Crystalline silicon solar cell based on molybdenum oxide layer and method of manufacturing the same
By employing reactive plasma deposition and precisely controlling the oxygen concentration distribution in the molybdenum oxide layer and the amorphous silicon oxygen passivation layer, the fabrication challenges of molybdenum oxide thin film layers in crystalline silicon solar cells have been solved, improving the photoelectric conversion efficiency and stability of the cells, making them suitable for industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
- Filing Date
- 2026-02-24
- Publication Date
- 2026-05-29
AI Technical Summary
In the fabrication process of existing crystalline silicon solar cells, it is difficult to control the thickness of the undoped molybdenum oxide thin film layer. Sputtering methods can easily damage the surface, and oxygen in the molybdenum oxide migrates to the amorphous silicon passivation layer, affecting the cell performance.
A molybdenum oxide layer was prepared by reactive plasma deposition. Combined with a first and second intrinsic amorphous silicon oxide passivation layer with low oxygen concentration and a third intrinsic amorphous silicon oxide passivation layer with high oxygen concentration, the conductivity of the hole transport layer and the interface passivation effect were optimized by precisely controlling the film thickness and oxygen distribution.
It improves the photoelectric conversion efficiency and stability of crystalline silicon solar cells, reduces the diffusion probability of oxygen in the molybdenum oxide layer, maintains high work function performance, and is suitable for industrial applications.
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Figure CN122121340A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of solar cell technology, specifically to a crystalline silicon solar cell based on a molybdenum oxide layer and its fabrication method. Background Technology
[0002] In solar cells such as crystalline silicon and crystalline silicon-cadmium telluride stacks, the hole transport layer can be made of undoped metal oxides with high work functions, such as molybdenum oxide, tungsten oxide, and vanadium oxide. Band bending occurs at the interface between the crystalline silicon and the metal oxide, enabling selective hole transport. This type of cell avoids the use of toxic and harmful gases during fabrication and reduces parasitic light absorption by the hole transport layer. However, it also has significant drawbacks: undoped molybdenum oxide and other metal oxide thin films are typically prepared by evaporation or sputtering. Evaporation methods are difficult to control the thickness, while sputtering methods cause significant surface damage. Furthermore, when using intrinsic amorphous silicon passivation layers, oxygen from the molybdenum oxide readily migrates to the passivation layer during solar cell annealing, altering the stoichiometry of the molybdenum oxide film and reducing its work function, thus affecting cell performance. Summary of the Invention
[0003] In view of the above problems, this application provides a crystalline silicon solar cell based on a molybdenum oxide layer and a method for its fabrication.
[0004] According to a first aspect of this application, a crystalline silicon solar cell based on a molybdenum oxide layer is provided, comprising a first transparent conductive layer, an N-type amorphous silicon layer, a first intrinsic amorphous silicon oxide passivation layer, an N-type crystalline silicon layer, a second intrinsic amorphous silicon oxide passivation layer, a third intrinsic amorphous silicon oxide passivation layer, a molybdenum oxide layer, and a second transparent conductive layer, wherein the oxygen concentration in the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer is lower than the oxygen concentration in the third intrinsic amorphous silicon oxide passivation layer.
[0005] According to embodiments of this application, the thickness of the molybdenum oxide layer is 1~10 nm.
[0006] According to embodiments of this application, the thickness of the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer are both 1~10nm, and the thickness of the third intrinsic amorphous silicon oxide passivation layer is 1~5nm.
[0007] The second aspect of this application provides a method for fabricating a crystalline silicon solar cell based on a molybdenum oxide layer, comprising: depositing a first intrinsic amorphous silicon oxide passivation layer and a second intrinsic amorphous silicon oxide passivation layer on the front and back surfaces of an N-type crystalline silicon cell, respectively; sequentially depositing an N-type amorphous silicon layer and a first transparent conductive layer on the side of the first intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon; and sequentially depositing a third intrinsic amorphous silicon oxide passivation layer, a molybdenum oxide layer, and a second transparent conductive layer on the side of the second intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon; wherein the oxygen concentration in the first and second intrinsic amorphous silicon oxide passivation layers is lower than the oxygen concentration in the third intrinsic amorphous silicon oxide passivation layer.
[0008] According to an embodiment of this application, the molybdenum oxide layer is prepared by reactive plasma deposition.
[0009] According to the embodiments of this application, the proportion of metallic molybdenum doped in the target material during the preparation of the molybdenum oxide layer is less than or equal to 10%.
[0010] According to an embodiment of this application, when depositing the molybdenum oxide layer, the oxygen content in the introduced gas is greater than or equal to 20%, and the thickness of the molybdenum oxide layer is 1~10 nm.
[0011] According to embodiments of this application, the first intrinsic amorphous silicon oxide passivation layer, the second intrinsic amorphous silicon oxide passivation layer, and the third intrinsic amorphous silicon oxide passivation layer are all achieved by plasma-enhanced chemical vapor deposition.
[0012] According to the embodiments of this application, when depositing the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer, the carbon dioxide content in the introduced gas is 1% to 10%; when depositing the third intrinsic amorphous silicon oxide passivation layer, the carbon dioxide content in the introduced gas is 10% to 50%.
[0013] According to embodiments of this application, the thickness of the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer are both 1~10nm, and the thickness of the third intrinsic amorphous silicon oxide passivation layer is 1~5nm.
[0014] The above one or more embodiments have the following beneficial effects:
[0015] This application provides a crystalline silicon solar cell based on a molybdenum oxide (MoO) layer. By using the MoO layer as a hole transport layer, its conductivity and thin-film work function are optimized, improving hole selective transport efficiency and thin-film fabrication process adaptability. Through the first, second, and third intrinsic amorphous silicon oxide passivation layers, the dangling bonds on the N-type crystalline silicon surface are saturated, extending carrier lifetime, while the probability of oxygen diffusion from the MoO layer into the third intrinsic amorphous silicon oxide passivation layer is reduced, maintaining the high work function and other properties of the MoO layer. Ultimately, through the synergistic design of the layer structure, oxygen concentration distribution, and doping elements, the photoelectric conversion efficiency and stability of the crystalline silicon solar cell are improved, laying a reliable foundation for subsequent industrial applications. Attached Figure Description
[0016] The above-mentioned contents, other objects, features and advantages of this application will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:
[0017] Figure 1 The schematic diagram illustrates the structure of a crystalline silicon solar cell based on a molybdenum oxide layer according to an embodiment of this application. Detailed Implementation
[0018] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.
[0019] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.
[0020] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.
[0021] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).
[0022] Figure 1 The schematic diagram illustrates the structure of a crystalline silicon solar cell based on a molybdenum oxide layer according to an embodiment of this application.
[0023] like Figure 1 As shown, a crystalline silicon solar cell based on a molybdenum oxide layer includes a first transparent conductive layer, an N-type amorphous silicon layer, a first intrinsic amorphous silicon oxide passivation layer, an N-type crystalline silicon layer, a second intrinsic amorphous silicon oxide passivation layer, a third intrinsic amorphous silicon oxide passivation layer, a molybdenum oxide layer, and a second transparent conductive layer, arranged sequentially. The oxygen concentration in the first and second intrinsic amorphous silicon oxide passivation layers is lower than the oxygen concentration in the third intrinsic amorphous silicon oxide passivation layer.
[0024] The layers set sequentially mentioned here can be connected to other layers, or no other layers can be set.
[0025] In the embodiments of this application, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art.
[0026] In the embodiments of this application, the molybdenum oxide layer is a metal oxide thin film that combines high work function and selective carrier transport characteristics, and can be used as the core hole transport layer material of crystalline silicon solar cells based on molybdenum oxide layer.
[0027] In the embodiments of this application, the first intrinsic amorphous silicon oxide passivation layer, the second intrinsic amorphous silicon oxide passivation layer, and the third intrinsic amorphous silicon oxide passivation layer can all refer to amorphous silicon-based thin films using carbon dioxide as the oxygen doping source. The oxygen concentration in the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer is lower than the oxygen concentration in the third intrinsic amorphous silicon oxide passivation layer. The oxygen concentration in the first intrinsic amorphous silicon oxide passivation layer can be greater than, equal to, or less than the oxygen concentration in the second intrinsic amorphous silicon oxide passivation layer; no specific limitation is made here, and the selection can be made according to actual needs.
[0028] In the embodiments of this application, the transparent conductive layer can refer to an oxide thin film with high light transmittance and high conductivity. In the embodiments of this application, there are no special limitations on the first and second transparent conductive layers; any method, structure, and material composition of transparent conductive layers well known to those skilled in the art can be used. The first and second transparent conductive layers can be the same material or different materials, selected according to actual needs. For example, the first and / or second transparent conductive layers include, but are not limited to, one of indium tin oxide, aluminum zinc oxide, or gallium zinc oxide. The first and second transparent conductive layers possess both high light transmittance and conductivity, allowing sunlight to penetrate to the N-type crystalline silicon, which serves as the core light-absorbing layer, while also efficiently collecting charge carriers and discharging them to the outside of the battery.
[0029] In the embodiments of this application, the N-type amorphous silicon layer includes, but is not limited to, one of phosphorus-doped hydrogenated amorphous silicon layers or amorphous silicon oxide layers, which can achieve selective electron transport. The deposition method can be plasma-enhanced chemical vapor deposition. The type of crystalline silicon in the N-type crystalline silicon is not particularly limited, and those skilled in the art can choose according to actual needs. For example, the N-type crystalline silicon can be an N-type textured crystalline silicon substrate. This application does not impose any special limitations on the N-type textured crystalline silicon substrate; any N-type textured crystalline silicon substrate and texturing method well known to those skilled in the art can be used. As the core light-absorbing layer of the battery, N-type crystalline silicon generates a large number of electron-hole pairs.
[0030] According to embodiments of this application, a molybdenum oxide layer is used as a hole transport layer to optimize its conductivity and thin film work function, thereby improving hole selective transport efficiency and the adaptability to thin film fabrication processes. Through the first, second, and third intrinsic amorphous silicon oxide passivation layers, the dangling bonds on the N-type crystalline silicon surface are saturated, increasing carrier lifetime, while simultaneously reducing the probability of oxygen diffusion from the molybdenum oxide layer into the third intrinsic amorphous silicon oxide passivation layer, maintaining the high work function and other properties of the molybdenum oxide layer. Ultimately, through the synergistic design of the layer structure and oxygen concentration distribution, the photoelectric conversion efficiency and stability of the crystalline silicon solar cell are improved, laying a reliable foundation for subsequent industrial applications.
[0031] In the embodiments of this application, the thickness of the molybdenum oxide layer is 1~10 nm.
[0032] The thickness of the molybdenum oxide layer ranges from 1 to 10 nm. For example, in some embodiments of this application, the thickness of the molybdenum oxide layer can be 1 nm, 3 nm, 5 nm, 7 nm, 9 nm or 10 nm, etc., and the appropriate thickness can be selected according to actual needs.
[0033] According to the embodiments of this application, the thickness of the molybdenum oxide layer ranges from 1 to 10 nm. This helps to avoid the problems of discontinuous hole transport paths and oxygen migration blockage failure caused by excessively thin thickness, and also avoids the defects of increased photoparasitic absorption, surge in internal defect density and increased hole transport resistance caused by excessively thick thickness. It can also work synergistically with parameters such as the oxygen content during deposition to further improve the photoelectric conversion efficiency and stability of crystalline silicon solar cells.
[0034] In the embodiments of this application, the thickness of the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer is 1~10nm, and the thickness of the third intrinsic amorphous silicon oxide passivation layer is 1~5nm.
[0035] The thickness of both the first and second intrinsic amorphous silicon oxide passivation layers can be 1-10 nm, and the thickness of the third intrinsic amorphous silicon oxide passivation layer can be 1-5 nm. The thickness of the first intrinsic amorphous silicon oxide passivation layer can be greater than, equal to, or less than the thickness of the second intrinsic amorphous silicon oxide passivation layer; no specific limitation is made here, and the choice can be made according to the actual scenario. For example, in some embodiments of this application, the thickness of the first and / or second intrinsic amorphous silicon oxide passivation layers can be 1 nm, 3 nm, 5 nm, 7 nm, 9 nm, or 10 nm, etc.; the thickness of the third intrinsic amorphous silicon oxide passivation layer can be 1 nm, 3 nm, or 5 nm, etc., and the thickness that meets the requirements can be selected according to actual needs.
[0036] According to embodiments of this application, the thicknesses of the first and second intrinsic amorphous silicon oxide passivation layers are both 1-10 nm, which is beneficial for balancing passivation integrity with low light loss and low transmission resistance. The thickness of the third intrinsic amorphous silicon oxide passivation layer is 1-5 nm. While maintaining the passivation quality at the interface, this avoids hindering the transport of holes to the molybdenum oxide layer due to excessive layer thickness. This achieves an optimized balance between the passivation effect and carrier transport efficiency of crystalline silicon solar cells based on the molybdenum oxide layer, while also adapting to the controllability of industrialization processes, thereby improving the photoelectric conversion efficiency and stability of the cell.
[0037] In the embodiments of this application, the method for fabricating a crystalline silicon solar cell based on a molybdenum oxide layer includes the following steps: depositing a first intrinsic amorphous silicon oxide passivation layer and a second intrinsic amorphous silicon oxide passivation layer on the front and back surfaces of an N-type crystalline silicon cell, respectively; sequentially depositing an N-type amorphous silicon layer and a first transparent conductive layer on the side of the first intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon; and sequentially depositing a third intrinsic amorphous silicon oxide passivation layer, a molybdenum oxide layer, and a second transparent conductive layer on the side of the second intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon; wherein the oxygen concentration in the first and second intrinsic amorphous silicon oxide passivation layers is lower than the oxygen concentration in the third intrinsic amorphous silicon oxide passivation layer.
[0038] In the embodiments of this application, other layers may be provided between each layer, or no other layers may be provided.
[0039] In the embodiments of this application, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art.
[0040] In the embodiments of this application, the molybdenum oxide layer is a metal oxide thin film with both high work function and selective carrier transport characteristics, which can be used as the core hole transport layer material of crystalline silicon solar cells based on the molybdenum oxide layer.
[0041] In the embodiments of this application, the first intrinsic amorphous silicon oxide passivation layer, the second intrinsic amorphous silicon oxide passivation layer, and the third intrinsic amorphous silicon oxide passivation layer can all refer to amorphous silicon-based thin films using carbon dioxide as the oxygen doping source. The oxygen concentration in the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer is lower than the oxygen concentration in the third intrinsic amorphous silicon oxide passivation layer. The element concentration in the first intrinsic amorphous silicon oxide passivation layer can be greater than, equal to, or less than the oxygen concentration in the second intrinsic amorphous silicon oxide passivation layer; no specific limitation is made here, and it can be selected according to actual needs.
[0042] In the embodiments of this application, the N-type crystalline silicon can be cleaned first to remove the surface oil and oxide layer, then texturized, and then the following deposition steps can be performed to ensure the adhesion and interface quality between the thin film and the crystalline silicon.
[0043] Deposition refers to the process of converting gaseous precursors into thin films and attaching them to the substrate surface through specific processes such as plasma-enhanced chemical vapor deposition. It is the core operation in the preparation of solar cell thin films.
[0044] In the embodiments of this application, a first intrinsic amorphous silicon oxide passivation layer and a second intrinsic amorphous silicon oxide passivation layer are first deposited on the front and rear surfaces of the N-type crystalline silicon after cleaning and texturing. Double-sided passivation is achieved through dangling bonds on the saturated crystalline silicon surface to improve carrier lifetime and provide a low-defect interface for subsequent layer stacking. Then, an N-type amorphous silicon layer and a first transparent conductive layer are sequentially deposited on the side of the first intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon, forming an electron transport channel that facilitates the separation of photogenerated carriers and efficient electron collection. Finally, a third intrinsic amorphous silicon oxide passivation layer (further passivating the crystalline silicon surface and blocking oxygen migration from molybdenum oxide), a molybdenum oxide layer (selectively transporting holes), and a second transparent conductive layer (collecting holes) are sequentially deposited on the side of the second intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon.
[0045] According to the embodiments of this application, by first depositing passivation layers on the front and back surfaces of N-type crystalline silicon to achieve interface passivation in advance and reduce surface recombination losses, and then completing the layer-by-layer fabrication of the electron transport channel on the front surface and the hole transport channel on the back surface in the order of passivation layer, functional layer and transparent conductive layer, it is beneficial to have tight interfacial bonding and structural integrity between each layer. This not only gives full play to the passivation effect of the first and second intrinsic amorphous silicon oxide passivation layers, but also allows the third intrinsic amorphous silicon oxide passivation layer to form an efficient hole transport combination with the molybdenum oxide layer, avoiding problems such as interface defects and oxygen migration leading to a decrease in the work function of molybdenum oxide. Ultimately, this improves the carrier transport efficiency and photoelectric conversion performance of crystalline silicon solar cells based on molybdenum oxide layers, while ensuring the stability and repeatability of the fabrication process, providing reliable process support for large-scale production.
[0046] In the embodiments of this application, the molybdenum oxide layer is prepared by reactive plasma deposition.
[0047] Reactive plasma deposition (RPD) is a process that uses ionized gas to generate plasma and then uses reactive gases to initiate chemical reactions to create the desired thin film or coating. The plasma contains active particles such as electrons, ions, and free radicals. These particles collide in the gas phase, forming more active materials, which then undergo deposition reactions on the substrate surface.
[0048] According to embodiments of this application, compared to the difficulties in controlling the thickness of traditional undoped molybdenum oxide layers caused by evaporation and the potential damage to the film surface caused by sputtering, reactive plasma deposition (RPD) can precisely control the film thickness and the gas environment during the deposition process. It also reduces damage to the substrate, i.e., the third intrinsic amorphous silicon oxide passivation layer, avoiding interface structure disruption and improving the bonding stability between the passivation layer and the molybdenum oxide layer. RPD improves the conductivity of the target material and the uniformity of the film, thereby enhancing the selectivity and efficiency of hole transport. The RPD process is highly controllable, simplifying the overall fabrication process and thus improving the photoelectric conversion efficiency of crystalline silicon solar cells based on molybdenum oxide layers, laying the foundation for industrial applications.
[0049] In the embodiments of this application, the proportion of metallic molybdenum doped in the target material during the preparation of the molybdenum oxide layer is less than or equal to 10%.
[0050] In the embodiments of this application, the proportion of molybdenum doped in the target material during the preparation of the molybdenum oxide layer is less than or equal to 10%. For example, in some embodiments of this application, the proportion of molybdenum doped in the molybdenum oxide layer can be 1%, 3%, 5%, 7%, 9%, or 10%, etc.
[0051] According to the embodiments of this application, when preparing the molybdenum oxide layer, the proportion of molybdenum doped in the target material is less than or equal to 10%, which can effectively improve the conductivity of the target material, i.e., molybdenum oxide, adapt to reactive plasma deposition process, facilitate the formation of a uniform and dense film, and enhance the chemical stability of the film to suppress the migration of oxygen elements in molybdenum oxide to the third intrinsic amorphous silicon oxide passivation layer during battery annealing. This avoids destroying the original high work function characteristics of molybdenum oxide, ensures its interface compatibility with the third intrinsic amorphous silicon oxide passivation layer and hole selective transport efficiency, which is conducive to improving the photoelectric conversion efficiency of crystalline silicon solar cells based on molybdenum oxide layers, controlling the cost of the target material, and the process is easy to scale up and replicate.
[0052] In the embodiments of this application, when depositing the molybdenum oxide layer, the oxygen content in the introduced gas is greater than or equal to 20%, and the thickness of the molybdenum oxide layer is 1~10nm.
[0053] In the embodiments of this application, reactive plasma deposition technology is used to deposit a molybdenum oxide thin film on the side of the third intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon. A mixed gas containing oxygen is introduced, and the oxygen content and the final film thickness are controlled. During deposition, the volume percentage of oxygen in the mixed gas is greater than or equal to 20%, and the thickness of the deposited molybdenum oxide layer can be 1-10 nm. For example, in one embodiment of this application, the oxygen content in the introduced gas is 20%, and the thickness of the molybdenum oxide layer is 1 nm; in another embodiment, the oxygen content in the introduced gas is 30%, and the thickness of the molybdenum oxide layer is 5 nm; in yet another embodiment, the oxygen content in the introduced gas is 50%, and the thickness of the molybdenum oxide layer is 10 nm, etc. The oxygen content and the thickness of the molybdenum oxide layer can be selected according to actual needs.
[0054] According to embodiments of this application, by limiting the oxygen content in the gas introduced during the deposition of the molybdenum oxide layer to greater than or equal to 20%, a sufficient oxygen content can reduce oxygen defects in the molybdenum oxide layer, avoiding a decrease in work function due to insufficient oxygen content, thereby ensuring the selective hole transport capability. The design of a molybdenum oxide layer thickness of 1-10 nm can form a continuous and effective hole transport channel, ensuring smooth carrier transport, while avoiding excessive light parasitic absorption due to excessive thickness, or unstable transport performance due to insufficient thickness. Ultimately, this improves the photoelectric conversion efficiency of crystalline silicon solar cells while enhancing the structural stability and long-term operational reliability of the cells, providing process assurance for the industrial application of the cells.
[0055] In the embodiments of this application, the first intrinsic amorphous silicon oxide passivation layer, the second intrinsic amorphous silicon oxide passivation layer, and the third intrinsic amorphous silicon oxide passivation layer are all constructed using plasma-enhanced chemical vapor deposition.
[0056] Plasma-enhanced chemical vapor deposition (PECVD) is a method for preparing semiconductor thin films and other thin films by using glow discharge to ionize the chemical vapor in a deposition chamber and then depositing the film onto a substrate through chemical reactions. PECVD enhances the activity of the chemical vapor reactants through plasma activation, increasing the surface reaction rate. Under the influence of plasma, the gas is dissociated in the chamber, forming a highly reactive substance containing gas molecules, high-energy ions, electrons, and active free radicals. On the deposition surface, not only are conventional thermochemical reactions present, but also complex plasma-chemical reactions. The deposited film grows under the combined action of these two chemical reactions. The main methods for exciting glow discharge include radio frequency excitation, very high frequency excitation, and microwave excitation.
[0057] According to embodiments of this application, the hydrogen and oxygen contents of the first, second, and third intrinsic amorphous silicon oxide passivation layers need to be precisely controlled. Hydrogen can be used to passivate internal defects in the thin film, and PECVD technology can achieve precise composition control by adjusting gas ratios, such as the proportion of carbon dioxide. PECVD technology can deposit at temperatures below 300°C, avoiding the increase of lattice defects in crystalline silicon caused by high temperatures, while not affecting the interface characteristics of subsequent functional layers such as N-type amorphous silicon layers; it can achieve large-area thin film deposition with uniform thickness and small error, which can meet the requirements of industrial mass production; by adjusting the proportions of precursor gas, dopant gas such as carbon dioxide, and dilution gas, the oxygen and hydrogen contents of the passivation layer can be precisely controlled, which is beneficial to the balance between passivation effect and oxygen barrier function; it can also avoid thin film peeling and detachment problems in subsequent processes, improving production efficiency.
[0058] In the embodiments of this application, when depositing the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer, the proportion of carbon dioxide in the introduced gas is 1% to 10%; when depositing the third intrinsic amorphous silicon oxide passivation layer, the proportion of carbon dioxide in the introduced gas is 10% to 50%.
[0059] In the embodiments of this application, the carbon dioxide doping ratio in the gas introduced during the preparation of the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer is 1-10%, and the carbon dioxide doping ratio in the gas introduced during the preparation of the third intrinsic amorphous silicon oxide passivation layer is 10-50%. The low carbon dioxide ratio of 1-10% utilizes oxygen incorporation to make the film porous, storing more hydrogen atoms to passivate the dangling bonds on the single-crystal silicon surface. The high carbon dioxide ratio of 10-50% forms a high-oxygen-content oxygen-rich layer, effectively preventing oxygen atoms in the subsequent molybdenum oxide layer from migrating to N-type crystalline silicon, solving the problem of reduced work function of molybdenum oxide due to oxygen migration; it also improves the interfacial contact with the molybdenum oxide layer and reduces the interfacial barrier for hole transport.
[0060] According to the embodiments of this application, by differentiating the proportion of carbon dioxide in the introduced gas, the oxygen content of each passivation layer can be controlled, which is conducive to achieving precise adaptation and synergistic effect of the functions of each passivation layer, and further improving the high photoelectric conversion efficiency of crystalline silicon solar cells based on molybdenum oxide layers.
[0061] In the embodiments of this application, the thickness of the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer is 1~10nm, and the thickness of the third intrinsic amorphous silicon oxide passivation layer is 1~5nm.
[0062] The thickness of both the first and second intrinsic amorphous silicon oxide passivation layers can be 1-10 nm, and the thickness of the third intrinsic amorphous silicon oxide passivation layer can be 1-5 nm. The thickness of the first intrinsic amorphous silicon oxide passivation layer can be greater than, equal to, or less than the thickness of the second intrinsic amorphous silicon oxide passivation layer; no specific limitation is made here, and the choice can be made according to the actual scenario. For example, in some embodiments of this application, the thickness of the first and / or second intrinsic amorphous silicon oxide passivation layers can be 1 nm, 3 nm, 5 nm, 7 nm, 9 nm, or 10 nm, etc.; the thickness of the third intrinsic amorphous silicon oxide passivation layer can be 1 nm, 3 nm, or 5 nm, etc., and the appropriate thickness can be selected according to the actual scenario.
[0063] According to embodiments of this application, the thicknesses of the first and second intrinsic amorphous silicon oxide passivation layers are both 1-10 nm, which is beneficial for balancing passivation integrity and low light loss. The thickness of the third intrinsic amorphous silicon oxide passivation layer is 1-5 nm, which can meet the dual requirements of crystalline silicon surface passivation and oxygen barrier. The thinness avoids increased resistance, while the high oxygen content ensures the barrier effect, forming a synergistic effect with the high work function characteristics of the molybdenum oxide layer. Therefore, the key process parameters of the battery structure are clearly defined, carrier recombination is reduced, passivation effect is ensured, and light absorption loss or increased carrier transport resistance due to improper thickness is avoided. At the same time, it adapts to the controllability of industrialization processes, thereby improving battery stability and efficiency.
[0064] To further illustrate the technical effects of this application, the following embodiments are also provided.
[0065] Example 1
[0066] A first intrinsic amorphous silicon oxide passivation layer and a second intrinsic amorphous silicon oxide passivation layer are deposited on the front and back surfaces of the N-type crystalline silicon, respectively. An N-type amorphous silicon layer and a first transparent conductive layer are sequentially deposited on the side of the first intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon. A third intrinsic amorphous silicon oxide passivation layer, a molybdenum oxide layer, and a second transparent conductive layer are sequentially deposited on the side of the second intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon.
[0067] The first and second intrinsic amorphous silicon oxide passivation layers are 1 nm thick, and the proportion of carbon dioxide in the gas introduced during preparation is 1%. The third intrinsic amorphous silicon oxide passivation layer is 5 nm thick, and the proportion of carbon dioxide in the gas introduced during preparation is 30%. The molybdenum oxide layer is 10 nm thick, and the proportion of oxygen in the gas introduced during preparation is 30%.
[0068] Example 2
[0069] A first intrinsic amorphous silicon oxide passivation layer and a second intrinsic amorphous silicon oxide passivation layer are deposited on the front and back surfaces of the N-type crystalline silicon, respectively. An N-type amorphous silicon layer and a first transparent conductive layer are sequentially deposited on the side of the first intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon. A third intrinsic amorphous silicon oxide passivation layer, a molybdenum oxide layer, and a second transparent conductive layer are sequentially deposited on the side of the second intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon.
[0070] The first and second intrinsic amorphous silicon oxide passivation layers are 5 nm thick, and the proportion of carbon dioxide in the gas introduced during fabrication is 5%. The third intrinsic amorphous silicon oxide passivation layer is 2.5 nm thick, and the proportion of carbon dioxide in the gas introduced during fabrication is 10%. The molybdenum oxide layer is fabricated with 20% oxygen in the gas introduced during fabrication, and the film thickness is 1 nm.
[0071] Example 3
[0072] A first intrinsic amorphous silicon oxide passivation layer and a second intrinsic amorphous silicon oxide passivation layer are deposited on the front and back surfaces of the N-type crystalline silicon, respectively. An N-type amorphous silicon layer and a first transparent conductive layer are sequentially deposited on the side of the first intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon. A third intrinsic amorphous silicon oxide passivation layer, a molybdenum oxide layer, and a second transparent conductive layer are sequentially deposited on the side of the second intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon.
[0073] The first and second intrinsic amorphous silicon oxide passivation layers are 10 nm thick, and the proportion of carbon dioxide in the gas introduced during preparation is 10%. The third intrinsic amorphous silicon oxide passivation layer is 1 nm thick, and the proportion of carbon dioxide in the gas introduced during preparation is 50%. The molybdenum oxide layer is prepared by introducing oxygen in the gas with a proportion of 40%, and the film thickness is 5 nm.
[0074] Comparative Example
[0075] A first intrinsic amorphous silicon oxide passivation layer and a second intrinsic amorphous silicon oxide passivation layer are deposited on the front and back surfaces of the N-type crystalline silicon, respectively. An N-type amorphous silicon layer and a first transparent conductive layer are sequentially deposited on the side of the first intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon. A molybdenum oxide layer and a second transparent conductive layer are sequentially deposited on the side of the second intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon.
[0076] The first and second intrinsic amorphous silicon oxide passivation layers are 10 nm thick, and the proportion of carbon dioxide in the gas introduced during fabrication is 10%. The molybdenum oxide layer is fabricated with 40% oxygen in the gas introduced, and the film thickness is 5 nm.
[0077] Spectral distribution of AM1.5G, 1000W / m 2 Under standard test conditions of light intensity and 25°C, the efficiencies of the crystalline silicon solar cells prepared in the embodiments of this application are 21.35%, 21.30%, 21.82%, and 21.24%, respectively. Compared to Example 3 without the deposition of a third intrinsic amorphous silicon oxide passivation layer, the efficiency of the comparative example is slightly lower, but it still reaches 21.24%, further demonstrating that doping the target material with metallic molybdenum during the preparation of the molybdenum oxide layer improves conductivity, achieves good control of carrier transport and interface, and enhances the stability of the solar cell. The addition of the third intrinsic amorphous silicon oxide passivation layer further optimizes the efficiency, as shown in Example 3 where the efficiency reaches 21.82%. Therefore, the structural design and parameter optimization of this crystalline silicon solar cell can effectively control the cell interface characteristics, suppress the migration of oxygen from the molybdenum oxide layer to the passivation layer, reduce interface defects, ensure efficient and selective carrier transport, and thus fully leverage the synergistic effect of each functional layer, which is beneficial to improving the efficiency, performance stability, and practicality of crystalline silicon solar cells, providing solid support for their industrial application.
[0078] The above description is only a preferred embodiment of this application. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and all such improvements and modifications also fall within the protection scope of this application.
Claims
1. A crystalline silicon solar cell based on a molybdenum oxide layer, characterized in that, It includes a first transparent conductive layer, an N-type amorphous silicon layer, a first intrinsic amorphous silicon oxide passivation layer, an N-type crystalline silicon layer, a second intrinsic amorphous silicon oxide passivation layer, a third intrinsic amorphous silicon oxide passivation layer, a molybdenum oxide layer, and a second transparent conductive layer, arranged sequentially. The oxygen concentrations in the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer are both lower than the oxygen concentration in the third intrinsic amorphous silicon oxide passivation layer.
2. The crystalline silicon solar cell based on a molybdenum oxide layer according to claim 1, characterized in that, The thickness of the molybdenum oxide layer is 1~10 nm.
3. The crystalline silicon solar cell based on a molybdenum oxide layer according to claim 1, characterized in that, The thickness of the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer is 1~10nm, and the thickness of the third intrinsic amorphous silicon oxide passivation layer is 1~5nm.
4. The method for fabricating a crystalline silicon solar cell based on a molybdenum oxide layer according to any one of claims 1 to 3, characterized in that, Includes the following steps: A first intrinsic amorphous silicon oxide passivation layer and a second intrinsic amorphous silicon oxide passivation layer are deposited on the front and back surfaces of N-type crystalline silicon, respectively. An N-type amorphous silicon layer and a first transparent conductive layer are sequentially deposited on the side of the first intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon. On the side of the second intrinsic amorphous silicon oxide passivation layer away from the N-type crystalline silicon, a third intrinsic amorphous silicon oxide passivation layer, a molybdenum oxide layer, and a second transparent conductive layer are sequentially deposited. The oxygen concentrations in the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer are both lower than the oxygen concentration in the third intrinsic amorphous silicon oxide passivation layer.
5. The preparation method according to claim 4, characterized in that, The molybdenum oxide layer is prepared by reactive plasma deposition.
6. The preparation method according to claim 5, characterized in that, The molybdenum oxide layer is prepared by using a target material in which the proportion of molybdenum doped is less than or equal to 10%.
7. The preparation method according to claim 5, characterized in that, When depositing the molybdenum oxide layer, the oxygen content in the introduced gas is greater than or equal to 20%, and the thickness of the molybdenum oxide layer is 1~10 nm.
8. The preparation method according to claim 4, characterized in that, The first intrinsic amorphous silicon oxide passivation layer, the second intrinsic amorphous silicon oxide passivation layer, and the third intrinsic amorphous silicon oxide passivation layer are all achieved by plasma-enhanced chemical vapor deposition.
9. The preparation method according to claim 8, characterized in that, When depositing the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer, the carbon dioxide content in the introduced gas is 1% to 10%; when depositing the third intrinsic amorphous silicon oxide passivation layer, the carbon dioxide content in the introduced gas is 10% to 50%.
10. The preparation method according to claim 8, characterized in that, The thickness of the first intrinsic amorphous silicon oxide passivation layer and the second intrinsic amorphous silicon oxide passivation layer is 1~10nm, and the thickness of the third intrinsic amorphous silicon oxide passivation layer is 1~5nm.