Solar cell and preparation method thereof, photovoltaic module, system, power utilization device and power generation device

Abstract

The invention relates to a solar cell and a preparation method thereof, a photovoltaic module, a system, a power utilization device and a power generation device. The solar cell comprises a first electrode layer, a first light absorption layer, a first hole transport layer and a second electrode layer which are arranged in a stacked mode. And the component of the first hole transport layer comprises P-type doped SnO2. The solar cell has high photoelectric property stability.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and in particular to a solar cell and a preparation method thereof, a photovoltaic module, a system, an electrical device and a power generation device. Background Art

[0002] Solar cells (also known as photovoltaic cells) are devices that convert light energy directly into electricity through the photoelectric or photochemical effects. In recent years, as global energy shortages have become increasingly prominent, solar cells have garnered increasing attention as an ideal renewable energy source. However, the photoelectric performance and stability of current solar cells need to be improved. Summary of the Invention

[0003] Based on this, the present application aims to provide a solar cell with high photoelectric performance stability and its preparation method, photovoltaic module, system, power-consuming device and power generation device.

[0004] A first aspect of the present application provides a solar cell comprising a stacked first electrode layer, a first light absorbing layer, a first hole transport layer, and a second electrode layer; the first hole transport layer comprises P-type doped SnO2.

[0005] Without wishing to be bound by any theory, the hole transport layer employed in this application comprises P-type doped SnO2. Since P-type doped SnO2 is entirely stable tetravalent tin, with no unstable monovalent or divalent tin, it exhibits superior stability compared to organic hole transport layers and SnOx (x < 2) hole transport layers. This significant advantage in stability allows the aforementioned solar cell to exhibit excellent photoelectric performance stability. The solar cell may comprise a metal composite layer, which also exhibits excellent stability.

[0006] In any embodiment of the present application, the P-type doped SnO2 includes SnO2 doped with at least one doping element of Ga, Sb, Mg, Al and In.

[0007] In any embodiment of the present application, the molar content of the doping element in the first hole transport layer is 2% to 30%.

[0008] In any embodiment of the present application, the thickness of the first hole transport layer is 10 nm to 50 nm.

[0009] In any embodiment of the present application, the solar cell further includes a composite layer and a second light absorption layer sequentially stacked between the first hole transport layer and the second electrode layer.

[0010] In any embodiment of the present application, components of the composite layer include at least one of a metal material and a transparent conductive oxide.

[0011] In any embodiment of the present application, the thickness of the composite layer is 0.5 nm to 3 nm.

[0012] In any embodiment of the present application, the solar cell further includes a second electron transport layer disposed between the composite layer and the second light absorbing layer, and a component of the second electron transport layer includes N-type SnO 2 .

[0013] In any embodiment of the present application, the solar cell further includes a second electron transport layer and a second light absorption layer stacked sequentially between the first hole transport layer and the second electrode layer, the second electron transport layer is in contact with the first hole transport layer, and the component of the second electron transport layer includes N-type SnO2.

[0014] In any embodiment of the present application, the N-type SnO 2 includes at least one of undoped SnO 2 and fluorine-doped SnO 2 .

[0015] In any embodiment of the present application, the thickness of the second electron transport layer is 10 nm to 50 nm.

[0016] In any embodiment of the present application, the first light absorbing layer and the second light absorbing layer are each independently a perovskite light absorbing layer.

[0017] In any embodiment of the present application, the first light absorbing layer is a narrow-bandgap perovskite light absorbing layer, the second light absorbing layer is a wide-bandgap perovskite light absorbing layer, and the second electrode layer is a transparent electrode.

[0018] The second aspect of the present application provides a method for preparing the solar cell according to the first aspect of the present application, comprising the following steps:

[0019] The first electrode layer, the first light absorbing layer, the first hole transport layer and the second electrode layer are stacked and formed.

[0020] In any embodiment of the present application, the preparation method comprises the following steps:

[0021] The first electrode layer, the first light absorbing layer, the first hole transport layer, the composite layer, the second light absorbing layer and the second electrode layer are stacked and formed.

[0022] In any embodiment of the present application, the preparation method comprises the following steps:

[0023] The first electrode layer, the first light absorbing layer, the first hole transport layer, the second electron transport layer, the second light absorbing layer and the second electrode layer are stacked, the second electron transport layer is in contact with the first hole transport layer, and the component of the second electron transport layer includes N-type SnO2.

[0024] The third aspect of the present application provides a photovoltaic assembly, comprising the solar cell provided in the first aspect of the present application.

[0025] A fourth aspect of the present application provides a photovoltaic system, comprising the photovoltaic assembly provided by the third aspect of the present application.

[0026] The fifth aspect of the present application provides an electrical device comprising at least one selected from the solar cell provided in the first aspect of the present application and the photovoltaic module provided in the third aspect of the present application.

[0027] The sixth aspect of the present application provides a power generation device, comprising at least one selected from the solar cell provided in the first aspect of the present application and the photovoltaic module provided in the third aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of a solar cell according to one embodiment of the present application;

[0029] Figure 2 is a schematic diagram of a solar cell according to another embodiment of the present application;

[0030] Figure 3 Schematic diagram of an electrical device using a solar cell as a power source according to one embodiment of the present application.

[0031] Description of reference numerals:

[0032] 1. Solar cell; 11. First electrode layer; 12. First electron transport layer; 13. First perovskite light absorbing layer; 14. First hole transport layer; 15. Recombination layer; 16. Second electron transport layer; 17. Second perovskite light absorbing layer; 18. Second hole transport layer; 19. Second electrode layer;

[0033] 2. Electrical equipment. DETAILED DESCRIPTION

[0034] The following detailed description of the embodiments of the present application is appropriately referred to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially identical structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0035] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0036] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution. Unless otherwise specified, all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0037] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0038] Unless otherwise specified, the terms "include" and "comprising" used in this application are open-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0039] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0040] Solar cells include but are not limited to perovskite cells. Perovskite solar cells are solar cells that use perovskite materials as light-absorbing layers. They have the advantages of cost reduction and efficiency improvement, high weak light effect, and a wide range of application scenarios. They are an excellent choice for the new generation of mass-produced photovoltaic cells. Taking perovskite cells as an example, their hole transport layer materials are mainly organic materials, and organic materials are not dense enough. For example, when perovskite materials are formed on their surfaces, there is a problem of perovskite material decomposition, which leads to a decrease in the efficiency of perovskite cells. For another example, if a metal is used as a composite layer on the surface of the organic material hole transport layer to form a stacked cell, after a certain period of time, the metal can easily diffuse through the hole transport layer and contact the perovskite light-absorbing layer, thereby reducing the efficiency of the perovskite cell. In addition, the organic material hole transport layer itself has poor stability.

[0041] An embodiment of the present application provides a solar cell and a method for manufacturing the same. The solar cell will be described in detail below in conjunction with the method.

[0042] A solar cell according to one embodiment includes a first electrode layer, a first light absorbing layer, a first hole transport layer, and a second electrode layer that are stacked; a component of the first hole transport layer includes P-type doped SnO2.

[0043] Without wishing to be bound by any theory, the hole transport layer employed in this application comprises P-type doped SnO2. Since P-type doped SnO2 is entirely stable tetravalent tin, with no unstable monovalent or divalent tin, it exhibits superior stability compared to organic hole transport layers and SnOx (x < 2) hole transport layers. This significant advantage in stability allows the aforementioned solar cell to exhibit excellent photoelectric performance stability. The solar cell may comprise a metal composite layer, which also exhibits excellent stability.

[0044] It is worth noting that P-type doped SnO2 can be obtained by doping SnO2 with some doping elements. By adjusting the amount of doping elements, its band gap and energy band position can be adjusted, so that it can be well matched with the energy level of the perovskite light absorbing layer.

[0045] It can be understood that the above-mentioned solar cells can be stacked in sequence to form each layer through a process known in the art. For example, the remaining layers can be formed in sequence on the surface of the first electrode layer, and the remaining layers can also be formed in sequence on the surface of the second electrode layer, as long as the above-mentioned stacked structure is formed. The following is similar.

[0046] As an example, the P-type doped SnO2 includes SnO2 doped with at least one doping element selected from Ga, Sb, Mg, Al, and In. The doped SnO2 formed by these doping elements has good hole transport capability.

[0047] In some embodiments, the molar content of the doping element in the first hole transport layer is 2% to 30%. As an example, it can be 2%, 3%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 15%, 20%, 25%, or 30%. It can further be 5% to 30%, or 10% to 20%. Controlling the doping amount of the doping element within the above range is beneficial to improving the photoelectric performance stability of the solar cell. It can be understood that the molar content of the doping element refers to the percentage value of the amount of the doping element to the amount of tin dioxide.

[0048] In some embodiments, the thickness of the first hole transport layer is 10 nm to 50 nm. For example, the thickness may be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 40 nm, or 50 nm, and may further be 20 nm to 30 nm.

[0049] It is understood that the first hole transport layer can be used in a single-structure cell or a stacked cell, and can be used in solar cells including but not limited to perovskite cells. In other words, the solar cell can be a single-structure cell or a stacked cell, and can be, but not limited to, a perovskite cell.

[0050] The following uses a perovskite cell as an example, that is, the first light-absorbing layer is a perovskite light-absorbing layer.

[0051] It is understood that a first electron transport layer may be further provided between the first electrode layer and the first light absorbing layer.

[0052] In some embodiments, the solar cell is a tandem cell. Further, the tandem cell is a perovskite tandem cell, that is, the perovskite tandem cell includes not only a first light absorbing layer but also a second light absorbing layer, and at least one of the first light absorbing layer and the second light absorbing layer is a perovskite light absorbing layer.

[0053] Furthermore, the tandem cell is an all-perovskite tandem cell, i.e., both the first and second light-absorbing layers are perovskite light-absorbing layers. The band gap of one of the light-absorbing layers is larger than the band gap of the other light-absorbing layer. In other words, one of the first and second light-absorbing layers is a wide-bandgap perovskite light-absorbing layer, and the other is a narrow-bandgap perovskite light-absorbing layer.

[0054] It's understandable that the "wide bandgap" and "narrow bandgap" in the aforementioned perovskite light-absorbing layers are relative; that is, the bandgap of the second perovskite light-absorbing layer is larger than that of the first. Thus, when sunlight enters the wide-bandgap perovskite light-absorbing layer, the shorter wavelengths are first absorbed by the wide-bandgap perovskite light-absorbing layer, while the longer wavelengths are able to penetrate and be absorbed by the narrow-bandgap perovskite light-absorbing layer, maximizing the conversion of light energy into electrical energy.

[0055] It is understood that in the above solar cell, the wide-bandgap perovskite light-absorbing layer forms a wide-bandgap perovskite cell, and the narrow-bandgap perovskite light-absorbing layer forms a narrow-bandgap perovskite cell. It is understood that the above solar cell may include but is not limited to the above-mentioned two light-absorbing layers, that is, not limited to two perovskite cells, and may be provided with three or more cells as needed to form a stacked cell.

[0056] In some embodiments, the solar cell further comprises a composite layer and a second light-absorbing layer stacked sequentially between the first hole transport layer and the second electrode layer. This structure forms a stacked cell, with the composite layer serving as an interconnecting layer. In other words, the solar cell comprises a first electrode layer, a first light-absorbing layer, a first hole transport layer, a composite layer, a second light-absorbing layer, and a second electrode layer stacked sequentially. The solar cell can be formed by stacking the layers sequentially on the first electrode layer or on the second electrode layer, as long as the aforementioned stacked structure is achieved.

[0057] As a further example, if the first perovskite light absorption layer is a narrow-bandgap perovskite light absorption layer and the second perovskite light absorption layer is a wide-bandgap perovskite light absorption layer, then the second electrode layer is a transparent electrode (on the sunlight incident side). In other embodiments, the opposite arrangement is also possible. Furthermore, the perovskite material included in the first perovskite light absorption layer has a bandgap of 1.1 eV to 1.5 eV; further, the perovskite material included in the first perovskite light absorption layer has a bandgap of 1.6 eV to 2.3 eV.

[0058] Taking a narrow-bandgap perovskite light-absorbing layer as the first perovskite light-absorbing layer and a wide-bandgap perovskite light-absorbing layer as an example, the positive electrode in the wide-bandgap perovskite cell and the negative electrode in the narrow-bandgap perovskite cell serve as the external circuit connection electrodes of the solar cell; the negative electrode in the wide-bandgap perovskite cell and the positive electrode in the narrow-bandgap perovskite cell are connected via a recombination layer. Under illumination, holes in the wide-bandgap perovskite cell and electrons in the narrow-bandgap perovskite cell flow through the external circuit connection electrodes to the external circuit, thereby generating an external circuit current. Consequently, the electrons in the wide-bandgap perovskite cell and the holes in the narrow-bandgap perovskite cell recombine and annihilate in the recombination layer, thereby conducting the entire circuit and forming a closed-loop path.

[0059] Furthermore, the composite layer comprises at least one of a metal material and a transparent conductive oxide. Furthermore, the composite layer may be at least one of a metal layer and a transparent conductive oxide layer. Furthermore, the composite layer has a thickness of 0.5 nm to 3 nm, and as examples, may be 0.5 nm, 0.8 nm, 1 nm, 1.2 nm, 1.5 nm, 2 nm, or 3 nm, and further may be 0.8 nm to 1.2 nm. Furthermore, the metal layer includes, but is not limited to, a gold layer.

[0060] Furthermore, the components of the transparent conductive oxide layer include but are not limited to at least one of FTO (fluorine-doped tin oxide), ITO (indium tin oxide), AZO (aluminum-doped zinc oxide), BZO (boron-doped zinc oxide), IZO (indium zinc oxide) and ATO (antimony tin oxide).

[0061] Furthermore, the solar cell also includes a second electron transport layer provided between the composite layer and the second light absorbing layer, and the component of the second electron transport layer includes N-type SnO2. Since the second electron transport layer and the first hole transport layer close to the composite layer are all stable tetravalent tin, there is no unstable monovalent tin and divalent tin, which has good stability. It can be applied to solar cells such as those in which the composite layer is a metal layer to obtain good stability, and is suitable for both formal and trans structures. It is understandable that in addition to including N-type SnO2, the second electron transport layer may also include other electron transport materials; or it may only contain N-type SnO2 as an electron transport material, that is, an N-type SnO2 electron transport layer.

[0062] It is worth noting that N-type SnO2 includes but is not limited to at least one of undoped SnO2 and fluorine-doped SnO2. Furthermore, the fluorine doping molar content in the second electron transport layer is 2% to 30%, and as an example, can be 2%, 3%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 15%, 20%, 25%, 30%; further, it can be 5% to 30%, or 5% to 15%.

[0063] Furthermore, the thickness of the second electron transport layer is 10 nm to 50 nm. For example, it may be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 40 nm, or 50 nm, and may further be 20 nm to 30 nm.

[0064] In other embodiments of the stacked battery, the solar cell further includes a second electron transport layer and a second light absorbing layer stacked in sequence between the first hole transport layer and the second electrode layer, the second electron transport layer comprising N-type SnO2, and the second electron transport layer and the first hole transport layer are in contact with each other to form a tunnel junction. In other words, the solar cell includes a first electrode layer, a first light absorbing layer, a first hole transport layer, a second electron transport layer, a second light absorbing layer, and a second electrode layer stacked in sequence, the second electron transport layer is in contact with the first hole transport layer, and the second electron transport layer comprises N-type SnO2. The structure of the tunnel junction is adopted in this way, which shortens the conduction band and valence band spacing of the N-type SnO2 semiconductor and the P-type SnO2 semiconductor by high doping, thereby eliminating the need to insert a recombination layer as a defect energy level, and the carriers can still complete the transition by band-to-band tunneling and ultimately complete the recombination. In other words, the tunnel junction can replace the above-mentioned recombination layer and play the role of recombination and annihilation of holes and electrons, thereby making the entire circuit conductive and forming a closed-loop path. In addition, experiments have shown that solar cells made by replacing the above-mentioned composite layer with a tunnel junction have higher photoelectric conversion performance and higher photoelectric performance stability.

[0065] Furthermore, the thickness of the second electron transport layer forming the tunnel junction is 10 nm to 50 nm. As an example, it can be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 40 nm, 50 nm, and further can be 20 nm to 30 nm.

[0066] Furthermore, the thickness of the first hole transport layer forming the tunnel junction is 10 nm to 50 nm. As an example, it can be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 40 nm, 50 nm, and further can be 20 nm to 30 nm.

[0067] Regarding the tunnel junction formation process, since P-type doped SnO2, when used as a hole transport layer, can form the aforementioned tunnel junction when in contact with N-type SnO2, the contact between P-type doped SnO2 and N-type SnO2 is a homojunction contact. This makes it easier to adjust the energy band positions of the two homogeneous semiconductors to form a tunnel junction type. Carrier recombination is achieved through inter-band tunneling, thus replacing the use of a recombination layer. Therefore, the preparation of the second electron transport layer and the first hole transport layer that constitute the tunnel junction can be achieved by directly depositing the two SnO2s sequentially in the same equipment. In other words, the second electron transport layer and the first hole transport layer can be directly deposited sequentially in the same equipment through a vapor deposition process.

[0068] It should be further explained that, regardless of whether it is N-type SnO2 or P-type doped SnO2, the type of semiconductor SnO2 is controlled by the doping element and the doping amount, and the two SnO2 belong to the same material, and only because of the different doping types, they exhibit different conductivity types. Therefore, deposition processes such as ALD can be used to complete the preparation of both N-type SnO2 and P-type doped SnO2 in one process. For example, only SnO2 is made in the early stage, and when it reaches a certain thickness, the doping source is introduced to complete the deposition of P-type doped SnO2. Only one process is needed to complete the preparation of two materials. Or fluorine-doped SnO2 is prepared in the early stage, and the doping source is replaced later. In other words, N-type SnO2 and P-type doped SnO2 can be carried out in the same equipment, which greatly saves the process, so that the preparation of the electron transport layer and the hole transport layer can be completed in the same equipment.

[0069] It can be understood that, further, the preparation process of N-type SnO2 or P-type doped SnO2 can be a vapor deposition process such as PVD (physical vapor deposition), CVD (chemical vapor deposition), ALD (atomic deposition technology), etc., and ALD (atomic deposition technology) can be selected.

[0070] It is understood that each battery may be provided with at least one of an electron blocking layer and a hole blocking layer as required.

[0071] In some embodiments, the thickness of the first perovskite light absorbing layer and the second perovskite light absorbing layer is independently 200 nm to 1000 nm. For example, the thickness is 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, or 1000 nm; optionally, the thickness is 400 nm to 500 nm.

[0072] The perovskite light-absorbing layer can be prepared using methods commonly used in the art, including but not limited to sol-gel methods, coating, and multi-source co-evaporation. Coating methods include, but are not limited to, spin coating, slit coating, brush coating, wipe coating, doctor blade coating, screen coating, and spray coating. Furthermore, the perovskite light-absorbing layer is a three-dimensional perovskite thin film.

[0073] In some embodiments, the perovskite light-absorbing layer comprises a perovskite material. The general formula of the perovskite material is ABX3 or A2CDX6, where the A ion is a monovalent cation, the B ion is a divalent metal cation, the C ion is a monovalent metal cation, the D ion is a trivalent metal cation, and the X ion is a monovalent anion.

[0074] Optionally, the A ion includes at least one of an organic cation and a metal cation. More preferably, the organic cation includes at least one of an organic amine ion, a formamidinium group (FA), and an imidazole group; More preferably, the metal cation includes Li+ 、Na + , K + , Rb + and Cs + Further, the organic amine ion includes at least one of methylamino (MA), ethylamino, propylamino, butylamino, pentylamino and hexylamino.

[0075] Optionally, the B ions include Pb 2+ 、Sn 2+ 、Be 2+ Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ 、Zn 2+ 、Ge 2+ 、Fe 2+ 、Co 2+ 、Cu 2+ and Ni 2+ More preferably, the B ions include Pb 2+ and Sn 2+ One or both of .

[0076] Optionally, the C ions include Cs + 、Ag + , K + and Ru + At least one of .

[0077] Optionally, the D ions include Bi 3+ 、Ni 3+ 、Fe 3+ and Cu 3+ At least one of;

[0078] Optionally, the X ions include F - 、Cl - Br - and I - At least one of; Optionally, the X ions include Cl - Br - and I - At least one of .

[0079] It is understood that the perovskite material in the above-mentioned perovskite light absorbing layer can be selected from at least one of CsFAPbX3, CsMAPbX3, CsFAMAPbX3, CsPbX3, MAPbX3, FAPbX3, CsFAPbSnX3, CsMAPbSnX3, CsFAMAPbSnX3, CsPbSnX3, MAPbSnX3, and FAPbSnX3. Further, as an example, the perovskite material in the above-mentioned perovskite light absorbing layer can be selected from at least one of CsFAPbI3, CsPbI3, and FAPbI3.

[0080] As an example, the general formula of perovskite materials is as follows: Cs a FA b MA c Pb d Sn e I f Br g , among them, a=0~0.05, b=0.8~0.95, c=0~0.1, d=0.5~1, e=0~0.5, f=2.0~3, g=0~1, a+b+c=1, d+e=1, f+g=3.

[0081] Understandably, in order to enable light to be effectively transmitted to the perovskite light-absorbing layer, at least one of the first electrode layer and the second electrode layer in the above-mentioned battery is set as a transparent electrode, and the other is a counter electrode layer.

[0082] It can be understood that solar cells include a regular structure and a trans structure in terms of structure.

[0083] The transparent electrode can be a transparent conductive metal oxide electrode. Examples of transparent electrode materials include transparent conductive glass such as FTO (fluorine-doped tin oxide), ITO (indium tin oxide), AZO (aluminum-doped zinc oxide), BZO (boron-doped zinc oxide), and IZO (indium zinc oxide). It is understood that in addition to glass as a substrate, transparent electrodes can also utilize transparent flexible substrates. Specifically, the transparent flexible substrate can be made of an organic polymer material, which can be a mixture of one or more of the following materials in varying proportions: polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), and polydimethylsiloxane (PDMS).

[0084] The material of the counter electrode layer includes, but is not limited to, an organic material, an inorganic material, or a conductive material obtained by mixing organic and inorganic materials in different proportions.

[0085] Furthermore, the counter electrode layer is a metal electrode. Metallic conductive materials for the counter electrode layer include, but are not limited to, gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), bismuth (Bi), platinum (Pt), magnesium (Mg), or mixtures thereof. In some embodiments, the counter electrode layer may also be a transparent electrode.

[0086] For laminated structures containing composite layers, see, as an example, Figure 1 , shows a solar cell 1 according to an embodiment, including a stacked first electrode layer 11, a first electron transport layer 12, a first perovskite light absorption layer 13, a first hole transport layer 14, a recombination layer 15, a second electron transport layer 16, a second perovskite light absorption layer 17, a second hole transport layer 18, and a second electrode layer 19. The material or component of the first hole transport layer 14 includes the aforementioned P-type doped SnO2, and the material or component of the second electron transport layer 16 includes the aforementioned N-type SnO2.

[0087] Furthermore, the first electrode layer 11 is a counter electrode layer, the second electrode layer 19 is a transparent electrode, and the band gap of the first perovskite light-absorbing layer 13 is smaller than the band gap of the second perovskite light-absorbing layer 17. The above-described method for preparing the solar cell 1 can be performed by sequentially forming each layer on the second electrode layer 19. In this case, a trans structure including a composite layer is obtained.

[0088] For another example, the first electrode layer 11 is a transparent electrode, the second electrode layer 19 is a counter electrode, and the band gap of the first perovskite light absorbing layer 13 is greater than the band gap of the second perovskite light absorbing layer 17. The above-described solar cell 1 can be prepared by sequentially forming each layer on the first electrode layer 11. This results in a positive structure containing a composite layer.

[0089] For example, see the stacked structure using tunnel junctions instead of composite layers. Figure 2 , shows a solar cell 1 according to an embodiment, comprising a stacked first electrode layer 11, a first electron transport layer 12, a first perovskite light absorption layer 13, a first hole transport layer 14, a second electron transport layer 16, a second perovskite light absorption layer 17, a second hole transport layer 18, and a second electrode layer 19. The first hole transport layer 14 and the second electron transport layer 16 are in direct contact with each other to form a tunneling junction. The material of the first hole transport layer 14 includes the aforementioned P-type doped SnO2, and the material of the second electron transport layer 16 includes the aforementioned N-type SnO2.

[0090] The formal and trans structures of the stacked structure using a tunnel junction are similar to the formal and trans structures of the stacked structure of the composite layer, and are not described in detail here.

[0091] Furthermore, in the above solar cell, for example, in a trans-type structure, another electron transport layer, such as a fullerene C60 layer, is provided between the second perovskite light absorbing layer 17 and the second electron transport layer 16. The fullerene C60 layer provided on the second perovskite light absorbing layer 17 can protect the underlying perovskite material and inhibit its high-temperature decomposition during the deposition process of the second electron transport layer 16, such as N-type SnO2.

[0092] Furthermore, in the inverse structure battery, the first electrode layer 11 includes a tin dioxide layer and a silver layer sequentially stacked on the first electron transport layer 12. Furthermore, the first electron transport layer 12 is a fullerene C60 layer.

[0093] In some examples, a method for preparing a perovskite light-absorbing layer includes the following steps: mixing a material containing A (such as AX), BX2 (or CX, DX3) with a solvent to prepare a perovskite precursor solution; then coating the perovskite precursor solution on a corresponding substrate, and annealing to obtain a perovskite light-absorbing layer.

[0094] The above-mentioned first electrode layer, hole transport layer, electron transport layer and second electrode layer can be prepared by the preparation methods commonly used in the art, including but not limited to solution method and solid deposition method. The solution method includes any one of spin coating, spray coating, blade coating and slit coating, and the solid deposition method includes any one of vacuum evaporation, sputtering deposition, plasma deposition and ion deposition.

[0095] Furthermore, as an example, the material of the above-mentioned second hole transport layer 18 includes but is not limited to at least one of the following materials and their derivatives: poly [bis (4-phenyl) (2,4,6-trimethylphenyl) amine] (PTAA), NiOx (nickel oxide), 2,2',7,7'-tetrakis [N, N-di (4-methoxyphenyl) amino] -9,9'-spirobifluorene (Spiro-OMeTAD), WO3, poly 3,4-ethylenedioxythiophene: polystyrene sulfonate (PEDOT:PSS), poly-3 hexylthiophene (P3HT), triphenylamine compounds and carbazole compounds, etc., which can transport holes and block electrons. One or more materials.

[0096] Triphenylamine compounds include, but are not limited to, triphenylamine (H101) with a triptycene core and 3,4-ethylenedioxythiophene-methoxytriphenylamine (EDOT-OMeTPA). Carbazole compounds include, but are not limited to, N-(4-phenylamino)carbazole-spirobifluorene (CzPAF-SBF) and phosphate carbazole compounds. Furthermore, the second hole transport layer comprises at least one of PTAA and a nickel oxide (NiOx) compound.

[0097] Further, as an example, the material of the first electron transport layer 12 can be, but is not limited to, at least one of the following materials and their derivatives: imide compounds, quinone compounds, fullerene C60 and its derivatives, methoxytriphenylamine-fluoroformamidine (OMeTPA-FA), [6,6]-phenyl C61 butyric acid methyl ester (PCBM), [6,6]-phenyl C71 Methyl butyrate (PC71BM), calcium titanate (CaTiO3), lithium fluoride (LiF), calcium fluoride (CaF2), poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid (PEDOT:PSS), poly(3-hexylthiophene) (P3HT), triphenylamine with triptycene as the core (H101), 3,4-ethylenedioxythiophene-methoxytriphenylamine (EDOT-OMeTPA), N-(4-phenylamino)carbazole-spirobifluorene (CzPAF-SBF), polythiophene, metal oxide, silicon oxide (SiO2), strontium titanate (SrTiO3), cuprous thiocyanate (CuSCN). Furthermore, the metal element in the metal oxide is selected from one of Mg, Ni, Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, and Cr.

[0098] One embodiment of the present application further provides a photovoltaic module, which includes the above-mentioned solar cell.

[0099] The solar cell has high light conversion efficiency and good stability, and can improve the efficiency of photovoltaic modules.

[0100] The photovoltaic module includes one or more of the aforementioned solar cells, which can be selected based on the specific application scenario. Furthermore, the photovoltaic module includes multiple solar cells, which are connected in series or parallel to form a cell. Furthermore, the photovoltaic module may also include a tandem cell, which includes one or more of the aforementioned solar cells. Tandem cells include, but are not limited to, crystalline silicon / perovskite tandem cells, all-perovskite tandem cells, and copper indium gallium selenide and other thin-film / perovskite tandem cells.

[0101] In some embodiments, the photovoltaic module further includes a photovoltaic glass layer, a bonding layer, and a back sheet.

[0102] Adhesive layers are provided on both surfaces of the cell, a back plate is provided on the surface of one of the adhesive layers away from the cell, and a photovoltaic glass layer is provided on the surface of the other adhesive layer away from the cell.

[0103] The photovoltaic glass layer and back panel are used to protect the solar cells, and have the functions of sealing, insulation and waterproofing; the bonding layer plays the role of bonding the photovoltaic glass layer and the battery cell, and bonding the back panel and the battery cell.

[0104] Optionally, the photovoltaic glass layer is made of tempered glass, the back panel is made of TPT (polyvinyl fluoride) or TPE (thermoplastic elastomer), and the adhesive layer is made of EVA (polyethylene-polyvinyl acetate copolymer).

[0105] Furthermore, the photovoltaic module further includes a junction box and an outer frame.

[0106] The junction box is used to protect the power generation system of the entire photovoltaic module. It is equivalent to a current transfer station. When a battery cell short-circuits, the junction box will automatically disconnect the short-circuited battery string.

[0107] The outer frame can support and protect the entire photovoltaic module. The frame can be made of aluminum alloy, which has excellent strength and corrosion resistance.

[0108] Furthermore, silicone is used to bond and seal the connection between the frame and other parts of the photovoltaic module. Photovoltaic modules can convert solar energy into electrical energy, which can be stored in batteries or used to drive loads.

[0109] In some embodiments, the photovoltaic component is a solar panel.

[0110] One embodiment of the present application further provides a photovoltaic system, comprising the above-mentioned photovoltaic module.

[0111] The photovoltaic system utilizes the photovoltaic effect of the solar cells in the above photovoltaic modules to directly convert solar radiation energy into electrical energy with high efficiency; further, the above photovoltaic system is a photovoltaic power generation system.

[0112] Photovoltaic modules are the core part of photovoltaic power generation systems. The above photovoltaic system includes one or more photovoltaic modules, which can be selected according to the specific application scenario; further, when the above photovoltaic system includes multiple photovoltaic modules, the multiple photovoltaic modules form a photovoltaic array.

[0113] The above photovoltaic system can be an independent photovoltaic power generation system or a grid-connected photovoltaic power generation system.

[0114] An independent photovoltaic power generation system consists of a photovoltaic array, a battery bank, a charge controller, a power electronic converter (inverter), and a load. Its operating principle is that solar radiation energy is first converted into electrical energy by the photovoltaic array, which is then converted by the power electronic converter to power the load. Meanwhile, excess electrical energy is stored as chemical energy in an energy storage device after passing through the charge controller. In periods of insufficient sunlight, the energy stored in the battery is converted to 220V, 50Hz AC power after being boosted by the power electronic inverter, filtering, and power frequency transformer to supply the AC load.

[0115] A grid-connected photovoltaic power generation system consists of a photovoltaic array, a high-frequency DC / DC boost circuit, a power electronic converter (inverter), and system monitoring. Its operating principle is that solar radiation energy is converted by the photovoltaic array, then converted to high-voltage DC through high-frequency DC conversion. This is then inverted by a power electronic inverter and output to the grid a sinusoidal AC current with a frequency consistent with the grid voltage.

[0116] The above two photovoltaic power generation systems have their own characteristics and can be selected according to specific application scenarios.

[0117] One embodiment of the present application provides an electrical device, comprising at least one of the aforementioned solar cell and the aforementioned photovoltaic module.

[0118] In some embodiments, the solar cell or photovoltaic module can be used as a power source for an electrical device or as an energy storage unit for an electrical device.

[0119] Furthermore, the above-mentioned electrical devices may include mobile devices, such as mobile phones, laptop computers, etc., electric vehicles, electric trains, ships and satellites, but are not limited thereto.

[0120] Figure 3 The power consumption device 2 is used as an example. The power consumption device 2 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.

[0121] One embodiment of the present application provides a power generation device, comprising at least one of the above-mentioned solar cell and the above-mentioned photovoltaic module.

[0122] In order to make the technical problems, technical solutions and beneficial effects solved by this application clearer, the application will be further described in detail below with reference to the embodiments and drawings. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its applications. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0123] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. All reagents or instruments used without specifying the manufacturer are commercially available conventional products.

[0124] 1. Device Preparation

[0125] Example 1

[0126] The specific preparation process of the stacked battery is as follows:

[0127] 1) Transparent electrode layer: The material of the transparent electrode layer is indium tin oxide (ITO). The transparent electrode layer is provided on a glass substrate to form an ITO transparent conductive glass. The ITO transparent conductive glass is cleaned in sequence with acetone, alcohol, and deionized water, and dried for later use.

[0128] 2) Hole Transport Layer: [4-(3,6-Dimethoxy-9H-carbazol-9-yl)butyl]phosphoric acid (MeO-4PACz) was added to an ethanol solvent and stirred. The ethanol solution of MeO-4PACz was spin-coated onto the transparent electrode layer (spin coating speed of 4000 rpm for 30 seconds). The layer was then transferred to a hot plate and annealed at 100°C for 10 minutes to form a 1.5 nm thick hole transport layer.

[0129] 3) Perovskite light-absorbing layer:

[0130] 3 mg of FAI, 59 mg of FABr, 46 mg of CsI, 25 mg of CsBr, 428 mg of PbI2, and 209 mg of PbBr2 were added to 1 mL of a mixed solvent of DMF and DMSO (DMF and DMSO volume ratio is 3:1), stirred at 600 rpm on a magnetic stirrer for 8 h, and filtered to prepare a perovskite precursor solution;

[0131] 100 μL of the above perovskite precursor solution was spin-coated onto the above hole transport layer (first at a spin-coating speed of 2000 rpm and an acceleration of 200 rpm / s for 10 s, then at a spin-coating speed of 4000 rpm and an acceleration of 1000 rpm / s for 25 s), and then 200 μL of chlorobenzene was added dropwise to the spin-coated perovskite precursor solution, followed by spin-coating the above perovskite precursor solution (spin-coating speed of 4000 rpm, spin-coating time of 15 s), and then transferred to a hot stage for annealing at 100°C for 15 min to form a perovskite light-absorbing layer with a thickness of 500 nm.

[0132] 4) Electron transport layer: A 20 nm thick SnO2 layer was deposited on the perovskite light absorbing layer using atomic layer deposition (ALD) with a Sn source (TDMASn, tetrakis(dimethylamino)tin(IV)) and an O source (H2O) to form an electron transport layer.

[0133] 5) Composite layer: Use evaporation equipment to evaporate 1nm thick Au on SnO2 as a composite layer.

[0134] 6) Hole Transport Layer: Using an atomic layer deposition system, a 25nm thick layer of p-type doped SnO2 (Ga-doped SnO2) was deposited on Au using a Ga source (TMG, trimethylgallium), an O source (H2O), and a Sn source (TDMASn). The Ga doping level in the Ga-doped SnO2 was controlled by adjusting the ratio of the Ga, O, and Sn sources.

[0135] 7) Perovskite light-absorbing layer: 2 mg of CH(NH2)2I, 85 mg of CH3NH2I, 4 mg of PbI2, 335 mg of SnI2, and 0.5 mg of MeO-4PACz were added to 1 mL of a mixed solvent of DMF and DMSO (DMF and DMSO, volume ratio: 3:1), stirred at 600 rpm on a magnetic stirrer for 2 h, and filtered to prepare a perovskite precursor solution; 100 μL of the above perovskite precursor solution was spin-coated onto the hole transport layer prepared in 6) above, specifically, first at a spin-coating speed of 1000 rpm and an acceleration of 200 rpm / s for 10 s, and then at a spin-coating speed of 3000 and an acceleration of 1000 rpm / s for 20 s. Then, 350 μL of ethyl acetate was added to the spin-coated perovskite precursor solution, and then the above perovskite precursor solution was spin-coated again (spin coating speed was 4000 rpm, spin coating time was 20 s), and then transferred to a hot stage and annealed at 100 ° C for 10 minutes to form a perovskite light-absorbing layer with a thickness of 1 μm.

[0136] 8) Electron transport layer: A 10 nm thick layer of bathocuproin (BCP) is evaporated on the perovskite light absorbing layer to form an electron transport layer.

[0137] 9) Counter electrode layer: A layer of metal copper (Cu) with a thickness of 100 nm was evaporated on the electron transport layer obtained in 8) above to form a counter electrode layer, thereby preparing a stacked solar cell device.

[0138] Example 2

[0139] The method is basically the same as Example 1, except that the content of Ga doped in the preparation of the hole transport layer in step 6) is different (see Table 1), which is specifically achieved by controlling the content ratio of the Ga source, the O source and the Sn source.

[0140] Example 3

[0141] The method is basically the same as Example 1, except that the content of Ga doped in the preparation of the hole transport layer in step 6) is different (see Table 1), which is specifically achieved by controlling the content ratio of the Ga source, the O source and the Sn source.

[0142] Example 4

[0143] The method is basically the same as Example 1, except that a different doping source is used in step 6) to prepare the hole transport layer, specifically Sb. The specific steps are as follows:

[0144] Atomic layer deposition equipment was used to deposit P-type doped SnO2 (Sb-doped SnO2) with the same thickness on Au.

[0145] Example 5

[0146] The process is basically the same as Example 1, except that a different doping source is used in step 6) to prepare the hole transport layer, specifically Mg. The specific steps are as follows:

[0147] Atomic layer deposition equipment was used to deposit P-type doped SnO2 (Mg-doped SnO2) with the same thickness on Au.

[0148] Example 6

[0149] The method is essentially the same as Example 1, except that steps 4) to 6) are omitted. Specifically, in Example 2, a tunnel junction is used instead of steps 4) to 6), the composite layer is omitted, and the electron transport layer and the hole transport layer are directly formed in the ALD device on the perovskite light absorption layer obtained in step 3). The specific preparation steps are as follows:

[0150] Using an atomic layer deposition (ALD) device, only Sn and O sources were introduced initially to deposit SnO2 to a thickness of 25nm. After 200 cycles, Ga source was introduced. Thereafter, the three sources (Ga, O, and Sn) were alternately cycled for 200 cycles to form Ga-doped SnO2 with the same thickness, completing the tunnel junction fabrication.

[0151] Example 7

[0152] The method is basically the same as Example 6, except that the content of Ga doped in the preparation of the hole transport layer in step 6) is different (see Table 1), which is achieved by controlling the content ratio of the three sources (Ga source, O source and Sn source).

[0153] Example 8

[0154] The method is basically the same as Example 6, except that the content of Ga doped in the preparation of the hole transport layer in step 6) is different (see Table 1), which is achieved by controlling the content ratio of the three sources (Ga source, O source and Sn source).

[0155] Example 9

[0156] The method is basically the same as Example 6, except that a different doping source is used in step 6) to prepare the hole transport layer, specifically Al. The specific steps are as follows:

[0157] Atomic layer deposition equipment was used to deposit P-type doped SnO2 (Al-doped SnO2) with the same thickness on Au.

[0158] Example 10

[0159] The method is basically the same as Example 1, except that a different doping source is used in step 6) to prepare the hole transport layer, specifically In doping. The specific steps are as follows:

[0160] Atomic layer deposition equipment was used to deposit P-type doped SnO2 (In-doped SnO2) of the same thickness on Au.

[0161] Comparative Example 1

[0162] The process is basically the same as Example 1, except that the hole transport layer in step 6) is made of an organic material. The specific steps are as follows:

[0163] A 2 mg / mL PTAA organic hole transport layer was spin-coated on Au at a rate of 5000 rpm / s, and then annealed on a hot plate at 100° C. for 10 minutes to obtain a hole transport layer with a thickness of approximately 20 nm.

[0164] Comparative Example 2

[0165] The method is basically the same as Example 1, except that in step 6), the hole transport layer is tin monoxide with a constant thickness, which is obtained by controlling the content ratio of the tin source and the oxygen source.

[0166] 2. Performance Testing

[0167] 1. Detect the doping amount in the hole transport layer obtained in step 6).

[0168] The specific steps are as follows: disassemble the perovskite solar cell, peel off the perovskite solar cell layer by layer, and obtain 7) the upper perovskite layer of the perovskite light absorbing layer and 6) the obtained hole transport layer sample. Use an organic solvent to dissolve the sample to remove the perovskite material. Since tin dioxide is not dissolved by organic solvents and is retained, the collected tin dioxide sample is used to test and analyze the element type and content using XPS.

[0169] 2. Photovoltaic conversion efficiency of perovskite solar cells

[0170] Under standard simulated sunlight (AM 1.5G, 100 mW / cm 2 ) irradiation, the battery performance is tested using Keithley2400SMU to obtain the IV curve. According to the IV curve and the data fed back by the test equipment, the short-circuit current Jsc (unit: mA / cm 2), open-circuit voltage Voc (V), maximum optical output current Jmpp (mA), and maximum optical output voltage Vmpp (V). The cell's fill factor (FF) (in %) is calculated using the formula FF = Jsc × Voc / (Jmpp × Vmpp). The cell's photoelectric conversion efficiency (PCE) (in %) is calculated using the formula PCE = Jsc × Voc × FF / Pin (in %). Pin represents the incident light input power (in mW).

[0171] According to the above process, four solar cells obtained in each of the above embodiments and comparative examples were tested respectively, and the obtained results were averaged. The specific results are shown in Table 1.

[0172] 3. Stability test

[0173] The perovskite solar cell was placed at 65°C and 100 mW / cm 2 The photoelectric conversion efficiency of the sample was continuously irradiated with a light source of 100 nm and the change of the photoelectric conversion efficiency with aging time was tracked. The time required for the photoelectric conversion efficiency to decay to 80% of the initial efficiency was recorded as T. 80 The size of this parameter indicates the stability of the perovskite solar cell. The data in Table 2 are rounded to integer multiples of 10.

[0174] The perovskite solar cells obtained in the above embodiment and comparative example were tested according to the above process. The specific values ​​are shown in Table 2.

[0175] Some parameters of various embodiments and comparative examples are shown in Table 1. 6) The doping amount in the hole transport layer refers to the molar content of the doping element.

[0176] Table 1

[0177]

[0178] The performance results of each embodiment and comparative example are shown in Table 2.

[0179] Table 2

[0180]

[0181] From the above table, we can see that the T 80It is shorter, indicating that its photoelectric stability is poor. Among them, Comparative Example 1 uses the organic material PTAA as the hole transport layer. Due to its own poor stability and the problem of instability of the perovskite light absorption layer, its photoelectric stability is reduced. Comparative Example 2 uses tin monoxide as the hole transport layer. As the use time increases, its photoelectric stability decreases. It may be that tin monoxide is gradually oxidized during use and partially converted into tin dioxide. Undoped tin dioxide is an electron transport material and its hole transport performance is poor. Each embodiment sets P-type doped SnO2 as the hole transport layer, and its photoelectric performance stability is significantly improved.

[0182] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A solar cell, characterized in that: It comprises a first electrode layer, a first light absorption layer, a first hole transport layer and a second electrode layer which are stacked; the component of the first hole transport layer comprises P-type doped SnO2.

2. The solar cell according to claim 1, wherein The P-type doped SnO2 includes SnO2 doped with at least one doping element selected from Ga, Sb, Mg, Al and In.

3. The solar cell according to any one of claims 1 to 2, characterized in that: The molar content of the doping element in the first hole transport layer is 2% to 30%.

4. The solar cell according to any one of claims 1 to 3, characterized in that The thickness of the first hole transport layer is 10 nm to 50 nm.

5. The solar cell according to any one of claims 1 to 4, characterized in that The solar cell further includes a composite layer and a second light absorption layer stacked in sequence between the first hole transport layer and the second electrode layer.

6. The solar cell according to claim 5, characterized in that The components of the composite layer include at least one of a metal material and a transparent conductive oxide.

7. The solar cell according to any one of claims 5 to 6, characterized in that: The thickness of the composite layer is 0.5 nm to 3 nm.

8. The solar cell according to any one of claims 5 to 7, characterized in that: The solar cell further includes a second electron transport layer disposed between the composite layer and the second light absorbing layer, wherein the second electron transport layer includes N-type SnO2.

9. The solar cell according to any one of claims 1 to 4, characterized in that: The solar cell further includes a second electron transport layer and a second light absorption layer sequentially stacked between the first hole transport layer and the second electrode layer, the second electron transport layer is in contact with the first hole transport layer, and a component of the second electron transport layer includes N-type SnO2.

10. The solar cell according to any one of claims 8 to 9, characterized in that: The N-type SnO 2 includes at least one of undoped SnO 2 and fluorine-doped SnO 2 .

11. The solar cell according to any one of claims 8 to 10, characterized in that: The thickness of the second electron transport layer is 10 nm to 50 nm.

12. The solar cell according to any one of claims 5 to 11, characterized in that The first light absorbing layer and the second light absorbing layer are each independently a perovskite light absorbing layer.

13. The solar cell according to any one of claims 5 to 12, characterized in that: The first light absorbing layer is a narrow-bandgap perovskite light absorbing layer, the second light absorbing layer is a wide-bandgap perovskite light absorbing layer, and the second electrode layer is a transparent electrode.

14. A method for preparing a solar cell according to any one of claims 1 to 13, characterized in that: The steps include: The first electrode layer, the first light absorbing layer, the first hole transport layer and the second electrode layer are stacked and formed.

15. The method for preparing a solar cell according to claim 14, wherein: The preparation method comprises the following steps: The first electrode layer, the first light absorbing layer, the first hole transport layer, the composite layer, the second light absorbing layer and the second electrode layer are stacked and formed.

16. The method for preparing a solar cell according to claim 14, wherein: The preparation method comprises the following steps: The first electrode layer, the first light absorbing layer, the first hole transport layer, the second electron transport layer, the second light absorbing layer and the second electrode layer are stacked, the second electron transport layer is in contact with the first hole transport layer, and the component of the second electron transport layer includes N-type SnO2.

17. A photovoltaic module, characterized in that: The solar cell according to any one of claims 1 to 13 is included.

18. A photovoltaic system, characterized in that: Comprising the photovoltaic module according to claim 17.

19. An electrical device, characterized in that: The method comprises at least one selected from the group consisting of the solar cell according to any one of claims 1 to 13 and the photovoltaic module according to claim 17.

20. A power generation device, characterized in that: The method comprises at least one selected from the group consisting of the solar cell according to any one of claims 1 to 13 and the photovoltaic module according to claim 17.

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