Hole transport layer and preparation method thereof, perovskite solar cell and power utilization device

Abstract

The invention discloses a hole transport layer and a preparation method thereof, a perovskite solar cell and an electric device, and belongs to the technical field of solar cells. The first solvent with the boiling point being 200-300 DEG C and the alcohol solvent with the boiling point being 55-85 DEG C are adopted as the composite solvent of the hole transport layer precursor solution to adjust the solvent evaporation rate and the SAM film layer state, the electric field with the specific direction and intensity is applied to promote SAM molecules to be directionally arranged, and the orientation of the SAM molecules can be adjusted and controlled from top to bottom; the continuity and uniformity of the hole transport layer are improved, the coverage rate of SAM molecules on the substrate is effectively improved, the photoelectric conversion efficiency of the device is improved, and the consistency of large-area assembly preparation is favorably realized.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to hole transport layers and their preparation methods, perovskite solar cells, and electrical devices. Background Technology

[0002] Perovskite solar cells have become a research hotspot due to their high photoelectric conversion efficiency and low cost. Currently, most high-efficiency perovskite solar cells use self-assembled monolayer (SAM) materials as hole transport layers. The preparation of traditional SAM thin films mainly relies on thermodynamic processes (such as solution immersion, blade coating, spin coating, etc.), which have problems such as slow film formation speed and disordered molecular arrangement, resulting in defects and discontinuities at the interface. It is impossible to effectively passivate interface defects, which greatly limits the photoelectric conversion efficiency of the device and makes it difficult to achieve uniformity of large-area modules.

[0003] Therefore, improving the orientation of SAM molecules on the substrate to enhance their continuity and uniformity is key to improving the photoelectric conversion efficiency of devices and realizing the fabrication of large-area components. Summary of the Invention

[0004] Based on this, the main objective of this application is to provide a method for preparing a hole transport layer. By using a first solvent with a boiling point of 200℃-300℃ and an alcohol solvent with a boiling point of 55℃-85℃ as a composite solvent for the hole transport layer precursor solution, the solvent evaporation rate and SAM film state are adjusted. An electric field of a specific direction and intensity is applied to promote the directional alignment of SAM molecules, thereby improving their continuity and uniformity, thus enhancing the photoelectric conversion efficiency of the device and achieving consistency in the fabrication of large-area components.

[0005] The first aspect of this application provides a method for preparing a hole transport layer, comprising the following steps:

[0006] A hole transport layer precursor solution containing a self-assembled monolayer material and a composite solvent is coated onto a substrate to prepare a self-assembled monolayer semi-dry film with a solvent content of 99wt%-99.98wt%; the composite solvent includes a first solvent with a boiling point of 200℃-300℃ and an alcohol solvent with a boiling point of 55℃-85℃.

[0007] The self-assembled monolayer semi-dry film is subjected to electric field treatment to prepare an electric field-treated self-assembled monolayer thin film; the direction of the electric field is perpendicular to the substrate and extends along the direction of the self-assembled monolayer semi-dry film away from the substrate; the strength of the electric field is 1×10⁻⁶. 5 V / m-5×10 5 V / m;

[0008] The solvent is removed from the self-assembled monolayer film after electric field treatment and annealed to form the hole transport layer.

[0009] In some embodiments, the step of placing the self-assembled monolayer semi-dry film in an electric field to perform electric field treatment to prepare an electric field-treated self-assembled monolayer film includes: using the substrate as the lower electrode connected to the positive electrode and setting the upper electrode connected to the negative electrode, placing the upper electrode above the self-assembled monolayer semi-dry film in a manner parallel to the substrate, applying a voltage to form an electric field, performing electric field treatment on the self-assembled monolayer semi-dry film, and preparing an electric field-treated self-assembled monolayer film.

[0010] In some embodiments, the preparation method satisfies one or more of the following characteristics:

[0011] (1) The voltage is 20V-100V;

[0012] (2) The electric field treatment time is 1 min to 5 min;

[0013] (3) The substrate includes at least one of ITO substrate and FTO substrate;

[0014] (4) The upper electrode includes at least one of a platinum electrode, a carbon-based electrode, and gold-plated glass;

[0015] (5) The distance between the upper electrode and the lower electrode is 100μm-300μm;

[0016] (6) The thickness of the hole transport layer is 0.8nm-3nm.

[0017] In some embodiments, the preparation method satisfies one or more of the following characteristics:

[0018] (1) In the composite solvent, the volume ratio of the first solvent to the alcohol solvent is 1:9-5:5;

[0019] (2) The first solvent includes at least one of triethylene glycol, N-methylpyrrolidone and triethylene glycol methyl ether;

[0020] (3) The alcohol solvent includes at least one of methanol and ethanol;

[0021] (4) In the hole transport layer precursor solution, the molar concentration of the self-assembled monolayer material is 0.1 mM-1 mM.

[0022] In some embodiments, the self-assembled monolayer material includes [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, [3-(3,6-dimethoxy-9H-carbazole-9-yl)propyl]phosphonic acid, [6-(3,6-dimethoxy-9H-carbazole-9-yl)hexyl]phosphonic acid, [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphonic acid, [3-(3,6-dimethyl-9H-carbazole-9-yl)propyl]phosphonic acid, [6-(3,6-dimethyl-9H-carbazole-9-yl)hexyl]phosphonic acid, [1-(3,6-dimethyl-9H-carbazole-9-yl)methyl]phosphonic acid, and [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid. [8-(3,6-dimethyl-9H-carbazole-9-yl)octyl]phosphoric acid, [1-(9H-carbazole-9-yl)methyl]phosphoric acid, (2-(9H-carbazole-9-yl)ethyl)phosphoric acid, [3-(9H-carbazole-9-yl)propyl]phosphoric acid, [4-(9H-carbazole-9-yl)butyl]phosphoric acid, [6-(9H-carbazole-9-yl)hexyl]phosphoric acid, [8-(9H-carbazole-9-yl)octyl]phosphoric acid, [4-(N,N-di(4-methoxyphenylamino)phenyl)propyl]phosphoric acid, 2,3,4,5,6-pentafluorobenzylphosphoric acid, [2-(9H-9'-phenyl-3,3'-dibicarbazole-9-yl)ethyl]phosphoric acid, [4 ... [4-(diphenylamino)phenyl)ethyl]phosphoric acid, [4-(diphenylamino)phenyl)propyl]phosphoric acid, [4-(10H-phenthiazin-10-yl)butyl]phosphoric acid, [2-(7H-dibenzocarbazole-7-yl)ethyl]phosphoric acid, [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid, [3-(3,6-dibromo-9H-carbazole-9-yl)propyl]phosphoric acid, [4-(3,6-dibromo-9H-carbazole-9-yl)butyl]phosphoric acid, [6-(3,6-dibromo-9H-carbazole-9-yl)hexyl]phosphoric acid, [1-(3,6-di-tert-butyl-9H-carbazole-9-yl)methyl]phosphoric acid, [2-(3,6-di-tert-butyl-9H-]phosphoric acid, [3,6-di-tert-butyl-9H-]phosphoric acid, [4-(diphenylamino)phenyl)ethyl ... [Carbazole-9-yl)ethyl]phosphoric acid, [3-(3,6-di-tert-butyl-9H-carbazole-9-yl)propyl]phosphoric acid, [4-(3,6-di-tert-butyl-9H-carbazole-9-yl)butyl]phosphoric acid, [6-(3,6-di-tert-butyl-9H-carbazole-9-yl)hexyl]phosphoric acid, [8-(3,6-di-tert-butyl-9H-carbazole-9-yl)octyl]phosphoric acid, [1-(3,6-diphenyl-9H-carbazole-9-yl)methyl]phosphoric acid, [2-(3,6-diphenyl-9H-carbazole-9-yl)ethyl]phosphoric acid, [3-(3,6-diphenyl-9H-carbazole-9-yl)propyl]phosphoric acid, [4-(3,6-diphenyl-9H-carbazole-9-yl)butyl]phosphoric acid, [6-(3,6-di-tert-butyl ...hexyl]phosphoric acid, [6-(3,6-di-tert-butyl-9H-carbazole-9-yl)ethyl]phosphoric acid, [3-(3,6-di-tert-butyl-9H-carbazole-9-yl)propyl]phosphoric acid, [4-(3,6-di-tert-butyl-9H-carbazole-9-yl)butyl]phosphoric acid, [6-(3,6-di-tert-butyl-9H-carbazole-9-yl)hexyl]phosphoric acid, [6-(3,6-di-tertAt least one of the following: [6-diphenyl-9H-carbazole-9-yl)hexyl]phosphoric acid, [8-(3,6-diphenyl-9H-carbazole-9-yl)octyl]phosphoric acid, [2-(10H-phenoxazine-10-yl)ethyl]phosphoric acid, [4-(3,7-dibromo-10H-phenthiazine-10-yl)butyl]phosphoric acid, and [4-(3,7-dibromo-10H-phenoxazine-10-yl)butyl]phosphoric acid.

[0023] In some embodiments, the coating includes at least one of spin coating, blade coating, slot coating, and inkjet printing;

[0024] And / or, the annealing conditions are: annealing temperature of 70℃-90℃; annealing time of 5min-20min.

[0025] A second aspect of this application provides a hole transport layer prepared by the preparation method described in the first aspect.

[0026] A third aspect of this application provides a perovskite solar cell including the hole transport layer described in the second aspect.

[0027] In some embodiments, the perovskite solar cell includes a substrate, a hole transport layer, a perovskite layer, an electron transport layer, a buffer layer, and a back electrode stacked together.

[0028] A fourth aspect of this application provides an electrical device comprising the perovskite solar cell described in the third aspect.

[0029] The beneficial effects of this application are:

[0030] This application uses a composite solvent containing a first solvent with a boiling point of 200℃-300℃ and an alcohol solvent with a boiling point of 55℃-85℃ as the hole transport layer. This allows for the adjustment of the solvent evaporation rate and film state of the wet film formed by coating the hole transport layer precursor solution. By applying an electric field of a specific intensity perpendicular to the substrate and extending along the semi-dry film direction while maintaining a semi-dry film state, the orientation of SAM molecules can be controlled from top to bottom. This promotes the negatively charged polar anchoring groups in the SAM molecules to approach the substrate, causing the SAM molecules to align in an oriented manner, improving the continuity and uniformity of the hole transport layer, effectively increasing the coverage of SAM molecules on the substrate, and achieving the fabrication of a high-quality, ultra-thin hole transport layer. This improves the photoelectric conversion efficiency of the device and meets the fabrication requirements of large-size devices. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings are only for illustrating preferred embodiments and are not intended to limit this application. Throughout the drawings, the same reference numerals denote the same parts. In the drawings:

[0032] Figure 1 This is a schematic diagram illustrating the directional alignment of SAM molecules induced by an electric field.

[0033] Figure 2 SEM image of an ITO substrate containing a hole transport layer prepared according to Example 1;

[0034] Figure 3 SEM image of the ITO substrate containing the hole transport layer prepared for reference to Comparative Example 1. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer and to provide a more thorough and comprehensive understanding of the disclosure of this application, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. The described embodiments are only some embodiments of this application, and not all embodiments.

[0036] The implementation of this application will be described in detail below with reference to the accompanying drawings. This embodiment is implemented based on the technical solution of this application, and provides detailed implementation methods and specific operation processes, but the protection scope of this application is not limited to the following embodiments.

[0037] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application and in its specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0038] Unless otherwise stated or in case of conflict, the terms or phrases used in this application shall have the following meanings:

[0039] In this application, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" or "at least one" means one or more of two.

[0040] In this application, terms such as "further" and "especially" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0041] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0042] In this application, when numerical intervals (i.e., numerical ranges) are mentioned, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include numerical interval types such as percentage intervals, ratio intervals, and proportion intervals.

[0043] In this application, unless otherwise specified, the temperature parameters are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control. Fluctuations are permitted within ranges such as ±5℃, ±4℃, ±3℃, ±2℃, and ±1℃.

[0044] The term “and / or” as used in this application includes any and all combinations of one or more of the associated listed items.

[0045] Unless otherwise specified, the percentage content mentioned in this application refers to mass percentage for solid-liquid mixtures and solid-phase-solid mixtures, and volume percentage for liquid-phase-liquid mixtures.

[0046] Unless otherwise specified, all percentage concentrations mentioned in this application refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0047] In this application, unless otherwise specified, the temperature parameter can be either constant temperature treatment or treatment within a certain temperature range. The constant temperature treatment allows temperature fluctuations within the precision range controlled by the instrument.

[0048] In this application, room temperature refers to 10℃-35℃, and may further be 20℃-30℃, or even 25±2℃.

[0049] Traditional SAM thin film preparation mainly relies on thermodynamic processes (such as solution immersion, blade coating, spin coating, etc.), which have problems such as slow film formation speed and disordered molecular arrangement, resulting in defects and discontinuities at the interface, making it impossible to effectively passivate interface defects. The bonding between SAM molecules and the substrate is not strong, which greatly limits the photoelectric conversion efficiency of the device and makes it difficult to achieve consistency of large-area components.

[0050] In view of this, this application provides a hole transport layer and its preparation method, a perovskite solar cell, and an electrical device to improve the photoelectric conversion efficiency of the device and achieve consistency in the fabrication of large-area components.

[0051] The first aspect of this application provides a method for preparing a hole transport layer, comprising the following steps:

[0052] A hole transport layer precursor solution containing a self-assembled monolayer material and a composite solvent is coated onto a substrate to prepare a self-assembled monolayer semi-dry film with a solvent content of 99wt%-99.98wt%; the composite solvent includes a first solvent with a boiling point of 200℃-300℃ and an alcohol solvent with a boiling point of 55℃-85℃.

[0053] The self-assembled monolayer semi-dry film is subjected to electric field treatment to prepare an electric field-treated self-assembled monolayer thin film; the direction of the electric field is perpendicular to the substrate and extends along the direction of the self-assembled monolayer semi-dry film away from the substrate; the strength of the electric field is 1×10⁻⁶. 5 V / m-5×10 5 V / m;

[0054] The solvent is removed from the self-assembled monolayer film after electric field treatment and annealed to form the hole transport layer.

[0055] This application uses a composite solvent containing a first solvent with a boiling point of 200℃-300℃ and an alcohol solvent with a boiling point of 55℃-85℃ as the hole transport layer. This allows for the adjustment of the solvent evaporation rate and film state of the wet film formed by coating the hole transport layer precursor solution. By applying an electric field of a specific intensity perpendicular to the substrate and extending along the semi-dry film direction while maintaining a semi-dry film state, the orientation of SAM molecules can be controlled from top to bottom. This promotes the negatively charged polar anchoring groups in the SAM molecules to approach the substrate, causing the SAM molecules to align in an oriented manner, improving the continuity and uniformity of the hole transport layer, effectively increasing the coverage of SAM molecules on the substrate, and achieving the fabrication of a high-quality, ultra-thin hole transport layer. This improves the photoelectric conversion efficiency of the device and meets the fabrication requirements of large-size devices.

[0056] Understandably, a self-assembled monolayer semi-dry membrane with a limited solvent content can be prepared by coating a hole transport layer precursor solution containing a self-assembled monolayer material and a composite solvent onto a substrate to form a wet film, followed by drying the wet film. Drying methods include, but are not limited to, vacuum drying, standing at room temperature for 10-60 seconds (e.g., 10s, 20s, 30s, 40s, 50s, 60s), and heating drying. The solvent content in the self-assembled monolayer semi-dry membrane can be adjusted. During the drying process, the main solvent volatilized is an alcohol solvent with a boiling point of 55℃-85℃, while a small amount of the first solvent at 200℃-300℃ will also volatilize, thus forming a self-assembled monolayer semi-dry membrane with the first solvent at 200℃-300℃ as the main solvent. The solvent content in a self-assembled monolayer semi-dry film can be determined by differential gravimetric analysis. For example, the weight m0 of the substrate, the weight m1 of the substrate containing the self-assembled monolayer semi-dry film, and the weight m2 of the substrate containing the self-assembled monolayer semi-dry film after drying (removing the solvent) can be measured. The weight m of the self-assembled monolayer material can then be calculated by subtracting m0 from m2. 2-0 The weight m of the hole transport layer precursor solution is calculated using m1-m0. 1-0 Then the solvent content in the self-assembled monolayer semi-dry film = (m 1-0 -m 2-0 ) / m 1-0 ×100%.

[0057] In some embodiments, the boiling point of the first solvent may be 200°C, 220°C, 240°C, 260°C, 280°C, 300°C, etc. The boiling point of the alcohol solvent may be 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, etc. It is understood that in this application, boiling point refers to the boiling point at standard atmospheric pressure (101.325 kPa).

[0058] In some embodiments, the solvent content of the self-assembled monolayer semi-dry film can be 99.8wt%-99.98wt%, specifically 99wt%, 99.2wt%, 99.4wt%, 99.5wt%, 99.7wt%, 99.8wt%, 99.9wt%, 99.95wt%, 99.98wt%, etc.

[0059] In some embodiments, the strength of the electric field can be 1×10⁻⁶. 5 V / m, 2×10 5 V / m, 3×10 5 V / m, 4×10 5 V / m, 5×10 5 V / m, etc.

[0060] In some embodiments, the step of placing the self-assembled monolayer semi-dry film in an electric field to perform electric field treatment to prepare an electric field-treated self-assembled monolayer film includes: using the substrate as the lower electrode connected to the positive electrode and setting the upper electrode connected to the negative electrode, placing the upper electrode above the self-assembled monolayer semi-dry film in a manner parallel to the substrate, applying a voltage to form an electric field, performing electric field treatment on the self-assembled monolayer semi-dry film, and preparing an electric field-treated self-assembled monolayer film.

[0061] The above-mentioned electric field setup method is as follows: Figure 1 As shown, under the action of this electric field, the orientation of SAM molecules can be controlled from top to bottom, causing the negatively charged polar anchoring groups in the SAM molecules to approach the substrate, thus promoting the directional alignment of SAM molecules.

[0062] Understandably, using the substrate as the lower electrode is beneficial for increasing the electric field penetration depth, reducing the impact of solvent disturbance and voltage requirements, and improving the consistency of the hole transport layer. The spacing between the upper and lower electrodes can be achieved by using polyimide pads for support between them, or it can be controlled by a micropillar array.

[0063] In some embodiments, the preparation method satisfies one or more of the following characteristics:

[0064] (1) The voltage is 20V-50V, such as 20V, 30V, 40V, 50V, etc.;

[0065] (2) The electric field treatment time is 1 min to 5 min, for example, 1 min, 2 min, 3 min, 4 min, 5 min, etc.;

[0066] (3) The substrate includes at least one of ITO substrate and FTO substrate;

[0067] (4) The upper electrode includes at least one of a platinum electrode, a carbon-based electrode, and gold-plated glass;

[0068] (5) The distance between the upper electrode and the lower electrode is 100μm-300μm, for example, 100μm, 150μm, 200μm, 250μm, 300μm, etc.

[0069] In some embodiments, the preparation method satisfies one or more of the following characteristics:

[0070] (1) In the composite solvent, the volume ratio of the first solvent to the alcohol solvent is 1:9-5:5, for example 1:9, 2:8, 3:7, 4:6, 5:5, etc.;

[0071] (2) The first solvent includes at least one of triethylene glycol, N-methylpyrrolidone and triethylene glycol methyl ether;

[0072] (3) The alcohol solvent includes at least one of methanol and ethanol;

[0073] (4) In the hole transport layer precursor solution, the molar concentration of the self-assembled monolayer material is 0.1mM-1mM, for example 0.1mM, 0.2mM, 0.4mM, 0.6mM, 0.8mM, 1mM, etc.

[0074] It should be noted that, under standard atmospheric pressure, the boiling point of triethylene glycol is approximately 285℃, the boiling point of N-methylpyrrolidone is approximately 202℃-204℃, the boiling point of triethylene glycol methyl ether is approximately 249℃, the boiling point of methanol is 64.7℃, and the boiling point of ethanol is 78.37℃.

[0075] In some embodiments, the self-assembled monolayer material includes [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, [3-(3,6-dimethoxy-9H-carbazole-9-yl)propyl]phosphonic acid, [6-(3,6-dimethoxy-9H-carbazole-9-yl)hexyl]phosphonic acid, [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphonic acid, [3-(3,6-dimethyl-9H-carbazole-9-yl)propyl]phosphonic acid, [6-(3,6-dimethyl-9H-carbazole-9-yl)hexyl]phosphonic acid, [1-(3,6-dimethyl-9H-carbazole-9-yl)methyl]phosphonic acid, and [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid. [8-(3,6-dimethyl-9H-carbazole-9-yl)octyl]phosphoric acid, [1-(9H-carbazole-9-yl)methyl]phosphoric acid, (2-(9H-carbazole-9-yl)ethyl)phosphoric acid, [3-(9H-carbazole-9-yl)propyl]phosphoric acid, [4-(9H-carbazole-9-yl)butyl]phosphoric acid, [6-(9H-carbazole-9-yl)hexyl]phosphoric acid, [8-(9H-carbazole-9-yl)octyl]phosphoric acid, [4-(N,N-di(4-methoxyphenylamino)phenyl)propyl]phosphoric acid, 2,3,4,5,6-pentafluorobenzylphosphoric acid, [2-(9H-9'-phenyl-3,3'-dibicarbazole-9-yl)ethyl]phosphoric acid, [4 ... [4-(diphenylamino)phenyl)ethyl]phosphoric acid, [4-(diphenylamino)phenyl)propyl]phosphoric acid, [4-(10H-phenthiazin-10-yl)butyl]phosphoric acid, [2-(7H-dibenzocarbazole-7-yl)ethyl]phosphoric acid, [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid, [3-(3,6-dibromo-9H-carbazole-9-yl)propyl]phosphoric acid, [4-(3,6-dibromo-9H-carbazole-9-yl)butyl]phosphoric acid, [6-(3,6-dibromo-9H-carbazole-9-yl)hexyl]phosphoric acid, [1-(3,6-di-tert-butyl-9H-carbazole-9-yl)methyl]phosphoric acid, [2-(3,6-di-tert-butyl-9H-]phosphoric acid, [3,6-di-tert-butyl-9H-]phosphoric acid, [4-(diphenylamino)phenyl)ethyl ... [Carbazole-9-yl)ethyl]phosphoric acid, [3-(3,6-di-tert-butyl-9H-carbazole-9-yl)propyl]phosphoric acid, [4-(3,6-di-tert-butyl-9H-carbazole-9-yl)butyl]phosphoric acid, [6-(3,6-di-tert-butyl-9H-carbazole-9-yl)hexyl]phosphoric acid, [8-(3,6-di-tert-butyl-9H-carbazole-9-yl)octyl]phosphoric acid, [1-(3,6-diphenyl-9H-carbazole-9-yl)methyl]phosphoric acid, [2-(3,6-diphenyl-9H-carbazole-9-yl)ethyl]phosphoric acid, [3-(3,6-diphenyl-9H-carbazole-9-yl)propyl]phosphoric acid, [4-(3,6-diphenyl-9H-carbazole-9-yl)butyl]phosphoric acid, [6-(3,6-di-tert-butyl ...hexyl]phosphoric acid, [6-(3,6-di-tert-butyl-9H-carbazole-9-yl)ethyl]phosphoric acid, [3-(3,6-di-tert-butyl-9H-carbazole-9-yl)propyl]phosphoric acid, [4-(3,6-di-tert-butyl-9H-carbazole-9-yl)butyl]phosphoric acid, [6-(3,6-di-tert-butyl-9H-carbazole-9-yl)hexyl]phosphoric acid, [6-(3,6-di-tertAt least one of the following: [6-diphenyl-9H-carbazole-9-yl)hexyl]phosphoric acid, [8-(3,6-diphenyl-9H-carbazole-9-yl)octyl]phosphoric acid, [2-(10H-phenoxazine-10-yl)ethyl]phosphoric acid, [4-(3,7-dibromo-10H-phenthiazine-10-yl)butyl]phosphoric acid, and [4-(3,7-dibromo-10H-phenoxazine-10-yl)butyl]phosphoric acid.

[0076] In some embodiments, the coating includes at least one of spin coating, blade coating, slot coating, and inkjet printing;

[0077] And / or, the annealing conditions are: annealing temperature of 70℃-90℃, such as 70℃, 75℃, 80℃, 85℃, 90℃, etc.; annealing time of 5min-20min, such as 5min, 10min, 15min, 20min, etc.

[0078] A second aspect of this application provides a hole transport layer prepared by the preparation method described in the first aspect.

[0079] A third aspect of this application provides a perovskite solar cell including the hole transport layer described in the second aspect.

[0080] In some embodiments, the perovskite solar cell includes a substrate, a hole transport layer, a perovskite layer, an electron transport layer, a buffer layer, and a back electrode stacked together.

[0081] In one specific example, the substrate includes at least one of an FTO substrate and an ITO substrate.

[0082] In one specific example, the material of the perovskite layer includes perovskite.

[0083] In a specific example, the general formula of the perovskite is AB(X n Y 1-n )3, where A is a monovalent cation, B is a divalent metal ion, X and Y are each an halogen anion independently, and 0≤n≤1.

[0084] In one specific example, the electron transport layer is an n-type semiconductor.

[0085] In one specific example, the material of the electron transport layer includes C60 and / or PCBM.

[0086] In one specific example, the material of the buffer layer includes ALD SnO2 and / or BCP.

[0087] In one specific example, the electrode material includes at least one of ITO, IZO, and Cu.

[0088] A fourth aspect of this application provides an electrical device comprising the perovskite solar cell described in the third aspect.

[0089] Unless otherwise specified, the raw materials used in the following experiments can be purchased from the market.

[0090] The following are specific examples.

[0091] Example 1

[0092] Fabrication of hole transport layer and perovskite solar cell module:

[0093] The specific steps are as follows:

[0094] 1. Substrate Preparation: The FTO layer was scribed using a 1064 nm nanosecond laser. The laser scanned along the preset tandem pattern direction, etching through the FTO and extending to the glass substrate to obtain insulating trenches. The P1 trench linewidth was set to 70 μm, and the width of adjacent cell strips was set to 6 mm, dividing the substrate into 8 tandem sub-cells. The FTO substrate (large-size substrate, 100 mm × 100 mm) was ultrasonically cleaned with deionized water, ethanol, and acetone for 10 min each, then dried. It was then treated with UV-O3 (UV-O3 cleaning machine, air atmosphere, standard low-pressure mercury lamp) for 5 min to enhance hydrophilicity and hydroxyl density, resulting in a treated FTO substrate.

[0095] 2. Preparation of the hole transport layer:

[0096] 1) Preparation of hole transport layer precursor solution: The self-assembled monolayer material SAM is [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), and the composite solvent is triethylene glycol (TEG) and ethanol in a volume ratio of 1:9. The self-assembled monolayer material SAM and the composite solvent are mixed to prepare a hole transport layer precursor solution with a molar concentration of 0.5 mM of MeO-2PACz.

[0097] 2) Preparation of self-assembled monolayer semi-dry films:

[0098] A hole transport layer precursor solution was coated onto the prepared FTO substrate and allowed to stand naturally at room temperature for 30 seconds to form a self-assembled monolayer semi-dry film.

[0099] 3) Electric Field Treatment: Using an FTO substrate as the lower electrode and a Pt sheet as the upper electrode, with back-side wiring, the Pt sheet is placed parallel to the FTO substrate above the self-assembled monolayer semi-dry film. A 200μm polyimide spacer is used to support the upper and lower electrodes, maintaining a 200μm distance between them. A 20V DC voltage (electric field strength 1×10⁻⁶) is applied. 5After maintaining the electric field for 1 minute, the power was turned off and the fixture was removed to obtain a self-assembled monolayer film after electric field treatment.

[0100] 4) Post-processing: After the self-assembled monolayer film treated by electric field is desolventized under vacuum, it is thermally annealed at 80°C for 10 min to form a hole transport layer (thickness of 1.2 nm).

[0101] 3. Preparation of the perovskite layer: Prepare a 1.3 M Cs solution. 0.05 FA 0.95 The PbI3 perovskite precursor solution was prepared using a mixed solvent of N,N-dimethylformamide (DMF) and N-methylpyrrolidone (NMP) in a volume ratio of 8:1.

[0102] The perovskite precursor solution was continuously coated on the surface of the hole transport layer using a slit coating method. The liquid gap of the slit coating head was set to 100 μm and the coating speed was set to 15 mm / s to form a perovskite wet film that uniformly covers each strip and the P1 region, thus obtaining a substrate containing the perovskite wet film.

[0103] After coating, the substrate containing the perovskite wet film was transferred to a vacuum chamber (VCD device) within 5 seconds. The pressure inside the chamber was reduced to 20 Pa within 5 seconds and maintained at 20 Pa for 20 seconds, allowing the DMF and NMP in the perovskite wet film to rapidly partially volatilize and form a uniform mesophase precursor film. Subsequently, the chamber was slowly restored to atmospheric pressure by filling with nitrogen. The substrate containing the mesophase precursor film was then removed and annealed on a hot plate at 150°C for 10 minutes to complete the perovskite crystallization, resulting in a dense, uniformly grained Cs. 0.05 FA 0.95 The PbI3 perovskite layer has a thickness of 500 nm.

[0104] 4. Preparation of electron transport layer: C60 25nm and BCP 8nm are vacuum thermally deposited on the surface of the perovskite layer as electron transport layer. The above stack is scribed with P2 line on one side of the P1 trench using a nanosecond 532 nm UV laser. The P2 line width is set to 80 μm. The etching is carried out along the strip direction until the FTO of the adjacent strip below is exposed, so as to realize the series interconnection contact between the Au top electrode and the FTO of the strip.

[0105] 5. Fabrication of the top electrode: Subsequently, Au 80nm is deposited on the surface of the electron transport layer as the top electrode. Then, the above-mentioned laser source is used to scribing P3, with the P3 line width set to 80μm. The Au top electrode and the upper functional layer are etched away to make the top electrodes of adjacent units insulated from each other, thereby forming a series structure composed of three scribing lines P1-P2-P3, and completing the encapsulation of the perovskite solar cell module.

[0106] Example 2

[0107] Except for adjusting the voltage to 50V (electric field strength of 5×10) 5 Except for V / m), the rest is the same as in Example 1.

[0108] Example 3

[0109] In addition to applying a 20V DC voltage (electric field strength of 1×10), 5 Except for maintaining the V / m for 5 minutes, the rest is the same as in Example 1.

[0110] Example 4

[0111] Except for the hole transport layer thickness of 3 nm, the use of triethylene glycol and ethanol in a volume ratio of 5:5 as composite solvents, the molar concentration of the hole transport layer precursor solution of 1 mM, and the spacing between the upper and lower electrodes of 300 μm, the rest is the same as in Example 1.

[0112] Example 5

[0113] Except for the hole transport layer thickness of 0.8 nm, the use of N-methylpyrrolidone (NMP) and methanol in a volume ratio of 2:8 as a composite solvent, the molar concentration of the hole transport layer precursor solution of 0.1 mM, and the spacing between the upper and lower electrodes of 100 μm, the rest is the same as in Example 1.

[0114] Example 6

[0115] Except for the use of triethylene glycol methyl ether instead of triethylene glycol, the rest is the same as in Example 1.

[0116] Comparative Example 1

[0117] Except for not using electric field treatment, i.e. omitting step 3) in step 2, the rest is the same as in Example 1.

[0118] Comparative Example 2

[0119] Except for the use of ethanol instead of the composite solvent, the rest is the same as in Example 1.

[0120] Comparative Example 3

[0121] Except for the use of triethylene glycol instead of the composite solvent, the rest is the same as in Example 1.

[0122] Comparative Example 4

[0123] Except for a voltage of 10V (electric field strength of 0.5×10⁻⁶). 5 Except for V / m), the rest is the same as in Example 1.

[0124] Comparative Example 5

[0125] Except for a voltage of 180 V (electric field strength of 9 × 10⁻⁶) 5 Except for V / m), the rest is the same as in Example 1.

[0126] Test case

[0127] 1. RMS roughness test of hole transport layer:

[0128] Using an ITO substrate, a hole transport layer was prepared on the ITO substrate according to steps 1-2 in the examples and comparative examples. Using the ITO substrate containing the hole transport layer as a sample, the Ψ and Δ values ​​on the hole transport layer side were measured using a spectroscopic ellipsometry. Then, the following model was established in the analysis software: Air / Rough Layer / SAM / ITO Substrate, where the "rough layer" is an equivalent mixed layer (obtained by mixing air and SAM materials) used to represent the surface undulations of the hole transport layer. The fitted equivalent thickness d_rough (nm) was used as the "RMS roughness." The smaller the value, the smoother the hole transport layer, the lower the roughness, and the better the uniformity, as shown in Table 1. It can be seen that the hole transport layer of the sample prepared according to the examples has a lower RMS roughness than the sample prepared according to the comparative examples. Therefore, the examples can obtain a hole transport layer with better smoothness and lower roughness.

[0129] Simultaneously, using the aforementioned ITO substrate containing a hole transport layer as a sample, a field emission SEM top view was obtained, with an accelerating voltage of 5kV and a magnification of 50,000x. The acquired SEM top view was imported into the image analysis software ImageJ to analyze the equivalent roughness. The more dramatic the grayscale fluctuations in the SEM image, the greater the equivalent roughness; the more uniform the grayscale, the smaller the equivalent roughness. The SEM image of the ITO substrate containing a hole transport layer prepared according to Example 1 is shown below. Figure 2 As can be seen, the hole transport layer is relatively continuous and uniform, with smooth grain boundaries and virtually no obvious pores, cracks, or large aggregates. The SEM image of the ITO substrate containing the hole transport layer prepared according to Comparative Example 1 is shown below. Figure 3 As can be seen, there is uneven brightness and dark areas, island-like clusters, insufficient coverage in some areas, and more interface undulations and defects. Therefore, from... Figure 2-3 It can be clearly seen that the hole transport layer of the sample prepared according to Example 1 is more continuous, uniform and flat, and has a higher coverage of the substrate.

[0130] 2. The open-circuit voltage (Voc), current (Isc), fill factor (FF), and initial photoelectric conversion efficiency (PCE) of the perovskite solar cell modules prepared in the examples and comparative examples were tested using a solar simulator and a Keithley 2400 source meter. The results are shown in Table 1.

[0131] Table 1 Summary of parameters and performance of examples and comparative examples

[0132]

[0133] As shown in Table 1, this application uses a first solvent with a boiling point of 200℃-300℃ and an alcohol solvent with a boiling point of 55℃-85℃ as the composite solvent for the hole transport layer. By applying an electric field of specific intensity perpendicular to the substrate and extending along the semi-dry film direction while maintaining a semi-dry film state, the orientation of SAM molecules can be controlled from top to bottom, improving the continuity and uniformity of the hole transport layer, effectively increasing the coverage of SAM molecules on the substrate, and achieving the fabrication of a high-quality, ultra-thin hole transport layer, which is beneficial for improving the photoelectric conversion efficiency of the device. Furthermore, the fabrication method of this application is simple, reproducible, and suitable for industrial production.

[0134] Comparing Example 1 and Comparative Example 1, it can be seen that the application of a vertical electric field can significantly improve the uniformity of the hole transport layer and significantly improve the light conversion efficiency of the perovskite solar cell.

[0135] Comparing Example 1 and Comparative Examples 2-5, it can be seen that using a composite solvent is more beneficial to improving uniformity than using a single solvent. Furthermore, the strength of the electric field has a significant impact on promoting SAM molecular orientation and improving the uniformity of the hole transport layer. Using a composite solvent under a specific electric field is beneficial to improving the uniformity of the hole transport layer and thus improving the light conversion efficiency of perovskite solar cells.

[0136] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0137] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a hole transport layer, characterized in that, Includes the following steps: A hole transport layer precursor solution containing a self-assembled monolayer material and a composite solvent is coated onto a substrate to prepare a self-assembled monolayer semi-dry film with a solvent content of 99wt%-99.98wt%; the composite solvent includes a first solvent with a boiling point of 200℃-300℃ and an alcohol solvent with a boiling point of 55℃-85℃. The self-assembled monolayer semi-dry film is subjected to electric field treatment to prepare an electric field-treated self-assembled monolayer thin film; the direction of the electric field is perpendicular to the substrate and extends along the direction of the self-assembled monolayer semi-dry film away from the substrate; the strength of the electric field is 1×10⁻⁶. 5 V / m-5×10 5 V / m; The solvent is removed from the self-assembled monolayer film after electric field treatment and annealed to form the hole transport layer.

2. The method for preparing the hole transport layer as described in claim 1, characterized in that, The steps of preparing a self-assembled monolayer semi-dry film by placing the self-assembled monolayer semi-dry film in an electric field for electric field treatment include: using the substrate as the lower electrode connected to the positive electrode and setting the upper electrode connected to the negative electrode, placing the upper electrode above the self-assembled monolayer semi-dry film in a manner parallel to the substrate, applying a voltage to form an electric field, and subjecting the self-assembled monolayer semi-dry film to electric field treatment to prepare a self-assembled monolayer film after electric field treatment.

3. The method for preparing the hole transport layer as described in claim 2, characterized in that, It meets one or more of the following characteristics: (1) The voltage is 20V-100V; (2) The electric field treatment time is 1 min to 5 min; (3) The substrate includes at least one of ITO substrate and FTO substrate; (4) The upper electrode includes at least one of a platinum electrode, a carbon-based electrode, and gold-plated glass; (5) The distance between the upper electrode and the lower electrode is 100μm-300μm; (6) The thickness of the hole transport layer is 0.8nm-3nm.

4. The method for preparing the hole transport layer according to any one of claims 1-3, characterized in that, It meets one or more of the following characteristics: (1) In the composite solvent, the volume ratio of the first solvent to the alcohol solvent is 1:9-5:5; (2) The first solvent includes at least one of triethylene glycol, N-methylpyrrolidone and triethylene glycol methyl ether; (3) The alcohol solvent includes at least one of methanol and ethanol; (4) In the hole transport layer precursor solution, the molar concentration of the self-assembled monolayer material is 0.1 mM-1 mM.

5. The method for preparing a hole transport layer according to any one of claims 1-3, characterized in that, The self-assembled monolayer material includes [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, [3-(3,6-dimethoxy-9H-carbazole-9-yl)propyl]phosphonic acid, [6-(3,6-dimethoxy-9H-carbazole-9-yl)hexyl]phosphonic acid, [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphonic acid, [3-(3,6-dimethyl-9H-carbazole-9-yl)propyl]phosphonic acid, [6-(3,6-dimethyl-9H-carbazole-9-yl)hexyl]phosphonic acid, [1-(3,6-dimethyl-9H-carbazole-9-yl)methyl]phosphonic acid, [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid, [8-(3 [6-Dimethyl-9H-carbazole-9-yl)octyl]phosphate, [1-(9H-carbazole-9-yl)methyl]phosphate, (2-(9H-carbazole-9-yl)ethyl)phosphate, [3-(9H-carbazole-9-yl)propyl]phosphate, [4-(9H-carbazole-9-yl)butyl]phosphate, [6-(9H-carbazole-9-yl)hexyl]phosphate, [8-(9H-carbazole-9-yl)octyl]phosphate, [4-(N,N-di(4-methoxyphenylamino)phenyl)propyl]phosphate, 2,3,4,5,6-pentafluorobenzyl phosphate, [2-(9H-9'-phenyl-3,3'-dicarbazole-9-yl)ethyl]phosphate, [4-(9H-9'-phenyl-3,3'-dicarbazole-9-yl)ethyl]phosphate, [4-(9H-9'-phenyl-3,3'-dicarbazole-9-yl)ethyl]phosphate, [4-(9H-9'-phenyl-3,3'-dicarbazole-9-yl)ethyl]phosphate, [6 ... [9-yl)butyl]phosphoric acid, [4-(diphenylamino)phenyl)ethyl]phosphoric acid, [4-(diphenylamino)phenyl)propyl]phosphoric acid, [4-(10H-phenthiazin-10-yl)butyl]phosphoric acid, [2-(7H-dibenzocarbazole-7-yl)ethyl]phosphoric acid, [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid, [3-(3,6-dibromo-9H-carbazole-9-yl)propyl]phosphoric acid, [4-(3,6-dibromo-9H-carbazole-9-yl)butyl]phosphoric acid, [6-(3,6-dibromo-9H-carbazole-9-yl)hexyl]phosphoric acid, [1-(3,6-di-tert-butyl-9H-carbazole-9-yl)methyl]phosphoric acid, [2 ...3,6-di-tert-butyl-9H-carbazole-9-yl)propyl]phosphoric acid, [4-(10H-phenthiazin-10-yl)butyl]phosphoric acid, [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid, [3-(3,6-di-tert-butyl-9H-carbazole-9-yl)propyl]phosphoric acid, [4-(10H-phenthiazin-10-yl)butyl]phosphoric acid, [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid, [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid, [4-(7H-dibenzocarbazole- [3-(3,6-di-tert-butyl-9H-carbazole-9-yl)propyl]phosphate, [4-(3,6-di-tert-butyl-9H-carbazole-9-yl)butyl]phosphate, [6-(3,6-di-tert-butyl-9H-carbazole-9-yl)hexyl]phosphate, [8-(3,6-di-tert-butyl-9H-carbazole-9-yl)octyl]phosphate, [1-(3,6-diphenyl-9H-carbazole-9-yl)methyl]phosphate, [2-(3,6-diphenyl-9H-carbazole-9-yl)ethyl]phosphate, [3-(3,6-diphenyl-9H-carbazole-9-yl)propyl]phosphate, [4-(3,6-diphenyl ...phenyl-9H-carbazole-9-yl)ethyl]phosphate, [6-(3,6-diphenyl-9H-carbazole-9-yl)hexyl]phosphate, [6-(3,6-diphenyl-9H-carbazole-9-yl)ethyl]phosphate, [3-(3,6-diphenyl-9H-carbazole-9-yl)propyl]phosphate, [4-(3,6-diAt least one of the following: [6-diphenyl-9H-carbazole-9-yl)hexyl]phosphoric acid, [8-(3,6-diphenyl-9H-carbazole-9-yl)octyl]phosphoric acid, [2-(10H-phenoxazine-10-yl)ethyl]phosphoric acid, [4-(3,7-dibromo-10H-phenthiazine-10-yl)butyl]phosphoric acid, and [4-(3,7-dibromo-10H-phenoxazine-10-yl)butyl]phosphoric acid.

6. The method for preparing a hole transport layer according to any one of claims 1-3, characterized in that, The coating includes at least one of spin coating, blade coating, slot coating and inkjet printing; And / or, the annealing conditions are: annealing temperature of 70℃-90℃; annealing time of 5min-20min.

7. The hole transport layer prepared by the method for preparing a hole transport layer according to any one of claims 1-6.

8. A perovskite solar cell, characterized in that, Includes the hole transport layer as described in claim 7.

9. The perovskite solar cell as described in claim 8, characterized in that, The perovskite solar cell includes a substrate, a hole transport layer, a perovskite layer, an electron transport layer, a buffer layer, and a back electrode, all stacked together.

10. An electrical device, characterized in that, Including the perovskite solar cell of claim 9.

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