Solar cell, preparation method thereof and photovoltaic module

Abstract

The invention relates to the technical field of photovoltaic cells, in particular to a solar cell, a preparation method thereof and a photovoltaic module. The solar cell comprises a substrate, a first charge transport layer, a perovskite active layer, a second charge transport layer, an adsorption layer and a transparent conductive oxide layer which are stacked in sequence, wherein the adsorption layer comprises a metal oxide material, and the metal oxide material has a nano-porous structure. The metal oxide material with the nano-porous structure in the adsorption layer effectively improves the adhesive force between the transparent conductive oxide layer and the laminated structure below the transparent conductive oxide layer through a synergistic effect mechanism of combining physical adsorption and chemical adsorption, thereby improving the stability and reliability of the solar cell, prolonging the service life of the cell, and improving the reliability of the solar cell. And good electrical properties and structural integrity of the battery can be kept in a long-term operation process.

Description

TECHNICAL FIELD

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

[0002] Perovskite solar cells have attracted extensive attention due to their long carrier diffusion length, high light absorption coefficient, adjustable band gap, compatibility with various preparation methods, and simple preparation method.

[0003] In the prior art, the transparent conductive oxide (TCO) layer on the top of the solar cell is usually deposited by a magnetron sputtering process. The magnetron sputtering process is a physical vapor deposition process, which generates sputtering by bombarding the target material with high-energy plasma, so that the target atoms or molecules migrate and deposit on the surface of the underlying layer structure, thereby forming a TCO film with good conductivity and high transmittance.

[0004] However, in the process of magnetron sputtering, the sputtering particles have high kinetic energy and a fast deposition rate, and the film formation relies on physical adsorption, lacking strong chemical bond interaction, which makes the interaction between the prepared TCO layer and the underlying layer structure weak, and the interfacial bonding force insufficient, resulting in easy separation of the interface during the operation of the cell, affecting the device performance and service life of the solar cell. SUMMARY

[0005] Therefore, it is necessary to provide a solar cell, a preparation method thereof and a photovoltaic module to improve the adhesion between the transparent conductive oxide layer on the top of the solar cell and the underlying layer structure, thereby improving the stability and reliability of the solar cell, prolonging the service life of the cell, and ensuring that the cell can maintain good electrical performance and structural integrity during long-term operation.

[0006] In a first aspect, the present application provides a solar cell, which comprises a substrate, a first charge transport layer, a perovskite active layer, a second charge transport layer, an adsorption layer and a transparent conductive oxide layer which are sequentially stacked; wherein the adsorption layer comprises a metal oxide material, and the metal oxide material has a nano-porous structure.

[0007] In some embodiments, the solar cell further comprises a buffer layer, which is stacked between the second charge transport layer and the adsorption layer, and the buffer layer comprises a tin oxide material.

[0008] In some embodiments, the thickness of the adsorption layer is 1 nm to 50 nm.

[0009] In some embodiments, the metal oxide material comprises at least one of zinc oxide, titanium dioxide, tungsten trioxide, nickel oxide, tricobalt tetraoxide, cuprous oxide, zirconium dioxide, niobium pentoxide, and zinc stannate.

[0010] In some embodiments, the metal oxide material has a pore size of 1 nm to 40 nm.

[0011] In some embodiments, the metal oxide material has a specific surface area of 1 m 2 / g to 200 m 2 / g.

[0012] In some embodiments, the substrate is a crystalline silicon cell, and the solar cell further comprises a tunneling recombination layer, which is disposed between the crystalline silicon cell and the first charge transport layer.

[0013] In a second aspect of the present application, a method for preparing a solar cell is provided, which comprises the following steps: sequentially forming a first charge transport layer, a perovskite active layer, and a second charge transport layer on a substrate to prepare a stacked structure; forming an adsorption layer on a side of the stacked structure away from the substrate, the adsorption layer comprising a metal oxide material, and the metal oxide material having a nanoporous structure; and forming a transparent conductive oxide layer on the adsorption layer by a magnetron sputtering process to prepare the solar cell.

[0014] In some embodiments, the step of forming the adsorption layer on the side of the stacked structure away from the substrate specifically comprises the following steps: dispersing the metal oxide material in a solvent to prepare a precursor solution; and depositing the precursor solution on the side of the stacked structure away from the substrate to form the adsorption layer, wherein the deposition is performed by at least one of spin coating, spray coating, inkjet printing, blade coating, slot coating, or soaking.

[0015] In some embodiments, the metal oxide material has a mass percentage of 1% to 40% in the precursor solution.

[0016] In some embodiments, the solvent is at least one of ethylene glycol methyl ether, isopropyl alcohol, ethanol, and toluene.

[0017] In some embodiments, after the preparation of the precursor solution, the method further comprises the following step: dispersing the precursor solution by oscillation and / or heating.

[0018] In some embodiments, the stacked structure further comprises a buffer layer, and the buffer layer is formed on a surface of the second charge transport layer by an atomic layer deposition process, and the buffer layer comprises a tin oxide material.

[0019] In a third aspect of the present application, a photovoltaic module is provided, which comprises the solar cell provided in the first aspect or prepared by the method provided in the second aspect.

[0020] Compared with the prior art, the solar cell provided by some embodiments of the present application has at least the following beneficial effects: the adsorption layer of the solar cell is made of a metal oxide material with a nano-porous structure. On the one hand, the nano-porous structure provides a large number of anchoring sites for the transparent conductive oxide layer formed subsequently. In the process of magnetron sputtering, the sputtering particles of the transparent conductive oxide material can penetrate into the pore structure, forming a close and firm physical interlocking effect, thereby significantly enhancing the interfacial bonding force between the transparent conductive oxide layer and the underlying layer structure. On the other hand, the metal oxide surface is rich in active groups such as hydroxyl groups, which can chemically bond with the transparent conductive oxide material, further enhancing the interfacial force between the transparent conductive oxide layer and the underlying layer structure. In this way, the adsorption layer effectively improves the adhesion between the transparent conductive oxide layer and the underlying layer structure through the synergistic mechanism of the above-mentioned physical and chemical adsorption, thereby improving the stability and reliability of the solar cell, prolonging the service life of the cell, and ensuring that the cell can maintain good electrical performance and structural integrity during long-term operation. BRIEF DESCRIPTION OF DRAWINGS

[0021] For better describing and illustrating the embodiments or examples provided by the present application, one or more drawings can be referred to. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any one of the disclosed applications, the presently described embodiments or examples, and the best mode presently understood of these applications. Moreover, the same reference numbers are used throughout the drawings to represent the same components. In the drawings:

[0022] Figure 1 FIG. 1 is a structural schematic diagram of a solar cell in an embodiment of the present application.

[0023] Figure 2 FIG. 2 is a flowchart of a preparation method of a solar cell in an embodiment of the present application.

[0024] LIST OF REFERENCE NUMERALS

[0025] 1. Solar cell; 10, substrate; 20, tunneling recombination layer; 30, first charge transport layer; 40, perovskite active layer; 50, second charge transport layer; 60, buffer layer; 70, adsorption layer; 80, transparent conductive oxide layer; 90, metal electrode layer. DETAILED DESCRIPTION

[0026] Reference will now be made in detail to the embodiments of the application, one or more examples of which are described hereinbelow. Each example is provided by way of explanation of the application, not limitation of the application. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the scope or spirit of the application. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present application cover modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

[0027] It is therefore intended that the application cover all such modifications and variations of this application as come within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present application are disclosed in or are apparent from the following detailed description of the application. It is to be understood by the skilled artisan that the discussion herein is a description of exemplary embodiments only, and is not intended as limiting on the broader aspects of the present application.

[0028] In the present application, the technical features described in an open way include both the closed technical solution consisting of the listed features and the open technical solution containing the listed features.

[0029] In the present application, when referring to a numerical interval, unless otherwise specified, the numerical interval is considered to be continuous and includes the minimum and maximum values of the range and every value between the minimum and maximum values. Further, when the range refers to integers, every integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe a feature or a characteristic, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein are to be understood to include any and all sub-ranges subsumed therein.

[0030] If not specifically mentioned, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.

[0031] If not specifically mentioned, all technical features and optional technical features of the present application can be combined with each other to form new technical solutions.

[0032] If not specifically mentioned, all steps of the present application can be performed in sequence or randomly, and preferably in sequence. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, it is mentioned that the method can further comprise step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0033] If not specifically stated, the "comprising" and "including" mentioned in the present application represent open-ended, and can also be closed-ended. For example, the "comprising" and "including" can represent that other components not listed can also be included, or only the listed components can be included.

[0034] In combination Figure 1 As shown, in the first aspect of the present application, a solar cell 1 is provided, which comprises a substrate 10, a first charge transport layer 30, a perovskite active layer 40, a second charge transport layer 50, an adsorption layer 70 and a transparent conductive oxide layer 80 which are sequentially stacked. The adsorption layer 70 comprises a metal oxide material, and the metal oxide material has a nanoporous structure.

[0035] The solar cell 1 provided by the present application uses a metal oxide material with a nanoporous structure for the adsorption layer 70. On the one hand, the nanoporous structure provides a large number of anchoring sites for the transparent conductive oxide layer 80 formed on the top of the solar cell 1, and in the process of magnetron sputtering, the sputtered particles of the transparent conductive oxide material can penetrate into the pore structure, forming a tight and firm physical bonding effect, thereby significantly enhancing the interfacial bonding force between the transparent conductive oxide layer 80 and the underlying stacked structure. On the other hand, the metal oxide surface is rich in active groups such as hydroxyl groups, which can chemically bond with the transparent conductive oxide material, further enhancing the interfacial force between the transparent conductive oxide layer 80 and the underlying stacked structure. Thus, through the synergistic mechanism of physical and chemical adsorption of the adsorption layer 70, the adhesion between the transparent conductive oxide layer 80 and the underlying stacked structure is effectively improved, thereby improving the stability and reliability of the solar cell 1, prolonging the service life of the cell, and ensuring that the cell can maintain good electrical performance and structural integrity during long-term operation.

[0036] It can be understood that the metal oxide material in the adsorption layer 70 has the following advantages: (1) the nano-porous structure in the metal oxide material makes the metal oxide material have a large specific surface area and a large number of nano-scale pores, which can serve as anchor points to deeply adsorb the transparent conductive oxide material; (2) the metal oxide material itself is relatively stable at normal temperature and pressure, and is not easy to chemically react with other substances, and can maintain its own structure and performance for a long time, so the adsorption layer 70 can still exist stably under the influence of the complex environment of the operation of the solar cell 1, such as water vapor, oxygen, and ion migration of perovskite material; (3) the metal oxide material itself has high transparency and does not cause excessive parasitic absorption, and can be doped with other metals or non-metals or compounded with other materials to adjust the energy level, thereby forming an efficient electron transport channel, promoting the rapid transfer of electrons from the perovskite active layer 40 to the transparent conductive oxide layer, reducing the electron-hole recombination probability, and improving the open-circuit voltage and short-circuit current of the cell.

[0037] In this document, "top" refers to the light-receiving side of the solar cell 1 that allows light to enter; correspondingly, "lower layer structure" refers to the layer structure disposed below the transparent conductive oxide layer 80, away from the light-receiving direction.

[0038] In some embodiments, the solar cell 1 further includes a metal electrode layer 90. The material of the metal electrode layer 90 includes at least one of Ag, Cu, Al, and Au; the metal electrode layer 90 functions to transmit charges to an external circuit.

[0039] According to some embodiments of the present application, the first charge transport layer 30 can be a hole transport layer, and thus the subsequently formed second charge transport layer 50 is an electron transport layer; according to some embodiments of the present application, the first charge transport layer 30 is an electron transport layer, and thus the subsequently formed second charge transport layer 50 is a hole transport layer.

[0040] Materials of the hole transport layer include at least one of [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz), (2-(3,6-dimethyl-9H-carbazol-9-yl)ethyl)phosphonic acid (Me-2PACz), [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz), [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (4PACz), [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz), [4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid (MeO-4PACz), 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene (spiro-OMeTAD), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS), 2,2',7,7'-tetrakis(di-p-tolylamino)spiro-9,9'-bifluorene (spiro-TTB), and nickel oxide (NiO x The hole transport layer functions to collect holes from the perovskite active layer 40 and to block the transport of electrons.

[0041] Materials of the electron transport layer include at least one of C 60 and a fullerene derivative, specifically [6,6]-phenyl-C61-butyric acid methyl ester and [6,6]-phenyl-C71-butyric acid methyl ester (PCBM); the electron transport layer functions to collect electrons from the perovskite active layer 40 and to block the transport of holes.

[0042] Materials of the perovskite active layer 40 include (FA x Cs y MA z )Pb(Cl p Br q I r )3, where x+y+z=1, p+q+r=1, consisting of at least two of FAI, FABr, MAI, MABr, PbI2, PbBr2, PbCl2, with a band gap of 1.48-1.80 eV; the perovskite active layer 40 functions to absorb short-wavelength sunlight and to generate photo-generated electron-hole pairs.

[0043] The material of the transparent conductive oxide layer 80 includes at least one of indium tin oxide (ITO), indium zinc oxide (IZO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), tungsten-doped indium oxide (IWO), and indium zirconium oxide (IZrO), and is prepared by a magnetron sputtering method. The transparent conductive oxide layer 80 functions to collect the charge and transmit the charge laterally to the metal electrode layer 90.

[0044] In some embodiments, the solar cell 1 further includes a buffer layer 60, which is arranged between the second charge transport layer 50 and the adsorption layer 70.

[0045] The material of the buffer layer 60 includes at least one of tin oxide (SnO x ) and bathocuproin (BCP). The buffer layer 60 functions to improve the contact between the second charge transport layer 50 and the transparent conductive oxide layer 80 and avoid damage to the second charge transport layer 50 during preparation of the transparent conductive oxide layer 80.

[0046] Further, the buffer layer 60 includes a tin oxide material. In this way, the hydroxyl groups and other groups on the surface of the metal oxide material in the adsorption layer 70 can be chemically bonded to the SnO x material in the buffer layer 60 and the TCO material in the transparent conductive oxide layer 80, thereby achieving super strong adhesion and closely combining with the materials of the upper and lower layers, and significantly improving the interface adhesion performance.

[0047] In some embodiments, the thickness of the adsorption layer 70 is 1 nm to 50 nm. For example, the thickness of the adsorption layer 70 can be, but is not limited to, 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, or 50 nm. Within the above thickness range, sufficient active sites and adsorption capacity can be provided, while preventing additional parasitic absorption of the carriers during transmission. For example, when the thickness of the adsorption layer 70 is too large, the path length of the electron or hole transport is increased, which increases the recombination probability of the carriers during transmission and also increases the additional parasitic absorption, which is not conducive to the performance of the device. When the thickness of the adsorption layer 70 is too small, a continuous and complete film cannot be formed, and sufficient active sites and adsorption capacity cannot be provided, which results in insufficient interface adhesion in local areas and cannot effectively solve the problem of peeling of the transparent conductive oxide layer 80.

[0048] In some embodiments, the metal oxide material includes at least one of zinc oxide, titanium dioxide, tungsten trioxide, nickel oxide, tricobalt tetraoxide, cuprous oxide, zirconium dioxide, niobium pentoxide, and zinc stannate. In this way, the metal oxide material is selected from the above materials, which have the following advantages: (1) the above materials have high carrier mobility, which can reduce the probability of carrier recombination during transmission; (2) the work function of the above materials is close to that of the transparent conductive oxide material, which can form a good ohmic contact with the transparent conductive oxide, reduce the contact resistance, and ensure that the carriers can be efficiently injected into the transparent conductive oxide layer 80; (3) the above materials have high transmittance in the visible light region, which can reduce the absorption loss of light in the adsorption layer 70 and the transparent conductive oxide layer 80, and ensure that more photons can reach the perovskite active layer 40; (4) the above materials are chemically stable at normal temperature and pressure, and are not prone to chemical reactions with other substances. Even in complex environments such as high temperature, high humidity, and light, the materials can maintain the basic stability of their structure and performance; (5) the above materials maintain structural and performance stability in a wide temperature range, and are not prone to performance degradation or failure due to temperature changes, which is important for ensuring the stable operation of the device in different working environments; (6) the above materials have high hardness and mechanical strength, which can provide mechanical support and protection for the transparent conductive oxide layer 80 and the perovskite active layer 40, and reduce the damage of external mechanical stress to the internal structure of the device; (7) the raw materials of the above materials are widely available, and the cost is relatively low. Moreover, most of the above materials can be prepared by solution method, which is simple and easy to operate, and is suitable for the existing perovskite battery production line.

[0049] In some embodiments, the pore size of the metal oxide material is 1 nm to 40 nm. For example, the pore size of the metal oxide material can be, but is not limited to, 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, or 40 nm. Within the above pore size range, the sputtered particles of the transparent conductive oxide material can be anchored and adsorbed to provide sufficient anchoring points, form a dense and firm physical bite effect, and help maintain the continuity of the adsorption layer 70 and improve the stability of the device.

[0050] In some embodiments, the specific surface area of the metal oxide material is 1 m 2 / g to 200 m 2 / g. For example, the specific surface area of the metal oxide material can be, but is not limited to, 1 m 2 / g, 25 m 2 / g, 50 m 2 / g, 75 m 2 / g, 100 m 2 / g, 125 m 2 / g, 150 m2 / g、175 m 2 / g、200 m 2 / g. Within the above specific surface area range, it can provide sufficient anchor points to adsorb sputtered particles of transparent conductive oxide materials, forming a dense and strong physical interlocking effect, and also helps to maintain the continuity of the adsorption layer 70 and improve the stability of the device.

[0051] In some embodiments, the substrate 10 is a crystalline silicon cell, and the solar cell 1 further includes a tunneling composite layer 20, which is stacked between the crystalline silicon cell and the first charge transport layer 30.

[0052] The crystalline silicon cell is selected from any one of the following: passivated emitter and back contact cell (PERC), tunneling oxide passivated contact solar cell (TOPCon), heterojunction cell (HJT), interdigitated back contact cell (IBC), heterojunction back contact cell (HBC), and tunneling oxide passivated back contact cell (TBC). When the crystalline silicon cell is used as substrate 10, the solar cell 1 is a tandem cell, and the crystalline silicon cell is used as the bottom cell of the tandem cell to absorb long-wavelength sunlight.

[0053] The material of the tunneling composite layer 20 includes at least one of indium tin oxide (ITO), indium zinc oxide (IZO), tungsten-doped indium oxide (IWO), and indium zirconium oxide (IZrO); the function of the tunneling composite layer 20 is to recombine electrons and holes from the bottom cell and the hole transport layer.

[0054] In some embodiments, the substrate 10 is conductive glass. Exemplarily, the conductive glass may be FTO conductive glass or ITO conductive glass.

[0055] A second aspect of this application provides a method for preparing a solar cell, such as... Figure 2 As shown, the fabrication method includes the following steps: S1, forming a first charge transport layer, a perovskite active layer, and a second charge transport layer sequentially on a substrate to prepare a stacked structure. S2, forming an adsorption layer on the side of the stacked structure away from the substrate, the adsorption layer comprising a metal oxide material having a nanoporous structure. S3, forming a transparent conductive oxide layer on the adsorption layer using a magnetron sputtering process to fabricate a solar cell.

[0056] The preparation method of the solar cell provided in the application, in step S2, the adsorption layer including the metal oxide material with the nano-porous structure is formed on the laminated structure, which significantly improves the interface bonding performance between the transparent conductive oxide layer deposited subsequently and the laminated structure below. Specifically, the nano-porous structure of the metal oxide material provides abundant physical anchoring sites for the deposition process of the transparent conductive oxide material, so that the TCO material can be embedded into the pores to form physical occlusion in the subsequent deposition process; meanwhile, the surface of the metal oxide material is rich in active groups such as hydroxyl groups, which can be chemically bonded with the transparent conductive oxide material to enhance the interface force. In this way, the adsorption layer effectively improves the adhesion between the transparent conductive oxide layer and the laminated structure below through the synergistic mechanism of the above-mentioned physical adsorption and chemical adsorption, thereby improving the stability and reliability of the solar cell, prolonging the service life of the cell, and ensuring that the cell can maintain good electrical performance and structural integrity during long-term operation. In step S3, the transparent conductive oxide layer is deposited and prepared by using a magnetron sputtering process, and the high-energy sputtering particles can penetrate into the pore structure of the metal oxide material during the deposition process, and form a stable physical occlusion effect with the adsorption layer structure, thereby further enhancing the interface adhesion and film formation stability. The process cooperates with the adsorption layer structure constructed in step S2, which significantly improves the interface bonding force between the transparent conductive oxide layer and the laminated structure below. In addition, the above-mentioned preparation method is simple in process, easy to operate, compatible with the current solar cell preparation process, and has good industrial application prospects.

[0057] In some embodiments, in step S1, the first charge transport layer and the second charge transport layer can be prepared by at least one of spin coating, spraying, inkjet printing, blade coating, slot coating, evaporation, and immersion; and the perovskite active layer can be prepared by at least one of spin coating, spraying, inkjet printing, blade coating, slot coating, evaporation, and immersion.

[0058] In some embodiments, in step S2, the method specifically includes the following steps: S21, dispersing the metal oxide material in a solvent to prepare a precursor solution; S22, depositing the precursor solution on the side of the laminated structure away from the substrate to form an adsorption layer; and the deposition method includes at least one of spin coating, spraying, inkjet printing, blade coating, slot coating, or immersion.

[0059] In this way, the adsorption layer is prepared by a solution method, which is simple in process, easy to operate, and suitable for the current solar cell production line.

[0060] Further, the precursor solution is deposited on the side of the stacked structure away from the substrate by spin coating. Specifically, the following steps are included: S221, dropping the precursor solution on the side of the stacked structure away from the substrate, and forming a film by high-speed rotation of a film applicator. S222, after spin coating, annealing on a heating table to remove residual solvent and form an adsorption layer.

[0061] In some embodiments, in step S221, the rotation speed ranges from 1000 rpm to 5000 rpm, and the time ranges from 10 s to 50 s.

[0062] In some embodiments, in step S221, the annealing temperature ranges from 50-200 °C, and the time ranges from 1-100 min, preferably 100 °C for 60 min.

[0063] In some embodiments, the mass percentage of the metal oxide material in the precursor solution ranges from 1% to 40%. For example, the mass percentage of the metal oxide material in the precursor solution can be, but is not limited to, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40%.

[0064] In some embodiments, the solvent is selected from at least one of ethylene glycol methyl ether, isopropyl alcohol, ethanol, and toluene.

[0065] Ethylene glycol methyl ether has good solubility, can effectively disperse the precursor of the metal oxide, and makes the precursor uniformly distributed in the solution, which is conducive to the formation of a uniform film. At the same time, ethylene glycol methyl ether has moderate volatility, which is convenient for controlling the film formation process.

[0066] Isopropyl alcohol has moderate surface tension, which is helpful for forming a uniform film in the spin coating process. At the same time, isopropyl alcohol has low cost and is easy to obtain, which is suitable for large-scale production and can effectively reduce the preparation cost.

[0067] Ethanol is non-toxic or low-toxic, has good environmental protection, and has less harm to the environment and personnel during use. Ethanol has fast volatility, can quickly form a film, shorten the preparation time, and improve the production efficiency.

[0068] Toluene has strong solubility, can dissolve various metal oxide precursors, and makes the precursors have good dispersibility and stability in the solution, which is helpful for forming a uniform film in the spin coating process and improving the quality and performance of the film.

[0069] In some embodiments, after step S21, the preparation method further includes the following step: dispersing the precursor solution by oscillation and / or heating.

[0070] In some embodiments, the stacked structure further includes a buffer layer formed on the surface of the second charge transport layer by an atomic layer deposition process, the buffer layer comprising tin oxide material.

[0071] In traditional techniques, atomic layer deposition (ALD) is used to prepare tin oxide buffer layers. This technique enables the growth of thin films with atomic precision, resulting in uniform and dense tin oxide films. The buffer layers prepared in this way exhibit good electron transport and energy level matching properties. However, the interfacial adhesion between the tin oxide film prepared by ALD and the upper transparent conductive oxide layer is relatively weak. This poses a risk of interfacial delamination during long-term device operation, thereby affecting device performance and lifespan.

[0072] Therefore, in the embodiments of this application, an adsorption layer is prepared on the surface of the buffer layer, and the hydroxyl groups and other groups abundant on the surface of the metal oxide material in the adsorption layer can simultaneously react with the SnO in the buffer layer. x It chemically bonds with the TCO material in the transparent conductive oxide layer, thereby achieving super strong adhesion, which improves the stability and reliability of the solar cell, extends the service life of the cell, and ensures that the cell can maintain good electrical performance and structural integrity during long-term operation.

[0073] In some specific embodiments, the buffer layer can be prepared using at least one of spin coating, spray coating, inkjet printing, blade coating, slot coating, vapor deposition, immersion, and atomic layer deposition.

[0074] In some embodiments, the substrate is a crystalline silicon cell, and step S1 further includes the following step: preparing a tunneling composite layer between the substrate and the first charge transport layer.

[0075] In some specific embodiments, the tunneling composite layer can be prepared using at least one of magnetron sputtering, pulsed laser deposition, chemical vapor deposition, atomic layer deposition, and plasma deposition.

[0076] In some embodiments, after step S3, the following step is also included: S4, forming a metal electrode layer on the surface of the transparent conductive oxide layer.

[0077] In some specific embodiments, the metal electrode layer can be prepared by at least one of screen printing, electroplating, inkjet printing, and vapor deposition.

[0078] A third aspect of this application provides a photovoltaic module, which includes the solar cell provided in the first aspect above, or the solar cell prepared by the method for preparing the solar cell provided in the second aspect above.

[0079] Multiple solar cells can be arranged, and they can be electrically connected in a single unit or in multiple segments to form multiple cell strings. These cell strings can be connected in series and / or parallel. The photovoltaic module may also include an encapsulation layer and a cover plate. The encapsulation layer covers the surface of the cell strings, and the cover plate covers the surface of the encapsulation layer away from the cell strings. Specifically, in some embodiments, multiple cell strings can be electrically connected through conductive means. The encapsulation layer covers the surface of the solar cells. Exemplarily, the encapsulation layer can be an organic encapsulation film such as an ethylene-vinyl acetate copolymer film, a polyethylene octene co-elastomer film, or a polyethylene terephthalate film. The cover plate can be a glass cover plate, a plastic cover plate, or other light-transmitting cover plate.

[0080] Based on the same inventive concept, embodiments of this application provide a photovoltaic system, including the photovoltaic modules in any of the above embodiments.

[0081] It is understandable that photovoltaic (PV) systems can be applied to PV power plants, such as ground-mounted, rooftop, and floating power plants, as well as to equipment or devices that utilize solar energy for power generation, such as user-installed solar power supplies, solar streetlights, solar-powered cars, and solar-powered buildings. Of course, it is also understandable that the application scenarios of PV systems are not limited to these; that is, PV systems can be applied in all areas that require solar energy for power generation. Taking a PV power grid as an example, a PV system can include PV arrays, combiner boxes, and inverters. A PV array can be a combination of multiple PV modules; for example, multiple PV modules can form multiple PV arrays. The PV arrays are connected to combiner boxes, which collect the current generated by the PV arrays. The collected current then flows through an inverter, converting it into AC power required by the mains grid before being connected to the mains grid to achieve solar power supply.

[0082] The present application will be further described below with reference to specific embodiments and comparative examples.

[0083] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0084] Example 1

[0085] This embodiment provides a method for preparing a solar cell.

[0086] (1) An ITO tunneling composite layer with a thickness of 15 nm was prepared on a heterojunction bottom battery substrate by magnetron sputtering. The magnetron sputtering process adopted DC sputtering mode, the target material was In2O3:SnO2 (95wt%:5wt%), and the sputtering power was 80W.

[0087] (2) A Me-4PACz hole transport layer with a thickness of 2 nm was prepared on the tunneling composite layer by spin coating. The concentration of the Me-4PACz precursor solution was 0.5 mg / mL, the solvent was ethanol, the spin coating speed was 3000 rpm, and the time was 30 min. After spin coating, the layer was placed on a heating stage for annealing to remove the remaining solvent. The annealing temperature was 100℃ and the time was 10 min.

[0088] (3) Cs were prepared on the hole transport layer by spin coating. 0.25 FA 0.75 Pb(I 0.8 Br 0.2 3. A perovskite active layer with a thickness of 700 nm was prepared. The perovskite precursor solution concentration was 1.7 M, and the solvent was DMF:DMSO (volume ratio 4:1). The spin-coating speed and time were 700 rpm for 5 s, 2000 rpm for 20 s, and 7000 rpm for 40 s, respectively. 10 s before the end of spin-coating, 200 μL of ethyl acetate was added dropwise. After spin-coating, the layer was annealed on a heating stage to remove residual solvent. The annealing temperature was 100 °C for 30 min.

[0089] (4) C is prepared by vapor deposition. 60 An electron transport layer, 20 nm thick, was deposited under high vacuum conditions (10 nm). -6 The deposition was carried out using Torr at a rate of 0.1 nm / s.

[0090] (5) SnO was prepared using atomic layer deposition process. x The buffer layer is 20 nm thick. The atomic layer deposition process uses tin tetrachloride and water vapor as the tin source and oxygen source, respectively, and performs alternating pulse deposition at 90 °C to complete 140 ALD cycles.

[0091] (6) Nano zinc oxide material is used as the adsorption layer material, with a pore size of 10 nm and a specific surface area of ​​40 m². 2 / g, dispersed in isopropanol solvent, with a mass fraction of 20%, to obtain a precursor solution; the precursor solution is heated at 100℃ for 30 min to ensure thorough dispersion; the precursor liquid is dropped onto a buffer layer and spin-coated at high speed using a spin coater at a speed of 3000 rpm for 25 s; after spin coating, it is placed on a heating stage for annealing to remove residual solvent at a temperature of 100℃ for 60 min, finally obtaining an adsorption layer with a thickness of 20 nm.

[0092] (7) A transparent conductive oxide layer of IZO with a thickness of 50 nm was prepared by magnetron sputtering. The magnetron sputtering process adopted DC sputtering mode, the target material was In2O3:ZnO (90wt%:10wt%), and the sputtering power was 140W.

[0093] (8) An Ag metal electrode layer with a thickness of 100 nm was prepared on a transparent conductive oxide layer by vapor deposition. The vapor deposition process was carried out under high vacuum conditions (10 nm). -6 The deposition process was carried out using a Torr evaporation method at a rate of 0.2 nm / s, with the metal electrode pattern defined by a metal mask.

[0094] Example 2

[0095] The method for preparing the solar cell in this embodiment is basically the same as that in Example 1. The difference is that in step (6), the rotation speed during spin coating is controlled to be 2000 rpm and the time is 20s, so the thickness of the adsorption layer prepared is 30 nm.

[0096] Example 3

[0097] The method for preparing the solar cell in this embodiment is basically the same as that in Example 1, except that in step (6), the pore size of zinc oxide is 40 nm and the specific surface area is 60 m². 2 / g.

[0098] Example 4

[0099] The method for preparing the solar cell in this embodiment is basically the same as that in Example 1, except that in step (6), the metal oxide material is replaced with titanium dioxide, with a pore size of 40 nm and a specific surface area of ​​50 m². 2 / g.

[0100] Example 5

[0101] The method for preparing the solar cell in this embodiment is basically the same as that in Example 1, except that in step (6), the metal oxide material is replaced with nano-alumina with a pore size of 30 nm and a specific surface area of ​​50 m². 2 / g.

[0102] Comparative Example 1

[0103] This comparative example provides a method for preparing a solar cell.

[0104] (1) An ITO tunneling composite layer with a thickness of 15 nm was prepared on a heterojunction substrate using magnetron sputtering. The magnetron sputtering process used In2O3:SnO2 (95 wt%:5 wt%) as the target material and 80 W as the sputtering power.

[0105] (2) A Me-4PACz hole transport layer with a thickness of 2 nm was prepared on the tunneling composite layer by spin coating. The concentration of the Me-4PACz precursor solution was 0.5 mg / mL, the solvent was ethanol, the spin coating speed was 3000 rpm, and the time was 30 min. After spin coating, the layer was placed on a heating stage for annealing to remove the remaining solvent. The annealing temperature was 100℃ and the time was 10 min.

[0106] (3) Cs were prepared on the hole transport layer by spin coating. 0.25 FA 0.75 Pb(I 0.8 Br 0.2 3. A perovskite active layer with a thickness of 700 nm was prepared. The perovskite precursor solution concentration was 1.7 M, and the solvent was DMF:DMSO (volume ratio 4:1). The spin-coating speed and time were 700 rpm for 5 s, 2000 rpm for 20 s, and 7000 rpm for 40 s, respectively. 10 s before the end of spin-coating, 200 μL of ethyl acetate was added dropwise. After spin-coating, the layer was annealed on a heating stage to remove residual solvent. The annealing temperature was 100 °C for 30 min.

[0107] (4) C is prepared by vapor deposition. 60 An electron transport layer, 20 nm thick, was deposited under high vacuum conditions (10 nm). -6 The deposition was carried out using Torr at a rate of 0.1 nm / s.

[0108] (5) SnO was prepared using atomic layer deposition process. x The buffer layer is 20 nm thick. The atomic layer deposition process uses tin tetrachloride and water vapor as the tin source and oxygen source, respectively, and performs alternating pulse deposition at 90 °C to complete 140 ALD cycles.

[0109] (6) A transparent conductive oxide layer of IZO with a thickness of 50 nm was prepared by magnetron sputtering. The magnetron sputtering process adopted DC sputtering mode, the target material was In2O3:ZnO (90 wt%:10 wt%), and the sputtering power was 140W.

[0110] (7) An Ag metal electrode layer with a thickness of 100 nm was prepared on a transparent conductive oxide layer by vapor deposition. The vapor deposition process was carried out under high vacuum conditions (10 nm). -6 The deposition process was carried out using a Torr evaporation method at a rate of 0.2 nm / s, with the metal electrode pattern defined by a metal mask.

[0111] Performance testing

[0112] (1) Photoelectric conversion performance test

[0113] The solar cells fabricated in the above embodiments and comparative examples were placed in a solar simulator (manufacturer: Wavelabs) and subjected to sunlight of a certain intensity. A bias voltage (V) was applied to the devices using a test source meter. p The bias voltage range is -0.1 to 2.2V, and the output current of the device is tested to obtain the bias voltage-current density curve.

[0114] Open circuit voltage (V) oc ): The terminal voltage of the solar cell when no load is connected, i.e., the current density in the bias-current density curve is 0 mA·cm. -2 The bias voltage value at that time.

[0115] Short-circuit current density (J) sc ): Output current per unit area of ​​the battery cell when short-circuited, i.e., the current density when the bias voltage is 0V in the bias voltage-current density curve.

[0116] Fill factor (FF): FF = max(V p ×J sc ), where V p J is the bias voltage. sc This represents the short-circuit current density.

[0117] Photovoltaic cell efficiency (PCE): PCE = V oc ×J sc ×FF.

[0118] (2) Long-term stability test

[0119] After the solar cells prepared in the above embodiments and comparative examples were placed for 1000 hours, the PCE retention rate was tested.

[0120] (3) Fracture energy and shear strength test

[0121] The interfacial fracture energy Gc was tested using the double cantilever beam method, and the interfacial shear strength τ was tested using the lap shear method. max .

[0122] Glass / SnO prepared on a glass substrate x / IZO and glass / SnO x / Adsorption layer / IZO sample.

[0123] Fracture energy test: The two ends of the sample are bonded to a rigid metal beam and stretched at a constant rate. The peak load F during steady-state crack propagation is recorded. max Measure the crack length a, by Calculate the fracture energy (b is the sample width, h is the substrate thickness, and E is the glass Young's modulus).

[0124] Shear strength test: The TCO surface of the sample was bonded to another glass substrate with epoxy resin to form an overlap structure (overlap area A). A shear force was applied at a constant rate, and the maximum load F at interface failure was recorded. max , through τ max =F max / A calculates the shear strength of the interface.

[0125] The test results for the above performance are shown in Table 1.

[0126] Table 1

[0127]

[0128] As shown in Table 1, comparing Examples 1-5 and Comparative Example 1, it can be seen that the solar cell provided in this application exhibits significant advantages in terms of photoelectric conversion performance, interfacial bonding strength, and long-term stability.

[0129] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0130] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A solar cell, characterized in that, It includes a substrate, a first charge transport layer, a perovskite active layer, a second charge transport layer, an adsorption layer, and a transparent conductive oxide layer, which are stacked sequentially. The adsorption layer comprises a metal oxide material having a nanoporous structure.

2. The solar cell according to claim 1, characterized in that, It also includes a buffer layer, which is stacked between the second charge transport layer and the adsorption layer, and the buffer layer includes tin oxide material.

3. The solar cell according to claim 1, characterized in that, The thickness of the adsorption layer is 1 nm to 50 nm.

4. The solar cell according to any one of claims 1 to 3, characterized in that, The metal oxide material satisfies at least one of the following conditions: (1) The metal oxide material includes at least one of zinc oxide, titanium dioxide, tungsten trioxide, nickel oxide, cobalt tetroxide, cuprous oxide, zirconium dioxide, niobium pentoxide and zinc stannate; (2) The pore size of the metal oxide material is 1 nm to 40 nm; (3) The specific surface area of ​​the metal oxide material is 1 m². 2 / g~200 m 2 / g.

5. The solar cell according to any one of claims 1 to 3, characterized in that, The substrate is a crystalline silicon cell, and the solar cell further includes a tunneling composite layer, which is stacked between the crystalline silicon cell and the first charge transport layer.

6. A method for preparing a solar cell, characterized in that, Includes the following steps: A first charge transport layer, a perovskite active layer, and a second charge transport layer are sequentially formed on a substrate to prepare a stacked structure. An adsorption layer is formed on the side of the stacked structure away from the substrate, the adsorption layer comprising a metal oxide material having a nanoporous structure; A transparent conductive oxide layer is formed on the adsorption layer using a magnetron sputtering process to prepare a solar cell.

7. The method for preparing a solar cell according to claim 6, characterized in that, Forming an adsorption layer on the side of the laminated structure away from the substrate specifically includes the following steps: A precursor solution is prepared by dispersing metal oxide materials in a solvent; The precursor liquid is deposited onto the side of the laminated structure away from the substrate to form an adsorption layer; the deposition method includes at least one of spin coating, spraying, inkjet printing, blade coating, slot coating or immersion.

8. The method for preparing a solar cell according to claim 7, characterized in that, At least one of the following conditions must be met: (1) The mass percentage of the metal oxide material in the precursor solution is 1% to 40%; (2) The solvent is selected from at least one of ethylene glycol methyl ether, isopropanol, ethanol and toluene; (3) After preparing the precursor liquid, the step further includes: dispersing the precursor liquid by shaking and / or heating.

9. The method for preparing a solar cell according to any one of claims 6 to 8, characterized in that, The stacked structure further includes a buffer layer, which is formed on the surface of the second charge transport layer by an atomic layer deposition process, and the buffer layer includes tin oxide material.

10. A photovoltaic module, characterized in that, This includes solar cells as described in any one of claims 1 to 5, or solar cells prepared by any one of claims 6 to 9.

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