Perovskite active layer, preparation method thereof and perovskite solar cell

Abstract

The invention discloses a perovskite active layer, a preparation method thereof and a perovskite solar cell, and belongs to the technical field of perovskite solar cells. The preparation method of the perovskite active layer comprises the following steps: depositing a first organic salt material on the surface of a substrate to obtain a first organic salt film layer, wherein the first organic salt material comprises an organic amine salt material; depositing an inorganic salt material on the surface of the first organic salt film layer to obtain an inorganic salt film layer; a second organic salt material is deposited on the surface of the inorganic salt film layer to obtain a second organic salt film layer, and the second organic salt material comprises an organic amine salt material, so that the part, which is difficult to participate in reaction, in the inorganic salt film layer can react with the first organic salt film layer to promote crystallization of perovskite; and the residual inorganic salt material is prevented from being in contact with a functional film such as a hole transport layer on the surface of the substrate to influence the extraction and transmission of current carriers, so that the perovskite solar cell device obtains higher short-circuit current density, and the photoelectric conversion efficiency of the device is correspondingly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cells, and in particular to a perovskite active layer and a preparation method thereof, and a perovskite solar cell. Background Art

[0002] As a new type of thin-film photovoltaic cell, perovskite solar cells have many advantages, such as high theoretical photoelectric conversion efficiency, low raw material cost, low temperature coefficient, and broad application prospects. In recent years, they have been favored by relevant personnel in academia and industry. At present, the laboratory photoelectric conversion efficiency of single-cell perovskite solar devices has exceeded 26%, which is very close to the power generation efficiency of traditional crystalline silicon photovoltaic devices. The efficiency of perovskite heterojunction stacked devices has exceeded 34%. The device structure of perovskite solar cells includes planar structure and mesoporous structure. The planar structure can be further divided into planar formal nip type and planar trans-pin type structure. The photoelectric conversion efficiency based on the trans-device has exceeded that of the formal device, and the trans-device has the advantages of low processing temperature, small hysteresis effect, and high stability. The production method based on the perovskite active layer includes one-step method, two-step method, etc., and the corresponding processing methods include dry method, wet method, etc.

[0003] At present, the high-efficiency devices based on the two-step method for preparing the active layer of perovskite solar cells all adopt a planar formal nip-type structure. There are very few high-efficiency two-step method-prepared planar inverse pin-type devices. The main reason is that when preparing the perovskite active layer based on the two-step method, a layer of inorganic salt (such as PbI2, CsI, etc.) film is usually prepared first, and then a layer of organic salt (such as FAI, MABr, etc.) film is prepared thereon, and the perovskite active layer is generated through reaction conversion. However, a major disadvantage of this way of making the active layer is that some of the inorganic salts at the bottom do not participate in the reaction and cause residues. For example, the residual PbI2 itself is a two-dimensional layered P-type semiconductor layer. Its contact with the bottom hole transport layer is actually not conducive to the extraction and transport process of carriers. Therefore, the Jsc of the finally prepared planar inverse device will be lower, resulting in low photoelectric conversion efficiency of the device. Summary of the invention

[0004] The main purpose of the present invention is to provide a perovskite active layer and a preparation method thereof and a perovskite solar cell, so as to solve the technical problem that incomplete reaction and residual raw materials are likely to occur when preparing the perovskite active layer.

[0005] To achieve the above object, the present invention provides a method for preparing a perovskite active layer, characterized in that it comprises the following steps:

[0006] Depositing a first organic salt material onto the surface of the substrate to obtain a first organic salt film layer;

[0007] Depositing an inorganic salt material onto the surface of the first organic salt film layer to obtain an inorganic salt film layer;

[0008] Depositing a second organic salt material onto the surface of the inorganic salt film layer to obtain a second organic salt film layer;

[0009] The first organic salt material includes an organic amine salt material;

[0010] The second organic salt material includes an organic amine salt material.

[0011] In some embodiments of the present invention, in the step of preparing the first organic salt film layer, the first organic salt material includes an organic amine salt material, the organic amine salt material includes at least one of FAX, MAX and DMAX, X in FAX includes at least one of I, Br and Cl, X in MAX includes at least one of I, Br and Cl, and X in DMAX includes at least one of I, Br and Cl;

[0012] and / or, in the step of preparing the inorganic salt film layer, the inorganic salt material comprises a metal halide;

[0013] And / or, in the step of preparing the second organic salt film layer, the second organic salt material includes an organic amine salt material, the organic amine salt material includes at least one of FAX, MAX and DMAX, X in FAX includes at least one of I, Br and Cl, X in MAX includes at least one of I, Br and Cl, and X in DMAX includes at least one of I, Br and Cl.

[0014] In some embodiments of the present invention, in the step of preparing the inorganic salt film layer, the inorganic salt material includes a metal halide, the metal halide includes PbX2 and CsX, X in the PbX2 includes at least one of I, Cl, and Br, and X in the CsX includes at least one of I, Cl, and Br.

[0015] In some embodiments of the present invention, in the step of preparing the first organic salt film layer, the deposition method includes thermal evaporation, spin coating, slit coating, blade coating or spray coating;

[0016] And / or, in the step of preparing the inorganic salt film layer, the deposition method includes thermal evaporation, spin coating, slit coating, blade coating or spray coating;

[0017] And / or, in the step of preparing the second organic salt film layer, the deposition method includes thermal evaporation, spin coating, slit coating, blade coating or spray coating.

[0018] In some embodiments of the present invention, in the step of preparing the first organic salt film layer, the first organic salt material is deposited on the surface of the substrate and then annealed;

[0019] And / or, in the step of preparing the inorganic salt film layer, the inorganic salt material is deposited on the surface of the first organic salt film layer and then annealed;

[0020] And / or, in the step of preparing the second organic salt film layer, the second organic salt material is deposited on the surface of the inorganic salt film layer and then annealed.

[0021] In some embodiments of the present invention, the substrate includes a hole transport film, and the first organic salt film layer is prepared on the surface of the hole transport film.

[0022] In some embodiments of the present invention, in the step of preparing the first organic film layer, the humidity range is controlled to be 30% to 50%;

[0023] And / or, in the step of preparing the inorganic salt film layer, the humidity range is controlled to be 30% to 50%;

[0024] And / or, in the step of preparing the second organic salt film layer, the humidity range is controlled to be 30% to 50%.

[0025] The present invention also provides a perovskite active layer prepared by the method for preparing a perovskite active layer as described above.

[0026] The present invention also provides a perovskite solar cell, comprising the perovskite active layer as described above.

[0027] In some embodiments of the present invention, the perovskite solar cell comprises, from bottom to top, a transparent conductive oxide layer, a hole transport layer, the perovskite active layer, an electron transport layer and a metal electrode; or,

[0028] The perovskite solar cell comprises, from bottom to top, a transparent conductive oxide layer, an electron transport layer, the perovskite active layer, a hole transport layer and a metal electrode.

[0029] The beneficial effects that can be achieved by the present invention are:

[0030] When preparing the perovskite active layer, the present invention sequentially prepares a first organic salt film layer, an inorganic salt film layer and a second organic salt film layer on the surface of a substrate to form an organic-inorganic-organic film layer structure. Compared with the inorganic-organic film layer structure in which only the inorganic salt film layer and the organic salt film layer are sequentially prepared, the organic-inorganic-organic film layer structure of the present invention can make the part of the inorganic salt film layer that is difficult to participate in the reaction react with the first organic salt film layer underneath to improve the crystallization of the perovskite, prevent the residual inorganic salt material from contacting with the functional film on the surface of the substrate, such as the hole transport layer, to affect the extraction and transport of carriers, so that the finally prepared perovskite solar cell device obtains a higher short-circuit current density, and correspondingly improves the photoelectric conversion efficiency of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0032] Figure 1 1 and 2. These are XRD signal diagrams of the perovskite active layer in the perovskite solar cells of Example 1 of the present invention and Comparative Example 1.

[0033] Figure 2 SEM images of the perovskite active layer in the perovskite solar cell of Comparative Example 1 of the present invention and Comparative Example 1, wherein control (left) and target (right).

[0034] Figure 3 It is a JV characteristic curve diagram of comparative example 1 of the present invention and the perovskite solar cell of comparative example 1.

[0035] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0036] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0039] At present, the high-efficiency devices (PCE ≥ 23%) based on the two-step method for preparing the active layer of perovskite solar cells all adopt a planar formal nip-type structure. There are very few high-efficiency two-step method-prepared planar inverse pin-type devices. The main reason is that when preparing the perovskite active layer based on the two-step method, a layer of inorganic salt (such as PbI2, CsI, etc.) film is usually prepared first, and then a layer of organic salt (such as organic amine salt material FAI, MABr, etc.) film is prepared thereon, and the perovskite active layer is generated through reaction conversion. However, there is a major disadvantage in this way of making the active layer. Some of the inorganic salts at the bottom are difficult to participate in the reaction, resulting in inorganic salt residues. For example, the residual PbI2 itself is a two-dimensional layered P-type semiconductor layer. Its contact with the bottom hole transport layer is not conducive to the extraction and transport process of carriers. Therefore, the Jsc of the finally prepared planar inverse device will be low, resulting in low photoelectric conversion efficiency of the device.

[0040] In view of this, the present invention provides a perovskite active layer and a preparation method thereof, the preparation method comprising the following steps:

[0041] S10, depositing a first organic salt material onto a surface of a substrate to obtain a first organic salt film layer, wherein the first organic salt material includes an organic amine salt material;

[0042] S20, depositing an inorganic salt material onto the surface of the first organic salt film layer to obtain an inorganic salt film layer;

[0043] S30, depositing a second organic salt material onto the surface of the inorganic salt film layer to obtain a second organic salt film layer, wherein the second organic salt material includes an organic amine salt material.

[0044] The method for preparing a perovskite active layer of the present invention belongs to a part of the method for preparing a perovskite solar cell, and therefore, can also be regarded as an improvement in the preparation process of the perovskite active layer in the method for preparing a perovskite solar cell.

[0045] When preparing the perovskite active layer, the present invention sequentially prepares a first organic salt film layer, an inorganic salt film layer and a second organic salt film layer on the surface of a substrate to form an organic-inorganic-organic film layer structure. Compared with the inorganic-organic film layer structure in which only the inorganic salt film layer and the organic salt film layer are sequentially prepared, the organic-inorganic-organic film layer structure of the present invention can make the part of the inorganic salt film layer that is difficult to participate in the reaction react with the first organic salt film layer underneath to improve the crystallization of the perovskite, prevent the residual inorganic salt material from contacting with the functional film on the surface of the substrate, such as the hole transport layer, to affect the extraction and transport of carriers, so that the finally prepared perovskite solar cell device obtains a higher short-circuit current density, and correspondingly improves the photoelectric conversion efficiency of the device.

[0046] It can be understood that the organic-inorganic-organic film layer structure refers to the film layer structure before the inorganic salt material and the first organic salt material and the second organic salt material react. When the inorganic salt material and the first organic salt material and the second organic salt material come into contact, they will react to form a perovskite film, that is, a perovskite active layer.

[0047] In the present invention, the first organic salt material and the second organic salt material both include organic amine salt materials, and the organic amine salt materials include materials commonly used in the art to prepare the perovskite active layer by a two-step method. The two-step method for preparing the perovskite active layer can be understood as a preparation process in which a metal halide film is first deposited on the surface of a substrate, and then the organic amine salt material is dissolved and applied to the metal halide film, so that it reacts chemically with the metal halide to form a perovskite film.

[0048] Therefore, in some embodiments, the first organic salt material includes an organic amine salt material, and the organic amine salt material includes at least one of FAX, MAX and DMAX, and X in FAX includes at least one of I, Br and Cl, that is, FAX includes at least one of formamidine hydroiodide (FAI), formamidine hydrobromide (FABr) and formamidine hydrochloride (FACl); X in MAX includes at least one of I, Br and Cl, that is, MAX includes at least one of methylammonium iodide (MAI), methylammonium bromide (MABr) and methylammonium chloride (MACl); X in DMAX includes at least one of I, Br and Cl, that is, DMAX includes at least one of dimethylammonium iodide (DMAI), dimethylammonium bromide (DMABr) and dimethylammonium chloride (DMACl). The above types of organic amine salt materials can react chemically with the inorganic salt materials in the inorganic salt film layer, promote the crystallization of perovskite, reduce the residue of inorganic salt materials, and promote the extraction and transmission of carriers, so that the finally prepared perovskite solar cell device obtains a higher short-circuit current density, and correspondingly improves the photoelectric conversion efficiency of the device.

[0049] In some embodiments, the second organic salt material includes an organic amine salt material, and the organic amine salt material includes at least one of FAX, MAX and DMAX, and X in FAX includes at least one of I, Br and Cl, that is, FAX includes at least one of formamidine hydroiodide (FAI), formamidine hydrobromide (FABr) and formamidine hydrochloride (FACl); X in MAX includes at least one of I, Br and Cl, that is, MAX includes at least one of methylammonium iodide (MAI), methylammonium bromide (MABr) and methylammonium chloride (MACl); X in DMAX includes at least one of I, Br and Cl, that is, DMAX includes at least one of dimethylammonium iodide (DMAI), dimethylammonium bromide (DMABr) and dimethylammonium chloride (DMACl). The above types of organic amine salt materials can react chemically with the inorganic salt materials in the inorganic salt film layer, promote the crystallization of perovskite, reduce the residue of inorganic salt materials, and promote the extraction and transmission of carriers, so that the finally prepared perovskite solar cell device obtains a higher short-circuit current density, and correspondingly improves the photoelectric conversion efficiency of the device.

[0050] In some embodiments, the first organic salt material is FAI, and the second organic salt material includes FAI and at least one of MABr and MACl. The first organic salt material is FAI, which is beneficial to promote the reaction of the inorganic salt material in the lower layer of the inorganic salt film layer and promote the crystallization of perovskite.

[0051] In some embodiments, in the step of preparing the inorganic salt film layer, the inorganic salt material includes a metal halide. In this embodiment, the metal halide can chemically react with the first organic salt material and the second organic salt material to promote the formation of the perovskite film.

[0052] In some embodiments, the metal halide includes at least one of PbX2 and CsX, and X in PbX2 includes at least one of I, Br, and Cl, that is, PbX2 includes at least one of lead iodide (PbI2), lead bromide (PbBr2), and lead chloride (PbCl2); X in CsX includes at least one of I, Br, and Cl, that is, CsX includes at least one of cesium iodide (CsI), cesium bromide (CsBr), and cesium chloride (CsCl). The above metal halides can react chemically with the first organic salt material and the second organic salt material to promote the formation of perovskite film.

[0053] In the step of preparing the first organic salt film layer, the deposition method includes thermal evaporation, spin coating, slit coating, blade coating or spray coating.

[0054] In some embodiments, the first organic salt material is deposited onto the surface of the substrate by spin coating to prepare the first organic salt film layer. Preferably, the process conditions of the spin coating method include: a spin coating speed of 1500 rpm to 4000 rpm, a spin coating time of 25 s to 35 s, and a spin coating acceleration of 1500 rpm / s to 4000 rpm / s. In this embodiment, the first organic salt film layer of the desired thickness can be obtained by controlling the spin coating conditions.

[0055] In some embodiments, the first organic salt material can be dissolved in an organic solvent to obtain a first organic salt solution, and then the first organic salt solution is spin-coated onto the surface of the substrate to prepare the first organic salt film layer. In this embodiment, the organic solvent includes at least one of dimethylformamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone.

[0056] In some embodiments, the concentration of the first organic salt material in the first organic salt solution is 50 mg / mL to 100 mg / mL.

[0057] In some embodiments, after the first organic salt solution is spin-coated onto the surface of the substrate, it is further subjected to annealing treatment. Preferably, the annealing conditions include: an annealing temperature of 80° C. to 150° C., and an annealing time of 5 min to 30 min.

[0058] In the step of preparing the inorganic salt film layer, the deposition method includes thermal evaporation, spin coating, slit coating, blade coating or spray coating.

[0059] In some embodiments, the inorganic salt film layer is prepared by depositing the inorganic salt material onto the surface of the first organic salt film layer by spin coating. Preferably, the process conditions of the spin coating method include: a spin coating speed of 1500 rpm to 4000 rpm, a spin coating time of 25 s to 35 s, and a spin coating acceleration of 1500 rpm / s to 4000 rpm / s. In this embodiment, the inorganic salt film layer of the desired thickness can be obtained by controlling the spin coating conditions.

[0060] In some embodiments, the inorganic salt material can be dissolved in an organic solvent to obtain an inorganic salt solution, and then the inorganic salt solution can be spin-coated onto the surface of the first organic salt film layer to prepare the inorganic salt film layer. In this embodiment, the organic solvent can refer to the commonly used solvents in the art, preferably, including at least one of dimethylformamide, dimethyl sulfoxide and N-methyl-2-pyrrolidone.

[0061] In some embodiments, the concentration of the inorganic salt material in the inorganic salt solution is 0.8-2.0 mol / L.

[0062] In some embodiments, the inorganic salt solution is spin-coated onto the surface of the first organic salt film layer and then annealed. Preferably, the annealing conditions include: an annealing temperature of 70° C. to 100° C. and an annealing time of 1 min to 5 min.

[0063] In the step of preparing the second organic salt film layer, the deposition method includes thermal evaporation, spin coating, slit coating, blade coating or spray coating.

[0064] In some embodiments, the second organic salt film layer is prepared by depositing the second organic salt material onto the surface of the inorganic salt film layer by spin coating. Preferably, the process conditions of the spin coating method include: a spin coating speed of 1500 rpm to 3000 rpm, for example, 2000 rpm; a spin coating time of 20 to 40 s, for example, 30 s; and a spin coating acceleration of 1500 to 3000 rpm / s, for example, 2000 rpm / s. In this embodiment, the second organic salt film layer of the desired thickness can be obtained by controlling the spin coating conditions.

[0065] In some embodiments, the second organic salt material can be dissolved in an organic solvent to obtain a second organic salt solution, and then the second organic salt solution can be spin-coated onto the surface of the substrate to prepare a second organic salt film layer. In this embodiment, the organic solvent can refer to the commonly used solvents in the art, preferably, including at least one of dimethylformamide, dimethyl sulfoxide and N-methyl-2-pyrrolidone.

[0066] In some embodiments, the concentration of the second organic salt material in the second organic salt solution is 50 mg / mL to 100 mg / mL.

[0067] In some embodiments, after the second organic salt solution is spin-coated onto the surface of the inorganic salt film layer, it is also subjected to annealing treatment. Preferably, the annealing conditions include: an annealing temperature of 130-170°C, such as 150°C, and an annealing time of 10-30 minutes, such as 15 minutes.

[0068] In the present invention, the substrate includes a hole transport layer film, and a perovskite active layer is prepared on the surface of the hole transport layer. In the art, a two-step method is usually used to prepare a perovskite active layer on the surface of the hole transport layer. For example, a metal halide film is first prepared on the surface of the hole transport film, and then an organic amine salt material is deposited on the surface of the metal halide film. In this way, the metal halide in the lower layer of the metal halide film is difficult to react with the organic amine salt material, and residue will appear, affecting the extraction and transmission of carriers. In the present invention, a first organic salt film layer is first prepared on the surface of the hole transport film, and then an inorganic salt film layer and a second organic salt film layer are deposited in sequence. In this way, the first organic salt material in the first organic salt film layer can then react with the inorganic salt material under the inorganic salt film layer to promote the crystallization of perovskite, reduce the residual inorganic salt, and facilitate the extraction and transmission of carriers, so that the finally prepared perovskite solar cell device can obtain a higher short-circuit current density, and correspondingly improve the photoelectric conversion efficiency of the device.

[0069] In some embodiments, when preparing the first organic film layer, the humidity range is controlled to be 30% to 50%, which is beneficial to promoting the growth of perovskite crystals and improving the crystallization quality of perovskite.

[0070] In some embodiments, in the step of preparing the inorganic salt film layer, the humidity range is controlled to be 30% to 50%, which is beneficial to promoting the growth of perovskite crystals and improving the crystallization quality of perovskite.

[0071] In some embodiments, in the step of preparing the second organic salt film layer, the humidity range is controlled to be 30% to 50%, which is beneficial to promoting the growth of perovskite crystals and improving the crystallization quality of perovskite.

[0072] The present invention also provides a perovskite solar cell, which includes the perovskite active layer provided by the present invention as described above, and at least has all the beneficial effects brought by the above perovskite active layer, which will not be described in detail here.

[0073] In some embodiments, the perovskite solar cell of the present invention includes an inverted perovskite cell, which includes, from bottom to top, a transparent conductive oxide layer, a hole transport layer, a perovskite active layer prepared by the present invention, an electron transport layer, and a metal electrode.

[0074] In some embodiments, an interface modification layer commonly used in the art is also included between the transparent conductive oxide layer and the hole transport layer, between the hole transport layer and the perovskite active layer, between the perovskite active layer and the electron transport layer, and between the electron transport layer and the metal electrode, which has the effect of improving the interface contact, including but not limited to. Preferably, a passivation layer is provided between the electron transport layer and the metal electrode, and the passivation layer includes 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), which can improve the interface contact and passivate the surface defects, thereby improving the stability of the perovskite solar cell.

[0075] In some embodiments, the perovskite solar cell of the present invention further comprises an upright perovskite cell, which comprises, from bottom to top, a transparent conductive oxide layer, an electron transport layer, the perovskite active layer, a hole transport layer and a metal electrode. In this embodiment, the deposition method of the perovskite active layer can refer to the commonly used technical means of the upright perovskite active layer in the art.

[0076] In some embodiments, an interface modification layer commonly used in the art is provided between the transparent conductive oxide layer and the electron transport layer, between the electron transport layer and the perovskite active layer, between the perovskite active layer and the hole transport layer, and between the hole transport layer and the metal electrode, which has the effect of including but not limited to improving the interface contact.

[0077] In the present invention, the preparation of the transparent conductive oxide layer, the electron transport layer, the hole transport layer, and the metal electrode can all refer to the preparation methods well known in the art.

[0078] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following specific embodiments are only used to explain the present invention, and are not used to limit the present invention.

[0079] Example 1

[0080] The preparation method of the perovskite solar cell of Example 1 is as follows:

[0081] Preparation of hole transport layer

[0082] Nickel oxide nanoparticles were weighed according to the mass concentration and dissolved in deionized water to obtain a nickel oxide solution with a mass concentration of 20 mg / mL. After ultrasonic oscillation for 15 minutes and filtration, the solution was spin-coated on a clean ITO glass substrate with spin coating parameters of 3000 rpm, 30 seconds, and 1500 rpm / s. The solution was then placed on a heated substrate at 200°C for thermal annealing for 10 minutes to obtain an ITO glass substrate with a NiOx film layer.

[0083] Preparation of perovskite active layer

[0084] Prepare the first organic salt film layer: weigh the FAI drug, dissolve it in the IPA solvent to obtain a FAI solution with a mass concentration of 50 mg / mL, filter the FAI solution in a N2 glove box and spin-coat it on the above-mentioned NiOx film layer. The spin-coating parameters are 1500 rpm, 30 s, and 1500 rpm / s. Then place it on a heated substrate at 100°C for heat treatment for 5 min and set it aside.

[0085] Preparation of inorganic salt film layer: PbI2 drug was weighed and dissolved in a mixed solvent of DMF:DMSO=9:1 (v / v) to obtain a PbI2 solution with a concentration of 1.5 mol / L. After filtering in a N2 glove box, the PbI2 solution was spin-coated on the surface of the first organic salt film layer with spin-coating parameters of 1500 rpm, 30 s, and 1500 rpm / s. The mixture was then placed on a heated substrate at 70°C for heat treatment for 1 min and set aside.

[0086] Preparation of the second organic salt film layer: weigh 90 mg of FAI drug and 9 mg of MACl drug, mix and dissolve in 1 mL of IPA solvent, filter in a N2 glove box and spin coat it on the surface of the inorganic salt film layer. The spin coating parameters are 2000 rpm, 30 s, and 2000 rpm / s. Then take out the ITO substrate and place it on a 150°C heating substrate for heat treatment for 15 minutes. The air environment humidity atmosphere is controlled between 30% and 50% RH to obtain a perovskite active layer.

[0087] Preparation of electron transport film

[0088] The above-mentioned ITO substrate containing the perovskite active layer is transferred to the organic salt material evaporation chamber and then C 60 Preparation of BCP film, control C 60 The evaporation rate of is not higher than 0.1A / s, and the film thickness is 25nm. The evaporation rate of BCP is not higher than 0.1A / s, and the film thickness is 8nm.

[0089] Preparation of back electrode film layer: Based on the above substrate, it is transferred to a metal material evaporation chamber to prepare the back electrode Cu, the evaporation rate is not higher than 2A / s, and the film thickness is 100nm, thereby obtaining a perovskite solar cell device.

[0090] Example 2

[0091] Example 2 A perovskite solar cell device was prepared by referring to the preparation method of Example 1, except that, in Example 2, when preparing the first organic film layer, FACl of equal concentration was used instead of FAI.

[0092] Example 3

[0093] Example 3 A perovskite solar cell device was prepared by referring to the preparation method of Example 1, except that, in Example 2, when preparing the second organic film layer, 90 mg of MABr and 9 mg of DMACl replaced 90 mg of FAI and 9 mg of MACl.

[0094] Example 4

[0095] Example 4 A perovskite solar cell device was prepared by referring to the preparation method of Example 1, except that, in Example 4, CsI of equal concentration was used instead of PbI2 when preparing the inorganic salt film layer.

[0096] Example 5

[0097] Example 5 A perovskite solar cell device was prepared by referring to the preparation method of Example 1, except that, in Example 5, MABr of equal concentration was used instead of FAI when preparing the first organic film layer.

[0098] Comparative Example 1

[0099] Comparative Example 1 A perovskite solar cell device was prepared by referring to the preparation method of Example 1, except that the first organic salt film layer was not prepared in Comparative Example 1, and the inorganic salt film layer and the second organic salt film layer in Example 1 were prepared directly on the surface of the hole transport layer to obtain a perovskite active layer.

[0100] Performance Testing

[0101] 1. Determine the XRD signal diagram of the corresponding perovskite active layer in Example 1 and Comparative Example 1. The results are as follows: Figure 1 As shown, Example 1 is represented by target and Comparative Example 1 is represented by control.

[0102] 2. The perovskite active layers in the devices of Example 1 and Comparative Example 1 were observed using a scanning electron microscope. The results are as follows: Figure 2 As shown, Example 1 is represented by target and Comparative Example 1 is represented by control.

[0103] 3. Use a solar simulator at 100mw / cm 2 The performance of the perovskite solar cells prepared in Examples 1 to 5 and Comparative Example 1 was tested under a standard light intensity of , and the data are shown in Tables 1 and Figure 3 , Figure 3 The JV characteristic curve comparison diagram of Example 1 and Comparative Example 1 is shown. Figure 3 In the figure, the data of comparative example 1 are represented by control, and the data of embodiment 1 are represented by target.

[0104] Table 1

[0105]

[0106]

[0107] Depend on Figure 1 It can be seen that the signal intensity of the characteristic peak of PbI2 at about 12.7° of the perovskite film based on Example 1 is significantly weakened, indicating that the organic-inorganic-organic structure of the perovskite film of the present invention can effectively improve the residual phenomenon of PbI2 at the bottom that has not fully participated in the reaction.

[0108] Depend on Figure 2 It can be seen that the white crystalline PbI2 shown based on the surface morphology of the perovskite film of Example 1 is also significantly less than that of Comparative Example 1, which also shows that the organic-inorganic-organic structure of the perovskite film of the present invention can further improve the reaction between PbI2 and organic salts.

[0109] Combination Figure 3 As can be seen from Table 1, the perovskite active layer in the perovskite solar cells of Examples 1 to 5 is prepared in sequence by preparing a first organic salt film layer, an inorganic salt film layer and a second organic salt film layer to form an organic-inorganic-organic film structure. Compared with the inorganic-organic film structure of Comparative Example 1 in which only an inorganic salt film layer and an organic salt film layer are prepared in sequence, the inorganic salt material PbI2 in the first organic film layer and the inorganic salt film layer reacts, which reduces the residual PbI2 and promotes the extraction and transmission of carriers, so that the perovskite solar cell obtains a better photoelectric conversion efficiency.

[0110] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a perovskite active layer, characterized in that: The following steps are involved: Depositing a first organic salt material onto the surface of the substrate to obtain a first organic salt film layer; Depositing an inorganic salt material onto the surface of the first organic salt film layer to obtain an inorganic salt film layer; Depositing a second organic salt material onto the surface of the inorganic salt film layer to obtain a second organic salt film layer; The first organic salt material includes an organic amine salt material; The second organic salt material includes an organic amine salt material.

2. The method for preparing the perovskite active layer according to claim 1, characterized in that: In the step of preparing the first organic salt film layer, the first organic salt material includes an organic amine salt material, the organic amine salt material includes at least one of FAX, MAX and DMAX, X in FAX includes at least one of I, Br and Cl, X in MAX includes at least one of I, Br and Cl, and X in DMAX includes at least one of I, Br and Cl; and / or, in the step of preparing the inorganic salt film layer, the inorganic salt material comprises a metal halide; And / or, in the step of preparing the second organic salt film layer, the second organic salt material includes an organic amine salt material, the organic amine salt material includes at least one of FAX, MAX and DMAX, X in FAX includes at least one of I, Br and Cl, X in MAX includes at least one of I, Br and Cl, and X in DMAX includes at least one of I, Br and Cl.

3. The method for preparing a perovskite active layer according to claim 2, characterized in that: In the step of preparing the inorganic salt film layer, the inorganic salt material includes metal halide, the metal halide includes PbX2 and CsX, X in the PbX2 includes at least one of I, Cl, and Br, and X in the CsX includes at least one of I, Cl, and Br.

4. The method for preparing a perovskite active layer according to claim 1, characterized in that: In the step of preparing the first organic salt film layer, the deposition method includes thermal evaporation, spin coating, slit coating, blade coating or spray coating; And / or, in the step of preparing the inorganic salt film layer, the deposition method includes thermal evaporation, spin coating, slit coating, blade coating or spray coating; And / or, in the step of preparing the second organic salt film layer, the deposition method includes thermal evaporation, spin coating, slit coating, blade coating or spray coating.

5. The method for preparing a perovskite active layer according to claim 1, characterized in that: In the step of preparing the first organic salt film layer, the first organic salt material is deposited on the surface of the substrate and then annealed; And / or, in the step of preparing the inorganic salt film layer, the inorganic salt material is deposited on the surface of the first organic salt film layer and then annealed; And / or, in the step of preparing the second organic salt film layer, the second organic salt material is deposited on the surface of the inorganic salt film layer and then annealed.

6. The method for preparing a perovskite active layer according to claim 1, characterized in that: The substrate comprises a hole transport film, and the first organic salt film layer is prepared on the surface of the hole transport film.

7. The method for preparing a perovskite active layer according to any one of claims 1 to 6, characterized in that: In the step of preparing the first organic film layer, the humidity range is controlled to be 30% to 50%; And / or, in the step of preparing the inorganic salt film layer, the humidity range is controlled to be 30% to 50%; And / or, in the step of preparing the second organic salt film layer, the humidity range is controlled to be 30% to 50%.

8. A perovskite active layer prepared by the method for preparing a perovskite active layer according to any one of claims 1 to 7.

9. A perovskite solar cell, characterized in that: Comprising the perovskite active layer as claimed in claim 8.

10. The perovskite solar cell according to claim 9, characterized in that: The perovskite solar cell comprises, from bottom to top, a transparent conductive oxide layer, a hole transport layer, the perovskite active layer, an electron transport layer and a metal electrode; or, The perovskite solar cell comprises, from bottom to top, a transparent conductive oxide layer, an electron transport layer, the perovskite active layer, a hole transport layer and a metal electrode.

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