Perovskite solar cell and preparation method thereof

Abstract

The invention relates to the technical field of perovskite solar cells, in particular to a perovskite solar cell and a preparation method thereof. The method comprises the following steps: placing a substrate deposited with a hole transport layer in polystyrene sphere dispersion liquid, and preparing a PbI2 layer on the hole transport layer covered with a layer of polystyrene spheres; sintering the substrate on which the PbI2 layer is prepared to obtain a substrate with a lead iodide layer of a porous structure; preparing a layer of iodide on the lead iodide layer with the porous structure, performing annealing treatment, and forming a perovskite layer through reaction of the iodide and lead iodide; and sequentially depositing an electron transport layer and a metal electrode layer on the perovskite layer to obtain the perovskite solar cell. By preparing the lead iodide layer with the porous structure, iodide and lead iodide at the bottom layer are promoted to be fully mixed to form perovskite, so that the problem that a device is unstable due to the fact that the lead iodide at the bottom layer cannot react completely is solved.

Description

Technical Field

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

[0002] As an emerging technology, perovskite solar cells are gradually gaining favor in the market due to their high efficiency. As the market demand for low-cost photovoltaic technology becomes increasingly urgent, perovskite solar cells are expected to become an important force in the future photovoltaic industry and make positive contributions to the optimization of the global energy structure and sustainable development.

[0003] One of the major issues currently hindering the commercial application of perovskite solar cells is light stability. This problem is mainly caused by the two-step method for preparing perovskite. When the upper organic layer is deposited on the lower dense lead iodide layer to react and generate the perovskite layer, the bottom dense lead iodide layer cannot react completely, resulting in the presence of some lead iodide in the bottom layer. Lead iodide is a photosensitive material that decomposes to produce lead and iodine under light conditions, destroying the lower interface and forming a large number of recombination centers, causing the device performance to deteriorate. At the same time, the decomposition of lead iodide will accelerate the decomposition of the upper perovskite layer, leading to the failure of the perovskite device. Therefore, reducing or even eliminating the residual lead iodide in the bottom layer is an effective way to effectively improve the stability of perovskite photovoltaic modules. Summary of the invention

[0004] The purpose of the present invention is to provide a perovskite solar cell and a preparation method thereof, by preparing a porous structure lead iodide layer to promote the full mixing of iodide and the underlying lead iodide to form perovskite, thereby solving the problem of device instability caused by the inability of the underlying lead iodide to fully react.

[0005] To achieve the above object, the present invention provides a method for preparing a perovskite solar cell, the method comprising:

[0006] placing a substrate on which a hole transport layer is deposited in a polystyrene sphere dispersion and preparing a PbI2 layer on the hole transport layer covered with a layer of polystyrene spheres;

[0007] Sintering the substrate after preparing the PbI2 layer to obtain a substrate with a lead iodide layer having a porous structure;

[0008] A layer of iodide is prepared on the porous structure lead iodide layer and annealed, so that a perovskite layer is formed by the reaction of the iodide and the lead iodide;

[0009] A perovskite solar cell is obtained by sequentially depositing an electron transport layer and a metal electrode layer on the perovskite layer.

[0010] The present invention also provides a perovskite solar cell prepared based on the perovskite solar cell preparation method, wherein the perovskite solar cell comprises a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, and a metal electrode layer arranged in layers in sequence.

[0011] Technical effects and advantages of the present invention:

[0012] The present invention prepares a porous structure lead iodide layer to promote the full mixing of iodide and the underlying lead iodide to form perovskite, thereby solving the problem of device instability caused by the inability of the underlying lead iodide to react completely.

[0013] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 Schematic diagram of the process for preparing perovskite solar cells;

[0016] Figure 2 The UV aging efficiency attenuation curves of the perovskite solar cells of the embodiment and the comparative example are shown;

[0017] Figure 3 It is a graph showing the double 85 aging efficiency attenuation curve of the perovskite solar cell of the embodiment and the comparative example. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0020] The present invention discloses a method for preparing a perovskite solar cell. Figure 1 As shown (taking the pin structure as an example), the method includes:

[0021] 1. Prepare a hole transport layer on a conductive substrate. For example, a hole transport layer, such as a NiOx layer, is prepared on a FTO conductive substrate by a slit coating method. Figure 1 (a) shown.

[0022] 2. Place the substrate with the hole transport layer deposited vertically in a polystyrene ball dispersion (the size of the polystyrene ball is 20-50 nm) for 1-5 minutes, then slowly remove the substrate from the polystyrene ball dispersion and dry it, so that a layer of polystyrene balls is covered on the hole transport layer of the substrate. Figure 1 (b) as shown.

[0023] The mass concentration of the polystyrene ball dispersion is 0.5wt%-2wt%.

[0024] 3. Prepare a PbI2 layer on the polystyrene spheres. For example, a PbI2 layer is prepared on the polystyrene spheres by a slit coating method. Then, the substrate is placed at a temperature of 200-400°C (preferably 300°C) for sintering for ≥30 minutes (preferably 40 minutes), the polystyrene spheres are removed, and a porous structure of lead iodide layer is formed, such as Figure 1 As shown in (c) and (d).

[0025] 4. Prepare a layer of iodide (preferably XI, but may be iodide of other formulations) on the porous lead iodide, and anneal at 100°C-150°C to allow the iodide to react with the underlying lead iodide to form a perovskite layer, such as Figure 1 (e) as shown.

[0026] 5. Sequentially prepare an electron transport layer and an electrode layer on the perovskite layer, such as by using physical vapor deposition to prepare the electron transport layer and the electrode layer, thereby completing the device assembly.

[0027] In order to better explain the present scheme, examples and comparative examples are provided below.

[0028] Example

[0029] The method for preparing a perovskite solar cell specifically comprises the following steps:

[0030] 1. After completing P1 cutting of the FTO substrate with laser, ultrasonic cleaning is performed with detergent, deionized water, acetone, and isopropanol in sequence, and then dried with nitrogen, and then treated with a UV ozone cleaning machine for 20 minutes.

[0031] 2. Preparation of hole transport layer. In this example, NiOx was used as the hole transport layer. First, NiOx nanoparticles were dispersed in deionized water (20 mg / mL), and the NiOx nanoparticle dispersion was obtained after ultrasonication for 2 h in an ultrasonicator. Then, the NiOx nanoparticle solution was spin-coated on the FTO glass by a coating method, and then annealed in air at 120°C for 30 min to obtain the hole transport layer.

[0032] 3. Preparation of a single layer of polystyrene spheres: First, a 2.5 wt% aqueous dispersion of polystyrene spheres (PS) with a size of 50 nm was diluted to a 0.5 wt% dilute solution, and then the substrate with the hole transport layer deposited was vertically immersed in the dilute solution and maintained for 1 minute, and then the substrate was slowly taken out at a speed of 0.1 cm / min and dried, thereby covering the hole transport layer of the substrate with a layer of polystyrene spheres.

[0033] 4. Porous Pb(I 0.83 Br 0.17 )2 layers are prepared. According to the perovskite components we need, such as Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3, a certain proportion of PbI2 and PbBr2 were dissolved in a mixed solvent of DFM and DMSO, the volume ratio of the mixed solvent was 4:1, and the solution concentration was 1.2 mol / L. Then the solution was prepared on a polystyrene ball by coating, and sintered at 300 degrees Celsius for 30 minutes, and the polystyrene ball was removed to form a porous Pb(I 0.83 Br 0.17 )2 layers, and obtain FTO / NiOx / PS / porous Pb(I 0.83 Br 0.17 )2 structure.

[0034] 5. Preparation of perovskite layer. A layer of organic iodide XI is prepared on the porous PbI2 layer. In this embodiment, Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3 is taken as the final perovskite component as an example. According to the element ratio required for this ratio, a certain proportion of CsI, FAI, and MAI are dissolved in isopropanol at a concentration of 1 mol / L. Then, the precursor solution is coated on the FTO / NiOx / PS / porous Pb(I 0.83 Br 0.17 )2 layer. Subsequently, the sample coated with the perovskite active layer was heat treated on a heating table at 150°C for 30 min to obtain Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3 floors.

[0035] 6. Preparation of electron transport layer: Fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was deposited on the perovskite layer by thermal evaporation.

[0036] 7. Use laser to perform P2 cutting on the film layer.

[0037] 8. Thermal evaporation metal electrode layer. Use thermal evaporation coating machine at 1.0×10 -4 Under a vacuum of 1.5 Pa, 200 nm of silver was thermally evaporated onto the hole transport layer to form a metal electrode layer.

[0038] 9. Use laser to perform P3 cutting on the film layer.

[0039] 10. The double-glass packaging process is used to package the components to obtain perovskite solar cells.

[0040] Comparative Example:

[0041] The method for preparing a perovskite solar cell specifically comprises the following steps:

[0042] 1. After completing P1 cutting of the FTO substrate with laser, ultrasonic cleaning is performed using a cleaning agent, deionized water, acetone, and isopropanol. After drying with nitrogen, it is then treated with an ultraviolet ozone cleaning machine for 20 minutes.

[0043] 2. Preparation of hole transport layer. In this example, NiOx was used as the hole transport layer. First, NiOx nanoparticles were dispersed in deionized water (20 mg / mL), and the NiOx nanoparticle dispersion was obtained after ultrasonication for 2 h in an ultrasonicator. Then, the NiOx nanoparticle solution was spin-coated on the FTO glass by a coating method, and then annealed in air at 120°C for 30 min to obtain the FTO / NiOx hole transport layer.

[0044] 3. Planar Pb(I 0.83 Br 0.17 )2 layers. According to the perovskite components we need, namely Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3, a certain proportion of PbI2 and PbBr2 were dissolved in a mixed solvent of DFM and DMSO, the volume ratio of the mixed solvent was 4:1, and the solution concentration was 1.2 mol / L. Then the solution was prepared on the FTO / NiOx / PS substrate by coating, and annealed at 300 degrees Celsius to obtain FTO / NiOx / PS / Pb(I 0.83 Br 0.17 )2 structure.

[0045] 4. Preparation of perovskite layer. A layer of organic iodide XI is prepared on the porous PbI2 layer. In this embodiment, Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3 is taken as the final perovskite component as an example. According to the element ratio required for this ratio, a certain proportion of CsI, FAI, and MAI are dissolved in isopropanol at a concentration of 1 mol / L. Then the precursor solution is applied on the

[0046] FTO / NiOx / PS / Pb(I 0.83 Br 0.17 )2 layer. Subsequently, the sample coated with the perovskite active layer was heat treated on a heating table at 150°C for 10 min to obtain Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3 floors.

[0047] 5. Preparation of electron transport layer: Fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was deposited on the perovskite layer by thermal evaporation.

[0048] 6. Use laser to perform P2 cutting on the film layer.

[0049] 7. Thermal evaporation metal electrode layer. Use thermal evaporation coating machine at 1.0×10 -4 Under a vacuum of 1.5 Pa, 200 nm of silver was thermally evaporated onto the hole transport layer to form a metal electrode layer.

[0050] 8. Use laser to perform P3 cutting on the film layer.

[0051] 9. The double-glass packaging process is used to package the components to obtain perovskite solar cells.

[0052] In order to verify that this solution can solve the above technical problems, that is, improve the stability of perovskite solar cells, the perovskite solar cells obtained in the embodiment and the comparative example are placed in a UV aging box and a double 85 aging box for aging tests. The aging results are shown in FIG. Figure 2-3 shown.

[0053] from Figure 2-3 It can be seen that the stability of the perovskite solar cell prepared by the method of the embodiment has been greatly improved. For example, after UV aging for 100kwh, the efficiency of the embodiment still maintains 86% of the initial efficiency, while the efficiency of the comparative example is only 68% of the initial efficiency. At the same time, after aging for 1000 hours in a double 85 aging box, the efficiency of the embodiment still maintains 91% of the initial efficiency, while the efficiency of the comparative example is only 82% of the initial efficiency.

[0054] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that: The method comprises: placing a substrate on which a hole transport layer is deposited in a polystyrene sphere dispersion and preparing a PbI2 layer on the hole transport layer covered with a layer of polystyrene spheres; Sintering the substrate after preparing the PbI2 layer to obtain a substrate with a lead iodide layer having a porous structure; A layer of iodide is prepared on the porous structure lead iodide layer and annealed, so that a perovskite layer is formed by the reaction of the iodide and the lead iodide; A perovskite solar cell is obtained by sequentially depositing an electron transport layer and a metal electrode layer on the perovskite layer.

2. The method for preparing a perovskite solar cell according to claim 1, characterized in that: Obtaining a substrate having a hole transport layer deposited thereon, comprising: Cleaning the conductive substrate; A hole transport layer is prepared on the cleaned conductive substrate.

3. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The size of the polystyrene spheres is 20-50 nm.

4. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The sintering conditions include: temperature of 200-400°C and time ≧30 min.

5. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The annealing temperature is 100-150°C and the time is 15-30 minutes.

6. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The mass concentration of the polystyrene ball dispersion is 0.5wt%-2wt%.

7. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The PbI2 layer was prepared on a hole transport layer covered with a layer of polystyrene spheres by slot coating.

8. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The substrate with the hole transport layer deposited thereon is placed vertically in the polystyrene ball dispersion and immersed for 1-5 minutes.

9. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The material of the metal electrode layer includes one of the following: Au, Ag, Cu and Al.

10. A perovskite solar cell prepared according to the method for preparing a perovskite solar cell according to any one of claims 1 to 9, characterized in that: The perovskite solar cell comprises a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, and a metal electrode layer which are arranged in layers in sequence.

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