Perovskite solar cell and packaging method thereof

Abstract

The invention discloses application of a perovskite solar cell packaging material, and belongs to the technical field of solar photovoltaics. The perovskite solar cell comprises a conductive substrate or a common substrate, a conductive film, a charge transport layer 1, a perovskite light absorption layer, a charge transport layer 2 and a film electrode. A protective layer is adopted for packaging, and the material of the protective layer is selected from a DOWSIL transparent silicon conformal coating material, a DOWSIL1-2620 silicon conformal coating material or a DOWSIL1-2577 silicon conformal coating material. Hydrophobic substances such as a silicon-based conformal coating material and the like are prepared on the perovskite solar cell through coating, and the cured material is sand-proof, waterproof, moisture-proof and environmental damage-proof, and can provide effective protection for the solar cell. Meanwhile, the silicon-based conformal coating improves the cell performance by optimizing the utilization rate of light; infrared rays and heat can be selectively reflected, and the indoor temperature is kept; and low-temperature packaging can be realized, thermal damage of the perovskite material is avoided, and leakage of lead and toxic substances is prevented. Therefore, the application of the silicon-based conformal coating material has important significance on industrial development of perovskite solar cells.

Description

Technical Field

[0001] This invention belongs to the field of solar cells, and relates to a perovskite solar cell, and more particularly to a perovskite solar cell and its encapsulation method. Background Technology

[0002] With the rapid development of the global economy, the consumption of fossil fuels is constantly increasing. However, existing fossil fuel reserves are limited, and the consumption of fossil fuels exacerbates CO2 emissions, further intensifying the greenhouse effect and accelerating the process of global warming. Optimizing the energy types in the power industry has played a positive role in reducing carbon emissions, which requires the establishment of an energy system based on new energy sources. After years of research, solar cells have developed into the third generation of new high-efficiency solar cells. The third generation of solar cells mainly includes dye-sensitized solar cells, organic thin-film solar cells, and perovskite photovoltaic cells. These types of solar cell devices have high theoretical efficiency, relatively simple manufacturing processes, abundant raw materials, and can be made into thin films, thus gaining unanimous recognition from researchers at home and abroad.

[0003] Perovskite solar cells (PSCs), as a third-generation solar cell concept, possess advantages such as high photoelectric conversion efficiency, low cost, and flexible fabrication capabilities, leading to rapid development in recent years. Currently, the key to realizing the industrial application of perovskite photovoltaic cells lies in cell encapsulation, as the performance of the encapsulation materials directly affects the overall output performance and stability of the photovoltaic module. Currently, ethylene-vinyl acetate copolymer (EVA) is commonly used for encapsulation of perovskite solar cells. However, substances such as acetic acid produced during long-term use of EVA films can easily react with perovskite. The degradation of small molecules like acetic acid leads to decreased material transparency, and the high-temperature lamination process also has a certain impact on perovskite, posing a more severe challenge to encapsulation materials. Summary of the Invention

[0004] The purpose of this patent is to overcome the shortcomings of existing perovskite solar cell encapsulation technology and provide an encapsulation material that can be encapsulated at low temperatures while effectively preventing wind and sand, rain, water, moisture, and environmental damage. It can also effectively extend the service life of perovskite solar cells while solving the problem of complex encapsulation processes.

[0005] To achieve the above objectives, this patent employs the following technical solution: A perovskite solar cell comprises, in sequence, a conductive substrate or a conventional substrate with a conductive thin film, a charge transport layer 1, a perovskite light-absorbing layer, a charge transport layer 2, and a thin-film electrode; it is encapsulated with a protective layer, the material of which is an organosilicon resin coating material selected from DOWSIL transparent silicon conformal coating material, DOWSIL1-2620 transparent silicon conformal coating material, or DOWSIL1-2577 transparent silicon conformal coating material.

[0006] Furthermore, in the above technical solution, the silicone resin coating, i.e., the transparent silicon conformal coating, maintains the shape of the perovskite solar cell, wraps the top layer and sides of the cell, and the coating, together with the substrate, completely encapsulates the perovskite cell.

[0007] Furthermore, in the above technical solution, the charge transport layer 1 or the charge transport layer 2 is a hole transport layer or an electron transport layer.

[0008] Furthermore, in the above technical solution, the conductive substrate is conductive glass, which is covered with a transparent conductive film. The transparent conductive film is fluorine-doped tin oxide (FTO), indium tin oxide (ITO), or zinc oxide doped (AZO, BZO, GZO, AGZO, etc.).

[0009] Furthermore, in the above technical solution, the conductive substrate is FTO glass, ITO glass, stainless steel foil, or a polymer covered with a metal thin film; the hole transport layer is NiO. X x is 0.95–1.05; the electron transport layer is fullerene or its derivatives, copper bath (BCP), zinc oxide, tin oxide or a combination thereof; the thin film electrode layer is a metal thin film (such as aluminum, nickel, chromium, silver, copper, gold, etc.) or a conductive metal oxide such as ITO, FTO, AZO, etc.

[0010] Furthermore, in the above technical solution, the perovskite precursor in the perovskite light-absorbing layer is Cs. x MA y FA z Pb(I) a Br 1-a 3, where 0≤x≤1, 0≤y≤1, 0≤z≤1, x+y+z=1, when x=1, a=1 it is CsPbI3; when y=1, a=1 it is MAPbI3; when z=1, a=1 it is FAPbI3, where some Cs, MA and FA are replaced by alkali metals accounting for less than 10% of their respective metal weight content; the alkali metals include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), francium (Fr) or alkaline earth metals beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra).

[0011] This invention provides a method for encapsulating the above-mentioned perovskite solar cell, comprising the following steps: applying a transparent silicon conformal coating directly or after dilution onto the perovskite solar cell; and using a low-temperature treatment to form a dense and transparent protective film with a density greater than 2.1 g / cm³. 3 Its visible light transmittance exceeds 90%.

[0012] Furthermore, in the above technical solution, the low-temperature treatment involves heating to approximately 60-85°C and holding for approximately 5-15 minutes to form a protective layer.

[0013] Furthermore, in the above technical solution, the protective film is a highly dense protective layer with a density greater than 2.2 g / cm³. 3 .

[0014] Furthermore, in the above technical solution, the protective layer film is a high-transmittance material with a visible spectrum transmittance of over 94%.

[0015] A perovskite solar cell comprises a conductive substrate or a conventional substrate with a conductive thin film (FTO glass, ITO glass, stainless steel foil, metal-coated polymer, etc.), an ITO functional layer, a charge transport layer 1, a perovskite light-absorbing layer, a charge transport layer 2, a thin-film electrode, and a protective layer. The specific fabrication process is as follows: (1) Clean the substrate.

[0016] (2) An ITO functional layer is prepared on a substrate using magnetron sputtering.

[0017] (3) A NiOx transport layer is prepared on a conductive substrate / ITO using magnetron sputtering; x is 0.95-1.05.

[0018] (4) Using a coating method, the perovskite precursor solution is coated onto a conductive substrate / ITO / empty NiO. x After annealing, a perovskite light-absorbing layer is formed on top.

[0019] (5) Using coating / evaporation methods, on conductive substrates / ITO / NiO x PCBM / ZnO or C prepared on PVK 60 / BCP obtains the electron transport layer.

[0020] (6) ITO transparent electrodes and metal electrodes are prepared by sputtering / evaporation to obtain perovskite solar cells.

[0021] (7) Apply any one of the following silicone resin coatings, such as DOWSIL transparent silicon conformal coating material, DOWSIL1-2620 transparent silicon conformal coating material, or DOWSIL1-2577 transparent silicon conformal coating material, onto the perovskite solar cell using a coating method. Heat the coating to approximately 80°C and hold for approximately 10 minutes to form a dense, transparent protective layer with a mass density greater than 2.1 g / cm³. 3 Its visible light transmittance exceeds 90%.

[0022] The conductive substrate in step (1) can be FTO glass, ITO glass, or stainless steel foil, metal film-covered polymer, etc.

[0023] In step (2), the chamber is evacuated to a vacuum level less than 2.0 × 10⁻⁶. -4 At 20 sccm, an Ar / O2 mixture (Ar:O2 = 95:5) is introduced. After the vacuum level in the chamber stabilizes, ITO is sputtered to a thickness of 100 nm-200 nm.

[0024] In step (3), the chamber is evacuated to a vacuum level less than 2.0 × 10⁻⁶. -4 Pa, introduce 12 sccm of Ar / O2 mixed gas (Ar:O2 = 95:5) and 8 sccm of O2, and after the vacuum in the chamber stabilizes, sputter NiO. x x is 0.95-1.05; a hole transport layer is prepared with a thickness of 20nm-100nm.

[0025] The organic perovskite precursor in step (4) includes, but is not limited to, Cs x MA y FA z Pb(I) a Br 1-a 3, where 0≤x≤1, 0≤y≤1, 0≤z≤1, x+y+z=1, when x=1, a=1 it is CsPbI3; when y=1, a=1 it is MAPbI3; when z=1, a=1 it is FAPbI3, where part of Cs 、 MA and FA can be replaced with small amounts (less than 10%) of alkali metals including lithium (Li), sodium (Na), potassium (K), rubidium (Rb), francium (Fr) or alkaline earth metals such as beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). The solution concentration is 0.6 M - 1.5 M, the annealing temperature of the perovskite layer is 70 ℃ - 350 ℃, the annealing time is 1 min - 1000 min, and the thickness is 200 nm - 600 nm.

[0026] In step (5), the electron transport layer can be prepared by blade coating using PCBM or ZnO, or by vapor deposition using C. 60 BCP, with a thickness of 10nm-200nm.

[0027] In step (6), the electrodes can be metal thin films (such as aluminum, nickel, chromium, silver, copper, gold, etc.) or conductive metal oxides such as ITO, FTO, AZO, etc., with a thickness of 100nm-300nm.

[0028] The encapsulation material in step (7) can be any one of the following silicone resin coatings: DOWSIL transparent silicon conformal coating material, DOWSIL1-2620 transparent silicon conformal coating material, DOWSIL1-2577 transparent silicon conformal coating material, etc. Among them, DOWSIL transparent silicon conformal coating material can be directly coated onto the perovskite solar cell without dilution, and dried at 80°C for 10 minutes to form a dense and transparent protective layer with a mass density greater than 2.1 g / cm³. 3 Its visible light transmittance exceeds 90%.

[0029] Furthermore, in the above technical solution, the DOWSIL1-2620 transparent silicon conformal coating material or the DOWSIL1-2577 transparent silicon conformal coating material needs to be diluted with OS-30 silicone oil. The professional solvent dilution ratio is ≤60%. The solvent is slowly added to the coating material while continuously stirring. After dilution, the material is allowed to stand to defoam. The diluted coating material is then applied to the surface of the perovskite solar cell and dried at 80°C for 10 minutes to form a protective layer. The coating thickness is 10nm-10um. After curing, the transmittance is measured. The transmittance of the visible spectrum (including near-ultraviolet and near-infrared, wavelength range 300-1200nm) is >93%.

[0030] Among them, DOWSIL 1-2620 and DOWSIL 1-2577 transparent silicone conformal coating materials feature high transparency and low viscosity (dynamic viscosity approximately 100-1000 centipoise), facilitating spraying, dip coating, and brushing processes. Their main component is polysiloxane, which imparts good flexibility and thermal stability to the coating. After curing, it forms a transparent elastomeric resin film (specific gravity approximately 0.88 uncured, approximately 1.11 cured). It typically cures at room temperature; after solvent evaporation, a tough, wear-resistant surface is formed. Heating can be used to accelerate curing if necessary. The transparent silicone conformal coating materials 1-2620 and 1-2577 have a dielectric strength of 550 V / mil (approximately 22 kV / mm) and a volume resistivity of approximately 4.6 × 10⁻⁶. 13 Its dielectric constant is 2.69 ohm·cm at 100 Hz and 2.68 at 100 kHz. It can operate continuously in a temperature range of -65 to 200 degrees Celsius, effectively preventing corrosion from dust, dirt, static electricity and moisture, while also adhering well to a variety of materials (such as FR4, plastics, metals, aluminum and ceramics).

[0031] This patent provides a packaging material for perovskite solar cells that is not only simple to package, has good light transmittance, high mechanical properties, environmental friendliness, fire resistance, and a wide operating temperature range, but also has high dielectric strength and low dielectric constant, which can provide good insulation protection for electronic components and effectively improve device stability.

[0032] The advantages of the encapsulation material and preparation method used in this invention compared to existing methods are as follows: (1) Perovskite solar cells encapsulated with silicon-based conformal coating materials have good hydrophobicity, which enables the coating to effectively repel moisture and provide waterproof protection for the device. In complex environments, it can effectively prevent electronic devices from short-circuiting or corroding due to moisture. After curing, the material has high transparency, which can effectively reduce light reflection and effectively increase the short-circuit current density (JSC) of the perovskite cell. By optimizing the light utilization rate, the performance of the cell can be improved. It can also selectively reflect infrared rays and heat, and has heat insulation properties, so that it can reflect external heat in summer and retain internal heat in winter, thereby improving the stability and efficiency of the cell. Moreover, the preparation method is simpler, suitable for large-area mass production, and the cost is lower.

[0033] (2) Perovskite solar cells encapsulated with silicon-based conformal coating materials have high dielectric strength and low dielectric constant, which can maintain insulation performance under high voltage and prevent breakdown. This reduces signal transmission losses and improves the performance of electronic devices. Low-temperature encapsulation can also be used to effectively avoid thermal damage to the perovskite material, maintain lattice stability, and reduce the mismatch of thermal expansion coefficients between layers, effectively preventing interface delamination or fracture. This can effectively prevent the leakage of lead and toxic perovskite substances, thereby improving the module yield.

[0034] (3) Silicon-based conformal coating material has a wide operating temperature range (-65℃-200℃). After curing, it can form a tough and wear-resistant surface with certain elasticity and toughness. It can absorb the stress generated by impact and vibration, protect the device from physical damage, and the prepared battery has the advantages of anti-oxidation, water resistance, heat resistance, wear resistance, ozone resistance, and UV radiation protection. It can adapt to various harsh environmental conditions and further expand the application boundaries of perovskite solar cells.

[0035] (4) Silicon-based conformal coating materials can be solvent-free or have low solvent content, which is environmentally friendly. In addition to significant environmental benefits, they also have significant economic benefits. In the future, photochromic and electrochromic functions can be developed to meet the needs of different application scenarios. Attached Figure Description

[0036] Figure 1 Example 1: Comparison of water contact angles before and after preparation of silicone resin coating protective layer for perovskite solar cells; Examples 2 and 3: Contact angles are consistent with those of Example 1.

[0037] Figure 2 This application presents a schematic diagram of a perovskite solar cell structure with an organosilicon resin coating protective layer.

[0038] Figure 3 Comparative Example 1: Schematic diagram of water contact angle of perovskite solar cell. Detailed Implementation

[0039] The implementation method and detailed operation of the present invention are described in detail below with reference to the embodiments and accompanying drawings. However, the present invention is not limited to the embodiments described below, and all methods falling within the scope of the claims should be protected by the present invention.

[0040] The silicone resin coatings used in the following examples were purchased from Dow Corning.

[0041] Example 1: Cleaning the substrate: Clean the substrate with alkaline solution and deionized water and dry it for later use.

[0042] Fabrication of the ITO functional layer: Using magnetron sputtering, the cleaned substrate was placed into the chamber, and the chamber was evacuated to a vacuum level of less than 2.0 × 10⁻⁶. -4 At 20 sccm, an Ar / O2 mixture (Ar:O2 = 95:5) was introduced, with a power of 200 W, a working pressure of 5 mTorr, and a rotation speed of 0.4 rpm, to sputter an ITO functional layer on the surface of a conductive substrate. Charge transport layer 1 is prepared as NiO. x Hole transport layer, x = 0.95–1.05: Using magnetron sputtering, a conductive substrate / ITO is placed in a chamber, and the chamber is evacuated to a vacuum level of less than 2.0 × 10⁻⁵. -4 The system operates at 12 sccm of Ar / O2 mixture (Ar:O2 = 95:5) and 8 sccm of O2, with a power of 140 W, a working pressure of 2 mTorr, and a rotation speed of 0.4 rpm, sputtering a hole transport layer. NiO x After the layer is prepared, the substrate is annealed and crystallized at 300 degrees Celsius for one hour. After the substrate cools naturally, subsequent operations can be carried out.

[0043] Perovskite light-absorbing layer: After annealing, the perovskite light-absorbing layer on the substrate / ITO / NiO is obtained. x Perovskite thin film samples prepared on the substrate. A perovskite precursor solution was coated on the sample surface at a slit width of 200 μm, a travel speed of 0.3 m / min, and a feed rate of 250 rpm. Extraction was performed using an air knife at 0.8 MPa. The completed sample was then annealed at 110 degrees Celsius for 30 min.

[0044] Preparation of charge transport layer 2: The conductive substrate / ITO / NiO is obtained through the above processes. xThe sample was prepared using a PVK matrix, where x ranged from 0.95 to 1.05. An electron transport layer (PCBM) was coated onto the sample surface using a 150 μm slit, a travel speed of 0.4 m / min, a feed rate of 250 rpm, and an air knife pressure of 0.1 MPa. After the electron transport layer was prepared, a 2.5 wt% zinc oxide nanoparticle isopropanol dispersion was coated onto the electron transport layer surface as a protective barrier layer using the same process. The coated sample was then annealed at 100 °C for 10 min.

[0045] Preparation of ITO electrode: The sample prepared according to the above steps was placed in a magnetron sputtering system to sputter a 200 nm ITO transparent electrode. The background vacuum was 20 mTorr, the power was 180 W, the rotation speed was 0.2 rpm, the working gas pressure was 5 mTorr, and 20 sccm of Ar / O2 mixed gas (Ar:O2 = 95:5) was introduced.

[0046] Preparation of the protective layer: After the above steps, we obtained the perovskite solar cell. Using a coating method, DOWSIL transparent silicon conformal coating material was applied to the perovskite solar cell, ensuring complete coverage of the substrate. The protective layer thickness was 10nm-10um. After preparation, it was heated at 80℃ for 10 minutes, and after curing, the light transmittance was greater than 93%.

[0047] Implement Column 2: The protective layer material in Example 1 was replaced with DOWSIL1-2620 transparent silicon conformal coating material, diluted with OS-30 silicone oil, with a professional solvent dilution ratio ≤60%. The solvent was slowly added to the coating material while continuously stirring. After dilution, the material was allowed to stand to defoam. The diluted coating material was then applied to the surface of the perovskite solar cell, ensuring complete coverage of the substrate during the coating process. After preparation, the material was allowed to stand at room temperature for 10 minutes to allow the solvent to evaporate. It was then heated at 80°C for 10 minutes to form a protective layer with a thickness of 10nm-10um. After curing, the light transmittance was greater than 93%. The remaining operating conditions were the same as in Example 1.

[0048] Example 3: The protective layer material in Example 1 was replaced with DOWSIL1-2577 transparent silicon conformal coating material, diluted with OS-30 silicone oil, with a professional solvent dilution ratio ≤60%. The solvent was slowly added to the coating material while continuously stirring. After dilution, the material was allowed to stand to defoam. The diluted coating material was then applied to the surface of the perovskite solar cell, ensuring complete coverage of the substrate. The protective layer thickness was 10nm-10um. After preparation, the material was allowed to stand at room temperature for 10 minutes to allow the solvent to evaporate. Then, it was heated at 80°C for 10 minutes to form the protective layer, with a thickness of 10nm-10um. After curing, the light transmittance was greater than 93%. The remaining operating conditions were the same as in Example 1.

[0049] Comparative Example 1 The difference from Example 1 is that the protective layer material is PET + silicone pressure-sensitive adhesive. The protective layer is prepared by the following steps: the perovskite solar cell is prepared in the same way as in Example 1. The PET film is laid flat on the solar cell, the silicone pressure-sensitive adhesive is applied around the edges, and the cell is laminated at 130°C for 9 minutes. The protective layer is formed after the solar cell cools down to room temperature. The remaining operating conditions are the same as in Example 1.

Claims

1. A perovskite solar cell, characterized in that: The material comprises, in sequence, a conductive substrate or a general substrate with a conductive thin film, a charge transport layer 1, a perovskite light-absorbing layer, a charge transport layer 2, and a thin film electrode; it is encapsulated with a protective layer, the material of which is an organosilicon resin coating material, selected from DOWSIL transparent silicon conformal coating material, DOWSIL1-2620 transparent silicon conformal coating material or DOWSIL1-2577 transparent silicon conformal coating material.

2. The perovskite solar cell as described in claim 1, characterized in that, The protective layer made of silicone resin coating material maintains the shape of the perovskite solar cell, wraps the top and sides of the cell, and the coating and the substrate together completely encapsulate the perovskite cell.

3. The perovskite solar cell as described in claim 1, characterized in that, The charge transport layer 1 and charge transport layer 2 are either hole transport layers or electron transport layers.

4. The application of the perovskite solar cell encapsulation material as described in claim 1, characterized in that, The conductive substrate is conductive glass, with a transparent conductive film covering the glass. The transparent conductive film is fluorine-doped tin oxide, indium tin oxide, or zinc oxide.

5. The perovskite solar cell as described in claim 1, characterized in that, The conductive substrate is a polymer covered by FTO glass, ITO glass, stainless steel foil, or a metal thin film; the hole transport layer is NiO. X The electron transport layer is a fullerene or its derivative, copper bath, zinc oxide, tin oxide or a combination thereof; the thin film electrode layer is a metal thin film, a conductive metal oxide including ITO, FTO or AZO.

6. The perovskite solar cell as described in claim 1, characterized in that, The perovskite precursor in the perovskite light-absorbing layer is Cs. x MA y FA z Pb(I) a Br 1-a 3, where 0≤x≤1, 0≤y≤1, 0≤z≤1, x+y+z=1, when x=1, a=1 it is CsPbI3; when y=1, a=1 it is MAPbI3; when z=1, a=1 it is FAPbI3, or part of it is Cs 、 MA and FA are replaced with alkali metals accounting for less than 10% of their respective metal weight content; the alkali metals include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), francium (Fr) or alkaline earth metals beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra).

7. A method for encapsulating a perovskite solar cell according to any one of claims 1 to 6, characterized in that, Includes the following steps: Silicone resin coating materials are applied directly or in diluted form onto perovskite solar cells, and a low-temperature treatment is used to form a dense, transparent protective film with a density greater than 2.1 g / cm³. 3 Its visible light transmittance exceeds 90%.

8. The packaging method according to claim 7, characterized in that, The low-temperature treatment involves heating to 60-85°C and holding for approximately 5-15 minutes to form a protective layer.

9. The packaging method as described in claim 7, characterized in that, The protective film is a highly dense protective layer with a density greater than 2.2 g / cm³. 3 .

10. The transparent silicon conformal coating material as described in claim 1, characterized in that, The protective film is a highly transparent material with a visible light transmittance of over 94%.

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