Perovskite precursor solution and use thereof

Abstract

The application provides a perovskite precursor solution and application thereof, and the perovskite precursor solution comprises a perovskite precursor main body solution and an organic salt additive; the organic salt additive comprises a compound with a structural formula of ABX, wherein A is selected from a substituted or unsubstituted saturated nitrogen heterocycle, B is selected from a formamidinium group, X is selected from hydrogen chloride, hydrogen iodide or hydrogen bromide, and a nitrogen atom in A and a carbon atom in B are covalently connected to form a guanidino group structure; the number of carbon atoms in the ring of the saturated nitrogen heterocycle is 2-10, and the number of nitrogen atoms in the ring is 1-5. The perovskite precursor solution can optimize the orientation direction of crystal growth to improve the carrier transport capacity, and can effectively passivate the grain boundary defects, so as to improve the photoelectric conversion efficiency.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell fabrication technology, and particularly relates to a perovskite precursor solution and its application. Background Technology

[0002] Perovskite solar cells, as a representative of third-generation photovoltaic technology, have become a research hotspot in the photovoltaic field due to their advantages such as high photoelectric conversion efficiency, tunable bandgap, and low manufacturing cost.

[0003] However, the perovskite light-absorbing layer, as the core component of perovskite solar cells, is susceptible to the effects of temperature, humidity, and light, causing degradation during photoelectric conversion and resulting in poor device stability. This is because defects on the perovskite surface allow oxygen and water molecules to enter the perovskite light-absorbing layer, damaging its original structure. At the same time, charge recombination centers formed by defects cause nonradiative recombination, hindering charge transport and leading to a decrease in the device's photoelectric conversion efficiency. Summary of the Invention

[0004] This invention provides a perovskite precursor solution and its application. The perovskite precursor solution can optimize the orientation of crystal growth to improve carrier transport capability and can also effectively passivate grain boundary defects, thereby improving photoelectric conversion efficiency.

[0005] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows: The first aspect of the present invention provides a perovskite precursor solution, comprising a perovskite precursor bulk solution and an organic salt additive; The organic salt additive includes a compound with the structural formula ABX, wherein A is selected from substituted or unsubstituted saturated nitrogen heterocycles, B is selected from formamidinium groups, and X is selected from hydrogen chloride, hydrogen iodide, or hydrogen bromide, and the nitrogen atom in A is covalently connected to the carbon atom in B to form a guanidine structure. The saturated nitrogen heterocycle has 2 to 10 carbon atoms and 1 to 5 nitrogen atoms.

[0006] As can be seen from the above technical solution, the perovskite precursor solution provided in the first aspect of this invention has an organic salt additive in it that forms a guanidine structure by covalently linking the nitrogen atom in the saturated nitrogen heterocycle with the carbon atom of the formamidinium group. This guanidine structure can not only interact with ions in the perovskite precursor solution in multiple ways, inducing the perovskite crystal to form a two-dimensional structure and optimizing the crystal growth orientation to improve carrier transport capability, but also combine with uncoordinated ions at the perovskite grain boundaries to form stable coordination bonds, effectively passivating grain boundary defects and thus improving photoelectric conversion efficiency.

[0007] A second aspect of this invention provides a method for preparing a perovskite precursor solution, comprising the following steps: Organic salt additives were added to the perovskite precursor bulk solution and stirred evenly to obtain the perovskite precursor solution. The organic salt additive includes a compound with the structural formula ABX, wherein A is selected from substituted or unsubstituted saturated nitrogen heterocycles, B is selected from formamidinium groups, and X is selected from hydrogen chloride, hydrogen iodide, or hydrogen bromide. The nitrogen atom in A is covalently connected to the carbon atom in B to form a guanidine structure. The number of carbon atoms in the saturated nitrogen heterocycle is 2 to 10, and the number of nitrogen atoms in the ring is 1 to 5.

[0008] As can be seen from the above technical solutions, the method for preparing the perovskite precursor solution provided in the second aspect of this invention obtains the perovskite precursor solution by directly adding organic salt additives to the main perovskite precursor solution and stirring until homogeneous, without the need for additional post-processing or complex process steps. This preparation method has a simple process flow, low production cost, and broad practical application value.

[0009] A third aspect of the present invention provides a perovskite light-absorbing layer prepared from a perovskite precursor solution as described in any embodiment of the present invention.

[0010] As can be seen from the above technical solutions, the perovskite light-absorbing layer provided in the third aspect of the present invention can effectively passivate grain boundary defects and suppress nonradiative recombination of charge carriers.

[0011] A fourth aspect of the present invention provides a perovskite solar cell, comprising a substrate, a hole transport layer and a perovskite light-absorbing layer as described in the embodiments of the present invention, stacked sequentially.

[0012] As can be seen from the above technical solutions, the perovskite solar cell provided by the fourth aspect of the present invention has effectively improved open-circuit voltage, short-circuit current density, fill factor and photoelectric conversion efficiency, and the overall performance of the device is excellent. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 These are schematic diagrams of the perovskite solar cells provided in Examples 1-8 and Comparative Examples 1-5; Figure 2 These are voltage and current density curves provided in Example 1 and Comparative Example 1; Figure 3 This is a comparison diagram of the open-circuit voltage provided in Example 1 and Comparative Examples 1 to 5; Figure 4 This is a comparison diagram of the short-circuit current density provided in Example 1 and Comparative Examples 1 to 5; Figure 5 This is a comparison chart of the fill factor provided in Example 1 and Comparative Examples 1-5; Figure 6 This is a comparison chart of photoelectric conversion efficiency provided in Example 1 and Comparative Examples 1-5; Figure 7 These are the voltage and current density curves provided in Example 9 and Comparative Example 6; Explanation of reference numerals in the attached figures: 1. Glass substrate; 2. Transparent oxide electrode; 3. Hole transport layer; 4. Perovskite light-absorbing layer; 5. Electron transport layer; 6. Hole blocking layer; 7. Metal electrode. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] The flowchart shown in the attached diagram is for illustrative purposes only and does not necessarily include all content and operations / steps, nor does it necessarily have to be performed in the order described. For example, some operations / steps can be broken down, combined, or partially merged, so the actual execution order may change depending on the actual situation.

[0017] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0018] It should also be understood that the term “and / or” as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0019] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0020] As the core component of perovskite solar cells, the perovskite light-absorbing layer is susceptible to the effects of temperature, humidity, and light, which can cause degradation during photoelectric conversion and lead to poor device stability. This is because defects on the perovskite surface allow oxygen and water molecules to enter the perovskite light-absorbing layer and destroy its original structure. At the same time, the charge recombination centers formed by the defects cause nonradiative recombination, which hinders carrier transport and reduces the photoelectric conversion efficiency of the device.

[0021] In view of this, embodiments of the present invention provide a perovskite precursor solution, comprising a precursor solution and an organic salt additive; the organic salt additive comprises a compound with the structural formula ABX, wherein A is selected from a substituted or unsubstituted saturated nitrogen heterocycle, B is selected from a formamidinium group, and X is selected from hydrogen chloride, hydrogen iodide, or hydrogen bromide, wherein the nitrogen atom in A is covalently connected to the carbon atom in B to form a guanidine group structure; the number of carbon atoms in the saturated nitrogen heterocycle is 2 to 10, and the number of nitrogen atoms in the ring is 1 to 5.

[0022] In this embodiment of the invention, the organic salt additive forms a guanidine structure by covalently linking the nitrogen atom in the saturated nitrogen heterocycle with the carbon atom in the formamidinium group. This guanidine structure can not only interact with ions in the precursor solution in multiple ways, inducing the perovskite crystal to form a two-dimensional structure, optimizing the orientation of crystal growth and improving carrier transport capability, but also combine with uncoordinated ions at the perovskite grain boundaries to form stable coordination bonds, achieving effective passivation of grain boundary defects, thereby improving photoelectric conversion efficiency.

[0023] Specifically, 2~10 refers to the number of carbon atoms in the ring of a saturated nitrogen heterocycle being 2, 3, 4, 5, 6, 7, 8, 9 or 10, and 1~5 refers to the number of nitrogen atoms in the ring of a saturated nitrogen heterocycle being 1, 2, 3, 4 or 5.

[0024] In some embodiments, the substituents in A may be the same or different, and are each independently selected from alkyl groups having 1 to 5 carbon atoms.

[0025] Specifically, alkyl groups of 1 to 5 refer to those with 1, 2, 3, 4, or 5 carbon atoms.

[0026] In some embodiments, the ring of A also includes other heteroatoms selected from oxygen or sulfur.

[0027] For example, the nitrogen atom in the ring is located at position 1, and other heteroatoms are located at position 4.

[0028] In some embodiments, the structural formula of A is selected from: , , , , , , , , , ; R1 and R2 are each independently selected from alkyl groups having 1 to 5 carbon atoms.

[0029] Specifically, alkyl groups of 1 to 5 refer to those with 1, 2, 3, 4, or 5 carbon atoms.

[0030] In some embodiments, R1 and R2 are independently selected from methyl, ethyl, and propyl, respectively.

[0031] In some embodiments, the structural formula of the organic salt additive is selected from: , , , , , , , , , .

[0032] In some embodiments, the organic salt additive in the perovskite precursor solution has a mass concentration of 0.1 mg / mL to 3 mg / mL.

[0033] By controlling the concentration of organic salt additives between 0.1 mg / mL and 3 mg / mL, it is possible to induce the formation of a two-dimensional structure in perovskite crystals, optimize the orientation of crystal growth, and enhance carrier transport capability. Furthermore, it can combine with uncoordinated ions at perovskite grain boundaries to form stable coordination bonds, effectively passivating grain boundary defects. This effectively blocks moisture and oxygen from entering the perovskite light-absorbing layer, extending device lifetime and reducing non-radiative recombination, thus improving the device's photoelectric conversion efficiency. If the concentration of organic salt additives is less than 0.1 mg / mL, it may be insufficient to fully passivate grain boundary defects or effectively suppress carrier recombination, resulting in limited improvement in device photoelectric conversion efficiency. If the concentration of organic salt additives is greater than 3 mg / mL, aggregation or even precipitation may occur within the perovskite light-absorbing layer, damaging the film morphology and crystal quality, thereby causing a decrease in device photoelectric conversion efficiency. For example, the mass concentration of the organic salt additive can be any typical but non-limiting value such as 0.1 mg / mL, 0.3 mg / mL, 0.5 mg / mL, 0.8 mg / mL, 1 mg / mL, 1.2 mg / mL, 1.5 mg / mL, 1.7 mg / mL, 2 mg / mL, 2.5 mg / mL, 2.6 mg / mL, 3 mg / mL, or any range between any two values.

[0034] The method for preparing this perovskite precursor solution includes the following steps: Organic salt additives were added to the perovskite precursor bulk solution and stirred evenly to obtain the perovskite precursor solution. Organic salt additives include compounds with the structural formula ABX, wherein A is selected from substituted or unsubstituted saturated nitrogen heterocycles, B is selected from formamidinium groups, and X is selected from hydrogen chloride, hydrogen iodide, or hydrogen bromide. The nitrogen atom in A is covalently connected to the carbon atom in B to form a guanidine structure. The number of carbon atoms in the saturated nitrogen heterocycle is 2 to 10, and the number of nitrogen atoms in the ring is 1 to 5.

[0035] The preparation method of the perovskite precursor solution in this invention is simple and convenient. Organic salt additives are directly added to the main perovskite precursor solution and stirred until homogeneous. No additional post-treatment or complex process steps (e.g., multi-step surface modification or post-passivation processes) are required. This preparation method has a simple process flow, low production cost, and broad practical application value.

[0036] Embodiments of the present invention provide a perovskite light-absorbing layer prepared from a perovskite precursor solution according to any of the above embodiments. This perovskite light-absorbing layer also possesses the advantages of the aforementioned perovskite precursor solution, and will not be elaborated further here.

[0037] An embodiment of the present invention provides a perovskite solar cell, comprising a substrate, a hole transport layer and a perovskite light-absorbing layer of the above embodiment stacked sequentially.

[0038] Specifically, a complete perovskite solar cell comprises a substrate, a transparent oxide electrode, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, a hole blocking layer, and a metal electrode, stacked sequentially. The substrate and the transparent oxide electrode stacked on the substrate constitute the base material, which can be glass or a silicon wafer. The transparent oxide electrode is made of one or more of indium tin oxide (ITO), indium zinc oxide (IZO), or fluorine-doped tin oxide (FTO). Based on the advantages of the perovskite light-absorbing layer in the aforementioned perovskite precursor solution, this perovskite solar cell exhibits excellent photoelectric conversion efficiency.

[0039] The following detailed description, through specific embodiments and experimental data, illustrates the perovskite precursor solution and its applications provided by this invention, but should not be construed as limiting the invention. Any modifications or substitutions made to the methods, steps, or conditions of this invention without departing from its spirit and essence are within the scope of this invention.

[0040] Example 1 Please see Figure 1 The method for preparing perovskite precursor solution includes the following steps: Organic salt additives were added to the perovskite precursor bulk solution and stirred evenly to obtain the perovskite precursor solution. The main component of the perovskite precursor bulk solution is Cs. 0.05 FA 0.85 MA 0.1 PbI3, organic salt additives include compounds with the structural formula ABX, wherein A is selected from... B is selected from a formamidinium group, X is selected from hydrogen chloride, and the nitrogen atom in A is covalently linked to the carbon atom in B to form a guanidine group structure. Therefore, the structural formula of the organic salt additive is: In the perovskite precursor solution, the mass concentration of the organic salt additive is 1 mg / mL.

[0041] Example 2 The difference between this embodiment and Embodiment 1 is that A is selected from... The structural formula of the organic salt additive is .

[0042] Example 3 The difference between this embodiment and Embodiment 1 is that A is selected from... X is selected from hydrogen iodide, and the structural formula of the organic salt additive is: .

[0043] Example 4 The difference between this embodiment and Embodiment 1 is that A is selected from... The structural formula of the organic salt additive is .

[0044] Example 5 The difference between this embodiment and Embodiment 1 is that A is selected from... X is selected from hydrogen iodide, and the structural formula of the organic salt additive is: .

[0045] Example 6 The difference between this embodiment and Example 1 is that the mass concentration of the organic salt additive is 0.1 mg / mL.

[0046] Example 7 The difference between this embodiment and Example 1 is that the mass concentration of the organic salt additive is 2 mg / mL.

[0047] Example 8 The difference between this embodiment and Example 1 is that the mass concentration of the organic salt additive is 3 mg / mL.

[0048] Example 9 The difference between this embodiment and Example 1 is that the main component of the perovskite precursor bulk solution is Cs. 0.05 FA 0.8 MA 0.15 Pb(I 0.76 Br 0.243.

[0049] Comparative Example 1 The perovskite precursor bulk solution was stirred until homogeneous to obtain the perovskite precursor solution. The perovskite precursor bulk solution was Cs. 0.05 FA 0.85 MA 0.1 PbI3.

[0050] Comparative Example 2 Add the additive to the perovskite precursor bulk solution and stir until homogeneous to obtain the perovskite precursor solution. Among them, the perovskite precursor bulk solution is Cs 0.05 FA 0.85 MA 0.1 The structural formula of PbI3, the additive is as follows: In the perovskite precursor solution, the mass concentration of the additive is 1 mg / mL.

[0051] Comparative Example 3 The difference between this comparative example and Comparative Example 2 is that the structural formula of the additive is: .

[0052] Comparative Example 4 The difference between this comparative example and Comparative Example 2 is that the structural formula of the additive is: .

[0053] Comparative Example 5 The difference between this comparative example and Comparative Example 2 is that the structural formula of the additive is: .

[0054] Comparative Example 6 The difference between this comparative example and Comparative Example 1 is that the main component of the perovskite precursor bulk solution is Cs. 0.05 FA 0.8 MA 0.15 Pb(I 0.76 Br 0.24 3.

[0055] The perovskite light-absorbing layer and the solar cell including the perovskite light-absorbing layer were prepared using the perovskite precursor solution in the above embodiments and comparative examples.

[0056] The perovskite light-absorbing layers corresponding to Examples 1-8 and Comparative Examples 1-5 were prepared as follows: 60 μL of perovskite precursor solution was taken and spin-coated in two steps onto a surface with an area of ​​2.25 cm². 2On an ITO glass substrate with a hole transport layer, spin-coating parameters were applied at 1000 rpm for 5 s and 5000 rpm for 30 s. In the second spin-coating step, 150 μL of chlorobenzene anti-solvent was added dropwise at the 10th second before the end of the spin-coating process. After spin-coating, the film was annealed at 100 °C for 15 min to form a perovskite light-absorbing layer.

[0057] The perovskite light-absorbing layer corresponding to Example 9 and Comparative Example 6 was prepared as follows: 60 μL of perovskite precursor solution was spin-coated in two steps onto a surface area of ​​2.25 cm². 2 On an ITO glass substrate with a hole transport layer, spin-coating parameters were applied at 1000 rpm for 10 s and 6000 rpm for 30 s. In the second spin-coating step, 130 μL of chlorobenzene anti-solvent was added dropwise at the 10th s before the end of the spin-coating period. After spin-coating, the film was annealed at 100 °C for 20 min to form a perovskite light-absorbing layer.

[0058] Perovskite solar cells containing a perovskite light-absorbing layer were prepared using the perovskite solutions in the above embodiments and comparative examples, and the specific structures are as follows. Figure 2 As shown, it includes a glass substrate 1, a transparent oxide electrode 2, a hole transport layer 3, a perovskite light-absorbing layer 4, an electron transport layer 5, a hole blocking layer 6, and a metal electrode 7, which are stacked sequentially.

[0059] The fabrication method of perovskite solar cells includes the following steps: The ITO glass substrate was ultrasonically cleaned for 20 minutes each with deionized water, acetone and isopropanol, then dried and treated with ultraviolet ozone for 15 minutes. Spin-coat a 0.5 mg / mL 4PADCB ethanol solution onto a clean ITO glass substrate at 3000 rpm for 30 seconds. Place the ITO glass substrate with the 4PADCB ethanol solution spin-coated on a hot plate and heat it at 100°C for 10 minutes to form a hole transport layer. Prepare perovskite precursor solutions according to the examples or comparative examples; According to the preparation method of the perovskite light-absorbing layer in the embodiments or comparative examples, a perovskite light-absorbing layer is formed on the hole transport layer. When the vacuum degree is below 8×10 4 Under the condition of Pa, C is sequentially deposited by thermal evaporation. 60 BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and Cu form the electron transport layer, hole blocking layer, and metal electrode, respectively.

[0060] Test case The perovskite solar cells prepared using the perovskite precursor solutions of Examples 1-5 and Comparative Examples 1-5 of the present invention are narrow bandgap perovskite solar cells, and the perovskite solar cells prepared using the perovskite precursor solutions of Example 9 and Comparative Example 6 of the present invention are wide bandgap perovskite solar cells. The open-circuit voltage, short-circuit current density, fill factor and photoelectric conversion efficiency of the above perovskite solar cells were tested, and the test results are shown in Table 1.

[0061] Table 1

[0062] Through Table 1 and Figures 3-7 As can be seen, compared with Comparative Examples 1-5, the open-circuit voltage, short-circuit current density, fill factor and photoelectric conversion efficiency of Examples 1-5 of the present invention are significantly improved; compared with Comparative Example 6, the performance parameters of Example 9 of the present invention are also significantly improved. This shows that the organic salt additive of the present invention can optimize the orientation direction of crystal growth to improve the carrier transport capability, and can combine with uncoordinated ions at the perovskite grain boundary to form stable coordination bonds, thereby effectively passivating grain boundary defects and improving the performance of perovskite solar cell devices.

[0063] Based on the data from Examples 6-8, it can be seen that Example 1 of the present invention has the highest open-circuit voltage, short-circuit current density, fill factor, and photoelectric conversion efficiency. This indicates that the optimal mass concentration of the organic salt additive is 1 mg / mL. At this concentration, the passivation of defects and the enhancement of carrier transport can be fully utilized to achieve the best overall photovoltaic performance of the device.

[0064] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A perovskite precursor solution, characterized in that, Includes perovskite precursor bulk solution and organic salt additives; The organic salt additive includes a compound with the structural formula ABX, wherein A is selected from substituted or unsubstituted saturated nitrogen heterocycles, B is selected from formamidinium groups, and X is selected from hydrogen chloride, hydrogen iodide, or hydrogen bromide, and the nitrogen atom in A is covalently connected to the carbon atom in B to form a guanidine structure. The saturated nitrogen heterocycle has 2 to 10 carbon atoms and 1 to 5 nitrogen atoms.

2. The perovskite precursor solution according to claim 1, characterized in that, The substituents in A may be the same or different, and are independently selected from alkyl groups having 1 to 5 carbon atoms.

3. The perovskite precursor solution according to claim 1, characterized in that, The ring of A also includes other heteroatoms selected from oxygen or sulfur.

4. The perovskite precursor solution according to claim 1, characterized in that, The structural formula of A is selected from: , , , , , , , , ; R1 and R2 are each independently selected from alkyl groups having 1 to 5 carbon atoms.

5. The perovskite precursor solution according to claim 4, characterized in that, R1 and R2 are independently selected from methyl, ethyl, and propyl, respectively.

6. The perovskite precursor solution according to claim 1, characterized in that, The structural formula of the organic salt additive is selected from: , , , , , , , , , .

7. The perovskite precursor solution according to claim 1, characterized in that, In the perovskite precursor solution, the mass concentration of the organic salt additive is 0.1 mg / mL to 3 mg / mL.

8. A method for preparing a perovskite precursor solution, characterized in that, Includes the following steps: Organic salt additives were added to the perovskite precursor bulk solution and stirred evenly to obtain the perovskite precursor solution. The organic salt additive includes a compound with the structural formula ABX, wherein A is selected from substituted or unsubstituted saturated nitrogen heterocycles, B is selected from formamidinium groups, and X is selected from hydrogen chloride, hydrogen iodide, or hydrogen bromide. The nitrogen atom in A is covalently connected to the carbon atom in B to form a guanidine structure. The number of carbon atoms in the saturated nitrogen heterocycle is 2 to 10, and the number of nitrogen atoms in the ring is 1 to 5.

9. A perovskite light-absorbing layer, characterized in that, It is prepared from the perovskite precursor solution as described in any one of claims 1 to 7.

10. A perovskite solar cell, characterized in that, It includes a substrate, a hole transport layer, and a perovskite light-absorbing layer as described in claim 9, which are stacked sequentially.

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