Perovskite solar cell based on three-dimensional APbI3 light absorption layer

Abstract

The utility model discloses a perovskite solar cell based on a three-dimensional APbI3 light absorption layer. A first functional layer used for passivating anion vacancies is arranged in a perovskite light absorption layer close to one side of a hole transport layer; the first functional layer is a metal halide layer; a second functional layer for passivating cation vacancies is arranged in the perovskite light absorption layer close to one side of the electron transport layer; the second functional layer is a metal oxide layer; and the thickness of the second functional layer is in gradient distribution along the height direction of the perovskite light absorption layer. The perovskite solar cell is simple in structure and reasonable in design, a first functional layer and a second functional layer are arranged on the two sides of a perovskite light absorption layer respectively, the problem of interface area defects on the two sides of the perovskite light absorption layer is solved through space cooperation of the first functional layer and the second functional layer, and full-coverage passivation of the perovskite light absorption layer and the interface defects is achieved. The gradient distribution more effectively inhibits the cation vacancy defect of the interface area, and maintains the intrinsic photoelectric characteristics of the perovskite light absorption layer.

Description

TECHNICAL FIELD

[0001] The utility model belongs to solid device technical field, concretely relates to a kind of perovskite solar cell based on three-dimensional APbI3 Light Absorption Layer. BACKGROUND

[0002] In recent years, perovskite solar cell becomes the research hotspot in photovoltaic field due to its high photoelectric conversion efficiency, low cost solution preparation process and other advantages. Among them, three-dimensional APbI3 Perovskite Light Absorption Layer is widely used due to its excellent carrier diffusion length and light absorption performance. However, perovskite material is easy to form anion vacancy and cation vacancy at interface, and these defect states will significantly increase non-radiative recombination loss, reduce open-circuit voltage and fill factor of the cell, and ultimately affect the device efficiency.

[0003] Currently, industry usually adopts interface passivation technology to inhibit vacancy defect, for example: material component optimization: fill vacancy by introducing specific ions (such as Cs + , Rb + ), but this method involves modification of material itself, and may increase process complexity; structural design: insert functional layer, such as insulating oxide layer, between perovskite layer and transport layer, to reduce interface recombination by physical barrier.

[0004] However, the existing structure is mostly uniform single-layer structure, which is difficult to simultaneously consider the synergistic optimization of vacancy repair and carrier transport. Therefore, there is an urgent need for a technical scheme based on macro-structure innovation, which realizes efficient passivation effect without limiting specific materials, so as to improve the performance and stability of perovskite solar cell. UTILITY MODEL CONTENT

[0005] The technical problem to be solved by the utility model is to provide a perovskite solar cell based on three-dimensional APbI3 Light Absorption Layer, which has simple structure and reasonable design, and sets first functional layer and second functional layer on both sides of perovskite light absorption layer, so as to solve the defect problem of interface area on both sides of perovskite light absorption layer through spatial cooperation of the two, realize full coverage passivation of perovskite light absorption layer and interface defect, and more effectively inhibit cation vacancy defect in the interface area while maintaining intrinsic photoelectric properties of perovskite light absorption layer.

[0006] To solve the above technical problems, the utility model adopts the technical scheme of: a perovskite solar cell based on three-dimensional APbI3 Light Absorption Layer, which comprises transparent electrode layer, hole transport layer, perovskite light absorption layer, electron transport layer and metal electrode layer covered in sequence, characterized in that:

[0007] A first functional layer for passivating anion vacancies is arranged in the perovskite light absorption layer close to the side of the hole transport layer; the first functional layer is a metal halide layer.

[0008] A second functional layer for passivating cation vacancies is arranged in the perovskite light absorption layer close to the side of the electron transport layer; the second functional layer is a metal oxide layer; the thickness of the second functional layer is gradiently distributed along the height direction of the perovskite light absorption layer.

[0009] The perovskite solar cell based on the three-dimensional APbI3 light absorption layer, characterized in that the thickness of the second functional layer gradually decreases from the side close to the electron transport layer to the side far away.

[0010] The perovskite solar cell based on the three-dimensional APbI3 light absorption layer, characterized in that the second functional layer is composed of multiple sub-layers stacked together, the thickness of each sub-layer is different, forming a stepwise thickness distribution.

[0011] The perovskite solar cell based on the three-dimensional APbI3 light absorption layer, characterized in that the number of sub-layers is not less than 2, and the thickness difference between adjacent two layers is not less than 0.5 nm.

[0012] The perovskite solar cell based on the three-dimensional APbI3 light absorption layer, characterized in that the density of the second functional layer is gradiently distributed along the height direction of the perovskite light absorption layer.

[0013] The perovskite solar cell based on the three-dimensional APbI3 light absorption layer, characterized in that the density of the second functional layer gradually decreases from the side close to the electron transport layer to the side far away.

[0014] The perovskite solar cell based on the three-dimensional APbI3 light absorption layer, characterized in that the second functional layer is composed of multiple sub-layers stacked together, the density of each sub-layer is different, forming a stepwise density distribution.

[0015] The perovskite solar cell based on the three-dimensional APbI3 light absorption layer, characterized in that the distance between the second functional layer and the electron transport layer is L, d is the thickness of the perovskite light absorption layer, L = α × d, and α is valued at 1 / 4-1 / 2.

[0016] The perovskite solar cell based on the three-dimensional APbI3 light absorption layer, characterized in that the surface of the transparent electrode layer is provided with multiple convex protrusions in the form of semi-elliptical spherical structures.

[0017] The perovskite solar cell based on the three-dimensional APbI3 light absorption layer, characterized in that the convex protrusions in the form of semi-elliptical spherical structures are non-periodically arranged on the surface of the transparent electrode layer, and the edge distance between adjacent two protrusions is 0.1-0.6 times the maximum diameter.

[0018] The utility model discloses the following advantages compared with prior art:

[0019] 1. The utility model discloses simple structure, reasonable in design, realize and convenient operation.

[0020] 2. The utility model discloses that the first functional layer and the second functional layer are arranged respectively on both sides of perovskite light absorption layer, and the spatial cooperation of both solves the interface area defect problem of both sides of perovskite light absorption layer.

[0021] 3. In the utility model, the first functional layer is metal halide layer, and is used for passivating anion vacancy of perovskite light absorption layer, and the second functional layer is metal oxide layer, and is used for passivating cation vacancy of perovskite light absorption layer, double-layer physical protection realizes the full coverage passivation of perovskite light absorption layer and interface defect, and synchronously enhances the environmental stability of perovskite layer, delays performance attenuation, and promotes perovskite solar cell to commercial application.

[0022] 4. In the utility model, the thickness of the second functional layer gradient distribution along the height direction of perovskite light absorption layer, and the thickest place covers the interface area of high defect, can more effectively inhibit the cation vacancy defect of the interface area, reduces interface recombination loss, and improves the transmission efficiency of electron from perovskite light absorption layer to electron transport layer; The thinnest place is away from electron transport layer, can avoid excessive hindering the transmission of hole to hole transport layer, balances the extraction of electron and hole, and retains the light absorption capacity of perovskite light absorption layer simultaneously.

[0023] 5. In the utility model, more accurate interface engineering is realized through the double gradient regulation and control on three-dimensional space, and the thickness of the sublayer close to electron transport layer is thicker and the density is higher, provides more passivation sites to saturate interface defect state, provides stronger defect passivation capacity, and can more effectively passivate high concentration defects at the interface; The thickness of the sublayer away from electron transport layer is thinnest and the density is lowest, while maintaining moderate passivation capacity, maximumly reduces the hindering of carrier transmission, and maintains the intrinsic photoelectric property of perovskite light absorption layer.

[0024] 6. In the utility model, the convex of half-elliptical spherical structure is non-periodic arrangement on the surface of transparent electrode layer, and the non-periodic arrangement destroys coherence condition through disorder, makes the spectrum response more smooth, and the non-periodic structure is not sensitive to the angle of incident light, and is more suitable for diffuse light in actual environment.

[0025] In summary, the utility model discloses simple structure, reasonable in design is provided with first functional layer and second functional layer respectively on both sides of perovskite light absorption layer, and the spatial cooperation of both solves the interface area defect problem of both sides of perovskite light absorption layer, realizes the full coverage passivation of perovskite light absorption layer and interface defect, gradient distribution is more effective to inhibit the cation vacancy defect of the interface area, and simultaneously maintains the intrinsic photoelectric characteristic of perovskite light absorption layer.

[0026] The technical scheme of the utility model will be further described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is the structural schematic diagram of the utility model.

[0028] Figure 2 It is the structural schematic diagram of first functional layer and second functional layer of the utility model.

[0029] Figure 3 It is the structural schematic diagram of the utility model convex.

[0030] Figure 4 It is the structural schematic diagram of second functional layer in embodiment two of the utility model.

[0031] Figure 5 It is the structural schematic diagram of second functional layer in embodiment three of the utility model.

[0032] Figure 6 It is the structural schematic diagram of second functional layer in embodiment four of the utility model.

[0033] Mark explanation:

[0034] 1-transparent electrode layer;2-hole transport layer;3-first functional layer;

[0035] 4-perovskite light absorption layer;5-second functional layer;6-electron transport layer;

[0036] 7-metal electrode layer. DETAILED DESCRIPTION

[0037] The utility model will be further described in detail below with reference to the drawings and embodiments.

[0038] It is to be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0039] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0040] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0041] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0042] Example 1

[0043] like Figure 1 , Figure 2 and Figure 3 As shown, a perovskite solar cell based on a three-dimensional APbI3 light-absorbing layer in this application includes a transparent electrode layer 1, a hole transport layer 2, a perovskite light-absorbing layer 4, an electron transport layer 6, and a metal electrode layer 7, which are sequentially covered.

[0044] In actual use, under light conditions, the perovskite light absorption layer 4 can absorb photons, and after absorbing the photons, the valence band electrons will transition to the conduction band to form electron-hole pairs, and then the conduction band electrons will be injected into the conduction band of the electron transport layer 6, while the holes are extracted and transported to the hole transport layer 2, so that the electron-hole pairs are separated. The electrons in the electron transport layer 6 flow to the negative electrode through the metal electrode layer 7, and the holes in the hole transport layer 2 flow to the positive electrode through the transparent electrode layer 1, forming a closed loop. In the external circuit, the directional movement of the electrons produces an electric current, and the reverse migration of the holes maintains charge balance, ultimately realizing the conversion of solar energy to electrical energy.

[0045] In one possible embodiment, the transparent electrode layer 1 uses ITO glass as a substrate, is flat, has a thickness of about 3 nm, and has a uniform and dense surface with high light transmittance. The hole transport layer 2 uses Spiro-OMeTAD as a hole transport material, and the thin film has a thickness of 100-300 nm, and is usually doped with Li-TFSI to improve the hole mobility. The perovskite light absorption layer 4 has a polycrystalline thin film structure, a thickness of 400-600 nm, and is composed of cubic or tetragonal APbI3 grains, has a high light absorption coefficient and a long carrier diffusion length, and ensures efficient light absorption and charge separation. The electron transport layer 6 uses a SnO3 thin film, and the thin film has a thickness of 20-50 nm and has high electron mobility, which can effectively extract electrons from the perovskite light absorption layer 4 and suppress charge recombination. The metal electrode layer 7 is made of gold Au or silver Ag into a flat electrode, has a thickness of 10-20 nm, and has high conductivity and stability.

[0046] The present application is provided with a first functional layer 3 for passivating anion vacancies in the perovskite light absorption layer 4 close to the hole transport layer 2 side; the first functional layer 3 is a metal halide layer.

[0047] In a perovskite solar cell, anions are easily lost at the interface between the perovskite light absorption layer 4 and the hole transport layer 2, forming anion vacancies, for example, for a three-dimensional APbI3 light absorption layer, anion vacancies refer to the loss of iodine ions I- to form iodine vacancies. These anion vacancies can capture photo-generated electrons, leading to non-radiative recombination, reducing carrier lifetime, promoting ion migration, and affecting device stability and efficiency. Therefore, the first functional layer 3 is provided to repair the anion vacancies.

[0048] Metal halides have been extensively studied for passivating defects in perovskites. They can be introduced via solution spin-coating, vapor deposition, or post-processing diffusion, making them compatible with mainstream perovskite fabrication processes. In one possible embodiment, the metal halide layer of the first functional layer 3 is a halide alkali metal nanosheet or a halide alkaline earth metal compound nanosheet. The metal halide layer can employ metal halides such as SnBr2, PbBr2, ZnBr2, KBr, CsBr, PbCl2, KCl, and ZnCl2. Halogen ions such as Br- and Cl- directly replace missing I- vacancies, reducing deep-level defects. Passivating anion vacancies with metal halide layers is a conventional technique in perovskite devices, particularly suitable for applications requiring high efficiency and high stability.

[0049] Within the perovskite light-absorbing layer 4 near the electron transport layer 6, a second functional layer 5 for passivating cation vacancies is provided; the second functional layer 5 is a metal oxide layer; the thickness of the second functional layer 5 is gradient-distributed along the height direction of the perovskite light-absorbing layer 4.

[0050] In perovskite solar cells, cation vacancies are easily formed at the interface between the perovskite light-absorbing layer 4 and the electron transport layer 6. For example, in the case of a three-dimensional APbI3 light-absorbing layer, the cation vacancy refers to Pb. 2+ Vacancy, Pb 2+ Vacancies can lead to nonradiative recombination, which degrades device performance. Therefore, a second functional layer 5 is provided to repair cation vacancies.

[0051] The metal oxide layer is used to repair cation vacancies in perovskite. It can be introduced via solution spin coating, vapor deposition, or post-treatment modification, ensuring compatibility with mainstream perovskite preparation processes. In one possible embodiment, the metal oxide layer of the second functional layer 5 is a titanate compound nanosheet or other metal oxide nanosheet. For example, SrTiO3, Al2O3, SnO2, TiO2, MgO, ZnO, etc., can be used. This allows for the repair of uncoordinated Pb in the perovskite. 2+ Formation of Pb-O bonds, passivation of Pb 2+ Vacancies passivate deep-level defects.

[0052] This application provides a first functional layer 3 and a second functional layer 5 on both sides of the perovskite light-absorbing layer 4. The spatial arrangement of the two layers solves the problem of heterogeneous defects on both sides of the perovskite light-absorbing layer 4. The first functional layer 3 is used to passivate the anion vacancies of the perovskite light-absorbing layer 4, and the second functional layer 5 is used to passivate the cation vacancies of the perovskite light-absorbing layer 4. The double-layer physical protection achieves full-coverage passivation of the perovskite light-absorbing layer 4 and interface defects, simultaneously enhancing the environmental stability of the perovskite layer, delaying performance degradation, and promoting the commercial application of perovskite solar cells.

[0053] In actual use, the thickness of the second functional layer 5 is gradiently distributed along the height direction of the perovskite light absorption layer 4, which means that the thickness of the second functional layer 5 gradually decreases from the side close to the electron transport layer 6 to the side far from the electron transport layer 6.

[0054] Moreover, the concentration of the electron and hole pairs in the perovskite light absorption layer 4 is generally gradiently distributed, and therefore the thickness of the second functional layer 5 is gradiently distributed to match the same. The specific principle is as follows: the interface between the electron transport layer 6 and the perovskite light absorption layer 4 is a key region with high defect density, and therefore the side of the second functional layer 5 close to the electron transport layer 6 has a relatively high thickness, and the second functional layer 5 covers the interface region with high defects at the thickest place, which can more effectively inhibit the cation vacancy defects in the interface region, reduce the interface recombination loss, and improve the transmission efficiency of electrons from the perovskite light absorption layer 4 to the electron transport layer 6; the side of the second functional layer 5 far from the electron transport layer 6 has a relatively low thickness, and the internal demand for electron transmission of the perovskite light absorption layer 4 is reduced, and therefore this side has a relatively low thickness, which can avoid excessive hindering of the transmission of holes to the hole transport layer 2, balance the extraction of electrons and holes, and meanwhile retain the light absorption capability of the perovskite light absorption layer 4.

[0055] In this embodiment, the density of the second functional layer 5 is gradiently distributed along the height direction of the perovskite light absorption layer 4. The density of the second functional layer 5 gradually decreases from the side close to the electron transport layer 6 to the side far from the electron transport layer 6.

[0056] In actual use, in the perovskite solar cell, the second functional layer 5 is arranged in the perovskite light absorption layer 4 close to the electron transport layer 6, and the second functional layer 5 serves as a passivation layer for passivating cation vacancies and has a gradiently distributed density. The interface between the electron transport layer 6 and the perovskite light absorption layer 4 is a key region with high defect density, and therefore the side of the second functional layer 5 close to the electron transport layer 6 has a relatively high density, and the second functional layer 5 covers the interface region with high defects at the highest density place, which can effectively passivate the interface defects, reduce non-radiative recombination, and promote electron transmission. The side far from the electron transport layer 6 has a relatively low density, which is beneficial to maintaining the intrinsic photoelectric properties of the perovskite light absorption layer 4 and avoiding hindering of hole transmission or light absorption. The gradiently distributed density not only can balance defect passivation and carrier extraction efficiency, but also can smooth the energy band structure, and improve the long-term stability of the device.

[0057] In this embodiment, the distance between the second functional layer 5 and the electron transport layer 6 is L, d is the thickness of the perovskite light absorption layer 4, L = a x d, and a is 1 / 4-1 / 2. In a possible embodiment, a is 1 / 3. It should be noted that the distance between the first functional layer 3 and the hole transport layer 2 is L2, d is the thickness of the perovskite light absorption layer 4, L2 = a x d, and a is 1 / 4-1 / 2. In a possible embodiment, a is 1 / 3.

[0058] If the second functional layer 5 is too close to the electron transport layer 6, it will create additional interface defects; if the second functional layer 5 is too far from the electron transport layer 6, it will be detrimental to maintaining the intrinsic photoelectric properties of the perovskite light absorption layer 4. Moreover, since photogenerated electrons need to migrate from the perovskite light absorption layer 4 to the electron transport layer 6, an excessively large distance will increase the recombination probability. Therefore, in order to achieve a balance between electron diffusion length and recombination probability and improve passivation effect, the distance between the second functional layer 5 and the electron transport layer 6 is 1 / 4 to 1 / 2 of the thickness of the perovskite light absorption layer 4.

[0059] In this embodiment, the surface of the transparent electrode layer 1 is provided with a plurality of protrusions with semi-elliptical spherical structures.

[0060] Traditional planar structures have weak absorption of near-infrared light. The curved surface geometry of the semi-elliptic spherical structure can scatter the incident light multiple times, extending the propagation path of the incident light within the perovskite light absorption layer 4. This eliminates the need for expensive anti-reflective coatings or optical anti-reflective films, improving the photoelectric conversion efficiency of the battery without increasing material costs.

[0061] The protrusions of the semi-elliptic structure are arranged aperiodically on the surface of the transparent electrode layer 1, with the edge distance between two adjacent protrusions being 0.1-0.6 times the maximum diameter D. The aperiodic arrangement disrupts the coherence condition through disorder, resulting in a smoother spectral response. The aperiodic structure is insensitive to the incident light angle, making it more suitable for diffuse light in real-world environments.

[0062] To achieve optimal performance, the edge distance between two adjacent protrusions is 0.2-0.5 times the maximum diameter D, resulting in high protrusion coverage and improved light scattering efficiency. In one possible embodiment, the ratio of the height to the diameter of the semi-ellipsoidal structure is 0.3-0.6, with the diameter ranging from 200 nm to 1000 nm.

[0063] For large-area fabrication of semi-ellipsoidal protrusions, electron beam lithography or nanoimprint lithography is used; for small-scale fabrication in the laboratory, spin coating is used.

[0064] Example 2

[0065] like Figure 4 As shown, unlike Embodiment 1, the second functional layer 5 is composed of multiple sub-layers 51 stacked together, with each sub-layer 51 having a different thickness, forming a stepped thickness distribution.

[0066] In Example 1, the thickness of the second functional layer 5 changes continuously and gradually, without a clear interface. This continuous thickness variation creates a smooth bandgap, suitable for roll-to-roll continuous production. In this example, the second functional layer 5 is composed of multiple sub-layers 51 stacked together. The thickness of each sub-layer 51 changes abruptly, employing a layered, stepped thickness distribution design to precisely passivate the spatial differences in defect distribution within the perovskite light-absorbing layer 4. This stepped thickness distribution allows for independent and precise control of the thickness of each sub-layer, making parameters easily controllable, compatible with existing conventional multilayer deposition equipment, and suitable for batch production.

[0067] The layered structure can also integrate a variety of metal oxides, and the metal oxides of each sublayer 51 can be different.

[0068] The number of sublayers 51 is not less than two, and the thickness difference between two adjacent layers is not less than 0.5 nm. In one possible embodiment, from the side closer to the electron transport layer 6 to the side farther away from the electron transport layer 6, there are sequentially a first metal oxide layer and a second metal oxide layer.

[0069] In one possible embodiment, there are three sublayers 51. The sublayers closest to the electron transport layer 6 have a thickness of 2-3 nm, the sublayers furthest from the electron transport layer 6 have a thickness of 0.5-1 nm, and the middle sublayer has a thickness of 1-2 nm. The metal oxides of the three sublayers are all of the same type, such as SrTiO3, Al2O3, SnO2, TiO2, MgO, and ZnO.

[0070] In one possible embodiment, there are three sublayers 51. The sublayer closest to the electron transport layer 6 has a thickness of 2-3 nm, the middle sublayer has a thickness of 1-2 nm, and the sublayer furthest from the electron transport layer 6 has a thickness of 0.5-1 nm. The three sublayers are made of different metal oxides, namely Al2O3, ZnO, and MgO.

[0071] Example 3

[0072] like Figure 5 As shown, in this embodiment, the second functional layer 5 is composed of multiple sub-layers 51 stacked together, with each sub-layer 51 having a different density, forming a stepped density distribution.

[0073] The second functional layer 5 adopts a stepped density distribution design, and by arranging a high-density sublayer 51 close to the electron transport layer 6, more passivation sites are provided to saturate the interface defect state, which can more effectively passivate the high-concentration defects at the interface. The density of the sublayer 51 extending to the inside of the perovskite light absorption layer 4 gradually decreases, which not only ensures the moderate passivation of the bulk defects, but also avoids the hindering of excessive metal oxides to the carrier transport, thereby maintaining the intrinsic photoelectric properties of the perovskite light absorption layer 4. This stepped density distribution adapts to the spatial variation characteristics of the defect distribution in the perovskite light absorption layer 4, and by adjusting the density of each sublayer, additional optical loss or electrical barrier can be avoided, and the performance during the period can be optimized.

[0074] In one possible embodiment, the number of sublayers 51 is 3, the density of the sublayer close to the electron transport layer 6 is 6.8 g / cm 3 , the density of the middle sublayer is 6.2 g / cm 3 , and the density of the sublayer far away from the sublayer close to the electron transport layer 6 is 5.5 g / cm 3 . The metal oxides of the three sublayers are the same among SrTiO3, Al2O3, SnO2, TiO2, MgO, ZnO and the like. The programmed atomic layer deposition technology can be realized on a standard ALD device, and is compatible with the perovskite precursor solution coating process.

[0075] Embodiment Four

[0076] As shown in Figure 6 , in this embodiment, the second functional layer 5 is stacked by a plurality of sublayers 51, and the thicknesses of the sublayers 51 are different, forming a stepped thickness distribution.

[0077] The number of sublayers 51 is not less than 2, and the thickness difference between adjacent two layers is not less than 0.5 nm.

[0078] The second functional layer 5 is stacked by a plurality of sublayers 51, and the densities of the sublayers 51 are different, forming a stepped density distribution.

[0079] In this embodiment, the sublayer close to the electron transport layer 6 has a relatively high thickness and density, provides more passivation sites to saturate the interface defect state, provides stronger defect passivation ability, and can more effectively passivate the high-concentration defects at the interface. The sublayer away from the electron transport layer 6 has the thinnest thickness and the lowest density, while maintaining the moderate passivation ability, maximally reduces the hindering to the carrier transport, and maintains the intrinsic photoelectric properties of the perovskite light absorption layer 4. Through the double gradient regulation in three-dimensional space, more accurate interface engineering is realized.

[0080] In one possible embodiment, the number of sublayers 51 is 3, the thickness of the sublayer close to the electron transport layer 6 is 2-3 nm, and the density is 6.8 g / cm3 ; the intermediate sublayer has a thickness of 1-2 nm and a density of 6.2 g / cm 3 ; the sublayer away from the electron transport layer 6 has a thickness of 0.5-1 nm and a density of 5.5 g / cm 3 The metal oxides of the three sublayers are all the same kind of metal oxides selected from SrTiO3, Al2O3, SnO2, TiO2, MgO, ZnO, etc. The technology of programmed atomic layer deposition can be realized on a standard ALD device, and is compatible with the coating process of perovskite precursor solution.

[0081] Wherein, the content not described in detail in the specification belongs to the prior art known to those skilled in the art.

[0082] The above is only an embodiment of the present application, and does not limit the present application in any way. Any simple modification, change, and equivalent structural change made according to the technical essence of the present application to the above embodiment are still within the protection scope of the technical solution of the present application.

Claims

1. A perovskite solar cell based on a three-dimensional APbI3 light absorption layer, comprising a transparent electrode layer (1), a hole transport layer (2), a perovskite light absorption layer (4), an electron transport layer (6) and a metal electrode layer (7) covered in sequence, characterized in that: a first functional layer (3) for passivating anion vacancies is arranged in the perovskite light absorption layer (4) close to the side of the hole transport layer (2); the first functional layer (3) is a metal halide layer; a second functional layer (5) for passivating cation vacancies is arranged in the perovskite light absorption layer (4) close to the side of the electron transport layer (6); the second functional layer (5) is a metal oxide layer; the thickness of the second functional layer (5) is gradiently distributed along the height direction of the perovskite light absorption layer (4). The thickness of the second functional layer (5) gradually decreases from the side close to the electron transport layer (6) to the side far away. The second functional layer (5) is composed of a plurality of sub-layers (51), each sub-layer (51) has a different thickness, forming a stepped thickness distribution.

2. The perovskite solar cell based on three-dimensional APbI3 light absorption layer according to claim 1, characterized in that: The number of sub-layers (51) is not less than 2, and the thickness difference between adjacent two layers is not less than 0.5 nm.

3. The perovskite solar cell based on three-dimensional APbI3 light absorption layer according to claim 1, characterized in that: The density of the second functional layer (5) is gradiently distributed along the height direction of the perovskite light absorption layer (4).

4. The perovskite solar cell based on three-dimensional APbI3 light absorption layer according to claim 3, characterized in that: The density of the second functional layer (5) gradually decreases from the side close to the electron transport layer (6) to the side far away.

5. The perovskite solar cell based on three-dimensional APbI3 light absorption layer according to claim 1, characterized in that: The second functional layer (5) is composed of a plurality of sub-layers (51), each sub-layer (51) has a different density, forming a stepped density distribution.

6. The perovskite solar cell based on three-dimensional APbI3 light absorption layer according to claim 5, characterized in that: The distance between the second functional layer (5) and the electron transport layer (6) is L, d is the thickness of the perovskite light absorption layer (4), L = α × d, and α is 1 / 4-1 / 2.

7. The perovskite solar cell based on three-dimensional APbI3 light absorption layer according to claim 1 or 3, characterized in that: The surface of the transparent electrode layer (1) is provided with a plurality of convex protrusions in a semi-elliptical spherical structure.

8. The perovskite solar cell based on three-dimensional APbI3 light absorption layer according to claim 1, characterized in that: The semi-elliptical spherical structure protrusions are arranged in a non-periodic manner on the surface of the transparent electrode layer (1), and the edge distance between adjacent two protrusions is 0.1-0.6 times the maximum diameter.

9. The perovskite solar cell based on three-dimensional APbI3 light absorption layer according to claim 1, characterized in that: ​ 10. The perovskite solar cell based on three-dimensional APbI3 light absorption layer according to claim 9, characterized in that: ​

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