Solar heterojunction cell

Abstract

The utility model provides a solar heterojunction cell. The solar heterojunction cell comprises a silicon substrate, a first doped crystalline silicon layer, a transparent conductive composite film layer and a first electrode. The first doped crystalline silicon layer and the transparent conductive composite film layer are sequentially stacked on the front face of the silicon substrate. The transparent conductive composite film layer comprises a VTTO material layer and an ITO material layer. The VTTO material layer is disposed toward the silicon substrate. And the ITO material layer is arranged back to back on to the silicon substrate. The VTTO material layer and the ITO material layer have the same material component, and the indium content of the VTTO material layer is greater than that of the ITO material layer. The first electrode is arranged on the ITO material layer. According to the solar heterojunction cell provided by the invention, the carrier mobility and the conductivity are improved, and relatively high contact force between the transparent conductive composite film layer and the first electrode is ensured, so that the first electrode is not easy to fall off, and the reliability of the cell is improved.

Description

Technical Field

[0001] The present application relates to the technical field of photovoltaic cells, and more particularly, to a heterojunction solar cell. Background Art

[0002] A heterojunction solar cell (HJT cell) is an N-type double-sided cell, which has the advantages of simple process flow, high efficiency, low temperature coefficient, low temperature throughout the process, and low industrialization energy consumption. It also has no light-induced degradation (LID degradation) and photo-thermal degradation (LeTID degradation) problems. The heterojunction solar cell also has many advantages such as being suitable for thinning and having good low-light response. The heterojunction solar cell uses crystalline silicon as the absorption layer to absorb photons to generate electron-hole pairs. The holes pass through the intrinsic amorphous silicon passivation layer or the intrinsic amorphous silicon passivation stack and the P-type doped crystalline silicon layer and enter the metal electrode for hole collection. The electrons pass through the intrinsic amorphous silicon passivation layer or the intrinsic amorphous silicon passivation stack and the N-type doped crystalline silicon layer and enter the metal electrode for electron collection, thereby forming a photocurrent.

[0003] In order to improve the transport ability of electrons and holes transported from the N-type doped crystalline silicon layer and the P-type doped crystalline silicon layer, a transparent conductive oxide film (TCO layer) is usually integrally covered on the N-type doped crystalline silicon layer and the P-type doped crystalline silicon layer respectively. Existing heterojunction solar cells usually use indium oxide (In2O3) material to prepare the TCO layer. Although it has good optoelectronic properties and can prepare high-efficiency heterojunction solar cells, indium is a rare metal with limited reserves and high price. The cost of the indium-based TCO layer accounts for about 10% - 15% of the non-silicon cost of the heterojunction solar cell, second only to low-temperature silver paste. The existing indium-free materials suitable for use as the TCO layer mainly include ZnO, AZO, GZO, GAZO, and SnO2. However, compared with the indium-based TCO layer, these indium-free TCO layers have certain disadvantages in terms of optical and / or electrical properties, and there are also problems in terms of reliability.

[0004] Therefore, how to develop a transparent conductive oxide film with excellent optical properties, excellent electrical properties and meeting the reliability of heterojunction solar cells has become an urgent problem to be solved in the industrialization process of heterojunction solar cells. Utility Model Content

[0005] The present application provides a heterojunction solar cell, which can not only improve the carrier mobility and conductivity, but also improve the reliability of the battery.

[0006] A heterojunction solar cell includes: a silicon substrate, a first doped crystalline silicon layer, a transparent conductive composite film layer, and a first electrode;

[0007] The first doped crystalline silicon layer and the transparent conductive composite film layer are sequentially stacked on the front side of the silicon substrate;

[0008] The transparent conductive composite film layer includes a VTTO material layer and an ITO material layer; the VTTO material layer faces the silicon substrate; the ITO material layer faces away from the silicon substrate; the material components of the VTTO material layer and the ITO material layer are the same, and the indium content of the VTTO material layer is greater than that of the ITO material layer;

[0009] The first electrode is disposed on the ITO material layer.

[0010] Optionally, the transparent conductive composite film layer further includes a penetration layer;

[0011] The penetration layer is disposed between the VTTO material layer and the ITO material layer, and the penetration layer is formed by the mutual penetration of the VTTO material and the ITO material.

[0012] Optionally, the solar heterojunction cell further includes a first transparent conductive film layer;

[0013] The first transparent conductive film layer is laminated between the first doped crystalline silicon layer and the transparent conductive composite film layer, and the material of the first transparent conductive film layer is the same as that of the VTTO material layer.

[0014] Optionally, the solar heterojunction cell further includes a second transparent conductive film layer;

[0015] The second transparent conductive film layer is laminated between the first transparent conductive film layer and the transparent conductive composite film layer; the second transparent conductive film layer includes a fluorine-doped tin oxide layer.

[0016] Optionally, the first electrode is a composite metal electrode, including a first metal and a second metal; the materials of the first metal and the second metal are different, and both the first metal and the second metal are in contact with the ITO material layer.

[0017] Optionally, the solar heterojunction cell further includes a second doped crystalline silicon layer, a third transparent conductive film layer, and a fourth transparent conductive film layer that are sequentially laminated on the back surface of the silicon substrate;

[0018] The material of the third transparent conductive film layer is the same as that of the VTTO material layer, and the material of the fourth transparent conductive film layer is the same as that of the ITO material layer.

[0019] Optionally, the solar heterojunction cell further includes a transparent conductive sandwich film layer;

[0020] The transparent conductive sandwich film layer is laminated between the third transparent conductive film layer and the fourth transparent conductive film layer; the transparent conductive sandwich film layer includes a first non-indium material layer, a second non-indium material layer, and a sandwich material layer;

[0021] The materials of the first non-indium material layer and the second non-indium material layer are different; the sandwich material layer is laminated between the first non-indium material layer and the second non-indium material layer, and the sandwich material layer includes a fluorine-doped tin oxide layer.

[0022] Optionally, the first non-indium material layer includes an FTO material layer, and the tin content of the FTO material layer is less than the tin content of the fluorine-doped tin oxide layer; the second non-indium material layer includes an AZO material layer.

[0023] Optionally, the second doped crystalline silicon layer includes a P-type doped crystalline silicon layer.

[0024] Optionally, the solar heterojunction battery further includes a second electrode connected to the fourth transparent conductive film layer.

[0025] The present application provides a solar heterojunction battery, which not only improves the carrier mobility and conductivity, but also ensures a high contact force between the transparent conductive composite film layer and the first electrode, making the first electrode not easy to fall off and improving the reliability of the battery. Description of the Drawings

[0026] Figure 1 It is a schematic structural diagram of a solar heterojunction battery shown in an exemplary embodiment of the present application.

[0027] Figure 2 It is a schematic structural diagram of a coating device shown in an exemplary embodiment of the present application.

[0028] Reference numerals: 1, silicon substrate; 2, first doped crystalline silicon layer; 3, transparent conductive composite film layer; 31, ITO material layer; 32, VTTO material layer; 33, permeation layer; 4, first transparent conductive film layer; 5, second transparent conductive film layer; 6, second doped crystalline silicon layer; 7, third transparent conductive film layer; 8, fourth transparent conductive film layer; 9, transparent conductive sandwich film layer; 91, first indium-free material layer; 92, second indium-free material layer; 93, sandwich material layer; 10a, first electrode; 10b, second electrode; 20, first physical vapor deposition chamber; 21, second physical vapor deposition chamber; 22, third physical vapor deposition chamber; 23, isolation chamber; 24, fourth physical vapor deposition chamber; 25, fifth physical vapor deposition chamber; 251, first sub-deposition chamber; 252, second sub-deposition chamber; 253, third sub-deposition chamber; 254, fourth sub-deposition chamber; 26, sixth physical vapor deposition chamber; 27, front transition chamber; 271, first transition cavity; 272, first heating cavity; 273, second heating cavity; 28, rear transition chamber; 281, first cooling cavity; 282, second cooling cavity; 283, second transition cavity; A, mechanical pump; B, Roots pump; C, molecular pump; D, cold trap; E, heating module; F, residual gas analysis and monitoring component (RGA). Detailed implementation manners

[0029] The technical solutions of the present application will be described in detail below with reference to the accompanying drawings. In each embodiment of the present application, terms such as "first" and "second" are only used for the purpose of convenient description and cannot be construed as indicating or implying relative importance.

[0030] Please refer to Figure 1 , the present application provides a solar heterojunction cell, including a silicon substrate 1, a first doped crystalline silicon layer 2, a transparent conductive composite film layer 3, and a first electrode 10a. The first doped crystalline silicon layer 2 and the transparent conductive composite film layer 3 are sequentially stacked on the front side of the silicon substrate 1. The transparent conductive composite film layer 3 includes a VTTO material layer 32 and an ITO material layer 31. The VTTO material layer 32 faces the silicon substrate 1. The ITO material layer 31 faces away from the silicon substrate 1. The VTTO material layer 32 and the ITO material layer 31 have the same material composition, and the indium content of the VTTO material layer 32 is greater than that of the ITO material layer 31. The first electrode 10a is disposed on the ITO material layer 31.

[0031] It should be noted that both the ITO material and the VTTO material are existing known materials. This application does not propose improvements to the materials themselves, but only applies the known materials to the transparent conductive composite film layer 3 with a structure. Among them, the ITO material refers to indium tin oxide (In2O3:Sn), and the mass ratio of indium oxide to tin is less than or equal to 97:3. The VTTO material refers to indium tin oxide (In2O3:Sn), and the mass ratio of indium oxide to tin is greater than or equal to 99:1.

[0032] Since the VTTO material layer 32 has a relatively high indium content and better crystal structure stability, it has a higher compatibility with the doped crystalline silicon layer. When a transparent conductive thin film is made only of the VTTO material with a relatively high indium content, the carrier mobility and conductivity can be improved, and a relatively large short-circuit current (Isc) can be theoretically shown. However, in the actual production process, it is measured that the value of the short-circuit current (Isc) actually delivered by the electrode in contact with the transparent conductive thin film is relatively small, which is quite different from the theory. Through research, it is found that the adhesion ability of the VTTO material with a relatively high indium content is low, resulting in a poor contact force in the area where the VTTO material contacts the electrode, and it is easy to generate gaps, which hinders the current transmission process, resulting in a significant reduction in the short-circuit current (Isc) on the actual test electrode side.

[0033] Therefore, in this application, the transparent conductive thin film is prepared into the transparent conductive composite film layer 3, so that the VTTO material layer 32 with a relatively high indium content in the transparent conductive composite film layer 3 cooperates with the first doped crystalline silicon layer 2, which can improve the carrier mobility and conductivity, effectively improve the short-circuit current (Isc) and fill factor (FF), and has excellent electrical properties. And the first electrode 10a is arranged on the ITO material layer 31 with a relatively low indium content in the transparent conductive composite film layer 3 to achieve ohmic contact. The ITO material with a relatively low indium content has relatively strong adhesion ability, which can improve the contact force between the transparent conductive composite film layer 3 and the first electrode 10a, that is, reduce the hindrance to the current transmission process, improve the short-circuit current (Isc), and also improve the reliability of the solar heterojunction battery and reduce the production cost.

[0034] In one embodiment, the transparent conductive composite film layer 3 further includes a penetration layer 33. The penetration layer 33 is arranged between the VTTO material layer 32 and the ITO material layer 31, and the penetration layer 33 is formed by the mutual penetration of the VTTO material and the ITO material.

[0035] Compared with the multi-layer transparent conductive thin films in the traditional stacked structure, the penetration layer 33 provided in this application can form a transition region between the VTTO material layer 32 and the ITO material layer 31 by virtue of the atomic permeability of the VTTO target and the ITO target, so that there is no obvious boundary line between the VTTO material layer 32 and the ITO material layer 31, thereby reducing the resistance during the carrier transmission process, further improving the carrier mobility and conductivity, so as to meet the higher power generation requirements for the front side of the solar heterojunction battery.

[0036] It should be noted that the above-mentioned penetration layer 33 can be prepared by simultaneously sputtering the VTTO target and the ITO target using the existing magnetron sputtering process. This process method belongs to the existing known technology and will not be elaborated here.

[0037] In one embodiment, the solar heterojunction battery further includes a first transparent conductive film layer 4; the first transparent conductive film layer 4 is stacked between the first doped crystalline silicon layer 2 and the transparent conductive composite film layer 3, and the first transparent conductive film layer 4 is made of the same material as the VTTO material layer 32. Thus, the first transparent conductive film layer 4 in the stacked structure can be used to compensate for the thickness of the VTTO material layer 32 in the transparent conductive composite film layer 3, and on the premise of meeting the power generation of the front side of the battery, the thickness of the VTTO material layer 32 in the transparent conductive composite film layer 3 can be reduced as much as possible, thereby reducing the peeling risk of the transparent conductive composite film layer 3.

[0038] It should be noted that the "same material" mentioned in this application means that the material components and the content of each component are the same.

[0039] In one embodiment, the solar heterojunction battery further includes a second transparent conductive film layer 5; the second transparent conductive film layer 5 is stacked between the first transparent conductive film layer 4 and the transparent conductive composite film layer 3; the second transparent conductive film layer 5 includes a fluorine-doped tin oxide layer. Thus, the purpose of indium-free can be achieved and the cost can be reduced.

[0040] It should be noted that the mass ratio of tin dioxide to fluorine in the fluorine-doped tin oxide layer is (80 - 85):(15 - 20).

[0041] In one embodiment, the first electrode 10a is a composite metal electrode, including a first metal and a second metal; the materials of the first metal and the second metal are different, and both the first metal and the second metal are in contact with the ITO material layer 31. Thus, the matching with the transparent conductive composite film layer 3 can be improved. Exemplarily, the first metal can be copper and the second metal can be silver, but it is not limited thereto.

[0042] In one embodiment, the solar heterojunction cell further includes a second doped crystalline silicon layer 6, a third transparent conductive film layer 7, and a fourth transparent conductive film layer 8 that are sequentially stacked on the back surface of the silicon substrate 1; the third transparent conductive film layer 7 is made of the same material as the VTTO material layer 32, and the fourth transparent conductive film layer 8 is made of the same material as the ITO material layer 31. Thus, the third transparent conductive film layer 7 with a higher indium content cooperates with the second doped crystalline silicon layer 6, which can improve the carrier mobility and conductivity, thereby increasing the short-circuit current (Isc) and fill factor (FF), having excellent electrical properties, and reducing the cost.

[0043] It should be noted that since the back surface of the solar heterojunction cell does not need to meet the requirement of too high power generation compared with the front surface, in some embodiments, there may be an obvious dividing line between the third transparent conductive film layer 7 and the fourth transparent conductive film layer 8, and there is no need to provide the penetration layer 33.

[0044] In one embodiment, the solar heterojunction cell further includes a transparent conductive sandwich film layer 9; the transparent conductive sandwich film layer 9 is stacked between the third transparent conductive film layer 7 and the fourth transparent conductive film layer 8; the transparent conductive sandwich film layer 9 includes a first non-indium material layer 91, a second non-indium material layer 92, and a sandwich material layer 93; the materials of the first non-indium material layer 91 and the second non-indium material layer 92 are different; the sandwich material layer 93 is stacked between the first non-indium material layer 91 and the second non-indium material layer 92, and the sandwich material layer 93 includes a fluorine-doped tin oxide layer.

[0045] By providing a transparent conductive sandwich film layer 9 made of non-indium materials between the third transparent conductive film layer 7 and the fourth transparent conductive film layer 8, the purpose of indium-free can be achieved, and the production cost can be reduced. However, during the continuous production process between the first non-indium material layer 91 and the second non-indium material layer 92, the atomic penetration phenomenon between the two will continuously weaken, so the independence of the two becomes stronger, reducing the carrier mobility and unable to meet the actual production requirements. Therefore, by adding a fluorine-doped tin oxide layer as the sandwich material layer 93 between the first non-indium material layer 91 and the second non-indium material layer 92, a large number of high-valent tin ions can be obtained to have higher energy, enhancing the ability to capture carriers, ensuring that carriers can pass through the transparent conductive sandwich film layer 9 with lower loss, increasing the power generation, and realizing the indium-free development of the transparent conductive thin film.

[0046] In addition, since the material of the sandwich material layer 93 is the same as that of the second transparent conductive film layer 5 on the front surface of the cell, the purpose of homogenization can be achieved, that is, during the actual coating process, only the same process parameters are required to prepare the second transparent conductive film layer 5 on the front surface of the cell and the sandwich material layer 93 on the back surface of the cell, reducing the complexity of the coating process.

[0047] In one embodiment, the first non-indium material layer 91 includes an FTO material layer, and the tin content of the FTO material layer is less than that of the fluorine-doped tin oxide layer; the second non-indium material layer 92 includes an AZO material layer. Thus, the FTO material layer and the fluorine-doped tin oxide layer can cooperate better to reduce the carrier transmission resistance; and since the zinc oxide crystal structure in the AZO material layer is stable and has the functions of medium and low resistance and low work function, when used in combination with the FTO material layer, the cost can be reduced.

[0048] It should be noted that the mass ratio of tin dioxide to fluorine in the FTO material is less than 80:20. The AZO material refers to aluminum-doped zinc oxide (ZnO:Al).

[0049] In one embodiment, the second doped crystalline silicon layer 6 includes a P-type doped crystalline silicon layer. In one embodiment, the first doped crystalline silicon layer 2 includes an N-type doped crystalline silicon layer.

[0050] It should be noted that the silicon substrate 1 in the solar heterojunction cell provided in this application can be an N-type silicon wafer or a P-type silicon wafer. The N-type doped crystalline silicon layer can be an N-type doped amorphous silicon layer formed by doping boron atoms in a partial area of the first intrinsic amorphous silicon layer, or an N-type doped microcrystalline silicon layer formed by doping boron atoms in a partial area of the first intrinsic microcrystalline silicon layer. Among them, the first intrinsic amorphous silicon layer / first intrinsic microcrystalline silicon layer can be formed on the front side of the silicon substrate 1. The P-type doped crystalline silicon layer can also be a P-type doped amorphous silicon layer formed by doping phosphorus atoms in a partial area of the second intrinsic amorphous silicon layer, or a P-type doped microcrystalline silicon layer formed by doping phosphorus atoms in a partial area of the second intrinsic microcrystalline silicon layer. Among them, the second intrinsic amorphous silicon layer / second intrinsic microcrystalline silicon layer can be formed on the back side of the silicon substrate 1.

[0051] When the FTO material layer and the AZO material layer are disposed on the N-type doped crystalline silicon layer on the front side of the battery, due to the high sunlight absorption rate on the front side of the battery, a large number of boron-doped ions in the N-type doped crystalline silicon layer and ions in the electrode, such as copper ions, will form boron-copper compounds, which will hinder the transport of carriers, reduce the conductivity and fill factor (FF). Moreover, the conductivity of the FTO material layer and the AZO material layer is not as strong as that of the VTTO material and the ITO material, and there is no obvious compensation for the fill factor (FF) on the front side of the battery. However, due to the low sunlight absorption rate on the back side of the battery, a small amount of phosphorus-doped ions in the P-type doped crystalline silicon layer and metal ions in the electrode, such as copper ions, will form phosphorus-copper compounds, that is, the number of compounds generated is less than that on the front side of the battery. Therefore, disposing the FTO material layer and the AZO material layer on the back side of the battery can limit the transition of phosphorus-doped ions or metal ions, and can significantly compensate for the fill factor (FF) compared with the front side of the battery, and can also meet the power requirements on the back side of the battery.

[0052] In one embodiment, the solar heterojunction battery further includes a second electrode 10b connected to the fourth transparent conductive film layer 8. Thus, the ITO material with less indium content has relatively strong adhesion ability, which can improve the contact force between the fourth transparent conductive film layer 8 and the second electrode 10b, and improve the short-circuit current (Isc) and the reliability of the solar heterojunction battery.

[0053] On the other hand, the present application also provides a coating device, including a plurality of physical vapor deposition chambers for depositing a plurality of transparent conductive film layers on any one of the above-mentioned solar heterojunction batteries.

[0054] Please refer to Figure 2 , in one embodiment, the coating device includes a first physical vapor deposition chamber 20, a second physical vapor deposition chamber 21 and a third physical vapor deposition chamber 22; the first physical vapor deposition chamber 20 is used for depositing a first transparent conductive film layer 4; the second physical vapor deposition chamber 21 is communicated with the outlet of the first physical vapor deposition chamber 20 and is used for depositing a second transparent conductive film layer 5; the third physical vapor deposition chamber 22 is communicated with the outlet of the second physical vapor deposition chamber 21 and is used for depositing a transparent conductive composite film layer 3.

[0055] In one embodiment, the coating device further includes an isolation chamber 23, a fourth physical vapor deposition chamber 24, a fifth physical vapor deposition chamber 25, and a sixth physical vapor deposition chamber 26; the isolation chamber 23 is communicated with the outlet of the third physical vapor deposition chamber 22; the fourth physical vapor deposition chamber 24 is communicated with the outlet of the isolation chamber 23 and is used for depositing a third transparent conductive film layer 7; the fifth physical vapor deposition chamber 25 is communicated with the outlet of the fourth physical vapor deposition chamber 24 and is used for depositing a transparent conductive sandwich film layer 9; the sixth physical vapor deposition chamber 26 is communicated with the outlet of the fifth physical vapor deposition chamber 25 and is used for depositing a fourth transparent conductive film layer 8.

[0056] In one embodiment, the fifth physical vapor deposition chamber 25 includes a first sub-deposition chamber 251, a second sub-deposition chamber 252, a third sub-deposition chamber 253, and a fourth sub-deposition chamber 254 that are sequentially communicated. Among them, the first sub-deposition chamber 251 is used for depositing FTO material, the second sub-deposition chamber 252 is used for co-sputtering FTO material and fluorine-doped tin oxide material, the third sub-deposition chamber 253 is used for co-sputtering fluorine-doped tin oxide material and AZO material, and the fourth sub-deposition chamber 254 is used for depositing AZO material. Thus, the overall plating of the transparent conductive sandwich film layer 9 can be realized.

[0057] In one embodiment, a residual gas analysis and monitoring component (RGA) F is provided in the first physical vapor deposition chamber 20 for monitoring and analyzing gases such as water vapor in the first physical vapor deposition chamber 20, so as to better control the preparation effect of the second transparent conductive film intermediate and the first transparent conductive layer. In another embodiment, a plurality of mechanical pumps A, roots pumps B, molecular pumps C, cold traps D, and heating modules E are further provided on the coating device. Thus, it is convenient to provide a variety of materials and a more suitable temperature environment in the coating device.

[0058] In one embodiment, the coating device further includes a front transition chamber 27, and the front transition device includes a first transition chamber 271, a first heating chamber 272, and a second heating chamber 273 that are sequentially arranged. Thus, it is convenient to raise the solar heterojunction battery to a higher working temperature before coating, which is beneficial to better subsequent coating. In another embodiment, the coating device further includes a rear transition chamber 28, and the rear transition device includes a first cooling chamber 281, a second cooling chamber 282, and a second transition chamber 283 that are sequentially arranged. Thus, it is convenient to provide a cooling working environment for the solar heterojunction battery after coating and improve the coating effect.

[0059] The above embodiments can be combined with each other on the premise that the technical means recorded in each are not in conflict. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this application shall be included within the scope of protection of this application.

Claims

1. A solar heterojunction cell, characterized in that: include: A silicon substrate (1), a first doped crystalline silicon layer (2), a transparent conductive composite film layer (3) and a first electrode (10a); The first doped crystalline silicon layer (2) and the transparent conductive composite film layer (3) are sequentially stacked on the front surface of the silicon substrate (1); The transparent conductive composite film layer (3) comprises a VTTO material layer (32) and an ITO material layer (31); the VTTO material layer (32) is arranged toward the silicon substrate (1); the ITO material layer (31) is arranged with its back facing the silicon substrate (1); the VTTO material layer (32) and the ITO material layer (31) have the same material composition, and the indium content of the VTTO material layer (32) is greater than the indium content of the ITO material layer (31); The first electrode (10a) is arranged on the ITO material layer (31).

2. The solar heterojunction cell according to claim 1, characterized in that: The transparent conductive composite film layer (3) further comprises a permeation layer (33); The penetration layer (33) is arranged between the VTTO material layer (32) and the ITO material layer (31), and the penetration layer (33) is formed by mutual penetration of the VTTO material and the ITO material.

3. The solar heterojunction cell according to claim 1, characterized in that: The solar heterojunction cell further comprises a first transparent conductive film layer (4); The first transparent conductive film layer (4) is stacked between the first doped crystalline silicon layer (2) and the transparent conductive composite film layer (3), and the first transparent conductive film layer (4) and the VTTO material layer (32) are made of the same material.

4. The solar heterojunction cell according to claim 3, characterized in that: The solar heterojunction cell further comprises a second transparent conductive film layer (5); The second transparent conductive film layer (5) is stacked between the first transparent conductive film layer (4) and the transparent conductive composite film layer (3); the second transparent conductive film layer (5) comprises a fluorine-doped tin oxide layer.

5. The solar heterojunction cell according to claim 1, characterized in that: The first electrode (10a) is a composite metal electrode, comprising a first metal and a second metal; the first metal and the second metal are made of different materials, and both the first metal and the second metal are in contact with the ITO material layer (31).

6. The solar heterojunction cell according to any one of claims 1 to 5, characterized in that: The solar heterojunction cell further comprises a second doped crystalline silicon layer (6), a third transparent conductive film layer (7) and a fourth transparent conductive film layer (8) which are sequentially stacked on the back side of the silicon substrate (1); The third transparent conductive film layer (7) is made of the same material as the VTTO material layer (32), and the fourth transparent conductive film layer (8) is made of the same material as the ITO material layer (31).

7. The solar heterojunction cell according to claim 6, characterized in that: The solar heterojunction cell further comprises a transparent conductive sandwich film layer (9); The transparent conductive sandwich film layer (9) is stacked between the third transparent conductive film layer (7) and the fourth transparent conductive film layer (8); the transparent conductive sandwich film layer (9) comprises a first non-indium material layer (91), a second non-indium material layer (92) and a sandwich material layer (93); The first non-indium material layer (91) and the second non-indium material layer (92) are made of different materials; the sandwich material layer (93) is stacked between the first non-indium material layer (91) and the second non-indium material layer (92), and the sandwich material layer (93) comprises a fluorine-doped tin oxide layer.

8. The solar heterojunction cell according to claim 7, characterized in that: The first non-indium material layer (91) comprises a FTO material layer, the tin content of the FTO material layer is less than the tin content of the fluorine-doped tin oxide layer; the second non-indium material layer (92) comprises an AZO material layer.

9. The solar heterojunction cell according to claim 8, characterized in that: The second doped crystalline silicon layer (6) comprises a P-type doped crystalline silicon layer.

10. The solar heterojunction cell according to claim 6, characterized in that: The solar heterojunction cell further comprises a second electrode (10b) connected to the fourth transparent conductive film layer (8).

Images