Perovskite solar cell

Abstract

The utility model discloses a perovskite solar cell, the perovskite solar cell comprises a perovskite absorption layer, an electron transport layer, an interface cascade layer and an inorganic buffer layer which are stacked in sequence, and the interface cascade layer comprises a titanium tetrafluoride layer or a lead fluoride layer. According to the perovskite solar cell provided by the invention, the interface cascade layer is arranged between the electron transmission layer and the inorganic buffer layer, so that the interface contact quality between the electron transmission layer and the inorganic buffer layer can be improved, the non-radiative recombination loss of the interface is reduced, the open-circuit voltage and the filling factor of the perovskite solar cell are improved, and the performance of the perovskite solar cell is improved. And the effect of blocking water and oxygen from invading can be achieved, and the photoelectric conversion efficiency and the stability of the perovskite solar cell are improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of solar cells, and more specifically, relates to a perovskite solar cell. Background Art

[0002] With the increasing energy consumption in China and the decreasing reserves of fossil energy, accelerating the development and utilization of energy is of top priority. In the new new energy technology industry, the photovoltaic cell industry occupies a very large proportion.

[0003] Solar energy has always been one of the clean energies that people often talk about, and solar cells that utilize solar energy are also highly anticipated. From the initial small area and low photoelectric conversion efficiency to the current large area and high photoelectric conversion efficiency; from the initial application only in calculators and flashlights to today's outdoor power stations and photovoltaic curtain walls; solar cells have been continuously concerned. How to prepare solar cells with low cost and high photoelectric conversion efficiency has become an enduring hot topic of this era. Solar cells have evolved from the initial crystalline silicon cells to thin-film cells, Topcon cells, and so on. There are various types of solar cells now. Among them, perovskite solar cells, as a newly emerging new structure thin-film cell in recent years, compared with traditional crystalline silicon cells, have the advantages of low price and higher theoretical photoelectric conversion efficiency; compared with traditional cadmium telluride thin-film cells, they have the advantages of non-toxic and harmless materials, adjustable energy bands, more extensive materials, and higher photoelectric conversion efficiency. Therefore, the development of perovskite solar cells has become a major trend in this era. Countless investors and R & D personnel have been involved, which has promoted the perovskite solar cells to charge forward at an extremely rapid momentum.

[0004] However, in the current perovskite solar cell system, the material for electron transport is usually an organic material, which has poor weather resistance, and the deposition and processing route is complex in large-scale production. The cost of the pure organic electron transport layer is high, and it is not suitable for commercial production. The interface contact quality between the organic electron transport layer and the inorganic buffer layer is usually poor, and the density of defect states is large, resulting in large carrier non-radiative recombination losses. This makes the decomposition of perovskite solar cells mainly start from the interface, affecting the photoelectric conversion efficiency and stability of perovskite solar cells. Summary of the Utility Model

[0005] The present utility model aims to solve at least one of the technical problems in the related art to some extent. For this purpose, an object of the present utility model is to provide a perovskite solar cell. The perovskite solar cell provided by the present application can improve the interfacial contact quality between the electron transport layer and the inorganic buffer layer by providing an interfacial cascade layer therebetween, so as to reduce the interfacial non-radiative recombination loss, improve the open-circuit voltage and fill factor of the perovskite solar cell, and can play a role in blocking the intrusion of water and oxygen, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0006] The present utility model provides a perovskite solar cell. According to an embodiment of the present utility model, the perovskite solar cell includes a perovskite absorption layer, an electron transport layer, an interfacial cascade layer, and an inorganic buffer layer which are sequentially stacked, wherein the interfacial cascade layer includes a titanium tetrafluoride layer or a lead fluoride layer.

[0007] For the perovskite solar cell according to the above embodiment of the present utility model, by providing an interfacial cascade layer between the electron transport layer and the inorganic buffer layer and selecting an inorganic fluoride layer such as titanium tetrafluoride or lead fluoride as the interfacial cascade layer, the inorganic fluoride layer can passivate the deep-level defects of the electron transport layer, effectively reduce the interfacial defect state density on the electron transport layer without significantly reducing the current, reduce the carrier loss caused by interfacial non-radiative recombination, and can significantly increase the open-circuit voltage of the perovskite solar cell, thereby improving the photoelectric conversion efficiency of the battery. The interfacial cascade layer may refer to a film layer provided between two film layers to increase the energy level matching degree between the energy levels of the two side film layers (such as the electron transport layer and the inorganic buffer layer), and generally can promote the transport of carriers between the film layers. The inorganic fluoride layer also has good barrier performance and can prevent water vapor and other environmental factors from invading the battery interior, thereby improving the stability of the battery. In addition, inorganic fluoride materials are usually lower in cost than organic materials and have a simple processing process, which is beneficial to reducing the overall production cost of the solar cell. Therefore, the perovskite solar cell provided by the present application has high photoelectric conversion efficiency and stability.

[0008] In addition, the perovskite solar cell according to the above embodiment of the present utility model may further have the following additional technical features:

[0009] In some embodiments of the present utility model, the thickness of the interfacial cascade layer is 1 to 3 nm. Thus, it is possible to reduce the non-radiative recombination of electrons and holes at the interface, help to retain more photo-generated carriers, and thereby improve the photoelectric conversion efficiency of the battery.

[0010] In some embodiments of the present utility model, the thickness of the interface cascade layer is 1.5 - 2.5 nm. Thus, it is possible to reduce the non-radiative recombination of electrons and holes at the interface, contribute to maintaining more photo-generated carriers, and thereby improve the photoelectric conversion efficiency of the battery.

[0011] In some embodiments of the present utility model, the thickness of the electron transport layer is 4 - 40 nm, and the electron transport layer is layer C 60 layer. Thus, it is possible to effectively collect and transport electrons, reduce the loss of electrons during the transport process, contribute to reducing the non-radiative recombination of electrons and holes at the interface, and thereby improve the open-circuit voltage of the battery.

[0012] In some embodiments of the present utility model, the inorganic buffer layer includes an IWO buffer layer and an ITO buffer layer which are stacked in sequence. The IWO buffer layer is disposed on the side of the interface cascade layer away from the electron transport layer, and the ITO buffer layer is disposed on the side of the IWO buffer layer away from the interface cascade layer. Thus, better interface passivation and charge transport effects can be achieved.

[0013] In some embodiments of the present utility model, the thickness of the IWO buffer layer is 10 - 120 nm. Thus, it is possible to improve the resistance of the battery to water, oxygen, and other environmental factors, and extend the service life of the battery.

[0014] In some embodiments of the present utility model, the thickness of the ITO buffer layer is 30 - 60 nm. Thus, it is helpful to form a good interface combination with the IWO layer and improve the overall structural stability of the battery.

[0015] In some embodiments of the present utility model, the perovskite solar cell further includes a bottom electrode layer, a hole transport layer, and a back electrode layer. The hole transport layer is disposed between the bottom electrode layer and the perovskite absorption layer, and the back electrode layer is disposed on the side of the inorganic buffer layer away from the interface cascade layer. Thus, the perovskite solar cell provided by the present application has high photoelectric conversion efficiency and stability.

[0016] In some embodiments of the present utility model, the thickness of the hole transport layer is 10 - 20 nm, and the material of the hole transport layer includes any one of NiO x , Cu2O, and MoO x . Thus, it is possible to effectively collect and transport holes, reduce the recombination loss of holes during the transport process, and also reduce the non-radiative recombination of electrons and holes at the interface, and thereby improve the open-circuit voltage of the battery.

[0017] In some embodiments of the present utility model, the thickness of the back electrode is 30-110 nm, and the material of the back electrode includes any one of Cu, Al, Ag, Ni, Co, Au, Mo, and Cr. Thus, it is possible to provide sufficient electron transport paths and effectively collect the current generated by the active layer.

[0018] Additional aspects and advantages of the present utility model will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present utility model will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0020] Figure 1 Shows the structure diagram of a perovskite solar cell according to an embodiment of the present application.

[0021] Reference Numerals in the Drawings:

[0022] Perovskite solar cell 100, bottom electrode layer 10, hole transport layer 20, perovskite absorption layer 30, electron transport layer 40, interfacial cascade layer 50, inorganic buffer layer 60, back electrode layer 70. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] Embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below are exemplary and are intended to explain the present utility model and should not be construed as limiting the present utility model.

[0024] The present utility model provides a perovskite solar cell 100. According to an embodiment of the present utility model, the perovskite solar cell 100 includes a perovskite absorption layer 30, an electron transport layer 40, an interfacial cascade layer 50, and an inorganic buffer layer 60 that are sequentially stacked. Among them, the interfacial cascade layer 50 includes a titanium tetrafluoride layer or a lead fluoride layer.

[0025] For the perovskite solar cell 100 according to the above embodiments of the present invention, by providing an interfacial cascade layer 50 between the electron transport layer 40 and the inorganic buffer layer 60, and selecting an inorganic fluoride layer such as titanium tetrafluoride or lead fluoride as the interfacial cascade layer 50, the inorganic fluoride layer can passivate the deep-level defects of the electron transport layer 40. Without significantly reducing the current, it effectively reduces the interfacial defect state density on the electron transport layer 40, reduces the carrier loss caused by interfacial non-radiative recombination, and can significantly improve the open-circuit voltage of the perovskite solar cell 100, thereby improving the photoelectric conversion efficiency of the cell. The inorganic fluoride layer also has good barrier properties, which can prevent water vapor and other environmental factors from invading the interior of the cell, thus improving the stability of the cell. In addition, inorganic fluoride materials are usually lower in cost than organic materials, and the processing technology is simple, which is beneficial to reducing the overall production cost of solar cells. Therefore, the perovskite solar cell 100 provided by this application has high photoelectric conversion efficiency and stability.

[0026] Further, referring to Figure 1 , the perovskite solar cell further includes a bottom electrode layer 10, a hole transport layer 20, and a back electrode layer 70. The hole transport layer 20 is disposed between the bottom electrode layer 10 and the perovskite absorption layer 30, and the back electrode layer 70 is disposed on a side of the inorganic buffer layer 60 away from the interfacial cascade layer 50.

[0027] It should be noted that the interfacial cascade layer 50 may refer to a film layer disposed between two film layers to increase the energy level matching degree between the energy levels of the two side film layers (such as the electron transport layer 40 and the inorganic buffer layer 60), thereby promoting the transport of carriers between the film layers.

[0028] According to some specific embodiments of the present invention, the material of the bottom electrode layer 10 includes any one of fluorine-doped tin oxide (FTO) and indium tin oxide (ITO). The bottom electrode layer 10 can not only serve as the substrate of the perovskite solar cell 100 and be responsible for transmitting and collecting current. Using FTO or ITO as the material of the bottom electrode layer 10, where both FTO and ITO have high transparency, allowing as much sunlight as possible to penetrate into the active layer of the cell. FTO and ITO also have high electrical conductivity and can effectively transmit and collect the photo-generated current.

[0029] Optionally, during the preparation of the perovskite solar cell 100, first, the bottom electrode is ultrasonically cleaned with a glass cleaning agent and deionized water in sequence, dried, and the conductive glass is treated with ultraviolet-ozone. Thus, a clean surface can be provided for the subsequent coating process.

[0030] According to some specific embodiments of the present invention, the thickness of the hole transport layer 20 is 10 - 20 nm. For example, it can be 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, etc. By forming the hole transport layer 20 on one side of the bottom electrode layer 10, wherein the hole transport layer 20 can transport photo-generated holes from the perovskite absorption layer 30 to the anode. By limiting the thickness of the hole transport layer 20 within the above range, holes can be effectively collected and transported, reducing the recombination loss of holes during the transport process, and also reducing the non-radiative recombination of electrons and holes at the interface, thereby improving the open-circuit voltage of the battery.

[0031] Furthermore, the material of the hole transport layer 20 includes but is not limited to NiO x , Cu2O, and MoO x and any one of them.

[0032] Optionally, the hole transport layer 20 is fabricated by processes such as magnetron sputtering, vacuum evaporation, solution method, atomic layer deposition (ALD) method, reactive plasma deposition (RPD) method, etc.

[0033] According to some specific embodiments of the present invention, a perovskite absorption layer 30 is formed on the side of the hole transport layer 20 away from the bottom electrode layer 10. The perovskite absorption layer 30 can efficiently absorb sunlight, thereby generating a large number of photo-generated carriers, which helps to improve the photoelectric conversion efficiency of the battery.

[0034] Optionally, the perovskite absorption layer 30 is fabricated by processes such as blade coating, spin coating, etc.

[0035] According to some specific embodiments of the present invention, the thickness of the electron transport layer 40 is 4 - 40 nm. For example, it can be 4 nm, 10 nm, 20 nm, 40 nm, etc. By forming the electron transport layer 40 on the side of the perovskite absorption layer 30 away from the hole transport layer 20, the electron transport layer 40 can transport photo-generated electrons from the perovskite layer to the cathode of the battery. Further limiting the thickness of the electron transport layer 40 within the above range can effectively collect and transport electrons, reduce the loss of electrons during the transport process, and help reduce the non-radiative recombination of electrons and holes at the interface, thereby improving the open-circuit voltage of the battery.

[0036] Optionally, the electron transport layer 40 is a C 60 layer. The C 60 molecule has a high electron affinity and can effectively accept electrons from the perovskite layer. The C 60 layer can modify the interface between the perovskite layer and the electron transport layer, reduce interface defects, and improve the battery performance.

[0037] It should be noted that the C 60The material is a carbon atom cluster composed of 60 carbon atoms, forming a 32-sided polyhedron like a football, including 20 hexagons and 12 pentagons.

[0038] Optionally, the electron transport layer 40 is fabricated by processes such as vacuum evaporation and solution method.

[0039] Optionally, the C 60 layer is a C layer deposited by vacuum evaporation, 60 the vacuum degree of the vacuum evaporation is lower than 8.0×10 -4 Pa, the temperature of the vacuum evaporation is 400 - 550 °C, and the deposition rate of the vacuum evaporation is

[0040] According to some specific embodiments of the present invention, the interface cascade layer 50 includes a titanium tetrafluoride layer. By providing a titanium tetrafluoride layer on the side of the electron transport layer 40 away from the perovskite absorption layer 30, the titanium tetrafluoride layer can form an island structure on the surface of the electron transport layer 40, passivate the dangling bonds or unsaturated sites existing on the surface of the electron transport layer 40, reduce interface states, and further reduce the non-radiative recombination of electrons and holes at the interface, which helps to retain more photo-generated carriers, thereby improving the photoelectric conversion efficiency of the battery. Thus, using the titanium tetrafluoride layer as the interface cascade layer 50 can effectively reduce the density of interface defect states on the electron transport layer 40, improve the interface contact quality between the electron transport layer 40 and the inorganic buffer layer 60, and improve the stability of the battery, which is beneficial to large-scale commercial production.

[0041] According to some specific embodiments of the present invention, the thickness of the interface cascade layer 50 is 1 - 3 nm. For example, it can be 1 nm, 2 nm, 3 nm, etc. By limiting the thickness of the interface cascade layer 50 within the above range, an island structure can be formed on the surface of the electron transport layer 40, which can effectively passivate the dangling bonds or unsaturated sites existing on the surface of the electron transport layer 40, reduce interface states, and further reduce the non-radiative recombination of electrons and holes at the interface, which helps to retain more photo-generated carriers, thereby improving the photoelectric conversion efficiency of the battery. Further, the thickness of the interface cascade layer 50 is 1.5 - 2.5 nm.

[0042] Optionally, the interface cascade layer 50 is fabricated by processes such as vacuum evaporation and solution method.

[0043] Optionally, the titanium tetrafluoride layer is a titanium tetrafluoride layer deposited by vacuum evaporation, the vacuum degree of the vacuum evaporation is 3.5×10 -4 Pa, the temperature of the vacuum evaporation is 100 - 200 °C, and the deposition rate of the vacuum evaporation is

[0044] According to some specific embodiments of the present invention, the inorganic buffer layer 60 includes an IWO buffer layer and an ITO buffer layer which are stacked in sequence. The IWO buffer layer is disposed on the side of the interface cascade layer 50 away from the electron transport layer 40, and the ITO buffer layer is disposed on the side of the IWO buffer layer away from the interface cascade layer 50. By providing two buffer layers of IWO and ITO, better interface passivation and charge transport effects can be achieved. The IWO layer has a high electron mobility, which can promote the effective transport of electrons. Moreover, due to its good chemical stability, the IWO layer can improve the battery's resistance to environmental factors and extend the battery life. The ITO buffer layer is disposed outside the IWO layer and can act as a protective layer to prevent the influence of external environmental factors on the IWO layer and the internal structure of the battery, which is beneficial to improving the stability of the perovskite solar cell 100.

[0045] According to some specific embodiments of the present invention, the thickness of the IWO buffer layer is 10 - 120 nm. For example, it can be 10 nm, 30 nm, 50 nm, 80 nm, 100 nm, 120 nm, etc. By limiting the thickness of the IWO buffer layer within the above range, it is beneficial to maintain a high electron transport efficiency, thereby improving the overall performance of the battery. Moreover, it can also improve the battery's resistance to water, oxygen, and other environmental factors and extend the battery's service life.

[0046] According to some specific embodiments of the present invention, the thickness of the ITO buffer layer is 30 - 60 nm. For example, it can be 30 nm, 40 nm, 50 nm, 60 nm, etc. By limiting the thickness of the ITO buffer layer within the above range, it helps to form a good interface bonding with the IWO layer and improve the overall structural stability of the battery.

[0047] Optionally, the transparent conductive oxide layer 70 is fabricated by processes such as reactive plasma deposition and magnetron sputtering.

[0048] According to some specific embodiments of the present invention, the thickness of the back electrode layer 70 is 30 - 110 nm. For example, it can be 30 nm, 50 nm, 80 nm, 100 nm, 110 nm, etc. The back electrode layer 70 is formed on the side of the inorganic buffer layer 60 away from the electron transport layer 40. The back electrode layer 70 is used to collect current and transmit it to the outside of the battery. Further limiting the thickness of the back electrode layer 70 within the above range can provide sufficient electron transport paths and effectively collect the current generated by the active layer.

[0049] Optionally, the material of the back electrode includes, but is not limited to, any one of Cu, Al, Ag, Ni, Co, Au, Mo, and Cr.

[0050] Optionally, the back electrode layer 70 is fabricated by processes such as evaporation and magnetron sputtering.

[0051] Method for fabricating the perovskite solar cell 100 according to an embodiment of the present invention:

[0052] S1. Prepare a hole transport layer 20 on one side of the bottom electrode layer 10;

[0053] S2. Prepare a perovskite absorption layer 30 on the side of the hole transport layer 20 away from the bottom electrode layer 10;

[0054] S3. Prepare an electron transport layer 40 on the side of the perovskite absorption layer 30 away from the hole transport layer 20;

[0055] S4. Prepare an interface cascade layer 50 on the side of the electron transport layer 40 away from the perovskite absorption layer 30;

[0056] S5. Prepare an inorganic buffer layer 60 on the side of the interface cascade layer 50 away from the electron transport layer 40;

[0057] S6. Prepare a back electrode layer 70 on the side of the inorganic buffer layer 60 away from the interface cascade layer 50.

[0058] According to the method of the embodiment of the present invention, by preparing and forming an interface cascade layer 50 between the electron transport layer 40 and the inorganic buffer layer 60, and selecting an inorganic fluoride layer such as titanium tetrafluoride or lead fluoride as the interface cascade layer 50, the inorganic fluoride layer can passivate the deep-level defects of the electron transport layer 40. Without significantly reducing the current, it effectively reduces the density of interface defect states on the electron transport layer 40, reduces the carrier loss caused by interface non-radiative recombination, and can significantly increase the open-circuit voltage of the perovskite solar cell 100, thereby improving the photoelectric conversion efficiency of the battery. The interface cascade layer 50 also has good barrier properties, which can prevent water vapor and other environmental factors from invading the battery interior, thus improving the stability of the battery. In addition, inorganic fluoride materials are usually lower in cost than organic materials, and the processing process is simple, which is beneficial to reducing the overall production cost of the solar cell. Therefore, the perovskite solar cell 100 provided by this application has high photoelectric conversion efficiency and stability.

[0059] The following will explain the solution of the present disclosure in conjunction with embodiments. Those skilled in the art will understand that the following embodiments are only used to illustrate the present disclosure and should not be construed as limiting the scope of the present disclosure. For those not specified in the embodiments regarding specific technologies or conditions, they shall be carried out according to the technologies or conditions described in the literature in this field or according to the product specifications. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial procurement.

[0060] Example 1

[0061] 1. The FTO conductive glass was ultrasonically cleaned successively with a glass cleaning agent and deionized water, and then placed in an oven at 100 °C for sufficient drying. This process was repeated three times. The FTO conductive glass was subjected to ultraviolet-ozone treatment for 30 min. After that, it was put into a magnetron sputtering device. When the vacuum was lower than 1×10 -3 Pa, the flow rates of high-purity argon and argon-oxygen mixture were set, and magnetron sputtering was carried out on the FTO bottom electrode layer using a radio frequency power supply to obtain a nickel oxide hole transport layer with a thickness of 15 nm;

[0062] 2. An appropriate amount of perovskite precursor solution was spin-coated on the surface of the nickel oxide hole transport layer obtained in step 1. Among them, the perovskite precursor solution was Cs 0.1 FA 0.9 PbI3 (with a concentration of 1.1 M), and the spin-coated thickness was 500 nm. Then, the excess solvent was blown away with nitrogen, and then it was placed on a heating table and annealed at 70 °C for 2 min and then at 110 °C for 40 min to obtain a perovskite absorption layer.

[0063] 3. Using the vacuum evaporation method, under the condition of a vacuum degree of 3.5×10 -4 Pa, C 60 was placed in a crucible and heated to 500 °C to make the deposition rate On the surface of the perovskite absorption layer obtained in step 2, a C 60 layer with a thickness of 20 nm was deposited to obtain a C 60 electron transport layer.

[0064] 4. Using the vacuum evaporation method, under the condition of a vacuum degree of 3.5×10 -4 Pa, titanium tetrafluoride was placed in a crucible and heated to 150 °C to make the deposition rate On the surface of the C 60 electron transport layer obtained in step 3, a titanium tetrafluoride layer with a thickness of 2 nm was deposited by thermal evaporation to obtain a titanium tetrafluoride interfacial cascade layer.

[0065] 5. Using a reaction plasma deposition (RPD) device, an IWO buffer layer with a thickness of 100 nm was deposited on the surface of the titanium tetrafluoride interfacial cascade layer obtained in step 4.

[0066] 6. Using the magnetron sputtering method, an ITO buffer layer with a thickness of 50 nm and a Cu back electrode layer with a thickness of 90 nm were successively deposited on the IWO buffer layer obtained in step 5, thus obtaining a perovskite solar cell.

[0067] Example 2

[0068] The difference between Example 2 and Example 1 is that:

[0069] The titanium tetrafluoride layer in Step 4 is 1 nm, and the rest is the same as in Example 1.

[0070] Example 3

[0071] The difference between Example 3 and Example 1 is that:

[0072] The titanium tetrafluoride layer in Step 4 is 3 nm, and the rest is the same as in Example 1.

[0073] Comparative Example 1

[0074] In Comparative Example 1, except for deleting Step 4 in Example 1, the rest is the same as in Example 1.

[0075] Performance Test

[0076] Under the same conditions, the photoelectric conversion efficiency and stability of the perovskite solar cells obtained in Examples 1-3 and Comparative Example 1 were tested. The specific test methods are as follows:

[0077] (1) Photoelectric conversion efficiency (PCE) test: Test the photoelectric conversion efficiency of the perovskite solar cell during the aging process. Specifically, the effective area of the cell is 1 cm 2 . The JV curves were all measured under standard sunlight of AM 1.5G, and the irradiance provided by the solar simulator was 1000 W / m 2 .

[0078] Photoelectric conversion efficiency = (open circuit voltage × short circuit current × fill factor) / cell area × light intensity × 100%.

[0079] (2) Stability test: Aging was carried out under the conditions of light stability (maximum output power under simulated sunlight) and high humidity and high temperature stability (85°C, 85% RH), and the photoelectric conversion efficiency of the perovskite battery was tested. The decay rate of the photoelectric conversion efficiency of the perovskite battery with an aging time of 1000 h was statistically analyzed.

[0080] The test results are shown in Table 1, where Voc represents the open circuit voltage, Jsc represents the short circuit current density, FF represents the fill factor, Rs represents the series resistance, Rsh represents the parallel resistance, and the decay rate represents the decay rate of the device efficiency after the stability test.

[0081] Table 1

[0082]

[0083] As can be seen from Table 1, compared with Comparative Example 1, the perovskite solar cells of Examples 1-3 can effectively reduce the density of interfacial defect states on the electron transport layer, improve the interfacial contact quality between the electron transport layer and the inorganic buffer layer, and reduce the carrier loss caused by interfacial non-radiative recombination by preparing an interfacial cascade layer between the electron transport layer and the inorganic buffer layer and using titanium tetrafluoride or lead fluoride as the interfacial cascade layer, without significantly reducing the current, thereby effectively improving the open-circuit voltage of the battery and thus enhancing the photoelectric conversion efficiency of the battery. Moreover, under the action of titanium tetrafluoride or lead fluoride, the barrier ability of the electron transport layer against water vapor intrusion can also be improved, preventing water vapor and other environmental factors from invading the interior of the battery, thereby improving the stability and service life of the battery.

[0084] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", "some implementation manners" or "some examples", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0085] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A perovskite solar cell, characterized in that: The invention comprises a perovskite absorption layer, an electron transport layer, an interface cascade layer and an inorganic buffer layer which are stacked in sequence, wherein the interface cascade layer comprises a titanium tetrafluoride layer or a lead fluoride layer.

2. The perovskite solar cell according to claim 1, characterized in that The thickness of the interface cascade layer is 1-3 nm.

3. The perovskite solar cell according to claim 2, characterized in that: The thickness of the interface cascade layer is 1.5-2.5 nm.

4. The perovskite solar cell according to any one of claims 1 to 3, characterized in that: The thickness of the electron transport layer is 4 to 40 nm. 60 layer.

5. The perovskite solar cell according to any one of claims 1 to 3, characterized in that: The inorganic buffer layer comprises an IWO buffer layer and an ITO buffer layer which are stacked in sequence. The IWO buffer layer is arranged on a side of the interface cascade layer away from the electron transport layer, and the ITO buffer layer is arranged on a side of the IWO buffer layer away from the interface cascade layer.

6. The perovskite solar cell according to claim 5, characterized in that: The thickness of the IWO buffer layer is 10-120 nm.

7. The perovskite solar cell according to claim 5, characterized in that: The thickness of the ITO buffer layer is 30-60 nm.

8. The perovskite solar cell according to any one of claims 1 to 3, characterized in that: The perovskite solar cell further comprises a bottom electrode layer, a hole transport layer and a back electrode layer, wherein the hole transport layer is arranged between the bottom electrode layer and the perovskite absorption layer, and the back electrode layer is arranged on a side of the inorganic buffer layer away from the interface cascade layer.

9. The perovskite solar cell according to claim 8, characterized in that: The thickness of the hole transport layer is 10-20 nm, and the material of the hole transport layer includes NiO x , Cu2O and MoO x Any one of .

10. The perovskite solar cell according to claim 8, characterized in that: The thickness of the back electrode is 30-110 nm, and the material of the back electrode includes any one of Cu, Al, Ag, Ni, Co, Au, Mo and Cr.

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