystal and the three-dimensional perovskite are two perovskite materials with different components, different structures, different morphologies and generated at different times. The two-dimensional perovskite seed crystal will not enter the interior of the three-dimensional perovskite lattice, nor will it change the three-dimensional perovskite component. The existence of the two-dimensional perovskite seed crystal is to induce the formation of a three-dimensional perovskite with a better morphology. During the growth of the three-dimensional perovskite, part of the two-dimensional perovskite seed crystal squeezes toward the upper and lower interfaces of the three-dimensional perovskite film layer, and part of the two-dimensional perovskite seed crystal remains at the grain boundary between the three-dimensional perovskite bulk phase grains. In this way, the two-dimensional perovskite seed crystal passivates both the three-dimensional perovskite grain boundary and the surface of the three-dimensional perovskite. At the same time, because the two-dimensional perovskite seed crystal remaining on the surface is better resistant to water and oxygen in the external environment, the three-dimensional perovskite is isolated from direct contact with subsequent other layers, thereby inhibiting ion migration and improving stability. Two-dimensional perovskite seed crystals induce the growth of three-dimensional perovskite, and the seed crystal particle size is in the range of 20nm-200nm. The seed crystal particle size cannot be too small. If it is too small, the three-dimensional perovskite nucleation sites will increase, and the three-dimensional perovskite grains will become more and smaller in size, which is not conducive to improving the performance of perovskite; if the seed crystal particle size is too large, the number of seed crystals formed will be too small, and the three-dimensional perovskite nucleation and growth cannot be induced; and the content of two-dimensional perovskite seed crystals cannot be too much, because the photoelectric performance of two-dimensional perovskite is worse than that of three-dimensional perovskite. Therefore, the size of two-dimensional perovskite seed crystals is increased within a limited content while maintaining the number of two-dimensional perovskite seed crystals.

In the present application, the particle size distribution of the two-dimensional perovskite seed crystal is 20nm-200nm, for example, it can be 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 11nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm or 200nm.

The size of the two-dimensional perovskite seed crystals is non-uniform and irregular in layer shape, with 90% of them having a particle size of 140-170nm.

The size of the two-dimensional perovskite seed crystals in the two-dimensional and three-dimensional bulk mixed perovskite absorber layer can be detected by dynamic light scattering (DLS), scanning electron microscopy (SEM), particle size analyzer (PSA) and other means.

The general structure of three-dimensional perovskites is ABX3, with six halide anions (X sites; e.g., I-, Br-, and Cl-) forming a _BX6 octahedral framework with divalent metal cations (B sites; e.g., ^Sn2+ and Pb2 ⁺ ). Twelve monovalent cations (A sites; e.g., MA ⁺ , FA ⁺ , and Cs ⁺ ) occupy the centers of four _BX6 octahedra. Two-dimensional perovskites are often described by the formula (A') _m (A) _n- _1BnX3n ₊₁ , where a divalent (m=1) or monovalent (m=2) cation forms a bilayer or monolayer of connected inorganic (A) _n- _1BnX3n ₊₁ sheets, where n represents the thickness of the metal halide layer, which can be controlled by optimizing the precursor composition. In general, the organic A-site cations can be arbitrarily long, allowing the use of large, high-aspect-ratio cations (e.g., aliphatic or aromatic cations). The geometric structure of the two-dimensional octahedral arrangement usually contains a BX ₄ ^2- inorganic unit. In addition, the negative charge of a negative ion needs a positive charge to balance (for example, A ₂ 'BX ₄ , when n = 2, A' is a monovalent cation). n = ∞ corresponds to a three-dimensional perovskite, while n = 1 represents a pure two-dimensional perovskite, and 1 < n ≤ 5 is usually called a quasi-two-dimensional perovskite.

In the present application, in the two-dimensional and three-dimensional bulk mixed perovskite absorption layer, the content of the two-dimensional perovskite seed crystal is 0.1%-5%; the content of the three-dimensional perovskite is 95%-99.9%.

Specifically, the two-dimensional perovskite seed crystals may be 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9% or 5%.

Specifically, the content of the three-dimensional perovskite can be 95%, 95.1%, 95.2%, 95.3%, 95.4%, 95.5%, 95.6%, 95.7%, 95.8%, 95.9%, 96%, 96.1%, 96.2%, 96.3%, 96.4%, 96.5%, 96.6%, 96.7%, 96.8%, 96.9%, 97%, 97.1%, 97.2%, 97.3% , 97.4%, 97.5%, 97.6%, 97.7%, 97.8%, 97.9%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or 99.9%.

In the two-dimensional and three-dimensional bulk mixed perovskite absorption layer, when the content of two-dimensional perovskite seed crystals is high and the content of three-dimensional perovskite is low, the stability of the solar cell is relatively high compared with the pure three-dimensional perovskite layer, but the battery efficiency is relatively low. Conversely, when the content of two-dimensional perovskite seed crystals is low and the content of three-dimensional perovskite is high, the stability of the solar cell is relatively low compared with the pure two-dimensional perovskite layer, but the battery efficiency is relatively high. Higher.

In a specific embodiment, when a solar cell with higher battery efficiency is required, the content of two-dimensional perovskite seed crystals in the two-dimensional and three-dimensional bulk mixed perovskite absorption layer is 1%-2%, for example, it can be 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 2%.

In another specific embodiment, when a solar cell with higher stability is required, the content of the two-dimensional perovskite seed crystal in the two-dimensional and three-dimensional bulk mixed perovskite absorption layer is 2%-5%, for example, it can be 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9% or 5%.

The content of two-dimensional perovskite seed crystals and three-dimensional perovskite in the two-dimensional and three-dimensional bulk mixed perovskite absorption layer of the present application can be adjusted according to actual needs.

In the present application, the substrate is a silicon-based cell, that is, a two-dimensional three-dimensional bulk phase mixed perovskite solar cell as shown in Figure 1. The solar cell includes a silicon-based cell and a perovskite top cell. The silicon-based cell includes a light absorbing layer and a tunneling layer stacked together in sequence from bottom to top. The perovskite top cell includes a first carrier transport layer, a two-dimensional three-dimensional bulk phase mixed perovskite absorption layer and a second carrier transport layer, a buffer layer, a transparent conductive layer and an anti-reflection layer in order from bottom to top. The surface of the first carrier transport layer facing away from the two-dimensional three-dimensional bulk phase mixed perovskite absorption layer is stacked together with the surface of the tunneling layer facing away from the light absorbing layer. The tunneling layer, the first carrier transport layer, the two-dimensional three-dimensional bulk phase mixed perovskite absorption layer, the second carrier transport layer, the buffer layer, the transparent conductive layer and the anti-reflection layer are all conformal to the velvet structure. The solar cell also includes a metal electrode, a metal electrode is arranged on the surface of the light absorbing layer facing away from the tunneling layer, and a metal electrode penetrating the anti-reflection layer and connected to the transparent conductive layer is arranged on the surface of the anti-reflection layer facing away from the transparent conductive layer.

The first carrier transport layer can be a hole transport layer or an electron transport layer, and the conductivity types of the first carrier transport layer and the second carrier transport layer are opposite. When the first carrier transport layer is a hole transport layer, it can be a molybdenum oxide layer, a [bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) layer, a copper iodide layer or a Spiro-OMeTAD (2,2',7,7'-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene Chinese name is 2,2',7,7'-tetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene) layer, a PEDOT layer, a PEDOT:PSS layer, a P3HT layer, a P3OHT layer, a P3ODDT layer, a NiOx layer or a CuSCN layer. The second carrier transport layer is an electron transport layer, which can be a titanium oxide layer, a tin oxide layer, a C60 layer or a C60-PCBM layer, a [60]PCBM ([6,6]-phenyl-C61 butyric acid methyl ester, Chinese name is [6,6]-phenyl-C61-butyric acid isomethyl ester) layer, a [70]PCBM ([6, 6]-Phenyl-C71-butyric acid methyl ester, Chinese name is [6,6]-phenyl-C71-butyric acid isomethyl ester) layer, bis[60]PCBM (Bis(1-[3-(methoxycarbonyl)propyl]-1-phenyl)-[6,6]C62) layer, [60]ICBA(1',1",4',4"-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2",3"][5,6]fullerene-C60) layer, etc., including but not limited to these, as long as the functions in the present application can be achieved.

When the first carrier transport layer is an electron transport layer, it can be a titanium oxide layer, a tin oxide layer, a C60 layer or a C60-PCBM layer, a [60]PCBM ([6,6]-phenyl-C61 butyric acid methyl ester, Chinese name is [6,6]-phenyl-C61-butyric acid isomethyl ester) layer, a [70]PCBM ([6,6]-Phenyl-C71-butyric acid methyl ester, Chinese name is [6,6 ]-phenyl-C71-butyric acid isomethyl ester) layer, bis[60]PCBM (Bis(1-[3-(methoxycarbonyl)propyl]-1-phenyl)-[6,6]C62) layer, [60]ICBA(1',1",4',4"-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2",3"][5,6]fullerene-C60) layer, etc. The second carrier transport layer 204 is a hole transport layer, which can be a molybdenum oxide layer, a [bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) layer, a copper iodide layer or a Spiro-OMe TAD (2,2',7,7'-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene Chinese name is 2,2',7,7'-tetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene) layer, a PEDOT layer, a PEDOT:PSS layer, a P3HT layer, a P3OHT layer, a P3ODDT layer, a NiOx layer or a CuSCN layer. Including but not limited to this, as long as the functions in the present application can be achieved.

The thickness of the first carrier transport layer is 10-15 nm, for example, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm or 15 nm.

The thickness of the second carrier transport layer is 10-15 nm, for example, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm or 15 nm.

The buffer layer is used for the longitudinal transport of carriers and protects the perovskite absorption layer from being damaged by sputtering in the subsequent PVD process. The buffer layer may be a SnO2 layer or a TiO2 layer with a thickness of 5-30 nm, for example, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, 28 nm, 29 nm or 30 nm.

The transparent conductive layer can be a transparent conductive film, specifically fluorine-doped tin oxide (FTO), indium tin oxide (ITO) or aluminum-doped zinc oxide (AZO), etc.; the thickness of the transparent conductive layer 206 is 1-20nm, for example, it can be 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm, 15nm, 16nm, 17nm, 18nm, 19nm or 20nm.

The anti-reflection layer 207 may be MgF ₂ , LiF, SiO ₂ , etc., and may have a thickness of 50-300 nm, for example, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm or 300 nm.

The metal electrode can be made of one or more of metal materials such as Ag, Au, Cu, Al, Ni, C materials, and polymer conductive materials.

The light absorbing layer may be a silicon wafer, and further may be a commercial grade M2n-type silicon wafer, with a resistivity of 1-10Ω.cm and a thickness of 150-200μm, for example, 150μm, 160μm, 170μm, 180μm, 190μm or 200μm.

The tunneling layer can be formed by depositing a uc-Si-p ⁺ layer and a uc-Si-n ⁺ layer respectively using PECVD to form a tunneling junction, and its thickness is 15-50nm, for example, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm or 50nm.

In the present application, the suede structure is randomly or regularly distributed on at least one surface of the substrate;

The basic shape of the velvet structure is selected from one or more of a column, a cone, a table, an arc groove or an arc protrusion. For example, it can be a positive or negative triangular prism, a quadrangular prism, a hexagonal prism, a cylindrical, a cone, a triangular pyramid, a quadrangular pyramid, a truncated table, a triangular prism, a quadrangular table, a semicircular groove or a semicircular protrusion.

The suede structure may be composed of one or more of a plurality of columnar, conical, terraced, arc-shaped grooves or arc-shaped protrusions.

In the present application, the height of the textured structure is h, where h≥3 μm.

In this application, conformal means the same shape, that is, in this application, the tunneling layer, the first carrier transport layer, the two-dimensional three-dimensional bulk mixed perovskite absorption layer, the second carrier transport layer, the buffer layer, the transparent conductive layer and the anti-reflection layer all have a suede structure. The main purpose of maintaining the suede structure is to continue the light trapping design of the silicon bottom cell and minimize the light reflection loss.

In the present application, the thickness of the two-dimensional three-dimensional bulk phase mixed perovskite absorption layer is 350-700nm, for example, it can be 350nm, 360nm, 370nm, 380nm, 390nm, 400nm, 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm, 490nm, 500nm, 510nm, 520nm, 530nm, 540nm, 550nm, 560nm, 570nm, 580nm, 590nm, 600nm, 610nm, 620nm, 630nm, 640nm, 650nm, 660nm, 670nm, 680nm, 690nm or 700nm.

The present invention provides a method for preparing a two-dimensional and three-dimensional bulk phase hybrid perovskite solar cell, comprising: Next steps:

Step 1: providing a substrate;

Step 2: forming a first carrier transport layer on a surface of one side of the substrate;

Step 3: forming a two-dimensional and three-dimensional bulk mixed perovskite absorption layer on the surface of the first carrier transport layer facing away from the substrate;

Step 4: forming a second carrier transport layer on a surface of the two-dimensional and three-dimensional bulk mixed perovskite absorption layer that is away from the first carrier transport layer;

The two-dimensional three-dimensional bulk mixed perovskite absorption layer contains two-dimensional perovskite seed crystals and three-dimensional perovskite, and the two-dimensional perovskite seed crystals are located at the grain boundaries of the three-dimensional perovskite;

The particle size distribution of the two-dimensional perovskite seed crystals is 20nm-500nm.

In step one, the silicon wafer undergoes polishing, texturing, coating, cleaning and tunnel junction procedures in sequence to form a silicon-based battery with a texturing structure.

Specifically, a commercial grade M2 n-type silicon wafer is used, and is polished, textured, and cleaned with an alkaline solution to form a silicon wafer substrate (light absorbing layer) with a textured structure, and then PECVD is used to form a tunneling layer on the silicon wafer substrate.

Silicon-based batteries can be heterojunction batteries, PERC (Passivated Emitter and Rear Cell) batteries, TOPCON (Tunnel Oxide Passivated Contact) batteries, etc.

In step 2, a first carrier transport layer conforming to the textured structure is formed on the surface of the tunneling layer facing away from the silicon wafer by vacuum evaporation.

In step 3, there are two methods for forming a two-dimensional three-dimensional bulk mixed perovskite absorption layer, wherein the first method is:

A mixed layer containing lead halide is formed by a dual-source co-evaporation method or a vapor deposition method; then a mixed solution containing an organic amine salt that can form a two-dimensional perovskite is spin-coated on the surface of the mixed layer. Because the mixed layer has formed a conformal framework with the velvet structure on the silicon-based battery, the two-dimensional perovskite seed crystals planted by spin-coating the mixed solution on the mixed layer also remain conformal with the velvet structure on the silicon-based battery. The organic amine salt in the mixed solution that can form a two-dimensional perovskite is at a low concentration (molar concentration of 0.05mM to 0.4mM). The solvent in the mixed solution that can react with the lead halide in the mixed layer to form a two-dimensional perovskite is a mixed solvent of a perovskite anti-solvent and IPA. The perovskite anti-solvent is selected as an anti-solvent with good perovskite film-forming quality as much as possible, so that the planted two-dimensional perovskite seed crystals can be kept embedded in the lead halide layer as much as possible; in the case of a two-dimensional perovskite layer attached, The perovskite precursor solution that can form a three-dimensional perovskite is spin-coated on the mixed layer of the mineral seed crystals. Because the mixed layer formed in the first two steps has maintained a conformal framework with the velvet structure of the silicon-based battery, and the perovskite precursor solution that can form a three-dimensional perovskite does not dissolve the two-dimensional perovskite seed crystals when it is spin-coated, the two-dimensional perovskite seed crystals are included in the three-dimensional perovskite film layer, and finally a two-dimensional three-dimensional bulk mixed perovskite absorption layer is formed.

The specific steps are as follows:

Step a1: forming a mixed layer containing lead halide on a surface of the first carrier transport layer facing away from the substrate;

Specifically, a mixed layer containing lead halide is formed on a surface of the first carrier transport layer that is away from the substrate by using a dual-source co-evaporation method or a vapor deposition method.

The thickness of the mixed layer is 200-500nm, for example, it can be 200nm, 210nm, 220nm, 230nm, 240nm, 250nm, 260nm, 270nm, 280nm, 290nm, 300nm, 310nm, 320nm, 330nm, 340nm, 350nm, 360nm, 370nm, 380nm, 390nm, 400nm, 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm, 490nm or 500nm.

In the mixed layer, the content of lead halide is 95%-99%, for example, it can be 95%, 95.1%, 95.2%, 95.3%, 95.4%, 95.5%, 95.6%, 95.7%, 95.8%, 95.9%, 96%, 96.1%, 96.2%, 96.3%, 96.4%, 96.5%, 96.6%, 96.7%, 96.8%, 96.9%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99. ... 6.8%, 96.9%, 97%, 97.1%, 97.2%, 97.3%, 97.4%, 97.5%, 97.6%, 97.7%, 97.8%, 97.9%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9% or 99%.

Step b1: forming a two-dimensional perovskite seed crystal on a surface of the mixed layer facing away from the first carrier transport layer;

Specifically, an organic amine salt is dissolved in a mixed solvent formed by a perovskite antisolvent and isopropanol to form a mixed solution 1, and the mixed solution 1 is spin-coated on the surface of the mixed layer away from the substrate. The mixed solution 1 reacts with the mixed layer for 5-30 seconds to generate a two-dimensional perovskite seed crystal. The two-dimensional perovskite and lead halide have different colors. The lead halide film is a light yellow transparent film, and the two-dimensional perovskite is a black, purple, reddish brown dot-shaped, strip-shaped, or sheet-shaped distributed film.

In the mixed solution 1, the molar concentration of the organic amine salt is 0.05mM to 0.7mM, preferably 0.4mM to 0.5mM, for example, it can be 0.05mM, 0.06mM, 0.07mM, 0.08mM, 0.09mM, 0.1mM, 0.11mM, 0.12mM, 0.13mM, 0.14mM, 0.15mM, 0.16mM, 0.17mM, 0.18mM, 0.19mM, 0.2mM, 0.21mM, 0.22mM, 0.23mM, 0.24mM, 0.25mM, 0.26mM, 0.27mM, 0.28mM, 0.29mM, 0.3mM, 0.31mM, 0.32mM, 0.33mM, 0.34mM, 0.35mM, 0.36mM, 0.37mM, 0.38mM, 0.39mM, 0.4mM, 0.41mM, 0.42mM, 0.43mM, 0.44mM, 0.45mM, 0.46mM, 0.47mM, 0.4 8mM, 0.49mM, 0.5mM, 0.51mM, 0.52mM, 0.53mM, 0.54mM, 0.55mM, 0.56mM, 0.57mM, 0.58mM, 0.59mM, 0.6mM, 0.61mM, 0.62mM, 0.63mM, 0.64mM, 0.65mM, 0.66mM, 0.67mM, 0.68mM, 0.69mM or 0.7mM.

The higher the molar concentration of the organic ammonium salt, the larger the size of the generated two-dimensional perovskite seed crystals and the greater the number of seed crystals. The greater the concentration of the organic ammonium salt, the larger the organic amine salt molecules that can react with the lead halide, so the more violent the reaction, the larger the generated two-dimensional perovskite seed crystals and the greater the number.

The organic amine salt is selected from one of benzyl ammonium hydrohalide, γ-fluorobenzyl ammonium hydrohalide, phenethyl ammonium hydrohalide, γ-fluorophenethyl ammonium hydrohalide, n-butylamine hydrohalide, isobutylamine hydrohalide, halobutylammonium hydrohalide, halopropylammonium hydrohalide, ionic liquid or 1-naphthylamine hydrohalide.

Benzyl ammonium hydrohalide is FBAX, and Y-fluorobenzylammonium hydrohalide is Y-FBAX, wherein X=I, Br, Cl; and Y=ortho-, para-, or meta-position fluorine substitution.

Phenethylammonium hydrohalide is PEAX, and Y-fluorophenethylammonium hydrohalide is Y-PEAX, wherein X=I, Br, Cl; and Y=ortho-, para-, or meta-fluorine substitution.

The n-butylamine hydrohalide is BAX, the isobutylamine hydrohalide is γ-BAX, and the halobutylammonium hydrohalide is YdBAX, wherein X=I, Br, Cl; and Y=I, Br, Cl, F.

The halopropylammonium hydrohalide is YdPAX, X = I, Br, Cl; Y = I, Br, Cl, F. The ionic liquid is ILs.

1-Naphthylamine hydrohalide is 1-NAX, wherein X=I, Br, Cl.

The volume ratio of the perovskite antisolvent to isopropanol is (1.5-9):1, for example, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4:1, 4.2:1, 4.3:1, 4.4:1, 4.5:1, 4.6:1, 4.7:1, 4.8: 1, 4.9:1, 5:1, 5.2:1, 5.3:1, 5.4:1, 5.5:1, 5.6:1, 5.7:1, 5.8:1, 5.9:1, 6:1, 6.2:1, 6.3:1, 6.4:1, 6.5:1, 6.6:1, 6.7:1, 6.8:1, 6.9:1, 7:1, 7.2:1, 7.3:1, 7.4:1, 7.5:1, 7.6:1, 7.7:1, 7.8:1, 7.9:1, 8:1, 8.2:1, 8.3:1, 8.4:1, 8.5:1, 8.6:1, 8.7:1, 8.8:1, 8.9:1, or 9:1.

Isopropyl alcohol (IPA) dissolves the organic components in the two-dimensional perovskite seed crystals, but does not dissolve the two-dimensional perovskite seed crystals and three-dimensional perovskites generated in the previous and next steps. The role of two-dimensional perovskite is that IPA will not dissolve perovskite, so it can accurately separate and determine that two-dimensional perovskite and three-dimensional perovskite are generated separately in a certain order, and it will not dissolve and destroy the two-dimensional perovskite generated in the first step. At the same time, because two-dimensional and three-dimensional perovskites are formed separately, the structure and composition of three-dimensional perovskite will not be affected by the first generated two-dimensional perovskite (the photovoltaic performance of three-dimensional perovskite is far better than that of two-dimensional perovskite, so the structure and composition of three-dimensional perovskite must be guaranteed to be independent. Two-dimensional perovskite induces the growth of three-dimensional perovskite in order to obtain better pure three-dimensional perovskite, rather than introducing two-dimensional perovskite into the composition and structure of three-dimensional perovskite).

The perovskite antisolvent is one or more of ether, chlorobenzene, ethyl acetate and benzamidine.

Step c1: spin-coating a three-dimensional perovskite precursor on the surface of the mixed layer having the two-dimensional perovskite seed crystal, and the three-dimensional perovskite precursor reacts with the mixed layer to obtain a two-dimensional three-dimensional bulk mixed perovskite absorption layer.

The three-dimensional perovskite precursor solution is one or a mixture of two or more of MAI, FAI, CsI, MABr, FABr, and CsBr.

The second method to form a 2D and 3D bulk hybrid perovskite absorber is:

A small amount of low-concentration organic amine salt and lead halide are used to form a two-dimensional perovskite precursor, and a mixed solvent of a perovskite antisolvent and DMF is added to the two-dimensional perovskite precursor to form a second mixed solution, and a two-dimensional perovskite seed crystal is planted on the surface of the first carrier transport layer away from the substrate by a one-step solution method such as spin coating, scraping, and spraying. The concentration of the two-dimensional perovskite precursor in the second mixed solution is low (molar concentration 0.05mM to 0.4mM), and the perovskite antisolvent causes the two-dimensional perovskite in the two-dimensional perovskite precursor to precipitate tiny seed crystals, so that the planted two-dimensional perovskite seed crystals are kept dispersed and attached to the surface of the first carrier transport layer as much as possible. On the first carrier transport layer with two-dimensional perovskite seed crystals attached to the surface, a dual-source co-evaporation method or a vapor deposition method is used to form a mixed layer containing lead halide covering the two-dimensional perovskite seed crystal, and the mixed layer forms a conformal frame with the velvet structure of the silicon-based battery, so that the two-dimensional perovskite seed crystal is wrapped in the mixed layer. A three-dimensional perovskite precursor solution that can form a three-dimensional perovskite is spin-coated on the mixed layer. Since the mixed layer formed in the first two steps has maintained a conformal framework with the velvet structure of the silicon-based battery, and the two-dimensional perovskite seed crystals are not dissolved when the perovskite precursor solution that forms the three-dimensional perovskite is spin-coated, the two-dimensional perovskite seed crystals are contained in the three-dimensional perovskite film layer, and finally a two-dimensional three-dimensional bulk mixed perovskite absorption layer is formed.

The specific steps are as follows:

Step a2: forming a two-dimensional perovskite seed crystal on a surface of the first carrier transport layer facing away from the substrate;

Specifically, an organic amine salt and a lead halide are mixed to form a two-dimensional perovskite precursor, and a mixed solvent formed by a perovskite antisolvent and DMF is added to the two-dimensional perovskite precursor to form a second mixed solution, and the second mixed solution is spin-coated on a surface of a side of the first carrier transport layer facing away from the substrate, thereby completing the reaction on the side surface of the first carrier transport layer within 5-30 seconds to form a two-dimensional perovskite seed crystal.

In the second mixed solution, the molar concentration of the two-dimensional perovskite precursor is 0.05mM to 0.4mM, for example, 0.05mM, 0.06mM, 0.07mM, 0.08mM, 0.09mM, 0.1mM, 0.11mM, 0.12mM, 0.13mM, 0.14mM, 0.15mM, 0.16mM, 0.17mM, 0.18mM, 0.19mM, 0.2mM, 0.21mM, 0.22mM, 0.23mM, 0.24mM, 0.25mM, 0.26mM, 0.27mM, 0.28mM, 0.29mM, 0.3mM, 0.31mM, 0.32mM, 0.33mM, 0.34mM, 0.35mM, 0.36mM, 0.37mM, 0.38mM, 0.39mM or 0.4mM.

The volume ratio of the perovskite antisolvent to DMF is (1.5-9):1, for example, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4:1, 4.2:1, 4.3:1, 4.4:1, 4.5:1, 4.6:1, 4.7:1, 4.8: 1, 4.9:1, 5:1, 5.2:1, 5.3:1, 5.4:1, 5.5:1, 5.6:1, 5.7:1, 5.8:1, 5.9:1, 6:1, 6.2:1, 6.3:1, 6.4:1, 6.5:1, 6.6:1, 6.7:1, 6.8:1, 6.9:1, 7:1, 7.2:1, 7.3:1, 7.4:1, 7.5:1, 7.6:1, 7.7:1, 7.8:1, 7.9:1, 8:1, 8.2:1, 8.3:1, 8.4:1, 8.5:1, 8.6:1, 8.7:1, 8.8:1, 8.9:1, or 9:1.

The perovskite antisolvent is one or more of tetrahydrofuran, acetonitrile, dimethoxyethanol, ethyl acetate, benzamidine and chlorobenzene.

The organic ammonium salt is selected from A ₂ BX ₄ (A may be MA ⁺ , FA ⁺ or Cs ⁺ , and B may be Sn ²⁺ or Pb ²⁺ ), benzyl ammonium hydrohalide, Y-fluorobenzyl ammonium hydrohalide, phenethyl ammonium hydrohalide, Y-fluorophenethyl ammonium hydrohalide, n-butylamine hydrohalide, isobutylamine hydrohalide, halobutylammonium hydrohalide, halopropylammonium hydrohalide, ionic liquid or 1-naphthylamine hydrohalide.

The halopropylammonium hydrohalide is YdPAX, X = I, Br, Cl; Y = I, Br, Cl, F. Ionic liquid The body is ILs.

1-Naphthylamine hydrohalide is 1-NAX, wherein X=I, Br, Cl.

In the present application, the amount of two-dimensional perovskite seed crystals formed can be controlled by controlling the amount of perovskite anti-solvent added to the two-dimensional perovskite precursor solution. The solubility of the two-dimensional perovskite precursor solution to perovskite is limited. Adding an anti-solvent here is equal to the two-dimensional perovskite precursor part of the solvent being extracted by the anti-solvent, so the concentration of the two-dimensional perovskite precursor gradually increases until the precipitation of perovskite micro-grains (seed crystals). The more anti-solvent is added, the more the number of perovskite seed crystals precipitated in the two-dimensional perovskite precursor is, and the larger the size. It is also possible to control the concentration of organic ammonium salts. The higher the concentration of organic ammonium salts, the larger the size of the two-dimensional perovskite seed crystals generated and the more the number of seed crystals. The larger the concentration of organic ammonium salts is, the larger the organic amine salt molecules that can react with lead halide are, so the more violent the reaction is, and the larger the two-dimensional perovskite seed crystals generated are, and the more the number is.

Step b2: forming a mixed layer containing lead halide on a surface of one side of the first carrier transport layer having the two-dimensional perovskite seed crystal;

Specifically, a dual-source co-evaporation method or a vapor deposition method is used to form a mixed layer covering the two-dimensional perovskite seed crystal on the surface of one side of the first carrier transport layer having the two-dimensional perovskite seed crystal.

Step c2: spin-coating a three-dimensional perovskite precursor solution on the surface of the mixed layer facing away from the first carrier transport layer, and the three-dimensional perovskite precursor solution reacts with the mixed layer to obtain a two-dimensional three-dimensional bulk mixed perovskite absorption layer.

In step four, a second carrier transport layer is formed by evaporation using a vacuum coating device on a surface of the two-dimensional and three-dimensional bulk mixed perovskite absorption layer that is away from the first carrier transport layer.

In the present application, the preparation method also includes the following steps:

Step 5: A buffer layer is formed by depositing the second carrier transport layer on the surface of the second carrier transport layer away from the two-dimensional and three-dimensional bulk mixed perovskite absorption layer using an atomic layer deposition device.

Step six: a transparent conductive layer is deposited on the surface of the buffer layer facing away from the second carrier transport layer.

Step 7: Using a mask method to evaporate and form a metal electrode on the surface of the transparent conductive layer on the side away from the buffer layer and on the surface of the light absorbing layer on the side away from the tunneling layer.

Step 8: Prepare an anti-reflection film on the front side (perovskite side) using electron beam evaporation to reduce light reflection on the cell surface, thereby obtaining a two-dimensional three-dimensional bulk hybrid perovskite solar cell.

In the present application, the two-dimensional three-dimensional bulk phase hybrid perovskite solar cell prepared by the method is the aforementioned two-dimensional three-dimensional bulk phase hybrid perovskite solar cell. For details, please refer to the description of the aforementioned two-dimensional three-dimensional bulk phase hybrid perovskite solar cell.

In the present application, since the three-dimensional perovskite grows on the surface of the two-dimensional perovskite seed crystal, the three-dimensional perovskite grains are induced to grow in a directional manner, and the grains grow very large, thereby improving the device Jsc. In the final two-dimensional three-dimensional bulk mixed perovskite absorption layer, the three-dimensional perovskite grows on the surface of the two-dimensional perovskite seed crystal, and finally the two-dimensional perovskite is squeezed at the three-dimensional perovskite grain boundary (here the two-dimensional perovskite seed crystal is not generated in situ at the three-dimensional perovskite grain boundary after the three-dimensional perovskite is generated), so a small part of the two-dimensional perovskite seed crystal is distributed at the three-dimensional perovskite grain boundary, and most of it is distributed on the surface of the three-dimensional perovskite film layer, so the two-dimensional perovskite seed crystal passivates the surface and grain boundary of the three-dimensional perovskite. Because the two-dimensional perovskite seed crystal and the three-dimensional perovskite have different components, the electronic energy levels are different. Therefore, the contact between the two-dimensional perovskite seed crystal and the three-dimensional perovskite aligns the energy band of the entire stacked device, improves the carrier lifetime of the device, and improves the FF and Voc of the device; inhibits ion migration, and inhibits the erosion and damage of the perovskite film layer by water and oxygen in the external environment; specifically, the hysteresis of the stacked device is reduced (the forward scan and reverse scan IV curves have a high degree of overlap), and at the same time the working stability of the device is greatly improved, and the performance decays slowly after long-term operation in the external environment.

Example

The implementation methods used in the following embodiments are all conventional methods unless otherwise specified.

Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

Example 1

The preparation method of the two-dimensional three-dimensional bulk hybrid perovskite solar cell of this embodiment comprises the following steps:

Step 1: providing a silicon-based battery with a velvet structure;

Specifically, a 180μm commercial grade M2 n-type silicon wafer with a resistivity of 5Ω.cm was polished, textured and cleaned with an alkaline solution to form a silicon wafer substrate with a textured structure. A PECVD (Plasma Enhanced Chemical Vapor Deposition) process was used to prepare a tunneling layer on the light incident side of the battery. The tunneling layer can be formed by depositing a uc-Si-p+ layer and a uc-Si-n+ layer separately using PECVD to form a tunneling junction with a thickness of 30nm.

Step 2: forming a first carrier transport layer on the surface of the silicon-based battery;

Specifically, by vacuum evaporation (the rate of evaporation is ) On the tunneling layer, Sprio-TTB is used to form a first carrier transport layer (hole transport layer) conformal to the velvet structure, with a thickness of 10 nm.

Step 3: forming a two-dimensional and three-dimensional mixed perovskite absorption layer conformal to the suede structure on the surface of the first carrier transport layer facing away from the tunneling layer;

Specifically, the evaporation rate of cesium bromide is first adjusted to The evaporation rate of lead iodide (PbI ₂ ) is A mixed layer of lead iodide and cesium bromide with a thickness of 400 nm was deposited; a mixed solution 1 (the concentration of PEAI in the mixed solution 1 is 0.4 mM) formed by 50 μL of PEAI and a solvent (the solvent is a mixture of IPA and ether, wherein the volume ratio of ether to IPA is 9:1) was dropped on the mixed layer, and immediately spin-coated to obtain PEA ₂ PbI ₄ , and annealed at 150° C. for 10 min to form a two-dimensional perovskite seed crystal on the mixed layer; 90 μL of a FAI and FABr solution with a molar concentration of 3:1 was dropped on the mixed layer with the two-dimensional perovskite seed crystal, immediately spin-coated, and annealed at 150° C. for 30 min to obtain a two-dimensional three-dimensional bulk mixed perovskite absorption layer with a thickness of 500 nm, the content of the two-dimensional perovskite seed crystal in the two-dimensional three-dimensional bulk mixed perovskite absorption layer was 1%, and the particle size distribution of the two-dimensional perovskite seed crystal was 20-200 nm.

Step 4: forming a second carrier transport layer on a surface of the two-dimensional and three-dimensional bulk mixed perovskite absorption layer facing away from the first carrier transport layer.

Specifically, the surface of the two-dimensional three-dimensional bulk mixed perovskite absorption layer facing away from the first carrier transport layer is evaporated by a vacuum coating device at an evaporation rate of A C60 layer (second carrier transport layer) was formed to a thickness of 10 nm.

Step 5: A SnO ₂ layer (buffer layer) with a thickness of 10 nm is deposited on the surface of the second carrier transport layer away from the two-dimensional and three-dimensional bulk mixed perovskite absorption layer using an atomic layer deposition device.

Step 6: Deposit a 110 nm thick ITO film (transparent conductive layer) on the surface of the buffer layer facing away from the second carrier transport layer using magnetron sputtering technology.

Step 7: A silver grid line electrode is formed by evaporation using a mask method on the surface of the transparent conductive layer facing away from the buffer layer and on the surface of the light absorbing layer facing away from the tunneling layer. The thickness of the silver grid line electrode is 200 nm.

Step 8: Prepare a 120 nm _MgF2 anti-reflection film on the front side (perovskite side) by electron beam evaporation to obtain a two-dimensional three-dimensional bulk hybrid perovskite solar cell, the performance of which is shown in Table 1 and Figures 2-4.

Example 2

The two-dimensional three-dimensional bulk phase hybrid perovskite solar cell of this embodiment is different from that of Example 1 in that the preparation method of the two-dimensional three-dimensional bulk phase hybrid perovskite absorption layer in step three is different, as follows:

PEAI and PbI ₂ were mixed to form PEA ₂ PbI ₄ , and then 70 μL of the mixed solution II formed by the mixture of tetrahydrofuran, DMF and PEA ₂ PbI ₄ (the molar concentration of PEA ₂ PbI ₄ in the mixed solution II was 0.2 mM, and the volume ratio of tetrahydrofuran to DMF was 8.5:1.5) was dropped on the surface of the tunneling layer opposite to the first carrier transport layer, and immediately spin-coated and annealed at 150°C for 10 min to obtain the PEA ₂ PbI ₄ two-dimensional perovskite seed crystal. On the surface of one side of the first carrier transport layer with the PEA ₂ PbI ₄ two-dimensional perovskite seed crystal attached, a mixed layer containing lead halide was prepared by dual-source co-evaporation. First, the evaporation rate of cesium bromide was adjusted. The evaporation rate of lead iodide (PbI ₂ ) is A 400nm mixed layer of lead iodide and cesium bromide is deposited, and the mixed layer wraps _the _PEA2PbI4 two-dimensional perovskite seed crystals therein; 90μL of a FAI and FABr solution with a molar concentration of 3:1 is dropped on the mixed layer, immediately spin-coated, and annealed at 150°C for 30min to obtain a two-dimensional three-dimensional bulk mixed perovskite absorption layer with a thickness of 500nm. The content of the two-dimensional perovskite seed crystals in the two-dimensional three-dimensional bulk mixed perovskite absorption layer is 2%, and the particle size distribution of the two-dimensional perovskite seed crystals is 100-200nm.

The performance of two-dimensional and three-dimensional bulk hybrid perovskite solar cells is shown in Table 1.

The difference between the solar cells of Examples 3 to 8 and the solar cells of Example 2 is that the particle size distribution of the two-dimensional perovskite seed crystals is different. The particle size of the two-dimensional perovskite seed crystals is controlled by controlling the volume ratio of the perovskite antisolvent to DMF in the second mixed solution.

The performance of the solar cell is shown in Table 1.

The difference between the solar cells of Examples 9 to 15 and the solar cell of Example 1 is that the molar concentration of the organic amine salt in the mixed solution 1 is different.

The performance of the solar cell is shown in Table 1.

Comparative Example 1

The difference between the solar cell in Comparative Example 1 and the solar cell in Example 1 lies in step three. In step three of Comparative Example 1, a pure three-dimensional perovskite absorption layer is formed. The thickness of the three-dimensional perovskite absorption layer is 500 nm. The performance of the cell is shown in Table 1 and Figures 2-4.

Comparative Example 2

The difference between Comparative Example 2 and Comparative Example 1 is that a two-dimensional perovskite absorption layer is deposited between the three-dimensional perovskite absorption layer and the first carrier transport layer, and the thickness of the three-dimensional perovskite absorption layer is 400nm. The thickness of the two-dimensional perovskite absorption layer is 100nm. The battery performance is shown in Table 1.

Comparative Example 3

The difference between Comparative Example 3 and Comparative Example 1 is that a two-dimensional perovskite absorption layer is deposited between the three-dimensional perovskite absorption layer and the first carrier transport layer and between the three-dimensional perovskite absorption layer and the second carrier transport layer, and the thickness of the three-dimensional perovskite absorption layer is 300nm, and the thickness of the two-dimensional perovskite absorption layer is 100nm. The battery performance is shown in Table 1.

Table 1 shows the performance parameters of various embodiments and comparative examples.

Summary: It can be seen from the above table that as the size of the two-dimensional perovskite seed crystal increases, the performance of the solar cell prepared therefrom is normally distributed, first gradually becoming better and then worse. The hysteresis of Example 3 and Example 4 is relatively small, which may be because the size of the two-dimensional perovskite seed crystal is too small to agglomerate and increase the size, thereby reducing the hysteresis. In addition, the two-dimensional perovskite seed crystal plays an important role in inducing the growth of three-dimensional perovskite, which significantly improves Jsc. At the same time, the two-dimensional perovskite seed crystal is distributed on the grain boundary and surface of the three-dimensional perovskite, which inhibits the recombination of carriers at the grain boundary of the three-dimensional perovskite, greatly improving Voc and FF. In addition, the two-dimensional perovskite hinders the erosion of the perovskite grain boundary by water and oxygen in the external environment, greatly improving the working stability of the entire device.

In traditional perovskite cells, the perovskite layer usually uses a three-dimensional perovskite, and the three-dimensional perovskite is easily decomposed by the influence of moisture and oxygen in the air, resulting in poor stability of the solar cell. The perovskite cell is prepared into a two-dimensional/three-dimensional perovskite structure, the two-dimensional perovskite contains an organic amine hydrophobic end, and the two-dimensional perovskite is arranged along the interface direction parallel to the three-dimensional perovskite, which can effectively organize the penetration and attack of water molecules and improve the stability of the device. In addition, the hydrophobic end of the two-dimensional perovskite can effectively improve the stability of the device, but too many two-dimensional organic amine cations will lead to poor conductivity, and it is difficult for electrons to be transmitted inside the two-dimensional/three-dimensional perovskite, resulting in low device performance. In the present application, part of the two-dimensional perovskite is induced to be arranged along the interface perpendicular to the three-dimensional perovskite layer 202 and the two-dimensional perovskite layer 208, so as to improve the carrier transmission ability in the two-dimensional/three-dimensional perovskite.

The general structure of a standard 3D perovskite is ABX ₃ , with six halide anions (X sites; e.g., I ^- , Br ^{- ,} and Cl ^- ) forming a BX ₆ octahedral framework with divalent metal cations (B sites; e.g., Sn ²⁺ and Pb ²⁺ ). Twelve monovalent cations (A sites; e.g., MA ⁺ , FA ⁺ , and Cs ⁺ ) occupy the centers of four BX ₆ octahedra. 2D perovskites are often described by the formula (A') _m (A) _n-1 B _n X _3n+1 , where a divalent (m = 1) or monovalent (m = 2) cation forms a bilayer or monolayer of connected inorganic (A) _n-1 B _n X _3n+1 sheets, where n represents the thickness of the metal halide layer, which can be controlled by optimizing the precursor composition. In general, the organic A-site cations can be arbitrarily long, allowing the use of large, high-aspect-ratio cations (e.g., aliphatic or aromatic cations). The geometric structure of the two-dimensional octahedral arrangement usually contains a BX ₄ ^2- inorganic unit. In addition, the negative charge of a negative ion needs a positive charge to balance (for example, A ₂ 'BX ₄ , when n = 2, A' is a monovalent cation). It is worth noting that n = ∞ corresponds to a three-dimensional perovskite, while n = 1 represents a pure two-dimensional perovskite, and 1 < n ≤ 5 is usually called a quasi-two-dimensional perovskite. More importantly, even at high n values (such as n = 30-60), a mixture of three-dimensional perovskite and low-n phase (such as n ≤ 3) can be formed, which is called It is a quasi-three-dimensional perovskite. As n increases, the difference in thermodynamic stability of the high-n structure becomes smaller, making it difficult to prepare a pure high-n phase structure. Therefore, the n value of this perovskite is usually described based on the precursor composition.

As shown in FIG. 7 , the present application provides a solar cell, including a perovskite composite layer, wherein the perovskite composite layer includes a two-dimensional perovskite layer 208 and a three-dimensional perovskite layer 202 that are stacked;

At least part of the two-dimensional perovskite in the two-dimensional perovskite layer 208 is arranged along the interface perpendicular to the three-dimensional perovskite layer 202 and the two-dimensional perovskite layer 208, and the part of the two-dimensional perovskite is the first two-dimensional perovskite 2082. With such a design, since the part of the two-dimensional perovskite is arranged along the interface perpendicular to the three-dimensional perovskite layer 202 and the two-dimensional perovskite layer 208, the electron transmission between the two-dimensional perovskite layer 208 and the three-dimensional perovskite layer 202 can be promoted, thereby improving the efficiency of the solar cell.

As shown in Fig. 8, in the two-dimensional perovskite layer 208, at least part of the two-dimensional perovskite is arranged along the interface parallel to the three-dimensional perovskite layer 202 and the two-dimensional perovskite layer 208, and the part of the two-dimensional perovskite is the second two-dimensional perovskite 2081. With such a design, since the two-dimensional perovskite is arranged along the interface parallel to the three-dimensional perovskite layer 202 and the two-dimensional perovskite layer 208, it is possible to effectively prevent water penetration and improve the stability of the solar cell.

In the present application, in the two-dimensional perovskite layer 208 , the content of the first two-dimensional perovskite 2082 gradually decreases from a side surface close to the three-dimensional perovskite layer 202 to a side surface far from the three-dimensional perovskite layer 202 .

In the two-dimensional perovskite layer 208, the content of the second two-dimensional perovskite 2081 gradually increases from the surface of one side close to the three-dimensional perovskite layer 202 to the surface of one side far away from the three-dimensional perovskite layer 202. The first two-dimensional perovskite close to the three-dimensional side can promote the electron transport inside the perovskite, and the second two-dimensional perovskite far away from the three-dimensional perovskite can prevent water molecules from penetrating into the three-dimensional perovskite on the film surface, thereby improving the stability of the device.

In the present application, in the two-dimensional perovskite layer 208 , the ratio of the content of the first two-dimensional perovskite 2082 to the content of the second two-dimensional perovskite is (1-4):1, preferably 1.5:1.

Specifically, the ratio of the content of the first two-dimensional perovskite 2082 to the content of the second two-dimensional perovskite can be 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1 or 4:1.

In the present application, the solar cell further includes a substrate 105 , and the substrate 105 has a smooth surface or a velvet structure 1011 .

The substrate 105 may be a first transparent conductive layer or a bottom cell.

Specifically, when the substrate 105 is the first transparent conductive layer, the first transparent conductive layer has a smooth surface, and the solar cell is a single-layer solar cell. The solar cell includes a first transparent conductive layer, a first carrier transport layer 201, a perovskite composite layer, a second carrier transport layer 204, and a second transparent conductive layer 209 stacked in sequence, an anti-reflection layer 207 is arranged on the second transparent conductive layer 209, a second metal electrode 1032 is arranged on the surface of the side of the anti-reflection layer away from the second transparent conductive layer 209, the second metal electrode 1032 penetrates the anti-reflection layer 207 and contacts the second transparent conductive layer 209, and a first metal electrode 1031 is arranged on the surface of the side of the first transparent conductive layer away from the first carrier transport layer 201.

The first transparent conductive layer and the second transparent conductive layer 209 can both be ITO layers, FTO layers, IZO layers, IWO layers, AZO layers or ZTO layers, and have a thickness of 10 to 300 nm, for example, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, 290 nm or 300 nm.

The first carrier transport layer 201 can be a hole transport layer or an electron transport layer, and the conductivity types of the first carrier transport layer 201 and the second carrier transport layer 204 are opposite. When the first carrier transport layer 201 is a hole transport layer, it can be a molybdenum oxide layer, a [bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) layer, a copper iodide layer or a Spiro-OMeTAD (2,2',7,7'-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene Chinese name is 2,2',7,7'-tetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene) layer, a PEDOT layer, a PEDOT:PSS layer, a P3HT layer, a P3OHT layer, a P3ODDT layer, a NiOx layer or a CuSCN layer. The second carrier transport layer 204 is an electron transport layer, which can be a titanium oxide layer, a tin oxide layer, a C60 layer or a C60-PCBM layer, a [60]PCBM ([6,6]-phenyl-C ₆₁ butyric acid methyl ester, Chinese name is [6,6]-phenyl-C ₆₁ -butyric acid isomethyl ester) layer, a [70]PCBM ([6,6]-Phenyl-C ₇₁ -butyric acid methyl ester, Chinese name is [6,6]-phenyl-C ₇₁ -butyric acid isomethyl ester) layer, a bis[60]PCB (Bis(1-[3-(methoxycarbonyl)propyl]-1-phenyl)-[6,6]C ₆₂ ) layer, [60]ICBA (1',1",4',4"-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2",3"][5,6]fullerene-C60) layer, etc., including but not limited to these, as long as the functions in this application can be achieved.

When the first carrier transport layer 201 is an electron transport layer, it can be a titanium oxide layer, a tin oxide layer, a C60 layer or a C60-PCBM layer, [60]PCBM ([6,6]-phenyl-C ₆₁ butyric acid meth yl ester, Chinese name is [6,6]-phenyl-C ₆₁ -butyric acid isomethyl ester) layer, [70]PCBM ([6,6]-Phenyl-C ₇₁ -butyric acid methyl ester, Chinese name is [6,6]-phenyl-C ₇₁ -butyric acid isomethyl ester) layer, bis[60]PCB (Bis(1-[3-(methoxycarbonyl)propyl]-1-phenyl)-[6,6]C ₆₂ ) layer, [60]ICBA(1',1",4',4"-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2",3"][5,6]fullerene-C60) layer, etc. The second carrier transport layer 204 is a hole transport layer, which can be a molybdenum oxide layer, a [bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) layer, a copper iodide layer or a Spiro-OMeTAD (2,2',7,7'-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene Chinese name is 2,2',7,7'-tetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene) layer, a PEDOT layer, a PEDOT:PSS layer, a P3HT layer, a P3OHT layer, a P3ODDT layer, a NiOx layer or a CuSCN layer. Including but not limited to this, as long as the functions in the present application can be achieved. The thickness of the first carrier transport layer 201 and the second carrier transport layer 204 can be 1-500nm, for example, 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 20nm, 30nm, 40nm, 45nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 400nm, 450nm, 460nm, 470nm, 480nm, 490nm or 500nm.

The band gap of the perovskite composite layer is 1.65-1.69 ev, for example, it can be 1.65 ev, 1.66 ev, 1.67 ev, 1.68 ev or 1.69 ev.

The band gap is determined by PL testing, which measures the position of the emission peak of the perovskite composite layer. When the test results show that the peak position shifts to the left, it means that the band gap has increased.

The thickness of the perovskite composite layer is 350-500 nm, for example, 350 nm, 360 nm, 370 nm, 380 nm, 390 nm, 400 nm, 410 nm, 420 nm, 430 nm, 440 nm, 450 nm, 460 nm, 470 nm, 480 nm, 490 nm or 500 nm.

The three-dimensional perovskite layer 202 is a MAPbI _3- layer, a FAPbI _3- layer or a (Cs _0.15 FA _0.85 )Pb(I _0.7 Br _0.3 ) _3- layer, and its thickness is 400-800nm. For example, it can be 400nm, 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm, 490nm, 500nm, 510nm, 520nm, 530nm, 540nm, 550nm, 560nm, 570nm, 580nm, 590nm, 600nm, 610nm, 620nm, 630nm, 640nm, 650nm, 660nm, 670nm, 680nm, 690nm, 700nm, 710nm, 720nm, 730nm, 740nm, 750nm, 760nm, 770nm, 780nm, 790nm or 800nm.

The two-dimensional perovskite layer 208 is PEA ₂ MA _n-1 Pb _n I _3n+1 , where n≥1, and has a thickness of 30-80 nm, for example, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm or 80 nm.

The first metal electrode 1031 and the second metal electrode 1032 can be made of one or more metal materials such as Ag, Au, Cu, Al, Ni, C materials, and polymer conductive materials. The thickness of the first metal electrode 1031 and the second metal electrode 1032 is 50nm-50μm, for example, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, 210nm, 220nm, 230nm, 240nm, 250nm , 260nm, 270nm, 280nm, 290nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm, 850nm, 900nm, 950nm, 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm or 50μm.

The anti-reflection layer 207 may be made of at least one of _MgF2 , _SiNx , _Al2O3 _, _SiOx , _SiCx , etc., and has a thickness of 70-200 nm, for example, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm or 200 nm. In the present application, the anti-reflection layer 207 may not be present, and may be specifically provided according to actual needs.

Specifically, when the substrate 105 is a bottom cell, such as a silicon cell, a perovskite cell, a CIGS cell or a CZTS cell, the solar cell is a stacked solar cell. The solar cell includes a bottom cell, a tunneling layer 102, and a top cell stacked in sequence, the top cell includes a first carrier transport layer 201, a perovskite composite layer, a second carrier transport layer 204 and a second transparent conductive layer 209 stacked in sequence, an anti-reflection layer 207 is arranged on the second transparent conductive layer 209, and a second metal electrode 1032 is arranged on the surface of the side of the anti-reflection layer away from the second transparent conductive layer 209, and the second metal electrode 1032 penetrates the anti-reflection layer 207 and contacts the second transparent conductive layer 209.

The tunneling layer 102 may be a transparent conductive layer or a tunneling junction, etc., and its thickness is 10 to 500 nm, for example, it may be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, 290 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm.

As shown in FIG. 5 , when the substrate 105 (bottom cell) has a textured structure 1011 , both the three-dimensional perovskite layer 202 and the two-dimensional perovskite layer 208 are conformal to the substrate 105 .

In the present application, conformal means having the same shape, that is, in the present application, the three-dimensional perovskite layer 202 and the two-dimensional perovskite layer 208 also have a textured structure 1011 .

The basic shape of the velvet structure 1011 is selected from one or more of a column, a cone, a table, an arc groove or an arc protrusion, such as a positive or negative triangular prism, a quadrangular prism, a hexagonal prism, a cylindrical, a cone, a triangular pyramid, a quadrangular pyramid, a truncated table, a triangular prism, a quadrangular table, a semicircular groove or a semicircular protrusion.

The velvet structure 1011 may be composed of one or more of a plurality of columnar, conical, terraced, arc-shaped grooves or arc-shaped protrusions.

The first two-dimensional perovskite 2082 is perpendicular to the interface of the three-dimensional perovskite layer 202 stacked with it and close to the two-dimensional perovskite layer 208; the second two-dimensional perovskite is parallel to the interface of the three-dimensional perovskite layer 202 stacked with it and close to the two-dimensional perovskite layer 208. Since the interface of the three-dimensional perovskite layer 202 close to the two-dimensional perovskite layer 208 is a velvet structure 1011, and the velvet structure 1011 has multiple surfaces in different directions, the two-dimensional perovskite layer 208 also has multiple first two-dimensional perovskites 2082 and second two-dimensional perovskites in different directions.

As shown in Figure 6, when the substrate 105 (bottom cell) does not have a velvet surface and the surface of the substrate 105 is a smooth horizontal surface, the first two-dimensional perovskite 2082 is perpendicular to the interface of the three-dimensional perovskite layer 202 stacked therewith close to the two-dimensional perovskite layer 208; in the two-dimensional perovskite layer 208, the first two-dimensional perovskite 2082 is arranged in a direction perpendicular to the horizontal plane.

The second two-dimensional perovskite is parallel to the interface of the three-dimensional perovskite layer 202 stacked therewith and close to the two-dimensional perovskite layer 208; in the two-dimensional perovskite layer 208, the second two-dimensional perovskites are arranged in the horizontal direction.

In the present application, the first carrier transport layer 201, the second carrier transport layer 204, the second transparent conductive layer 209, the first metal electrode 1031 and the second metal electrode 1032 in the stacked solar cell can all refer to the description in the aforementioned single-layer solar cell.

Preparing a three-dimensional perovskite layer 202;

Preparing a two-dimensional perovskite layer 208 on the surface of the three-dimensional perovskite layer 202;

At least a portion of the two-dimensional perovskite in the two-dimensional perovskite layer 208 is perpendicular to the three-dimensional perovskite layer 202. and the interface arrangement of the two-dimensional perovskite layer 208 , where this portion of two-dimensional perovskite is the first two-dimensional perovskite 2082 .

Specifically, the method for preparing a solar cell comprises the following steps:

Step 1: providing a substrate 105;

Specifically, when the solar cell is a single-layer solar cell, the substrate 105 is the first transparent conductive layer. When the solar cell is a stacked solar cell, the substrate 105 may be a bottom cell, which may be a silicon cell, a perovskite cell, a CIGS cell or a CZTS cell.

Furthermore, the tunneling layer 102 is prepared on the light incident side of the bottom cell by using PVD, ALD, spin coating, spray coating, or slit coating processes.

Step 2: forming a first carrier transport layer 201 on one side surface of the substrate 105 .

Specifically, the first carrier transport layer 201 is formed by vacuum evaporation, atomic deposition, or PVD sputtering.

Step 3: forming a perovskite composite layer on the surface of the first carrier transport layer 201 facing away from the substrate 105;

Specifically, the three-dimensional perovskite layer 202 is prepared on the surface of the first carrier transport layer 201 facing away from the substrate 105 by using an anti-solvent method such as spin coating. The preparation process is as follows:

First, a perovskite precursor solution is prepared. The composition of the perovskite precursor solution is based on the ABX ₃ structure of the precursor solution. The A position uses a ternary mixed cation, which is Cs, FA, and MA; the B position is a Pb metal ion; the X position uses a mixed anion type ratio of I and Br. Then, the perovskite precursor solution is evenly coated on the surface of the first carrier transport layer 201 facing away from the substrate 105 by spin coating, and then annealed to form a three-dimensional perovskite layer 202.

Then, an organic amine salt solution is prepared and spin-coated on the surface of the three-dimensional perovskite layer 202 away from the first carrier transport layer 201, and the organic amine salt solution reacts with the residual lead halide in the three-dimensional perovskite layer 202 to generate a two-dimensional perovskite layer 208;

In the two-dimensional perovskite layer 208 , at least part of the two-dimensional perovskite is arranged along an interface perpendicular to the three-dimensional perovskite layer 202 and the two-dimensional perovskite layer 208 , and the part of the two-dimensional perovskite is the first two-dimensional perovskite 2082 .

Since the two-dimensional perovskite has a preferred orientation, the two-dimensional perovskite prepared at room temperature is arranged in a direction parallel to the interface of the three-dimensional perovskite layer 202 stacked therewith. The two-dimensional perovskite with a hydrophobic end can effectively prevent water molecules from penetrating into the three-dimensional perovskite. However, since the organic amine cation is non-conductive, it is difficult for electrons to be transmitted between the two-dimensional perovskite layer 208 and the three-dimensional perovskite layer 202. Excessive organic amine cations will lead to poor device performance. By adopting hot coating, additives and solvent engineering, the two-dimensional perovskite is induced to be arranged in a direction perpendicular to the interface between the three-dimensional perovskite layer 202 and the two-dimensional perovskite layer 208. The organic amine salt solution and the surface of the three-dimensional perovskite layer are heated respectively, and then the heated organic amine salt solution is spin-coated on the surface of the heated three-dimensional perovskite layer. After the spin coating is completed, annealing is performed to form a two-dimensional perovskite layer.

Specifically, the hot coating method is: heat the organic amine salt solution and the surface of the three-dimensional perovskite layer 202 respectively, and then spin-coat the heated organic amine salt solution on the surface of the heated three-dimensional perovskite layer 202, until the spin coating is completed, annealing to form a two-dimensional perovskite layer 208, wherein at least part of the two-dimensional perovskite in the two-dimensional perovskite layer 208 is arranged along an interface perpendicular to the three-dimensional perovskite layer 202 and the two-dimensional perovskite layer 208, and this part of the two-dimensional perovskite is a first two-dimensional perovskite 2082.

The heating temperature of the three-dimensional perovskite layer 202 is 120-150°C, for example, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C.

The heating temperature of the organic amine salt solution is 60-90°C, for example, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or 90°C.

Specifically, the organic amine salt solution is formed by dissolving the organic amine salt in solvent one.

Solvent one is isopropanol or ethanol.

The concentration of the organic amine salt in the organic amine salt solution is 0.2-0.5 mol/l, preferably 0.3 mol/l, for example, 0.2 mol/l, 0.3 mol/l, 0.4 mol/l or 0.5 mol/l.

The organic amine salt is selected from RP type organic amine salt, DJ type organic amine salt or ACI type organic amine salt. The RP type organic amine salt can be phenylethylamine hydrohalide (PEAX is phenylethylammonium salt, for example, PEAI, PEABr or PEACl) or n-butylamine hydrohalide. PEAX can be PEAI, PEABr or PEACl, preferably PEAI. The n-butylamine hydrohalide can be n-butylamine hydroiodide, n-butylamine hydrobromide or n-butylamine hydrochloride, preferably n-butylamine hydroiodide.

The DJ type organic amine salt may be 3-(aminomethyl)piperidinium (3AMP) and 4-(aminomethyl)piperidinium (4AMP).

The ACI-type organic amine salt may be a guanidine salt (GUA).

The non-polar solvent is one of CB (CB chlorobenzene), isopropanol, ethanol or toluene.

Specifically, solvent engineering means that when the organic amine salt and solvent one remain unchanged, adding solvent two can also induce the growth direction of two-dimensional perovskite.

Solvent 2 is one of chlorobenzene, ethyl acetate, toluene, N-methylpyrrolidone or γ-butyrolactone;

The volume ratio of solvent one to solvent two is (2-9):1, for example, it can be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1 or 9:1.

In the organic amine salt solution formed by the organic amine salt, solvent one and solvent two, the concentration of the organic amine salt is 0.2-0.5 mol/l, preferably 0.3 mol/l, for example, 0.2 mol/l, 0.3 mol/l, 0.4 mol/l or 0.5 mol/l.

Specifically, the method of adding the additive is as follows: before spin coating, the additive is added into the organic amine salt solution.

The additive is one of ammonium chloride, ammonium thiocyanate, methylammonium chloride and ammonium thiocyanate, preferably ammonium chloride.

In the organic amine salt solution formed by the additive, the organic amine salt and the solvent, the concentration of the additive is 2-15 mg/mL, preferably 3 mg/mL-4 mg/mL, for example, it can be 2 mg/mL, 3 mg/mL, 4 mg/mL, 5 mg/mL, 6 mg/mL, 7 mg/mL, 8 mg/mL, 9 mg/mL, 10 mg/mL, 11 mg/mL, 12 mg/mL, 13 mg/mL, 14 mg/mL or 15 mg/mL.

Step 4: forming a second carrier transport layer 204 on a surface of the perovskite composite layer that is away from the first carrier transport layer 201 .

Specifically, the second carrier transport layer 204 is formed by vacuum evaporation, atomic deposition, or PVD sputtering.

Step 5: Form a second transparent conductive layer 209 on the surface of the second carrier transport layer 204 that is away from the perovskite composite layer. The preparation method is a conventional method and is not specifically limited in this application.

Step 6: forming an anti-reflection layer 207 on the surface of the second transparent conductive layer 209 facing away from the second carrier transport layer 204. The preparation method is a conventional method and is not specifically limited in this application. In this application, step 6 can also be omitted.

Step 7: Forming a first metal electrode 1031 and a second metal electrode 1032 .

A second metal electrode 1032 is formed on a surface of the anti-reflection layer 207 that is away from the second transparent conductive layer 209 and penetrates through the anti-reflection layer 207 and contacts the second transparent conductive layer 209 .

When step six is not performed, a second metal electrode 1032 is formed on a surface of the second transparent conductive layer 209 which is away from the second carrier transport layer 2047 .

A first metal electrode 1031 is formed on a surface of the substrate 105 that is away from the first carrier transport layer 201 .

Formation. The preparation method of the first metal electrode 1031 and the second metal electrode 1032 is a conventional method and is not specifically limited in this application.

The solar cell prepared by the preparation method of the present application is the aforementioned solar cell, and the specific contents can refer to the aforementioned description of the solar cell.

Example

Example 16

This embodiment is a laminated perovskite cell, the lower cell has a velvet surface, and the preparation method thereof includes the following steps:

Step 1: Use a commercial grade _M2 n-silicon wafer with a thickness of 180μm and a resistivity of 5Ω.cm, and polish, texture and clean it with an alkaline solution to form a silicon wafer substrate with a pyramid texture surface. Then, deposit a 10nm intrinsic amorphous silicon passivation layer on the front and back sides in PECVD to passivate the dangling bonds on the surface of the crystalline silicon. Further, use a hydrogen-diluted phosphine and silane mixed gas to deposit a 10nm thick n-type amorphous silicon emitter, and use a hydrogen-diluted diborane and silane mixed gas to deposit a 15nm thick p-type amorphous silicon back field.

A tunneling layer 102 is prepared by a PECVD process on the surface of the n-type amorphous silicon emitter facing away from the intrinsic amorphous silicon passivation layer. Specifically, a silane with a hydrogen dilution ratio (hydrogen/silane flow ratio is 250) and phosphine mixed gas is used to prepare 5nm heavily doped n-type microcrystalline silicon, and a silane with a hydrogen dilution ratio (hydrogen/silane flow ratio is 250) and diborane mixed gas is used to prepare 10nm heavily doped p-type microcrystalline silicon to form the tunneling layer 102.

Step 2: Prepare the first carrier transport layer 201 on the tunneling layer 102 by evaporation at a rate of Thickness: 10nm, material: Sprio-TTB.

Step three: forming a perovskite composite layer on the surface of the first carrier transport layer 201 which is away from the tunneling layer 102 .

Specifically, 100 μl of perovskite precursor solution is taken, the precursor solution is an ABX ₃ structure, a ternary mixed cation is selected at the A position, namely Cs, FA, MA; the B position is a Pb metal ion; the X position uses an anion type of I and Br mixture, wherein the Cs content is 5%, and the ratio of I to Br is between 7:3 and 8:2. The solvent is a mixed solvent of DMF and DMSO with a concentration of 1.5M. The prepared precursor solution has a band gap of about 1.65 ev. The taken out perovskite precursor solution is dripped on the surface of the side of the first carrier transport layer 201 away from the tunneling layer 102, and the surface is spin-coated at a speed of 1000 rpm and then 4000 rpm for 10 s and 30 s respectively. 5 s before the end of spin coating, 200 μl of anti-solvent is taken and quickly dripped on the device surface (within 1 s), and the anti-solvent is chlorobenzene. After the spin coating is completed, the obtained device is annealed on a hot stage at 100°C for 10 min to form a three-dimensional perovskite layer 202 with a thickness of 400 nm.

Then, take 50 μl of organic amine salt solution, the organic amine salt is phenylethylamine hydroiodide, non-polar The solvent is isopropanol, and the concentration of the organic amine salt in the organic amine salt solution is 0.3 M. The taken-out organic amine salt solution is dripped onto the surface of the three-dimensional perovskite layer 202 on the side away from the first carrier transport layer 201. The heating temperature of the three-dimensional perovskite layer 202 is 120°C, and the heating temperature of the organic amine salt solution is 90°C. The three-dimensional perovskite layer 202 is spin-coated at a speed of 3000 revolutions for 30 seconds. After the spin coating is completed, the obtained device is annealed on a hot stage at 120°C for 10 minutes to complete the preparation of the two-dimensional perovskite layer 208, which has a thickness of 30 nm.

Step 4: Place the structure obtained in step 3 in a vacuum coating device. 10 nm C60 is evaporated at an evaporation rate of 1.1 Å, and a 10 nm SnO ₂ layer is further prepared by an atomic layer deposition device. The C60 and SnO ₂ layers constitute the second carrier transport layer 204 .

Step 5: A 110 nm ITO film is deposited on both surfaces of the structure obtained in step 4 to form a transparent conductive layer.

Step 6: A 200 nm silver grid electrode is deposited on the surfaces of the two transparent conductive layers by using a mask method, thereby obtaining a solar cell. The parameters of the solar cell are shown in Table 2.

Embodiment 17

The difference between the stacked solar cell in Example 17 and the stacked solar cell in Example 16 is only in step three. In step three of this embodiment, when preparing the two-dimensional perovskite layer 208, there is no need to heat the organic amine salt solution and the three-dimensional perovskite layer 202.

The parameters of the solar cell are shown in Table 2.

Embodiment 18

The difference between the stacked solar cell in Example 18 and the stacked solar cell in Example 2 is only in step three. In step three of this embodiment, the additive ammonium chloride is added to the organic amine salt solution. The concentration of the organic amine salt in the organic amine salt solution is 0.3M, and the concentration of ammonium chloride is 1 mg/ml.

The parameters of the solar cell are shown in Table 2.

Embodiment 19

The difference between the stacked solar cell in Example 19 and the stacked solar cell in Example 17 is only the type of the non-polar solvent in step 3. In this embodiment, the non-polar solvent in step 3 is chlorobenzene.

The parameters of the solar cell are shown in Table 2.

Embodiment 20

The difference between the stacked solar cell in Example 20 and the stacked solar cell in Example 1 is that the bottom cell in this Example 5 does not have the velvet structure 1011 .

The parameters of the solar cell are shown in Table 2.

The difference between the stacked solar cells of Examples 21 to 25 and the stacked solar cells of Example 18 is only the concentration of ammonium chloride, which are 2 mg/ml, 3 mg/ml, 4 mg/ml, 5 mg/ml and 8 mg/ml respectively.

The parameters of the solar cell are shown in Table 2.

The difference between the stacked solar cells of Examples 26 to 28 and the stacked solar cell of Example 16 is only the concentration of the organic amine salt, which are 0.2M, 0.5M, and 0.7M, respectively.

The parameters of the solar cell are shown in Table 2.

The difference between the tandem solar cells of Examples 29-30 and Comparative Example 6 and the tandem solar cell of Example 16 is only the temperature during thermal coating.

The parameters of the solar cell are shown in Table 2.

The difference between the solar cell in Example 31 and the stacked solar cell in Example 16 is that the solar cell in this example is a single-layer cell.

The parameters of the solar cell are shown in Table 2.

Comparative Example 4

The difference between the stacked solar cell in Comparative Example 4 and the stacked solar cell in Example 17 is that in Comparative Example 4, there is no two-dimensional perovskite layer 208 but only a three-dimensional perovskite layer 202 .

The parameters of the solar cell are shown in Table 2.

Comparative Example 5

The difference between the laminated solar cell of Comparative Example 5 and the laminated solar cell of Example 17 is that in the two-dimensional perovskite layer 208 of Comparative Example 5, the two-dimensional perovskite is all parallel to the three-dimensional perovskite. Interface arrangement of the titanium ore layer 202 and the two-dimensional perovskite layer 208 .

The parameters of the solar cell are shown in Table 2.

Table 2 shows the performance parameters of each embodiment and comparative example.

Note: The ratio of the content of the first two-dimensional perovskite to the content of the second two-dimensional perovskite is A1:A2, the heating temperature of the thermally coated three-dimensional perovskite layer is T1, and the heating temperature of the thermally coated organic amine salt is T2.

Summary: From the above table, we can see that the solar cells prepared by traditional methods only contain three-dimensional perovskite layers. Battery, three-dimensional perovskite layer is susceptible to moisture and oxygen in the air, and is very easy to decompose, resulting in poor stability of the stacked device. The present application prepares a two-dimensional perovskite layer on the three-dimensional perovskite layer. Since the two-dimensional perovskite contains an organic amine hydrophobic end, the second two-dimensional perovskite in the two-dimensional perovskite layer is arranged in a direction parallel to the interface of the three-dimensional perovskite layer in contact with it, which can effectively organize water molecule penetration and attack, improve device stability, and the first two-dimensional perovskite induced by methods such as hot coating, additives, and solvent engineering is arranged along the interface perpendicular to the three-dimensional perovskite layer in contact with it, which can promote electron transmission between the two-dimensional perovskite layer and the three-dimensional perovskite layer, thereby improving device efficiency.

As shown in Figures 9 and 10, the present application provides a solar cell having a two-dimensional three-dimensional bulk mixed perovskite absorption layer 203, wherein the two-dimensional three-dimensional bulk mixed perovskite absorption layer 203 contains two-dimensional perovskite and three-dimensional perovskite, and the two-dimensional perovskite is uniformly dispersed in the three-dimensional perovskite.

Specifically, the two-dimensional perovskite grows along the thickness direction of the two-dimensional three-dimensional bulk mixed perovskite absorption layer, so that the two-dimensional perovskite can better transport electrons.

The two-dimensional three-dimensional bulk mixed perovskite absorption layer 203 in the solar cell has two-dimensional perovskite uniformly dispersed in the three-dimensional perovskite. The two-dimensional perovskite can passivate defects at the grain boundaries of the three-dimensional perovskite, thereby improving the stability and performance of the solar cell.

In the present application, the mass ratio of two-dimensional perovskite to three-dimensional perovskite is 1:(2-9), preferably 1:6.

Specifically, the mass ratio of two-dimensional perovskite to three-dimensional perovskite can be 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, or 1:9.

Such a design is adopted in the present application. The inventors found that three-dimensional perovskite absorbs sunlight as the main component of the two-dimensional three-dimensional bulk phase mixed perovskite absorption layer 203. The two-dimensional perovskite is mixed with the three-dimensional perovskite. The two-dimensional perovskite can not only better passivate the defects at the three-dimensional perovskite grain boundaries, but also better prevent water molecules from penetrating the two-dimensional three-dimensional bulk phase mixed perovskite absorption layer 203, thereby achieving the purpose of improving stability.

In the present application, the grain size S2 of the two-dimensional perovskite is distributed in the range of 80-150 nm, accounting for more than 90%. Preferably, the grain size S2 of the two-dimensional perovskite is distributed in the range of 80 nm-110 nm, accounting for more than 90%.

The grain size refers to the largest lateral dimension of a plane.

The grain size was measured by scanning electron microscopy.

Specifically, the grain size S2 of the two-dimensional perovskite accounting for more than 90% can be 80nm, 90nm, 100nm, 11nm, 120nm, 130nm, 140nm, and 150nm.

In the present application, the grain size S1 of the three-dimensional perovskite is distributed in the range of 500-800 nm, accounting for more than 90%.

Specifically, the grain size S1 of the three-dimensional perovskite accounting for more than 90% can be 500nm, 510nm, 520nm, 530nm, 540nm, 550nm, 560nm, 570nm, 580nm, 590nm, 600nm, 600nm, 610nm, 620nm, 630nm, 640nm, 650nm, 660nm, 670nm, 680nm, 690nm, 700nm, 710nm, 720nm, 730nm, 740nm, 750nm, 760nm, 770nm, 780nm, 790nm or 800nm.

Specifically, the applicant has found that the larger the three-dimensional perovskite grain size, the fewer grain boundaries, the fewer internal defects of the perovskite, the better the crystallinity of the film, and the higher the device efficiency.

Specifically, by testing the film surface using SEM, the particle size of two-dimensional perovskite and three-dimensional perovskite can be determined.

In the present application, the thickness of the two-dimensional three-dimensional bulk mixed perovskite absorption layer 203 is 300-600 nm, preferably 590 nm, for example, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 590 nm or 600 nm.

In the present application, the band gap of the two-dimensional and three-dimensional bulk mixed perovskite absorption layer 203 is 1.5-1.7ev, for example, it can be 1.5eV, 1.51eV, 1.52eV, 1.53eV, 1.54eV, 1.55eV, 1.56eV, 1.57eV, 1.58eV, 1.59eV, 1.6eV, 1.61eV, 1.62eV, 1.63eV, 1.64eV, 1.65eV, 1.66eV, 1.67eV, 1.68eV, 1.69eV or 1.7eV.

Specifically, when the solar cell is a stacked cell, the band gap of the two-dimensional three-dimensional bulk mixed perovskite absorption layer 203 is 1.65-1.69 eV.

Specifically, the band gap of the two-dimensional three-dimensional bulk mixed perovskite absorption layer 203 can be determined by PL testing.

Specifically, two-dimensional perovskites contain large-sized organic amine cations, and the band gap can be adjusted by regulating the content of two-dimensional organic amine cations. The general structure of standard three-dimensional perovskites is ABX ₃ , with six halide anions (X sites; for example, ^I- , ^Br- and ^Cl- ) and divalent metal cations (B sites; such as Sn ²⁺ and Pb ²⁺ ) forming a BX ₆ octahedral framework. Twelve monovalent cations (A sites; for example, MA ⁺ , FA ⁺ and Cs ⁺ ) occupy the centers of four BX ₆ octahedra. Two-dimensional perovskites are usually described by the formula (A') _m (A) _n-1 B _n X _3n+1 , where a divalent (m＝1) or monovalent (m＝2) cation forms a double layer or Monolayers of connected inorganic (A) _n-1 B _n X _3n+1 sheets, where n represents the thickness of the metal halide layer, can be controlled by optimizing the precursor composition. In general, the organic A-site cation can be arbitrarily long, which allows the use of large, high-aspect-ratio cations (such as aliphatic or aromatic cations). The 2D octahedral geometry usually contains a BX ₄ ^2- inorganic unit, and the negative charge of the other anion needs to be balanced by a positive charge (e.g., A ₂ 'BX ₄ , when n=2, A' is a monovalent cation). It is worth noting that n=∞ corresponds to a 3D perovskite, while n=1 represents a pure 2D perovskite, and 1<n≤5 is generally referred to as quasi-2D. More importantly, even at high n values (such as n=30-60), a mixture of 3D perovskites and low-n phases (such as n≤3) can be formed, which is referred to in the art as quasi-3D perovskites. As n increases, the difference in thermodynamic stability of the high-n structure becomes smaller, making it difficult to prepare pure high-n phase structures. Therefore, the n value of such perovskites is usually described based on the precursor composition.

In the present application, the substrate is a silicon-based cell or a glass substrate.

When the base is a glass substrate, the solar cell is a single-layer solar cell, which includes a first metal electrode layer 1, a first transparent conductive layer 2, a first carrier transport layer 201, a two-dimensional three-dimensional bulk mixed perovskite absorption layer 203, a second carrier transport layer, a buffer layer, a second transparent conductive layer 209 and a second metal electrode layer 13 stacked in sequence.

The first carrier transport layer 201 can be a hole transport layer or an electron transport layer, and the first carrier transport layer 201 and the second carrier transport layer have opposite conductivity types. When the first carrier transport layer 201 is a hole transport layer, it can be a cuprous oxide layer, a molybdenum oxide layer, a [bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) layer, a copper iodide layer or a Spiro-OMeTAD (2,2',7,7'-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene Chinese name is 2,2',7,7'-tetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene) layer, a PEDOT layer, a PEDOT:PSS layer, a P3HT layer, a P3OHT layer, a P3ODDT layer, a NiOx layer or a CuSCN layer. The second carrier transport layer is an electron transport layer, which can be a titanium oxide layer, a tin oxide layer, a C60 layer or a C60-PCBM layer, a [60]PCBM ([6,6]-phenyl-C61 butyric acid methyl ester, Chinese name is [6,6]-phenyl-C61-butyric acid isomethyl ester) layer, a [70]PCBM ([6,6]-Phenyl-C71-butyric acid methyl ester, Chinese name is [6,6]-phenyl-C71-butyric acid isomethyl ester) layer. ) layer, bis[60]PCBM (Bis(1-[3-(methoxycarbonyl)propyl]-1-phenyl)-[6,6]C62) layer, [60]ICBA(1',1",4',4"-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2",3"][5,6]fullerene-C60) layer, etc., including but not limited to these, as long as the functions in the present application can be achieved.

When the first carrier transport layer 201 is an electron transport layer, it can be a titanium oxide layer, a tin oxide layer, a C60 layer or a C60-PCBM layer, [60]PCBM ([6,6]-phenyl-C61 butyric acid methyl ester, Chinese name is [6,6]-phenyl-C61-butyric acid isomethyl ester) layer, [70]PCBM ([6,6]-Phenyl-C71-butyric acid methyl ester, Chinese name is [6,6]-phenyl-C71-butyric acid isomethyl ester) layer, bis[60]PCBM (Bis(1-[3-(methoxycarbonyl)propyl]-1-phenyl)-[6,6]C62) layer, [60]ICBA(1',1",4',4"-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2",3"][5,6]fullerene-C60) layer, etc. The second carrier transport layer is a hole transport layer, which can be a cuprous oxide layer, a molybdenum oxide layer, a [bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) layer, a copper iodide layer or a Spiro-OMeTAD (2,2',7,7'-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene Chinese name 2,2',7,7'-tetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene) layer, a PEDOT layer, a PEDOT:PSS layer, a P3HT layer, a P3OHT layer, a P3ODDT layer, a NiOx layer or a CuSCN layer. Including but not limited to this, as long as the functions in the present application can be achieved.

The thickness of the first carrier transport layer 201 is 10-15 nm, for example, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm or 15 nm.

The buffer layer is used for the longitudinal transport of carriers and protects the perovskite absorption layer from being damaged by sputtering in the subsequent PVD process. The buffer layer may be a _SnO2 layer or a _TiO2 layer with a thickness of 5-30 nm, for example, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, 28 nm, 29 nm or 30 nm.

The buffer layer and the second carrier transport layer may be collectively referred to as a second carrier transport layer.

The first transparent conductive layer 2 and the second transparent conductive layer 209 can both be transparent conductive films, specifically fluorine-doped tin oxide (FTO), indium tin oxide (ITO) or aluminum-doped zinc oxide (AZO) and the like; the thickness of the transparent conductive layer is 1-20nm, for example, it can be 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm, 15nm, 16nm, 17nm, 18nm, 19nm or 20nm.

The first metal electrode layer 1 and the second metal electrode layer 13 can be made of one or more of metal materials such as Ag, Au, Cu, Al, Ni, C materials, and polymer conductive materials.

When the substrate is a silicon-based cell, and the solar cell is a stacked solar cell, as shown in FIG10 , the stacked solar cell includes a silicon-based cell and a perovskite cell, the silicon-based cell and the perovskite cell are stacked together through a composite layer 8, and the perovskite cell includes a first carrier transport layer from bottom to top 201, a two-dimensional three-dimensional bulk phase mixed perovskite absorption layer 203 and a second carrier transport layer, a buffer layer, a transparent conductive layer and an anti-reflection layer. The surface of the first carrier transport layer 201 facing away from the two-dimensional three-dimensional bulk phase mixed perovskite absorption layer 203 is stacked together with the surface of the composite layer 8 facing away from the silicon-based battery. The solar cell also includes a first metal electrode and a second metal electrode. The first metal electrode is arranged on the surface of the silicon-based battery facing away from the composite layer 8, and the second metal electrode penetrating the anti-reflection layer and connected to the transparent conductive layer is arranged on the surface of the anti-reflection layer facing away from the transparent conductive layer.

The anti-reflection layer may be MgF ₂ , LiF, SiO ₂ , etc., and may have a thickness of 50-300 nm, for example, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm or 300 nm.

The first carrier transport layer 201, the two-dimensional three-dimensional bulk phase mixed perovskite absorption layer 203 and the second carrier transport layer, the buffer layer, the transparent conductive layer, the first metal electrode and the second metal electrode in the stacked solar cell can all refer to the description of the first carrier transport layer 201, the two-dimensional three-dimensional bulk phase mixed perovskite absorption layer 203 and the second carrier transport layer, the buffer layer, the first transparent conductive layer 2, the first metal electrode and the second metal electrode in the single-layer solar cell.

The silicon-based cell may be one of a silicon heterojunction solar cell, a TOPCon solar cell, a PERC solar cell or a tunneling oxide passivation contact cell, including but not limited to these.

Step 1: preparing a substrate;

Step 2: forming a first carrier transport layer 201 on the surface of the substrate;

Step 3: forming a two-dimensional three-dimensional bulk mixed perovskite absorption layer 203 on the surface of the first carrier transport layer 201 facing away from the substrate;

Step 4: forming a second carrier transport layer on a surface of the two-dimensional and three-dimensional bulk mixed perovskite absorption layer 203 that is away from the first carrier transport layer 201;

The two-dimensional three-dimensional bulk mixed perovskite absorption layer 203 contains two-dimensional perovskite and three-dimensional perovskite, and the two-dimensional perovskite is uniformly dispersed in the three-dimensional perovskite.

In step 1, when the solar cell is a stacked solar cell and the silicon cell is a silicon heterojunction cell, the following steps are included:

Step 1a: The silicon wafer is subjected to polishing, texturing, coating and cleaning in sequence to form a silicon substrate 5 .

Specifically, a commercial grade M2 n-type silicon wafer is used, and is polished, textured, and cleaned with an alkaline solution to form an n-type silicon substrate 5 having a textured structure.

Step 1b: Prepare passivation layers on both sides of the silicon substrate 5, namely the first passivation layer 4 and the second passivation layer 5. Second passivation layer 6.

Specifically, the intrinsic amorphous silicon passivation layers are sequentially deposited on the front and back surfaces of the n-type silicon substrate 5 in a plasma enhanced chemical vapor deposition (PECVD) device, that is, the first passivation layer 4 is a first intrinsic amorphous silicon passivation layer, and the second passivation layer 6 is a second intrinsic amorphous silicon passivation layer.

Step 1c: forming a second doping layer 7 on a surface of the second passivation layer 6 facing away from the silicon substrate 5 .

Specifically, a mixed gas of phosphine and silane diluted with hydrogen is used to deposit an n-type amorphous silicon emitter on the surface of the second passivation layer 6 facing away from the silicon substrate 5 .

Step 1d: forming a first doping layer 3 on a surface of the first passivation layer 4 facing away from the silicon substrate 5 .

Specifically, a p-type amorphous silicon back field is deposited on the surface of the first passivation layer facing away from the silicon substrate 5 by using a mixture of diborane and silane diluted with hydrogen.

Step 1e: forming a composite layer 8 on the surface of the second doping layer 7 which is away from the second passivation layer 6 .

Specifically, a mixed gas of silane and phosphine diluted with hydrogen is used to prepare heavily doped n-type microcrystalline silicon, and a mixed gas of silane and diborane diluted with hydrogen is used to prepare heavily doped p-type microcrystalline silicon to form a tunneling composite layer.

When the solar cell is a single-layer solar cell, the substrate is the first transparent conductive layer 2 .

In step 2, a first carrier transport layer 201 is formed on a surface of the composite layer that is away from the second doping layer 7/first transparent conductive layer 2 by vacuum evaporation.

In step 3, the two-dimensional three-dimensional bulk mixed perovskite absorption layer 203 is formed by the following method:

Step 3a: preparing a three-dimensional perovskite precursor solution;

Specifically, a three-dimensional perovskite precursor is dissolved in a solvent to form a three-dimensional perovskite precursor solution, and the three-dimensional perovskite precursor solution is a ternary perovskite precursor solution.

The three-dimensional perovskite precursor has an ABX ₃ structure. The A position uses a ternary mixed cation, namely Cs, FA, and MA; the B position uses a Pb metal ion; the X position uses a mixed anion type of I and Br, and the ratio of I to Br is between 7:3 and 8:2. The solvent is a mixed solvent of DMF and DMSO.

Step 3b: Add organic amine and hydrohalic acid to the three-dimensional perovskite precursor solution, and mix them evenly to obtain a mixed solution.

The volume ratio of the mixed solution of organic amine and hydrohalic acid to the perovskite precursor solution is 1:(45-65), preferably 1:(48-52), for example, it can be 1:48, 1:49, 1:50, 1:51, 1:52, 1:53, 1:54, 1:55, 1:56, 1:57, 1:58, 1:59, 1:60, 1:61, 1:62, 1:63, 1:64, or 1:60.

The volume ratio of the hydrohalic acid to the organic amine is (0.7-1.2):1, preferably (0.9-1.1):1, for example, it can be 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1 or 1.2:1.

The hydrohalic acid is selected from one of hydroiodic acid, hydrobromic acid or hydrochloric acid, preferably hydroiodic acid.

The organic amine is selected from one of benzylamine, γ-fluorobenzylamine, phenethylamine, γ-fluorophenethylamine, n-butylamine, isobutylamine, halobutylamine, halopropylamine or 1-naphthylamine.

Benzylamine is FBA, and Y-fluorobenzylamine is Y-FBA.

Phenethylamine is PEA and Y-fluoroaniline is Y-PEA.

n-Butylamine is BA, isobutylamine is γ-BA, and halobutylamine is YdBA.

The halopropylamine is YdPA.

Step 3c: applying the mixed solution to the surface of the first carrier transport layer 201 facing away from the substrate, thereby forming a two-dimensional three-dimensional bulk mixed perovskite absorption layer 203 .

Furthermore, the mixed solution is spin-coated on the surface of the first carrier transport layer 201 facing away from the substrate, and an anti-solvent is added to the surface coated with the mixed solution before the spin coating is completed, thereby forming a two-dimensional and three-dimensional bulk mixed perovskite absorption layer 203.

The anti-solvent is chlorobenzene, anisole or ethyl acetate.

In step 4: a second carrier transport layer is formed by evaporation on a surface of the two-dimensional and three-dimensional bulk mixed perovskite absorption layer 203 which is away from the first carrier transport layer 201 by vacuum coating equipment.

Step 5: A buffer layer is formed by depositing the second carrier transport layer on the surface of the side away from the two-dimensional and three-dimensional bulk mixed perovskite absorption layer 203 using an atomic layer deposition device.

Step six: a transparent conductive layer/second transparent conductive layer 209 is deposited on the surface of the buffer layer facing away from the second carrier transport layer.

Step 7: A second metal electrode is formed by mask evaporation on the surface of the transparent conductive layer/second transparent conductive layer 209 facing away from the buffer layer. At the same time, a first metal electrode is formed by mask evaporation on the surface of the first transparent conductive layer 2 facing away from the first doping layer 3 .

Step eight is optional.

In the prior art, two-dimensional and three-dimensional perovskite cells are formed on the three-dimensional perovskite layer by organic amine cation salts, and a small part of the two-dimensional perovskite is distributed on the grain boundary of the three-dimensional phase to play a passivation role. However, the two-dimensional perovskite prepared by organic amine cation salts is compatible with the two-dimensional It is easy to be distributed on the surface of the three-dimensional perovskite layer, resulting in difficulty in electron transmission, unremarkable passivation, weak water vapor barrier effect, and low overall device performance. In addition, organic amine cationic salts need to be organically synthesized using organic amine solutions, and the synthesis steps are relatively difficult, and the purity of the synthesized ammonium salt is not high, and it is necessary to purify it multiple times, the process is long, and it takes a long time, the preparation process is complicated, and the yield is low. The present application prepares a two-dimensional three-dimensional body mixed perovskite structure by adding a mixed solution of hydrohalic acid and organic amine to the precursor solution of the three-dimensional perovskite, in which the two-dimensional perovskite is uniformly dispersed in the three-dimensional perovskite, and the two-dimensional perovskite can better passivate the defects at the three-dimensional perovskite grain boundary with such a design, and obtain enhanced water vapor barrier ability and electron transmission efficiency, thereby improving the stability of solar cells and battery performance. At the same time, the two-dimensional perovskite has the effect of adjusting the band gap, and the band gap of the stacked battery can be adjusted by the amount of the two-dimensional perovskite incorporated (as shown in Figure 11), so as to achieve the purpose of top and bottom battery current matching.

Example

The experimental methods used in the following examples are all conventional methods unless otherwise specified.

Embodiment 32

The two-dimensional and three-dimensional bulk hybrid perovskite solar cell of this embodiment is a single-layer solar cell, and its preparation method includes the following steps:

Step 1: Prepare the substrate

FTO glass is used as the first transparent conductive layer, and its thickness is 10 nm.

Step 2: Prepare the first carrier transport layer

The hole transport layer was prepared on one side of the first transparent conductive layer by evaporation at a rate of The material of the hole transport layer is Spiro-TTB, and its thickness is 10 nm.

Step 3: Preparation of 2D and 3D bulk mixed perovskite absorber layer

Take 100 microliters of perovskite precursor solution. The precursor is ABX ₃ structure. The A position uses ternary mixed cations, namely Cs, FA, and MA; the B position is Pb metal ion; the X position uses a mixed anion type of I and Br, where the Cs content is 5%, the ratio of I to Br is 7:3, and the solvent is a mixed solvent of DMF and DMSO with a concentration of 1.5M (the concentration here is the concentration of Pb ²⁺ ). Subsequently, add the HI:PEA (V:V=1:1) mixed solution to the perovskite precursor solution. Precursor solution: HI+PEA (V: V＝50:1), prepare a mixed precursor solution with a band gap of about 1.65ev, drop the mixed precursor solution on the surface of the hole transport layer away from the first transparent conductive layer, spin coat at a speed of 1000 rpm and then 4000 rpm for 10s and 30s respectively, 5s before the end of spin coating, take 200 microliters of anti-solvent and quickly drop it on the device surface (within 1s), the anti-solvent is chlorobenzene, after the spin coating, anneal the obtained device on a hot stage at 100°C for 10min to complete the preparation of the two-dimensional three-dimensional bulk mixed perovskite absorption layer, the thickness of the two-dimensional three-dimensional bulk mixed perovskite absorption layer is 600nm.

Step 4: Preparation of the second carrier transport layer and buffer layer

First adopt A 10 nm C60 layer (i.e., the second carrier transport layer) is deposited on the surface of the two-dimensional three-dimensional bulk phase mixed perovskite absorption layer away from the first carrier transport layer at an evaporation rate of 100 nm, and then an atomic layer deposition device is used to prepare a ₁₀ nm SnO2 layer (i.e., a buffer layer) on the surface of the second carrier transport layer away from the two-dimensional three-dimensional bulk phase mixed perovskite absorption layer.

Step 5: Preparation of the second transparent conductive layer

A 110 nm ITO film was prepared by deposition on the surface of the buffer layer away from the second carrier transport layer using magnetron sputtering.

Step 6: Prepare metal electrodes

A 200nm silver grid electrode was evaporated on the first transparent conductive layer and the second transparent conductive layer by a mask method, so as to obtain a solar cell. The parameters of the solar cell are shown in Table 3.

Embodiment 33

The solar cell of this embodiment is a stacked solar cell, which differs from Embodiment 32 only in step 1, which is as follows:

Step 1a: A commercial grade M2 n-type silicon wafer with a thickness of 180 μm and a resistivity of 5 Ω·cm is used, and polished, textured, and cleaned with an alkaline solution to form an n-type silicon substrate with a textured structure.

Step 1b: In a plasma enhanced chemical vapor deposition (PECVD) device, 10 nm intrinsic amorphous silicon passivation layers are deposited on the front and back surfaces of the n-type silicon substrate respectively, that is, the first passivation layer is the first intrinsic amorphous silicon passivation layer, and the second passivation layer is the second intrinsic amorphous silicon passivation layer.

Step 1c: using a mixture of phosphine and silane diluted with hydrogen to deposit an n-type amorphous silicon emitter with a thickness of 10 nm on the surface of the second passivation layer facing away from the silicon substrate.

Step 1d: using a mixture of diborane and silane diluted with hydrogen to deposit a p-type amorphous silicon back field with a thickness of 15 nm on the surface of the first passivation layer facing away from the silicon substrate.

Step 1e: Using a mixture of hydrogen-diluted silane (hydrogen/silane flow ratio of 250) and phosphine A heavily doped n-type microcrystalline silicon with a thickness of 5 nm was prepared, and a heavily doped p-type microcrystalline silicon with a thickness of 10 nm was prepared using a mixture of hydrogen-diluted silane (hydrogen/silane flow ratio of 250) and diborane to form a tunneling composite layer.

The parameters of the solar cell of this embodiment are shown in Table 3.

The difference between Example 34 to Example 37 and Example 33 lies in the volume ratio of the organic amine and hydrohalic acid to the perovskite precursor solution.

The parameters of the solar cell of this embodiment are shown in Table 3.

The difference between Example 38 to Example 41 and Example 33 lies in the volume ratio of the hydrohalic acid to the organic amine.

The parameters of the solar cell of this embodiment are shown in Table 3.

The difference between Example 42 and Example 43 and Example 33 lies in the type of hydrogen halide.

The parameters of the solar cell of this embodiment are shown in Table 3.

The difference between Example 44 to Example 46 and Example 33 lies in the type of organic amine.

The parameters of the solar cell of this embodiment are shown in Table 3.

Comparative Example 7

The difference between Comparative Example 7 and Example 33 is that no organic amine and hydrohalic acid are added in step three.

The parameters of the solar cell of this embodiment are shown in Table 3.

Comparative Example 8

The difference between Comparative Example 8 and Example 33 is that in step 3, no organic amine and hydrohalic acid are added, but organic amine salt PEAI is directly added in an amount of 3 mg/mL.

The parameters of the solar cell of this embodiment are shown in Table 3.

Table 3 shows the parameters of each embodiment and comparative example.

Summary: As can be seen from Table 3, the solar cell of the present application prepares a two-dimensional three-dimensional bulk phase mixed perovskite absorption layer by adding hydrohalic acid and organic amine to the precursor solution of three-dimensional perovskite. In the two-dimensional three-dimensional bulk phase mixed perovskite absorption layer, the two-dimensional perovskite is uniformly dispersed in the three-dimensional perovskite layer, which better passivates the defects at the grain boundaries of the three-dimensional perovskite, enhances the water vapor barrier capacity and the electron transmission efficiency, thereby improving the stability and battery performance of the solar cell, and the battery efficiency can reach 28.16%.

Although the embodiments of the present application are described above, the present application is not limited to the above specific embodiments and application fields, and the above specific embodiments are merely illustrative and instructive, rather than restrictive. A person of ordinary skill in the art can make many forms under the guidance of this specification and without departing from the scope of protection of the claims of the present application, all of which belong to the protection of the present application.

Claims

A two-dimensional three-dimensional bulk phase mixed perovskite solar cell, comprising a substrate, on one side of which a first carrier transport layer, a two-dimensional three-dimensional bulk phase mixed perovskite absorption layer and a second carrier transport layer are sequentially stacked;

The two-dimensional and three-dimensional bulk mixed perovskite absorption layer contains two-dimensional perovskite seed crystals and three-dimensional perovskite, and the two-dimensional perovskite seed crystals are located at the grain boundaries of the three-dimensional perovskite and the surface of the three-dimensional perovskite.
The solar cell according to claim 1, wherein the particle size distribution of the two-dimensional perovskite seed crystals is 20nm-200nm.
The solar cell according to claim 1, wherein in the two-dimensional three-dimensional bulk mixed perovskite absorption layer, the content of the two-dimensional perovskite seed crystal is 0.1%-5%;

The content of the three-dimensional perovskite is 95%-99.9%; or

The particle size distribution of the two-dimensional perovskite seed crystals is 140-170 nm, accounting for more than 90%.
The solar cell according to claim 1, wherein the substrate has a velvet structure, and the first carrier transport layer, the two-dimensional three-dimensional bulk mixed perovskite absorption layer and the second carrier transport layer are all conformal to the velvet structure of the substrate.
The solar cell according to claim 4, wherein the velvet structure is randomly or regularly distributed on at least one surface of the substrate;

The basic shape of the velvet structure is selected from one or more of a columnar shape, a cone shape, a table shape, an arc-shaped groove or an arc-shaped protrusion.
The solar cell according to any one of claims 1 to 5, wherein the thickness of the two-dimensional three-dimensional bulk mixed perovskite absorption layer is 350-700 nm.
The solar cell according to any one of claims 1 to 5, wherein the substrate is a silicon-based cell.
A method for preparing a two-dimensional three-dimensional bulk phase hybrid perovskite solar cell, comprising the following steps:

providing a substrate;

forming a first carrier transport layer on the surface of the substrate;

Forming a two-dimensional and three-dimensional bulk mixed perovskite absorption layer on a surface of the first carrier transport layer facing away from the substrate;

Forming a second carrier transport layer on a surface of the two-dimensional and three-dimensional bulk mixed perovskite absorption layer that is away from the first carrier transport layer;

The two-dimensional and three-dimensional bulk mixed perovskite absorption layer contains two-dimensional perovskite seed crystals and three-dimensional perovskite, and the two-dimensional perovskite seed crystals are located at the grain boundaries of the three-dimensional perovskite.
The method according to claim 8, wherein the two-dimensional three-dimensional bulk mixed perovskite absorption layer is formed by the following method:

forming a mixed layer containing lead halide on a surface of the first carrier transport layer facing away from the substrate;

forming a two-dimensional perovskite seed crystal on a surface of the mixed layer facing away from the first carrier transport layer;

A three-dimensional perovskite precursor solution is spin-coated on the surface of the mixed layer having the two-dimensional perovskite seed crystal, and the three-dimensional perovskite precursor solution reacts with the mixed layer to obtain a two-dimensional three-dimensional bulk mixed perovskite absorption layer.
The method according to claim 9, wherein a mixed layer containing lead halide is formed on a surface of the first carrier transport layer facing away from the substrate by a dual-source co-evaporation method or a vapor deposition method.
The method according to claim 9, wherein the thickness of the mixed layer is 200-500 nm,

In the mixed layer, the content of the lead halide is 95%-99%.
The method according to claim 9, wherein an organic amine salt is added to a mixed solvent formed by a perovskite antisolvent and isopropanol to form a mixed solution 1, and the mixed solution 1 is spin-coated on the mixed layer On a surface on a side away from the substrate, the mixed solution reacts with the mixed layer to form a two-dimensional perovskite seed crystal.
The method according to claim 12, wherein in the mixed solution 1, the molar concentration of the organic amine salt is 0.05mM to 0.7mM, or

The volume ratio of the perovskite antisolvent to isopropanol is (1.5-9):1.
The method according to claim 12, wherein the perovskite antisolvent is at least one of ether, chlorobenzene, ethyl acetate and benzamidine.
The method according to claim 8, wherein the two-dimensional three-dimensional bulk mixed perovskite absorption layer is formed by the following method:

forming a two-dimensional perovskite seed crystal on a surface of the first carrier transport layer facing away from the substrate;

forming a mixed layer containing lead halide on a surface of the first carrier transport layer having the two-dimensional perovskite seed crystal;

A three-dimensional perovskite precursor solution is spin-coated on the surface of the mixed layer on the side away from the first carrier transport layer, and the three-dimensional perovskite precursor solution reacts with the mixed layer to obtain a two-dimensional and three-dimensional bulk mixed perovskite absorption layer.
The method according to claim 15, wherein the two-dimensional perovskite seed crystal is prepared by the following steps:

An organic amine salt is mixed with a lead halide to form a two-dimensional perovskite precursor, and then a mixed solvent formed by a perovskite antisolvent and DMF is added to the two-dimensional perovskite precursor to form a second mixed solution, and the second mixed solution is spin-coated on a side surface of the first carrier transport layer facing away from the substrate, thereby forming a two-dimensional perovskite seed crystal on the side surface of the first carrier transport layer.
The method according to claim 16, wherein in the mixed solution 2, the molar concentration of the two-dimensional perovskite precursor is 0.05 mM to 0.4 mM, or

The volume ratio of the perovskite anti-solvent to DMF is (1.5-9):1.
The method according to claim 12 or 16, wherein the organic amine salt is selected from at least one of benzyl ammonium hydrohalide, γ-fluorobenzyl ammonium hydrohalide, phenethyl ammonium hydrohalide, γ-fluorophenethyl ammonium hydrohalide, n-butylamine hydrohalide, isobutylamine hydrohalide, halobutylammonium hydrohalide, halopropylammonium hydrohalide or 1-naphthylamine hydrohalide.
The method according to claim 16, wherein the perovskite antisolvent is at least one of tetrahydrofuran, acetonitrile, and dimethoxyethanol.
The method according to claim 16, wherein a mixed layer containing lead halide covering the two-dimensional perovskite seed crystal is formed on the surface of one side of the first carrier transport layer having the two-dimensional perovskite seed crystal by a dual-source co-evaporation method or a vapor deposition method.
The method according to any one of claims 8 to 20, wherein the two-dimensional three-dimensional bulk phase hybrid perovskite solar cell prepared by the method is the two-dimensional three-dimensional bulk phase hybrid perovskite solar cell according to any one of claims 1 to 7.
A solar cell, comprising a perovskite composite layer, wherein the perovskite composite layer comprises a two-dimensional perovskite layer and a three-dimensional perovskite layer stacked;

At least part of the two-dimensional perovskite in the two-dimensional perovskite layer is arranged along an interface perpendicular to the three-dimensional perovskite layer and the two-dimensional perovskite layer.
The solar cell according to claim 22, wherein at least a portion of the two-dimensional perovskite in the two-dimensional perovskite layer is arranged along an interface parallel to the three-dimensional perovskite layer and the two-dimensional perovskite layer.
The solar cell according to claim 22 or 23, wherein, in the two-dimensional perovskite layer, the two-dimensional perovskite perpendicular to the interface is a first two-dimensional perovskite, and the two-dimensional perovskite parallel to the interface is a second two-dimensional perovskite, and the content of the first two-dimensional perovskite layer gradually decreases from a side surface close to the three-dimensional perovskite layer to a side surface away from the three-dimensional perovskite layer.
The solar cell according to claim 24, wherein, in the two-dimensional perovskite layer, the content of the second two-dimensional perovskite layer gradually increases from a surface side close to the three-dimensional perovskite layer to a surface side away from the three-dimensional perovskite layer.
The solar cell according to claim 23, wherein, in the two-dimensional perovskite layer, the ratio of the content of the first two-dimensional perovskite to the content of the second two-dimensional perovskite is (1-4):1.
The solar cell according to claim 23, wherein the solar cell further comprises a substrate, and the substrate has a smooth surface or a velvet structure.
The solar cell according to claim 27, wherein when the substrate has a suede structure, both the three-dimensional perovskite layer and the two-dimensional perovskite layer are conformal to the substrate.
The solar cell according to claim 23, wherein the band gap of the perovskite composite layer is 1.65-1.69 eV.
A method for preparing a solar cell, comprising the following steps:

Preparation of three-dimensional perovskite layers;

preparing a two-dimensional perovskite layer on the surface of the three-dimensional perovskite layer;

At least part of the two-dimensional perovskite in the two-dimensional perovskite layer is arranged along an interface perpendicular to the three-dimensional perovskite layer and the two-dimensional perovskite layer.
The preparation method according to claim 30, wherein an organic amine salt solution is coated on the surface of the three-dimensional perovskite layer, and the organic amine salt solution reacts with residual lead halide in the three-dimensional perovskite layer to generate a two-dimensional perovskite layer.
According to the preparation method of claim 31, the organic amine salt solution and the surface of the three-dimensional perovskite layer are heated respectively, and then the heated organic amine salt solution is spin-coated on the surface of the heated three-dimensional perovskite layer, and after the spin coating is completed, annealing is performed to form a two-dimensional perovskite layer.
The preparation method according to claim 31 or 32, wherein the organic amine salt solution is formed by dissolving an organic amine salt in solvent one.
The preparation method according to claim 31, wherein the organic amine salt solution is formed by dissolving an organic amine salt and an additive in solvent one.
The preparation method according to claim 31, wherein the organic amine salt solution is formed by mixing an organic amine salt, solvent one and solvent two.
The preparation method according to any one of claims 31 to 35, wherein the organic amine salt is selected from RP type organic amine salt, DJ type organic amine salt or ACI type organic amine salt;

The concentration of the organic amine salt in the organic amine salt solution is 0.2-0.5 mol/l;

The first solvent is isopropanol or ethanol;

The second solvent is one of chlorobenzene, ethyl acetate, toluene, N-methylpyrrolidone or γ-butyrolactone;

The volume ratio of the solvent 1 to the solvent 2 is (2-9):1.
The preparation method according to claim 34, wherein the additive is one of ammonium chloride, ammonium thiocyanate, methylammonium chloride and ammonium thiocyanate;

The concentration of the additive is 2-15 mg/mL.
The preparation method according to any one of claims 30 to 37, wherein the prepared solar cell is the solar cell according to any one of claims 22 to 29.
A solar cell, comprising a substrate, wherein a first carrier transport layer, a two-dimensional three-dimensional bulk mixed perovskite absorption layer and a second carrier transport layer are sequentially stacked on one side surface of the substrate;

The two-dimensional and three-dimensional bulk mixed perovskite absorption layer contains two-dimensional perovskite and three-dimensional perovskite, and the two-dimensional perovskite is uniformly dispersed in the three-dimensional perovskite.
The solar cell according to claim 39, wherein the mass ratio of the two-dimensional perovskite to the three-dimensional perovskite is 1:(2-9).
The solar cell according to claim 39, wherein the grains of the two-dimensional perovskite The size distribution is between 80-150nm accounting for more than 90%.
The solar cell according to claim 39, wherein the grain size distribution of the three-dimensional perovskite is more than 90% in the range of 500-800 nm.
The solar cell according to any one of claims 39 to 42, wherein the substrate is a silicon-based cell or a glass substrate.
A method for preparing a solar cell, comprising the following steps:

preparing a substrate;

forming a first carrier transport layer on one side of the substrate;

Forming a two-dimensional and three-dimensional bulk mixed perovskite absorption layer on a surface of the first carrier transport layer facing away from the substrate;

Forming a second carrier transport layer on a surface of the two-dimensional and three-dimensional bulk mixed perovskite absorption layer that is away from the first carrier transport layer;

The two-dimensional and three-dimensional bulk mixed perovskite absorption layer contains two-dimensional perovskite and three-dimensional perovskite, and the two-dimensional perovskite is uniformly dispersed in the three-dimensional perovskite.
The preparation method according to claim 44, wherein the two-dimensional three-dimensional bulk mixed perovskite absorption layer is formed by the following method:

Preparing a three-dimensional perovskite precursor solution;

Adding organic amine and hydrohalic acid to the three-dimensional perovskite precursor solution and mixing them evenly to obtain a mixed solution;

The mixed solution is applied to a surface of the first carrier transport layer that is away from the substrate, thereby forming the two-dimensional and three-dimensional bulk mixed perovskite absorption layer.
The preparation method according to claim 45, wherein the application is spin coating, and an anti-solvent is dripped on the surface coated with the mixed liquid before the spin coating is completed, thereby forming the two-dimensional three-dimensional bulk mixed perovskite absorption layer.
The preparation method according to claim 45, wherein the volume ratio of the mixed solution of the organic amine and the hydrohalic acid to the perovskite precursor solution is 1:(45-65), preferably 1:(48-52).
The preparation method according to claim 45, wherein the volume ratio of the hydrohalic acid to the organic amine is (0.7-1.2):1, preferably (0.9-1.1):1.
The preparation method according to claim 45, wherein the hydrohalic acid is selected from one of hydroiodic acid, hydrobromic acid or hydrochloric acid.
The preparation method according to claim 45, wherein the organic amine is selected from one of benzylamine, γ-fluorobenzylamine, phenethylamine, γ-fluorophenethylamine, n-butylamine, isobutylamine, halobutylamine, halopropylamine or 1-naphthylamine.
The preparation method according to claim 45, wherein the perovskite precursor solution is a ternary perovskite precursor solution.
The preparation method according to any one of claims 45 to 51, wherein the prepared solar cell is the solar cell according to any one of claims 39 to 44.