Method for manufacturing tandem solar cell

Abstract

The present invention relates to a method for manufacturing a tandem solar cell. In addition, the present invention comprises the steps of: forming a CIGS thin-film solar cell on one surface of a substrate; and forming a perovskite solar cell on the other surface of the substrate having the CIGS thin-film solar cell formed thereon, wherein the steps are continuously performed by a roll-to-roll sputtering process, thereby simplifying the manufacturing process and facilitating mass production.

Description

Tandem solar cell manufacturing method

[0001] The present invention relates to a method for manufacturing a tandem solar cell.

[0002] In general, solar cells are a collection of devices that convert solar energy into electricity. They are attracting attention as a next-generation energy source and have been studied for a long time. The solar cells that are currently commercialized and most widely used are single-junction crystalline silicon solar cells.

[0003] However, due to the low photoelectric conversion efficiency of crystalline silicon solar cells, development of tandem solar cells that form a single solar cell by connecting single-junction solar cells containing absorbing layers with different band gaps is actively underway.

[0004] These tandem solar cells have an upper cell with a large band gap that absorbs solar energy in the low wavelength range, and a lower cell with a low band gap that absorbs solar energy in the high wavelength range, thereby reducing loss and operating solar energy in a wide wavelength range, and thus can achieve a high photovoltaic efficiency of over 30% that cannot be obtained from existing crystalline silicon solar cells. In particular, silicon / perovskite tandem solar cells have a small band gap and a large band gap, respectively, which are advantageous for optical operation, and are therefore actively researched.

[0005] However, there is a problem that the manufacturing process is complicated and expensive due to the use of various processes such as sputtering process, wet chemical process, simultaneous vacuum evaporation method, and solution process in the manufacturing of silicon / perovskite tandem solar cells.

[0006] In addition, in the case of perovskite, there is a problem that damage to the crystal structure may occur when applying the sputtering process.

[0007] Meanwhile, the technology underlying the present invention is published in Patent Publication Nos. 10-2020-0127685 and 10-2018-0130397.

[0008] The present invention has been conceived in consideration of the above-mentioned problems, and its purpose is to provide a method for manufacturing a tandem solar cell that is easy to mass-produce and has a simplified manufacturing process.

[0009] In addition, the present invention aims to provide a method for manufacturing a tandem solar cell capable of reducing or preventing damage to the crystal structure of perovskite.

[0010] The purposes of the present invention are not limited to the purposes mentioned above, and other purposes not mentioned will be clearly understood by those skilled in the art from the description below.

[0011] In order to achieve the above-described purpose, the present invention provides a method for manufacturing a tandem solar cell, comprising the steps of forming a CIGS thin film solar cell on one side of a substrate; and the step of forming a perovskite solar cell on the other side of the substrate on which the CIGS thin film solar cell is formed; wherein the steps are continuously performed by a roll-to-roll sputtering process.

[0012] In a preferred embodiment, the step of forming the CIGS thin film solar cell includes sequentially performing a deposition process of a rear electrode layer, an absorption layer, a buffer layer, and a front electrode layer by a plurality of different targets provided on a moving path of the substrate.

[0013] In a preferred embodiment, the step of forming the perovskite solar cell includes sequentially performing a deposition process of an upper electrode layer, an electron transport layer, a perovskite absorption layer, a hole transport layer, and a lower electrode layer by a plurality of different targets provided on a moving path of the substrate.

[0014] In a preferred embodiment, the step of forming the perovskite solar cell includes a deposition process of the perovskite absorber layer performed by facing target sputtering.

[0015] By the above-described problem-solving means, the present invention has the effect of simplifying the manufacturing process and facilitating mass production because the processes of forming CIGS thin film solar cells and perovskite solar cells on a substrate are continuously performed by a roll-to-roll sputtering process.

[0016] In addition, the present invention has the effect of reducing or preventing damage to the crystal structure of perovskite compared to a general sputtering method by depositing perovskite using a counter-target sputtering method.

[0017] Fig. 1 is a drawing showing the cross-sectional structure of a tandem solar cell according to the present invention.

[0018] Figure 2 is a flow chart of a tandem solar cell manufacturing method according to the present invention.

[0019] Figure 3 is a drawing schematically showing manufacturing equipment used in a tandem solar cell manufacturing method according to the present invention.

[0020] FIG. 4 is a drawing schematically illustrating an opposed target sputtering process used in a tandem solar cell manufacturing method according to the present invention.

[0021] In the following description, specific details of the present invention are set forth to provide a general understanding of the present invention, but it will be apparent to those skilled in the art that the present invention may be readily practiced without these specific details and with modifications thereof.

[0022] Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the attached drawings 1 to 4, focusing on the parts necessary for understanding the operation and function according to the present invention.

[0023]

[0024] FIG. 1 is a drawing showing a cross-sectional structure of a tandem solar cell according to the present invention.

[0025] Referring to FIG. 1, a tandem solar cell (100) according to one embodiment of the present invention may be configured to include a substrate (110), a CIGS thin film solar cell (120), and a perovskite solar cell (130).

[0026] The substrate (110) is made of a plastic material including a synthetic resin, or a metal material including stainless steel (SUS), aluminum (Al), and titanium (Ti), and can be flexibly formed in a thin plate shape. In addition to the presented materials, the substrate (110) may also use other equivalent materials that are flexible, have low oxygen and moisture permeability, and are less susceptible to mechanical damage.

[0027] Such a substrate (110) is supplied in a roll form and when the process of forming a CIGS thin film solar cell (120) and a perovskite solar cell (130) is continuously performed, it can be recovered in a roll form again.

[0028] The above CIGS thin film solar cell (120) can be formed on one side of the substrate (110), for example, the front side, and can be formed in a structure in which a rear electrode layer (121), an absorption layer (122), a buffer layer (123), and a front electrode layer (124) are sequentially laminated.

[0029] In addition, the rear electrode layer (121) is formed on the front surface of the substrate (110) and can be formed by a sputtering process targeting at least one of titanium (Ti), molybdenum (Mo), molybdenum-sodium (MoNa), and chromium (Cr).

[0030] In addition, the absorption layer (122) is formed on the rear electrode layer (121) and is electrically connected to the rear electrode layer (121), and is provided to absorb light energy and produce photovoltaic power. It can be formed by a sputtering process using each element of copper (Cu), indium (In), gallium (Ga), and selenium (Se) as a target, or using a CIGS single target. At this time, a heat treatment process such as annealing may be performed.

[0031] In addition, the buffer layer (123) is formed on the absorption layer (122) and is electrically connected to the absorption layer (122) and the front electrode layer, and is provided to produce photovoltaic power together with the absorption layer (122), and can be formed by a sputtering process targeting at least one of cadmium sulfide (Cds), zinc sulfide (ZnS), and zinc oxide (ZnOx).

[0032] In addition, the front electrode layer (124) is a transparent electrode formed on the buffer layer (123) and electrically connected to the buffer layer (123), and can be formed by a sputtering process targeting at least one of indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), and intrinsic-ZnO (i-ZnO).

[0033] The above perovskite solar cell (130) can be formed on another surface of the substrate (110), for example, the back surface, and can be formed in a structure in which an upper electrode layer (131), an electron transport layer (132), a perovskite absorption layer (133), a hole transport layer (134), and a lower electrode layer (135) are sequentially laminated.

[0034] In addition, the upper electrode layer (131) is a transparent electrode formed on the back surface of the substrate (110), and can be formed by a sputtering process targeting Fluorine-doped Tin Oxide (FTO).

[0035] In addition, the electron transport layer (132) is formed on the upper electrode layer (131) and can be formed by a sputtering process targeting methyl-substituted carbazole (Me-4PACz).

[0036] In addition, the perovskite absorption layer (133) is formed on the electron transport layer (132), and allows the hole-electron pair generated by receiving light energy to be separated into electrons or holes. At this time, the electrons can be transferred to the electron transport layer (132) and the holes can be transferred to the hole transport layer (134).

[0037] Such a perovskite absorption layer (133) can be formed by a sputtering process targeting perovskite, and in particular, can be deposited by a facing target sputtering method to reduce or prevent damage to the crystal structure in the sputtering process.

[0038] In addition, the hole transport layer (134) is formed on the perovskite absorption layer (133) and can be formed by a sputtering process targeting at least one of tin oxide (SNO2) and buckminsterfullerene (C60).

[0039] In addition, the lower electrode layer (135) is a transparent electrode formed on the hole transport layer (134), and can be formed by a sputtering process targeting Indium Zinc Oxide (IZO).

[0040] In this way, a tandem solar cell (100) according to one embodiment of the present invention may have a CIGS thin film solar cell (120) formed on the upper side of a substrate (110) and a perovskite solar cell (130) formed on the lower side of the substrate (110), but is not limited thereto.

[0041] Below, a process for manufacturing a tandem solar cell according to an embodiment of the present invention is described.

[0042]

[0043] FIG. 2 is a flowchart for a tandem solar cell manufacturing method according to the present invention, FIG. 3 is a drawing schematically showing manufacturing equipment used in the tandem solar cell manufacturing method according to the present invention, and FIG. 4 is a drawing schematically explaining an opposing target sputtering process used in the tandem solar cell manufacturing method according to the present invention.

[0044] Referring to FIGS. 2 to 4, a tandem solar cell manufacturing method according to one embodiment of the present invention first forms a CIGS thin film solar cell (120) on one surface of a substrate (110) (S110).

[0045] In step S110, the substrate (110) may be made of a plastic material including a synthetic resin, a metal material including stainless steel (SUS), aluminum (Al), and titanium (Ti), and may be supplied in a roll form and recovered again in a roll form.

[0046] In this way, when the substrate (110) is supplied, the roll-to-roll sputtering process for forming a CIGS thin film solar cell (120) and a perovskite solar cell (130) can be continuously performed.

[0047] Preferably, in step S110, the deposition process of the rear electrode layer (121), the absorption layer (122), the buffer layer (123), and the front electrode layer (124) may be sequentially performed by a plurality of different targets provided on the moving path of the substrate (110). At this time, a heat treatment process such as annealing may be performed.

[0048] In addition, the rear electrode layer (121) can be formed by a sputtering process targeting at least one of titanium (Ti), molybdenum (Mo), molybdenum-sodium (MoNa), and chromium (Cr), the absorbing layer (122) can be formed by a sputtering process targeting each element of copper (Cu), indium (In), gallium (Ga), and selenium (Se) or using a CIGS single target, the buffer layer (123) can be formed by a sputtering process targeting at least one of cadmium sulfide (Cds), zinc sulfide (ZnS), and zinc oxide (ZnOx), and the front electrode layer (124) can be formed by a sputtering process targeting at least one of indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), and intrinsic-ZnO (i-ZnO).

[0049] Next, a perovskite solar cell (130) is formed on a substrate (110) on which a CIGS thin film solar cell (120) is formed. At this time, the deposition processes of the upper electrode layer (131), the electron transport layer (132), the perovskite absorption layer (133), the hole transport layer (134), and the lower electrode layer (135) can be sequentially performed by a plurality of different targets provided on the movement path of the substrate (110).

[0050] First, an upper electrode layer (131) and an electron transport layer (132) for forming a perovskite solar cell (130) are formed on the other side of the substrate (110) on which the CIGS thin film solar cell (120) is formed (S210).

[0051] In step S210, the surface on which the sputtering process is performed on the substrate (110) can be switched, and for example, the deposition of the upper electrode layer (131) and the electron transport layer (132) can be performed on the back surface, i.e., the opposite surface, of the substrate (110) on which the CIGS thin film solar cell (120) is formed.

[0052] In addition, the upper electrode layer (131) may be formed by a sputtering process targeting fluorine-doped tin oxide (FTO), and the electron transport layer (132) may be formed by a sputtering process targeting methyl-substituted carbazole (Me-4PACz). At this time, a heat treatment process such as annealing may be performed.

[0053] Next, a perovskite absorption layer (133) is formed on the electron transport layer (132) (S220).

[0054] In step S220, as illustrated in FIG. 4, the deposition process of the perovskite absorber layer (133) can be performed using a facing target sputtering method in which two sputter cathodes are positioned facing each other, and two targets are respectively positioned perpendicular to the substrate (110) for each sputter cathode. This makes it possible to minimize or prevent physical and thermal damage to the crystal structure of the perovskite absorber layer (133) compared to a general sputtering process.

[0055] Next, a hole transport layer (134) and a lower electrode layer (135) are formed on the perovskite absorption layer (133) (S230).

[0056] In step S230, the hole transport layer (134) can be formed by a sputtering process targeting at least one of tin oxide (SNO2) and buckminsterfullerene (C60), the lower electrode layer (135) can be formed by a sputtering process targeting indium zinc oxide (IZO), and a heat treatment process such as annealing can be performed during the formation of the lower electrode layer (135).

[0057] By completing step S230, the substrate (110) on which the CIGS thin film solar cell (120) and the perovskite solar cell (130) are formed on each side can be recovered in a roll form again.

[0058] As such, the tandem solar cell manufacturing method according to one embodiment of the present invention can simplify the manufacturing process, facilitate mass production, and reduce or prevent damage to the crystal structure of perovskite.

[0059] Although the preferred embodiments of the present invention have been described above as examples, the scope of the present invention is not limited to these specific embodiments, and may be appropriately modified within the scope described in the claims.

[0060] The present invention can be applied to a manufacturing process of a tandem solar cell composed of a CIGS thin film solar cell and a perovskite solar cell.

Claims

1. A step of forming a CIGS thin film solar cell on one side of a substrate; and A step of forming a perovskite solar cell on the other side of the substrate on which the CIGS thin film solar cell is formed; A tandem solar cell manufacturing method characterized in that the above steps are performed continuously by a roll-to-roll sputtering process.

2. In paragraph 1, The step of forming the above CIGS thin film solar cell is: A tandem solar cell manufacturing method characterized in that the deposition processes of a rear electrode layer, an absorption layer, a buffer layer, and a front electrode layer are sequentially performed by a plurality of different targets provided on the moving path of the substrate.

3. In paragraph 1, The step of forming the above perovskite solar cell is: A tandem solar cell manufacturing method characterized in that the deposition processes of an upper electrode layer, an electron transport layer, a perovskite absorption layer, a hole transport layer, and a lower electrode layer are sequentially performed by a plurality of different targets provided on the moving path of the substrate.

4. In paragraph 3, The step of forming the above perovskite solar cell is: A tandem solar cell manufacturing method characterized in that the deposition process of the perovskite absorbing layer is performed using a facing target sputtering method.

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