A perovskite solar cell, its fabrication method, and a tandem cell

Abstract

This application relates to the field of solar cell technology, providing a perovskite solar cell, its fabrication method, and a tandem solar cell. The perovskite solar cell includes a glass substrate, a conductive layer, a first contact layer, a perovskite light-absorbing layer, a second contact layer, and an electrode, stacked sequentially. The conductive layer comprises multiple conductive films, with the oxygen content decreasing along the direction from the glass substrate to the electrode. This improves the performance of the conductive layer, making it more compatible with the other layers of the perovskite solar cell, thereby increasing the photoelectric conversion efficiency of the perovskite solar cell.

Description

Technical Field

[0001] This application belongs to the field of solar cell technology, and particularly relates to a perovskite solar cell, its fabrication method, and a tandem cell. Background Technology

[0002] In related technologies, perovskite solar cells typically employ magnetron sputtering to directly deposit a conductive layer onto the substrate. However, the resistivity, transmittance, and carrier concentration of this conductive layer cannot match those of other layers in the perovskite solar cell, resulting in low photoelectric conversion efficiency. Therefore, designing the conductive layer of a perovskite solar cell to improve its photoelectric conversion efficiency has become a pressing issue. Summary of the Invention

[0003] This application provides a perovskite solar cell, a method for fabricating the same, and a tandem cell, aiming to solve the problem of how to design the conductive layer of a perovskite solar cell to improve photoelectric conversion efficiency.

[0004] In a first aspect, the perovskite solar cell provided in this application includes a glass substrate, a conductive layer, a first contact layer, a perovskite light-absorbing layer, a second contact layer, and an electrode stacked sequentially; the conductive layer includes multiple conductive films, and the oxygen content of the multiple conductive films decreases along the direction from the glass substrate to the electrode.

[0005] Optionally, the thickness of the conductive layer ranges from 170 nm to 185 nm.

[0006] Optionally, the conductive layer comprises three conductive films, namely a first conductive film, a second conductive film, and a third conductive film, along the direction from the glass substrate to the electrode, wherein the oxygen content of the first conductive film, the second conductive film, and the third conductive film decreases in that order.

[0007] Optionally, the thickness of the first conductive film is in the range of 80nm-85nm; and / or, the thickness of the second conductive film is in the range of 50nm-55nm; and / or, the thickness of the third conductive film is in the range of 40nm-45nm.

[0008] Optionally, the electrode is multilayered, and the oxygen content of the multilayered electrodes decreases sequentially along the direction from the glass substrate to the electrode.

[0009] Secondly, the method for fabricating a perovskite solar cell provided in this application includes:

[0010] A conductive layer is formed by sequentially depositing multiple conductive films with decreasing oxygen content on a glass substrate.

[0011] A first contact layer, a perovskite light-absorbing layer, a second contact layer, and an electrode are sequentially deposited on the conductive layer.

[0012] Optionally, the conductive layer comprises three conductive films, wherein multiple conductive films with decreasing oxygen content are sequentially deposited on a glass substrate to form the conductive layer, including:

[0013] A first conductive film is deposited on a glass substrate;

[0014] A second conductive film is deposited on the first conductive film;

[0015] A third conductive film is deposited on the second conductive film, wherein the oxygen content of the first conductive film, the second conductive film, and the third conductive film decreases in that order.

[0016] Optionally, a first contact layer, a perovskite light-absorbing layer, a second contact layer, and an electrode are sequentially deposited on the conductive layer, including:

[0017] The first contact layer is deposited on the conductive layer;

[0018] Deposit the perovskite light-absorbing layer on the first contact layer;

[0019] A second contact layer is deposited on the perovskite light-absorbing layer;

[0020] The electrode is deposited on the second contact layer.

[0021] Thirdly, the perovskite solar cell provided in this application is fabricated using any of the methods described above.

[0022] Fourthly, the tandem solar cell provided in this application includes any of the perovskite solar cells described above.

[0023] In the perovskite solar cells and their fabrication methods and tandem cells of the embodiments of this application, since the oxygen content of the multilayer conductive films decreases along the direction from the glass substrate to the electrode, the performance of the conductive layer can be improved, making the conductive layer more compatible with the other film layers of the perovskite solar cell, thereby improving the photoelectric conversion efficiency of the perovskite solar cell. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a perovskite solar cell according to an embodiment of this application;

[0025] Figure 2 This is a schematic flowchart of a method for fabricating a perovskite solar cell according to an embodiment of this application;

[0026] Figure 3 This is a schematic flowchart of a method for fabricating a perovskite solar cell according to an embodiment of this application;

[0027] Figure 4 This is a schematic flowchart of a method for fabricating a perovskite solar cell according to an embodiment of this application;

[0028] Figure 5 This is a schematic diagram of the structure of the stacked battery according to an embodiment of this application.

[0029] Explanation of key component symbols:

[0030] The components include a tandem solar cell 100, a crystalline silicon solar cell 20, a perovskite solar cell 10, a glass substrate 11, a conductive layer 12, a first conductive film 121, a second conductive film 122, a third conductive film 123, a first contact layer 13, a perovskite light-absorbing layer 14, a second contact layer 15, and an electrode 16. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0032] Please see Figure 1 The perovskite solar cell 10 of this application embodiment includes a glass substrate 11, a conductive layer 12, a first contact layer 13, a perovskite light-absorbing layer 14, a second contact layer 15 and an electrode 16 stacked sequentially; the conductive layer 12 includes multiple conductive films, and the oxygen content of the multiple conductive films decreases along the direction from the glass substrate 11 to the electrode 16.

[0033] In the perovskite solar cell 10 of this application embodiment, since the oxygen content of the multilayer conductive film decreases along the direction from the glass substrate 11 to the electrode 16, the performance of the conductive layer 12 can be improved, making the conductive layer 12 more compatible with the other film layers of the perovskite solar cell 10, thereby improving the photoelectric conversion efficiency of the perovskite solar cell 10.

[0034] Please see Figure 1 Optionally, the glass substrate 11 may include a transparent glass substrate 11. Specifically, the transmittance of the glass substrate 11 may be greater than 90%, for example, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%. Thus, the high transmittance of the glass substrate 11 allows more sunlight to enter the perovskite solar cell 10, which is beneficial for improving photoelectric conversion efficiency. Preferably, the transmittance of the glass substrate 11 is 92%.

[0035] Specifically, the glass substrate 11 includes one or more of float glass, patterned glass, tempered glass, anti-reflective glass, PET, PEN, PEI, and PMMA. Thus, a variety of glass substrates 11 are provided to facilitate selection based on actual production needs.

[0036] For example, substrate 11 may include float glass; or, for instance, glass substrate 11 may include float glass, patterned glass, and tempered glass; or, for still others, glass substrate 11 may include anti-reflective glass, PET, PEN, and PMMA. No specific form of glass substrate 11 is limited here.

[0037] Specifically, the glass substrate 11 can be cleaned. Further, it can be ultrasonically cleaned sequentially using detergent, deionized water, acetone, and ethanol; the ultrasonically cleaned glass substrate 11 can be purged with high-purity nitrogen; and the high-purity nitrogen-purged glass substrate 11 can be cleaned using an oxygen plasma cleaner. This ensures the glass substrate 11 is transparent and clean, preventing impurities from affecting the subsequent film preparation.

[0038] Furthermore, the duration of ultrasonic cleaning ranges from 15 to 25 minutes, for example, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, and 25 minutes. Preferably, the duration of ultrasonic cleaning is 20 minutes. This results in better ultrasonic cleaning performance.

[0039] Furthermore, the oxygen plasma cleaning time ranges from 5 to 15 minutes. For example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, and 15 minutes. Preferably, the oxygen plasma cleaning time is 10 minutes. This results in a better oxygen plasma cleaning effect.

[0040] Optionally, the thickness of the conductive layer 12 ranges from 170nm to 185nm. For example, it can be 170nm, 173nm, 175nm, 180nm, 182nm, or 185nm. This ensures that the conductive layer 12 is within a suitable range, resulting in better conductivity.

[0041] Preferably, the thickness of the conductive layer 12 is 180 nm. In this way, the conductive layer 12 has the best conductivity.

[0042] Please see Figure 1Optionally, the conductive layer 12 includes three conductive films: a first conductive film 121, a second conductive film 122, and a third conductive film 123, which are arranged along the direction from the glass substrate 11 to the electrode 16. The oxygen content of the first conductive film 121, the second conductive film 122, and the third conductive film 123 decreases in that order. This improves the performance of the conductive layer 12, making it more compatible with the other films of the perovskite solar cell 10, thereby increasing the photoelectric conversion efficiency of the perovskite solar cell 10.

[0043] It is understandable that the first conductive film 121 has a high oxygen content. More O2 reduces oxygen vacancies in the first conductive film 121 and increases its crystallinity. The surface of the film near the glass substrate 11 has a relatively large roughness; therefore, the first conductive film 121 needs to have high crystallinity to reduce the possibility of carrier recombination. The second conductive film 122 has a moderate oxygen content, balancing crystallinity, carrier mobility, and resistivity. The third conductive film 123 has a low but not excessively low oxygen content, ensuring high carrier concentration and migration rate without affecting crystallinity.

[0044] It is understood that in other embodiments, the conductive layer 12 may also include 2, 4, 5, or other numbers of conductive films. The specific number of conductive films in the conductive layer 12 is not limited here.

[0045] Optionally, the refractive indices of the first conductive film 121, the second conductive film 122, and the third conductive film 123 increase sequentially. This creates a refractive index gradient, resulting in gradient extinction, which is beneficial for improving the photoelectric conversion efficiency of the battery.

[0046] Optionally, the thickness of the first conductive film 121 ranges from 80nm to 85nm. For example, it can be 80nm, 81nm, 82nm, 83nm, 84nm, or 85nm. This ensures that the thickness of the first conductive film 121 is within a suitable range, avoiding poor conductivity due to excessive thickness and high cost due to excessive thickness. Preferably, the thickness of the first conductive film 121 is 82.5nm. This achieves the best overall performance.

[0047] Optionally, the thickness of the second conductive film 122 is in the range of 50nm-55nm. For example, it can be 50nm, 51nm, 52nm, 53nm, 54nm, or 55nm. This ensures that the thickness of the second conductive film 122 is within a suitable range, avoiding poor conductivity due to excessive thickness and high cost due to excessive thickness. Preferably, the thickness of the second conductive film 122 is 52.5nm. This achieves the best overall performance.

[0048] Optionally, the thickness of the third conductive film 123 ranges from 40nm to 50nm. For example, it can be 40nm, 41nm, 42nm, 43nm, 44nm, 45nm, 46nm, 47nm, 48nm, 49nm, or 50nm. This ensures the thickness of the third conductive film 123 is within a suitable range, avoiding poor conductivity due to excessive thickness and high cost due to excessive thickness. Preferably, the thickness of the third conductive film 123 is 45nm. This achieves the best overall performance.

[0049] Optionally, the conductive layer 12 includes a transparent conductive oxide (TCO). In this way, the TCO can effectively collect the current of the perovskite solar cell 10, ensuring the normal operation of the perovskite solar cell 10. Furthermore, the TCO has high transmittance and anti-reflection properties, which can reduce the loss of sunlight. This is beneficial for improving photoelectric conversion efficiency.

[0050] In this embodiment, the first conductive film 121, the second conductive film 122, and the third conductive film 123 are all TCO (Total Conductive Occurrence). It can be understood that in other embodiments, only one of the first conductive film 121, the second conductive film 122, and the third conductive film 123 may be TCO, or only one of the first conductive film 121, the second conductive film 122, and the third conductive film 123 may not be TCO.

[0051] Specifically, the transparent conductive oxide includes one or more of the following: fluorine-doped tin oxide (FTO), indium zinc oxide (IZO), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), aluminum-doped tin oxide (ATO), and indium-doped gallium oxide (IGO). Preferably, the first conductive film 121, the second conductive film 122, and the third conductive film 123 are all ITO.

[0052] Please see Figure 1 The first contact layer 13 is disposed on the conductive layer 12. Specifically, the first contact layer 13 is an electron transport layer. In this way, electrons excited by sunlight can be transported in a timely manner through the first contact layer 13, avoiding the accumulation of electrons that would affect the lifetime of the perovskite solar cell 10. Moreover, this can also block holes and reduce hole-electron recombination.

[0053] It is understood that when the first contact layer 13 is an electron transport layer, the second contact layer 15 is a hole transport layer. In other embodiments, the first contact layer 13 may be a hole transport layer and the second contact layer 15 may be an electron transport layer.

[0054] Specifically, the thickness of the first contact layer 13 ranges from 10nm to 100nm. For example, it can be 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, or 100nm. This thickness of the first contact layer 13 is within a suitable range, resulting in better carrier transport. Preferably, the thickness of the first contact layer 13 is 20nm. This provides the best carrier transport performance.

[0055] Specifically, the first contact layer 13 may include one or more of C60, PCBM, titanium oxide (TiO2), zinc oxide (ZnO), zinc stannate (ZnSnO4), or tin oxide (SnO2).

[0056] Furthermore, the first contact layer 13 includes a SnO2 layer. A SnO2 precursor solution can be obtained by first mixing a SnO2 dispersion and deionized water at a volume ratio of 1:7; then, it can be deposited on the third conductive layer 122 using a slot coating method to obtain the SnO2 layer. In this way, the first contact layer 13 can be fabricated conveniently and efficiently.

[0057] Please see Figure 1 The perovskite light-absorbing layer 14 is located on the side of the first contact layer 13 away from the conductive layer 12.

[0058] Specifically, the perovskite light-absorbing layer 14 has an ABX3 crystal structure, where A is Cs. + CH(NH2)2 + CH3NH3 + C(NH2)3 + One or more of them, where B is Pb 2+ Sn 2+ At least one of them, wherein X is Br - I - Cl - One or more of these. This results in better light absorption of the perovskite light-absorbing layer 14, which is beneficial for improving photoelectric conversion efficiency.

[0059] For example, A is Cs + B is Pb 2+ X is Br - For example, A is Cs + and CH(NH2)2 + B is Pb 2+ X is Br -For example, A is Cs + B is Pb 2+ and Sn 2+ X is Br - For example, A is Cs + B is Pb 2+ X is Br - and I - For example, A is CH3NH3 + and C(NH2)3 + B is Pb 2+ X is I - and Cl - For example, A is Cs + CH(NH2)2 + CH3NH3 + and C(NH2)3 + B is Pb 2+ and Sn 2+ X can be Br-, I-, or Cl-.

[0060] Specifically, the thickness of the perovskite light-absorbing layer 14 ranges from 400 nm to 500 nm. For example, it can be 400 nm, 402 nm, 421 nm, 430 nm, 445 nm, 450 nm, 476 nm, 485 nm, 498 nm, or 500 nm. This thickness is within a suitable range, resulting in better light absorption. Preferably, the thickness of the perovskite light-absorbing layer 14 is 450 nm.

[0061] Specifically, the perovskite light-absorbing layer 14 can be black.

[0062] Specifically, the perovskite light-absorbing layer 14 can be deposited using spin coating, slot-die coating, doctor blading, or chemical vapor deposition (CVD).

[0063] Specifically, a perovskite preparation solution can be prepared; the solution is coated onto the first contact layer 13 to obtain a perovskite wet film layer; the perovskite wet film layer is annealed to form a perovskite light-absorbing layer 14. In this way, the perovskite light-absorbing layer 14 can be formed conveniently and efficiently.

[0064] Furthermore, the perovskite preparation solution can be a solution of CH3NH3I and PbI2 dissolved in DMF and DMSO.

[0065] Furthermore, the molar ratio of CH3NH3I to PbI2 ranges from 1:(1.005-1.015). Examples include 1:1.005, 1:1.006, 1:1.007, 1:1.008, 1:1.009, 1:1.01, 1:1.011, 1:1.012, 1:1.013, 1:1.014, and 1:1.015. Preferably, the molar ratio of CH3NH3I to PbI2 is 1:1.01.

[0066] Further, the volume ratio of DMF to DMSO is 3:(6.5-7.5). For example, it is 3:6.5, 3:6.6, 3:6.7, 3:6.8, 3:6.9, 3:7, 3:7.1, 3:7.2, 3:7.3, 3:7.4, or 3:7.5. Preferably, the volume ratio of DMF to DMSO is 3:7.

[0067] Furthermore, after dissolving CH3NH3I and PbI2 in a solution of DMF and DMSO, the solution can be stirred. This ensures that CH3NH3I and PbI2 are fully dissolved, which is beneficial for improving the quality of the perovskite light-absorbing layer 14.

[0068] Furthermore, the stirring time of the solution ranges from 1.8h to 2.2h. For example, 1.8h, 1.9h, 2.0h, 2.1h, and 2.2h. This ensures that the stirring time is within a suitable range, allowing CH3NH3I and PbI2 to dissolve completely. Preferably, the stirring time is 2h.

[0069] Furthermore, the temperature range of the stirred solution is 65℃-75℃. For example, 65℃, 66℃, 67℃, 68℃, 69℃, 70℃, 71℃, 72℃, 73℃, 74℃, and 75℃. This ensures the temperature of the stirred solution is within a suitable range, allowing CH3NH3I and PbI2 to dissolve fully. Preferably, the temperature of the stirred solution is 70℃.

[0070] Furthermore, a slot coating process can be used to coat the solution onto the first contact layer 13. This results in a faster coating speed and fewer defects in the perovskite wet film layer.

[0071] Furthermore, the substrate coated with the perovskite wet film layer can be heated and dried for 8-12 minutes. For example, 8 minutes, 9 minutes, 10 minutes, 11 minutes, or 12 minutes. In this way, the perovskite wet film layer is formed into the perovskite light-absorbing layer 14. Preferably, the heating and drying is performed for 10 minutes.

[0072] Please see Figure 1The second contact layer 15 is located on the side of the perovskite light absorption layer 14 opposite to the first contact layer 13. Specifically, the second contact layer 15 is a hole transport layer, which includes one or more of NiOx film, Spiro-oMeTad film, CuPc film, CuSCN film and PTAA film.

[0073] For example, the hole transport layer may include a NiOx film; or it may include both a NiOx film and a PTAA film; or it may include a NiOx film, a Spiro-oMeTad film, a CuSCN film, and a PTAA film. In this way, holes excited by sunlight can be transported in a timely manner through the second contact layer 15, preventing hole accumulation from affecting the lifetime of the perovskite solar cell 10. Furthermore, this also blocks electrons, reducing hole-electron recombination. Preferably, the hole transport layer includes a Spiro-oMeTad film.

[0074] Specifically, the thickness of the second contact layer 15 ranges from 10nm to 100nm. For example, it can be 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, or 100nm. This thickness of the second contact layer 15 is within a suitable range, resulting in better carrier transport. Preferably, the thickness of the second contact layer 15 is 20nm.

[0075] Specifically, a wet film of the second contact layer 15 can be coated on the perovskite light-absorbing layer 14; then the wet film of the second contact layer 15 can be dried by heating. In this way, the second contact layer 15 can be prepared conveniently and efficiently.

[0076] Furthermore, a slot coating process can be used to coat the wet film layer of the second contact layer 15 onto the perovskite light-absorbing layer 14. In this way, the coating speed is faster and there are fewer defects in the wet film layer of the second contact layer 15.

[0077] Furthermore, the substrate coated with the wet film layer of the second contact layer 15 can be heated and dried for 8-12 minutes. For example, 8 minutes, 9 minutes, 10 minutes, 11 minutes, or 12 minutes. In this way, the wet film layer of the second contact layer 15 is formed into the second contact layer 15. Preferably, the heating and drying is performed for 10 minutes.

[0078] Please see Figure 1 Electrode 16 is located on the side of the second contact layer 15 away from the perovskite light absorption layer 14.

[0079] Specifically, the thickness of electrode 16 ranges from 70nm to 85nm. For example, it can be 70nm, 72nm, 75nm, 78nm, 80nm, 81nm, 82nm, 83nm, 84nm, or 85nm. This thickness of electrode 16 is within a suitable range, resulting in better conductivity. Preferably, the thickness of electrode 16 is 80nm.

[0080] In this embodiment, electrode 16 is ITO.

[0081] It is understood that in other embodiments, electrode 16 may be other TCOs. Explanations and descriptions of this part can be found above, and will not be repeated here to avoid redundancy.

[0082] Optionally, the electrode 16 is multilayered, and the oxygen content of the multilayer electrode decreases sequentially along the direction from the glass substrate to the electrode 16.

[0083] Specifically, along the direction from the glass substrate to the electrode 16, there are a first electrode layer, a second electrode layer, and a third electrode layer, with the oxygen content decreasing sequentially. This improves the performance of the electrode 16.

[0084] Furthermore, the thickness of the first electrode layer ranges from 40nm to 45nm. For example, it can be 40nm, 41nm, 42nm, 43nm, 44nm, or 45nm. This ensures the thickness of the first electrode layer is within a suitable range, avoiding poor conductivity due to excessive thickness and high cost due to excessive thickness. Preferably, the thickness of the first electrode layer is 42.5nm. This achieves the best overall performance.

[0085] Furthermore, the thickness of the second electrode layer ranges from 20nm to 25nm. For example, it can be 20nm, 21nm, 22nm, 23nm, 24nm, or 25nm. This ensures the thickness of the second electrode layer is within a suitable range, avoiding poor conductivity due to excessive thickness and high cost due to excessive thickness. Preferably, the thickness of the second electrode layer is 22.5nm. This achieves the best overall performance.

[0086] Furthermore, the thickness of the third electrode layer ranges from 10nm to 15nm. For example, it can be 10nm, 11nm, 12nm, 13nm, 14nm, or 15nm. This ensures the thickness of the third electrode layer is within a suitable range, avoiding poor conductivity due to excessive thickness and high cost due to excessive thickness. Preferably, the thickness of the third electrode layer is 15nm. This achieves the best overall performance.

[0087] Specifically, along the direction from the glass substrate to the electrode 16, the oxygen content of the first electrode layer, the second electrode layer, and the third electrode layer decreases.

[0088] The O2 and Ar gas flow rate ratio used in the first electrode layer is (3.6-4.4) / 40. For example, ratios such as 3.6 / 40, 3.7 / 40, 3.8 / 40, 3.9 / 40, 4 / 40, 4.1 / 40, 4.2 / 40, 4.3 / 40, and 4.4 / 40 are used. Preferably, the O2 and Ar gas flow rate ratio used in the first electrode layer is 4 / 40. This higher O2 and Ar gas flow rate ratio reduces oxygen vacancies in the first electrode layer, thus increasing its crystallinity.

[0089] The O2 and Ar gas flow rate ratio used in the second electrode layer is (2.6-3.4) / 40. Examples include 2.6 / 40, 2.7 / 40, 2.8 / 40, 2.9 / 40, 3 / 40, 3.1 / 40, 3.2 / 40, 3.3 / 40, and 3.4 / 40. Preferably, the O2 and Ar gas flow rate ratio used in the second electrode layer is 3 / 40. This provides a suitable O2 and Ar gas flow rate ratio, balancing crystallinity, carrier mobility, and resistivity.

[0090] The O2 and Ar gas flow rate ratio used in the third electrode layer is (0.6-1.4) / 40. For example, ratios such as 0.6 / 40, 0.7 / 40, 0.8 / 40, 0.9 / 40, 1 / 40, 1.1 / 40, 1.2 / 40, 1.3 / 40, and 1.4 / 40 are used. Preferably, the O2 and Ar gas flow rate ratio used in the third electrode layer is 1 / 40. This O2 and Ar gas flow rate ratio is relatively low but not excessively low, ensuring a high carrier concentration and migration rate in the third conductive film 123 without affecting crystallinity. It is understood that an excessively low O2 and Ar gas flow rate ratio, such as 0 / 40, would affect the crystallinity of the ITO film. Appropriately increasing the oxygen content does not affect its crystallinity, and the lower oxygen content results in a large number of oxygen vacancies in the ITO film, leading to a higher carrier concentration and migration rate.

[0091] Thus, through the combined effect of the first electrode layer, the second electrode layer, and the third electrode layer, electrode 16 possesses excellent crystallinity and conductivity.

[0092] It is understood that in other embodiments, electrode 16 may include a metal electrode 16. Specifically, the metal electrode 16 may be made of one or more materials selected from silver (Ag), gold (Au), aluminum (Al), copper (Cu), molybdenum (Mo), tungsten (W), nickel (Ni), magnesium (Mg), tin (Sn), and tantalum (Ta). Further, when the metal electrode 16 is made of multiple materials selected above, the metal electrode 16 may comprise multiple groups, each group of metal electrodes 16 being made of one of the aforementioned materials; the metal electrode 16 may be made of an alloy of multiple materials selected above; or a portion of the metal electrode 16 may be made of an alloy of multiple materials selected above, while the remaining metal electrodes 16 may comprise one or more groups, each group of metal electrodes 16 being made of one of the aforementioned materials. Preferably, the metal electrode 16 is a silver electrode 16.

[0093] Please note that electrode 16 may include metal electrode 16 and TCO.

[0094] Specifically, electrode 16 can be fabricated using chemical vapor deposition (CVD) or thermal evaporation processes. This results in a higher quality electrode 16.

[0095] Please see Figure 2 The method for fabricating the perovskite solar cell 10 according to an embodiment of this application includes:

[0096] Step S11: Sequentially deposit multiple conductive films with decreasing oxygen content on the glass substrate 11 to form conductive layer 12;

[0097] Step S12: Sequentially deposit the first contact layer 13, the perovskite light absorption layer 14, the second contact layer 15, and the electrode 16 on the conductive layer 12.

[0098] The fabrication method of the perovskite solar cell 10 in this application embodiment improves the performance of the conductive layer 12 by decreasing the oxygen content of the multilayer conductive film along the direction from the glass substrate 11 to the electrode 16. This makes the conductive layer 12 more compatible with the other films of the perovskite solar cell 10, thereby improving the photoelectric conversion efficiency of the perovskite solar cell 10.

[0099] Specifically, in step S11, a multilayer conductive film can be deposited using a stepwise vapor deposition method. This results in better uniformity of the conductive film and allows for more accurate control of the film thickness, ensuring that each conductive film reaches its target thickness.

[0100] Specifically, in step S11, a multilayer conductive film can be deposited by magnetron sputtering. The properties of the multilayer conductive film can be changed by introducing different amounts of oxygen into the vacuum chamber. The crystallization performance and carrier migration capability of the multilayer conductive film can be adjusted by optimizing the gas flow ratio of O2 and Ar.

[0101] In this application, the multilayer conductive film is ITO. ITO belongs to the n-type semiconductor thin film, and its charge carriers mainly come from Sn. 4+ In replacement of indium oxide 3+ One electron is released, and a second electron is released from the oxygen vacancy in the reduced indium oxide itself.

[0102] The first conductive film 121 uses an O2 to Ar gas flow rate ratio of (3.6-4.4) / 40. For example, ratios such as 3.6 / 40, 3.7 / 40, 3.8 / 40, 3.9 / 40, 4 / 40, 4.1 / 40, 4.2 / 40, 4.3 / 40, and 4.4 / 40 are used. Preferably, the O2 to Ar gas flow rate ratio used in the first conductive film 121 is 4 / 40. This higher O2 to Ar gas flow rate ratio reduces oxygen vacancies in the first conductive film 121 and increases its crystallinity. Since the film surface near the glass substrate 11 has a higher roughness, the first conductive film 121 needs to have higher crystallinity to reduce the possibility of carrier recombination.

[0103] The second conductive film 122 uses an O2 to Ar gas flow rate ratio of (2.6-3.4) / 40. For example, ratios such as 2.6 / 40, 2.7 / 40, 2.8 / 40, 2.9 / 40, 3 / 40, 3.1 / 40, 3.2 / 40, 3.3 / 40, and 3.4 / 40 are used. Preferably, the O2 to Ar gas flow rate ratio used in the second conductive film 122 is 3 / 40. This provides a suitable O2 to Ar gas flow rate ratio, balancing crystallinity, carrier mobility, and resistivity.

[0104] The O2 and Ar gas flow rate ratio used in the third conductive film 123 is (0.6-1.4) / 40. For example, ratios such as 0.6 / 40, 0.7 / 40, 0.8 / 40, 0.9 / 40, 1 / 40, 1.1 / 40, 1.2 / 40, 1.3 / 40, and 1.4 / 40 are used. Preferably, the O2 and Ar gas flow rate ratio used in the third conductive film 123 is 1 / 40. This O2 and Ar gas flow rate ratio is relatively low but not excessively low, achieving a high carrier concentration and migration rate in the third conductive film 123 without affecting crystallinity. It is understood that an excessively low O2 and Ar gas flow rate ratio, such as 0 / 40, would affect the crystallinity of the ITO film. Appropriately increasing the oxygen content does not affect its crystallinity, and the lower oxygen content results in a large number of oxygen vacancies in the ITO film, leading to a higher carrier concentration and migration rate.

[0105] Thus, through the combined effect of the first conductive film 121, the second conductive film 122 and the third conductive film 123, the conductive layer 12 possesses excellent crystallinity and conductivity.

[0106] Specifically, before step S11, the glass substrate 11 can be cleaned. Further, it can be ultrasonically cleaned sequentially using detergent, deionized water, acetone, and ethanol; the ultrasonically cleaned glass substrate 11 is then purged with high-purity nitrogen; and finally, the high-purity nitrogen-purged glass substrate 11 is cleaned using an oxygen plasma cleaner. This ensures the glass substrate 11 is transparent and clean, preventing impurities from affecting the subsequent film preparation.

[0107] Please see Figure 3 Optionally, the conductive layer 12 includes three conductive films, and step S11 includes:

[0108] Step S111: Deposit a first conductive film 121 on the glass substrate 11;

[0109] Step S112: Deposit a second conductive film 122 on the first conductive film 121;

[0110] Step S113: Deposit a third conductive film 123 on the second conductive film 122, wherein the oxygen content of the first conductive film 121, the second conductive film 122 and the third conductive film 123 decreases in that order.

[0111] Thus, three conductive films with decreasing oxygen content are sequentially deposited on the glass substrate 11 to form the conductive layer 12, resulting in better performance of the conductive layer 12.

[0112] It is understood that in other embodiments, two, four, five, or other numbers of conductive films may be sequentially deposited on the glass substrate 11. The specific number of conductive films deposited sequentially is not limited here.

[0113] Specifically, the first conductive film 121, the second conductive film 122, and the third conductive film 123 can all be TCO (Total Coefficient of Materials). This eliminates the need to change materials during the deposition process, thus improving efficiency.

[0114] Please see Figure 4 Optionally, step S12 includes:

[0115] Step S121: Deposit a first contact layer 13 on the conductive layer 12;

[0116] Step S123: Deposit a perovskite light-absorbing layer 14 on the first contact layer 13;

[0117] Step S124: Deposit a second contact layer 15 on the perovskite light-absorbing layer 14;

[0118] Step S125: Deposit electrode 16 on second contact layer 15.

[0119] In this way, a first contact layer 13, a perovskite light-absorbing layer 14, a second contact layer 15 and an electrode 16 are sequentially deposited on the conductive layer 12, thereby fabricating a perovskite solar cell 10.

[0120] Specifically, in step S121, the dispersion and deionized water are first mixed to obtain a precursor solution; then, the precursor solution is deposited on the conductive layer 12 using a slot coating method to obtain the first contact layer 13. In this way, the first contact layer 13 can be fabricated conveniently and efficiently.

[0121] Further, the volume ratio of the dispersion to deionized water is 1:(6-8). For example, it is 1:6, 1:62, 1:65, 1:68, 1:7, 1:61, 1:63, 1:65, 1:69, or 1:8. Preferably, the volume ratio of the dispersion to deionized water is 1:7.

[0122] Specifically, in step S123, the perovskite light-absorbing layer 14 can be deposited using spin coating, slot-die coating, doctor blading, or chemical vapor deposition (CVD). Explanations and descriptions of this part can be found above; to avoid redundancy, they will not be repeated here.

[0123] Specifically, in step S124, a wet film layer of the second contact layer 15 can be coated on the perovskite light-absorbing layer 14; then, the wet film layer of the second contact layer 15 is dried by heating. This allows for convenient and efficient preparation of the second contact layer 15. Explanations and descriptions of this part can be found above; to avoid redundancy, they will not be repeated here.

[0124] Specifically, in step S125, electrode 16 can be fabricated using chemical vapor deposition (CVD) or thermal evaporation processes. This results in a higher quality electrode 16.

[0125] The perovskite solar cell 10 of this application embodiment is manufactured using any of the methods described above.

[0126] In the perovskite solar cell 10 of this application embodiment, since the oxygen content of the multilayer conductive film decreases along the direction from the glass substrate 11 to the electrode 16, the performance of the conductive layer 12 can be improved, making the conductive layer 12 more compatible with the other film layers of the perovskite solar cell 10, thereby improving the photoelectric conversion efficiency of the perovskite solar cell 10.

[0127] Please see Figure 5 The tandem battery 100 of this application embodiment includes the perovskite solar cell 10 described above.

[0128] In the tandem solar cell 100 of this application embodiment, since the oxygen content of the multilayer conductive film of the perovskite solar cell 10 decreases along the direction from the glass substrate 11 to the electrode 16, the performance of the conductive layer 12 can be improved, making the conductive layer 12 more compatible with the other film layers of the perovskite solar cell 10, thereby improving the photoelectric conversion efficiency of the perovskite solar cell 10.

[0129] The tandem solar cell 100 also includes a crystalline silicon cell 20 stacked with the perovskite solar cell 10. Examples include IBC cells, PERC cells, Topcon cells, and HJT cells.

[0130] Specifically, the perovskite solar cell 10 and the crystalline silicon cell 20 can be connected in series; the perovskite solar cell 10 and the crystalline silicon cell 20 can be connected in parallel; some of the perovskite solar cells 10 and the crystalline silicon cells 20 can be connected in series, and some of the perovskite solar cells 10 and the crystalline silicon cells 20 can be connected in parallel.

[0131] Please see Figure 5 The stacked battery 100 is a four-terminal stacked battery. It can be understood that in other examples, the stacked battery 100 may also be a two-terminal stacked battery.

[0132] For further explanations and descriptions regarding this embodiment, please refer to the preceding text. To avoid redundancy, they will not be repeated here.

[0133] In summary, the perovskite solar cells and their fabrication methods, as well as the tandem cells of this application, achieve low resistivity, high transmittance, low carrier concentration, and high electron mobility by depositing multilayer conductive films with decreasing oxygen content in a stepwise manner. Thus, by optimizing the deposition pattern of the conductive films, matching with the other layers of the perovskite solar cell 10 is achieved.

[0134] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A perovskite solar cell, characterized in that, It includes a glass substrate, a conductive layer, a first contact layer, a perovskite light-absorbing layer, a second contact layer, and an electrode, which are stacked sequentially; the conductive layer includes multiple conductive films, and the oxygen content of the multiple conductive films decreases along the direction from the glass substrate to the electrode; The conductive layer comprises a transparent conductive oxide (TCO) and three conductive films, namely a first conductive film, a second conductive film, and a third conductive film, along the direction from the glass substrate to the electrode. The oxygen content of the first, second, and third conductive films decreases in that order. The thickness of the first conductive film ranges from 80 nm to 85 nm; the thickness of the second conductive film ranges from 50 nm to 55 nm; the thickness of the third conductive film ranges from 40 nm to 45 nm; the thickness of the first contact layer ranges from 10 nm to 100 nm; the thickness of the perovskite light-absorbing layer ranges from 400 nm to 450 nm; and the thickness of the second contact layer ranges from 70 nm to 100 nm. The refractive index of the first, second, and third conductive films increases in that order.

2. The perovskite solar cell according to claim 1, characterized in that, The electrode is multilayered, and the oxygen content of the multilayered electrodes decreases sequentially along the direction from the glass substrate to the electrode.

3. A method for fabricating a perovskite solar cell, characterized in that, include: A conductive layer is formed by sequentially depositing multiple conductive films with decreasing oxygen content on a glass substrate. A first contact layer, a perovskite light-absorbing layer, a second contact layer, and an electrode are sequentially deposited on the conductive layer; The conductive layer comprises a transparent conductive oxide (TCO) and three conductive films arranged along the direction from the glass substrate to the electrode: a first conductive film, a second conductive film, and a third conductive film. The oxygen content of the first, second, and third conductive films decreases, while their refractive indices increase. The thickness of the first conductive film ranges from 80 nm to 85 nm; the thickness of the second conductive film ranges from 50 nm to 55 nm; the thickness of the third conductive film ranges from 40 nm to 45 nm; the thickness of the first contact layer ranges from 10 nm to 100 nm; the thickness of the perovskite light-absorbing layer ranges from 400 nm to 450 nm; and the thickness of the second contact layer ranges from 70 nm to 100 nm.

4. The method for fabricating a perovskite solar cell according to claim 3, characterized in that, The conductive layer comprises three conductive films, which are sequentially deposited on a glass substrate with decreasing oxygen content to form the conductive layer, including: A first conductive film is deposited on a glass substrate; A second conductive film is deposited on the first conductive film; A third conductive film is deposited on the second conductive film, wherein the oxygen content of the first conductive film, the second conductive film, and the third conductive film decreases in that order.

5. The method for fabricating a perovskite solar cell according to claim 3, characterized in that, A first contact layer, a perovskite light-absorbing layer, a second contact layer, and an electrode are sequentially deposited on the conductive layer, including: The first contact layer is deposited on the conductive layer; Deposit the perovskite light-absorbing layer on the first contact layer; A second contact layer is deposited on the perovskite light-absorbing layer; The electrode is deposited on the second contact layer.

6. A perovskite solar cell, characterized in that, It is prepared by the method described in any one of claims 3-5.

7. A stacked battery, characterized in that, Including the perovskite solar cell as described in claim 1, 2 or 6.

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