Preparation method of solar cell and solar cell

Abstract

The invention discloses a preparation method of a solar cell and the solar cell, and the preparation method comprises the steps: firstly providing an N-type silicon substrate, carrying out boron diffusion doping processing on one side of a first surface of the N-type silicon substrate, and carrying out phosphorus diffusion doping processing on one side of a second surface of the N-type silicon substrate; wherein the first surface is a textured surface, the second surface is a polished surface, then a first passive film layer is formed on the first surface, a second passive film layer is formed on the second surface, then laser grooving treatment is performed on one side of the second passive film layer, and a perovskite laminated structure is formed in a formed groove area; wherein the perovskite laminated structure comprises a first conductive layer, a hole transport layer, a perovskite layer, an electron transport layer, a conductive transition layer and a second conductive layer which are stacked in sequence, the first conductive layer is in contact with the second surface, and finally screen printing and sintering treatment are performed on one side of the first passive film layer and / or one side of the second passive film layer to form an electrode structure. And preparing the solar cell.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of solar cells, and in particular to a method for preparing a solar cell and a solar cell. Background Art

[0002] The update and iteration of photovoltaic cell structure has led to the continuous accumulation of old production capacity, and cost reduction and efficiency improvement have become the key issues of the photovoltaic industry. Compared with P-type crystalline silicon cells, N-type crystalline silicon cells have the advantages of long minority carrier lifetime, no photoinduced degradation, good weak light effect, and small temperature coefficient. They are the hope for crystalline silicon solar cells to break through the theoretical maximum efficiency. In addition, perovskite solar cells are a new type of solar cell technology that has attracted much attention for its high photoelectric conversion efficiency, excellent photoelectric performance, low manufacturing cost, wider application potential, and easy preparation. It can effectively absorb and convert solar light into electrical energy.

[0003] On the one hand, the theoretical limit of the photoelectric conversion efficiency of N-type crystalline silicon cells is 28.7%, the theoretical limit of the photoelectric conversion efficiency of single-junction perovskite solar cells is 31%, the theoretical limit of the photoelectric conversion efficiency of multi-junction perovskite solar cells is 45%, and the theoretical limit of the photoelectric conversion efficiency of crystalline silicon cell stacked perovskite solar cells is 43%. On the other hand, N-type crystalline silicon cells and perovskite solar cells are mostly used in outdoor scenes. Both are sensitive to ultraviolet and infrared wavelengths, which will seriously affect their own reliability. Therefore, this field urgently needs to solve the problem that existing solar cells cannot effectively take into account both high photoelectric conversion efficiency and high reliability. Summary of the invention

[0004] The embodiment of the present invention provides a method for preparing a solar cell and a solar cell, by superimposing a perovskite stacked structure on the back side of an N-type silicon substrate, so as to achieve a higher photoelectric conversion efficiency of the overall solar cell, increase the passivation and anti-ultraviolet attenuation performance of both sides of the N-type silicon substrate, so that the prepared solar cell can effectively take into account both high photoelectric conversion efficiency and high reliability.

[0005] In a first aspect, an embodiment of the present invention provides a method for preparing a solar cell, comprising:

[0006] Providing an N-type silicon substrate, and performing a boron diffusion doping treatment on one side of a first surface of the N-type silicon substrate, and performing a phosphorus diffusion doping treatment on one side of a second surface of the N-type silicon substrate; wherein the first surface and the second surface are two surfaces of the N-type silicon substrate that are opposite to each other, and the first surface is a velvet surface, and the second surface is a polished surface;

[0007] forming a first passivation film layer on the first surface, and forming a second passivation film layer on the second surface;

[0008] A laser groove process is performed on one side of the second passivation film layer, and a perovskite stacked structure is formed in the formed groove area; wherein the perovskite stacked structure includes a first conductive layer, a hole transport layer, a perovskite layer, an electron transport layer, a conductive transition layer and a second conductive layer stacked in sequence, and the first conductive layer is in contact with the second surface;

[0009] Screen printing and sintering are performed on one side of the first passivation film layer and / or one side of the second passivation film layer to form an electrode structure, thereby manufacturing the solar cell.

[0010] Optionally, the material of the first conductive layer includes indium oxide; and / or, the material of the hole transport layer includes nickel oxide and PVK; and / or, the material of the perovskite layer includes CH3NH3PbCl3; and / or, the material of the electron transport layer includes C60; and / or, the material of the conductive transition layer includes zinc oxide; and / or, the material of the second conductive layer includes indium oxide.

[0011] Optionally, the thickness range of the first conductive layer is 110-130nm; and / or, the thickness range of the hole transport layer is 35-55nm; and / or, the thickness range of the perovskite layer is 340-360nm; and / or, the thickness range of the electron transport layer is 20-40nm; and / or, the thickness range of the conductive transition layer is 50-100nm; and / or, the thickness range of the second conductive layer is 270-290nm.

[0012] Optionally, the first passivation film layer includes an anti-ultraviolet attenuation film layer and a first anti-reflection layer; the second passivation film layer includes a second anti-reflection layer;

[0013] Forming a first passivation film layer on the first surface, and forming a second passivation film layer on the second surface, comprising:

[0014] forming the anti-ultraviolet attenuation film layer on the first surface;

[0015] forming the first anti-reflection layer on a side of the anti-ultraviolet attenuation film layer away from the first surface;

[0016] The second anti-reflection layer is formed on the second surface.

[0017] Optionally, the thickness of the anti-ultraviolet attenuation film layer is in the range of 6-10 nm.

[0018] Optionally, the refractive index of the first anti-reflection layer is in a range of 2.2%-2.3%; and / or the refractive index of the second anti-reflection layer is in a range of 2.2%-2.3%.

[0019] Optionally, the material of the anti-ultraviolet attenuation film layer includes aluminum oxide; and / or, the material of the first anti-reflection layer includes silicon nitride; and / or, the material of the second anti-reflection layer includes silicon nitride.

[0020] Optionally, before performing phosphorus diffusion doping on one side of the second surface of the N-type silicon substrate, the method further includes:

[0021] A tunneling oxide layer and a polysilicon layer are sequentially formed on the second surface.

[0022] Optionally, the reflectivity of the suede surface of the first surface is in the range of 8%-9%.

[0023] In a second aspect, an embodiment of the present invention further provides a solar cell, which is prepared by the method for preparing a solar cell as described in any one of the first aspects.

[0024] The embodiment of the present invention provides a method for preparing a solar cell and a solar cell. The preparation method first provides an N-type silicon substrate, and performs a boron diffusion doping treatment on one side of a first surface of the N-type silicon substrate, and performs a phosphorus diffusion doping treatment on one side of a second surface of the N-type silicon substrate; wherein the first surface and the second surface are two surfaces of the N-type silicon substrate that are opposite to each other, and the first surface is a velvet surface, and the second surface is a polished surface, and then a first passivation film layer is formed on the first surface, and a second passivation film layer is formed on the second surface, and then a laser groove is performed on one side of the second passivation film layer, and a perovskite stacked structure is formed in the formed groove area; wherein the perovskite stacked structure includes a first conductive layer, a hole transport layer, a perovskite layer, an electron transport layer, a conductive transition layer and a second conductive layer that are stacked in sequence, and the first conductive layer is in contact with the second surface, and finally screen printing and sintering are performed on one side of the first passivation film layer and / or one side of the second passivation film layer to form an electrode structure to obtain a solar cell. By using the above method, a first surface side of the N-type silicon substrate is subjected to boron diffusion doping treatment, a second surface side of the N-type silicon substrate is subjected to phosphorus diffusion doping treatment, and a passivation film layer is formed on both sides of the N-type silicon substrate, which effectively increases the passivation and anti-ultraviolet attenuation performance of both sides of the N-type silicon substrate, and a perovskite stacked structure is superimposed on the back side of the N-type silicon substrate. The superposition of the two achieves a higher photoelectric conversion efficiency of the overall solar cell, so that the prepared solar cell can effectively take into account both high photoelectric conversion efficiency and high reliability, and the perovskite stacked structure is formed in the groove area of ​​the laser groove, which can further reduce the influence of ultraviolet and infrared on the perovskite cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 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.

[0026] Figure 1 is a schematic flow chart of a method for preparing a solar cell provided by an embodiment of the present invention;

[0027] Figure 2 It is a schematic flow chart of another method for preparing a solar cell provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0029] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. It should be noted that the directional words such as "upper", "lower", "left", "right" and the like described in the embodiments of the present invention are described at the angles shown in the accompanying drawings and should not be understood as limitations on the embodiments of the present invention. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is formed "on" or "under" another element, it can not only be directly formed "on" or "under" another element, but also indirectly formed "on" or "under" another element through an intermediate element. The terms "first", "second", etc. are only used for descriptive purposes and do not represent any order, quantity or importance, but are only used to distinguish different components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific circumstances.

[0030] The term “including” and its variations used in the present invention are open inclusions, that is, “including but not limited to.” The term “based on” means “based at least in part on.” The term “one embodiment” means “at least one embodiment.”

[0031] It should be noted that the concepts such as "first" and "second" mentioned in the present invention are only used to distinguish the corresponding contents, and are not used to limit the order or interdependence.

[0032] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0033] Figure 1 The present invention provides a schematic flow diagram of a method for preparing a solar cell. The method for preparing a solar cell can be applied to outdoor applications to reduce the impact of ultraviolet and infrared radiation on the solar cell. The method for preparing a solar cell can be used to prepare a solar cell. Figure 1 As shown, the preparation method comprises:

[0034] S110, providing an N-type silicon substrate, and performing a boron diffusion doping treatment on one side of a first surface of the N-type silicon substrate, and performing a phosphorus diffusion doping treatment on one side of a second surface of the N-type silicon substrate; wherein the first surface and the second surface are two surfaces of the N-type silicon substrate that are opposite to each other, and the first surface is a velvet surface, and the second surface is a polished surface.

[0035] Specifically, an N-type silicon substrate is provided, and the N-type silicon substrate includes a first surface and a second surface that are separated from each other. Exemplarily, the first surface can be understood as the front side of the N-type silicon substrate, and the second surface can be understood as the back side of the N-type silicon substrate. Exemplarily, the first surface and the second surface of the N-type silicon substrate can be rectangular in shape, the long side length of the rectangle can be 183.75 mm, and the short side length of the rectangle can be 182.2 mm.

[0036] The first surface of the N-type silicon substrate is a velvet surface. Exemplarily, the first surface of the N-type silicon substrate can be subjected to a velvet treatment so that the first surface of the N-type silicon substrate is a velvet surface. Exemplarily, the velvet surface is a pyramid structure when tested under a microscope. Optionally, the reflectivity of the velvet surface of the first surface ranges from 8% to 9%. The velvet treatment can remove organic dirt and metal impurities on the surface of the N-type silicon substrate, remove the mechanical damage layer generated during the wire cutting process of the N-type silicon substrate, reduce the recombination center, and form an undulating velvet surface, so as to utilize the light trapping effect, increase the absorption rate of the N-type silicon substrate to sunlight, reduce the reflectivity, and increase the surface area of ​​the N-type silicon substrate, thereby also increasing the area of ​​the PN junction formed on the surface. Exemplarily, the velvet treatment can use a mixed solution of 32L of concentrated potassium hydroxide (KOH) solution, 10L of velvet additive, and 480L of pure water. The velvet treatment time can be 300s, and the velvet treatment temperature can be 75°C.

[0037] After the first surface of the N-type silicon substrate is textured, a boron diffusion doping treatment may be performed on one side of the first surface of the N-type silicon substrate to form a PN junction on the first surface of the N-type silicon substrate. The junction formation process is to generate semiconductor layers of different conductivity types on a piece of semiconductor substrate material. For example, the square resistance after the boron diffusion doping treatment is 280Ω / sq, and the junction depth of ECV (electrochemical differential capacitance voltage) is 0.55μm.

[0038] After the first surface of the N-type silicon substrate is subjected to boron diffusion doping treatment, the second surface of the N-type silicon substrate can be subjected to chain pickling and alkali polishing treatment to ensure that the second surface of the N-type silicon substrate is a polished surface, so that the N-type silicon substrate forms a polished surface with high reflectivity, thereby improving the flatness of the battery surface, and increasing the reflection of long-wave light to promote the secondary absorption of light, increase the short-circuit current and reduce the leakage current. Exemplarily, the chain pickling treatment can use a mixed solution of 1.5% hydrochloric acid (HCl) solution and 1.2% hydrofluoric acid (HF) solution. Exemplarily, the alkali polishing treatment can use a mixed solution of 12L concentrated potassium hydroxide (KOH) solution, 8L additive (BP55), and 460L pure water, the alkali polishing treatment time can be 280s, and the alkali polishing treatment temperature can be 68°C.

[0039] After the first surface side of the N-type silicon substrate is subjected to boron diffusion doping treatment, the second surface side of the N-type silicon substrate can be further subjected to phosphorus diffusion doping treatment to form a PN junction on the second surface of the N-type silicon substrate. The junction making process is to generate semiconductor layers with different conductivity types on a piece of semiconductor substrate material. Exemplarily, the square resistance after the boron diffusion doping treatment is 38Ω / sq, and the junction depth of the ECV is 1.15μm. It can be understood that this embodiment only describes the example of first performing boron diffusion doping treatment on the first surface side of the N-type silicon substrate, and then performing phosphorus diffusion doping treatment on the second surface side of the N-type silicon substrate. In fact, the second surface side of the N-type silicon substrate can also be subjected to phosphorus diffusion doping treatment, and then the first surface side of the N-type silicon substrate can be subjected to boron diffusion doping treatment, and the first surface side of the N-type silicon substrate can be subjected to boron diffusion doping treatment and the second surface side of the N-type silicon substrate can be subjected to phosphorus diffusion doping treatment at the same time, without specific limitation.

[0040] In addition, after the second surface side of the N-type silicon substrate is subjected to phosphorus diffusion doping treatment, the second surface of the N-type silicon substrate can be subjected to chain pickling and etching treatment to ensure that the second surface of the N-type silicon substrate is clean and free of impurities. Exemplarily, the chain pickling treatment can use a mixed solution of 1.5% hydrochloric acid (HCl) solution and 1.5% hydrofluoric acid (HF) solution. The etching treatment can use a mixed solution of 18L concentrated potassium hydroxide (KOH) solution, 8L additive (BP68), and 480L pure water, the etching treatment time can be 280s, and the etching treatment temperature can be 70°C.

[0041] S120 , forming a first passivation film layer on the first surface, and forming a second passivation film layer on the second surface.

[0042] Specifically, a passivation film layer can be formed on the first surface and the second surface of the N-type silicon substrate by using processes such as atomic layer deposition (ALD), low pressure chemical vapor deposition (LPCVD), plasma enhanced chemical vapor deposition (PECVD), and coating. It can be understood that the first passivation film layer and the second passivation film layer have passivation and anti-ultraviolet attenuation properties, which can effectively prevent the entire solar cell from being affected by ultraviolet and infrared, and further ensure the operational reliability of the entire solar cell.

[0043] S130. Performing laser grooving on one side of the second passivation film layer, and forming a perovskite stacked structure in the formed groove area; wherein the perovskite stacked structure includes a first conductive layer, a hole transport layer, a perovskite layer, an electron transport layer, a conductive transition layer and a second conductive layer stacked in sequence, and the first conductive layer is in contact with the second surface.

[0044] Specifically, laser grooving is performed on one side of the second passivation film layer to expose the second surface of the N-type silicon substrate. The depth of the laser grooving is based on just destroying the second passivation film layer in the corresponding groove area without affecting the second surface of the N-type silicon substrate. For example, it can be 1.1μm. Exemplarily, when laser grooving is performed on one side of the second surface of the N-type silicon substrate, a laser can be used to perform grooving using picosecond green light and laser marking. Exemplarily, the laser power is 8W. In this way, the first conductive layer of the perovskite stacked structure is in contact with the second surface of the N-type silicon substrate, realizing the conduction of electrons between the crystalline silicon cell and the perovskite cell, and further increasing the photoelectric conversion performance between the two.

[0045] After the laser grooving process, a groove area will be formed on one side of the second surface of the N-type silicon substrate, and a perovskite stacking structure can be formed in the groove area to realize the stacking design of the N-type silicon substrate and the perovskite stacking structure, so that the overall solar cell has the excellent performance of the N-type silicon substrate and the perovskite stacking structure, that is, the overall solar cell effectively takes into account high photoelectric conversion efficiency and high reliability. In addition, the perovskite stacking structure is formed in the groove area of ​​the second surface of the N-type silicon substrate. The perovskite stacking structure is equivalent to being surrounded by the second passivation film layer. The second passivation film layer can effectively avoid the influence of ultraviolet and infrared on the perovskite stacking structure, and reduce the sensitivity of the perovskite stacking structure to ultraviolet and infrared wavelengths.

[0046] The perovskite stacked structure includes a first conductive layer, a hole transport layer, a perovskite layer, an electron transport layer, a conductive transition layer and a second conductive layer stacked in sequence, and the first conductive layer is in contact with the second surface. In a specific embodiment, optionally, the material of the first conductive layer includes indium oxide; and / or, the material of the hole transport layer includes nickel oxide and PVK; and / or, the material of the perovskite layer includes CH3NH3PbCl3; and / or, the material of the electron transport layer includes C60; and / or, the material of the conductive transition layer includes zinc oxide; and / or, the material of the second conductive layer includes indium oxide. In another specific embodiment, optionally, the thickness range of the first conductive layer is 110-130nm; and / or, the thickness range of the hole transport layer is 35-55nm; and / or, the thickness range of the perovskite layer is 340-360nm; and / or, the thickness range of the electron transport layer is 20-40nm; and / or, the thickness range of the conductive transition layer is 50-100nm; and / or, the thickness range of the second conductive layer is 270-290nm.

[0047] Exemplarily, the material of the first conductive layer can be indium oxide (Indium Tin Oxide, ITO), and the N-type silicon substrate after the groove is taken, and the magnetron sputtering method is used to deposit ITO in the groove area to form the first conductive layer. During the magnetron sputtering process, by applying a magnetic field, the ion density in the gas can be enhanced, and the uniformity and quality of the ITO film can be improved. Exemplarily, the thickness of the first conductive layer can be 120nm. Exemplarily, the material of the hole transport layer can be nickel oxide (NiO) and PVK, and then NiO and PVK are deposited on the prepared first conductive layer to form the hole transport layer, wherein NiO is used as an electron receiving layer, and PVK is a polymer material with good hole transport properties. Exemplarily, the thickness of the hole transport layer can be 45nm. Exemplarily, the material of the perovskite layer can be CH3NH3PbCl3, and then CH3NH3PbCl3 is deposited on the prepared hole transport layer to form the perovskite layer. Exemplarily, the thickness of the perovskite layer can be 350nm. Exemplarily, the material of the electron transport layer may be C60, and then a layer of C60 is prepared by thermal evaporation on the prepared perovskite layer as the electron transport layer. Exemplarily, the thickness of the electron transport layer may be 30nm. Exemplarily, the material of the conductive transition layer may be zinc oxide (ZnO), and then a dense ZnO layer is deposited on the prepared electron transport layer to form the conductive transition layer. Exemplarily, the thickness of the conductive transition layer may be 70nm. Exemplarily, the material of the second conductive layer may be ITO, and ITO is deposited on the prepared conductive transition layer by magnetron sputtering to form the second conductive layer. Exemplarily, the thickness of the second conductive layer may be 280nm.

[0048] S140, performing screen printing and sintering treatment on one side of the first passivation film layer and / or one side of the second passivation film layer to form an electrode structure to manufacture a solar cell.

[0049] Specifically, screen printing is one of the core processes in the manufacturing process of solar cells, and is mainly used for electrode formation of solar cells. This process uses the basic principle that the mesh holes of the graphic part of the screen are transparent to the slurry, while the mesh holes of the non-graphic part are not transparent to the slurry for printing. During the printing process, the slurry is accurately squeezed onto the N-type silicon substrate through the mesh holes of the screen, and the slurry is evenly distributed on the surface of the solar cell in the form of a wire to form the required electrode pattern. Generally, the slurry for screen printing may include but is not limited to silver paste. The pattern formed by screen printing includes metal grid lines. High-temperature sintering is used to treat the electrode material screen-printed onto the surface of the cell at high temperature, dry the slurry on the N-type silicon substrate, burn out the organic components of the slurry, and the slurry can corrode through the passivation film layer and connect to the PN junction, so that the metal grid line forms a good ohmic contact with the N-type silicon substrate, thereby achieving the purpose of collecting and conducting current.

[0050] Furthermore, the solar cell after the screen printing process is sintered at a temperature of 748 degrees Celsius, and then a light injection process is performed. For example, the temperature of the light injection process can be 528°C, and the light intensity can be 8000W / m 2 The laser induced process after light injection can induce silver-silicon interdiffusion, thereby significantly reducing contact resistance, increasing the fill factor of the battery, and effectively improving the efficiency of the battery cell. For example, the laser power of the laser induced process can be 18W, and the reverse voltage applied to the battery terminal can be 28V.

[0051] In addition, after the perovskite stacked structure is formed in the groove area on the back side of the N-type silicon substrate, a screen printing process can be used to print low-temperature conductive silver paste on one side of the second conductive layer. In this way, the series resistance of the crystalline silicon cell and the perovskite cell is reduced, the filling of the overall solar cell is improved, and the photoelectric conversion efficiency and reliability of the overall solar cell are improved.

[0052] It should also be noted that the solar cell prepared in this embodiment has been subjected to relevant experiments, and it can be concluded that the photoelectric conversion efficiency of the solar cell is as high as 30.85%. After that, the solar cell is placed in a UV (ultraviolet light) box with a UV irradiance of 180 W / m 2 After cumulative irradiation with UV30 under the conditions of 5.6% of UVB, the on-state voltage decay of the photoelectric conversion efficiency of the solar cell was 0.8%, which was much lower than the on-state voltage decay value of 2.1% of the control group (single N-type crystalline silicon cell, single perovskite cell, etc.).

[0053] According to the technical solution in the embodiment of the present invention, the preparation method first provides an N-type silicon substrate, and performs boron diffusion doping treatment on one side of the first surface of the N-type silicon substrate, and performs phosphorus diffusion doping treatment on one side of the second surface of the N-type silicon substrate; wherein the first surface and the second surface are two surfaces of the N-type silicon substrate that are opposite to each other, and the first surface is a velvet surface, and the second surface is a polished surface, and then a first passivation film layer is formed on the first surface, and a second passivation film layer is formed on the second surface, and then a laser groove is performed on one side of the second passivation film layer, and a perovskite stacked structure is formed in the formed groove area; wherein the perovskite stacked structure includes a first conductive layer, a hole transport layer, a perovskite layer, an electron transport layer, a conductive transition layer and a second conductive layer stacked in sequence, and the first conductive layer is in contact with the second surface, and finally screen printing and sintering treatment are performed on one side of the first passivation film layer and / or one side of the second passivation film layer to form an electrode structure to obtain a solar cell. By using the above method, a first surface side of the N-type silicon substrate is subjected to boron diffusion doping treatment, a second surface side of the N-type silicon substrate is subjected to phosphorus diffusion doping treatment, and a passivation film layer is formed on both sides of the N-type silicon substrate, which effectively increases the passivation and anti-ultraviolet attenuation performance of both sides of the N-type silicon substrate, and a perovskite stacked structure is superimposed on the back side of the N-type silicon substrate. The superposition of the two achieves a higher photoelectric conversion efficiency of the overall solar cell, so that the prepared solar cell can effectively take into account both high photoelectric conversion efficiency and high reliability, and the perovskite stacked structure is formed in the groove area of ​​the laser groove, which can further reduce the influence of ultraviolet and infrared on the perovskite cell.

[0054] Optionally, before performing phosphorus diffusion doping treatment on one side of the second surface of the N-type silicon substrate, the method further includes: sequentially forming a tunneling oxide layer and a polysilicon layer on the second surface.

[0055] Specifically, the tunneling oxide layer and the polysilicon layer are used to allow the majority carriers (electrons) to pass smoothly through the tunneling effect, while preventing the recombination of minority carriers (holes) to achieve selective collection of carriers, reduce surface recombination, and increase the open circuit voltage and fill factor of the battery, thereby improving the photoelectric conversion efficiency of the overall solar cell. The composite layer of the tunneling oxide layer and the polysilicon layer together forms a passivation contact structure, which can effectively reduce the surface recombination and metal contact recombination of the overall solar cell. In other words, depositing an ultra-thin tunneling oxide layer on the second surface of the N-type silicon substrate can provide good interface passivation and provide different carrier tunneling barriers. Depositing a polysilicon layer on the tunneling oxide layer can increase the migration rate of electrons and suppress the migration rate of holes. In addition, the polysilicon layer contacts the subsequent metal electrode and acts as an electron transmission bridge. In a specific embodiment, during the laser grooving process, the second passivation film layer of the corresponding groove area can be removed without destroying the polysilicon layer, so as to facilitate the contact between the subsequent perovskite stacked structure and the polysilicon layer. For example, low pressure chemical vapor deposition (LPCVD) technology can be used to first prepare an ultra-thin silicon dioxide layer on the second surface of the N-type silicon substrate as the above-mentioned tunneling oxide layer, and then deposit a polycrystalline silicon thin layer on the ultra-thin silicon dioxide layer to form a polycrystalline silicon layer that meets the passivation effect.

[0056] Figure 2 1 is a schematic flow chart of another method for preparing a solar cell provided by an embodiment of the present invention. This embodiment is optimized on the basis of the above embodiment. Optionally, the first passivation film layer includes an anti-ultraviolet attenuation film layer and a first anti-reflection layer; the second passivation film layer includes a second anti-reflection layer;

[0057] Forming a first passivation film layer on the first surface, and forming a second passivation film layer on the second surface, comprising:

[0058] forming an anti-ultraviolet attenuation film layer on the first surface;

[0059] forming a first anti-reflection layer on a side of the anti-ultraviolet attenuation film layer away from the first surface;

[0060] A second anti-reflection layer is formed on the second surface.

[0061] For details not yet provided in this embodiment, please refer to the above embodiments. Figure 2 As shown, the preparation method comprises:

[0062] S210, providing an N-type silicon substrate, and performing a boron diffusion doping treatment on one side of a first surface of the N-type silicon substrate, and performing a phosphorus diffusion doping treatment on one side of a second surface of the N-type silicon substrate; wherein the first surface and the second surface are two surfaces of the N-type silicon substrate that are opposite to each other, and the first surface is a velvet surface, and the second surface is a polished surface.

[0063] S220, forming an anti-ultraviolet attenuation film layer on the first surface.

[0064] Specifically, the first passivation film layer includes an anti-ultraviolet attenuation film layer and a first anti-reflection layer. Exemplarily, an anti-ultraviolet attenuation film layer can be formed on the first surface of the N-type silicon substrate by atomic layer deposition (ALD) technology and a water process. Exemplarily, the temperature of the ALD process can be 200-300°C and the deposition time can be 8-10min. The deposition can be cyclically deposited 20 times under the conditions of a TMA flow rate of 1500sccm, an oxygen flow rate of 1800sccm, and a temperature of 278°C, and the deposition time can be 6min. Optionally, the material of the anti-ultraviolet attenuation film layer includes aluminum oxide. Optionally, the thickness of the anti-ultraviolet attenuation film layer ranges from 6-10nm. Exemplarily, the thickness of the anti-ultraviolet attenuation film layer can be 8nm, which can effectively play the role of anti-ultraviolet attenuation and passivation of the front side of the N-type silicon substrate. It can be understood that this embodiment effectively increases the anti-ultraviolet ability of the overall solar cell by reasonably increasing the thickness of the anti-ultraviolet attenuation film layer.

[0065] S230, forming a first anti-reflection layer on a side of the anti-ultraviolet attenuation film layer away from the first surface.

[0066] Specifically, a coating process and a high refractive index process can be used to form a first anti-reflection layer on the side of the anti-ultraviolet attenuation film layer away from the first surface. The first anti-reflection layer can further improve the passivation and anti-ultraviolet attenuation performance of the overall solar cell, and can also reduce the reflection of sunlight, increase the absorption of sunlight, and improve the photoelectric conversion efficiency of the overall solar cell. At the same time, it reduces surface recombination, increases the mobility of carriers, and improves the overall performance of the overall solar cell. Optionally, the material of the first anti-reflection layer includes silicon nitride. Optionally, the refractive index of the first anti-reflection layer ranges from 2.2% to 2.3%. This embodiment effectively increases the anti-ultraviolet ability of the overall solar cell by reasonably increasing the refractive index of the first anti-reflection layer.

[0067] S240, forming a second anti-reflection layer on the second surface.

[0068] Specifically, the second passivation film layer includes a second anti-reflection layer. A second anti-reflection layer can be formed on the second surface of the N-type silicon substrate by using a coating process and a high refractive index process. The second anti-reflection layer can further enhance the passivation and anti-ultraviolet attenuation performance of the overall solar cell. Optionally, the material of the second anti-reflection layer includes silicon nitride. Optionally, the refractive index range of the second anti-reflection layer is 2.2%-2.3%. This embodiment effectively increases the anti-ultraviolet capability of the overall solar cell by reasonably increasing the refractive index of the second anti-reflection layer. In addition, the first anti-reflection layer and the second anti-reflection layer can be understood as being prepared at the same time. The first anti-reflection layer and the second anti-reflection layer are only different in position, and the rest of the materials, parameters, etc. are the same.

[0069] S250. Performing laser grooving on one side of the second passivation film layer, and forming a perovskite stacked structure in the formed groove area; wherein the perovskite stacked structure includes a first conductive layer, a hole transport layer, a perovskite layer, an electron transport layer, a conductive transition layer and a second conductive layer stacked in sequence, and the first conductive layer is in contact with the second surface.

[0070] S260, performing screen printing and sintering treatment on one side of the first passivation film layer and / or one side of the second passivation film layer to form an electrode structure to manufacture a solar cell.

[0071] Based on the same inventive concept, an embodiment of the present invention further provides a solar cell. The solar cell is prepared by a method for preparing a solar cell provided in any one of the embodiments of the present invention. Therefore, the solar cell has functional modules and beneficial effects corresponding to the method for preparing a solar cell.

[0072] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for preparing a solar cell, characterized in that: include: Providing an N-type silicon substrate, and performing a boron diffusion doping treatment on one side of a first surface of the N-type silicon substrate, and performing a phosphorus diffusion doping treatment on one side of a second surface of the N-type silicon substrate; wherein the first surface and the second surface are two surfaces of the N-type silicon substrate that are opposite to each other, and the first surface is a velvet surface, and the second surface is a polished surface; forming a first passivation film layer on the first surface, and forming a second passivation film layer on the second surface; A laser groove process is performed on one side of the second passivation film layer, and a perovskite stacked structure is formed in the formed groove area; wherein the perovskite stacked structure includes a first conductive layer, a hole transport layer, a perovskite layer, an electron transport layer, a conductive transition layer and a second conductive layer stacked in sequence, and the first conductive layer is in contact with the second surface; Screen printing and sintering are performed on one side of the first passivation film layer and / or one side of the second passivation film layer to form an electrode structure to manufacture the solar cell.

2. The preparation method according to claim 1, characterized in that: The material of the first conductive layer includes indium oxide; and / or, the material of the hole transport layer includes nickel oxide and PVK; and / or, the material of the perovskite layer includes CH3NH3PbCl3; and / or, the material of the electron transport layer includes C60; and / or, the material of the conductive transition layer includes zinc oxide; and / or, the material of the second conductive layer includes indium oxide.

3. The preparation method according to claim 1, characterized in that: The thickness range of the first conductive layer is 110-130nm; and / or, the thickness range of the hole transport layer is 35-55nm; and / or, the thickness range of the perovskite layer is 340-360nm; and / or, the thickness range of the electron transport layer is 20-40nm; and / or, the thickness range of the conductive transition layer is 50-100nm; and / or, the thickness range of the second conductive layer is 270-290nm.

4. The preparation method according to claim 1, characterized in that: The first passivation film layer includes an anti-ultraviolet attenuation film layer and a first anti-reflection layer; the second passivation film layer includes a second anti-reflection layer; Forming a first passivation film layer on the first surface, and forming a second passivation film layer on the second surface, comprising: forming the anti-ultraviolet attenuation film layer on the first surface; forming the first anti-reflection layer on a side of the anti-ultraviolet attenuation film layer away from the first surface; The second anti-reflection layer is formed on the second surface.

5. The preparation method according to claim 4, characterized in that: The thickness of the anti-ultraviolet attenuation film layer is in the range of 6-10 nm.

6. The preparation method according to claim 4, characterized in that: The refractive index of the first anti-reflection layer is in the range of 2.2%-2.3%; and / or the refractive index of the second anti-reflection layer is in the range of 2.2%-2.3%.

7. The preparation method according to claim 4, characterized in that: The material of the anti-ultraviolet attenuation film layer includes aluminum oxide; and / or the material of the first anti-reflection layer includes silicon nitride; and / or the material of the second anti-reflection layer includes silicon nitride.

8. The preparation method according to claim 1, characterized in that: Before performing phosphorus diffusion doping treatment on one side of the second surface of the N-type silicon substrate, the method further includes: A tunneling oxide layer and a polysilicon layer are sequentially formed on the second surface.

9. The preparation method according to claim 1, characterized in that: The reflectivity of the suede surface of the first surface is in the range of 8%-9%.

10. A solar cell, characterized in that: The solar cell is prepared by the method for preparing the solar cell according to any one of claims 1 to 9.

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