Method for efficiently preparing perovskite layer-hole transport layer in one step

Abstract

The invention relates to a method for efficiently preparing a perovskite layer-hole transport layer in one step, which comprises the following specific steps: 1) preparing a perovskite precursor solution, then adding 1, 4-butane sultam and a hole transport material into the solution, and shaking until the materials are completely dissolved to obtain a mixed solution of perovskite and the hole transport material; and 2) coating the mixed solution of the perovskite and the hole transport material obtained in the step 1) on an ITO conductive substrate with a clean surface to obtain a precursor thin film, and annealing the obtained precursor thin film to obtain a composite thin film of a lower hole transport layer and an upper perovskite layer. According to the preparation method provided by the invention, the high-quality perovskite layer / hole layer heterojunction thin film can be obtained through one-step deposition, the conversion efficiency of the p-i-n perovskite solar cell is also improved to a certain extent, the preparation process is simplified, the production cost is reduced, and the preparation method has positive significance on large-scale preparation of the perovskite solar cell.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrical components, and particularly relates to a method for efficiently preparing a perovskite layer-hole transport layer in one step. Background Art

[0002] With the continuous growth of global demand for green energy, the scale of solar energy applications has expanded significantly. China's photovoltaic industry has maintained a strong development momentum, and the annual newly installed capacity has ranked first in the world for 11 consecutive years. According to the statistics of the National Energy Administration, the newly installed capacity of solar photovoltaic in China reached 216.88 GW in 2023, setting a record high.

[0003] Perovskite solar cells are a type of high-efficiency solar cells with great potential for commercial applications. Usually, in order to form a high-quality p-i-n or n-i-p heterojunction, three functional layers (hole transport layer, perovskite layer, electron transport layer) are sequentially deposited in three steps to ensure the denseness and uniformity of each layer of the thin film, so as to achieve good charge transport and reduce voltage loss. In order to improve production efficiency, a method of depositing without a transport layer and a method of co-depositing a transport layer (HTL / ETL) with a perovskite layer have been proposed. However, the quality of the perovskite heterojunction prepared by the existing methods is still inferior to that of the layer-by-layer deposition method, and the corresponding cell efficiency will be affected.

[0004] The present invention introduces 1,4-butanesultam into the mixed solution of the perovskite precursor and the hole transport material, and deposits the perovskite layer and the hole transport layer in one step, and the obtained perovskite heterojunction has good quality. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for efficiently preparing a perovskite layer-hole transport layer in one step, which can simultaneously form a dense perovskite layer and a hole transport layer by one-step deposition, effectively reduce the preparation cost and improve the production efficiency.

[0006] The present invention provides a method for efficiently preparing a perovskite layer-hole transport layer in one step, and the specific steps are as follows:

[0007] 1) Prepare a perovskite precursor solution, then add 1,4-butanesultam and a hole transport material to the solution, and shake until completely dissolved to obtain a mixed solution of perovskite and the hole transport material;

[0008] 2) Coat the mixed solution of perovskite and the hole transport material obtained in step 1) on a clean ITO conductive substrate to obtain a precursor thin film, and then anneal the obtained precursor thin film to obtain a composite thin film of a lower hole transport layer and an upper perovskite layer (perovskite layer / hole transport layer heterojunction).

[0009] According to the above scheme, the preparation method of the perovskite precursor solution in step 1) is as follows: Weigh the corresponding FAPbI 3 , MA x FA 1-x Pb(I y Br 1-y ) 3 or Cs x FA 1-x Pb(I y Br 1-y ) 3 raw materials, add methylammonium chloride (MACl) accounting for 5-40% of the molar amount of PbI 2 in the raw materials, dissolve them in a solvent to obtain a perovskite precursor solution, and the concentration of the perovskite precursor solution is 1-2M.

[0010] According to the above scheme, the solvent is a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) in a volume ratio of 4-7:1, or a mixed solvent of 2-methoxyethanol (2-ME) and 1,3-dimethyl-2-imidazolidinone (DMI) in a volume ratio of 4-7:1.

[0011] According to the above scheme, the hole transporting material in step 1) is one of (2-(9H-carbazol-9-yl)ethyl)phosphonic acid, [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethyl-9H-carbazol-9-yl)ethyl]phosphonic acid, and [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphoric acid.

[0012] According to the above scheme, the concentration of 1,4-butanesultone in the mixed solution of perovskite and hole transporting material in step 1) is 0.05-0.2M (mol / L), and the concentration of the hole transporting material is 0.001-0.01M.

[0013] According to the above scheme, the method of coating the mixed solution of perovskite and hole transporting material on the surface-clean ITO conductive substrate in step 2) is one of spin coating, blade coating, or slot coating. When the spin coating method is selected, the spin coating speed is 4000-5000 revolutions per minute, and the spin coating time is 40-50 seconds.

[0014] According to the above scheme, the process conditions of the annealing treatment in step 2) are: the annealing temperature is 120-130°C, and the annealing time is 20-40 minutes.

[0015] The present invention also includes the application of the above method for efficiently preparing a perovskite layer-hole transporting layer in the preparation of perovskite solar cells.

[0016] The present invention also includes a perovskite layer - hole transport layer prepared by the above method, wherein the perovskite layer has a band gap of 1.55 - 1.77 eV, the thickness of the perovskite layer is 500 - 900 nm, and the thickness of the hole layer is 1 - 3 nm.

[0017] Furthermore, the present invention also includes a perovskite solar cell containing the above perovskite layer - hole transport layer, which includes an ITO conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, a buffer layer, and a top electrode laminated in sequence from bottom to top.

[0018] The present invention also includes a preparation method of the above perovskite solar cell, and the specific steps are as follows:

[0019] 1) Prepare a perovskite precursor solution, then add 1,4 - butanesultone and a hole transport material to the solution, and shake until completely dissolved to obtain a mixed solution of perovskite and the hole transport material;

[0020] 2) Coat the mixed solution of perovskite and the hole transport material obtained in step 1) on a clean ITO conductive substrate surface to obtain a precursor film, and then anneal the obtained precursor film to obtain a composite film of a lower - layer hole transport layer and an upper - layer perovskite layer;

[0021] 3) Deposit an electron transport layer, a buffer layer, and a top electrode in sequence on the surface of the composite film of the lower - layer hole transport layer and the upper - layer perovskite layer obtained in step 2) to obtain a perovskite solar cell (p - i - n type).

[0022] According to the above scheme, the electron transport layer in step 3) is C 60 or tin oxide, with a thickness of 20 - 30 nm, the buffer layer is bathocuproine, with a thickness of 10 - 20 nm, and the top electrode is silver or copper, with a thickness of 80 - 100 nm.

[0023] In the process of preparing the perovskite layer - hole transport layer of the present invention, it is found that adding an appropriate amount of 1,4 - butanesultone to the system and then annealing can enable the hole transport material to be uniformly and densely deposited at the bottom of the film, and a dense perovskite layer is formed at the top of the film, so as to deposit the two - layer functional materials of the perovskite layer - hole transport layer in one step.

[0024] The beneficial effects of the present invention are as follows: The preparation method provided by the present invention can achieve depositing a high - quality perovskite layer / hole layer heterojunction film in one step, and the conversion efficiency of the p - i - n perovskite solar cell is also improved to a certain extent. It simplifies the preparation process, reduces the production cost, and has a positive significance for the large - scale preparation of perovskite solar cells. Description of the Drawings

[0025] Figure 1Flow chart for preparing the perovskite layer / hole transport layer heterojunction in Example 1 and Comparative Example 1 of the present invention;

[0026] Figure 2 Cross-sectional and lower interface scanning electron microscope images of the perovskite layer / hole transport layer heterojunctions prepared in Example 1 and Comparative Example 1;

[0027] Figure 3 SEM image of the surface of the hole transport layer obtained in step 4) of Comparative Example 2;

[0028] Figure 4 J-V curves of the p-i-n perovskite solar cells obtained in Example 1, Example 2, Comparative Example 1 and Comparative Example 2. Detailed implementation manners

[0029] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to examples and the accompanying drawings.

[0030] Example 1

[0031] A method for efficiently preparing a perovskite layer-hole transport layer in one step is as follows:

[0032] 1) Treatment of the ITO conductive substrate (2.5 cm × 2.5 cm): The substrate was ultrasonically cleaned with pure water, ethanol, and isopropanol for 10 minutes in sequence, and then treated with an ultraviolet ozone cleaner for 20 minutes;

[0033] 2) Preparation of the perovskite solution: Weigh 1 mmol of FAPbI 3 , 0.2 mmol of methylammonium chloride (MACl), dissolve it with 1 mL of a binary solvent of 2-methoxyethanol and 1,3-dimethyl-2-imidazolidinone (v:v = 7:1), and then add 0.1 mmol

[0034] 1,4-butanesultone and 0.001 mmol of [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid, and shake until completely dissolved to obtain a mixed solution of perovskite and hole transport material;

[0035] 3) Spin-coat the mixed solution of perovskite and hole transport material obtained in step 2) on the ITO conductive substrate at a rotation speed of 5000 revolutions per minute for 45 seconds, and then anneal at 120 °C for 30 minutes to obtain a perovskite layer / hole transport layer heterojunction, where the thickness of the perovskite layer is about 800 nm, the band gap is about 1.52 eV, and the thickness of the hole transport layer is about 2 nm.

[0036] The flow chart for preparing the perovskite layer / hole transport layer heterojunction and the schematic diagram of the product structure in this example are as shown in Figure 1As shown in Figure A. By adding 1,4-butanesultone to the system, high-quality perovskite and hole layer thin films can be obtained simultaneously through a single-step spin coating process. The SEM morphology of the heterojunction cross-section obtained in this example is as shown in Figure 2 Figure A. It can be seen that the hole transport molecules aggregate between the perovskite and the ITO conductive substrate, forming a hole transport layer thin film with a thickness of approximately 2 nm. The upper surface of the heterojunction was bonded to another piece of glass using ultraviolet curable glue, and the heterojunction thin film was peeled off from the original substrate to expose the lower surface. The SEM morphology image is as shown in Figure 2 Figure B. It can be seen that the hole layer is uniform and dense, and conformally grows on the ITO substrate. Its surface perfectly replicates the morphology of the ITO and binds well to the perovskite layer.

[0037] On the surface of the above perovskite thin film, 30 nm of C 60 、8 nm of bathocuproine, and 100 nm of silver electrode were sequentially deposited to obtain a p-i-n structured perovskite solar cell. The JV curve of the obtained p-i-n perovskite solar cell is as shown in Figure 4 Figure, with a reverse scan efficiency reaching 25.11% and a forward scan efficiency reaching 24.90%.

[0038] Comparative Example 1

[0039] A method for preparing a perovskite layer-hole transport layer, which is different from Example 1 in that 1,4-butanesultone is not added, and the remaining steps are the same as those in Example 1.

[0040] The process flow and product structure schematic diagram of the perovskite layer / hole transport layer heterojunction prepared in this comparative example are as shown in Figure 1 Figure B. Using the method of this comparative example, pores are likely to form between the perovskite layer and the substrate, and the hole layer is uneven and not dense.

[0041] The SEM morphology images of the heterojunction cross-section and the peeled lower surface (the peeling method is the same as that in Example 1) obtained in this comparative example are as shown in Figure 2 Figures C and D. It can be seen that it is difficult for the hole transport molecules to aggregate between the perovskite and the ITO layer. The cross-section morphology shows that many voids appear at the cross-section connection. The morphology of the lower interface (Figure Figure 2 D) shows that the hole transport molecules cannot completely cover the perovskite layer, and some perovskite is exposed, which is not conducive to the extraction and transport of carriers.

[0042] On the surface of the perovskite thin film in this comparative example, 30 nm of C 60 、8 nm of bathocuproine, and 100 nm of silver electrode were sequentially deposited to obtain a p-i-n structured perovskite solar cell. The JV curve of the obtained p-i-n perovskite solar cell is as shown in Figure 4 Figure, and its reverse scan efficiency is only 21.81%, and the forward scan efficiency is 21.50%, which is much lower than that in Example 1.

[0043] Comparative Example 2

[0044] A method for preparing a perovskite layer - hole transport layer layer by layer, the specific steps are as follows:

[0045] 1) Treatment of ITO conductive substrate (2.5 cm × 2.5 cm): The substrate was ultrasonically cleaned in pure water, ethanol, and isopropanol for 10 minutes in sequence, and then treated with an ultraviolet ozone cleaner for 20 minutes;

[0046] 2) Preparation of hole material solution: Weigh 0.001 mmol of [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphoric acid and dissolve it in 1 mL of ethanol to obtain a hole material solution;

[0047] 3) Preparation of perovskite solution: Weigh 1 mmol of FAPbI 3 , 0.2 mmol of methylammonium chloride, and dissolve them in 1 mL of a binary solvent of 2-methoxyethanol and 1,3-dimethyl-2-imidazolidinone (v:v = 7:1), and shake until completely dissolved to obtain a perovskite solution;

[0048] 4) Spin-coat the hole material solution obtained in step 2) on the ITO conductive substrate at a rotation speed of 4000 revolutions per minute for 20 seconds, and anneal at 100 °C for 10 minutes. The thickness of the obtained hole transport layer is about 2 nm;

[0049] 5) Spin-coat the perovskite solution obtained in step 3) on the hole transport layer obtained in step 4) at a rotation speed of 5000 revolutions per minute for 45 seconds, and then anneal at 120 °C for 30 minutes to obtain a perovskite layer / hole transport layer heterojunction, where the thickness of the perovskite layer is about 800 nm and the band gap is about 1.52 eV.

[0050] The SEM morphology of the surface of the hole transport layer obtained in step 4) in this comparative example is as Figure 3 shown. It can be seen that during layer-by-layer deposition, the molecules of [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphoric acid agglomerated, resulting in many protrusions on the film surface, which is not conducive to interface connection and carrier transport at the interface. Deposit 30 nm of C 60 , 8 nm of bathocuproine, and 100 nm of silver electrode on the surface of the perovskite film in this comparative example in sequence to obtain a p-i-n structure perovskite solar cell. The JV curve of the obtained p-i-n perovskite solar cell is as Figure 4 shown. Its reverse scan efficiency is 24.22%, and its forward scan efficiency is 23.65%. Its efficiency is lower than that of Example 1.

[0051] Example 2

[0052] A method for efficiently preparing a perovskite layer-hole transport layer in one step, which is different from Example 1 in that in step 3), the method of coating the mixed solution of perovskite and hole transport material on the ITO conductive substrate is different. Through blade coating printing, the distance between the blade tip and the substrate is 150 μm, the air knife pressure is 0.4 Mpa, and the printing speed is 7 mm / s. The remaining steps are the same as those in Example 1. The thickness of the obtained perovskite layer is about 600 nm, and the thickness of the hole transport layer is about 2 nm.

[0053] In this comparative example, 30 nm of C is sequentially deposited on the surface of the perovskite thin film 60 , 8 nm of bathocuproine, and 100 nm of silver electrode are obtained to form a p-i-n structure perovskite solar cell. The JV curve of the p-i-n perovskite solar cell obtained in this comparative example is as Figure 4 shown. The reverse scan efficiency is 24.33%, and the forward scan efficiency is 23.82%. The cell performance is close to that of Example 1. It is confirmed that blade coating can still form a high-quality perovskite layer / hole transport layer heterojunction.

Claims

1. A method for efficiently preparing a perovskite layer-hole transport layer in one step, characterized in that: The specific steps are as follows: 1) preparing a perovskite precursor solution, then adding 1,4-butane sultam and a hole transport material to the solution, shaking until completely dissolved, to obtain a mixed solution of perovskite and hole transport material; 2) coating the mixed solution of the perovskite and the hole transport material obtained in step 1) on a clean ITO conductive substrate to obtain a precursor film, and then annealing the obtained precursor film to obtain a composite film of a lower hole transport layer and an upper perovskite layer.

2. The method for efficiently preparing a perovskite layer-hole transport layer in one step according to claim 1, characterized in that: Step 1) The preparation method of the perovskite precursor solution is: weigh the corresponding FAPbI3, MA x FA 1-x Pb(I y Br 1-y )3 or Cs x FA 1- x Pb(I y Br 1-y )3 raw material, add methylamine chloride accounting for 5-40% of the molar amount of PbI2 in the raw material, dissolve it in a solvent to obtain a perovskite precursor solution, the concentration of the perovskite precursor solution is 1-2M.

3. The method for efficiently preparing a perovskite layer-hole transport layer in one step according to claim 1, characterized in that: Step 1) The hole transport material is one of (2-(9H-carbazole-9-yl)ethyl)phosphonic acid, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphonic acid and [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid.

4. The method for efficiently preparing a perovskite layer-hole transport layer in one step according to claim 1, characterized in that: Step 1) In the mixed solution of the perovskite and the hole transport material, the concentration of 1,4-butane sultam is 0.05-0.2M, and the concentration of the hole transport material is 0.001-0.01M.

5. The method for efficiently preparing a perovskite layer-hole transport layer in one step according to claim 1, characterized in that: Step 2) annealing treatment process conditions are: annealing temperature is 120-130° C., and annealing time is 20-40 minutes.

6. Use of the method for efficiently preparing a perovskite layer-hole transport layer in one step according to any one of claims 1 to 5 in preparing a perovskite solar cell.

7. The perovskite layer-hole transport layer prepared by the method for efficiently preparing a perovskite layer-hole transport layer in one step according to any one of claims 1 to 5, characterized in that: The band gap of the perovskite layer is 1.55 to 1.77 eV, the thickness of the perovskite layer is 500 to 900 nm, and the thickness of the hole layer is 1 to 3 nm.

8. A perovskite solar cell comprising the perovskite layer-hole transport layer according to claim 7, characterized in that: The invention comprises an ITO conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, a buffer layer and a top electrode which are stacked in sequence from bottom to top.

9. A method for preparing a perovskite solar cell according to claim 8, characterized in that: The specific steps are as follows: 1) preparing a perovskite precursor solution, then adding 1,4-butane sultam and a hole transport material to the solution, shaking until completely dissolved, to obtain a mixed solution of perovskite and hole transport material; 2) coating the mixed solution of the perovskite and the hole transport material obtained in step 1) on a clean ITO conductive substrate to obtain a precursor film, and then annealing the obtained precursor film to obtain a composite film of a lower hole transport layer and an upper perovskite layer; 3) An electron transport layer, a buffer layer and a top electrode are sequentially deposited on the surface of the composite film of the lower hole transport layer and the upper perovskite layer obtained in step 2) to obtain a perovskite solar cell.

10. The method for preparing a perovskite solar cell according to claim 9, characterized in that: Step 3) The electron transport layer is C 60 Or tin oxide, with a thickness of 20 to 30 nm, the buffer layer is bathocuproin, with a thickness of 10 to 20 nm, and the top electrode is silver or copper, with a thickness of 80 to 100 nm.

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