Perovskite thin film and application thereof

Abstract

The invention belongs to the technical field of photovoltaic materials, and particularly relates to a perovskite thin film and application thereof. The perovskite thin film comprises a perovskite material, a first solvent and a second solvent, the first solvent is prepared from N, N-dimethyl formamide and N-methyl-2-pyrrolidone, and the second solvent is prepared from N, N-dimethyl formamide and N-methyl-2-pyrrolidone; the second solvent comprises halogenated naphthalene. The beneficial effects of the invention are that the addition of the second solvent in the perovskite thin film can delay the volatilization of the solvent in the preparation process of the perovskite thin film, and reduce the growth speed of the perovskite material crystal, so as to obtain the perovskite thin film with large perovskite material grain size, few grain boundaries, good uniformity, good flatness and high compactness.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic materials, and in particular relates to a perovskite film and applications thereof. Background Art

[0002] Perovskite semiconductor materials are a class of materials with special structures and excellent properties. They are composed of perovskite crystal structures and have been widely used in optoelectronics, photovoltaics and other electronic device fields. Perovskite solar cells have attracted much attention due to their high photoelectric conversion efficiency and low manufacturing cost. One of the key factors limiting the practical application of large-area perovskite photovoltaic modules is the problem of the perovskite active layer, that is, how to prepare uniform, flat, dense and high-quality large-area perovskite films by regulating the crystallization growth kinetics.

[0003] At present, the mainstream large-area perovskite photovoltaic modules use a wet process to prepare the perovskite active layer, that is, first prepare the perovskite precursor solution, then obtain the wet film by wet methods such as coating, spraying, inkjet printing, etc., assisted by air knife or flash evaporation, and finally obtain the perovskite active layer film by thermal annealing. In the process of crystal growth kinetics, the rapid formation of a large number of crystal nuclei is the key to improving the uniformity, flatness and density of large-area perovskite films, and slow crystal growth is the key to improving the crystal quality of large-area perovskite films. Therefore, optimizing and regulating the composition of the precursor solution is the key to obtaining high-quality films.

[0004] N,N-dimethylformamide (DMF), which has strong solvating ability, is one of the most common solvents in the preparation of perovskite precursor solutions. However, the perovskite film formed when DMF is used as a solvent usually has a dendritic or island-like microstructure, resulting in significant differences in the vertical direction of the perovskite film. Summary of the invention

[0005] The present application provides a perovskite film and a preparation method and application thereof, aiming to solve the problem that when DMF is used as a solvent in the existing perovskite film preparation process, the perovskite film formed has differences in the vertical direction, resulting in poor transmission capacity of the perovskite photovoltaic module formed by the perovskite film.

[0006] In a first aspect, the present application provides a perovskite film, including a perovskite material, a first solvent and a second solvent;

[0007] The first solvent includes N,N-dimethylformamide and N-methyl-2-pyrrolidone;

[0008] The second solvent includes a halogenated naphthalene.

[0009] The addition of the second solvent to the perovskite film described in the present application can delay the volatilization of the solvent during the preparation of the perovskite film and reduce the growth rate of the perovskite material crystals, so as to obtain a perovskite film with large grain size, few grain boundaries, good uniformity, good flatness and high density.

[0010] According to some embodiments of the perovskite film described in the present application, the volume ratio of N,N-dimethylformamide to N-methyl-2-pyrrolidone in the first solvent is 7:(2-4).

[0011] According to some embodiments of the perovskite film described in the present application, the halogenated naphthalene includes one or more of 1-chloronaphthalene, 1-bromonaphthalene and 1-iodonaphthalene.

[0012] According to some embodiments of the perovskite film described in the present application, the halogenated naphthalene is 1-iodonaphthalene.

[0013] According to some embodiments of the perovskite film described in the present application, the volume ratio of the first solvent to the second solvent is 100:(1-20).

[0014] According to some embodiments of the perovskite film described in the present application, the volume ratio of the first solvent to the second solvent is 100:(1-10).

[0015] According to some embodiments of the perovskite film described in the present application, the particle size of the perovskite material grains in the perovskite film is 480-550 nm.

[0016] According to some embodiments of the perovskite film described in the present application, the thickness of the perovskite film is 200-1000 nm, preferably 300-600 nm.

[0017] The second aspect of the present application provides a perovskite photovoltaic module, comprising the perovskite film described in the first aspect of the present application.

[0018] According to some embodiments of the perovskite photovoltaic module described in the present application, it also includes a conductive glass layer, a hole transport layer, an electron transport layer and an electrode layer.

[0019] According to some embodiments of the perovskite photovoltaic module described in the present application, the thickness of the hole transport layer is 15-30 nm.

[0020] According to some embodiments of the perovskite photovoltaic module described in the present application, the thickness of the electron transport layer is 10-100 nm.

[0021] According to some embodiments of the perovskite photovoltaic module described in the present application, the thickness of the electrode layer is 100-300 nm. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a scanning electron microscope image of the perovskite film described in Example 1 of the present application;

[0023] Figure 2 This is a scanning electron microscope image of the perovskite film described in Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0024] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0025] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0026] An embodiment of the present application provides a perovskite film, including a perovskite material, a first solvent and a second solvent; the first solvent includes N,N-dimethylformamide and N-methyl-2-pyrrolidone; and the second solvent includes halogenated naphthalene.

[0027] The addition of the second solvent to the perovskite film described in the present application can delay the volatilization of the solvent during the preparation of the perovskite film and reduce the growth rate of the perovskite material crystals, so as to obtain a perovskite film with large grain size, few grain boundaries, good uniformity, good flatness and high density.

[0028] In some embodiments of the present application, the structural formula of the perovskite material is ABX3, wherein A includes one or more of MA, FA, PEA and Cs, MA is CH3NH3, FA is NH2CHNH2, and PEA is C8H9NH3; B includes one or two of Pb and Sn; and X includes one or more of Cl, Br, I and halides.

[0029] In some embodiments of the present application, the structural formula of the perovskite material is Cs x (FA) 1-x PbI x Br 3-x , where FA is NH2CHNH2.

[0030] In some embodiments of the present application, the perovskite material includes Cs 0.15 FA 0.85 PbI 2.55 Br 0.45 , Cs 0.1 FA 0.9 PbI3.

[0031] In some embodiments of the present application, the volume ratio of N,N-dimethylformamide and N-methyl-2-pyrrolidone in the first solvent is 7:(2-4), for example, 7:2, 7:3, 7:4, etc.

[0032] In some embodiments of the present application, the halogenated naphthalene includes one or more of 1-chloronaphthalene, 1-bromonaphthalene and 1-iodonaphthalene, preferably 1-iodonaphthalene.

[0033] In some embodiments of the present application, the volume ratio of the first solvent to the second solvent is 100:(1-20), for example, 100:1, 100:5, 100:7, 100:9, 100:12, 100:15, 100:18, 100:20, etc.

[0034] In some embodiments of the present application, the volume ratio of the first solvent to the second solvent is 100:(1-10), for example, 100:1, 100:3, 100:5, 100:8, 100:10, etc.

[0035] In some embodiments of the present application, the particle size of the perovskite material grains in the perovskite film is 480-550nm, for example, 480nm, 500nm, 520nm, 530nm, 550nm, etc.

[0036] In some embodiments of the present application, the thickness of the perovskite film is 200-1000nm, for example, 200nm, 450nm, 500nm, 520nm, 560nm, 650nm, 680nm, 780nm, 890nm, 960nm, 1000nm, etc.

[0037] In some embodiments of the present application, the thickness of the perovskite film is 300-600nm.

[0038] In some embodiments of the present application, the method for preparing the perovskite film includes the following steps: mixing a perovskite material, a first solvent, and a second solvent to obtain a mixed slurry, and preparing the perovskite film by a slit coating process using the mixed slurry.

[0039] A second aspect of the present application provides a perovskite photovoltaic module, comprising the perovskite film described in the first aspect of the present application.

[0040] In some embodiments of the present application, a conductive glass layer, a hole transport layer, an electron transport layer and an electrode layer are also included.

[0041] In some embodiments of the present application, the thickness of the hole transport layer is 15-30 nm, for example, 15 nm, 18 nm, 20 nm, 22 nm, 25 nm, 28 nm, 30 nm, etc.

[0042] In some embodiments of the present application, the thickness of the electron transport layer is 10-100 nm, for example, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 100 nm, etc.

[0043] In some embodiments of the present application, the thickness of the electrode layer is 100-300 nm, for example, 100 nm, 150 nm, 180 nm, 200 nm, 220 nm, 260 nm, 300 nm, etc.

[0044] The technical solution of the present application is further described below in conjunction with embodiments and drawings.

[0045] Example 1

[0046] A perovskite film comprising Cs with a particle size of 500 nm 0.15 FA 0.85 PbI 2.55 Br 0.45 Perovskite material, N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP) and 1-chloronaphthalene, wherein the mass ratio of the perovskite material to the solvent (N,N-dimethylformamide, N-methyl-2-pyrrolidone and 1-chloronaphthalene) is 1:10;

[0047] The volume ratio of N,N-dimethylformamide and N-methyl-2-pyrrolidone is 7:3;

[0048] The volume ratio of the total volume of N,N-dimethylformamide and N-methyl-2-pyrrolidone to the volume of 1-chloronaphthalene is 100:1.

[0049] The method for preparing the perovskite film in Example 1 comprises: 0.15 FA 0.85 PbI 2.55 Br 0.45 , N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP) and 1-chloronaphthalene are mixed to obtain a mixed slurry, and the mixed slurry is prepared by a slit coating process to obtain a perovskite film.

[0050] Example 2

[0051] The perovskite film described in Example 2 is different from that in Example 1 only in that the volume ratio of N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP) and 1-chloronaphthalene is 70:30:2.

[0052] The specific steps include:

[0053] The method for preparing the perovskite film in Example 2 comprises: preparing a perovskite material Cs with a particle size of 500 nm; 0.15 FA 0.85 PbI 2.55 Br 0.45 , N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP) and 1-chloronaphthalene are mixed, wherein the mass ratio of the perovskite material to the solvent (N,N-dimethylformamide, N-methyl-2-pyrrolidone and 1-chloronaphthalene) is 1:10, the volume ratio of N,N-dimethylformamide and N-methyl-2-pyrrolidone is 7:3; the volume ratio of the total volume of N,N-dimethylformamide and N-methyl-2-pyrrolidone to 1-chloronaphthalene is 100:2; a mixed slurry is obtained, and the mixed slurry is used to prepare a perovskite film by a slit coating process.

[0054] Example 3

[0055] The perovskite film described in Example 3 is different from that in Example 1 only in that the volume ratio of N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP) and 1-chloronaphthalene is 70:30:3.5.

[0056] The specific steps include:

[0057] The method for preparing the perovskite film in Example 3 comprises: preparing a perovskite material Cs with a particle size of 500 nm. 0.15 FA 0.85 PbI 2.55 Br 0.45 , N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP) and 1-chloronaphthalene are mixed, wherein the mass ratio of the perovskite material to the solvent (N,N-dimethylformamide, N-methyl-2-pyrrolidone and 1-chloronaphthalene) is 1:10, the volume ratio of N,N-dimethylformamide and N-methyl-2-pyrrolidone is 7:3; the volume ratio of the total volume of N,N-dimethylformamide and N-methyl-2-pyrrolidone to 1-chloronaphthalene is 100:3.5; a mixed slurry is obtained, and the mixed slurry is used to prepare a perovskite film by a slit coating process.

[0058] Example 4

[0059] The perovskite film described in Example 4 is different from that in Example 1 only in that the volume ratio of N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP) and 1-chloronaphthalene is 70:30:7.

[0060] The specific steps include:

[0061] The method for preparing the perovskite film in Example 4 comprises: preparing a perovskite material Cs with a particle size of 500 nm; 0.15 FA 0.85 PbI 2.55 Br 0.45 , N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP) and 1-chloronaphthalene are mixed, wherein the mass ratio of the perovskite material to the solvent (N,N-dimethylformamide, N-methyl-2-pyrrolidone and 1-chloronaphthalene) is 1:10, the volume ratio of N,N-dimethylformamide and N-methyl-2-pyrrolidone is 7:3; the volume ratio of the total volume of N,N-dimethylformamide and N-methyl-2-pyrrolidone to 1-chloronaphthalene is 100:7; a mixed slurry is obtained, and the mixed slurry is used to prepare a perovskite film by a slit coating process.

[0062] Example 5

[0063] The perovskite film described in Example 5 is different from that in Example 1 only in that the volume ratio of N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP) and 1-chloronaphthalene is 70:30:12.

[0064] The specific steps include:

[0065] The method for preparing the perovskite film in Example 5 comprises: preparing a perovskite material Cs with a particle size of 500 nm. 0.15 FA 0.85 PbI 2.55 Br 0.45 , N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP) and 1-chloronaphthalene are mixed, wherein the mass ratio of the perovskite material to the solvent (N,N-dimethylformamide, N-methyl-2-pyrrolidone and 1-chloronaphthalene) is 1:10, the volume ratio of N,N-dimethylformamide and N-methyl-2-pyrrolidone is 7:3; the volume ratio of the total volume of N,N-dimethylformamide and N-methyl-2-pyrrolidone to 1-chloronaphthalene is 100:12; a mixed slurry is obtained, and the mixed slurry is used to prepare a perovskite film by a slit coating process.

[0066] Example 6

[0067] The difference between the perovskite film described in Example 6 and Example 1 is that the second solvent used in the perovskite film described in Example 6 is 1-bromonaphthalene, and the rest of the operations are the same as those in Example 1.

[0068] Example 7

[0069] The difference between the perovskite film described in Example 7 and Example 1 is that the second solvent used in the perovskite film described in Example 7 is 1-iodonaphthalene, and the rest of the operations are the same as those in Example 1.

[0070] Example 8

[0071] The difference between the perovskite film in Example 8 and that in Example 1 is that the perovskite material used in the perovskite film in Example 8 is Cs 0.1 FA 0.9 PbI3, and the rest of the operations are the same as in Example 1.

[0072] Comparative Example 1

[0073] The difference between the perovskite film described in Comparative Example 1 and Example 1 is that no second solvent is added during the preparation of the perovskite film described in Comparative Example 1, and the rest of the operations are the same as those in Example 1.

[0074] Performance study of the perovskite films described in Examples 1-8 and Comparative Example 1 of the present application:

[0075] The perovskite thin films described in Examples 1 to 8 of the present application and Comparative Example 1 are respectively used to prepare perovskite photovoltaic modules, and the preparation method includes:

[0076] (1) The FTO substrate was ultrasonically treated with deionized water, acetone, and isopropanol for 15 minutes respectively, then cleaned with a UV cleaner for 10 minutes, and then dried with a nitrogen stream for later use;

[0077] (2) On the nitrogen-dried substrate, 20 nm thick NiO was deposited by magnetron sputtering. x hole transport layer;

[0078] (3) The perovskite films described in Examples 1-8 and Comparative Example 1 were deposited on the hole transport layer by a slit coating process, followed by annealing at 150°C for 30 min to obtain a perovskite film with a thickness of 450 nm. The annealed substrate was moved into a vacuum chamber, and a C60 electron transport layer and a BCP modification layer were sequentially prepared by vacuum thermal evaporation. The C60 evaporation rate was 5 nm / s and the thickness was 350 nm; the BCP evaporation rate was 5 nm / s; and then an RPD device was used to reactively deposit 160 nm thick IWO as the back electrode of the perovskite photovoltaic module.

[0079] The performance of the perovskite photovoltaic modules obtained by the perovskite thin films described in Examples 1-8 and Comparative Example 1 was studied, and the results are shown in Table 1:

[0080] Table 1

[0081] Photoelectric conversion efficiency (%) Example 1 14.2％ Example 2 14.6％ Example 3 15.8％ Example 4 15.7％ Example 5 15.0％ Example 6 13.8％ Example 7 16.0％ Example 8 14.3％ Comparative Example 1 13.0％

[0082] The scanning electron microscope image of the perovskite film described in Example 1 of the present application is as follows Figure 2 As shown, the scanning electron microscope image of the perovskite film in Comparative Example 1 is as follows Figure 1 shown.

[0083] from Figure 1 and Figure 2 It can be seen that: Figure 1 The microstructure of the perovskite film prepared without the addition of 1-chloronaphthalene is described. It can be seen that the size of the grains in the film is mostly less than 200 μm; Figure 2 Describes the perovskite films prepared under the condition of adding 1-chloronaphthalene, whose grain size is compared with Figure 1 As shown in the figure, the maximum size is over 500 μm. Therefore, the addition of 1-halonaphthalene can adjust and optimize the grain size in the perovskite film, thereby obtaining high-quality perovskite films, laying a solid foundation for the preparation of high-efficiency perovskite photovoltaic modules.

[0084] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A perovskite film, characterized in that: including a perovskite material, a first solvent and a second solvent; The first solvent includes N,N-dimethylformamide and N-methyl-2-pyrrolidone; The second solvent includes a halogenated naphthalene.

2. The perovskite film according to claim 1, characterized in that The volume ratio of N,N-dimethylformamide to N-methyl-2-pyrrolidone in the first solvent is 7:(2-4).

3. The perovskite film according to claim 1, characterized in that The halogenated naphthalene includes one or more of 1-chloronaphthalene, 1-bromonaphthalene and 1-iodonaphthalene, preferably 1-iodonaphthalene.

4. The perovskite film according to claim 1, characterized in that The volume ratio of the first solvent to the second solvent is 100:(1-20).

5. The perovskite film according to claim 1, characterized in that: The volume ratio of the first solvent to the second solvent is 100:(1-10).

6. The perovskite film according to claim 1, characterized in that: The grain size of the perovskite material grains in the perovskite film is 480-550nm.

7. The perovskite film according to claim 1, characterized in that: The thickness of the perovskite film is 200-1000 nm, preferably 300-600 nm.

8. A perovskite photovoltaic module, characterized in that: Comprising the perovskite film according to any one of claims 1 to 7.

9. The perovskite photovoltaic module according to claim 8, characterized in that: It also includes a conductive glass layer, a hole transport layer, an electron transport layer and an electrode layer.

10. The perovskite photovoltaic module according to claim 9, characterized in that: The thickness of the hole transport layer is 15-30 nm; And / or, the thickness of the electron transport layer is 10-100 nm; And / or, the thickness of the electrode layer is 100-300 nm.

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