Solar cell and preparation method therefor, and photovoltaic module

Abstract

Disclosed in the present invention are a solar cell and a preparation method therefor, and a photovoltaic module. The solar cell comprises transparent conductive oxides and first metal electrodes arranged on the transparent conductive oxides, wherein the transparent conductive oxides comprise first transparent conductive sub-oxides and second transparent conductive sub-oxides, which are stacked. By means of the arrangement of the transparent conductive oxides and the first metal electrodes, the short-circuit current and the fill factor of the solar cell are simultaneously improved.

Description

A solar cell and its preparation method, and photovoltaic module

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on January 5, 2024, with application number 202410022537.1 and invention name “A solar cell, its preparation method, and photovoltaic module”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the field of solar cells, and in particular to a solar cell and a preparation method thereof, and a photovoltaic module. Background Art

[0003] In solar cells, the transparent conductive oxide (TCO) layer needs to have excellent light transmittance. At the same time, as a functional film layer in the solar cell, it also contacts the metal electrodes in the solar cell. When the interface contact matching is poor, the contact resistance between the film layers increases, which hinders carrier transfer and affects the photoelectric conversion efficiency of the solar cell.

[0004] Currently, while achieving excellent light transmittance, it is difficult for the transparent conductive layer to simultaneously ensure contact matching with the metal electrode, resulting in difficulty in improving the energy conversion efficiency of solar cells. Summary of the Invention

[0005] In order to improve the energy conversion efficiency of solar cells, embodiments of the present invention disclose a solar cell and a preparation method thereof, and a photovoltaic module.

[0006] In a first aspect, an embodiment of the present invention provides a solar cell.

[0007] The solar cell includes a transparent conductive layer and a first metal electrode arranged on the transparent conductive layer. The thickness of the transparent conductive layer is 85nm to 130nm. The transparent conductive layer includes a first transparent conductive sublayer and a second transparent conductive sublayer arranged in a stacked manner. The ratio of the thickness of the first transparent conductive sublayer to the thickness of the second transparent conductive sublayer is (4 to 22):1. The transmittance of the first transparent conductive sublayer is greater than the transmittance of the second transparent conductive sublayer. The transmittance of the second transparent conductive sublayer is greater than or equal to 90%. The second transparent conductive sublayer is in ohmic contact with the first metal electrode, and the contact resistance between the second transparent conductive sublayer and the first metal electrode is less than or equal to 1.5ohm.

[0008] As an optional implementation manner, in an embodiment of the present invention, the transmittance of the first transparent conductive sub-layer is greater than or equal to 92%.

[0009] As an optional embodiment, in an embodiment of the present invention, the material of the first transparent conductive sublayer is indium tin oxide or indium zinc oxide; and / or, the material of the second transparent conductive sublayer is indium cerium oxide or indium tungsten oxide; and / or, the material of the first metal electrode is any one of silver, platinum, copper, aluminum and zinc.

[0010] As an optional embodiment, in an embodiment of the present invention, when the material of the first transparent conductive sub-layer is indium zinc oxide, the mass ratio of indium oxide to zinc oxide is 90~99:1~10, and when the material of the second transparent conductive sub-layer is indium cerium oxide, the mass ratio of indium oxide to cerium oxide is 97~99:1~3.

[0011] As an optional implementation, in an embodiment of the present invention, when the solar cell includes a perovskite layer, the material of the first transparent conductive sublayer is indium zinc oxide.

[0012] As an optional implementation, in an embodiment of the present invention, the thickness of the first transparent conductive sub-layer is 80 nm to 110 nm, and the thickness of the second transparent conductive sub-layer is 5 nm to 20 nm.

[0013] As an optional embodiment, in an embodiment of the present invention, the electron mobility of the first transparent conductive sublayer is 35 cm 2 / V·s~50cm 2 / V·s, the resistivity is 4×10 -4 ohm·cm~3×10 -3 ohm·cm; and / or, the mobility of the second transparent conductive sublayer is 80cm 2 / V·s~150cm 2 / V·s, and the resistivity is less than 4×10 -4 ohm·cm.

[0014] As an optional embodiment, in an embodiment of the present invention, the contact resistance between the second transparent conductive sublayer and the first metal electrode is less than 0.5 ohm, and the mobility of the second transparent conductive sublayer is 120 cm 2 / V·s~150cm 2 / V·s, and the resistivity is less than 2.5×10 -4 ohm·cm.

[0015] As an optional embodiment, in an embodiment of the present invention, the perovskite solar cell is a perovskite tandem solar cell, which includes a silicon base cell and a composite layer, a first transport layer, a perovskite layer, a second transport layer and a buffer layer stacked in sequence on the silicon base cell, the first transparent conductive sublayer and the second transparent conductive sublayer are stacked in sequence on the buffer layer, one of the first transport layer and the second transport layer is an electron transport layer, and the other is a hole transport layer, and also includes a second metal electrode, which forms an ohmic contact with the silicon base cell.

[0016] As an optional embodiment, in an embodiment of the present invention, the perovskite solar cell is a single-junction perovskite solar cell, which also includes a transparent conductive substrate and a first transport layer, a perovskite layer, a second transport layer, and a buffer layer stacked in sequence on the transparent conductive substrate, the first transparent conductive sublayer and the second transparent conductive sublayer are stacked in sequence on the buffer layer, one of the first transport layer and the second transport layer is an electron transport layer, and the other is a hole transport layer, and also includes a second metal electrode, which forms an ohmic contact with the silicon substrate cell.

[0017] In a second aspect, an embodiment of the present invention provides a method for preparing a solar cell.

[0018] The preparation method of the solar cell comprises the following steps:

[0019] Prepare a transparent conductive layer: prepare a first transparent conductive sublayer, and prepare a second transparent conductive sublayer on the first transparent conductive sublayer:

[0020] Preparing a first metal electrode: Preparing a first metal electrode on the second transparent conductive sublayer so that the second transparent conductive sublayer forms an ohmic contact with the first metal electrode.

[0021] As an optional embodiment, in an embodiment of the present invention, the first transparent conductive sublayer is prepared by magnetron sputtering, the sputtering pressure is 0.3Pa~0.8Pa, the temperature is 20°C~100°C, the flow rate of the argon gas is 200Sccm~900Sccm, the ratio of the oxygen flow rate to the argon flow rate is 1.5%~6%, and the power density is 0.5kW / m2~6kW / m2; and / or,

[0022] The second transparent conductive sublayer is prepared by magnetron sputtering or plasma deposition process. When the second transparent conductive sublayer is prepared by plasma deposition process, the pressure of plasma deposition is 0.3Pa~0.8Pa, the temperature is 20℃~100℃, the flow rate of the argon gas is 50Sccm~200Sccm, the ratio of the oxygen flow rate to the argon flow rate is 5%~25%, the current is 100A~170A, and the top target speed is 0.3mm / s~0.5mm / s.

[0023] As an optional implementation, in an embodiment of the present invention, water vapor and hydrogen are also introduced during the preparation of the second transparent conductive sublayer. The water vapor flow rate is 1 Sccm to 5 Sccm, and the hydrogen accounts for 0.5% to 2.8% of the total flow rate of argon and oxygen.

[0024] As an optional embodiment, in an embodiment of the present invention, the perovskite solar cell is a perovskite tandem solar cell, and the preparation method of the perovskite tandem solar cell comprises the following steps:

[0025] Provide silicon substrate cells;

[0026] preparing a composite layer on the silicon substrate cell,

[0027] preparing a first transmission layer on the composite layer;

[0028] preparing a perovskite layer on the first transport layer;

[0029] preparing a second transport layer on the perovskite layer;

[0030] preparing a buffer layer on the second transmission layer;

[0031] preparing the transparent conductive layer on the buffer layer;

[0032] preparing a second metal electrode on the silicon substrate battery;

[0033] One of the first transport layer and the second transport layer is an electron transport layer, and the other is a hole transport layer.

[0034] As an optional embodiment, in an embodiment of the present invention, the perovskite solar cell is a single-junction perovskite solar cell, and the preparation method of the single-junction perovskite solar cell comprises the following steps:

[0035] providing a transparent conductive substrate;

[0036] preparing a first transmission layer on the transparent conductive substrate;

[0037] preparing a perovskite layer on the first transport layer;

[0038] preparing a second transport layer on the perovskite layer;

[0039] preparing a buffer layer on the second transmission layer;

[0040] preparing a second metal electrode on the transparent conductive substrate;

[0041] One of the first transport layer and the second transport layer is an electron transport layer, and the other is a hole transport layer.

[0042] In a third aspect, an embodiment of the present invention provides a photovoltaic module.

[0043] A photovoltaic module comprises the solar cell as mentioned in the first aspect or the solar cell prepared by the preparation method as mentioned in the second aspect.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] A solar cell provided by an embodiment of the present invention divides the transparent conductive layer in the solar cell into two layers: a first transparent conductive sublayer and a second transparent conductive sublayer. The first transparent conductive sublayer has a better light transmittance and adopts a higher film thickness, so that the film thickness of the first transparent conductive sublayer is significantly greater than that of the second transparent conductive sublayer. The thickness ratio of the first transparent conductive sublayer to the second transparent conductive sublayer is specifically limited to (4-22):1. The first transparent conductive sublayer mainly functions to improve light transmission. The contact resistance between the second transparent conductive sublayer and the first metal electrode is less than 1.5 ohms. The main function is to reduce the contact potential difference with the first metal electrode, forming a more optimal ohmic contact, thereby reducing the series resistance and increasing the lateral conductivity. The light transmittance requirement of the second transparent conductive sublayer is relatively low, and it can be greater than 90%. In combination with the first transparent conductive sublayer with the above-mentioned thickness ratio, it can promote the improvement of the overall light transmittance of the transparent conductive layer. Therefore, by combining the first transparent conductive sublayer and the second transparent conductive sublayer, the overall transmittance of the transparent conductive layer and the contact resistance with the first metal electrode are optimized, taking into account the overall balance between transmittance and conductivity, and significantly improving the fill factor while ensuring the short-circuit current of the solar cell, thereby significantly improving the conversion efficiency of the cell.

[0046] If the thickness ratio of the first transparent conductive sublayer to the second transparent conductive sublayer is reduced, that is, the thickness of the first transparent conductive sublayer is reduced or the thickness of the second transparent conductive sublayer is increased, the optical transmittance of the entire transparent conductive layer is likely to be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0048] FIG1 is a schematic structural diagram of a solar cell disclosed in an embodiment of the present invention.

[0049] Icons: 11. N-type silicon wafer; 12. First intrinsic amorphous silicon layer; 13. Second intrinsic amorphous silicon layer; 14. N-type doped crystalline silicon layer; 15. P-type doped crystalline silicon layer; 16. Second indium tin oxide composite layer; 21. First indium tin oxide composite layer; 22. Hole transport layer; 23. Perovskite layer; 24. Electron transport layer; 25. Buffer layer; 26. Transparent conductive layer; 261. First transparent conductive sublayer; 262. Second transparent conductive sublayer; 27. Anti-reflection layer; 28. First metal electrode; 29. ​​Second metal electrode. DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0051] The terms "installed," "disposed," "provided with," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; or internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0052] Furthermore, the terms "first," "second," etc., are primarily used to distinguish between different devices, elements, or components (which may or may not be of the same type and configuration), and are not intended to indicate or imply the relative importance or quantity of the devices, elements, or components indicated. Unless otherwise specified, "plurality" means two or more.

[0053] It is difficult to achieve both light transmittance and contact resistance of transparent conductive layer materials at the same time. Currently, transparent conductive layers generally consider using highly light-transmitting materials as transparent conductive layers to improve the optical transmittance of the transparent conductive layer, while ignoring the contact between the transparent conductive layer and the metal electrode. As a result, the contact resistance between the transparent conductive layer and the metal electrode is relatively large, making it difficult to simultaneously improve the short-circuit current and fill factor of the solar cell.

[0054] In order to solve the above problems and achieve simultaneous improvement of the short-circuit current and fill factor of solar cells, the present invention provides a solar cell and a preparation method thereof, and a photovoltaic module.

[0055] The technical solution of the present invention will be further described below in conjunction with embodiments and drawings.

[0056] In a first aspect, an embodiment of the present invention provides a solar cell.

[0057] Referring to Figure 1, the solar cell includes a transparent conductive layer and a first metal electrode disposed on the transparent conductive layer. The thickness of the transparent conductive layer is 85nm to 130nm. The transparent conductive layer includes a first transparent conductive sublayer and a second transparent conductive sublayer stacked together. The ratio of the thickness of the first transparent conductive sublayer to the thickness of the second transparent conductive sublayer is (4-22):1. The transmittance of the first transparent conductive sublayer is greater than the transmittance of the second transparent conductive sublayer. The transmittance of the second transparent conductive sublayer is greater than or equal to 90%. The second transparent conductive sublayer is in ohmic contact with the first metal electrode, and the contact resistance between the second transparent conductive sublayer and the first metal electrode is less than or equal to 1.5ohm.

[0058] The present invention divides the transparent conductive layer into two layers: a first transparent conductive sublayer and a second transparent conductive sublayer. The first transparent conductive sublayer has a better light transmittance. At the same time, the film thickness of the first transparent conductive sublayer is significantly greater than that of the second transparent conductive sublayer. The thickness ratio of the first transparent conductive sublayer to the second transparent conductive sublayer is specifically limited to (4-22):1. The main function of the first transparent conductive sublayer is to improve the transmittance of light. The contact resistance between the second transparent conductive sublayer and the first metal electrode is less than 1.5 ohms. The main function is to reduce the contact potential difference with the first metal electrode, forming a better ohmic contact, thereby reducing the series resistance and increasing the lateral conductivity. The light transmittance of the second transparent conductive sublayer is required to be lower than that of the first transparent conductive sublayer, and can be greater than 90%. In combination with the first transparent conductive sublayer with the above thickness ratio, it can promote the improvement of the overall light transmittance of the transparent conductive layer. Therefore, through the combination of the above-mentioned first transparent conductive sublayer and the second transparent conductive sublayer, the overall transmittance of the transparent conductive layer and the contact resistance with the first metal electrode are optimized, and the balance between transmittance and conductivity is taken into account as a whole. The fill factor is significantly improved while ensuring the short-circuit current of the solar cell, thereby significantly improving the conversion efficiency of the cell.

[0059] If the thickness ratio of the first transparent conductive sublayer to the second transparent conductive sublayer is reduced, that is, the thickness of the first transparent conductive sublayer is too low or the thickness of the second transparent conductive sublayer is too high, the optical transmittance of the entire transparent conductive layer will be easily reduced, which is not conducive to improving the energy conversion efficiency of the solar cell.

[0060] If the ratio of the thickness of the first transparent conductive sublayer to the second transparent conductive sublayer is too high, that is, the thickness of the first transparent conductive sublayer is too high or the thickness of the second transparent conductive sublayer is too low, it is easy to cause the contact resistance between the second transparent conductive sublayer and the first metal electrode to increase and the fill factor to decrease, which is not conducive to improving the energy conversion efficiency of the solar cell.

[0061] For example, the thickness of the transparent conductive layer can be 85 nm, 90 nm, 95 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, etc. The ratio of the thickness of the first transparent conductive sublayer to the thickness of the second transparent conductive sublayer can be 4:1, 5:1, 6:1, 8:1, 10:1, 12:1, 15:1, 20:1, 22:1, etc.

[0062] The light transmittance of the second transparent conductive sub-layer may be 90%, 91%, 92%, 93%, 94% or other values ​​and ranges.

[0063] The contact resistance between the second transparent conductive sublayer and the first metal electrode can be 1.5ohm, 1.4ohm, 1.3ohm, 1.2ohm, 1.1ohm, 1ohm, 0.9ohm, 0.8ohm, 0.7ohm, 0.6ohm and 0.5ohm, etc.

[0064] In some embodiments, the light transmittance of the first transparent conductive sub-layer is greater than or equal to 92%.

[0065] Experiments have found that by combining a first transparent conductive sublayer with a transmittance greater than or equal to 92% with a second transparent conductive sublayer, the overall transmittance of the transparent conductive layer is better improved, while maintaining a lower contact resistance, which is more conducive to improving the photoelectric conversion efficiency of solar cells.

[0066] Illustratively, the light transmittance of the first transparent conductive sub-layer may be 92%, 93%, 94%, 95% or other values ​​and ranges.

[0067] In some embodiments, the material of the first transparent conductive sublayer is indium tin oxide or indium zinc oxide.

[0068] In some embodiments, the material of the second transparent conductive sublayer is indium cerium oxide or indium tungsten oxide.

[0069] In some embodiments, the material of the first metal electrode is any one of silver, platinum, copper, aluminum and zinc.

[0070] The material of the first transparent conductive sublayer is indium tin oxide or indium zinc oxide. Indium tin oxide and indium zinc oxide have good light transmittance, which is conducive to obtaining a first transparent conductive sublayer with good light transmittance.

[0071] The material of the second transparent conductive sublayer is indium cerium oxide or indium tungsten oxide. Indium cerium oxide or indium tungsten oxide has a low resistivity and a low contact potential difference with the first metal electrode, which plays an important role in reducing the contact resistance between the second transparent conductive sublayer and the first metal electrode, and can achieve a contact resistance between the second transparent conductive sublayer and the first metal electrode of less than 1.5 ohm.

[0072] When the first transparent conductive material is indium tin oxide or indium zinc oxide, and the material of the second transparent conductive sublayer is indium cerium oxide or indium tungsten oxide, two different transparent conductive layer materials can be selected to construct a double-layer transparent conductive layer with excellent performance, while achieving an improvement in the overall light transmittance of the transparent conductive layer and a reduction in the contact resistance, thereby simultaneously improving the short-circuit current and fill factor of the battery.

[0073] The material of the metal electrode can generally be silver, platinum, copper, aluminum or zinc. The material of the first metal electrode of the present invention can be selected from any one of silver, platinum, copper, aluminum and zinc.

[0074] In some embodiments, when the material of the first transparent conductive sub-layer is indium zinc oxide, the mass ratio of indium oxide to zinc oxide is 90-99:1-10.

[0075] In some embodiments, when the material of the second transparent conductive sub-layer is indium cerium oxide, the mass ratio of indium oxide to cerium oxide is 97-99:1-3.

[0076] When the mass ratio of indium oxide to zinc oxide in the indium zinc oxide material of the first transparent conductive sublayer is 90-99:1-10, the indium zinc oxide obtained at this time has excellent light transmittance. Combined with the specific film thickness ratio of the first transparent conductive sublayer and the second transparent conductive sublayer, the transmittance of the transparent conductive layer is effectively controlled, thereby promoting the light transmittance of the transparent conductive layer to a high level.

[0077] When the mass ratio of indium oxide to cerium oxide in the indium cerium oxide material of the second transparent conductive sub-layer is 97-99:1-3, on the one hand, the indium cerium oxide at this mass ratio has excellent contact characteristics with the first metal electrode, and its resistivity is significantly lower than that of the first transparent conductive layer. Therefore, the second transparent conductive sub-layer and the first metal electrode have a lower contact potential difference, which can effectively reduce the contact resistance between the transparent conductive layer and the first metal electrode.

[0078] For example, in indium zinc oxide, the mass ratio of indium oxide to zinc oxide may be 90:10, 92:8, 94:6, 95:5, 97:3, 98:2, 99:1, etc. In indium cerium oxide, the mass ratio of indium oxide to cerium oxide may be 97:3, 98:2, 99:1, etc.

[0079] In some embodiments, when the solar cell includes a perovskite layer, the material of the first transparent conductive sublayer is indium zinc oxide.

[0080] When a solar cell includes a perovskite layer, the perovskite material in the perovskite layer is an ionic crystal material with excellent light absorption and electrical conductivity, but it is also very fragile and has defects such as being not resistant to high temperatures, not resistant to light, easily hydrolyzed, easily oxidized, and prone to secondary reactions. After the perovskite layer of the solar cell is prepared, in order to protect the perovskite layer from generating more defects, the remaining other processes should be controlled to be carried out at low temperatures. The first transparent conductive sublayer is closer to the perovskite layer than the second transparent conductive sublayer. When the first transparent conductive sublayer is made of indium zinc oxide, indium zinc oxide has the characteristics of being easy to crystallize at low temperatures and can be formed at room temperature or low temperature by sputtering to form an indium zinc oxide layer with a high degree of crystallization. There is no obvious difference in optics and electrical properties between the indium zinc oxide layer and the film annealed again at high temperature. Therefore, the use of indium zinc oxide can avoid the subsequent annealing step, saving time while effectively protecting the perovskite layer from generating more defects.

[0081] In some embodiments, the thickness of the first transparent conductive sublayer is 80 nm to 110 nm, and the thickness of the second transparent conductive sublayer is 5 nm to 20 nm.

[0082] By setting the film thickness of the first transparent conductive sublayer and the second transparent conductive sublayer, it is possible to ensure that the second transparent conductive sublayer has a better contact resistance with the first metal electrode, and minimize the optical transmittance of the second transparent conductive sublayer on the overall transparent conductive layer and the impact on the material properties of the first transparent conductive sublayer.

[0083] When the thickness of the second transparent conductive sublayer is too low, the contact potential difference between the second transparent conductive sublayer and the first metal electrode increases, and the contact resistance increases. When the thickness of the second transparent conductive sublayer is too high, the transmittance of the entire transparent conductive layer decreases.

[0084] For example, the thickness of the first transparent conductive sublayer may be 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, 105 nm, 110 nm, etc.

[0085] For example, the thickness of the second transparent conductive sublayer may be 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 17 nm, 18 nm, 20 nm, etc.

[0086] In some embodiments, the electron mobility of the first transparent conductive sublayer is 35 cm 2 / V·s~50cm 2 / V·s, the resistivity is 4×10 -4 ohm·cm~3×10 -3 ohm·cm.

[0087] In some embodiments, the mobility of the second transparent conductive sublayer is 80 cm 2 / V·s~150cm 2 / V·s, and the resistivity is less than 4×10 -4 ohm·cm.

[0088] The first transparent conductive sublayer has low conductivity, while the second transparent conductive sublayer has much lower conductivity than the first transparent conductive sublayer. Combined with the transmittance and specific thickness ratio setting of the first transparent conductive sublayer and the second transparent conductive sublayer, the transparent conductive layer as a whole strikes a balance between transmittance and conductivity, thereby improving the photoelectric performance of the transparent conductive layer as a whole. While ensuring the short-circuit current of the battery, the fill factor is greatly improved, thereby greatly improving the conversion efficiency of the battery.

[0089] For example, the electron mobility of the first transparent conductive sublayer may be 35 cm 2 / V·s、38cm 2 / V·s、40cm 2 / V·s、45cm 2 / V·s、48cm 2 / V·s and 50cm 2 / V·s, etc., the resistivity can be 4×10 -4 ohm·cm、4.2×10 -4 ohm·cm、4.5×10 -4 ohm·cm、4.8×10 -4 ohm·cm, 1×10 -3 ohm·cm, 2×10 -3 ohm·cm, 3×10 -3 ohm·cm; and / or, the mobility of the second transparent conductive sublayer may be 80cm 2 / V·s、90cm 2 / V·s、100cm 2 / V·s、110cm 2 / V·s、120cm 2 / V·s、130cm 2 / V·s、140cm 2 / V·s、150cm 2 / V·s, and the resistivity is less than 4×10 -4ohm·cm, the resistivity can be 3.9×10 -4 ohm·cm、3.5×10 -4 ohm·cm、3.0×10 -4 ohm·cm、2.5×10 -4 ohm·cm, 2.0×10 -4 ohm·cm, etc.

[0090] Further preferably, the contact resistance between the second transparent conductive sublayer and the first metal electrode is less than 0.5 ohm, and the mobility of the second transparent conductive sublayer is 120 cm 2 / V·s~150cm 2 / V·s, and the resistivity is less than 2.5×10 -4 ohm·cm.

[0091] When the contact resistance between the second transparent conductive sublayer and the first metal electrode is further reduced, and the mobility and resistivity of the second transparent conductive sublayer are further improved, the resistivity is further reduced, which is conducive to further improving the conductivity of the transparent conductive layer and further reducing the contact resistance, thereby further improving the fill factor of the solar cell.

[0092] In some embodiments, the perovskite solar cell is a perovskite tandem solar cell, which includes a silicon base cell and a composite layer, a first transport layer, a perovskite layer, a second transport layer and a buffer layer stacked in sequence on the silicon base cell, the first transparent conductive sublayer and the second transparent conductive sublayer are stacked in sequence on the buffer layer, one of the first transport layer and the second transport layer is an electron transport layer, and the other is a hole transport layer, and also includes a second metal electrode, which forms an ohmic contact with the silicon base cell.

[0093] In some embodiments, the perovskite solar cell is a single-junction perovskite solar cell, which further includes a transparent conductive substrate and a first transport layer, a perovskite layer, a second transport layer, and a buffer layer stacked sequentially on the transparent conductive substrate, the first transparent conductive sublayer and the second transparent conductive sublayer are stacked sequentially on the buffer layer, one of the first transport layer and the second transport layer is an electron transport layer, and the other is a hole transport layer, and further includes a second metal electrode, which forms an ohmic contact with the silicon substrate cell.

[0094] In a second aspect, an embodiment of the present invention provides a method for preparing a solar cell.

[0095] The preparation method of the solar cell comprises the following steps:

[0096] Prepare a transparent conductive layer: prepare a first transparent conductive sublayer, and prepare a second transparent conductive sublayer on the first transparent conductive sublayer.

[0097] Prepare a first metal electrode: prepare the first metal electrode on the second transparent conductive sublayer, so that the second transparent conductive sublayer forms an ohmic contact with the first metal electrode.

[0098] The present invention first prepares a first transparent conductive sublayer with a relatively high thickness and excellent light transmittance. On the first transparent conductive sublayer, another material is selected and embedded between the first transparent conductive sublayer and the first metal electrode to improve the contact characteristics between the second transparent conductive sublayer and the first metal electrode and reduce the contact resistance between the second transparent conductive sublayer and the first metal electrode. By combining the first transparent conductive sublayer and the second transparent conductive sublayer with a specific thickness ratio, a balance between transmittance and conductivity is taken into account as a whole, and the fill factor is greatly improved while ensuring the short-circuit current of the battery, thereby greatly improving the conversion efficiency of the battery.

[0099] In some embodiments, the first transparent conductive sublayer is prepared by magnetron sputtering, the sputtering pressure is 0.3Pa~0.8Pa, the temperature is 20℃~100℃, the flow rate of argon gas is 200Sccm~900Sccm, the ratio of oxygen flow rate to argon flow rate is 1.5%~6%, and the power density is 0.5kW / m~6kW / m.

[0100] And / or, the second transparent conductive sublayer is prepared by magnetron sputtering or plasma deposition process. When the second transparent conductive sublayer is prepared by plasma deposition process, the pressure of plasma deposition is 0.3Pa~0.8Pa, the temperature is 20℃~100℃, the flow rate of argon gas is 50Sccm~200Sccm, the ratio of oxygen flow rate to argon flow rate is 5%~25%, the current is 100A~170A, and the top target speed is 0.3mm / s~0.5mm / s.

[0101] During the preparation process of the first transparent conductive sublayer, the ratio of the oxygen flow rate to the argon flow rate is controlled at 1.5% to 6%, the transparency of the first transparent conductive sublayer is improved, and the transmittance is high. If the oxygen content is too low, the transparency of the first transparent conductive sublayer is poor and the transmittance decreases. If the oxygen content is too high, the conductivity of the first transparent conductive sublayer is seriously reduced.

[0102] During the preparation process of the second transparent conductive sub-layer, the ratio of the oxygen flow rate to the argon flow rate is controlled to be 5% to 25%, the transparency of the second transparent conductive sub-layer is improved, and the transmittance is high. If the oxygen flow rate is too low, the transparency of the second transparent conductive sub-layer is poor and the transmittance decreases. If the oxygen flow rate is too high, the conductivity of the second transparent conductive sub-layer is seriously reduced.

[0103] Illustratively, during the preparation of the first transparent conductive sublayer, the sputtering pressure may be 0.3 Pa, 0.4 Pa, 0.5 Pa, 0.6 Pa, 0.7 Pa, and 0.8 Pa; the temperature may be 20° C., 30° C., 40° C., 50° C., 60° C., 70° C., 80° C., 90° C., and 100° C.; the flow rate of the argon gas may be 200 Sccm, 300 Sccm, 400 Sccm, 500 Sccm, 600 Sccm, 900 Sccm, 200 Sccm, and 900 Sccm, etc.; the ratio of the oxygen flow rate to the argon flow rate may be 1.5%, 2%, 2.5, 3%, 3.5, 4%, 4.5, 5%, 5.5%, and 6%; and the power density may be 0.5 kW / m, 1 kW / m, 1.5 kW / m, 2 kW / m, 2.5 kW / m, 3 kW / m, 4 kW / m, 5 kW / m, and 6 kW / m, etc.;

[0104] In some embodiments, during the preparation of the second transparent conductive sub-layer, water vapor and hydrogen are also introduced, with the water vapor flow rate being 1 Sccm to 5 Sccm, and the hydrogen gas accounting for 0.5% to 2.8% of the total flow rate of argon and oxygen.

[0105] Water vapor and hydrogen are introduced into the second transparent conductive sublayer at the same time, and OH can be introduced at the same time as hydrogen atoms. - By introducing oxygen atoms, the increase in carrier concentration can be avoided; if only hydrogen gas is introduced, the addition of hydrogen atoms in the hydrogen gas will easily lead to an increase in the carrier concentration of the second transparent conductive sublayer, thereby reducing the transmittance of light at long waves. If only water vapor is introduced, less water will provide fewer hydrogen atoms, but if more water vapor is introduced, the second transparent conductive layer after film formation will absorb water vapor, and the contact with the electrode will become worse. At the same time, introducing too much water vapor will cause the perovskite layer to be unstable, leading to degradation.

[0106] During the preparation of the second transparent conductive sublayer, water vapor and hydrogen are introduced simultaneously. The H atoms formed by hydrogen during the film formation process will enter the second transparent conductive sublayer. On the one hand, this improves the reduction ability of the second transparent conductive sublayer and prevents the oxidation of the first metal electrode at the contact interface between the second transparent conductive sublayer and the first metal electrode, thereby overcoming the problem that the first metal electrode is easily oxidized and the contact resistance between the second transparent conductive sublayer and the oxidized first metal electrode is easily increased. On the other hand, it can passivate the crystal defects of the second transparent conductive sublayer. The reduction of defects can further improve the electron mobility of the second transparent conductive sublayer and reduce the resistivity of the second conductive sublayer, thereby reducing the contact resistance between the second conductive sublayer and the first metal electrode.

[0107] In addition, H formed by water vapor during film formation + and OH - Entering the second transparent conductive sublayer, H +It can prevent the oxidation of the first metal electrode and passivate the crystal defects of the second transparent conductive sublayer. - It can terminate the oxygen vacancies in the second transparent conductive sublayer, reduce crystal defects, and + They work together to improve the electron mobility of the second transparent conductive sub-layer and reduce the resistivity.

[0108] By combining the water vapor and hydrogen, the electron mobility of the second transparent conductive sublayer increases to 120 cm 2 / V·s~150cm 2 / V·s, and the resistivity is less than 2.5×10 -4 ohm·cm, optical transmittance greater than 90%, and contact resistance with metal electrodes less than 0.5ohm.

[0109] Illustratively, the water vapor flow rate is 1 Sccm, 2 Sccm, 3 Sccm, 4 Sccm, and 5 Sccm, and the hydrogen gas accounts for 0.5%, 1%, 1.5%, 2%, 2.5%, and 2.8% of the sum of the argon and oxygen flow rates.

[0110] In some embodiments, the perovskite solar cell is a perovskite tandem solar cell, and the preparation method of the perovskite tandem solar cell comprises the following steps:

[0111] Provide silicon substrate cells.

[0112] The composite layer is prepared on the silicon substrate cell.

[0113] A first transmission layer is prepared on the composite layer.

[0114] A perovskite layer is formed on the first transport layer.

[0115] A second transport layer is fabricated on the perovskite layer.

[0116] A buffer layer is formed on the second transmission layer.

[0117] A transparent conductive layer is prepared on the buffer layer.

[0118] A second metal electrode is prepared on the silicon substrate cell.

[0119] One of the first transport layer and the second transport layer is an electron transport layer, and the other is a hole transport layer.

[0120] In some embodiments, the perovskite solar cell is a single-junction perovskite solar cell, and the preparation method of the single-junction perovskite solar cell comprises the following steps:

[0121] A transparent conductive substrate is provided.

[0122] A first transmission layer is prepared on a transparent conductive substrate.

[0123] A perovskite layer is formed on the first transport layer.

[0124] A second transport layer is fabricated on the perovskite layer.

[0125] A buffer layer is formed on the second transmission layer.

[0126] A second metal electrode is prepared on the transparent conductive substrate.

[0127] One of the first transport layer and the second transport layer is an electron transport layer, and the other is a hole transport layer.

[0128] In a third aspect, an embodiment of the present invention provides a photovoltaic module.

[0129] A photovoltaic module comprises the solar cell as mentioned in the first aspect or the solar cell prepared by the preparation method as mentioned in the second aspect.

[0130] The technical solution of the present invention will be further described below in conjunction with more specific embodiments and drawings.

[0131] Example 1

[0132] An embodiment of the present invention provides a perovskite tandem solar cell, comprising:

[0133] N-type silicon wafer.

[0134] A first intrinsic amorphous silicon layer is stacked on the light-receiving surface of the N-type silicon wafer.

[0135] A second intrinsic amorphous silicon layer is stacked on the backlight surface of the N-type silicon wafer.

[0136] An N-type doped crystalline silicon layer is stacked on the first intrinsic amorphous silicon layer and is away from the light-receiving surface of the N-type silicon wafer.

[0137] A P-type doped crystalline silicon layer is stacked on the second intrinsic amorphous silicon layer and is away from the backlight surface of the N-type silicon wafer.

[0138] A first indium tin oxide composite layer is stacked on the N-type doped crystalline silicon layer away from the light-receiving surface of the N-type silicon wafer.

[0139] A second indium tin oxide composite layer is stacked on the P-type doped crystalline silicon layer away from the backlight surface of the N-type silicon wafer.

[0140] A hole transport layer is stacked on the first indium tin oxide composite layer and is away from the light-receiving surface of the N-type silicon wafer.

[0141] The perovskite layer is stacked on the hole transport layer away from the light-receiving surface of the N-type silicon wafer.

[0142] The electron transport layer is stacked on the perovskite layer away from the light-receiving surface of the N-type silicon wafer.

[0143] A buffer layer is stacked on the electron transport layer and is away from the light-receiving surface of the N-type silicon wafer.

[0144] A transparent conductive layer is stacked on the buffer layer away from the light-receiving surface of the N-type silicon wafer, and the transparent conductive layer includes a first transparent conductive sublayer and a second transparent conductive sublayer. The first transparent conductive sublayer is stacked on the buffer layer away from the light-receiving surface of the N-type silicon wafer, the material of the first transparent conductive sublayer is indium zinc oxide, the mass ratio of indium oxide to zinc oxide in indium zinc oxide is 90:10, and the thickness of the first transparent conductive sublayer is 100nm. The second transparent conductive sublayer is stacked on the first transparent conductive sublayer, the material of the second transparent conductive sublayer is indium cerium oxide, the mass ratio of indium oxide to cerium oxide in indium cerium oxide is 97:3, and the thickness of the second transparent conductive sublayer is 10nm.

[0145] An anti-reflection layer is stacked on the second transparent conductive sub-layer.

[0146] A first metal electrode and a second metal electrode, the first metal electrode is a negative electrode, the second metal electrode is a positive electrode, both the positive electrode and the negative electrode are silver electrodes, the negative electrode forms an ohmic contact with the second transparent conductive sublayer, and the positive electrode forms an ohmic contact with the second indium tin oxide composite layer.

[0147] The method for preparing the above-mentioned perovskite tandem solar cell comprises the following steps:

[0148] Provide N-type silicon wafers.

[0149] A first intrinsic amorphous silicon layer is prepared on the light-receiving side of the N-type silicon wafer, and a second intrinsic amorphous silicon layer is prepared on the backlight side of the N-type silicon wafer.

[0150] An N-type doped crystalline silicon layer is prepared on the first intrinsic amorphous silicon layer, and a P-type doped crystalline silicon layer is prepared on the second intrinsic amorphous silicon layer.

[0151] A first indium tin oxide composite layer is prepared on the N-type doped crystalline silicon layer by adopting a radio frequency magnetron sputtering process, and a second indium tin oxide composite layer is prepared on the P-type doped crystalline silicon layer by adopting a radio frequency magnetron sputtering process.

[0152] A hole transport layer is prepared on the first indium tin oxide composite layer.

[0153] A perovskite layer is prepared on the hole transport layer.

[0154] An electron transport layer is prepared on the perovskite layer.

[0155] A buffer layer is formed on the electron transport layer.

[0156] A transparent conductive layer is prepared on the buffer layer. The preparation method of the transparent conductive layer includes the following steps:

[0157] Preparation of the first transparent conductive sub-layer: an indium zinc oxide target material was selected, and the mass ratio of indium oxide to zinc oxide in the indium zinc oxide target material was 90:10. The first transparent conductive sub-layer was prepared on the buffer layer by radio frequency magnetron sputtering, wherein the sputtering pressure was 0.5 Pa, the temperature was 25°C, the flow rate of the argon gas was 500 Sccm, the ratio of the oxygen flow rate to the argon flow rate was 3%, and the target sputtering power density of the rotating cathode was 0.55 KW / m.

[0158] Preparation of the second transparent conductive sub-layer: an indium oxide cerium target material was selected, and the mass ratio of indium oxide to cerium oxide in the indium oxide cerium target material was 97:3. The second transparent conductive sub-layer was prepared on the first transparent conductive sub-layer by a reactive plasma deposition process, wherein the pressure of the plasma deposition was 0.5 Pa, the temperature was 25°C, the flow rate of the argon gas was 100 Sccm, the ratio of the oxygen flow rate to the argon flow rate was 10%, the coil current of the electron gun was 145 A, and the top target speed was 0.4 mm / s.

[0159] An anti-reflection layer is prepared on the second transparent conductive sub-layer.

[0160] Prepare positive and negative electrodes.

[0161] Example 2

[0162] The embodiment of the present invention provides a perovskite tandem solar cell, which differs from the first embodiment in that the thickness of the first transparent conductive sublayer is 90 nm, the thickness of the second transparent conductive sublayer is 20 nm, and the rest is consistent with the first embodiment.

[0163] Example 3

[0164] The embodiment of the present invention provides a perovskite tandem solar cell, which differs from the first embodiment in that the thickness of the first transparent conductive sublayer is 80 nm, the thickness of the second transparent conductive sublayer is 5 nm, and the rest is consistent with the first embodiment.

[0165] Example 4

[0166] The embodiment of the present invention provides a perovskite tandem solar cell, which differs from the first embodiment in that the material of the first transparent conductive sublayer is indium tin oxide, and the mass ratio of indium oxide to tin oxide in the indium tin oxide is 90:10. The rest is consistent with the first embodiment.

[0167] Example 5

[0168] The embodiment of the present invention provides a perovskite tandem solar cell, which differs from the first embodiment in that the material of the first transparent conductive sublayer is indium tin oxide, and the mass ratio of indium oxide to tin oxide in the indium tin oxide is 97:3. The rest is consistent with the first embodiment.

[0169] Example 6

[0170] The embodiment of the present invention provides a perovskite tandem solar cell, which differs from the first embodiment in that the material of the second transparent conductive sublayer is indium tungsten oxide, and the mass ratio of indium oxide to tungsten oxide in the indium tungsten oxide is 97:3. The rest is consistent with the first embodiment.

[0171] Example 7

[0172] An embodiment of the present invention provides a perovskite tandem solar cell, which differs from Example 1 in that: in the step of preparing the first transparent conductive sublayer, the ratio of oxygen flow rate to argon flow rate is 6%, and in the step of preparing the second transparent conductive sublayer, the ratio of oxygen flow rate to argon flow rate is 20%, and the rest remains consistent with Example 1.

[0173] Example 8

[0174] An embodiment of the present invention provides a perovskite tandem solar cell, which differs from Example 1 in that: in the step of preparing the second transparent conductive sub-layer, argon, oxygen, H2 and H20 are introduced, the argon flow rate introduced into the process chamber is 100 Sccm, the ratio of the oxygen flow rate to the argon flow rate is 17%, the H2O flow rate is 3 Sccm, and H2 accounts for 1% of the total argon and oxygen flow rates. The rest remains consistent with Example 1.

[0175] Comparative Example 1

[0176] The comparative example of the present invention provides a perovskite tandem solar cell, which differs from the first embodiment in that the transmittance of the first transparent conductive sublayer is less than 92%, and the transmittance of the first transparent conductive sublayer is less than the transmittance of the second transparent conductive sublayer.

[0177] Specifically, in the step of preparing the first transparent conductive sublayer, the ratio of oxygen flow rate to argon flow rate is 1%, and in the step of preparing the second transparent conductive sublayer, the ratio of oxygen flow rate to argon flow rate is 20%, and the rest is consistent with the first embodiment.

[0178] Comparative Example 2

[0179] The comparative example of the present invention provides a perovskite tandem solar cell, which differs from the first embodiment in that the thickness of the first transparent conductive sublayer is 85 nm, the thickness of the second transparent conductive sublayer is 25 nm, and the rest is consistent with the first embodiment.

[0180] Comparative Example 3

[0181] The comparative example of the present invention provides a perovskite tandem solar cell, which differs from the first embodiment in that the thickness of the first transparent conductive sublayer is 106 nm, the thickness of the second transparent conductive sublayer is 4 nm, and the rest is consistent with the first embodiment.

[0182] Comparative Example 4

[0183] The comparative example of the present invention provides a perovskite tandem solar cell, which differs from Example 1 in that: the material of the first transparent conductive sublayer is indium cerium oxide, and the mass ratio of indium oxide to cerium oxide in the indium cerium oxide target is 97:3; the material of the second transparent conductive sublayer is indium zinc oxide, and the mass ratio of indium oxide to zinc oxide in indium zinc oxide is 90:10. The rest is consistent with Example 1.

[0184] Experiment 1

[0185] The transmittance, resistivity, and carrier mobility of the first transparent conductive sublayer and the second transparent conductive sublayer are tested. The transmittance test method is as follows:

[0186] Hitachi UV / Vis / Near Infrared spectrophotometer was used to test the optical properties of the transparent conductive layer. The test conditions were: the test wavelength range was 350nm~1200nm, and the test environment temperature was 25°C. A barium sulfate white board was used to calibrate the machine before the test. The performance tests were light transmittance and light reflectance. T represents light transmittance, in %, and R represents light reflectance, in %. In this application, the transmittance Tte=T / (1-R)*100%, and its value is taken as the average value at a wavelength of 350nm~1200nm; in order to characterize the transmittance of different transparent conductive layer materials and prevent variables, the optical transmittance test was tested at a transparent conductive layer film thickness of 110nm;

[0187] The test methods for resistivity and carrier mobility are:

[0188] A Swin Hall effect tester was used to test the resistivity and carrier mobility of the transparent conductive layer. The test conditions were: transparent conductive layer thickness 110nm, sample size 10mm×10mm, and test environment temperature 25°C. Calibration was performed using standard components before testing. The performance tests were resistivity and carrier mobility. Rs represents the film resistivity in ohm.cm, and Mob represents the carrier mobility in cm. 2 / V·s.

[0189] The test results are recorded in Table 1.

[0190] Table 1

[0191] Experiment 2

[0192] Contact resistance test

[0193] The contact resistance between the second transparent electrode layer and the metal electrode in the above embodiments and comparative examples was tested using the following method:

[0194] The contact resistance performance between the transparent electrode layer and the metal electrode was tested using a PVtools contact resistance tester. The test conditions were: a metal electrode width of 50 μm, a sample width of 10 mm, and an ambient temperature of 25°C. Calibration was performed using standard components before testing. The performance test was for contact resistance. Contact resistance represents contact resistance, measured in ohms.

[0195] The test results are recorded in Table 2.

[0196] Experiment 3

[0197] The performance of perovskite solar cells was tested using a Wavelabs solar simulator under the following conditions: AM1.5, 1000W / m 2 The test environment temperature was 25°C. Before testing, the simulated sunlight intensity of the light source was calibrated using a standard silicon cell. Performance tests included energy conversion efficiency, open circuit voltage, short circuit current, and fill factor. PCE represents energy conversion efficiency (%, %), and Jsc represents short circuit current density (mA / cm2). 2 , FF stands for fill factor, unit is %.

[0198] The test results are recorded in Table 2.

[0199] Table 2

[0200] Combining the data comparison of Example 1 and Comparative Example 1 in Table 1 and Table 2, it can be seen that compared with Comparative Example 1, the energy conversion efficiency of Example 1 is increased by 0.87%, and the short-circuit current is increased by 0.02 mA / cm 2 , the fill factor is increased by 2.26%, and the contact resistance is reduced by 0.55ohm, which proves that when the transmittance of the first transparent conductive sub-layer is increased to more than 92%, and the first transparent conductive sub-layer with lower transmittance is composited with the second transparent conductive sub-layer with higher transmittance, it is not only beneficial to reduce the contact resistance between the second transparent conductive sub-layer and the metal electrode, but also can give full play to the composite advantages of the first transparent conductive layer and the second transparent conductive layer, significantly improving the energy conversion efficiency of the solar cell.

[0201] From the data comparison of Example 1 and Comparative Example 2 in Table 1 and Table 2, it can be seen that compared with Comparative Example 2, the energy conversion efficiency of Example 1 is increased by 0.7%, and the short-circuit current is increased by 0.25 mA / cm 2, the fill factor increased by 0.98%, and the contact resistance decreased by 0.09 ohm, proving that the ratio of the thickness of the first transparent conductive sublayer to the thickness of the second transparent conductive layer is greater than 4, the synergistic effect of the first transparent conductive sublayer and the second transparent conductive sublayer is excellent, and the improvement effect of the short-circuit current and the fill factor is significant, which can better improve the energy conversion efficiency of the solar cell. Combining the data comparison of Example 1 and Comparative Example 3, it can be seen that compared with Comparative Example 3, the energy conversion efficiency of Example 1 is increased by 0.59%, and the short-circuit current is reduced by 0.05 mA / cm 2 , the fill factor increased by 1.19%, and the contact resistance decreased by 0.4 ohm, demonstrating that when the ratio of the thickness of the first transparent conductive sublayer to the thickness of the second transparent conductive layer is less than 22, the first transparent conductive sublayer and the second transparent conductive layer have an excellent synergistic effect, which can simultaneously increase the fill factor and reduce the contact resistance, thereby improving the conversion efficiency of the solar cell. When the ratio of the thickness of the first transparent conductive sublayer to the thickness of the second transparent conductive layer is less than 4 or greater than 22, the combination of the first transparent conductive layer and the second transparent conductive layer is less effective, making it difficult to simultaneously increase the fill factor or short-circuit current and reduce the contact resistance, resulting in lower conversion efficiency of the solar cell.

[0202] From the data comparison between Example 1 and Comparative Example 4 in Table 1 and Table 2, it can be seen that compared with Comparative Example 3, the energy conversion efficiency of Example 1 is improved by 1.11%, and the short-circuit current is improved by 0.09 mA / cm 2 , the fill factor is increased by 2.67%, and the contact resistance is reduced by 0.9 ohm, which proves that the first transparent conductive sub-layer with lower transmittance is combined with the second transparent conductive sub-layer with higher transmittance, and the resistivity of the second transparent conductive sub-layer is made higher than the mobility of the first transparent conductive sub-layer. The synergistic effect of the first transparent conductive sub-layer and the second transparent conductive sub-layer is stronger, and the fill factor and contact resistance are reduced more significantly, thereby significantly improving the energy conversion efficiency of the solar cell.

[0203] The solar cells, preparation methods, and photovoltaic modules disclosed in the embodiments of the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only intended to help understand the solar cells, preparation methods, photovoltaic modules, and their core concepts of the present invention. At the same time, for those skilled in the art, according to the concepts of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A solar cell, characterized in that, It includes a transparent conductive layer and a first metal electrode disposed on the transparent conductive layer. The thickness of the transparent conductive layer is 85 nm to 130 nm. The transparent conductive layer includes a first transparent electron-conducting layer and a second transparent electron-conducting layer stacked on top of each other. The ratio of the thickness of the first transparent electron-conducting layer to the thickness of the second transparent electron-conducting layer is (4 to 22):

1. The light transmittance of the first transparent electron-conducting layer is greater than that of the second transparent electron-conducting layer. The light transmittance of the second transparent electron-conducting layer is greater than or equal to 90%. The second transparent electron-conducting layer is in ohmic contact with the first metal electrode, and the contact resistance between the second transparent electron-conducting layer and the first metal electrode is less than or equal to 1.5 ohm.

2. The solar cell according to claim 1, characterized in that, The light transmittance of the first transparent electron-conducting layer is greater than or equal to 92%.

3. The solar cell according to claim 1, wherein The material of the first transparent electron-conducting layer is indium tin oxide or indium zinc oxide.

4. The solar cell according to claim 1, characterized in that, The material of the second transparent electron-conducting layer is indium cerium oxide or indium tungsten oxide.

5. The solar cell according to claim 1, characterized in that, The material of the first metal electrode is any one of silver, platinum, copper, aluminum, and zinc.

6. The solar cell according to claim 3, characterized in that, When the solar cell includes a perovskite layer, the material of the first transparent electron-conducting layer is indium zinc oxide.

7. The solar cell according to any one of claims 1 to 6, characterized in that, When the material of the first transparent electron-conducting layer is indium zinc oxide, the mass ratio of indium to zinc oxide is 90 to 99:1 to 10.

8. The solar cell according to any one of claims 1 to 7, characterized in that, When the material of the second transparent electron-conducting layer is indium cerium oxide, the mass ratio of indium to indium cerium oxide is 97 to 99:1 to 3.

9. The solar cell according to any one of claims 1 to 8, characterized in that, The thickness of the first transparent electron-conducting layer is 80 nm to 110 nm.

10. The solar cell according to any one of claims 1 to 9, characterized in that, The thickness of the second transparent electron-conducting layer is 5 nm to 20 nm.

11. The solar cell according to any one of claims 1 to 10, characterized in that, The electron mobility of the first transparent conductive electron layer is 35 cm 2 / V·s to 50 cm 2 / V·s, and the resistivity is 4×10 -4 ohm·cm to 3×10 -3 ohm·cm.

12. The solar cell according to any one of claims 1 to 11, characterized in that, The mobility of the second transparent electron-conducting layer is 80 cm 2 / V·s to 150 cm 2 / V·s, and the resistivity is less than 4×10 -4 ohm·cm.

13. The solar cell according to claim 12, characterized in that, The contact resistance between the second transparent electron-conducting layer and the first metal electrode is less than 0.5 ohm.

14. The solar cell according to claim 12, characterized in that, The mobility of the second transparent conductive electron layer is 120 cm 2 / V·s to 150 cm 2 / V·s, and the resistivity is less than 2.5×10 -4 ohm·cm.

15. The solar cell according to any one of claims 1 to 14, characterized in that, The perovskite solar cell is a perovskite tandem solar cell. The perovskite tandem solar cell includes a silicon substrate cell and a composite layer, a first transport layer, a perovskite layer, a second transport layer, and a buffer layer stacked in sequence on the silicon substrate cell. The first transparent electron-conducting layer and the second transparent electron-conducting layer are stacked in sequence on the buffer layer. One of the first transport layer and the second transport layer is an electron transport layer, and the other is a hole transport layer. It further includes a second metal electrode, and the second metal electrode forms an ohmic contact with the silicon substrate cell.

16. The solar cell according to any one of claims 1 to 14, characterized in that, The perovskite solar cell is a single-junction perovskite solar cell. The single-junction perovskite solar cell further includes a transparent conductive substrate and a first transport layer, a perovskite layer, a second transport layer, and a buffer layer stacked in sequence on the transparent conductive substrate. The first transparent electron-conducting layer and the second transparent electron-conducting layer are stacked in sequence on the buffer layer. One of the first transport layer and the second transport layer is an electron transport layer, and the other is a hole transport layer. It further includes a second metal electrode, and the second metal electrode forms an ohmic contact with the silicon substrate cell.

17. A method for preparing a solar cell, characterized in that, The method for preparing the solar cell according to any one of claims 1-16 includes the following steps: Preparing a transparent conductive layer: preparing a first transparent electron-conducting layer, and preparing a second transparent electron-conducting layer on the first transparent electron-conducting layer; Fabricating the first metal electrode: Fabricate the first metal electrode on the second transparent conductive electron layer to form an ohmic contact between the second transparent conductive electron layer and the first metal electrode.

18. The method for preparing a solar cell according to claim 17, wherein, The first transparent conductive electron layer is fabricated by magnetron sputtering. The sputtering pressure is 0.3 Pa to 0.8 Pa, the temperature is 20 °C to 100 °C, the flow rate of argon gas introduced is 200 Sccm to 900 Sccm, the ratio of the oxygen flow rate to the argon flow rate is 1.5% to 6%, and the power density is 0.5 kW / m to 6 kW / m.

19. The manufacturing method of the solar cell according to claim 18, characterized in that, The second transparent conductive electron layer is fabricated by magnetron sputtering or plasma deposition process. When the second transparent conductive electron layer is fabricated by plasma deposition process, the plasma deposition pressure is 0.3 Pa to 0.8 Pa, the temperature is 20 °C to 100 °C, the flow rate of the argon gas introduced is 50 Sccm to 200 Sccm, the ratio of the oxygen flow rate to the argon flow rate is 5% to 25%, the current is 100 A to 170 A, and the top target speed is 0.3 mm / s to 0.5 mm / s.

20. The manufacturing method of the solar cell according to claim 19, characterized in that, During the fabrication process of the second transparent conductive electron layer, water vapor and hydrogen are also introduced. The water vapor flow rate is 1 Sccm to 5 Sccm, and the hydrogen accounts for 0.5% to 2.8% of the sum of the argon and oxygen flow rates.

21. The manufacturing method of the solar cell according to any one of claims 17 to 20, characterized in that, The perovskite solar cell is a perovskite tandem solar cell. The fabrication method of the perovskite tandem solar cell includes the following steps: Providing a silicon substrate cell; Fabricating a composite layer on the silicon substrate cell; Fabricating a first transport layer on the composite layer; Fabricating a perovskite layer on the first transport layer; Fabricating a second transport layer on the perovskite layer; Fabricating a buffer layer on the second transport layer; Fabricating the transparent conductive layer on the buffer layer; Fabricating a second metal electrode on the silicon substrate cell; One of the first transport layer and the second transport layer is an electron transport layer, and the other is a hole transport layer.

22. The manufacturing method of the solar cell according to any one of claims 17 to 20, characterized in that, The perovskite solar cell is a single-junction perovskite solar cell. The fabrication method of the single-junction perovskite solar cell includes the following steps: Providing a transparent conductive substrate; Fabricating a first transport layer on the transparent conductive substrate; Fabricating a perovskite layer on the first transport layer; Fabricating a second transport layer on the perovskite layer; Fabricating a buffer layer on the second transport layer; Fabricating a second metal electrode on the transparent conductive substrate; One of the first transport layer and the second transport layer is an electron transport layer, and the other is a hole transport layer.

23. A photovoltaic module, characterized in that, The photovoltaic module includes the solar cell as claimed in any one of claims 1 - 16 or the solar cell fabricated by the fabrication method as claimed in any one of claims 17 - 22.

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