Perovskite tandem solar cell

Abstract

The present invention provides a perovskite tandem solar cell comprising: a substrate; a first electrode layer disposed on the substrate; a silicon layer disposed on the first electrode layer; a hole transport layer disposed on the silicon layer; a self-assembled monolayer (SAM) disposed on the hole transport layer; a perovskite layer disposed on the self-assembled monolayer; an electron transport layer disposed on the perovskite layer; and a second electrode layer disposed on the electron transport layer; wherein the self-assembled monolayer comprises a carbazole compound containing a phosphonic acid anchor group and a mercapto compound, and the interlayer structure is maintained by combining with the perovskite layer and the hole transport layer.

Description

Technology Field

[0001] The present invention relates to a perovskite tandem solar cell. More specifically, the present invention relates to a perovskite tandem solar cell in which the hole transport layer is stabilized. Background Technology

[0003] Generally, tandem solar cells can utilize solar energy over a wide wavelength range more effectively by vertically stacking light-absorbing layers with different band gaps.

[0004] Recently, perovskite tandem solar cells have been gaining attention. Silicon solar cells absorb long wavelengths and perovskite solar cells absorb short wavelengths, and because they absorb different wavelengths of sunlight, they can achieve high photovoltaic conversion efficiency (PCE).

[0005] The theoretical limiting efficiency of perovskite tandem solar cells reaches 44%, which is higher than that of silicon solar cells and perovskite solar cells.

[0006] Meanwhile, in inverted-structure PIN perovskite solar cells, nickel oxide (NiO₂) is mainly used as the hole transport layer. x A metal oxide such as ) is selected, and in this case, a method to stabilize the hole transport layer is required.

[0007] In particular, there is an urgent need to develop a method to bond a hole transport layer to a textured perovskite solar cell and maintain the interlayer structure stably. Prior art literature

[0009] Republic of Korea Published Patent Application No. 10-2015-0122598 The problem to be solved

[0010] The objective of the present invention is to provide a perovskite tandem solar cell with greatly increased photoelectric conversion efficiency by further stabilizing the hole transport layer containing a metal oxide and joining a silicon solar cell and a perovskite solar cell.

[0011] Another objective of the present invention is to provide a solar cell module comprising the perovskite tandem solar cell.

[0012] The above and other objectives of the present invention can all be achieved by the present invention described below. means of solving the problem

[0014] 1. One aspect of the present invention relates to a perovskite solar cell for tandem solar cells.

[0015] The above perovskite solar cell comprises a metal oxide layer;

[0016] A self-assembled monolayer formed on the metal oxide layer; and

[0017] A perovskite layer formed on the self-assembled monolayer; comprising

[0018] The self-assembled monolayer comprises a carbazole compound and a mercapto compound containing a phosphonic acid anchor group.

[0019] 2. In the above 1 embodiment, the metal oxide layer may further include a conductive metal layer.

[0020] 3. In the above 1 or 2 embodiments, the molar ratio of (a) a carbazole compound containing a phosphonic acid anchor group and (b) a mercapto compound may be (a) : (b) = 1 : 0.005 to 1.

[0021] 4. In the above 3 embodiments, the carbazole compound is one or more of Me-4PACz, MeO-2PACz and 2PACz, and the mercapto compound may be 3-mercaptopropionic acid.

[0022] 5. In any one of the embodiments 1 to 4 above, the carbazole functional group of the carbazole compound may be bonded to the perovskite film, and the phosphonic acid anchor group may be bonded to the metal oxide layer.

[0023] 6. Another aspect of the present invention provides a perovskite tandem solar cell comprising a perovskite solar cell.

[0024] The above perovskite tandem solar cell is

[0025] Substrate;

[0026] A first electrode layer disposed on the above substrate;

[0027] A silicon layer provided on the first electrode layer;

[0028] A hole transport layer provided on the above silicon layer;

[0029] Self-assembled monolayers (SAMs) provided on the hole transport layer above;

[0030] A perovskite layer provided on the self-assembled monolayer above;

[0031] An electron transport layer provided on the perovskite layer above; and

[0032] A second electrode layer provided on the electron transport layer; comprising

[0033] The self-assembled monolayer comprises a carbazole compound and a mercapto compound containing a phosphonic acid anchor group, and the interlayer structure is maintained by combining with the perovskite layer and the hole transport layer.

[0034] 7. In the above 6 embodiments, the first electrode layer may include a transparent electrode and a first electrode.

[0035] 8. In the above 6 or 7 embodiments, a buffer layer containing LiF may be further included between the perovskite layer and the electron transport layer.

[0036] 9. In any one of the embodiments 6 to 8 above, the carbazole compound is one or more of Me-4PACz, MeO-2PACz and 2PACz, and the mercapto compound may be 3-mercaptopropionic acid.

[0037] 10. In the above 9 embodiments, the carbazole functional group of the carbazole compound may bond with the perovskite layer, and the phosphonic acid anchoring group may bond with the metal oxide.

[0038] 11. In the above 10 embodiments, the mercapto compound may be interposed between the carbazole compounds to reduce the spacing between the compounds.

[0039] 12. In any one of the embodiments 6 to 11 above, the self-assembled monolayer may contain the mercapto compound in an amount of 0.005 mM to 1 mM.

[0040] 13. In any one of the embodiments 6 to 12 above, the contact angle of the self-assembled monolayer with respect to deionized water may be 70° to 80°.

[0041] 14. In any one of the embodiments 6 to 13 above, the hole transport layer may include a metal oxide layer and a conductive metal layer.

[0042] 15. In the above 14 embodiments, the metal oxide layer is NiO x It may include.

[0043] 16. In any one of the embodiments 6 to 15 above, the electron transport layer is C60 fullerene / SnO x It may include a double layer.

[0044] 17. In any one of the embodiments 6 to 16 above, the second electrode layer may have a metal electrode arranged on a conductive metal layer.

[0045] 18. In any one of the embodiments 6 to 17 above, the front and back surfaces of the perovskite layer may be textured.

[0046] 19. Another aspect of the present invention relates to a tandem solar cell module comprising the perovskite tandem solar cell.

[0047] The above tandem solar cell module includes a perovskite tandem solar cell, and

[0048] The second electrode layer is electrically connected to the first electrode layer of the adjacent perovskite tandem solar cell. Effects of the invention

[0050] The silicon perovskite solar cell according to the present invention can form a more stable interlayer structure by placing a self-assembled monolayer (SAM) on a metal oxide layer selected as a hole transfer layer of an inverted PIN cell, so that the terminal groups of the self-assembled monolayer combine with the perovskite film.

[0051] By placing a self-assembled monolayer on the hole transport layer of a silicon solar cell, a perovskite solar cell can be directly bonded onto the silicon solar cell using a method such as solution deposition. Since the self-assembled monolayer is flexible and can form various structures, it can be stably bonded onto a silicon solar cell having a curved surface, thereby enabling the fabrication of high-quality silicon perovskite solar cells with high power conversion efficiency in various shapes. Brief explanation of the drawing

[0053] FIG. 1 is a schematic diagram of a perovskite solar cell according to one embodiment of the present invention. FIG. 2 is a schematic diagram of a perovskite tandem solar cell according to one embodiment of the present invention. FIG. 3 shows the bonding state of a self-assembled monolayer to a metal oxide layer in a perovskite tandem solar cell according to one embodiment of the present invention. FIG. 4 shows the contact angle measurement results for deionized water of a self-assembled monolayer in a perovskite tandem solar cell according to one embodiment of the present invention. Specific details for implementing the invention

[0054] The present invention will be described in more detail below with reference to the attached drawings. However, the following drawings are provided merely to aid in understanding the present invention, and the present invention is not limited by the drawings. Furthermore, the shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings are exemplary, and the present invention is not limited to the depicted details.

[0055] Throughout the specification, the same reference numerals refer to the same components. Additionally, in describing the present invention, detailed descriptions of related prior art are omitted if it is determined that such detailed descriptions would unnecessarily obscure the essence of the invention.

[0056] Where terms such as 'includes,' 'have,' and 'consists of' are used in this specification, other parts may be added unless 'only' is used. Where a component is expressed in the singular, it includes cases where it includes the plural unless specifically stated otherwise.

[0057] In interpreting the components, they are interpreted to include a margin of error even in the absence of a separate explicit statement.

[0058] In this specification, "a to b" indicating a numerical range is defined as "≥a and ≤b".

[0059] In this specification, all numerical ranges include a 95% standard error range.

[0061] One aspect of the present invention relates to a perovskite solar cell for tandem solar cells.

[0062] FIG. 1 is a schematic diagram of a perovskite solar cell for a tandem solar cell according to one embodiment of the present invention.

[0063] Referring to FIG. 1, the perovskite solar cell can be configured as a perovskite tandem solar cell including a silicon solar cell.

[0064] The above perovskite solar cell includes a metal oxide layer (420), a self-assembled monolayer (500), and a perovskite layer (600).

[0065] The above perovskite solar cell may be an inverted PIN solar cell and may comprise a hole transport layer (400) including a metal oxide layer (420).

[0066] Specifically, the above-mentioned perovskite solar cell is nickel oxide (NiO₂) to form a tandem solar cell. x The same metal oxide layer (420) containing ) is included as a hole transport layer (400).

[0067] The self-assembled monolayer (500) is formed on the metal oxide layer (420).

[0068] The conductive metal layer (410) can support the metal oxide layer (420).

[0069] The above perovskite layer (600) is formed on the above self-assembled monolayer (500).

[0070] A self-assembled monolayer (500) is interposed between the metal oxide layer (420) and the perovskite layer (600), so that the metal oxide layer (420) can be bonded to the perovskite layer (600).

[0071] The above self-assembled monolayers (SAMs; 500) refer to organic monolayers that are spontaneously formed on a solid surface and may include a head group that anchors to other chemical species, a spacer composed of a hydrocarbon chain, and an end group that performs the role of a functional group. By selecting the end group, self-assembled monolayers (500) of various properties can be formed.

[0072] In one embodiment, the self-assembled monolayer (500) may include a carbazole compound containing a phosphonic acid anchor group and a mercapto compound. Specifically, the molar ratio of (a) a carbazole compound containing a phosphonic acid anchor group and (b) a mercapto compound may be (a) : (b) = 1 : 0.005 to 1.

[0073] In the above range, when the carbazole compound and the mercapto compound are included, the phosphoic acid anchor group of the carbazole compound reacts with the metal oxide film as a head group to very effectively form a monomolecular layer on top of the oxide film, and the end group, which is a functional group, combines with the perovskite layer (600) to greatly improve the interlayer structural stability.

[0074] Specifically, the carbazole compound is one or more of Me-4PACz, MeO-2PACz, and 2PACz, and the mercapto compound may be 3-mercaptopropionic acid.

[0075] The phosphonic acid anchor group of the above carbazole compound reacts with the metal oxide film to form a monolayer, and the carbazole combines with the perovskite layer (600) to form a self-assembled monolayer (500) which can improve the interlayer structural stability of the metal oxide layer (420) and the perovskite layer (600).

[0076] The metal oxide layer (420) may further include a conductive metal layer (410).

[0077] A conductive metal layer (410) may be provided on one side of the metal oxide layer (420) to form a double layer hole transport layer (400). The conductive metal layer (410) electrically connects a silicon solar cell including a silicon layer (300) and a perovskite solar cell including a perovskite layer (600), and can regulate the charge balance of charges and holes.

[0078] The above conductive metal layer (410) is provided to improve charge carrier transport efficiency and to effectively configure a perovskite tandem solar cell including a silicon solar cell.

[0079] The above perovskite solar cell includes a metal oxide as a hole transport layer (400), and the hole transport layer (400) can be stabilized as a self-assembled monolayer (500), and can be combined with a silicon solar cell to form a tandem solar cell, and the power conversion efficiency can be greatly improved compared to the silicon solar cell.

[0080] Another aspect of the present invention provides a perovskite tandem solar cell (1000) comprising a perovskite solar cell.

[0081] FIG. 2 is a schematic diagram of a perovskite tandem solar cell (1000) according to one embodiment of the present invention, and FIG. 3 shows the bonding state of a self-assembled monolayer (500) to a metal oxide layer (420) in a perovskite tandem solar cell (1000) according to one embodiment of the present invention.

[0082] Referring to FIGS. 2 and 3, the perovskite tandem solar cell (1000) comprises a substrate (100), a first electrode layer (200), a silicon layer (300), a hole transport layer (400), a self-assembled monolayer (500), a perovskite layer (600), an electron transport layer (800), and a second electrode layer (900).

[0083] The substrate (100) provides a space in which the first electrode (210), silicon layer (300), perovskite layer (600), and second electrode (900) are disposed, and can protect the silicon layer (300) and the perovskite layer (600).

[0084] The above substrate (100) may be a glass substrate in the case of a superstrate type structure, and may be a flexible foil made of stainless steel, PEN (polyethylene naphthalate), and polyimide in the case of a substrate type structure.

[0085] The first electrode layer (200) includes a transparent electrode (210) and a first electrode (220).

[0086] The transparent electrode (210) can be provided on the substrate (100).

[0087] The above transparent electrode (210) may be one or more of ITO (Indium Tin Oxide), ZITO (Zinc Indium Tin Oxide), ZIO (Zinc Indium Oxide) and ZTO (Zinc Tin Oxide).

[0088] The above type of transparent electrode (210) is desirable because it is easy to combine with the silicon layer (300) and has high charge carrier mobility.

[0089] The first electrode (220) can be placed between the transparent electrodes (210).

[0090] The first electrode (220) is positioned on the side of the transparent electrode (210) between the transparent electrodes (210) to effectively transfer charge carriers transferred from the transparent electrode (210), and is provided in a portion of the transparent electrode (210) so that sunlight can be incident on the rear side of the perovskite tandem solar cell (1000).

[0091] The first electrode (220) may be a metal (Ag) nanowire or a metal thin film made of one or more metals among Au, Ag, Cu, Mg, Mo and Ti.

[0092] The above type of metal can be provided on the transparent electrode (210) and can effectively transport charge carriers received from the transparent electrode (210).

[0093] The first electrode (220) can be formed as a grid having a grid pattern, and when the first electrode (220) is a grid electrode, it is easy to form a tandem solar cell module.

[0094] The silicon layer (300) is provided on the first electrode layer (200).

[0095] The silicon layer (300) may be one of the structures of a known silicon solar cell and is not limited to a specific structure. For example, the silicon layer (300) may include a crystalline silicon substrate (not shown), a p-type amorphous or crystalline silicon layer (not shown), an n-type amorphous or crystalline silicon layer (not shown), an amorphous intrinsic silicon layer (not shown), and may further include additional layers. Preferably, considering the ease of internal gettering or process simplification that helps improve cell efficiency compared to n-type silicon, the silicon layer (300) is preferably a p-type silicon layer (300).

[0096] The hole transport layer (400) is provided on the silicon layer (300).

[0097] The hole transport layer (400) can transport charge carriers transferred from the silicon layer (300).

[0098] The hole transport layer (400) may include a metal oxide layer (420) and a conductive metal layer (410).

[0099] In the inverted structure PIN, the hole transport layer (400) may include a metal oxide layer (420), for example, nickel oxide (NiO₂). x It may include ).

[0100] Specifically, the hole transport layer (400) is nickel oxide (NiOx ITO / NiO including a conductive metal layer (410) x It can be provided with a double layer of the shape.

[0101] The hole transport layer (400) above is ITO / NiO x The silicon layer (300) can be formed by various deposition methods and may include a nickel oxide layer to improve charge carrier transport capability.

[0102] The above self-assembled monolayers (SAMs; 500) are provided on the hole transport layer (400).

[0103] The self-assembled monolayer (500) comprises a carbazole compound and a mercapto compound containing a phosphonic acid anchor group, and is combined with the perovskite layer (600) and the hole transport layer (400) to maintain an interlayer structure.

[0104] The self-assembled monolayer (500) may include a carbazole compound and a mercapto compound containing a phosphonic acid anchor group.

[0105] The above carbazole compound is one or more of Me-4PACz, MeO-2PACz, and 2PACz, and the above mercapto compound may be 3-mercaptopropionic acid.

[0106] The carbazole functional group of the above carbazole compound can bond to the perovskite surface, and the phosphonic acid anchoring group can bond to the metal oxide layer.

[0107] [Chemical Formula 1]

[0108]

[0109] [Chemical Formula 2]

[0110]

[0111] [Chemical Formula 3]

[0112]

[0113] The above chemical formula 1 represents [2-(9H-Carbazol-9-yl)ethyl]phosphonic Acid (2PACz), chemical formula 2 represents [4-(3,6-Dimethyl-9H-carbazol-9-yl)butyl]phosphonic Acid (Me-4PACz), and chemical formula 3 represents [4-(7H-Dibenzo[c,g]carbazol-7-yl)butyl]phosphonic Acid (4-PADCB).

[0114] The above type of compound can be selected as a material for forming self-assembled monolayers (SAMs).

[0115] The above type of self-assembled monolayer (500) forming material includes a phosphonic acid group as an anchor group, a hydrocarbon chain as a spacer, and a carbazole group as a functional group, thereby inducing bonding between the perovskite layer (600) and the hole transport layer (400), which is a metal oxide layer (420), and can spontaneously assemble to form a very regular layer.

[0116] When the self-assembled monolayer (500) is formed, the interlayer structure between the perovskite layer (600) and the hole transport layer (400) can be stably maintained.

[0117] In one embodiment, the mercapto compound may be interposed between the carbazole compounds to reduce the spacing between the compounds. For example, 3-mercaptopropionic acid may be interposed between the carbazole compounds.

[0118] [Chemical Formula 4]

[0119]

[0120] Chemical formula 4 above represents 3-mercaptopropionic acid (3-MPA).

[0121] The 3-mercaptopropionic acid can have a hydroxyl group of its head group bonded to the metal oxide layer (420) and can react with the metal oxide layer (420) before the carbazole compound of Me-4PACz. After bonding to the metal oxide layer (420), the 3-mercaptopropionic acid, which is a relatively smaller molecule than the carbazole compound, can be substituted with the carbazole compound of Me-4PACz and arranged very densely between the carbazole compounds.

[0122] In one embodiment, the Me-4PACz and 3-MPA can be co-assembled on the surface of the metal oxide layer (420) to form a very dense molecular arrangement, and can improve charge carrier transport capability and interaction at the interface with the perovskite layer (600).

[0123] In one embodiment, in addition to the 3-mercaptopropionic acid, it is also possible for 6-(iodo-λ5-azanyl)hexanoic acid (IAHA) or phosphorylcholine chloride (PC) to combine with the metal oxide layer (420) to form a molecular arrangement.

[0124] The self-assembled monolayer (500) is formed as a monolayer and maintains a thin thickness so that it can transmit sunlight of a spectrum that is not absorbed by the perovskite layer (600) and does not affect the surface morphology of the perovskite layer (600).

[0125] The self-assembled monolayer (500) has mercapto compounds uniformly arranged between carbazole compounds, so that physical defects of the hole transport layer (400) or silicon layer (300) can also effectively prevent the perovskite layer (600) from affecting the perovskite layer (600).

[0126] In one embodiment, the self-assembled monolayer (500) may contain the mercapto compound in an amount of 0.005 mM to 1 mM. Preferably, it may contain 0.005 mM to 0.05 mM.

[0127] At this time, the self-assembled monolayer (500) contains 0.01 mM to 3 mM of a carbazole compound, and the content ratio of the mercapto compound to the carbazole compound can be adjusted to 1:0.005 to 1.

[0128] The self-assembled monolayer (500) can effectively increase the photoelectric conversion efficiency (PCE) of a perovskite tandem solar cell (1000) by including the 3-mercaptopropionic acid in the above range.

[0129] In one embodiment, the contact angle of the self-assembled monolayer (500) with respect to deionized water may be 70° to 80°.

[0130] The above self-assembled monolayer (500) may exhibit a contact angle within the above range, and in this case, the coating properties of the perovskite layer (600) may be greatly improved because the spreadability of the perovskite precursor solution dissolved in an organic solvent and applied is improved.

[0131] The above perovskite layer (600) is provided on the self-assembled monolayer (500).

[0132] The above perovskite layer (600) is provided on the self-assembled monolayer (500) and can be supported by the self-assembled monolayer (500).

[0133] The above perovskite layer (600) can be formed so that hole-electron pairs generated by receiving light energy from the sun can be separated into electrons or holes. Electrons formed in the perovskite layer (600) are transferred to the electron transport layer (800), and holes formed in the perovskite layer (600) can be transferred to the hole transport layer (400).

[0134] The perovskite layer (600) may include organic halide perovskites such as methyl ammonium iodide (MAI) and formamidinium iodide (FAI), or metal halide perovskites such as lead iodide (PbI2), bromine iodide (PbBr) and lead chloride (PbCl2), and the perovskite layer (600) may have a multilayer structure including at least one of organic or inorganic perovskites.

[0135] The above perovskite layer (600) may further include a buffer layer (700).

[0136] The above buffer layer (700) is provided between the perovskite layer (600) and the electron transport layer (800).

[0137] The above buffer layer (700) can prevent physical defects of the perovskite layer (600) from spreading, and can improve the mobility of charge carriers through the buffer layer (700) having a wide band gap.

[0138] In one embodiment, the buffer layer (700) may be LiF.

[0139] If the above buffer layer (700) is LiF, it can prevent physical defects by preventing the diffusion or decomposition of defects in the perovskite layer (600), and can also perform a buffering role by being combined with the above electron transport layer (800).

[0140] The above buffer layer (700) may be formed by a chemical vapor deposition, physical vapor deposition, vacuum deposition, or atomic layer deposition method, but is not limited thereto.

[0141] The above electron transport layer (800) is provided on the buffer layer (700).

[0142] The electron transport layer (800) above is C60 fullerene / SnO x It may include a double layer.

[0143] The electron transport layer (800) may form a double layer by including C60 fullerene as an organic compound layer (810) and a tin oxide layer (SnOx; 820) as a metal oxide layer (820).

[0144] In addition to improving electron mobility by including the above type of compound, the metal oxide (820) can be formed as a differential thin film to control electron transport.

[0145] The second electrode layer (900) is provided on the electron transport layer (800).

[0146] The second electrode layer (900) may have a metal electrode (920) arranged on a conductive metal layer (910).

[0147] The second electrode layer (900) may be provided with the same configuration as the first electrode layer (200), and a repeated description will be omitted.

[0148] In one embodiment, the front and back surfaces of the perovskite layer (600) may be textured.

[0149] The front and rear surfaces of the perovskite layer (600) can be textured to change the optical path and length of the incoming sunlight, and when the self-assembled monolayer (500) is provided, it can be bonded with the silicon layer (300) without a separate planarization process to manufacture a perovskite tandem solar cell (1000), so the manufacturing efficiency of the tandem solar cell can be greatly improved.

[0150] Accordingly, the perovskite tandem solar cell (1000) according to one embodiment of the present invention is nickel oxide (NiO) used as the hole transport layer (400) of the inverted structure PIN solar cell. xA metal oxide layer (420) is coated as a self-assembled monolayer (500), and the self-assembled monolayer (500) includes 3-mercaptopropionic acid, which is a co-assembled forming material with Me-4PACz, so that the self-assembled monolayer is arranged more densely, thereby stabilizing the interlayer structure of the perovskite layer (600) and the hole transport layer (400), and can provide a perovskite tandem solar cell (1000) with greatly improved photoelectric conversion efficiency.

[0151] Another aspect of the present invention relates to a tandem solar cell module (not shown) comprising the perovskite tandem solar cell (1000).

[0152] The above tandem solar cell module includes a perovskite tandem solar cell (1000).

[0153] The second electrode layer (900) is electrically connected to the first electrode layer (200) of an adjacent silicon perovskite solar cell.

[0154] The above tandem solar cell module includes the above perovskite tandem solar cell (1000) to improve photoelectric conversion efficiency, and the above second electrode layer (900) may be configured to be connected to the first electrode layer (200) of an adjacent solar cell by a conductive member such as a wire.

[0155] The above tandem solar cell module is easy to manufacture and can exhibit a high photoelectric conversion efficiency compared to modules made of conventional perovskite solar cells or silicon solar cells.

[0158] Hereinafter, preferred embodiments are presented to aid in understanding the present invention; however, the following embodiments are merely illustrative of the invention and the scope of the invention is not limited to the following embodiments.

[0160] Example 1

[0161] ITO / NiO on amorphous silicon solar cells xA hole transport layer was formed, and a co-assembled self-assembled monolayer was formed by mixing 3-MPA with Me-4PACz as a precursor in a ratio of 1:0.005 to 1.

[0162] A perovskite layer is formed by solution coating a self-assembled monolayer with a perovskite precursor solution dissolved in an organic solvent, and a LiF ferber layer and a C60 / SnO x A perovskite tandem solar cell was fabricated by forming an electron transport layer and arranging an Ag electrode on an ITO transparent electrode.

[0164] Example 2

[0165] A perovskite tandem solar cell was prepared in the same manner as in Example 1, except that 4-PADCB was selected as the precursor for the self-assembled monolayer.

[0167] Comparative Example 1

[0168] A perovskite tandem solar cell was prepared in the same manner as in Example 1, except that the co-assembly compound 3-MPA was not added.

[0170] Comparative Example 2

[0171] A perovskite tandem solar cell was prepared in the same manner as in Example 2, except that the co-assembly compound 3-MPA was not added.

[0173] Experimental Example 1

[0174] Value of light IV(TS) Sweep V oc [V] J sc [mA / cm 2 ] FF[%] Eff.[%] MPPT[%] Comparative Example 1 Reverse 1.773 18.64 75.74 25.04 24.45 Forward 1.756 18.62 67.91 22.21 Example 1 Reverse 1.862 18.45 79.45 27.30 26.55 Forward 1.860 18.46 70.45 24.18 Comparative Example 2 Reverse 1.855 18.52 79.05 27.15 26.35 Forward 1.847 18.53 67.81 23.20 Example 2 Reverse 1.858 18.46 80.29 27.53 26.89 Forward 1.855 18.44 71.06 24.31

[0175] Table 1 above shows the photoelectric conversion efficiency (Best) measured under AM 1.5G optical conditions using a solar simulator.

[0176] The Eff. value was measured by scanning the IV sweep for 15 seconds, and the MPPT value was measured by tracking the optimal current and voltage of the device for 5 minutes to determine the best performance per condition for each device.

[0177] Referring to Table 1 above, it was confirmed that when 3-MPA is added as a co-assembled self-assembled monolayer forming compound in Examples 1 and 2, higher solar cell charge rate (FF.) and maximum power point (MMP) are exhibited compared to when Me-4PACz or 4-PADCB is added alone.

[0178] Therefore, it was confirmed that the photoelectric conversion efficiency can be significantly improved by adding 3-MPA, which can form a more densely packed self-assembled monolayer than when Me-4PACz is assembled alone.

[0180] Experimental Example 2

[0181] 3-MPA content (mM) Value of light IV(TS, best) Sweep V oc [V] J sc [mA / cm 2 ] FF[%] Eff.[%] MPPT[%] Experimental Example 1 0.005mM Reverse 1.854 18.40 77.15 26.31 25.33 Forward 1.853 18.44 68.29 23.23 Experimental Example 2 0.025 mM Reverse 1.861 18.58 77.87 26.92 26.15 Forward 1.860 18.56 70.02 24.18 Experimental Example 3 0.05 mM Reverse 1.863 18.53 78.88 27.24 26.53 Forward 1.862 18.54 70.85 24.45 Experimental Example 4 0.5 mM Reverse 1.834 17.76 77.53 25.24 24.82 Forward 1.832 17.77 73.90 24.06 Experimental Example 5 1 mM Reverse 1.795 17.56 75.22 23.71 23.18 Forward 1.794 17.57 71.84 22.65

[0182] Table 2 above shows the photoelectric conversion efficiency according to the amount of 3-MPA added.

[0183] Referring to Table 2, it was confirmed that the photoelectric conversion efficiency increased as the amount of 3-MPA added increased, and in particular, at 0.05 mM, a maximum photoelectric conversion efficiency of 27.24% was observed, confirming that it can exhibit superior photoelectric conversion efficiency compared to the photoelectric conversion efficiency of conventional tandem solar cells.

[0184] When added at a concentration of 0.05 mM or higher, the photoelectric conversion efficiency tended to decrease, confirming the increase or decrease in photoelectric conversion efficiency according to the amount added.

[0186] Experimental Example 3

[0187] FIG. 4 shows the contact angle measurement results for deionized water of a self-assembled monolayer in a perovskite tandem solar cell according to one embodiment of the present invention.

[0188] Referring to FIG. 4, when examining the contact angles according to Comparative Example 1 (Me-4PACz alone coating) in (a), Example 1 (Me-4PACz + 3-MPA mixed coating) in (b), Comparative Example 2 (4-PADCB alone coating) in (c), and Example 2 (4-PADCB + 3-MPA mixed coating) in (d), it was confirmed that the contact angle changed depending on the type of NiOx coated SAMs material, and that the contact angle increased significantly when the Me-4PACz and 3-MPA mixed coating was applied in Example 1 compared to the Me-4PACz alone coating in Comparative Example 1. This indicates that contact with organic solvents is improved, and it was confirmed that the coating properties of the perovskite layer are greatly enhanced by improving the spreadability of the perovskite solution dissolved in organic solvents.

[0189] Accordingly, the perovskite tandem solar cell according to the present invention is nickel oxide (NiO₂) selected as a hole transport layer in an inverted structure PIN solar cell. x By stabilizing ) into a self-assembled monolayer, a perovskite layer can be formed very effectively, and various types of perovskite tandem solar cells with curves or patterns can be provided.

[0191] The present invention has been described above with reference to embodiments. Those skilled in the art will understand that the present invention may be embodied in modified forms without departing from the essential characteristics of the invention. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the invention is defined by the claims, not by the foregoing description, and all variations within the scope of equivalents should be interpreted as being included in the invention. Explanation of the symbols

[0193] 1000 : Perovskite tandem solar cell 100 : Substrate 200 : First electrode layer 210: Transparent electrode 220: First electrode 300: Silicon layer 400: Hole transport layer 410: Conductive metal layer 420: Metal oxide layer 500: Self-assembled monolayer 600: Perovskite layer 700: Buffer layer 800: Electron transport layer 810: Organic compound layer 820: Metal oxide layer 900: Second electrode layer 910: Conductive metal layer 920 : Metal electrode

Claims

Claim 1 A perovskite solar cell comprising: a metal oxide layer; a self-assembled monolayer formed on the metal oxide layer; and a perovskite layer formed on the self-assembled monolayer; wherein the self-assembled monolayer comprises a carbazole compound containing a phosphonic acid anchor group and a mercapto compound, and the hydroxyl group of the head group of the mercapto compound is bonded to the metal oxide layer, so that the carbazole compound and the mercapto compound are co-assembled on the surface of the metal oxide layer to form a molecular arrangement. Claim 2 A perovskite solar cell according to claim 1, further comprising a conductive metal layer below the metal oxide layer. Claim 3 A perovskite solar cell according to claim 1, wherein the molar ratio of (a) a carbazole compound containing a phosphonic acid anchor group and (b) a mercapto compound is (a) : (b) = 1 : 0.005 to 1. Claim 4 A perovskite solar cell according to claim 1, wherein the carbazole compound is one or more of Me-4PACz, MeO-2PACz, and 2PACz, and the mercapto compound is 3-mercaptopropionic acid. Claim 5 A perovskite solar cell according to claim 1, wherein the carbazole functional group of the carbazole compound is bonded to the perovskite film and the phosphonic acid anchor group is bonded to the metal oxide layer. Claim 6 A perovskite tandem solar cell comprising: a substrate; a first electrode layer disposed on the substrate; a silicon layer disposed on the first electrode layer; a hole transport layer disposed on the silicon layer; a self-assembled monolayer (SAM) disposed on the hole transport layer; a perovskite layer disposed on the self-assembled monolayer; an electron transport layer disposed on the perovskite layer; and a second electrode layer disposed on the electron transport layer; wherein the self-assembled monolayer comprises a carbazole compound and a mercapto compound containing a phosphonic acid anchor group, and the interlayer structure is maintained by bonding with the perovskite layer and the hole transport layer, and the hydroxyl group of the head group of the mercapto compound is bonded to the metal oxide layer of the hole transport layer, so that the carbazole compound and the mercapto compound are co-assembled on the surface of the metal oxide layer to form a molecular arrangement. Claim 7 A perovskite tandem solar cell according to claim 6, wherein the first electrode layer comprises a transparent electrode and a first electrode. Claim 8 A perovskite tandem solar cell according to claim 6, further comprising a buffer layer containing LiF between the perovskite layer and the electron transport layer. Claim 9 A perovskite tandem solar cell according to claim 6, wherein the carbazole compound is one or more of Me-4PACz, MeO-2PACz, and 2PACz, and the mercapto compound is 3-mercaptopropionic acid. Claim 10 A perovskite tandem solar cell according to claim 9, wherein the carbazole functional group of the carbazole compound is bonded to the perovskite layer and the phosphonic acid anchoring group is bonded to the metal oxide. Claim 11 A perovskite tandem solar cell according to claim 10, wherein the mercapto compound is interposed between carbazole compounds to reduce the arrangement spacing between compounds. Claim 12 A perovskite tandem solar cell according to claim 6, wherein the self-assembled monolayer comprises the mercapto compound in an amount of 0.005 mM to 1 mM. Claim 13 A perovskite tandem solar cell according to claim 6, wherein the contact angle of the self-assembled monolayer with respect to deionized water is 70° to 80°. Claim 14 A perovskite tandem solar cell according to claim 6, wherein the hole transport layer comprises a metal oxide layer and a conductive metal layer. Claim 15 A perovskite tandem solar cell according to claim 14, wherein the metal oxide layer comprises NiOx. Claim 16 A perovskite tandem solar cell according to claim 6, wherein the electron transport layer comprises a C60 fullerene / SnOx bilayer. Claim 17 A perovskite tandem solar cell according to claim 6, wherein the second electrode layer is a conductive metal layer in which a metal electrode is arranged. Claim 18 A perovskite tandem solar cell according to claim 6, wherein the front and back surfaces of the perovskite layer are textured. Claim 19 A tandem solar cell module comprising a perovskite tandem solar cell according to any one of claims 6 to 18, wherein the second electrode layer is electrically connected to the first electrode layer of an adjacent perovskite tandem solar cell.

Images