A / m / x crystal material, photovoltaic device and preparation method thereof

Abstract

The application provides an A / M / X crystal material, a photovoltaic device and a preparation method thereof. The A / M / X crystal material comprises a photoactive crystal material layer; the photoactive crystal material layer comprises through grains, the through grains are grains penetrating through the photoactive crystal material layer, and the percentage p of the number of the through grains to the total number of grains in the photoactive crystal material layer is greater than or equal to 80%; and the photoactive crystal material layer comprises a back light side and back light grains, the back light grains are grains exposed to the back light side, and the back light grains have back light crystal faces exposed to the back light side; wherein at least one region of the back light side has an average flatness coefficient R avg ≤75.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to an A / M / X crystal material, a photovoltaic device, and a method for preparing the same. Background Technology

[0002] Perovskite photovoltaic devices are a type of photovoltaic device that uses photoactive perovskite structural materials as the photoactive crystal material layer for photoelectric conversion.

[0003] Typical photoactive perovskite structural materials are organometal halides with the general formula AMX3, and are generally octahedral or cubic structures. In a typical perovskite crystal, the A ion is located at the center of the cubic unit cell and is labeled by 12 X ions to form a coordinated chiral octahedron, resulting in a three-dimensional periodic structure; the M ion is located at the corner vertices of the cubic unit cell, surrounded by 6 X ions coordinated to form an octahedral symmetric structure.

[0004] Photoactive perovskite materials, under light radiation, generate two types of charge carriers: electrons and holes. These electrons and holes are collected through two electrodes, generating a photocurrent. The properties of the perovskite structure are a key factor affecting the power conversion efficiency (PCE) of photovoltaic devices. Summary of the Invention

[0005] The purpose of this application is to provide a photovoltaic device with higher energy conversion efficiency.

[0006] A first aspect of this application provides a photovoltaic device, including a photoactive crystal material layer, the photoactive crystal material layer including a first region; In the first region, the photoactive crystal material layer includes penetrating grains, which are grains that penetrate the photoactive crystal material layer. The percentage of the number of penetrating grains to the total number of grains in the photoactive crystal material layer is p ≥ 80%, optionally, p ≥ 90%; and In the first region, the photoactive crystal material layer includes a backlight side and a backlight grain, wherein the backlight grain is a grain with at least one side exposed to the backlight side, and the side of the backlight grain exposed to the backlight side is a backlight crystal surface. The backlight side has an average flatness coefficient R. avg R avg ≤75, optionally 10≤R avg ≤70; Among them, the R on the backlight side avg Calculated using the following formula: ; Among them, R i R is the flatness coefficient of the i-th backlight chip in the first region. i Calculated using the following formula: R i =d i / h i Where, d i The width of the backlight crystal plane of the i-th backlight crystal in the first region; Among them, h i The convex height of the backlight crystal surface of the i-th backlight crystal in the first region; Where n is the total number of backlight chips in the first region.

[0007] Photovoltaic devices based on the above scheme have improved energy conversion efficiency.

[0008] In some embodiments, the photoactive crystal material includes an A / M / X crystal material, which has the following general formula: [A] a [M] b [X] c [M] includes one or more first cations, wherein the first cation includes metal ions, quasi-metal ions, or combinations thereof; [A] includes one or more second cations; [X] includes one or more halide anions; a can be 1 to 6, and optionally, a can be 1, 2, 3, 4, 5 or 6; b can be 1 to 6, or optionally b can be 1, 2, 3, 4, 5 or 6; c can be 1 to 18, or optionally 3, 6, 9, or 18.

[0009] Photovoltaic devices based on the above scheme have improved energy conversion efficiency.

[0010] In some embodiments, the one or more first cations are selected from Ca. 2+ 、Sr 2+ Cd 2+ Cu 2+ Ni 2+ Mn 2 +、 Fe 2+ Co 2+ Pd 2+ 、Ge 2+ Sn 2+、 Pb 2+ Yb 2+ Eu 2+ Bi3+, Sb3+, Pd 4+ W 4+ Re 4+ Os4+ Ir 4+ Pt 4+ Sn 4+ Pb 4+ 、Ge 4+ Or Te 4+ .

[0011] Optionally, the one or more first cations are selected from Cu. 2+ Pb 2+ 、Ge 2+ or Sn 2+ ; (2) The one or more second cations are selected from Cs + 、(NR 1 R 2 R 3 R 4 ) + 、(R 1 R 2 N=CR 3 R 4 ) + 、(R 1 R 2 NC(R 5 )=NR 3 R 4 ) + or (R) 1 R 2 NC(NR 5 R 6 )=R 3 R 4 ) + , where R 1 , R 2 , R 3 , R 4 , R 5 and R 6 Each is independently selected from H, substituted or unsubstituted C. 1-20 Alkyl or substituted or unsubstituted aryl; Optionally, the one or more second cations are selected from Cs. + (CH3NH3) + (H2N-C(H)=NH2) + (3) The halogen anion is selected from Cl. - ,Br - or I - .

[0012] Photovoltaic devices based on the above scheme have improved energy conversion efficiency.

[0013] In some embodiments, said A / M / X crystalline material comprises FAPbI3, FAPbBr3, FAPbCl3, FAPbF3, FAPbBr. x I 3-x 、FAPbBr x Cl 3-x 、FAPbI x Br 3-x 、FAPbI x Cl 3-x 、FAPbCl x Br 3-x 、FAPbI 3-x Cl x 、CsPbI3、CsPbBr3、CsPbCl3、CsPbF3、CsPbBr x I 3-x 、CsPbBr x Cl 3-x 、CsPbI x Br 3-x 、CsPbI x Cl 3-x 、CsPbCl x Br 3-x 、CsPbI 3-x Cl x 、FA 1-y Thursday y PbI3、FA 1-y Thursday y PbBr3、FA 1-y Thursday y PbCl3、FA 1-y Thursday y PbF3、FA 1-y Thursday y PbBr x I 3-x 、FA 1- y Thursday y PbBr x Cl 3-x 、FA 1-y Thursday y PbI x Br 3-x 、FA 1-y Thursday y PbI x Cl 3-x 、FA 1-y Thursday y PbCl x Br 3-x 、FA 1-y Thursday y PbI3-x Cl x or a combination thereof; Where x = 0 - 3, y = 0.01 - 0.25.

[0014] Photovoltaic devices based on the above scheme have improved energy conversion efficiency.

[0015] In some embodiments, the A / M / X crystal material includes FAPbI3, CsPbI3, and FA. 1-y Cs y PbI3, or combinations thereof, where y = 0.01-0.25.

[0016] Photovoltaic devices based on the above scheme have improved energy conversion efficiency.

[0017] In some embodiments, the thickness of the photoactive crystal material layer is 100 nm or more, and can be selected as 100 nm-1000 nm or 300 nm-700 nm.

[0018] Photovoltaic devices based on the above scheme have improved energy conversion efficiency.

[0019] In some embodiments, the photovoltaic device further includes a first charge transport layer and a second charge transport layer, with the photoactive crystal material layer located between the first charge transport layer and the second charge transport layer; The first charge transport layer and the second charge transport layer are respectively the electron transport layer and the hole transport layer, or The first charge transport layer and the second charge transport layer are a hole transport layer and an electron transport layer, respectively.

[0020] In some embodiments, the photovoltaic device further includes a first electrode and a second electrode, wherein the electron transport layer, the hole transport layer and the photoactive crystal material layer are located between the first electrode and the second electrode; Optionally, the first electrode comprises a transparent conductive oxide; Optionally, the second electrode comprises a metal.

[0021] Photovoltaic devices based on the above scheme have improved energy conversion efficiency.

[0022] A second aspect of this application provides a method for preparing an A / M / X crystal material, wherein the A / M / X crystal material has the following general formula: [A] a [M] b [X] c [M] includes one or more first cations, wherein the first cation includes metal ions, quasi-metal ions, or combinations thereof; [A] includes one or more second cations; [X] includes one or more halide anions; a can be 1 to 6, for example, a = 1; b can be 1 to 6, for example, b=1; c can be 1 to 18, for example, c=3; The method includes setting a precursor composition on a matrix, the precursor composition comprising the following components: (a) At least one precursor compound; (b) Solvent; (c) Surfactants; and (d) Amino compounds.

[0023] The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0024] In some embodiments, the surfactant includes an amphoteric surfactant. The A / M / X crystalline material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0025] In some embodiments, the amino compound includes: nitrile amine compounds, amino acid compounds (e.g., aminosulfonic acid compounds), hydrazine compounds, urea compounds (e.g., urea, urea-formaldehyde, biuret, triuret), guanidine compounds, or their salts or hydrates. The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0026] In some embodiments, the surfactant includes dodecylaminopropionate, dodecylethoxysulfonate, dodecyldimethylhydroxypropylsulfonate, zwitterionic polyacrylamide, octadecyl dihydroxyethylamine oxide, tetradecyl dihydroxyethylamine oxide, lauramide propylamine oxide, dodecyl betaine, L-α-phosphocholine, 3-(N,N-dimethyltetradecylammonium)propane sulfonate, dodecylbenzene sulfonate, or combinations thereof. A / M / X crystal materials prepared based on the above schemes are used in photovoltaic devices, which exhibit improved power conversion efficiency.

[0027] In some embodiments, the amino compound includes: urea-formaldehyde (C3H8N2O3), isobutylidene diurea (C6H... 14 The A / M / X crystal materials prepared based on the above schemes are used in photovoltaic devices, which exhibit improved energy conversion efficiency. These devices utilize N4O2, hydrazine (H4N2), guanidine (CH3N3O), nitrileamine (CH2N2), aminosulfonic acid (H3NO3S), or combinations thereof.

[0028] In some embodiments, the precursor composition includes a first solvent and a second solvent, wherein the first solvent has a boiling point of 40°C-165°C, and the second solvent has a boiling point of 170°C-250°C. The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0029] In some embodiments, the first solvent is selected from one or more of N,N-dimethylformamide (DMF), 2-methoxyethanol, and acetonitrile (ACN). The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0030] In some embodiments, the second solvent is selected from one or more of dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and diphenyl sulfoxide (DPSO). The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0031] In some embodiments, the volume ratio of the first solvent to the second solvent is (4-10):1. The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0032] In some embodiments, the precursor composition comprises: A first precursor compound, the first precursor compound containing a first cation; and The second precursor compound contains a second cation.

[0033] The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0034] In some embodiments, the first precursor compound contains a halide anion. The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0035] In some embodiments, the second precursor compound contains a halide anion. The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved power conversion efficiency.

[0036] In some embodiments, the first compound includes lead iodide (PbI2), lead bromide (PbBr2), or a combination thereof; In some embodiments, the second compound includes formamidine hydroiodide (FAI), formamidine hydrobromide (FABr), cesium iodide (CsI), cesium bromide (CsBr), or combinations thereof.

[0037] The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0038] In some embodiments, the method for preparing A / M / X crystalline materials further includes a step of curing a precursor composition disposed on a substrate surface; Optionally, the curing process includes: vacuum treatment, air blading, infrared light treatment, or a combination thereof. The A / M / X crystal material prepared based on the above method is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0039] In some embodiments, the method for preparing A / M / X crystal materials further includes annealing the cured product; Optionally, the annealing temperature is 100°C - 170°C; Optionally, the annealing process takes 5-60 minutes.

[0040] The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0041] A third aspect of this application provides a method for fabricating a photovoltaic device, the photovoltaic device comprising a first electrode and a second electrode, a first charge transport layer and a second charge transport layer located between the first electrode and the second electrode, and an A / M / X crystal material layer located between the first charge transport layer and the second charge transport layer. The method includes: A first electrode having a first charge transport layer disposed on its surface is provided; The method for preparing A / M / X crystal material according to any one of the above claims forms the A / M / X crystal material layer on the surface of the first charge transport layer; A second charge transport layer is formed on the A / M / X crystal material layer; A second electrode is formed on the second charge transport layer; Wherein, the first charge transport layer and the second charge transport layer are respectively the electron transport layer and the hole transport layer, or The first charge transport layer and the second charge transport layer are a hole transport layer and an electron transport layer, respectively.

[0042] The photovoltaic devices prepared based on the above scheme have improved energy conversion efficiency.

[0043] Beneficial effects One or more of the technical solutions in this application exhibit one or more of the following beneficial effects: (1) Photovoltaic devices exhibit significantly enhanced power conversion efficiency (PCE); (2) The photoactive crystal material layer has a high proportion of through-grains p; (3) The photoactive crystal material layer has a low average flatness coefficient R avg ; (4) Surfactants and nitrogen-containing compounds played an unexpected synergistic effect in the method of preparing photoactive crystal layers; (5) The preparation method is low in cost, high in efficiency and easy to scale up. Attached Figure Description

[0044] Figure 1 A schematic diagram of a photovoltaic device according to some embodiments of this application is shown; Figure 2 Schematic diagrams showing photoactive crystal material layers in some embodiments of this application; Figure 3 (a) and (b) respectively show schematic diagrams of photoactive crystal material layers of some embodiments and comparative embodiments of this application; Figure 4 Scanning electron microscope images of intermediate products containing photoactive crystal material layers according to some embodiments of this application are shown.

[0045] Figure label explanation: Substrate 106, first electrode 105, first charge transport layer 104, photoactive crystal material layer 103, second charge transport layer 102, second electrode 101; through-grain (313); backlight grains (31, 32, 33), width d of the backlight grains i The protrusion height h of the backlight grain i 113 (backlight side); Incident light 151, reflected light 152, light-receiving surface 112, grain boundary 325. Detailed Implementation

[0046] The embodiments of the A / M / X crystal material, photovoltaic device, and fabrication method thereof of this application are disclosed in detail below with appropriate reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of actually identical structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0047] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0048] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0049] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0050] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, for example, sequentially. For instance, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For instance, the mention that the method may also include step (c), indicating that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0051] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0052] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0053] Photovoltaic devices Photovoltaic devices (also known as photovoltaic cells or solar cells) are devices used to convert solar energy into electrical energy.

[0054] Figure 1 A schematic diagram of a photovoltaic device according to some embodiments of this application is shown; Figure 2 A schematic diagram of a photoactive crystal material layer is shown in some embodiments of this application.

[0055] refer to Figure 1-2 In some embodiments, this application provides a photovoltaic device including a photoactive crystal material layer 103, the photoactive crystal material layer 103 including a first region; In the first region, the photoactive crystal material layer 103 includes penetrating crystals 313, which are crystals that penetrate the photoactive crystal material layer 103. The percentage of the number of penetrating crystals 313 to the total number of crystals in the photoactive crystal material layer 103 is p≥80%, optionally p≥90%, optionally p≥95%, optionally p≥99%, and optionally p=100%. In the first region, the photoactive crystal material layer 103 includes a backlight side 113 and backlight crystals (31, 32, 33). The backlight crystals (31, 32, 33) are crystals with at least one surface exposed to the backlight side 113, and the surface of the backlight crystals (31, 32, 33) exposed to the backlight side 113 is called the backlight crystal face. The backlight side 113 has an average flatness coefficient R. avg (Average Flatness Index), R avg ≤75, optionally 10≤R avg ≤70, optional R avg The values ​​are 1-10, 10-20, 20-30, 30-40, 40-50, 50-60, or 60-70; Among them, the R of the backlight side 113 avg Calculated using the following formula: ; Among them, R i R is the flatness coefficient of the i-th backlight chip (31,32,33) in the first region. i Calculated using the following formula: R i =d i / h i Where, d i The width of the backlight crystal plane of the i-th backlight crystal (31,32,33) in the first region; Among them, h i The convex height of the backlight crystal surface of the i-th backlight crystal (31,32,33) in the first region; Where n is the total number of all backlight chips (31, 32, 33) in the first region.

[0056] In the above-described scheme, the inventors unexpectedly discovered that by optimizing the grain shape and arrangement of the photoactive crystal material layer, the energy conversion efficiency of the photovoltaic device can be significantly improved. Specifically, the inventors found that when the percentage p of the number of penetrating grains 313 in the photoactive crystal material layer 103 to the total number of grains ≥ 80%, and simultaneously, the average flatness coefficient R of the backlight grains (31, 32, 33) in at least a portion of the backlight side of the photoactive crystal material layer is ≥ 80%, avg When the value is ≤75, the photovoltaic device exhibits a significantly enhanced power conversion efficiency (PCE).

[0057] refer to Figure 2 In some implementations, the average flatness factor R avg The measurement and calculation scheme in Figure 2 Detailed description is provided. Figure 2 A crystalline material layer 103 is shown. The photoactive crystalline material layer 103 includes a backlight side 113 and backlight grains (31, 32, 33). The backlight grains (31, 32, 33) are grains exposed on the backlight side 113, and the backlight grains (31, 32, 33) have backlight crystal faces exposed on the backlight side. Among them, the R of the backlight side 113 avg Calculated using the following formula: ; Among them, R i R is the flatness coefficient of the i-th backlight chip (31,32,33) in the first region. i Calculated using the following formula: R i =d i / h i Where, d i Let d1, d2, d3 be the width of the backlight crystal plane of the i-th backlight crystal (31, 32, 33) in the first region. Among them, h i The convex height (h1, h2, h3) of the backlight crystal surface of the i-th backlight crystal (31, 32, 33) in the first region. Where n is the total number of all backlight chips (31, 32, 33) in the first region; for Figure 2 In the region of the photoactive crystal layer 103 shown, the total number of backlighting grains (31, 32, 33) is n=3, therefore, the value of i ranges from 1 to 3.

[0058] In some implementations, n takes the value of 3 or higher, for example, 5 or higher, 10 or higher, 50 or higher, 100 or higher, 500 or higher, or 1000 or higher.

[0059] refer to Figure 3 , Figure 3 (a) and (b) show schematic diagrams of two photoactive crystalline material layers, respectively.

[0060] refer to Figure 3Figure (a) shows a schematic diagram of the first photoactive crystal material layer. As shown, the percentage p = 100% of the total number of grains in the first photoactive crystal material layer 103 is the number of through-grains 313. Incident light 151 enters from the light-receiving surface 112 of the first photoactive crystal material layer. Since the grains of the first photoactive crystal material layer are through-grains 313, the incident light 151 can reach the backlight surface 113 almost unobstructed, which allows the first photoactive crystal material layer to be fully radiated by the incident light 151.

[0061] refer to Figure 3 Figure (b) shows a schematic diagram of a contrast photoactive crystal material layer. As shown, all grains of this contrast photoactive crystal material layer are non-penetrating grains 323, and the percentage of penetrating grains in the total number of grains of the photoactive crystal material layer 103 is p=0%. Incident light 151 enters from the light-receiving surface 112 of the contrast photoactive crystal material layer. Since all grains of the contrast photoactive crystal material layer 313 are non-penetrating grains 323, the incident light 151 is reflected or refracted by the grain boundaries 325 before reaching the backlight surface 113. This results in the contrast photoactive crystal material layer not being able to fully absorb the radiant energy of the incident light 151.

[0062] The flatness factor is a coefficient that measures the flatness of a grain's surface. A higher flatness factor indicates that the back facet of the grain is approximately flat, while a lower flatness factor indicates that the back facet of the grain is more convex.

[0063] refer to Figure 3 In (a), the backlight grains (31, 32, 33) of the first photoactive crystal material layer have a low flatness coefficient (≤75), meaning the ratio (d / h) of the bandwidth to the protrusion height of the backlight grains (31, 32, 33) is low. The backlight grains (31, 32, 33) have protruding surfaces, which allows the backlight side 113 of the photoactive crystal material layer to concentrate most of the reflected light 152 within the first photoactive crystal material layer, rather than reflecting it outwards. This enables the first photoactive crystal material layer to fully utilize light energy.

[0064] See again Figure 3 (b) Figure 3 Figure (b) shows a schematic diagram of a contrast photoactive crystal material layer. As shown, the backlight grains (31, 32, 33) of this contrast photoactive crystal material layer have a high flatness factor (>1000), meaning that the backlight grains (31, 32, 33) have flat backlight crystal surfaces. This flat backlight surface will reflect most of the reflected light 152 outside the layer, which makes it impossible for the contrast photoactive crystal material layer 312 to fully utilize light energy.

[0065] In some embodiments, the first region refers to part or all of the region of the photoactive crystal layer 103 along the surface direction.

[0066] In some embodiments, the first region has a size of 3 μm or more in at least one direction, for example, 10 μm or more, 100 μm or more, 1 mm or more, 1 cm or more, or 10 cm or more. Optionally, the first region has a size of 3 × 3 μm or more in at least two mutually perpendicular directions, for example, 10 × 10 μm or more, 100 × 100 μm or more, 1 × 1 mm or more, 1 × 1 cm or more, 10 × 10 cm or more, or 1 m × 1 m or more.

[0067] In some embodiments, the total number of grains in the first region of the photoactive crystal layer is 9 or more (3×3), for example 16 or more (4×4), for example 25 or more (5×5), for example 64 or more (8×8), for example 100 or more (10×10), for example 1000 or more.

[0068] In some implementations, the area of ​​the first region is equivalent to more than 10%, such as more than 50%, more than 70%, more than 90%, or more than 100% of the area of ​​one side of the photoactive crystal layer.

[0069] In some embodiments, the photoactive crystal layer 103 includes a plurality of grains. A grain penetrating the photoactive crystal material layer 103 is a penetrating grain 313. A grain with at least one side exposed to the backlight side 113 is a backlight grain (31, 32, 33). It should be understood that a grain may belong to both the penetrating grain 313 and the backlight grain (31, 32, 33). Alternatively, a grain may belong only to the backlight grain (31, 32, 33) and not to the penetrating grain 313.

[0070] In some implementations, the term "crystal" refers to a crystalline compound, which is a compound having an extended 3D crystalline structure. Crystalline compounds typically exist in the form of crystals, or, in the case of polycrystalline compounds, in the form of microcrystals (i.e., multiple crystals having a particle size of less than or equal to 1 μm). Crystals together often form layers. The crystals of crystalline materials can be of any size. When crystals have dimensions in the range of 1 nm to 1000 nm in one or more dimensions, they can be called nanocrystals.

[0071] In some embodiments, the term "layer" refers to any structure that is substantially layered (e.g., extending substantially in two perpendicular directions, but with its extension limited in a third perpendicular direction). A layer may have a thickness that varies within the range of its extension. Typically, the thickness of a layer is approximately constant. As used herein, "thickness" of a layer refers to the average thickness of the layer. The thickness of a layer can be readily measured, for example by microscopy, such as electron microscopy of a thin film cross-section, or by surface profilometry, such as using a stylus profilometer.

[0072] In some implementations, the term "light-receiving surface" refers to the surface of the photovoltaic device facing the light source when it is operating; the term "backlight surface" refers to the surface of the photovoltaic device facing away from the light source when it is operating.

[0073] In some embodiments, the term "grain" as used in this application refers to a "single crystal grain." For example, one grain refers to one single crystal grain; the number of grains refers to the number of single crystal grains. The term "single crystal grain" can be defined as "a single crystal body of crystalline material that contains no large-angle boundaries or twinboundaries," as described in ASTM F1241.

[0074] In some implementations, the term "through" refers to the distance from one side of the photoactive crystal layer to the other, such as from the light-receiving side to the back-lighting side.

[0075] In some implementations, the protrusion height of the backlit crystal facet is obtained by observing and measuring a cross-section of the photoactive crystal material layer using a photomicrograph. In the aforementioned cross-sectional photomicrograph, the height by which the contour of the backlit crystal facet protrudes relative to the backlit base surface is defined as the protrusion height of the backlit crystal facet; the width by which the contour of the backlit crystal facet protrudes relative to the backlit base surface is defined as the width of the backlit crystal facet. The backlit base surface refers to a continuous, substantially flat surface that substantially penetrates the lowest point of each backlit crystal facet.

[0076] In some embodiments, the photoactive crystal material includes an A / M / X crystal material, which has the following general formula: [A] a [M] b [X] c [M] includes one or more first cations, wherein the first cation includes metal ions, quasi-metal ions, or combinations thereof; [A] includes one or more second cations; [X] includes one or more halide anions; a can be 1 to 6, and optionally, a can be 1, 2, 3, 4, 5 or 6; b can be 1 to 6, or optionally b can be 1, 2, 3, 4, 5 or 6; c can be 1 to 18, and optionally, c can be 3, 6, 9, or 18. Based on the above scheme, the photovoltaic device has improved energy conversion efficiency.

[0077] In some embodiments, the one or more first cations are selected from Ca. 2+ 、Sr 2+ Cd 2+ Cu 2+ Ni 2+ Mn 2 +、 Fe 2+ Co 2+ Pd 2+ 、Ge 2+ Sn 2+、 Pb 2+ Yb 2+ Eu 2+ Bi3+, Sb3+, Pd 4+ W 4+ Re 4+ Os 4+ Ir 4+ Pt 4+ Sn 4+ Pb 4+ 、Ge 4+ Or Te 4+ Based on the above scheme, photovoltaic devices have improved energy conversion efficiency.

[0078] In some embodiments, the one or more first cations are selected from Cu. 2+ Pb 2+ 、Ge 2+ or Sn 2+ Based on the above scheme, photovoltaic devices have improved energy conversion efficiency.

[0079] In some embodiments, the one or more second cations are selected from Cs. + 、(NR 1 R 2 R 3 R 4 ) + 、(R 1 R 2 N=CR 3 R 4 ) + 、(R 1 R 2NC(R 5 )=NR 3 R 4 ) + or (R) 1 R 2 NC(NR 5 R 6 )=R 3 R 4 ) + , where R 1 , R 2 , R 3 , R 4 , R 5 and R 6 Each is independently selected from H, substituted or unsubstituted C. 1-20 Alkyl groups or substituted or unsubstituted aryl groups. Based on the above scheme, photovoltaic devices have improved energy conversion efficiency.

[0080] In some embodiments, the one or more second cations are selected from Cs. + (CH3NH3) + (H2N-C(H)=NH2) + Based on the above scheme, photovoltaic devices have improved energy conversion efficiency.

[0081] In some embodiments, the halide anion is selected from Cl. - ,Br - or I - Based on the above scheme, photovoltaic devices have improved energy conversion efficiency.

[0082] In some embodiments, the A / M / X crystal material includes FAPbI3, FAPbBr3, FAPbCl3, FAPbF3, and FAPbBr. x I 3-x ,FAPbBr x Cl 3-x ,FAPbI x Br 3-x ,FAPbI x Cl 3-x ,FAPbCl x Br 3-x ,FAPbI 3-x Cl x , CsPbI3, CsPbBr3, CsPbCl3, CsPbF3, CsPbBr x I 3-x CsPbBr x Cl 3-x CsPbI x Br 3-xCsPbI x Cl 3-x CsPbCl x Br 3-x CsPbI 3-x Cl x FA 1-y Cs y PbI3, FA 1-y Cs y PbBr3, FA 1-y Cs y PbCl3, FA 1-y Cs y PbF3, FA 1-y Cs y PbBr x I 3-x FA 1- y Cs y PbBr x Cl 3-x FA 1-y Cs y PbI x Br 3-x FA 1-y Cs y PbI x Cl 3-x FA 1-y Cs y PbCl x Br 3-x FA 1-y Cs y PbI 3-x Cl x or a combination thereof; Where x = 0-3 and y = 0.01-0.25. Based on the above scheme, the photovoltaic device has improved energy conversion efficiency.

[0083] In some embodiments, the A / M / X crystal material includes FAPbI3, CsPbI3, and FA. 1-y Cs y PbI3, or combinations thereof, where y = 0.01-0.25. Based on the above scheme, the photovoltaic device has improved energy conversion efficiency.

[0084] In some embodiments, the A / M / X crystal material is a perovskite material. Optionally, the A / M / X crystal material is a metal halide perovskite. The term "metal halide perovskite" refers to a perovskite containing at least one metal cation and at least one halide anion. Optionally, the A / M / X crystal material is a mixed halide perovskite. The term "mixed halide perovskite" refers to a perovskite or mixed perovskite containing at least two types of halide anions. Optionally, the A / M / X crystal material is a mixed cation perovskite. The term "mixed cation perovskite" refers to a perovskite containing at least two types of A cations. Based on the above schemes, the photovoltaic device has improved power conversion efficiency.

[0085] In some embodiments, the term "perovskite" refers to a material having a three-dimensional crystal structure associated with the three-dimensional crystal structure of CaTiO3, or comprising a layered material having a structure associated with the structure of CaTiO3. A material having a three-dimensional crystal structure associated with CaTiO3 may be referred to as a perovskite having a "3D perovskite structure," or simply "3D perovskite." The structure of CaTiO3 can be represented by the formula AMX3, where A and M are cations of different sizes, and X is an anion. In the unit cell, cation A is located at (0, 0, 0), cation M at (1 / 2, 1 / 2, 1 / 2), and anion X at (1 / 2, 1 / 2, 0). Cation A is typically larger than cation M. Those skilled in the art will understand that as A, M, and X vary, different ion sizes may cause the structure of the perovskite material to distort from the structure adopted by CaTiO3 to a distorted structure with lower symmetry. Materials comprising layers of perovskite material are well known. For example, materials employing the K2NiF4-type structure include perovskite material layers. These are referred to in the art as “2D layered perovskites” and are structurally different from the 3D perovskites described above. 2D layered perovskites can be represented by the formula [A]2[M][X]4, where [A] is at least one cation, [M] is at least one cation of a different size from the cation [A], and [X] is at least one anion.

[0086] In some embodiments, the thickness of the photoactive crystal material layer is 100 nm or more, optionally 100-1000 nm, or optionally 300-700 nm. Based on the above scheme, the photovoltaic device has improved energy conversion efficiency.

[0087] In some embodiments, the photovoltaic device further includes a first charge transport layer 104 and a second charge transport layer 102, wherein the photoactive crystal material layer 103 is located between the first charge transport layer 104 and the second charge transport layer 102. The first charge transport layer 104 and the second charge transport layer 102 are respectively the electron transport layer and the hole transport layer, or The first charge transport layer 104 and the second charge transport layer 102 are a hole transport layer and an electron transport layer, respectively. Based on the above scheme, the photovoltaic device has improved energy conversion efficiency.

[0088] In some embodiments, the photovoltaic device further includes a first electrode 105 and a second electrode 101, wherein the electron transport layer, the hole transport layer and the photoactive crystal material layer are located between the first electrode 105 and the second electrode 101. Optionally, the first electrode 105 comprises a transparent conductive oxide; Optionally, the second electrode 101 comprises metal. Based on the above scheme, the photovoltaic device has improved energy conversion efficiency.

[0089] In some embodiments, this application also provides a method for preparing an A / M / X crystal material, wherein the A / M / X crystal material has the following general formula: [A] a [M] b [X] c [M] includes one or more first cations, wherein the first cation includes metal ions, quasi-metal ions, or combinations thereof; [A] includes one or more second cations; [X] includes one or more halide anions; a can be 1 to 6, for example, a = 1; b can be 1 to 6, for example, b=1; c can be 1 to 18, for example, c=3.

[0090] The method includes setting a precursor composition on a matrix, the precursor composition comprising the following components: (a) At least one precursor compound; (b) Solvent; (c) Surfactants; and (d) Amino compounds (Organic nitrogen-containing compounds).

[0091] In the above-mentioned scheme, the inventors unexpectedly discovered that by combining a surfactant with an amino compound in the precursor composition for preparing A / M / X crystal materials, the prepared A / M / X crystal materials have both a high proportion of through-grains and a low flatness coefficient. These A / M / X crystal materials are used in photovoltaic devices, which have improved energy conversion efficiency.

[0092] In some embodiments, the concentration of at least one precursor compound in the precursor composition is 0.5 mol / L to 2.5 mol / L, for example, 0.5 mol / L to 1.5 mol / L or 1.5 mol / L to 2.5 mol / L.

[0093] In some embodiments, the concentration of the surfactant in the precursor composition is 0.05 wt%-0.5 wt%, for example 0.1 wt%-0.2 wt%, 0.2 wt%-0.3 wt%, 0.3 wt%-0.4 wt%, or 0.4 wt%-0.5 wt%.

[0094] In some embodiments, the concentration of the amino compound in the precursor composition is 1wt%-10wt%, for example 2wt%-4wt%, 4wt%-6wt%, 6wt%-8wt%, or 8wt%-10wt%.

[0095] In some implementations, the term "surfactant" refers to any amphiphilic compound (molecule or ion) comprising both hydrophilic and lipophilic portions. Surfactants typically function by accumulating at the oil-water interface, causing the hydrophilic portion to oriented towards the aqueous phase and the lipophilic portion towards the hydrophobic phase, thereby reducing surface tension. Suitable surfactants include water-insoluble surfactants, water-dispersible surfactants, and water-soluble surfactants.

[0096] In some embodiments, the surfactant includes an amphoteric surfactant.

[0097] The term "amphoteric surfactant" refers to a compound having both a cationic and anionic centers attached to the same molecule. Specifically, the cationic moiety is based on a primary, secondary, or tertiary amine, or a quaternary ammonium cation. The anionic moiety includes, but is not limited to, carboxylates, sulfonates, and phosphates. More specifically, the "amphoteric surfactant" refers to an N- group having a functional group bonded to C(O)O-, SO3H, or SO3-. + -O-Sensitive Group, Season N + Compounds with functional groups, and compounds having tertiary N functional groups that are combined with C(O)OH, C(O)O-, SO3H or SO3- functional groups.

[0098] For a review of amphoteric surfactants and their properties, see Amphoteric Surfactants, 2nd ed., EGLomax, ed., 1996, Marcel Dekker. These surfactants include betaines, such as fatty alkyl betaines, fatty alkylamide betaines, sulfobetaines, hydroxysulfobetaines, and betaines derived from imidazolines; amine oxides, such as fatty alkylamine oxides and fatty alkylamide amine oxides; amphoteric glycinates and amphoteric propionates; and so-called “balanced” amphoteric polycarboxylated glycinates and amphoteric polycarboxylated propionates.

[0099] In some embodiments, the amino compound includes: amino nitrile compounds, amino acid compounds, hydrazine compounds, urea compounds (e.g., urea, urea-formaldehyde, biuret, triuret), guanidine compounds, or their salts or hydrates.

[0100] In some embodiments, the term "amino compounds" refers to any compound containing at least one primary, secondary, tertiary, or quaternary ammonium group.

[0101] In some embodiments, the amino compounds are C1-C20 compounds, such as C1-C15 compounds, such as C1-C10 compounds, such as C1-C5 compounds, and C15-C20 compounds.

[0102] In some embodiments, the term "aminonitrile compound" refers to a compound containing at least one "amino-methyl-cyano" group. Optional "aminonitrile compounds" include aminonitrile (AAN), iminodiacetonitrile (IDAN), or ethylenediaminediacetonitrile (EDN).

[0103] In some implementations, the term "amino acid" refers to a molecule having at least one amino group and at least one carboxyl group.

[0104] In some embodiments, the term "aminosulfonic acid compound" refers to a molecule containing at least one amino group and at least one sulfonyl group.

[0105] In some implementations, the term "hydrazine compounds" includes hydrazine and substituted hydrazine.

[0106] In some embodiments, substitution means that the H atom of the substituted compound is replaced by one or more of the following groups: alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl, and heterocyclic. In some implementations, the term "urea compound" refers to compounds having -NR1 R 2 -C(=S)-NR 3 R 4 Compounds with - groups, each R 1 R 2 R 3 and R 4 The compounds are independently selected from H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl, and heterocyclic groups. Optional urea compounds include urea (urea), thiourea, urea-formaldehyde, biuret, triuret, and their substituted derivatives.

[0107] In some embodiments, the surfactant includes dodecylaminopropionate, dodecylethoxysulfonate, dodecyldimethylhydroxypropylsulfonate, zwitterionic polyacrylamide, octadecyl dihydroxyethylamine oxide, tetradecyl dihydroxyethylamine oxide, lauramide propylamine oxide, dodecyl betaine, L-α-phosphocholine, 3-(N,N-dimethyltetradecylammonium)propane sulfonate, dodecylbenzene sulfonate, or combinations thereof. Based on the above schemes, the photovoltaic device has improved energy conversion efficiency. The A / M / X crystal material prepared based on the above schemes is used in photovoltaic devices, and the photovoltaic device has improved energy conversion efficiency.

[0108] In some embodiments, the surfactant includes dodecyl betaine, 3-(N,N-dimethyltetradecylammonium)propane sulfonate, lauroamide propylamine oxide, L-α-phosphocholine, or combinations thereof. The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0109] In some embodiments, the amino compounds include: urea-formaldehyde (C3H8N2O3), isobutylidene diurea (C6H... 14 The photovoltaic device uses N4O2, hydrazine (H4N2), guanidine (CH3N3O), cyanamide (CH2N2), aminosulfonic acid (H3NO3S), or combinations thereof. Based on the above scheme, the photovoltaic device exhibits improved energy conversion efficiency. The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, resulting in improved energy conversion efficiency.

[0110] In some embodiments, the amino compounds include guanidine, aminosulfonic acid, urea, or combinations thereof. The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0111] In some embodiments, the precursor composition includes a first solvent and a second solvent; the first solvent has a boiling point of 40°C-165°C (e.g., 40°C-60°C, 60°C-80°C, 80°C-100°C, 100°C-120°C, 120°C-140°C, or 140°C-160°C); and the second solvent has a boiling point of 170°C-250°C (e.g., 170°C-190°C, 190°C-210°C, 210°C-230°C, or 230°C-250°C). In this approach, combining a first solvent with a specific boiling point and a second solvent with a specific boiling point can effectively improve the film coverage and crystal quality of the A / M / X crystal material.

[0112] In some embodiments, the first solvent is selected from one or more of N,N-dimethylformamide (DMF), 2-methoxyethanol, and acetonitrile (ACN). The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0113] In some embodiments, the second solvent is selected from one or more of dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and diphenyl sulfoxide (DPSO). The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0114] In some embodiments, the volume ratio of the first solvent to the second solvent is (4-10):1. Combining a first solvent with a specific boiling point and a second solvent with a specific boiling point in the above-mentioned specific ratio can effectively improve the film coverage and crystal quality of A / M / X crystal materials.

[0115] In some embodiments, the precursor composition includes A first precursor compound, the first precursor compound containing a first cation; and A second precursor compound, containing a second cation. The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0116] In some embodiments, the first precursor compound contains a halide anion. The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0117] In some embodiments, the second precursor compound contains a halide anion. The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0118] In some embodiments, the first compound includes lead iodide (PbI2), lead bromide (PbBr2), or a combination thereof. The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0119] In some embodiments, the second compound includes formamidinium hydroiodate (FAI), formamidinium hydrobromide (FABr), cesium iodide (CsI), cesium bromide (CsBr), or combinations thereof. The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved power conversion efficiency.

[0120] In some embodiments, the method for preparing A / M / X crystalline materials further includes a step of curing a precursor composition disposed on a substrate surface; Optionally, the curing process includes: vacuum treatment, air blading, infrared light treatment, or a combination thereof. The A / M / X crystal material prepared based on the above methods is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0121] In some embodiments, the method for preparing A / M / X crystal materials further includes annealing the cured product. A / M / X crystal materials prepared based on the above methods are used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0122] In some embodiments, the annealing temperature is 100°C-170°C (e.g., 100°C-120°C, 120°C-140°C, 140°C-160°C, or 160°C-170°C). The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0123] In some embodiments, the annealing time is 5 min-60 min (e.g., 5 min-15 min, 15 min-25 min, 25 min-35 min, 35 min-45 min, or 45 min-55 min). The A / M / X crystal material prepared based on the above scheme is used in photovoltaic devices, which exhibit improved energy conversion efficiency.

[0124] In some embodiments, this application also provides a method for fabricating a photovoltaic device, the photovoltaic device including a first electrode 105 and a second electrode 101, a first charge transport layer 104 and a second charge transport layer 102 located between the first electrode 105 and the second electrode 101, and an A / M / X crystal material layer located between the first charge transport layer 104 and the second charge transport layer 102. The method includes: A first electrode 105 having a first charge transport layer 104 disposed on its surface is provided; The method for preparing A / M / X crystal material according to any of the above claims forms the A / M / X crystal material layer on the surface of the first charge transport layer 104; A second charge transport layer 102 is formed on the A / M / X crystal material layer; A second electrode 101 is formed on the second charge transport layer 102; Wherein, the first charge transport layer 104 and the second charge transport layer 102 are respectively the electron transport layer and the hole transport layer, or The first charge transport layer 104 and the second charge transport layer 102 are a hole transport layer and an electron transport layer, respectively. The photovoltaic device fabricated based on the above scheme has improved energy conversion efficiency.

[0125] In some implementations, the photovoltaic device may include the following layers in the following order: • First electrode (e.g., comprising a transparent conductive oxide); • First charge transport material layer (e.g., hole transport material layer); • Photoactive crystal material layer; • Second charge transport material layer (e.g., electron transport material layer); • A second electrode (e.g., comprising an elemental metal). Photovoltaic devices fabricated based on the above scheme exhibit improved energy conversion efficiency.

[0126] In some implementations, the photovoltaic device may include the following layers in the following order: • First electrode (e.g., comprising a transparent conductive oxide); • First charge transport material layer (e.g., electron transport material layer); • Photoactive crystal material layer; • A second charge transport material layer (e.g., a hole transport material layer); • A second electrode (e.g., comprising an elemental metal). Photovoltaic devices fabricated based on the above scheme exhibit improved energy conversion efficiency.

[0127] [Photoactive Crystal Material Layer] In some implementations, "photoactive crystal material" refers to a material that can absorb light and subsequently generate free charge carriers (such as electrons and holes).

[0128] In some embodiments, photoactive crystal materials are generally capable of absorbing and / or emitting photons in the visible region of the spectrum, such as photons in the blue light region of the visible spectrum. Therefore, photoactive crystal materials can be described as light-emitting materials (i.e., materials that emit light) or light-absorbing materials (i.e., materials that absorb light). For example, photoactive crystal materials may emit and / or absorb at least one type of photon with a wavelength in the range of 450 to 700 nm, such as 450 to 650 nm.

[0129] In some embodiments, the photoactive crystal material may include 5 wt% or more of A / M / X crystal material. For example, the photoactive crystal material may include 80 wt% or more of A / M / X crystal material, such as 95 wt% or more of A / M / X crystal material, or 99 wt% or more of A / M / X crystal material. The photoactive crystal material may consist of or be substantially composed of A / M / X crystal material.

[0130] In some embodiments, the photoactive crystal material is, for example, a solid.

[0131] In some embodiments, the photoactive crystal material layer comprises a thin film of A / M / X crystal material. Typically, the A / M / X crystal material is polycrystalline, therefore the photoactive crystal material accordingly comprises polycrystalline A / M / X crystal material.

[0132] In some embodiments, the photoactive crystal material layer may include multiple layers. Some or all of each layer may include A / M / X crystal materials.

[0133] In some embodiments, the A / M / X crystal material may be uniformly or non-uniformly distributed throughout the photoactive crystal material layer. For example, the photoactive crystal material may comprise a layer consisting essentially of or solely of the A / M / X crystal material. Alternatively or additionally, the photoactive crystal material may comprise the substrate having the A / M / X crystal material on it (e.g., in powder or thin film form).

[0134] [Electron transport layer] In some embodiments, the electron transport layer is a layer containing an electron transport material (also known as an n-type semiconductor material). The electron transport material can be a single electron transport compound or elemental material, or a mixture of two or more electron transport compounds or elemental materials. The electron transport compound or elemental material can be undoped or doped with one or more doping elements.

[0135] Examples of electron transport materials are known to those skilled in the art.

[0136] Electron transport materials may include fullerenes or fullerene derivatives, such as C60, C70, PCBM, PC71BM, bis[C60]BM (i.e., bis-C60-methyl butyrate), and ICBA (CAS: 1207461-57-1). Electron transport materials may include organic electron transport materials, such as perylene or its derivatives, P(NDI2OD-T2) (CAS: 1100243-40-0) or copper bath (BCP).

[0137] Electron transport materials can include inorganic electron transport materials, such as metal oxides, metal sulfides, metal selenides, metal tellurides, perovskites, amorphous silicon, n-type group IV semiconductors, n-type group III-V semiconductors, n-type group II-VI semiconductors, n-type group I-VII semiconductors, n-type group IV-VI semiconductors, n-type group V-VI semiconductors, and n-type group II-V semiconductors, any of which can be doped or undoped.

[0138] Hole transport layer In some implementations, a hole transport layer refers to a layer containing hole transport (also known as p-type semiconductor material) material.

[0139] Examples of hole transport materials are known to those skilled in the art. Hole transport materials can be a single hole transport compound or elemental material, or a mixture of two or more hole transport compounds or elemental materials. Hole transport compounds or elemental materials can be undoped or doped with one or more dopant elements.

[0140] Organic hole transport materials may include, for example, spiro-OMeTAD, P3HT, PCPDTBT, poly-TPD, spiro-ring (TFSI)2, and PVK.

[0141] Inorganic hole transport materials may include oxides of nickel (e.g., NiO), vanadium, copper, or molybdenum; CuI, CuBr, CuSCN, Cu2O, CuO, or CIS; perovskite; amorphous silicon; p-type group IV semiconductors, p-type group III-V semiconductors, p-type group II-VI semiconductors, p-type group I-VII semiconductors, p-type group IV-VI semiconductors, p-type group V-VI semiconductors, and p-type group II-V semiconductors. These inorganic materials may be doped or undoped.

[0142] [electrode] The term "electrode" refers to a region or layer that is composed of or is substantially composed of electrode material.

[0143] The photovoltaic device of this application may further include a first electrode and a second electrode.

[0144] The first electrode may include a metal (e.g., silver, gold, aluminum, or tungsten), an organic conductive material such as PEDOT:PSS, or a transparent conductive oxide (e.g., fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), or indium-doped tin oxide (ITO)). Typically, the first electrode is a transparent electrode. Therefore, the first electrode typically comprises a transparent conductive oxide, such as FTO, ITO, or AZO. The thickness of the first electrode layer is, for example, from 10 nm to 1000 nm, or more specifically, from 40 nm to 400 nm.

[0145] The second electrode can be defined as described above for the first electrode. For example, the second electrode can include a metal (e.g., silver, gold, aluminum, or tungsten), an organic conductive material (e.g., PEDOT:PSS), or a transparent conductive oxide (e.g., fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), or indium-doped tin oxide (ITO)). Typically, the second electrode comprises a metal (e.g., an elemental metal) or is substantially composed of a metal (e.g., an elemental metal). Examples of second electrode materials that can be metals or substantially composed of metals include silver, gold, copper, aluminum, platinum, palladium, or tungsten. The second electrode can be formed by vacuum evaporation. The thickness of the second electrode material layer is, for example, 10 to 1000 nm, such as 50 nm to 150 nm.

[0146] [Example] The technical solutions of this application are described in detail below with reference to specific embodiments and comparative examples. Unless otherwise specified, the reagents, methods, and equipment used in this application are conventional food-grade reagents, methods, and equipment in the art. Unless otherwise specified, the experimental conditions used in the embodiments of this application are conventional experimental conditions in the art. Unless otherwise specified, all reagents used in the embodiments of this application are commercially available.

[0147] The CAS numbers for some raw materials and reagents are as follows: CAS 3-(N,N-dimethyltetradecylammonium)propane sulfonate 14933-09-6 dodecyl betaine 683-10-3 Lauroamide propylamine oxide 61792-31-2 L-α-phosphatidylcholine 8002-43-5 Example 1 refer to Figure 1 As shown by the arrow in the figure, the photovoltaic device of Embodiment 1 includes a substrate 106, a first electrode 105, a first charge transport layer 104, a photoactive crystal material layer 103, a second charge transport layer 102, and a second electrode 101 stacked sequentially.

[0148] The method for fabricating the photovoltaic device in Example 1 is as follows: (1) A perovskite precursor solution was prepared by dissolving 1362 mg formamidinium hydroiodate (FAI), 228.6 mg cesium iodide (CsI), and 4056.9 mg lead iodide (PbI2) in 8 mL of solvent, wherein the molar concentration of FAI was 0.99 mol / L, the molar concentration of CsI was 0.11 mol / L, and the molar concentration of PbI2 was 1.1 mol / L. The solvent was a mixture of DMF (N,N-dimethylformamide) and NMP (N-methylpyrrolidone) in a volume ratio of 7:1. Then, a surfactant and a nitrogen-containing compound were added to the above solvent, with a weight percentage of 0.1 wt% and 5 wt%, respectively. In Example 1, the surfactant was dodecyl betaine, and the nitrogen-containing compound was urea.

[0149] (2) Provide a 2cm × 2cm FTO conductive glass (FTO conductive glass is glass with an FTO conductive layer on its surface; FTO is an abbreviation for Fluorine Doped Tin Oxide). The FTO conductive glass includes a glass plate and an FTO conductive layer deposited on the glass plate. Using a laser engraving technique, a 0.66cm wide section of the FTO conductive layer at the two opposite edges of the FTO conductive glass is removed, leaving a 2cm × 1.34cm FTO conductive layer on the FTO conductive glass. Here, the glass plate serves as the substrate 106, and the FTO conductive layer serves as the first electrode 105.

[0150] (3) A first charge transport layer 104 (nickel oxide layer) is formed on the first electrode 105 (FTO conductive layer) using magnetron sputtering technology. The thickness of the nickel oxide layer is about 20 nm. The first charge transport layer 104 serves as a hole transport layer here.

[0151] (4) The precursor solution was coated onto the nickel oxide layer. The sample was then transferred to a vacuum chamber and held at a vacuum level below 100 Pa for 120 seconds to allow the precursor solution to solidify into a film. The solidified sample was then placed on a hot plate for annealing at 150°C for 30 minutes. After annealing, a good A / M / X crystalline material layer was formed on the nickel oxide layer. In this embodiment, the composition of the A / M / X crystalline material is FA. 0.9 Cs 0.1 The PbI3.A / M / X crystalline material layer serves as the photoactive crystalline material layer 103 here.

[0152] (6) The sample obtained in the previous step is placed in a vapor deposition system to deposit a second charge transport layer 102 on the photoactive crystal material layer 103. Here, the second charge transport layer 102 is an electron transport layer. The second charge transport layer includes a 30 nm thick C layer formed by sequential vapor deposition.60 (Fullerene) layer and 8nm thick BCP (bathocuproine) layer.

[0153] (7) Still in the above-described vapor deposition system, a second electrode 101 is formed on the second charge transport layer 102. The second electrode 101 is a 100 nm thick copper layer, and the photovoltaic device of Example 1 is obtained.

[0154] Examples 2-4 The difference between Examples 2-4 and Example 1 lies in the different types of surfactants and / or nitrogen-containing compounds in the precursor solutions.

[0155] For a detailed comparison of surfactants and nitrogen-containing compounds, please refer to Table 1.

[0156] Comparative Examples 1-8 The difference between Comparative Example 1 and Example 1 is that the precursor solution does not contain surfactants and nitrogen-containing compounds.

[0157] The difference between Comparative Examples 2-8 and Example 1 lies in the fact that the precursor solutions do not contain surfactants and the types or amounts of nitrogen-containing compounds are different.

[0158] For a detailed comparison of surfactants and nitrogen-containing compounds, please refer to Table 1.

[0159] Analysis and testing 1. Morphological characteristics: (1) Sample preparation: According to the scheme of Example 4, implement steps (1) to (4) and use the product of step (6) as the observation sample. Use a glass cutter to make a straight scratch on one side of the glass plate of the observation sample, and then break the photovoltaic device along the scratch to expose the cross-section.

[0160] (2) Sample observation: The cross-section was observed using a scanning electron microscope (SEM), and photographs were taken at a magnification of 30,000x. The photographs are shown below. Figure 4 As shown. The observed sample includes a substrate 106, a first electrode 105 stacked on the substrate 106, a first charge transport layer 104 stacked on the first electrode 105, and a photoactive crystal material layer 103 stacked on the first charge transport layer 104.

[0161] (3) Crystal morphology of the photoactive crystal material layer like Figure 4 As shown, within the photographed area, the cross-sectional length of the photoactive crystal material layer 103 is 3.7 μm, and the total number of complete grains in this area is 4.

[0162] First, the photoactive crystal material layer 103 includes penetrating grains 313, which are grains that penetrate the photoactive crystal material layer 103. The number of penetrating grains 313 is 4, accounting for a percentage of 100% of the total number of grains in the photoactive crystal material layer 103.

[0163] Second, the photoactive crystal material layer 103 includes a backlight side 113 and backlight grains, wherein the backlight grains are grains exposed on the backlight side 113 and the backlight grains have a backlight crystal surface exposed on the backlight side 113. Within the photographic area, the backlit side has an average flatness coefficient R. avg =11.4; Among them, the R area of ​​the photo avg Calculated using the following formula: ; Among them, R i R is the flatness coefficient of the i-th backlight grain within the image region. i Calculated using the following formula: R i =d i / h i Where, d i Let be the width of the backlight crystal plane of the i-th backlight crystal (31,32,33) within the image area; Among them, h i Let be the protrusion height of the backlight crystal surface of the i-th backlight crystal (31,32,33) within the image area; Where n is the total number of backlighting crystals in the region, n=4.

[0164] The products obtained in step (6) of Examples 1-4 and Comparative Examples 1-8 were observed using scanning electron microscopy. A cross-section of the photoactive crystal material layer with a length of 3.7 μm was collected, and the following calculations were performed: (1) The percentage p of the total number of grains in the photoactive crystal material layer, where the 313 penetrating grains are located; (2) The backlight side has an average flatness coefficient R avg .

[0165] For detailed results, please refer to Table 1.

[0166] 2. Energy conversion efficiency characterization The photovoltaic devices obtained from the schemes of Examples 1-4 and Comparative Examples 1-8, under standard simulated sunlight (AM 1.5G, 100 mW / cm²), 2The power conversion efficiency (PCE) of photovoltaic devices was tested under irradiation. For specific test methods, please refer to the literature Stabilizing perovskite-substrate interfaces for high-performance perovskite modules, Science 373, 902 (2021). The test results are detailed in Table 1.

[0167] Table 1

[0168] Analysis conclusion: (1) About photovoltaic devices The photovoltaic devices in Examples 1-4 have a power conversion efficiency of 20.1%-21.1%, which is significantly higher than that in Comparative Examples 1-8, which is only 16%-18.9%.

[0169] The significantly improved energy conversion efficiency of the photovoltaic devices in Examples 1-4 is attributed to the fact that the photoactive crystal layer of the photovoltaic device simultaneously satisfies the following characteristics a) and b). a) The percentage of penetrating grain 313 in the total number of grains in the photoactive crystal material layer is p ≥ 80, for example, reaching p = 100; and b) The backlight side has an average flatness coefficient R avg ≤75, for example, reaching R avg =11.4-59.

[0170] (2) Regarding the synergistic effect of surfactants and nitrogen-containing compounds Compared to Comparative Examples 1-8, the precursor solutions of Examples 1-4 contained, in addition to the precursor compounds, surfactants and nitrogen-containing compounds.

[0171] This application reveals that obtaining a 313-p-permeable grain with a proportion p ≥ 80% and an average flatness coefficient R... avg A photoactive crystal material layer with a density ≤75 is difficult to obtain. As shown in Comparative Examples 1-8, it is impossible to obtain a transmembrane grain 313 ratio p≥80 with an average flatness coefficient R when no surfactant and nitrogen-containing compound are added to the precursor solution, or when surfactant or nitrogen-containing compound is added alone. avg A photoactive crystal material layer with a light absorption property of ≤75 cannot achieve the desired light absorption property improvement.

[0172] This application unexpectedly discovered that by simultaneously using a surfactant and a nitrogen-containing compound in the precursor solution, it is possible to successfully obtain a permeable grain 313 ratio p≥80 and an average flatness coefficient R. avg ≤75 photoactive crystal material layer.

[0173] It is important to emphasize that the surfactant and nitrogen-containing compound synergistically improved the photoelectric conversion performance of the photoactive crystal material layer. The last column of Table 1 uses the light conversion efficiency of Comparative Example 1 as a blank baseline to calculate the improvement rate of light conversion efficiency of other comparative examples and Examples 1-4 compared to Comparative Example 1. It can be observed that: The PCE improvement rate of Example 1 (26%) was significantly higher than the sum of the improvement rates of Comparative Examples 4 and 6 (18% + 3% = 21%). The PCE improvement rate of Example 2 (28%) is significantly higher than the sum of the improvement rates of Comparative Examples 2 and 5 (3% + 2% = 5%). The PCE improvement rate of Example 3 (31%) was significantly higher than the sum of the improvement rates of Comparative Examples 3 and 7 (7% + 8% = 15%). The PCE improvement rate of Example 4 (32%) is significantly higher than the sum of the improvement rates of Comparative Examples 4 and 8 (18+12%=30%). Due to an unexpected synergistic effect between the surfactant and the nitrogen-containing compound, the light absorption properties of the photoactive crystal material layer were significantly improved. Specifically, the proportion of 313 transverse grains in the active crystal material layer was p≥80, and the average flatness coefficient R was also improved. avg With a value of ≤75, photovoltaic devices with significantly improved energy conversion efficiency were obtained.

[0174] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A photovoltaic device, wherein, Includes a photoactive crystal material layer (103), wherein the photoactive crystal material layer (103) includes a first region; In the first region, the photoactive crystal material layer (103) includes through grains (313), which are grains that penetrate the photoactive crystal material layer (103), and the number of through grains (313) accounts for a percentage p ≥ 80% of the total number of grains in the photoactive crystal material layer (103); and In the first region, the photoactive crystal material layer (103) includes a backlight side (113) and backlight grains (31, 32, 33), wherein the backlight grains (31, 32, 33) are grains with at least one side exposed to the backlight side (113), and the side of the backlight grains (31, 32, 33) exposed to the backlight side (113) is a backlight crystal surface; The backlight side (113) has an average flatness coefficient R. avg R avg ≤75; Among them, the R of the backlight side (113) avg Calculated using the following formula: ； Among them, R i R is the flatness coefficient of the i-th backlight chip (31,32,33) in the first region. i Calculated using the following formula: R i =d i / h i Where, d i The width of the backlight crystal plane of the i-th backlight crystal (31,32,33) in the first region; Among them, h i The convex height of the backlight crystal surface of the i-th backlight crystal (31,32,33) in the first region; Where n is the total number of all backlight chips (31, 32, 33) in the first region. Wherein, the size of the first region in at least one direction along the surface of the photoactive crystal material layer (103) is 3 μm or more, or the size of the first region in at least two mutually perpendicular directions is 3 × 3 μm or more, or the area of ​​the first region is 10% or more of the area of ​​the backlight side or the light-receiving side of the photoactive crystal material layer (103), or the total number of grains in the first region of the photoactive crystal material layer (103) is 9 or more.

2. The photovoltaic device according to claim 1, wherein, The photoactive crystal material includes an A / M / X crystal material, which has the following general formula: [A] a [M] b [X] c [M] includes one or more first cations, wherein the first cation includes metal ions, quasi-metal ions, or combinations thereof; [A] includes one or more second cations; [X] includes one or more halide anions; a ranges from 1 to 6; b ranges from 1 to 6; c ranges from 1 to 18.

3. The photovoltaic device according to claim 2, wherein, a is 1, 2, 3, 4, 5, or 6; And / or, b is 1, 2, 3, 4, 5 or 6; And / or, c is 3, 6, 9, or 18.

4. The photovoltaic device according to claim 2, having one or more of the following features: (1) The one or more first cations are selected from Ca 2+ 、Sr 2+ Cd 2+ Cu 2+ Ni 2+ Mn 2+、 Fe 2+ Co 2+ Pd 2+ 、Ge 2 + Sn 2+、 Pb 2+ Yb 2+ Eu 2+ Bi3+, Sb3+, Pd 4+ W 4+ Re 4+ Os 4+ Ir 4+ Pt 4+ Sn 4+ Pb 4+ 、Ge 4+ Or Te 4+ ; (2) The one or more second cations are selected from Cs + 、(NR 1 R 2 R 3 R 4 ) + 、(R 1 R 2 N=CR 3 R 4 ) + 、(R 1 R 2 NC(R 5 )=NR 3 R 4 ) + or (R) 1 R 2 NC(NR 5 R 6 )=R 3 R 4 ) + ,in, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 Each is independently selected from H, substituted or unsubstituted C. 1-20 Alkyl or substituted or unsubstituted aryl; (3) The halogen anion is selected from Cl. - ,Br - or I - .

5. The photovoltaic device according to claim 4, wherein: The one or more first cations are selected from Cu 2+ Pb 2+ 、Ge 2+ or Sn 2+ ; and / or The one or more second cations are selected from Cs. + (CH3NH3) + (H2N-C(H)=NH2) + .

6. The photovoltaic device according to claim 2, wherein, The A / M / X crystal material includes FAPbF3 and FAPbBr. x I 3-x ,FAPbBr x Cl 3-x ,FAPbI x Br 3-x ,FAPbI x Cl 3-x ,FAPbCl x Br 3-x ,FAPbI 3-x Cl x CsPbF3, CsPbBr x I 3-x CsPbBr x Cl 3-x CsPbI x Br 3-x CsPbI x Cl 3-x CsPbCl x Br 3-x CsPbI 3-x Cl x FA 1-y Cs y PbI3, FA 1- y Cs y PbBr3, FA 1-y Cs y PbCl3, FA 1-y Cs y PbF3, FA 1-y Cs y PbBr x I 3-x FA 1-y Cs y PbBr x Cl 3-x FA 1- y Cs y PbI x Br 3-x FA 1-y Cs y PbI x Cl 3-x FA 1-y Cs y PbCl x Br 3-x FA 1-y Cs y PbI 3-x Cl x or a combination thereof; Where x = 0 - 3, y = 0.01 - 0.

25.

7. The photovoltaic device according to claim 2, wherein, The A / M / X crystal materials include FAPbI3, FAPbBr3, FAPbCl3, CsPbI3, CsPbBr3, CsPbCl3, or combinations thereof.

8. The photovoltaic device according to claim 2, wherein, The thickness of the photoactive crystal material layer is 100 nm or more.

9. The photovoltaic device according to claim 8, wherein, The thickness of the photoactive crystal material layer is 100-1000 nm.

10. The photovoltaic device according to claim 9, wherein, The thickness of the photoactive crystal material layer is 300-700 nm.

11. The photovoltaic device according to claim 1, wherein, It also includes a first charge transport layer (104) and a second charge transport layer (102), wherein the photoactive crystal material layer (103) is located between the first charge transport layer (104) and the second charge transport layer (102); The first charge transport layer (104) and the second charge transport layer (102) are respectively an electron transport layer and a hole transport layer, or The first charge transport layer (104) and the second charge transport layer (102) are the hole transport layer and the electron transport layer, respectively.

12. The photovoltaic device according to claim 11, wherein, It also includes a first electrode (105) and a second electrode (101), wherein the electron transport layer, the hole transport layer and the photoactive crystal material layer are located between the first electrode (105) and the second electrode (101).

13. The photovoltaic device according to claim 12, wherein, The first electrode (105) comprises a transparent conductive oxide; and / or The second electrode (101) comprises metal.

14. The photovoltaic device according to claim 1, wherein, The percentage of the number of through-grains (313) relative to the total number of grains in the photoactive crystal material layer (103) is p≥90%; and / or The average flatness coefficient R avg Satisfying 10≤R avg ≤70.

15. The photovoltaic device according to any one of claims 1-14, wherein, The average flatness coefficient R avg Satisfying 11.4≤R avg ≤59.

16. The photovoltaic device according to claim 1, wherein, The photovoltaic device is fabricated by the following method: The method includes setting a precursor composition on a matrix, the precursor composition comprising the following components: (a) At least one precursor compound; (b) Solvent; (c) Surfactants; and (d) Amino compounds.

17. The photovoltaic device according to claim 16, wherein, The method includes one or more of the following: (1) The surfactants include amphoteric surfactants; (2) The amino compounds include: nitrile amine compounds, amino acid compounds, hydrazine compounds, urea compounds, guanidine compounds, or their salts or hydrates.

18. The photovoltaic device according to claim 16, wherein, The surfactants include dodecylaminopropionate, dodecylethoxysulfobetaine, dodecyldimethylhydroxypropylsulfobetaine, zwitterionic polyacrylamide, octadecyldihydroxyethylamine oxide, tetradecyldihydroxyethylamine oxide, lauramidepropylamine oxide, dodecyl betaine, L-α-phosphocholine, 3-(N,N-dimethyltetradecylammonium)propanesulfonate, dodecylbenzenesulfonate, or combinations thereof.

19. The photovoltaic device according to claim 17, wherein, The amino compounds include: urea-formaldehyde, urea, biuret, triuret, isobutylidene diurea, hydrazine, guanidine, nitrile amine, aminosulfonic acid, or combinations thereof.

20. The photovoltaic device according to claim 17, wherein, The amino acid compounds include aminosulfonic acid compounds.

21. The photovoltaic device according to claim 16, wherein the precursor composition comprises a first solvent and a second solvent, the first solvent having a boiling point of 40-165°C; and the second solvent having a boiling point of 170-250°C.

22. The photovoltaic device according to claim 21, comprising one or more of the following: (1) The first solvent is selected from one or more of N,N-dimethylformamide, 2-methoxyethanol, and acetonitrile; (2) The second solvent is selected from one or more of dimethyl sulfoxide, N-methylpyrrolidone, and diphenyl sulfoxide; (3) The volume ratio of the first solvent to the second solvent is (4-10):

1.

23. The photovoltaic device of claim 16, wherein the precursor composition comprises: A first precursor compound, the first precursor compound containing a first cation; as well as The second precursor compound contains a second cation.

24. The photovoltaic device according to claim 23, comprising one or more of the following; (1) The first precursor compound contains a halide anion; (2) The second precursor compound contains a halide anion.

25. The photovoltaic device according to claim 23, comprising one or more of the following; (1) The first precursor compound includes lead iodide, lead bromide, or a combination thereof; (2) The second precursor compound includes formamidine hydroiodide, formamidine hydrobromide, cesium iodide, cesium bromide or a combination thereof.

26. The photovoltaic device of claim 16 further includes a step of curing the precursor composition disposed on the substrate surface.

27. The photovoltaic device according to claim 26, wherein the curing process comprises: Vacuum treatment, air knife treatment, infrared light treatment, or a combination thereof.

28. The photovoltaic device according to claim 16, further comprising annealing the cured product.

29. The photovoltaic device according to claim 28, wherein the annealing temperature is 100°C-170°C; and / or The annealing process takes 5-60 minutes.

30. The photovoltaic device according to claim 1, wherein, The photovoltaic device is fabricated by the following method: The photovoltaic device includes a first electrode (105) and a second electrode (101), a first charge transport layer (104) and a second charge transport layer (102) located between the first electrode (105) and the second electrode (101), and an A / M / X crystal material layer located between the first charge transport layer (104) and the second charge transport layer (102). The method includes: A first electrode (105) having a first charge transport layer (104) disposed on its surface is provided; According to the method for preparing A / M / X crystal materials, the A / M / X crystal material layer is formed on the surface of the first charge transport layer (104); A second charge transport layer (102) is formed on the A / M / X crystal material layer. A second electrode (101) is formed on the second charge transport layer (102); Wherein, the first charge transport layer (104) and the second charge transport layer (102) are respectively an electron transport layer and a hole transport layer, or The first charge transport layer (104) and the second charge transport layer (102) are the hole transport layer and the electron transport layer, respectively. Wherein, the size of the first region in at least one direction along the surface of the photoactive crystal material layer (103) is 3 μm or more, or the size of the first region in at least two mutually perpendicular directions is 3 × 3 μm or more, or the area of ​​the first region is 10% or more of the area of ​​the backlight side or the light-receiving side of the photoactive crystal material layer (103), or the total number of grains in the first region of the photoactive crystal material layer (103) is 9 or more.

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