Quasi-two-dimensional perovskite film and preparation method thereof, perovskite photoactive layer and triple-junction stacked battery

Abstract

The present application relates to the technical field of solar cells, and in particular to a quasi-two-dimensional perovskite film and a preparation method thereof, a perovskite photoactive layer and a triple-junction stacked cell. The preparation method of the quasi-two-dimensional perovskite film comprises: obtaining the corresponding raw materials according to the general formula of the quasi-two-dimensional perovskite material; mixing the raw materials, organic additives and solvents to obtain a precursor solution; using the precursor solution to form a film, drying and annealing to obtain a quasi-two-dimensional perovskite film; the present application adopts organic additives to make the prepared quasi-two-dimensional perovskite film have a higher phase purity, the amount of inorganic octahedron layers in the quasi-two-dimensional perovskite film is less than or equal to 3, and the amount of three-dimensional phase formation is increased, which is beneficial to the transmission of carriers, and the quasi-two-dimensional perovskite film is more suitable for use as a perovskite photoactive layer.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a quasi-two-dimensional perovskite film and a preparation method thereof, a perovskite photoactive layer and a triple-junction stacked cell. Background Art

[0002] In order to break through the theoretical limits of solar cells, stacked solar cell technology was proposed and has been developed to a certain extent. The limits of triple-junction cells with a concentrating system have set a new world record. The triple-junction cell is mainly made of semiconductor materials such as gallium arsenide, gallium indium phosphide and germanium. Due to the abundance restrictions of these elements, the complex preparation process and the need for a concentrating system, the cost of preparing this type of triple-junction cell is high, making it difficult to achieve large-scale commercial applications.

[0003] In comparison, the cost advantages of perovskite materials and preparation processes make them have great application prospects. Some key issues that limit the efficiency improvement of perovskite triple-junction cells still need to be overcome, such as phase separation in perovskites, narrow bandgap regulation range of perovskites, and stability of perovskite layers. Therefore, solving the above problems is crucial to the development of efficient and stable triple-junction stacked solar cells.

[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the invention

[0005] The embodiments of the present application provide a quasi-two-dimensional perovskite film and a preparation method thereof, a perovskite photoactive layer and a triple-junction stacked cell to solve or alleviate one or more of the technical problems raised above.

[0006] A first aspect of an embodiment of the present application provides a method for preparing a quasi-two-dimensional perovskite film.

[0007] The method for preparing the quasi-two-dimensional perovskite film comprises the following operations: According to the general formula of quasi-two-dimensional perovskite materials, corresponding raw materials are obtained; Mixing the raw materials, organic additives and solvent to obtain a precursor solution; Forming a film using the precursor solution, and annealing after drying to obtain a quasi-two-dimensional perovskite film; Wherein, the structural formula of the organic additive is shown in Formula I:

[0008] In Formula I, R1 is selected from -S- or -O-; R2, R3, R4, and R5 are independently selected from -(CH2) n1 COOH, -(CH2) n2 CH(COOH)2, -(CH2) n3C(COOH)3, -H, -OH, -(CH2) n4 CH3, and at least one of R2, R3, R4, and R5 is -(CH2) n1 COOH, -(CH2) n2 CH(COOH)2 or -(CH2) n3 C(COOH)3; n1, n2, n3, and n4 are each independently selected from integers between 0 and 6.

[0009] In the first aspect of the embodiments of the present application, the above-mentioned organic additives are used. In the precursor solution, the five-membered ring of the organic additive is used to adjust the micelle state of the precursor solution, thereby affecting the crystal nucleus, so that the prepared quasi-two-dimensional perovskite film has a higher phase purity, the amount of phase formation in which the number of layers of inorganic octahedrons in the quasi-two-dimensional perovskite film is less than or equal to 3, and the amount of three-dimensional phase formation is increased, which is beneficial to the transmission of carriers. The quasi-two-dimensional perovskite film is more suitable for application as a perovskite photoactive layer.

[0010] A second aspect of an embodiment of the present application provides a quasi-two-dimensional perovskite film prepared in the first aspect.

[0011] The quasi-two-dimensional perovskite film of the second aspect of the embodiment of the present application has a higher phase purity, the amount of phase formed in which the number of layers of inorganic octahedrons in the quasi-two-dimensional perovskite film is less than or equal to 5 is less, and the amount of three-dimensional phase formed is increased. The quasi-two-dimensional perovskite film is more suitable for use as a perovskite photoactive layer.

[0012] The third aspect of the embodiment of the present application provides a perovskite photoactive layer, which includes the quasi-two-dimensional perovskite film described in the second aspect. As a result, the photovoltaic properties of the quasi-two-dimensional perovskite film are improved, the carrier transmission capacity is greatly improved, and it can be used as a perovskite photoactive layer.

[0013] The fourth aspect of the embodiment of the present application provides a triple-junction stacked cell, which includes a sub-cell, and the sub-cell includes the perovskite photoactive layer described in the third aspect. Thus, it has better light stability and can improve the conversion efficiency of the triple-junction cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0015] Figure 1 It is a flow chart provided by an embodiment of the present application; Figure 2 It is a schematic diagram of the structure of a triple-junction stacked battery provided in an embodiment of the present application; Figure 3 It is a fluorescence spectrum diagram of the quasi-two-dimensional perovskite film of Examples 1 to 3 of the present application and Comparative Example 1; Figure 4 It is the IV curve of the triple-junction stacked battery of Examples 5-6 and Comparative Examples 2-3 of the present application; Figure 5 It is a curve showing the change of conversion efficiency over time of the triple-junction stacked cells of Examples 5 to 6 of the present application and Comparative Example 3.

[0016] Description of reference numerals: 1-first electrode; 2-first electron transport layer; 3-first perovskite photoactive layer; 4-first hole transport layer; 5-first tunneling layer; 6-second electron transport layer; 7-second perovskite photoactive layer; 8-second hole transport layer; 9-second tunneling layer; 10-third electron transport layer; 11-third photoactive layer; 12-third hole transport layer; 13-second electrode. DETAILED DESCRIPTION

[0017] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. In the accompanying drawings, for clarity, the sizes of layers, regions, elements and their relative sizes may be exaggerated. Wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limitations on the present application. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0018] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. When the second element, component, region, layer or part is discussed, it does not indicate that the present application necessarily has the first element, component, region, layer or part.

[0019] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0020] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0021] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to an integer in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed in the present application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for broadly including quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0022] Currently, the inhibition of iodide ions (I - ) and bromide ion (Br - ) phase separation techniques include introducing some substitutes, such as chloride ions (Cl - ), thiocyanate ion (SCN - ), etc., the introduction of the above monovalent cation substitutes can also inhibit I - and Br - Partial substitution of bromide ions can suppress phase separation in perovskites with a band gap below 1.8 eV to a certain extent, but for perovskites with a wider band gap than those with a higher bromine content, partial substitution of bromine is difficult to overcome this problem, and the long-term stability of perovskite components with a high bromine content is poor.

[0023] Based on this, the embodiments of the present application provide a quasi-two-dimensional perovskite film and a preparation method thereof, a perovskite photoactive layer and a triple-junction stacked cell. See below for details.

[0024] Hereinafter, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. It should be noted that these exemplary embodiments can be implemented in many different forms and should not be construed as being limited to the embodiments described herein.

[0025] A first aspect of an embodiment of the present application provides a method for preparing a quasi-two-dimensional perovskite film.

[0026] In some embodiments, see Figure 1 The method for preparing the quasi-two-dimensional perovskite film comprises the following operations: S1. Obtaining corresponding raw materials according to the general formula of quasi-two-dimensional perovskite materials; S2, mixing the raw materials, organic additives and solvent to obtain a precursor solution; S3, forming a film using the precursor solution, and annealing after drying to obtain a quasi-two-dimensional perovskite film; Wherein, the structural formula of the organic additive is shown in Formula I:

[0027] In Formula I, R1 is selected from -S- or -O-; R2, R3, R4, and R5 are independently selected from -(CH2) n1 COOH, -(CH2) n2 CH(COOH)2, -(CH2) n3 C(COOH)3, -H, -OH, -(CH2) n4 CH3, and at least one of R2, R3, R4, and R5 is -(CH2) n1 COOH, -(CH2) n2 CH(COOH)2 or -(CH2) n3 C(COOH)3; n1, n2, n3, n4 are each independently selected from integers between 0 and 6.

[0028] In the embodiment of the present application, the above organic additives are used. In the precursor solution, the five-membered ring of the organic additive is used to adjust the micelle state of the precursor solution, thereby affecting the crystal nucleus, so that the prepared quasi-two-dimensional perovskite film has a higher phase purity, and the amount of inorganic octahedron layers less than or equal to 3 in the quasi-two-dimensional perovskite film is less, and the amount of three-dimensional phase formation is increased, which is conducive to the transmission of carriers. The quasi-two-dimensional perovskite film is more suitable for use as a perovskite photoactive layer. Optionally, R2 is -H or -COOH; R3 is -H, -CH(COOH)2 or -CH2COOH; R4 is -H; R5 is -H.

[0029] Exemplarily, the organic additive includes: (3-thiopheneacetic acid), (2-thiophenecarboxylic acid), (3-Thienylmalonic acid), (2-furancarboxylic acid), (3-furancarboxylic acid).

[0030] In S1 of the embodiment of the present application, the phase structure of the quasi-two-dimensional perovskite film may include a Ruddlesden-Popper (RP) phase structure and a Dion-Jacobson (DJ) phase structure.

[0031] Furthermore, the general formula of the RP phase structure is A'2A n-1 B n X 3n+1, wherein A' is a monovalent organic ammonium cation, and n represents [BX6] 4+ The number of layers, n is a positive integer greater than or equal to 1, for example, n is 1 to 6; A' is between different layered structures, and the band gap of the RP phase structure can be adjusted by adjusting the type of A' and the size of the n value.

[0032] For example, A' can be selected from one of the following groups: , , , , , , , , , , , , , , , .

[0033] Furthermore, the general formula of the DJ phase structure is A''A n-1 B n X 3n+1 , A'' is a divalent organic ammonium cation, n represents [BX6] 4+ The number of layers, n is a positive integer greater than or equal to 1, for example, n is 1-6.

[0034] For example, A'' can be selected from one of the following groups: , , , , , , , , , , , , , , .

[0035] In the embodiments of the present application, the raw materials for preparing the quasi-two-dimensional perovskite film are not limited. Those skilled in the art can select the corresponding raw materials according to the quasi-two-dimensional perovskite film of the RP phase and the quasi-two-dimensional perovskite film of the DJ phase structure. As some examples, the raw materials may include A 、 , AX and BX2; among them, A 、 Including monoamine compounds or diamine compounds; A includes methylamine cation, formamidine cation, K+ , Rb + , Cs + At least one of; B includes Pb 2+ ,Ge 2 + Sn 2+ , Cu 2+ 、Ni 2+ 、Co 2+ , Fe 2+ , Mn 2+ 、Eu 2+ At least one of; X includes Cl - Br - ,I - The organic additive acts as an electron-rich Lewis base and can eliminate the uncoordinated Pb in the quasi-two-dimensional perovskite film. 2+ , thereby reducing the defect density.

[0036] In S2 of the embodiment of the present application, the solvent includes N,N-dimethylformamide (DMF) and / or dimethyl sulfoxide (DMSO). For example, a mixed liquid of DMF and DMSO in a volume ratio of 4:1 is used as the solvent.

[0037] In S3 of the embodiment of the present application, the film formation using the precursor solution, drying and annealing to obtain a quasi-two-dimensional perovskite film may include the following operations: film formation using a spin coating method, followed by drying in a vacuum environment, and then annealing at 100°C to 150°C for 5min to 10min to obtain a quasi-two-dimensional perovskite film. Thus, drying in a vacuum environment allows the DMF with a low boiling point to evaporate first, thereby facilitating the rapid formation of crystal nuclei; and DMSO reacts with [BX6] in the solution. 4+ The intermediate phase DMSO-PbI2 formed by coordination, the existence of vacuum drying makes the transformation rate of this intermediate phase slower than the transformation rate of direct thermal annealing, which is beneficial to prolong the growth time of the crystal. The above changes are all conducive to the growth of three-dimensional phases with higher crystallinity.

[0038] Optionally, the vacuum degree of the vacuum environment is 10 -6 mbar~100 mbar.

[0039] Optionally, when the film is formed by spin coating, the substrate may be a high-temperature substrate, for example, a substrate at 40°C to 100°C. Thus, the use of a high-temperature substrate can allow the crystal nuclei of the quasi-two-dimensional perovskite film to be formed mainly on the lower interface (on the substrate) by heterogeneous nucleation during the preparation process, so that the crystal growth process is carried out from bottom to top, which is conducive to the vertical growth of the crystal on the substrate.

[0040] The second aspect of the embodiment of the present application provides a quasi-two-dimensional perovskite film, which is prepared according to the preparation method described in the first aspect. As a result, the phase purity of the quasi-two-dimensional perovskite film is higher, the amount of phase formation with the number of layers of inorganic octahedrons less than or equal to 3 in the quasi-two-dimensional perovskite film is less, and even the amount of phase formation with the number of layers of inorganic octahedrons of 4 and 5 in the quasi-two-dimensional perovskite film is less, and the amount of three-dimensional phase formation increases, and the quasi-two-dimensional perovskite film is more suitable for use as a perovskite photoactive layer.

[0041] Furthermore, the band gap of the quasi-two-dimensional perovskite film can be regulated by regulating the number of layers of monovalent organic ammonium cations and inorganic octahedrons in the quasi-two-dimensional perovskite film, or the band gap of the quasi-two-dimensional perovskite film can be regulated by regulating the number of layers of divalent organic ammonium cations and inorganic octahedrons in the quasi-two-dimensional perovskite film. The band gap of the quasi-two-dimensional perovskite film is adjustable, and the adjustable band gap range is 1.60 eV to 3.0 eV.

[0042] At present, there are problems with the purity of the two-dimensional phase and the crystallinity of the three-dimensional phase in quasi-two-dimensional films, which makes it impossible to effectively extract carriers from the inside of the perovskite layer, resulting in poor device performance; quasi-two-dimensional films have many internal defects in the crystal, resulting in serious non-radiative recombination of carriers during transmission. The quasi-two-dimensional film of the present application improves the content of the three-dimensional phase and the crystal quality, effectively reduces the non-radiative recombination of carriers, and thus has better optoelectronic properties. Compared with three-dimensional perovskites, the quasi-two-dimensional perovskite film used in the present application can increase the adjustable range of the band gap. At the same time, due to the presence of the two-dimensional phase, the migration of the Br element and the I element under light can be prevented, making the I element / Br element more stable and reducing the phase separation caused by light.

[0043] Accordingly, the third aspect of the embodiment of the present application provides a perovskite photoactive layer, including the quasi-two-dimensional perovskite film described in the second aspect. As a result, the photovoltaic properties of the quasi-two-dimensional perovskite film are improved, the carrier transmission capacity is greatly improved, and it can be used as a perovskite photoactive layer.

[0044] The perovskite photoactive layer of the third aspect can be applied to single-junction cells and multi-junction cells, and is particularly suitable for triple-junction cells. Accordingly, the fourth aspect of the embodiment of the present application provides a triple-junction stacked cell, including a sub-cell, wherein the sub-cell includes the perovskite photoactive layer described in the third aspect. Thus, it has better light stability and can improve the conversion efficiency of the triple-junction cell.

[0045] For some examples, see Figure 2, a triple junction stacked cell can be formed by stacking pin-type sub-cells (or pin-type sub-cells) with tunneling layers between the sub-cells. When all the sub-cells are pin-type cells, the triple-junction stacked cell includes a first electrode 1, a first sub-cell (a first electron transport layer 2, a first perovskite photoactive layer 3 and a first hole transport layer 4 stacked in sequence), a first tunneling layer 5, a second sub-cell (a second electron transport layer 6, a second perovskite photoactive layer 7 and a second hole transport layer 8 stacked in sequence), a second tunneling layer 9, a third sub-cell (a third electron transport layer 10, a third photoactive layer 11, a third hole transport layer 12 stacked in sequence) and a second electrode 13 stacked in sequence from top to bottom; wherein the first perovskite photoactive layer 3 is a quasi-two-dimensional perovskite film of the second aspect of the present application, with a band gap of 1.60 eV to 3.0 eV; the second perovskite photoactive layer 7 is a perovskite material with a band gap of 1.2 eV to 1.60 eV; the third photoactive layer 11 has a band gap of 0.9 eV to 1.2 eV, and can be made of silicon, a III-V semiconductor material, a II-VI semiconductor material and a perovskite material.

[0046] Optionally, the first electrode 1 and the second electrode 13 may be made of at least one of a transparent conductive oxide, a conductive polymer, and a metal electrode.

[0047] Optionally, the first electron transport layer 2, the second electron transport layer 6 and the third electron transport layer 10 may be made of at least one of sucrose olefins and their derivatives, n-type metal oxides, n-type organic small molecules and n-type organic small molecule polymers.

[0048] Optionally, the first hole transport layer 4 , the second hole transport layer 8 , and the third hole transport layer 12 may be made of at least one of p-type metal oxides, p-type self-assembled monomolecules, p-type organic small molecules, and p-type organic polymers.

[0049] Optionally, the first tunneling layer 5 and the second tunneling layer 9 may be made of transparent conductive oxide.

[0050] The following will conduct performance tests on the quasi-two-dimensional perovskite film, the structure or manufacturing method of the triple-junction stacked battery provided in the embodiments of the present application, and related comparative examples.

[0051] [Example 1] The specific preparation process of quasi-two-dimensional perovskite film is as follows: Step 1: According to the general formula of quasi-two-dimensional perovskite materials (TAM) 2FA4Pb5I 16 , obtain the corresponding raw materials, specifically, by mass, obtain 188.0 parts of , 687.9 parts of FAI, 2305 parts of PbI2, 27.0 parts of MACl and 111.3 parts of PbCl2; Take 33.2 parts of 3-thiopheneacetic acid as an organic additive; Step 2: Add the above raw materials and organic additives to a mixed solution of DMF and DMSO (volume ratio of 4:1) to obtain a precursor solution with micelles, and stir at 50° C. for 12 h; Step 3: Heat the quartz glass to 100°C, drop the precursor solution onto the quartz glass, rotate it at 3000 rpm for 40 seconds, then put it into a vacuum chamber and evacuate it to 0.1 mbar for 2 minutes, then take it out and place it on a hot plate at 120°C and heat it for 8 minutes to obtain a quasi-two-dimensional perovskite film with a band gap of 1.85 eV.

[0052] [Example 2] Step 1: According to the general formula of quasi-two-dimensional perovskite materials (TAM) 2FA4Pb5I 16 , obtain the corresponding raw materials, specifically, by mass, obtain 188.0 parts of , 687.9 parts of FAI, 2305 parts of PbI2, 27.0 parts of MACl and 111.3 parts of PbCl2; 33.2 parts of 3-thienylmalonic acid were taken as an organic additive; Step 2: Add the above raw materials and organic additives to a mixed solution of DMF and DMSO (volume ratio of 4:1) to obtain a precursor solution with micelles, and stir at 50° C. for 12 h; Step 3: Heat the quartz glass to 100°C, drop the precursor solution onto the quartz glass, rotate it at 3000 rpm for 40 seconds, then take it out and place it on a hot plate at 120°C and heat it for 8 minutes to obtain a quasi-two-dimensional perovskite film with a band gap of 1.85 eV.

[0053] [Example 3] Step 1: According to the general formula of quasi-two-dimensional perovskite materials PDAFA4Pb5I 16 , obtain the corresponding raw materials, and obtain 72.6 parts by mass. , 756.7 parts of FAI, 2535.5 parts of PbI2, 27.0 parts of MACl and 111.3 parts of PbCl2; Take 33.2 parts of 3-furancarboxylic acid as an organic additive; Step 2: Add the above raw materials and organic additives to a mixed solution of DMF and DMSO (volume ratio of 4:1) to obtain a precursor solution with micelles, and stir at 50° C. for 12 h; Step 3: Heat the quartz glass to 100°C, drop the precursor solution onto the quartz glass, rotate it at 3000 rpm for 40 seconds, then put it into a vacuum chamber and evacuate it to 0.1 mbar for 2 minutes, then take it out and place it on a hot plate at 120°C and heat it for 8 minutes to obtain a quasi-two-dimensional perovskite film with a band gap of 1.87 eV.

[0054] [Example 4] according to Figure 2 The pin-type triple-junction stacked battery is prepared as shown, and the specific preparation method is as follows: Step 1: providing a 300 micron thick silicon wafer, on which the pyramid thickness is about 1 micron, and then using plasma enhanced chemical vapor deposition (PECVD) to prepare a layer of doped amorphous silicon on the upper and lower surfaces of the silicon wafer, with a thickness of about 5 nm, as the third photoactive layer 11; Step 2: Prepare 8 nm thick n-type microcrystalline silicon on the upper surface of the third photoactive layer 11 by PECVD as the third electron transport layer 10; prepare 20 nm p-type microcrystalline silicon on the lower surface of the third photoactive layer 11 by PECVD as the third hole transport layer 12; prepare a 70 nm IZO layer on the third hole transport layer 12 by magnetron sputtering, and then prepare a 500 nm silver layer on the IZO by vacuum evaporation as the second electrode 13; Step 3: magnetron sputtering is performed on the third electron transport layer 10, using a target material of indium oxide and zinc oxide with a molar ratio of 90:10, argon and oxygen as sputtering gases, and a vacuum degree of 10 -5 Torr, with a sputtering power of 300 W, a 30 nm thick IZO film was deposited to obtain a second tunneling layer 9; Step 4: Prepare a second hole transport layer 8 on the second tunneling layer 9. Dissolve the self-assembled monomolecule [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid (Me-4PACz) in an ethanol solution to prepare a 0.5 mg / mL Me-4PACz solution. Spin-coat the Me-4PACz solution on the second tunneling layer 9 at 3000 rpm for 30 seconds, and then anneal at 100° C. for 10 minutes to obtain a second hole transport layer 8 with a thickness of 2 nm. Step 5: Prepare the second perovskite photoactive layer 7 on the second hole transport layer 8 according to Cs 0.1 MA 0.1 FA 0.8 Pb(I 0.98 Br 0.02)3, weigh CsI, MAI, FAI, PbI2, PbBr2, use N,N'-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) with a volume ratio of 4:1 as solvent, prepare a 1.75 mol / L precursor solution, and stir at room temperature for 6 hours; spin-coat the precursor solution on the second hole transport layer 8, spin-coat at a speed of 2000 rpm for 20s and at a speed of 5000 rpm for 30s; then place it on a 100 °C hot stage for annealing for 10 minutes to obtain a second perovskite photoactive layer 7 with a thickness of 800nm; Step 6: Prepare the second electron transport layer 6 on the second perovskite photoactive layer 7 by vacuum evaporation. -5 15nm of ethylene (C 60 ) to the second perovskite photoactive layer 7; and then the C 60 A 20 nm layer of tin oxide (SnO x ), that is, the second electron transport layer 6 is obtained; Step 7: Prepare the first tunneling layer 5 on the second electron transport layer 6, perform magnetron sputtering on the second electron transport layer 6, use a target material of indium oxide and zinc oxide with a molar ratio of 90:10, use argon and oxygen as sputtering gases, and vacuum 10 -5 Torr at a sputtering power of 300 W to deposit a 30 nm thick IZO film to obtain a first tunneling layer 5; Step 8: Prepare a first hole transport layer 4 on the first tunneling layer 5, dissolve self-assembled monomolecule [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid (Me-4PACz) in an ethanol solution to prepare a 0.5 mg / mL Me-4PACz solution; spin-coat the Me-4PACz solution on the first tunneling layer 5 at 3000 rpm for 30 seconds, and then thermally anneal at 100° C. for 10 minutes to obtain a 2 nm first hole transport layer 4; Step nine, preparing the first perovskite photoactive layer 3 with the first hole transport layer 4 as the substrate, the preparation method is the same as that in Example 1; Step 10: Prepare the first electron transport layer 2 on the first perovskite photoactive layer 3 by vacuum evaporation. -5 15nm of ethylene (C 60 ) to the second perovskite photoactive layer 7; and then atomic layer deposition is used on C 60 A 20 nm layer of tin oxide (SnO x ), that is, the first electron transport layer 2 is obtained; Step 11: First Electron Transport Layer 2 Prepare the first electrode 1 by vacuum evaporation to prepare a 300 nm silver film; then use indium oxide / zinc oxide (90 / 10 molar ratio) as a target, argon and oxygen as sputtering gases, and vacuum 10 - 5 Under 300 Torr, sputtering was performed at 300 W to deposit a 50 nm IZO thin film to obtain the first electrode 1.

[0055] [Example 5] The rest is the same as Example 4, except that in step nine, the first hole transport layer 4 is used as a substrate to prepare the first perovskite photoactive layer 3, and the preparation method is the same as Example 2.

[0056] [Example 6] The rest is the same as Example 4, except that in step nine, the first hole transport layer 4 is used as a substrate to prepare the first perovskite photoactive layer 3, and the preparation method is the same as Example 3.

[0057] [Comparative Example 1] The other operations are the same as those in Example 1, except that: no organic additive is added in step 1; and there is no vacuum treatment in step 3. Specifically, Step 1: According to the general formula of quasi-two-dimensional perovskite materials (TAM) 2FA4Pb5I 16 , obtain the corresponding raw materials, and obtain 188.0 parts by mass. , 687.9 parts of FAI, 2305 parts of PbI2, 27.0 parts of MACl and 111.3 parts of PbCl2; Step 2, adding the above raw materials and organic additives to a mixed solution of DMF / DMSO (4 / 1) to obtain a precursor solution, and stirring at 50° C. for 12 h; Step 3: Heat the quartz glass to 100°C, drop the precursor solution onto the quartz glass, rotate it at 3000 rpm for 40 seconds, then take it out and place it on a hot plate at 120°C and heat it for 8 minutes to obtain a quasi-two-dimensional perovskite film.

[0058] [Comparative Example 2] The rest is the same as Example 4, except that in step nine, the first hole transport layer 4 is used as a substrate to prepare the first perovskite photoactive layer 3, and the preparation method is the same as that of Comparative Example 1.

[0059] [Comparative Example 3] The other parts are the same as those in Example 4, except that in step nine, the first hole transport layer 4 is used as a substrate to prepare the first perovskite photoactive layer 3, the first perovskite photoactive layer 3 adopts a three-dimensional perovskite film, and the preparation method of the three-dimensional perovskite film is: According to Cs 20 FA70 MA 10 Pb(I 40 Br 60 )3, obtain the corresponding raw materials, specifically, by weight, add 88.3 parts of CsI, 27.0 parts of MAI, 116.9 parts of FAI, 567.4 parts of PbI2, and 190.9 parts of PbBr2 into a mixed solvent of N,N'-dimethylformamide (DMF) / dimethyl sulfoxide (DMSO) (4 / 1) to prepare a 1.0 mol / L precursor solution, and stir at room temperature for 6 hours; The precursor solution was spin-coated on the first hole transport layer 4, rotated at 1000 rpm for 10 seconds and then at 4000 rpm for 40 seconds, and then placed on a 100° C. hot stage for annealing for 10 minutes to obtain a 300 nm 1.95 eV perovskite photoactive layer.

[0060]

Test example

[0061] join Figure 3 , Figure 3 is the fluorescence spectrum of Examples 1 to 3 and Comparative Example 1, from Figure 1 It can be seen that the intensity of the two-dimensional phase in Examples 1 to 3 is significantly reduced compared with that in Comparative Example 1, indicating that the formation of the two-dimensional phase in Examples 1 to 3 has been suppressed, and the relative content of the two-dimensional phase has also been controlled to a certain extent, which is specifically reflected in that compared with Comparative Example 1, the fluorescence intensity at n equals 1 to 3 in Examples 1 to 3 is greatly weakened, and even the fluorescence intensity at n equals 4 and 5 in Example 1 has been reduced. In addition, the emission peak intensity of the quasi-three-dimensional phase formed in Examples 1 to 3 is significantly enhanced, and the above changes are all conducive to the transmission of carriers. At the same time, the emission peak intensity of the quasi-two-dimensional perovskite films of Examples 1 to 3 at around 680nm has been improved to varying degrees. This is due to the passivation effect of the two-dimensional phase structure, which reduces the defect density of the three-dimensional phase in the system of Examples 1 to 3.

[0062] 2. The triple junction stacked cells of Examples 4 to 6 and the triple junction stacked cells of Comparative Examples 2 to 3 were subjected to IV tests. The IV test conditions were as follows: under the standard spectrum of AM1.5G, the stacked cells were scanned from 3.5V to -0.1V, the step length was 0.05V, the dwell time was 20ms, and the results were shown in Table 2. Figure 4 and Table 1.

[0063] from Figure 4As can be seen from Table 1, the performance of the three-junction stacked battery of Examples 4 to 6 is compared with that of the three-junction stacked battery of Comparative Example 2. The open circuit voltage, short circuit current density, fill factor and conversion efficiency of the three-junction stacked battery of Examples 4 to 6 are greatly improved. The performance of the three-junction stacked battery of Examples 4 to 6 is at the same level as that of Comparative Example 3, or even better than that of Comparative Example 3. Specifically, the open circuit voltage and fill factor of Examples 4 and 5 are better than those of Comparative Example 3, which is mainly due to the lower crystal defects in the perovskite photoactive film in Examples 4 and 5. The device performance of Comparative Example 2 is poor, which is due to the large disorder of the two-dimensional phase structure used in the perovskite photoactive layer in Comparative Example 2, and the ratio of the two-dimensional phase to the three-dimensional phase is relatively high. At the same time, due to the relatively large carrier binding energy in the two-dimensional phase structure, it is difficult for the excitons to dissociate into free electrons, thereby hindering the movement of carriers, resulting in poor performance of the three-junction stacked battery. The ratio of the two-dimensional / three-dimensional phase in the perovskite photoactive layer in Examples 4 to 6 becomes smaller, so the two-dimensional phase has little effect on carrier transport. At the same time, due to the reduction of defects in the perovskite photoactive layer, the photoelectric performance of the device is further improved.

[0064] 3. The stability test was conducted on the triple-junction stacked cells of Examples 4 to 6 and the triple-junction stacked cells of Comparative Example 3. The stability test conditions were as follows: the triple-junction stacked cells were placed under open circuit voltage and continuously illuminated under the standard spectrum of AM1.5G, and then IV data were collected at intervals to obtain a graph showing the relationship between conversion efficiency and time. The results are shown in FIG. Figure 5 .

[0065] from Figure 5 It can be seen that the decay rates of the conversion efficiencies of Examples 4, 5, and 6 within 7 days are all lower than that of Comparative Example 3, which indicates that the stability of Examples 4, 5, and 6 is improved compared to that of Comparative Example 3. This is due to the presence of the two-dimensional phase, which can prevent the migration of the Br element / I element under light, making the I element / Br element more stable, reducing the phase separation caused by light, and thus improving the stability of the device.

[0066] Table 1:

[0067] It should be noted that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. The orientation words "inside" and "outside" refer to the inside and outside relative to the outline of each component itself. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Therefore, the exemplary term "above..." can include both "above..." and "below..." orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here are interpreted accordingly.

[0068] It should also be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this application refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0069] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0070] It should also be noted that the above are only preferred embodiments of the present application, and the patent protection scope of the present application is not limited thereto. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for preparing a quasi-two-dimensional perovskite film, characterized in that: The following operations are included: According to the general formula of quasi-two-dimensional perovskite materials, corresponding raw materials are obtained; Mixing the raw materials, organic additives and solvent to obtain a precursor solution; Forming a film using the precursor solution, and annealing after drying to obtain a quasi-two-dimensional perovskite film; Wherein, the structural formula of the organic additive is shown in Formula I: In Formula I, R1 is selected from -S- or -O-; R2, R3, R4, and R5 are independently selected from -(CH2) n1 COOH, -(CH2) n2 CH(COOH)2, -(CH2) n3 C(COOH)3, -H, -OH, -(CH2) n4 CH3, and at least one of R2, R3, R4, and R5 is -(CH2) n1 COOH, -(CH2) n2 CH(COOH)2 or -(CH2) n3 C(COOH)3; n1, n2, n3, and n4 are each independently selected from integers between 0 and 6.

2. The method for preparing a quasi-two-dimensional perovskite film according to claim 1, characterized in that: R2 is -H or -COOH; R3 is -H, -CH(COOH)2 or -CH2COOH; R4 is -H; R5 is -H.

3. The method for preparing a quasi-two-dimensional perovskite film according to claim 2, characterized in that: The organic additives include: , , , , At least one of .

4. The method for preparing a quasi-two-dimensional perovskite film according to claim 1, characterized in that: The general formula of the quasi-two-dimensional perovskite film includes: A'2A n-1 B n X 3n+1 ; Wherein, A' is a monovalent organic ammonium cation, and n is a positive integer greater than or equal to 1.

5. The method for preparing a quasi-two-dimensional perovskite film according to claim 1, characterized in that: The general formula of the quasi-two-dimensional perovskite film includes: A''A n-1 B n X 3n+1 When A'' is a divalent organic ammonium cation, and n is a positive integer greater than or equal to 1.

6. The method for preparing a quasi-two-dimensional perovskite film according to claim 1, characterized in that: The raw materials include A 、 , AX and BX2; Among them, A 、 Including monoamine compounds or diamine compounds; A includes methylamine cation, formamidine cation, K + , Rb + , Cs + At least one of; B includes Pb 2+ ,Ge 2 + Sn 2+ , Cu 2+ 、Ni 2+ 、Co 2+ , Fe 2+ , Mn 2+ 、Eu 2+ At least one of; X includes Cl - Br - ,I - At least one of .

7. The method for preparing a quasi-two-dimensional perovskite film according to claim 1, characterized in that: The solvent includes N,N-dimethylformamide and / or dimethyl sulfoxide.

8. The method for preparing a quasi-two-dimensional perovskite film according to claim 1 or 7, characterized in that: The method of forming a film using the precursor solution and annealing the film after drying comprises the following operations: The film is formed by spin coating, then dried in a vacuum environment, and then annealed at 100°C to 150°C to obtain a quasi-two-dimensional perovskite film.

9. A quasi-two-dimensional perovskite film, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 8.

10. The quasi-two-dimensional perovskite film according to claim 9, characterized in that: The band gap of the quasi-two-dimensional perovskite film is 1.60 eV to 3.0 eV.

11. A perovskite photoactive layer, characterized in that: Including the quasi-two-dimensional perovskite film as described in claim 9 or 10.

12. A triple-junction stacked battery, characterized in that: It comprises a sub-cell, wherein the sub-cell comprises the perovskite photoactive layer according to claim 11.

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