Perovskite solar cell and preparation method thereof

Abstract

The invention relates to the technical field of photovoltaic power generation, discloses a perovskite solar cell and a preparation method thereof, and aims to improve the photoelectric conversion efficiency and prolong the service life of the perovskite solar cell. The perovskite solar cell comprises a substrate, a first carrier transport layer, a perovskite light absorption layer and a second carrier transport layer which are stacked in sequence, wherein the perovskite light absorption layer is prepared from a mixed solution containing a perovskite material precursor solution and an additive; wherein the additive is 2-(4-fluorophenyl) ethylamine hydrohalate, and the solvent is a solvent; or the solar cell also comprises a passivation layer arranged between the perovskite light absorption layer and the second carrier transmission layer; the perovskite light absorption layer is prepared from a mixed solution containing a perovskite material precursor solution and the additive, or / and the passivation layer is prepared from a passivation solution at least containing 2-(4-fluorophenyl) ethylamine haloid.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic power generation, and particularly to a perovskite solar cell and a preparation method thereof. BACKGROUND

[0002] With the advantages of low material cost, strong band gap adjustability, and high light absorption coefficient, perovskite solar cells have gradually become one of the most promising photovoltaic cells. Since the perovskite crystals in the perovskite light-absorbing layer are mainly composed of ionic bonds, the perovskite crystals are prone to breakage. In addition, the ion mobility in the perovskite light-absorbing layer is relatively high, and the perovskite light-absorbing layer is prone to dynamic changes in defects and interface degradation, resulting in insufficient stability of the perovskite light-absorbing layer, and high non-radiative recombination loss, thereby causing the perovskite solar cell to have problems of insufficient photoelectric conversion efficiency and insufficient service life. SUMMARY

[0003] The present application provides a perovskite solar cell and a preparation method thereof, to improve the photoelectric conversion efficiency and service life of the perovskite solar cell by improving the stability of the perovskite light-absorbing layer.

[0004] In a first aspect, the embodiments of the present application provide a perovskite solar cell, comprising a substrate, a first carrier transport layer, a perovskite light-absorbing layer, and a second carrier transport layer which are sequentially stacked, wherein the perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and an additive; and the additive is 2-(4-fluorophenyl)ethylamine hydrohalide. Alternatively, the perovskite solar cell further comprises a passivation layer arranged between the perovskite light-absorbing layer and the second carrier transport layer; the perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and the additive, and / or the passivation layer is prepared from a passivation solution containing at least 2-(4-fluorophenyl)ethylamine hydrohalide.

[0005] In some embodiments, the perovskite material has a chemical formula of ABX3, A is at least one monovalent cation, B is at least one divalent metal ion, and X is a halogen ion. In the case where the perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and an additive, the ratio of the molar amount of the additive to the molar amount of B ions in the perovskite material is 0.001-0.05:1.

[0006] In some embodiments, in the ABX3, A is at least one of FA + , MA + , and Cs + , B is Pb 2+ and / or Sn 2+ , and X at least contains Br - or I- ; and / or, The solvent of the perovskite material precursor solution is a mixed solvent of DMF and DMSO.

[0007] In some embodiments, in the case that the perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and an additive, The additive added in the perovskite material precursor solution includes 2-(4-fluorophenyl)ethylamine hydrobromide and / or 2-(4-fluorophenyl)ethylamine hydroiodide; and / or, The concentration of the additive in the mixed solution is less than or equal to 5 mg / mL; and / or, The thickness of the perovskite light-absorbing layer is 500-900 nm.

[0008] In some embodiments, in the case that the passivation layer is prepared from a passivation solution containing at least 2-(4-fluorophenyl)ethylamine hydrohalide, The 2-(4-fluorophenyl)ethylamine hydrohalide in the passivation solution includes 2-(4-fluorophenyl)ethylamine hydrobromide or 2-(4-fluorophenyl)ethylamine hydroiodide; and / or, The concentration of the 2-(4-fluorophenyl)ethylamine hydrohalide in the passivation solution is less than or equal to 5 mg / mL; and / or, The thickness of the passivation layer is 10-100 nm.

[0009] In some embodiments, the substrate is a conductive substrate or a bottom cell substrate; wherein, The conductive substrate includes a substrate and a transparent conductive layer disposed on the substrate; The bottom cell substrate includes a crystalline silicon solar cell, a CIGS thin-film solar cell, a cadmium telluride thin-film solar cell, a IIIV thin-film solar cell or a perovskite solar cell.

[0010] In a second aspect, the embodiments of the present application provide a preparation method of a perovskite solar cell, including sequentially preparing a first carrier transport layer, a perovskite light-absorbing layer and a second carrier transport layer which are stacked on a substrate, and the preparation of the perovskite light-absorbing layer includes: Coating a mixed solution containing a perovskite material precursor solution and an additive on the first carrier transport layer, and annealing to form the perovskite light-absorbing layer; The additive is 2-(4-fluorophenyl)ethylamine hydrohalide.

[0011] In some embodiments, the concentration of the additive in the mixed solution is less than or equal to 5 mg / mL, preferably 0.5-3 mg / mL; and / or, In the process of preparing the perovskite light-absorbing layer, the annealing temperature is 90-120℃; and / or, The thickness of the prepared perovskite light-absorbing layer is 500-900 nm.

[0012] In a third aspect, the embodiments of the present application provide a method for preparing a perovskite solar cell, comprising sequentially preparing a first carrier transport layer, a perovskite light-absorbing layer, a passivation layer and a second carrier transport layer on a substrate, wherein the preparation of the perovskite light-absorbing layer comprises: coating a mixed solution containing a perovskite material precursor solution and an additive on the first carrier transport layer, and performing annealing treatment to form the perovskite light-absorbing layer on the first carrier transport layer; wherein the additive is 2-(4-fluorophenyl)ethylamine hydrohalide. and / or, The preparation of the passivation layer comprises: coating a passivation solution containing at least 2-(4-fluorophenyl)ethylamine hydrohalide on the perovskite light-absorbing layer, and performing annealing treatment to form the passivation layer on the perovskite light-absorbing layer.

[0013] In some embodiments, for the case that the perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and an additive, the concentration of the additive in the mixed solution is less than or equal to 5 mg / mL, preferably 0.5-3 mg / mL; For the case that the passivation layer is prepared from a passivation solution containing at least 2-(4-fluorophenyl)ethylamine hydrohalide, the concentration of 2-(4-fluorophenyl)ethylamine hydrohalide in the passivation solution is less than or equal to 5 mg / mL, preferably 0.1-3 mg / mL.

[0014] In some embodiments, in the process of preparing the perovskite light-absorbing layer, the annealing temperature is 90-120℃; in the process of preparing the passivation layer, the annealing temperature is 50-90℃; and / or, The thickness of the prepared perovskite light-absorbing layer is 500-900 nm; the thickness of the prepared passivation layer is 10-100 nm.

[0015] Compared with the prior art, the perovskite solar cell provided by the embodiment of the present application has at least the following beneficial effects: in the perovskite solar cell, when the perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and an additive, the perovskite light-absorbing layer can inhibit the migration of ions in the perovskite light-absorbing layer to the second carrier transport layer above it through the steric hindrance effect of the 2-(4-fluorophenyl)ethylamine cation with a larger ion radius in the 2-(4-fluorophenyl)ethylamine hydrohalide, thereby effectively reducing the non-radiative recombination loss of the perovskite light-absorbing layer and improving the photoelectric conversion efficiency and service life of the perovskite solar cell. Moreover, the amine group in the 2-(4-fluorophenyl)ethylamine cation can form a hydrogen bond with the lead ion on the surface of the perovskite light-absorbing layer, and the fluorophenyl group is combined with the surface of the perovskite light-absorbing layer through van der Waals force, thereby enhancing the hydrophobicity of the perovskite light-absorbing layer, and the electronegativity of the fluorine atom can further improve the hydrophobicity of the upper surface of the perovskite light-absorbing layer, further improving the stability of the perovskite light-absorbing layer.

[0016] When the perovskite solar cell provided by the embodiment of the present application includes a passivation layer arranged between the perovskite light-absorbing layer and the second carrier transport layer, the passivation layer is prepared from a passivation solution containing 2-(4-fluorophenyl)ethylamine halide, so the amine group, fluorophenyl group and halide ion in the 2-(4-fluorophenyl)ethylamine halide in the passivation layer self-assemble on the surface of the perovskite light-absorbing layer under intermolecular forces to form the passivation layer, thereby achieving the effect of enhancing the hydrophobicity of the surface of the perovskite light-absorbing layer and adjusting the energy level matching between the perovskite light-absorbing layer and the second carrier transport layer, thereby improving the charge extraction efficiency. Meanwhile, the halide ion can fill the halide ion hole sites on the surface of the perovskite light-absorbing layer to achieve defect passivation. In this way, the perovskite light-absorbing layer and / or the passivation layer can improve the carrier transport efficiency in the perovskite light-absorbing layer while reducing the defect density and non-radiative loss, and the photoelectric conversion efficiency and service life of the perovskite solar cell are further enhanced. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 XRD comparison chart of the examples and comparative examples provided by the embodiment of the present application; Figure 2 Partial enlarged view of the XRD chart of the perovskite light-absorbing layer in Example 1-1 provided by the embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and are not used to limit the present application.

[0019] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the document does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0020] As illustrated herein, unless the context clearly indicates otherwise, the words “a,” “an,” “an,” and / or “the” do not specifically refer to the singular and may also include the plural. Generally speaking, the terms “comprising” and “including” only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0021] In this embodiment of the invention, prefixes such as "first" and "second" are used merely to distinguish different descriptive objects and do not limit the position, order, priority, quantity, or content of the described objects. The use of ordinal numbers and other prefixes to distinguish descriptive objects in this application does not constitute a limitation on the described objects. For statements regarding the described objects, please refer to the claims or the context of the embodiments. The use of such prefixes should not constitute unnecessary limitations. Furthermore, in the description of this embodiment, unless otherwise stated, "multiple" means two or more.

[0022] To address the issues of insufficient photoelectric conversion efficiency and lifespan in perovskite solar cells caused by instability of the perovskite light-absorbing layer and non-radiative recombination losses, this application first provides a perovskite solar cell. This perovskite solar cell comprises a substrate, a first carrier transport layer, a perovskite light-absorbing layer, and a second carrier transport layer, stacked sequentially.

[0023] The perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and an additive. The additive is 2-(4-fluorophenyl)ethylamine hydrohalate.

[0024] Alternatively, the perovskite solar cell provided in this application embodiment further includes a passivation layer disposed between the perovskite light-absorbing layer and the second carrier transport layer. The perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and additives, and / or the passivation layer is prepared from a passivation solution containing at least 2-(4-fluorophenyl)ethylamine hydrohalate.

[0025] The following description focuses on the first embodiment described above: the perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and additives.

[0026] Understandably, in this embodiment, the perovskite solar cell may not contain a passivation layer.

[0027] The additives in the above mixed solution contain -NH 3+ Can be reacted with solvents (e.g., DMF or DMSO) or halide ions (e.g., I₂). - Hydrogen bonds are formed, effectively slowing down the crystallization rate and promoting the formation of large grains. The hydrophobicity of the benzene ring and the electronegativity (−F) of the fluorine atom in fluorophenyl (−C6H4F) can regulate the colloidal behavior of the perovskite precursor solution, suppressing the nucleation density, thereby reducing grain boundary defects in the perovskite light-absorbing layer and improving the film uniformity of the perovskite light-absorbing layer. This can effectively reduce the non-radiative recombination loss of the perovskite light-absorbing layer in perovskite solar cells, and further enhance the long-term stability of perovskite solar cells and the photovoltaic devices they are located in.

[0028] Further, in one embodiment, the perovskite material in the perovskite light-absorbing layer has the chemical formula ABX3. It has a characteristic crystal phase with [BX6] octahedral as the basic structural unit. Wherein, A is at least one monovalent cation, B is at least one divalent metal ion, and X is a halide ion. The molar ratio of this additive to the molar ratio of B ions in the perovskite material is 0.001 to 0.05:1.

[0029] In the chemical formula of the perovskite material described above, the A-site cation is also called the interstitial cation. This interstitial cation fills the octahedral structure. The B-site cation is also called the octahedral central metal ion. This octahedral central metal ion is located at the center of the octahedron. The X-site anion can also be called the octahedral vertex anion. This octahedral vertex anion is located at the vertex of the octahedron.

[0030] In one embodiment, A is a formamidinium cation FA. + methylamine cationic MA + Cesium ions (Cs) + At least one of them; B is Pb 2+ and / or Sn 2+ X includes at least Br - Or I - Wherein, when the perovskite material is a wide-bandgap perovskite material, X includes at least Br. - When the perovskite material is a narrow bandgap material, X includes at least I. - For example, the chemical formula of this perovskite material is: Cs α MA β FA θ B(X' x Br 1-x )3, where X' is X excluding Br - For halogen ions other than α+β+θ=1, 0≤x≤0.85.

[0031] In the above embodiments, the amine group (−NH) contained in the 2-(4-fluorophenyl)ethylamine cation in the additive 3+ ) and B (e.g., Pb) in perovskite material ABX3 2+ fluorophenyl (−C6H4F) is linked by hydrogen bonds to divalent metal cations B (e.g., Pb) in perovskite materials via van der Waals forces. 2+ These components combine to form a two-dimensional phase. This two-dimensional phase can appear as a discontinuous two-dimensional layer above the perovskite light-absorbing layer. This two-dimensional layer can effectively alleviate the nonradiative recombination caused by the high defect density in the perovskite light-absorbing layer by covering the defects on the perovskite light-absorbing layer.

[0032] Meanwhile, the aforementioned additives can adjust the energy level matching between the perovskite light-absorbing layer and the second carrier transport layer, optimize the transport efficiency of the second carrier transport layer, and further alleviate the nonradiative recombination loss of carriers in the perovskite light-absorbing layer.

[0033] Furthermore, in the aforementioned first and second carrier transport layers, one is an electron transport layer and the other is a hole transport layer. In one embodiment, the perovskite solar cell can be a positive (normal) solar cell. Alternatively, in one embodiment, the perovskite solar cell can also be an inverted (reverse) solar cell. For example, if the first carrier transport layer is an electron transport layer, then the second carrier transport layer is a hole transport layer. In this case, the perovskite solar cell is a positive solar cell.

[0034] Continuing with the example: if the first carrier transport layer is a hole transport layer, then the second carrier transport layer is an electron transport layer. Therefore, this perovskite solar cell is an inverted solar cell.

[0035] Furthermore, the solvent of the perovskite material precursor solution is a mixed solvent of DMF (N,N-Dimethylformamide) and DMSO (Dimethyl sulfoxide).

[0036] In one embodiment, the volume ratio between DMF and DMSO is (3~7):1. Exemplarily, the volume ratio between DMF and DMSO can be 3:1, 4:1, 5:1, 6:1, 7:1, etc.

[0037] Furthermore, the 2-(4-fluorophenyl)ethylamine hydrohalate in the perovskite light-absorbing layer may include at least one of 2-(4-fluorophenyl)ethylamine hydrofluoric acid, 2-(4-fluorophenyl)ethylamine hydrohalochlorate, 2-(4-fluorophenyl)ethylamine hydrobromide, and 2-(4-fluorophenyl)ethylamine hydroiodate.

[0038] Preferably, 2-(4-fluorophenyl)ethylamine hydrohalate includes 2-(4-fluorophenyl)ethylamine hydrobromide and / or 2-(4-fluorophenyl)ethylamine hydroiodide.

[0039] Optionally, the perovskite material described above may include a wide bandgap perovskite material. The bandgap width of the wide bandgap perovskite material may be greater than or equal to 1.65 eV. In this embodiment, the additive includes at least 2-(4-fluorophenyl)ethylamine hydrobromide to fill the bromine vacancies caused by volatilization through bromide ions in the 2-(4-fluorophenyl)ethylamine hydrobromide, reducing defects and mitigating non-radiative recombination losses on the surface of the perovskite light-absorbing layer.

[0040] Optionally, the perovskite material described above may include a narrow bandgap perovskite material. The bandgap width of this narrow bandgap perovskite material may be less than or equal to 1.55 eV. It contains a high content of iodine vacancies; therefore, in this embodiment, the additive at least includes 2-(4-fluorophenyl)ethylamine hydroiodate, so that the iodine ions in 2-(4-fluorophenyl)ethylamine hydroiodate fill the iodine vacancies caused by volatilization, effectively mitigating the non-radiative recombination loss caused by the high content of surface defects in the perovskite light-absorbing layer.

[0041] In one embodiment, the concentration of the above-mentioned additive in the mixed solution containing the perovskite material precursor solution and the additive is less than or equal to 5 mg / mL.

[0042] Furthermore, the following description pertains to an embodiment in which a passivation layer is also disposed between the perovskite light-absorbing layer and the second carrier transport layer in a perovskite solar cell. In this embodiment, the perovskite light-absorbing layer is prepared from a mixed solution comprising a perovskite material precursor solution and additives. And / or, the passivation layer is prepared from a passivation solution comprising at least 2-(4-fluorophenyl)ethylamine hydrohalate.

[0043] Optionally, the aforementioned passivation layer is prepared from a passivation solution containing at least 2-(4-fluorophenyl)ethylamine hydrohalate. In this case, the perovskite light-absorbing layer can be prepared from a perovskite material precursor solution without the added additive.

[0044] Optionally, the perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and additives. In this case, the passivation layer can be prepared from a passivation solution containing a passivation material, but the passivation solution does not contain the aforementioned 2-(4-fluorophenyl)ethylamine hydrohalate.

[0045] Optionally, the perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and additives. Furthermore, the passivation layer is prepared from a passivation solution containing at least 2-(4-fluorophenyl)ethylamine hydrohalate.

[0046] Understandably, in this embodiment, the case where the perovskite light-absorbing layer is prepared by mixing a solution containing a perovskite material precursor and additives is the same as the aforementioned embodiment where the perovskite light-absorbing layer is prepared by mixing a solution containing a perovskite material precursor and additives. For any repetitions, please refer to the relevant content above, and it will not be repeated here.

[0047] When the passivation layer contains 2-(4-fluorophenyl)ethylamine hydrohalate, the passivation layer can optimize the energy level matching between the perovskite light-absorbing layer and the second carrier transport layer through 2-(4-fluorophenyl)ethylamine hydrohalate, thereby improving the transport efficiency of carriers through the second carrier transport layer.

[0048] The passivation solution may further include a passivation material. This passivation material may include at least one of organic ammonium salts, inorganic salts, metal oxides, polymers, and functional molecules. Specifically, the organic ammonium salt may be selected from at least one of propylenediamine iodine, butylamine chloride, and phenylethylamine; the inorganic salt may be selected from at least one of magnesium fluoride, lithium fluoride, and sodium fluoride; the metal oxide may be selected from alumina and / or silicon dioxide; the polymer may be selected from polymethyl methacrylate; and the functional molecule may be selected from methyl [6,6]-phenyl C61 butyrate.

[0049] Furthermore, the 2-(4-fluorophenyl)ethylamine hydrohalate in the passivation solution may include at least one of 2-(4-fluorophenyl)ethylamine hydrofluoric acid, 2-(4-fluorophenyl)ethylamine hydrohalochlorate, 2-(4-fluorophenyl)ethylamine hydrobromide, and 2-(4-fluorophenyl)ethylamine hydroiodate.

[0050] Preferably, the 2-(4-fluorophenyl)ethylamine hydrohalate includes 2-(4-fluorophenyl)ethylamine hydrobromide and / or 2-(4-fluorophenyl)ethylamine hydroiodide. The selection of the 2-(4-fluorophenyl)ethylamine hydrobromide and 2-(4-fluorophenyl)ethylamine hydroiodide depends on whether the perovskite material is a wide-bandgap perovskite material or a narrow-bandgap perovskite material. For details, please refer to the section on the selection of 2-(4-fluorophenyl)ethylamine hydrohalate in the aforementioned mixed solution containing perovskite material precursor solution and additives, which will not be repeated here.

[0051] Furthermore, to avoid high levels of 2-(4-fluorophenyl)ethylamine hydrohalate in the passivation solution hindering carrier transport, in one embodiment, the concentration of 2-(4-fluorophenyl)ethylamine hydrobromide in the passivation solution is less than or equal to 5 mg / mL. Exemplarily, the concentration of 2-(4-fluorophenyl)ethylamine hydrohalate in the passivation solution can be 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL, or 5 mg / mL, etc.

[0052] Understandably, in the embodiments of this application, a two-dimensional layer is formed on the surface of the perovskite light-absorbing layer by using a mixed solution containing a perovskite material precursor solution and additives, and / or 2-(4-fluorophenyl)ethylamine hydrohalate in the passivation solution. This two-dimensional layer can be composed of discontinuous two-dimensional phases or a continuous two-dimensional layer. Therefore, for perovskite solar cells without a passivation layer, X-ray diffraction (XRD) tests are performed on the perovskite light-absorbing layer; for perovskite solar cells containing a passivation layer, especially when the passivation layer is prepared from a passivation solution containing 2-(4-fluorophenyl)ethylamine hydrohalate, XRD tests are performed on the passivation layer. The resulting XRD patterns all include: a first diffraction peak corresponding to the two-dimensional layer, and a second diffraction peak corresponding to the perovskite light-absorbing layer.

[0053] The first diffraction peak has a diffraction angle of less than 10°, and the second diffraction peak has a diffraction angle of greater than 12.5°. In one embodiment, the first diffraction peak includes diffraction peaks with diffraction angles between 7.8° and 8.2°.

[0054] In one embodiment, the second diffraction peak includes at least one diffraction peak with a diffraction angle located at 12.8°~13.2°, 13.8°~14.2°, and 23.8°~24.2°.

[0055] Understandably, in the perovskite solar cell provided in the embodiments of this application, the intensity of the first diffraction peak increases with the increase of the content of the two-dimensional layer.

[0056] In one embodiment, the thickness of the perovskite light-absorbing layer is 500-900 nm. The thickness of the passivation layer is 10-100 nm.

[0057] Furthermore, the hole transport layer described above may include, but is not limited to, hole transport materials. The thickness of the hole transport layer may be 5~100 nm. The hole transport layer may include transition metal oxides and / or SAM (self-assembled monolayer).

[0058] The transition metal oxide may include at least one of nickel oxide, molybdenum oxide, vanadium oxide, and chromium oxide. The SAM layer may include at least one of [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid, and [6-(3,6-dimethoxy-9H-carbazole-9-yl)hexyl]phosphonic acid.

[0059] The electron transport layer may include, but is not limited to, at least one of C60, titanium dioxide, and tin dioxide. The thickness of the electron transport layer is 5~100 nm.

[0060] Furthermore, the perovskite solar cell described above may also include a metal electrode, such as a silver electrode. This metal electrode may be located above the second carrier transport layer.

[0061] Furthermore, the aforementioned substrate can be a conductive substrate or a bottom battery substrate.

[0062] When a perovskite solar cell is a single-junction cell, the conductive substrate may include a substrate and a transparent conductive layer disposed on the substrate.

[0063] In one embodiment, the substrate may be glass. The transparent conductive layer may include at least one of an indium tin oxide layer, an indium tungsten oxide layer, an aluminum-doped zinc oxide layer, or a boron-doped zinc oxide layer.

[0064] Alternatively, when the perovskite solar cell is a tandem cell, the aforementioned substrate serves as the base cell substrate. This base cell substrate may include crystalline silicon solar cells, CIGS thin-film solar cells, cadmium telluride thin-film solar cells, IIIV thin-film solar cells, or perovskite solar cells.

[0065] Based on the same inventive concept, this application provides a method for fabricating a perovskite solar cell, which may include the following steps: A first carrier transport layer, a perovskite light-absorbing layer, and a second carrier transport layer are sequentially stacked on a substrate. The perovskite light-absorbing layer is obtained by coating a mixed solution containing a perovskite material precursor solution and an additive onto the first carrier transport layer, followed by annealing to form the perovskite light-absorbing layer. The additive is 2-(4-fluorophenyl)ethylamine hydrohalide. Exemplarily, firstly, the additive can be uniformly mixed with the perovskite material precursor solution; then, the aforementioned mixed solution can be coated onto the first carrier transport layer and annealed to form the perovskite light-absorbing layer on the first carrier transport layer.

[0066] Specifically, the coating can be applied by slot coating, spin coating, or spray coating; spin coating is preferred.

[0067] The aforementioned 2-(4-fluorophenyl)ethylamine hydrohalate may be selected from at least one of the following: 2-(4-fluorophenyl)ethylamine hydrofluoric acid, 2-(4-fluorophenyl)ethylamine hydrohalochlorate, 2-(4-fluorophenyl)ethylamine hydrobromide, and 2-(4-fluorophenyl)ethylamine hydroiodate. The annealing step described above can be performed at ambient pressure (atmospheric pressure) at a temperature of 90–120°C.

[0068] In one embodiment, the concentration of the additive in the above mixed solution is less than or equal to 5 mg / mL, preferably 0.5 to 3 mg / mL.

[0069] In one embodiment, the concentration of B ions in the perovskite precursor solution is 0.8 ~ 1.8 mmol / mL.

[0070] In one embodiment, the molar ratio of 2-(4-fluorophenyl)ethylamine hydrohalate to the molar ratio of B ions in the perovskite precursor solution is 0.001 to 0.05. Exemplarily, the molar ratio of 2-(4-fluorophenyl)ethylamine hydrohalate to the molar ratio of B ions in the perovskite precursor solution can be 0.001, 0.005, 0.01, 0.015, 0.12, 0.025, 0.03, 0.035, 0.04, 0.045, or 0.05, etc.

[0071] Based on the same inventive concept, this application also provides a method for fabricating a perovskite solar cell, which includes sequentially fabricating a first carrier transport layer, a perovskite light-absorbing layer, a passivation layer, and a second carrier transport layer on a substrate.

[0072] The preparation of the perovskite light-absorbing layer includes coating a mixed solution containing a perovskite material precursor solution and an additive onto a first carrier transport layer, followed by annealing to form a perovskite light-absorbing layer on the first carrier transport layer. The additive is 2-(4-fluorophenyl)ethylamine hydrohalide.

[0073] And / or, the preparation of the passivation layer includes coating a passivation solution containing at least 2-(4-fluorophenyl)ethylamine hydrohalate onto a perovskite light-absorbing layer and annealing the solution to form the passivation layer on the perovskite light-absorbing layer.

[0074] The passivation solution may also include PEAI (Phenethylammonium iodide) and / or BAI (Butylammonium iodide), which can also anneal with the second wet film to form a passivation layer. This layer works in synergy with the two-dimensional layer formed by 2-(4-fluorophenyl)ethylamine hydrohalide in the passivation solution to solve the problems of nonradiative recombination loss and insufficient stability caused by the high defect density of the perovskite light-absorbing layer in perovskite solar cells.

[0075] Furthermore, the solvent for the passivation solution can be selected from at least one of isopropanol, ethanol, acetonitrile, and tetrahydrofuran.

[0076] The concentration of 2-(4-fluorophenyl)ethylamine hydrohalate in the passivation solution is less than or equal to 5 mg / mL, preferably 0.1~3 mg / mL.

[0077] Thus, when the passivation solution contains 2-(4-fluorophenyl)ethylamine hydrohalate, the 2-(4-fluorophenyl)ethylamine hydrohalate in the passivation solution can continue to self-assemble on the surface of the perovskite light-absorbing layer: through the amino groups (−NH) in the 2-(4-fluorophenyl)ethylamine hydrohalate...3+ Pb on the perovskite surface 2+ Ions form hydrogen bonds. Also, halide anions (X−) interact with halide ion vacancies or Pb sites on the surface of the perovskite absorbing layer. 2+ By combining these elements, the two-dimensional layer is further stabilized, while the van der Waals forces and steric hindrance effects of fluorophenyl (−C6H4F) promote the orderly and dense arrangement of molecules in the two-dimensional layer on the surface of the perovskite light-absorbing layer.

[0078] Understandably, in the above-mentioned perovskite material precursor solution, the component ratio of the perovskite material precursor is set according to the chemical formula of the perovskite material. For example, the perovskite material precursor includes ABr and / or BBr2, and AX' and / or BX'2. Wherein, A is a monovalent cation, B is a divalent metal cation, and X' is a halide ion other than bromide ions. A, B, and X' are all consistent with A, B, and X' in the perovskite material. For example, ABr can be selected from methylammonium bromide (MABr) and / or formamidine bromide (FABr), BBr2 can be lead bromide (PbBr2), AX' is selected from cesium iodide (CsI) and / or formamidine hydroiodate (FAI), and BX'2 is selected from lead iodide (PbI2) and / or PbCl2.

[0079] Furthermore, one of the first carrier transport layer and the second carrier transport layer is an electron transport layer, and the other is a hole transport layer. The hole transport layer is prepared by coating, physical vapor deposition, chemical vapor deposition, or atomic layer deposition. The electron transport layer is prepared by coating, physical vapor deposition, chemical vapor deposition, or atomic layer deposition; the electrode layer is prepared by physical vapor deposition. The coating can be selected from slot coating, spin coating, or spray coating. The physical vapor deposition can be selected from evaporation.

[0080] Furthermore, when a perovskite light-absorbing layer is prepared by means of a mixed solution containing a perovskite material precursor solution and an additive, and the passivation solution contains 2-(4-fluorophenyl)ethylamine hydrohalate, the type of halide ions contained in the additive may be the same as or different from the type of halide ions contained in the 2-(4-fluorophenyl)ethylamine hydrohalate in the passivation solution, preferably the same.

[0081] The halide ions of the 2-(4-fluorophenyl)ethylamine hydrohalate in the aforementioned additives and passivation solutions can correspond to defects in the perovskite absorbing layer. In one embodiment, when the perovskite absorbing layer is a wide bandgap perovskite layer, it is mainly prepared by using a high content of bromide ions in the perovskite material precursor. Therefore, the wide bandgap perovskite layer contains a large number of bromine vacancies caused by bromide ion volatilization. Therefore, when the bandgap of the perovskite absorbing layer is greater than or equal to 1.65 eV, the 2-(4-fluorophenyl)ethylamine hydrohalate includes at least 2-(4-fluorophenyl)ethylamine hydrobromide to fill the aforementioned volatilization-induced bromine vacancies with bromide ions from the 2-(4-fluorophenyl)ethylamine hydrobromide, reducing non-radiative recombination losses caused by defects.

[0082] Similarly, when the band gap of the perovskite absorbing layer is less than or equal to 1.55 eV, it is a narrow band gap perovskite layer with a high iodine vacancy content. Therefore, 2-(4-fluorophenyl)ethylamine hydrohalide includes at least 2-(4-fluorophenyl)ethylamine hydroiodate to fill the iodine vacancies caused by the above-mentioned volatilization with iodine ions in 2-(4-fluorophenyl)ethylamine hydroiodate, thereby reducing non-radiative recombination losses caused by defects.

[0083] Furthermore, the concentration of B ions in the perovskite precursor solution is 0.8 ~ 1.8 mmol / mL.

[0084] Furthermore, the ratio of the molar amount of the additive in the above mixed solution to the molar amount of B ions in the perovskite precursor solution is 0.001~0.05:1.

[0085] The solvent for the perovskite precursor solution is an organic solvent. This organic solvent may include DMF and / or DMSO. When the organic solvent consists of DMF and DMSO, the volume ratio of DMF to DMSO is (3~7):1.

[0086] Furthermore, during the preparation of the perovskite light-absorbing layer, the annealing temperature is 90~120℃. Specifically, the first wet film formed by coating the above mixed solution is annealed at a temperature of 90~120℃ to obtain the aforementioned perovskite light-absorbing layer. Exemplarily, the annealing temperature can be selected from 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, or 120℃, etc. In detail, during the annealing process of the first wet film, the perovskite precursor in the perovskite precursor solution crystallizes. Simultaneously, the additive, namely 2-(4-fluorophenyl)ethylamine hydrohalide, self-assembles on the surface of the perovskite grains on the side away from the substrate, where the amino groups (−NH...)... 3+ ) and divalent metal cations (e.g., Pb) in perovskite materials 2+ They form hydrogen bonds.

[0087] Furthermore, when the perovskite absorbing layer is a wide-bandgap perovskite layer, and an additive containing 2-(4-fluorophenyl)ethylamine hydrobromide is added to the perovskite precursor solution, since bromide ions easily volatilize during the first wet film annealing, in one embodiment, to reduce defects within the bulk phase of the perovskite absorbing layer, the annealing temperature (i.e., the first wet film annealing temperature) during the preparation of the perovskite absorbing layer can be 90~120℃, preferably 90~110℃. Exemplarily, the first wet film annealing temperature in this embodiment can be selected from 90℃, 95℃, 100℃, 105℃, 110℃, etc.

[0088] In the above-mentioned method for preparing perovskite solar cells, the crystallization reaction of the perovskite precursor is adjusted by adding 2-(4-fluorophenyl)ethylamine hydrohalate to the perovskite precursor solution, which effectively reduces the defect density in the perovskite light-absorbing layer and improves the film uniformity of the perovskite light-absorbing layer, thereby alleviating the non-radiative recombination loss of the perovskite light-absorbing layer.

[0089] The regulation of the crystallization reaction of perovskite precursors by the aforementioned 2-(4-fluorophenyl)ethylamine hydrohalate is explained as follows: During the formation of the first wet film and coating process, 2-(4-fluorophenyl)ethylamine hydrohalate participates in the crystallization of the perovskite precursor. The amine groups can form hydrogen bonds with the solvent and iodine ions in the aforementioned mixed solution, slowing down the perovskite crystallization rate and promoting an increase in perovskite grain size, thereby reducing grain boundary defects in the perovskite light-absorbing layer. Simultaneously, the benzene ring in 2-(4-fluorophenyl)ethylamine hydrohalate has hydrophobic properties, and the fluorine atom has electronegativity. These two components constitute the amphiphilic molecular structure of 2-(4-fluorophenyl)ethylamine hydrohalate, which can synergistically regulate the colloidal behavior in the aforementioned mixed solution, inducing the formation of dynamic nano-aggregates in the perovskite precursor, generating a nano-pre-assembly effect. While controlling ion diffusion, it effectively suppresses the nucleation density of perovskite grains, effectively alleviating the problem of high defect density in the perovskite light-absorbing layer and reducing non-radiative recombination losses in the perovskite light-absorbing layer.

[0090] In one embodiment, the annealing temperature during the preparation of the passivation layer is 50-90°C. Specifically, a passivation solution can be first applied to form a second wet film on the perovskite light-absorbing layer, and then the second wet film is annealed at a temperature of 50-90°C to allow 2-(4-fluorophenyl)ethylamine hydrohalate to self-assemble on the perovskite light-absorbing layer, forming a two-dimensional layer; thus, the passivation layer is obtained. More specifically, the temperature conditions for the second wet film can be selected from 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, or 90°C, etc. Because the annealing temperature of the second wet film is relatively low, the halide ions in the 2-(4-fluorophenyl)ethylamine hydrohalate can remain essentially non-volatile, thereby filling the halide ion vacancies in the perovskite light-absorbing layer or combining with divalent metal cations (e.g., Pb).2+ This allows the perovskite solar cell to form a two-dimensional layer through self-assembly, thereby improving the long-term stability of the perovskite solar cell and reducing defects in the bulk phase of the perovskite light-absorbing layer, further alleviating the problem of non-radiative recombination loss in the perovskite light-absorbing layer.

[0091] It should be noted that, due to the low annealing temperature for forming the passivation layer, when the 2-(4-fluorophenyl)ethylamine hydrohalate includes 2-(4-fluorophenyl)ethylamine hydrobromide, the bromide ions therein can be essentially non-volatile. However, the wide bandgap perovskite layer generates a large number of bromide ion vacancies due to the volatilization of bromide ions during the annealing step. Therefore, the aforementioned method for preparing perovskite solar cells is particularly suitable for embodiments where the bandgap of the perovskite light-absorbing layer is wide bandgap calcium. In this case, the high defect density caused by the high bromide ion content can be effectively improved by using bromide ions in the 2-(4-fluorophenyl)ethylamine hydrobromide in the passivation solution.

[0092] Furthermore, to avoid excessive 2-(4-fluorophenyl)ethylamine hydrobromide content hindering carrier transport, in one embodiment, the concentration of 2-(4-fluorophenyl)ethylamine hydrobromide in the passivation solution is less than or equal to 5 mg / mL. Exemplarily, the concentration of 2-(4-fluorophenyl)ethylamine hydrobromide in the passivation solution can be 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL, or 5 mg / mL, etc. In this embodiment, the perovskite material precursor solution may be free of 2-(4-fluorophenyl)ethylamine hydrobromide.

[0093] Alternatively, the perovskite precursor solution may contain 2-(4-fluorophenyl)ethylamine hydrobromide. When the perovskite precursor solution contains 2-(4-fluorophenyl)ethylamine hydrobromide, the molar ratio of the 2-(4-fluorophenyl)ethylamine hydrohalide in the perovskite precursor solution to the molar ratio of B ions in the perovskite material is 0.001 to 0.05. For example, this molar ratio may be 0.001, 0.005, 0.01, 0.015, 0.12, 0.025, 0.03, 0.035, 0.04, 0.045, or 0.05, etc.

[0094] In one embodiment, when the perovskite material precursor solution includes 2-(4-fluorophenyl)ethylamine hydrobromide, the method for preparing the aforementioned perovskite light-absorbing layer may include: First, the first wet film formed from the perovskite precursor solution coated on the surface of the first carrier transport layer is annealed at a temperature of 90~100℃ to crystallize the perovskite precursor in the wet film. Due to its large volume, the 2-(4-fluorophenyl)ethylamine cation in the 2-(4-fluorophenyl)ethylamine hydrobromide moves upwards and combines with the B-site cation of the perovskite ABX3 on the surface of the perovskite material, forming a two-dimensional phase. Understandably, because the molar ratio of 2-(4-fluorophenyl)ethylamine hydrohalide to the molar ratio of the perovskite precursor solution is 0.001~0.05, and the content of 2-(4-fluorophenyl)ethylamine hydrohalide is low, this two-dimensional phase is a discontinuous layer on the surface of the perovskite light-absorbing layer.

[0095] The passivation solution is then coated onto the perovskite light-absorbing layer, forming a second wet film. After annealing the second wet film at 50-90°C, the 2-(4-fluorophenyl)ethylamine hydrohalate contained in the second wet film continues to self-assemble on the aforementioned perovskite light-absorbing layer. Halogen ions continue to fill the halide ion vacancies on the surface of the perovskite light-absorbing layer and bond with B-site cations through hydrogen bonds, forming a stable and dense two-dimensional layer.

[0096] The following examples and comparative examples provide a more detailed description of the aforementioned perovskite solar cells and their fabrication methods.

[0097] Example 1-1 S1, with a size of 1×1cm 2 The ITO glass substrate was ultrasonically cleaned sequentially by immersion in ethanol, detergent, ultrapure water, isopropanol, and ethanol. The volume of solvent used for each ultrasonic cleaning was 500 mL, and the ultrasonic cleaning time was 15 minutes. The cleaned ITO glass substrate was then dried with nitrogen gas.

[0098] S2, 2−(3,6−dimethyl−9H−carbazole−9−yl)ethylphosphonic acid Me-2PACz was dissolved in anhydrous ethanol to obtain a 0.5 mg / mL Me-2PACz solution. The Me-2PACz solution was then spin-coated onto the surface of an ITO glass substrate. The spin-coating process parameters were: spin-coating at 3000 rpm for 30 s, followed by annealing at 100°C for 10 minutes to form a hole transport layer.

[0099] S3, the perovskite material precursors methylamine bromide (MABr), lead iodide (PbI2), lead bromide (PbBr2), cesium iodide (CsI), and formamidinium hydroiodate (FAI) are prepared according to the chemical formula Cs of the perovskite material. 0.05 MA 0.15 FA 0.8 Pb(I0.7 Br 0.3 3. Determine the mixing ratio and mix the mixture. Dissolve the mixture in an organic solvent to form a perovskite material precursor solution. The concentration of lead ions in the perovskite material precursor solution is 1.5 mol / L. The organic solvent for the perovskite material precursor solution consists of DMF and DMSO in a volume ratio of 4:1.

[0100] Furthermore, 2-(4-fluorophenyl)ethylamine hydrobromide was added as an additive to the above-mentioned perovskite precursor solution. The concentration of 2-(4-fluorophenyl)ethylamine hydrobromide was 1 mg / mL.

[0101] S4, 80 μL of a perovskite precursor solution containing 2-(4-fluorophenyl)ethylamine hydrobromide was spin-coated onto the surface of the hole transport layer: First, spin-coating was performed at a low speed of 2500 rpm for 30 seconds. Then, spin-coating was performed at a high speed of 5500 rpm for 15 seconds; and 300 μL of the anti-solvent chlorobenzene was added dropwise during the 1-2 s of high-speed spin-coating. Afterwards, the mixture was annealed at 100°C for 20 minutes to form the perovskite light-absorbing layer.

[0102] In step S5, a 15 nm thick layer of C60 is deposited on the surface of the perovskite light-absorbing layer, followed by the deposition of a 15 nm thick layer of SnOx using ALD (Atomic Layer Deposition). This forms an electron transport layer.

[0103] S6. Electrode layer is prepared on electron transport layer: IZO with a thickness of 30nm is sputtered by magnetron sputtering equipment, and then the silver electrode is deposited on the surface of IZO by evaporation in high vacuum through a vapor deposition machine to obtain metal electrode with a thickness of 210nm.

[0104] In the preparation process of Example 1-1 above, after step S4, XRD was performed on the perovskite light-absorbing layer, and the obtained XRD pattern can be found in [reference needed]. Figure 1 The B-map in the image.

[0105] Examples 1-2 The difference from Example 1-1 is as follows: If the step of adding 2-(4-fluorophenyl)ethylamine hydrobromide to the perovskite precursor solution in step S3 is removed, then the solute of the perovskite precursor solution is composed of the perovskite precursor.

[0106] The process following S4 and preceding S5 includes a passivation layer preparation step: 2-(4-fluorophenyl)ethylamine hydrobromide is dissolved in isopropanol to prepare a passivation solution with a 2-(4-fluorophenyl)ethylamine hydrobromide concentration of 1.5 mg / mL; 80 μL of the passivation solution is spin-coated onto the perovskite light-absorbing layer obtained in S4 at a speed of 4000 rpm / s. Then, the layer is annealed at 65°C for 5 minutes to obtain the passivation layer.

[0107] The remaining steps and parameters are the same as in Example 1-1.

[0108] Examples 1-3 The difference from Example 1-1 is as follows: After step S4 and before step S5, a passivating agent preparation step is included: 2-(4-fluorophenyl)ethylamine hydrobromide is dissolved in isopropanol to prepare a passivation solution with a 2-(4-fluorophenyl)ethylamine hydrobromide concentration of 1.5 mg / mL; 80 μL of the passivation solution is spin-coated onto the perovskite light-absorbing layer obtained in S4 at a speed of 4000 rpm / s. Then, it is annealed at 65°C for 5 minutes to form a two-dimensional layer.

[0109] The remaining steps and parameters are the same as in Example 1-1.

[0110] In the preparation process of Examples 1-3 above, before step S5, XRD was performed on the two-dimensional layer on the perovskite light-absorbing layer, and the obtained XRD pattern can be found in [reference]. Figure 1 The C-map in the image.

[0111] Examples 1-4 Fabrication of positive perovskite solar cells: First, an electron transport layer is formed on an ITO glass substrate, then a perovskite light-absorbing layer is formed, and finally a hole transport layer is formed on the perovskite light-absorbing layer.

[0112] The difference from Example 1-1 is that S2 involves preparing the electron transport layer: a 15% SnO2 aqueous solution is diluted with ultrapure water at a volume ratio of SnO2 to water of 1:3. The diluted solution is then sonicated at 90 Hz for 30 min to form a SnO2 solution. 80 μL of the SnO2 solution is spin-coated onto ITO at 4000 rpm / s to form the electron transport layer.

[0113] S5 is for preparing the hole transport layer: Take 17.5 μL of the prepared lithium salt acetonitrile solution (concentration 520 mg·mL). -1The solution was mixed with 29 μL of tBP (4-tert-butylpyridine), and 73.5 mg of spiro-OMeTAD (2,2',7,7'-Tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene, 2,2',7,7'-tetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene) powder was added to the mixture, along with 1 mL of chlorobenzene to completely dissolve it, forming a spiro-OMeTAD solution. 80 μL of the spiro-OMeTAD solution was then spin-coated onto a perovskite light-absorbing layer at 4000 rpm / s to form a hole transport layer.

[0114] The remaining steps and parameters are the same as in Example 1-1 to obtain a positive perovskite solar cell.

[0115] Examples 1-5 The difference from Example 1-1 is that the annealing temperature in step S4 is 110°C.

[0116] Examples 1-6 The difference from Examples 1-3 is that the annealing temperature of the passivating agent spin coating step is 90°C.

[0117] Examples 1-7 The difference from Example 1-1 is that the molar ratio of 2-(4-fluorophenyl)ethylamine hydrobromide to lead ions in the perovskite precursor solution in step S3 is 0.00076.

[0118] Examples 1-8 The difference from Examples 1-3 is that the annealing temperature of the passivating agent spin coating step is 100°C.

[0119] Examples 1-9 The difference from Examples 1-3 is that the annealing temperature of the passivating agent spin coating step is 50°C.

[0120] Comparative Example 1-1 Compared to Example 1-1, the difference is that the step of adding 2-(4-fluorophenyl)ethylamine hydrobromide to the perovskite precursor solution in step S3 is removed, and the solute of the perovskite precursor solution is composed of the perovskite precursor.

[0121] The remaining steps and parameters are the same as in Example 1-1.

[0122] In the preparation process of Comparative Example 1-1, after step S4, XRD was performed on the perovskite light-absorbing layer. The obtained XRD pattern can be found in [link to XRD pattern]. Figure 1 The A-map in the image.

[0123] Comparative Examples 1-2 Compared to Comparative Example 1-1, the difference lies in the following: after step S2 and before step S3, the method further includes: dissolving 2-(4-fluorophenyl)ethylamine hydrobromide in isopropanol to prepare a passivation solution with a concentration of 1.5 mg / mL of 2-(4-fluorophenyl)ethylamine hydrobromide; taking 80 μL of the passivation solution and spin-coating it onto the hole transport layer obtained in S2 at a speed of 4000 rpm / s. Then, annealing is performed at 65°C for 5 minutes.

[0124] The remaining steps and parameters are the same as those in Comparative Example 1-1.

[0125] In the preparation process of Comparative Examples 1-2, after step S4, XRD was performed on the perovskite light-absorbing layer, and the obtained XRD pattern can be found in [link to XRD pattern]. Figure 1 The D-map in the image.

[0126] Comparative Examples 1-3 Compared to Examples 1-4, the difference is that the step of adding 2-(4-fluorophenyl)ethylamine hydrobromide to the perovskite precursor solution in step S3 is removed, so the solute of the perovskite precursor solution is composed of the perovskite precursor.

[0127] The remaining steps and parameters are the same as in Examples 1-4.

[0128] Furthermore, the perovskite solar cells in the above embodiments and comparative examples were tested under the following conditions: AM1.5G, 100mW / cm². 2 Temperature: 25℃. The test results of the perovskite solar cells in each embodiment and comparative example are shown in Table 1.

[0129] Table 1

[0130] According to Table 1, the photoelectric conversion efficiency of perovskite solar cells can be improved by using a two-dimensional layer above the perovskite light-absorbing layer. In particular, the photoelectric conversion efficiency is optimal in Examples 1-3, where the perovskite material precursor solution contains 2-(4-fluorophenyl)ethylamine hydrobromide and the passivation solution also contains 2-(4-fluorophenyl)ethylamine hydrobromide.

[0131] Comparing Examples 1-3, 1-6, 1-8, and 1-9, it can be seen that when the passivating agent annealing temperature is less than or equal to 100°C, while a two-dimensional layer is formed on the perovskite light-absorbing layer, bromide ions in 2-(4-fluorophenyl)ethylamine hydrobromide can effectively fill the bromide ion vacancies in the perovskite light-absorbing layer, thereby improving the photoelectric conversion efficiency of the perovskite solar cell.

[0132] Comparing Examples 1-1 and 1-7, it can be seen that when the molar ratio of 2-(4-fluorophenyl)ethylamine hydrohalate in the perovskite precursor solution to the molar ratio of B ions in the perovskite material is less than 0.001, the photoelectric conversion efficiency of the perovskite solar cell shows a significant decrease. Therefore, it can be concluded that only when the molar ratio of 2-(4-fluorophenyl)ethylamine hydrohalate in the perovskite precursor solution to the molar ratio of B ions in the perovskite material is greater than or equal to 0.001 can a two-dimensional layer that effectively promotes its performance enhancement be formed above the perovskite light-absorbing layer.

[0133] As can be seen from the comparison of Examples 1-4 and Comparative Examples 1-3, in the embodiments of this application, the two-dimensional layer-aligned perovskite solar cell disposed above the perovskite light-absorbing layer can also improve its photoelectric conversion efficiency.

[0134] Finally, comparing Comparative Examples 1-1 and 1-2, it can be seen that after spin-coating 2-(4-fluorophenyl)ethylamine hydrohalate as an additive onto the hole transport layer, and then proceeding with the steps related to the preparation of the perovskite light-absorbing layer, 2-(4-fluorophenyl)ethylamine hydrohalate did not participate in the crystallization of the perovskite material precursor during the preparation process. Instead, it led to a decrease in the photoelectric conversion efficiency and other performance characteristics of the perovskite solar cell.

[0135] Furthermore, in the preparation process of the aforementioned embodiments and comparative examples, after step S4, XRD was performed on the perovskite light-absorbing layer to obtain XRD patterns corresponding to Examples 1-1, as detailed in [link to example]. Figure 1 The B-pattern in the image corresponds to the XRD patterns of the passivation layer tested in Examples 1-3; please refer to the details. Figure 1 The C-plot in [the image / database]. And the XRD plot corresponding to Comparative Example 1-1, please see [the image / database]. Figure 1 The A spectrum in the figure corresponds to the XRD patterns in Comparative Examples 1-2; please see the details below. Figure 1 The D-map in the image. For example... Figure 1 As shown, spectrum A does not contain diffraction peaks of the two-dimensional layer; spectrum B contains diffraction peaks of the two-dimensional layer. To clearly observe the positions of the diffraction peaks of the two-dimensional layer in spectrum B, a local magnification was applied to the area between 6° and 10° in spectrum B, as shown below. Figure 2 As shown, a two-dimensional diffraction peak appears at position 8° in the B spectrum. This means that when 2-(4-fluorophenyl)ethylamine hydrohalate is added as an additive to the perovskite precursor solution, a two-dimensional phase is formed above the perovskite light-absorbing layer, which is at least a discontinuous two-dimensional layer.

[0136] observe Figure 1 The C-ray diffraction pattern shows obvious diffraction peaks in the two-dimensional layer, indicating that the content and thickness of the two-dimensional layer in Examples 1-3 are relatively high, and the photoelectric conversion efficiency is the best in Examples 1-3.

[0137] Continue to observeFigure 1 No diffraction peaks corresponding to the two-dimensional layer were observed in the D-spectrum. This indicates that no two-dimensional layer was formed in the corresponding comparative examples 1-2.

[0138] The following provides examples and comparative models of stacked solar cells for further explanation: Example 2-1 The difference from Example 1-1 is as follows: S1. Ethanol is spin-coated onto the transparent conductive layer (TCO) of the crystalline silicon bottom cell at a spin coater at a speed of 3000 rpm for 30s, and this process is repeated twice. Then, the cell is heat-treated at 200℃ for 10 min to complete the cleaning. The crystalline silicon bottom cell with the N-side facing up and without a silver electrode is subjected to ultraviolet ozone for 15 minutes. The crystalline silicon bottom cell includes an N-type monocrystalline silicon substrate, a P-type amorphous silicon thin film (P-side) deposited on the front side of the N-type monocrystalline silicon substrate and a silver electrode, an N-type amorphous silicon thin film (N-side) deposited on the back side of the N-type monocrystalline silicon substrate, and a transparent conductive layer (TCO) deposited on the N-type amorphous silicon thin film (N-side).

[0139] The Me-2PACz solution in S2 was spin-coated onto the transparent conductive layer on the N-side of the crystalline silicon bottom cell. The spin-coating process parameters were as follows: spin-coating at 3000 rpm for 30 seconds, followed by annealing at 100°C for 10 minutes to prepare the hole transport layer.

[0140] The remaining steps and parameters are the same as in Example 1-1, resulting in a crystalline silicon / perovskite tandem solar cell.

[0141] Example 2-2 This corresponds to the crystalline silicon / perovskite tandem solar cells of Examples 1-2. The difference from Examples 1-2 is: S1. Ethanol is spin-coated onto the transparent conductive layer (TCO) of the crystalline silicon bottom cell at a spin coater at a speed of 3000 rpm for 30s, and this process is repeated twice. Then, the cell is heat-treated at 200℃ for 10 min to complete the cleaning. The crystalline silicon bottom cell with the N-side facing up and without a silver electrode is subjected to ultraviolet ozone for 15 minutes. The crystalline silicon bottom cell includes an N-type monocrystalline silicon substrate, a P-type amorphous silicon thin film (P-side) deposited on the front side of the N-type monocrystalline silicon substrate and a silver electrode, an N-type amorphous silicon thin film (N-side) deposited on the back side of the N-type monocrystalline silicon substrate, and a transparent conductive layer (TCO) deposited on the N-type amorphous silicon thin film (N-side).

[0142] In S2, the Me-2PACz solution is spin-coated onto the transparent conductive layer on the N-side of the crystalline silicon bottom cell. The spin-coating process parameters are: spin-coating at 3000 rpm for 30 seconds, followed by annealing at 100°C for 10 minutes to form a hole transport layer.

[0143] The remaining steps and parameters are the same as in Examples 1-2.

[0144] Example 2-3 This corresponds to the crystalline silicon / perovskite tandem solar cells of Examples 1-3. The difference from Examples 1-3 is: S1. Ethanol is spin-coated onto the transparent conductive layer (TCO) of the crystalline silicon bottom cell at a spin coater at a speed of 3000 rpm for 30s, and this process is repeated twice. Then, the cell is heat-treated at 200℃ for 10 min to complete the cleaning. The crystalline silicon bottom cell with the N-side facing up and without a silver electrode is subjected to ultraviolet ozone for 15 minutes. The crystalline silicon bottom cell includes an N-type monocrystalline silicon substrate, a P-type amorphous silicon thin film (P-side) deposited on the front side of the N-type monocrystalline silicon substrate and a silver electrode, an N-type amorphous silicon thin film (N-side) deposited on the back side of the N-type monocrystalline silicon substrate, and a transparent conductive layer (TCO) deposited on the N-type amorphous silicon thin film (N-side).

[0145] The Me-2PACz solution in S2 was spin-coated onto the transparent conductive layer on the N-side of the crystalline silicon bottom cell. The spin-coating process parameters were: spin-coating at 3000 rpm for 30 seconds, followed by annealing at 100°C for 10 minutes to form a hole transport layer.

[0146] The remaining steps and parameters are the same as in Examples 1-3.

[0147] Comparative Example 2-1 Compared to Comparative Example 1-1, the crystalline silicon / perovskite tandem solar cell differs in that: S1. Ethanol is spin-coated onto the transparent conductive layer (TCO) of the crystalline silicon bottom cell at a spin coater at a speed of 3000 rpm for 30s, and this process is repeated twice. Then, the cell is heat-treated at 200℃ for 10 min to complete the cleaning. The crystalline silicon bottom cell with the N-side facing up and without a silver electrode is subjected to ultraviolet ozone for 15 minutes. The crystalline silicon bottom cell includes an N-type monocrystalline silicon substrate, a P-type amorphous silicon thin film (P-side) deposited on the front side of the N-type monocrystalline silicon substrate and a silver electrode, an N-type amorphous silicon thin film (N-side) deposited on the back side of the N-type monocrystalline silicon substrate, and a transparent conductive layer (TCO) deposited on the N-type amorphous silicon thin film (N-side).

[0148] The Me-2PACz solution in S2 was spin-coated onto the transparent conductive layer on the N-side of the crystalline silicon bottom cell. The spin-coating process parameters were: spin-coating at 3000 rpm for 30 seconds, followed by annealing at 100°C for 10 minutes to form a hole transport layer.

[0149] The remaining steps and parameters are the same as those in Comparative Example 1-1.

[0150] Comparative Example 2-2 Compared to Comparative Examples 1-2, the crystalline silicon / perovskite tandem solar cells differ in that: S1. Ethanol is spin-coated onto the transparent conductive layer (TCO) of the crystalline silicon bottom cell at a spin coater at a speed of 3000 rpm for 30s, and this process is repeated twice. Then, the cell is heat-treated at 200℃ for 10 min to complete the cleaning. The crystalline silicon bottom cell with the N-side facing up and without a silver electrode is subjected to ultraviolet ozone for 15 minutes. The crystalline silicon bottom cell includes an N-type monocrystalline silicon substrate, a P-type amorphous silicon thin film (P-side) deposited on the front side of the N-type monocrystalline silicon substrate and a silver electrode, an N-type amorphous silicon thin film (N-side) deposited on the back side of the N-type monocrystalline silicon substrate, and a transparent conductive layer (TCO) deposited on the N-type amorphous silicon thin film (N-side).

[0151] The Me-2PACz solution in S2 was spin-coated onto the transparent conductive layer on the N-side of the crystalline silicon bottom cell. The spin-coating process parameters were: spin-coating at 3000 rpm for 30 seconds, followed by annealing at 100°C for 10 minutes to form a hole transport layer.

[0152] The remaining steps and parameters are the same as those in Comparative Example 1-2.

[0153] Comparative Examples 2-3 The crystalline silicon / perovskite tandem solar cells correspond to Examples 1-7. The difference from Examples 1-7 is: S1. Ethanol is spin-coated onto the transparent conductive layer (TCO) of the crystalline silicon bottom cell at a spin coater at a speed of 3000 rpm for 30s, and this process is repeated twice. Then, the cell is heat-treated at 200℃ for 10 min to complete the cleaning. The crystalline silicon bottom cell with the N-side facing up and without a silver electrode is subjected to ultraviolet ozone for 15 minutes. The crystalline silicon bottom cell includes an N-type monocrystalline silicon substrate, a P-type amorphous silicon thin film (P-side) deposited on the front side of the N-type monocrystalline silicon substrate and a silver electrode, an N-type amorphous silicon thin film (N-side) deposited on the back side of the N-type monocrystalline silicon substrate, and a transparent conductive layer (TCO) deposited on the N-type amorphous silicon thin film (N-side).

[0154] The Me-2PACz solution in S2 was spin-coated onto the transparent conductive layer on the N-side of the crystalline silicon bottom cell. The spin-coating process parameters were: spin-coating at 3000 rpm for 30 seconds, followed by annealing at 100°C for 10 minutes to form a hole transport layer.

[0155] The remaining steps and parameters are the same as in Examples 1-7.

[0156] The crystalline silicon / perovskite tandem solar cells in the above embodiments and comparative examples were tested, and the test results are shown in Table 2.

[0157] Table 2

[0158] As shown in Table 2, in the embodiments of this application, the two-dimensional layer above the perovskite light-absorbing layer provides the same performance improvement for the tandem solar cell as the aforementioned single-junction solar cell. Comparing Examples 2-1 to 2-3, it can be seen that the performance of the two-dimensional layer is optimal when both the perovskite precursor solution and the passivation solution contain 2-(4-fluorophenyl)ethylamine hydrohalate. Further comparison of Examples 2-1 and 2-3 shows that when the molar ratio of 2-(4-fluorophenyl)ethylamine hydrohalate in the perovskite precursor solution to the molar ratio of B ions in the perovskite material is less than 0.001, the photoelectric conversion efficiency of the tandem solar cell exhibits a significant decrease.

[0159] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A perovskite solar cell, comprising a substrate, a first carrier transport layer, a perovskite light-absorbing layer, and a second carrier transport layer stacked sequentially, characterized in that, The perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and an additive; wherein the additive is 2-(4-fluorophenyl)ethylamine hydrohalate. or, It also includes a passivation layer disposed between the perovskite light-absorbing layer and the second carrier transport layer; the perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and the additive, and / or the passivation layer is prepared from a passivation solution containing at least 2-(4-fluorophenyl)ethylamine hydrohalate.

2. The perovskite solar cell according to claim 1, characterized in that, The perovskite light-absorbing layer contains a perovskite material with the chemical formula ABX3, where A is at least one monovalent cation, B is at least one divalent metal ion, and X is a halide ion. In the case where the perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and an additive, the molar ratio of the additive to the molar ratio of B ions in the perovskite material is 0.001 to 0.05:

1.

3. A perovskite solar cell according to claim 2, characterized in that, In ABX3, A is FA. + MA + and Cs + At least one of them, B is Pb 2+ and / or Sn 2+ X contains at least Br - Or I - ; And / or, The solvent for the perovskite precursor solution is a mixture of DMF and DMSO.

4. A perovskite solar cell according to claim 2 or 3, characterized in that, In the case where the perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and additives, The additives added to the perovskite precursor solution include 2-(4-fluorophenyl)ethylamine hydrobromide and / or 2-(4-fluorophenyl)ethylamine hydroiodide. And / or, The concentration of the additive in the mixed solution is less than or equal to 5 mg / mL; And / or, The thickness of the perovskite light-absorbing layer is 500~900nm.

5. A perovskite solar cell according to claim 1, characterized in that, In the case where the passivation layer is prepared from a passivation solution containing at least 2-(4-fluorophenyl)ethylamine hydrohalate, The 2-(4-fluorophenyl)ethylamine hydrohalate in the passivation solution includes 2-(4-fluorophenyl)ethylamine hydrobromide and / or 2-(4-fluorophenyl)ethylamine hydroiodide; And / or, The concentration of the 2-(4-fluorophenyl)ethylamine hydrohalate in the passivation solution is less than or equal to 5 mg / mL; And / or, The thickness of the passivation layer is 10~100nm.

6. A method for fabricating a perovskite solar cell, comprising sequentially fabricating a first carrier transport layer, a perovskite light-absorbing layer, and a second carrier transport layer stacked on a substrate, characterized in that, The preparation of the perovskite light-absorbing layer includes: A mixed solution containing a perovskite material precursor solution and additives is coated onto the first carrier transport layer and then annealed to form the perovskite light-absorbing layer. The additive is 2-(4-fluorophenyl)ethylamine hydrohalate.

7. The method for preparing a perovskite solar cell according to claim 6, characterized in that, The concentration of the additive in the mixed solution is 0.5~3 mg / mL; And / or, During the preparation of the perovskite light-absorbing layer, the annealing temperature is 90~120℃; And / or, The thickness of the prepared perovskite light-absorbing layer is 500~900 nm.

8. A method for fabricating a perovskite solar cell, comprising sequentially fabricating a first carrier transport layer, a perovskite light-absorbing layer, a passivation layer, and a second carrier transport layer stacked on a substrate, characterized in that, The preparation of the perovskite light-absorbing layer includes: coating a mixed solution containing a perovskite material precursor solution and an additive onto the first carrier transport layer, and annealing the solution to form the perovskite light-absorbing layer on the first carrier transport layer; wherein the additive is 2-(4-fluorophenyl)ethylamine hydrohalate. And / or, The preparation of the passivation layer includes: coating the perovskite light-absorbing layer with a passivation solution containing at least 2-(4-fluorophenyl)ethylamine hydrohalate, and annealing the solution to form the passivation layer on the perovskite light-absorbing layer.

9. The method for preparing a perovskite solar cell according to claim 8, characterized in that, In the case where the perovskite light-absorbing layer is prepared from a mixed solution containing a perovskite material precursor solution and an additive, the concentration of the additive in the mixed solution is 0.5~3 mg / mL; In the case where the passivation layer is prepared from a passivation solution containing at least 2-(4-fluorophenyl)ethylamine hydrohalate, the concentration of 2-(4-fluorophenyl)ethylamine hydrohalate in the passivation solution is 0.1~3 mg / mL.

10. A method for preparing a perovskite solar cell according to claim 8 or 9, characterized in that, During the preparation of the perovskite light-absorbing layer, the annealing temperature is 90~120℃; during the preparation of the passivation layer, the annealing temperature is 50~90℃. And / or, The thickness of the perovskite light-absorbing layer prepared is 500~900 nm; the thickness of the passivation layer prepared is 10~100 nm.

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