Solar cell

Abstract

The utility model discloses a solar cell. The solar cell comprises a substrate, a front intrinsic silicon-containing film layer, a first doped silicon-containing film layer and a light conversion conductive structure, the front intrinsic silicon-containing film layer, the first doped silicon-containing film layer and the light conversion conductive structure are stacked on a first main surface of the substrate from inside to outside, the light conversion conductive structure comprises a first transparent conductive film layer, an ultraviolet light conversion layer, a conductive channel and a second transparent conductive film layer, the ultraviolet light conversion layer is located between the first transparent conductive film layer and the second transparent conductive film layer and used for converting ultraviolet light into visible light; the conductive channel is embedded in the ultraviolet light conversion layer and used for conducting the first transparent conductive film layer and the second transparent conductive film layer. According to the scheme, the stability of the solar cell is effectively improved.

Description

Technical Field

[0001] The utility model relates to a solar cell. Background Art

[0002] How to improve the efficiency of solar cells is still one of the key points of research and breakthroughs in the field of solar cells. Current research has found that when sunlight irradiates solar cells, the ultraviolet rays in the sunlight will damage the amorphous silicon film layer in the heterojunction solar cells. After the amorphous silicon film layer is damaged, the efficiency of the heterojunction solar cells will be attenuated. Therefore, how to prevent ultraviolet rays from damaging the amorphous silicon film layer has become one of the ways to improve the efficiency of solar cells.

[0003] At present, the main method is to cover the surface of solar cells with UV (Ultra-Violet Ray) light transfer film to block ultraviolet light. However, the UV light transfer film will also cover the surface of the metal electrode. When the solar cell is used to produce photovoltaic modules, the presence of the UV light transfer film will cause the metal electrode and the welding ribbon to have insufficient tension, resulting in poor reliability of the photovoltaic modules produced by the solar cell. Utility Model Content

[0004] In view of this, the utility model provides a solar cell and a preparation method thereof. The solar cell converts ultraviolet light into visible light by means of an ultraviolet light conversion layer, thereby improving the light utilization rate of the solar cell. At the same time, by setting the ultraviolet light conversion layer between a first transparent conductive film layer and a second transparent conductive film layer, the influence of directly setting the ultraviolet light conversion layer on the surface of the finished battery on the subsequent soldering reliability of the soldering ribbon is avoided, thereby effectively improving the reliability of the soldering between the solar cell and the soldering ribbon.

[0005] In order to solve the above technical problems, the utility model provides the following technical solutions:

[0006] In a first aspect, the utility model provides a solar cell, characterized in that it comprises: a substrate, a front intrinsic silicon-containing film layer, a first doped silicon-containing film layer and a light conversion conductive structure stacked from inside to outside on a first main surface of the substrate, wherein:

[0007] The light conversion conductive structure comprises: a first transparent conductive film layer, an ultraviolet light conversion layer, a conductive channel and a second transparent conductive film layer, wherein:

[0008] The ultraviolet light conversion layer is located between the first transparent conductive film layer and the second transparent conductive film layer, and is used to convert ultraviolet light into visible light;

[0009] The conductive channel is embedded in the ultraviolet light conversion layer and is used for conducting the first transparent conductive film layer and the second transparent conductive film layer.

[0010] The technical solution of the first aspect of the above utility model has the following advantages or beneficial effects:

[0011] The solar cell provided by the embodiment of the utility model converts ultraviolet light into visible light that can be used by the solar cell by means of the ultraviolet light conversion layer, thereby improving the light utilization rate of the solar cell. At the same time, by setting the ultraviolet light conversion layer between the first transparent conductive film layer and the second transparent conductive film layer, it is avoided that the ultraviolet light conversion layer is directly set on the surface of the finished cell to affect the reliability of the welding of the welding strip in the subsequent process of making the solar cell string. Therefore, the solar cell provided by the embodiment of the utility model can still ensure the reliability of the subsequent welding strip connection of the solar cell while adding the ultraviolet light conversion layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic diagram of a first cross-sectional structure of a solar cell according to an embodiment of the utility model;

[0013] Figure 2 is a schematic diagram of a second cross-sectional structure of a solar cell according to an embodiment of the utility model;

[0014] Figure 3 is a schematic diagram of a third cross-sectional structure of a solar cell according to an embodiment of the utility model;

[0015] Figure 4 It is a structural schematic diagram of the relative relationship between the ultraviolet light conversion layer and the conductive channel in the solar cell according to the embodiment of the utility model.

[0016] The reference numerals are as follows:

[0017] 10-substrate; 20-front intrinsic silicon-containing film layer; 30-first doped silicon-containing film layer; 40-light-converting conductive structure; 41-first transparent conductive film layer; 42-ultraviolet light conversion layer; 43-conductive channel; 44-second transparent conductive film layer; 50-front metal electrode; 60-back intrinsic silicon-containing film layer; 70-second doped silicon-containing film layer; 80-third transparent conductive film layer; 90-back metal electrode. DETAILED DESCRIPTION

[0018] The embodiments of the present invention generally refer to a structure from inside to outside, from a position close to the structure to a position far away from the structure.

[0019] The stacking arrangement involved in the embodiments of the present invention generally refers to a structure stacked on top of or below another structure, and the structure may be in direct or indirect contact with the main surface of the other structure. Direct contact generally refers to the one structure being directly formed, grown, or deposited on the upper or lower surface of the other structure; indirect contact generally refers to the other functional layers being formed between the one structure and the other structure.

[0020] The upper surface or front surface of a structure involved in the embodiments of the utility model generally refers to a main surface of the structure facing the sunlight or upward during the use of the solar cell; the lower surface or back surface of a structure generally refers to a main surface of the structure facing away from the sunlight or downward during the use of the solar cell. Among them, the upper surface and the lower surface or the front and the back surface of a structure are opposite to each other.

[0021] The "first" and "second" etc. involved in the embodiments of the present invention are used to distinguish different structures or components or different positions of the same structure, and are not intended to limit the number, order, etc. of structures or components. For example, the first transparent conductive film layer and the second transparent conductive film layer involved in the embodiments of the present invention are generally used to distinguish two transparent conductive film layers at different positions and with a certain difference in thickness.

[0022] In the prior art, although there is also a UV light conversion layer set on the surface of the solar cell. However, in the prior art, the UV light conversion layer is mainly set on the front surface of the solar cell, and the UV light conversion layer is either set in the area not covered by the front metal electrode or covers the front metal electrode. In the case where the UV light conversion layer is set in the area not covered by the front metal electrode, it is necessary to introduce a template or the like to cover the front metal electrode. The template is combined with scraping or spin coating to prepare the UV light conversion layer in the area not covered by the front metal electrode. The process is relatively complicated. In the case where a whole layer of UV light conversion layer is set on the front surface of the entire solar cell (that is, the UV light conversion layer will cover the front metal electrode), on the one hand, since the UV light conversion layer has a relatively poor conductivity or even no conductivity, it will hinder the conduction of the front metal electrode, resulting in a reduction in the conduction performance of the solar cell; on the other hand, the electrical connection between the front metal electrode and the soldering strip has a relatively poor welding ability between the UV light conversion layer and the soldering strip, which will affect the soldering stability of the soldering strip, thereby affecting the reliability of the photovoltaic module made of the solar cell.

[0023] At present, it is urgent to solve the above-mentioned problems of solar cells having the capability of converting ultraviolet light into visible light by improving the structural design of the solar cells having the capability of converting ultraviolet light into visible light.

[0024] in, Figures 1 to 3A schematic cross-sectional structure diagram showing a partial structure of a solar cell provided by an embodiment of the utility model; Figure 4 A schematic structural diagram showing the relative relationship between the ultraviolet light conversion layer and the conductive channel provided in an embodiment of the utility model is shown.

[0025] like Figure 1 , Figure 2 and Figure 3 As shown, the embodiment of the utility model provides a solar cell. The solar cell may include:

[0026] A substrate 10, a front intrinsic silicon-containing film layer 20, a first doped silicon-containing film layer 30 and a light conversion conductive structure 40 are stacked from inside to outside on a first main surface of the substrate 10, wherein:

[0027] The light conversion conductive structure 40 includes: a first transparent conductive film layer 41, an ultraviolet light conversion layer 42, a conductive channel 43 and a second transparent conductive film layer 44, wherein:

[0028] The ultraviolet light conversion layer 42 is located between the first transparent conductive film layer 41 and the second transparent conductive film layer 44 and is used to convert ultraviolet light into visible light;

[0029] The conductive channel 43 is embedded in the ultraviolet light conversion layer 42 and is used to conduct the first transparent conductive film layer 41 and the second transparent conductive film layer 44 .

[0030] In the solar cell provided in the embodiment of the utility model, the substrate 10 may be an N-type conductive silicon substrate or a P-type conductive silicon substrate. Preferably, the substrate 10 is an N-type conductive silicon substrate.

[0031] The surface of the substrate 10 may be Figure 1 The structure shown is a plane structure, it can also be Figure 2 The single-sided suede structure shown can also be Figure 3 In a preferred embodiment, the surface of the substrate 10 is Figure 2 The single-sided suede structure shown or Figure 3 Double suede construction shown.

[0032] The surface of the substrate 10 is Figure 2 The single suede structure shown or Figure 3 The double velvet structure shown is based on the various film layers formed on the surface of the substrate 10, such as the front intrinsic silicon-containing film layer 20, the first doped silicon-containing film layer 30, the first transparent conductive film layer 41, the ultraviolet light conversion layer 42, the conductive channel 43 and the second transparent conductive film layer 44, which are also formed along the velvet structure.

[0033] The front intrinsic silicon-containing film layer 20 is a single layer or a stacked layer formed by any one or more of the following materials: microcrystalline silicon, nano silicon, amorphous silicon, silicon oxide and silicon carbide; wherein the microcrystalline silicon film layer generally refers to a film layer formed by a mixture of crystalline silicon and amorphous silicon. The nano silicon film layer generally refers to a film layer formed by nano-sized crystalline silicon. The front intrinsic silicon-containing film layer 20 mainly plays the role of tunneling passivation in the solar cell to increase carrier transport.

[0034] Among them, the front intrinsic silicon-containing film layer 20 is a single-layer or stacked film layer formed by any one or more materials of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide. Specifically, it means that the front intrinsic silicon-containing film layer 20 can be a single-layer film layer formed by any one of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide. For example, the single-layer film layer of the front intrinsic silicon-containing film layer 20 is a single-layer film layer formed by nano-silicon. For another example, the single-layer film layer of the front intrinsic silicon-containing film layer 20 is a single-layer film layer formed by silicon oxide.

[0035] In addition, the front intrinsic silicon-containing film layer 20 can also be a stacked film layer formed by any one of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide (the stacked film layer is formed by stacking multiple film layers formed by the same material). For example, the stacked film layer of the front intrinsic silicon-containing film layer 20 is formed by stacking multiple film layers formed by microcrystalline silicon. For another example, the stacked film layer of the front intrinsic silicon-containing film layer 20 is formed by stacking multiple film layers formed by amorphous silicon.

[0036] In addition, the front intrinsic silicon-containing film layer 20 can also be a single-layer film layer or a stacked film layer formed of any of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide. For a single-layer film layer formed of any of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide, it means that the single-layer film layer contains a mixture of any of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide. For a stacked film layer formed of any of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide, it means that each film layer in the stacked film layer can be any one or a mixture of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide. For a stacked film layer formed of any of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide, and each film layer in the stacked film layer is formed of any of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide, there are at least two film layers in the stacked film layer that use different materials. In addition, for the stacked film layers formed by any multiple of microcrystalline silicon, nanosilicon, amorphous silicon, silicon oxide and silicon carbide, any one layer or multiple layers in the stacked film layers can be formed by any one of microcrystalline silicon, nanosilicon, amorphous silicon, silicon oxide and silicon carbide, and the remaining film layers in the stacked film layers are a mixture of any multiple of microcrystalline silicon, nanosilicon, amorphous silicon, silicon oxide and silicon carbide.

[0037] The thickness of the front intrinsic silicon-containing film layer 20 may be 1-50 nm. For example, the thickness of the front intrinsic silicon-containing film layer 20 may be 1 nm, 5 nm, 8 nm, 10 nm, 15 nm, 18 nm, 20 nm, 25 nm, 30 nm, 33 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc.

[0038] The first doped silicon-containing film layer 30 is a single layer or a stacked layer formed by any one or more of the following materials and doped with an activated first doping element: microcrystalline silicon, nano silicon, amorphous silicon, silicon oxide, and silicon carbide.

[0039] The first doped silicon-containing film layer 30 is a single layer or a stacked layer of any one or more materials formed of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide, which means that the first doped silicon-containing film layer 30 can be a single layer formed of any one of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide, or a single layer formed of any one of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide (that is, a mixture of any one of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide in a single layer), or a stacked layer formed of any one of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide ( That is, each film layer in the stacked film layers is formed of the same material), or it can be a stacked film layer formed of any multiple of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide (that is, each film layer in the stacked film layers can be a mixture of any multiple of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide, or each film layer in the stacked film layers is formed of one material and at least two film layers use different materials; it can also be that one or more layers in the stacked film layers are formed of one material, and each layer in the remaining film layers is formed of a mixture of any multiple of microcrystalline silicon, nano-silicon, amorphous silicon, silicon oxide and silicon carbide).

[0040] It can be understood that the specific implementation of doping the activated first doping element in the film layer is generally to first dope the first doping element into the film layer and then activate the first doping element by annealing.

[0041] The thickness of the first doped silicon-containing film 30 may be 1-50 nm. For example, the thickness of the first doped silicon-containing film 30 may be 1 nm, 2 nm, 5 nm, 8 nm, 10 nm, 15 nm, 18 nm, 20 nm, 25 nm, 28 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc.

[0042] Furthermore, the conductivity type of the doping element contained in the first doped silicon-containing film layer 30 is consistent with the conductivity type of the substrate 10. For example, when the substrate 10 is an N-type conductive silicon substrate, the conductivity type of the doping element is also N-type, such as the N-type conductive doping element can be phosphorus; when the substrate 10 is a P-type conductive silicon substrate, the conductivity type of the doping element is also P-type, such as the P-type conductive doping element can be boron, aluminum, etc.

[0043] It is worth noting that the front intrinsic silicon-containing film layer 20 and the first doped silicon-containing film layer 30 can be prepared by existing technical means, such as physical vapor deposition, chemical vapor deposition, plasma vapor deposition, magnetron sputtering, etc.

[0044] Since ultraviolet light irradiation can destroy silicon-hydrogen bonds, the passivation layer of the solar cell is destroyed, thereby causing the performance of the solar cell to decay. By setting a UV light conversion layer above the front intrinsic silicon-containing film layer 20 and the first doped silicon-containing film layer 30, the amount of ultraviolet light reaching the front intrinsic silicon-containing film layer 20 and the first doped silicon-containing film layer 30 can be effectively reduced, and even ultraviolet light can be prevented from reaching the front intrinsic silicon-containing film layer 20 and the first doped silicon-containing film layer 30, so as to prevent ultraviolet light in sunlight from destroying the passivation of the solar cell.

[0045] Furthermore, the ultraviolet light is converted into visible light that can be used by the solar cell by the ultraviolet light conversion layer, thereby improving the light utilization rate of the solar cell. At the same time, by setting the ultraviolet light conversion layer between the first transparent conductive film layer and the second transparent conductive film layer, the ultraviolet light conversion layer is prevented from affecting the reliability of the welding ribbon in the subsequent solar cell string manufacturing process. Therefore, the solar cell provided by the embodiment of the utility model can still ensure the reliability of the subsequent welding ribbon connection of the solar cell while adding the ultraviolet light conversion layer.

[0046] In addition, the ultraviolet light conversion layer is arranged between the first transparent conductive film layer and the second transparent conductive film layer, which can block ultraviolet light from reaching the silicon-containing film layer (the front intrinsic silicon-containing film layer and the first doped silicon-containing film layer), thereby avoiding ultraviolet light from damaging the silicon-containing film layer and reducing the risk of performance degradation of the silicon-containing film layer and the solar cell, thereby effectively improving the cell efficiency of the solar cell and the service life of the solar cell.

[0047] In addition, the ultraviolet light conversion layer is arranged between the first transparent conductive film layer and the second transparent conductive film layer. There is no need to introduce a mask in the process of preparing the ultraviolet light conversion layer. The ultraviolet light conversion layer can be prepared by adding a spraying or scraping step to the existing solar cell manufacturing process. The process used is simple and can effectively control the production cost of solar cells.

[0048] Furthermore, compared with the existing UV light conversion layer which is made of expensive organic materials, resulting in increased production costs of solar cells and being unfavorable for marketization, the ultraviolet light conversion layer 42 in the solar cell of the embodiment of the utility model is composed of quantum dots, which generally refer to small crystals of nanometer size.

[0049] Specifically, the ultraviolet light conversion layer 42 in the solar cell of the embodiment of the utility model may include any one or more of the following quantum dots: carbon quantum dots, silicon quantum dots and germanium quantum dots. Compared with the existing UV conversion layer made of relatively expensive organic materials, the embodiment of the utility model selects any one or more of carbon quantum dots, silicon quantum dots and germanium quantum dots to form the ultraviolet light conversion layer 42. Unlike the characteristics of organic materials such as easy volatility, poor stability and easy changeability of organic components, the quantum dots are relatively stable and not easy to change. In addition to providing a new structure of the ultraviolet light conversion layer 42, it can also effectively improve the stability and service life of the ultraviolet light conversion layer 42.

[0050] Among them, the size of the quantum dots included in the ultraviolet light conversion layer 42 in the embodiment of the utility model is generally 1 to 30nm. For example, the size of the quantum dots included in the ultraviolet light conversion layer 42 can be 1nm, 2nm, 5nm, 8nm, 10nm, 13nm, 15nm, 18nm, 20nm, 23nm, 25nm, 27nm, 28nm, 30nm, etc. By controlling the size of the quantum dots to 1 to 30nm, it can be ensured that the ultraviolet light conversion layer 42 converts ultraviolet light into visible light, and the influence of the ultraviolet light conversion layer 42 on visible light can be reduced, so as to effectively improve the light utilization rate of the solar cell. In a preferred embodiment, the size of the quantum dots included in the ultraviolet light conversion layer 42 can be 1 to 15nm. For example, the size of the quantum dots included in the ultraviolet light conversion layer 42 can be 1nm, 2nm, 4nm, 5nm, 6nm, 8nm, 9nm, 10nm, 12nm, 13nm, 14nm, 15nm, etc. To further improve the light utilization rate of solar cells.

[0051] Furthermore, if Figure 4 As shown, the conductive channel 43 in the solar cell provided by the embodiment of the utility model is composed of the area of ​​the ultraviolet light conversion layer 42 that is not occupied by quantum dots.

[0052] Specifically, by mixing the above-mentioned quantum dots into a solution, the solution mixed with quantum dots is applied to the surface of the first transparent conductive film layer 41 by spin coating, spray coating, or scraping coating, and the solution (the solution is generally an organic solvent that is easily volatile and does not damage the transparent conductive film layer) is dried to evaporate, leaving quantum dots on the surface of the first transparent conductive film layer 41 to form an ultraviolet light conversion layer 42, that is, the ultraviolet light conversion layer 42 is only composed of quantum dots, and its organic solvent has been completely evaporated. The organic solvent can be any organic solvent that is easily volatile and does not damage the transparent conductive film layer. Among them, drying can be carried out at room temperature, or the substrate coated with the above-mentioned solution can be placed in a heating environment to volatilize the organic solvent in the solution, wherein the temperature of the heating environment can meet the volatilization of the organic solvent. In addition, after the organic solvent evaporates, the area not covered by the quantum dots forms a conductive channel 43.

[0053] Understandably, Figure 4 A portion of the conductive channel 43 on the ultraviolet light conversion layer 42 is shown only as an example, which does not constitute a limitation on the size and position of the conductive channel 43 .

[0054] The amount of quantum dots mixed into the solution can be regulated according to demand.

[0055] Furthermore, the embodiment of the utility model can ensure the conversion of ultraviolet light while ensuring the permeability of visible light to the underlying film layer by controlling the thickness of the ultraviolet light conversion layer 42 in the range of 1 to 20 nm, so as to effectively improve the light utilization rate of the solar cell. For example, the thickness of the ultraviolet light conversion layer 42 can be 1 nm, 2 nm, 4 nm, 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 17 nm, 18 nm, 20 nm, etc. In a preferred embodiment, the thickness of the ultraviolet light conversion layer 42 can be 1 to 15 nm. For example, the thickness of the ultraviolet light conversion layer 42 can be 1 nm, 2 nm, 4 nm, 5 nm, 7 nm, 8 nm, 10 nm, 12 nm, 13 nm, 15 nm, etc., so as to achieve a better effect of the light utilization rate of the solar cell.

[0056] Furthermore, in the solar cell structure provided by the embodiment of the utility model, the first transparent conductive film layer 41 is located between the first doped silicon-containing film layer 30 and the ultraviolet light conversion layer 42; the thickness of the first transparent conductive film layer 41 is greater than the thickness of the second transparent conductive film layer 44. By adjusting the thickness of the first transparent conductive film layer 41 to be greater than the thickness of the second transparent conductive film layer 44, it is ensured that the second transparent conductive film layer 44 covers the ultraviolet light conversion layer 42, so as to avoid the ultraviolet light conversion layer 42 affecting the subsequent solar cell and the welding ribbon welding connection, and reduce the reflection of the second transparent conductive film layer 44 on the ultraviolet light, so as to increase the second transparent conductive film layer 44 to transmit the ultraviolet light, so as to increase the light utilization rate of the solar cell.

[0057] The sum of the thicknesses of the first transparent conductive film layer 41 and the second transparent conductive film layer 44 is 1 to 100 nm. For example, the sum of the thicknesses of the first transparent conductive film layer 41 and the second transparent conductive film layer 44 may be 1 nm, 4 nm, 5 nm, 8 nm, 10 nm, 15 nm, 20 nm, 24 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, etc. In a preferred embodiment, the sum of the thicknesses of the first transparent conductive film layer 41 and the second transparent conductive film layer 44 is 60 to 80 nm. For example, the sum of the thicknesses of the first transparent conductive film layer 41 and the second transparent conductive film layer 44 may be 60 nm, 62 nm, 65 nm, 66 nm, 68 nm, 70 nm, 73 nm, 75 nm, 78 nm, 80 nm, etc.

[0058] It is worth noting that in the actual production process, the thickness of the second transparent conductive film layer 44 can be matched with the refractive index of the second transparent conductive film layer 44 to reduce the ultraviolet light reflection. That is, according to the refractive index of the second transparent conductive film layer 44, the thickness of the second transparent conductive film layer 44 is adjusted to achieve the purpose of reducing the ultraviolet light reflection. Among them, the refractive index of the second transparent conductive film layer 44 is generally related to the target material used to prepare the second transparent conductive film layer 44 and the preparation process.

[0059] The first transparent conductive film layer 41 and the second transparent conductive film layer 44 may be made of the same material. Specifically, the first transparent conductive film layer 41 and the second transparent conductive film layer 44 may include: a single transparent film layer or a stacked transparent film layer formed of metal oxide and / or metal nitride and a third doping element doped in the single transparent film layer or the stacked transparent film layer, wherein:

[0060] The metal oxide and / or metal nitride is any one or more combinations of the following materials:

[0061] Indium oxide, tin oxide, zinc oxide, cadmium oxide and titanium nitride;

[0062] The doping element doped in the single-layer transparent film layer or the stacked transparent film layer is any one or more of the following elements:

[0063] Indium, tin, calcium, aluminum, cadmium, zinc, cerium and fluorine.

[0064] Specifically, the single-layer transparent film layer formed by metal oxides and / or metal nitrides means that the single-layer transparent film layer may contain only any one of indium oxide, tin oxide, zinc oxide, cadmium oxide and titanium nitride, or may contain a mixture of any multiple of indium oxide, tin oxide, zinc oxide, cadmium oxide and titanium nitride.

[0065] Furthermore, for the stacked transparent film layers formed of metal oxides and / or metal nitrides, it means that each layer in the stacked transparent film layers may contain only any one of indium oxide, tin oxide, zinc oxide, cadmium oxide and titanium nitride (wherein the metal oxides and / or metal nitrides included in each layer in the stacked transparent film layers may be the same or different), and each layer in the stacked transparent film layers may also contain a mixture of any multiple of indium oxide, tin oxide, zinc oxide, cadmium oxide and titanium nitride (wherein the mixture of multiple materials included in each layer in the stacked transparent film layers may be the same or different).

[0066] Furthermore, the first transparent conductive film layer 41 and the second transparent conductive film layer 44 are doped with hydrogen elements. By doping the first transparent conductive film layer 41 and the second transparent conductive film layer 44 with hydrogen elements, the carrier mobility of the solar cell can be effectively improved.

[0067] Furthermore, if Figure 1 and Figure 2 As shown, the solar cell provided in the above embodiment may further include: a front metal electrode 50, wherein:

[0068] The front metal electrode 50 is disposed on the second transparent conductive film layer 44 and is electrically connected to the second transparent conductive film layer 44. A photovoltaic module is prepared by connecting the front metal electrode 50 with the welding strip to realize current transmission and collection.

[0069] The front metal electrode 50 is any one of the following electrodes or a laminated electrode formed by the following multiple electrodes:

[0070] Silver electrodes, copper electrodes, silver alloy electrodes, copper alloy electrodes, and multilayer electrodes formed of nickel, copper and silver.

[0071] In addition, other functional film layers such as an anti-reflection layer may be disposed on the second transparent conductive film layer 44 of the solar cell or below the second transparent conductive film layer 44 .

[0072] Although the embodiments of the present invention provide Figure 1 and Figure 2 The structure of a heterojunction solar cell is only given as an example, but the structure provided in the above embodiment of the utility model can be applied to other types of solar cells, such as back contact solar cells, perovskite solar cells, perovskite stacked solar cells, etc., because the ultraviolet spectrum response of these cells is worse than that of the visible light region, and converting ultraviolet light into visible light can also improve the efficiency of the cell. In a preferred embodiment, the solar cell provided in the embodiment of the utility model is a heterojunction solar cell.

[0073] Furthermore, if Figure 1and Figure 2 As shown, the solar cell may further include: a back intrinsic silicon-containing film layer 60 , a second doped silicon-containing film layer 70 , a third transparent conductive film layer 80 and a back metal electrode 90 stacked from inside to outside on the second main surface of the substrate 10 .

[0074] The conductivity type of the doping element included in the second doped silicon-containing film layer 70 is opposite to the conductivity type of the substrate 10. For example, when the substrate 10 is an N-type conductive silicon substrate, the conductivity type of the doping element included in the second doped silicon-containing film layer 70 is P-type, such as boron, aluminum, etc.; when the substrate 10 is a P-type conductive silicon substrate, the conductivity type of the doping element included in the second doped silicon-containing film layer 70 can be N-type, such as phosphorus, etc.

[0075] The back intrinsic silicon-containing film layer 60 may be a single layer or a stacked layer formed of any one or more of the following materials: microcrystalline silicon, nano silicon, amorphous silicon, silicon oxide, and silicon carbide.

[0076] Specifically, the back intrinsic silicon-containing film layer 60 is a single-layer film layer formed of any one of microcrystalline silicon, nano silicon, amorphous silicon, silicon oxide and silicon carbide, which means that the back intrinsic silicon-containing film layer 60 is a single-layer film layer formed of one material.

[0077] The back intrinsic silicon-containing film layer 60 is a stacked film layer formed by any one of microcrystalline silicon, nano silicon, amorphous silicon, silicon oxide and silicon carbide, which means that the back intrinsic silicon-containing film layer 60 is formed by stacking multiple film layers, wherein each film layer is formed by the same material.

[0078] The back intrinsic silicon-containing film layer 60 is a stacked film layer formed by any of microcrystalline silicon, nano silicon, amorphous silicon, silicon oxide and silicon carbide. It means that the back intrinsic silicon-containing film layer 60 is formed by the superposition of multiple film layers, each layer in the stacked film layer can be formed by one material and there are at least two film layers containing different materials; each layer in the stacked film layer can also be formed by a mixture of multiple materials.

[0079] In addition, the thickness of the back intrinsic silicon-containing film layer 60 can be 1 to 50 nm; for example, the thickness of the back intrinsic silicon-containing film layer 60 can be 1 nm, 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 23 nm, 25 nm, 27 nm, 30 nm, 33 nm, 35 nm, 38 nm, 40 nm, 45 nm, 48 nm, 50 nm, etc.

[0080] The second doped silicon-containing film layer 70 is a single layer or a stacked layer formed of any one or more of the following materials doped with an activated second doping element: microcrystalline silicon, nano silicon, amorphous silicon, silicon oxide, and silicon carbide. It can be understood that the specific implementation of doping the activated second doping element in the film layer is generally to first dope the second doping element into the film layer and activate the second doping element by annealing.

[0081] Among them, the single-layer film layer or the stacked film layer of the second doped silicon-containing film layer 70 can be as described above. For the single-layer film layer, it can be a single material or a mixture of multiple materials; for the stacked film layer, the film layers it includes can be formed of the same material, or each film layer can be formed of different materials, wherein, for each film layer to be formed of different materials, it can be that each film layer is formed of a single material and the materials of at least two film layers are different; for each film layer to be formed of different materials, it can be that each film layer is a mixture of multiple materials, and the materials between each film layer can be completely the same, partially the same, or completely different.

[0082] Further, the thickness of the second doped silicon-containing film layer 70 may be 1-50 nm. For example, the thickness of the second doped silicon-containing film 70 may be 1 nm, 2 nm, 5 nm, 8 nm, 10 nm, 15 nm, 18 nm, 20 nm, 25 nm, 28 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc.

[0083] The third transparent conductive film layer 80 may include: a single transparent film layer or a stacked transparent film layer formed of metal oxide and / or metal nitride and a third doping element doped in the single transparent film layer or the stacked transparent film layer, wherein:

[0084] The metal oxide and / or metal nitride is any one or more combinations of the following materials:

[0085] Indium oxide, tin oxide, zinc oxide, cadmium oxide and titanium nitride;

[0086] The third doping element is any one or more of the following elements:

[0087] Indium, tin, calcium, aluminum, cadmium, zinc, cerium and fluorine.

[0088] Among them, for the single-layer transparent film layer or the stacked transparent film layer formed by metal oxide and / or metal nitride, such as the first transparent conductive film layer 41 or the second transparent conductive film layer 44, the single-layer transparent film layer and the stacked transparent film layer are not described in detail here.

[0089] Among them, the thickness of the third transparent conductive film layer 80 can be 1 to 100 nm; for example, the thickness of the third transparent conductive film layer 80 can be 1 nm, 4 nm, 5 nm, 8 nm, 10 nm, 15 nm, 20 nm, 24 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, etc.

[0090] Furthermore, the back metal electrode 90 may be any one of the following electrodes or a laminated electrode formed by the following multiple electrodes:

[0091] Silver electrodes, copper electrodes, silver alloy electrodes, copper alloy electrodes, and multilayer electrodes formed of nickel, copper and silver.

[0092] Furthermore, for the solar cell of any of the above embodiments, the present utility model embodiment provides a method for preparing the solar cell. Specifically, the method for preparing the solar cell may include the following steps:

[0093] On the first main surface of the substrate 10, a front intrinsic silicon-containing film layer 20, a first doped silicon-containing film layer 30, a first transparent conductive film layer 41, an ultraviolet light conversion layer 42 and a second transparent conductive film layer 44 are sequentially stacked, wherein:

[0094] The ultraviolet light conversion layer 42 is prepared by spin coating, spray coating or blade coating;

[0095] During the formation of the ultraviolet light conversion layer 42 , a conductive channel 43 for conducting the first transparent conductive film layer 41 and the second transparent conductive film layer 44 is simultaneously formed in the ultraviolet light conversion layer 42 .

[0096] Among them, the above-mentioned preparation of the front intrinsic silicon-containing film layer 20, the first doped silicon-containing film layer 30, the first transparent conductive film layer 41 and the second transparent conductive film layer 44 can be prepared by existing preparation processes such as physical vapor deposition, chemical vapor deposition, plasma vapor deposition, magnetron sputtering and other processes.

[0097] The specific implementation method of preparing the ultraviolet light conversion layer 42 by spin coating, spray coating or scraping coating may include: mixing quantum dots into a solution (the solution is generally an organic solvent that does not affect the first transparent conductive film layer 41), spin coating, spray coating or scraping the solution mixed with quantum dots onto the surface of the first transparent conductive film layer 41, and removing the organic components in the solution by drying (the drying can be room temperature drying or heating drying, wherein the heating temperature of heating drying is generally related to the volatilization temperature and boiling point of the organic solvent, for example, the heating temperature can be controlled near the boiling point of the organic solvent), and the quantum dots are distributed in the first transparent conductive film layer 41 in an aggregated manner, and the area not covered by the quantum dots becomes a conductive channel 43 for conducting the first transparent conductive film layer 41 and the second transparent conductive film layer 44. The quantum dots generally refer to nano-sized grains.

[0098] The quantum dots may be any one or more of carbon quantum dots, silicon quantum dots and germanium quantum dots.

[0099] Among them, the size of the quantum dots included in the prepared ultraviolet light conversion layer 42 can generally be controlled to be 1 to 30 nm. For example, the size of the quantum dots included in the ultraviolet light conversion layer 42 can be 1 nm, 2 nm, 5 nm, 8 nm, 10 nm, 13 nm, 15 nm, 18 nm, 20 nm, 23 nm, 25 nm, 27 nm, 28 nm, 30 nm, etc. By controlling the size of the quantum dots to be 1 to 30 nm, it is possible to ensure that the ultraviolet light conversion layer 42 converts ultraviolet light into visible light, and can reduce the influence of the ultraviolet light conversion layer 42 on visible light, so as to effectively improve the light utilization rate of the solar cell. In a preferred embodiment, the size of the quantum dots included in the ultraviolet light conversion layer 42 can be 1 to 15 nm. For example, the size of the quantum dots included in the ultraviolet light conversion layer 42 can be 1 nm, 2 nm, 4 nm, 5 nm, 6 nm, 8 nm, 9 nm, 10 nm, 12 nm, 13 nm, 14 nm, 15 nm, etc. By controlling the size of the quantum dots included in the ultraviolet light conversion layer 42, it is possible to ensure that ultraviolet light is converted into visible light.

[0100] Furthermore, in the process of preparing the ultraviolet light conversion layer 42, the thickness of the ultraviolet light conversion layer 42 can also be controlled to be 1 to 20 nm. The thickness can be regulated by solution parameters and coating parameters such as the coating thickness of the solution, the ratio of quantum dots to organic solvents in the solution. Among them, in the process of preparing the ultraviolet light conversion layer 42, the thickness of the ultraviolet light conversion layer 42 is also related to the size of the quantum dots. Therefore, according to user needs, the structure of the ultraviolet light conversion layer 42 desired by the user, such as the thickness of the ultraviolet light conversion layer 42, the distribution and width of the conductive channel 43, can be obtained by adjusting the size of the quantum dots, the ratio of quantum dots to organic solvents in the solution, the coating thickness of the solution, etc. For example, the thickness of the ultraviolet light conversion layer 42 can be 1 nm, 2 nm, 4 nm, 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 17 nm, 18 nm, 20 nm, etc. In a preferred embodiment, the thickness of the ultraviolet light conversion layer 42 can be 1 to 15 nm. For example, the thickness of the ultraviolet light conversion layer 42 may be 1 nm, 2 nm, 4 nm, 5 nm, 7 nm, 8 nm, 10 nm, 12 nm, 13 nm, 15 nm, etc., so as to achieve a better light utilization effect of the solar cell.

[0101] The first transparent conductive film layer 41 and the second transparent conductive film layer 44 prepared above may include: a single transparent film layer or a stacked transparent film layer formed of metal oxide and / or metal nitride and a third doping element doped in the single transparent film layer or the stacked transparent film layer, wherein:

[0102] The metal oxide and / or metal nitride is any one or more combinations of the following materials:

[0103] Indium oxide, tin oxide, zinc oxide, cadmium oxide and titanium nitride;

[0104] The doping element doped in the single-layer transparent film layer or the stacked transparent film layer is any one or more of the following elements:

[0105] Indium, tin, calcium, aluminum, cadmium, zinc, cerium and fluorine.

[0106] Further, the sum of the thicknesses of the first transparent conductive film layer 41 and the second transparent conductive film layer 44 prepared above is 1 to 100 nm, for example, the sum of the thicknesses of the first transparent conductive film layer 41 and the second transparent conductive film layer 44 can be 1 nm, 4 nm, 5 nm, 8 nm, 10 nm, 15 nm, 20 nm, 24 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, etc. Preferably, the sum of the thicknesses of the first transparent conductive film layer 41 and the second transparent conductive film layer 44 prepared above is generally controlled to be 60 to 80 nm, for example, the sum of the thicknesses of the first transparent conductive film layer 41 and the second transparent conductive film layer 44 can be 60 nm, 62 nm, 65 nm, 66 nm, 68 nm, 70 nm, 73 nm, 75 nm, 78 nm, 80 nm, etc.

[0107] Furthermore, the first transparent conductive film layer 41 and the second transparent conductive film layer 44 can be prepared by magnetron sputtering. In the process of preparing the first transparent conductive film layer 41 and the second transparent conductive film layer 44, oxygen and hydrogen can be introduced into the chamber to achieve hydrogen doping of the first transparent conductive film layer 41 and the second transparent conductive film layer 44, so as to improve the carrier mobility of the first transparent conductive film layer 41 and the second transparent conductive film layer 44, thereby increasing the conductivity of the first transparent conductive film layer 41 and the second transparent conductive film layer 44.

[0108] Furthermore, for the above preparation method, after preparing the second transparent conductive film layer 44, the method may further include: preparing the front metal electrode 50. The preparation process of the front metal electrode 50 may also be implemented by using the existing metal electrode preparation process.

[0109] Furthermore, the preparation method may further include stacking a back intrinsic silicon-containing film layer 60 , a second doped silicon-containing film layer 70 , a third transparent conductive film layer 80 and a back metal electrode 90 on the second main surface of the substrate 10 from inside to outside.

[0110] The conductivity type of the doping element contained in the prepared second doped silicon-containing film layer 70 is opposite to the conductivity type of the substrate 10. For example, when the substrate 10 is an N-type conductive silicon substrate, the conductivity type of the doping element contained in the second doped silicon-containing film layer 70 is P-type, such as boron, aluminum, etc.; when the substrate 10 is a P-type conductive silicon substrate, the conductivity type of the doping element contained in the second doped silicon-containing film layer 70 can be N-type, such as phosphorus, etc.

[0111] The prepared back intrinsic silicon-containing film layer 60 may be a single layer or a stacked layer formed of any one or more of the following materials: microcrystalline silicon, nano silicon, amorphous silicon, silicon oxide and silicon carbide.

[0112] In addition, the thickness of the back intrinsic silicon-containing film layer 60 can be 1 to 50 nm; for example, the thickness of the back intrinsic silicon-containing film layer 60 can be 1 nm, 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 23 nm, 25 nm, 27 nm, 30 nm, 33 nm, 35 nm, 38 nm, 40 nm, 45 nm, 48 nm, 50 nm, etc.

[0113] The second doped silicon-containing film layer 70 is a single layer or a stacked layer formed of any one or more of the following materials doped with an activated second doping element: microcrystalline silicon, nano silicon, amorphous silicon, silicon oxide, and silicon carbide. It can be understood that the specific implementation of doping the activated second doping element in the film layer is generally to first dope the second doping element into the film layer and activate the second doping element by annealing.

[0114] Furthermore, the thickness of the prepared second doped silicon-containing film layer 70 may be 1-50 nm. For example, the thickness of the second doped silicon-containing film 70 may be 1 nm, 2 nm, 5 nm, 8 nm, 10 nm, 15 nm, 18 nm, 20 nm, 25 nm, 28 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc.

[0115] The prepared third transparent conductive film layer 80 may include: a single transparent film layer or a stacked transparent film layer formed of metal oxide and / or metal nitride and a third doping element doped in the single transparent film layer or the stacked transparent film layer, wherein:

[0116] The metal oxide and / or metal nitride is any one or more combinations of the following materials:

[0117] Indium oxide, tin oxide, zinc oxide, cadmium oxide and titanium nitride;

[0118] The third doping element is any one or more of the following elements:

[0119] Indium, tin, calcium, aluminum, cadmium, zinc, cerium and fluorine.

[0120] Among them, the thickness of the prepared third transparent conductive film layer 80 can be 1 to 100 nm; for example, the thickness of the third transparent conductive film layer 80 can be 1 nm, 4 nm, 5 nm, 8 nm, 10 nm, 15 nm, 20 nm, 24 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, etc.

[0121] Furthermore, the prepared back metal electrode 90 may be any one of the following electrodes or a laminated electrode formed by the following multiple electrodes:

[0122] Silver electrodes, copper electrodes, silver alloy electrodes, copper alloy electrodes, and multilayer electrodes formed of nickel, copper and silver.

[0123] The back intrinsic silicon-containing film layer 60 , the second doped silicon-containing film layer 70 , the third transparent conductive film layer 80 and the back metal electrode 90 can also be prepared by using existing preparation processes.

[0124] It is worth noting that the preparation method provided in the embodiment of the utility model may further include the process of preparing other functional film layers, for example, the process of preparing an anti-reflection layer, etc.

[0125] The above preparation method can be realized by adding a preparation process of the ultraviolet light conversion layer 42 to the existing solar cell process, that is, only a coating process such as spin coating or spray coating needs to be added to the existing solar cell process. Therefore, the solar cell process provided by the embodiment of the utility model is simple and can effectively control the production cost.

[0126] The introduction provided in the above steps is only used to help understand the method, structure and core idea of ​​the utility model. For ordinary technicians in this technical field, the utility model can also be improved and modified without departing from the principle of the utility model, and these improvements and modifications also fall within the scope of protection of the claims of the utility model.

Claims

1. A solar cell, characterized in that: include: A substrate (10), a front intrinsic silicon-containing film layer (20), a first doped silicon-containing film layer (30) and a light conversion conductive structure (40) stacked from inside to outside on a first main surface of the substrate (10), wherein: The light conversion conductive structure (40) comprises: a first transparent conductive film layer (41), an ultraviolet light conversion layer (42), a conductive channel (43) and a second transparent conductive film layer (44), wherein: The ultraviolet light conversion layer (42) is located between the first transparent conductive film layer (41) and the second transparent conductive film layer (44), and is used for converting ultraviolet light into visible light; The conductive channel (43) is embedded in the ultraviolet light conversion layer (42) and is used to conduct the first transparent conductive film layer (41) and the second transparent conductive film layer (44).

2. The solar cell according to claim 1, characterized in that The conductive channel (43) is formed by the area of ​​the ultraviolet light conversion layer (42) that is not occupied by quantum dots.

3. The solar cell according to claim 1 or 2, characterized in that: The thickness of the ultraviolet light conversion layer (42) is 1 to 20 nm.

4. The solar cell according to claim 1, characterized in that The first transparent conductive film layer (41) is located between the first doped silicon-containing film layer (30) and the ultraviolet light conversion layer (42); The thickness of the first transparent conductive film layer (41) is greater than the thickness of the second transparent conductive film layer (44).

5. The solar cell according to claim 1 or 4, characterized in that: The total thickness of the first transparent conductive film layer (41) and the second transparent conductive film layer (44) is 1 to 100 nm.

6. The solar cell according to claim 1, characterized in that Also includes: A front metal electrode (50), wherein The front metal electrode (50) is disposed on the second transparent conductive film layer (44) and is electrically connected to the second transparent conductive film layer (44); and / or, The thickness of the front intrinsic silicon-containing film layer (20) is 1 to 50 nm; and / or, The thickness of the first doped silicon-containing film layer (30) is 1 to 50 nm; and / or, The first doped silicon-containing film layer (30) is a single layer or a stacked layer; and / or, The front intrinsic silicon-containing film layer (20) is a single layer or a stacked layer; and / or, The second transparent conductive film layer (44) is a single-layer transparent film layer or a stacked transparent film layer; and / or, The first transparent conductive film layer (41) is a single-layer transparent film layer or a stacked transparent film layer.

7. The solar cell according to any one of claims 1, 2 and 6, characterized in that: Also includes: A back intrinsic silicon-containing film layer (60), a second doped silicon-containing film layer (70), a third transparent conductive film layer (80) and a back metal electrode (90) are stacked from inside to outside on the second main surface of the substrate (10).

8. The solar cell according to claim 7, characterized in that: The thickness of the back intrinsic silicon-containing film layer (60) is 1 to 50 nm; and / or, The thickness of the second doped silicon-containing film layer (70) is 1 to 50 nm; and / or, The thickness of the third transparent conductive film layer (80) is 1-100 nm.

9. The solar cell according to claim 8, characterized in that The back intrinsic silicon-containing film layer (60) is a single layer or a stacked layer; and / or, The second doped silicon-containing film layer (70) is a single-layer or stacked-layer film layer.

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