Method and device for repairing perovskite layer of solar cell by laser

Abstract

The application discloses a laser repairing method and device for a perovskite layer of a solar cell piece, and the repairing method comprises the following steps: S1, detecting and determining all defect areas on the perovskite layer; S2, dropping perovskite precursor liquid on each defect area, and spreading the perovskite precursor liquid droplets to cover the defect areas; S3, placing the solar cell piece semi-finished product on a moving platform, presetting a path of the moving platform, a laser repairing path and a light spot shape and size, and ensuring that a laser scanning area can cover all the defect areas; S4, emitting blue laser to the perovskite precursor liquid, driving the moving platform and the laser to move according to the preset path, and making the perovskite precursor liquid of the defect area rapidly react to form perovskite crystals; and S5, cleaning and drying the surface of the perovskite layer, and completing the repairing. In the application, the blue laser can rapidly make the perovskite precursor liquid chemically change and rapidly form perovskite crystals, and the perovskite layer is rapidly repaired.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, specifically to a laser repair method and device for the perovskite layer of a solar cell. Background Technology

[0002] With the continuous advancement and upgrading of solar cell technology, third-generation solar cells have emerged. Third-generation solar cells refer to perovskite crystal structure solar cells, utilizing perovskite-type organometal halide semiconductors as light-absorbing materials to form a new concept of solar cell with a perovskite crystal structure, called perovskite solar cells. The perovskite layer refers to a crystalline material with the general chemical formula ABX3, typically a cubic or octahedral structure. In a perovskite crystal, the A ion is located at the center of the cubic unit cell, surrounded by 12 X ions to form a coordinated cubic octahedron, with a coordination number of 12; the B ion is located at the corner of the cubic unit cell, surrounded by 6 X ions to form a coordinated octahedron. A is generally an organic amine ion (such as CH3NH3+, NH=CHNH3+), B is generally a divalent metal ion (such as Pb2+, Sn2+, etc.), and X represents a halide ion (Cl-, Br-, I-). Because of their appropriate ionic radii, the smaller organic ions can adjust the gaps between inorganic ions, allowing inorganic metal halides to form a continuous octahedral framework, resulting in a relatively regular crystal form that approximates a cube, and thus exhibiting high photoelectric conversion efficiency.

[0003] Perovskite solar cell structure as follows Figure 1 As shown, a top electrode 102 (etched silver paste layer), an electron transport layer 103 (N-type semiconductor material layer), a perovskite layer 104, a hole transport layer 105 (P-type semiconductor material layer), and a bottom electrode 106 (Ag or Au layer) are sequentially arranged upwards on a substrate 101 to form the overall structure of a perovskite solar cell. When a perovskite photovoltaic cell receives sunlight, holes generated in the internal electric field move through the hole transport layer to the metal electrode to form the cathode, while electrons generated in the internal electric field move to the transparent conductive oxide glass (FTO) to form the anode. Ultimately, a potential difference is formed inside the perovskite photovoltaic cell, which generates current when connected to an external circuit.

[0004] This novel perovskite solar cell achieves an energy conversion rate more than twice that of traditional crystalline silicon monocrystalline solar cells, exceeding 40%. This significantly reduces the cost of using solar cells. Solar cells made with this novel perovskite as the structural layer can directly convert approximately half of sunlight into electricity, significantly improving energy efficiency. Furthermore, perovskite-based solar cells do not require an electric field to generate current, reducing the amount of materials needed. Recent scientific research shows that perovskite solar cells exhibit excellent power generation performance and good stability in the long-duration, high-temperature-difference, strong ultraviolet, and low-pressure near-space environment.

[0005] Although perovskite solar cells have promising applications, the production of the perovskite layer is prone to defects and inhomogeneities in the local structure, as well as instability in the crystal structure of the local perovskite layer. These issues can lead to reduced lifespan and performance of the solar panel, lower conversion efficiency, and significant material waste and underutilization of resources.

[0006] Therefore, there is a need to develop a laser repair method for the perovskite layer of solar cells that does not affect other manufacturing processes or damage the silver paste layer. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide a laser repair method for the perovskite layer of solar cells that does not affect other manufacturing processes or damage the silver paste layer. This method repairs localized inhomogeneities, structural alterations, and instabilities in the perovskite layer of solar panels, thereby improving the stability and conversion efficiency of the perovskite layer.

[0008] The technical solution of this invention is: a laser repair method for the perovskite layer of a solar cell, characterized by comprising the following steps:

[0009] S1. Inspect the semi-finished solar cell with a perovskite layer on top, and detect all defect areas on the perovskite layer.

[0010] S2. Place the semi-finished solar cell on a low-temperature workbench below 0°C, add perovskite precursor liquid to each defect area, and blow the perovskite precursor liquid droplets to cover the corresponding defect areas.

[0011] S3. Place the semi-finished solar cell on the moving platform, preset the path of the moving platform, the laser repair path, and the shape and size of the laser spot to ensure that the laser scanning area can cover all defect areas;

[0012] S4. A blue laser is emitted onto the perovskite precursor liquid according to the preset spot shape and size, driving the moving platform and the laser to move along the preset path, so that the perovskite precursor liquid in the defect area is rapidly heated and reacted to form perovskite crystals.

[0013] S5. Clean and dry the surface of the perovskite layer. Repair is complete.

[0014] Preferably, in step S1, the detection includes: placing a semi-finished solar cell with a perovskite layer on top above an LED ultraviolet light source plate; the LED ultraviolet light source plate emits ultraviolet light from the bottom of the semi-finished solar cell to irradiate the perovskite layer; acquiring an image of the perovskite layer; and analyzing the image to determine the defect area of ​​the perovskite layer. In this invention, a color camera is installed above the perovskite solar cell; the camera takes a picture, and the image is transmitted to spectral analysis software; the software analyzes the image and calculates the defect area of ​​the perovskite layer on the perovskite solar cell.

[0015] Furthermore, in step S1, the LED ultraviolet light source panel emits ultraviolet light with a wavelength of 300nm to 400nm and an average ultraviolet light power of 0.1 to 0.3W.

[0016] Preferably, in step S2, the semi-finished solar cell is placed on a workbench at -10 to -15°C, and perovskite precursor liquid is dripped onto the center of each defect area. Nitrogen gas is blown out by rotating an air knife to disperse the perovskite precursor liquid droplets and cover the corresponding defect areas. After dispersion, the thickness of the perovskite precursor liquid droplets is 50 to 300 μm.

[0017] Preferably, in step S4, the blue laser forms a square spot with a side length of 1 to 10 mm on the perovskite precursor solution.

[0018] Preferably, in step S4, the blue laser is emitted by a semiconductor blue laser, and after being processed by a blue laser repair head, it is irradiated onto the perovskite precursor liquid. The semiconductor blue laser emits a laser with a wavelength of 440nm to 460nm, an output beam circularity greater than 98%, a beam divergence angle less than 0.5 milliradians, and an average blue laser power of 20 to 60W.

[0019] Furthermore, the blue light repair head includes a beam expander, a collimator, a shaping lens group, a reflecting lens group, and a spot size adjuster arranged sequentially along the optical path. The shaping lens group includes one or more shaping lenses for adjusting the shape of the spot, and the reflecting lens group includes a pair of reflecting mirrors for projecting the spot onto the spot size adjuster.

[0020] Preferably, in step S4, the perovskite precursor solution is rapidly heated to 120-150°C within 1-3 seconds by irradiation to undergo a reaction.

[0021] Preferably, in step S5, the surface of the perovskite layer is cleaned and then dried with nitrogen.

[0022] The principle of each step in this invention is as follows:

[0023] Step S1 detects local defects in the perovskite layer by utilizing the extremely high absorption and conversion rates of ultraviolet light in the perovskite crystal layer. Ultraviolet light is absorbed in the normal area of ​​the perovskite layer, but not in the defective area. A color camera is used to take pictures from above, and the non-absorbed area shows relatively strong ultraviolet light. The relatively strong ultraviolet light area is analyzed and processed by spectral analysis software to form the defect area, and the size and outline of the defect area are calculated.

[0024] Step S2 uses a low-temperature worktable to rapidly crystallize the perovskite precursor solution, thereby inhibiting its activity and preventing chemical changes. A rotary air knife is used to blow nitrogen gas, ensuring that each defective area is uniformly covered with the perovskite precursor solution containing organic polymers.

[0025] Step S4 employs laser repair. The principle behind this is the high stability, uniform energy, high efficiency, high precision, and rapid heating of the laser. It can raise the material temperature to 120-150 degrees Celsius within a very short time (1-3 seconds), with a heat-affected zone of less than 0.1 mm. While other areas remain at normal temperatures, the target material has already undergone chemical changes. A blue laser is used because its wavelength can rapidly induce chemical changes in the perovskite precursor solution, quickly forming perovskite crystals.

[0026] In step S4, the function of the blue light repair head is to output blue laser light in a uniform energy field, ensuring consistent energy density across the entire light spot area, and to adjust the spot size without altering the energy density.

[0027] This invention also provides a repair device for laser repair methods of the perovskite layer of any of the above-mentioned solar cells, including a semiconductor blue laser and a base. The base is provided with a Y-axis moving stage that can move horizontally in the Y direction. The top of the Y-axis moving stage is provided with a moving platform for placing the solar cell. The base is provided with a bracket. The top of the bracket is provided with an X-axis moving stage that can move horizontally in the X direction. The X-axis moving stage is provided with a Z-axis moving stage that can move vertically in the Z direction. A blue laser repair head is installed on the Z-axis moving stage to correspond with the solar cell below. The blue laser repair head is connected to the semiconductor blue laser through a transmission optical fiber. The blue laser repair head includes a beam expander, a collimating lens, a shaping lens group, a reflecting mirror group, and a spot size adjuster arranged sequentially along the optical path. The shaping lens group includes one or more shaping mirrors for adjusting the spot shape. The reflecting mirror group includes a pair of reflecting mirrors for projecting the spot onto the spot size adjuster.

[0028] The beneficial effects of this invention are:

[0029] 1. Compared with traditional heating stage methods, it does not require overall repair of the perovskite layer, but can achieve local repair. It can quickly heat the perovskite precursor solution to between 120 and 150 degrees Celsius within 1 to 3 seconds. Moreover, the laser acts directly on the organic polymer perovskite precursor solution as a heat source, which is less likely to cause uneven heating due to substrate issues. Laser non-contact processing avoids secondary damage to the perovskite crystals caused by contact processes during the repair process. Its repair process is simple and can be directly inserted into the existing perovskite layer process to repair defective areas, thereby improving yield and perovskite layer preparation rate.

[0030] 2. Due to the short formation cycle of perovskite crystal structure (within seconds), high fluidity, and narrow temperature window for crystal formation, blue light repair is used. The perovskite crystal stability is excellent. The perovskite precursor solution has the highest absorption rate for blue lasers, can heat up rapidly, and has very stable laser energy. Its short repair cycle makes it more capable of forming stable perovskite crystals.

[0031] 3. Compared with other methods, this process uses a laser with low power requirements as the heating source, simplifying the process setup. This offers fundamental advantages in reducing production costs and energy consumption. Attached Figure Description

[0032] Figure 1 A schematic diagram of the overall structure of a perovskite solar cell in the prior art.

[0033] Figure 2 This is a schematic diagram showing that the solar cell in this invention is only fabricated up to the perovskite layer.

[0034] Figure 3 A schematic diagram of the defect area detected in the solar cell in step S1.

[0035] Figure 4 A schematic diagram of the perovskite precursor solution dripped onto the solar cell in step S2.

[0036] Figure 5 Schematic diagram of perovskite precursor solution aeration in step S2

[0037] Figure 6 This is a schematic diagram of the repair device of the present invention.

[0038] Figure 7 Schematic diagram of the blue light therapy head structure

[0039] Wherein: 101-Substrate; 102-Top electrode; 103-Electron transport layer; 104-Perovskite layer; 105-Hole transport layer; 106-Bottom electrode; 201-Semi-finished solar cell; 301-LED ultraviolet light source plate; 302-Ultraviolet light; 303-Color camera; 401-Defect area; 402-Perovskite precursor solution; 403-Diffused perovskite precursor solution; 501-Semiconductor blue laser; 502-Transmission fiber; 503-Blue light repair head; 504-Beam expander; 505-Collimator; 506-Shaping lens group; 507-Reflector group; 508-Spot size adjuster; 1-Base; 2-Bracket; 3-Y-axis moving stage; 4-X-axis moving stage; 5-Z-axis moving stage; 6-Moving platform. Detailed Implementation

[0040] To further understand the present invention, preferred embodiments are described below with reference to examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims. Unless otherwise specified, all materials used in the examples are commercially available products, and all methods used are conventional methods in the art. The perovskite precursor solution used in this invention is consistent with the formulation used in the production of the perovskite layer of the solar cell to be repaired, and is a commercially available perovskite precursor solution containing organic polymers.

[0041] like Figures 6-7 As shown, the repair device used in this invention includes a semiconductor blue laser 501 and a base 1. The base 1 is provided with a Y-axis moving stage 3 that can move horizontally in the Y direction. The top of the Y-axis moving stage 3 is provided with a moving platform 6 for placing solar cells. The base 1 is provided with a bracket 2. The top of the bracket 2 is provided with an X-axis moving stage 4 that can move horizontally in the X direction. The X-axis moving stage 4 is provided with a Z-axis moving stage 5 that can move vertically in the Z direction. A blue light repair head 503 is installed on the Z-axis moving stage 5 to correspond with the solar cells below. The blue light repair head 503 is connected to the semiconductor blue laser 501 through a transmission optical fiber 502. The blue light repair head 503 includes a beam expander 504, a collimating lens 505, a shaping lens group 506, a reflecting mirror group 507, and a spot size adjuster 508 arranged sequentially along the optical path. The shaping lens group 506 includes one or more shaping mirrors for adjusting the shape of the spot. The reflecting mirror group 507 includes a pair of reflecting mirrors for projecting the spot onto the spot size adjuster 508.

[0042] The function of the blue light repair head 503 is to output blue laser light in a uniform energy field, ensuring consistent energy density in each area within the light spot range, and adjusting the spot size without changing the energy density. In this embodiment, the blue laser light emitted by the semiconductor blue laser 501 is transmitted to the blue light repair head 503 via the transmission fiber 502. The laser light passes through the beam expander 503, whose lens is coated with an anti-reflection film with a wavelength of 440nm to 460nm, expanding the beam by 8 times to a circular spot with a diameter of 8 mm; it then passes through the collimating lens 505, whose lens is coated with an anti-reflection film with a wavelength of 440nm to 460nm, collimating the spot to perpendicular incidence; finally, it passes through the shaping lens group 506, which includes four shaping lenses, each coated with a wavelength of 440nm to 460nm. The anti-reflective coating and the shaping mirrors are specially designed with curved surfaces. When combined, they shape the blue light spot into a square spot with a side length of 10 mm (the number and shape of the shaping mirror group 506 can be selected and adjusted according to actual needs). The square spot with a side length of 10 mm passes through the mirror group 507, each mirror having a 45-degree reflective coating on one side with a wavelength of 440 nm to 460 nm, and reaches the spot size adjuster 508. The spot size adjuster 508 adjusts the size of the spot to a square spot with a side length between 1 and 10 mm without changing the energy density.

[0043] The 501 semiconductor blue laser has a wavelength of 440nm to 460nm and is a semiconductor blue laser. It emits blue laser with an average power of 20 to 60W. Its output beam circularity is greater than 98%, its beam divergence angle is less than 0.5 milliradians, and its laser has no peak power. The 502 transmission fiber has a 400-micron core. The reason for using a blue laser is that the wavelength of the blue laser can quickly cause a chemical change in the perovskite precursor solution of organic polymers to rapidly form perovskite crystals.

[0044] In the repair device of the present invention, the movement paths of the moving platform 6 and the blue light repair head 503 can be set by software, that is, the movement of the moving platform 6 is achieved by controlling the Y-axis moving stage 3 and the movement of the blue light repair head 503 is achieved by controlling the X-axis moving stage 4.

[0045] The solar cell semi-finished product 201 that needs to be repaired according to this invention is as follows. Figure 2 As shown, the solar cell semi-finished product 201 is only processed up to the perovskite layer 104. That is, the solar cell semi-finished product 201 includes, from bottom to top, a substrate 101, a top electrode 102, an electron transport layer 103, and a perovskite layer 104.

[0046] The specific dimensions of the repaired solar cell semi-finished product 201 in this embodiment are: 200*200 mm in length and width, and 1.2 mm in thickness. During the manufacturing process, perovskite crystals were not formed in some areas due to the lack of coverage by the perovskite precursor solution. The ultraviolet LED surface light source used has a wavelength of 300nm to 400nm and an average ultraviolet light power of 0.1 to 0.3W. The semiconductor blue laser 501 is a semiconductor fiber-coupled laser M450-Y120 with a rated power of 100W and a center wavelength of 450 nm.

[0047] The method for repairing the semi-finished solar cell 201 using the above repair equipment includes the following steps:

[0048] S1, such as Figure 3 As shown, the semi-finished solar cell 201 with a perovskite layer 104 on top is first placed above an LED ultraviolet light source plate 301 that emits ultraviolet light. When powered on, the LED ultraviolet light source plate 301 emits ultraviolet light 302, which irradiates the bottom of the semi-finished solar cell 201. The light passes through the top electrode 102 and the electron transport layer 103 to reach the perovskite layer 104. A color camera 303 is installed above the semi-finished solar cell 201 to take pictures. The color camera 303 takes pictures and the pictures are transmitted to the spectral analysis software. The software calculates that the defect area 401 on the perovskite layer 104 is a rectangle of 3*4 mm (in this embodiment, there is only one defect area; other samples may detect multiple defect areas).

[0049] S2. Place the semi-finished solar cell 201 on a -15℃ workbench (perovskite layer 104 facing upwards). At the center of the 3*4 mm rectangular defect area 401, as shown... Figure 4 As shown, perovskite precursor solution 402 is dropped on the surface. Nitrogen gas is then blown out using a rotary air knife to disperse the perovskite precursor solution, covering a 3*4 mm rectangular defect area 401. The diffused perovskite precursor solution 403 is as follows: Figure 5 As shown, the thickness is between 50 and 300 micrometers.

[0050] S3. Move the semi-finished solar cell 201 coated with perovskite precursor solution onto the moving platform 6. Preset the path of the moving platform 6 and the laser (i.e., blue light repair head 503) repair path in the software, that is, preset the travel parameters of the Y-axis moving stage 3 and the X-axis moving stage 4 so that the laser scanning path on the semi-finished solar cell 201 is a Z-shape, which just covers the defect area. Preset the blue light spot to a square light spot of equal density with a side length of 2 mm.

[0051] S4. Set the power of the semiconductor blue laser 501 to 38% of its rated power (i.e., an average power of 38W), and set the speed parameters of the Y-axis stage 3 and X-axis stage 4 to 55mm / s. Keep the Z-axis stage 5 stationary, adjust the spot size of the semiconductor blue laser repair head 503 to a 2mm equal-density square spot, and emit laser light. The blue laser light shines on the perovskite precursor liquid crystal. As the Y-axis stage 3 and X-axis stage 4 move along the preset path, the perovskite precursor liquid crystal rapidly heats up to 120-150 degrees Celsius within 1 second, undergoes a chemical reaction, and quickly forms a stable cubic octahedral perovskite crystal structure.

[0052] S5. After cleaning the surface of the perovskite layer 104 of the semi-finished solar cell 201, it is dried with nitrogen gas to remove the residual perovskite precursor liquid, and a uniform perovskite layer is formed, thus completing the repair.

[0053] This method can be used to repair perovskite layers in solar panels that are locally uneven, have localized structural changes, or are structurally unstable.

Claims

1. A method for laser repairing of a perovskite layer of a solar cell, characterized in that, Includes the following steps: S1. Inspect the semi-finished solar cell with a perovskite layer on top to identify all defect areas on the perovskite layer. S2. Place the semi-finished solar cell on a low-temperature workbench below 0°C, add perovskite precursor liquid to each defect area, and blow the perovskite precursor liquid droplets to cover the corresponding defect areas. S3. Place the semi-finished solar cell on the moving platform, preset the path of the moving platform, the laser repair path, and the shape and size of the laser spot to ensure that the laser scanning area can cover all existing defect areas. S4. A blue laser is emitted onto the perovskite precursor liquid according to the preset spot shape and size, driving the moving platform and the laser to move along the preset path, so that the perovskite precursor liquid in the defect area is rapidly heated and reacted to form perovskite crystals. S5. Clean and dry the surface of the perovskite layer. Repair is complete.

2. The laser repair method for the perovskite layer of a solar cell as described in claim 1, characterized in that, In step S1, the detection includes: placing a semi-finished solar cell with a perovskite layer on top above an LED ultraviolet light source plate, the LED ultraviolet light source plate emitting ultraviolet light from the bottom of the semi-finished solar cell to the perovskite layer, acquiring an image of the perovskite layer, and analyzing the image to obtain the defect area of ​​the perovskite layer.

3. The laser repair method for the perovskite layer of a solar cell as described in claim 2, characterized in that, In step S1, the LED ultraviolet light source panel emits ultraviolet light with a wavelength of 300nm to 400nm and an average ultraviolet light power of 0.1 to 0.3W.

4. The laser repair method for the perovskite layer of a solar cell as described in claim 1, characterized in that, In step S2, the semi-finished solar cell is placed on a workbench at -10 to -15°C. Perovskite precursor liquid is dripped onto the center of each defect area. Nitrogen gas is blown out by rotating an air knife to disperse the perovskite precursor liquid droplets and cover the corresponding defect areas. After dispersion, the thickness of the perovskite precursor liquid droplets is 50 to 300 μm.

5. The laser repair method for the perovskite layer of a solar cell as described in claim 1, characterized in that, In step S4, the blue laser forms a square spot with a side length of 1 to 10 mm on the perovskite precursor solution.

6. The laser repair method for the perovskite layer of a solar cell as described in claim 1, characterized in that, In step S4, the blue laser is emitted by a semiconductor blue laser (501), and after being processed by the blue laser repair head (503), it is irradiated onto the perovskite precursor liquid. The semiconductor blue laser (501) emits a laser with a wavelength of 440nm to 460nm, an output beam roundness greater than 98%, a beam divergence angle less than 0.5 milliradians, and an average blue laser power of 20 to 60W.

7. The laser repair method for the perovskite layer of a solar cell as described in claim 6, characterized in that, The blue light repair head (503) includes a beam expander (504), a collimator (505), a shaping lens group (506), a reflecting lens group (507), and a spot size adjuster (508) arranged sequentially along the optical path. The shaping lens group (506) includes one or more shaping lenses for adjusting the shape of the spot. The reflecting lens group (507) includes a pair of reflecting mirrors for projecting the spot onto the spot size adjuster (508).

8. The laser repair method for the perovskite layer of a solar cell as described in claim 1, characterized in that, In step S4, the perovskite precursor solution is rapidly heated to 120-150°C within 1-3 seconds by irradiation to undergo a reaction.

9. The laser repair method for the perovskite layer of a solar cell as described in claim 1, characterized in that, In step S5, the surface of the perovskite layer is cleaned and then dried with nitrogen.

10. A repair device used in the laser repair method for the perovskite layer of a solar cell as described in any one of claims 1 to 9, characterized in that, The device includes a semiconductor blue laser (501) and a base (1). The base (1) is equipped with a Y-axis moving stage (3) that can move horizontally in the Y direction. The top of the Y-axis moving stage (3) is equipped with a moving platform (6) for placing solar cells. The base (1) is equipped with a bracket (2). The top of the bracket (2) is equipped with an X-axis moving stage (4) that can move horizontally in the X direction. The X-axis moving stage (4) is equipped with a Z-axis moving stage (5) that can move vertically in the Z direction. The Z-axis moving stage (5) is equipped with a blue laser repair head (503) for connecting with the solar cells below. Corresponding to the pool plate, the blue light repair head (503) is connected to the semiconductor blue light laser (501) through the transmission optical fiber (502); the blue light repair head (503) includes a beam expander (504), a collimator (505), a shaping mirror group (506), a reflecting mirror group (507), and a spot size adjuster (508) arranged sequentially along the optical path direction. The shaping mirror group (506) includes one or more shaping mirrors for adjusting the shape of the spot, and the reflecting mirror group (507) includes a pair of reflecting mirrors for projecting the spot onto the spot size adjuster (508).

Images