A method for treating and preparing a hole transport layer of an organic solar cell

Abstract

The present invention discloses a treatment and preparation method for a hole transport layer of an organic solar cell, which relates to the technical field of solar cells and includes the following steps: S1: preparing a nickel oxide hole transport layer film and cleaning the nickel oxide hole transport layer film with deionized water; S2: preparing a liquid to be adjusted and measuring the initial pH value of the liquid to be adjusted; S3: calculating the volume of sodium hydroxide aqueous solution required, and adding an appropriate amount of sodium hydroxide aqueous solution to the liquid to be adjusted in step S2 to adjust the pH of the solution to a suitable range; S4: evenly spreading the solution in step S3 on the surface of the cleaned nickel oxide hole transport layer film and soaking for 1-15 minutes to ensure sufficient reaction; S5: rinsing the nickel oxide hole transport layer film with deionized water to remove the excess sodium hydroxide aqueous solution, and then drying the rinsed film to complete the post-treatment; the present invention solves the problem of disordered arrangement of ionic liquids at the interface and improves the performance and stability of perovskite devices.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and specifically to a method for treating and preparing a hole transport layer of an organic solar cell. Background Art

[0002] With the continuous consumption of fossil energy, the energy crisis has gradually emerged. Solar energy is a green and clean energy source that is easily accessible. After years of development, the power conversion efficiency of perovskite solar cells has been greatly improved. Among them, inverted perovskite solar cells have received extensive attention due to their simpler and cheaper preparation process, low-temperature film formation, no obvious hysteresis effect, and suitability for fabricating tandem devices in combination with traditional solar cells.

[0003] In inverted perovskite solar cells, common hole transport layers include PEDOT:PSS (an aqueous solution of a polymer, mainly composed of PEDOT (a polymer of 3,4-ethylenedioxythiophene monomers) and PSS (polystyrene sulfonate)), PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]), and NiO x , among which, PEDOT:PSS and PTAA belong to organic materials, and NiO x belongs to inorganic materials. Devices prepared with PEDOT:PSS have a relatively poor energy band match with the perovskite light-absorbing layer and serious interfacial recombination, so the open-circuit voltage of the devices is low. Devices prepared with PTAA have good performance, but the cost of the material itself and the synthesis cost are high, and it is difficult to deposit over a large area. At the same time, there is a potential risk of decomposition in a humid and hot environment.

[0004] As the hole transport layer of inverted perovskite battery devices, NiO x has many advantages. According to the energy level diagrams of each carrier transport layer and the perovskite absorption layer, the HOMO energy level of PTAA is -5.0 eV, the HOMO energy level of PEDOT:PSS is -5.1 eV, while the valence band energy level of the MAPbI3 perovskite material is -5.49 eV, and the valence band energy level of the FAPbI3 perovskite material is -5.50 eV. The energy level mismatch of PTAA and PEDOT:PSS in hole transport is relatively serious. The valence band energy level of NiO x is -5.4 eV, which is close to the valence band energy levels of MAPbI3 and FAPbI3 perovskite materials, and the energy level mismatch problem is small, which can bring a higher open-circuit voltage and efficiency.

[0005] In actual experiments, the inventor found that NiO prepared by DC magnetron sputtering xThere are still some problems restricting the development of thin films. For example, after the preparation of traditional nickel oxide hole transport layer thin films, there will be defects at the contact interface with the perovskite light-absorbing layer. The ionic liquid is disorderly arranged at the interface between nickel oxide and the perovskite light-absorbing layer, and the passivation effect is poor, thereby affecting the performance and stability of perovskite devices. Summary of the Invention

[0006] To solve the defects existing in the prior art, the present invention provides a method for treating and preparing a hole transport layer of an organic solar cell.

[0007] To solve the above technical problems, the present invention provides the following technical solutions:

[0008] The present invention provides a method for treating a hole transport layer of an organic solar cell, comprising the following steps:

[0009] S1: Prepare a nickel oxide hole transport layer thin film and wash the nickel oxide hole transport layer thin film with deionized water;

[0010] S2: Prepare a liquid to be adjusted and measure the initial pH value of the liquid to be adjusted;

[0011] S3: Calculate the volume of the sodium hydroxide aqueous solution required, and add an appropriate amount of the sodium hydroxide aqueous solution to the liquid to be adjusted in step S2 to adjust the pH of the solution to a suitable range;

[0012] S4: Uniformly spread the solution in step S3 on the surface of the washed nickel oxide hole transport layer thin film and soak for 1 - 15 min to ensure sufficient reaction;

[0013] S5: Wash the nickel oxide hole transport layer thin film with deionized water to remove the excess sodium hydroxide aqueous solution, and then dry the washed thin film to complete the post-treatment.

[0014] As a preferred technical solution of the present invention, the pH of the solution in step S3 is 9 - 10.

[0015] As a preferred technical solution of the present invention, the time for washing with deionized water in step S5 is 1 - 5 min;

[0016] The washed thin film is placed in an oven for drying, the drying temperature is 40°C - 70°C, and the drying time is 10 - 30 min.

[0017] As a preferred technical solution of the present invention, both step S4 and step S5 are carried out in air or inert gas.

[0018] As a preferred technical solution of the present invention, the following steps are further included:

[0019] S6: Immerse the nickel oxide hole transport layer film after post-treatment in a fluoride solution for fluorination treatment. Immerse for 1 - 15 min to ensure sufficient reaction, and the concentration of the fluoride solution is 0.1 - 0.5 mol / L.

[0020] As a preferred technical solution of the present invention, the following steps are further included between step S1 and step S2:

[0021] S11: Directly coat the fluoride solution on the surface of the cleaned nickel oxide hole transport layer film, immerse for 1 - 15 min to ensure sufficient reaction, and the concentration of the fluoride solution is 0.1 - 0.5 mol / L;

[0022] S12: Rinse the nickel oxide hole transport layer film with deionized water to remove the unreacted fluoride, and the rinsing time is 1 - 5 min.

[0023] As a preferred technical solution of the present invention, the steps for preparing the nickel oxide hole transport layer film are as follows:

[0024] Deposit the nickel oxide hole transport layer film on the surface of the substrate by sputtering coating. The sputtering conditions are: the flow ratio of oxygen and argon introduced is 150:100, the current is 9 - 12 A, and the working pressure is 0.1 - 1 Pa.

[0025] The present invention also provides a preparation method of an organic solar cell, including the following steps:

[0026] Substrate preparation: Clean the glass substrate containing ITO to ensure that the surface is dust-free and dirt-free;

[0027] Formation of the hole transport layer: Deposit the nickel oxide hole transport layer film by DC magnetron sputtering technology to obtain the hole transport layer, and then perform post-treatment on the nickel oxide hole transport layer film according to S1 - S5;

[0028] Preparation of the active layer: Add methylammonium iodide to an organic solvent, then add lead iodide and stir evenly. After filtration, spin-coat it on the post-treated hole transport layer to obtain the active layer;

[0029] Preparation of the electron transport layer: First disperse PCBM in a chlorobenzene solution, spin-coat it on the active layer, and then perform annealing treatment;

[0030] Silver electrode evaporation: Evaporate silver as the electrode under vacuum conditions.

[0031] As a preferred technical solution of the present invention, in the preparation of the active layer, the spin-coating speed is 1000 - 3000 rpm, and the spin-coating time is 30 - 60 s;

[0032] During the preparation of the electron transport layer, the spin coating speed is 2000 - 4000 rpm, and the spin coating time is 30 - 60 s.

[0033] The present invention also provides an organic solar cell, which is made by using the above-mentioned preparation method of the organic solar cell.

[0034] The beneficial effects of the present invention are as follows:

[0035] 1. For the nickel oxide prepared by DC magnetron sputtering in the present invention, the interface contact between nickel oxide and the perovskite layer is treated with sodium hydroxide solution, which improves the conductivity of the nickel oxide hole transport layer thin film, increases the carrier concentration of the nickel oxide hole transport layer thin film, improves the energy band matching between the nickel oxide hole transport layer thin film and the organic light-absorbing layer, reduces the interface defect density of the nickel oxide hole transport layer thin film, and enhances the ability of the nickel oxide hole transport layer thin film to extract carriers from the organic light-absorbing layer.

[0036] 2. By covering the hole transport layer with an aqueous sodium hydroxide solution and performing annealing treatment, an effective passivation layer can be formed, solving the problem of disordered arrangement of ionic liquids at the interface and improving the performance and stability of the perovskite device.

[0037] 3. The sputtered NiO x thin film contains a large amount of high-valent Ni and reactive groups that are harmful to perovskite. However, the transmittance of the thin film after interface treatment is significantly improved, the charge mobility of nickel oxide is increased, the non-radiative recombination at the interface is effectively inhibited, an interface with a low defect density is obtained, and thus the open-circuit voltage and photoelectric conversion efficiency of the perovskite battery are effectively improved. Description of the Drawings

[0038] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0039] Figure 1 is the process flow chart of the method for treating the hole transport layer of the organic solar cell of the present invention.

[0040] Figure 2 is the schematic diagram of the IV test comparison of the post-treatment method of the nickel oxide hole transport layer thin film of the present invention.

[0041] Figure 3 is the process flow chart of the method for treating the hole transport layer of the organic solar cell in Example 2.

[0042] Figure 4 The process flow chart of the method for treating the hole transport layer of the organic solar cell in Example 3.

[0043] Figure 5This is the process flow chart of the preparation method of the organic solar cell of the present invention. Detailed implementation manners

[0044] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0045] Embodiment 1

[0046] As Figure 1 shown, a method for treating a hole transport layer of an organic solar cell includes the following steps:

[0047] S1: Prepare a nickel oxide hole transport layer thin film and clean the nickel oxide hole transport layer thin film with deionized water.

[0048] S2: Prepare a liquid to be adjusted and measure the initial pH value of the liquid to be adjusted;

[0049] In order to effectively prepare the nickel oxide hole transport layer thin film, the liquid to be adjusted can select some suitable solutions, such as: deionized water, sodium hydroxide solution, and organic solvent solution, etc.;

[0050] Sodium hydroxide solution: Dissolve sodium hydroxide of what concentration in water, and it can be adjusted to the expected pH range in advance, and can be directly used as the liquid to be adjusted. After adjusting the pH, an auxiliary material is adsorbed;

[0051] Organic solvent solution: Such as ethanol, acetone, etc. These solvents can provide different chemical environments, but attention should be paid to pH adjustment and compatibility with subsequent treatments;

[0052] The liquid to be adjusted in the present invention is preferably deionized water because it can provide a stable matrix for the subsequent addition of sodium hydroxide. At the same time, after other components (such as fluorides or salts) are to be introduced, a fluoride solution or an acidic salt solution can be flexibly selected to obtain a suitable reaction environment. Generally speaking, the key to the selection of the liquid to be adjusted is to ensure that there is no negative interference with the performance of the nickel oxide hole transport layer thin film during the treatment process.

[0053] S3: Calculate the volume of the sodium hydroxide aqueous solution required, and add an appropriate amount of the sodium hydroxide aqueous solution to the liquid to be adjusted in step S2 to adjust the pH of the solution to a suitable range. After preparation, the pH of the solution is 9-10. Preferably, after preparation, the pH of the solution is 9.5;

[0054] This stage aims to adjust the pH value of the liquid to be adjusted to the target value of 9.5 by adding a sodium hydroxide solution to the liquid to be adjusted. In order to achieve precise control, this process includes necessary calculations, dropwise addition, and real-time monitoring;

[0055] Use the following formula to calculate the required concentration and volume of NaOH:

[0056] C 1 V 1 =C 2 V 2；

[0057] Where, C 1 is the concentration of the NaOH solution to be added, V 1 is the volume of the NaOH solution to be added (to be calculated), C 2 is the final concentration after the reaction (determined according to the total amount of the liquid to be adjusted and the expected pH, usually experimental correction is required), V 2 is the total volume of the liquid to be adjusted (for example, if there is 100 mL of the liquid to be adjusted, then V 2 = 100 mL). Among them, the concentration of the NaOH solution is 0.1 - 0.5 mol / L.

[0058] S4: Evenly spread the solution in step S3 on the surface of the cleaned nickel oxide hole transport layer film, and soak for 1 - 15 min to ensure sufficient reaction;

[0059] When cleaning the nickel film, the nickel film can be rinsed under flowing deionized water to ensure the removal of surface contaminants;

[0060] Evenly coat the adjusted sodium hydroxide solution on the surface of the nickel film, and then preferably soak it for 5 min. The purpose of this step is to ensure sufficient contact between NaOH and the nickel surface to achieve effective chemical reactions or surface treatments.

[0061] S5: Rinse the nickel oxide hole transport layer film with deionized water to remove the excess sodium hydroxide aqueous solution, and then dry the rinsed film to complete the post-treatment;

[0062] The time for rinsing with deionized water in step S5 is 1 - 5 min. The rinsed film is placed in an oven for drying. The drying temperature is 40°C - 70°C, and the drying time is 10 - 30 min;

[0063] During the process of drying the nickel film, the selection of temperature and duration has an important impact on the quality and performance of the film. The following are some ranges of drying temperature and duration available for the treatment of nickel oxide hole transport layer films:

[0064] Low-temperature drying: 40°C to 50°C, duration: 15 to 30 min, suitable for drying heat-sensitive materials to reduce stress and deformation;

[0065] Medium-temperature drying: 50°C to 70°C, duration: 20 to 40 min, applicable to common standard drying conditions, suitable for drying most films, to promote water evaporation while maintaining the structural stability of the film.

[0066] High-temperature drying: 70°C to 100°C, duration: 10 to 20 min, applicable to cases where faster drying is required, but attention should be paid to avoiding overheating of the film and potential thermal damage. For some materials, too high a temperature may cause phase change or film peeling;

[0067] Preferably, the present invention proposes to dry at 50°C for 20 min.

[0068] Among them, in order to overcome the disordered arrangement at the interface between DC magnetron sputtered nickel oxide and the perovskite light-absorbing layer, and the defects at the interface between nickel oxide and perovskite, the present invention provides a treatment method for the hole transport layer of a perovskite solar cell. By treating the interface contact between nickel oxide and the perovskite layer with a sodium hydroxide solution, the conductivity of the nickel oxide hole transport layer film is improved, the carrier concentration of the nickel oxide hole transport layer film is increased, the energy band matching between the nickel oxide hole transport layer film and the organic light-absorbing layer is improved, the interface defect density of the nickel oxide hole transport layer film is reduced, and the ability of the nickel oxide hole transport layer film to extract carriers from the organic light-absorbing layer is enhanced. By covering the hole transport layer with an aqueous sodium hydroxide solution and performing annealing treatment, an effective passivation layer can be formed to solve the problem of disordered arrangement of ionic liquids at the interface and improve the performance and stability of perovskite devices.

[0069] It should be noted that both step S4 and step S5 are carried out in air or an inert gas (such as nitrogen) to prevent contamination.

[0070] Furthermore, the steps for preparing the nickel oxide hole transport layer film are as follows:

[0071] Deposit the nickel oxide hole transport layer film on the surface of the substrate by sputtering coating. The sputtering conditions are: the flow ratio of oxygen and argon introduced is 150:100, the current is 9 - 12 A, the working pressure is 0.1 - 1 Pa, and a high-purity (99.99%) nickel target is selected to ensure the quality of the NiO x nanometer film.

[0072] Among them, DC magnetron sputtered nickel oxide forms a film by gas ionization and sputtering of the target, depositing target atoms or ions on the substrate. In the process of magnetron sputtering nickel oxide, nickel metal is usually used as the target, gas ions are formed by inert gases such as argon, and a magnetic field is applied to make the ions gather and accelerate, and finally deposit on the substrate;

[0073] The magnetron sputtering nickel oxide process is an important method for preparing nickel oxide hole transport layer thin films. This process has the advantages of fast preparation speed, dense and uniform thin films, and strong controllability. By adjusting the process parameters and the properties of the target, nickel oxide hole transport layer thin films with different thicknesses, structures, and properties can be prepared to meet the requirements of different application fields.

[0074] Specifically, when setting the flow rate ratio of oxygen and argon gases to 150:100, ensure that the concentration of oxygen can promote the oxidation of nickel to form NiO x thin film. Setting the current to 9 - 12A can ensure sufficient bombardment effect and generate enough nickel ions for deposition. For effective DC magnetron sputtering, the generally recommended working vacuum pressure range is from 0.1 Pa to 1 Pa. Further, the working vacuum pressure range is in the low pressure range (0.2 Pa - 0.5 Pa). Within this range, the quality and uniformity of the thin film are better, suitable for the deposition of oxide thin films, which helps to reduce the collision effect of gas molecules on sputtered particles. Preferably, the working vacuum pressure range is 0.36 pa.

[0075] It should be noted that during actual deposition, it is recommended to monitor performance indicators such as the thickness and resistance of the thin film during sputtering in order to further optimize the following conditions:

[0076] Efficiency of the vacuum pump: Ensure that the performance of the pump can be maintained within the recommended vacuum pressure range;

[0077] Control of gas flow rate: Adjust the flow rates of oxygen and argon gases in real time and conduct subsequent thin film analysis to confirm the optimal ratio.

[0078] As Figure 2 shown, it can be clearly seen that after using the treatment method for the hole transport layer of the perovskite solar cell provided by the present invention, the conductivity of the nickel oxide hole transport layer thin film can be significantly improved.

[0079] Example Two

[0080] As Figure 3 shown, a treatment method for the hole transport layer of an organic solar cell includes the following steps:

[0081] S1: Prepare a nickel oxide hole transport layer thin film and clean the nickel oxide hole transport layer thin film with deionized water;

[0082] S2: Prepare the liquid to be adjusted and measure the initial pH value of the liquid to be adjusted;

[0083] S3: Calculate the volume of sodium hydroxide aqueous solution required, and add an appropriate amount of sodium hydroxide aqueous solution to the liquid to be adjusted in step S2 to adjust the solution pH to the appropriate range;

[0084] S4: Uniformly spread the solution in Step S3 over the surface of the cleaned nickel oxide hole transport layer film and soak for 1 - 15 min to ensure sufficient reaction;

[0085] S5: Rinse the nickel oxide hole transport layer film with deionized water to remove the excess sodium hydroxide aqueous solution, and then dry the rinsed film to complete the post - treatment;

[0086] S6: Immerse the nickel oxide hole transport layer film after the post - treatment in a fluoride solution for fluorination treatment, soak for 1 - 15 min to ensure sufficient reaction, the concentration of the fluoride solution is 0.1 - 0.5 mol / L. Preferably, the soaking treatment time is 5 minutes to ensure that the film layer is in full contact with the fluoride solution, and the concentration of the fluoride solution is 0.1 mol / L.

[0087] Example Three

[0088] As Figure 4 shown, a method for treating the hole transport layer of an organic solar cell includes the following steps:

[0089] S1: Prepare a nickel oxide hole transport layer film and clean the nickel oxide hole transport layer film with deionized water;

[0090] S11: Directly coat a fluoride solution on the surface of the cleaned nickel oxide hole transport layer film, soak for 1 - 15 min to ensure sufficient reaction, the concentration of the fluoride solution is 0.1 - 0.5 mol / L. Preferably, the soaking treatment time is 5 minutes to ensure that the film layer is in full contact with the fluoride solution, and the concentration of the fluoride solution is 0.1 mol / L;

[0091] S12: Rinse the nickel oxide hole transport layer film with deionized water to remove the unreacted fluoride, and the rinsing time is 1 - 5 min. Preferably, the rinsing time is 3 min;

[0092] S2: Prepare the liquid to be adjusted and measure the initial pH value of the liquid to be adjusted;

[0093] S3: Calculate the volume of the sodium hydroxide aqueous solution required, and add an appropriate amount of sodium hydroxide aqueous solution to the liquid to be adjusted in Step S2 to adjust the pH of the solution to the appropriate range;

[0094] S4: Uniformly spread the solution in Step S3 over the surface of the cleaned nickel oxide hole transport layer film and soak for 1 - 15 min to ensure sufficient reaction;

[0095] S5: Rinse the nickel oxide hole transport layer film with deionized water to remove the excess sodium hydroxide aqueous solution, and then dry the rinsed film to complete the post - treatment.

[0096] Example 2 and Example 3 respectively present a process of adding a fluorination treatment to the nickel thin film on the basis of Example 1.

[0097] Passivation layer using only NaOH treatment solution: The NaOH treatment solution can remove surface dirt and impurities through reaction with the nickel oxide hole transport layer thin film and initiate surface chemical reactions. It can promote the dissolution of nickel ions to form a passivated nickel hydroxide (Ni(OH) 2 ) layer, enhancing the chemical stability of the film layer. The formed nickel hydroxide layer can provide preliminary passivation to prevent further corrosion. However, the passivation layer is relatively thin, not uniform enough, and the effect is weak, lacking the protection ability for some corrosion environments;

[0098] Passivation layer with fluoride solution coated first and then NaOH treatment solution: Fluorides (such as potassium fluoride or sodium fluoride) can form a fluoride layer of nickel fluoride (NiF 2 ) or other fluorides on the nickel substrate. This layer can provide effective physical protection. The formation of nickel fluoride will affect the subsequent NaOH treatment, enhancing the chemical corrosion resistance of the film layer. NaOH can further improve the surface state on this basis and may promote the uniform distribution of fluorine elements, increasing the thickness and density of the layer. This composite treatment can form a passivation layer with a larger thickness and more complex structure, thereby improving the corrosion resistance. The fluoride layer can seal the surface microstructure of the nickel oxide film to prevent the intrusion of moisture and corrosive substances. At the same time, the presence of fluorine elements can enhance the chemical stability of the film layer and increase the service life in harsh environments.

[0099] From the above comparison, it can be seen that using fluoride solution first and then NaOH treatment solution can generally form a passivation layer with a more complex and effective structure. This layer not only provides physical protection but also can improve chemical stability by increasing the introduction of fluorine elements, thereby enhancing the corrosion resistance.

[0100] The difference between Example 2 and Example 3 is that in Example 2, sodium hydroxide is added first and then fluoride solution, while in Example 3, fluoride solution is added first and then sodium hydroxide.

[0101] To compare the performance of the nickel oxide hole transport layer thin films obtained by the above two treatment methods (adding sodium hydroxide first and then fluoride solution, and adding fluoride solution first and then sodium hydroxide solution), the following performance parameters can be referred to:

[0102] Performance parameters Treatment method 1 (NaOH first) Treatment method 2 (fluoride first) Film thickness (nm) 50-100 60-120 Transmittance (%) 85-90 75-85 Conductivity ( / ) 0.05-0.15 0.03-0.1 <![CDATA[Carrier concentration (10 20 cm −3 ).]]> 1.0-2.0 0.8-1.5 Contact angle (°) 60-70 50-60 Stress (MPa) 30 20

[0103] Table 1 Performance comparison of nickel oxide hole transport layer thin films obtained by two treatment methods

[0104] Among them, the film thickness of Treatment Method 1 (NaOH first) is 50 - 100 nm. A reasonable thickness ensures electrical properties and light transmittance, but being too thin may affect the mechanical properties of the film. The film thickness range of Treatment Method 2 (fluoride first) is 60 - 120 nm. A thicker film may provide better strength and corrosion resistance;

[0105] Treatment Method 1 has a higher light transmittance (85 - 90%), which is suitable for optoelectronic applications, indicating that the optical properties of the film are relatively superior. Treatment Method 2 has a lower light transmittance (75 - 85%), which may reduce its effectiveness in some optoelectronic device applications;

[0106] The conductivity range of Treatment Method 1 is relatively high (0.05 - 0.15 S / m), showing good conductivity performance and being beneficial to charge transport. The conductivity of Treatment Method 2 is relatively low (0.03 - 0.1 S / m), which may result in slightly worse performance in electrical devices;

[0107] Treatment Method 1 has a relatively high carrier concentration (1.0 - 2.0), which helps to improve the effective transport of charges. Treatment Method 2 has a relatively low carrier concentration (0.8 - 1.5), which may affect the conductance performance of the film;

[0108] The contact angle of Treatment Method 1 is 60 - 70°, showing moderate hydrophobicity and being suitable for certain applications. The contact angle of Treatment Method 2 is relatively small, 50 - 60°, showing higher hydrophilicity, which may affect the water wettability and cleaning ability of the film;

[0109] Both Treatment Method 1 and Treatment Method 2 have negative stress, but Treatment Method 1 has a wider stress range, which may have a positive impact on the adhesion and stability of the film;

[0110] In addition, in terms of chemical stability, film denseness, and anti - UV performance, etc., the film obtained by Treatment Method 2 has better effects than the film obtained by Treatment Method 1.

[0111] In summary, Treatment Method 1 (NaOH first) performs better in terms of electrical properties and light transmittance and is suitable for the application of optoelectronic devices. While Treatment Method 2 (fluoride first) has advantages in chemical stability, etc., and is more suitable for applications in harsh environments. For specific application requirements, the most suitable treatment method can be selected according to various performance parameters.

[0112] In the present invention, it is preferred to use the film obtained by Treatment Method 1 (NaOH first), which is more conducive to the use of solar cells.

[0113] Example 4

[0114] Furthermore, as Figure 5 shown, a preparation method of an organic solar cell includes the following steps:

[0115] Substrate preparation: Clean the glass substrate containing ITO to ensure a dust - and dirt - free surface. The material selected is ITO (indium tin oxide). Glass substrates with ITO coatings are widely used in perovskite solar cells due to their excellent transparent conductive properties. The cleaning process is as follows:

[0116] First, use deionized water and a cleaning agent (such as ultrasonic cleaning solution) to preliminarily clean the glass substrate to remove surface dust and oil;

[0117] Secondly, further soak and wipe with acetone or ethanol to ensure the removal of inorganic chemical residues;

[0118] After cleaning, apply nitrogen blow - drying to avoid water residue;

[0119] Before coating, after one deionized water wash, O 2 plasma cleaning can be used to improve surface characteristics and increase interfacial contact with subsequent materials.

[0120] Formation of the hole - transporting layer: Deposit a nickel oxide hole - transporting layer thin film through DC magnetron sputtering technology to obtain the hole - transporting layer, and then post - process the nickel oxide hole - transporting layer thin film according to S1 - S5.

[0121] Preparation of the active layer: Add methylammonium iodide to an organic solvent, then add lead iodide and stir evenly. After filtration, spin - coat it on the post - processed hole - transporting layer to obtain the active layer;

[0122] During the preparation of the active layer, the properties and formation of perovskite materials play a crucial role in the performance of solar cells and other optoelectronic devices. Perovskite materials are usually composed of an organic salt (such as MAI) and an inorganic halide (such as PbI 2 ), and through appropriate dissolution and deposition processes, a perovskite thin film with excellent optoelectronic properties is finally formed, with the chemical formula MAPbI 3；

[0123] The molar ratio of MAI to PbI 2 is set to 1:1, and this ratio is crucial for ensuring the formation of stoichiometric perovskite materials;

[0124] Selection of the organic solvent, DMSO or DMF are commonly used organic solvents that can effectively dissolve MAI and PbI 2 and can form a homogeneous precursor solution at high concentrations, ensuring the complete dissolution of MAI and PbI 2 and contributing to the formation of a uniform and dense perovskite structure during the subsequent spin - coating process;

[0125] After mixing and stirring, preliminary filtration is carried out using a 0.45 µm microporous filter membrane. This process is used to remove larger particulate matter, ensuring that the prepared solution is uniform and particle-free, and avoiding affecting the subsequent spin-coating process.

[0126] Preparation of the electron transport layer: PCBM is first dispersed in chlorobenzene solution and spin-coated on the active layer, followed by annealing treatment. Through heat treatment, the aggregation state of PCBM can be improved, the electron transport performance can be enhanced, and the defect density can be reduced;

[0127] The weight concentration of PCBM is controlled at 20 - 30 mg / ml. It is necessary to ensure that it is fully dissolved in chlorobenzene, and the stirring time should be more than 60 min to promote the full dispersion of PCBM;

[0128] During the annealing process, a nitrogen protection atmosphere is introduced to prevent the film from oxidizing at high temperatures. The annealing temperature and time will affect the aggregation state of PCBM. Usually, thermal annealing is carried out at 120 °C for 30 min. After annealing, the sample is allowed to cool naturally to room temperature to avoid film cracks caused by rapid cooling.

[0129] Evaporation of silver electrodes: Silver is evaporated as an electrode under vacuum conditions. The evaporation of silver electrodes is one of the key steps in the preparation of high-efficiency optoelectronic devices. Preferably, the thickness of the silver electrode film is 100 nm;

[0130] During the preparation of the active layer and the electron transport layer, the spin-coating speed and spin-coating time are also important parameters, which directly affect the uniformity and thickness of the layer. Therefore:

[0131] In the preparation of the active layer, the spin-coating speed is 1000 - 3000 rpm, and the spin-coating time is 30 - 60 s (this period can ensure the formation of a perovskite film with an appropriate thickness (about 100 - 300 nm)) to ensure that the film thickness is between 100 - 300 nm. After spin-coating, it needs to be cooled to room temperature to reduce internal stress, avoid the formation of cracks, and perform heat treatment (about 100 °C, 10 - 30 min) to promote the crystallization of perovskite. The spin-coating speed is selected according to the required film thickness. A higher spin-coating speed usually forms a thinner film, while a lower speed helps to form a thicker film;

[0132] In the preparation of the electron transport layer, the spin-coating speed is 2000 - 4000 rpm, and the spin-coating time is 30 - 60 s.

[0133] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for processing a hole transport layer of an organic solar cell, characterized in that: The following steps are involved: S1: preparing a nickel oxide hole transport layer film and washing the nickel oxide hole transport layer film with deionized water; S2: preparing a liquid to be adjusted and measuring an initial pH value of the liquid to be adjusted; S3: Calculate the required volume of sodium hydroxide aqueous solution, and add the sodium hydroxide aqueous solution to the liquid to be adjusted in step S2 to adjust the pH of the solution to 9-10; Use the following formula to calculate the required NaOH concentration and volume: C1V1=C2V2; Where C1 is the concentration of the NaOH solution to be added, V1 is the volume of the NaOH solution to be added, C2 is the final concentration after the reaction, and V2 is the total volume of the liquid to be adjusted; S4: evenly spread the solution in step S3 on the surface of the cleaned nickel oxide hole transport layer film, and soak for 1-15 minutes to ensure sufficient reaction; S5: Rinse the nickel oxide hole transport layer film with deionized water to remove excess sodium hydroxide aqueous solution, and then dry the rinsed film to complete the post-processing.

2. The method for processing a hole transport layer of an organic solar cell according to claim 1, characterized in that: The deionized water rinsing time in step S5 is 1-5 minutes; The washed film is placed in an oven for drying at a temperature of 40°C-70°C and a drying time of 10-30 minutes.

3. The method for processing a hole transport layer of an organic solar cell according to claim 1, characterized in that: Step S4 and step S5 are both performed under air or inert gas.

4. The method for processing a hole transport layer of an organic solar cell according to any one of claims 1 to 3, characterized in that: The following steps are also included: S6: soaking the post-treated nickel oxide hole transport layer film in a fluoride solution and performing a fluorination treatment, soaking for 1-15 minutes to ensure sufficient reaction, and the concentration of the fluoride solution is 0.1-0.5 mol / L.

5. The method for processing a hole transport layer of an organic solar cell according to any one of claims 1 to 3, characterized in that: The steps between step S1 and step S2 also include the following steps: S11: directly coating the cleaned nickel oxide hole transport layer film with a fluoride solution, soaking for 1-15 minutes to ensure sufficient reaction, the concentration of the fluoride solution is 0.1-0.5 mol / L; S12: Rinse the nickel oxide hole transport layer film with deionized water to remove unreacted fluoride, and the rinsing time is 1-5 minutes.

6. The method for processing a hole transport layer of an organic solar cell according to claim 1, characterized in that: The steps of preparing the nickel oxide hole transport layer film are: A nickel oxide hole transport layer film is deposited on the surface of the substrate by sputtering coating, and the sputtering conditions are: the flow ratio of oxygen and argon gas is 150:100, the current is 9-12A, and the working gas pressure is 0.1-1Pa.

7. A method for preparing an organic solar cell, comprising the method for treating a hole transport layer of an organic solar cell according to any one of claims 1 to 6, characterized in that: The following steps are involved: Substrate preparation: Clean the glass substrate containing ITO to ensure that the surface is dust-free and dirt-free; Formation of the hole transport layer: depositing a nickel oxide hole transport layer film by direct current magnetron sputtering technology to obtain a hole transport layer, and then post-treating the nickel oxide hole transport layer film according to S1-S5; Preparation of the active layer: Add methylammonium iodide to an organic solvent, then add lead iodide and stir evenly, filter and then spin-coat on the post-treated hole transport layer to obtain the active layer; Preparation of electron transport layer: PCBM was first dispersed in chlorobenzene solution, spin-coated on the active layer, and then annealed; Silver electrode evaporation: Silver is evaporated under vacuum conditions as an electrode.

8. The method for preparing an organic solar cell according to claim 7, characterized in that: In the preparation of the active layer, the spin coating speed is 1000-3000 rpm and the spin coating time is 30-60 s; The spin coating speed in the preparation of the electron transport layer is 2000-4000 rpm, and the spin coating time is 30-60 s.

9. An organic solar cell manufactured using the method for manufacturing an organic solar cell according to any one of claims 7 to 8.

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