Perovskite precursor solution, preparation method thereof, perovskite solar cell and photovoltaic system

Abstract

The embodiment of the invention provides a perovskite precursor solution and a preparation method thereof, a perovskite solar cell and a photovoltaic system, and relates to the technical field of perovskite solar cells. The perovskite precursor solution comprises a perovskite material, an additive and an organic solvent; the additive includes a volatile solid acid. Volatile solid acid is added into a perovskite precursor solution, functional groups such as carboxyl, sulfydryl, hydroxyl and amino in the volatile solid acid can generate relatively strong interaction with FA < + > and PbI2 in a perovskite material, the crystallization speed of perovskite is delayed, the defects of perovskite crystals are passivated, meanwhile, the grain size of the perovskite crystals is increased, and the performance of the perovskite material is improved. Therefore, the large-area perovskite light absorption layer which is high in coverage rate, flat, compact and free of pinholes is prepared. And the boiling point of the volatile solid acid is relatively low, so that after annealing treatment, the prepared perovskite light absorption layer has no residual phase except the perovskite, and the film forming quality and the long-term stability of the perovskite light absorption layer can be improved.

Description

Technical Field

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

[0002] Perovskite material originally refers to an inorganic material calcium titanate (CaTiO 3 ) and was later used to refer to minerals with ABX 3 A family of compounds with a similar structure. Perovskite materials can be used to prepare perovskite solar cells (PSCs). The research on perovskite solar cells began in 2009. Perovskite solar cells have attracted widespread attention due to their advantages such as lower cost, low-temperature processing, and high power conversion efficiency. Compared with traditional silicon-based solar cells, the advantages of perovskite solar cells are their higher photoelectric conversion efficiency, low production cost, and solution processability. Therefore, perovskite solar cells have great potential for large-scale production.

[0003] Scraping, slit extrusion coating and other processes are suitable for the preparation of large-area perovskite solar cells. However, when using scraping, slit extrusion coating and other processes to prepare large-area perovskite solar cells, they face more complex fluid dynamics processes, and it is difficult to effectively control the nucleation and crystallization process of the perovskite film. In addition, some volatilization components are not completely volatilized, resulting in poor coverage of the prepared perovskite film, rough surface, more surface defects and poor stability.

[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 present application provides a perovskite precursor solution and a preparation method thereof, a perovskite solar cell and a photovoltaic system to solve or alleviate the above-mentioned technical problems. The present application adds a volatile solid acid as an additive to the perovskite precursor solution. The functional groups such as carboxyl, thiol, hydroxyl and amino in the volatile solid acid can react with the FA in the perovskite material. + and PbI 2 A relatively strong interaction is generated between the two, which slows down the crystallization rate of the perovskite, passivates the defects of the perovskite crystals, and at the same time increases the grain size of the perovskite crystals, improving the quality of the prepared perovskite light-absorbing layer, thereby preparing a large-area perovskite light-absorbing layer with high coverage, flatness, density, and zero pinholes; and because the boiling point of the volatile solid acid is relatively low, after annealing treatment, there is no excess phase remaining in the prepared perovskite light-absorbing layer except for the perovskite, which is beneficial to improving the film-forming quality and long-term stability of the perovskite light-absorbing layer.

[0006] To achieve the above purpose, this application adopts the following technical solutions: A perovskite precursor solution, comprising: a perovskite material, an additive, and an organic solvent; Wherein, the additive comprises a volatile solid acid.

[0007] In some embodiments, the volatile solid acid includes one or more of glycolic acid, thioglycolic acid, and glycine.

[0008] In some embodiments, the structure of the perovskite material is FA a MA b Cs c Pb(I m Br n ) 3 .

[0009] In some embodiments, the organic solvent includes 2-mercaptoethanol and dimethyl sulfoxide.

[0010] In some embodiments, the volume ratio of the 2-mercaptoethanol to the dimethyl sulfoxide is 8:1 to 15:1.

[0011] The embodiment of the present application also provides a method for preparing a perovskite precursor solution, wherein the perovskite precursor solution comprises: a perovskite material, an additive, and an organic solvent; the additive comprises a volatile solid acid; the volatile solid acid comprises: one or more of glycolic acid, thioglycolic acid, and glycine; Dissolving the perovskite material in the organic solvent and mixing them uniformly to prepare a perovskite solution; adding the additive to the perovskite solution and mixing them uniformly to obtain the perovskite precursor solution; Wherein, in the perovskite solution, the amount of the additive added satisfies at least one of the following characteristics: (1) When the additive is glycolic acid, the amount of the additive added to each milliliter of the perovskite solution is 1-5 mg; (2) When the additive is thioglycolic acid, the amount of the additive added to each milliliter of the perovskite solution is 0.5-2.5 μL; (3) When the additive is glycine, the amount of the additive added to each milliliter of the perovskite solution is 0.5-3.5 mg.

[0012] The embodiment of the present application also provides a perovskite solar cell, including a perovskite light absorbing layer; Wherein, the perovskite light absorbing layer is formed by the above-mentioned perovskite precursor solution; Alternatively, the perovskite light-absorbing layer is formed by a perovskite precursor solution prepared by the above preparation method.

[0013] In some of the embodiments, the perovskite solar cell is a single-junction perovskite solar cell or a silicon-based / perovskite stacked solar cell; the method for preparing the perovskite light-absorbing layer comprises: coating the perovskite precursor solution on a substrate by a slit extrusion coating method or a doctor blade coating method, and then annealing at 100-120° C. for 20-30 minutes to form the perovskite light-absorbing layer.

[0014] In some embodiments, the method for preparing the perovskite light absorbing layer satisfies at least one of the following characteristics: (1) When the perovskite precursor solution is coated on the substrate by a slit extrusion coating method or a blade coating method, the temperature and relative humidity of the environment meet the following conditions: RH = 20 ± 5%, T = 22 ± 5 °C; (2) When the perovskite precursor solution is coated on the substrate by a slit extrusion coating method or a doctor blade coating method, the temperature of the substrate is controlled at 73-77° C.; (3) The coating speed of the perovskite precursor solution is controlled at 28-32 mm / s.

[0015] An embodiment of the present application also provides a photovoltaic system, comprising the above-mentioned perovskite solar cell.

[0016] The above technical solution adopted in the embodiment of the present application may have the following advantages: Volatile solid acid is added as an additive to the perovskite precursor solution. The functional groups such as carboxyl, thiol, hydroxyl, and amino in the volatile solid acid can react with the FA in the perovskite material. + and PbI 2 A relatively strong interaction is generated between the two, which slows down the crystallization rate of the perovskite, passivates the defects of the perovskite crystals, and at the same time increases the grain size of the perovskite crystals, improving the quality of the prepared perovskite light-absorbing layer, thereby preparing a large-area perovskite light-absorbing layer with high coverage, flatness, density, and zero pinholes; and because the boiling point of the volatile solid acid is relatively low, after annealing treatment, there is no excess phase remaining in the prepared perovskite light-absorbing layer except for the perovskite, which is beneficial to improving the film-forming quality and long-term stability of the perovskite light-absorbing layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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.

[0018] Figure 1 is a schematic structural diagram of a single-junction perovskite solar cell provided in an embodiment of the present application; Figure 2is a schematic structural diagram of a silicon-based / perovskite tandem solar cell provided in an embodiment of the present application; Description of reference numerals: 11. first transparent conductive substrate; 12. first hole transport layer; 13. first perovskite light absorption layer; 14. first electron transport layer; 15. first hole blocking layer; 16. metal electrode; 22. Second transparent conductive substrate; 23. First amorphous silicon passivation layer; 24. Crystalline silicon bottom cell absorption layer; 25. Second amorphous silicon passivation layer; 26. Tunneling layer; 27. Second hole transport layer; 28. Second perovskite light absorption layer; 29. ​​Second electron transport layer; 30. Second hole blocking layer; 31. Transparent electrode layer; 32. Silver grid line electrode. DETAILED DESCRIPTION

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to an integer in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed in the present application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for broadly including quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0024] The present application aims to provide a perovskite precursor solution and a preparation method thereof, a perovskite solar cell and a photovoltaic system. A volatile solid acid is added as an additive to the perovskite precursor solution. The functional groups such as carboxyl, thiol, hydroxyl and amino in the volatile solid acid can react with the FA in the perovskite material. + and PbI 2A relatively strong interaction is generated between the two, which slows down the crystallization rate of the perovskite, passivates the defects of the perovskite crystals, and at the same time increases the grain size of the perovskite crystals, improving the quality of the prepared perovskite light-absorbing layer, thereby preparing a large-area perovskite light-absorbing layer with high coverage, flatness, density, and zero pinholes; and because the boiling point of the volatile solid acid is relatively low, after annealing treatment, there is no excess phase remaining in the prepared perovskite light-absorbing layer except for the perovskite, which is beneficial to improving the film-forming quality and long-term stability of the perovskite light-absorbing layer.

[0025] Below, exemplary embodiments of 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.

[0026] The embodiment of the present application provides a perovskite precursor solution, including: a perovskite material, an additive, and an organic solvent; Wherein, the additive comprises a volatile solid acid.

[0027] In the embodiments of the present application, volatile solid acids (VSAs) refer to solid acidic substances that can volatilize under certain conditions. Volatile solid acids usually exist in solid form and can be converted into gaseous or dissolved states under certain conditions (such as heating or in a specific solvent).

[0028] In the embodiment of the present application, the perovskite material is ABX 3 structure; A is a monovalent cation; B is a divalent cation; X is a monovalent anion. More specifically, A includes but is not limited to cesium (Cs), rubidium (Rb), methylamine (CH 3 NH 3 ), carboxamidino (CH 2 (NH 2 ) 2 ) is a mixture of one or more monovalent cations selected from lead (Pb), copper (Cu), zinc (Zn), gallium (Ga), tin (Sn), and calcium (Ca); X is a mixture of one or more monovalent anions selected from iodine (I), bromine (Br), chlorine (Cl), fluorine (F), and thiocyanate ion (SCN).

[0029] In an embodiment of the present application, the organic solvent includes one or more of N-methylpyrrolidone (NMP), 2-mercaptoethanol (2-ME), dimethyl sulfoxide (DMSO), diphenyl sulfoxide (DPSO), dimethylformamide (DMF), acetonitrile (ACN), dimethylacetamide (DMAc), N,N'-dimethylpropylene urea (DMPU), and 1,4-butyrolactone.

[0030] In the embodiment of the present application, a volatile solid acid is added as an additive to the perovskite precursor solution. The functional groups such as carboxyl, thiol, hydroxyl, and amino groups in the volatile solid acid can react with the FA in the perovskite material. + and PbI 2 A relatively strong interaction is generated between the two, which slows down the crystallization rate of the perovskite, passivates the defects of the perovskite crystals, and at the same time increases the grain size of the perovskite crystals, improving the quality of the prepared perovskite light-absorbing layer, thereby preparing a large-area perovskite light-absorbing layer with high coverage, flatness, density, and zero pinholes; and because the boiling point of the volatile solid acid is relatively low, after annealing treatment, there is no excess phase residue in the prepared perovskite light-absorbing layer except for the perovskite, which is beneficial to improving the film-forming quality and long-term stability of the perovskite light-absorbing layer, thereby further improving the photoelectric conversion rate of the perovskite solar cell.

[0031] In an optional embodiment, the volatile solid acid includes one or more of glycolic acid, thioglycolic acid, and glycine.

[0032] In the examples of the present application, the types of volatile solid acids are optimized, and the functional groups such as carboxyl, thiol, hydroxyl, and amino groups in the volatile solid acids can react with the FA in the perovskite material. + and PbI 2 A relatively strong interaction is generated between them, which further slows down the crystallization rate of the perovskite, passivates the defects of the perovskite crystals, and increases the grain size of the perovskite crystals, thereby further improving the quality of the prepared perovskite light-absorbing layer.

[0033] In an optional embodiment, the structure of the perovskite material is FA a MA b Cs c Pb(I m Br n ) 3 In the embodiment of the present application, a, b, c, m, and n satisfy: a+b+c=1, m+n=1, and c<0.3. Preferably, a, b, c, m, and n satisfy: a+b+c=1, m+n=1, a:(b+c)=1:(0~0.25), c=0.1~0.3, and c<0.3.

[0034] In the embodiment of the present application, the structure of the perovskite material is optimized to help improve the carboxyl, thiol, hydroxyl, amino and other functional groups in the volatile solid acid to react with the FA in the perovskite material. + and PbI 2 The interaction between them slows down the crystallization rate of perovskite and is beneficial to passivating the defects of perovskite crystals, thereby further improving the quality of the prepared perovskite light-absorbing layer.

[0035] In an optional embodiment, the organic solvent includes 2-mercaptoethanol and dimethyl sulfoxide.

[0036] In the embodiment of the present application, 2-mercaptoethanol and dimethyl sulfoxide can be mixed in any proportion. By optimizing the composition of the organic solvent, the dissolution effect of the perovskite material and the volatile solid acid is better, thereby further improving the quality of the prepared perovskite light-absorbing layer, which is beneficial to improving the photoelectric conversion rate of the perovskite solar cell.

[0037] In an optional embodiment, the volume ratio of the 2-mercaptoethanol to the dimethyl sulfoxide is 8:1 to 15:1.

[0038] In the embodiment of the present application, the mixing ratio of 2-mercaptoethanol and dimethyl sulfoxide is optimized, and the dissolution effect of the perovskite material and the volatile solid acid is better, thereby further improving the quality of the prepared perovskite light-absorbing layer, which is beneficial to improving the photoelectric conversion rate of the perovskite solar cell.

[0039] The embodiment of the present application also provides a method for preparing a perovskite precursor solution, wherein the perovskite precursor solution comprises: a perovskite material, an additive, and an organic solvent; the additive comprises a volatile solid acid; the volatile solid acid comprises: one or more of glycolic acid, thioglycolic acid, and glycine; Dissolving the perovskite material in the organic solvent and mixing them uniformly to prepare a perovskite solution; adding the additive to the perovskite solution and mixing them uniformly to obtain the perovskite precursor solution; Wherein, in the perovskite solution, the amount of the additive added satisfies at least one of the following characteristics: (1) When the additive is glycolic acid, the amount of the additive added per milliliter of the perovskite solution is 1 to 5 mg (for example, 1 mg, 2 mg, 3 mg, 4 mg, 5 mg); (2) When the additive is thioglycolic acid, the amount of the additive added per milliliter of the perovskite solution is 0.5 to 2.5 μL (for example, 0.5 μL, 1.0 μL, 1.5 μL, 2.0 μL, 2.5 μL); (3) When the additive is glycine, the amount of the additive added per milliliter of the perovskite solution is 0.5-3.5 mg (for example, 0.5 mg, 1 mg, 1.5 mg, 2 mg, 2.5 mg, 3 mg, 3.5 mg).

[0040] In the embodiment of the present application, the amount of additives added is optimized to help increase the carboxyl, thiol, hydroxyl, amino and other functional groups in the volatile solid acid to react with the FA in the perovskite material. + and PbI 2The interaction between them slows down the crystallization rate of perovskite and is beneficial to passivating the defects of perovskite crystals, thereby further improving the quality of the prepared perovskite light-absorbing layer.

[0041] The embodiment of the present application also provides a perovskite solar cell, including a perovskite light absorbing layer; Wherein, the perovskite light absorbing layer is formed by the above-mentioned perovskite precursor solution; Alternatively, the perovskite light-absorbing layer is formed by a perovskite precursor solution prepared by the above preparation method.

[0042] In the embodiment of the present application, the perovskite light absorbing layer is formed by the above-mentioned perovskite precursor solution. Since a volatile solid acid is added as an additive to the perovskite precursor solution, the functional groups such as carboxyl, thiol, hydroxyl, and amino in the volatile solid acid can react with the FA in the perovskite material. + and PbI 2 A relatively strong interaction is generated between the two, which slows down the crystallization speed of perovskite, passivates the defects of perovskite crystals, and increases the grain size of perovskite crystals, improving the quality of the prepared perovskite light-absorbing layer, thereby being able to prepare a large-area perovskite light-absorbing layer with high coverage, flatness, density, and zero pinholes. This is beneficial to improving the photoelectric conversion rate of perovskite solar cells.

[0043] In an optional embodiment, the perovskite solar cell is a single-junction perovskite solar cell or a silicon-based / perovskite stacked solar cell; the preparation method of the perovskite light-absorbing layer includes: coating the perovskite precursor solution on the substrate by a slit extrusion coating method or a blade coating method, and then annealing at 100-120°C (for example, 100°C, 105°C, 110°C, 115°C, 120°C) for 20-30min (for example, 20min, 21min, 22min, 23min, 24min, 25min, 26min, 27min, 28min, 29min, 30min) to form the perovskite light-absorbing layer. It should be noted that other cells containing a perovskite layer may also be included.

[0044] In the present application embodiment, Figure 1 As shown, the single-junction perovskite solar cell comprises: a first transparent conductive substrate (ITO), a first hole transport layer (NiO x )、the first perovskite light absorbing layer(Perovskite)、the first electron transport layer(C 60 ), the first hole blocking layer (PCB) and the metal electrode (Ag). Figure 2As shown, the silicon-based / perovskite stacked solar cell includes a second transparent conductive substrate (ITO), a first amorphous silicon passivation layer (a-Si:H(p) and a-Si:H(i) stacked in sequence), a crystalline silicon bottom cell absorption layer (c-Si), a second amorphous silicon passivation layer (a-Si:H(i) and a-Si:H(n) stacked in sequence), a tunneling layer (ITO), a second hole transport layer (NiO x ), the second perovskite light absorbing layer (Perovskite), the second electron transport layer (LiF and C stacked in sequence) 60 ), the second hole blocking layer (SnO 2 ), transparent electrode layer (ITO), silver grid electrode (Ag). Other layers can also be set according to actual needs.

[0045] The following is an exemplary introduction to some layers.

[0046] Metal electrode: gold, palladium, silver, titanium, chromium, nickel, aluminum, copper, indium tin oxide (ITO), indium zinc oxide (IZO), etc. The thickness of the back electrode can be 60-100nm (for example, 60nm, 80nm, 100nm).

[0047] Electron transport layer: Titanium oxide (TiO 2 ), tin oxide (SnO 2 )、ZnO、Fullerene(C 60 ), graphene, fullerene derivatives (PCBM) and other one or more n-type semiconductor materials, the electron transport layer can be prepared by deposition methods including but not limited to electron beam evaporation, thermal evaporation, magnetron sputtering, atomic layer deposition, spin coating, scraping and the like. The thickness of the electron transport layer can be 20-40nm (for example, 20nm, 30nm, 40nm).

[0048] Perovskite light absorbing layer: formed by the above-mentioned perovskite precursor solution. The preparation method of the perovskite light absorbing layer is one or more of spin coating, scraper coating, evaporation, printing, spraying, spray pyrolysis, and slit coating; that is, the perovskite light absorbing layer is formed on the upper surface of the electron transport layer by spin coating, scraper coating, etc.; different preparation methods will also have some influence on the crystallization of the perovskite light absorbing layer, and the corresponding preparation method can be selected according to actual needs. When the perovskite light absorbing layer is obtained by coating the upper surface of the electron transport layer by one-step spin coating or slit coating, the coating speed can be 4000-5000 rpm / min (for example, 4000 rpm / min, 4500 rpm / min, 5000 rpm / min), and the coating time can be 30-40s (for example, 30s, 35s, 40s). The band gap of the perovskite light absorbing layer can be 1.66-3.0eV.

[0049] Hole transport layer: nickel oxide (NiO), cuprous oxide (Cu 2 O), molybdenum oxide (MoO 3 ), copper iodide (CuI) and other inorganic transport materials, and redox graphene, poly [bis (4-phenyl) (2,4,6-trimethylphenyl) amine] (PTAA, poly (triaryl amine)), 2,2',7,7'-tetrakis [N,N-di (4-methoxyphenyl) amino] -9,9'-spirobifluorene (Spiro-OMeTAD), poly 3,4-ethylenedioxythiophene: polystyrene sulfonate (PEDOT:PSS), poly [bis (4-phenyl) (4-butylphenyl) amine] (Ploy-TPD), [2- (9H-carbazole-9-yl) ethyl] phosphonic acid, [2- (3,6-dimethoxy-9H-carbazole-9-yl) ethyl] phosphonic acid and other one or more organic p-type semiconductor materials. The thickness of the hole transport layer can be 20-40nm (for example, 20nm, 30nm, 40nm).

[0050] Transparent conductive substrate, transparent electrode layer: Indium tin oxide (ITO) substrate, fluorine-doped tin oxide (FTO) substrate, indium zinc oxide (IZO) substrate, etc. The thickness of the transparent conductive glass layer can be 60-200nm (for example, 60nm, 80nm, 100nm, 120nm, 140nm, 160nm, 180nm, 200nm).

[0051] In the embodiments of the present application, the annealing process of the perovskite light absorbing layer is optimized. After the annealing treatment, no excess phases other than the perovskite remain, which can improve the quality of the prepared perovskite light absorbing layer. Thus, a large-area perovskite light absorbing layer with high coverage, flatness, density and zero pinholes can be prepared, which is beneficial to improving the photoelectric conversion rate of perovskite solar cells.

[0052] In an optional embodiment, the method for preparing the perovskite light absorbing layer satisfies at least one of the following characteristics: (1) When the perovskite precursor solution is coated on the substrate by a slit extrusion coating method or a blade coating method, the temperature and relative humidity of the environment meet the following conditions: RH = 20 ± 5%, T = 22 ± 5 °C; (2) When the perovskite precursor solution is coated on the substrate by a slit extrusion coating method or a doctor blade coating method, the temperature of the substrate is controlled at 73-77° C.; (3) The coating speed of the perovskite precursor solution is controlled at 28-32 mm / s.

[0053] In the embodiments of the present application, the coating process of the perovskite light absorbing layer is optimized, which can improve the coating effect of the perovskite precursor solution, and further improve the quality of the prepared perovskite light absorbing layer, thereby being able to prepare a large-area perovskite light absorbing layer with high coverage, flatness, density, and zero pinholes, which is beneficial to improving the photoelectric conversion rate of perovskite solar cells.

[0054] 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.

[0055] Example 1 A single-junction perovskite solar cell, such as Figure 1 As shown, it includes: a first transparent conductive substrate (ITO) 11, a first hole transport layer (NiO x ) 12. The first perovskite light absorption layer (Perovskite) 13. The first electron transport layer (C 60 )14, a first hole blocking layer (PCB) 15 and a metal electrode (Ag) 16.

[0056] The specific preparation process of the single-junction perovskite solar cell is as follows: Step S1: providing a cleaned transparent conductive glass layer, wherein the transparent conductive glass layer is a first transparent conductive substrate (ITO) 11, and has a thickness of 80 nm; Step S2: depositing a layer of nickel and oxygen compound (NiO x ) as the first hole transport layer (NiO x ) 12, thickness is 40nm; Step S3: dissolving the perovskite material in an organic solvent to prepare a perovskite solution; wherein the structure of the perovskite material is Cs 0.05 MA 0.15 FA 0.8 Pb(I 0.75 Br 0.25 ) 3 The specific formula of each component is: CsI (19.5 mg); MABr (25.1 mg); FAI (206.4 mg); PbI 2 (484.1 mg); PbBr 2 (165.1 mg); dissolving the above perovskite raw material in 1 mL of a mixed solvent of 2-mercaptoethanol (2-ME) and dimethyl sulfoxide (DMSO), with the solvent volume ratio being 2ME:DMSO=9:1, to obtain a perovskite solution; the concentration of the perovskite solution is 1.5 M (i.e., 1.5 moles of perovskite material per liter of solution); Step S4: The additive is glycolic acid (GA), 3 mg of GA is added to 1 mL of the perovskite solution, and then the mixed solution is heated and stirred at 45° C. for 6 h on a heated magnetic stirring table to obtain a perovskite precursor solution; Step S5: The above perovskite precursor solution is placed in a temperature and humidity controlled environment (RH=20%, T=22°C), while the substrate temperature is controlled at 75°C and the coating speed is 30 mm / s, and coated on the first hole transport layer (NiO x ) 12 prepares a perovskite layer, and then anneals at 110° C. for 20 min to form a first perovskite light absorbing layer (Perovskite) 13. The thickness of the first perovskite light absorbing layer (Perovskite) 13 is 600 nm; Step S6: Using a thermal evaporation film deposition apparatus to deposit a layer of fullerene (C 60 ) as the first electron transport layer (C 60 )14, Fullerene (C 60 ) layer thickness is 25nm; then the fullerene (C 60 ) layer as a first hole blocking layer (PCB) 15, and the thickness of the BCP layer is 20 nm; Step S7: using a thermal evaporation method, a layer of metallic silver is plated on the first hole blocking layer (PCB) 15 as an electrode to form a metal electrode (Ag) 16, and the thickness of the metal electrode (Ag) 16 is 80 nm; a single-junction perovskite solar cell (device size is 105 mm×105 mm) is prepared.

[0057] Example 2-Example 8 The single-junction perovskite solar cells of Examples 2 to 8 were prepared by referring to the preparation method of Example 1, the only difference being that the formulas of the prepared perovskite precursor solutions were different. The formulas of the perovskite precursor solutions in Examples 2 to 8 are shown in Table 1.

[0058] Example 9 The single-junction perovskite solar cell of Example 9 was prepared by referring to the preparation method of Example 1, except that, in step S5 of Example 9, the perovskite precursor solution was placed in a temperature and humidity controlled environment (RH=10%, T=12°C), while the substrate temperature was controlled at 75°C and the coating speed was 30 mm / s, and coated on the first hole transport layer (NiO x) 12 prepares a perovskite layer, and then annealing at 110° C. for 20 minutes to form a first perovskite light absorbing layer (Perovskite) 13. The thickness of the first perovskite light absorbing layer (Perovskite) 13 is 600 nm.

[0059] Example 10 The single-junction perovskite solar cell of Example 10 was prepared by referring to the preparation method of Example 1, except that, in step S5 of Example 10, the perovskite precursor solution was placed in a temperature and humidity controlled environment (RH=30%, T=30°C), while the substrate temperature was controlled at 75°C and the coating speed was 30 mm / s, and coated on the first hole transport layer (NiO x ) 12 prepares a perovskite layer, and then annealing at 110° C. for 20 minutes to form a first perovskite light absorbing layer (Perovskite) 13. The thickness of the first perovskite light absorbing layer (Perovskite) 13 is 600 nm.

[0060] Embodiment 11 The single-junction perovskite solar cell of Example 11 was prepared by referring to the preparation method of Example 1, except that, in step S5 of Example 11, the perovskite precursor solution was placed in a temperature and humidity controlled environment (RH=20%, T=22°C), while the substrate temperature was controlled at 75°C and the coating speed was 30 mm / s, and coated on the first hole transport layer (NiO x ) 12 prepares a perovskite layer, and then annealing at 90° C. for 20 minutes to form a first perovskite light absorbing layer (Perovskite) 13. The thickness of the first perovskite light absorbing layer (Perovskite) 13 is 600 nm.

[0061] Example 12 The single-junction perovskite solar cell of Example 12 was prepared by referring to the preparation method of Example 1, except that, in step S5 of Example 12, the perovskite precursor solution was placed in a temperature and humidity controlled environment (RH=20%, T=22°C), while the substrate temperature was controlled at 75°C and the coating speed was 30 mm / s, and coated on the first hole transport layer (NiO x ) 12 prepares a perovskite layer, and then annealing at 130° C. for 20 minutes to form a first perovskite light absorbing layer (Perovskite) 13. The thickness of the first perovskite light absorbing layer (Perovskite) 13 is 600 nm.

[0062] Example 13 The single-junction perovskite solar cell of Example 13 was prepared by referring to the preparation method of Example 1, except that, in step S5 of Example 13, the perovskite precursor solution was placed in a temperature and humidity controlled environment (RH=20%, T=22°C), while the substrate temperature was controlled at 50°C and the coating speed was 30 mm / s, and coated on the first hole transport layer (NiO x ) 12 prepares a perovskite layer, and then annealing at 110° C. for 20 minutes to form a first perovskite light absorbing layer (Perovskite) 13. The thickness of the first perovskite light absorbing layer (Perovskite) 13 is 600 nm.

[0063] Embodiment 14 The single-junction perovskite solar cell of Example 14 was prepared by referring to the preparation method of Example 1, except that, in step S5 of Example 14, the perovskite precursor solution was placed in a temperature and humidity controlled environment (RH=20%, T=22°C), while the substrate temperature was controlled at 80°C and the coating speed was 30 mm / s, and coated on the first hole transport layer (NiO x ) 12 prepares a perovskite layer, and then annealing at 110° C. for 20 minutes to form a first perovskite light absorbing layer (Perovskite) 13. The thickness of the first perovskite light absorbing layer (Perovskite) 13 is 600 nm.

[0064] Embodiment 15 The single-junction perovskite solar cell of Example 15 was prepared by referring to the preparation method of Example 1, except that, in step S5 of Example 15, the perovskite precursor solution was placed in a temperature and humidity controlled environment (RH=20%, T=22°C), while the substrate temperature was controlled at 75°C and the coating speed was 25 mm / s, and coated on the first hole transport layer (NiO x ) 12 prepares a perovskite layer, and then annealing at 110° C. for 20 minutes to form a first perovskite light absorbing layer (Perovskite) 13. The thickness of the first perovskite light absorbing layer (Perovskite) 13 is 600 nm.

[0065] Example 16 The single-junction perovskite solar cell of Example 16 was prepared by referring to the preparation method of Example 1, except that, in step S5 of Example 16, the perovskite precursor solution was placed in a temperature and humidity controlled environment (RH=20%, T=22°C), while the substrate temperature was controlled at 75°C and the coating speed was 35 mm / s, and coated on the first hole transport layer (NiO x) 12 prepares a perovskite layer, and then annealing at 110° C. for 20 minutes to form a first perovskite light absorbing layer (Perovskite) 13. The thickness of the first perovskite light absorbing layer (Perovskite) 13 is 600 nm.

[0066] Embodiment 17 A silicon-based / perovskite tandem solar cell, such as Figure 2 As shown, it includes: a second transparent conductive substrate (ITO) 22 stacked in sequence, a first amorphous silicon passivation layer (a-Si:H(p) and a-Si:H(i) stacked in sequence) 23, a crystalline silicon bottom cell absorption layer (c-Si) 24, a second amorphous silicon passivation layer (a-Si:H(i) and a-Si:H(n) stacked in sequence) 25, a tunneling layer (ITO) 26, a second hole transport layer (NiO x ) 27. Second perovskite light absorption layer (Perovskite) 28. Second electron transport layer (LiF and C stacked in sequence) 60 )29, the second hole blocking layer (SnO 2 ) 30, transparent electrode layer (ITO) 31, silver grid line electrode (Ag) 32.

[0067] The specific preparation process of the silicon-based / perovskite tandem solar cell is as follows: Step S1: polishing the N-type silicon wafer to a thickness of 500-1000 nm to obtain a crystalline silicon bottom cell absorption layer (c-Si) 24.

[0068] Step S2: Use PECVD to prepare front intrinsic amorphous silicon, n-type amorphous silicon, with a thickness of 25nm on the crystalline silicon bottom battery absorption layer (c-Si) 24 to obtain a second amorphous silicon passivation layer (a-Si:H(i) and a-Si:H(n) stacked in sequence) 25.

[0069] Step S3: Prepare back intrinsic amorphous silicon, p-type amorphous silicon, with a total thickness of 20 nm to obtain a first amorphous silicon passivation layer (a-Si:H(p) and a-Si:H(i) stacked in sequence) 23. Step S4: a front transparent conductive oxide ITO layer is prepared by sputtering with a thickness of 50 nm to obtain a tunneling layer (ITO) 26 .

[0070] Step S5: Prepare a back transparent conductive oxide ITO layer with a thickness of 110 nm by sputtering to obtain a second transparent conductive substrate (ITO) 22 .

[0071] Step S6: Prepare a hole transport layer NiOx by sputtering with a thickness of 15 nm to obtain a second hole transport layer (NiO x )27.

[0072] Step S7: Prepare a perovskite solution, wherein the structure of the perovskite precursor solution is: Cs 0.05 MA 0.15 FA 0.8 Pb(I 0.75 Br 0.25 ) 3 The specific formula of each component is: CsI (22.1 mg); MABr (28.5 mg); FAI (233.9 mg); PbI 2 (548.6mg); PbBr 2 (187.1 mg); dissolving the above perovskite raw material in 1 mL of a mixed solvent of 2-mercaptoethanol (2-ME) and dimethyl sulfoxide (DMSO), with the solvent volume ratio being 2ME:DMSO=9:1, to obtain a perovskite solution; the concentration of the perovskite solution is 1.7 M (i.e., 1.7 moles of perovskite material per liter of solution); Step S8: Add 2.5 μL of thioglycolic acid (TGA) to every 1 mL of the perovskite solution, and then heat and stir the mixed solution at 45° C. on a heated magnetic stirring table for 6 h to obtain a perovskite precursor solution.

[0073] Step S9: The perovskite precursor solution is placed in a temperature and humidity controlled environment (RH=25%, T=25°C), the substrate temperature is controlled at 75°C, and the coating speed is 30 mm / s, and coated on the second hole transport layer (NiO x ) 27 to prepare a perovskite layer, and then annealing at 110° C. for 20 min to prepare a second perovskite light absorbing layer (Perovskite) 28; the thickness of the second perovskite light absorbing layer (Perovskite) 28D is 1000 nm; Step S10: Using thermal evaporation method, a layer of lithium fluoride (LiF) with a thickness of about 12 nm, a layer of fullerene (C 60 ), and obtain the second electron transport layer (LiF and C stacked in sequence) 60 )29.

[0074] Step S11: Prepare the electron blocking layer SnO by atomic deposition method 2 , with a thickness of about 15 nm, to obtain the second hole blocking layer (SnO 2 )30. Step S12: sputtering the second hole blocking layer (SnO 2) 30 is provided with a 200 nm thick transparent conductive oxide ITO layer as a transparent electrode layer (ITO) 31; a silver grid electrode (Ag) 32 is then provided; and a silicon-based / perovskite laminated solar cell (device size is 105 mm×105 mm) is obtained.

[0075] Comparative Example 1 The single-junction perovskite solar cell of Comparative Example 1 was prepared by referring to the preparation method of Example 1, with the only difference being that the formula of the perovskite precursor solution of Comparative Example 1 was different, glycolic acid (GA) was not added to the perovskite precursor solution in Comparative Example 1, and the additive was a commercially available perovskite precursor solution additive.

[0076] Comparative Example 2 The silicon-based / perovskite tandem solar cell of Comparative Example 2 was prepared by referring to the preparation method of Example 17, with the only difference being that the formula of the perovskite precursor solution of Comparative Example 2 was different, and no thioglycolic acid (TGA) was added to the perovskite precursor solution in Comparative Example 3, and the additive was a commercially available perovskite precursor solution additive.

[0077] Table 1 Formula of perovskite precursor solution of Examples 2-8 Table 1

[0078] The following is a performance test of the perovskite solar cells provided in Examples 1-17 of the present application and Comparative Examples 1-2. The test results are shown in Table 2.

[0079] Table 2 Performance test results of perovskite solar cells of Examples 1-17 and Comparative Examples 1-2

[0080] Referring to the battery performance test results of Examples 1-17 and Comparative Examples 1-2, it can be seen that when a volatile solid acid is added as an additive to the perovskite precursor solution, the functional groups such as carboxyl, thiol, hydroxyl, and amino in the volatile solid acid can react with the FA in the perovskite material. + and PbI 2 A relatively strong interaction is generated between the two, which slows down the crystallization rate of the perovskite, passivates the defects of the perovskite crystals, and at the same time increases the grain size of the perovskite crystals, improving the quality of the prepared perovskite light-absorbing layer, thereby preparing a large-area perovskite light-absorbing layer with high coverage, flatness, density, and zero pinholes; and because the boiling point of the volatile solid acid is relatively low, after annealing treatment, there is no excess phase residue in the prepared perovskite light-absorbing layer except for the perovskite, which is beneficial to improving the film-forming quality and long-term stability of the perovskite light-absorbing layer, thereby further improving the photoelectric conversion rate of the perovskite solar cell.

[0081] Referring to the battery performance test results of Example 1 and Example 4, it can be seen that optimizing the structure of the perovskite material is helpful to increase the carboxyl, thiol, hydroxyl, amino and other functional groups in the volatile solid acid and the FA in the perovskite material. + and PbI 2 The interaction between them slows down the crystallization rate of perovskite and is beneficial to passivating the defects of perovskite crystals, thereby further improving the quality of the prepared perovskite light-absorbing layer and helping to improve the photoelectric conversion rate of perovskite solar cells.

[0082] Referring to the battery performance test results of Examples 1 and 6-8, it can be seen that organic solvents include 2-mercaptoethanol and dimethyl sulfoxide, and the dissolution effect of perovskite materials and volatile solid acids is better, thereby further improving the quality of the prepared perovskite light-absorbing layer, which is beneficial to improving the photoelectric conversion rate of perovskite solar cells.

[0083] Referring to the battery performance test results of Example 1 and Example 5, it can be seen that by optimizing the mixing ratio of 2-mercaptoethanol and dimethyl sulfoxide, the dissolution effect of the perovskite material and the volatile solid acid is better, thereby further improving the quality of the prepared perovskite light-absorbing layer, which is beneficial to improving the photoelectric conversion rate of the perovskite solar cell.

[0084] Referring to the battery performance test results of Examples 1 and 11-12, it can be seen that by optimizing the annealing process of the perovskite light absorbing layer, no excess phase remains except perovskite after annealing, which can improve the quality of the prepared perovskite light absorbing layer, thereby being able to prepare a large-area perovskite light absorbing layer with high coverage, flatness, density, and zero pinholes, which is beneficial to improving the photoelectric conversion rate of perovskite solar cells.

[0085] Referring to the battery performance test results of Examples 1, 9-10 and 13-16, it can be seen that optimizing the coating process of the perovskite light absorbing layer can improve the coating effect of the perovskite precursor solution, thereby improving the quality of the prepared perovskite light absorbing layer, thereby being able to prepare a large-area perovskite light absorbing layer with high coverage, flatness, density and zero pinholes, which is beneficial to improving the photoelectric conversion rate of perovskite solar cells.

[0086] The embodiment of the present application can provide a photovoltaic system, including the above-mentioned perovskite solar cell. The advantages of the above-mentioned perovskite solar cell are also possessed by the photovoltaic system, which will not be repeated here. The above-mentioned 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 can form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter to convert it into the alternating current required by the mains power grid and then connected to the mains network to realize solar power supply.

[0087] It should be noted that the terms "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", 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.

[0088] 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.

[0089] It should also be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this application refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0090] 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.

[0091] 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, additives, and organic solvents; Wherein, the additive comprises a volatile solid acid.

2. The perovskite precursor solution according to claim 1, characterized in that The volatile solid acid includes one or more of glycolic acid, thioglycolic acid and glycine.

3. The perovskite precursor solution according to claim 1, characterized in that The structure of the perovskite material is FA a MA b Cs c Pb(I m Br n )3.

4. The perovskite precursor solution according to claim 1, characterized in that The organic solvent includes 2-mercaptoethanol and dimethyl sulfoxide.

5. The perovskite precursor solution according to claim 4, characterized in that: The volume ratio of the 2-mercaptoethanol to the dimethyl sulfoxide is 8:1 to 15:

1.

6. A method for preparing a perovskite precursor solution, characterized in that: The perovskite precursor solution comprises: a perovskite material, an additive, and an organic solvent; the additive comprises a volatile solid acid; the volatile solid acid comprises: one or more of glycolic acid, thioglycolic acid, and glycine; Dissolving the perovskite material in the organic solvent and mixing them uniformly to prepare a perovskite solution; adding the additive to the perovskite solution and mixing them uniformly to obtain the perovskite precursor solution; Wherein, in the perovskite solution, the amount of the additive added satisfies at least one of the following characteristics: (1) When the additive is glycolic acid, the amount of the additive added to each milliliter of the perovskite solution is 1-5 mg; (2) When the additive is thioglycolic acid, the amount of the additive added to each milliliter of the perovskite solution is 0.5-2.5 μL; (3) When the additive is glycine, the amount of the additive added to each milliliter of the perovskite solution is 0.5-3.5 mg.

7. A perovskite solar cell, characterized in that: including a perovskite light absorbing layer; Wherein, the perovskite light absorbing layer is formed by the perovskite precursor solution according to any one of claims 1 to 5; Alternatively, the perovskite light-absorbing layer is formed by a perovskite precursor solution prepared by the preparation method as described in claim 6.

8. The perovskite solar cell according to claim 7, characterized in that: The perovskite solar cell is a single-junction perovskite solar cell or a silicon-based / perovskite stacked solar cell; the preparation method of the perovskite light-absorbing layer comprises: coating the perovskite precursor solution on a substrate by a slit extrusion coating method or a blade coating method, and then annealing at 100-120° C. for 20-30 minutes to form the perovskite light-absorbing layer.

9. The perovskite solar cell according to claim 8, characterized in that: The method for preparing the perovskite light absorbing layer meets at least one of the following characteristics: (1) When the perovskite precursor solution is coated on the substrate by a slit extrusion coating method or a blade coating method, the temperature and relative humidity of the environment meet the following conditions: RH = 20 ± 5%, T = 22 ± 5 °C; (2) When the perovskite precursor solution is coated on the substrate by a slit extrusion coating method or a doctor blade coating method, the temperature of the substrate is controlled at 73-77° C.; (3) The coating speed of the perovskite precursor solution is controlled at 28-32 mm / s.

10. A photovoltaic system, characterized in that: Comprising the perovskite solar cell as described in any one of claims 7-9.

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