Perovskite thin film, perovskite battery and preparation method thereof

Abstract

The invention discloses a perovskite thin film, a perovskite cell and a preparation method thereof, and is applied to the technical field of perovskite solar cells, and the perovskite thin film comprises a perovskite light absorption layer and a perovskite passivation layer located on the surface of one side of the perovskite light absorption layer; the perovskite passivation layer is made of an all-inorganic material; the band gap of the perovskite light absorption layer is smaller than the band gap of the perovskite passivation layer. The perovskite passivation layer made of an all-inorganic material can be prepared on the surface of the perovskite light absorption layer through the evaporation method, and the method has the advantages that the method is environmentally friendly, solvent-free, easy to prepare and capable of being produced in batches, the obtained thin film is good in morphology, and the perovskite light absorption layer below cannot be eroded.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of perovskite solar cells, in particular to a perovskite thin film, a preparation method of the perovskite thin film, a perovskite cell and a preparation method of the perovskite cell. BACKGROUND

[0002] Perovskite solar cells have become one of the research focuses due to their high efficiency, low cost and adjustable band gap. The full perovskite tandem cell can significantly improve the spectral utilization of sunlight and thus improve the conversion efficiency of the cell by combining a wide band gap perovskite material with a narrow band gap perovskite material. In the full perovskite tandem cell, a tin-based perovskite or a tin-lead perovskite is selected as the bottom cell of the full perovskite tandem cell. However, the tin-based perovskite and the tin-lead perovskite have the problems of large voltage loss and low fill factor, resulting in low efficiency. This is mainly due to the non-radiative recombination occurring at the interface between the light absorbing layer of the tin-based perovskite and the electron transport layer. At present, a 3D or 2D perovskite passivation layer can be prepared on the tin-based perovskite and the tin-lead perovskite to reduce the interface defects and improve the cell efficiency. The requirement for the perovskite passivation layer is that the band gap thereof needs to be greater than that of the perovskite light absorbing layer.

[0003] In the prior art, a perovskite light absorbing layer is first prepared, and then a perovskite passivation layer is deposited on the light absorbing layer. The perovskite passivation layer currently used is an organic / inorganic hybrid perovskite. The inorganic salt can be prepared by evaporation, but the organic salt part must use the solution method. The preparation of the perovskite passivation layer on the perovskite light absorbing layer by the solution method will lead to the dissolution of part of the perovskite light absorbing layer, thereby reducing the efficiency. At the same time, due to the high vapor pressure of the organic salt components such as methylammonium iodide and formamidinium iodide, it is difficult to stably control the evaporation rate of these organic salts in the evaporation preparation process, so the organic salt is also not suitable for preparation by evaporation. Therefore, how to provide a perovskite thin film that can be prepared by evaporation is a technical problem that those skilled in the art urgently need to solve. SUMMARY

[0004] The purpose of the present application is to provide a perovskite thin film that can be prepared by evaporation. Another purpose of the present application is to provide a preparation method of the perovskite thin film, a perovskite cell and a preparation method of the perovskite cell, which can be prepared by evaporation.

[0005] To solve the above technical problems, the present application provides a perovskite thin film, which comprises a perovskite light absorbing layer and a perovskite passivation layer located on one side surface of the perovskite light absorbing layer. The material of the perovskite passivation layer is a full inorganic material. The band gap of the perovskite light absorbing layer is smaller than that of the perovskite passivation layer.

[0006] Optionally, the perovskite light-absorbing layer is ABX3, wherein A is a combination of one or more of MA + , FA + , and Cs + ; B is a combination of one or more of Pb 2+ and Sn 2+ ; and X is a combination of one or more of Cl - , Br - , and I - .

[0007] The perovskite passivation layer is A’B’X’3, wherein A’ is Cs + ; B’ is a combination of one or more of Pb 2+ and Sn 2+ ; and X’ is a combination of one or more of Cl - , Br - , and I - .

[0008] Optionally, the perovskite passivation layer has B’ of Pb 2+ ; and X’ of Br - , I - .

[0009] Optionally, the perovskite light-absorbing layer has a thickness of 400 nm to 2500 nm.

[0010] Optionally, the perovskite passivation layer has a thickness of 10 nm to 40 nm.

[0011] The application also provides a preparation method of a perovskite thin film, comprising:

[0012] providing a perovskite light-absorbing layer on a surface of a substrate;

[0013] providing a perovskite passivation layer on a surface of the perovskite light-absorbing layer based on an evaporation method; the material of the perovskite passivation layer is a full inorganic material, and the band gap of the perovskite light-absorbing layer is smaller than the band gap of the perovskite passivation layer.

[0014] Optionally, the perovskite light-absorbing layer is ABX3, wherein A is a combination of one or more of MA + , FA + , and Cs + ; B is a combination of one or more of Pb 2+ and Sn 2+ ; and X is a combination of one or more of Cl - , Br - , and I - .

[0015] The perovskite passivation layer is A'B'X'3, A' is Cs + ; B' is a combination of one or more of Pb 2+ or Sn 2+ ; X' is a combination of one or more of Cl - , Br - , I - .

[0016] Optionally, the perovskite light-absorbing layer on the surface of the substrate comprises:

[0017] The perovskite light-absorbing layer is set on the surface of the substrate based on an evaporation method.

[0018] Optionally, the perovskite light-absorbing layer is set on the surface of the substrate based on an evaporation method, comprising:

[0019] The substrate is transferred into a vacuum chamber of a vacuum coating machine, a plurality of coating materials are placed into corresponding evaporation boats, and the evaporation boats are placed in the vacuum chamber;

[0020] The perovskite light-absorbing layer is evaporated on the surface of the substrate at a preset rate by the vacuum coating machine;

[0021] The perovskite passivation layer is set on the surface of the perovskite light-absorbing layer based on an evaporation method, comprising:

[0022] The perovskite passivation layer is evaporated on the surface of the perovskite light-absorbing layer at a preset rate by the vacuum coating machine.

[0023] Optionally, before the perovskite passivation layer is evaporated on the surface of the perovskite light-absorbing layer at a preset rate, the method further comprises:

[0024] The substrate provided with the perovskite light-absorbing layer is annealed;

[0025] After the perovskite passivation layer is evaporated on the surface of the perovskite light-absorbing layer at a preset rate, the method further comprises:

[0026] The perovskite thin film is annealed.

[0027] The application further provides a perovskite battery, comprising:

[0028] A conductive substrate;

[0029] A hole transport layer on one side surface of the conductive substrate;

[0030] A perovskite thin film on the side surface of the hole transport layer away from the conductive substrate; the perovskite thin film is the perovskite thin film according to any one of the above; the hole transport layer is in contact with the perovskite light-absorbing layer;

[0031] An electron transport layer is prepared on the surface of the perovskite passivation layer away from the conductive substrate;

[0032] An electrode is prepared on the surface of the electron transport layer away from the conductive substrate.

[0033] The application further provides a preparation method of the perovskite battery, comprising:

[0034] A hole transport layer is prepared on the surface of the conductive substrate;

[0035] A perovskite thin film is prepared on the surface of the hole transport layer; the preparation method of the perovskite thin film is the preparation method of the perovskite thin film according to any one of the above aspects; the substrate is the conductive substrate provided with the hole transport layer, and the hole transport layer is in contact with the perovskite light-absorbing layer;

[0036] An electron transport layer is prepared on the surface of the perovskite passivation layer;

[0037] An electrode is prepared on the surface of the electron transport layer.

[0038] The perovskite thin film provided by the application comprises a perovskite light-absorbing layer and a perovskite passivation layer on the surface of the perovskite light-absorbing layer; the material of the perovskite passivation layer is a full-inorganic material; and the band gap of the perovskite light-absorbing layer is smaller than that of the perovskite passivation layer.

[0039] The perovskite passivation layer with a full-inorganic material on the surface of the perovskite light-absorbing layer can be prepared by an evaporation method, which has the advantages of environmental friendliness, no solvent, easy preparation, batch production, good film morphology, and no erosion of the underlying perovskite light-absorbing layer.

[0040] The application further provides a preparation method of the perovskite thin film, a perovskite battery and a preparation method of the perovskite battery, which also have the above beneficial effects, and will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only constitute some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0042] Figure 1 The structure of the perovskite thin film provided by the embodiments of the application is shown in the schematic view.

[0043] Figure 2 The process flow chart of the preparation method of the perovskite thin film provided by the embodiments of the application is shown in the schematic view.

[0044] Figure 3 The emission spectrum of the perovskite light-absorbing layer without a passivation layer and the perovskite light-absorbing layer with a passivation layer;

[0045] Figure 4 A structure schematic diagram of a perovskite battery provided by an embodiment of the present application;

[0046] Figure 5 A process flow chart of a perovskite battery preparation method provided by an embodiment of the present application.

[0047] In the figure: 1. perovskite light-absorbing layer, 2. perovskite passivation layer, 3. conductive substrate, 4. hole transport layer, 5. electron transport layer, 6. electrode. DETAILED DESCRIPTION

[0048] The core of the present application is to provide a perovskite thin film. In the prior art, a perovskite light-absorbing layer is first prepared, and then a perovskite passivation layer is deposited on the light-absorbing layer. The perovskite passivation layer currently used is an organic / inorganic hybrid perovskite. The inorganic salt can be prepared by evaporation, but the organic salt part must use a solution method. Preparing a perovskite passivation layer on a perovskite light-absorbing layer by a solution method will cause partial dissolution of the perovskite light-absorbing layer, thereby reducing the efficiency. At the same time, due to the high vapor pressure of organic salt components such as methylammonium iodide and formamidinium iodide, it is difficult to stably control the evaporation rate of these organic salts during the evaporation preparation process, so the organic salt is also not suitable for evaporation preparation.

[0049] The perovskite thin film provided by the present application includes a perovskite light-absorbing layer and a perovskite passivation layer located on one side surface of the perovskite light-absorbing layer. The material of the perovskite passivation layer is a full inorganic material. The band gap of the perovskite light-absorbing layer is smaller than that of the perovskite passivation layer.

[0050] The perovskite passivation layer with a full inorganic material on the surface of the perovskite light-absorbing layer can be prepared by an evaporation method, which has the advantages of environmental friendliness, no solvent, easy preparation, batch production, good film morphology, and no erosion of the underlying perovskite light-absorbing layer.

[0051] In order for those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0052] Please refer to Figure 1 , Figure 1A structural schematic diagram of a perovskite film provided in an embodiment of the present application.

[0053] Referring to Figure 1 In the embodiment of the present application, the perovskite film comprises a perovskite light-absorbing layer 1 and a perovskite passivation layer 2 located on one side surface of the perovskite light-absorbing layer 1; the material of the perovskite passivation layer 2 is a full inorganic material, the perovskite passivation layer 2 is a passivation layer prepared on the surface of the perovskite light-absorbing layer 1 based on an evaporation method; the band gap of the perovskite light-absorbing layer 1 is smaller than that of the perovskite passivation layer 2.

[0054] In the embodiment, the material of the perovskite passivation layer 2 is a full inorganic material, that is, there is no organic component in the composition of the perovskite passivation layer 2, and the perovskite passivation layer 2 is completely formed of inorganic materials. Therefore, in the embodiment, the perovskite passivation layer 2 can be a passivation layer prepared on the surface of the perovskite light-absorbing layer 1 based on an evaporation method. The principle of the evaporation method is generally to heat the material target to an evaporation state in a vacuum chamber to form a vapor stream, and then the vapor stream collides and condenses on the surface of the part to be plated, so as to form a solid thin film on the substrate. Obviously, this process has a limitation for the material of the finally formed thin film, and it is generally only suitable for the preparation of inorganic material thin film, and it is generally not possible to prepare an organic material thin film by the evaporation method. Since the perovskite passivation layer 2 of the embodiment is a pure inorganic perovskite structure, it can be prepared on the surface of the perovskite light-absorbing layer 1 based on the evaporation method.

[0055] Specifically, in the embodiment, the perovskite light-absorbing layer 1 can be ABX3, the A is one or a combination of MA + , FA + , and Cs + ; the B is one or a combination of Pb 2+ or Sn 2+ ; the X is one or a combination of Cl - , Br - , and I - ; the perovskite passivation layer 2 is A’B’X’3, the A’ is Cs + ; the B’ is one or a combination of Pb 2+ or Sn 2+ ; and the X’ is one or a combination of Cl - , Br - , and I - .

[0056] The perovskite light-absorbing layer 1 described above is mainly used for absorbing light and converting light energy into electrical energy. In the embodiment, the component of the perovskite light-absorbing layer 1 is ABX3, the A is MA + , FA + , and Cs+ one or more of the following: Sn 2+ one or more of the following: Sn 2+ one or more of the following: Cl - one or more of the following: Br - one or more of the following: I - one or more of the following: Cl

[0057] The perovskite passivation layer 2 is located on one side surface of the perovskite light-absorbing layer 1, and in the perovskite battery, the perovskite passivation layer 2 is specifically located between the perovskite light-absorbing layer 1 and the electron transport layer 5, for reducing interface defects and improving battery efficiency. In the embodiment, the perovskite passivation layer 2 is A'B'X'3, which has a structure similar to that of the perovskite light-absorbing layer 1 ABX3, but the specific component types used are different. In the embodiment, A' in the perovskite passivation layer 2 A'B'X'3 is Cs + ; B' is Pb 2+ or Sn 2+ one or more of the following: Cl - one or more of the following: Br - one or more of the following: I - one or more of the following: Cl In the embodiment, the first requirement is that the band gap of the perovskite light-absorbing layer 1 is smaller than that of the perovskite passivation layer 2, so as to form a combination of wide-bandgap perovskite material and narrow-bandgap perovskite material, so that the perovskite thin film of the embodiment has a high utilization rate for the spectrum of sunlight. A significant advantage of perovskite material is that the band gap is adjustable, so in the embodiment, the band gap of the perovskite light-absorbing layer 1 can be smaller than that of the perovskite passivation layer 2.

[0058] Based on the specific components of the perovskite passivation layer 2 A'B'X'3, it is specifically a pure inorganic perovskite structure, so it can be prepared on the surface of the perovskite light-absorbing layer 1 based on the evaporation method. The specific content of the evaporation method will be described in detail in the following inventive embodiment, and will not be described here.

[0059] Specifically, in the embodiment, B' of the perovskite passivation layer 2 is preferably Pb 2+ ; X' is preferably one or more of the following: Br - one or more of the following: I - one or more of the following: Cl Correspondingly, the perovskite light-absorbing layer in the embodiment can also be prepared by the evaporation method, and correspondingly, the material of the perovskite light-absorbing layer 1 needs to be selected to be suitable for the evaporation method, for example, A in the perovskite light-absorbing layer 1 ABX3 can be Cs + ; B is Pb2+ or Sn 2+ in combination; the X is Cl - , Br - , I - in combination.

[0060] Specifically, in the present embodiment, the thickness of the perovskite light-absorbing layer 1 is generally 400 nm to 2500 nm, inclusive; and the thickness of the perovskite passivation layer 2 is generally 10 nm to 40 nm, inclusive.

[0061] The perovskite thin film provided by the present embodiment can be prepared on the surface of the perovskite light-absorbing layer 1 by a vapor deposition method, and has the advantages of environmental friendliness, no solvent, easy preparation, batch production, good film morphology, and no erosion of the underlying perovskite light-absorbing layer 1.

[0062] The preparation method of the perovskite thin film provided by the present embodiment is described below. The preparation method of the perovskite thin film described below can be referred to in conjunction with the perovskite thin film described above.

[0063] Please refer to Figure 2 and Figure 3 , Figure 2 for the process flow chart of the preparation method of the perovskite thin film provided by the present embodiment. Figure 3 for the emission spectrum of the perovskite light-absorbing layer 1 without a passivation layer and the perovskite light-absorbing layer 1 with a passivation layer.

[0064] Referring to Figure 2 , in the present embodiment, the preparation method of the perovskite thin film comprises:

[0065] S101: disposing a perovskite light-absorbing layer on the surface of a substrate.

[0066] Specifically, in the present embodiment, the perovskite light-absorbing layer 1 can be ABX3, wherein A is one or more combinations of MA + , FA + , Cs + ; B is one or more combinations of Pb 2+ or Sn 2+ ; and X is one or more combinations of Cl - , Br - , I - . The specific components of the perovskite light-absorbing layer 1 have been described in detail in the above embodiment, and will not be repeated here.

[0067] The substrate can be a conventional substrate used in experiments, such as conductive glass, etc. The substrate can also be a film structure arranged between perovskite light-absorbing layers 1 in a perovskite battery, such as a conductive substrate 3 provided with a hole transport layer 4, etc. Depending on the experiment or use condition, the substrate can have different structures, and therefore the specific structure of the substrate is not limited in the embodiment.

[0068] In this step, the perovskite light-absorbing layer 1 can be prepared by different processes according to the components of the perovskite light-absorbing layer 1. For example, when FA + In the embodiment, the perovskite light-absorbing layer 1 is prepared by a solution method.

[0069] Specifically, in order to simplify the preparation process of the perovskite thin film, the step can specifically include: arranging the perovskite light-absorbing layer 1 on the surface of the substrate based on an evaporation method. That is, the perovskite light-absorbing layer 1 and the subsequent perovskite passivation layer 2 in this step can be prepared by an evaporation method, and at this time, the preparation of the perovskite light-absorbing layer 1 and the subsequent perovskite passivation layer 2 can be carried out in the same evaporation equipment. Correspondingly, at this time, the components of the perovskite light-absorbing layer 1 need to meet the required components for preparation by the evaporation method.

[0070] Specifically, the step can specifically include: transferring the substrate into a vacuum chamber of a vacuum coating machine, placing a plurality of coating materials into corresponding evaporation boats, and placing the evaporation boats in the vacuum chamber; and evaporating the perovskite light-absorbing layer 1 on the surface of the substrate by the vacuum coating machine at a preset rate. In this step, the perovskite light-absorbing layer 1 can be arranged by a vacuum coating machine, and specifically, the substrate and the evaporation boats containing coating materials meeting the requirements of the vacuum coating machine can be placed in the vacuum chamber. Then, the perovskite light-absorbing layer 1 is arranged using a diaphragm coating machine.

[0071] Generally, after this step, the substrate provided with the perovskite light-absorbing layer 1 is annealed to complete the preparation of the perovskite light-absorbing layer 1.

[0072] S102: arranging the perovskite passivation layer on the surface of the perovskite light-absorbing layer based on an evaporation method.

[0073] In the embodiment, the material of the perovskite passivation layer is a full-inorganic material, and the band gap of the perovskite light-absorbing layer is smaller than that of the perovskite passivation layer. Specifically, in the embodiment, the perovskite passivation layer 2 can be A'B'X'3, A' is Cs + ; B' is a combination of one or more of Pb 2+ or Sn 2+ ; and X' is Cl - , Br - , or I -one or more of the above. The specific components of the perovskite passivation layer 2 are described in detail in the above-mentioned embodiments, and will not be described again here. Since the band gap of the perovskite film is adjustable, in this embodiment, the band gap of the prepared perovskite light-absorbing layer 1 is smaller than the band gap of the perovskite passivation layer 2.

[0074] In this step, the perovskite passivation layer 2 is specifically provided on the surface of the perovskite light-absorbing layer 1 based on an evaporation method, and the perovskite passivation layer 2 can also be prepared using the above-mentioned vacuum coating machine. Specifically, the step can include: evaporating the perovskite passivation layer 2 on the surface of the perovskite light-absorbing layer 1 at a predetermined rate by the vacuum coating machine. That is, after completing the annealing of the perovskite light-absorbing layer 1, the vacuum coating machine is used to evaporate the perovskite passivation layer 2 of the target component on the surface of the perovskite light-absorbing layer 1. After this step, the perovskite film is annealed to complete the preparation of the perovskite film.

[0075] The preparation method of the perovskite film provided by the embodiments of the present application can prepare the perovskite passivation layer 2 of the above-mentioned components on the surface of the perovskite light-absorbing layer 1 by an evaporation method, which has the advantages of environmental friendliness, no solvent, easy preparation, batch production, good film morphology, and no erosion of the underlying perovskite light-absorbing layer 1.

[0076] Embodiment 1

[0077] The preparation process of a perovskite film containing a pure inorganic perovskite passivation layer 2 will be provided below:

[0078] Firstly, the ITO (indium tin oxide) conductive glass is cleaned with a glass cleaning solution, deionized water, ethanol, and isopropanol, and then dried at 200 degrees. The ITO conductive glass is used as a device substrate. Then, the cleaned substrate is treated with ultraviolet light for 20 minutes. In a nitrogen glove box, 10 g of SnI2, 10 g of PbI2, 10 g of PbBr2, and 15 g of CsI are weighed and added to three evaporation boats, respectively. The evaporation boats are transferred to the cavity of the vacuum coating machine and positioned below the substrate. The vacuum degree is reduced to less than 10 -4 Pa, by adjusting the heating power of the four evaporation boats, the evaporation rate of the materials in the evaporation boats can be controlled, and then a stoichiometric perovskite film is obtained.

[0079] Secondly, the perovskite light-absorbing layer CsSn 0.5 Pb 0.5 I3: The evaporation rates of SnI2, PbI2, and CsI are controlled to be 1 nm / s, 1 nm / s, and 2 nm / s, respectively. The total thickness is 1200 nm. After evaporation, the substrate with the perovskite film is directly heated for annealing in the vacuum chamber, and the temperature is controlled at 150°C for 10 minutes.

[0080] Third step, preparation of perovskite passivation layer CsPb I2Br: after the first step of annealing is completed and completely cooled, continue to control the evaporation rate of PbBr2, Pb I2 and Cs I is 0.5 nm / s, 1 nm / s and 1.5 nm / s respectively. The total thickness is 40 nm. After the evaporation is completed, the substrate with perovskite film is directly heated in the vacuum chamber for annealing, the temperature is controlled at 150℃, and the time is 10 minutes.

[0081] The second step above obtains a perovskite light-absorbing layer 1 without a passivation layer, and the third step obtains a perovskite light-absorbing layer 1 / perovskite passivation layer 2 stack structure. As shown in Figure 3 The luminescence of the perovskite light-absorbing layer 1 without a passivation layer obtained in the second step is significantly weaker than that of the perovskite light-absorbing layer 1 / perovskite passivation layer 2 obtained in the third step, which indicates that the passivation layer can significantly passivate the interface defects, thereby reducing non-radiative recombination. In addition, the luminescence of the perovskite light-absorbing layer 1 has a weak blue shift after the passivation layer is added.

[0082] A perovskite battery will be provided below, and the structure of the perovskite battery can correspond to the structure of the perovskite film described above.

[0083] Please refer to Figure 4 , Figure 4 for a schematic structural diagram of a perovskite battery provided in an embodiment of the present application.

[0084] See Figure 4 , in an embodiment of the present application, the perovskite battery comprises: a conductive substrate 3; a hole transport layer 4 located on one side surface of the conductive substrate 3; a perovskite film located on the side surface of the hole transport layer 4 away from the conductive substrate 3; the perovskite film is the perovskite film described in any of the embodiments of the present application; the hole transport layer 4 is in contact with the perovskite light-absorbing layer 1; an electron transport layer 5 located on the side surface of the perovskite passivation layer 2 away from the conductive substrate 3; an electrode 6 located on the side surface of the electron transport layer 5 away from the conductive substrate 3.

[0085] The conductive substrate 3 is one side electrode of the perovskite battery, which can be an ITO substrate, or other single-layer or composite-layer substrate with conductive function, which is not specifically limited here.

[0086] The conductive substrate 3 with the hole transport layer 4 arranged thereon is used as the substrate in this step, and the perovskite film in the embodiments of the present application is arranged on the side surface of the hole transport layer 4 away from the conductive substrate 3, and specifically, the perovskite light-absorbing layer 1 in the perovskite film is in contact with the hole transport layer 4.

[0087] The electron transport layer 5 is located on the surface of the perovskite passivation layer 2 opposite to the conductive substrate 3, that is, the perovskite passivation layer 2 is located between the perovskite light-absorbing layer 1 and the electron transport layer 5. The electrode 6 is located on the surface of the electron transport layer 5 opposite to the conductive substrate 3, serving as the other electrode of the perovskite battery, thereby forming a complete perovskite battery structure.

[0088] The specific structure of the perovskite thin film has been described in detail in the above-mentioned embodiments, and will not be repeated here. The structures of the hole transport layer 4, the electron transport layer 5, etc. can refer to the prior art, and will not be repeated here.

[0089] The perovskite battery provided in the embodiments of the present application can be prepared by a vapor deposition method to prepare the perovskite passivation layer 2 of the above-mentioned components on the surface of the perovskite light-absorbing layer 1, which has the advantages of environmental friendliness, no solvent, easy preparation, batch production, good film morphology, and no erosion of the underlying perovskite light-absorbing layer 1.

[0090] The preparation method of the perovskite battery provided in the embodiments of the present application will be described below. The preparation method of the perovskite battery described below can be correspondingly referred to the perovskite battery described above.

[0091] Please refer to Figure 5 , Figure 5 The process flow chart of the preparation method of the perovskite battery provided in the embodiments of the present application.

[0092] Please refer to Figure 5 In the embodiments of the present application, the preparation method of the perovskite battery comprises:

[0093] S201: Preparing a hole transport layer on one side surface of a conductive substrate.

[0094] In this step, the hole transport layer 4 can be first provided on one side surface of the conductive substrate 3 by a magnetron sputtering method or the like. The specific material of the hole transport layer 4 is not specifically limited in the embodiments of the present application.

[0095] S202: Preparing a perovskite thin film on the surface of the hole transport layer.

[0096] In the embodiments of the present application, the preparation method of the perovskite thin film is the preparation method of the perovskite thin film described in any of the above-mentioned embodiments, which will not be repeated here; the substrate is the conductive substrate 3 provided with the hole transport layer 4, and the hole transport layer 4 is in contact with the perovskite light-absorbing layer 1. That is, in this embodiment, the conductive substrate 3 provided with the hole transport layer 4 is used as the substrate, the perovskite light-absorbing layer 1 is first provided on the surface of the hole transport layer 4, and then the perovskite passivation layer 2 is provided on the surface of the perovskite light-absorbing layer 1.

[0097] S203: Preparing an electron transport layer on the surface of the perovskite passivation layer.

[0098] In this step, the electron transport layer 5 can be prepared on the surface of the perovskite passivation layer 2 by evaporation or other methods. The specific material of the electron transport layer 5 is not limited in the embodiments of the present application.

[0099] S204: Preparing an electrode on the surface of the electron transport layer.

[0100] In this step, the electrode 6 can be prepared on the surface of the electron transport layer 5 by evaporation or other methods. The electrode 6 can be a copper electrode 6 or a silver electrode 6, etc. The specific material and preparation process of the electrode 6 are not limited in this embodiment.

[0101] The preparation method of the perovskite battery provided by the embodiments of the present application can prepare the perovskite passivation layer 2 with the above components on the surface of the perovskite light-absorbing layer 1 by the evaporation method, which has the advantages of environmental friendliness, no solvent, easy preparation, batch production, good film morphology, and no erosion of the underlying perovskite light-absorbing layer 1.

[0102] Embodiment 2

[0103] A preparation process of a perovskite battery containing a pure inorganic perovskite passivation layer 2 will be provided as follows:

[0104] First step, substrate cleaning: after the ITO conductive glass is cleaned by ultrasonic cleaning with glass cleaning solution, deionized water, ethanol, and isopropanol, it is dried at 200 degrees. The ITO conductive glass is used as the device substrate.

[0105] Second step, preparing a hole transport layer 4: a layer of nickel oxide is sputtered on the ITO composite layer as a hole transport layer 4 by a magnetron method, with a thickness of 15 nm.

[0106] Third step, preparing a perovskite light-absorbing layer CsSn 0.5 Pb 0.5 I3: the evaporation rates of Sn I2, Pb I2, and Cs I are controlled to be 1 nm / s, 1 nm / s, and 2 nm / s respectively. The total thickness is 1200 nm. After the evaporation is completed, the substrate with the perovskite film is directly heated in the vacuum chamber, the temperature is controlled to be 150℃, and the time is 10 minutes.

[0107] Fourth step, preparing a perovskite passivation layer CsPb I2Br: after the first step of annealing is completed and completely cooled, the evaporation rates of PbBr2, Pb I2, and Cs I are controlled to be 0.5, 1, and 1.5 nm / s respectively. The total thickness is 40 nm. After the evaporation is completed, the substrate with the perovskite film is directly heated in the vacuum chamber, the temperature is controlled to be 150℃, and the time is 10 minutes.

[0108] Fifth step, preparation of electron transport layer 5: 70 nm of fullerene C60, 7 nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline BCP (hole blocking material) as electron transport layer 5 were deposited by evaporation in sequence, with an evaporation rate of 1 nm / s.

[0109] Sixth step, preparation of metal electrode 6: 150 nm of copper electrode 6 was deposited by evaporation, with an evaporation rate of 2 nm / s.

[0110] The optimal performance of the pure inorganic full evaporation narrow-bandgap perovskite cell prepared by the above method is shown in Table 1 below, with a maximum efficiency of 22.8%. In addition, 122 devices of the above structure were prepared by the full evaporation method in this embodiment, with an average efficiency of 21.8±0.5%. The small standard error of device efficiency indicates that the perovskite cell prepared by the full evaporation method has relatively stable efficiency, further indicating the advantages of the full evaporation method in industrial production.

[0111] Table 1. Performance table of pure inorganic full evaporation narrow-bandgap perovskite cell

[0112]

[0113] Comparative Example 1

[0114] This comparative example provides a perovskite cell without a passivation layer, and the other structures and preparation processes are the same as those of Example 2, except that the perovskite passivation layer 2 is removed.

[0115] First step, substrate cleaning: the ITO conductive glass was cleaned with glass cleaning solution, deionized water, ethanol and isopropanol, and then dried at 200 degrees. The ITO conductive glass was used as the device substrate.

[0116] Second step, preparation of hole transport layer 4: a layer of nickel oxide hole transport layer 4 with a thickness of 15 nm was sputtered on the ITO composite layer using a magnetron.

[0117] Third step, preparation of perovskite light-absorbing layer CsSn 0.5 Pb 0.5 I3: the evaporation rates of Sn I2, Pb I2 and Cs I were controlled to be 1 nm / s, 1 nm / s and 2 nm / s respectively. The total thickness was 1200 nm. After evaporation, the substrate with the perovskite film was directly heated in the vacuum chamber, with a temperature control of 150°C for 10 minutes.

[0118] Fourth step, preparation of electron transport layer 5: 70 nm of fullerene C60, 7 nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline BCP were deposited by evaporation in sequence, with an evaporation rate of 1 nm / s.

[0119] Fifth step, preparation of metal electrode 6: 150nm copper electrode 6 was deposited by evaporation, with an evaporation rate of 2nm / s.

[0120] Comparative Example 2

[0121] This comparative example provides a perovskite battery containing an alkali metal halide passivation layer, which is different from Example 2 in that the perovskite passivation layer 2 is replaced by an alkali metal passivation layer of the same thickness. The pure inorganic passivation layer used in Example 2 is CsPbI2Br, and in order to better compare, the alkali metal halide passivation layer uses CsI.

[0122] First step, substrate cleaning: after the ITO conductive glass was cleaned with glass cleaning solution, deionized water, ethanol, isopropanol and ultrasonic cleaning, it was dried at 200 degrees, and the ITO conductive glass was used as the device substrate.

[0123] Second step, preparation of hole transport layer 4: a layer of nickel oxide hole transport layer 4 with a thickness of 15nm was sputtered on the ITO composite layer by magnetron.

[0124] Third step, preparation of perovskite light-absorbing layer CsSn 0.5 Pb 0.5 I3: control the evaporation rate of SnI2, PbI2 and CsI to be 1, 1 and 2nm / s respectively. The total thickness is 1200nm. After evaporation, the substrate with perovskite film was directly heated in the vacuum chamber, with a temperature control of 150℃ for 10 minutes.

[0125] Fourth step, preparation of alkali metal halide CsI passivation layer: after the first step of annealing was completed and completely cooled, the evaporation rate of CsI was controlled to be 1.5nm / s. The total thickness is 5nm. After evaporation, the substrate with perovskite film was directly heated in the vacuum chamber, with a temperature control of 150℃ for 10 minutes.

[0126] Fifth step, preparation of electron transport layer 5: 70nm of fullerene C60 and 7nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline BCP were sequentially deposited by evaporation, with an evaporation rate of 1nm / s.

[0127] Sixth step, preparation of metal electrode 6: 150nm copper electrode 6 was deposited by evaporation, with an evaporation rate of 2nm / s.

[0128] It should be noted that since the alkali metal halide CsI passivation layer has poor conductivity, it cannot be evaporated to the same thickness as the perovskite passivation layer 2 in Example 2.

[0129] Comparative Example 1 is a perovskite cell without a passivation layer, Example 2 is a perovskite cell with a pure inorganic perovskite passivation layer 2, and Comparative Example 2 is a perovskite cell with an alkali halide passivation layer. The performance parameters are shown in Table 2 below:

[0130] Table 2. Comparison table of cell performance parameters

[0131]

[0132] The perovskite cell in Comparative Example 1 does not deposit any passivation layer on top of the perovskite light-absorbing layer 1, and there are a large number of defects at the interface, resulting in low open-circuit voltage, short-circuit current, and fill factor, ultimately leading to low efficiency. The perovskite cell in Comparative Example 2 deposits 5 nm of CsI alkali halide, which significantly improves the efficiency compared to Comparative Example 1. The perovskite cell in Example 2 deposits a 40 nm CsPbI2Br pure inorganic perovskite passivation layer 2, which has the highest efficiency, mainly due to the fact that the pure inorganic perovskite passivation layer 2 has the same crystal type as the perovskite light-absorbing layer 1, with a high lattice matching degree, the best interface defect passivation effect, and the perovskite passivation layer 2 itself also has similar conductivity to the perovskite light-absorbing layer 1.

[0133] Example 3

[0134] A preparation process for a perovskite cell with a pure inorganic perovskite passivation layer 2 will be provided below, in which the composition of the perovskite light-absorbing layer is different from that of Example 2, and is prepared by a solution method. Solution method and evaporation method are common ways to prepare perovskite light-absorbing layer:

[0135] First step, substrate cleaning: after ultrasonic cleaning the ITO conductive glass with glass cleaning solution, deionized water, ethanol, isopropanol, and drying at 200 degrees, the ITO conductive glass is used as the device substrate.

[0136] Second step, preparation of hole transport layer 4: a layer of nickel oxide is sputtered on the ITO composite layer as a hole transport layer 4 using a magnetron method, with a thickness of 15 nm.

[0137] Third step, preparation of perovskite light-absorbing layer, 1.5 mmol of PbI2, 1.4 mmol of FAI (formamidinium iodide), and 0.7 mmol of MACI (methylammonium chloride) are dissolved in 0.8 mL of DMF (dimethylformamide) and 0.2 mL of DMSO (dimethyl sulfoxide). Separately, 1 mmol of MABr (methylammonium bromide) and 1 mmol of PbBr2 are dissolved in 0.8 mL of DMF and 0.2 mL of DMSO. Separately, 1.5 mmol of CsI is dissolved in 1 mL of DMSO. The three solutions are mixed in a volume ratio of 72:28:5. During spin coating at a speed of 3500 rpm for 30 s, chlorobenzene is quickly added as an anti-solvent at 20 s. The spin-coated substrate is placed on a heating stage for annealing treatment; the annealing temperature is 100°C, and the annealing time is 30 min.

[0138] Fourth step, preparation of perovskite passivation layer CsPbI2Br: after the first step of annealing is completed and completely cooled, the evaporation rates of PbBr2, PbI2, and CsI are controlled to be 0.5 nm / s, 1 nm / s, and 1.5 nm / s, respectively. The total thickness is 40 nm. After evaporation is completed, the substrate with the perovskite film is directly heated in the vacuum chamber, with the temperature controlled to be 150°C for 10 minutes.

[0139] Fifth step, preparation of electron transport layer 5: 70 nm of fullerene C60 and 7 nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline BCP (hole blocking material) are sequentially deposited as the electron transport layer 5, with an evaporation rate of 1 nm / s.

[0140] Sixth step, preparation of metal electrode 6: a 150 nm copper electrode 6 is deposited by evaporation, with an evaporation rate of 2 nm / s.

[0141] Comparative Example 3

[0142] First step, substrate cleaning: the ITO conductive glass is ultrasonically cleaned with glass cleaning solution, deionized water, ethanol, and isopropanol, and then dried at 200°C. The ITO conductive glass is used as the device substrate.

[0143] Second step, preparation of hole transport layer 4: a layer of nickel oxide is sputtered on the ITO composite layer as the hole transport layer 4, with a thickness of 15 nm, using a magnetron.

[0144] Third step, preparation of perovskite light-absorbing layer, 1.5 mmol of PbI2, 1.4 mmol of FAI, 0.7 mmol of MACI were dissolved in 0.8 mL of DMF and 0.2 mL of DMSO. 1 mmol of MABr and 1 mmol of PbBr2 were dissolved in 0.8 mL of DMF and 0.2 mL of DMSO. 1.5 mmol of CsI was dissolved in 1 mL of DMSO. The three solutions were mixed in a volume ratio of 72:28:5. The spin coating speed was 3500 rpm, and the spin coating time was 30 s. Chlorobenzene was quickly added as an anti-solvent at 20 s of spin coating. The spin-coated substrate was placed on a heating stage for annealing treatment; the annealing temperature was 100°C, and the annealing time was 30 min.

[0145] Fourth step, preparation of electron transport layer 5: 70 nm of fullerene C60 and 7 nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline BCP (hole blocking material) were sequentially deposited as the electron transport layer 5 at a deposition rate of 1 nm / s.

[0146] Fifth step, preparation of metal electrode 6: 150 nm of copper electrode 6 was deposited at a deposition rate of 2 nm / s.

[0147] Comparative Example 3 is a perovskite cell without a passivation layer, and Example 3 is a perovskite cell with a pure inorganic perovskite passivation layer 2. The two cells are identical in structure except for the passivation layer. The performance parameters are shown in Table 3 below:

[0148]

[0149] In another perovskite cell system, the strategy provided by the present application also improves the efficiency of the perovskite cell by 2.7%.

[0150] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts of each embodiment can be referred to each other.

[0151] Those skilled in the art will further appreciate that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. In order to clearly illustrate the interchangeability of hardware and software, the components and steps of the examples have been described in the above description in general terms. Whether the functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0152] The steps of a method or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in RAM, flash memory, ROM, electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. The term "computer-readable storage medium" includes, but is not limited to, non-transitory, tangible, and non-transitory, tangible media that store data for

[0153] Finally, it should be noted that, in the present document, relational terms such as first and second, and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Additionally, unless otherwise stated, the term "about" preceding a value or description is understood in accordance with the phrase "within an acceptable manufacturing tolerance of" that value or description.

[0154] The above provides a perovskite thin film, a perovskite battery and a preparation method thereof. The principles and implementation manners of the present application are described by using specific examples. The above examples are only used to help understand the method and core idea of the present application. It should be pointed out that, for those skilled in the art, without departing from the principles of the present application, some improvements and modifications can be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A perovskite thin film, characterized by, The perovskite light-absorbing layer and the perovskite passivation layer on one side surface of the perovskite light-absorbing layer; the material of the perovskite passivation layer is a full inorganic material, and the band gap of the perovskite light-absorbing layer is smaller than that of the perovskite passivation layer.

2. The perovskite thin film according to claim 1, characterized by The perovskite light-absorbing layer is ABX3, A is one or more of MA + , FA + , Cs + in combination; B is one or more of Pb 2+ or Sn 2+ in combination; X is one or more of Cl - , Br - , I - in combination; The perovskite passivation layer is A'B'X'3, A' is Cs + ; B' is Pb 2+ or Sn 2+ in combination of one or more; X' is Cl - , Br - , I - in combination of one or more.

3. The perovskite thin film according to claim 2, characterized by B' of the perovskite passivation layer is Pb 2+ ; X' is a combination of one or several of Br - , I - .

4. The perovskite thin film according to claim 2, characterized by The thickness of the perovskite light-absorbing layer is 400 nm to 2500 nm.

5. The perovskite thin film according to claim 2, characterized by The thickness of the perovskite passivation layer is 10 nm to 40 nm.

6. A method for preparing a perovskite thin film, characterized by, The method comprises the following steps: Preparation of the perovskite light-absorbing layer on the surface of the substrate; Preparation of the perovskite passivation layer on the surface of the perovskite light-absorbing layer by the evaporation method; The material of the perovskite passivation layer is a full inorganic material, and the band gap of the perovskite light-absorbing layer is smaller than that of the perovskite passivation layer.

7. The method of claim 6, wherein, The perovskite light-absorbing layer is ABX3, A is one or more of MA + , FA + , Cs + in combination; B is one or more of Pb 2+ or Sn 2+ in combination; X is one or more of Cl - , Br - , I - in combination; The perovskite passivation layer is A'B'X'3, A' is Cs + ; B' is Pb 2+ or Sn 2+ in combination of one or more; X' is Cl - , Br - , I - in combination of one or more.

8. The method of claim 6, wherein, Preparation of the perovskite light-absorbing layer on the surface of the substrate comprises the following steps: Preparation of the perovskite light-absorbing layer on the surface of the substrate by the evaporation method.

9. The method of claim 8, wherein, Preparation of the perovskite light-absorbing layer on the surface of the substrate by the evaporation method comprises the following steps: Transfer of the substrate into the vacuum chamber of the vacuum coating machine, placement of multiple coating materials into corresponding evaporation boats, and placement of the evaporation boats in the vacuum chamber; Evaporation of the perovskite light-absorbing layer on the surface of the substrate by the vacuum coating machine at a preset rate; Preparation of the perovskite passivation layer on the surface of the perovskite light-absorbing layer by the evaporation method comprises the following steps: Evaporation of the perovskite passivation layer on the surface of the perovskite light-absorbing layer by the vacuum coating machine at a preset rate.

10. The method of claim 9, wherein, Before evaporation of the perovskite passivation layer on the surface of the perovskite light-absorbing layer at a preset rate, the method further comprises the following steps: Annealing of the substrate provided with the perovskite light-absorbing layer; After evaporation of the perovskite passivation layer on the surface of the perovskite light-absorbing layer at a preset rate, the method further comprises the following steps: Annealing of the perovskite thin film.

11. A perovskite cell, characterized in that, The method comprises the following steps: Preparation of the conductive substrate; Preparation of the hole transport layer on one side surface of the conductive substrate; Preparation of the perovskite thin film on the side surface of the hole transport layer away from the conductive substrate; The perovskite thin film is the perovskite thin film as claimed in any one of claims 1 to 5; the hole transport layer is in contact with the perovskite light-absorbing layer; Preparation of the electron transport layer on the side surface of the perovskite passivation layer away from the conductive substrate; Preparation of the electrode on the side surface of the electron transport layer away from the conductive substrate.

12. A method of producing a perovskite cell, characterized by, The method comprises the following steps: Preparation of the hole transport layer on one side surface of the conductive substrate; Preparation of the perovskite thin film on the surface of the hole transport layer; the preparation method of the perovskite thin film is the preparation method of the perovskite thin film as claimed in any one of claims 6 to 10; the substrate is the conductive substrate provided with the hole transport layer, and the hole transport layer is in contact with the perovskite light-absorbing layer; Preparation of the electron transport layer on the surface of the perovskite passivation layer; Preparation of the electrode on the surface of the electron transport layer.

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