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 of the perovskite solar cell. The perovskite precursor solution comprises a perovskite material and double additives, 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 double additives are ammonium iodide and potassium acetate. According to the embodiment of the invention, double additives are introduced into the perovskite precursor solution, thereby not only passivating the defects of perovskite, but also improving the crystal quality of a perovskite thin film, thereby improving the performance of a perovskite solar cell.

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, perovskite solar cells have received extensive attention and have good development potential and application prospects. However, (wide bandgap) perovskite solar cells generally have the problem of poor crystal quality of the perovskite light-absorbing layer. The poor film quality leads to more defect states in the perovskite film, so the opening voltage loss (V OC This seriously restricts the development of wide-bandgap perovskite solar cells. Therefore, improving the film quality through defect passivation and crystallization regulation is crucial to improving the performance of wide-bandgap perovskite solar cells.

[0003] In order to passivate the defects of wide-bandgap perovskite films, the prior art adds KI (potassium iodide) into wide-bandgap perovskite. The addition of KI can not only inhibit phase separation, but also effectively passivate the crystal defects of perovskite, thereby increasing the V of wide-bandgap perovskite solar cell devices. OC The losses were reduced from 152mV to 92mV in the undoped state, indicating that the incorporation of potassium iodide effectively reduced the non-radiative recombination of wide-bandgap perovskites. However, although the KI additive passivates the crystal defects of the perovskite, the improvement in the crystallization quality of the perovskite film is relatively limited, and therefore the performance improvement of the perovskite solar cell is limited.

[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 perovskite precursor solution, a perovskite solar cell and a preparation method thereof, a photovoltaic module, and a photovoltaic system to solve or alleviate the technical problems raised above.

[0006] In a first aspect, an embodiment of the present application provides a perovskite precursor solution, comprising: a perovskite material and a dual additive;

[0007] 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;

[0008] The dual additives are ammonium iodide and potassium acetate.

[0009] Optionally, the molar concentration ratio of the ammonium iodide to the potassium acetate is 1:2-2:1.

[0010] Optionally, the molar concentration ratio of the dual additives to the perovskite material is (0%, 6%).

[0011] 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.

[0012] Optionally, the organic solvent includes one or more of N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, 2-methoxyethanol, dimethylacetamide, and N,N'-dimethylpropylene urea.

[0013] 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;

[0014] Wherein, the perovskite light absorbing layer is prepared from a perovskite precursor solution according to any one of the above embodiments.

[0015] Optionally, the thickness of the perovskite light absorbing layer is 500 nm-1.6 μm, and the band gap of the perovskite light absorbing layer is 1.61 eV-1.79 eV.

[0016] In a third aspect, an embodiment of the present application provides a method for preparing a perovskite solar cell, comprising:

[0017] providing a conductive substrate;

[0018] Depositing a transparent conductive oxide layer on the surface of the conductive substrate;

[0019] forming a hole transport layer on the surface of the transparent conductive oxide layer;

[0020] forming a perovskite light absorbing layer on the surface of the hole transport layer;

[0021] forming an electron transport layer on the surface of the perovskite light absorbing layer;

[0022] forming a back electrode on a surface of the electron transport layer;

[0023] Wherein, the perovskite light absorbing layer is prepared from a perovskite precursor solution according to any one of the above embodiments.

[0024] Optionally, forming a perovskite light absorbing layer on the surface of the hole transport layer comprises:

[0025] Spin coating the precursor solution on the surface of the hole transport layer;

[0026] adding an antisolvent to the precursor solution during spin coating;

[0027] The spin-coated perovskite film is annealed.

[0028] Optionally, during the spin coating process, the rotation speed is 1000 rpm-4000 rpm.

[0029] Optionally, the anti-solvent includes any one of anisole, chlorobenzene, and diethyl carbonate.

[0030] 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.

[0031] In a fifth aspect, an embodiment of the present application provides a photovoltaic system, comprising the above-mentioned photovoltaic assembly.

[0032] The above technical solution adopted in the embodiment of the present application may have the following advantages:

[0033] By introducing two additives, ammonium iodide (NH4I) and potassium acetate (CH3COOK), into the perovskite precursor solution, not only the defects of the perovskite are passivated, but also the crystallization quality of the perovskite film can be improved, thereby improving the performance of perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] 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.

[0035] Figure 1 is a schematic diagram of the structure of a perovskite solar cell provided in an embodiment of the present application;

[0036] Figure 2 is a flow chart of a method for preparing a perovskite solar cell according to an embodiment of the present application;

[0037] Figure 3 It is an XRD (X-ray diffraction) diagram of a perovskite light absorbing layer provided in one embodiment of the present application and a comparison;

[0038] Figure 4 It is a PL mapping (photoluminescence mapping) diagram of a perovskite film provided in one embodiment of the present application and a comparison.

[0039] Description of reference numerals:

[0040] 11 Conductive substrate

[0041] 12 Transparent Conductive Oxide Layer

[0042] 13. Hole transport layer

[0043] 14 Perovskite light-absorbing layer

[0044] 15 Electron transport layer

[0045] 16 Back electrode DETAILED DESCRIPTION

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] The following provides an explanation of the terms used in this application.

[0051] 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 as precursors to form perovskite thin films on the surface of substrates through processes such as spin coating.

[0052] 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.

[0053] 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.

[0054] XRD: It is the abbreviation of X-ray diffraction. It is a technique used to analyze the crystal structure. X-ray diffraction technology is based on the Bragg law of crystals. By measuring the diffraction pattern of X-rays in the crystal, the lattice parameters and crystal structure information of the crystal can be determined.

[0055] PL mapping: full name Photoluminescence mapping, is a photoluminescence-based imaging technology, usually used to study the optical and structural properties of semiconductor materials, optoelectronic devices, perovskite materials, etc. Through PLmapping, high-resolution imaging of the spatial distribution of the material's internal structure, defect distribution, band structure and other properties can be achieved.

[0056] 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:

[0057] The embodiment of the present application provides a perovskite precursor solution, including: a perovskite material, a dual additive and an organic solvent. The perovskite material contains a perovskite precursor, the dual additives are ammonium iodide and potassium acetate, and the organic solvent includes N,N-dimethylformamide and dimethyl sulfoxide. Among them, the dual additive can regulate crystallization and passivate defects. The CH3COO- in potassium acetate can combine with the Pb2+ ions in the perovskite to improve the crystallization quality, promote the nucleation and growth of the perovskite crystal, make the film more uniform and dense, and combine with the NH4+ in the ammonium iodide in the subsequent annealing process to form volatile CH3COONH4. At the same time, the potassium ions in the potassium acetate can combine with the I in the ammonium iodide. - Further KI is formed and the defects are passivated.

[0058] 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.

[0059] The embodiment of the present application provides a perovskite precursor solution, including: a perovskite material and a dual additive;

[0060] 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;

[0061] The dual additives are ammonium iodide and potassium acetate.

[0062] The perovskite precursor solution of the embodiment of the present application includes a perovskite material and a dual additive. The dual additive can regulate crystallization and passivate defects. The CH3COO- in potassium acetate can combine with the Pb2+ ions in the perovskite to improve the crystallization quality, promote the nucleation and growth of the perovskite crystal, make the film more uniform and dense, and combine with the NH4+ in the ammonium iodide in the subsequent annealing process to form volatile CH3COONH4. At the same time, the potassium ions in the potassium acetate can combine with the I in the ammonium iodide. -KI is further formed and defects are passivated. Therefore, the addition of dual additives in the embodiment of the present application can improve the crystallization quality of the perovskite film while passivating defects, thereby more effectively improving device performance.

[0063] In an optional embodiment, the molar concentration ratio of ammonium iodide to potassium acetate is 1: 2-2: 1. Exemplarily, the molar concentration ratio of ammonium iodide to potassium acetate is 1: 2, 2: 3, 3: 4, 1: 1, 4: 3, 3: 2 or 2: 1, etc.

[0064] In the perovskite precursor solution of the embodiment of the present application, ammonium iodide and potassium acetate can work synergistically in the range of 1:2-2:1 molar concentration ratio, effectively passivating perovskite defects and promoting the growth of perovskite crystals. Experiments have shown that within this range, the crystallinity and defect density of the perovskite film are optimally balanced, thereby obtaining the highest perovskite solar cell photoelectric conversion efficiency.

[0065] In an optional embodiment, the molar concentration ratio of the dual additive to the perovskite material is (0%, 6%]. Exemplarily, the molar concentration ratio of the dual additive to the perovskite material is 1%, 2%, 3%, 4%, 5%, or 6%. In the present embodiment, the range of (0%, 6%] is an open interval of 0% to a closed interval of 6%. Experiments have shown that when the molar concentration of the dual additive to the perovskite material is within this range, the crystallinity and defect density of the perovskite film are optimally balanced, thereby obtaining the highest perovskite solar cell photoelectric conversion efficiency.

[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 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 perovskite precursor materials, and has a high boiling point, which can improve the film quality of the film. Dimethyl sulfoxide has a high polarity, can promote the dissolution of perovskite precursor materials, and has a low volatility, which can improve the compactness of the film. Among them, the proportion of organic solvents 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 organic solvents and take necessary protective measures. The optional organic solvents in the embodiments of the present application all have the following characteristics: they can dissolve perovskite precursor materials, have good volatility, 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, 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. The addition of dual additives in the embodiment of the present application can improve the crystallization quality of the perovskite film while passivating defects, thereby more effectively improving device performance.

[0071] In an optional embodiment, the molar concentration ratio of ammonium iodide to potassium acetate is 1:2-2:1. Exemplarily, the molar concentration ratio of ammonium iodide to potassium acetate is 1:2, 2:3, 3:4, 1:1, 4:3, 3:2 or 2:1, etc. In the perovskite precursor solution of the embodiment of the present application, ammonium iodide and potassium acetate can work synergistically in the molar concentration ratio range of 1:2-2:1, effectively passivating perovskite defects while promoting the growth of perovskite crystals. And experiments show that within this range, the crystallinity and defect density of the perovskite film are optimally balanced, thereby obtaining the highest perovskite solar cell photoelectric conversion efficiency.

[0072] In an optional embodiment, the molar concentration ratio of the dual additive to the perovskite material is (0%, 6%). Exemplarily, the molar concentration ratio of the dual additive to the perovskite material is 1%, 2%, 3%, 4%, 5%, or 6%. Experiments have shown that when the molar concentration of the dual additive to the perovskite material is within this range, the crystallinity and defect density of the perovskite film are optimally balanced, thereby obtaining the highest perovskite solar cell photoelectric conversion efficiency.

[0073] In an optional embodiment, the thickness of the perovskite light absorbing layer 14 is 500nm-1.6μm, and illustratively, the thickness of the perovskite light absorbing layer 14 is 500nm, 600nm, 700nm, 800nm, 1μm, 1.2μm, 1.4μm or 1.6μm; the band gap of the perovskite light absorbing layer 14 is 1.61eV-1.79eV, and illustratively, the band gap of the perovskite light absorbing layer 14 is 1.61eV, 1.65eV, 1.70eV, 1.75eV or 1.79eV. The thickness of the perovskite light absorbing layer 14 provided in the embodiment of the present application will effectively affect the light absorption efficiency, carrier transmission efficiency, battery efficiency, etc. of the battery, and the specific value of its thickness needs to be adjusted within the range provided in the present application according to the specific material and battery structure. The band gap of the perovskite light absorbing layer 14 will effectively affect the light absorption range, open circuit voltage and battery efficiency of the battery, and its specific value needs to be adjusted within the range provided in this application according to the solar spectrum and the battery application scenario. And experiments have shown that the thickness range of the perovskite light absorbing layer provided in the embodiment of the present application can enable the battery to obtain the best light absorption efficiency, carrier transfer efficiency, battery efficiency, etc. The band gap range of the perovskite light absorbing layer provided in the embodiment of the present application can enable the battery to obtain the best light absorption range, open circuit voltage and battery efficiency.

[0074] 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. Transparent conductive oxide layers are generally used as electrode materials in photovoltaic devices such as solar cells. The optional materials for the transparent conductive oxide layer provided in this embodiment have excellent transparency and conductivity, and can improve light transmittance and battery collection efficiency.

[0075] 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. 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.

[0076] In an optional embodiment, the electron transport layer 15 includes one or more of SnO2, ZnO, ZrO2, fullerene, and fullerene derivatives. The optional materials provided in this embodiment all have good electron transport properties, which are conducive to the migration and transmission of electrons in the material, thereby reducing the recombination of electrons and holes and improving the photoelectric conversion efficiency.

[0077] 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 the transmission efficiency of electrons, thereby enhancing the electrical performance of the solar cell device.

[0078] The present invention provides a method for preparing a perovskite solar cell. Figure 2 , the preparation method of the perovskite solar cell comprises:

[0079] S10: providing a conductive substrate.

[0080] S11: depositing a transparent conductive oxide layer on the surface of the conductive substrate.

[0081] S12: forming a hole transport layer on the surface of the transparent conductive oxide layer.

[0082] S13: forming a perovskite light absorbing layer on the surface of the hole transport layer.

[0083] S14: forming an electron transport layer on the surface of the perovskite light absorbing layer.

[0084] S15: forming a back electrode on the surface of the electron transport layer.

[0085] Wherein, the perovskite light absorbing layer is prepared from a perovskite precursor solution according to any one of the above embodiments.

[0086] In this embodiment, a method for preparing a (wide bandgap) perovskite solar cell specifically includes the following details:

[0087] (1) treating the ITO conductive substrate with UV ozone for 15 minutes;

[0088] (2) A 15 nm NiOx hole transport layer was prepared by magnetron sputtering, and NiOx was further modified by 2PACz;

[0089] (3) A perovskite precursor solution with a composition of FA0.8Cs0.2PbI1.8Br1.2 was prepared using CsI, FAI, PbI2, and PbBr2, and doped with NH4I and CH3COOK as dual additives;

[0090] (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;

[0091] 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;

[0092] (6) A 150 nm thick Ag back electrode was deposited by thermal evaporation.

[0093] In an optional embodiment, the method for forming a hole transport layer includes: magnetron sputtering nickel oxide on a transparent conductive oxide on the surface of a conductive substrate, the thickness of the nickel oxide being 5nm-20nm. In this embodiment, the magnetron sputtering deposition technology refers to bombarding a nickel oxide target with high-energy ions under vacuum conditions, and the sputtered atoms are deposited on a 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 the nickel oxide will 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, and the hole transport layer within this thickness range has the best performance. Among them, the nickel oxide used to form the hole transport layer has good conductivity and hole transport ability, and can effectively extract holes from the perovskite light absorption layer.

[0094] In an optional embodiment, forming a perovskite light absorbing layer includes:

[0095] Spin coating the precursor solution on the surface of the hole transport layer;

[0096] An antisolvent is added to the precursor solution during spin coating;

[0097] The spin-coated perovskite film is annealed.

[0098] In this embodiment, the method of forming the perovskite light absorbing layer includes but is not limited to an anti-solvent method, a gas quenching method, a spin coating method, a coating method, and a doctor blade coating method.

[0099] 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.

[0100] In an optional embodiment, the anti-solvent includes any one of anisole, chlorobenzene, and diethyl carbonate. In this embodiment, the anti-solvent is mixed with the solvent in the precursor solution to reduce the volatilization rate of the solvent, thereby promoting the growth of perovskite crystals and controlling the morphology of the perovskite film.

[0101] 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.

[0102] In an optional embodiment, the electron transport layer includes a fullerene layer and a barrier layer; wherein, forming the electron transport layer includes: after forming the fullerene layer on the surface of the perovskite light absorbing layer, forming a barrier layer 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, and the barrier layer prevents electrons from flowing back from the electron transport layer to the perovskite light absorbing layer, thereby increasing the open circuit voltage 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.

[0103] 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 prevent direct contact between electrons in the perovskite light absorption layer and materials with low transmission rates (such as metal electrodes), thereby preventing uncontrolled transmission of electrons and adverse reactions between electrons and impurities, and helping to improve the performance and stability of the device.

[0104] 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.

[0105] [Example 1]

[0106] like Figure 1 As shown, the specific structure of a perovskite solar cell is:

[0107] 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.

[0108] like Figure 2As shown, the specific preparation process of a perovskite solar cell is as follows:

[0109] S10: providing a conductive substrate;

[0110] S11: depositing a transparent conductive oxide layer on the surface of the conductive substrate;

[0111] S12: forming a hole transport layer on the surface of the transparent conductive oxide layer;

[0112] S13: forming a perovskite light absorption layer on the surface of the hole transport layer;

[0113] S14: forming an electron transport layer on the surface of the perovskite light absorbing layer;

[0114] S15: forming a back electrode on the surface of the electron transport layer;

[0115] 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:

[0116] S101: The perovskite material, the dual additives (ammonium iodide and potassium acetate), 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 ammonium iodide and potassium acetate is 1:1; and the molar concentration ratio of the dual additives to the perovskite material is 3%.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] S106: performing annealing treatment on the obtained perovskite film at a temperature of 120° C. for 20 minutes.

[0122] 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.

[0123] S108: Using a thermal evaporation method, a 150 nm Ag back electrode is deposited on the surface of the electron transport layer.

[0124] [Example 2]

[0125] The perovskite solar cell of Example 2 is prepared by referring to the preparation method of Example 1, except that S101 of Example 2 is: the perovskite material, the double additives (ammonium iodide and potassium acetate), and the organic solvent (N,N-dimethylformamide and dimethyl sulfoxide) are evenly mixed to prepare a perovskite precursor solution; wherein the perovskite material is an ABX3 structure; A is a monovalent cation, including one of cesium (Cs), rubidium (Rb), methylamine (CH3NH3), and guanidine (CH2(NH2)2) or a mixture of several monovalent cations; B is a divalent cation, including one or a mixture of several divalent cations of lead (Pb), copper (Cu), zinc (Zn), gallium (Ga), tin (Sn), and calcium (Ca); X is a monovalent anion, including one or a mixture of several monovalent anions of iodine (I), bromine (Br), chlorine (Cl), fluorine (F), and thiocyanate ion (SCN); the molar concentration ratio of ammonium iodide to potassium acetate is 1:2; the molar concentration ratio of the dual additive to the perovskite material is 1%.

[0126] [Example 3]

[0127] 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 dual additives (ammonium iodide and potassium acetate), 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 ammonium iodide to potassium acetate was 2:1; and the molar concentration ratio of the dual additive to the perovskite material was 1%.

[0128] [Comparative Example 1]

[0129] 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).

[0130] 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, short circuit current density Jsc of the corresponding battery devices, and the test results are shown in Table 1.

[0131] Table 1 Performance test results of perovskite solar cells of Examples 1-3 and Comparative Example 1

[0132]

[0133] In addition, the present application also provides XRD patterns of the perovskite films prepared from the precursor solutions obtained in Comparative Example 1 (Control) and Example 1 (Target). Figure 3 As shown. In addition, the present application also provides PL mapping (photoluminescence mapping) images of the perovskite film prepared from the precursor solution obtained in Example 1 (left) and Comparative Example 1 (right). For details, please refer to Figure 4 .

[0134] It can be seen from Table 1 that 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 compared with Comparative Example 1. This indicates that the perovskite films of Examples 1-3 of the present application have stronger perovskite crystals, tight film texture, and better quality.

[0135] In summary, the embodiment of the present application prepares a perovskite precursor solution using perovskite materials, ammonium iodide, potassium acetate 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 also has low volatility and can improve the compactness of the film. The dual additives of ammonium iodide and potassium acetate improve the crystallization quality of the perovskite film while passivating defects, thereby more effectively improving device performance.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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 dual 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 dual additives are ammonium iodide and potassium acetate.

2. The perovskite precursor solution according to claim 1, characterized in that The molar concentration ratio of the ammonium iodide to the potassium acetate is 1:2-2:

1.

3. The perovskite precursor solution according to claim 1, characterized in that The molar concentration ratio of the dual additives to the perovskite material is (0%, 6%).

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 further includes an organic solvent, 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 500nm-1.6μm, and the band gap of the perovskite light absorbing layer is 1.61eV-1.79eV.

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 a perovskite light absorbing layer on the surface of the hole transport 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 or 10, characterized in that: The anti-solvent includes any one 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 according to 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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