Perovskite cell with 12-hsa passivated perovskite layer and preparation method

Abstract

The application relates to a perovskite battery adopting a 12-HSA passivated perovskite layer and a preparation method. The perovskite battery adopts a 12-hydroxystearic acid hydrogel as a passivation layer to passivate the perovskite layer. The preparation method comprises the following steps: sequentially preparing an electron transport layer, a perovskite layer, a passivation layer, a hole transport layer and an electrode layer on a substrate, wherein the preparation process of the passivation layer is as follows: preparing a 12-HSA solution; the 12-HSA solution is prepared by mixing 12-hydroxystearic acid and isopropyl alcohol; then, the 12-HSA solution is uniformly spread on the perovskite layer, and the preparation of the passivation layer is completed on the perovskite layer. The perovskite battery of the application can form a physical protection layer on the perovskite layer through the design of the passivation layer formed by 12-HSA, can reduce the defect state density of the perovskite transport layer, and can improve the long-term stability and moisture resistance of the perovskite battery device; the preparation method is simple and reasonable.

Description

Technical Field

[0001] This invention relates to the field of perovskite solar cells, and in particular to a perovskite solar cell employing a 12-HSA passivated perovskite layer and its preparation method. Background Technology

[0002] Since perovskite solar cells first achieved an efficiency of 3.8% in 2009, perovskite materials have become a hot semiconductor material, with their highest photoelectric efficiency surpassing that of silicon cells. However, silicon cells are still the most widely used in the market, mainly because the poor stability and short lifespan of perovskite solar cells have limited their commercial development. There are two main reasons affecting device stability: First, water and oxygen in the air directly enter the perovskite layer, causing it to be eroded by moisture. Moisture, heat, and light all severely affect device stability, leading to a rapid decrease in photoelectric conversion efficiency (PCE). Second, grain boundary defects in perovskite are also a significant factor affecting stability. During the fabrication process, continuous post-processing techniques inevitably introduce various defects at grain boundaries and surfaces, such as under-coordinated Pb. 2+ and I - Defects, especially interface defects, can affect charge transport. The interaction between charge carriers and defects can deflect charge carriers and slow down their transport speed. At the same time, defects can also become charge recombination centers and water and oxygen channels, eroding the perovskite layer and causing energy loss and decreased device stability.

[0003] To address the stability issue, a series of solutions were implemented. These included adding additives to the perovskite precursor solution, adjusting the perovskite composition, and improving encapsulation technology, all of which can alleviate the stability problem to some extent. However, unencapsulated perovskite solar cells still exhibit low stability and low photoelectric conversion efficiency under high humidity or direct contact with moisture conditions.

[0004] Therefore, designing a perovskite solar cell with high humidity stability has become an urgent problem to be solved. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a perovskite solar cell employing a 12-HSA passivation layer. Through the design of the passivation layer formed by 12-HSA, a physical protective layer can be formed on the perovskite layer, reducing the defect state density of the perovskite transport layer and improving the long-term stability and moisture resistance of the perovskite solar cell device. The fabrication method is simple and the design is reasonable.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a perovskite battery using a 12-HSA passivation perovskite layer, wherein 12-hydroxystearic acid hydrogel is used as a passivation layer to passivate the perovskite layer.

[0007] The perovskite solar cell further includes a substrate, an electron transport layer, a perovskite layer, a hole transport layer, and an electrode layer arranged sequentially; the passivation layer is disposed between the perovskite layer and the hole transport layer.

[0008] The substrate is made of conductive glass; the electron transport layer is prepared from a SnO2 precursor solution.

[0009] The perovskite layer was prepared from a PbI2 precursor solution and a FAI solution.

[0010] The hole transport layer was prepared from a Spiro-OMeTAD solution.

[0011] The preparation method of perovskite solar cells specifically includes the following steps:

[0012] S1. Prepare an electron transport layer on a substrate;

[0013] S2. Prepare a perovskite layer on the electron transport layer in step S1;

[0014] S3. Prepare a passivation layer on the perovskite layer in step S2;

[0015] The passivation layer is prepared as follows: a 12-HSA solution is prepared, which is a mixture of 12-hydroxystearic acid and isopropanol; then, the 12-HSA solution is uniformly spread on the perovskite layer, thus completing the preparation of the passivation layer on the perovskite layer.

[0016] S4. Prepare a hole transport layer on the passivation layer in step S3;

[0017] S5. An electrode layer is prepared on the hole transport layer in step S4.

[0018] The specific process of step S1 is as follows: clean the substrate and dry it; prepare the SnO2 precursor solution; coat the SnO2 precursor solution onto the surface of the substrate, anneal it, and then cool it to room temperature, thus completing the preparation of the electron transport layer on the substrate.

[0019] The specific process of step S2 is as follows: prepare a PbI2 precursor solution and a FAI solution; wherein, the PbI2 precursor solution is a mixture of PbI2, DMF, and DMSO, and is fully dissolved; the FAI solution is a mixture of FAI, MABr, MACl, and isopropanol, and is fully dissolved; then, take the PbI2 precursor solution and coat it onto the electron transport layer of step S1, anneal it, and then cool it to room temperature to obtain a yellow PbI2 film on the electron transport layer; then take the FAI solution and coat it onto the PbI2 film, anneal it, and then cool it to room temperature to obtain a blue-black perovskite layer on the electron transport layer.

[0020] The specific process of step S4 is as follows: Prepare Spiro-OMeTAD solution; wherein, Spiro-OMeTAD solution is prepared by mixing Spiro-OMeTAD, chlorobenzene, TBP, Li-TSFI, and Co(III)-TFSI; then, take Spiro-OMeTAD solution and coat it onto the passivation layer, that is, a hole transport layer is obtained on the passivation layer.

[0021] The specific process of step S5 is as follows: the electrode material is deposited onto the hole transport layer by vacuum evaporation, and the electrode layer is obtained on the hole transport layer.

[0022] Advantages of the present invention: The perovskite solar cell of the present invention using a 12-HSA passivation perovskite layer can form a physical protective layer on the perovskite layer through the design of the passivation layer formed by 12-HSA, and can reduce the defect state density of the perovskite transport layer, thereby improving the long-term stability and moisture resistance of the perovskite solar cell device; the preparation method is simple and the design is reasonable. Attached Figure Description

[0023] Figure 1 A schematic diagram of a perovskite solar cell using a 12-HSA passivated perovskite layer is shown in the embodiment.

[0024] Among them, 1-substrate, 2-electron transport layer, 3-perovskite layer, 4-passivation layer, 5-hole transport layer, and 6-electrode layer.

[0025] Figure 2 The results of high-temperature testing are given for the semi-finished products prepared in step S3 of the experimental example and the semi-finished products prepared in step S2 of the comparative example.

[0026] Figure 3 The results are from aging tests conducted on the perovskite solar cells prepared in the experimental example and the perovskite solar cells prepared in the comparative example. Detailed Implementation

[0027] To enhance understanding of the present invention, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. These embodiments are only used to explain the invention and do not limit the scope of protection of the invention.

[0028] Example

[0029] like Figure 1 As shown, this embodiment provides a perovskite solar cell with a 12-HSA passivated perovskite layer, including a substrate 1, an electron transport layer 2, a perovskite layer 3, a passivation layer 4, a hole transport layer 5, and an electrode layer 6 arranged sequentially; wherein, 12-hydroxystearic acid hydrogel is used as the passivation layer 4 to passivate the perovskite layer 3.

[0030] In this embodiment of the perovskite battery, a 12-hydroxystearic acid (12-HSA) hydrogel solution is used to form a passivation layer on the perovskite layer 3. The passivation layer plays two main roles: 1. From a physical reaction perspective: Due to the inherent properties of the hydrogel, 12-HSA molecules self-assemble, and hydroxyl and carbonyl groups cross-link together through hydrogen bonds, forming a fibrous network structure on the surface of the perovskite layer. As a physical protective layer, it does not affect hole transport and blocks water molecules and oxygen from the air from reaching the perovskite layer. At the same time, the long carbon chains of 12-HSA molecules are hydrophobic. Under high temperature conditions, moisture in the air will reach the passivation layer first. The hygroscopic effect of the hydrogel firmly encapsulates the hemihydrate molecules in the network structure, thereby preventing moisture from eroding the perovskite layer, reducing the degradation of the perovskite battery, and thus enabling the unencapsulated device to maintain long-term stability and moisture resistance under high temperature conditions. 2. From a chemical reaction perspective: The 12-HSA molecule acts as a passivating agent. It contains both carbonyl and hydroxyl functional groups. The carbonyl group, as a Lewis base, can react with uncoordinated Pb. 2+ The hydroxyl groups can form hydrogen bonds with perovskite, therefore, 12-HSA can effectively passivate Pb. 2+ and I - The defects caused by these molecules slow down the nucleation of perovskite crystals, reduce the growth rate of perovskite, increase the grain size of perovskite, and improve the carrier transport capacity, thus greatly mitigating the degradation of perovskite. In other words, 12-HSA molecules can not only form a physical protective layer for the perovskite layer, but also undergo Lewis acid-base reactions with the perovskite layer at the chemical level, reducing the defect state density.

[0031] In a perovskite battery employing a 12-HSA passivated perovskite layer according to this embodiment, preferably, the substrate 1 is made of conductive glass; the electron transport layer 2 is prepared from a SnO2 precursor solution; the perovskite layer 3 is prepared from a PbI2 precursor solution and a FAI solution; and the hole transport layer 5 is prepared from a Spiro-OMeTAD solution.

[0032] This embodiment also provides a method for fabricating a perovskite solar cell using a 12-HSA passivated perovskite layer, specifically including the following steps:

[0033] S1. An electron transport layer 2 is prepared on substrate 1;

[0034] S2. Prepare a perovskite layer 3 on the electron transport layer 2 in step S1;

[0035] S3. A passivation layer 4 is prepared on the perovskite layer 3 in step S2;

[0036] The passivation layer 4 is prepared as follows: a 12-HSA solution is prepared; the 12-HSA solution is a mixture of 12-hydroxystearic acid and isopropanol; then, the 12-HSA solution is uniformly spread on the perovskite layer 3, that is, the passivation layer 4 is prepared on the perovskite layer 3.

[0037] S4. Prepare a hole transport layer 5 on the passivation layer 4 in step S3;

[0038] S5. An electrode layer 6 is prepared on the hole transport layer 5 in step S4.

[0039] In the perovskite battery preparation method of this embodiment, the specific process of step S1 is as follows: clean the substrate 1 and dry it; prepare the SnO2 precursor solution; coat the SnO2 precursor solution onto the surface of the substrate, anneal it, and then cool it to room temperature, that is, the electron transport layer 2 is prepared on the substrate 1.

[0040] In the perovskite solar cell preparation method of this embodiment, the specific process of step S2 is as follows: prepare a PbI2 precursor solution and a FAI solution; wherein, the PbI2 precursor solution is a mixture of PbI2, DMF, and DMSO, and is fully dissolved; the FAI solution is a mixture of FAI, MABr, MACl, and isopropanol, and is fully dissolved; then, take the PbI2 precursor solution and coat it onto the electron transport layer 2 of step S1, anneal it, and then cool it to room temperature to obtain a yellow PbI2 film on the electron transport layer 2; then take the FAI solution and coat it onto the PbI2 film, anneal it, and then cool it to room temperature to obtain a blue-black perovskite layer 3 on the electron transport layer 2.

[0041] In the perovskite battery preparation method of this embodiment, the specific process of step S4 is as follows: prepare Spiro-OMeTAD solution; wherein, Spiro-OMeTAD solution is prepared by mixing Spiro-OMeTAD, chlorobenzene, TBP (4-tert-butylpyridine), Li-TSFI, and Co(III)-TFSI; then, take Spiro-OMeTAD solution and coat it on passivation layer 4, that is, hole transport layer 5 is obtained on passivation layer 4.

[0042] In the perovskite battery preparation method of this embodiment, the specific process of step S5 is as follows: the electrode material is deposited onto the hole transport layer 5 by vacuum evaporation, and the electrode layer 6 is obtained on the hole transport layer 5.

[0043] Test case

[0044] Fabrication of perovskite solar cells:

[0045] S1, Cleaning of conductive glass, and preparation of electron transport layer 2

[0046] Place a certain number of 2cm*2cm conductive glass pieces into a container, and add appropriate amounts of detergent, deionized water, acetone, isopropanol, and alcohol in sequence. Clean the glass pieces in an ultrasonic cleaner for about 30 minutes. After ultrasonic cleaning, place the glass pieces in a 60℃ drying oven for 60 minutes.

[0047] Take 100 μL of SnO2 (tin oxide) precursor solution onto the cleaned conductive glass, spin coat it at 3000 rpm for 30 s using a spin coater, then anneal it at 150℃ for 30 min, and finally cool it in air to obtain the electron transport layer.

[0048] S2, Preparation of the perovskite layer

[0049] Preparation of PbI2 precursor solution: Dissolve 1.3 mol of PbI2 (lead iodide) powder in 950 μL of DMF (N,N-dimethylformamide) and 50 μL of DMSO (dimethyl sulfoxide) solvent, and stir at 70℃ until dissolved.

[0050] Preparation of FAI solution: Dissolve 60 mg of FAI (formamidinium iodide), 9 mg of MABr (methylamine bromide), and 6 mg of MACl (methylamine chloride) powder in 1 mL of IPA (isopropanol) solution and stir at room temperature until dissolved;

[0051] Take 50 μL of PbI2 precursor solution and spin coat it onto the electron transport layer at 1500 rpm for 30 s using a spin coater. Anneal at 70 °C for 15 min and cool to obtain a yellow PbI2 film. Then, take 100 μL of organic salt solution and spin coat it onto the electron transport layer at 1500 rpm for 30 s using a spin coater. Anneal at 135 °C for 25 min. The color gradually turns blue-black. After cooling to room temperature, the perovskite layer is obtained.

[0052] S3, Preparation of passivation layer

[0053] Preparation of 12-HSA solution: Dissolve 5 mg of 12-HSA (12-hydroxystearic acid) in 1 mL of IPA (isopropanol), stir at room temperature, and the 12-HSA additive solution is obtained.

[0054] Take 100 μL of the solution and spread it evenly on the perovskite transport layer in step (3) of Example 1. Spin coat it for 30 seconds at a speed of 1500 rpm using a spin coater. No annealing is required.

[0055] S4. Preparation of the hole transport layer

[0056] Preparation of Spiro-OMeTAD solution: Weigh 0.0723 g of Spiro-OMeTAD (2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene) powder and dissolve it in 1 mL of chlorobenzene solvent. Then, add 28 μL of TBP (4-tert-butylpyridine) solution, 18 μL of Li-TSFI (lithium bis(trifluoromethanesulfonyl)imide) solution and 28 μL of Co(III)-TFSI (cobalt-based complex of bis(trifluoromethanesulfonyl)imide) solution to each solution and stir at room temperature for 15 min to obtain the Spiro-OMeTAD solution.

[0057] Take 50 μL of Spiro-OMeTAD solution and spin coat it at 2000 rpm for 20 s using a spin coater. No annealing is required to obtain the hole transport layer.

[0058] S5. Preparation of the electrode layer

[0059] Using vacuum evaporation, when the required vacuum level is reached, gold particles are deposited onto the hole transport layer at a stable current rate until they reach approximately 100 nm, thus obtaining the electrode layer; this completes the fabrication of the perovskite solar cell.

[0060] Comparative Example

[0061] In the comparative example, the same steps and parameters as in the experimental example were used. The difference was that in the comparative example, the passivation layer preparation process in step S3 was removed, and the hole transport layer in step S4 was prepared directly on the perovskite layer in step S2.

[0062] High-temperature tests were conducted on the semi-finished products obtained in step S3 of the experimental example and the semi-finished products obtained in step S2 of the comparative example. The test method was as follows: the corresponding samples were placed under a humidity of 80-85% RH (relative humidity) for twenty days, and the surface morphology changes were observed on the first, fifth, tenth, and twentieth days. The test results were as follows: Figure 2 As shown, after being stored at 80-85% RH (relative humidity) for 20 days, the semi-finished product of the example that was passivated with 12-HSA did not show obvious decomposition (remaining blue-black), while the semi-finished product of the comparative example that was not passivated with 12-HSA decomposed on the 5th day under the same humidity conditions. After 20 days, it could be found that the blue-black perovskite layer was almost completely decomposed, exposing the PbI2 film (which changed from blue-black to yellow).

[0063] Aging experiments were conducted on the perovskite solar cells prepared in the experimental examples and the comparative examples. The experimental method involved placing the corresponding samples under a relative humidity of 80-85% RH for twenty days, and testing the photoelectric conversion efficiency on the first, fifth, tenth, and twentieth days. The experimental results are as follows: Figure 3As shown, under 80-85% RH (relative humidity) conditions, the PCE (conversion efficiency) of the comparative perovskite solar cell without 12-HSA passivation completely decayed in just 5 days, indicating a rapid decomposition rate of the perovskite layer. In contrast, the PCE of the perovskite solar cell in the example, passivated with 12-HSA, ultimately retained 80% of its initial PCE. Close observation revealed that after a slight decrease on day 5, the efficiency of the perovskite solar cell using the example with 12-HSA passivation stabilized at around 80% of its initial efficiency for the following 15 days. This indicates that the perovskite solar cell with 12-HSA passivation exhibits the highest tolerance to humidity. These results are attributed to the hydrophobicity of the long carbon chains in the 12-HSA molecule and the physical protective layer formed by the intermolecular hydrogen bond network on the perovskite, which slows down the degradation of the perovskite solar cell. Simultaneously, the chemical effect of the passivation defects in the 12-HSA molecule also enhances humidity stability.

[0064] The above embodiments should not limit the present invention in any way. All technical solutions obtained by equivalent substitution or equivalent conversion fall within the protection scope of the present invention.

Claims

1. A method for preparing a perovskite solar cell using a perovskite layer passivated with 12-hydroxystearic acid, characterized in that: The preparation method specifically includes the following steps: S1. Prepare an electron transport layer on a substrate; S2. Prepare a perovskite layer on the electron transport layer in step S1; S3. Prepare a passivation layer on the perovskite layer in step S2; The passivation layer is prepared as follows: a 12-hydroxystearic acid solution is prepared; the 12-hydroxystearic acid solution is a mixture of 12-hydroxystearic acid and isopropanol; then, the 12-hydroxystearic acid solution is uniformly spread on the perovskite layer, thus completing the preparation of the passivation layer on the perovskite layer. S4. Prepare a hole transport layer on the passivation layer in step S3; S5. An electrode layer is prepared on the hole transport layer in step S4.

2. The method for preparing a perovskite solar cell using a 12-hydroxystearic acid passivated perovskite layer according to claim 1, characterized in that: The substrate is made of conductive glass; The electron transport layer was prepared from a SnO2 precursor solution.

3. The method for preparing a perovskite solar cell using a 12-hydroxystearic acid passivated perovskite layer according to claim 1, characterized in that: The perovskite layer was prepared from a PbI2 precursor solution and a FAI solution.

4. The method for preparing a perovskite solar cell using a 12-hydroxystearic acid passivated perovskite layer according to claim 1, characterized in that: The hole transport layer was prepared from a Spiro-OMeTAD solution.

5. The method for preparing a perovskite solar cell using a 12-hydroxystearic acid passivated perovskite layer according to claim 2, characterized in that: The specific process of step S1 is as follows: clean the substrate and dry it; prepare the SnO2 precursor solution; coat the SnO2 precursor solution onto the surface of the substrate, anneal it, and then cool it to room temperature, thus completing the preparation of the electron transport layer on the substrate.

6. The method for preparing a perovskite solar cell using a 12-hydroxystearic acid passivated perovskite layer according to claim 3, characterized in that: The specific process of step S2 is as follows: prepare a PbI2 precursor solution and a FAI solution; wherein, the PbI2 precursor solution is a mixture of PbI2, DMF, and DMSO, and is fully dissolved; the FAI solution is a mixture of FAI, MABr, MACl, and isopropanol, and is fully dissolved; then, take the PbI2 precursor solution and coat it onto the electron transport layer of step S1, anneal it, and then cool it to room temperature to obtain a yellow PbI2 film on the electron transport layer; then take the FAI solution and coat it onto the PbI2 film, anneal it, and then cool it to room temperature to obtain a blue-black perovskite layer on the electron transport layer.

7. The method for preparing a perovskite solar cell using a 12-hydroxystearic acid passivated perovskite layer according to claim 4, characterized in that: The specific process of step S4 is as follows: prepare Spiro-OMeTAD solution; wherein, Spiro-OMeTAD solution is prepared by mixing Spiro-OMeTAD, chlorobenzene, TBP, Li-TSFI, and Co(III)-TFSI; then, take Spiro-OMeTAD solution and coat it on the passivation layer, that is, a hole transport layer is obtained on the passivation layer.

8. The method for preparing a perovskite solar cell using a 12-hydroxystearic acid passivated perovskite layer according to claim 1, characterized in that: The specific process of step S5 is as follows: the electrode material is deposited onto the hole transport layer by vacuum evaporation, and the electrode layer is obtained on the hole transport layer.

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