Solar cell and preparation method thereof

Abstract

The invention discloses a solar cell and a preparation method thereof. The solar cell comprises a first antireflection layer, a substrate, a second antireflection layer, a light absorption layer and a first carrier transport layer which are stacked, the substrate comprises a first surface and a second surface which are oppositely arranged, and the second surface is a light emitting surface; the first antireflection layer is located on the first surface of the substrate, and the second antireflection layer is located on the second surface of the substrate; the first antireflection layer is used for cutting off ultraviolet light and resisting angle reflection; the second antireflection layer is used for reducing reflection of light. The service life of the cell can be effectively prolonged, and the photoelectric conversion efficiency of the cell is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a solar cell and a preparation method thereof. Background Art

[0002] With the increasing global energy demand and the gradual depletion of fossil fuels, the energy crisis is becoming increasingly serious. Therefore, the development of efficient and renewable new energy has become a focus of global attention. As a highly efficient photovoltaic technology, the improvement of the photoelectric conversion efficiency of perovskite solar cells is of great significance to alleviating the energy crisis and meeting energy needs.

[0003] However, the current photovoltaic conversion efficiency of perovskite solar cells still faces huge challenges. To achieve efficient photovoltaic conversion, not only strong light absorption ability is required, but also other factors need to be considered, such as the performance of the electron transport layer, energy loss inside the battery, etc. The research and exploration of these contents are mainly about the optimization of the internal structure of the battery, and the process is relatively complicated. Summary of the invention

[0004] The present invention provides a solar cell and a preparation method thereof, which can effectively prolong the service life of the battery and improve the photoelectric conversion efficiency of the battery.

[0005] According to one aspect of the present invention, there is provided a solar cell, comprising:

[0006] A first anti-reflection layer, a substrate, a second anti-reflection layer, a light absorbing layer and a first carrier transport layer are stacked;

[0007] The substrate comprises a first surface and a second surface which are arranged opposite to each other, the second surface being a light emitting surface; a first anti-reflection layer is located on the first surface of the substrate, and a second anti-reflection layer is located on the second surface of the substrate; the first anti-reflection layer is used for filtering light of different wavelength bands and resisting angle reflection; and the second anti-reflection layer is used for reducing reflection of light.

[0008] Optionally, the second anti-reflection layer includes a stacked conductive layer, a second carrier transport layer and at least one anti-reflection unit; each anti-reflection unit includes a stacked buffer layer and a third carrier transport layer, and the third carrier transport layer is located on a side of the buffer layer away from the second carrier transport layer;

[0009] The refractive index of the material of the conductive layer is greater than that of the material of the second carrier transport layer, and the refractive index of the material of the buffer layer is greater than that of the material of the third carrier transport layer; the first carrier transport layer and the second carrier transport layer have opposite charges, and the second carrier transport layer and the third carrier transport layer have the same charge.

[0010] Optionally, the first anti-reflection layer includes a filter or a plurality of stacked filter units;

[0011] Each filter unit includes a first filter layer and a second filter layer stacked together, wherein the first filter layer is located on a side of the second filter layer away from the substrate; and the refractive index of the material of the first filter layer is greater than the refractive index of the material of the second filter layer.

[0012] Optionally, the surface of the conductive layer away from the substrate includes a plurality of protrusions; or,

[0013] The first surface of the substrate includes a plurality of protrusions; or,

[0014] The second surface of the substrate includes a plurality of protrusions; or,

[0015] The first surface and the second surface of the substrate, and the surface of the conductive layer away from the substrate all include a plurality of protrusions.

[0016] Optionally, the solar cell further comprises:

[0017] A reflective layer, the reflective layer is located on a side of the first carrier transport layer away from the substrate; the reflective layer covers the first carrier transport layer;

[0018] The reflective layer comprises a back plate and a reflective sublayer, wherein the back plate is located on a side of the reflective sublayer away from the first carrier transport layer.

[0019] Optionally, the reflective sublayer includes a metal layer or a plurality of reflective units stacked in layers; each reflective unit includes a first reflective layer and a second reflective layer stacked in layers, and the first reflective layer is located on a side of the second reflective layer away from the back plate;

[0020] The refractive index of the material of the first reflective layer is greater than the refractive index of the material of the second reflective layer.

[0021] Optionally, the thickness of the first reflective layer is 30nm-100nm;

[0022] The thickness of the second reflective layer is 60nm-200nm;

[0023] The thickness of the second anti-reflection layer is 200nm-1500nm.

[0024] Optionally, the material of the conductive layer includes any one of indium tin oxide and aluminum zinc oxide;

[0025] The material of the second carrier transport layer and the third carrier transport layer includes any one of magnesium fluoride, lithium fluoride and zinc oxide;

[0026] The material of the buffer layer includes any one of tin oxide, titanium oxide and aluminum oxide.

[0027] According to another aspect of the present invention, there is provided a method for preparing a solar cell, comprising:

[0028] A first anti-reflection layer is formed on the first surface of the substrate; the substrate comprises a first surface and a second surface arranged opposite to each other, the second surface being a light emitting surface; the first anti-reflection layer is used for filtering light of different wavelength bands and resisting angle reflection;

[0029] forming a second anti-reflection layer on the second surface of the substrate; the second anti-reflection layer is used to reduce reflection of light;

[0030] forming a light absorbing layer on a side of the second anti-reflection layer away from the substrate;

[0031] A first carrier transport layer is formed on a side of the light absorbing layer away from the substrate.

[0032] Optionally, forming a first anti-reflection layer on the first surface of the substrate includes:

[0033] forming a first anti-reflection layer on the first surface of the substrate by physical vapor deposition or chemical vapor deposition;

[0034] Forming a second anti-reflection layer on the second surface of the substrate includes:

[0035] A second anti-reflection layer is formed on the second surface of the substrate by physical vapor deposition or chemical vapor deposition.

[0036] The solar cell provided by the technical solution of the embodiment of the present invention includes a first anti-reflection layer, a substrate, a second anti-reflection layer, a light absorbing layer and a first carrier transport layer which are stacked; the substrate includes a first surface and a second surface which are arranged opposite to each other, and the second surface is a light emitting surface; the first anti-reflection layer is located on the first surface of the substrate, and the second anti-reflection layer is located on the second surface of the substrate; the first anti-reflection layer is used to filter light of different wavelengths and resist angle reflection; the second anti-reflection layer is used to reduce the reflection of light. In the embodiment of the present invention, the first anti-reflection layer can filter light of different wavelengths, and can effectively filter out light of wavelengths that are harmful to the solar cell, effectively extending the service life of the cell, and the first anti-reflection layer can resist angle reflection, and can improve the utilization rate of light; the second anti-reflection layer can reduce the reflection of light, so that more light enters the interior of the solar cell, further improving the utilization rate of light, thereby improving the photoelectric conversion efficiency of the solar cell.

[0037] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 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 description of 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 creative work.

[0039] Figure 1 It is a schematic diagram of the structure of a solar cell provided by an embodiment of the present invention.

[0040] Figure 2 It is a schematic diagram of different incident angles of light provided by an embodiment of the present invention.

[0041] Figure 3 4 is a wavelength-reflectivity relationship diagram of a second anti-reflection layer provided in an embodiment of the present invention.

[0042] Figure 4 This is a wavelength-transmittance relationship diagram of a second anti-reflection layer provided by an embodiment of the present invention.

[0043] Figure 5 This is a wavelength-transmittance relationship diagram of a first anti-reflection layer provided by an embodiment of the present invention.

[0044] Figure 6 This is another wavelength-transmittance relationship diagram of the first anti-reflection layer provided by an embodiment of the present invention.

[0045] Figure 7 This is a wavelength-reflectivity relationship diagram of a first anti-reflection layer provided by an embodiment of the present invention.

[0046] Figure 8 This is a wavelength-incident angle-transmittance relationship diagram of a first anti-reflection layer provided by an embodiment of the present invention.

[0047] Fig. 9 It is a schematic diagram of the structure of another solar cell provided by an embodiment of the present invention.

[0048] Fig.10 It is a schematic diagram of the structure of another solar cell provided by an embodiment of the present invention.

[0049] Fig.11 It is a schematic diagram of the structure of another solar cell provided by an embodiment of the present invention.

[0050] Fig.12 It is a schematic diagram of the structure of another solar cell provided by an embodiment of the present invention.

[0051] Fig.13 This is a wavelength-reflectivity relationship diagram of a reflective layer provided by an embodiment of the present invention.

[0052] Fig.14 It is a flow chart of a method for preparing a solar cell improved by an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0054] It should be noted that the terms "first", "second", etc. in the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or devices.

[0055] An embodiment of the present invention provides a solar cell. Figure 1 is a schematic diagram of the structure of a solar cell provided by an embodiment of the present invention, with reference to Figure 1 The solar cell includes: a first anti-reflection layer 20, a substrate 10, a second anti-reflection layer 30, a light absorbing layer 40 and a first carrier transport layer 50 which are stacked; the substrate 10 includes a first surface 11 and a second surface 12 which are arranged opposite to each other, and the second surface 12 is a light emitting surface; the first anti-reflection layer 20 is located on the first surface 11 of the substrate 10, and the second anti-reflection layer 30 is located on the second surface 12 of the substrate 10; the first anti-reflection layer 20 is used to filter light of different wavelength bands and resist angle reflection; the second anti-reflection layer 30 is used to reduce the reflection of light.

[0056] Among them, the solar cell can be a regular structure perovskite solar cell or a reverse structure perovskite solar cell; the substrate 10 can be a fluorine-doped tin oxide (FTO) substrate; the light absorption layer 40 can absorb light of a specific wavelength, and the first carrier transport layer 50 can be a hole transport layer. Figure 2It is a schematic diagram of different incident angles of light provided by an embodiment of the present invention. θ1, θ2, and θ3 are the angles formed by light incident from different directions and the solar panel, respectively, which are called incident angles. The first anti-reflection layer 20 can effectively resist the difference in light utilization caused by light incident from different angles. Exemplarily, the incident angle can be 0°-60°, which can effectively reduce the reflection of light incident on the surface of the solar panel at different angles, improve the transmittance of light, and thus improve the utilization of light. The film structure design of the present invention can effectively resist the difference in the amount of light entering the solar cell due to different angles of sunlight irradiation, and further improve the stability of the incident light intensity and the stability of the photoelectric conversion efficiency of the calcium solar cell.

[0057] The second anti-reflection layer 30 can be formed by chemical vapor deposition or physical vapor deposition; the second anti-reflection layer 30 can be obtained by reasonable design of high and low refractive index materials, and the high and low refractive index materials can be designed into specific structures required inside the solar cell, such as a conductive layer and an electron transport layer; in the second anti-reflection layer 30, reasonable design of high and low refractive index materials and thicknesses can also form a good interference effect, which can reduce the reflection of light on the second surface 12 of the substrate 10 after passing through the substrate 10, and can allow more light to enter the light absorbing layer 40, further improving the utilization rate of light. Figure 3 is a wavelength-reflectivity relationship diagram of a second anti-reflection layer provided in an embodiment of the present invention, with reference to Figure 3 , the horizontal axis is the wavelength, the vertical axis is the reflectivity, when the wavelength is greater than 400nm, the reflectivity is less than 10% as the wavelength increases, and when the wavelength is less than 400nm, the smaller the wavelength, the greater the reflectivity; Figure 4 is a wavelength-transmittance relationship diagram of a second anti-reflection layer provided in an embodiment of the present invention, with reference to Figure 4 The horizontal axis is wavelength, and the vertical axis is transmittance. When the wavelength is greater than 400nm, the transmittance is greater than 90%; when the wavelength is less than 400nm, the greater the wavelength, the greater the transmittance.

[0058] Specifically, the first anti-reflection layer 20 can adopt a single-layer structure or a multi-layer structure, which is used to filter light of different bands and resist angle reflection. The first anti-reflection layer 20 can be formed by chemical vapor deposition or physical vapor deposition. For example, if the solar cell is a perovskite solar cell, the properties of the perovskite material will be degraded by light, especially the light in the ultraviolet band will greatly shorten the service life of the perovskite solar cell, seriously affecting the promotion and use of the perovskite solar cell. At this time, the single-layer structure of the first anti-reflection layer 20 can be set as an ultraviolet cut-off filter, and the cut-off wavelength can be designed to be less than 400nm, which can effectively filter out the ultraviolet light band that is harmful to the perovskite cell material and extend the service life of the cell. Alternatively, the first anti-reflection layer can be set as a multi-layer structure, and the multi-layer structure can be a plurality of filter units, each filter unit includes a first filter layer and a second filter layer stacked, and the first filter layer is located on the side of the second filter layer away from the substrate. According to the design of different thicknesses and materials, it can also effectively filter out the ultraviolet light band that is harmful to the perovskite cell material and extend the service life of the cell.

[0059] For example, if the first anti-reflection layer 20 is an ultraviolet cut-off filter, Figure 5 is a wavelength-transmittance relationship diagram of a first anti-reflection layer provided in an embodiment of the present invention, with reference to Figure 5 , the horizontal axis is wavelength, the vertical axis is transmittance, each line represents the transmittance of light of different wavelengths at different incident angles, and the incident angles are 0°, 30°, 45° and 60° respectively. It can be seen that the transmittance of light above 400nm at different incident angles is not much different. The first anti-reflection layer 20 in the present invention can resist angular interference, and the transmittance of ultraviolet light below 400nm is low, which can cut off the ultraviolet light. Figure 6 is another wavelength-transmittance relationship diagram of the first anti-reflection layer provided in an embodiment of the present invention, referring to Figure 6 , Figure 6 is the log value of transmittance. Figure 7 is a wavelength-reflectivity relationship diagram of a first anti-reflection layer provided in an embodiment of the present invention, with reference to Figure 7 The horizontal axis is wavelength, and the vertical axis is reflectivity. The reflectivity of ultraviolet light below 400nm is higher, which can cut off the ultraviolet light. Figure 8 is a wavelength-incident angle-transmittance relationship diagram of a first anti-reflection layer provided by an embodiment of the present invention, Figure 8 It is a three-dimensional schematic diagram of the wavelength-incident angle-transmittance correspondence, which can observe the transmittance of light of different wavelengths at different incident angles.

[0060] The solar cell provided by the technical solution of the embodiment of the present invention includes a first anti-reflection layer 20, a substrate 10, a second anti-reflection layer 30, a light absorbing layer 40 and a first carrier transport layer 50 which are stacked; the substrate 10 includes a first surface 11 and a second surface 12 which are arranged opposite to each other, and the second surface 12 is a light emitting surface; the first anti-reflection layer 20 is located on the first surface 11 of the substrate 10, and the second anti-reflection layer 30 is located on the second surface 12 of the substrate 10; the first anti-reflection layer 20 is used to filter light of different wavelengths and resist angle reflection; the second anti-reflection layer 30 is used to reduce the reflection of light. In the embodiment of the present invention, the first anti-reflection layer 20 can filter light of different wavelengths, can effectively filter out light of wavelengths that are harmful to the solar cell, effectively extend the service life of the cell, and the first anti-reflection layer 20 can resist angle reflection, which can improve the utilization rate of light; the second anti-reflection layer 30 can reduce the reflection of light, so that more light enters the interior of the solar cell, further improves the utilization rate of light, and thus improves the photoelectric conversion efficiency of the solar cell.

[0061] Optional, Fig. 9 is a schematic diagram of the structure of another solar cell provided by an embodiment of the present invention, referring to Fig. 9 The second anti-reflection layer 30 includes a stacked conductive layer 31, a second carrier transport layer 32 and at least one anti-reflection unit; each anti-reflection unit includes a stacked buffer layer 33 and a third carrier transport layer 34, and the third carrier transport layer 34 is located on the side of the buffer layer 33 away from the second carrier transport layer 32; the refractive index of the material of the conductive layer 31 is greater than the refractive index of the material of the second carrier transport layer 32, and the refractive index of the material of the buffer layer 33 is greater than the refractive index of the material of the third carrier transport layer 34; the first carrier transport layer 50 and the second carrier transport layer 32 carry opposite charges, and the second carrier transport layer 32 and the third carrier transport layer 34 carry the same charge.

[0062] Among them, the conductive layer 31 can be a transparent conductive oxide (TCO) conductive layer, and the material of the conductive layer 3 can also include indium tin oxide (ITO) and aluminum zinc oxide (AZO) or other mixed materials; the second carrier transport layer 32 and the third carrier transport layer 34 can be electron transport layers; the light absorption layer 40 can absorb light of a specific wavelength to generate electron-hole pairs, and the electrons are transmitted to the electron transport layer and injected. At the same time, the holes are transmitted to the hole transport layer, thereby realizing the separation of electron-hole pairs, and the electrons are transported to the substrate 10 by the electron transport layer, and the holes are transported to the backplane by the hole transport layer, connecting the external circuit to form a closed loop, thereby generating photocurrent. The second anti-reflection layer 30 can be designed with a film structure of 4 to 24 layers; the materials of the electron transport layer (ETL) include magnesium fluoride (MgF2), lithium fluoride (LiF), zinc oxide (ZnO) or other mixed materials; the materials of the hole transport layer (HTL) include copper oxide (CuO), nickel oxide (NiO) or other mixed materials; the materials of the buffer layer include tin oxide (SnO2), titanium oxide (TiO2), aluminum oxide (Al2O3) or other mixed materials; the anti-reflection effect can be achieved as long as a reasonable film structure design is used.

[0063] Exemplarily, the second anti-reflection layer 30 includes a stacked high refractive index material TCO conductive layer, a low refractive index material magnesium fluoride (MgF2) electron transport layer, a high refractive index material tin dioxide (SnO2) buffer layer and a low refractive index material magnesium fluoride (MgF2) electron transport layer. By reasonably designing the high and low refractive index materials and thicknesses in the second anti-reflection layer 30, a good interference effect can be formed, which can reduce the reflection of light on the second surface 12 of the substrate 10 after passing through the substrate 10, and can allow more light to enter the light absorption layer 40, further improving the utilization rate of light.

[0064] Optional, Fig.10 is a schematic diagram of the structure of another solar cell provided by an embodiment of the present invention, referring to Figure 3 and Fig.10 The first anti-reflection layer 20 includes a filter or a plurality of stacked filter units; each filter unit includes a first filter layer 21 and a second filter layer 22 that are stacked, and the first filter layer 21 is located on a side of the second filter layer 22 away from the substrate 10; the refractive index of the material of the first filter layer 21 is greater than the refractive index of the material of the second filter layer 22.

[0065] Among them, reference Figure 3 , Figure 3The first anti-reflection layer 20 can be a single-layer structure and can be a filter. If the solar cell is a perovskite solar cell, the filter can be an ultraviolet light cutoff filter, which can resist the damage and degradation of the perovskite solar cell by ultraviolet light and extend the service life of the battery. If the solar cell is other types of cells, other types of filters can also be set as needed, such as infrared light cutoff filters.

[0066] Specifically, the material of the first filter layer 21 and the material of the second filter layer 22 can be selected from any one of TiO2, Ta2O5, SnO2, SiO2, Al3O2, ZrO, ZnO, NiO2 and MgF2, but it is necessary to ensure that the refractive index of the material of the first filter layer is greater than the refractive index of the material of the second filter layer. Exemplarily, the first anti-reflection layer 20 can use materials including but not limited to TiO2 and SiO2 through stacking of high and low refractive index materials (HL) for 6 cycles, 9 cycles or even more than 12 cycles. By designing different materials and the thickness of different materials, the first anti-reflection layer 20 can be designed as a functional film layer with a cut-off wavelength of ultraviolet light. The cut-off wavelength can be designed to be less than 400nm, and the wavelength of the visible light to infrared light band is 400nm to 1000nm. The high transmittance design of the visible light to infrared light band can effectively filter out the ultraviolet light band that is harmful to the perovskite battery material and extend the service life of the battery. The first anti-reflection layer 20 can effectively resist the difference in light utilization caused by light incident from different angles, and can effectively reduce the reflection of light incident from the surface of the solar cell panel at different angles, thereby improving the light transmittance and thus improving the light utilization.

[0067] Optionally, the surface of the conductive layer away from the substrate includes multiple protrusions; or, the first surface of the substrate includes multiple protrusions, or, the second surface of the substrate includes multiple protrusions; or, the first surface and the second surface of the substrate, and the surface of the conductive layer away from the substrate all include multiple protrusions.

[0068] Among them, the surface of the conductive layer away from the substrate includes multiple protrusions; or, the first surface of the substrate includes multiple protrusions, or, the second surface of the substrate includes multiple protrusions; or, the first surface and the second surface of the substrate, and the surface of the conductive layer away from the substrate all include multiple protrusions; multiple protrusions can increase the optical path of the incident light and increase the emission range of the emitted light. The more light is emitted, the higher the light utilization rate, thereby improving the photoelectric conversion efficiency.

[0069] Optional, Fig.11 is a schematic diagram of the structure of another solar cell provided by an embodiment of the present invention, referring to Fig.11The solar cell also includes: a reflective layer 60, which is located on the side of the first carrier transport layer 50 away from the substrate 10; the reflective layer 60 covers the first carrier transport layer 50; the reflective layer 60 includes a back plate 62 and a reflective sublayer 61, and the back plate 62 is located on the side of the reflective sublayer 61 away from the first carrier transport layer 50.

[0070] The backplane 62 may be a glass backplane; a reflective sublayer 61 having strong reflection may be produced on the packaged backplane by using a physical vapor deposition method or a chemical vapor deposition method. Fig.11 The blue arrow in the figure represents the schematic diagram of the incident light inside the battery, which can make the light pass through the interior of the solar cell and then be reflected twice at the reflective sublayer 61. The light after the second reflection will continue to pass through the interior of the solar cell, thereby improving the secondary utilization rate of the light.

[0071] Optional, Fig.12 is a schematic diagram of the structure of another solar cell provided by an embodiment of the present invention, referring to Fig.11 and Fig.12 The reflective sublayer 61 includes a metal layer or a plurality of stacked reflective units; each reflective unit includes a first reflective layer 601 and a second reflective layer 602 which are stacked, and the first reflective layer 601 is located on a side of the second reflective layer 602 away from the back plate 62; the refractive index of the material of the first reflective layer 601 is greater than the refractive index of the material of the second reflective layer 602.

[0072] Among them, the metal layer can be a single layer or multilayer metal material of a certain thickness such as silver Ag, aluminum Al, etc. The reflective unit is a strong reflective layer DBR obtained by cross-circulating the dielectric material through the high refractive index H and the low refractive index material L. The thickness of the first reflective layer 601 is 30nm-100nm, and the thickness of the second reflective layer 602 is 60nm-200nm. A reflective unit with a thickness of 400nm to 1000nm can be obtained by 19 consecutive cycles. The reflectivity of the entire band can almost reach more than 90%, which can make the light pass through the interior of the solar cell and then be reflected twice in the reflective sublayer 61. The light after the second reflection will continue to pass through the interior of the solar cell, thereby improving the secondary utilization rate of light. Fig.13 is a wavelength-reflectivity relationship diagram of a reflective layer provided in an embodiment of the present invention, with reference to Fig.13 , Fig.13 The reflective layer is formed by multiple reflective units. The horizontal axis is the wavelength and the vertical axis is the reflectivity. It can be seen that the reflectivity at a wavelength above 400 nm is greater than 90%.

[0073] Optionally, the thickness of the first reflective layer is 30nm-100nm; the thickness of the second reflective layer is 60nm-200nm; and the thickness of the second anti-reflective layer is 200nm-1500nm.

[0074] The thickness of the first reflective layer is 30nm-100nm; the thickness of the second reflective layer is 60nm-200nm; by reasonably setting the thickness and material of the first reflective layer and the second reflective layer, the reflectivity of light can be improved and the secondary utilization rate of light can be improved. The thickness of the second anti-reflective layer is 200nm-1500nm; it can reduce the reflection of light passing through the second surface of the substrate, so that more light can enter the light absorption layer inside the solar cell, further improving the utilization rate.

[0075] Optionally, the material of the conductive layer includes any one of indium tin oxide and aluminum zinc oxide; the material of the second carrier transport layer and the third carrier transport layer includes any one of magnesium fluoride, lithium fluoride and zinc oxide; the material of the buffer layer includes any one of tin oxide, titanium oxide and aluminum oxide.

[0076] Among them, the above materials can enable the second anti-reflection layer to achieve anti-reflection effect as long as a reasonable film layer structure is designed.

[0077] The embodiment of the present invention provides a method for preparing a solar cell based on the above embodiment. Fig.14 is a flow chart of a method for preparing a solar cell improved by an embodiment of the present invention, with reference to Fig.14 , the preparation method comprises:

[0078] S110, forming a first anti-reflection layer on the first surface of the substrate; the substrate comprises a first surface and a second surface arranged opposite to each other, the second surface being a light emitting surface; the first anti-reflection layer is used for filtering light of different wavelength bands and resisting angle reflection.

[0079] Wherein, the first anti-reflection layer is formed on the first surface of the substrate by physical vapor deposition or chemical vapor deposition.

[0080] S120, forming a second anti-reflection layer on the second surface of the substrate; the second anti-reflection layer is used to reduce reflection of light.

[0081] Wherein, the second anti-reflection layer is formed on the second surface of the substrate by physical vapor deposition or chemical vapor deposition.

[0082] S130, forming a light absorbing layer on a side of the second anti-reflection layer away from the substrate.

[0083] The light absorbing layer may be formed on the side of the second anti-reflection layer away from the substrate by a conventional deposition process.

[0084] S140, forming a first carrier transport layer on a side of the light absorption layer away from the substrate.

[0085] The first carrier transport layer can be formed on the side of the light absorbing layer away from the substrate by conventional deposition process, and then the reflective layer can be prepared on the side of the first carrier transport layer away from the light absorbing layer.

[0086] In the method for preparing a solar cell provided by the technical solution of the embodiment of the present invention, the first anti-reflection layer can filter light of different bands, and can effectively filter out light of bands that are harmful to the solar cell, effectively extending the service life of the battery, and the first anti-reflection layer can resist angle reflection, and can improve the utilization rate of light; the second anti-reflection layer can reduce the reflection of light, so that more light enters the interior of the solar cell, further improving the utilization rate of light, thereby improving the photoelectric conversion efficiency of the solar cell.

[0087] Optionally, forming a first anti-reflection layer on the first surface of the substrate includes:

[0088] forming a first anti-reflection layer on the first surface of the substrate by physical vapor deposition or chemical vapor deposition;

[0089] Forming a second anti-reflection layer on the second surface of the substrate includes:

[0090] A second anti-reflection layer is formed on the second surface of the substrate by physical vapor deposition or chemical vapor deposition.

[0091] The inventors found that if the sol-gel method is used to prepare the anti-reflection film, the performance of the film layer is greatly affected by the process, and the anti-reflection effect of the film layer produced by this method is limited; the film layer structure has poor stability and is easily polluted and damaged by the environment, which ultimately affects the anti-reflection effect. However, when etching or nanoimprinting is used to prepare the anti-reflection film, the etching process is difficult, the efficiency is low, and the equipment cost is high; nanoimprinting usually requires a more complex process to be made, and the imprinted glue faces a huge test in harsh use environments, and both etching and nanoimprinting technology are difficult to achieve mass production on larger substrates. The embodiment of the present invention uses physical vapor deposition or chemical vapor deposition to realize the production of anti-reflection film on the substrate. Due to the technical characteristics of these two deposition methods themselves, the thickness of the film layer is precisely controllable, and the process is simple, which can be more easily achieved in mass production on large-area components; the selectivity of thin film materials is more, and suitable materials can be selected according to different needs, and the production stability is good and the yield is high, and no high production cost is required. It is also possible to achieve filtering or transmission of light in different bands according to different requirements. For example, it can improve the transmittance of light in the available wavelengths, filter out ultraviolet, infrared and other wavelengths that are harmful to solar cell materials, effectively extend the service life of the battery, and improve the photoelectric conversion efficiency of the battery.

[0092] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0093] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A solar cell, characterized in that: include: A first anti-reflection layer, a substrate, a second anti-reflection layer, a light absorbing layer and a first carrier transport layer are stacked; The substrate comprises a first surface and a second surface which are arranged opposite to each other, the second surface being a light emitting surface; the first anti-reflection layer is located on the first surface of the substrate, and the second anti-reflection layer is located on the second surface of the substrate; the first anti-reflection layer is used for filtering light of different wavelength bands and resisting angle reflection; the second anti-reflection layer is used for reducing reflection of light.

2. The solar cell according to claim 1, characterized in that: The second anti-reflection layer comprises a stacked conductive layer, a second carrier transport layer and at least one anti-reflection unit; each of the anti-reflection units comprises a stacked buffer layer and a third carrier transport layer, and the third carrier transport layer is located on a side of the buffer layer away from the second carrier transport layer; The refractive index of the material of the conductive layer is greater than the refractive index of the material of the second carrier transport layer, and the refractive index of the material of the buffer layer is greater than the refractive index of the material of the third carrier transport layer; the first carrier transport layer and the second carrier transport layer have opposite charges, and the second carrier transport layer and the third carrier transport layer have the same charge.

3. The solar cell according to claim 1, characterized in that: The first anti-reflection layer includes a filter or a plurality of stacked filter units; Each filter unit includes a first filter layer and a second filter layer stacked together, wherein the first filter layer is located on a side of the second filter layer away from the substrate; and the refractive index of the material of the first filter layer is greater than the refractive index of the material of the second filter layer.

4. The solar cell according to claim 2, characterized in that: The surface of the conductive layer away from the substrate includes a plurality of protrusions; or, The first surface of the substrate includes a plurality of protrusions; or, The second surface of the substrate includes a plurality of protrusions; or, The first surface and the second surface of the substrate, and the surface of the conductive layer away from the substrate all include a plurality of protrusions.

5. The solar cell according to claim 2, characterized in that: Also includes: a reflective layer, the reflective layer being located on a side of the first carrier transport layer away from the substrate; the reflective layer covering the first carrier transport layer; The reflective layer includes a back plate and a reflective sublayer, and the back plate is located on a side of the reflective sublayer away from the first carrier transport layer.

6. The solar cell according to claim 5, characterized in that: The reflective sublayer includes a metal layer or a plurality of reflective units stacked in layers; each of the reflective units includes a first reflective layer and a second reflective layer stacked in layers, and the first reflective layer is located on a side of the second reflective layer away from the back plate; The refractive index of the material of the first reflective layer is greater than the refractive index of the material of the second reflective layer.

7. The solar cell according to claim 6, characterized in that: The thickness of the first reflective layer is 30nm-100nm; The thickness of the second reflective layer is 60nm-200nm; The thickness of the second anti-reflection layer is 200nm-1500nm.

8. The solar cell according to claim 2, characterized in that: The material of the conductive layer includes any one of indium tin oxide and aluminum zinc oxide; The material of the second carrier transport layer and the third carrier transport layer includes any one of magnesium fluoride, lithium fluoride and zinc oxide; The material of the buffer layer includes any one of tin oxide, titanium oxide and aluminum oxide.

9. A method for preparing a solar cell, characterized in that: include: A first anti-reflection layer is formed on a first surface of a substrate; the substrate comprises a first surface and a second surface arranged opposite to each other, the second surface being a light emitting surface; The first anti-reflection layer is used to filter light of different wavelength bands and resist angle reflection; forming a second anti-reflection layer on the second surface of the substrate; the second anti-reflection layer is used to reduce reflection of light; forming a light absorbing layer on a side of the second anti-reflection layer away from the substrate; A first carrier transport layer is formed on a side of the light absorption layer away from the substrate.

10. The preparation method according to claim 9, characterized in that: Forming a first anti-reflection layer on a first surface of a substrate includes: forming a first anti-reflection layer on the first surface of the substrate by physical vapor deposition or chemical vapor deposition; Forming a second anti-reflection layer on the second surface of the substrate comprises: A second anti-reflection layer is formed on the second surface of the substrate by physical vapor deposition or chemical vapor deposition.

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