Hole transport layer, preparation method thereof and perovskite device

Abstract

The invention provides a hole transport layer, a preparation method thereof and a perovskite device, and belongs to the field of semiconductors, and the preparation method of the hole transport layer comprises the steps: providing a substrate, and placing the substrate in an atomic layer deposition reaction chamber; and alternately inputting a gaseous nickel precursor and gaseous water into the reaction chamber in a pulse manner, depositing on the surface of the substrate to form a film, and alternately operating for multiple times until the film reaches a preset thickness to obtain the hole transport layer. According to the technical scheme, the NiOx hole transport layer is prepared by using the atomic layer deposition process, so that the optical and electrical properties and the interface behavior of the NiOx hole transport layer can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, in particular to a hole transport layer, a preparation method thereof and a perovskite device. BACKGROUND

[0002] Under the driving of global energy structure transformation and "double carbon" target, renewable energy replacing fossil energy has become an inevitable trend. As the most widely distributed and abundant renewable energy, solar energy has attracted much attention. Perovskite solar cells have become one of the research hotspots in the field of new energy due to their high photoelectric conversion efficiency, low preparation cost, flexibility and other outstanding advantages.

[0003] As a kind of all-inorganic perovskite compound, CsPbBr3 perovskite material has more excellent thermal stability and chemical stability compared with the most widely used commercial organic-inorganic hybrid perovskite material, has great application potential in harsh environments such as high temperature and high humidity, and can effectively solve the degradation problem during long-term use of the device. At the same time, the hole transport layer is also an important part of the perovskite solar cell, which determines the service life and performance of the cell. However, the most commonly used Spiro-OMeTAD hole transport layer has the disadvantages of insufficient stability and complex preparation process. Therefore, it is urgent to seek a more suitable hole transport material.

[0004] NiO x As an inorganic p-type semiconductor material, it has the advantages of suitable band gap (about 3.5eV), high hole mobility, good chemical stability, and energy level matching with CsPbBr3 perovskite layer, which is undoubtedly the most ideal hole transport material. The existing NiO x The preparation methods of the hole transport layer mainly include magnetron sputtering, sol-gel method, electron beam evaporation, etc., but all have different degrees of limitations. The magnetron sputtering method usually relies on high-power vacuum equipment, not only the preparation cost is high, but also ion bombardment and thermal effects are easy to occur during deposition, which is not compatible with flexible or low-heat-resistant substrates; the sol-gel method is simple to operate, but often needs high-temperature annealing to realize NiO x crystallization, which not only increases the energy consumption, but also easily causes micro-cracks and pores in the film, reducing the denseness and stability of the film; the electron beam evaporation method has problems such as difficulty in accurately controlling the uniformity of the film composition, weak adhesion between the film and the substrate, etc., which is not conducive to the long-term stability and reliability of the device performance. SUMMARY

[0005] In view of the technical problems in the background art, the purpose of the present application is to provide a hole transport layer, a preparation method thereof and a perovskite device, the preparation method of the hole transport layer uses an atomic layer deposition process to prepare NiO xThe hole transport layer can improve its optical, electrical and interface behaviors.

[0006] To achieve the above-mentioned purpose, the application provides a preparation method of a hole transport layer, comprising: providing a substrate, and placing the substrate in an atomic layer deposition reaction chamber; alternately and pulsedly inputting gaseous nickel precursor and gaseous water into the reaction chamber to deposit a thin film on the surface of the substrate, and repeatedly operating until the thin film reaches a preset thickness, so as to obtain the hole transport layer.

[0007] Further, the reaction gas flow of the gaseous nickel precursor and / or the gaseous water is 10-30 sccm.

[0008] Further, the gaseous water comprises ultrapure water; and / or, the single pulse time of the gaseous water is 20-60 ms.

[0009] Further, the gaseous nickel precursor comprises bis(N,N'-di-tert-butylacetamidinate) nickel; and / or, the single pulse time of the gaseous nickel precursor is 2-5 s.

[0010] Further, after the pulsed input of the gaseous nickel precursor, the method further comprises introducing inert gas into the reaction chamber for purging; and / or, after the pulsed input of the gaseous water, the method further comprises introducing inert gas into the reaction chamber for purging.

[0011] Further, the inert gas comprises at least one of nitrogen, argon or helium.

[0012] Further, the temperature of the reaction chamber is 150-200℃; and / or, the pressure of the reaction chamber is lower than 0.2 Torr.

[0013] Further, the preparation of the gaseous nickel precursor comprises: heating the solid or liquid nickel precursor to 135-180℃ to vaporize it, and using inert gas carrier gas to transport the gaseous nickel precursor to the reaction chamber.

[0014] To achieve the above-mentioned purpose, the application further provides a hole transport layer prepared by the above-mentioned preparation method of a hole transport layer.

[0015] To achieve the above-mentioned purpose, the application further provides a perovskite device comprising the above-mentioned hole transport layer.

[0016] The technical effects of the application are: The technical scheme of the present application uses water with milder reactivity as a co-reactant to prepare a more uniform and stable NiO film by regulating key process parameters (water pulse time or deposition temperature) x The pulse time of water can regulate the ratio of Ni 3+ / Ni 2+ in the film, so that the overall energy level is lowered, and the energy level of the hole transport layer is fine-tuned to achieve better energy level matching, which helps to achieve higher hole extraction rate at the perovskite light-absorbing layer / NiO x interface. At the same time, the advantages of conformal deposition by atomic layer deposition are fully utilized to precisely control the film thickness, thereby affecting the optical, electrical and interfacial behavior.

[0017] In addition, the preparation method of the hole transport layer adopts an atomic layer deposition process, which alternately inputs gaseous nickel precursor and gaseous water into the reaction chamber to deposit NiO x film on the surface of the substrate. This method can precisely control the film thickness and composition uniformity, does not require high-temperature annealing, reduces energy consumption and avoids film cracking, and improves the density, flatness, stability and adhesion of the hole transport layer to the substrate. The hole transport layer prepared by this method has excellent optical and electrical properties, and when applied to perovskite devices, it can regulate the interface state, reduce the carrier recombination probability at the perovskite / hole transport layer interface, and more efficiently extract holes, thereby enhancing the photoelectric conversion efficiency and long-term stability of the device. The present application provides a new and effective way for the preparation of high-performance perovskite devices.

[0018] The above description is only a summary of the technical scheme of the present application. In order to more clearly understand the technical means of the present application, the specific embodiments of the present application can be implemented in accordance with the content of the specification, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following will specifically describe the embodiments of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical scheme of the present application, the drawings used in the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating any creative labor.

[0020] Figure 1 is the J-V curve of Example 1 and Comparative Examples 1-3; Figure 2 is the J-V curve of Example 1, Example 2 and Example 3; Figure 3 is the J-V curve of Example 1, Example 4 and Example 5; Figure 4XPS corresponds to different NiO x Ni2p energy level spectra at (20ms, 40ms, 60ms); Figure 5 NiO deposited at different water pulse times x Hall carrier concentration and mobility of thin films. Detailed Implementation

[0021] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0023] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0026] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0027] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0028] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0029] NiO x As an inorganic p-type semiconductor material, NiO possesses advantages such as a suitable bandgap (approximately 3.5 eV), high hole mobility, good chemical stability, and energy level matching with CsPbBr3 perovskite layers, making it undoubtedly the most ideal hole transport material. x The main methods for preparing hole transport layers include magnetron sputtering, sol-gel methods, and electron beam evaporation, but each has its limitations. Magnetron sputtering typically relies on high-power vacuum equipment, resulting in high preparation costs and the potential for ion bombardment and thermal effects during deposition, making it incompatible with flexible or low-heat-resistant substrates. While the sol-gel method is simple to operate, it often requires high-temperature annealing to achieve NiO. x Crystallization not only increases energy consumption but also easily causes microcracks and pores in the thin film, reducing its density and stability. Electron beam evaporation has problems such as difficulty in precisely controlling the uniformity of thin film composition and weak adhesion between the thin film and the substrate, which are detrimental to the long-term stability and reliability of device performance.

[0030] To achieve the above objectives, this invention proposes a method for preparing a hole transport layer, comprising: Provide a substrate and place it in the atomic layer deposition reaction chamber; Gaseous nickel precursor and gaseous water are alternately pulsed into the reaction chamber to deposit a thin film on the substrate surface. This process is repeated multiple times until the film reaches a preset thickness, thus obtaining a hole transport layer.

[0031] The technical solution of this invention utilizes water, which has a milder reactivity, as a co-reactant. By controlling key process parameters (water pulse time or deposition temperature), more uniform and stable NiO can be prepared. x Thin film. The pulse timing of the water can be used to modulate the Ni content in the thin film. 3+ / Ni 2+ The ratio of [specific energy level] causes the overall energy level to decrease, while the energy level of the hole transport layer can be fine-tuned to achieve better energy level matching, which helps in the interaction between the perovskite light-absorbing layer and NiO. x The interface achieves a higher hole extraction rate. At the same time, it fully utilizes the advantages of conformal deposition in atomic layer deposition to precisely control the film thickness, thereby affecting its optical and electrical properties and interface behavior.

[0032] Understandably, the substrate can be prepared in various ways. For example, an 80nm-150nm thick indium tin oxide or fluorine-doped tin oxide conductive film can be deposited on the surface of transparent conductive glass (such as ITO or FTO glass) using magnetron sputtering as the conductive layer. Flexible substrates (such as PET or PEN) can also be used, but a conductive layer needs to be pre-prepared on their surface. Before placing the substrate in the atomic layer deposition chamber, it is usually cleaned to remove impurities such as oil, dust, and organic residues, ensuring a clean surface and improving the subsequent deposition of NiO. x The adhesion and interface quality between the film and the substrate. During cleaning, ultrasonically clean with solvents such as deionized water, acetone, and isopropanol for 10-20 minutes in sequence. After cleaning, dry with nitrogen or in a vacuum drying oven for later use.

[0033] Furthermore, the reaction gas flow rate for the gaseous nickel precursor and / or gaseous water is 10 sccm-30 sccm.

[0034] In this embodiment, by controlling the reaction gas flow rate of gaseous nickel precursor and / or gaseous water within the range of 10 sccm-30 sccm, effective regulation of the reactant concentration and diffusion behavior within the reaction chamber can be achieved. When the gas flow rate is too low, the supply of precursor or water molecules within the reaction chamber is insufficient, leading not only to a slow deposition rate and reduced production efficiency, but also potentially making it difficult to form a continuous and uniform film due to insufficient reactant supply. Conversely, when the gas flow rate is too high, it may cause excessively high local reactant concentrations within the reaction chamber, resulting in uneven nucleation and growth, leading to a rough film surface and even defects such as pinholes and agglomerations, thereby affecting the electrical and optical properties of the hole transport layer. Within this optimized range, uniform coverage and sufficient reaction can be achieved on the deposition surface, providing a basis for preparing high-quality, highly uniform NiO. x Thin films provide a stable process window.

[0035] Furthermore, gaseous water includes ultrapure water.

[0036] In this embodiment, ultrapure water is used as the oxygen source, which can minimize the interference of dissolved impurity ions (such as sodium, calcium, and magnesium ions) on the deposition reaction. If these impurity ions are present, they may embed NiO during the film growth process. x Lattice or adsorption on the film surface causes the film's stoichiometry to deviate from the ideal value, affecting its conductivity and hole mobility. The high purity of ultrapure water ensures the cleanliness of the reaction system, contributing to the formation of NiO with a purer chemical composition and more regular structure. x Thin film, thereby improving the overall performance of hole transport layer.

[0037] Furthermore, the single pulse duration of gaseous water is 20ms-60ms.

[0038] In this embodiment, by setting the single pulse time of gaseous water to 20ms-60ms, the processing of NiO can be achieved. x Precise control of thin film chemical composition and microstructure. Water pulse time is used to regulate Ni content in thin films. 3+ / Ni 2+ Key factors in the ratio: When the water pulse time is at the lower limit of this range (e.g., about 20ms), the supplied water molecular weight is moderate, the degree of oxidation is limited, and Ni in the film mainly exists as Ni. 2+ The valence state exists; and as the pulse time is extended to the upper limit (e.g., increased to 60ms), water molecules participate in the reaction more fully, providing more oxygen source, thus enabling Ni to... 2+ Further oxidized to Ni 3+ This enables the observation of Ni in the thin film. 3+ / Ni 2+ The proportion is gradually and controllably increased. Ni 3+ As a crucial source of charge carriers, increasing its proportion helps improve the hole concentration and conductivity of the thin film. By precisely controlling the water pulse time within the range of 20ms-60ms, a sufficient and uniform reaction between water and the nickel precursor adsorbed on the substrate surface can be ensured, achieving an optimal balance between film stoichiometry and crystallinity. This control enables NiO... x The chemical valence ratio of the thin film can be optimized in a targeted manner, thereby achieving fine adjustment of its energy level structure to better match the energy level of the perovskite light-absorbing layer and effectively improve the hole extraction efficiency at the interface.

[0039] Furthermore, the gaseous nickel precursor includes di(N,N'-di-tert-butylacetamidine)nickel.

[0040] In this embodiment, di(N,N'-di-tert-butylacetamidine)nickel is used as the nickel precursor due to its excellent thermal stability and chemical activity. This precursor, in either solid or liquid state, can be stably vaporized by heating to a temperature range of 135°C-180°C, forming easily transportable gaseous molecules. The amidine ligands in its molecular structure form stable coordination bonds with the nickel center, allowing the precursor to be uniformly adsorbed onto the substrate surface as a monolayer during atomic layer deposition, without easily decomposing or agglomerating. This characteristic ensures that an ordered, self-limiting chemical reaction can occur on the substrate surface during alternating pulsed reactions with gaseous water, thereby precisely controlling the NiO reaction. x Thin film growth ensures uniformity of thickness and consistency of composition. Simultaneously, the decomposition products of this precursor are mainly small organic molecules, easily removed by inert gas purging, minimizing adverse effects on film quality and paving the way for the preparation of high-performance NiO. x The hole transport layer provides a reliable material basis.

[0041] Furthermore, the single pulse duration of the gaseous nickel precursor is 2s-5s.

[0042] In this embodiment, the single pulse duration of the gaseous nickel precursor is set to 2-5 seconds, allowing the precursor molecules to fully diffuse within the cavity and react with the active sites on the substrate surface, achieving surface saturation coverage dominated by chemisorption. This process ensures that the precursor can form a monolayer adsorption, providing sufficient reaction sites for subsequent alternating pulse reactions with water, thereby stably achieving self-limiting growth.

[0043] Furthermore, after the pulse input of the gaseous nickel precursor, the reaction chamber is also purged by introducing an inert gas.

[0044] In this embodiment, by continuously introducing inert gas, excess gaseous nickel precursor molecules that have not been adsorbed onto the substrate surface and any potential byproducts can be completely removed from the reaction chamber. This prevents unreacted precursor residues from interfering with the subsequent water pulse stage reaction and avoids cross-contamination between different pulse cycles. This operation ensures that each nickel precursor pulse forms only a saturated adsorption layer on the substrate surface, making the subsequent chemical reaction with water strictly limited to the surface-adsorbed precursor molecules. This allows for the controllable, layer-by-layer deposition of NiO with single-atom-layer precision. x The thin film ensures the accuracy of the film thickness and the consistency between batches.

[0045] Furthermore, after the pulsed input of gaseous water, the reaction chamber is also purged by introducing inert gas.

[0046] In this embodiment, the inert gas purging step effectively removes residual water molecules and reaction byproducts from the reaction chamber, ensuring the self-limiting surface reaction mechanism of atomic layer deposition. This step maintains the cleanliness and activity consistency of the reaction surface, effectively ensuring the independence and precision of each deposition cycle, thereby obtaining NiO with controllable composition, uniform thickness, smooth surface, and stable electrical properties. x The thin film provides an ideal surface condition for subsequent deposition cycles.

[0047] Furthermore, the inert gas includes at least one of nitrogen, argon, or helium.

[0048] In this embodiment, inert gases such as nitrogen, argon, or helium are chosen as purge gases because they are chemically stable and do not react with any components in the reaction system. Nitrogen, as a low-cost and readily available inert gas, effectively controls process costs while ensuring purging effectiveness. Argon, with its large molecular weight and high density, has a stronger ability to carry residual gases, resulting in higher purging efficiency and making it suitable for deposition scenarios with more stringent cleanliness requirements. Helium, with its small molecular weight and fast diffusion rate, can quickly penetrate into the tiny gaps in the reaction chamber, ensuring thorough purging without dead zones. In practical applications, a single inert gas or a mixture of multiple inert gases can be selected based on specific process requirements (such as purity requirements, equipment conditions, and cost control targets) to achieve the best purging effect and further ensure the purity of NiO. x Precise controllability of the thin film deposition process and stability of thin film quality.

[0049] Furthermore, the temperature of the reaction chamber is 150℃-200℃.

[0050] In this embodiment, controlling the temperature of the reaction chamber within the range of 150℃-200℃ is one of the key parameters to ensure that the nickel-based precursor and the oxygen source precursor can react fully and obtain a uniformly structured nickel oxide film. This temperature range allows the nickel precursor to be stably adsorbed on the substrate surface and participate in the subsequent oxygen source reaction, thereby obtaining a uniform and dense nickel oxide film.

[0051] Furthermore, the pressure in the reaction chamber is below 0.2 Torr.

[0052] In this embodiment, by controlling the pressure in the reaction chamber to a vacuum environment below 0.2 Torr, the interference of residual gas molecules (such as oxygen, water vapor, carbon dioxide, etc.) on the deposition process can be significantly reduced. Lowering the working pressure of the reaction chamber helps improve the transport efficiency of the nickel precursor to the substrate surface and promotes the outflow of byproducts and unreacted components, thereby obtaining a nickel oxide film with a clean interface and uniform structure. A working pressure below 0.2 Torr helps improve the precursor exchange efficiency and reduce the secondary adhesion of residual molecules, thus maintaining the self-limited growth characteristics of atomic layer deposition and achieving controllable deposition of film thickness and composition.

[0053] Further, the preparation of the gaseous nickel precursor includes: Solid or liquid nickel precursors are heated to 135°C-180°C to vaporize them, and an inert carrier gas is used to transport the gaseous nickel precursors to the reaction chamber.

[0054] In this embodiment, a solid or liquid nickel precursor (such as bis(N,N'-di-tert-butylacetamidine)nickel) is heated to a temperature range of 135°C-180°C, causing it to overcome intermolecular forces and transform into a gaseous state. This temperature range is chosen based on the saturated vapor pressure characteristics of the nickel precursor: at this temperature, the precursor can generate sufficient vapor pressure to form a stable gaseous molecular flow, while avoiding thermal decomposition or chemical structural damage due to excessively high temperatures. An inert gas (such as nitrogen or argon) is used as the carrier gas, utilizing its chemical inertness to avoid reaction with the gaseous nickel precursor and ensure that the precursor is delivered to the reaction chamber in a pure state. The carrier gas carries the gaseous nickel precursor at a stable flow rate (e.g., 10 sccm-30 sccm) through a dedicated gas pipeline system into the atomic layer deposition reaction chamber, providing a continuous and controllable supply of precursor for subsequent adsorption and reaction on the substrate surface.

[0055] To achieve the above objectives, the present invention also proposes a hole transport layer, which is prepared by the above-described method for preparing a hole transport layer. This hole transport layer possesses all the beneficial effects of the method described above, and will not be elaborated further here.

[0056] To achieve the above objectives, the present invention also proposes a perovskite device including the aforementioned hole transport layer. This perovskite device possesses all the beneficial effects of the aforementioned hole transport layer, which will not be elaborated further here.

[0057] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0058] I. Preparation Method Example 1 (1) The blank FTO glass substrate was ultrasonically cleaned for 20 minutes with cleaning agent, ultrapure water and anhydrous ethanol in sequence, dried and then treated with UV; SnO2 was deposited on the FTO glass substrate by atomic layer deposition, and annealed at 140°C for 30 minutes to form an electron transport layer on the FTO glass substrate. (2) Evaporate 120nm CsBr, 170nm PbBr2, 120nm CsBr and 170nm PbBr2 sequentially on the sample in step (1) at a deposition rate of 5μm / s. Then heat up to 320℃ for 20min and hold for 20min. Then cool down to 300℃ for 5min and hold for 40min. Then cool down naturally to 100℃ to prepare a perovskite film. (3) PEABr was dissolved in IPA at a concentration of 1.5 mg / mL, and then prepared by ultrasonic spraying. After annealing at 70°C for 10 min, a passivation layer was formed to obtain the substrate. (4) Place the substrate into an atomic layer deposition reaction chamber preheated to 180°C for 1 hour to perform NiO deposition. x Hole transport layer deposition: The chamber vacuum level is below 0.2 Torr. Gaseous nickel precursor and gaseous water are alternately pulsed into the reaction chamber to deposit a thin film on the substrate surface. This alternating process is repeated until the film reaches the preset thickness, thus obtaining the hole transport layer. The nickel precursor used is di(N,N'-di-tert-butylacetamidine)nickel, and the gaseous water is ultrapure water. The reaction gas flow rate is 20 sccm. The nickel precursor is maintained at 135°C to ensure sufficient vapor pressure and is transported using N2 via a delivery line heated to 150°C. In one cycle, the pulse duration of the gaseous nickel precursor is 3 s followed by 3 s exposure and 30 s nitrogen purging; the pulse duration of the gaseous water is 40 ms followed by 3 s exposure and 30 s nitrogen purging. After 60 cycles, NiO is prepared. x Hole transport layer.

[0059] (5) A 20 nm thick ITO electrode was prepared on the hole transport layer by magnetron sputtering and annealed at 250 °C for 5 min to obtain the perovskite device of Example 1.

[0060] Example 2 The difference from Example 1 is that the pulse time of the gaseous water is 20ms. The remaining steps are roughly the same as in Example 1 and will not be described in detail here, thus obtaining the perovskite device of Example 2.

[0061] Example 3 The difference from Example 1 is that the pulse time of the gaseous water is 60ms. The remaining steps are roughly the same as in Example 1 and will not be described in detail here, thus obtaining the perovskite device of Example 3.

[0062] Example 4 The difference from Example 1 is that the temperature of the reaction chamber is 160°C. The remaining steps are roughly the same as in Example 1 and will not be described in detail here, thus obtaining the perovskite device of Example 4.

[0063] Example 5 The difference from Example 1 is that the temperature of the reaction chamber is 200°C. The remaining steps are roughly the same as in Example 1 and will not be described in detail here, thus obtaining the perovskite device of Example 5.

[0064] Comparative Example 1 The difference from Example 1 is that Spiro-OMeTAD is used as the hole transport layer.

[0065] A method for preparing Spiro-OMeTAD as a hole transport layer includes the following steps: (1) The blank FTO glass substrate was ultrasonically cleaned for 20 minutes with cleaning agent, ultrapure water and anhydrous ethanol in sequence, dried and then treated with UV; SnO2 was deposited on the FTO glass substrate by ALD and annealed at 140℃ for 30 minutes to form an electron transport layer on the FTO glass substrate. (2) Evaporate 120nm CsBr, 170nm PbBr2, 120nm CsBr and 170nm PbBr2 sequentially on the sample in step (1) at a deposition rate of 5μm / s. Then heat up to 320℃ for 20min and hold for 20min. Then cool down to 300℃ for 5min and hold for 40min. Then cool down naturally to 100℃ to prepare a perovskite film. (3) PEABr was dissolved in IPA at a concentration of 1.5 mg / mL, and then prepared by ultrasonic spraying. After annealing at 70°C for 10 min, a passivation layer was formed. (4) Spin-coat the Spiro-OMeTAD solution onto the sample from step (3), and anneal it at 80°C for 15 minutes to obtain the hole transport layer; (5) A 20 nm thick ITO electrode was prepared on the hole transport layer by magnetron sputtering and annealed at 250 °C for 5 min to obtain the perovskite device of Comparative Example 1.

[0066] Comparative Example 2 The difference from Example 1 is that PEDOT:PSS is used as the hole transport layer.

[0067] (1) The blank FTO glass substrate was ultrasonically cleaned for 20 minutes with cleaning agent, ultrapure water and anhydrous ethanol in sequence, dried and then treated with UV; SnO2 was deposited on the FTO glass substrate by ALD and annealed at 140℃ for 30 minutes to form an electron transport layer on the FTO glass substrate. (2) Evaporate 120nm CsBr, 170nm PbBr2, 120nm CsBr and 170nm PbBr2 sequentially on the sample in step (1) at a deposition rate of 5μm / s. Then heat up to 320℃ for 20min and hold for 20min. Then cool down to 300℃ for 5min and hold for 40min. Then cool down naturally to 100℃ to prepare a perovskite film. (3) PEABr was dissolved in IPA at a concentration of 1.5 mg / mL, and then prepared by ultrasonic spraying. After annealing at 70°C for 10 min, a passivation layer was formed. (4) Then spin-coat PEDOT:PSS onto the sample from step (3), anneal at 120°C for 30 min, and obtain the hole transport layer after cooling.

[0068] (5) A 20 nm thick ITO electrode was prepared on the hole transport layer by magnetron sputtering and annealed at 250 °C for 5 min to obtain the perovskite device of Comparative Example 2.

[0069] Comparative Example 3 The difference from Example 1 is that CuSCN is used as the hole transport layer.

[0070] (1) The blank FTO glass substrate was ultrasonically cleaned for 20 minutes with cleaning agent, ultrapure water and anhydrous ethanol in sequence, dried and then treated with UV; SnO2 was deposited on the FTO glass substrate by ALD and annealed at 140℃ for 30 minutes to form an electron transport layer on the FTO glass substrate. (2) Evaporate 120nm CsBr, 170nm PbBr2, 120nm CsBr and 170nm PbBr2 sequentially on the sample in step (1) at a deposition rate of 5μm / s. Then heat up to 320℃ for 20min and hold for 20min. Then cool down to 300℃ for 5min and hold for 40min. Then cool down naturally to 100℃ to prepare a perovskite film. (3) PEABr was dissolved in IPA at a concentration of 1.5 mg / mL, and then prepared by ultrasonic spraying. After annealing at 70°C for 10 min, a passivation layer was formed. (4) The CuSCN solution is then spin-coated onto the sample from step (3), annealed at 120°C for 30 min, and cooled to obtain a hole transport layer. The sample is then annealed at 100°C for 10 min and cooled to obtain a hole transport layer.

[0071] (5) A 20 nm thick ITO electrode was prepared on the hole transport layer by magnetron sputtering and annealed at 250 °C for 5 min to obtain the perovskite device of Comparative Example 3.

[0072] II. Testing Methods JV curves were measured using a solar simulator (Oriel 94023A, 300W) and a Keithley 2400 illuminometer. Luminous intensity (100mW / cm²) was calibrated using a standard silicon solar cell (Oriel, the standard for very large-scale integration).

[0073] X-ray photoelectron spectroscopy (XPS) was performed on an X-ray photoelectron spectrometer (ESCALAB250Xi) equipped with an AlKα X-ray source. The test was conducted without air isolation at a temperature of 25°C and a humidity of 40%.

[0074] Hall mobility and carrier concentration were measured on a Hall effect tester (LakeShore M91, USA) with a magnetic field strength of 0.5T and a sample thickness of 100nm. The test was conducted without air isolation at a temperature of 25℃ and a humidity of 40%.

[0075] III. Analysis of Test Results for Each Embodiment and Comparative Example Table 1. Performance test results of perovskite devices in Examples 1-5 and Comparative Examples 1-3. JV curve tests were performed on the perovskite devices prepared in Examples 1-5 and Comparative Examples 1-3, and the results are as follows: Figures 1 to 3 As shown, the open-circuit voltage (V) of the perovskite device was tested. oc ), fill factor (FF), short-circuit current (J) sc ), Battery efficiency (PCE).

[0076] Visit Figures 1 to 3 As shown in Table 1, NiO is used. x The performance of devices acting as hole transport layers is significantly improved, and the short-circuit current (J) is reduced. sc The fill factor (FF) and battery efficiency (PCE) have all been improved to varying degrees.

[0077] Visit Figure 4 It can be seen that NiO was prepared under different water pulse times (i.e., Examples 1-3). x The surface composition of the thin film, NiO, changes with increasing water pulse time.x Surface Ni 3+ / Ni 2+ It shows an increasing trend, Ni 3+ When the NiO content increases x The band gap will continue to decrease.

[0078] Visit Figure 5 According to the Halleffect test results (i.e. Examples 1-3), the carrier concentration increases significantly with the increase of water pulse time. Generally, the increase of carrier concentration will improve mobility. However, at a constant temperature, the increase of carrier concentration will also lead to the enhancement of scattering effect, which will inhibit carrier migration. Therefore, the mobility in the figure shows a trend of first increasing and then decreasing with the increase of carrier concentration.

[0079] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for preparing a hole transport layer, characterized in that, include: A substrate is provided, and the substrate is placed in an atomic layer deposition reaction chamber; Gaseous nickel precursor and gaseous water are alternately pulsed into the reaction chamber to deposit a thin film on the substrate surface. This process is repeated multiple times until the film reaches a preset thickness, thus obtaining a hole transport layer.

2. The method for preparing a hole transport layer according to claim 1, characterized in that, The reaction gas flow rate of the gaseous nickel precursor and / or the gaseous water is 10 sccm-30 sccm.

3. The method for preparing a hole transport layer according to claim 1, characterized in that, The gaseous water includes ultrapure water; and / or, The duration of a single pulse of the gaseous water is 20ms-60ms.

4. The method for preparing a hole transport layer according to claim 1, characterized in that, The gaseous nickel precursor comprises di(N,N'-di-tert-butylacetamidine)nickel; and / or, The single pulse duration of the gaseous nickel precursor is 2s-5s.

5. The method for preparing a hole transport layer according to claim 1, characterized in that, After the pulse input to the gaseous nickel precursor, the process further includes purging the reaction chamber with an inert gas; and / or, After the pulse input of the gaseous water, the process also includes purging the reaction chamber with inert gas.

6. The method for preparing a hole transport layer according to claim 5, characterized in that, The inert gas includes at least one of nitrogen, argon, or helium.

7. The method for preparing a hole transport layer according to claim 1, characterized in that, The temperature of the reaction chamber is 150℃-200℃; and / or, The pressure in the reaction chamber is less than 0.2 Torr.

8. The method for preparing a hole transport layer according to claim 1, characterized in that, The preparation of the gaseous nickel precursor includes: The solid or liquid nickel precursor is heated to 135°C-180°C to vaporize it, and the gaseous nickel precursor is transported to the reaction chamber using an inert carrier gas.

9. A hole transport layer, characterized in that, It is prepared by the method for preparing the hole transport layer according to any one of claims 1 to 8.

10. A perovskite device, characterized in that, Includes the hole transport layer as described in claim 9.

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