A crystalline silicon perovskite tandem solar cell and a method of manufacture

Abstract

The application discloses a crystalline silicon perovskite laminated solar cell and a preparation method. The cell comprises, from bottom to top, a crystalline silicon solar cell, an intermediate transparent conductive layer, a metal oxide layer and a perovskite solar cell which are sequentially laminated, wherein the intermediate transparent conductive layer covers part of the area of the crystalline silicon solar cell; each edge of the intermediate transparent conductive layer is recessed from the edge of the adjacent crystalline silicon solar cell by a certain distance; and the metal oxide layer covers the intermediate transparent conductive layer and the area of the crystalline silicon solar cell which is not covered by the intermediate transparent conductive layer. The cell can reduce the risk of electric leakage and short circuit of the crystalline silicon perovskite laminated solar cell.

Description

[0001] This invention claims priority to Chinese Patent Application No. 202111232844.5, filed on October 22, 2021, entitled “A Crystalline Silicon Perovskite Tandem Solar Cell and a Method for its Fabrication”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to a crystalline silicon perovskite tandem solar cell and its fabrication method. Background Technology

[0003] Currently, crystalline silicon perovskite tandem solar cells offer a promising technological path for further improving solar cell efficiency. The basic structure of a crystalline silicon perovskite tandem solar cell involves placing a conductive layer between crystalline silicon and perovskite solar cells, thus achieving the superposition of these two solar cells. However, existing crystalline silicon perovskite tandem solar cells are prone to leakage and have a high risk of short circuits. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a crystalline silicon perovskite tandem solar cell and a method for its preparation, which can reduce the leakage and short circuit risks of crystalline silicon perovskite tandem solar cells.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a crystalline silicon perovskite tandem solar cell, comprising: a crystalline silicon solar cell, an intermediate transparent conductive layer, a metal oxide layer, and a perovskite solar cell stacked sequentially from bottom to top, wherein...

[0007] The intermediate transparent conductive layer covers a portion of the crystalline silicon solar cell;

[0008] Each edge of the intermediate transparent conductive layer is recessed by a set distance relative to the edge of its adjacent crystalline silicon solar cell;

[0009] The metal oxide layer covers the intermediate transparent conductive layer and the areas of the crystalline silicon solar cell not covered by the intermediate transparent conductive layer.

[0010] Secondly, the present invention provides a method for preparing a crystalline silicon perovskite tandem solar cell, comprising:

[0011] Step 1: Fabricating a partial structure of a crystalline silicon solar cell based on a silicon wafer;

[0012] Step 2: An intermediate transparent conductive layer is prepared on the n-type amorphous silicon included in a portion of the structure of the crystalline silicon solar cell, wherein each edge of the intermediate transparent conductive layer is recessed by a set distance relative to the edge of its adjacent crystalline silicon solar cell.

[0013] Step 3: Prepare a metal oxide layer on the intermediate transparent conductive layer and on the areas of the crystalline silicon solar cell not covered by the intermediate transparent conductive layer;

[0014] Step 4: Fabricate a perovskite solar cell on the metal oxide layer.

[0015] The first aspect of the invention described above has the following advantages or beneficial effects: The crystalline silicon perovskite tandem solar cell provided in this embodiment defines the effective area of ​​the crystalline silicon perovskite tandem solar cell because each edge of the intermediate transparent conductive layer disposed between the crystalline silicon solar cell and the perovskite solar cell is recessed by a set distance relative to the edge of its adjacent crystalline silicon solar cell. Therefore, even if the edges of the crystalline silicon perovskite tandem solar cell are cut, the integrity of the intermediate transparent conductive layer can still be guaranteed, that is, the integrity of the effective area of ​​the crystalline silicon solar cell and the perovskite solar cell can be guaranteed, thereby reducing the leakage and short-circuit risks of the crystalline silicon perovskite tandem solar cell.

[0016] In addition, by setting a metal oxide layer that covers the intermediate transparent conductive layer and the areas of the crystalline silicon solar cell not covered by the intermediate transparent conductive layer, this oxide layer serves as both a hole transport layer for perovskite solar cells to transport electrons and a bonding layer between the crystalline silicon solar cell and the perovskite solar cell, which can significantly increase the sheet resistance between the crystalline silicon solar cell and the perovskite solar cell. That is, the sheet resistance of this bonding layer is significantly higher than that of the intermediate transparent conductive layer alone, thereby further reducing the leakage and short-circuit risks of crystalline silicon perovskite tandem solar cells.

[0017] In addition, the reduction of leakage and short-circuit risks in perovskite solar cells can effectively improve the performance and yield of crystalline silicon perovskite tandem solar cells, such as high open-circuit voltage and cell conversion efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the frame structure of a crystalline silicon perovskite tandem solar cell according to an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of a textured crystalline silicon perovskite tandem solar cell frame structure according to an embodiment of the present invention.

[0020] Figure 3This is a cross-sectional schematic diagram of a crystalline silicon perovskite tandem solar cell according to an embodiment of the present invention;

[0021] Figure 4 This is a schematic cross-sectional view of a crystalline silicon perovskite tandem solar cell according to another embodiment of the present invention;

[0022] Figure 5 This is a cross-sectional schematic diagram of a crystalline silicon perovskite tandem solar cell according to another embodiment of the present invention;

[0023] Figure 6 This is a schematic cross-sectional view of a crystalline silicon perovskite tandem solar cell according to another embodiment of the present invention;

[0024] Figure 7 This is a top view showing the relative relationship between the intermediate transparent conductive layer and the crystalline silicon solar cell according to an embodiment of the present invention;

[0025] Figure 8 This is a schematic diagram of the main process of fabricating a crystalline silicon perovskite tandem solar cell according to an embodiment of the present invention.

[0026] The attached figures are labeled as follows:

[0027] 10-Crystal Silicon Solar Cells

[0028] 11-Backside conductive gate line; 12-Backside transparent conductive layer; 13-P-type amorphous silicon layer

[0029] 14-First intrinsic amorphous silicon layer; 15-Silicon wafer; 16-Second intrinsic amorphous silicon layer

[0030] 17-n type amorphous silicon layer

[0031] 20 - Intermediate transparent conductive layer;

[0032] 30-Metal oxide layer;

[0033] 40-Perovskite Solar Cells

[0034] 41-Absorption layer; 42-Electron transport layer; 43-Front-side transparent conductive layer

[0035] 44-Front-side conductive grid lines

[0036] 50-passivation layer Detailed Implementation

[0037] Through research on existing silicon-perovskite tandem solar cells, the inventors discovered that the main reason why existing silicon-perovskite tandem solar cells are prone to leakage and have a high risk of short circuits is that the conductive layer set between the crystalline silicon solar cell and the perovskite solar cell is generally set according to the size of the silicon wafer in the crystalline silicon solar cell. Therefore, during the process of removing the irregular or burr edges of the crystalline silicon-perovskite tandem solar cell by cutting, the conductive layer set between the crystalline silicon solar cell and the perovskite solar cell is easily damaged, making the perovskite solar cell prone to leakage and causing short circuits.

[0038] To address the aforementioned problems, embodiments of the present invention provide a crystalline silicon perovskite tandem solar cell. For example... Figures 1 to 6 The diagram shows a partial cross-sectional structure of a crystalline silicon perovskite tandem solar cell. It is worth noting that the cutting direction of this partial cross-sectional structure is perpendicular to the extension direction of the conductive grid lines of the crystalline silicon perovskite tandem solar cell.

[0039] like Figures 1 to 6 As shown, the crystalline silicon perovskite tandem solar cell may include: a crystalline silicon solar cell 10, an intermediate transparent conductive layer 20, a metal oxide layer 30, and a perovskite solar cell 40 stacked sequentially from bottom to top, wherein the intermediate transparent conductive layer 20 covers a portion of the crystalline silicon solar cell 10. The metal oxide layer 30 covers the intermediate transparent conductive layer 20 and areas of the crystalline silicon solar cell 10 not covered by the intermediate transparent conductive layer 20.

[0040] Specifically, regarding the portion of the crystalline silicon solar cell 10 covered by the intermediate transparent conductive layer 20, such as... Figure 7 The diagram shows a top view of the relative position between the intermediate transparent conductive layer 20 and the crystalline silicon solar cell 10. Each edge a of the intermediate transparent conductive layer 20 is recessed by a set distance L relative to the edge b of its adjacent crystalline silicon solar cell 10. This recess means that each edge a of the intermediate transparent conductive layer 20 moves towards the center of the intermediate transparent conductive layer 20 or the direction of its central axis, so that the projection of the main surface of the intermediate transparent conductive layer 20 is included within the projection of the main surface of the crystalline silicon solar cell 10, and the projection of the main surface of the intermediate transparent conductive layer 20 is smaller than the projection of the main surface of the crystalline silicon solar cell 10.

[0041] Preferably, the aforementioned set distance L is generally greater than or equal to 4 mm. For example, the set distance L can be 4 mm, 6 mm, 8 mm, 10 mm, etc. It is worth noting that this set distance L generally needs to ensure that the function of the intermediate transparent conductive layer 20 is not affected. That is, while ensuring that the set distance L is greater than or equal to 4 mm, the final value of the set distance L needs to be determined based on the size of the crystalline silicon perovskite tandem solar cell and the required size of the intermediate transparent conductive layer 20. For example, if the length and width of the crystalline silicon perovskite tandem solar cell are both α mm, and the minimum length and width of the required intermediate transparent conductive layer 20 are both β mm, then... The distance can then be set as follows: Any value in the set. For example, The distance can be set to 4mm, 5mm, 6mm, 7mm, 8mm, etc. Generally, the intermediate transparent conductive layer 20 defines the effective area of ​​the crystalline silicon perovskite tandem solar cell. Since this effective area is relatively small compared to the area of ​​the crystalline silicon solar cell, the area affected by edge damage of the silicon wafer of the crystalline silicon solar cell will not affect the effective area of ​​the crystalline silicon perovskite tandem solar cell, thus eliminating the negative impact of edge damage on the performance of the crystalline silicon perovskite tandem solar cell.

[0042] Furthermore, the aforementioned metal oxide layer covers the intermediate transparent conductive layer 20 and the areas of the crystalline silicon solar cell 10 not covered by the intermediate transparent conductive layer 20. Therefore, compared to the crystalline silicon perovskite tandem solar cell, this metal oxide layer has a complete crystalline structure. This metal oxide layer with a complete crystalline structure can have a higher resistivity. Thus, the combination of the metal oxide layer and the intermediate transparent conductive layer can effectively increase the resistivity between the crystalline silicon solar cell 10 and the perovskite solar cell 40. Nickel oxide has a high resistivity, thereby reducing the risk of leakage and short circuit in the crystalline silicon perovskite tandem solar cell.

[0043] It is worth noting that the crystalline silicon solar cell 10 involved in the various embodiments of the present invention can be a heterojunction structure, or a PERC, Top-con, or other structures.

[0044] In summary, the crystalline silicon perovskite tandem solar cell provided in this embodiment of the invention defines the effective area of ​​the crystalline silicon perovskite tandem solar cell because each edge of the intermediate transparent conductive layer disposed between the crystalline silicon solar cell and the perovskite solar cell is recessed by a set distance relative to the edge of its adjacent crystalline silicon solar cell. Therefore, even if the edges of the crystalline silicon perovskite tandem solar cell are cut, the integrity of the intermediate transparent conductive layer can still be guaranteed, that is, the integrity of the effective areas of the crystalline silicon solar cell and the perovskite solar cell can be guaranteed, thereby reducing the leakage and short-circuit risks of the crystalline silicon perovskite tandem solar cell.

[0045] In addition, by setting a metal oxide layer that covers the intermediate transparent conductive layer and the areas of the crystalline silicon solar cell not covered by the intermediate transparent conductive layer, this oxide layer serves both as a hole transport layer for the perovskite solar cell to transport holes and as a bonding layer between the crystalline silicon solar cell and the perovskite solar cell, which can significantly improve the sheet resistance between the crystalline silicon solar cell and the perovskite solar cell. That is, the sheet resistance of this bonding layer is significantly higher than that of the intermediate transparent conductive layer alone, thereby further reducing the leakage and short circuit risks of the crystalline silicon perovskite tandem solar cell.

[0046] In addition, the reduction of leakage and short-circuit risks in crystalline silicon perovskite tandem solar cells can effectively improve the high open-circuit voltage, cell conversion efficiency, and yield of crystalline silicon perovskite tandem solar cells.

[0047] In a preferred embodiment, the above Figures 1 to 6 The metal oxide layer 30 shown can be a metal-doped nickel oxide layer. On the one hand, because nickel oxide (NiO) x O is easily filled in the crystal lattice 2- And Ni 2+ The vacancy is that of a p-type semiconductor material with high chemical stability and hole mobility, with a hole mobility reaching up to 47.05 cm⁻¹. 2 / (V·s), while NiO x The work function can be adjusted by changing the gap O. 2- or Ni 2+ By controlling the concentration within the range of 4.5–5.6 eV, a well-matched energy level structure with the perovskite material in perovskite solar cells can be achieved. Furthermore, NiO… x The high conduction band energy level (-1.8 eV) can also effectively block electron leakage from the perovskite material to the positive electrode. This illustrates that NiO is crucial in inverted pin perovskite solar cell devices and crystalline silicon perovskite tandem solar cells. x Nickel oxide can serve as an ideal hole transport layer material. On the other hand, nickel oxide with a complete crystal structure has high resistivity; even non-stoichiometric P-type films with introduced nickel vacancies and oxygen interstices still exhibit high resistivity. Research has shown that introducing metal doping into nickel oxide can not only reduce its resistivity but also improve the transmittance of nickel oxide films in the near-infrared region. This further enhances the open-circuit voltage and conversion efficiency of crystalline silicon perovskite tandem solar cells. The metal doped in this metal-doped nickel oxide layer can include any one or more of copper, cobalt, manganese, lanthanum, yttrium, magnesium, lithium, zinc, indium, and tin. The choice of doping metal can be made according to actual needs; for example, copper can be chosen to reduce costs, while zinc, indium, or tin can be selected to obtain better performance.

[0048] In this embodiment of the invention, the thickness of the aforementioned metal oxide layer is generally less than or equal to 100 nm. For example, 100 nm, 95 nm, 90 nm, 80 nm, 70 nm, 50 nm, 30 nm, 20 nm, etc., to avoid excessively thick metal oxide layers that would lead to excessively high resistivity and affect light transmittance. Therefore, by controlling the thickness of the metal oxide layer to 100 nm or less, resistivity, light transmittance, etc., can be controlled to ensure the performance of the crystalline silicon perovskite tandem solar cell.

[0049] Furthermore, the thickness of this metal oxide layer is generally greater than or equal to 20 nm. This is because, for metal-doped nickel oxide layers, a target material can be prepared by thoroughly grinding or co-precipitating a certain proportion of nickel oxide and the corresponding doped metal oxide, followed by hot pressing and sintering. The metal-doped nickel oxide layer can then be prepared using magnetron sputtering or electron beam evaporation deposition. Since existing magnetron sputtering or electron beam evaporation deposition methods struggle to guarantee a metal oxide layer coverage below 20 nm, a thickness greater than or equal to 20 nm is generally required to ensure the integrity of the metal-doped nickel oxide layer. However, with advancements in magnetron sputtering or electron beam evaporation deposition technology, the integrity or coverage of the metal oxide layer can be satisfied even when it is a monolayer. Therefore, the thickness of the metal oxide layer can be reduced to below 20 nm, or even to a single layer.

[0050] The thickness of the intermediate transparent conductive layer 20 is less than or equal to 50 nm, for example, 50 nm, 45 nm, 40 nm, 35 nm, 30 nm, 25 nm, 20 nm, etc. Since the intermediate transparent conductive layer 20 has high lateral conductivity, its thickness is generally reduced to increase its sheet resistance and thus reduce its lateral conductivity. Simultaneously, a thicker intermediate transparent conductive layer 20 increases parasitic absorption of incident light. Therefore, considering both electrical and optical requirements, the thickness of the intermediate transparent conductive layer 20 needs to be reduced. For the crystalline silicon perovskite tandem solar cell structure provided in this embodiment, controlling the thickness of the intermediate transparent conductive layer 20 to be less than or equal to 50 nm effectively improves cell performance and yield.

[0051] Furthermore, the lower limit of the thickness of the intermediate transparent conductive layer 20 is generally to ensure that the projection of the intermediate transparent conductive layer can cover more than 80% of the main surface of the perovskite solar cell or the main surface of the crystalline silicon solar cell (an excessively thin intermediate transparent conductive layer cannot guarantee coverage), so as to ensure that the cell performance and yield do not decrease. However, in order to ensure the coverage of the intermediate transparent conductive layer 20, the intermediate transparent conductive layer 20 cannot be infinitely thin. For example, existing sputtering processes are difficult to guarantee the surface coverage of the intermediate transparent conductive layer 20 below 20 nm. Therefore, when using existing sputtering processes to prepare the intermediate transparent conductive layer, the thickness of the intermediate transparent conductive layer must be greater than or equal to 20 nm. If a more advanced technology can be used to ensure that the coverage of the intermediate transparent conductive layer is not less than 80% when it is a monolayer, then the thickness of the intermediate transparent conductive layer can also be the thickness of a monolayer, that is, to further reduce the thickness of the intermediate transparent conductive layer.

[0052] The intermediate transparent conductive layer 20 may include any one or more combinations of indium tin oxide, indium tungsten oxide, indium zinc oxide, aluminum-doped zinc oxide, boron-doped zinc oxide, indium gallium zinc oxide, and magnesium-doped zinc oxide. Specifically, the intermediate transparent conductive layer 20 may be a single-layer structure or a stacked structure formed by any one or more of indium tin oxide, indium tungsten oxide, indium zinc oxide, aluminum-doped zinc oxide, boron-doped zinc oxide, indium gallium zinc oxide, and magnesium-doped zinc oxide. For example, each layer in the single-layer structure or the stacked structure may include any one or more of indium tin oxide, indium tungsten oxide, indium zinc oxide, aluminum-doped zinc oxide, boron-doped zinc oxide, indium gallium zinc oxide, and magnesium-doped zinc oxide. In a preferred embodiment, the intermediate transparent conductive layer 20 may include indium tin oxide and / or indium tungsten oxide. It is worth noting that the intermediate transparent conductive layer 20 may be obtained by solution spin coating, spraying, sol-gel method, magnetron sputtering, vacuum evaporation deposition, chemical vapor deposition, etc.

[0053] Generally, most perovskite materials are adjacent to metal oxide layers such as NiO. x The chemical interactions between them are very weak, which limits the use of metal oxide layers such as NiO. x The power conversion efficiency of crystalline silicon perovskite tandem solar cells or inverted pin perovskite solar cells, which serve as hole transport layers, is affected. Furthermore, the metal oxide layer itself contains numerous defects, which can form carrier recombination sites upon contact with other interfaces, such as the absorber layer of a perovskite solar cell. This affects carrier transport efficiency and consequently the overall performance of the crystalline silicon perovskite tandem solar cell. To address these problems with the metal oxide layer, in embodiments of the present invention, such as... Figure 4 and Figure 6 As shown, the crystalline silicon perovskite tandem solar cell may further include a passivation layer 50 disposed between the perovskite solar cell 40 and the metal oxide layer 30.

[0054] The passivation layer 50 can be a monolayer or stacked structure formed from any one or more of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), aniline iodide (PMAI), hexyltrimethylammonium bromide (HTAB), polymethyl methacrylate (PMMA), and 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone (F4TCNQ). It is worth noting that the stacked structure is formed by stacking multiple monolayer structures, and each monolayer structure or stacked structure can include any one compound or a combination of multiple compounds selected from poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), aniline iodide (PMAI), hexyltrimethylammonium bromide (HTAB), polymethyl methacrylate (PMMA), and 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone (F4TCNQ).

[0055] The passivation layer provided in this embodiment of the invention can effectively improve the interfacial contact between the passivation layer and the perovskite solar cell, improve the quality of the perovskite solar cell, and enhance the connection between the doped nickel oxide layer and the perovskite solar cell, thereby increasing the current of the crystalline silicon perovskite tandem solar cell. Furthermore, by inserting a passivation layer between the doped nickel oxide layer and the perovskite solar cell, the number of interface defect states can be reduced, nonradiative recombination of carriers can be suppressed, and ultimately, the open-circuit voltage V can be reduced. OC The loss of such materials and materials has great potential for promoting the commercial application of crystalline silicon perovskite tandem solar cells.

[0056] Furthermore, such as Figures 3 to 6 As shown, the perovskite solar cell 40 included in the crystalline silicon perovskite tandem solar cell may include: an absorber layer 41, an electron transport layer 42, a front transparent conductive layer 43, and a front conductive grid line 44 stacked sequentially from bottom to top, wherein the front transparent conductive layer 43 covers a portion of the electron transport layer 42; the indentation distance of each edge of the front transparent conductive layer 43 relative to the edge of its adjacent electron transport layer 42 is greater than or equal to 4 mm.

[0057] It is worth noting that the projection of the main surface of the front transparent conductive layer 43 completely coincides with the projection of the main surface of the middle transparent conductive layer 20. That is, the size of the front transparent conductive layer 43 is basically the same as the size of the middle transparent conductive layer 20, and the position of the front transparent conductive layer 43 on the electron transport layer is basically the same as the position of the middle transparent conductive layer 20 on the crystalline silicon solar cell 10.

[0058] The area of the front transparent conductive layer 43 also determines the effective area of the crystalline silicon perovskite tandem solar cell. Therefore, by designing the relationship between the front transparent conductive layer 43 and the intermediate transparent conductive layer 20, the front transparent conductive layer 43 and the intermediate transparent conductive layer 20 can be utilized more effectively, avoiding waste of partial areas of the front transparent conductive layer 43 or the intermediate transparent conductive layer 20 due to the inconsistency between the front transparent conductive layer 43 and the intermediate transparent conductive layer 20.

[0059] Among them, the absorption layer 41 may include: MAPbI3, FAPbI3, Cs x (FA y MA 1-y ) 1-x Pb(I z Br 1-z )3, where 0 < x ≤ 0.2, 0.5 < y ≤ 1, 0.75 ≤ z < 1. In addition, there may also be elements such as Rb, Li, Na, K, Sn, Cl, Br, etc. in the absorption layer 41. Doping with different elements can change semiconductor properties such as the bandgap width and mobility of the material to a certain extent, affecting the performance of the device, and also affecting the lifespan and light and heat stability of the material. The absorption layer can be designed with different element doping according to actual requirements.

[0060] In the embodiment of the present invention, the thickness of the above-mentioned front transparent conductive layer 43 is within the range of 50 nm to 200 nm. For example, the thickness of the front transparent conductive layer 43 can be 50 nm, 60 nm, 65 nm, 70 nm, 80 nm, 90 nm, 100 nm, 120 nm, 140 nm, 150 nm, 160 nm, 180 nm, 200 nm, etc. By controlling the thickness of the front transparent conductive layer 43 within the range of 50 nm to 200 nm, the leakage risk can be effectively reduced while improving the performance of the crystalline silicon perovskite tandem solar cell.

[0061] In the embodiment of the present invention, as Figures 3 to 6 shown, the crystalline silicon solar cell 10 in the crystalline silicon perovskite tandem solar cell may include: a back conductive grid line 11, a back transparent conductive layer 12, a p-type amorphous silicon layer 13, a first intrinsic amorphous silicon layer 14, a silicon wafer 15, a second intrinsic amorphous silicon layer 16, and an n-type amorphous silicon layer 17 stacked in sequence from bottom to top. Among them, the width and position of the back transparent conductive layer 12 of the crystalline silicon solar cell 10 may be the same as those of the silicon wafer 15, or may be the same as those of the aforementioned front transparent conductive layer 43 and the intermediate transparent conductive layer 20. In a preferred embodiment, the width and position of the back transparent conductive layer 12 of the crystalline silicon solar cell 10 may be the same as those of the silicon wafer 15. Generally speaking, the effective area of the battery is determined by the overlapping part of the positive and negative electrodes. Figures 2 to 6The back transparent conductive layer 12 shown completely includes the front transparent conductive layer 43; therefore, the effective area is the front transparent conductive layer 43, and the area of ​​the back transparent conductive layer 12 that exceeds the front transparent conductive layer 43 is not included in the effective area. This back transparent conductive layer 12 is not patterned and completely covers the silicon wafer, effectively reducing process complexity.

[0062] like Figure 2 , Figure 5 as well as Figure 6 As shown, both main surfaces of the silicon wafer 15 have a textured structure, and the median of the Gaussian distribution of the base length of the pyramid structure formed by the textured structure is less than or equal to 4 μm. The main surfaces of the intermediate transparent conductive layer 20 and the metal oxide layer 30 are matched with the textured structure. It is worth noting that the median of the Gaussian distribution of the base length of the pyramid structure formed by this textured structure is greater than 0. This textured structure enables good compatibility between the intermediate transparent conductive layer 20 and the crystalline silicon solar cell, resulting in high transmittance and ultra-low longitudinal internal resistance, thereby improving the performance of the crystalline silicon perovskite tandem solar cell.

[0063] Furthermore, by controlling the size of the pyramid structure (i.e., the median of the Gaussian distribution of the base side length of the pyramid structure is less than or equal to 4 μm), the difficulty of depositing thin films such as intrinsic amorphous silicon layers, p-type amorphous silicon layers, n-type amorphous silicon layers, intermediate transparent conductive layers, metal oxide layers, and passivation layers can be reduced. If the size is too large, it is difficult to cover the entire film on its surface, and the exposed or incompletely covered areas can easily cause leakage current, reducing the yield and performance of the battery. Therefore, controlling the size of the pyramid structure can also ensure the integrity of the deposited film, reduce the risk of leakage current, and improve the performance and yield of the battery.

[0064] Furthermore, the thickness of the aforementioned transparent conductive layer 12 on the back can range from 0.05 μm to 200 μm. For example, the thickness of the transparent conductive layer 12 on the back can be 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 30 μm, 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 170 μm, 180 μm, 200 μm, etc. This wide range of thickness control for the transparent conductive layer 12 on the back facilitates fabrication and does not affect the performance of the crystalline silicon perovskite tandem solar cell.

[0065] The back transparent conductive layer 12 and the front transparent conductive layer 43 can also be any one or more combinations of indium tin oxide, indium tungsten oxide, indium zinc oxide, aluminum-doped zinc oxide, boron-doped zinc oxide, indium gallium zinc oxide, and magnesium-doped zinc oxide.

[0066] It is worth noting that the metal oxides and doped metals used in the back transparent conductive layer 12, the front transparent conductive layer 43, and the middle transparent conductive layer 20 may be the same or different.

[0067] like Figure 8 The method for fabricating a crystalline silicon perovskite tandem solar cell provided in the embodiments of the present invention may include the following steps:

[0068] Step S801: Fabricate a partial structure of a crystalline silicon solar cell 10 based on a silicon wafer.

[0069] The silicon wafer used in this step can have either a textured or planar surface; preferably, the silicon wafer has a textured surface. This step can be performed sequentially by deposition or sputtering. Figures 3 to 6 The first intrinsic amorphous silicon layer 14 and the second intrinsic amorphous silicon layer 16 are shown. Then, an n-type amorphous silicon layer is deposited or sputtered on the second intrinsic amorphous silicon layer 16, and a back transparent conductive layer is deposited or sputtered on the first intrinsic amorphous silicon layer 14. The ratio of the two metal elements (e.g., the ratio of indium to tin, the ratio of indium to tungsten, etc.) in the target material selected for the back transparent conductive layer can be adjusted according to actual needs.

[0070] In addition, in this step, a nano-silicon n-layer can be deposited on the n-type amorphous silicon layer by plasma-enhanced chemical vapor deposition, and then p-type nano-silicon can be deposited on the nano-silicon n-layer by plasma-enhanced chemical vapor deposition, thus achieving passivation of the n-type amorphous silicon layer.

[0071] Step S802: An intermediate transparent conductive layer 20 is prepared on the n-type amorphous silicon included in a portion of the structure of the crystalline silicon solar cell 10, wherein each edge of the intermediate transparent conductive layer 20 is recessed by a set distance relative to the edge of its adjacent crystalline silicon solar cell 10.

[0072] In this step, an intermediate transparent conductive layer, such as an indium tin oxide (ITO) layer, can be deposited on the n-type amorphous silicon layer side by magnetron sputtering. That is, for the unpassivated n-type amorphous silicon layer, the intermediate transparent conductive layer, such as the ITO layer, is directly deposited on the n-type amorphous silicon layer; for the passivated n-type amorphous silicon layer, the intermediate transparent conductive layer, such as the ITO layer, is directly deposited on the p-type nano-silicon surface.

[0073] Step S803: Prepare a metal oxide layer 30 on the intermediate transparent conductive layer 20 and on the area of ​​the crystalline silicon solar cell 10 not covered by the intermediate transparent conductive layer 20;

[0074] This step involves sputtering a metal-doped nickel oxide layer onto the intermediate transparent conductive layer using magnetron sputtering. The ratio of the two metals in the target material used for this magnetron sputtering method can be adjusted according to actual needs. For example, the target material used for magnetron sputtering is CuNiO (the mass ratio of the metal elements in this target material is Cu:Ni = 95:5).

[0075] Step S804: Fabricate a perovskite solar cell 40 on the metal oxide layer 30.

[0076] The method for fabricating the perovskite solar cell 40 can be as follows: sequentially fabricating the absorber layer 41, electron transport layer 42, front transparent conductive layer 43, and front conductive grid lines 44 included in the perovskite solar cell 40. Subsequently, back conductive grid lines 11 can be fabricated on one side of the crystalline silicon solar cell. This method for fabricating the perovskite solar cell 40 can be accomplished using existing technologies.

[0077] After step S803 and before step S804, the method may further include: preparing a passivation layer 50 on the metal oxide layer 30; correspondingly, a specific implementation of step S804 may include: preparing a perovskite solar cell 40 on the passivation layer 50.

[0078] The following describes several specific embodiments.

[0079] Example 1

[0080] A1. On the two main surfaces of an n-type silicon wafer with a polished planar structure and a thickness of 200 μm, an intrinsic amorphous silicon layer with a thickness of 8 nm and 10 nm is deposited by plasma-enhanced chemical vapor deposition.

[0081] A2. Deposit a layer of p-type amorphous silicon with a thickness of 15nm on an 8nm thick intrinsic amorphous silicon layer; deposit a layer of n-type amorphous silicon with a thickness of 20nm on a 10nm thick intrinsic amorphous silicon layer.

[0082] A3. Indium tin oxide (target material In:Sn = 90:10) was prepared on an n-type amorphous silicon layer by magnetron sputtering with a thickness of 20 nm. The sputtering area of ​​the indium tin oxide was 4 mm away from the edge of the silicon wafer.

[0083] A4. A CuNiO layer (target material Cu:Ni = 95:5) with a thickness of 30 nm was deposited on the indium tin oxide layer by magnetron sputtering.

[0084] A5. Lead iodide and cesium bromide were thermally evaporated and deposited onto the CuNiO surface deposited in A4 at rates of 0.105 nm / s and 0.015 nm / s, respectively. FAI and MABr were dissolved in anhydrous ethanol at a molar ratio of 10:1, with a total concentration of 1.5 mmol / ml. After complete dissolution, the solution was filtered through a 0.45 μm diameter polytetrafluoroethylene (PTFE) filter and then spin-coated onto the lead iodide film deposited in the previous step at 4000 rpm for 30 seconds. After spin-coating, the film was heated at 150°C and 50% relative humidity for 60 minutes to complete the perovskite film preparation. This perovskite film serves as the absorber layer for perovskite solar cells.

[0085] A6. A 20 nm fullerene and a 5 nm BCP are sequentially thermally evaporated onto the perovskite thin film, followed by atomic layer deposition to prepare a 20 nm thick tin oxide layer. This step forms the electron transport layer of the perovskite solar cell.

[0086] A7. A 100 nm thick layer of indium tin oxide is prepared on p-type amorphous silicon and an electron transport layer using reactive plasma deposition, wherein the width of the indium tin oxide prepared on the electron transport layer is the same as that in A3.

[0087] A8. Silver grid lines were fabricated using screen printing on the indium tin oxide layers at both ends. The height of the silver grid lines was 20 micrometers, and the width was 50 micrometers. The spacing between the silver grid lines was 2 millimeters. Figure 3 The structure shown.

[0088] Example 2

[0089] The only difference from Example 1 is that a doped nickel oxide layer is deposited by electron beam deposition after step A4. The result is as follows: Figure 4 The structure shown.

[0090] Example 3

[0091] The difference from Example 1 is that a 188μm thick n-type silicon wafer with a textured surface (double-sided textured surface size of 2μm) is selected. All other steps are the same as in Example 1, resulting in the following... Figure 5 The structure shown.

[0092] Comparative Example 1:

[0093] The difference from Example 3 is that:

[0094] The indium tin oxide layer was directly prepared on the n-type amorphous silicon layer using a solution spin-coating method with PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]), with a thickness of 5 nm. No doped nickel oxide layer was deposited.

[0095] Comparative Example 2:

[0096] The difference from Example 3 is that:

[0097] On the indium tin oxide layer on the n-type amorphous silicon side, molybdenum oxide (5 nm) and TATM (N,N,N',N'-tetra([1,1'-biphenyl]-4-yl)[1,1':4',1”-terphenyl]-4,4”-diamine, 10 nm) were sequentially thermally evaporated. No doped nickel oxide layer was deposited.

[0098] Comparative Example 3

[0099] The difference from Example 3 is that:

[0100] A NiO layer with a thickness of 30 nm was deposited on the indium tin oxide layer on the n-type amorphous silicon layer side by magnetron sputtering.

[0101] Comparative Example 4

[0102] The only difference from Example 1 is that steps A3 and A4 are replaced by: fabricating a 20 nm thick nano-silicon p-layer on n-type amorphous silicon by plasma-enhanced chemical vapor deposition, and then depositing another 20 nm thick n-type nano-silicon on the nano-silicon p-layer; that is, replacing the indium tin oxide and copper-doped nickel oxide layers in Example 1 with a p / n tunnel junction.

[0103] The open-circuit voltage, short-circuit current, fill factor, and battery efficiency of Examples 1 to 3 and Comparative Examples 1 to 4 were compared and analyzed. The comparison results are shown in Table 1 below.

[0104] Table 1

[0105] Open circuit voltage short circuit current Fill factor efficiency Example 1 102.50％ 87.56％ 103.44％ 92.83％ Example 2 104.08％ 85.21％ 100.02％ 88.70％ Example 3 100.00％ 100.00％ 100.00％ 100.00％ Comparative Example 1 41.19％ 95.90％ 88.75％ 35.05％ Comparative Example 2 89.23％ 97.21％ 83.33％ 72.28％ Comparative Example 3 102.80％ 93.04％ 75.32％ 74.05％ Comparative Example 4 105.65％ 86.94％ 98.47％ 90.44％

[0106] As shown in Table 1 above, compared with simply setting a passivation layer in the intermediate transparent conductive layer, setting a metal-doped nickel oxide layer or nickel oxide layer on the intermediate transparent conductive layer can effectively improve the open-circuit voltage, short-circuit current, fill factor and cell efficiency of crystalline silicon perovskite tandem solar cells.

[0107] Furthermore, the solution provided in this invention offers performance comparable to that of a p / n tunnel junction. However, compared to solar cells with p / n tunnel junctions, the crystalline silicon perovskite tandem solar cell and its fabrication method provided in this invention have a simpler process. They can be manufactured using existing conventional solar cell equipment, such as deposition equipment and spin-coating equipment, without requiring specialized production processes. This effectively reduces the cost of crystalline silicon perovskite tandem solar cells and makes their production more readily widespread.

[0108] The embodiments of the present invention provide the following technical solutions and combinations thereof.

[0109] Technical Solution 1: A crystalline silicon perovskite tandem solar cell, comprising: a crystalline silicon solar cell 10, an intermediate transparent conductive layer 20, a metal oxide layer 30, and a perovskite solar cell 40, stacked sequentially from bottom to top, wherein...

[0110] The intermediate transparent conductive layer 20 covers a portion of the crystalline silicon solar cell 10;

[0111] Each edge of the intermediate transparent conductive layer 20 is recessed by a set distance relative to the edge of its adjacent crystalline silicon solar cell 10;

[0112] The metal oxide layer 30 covers the intermediate transparent conductive layer 20 and the areas of the crystalline silicon solar cell 10 not covered by the intermediate transparent conductive layer 20.

[0113] Technical Solution 2: The crystalline silicon perovskite tandem solar cell according to Technical Solution 1, characterized in that,

[0114] The set distance is greater than or equal to 4mm.

[0115] Technical Solution 3: The crystalline silicon perovskite tandem solar cell according to Technical Solution 1, characterized in that...

[0116] The metal oxide layer 30 is a metal-doped nickel oxide layer.

[0117] Technical Solution 4: The crystalline silicon perovskite tandem solar cell according to Technical Solution 3, characterized in that the metal doped in the metal-doped nickel oxide layer includes:

[0118] Any one or more of copper, cobalt, manganese, lanthanum, yttrium, magnesium, lithium, zinc, indium, and tin.

[0119] Technical Solution 5: The crystalline silicon perovskite tandem solar cell according to Technical Solution 1 or 3, characterized in that,

[0120] The thickness of the metal oxide layer 30 is less than or equal to 100 nm.

[0121] Technical Solution 6: The crystalline silicon perovskite tandem solar cell according to Technical Solution 1 or 3, characterized in that it further includes: a passivation layer 50 disposed between the perovskite solar cell 40 and the metal oxide layer 30.

[0122] Technical Solution 7: The crystalline silicon perovskite tandem solar cell according to Technical Solution 1, characterized in that,

[0123] The thickness of the intermediate transparent conductive layer 20 is less than or equal to 50 nm.

[0124] Technical Solution 8: The crystalline silicon perovskite tandem solar cell according to Technical Solution 1, characterized in that,

[0125] The perovskite solar cell 40 includes, from bottom to top, an absorber layer 41, an electron transport layer 42, a front transparent conductive layer 43, and front conductive grid lines 44, wherein,

[0126] The front transparent conductive layer 43 covers a portion of the electron transport layer 42;

[0127] The indentation distance of each edge of the front transparent conductive layer 43 relative to the edge of its adjacent electron transport layer 42 is greater than or equal to 4 mm.

[0128] Technical Solution 9: The crystalline silicon perovskite tandem solar cell according to Technical Solution 1, characterized in that,

[0129] The crystalline silicon solar cell 10 includes, in order from bottom to top, a back conductive grid line 11, a back transparent conductive layer 12, a p-type amorphous silicon layer 13, a first intrinsic amorphous silicon layer 14, a silicon wafer 15, a second intrinsic amorphous silicon layer 16, and an n-type amorphous silicon layer 17.

[0130] Technical Solution 10: A crystalline silicon perovskite tandem solar cell according to Technical Solution 1 or 7, characterized in that the intermediate transparent conductive layer (20) comprises:

[0131] Any one or more combinations of indium tin oxide, indium tungsten oxide, indium zinc oxide, aluminum-doped zinc oxide, boron-doped zinc oxide, indium gallium zinc oxide, and magnesium-doped zinc oxide.

[0132] Technical Solution 11: The crystalline silicon perovskite tandem solar cell according to Technical Solution 6, characterized in that,

[0133] The passivation layer 50 is a single-layer or multilayer structure formed from any one or more of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], benzyl iodide, hexyltrimethylammonium bromide, polymethyl methacrylate, and 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone.

[0134] Technical Solution 12: The crystalline silicon perovskite tandem solar cell according to Technical Solution 8, characterized in that,

[0135] The projection of the main surface of the front transparent conductive layer 43 coincides with the projection of the main surface of the middle transparent conductive layer 20.

[0136] Technical Solution 13: The crystalline silicon perovskite tandem solar cell according to Technical Solution 9, characterized in that,

[0137] Both main surfaces of the silicon wafer 15 have a textured surface, and the median of the Gaussian distribution of the base side length of the pyramid structure formed by the textured surface is less than or equal to 4 μm.

[0138] Technical Solution 14: The crystalline silicon perovskite tandem solar cell according to Technical Solution 13, characterized in that,

[0139] The main surfaces of the intermediate transparent conductive layer 20 and the metal oxide layer 30 are matched with the textured surface structure.

[0140] Technical Solution 15: The crystalline silicon perovskite tandem solar cell according to Technical Solution 8, characterized in that,

[0141] The absorber layer 41 comprises: MAPbI3, FAPbI3, and Cs. x (FA y MA 1-y ) 1-x Pb(I z Br 1-z Any one of the following three, where 0 < x ≤ 0.2 or 0.5 <y≤1、0.75≤z<1。

[0142] Technical Solution 16. The crystalline silicon perovskite tandem solar cell according to Technical Solution 8, characterized in that,

[0143] The thickness of the front transparent conductive layer 43 is in the range of 50nm to 200nm.

[0144] Technical Solution 17: The crystalline silicon perovskite tandem solar cell according to Technical Solution 9, characterized in that,

[0145] The thickness of the transparent conductive layer 12 on the back side is in the range of 0.05 μm to 200 μm.

[0146] The method for preparing crystalline silicon perovskite tandem solar cells according to any one of technical solutions 18 and 1 to 17 is characterized in that it includes:

[0147] Step 1: Fabricate a partial structure of a crystalline silicon solar cell 10 based on a silicon wafer;

[0148] Step 2: An intermediate transparent conductive layer 20 is prepared on the n-type amorphous silicon included in a portion of the structure of the crystalline silicon solar cell 10, wherein each edge of the intermediate transparent conductive layer 20 is recessed by a set distance relative to the edge of its adjacent crystalline silicon solar cell 10.

[0149] Step 3: Prepare a metal oxide layer 30 on the intermediate transparent conductive layer 20 and on the area of ​​the crystalline silicon solar cell 10 not covered by the intermediate transparent conductive layer 20;

[0150] Step 4: Fabricate a perovskite solar cell 40 on the metal oxide layer 30.

[0151] Technical Solution 19: The preparation method according to Technical Solution 18, characterized in that,

[0152] After step 3 and before step 4, the method further includes: step 3', preparing a passivation layer 50 on the metal oxide layer 30;

[0153] Step 4 includes: fabricating a perovskite solar cell 40 on the passivation layer 50.

[0154] The above steps are provided only to help understand the method, structure, and core ideas of this invention. Those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims.

Claims

1. A crystalline silicon perovskite tandem solar cell, characterized in that, include: The layers stacked from bottom to top are a crystalline silicon solar cell (10), a middle transparent conductive layer (20), a metal oxide layer (30), and a perovskite solar cell (40), wherein... The intermediate transparent conductive layer (20) covers a portion of the crystalline silicon solar cell (10); Each edge of the intermediate transparent conductive layer (20) is recessed by a set distance relative to the edge of its adjacent crystalline silicon solar cell (10); The metal oxide layer (30) covers the intermediate transparent conductive layer (20) and the area of ​​the crystalline silicon solar cell (10) not covered by the intermediate transparent conductive layer (20); The set distance is greater than or equal to 4 mm, and the length and width of the crystalline silicon perovskite tandem solar cell are both set to α mm. The minimum length and width of the required intermediate transparent conductive layer (20) are both β mm. Then set the distance to 4~ Any value in mm.

2. The crystalline silicon perovskite tandem solar cell according to claim 1, characterized in that, The metal oxide layer (30) is a metal-doped nickel oxide layer.

3. The crystalline silicon perovskite tandem solar cell according to claim 2, characterized in that, The metal doped in the metal-doped nickel oxide layer includes: Any one or more of copper, cobalt, manganese, lanthanum, yttrium, magnesium, lithium, zinc, indium, and tin.

4. The crystalline silicon perovskite tandem solar cell according to claim 1 or 2, characterized in that, The thickness of the metal oxide layer (30) is less than or equal to 100 nm.

5. The crystalline silicon perovskite tandem solar cell according to claim 1 or 2, characterized in that, Also includes: A passivation layer (50) is disposed between the perovskite solar cell (40) and the metal oxide layer (30).

6. The crystalline silicon perovskite tandem solar cell according to claim 5, characterized in that, The passivation layer (50) is a single-layer or multilayer structure formed from any one or more of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], benzyl iodide, hexyltrimethylammonium bromide, polymethyl methacrylate and 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone].

7. The crystalline silicon perovskite tandem solar cell according to claim 1, characterized in that, The thickness of the intermediate transparent conductive layer (20) is less than or equal to 50 nm.

8. The crystalline silicon perovskite tandem solar cell according to claim 1, characterized in that, The intermediate transparent conductive layer (20) includes any one or more combinations of indium tin oxide, indium tungsten oxide, indium zinc oxide, aluminum-doped zinc oxide, boron-doped zinc oxide, indium gallium zinc oxide, and magnesium-doped zinc oxide.

9. The crystalline silicon perovskite tandem solar cell according to claim 1, characterized in that, The perovskite solar cell (40) comprises, from bottom to top, an absorber layer (41), an electron transport layer (42), a front transparent conductive layer (43), and front conductive grid lines (44), wherein, The front transparent conductive layer (43) covers a portion of the electron transport layer (42); The indentation distance of each edge of the front transparent conductive layer (43) relative to the edge of its adjacent electron transport layer (42) is greater than or equal to 4 mm.

10. The crystalline silicon perovskite tandem solar cell according to claim 9, characterized in that, The projection of the main surface of the front transparent conductive layer (43) coincides with the projection of the main surface of the middle transparent conductive layer (20).

11. The crystalline silicon perovskite tandem solar cell according to claim 9, characterized in that, The absorber layer (41) comprises: MAPbI3, FAPbI3, Cs x (FA y MA 1-y ) 1-x Pb(I z Br 1-z Any one of the following three, where 0 < x ≤ 0.2 or 0.5 <y≤1、0.75≤z<1。 12. The crystalline silicon perovskite tandem solar cell according to claim 9, characterized in that, The thickness of the front transparent conductive layer (43) is in the range of 50nm to 200nm.

13. The crystalline silicon perovskite tandem solar cell according to claim 1, characterized in that, The crystalline silicon solar cell (10) includes, in order from bottom to top, a back conductive grid line (11), a back transparent conductive layer (12), a p-type amorphous silicon layer (13), a first intrinsic amorphous silicon layer (14), a silicon wafer (15), a second intrinsic amorphous silicon layer (16), and an n-type amorphous silicon layer (17).

14. The crystalline silicon perovskite tandem solar cell according to claim 13, characterized in that, Both main surfaces of the silicon wafer (15) are textured, and the median of the Gaussian distribution of the base side length of the pyramid structure formed by the textured structure is less than or equal to 4 μm.

15. The crystalline silicon perovskite tandem solar cell according to claim 14, characterized in that, The main surface of the intermediate transparent conductive layer (20) and the main surface of the metal oxide layer (30) are matched with the textured structure.

16. The crystalline silicon perovskite tandem solar cell according to claim 13, characterized in that, The thickness of the back transparent conductive layer (12) is in the range of 0.05μm to 200μm.

17. The method for preparing a crystalline silicon perovskite tandem solar cell according to any one of claims 1 to 8, characterized in that, include: Step 1: Fabrication of a partial structure of a crystalline silicon solar cell (10) based on a silicon wafer; Step 2, an intermediate transparent conductive layer (20) is prepared on the n-type amorphous silicon included in a portion of the structure of the crystalline silicon solar cell (10), wherein each edge of the intermediate transparent conductive layer (20) is recessed by a set distance relative to the edge of its adjacent crystalline silicon solar cell (10); Step 3: Prepare a metal oxide layer (30) on the intermediate transparent conductive layer (20) and on the area of ​​the crystalline silicon solar cell (10) not covered by the intermediate transparent conductive layer (20). Step 4: Fabricate a perovskite solar cell (40) on the metal oxide layer (30).

18. The preparation method according to claim 17, characterized in that, After step 3 and before step 4, the method further includes: step 3', preparing a passivation layer (50) on the metal oxide layer (30); Step 4 includes: fabricating a perovskite solar cell (40) on the passivation layer (50).

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