A NiO X A / SAM double-layer hole transport layer, preparation method thereof and solar cell

Abstract

The application provides a NiO X / SAM double-layer hole transport layer, a preparation method thereof and a solar cell, and belongs to the technical field of solar cells. The preparation method comprises the following steps: S1. preparing a NiO X thin film on a conductive glass or a crystalline silicon bottom cell by magnetron sputtering; S2. coating a pretreatment liquid on the surface of the NiO X thin film to obtain a pretreated NiO X thin film, wherein the pretreatment liquid is a hydrogen peroxide solution, an acetic acid solution or an alcohol; S3. performing plasma treatment on the pretreated NiO X thin film in a vacuum device at 80-150 DEG C to obtain a plasma-treated NiO X thin film; S4. depositing a SAM layer on the surface of the plasma-treated NiO X thin film and performing infrared treatment to obtain a NiO X / SAM double-layer hole transport layer. The preparation method can effectively enhance the interface connection between the NiO X thin film and the SAM layer, the uniform anchoring and film forming of SAM molecules, thereby improving the hole transport and extraction performance, improving the efficiency and stability of the solar cell.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and particularly relates to a NiO X / SAM double-layer hole transport layer, a preparation method thereof, and a solar cell. Background Art

[0002] Nickel oxide (NiO X , 0 < x ≤ 2) and self-assembled monolayers (SAMs) are commonly used hole transport layer materials in current high-efficiency inverted perovskite solar cells and perovskite / silicon heterojunction solar cells. The NiO X / SAM double-layer hole transport layer has the advantages of both materials and has received increasing attention.

[0003] NiO X The preparation method of the NiO X / SAM double-layer hole transport layer generally first prepares a NiO X film by magnetron sputtering, and then spin-coats SAM on the NiO X film to form a double-layer hole transport layer. The NiO X film prepared by magnetron sputtering has a high defect density and low conductivity, resulting in an increase in carrier recombination during hole transport. At the same time, the bonding force between the SAM and the NiO X film is insufficient, resulting in uneven distribution of the SAM, seriously affecting the hole transport and extraction effects, and further damaging the efficiency and stability of the perovskite solar cell. Therefore, the performance of the NiO Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems in the related art. For this purpose, an embodiment of the present invention provides a NiO X / SAM double-layer hole transport layer, a preparation method thereof, and a solar cell.

[0005] In a first aspect, an embodiment of the present invention provides a preparation method of a NiO X / SAM double-layer hole transport layer, including the following steps:

[0006] S1. Prepare a NiO X film on a conductive glass or a silicon bottom cell by magnetron sputtering;

[0007] S2. Coat a pretreatment liquid on the surface of the NiO X film to obtain a pretreated NiO X film, wherein the pretreatment liquid is a hydrogen peroxide solution, an acetic acid solution, or an alcohol;

[0008] S3. In a vacuum device, heat the pretreated NiOX The thin film was subjected to plasma treatment to obtain plasma-treated NiO. X film;

[0009] S4. NiO after plasma treatment X A SAM layer is deposited on the thin film surface and then subjected to infrared processing to obtain NiO. X / SAM dual-layer hole transport layer.

[0010] The advantages and technical effects of the preparation method of this invention are as follows:

[0011] (1) First in NiO X The film surface is coated with hydrogen peroxide solution, acetic acid solution, or alcohol, followed by plasma treatment. Plasma treatment generates active sites on the NiOx surface, which then react and bond with water / hydrogen peroxide / acetic acid / alcohol to form active sites on the NiOx film. X Introducing hydroxyl and / or carboxyl groups onto the film surface allows for a more tighter anchoring and binding of SAM molecules, thus promoting uniform SAM layer formation and enhancing NiO content. X Performance and buried performance of the SAM double-layer hole transport layer.

[0012] (2) In plasma treatment, the pretreated NiO X Maintaining the thin film at a temperature of 80-150℃ can produce NiO. X Ion migration on the film surface and in the bulk provides energy, which helps NiO X Repairing thin film defects can improve electron-hole recombination problems.

[0013] (3) Under the action of plasma and pretreatment solution, NiO X The change in film surface morphology and the reduction in roughness facilitate more and tighter bonding with the SAM layer.

[0014] (4) In summary, the preparation method of this embodiment of the invention involves NiO X Pretreatment and plasma treatment of the thin film surface can effectively enhance NiO. X The interfacial connection between the thin film and the SAM layer, as well as the uniform anchoring and film formation of SAM molecules, improve hole transport and extraction performance, thereby enhancing the efficiency and stability of perovskite solar cells.

[0015] According to the preparation method of this embodiment of the invention, in step S2, the concentration of the hydrogen peroxide aqueous solution is 0.6-3.0 mol / L; or, the concentration of the acetic acid solution is 0.5-3.3 mol / L.

[0016] According to the preparation method of the present invention, in step S2, the alcohol is at least one selected from ethanol, ethylene glycol, propanol, propylene glycol, butanol, and pentanol.

[0017] According to the preparation method of the present invention, in step S2, the coating method is at least one of spin coating, slot coating, blade coating, spray coating and printing.

[0018] According to the preparation method of the present invention, in step S3, the humidity inside the vacuum equipment chamber is 20-35%RH.

[0019] According to the preparation method of the present invention, in step S3, the plasma gas used in the plasma treatment is a mixture of Ar and O2, or a mixture of Ar and H2, or a mixture of Ar, H2 and O2; and / or, the process gas pressure of the plasma treatment is 1-8 mTorr; and / or, the power of the plasma treatment is 20-70 W; and / or, the time of the plasma treatment is 15-150 s.

[0020] According to the preparation method of the present invention, in step S4, the temperature of the infrared treatment is 100-150°C, and / or the time of the infrared treatment is 5-25 min.

[0021] Secondly, embodiments of the present invention provide a NiO X The / SAM double-layer hole transport layer is obtained by the preparation method of the first aspect.

[0022] NiO of the present invention X The advantages and technical effects of the SAM double-layer hole transport layer are as follows:

[0023] Because the preparation method of the first aspect is adopted, the NiO of the present invention embodiment X NiO in the SAM double-layer hole transport layer X The film has fewer defects and reduced surface roughness, resulting in a more uniform SAM layer. Furthermore, the bonding between the film and the SAM layer is tighter.

[0024] Thirdly, embodiments of the present invention provide a solar cell, wherein the solar cell is a perovskite cell or a perovskite / crystalline silicon tandem cell, and the solar cell includes NiO as described in the second aspect. x / SAM dual-layer hole transport layer.

[0025] The advantages and technical effects of the solar cells in this invention are as follows:

[0026] Due to the adoption of the second aspect of NiO X The solar cell of this invention has excellent efficiency and stability due to the presence of a double-layered hole transport layer (SAM). Detailed Implementation

[0027] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0028] In a first aspect, embodiments of the present invention provide a NiO X The method for preparing the / SAM double-layer hole transport layer includes the following steps:

[0029] S1. NiO is prepared on conductive glass or crystalline silicon substrate by magnetron sputtering. X film;

[0030] S2. Coat the NiO with the pretreatment solution. X The surface of the thin film is pretreated with NiO. X The film, wherein the pretreatment solution is a hydrogen peroxide solution, an acetic acid solution, or an alcohol;

[0031] S3. The pretreated NiO is subjected to treatment in a vacuum apparatus at 80-150°C. X The thin film was subjected to plasma treatment to obtain plasma-treated NiO. X film;

[0032] S4. NiO after plasma treatment X A SAM layer is deposited on the thin film surface and then subjected to infrared processing to obtain NiO. X / SAM dual-layer hole transport layer.

[0033] First in NiO X The film surface is coated with hydrogen peroxide solution, acetic acid solution, or alcohol, followed by plasma treatment. Plasma treatment generates active sites on the NiOx surface, which then react and bond with water / hydrogen peroxide / acetic acid / alcohol to form active sites on the NiOx film. X Introducing hydroxyl and / or carboxyl groups onto the film surface allows for a more tighter anchoring and binding of SAM molecules, thus promoting uniform SAM layer formation and enhancing NiO content. X Performance of the SAM double-layer hole transport layer and its buried-bottom performance (in the inverse structure, buried-bottom refers to the preparation of a hole transport layer beneath the perovskite layer). Additionally, the pretreated NiO is subjected to plasma processing... X Maintaining the thin film at a temperature of 80-150℃ can produce NiO. X Ion migration on the film surface and in the bulk provides energy, which helps NiO X Repairing thin film defects improves electron-hole recombination. Furthermore, under the influence of plasma and pretreatment solution, NiO... XThe surface morphology of the thin film changes and the roughness decreases, which is beneficial for more and closer connection with the SAM layer. In summary, the preparation method of the embodiment of the present invention is carried out on NiO X By pretreating the surface of the thin film and plasma treatment, the interface connection between the NiO X thin film and the SAM layer and the uniform anchoring and film formation of SAM molecules can be effectively enhanced, thereby improving the hole transport and extraction performance, and improving the efficiency and stability of the perovskite battery.

[0034] There is no particular limitation on the type of the NiO X (0 < x ≤ 2) thin film prepared in step S1. A non-doped NiO X target or a target doped with conductive metal elements such as Mg, Cu and / or Li can be used to obtain a non-doped NiO X thin film, or a NiO X thin film doped with conductive metal elements such as Mg, Cu and / or Li.

[0035] In some embodiments, in step S1, high-purity Ar gas is used for magnetron sputtering, the sputtering vacuum is maintained at 1-5 Pa, and the sputtering power is 50-150 W.

[0036] In some embodiments, the thickness of the NiO X thin film can be 5-15 nm, such as 5 nm, 7 nm, 9 nm, 11 nm, 13 nm, 15 nm, etc.

[0037] According to the preparation method of the embodiment of the present invention, in step S2, the concentration of the hydrogen peroxide solution is 0.6-3.0 mol / L; or, the concentration of the acetic acid solution is 0.5-3.3 mol / L. When the concentration of the above pretreatment solution is too low, too few hydroxyl groups and / or carboxyl groups are introduced on the surface of the NiO X thin film, which is not conducive to improving the anchoring effect between the NiO X thin film and the SEM layer, and thus is not conducive to the uniform film formation of the SAM layer, and thus is not conducive to improving the NiO X [[ID=३२]] / SAM bilayer hole transport layer performance and bottom burying performance.

[0038] [[ID=३५]]According to the preparation method of the embodiment of the present invention, in step S2, the alcohol is at least one of ethanol, ethylene glycol, propanol, propylene glycol, butanol and pentanol.

[0039] According to the preparation method of the embodiment of the present invention, in step S2, the coating method is at least one of spin coating, slot coating, knife coating, spraying and printing.

[0040] According to the preparation method of this embodiment of the invention, in step S3, the humidity inside the vacuum equipment chamber is 20-35% RH, for example 20% RH, 22% RH, 24% RH, 26% RH, 28% RH, 30% RH, 32% RH, 35% RH, etc. For NiO... X The thin film is subjected to a certain humidity (i.e., NiO) X Plasma treatment under conditions where the thin film surface is covered with water molecules, plasma treatment makes NiO X The active sites generated on the surface can react and bond with water in NiO X Introducing hydroxyl groups into the thin film surface allows for a more tighter anchoring and binding with SAM molecules, which is beneficial for uniform SAM layer formation and improves NiO yield. X Performance of the SAM double-layer hole transport layer and its buried performance. When the humidity inside the vacuum equipment chamber is too low, it is detrimental to fully realizing the aforementioned functions. Conversely, when the humidity inside the vacuum equipment chamber is too high, the surface adsorbed water molecules are not completely removed, affecting subsequent perovskite film formation and stability.

[0041] According to the preparation method of this embodiment of the invention, in step S3, the plasma gas used in the plasma treatment is a mixture of Ar and O2, or a mixture of Ar and H2, or a mixture of Ar, H2, and O2; and / or, the process gas pressure of the plasma treatment is 1-8 mTorr; and / or, the power of the plasma treatment is 20-70 W; and / or, the time of the plasma treatment is 15-150 s. Controlling the plasma treatment conditions within the above ranges can fully utilize the aforementioned plasma treatment effect, while also avoiding damage to NiO. X The thin film caused bombardment damage.

[0042] The preparation method of this invention does not impose any particular restrictions on the material used for the SAM layer in step S4. For example, the SAM material can be at least one of self-assembled organic monomers such as 2PACz-X, 4PACz-X, and Poly-4PACz, wherein X can be molecules or groups such as -H, -CH3, -OCH3, -Br, -Cl, and -F.

[0043] The preparation method of this invention does not particularly limit the method of depositing the SAM layer in step S4. For example, it can be carried out by spin coating, slot coating, blade coating, spraying, or printing. As an example, the SAM material can be prepared as a 0.3-1.2 mg / mL SAM solution, and then the SAM solution can be spin-coated onto NiO. X For the thin film surface, spin-coating is performed at 2000-5000 rpm for 20-60 seconds, followed by infrared treatment. Alternatively, a blade coating method can be used instead of spin-coating to coat the SAM solution onto NiO. X Thin film surface, doctor blade and NiOX The spacing between the films can be 50-160μm, and the coating is applied at a speed of 10-25mm / s. The films are then dried with a nitrogen air knife and subjected to infrared treatment.

[0044] According to the preparation method of this embodiment of the invention, in step S4, the infrared treatment temperature is 100-150℃, and / or the infrared treatment time is 5-25 min. The purpose of the infrared treatment is to anneal using the thermal effect, thereby reducing NiO. X Interface defects on the surface of the / SAM double-layer hole transport layer improve the efficiency of perovskite solar cells.

[0045] Secondly, embodiments of the present invention provide a NiO X The / SAM double-layer hole transport layer is obtained by the preparation method of the first aspect.

[0046] Because the preparation method of the first aspect is adopted, the NiO of the present invention embodiment X NiO in the SAM double-layer hole transport layer X The film has fewer defects and reduced surface roughness, resulting in a more uniform SAM layer. Furthermore, the bonding between the film and the SAM layer is tighter.

[0047] Thirdly, embodiments of the present invention provide a solar cell, wherein the solar cell is a perovskite cell or a perovskite / crystalline silicon tandem cell, and the solar cell includes NiO as described in the second aspect. X / SAM dual-layer hole transport layer.

[0048] Due to the adoption of the second aspect of NiO X The solar cell of this invention has excellent efficiency and stability due to the presence of a double-layered hole transport layer (SAM).

[0049] The present invention will now be described in detail with reference to the embodiments.

[0050] Example 1

[0051] (1) NiO with a thickness of 10 nm was prepared on TCO conductive glass by magnetron sputtering. X Thin film. Among them, magnetron sputtering uses undoped NiO. X The target material was high-purity Ar gas, the sputtering vacuum was maintained at 3.5 Pa, and the sputtering power was 100 W.

[0052] (2) Spin-coating the pretreatment solution onto NiO X The surface of the thin film is pretreated with NiO. X Thin film. A 0.85 mol / L hydrogen peroxide solution was prepared as a pretreatment solution, and 15 μL of the pretreatment solution was spin-coated onto NiO. XThe NiO film surface was spin-coated at 3000 rpm for 30 seconds to obtain the pretreated NiO. X film.

[0053] (3) Pretreated NiO was subjected to treatment at 120°C in a vacuum apparatus. X The thin film was subjected to plasma treatment to obtain plasma-treated NiO. X Thin film. The humidity inside the vacuum equipment chamber is 35%RH. The plasma gas used in the plasma treatment is a mixture of Ar and O2, with an Ar flow rate of 12 sccm and an O2 flow rate of 4 sccm. The process gas pressure of the plasma treatment is 5 mTorr, the plasma treatment power is 50W, and the plasma treatment time is 100s.

[0054] (4) NiO after plasma treatment X A SAM layer is deposited on the thin film surface and then subjected to infrared processing to obtain NiO. X / SAM double-layer hole transport layer. Specifically, the SAM material 2PACz-Br was prepared into a 0.3-1.2 mg / mL SAM solution, and then 2 μL of the SAM solution was spin-coated onto NiO. X The film surface was spin-coated at 3000 rpm for 40 seconds, followed by infrared treatment at 120°C for 15 minutes.

[0055] Example 2

[0056] The preparation method in this embodiment is the same as that in Example 1, except that the pretreatment solution is an acetic acid solution with a concentration of 1.2 mol / L.

[0057] Example 3

[0058] The preparation method of this embodiment is the same as that of Example 1, except that the pretreatment solution is a mixture of ethanol and propanol, and the volume ratio of ethanol to propylene glycol is 1:1.

[0059] Example 4

[0060] The preparation method in this embodiment is the same as that in Example 1, except that the pretreated NiO is prepared in a vacuum apparatus at 80°C. X The thin film is subjected to plasma treatment.

[0061] Example 5

[0062] The preparation method in this embodiment is the same as that in Example 1, except that the pretreated NiO is prepared in a vacuum apparatus at 150°C. X The thin film is subjected to plasma treatment.

[0063] Example 6

[0064] The preparation method of this embodiment is the same as that of Embodiment 1, except that the humidity inside the vacuum equipment chamber is 20%RH.

[0065] Example 7

[0066] The preparation method of this embodiment is the same as that of Example 1, except that the humidity in the vacuum equipment chamber is 10%RH.

[0067] Example 8

[0068] The preparation method in this embodiment is the same as that in Example 1, except that the humidity inside the vacuum equipment chamber is 55%RH.

[0069] Example 9

[0070] The preparation method in this embodiment is the same as that in Example 1, except that the plasma treatment uses a mixture of Ar and H2 gas, with an Ar flow rate of 10 sccm and an H2 flow rate of 3 sccm.

[0071] Comparative Example 1

[0072] The preparation method of this comparative example is the same as that of Example 1, except that step (2) is omitted.

[0073] Comparative Example 2

[0074] The preparation method of this comparative example is the same as that of Example 1, except that the pretreated NiO was prepared in a vacuum apparatus at 25°C. X The thin film is subjected to plasma treatment.

[0075] Performance testing

[0076] NiO obtained from various embodiments and comparative examples X After assembling the SAM double-layer hole transport layer into an inverted perovskite solar cell, the photoelectric conversion efficiency of the inverted perovskite solar cell was tested. The assembled inverted perovskite solar cell was then stored in a glove box for 30 and 60 days to measure its stability after a period of storage. The test results are shown in Table 1.

[0077] Table 1. Photovoltaic conversion efficiency and stability of inverted perovskite solar cells in each embodiment and comparative example.

[0078]

[0079] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0080] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A NiO X The method for preparing a / SAM double-layer hole transport layer is characterized by: Includes the following steps: S1. NiO is prepared on conductive glass or crystalline silicon substrate by magnetron sputtering. X film; S2. Coat the NiO with the pretreatment solution. X The surface of the thin film is pretreated with NiO. X The film, wherein the pretreatment solution is a hydrogen peroxide solution, an acetic acid solution, or an alcohol; S3. The pretreated NiO is subjected to treatment in a vacuum apparatus at 80-150°C. X The thin film was subjected to plasma treatment to obtain plasma-treated NiO. X film; S4. NiO after plasma treatment X A SAM layer is deposited on the thin film surface and then subjected to infrared processing to obtain NiO. X / SAM dual-layer hole transport layer.

2. The preparation method according to claim 1, characterized in that, In step S2, the concentration of the hydrogen peroxide solution is 0.6-3.0 mol / L; or, the concentration of the acetic acid solution is 0.5-3.3 mol / L.

3. The preparation method according to claim 1, characterized in that, In step S2, the alcohol is at least one of ethanol, ethylene glycol, propanol, propylene glycol, butanol, and pentanol.

4. The preparation method according to any one of claims 1-3, characterized in that, In step S2, the coating method is at least one of spin coating, slot coating, scraping coating, spraying and printing.

5. The preparation method according to any one of claims 1-3, characterized in that, In step S3, the humidity inside the vacuum equipment chamber is 20-35% RH.

6. The preparation method according to claim 1, characterized in that, In step S3, the plasma gas used in the plasma treatment is a mixture of Ar and O2, or a mixture of Ar and H2, or a mixture of Ar, H2 and O2; and / or, the process gas pressure of the plasma treatment is 1-8 mTorr; and / or, the power of the plasma treatment is 20-70 W; and / or, the time of the plasma treatment is 15-150 s.

7. The preparation method according to claim 1, characterized in that, In step S4, the infrared treatment temperature is 100-150℃, and / or the infrared treatment time is 5-25 min.

8. A NiO X / SAM dual-layer hole transport layer, characterized in that Obtained by the preparation method according to any one of claims 1-7.

9. A solar cell, characterized in that, The solar cell is a perovskite cell or a perovskite / crystalline silicon tandem cell, and the solar cell includes the NiO as described in claim 8. X / SAM dual-layer hole transport layer.

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