Crystalline silicon solar cell and preparation method thereof

Abstract

The invention provides a crystalline silicon solar cell and a preparation method thereof. The crystalline silicon solar cell comprises an N-type crystalline silicon substrate, a first passivation layer, a second passivation layer, an N-type amorphous silicon layer, a laminated structure, a first transparent conductive layer and a second transparent conductive layer. The first passivation layer and the second passivation layer are located on opposite surfaces of the N-type crystalline silicon substrate. The N-type amorphous silicon layer is located on the first passivation layer. The laminated structure is located on the second passivation layer and comprises a first molybdenum oxide layer on the second passivation layer and a second molybdenum oxide layer on the first molybdenum oxide layer. The first transparent conductive layer is located on the N-type amorphous silicon layer, and the second transparent conductive layer is located on the second molybdenum oxide layer. The first molybdenum oxide layer is doped with molybdenum and is used as a hole transport layer. And tungsten is doped in the second molybdenum oxide layer and is used for reducing the work function of molybdenum oxide, so that the work functions of the second molybdenum oxide layer and the second transparent conductive layer are matched.

Description

TECHNICAL FIELD

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

[0002] A crystalline silicon solar cell usually selects a material with a high work function as a hole transport layer. When the silicon substrate is in contact with the material with a high work function, a band bending occurs, which can promote the tunneling of holes while blocking the transport of electrons, thereby realizing the selective transport of holes. Molybdenum oxide, tungsten oxide and vanadium oxide are often used as the hole transport layer of the crystalline silicon solar cell due to their wide band gap and high work function. However, the above-mentioned metal oxide thin film is usually prepared by evaporation or sputtering. The thickness of the thin film is not easy to control in the evaporation process, and the sputtering process will cause great damage to the surface of the thin film, thereby reducing the photoelectric conversion efficiency of the crystalline silicon solar cell. SUMMARY

[0003] In view of the above problems, the present disclosure provides a crystalline silicon solar cell and a preparation method thereof.

[0004] According to a first aspect of the present disclosure, a crystalline silicon solar cell is provided. The crystalline silicon solar cell comprises an N-type crystalline silicon substrate, a first passivation layer, a second passivation layer, an N-type amorphous silicon layer, a stack structure, a first transparent conductive layer and a second transparent conductive layer. The first passivation layer and the second passivation layer are located on opposite surfaces of the N-type crystalline silicon substrate. The N-type amorphous silicon layer is located on the first passivation layer. The stack structure is located on the second passivation layer, and the stack structure comprises a first molybdenum oxide layer on the second passivation layer and a second molybdenum oxide layer on the first molybdenum oxide layer. The first transparent conductive layer is located on the N-type amorphous silicon layer, and the second transparent conductive layer is located on the second molybdenum oxide layer. The first molybdenum oxide layer is doped with molybdenum as a hole transport layer, and the second molybdenum oxide layer is doped with tungsten to reduce the work function of molybdenum, so as to match the work function between the second molybdenum oxide layer and the second transparent conductive layer.

[0005] According to an embodiment of the present disclosure, the first molybdenum oxide layer and the second molybdenum oxide layer in the stack structure are aligned in a vertical direction, and the thickness of the first molybdenum oxide layer is greater than the thickness of the second molybdenum oxide layer.

[0006] According to an embodiment of the present disclosure, the doping proportion of tungsten in the second molybdenum oxide layer is determined according to the work function of the second transparent conductive layer, so as to match the work function between the second molybdenum oxide layer and the second transparent conductive layer.

[0007] According to an embodiment of the present disclosure, the N-type crystalline silicon substrate comprises N-type textured crystalline silicon. The N-type amorphous silicon layer comprises a phosphorus-doped amorphous silicon thin film.

[0008] According to an embodiment of the present disclosure, the first passivation layer and the second passivation layer comprise intrinsic amorphous silicon, and the first transparent conductive layer and the second transparent conductive layer comprise any one of indium oxide-based, fluorine-doped tin oxide, and aluminum-doped zinc oxide.

[0009] According to a second aspect of the present disclosure, a method for manufacturing a crystalline silicon solar cell is provided. The method comprises: forming a first passivation layer and a second passivation layer on opposite surfaces of an N-type crystalline silicon substrate; forming an N-type amorphous silicon layer on the first passivation layer; depositing a stack structure on the second passivation layer, the stack structure comprising a first molybdenum oxide layer on the second passivation layer and a second molybdenum oxide layer on the first molybdenum oxide layer; and forming a first transparent conductive layer and a second transparent conductive layer on the N-type amorphous silicon layer and the second molybdenum oxide layer, respectively. The first molybdenum oxide layer is doped with molybdenum and serves as a hole transport layer. The second molybdenum oxide layer is doped with tungsten to lower the work function of molybdenum so as to match the work function between the second molybdenum oxide layer and the second transparent conductive layer.

[0010] According to an embodiment of the present disclosure, the first molybdenum oxide layer and the second molybdenum oxide layer are deposited on the second passivation layer by a reactive plasma deposition method.

[0011] According to an embodiment of the present disclosure, the first molybdenum oxide layer and the second molybdenum oxide layer are deposited on the second passivation layer by a reactive plasma deposition method, comprising:

[0012] The oxygen flow ratio in the gas introduced during the reactive plasma deposition of the first molybdenum oxide layer and the second molybdenum oxide layer is 20% to 50%.

[0013] According to an embodiment of the present disclosure, the doping ratio of molybdenum in the target material during the deposition of the first molybdenum oxide layer is less than or equal to 10%. The doping ratio of tungsten in the target material during the deposition of the second molybdenum oxide layer is less than or equal to 5%. The deposition thickness of the first molybdenum oxide layer and the second molybdenum oxide layer comprises 1 nm to 10 nm.

[0014] According to an embodiment of the present disclosure, the first molybdenum oxide layer and the second molybdenum oxide layer deposited on the second passivation layer are aligned in the vertical direction, and the thickness of the first molybdenum oxide layer is greater than the thickness of the second molybdenum oxide layer.

[0015] According to an embodiment of the present disclosure, a crystalline silicon solar cell is provided. The crystalline silicon solar cell is provided with a stack structure comprising a first molybdenum oxide layer and a second molybdenum oxide layer on a second passivation layer, the first molybdenum oxide layer is doped with molybdenum, and the second molybdenum oxide layer is doped with tungsten. The first molybdenum oxide layer has a high work function and serves as a hole transport layer, which can enhance the transmission efficiency of holes. The second molybdenum oxide layer can lower the work function of molybdenum so as to match the work function between the second molybdenum oxide layer and the second transparent dielectric layer, thereby improving the interface contact properties between the second molybdenum oxide layer and the second transparent dielectric layer. In this way, the photoelectric conversion efficiency of the crystalline silicon solar cell can be improved. Attached Figure Description

[0016] The foregoing contents, as well as other objects, features, and advantages of this disclosure, will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0017] Figure 1 A schematic diagram of the structure of a crystalline silicon solar cell according to an embodiment of the present disclosure is shown.

[0018] Figure 2 A flowchart illustrating a method for fabricating a crystalline silicon solar cell according to an embodiment of the present disclosure is shown. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0020] The endpoints and any values ​​of the ranges disclosed in this disclosure are not limited to the precise ranges or values, and such ranges or values ​​should be understood to include values ​​close to such ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this disclosure.

[0021] 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.

[0022] 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.

[0023] In the description of this disclosure, it should be understood that the terms "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the subsystem or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0024] Similarly, to simplify this disclosure and aid in understanding one or more of the various aspects of the disclosure, in the above description of exemplary embodiments of the present disclosure, various features of the present disclosure are sometimes grouped together in a single embodiment, figure, or description thereof. The use of terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refers to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present disclosure. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0025] The hole transport layer in crystalline silicon solar cells often requires a high work function, causing band bending at the interface between the silicon substrate and the hole transport layer. Electrons are blocked by the higher potential barrier formed by the band bending, thus achieving selective hole transport. In related examples, boron-doped p-type silicon-based thin films can be used as the material for the hole transport layer. However, p-type silicon-based thin films have a small band gap, are prone to parasitic absorption, and require the use of toxic and harmful gases during their fabrication. Currently, hole transport layer materials typically employ molybdenum oxide, tungsten oxide, or vanadium oxide, which have wider band gaps and higher work functions. These materials are usually prepared using evaporation or sputtering methods. However, the film thickness is difficult to control during evaporation, and sputtering can cause significant damage to the film surface, thereby reducing the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0026] In view of this, embodiments of the present disclosure provide a crystalline silicon solar cell and a method for fabricating the same. This crystalline silicon solar cell employs a stacked structure of a first molybdenum oxide layer doped with molybdenum and a second molybdenum oxide layer doped with tungsten, achieving a good balance between improving carrier transport efficiency and enhancing interfacial contact characteristics, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell. Furthermore, since the doping of the molybdenum oxide target improves its conductivity, the first and second molybdenum oxide layers can be formed using reactive plasma deposition, reducing damage to the thin film and mitigating problems such as equipment malfunction during deposition due to the poor conductivity of molybdenum oxide.

[0027] Figure 1 A schematic diagram of the structure of a crystalline silicon solar cell according to an embodiment of the present disclosure is shown.

[0028] like Figure 1 As shown, the crystalline silicon solar cell of this disclosure embodiment may include an N-type crystalline silicon substrate, a first passivation layer, a second passivation layer, an N-type amorphous silicon layer, a stacked structure, a first transparent conductive layer, and a second transparent conductive layer.

[0029] The first passivation layer and the second passivation layer can be located on opposite surfaces of an N-type crystalline silicon substrate, such as... Figure 1 On opposite surfaces in the vertical direction within the plane of the paper. The N-type crystalline silicon substrate, as the light-absorbing layer of a solar cell, can generate a large number of electron-hole pairs, which is the main source of charge carriers in a crystalline silicon solar cell. The type of N-type crystalline silicon substrate disclosed herein can be set according to actual needs, and is not specifically limited in this disclosure. The first passivation layer and the second passivation layer can passivate the dangling bonds on the surface of the N-type crystalline silicon substrate, reducing the recombination loss of charge carriers on the substrate surface. The first passivation layer and the second passivation layer disclosed herein can be set according to actual needs, and are not specifically limited in this disclosure.

[0030] An N-type amorphous silicon layer can be located on the first passivation layer. A stacked structure can be located on the second passivation layer. This stacked structure can be a hole transport layer and may include a first molybdenum oxide layer on the second passivation layer and a second molybdenum oxide layer on the first molybdenum oxide layer. The first molybdenum oxide layer may be doped with molybdenum to serve as the host of the hole transport layer. The second molybdenum oxide layer may be doped with tungsten to reduce the work function of the molybdenum oxide, thereby matching the work function between the second molybdenum oxide layer and the second transparent conductive layer.

[0031] The first transparent conductive layer can be located on the N-type amorphous silicon layer, and the second transparent conductive layer can be located on the second molybdenum oxide layer. The first and second transparent conductive layers not only serve as electrodes but also allow most of the incident light to pass through, reducing surface light reflection and increasing light absorption. The first and second transparent conductive layers of this disclosure can be configured according to actual needs, and no specific limitations are made in this disclosure.

[0032] According to embodiments of this disclosure, a crystalline silicon solar cell is provided. This crystalline silicon solar cell has a stacked structure comprising a first molybdenum oxide layer and a second molybdenum oxide layer disposed on a second passivation layer. The first molybdenum oxide layer is doped with molybdenum, and the second molybdenum oxide layer is doped with tungsten. The molybdenum-doped first molybdenum oxide layer can have a high work function, serving as the main body of the hole transport layer and enhancing hole transport efficiency. The tungsten-doped second molybdenum oxide layer can reduce the work function of molybdenum oxide, matching the work function of the second molybdenum oxide layer with that of the second transparent dielectric layer, thereby improving the interfacial contact characteristics between the second molybdenum oxide layer and the second transparent conductive layer. Thus, the photoelectric conversion efficiency of the crystalline silicon solar cell can be improved.

[0033] Continue to refer to Figure 1In the stacked structure, the first molybdenum oxide layer and the second molybdenum oxide layer can be aligned in the vertical direction. In the example, the thickness of the first molybdenum oxide layer and the thickness of the second molybdenum oxide layer can include 1 nm to 10 nm, such as 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, etc., and the thickness of the first molybdenum oxide layer can be greater than the thickness of the second molybdenum oxide layer.

[0034] According to embodiments of this disclosure, aligning the first molybdenum oxide layer and the second molybdenum oxide layer in the vertical direction can increase the photoelectric conversion area of ​​the crystalline silicon solar cell and improve cell efficiency. The first molybdenum oxide layer, as a key structure for hole transport, is one of the core components for achieving photoelectric conversion. The second molybdenum oxide layer, as a control structure for regulating the work function matching between the first and second transparent dielectric layers, is implemented while ensuring hole transport performance. Therefore, setting the thickness of the first molybdenum oxide layer to be greater than the thickness of the second molybdenum oxide layer allows for good control between carrier transport performance and good interface contact.

[0035] In some specific embodiments, the tungsten doping ratio in the second molybdenum oxide layer can be determined based on the work function of the second transparent conductive layer to match the work functions of the second molybdenum oxide layer and the second transparent conductive layer. In the example, the molybdenum oxide material has a higher work function than the second transparent conductive layer, which will form a higher potential barrier at the interface and reduce the selective transport performance of holes.

[0036] According to embodiments of this disclosure, by doping tungsten into the second molybdenum oxide layer, the work function of the molybdenum oxide material can be reduced, so that the work function of the second molybdenum oxide layer is between that of the first molybdenum oxide layer and the second transparent conductive layer, thereby matching the work functions of the second molybdenum oxide layer and the second transparent conductive layer, improving the interfacial contact characteristics between the two and enhancing battery performance.

[0037] In some specific embodiments, the N-type crystalline silicon substrate may include N-type texturized crystalline silicon. N-type texturized crystalline silicon is N-type crystalline silicon with a textured surface formed on the surface of crystalline silicon. The N-type amorphous silicon layer may include a proportion of phosphorus-doped amorphous silicon thin films.

[0038] According to embodiments of this disclosure, forming a textured structure on the surface of N-type crystalline silicon can reduce light reflection, increase the propagation path and absorption efficiency of incident light within the crystalline silicon, thereby improving photoelectric conversion efficiency.

[0039] In some specific embodiments, the first passivation layer and the second passivation layer may comprise intrinsic amorphous silicon. The first transparent conductive layer and the second transparent conductive layer may comprise any one of indium oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide.

[0040] According to embodiments of this disclosure, the first passivation layer and the second passivation layer can passivate the dangling bonds on the surface of the N-type crystalline silicon substrate, reducing the recombination loss of charge carriers on the surface of the N-type crystalline silicon substrate. The first transparent conductive layer and the second transparent conductive layer can not only serve as electrodes, but also allow most of the incident light to pass through, reducing light reflection on the surface and increasing light absorption.

[0041] Figure 2 The flowchart illustrating a method for fabricating a crystalline silicon solar cell according to an embodiment of the present disclosure is shown. It should be noted that other functional layers, such as back surface fields, light-trapping layers, etc., may also be provided between the layers in the embodiments of the present disclosure, and will not be described separately therein.

[0042] like Figure 2 As shown, the preparation method of this embodiment may include operations S210 to S240.

[0043] In operation S210, a first passivation layer and a second passivation layer are formed on opposite surfaces of an N-type crystalline silicon substrate.

[0044] According to embodiments of this disclosure, in operation S210, the N-type crystalline silicon substrate can be N-type texturized crystalline silicon. The texturing method and process of the N-type texturized crystalline silicon can be specifically set according to actual needs and process parameters well known to those skilled in the art, and this disclosure does not limit them. A first passivation layer and a second passivation layer can be formed on the N-type crystalline silicon substrate using plasma-enhanced chemical vapor deposition. The process parameters for forming the first passivation layer and the second passivation layer in this disclosure can be specifically set according to actual needs and process parameters well known to those skilled in the art, and this disclosure does not limit them.

[0045] In operation S220, an N-type amorphous silicon layer is formed on the first passivation layer.

[0046] According to embodiments of this disclosure, in operation S220, an N-type amorphous silicon layer can be formed on the first passivation layer using plasma-enhanced chemical vapor deposition. The process parameters for forming the N-type amorphous silicon layer in this disclosure can be specifically set according to actual needs and process parameters well known to those skilled in the art, and are not limited herein.

[0047] In operation S230, a stacked structure is deposited on the second passivation layer, the stacked structure including a first molybdenum oxide layer on the second passivation layer and a second molybdenum oxide layer on the first molybdenum oxide layer.

[0048] According to an embodiment of this disclosure, in operation S230, the first molybdenum oxide layer is doped with molybdenum to serve as the host of the hole transport layer. The second molybdenum oxide layer is doped with tungsten to reduce the work function of the molybdenum oxide, thereby matching the work function between the second molybdenum oxide layer and the second transparent conductive layer.

[0049] In a specific embodiment, a first molybdenum oxide layer and a second molybdenum oxide layer can be deposited on the second passivation layer using reactive plasma deposition.

[0050] In operation S240, a first transparent conductive layer and a second transparent conductive layer are formed on the N-type amorphous silicon layer and the second molybdenum oxide layer, respectively.

[0051] According to embodiments of this disclosure, in operation S240, a first transparent conductive layer and a second transparent conductive layer can be formed using reactive plasma deposition. The process parameters for forming the first and second transparent conductive layers in this disclosure can be specifically set according to actual needs and process parameters well known to those skilled in the art, and are not limited herein.

[0052] According to embodiments of this disclosure, due to the doping of the stacked structure, a first molybdenum oxide layer and a second molybdenum oxide layer can be formed by reactive plasma deposition. This not only reduces damage to the thin film, but also allows for the preparation of a thin film of superior quality at low temperatures. In addition, it reduces problems such as equipment malfunction during the deposition process due to the poor conductivity of molybdenum oxide.

[0053] In some specific embodiments, the deposition of a first molybdenum oxide layer and a second molybdenum oxide layer on the second passivation layer using reactive plasma deposition may include: the oxygen flow rate in the gas introduced during reactive plasma deposition of the first and second molybdenum oxide layers is 20% to 50%. For example, it can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc.

[0054] According to embodiments of this disclosure, setting the oxygen flow rate during reactive plasma deposition can not only reduce the impact of insufficient oxygen flow rate on the conductivity of the material due to the formation of oxygen vacancies or molybdenum suboxide, but also reduce the reduction in film uniformity caused by excessive oxygen flow rate, thereby improving the electrical performance and stability of crystalline silicon solar cells.

[0055] In some specific embodiments, the molybdenum doping ratio in the target material during the deposition of the first molybdenum oxide layer can be less than or equal to 10%, for example, it can be 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, etc. The tungsten doping ratio in the target material during the deposition of the second molybdenum oxide layer can be less than or equal to 5%, for example, it can be 5%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, etc. The deposition thickness of the first and second molybdenum oxide layers can include 1 nm to 10 nm, for example, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, etc.

[0056] In some specific embodiments, the first molybdenum oxide layer and the second molybdenum oxide layer deposited on the second passivation layer are aligned in the vertical direction, and the thickness of the first molybdenum oxide layer is greater than the thickness of the second molybdenum oxide layer. For example, the thickness of the first molybdenum oxide layer is 5 nm and the thickness of the second molybdenum oxide layer is 2 nm.

[0057] According to embodiments of this disclosure, a stacked structure of a first molybdenum oxide layer doped with molybdenum and a second molybdenum oxide layer doped with tungsten is formed by reactive plasma deposition, which achieves good control between improving carrier transport efficiency and improving interfacial contact characteristics, thereby improving the photoelectric conversion efficiency of crystalline silicon solar cells.

[0058] The following description, in conjunction with the embodiments, illustrates the preparation method of the crystalline silicon solar cell of this disclosure, in order to further explain the technical effects of the embodiments of this disclosure.

[0059] In some embodiments, firstly, intrinsic amorphous silicon is deposited on the upper and lower surfaces of an N-type textured crystalline silicon substrate to form a first passivation layer and a second passivation layer, respectively, and an N-type amorphous silicon layer is deposited on the first passivation layer. Secondly, a first transparent conductive layer is deposited on the N-type amorphous silicon. Next, a first molybdenum oxide layer with a thickness of 1 nm is deposited on the second passivation layer, wherein the molybdenum doping ratio in the first molybdenum oxide layer is set to 10%; a second molybdenum oxide layer with a thickness of 10 nm is deposited on the first molybdenum oxide layer, wherein the tungsten doping ratio in the second molybdenum oxide layer is set to 1%; the oxygen flow rate in the gas introduced during reactive plasma deposition of the first and second molybdenum oxide layers is 20%. Finally, a second transparent conductive layer is deposited on the surface of the second molybdenum oxide layer, thereby obtaining the crystalline silicon solar cell of this disclosure.

[0060] In some embodiments, the preparation method described in the above embodiments is used, except that a first molybdenum oxide layer with a thickness of 10 nm is deposited on the second passivation layer, and the molybdenum doping ratio in the target material is set to 1% during the deposition of the first molybdenum oxide layer; a second molybdenum oxide layer with a thickness of 1 nm is deposited on the first molybdenum oxide layer, and the tungsten doping ratio in the target material is set to 5% during the deposition of the second molybdenum oxide layer. The oxygen flow rate in the gas introduced during reactive plasma deposition of the first and second molybdenum oxide layers is 40%.

[0061] In some embodiments, the preparation method described in the above embodiments is used, except that a first molybdenum oxide layer with a thickness of 5 nm is deposited on the second passivation layer, and the molybdenum doping ratio in the target material is set to 5% during the deposition of the first molybdenum oxide layer; a second molybdenum oxide layer with a thickness of 5 nm is deposited on the first molybdenum oxide layer, and the tungsten doping ratio in the target material is set to 2.5% during the deposition of the second molybdenum oxide layer. When the first and second molybdenum oxide layers are prepared by reactive plasma deposition, the oxygen flow rate in the introduced gas accounts for 30%.

[0062] In some embodiments, the preparation method described in the above embodiments is used, except that a first molybdenum oxide layer with a thickness of 4 nm is deposited on the second passivation layer, and the molybdenum doping ratio in the target material is set to 5% during the deposition of the first molybdenum oxide layer; a second molybdenum oxide layer with a thickness of 2 nm is deposited on the first molybdenum oxide layer, and the tungsten doping ratio in the target material is set to 2.5% during the deposition of the second molybdenum oxide layer. When the first and second molybdenum oxide layers are prepared by reactive plasma deposition, the oxygen flow rate in the introduced gas is 50%.

[0063] To further describe the performance of the crystalline silicon solar cells prepared in the above embodiments, the photoelectric conversion efficiency of the crystalline silicon solar cells in the above embodiments was tested. The test was conducted under a spectral distribution of AM (Air Mass) 1.5G and an irradiance of 1000 W / m². 2 Under test conditions of 25 °C, the photoelectric conversion efficiencies of the crystalline silicon solar cells in the above embodiments are 18.82%, 19.97%, 19.11%, and 20.13%, respectively.

[0064] Those skilled in the art will understand that the features described in the various embodiments of this disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments of this disclosure can be combined and / or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0065] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A crystalline silicon solar cell, characterized in that, include: N-type crystalline silicon substrate; The first passivation layer and the second passivation layer on opposite surfaces of the N-type crystalline silicon substrate; The N-type amorphous silicon layer on the first passivation layer; The stacked structure on the second passivation layer includes a first molybdenum oxide layer on the second passivation layer and a second molybdenum oxide layer on the first molybdenum oxide layer; The first transparent conductive layer on the N-type amorphous silicon layer and the second transparent conductive layer on the second molybdenum oxide layer; The first molybdenum oxide layer is doped with molybdenum to serve as a hole transport layer, and the second molybdenum oxide layer is doped with tungsten to reduce the work function of the molybdenum oxide layer so that the work functions of the second molybdenum oxide layer and the second transparent conductive layer are matched.

2. The crystalline silicon solar cell according to claim 1, characterized in that, The first molybdenum oxide layer and the second molybdenum oxide layer in the stacked structure are aligned in the vertical direction, and the thickness of the first molybdenum oxide layer is greater than the thickness of the second molybdenum oxide layer.

3. The crystalline silicon solar cell according to claim 1, characterized in that, The doping ratio of tungsten in the second molybdenum oxide layer is determined based on the work function of the second transparent conductive layer, so as to match the work function between the second molybdenum oxide layer and the second transparent conductive layer.

4. The crystalline silicon solar cell according to any one of claims 1 to 3, characterized in that, The N-type crystalline silicon substrate includes N-type texturized crystalline silicon; The N-type amorphous silicon layer includes a phosphorus-doped amorphous silicon thin film.

5. The crystalline silicon solar cell according to any one of claims 1 to 3, characterized in that, The first passivation layer and the second passivation layer comprise intrinsic amorphous silicon; The first transparent conductive layer and the second transparent conductive layer include any one of indium oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide.

6. A method for preparing a crystalline silicon solar cell, characterized in that, include: A first passivation layer and a second passivation layer are formed on opposite surfaces of an N-type crystalline silicon substrate; An N-type amorphous silicon layer is formed on the first passivation layer; A stacked structure is deposited on the second passivation layer, the stacked structure comprising a first molybdenum oxide layer on the second passivation layer and a second molybdenum oxide layer on the first molybdenum oxide layer; A first transparent conductive layer and a second transparent conductive layer are deposited on the N-type amorphous silicon layer and the second molybdenum oxide layer, respectively. The first molybdenum oxide layer is doped with molybdenum to serve as a hole transport layer, and the second molybdenum oxide layer is doped with tungsten to reduce the work function of the molybdenum oxide layer so that the work functions of the second molybdenum oxide layer and the second transparent conductive layer are matched.

7. The preparation method according to claim 6, characterized in that, The first molybdenum oxide layer and the second molybdenum oxide layer are deposited on the second passivation layer using reactive plasma deposition.

8. The preparation method according to claim 7, characterized in that, The method of depositing the first molybdenum oxide layer and the second molybdenum oxide layer on the second passivation layer using reactive plasma deposition includes: The first and second molybdenum oxide layers were deposited using reactive plasma deposition in which the oxygen flow rate in the gas was 20% to 50%.

9. The preparation method according to any one of claims 6 to 8, characterized in that, The molybdenum doping ratio in the target material during the deposition of the first molybdenum oxide layer is less than or equal to 10%. The second molybdenum oxide layer has a tungsten doping ratio of less than or equal to 5% in the target material during deposition; The deposition thickness of the first molybdenum oxide layer and the second molybdenum oxide layer ranges from 1 nm to 10 nm.

10. The preparation method according to any one of claims 6 to 8, characterized in that, The first molybdenum oxide layer and the second molybdenum oxide layer deposited on the second passivation layer are aligned in the vertical direction, and the thickness of the first molybdenum oxide layer is greater than the thickness of the second molybdenum oxide layer.

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