A solar cell and a method of manufacturing the same

Abstract

This application relates to the field of photovoltaic power generation technology and discloses a solar cell and its fabrication method, which solves the problem that current electrode layers are difficult to balance adhesion and contact resistance. The solar cell includes a cell body and an electrode layer; wherein the electrode layer includes a graphene layer containing metal atoms and / or an alloy layer.

Description

Technical Field

[0001] This application relates to the field of photovoltaic power generation technology, and in particular to a solar cell and a method for its fabrication. Background Technology

[0002] Contact resistance is a key factor affecting the photoelectric conversion efficiency and other performance characteristics of crystalline silicon solar cells, making its reduction crucial. In current technologies, insufficient treatment of the interface characteristics between the electrode and the cell substrate during electrode fabrication often sacrifices conductivity to ensure electrode adhesion, resulting in high contact resistance. This leads to excessive resistance during carrier transport, consequently reducing the solar cell's photoelectric conversion efficiency and other performance characteristics. Therefore, current solar cell technology faces the challenge of balancing electrode adhesion and contact resistance effectively. Summary of the Invention

[0003] This invention provides a solar cell and its fabrication method to solve the problem that current electrode layers are difficult to balance adhesion and contact resistance.

[0004] In a first aspect, embodiments of this application provide a solar cell, including a cell body and an electrode layer; wherein the electrode layer includes a graphene layer containing metal atoms and / or an alloy layer.

[0005] In some embodiments, the metal atoms include at least one selected from Ni atoms, Cu atoms, Au atoms, Ag atoms, Pd atoms, and Pt atoms. Preferably, the metal atoms are any one of Ni atoms, Cu atoms, and Au atoms.

[0006] In some embodiments, the doping concentration of the metal atoms in the graphene layer is 0.1 at% to 0.5 at%.

[0007] In some embodiments, the alloy layer comprises at least two of Ni atoms, Al atoms, Mg atoms, and Cu atoms. Preferably, the alloy layer (102) is a nickel-aluminum alloy; more preferably, the molar ratio of Ni atoms to Al atoms in the nickel-aluminum alloy is 1:(0.1~0.5), and more preferably 1:(0.2~0.3).

[0008] In some embodiments, the metal atoms include at least one selected from Ni atoms, Cu atoms, Au atoms, Ag atoms, Pd atoms, and Pt atoms; and / or, The doping concentration of the metal atoms in the graphene layer is 0.1 at% to 0.5 at%; and / or, The alloy layer comprises at least two of Ni atoms, Al atoms, Mg atoms, and Cu atoms.

[0009] In some embodiments, the metal atom is any one of Ni, Cu, and Au atoms; and / or, The alloy layer is a nickel-aluminum alloy; wherein the molar ratio of Ni atoms to Al atoms in the nickel-aluminum alloy is 1:(0.1~0.5).

[0010] In some embodiments, the electrode layer is composed of the graphene layer and the alloy layer in sequence along the direction away from the battery body.

[0011] In some embodiments, the thickness of the graphene layer is 1-5 nm; the thickness of the alloy layer is 20-100 nm.

[0012] In some embodiments, the conductivity enhancement factor S of the graphene layer satisfies: S ≥ 1.2, preferably S is 1.2~3; the contact resistance of the electrode layer satisfies: ≤2×10 -8 Ω·cm 2 The preferred value for Rc is 1×10. -9 ~2×10 -8 Ω·cm 2 ;in, ; ; In the formula, This indicates the electrical conductivity of the graphene layer. The value represents the electrical conductivity of the graphene layer that does not contain the metal atoms, and W represents the total width of the electrode layer. This indicates the electrical conductivity of the graphene layer. This indicates the electrical conductivity of the alloy layer. This indicates the thickness of the graphene layer. This indicates the thickness of the alloy layer.

[0013] In some embodiments, the thickness of the graphene layer is 1-5 nm; the thickness of the alloy layer is 20-100 nm; and / or, The conductivity enhancement factor S of the graphene layer satisfies: S≥1.2; the contact resistance of the electrode layer satisfies: ≤2×10 -8 Ω·cm 2 ;in, ; ; In the formula, This indicates the electrical conductivity of the graphene layer. The value represents the electrical conductivity of the graphene layer that does not contain the metal atoms, and W represents the total width of the electrode layer. This indicates the electrical conductivity of the graphene layer. This indicates the electrical conductivity of the alloy layer. This indicates the thickness of the graphene layer. This indicates the thickness of the alloy layer.

[0014] In some embodiments, an electrode protective layer is disposed on the side of the electrode layer away from the battery body; wherein the electrode protective layer comprises silicon nitride and silicon dioxide.

[0015] In some embodiments, the thickness of the electrode protective layer is 5-10 nm.

[0016] Secondly, embodiments of this application provide a method for preparing a solar cell as described in the first aspect and any embodiment, comprising: In the electrode region of the battery body, a graphene layer containing metal atoms is deposited, and / or an alloy layer is deposited; and annealing is performed to obtain the electrode layer.

[0017] In some embodiments, the graphene layer is obtained by atomic layer deposition, and the alloy layer is obtained by magnetron sputtering; wherein the conditions for atomic layer deposition include a deposition rate of 0.1~0.5 Å / cycle, and the conditions for magnetron sputtering include 0.5~2.0 W / cm². 2 The power density and air pressure of 0.1~1.0 Pa.

[0018] In some embodiments, the annealing conditions include: an inert gas protective atmosphere, an annealing temperature of 200~400°C, and an annealing time of 5~30 minutes.

[0019] In some embodiments, after obtaining the electrode layer, the process further includes: Silicon nitride and silicon dioxide are deposited on the electrode layer to form an electrode protective layer.

[0020] In some embodiments, silicon nitride and silicon dioxide are deposited on the electrode layer by plasma-enhanced chemical vapor deposition.

[0021] Thirdly, embodiments of this application provide a photovoltaic module, comprising: The solar cell described in the first aspect and any embodiment thereof.

[0022] The solar cell provided by this invention can reduce the series resistance between the electrode layer and the cell body and decrease the contact resistance of the electrode layer by utilizing the ultra-high intrinsic mobility of the dense graphene layer in the electrode layer. Furthermore, the SP of the graphene layer... 2The lattice exhibits excellent doping compatibility with metal atoms, which enables it to exhibit good carrier transport performance. At the same time, the metal atoms in the graphene layer can form an alloy phase with Si in the battery body to achieve metallurgical bonding, thus possessing strong adhesion.

[0023] And / or, the alloy layer, as an alloy phase, has a crystal structure dominated by metallic bonds, exhibiting few defects and dense characteristics, thus possessing high conductivity. Therefore, when the alloy layer is used as an electrode layer, it can reduce the contact resistance of the electrode layer. At the same time, the atoms of the alloy phase can also form metallurgical bonds with the metal atoms in the silicon or graphene layer in the battery body, thus exhibiting strong adhesion. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the electrode layer structure in one embodiment; Figure 2 This is a schematic diagram of the electrode layer structure in another embodiment; Figure 3 This is a schematic diagram of the electrode layer structure in another embodiment; The reference numerals in the accompanying drawings include: 100 - Electrode layer; 101 - Graphene layer; 102 - Alloy layer. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0026] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the document does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0027] As illustrated herein, unless the context clearly indicates otherwise, the words “a,” “an,” “an,” and / or “the” do not specifically refer to the singular and may also include the plural. Generally speaking, the terms “comprising” and “including” only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0028] To address the challenge of balancing contact resistance and adhesion of electrodes in solar cells, this application provides a solar cell comprising a cell body and an electrode layer 100. The electrode layer 100 includes a graphene layer 101 containing metal atoms and / or an alloy layer 102.

[0029] In the solar cell provided in this application embodiment, when the electrode layer 100 includes a graphene layer 101 containing metal atoms, the graphene layer 101 has an ultra-high intrinsic mobility, which can provide the electrode layer 100 with extremely high in-plane resistance, reducing series resistance and contact resistance. Simultaneously, due to the SP properties of graphene... 2 The carbon structure exhibits good compatibility with metal atoms, and the metal atoms in the graphene layer 101 can form a strong metallurgical bond with the silicon substrate in the battery body. Therefore, the graphene layer 101 effectively improves the mechanical adhesion and mechanical stability between the electrode layer 100 and the battery body. Furthermore, the graphene layer 101 containing metal atoms possesses a certain electrical conductivity, enabling efficient extraction of charge carriers when the solar cell is exposed to light. This effectively improves the conductivity of the interface between the electrode layer 100 and the battery body, and reduces the contact resistance between them.

[0030] When the electrode layer 100 includes an alloy layer 102, the alloy layer 102 can be metallurgically bonded to the underlying graphene layer 101 or the surface of the battery body, ensuring strong mechanical adhesion of the electrode layer 100. Simultaneously, because the alloy layer 102 comprises multiple metal atoms forming a single crystal phase, it obviously exhibits fewer interface defects. Therefore, the alloy layer 102 can significantly improve the conductivity of the electrode layer 100 and effectively reduce its contact resistance.

[0031] Optionally, the electrode layer 100 may include a graphene layer 101 containing metal atoms, please refer to [reference needed]. Figure 1 .

[0032] Optionally, the electrode layer 100 mentioned above includes an alloy layer 102, please refer to... Figure 2 .

[0033] Optionally, the electrode layer 100 includes a graphene layer 101 and an alloy layer 102. More preferably, when the electrode layer 100 includes both a graphene layer 101 and an alloy layer 102, the graphene layer 101 is disposed between the battery body and the alloy layer 102.

[0034] For example, an anti-reflection layer may be provided on the surface of the battery body, and then the graphene layer 101 is attached to the anti-reflection layer of the battery body.

[0035] To further reduce the contact resistance between the electrode layer 100 and the battery body, metal atoms with work functions matching those of the silicon substrate can be selected and doped into the graphene layer 101. Optionally, the metal atoms may include at least one of Ni, Cu, Au, Ag, Pd, and Pt atoms. Thus, by using these metal atoms, the contact resistance between the graphene layer 101 and the battery body can be further reduced, while simultaneously reducing energy barriers and charge accumulation at the interface, stabilizing the interface between the electrode layer 100 and the battery body, and improving the adhesion stability of the electrode layer 100.

[0036] To further reduce the contact resistance between the graphene layer and the battery body and ensure stable mechanical adhesion, in one embodiment, the metal atoms may include any one of Ni atoms, Cu atoms, and Au atoms.

[0037] Among them, Ni atoms can form d-π orbital hybridization (SP) with C atoms. 2 (Hybridized bonds), Cu atoms and Au atoms can modulate the Fermi level of graphene layer 101 through a work function-induced charge transfer mechanism, thereby enhancing the carrier concentration in graphene layer 101.

[0038] To further enhance the carrier concentration in the graphene layer 101 by doping it with metal atoms, and to avoid graphene lattice distortion and reduced interface uniformity due to excessive doping concentration, in one embodiment, the doping concentration of metal atoms in the graphene layer 101 is 0.1at% to 0.5at% (i.e., the percentage of metal atoms to the total number of atoms). Exemplarily, the doping concentration of metal atoms in the graphene layer 101 can be 0.1at%, 0.2at%, 0.3at%, 0.4at%, 0.5at%, or a range selected from any combination thereof.

[0039] Furthermore, the metal atoms in the alloy layer 102 may include at least two of Ni atoms, Al atoms, Mg atoms, and Cu atoms.

[0040] Preferably, the metal atoms in alloy layer 102 may include Ni atoms and Al atoms. Therefore, alloy layer 102 may comprise a nickel-aluminum alloy.

[0041] Preferably, the molar ratio of Ni atoms to Al atoms in the nickel-aluminum alloy is 1:(0.1~0.5). More preferably, the molar ratio of Ni atoms to Al atoms in the nickel-aluminum alloy is 1:(0.2~0.3).

[0042] In this embodiment, the preferred electrode layer 100 is composed of the aforementioned graphene layer 101 and alloy layer 102. Please refer to... Figure 3 .

[0043] Along the direction away from the battery body, there are graphene layer 101 and alloy layer 102 in sequence.

[0044] Thus, the contact resistance is reduced through the graphene layer 101 containing metal atoms. Furthermore, the graphene layer 101 can act as a transition layer between the battery body and the alloy layer 102, reducing interfacial stress. Simultaneously, metallurgical bonding is achieved through the gradual transition region formed by the interdiffusion of metal atoms between the graphene layer 101 and the alloy layer 102. In particular, the metal atoms doped in the graphene layer 101 provide high activity to its surface, promoting the formation of metallic bonds (strong chemical bonds) with the alloy layer 102, thereby further enhancing the mechanical stability of the electrode layer 100 and its adhesion to the battery body interface.

[0045] Furthermore, without affecting light absorption, in order to improve the lateral transport and collection efficiency of charge carriers, the thickness of graphene layer 101 is less than or equal to 5 nm.

[0046] Optionally, the thickness of the graphene layer 101 is 1~5 nm to ensure that the graphene layer 101 can be doped with a corresponding amount of metal atoms, so that the metal atoms have sufficient bonding sites with the upper and lower layers of the graphene layer 101, thereby improving the adhesion stability. For example, the thickness of the graphene layer 101 is 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, or selected from any two of the above ranges.

[0047] Furthermore, the thickness of the alloy layer 102 is greater than 20 nm, for example, it can be 20~100 nm, in order to provide a continuous conductive network and avoid the problem of excessive line resistance caused by the alloy layer 102 being too thin when it is distributed on the surface of the battery body in the form of grid lines or interdigitated fingers, as well as the problem of stress concentration caused by the alloy layer 102 being too thick.

[0048] Preferably, the thickness of the alloy layer 102 is 20-30 nm. For example, the thickness of the alloy layer 102 can be 20 nm, 22 nm, 24 nm, 26 nm, 28 nm, 30 nm, or a range selected from any two of the above.

[0049] Furthermore, the aforementioned electrode layer 100 achieves the advantages of both strong adhesion and low contact resistance. Optionally, the contact resistance of the aforementioned electrode layer 100 satisfies: R c ≤2×10 -8 Ω·cm 2 ;in, W represents the total width of electrode layer 100, σ represents the conductivity of electrode layer 100, and d represents the thickness of electrode layer 100. The electrical conductivity of the aforementioned graphene layer 101 containing metal atoms is represented by W, and the total width of the electrode layer 100 is represented by W. This indicates the electrical conductivity of the graphene layer 101. This indicates the electrical conductivity of the alloy layer 102. This indicates the thickness of graphene layer 101. This indicates the thickness of the alloy layer 102.

[0050] That is, the contact resistance Rc is obtained by calculating the reciprocal of the product of the total width of the electrode layer 100 and the conductivity and thickness of the electrode layer 100. When the electrode layer 100 is composed of multiple layers of different materials, the product of the conductivity and thickness of each layer is calculated separately, then summed and multiplied by the total width of the electrode layer 100, and the reciprocal is calculated to obtain the contact resistance of the electrode layer 100 composed of multiple layers.

[0051] The following is for R c The formula and its meaning are explained as follows: In electrode layer 100, graphene layer 101 and alloy layer 102 are considered as two conductive channels connected in series. However, when graphene layer 101 and alloy layer 102 in electrode layer 100 are considered as an equivalent conductive model, since they are connected in parallel in the horizontal direction, a parallel resistance model is formed, resulting in the total conductance of the parallel resistance model. Then, with Multiplying these components and normalizing them to a unit width yields the above R. c The calculation formula.

[0052] A lower Rc indicates higher interfacial transport efficiency. Furthermore, the presence of interfacial defects such as voids and impurities increases scattering, reduces effective conductivity, and raises Rc. Therefore, a lower Rc indicates fewer interfacial defects between the electrode layer 100 and the battery body. Additionally, a lower Rc also signifies a higher degree of alloying in the electrode layer 100, such as the formation of intermetallic compounds like NiSi2 and NiAl. These chemical bonds (metallurgical bonding) are stronger than physical adsorption, ensuring a more stable and firm adhesion of the electrode layer 100 to the battery body. Therefore, in this embodiment, Rc can be used to characterize the electrode layer 100 as possessing both good adhesion and good contact resistance.

[0053] Understandably, when the electrode layer 100 is distributed on the surface of the battery body in the form of grid lines or interdigitated electrodes, the total width W of the electrode layer 100 can be the sum of the widths of each grid line or the sum of the widths of the interdigitated electrodes. This width can be characterized by SEM (Scanning Electron Microscopy).

[0054] In one embodiment, Rc is 1×10 -9 ~2×10 -8 Ω·cm2 .

[0055] For example, the graphene layer 101 is doped with 0.1 at% Ni atoms, and the corresponding electrical conductivity of the graphene layer 101 is 1.2 × 10⁻⁶. 6 S / m; The thickness of graphene layer 101 is 5 nm. The molar ratio of Ni atoms to Al atoms in alloy layer 102 is 1:0.5, and the conductivity of alloy layer 102 is 5 × 10⁻⁶. 6 S / m, the thickness of alloy layer 102 is 100nm. Since the total width of electrode layer 100 is generally about 1cm or larger, in this embodiment, W is set to 1cm to calculate R. c : .

[0056] Continuing with the example: Graphene layer 101 is doped with 0.5 at% Au atoms, corresponding to an electrical conductivity of 3 × 10⁻⁶. 6 S / m; The thickness of graphene layer 101 is 1 nm. In alloy layer 102, the molar ratio of Ni atoms to Al atoms is 1:0.2, at which point the Ni3Al phase dominates in alloy layer 102, and the electrical conductivity of alloy layer 102 is 2 × 10⁻⁶. 7 S / m, the thickness of alloy layer 102 is 50nm. Still setting W to 1cm, we get R. c as follows: .

[0057] Furthermore, the graphene layer 101 has a high conductivity enhancement factor, and its conductivity enhancement factor S satisfies: S≥1.2.

[0058] in, , This represents the electrical conductivity of graphene layer 101, specifically the electrical conductivity of graphene layer 101 doped with metal atoms. This indicates the electrical conductivity of a graphene layer that does not contain metal atoms.

[0059] As can be seen from the formula for the conductivity enhancement factor S, the effect of metal atom doping on the carrier mobility improvement in graphene is quantified by calculating the ratio. Specifically, a higher S indicates a stronger bond strength (e.g., d-π hybridization) between the dopant atoms and graphene, resulting in smoother interfacial electron transport. This reduces interfacial energy barriers and charge accumulation, improving the mechanical stability and adhesion of electrode layer 100 on the battery body. Simultaneously, graphene layer 101 acts as a dense diffusion barrier layer, preventing excessive diffusion of metal atoms into the battery body, thus preventing the formation of high-resistance phases (such as voids caused by excess Al). Therefore, graphene layer 101 helps prevent the increase of interfacial defects. Thus, a higher S also synergistically reduces interfacial defects, resulting in good contact resistance in electrode layer 100.

[0060] In one embodiment, S can be as high as 2.5 to 3.0. For example, S is 1.2 to 3.

[0061] For example, the graphene layer 101 is doped with 0.1 at% Ni atoms, and the corresponding conductivity of the graphene layer 101 is... 1.2×10 6 S / m, while the conductivity of graphene layers without metal atoms 1×10 6 If S / m is obtained, then S=1.2 can be obtained for graphene layer 101.

[0062] When 0.5 at% Au atoms are doped into graphene layer 101, the electrical conductivity of graphene layer 101 is... 3×10 6 S / m; at this time, S=3 for graphene layer 101.

[0063] Because the electrode layer 100 in this embodiment has a low contact resistance Rc and a high conductivity enhancement factor S, the electrode layer 100 has the characteristics of strong adhesion, high mechanical stability and low interface defects.

[0064] Furthermore, to further improve the passivation performance of the solar cell and prevent the electrode layer 100 from being attacked by water and oxygen or subjected to mechanical wear during the use of the solar cell, in one embodiment, the solar cell further includes an electrode protective layer, which comprises silicon nitride (SiN). x And silicon dioxide (SiO2).

[0065] Optionally, the electrode protective layer is made of silicon nitride (SiN). x It is composed of silicon dioxide (SiO2).

[0066] In one embodiment, the thickness of the electrode protective layer is 5-10 nm.

[0067] In one embodiment, when the battery body includes an antireflection layer, the aforementioned electrode layer 100 is disposed above the antireflection layer. The antireflection layer may be SiNx.

[0068] Furthermore, the aforementioned battery body may include, but is not limited to, the battery body of PERC (Passivated Emitter and RearCell), TOPCon (Tunnel Oxide Passivated Contact), IBC (Interdigitated Back Contact), and HJT (Heterojunction with Intrinsic Thin-layer) batteries.

[0069] For example, when the solar cell is a PERC cell, the cell body may include a silicon substrate and a passivation layer disposed on the back surface of the silicon substrate. The passivation layer may be, for example, aluminum oxide (Al2O3) or silicon nitride (SiNx).

[0070] For example, when the solar cell is a TOPCon cell, the cell body may include a silicon substrate, and a tunneling oxide layer and a doped polycrystalline silicon layer disposed on the back side of the silicon substrate.

[0071] For example, when the solar cell is an HJT cell, the cell body may include a silicon substrate and an intrinsic and amorphous silicon thin film disposed on the back side of the silicon substrate.

[0072] Based on the same inventive concept, this application provides a method for preparing a solar cell, which includes the following steps: In the electrode region of the battery body, a graphene layer 101 containing doped metal is deposited, and / or an alloy layer 102 is deposited; and annealing is performed to obtain an electrode layer 100.

[0073] In one embodiment, the graphene layer 101 is obtained by atomic layer deposition (ALD), and the alloy layer 102 is obtained by magnetron sputtering.

[0074] In the above preparation method, annealing can promote the diffusion of metal atoms in graphene layer 101 into adjacent layers to form an alloy phase. For example, when the metal atoms in graphene layer 101 include Ni, Ni atoms can diffuse into the battery body during annealing, forming metal silicides at the interface with the battery body. This is an atomic-scale, strong chemical bond, thus exhibiting high adhesion. The metal atoms in graphene layer 101 can also effectively improve its conductivity when used as electrode layer 100, reducing contact resistance. This graphene layer 101 also possesses stable properties and excellent doping compatibility with metal atoms.

[0075] Furthermore, atomic layer deposition is used in the preparation of graphene layer 101, which can achieve ultrathin and continuous graphene layer 101, effectively avoiding the sacrifice of light absorption efficiency, while effectively improving the efficiency of lateral carrier transport.

[0076] Alternatively, during the annealing process, metal atoms in the alloy layer 102 also diffuse, forming a strong metallurgical bond with the interface of its underlying layer, thus possessing strong mechanical adhesion. Furthermore, the magnetron sputtering used in the alloy layer 102 can effectively reduce the density of the alloy layer 102.

[0077] Alternatively, when graphene layer 101 and alloy layer 102 are deposited in the electrode region, the bombardment effect of high-energy particles during the formation of alloy layer 102 by magnetron sputtering can clean impurities in the pores of graphene layer 101 while activating the surface of graphene layer 101, thus promoting a tighter bond between alloy layer 102 and graphene layer. This ensures a tight bond between graphene layer 101 and alloy layer 102, resulting in low contact resistance and strong adhesion.

[0078] In one embodiment, in the battery body described above, the surface impurity concentration C of the PN junction (or high / low junction) is... surface satisfy: .

[0079] Furthermore, the aforementioned metal atoms may include at least one of Ni atoms, Cu atoms, Au atoms, Ag atoms, Pd atoms, and Pt atoms.

[0080] In one embodiment, the metal atoms may include any one of Ni atoms, Cu atoms, and Au atoms.

[0081] To further enhance the density of the graphene layer 101, in one embodiment, the atomic layer deposition conditions include a deposition rate of 0.1–0.5 Å / cycle. The number of deposition cycles and the deposition time are adjusted according to the actual thickness of the graphene layer 101 to be deposited.

[0082] The metal atoms in the alloy layer 102 may include at least two of Ni atoms, Al atoms, Mg atoms, and Cu atoms. Preferably, the metal atoms in the alloy layer 102 may include Ni atoms and Al atoms.

[0083] To further improve the density of the alloy layer 102 and reduce defects therein, in one embodiment, the alloy layer 102 is prepared by the following method: With a power density of 0.5~2.0 W / cm² 2 Under a gas pressure of 0.1~1.0 Pa, nickel and aluminum targets were sputtered by magnetron sputtering to obtain alloy layer 102; wherein the molar ratio of nickel atoms to aluminum atoms in alloy layer 102 is 1:(0.1~0.5).

[0084] The conditions for magnetron sputtering include 0.5~2.0 W / cm². 2 The power density and gas pressure are 0.1~1.0 Pa. In addition, the magnetron sputtering time is adjusted according to the actual thickness of the alloy layer 102 to be deposited.

[0085] In one embodiment, the annealing conditions include: an inert gas protective atmosphere, an annealing temperature of 200~400°C, and an annealing time of 5~30 min.

[0086] For example, when the electrode layer 100 includes a graphene layer 101 and an alloy layer 102, it is annealed in an inert atmosphere at 200~400°C for 5~30 minutes to bond the metal atoms in the graphene layer 101 to the silicon atoms in the battery body, and the metal atoms in the graphene layer 101 to the metal atoms in the alloy layer 102, thus forming a metallurgical bond and obtaining an electrode layer 100 with strong adhesion and low contact resistance.

[0087] Furthermore, after obtaining the electrode layer 100, an electrode protective layer can be deposited on the air-facing side of the electrode layer 100 by plasma-enhanced chemical vapor deposition (PECVD); that is, silicon nitride (SiN) can be deposited on the electrode layer 100. x It combines silicon dioxide (SiO2) to obtain an electrode protective layer, thereby achieving passivation and protecting the electrode layer 100 from mechanical wear and water and oxygen damage.

[0088] In one embodiment, the PECVD deposition conditions may include a temperature of 400-500°C. The deposition time is adjusted according to the required thickness of the protective layer to be deposited.

[0089] Based on the same inventive concept, this application also provides a photovoltaic module, including the aforementioned solar cell.

[0090] For specific limitations on solar cells in photovoltaic modules, please refer to the limitations on solar cells and their preparation methods mentioned above, which will not be repeated here.

[0091] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A solar cell, comprising a cell body and an electrode layer (100), characterized in that, The electrode layer (100) includes a graphene layer (101) containing metal atoms and / or an alloy layer (102).

2. The solar cell as described in claim 1, characterized in that, The metal atoms include at least one selected from Ni atoms, Cu atoms, Au atoms, Ag atoms, Pd atoms, and Pt atoms; and / or, The doping concentration of the metal atoms in the graphene layer (101) is 0.1 at% to 0.5 at%; and / or, The alloy layer (102) includes at least two of Ni atoms, Al atoms, Mg atoms and Cu atoms.

3. The solar cell as described in claim 2, characterized in that, The metal atom is any one of Ni, Cu, and Au atoms; and / or, The alloy layer (102) is a nickel-aluminum alloy; wherein, the atomic molar ratio between Ni atoms and Al atoms in the nickel-aluminum alloy is 1:(0.1~0.5).

4. The solar cell according to any one of claims 1 to 3, characterized in that, Along the direction away from the battery body, the electrode layer (100) is composed of the graphene layer (101) and the alloy layer (102) in sequence.

5. The solar cell as described in claim 4, characterized in that, The thickness of the graphene layer (101) is 1~5 nm; the thickness of the alloy layer (102) is 20~100 nm; and / or, The conductivity enhancement factor S of the graphene layer (101) satisfies: S≥1.2; the contact resistance of the electrode layer (100) satisfies: ≤2×10 -8 Ω·cm 2 ;in, ； ； In the formula, This indicates the electrical conductivity of the graphene layer (101). The value represents the electrical conductivity of the graphene layer that does not contain the metal atoms, and W represents the total width of the electrode layer (100). This indicates the electrical conductivity of the graphene layer (101). This indicates the electrical conductivity of the alloy layer (102). This indicates the thickness of the graphene layer (101). This indicates the thickness of the alloy layer (102).

6. The solar cell according to any one of claims 1 to 3, characterized in that, An electrode protective layer is provided on the side of the electrode layer (100) away from the battery body; wherein the electrode protective layer includes silicon nitride and silicon dioxide.

7. The solar cell as claimed in claim 6, characterized in that, The thickness of the electrode protective layer is 5~10nm.

8. A method for preparing a solar cell according to any one of claims 1 to 7, characterized in that, include: In the electrode region of the battery body, a graphene layer (101) containing metal atoms is deposited, and / or an alloy layer (102) is deposited. The electrode layer (100) is obtained by annealing.

9. The method as described in claim 8, characterized in that, The graphene layer (101) is obtained by atomic layer deposition, and the alloy layer (102) is obtained by magnetron sputtering. The atomic layer deposition conditions include a deposition rate of 0.1–0.5 Å / cycle, and the magnetron sputtering conditions include a rate of 0.5–2.0 W / cm². 2 The power density and the air pressure of 0.1~1.0 Pa; and / or, The annealing conditions include: an inert gas protective atmosphere, an annealing temperature of 200~400℃, and an annealing time of 5~30min.

10. The method as described in claim 8, characterized in that, After obtaining the electrode layer (100), the process further includes: Silicon nitride and silicon dioxide are deposited on the electrode layer (100) to form an electrode protective layer.

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