Perovskite precursor solution, perovskite solar cell and preparation method thereof

Abstract

The embodiment of the invention provides a perovskite precursor solution, a perovskite solar cell and a preparation method thereof. The perovskite precursor solution comprises a perovskite material and a composite additive, wherein the perovskite material is of an ABX3 structure; a is a monovalent cation and comprises cesium; b is a divalent cation and comprises lead; x is a monovalent anion including iodine; the composite additive is a mixture of acetic acid and potassium acetate; or a mixture of monopotassium phosphate and monopotassium phosphate. According to the embodiment of the invention, the composite additive is introduced into the perovskite precursor solution, thereby not only passivating the defects of perovskite, but also maintaining the stability of the pH value of the perovskite precursor solution, and prolonging the storage time of the perovskite precursor solution, thereby improving the preparation repeatability of a perovskite device.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a perovskite precursor solution, a perovskite solar cell and a preparation method thereof, a photovoltaic module, and a photovoltaic system. Background Art

[0002] At present, thanks to the excellent photoelectric properties of organic-inorganic hybrid perovskites such as long carrier lifetime, high absorption coefficient, and good defect tolerance, the conversion efficiency of (single-junction) perovskite solar cells has reached more than 26% in just over a decade, and the efficiency of perovskite / crystalline silicon tandem solar cells has exceeded 33.9%, demonstrating the competitiveness of perovskite solar cells as the next generation of photovoltaic technology.

[0003] In the prior art, in order to improve the efficiency of perovskite solar cells, various bulk additives (such as Lewis base trans-ferulic acid) are added to the perovskite precursor to passivate the bulk defects of the perovskite film. Although the bulk additives can effectively passivate the defects of the perovskite, they cannot improve the stability of the precursor solution, resulting in the decrease in the preparation repeatability of the perovskite solar cell as the storage time of the precursor increases. Improving the stability of the precursor solution is crucial to improving the preparation repeatability of the perovskite film.

[0004] Therefore, there is an urgent need to study a perovskite precursor solution that can not only passivate the defects of perovskite, but also maintain the stability of the pH value of the perovskite precursor solution and increase the storage time of the perovskite precursor solution, thereby improving the repeatability of perovskite device preparation.

[0005] 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

[0006] The embodiments of the present application provide a perovskite precursor solution, a perovskite solar cell and a method for preparing the same, a photovoltaic module, and a photovoltaic system to solve or alleviate one or more of the technical problems raised above.

[0007] In a first aspect, an embodiment of the present application provides a perovskite precursor solution, comprising: a perovskite material and a composite additive;

[0008] Wherein, the perovskite material is an ABX3 structure; A is a monovalent cation, including cesium; B is a divalent cation, including lead; X is a monovalent anion, including iodine;

[0009] The composite additive is a mixture of acetic acid and potassium acetate; or

[0010] A mixture of potassium monohydrogen phosphate and potassium dihydrogen phosphate.

[0011] Optionally, the molar concentration ratio of the acetic acid to the potassium acetate is 1:3-3:1; or

[0012] The molar concentration ratio of the potassium monohydrogen phosphate to the potassium dihydrogen phosphate is 1:3-3:1.

[0013] Optionally, the molar concentration ratio of the composite additive to the perovskite material is (0%, 10%).

[0014] Optionally, A includes a mixture of one or more monovalent cations selected from cesium, rubidium, methylamine, and guanidine; B also includes a mixture of one or more divalent cations selected from copper, zinc, gallium, tin, and calcium; and X also includes a mixture of one or more monovalent anions selected from bromine, chlorine, fluorine, and thiocyanate.

[0015] Optionally, the perovskite precursor solution further includes an organic solvent for dissolving the perovskite material and the composite additive, and the organic solvent includes one or more of N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, 2-methoxyethanol, dimethylacetamide, and N,N'-dimethylpropylene urea.

[0016] In a second aspect, an embodiment of the present application provides a perovskite solar cell, comprising a conductive substrate, a transparent conductive oxide layer, a hole transport layer, a perovskite light absorption layer, an electron transport layer, and a back electrode stacked in sequence;

[0017] Wherein, the perovskite light absorbing layer is prepared from a perovskite precursor solution according to any one of the above embodiments.

[0018] Optionally, the thickness of the perovskite light absorbing layer is 0.3 μm-1.4 μm.

[0019] In a third aspect, an embodiment of the present application provides a method for preparing a perovskite solar cell, comprising:

[0020] providing a conductive substrate;

[0021] Depositing a transparent conductive oxide layer on the surface of the conductive substrate;

[0022] forming a hole transport layer on the surface of the transparent conductive oxide layer;

[0023] forming a perovskite light absorbing layer on the surface of the hole transport layer;

[0024] forming an electron transport layer on the surface of the perovskite light absorbing layer;

[0025] forming a back electrode on a surface of the electron transport layer;

[0026] Wherein, the perovskite light absorbing layer is prepared from a perovskite precursor solution according to any one of the above embodiments.

[0027] Optionally, forming a perovskite light absorbing layer comprises:

[0028] Spin coating the precursor solution on the surface of the hole transport layer;

[0029] adding an antisolvent to the precursor solution during spin coating;

[0030] The spin-coated perovskite film is annealed.

[0031] Optionally, during the spin coating process, the rotation speed is 1000 rpm-4000 rpm.

[0032] Optionally, the anti-solvent includes one or more of anisole, chlorobenzene, and diethyl carbonate.

[0033] In a fourth aspect, an embodiment of the present application provides a photovoltaic module, comprising: at least one battery string, wherein the battery string comprises at least two perovskite solar cells of any one of the above items.

[0034] In a fifth aspect, an embodiment of the present application provides a photovoltaic system, comprising the above-mentioned photovoltaic assembly.

[0035] The above technical solution adopted in the embodiment of the present application may have the following advantages:

[0036] By introducing composite additives such as acetic acid (CH3COOH) and potassium acetate (CH3COOK), or potassium monohydrogen phosphate (K2HPO4) and potassium dihydrogen phosphate (KH2PO4) into the perovskite precursor solution, not only the defects of the perovskite are passivated, but also the stability of the pH value of the perovskite precursor solution can be maintained, the storage time of the perovskite precursor solution is increased, and thus the repeatability of the preparation of perovskite devices is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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.

[0038] Figure 1 is a schematic diagram of the structure of a perovskite solar cell provided in an embodiment of the present application;

[0039] Figure 2 is a flow chart of a method for preparing a perovskite solar cell according to an embodiment of the present application;

[0040] Figure 3 It is a transient photoluminescence image of a perovskite film provided by an embodiment of the present application and a comparison;

[0041] Figure 4 1 is a device efficiency diagram provided by an embodiment of the present application and a pair of ratios.

[0042] Description of reference numerals:

[0043] 11 Conductive substrate

[0044] 12 Transparent Conductive Oxide Layer

[0045] 13. Hole transport layer

[0046] 14 Perovskite light-absorbing layer

[0047] 15 Electron transport layer

[0048] 16 Back electrode DETAILED DESCRIPTION

[0049] 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.

[0050] 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 disclosure, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. And when the second element, component, region, layer or part is discussed, it does not mean that the present disclosure necessarily has the first element, component, region, layer or part.

[0051] 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.

[0052] 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.

[0053] The following provides an explanation of the terms used in this application.

[0054] Perovskite precursor solution: Perovskite precursor solution is a solution used to prepare perovskite thin film, usually containing organic iodine compounds, inorganic lead compounds, solvents and other ingredients. These solutions are generally used to form precursors of perovskite thin films on the surface of substrates through processes such as spin coating.

[0055] ITO: Indium tin oxide is a transparent conductive material made by mixing indium oxide (In2O3) and tin oxide (SnO2). It can be used as a transparent electrode material in photovoltaic cells and is used to make the front electrode of photovoltaic cells.

[0056] Molar concentration ratio: refers to the ratio of the molar concentrations of two or more substances in a mixed solution. Molar concentration is the ratio of the number of moles of solute in a solution to the volume of the solution.

[0057] To facilitate those skilled in the art to understand the technical solutions provided in the embodiments of the present application, the relevant technologies are described below:

[0058] The embodiment of the present application provides a perovskite precursor solution, including: a perovskite material, a composite additive and an organic solvent. The composite additive is acetic acid and potassium acetate, or potassium monohydrogen phosphate and potassium dihydrogen phosphate, and the organic solvent includes N,N-dimethylformamide and dimethyl sulfoxide. Among them, the composite additive and the metal ions in the perovskite precursor solution can coordinate with each other, and this coordination effect can reduce the defect state density in the perovskite film. At the same time, the composite additive is a conjugate acid-base pair, which can provide a buffering effect, thereby maintaining the pH value of the solution stable. At the same time, the composite additive can chelate metal ions to prevent metal ions from reacting with other substances. Therefore, the addition of the composite additive not only passivates the defects of the perovskite, but also maintains the stability of the perovskite precursor solution, improves the storage time of the perovskite precursor solution, and thus improves the repeatability of the preparation of perovskite devices. For details, please refer to the following.

[0059] 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.

[0060] The embodiment of the present application provides a titanium ore precursor solution, including: a perovskite material and a composite additive;

[0061] The perovskite material is an ABX3 structure; A is a monovalent cation, including cesium; B is a divalent cation, including lead; X is a monovalent anion, including iodine;

[0062] The composite additive is a mixture of acetic acid and potassium acetate; or a mixture of potassium monohydrogen phosphate and potassium dihydrogen phosphate.

[0063] The perovskite precursor solution of the embodiment of the present application includes a perovskite material and a composite additive. Among them, when the composite additive is acetic acid and potassium acetate, acetic acid as a weak acid can coordinate with Pb2+ in the perovskite material, control the nucleation rate, promote crystal growth, and improve the uniformity and grain size of the film. Potassium acetate can provide K+ ions, which can passivate defects and improve the stability of the film. When the composite additive is potassium monohydrogen phosphate and potassium dihydrogen phosphate, potassium monohydrogen phosphate and potassium dihydrogen phosphate can both provide PO43- ions, which can react with Pb2+ to form a complex reaction and regulate the morphology and grain size of the perovskite film. Adding the above-mentioned composite additive in the embodiment of the present application not only passivates the defects of the perovskite, but also maintains the stability of the pH value of the perovskite precursor solution, improves the storage time of the perovskite precursor solution, and thus improves the repeatability of the preparation of perovskite devices.

[0064] In an optional embodiment, the molar concentration ratio of acetic acid to potassium acetate is 1:3-3:1; or the molar concentration ratio of potassium monohydrogen phosphate to potassium dihydrogen phosphate is 1:3-3:1. Exemplarily, the molar concentration ratio of acetic acid to potassium acetate is 1:3, 1:2, 1:1, 2.5:1.5 or 3:1; or the molar concentration ratio of potassium monohydrogen phosphate to potassium dihydrogen phosphate is 1:3, 1:2, 1:1, 2.5:1.5 or 3:1. In the perovskite precursor solution of this embodiment, acetic acid and potassium acetate / potassium monohydrogen phosphate and potassium dihydrogen phosphate can act synergistically in the molar concentration range of 1:3-3:1, effectively passivating perovskite defects while maintaining the stability of the pH value of the perovskite precursor solution.

[0065] In an optional embodiment, the molar concentration ratio of the composite additive to the perovskite material is (0%, 10%]. Exemplarily, the molar concentration ratio of the composite additive to the perovskite material is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%. In the present embodiment, the range of (0%, 10%] is an open interval of 0% to a closed interval of 10%. Experiments have shown that the molar concentration of the composite additive to the perovskite material within this range can effectively passivate perovskite defects while maintaining the stability of the pH value of the perovskite precursor solution.

[0066] In an optional embodiment, A includes a mixture of one or more monovalent cations selected from cesium, rubidium, methylamine, and guanidine; B also includes a mixture of one or more divalent cations selected from copper, zinc, gallium, tin, and calcium; and X also includes a mixture of one or more monovalent anions selected from bromine, chlorine, fluorine, and thiocyanate.

[0067] In an optional embodiment, the perovskite precursor solution also includes an organic solvent for dissolving the perovskite material and the composite additive, and the organic solvent includes one or more of N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, 2-methoxyethanol, dimethylacetamide, and N,N'-dimethylpropylene urea. Among them, N,N-dimethylformamide has a high solubility, can dissolve the perovskite precursor material, and has a high boiling point, which can improve the film quality of the film. In addition, the organic solvent can also include dimethyl sulfoxide, which has a high polarity, can promote the dissolution of the perovskite precursor material, and has a low volatility, which can improve the compactness of the film. Among them, the proportion of the organic solvent needs to be adjusted according to the specific circumstances to obtain the best battery performance. It is necessary to pay attention to the toxicity and safety of the organic solvent and take necessary protective measures. The optional organic solvents in the embodiments of the present application all have the following characteristics: they can dissolve the perovskite precursor material, have good volatility or have a high boiling point to improve the film quality of the film, and have good compatibility with other materials.

[0068] The present application embodiment provides a perovskite solar cell. Figure 1 The perovskite solar cell includes a conductive substrate 11, a transparent conductive oxide layer 12, a hole transport layer 13, a perovskite light absorbing layer 14, an electron transport layer 15, and a back electrode 16 which are stacked in sequence;

[0069] The perovskite light absorbing layer 14 is prepared from a perovskite precursor solution according to any one of the above embodiments.

[0070] The perovskite solar cell in the embodiment of the present application includes a conductive substrate 11, a transparent conductive oxide layer 12, a hole transport layer 13, a perovskite light absorbing layer 14, an electron transport layer 15, and a back electrode 16. Among them, the conductive substrate 11 provides support for the battery and collects current, the transparent conductive oxide layer 12 improves the light transmittance and collection efficiency of the battery, the perovskite light absorbing layer 14 absorbs photons and generates electron-hole pairs, the hole transport layer 13 obtains holes in the perovskite light absorbing layer 14, the electron transport layer 15 obtains electrons in the perovskite light absorbing layer 14, and the back electrode 16 collects electrons and forms a loop. The above structure constitutes a relatively complete perovskite solar cell, wherein the perovskite light absorbing layer 14 is composed of a perovskite film, and the perovskite film is prepared from a perovskite precursor solution. In this embodiment, the composite additives acetic acid and potassium acetate (potassium monohydrogen phosphate and potassium dihydrogen phosphate) are added to the perovskite precursor solution, which not only passivates the defects of the perovskite, but also maintains the stability of the pH value of the perovskite precursor solution, improves the storage time of the perovskite precursor solution, and thus improves the repeatability of the preparation of perovskite devices.

[0071] In an optional embodiment, the molar concentration ratio of acetic acid to potassium acetate is 1:3-3:1; or the molar concentration ratio of potassium monohydrogen phosphate to potassium dihydrogen phosphate is 1:3-3:1. Exemplarily, the molar concentration ratio of acetic acid to potassium acetate is 1:3, 1:2, 1:1, 2.5:1.5 or 3:1; or the molar concentration ratio of potassium monohydrogen phosphate to potassium dihydrogen phosphate is 1:3, 1:2, 1:1, 2.5:1.5 or 3:1. In the perovskite precursor solution of this embodiment, acetic acid and potassium acetate / potassium monohydrogen phosphate and potassium dihydrogen phosphate can act synergistically in the molar concentration range of 1:3-3:1, effectively passivating perovskite defects while maintaining the stability of the pH value of the perovskite precursor solution.

[0072] In an optional embodiment, the molar concentration ratio of the composite additive to the perovskite material is (0%, 10%], illustratively, the molar concentration ratio of the composite additive to the perovskite material is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%. In the present embodiment, the range of (0%, 10%] is an open interval of 0% to a closed interval of 10%. Experiments have shown that the molar concentration of the composite additive to the perovskite material within this range can effectively passivate perovskite defects while maintaining the stability of the pH value of the perovskite precursor solution.

[0073] In an optional embodiment, the thickness of the perovskite light absorbing layer is 0.3 μm-1.4 μm. Exemplarily, the thickness of the perovskite film is 0.3 μm, 0.5 μm, 0.7 μm, 0.9 μm, 1.1 μm or 1.4 μm.

[0074] If the thickness of the perovskite light-absorbing layer is too thin, the composite additives in the perovskite precursor solution will not be able to effectively penetrate and evenly distribute throughout the perovskite layer, resulting in a weakened pH stability effect. In addition, a thinner perovskite light-absorbing layer may produce too many grain boundary defects, thereby affecting the performance of perovskite solar cells. If the thickness of the perovskite light-absorbing layer is too thick, the composite additives may have difficulty in evenly penetrating the entire perovskite light-absorbing layer, which will cause pH fluctuations in local areas, thereby affecting the stability of the perovskite light-absorbing layer.

[0075] The thickness range of the perovskite light absorbing layer provided in the embodiment of the present application enables the composite additive to be evenly distributed throughout the perovskite light absorbing layer, thereby effectively passivating the perovskite crystal defects and maintaining the pH stability of the precursor solution. In addition, the thickness range of the perovskite light absorbing layer provided in the embodiment of the present application will effectively affect the absorption efficiency of the composite additive and the light absorption efficiency, carrier transmission efficiency, battery efficiency, etc. of the battery, and the specific value of the thickness can be adjusted according to the specific material and battery structure.

[0076] In an optional embodiment, the transparent conductive oxide layer 12 includes one or more of indium tin oxide, zinc oxide, and fluorine-doped tin oxide. In this embodiment, the selected materials have high light transmittance, ensuring the overall light transmittance of the optical device, low resistivity, good electrical conductivity, good chemical stability and thermal stability, and can maintain stable performance in the application environment.

[0077] In an optional embodiment, the hole transport layer 13 includes one or more of [2-(9H-carbazole-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid, and nickel oxide. In this embodiment, the materials selected for preparing the hole transport layer 13 have the following characteristics: good hole transport ability, good interface matching with the perovskite layer, high oxidation stability, and suitable energy level. Selecting a suitable hole transport layer material from the optional materials provided in this embodiment can enhance the stability of the device, improve the ability of the device to operate stably for a long time, and reduce the performance degradation of the device under environmental conditions such as light and humidity.

[0078] In an optional embodiment, the electron transport layer 15 includes one or more of SnO2, ZnO, ZrO2, fullerene, and fullerene derivatives. The optional materials of the electron transport layer 15 provided in this embodiment all have the following characteristics: high electron mobility, energy level matching with the perovskite light absorption layer 14, and good stability.

[0079] In an optional embodiment, the back electrode 16 includes one or more of silver, gold, and copper. The optional materials provided in this embodiment all have high electrical conductivity. Selecting them as the components of the back electrode can reduce resistance and improve electron transmission efficiency, thereby enhancing the electrical performance of the solar cell device.

[0080] The present invention provides a method for preparing a perovskite solar cell. Figure 2 , the preparation method of the perovskite solar cell comprises:

[0081] S10: providing a conductive substrate;

[0082] S11: depositing a transparent conductive oxide layer on the surface of the conductive substrate;

[0083] S12: forming a hole transport layer on the surface of the transparent conductive oxide layer;

[0084] S13: forming a perovskite light absorption layer on the surface of the hole transport layer;

[0085] S14: forming an electron transport layer on the surface of the perovskite light absorbing layer;

[0086] S15: forming a back electrode on the surface of the electron transport layer;

[0087] Wherein, the perovskite light absorbing layer is prepared from a perovskite precursor solution according to any one of the above embodiments.

[0088] In this embodiment, a method for preparing a wide bandgap perovskite solar cell specifically includes the following steps:

[0089] (1) treating the ITO conductive substrate with UV ozone for 15 minutes;

[0090] (2) A 15 nm NiOx hole transport layer was prepared by magnetron sputtering, and NiOx was further modified by 2PACz;

[0091] (3) using CsI, FAI, PbI2, and PbBr2 to prepare a perovskite precursor solution with a composition of FA0.8Cs0.2PbI1.8Br1.2, the solvent is a mixed solution of DMF / DMSO, and acetic acid and potassium acetate buffer materials are added as additives;

[0092] (4) using a one-step anti-solvent method, anisole was used as an anti-solvent to prepare the perovskite film, and the annealing conditions were 120 °C for 20 min;

[0093] 5) a 15 nm thick C60 electron transport layer was deposited by thermal evaporation, and a 15 nm thick SnO2 barrier layer was prepared by atomic layer deposition;

[0094] (6) A 150 nm thick Ag back electrode was deposited by thermal evaporation.

[0095] In an optional embodiment, the method for forming a hole transport layer includes:

[0096] Nickel oxide is magnetron sputtered on the transparent conductive oxide on the surface of the conductive substrate, and the thickness of the nickel oxide is 5nm-20nm. Magnetron sputtering deposition technology refers to the use of high-energy ions to bombard nickel oxide targets under vacuum conditions, and the sputtered atoms are deposited on the transparent conductive oxide (TCO) layer to form a nickel oxide film. The film prepared by the magnetron sputtering deposition technology in this embodiment has the advantages of uniform thickness, high crystallinity, and strong adhesion. In this embodiment, the thickness of nickel oxide will effectively affect the performance of the hole transport layer. A hole transport layer that is too thin cannot effectively extract holes, and a hole transport layer that is too thick will increase the series resistance of the battery. In this embodiment, 5nm-20nm is the optimal thickness range of the nickel oxide hole transport layer. Among them, the material used to form the hole transport layer is nickel oxide, because nickel oxide has good conductivity and hole transport ability, and can effectively extract holes from the perovskite light absorption layer.

[0097] In an optional embodiment, the forming of the perovskite light absorbing layer comprises:

[0098] Spin coating the precursor solution on the surface of the hole transport layer;

[0099] adding an antisolvent to the precursor solution during spin coating;

[0100] The spin-coated perovskite film is annealed.

[0101] In an optional embodiment, during the spin coating process, the rotation speed is 1000rpm-4000rpm. In this embodiment, the principle of spin coating is to drop the precursor solution onto a substrate rotating at a high speed, and spread the solution evenly by centrifugal force to form a thin film. The rotation speed provided in this embodiment can effectively control the film thickness, film uniformity and film morphology of the perovskite film.

[0102] In an optional embodiment, the anti-solvent includes one or more of anisole, chlorobenzene, and diethyl carbonate. In this embodiment, the anti-solvent is mixed with the solvent in the precursor solution to accelerate the volatilization rate of the solvent, thereby promoting the growth of perovskite crystals and controlling the morphology of the perovskite film.

[0103] In an optional embodiment, during the annealing process of forming the perovskite film, the temperature is 100°C-130°C, and the time is 10min-40min. Preferably, the temperature can be 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, and the time can be 10min, 20min, 30min, 40min. In this embodiment, the above annealing treatment can remove solvent residues, promote further growth of perovskite crystals, and improve the crystallinity and photoelectric properties of the perovskite film.

[0104] In an optional embodiment, the electron transport layer includes a fullerene layer and a barrier layer;

[0105] Wherein, the forming of the electron transport layer comprises:

[0106] After the fullerene layer is formed on the surface of the perovskite light absorbing layer, a barrier layer is formed on the side of the fullerene layer away from the perovskite light absorbing layer. In this embodiment, the electron transport layer includes but is not limited to C60, PCBM, and SnO2. Among them, the fullerene layer obtains electrons from the perovskite light absorbing layer, thereby improving the electron transport efficiency of the battery. The preparation method of the fullerene layer and the barrier layer may include solution deposition, magnetron sputtering, etc. The fullerene layer and the barrier layer together constitute the electron transport layer, and an energy level difference is formed between the two, which is conducive to the transmission of electrons from the perovskite light absorbing layer to the electron transport layer.

[0107] In an optional embodiment, the material of the barrier layer includes tin dioxide, and the thickness of the barrier layer is 10nm-20nm. For example, the thickness of the barrier layer is 10nm, 12nm, 14nm, 16nm, 18nm or 20nm. In this embodiment, the provision of the barrier layer can effectively promote the transmission of electrons from the fullerene layer to the back electrode, thereby increasing the open circuit voltage of the battery and helping to improve the performance and stability of the device.

[0108] The following specific examples further illustrate the present application, but should not be construed as limiting the present application. Without departing from the spirit and substance of the present application, modifications or replacements made to the methods, steps or conditions of the present application are within the scope of the present application.

[0109] [Example 1]

[0110] like Figure 1 As shown, the specific structure of a perovskite solar cell is:

[0111] A conductive substrate 11, a transparent conductive oxide layer 12, a hole transport layer 13, a perovskite light absorption layer 14, an electron transport layer 15, and a back electrode 16 are stacked in sequence.

[0112] like Figure 2 As shown, the specific preparation process of a perovskite solar cell is as follows:

[0113] S10: providing a conductive substrate;

[0114] S11: depositing a transparent conductive oxide layer on the surface of the conductive substrate;

[0115] S12: forming a hole transport layer on the surface of the transparent conductive oxide layer;

[0116] S13: forming a perovskite light absorption layer on the surface of the hole transport layer;

[0117] S14: forming an electron transport layer on the surface of the perovskite light absorbing layer;

[0118] S15: forming a back electrode on the surface of the electron transport layer;

[0119] Among them, step S11 includes sub-steps S102-S103, step S12 includes sub-step S104, step S13 includes sub-step S101 and sub-steps S105-S106, step S14 includes sub-step S107, and step S15 also includes sub-step S108. Sub-steps S101-S108 are described as follows:

[0120] S101: The perovskite material, the composite additive (acetic acid and potassium acetate / potassium monohydrogen phosphate and potassium dihydrogen phosphate), and the organic solvent (N,N-dimethylformamide and dimethyl sulfoxide) are uniformly mixed to prepare a perovskite precursor solution; wherein the perovskite material is an ABX3 structure; A is a monovalent cation; B is a divalent cation, including lead (Pb); X is a monovalent anion, including iodine (I); the molar concentration ratio of acetic acid and potassium acetate is 1:1; and the molar concentration ratio of the composite additive to the perovskite material is 1%.

[0121] S102: Clean the conductive substrate and deposit transparent oxide on the surface thereof to form an ITO conductive substrate. The thickness of the ITO conductive substrate is 15 nm.

[0122] S103: The ITO conductive substrate is subjected to ultraviolet ozone treatment, the wavelength of the ultraviolet light source is 185 nm, the concentration of the ozone gas is 500 ppm, and the treatment time is 15 minutes.

[0123] S104: A NiOx hole transport layer is formed on the surface of the ITO conductive substrate by magnetron sputtering. The thickness of the NiOx hole transport layer is 15 nm.

[0124] S105: spin-coating the precursor solution on the surface of the hole transport layer to form a perovskite film by using an anti-solvent method, with a rotation speed of 2000 rpm. During the spin coating process, anti-solvent is dripped onto the surface of the perovskite film. The thickness of the perovskite film is 500 nm.

[0125] S106: performing annealing treatment on the obtained perovskite film at a temperature of 120° C. for 20 minutes.

[0126] S107: Using a thermal evaporation method, an electron transport layer is deposited on the surface of the perovskite film. The electron transport layer includes a fullerene layer and a barrier layer. First, a 15 nm thick C60 fullerene layer is deposited on the surface of the perovskite film, and then a 15 nm thick SnO2 barrier layer is prepared using an atomic layer deposition method.

[0127] S108: Using a thermal evaporation method, a 150 nm Ag back electrode is deposited on the surface of the electron transport layer.

[0128] [Example 2]

[0129] The perovskite solar cell of Example 2 was prepared by referring to the preparation method of Example 1, except that S101 of Example 2 was: the perovskite material, the composite additive (acetic acid and potassium acetate / potassium monohydrogen phosphate and potassium dihydrogen phosphate), and the organic solvent (N,N-dimethylformamide and dimethyl sulfoxide) were uniformly mixed to prepare a perovskite precursor solution; wherein the perovskite material was an ABX3 structure; A was a monovalent cation, including cesium (Cs), rubidium (Rb), methylamine (CH3NH3), guanidine (CH2(NH2 )2) is a mixture of one or more monovalent cations; B is a divalent cation, including a mixture of one or more divalent cations of lead (Pb), copper (Cu), zinc (Zn), gallium (Ga), tin (Sn), and calcium (Ca); X is a monovalent anion, including a mixture of one or more monovalent anions of iodine (I), bromine (Br), chlorine (Cl), fluorine (F), and thiocyanate ion (SCN); the molar concentration ratio of acetic acid to potassium acetate is 1:2; the molar concentration ratio of the composite additive to the perovskite material is 1%;

[0130] [Example 3]

[0131] The perovskite solar cell of Example 3 was prepared by referring to the preparation method of Example 1, except that S101 of Example 3 was as follows: the perovskite material, the composite additive (acetic acid and potassium acetate / potassium monohydrogen phosphate and potassium dihydrogen phosphate), and the organic solvent (N,N-dimethylformamide and dimethyl sulfoxide) were uniformly mixed to prepare a perovskite precursor solution; wherein the perovskite material was an ABX3 structure; A was a monovalent cation; B was a divalent cation, including lead (Pb); X was a monovalent anion, including iodine (I); the organic solvent included one or more of acetonitrile, 2-methoxyethanol, dimethylacetamide, and N,N'-dimethylpropylene urea; the molar concentration ratio of potassium monohydrogen phosphate to potassium dihydrogen phosphate was 1:1; the molar concentration ratio of the composite additive to the perovskite material was 2%;

[0132] [Comparative Example 1]

[0133] The perovskite solar cell of Comparative Example 1 was prepared by referring to the preparation method of Example 1, except that S101 of Comparative Example 1 was as follows: the perovskite material and the organic solvent (N,N-dimethylformamide and dimethyl sulfoxide) were evenly mixed to prepare a perovskite precursor solution; wherein the perovskite material was an ABX3 structure; A was a monovalent cation; B was a divalent cation, including lead (Pb); and X was a monovalent anion, including iodine (I).

[0134] The following is a performance test of the perovskite solar cells provided in Examples 1-3 of the present application and Comparative Example 1, so as to obtain the open circuit voltage VOC, photoelectric conversion efficiency PCE, fill factor FF, and short circuit current density Jsc of the corresponding battery devices. The test results are shown in Table 1.

[0135] Table 1 Performance test results of perovskite solar cells of Examples 1-3 and Comparative Example 1

[0136]

[0137]

[0138] In addition, the present application also provides transient photoluminescence images of the perovskite film prepared from the precursor solution obtained in Comparative Example 1 (Control) and Example 1 (Target) after being placed for 20 days and the corresponding device efficiency images. Figure 3 As shown in the figure, the device efficiency is Figure 4 shown.

[0139] pass Figure 3 It can be seen that compared with Comparative Example 1 (Control), the luminescence intensity decay rate of the perovskite light-absorbing layer prepared from the precursor solution obtained in Example 1 (Target) after being placed for 20 days is significantly lower, while Figure 4 It can be seen that the device corresponding to the perovskite light absorption layer prepared in Example 1 (Target) has a higher efficiency. That is, compared with Comparative Example 1 (Control), the perovskite solar cell obtained in Example 1 (Target) is more stable.

[0140] It can be seen from Table 1 above that, compared with Comparative Example 1, the open circuit voltage, photoelectric conversion efficiency, fill factor and short circuit current density of the perovskite solar cells of Examples 1-3 of the present application are significantly improved.

[0141] In summary, the embodiment of the present application prepares a perovskite precursor solution using perovskite materials, acetic acid and potassium acetate (potassium monohydrogen phosphate and potassium dihydrogen phosphate) and organic solvents (N,N-dimethylformamide and dimethyl sulfoxide). Among them, N,N-dimethylformamide has a high solubility and can dissolve perovskite precursor materials, and has a high boiling point, which can improve the film quality of the film. The organic solvent also includes dimethyl sulfoxide, which has a high polarity and can promote the dissolution of perovskite precursor materials. It has low volatility and can improve the density of the film. The composite additives acetic acid and potassium acetate (potassium monohydrogen phosphate and potassium dihydrogen phosphate) can passivate the defects of perovskite while maintaining the stability of the pH value of the perovskite precursor solution, thereby improving the storage time of the perovskite precursor solution and improving the repeatability of the preparation of perovskite devices.

[0142] The embodiment of the present application may also provide a photovoltaic module (not shown), including at least one battery string, the battery string includes at least two perovskite solar cells as described above, and adjacent perovskite solar cells can be connected together by series welding.

[0143] The embodiment of the present application can provide a photovoltaic system, including the photovoltaic components in any of the above embodiments. The advantages of the above photovoltaic components are also possessed by the photovoltaic system, which will not be repeated here. The above photovoltaic system has a wide range of applications, not only limited to photovoltaic power stations, such as ground power stations, rooftop power stations and water power stations, but also includes various equipment and devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars and solar buildings. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is to say, the photovoltaic system can be used in all fields where solar energy is required for power generation. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array may be an array combination of multiple photovoltaic components. For example, multiple photovoltaic components may form multiple photovoltaic arrays. The photovoltaic array is connected to a junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter and is converted into the alternating current required by the mains power grid, and then connected to the mains network to realize solar power supply.

[0144] 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.

[0145] 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 a specific feature, structure or characteristic is described 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.

[0146] 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.

[0147] 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 perovskite precursor solution, characterized in that: include: Perovskite materials and composite additives; Wherein, the perovskite material is an ABX3 structure; A is a monovalent cation, including cesium; B is a divalent cation, including lead; X is a monovalent anion, including iodine; The composite additive is a mixture of acetic acid and potassium acetate; or A mixture of potassium monohydrogen phosphate and potassium dihydrogen phosphate.

2. The perovskite precursor solution according to claim 1, characterized in that The molar concentration ratio of the acetic acid to the potassium acetate is 1:3-3:1; or The molar concentration ratio of the potassium monohydrogen phosphate to the potassium dihydrogen phosphate is 1:3-3:

1.

3. The perovskite precursor solution according to claim 1, characterized in that The molar concentration ratio of the composite additive to the perovskite material is (0%, 10%).

4. The perovskite precursor solution according to any one of claims 1 to 3, characterized in that: The A includes a mixture of one or more monovalent cations selected from cesium, rubidium, methylamine, and methylamidine; the B also includes a mixture of one or more divalent cations selected from copper, zinc, gallium, tin, and calcium; and the X also includes a mixture of one or more monovalent anions selected from bromine, chlorine, fluorine, and thiocyanate.

5. The perovskite precursor solution according to any one of claims 1 to 3, characterized in that: The perovskite precursor solution also includes an organic solvent for dissolving the perovskite material and the composite additive, and the organic solvent includes one or more of N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, 2-methoxyethanol, dimethylacetamide, and N,N'-dimethylpropylene urea.

6. A perovskite solar cell, characterized in that: It includes a conductive substrate, a transparent conductive oxide layer, a hole transport layer, a perovskite light absorption layer, an electron transport layer, and a back electrode which are stacked in sequence; Wherein, the perovskite light absorbing layer is prepared from the perovskite precursor solution according to any one of claims 1 to 5.

7. The perovskite solar cell according to claim 6, characterized in that: The thickness of the perovskite light absorbing layer is 0.3 μm-1.4 μm.

8. A method for preparing a perovskite solar cell, characterized in that: include: providing a conductive substrate; Depositing a transparent conductive oxide layer on the surface of the conductive substrate; forming a hole transport layer on the surface of the transparent conductive oxide layer; forming a perovskite light absorbing layer on the surface of the hole transport layer; forming an electron transport layer on the surface of the perovskite light absorbing layer; forming a back electrode on a surface of the electron transport layer; Wherein, the perovskite light absorbing layer is prepared from the perovskite precursor solution according to any one of claims 1 to 5.

9. The method for preparing a perovskite solar cell according to claim 8, characterized in that: The forming of the perovskite light absorbing layer comprises: Spin coating the precursor solution on the surface of the hole transport layer; adding an antisolvent to the precursor solution during spin coating; The spin-coated perovskite film is annealed.

10. The method for preparing a perovskite solar cell according to claim 9, characterized in that: During the spin coating process, the rotation speed is 1000 rpm-4000 rpm.

11. The method for preparing a perovskite solar cell according to any one of claims 9 to 10, characterized in that: The anti-solvent includes one or more of anisole, chlorobenzene, and diethyl carbonate.

12. A photovoltaic module, characterized in that: include: At least one cell string, the cell string comprising at least three perovskite solar cells as claimed in any one of claims 6 to 7.

13. A photovoltaic system, characterized in that: Comprising the photovoltaic module as claimed in claim 12.

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