Concentrator-solar cell integrated structure and preparation method thereof

Abstract

The invention provides a preparation method of a condenser-solar cell integrated structure. The preparation method comprises the following steps: preparing an LSC substrate; preparing a flexible solar cell and a flexible optical packaging layer on the substrate in sequence; plasma processing is carried out on the surface of the flexible optical packaging layer and the surface of the to-be-bonded edge of the LSC substrate; coating the pretreated surface with a silane coupling agent solution; flexible optical cement with the matched refractive index is evenly coated on any preprocessed surface, then the welt structure and the edge of the waveguide body are precisely aligned and attached, and interface bubbles are removed; and curing the flexible optical cement to obtain the condenser-solar cell integrated structure. According to the preparation method provided by the invention, the flexible thin film is used as the substrate, so that the whole attached cell original part has ductility matched with the flexible LSC body, and interface chemical bonding is combined, so that repeated bending can be borne, and layering is avoided. The invention also provides a condenser-solar cell integrated structure.

Description

Technical Field

[0001] This invention belongs to the field of flexible photovoltaic device technology. Specifically, it relates to a concentrator-solar cell integrated structure and its fabrication method; more specifically, it relates to an edge-collecting photon energy-harvesting structure for integrating a substrate of a flexible light-emitting solar concentrator and a flexible solar cell, and a high-performance integration method of the structure with the concentrator and the solar cell body. Background Technology

[0002] Luminescent solar concentrators (LSCs) are a technology for building-integrated photovoltaics (BIPV), typically integrating a waveguide body doped with luminescent materials with solar cells attached to its edge. In the waveguide structure, the luminescent material generally absorbs sunlight and emits photons of a specific wavelength, transmitting the light to the edge via the waveguide effect, where it is converted into electrical energy by the attached solar cells. Based on this principle, the luminescent material doped within the waveguide structure generally needs to have a large Stokes shift between the absorption band edge and the emission peak, and be able to produce high luminescence quantum efficiency, thereby achieving high power output from the edge-mounted solar cells. With the rapid development of the consumer electronics market and multi-scenario battery products, the industrialization demand for flexible electronics technology is increasing, making the development of flexible LSCs increasingly important for their application in non-planar scenarios such as curved buildings and wearable devices. Accordingly, to better match flexible LSC devices, exploring edge-mounted flexible solar cells (FSCs) is imperative.

[0003] However, when integrating flexible LSCs and FSCs, mismatch often occurs at the bonding interface between them, leading to a significant degradation in device performance and severely hindering its further development. To address this problem, existing technologies attempt to directly mechanically bond the FSC to the edge of the LSC. However, this introduces a series of additional challenges:

[0004] 1) Interface optical loss: The refractive index of the adhesive and the LSC / FSC surface is often mismatched, which will produce a large Fresnel reflection loss at the interface.

[0005] 2) Poor mechanical reliability: After the device is integrated, simple physical bonding will cause insufficient interface adhesion under dynamic bending, which will make it very easy to delaminate.

[0006] 3) Insufficient weather resistance: LSC-FSC devices are usually sensitive to water, oxygen, and high temperature. If the edge-mount structure is not properly packaged, it will lead to rapid degradation of the active materials inside the structure, which will cause device failure.

[0007] Therefore, there is an urgent need to develop an integrated structure of a concentrator and a solar cell and its fabrication method. Summary of the Invention

[0008] The purpose of this invention is to provide a concentrator-solar cell integrated structure and its fabrication method, aiming to solve the technical problem in the prior art where mismatch easily occurs at the bonding interface between flexible LSC and FSC, resulting in a significant decrease in device performance.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a method for fabricating an integrated concentrator-solar cell structure, comprising the following steps:

[0010] Fabrication of LSC substrate;

[0011] Flexible solar cells and flexible optical encapsulation layers are sequentially fabricated on a substrate;

[0012] Plasma treatment was performed on the surface of the flexible optical packaging layer and the edge surface of the LSC substrate to be bonded, respectively;

[0013] A silane coupling agent solution is coated onto the pretreated surface;

[0014] A flexible optical adhesive with a matching refractive index is uniformly applied to any pre-treated surface. Then, the edge-fitting structure is precisely aligned and bonded to the edge of the waveguide body to eliminate interface bubbles.

[0015] Curing flexible optical adhesive to obtain an integrated structure of concentrator-solar cell.

[0016] Preferably, the LSC substrate is a polyethylene naphthalate plate, and the thickness of the LSC substrate is 0.1-10cm.

[0017] Preferably, the flexible solar cell is a perovskite solar cell or / and an organic solar cell or / and a quantum dot thin-film solar cell.

[0018] Preferably, the flexible optical encapsulation layer is an alumina / zirconia composite film prepared by atomic layer deposition and / or a flexible water-blocking silicone layer.

[0019] Preferably, the refractive index of the flexible optical adhesive layer is between that of the LSC substrate and the flexible optical encapsulation layer.

[0020] Preferably, the flexible optical adhesive layer is selected from UV-curable silicone-based optical adhesives and / or epoxy-modified acrylate optical adhesives.

[0021] Preferably, the coating of the pretreated surface with a silane coupling agent solution comprises: an aminosilane or / and methacryloxysilane dispersed in a 1-5 wt% aqueous alcohol solution.

[0022] Preferably, coating the pretreated surface with a silane coupling agent solution includes: coating using a spin coating process, followed by thermal curing after coating; wherein the spin coating speed is 3000 rpm and the spin coating time is 1 min; the thermal curing temperature is 50-150℃ and the curing time is 0.1-100 min.

[0023] A concentrator-solar cell integrated structure is prepared based on the preparation method of the concentrator-solar cell integrated structure as described in any one of the above.

[0024] Preferably, the system includes an LSC substrate, a flexible optical encapsulation layer, and a flexible solar cell stacked sequentially; wherein the LSC substrate is a flexible polymer film; the flexible optical encapsulation layer covers the interface between the LSC substrate and the flexible solar cell; and the flexible optical encapsulation layer is bonded to the edge of the LSC substrate by a flexible optical adhesive layer.

[0025] The beneficial effects of the integrated concentrator-solar cell structure and its fabrication method provided by this invention are as follows: Compared with existing technologies, using a flexible thin film as a substrate enables the entire attached cell component to possess ductility matching that of the flexible LSC body. Combined with interfacial chemical bonding, it can withstand repeated bending, avoid delamination, and exhibit excellent flexibility and reliability. Through proprietary refractive index-matching optical adhesive and interfacial bonding technology, interfacial light reflection loss is minimized, ensuring efficient photon transmission from the waveguide to the cell, resulting in extremely high optical efficiency. The attached structure itself integrates a flexible optical encapsulation layer, avoiding thermal stress delamination of the substructure at high temperatures, providing dual protection for the water- and oxygen-sensitive flexible cell, significantly improving the device's operating life, and exhibiting excellent encapsulation and stability. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, 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 present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 The experimental results of water droplet contact angle test verification of the waveguide edge of the flexible LSC and the encapsulation layer of the FSC in Example 1 after oxygen plasma treatment;

[0028] Figure 2 This is a schematic diagram of the photoelectric conversion efficiency of the product in Example 1 after a bending test.

[0029] Figure 3This is a schematic diagram of the photoelectric conversion efficiency of the product in Example 2 after a bending test.

[0030] Figure 4 This is a schematic diagram of the photoelectric conversion efficiency of the product in Example 3 after a bending test.

[0031] Figure 5 A schematic diagram of a flexible LSC-FSC integrated structure provided by the present invention;

[0032] Figure 6 for Figure 5 A magnified schematic diagram of the structure at point a is shown.

[0033] 1. LSC substrate; 2. Flexible optical encapsulation layer; 3. Flexible solar cell. Detailed Implementation

[0034] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0035] Please refer to the following: Figures 1 to 6 The present invention will now describe a method for fabricating a flexible LSC-FSC integrated structure. The method for fabricating the concentrator-solar cell integrated structure includes the following steps:

[0036] Step S1: Prepare the LSC substrate 1 and the attachment structure separately. The attachment structure preparation includes: sequentially preparing the flexible solar cell 3 and the flexible optical encapsulation layer 2 on the substrate to obtain an independent attachment structure; wherein the substrate is a polymer thin film substrate (such as CPI). The flexible solar cell 3 is prepared on the substrate, and the flexible optical encapsulation layer 2 is on top of the top electrode (top surface) of the cell.

[0037] Step S2, Interface Pretreatment: Plasma treatment is performed on the surface of the flexible optical encapsulation layer 2 and the edge surface of the waveguide body (i.e., the LSC substrate 1) to be bonded (i.e., the side surface of the LSC substrate 1). The surface of the flexible optical encapsulation layer 2 is the end face of the flexible optical encapsulation layer facing away from the flexible solar cell. The plasma treatment uses oxygen or argon plasma with a power of 200-400W and a treatment time of 30-90s, preferably 300W and 30s.

[0038] Step S3: Coating Coupling Agent: A layer of silane coupling agent solution is coated onto the pretreated surface, wherein the pretreated surface includes: the surface of the flexible optical packaging layer 2 and the edge surface of the waveguide body to be bonded. Preferably, it is an aminosilane or methacryloxysilane dispersed in a 1-5 wt% water-alcohol solution. The coating process can be one or more of different methods such as spin coating / spray coating. Spin coating is preferred. The spin coating speed is 3000 rpm and the spin coating time is 1 min. Pre-curing is performed by heat curing at a temperature of 50-150℃, preferably 80℃, and a curing time of 0.1-100 min, preferably 10 min.

[0039] Step S4, Applying optical adhesive and bonding: Apply flexible optical adhesive with matching refractive index evenly to any pre-treated surface, and then precisely align and bond the edge structure with the edge of the waveguide body to eliminate interface bubbles; wherein, any pre-treated surface includes: the surface of the flexible optical encapsulation layer 2 and / or the edge surface of the LSC substrate 1.

[0040] Step S5, Curing and Molding: Use ultraviolet light to cure the flexible optical adhesive to form a strong opto-mechanical interface.

[0041] This invention also provides an integrated structure of a concentrator and a solar cell, which can be referred to in conjunction with the invention. Figures 1 to 6 The structure adopts a pre-designed integrated architecture, consisting of an LSC substrate 1, a flexible optical encapsulation layer 2, and a flexible solar cell 3, arranged from the inside out along the LSC extending to the FSC. Specifically, the LSC substrate 1 can be a flexible polymer film; the flexible optical encapsulation layer 2 covers the LSC / FSC interface; and the flexible solar cell 3 can be a flexible solar cell fabricated on a polymer film substrate. The flexible optical encapsulation layer 2 is bonded to the edge of the LSC substrate 1 of the flexible LSC through a flexible optical adhesive layer with a matching refractive index.

[0042] In some feasible embodiments, the LSC substrate 1 may be made of polyethylene naphthalate (PEN) material, and the thickness of the LSC substrate 1 ranges from 0.1 to 10 cm, preferably 1 to 5 cm. This achieves excellent bending performance and high-density photon transmission performance.

[0043] In some feasible embodiments, the flexible solar cell 3 (FSC) is a perovskite solar cell and / or an organic solar cell and / or a quantum dot thin-film solar cell. The polymer film substrate may be a colorless polyimide film (CPI).

[0044] In some feasible embodiments, a flexible optical encapsulation layer 2 is fabricated on the top layer of the flexible solar cell 3. Specifically, the flexible optical encapsulation layer 2 is an alumina / zirconia composite film or a flexible water-blocking silicone layer prepared by atomic layer deposition. The thickness of the flexible optical encapsulation layer 2 ranges from 0.1 to 1000 mm, preferably 5 to 20 mm. The flexible optical encapsulation layer 2 ensures the integrated stability and weather resistance of the flexible device.

[0045] In some feasible embodiments, the refractive index of the flexible optical adhesive layer is between that of the waveguide body material (LSC substrate) and the refractive index of the flexible optical encapsulation layer. The refractive index range of the flexible optical adhesive layer is 1.45-1.55. The optical adhesive used for the flexible optical adhesive layer is a UV-curable silicone-based optical adhesive or an epoxy-modified acrylate optical adhesive.

[0046] This invention provides a concentrator-solar cell integrated structure and its fabrication method. Through an innovative "sandwich" design and interface engineering, the mechanical adhesion at the interface between the two is significantly improved, and the refractive index at the interface is adapted. By finely controlling the bonding components, the interface stress generated at high temperature is further significantly reduced, and the erosion of the interface by environmental water and oxygen is mitigated. This effectively solves the integration problem of flexible LSC in multiple dimensions of optics, mechanics, electricity, heat and stability, and fundamentally realizes the integrated integration of flexible LSC and FSC.

[0047] This invention provides a method for fabricating an integrated concentrator-solar cell structure. Using a flexible thin film as a substrate, the entire attached cell component possesses ductility matching the flexible LSC body. Combined with interfacial chemical bonding, it can withstand repeated bending, avoid delamination, and exhibits excellent flexibility and reliability. Through proprietary refractive index-matching optical adhesive and interfacial bonding technology, interfacial light reflection loss is minimized, ensuring efficient photon transmission from the waveguide to the cell and achieving extremely high optical efficiency. The attached structure itself integrates a flexible optical encapsulation layer, preventing thermal stress delamination of the substructure at high temperatures. This provides dual protection for the water- and oxygen-sensitive flexible cell, significantly improving the device's lifespan and demonstrating excellent encapsulation and stability.

[0048] This process method is applicable to flexible LSCs with different core materials such as PET, PEN, and PDMS, and has good versatility and strong process universality.

[0049] The structure prepared according to the method for preparing the integrated concentrator-solar cell structure provided in this application not only has a solid mechanical bond, but also achieves efficient optical coupling and good weather resistance, effectively promoting the practical application of flexible LSC technology.

[0050] Example 1

[0051] The fabrication method of the integrated concentrator-solar cell structure includes the following steps:

[0052] The flexible LSC substrate 1 used in this embodiment is prepared by mixing perovskite quantum dots CsPbBr2I1 and PEN precursor. The specific preparation process includes:

[0053] Perovskite quantum dots CsPbBr2I1 were prepared by a hot-injection method. Specifically, under an inert atmosphere, Cs2CO3, PbBr2, oleic acid, and oleylamine were dissolved in an octadecene solvent and reacted at a specific temperature (e.g., 160°C). By controlling the reaction time, quantum dots of uniform size were obtained. After the reaction, the original quantum dots were separated by centrifugation precipitation.

[0054] Subsequently, the obtained quantum dot precipitate was dissolved in toluene (or chlorobenzene, p-xylene) as a solvent, and then hexane was added as an antisolvent for centrifugal washing. This process was repeated 2-3 times to remove excess unreacted precursors and free ligands.

[0055] Finally, the purified quantum dot precipitate was redispersed in fresh toluene (or chlorobenzene) to obtain a solution with a quantum dot colloidal concentration of 0.5 mg / mL.

[0056] The quantum dot toluene dispersion obtained above is mixed with a PEN polymer solution dissolved in the same solvent at a certain volume ratio (preferably 1:100), and stirred for 30 minutes to ensure that the two solutions are mixed evenly.

[0057] The above mixed solution is solidified into a film by means of casting, spin coating, and scraping. The thickness of the PEN film is adjusted by controlling the size of the casting mold and the parameters of spin coating / scraping. After the solvent evaporates, a PEN composite substrate with uniform quantum dot distribution and a thickness of 1 cm is obtained. The surface of the substrate is polished to obtain the target flexible LSC device, namely LSC substrate 1.

[0058] Flexible perovskite quantum dot solar cells were fabricated on a 20 μm thick CPI / ITO film using a solution method combined with vacuum evaporation. The cell structure is: ITO / SnO2 / CsPbBr2I1 / NiOx / ITO. SnO2 and NiO are used in the cell. x All are quantum dot / nanocrystalline structures with a thickness of 10 nm, while CsPbBr2I1 has a thickness of 500 nm. SnO2, NiOx, and CsPbBr2I1 were prepared using solution methods. ITO has a thickness of 100 nm and was prepared using magnetron sputtering.

[0059] After the flexible perovskite quantum dot solar cell was prepared, an Al2O3 / ZrO2 composite film (10 mm) was prepared on the top electrode ITO of the cell by atomic layer deposition as a flexible optical encapsulation layer 2.

[0060] Then, the waveguide edge of the flexible LSC substrate 1 and the surface of the flexible optical packaging layer 2 were treated with oxygen plasma. The power was selected as 300W, the treatment time was 1 min, and the chamber pressure was 40 Pa. After treatment, the substrate was immediately removed. Verification using a water droplet contact angle test showed that the average surface contact angle after treatment decreased from 80° to <30°. Figure 1 This indicates that the surface energy has been significantly increased, and a large number of active groups such as hydroxyl groups have been generated.

[0061] Then, the coupling agent is coated. The process of coating the coupling agent (which needs to be controlled within 1 hour of the previous plasma treatment) includes: taking 5 mL of deionized water and 95 mL of anhydrous ethanol into a clean flask, and slowly adding 2 mL of aminosilane coupling agent while stirring continuously, finally obtaining a clear solution with a concentration of about 2% (v / v).

[0062] The polymer film substrate of the flexible solar cell was placed on a spin coater, and a silane solution was dropped onto the surface. The spin coater was then rotated at low speed (800 rpm) for 10 seconds to ensure uniform spreading of the solution. Subsequently, it was rotated at high speed (2500 rpm) for 30 seconds to remove excess solution, forming an extremely thin and uniform molecular film. The substrate was immediately placed on a hot plate at 80°C for preheating and curing for 10 minutes. This step aims to remove the solvent and promote the formation of strong -Si-O- covalent bonds between the Si-OH bonds of the silane and the hydroxyl groups on the substrate surface, exposing the functional amino groups (-NH2) at the ends of the coupling agent molecules to form a pre-attached structure.

[0063] The application of optical adhesive and bonding involves using UV-curable silicone with a refractive index of 1.50. The optical adhesive is uniformly applied in a continuous "S"-shaped path to the prepared PET waveguide edge surface using a precision dispensing device. The polymer film substrate edge-bonding structure is placed on a precision alignment platform and precisely aligned with the PET waveguide edge coated with optical adhesive. The entire assembly is then rapidly transferred to a simple vacuum chamber, evacuated to -0.06 MPa, and held for 30 seconds, utilizing uniform atmospheric pressure to achieve bubble-free bonding.

[0064] UV curing: The integrated device is removed from the vacuum chamber and placed under a UV point light source at 50mW / cm². 2 Irradiation for 10 seconds under high light intensity (energy dose: 500 mJ / cm²) 2 The initial design has been finalized.

[0065] Then, the light intensity was increased to 100 mW / cm². 2 Irradiate for another 10 seconds (additional energy dose: 1000mW / cm²) 2 This ensures complete curing of the colloid, achieving a strong closure of the bonding structure at the flexible LSC and FSC interfaces.

[0066] Performance testing: After 1000 cycles at a bending radius of 10mm, the photoelectric conversion efficiency of the flexible LSC remains above 93% of its initial value. Figure 2 The interface has no visible layers.

[0067] Example 2

[0068] The difference from Example 1 is that the active layer CsPbBr2I1 of the FSC (flexible solar cell 3) is replaced with a MAPbI3 thin film. The remaining plasma treatment, silane coupling agent, and optical adhesive processes are the same. After the same bending test, the photoelectric conversion efficiency remains above 88% of the initial value. Figure 3 ).

[0069] Example 3

[0070] The difference from Example 1 is that plasma treatment and silane coupling agents were not used; only the same optical adhesive was used for physical bonding. After the same bending test, the efficiency decreased by more than 30%. Figure 4 Furthermore, obvious bubbles and peeling appeared on the interface.

[0071] The above embodiments illustrate the significant effects of the edge-fitting structure and integration method of the present invention in improving the mechanical reliability and optical performance of flexible LSCs. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for fabricating an integrated concentrator-solar cell structure, characterized in that, Includes the following steps: Fabrication of LSC substrate; Flexible solar cells and flexible optical encapsulation layers are sequentially fabricated on a substrate; Plasma treatment was performed on the surface of the flexible optical packaging layer and the edge surface of the LSC substrate to be bonded, respectively; A silane coupling agent solution is coated onto the pretreated surface; A flexible optical adhesive with a matching refractive index is uniformly applied to any pre-treated surface. Then, the edge-fitting structure is precisely aligned and bonded to the edge of the waveguide body to eliminate interface bubbles. Curing flexible optical adhesive to obtain an integrated structure of concentrator-solar cell.

2. The method for fabricating the integrated concentrator-solar cell structure as described in claim 1, characterized in that, The LSC substrate is a polyethylene naphthalate plate, and the thickness of the LSC substrate is 0.1-10cm.

3. The method for fabricating the integrated concentrator-solar cell structure as described in claim 2, characterized in that, The flexible solar cell is a perovskite solar cell or / and an organic solar cell or / and a quantum dot thin-film solar cell.

4. The method for fabricating the integrated concentrator-solar cell structure as described in claim 3, characterized in that, The flexible optical packaging layer is an alumina / zirconia composite film and / or a flexible water-blocking silicone layer prepared by atomic layer deposition.

5. The method for fabricating the integrated concentrator-solar cell structure as described in claim 4, characterized in that, The refractive index of the flexible optical adhesive layer is between that of the LSC substrate and the flexible optical encapsulation layer.

6. The method for fabricating the integrated concentrator-solar cell structure as described in claim 5, characterized in that, The flexible optical adhesive layer uses UV-curable silicone-based optical adhesive and / or epoxy-modified acrylate optical adhesive.

7. The method for fabricating the integrated concentrator-solar cell structure as described in claim 6, characterized in that, The coating of the pretreated surface with a silane coupling agent solution comprises: an aminosilane or / and methacryloxysilane dispersed in a 1-5 wt% aqueous alcohol solution.

8. The method for fabricating the integrated concentrator-solar cell structure as described in claim 7, characterized in that, The process of coating the pretreated surface with a silane coupling agent solution includes: coating using a spin coating process, followed by a heat curing treatment; wherein the spin coating speed is 3000 rpm and the spin coating time is 1 min; the heat curing temperature is 50-150℃ and the curing time is 0.1-100 min.

9. A concentrator-solar cell integrated structure, characterized in that, It is prepared according to the steps described in the method for preparing the integrated concentrator-solar cell structure as claimed in any one of claims 1-8.

10. The integrated concentrator-solar cell structure as described in claim 9, characterized in that, The device includes an LSC substrate, a flexible optical encapsulation layer, and a flexible solar cell, which are stacked sequentially. The LSC substrate is a flexible polymer film. The flexible optical encapsulation layer covers the interface between the LSC substrate and the flexible solar cell. The flexible optical encapsulation layer is bonded to the edge of the LSC substrate by a flexible optical adhesive layer.

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