Large-area methylamine-free perovskite photovoltaic module and preparation method thereof

Abstract

The invention relates to a large-area methylamine-free perovskite photovoltaic module and a preparation method thereof. The photovoltaic module comprises a substrate, a hole transport layer, a perovskite active layer, an interface passivation layer, an electron transport layer and a metal electrode, the hole transport layer is a nickel oxide / organic hole material composite layer; the organic hole material comprises PTAA, P3HT, MoO3 or a self-assembled monomolecular layer. The perovskite solar cell provided by the invention has remarkable advantages in performance and stability, and especially has excellent long-term stability under high-humidity and high-temperature conditions.

Description

Technical Field

[0001] This invention relates to the field of perovskite solar cells, specifically to a crystallization control technology for large-area methylamine-free perovskite modules. By controlling the crystallization pathway and optimizing the film's in-plane uniformity, the technology aims to achieve high-efficiency and high-stability photovoltaic modules. This technology has significant application value in improving photoelectric conversion efficiency and extending the service life of photovoltaic cells. Background Art

[0002] In recent years, perovskite solar cells (PSCs) have become a hot topic in solar cell research due to their high photoelectric conversion efficiency, low cost, and scalable manufacturing capabilities. The light-absorbing materials used in PSCs are typically perovskite-type organic-inorganic hybrid metal halide semiconductors. These materials exhibit excellent photoelectric properties and can be prepared on a large scale using low-cost solution methods, showing promising prospects for industrialization.

[0003] However, despite the many advantages of perovskite solar cells, their widespread commercialization still faces many challenges, especially the large-area perovskite film (currently less than 0.1 cm in the laboratory) that meets the needs of industrialization. 2 , and to meet the industrialization needs, the area must be at least 100cm 2 , which often requires at least 1000 times magnification) to solve the uniformity and stability problems of the perovskite film. In the traditional perovskite film preparation method, methylamine (MA) is used as the A-site ion to improve the phase stability of the film. However, methylamine small molecules are easily decomposed under high temperature conditions, thus affecting the long-term stability of the battery. In addition, in order to improve the stability of the material, in recent years, researchers have tried to introduce methylamine-free ions into the perovskite film system, especially using cesium ions (Cs + )-doped perovskite materials have good thermal stability, but during the large-scale preparation process, component segregation and uneven crystallization often occur, resulting in the performance of the film failing to reach the ideal state. Summary of the Invention

[0004] The purpose of the present invention is to provide a large-area methylamine-free perovskite photovoltaic module and its preparation method in response to the problem of poor uniformity caused by in-plane component segregation faced by current methylamine-free perovskite solar cells. The photovoltaic module adopts a nickel oxide / organic hole material composite hole transport layer, and introduces an ionic liquid as a solvent in the active layer. By utilizing its stability, the control of the crystallization process is achieved, and finally a large-area perovskite film with uniformity and high efficiency in the surface is obtained, which overcomes the in-plane component segregation caused by too fast or uneven crystallization speed, which seriously affects the photoelectric performance and long-term stability of the film. By regulating the solvent ratio and solvent selection, the present invention. To this end, the present invention provides a perovskite film crystallization control method based on solvent regulation, which adjusts the crystallization process by using a combination of solvents with different boiling points, slows down the rate of film crystallization, and thus improves the in-plane uniformity.

[0005] The technical solution of the present invention is:

[0006] A large-area methylamine-free perovskite photovoltaic module, comprising a substrate, a hole transport layer, a perovskite active layer, an interface passivation layer, an electron transport layer, and a metal electrode;

[0007] The substrate is FTO (fluorine-doped tin oxide glass), ITO (indium tin oxide glass), PET / ITO (polyethylene terephthalate substrate) or PEN / ITO (polyethylene naphthalate substrate);

[0008] The hole transport layer is a nickel oxide / organic hole material composite layer; the organic hole material includes PTAA, P3HT, MoO3, or a self-assembled monolayer; the nickel oxide layer has a thickness of 10-30 nm, and the organic hole material has a thickness of 2-30 nm;

[0009] The self-assembled monolayer is one or more of [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), and [2-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz).

[0010] The perovskite active layer is Cs-free and methylamine-free. x FA 1-x PbI3, thickness 300- 650nm ;

[0011] The material of the interface passivation layer is phenylethylamine hydroiodide, phenylethylamine hydrobromide, phenylethylamine hydrochloride or phenylbutylamine hydrochloride / bromide / iodide, which is deposited on the surface of the perovskite to form a quasi-two-dimensional perovskite; the thickness is 1-10 nm;

[0012] The electron transport layer is selected from SnO2, TiO2, chlorine-doped TiO2, C 60 , PCBM, ZnO and any two of them as a composite film structure, with a thickness of 5 to 180 nm.

[0013] The metal is carbon material, copper, gold, silver or titanium;

[0014] The area of ​​the perovskite film is 400 to 900 cm 2 ;

[0015] The method for preparing a large-area methylamine-free perovskite photovoltaic module comprises the following steps:

[0016] 1) Deposit a cavity composite layer on a clean substrate

[0017] Sputtering / blade coating nickel oxide nanoparticles as the first layer with a thickness of 10-30 nm, followed by spin coating, blade coating or immersion in a solution of small organic molecules to construct a hole transport film with a thickness of 2-30 nm;

[0018] The concentration of the solution for soaking the organic small molecules is 1 mg to 5 mg / ml; the organic small molecules are one or more of self-assembled monolayer materials ([2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz), [2-(3,6-dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz));

[0019] 2) Deposition of perovskite active layer on the surface of hole transport layer

[0020] According to the stoichiometric ratio Cs x FA 1-x PbI3 is used to prepare the precursor solution, wherein x is 0.01-0.1, and lead iodide is in excess of 5-15% according to the molar ratio; the precursor solution is evenly coated on the substrate by spin coating or scraping to form a thickness of 300-650nm perovskite films;

[0021] The solvent is a first solvent and a second solvent in a volume ratio of 1:1 to 6; the first solvent is dimethyl sulfoxide (DMSO), and the second solvent is N,N-dimethylformamide (DMF) or N-methylpyrrolidone (NMP);

[0022] The precursor solution also contains an additive, which is formamidine acetate or formamidine propionate;

[0023] The amount of the additive is 0.1%-2% of the total mass of the precursor solution;

[0024] 3) Deposition of a passivation layer on top of the perovskite

[0025] A quasi-two-dimensional ammonium salt passivation layer is deposited on the surface by scraping to passivate surface defects, inhibit interface recombination and defect recombination, improve energy level matching, and thus enhance the photoelectric conversion efficiency and stability of the device.

[0026] 4) Electron transport layer deposition

[0027] Using evaporation or deposition of C 60 About 10-40nm as electron transport layer, or use magnetron sputtering, atomic layer deposition, reactive sputtering to evaporate SnO2 20-40nm as electron transport layer

[0028] 5) Top electrode deposition

[0029] The metal electrode is deposited by magnetron sputtering, reactive sputtering, thermal evaporation and other processes, and the thickness is preferably 5-180nm.

[0030] The essential features of the present invention are:

[0031] The present invention uses a mixed solution of DMSO and DMF / NMP in the perovskite active layer to precisely control the volatility and crystallization rate of the precursor solution. This is because DMSO has a high boiling point, which effectively slows the volatilization rate of the solution, thereby slowing the crystallization process and ensuring uniform deposition of the perovskite material. Furthermore, the addition of ionic liquids such as formamidine acetate and formamidine propionate effectively regulates the dynamic process of crystallization and avoids component segregation in the solution. This allows for uniform mixing of A-site ions (cesium and formamidine) during the crystallization process of the perovskite film, resulting in higher crystal quality and better film uniformity.

[0032] Solvent ratio: In the solvent configuration, DMSO accounts for 10%-60%, and DMF or NMP accounts for 10%-60%. This ratio helps ensure uniform expansion during perovskite crystallization while avoiding component segregation caused by excessive solvent evaporation.

[0033] High-boiling-point solvent additives: The proportion of solvent additives such as formamidine acetate and formamidine propionate in the precursor solution is controlled in the range of 0.1%-2%. These solvents can effectively slow down the crystallization rate of the precursor solution and provide necessary crystallization assistance during the annealing process, ultimately achieving high uniformity of the film.

[0034] The use of high-boiling-point solvents such as DMSO, NMP, and ionic liquids such as formamidine acetate can not only effectively delay the crystallization process of the film, but also optimize the distribution of the perovskite material through its solubility properties. Specifically, these solvents can reduce component segregation during the crystallization process, improve the solubility and uniformity of the perovskite material, and thus improve the film quality of the film. In particular, ionic liquids such as formamidine acetate and formamidine propionate can effectively control the crystallization path through their strong coordination with lead ions, so that the cesium ions and formamidine ions in the film are evenly distributed within the surface, thereby improving the optoelectronic properties and stability of the perovskite film.

[0035] The beneficial effects of the present invention are:

[0036] Through the above technical solutions, the present invention achieves the large-scale preparation of methylamine-free perovskite thin films, in which the crystallization process of the perovskite film is precisely controlled and the film's in-plane uniformity is significantly improved. The optimized solvent ratio, solvent coating process, and annealing process not only effectively solve the problem of in-plane component segregation, but also significantly improve the photoelectric conversion efficiency and the stability of the film's crystallization path, realizing the preparation of high-performance perovskite photovoltaic modules.

[0037] The perovskite solar cells provided by this invention offer significant advantages in performance and stability, particularly in long-term stability under high humidity and high temperature conditions. The corresponding module device efficiency performance increased by 33%, from 18% to 24%, reaching world-class performance. Furthermore, thanks to strategic advantages, the module's operational stability (T85), a dual-85 rigorous aging test, increased tenfold from 100 hours to 1,000 hours. This strategy can meet the requirements for efficient and stable cell performance in the production of large-scale photovoltaic modules, promoting the commercialization of perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Figure 1 Schematic diagram of the structure of the inverted perovskite solar cell of the present invention.

[0040] In the figure: 1. substrate, 2. hole transport layer, 3. cesium-formamidinium-based lead iodine alloy perovskite active layer, 4. interface passivation layer, 5. electron transport layer, 6. metal electrode.

[0041] Figure 2 This is a statistical diagram of the efficiency of the perovskite solar cells prepared in Example 1, Example 2, and Example 3.

[0042] Figure 3 These are stability test curves of the perovskite solar cells prepared in the control example, example 1, example 2, and example 3.

[0043] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0044] To better understand the technical solutions of the present invention, several examples are provided below, demonstrating how, by manipulating the crystallization process, solvent ratio, and additive selection, perovskite films with high uniformity and stability can be obtained, thereby enabling the preparation of efficient and stable large-area perovskite solar cells.

[0045] Example 1: Preparation of perovskite film with additive-optimized solvent ratio

[0046] Precursor solution configuration: 13.3 mmol formamidine iodide (FAI), 1.1 mmol cesium iodide (CsI), 15.5 mmol lead iodide (PbI2), 0.3 mmol cesium chloride (CsCl); solvent: 2 mL N-methylpyrrolidone (NMP) and 8 mL N, N-dimethylformamide (DMF);

[0047] Preparation steps:

[0048] 1. Solution Preparation:

[0049] The precursor was dissolved in a mixture of dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) and stirred for 12 hours until the precursor was completely dissolved.

[0050] 2. Preparation of active layer film:

[0051] Using a slit coater, a large area of ​​perovskite film is applied on the substrate (30cm*30cm FTO substrate) after the hole transport layer is deposited. The wet film is then moved into a vacuum flash evaporation device for vacuum pressure maintenance. 60s Finally, 900cm 2 The film was annealed on a hot plate at 150°C for 20 minutes. A methylamine-free perovskite active layer was obtained, and the perovskite component was preferably Cs x FA 1-x PbI3 (x=0.8, with an additional 7% lead iodide). The hole transport layer is preferably 20 nm of sputtered nickel oxide, and then coated with about 3 nm of MeO-2PACz by knife coating to form a composite hole transport layer.

[0052] 3. Passivation layer and electron transport layer:

[0053] After the film is annealed, a passivation layer is coated and an electron transport layer is prepared. Here, the passivation salt is preferably a 6 mg / ml isopropanol solution of phenylethylamine hydrochloride to obtain a passivation layer of about 3 nm. The electron transport layer is preferably a 30 nm C vapor deposition layer.60 .

[0054] 4. Metal electrode deposition:

[0055] Finally, a metal electrode (copper, about 120nm thick) is deposited, and the module is functionalized and edge-cleaned using laser scribing to complete the preparation of the perovskite solar module device.

[0056] 5. Performance testing:

[0057] The photoelectric conversion efficiency was tested under AM 1.5G illumination, and the stability was tested at the same time. The test environment was 85°C and 85% humidity. The device efficiency was the best at 18.0% ( Figure 2 ), after 100 hours of testing, the performance degradation is greater than 15% ( Figure 3 ).

[0058] Example 2: Preparation of additive-optimized perovskite films

[0059] An additional additive was introduced into the precursor solution: 0.5 mmol of formamidine acetate (FAAc).

[0060] The rest of the steps are the same, and the test device performance achieved the highest efficiency of 23.3% ( Figure 2 ), the stability performance decay is less than 10% after 1000 hours.

[0061] Example 3: Optimizing the Control Effect of Solvent Ratio

[0062] The following additives were additionally introduced into the precursor solution: 0.4 mmol of formamidine acetate (FAAc) and 0.2 mmol of formamidine propionate (FAPr).

[0063] The solvent ratio was adjusted to 1 mL N-methylpyrrolidone (NMP), 1 ml dimethyl sulfoxide (DMSO), and 8 mL N,N-dimethylformamide (DMF).

[0064] The rest of the steps are the same, and the test device performance achieved a maximum efficiency of 24.1%, and the stability of the performance degradation was less than 5% after 1000 hours ( Figure 3 ).

[0065] Performance comparison and analysis

[0066] In order to more intuitively demonstrate the effect of the method of the present invention, the performance comparison of different embodiments and the control experimental group is listed below:

[0067]

[0068] As can be seen from the table above, Examples 2 and 3 significantly improve the photoelectric conversion efficiency by regulating the solvent ratio and the synergistic effect of the additives. Furthermore, the stability of the battery is significantly improved under high temperature and high humidity environments. In particular, Example 3 achieves optimal photoelectric conversion efficiency and stability by utilizing the synergistic effect of formamidine acetate and formamidine propionate.

[0069] Matters not covered by the present invention are known technologies.

Claims

1. A large-area methylamine-free perovskite photovoltaic module, characterized by: The photovoltaic module comprises a substrate, a hole transport layer, a perovskite active layer, an interface passivation layer, an electron transport layer and a metal electrode; The hole transport layer is a nickel oxide / organic hole material composite layer; the organic hole material is PTAA, P3HT, MoO3, or a self-assembled monolayer; the nickel oxide layer has a thickness of 10-30 nm, and the organic hole material has a thickness of 2-30 nm.

2. The large-area methylamine-free perovskite photovoltaic module according to claim 1, characterized in that: The self-assembled monolayer is one or more of [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, and [2-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid.

3. The large-area methylamine-free perovskite photovoltaic module according to claim 1, characterized in that: The substrate is FTO, ITO, PET / ITO or PEN / ITO; The perovskite active layer is Cs x FA 1-x PbI3, thickness 300-650nm; The material of the interface passivation layer is phenylethylamine hydroiodide, phenylethylamine hydrobromide, phenylethylamine hydrochloride or phenylbutylamine hydrochloride / bromide / iodide, which is deposited on the surface of the perovskite to form a quasi-two-dimensional perovskite; the thickness is 1-10 nm; The electron transport layer is selected from SnO2, TiO2, chlorine-doped TiO2, C 60 , PCBM, ZnO and any two thereof film composite structure, the thickness of which is 5 to 180 nm; The metal is carbon material, copper, gold, silver or titanium.

4. The large-area methylamine-free perovskite photovoltaic module according to claim 1, characterized in that: The area of ​​the perovskite film is 400 to 900 cm 2 .

5. The method for preparing a large-area methylamine-free perovskite photovoltaic module according to claim 1, wherein: The method comprises the following steps: 1) Depositing a hole composite layer on the substrate Sputtering / blade coating nickel oxide nanoparticles as the first layer with a thickness of 10-30 nm, followed by spin coating, blade coating or immersion in a solution of small organic molecules to construct a hole transport film with a thickness of 2-30 nm; The concentration of the solution for soaking the organic small molecules is 1 mg to 5 mg / ml; the organic small molecules are one or more of self-assembled monolayer materials ([2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz), [2-(3,6-dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz)); 2) Deposition of perovskite active layer on the surface of hole transport layer According to the stoichiometric ratio Cs x FA 1-x PbI3 is used to prepare a precursor solution, wherein x is 0.01-0.1 and lead iodide is in excess by 5-15% according to a molar ratio; the precursor solution is evenly coated on the substrate by spin coating or doctor blade coating to form a perovskite film; The solvent is a first solvent and a second solvent in a volume ratio of 1:1 to 6; the first solvent is dimethyl sulfoxide (DMSO), and the second solvent is N,N-dimethylformamide (DMF) or N-methylpyrrolidone (NMP); The precursor solution also contains an additive, which is formamidine acetate or formamidine propionate; The amount of the additive is 0.1%-2% of the total mass of the precursor solution; 3) Deposition of a passivation layer on top of the perovskite A quasi-two-dimensional ammonium salt passivation layer is deposited on the surface using a doctor blade method to passivate surface defects, inhibit interface recombination and defect recombination, improve energy level matching, and thus enhance the photoelectric conversion efficiency and stability of the device; 4) Electron transport layer deposition Using evaporation or deposition of C 60 As an electron transport layer, or using magnetron sputtering, atomic layer deposition, reactive sputtering to evaporate SnO2 as an electron transport layer; 5) Top electrode deposition Metal electrodes are deposited using processes such as magnetron sputtering, reactive sputtering, and thermal evaporation.

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