Perovskite solar cell and preparation method thereof

Abstract

The invention discloses a perovskite solar cell and a preparation method thereof, and relates to the technical field of solar cell manufacturing, and the perovskite solar cell specifically comprises a substrate, a hole transport layer, a perovskite layer, a passivation layer, an electron transport layer and an electrode which are stacked from bottom to top, and also comprises a buffer layer arranged between the perovskite layer and the passivation layer. Wherein the buffer layer is formed by a polycyclic aromatic conjugated polymer. According to the embodiment, the buffer layer is arranged between the perovskite layer and the passivation layer, so that the perovskite layer is protected, and the solvent in the passivation layer is prevented from dissolving methylamine in the perovskite layer. According to the perovskite solar cell, the buffer layer is made of the polycyclic aromatic conjugated polymer without reaction activation sites, it is guaranteed that the buffer layer cannot react with the perovskite layer and the passivation layer, repeatability of the perovskite solar cell is guaranteed, and meanwhile the overall performance of the perovskite solar cell cannot be affected.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cell manufacturing, and in particular to a perovskite solar cell and a preparation method thereof. Background Art

[0002] The main structure of existing perovskite solar cells usually includes a substrate, a hole transport layer, a perovskite layer, an electron transport layer and an electrode stacked from bottom to top. In order to improve the charge transport defects of the perovskite layer prepared by the solution method, the prior art uses aniline salt as a passivation material to passivate the surface of the perovskite layer and prepare a passivation layer to improve the overall performance of the perovskite solar cell.

[0003] However, due to the particularity of aniline salts, they can only be dissolved in alcohol solvents such as isopropyl alcohol, which can dissolve the methylamine component of the perovskite layer. Although the charge transfer performance is improved through passivation, the repeatability of perovskite solar cells is greatly reduced. The current solution is to use perovskite materials without methylamine components. Although this can avoid the problem of the passivation layer dissolving the perovskite layer, the thermal stability is significantly reduced, and it still cannot meet the use requirements of perovskite solar cells. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a perovskite solar cell and a preparation method thereof, wherein a buffer layer is provided between the perovskite layer and the passivation layer to protect the perovskite layer so as to prevent the solvent in the passivation layer from dissolving the methylamine component in the perovskite layer. Among them, by setting the material of the buffer layer to a polycyclic aromatic conjugated polymer without a reaction activation site, it is ensured that the buffer layer will not react with the perovskite layer and the passivation layer, which not only ensures the repeatability of the perovskite solar cell, but also does not affect the overall performance of the perovskite solar cell.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a perovskite solar cell, comprising: a substrate, a hole transport layer, a perovskite layer, a passivation layer, an electron transport layer and an electrode stacked from bottom to top; and also comprising a buffer layer arranged between the perovskite layer and the passivation layer; wherein the buffer layer is formed of a polycyclic aromatic conjugated polymer.

[0007] Optionally, the buffer layer has a thickness of 1 nm to 10 nm.

[0008] Optionally, the polycyclic aromatic conjugated polymer includes one or more of polyacenaphthene, polypyridine, polypyrrole, and polypyrimidine.

[0009] Optionally, the material of the perovskite layer is a material containing methylamine ions (CH3 NH 3 + ) of the perovskite material, that is, the general chemical formula of the perovskite material is ABX3, then the A ions include at least CH 3 NH 3 + More preferably, the A ions include CH 3 NH 3 + , or CH 3 NH 3 + With (HC (NH) 2 ) 2 + , Cs + and Rb + At least one combination of the B ions including Pb 2+ Sn 2+ and Sr 2+ At least one of the X ions includes Br - ,I - and Cl - At least one of;

[0010] The material of the passivation layer is aniline salt, and the solvent used to prepare the passivation layer is an alcohol solvent.

[0011] Optionally, the thickness of the perovskite layer is 100 nm to 1000 nm; and / or the thickness of the passivation layer is 0.5 nm to 10 nm.

[0012] Optionally, the material of the hole transport layer is a self-assembled monolayer material containing a phosphate group, including one or more of [2-(9H-carbazole-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid and [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid; and / or, the material of the electron transport layer is one or more of fullerene or fullerene derivatives.

[0013] Optionally, the hole transport layer 2 has a thickness of 0.5 nm to 10 nm; and / or the electron transport layer 6 has a thickness of 5 nm to 50 nm.

[0014] Optionally, it also includes: a modification layer arranged between the electron transport layer and the electrode; the material of the modification layer includes at least one of bathocuproin, lithium fluoride, molybdenum oxide, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline and magnesium fluoride; and / or the thickness of the modification layer is 1nm~20nm.

[0015] In a second aspect, the present invention provides a method for preparing the above-mentioned perovskite solar cell, comprising:

[0016] A hole transport layer, a perovskite layer, a buffer layer, a passivation layer, an electron transport layer and an electrode are sequentially prepared from the inside to the outside on one side in the thickness direction of the substrate; or, a hole transport layer, a perovskite layer, a buffer layer, a passivation layer, an electron transport layer, a modification layer and an electrode are sequentially prepared from the inside to the outside on one side in the thickness direction of the substrate.

[0017] Optionally, the step of preparing the buffer layer includes:

[0018] Using chloroform or chlorobenzene as a solvent to dissolve the polycyclic aromatic conjugated polymer to obtain a buffer layer solution;

[0019] The buffer layer solution is coated on the perovskite layer to obtain the buffer layer on the perovskite layer.

[0020] The technical solution of the first aspect of the above invention has the following advantages or beneficial effects: by setting a buffer layer between the perovskite layer and the passivation layer, the perovskite layer is protected to prevent the solvent in the passivation layer from dissolving the methylamine component in the perovskite layer. Among them, by setting the material of the buffer layer to a polycyclic aromatic conjugated polymer without a reaction activation site, it is ensured that the buffer layer will not react with the perovskite layer and the passivation layer, which not only ensures the repeatability of the perovskite solar cell, but also does not affect the overall performance of the perovskite solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to better understand the present invention and do not constitute an improper limitation of the present invention.

[0022] Figure 1 A schematic cross-sectional structure diagram of a perovskite solar cell provided by an embodiment of the present invention is shown;

[0023] Figure 2 is a schematic diagram of the main process of preparing a buffer layer according to an embodiment of the present invention;

[0024] Figure 3 It is a schematic diagram of the main process of preparing a passivation layer according to an embodiment of the present invention.

[0025] The reference numerals are as follows:

[0026] 1-substrate; 2-hole transport layer; 3-perovskite layer; 4-buffer layer; 5-passivation layer; 6-electron transport layer; 7-modification layer; 8-electrode. DETAILED DESCRIPTION

[0027] A solar cell is a photoelectric semiconductor sheet that uses sunlight to generate electricity directly. It is also called a "solar chip" or "photovoltaic cell". As long as it is illuminated by light that meets certain illumination conditions, it can instantly output voltage and generate current in the presence of a circuit. In physics, it is called solar photovoltaic (PV), or photovoltaic for short. In order to conveniently and clearly describe the method for preparing a solar cell and the solar cell of the present invention, the following exemplary embodiments of the present invention are described in conjunction with the accompanying drawings, which include various details of the embodiments of the present invention to facilitate understanding, and they should be considered as merely exemplary. Therefore, those of ordinary skill in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for the sake of clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0028] Figure 1 FIG. 4 shows a schematic cross-sectional structure diagram of a perovskite solar cell provided by an embodiment of the present invention, such as Figure 1 As shown, the perovskite solar cell provided by the present invention includes a substrate 1, a hole transport layer 2, a perovskite layer 3, a passivation layer 5, an electron transport layer 6 and an electrode 8 stacked from bottom to top; and also includes a buffer layer 4 arranged between the perovskite layer 3 and the passivation layer 5; wherein the buffer layer 4 is formed of a polycyclic aromatic conjugated polymer.

[0029] In the prior art, due to the absence of the buffer layer 4, the solvent in the passivation layer 5 will dissolve and destroy the methylamine component in the perovskite layer 3, causing the overall utilization efficiency of the perovskite solar cell to decrease. As the number of uses increases, the methylamine content in the perovskite layer 3 becomes lower and lower, resulting in a decrease in the repeatability of the perovskite solar cell. Therefore, the embodiment of the present invention isolates the passivation layer 5 from the influence of the perovskite layer 3 by providing a buffer layer 4.

[0030] It is understandable that in order not to have a negative impact on other properties of the perovskite solar cell, the buffer layer 4 material added in the embodiment of the present invention needs to be strictly screened and verified. In this regard, the inventors found that the polycyclic aromatic conjugated polymer belongs to a type of conjugated conductive polymer, and the molecule contains only carbon, hydrogen and nitrogen elements. The film structure formed is dense and uniform, which can effectively block the penetration of the solvent in the passivation layer 5, thereby achieving the effect of isolating the passivation layer 5 from the perovskite layer 3. At the same time, the polycyclic aromatic conjugated polymer has no reaction activation site and will not chemically react with any of the perovskite layer 3 or the passivation layer 5. Therefore, it is suitable to be used as a buffer layer 4 and arranged between the perovskite layer 3 and the passivation layer 5. It can be seen that the selection of the buffer layer 4 material in the embodiment of the present invention can not only ensure that it does not react with the adjacent materials, but also form a relatively dense layer film structure, which can achieve an effective isolation effect. Specifically, for the selection of the specific material of the buffer layer 4, the selected polycyclic aromatic conjugated polymer can include one or more of polyacenaphthene, polypyridine, polypyrrole, and polypyrimidine.

[0031] In an optional embodiment, the thickness of the buffer layer 4 can be set to 1nm~10nm, preferably 2nm~5nm, such as 2nm, 3nm, 4nm, 5nm, etc. As for the setting of the thickness of the buffer layer 4, if the thickness is too thin, it cannot fully block the penetration of the solvent in the passivation layer 5, and the blocking effect is poor; if the thickness is too thick, it is not conducive to carrier transmission, which will cause a decrease in the fill factor, thereby affecting the overall performance of the perovskite solar cell. Therefore, after multiple experiments, the embodiment of the present invention sets the thickness of the buffer layer 4 to 2nm~5nm.

[0032] Regarding the selection of the hole transport layer 2 material, in an optional embodiment, the hole transport layer 2 material is a self-assembled monolayer material containing a phosphate group; including one or more of [2-(9H-carbazole-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid and [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid. In perovskite solar cells, the hole transport layer 2 mainly plays the role of collecting and transporting holes, achieving effective separation of electrons and holes, and protecting the perovskite layer 3 from oxygen and water vapor corrosion. Therefore, it is necessary to select a self-assembled monolayer material containing a phosphate group to provide sufficient conductive properties.

[0033] In an optional embodiment, the thickness of the hole transport layer 2 is 0.5nm to 10nm, for example, 0.5nm, 1.5nm, 3nm, 4.5nm, 7nm, 8.5nm, 10nm, etc. Among them, as the thickness of the hole transport layer 2 increases, the film grain size and crystallinity of the perovskite layer 3 will change accordingly, thereby affecting the overall voltage, fill factor and photoelectric conversion efficiency of the perovskite solar cell. It is understandable that when the thickness of the hole transport layer 2 is too large, it will cause poor contact between the anode and the electrolyte, thereby affecting the overall stability of the perovskite solar cell.

[0034] For the perovskite layer 3, in an optional embodiment, the material of the perovskite layer 3 is a material containing methylamine ions (CH 3 NH 3 + ) of the perovskite material, that is, the general chemical formula of the perovskite material is ABX3, then the A ions include at least CH 3 NH 3 + More preferably, the A ions include CH 3 NH 3 + , or CH 3 NH 3 + With (HC (NH) 2 ) 2 + , Cs + and Rb + At least one combination of; B ions are generally metal cations, preferably including Pb 2+ Sn 2+ and Sr 2+ At least one of the following, the X ion is usually a halogen anion, preferably including Br - ,I - and Cl - At least one of .

[0035] In a further optional embodiment, the material of the perovskite layer 3 may include MAPbI 3 MAPbI 2.5 Br 0.5 MAPbI 1.8 Br 1.2 MAPbI 1.2 Br 1.8 MAPbI 0.9 Br 2.1 MAPbBr 3 、MASnI 3 MAPb 0.75 Sn 0.25 I3 、MAPb 0.75 Sn 0.25 (I 0.4 Br 0.6 ) 3 、FA 0.75 MA 0.35 PbI 3 、MASnBr 3 、FA 0.6 MA 0.4 PbI 3 、FA 0.4 MA 0.6 PbI 3 、FA 0.5 MA 0.5 Pb 0.75 Sn 0.25 I 3 、FA 0.8 MA 0.2 Pb 0.5 Sn 0.5 I3 、FA 0.3 MA 0.7 Pb(I 0.8 Br 0.2 ) 3 、FA 0.1 MA 0.9 Pb(I 0.6 Br 0.4 ) 3 、Cs 0.6 MA 0.4 Pb(I 0.6 Br 0.4 ) 3 、Cs 0.1 MA 0.9 Pb(I 0.6 Br 0.4 ) 3 、Cs 0.1 MA 0.9 PbBr 3 、Cs 0.1 FA 0.2 MA 0.7 Pb(I 0.85 Br 0.15 ) 3 、Cs 0.05 FA 0.80 MA 0.15 Pb(I 0.75 Br 0.25 ) 3 、Cs 0.5 FA 0.4 MA 0.1 Pb(I0.83 Br 0.17 ) 3 , Cs 0.05 FA 0.79 MA 0.16 Pb(I 0.75 Br 0.25 ) 3 , Cs 0.15 FA 0.65 MA 0.2 Pb(I 0.8 Br 0.2 ) 3 , Cs 0.1 FA 0.5 MA 0.4 PbB 3 , Cs 0.15 FA 0.65 MA 0.2 Pb(I 0.8 Br 0.2 ) 3 , Cs 0.05 FA 0.85 MA 0.1 Pb(I 0.755 Br 0.255 ) 3 or Rb 0.05 Cs 0.05 MA 0.05 FA 0.85 Pb(I 0.95 Br 0.05 ) 3 .

[0036] In a further optional embodiment, the thickness of the perovskite layer 3 is 100nm to 3000nm, preferably 100nm to 1000nm, such as 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm and 1000nm, etc. For the perovskite layer 3, its thickness directly affects the photoelectric conversion efficiency of the perovskite solar cell. A thicker perovskite layer 3 can absorb more photons, thereby increasing the short-circuit current, but an overly thick perovskite layer 3 will cause the carrier transmission path to grow, increase the recombination loss, and reduce the open circuit voltage and fill factor. Therefore, in the embodiment of the present invention, the thickness of the perovskite layer 3 is set to 100nm to 1000nm, which ensures the photoelectric conversion efficiency of the perovskite solar cell on the one hand, and minimizes the recombination loss on the other hand.

[0037] For the passivation layer 5, in an optional embodiment, the material of the passivation layer 5 is aniline salt, and the solvent used to prepare the passivation layer 5 is an alcohol solvent, and the thickness of the passivation layer is 0.5 nm to 10 nm, for example, 0.5 nm, 1.5 nm, 3.0 nm, 4.5 nm, 6.0 nm, 7.5 nm, 9.0 nm, 10.0 nm, etc. This is the passivation layer 5 material and thickness commonly used in the prior art, and is also the main reason for the technical problem solved by the present invention. Therefore, the present invention will not go into details about this.

[0038] In an optional embodiment, the provided perovskite solar cell also includes: a modification layer 7 stacked on the outside of the electron transport layer 6; wherein the material of the electron transport layer 6 is one or more of fullerene or fullerene derivatives (such as footballene C60, fullerene derivative PCBM, fullerene derivative ICBA, etc.); the modification layer 7 includes at least one of the following: bathocuproin, lithium fluoride, molybdenum oxide, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline and magnesium fluoride. Specifically, the electron transport layer 6 can enhance the separation effect of electrons and holes, thereby effectively improving the conversion efficiency of the solar cell, while increasing the transmission rate of electrons, reducing the impedance of the current, and increasing the overall current of the perovskite solar cell. The modification layer 7 can serve as an electron blocking layer on the one hand to prevent electrons from flowing back from the perovskite layer to the electrode under light, thereby increasing the open circuit voltage of the device, and on the other hand to reduce the influence of moisture and oxygen on the battery performance, thereby extending the service life of the battery.

[0039] In a further optional embodiment, the thickness of the electron transport layer 6 can be set to 5nm to 50nm, such as 5nm, 10nm, 15nm, 25nm, 35nm, 40nm, 50nm, etc. Under normal circumstances, the greater the thickness of the electron transport layer 6, the lower the electron transport efficiency, but at the same time it can also effectively suppress the phenomenon of electron backflow. Therefore, the thickness of the electron transport layer 6 is set to 5nm to 50nm in the present invention, which can balance the injection rate of holes and electrons, thereby improving the current efficiency and luminescence performance of the perovskite solar cell. In addition, for the thickness of the modified layer 7, in an optional embodiment, it can be 1nm to 20nm, such as 1nm, 5nm, 10nm, 15nm, 20nm, etc.

[0040] Regarding the selection of the material of the electrode 8, in an optional embodiment, the material of the electrode 8 is generally a metal material, which may include one or more of gold, silver, copper and aluminum.

[0041] In a further optional embodiment, the thickness of the electrode 8 can be set to 10 nm~200 nm, for example, 10 nm, 50 nm, 100 nm, 150 nm, 200 nm, etc.

[0042] In summary, the perovskite solar cell provided by the embodiment of the present invention protects the perovskite layer 3 by providing a buffer layer 4 between the perovskite layer 3 and the passivation layer 5, so as to prevent the solvent in the passivation layer 5 from dissolving the methylamine component in the perovskite layer 3. Among them, by setting the material of the buffer layer 4 to a polycyclic aromatic conjugated polymer without a reaction activation site, it is ensured that the buffer layer 4 will not react with the perovskite layer 3 and the passivation layer 5, which not only ensures the repeatability of the perovskite solar cell, but also does not affect the overall performance of the perovskite solar cell.

[0043] The present embodiment provides a method for preparing the above-mentioned perovskite solar cell, which may include the following steps: preparing a hole transport layer 2, a perovskite layer 3, a buffer layer 4, a passivation layer 5, an electron transport layer 6 and an electrode 8 in sequence from the inside to the outside on one side of the thickness direction of the substrate 1; or, preparing a hole transport layer 2, a perovskite layer 3, a buffer layer 4, a passivation layer 5, an electron transport layer 6, a modification layer 7 and an electrode 8 in sequence from the inside to the outside on one side of the thickness direction of the substrate 1.

[0044] The buffer layer 4 is also formed of a polycyclic aromatic conjugated polymer; the substrate can be made of a commonly used ITO glass material. For the preparation steps of the buffer layer 4, in an optional embodiment, as Figure 2 As shown, including:

[0045] Step S201, using chloroform or chlorobenzene as a solvent to dissolve the polycyclic aromatic conjugated polymer to obtain a buffer layer solution;

[0046] Step S202 , coating a buffer layer solution on the perovskite layer 3 to obtain a buffer layer 4 on the perovskite layer 3 .

[0047] It is understandable that not only the polycyclic aromatic conjugated polymer of the buffer layer 4 itself will not react with the perovskite layer 3 and the passivation layer 5, but also the solution of the polycyclic aromatic conjugated polymer dissolved in the buffer layer 4 will not react with the perovskite layer 3 and the passivation layer 5, so as to ensure that the setting of the buffer layer 4 will not affect the overall performance of the perovskite solar cell. Considering the solubility characteristics of the polymer itself, the present invention selects chloroform or chlorobenzene as a solvent to ensure the solubility of the polycyclic aromatic conjugated polymer in the solvent, so as to form a dense and uniform film structure.

[0048] In an optional embodiment, the specific preparation process of the passivation layer 5 can be as follows: Figure 3 As shown, including:

[0049] Step S301, dissolving aniline salt with an alcohol solvent to obtain aniline salt material;

[0050] Step S302 , spin-coating an aniline salt material on the outside of the buffer layer 4 to form a passivation layer 5 .

[0051] The alcohol solvent may be isopropanol which has good solubility in aniline salt. In a further optional embodiment, after the passivation layer 5 is formed, the electron transport layer 6, the modification layer 7 and the electrode 8 may be formed by evaporation.

[0052] In summary, the method for preparing a perovskite solar cell provided by an embodiment of the present invention protects the perovskite layer 3 by setting a buffer layer 4 between the perovskite layer 3 and the passivation layer 5 to prevent the solvent in the passivation layer 5 from dissolving the methylamine component in the perovskite layer 3. Among them, by setting the material of the buffer layer 4 to a polycyclic aromatic conjugated polymer without a reaction activation site, it is ensured that the buffer layer 4 will not react with the perovskite layer 3 and the passivation layer 5, which not only ensures the repeatability of the perovskite solar cell, but also does not affect the overall performance of the perovskite solar cell.

[0053] Example 1

[0054] Step a, using ITO glass as a substrate, spin coating a 5 nm hole transport layer ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid) on one side of the substrate in the thickness direction;

[0055] Step b, using spin coating to prepare a perovskite layer on the outside of the hole transport layer, the component is Cs 0.05 FA 0.85 MA 0.1 Pb(I 0.755 Br 0.255 ) 3 , thickness is 500nm;

[0056] Step c, preparing a buffer layer by spin coating on the outer side of the perovskite layer, wherein the buffer layer component is polyacenaphthene, the solvent is chlorobenzene, and the thickness is 1 nm;

[0057] Step d, preparing a passivation layer by spin coating on the outside of the buffer layer, wherein the passivation layer uses aniline salt material (PDADI), the solvent is isopropanol, and the thickness is 5 nm;

[0058] Step e: on the outside of the passivation layer, an electron transport layer C60 with a thickness of 20 nm, a modification layer BCP with a thickness of 5 nm, and an electrode Ag with a thickness of 100 nm are sequentially deposited.

[0059] Example 2

[0060] Step a, using ITO glass as a substrate, spin coating a 5 nm hole transport layer ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid) on one side of the substrate in the thickness direction;

[0061] Step b, using spin coating to prepare a perovskite layer on the outside of the hole transport layer, the component is Cs 0.05 FA0.85 MA 0.1 Pb(I 0.755 Br 0.255 ) 3 , thickness is 500nm;

[0062] Step c, preparing a buffer layer by spin coating on the outer side of the perovskite layer, wherein the buffer layer component is polyacenaphthene, the solvent is chlorobenzene, and the thickness is 3 nm;

[0063] Step d, preparing a passivation layer by spin coating on the outside of the buffer layer, wherein the passivation layer uses aniline salt material (PDADI), the solvent is isopropanol, and the thickness is 5 nm;

[0064] Step e: on the outside of the passivation layer, an electron transport layer C60 with a thickness of 20 nm, a modification layer BCP with a thickness of 5 nm, and an electrode Ag with a thickness of 100 nm are sequentially deposited.

[0065] Example 3

[0066] Step a, using ITO glass as a substrate, spin coating a 5 nm hole transport layer ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid) on one side of the substrate in the thickness direction;

[0067] Step b, using spin coating to prepare a perovskite layer on the outside of the hole transport layer, the component is Cs 0.05 FA 0.85 MA 0.1 Pb(I 0.755 Br 0.255 ) 3 , thickness is 500nm;

[0068] Step c, preparing a buffer layer by spin coating on the outer side of the perovskite layer, wherein the buffer layer component is polyacenaphthene, the solvent is chlorobenzene, and the thickness is 5 nm;

[0069] Step d, preparing a passivation layer by spin coating on the outside of the buffer layer, wherein the passivation layer uses aniline salt material (PDADI), the solvent is isopropanol, and the thickness is 5 nm;

[0070] Step e: on the outside of the passivation layer, an electron transport layer C60 with a thickness of 20 nm, a modification layer BCP with a thickness of 5 nm, and an electrode Ag with a thickness of 100 nm are sequentially deposited.

[0071] Example 4

[0072] Step a, using ITO glass as a substrate, spin coating a 5 nm hole transport layer ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid) on one side of the substrate in the thickness direction;

[0073] Step b, using spin coating to prepare a perovskite layer on the outside of the hole transport layer, the component is Cs 0.05FA 0.85 MA 0.1 Pb(I 0.755 Br 0.255 ) 3 , thickness is 500nm;

[0074] Step c, preparing a buffer layer by spin coating on the outer side of the perovskite layer, wherein the buffer layer component is polyacenaphthene, the solvent is chlorobenzene, and the thickness is 10 nm;

[0075] Step d, preparing a passivation layer by spin coating on the outside of the buffer layer, wherein the passivation layer uses aniline salt material (PDADI), the solvent is isopropanol, and the thickness is 5 nm;

[0076] Step e: on the outside of the passivation layer, an electron transport layer C60 with a thickness of 20 nm, a modification layer BCP with a thickness of 5 nm, and an electrode Ag with a thickness of 100 nm are sequentially deposited.

[0077] Example 5

[0078] Step a, using ITO glass as a substrate, spin coating a 5 nm hole transport layer ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid) on one side of the substrate in the thickness direction;

[0079] Step b, using spin coating to prepare a perovskite layer on the outside of the hole transport layer, the component is Rb 0.05 Cs 0.05 MA 0.05 FA 0.85 Pb(I 0.95 Br 0.05 ) 3 , thickness is 500nm;

[0080] Step c, preparing a buffer layer by spin coating on the outer side of the perovskite layer, wherein the buffer layer component is polyacenaphthene, the solvent is chlorobenzene, and the thickness is 3 nm;

[0081] Step d, preparing a passivation layer by spin coating on the outside of the buffer layer, wherein the passivation layer uses aniline salt material (PDADI), the solvent is isopropanol, and the thickness is 5 nm;

[0082] Step e: on the outside of the passivation layer, an electron transport layer C60 with a thickness of 20 nm, a modification layer BCP with a thickness of 5 nm, and an electrode Ag with a thickness of 100 nm are sequentially deposited.

[0083] Comparative Example 1

[0084] Step a, using ITO glass as a substrate, spin coating a 5 nm hole transport layer ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid) on one side of the substrate in the thickness direction;

[0085] Step b, using spin coating to prepare a perovskite layer on the outside of the hole transport layer, the component is Cs 0.05 FA 0.85 MA 0.1 Pb(I 0.755 Br 0.255 ) 3 , thickness is 500nm;

[0086] Step c, preparing a passivation layer by spin coating on the outer side of the perovskite layer, wherein the passivation layer uses aniline salt material (PDADI), the solvent is isopropanol, and the thickness is 5 nm;

[0087] Step d: On the outside of the passivation layer, an electron transport layer C60 with a thickness of 20 nm, a modification layer BCP with a thickness of 5 nm, and an electrode Ag with a thickness of 100 nm are sequentially evaporated.

[0088] Comparative Example 2

[0089] Step a, using ITO glass as a substrate, spin coating a 5 nm hole transport layer ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid) on one side of the substrate in the thickness direction;

[0090] Step b, using spin coating to prepare a perovskite layer on the outside of the hole transport layer, the component is Rb 0.05 Cs 0.05 MA 0.05 FA 0.85 Pb(I 0.95 Br 0.05 ) 3 , thickness is 500nm;

[0091] Step c, preparing a passivation layer by spin coating on the outer side of the perovskite layer, wherein the passivation layer uses aniline salt material (PDADI), the solvent is isopropanol, and the thickness is 5 nm;

[0092] Step d: On the outside of the passivation layer, an electron transport layer C60 with a thickness of 20 nm, a modification layer BCP with a thickness of 5 nm, and an electrode Ag with a thickness of 100 nm are sequentially evaporated.

[0093] The perovskite solar cells were prepared through the above multiple embodiments and comparative examples, and the performance of the prepared perovskite solar cells was tested. The results are shown in the following table:

[0094]

[0095] According to the above results, it can be seen that when the thickness of the buffer layer is set to 1nm, the open circuit voltage Voc, short circuit current Jsc, fill factor FF and photoelectric conversion efficiency PCE of the prepared perovskite solar cell are lower than those of Example 2 and Example 3, indicating that the thickness of the buffer layer is too thin and cannot fully block the solvent penetration in the passivation layer from dissolving the perovskite layer, so the performance is slightly weakened. However, compared with Comparative Example 1, the open circuit voltage Voc, short circuit current Jsc, fill factor FF and photoelectric conversion efficiency PCE are all improved, indicating that the setting of the buffer layer blocks the solvent penetration in the passivation layer from dissolving the perovskite layer to a certain extent, but because of the small thickness, the blocking effect is poor, but there is still a significant improvement in performance. Similarly, the performance comparison between Example 5 and Comparative Example 2 can also illustrate that the buffer layer set in the embodiment of the present invention can effectively block the solvent penetration in the passivation layer from dissolving the perovskite layer, thereby improving the overall performance of the perovskite solar cell.

[0096] The introduction provided in the above steps is only used to help understand the structure, method and core idea of ​​the present invention. For ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also belong to the scope of protection of the claims of the present invention.

Claims

1. A perovskite solar cell, comprising a substrate (1), a hole transport layer (2), a perovskite layer (3), a passivation layer (5), an electron transport layer (6) and an electrode (8) stacked from bottom to top, characterized in that: It also includes a buffer layer (4) arranged between the perovskite layer (3) and the passivation layer (5); Wherein, the buffer layer (4) is formed by a polycyclic aromatic conjugated polymer.

2. The perovskite solar cell according to claim 1, characterized in that The buffer layer (4) has a thickness of 1 nm to 10 nm.

3. The perovskite solar cell according to claim 1, characterized in that The polycyclic aromatic conjugated polymer includes one or more of polyacenaphthene, polypyridine, polypyrrole and polypyrimidine.

4. The perovskite solar cell according to claim 1, characterized in that: The material of the perovskite layer (3) is a perovskite material containing methylamine ions; The material of the passivation layer (5) is aniline salt, and the solvent used to prepare the passivation layer (5) is an alcohol solvent.

5. The perovskite solar cell according to claim 1 or 4, characterized in that: The general chemical formula of the perovskite material of the perovskite layer (3) is ABX3, wherein the A ions include CH3NH3 + , or CH3NH3 + With (HC(NH)2)2 + , Cs + and Rb + At least one combination of the B ions including Pb 2+ Sn 2+ and Sr 2+ At least one of the X ions includes Br - ,I - and Cl - At least one of; and / or, The thickness of the perovskite layer (3) is 100 nm to 1000 nm; and / or, The thickness of the passivation layer (5) is 0.5 nm to 10 nm.

6. The perovskite solar cell according to claim 1, characterized in that: The material of the hole transport layer (2) is a self-assembled monolayer material containing a phosphate group, including one or more of [2-(9H-carbazole-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid and [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid; and / or, The material of the electron transport layer (6) is one or more of fullerene or fullerene derivatives.

7. The perovskite solar cell according to claim 1 or 6, characterized in that: The thickness of the hole transport layer (2) is 0.5 nm to 10 nm; and / or, The thickness of the electron transport layer (6) is 5 nm to 50 nm.

8. The perovskite solar cell according to claim 6, characterized in that: Also includes: A modification layer (7) disposed between the electron transport layer (6) and the electrode (8); The material of the modification layer (7) includes at least one of bathocuproin, lithium fluoride, molybdenum oxide, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline and magnesium fluoride, and / or the thickness of the modification layer (7) is 1 nm to 20 nm.

9. A method for preparing a perovskite solar cell according to any one of claims 1 to 8, characterized in that: include: On one side of the substrate (1) in the thickness direction, a hole transport layer (2), a perovskite layer (3), a buffer layer (4), a passivation layer (5), an electron transport layer (6), and an electrode (8) are sequentially prepared from the inside to the outside; or, A hole transport layer (2), a perovskite layer (3), a buffer layer (4), a passivation layer (5), an electron transport layer (6), a modification layer (7), and an electrode (8) are sequentially prepared from the inside to the outside on one side of the substrate (1) in the thickness direction.

10. The preparation method according to claim 9, characterized in that: The steps of preparing the buffer layer (4) include: Using chloroform or chlorobenzene as a solvent to dissolve the polycyclic aromatic conjugated polymer to obtain a buffer layer solution; The buffer layer solution is coated on the perovskite layer (3) to obtain the buffer layer (4) on the perovskite layer (3).

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