A double-layer perovskite film, a preparation method and application thereof

Abstract

This invention discloses a bilayer perovskite thin film, its preparation method, and its application; this invention belongs to the field of optoelectronic device technology; the preparation method includes the following steps: S1, mixing and coating a FASnI3 precursor solution and a MAPbI3 precursor solution onto a pretreated transfer medium surface, spin-coating by an anti-solvent method, and annealing to obtain a film containing (FASnI3). 1‑x (MAPbI3) x Transfer medium for perovskite thin films; x is 0.1–1; S2, containing (FASnI3) 1‑x (MAPbI3) x The perovskite film transfer medium is hot-pressed onto the FAPbI3 perovskite film, and the transfer medium is then removed to obtain a bilayer perovskite film. This invention improves the preparation quality and efficiency of bilayer perovskite films; it broadens the light absorption range of the perovskite film and increases the photoelectric conversion efficiency of solar cells prepared from bilayer perovskite films.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic device technology, and in particular to a bilayer perovskite thin film, its preparation method, and its application. Background Technology

[0002] Perovskite solar cells have become a research hotspot due to their high efficiency, low cost, and ability to be fabricated at low temperatures. However, the widely used FAPbI3 perovskite suffers from a wide band gap and a limited absorption spectrum, restricting further improvements in its photoelectric conversion efficiency. Furthermore, the traditional solution spin-coating method is difficult to apply directly to the preparation of bilayer perovskites because the solvent used to prepare the second layer can damage the first layer.

[0003] Therefore, it is necessary to develop a new method for preparing bilayer perovskite thin films. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the first aspect of the present invention proposes a method for preparing a bilayer perovskite thin film, which produces a high-quality bilayer perovskite thin film with a wide light absorption range and high photoelectric conversion efficiency.

[0005] A second aspect of the present invention also provides a bilayer perovskite thin film.

[0006] A third aspect of the present invention also provides a perovskite solar cell.

[0007] A method for preparing a bilayer perovskite thin film according to a first aspect embodiment of the present invention includes the following steps:

[0008] S1. A mixture of FASnI3 precursor solution and MAPbI3 precursor solution is coated onto the surface of a pretreated transfer medium. The mixture is then spin-coated using an anti-solvent method and annealed to obtain a solution containing (FASnI3). 1-x (MAPbI3) x Transfer medium for perovskite thin films; x is 0.1 to 1;

[0009] S2, containing (FASnI3) 1-x (MAPbI3) x The perovskite film transfer medium is hot-pressed with the FAPbI3 perovskite film, and the transfer medium is removed to obtain a bilayer perovskite film.

[0010] The preparation method according to embodiments of the present invention has at least the following beneficial effects:

[0011] This invention utilizes a physical transfer method with a transfer medium to prepare bilayer perovskite films, avoiding the damage to the preceding perovskite film caused by chemical solution methods and improving the preparation quality and efficiency of bilayer perovskite films. This is achieved by controlling (FASnI3). 1-x (MAPbI3) x The composition of the perovskite thin film reduces the interaction force with the transfer medium, increasing its transferability. Furthermore, the bilayer perovskite thin film broadens the light absorption range of the perovskite film, improving the photoelectric conversion efficiency of solar cells fabricated from the bilayer perovskite thin film.

[0012] According to some embodiments of the present invention, the transfer medium is selected from at least one of polydimethylsiloxane, polyethylene terephthalate film, polyimide film, polycarbonate film, polyurethane film, silicone rubber, or hydrogel. Therefore, when the transfer medium is selected from the above-mentioned substances, it has high transfer capability.

[0013] According to some embodiments of the present invention, in step S2, the hot-pressing pressure is 20 MPa to 80 MPa. Excessive hot-pressing pressure can easily cause the film to crack, while insufficient pressure can prevent complete contact between the films, resulting in incomplete transfer. Therefore, when the hot-pressing pressure of the present invention is within the above range, the transfer effect is better.

[0014] According to some embodiments of the present invention, in step S2, the temperature of the hot pressing is 50°C to 150°C. For example, 80°C, 100°C, 120°C, 150°C, or a sub-range composed of any values ​​can be selected.

[0015] According to some embodiments of the present invention, in step S2, the hot-pressing time is 2 min to 10 min. Too short a hot-pressing time will result in incomplete reaction and incomplete contact, while too long a hot-pressing time will result in over-reaction.

[0016] According to some embodiments of the present invention, the FAPbI3 perovskite thin film is prepared by the following method:

[0017] The FAPbI3 perovskite precursor solution is coated onto the surface of an electron transport layer containing a glass substrate and then annealed; the desired result is obtained.

[0018] According to some embodiments of the present invention, the annealing temperature is 50°C to 150°C. Therefore, when the annealing temperature is within the above range, the prepared film has high quality.

[0019] According to some embodiments of the present invention, the annealing time is 1 min to 10 min.

[0020] According to some embodiments of the present invention, the method for pre-treating the transfer medium is to treat the surface of the transfer medium with oxygen plasma. This enhances the wettability of the perovskite film and improves the quality of the perovskite film.

[0021] A bilayer perovskite thin film according to a second aspect of the present invention is prepared by the preparation method described in the first aspect of the present invention.

[0022] A third aspect of the present invention provides a perovskite solar cell comprising the bilayer perovskite thin film described in the second aspect of the present invention.

[0023] According to some embodiments of the present invention, the perovskite solar cell further includes a hole transport layer and a metal electrode sequentially disposed on the surface of a bilayer perovskite thin film.

[0024] According to some embodiments of the present invention, the material selection of the hole transport layer is not required, and any material conventionally used in the art can be used, such as spiro-OMeTAD (CAS No.: 207739-72-8), PTAA (CAS No.: 1333317-99-9), nickel oxide-based thin film, CuO or CuSCN.

[0025] According to some embodiments of the present invention, the metal electrode comprises gold, silver or copper.

[0026] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0028] Figure 1 This is a schematic diagram of the preparation process in Embodiment 1 of the present invention;

[0029] Figure 2 This is a schematic diagram illustrating the principle of the perovskite solar cell prepared according to an embodiment of the present invention;

[0030] Figure 3 This is a JV curve of the perovskite solar cell prepared by the double-layer perovskite thin film provided in Example 1 of the present invention;

[0031] Figure 4 This is the external quantum efficiency diagram of the perovskite solar cell prepared by the double-layer perovskite thin film provided in Example 1 of the present invention. Detailed Implementation

[0032] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0033] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0034] Example 1

[0035] This example provides a bilayer perovskite thin film, and its preparation process is illustrated in the schematic diagram below. Figure 1 As shown, its preparation method is as follows:

[0036] Tin-lead perovskite precursor solution: Weigh a certain molar ratio of FASnI3 (formamidinium lead tin) and MAPbI3 (methylamine lead iodide) powders, dissolve them in a mixed solvent of dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), and prepare a precursor solution with a total concentration of 1.2M, wherein FASnI3:MAPbI3 = 0.7:0.3.

[0037] Transfer medium: Polydimethylsiloxane (PDMS) was selected as the transfer medium. The PDMS surface was treated with an oxygen plasma cleaner for 10 minutes. It was then cut into thin sheets of appropriate size for later use.

[0038] Glass substrate: A cleaned indium tin oxide (ITO) conductive glass was used as the target substrate, and an electron transport layer (SnO2) was pre-deposited with a thickness of 20 nm to obtain the ITO / SnO2 substrate for later use.

[0039] S1. Fix the prepared PDMS sheet on the spin coater, add 50uL of tin-lead perovskite precursor solution, spin coat at a certain speed (3000rpm) for 30 seconds, and then pre-anneal at 100℃ for 5 minutes on a hot stage to remove some of the solvent.

[0040] Pre-annealed PDMS sheets were quickly dipped into the antisolvent chlorobenzene to induce rapid crystallization of the perovskite film. Afterward, they were removed and annealed in a dry environment (150°C, 30 minutes) to obtain a film containing (FASnI3). 0.7 (MAPbI3) 0.3 Transfer medium for perovskite thin films;

[0041] S2. A FAPbI3 perovskite film was prepared on an ITO / SnO2 substrate by spin coating and annealed on a hot plate (150℃, 10 minutes) to obtain a well-crystallized FAPbI3 film. The prepared tin-lead perovskite film was then brought into contact with the FAPbI3 film on the ITO / SnO2 substrate, and a hot press was used to transfer the film under specific temperature and pressure (120℃, 40MPa) for 5 minutes, transferring the tin-lead perovskite film from the PDMS onto the FAPbI3 film, forming a bilayer perovskite structure. The PDMS sheet was then removed, yielding a bilayer perovskite film (FAPbI3 thickness 400nm; FAPbI3). 0.7 (MAPbI3) 0.3 The thickness is 200 nm.

[0042] Example 2

[0043] This example provides a bilayer perovskite thin film, which is prepared in a manner that is basically the same as that in Example 1, except that the hot pressing pressure is 80 MPa.

[0044] Example 3

[0045] This example provides a bilayer perovskite thin film, which is prepared in a manner that is basically the same as that in Example 1, except that the hot pressing pressure is 20 MPa.

[0046] Example 4

[0047] This example provides a bilayer perovskite thin film, which is prepared in a manner that is basically the same as that in Example 1, except that the hot pressing pressure is 10 MPa.

[0048] Example 5

[0049] This example provides a bilayer perovskite thin film, which is prepared in a manner that is basically the same as that in Example 1, except that the hot pressing pressure is 100 MPa.

[0050] Example 6

[0051] This example provides a bilayer perovskite thin film, the preparation method of which is basically the same as that in Example 1, the difference being that the ratio of FASnI3:MAPbI3 is 0.4:0.6; thus, (FASnI3) is obtained. 0.4 (MAPbI3) 0.6 Perovskite thin films.

[0052] Example 7

[0053] This example provides a bilayer perovskite thin film, which is prepared in a manner that is basically the same as that in Example 1. The difference is that the transfer medium is a polyethylene terephthalate film.

[0054] Example 8

[0055] This example provides a bilayer perovskite thin film, which is prepared in a manner that is basically the same as that in Example 1, except that the hot-pressing temperature is 80°C.

[0056] Example 9

[0057] This example provides a bilayer perovskite thin film, which is prepared in a manner that is basically the same as that in Example 1, except that the hot-pressing temperature is 100°C.

[0058] Example 10

[0059] This example provides a bilayer perovskite thin film, which is prepared in a manner that is basically the same as that in Example 1, except that the hot-pressing temperature is 150°C.

[0060] Performance testing

[0061] The bilayer perovskite thin films prepared in Examples 1-10 of this invention were used to fabricate perovskite solar cells, and their schematic diagrams are shown below. Figure 2 As shown, the steps are as follows: a hole transport layer (spiro-OMeTAD; thickness 150 nm) and a silver electrode (thickness 100 nm) are sequentially deposited on the bilayer perovskite films of Examples 1-10. The photoelectric performance of the device is tested using a solar simulator, the current-voltage (JV) curve is recorded, and the photoelectric conversion efficiency is calculated. The results are shown in Table 1.

[0062] Table 1 Data from Examples 1-10

[0063] Photoelectric conversion efficiency / % Open circuit voltage / V <![CDATA[Short - circuit current / mA / cm 2 > Fill factor EQE absorption range Example 1 24.73 1.12 27.26 0.81 ~1000nm Example 2 24.06 1.11 27.10 0.80 ~1000nm Example 3 24.31 1.12 26.80 0.81 ~1000nm Example 4 16.33 1.12 23.53 0.62 ~1000nm Example 5 14.35 1.04 20.29 0.68 ~1000nm Example 6 24.52 1.12 26.70 0.82 ~1000nm Example 7 24.70 1.15 26.85 0.80 ~1000nm Example 8 23.37 1.09 27.15 0.79 ~1000nm Example 9 24.67 1.13 26.95 0.81 ~1000nm Example 10 23.21 1.12 26.57 0.78 ~1000nm

[0064] The current-voltage curve of the perovskite solar cell prepared from the bilayer perovskite thin film provided in Example 1 is shown below. Figure 3 As shown, from Figure 3 As can be seen, a photoelectric conversion efficiency of 24.73% was achieved; the open-circuit voltage was 1.12V, and the short-circuit current was 27.26mA / cm. 2 The fill factor is 0.81.

[0065] Furthermore, the external quantum efficiency of the perovskite solar cell fabricated from the bilayer perovskite thin film provided in Example 1 is as follows: Figure 4 As shown, the EQE absorbs light up to nearly 1000 nm, thus broadening the light absorption range.

[0066] As can be seen from the data in Table 1, the embodiments of the present invention prepare bilayer perovskite films using a physical transfer method with a transfer medium; this avoids the damage to the front layer perovskite film caused by chemical solution methods, thus improving the preparation quality and efficiency of the bilayer perovskite film. This is achieved by controlling (FASnI3). 1-x (MAPbI3) xThe composition of the perovskite thin film reduces the interaction force with the transfer medium, increasing its transferability. Furthermore, the bilayer perovskite thin film broadens the light absorption range of the perovskite film, improving the photoelectric conversion efficiency of solar cells fabricated from the bilayer perovskite thin film.

[0067] The present invention has been described in detail above with reference to the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for preparing a bilayer perovskite thin film, characterized in that, Includes the following steps: S1. A mixture of FASnI3 precursor solution and MAPbI3 precursor solution is coated onto the surface of a pretreated transfer medium. The mixture is then spin-coated using an anti-solvent method and annealed to obtain a solution containing (FASnI3). 1-x (MAPbI3) x Transfer medium for perovskite thin films; x is 0.1~0.6; S2, containing (FASnI3) 1-x (MAPbI3) x The perovskite film transfer medium is hot-pressed with the FAPbI3 perovskite film, and the transfer medium is removed to obtain a bilayer perovskite film. In step S2, the pressure of the hot pressing is 20 MPa to 80 MPa; the temperature of the hot pressing is 50℃ to 150℃. The FAPbI3 perovskite thin film was prepared by the following method: The FAPbI3 perovskite precursor solution is coated onto the surface of an electron transport layer containing a glass substrate and then annealed to obtain the product.

2. The method for preparing a bilayer perovskite thin film according to claim 1, characterized in that, The transfer medium is selected from at least one of polydimethylsiloxane, polyethylene terephthalate film, polyimide film, polycarbonate film, polyurethane film, silicone rubber, or hydrogel.

3. The method for preparing a bilayer perovskite thin film according to claim 1, characterized in that, The hot pressing time is 2 min to 10 min.

4. The method for preparing a bilayer perovskite thin film according to claim 1, characterized in that, The pretreatment method for the transfer medium includes: The surface of the transfer medium is treated with oxygen plasma to obtain the final product.

5. The method for preparing a bilayer perovskite thin film according to claim 1, characterized in that, The annealing temperature is 50℃~150℃.

6. The method for preparing a bilayer perovskite thin film according to claim 1, characterized in that, The annealing time is 1 min to 10 min.

7. A bilayer perovskite thin film, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 6.

8. A perovskite solar cell, characterized in that, Includes the bilayer perovskite thin film as described in claim 7.

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