Trans-perovskite solar cell, preparation method thereof and photovoltaic module

Abstract

The invention provides a trans-perovskite solar cell, a preparation method thereof and a photovoltaic module. The trans-perovskite solar cell sequentially comprises a substrate, a hole transport layer, a perovskite absorption layer, an electron transport layer, a transition layer and a metal electrode from bottom to top, the electron transport layer comprises a tin oxide layer, and the general chemical formula of the transition layer is MxSn (1-x) Oy, where 0 lt; x is smaller than or equal to 0.1, y is larger than or equal to 1 and smaller than 2, and M is a metal ion with the ion radius smaller than 120 pm. By introducing the transition layer, ohmic contact which is tighter, better in conductivity and low in resistance value can be established between the tin oxide layer and the metal electrode, the work function of the surface of the device is improved, an energy band is bent downwards, and the Schottky barrier is reduced, so that the electron transmission efficiency and the overall performance of the device are remarkably improved; meanwhile, it is ensured that no extra preparation complexity or cost is introduced, and more remarkable economic benefits can be obtained in large-scale practical application.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, specifically relating to an inverted perovskite solar cell, its preparation method, and a photovoltaic module. Background Technology

[0002] With the increasing demand for clean energy, perovskite solar cells have attracted much attention as a high-efficiency energy conversion technology. Tin oxide is widely used in the electron transport layer of the cell, playing a crucial conductive role. However, several challenges currently hinder further improvements in the overall performance of perovskite solar cells.

[0003] In current inverted perovskite solar cells, the contact between the tin oxide layer and the metal electrode has always been a key factor limiting device performance. Traditional structures often have a large Schottky barrier between these two materials, leading to a decrease in electron transport efficiency and thus affecting the overall performance of the solar cell. This poor electron transport efficiency is particularly pronounced under high temperatures or long-term use, limiting the device's performance.

[0004] Current research attempts to improve the contact between tin oxide layers and metal electrodes through stacking methods, but these methods often involve complex process steps, increasing fabrication costs and making them difficult to implement in large-scale production. Furthermore, these traditional methods can result in excessively thick transition layers, which in turn affects the light absorption and photoelectric conversion efficiency of the device.

[0005] Therefore, how to effectively improve the ohmic contact between the tin oxide layer and the metal electrode, reduce the Schottky barrier, and thus improve the device performance of electron transport efficiency without introducing additional fabrication costs is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an inverted perovskite solar cell, its fabrication method, and a photovoltaic module. This invention introduces a chemical formula of M... x Sn 1-x O y The transition layer can establish a tighter, more conductive, and lower-resistance ohmic contact between the tin oxide layer and the metal electrode, and improve the work function of its surface. The energy band bends downward and the Schottky barrier is reduced, thus significantly improving the electron transport efficiency and overall performance of the device, while ensuring that no additional fabrication complexity and cost are introduced, which can achieve more significant economic benefits in large-scale practical applications.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a reverse perovskite solar cell, which sequentially includes a substrate, a hole transport layer, a perovskite absorption layer, an electron transport layer, a transition layer, and a metal electrode from bottom to top.

[0009] The electron transport layer includes a tin oxide layer, and the chemical general formula of the transition layer is M x Sn 1-x O y , where 0 < x ≤ 0.1, 1 ≤ y < 2, and M is a metal ion with an ionic radius less than 120 pm.

[0010] It should be noted that tin oxide is an N-type semiconductor, and the work function of the thin film is greater than 3.4 eV and less than 3.66 eV, while the work function of a metal electrode such as a silver electrode is 4.26 eV. Therefore, when tin oxide contacts with metallic silver, a potential difference will form on the surface of the material, and electrons flow from the tin oxide semiconductor to the metal. When it is stable, the Fermi level of the system reaches the same level, and a positive space charge region forms on the surface of the tin oxide semiconductor. The direction of the electric field is: from the semiconductor to the metal, and the energy band bends upward. In this way, it will block the flow of electrons from the tin oxide semiconductor to the silver metal, forming a blocking layer. Electrons must cross the potential barrier at the interface, which is also called the Schottky barrier.

[0011] Therefore, the present invention introduces a transition layer with the chemical general formula of M x Sn 1-x O0] y to establish a closer, better conductive and low-resistance ohmic contact between the tin oxide layer and the metal electrode, and improve its surface work function, the energy band bends downward, reducing the Schottky barrier. Therefore, the electron transport efficiency and overall performance of the device are significantly improved, while ensuring that no additional preparation complexity and cost are introduced, and more significant economic benefits can be achieved in large-scale practical applications.

[0012] In the present invention, 0 < x ≤ 0.1, for example, it can be 0.02, 0.04, 0.05, 0.07 or 0.1, etc., and 1 ≤ y < 2, for example, it can be 1, 1.2, 1.4, 1.6 or 1.8, etc.

[0013] In the present invention, due to the existence of interstitial defects in the tin oxide thin film, the M element with an ionic radius less than 120 pm can reduce the structural defects in the thin film to improve the electrical properties of the thin film. By reasonably regulating the ratio of x and y, the conductivity and work function of the transition layer can be effectively balanced.

[0014] As a preferred technical solution of the present invention, the thickness of the transition layer is 2 - 4 nm, for example, it can be 2 nm, 2.5 nm, 3 nm, 3.5 nm or 4 nm, etc.

[0015] In this invention, the transition layer, acting as a tunneling junction, needs to be sufficiently thin while simultaneously covering the surface of the tin oxide layer to form an ohmic contact between the tin oxide layer and the metal electrode. Therefore, the thickness of the transition layer is limited to 2-4 nm. If the transition layer is too thin, it may not be able to completely cover the surface of the tin oxide layer. If the transition layer is too thick, electrons will be unable to penetrate the tunneling junction.

[0016] Preferably, the thickness of the tin oxide layer is greater than the thickness of the transition layer.

[0017] Preferably, the thickness ratio of the tin oxide layer, the transition layer, and the metal electrode is (15-25):(2-4):(80-120), wherein the tin oxide layer is selected from the range of "15-25", which can be, for example, 15, 17, 20, 22, or 25, etc.; the transition layer is selected from the range of "2-4", which can be 2, 2.5, 3, 3.5, or 4, etc.; and the metal electrode is selected from the range of "80-120", which can be, for example, 80, 90, 100, 110, or 120, etc.

[0018] In this invention, if the thickness ratio of the tin oxide layer to the transition layer is too small, electrons may not be able to penetrate the tunnel junction. If the thickness ratio of the tin oxide layer to the transition layer is too large, the surface of the tin oxide layer may not be completely covered.

[0019] In a preferred embodiment of the present invention, M comprises Mg ions.

[0020] Preferably, the metal electrode includes any one of a silver electrode, a copper electrode, or a gold electrode.

[0021] As a preferred technical solution of the present invention, the light transmittance of the transition layer is ≥85%, for example, it can be 85%, 90%, 95% or 99%, etc.

[0022] The light absorption rate of the transition layer is ≤2%, for example, it can be 2%, 1.5%, 1% or 0.5%, etc.

[0023] As a preferred embodiment of the present invention, the hole transport layer comprises a nickel oxide layer and / or a self-assembled molecular layer.

[0024] Preferably, the self-assembled molecular layer comprises any one or a combination of at least two of the following: Meo-2PACz ([2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphate), Meo-4PACz ([4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid), 2PACz (2-[(2-chlorophenyl)(phenyl)amino]ethyl benzoate), 4PACz ((4-(9H-carbazole-9-yl)butyl)phosphonic acid), or 4PADCB ((4-(7H-dibenzo[c,g]carbazole-7-yl)butyl)phosphonic acid).

[0025] Preferably, the thickness of the hole transport layer is 5-25 nm, for example, it can be 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, etc.

[0026] Preferably, the thickness of the perovskite absorption layer is 400-600 nm, for example, it can be 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, etc.

[0027] Preferably, the chemical general formula of the perovskite absorption layer is ABX3, where A is any one or a combination of at least two of formamidinium ions, methylammonium ions or cesium ions, B is lead ions and / or tin ions, and X is any one or a combination of at least two of chloride ions, bromide ions or iodide ions.

[0028] Preferably, the electron transport layer further includes a C 60 layer, and the C 60 layer and the tin oxide layer are sequentially stacked along the direction away from the substrate.

[0029] It should be noted that the type of the substrate in the present invention is not limited. Exemplarily, for example, it can be ITO (indium tin oxide) glass or FTO (fluorine-doped tin oxide) glass, etc.

[0030] In a second aspect, the present invention provides a method for preparing a tandem perovskite solar cell as described in the first aspect, and the preparation method includes the following steps:

[0031] Deposit a hole transport layer, a perovskite absorption layer, an electron transport layer, a transition layer and a metal electrode on the substrate in sequence.

[0032] As a preferred technical solution of the present invention, the preparation method of the transition layer includes any one of electron beam method, magnetron sputtering method or reactive plasma deposition method.

[0033] Preferably, the preparation raw material of the transition layer is M x Sn 1-x O y material, where 0 < x ≤ 0.1, 1 ≤ y < 2, and M is a metal ion with an ionic radius less than 120 pm.

[0034] Preferably, the preparation method of the M x Sn 1-x O y material includes:

[0035] Mix a tin-based oxide and an M-based oxide, and then perform sintering to obtain the M x Sn 1-x O y material.

[0036] As a preferred embodiment of the present invention, the tin-based oxide includes SnO2 and / or SnO.

[0037] Preferably, the M-based oxide comprises MgO.

[0038] Preferably, the tin-based oxide comprises SnO2 and SnO, and the mass ratio of SnO2, SnO and M-based oxide is (0-19):(0-19):1, wherein the range of SnO2 selection "0-19" can be, for example, 0, 5, 10, 15 or 19, and the range of SnO selection "0-19" can be, for example, 0, 5, 10, 15 or 19.

[0039] Preferably, the sintering temperature is 700-1300℃, for example, 700℃, 800℃, 900℃, 1000℃, 1100℃, 1200℃ or 1300℃, and the time is 10-30min, for example, 10min, 20min, 25min or 30min.

[0040] In this invention, if the sintering temperature is too low, the elemental distribution within the raw material will be uneven. If the sintering temperature is too high, the resulting thin film will have poor electrical properties.

[0041] As a preferred technical solution of the present invention, the method for preparing the hole transport layer includes magnetron sputtering.

[0042] Preferably, the perovskite absorber layer is prepared by a solution method.

[0043] Preferably, the C 60 The preparation methods for the layer include thermal evaporation.

[0044] Preferably, the method for preparing the tin oxide layer includes ALD atomic layer deposition.

[0045] Preferably, the method for preparing the metal electrode includes thermal evaporation or magnetron sputtering.

[0046] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0047] (1) A hole transport layer with a thickness of 5-25 nm is prepared on the surface of the substrate by magnetron sputtering, and then annealed at 80-100℃ (e.g., 80℃, 90℃ or 100℃, etc.) for 10-20 min (e.g., 10 min, 15 min or 20 min, etc.).

[0048] (2) A perovskite wet film is coated on the hole transport layer, and then annealed at 100-200℃ for 15-25 min to form a perovskite absorption layer with a thickness of 400-600 nm.

[0049] (3) Sequentially deposit C layers with a thickness of 15-25 nm onto the perovskite absorber layer. 60 A layer of tin oxide with a thickness of 15-25 nm was formed, followed by electron beam chromatography with M... x Sn 1-x O y Using the material as a raw material, a transition layer with a thickness of 2-4 nm is deposited on the tin oxide layer. The specific parameters of the electron beam method include:

[0050] Vacuum degree ≤ 4×10 -4 Pa (for example, it could be 4 × 10) -4 Pa, 1×10 -4 Pa, 5×10 -5 Pa or 1×10 -5 The electron beam current is 100-120A (e.g., 100A, 110A or 120A), and the deposition time is 30-60s (e.g., 30s, 40s, 50s or 60s).

[0051] The M x Sn 1-x O y The material preparation steps include:

[0052] SnO2, SnO, and M-based oxides were mixed in a mass ratio of (0-19):(0-19):1, followed by ball milling and drying to form ceramic blanks. These blanks were then sintered in a vacuum atmosphere at 700-1300℃ for 10-30 minutes to obtain the M-based oxide. x Sn 1-x O y Material.

[0053] (4) A metal electrode with a thickness of 80-150 nm is deposited on the transition layer to obtain the inverted perovskite solar cell.

[0054] Thirdly, the present invention provides a photovoltaic module comprising an inverted perovskite solar cell as described in the first aspect.

[0055] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] This invention introduces a chemical formula of M x Sn 1-x O y The transition layer allows for a tighter, more conductive, and lower-resistance ohmic contact between the tin oxide layer and the metal electrode. It also increases the work function of the surface, causing the energy band to bend downwards, lowering the Schottky barrier, and forming an anti-blocking layer—a high-conductivity region. Therefore, the introduction of this transition layer significantly improves the electron transport efficiency and overall performance of the device, while ensuring that no additional fabrication complexity or cost is introduced, leading to greater economic benefits in large-scale practical applications. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the structure of the inverted perovskite solar cell prepared in Example 1 of this invention.

[0059] Figure 2 This is the work function spectrum of the transition layer in the inverted perovskite solar cell prepared in Example 5 of this invention.

[0060] Wherein, 1-substrate; 2-hole transport layer; 3-perovskite absorber layer; 4-electron transport layer; 5-transition layer; 6-metal electrode. Detailed Implementation

[0061] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0062] Example 1

[0063] This embodiment provides an inverted perovskite solar cell, the structural schematic of which is shown below. Figure 1 As shown, the inverted perovskite solar cell comprises, from bottom to top, a substrate 1, a hole transport layer 2, a perovskite absorber layer 3, an electron transport layer 4, a transition layer 5, and a metal electrode 6.

[0064] The electron transport layer 4 is sequentially stacked C along a direction away from the substrate. 60 Layer and tin oxide layer, C 60 The thickness of the layer is 20 nm, and the thickness of the tin oxide layer is 20 nm.

[0065] The chemical formula of the transition layer 5 is Mg. x Sn 1-x O yWhere x is 0.05, y is 1, the thickness of the transition layer 5 is 4nm, the light transmittance of the transition layer 5 in the wavelength range of 400-1200nm is 96.5%, and the light absorption rate is 3.1%.

[0066] The thickness ratio of the tin oxide layer, the transition layer, and the metal electrode 6 is 20:4:80.

[0067] The substrate 1 is FTO glass, the hole transport layer 2 is a 20nm thick nickel oxide layer, and the perovskite absorber layer 3 has the chemical formula Cs. 0.15 FA 0.85 MA 0.1 The PbI3 electrode has a thickness of 500 nm, and the metal electrode 6 is a silver electrode with a thickness of 110 nm.

[0068] This embodiment also provides a method for preparing the above-mentioned inverted perovskite solar cell, the method comprising the following steps:

[0069] (1) A nickel oxide layer with a thickness of 20 nm was prepared on the surface of FTO glass by magnetron sputtering and then annealed at 90 °C for 15 min.

[0070] (2) A perovskite wet film is spin-coated onto the nickel oxide layer, and then annealed at 150°C for 20 min to form a film with the chemical formula Cs. 0.15 FA 0.85 MA 0.1 PbI3 perovskite absorber layer 3.

[0071] (3) A C layer with a thickness of 20 nm was deposited on the perovskite absorber layer 3 by thermal evaporation. 60 A layer was first deposited, and then a 20 nm thick tin oxide layer was deposited using ALD atomic layer deposition, followed by electron beam deposition with Mg... 0.05 Sn 0.95 Using O material as the raw material, a transition layer 5 with a thickness of 4 nm is deposited on the tin oxide layer. The specific parameters of the electron beam method include:

[0072] Vacuum degree is 4×10 -4 Pa, electron beam current of 110 A, deposition time of 60 s.

[0073] The Mg 0.05 Sn 0.95 The preparation steps for O material include:

[0074] SnO2, SnO, and MgO powders were mixed in a mass ratio of 0:19:1, followed by ball milling and drying to form ceramic blanks. These blanks were then sintered in a vacuum tube furnace at 1000°C for 20 minutes to obtain the MgO powder. 0.05Sn 0.95 O material.

[0075] (4) A silver electrode with a thickness of 110 nm is deposited on the transition layer 5 by thermal evaporation to obtain the inverted perovskite solar cell.

[0076] Example 2

[0077] This embodiment provides an inverted perovskite solar cell, which, from bottom to top, includes a substrate, a hole transport layer, a perovskite absorber layer, an electron transport layer, a transition layer, and a metal electrode.

[0078] The electron transport layer is a tin oxide layer with a thickness of 25 nm.

[0079] The general chemical formula of the transition layer is Mg. 0.1 Sn 0.9 O 1.5 Where x is 0.1, y is 1.5, the thickness of the transition layer is 3nm, the light transmittance of the transition layer with a wavelength of 400-1200nm is 95.8%, and the light absorption rate is 4%.

[0080] The thickness ratio of the tin oxide layer, the transition layer, and the metal electrode is 25:3:90.

[0081] The substrate is FTO glass, the hole transport layer is a 20nm thick nickel oxide layer, and the perovskite absorber layer has the chemical formula Cs. 0.15 FA 0.85 MA 0.1 The metal electrode is a silver electrode with a thickness of 90 nm, and the PbI3 electrode has a thickness of 500 nm.

[0082] This embodiment also provides a method for preparing the above-mentioned inverted perovskite solar cell, the method comprising the following steps:

[0083] (1) A nickel oxide layer with a thickness of 20 nm was prepared on the surface of FTO glass by magnetron sputtering and then annealed at 80 °C for 20 min.

[0084] (2) A perovskite wet film is spin-coated onto the nickel oxide layer, and then annealed at 100°C for 25 min to form a film with the chemical formula Cs. 0.15 FA 0.85 MA 0.1 PbI3 perovskite absorber layer.

[0085] (3) A 25 nm thick tin oxide layer was deposited on the perovskite absorber layer using ALD atomic layer deposition, followed by electron beam deposition with Mg... 0.1 Sn 0.9 O1.5 Using the material as a raw material, a transition layer with a thickness of 3 nm is deposited on the tin oxide layer. The specific parameters of the electron beam method include:

[0086] Vacuum degree is 4×10 -4 Pa, electron beam current of 110 A, deposition time of 45 s.

[0087] The Mg 0.1 Sn 0.9 O 1.5 The material preparation steps include:

[0088] SnO2, SnO, and MgO powders were mixed in a mass ratio of 10:9:1, then ball-milled and dried to form ceramic blanks. These blanks were then sintered in a vacuum tube furnace at 700°C for 20 minutes to obtain the MgO powder. 0.1 Sn 0.9 O 1.5 Material.

[0089] (4) A silver electrode with a thickness of 90 nm is deposited on the transition layer by thermal evaporation to obtain the inverted perovskite solar cell.

[0090] Example 3

[0091] This embodiment provides an inverted perovskite solar cell, which, from bottom to top, includes a substrate, a hole transport layer, a perovskite absorber layer, an electron transport layer, a transition layer, and a metal electrode.

[0092] The electron transport layer is stacked sequentially along a direction away from the substrate. 60 Layer and tin oxide layer, C 60 The thickness of the layer is 15nm, and the thickness of the tin oxide layer is 15nm.

[0093] The general chemical formula of the transition layer is Mg. 0.05 Sn 0.95 O 1.95 Where x is 0.05, y is 1.95, the thickness of the transition layer is 2nm, the light transmittance of the transition layer with a wavelength of 400-1200nm is 96.1%, and the light absorption rate is 3.7%.

[0094] The thickness ratio of the tin oxide layer, the transition layer, and the metal electrode is 15:2:100.

[0095] The substrate is FTO glass, the hole transport layer is a 20nm thick nickel oxide layer, and the perovskite absorber layer has the chemical formula Cs. 0.15 FA 0.85 MA 0.1The metal electrode is a silver electrode with a thickness of 100 nm, and the PbI3 electrode has a thickness of 500 nm.

[0096] This embodiment also provides a method for preparing the above-mentioned inverted perovskite solar cell, the method comprising the following steps:

[0097] (1) A nickel oxide layer with a thickness of 20 nm was prepared on the surface of FTO glass by magnetron sputtering and then annealed at 100 °C for 10 min.

[0098] (2) A perovskite wet film is spin-coated onto the nickel oxide layer, and then annealed at 200°C for 15 min to form a film with the chemical formula Cs. 0.15 FA 0.85 MA 0.1 PbI3 perovskite absorber layer.

[0099] (3) A C layer with a thickness of 15 nm was deposited on the perovskite absorber layer using a thermal evaporation method. 60 A layer was first deposited, and then a 15 nm thick tin oxide layer was deposited using ALD atomic layer deposition, followed by electron beam deposition with Mg... 0.05 Sn 0.95 O 1.95 Using the material as a raw material, a transition layer with a thickness of 2 nm is deposited on the tin oxide layer. The specific parameters of the electron beam method include:

[0100] Vacuum degree is 4×10 -4 Pa, electron beam current of 110 A, deposition time of 30 s.

[0101] The Mg 0.05 Sn 0.95 O 1.95 The material preparation steps include:

[0102] SnO2, SnO, and MgO powders were mixed in a mass ratio of 19:0:1, followed by ball milling and drying to form ceramic blanks. These blanks were then sintered in a vacuum tube furnace at 1300°C for 20 minutes to obtain the MgO powder. 0.05 Sn 0.95 O 1.95 Material.

[0103] (4) A silver electrode with a thickness of 100 nm is deposited on the transition layer by thermal evaporation to obtain the inverted perovskite solar cell.

[0104] Example 4

[0105] The difference between this embodiment and Embodiment 1 is that the deposition parameters of the transition layer are adjusted so that the deposition time is 45s, thereby obtaining a transition layer with a thickness of 3nm.

[0106] The remaining preparation methods and parameters are consistent with those in Example 1.

[0107] Example 5

[0108] The difference between this embodiment and Embodiment 1 is that the deposition parameters of the transition layer are adjusted so that the deposition time is 30s, thereby obtaining a transition layer with a thickness of 2nm.

[0109] The remaining preparation methods and parameters are consistent with those in Example 1.

[0110] Figure 2 The work function spectrum of the transition layer in the inverted perovskite solar cell prepared in this embodiment is shown. As can be seen from the figure, the chemical formula is Mg. 0.05 Sn 0.95 The transition layer of O forms a homojunction with SnO2, with a work function of 4.43 eV, which is greater than the work function of silver electrode (4.26 eV). The energy band bends downward, reducing the Schottky barrier, thus resulting in a battery with excellent efficiency.

[0111] Example 6

[0112] The difference between this embodiment and embodiment 5 is that the mass ratio of SnO2, SnO and MgO powder in step (3) is adjusted to 0:9:1, so that the chemical formula of the transition layer is Mg. 0.1 Sn 0.9 O.

[0113] The remaining preparation methods and parameters are consistent with those in Example 5.

[0114] Example 7

[0115] The difference between this embodiment and embodiment 5 is that the mass ratio of SnO2, SnO and MgO powder in step (3) is adjusted to 10:9:1, so that the chemical formula of the transition layer is Mg. 0.1 Sn 0.9 O 1.5 .

[0116] The remaining preparation methods and parameters are consistent with those in Example 5.

[0117] Example 8

[0118] The difference between this embodiment and embodiment 5 is that the mass ratio of SnO2, SnO and MgO powder in step (3) is adjusted to 19:0:1, so that the chemical formula of the transition layer is Mg. 0.05 Sn 0.95 O 1.95 .

[0119] The remaining preparation methods and parameters are consistent with those in Example 5.

[0120] Example 9

[0121] The difference between this embodiment and embodiment 5 is that the thickness of the transition layer is 1 nm by adjusting the deposition time described in step (3).

[0122] The remaining preparation methods and parameters are consistent with those in Example 5.

[0123] Example 10

[0124] The difference between this embodiment and embodiment 5 is that the thickness of the transition layer is 5 nm by adjusting the deposition time described in step (3).

[0125] The remaining preparation methods and parameters are consistent with those in Example 5.

[0126] Example 11

[0127] The difference between this embodiment and embodiment 5 is that the thickness ratio of the tin oxide layer, the transition layer, and the metal electrode is 30:2:80.

[0128] The remaining preparation methods and parameters are consistent with those in Example 5.

[0129] Example 12

[0130] The difference between this embodiment and embodiment 5 is that the thickness ratio of the tin oxide layer, the transition layer, and the metal electrode is 10:4:80.

[0131] The remaining preparation methods and parameters are consistent with those in Example 5.

[0132] Example 13

[0133] The difference between this embodiment and embodiment 5 is that the sintering temperature in step (3) is 500°C.

[0134] The remaining preparation methods and parameters are consistent with those in Example 5.

[0135] Example 14

[0136] The difference between this embodiment and embodiment 5 is that the sintering temperature in step (3) is 1500℃.

[0137] The remaining preparation methods and parameters are consistent with those in Example 5.

[0138] Comparative Example 1

[0139] The difference between this comparative example and Example 5 is that no transition layer is set, that is, no transition layer deposition step is performed in step (3).

[0140] The remaining preparation methods and parameters are consistent with those in Example 5.

[0141] Comparative Example 2

[0142] The difference between this comparative example and Example 5 is that the mass ratio of SnO2, SnO, and MgO was adjusted so that the chemical formula of the transition layer was Mg. 0.15 Sn 0.85 O.

[0143] The remaining preparation methods and parameters are consistent with those in Example 5.

[0144] Comparative Example 3

[0145] The difference between this comparative example and Example 5 is that the chemical formula of the transition layer is Ba. 0.05 Sn 0.95 O.

[0146] The remaining preparation methods and parameters are consistent with those in Example 5.

[0147] Performance testing

[0148] The photoelectric performance of the inverted perovskite solar cells prepared in the above embodiments and comparative examples was tested. The conditions for the photoelectric performance test were: test area 1 cm². 2 AM1.5, 1000W / m 2 The temperature was 25±2℃. The test results are shown in Table 1.

[0149] Table 1

[0150]

[0151]

[0152] analyze:

[0153] As can be seen from the table above, this invention introduces a chemical formula of M... x Sn 1-x O y The transition layer allows for a tighter, more conductive, and lower-resistance ohmic contact between the tin oxide layer and the metal electrode. It also increases the work function of the surface, causing the energy band to bend downwards, lowering the Schottky barrier, and forming an anti-blocking layer, i.e., a high-conductivity region. Therefore, the introduction of this transition layer significantly improves the electron transport efficiency and overall performance of the device.

[0154] As can be seen from Examples 1-8, when the thickness of the transition layer is 2 nm and the chemical formula is Mg 0.05 Sn 0.95 Excellent battery performance can be achieved at 0°C, with an efficiency of up to 22.1%.

[0155] As can be seen from Examples 5 and 9-10, if the thickness of the transition layer is too thin, it may not be able to completely cover the surface of tin oxide, resulting in a decrease in battery efficiency; if the thickness of the transition layer is too thick, electrons will not be able to penetrate the tunnel junction, resulting in a decrease in battery efficiency.

[0156] As can be seen from Examples 5 and 11-12, if the thickness ratio of the tin oxide layer to the transition layer is too small, electrons will not be able to penetrate the tunnel junction, resulting in a decrease in battery efficiency; if the thickness ratio of the tin oxide layer to the transition layer is too large, the surface of the tin oxide layer may not be completely covered, resulting in a decrease in battery efficiency.

[0157] As can be seen from Examples 5 and 13-14, if the sintering temperature is too low, the element distribution in the raw material will be uneven, which is not conducive to improving battery efficiency; if the sintering temperature is too high, the electrical properties of the formed film will be poor, resulting in a decrease in battery efficiency.

[0158] As can be seen from Example 5 and Comparative Example 1, if a transition layer is not provided, the series resistance of the battery will increase, and the battery efficiency will not be improved.

[0159] As can be seen from Example 5 and Comparative Example 2, if the chemical formula of the transition layer is Mg 0.15 Sn 0.85 If O is present, excessive Mg doping will lead to energy level mismatch, preventing the achievement of ohmic contact and resulting in decreased battery efficiency.

[0160] As can be seen from Example 5 and Comparative Example 3, if the doped Mg ions are replaced with Ba ions with an ionic radius greater than 120 pm, the Ba ions may not be able to be incorporated, resulting in poor battery performance.

[0161] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A reverse perovskite solar cell, characterized in that, The inverted perovskite solar cell comprises, from bottom to top, a substrate, a hole transport layer, a perovskite absorber layer, an electron transport layer, a transition layer, and a metal electrode. The electron transport layer includes a tin oxide layer, and the chemical general formula of the transition layer is M x Sn 1-x O y , where 0 < x ≤ 0.1, 1 ≤ y < 2, and M is a metal ion with an ionic radius less than 120 pm.

2. The inverted perovskite solar cell according to claim 1, characterized in that, The thickness of the transition layer is 2-4 nm; Preferably, the thickness of the tin oxide layer is greater than the thickness of the transition layer; Preferably, the thickness ratio of the tin oxide layer, the transition layer, and the metal electrode is (15-25):(2-4):(80-120).

3. The inverted perovskite solar cell according to claim 1 or 2, characterized in that, The M includes Mg ions; Preferably, the metal electrode includes any one of a silver electrode, a copper electrode, or a gold electrode.

4. The inverted perovskite solar cell according to any one of claims 1-3, characterized in that, The light transmittance of the transition layer is ≥85%; The light absorption rate of the transition layer is ≤2%.

5. The inverted perovskite solar cell according to any one of claims 1-4, characterized in that, The hole transport layer includes a nickel oxide layer and / or a self-assembled molecular layer; Preferably, the self-assembled molecular layer includes any one or a combination of at least two of the following: Meo-2PACz layer, Meo-4PACz layer, 2PACz layer, 4PACz layer or 4PADCB layer; Preferably, the thickness of the hole transport layer is 5-25 nm; Preferably, the thickness of the perovskite absorber layer is 400-600 nm; Preferably, the electron transport layer further includes C 60 Layer, the C 60 The layers and the tin oxide layer are stacked sequentially in a direction away from the substrate.

6. A method for preparing an inverted perovskite solar cell as described in any one of claims 1-5, characterized in that, The preparation method includes the following steps: Hole transport layer, perovskite absorber layer, electron transport layer, transition layer and metal electrode are sequentially deposited on the substrate.

7. The preparation method according to claim 6, characterized in that, The method for preparing the transition layer includes any one of electron beam method, magnetron sputtering method or reactive plasma deposition method; Preferably, the raw material for preparing the transition layer is M x Sn 1-x O y material, where 0 < x ≤ 0.1, 1 ≤ y < 2, and M is a metal ion with an ionic radius less than 120 pm; Preferably, the M x Sn 1-x O y The methods for preparing the material include: Tin-based oxide and M-based oxide are mixed and then sintered to obtain the M. x Sn 1-x O y Material.

8. The preparation method according to claim 7, characterized in that, The tin-based oxide includes SnO2 and / or SnO; Preferably, the M-based oxide comprises MgO; Preferably, the tin-based oxide comprises SnO2 and SnO, and the mass ratio of SnO2, SnO and M-based oxide is (0-19):(0-19):1; Preferably, the sintering temperature is 700-1300℃ and the time is 10-30min.

9. The preparation method according to any one of claims 6-8, characterized in that, The preparation method includes the following steps: (1) A hole transport layer with a thickness of 5-25 nm was prepared on the surface of the substrate by magnetron sputtering, and then annealed at 80-100℃ for 10-20 min. (2) A perovskite wet film is coated on the hole transport layer, and then annealed at 100-200℃ for 15-25 min to form a perovskite absorption layer with a thickness of 400-600 nm. (3) Sequentially deposit C layers with a thickness of 15-25 nm onto the perovskite absorber layer. 60 A layer of tin oxide with a thickness of 15-25 nm was formed, followed by electron beam chromatography with M... x Sn 1-x O y Using the material as a raw material, a transition layer with a thickness of 2-4 nm is deposited on the tin oxide layer. The specific parameters of the electron beam method include: Vacuum degree ≤ 4 × 10 -4 Pa, electron beam current of 100-120A, deposition time of 30-60s; The M x Sn 1-x O y The material preparation steps include: SnO2, SnO, and M-based oxides were mixed in a mass ratio of (0-19):(0-19):1, followed by ball milling and drying to form ceramic blanks. These blanks were then sintered in a vacuum atmosphere at 700-1300℃ for 10-30 minutes to obtain the M-based oxide. x Sn 1-x O y Material; (4) A metal electrode with a thickness of 80-150 nm is deposited on the transition layer to obtain the inverted perovskite solar cell.

10. A photovoltaic module, characterized in that, The photovoltaic module includes the inverted perovskite solar cell as described in any one of claims 1-5.

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