Perovskite solar cell, preparation method thereof and photovoltaic module

Abstract

The invention relates to the field of solar cells, in particular to a perovskite solar cell, a preparation method and a photovoltaic module. The invention discloses a perovskite solar cell. The perovskite solar cell comprises an electron transport layer; the first tin oxide layer is arranged on the electron transport layer, and the oxygen vacancy content of the first tin oxide layer is 1.0 * 1019 / cm < 3 >-1.0 * 1020 / cm < 3 >; the second tin oxide layer is arranged on the surface, away from the electron transport layer, of the first tin oxide layer, and the oxygen vacancy content of the second tin oxide layer is 1.0 * 1017 / cm < 3 >-1.0 * 1018 / cm < 3 >; and the transparent conductive layer is arranged on the surface, deviating from the first tin oxide layer, of the second tin oxide layer. The oxygen vacancy content of the first tin oxide layer in the perovskite solar cell is larger than that of the second tin oxide layer, and the energy level of the first tin oxide layer moves upwards compared with that of the second tin oxide layer, so that the energy level matching effect of the electron transmission layer and the transparent conductive layer is better, and the photoelectric performance of the perovskite solar cell is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solar cells, in particular to a perovskite solar cell, a preparation method thereof and a photovoltaic module. BACKGROUND

[0002] The electron transport layer and the transparent conductive layer in the perovskite solar cell have the problem of large potential barrier. When a buffer layer is arranged between the two film layers to adjust the energy level, the conductive performance of the film layer is easily affected, and the improvement degree of the energy level is limited, which affects the improvement effect of the photoelectric performance of the perovskite solar cell. SUMMARY

[0003] The present application discloses a perovskite solar cell, a preparation method thereof and a photovoltaic module, which can better balance the conductive performance and energy level matching of the film layer, thereby effectively improving the photoelectric performance of the perovskite solar cell.

[0004] In order to achieve the above-mentioned purpose, in a first aspect, the present application discloses a perovskite solar cell, comprising: an electron transport layer; a first tin oxide layer, the first tin oxide layer being arranged on the electron transport layer, the oxygen vacancy content of the first tin oxide layer being 1.0 x 10 19 / cm 3 ~1.0 x 10 20 / cm 3 ; a second tin oxide layer, the second tin oxide layer being arranged on the surface of the first tin oxide layer away from the electron transport layer, the oxygen vacancy content of the second tin oxide layer being 1.0 x 10 17 / cm 3 ~1.0 x 10 18 / cm 3 ; a transparent conductive layer, the transparent conductive layer being arranged on the surface of the second tin oxide layer away from the first tin oxide layer.

[0005] Further, the carrier concentration of the first tin oxide layer is 1.0 x 10 19 / cm 3 ~1.0 x 10 20 / cm 3 ; and / or, the water contact angle of the first tin oxide layer is 112°~122°; and / or, the hydroxyl coverage of the first tin oxide layer is less than or equal to 6%. Further, the hydroxyl coverage in the second tin oxide layer is 20%~25%; and / or, the water contact angle of the second tin oxide layer is 76°-90°; and / or, the carrier concentration of the second tin oxide layer is 5.0×10 17 / cm 3 -5.0×10 18 / cm 3 .

[0006] Further, the thickness of the first tin oxide layer is 2 nm-12 nm, the thickness of the second tin oxide layer is 8 nm-17 nm, and the thickness of the second tin oxide layer is 2.4-2.6 times the thickness of the first tin oxide layer.

[0007] Further, the perovskite solar cell is a perovskite tandem cell, which comprises a bottom cell, and an electron-hole recombination layer, a hole transport layer, a perovskite layer, the electron transport layer, the first tin oxide layer, the second tin oxide layer, the transparent conductive layer and a first electrode which are sequentially stacked on the surface of the bottom cell; one of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode. The perovskite solar cell is a perovskite single-junction solar cell, which comprises a glass substrate, and a transparent conductive substrate, a hole transport layer, a perovskite layer, the electron transport layer, the first tin oxide layer, the second tin oxide layer, the transparent conductive layer and a first electrode which are sequentially stacked on the surface of the glass substrate; the perovskite single-junction solar cell further comprises a second electrode, the second electrode and the hole transport layer are arranged on different regions of the same side surface of the transparent conductive substrate, and one of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode.

[0008] Further, the perovskite solar cell is the tandem cell; The bottom cell is any one of a heterojunction cell, a passivated contact cell, a copper-indium-gallium-selenium cell, and an organic cell; The electron-hole recombination layer is one or more of indium tin oxide, indium zinc oxide or indium tungsten oxide, and the thickness of the electron-hole recombination layer is 20 nm-30 nm; The hole transport layer is one or more of a nickel oxide layer or a SAM layer, and the thickness of the hole transport layer is 20 nm-30 nm; The thickness of the perovskite layer is 450 nm-500 nm, and the material of the perovskite layer has a general chemical formula ABX3, wherein A is an A-site cation, B is a B-site cation, and X is an X-site anion; the A-site cation includes FA + , MA + , Cs+ , K + , Ca 2+ , Zn 2+ , Na + , Rb + , DMA + , BA + , PA + , AA + , BMIM + , EA + , or EDA 2+ ; and / or, the B-site cation comprises at least one of Pb 2+ , Ga 2+ , and Sn 2+ ; and / or, the X-site anion comprises at least one of I - , F - , Br - , Cl - , SCN - , OCN - , BF4 - , TFSI - , CF3 - , CF3CO2 - , COO - , or SO3 - ; The thickness of the electron transport layer is 15 nm to 20 nm. The thickness of the transparent conductive layer is 25 nm to 100 nm.

[0009] In a second aspect, the present application provides a preparation method of a perovskite solar cell, the perovskite solar cell being the perovskite solar cell of the first aspect, the preparation method comprising the following steps: Preparation of a first tin oxide layer on the electron transport layer, the first tin oxide layer having an oxygen vacancy content of 1.0 x 10 19 / cm 3 ~1.0 x 10 20 / cm 3 ; Preparation of a second tin oxide layer on the first tin oxide layer, the second tin oxide layer having an oxygen vacancy content of 1.0 x 10 17 / cm 3 ~1.0 x 10 18 / cm 3 ; Preparation of a transparent conductive layer on the second tin oxide layer.

[0010] Further, the step of preparing the first tin oxide layer comprises: introducing a tin source and a water source on the electron transport layer, the heating temperature of the tin source is 60-90℃, the flow rate of the non-reactive gas carrying the tin source and the water source is 45-70sccm, the source-on time of the tin source is 0.1-2s, the purge time is 0.2-2s, the source-on time of the water source is 0-0.1s, the purge time is 2-5s, and the cycle is 30 times, to obtain the first tin oxide layer; and / or, The step of preparing the second tin oxide layer comprises: introducing the tin source and the water source on the first tin oxide layer, the heating temperature of the tin source is 60-90℃, the flow rate of the non-reactive gas carrying the tin source and the water source is 45-70sccm, the source-on time of the tin source is 0.1-0.5s, the purge time is 0.6-8s, the source-on time of the water source is 0.015s, and the purge time is 0-0.03s, and the cycle is 40-120 times, to obtain the second tin oxide layer.

[0011] Further, the tin source is tetrakis(dimethylamino)tin or tetrakis(ethylmethylamide)tin; and / or, The water source comprises any one of water, water and ozone, water and oxygen plasma, etc.; and / or, Before preparing the first tin oxide layer, the preparation method further comprises preheating, and the preheating conditions comprise: heating at 60-90℃ for 10-20min.

[0012] Further, the carrier concentration of the first tin oxide layer is 1.0×10 19 / cm 3 ~1.0×10 20 / cm 3 ; and / or, The water contact angle of the first tin oxide layer is 112-122°; and / or, The hydroxyl coverage of the first tin oxide layer is less than or equal to 6%; and / or, The hydroxyl coverage of the second tin oxide layer is 20-25%; and / or, The carrier concentration of the second tin oxide layer is 5.0×10 17 / cm 3 ~5.0×10 18 / cm 3 ; and / or, The water contact angle of the second tin oxide layer is 76-90°.

[0013] In a third aspect, the present application provides a photovoltaic module, which comprises the perovskite solar cell according to the first aspect, or which comprises the perovskite solar cell prepared by the preparation method according to the second aspect.

[0014] Compared with the prior art, the present application has the following beneficial effects: In the perovskite solar cell provided in the embodiments of the present application, in the direction from the electron transport layer to the transparent conductive layer, the first tin oxide layer and the second tin oxide layer with the oxygen vacancy content decreasing in turn are arranged, so that the conductive performance and the energy level matching of the film layer can be better balanced, thereby effectively improving the photoelectric performance of the perovskite solar cell.

[0015] The content of the oxygen vacancies of the first tin oxide layer is 1.0*10 19 / cm 3 ~1.0*10 20 / cm 3 The content of the oxygen vacancies of the second tin oxide layer is 1.0*10 17 / cm 3 ~1.0*10 18 / cm 3 The content of the oxygen vacancies of the first tin oxide layer is greater than the content of the oxygen vacancies of the second tin oxide layer, so that the carrier concentration in the first tin oxide layer is increased compared with the second tin oxide layer. The increase of the carrier concentration can compensate for the influence of the increase of the oxygen vacancies on the electron transport and extraction, thereby reducing or even offsetting the adverse effect of too many oxygen vacancies on the conductive performance, and ensuring the overall conductive performance of the film layer between the electron transport layer and the transparent conductive layer. On the basis of ensuring the conductive performance, the content of the oxygen vacancies of the first tin oxide layer is greater than the content of the oxygen vacancies of the second tin oxide layer, so that the energy level of the first tin oxide layer is shifted upward compared with the second tin oxide layer, and the energy level matching effect between the electron transport layer and the transparent conductive layer is better. Since the two tin oxide layers with the specified oxygen vacancy content are additionally arranged, the conductive performance is not obviously affected, and the energy level matching degree between the electron transport layer and the transparent conductive layer can be effectively improved, so that the photoelectric performance of the perovskite solar cell can be more effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0017] Figure 1 is a structural schematic diagram of a first perovskite solar cell provided in the embodiments of the present application; Figure 2is a structural schematic diagram of a second perovskite solar cell provided by an embodiment of the present application; Figure 3 is a structural schematic diagram of a third perovskite solar cell provided by an embodiment of the present application; Figure 4 is an XPS test spectrum diagram of a second tin oxide layer in Embodiment 1 of the present application; Figure 5 is an XPS test spectrum diagram of a first tin oxide layer in Comparative Example 1 of the present application.

[0018] Legend of reference signs: 1, electron transport layer; 21, first tin oxide layer; 22, second tin oxide layer; 3, transparent conductive layer; 31, anti-reflection layer; 4, bottom cell; 41, electron-hole recombination layer; 5, hole transport layer; 51, modification layer; 6, perovskite layer; 61, passivation layer; 71, first electrode; 72, second electrode; 8, glass substrate; 9, transparent conductive substrate. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0020] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0021] In addition, in addition to indicating the orientation or positional relationship, the above-mentioned part of the terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. Those of ordinary skill in the art can understand the specific meaning of these terms in the present application according to the specific situation.

[0022] In addition, the terms "mount", "set", "provided with", "connect", "connected" should be broadly understood. For example, it can be fixed connection, detachable connection, or integral structure; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or internal communication between two devices, elements or components. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0023] In addition, the terms "first", "second" and the like are mainly used to distinguish different devices, elements or components (the specific type and structure may be the same or different), and are not intended to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise stated, the meaning of "multiple" is two or more.

[0024] In perovskite solar cells, the barrier between the electron transport layer and the transparent conductive layer is large, and there is a problem of energy level mismatch. Although a buffer layer can be provided between the two layers, the energy level mismatch can be slightly improved, but the improvement is limited; in addition, some materials suitable as a buffer layer generally have poor conductivity, which is not conducive to efficient transmission of charge carriers after being added. Therefore, after adding a buffer layer, the photoelectric performance of the perovskite solar cell has not been effectively improved. It is necessary to make further improvements.

[0025] Based on the above analysis, the embodiments of the present application provide a perovskite solar cell and a preparation method thereof, and a photovoltaic module. By reducing or even eliminating the adverse effects of adding a buffer layer on the conductivity, and further increasing the energy level matching, the photoelectric performance of the perovskite solar cell is effectively improved.

[0026] As shown in Figures 1-3 The embodiments of the present application provide a perovskite solar cell, which comprises: an electron transport layer 1; a first tin oxide layer 21, the first tin oxide layer 21 being disposed on the electron transport layer 1, the oxygen vacancy content of the first tin oxide layer 21 being 1.0x10 19 / cm 3 ~1.0x10 20 / cm 3 ; a second tin oxide layer 22, the second tin oxide layer 22 being disposed on the surface of the first tin oxide layer 21 away from the electron transport layer 1, the oxygen vacancy content of the second tin oxide layer 22 being 1.0x10 17 / cm 3 ~1.0x10 18 / cm 3 ; A transparent conductive layer 3 is provided on the surface of the second tin oxide layer 22 facing away from the first tin oxide layer 21.

[0027] The oxygen vacancy content is measured by a Hall effect tester. Oxygen vacancy is a donor defect, and each oxygen vacancy contributes 1-2 free electrons. Therefore, the concentration of ionized oxygen vacancies can be obtained by measuring the free electron concentration in the thin film by a Hall effect tester. In an ideal tin oxide (SnO2) lattice, tin exists in the form of Sn 4+ , and oxygen exists in the form of O 2- , and the charge is balanced. However, in an actual tin oxide (SnO x ) layer, O 2- may be separated from the lattice, that is, there are oxygen vacancies in the tin oxide layer. In the embodiments of the present application, the oxygen vacancy content of the first tin oxide layer 21 is 1.0×10 19 / cm 3 ~1.0×10 20 / cm 3 , including any point value in the range, for example, the oxygen vacancy content of the first tin oxide layer 21 is 1.0×10 19 / cm 3 , 4.0×10 19 / cm 3 , 7.0×10 19 / cm 3 , 9.0×10 19 / cm 3 , or 1.0×10 20 / cm 3 . The oxygen vacancy content of the second tin oxide layer 22 is 1.0×10 17 / cm 3 ~1.0×10 18 / cm 3 , including any point value in the range, for example, the oxygen vacancy content of the second tin oxide layer 22 is 1.0×10 17 / cm 3 , 3.0×10 17 / cm 3 , 5.0×10 17 / cm 3 , 7.0×10 17 / cm 3 , or 1.0×10 18 / cm 3 .

[0028] In the perovskite solar cell provided in the embodiments of the present application, the oxygen vacancy content of the first tin oxide layer 21 close to the electron transport layer 1 is controlled to be 1.0×10 19 / cm 3 ~1.0×1020 / cm 3 The oxygen vacancy content of the second tin oxide layer 22 close to the transparent conductive layer 3 is controlled to be 1.0 x 10 17 / cm 3 ~1.0 x 10 18 / cm 3 The first tin oxide layer 21 close to the electron transport layer 1 is made into a high oxygen vacancy content layer (relative to the second tin oxide layer 22), and the second tin oxide layer 22 close to the transparent conductive layer 3 is made into a low oxygen vacancy content layer.

[0029] At the same time, since the oxygen vacancy of the first tin oxide layer 21 is more than that of the second tin oxide layer 22, the energy level of the first tin oxide layer 21 is shifted upward compared to that of the second tin oxide layer 22, which makes the energy level between the electron transport layer 1 and the transparent conductive layer 3 have a better transition level than that of only one tin oxide layer. At the same time, since the oxygen vacancy of the first tin oxide layer 21 and the second tin oxide layer 22 is controlled within the above range, and the first tin oxide layer 21 is close to the electron transport layer 1 and the second tin oxide layer 22 is close to the transparent conductive layer 3, the energy level between the electron transport layer 1 and the transparent conductive layer 3 is more highly matched.

[0030] At the same time, since the first tin oxide layer 21 is a film layer with relatively more oxygen vacancies, in order to maintain local charge balance, Sn 4+ around the oxygen vacancies will capture electrons to reduce the valence state (for example, to Sn 3+ or Sn 2+ ), and the excess electrons will escape from the Sn ion to become free electrons (i.e. carriers). This makes the first tin oxide layer 21 a film layer with a relatively higher carrier concentration, so that the conductive performance of the first tin oxide layer 21 can be enhanced by a higher carrier concentration, thereby compensating for the problem of increased recombination defects caused by oxygen vacancies, and thus the first tin oxide layer 21 also maintains good conductive performance in the case of high oxygen vacancies.

[0031] As can be seen, through the specific oxygen vacancy content control of the first tin oxide layer 21 and the second tin oxide layer 22 described above, the conductive performance and energy level matching between the electron transport layer 1 and the transparent conductive layer 3 can be better balanced, ensuring that the conductive performance is not significantly impaired, and at the same time, the energy level between the electron transport layer 1 and the transparent conductive layer 3 has a higher matching degree, thereby effectively improving the photoelectric conversion efficiency of the perovskite solar cell.

[0032] Further, the carrier concentration of the first tin oxide layer 21 is 1.0 x 10 19 / cm 3 ~1.0 x 10 20 / cm 3 .

[0033] wherein the carrier concentration is tested by a Hall effect tester.

[0034] Exemplarily, the carrier concentration of the first tin oxide layer 21 is 1.0 x 10 19 / cm 3 , 2.0 x 10 19 / cm 3 , 4.0 x 10 19 / cm 3 , 6.0 x 10 19 / cm 3 , 7.0 x 10 19 / cm 3 , 9.0 x 10 19 / cm 3 or 1.0 x 10 20 / cm 3 . Preferably, the carrier concentration of the first tin oxide layer 21 is 9.0 x 10 19 / cm 3 .

[0035] In the embodiments of the present application, the carrier concentration of the first tin oxide layer 21 is 1.0 x 10 19 / cm 3 ~ 1.0 x 10 20 / cm 3 , which is one order of magnitude higher than that of the ideal lattice structure of tin dioxide, and thus the carrier concentration has a major impact on the conductivity of the film layer. The increase in the carrier concentration makes the number of movable charge carriers in the unit volume of the first tin oxide layer 21 larger, and since the variation degree of the elementary charge and the carrier mobility is smaller than the carrier concentration, the conductivity of the film layer is increased, the current density of the film layer is increased when the same electric field is applied, the conductive performance of the first tin oxide layer 21 is improved, and further, the overall conductive performance of the film layer between the electron transport layer 1 and the transparent conductive layer 3 is improved.

[0036] Further, the water contact angle of the first tin oxide layer 21 is 112° ~ 122°.

[0037] wherein the water contact angle is calculated by injecting a 1 μL ~ 5 μL droplet of ultrapure water above the surface of the sample, collecting relevant image information, and using a digital model to calculate the contact angle value, and measuring at least 5 points on different positions of the sample surface and taking the average value.

[0038] Exemplarily, the water contact angle of the first tin oxide layer 21 is 112°, 114°, 115°, 116°, 119°, 120° or 122°. Preferably, the water contact angle of the first tin oxide layer 21 is 119°.

[0039] In the embodiments of the present application, the water contact angle of the first tin oxide layer 21 indicates that the first tin oxide layer 21 has hydrophobicity, can serve as a strong barrier for water molecule penetration, reduces the hydrolysis of the film layer below the first tin oxide layer 21 in the perovskite solar cell, and improves the stability of the perovskite solar cell.

[0040] Further, the hydroxyl coverage of the first tin oxide layer 21 is less than or equal to 6%.

[0041] The hydroxyl coverage is obtained by XPS test analysis by an X-ray photoelectron spectrometer.

[0042] For example, the hydroxyl coverage of the first tin oxide layer 21 is 1%, 2%, 4%, 5% or 6%.

[0043] In the embodiments of the present application, the hydroxyl coverage of the first tin oxide layer 21 indicates that the first tin oxide layer 21 has hydrophobicity, thereby improving the stability of the perovskite solar cell.

[0044] Further, the hydroxyl coverage of the second tin oxide layer 22 is 20% to 25%.

[0045] For example, the hydroxyl coverage of the second tin oxide layer 22 is 20%, 21%, 22%, 23%, 24% or 25%.

[0046] In the embodiments of the present application, the strong polarity of the hydroxyl gives the surface hydrophilicity. When the hydroxyl coverage is 20% to 25%, the work function of the second tin oxide layer 22 is improved, the energy level of the second tin oxide layer 22 is reduced, and the barrier of the film layer and the transparent conductive layer 3 is reduced. The difference in oxygen vacancy content between the first tin oxide layer 21 and the second tin oxide layer 22 causes the energy level gradient between the two film layers. The second tin oxide layer 22 has a hydroxyl coverage of 20% to 25%, so that the energy level of the film layer is further reduced, the energy level gradient between the second tin oxide layer 22 and the transparent conductive layer 3 changes more gently, and the energy level matching effect between the electron transport layer 1 and the transparent conductive layer 3 is better. At the same time, the hydroxyl coverage enables the second tin oxide layer 22 to better match the surface energy of the transparent conductive layer 3, improves the contact performance of the second tin oxide layer 22 and the transparent conductive layer 3, reduces the contact resistance, and promotes the electron transport between the two film layers.

[0047] Further, the water contact angle of the second tin oxide layer 22 is 76° to 90°.

[0048] For example, the water contact angle of the second tin oxide layer 22 is 76°, 79°, 81°, 85°, 88° or 90°.

[0049] In the embodiments of the present application, the water contact angle of the second tin oxide layer 22 indicates that the second tin oxide layer 22 has hydrophilicity.

[0050] Further, the carrier concentration of the second tin oxide layer 22 is 5.0 x 10 17 / cm 3 ~5.0 x 10 18 / cm 3 .

[0051] Illustratively, the carrier concentration of the second tin oxide layer 22 is 5.0 x 10 17 / cm 3 , 6.0 x 10 17 / cm 3 , 7.0 x 10 17 / cm 3 , 9.0 x 10 17 / cm 3 , 2.0 x 10 18 / cm 3 , 3.0 x 10 18 / cm 3 or 5.0 x 10 18 / cm 3 .

[0052] Further, the thickness of the first tin oxide layer 21 is 2 nm~12 nm, the thickness of the second tin oxide layer 22 is 8 nm~17 nm, and the thickness of the second tin oxide layer 22 is 2.4 times~2.6 times the thickness of the first tin oxide layer 21.

[0053] Illustratively, the thickness of the first tin oxide layer 21 is 2 nm, 4 nm, 5 nm, 7 nm, 9 nm, 10 nm or 12 nm. Preferably, the thickness of the first tin oxide layer 21 is 4.5 nm.

[0054] Illustratively, the thickness of the second tin oxide layer 22 is 8 nm, 11 nm, 14 nm, 16 nm or 12 nm. Preferably, the thickness of the second tin oxide layer 22 is 11.5 nm.

[0055] In the embodiments of the present application, the thickness of the second tin oxide layer 22 is 2.4 times~2.6 times the thickness of the first tin oxide layer 21, the first tin oxide layer 21 is thin to improve conductivity while achieving uniform coverage, and does not reduce light transmission to affect the light absorption of the battery; the second tin oxide layer 22 has a higher hydroxyl coverage rate, residual H + prevents dehydration reaction, improves work function and matches the conduction band of the transparent conductive layer 3, and the combined effect of the first tin oxide layer 21 and the second tin oxide layer 22 is more conducive to electron transport.

[0056] Further, the material of the electron transport layer 1 is one or both of C60 or PCBM; and the material of the transparent conductive layer 3 is one or more of indium tin oxide, indium zinc oxide or indium tungsten oxide.

[0057] wherein PCBM is a derivative of C60.

[0058] In the embodiments of the present application, the energy level of C60 and PCBM is higher than that of the tin oxide material with an oxygen vacancy content of X1, the energy level of the tin oxide material with an oxygen vacancy content of X1 is higher than that of the tin oxide material with an oxygen vacancy content of X2, the energy level of the tin oxide material with an oxygen vacancy content of X2 is higher than that of indium tin oxide, indium zinc oxide or indium tungsten oxide, and therefore the first tin oxide layer 21 and the second tin oxide layer 22 better match the energy level between the electron transport layer 1 and the transparent conductive layer 3, so that the photoelectric performance of the perovskite solar cell is improved.

[0059] As an implementable manner, as shown in Figure 1 The perovskite solar cell is a perovskite stacked cell, and the perovskite stacked cell comprises a bottom cell 4, and an electron-hole recombination layer 41, a hole transport layer 5, a perovskite layer 6, an electron transport layer 1, a first tin oxide layer 21, a second tin oxide layer 22, a transparent conductive layer 3 and a first electrode 71 which are sequentially stacked on the surface of the bottom cell 4; the side of the bottom cell 4 away from the perovskite layer 6 is provided with a second electrode 72, and one of the first electrode 71 and the second electrode 72 is a positive electrode and the other is a negative electrode.

[0060] The bottom cell 4 comprises any one of a heterojunction cell, a passivated contact cell, a copper indium gallium selenide cell and an organic cell.

[0061] The material of the electron-hole recombination layer 41 is one or more of indium tin oxide, indium zinc oxide or indium tungsten oxide, and the thickness of the electron-hole recombination layer 41 is 20 nm to 30 nm.

[0062] Exemplarily, the thickness of the electron-hole recombination layer 41 is 20 nm, 22 nm, 23 nm, 25 nm, 27 nm, 29 nm or 30 nm. Preferably, the thickness of the electron-hole recombination layer 41 is 20 nm.

[0063] The hole transport layer 5 is one or more of a nickel oxide layer and a SAM layer, and the thickness of the hole transport layer 5 is 20 nm to 30 nm.

[0064] Exemplarily, the thickness of the hole transport layer 5 is 20 nm, 22 nm, 23 nm, 25 nm, 27 nm, 29 nm or 30 nm. Preferably, the thickness of the hole transport layer 5 is 20 nm, 22 nm, 23 nm, 25 nm, 27 nm, 29 nm or 30 nm. The thickness of the hole transport layer 5 is 18 nm.

[0065] The SAM layer is a self-assembled molecular layer, and the material thereof includes one or more of 4PACz, 4PADCB, MeO-2PACz, 2PACz or Me-4PACz, the material of the polymer molecular layer includes one or more of poly-4PACz, poly-4PADCB or PTAA, and the molecular weight of the material of the polymer molecular layer is greater than or equal to 1000. The 4PACz, MeO-2PACz, 4PACz or MeO-2PACz are all derivatives of carbazole phosphonic acid (PACz). The poly-4PACz, poly-4PADCB or PTAA are polymers formed by polymerization of carbazole derivatives.

[0066] The material of the perovskite layer 6 has a general chemical formula ABX3, wherein A is an A-site cation, B is a B-site cation, and X is an X-site anion; the A-site cation includes at least one of FA + , MA + , Cs + , K + , Ca 2+ , Zn 2+ , Na + , Rb + , DMA + , BA + , PA + , AA + , BMIM + , EA + or EDA 2+ ; and / or, the B-site cation includes at least one of Pb 2+ , Ga 2+ and Sn 2+ ; and / or, the X-site anion includes at least one of I - , F - , Br - , Cl - , SCN - , OCN - , BF4 - , TFSI - , CF3 - , CF3CO2 - , COO - or SO3 - .

[0067] The thickness of the perovskite layer 6 is 450 nm to 500 nm.

[0068] Exemplarily, the thickness of the perovskite layer 6 is 450 nm, 455 nm, 460 nm, 470 nm, 474 nm, 483 nm, 492 nm or 500 nm. Preferably, the thickness of the perovskite layer 6 is 450 nm.

[0069] The thickness of the electron transport layer 1 is 15 nm to 20 nm.

[0070] Exemplarily, the thickness of the electron transport layer 1 is 15 nm, 16 nm, 17 nm, 18 nm, 19 nm or 20 nm. Preferably, the thickness of the electron transport layer 1 is 16 nm.

[0071] The thickness of the transparent conductive layer 3 is 25 nm to 100 nm.

[0072] Exemplarily, the thickness of the transparent conductive layer 3 is 25 nm, 35 nm, 40 nm, 50 nm, 63 nm, 72 nm, 86 nm, 93 nm or 100 nm. Preferably, the thickness of the transparent conductive layer 3 is 40 nm.

[0073] As an implementable manner, as shown in Figure 2 The perovskite solar cell is a perovskite single-junction solar cell, which comprises a glass substrate 8, and a transparent conductive substrate 9, a hole transport layer 5, a perovskite layer 6, an electron transport layer 1, a first tin oxide layer 21, a second tin oxide layer 22, a transparent conductive layer 3 and a first electrode 71 which are sequentially stacked on the surface of the glass substrate 8; the perovskite single-junction solar cell further comprises a second electrode 72, the second electrode 72 and the hole transport layer 5 are arranged on different regions of the same side surface of the transparent conductive substrate 9, and the first electrode 71 and the second electrode 72 are one anode and the other cathode.

[0074] The material of the transparent conductive substrate 9 is one or more of indium tin oxide, indium zinc oxide or indium tungsten oxide, and the thickness of the transparent conductive substrate 9 is 20 nm to 50 nm.

[0075] Exemplarily, the thickness of the transparent conductive substrate 9 is 20 nm, 28 nm, 37 nm, 42 nm, 47 nm or 50 nm. Preferably, the thickness of the transparent conductive substrate 9 is 37 nm.

[0076] In addition to the above structure, the perovskite solar cell can further comprise other functional film layers, such as Figure 3 As shown in A modification layer 51 is arranged between the hole transport layer 5 and the perovskite layer 6. The modification layer 51 is a self-assembled molecular layer or a polymer molecular layer. The material of the self-assembled molecular layer includes one or more of 4PACz, 4PADCB, MeO-2PACz, 2PACz, or Me-4PACz. The material of the polymer molecular layer includes one or more of poly-4PACz, poly-4PADCB, or PTAA. The molecular weight of the material of the polymer molecular layer is greater than or equal to 1000. The 4PACz, MeO-2PACz, 4PACz, or MeO-2PACz are derivatives of carbazole phosphonic acid (PACz). The poly-4PACz, poly-4PADCB, or PTAA are polymers formed by polymerization of carbazole derivatives.

[0077] A passivation layer 61 is arranged between the perovskite layer 6 and the electron transport layer 1. The material of the passivation layer 61 includes LiF or a two-dimensional perovskite material. The thickness of the passivation layer 61 is 1 nm to 3 nm.

[0078] For example, the thickness of the passivation layer 61 is 1 nm, 2 nm, or 3 nm. Preferably, the thickness of the passivation layer 61 is 1 nm.

[0079] A reduction layer 31 is arranged on the surface of the transparent conductive layer 3. The material of the reduction layer 31 is LiF or MgF2. The thickness of the reduction layer 31 is 100 nm to 120 nm.

[0080] For example, the thickness of the reduction layer 31 is 100 nm, 104 nm, 107 nm, 109 nm, 113 nm, 116 nm, 118 nm, or 120 nm. Preferably, the thickness of the reduction layer 31 is 100 nm.

[0081] In the embodiments of the present application, the modification layer 51, the passivation layer 61, and the reduction layer 31 further improve the photoelectric conversion efficiency of the perovskite solar cell.

[0082] The embodiments of the present application also provide a preparation method of the perovskite solar cell. It can be understood that the preparation method is one method for obtaining the embodiments of the present application, but is not limited to the only method. That is, the perovskite solar cell of the embodiments of the present application can also be prepared by other methods, which is not limited by the present application. Therefore, the preparation method provided by the embodiments of the present application should not be understood as a limitation on the perovskite solar cell.

[0083] The preparation method includes the following steps: A first tin oxide layer 21 is prepared on the electron transport layer 1. The oxygen vacancy content of the first tin oxide layer 21 is 1.0×10 19 / cm 3 ~1.0×1020 / cm 3 ; A second tin oxide layer 22 is prepared on the first tin oxide layer 21, and the oxygen vacancy content of the second tin oxide layer 22 is 1.0*10 17 / cm 3 ~1.0*10 18 / cm 3 ; A transparent conductive layer 3 is prepared on the second tin oxide layer 22.

[0084] Further, the step of preparing the first tin oxide layer 21 comprises: introducing a tin source and a water source on the electron transport layer 1, the heating temperature of the tin source is 60-90℃, the flow rate of the non-reactive gas carrying the tin source and the water source is 45-70 sccm, the source-on time of the tin source is 0.1-2 s, the purge time is 0.2-2 s, the source-on time of the water source is 0-0.1 s, the purge time is 2-5 s, and the cycle is 30 times, to obtain the first tin oxide layer 21.

[0085] The non-reactive gas is nitrogen or argon.

[0086] The tin source is tetrakis(dimethylamino)tin or tert-butyltin, and preferably, the tin source is tetrakis(dimethylamino)tin.

[0087] The water source includes any one of water, water and ozone, and water and oxygen plasma.

[0088] Preferably, the heating temperature of the tin source is 70℃, the flow rate of the non-reactive gas carrying the tin source and the water source is 59 sccm, the source-on time of the tin source is 1.6 s, the purge time is 1.5 s, the source-on time of the water source is 0.015 s, and the purge time is 4.8 s, and the cycle is 30 times.

[0089] Further, before preparing the first tin oxide layer, the preparation method further comprises preheating, and the preheating condition comprises: heating at 60-90℃ for 10-20 min. Preferably, the preheating condition is heating at 80℃ for 15 min. The preheating makes the composition of the first tin oxide layer 21 more uniform.

[0090] In the embodiments of the present application, by controlling the source-on time and the purge time of tetrakis(dimethylamino)tin, the excess tetrakis(dimethylamino)tin not involved in the reaction is not completely removed, the residual hydrophobic group directly increases the contact angle of the first tin oxide layer 21, occupies the active site to inhibit the generation of hydroxyl groups, increases the hydrophobicity, forms a strong barrier for water molecules to penetrate, reduces the hydrolysis of the film layer below the first tin oxide layer 21 in the perovskite solar cell, and improves the stability of the perovskite solar cell.

[0091] Further, the step of preparing the second tin oxide layer 22 comprises: introducing a tin source and a water source on the first tin oxide layer 21, the heating temperature of the tin source is 60-90℃, the flow rate of the non-reactive gas carrying the tin source and the water source is 45-70sccm, the source-on time of the tin source is 0.1-0.5s, the purge time is 0.6-8s, the source-on time of the water source is 0.015s, the purge time is 0-0.03s, and the cycle is 40-120 times, to obtain the second tin oxide layer 22.

[0092] The tin source is tetrakis(dimethylamino)tin or tetrakis(ethylmethylamide)tin, and preferably the tin source is tetrakis(dimethylamino)tin.

[0093] The water source is any one of water, water and ozone, water and oxygen plasma, etc.

[0094] The heating temperature of the tin source is 70℃, the flow rate of the non-reactive gas carrying the tin source and the water source is 59sccm, the source-on time of the tin source is 0.4s, the purge time is 4.8s, the source-on time of the water source is 0.015s, the purge time is 1s, and the cycle is 60 times, to obtain the second tin oxide layer 22.

[0095] In the embodiments of the present application, by controlling the purge time of the deionized water, water molecules as the oxygen source are left, and these physically adsorbed water molecules are dissociated in the subsequent deposition process and form ≡Sn-OH groups with tin, significantly increasing the hydroxyl coverage, and the residual H + The dehydration reaction is prevented, the work function is improved and matched with the IZO conduction band, and the compactness of the film layer is also improved, thereby improving the stability of the perovskite solar cell. In addition, the strong polarity of the hydroxyl group endows the surface with hydrophilicity, matches the surface energy of the transparent conductive layer 3, improves the contact performance of the second tin oxide layer 22 and the transparent conductive layer 3, reduces the contact resistance, and promotes the electron transmission between the two film layers.

[0096] The embodiments of the present application also provide a photovoltaic module. The photovoltaic module comprises the above-mentioned perovskite solar cell, and also comprises the preparation method of the perovskite solar cell.

[0097] The technical solutions of the present application will be further explained below in combination with more specific embodiments and experimental test results.

[0098] Embodiment 1 Step 1: A patterned electron-hole recombination layer is prepared on the HJT bottom cell by magnetron sputtering, and the material of the electron-hole recombination layer is indium tin oxide with a thickness of 20nm. Step 2: A hole transport layer is prepared on the electron-hole recombination layer, and the material of the hole transport layer is nickel oxide with a thickness of 18nm. Step 3: A modification layer is prepared on the hole transport layer, the modification layer material is X, the concentration is 0.8 mg / mL-1 mg / mL, the modification layer is a monolayer, a spin coating process is used for preparation, the rotation speed is 3000 rpm-5000 rpm, the annealing temperature is 80℃-120℃, and the annealing time is 10 min-15 min; Step 4: A skeleton layer is vacuum deposited on the modification layer, the skeleton layer thickness is 450 nm, a double-source co-evaporation process is used for evaporating PbI2 and CsBr, and the evaporation rate ratio is 6:1; Step 5: A cation solution is spin-coated on the skeleton layer by using a spin coating process, the cation solution is a mixed solution of FAI, MABr and MACl, wherein the solvent is anhydrous ethanol; the FAI concentration is 0.3 M-0.6 M, the MABr concentration is 0.1 M-0.2 M, and the MACl concentration is 0.05 M-0.15 M; the spin-coating rotation speed is 3000 rpm-6000 rpm, the spin-coating time is 30 s, the spin-coating environment requires that the humidity is less than 10% and the temperature is 25℃; after the spin-coating is completed, annealing is performed under the condition that the humidity is 5%-40%, the annealing temperature is 100℃-150℃, and the annealing time is 15 min-30 min; after the annealing, a perovskite layer is formed, and the perovskite layer thickness is 450 nm-500 nm; Step 6: A passivation layer is prepared on the perovskite light-absorbing layer by using a vacuum deposition process; the passivation layer material is LiF, the thickness is 1 nm, and the evaporation rate is 0.1 Å / s; Step 7: An electron transport layer is evaporated on the passivation layer; the electron transport layer material is C60, the thickness is X nm, and the evaporation rate is 0.2 Å / s-0.3 Å / s; Step 8: A first tin oxide layer is prepared on the electron transport layer by atomic deposition, the tin source is tetrakis(dimethylamino) tin, and the water source is deionized water; the atomic deposition chamber temperature is 80℃, the process is started after preheating in the chamber for 15 min, the tin source heating temperature is 70℃, the N2 carrying source flow is 59 sccm, the tin source source-on time is 1.6 s, the purge time is 1.5 s, the water source source-on time is 0.015 s, the purge time is 4.8 s, the cycle is 30 times, and the first tin oxide layer thickness is 4.5 nm; Step 9: A second tin oxide layer is prepared on the first tin oxide layer by atomic deposition, the tin source is tetrakis(dimethylamino) tin, and the water source is deionized water; the tin source source-on time is 0.4 s, the purge time is 4.8 s, the water source source-on time is 0.015 s, the purge time is 1 s, the cycle is 60 times, the remaining process conditions are consistent with those of Step 8, and the second tin oxide layer thickness is 11.5 nm; Step 10: A transparent conductive layer is prepared on the second buffer layer by using a magnetron sputtering, the transparent conductive layer material is indium zinc oxide, and the transparent conductive layer thickness is 40 nm. Step 11: Evaporating a first electrode and a second electrode on the transparent conductive layer and the back surface of the HJT bottom cell respectively; the material of the first electrode and the second electrode is silver, and the thickness is 350 nm; Step 12: Preparing an anti-reflection layer on the first electrode, and the material of the anti-reflection layer is LiF, and the thickness is 100 nm.

[0099] Example 2 The difference between this example and Example 1 is that the thickness of the first tin oxide layer is 1 nm.

[0100] Example 3 The difference between this example and Example 1 is that the thickness of the first tin oxide layer is 15 nm.

[0101] Example 4 The difference between this example and Example 1 is that the thickness of the second tin oxide layer is 6 nm.

[0102] Example 5 The difference between this example and Example 1 is that the thickness of the second tin oxide layer is 20 nm.

[0103] Example 6 The difference between this example and Example 1 is that when the second tin oxide layer is prepared, the source time of the tin source is 0.015 s, and the purge time is 4.8 s.

[0104] Comparative Example 1 The difference between this comparative example and Example 1 is that the thickness of the first tin oxide layer is 16 nm, and the second tin oxide layer is not set.

[0105] Comparative Example 2 The difference between this comparative example and Example 1 is that the source time of the tin source is 0.4 s, the purge time is 4.8 s, the thickness of the second tin oxide layer is 16 nm, and the first tin oxide layer is not set.

[0106] Comparative Example 3 The difference between this comparative example and Example 1 is that in Step 8, the source time of the tin source is 0.05 s, and the purge time is 1.5 s.

[0107] Performance Test 1. Oxygen vacancy content, carrier concentration and carrier mobility The corresponding oxygen vacancy content, carrier concentration and carrier mobility of the first tin oxide layer and the second tin oxide layer of Example 1, the tin oxide layer of Comparative Example 1, the second tin oxide layer of Comparative Example 2, and the inner tin oxide layer and the outer tin oxide layer of Comparative Example 3 were tested by a Hall effect tester. The results of three tests are shown in Table 1.

[0108] 2. Water contact angle and hydroxyl coverage A 1-5 μL droplet of ultrapure water was injected on the surface of the first and second tin oxide layers of Example 1, the first tin oxide layer of Comparative Example 1, the second tin oxide layer of Comparative Example 2, and the inner and outer tin oxide layers of Comparative Example 3, respectively, and relevant image information was collected. The contact angle values were calculated using a digital model. The results of the average of 5 points are shown in Table 1.

[0109] 3. Hydroxyl coverage XPS tests were performed on the film layer close to the transparent conductive layer of Example 1 and Comparative Example 1, i.e., the test film layer of Example 1 was the second tin oxide layer, and the test film layer of Comparative Example 1 was the first tin oxide layer, using an X-ray photoelectron spectrometer. The test results of Example 1 are shown in FIG. 2, and the test results of Comparative Example 1 are shown in FIG. 3. The binding energy of lattice oxygen is lower, and the binding energy in the range of 530.3 eV-530.8 eV represents oxygen in the Sn-O bond; the binding energy of surface hydroxyl is higher, and the binding energy in the range of 531.5 eV-532.5 eV represents surface groups such as Sn-OH or adsorbed water. Figure 4 Figure 5 The binding energy of lattice oxygen is lower, and the binding energy in the range of 530.3 eV-530.8 eV represents oxygen in the Sn-O bond; the binding energy of surface hydroxyl is higher, and the binding energy in the range of 531.5 eV-532.5 eV represents surface groups such as Sn-OH or adsorbed water. Figure 4 Figure 5 It can be seen from FIG. 2 and FIG. 3 that the oxygen vacancy content of Example 1 close to the transparent conductive layer is slightly lower than that of Comparative Example 1 close to the transparent conductive layer; the hydroxyl coverage of Example 1 on the side close to the transparent conductive layer is higher, and the hydroxyl coverage of the second tin oxide layer of Example 1 is 23% and the hydroxyl coverage of the first tin oxide layer of Comparative Example 1 is 6% after the peak fitting is calculated to obtain the proportion of the area of each peak to the total area. The remaining hydroxyl coverage in Table 1 is obtained by the same method.

[0110] 3. Photoelectric performance test The open-circuit voltage, fill factor, photoelectric conversion efficiency, and other performance of the perovskite tandem cells of Examples 1-6 and Comparative Examples 1-3 were tested using a halm test sorting device. The halm machine is a device for simulating sunlight, and is equipped with an electronic load, data acquisition and calculation devices, etc., for testing the electrical performance of photovoltaic devices (including solar cells). The calibrated light intensity of the solar cell for testing was controlled to be 1000±5 W / m².

[0111] The test results of items 1-3 of the performance test are shown in Table 1, and the test results of item 3 of the performance test are shown in Table 2.

[0112] Table 1 Performance test results of Example 1 and Comparative Examples 1-3 (I)

[0113] ​​Table 2 Performance test results of Example 1~Example 6 and Comparative Example 1~Comparative Example 3 (two)

[0114] From the data of Table 1 and Table 2, it can be seen that the photoelectric performance of Example 1 is better than that of Comparative Example 1~Comparative Example 3. Compared with Comparative Example 1, Example 1 has a second tin oxide layer with high hydroxyl coverage in addition to the first tin oxide layer with high oxygen vacancy content, which makes the energy level gradient change more gently between the second tin oxide layer and the transparent conductive layer, and has a better energy level matching effect between the electron transport layer and the transparent conductive layer, and thus has better photoelectric performance. Compared with Comparative Example 2, Example 1 has a first tin oxide layer with higher oxygen vacancy content in addition to the second tin oxide layer with high hydroxyl coverage, so it has higher electron transport effect and higher photoelectric efficiency. Example 1 and Comparative Example 3 both have a double-layer tin oxide structure, but the first tin oxide layer of Example 1 has higher oxygen vacancy content, and thus has higher carrier concentration and better electron transport effect, so it has more excellent photoelectric performance.

[0115] From the data of Table 2, it can be seen that the photoelectric conversion efficiency of Example 1 is better than that of Example 2~Example 5, so when the thickness of the second tin oxide layer is 2.4 to 2.6 times the thickness of the first tin oxide layer, the first tin oxide layer is thinner to improve the conductivity while achieving uniform coverage, and does not reduce the light transmittance to affect the light absorption of the cell. By comparing Example 1 and Example 6, it can be seen that when the hydroxyl coverage of the second tin oxide layer is higher, the residual H + prevents the dehydration reaction, improves the work function and matches the conduction band of the transparent conductive layer, and the combined effect of the first tin oxide layer and the second tin oxide layer is more conducive to electron transport, which ultimately improves the photoelectric conversion efficiency of the solar cell.

[0116] The above has introduced the technical solutions disclosed by the embodiments of the present application in detail, and the principles and implementation manners of the present application have been described by applying specific examples. The above description of the embodiments is only for helping to understand the technical solutions and core invention points of the embodiments of the present application. Meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed, and the content of the specification should not be understood as limiting the present application.

Claims

1. A perovskite solar cell, characterized in that, The perovskite solar cell includes: Electron transport layer; A first tin oxide layer is disposed on the electron transport layer, and the oxygen vacancy content of the first tin oxide layer is 1.0 × 10⁻⁶. 19 / cm 3 ~1.0×10 20 / cm 3 ; A second tin oxide layer is disposed on the surface of the first tin oxide layer facing away from the electron transport layer, and the oxygen vacancy content of the second tin oxide layer is 1.0 × 10⁻⁶. 17 / cm 3 ~1.0×10 18 / cm 3 ; A transparent conductive layer is disposed on the surface of the second tin oxide layer opposite to the first tin oxide layer.

2. The perovskite solar cell according to claim 1, characterized in that, The carrier concentration of the first tin oxide layer is 1.0 × 10⁻⁶. 19 / cm 3 ~1.0×10 20 / cm 3 ; and / or, The water contact angle of the first tin oxide layer is 112°~122°; and / or, The hydroxyl coverage of the first tin oxide layer is less than or equal to 6%.

3. The perovskite solar cell according to claim 1, characterized in that, The hydroxyl group coverage in the second tin oxide layer is 20%~25%; and / or, The water contact angle of the second tin oxide layer is 76°~90°; and / or, The carrier concentration of the second tin oxide layer is 5.0 × 10⁻⁶. 17 / cm 3 ~5.0×10 18 / cm 3 .

4. The perovskite solar cell according to claim 1, characterized in that, The thickness of the first tin oxide layer is 2 nm to 12 nm, the thickness of the second tin oxide layer is 8 nm to 17 nm, and the thickness of the second tin oxide layer is 2.4 to 2.6 times the thickness of the first tin oxide layer.

5. The perovskite solar cell according to claim 1, characterized in that, The electron transport layer is made of C60 or PCBM; The transparent conductive layer is made of one or more of indium tin oxide, indium zinc oxide, or indium tungsten oxide.

6. The perovskite solar cell according to any one of claims 1 to 5, characterized in that, The perovskite solar cell is a perovskite tandem cell, comprising: a base cell, and sequentially stacked on the surface of the base cell are an electron-hole recombination layer, a hole transport layer, a perovskite layer, the electron transport layer, a first tin oxide layer, a second tin oxide layer, a transparent conductive layer, and a first electrode; a second electrode is disposed on the side of the base cell opposite to the perovskite layer, and one of the first electrode and the second electrode is a positive electrode and the other is a negative electrode; or, The perovskite solar cell is a perovskite single-junction solar cell, comprising: a glass substrate, and a transparent conductive substrate, a hole transport layer, a perovskite layer, the electron transport layer, a first tin oxide layer, a second tin oxide layer, the transparent conductive layer, and a first electrode, which are sequentially stacked on the surface of the glass substrate; the perovskite single-junction solar cell further comprises a second electrode, which is disposed on different regions of the same side surface of the transparent conductive substrate as the second electrode, and the first electrode is a positive electrode and the second electrode is a negative electrode.

7. The perovskite solar cell according to claim 6, characterized in that, The perovskite solar cell is the stacked cell; The bottom battery is any one of heterojunction battery, passivated contact battery, copper indium gallium selenide battery, and organic battery. The electron-hole recombination layer is one or more of indium tin oxide, indium zinc oxide, or indium tungsten oxide, and the thickness of the electron-hole recombination layer is 20 nm to 30 nm. The hole transport layer is one or more of a nickel oxide layer or a SAM layer, and the thickness of the hole transport layer is 20 nm to 30 nm. The thickness of the perovskite layer is 450 nm to 500 nm, and the material of the perovskite layer has the general chemical formula ABX3, wherein A is an A-site cation, B is a B-site cation, and X is an X-site anion; the A-site cation includes FA. + MA + Cs + K + Ca 2+ Zn 2+ Na + 、Rb + DMA + BA + PA + AA + BMIM + EA + or EDA 2+ At least one of the following; and / or, the B-site cation includes Pb. 2+ Ga 2+ and Sn 2+ At least one of; and / or, the X-position anion includes I - F - ,Br - Cl - SCN - OCN - BF4 - TFSI - CF3 - CF3CO2 - COO - or SO3 - At least one of them; The thickness of the electron transport layer is 15 nm to 20 nm; The thickness of the transparent conductive layer is 25 nm to 100 nm.

8. A method for preparing a perovskite solar cell, characterized in that, The preparation method includes: A first tin oxide layer is fabricated on the electron transport layer, wherein the oxygen vacancy content of the first tin oxide layer is 1.0 × 10⁻⁶. 19 / cm 3 ~1.0×10 20 / cm 3 ; A second tin oxide layer is prepared on the first tin oxide layer, wherein the oxygen vacancy content of the second tin oxide layer is 1.0 × 10⁻⁶. 17 / cm 3 ~1.0×10 18 / cm 3 ; A transparent conductive layer is prepared on the second tin oxide layer.

9. The preparation method according to claim 8, characterized in that, The steps for preparing the first tin oxide layer include: introducing a tin source and a water source into the electron transport layer; the heating temperature of the tin source is 60℃~90℃; the flow rate of the non-reactive gas carrying the tin source and the water source is 45 sccm~70 sccm; the tin source is applied for 0.1 s~2 s and the purging time is 0.2 s~2 s; the water source is applied for 0 s~0.1 s and the purging time is 2 s~5 s; the cycle is repeated 20~40 times to obtain the first tin oxide layer. The steps for preparing the second tin oxide layer include: introducing the tin source and the water source onto the first tin oxide layer, wherein the heating temperature of the tin source is 60℃~90℃, the flow rate of the non-reactive gas carrying the tin source and the water source is 45 sccm~70 sccm, the tin source aeration time is 0.1 s~0.5 s and the purging time is 0.6 s~8 s, the water source aeration time is 0.015 s and the purging time is 0 s~0.03 s, and the cycle is repeated 40 times~120 times to obtain the second tin oxide layer.

10. The preparation method according to claim 9, characterized in that, The tin source is tetra(dimethylamino)tin or tetra(ethylmethylamide)tin; and / or, The water source includes any one of water, water and ozone, or water and oxygen plasma; and / or, Before preparing the first tin oxide layer, the preparation method further includes preheating, wherein the preheating conditions include heating at 60℃~90℃ for 10 min~20 min.

11. The preparation method according to claim 8, characterized in that, The carrier concentration of the first tin oxide layer is 1.0 × 10⁻⁶. 19 / cm 3 ~1.0×10 20 / cm 3 ; and / or, The water contact angle of the first tin oxide layer is 112°~122°; and / or, The hydroxyl coverage of the first tin oxide layer is less than or equal to 6%; and / or, The hydroxyl group coverage in the second tin oxide layer is 20%~25%; and / or, The carrier concentration of the second tin oxide layer is 5.0 × 10⁻⁶. 17 / cm 3 ~5.0×10 18 / cm 3 ; and / or, The water contact angle of the second tin oxide layer is 76°~90°.

12. A photovoltaic module, characterized in that, The photovoltaic module includes the perovskite solar cell as described in any one of claims 1-7 and the preparation method as described in any one of claims 8-11.

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