A laser scribing method of carbon-based perovskite solar cells

Abstract

This application discloses a laser scribing method for carbon-based perovskite solar cells. The laser scribing method for carbon-based perovskite solar cells includes P1 scribing, P2 scribing, and P3 scribing. P3 scribing involves using a laser beam with an energy input lower than the melting threshold of the carbon back electrode material to perform at least two scribing operations on the carbon back electrode. After the first scribing operation, the laser beam is shifted a certain distance along the scribing width direction to perform a second scribing operation. The carbon back electrode is removed in the overlapping area of ​​the two scribing operations, while the carbon material retained in the non-overlapping areas still participates in carrier transport. This laser scribing method uses an offset overlapping etching technique to achieve laser scribing etching of the carbon back electrode. The energy input of a single etching operation is lower than the melting threshold of the carbon back electrode material, avoiding the crater effect caused by the melting and re-solidification of the carbon electrode. The two-batch overlapping etching effectively removes the carbon electrode, resulting in clean, residue-free, and thermally undamaged lines.

Description

Technical Field

[0001] This application relates to the field of perovskite solar cell technology, and in particular to a laser scribing method for carbon-based perovskite solar cells. Background Technology

[0002] Perovskite solar cells (PSCs) are considered one of the most promising next-generation photovoltaic technologies due to their excellent photoelectric conversion efficiency and low-cost solution processing characteristics. Among them, carbon-based perovskite solar cells use carbon materials such as conductive carbon paste, graphene, or carbon nanotubes to replace traditional precious metal counter electrodes such as Au and Ag. This significantly reduces material costs while effectively improving the device's operational stability in humid and hot environments thanks to the inherent hydrophobicity and chemical inertness of carbon materials, laying the material foundation for large-scale industrialization.

[0003] In the fabrication process of large-area perovskite photovoltaic modules, the interconnection between sub-cells is a core element determining the overall performance of the module. Currently, a three-line scribing process (P1-P2-P3) is commonly used to achieve a series structure. The P1 line is used to cleave the transparent conductive oxide (TCO) layer of the bottom electrode, forming lateral isolation between the sub-cells; the P2 line aims to remove the perovskite layer and carrier transport layer covering the TCO, exposing the bottom electrode to achieve electrical conduction between the sub-cells; and the P3 line is used to isolate the back electrodes of adjacent sub-cells to prevent back-current crosstalk.

[0004] Traditional mechanical scribing methods have inherent limitations in terms of processing accuracy, edge morphology control, and active layer damage suppression. They are prone to problems such as edge chipping, debris contamination, and heat-affected zone expansion, which severely restrict the improvement of component fill factor and conversion efficiency. Laser scribing, with its advantages of non-contact operation, high precision, high processing speed, and precisely controllable heat-affected zone, has become the preferred technical path for achieving fine scribing of high-performance perovskite modules.

[0005] However, the material system of carbon-based perovskite solar cells differs fundamentally from that of traditional metal electrode devices: carbon electrode layers are typically thick, reaching tens of micrometers, and are rigid, while perovskite materials are sensitive to moisture and oxygen and have limited thermal stability, making it difficult to directly transfer laser process parameters optimized for metal electrodes to carbon electrode layers. During the P3 scribing process of carbon-based devices, insufficient etching will result in carbon bridge residues and ineffective isolation between sub-cells; excessive etching will damage the underlying hole transport layer, perovskite light-absorbing layer, and even the TCO bottom electrode, causing a loss of effective power generation area or even open-circuit failure. In addition, the "crater"-like protrusions formed by the melting and resolidification of carbon electrodes caused by laser thermal effects can also disrupt interface contact and induce stability problems, and interface fluctuations can affect subsequent packaging processes.

[0006] Therefore, how to develop a dedicated laser scribing process that can cleanly peel off the P1, P2, and P3 lines without residue or thermal damage based on the material properties of each functional layer of carbon-based batteries remains a technical bottleneck that urgently needs to be overcome in the current industrial transformation process. Summary of the Invention

[0007] The purpose of this application is to provide an improved laser scribing method for carbon-based perovskite solar cells.

[0008] To achieve the above objectives, this application adopts the following technical solution:

[0009] This application discloses a laser scribing method for carbon-based perovskite solar cells, including scribing P1, scribing P2, and scribing P3. The scribing P3 method involves scribing the carbon back electrode at least twice using a laser beam with an energy input lower than the melting threshold of the carbon back electrode material. After the laser beam completes the first scribing, the laser beam is shifted a certain distance along the scribing width direction to perform a second scribing etching. The carbon back electrode is removed in the overlapping area of ​​the two scribings, while the carbon material retained in the non-overlapping area still participates in carrier transport.

[0010] In this process, a certain offset distance is used, specifically the offset distance of the second batch of lines. This offset distance is less than the line width, resulting in an overlapping area between the two batches of lines. The width of this overlapping area is the effective isolation line width formed by the P3 line. For example, if the width of the first batch of lines is 250 µm, and the second batch of lines is offset by 100 µm, the width of the second batch of lines remains 250 µm. This will ultimately produce an effective isolation line with a width of 150 µm, which is the line width minus the offset distance, and thus the overlapping area between the two batches of lines.

[0011] It should be noted that in the laser scribing method of this application, the purpose of the first batch of scribing (P3) is to partially peel off or loosen the carbon material. During the second batch of scribing, the peeled or loosened carbon material is more easily removed, thus achieving effective removal of the carbon back electrode. Because the energy input of the laser beam is lower than the melting threshold of the carbon back electrode material, each batch of scribing alone cannot effectively remove the carbon back electrode; it can only partially peel off or loosen the carbon material. Therefore, only the overlapping area of ​​the two batches of scribing can effectively remove the carbon back electrode, while the non-overlapping area will still retain some carbon material, which can still participate in carrier transport.

[0012] Understandably, the purpose of the first round of scribing is to partially peel off or loosen the carbon material. If the laser beam's energy input is only slightly below the melting threshold of the carbon back electrode material, then the first round of scribing only needs to be performed once. If the laser beam's energy input is significantly below the melting threshold of the carbon back electrode material, then the first round of scribing may need to be performed two or more times, to ensure that the carbon material is partially peeled off or loosened. Similarly, the second round of scribing can also be performed once, twice, or multiple times, depending on whether the overlapping area with the first round of scribing effectively removes the carbon back electrode.

[0013] In one implementation of this application, the P3 scribing uses a flat-top picosecond pulsed laser with an output power of 20-50 W, a pulse width of 120-160 ns, and a wavelength of 1000-1200 nm. For example, in some implementations, the P3 scribing uses an output power of 34 W, a pulse width of 144 ns, and a wavelength of 1064 nm.

[0014] In one implementation of this application, the P1 scribing involves etching the bottom electrode using a Gaussian spot picosecond pulsed laser with an output power of 3-5W, a pulse width of 15-25 ns, and a wavelength of 1000-1200 nm. For example, in some implementations, the P1 scribing uses an output power of 3.3 W or 4.4 W, a pulse width of 15-25 ns, and a wavelength of 1064 nm.

[0015] In one implementation of this application, the P2 scribing involves etching the perovskite functional layer using a Gaussian spot picosecond pulsed laser with an output power of 3-5W, a pulse width of 15-25 ns, and a wavelength of 1000-1200 nm. For example, in some implementations, the P2 scribing uses an output power of 3.3 W or 4.4 W, a pulse width of 15-25 ns, and a wavelength of 1064 nm.

[0016] In one implementation of this application, a carbon-based perovskite solar cell includes a bottom electrode, a perovskite functional layer, and a carbon back electrode stacked sequentially. The bottom electrode is an indium tin oxide thin film, and the perovskite functional layer includes an electron transport layer, a perovskite light-absorbing layer, and a hole transport layer.

[0017] In one implementation of this application, the thickness of the indium tin oxide (ITO) thin film is 100-200 nm. For example, the thickness of the ITO thin film is 100 nm, 150 nm, or 200 nm.

[0018] In one implementation of this application, the thickness of the carbon back electrode is 20-40 µm. For example, the thickness of the carbon back electrode is 20 µm, 25 µm, 30 µm, 35 µm, or 40 µm.

[0019] In one implementation of this application, P1 scribing further includes etching the bottom electrode, followed by ultrasonic cleaning and drying in preparation for subsequent P2 scribing.

[0020] In one implementation of this application, the P2 scribing method includes controlling the etching width by superimposing 10 sub-lines, with the offset between the sub-lines set to 10 µm.

[0021] Due to the adoption of the above technical solutions, the beneficial effects of this application are as follows:

[0022] The laser scribing method for carbon-based perovskite solar cells in this application uses offset stacked etching to achieve laser scribing etching of carbon back electrodes. Furthermore, the energy input of a single etching is lower than the melting threshold of the carbon back electrode material, avoiding the problem of carbon electrode melting and re-solidification forming a crater effect caused by a single high energy input. The two-batch stacked etching can effectively remove carbon electrodes, resulting in clean line stripping without residue or thermal damage. Attached Figure Description

[0023] Figure 1 This is an observation result diagram of the line drawn on P3 in Embodiment 1 of this application;

[0024] Figure 2 This is an observation result diagram of the line drawn on P3 in Embodiment 2 of this application;

[0025] Figure 3 A diagram showing the observation results of lines drawn for P1, P2 and P3 in Comparative Example 1 of this application;

[0026] Figure 4 The diagram shows the observation results of P1, P2 and P3 in Comparative Example 2 of this application. Detailed Implementation

[0027] Existing P3 scribing techniques, when directly applied using traditional laser processes for metal electrodes, produce a crater effect. This study suggests that this is primarily due to the excessively high single-shot energy input of the laser beam, which triggers the melting and resolidification of the carbon electrode, forming a crater-like protrusion. Therefore, theoretically, reducing the single-shot energy input of the laser beam to below the melting threshold of the carbon back electrode material can prevent the carbon electrode from melting and resolidifying, thus avoiding the crater effect.

[0028] However, this study found that reducing the single-shot energy input of the laser beam fails to effectively remove carbon material, resulting in carbon residue and hindering clean line removal. Furthermore, if a second laser beam with lower energy is applied to the same location, the accumulated energy from the previous beam will still cause a crater effect. In other words, even using a laser beam with an energy input below the melting threshold of the carbon back electrode material for multiple etches at the same location will still result in a crater effect if effective carbon removal is desired.

[0029] Based on the above research and understanding, this application creatively proposes a new laser scribing method for carbon-based perovskite solar cells, including P1 scribing, P2 scribing and P3 scribing; wherein, P3 scribing includes using a laser beam with energy input lower than the melting threshold of the carbon back electrode material to scribing the carbon back electrode in at least two batches, after the laser beam completes the first batch of scribing, the laser beam is shifted a certain distance along the scribing width direction to perform the second batch of scribing etching, the carbon back electrode is removed in the overlapping area of ​​the two batches of scribing, and the carbon material retained in the non-overlapping area still participates in carrier transport.

[0030] The core improvement of this application lies in the use of an offset overlapping etching method: after the first scribe is completed, the laser beam is offset downward by a certain distance for the second etching. The carbon electrode is effectively removed by utilizing the overlapping area of ​​the two scribes, while the carbon material retained in the non-overlapping area can still participate in carrier transport, thus avoiding the crater effect caused by a single high-energy input.

[0031] The physical mechanism of the offset overlay process is as follows: the energy input for both etching processes is below the melting threshold of the carbon material. A single etching process only causes partial peeling or loosening of the carbon material; during the second etching, the partially peeled carbon material is more easily removed. The offset setting allows the overlapping area to receive two energy inputs for complete removal, while the non-overlapping area receives only one energy input, allowing the carbon material to be retained.

[0032] In one implementation of this application, the P3 scribing uses a flat-top picosecond pulsed laser with an output power of 34 W, a pulse width of 144 ns, and a wavelength of 1064 nm; the P1 scribing includes etching the bottom electrode using a Gaussian picosecond pulsed laser with an output power of 4.4 W, a pulse width of 15-25 ns, and a wavelength of 1064 nm; and the P2 scribing includes etching the perovskite functional layer using a Gaussian picosecond pulsed laser with an output power of 3.3 W, a pulse width of 15-25 ns, and a wavelength of 1064 nm.

[0033] In determining the P3 scribing process parameters, this application fully considers the material properties of the carbon electrode and the laser action mechanism:

[0034] 1. Laser wavelength selection (1064 nm): Carbon materials have a high light absorption coefficient in the near-infrared band. At the same time, this band has a moderate penetration depth for the underlying perovskite material and TCO, which can effectively remove carbon electrodes while avoiding excessive damage to the underlying functional layer.

[0035] 2. Pulse width selection (144 ns): This pulse width is located at the junction of nanoseconds and picoseconds, balancing thermal and photomechanical effects. The 144 ns pulse width can create moderate thermal accumulation in carbon materials, causing them to expand and peel off rather than melt and re-solidify. Combined with offset overlay etching, this effectively solves the crater effect.

[0036] 3. Flat-top spot selection: Compared with Gaussian spots, flat-top spots have a more uniform energy distribution, which can avoid local overheating caused by excessively high energy in the center of the spot and residual problems caused by insufficient energy at the edge.

[0037] In one implementation of this application, the effects of laser parameters and overlay strategies on the scribing quality of carbon-based perovskite solar cells P1, P2, and P3 are systematically studied. The main conclusions and improvements are as follows:

[0038] 1. P1 scribing: By appropriately increasing the laser power and reducing the scanning speed, the ITO layer can be completely removed, avoiding leakage between sub-cells caused by residue. For example, using 20% ​​power and a scanning speed of 400 mm / s achieves ideal results, with clear line edges and no thermal damage.

[0039] 2. P2 scribing: For example, reducing the scan speed to 300 mm / s helps to fully remove the functional layer, significantly reduces residues, and ensures reliable conduction between ITO and the carbon electrode.

[0040] 3. P3 Innovative Etching Process: Addressing the etching challenges of thick-film carbon electrodes, the offset overlapping etching method proposed in this application offers the following advantages:

[0041] a. The carbon electrode is completely removed through the synergistic effect of two low-energy etching processes, avoiding heat accumulation and crater effect caused by a single high-energy input.

[0042] b. The actual electrical isolation area is the overlapping part of the two lines. The line width can be precisely adjusted by the offset. For example, if the line width is 250 µm and the offset is 75 µm, an isolation line width of 175 µm can be obtained. An offset of 150 µm corresponds to an isolation line width of 100 µm, thus minimizing the dead zone. That is, an offset between 75 and 150 µm can achieve an isolation line width of 175 to 100 µm.

[0043] c. The carbon material retained in the non-overlapping area can still participate in carrier collection without losing the effective power generation area; the edges are flat and there is no carbon particle adhesion, which helps to improve the module fill factor and long-term stability.

[0044] For example, in one implementation of this application, an offset of 150 µm is used to obtain a clean etched area with a linewidth of 100 µm and smooth edges without thermal damage. The offset overlay process of this application simultaneously achieves the two contradictory goals of "complete removal of carbon electrodes" and "effective suppression of cratering," whereas high removal rates are usually accompanied by high thermal damage.

[0045] It should be noted that the offset etching method proposed in this application is not only applicable to the ITO substrate, SnO2 electron transport layer, P3HT hole transport layer, and screen-printed carbon electrode system used in this application, but its core process idea lies in achieving "selective removal" of thick film materials through two offset etching processes. It is also applicable to other types of carbon-based perovskite solar cells, such as those using FTO substrates, different hole transport materials, and different carbon electrode fabrication processes. Those skilled in the art can achieve similar technical effects by adaptively adjusting the laser parameters and offset amount based on the specific material characteristics, according to the inspiration of this application.

[0046] In summary, the laser scribing optimization process provided in this application effectively solves key process challenges in the large-scale fabrication of carbon-based perovskite solar cells, such as P1 residue, incomplete P2 removal, and incomplete P3 etching and thermal damage. In particular, the P3 offset overlay etching method achieves controllable dead zones and improved edge quality while ensuring isolation reliability, which is of great significance for promoting the industrial-scale expansion of carbon-based perovskite photovoltaic technology. Compared with existing technologies, this application has the following beneficial effects:

[0047] 1. Etching integrity: Achieve complete removal of carbon electrodes with no residue, eliminating the risk of short circuits.

[0048] 2. Thermal damage control: No crater, smooth edges without thermal damage, avoiding interface contact and interface undulations from affecting subsequent packaging processes.

[0049] 3. Dead zone minimization: The linewidth can be precisely adjusted to 100 µm, which allows for precise control of the dead zone area and maximizes the effective power generation area.

[0050] 4. Simplified process: No new materials or equipment are required; only laser process parameters and overlay strategies are optimized, resulting in low cost and easy promotion.

[0051] 5. Industrial applicability: It provides a complete and mass-producible P3 scribing solution, filling the gap in dedicated P3 scribing processes for carbon-based perovskite solar cells.

[0052] In one implementation of this application, the laser scribing method for carbon-based perovskite solar cells specifically includes the following steps:

[0053] S1: Etching line P1 on the ITO glass surface

[0054] A 600 mm × 600 mm ITO conductive glass was fixed on the XY axis system of a laser processing platform. After focal length calibration, a Gaussian spot picosecond laser was used to optimize the scribing process parameters. By adjusting the laser power, pulse frequency, pulse width, and scanning speed, the morphology of the etched lines and the inter-line resistance were evaluated to determine the optimal process window for achieving complete removal of the ITO layer without damage to the bottom glass.

[0055] S2: P2 line etching on the surface of the functional layer

[0056] After P1 etching, ultrasonic cleaning, and drying, the ITO substrate underwent sequential UVO treatment, SnO2 layer slot coating (annealing at 160℃ for 30 min), perovskite layer slot coating (vacuum-assisted crystallization treatment: 1 Pa low pressure held for 10 s, followed by annealing at 160℃ for 30 min), and P3HT layer slot coating (annealing at 120℃ for 10 min). In the slot coating process, the gap between the coating head and the substrate was fixed at 80 µm, and the platform speed was 15 mm / s. P2 scribing used the same laser system as P1, controlling the etching width by stacking 10 sub-lines, with an offset of 10 µm between sub-lines. The laser parameters were adjusted to optimize the P2 line morphology, ensuring complete removal of the functional layer and no damage to the exposed ITO layer.

[0057] S3: P3 line etching on the carbon electrode surface

[0058] The substrate with P2 scribing completed was screen-printed to deposit carbon electrodes (screen size: 100 mesh stainless steel mesh), and annealed at 120℃ for 30 min to obtain a carbon film with a thickness of approximately 30 µm. P3 scribing was performed using a flat-top picosecond laser, and the etching morphology was optimized by adjusting the power, scanning speed, and overlay strategy. The core improvement of this application lies in the use of an offset overlay etching method: after the first scribing is completed, the laser beam is offset downwards by a certain distance for a second etching. The overlapping area of ​​the two scribings is used to effectively remove the carbon electrode, while the carbon material retained in the non-overlapping area can still participate in carrier transport, while avoiding the crater effect caused by a single high-energy input.

[0059] The present application will be further described in detail below through specific embodiments. The following embodiments are only for further illustration of the present application and should not be construed as limiting the present application.

[0060] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0061] Example 1

[0062] S1: Etch P1 lines on the ITO glass surface

[0063] Optimized P1 scribing parameters: power 4.4 W, frequency 50 kHz, pulse width 20 ns, wavelength 1064 nm, scan speed 400 mm / s. Testing showed that the P1 line was open-circuited at both ends. Microscopic observation revealed a line width of approximately 30 µm, neat edges, complete removal of the ITO layer, and no heat-affected zone.

[0064] S2: P2 etching lines on the surface of the functional layer

[0065] The P2 scribing parameters were optimized: power 3.3 W, frequency 20 kHz, pulse width 20 ns, wavelength 1064 nm, scan speed 300 mm / s, and 10 lines superimposed. Microscopic observation showed a line width of approximately 130 µm, with neat edges. Only a small amount of functional layer remained in the superimposed line area, which did not affect the effective contact between the ITO and the carbon electrode.

[0066] S3: Etching P3 lines on the carbon electrode surface

[0067] The P3 scribing employed an offset overlay process: the initial scribing parameters were 34 W power, 50 kHz frequency, 144 ns pulse width, 1064 nm wavelength, and 400 mm / s scan speed. Microscopic examination revealed that the width of the initial scribing was approximately 250 µm, and the second scribing was offset downwards by 75 µm. Microscopic observation showed that the carbon electrode was completely removed in the overlapping area of ​​the two lines, forming an effective isolation linewidth of approximately 175 µm; the non-overlapping edges showed no cratering phenomenon and had a smooth morphology. Figure 1 As shown.

[0068] Figure 1 In the figure, a shows the overall morphology of the P3 scribing, which uses two overlapping etchings with an offset of 75 µm. The carbon electrode in the overlapping area of ​​the two lines (with a central bandwidth of about 175 µm) is completely removed, forming an effective isolation zone; the non-overlapping edges are flat and there is no crater phenomenon; b is a magnified view of a part of the P3 scribing, which clearly shows that its etching edges are clear and sharp, with no signs of thermal damage and no carbon particles remaining.

[0069] Example 2

[0070] The parameters S1 and S2 are the same as in Example 1.

[0071] S3: Etching P3 lines on the carbon electrode surface

[0072] The P3 scribing process uses an offset overlay process. The initial scribing parameters are the same as in Example 1, but the offset is increased to 150 µm. The rest are the same as in Example 1.

[0073] Microscopic observation revealed that the overlapping area formed a clean etched zone with a linewidth of approximately 100 µm, with smooth edges, no crater-like edges, and no residual carbon particles. Figure 2As shown, by adjusting the offset, the etching linewidth can be effectively controlled, minimizing the dead area while ensuring isolation reliability.

[0074] Figure 2 In the figure, a shows the overall morphology of the P3 scribing: two overlapping etching processes with an offset of 150 µm were used, and the overlapping area formed a clean etching zone with a line width of about 100 µm, which achieved precise control of the isolation line width; the non-overlapping edges are flat and smooth, without craters or carbon particle adhesion; b is a magnified view of a part of the P3 scribing, which clearly shows that its etching interface is clear and the edge quality is excellent, minimizing the dead area area while ensuring the reliability of isolation.

[0075] Comparative Example 1

[0076] S1: Etching line P1 on the ITO glass surface

[0077] Optimized P1 scribing parameters: power 4.4 W, frequency 50 kHz, pulse width 20 ns, wavelength 1064 nm, scan speed 400 mm / s. Testing showed that the P1 line was open-circuited at both ends. Microscopic observation revealed a line width of approximately 30 µm, clean edges, complete removal of the ITO layer, and no heat-affected zone. Figure 3 As shown in Figures a and b, Figure b is a magnified view of a portion of the image.

[0078] S2: P2 line etching on the surface of the functional layer

[0079] The P2 scribing parameters were optimized: power 3.3 W, frequency 20 kHz, pulse width 20 ns, wavelength 1064 nm, scan speed 300 mm / s, and 10 lines superimposed. Microscopic observation showed a line width of approximately 130 µm, with neat edges. Only a small amount of functional layer remained in the superimposed area, not affecting the effective contact between the ITO and the carbon electrode. Figure 3 As shown in Figures c and d, Figure d is a magnified view of a portion of the image.

[0080] S3: Etching P3 lines on the carbon electrode surface

[0081] The P3 etching process employed a double-layer etching technique at the same location, with a power of 34 W, a frequency of 50 kHz, a pulse width of 144 ns, a wavelength of 1064 nm, and a scan speed of 400 mm / s. The same trajectory was etched twice. Microscopic observation showed a linewidth of approximately 250 µm and a significant reduction in residual carbon particles. However, crater-like protrusions were still visible at the etched edges, indicating that the thermal effect issue was not completely resolved. Figure 3 The figures e and f are shown.

[0082] Figure 3In the diagram, Figures a and b show the morphology of the P1 etched lines. The P1 etched lines are approximately 30 µm wide, with a smooth etching interface, undamaged bottom glass, complete removal of the ITO layer, no residue or heat-affected zone, and an open circuit in the inter-line resistance. Figures c and d show the morphology of the P2 etched lines. The P2 etched lines are approximately 130 µm wide, with neat edges. Only a small amount of functional layer fragments remain in the overlay area, resulting in improved electrical contact reliability and no impact on the conduction between the ITO and carbon electrodes. Figures e and f show the morphology of the P3 etched lines. Figure f is a magnified view of a portion of the etched lines. It shows that a secondary overlay process was used at the same location, resulting in a line width of approximately 250 µm. Carbon particles were largely removed, but a significant crater-like bulge is visible at the etching edge, indicating that the thermal effect issue has not been completely resolved.

[0083] Comparative Example 2

[0084] The traditional single-etching process is used, as detailed below:

[0085] S1: Etching line P1 on the ITO glass surface

[0086] Power 3.3 W, frequency 50 kHz, pulse width 20 ns, wavelength 1064 nm, scan speed 500 mm / s. After etching, the resistance across the P1 line measured with a multimeter was 150 Ω, indicating a short circuit between the sub-cells. Microscopic observation showed a line width of approximately 30 µm with clear edges, but some areas still showed incomplete removal of ITO residue, such as... Figure 4 As shown in Figures a and b, Figure b is a magnified view of a portion of the image.

[0087] S2: P2 line etching on the surface of the functional layer

[0088] Power 3.3 W, frequency 20 kHz, pulse width 20 ns, wavelength 1064 nm, scan speed 500 mm / s, 10-line superposition. Microscopic observation showed a line width of approximately 100 µm, with jagged edges, and obvious functional layer residues in the superimposed line areas, such as... Figure 4 As shown in Figures c and d, with Figure d being a magnified view of a portion, residual functional layers will affect the electrical contact between ITO and the carbon electrode.

[0089] S3: P3 line etching on the carbon electrode surface

[0090] Power 34 W, frequency 50 kHz, pulse width 144 ns, wavelength 1064 nm, scan speed 400 mm / s, single-pass etching. Microscopic observation shows that due to the large carbon electrode particles and thick film, significant carbon particle residue remains after etching, resulting in incomplete isolation of the sub-cells and a high risk of short circuits. Figure 4 As shown in Figures e and f, Figure f is a magnified view of a portion of the image.

[0091] Figure 4In the diagram, Figures a and b are magnified views of the P1 etched section: the line width is approximately 30 µm with clear edges, but there are scattered ITO residues within the etched area, resulting in incomplete isolation between sub-cells. Multimeter testing shows an inter-line resistance of only 150 Ω. Figures c and d show the P2 etched section: the line width is approximately 100 µm with irregular serrated edges. Obvious functional layer (perovskite / P3HT) residues are visible in the middle of the overlapping area, which will hinder effective contact between the subsequent carbon electrode and the ITO bottom electrode. The residue morphology is clearly visible. Figures e and f show the P3 etched section: a single etching process was used, resulting in irregular line widths and severe carbon particle residues within the etched area. Effective isolation between sub-cells was not achieved. The dense distribution of residual carbon particles poses an extremely high risk of short circuits.

[0092] Based on Example 1, this application further tested the output power, pulse width, and wavelength of the P1 scribing, P2 scribing, and P3 scribing. The results showed that the P1 scribing, using an output power of 3-5 W, a pulse width of 15-25 ns, and a wavelength of 1000-1200 nm; the P2 scribing, using an output power of 3-5 W, a pulse width of 15-25 ns, and a wavelength of 1000-1200 nm; and the P3 scribing, using an output power of 20-50 W, a pulse width of 120-160 ns, and a wavelength of 1000-1200 nm, could effectively remove each layer. Moreover, the carbon electrode lines were cleanly peeled off, without residue, without thermal damage, and without crater effect.

[0093] The above description, in conjunction with specific embodiments, provides a further detailed explanation of this application and should not be construed as limiting the specific implementation of this application to these descriptions. Those skilled in the art to which this application pertains can make several simple deductions or substitutions without departing from the concept of this application.

Claims

1. A laser scribing method for carbon-based perovskite solar cells, characterized in that: This includes the lines drawn on P1, P2, and P3. The P3 scribing process includes scribing the carbon back electrode with a laser beam whose energy input is lower than the melting threshold of the carbon back electrode material in at least two batches. After the laser beam completes the first scribing, the laser beam is shifted a certain distance along the scribing width direction to perform the second scribing etching. The carbon back electrode is removed in the overlapping area of ​​the two scribings, while the carbon material retained in the non-overlapping area still participates in carrier transport.

2. The laser scribing method according to claim 1, characterized in that: The P3 line drawing uses a flat-top picosecond pulsed laser with an output power of 20-50W, a pulse width of 120-160 ns, and a wavelength of 1000-1200nm.

3. The laser scribing method according to claim 1, characterized in that: The P1 etch involves etching the bottom electrode using a Gaussian spot picosecond pulsed laser with an output power of 3-5 W, a pulse width of 15-25 ns, and a wavelength of 1000-1200 nm.

4. The laser scribing method according to claim 1, characterized in that: The P2 etching process involves using a Gaussian spot picosecond pulsed laser with an output power of 3-5 W, a pulse width of 15-25 ns, and a wavelength of 1000-1200 nm to etch the perovskite functional layer.

5. The laser scribing method according to claim 1, characterized in that: The carbon-based perovskite solar cell comprises a bottom electrode, a perovskite functional layer, and a carbon back electrode stacked in sequence. The bottom electrode is an indium tin oxide thin film, and the perovskite functional layer comprises an electron transport layer, a perovskite light-absorbing layer, and a hole transport layer.

6. The laser scribing method according to claim 5, characterized in that: The thickness of the indium tin oxide film is 100-200 nm.

7. The laser scribing method according to claim 5, characterized in that: The thickness of the carbon back electrode is 20-40 µm.

8. The laser scribing method according to any one of claims 1-7, characterized in that: The P1 scribing process also includes etching the bottom electrode, followed by ultrasonic cleaning and drying in preparation for the subsequent P2 scribing.

9. The laser scribing method according to any one of claims 1-7, characterized in that: The P2 scribing method involves using 10 sub-lines to control the etching width, with the offset between sub-lines set to 10 µm.

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