Laser repair method for perovskite layers

Abstract

This invention relates to a laser repair method for perovskite layers. The perovskite layer has several grain boundary cracks; these grain boundary cracks include deep grain boundary cracks; the depth of the deep grain boundary cracks is at least 200 nm. The repair method is a dual-energy pulse repair, specifically: 1) First, a first nanosecond infrared laser with an energy density of 0.25–0.5 J / cm² is used to scan the perovskite layer until instantaneous micro-area melting forms on the surface of the perovskite layer, filling the grain boundary cracks, thus completing one repair; 2) Then, a second nanosecond infrared laser with an energy density of 0.1–0.2 J / cm² is used for a second repair; the repetition frequency of the first and second nanosecond infrared lasers is 20–100 kHz, and the pulse width is 10–50 ns. The technical problem to be solved is how to provide a laser repair method for perovskite layers capable of repairing deep cracks.

Description

Technical Field

[0001] This invention belongs to the field of perovskite technology, and in particular relates to a laser repair method for perovskite layers. Background Art

[0002] Perovskite solar cells possess enormous development potential and application prospects due to their significant advantages such as low cost, high conversion efficiency, and abundant material resources. However, current limitations in perovskite thin film fabrication processes result in numerous grain boundary cracks on the surface of the prepared perovskite films, leading to a decrease in photoelectric conversion efficiency and posing a significant threat to the long-term stability of the cells.

[0003] In current technological systems, single-pulse lasers are often used to eliminate grain boundary cracks on the surface of perovskite thin films. However, when using single-pulse lasers to repair deep cracks, excessively high laser energy can cause over-melting of the perovskite layer surface, damaging its surface structure and properties. This makes it difficult to achieve the ideal quality of the perovskite thin film, failing to meet the requirements for efficient and stable production of perovskite solar cells. Summary of the Invention

[0004] The main objective of this invention is to provide a laser repair method for perovskite layers. The technical problem to be solved is how to provide a laser repair method that can repair deep cracks in perovskite layers and make their surfaces smooth.

[0005] The objective of this invention and the technical problem it solves are achieved by the following technical solution. According to this invention, a laser repair method for a perovskite layer is proposed, wherein the perovskite layer has several grain boundary cracks; the grain boundary cracks include: deep grain boundary cracks; the depth of the deep grain boundary cracks is at least 200 nm; the repair method is a dual-energy pulse repair, specifically:

[0006] 1) First, use a first nanosecond infrared laser with an energy density of 0.25 to 0.5 J / cm² to scan the perovskite layer until instantaneous micro-area melting is formed on the surface of the perovskite layer, and after filling the grain boundary cracks, one repair is completed;

[0007] 2) Then, a second nanosecond infrared laser with an energy density of 0.1 to 0.2 J / cm² is used for secondary repair; the repetition frequency of the first nanosecond infrared laser and the second nanosecond infrared laser is 20 to 100 kHz, and the pulse width is 10 to 50 ns.

[0008] Preferably, in the aforementioned repair method, the grain boundary cracks further include: shallow grain boundary cracks; the depth of the shallow grain boundary cracks is less than 200 nm.

[0009] Preferably, the aforementioned repair method, wherein the method specifically includes:

[0010] 1) Confirm that the area with the grain boundary cracks on the surface of the perovskite layer is the area to be repaired, and set the scan path;

[0011] 2) The first nanosecond infrared laser is used to heat the area to be repaired along the scanning path until instantaneous micro-area melting is formed on the surface of the perovskite layer, filling the grain boundary cracks. After cooling and crystallization, one repair is completed.

[0012] 3) Use the second nanosecond infrared laser to scan along the scanning path to perform secondary repair until the surface roughness of the area to be repaired is <30nm, and the repair is completed.

[0013] Preferably, in the aforementioned repair method, the scanning path is a straight line scan or a serpentine path scan; the scanning speed is 50–200 mm / s.

[0014] Preferably, in the aforementioned repair method, the wavelengths of the first nanosecond infrared laser and the second nanosecond infrared laser are 532 nm, the spot size is 20–100 μm, and the overlap rate is 70–90%.

[0015] Preferably, in the aforementioned repair method, the perovskite surface further includes several pinholes.

[0016] The objective of this invention and the solution to its technical problems are further achieved by the following technical solution. A perovskite solar cell according to this invention includes a perovskite layer; the perovskite layer is prepared by repairing several grain boundary cracks using a dual-energy pulse repair method; the grain boundary cracks include deep grain boundary cracks; the depth of the deep grain boundary cracks is at least 200 nm; the repair method includes:

[0017] 1) First, use a first nanosecond infrared laser with an energy density of 0.25 to 0.5 J / cm² to scan the perovskite layer until instantaneous micro-area melting is formed on the surface of the perovskite layer, and after filling the grain boundary cracks, one repair is completed;

[0018] 2) Then, a second nanosecond infrared laser with an energy density of 0.1 to 0.2 J / cm² is used for secondary repair; the repetition frequency of the first nanosecond infrared laser and the second nanosecond infrared laser is 20 to 100 kHz, and the pulse width is 10 to 50 ns.

[0019] Preferably, in the aforementioned perovskite solar cell, the grain boundary cracks further include: shallow grain boundary cracks and / or pinholes; the depth of the shallow grain boundary cracks is less than 200 nm.

[0020] Preferably, in the aforementioned perovskite solar cell, the wavelengths of the first nanosecond infrared laser and the second nanosecond infrared laser are 532 nm, the spot size is 20–100 μm, and the overlap rate is 70–90%.

[0021] Preferably, in the aforementioned perovskite solar cell, the perovskite layer is obtained by the aforementioned laser repair method for perovskite layers.

[0022] By employing the above technical solution, the laser-induced perovskite layer reconstruction dual-pulse gradient repair method proposed in this invention has at least the following advantages:

[0023] The present invention employs a dual-energy pulse repair method to repair grain boundary cracks in the perovskite layer with a depth greater than 200 nm, thereby improving the structural integrity of the perovskite layer and thus enhancing the electrical performance of perovskite solar cells.

[0024] This invention discloses a method for repairing energy pulses, which involves first performing a high-energy first nanosecond infrared laser for initial repair, followed by a second nanosecond infrared laser with lower energy for secondary repair. During the first repair, the first nanosecond infrared laser scans the perovskite layer, precisely forming a transient micro-melting state on the perovskite layer surface. In this process, surface tension and the Marangoni effect work synergistically to drive the redistribution of the molten material, efficiently filling microscopic defects and precisely reconstructing the grain boundary structure, thereby repairing deep grain boundary cracks. However, after the surface tension and the Marangoni effect work synergistically, the perovskite layer surface becomes rough, resulting in uneven pits. Therefore, this invention performs a secondary repair, which can reduce the surface roughness to <30nm, thus achieving a systematic repair of perovskite layer defects and improving the electrical performance of perovskite solar cells.

[0025] The nanosecond infrared laser disclosed in this invention features rapid heating and cooling, enabling the repair of perovskite layers in a short time and improving production efficiency. Employing an energy dual-body gradient method, it can repair deep cracks exceeding 200 nm in depth while reducing surface pinhole density by over 90%. Furthermore, laser-induced grain rearrangement reduces defects in the perovskite layer, increases crystallinity, and creates a more uniform surface morphology, thereby enhancing carrier mobility, reducing energy loss, and ultimately improving the overall performance of the battery.

[0026] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Attached Figure Description

[0027] Figure 1This is a schematic diagram of the laser repair method for perovskite layers described in this invention.

[0028] Figure 2 This is a schematic diagram of the grain boundary crack depth described in this invention.

[0029] Among them, 1. Titanium mineral layer, 2. Grain boundary cracks, and 3. Depth. Detailed Implementation

[0030] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a laser-induced perovskite layer reconstruction dual-pulse gradient repair method proposed according to the present invention. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0031] This invention proposes a laser repair method for a perovskite layer, wherein the perovskite layer has several grain boundary cracks; the grain boundary cracks include deep grain boundary cracks; the depth of the deep grain boundary cracks is at least 200 nm; the repair method is a dual-energy pulse repair, specifically:

[0032] 1) First, use a first nanosecond infrared laser with an energy density of 0.25 to 0.5 J / cm² to scan the perovskite layer until instantaneous micro-area melting is formed on the surface of the perovskite layer, and after filling the grain boundary cracks, one repair is completed;

[0033] 2) Then, a second nanosecond infrared laser with an energy density of 0.1 to 0.2 J / cm² is used for secondary repair; the repetition frequency of the first nanosecond infrared laser and the second nanosecond infrared laser is 20 to 100 kHz, and the pulse width is 10 to 50 ns.

[0034] like Figure 1 As shown, this invention discloses the energy density, repetition frequency, and pulse width of a first nanosecond infrared laser. This laser can provide sufficient energy to form instantaneous micro-region melting on the surface of the perovskite layer. Under the combined effect of surface tension and the Marangoni effect, it can effectively fill deep grain boundary cracks (at least 200 nm in depth) without causing excessive damage to the perovskite layer due to excessive energy, thus ensuring the protection of the material's structure during the repair process.

[0035] This invention discloses a secondary repair method using a second nanosecond infrared laser with an energy density of 0.1 to 0.2 J / cm². The lower energy density allows for fine processing of the surface after the first repair, further optimizing the repair effect, eliminating high-frequency thermal stress, and thus achieving a smooth surface, i.e., a surface roughness of <30 nm.

[0036] This invention discloses a nanosecond infrared laser. By limiting its repetition frequency and pulse width, it can achieve rapid heating and cooling effects, and can complete the repair of the perovskite layer in a short time, thereby improving production efficiency.

[0037] Preferably, in the aforementioned repair method, the grain boundary cracks further include: shallow grain boundary cracks and / or pinholes; the depth of the shallow grain boundary cracks is less than 200 nm.

[0038] The repair method disclosed in this invention can not only repair deep cracks with a depth greater than 200 nm, but also repair shallow grain boundary cracks and pinholes.

[0039] It is worth noting that, such as Figure 2 As shown, the depth 3 disclosed in this invention is the depth measured downwards from the repair surface of the perovskite layer 1.

[0040] Preferably, the aforementioned repair method, wherein the method specifically includes:

[0041] 1) Confirm that the area with the grain boundary cracks on the surface of the perovskite layer is the area to be repaired, and set the scan path;

[0042] 2) The first nanosecond infrared laser is used to heat the area to be repaired along the scanning path until instantaneous micro-area melting is formed on the surface of the perovskite layer, filling the grain boundary cracks. After cooling and crystallization, one repair is completed.

[0043] 3) Use the second nanosecond infrared laser to scan along the scanning path to perform secondary repair until the surface roughness of the area to be repaired is <30nm, and the repair is completed.

[0044] In one repair, the present invention uses nanosecond infrared laser to locally heat the perovskite. By utilizing the high energy density and short pulse characteristics of the laser, instantaneous micro-region melting can be formed on the surface of the perovskite. Then, the surface tension and Marangoni effect are used to promote the redistribution of the molten material, fill the micro-defects and reconstruct the grain boundary structure, thereby achieving the repair of defects in the perovskite layer.

[0045] In the secondary repair, the present invention uses a nanosecond infrared laser with low energy density for scanning, which can eliminate the high-frequency thermal stress generated in the primary repair, thereby achieving a smooth surface.

[0046] Preferably, in the aforementioned repair method, the scanning path is a straight line scan or a serpentine path scan; the scanning speed is 50–200 mm / s.

[0047] The scanning path disclosed in this invention can be implemented using linear or serpentine scanning methods as needed, ensuring uniform scanning of the laser beam across the perovskite layer surface. This avoids prolonged lingering at the same location, reduces heat accumulation, and guarantees full coverage of the repair area. The scanning speed can be adjusted according to laser parameters and thin film characteristics, typically between 50 and 200 mm / s.

[0048] Preferably, in the aforementioned repair method, the wavelengths of the first nanosecond infrared laser and the second nanosecond infrared laser are 532 nm, the spot size is 20–100 μm, and the overlap rate is 70–90%.

[0049] This invention utilizes the absorption characteristics of tantalum materials, employing a 532nm nanosecond laser. Leveraging its high energy density and ultrashort pulse characteristics, it achieves precise localized thermal effects on perovskite thin films. The laser action creates instantaneous micro-melting zones on the material surface. Under the synergistic effect of surface tension and Marangoni convection, the molten material undergoes directional migration and redistribution, effectively filling micropores and reconstructing the grain boundary network, while simultaneously avoiding thermal damage to the substrate material.

[0050] This invention selects appropriate parameters for the wavelength, repetition frequency, pulse width, and energy density of a nanosecond infrared laser based on the characteristics of the perovskite layer and the repair requirements. By precisely controlling these parameters, the degree of interaction between the laser and the perovskite layer can be adjusted, achieving different degrees of repair on the perovskite layer.

[0051] Preferably, in the aforementioned repair method, the light spots of the first nanosecond infrared laser and the second nanosecond infrared laser are rectangular light spots.

[0052] This invention discloses a nanosecond infrared laser with a rectangular spot size for repair processing. The spot size can be adjusted according to actual needs, generally between 20 and 100 μm. For the repair of large-area perovskite layers, a larger spot size can be selected to improve processing efficiency; while for the repair of local defects, a smaller spot size can be used for precise repair.

[0053] Preferably, in the aforementioned repair method, the perovskite surface further includes several pinholes.

[0054] This invention also proposes a perovskite solar cell, comprising a perovskite layer; the perovskite layer is prepared by repairing several grain boundary cracks on its surface using a dual-energy pulse repair method; the grain boundary cracks include deep grain boundary cracks; the depth of the deep grain boundary cracks is at least 200 nm; the repair method includes:

[0055] 1) First, use a first nanosecond infrared laser with an energy density of 0.25 to 0.5 J / cm² to scan the perovskite layer until instantaneous micro-area melting is formed on the surface of the perovskite layer, and after filling the grain boundary cracks, one repair is completed;

[0056] 2) Then, a second nanosecond infrared laser with an energy density of 0.1 to 0.2 J / cm² is used for secondary repair; the repetition frequency of the first nanosecond infrared laser and the second nanosecond infrared laser is 20 to 100 kHz, and the pulse width is 10 to 50 ns.

[0057] Preferably, in the aforementioned perovskite solar cell, the grain boundary cracks further include: shallow grain boundary cracks and / or pinholes; the depth of the shallow grain boundary cracks is less than 200 nm.

[0058] Preferably, in the aforementioned perovskite solar cell, the wavelengths of the first nanosecond infrared laser and the second nanosecond infrared laser are 532 nm, the spot size is 20–100 μm, and the overlap rate is 70–90%.

[0059] Preferably, in the aforementioned perovskite solar cell, the perovskite layer is obtained by the aforementioned laser repair method for perovskite layers.

[0060] The present invention will be further described below with reference to specific embodiments, but this should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0061] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0062] Example 1

[0063] A laser repair method for a perovskite layer, wherein the perovskite layer has several grain boundary cracks; the grain boundary cracks include deep grain boundary cracks; the depth of the deep grain boundary cracks is 200 nm; the repair method is a dual-energy pulse repair, specifically:

[0064] 1) Confirm that the area with the grain boundary cracks on the surface of the perovskite layer is the area to be repaired, and set the scanning path to a straight line scan or a serpentine path scan, with a scanning speed of 50 mm / s;

[0065] 2) Use a first nanosecond infrared laser with an energy density of 0.25 J / cm² to heat the area to be repaired along the scanning path until instantaneous micro-area melting is formed on the surface of the perovskite layer, filling the grain boundary cracks, and then cooling and crystallizing to complete one repair.

[0066] 3) Use a second nanosecond infrared laser with a speed of 0.1 J / cm² to scan along the scanning path for secondary repair until the surface roughness of the area to be repaired is <30 nm, at which point the repair is complete.

[0067] The first nanosecond infrared laser and the second nanosecond infrared laser have a repetition frequency of 20 kHz, a pulse width of 10 ns, a wavelength of 532 nm, a spot size of 20 μm, and an overlap rate of 70%.

[0068] Example 2

[0069] A laser repair method for a perovskite layer, wherein the perovskite layer has several grain boundary cracks; the grain boundary cracks include deep grain boundary cracks; the depth of the deep grain boundary cracks is 200 nm; the repair method is a dual-energy pulse repair, specifically:

[0070] 1) Confirm that the area with the grain boundary cracks on the surface of the perovskite layer is the area to be repaired, set the scanning path to a straight line scan or a serpentine path scan, and the scanning speed to 100 mm / s;

[0071] 2) Use a first nanosecond infrared laser with an energy density of 0.3 J / cm² to heat the area to be repaired along the scanning path until instantaneous micro-area melting is formed on the surface of the perovskite layer, filling the grain boundary cracks, and then cooling and crystallizing to complete one repair.

[0072] 3) Use a second nanosecond infrared laser with a speed of 0.15 J / cm² to scan along the scanning path for secondary repair until the surface roughness of the area to be repaired is <30 nm. The repair is then complete.

[0073] The first nanosecond infrared laser and the second nanosecond infrared laser have a repetition frequency of 60 kHz, a pulse width of 30 ns, a wavelength of 532 nm, a spot size of 60 μm, and an overlap rate of 80%.

[0074] Example 3

[0075] A laser repair method for a perovskite layer, wherein the perovskite layer has several grain boundary cracks; the grain boundary cracks include deep grain boundary cracks; the depth of the deep grain boundary cracks is 200 nm; the repair method is a dual-energy pulse repair, specifically:

[0076] 1) Confirm that the area with the grain boundary cracks on the surface of the perovskite layer is the area to be repaired, set the scanning path to a straight line scan or a serpentine path scan, and the scanning speed to 200 mm / s;

[0077] 2) Use a first nanosecond infrared laser with an energy density of 0.5 J / cm² to heat the area to be repaired along the scanning path until instantaneous micro-area melting is formed on the surface of the perovskite layer, filling the grain boundary cracks, and then cooling and crystallizing to complete one repair.

[0078] 3) Use a second nanosecond infrared laser with a speed of 0.2 J / cm² to scan along the scanning path for secondary repair until the surface roughness of the area to be repaired is <30 nm, at which point the repair is complete.

[0079] The first nanosecond infrared laser and the second nanosecond infrared laser have a repetition frequency of 100 kHz, a pulse width of 50 ns, a wavelength of 532 nm, a spot size of 100 μm, and an overlap rate of 90%.

[0080] Example 4

[0081] Compared to Example 2, the depth of the deep grain boundary cracks in Example 4 is 300 nm.

[0082] Example 5

[0083] Compared with Example 2, Example 5 also includes shallow grain boundary cracks with a depth of 100 nm.

[0084] Example 6

[0085] Compared to Example 5, Example 6 also includes a pinhole.

[0086] Comparative Example 1

[0087] A method for repairing a perovskite layer using a single-pulse laser, specifically as follows: the perovskite layer has several grain boundary cracks; the grain boundary cracks include: deep grain boundary cracks; the depth of the deep grain boundary cracks is 200 nm;

[0088] 1) Confirm that the area with the grain boundary cracks on the surface of the perovskite layer is the area to be repaired, set the scanning path to a straight line scan or a serpentine path scan, and the scanning speed to 200 mm / s;

[0089] 2) A nanosecond infrared laser with an energy density of 0.3 J / cm² is used to heat the area to be repaired along the scanning path, cool and crystallize, and complete one repair.

[0090] Comparing the repaired perovskite layers of Example 2 and Comparative Example 1, it can be seen that, for repairing deep grain boundary cracks of the same depth of 200 nm, the surface roughness of Comparative Example 1 is greater than that of Example 2. In the above embodiments, the descriptions of each embodiment have different focuses; for parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0091] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A laser repair method for perovskite layers, characterized in that, The perovskite layer has several grain boundary cracks; the grain boundary cracks include deep grain boundary cracks; the depth of the deep grain boundary cracks is at least 200 nm; the repair method is dual-energy pulse repair, specifically: 1) First, use a first nanosecond infrared laser with an energy density of 0.25 to 0.5 J / cm² to scan the perovskite layer until instantaneous micro-area melting is formed on the surface of the perovskite layer, and after filling the grain boundary cracks, one repair is completed; 2) Then, a second nanosecond infrared laser with an energy density of 0.1 to 0.2 J / cm² is used for secondary repair; the repetition frequency of the first nanosecond infrared laser and the second nanosecond infrared laser is 20 to 100 kHz, and the pulse width is 10 to 50 ns.

2. The repair method according to claim 1, characterized in that, The grain boundary cracks also include: shallow grain boundary cracks and / or pinholes; the depth of the shallow grain boundary cracks is less than 200 nm.

3. The repair method according to claim 1, characterized in that, The method specifically includes: 1) Confirm that the area with the grain boundary cracks on the surface of the perovskite layer is the area to be repaired, and set the scan path; 2) The first nanosecond infrared laser is used to heat the area to be repaired along the scanning path until instantaneous micro-area melting is formed on the surface of the perovskite layer, filling the grain boundary cracks. After cooling and crystallization, one repair is completed. 3) Use the second nanosecond infrared laser to scan along the scanning path to perform secondary repair until the surface roughness of the area to be repaired is <30nm, and the repair is completed.

4. The repair method according to claim 3, characterized in that, The scanning path is either a straight line scan or a serpentine path scan; the scanning speed is 50–200 mm / s.

5. The repair method according to any one of claims 1 to 4, characterized in that, The first nanosecond infrared laser and the second nanosecond infrared laser have a wavelength of 532nm, a spot size of 20-100μm, and an overlap rate of 70-90%.

6. The repair method according to any one of claims 1 to 4, characterized in that, The perovskite surface also includes several pinholes.

7. A perovskite solar cell, characterized in that, It includes a perovskite layer; the perovskite layer is prepared by repairing several grain boundary cracks using a dual-energy pulse repair method. The grain boundary cracks include: deep grain boundary cracks; the depth of the deep grain boundary cracks is at least 200 nm; the repair method includes: 1) First, use a first nanosecond infrared laser with an energy density of 0.25 to 0.5 J / cm² to scan the perovskite layer until instantaneous micro-area melting is formed on the surface of the perovskite layer, and after filling the grain boundary cracks, one repair is completed; 2) Then, a second nanosecond infrared laser with an energy density of 0.1 to 0.2 J / cm² is used for secondary repair; the repetition frequency of the first nanosecond infrared laser and the second nanosecond infrared laser is 20 to 100 kHz, and the pulse width is 10 to 50 ns.

8. The perovskite solar cell according to claim 7, characterized in that, The grain boundary cracks also include: shallow grain boundary cracks and / or pinholes; the depth of the shallow grain boundary cracks is less than 200 nm.

9. The perovskite solar cell according to claim 7 or 8, characterized in that, The first nanosecond infrared laser and the second nanosecond infrared laser have a wavelength of 532nm, a spot size of 20-100μm, and an overlap rate of 70-90%.

10. The perovskite solar cell according to claim 7 or 8, characterized in that, The perovskite layer is obtained by a laser repair method for a perovskite layer as described in any one of claims 1 to 6.

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