Perovskite thin film with passivation layer and preparation method and application thereof

Abstract

The invention relates to a perovskite thin film with a passivation layer and a preparation method and application thereof, and belongs to the technical field of photovoltaic devices. The preparation method comprises the following steps: S1, sequentially evaporating an inorganic salt layer and an organic salt layer on the surface of a substrate to form a perovskite thin film; s2, evaporating a passivating agent on the surface of the perovskite thin film, and annealing to obtain the perovskite thin film with a passivation layer; the passivating agent is a phenanthroline compound. The defects of the perovskite thin film can be effectively inhibited and the crystal quality of the thin film can be improved by evaporating the passivating agent on the perovskite thin film and co-annealing, which is realized as the passivating agent and uncoordinated metal ions form coordinate bonds, so that the defects of the perovskite thin film are greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic devices, and in particular relates to a perovskite film with a passivation layer and a preparation method and application thereof. Background Art

[0002] Perovskite solar cells, as a new photovoltaic technology based on special ABX3 crystal structure materials, have quickly become a research hotspot since they were first applied to dye-sensitized solar cells in 2009, especially after the development of pure perovskite solar cells in 2012. Its high photoelectric conversion efficiency, low-cost manufacturing potential, and the adjustability of material properties have enabled it to exceed 26% in laboratory efficiency in just a few years, showing great application prospects. However, this technology also faces problems such as insufficient stability, environmental impact, and challenges in large-scale production. Currently, the scientific research community is committed to improving its long-term stability and promoting the commercialization of this technology, which is expected to make important contributions to the global energy transformation in the future.

[0003] Passivators significantly improve the performance and stability of perovskite solar cells, effectively reduce surface and grain boundary defects, improve photoelectric conversion efficiency, and enhance resistance to environmental factors such as humidity and oxygen, thereby extending the working life of the device. At the same time, they optimize the interface characteristics between the charge transport layer and the perovskite layer, promoting better charge separation and transfer.

[0004] Currently, perovskite photovoltaic cells mostly use wet passivation treatment methods, but this treatment method will cause adverse chemical reactions between the passivator and the perovskite material, resulting in decreased long-term stability. In addition, since wet treatment usually involves organic solvents, these solvents will remain in the perovskite layer, thereby affecting device performance. Furthermore, this method increases the complexity of the preparation process and requires additional steps to ensure that the passivator is evenly distributed and works effectively. This not only increases manufacturing costs, but also leads to reduced production efficiency, which is not conducive to the industrial production of perovskite photovoltaic cells.

[0005] The evaporation process is suitable for integration into large-scale production processes because it can ensure precise control of dosage and uniformity. However, in actual operation, there are a large number of uncoordinated lead ions in the evaporated perovskite film, which leads to an increase in device defects and limits the improvement of device performance. Therefore, it is urgent to develop a new method to prepare the passivation layer and improve the performance of perovskite films and related devices. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a perovskite film with a passivation layer and a preparation method and application thereof, by introducing a passivator in the process of sequential evaporation to prepare the perovskite film, using the passivator to coordinate with uncoordinated metal ions, effectively suppressing the defects of the perovskite film and improving the crystallization quality of the perovskite film. In addition, the present invention realizes the full evaporation preparation of the perovskite photovoltaic device through the optimization of the material of the passivation layer and the ratio of the perovskite film and the evaporation process, which is conducive to the industrial production of perovskite solar cells, and the prepared perovskite photovoltaic device has high conversion efficiency and good stability.

[0007] The first object of the present invention is to provide a method for preparing a perovskite film having a passivation layer, comprising the following steps:

[0008] S1, sequentially evaporating an inorganic salt layer and an organic salt layer on the surface of the substrate to form a perovskite film;

[0009] S2. Vapor-depositing a passivating agent on the surface of the perovskite film described in S1, and annealing to obtain the perovskite film having a passivation layer; the passivating agent is a phenanthroline compound.

[0010] In one embodiment of the present invention, in S1, the material of the inorganic salt layer is selected from one or more of lead iodide (PbI2), lead chloride (PbCl2), lead bromide (PbBr2), cesium iodide (CsI) and cesium bromide (CsBr); the evaporation rate of the inorganic salt layer is For example, it can be wait;

[0011] The material of the organic salt layer is selected from formamidine hydroiodide (FAI) and / or methylamine hydrochloride (MACl); the evaporation rate of the organic salt layer is For example, it can be wait.

[0012] In one embodiment of the present invention, the amount of the inorganic salt and the organic salt satisfies the general formula MA x FA 1- y Cs y PbB z Cl t I 3-z-t ; Among them, 0≤x≤0.1, 0≤y≤0.1, 0≤z≤0.2, 0≤t≤0.2.

[0013] In one embodiment of the present invention, in S2, the phenanthroline compound is selected from one or more of 4,7-diphenyl-1,10-phenanthroline (BPhen), 2,9-dibromo-4,7-diphenyl-1,10-phenanthroline and 2,9-dichloro-4,7-diphenyl-1,10-phenanthroline; the evaporation rate of the passivation layer is For example, it can be wait.

[0014] In one embodiment of the present invention, in S2, the annealing temperature is 140°C-170°C, for example, it can be 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, etc.; the time is 10min-20min, for example, it can be 10min, 11min, 12min, 13min, 14min, 15min, 16min, 17min, 18min, 19min, 20min, etc.

[0015] The second object of the present invention is to provide a perovskite film with a passivation layer, wherein the perovskite film with a passivation layer is prepared by the method described.

[0016] The third object of the present invention is to provide a perovskite photovoltaic cell, which comprises one or more of a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, a hole blocking layer and an electrode layer arranged in sequence; the perovskite layer is the perovskite film with a passivation layer as described in claim 6.

[0017] In one embodiment of the present invention, the material of the hole transport layer is selected from one or more of [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphonic acid (Me-2PACz), (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (MeO-2PACz), (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz), [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz) and polymer SAM (Poly-SAM);

[0018] The material of the electron transport layer is selected from fullerene (C60) and / or tin oxide (SnO2);

[0019] The material of the hole blocking layer is selected from 4,7-diphenyl-1,10-phenanthroline (BPhen) and / or 2,2',2"-(1,3,5-triphenylbenzene)-tris[1-phenyl-1H-benzimidazole] (TPBi);

[0020] The material of the electrode layer is selected from one or more of silver (Ag), gold (Au) and copper (Cu).

[0021] In one embodiment of the present invention, the thickness of the hole transport layer is 2nm-50nm, for example, 2nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, etc.;

[0022] The thickness of the inorganic salt layer in the perovskite film with a passivation layer is 250nm-350nm, for example, it can be 250nm, 255nm, 260nm, 265nm, 270nm, 275nm, 280nm, 285nm, 290nm, 295nm, 300nm, 305nm, 310nm, 315nm, 320nm, 325nm, 330nm, 335nm, 340nm, 345nm, 350nm, etc.; the thickness of the organic salt layer is 325nm-375nm, for example, it can be 325nm, 330nm, 335nm, 340nm, 345nm, 350nm, 355nm, 360nm, 365nm, 370nm, 375nm, etc.;

[0023] The thickness of the electron transport layer is 5nm-20nm, for example, 5nm, 10nm, 15nm, 20nm, etc.;

[0024] The thickness of the hole blocking layer is 5nm-15nm, for example, 5nm, 10nm, 15nm, etc.;

[0025] The thickness of the electrode layer is 50 nm-200 nm, for example, 50 nm, 100 nm, 150 nm, 200 nm, etc.

[0026] The fourth object of the present invention is to provide a method for preparing a perovskite photovoltaic cell, comprising the following steps: sequentially vapor-depositing a hole transport layer, a perovskite film with a passivation layer, an electron transport layer, a hole blocking layer and an electrode layer on a conductive substrate to obtain the perovskite photovoltaic cell; the material of the hole transport layer is pre-melted before vapor deposition.

[0027] In one embodiment of the present invention, the pre-melting process is performed by using a vapor deposition machine with a current of 41A-49A for 5min-20min. Pre-melting ensures the subsequent stable vapor deposition, and the material rate during the vapor deposition process will be very stable. If the pre-melting process is not performed, the air pressure in the cavity will fluctuate violently, the rate will be extremely unstable, and the material will easily decompose.

[0028] In one embodiment of the present invention, the evaporation rate of the hole transport layer is For example, it can be wait;

[0029] The evaporation rate of the electron transport layer is For example, it can be wait;

[0030] The evaporation rate of the hole blocking layer is For example, it can be wait.

[0031] The technical solution of the present invention has the following advantages over the prior art:

[0032] (1) The preparation method of the present invention can effectively suppress the defects of the perovskite film and improve the crystallization quality of the film by evaporating the passivator on the perovskite film and co-annealing. This is because the passivator forms coordination bonds with uncoordinated metal ions, which greatly reduces the defects of the perovskite film.

[0033] (2) The perovskite photovoltaic cell of the present invention has high photoelectric conversion efficiency and good stability. 2 ) device achieved a conversion efficiency of 19.83%. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0035] Figure 1 The SEM and GIWAXS images of Test Example 1 of the present invention; wherein a is a surface SEM image of Comparative Example 1, b is a surface SEM image of Example 1, c is a cross-sectional SEM image of Comparative Example 1, d is a cross-sectional SEM image of Example 1, e is a GIWAXS image of Comparative Example 1, and f is a GIWAXS image of Example 1;

[0036] Figure 2 This is the XPS graph of Test Example 1 of the present invention;

[0037] Figure 3 FTIR graph of Test Example 1 of the present invention;

[0038] Figure 4 This is a schematic diagram of the reaction of uncoordinated lead ions induced by BPhen co-evaporation in the present invention;

[0039] Figure 5 This is a current density-voltage characteristic curve of the perovskite photovoltaic device of Comparative Example 1 and Example 1 in Test Example 2 of the present invention. DETAILED DESCRIPTION

[0040] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. It should be understood that the specific embodiments are only used to explain the present invention, but the embodiments are not intended to limit the present invention.

[0041] In the present invention, unless otherwise explained, technical and scientific terms used in the present invention have the same meanings as commonly understood by those skilled in the art to which the present invention belongs.

[0042] In the present invention, unless otherwise stated, the term "and / or" used in the present invention includes any and all combinations of one or more of the associated listed items.

[0043] In the present invention, unless otherwise stated, the experimental methods used in the embodiments of the present invention are conventional methods unless otherwise stated, and the materials, reagents, etc. used are all commercially available unless otherwise stated.

[0044] In the present invention, unless otherwise stated, when the terms "comprise" and / or "include" are used in the specification of the present invention, it indicates the existence of the described features, integers, steps, operations, raw materials or components, but does not exclude the existence or addition of one or more other features, integers, steps, operations, raw materials, components or their combinations.

[0045] Example 1

[0046] The perovskite photovoltaic cell and the preparation method thereof of this embodiment specifically include the following steps:

[0047] S1 and ITO substrates were cleaned in ultrasonic bath with deionized water, acetone and ethanol for 15 min each;

[0048] S2, move the treated ITO substrate to the evaporation chamber, pre-melt Me-2PACz at a current of 45.2A for 15min, then cool to room temperature, and then Me-2PACz was evaporated at a rate of 1000 to obtain a hole transport layer with a thickness of 15 nm;

[0049] S3, continue to co-evaporate PbI2, PbCl2 and CsI on the hole transport layer to form an organic salt layer with a total thickness of about 300nm. The evaporation rate of PbI2 is The evaporation rate of PbCl2 is The evaporation rate of CsI is Then, FAI was evaporated at a rate of 1.5 to form an inorganic salt layer with a thickness of about 350 nm. BPhen was evaporated at a rate of 1.5 to form a passivation layer with a thickness of about 5 nm, and then annealed at 150° C. for 15 min to obtain a perovskite layer, i.e., a perovskite film with a passivation layer;

[0050] S4, on the perovskite layer C60 was evaporated at a rate of 100 to form an electron transport layer with a thickness of 10 nm;

[0051] S5, on the electron transport layer BPhen was evaporated at a rate of 100 to form a hole blocking layer with a thickness of 10 nm;

[0052] S6. Vapor-deposit an Ag electrode layer with a thickness of about 100 nm on the hole blocking layer to obtain a perovskite photovoltaic device.

[0053] Example 2

[0054] The method is basically the same as Example 1, except that the hole transport layer material is replaced by Poly-SAM.

[0055] Example 3

[0056] The method is basically the same as Example 1, except that the hole transport layer material is replaced with MeO-2PACz.

[0057] Example 4

[0058] The method is basically the same as Example 1, except that the hole transport layer material is replaced with 2PACz.

[0059] Comparative Example 1

[0060] The process is basically the same as Example 1, except that no passivation layer is prepared.

[0061] Comparative Example 2

[0062] The method is basically the same as Example 1, except that the hole transport layer is prepared by spin coating at a rotation speed of 3000 rpm for 30 seconds and annealing at 100° C. for 10 minutes.

[0063] Test Example 1

[0064] Based on Example 1 and Comparative Example 1, the perovskite layer was characterized by SEM and GIWAXS. The results are as follows Figure 1 As shown. Figure 1 a- Figure 1 From the SEM image of the surface in (b), it can be seen that the perovskite film with the introduction of BPhen shows less PbI2 and a continuous large grain size, indicating an improvement in the quality of the perovskite film. Figure 1 c- Figure 1 The cross-sectional SEM image of (d) shows that the introduction of BPhen can effectively improve the crystalline quality of the perovskite film. Figure 1 e- Figure 1 From the GIWAXS graph of Figure 1, it can be seen that the perovskite film without BPhen in comparative example 1 shows a stronger PbI2 peak; the disappearance of the PbI2 peak in example 1 with BPhen further illustrates the reduction of uncoordinated lead ions. It can be seen that the introduction of the passivating agent BPhen can effectively reduce film defects, improve the crystallization of perovskite, and thus obtain high-quality perovskite films.

[0065] To further explore the mechanism of the passivation agent in the formation of perovskite films, XPS characterization was performed on BPhen-treated PBI2 (denoted as BPhen+PbI2) and untreated PbI2 (denoted as PbI2). Figure 2 As shown. Figure 2 It can be seen that for the PBI2 film, Pb 4f has two peaks, 137.6 eV and 142.5 eV respectively. After BPhen treatment, both peaks of Pb 4f move toward the high binding energy direction by 0.2 eV, indicating that BPhen can interact with the Pb element in PbI2.

[0066] FTIR was then used to characterize the changes in the stretching vibration peaks in BPhen and BPhen+PbI2. Figure 3 As shown. Figure 3 It can be seen that with the introduction of PbI2, the original position of the C=N stretching vibration peak changed from 1602cm -1 Move to 1610cm -1 , indicating that through the BPhen buried interface treatment, the lone pair electrons of the N atom in BPhen will interact with the uncoordinated Pb 2 + interaction, thereby improving the upper interface.

[0067] Figure 4 Schematic diagram of the reaction of uncoordinated lead ions induced by BPhen co-evaporation. Figure 4 It can be seen that the N in BPhen forms a strong coordination bond with the uncoordinated lead ions in the perovskite, and a π-π stacking effect is formed between the benzene ring in BPhen and the aromatic ring on the fullerene.

[0068] Test Example 2

[0069] Using a Keithley 2400 source meter at 100mWcm -2 The perovskite photovoltaic devices of Comparative Examples 1-2 and Examples 1-4 were tested at a simulated AM 1.5G spectrum (0.1 cm 2 ) with a fixed voltage range of 0 to 1.2 V. Figure 5 As shown in Table 1:

[0070] Table 1

[0071] Sample Conversion efficiency (%) Example 1 19.83 Example 2 18.02 Example 3 17.75 Example 4 17.22 Comparative Example 1 16.64 Comparative Example 2 16.39

[0072] From Table 1 and Figure 5 It can be seen that the conversion efficiency of the perovskite photovoltaic device of Example 1 is 19.83%, while the conversion efficiencies of the perovskite photovoltaic devices of Comparative Examples 1-2 are only 16.64% and 16.39%.

[0073] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for preparing a perovskite film having a passivation layer, characterized in that: The following steps are involved: S1, sequentially evaporating an inorganic salt layer and an organic salt layer on the surface of the substrate to form a perovskite film; S2. Vapor-depositing a passivating agent on the surface of the perovskite film described in S1, and annealing to obtain the perovskite film having a passivation layer; the passivating agent is a phenanthroline compound.

2. The method for preparing a perovskite film with a passivation layer according to claim 1, characterized in that: In S1, the material of the inorganic salt layer is selected from one or more of lead iodide, lead chloride, lead bromide, cesium iodide and cesium bromide; the evaporation rate of the inorganic salt layer is The material of the organic salt layer is selected from formamidine hydroiodide and / or methylamine hydrochloride; the evaporation rate of the organic salt layer is 3. The method for preparing a perovskite film with a passivation layer according to claim 2, characterized in that: The amount of the inorganic salt and the organic salt meets the general formula MA x FA 1-y Cs y PbB z Cl t I 3-z-t ; Among them, 0≤x≤0.1, 0≤y≤0.1, 0≤z≤0.2, 0≤t≤0.

2.

4. The method for preparing a perovskite film with a passivation layer according to claim 1, characterized in that: In S2, the phenanthroline compound is selected from one or more of 4,7-diphenyl-1,10-phenanthroline, 2,9-dibromo-4,7-diphenyl-1,10-phenanthroline and 2,9-dichloro-4,7-diphenyl-1,10-phenanthroline; the evaporation rate of the passivation layer is 5. The method for preparing a perovskite film with a passivation layer according to claim 1, characterized in that: In S2, the annealing temperature is 140°C-170°C, and the time is 10min-20min.

6. A perovskite film having a passivation layer, characterized in that: The perovskite film with a passivation layer is prepared by the method according to any one of claims 1 to 5.

7. A perovskite photovoltaic cell, characterized in that: The perovskite photovoltaic cell comprises one or more of a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, a hole blocking layer and an electrode layer arranged in sequence; the perovskite layer is the perovskite film with a passivation layer as described in claim 6.

8. The perovskite photovoltaic cell according to claim 7, characterized in that: The material of the hole transport layer is selected from one or more of [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphonic acid, (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid, (2-(9H-carbazole-9-yl)ethyl)phosphonic acid, [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid and polymer SAM; The material of the electron transport layer is selected from fullerene and / or tin oxide; The material of the hole blocking layer is selected from 4,7-diphenyl-1,10-phenanthroline and / or 2,2',2"-(1,3,5-triphenylbenzene)-tris[1-phenyl-1H-benzimidazole]; The material of the electrode layer is selected from one or more of silver, gold and copper.

9. The perovskite photovoltaic cell according to claim 7, characterized in that: The thickness of the hole transport layer is 2nm-50nm; The thickness of the inorganic salt layer in the perovskite film with a passivation layer is 250nm-350nm, the thickness of the organic salt layer is 325nm-375nm, and the thickness of the passivation layer is 3nm-10nm; The thickness of the electron transport layer is 5nm-20nm; The thickness of the hole blocking layer is 5nm-15nm; The thickness of the electrode layer is 50nm-200nm.

10. A method for preparing a perovskite photovoltaic cell according to any one of claims 7 to 9, characterized in that: A hole transport layer, a perovskite film with a passivation layer, an electron transport layer, a hole blocking layer and an electrode layer are sequentially evaporated on a conductive substrate to obtain the perovskite photovoltaic cell; the material of the hole transport layer is pre-melted before evaporation.

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