A preparation method of an organic solar cell module based on a P1 groove filling technology

Abstract

This invention discloses a method for fabricating an organic solar cell module based on P1 trench filling technology, relating to the field of organic solar cells. The method includes: performing P1 laser etching on a transparent conductive substrate to form P1 trenches; coating the substrate with UV insulating adhesive to fill the P1 trenches; employing a selective ultraviolet curing process to only cure the insulating adhesive inside the P1 trenches, creating a difference in physicochemical properties between the solid and liquid states; selectively removing the uncured liquid insulating adhesive outside the P1 trenches using a developing cleaning solution, retaining the cured adhesive inside the trenches to form a stepless, flat interface; and sequentially fabricating other functional layers of the organic solar cell on the flat interface. This invention eliminates physical steps by filling the P1 trenches, avoiding voids, stress concentrations, and crystallization defects in subsequent thin film deposition, significantly improving the photoelectric conversion efficiency and long-term stability of large-area organic solar cell modules, and exhibiting high yield and good industrial compatibility.

Description

Technical Field

[0001] This invention relates to the field of organic solar cells, specifically to a method for preparing an organic solar cell module based on P1 trench filling technology. Background Technology

[0002] Currently, organic modules typically employ laser scribing to achieve series integration of sub-cells, with P1 scribing aimed at patterning the bottom electrode (such as ITO, FTO, etc.). However, this process generates trenches with a width of micrometers and a depth of hundreds of nanometers on the substrate surface, forming significant physical steps. These steps have a severe negative impact on subsequent thin films deposited using solution methods (such as spin coating, blade coating, printing, etc.), especially organic light-absorbing layers: on the one hand, it causes uneven flow of the organic precursor solution at the trench edges, resulting in inconsistent film thickness, voids, or incomplete coverage, leading to fracture phenomena; on the other hand, during organic crystallization, the steps easily become stress concentration points and nucleation sites, inducing lattice defects and reducing crystal quality. These defects ultimately manifest as increased series resistance, aggravated leakage current, decreased fill factor and open-circuit voltage in the module, resulting in overall performance and yield far lower than small-area cells.

[0003] Therefore, developing a method to effectively smooth out P1 scribing grooves and optimize the thin film growth interface is crucial for achieving high-performance, high-yield organic solar modules. Summary of the Invention

[0004] The purpose of this invention is to provide a method for fabricating organic solar cell modules based on P1 trench filling technology. The method employs a large-area organic tandem module using P1 laser scribing trench filling technology. By using a UV insulating adhesive of a specific viscosity to precisely fill and planarize the deep P1 trenches, the step effect of subsequent thin film deposition is effectively eliminated, contaminant residue is avoided, and the open-circuit voltage, fill factor, and long-term stability of the module are significantly improved, thereby solving the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing an organic solar cell module based on P1 trench filling technology, comprising the following steps:

[0006] S1: Provide a transparent conductive substrate, and use a laser to etch and scribble lines on the transparent conductive substrate to form independent strip conductive electrodes and P1 trenches. The P1 trenches provide a defined micro-nano-level physical containment space for subsequent filling of insulating materials.

[0007] S2: Apply UV insulating adhesive to the transparent conductive substrate, and use capillary action and solution leveling properties to fill the space of the P1 trench with the UV insulating adhesive.

[0008] S3: Selective UV curing process is adopted. Based on the spatial distribution of P1 trenches, only the UV insulating adhesive inside the P1 trenches is photocured, while the UV insulating adhesive outside the P1 trenches remains liquid. This creates a difference in the physicochemical properties of solid and liquid in the same coating.

[0009] S4: Clean the transparent conductive substrate with a developing cleaning solution. Utilize the differences in the physicochemical properties constructed above to selectively remove the uncured liquid UV insulating adhesive outside the P1 trench, while retaining the cured adhesive inside the trench. This makes the cured UV insulating adhesive inside the P1 trench flush with the surrounding exposed substrate surface, forming a stepless, flat interface.

[0010] S5: Relying on the above-mentioned stepless flat interface to eliminate the stress concentration points of crystallization, other functional layers of organic solar cells are sequentially deposited and prepared on the interface.

[0011] Preferably, in step S1, the width of the P1 trench is 20-80 μm and the depth is 50-1000 nm. This size range is configured to match the viscosity of the UV insulating adhesive in step S2 to ensure complete capillary penetration of the adhesive. The laser used is an infrared nanosecond pulse laser or a picosecond pulse laser with an output wavelength of 1064 nm.

[0012] Preferably, in step S2, the UV insulating adhesive is applied using a scraping method or a slot coating method, and the wet film thickness is controlled at 1-3 μm; the viscosity of the UV insulating adhesive is set to 15-45 mPa·s, and the UV insulating adhesive is configured to have a photocuring volume shrinkage rate of less than 3% to prevent volume collapse after photocrosslinking in step S3, thereby destroying the stepless flat interface expected in step S4.

[0013] Preferably, the UV insulating adhesive is selected from any one or more combinations of acrylate UV adhesive, epoxy resin UV adhesive, polyurethane UV adhesive, or organic-inorganic hybrid UV transparent insulating adhesive. The material system is specially equipped with a photoinitiator that precisely matches the wavelength of the selective ultraviolet exposure light source described in step S3, so as to ensure that the adhesive triggers a rapid crosslinking reaction only under a specific ultraviolet band.

[0014] Preferably, a reference mark point is etched at the edge of the substrate while etching the P1 trench; in step S3, the selective ultraviolet curing process specifically includes:

[0015] The interior of the P1 trench was precisely irradiated and cured using a picosecond pulsed ultraviolet laser with a wavelength of 355nm.

[0016] The precise irradiation curing system, combined with a high-precision coaxial organic solar cell D-vision recognition and tracking system, automatically calculates and compensates for the current substrate position deviation by capturing the reference Mark point generated in step S1. This guides a 355nm ultraviolet laser beam to precisely scan and write along the center line of the P1 trench, with the scanning offset controlled within ±2μm, limiting the curing crosslinking reaction to occur only within the physical boundary of the P1 trench.

[0017] As a preferred embodiment, in step S3, another alternative implementation of the selective ultraviolet curing process is as follows:

[0018] A mask with a light-transmitting slit array is provided, and a visual positioning system is used to make the light-transmitting slit array correspond one-to-one with the P1 groove array formed in step S1 in spatial position;

[0019] A high-power ultraviolet LED surface light source is used to globally expose the substrate through the mask. The light-blocking area of ​​the mask is used to block ultraviolet light from reaching the outside of the P1 trench, so that ultraviolet light can only pass through the slit to irradiate the P1 trench area, thereby achieving one-time local curing of the UV insulating adhesive in the trench.

[0020] Preferably, in step S4, the developing and cleaning solution is a mixture of isopropanol and propylene glycol methyl ether acetate (PGMEA) in a volume ratio of 1:1 to 3:1. This mixture is configured to have a high efficiency in dissolving uncured liquid UV insulating adhesive, while maintaining chemical inertness to the cross-linked and cured UV insulating adhesive in step S3, thus preventing the cured adhesive from swelling and deforming.

[0021] Preferably, the cleaning process in step S4 specifically includes: cleaning with low-pressure spray combined with megasonic waves at a frequency of 1MHz, utilizing the cavitation effect of megasonic waves to accelerate the peeling of liquid colloids in conjunction with the developing cleaning solution, and the physical impact force of the low-pressure spray is set to be less than the adhesion force between the cured UV insulating adhesive and the inner wall of the P1 trench, with a single cleaning time of 15-30 seconds, followed by rinsing with isopropyl alcohol and drying with a nitrogen air knife after cleaning.

[0022] Preferably, in step S1, both before and after laser etching of P1, an automated pre-cleaning process for the transparent conductive substrate is included. The pre-cleaning process includes, in sequence: brush pre-washing, dual-frequency ultrasonic cleaning, two-stage ultrapure water countercurrent rinsing, air knife drying, hot air drying, and UV ozone activation. The UV ozone activation process is used to improve the hydrophilicity of the substrate surface, thereby promoting the uniform, pore-free spreading of the UV insulating adhesive in the P1 trench in step S2.

[0023] Preferably, the organic solar cell described in step S5 adopts a nip formal structure or a pin inverse structure; the conductive layer material of the transparent conductive substrate described in step S1 includes any one or a combination of at least two of ITO, FTO, AZO, ATO, IGO or BZO.

[0024] In summary, the beneficial effects of this invention are:

[0025] 1. Eliminating the step effect at its source and reshaping the ideal interface: Breaking through the inertia of traditional laser scribing followed by direct thin film deposition, this method cleverly utilizes a micro-nano fabrication approach of "full coating + selective curing + development and residue removal" to perfectly fill the P1 trench. This provides a truly "step-free and smooth interface" for the subsequent solution coating of the organic light-absorbing layer, completely eliminating pores and dead corners caused by uneven solution flow at the trench edges.

[0026] 2. High-precision targeted curing, completely avoiding interference from impurities and residual adhesive: The combination of organic solar cell D-vision coaxial tracking and 355nm picosecond ultraviolet laser (or precise mask alignment) ensures that the crosslinking reaction is strictly confined within a physical boundary of tens of micrometers. This avoids the "residual adhesive protrusion outside the trench" phenomenon that is very easy to occur in conventional coating and filling processes, ensuring the conductivity of the bottom electrode.

[0027] Customized materials and developing processes overcome the challenges of volume shrinkage and swelling: A UV adhesive with a low shrinkage rate (<3%) eliminates the secondary "micro-valleys" formed by the collapse of the cured adhesive. More importantly, an innovative development solution using a specific ratio of IPA and PGMEA achieves highly efficient peeling of the uncured adhesive while perfectly avoiding the swelling and deformation of the cured adhesive, ensuring physical flatness at the microscopic level.

[0028] 3. Significantly improves the photoelectric performance and long-term yield of large-area modules: The repaired and smoothed interface effectively eliminates stress concentration points and abnormal nucleation sites during the film formation process, greatly improving the crystal integrity and density of the organic thin film. Macroscopically, this is directly manifested in a significant reduction in device series resistance and effective suppression of leakage current, thereby greatly improving the open-circuit voltage, fill factor, and overall long-term environmental stability of large-area organic solar cell modules.

[0029] 4. High compatibility with existing production lines: Whether it is the laser direct writing solution or the mask global exposure solution, it can be perfectly integrated with existing automated cleaning and coating equipment without the need to develop overly demanding special equipment, which greatly promotes the process of large-scale industrialization of organic solar modules. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the P1 trench filling and curing process in the method for preparing an organic solar cell module based on P1 trench filling technology according to the present invention.

[0032] Figure 2 This is a schematic diagram illustrating the problems caused by P1 trenches in the prior art in the method for preparing an organic solar cell module based on P1 trench filling technology of the present invention.

[0033] Figure 3 This is a comparison diagram of the thin film coverage effect between the organic solar cell module preparation method based on P1 trench filling technology of the present invention and the prior art.

[0034] Figure 4 This is a characteristic curve diagram of the organic solar cell module prepared by the present invention and the prior art in the method for preparing an organic solar cell module based on P1 trench filling technology of the present invention.

[0035] Figure 5 This is a maximum power point tracking stability test diagram comparing the organic solar cell module prepared by this invention with existing technologies in the method for preparing an organic solar cell module based on P1 trench filling technology. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. These drawings are simplified schematic diagrams, which are only used to illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0037] To facilitate understanding of the present invention, a more complete description of the invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the invention. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the invention will be more thorough and complete.

[0038] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0039] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features for a similar purpose, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of at least two elements or the interaction relationship of at least two elements, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] The large-area organic solar module mentioned in this invention typically employs a series structure. Its typical fabrication process includes steps such as transparent conductive bottom electrode deposition, P1 scribing, bottom electrode modification layer coating (e.g., electron transport layer or hole transport layer), organic light-absorbing layer coating, top electrode modification layer coating, P2 / P3 scribing, and top electrode deposition. (See also...) Figure 2 In the existing technology, the concave film at the P1 groove is prone to breakage. The core of this invention lies in the groove filling and surface repair process after the P1 line is drawn.

[0042] Please see Figure 1 Embodiment 1 of the present invention: A method for preparing an organic solar cell module based on P1 trench filling technology, comprising the following steps:

[0043] Step 1: Preparation of transparent conductive substrate and P1 etching;

[0044] Substrate pre-cleaning: A glass substrate with a 150 nm thick ITO (indium doped tin oxide) conductive layer deposited on it was selected.

[0045] The substrate was placed in an automated cleaning machine for multi-stage cleaning: first, it was fed at a speed of 2.0 m / min with a brush rotation speed of 100 rpm, and pre-washed with 0.3 MPa pure water; then, it underwent dual-frequency ultrasonic cleaning at 40 kHz / 68 kHz (power density 0.5 W / cm², 5 minutes); followed by two stages of 18.2 MΩ·cm ultrapure water countercurrent rinsing (spray pressure 0.25 MPa); after pure water ultrasonic fine cleaning, the surface moisture was dried using an air knife at 0.45 MPa and an angle of 20°, and then it entered a 55℃ hot air drying zone; finally, it underwent 15 minutes of 185 nm + 254 nm dual-band UV ozone activation to enhance the hydrophilicity and surface energy of the ITO surface.

[0046] P1 laser marking: Reference Figure 1 Sub-figure a shows the etching of the ITO conductive layer using a 1064 nm infrared nanosecond pulsed laser at a frequency of 100 kHz and a power of 20 W, forming a series of parallel, insulated P1 trenches. The scribing width was set to 40 μm and the depth to approximately 150 nm, just enough to penetrate the ITO layer without damaging the glass substrate. Simultaneously, the laser etched reference crosshair marks in the non-working area of ​​the substrate. After scribing, the substrate was cleaned again using the aforementioned automated cleaning equipment to remove spatter and dust contamination generated during laser processing.

[0047] Step 2: Apply UV insulating adhesive to the entire surface, refer to... Figure 1 Subgraph b;

[0048] A cationic, UV-curable transparent insulating adhesive was selected, consisting of a modified alicyclic epoxy resin and an oxetane monomer, with the addition of a photoinitiator sensitive to a wavelength of 355 nm (such as triarylsulfonium salt). The room temperature viscosity of this UV adhesive formulation was adjusted to 30 mPa·s, and the cured volume shrinkage rate was 2.1%.

[0049] The UV insulating adhesive was uniformly applied to the cleaned substrate surface using a slot-die coating apparatus at a speed of 1.5 m / min. The wet film thickness was controlled to approximately 1.5 μm by adjusting the pump flow rate and slot gap. After coating, the substrate was allowed to stand at room temperature for 8 minutes to allow the low-viscosity UV adhesive to fully flow into and fill the 40 μm wide and 150 nm deep P1 trenches under capillary action and gravity.

[0050] Step 3: Selective and precise curing based on the D-position of organic solar cells, refer to... Figure 1 Subgraphs c and d;

[0051] The substrate coated with uncured UV adhesive is transferred to the laser curing station, which is equipped with a 355 nm picosecond pulsed ultraviolet laser and a coaxial organic solar cell D vision alignment system.

[0052] The organic solar cell D system first captures the reference crosshair mark at the edge of the substrate. An image recognition algorithm calculates the current X / Y axis translational deviation and rotational angle deviation (θ angle) of the substrate, and feeds this information back to the galvanometer control system for real-time compensation. Subsequently, a 355 nm ultraviolet laser beam with a 5 μm spot diameter precisely scans and writes along the centerline of each P1 trench. By optimizing the laser energy and scanning speed, the UV adhesive inside the trench instantly absorbs ultraviolet light and undergoes cationic cross-linking and curing, while the UV adhesive on the surface of the outer area of ​​the trench remains liquid because it is not exposed to light. Actual measurements show that the cured area is strictly controlled within ±2 μm of the trench edge.

[0053] Step 4: Low-voltage megasonic imaging and cleaning, refer to... Figure 1 Subgraph e;

[0054] Prepare the developing and cleaning solution by mixing isopropanol (IPA) and propylene glycol methyl ether acetate (PGMEA) at a volume ratio of 2:1.

[0055] The substrate was fed into a developing and cleaning machine, where a low-pressure spray of 0.05 MPa combined with 1 MHz megasonic waves was used to clean the substrate surface for 20 seconds. This ratio of mixed developer solution rapidly dissolved and removed a large area of ​​uncured liquid UV adhesive outside the trenches; simultaneously, due to the rapid evaporation of PGMEA and its low compatibility with the cured epoxy resin network, the cross-linked UV adhesive inside the trenches did not swell.

[0056] After development, the substrate was rinsed with pure isopropanol and finally dried using a nitrogen air knife. Atomic force microscopy (AFM) or profilometry showed that the cured colloid in the P1 trench was flush with the surface of the surrounding ITO conductive layer after cleaning, with a step height difference of less than 10 nm, successfully constructing a smooth interface without physical defects.

[0057] Step 5: Subsequent deposition of the organic module;

[0058] On this smooth interface, an electron transport layer (such as ZnO nanoparticle solution), an organic active layer (such as PM6:Y6 system), and a hole transport layer (such as PEDOT:PSS) are deposited sequentially using a solution coating method. Finally, metallic silver (Ag) is evaporated as the top electrode, and combined with the conventional P2 / P3 scribing process, the fabrication of a large-area organic tandem module is completed.

[0059] Example 2: P1 trench filling based on photomask exposure technology, the only difference from Example 1 is the curing method in the third step, as follows:

[0060] After the UV insulating adhesive is applied to the entire surface of the substrate in the second step and allowed to stand, the substrate is transferred to the surface light source exposure station. A high-precision quartz glass mask is provided, on which a transparent slit array is fabricated. The slit width is 40 μm, and the spacing is completely consistent with the spacing of the P1 trenches on the substrate. Using an organic solar cell D-vision alignment system, the transparent slit array of the mask is aligned with the P1 trenches on the bottom of the substrate with high precision, achieving an alignment accuracy of ±2 μm.

[0061] Subsequently, a high-power 365 nm ultraviolet LED surface light source (light intensity approximately 1000 mW / cm²) located above the mask was turned on, and the substrate was globally exposed for 3 seconds. Due to the mask's obstruction, the ultraviolet light only penetrated the slits to illuminate the UV adhesive inside the P1 trench, initiating its localized photocrosslinking and curing. The UV adhesive in the non-trench areas was shielded and remained in a liquid state.

[0062] The subsequent fourth step of development and cleaning, and the fifth step of device fabrication are the same as in Example 1. This example is particularly suitable for high-speed mass production lines of roll-to-roll (R2R) or large-area sheet-to-sheet (S2S).

[0063] Comparative Example 1: Conventional Unfilled Process

[0064] To verify the technical effect of the present invention, Comparative Example 1 was set up.

[0065] Comparative Example 1 also uses a glass substrate with 150 nm ITO for P1 laser scribing (groove width 40 μm, depth 150 nm), but omits the second, third and fourth steps, i.e. the UV adhesive filling and cleaning process is not performed. After cleaning, step S5 is performed directly on the substrate with 150 nm physical steps, and electron transport layer, organic active layer, etc. are coated in sequence.

[0066] Performance comparison test and results analysis;

[0067] Organic solar modules with the same effective area, for example 50 cm², and consisting of 10 sub-cells connected in series, prepared in Examples 1, 2, and 1, were placed under a standard solar simulator (AM 1.5G, 100 mW / cm²) for JV performance testing. The test results are shown in the table below:

[0068]

[0069] refer to Figure 4 and Figure 5 Orange represents Example 1, and blue represents Comparative Example 1. The test data shows that Comparative Example 1 has a 150 nm deep P1 trench. Figure 3 The left side represents the experimental group, and the right side represents the example group. The organic active layer subsequently coated using the solution method is prone to uneven thickness or pinholes at the step points, indicated by red circles, leading to severe leakage current and stress defects. Its fill factor (FF) is only 52.3%, and the module yield is extremely low.

[0070] In contrast, Examples 1 and 2, which employ the technical solutions of this invention, have successfully filled the P1 trench and achieved nanoscale smoothness of the interface (step height difference <15 nm), completely eliminating leakage and crystallization defects caused by physical steps. The photoelectric conversion efficiency (PCE) has been significantly increased from 14.5% to about 18.5%, while effectively preventing short circuits caused by poor step coverage. This demonstrates extremely high industrial application value and significant progress.

[0071] refer to Figure 5 The long-term stability of the monitoring device under LED illumination was measured. The blue Comparative Example 1 module degraded to 51% of its initial efficiency (14.5%) after 500 hours; while the orange Example 1 module maintained 90% of its initial efficiency (18.5%) after 700 hours, showing slower efficiency degradation and better stability.

[0072] Example 3: Application in Flexible Organic Solar Modules

[0073] This embodiment aims to demonstrate the application of the present invention in flexible organic solar modules. When the flexible substrate is bent, stress concentration easily occurs at physical steps such as the P1 groove, leading to film layer breakage. The leveling technology of the present invention significantly improves this situation. The specific steps are as follows:

[0074] Substrate preparation and P1 etching: A 125 μm thick optical-grade PET flexible substrate was selected, with a 100 nm thick IZO (indium zinc oxide) transparent conductive layer deposited on its surface. P1 lines were etched using a 1064 nm picosecond laser, with a trench width of 30 μm and a depth of 100 nm.

[0075] Specific UV adhesive coating: Considering the bending requirements of the flexible substrate, this embodiment selects a polyurethane UV adhesive with excellent elasticity and elongation at break. Its room temperature viscosity is adjusted to 45 mPa·s, and the volume shrinkage rate after UV curing is strictly controlled at 2.5%. The entire surface of the PET substrate is coated using the slot coating method, with a wet film thickness of approximately 2 μm.

[0076] Selective precision curing: Using the same coaxial organic solar cell D vision system as in Example 1, along with a 355 nm ultraviolet laser, precise direct writing curing is performed along the center line of the P1 trench on the flexible substrate.

[0077] Development and Cleaning: A megasonic low-pressure cleaning process was performed using a 1:1 volume ratio of isopropanol to PGMEA developer to thoroughly remove uncured colloids. After development, the P1 grooves were perfectly filled with elastic polyurethane curing adhesive.

[0078] Subsequent device fabrication: An electron transport layer, a flexible organic active layer, and a top electrode were sequentially coated on a flat interface using a roll-to-roll (R2R) process to complete the fabrication of the flexible module. After undergoing 1000 bending tests (radius of curvature 5 mm), no cracks were observed in the P1 filled area of ​​the flexible module.

[0079] Example 4: This example demonstrates the adaptability of the present invention for thicker bottom electrodes (forming deep trenches) and scenarios requiring high-temperature resistance in subsequent processes. The specific steps are as follows:

[0080] Substrate preparation and P1 etching: A glass substrate with a 500 nm thick FTO (fluorine-doped tin oxide) conductive layer was selected. A P1 trench with a width of 60 μm and a depth of 500 nm was formed using laser scribing.

[0081] Specific UV adhesive coating: To ensure the adhesive can fully penetrate the 500 nm deep trench and meet the annealing temperatures that may be required for subsequent inorganic transport layers such as ZnO, an organic-inorganic hybrid UV transparent insulating adhesive (such as a system containing methylphenylsiloxane) is selected. It has extremely low viscosity, only 15 mPa·s, and a volume shrinkage rate of approximately 1.8%.

[0082] Selective and precise curing: Using the same quartz mask as in Example 2 and a high-power ultraviolet LED surface light source, a 5-second global alignment exposure is performed to achieve deep curing of the hybrid UV adhesive in the trench.

[0083] Developing and cleaning: For this low-viscosity hybrid system, the developer was adjusted to a mixture of isopropanol and PGMEA at a volume ratio of 3:1 for cleaning. After cleaning, the 500 nm deep trenches were completely filled without collapse.

[0084] Comparative Example 2: To highlight the necessity of the parameters (shrinkage rate and specific developer) defined in the claims of this invention, Comparative Example 2 is provided. This comparative example also adopts the "coating first, curing later" leveling approach, but uses conventional methods in material selection and cleaning process. The specific steps are as follows:

[0085] The same ITO glass substrate and P1 scribing parameters (groove width 40 μm, depth 150 nm) as in Example 1 were used.

[0086] High-shrinkage conventional adhesive: Coating with commercially available conventional acrylic UV adhesive, which has a UV-cured volume shrinkage rate of up to 8.5%.

[0087] Laser precision direct writing is used to cure the inside of the trench.

[0088] Cleaning with conventional single solvent: After curing, instead of using the specially formulated PGMEA mixture of this invention, clean with pure isopropanol (IPA) or conventional high-pressure pure water.

[0089] Morphological characterization results: After cleaning with pure IPA, it was found that due to the polarity of the single organic solvent, although the uncured colloid was washed away, the cured acrylate colloid in the trench underwent severe "swelling," forming an abnormal step of about 80 nm high above the P1 trench. At the same time, due to the high shrinkage rate of the adhesive itself (8.5%), a significant "U-shaped collapse" appeared in the central region of the cured colloid. This resulted in the process, originally intended to fill the gaps, producing an extremely rough microstructure.

[0090] The organic solar cell tandem modules prepared in all the above embodiments and comparative examples were tested for photoelectric performance under a standard solar simulator. Simultaneously, the morphology of the cleaned P1 interface was characterized using a profilometer. The results are summarized in the table below:

[0091]

[0092] As can be seen from the comparison, Examples 1 to 4, which adopt the core parameters of the present invention, have achieved excellent photoelectric conversion efficiency, which is consistently above 13.5%, regardless of whether they are on rigid / flexible substrates or in deep / shallow trenches.

[0093] The data from Comparative Example 2 strongly demonstrates that simply considering the idea of ​​"filling" is insufficient. If the parameters for shrinkage control and the PGMEA special mixed cleaning solution specified in this invention are not strictly followed, the cured colloid will swell and collapse, failing to form an ideal stepless interface. Furthermore, its device performance (9.8%) will still be significantly lower than that of the embodiments of this invention. This fully demonstrates the close coordination and outstanding substantive features among the various technical characteristics of this invention.

[0094] The above description is merely a specific embodiment of the invention, but the scope of protection of the invention is not limited thereto. Any variations or substitutions conceived without inventive effort should be included within the scope of protection of the invention. Therefore, the scope of protection of the invention should be determined by the scope defined in the claims.

Claims

1. A method for preparing an organic solar cell module based on a P1 groove filling technique, characterized by: Includes the following steps: S1: Provide a transparent conductive substrate, and use a laser to etch P1 lines on the transparent conductive substrate to form independent strip conductive electrodes and P1 trenches. The P1 trenches provide a defined micro-nano-level physical space for subsequent filling of insulating materials. S2: Apply insulating adhesive to the transparent conductive substrate, and use capillary action and solution leveling properties to fill the P1 trench space with the insulating adhesive. S3: Selective UV curing process is adopted. Based on the spatial distribution of the P1 trench, only the insulating adhesive inside the P1 trench is photocured, while the insulating adhesive outside the P1 trench remains in liquid state. This creates a difference in the physicochemical properties of solid and liquid states in the same coating. S4: Clean the transparent conductive substrate with a developing cleaning solution to selectively remove the uncured liquid UV insulating adhesive outside the P1 trench, while retaining the cured adhesive inside the trench, so that the cured UV insulating adhesive inside the P1 trench is flush with the surrounding exposed substrate surface, forming a stepless flat interface. S5: Eliminate stress concentration points in crystallization by relying on a smooth, stepless interface, and sequentially deposit and prepare other functional layers of organic solar cells on the interface.

2. The method for fabricating an organic solar cell module based on P1 trench filling technology according to claim 1, characterized in that: The insulating adhesive is applied using a scraping or slot coating method, with the wet film thickness controlled at 1-3 μm. The viscosity of the insulating adhesive is set at 15-45 mPa·s, and the UV insulating adhesive is configured to have a light-curing volume shrinkage rate of less than 3% to prevent volume collapse after photocrosslinking, which would damage the stepless, flat interface.

3. The method for fabricating an organic solar cell module based on P1 trench filling technology according to claim 2, characterized in that: The insulating adhesive is made of any one or more combinations of acrylic UV adhesive, epoxy resin UV adhesive, polyurethane UV adhesive, or organic-inorganic hybrid UV transparent insulating adhesive. The material system contains a photoinitiator that precisely matches the wavelength of the selective ultraviolet exposure light source in step S3, so as to ensure that the adhesive triggers a rapid cross-linking reaction only under a specific ultraviolet band.

4. The method for fabricating an organic solar cell module based on P1 trench filling technology according to claim 1, characterized in that: In step S1, while performing P1 etching and scribing, reference mark points are etched at the substrate edge. In step S3, the selective ultraviolet exposure curing process specifically includes: The interior of the P1 trench was precisely irradiated and cured using a picosecond pulsed ultraviolet laser. The precise irradiation curing system, combined with a high-precision coaxial organic solar cell D-vision recognition and tracking system, automatically calculates and compensates for the current substrate position deviation by capturing the reference Mark point generated in step S1, thereby guiding the ultraviolet laser beam to precisely scan and write along the center line of the P1 trench, limiting the curing crosslinking reaction to occur only within the physical boundary of the P1 trench.

5. The method for fabricating an organic solar cell module based on P1 trench filling technology according to claim 1, characterized in that: The selective ultraviolet curing process further includes: A mask with a light-transmitting slit array is provided, and a visual positioning system is used to make the light-transmitting slit array correspond one-to-one with the P1 groove array in spatial position; A high-power ultraviolet LED surface light source is used to globally expose the substrate through the mask. The light-blocking area of ​​the mask is used to block ultraviolet light from reaching the outside of the P1 trench, so that ultraviolet light can only pass through the slit to irradiate the P1 trench area, thereby achieving one-time local curing of the insulating adhesive in the trench.

6. The method for fabricating an organic solar cell module based on P1 trench filling technology according to claim 1, characterized in that: The developing and cleaning solution is a mixture of isopropanol and propylene glycol methyl ether acetate in a volume ratio of 1:1 to 3:

1. This mixture is configured to have a high efficiency in dissolving uncured liquid UV insulating adhesive, while maintaining chemical inertness to the cross-linked and cured insulating adhesive in S3.

7. The method for fabricating an organic solar cell module based on P1 trench filling technology according to claim 6, characterized in that: The cleaning process in S4 specifically includes: cleaning with low-pressure spray combined with megasonic waves, utilizing the cavitation effect of megasonic waves to accelerate the peeling of liquid colloids with the developing cleaning solution, and the physical impact force of the low-pressure spray is set to be less than the adhesion force between the cured insulating adhesive and the inner wall of the P1 trench. The cleaning time is 15-30 seconds. After cleaning, the product is rinsed with isopropyl alcohol and dried with a nitrogen air knife.

8. The method for fabricating an organic solar cell module based on P1 trench filling technology according to claim 1, characterized in that: Before and after laser etching of P1 in step S1, an automated pre-cleaning process for the transparent conductive substrate is included. The pre-cleaning process includes, in sequence: brush pre-washing, dual-frequency ultrasonic cleaning, two-stage ultrapure water countercurrent rinsing, air knife drying, hot air drying, and UV ozone activation. The UV ozone activation process is used to improve the hydrophilicity of the substrate surface, thereby promoting the uniform, pore-free spreading of the UV insulating adhesive in the P1 trench in step S2.

9. The method for fabricating an organic solar cell module based on P1 trench filling technology according to claim 1, characterized in that: The organic solar cell in S5 adopts a nip formal structure or a pin inverse structure; the conductive layer material of the transparent conductive substrate in S1 includes any one or a combination of at least two of ITO, FTO, AZO, ATO, IGO or BZO.

10. The method for fabricating an organic solar cell module based on P1 trench filling technology according to claim 1, characterized in that: The width of the P1 trench is 20-80 μm and the depth is 50-1000 nm. This size range is configured to match the viscosity of the UV insulating adhesive in step S2 to ensure complete capillary penetration of the adhesive. The laser used is an infrared nanosecond pulse laser or a picosecond pulse laser.

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