Perovskite solar cell, preparation method thereof and electrical device

Abstract

This application relates to the technical field of solar cells, and particularly to a preparation method of a perovskite solar cell, comprising the following steps: preparing a first electrode on a base layer, and preparing a perovskite wet film on the first electrode using a perovskite solution; performing a crystallization treatment on the perovskite wet film to obtain a perovskite thin film with a residual part of the solvent; performing a microwave annealing treatment on the perovskite thin film to prepare a perovskite active layer; preparing a second electrode on the perovskite active layer; wherein, the chemical formula of the perovskite is denoted as ABX3, wherein, A includes formamidinium cations and / or Cs + , B includes Pb 2+ , Sn 2+ and other divalent metal cations, X includes Br ‑ and / or I ‑ ; the area of the perovskite thin film ≥ 0.003 m 2 . This preparation method can effectively avoid the problems of uneven annealing and solvent residue after annealing that may be brought about by the preparation method using small-area perovskite.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and particularly to a perovskite solar cell, a preparation method thereof, and an electrical device using the same. Background Art

[0002] Due to the shortage of traditional energy sources and the new demand for green energy in modern society, solar cells that can convert light energy into electrical energy through the photovoltaic effect or the photochemical effect have developed rapidly. Currently, solar cells have developed to the third generation, namely perovskite solar cells. Perovskite solar cells have the advantages of high photoelectric conversion efficiency, low power generation cost, etc., and have the potential for integration with buildings. It is expected to become a substitute for the curtain wall decoration of high-rise buildings, thereby achieving lighting and power generation simultaneously.

[0003] In perovskite solar cells, the crystallization of the perovskite thin film has a direct impact on the quality of the formed perovskite active layer, and thus affects the battery performance. The traditional preparation method of the perovskite active layer is mainly developed for small-area (for example, 1.5 cm 2 ×1.5 cm 2 ) perovskite thin films. It does not consider problems such as uneven heat absorption and solvent residue during annealing of large-area perovskite thin films, and thus cannot cope with the preparation of large-area perovskite active layers, which greatly hinders the development of the application scenario of the integration of perovskite solar cells with buildings that requires large-area use. Summary of the Invention

[0004] Based on this, it is necessary to provide a preparation method for a perovskite solar cell applicable to large areas, the perovskite solar cell prepared by this preparation method, and an electrical device including this battery. This preparation method can avoid problems such as uneven heat absorption and solvent residue during annealing of large-area perovskite active layers, and contribute to the development of the integration of perovskite solar cells with buildings.

[0005] In the first aspect of the present application, a preparation method for a perovskite solar cell is provided, which includes the following steps:

[0006] Provide a base layer with a first electrode, and prepare a perovskite wet film on the first electrode using a perovskite solution;

[0007] Perform crystallization treatment on the perovskite wet film to obtain a perovskite thin film with some solvent remaining;

[0008] Perform microwave annealing treatment on the perovskite thin film to prepare a perovskite active layer;

[0009] Prepare a second electrode on the perovskite active layer;

[0010] Among them, the chemical formula of the perovskite is denoted as ABX3, where A includes formamidinium cations and / or Cs + , B includes Pb 2 + , Sn 2+ , Ge 2+ , Co 2+ , Fe 2+ , Mn 2+ , Cu 2+ and Ni 2+ one or more of them, and X includes Br- and / or I-;

[0011] The area of the perovskite thin film ≥ 0.003m 2 .

[0012] By defining the specific composition of the perovskite and controlling that there is still a certain amount of solvent in the perovskite thin film obtained after wet film crystallization, microwave annealing treatment can be carried out on a large-area perovskite thin film with an area ≥ 0.003m 2 . This can effectively avoid the problems of uneven annealing of the perovskite thin film and solvent residue after annealing that may be brought about by the preparation method of small-area perovskite solar cells in the traditional technology. The obtained perovskite active layer has large grain particles and high quality, and the prepared large-area perovskite solar cell has a higher photoelectric conversion efficiency.

[0013] In some embodiments, A includes formamidinium cations and Cs + , and the proportion of formamidinium cations in A is 70% - 95%. By compounding formamidinium cations and cesium ions in a certain proportion, the two properties of the band gap and thermal stability of the perovskite can be better balanced, so that the large-area perovskite of the present application has relatively high stability, thus being suitable for the microwave annealing process and avoiding the decomposition of the perovskite and the appearance of defects in the thin film during microwave annealing; at the same time, the band gap can be controlled not to be too large to avoid adverse effects on the performance of the battery.

[0014] In some embodiments, the proportion of Br- in X is 0 - 50%.

[0015] In some embodiments, the proportion of Br- in X is 0 - 20%. Introducing a certain amount of bromide ions can enhance the stability of the perovskite and make the perovskite better match the overall heterojunction band gap, which can slow down the degradation degree of the perovskite battery exposed to a high-humidity environment.

[0016] In some embodiments, the microwave frequency of the microwave annealing treatment is 890MHz - 940MHz or 2400MHz - 2500MHz.

[0017] In some embodiments, the microwave power of the microwave annealing treatment is 50W - 5000W.

[0018] In some embodiments, the time of the microwave annealing treatment is 0.5 min to 20 min.

[0019] In some embodiments, the temperature of the microwave annealing treatment is 80 °C to 200 °C.

[0020] During the microwave annealing treatment, parameters such as the microwave frequency, power, annealing temperature, and annealing time will directly affect the quality of the final perovskite active layer, and thus affect the battery performance. When performing the microwave annealing treatment, the size and chemical composition of the perovskite thin film should be fully considered to set more appropriate microwave annealing treatment parameters.

[0021] In some embodiments, when the thickness ratio of the obtained perovskite thin film to the initial perovskite wet film is 1:(4 - 10), the crystallization treatment is stopped. Controlling the thickness ratio of the perovskite thin film and the wet film within a certain range is actually to control the appropriate amount of solvent remaining in the perovskite thin film after the crystallization treatment. Since during the microwave annealing treatment, the heat conduction of the perovskite thin film depends on the residual solvent in the thin film absorbing microwave energy, becoming polarized, and generating a thermal effect outward to achieve, therefore, an appropriate amount of solvent residue can make the heat conduction proceed better, which can not only make the annealing proceed thoroughly, but also avoid the residual solvent in the perovskite active layer after the annealing ends, affecting the use.

[0022] In some embodiments, the perovskite wet film is formed by coating or inkjet printing. By forming the perovskite wet film through coating or inkjet printing in this application, it is possible to avoid the additional introduction of a poor solvent for perovskite when using the spin coating method in the traditional technology, and further reduce the solvent residue in the perovskite active layer.

[0023] In some embodiments, in the perovskite solution, the molar concentration of ABX3 is 0.7 mol / L to 1.3 mol / L.

[0024] In some embodiments, the thickness of the perovskite wet film is 2.8 μm to 3.4 μm.

[0025] An appropriate molar concentration of ABX3 can make the thickness of the formed perovskite wet film moderate, and it is easier to process the perovskite active layer with the thickness required in the industry.

[0026] In some embodiments, the dipole moment of some residual solvents in the perovskite film is 0.1 to 0.9. Under the action of microwaves, an object will have charge imbalance for small molecules that make up the object due to the alternating electric field, and then absorb these electromagnetic waves to polarize some molecules with dipole moments, resulting in accelerating the irregular Brownian motion of small molecules and accelerating collisions. Due to these collision effects, heat is generated in these small molecules, that is, for an object, the heating of the object starts from small molecules in the microwave, that is, heat is transferred from the inside of the object to the periphery of small molecules. Therefore, for an object to have a thermal effect in the microwave, it must have the ability of dipole polarization, that is, it must have a dipole moment. A suitable dipole moment can make the evaporation rate of the solvent moderate during the annealing of the perovskite film, so that cavities do not appear between grains due to too fast evaporation rate, making the active layer relatively loose; nor will it absorb energy too slowly due to too small polarity, resulting in too slow evaporation rate and residual solvent in the inner layer, causing degradation of the active layer after long-term use and affecting the battery performance.

[0027] In some embodiments, the solvent in the perovskite solution includes one or more of N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), and dimethyl sulfoxide (DMSO). A suitable solvent type not only has a suitable dipole moment, but also takes into account the solubility of perovskite and will not cause the decomposition of perovskite.

[0028] In some embodiments, the method for crystallizing the perovskite wet film includes vacuum drying treatment and / or air knife blowing treatment.

[0029] In some embodiments, the vacuum degree of the vacuum drying treatment is 1.0 Pa to 10 3 Pa.

[0030] In some embodiments, the blowing gas pressure of the air knife blowing treatment is 0 to 2.0 MPa.

[0031] Appropriate vacuum drying treatment or air knife blowing treatment parameters can make the evaporation rate of the solvent in the perovskite wet film moderate, which helps to form a perovskite film with a suitable solvent residue amount during the initial crystallization.

[0032] In some embodiments, the method for preparing the perovskite solar cell further includes the following steps: forming a first transport layer on the first electrode, and forming the perovskite wet film on the first transport layer.

[0033] In some embodiments, the method for preparing the perovskite solar cell further includes the following steps: forming a second transport layer on the perovskite active layer, and forming the second electrode on the second transport layer.

[0034] In a second aspect of the present application, a perovskite solar cell is provided, which is prepared by the preparation method described in one or more of the foregoing embodiments.

[0035] In some embodiments, the perovskite solar cell includes a substrate layer, a first electrode, a first transport layer, the perovskite active layer, a second transport layer, and a second electrode that are stacked in sequence.

[0036] In some embodiments, the perovskite solar cell has a reverse structure, the first transport layer is a hole transport layer, and the second transport layer is a charge transport layer.

[0037] In some embodiments, the perovskite solar cell has a normal structure, the first transport layer is a charge transport layer, and the second transport layer is a hole transport layer.

[0038] In some embodiments, the thickness of the first transport layer of the perovskite solar cell with a normal structure is 20 nm to 50 nm. In the perovskite solar cell with a normal structure, since the first transport layer, that is, the charge transport layer, needs to be subjected to microwave annealing treatment together with the perovskite active layer, and there are components in the charge transport layer that are unstable to microwaves, it is necessary to control the thickness of the charge transport layer within a suitable range to avoid the loss of the charge transport layer caused by microwave annealing, and at the same time not cause too much negative impact on the overall thickness of the battery.

[0039] In a third aspect of the present application, an electrical device is further provided, including the perovskite solar cell described in one or more of the foregoing embodiments. Description of the Drawings

[0040] Figure 1 Scanning electron microscope image of the perovskite active layer prepared in Example 1;

[0041] Figure 2 Scanning electron microscope image of the perovskite active layer prepared in Comparative Example 1;

[0042] Figure 3 Scanning electron microscope image of the perovskite active layer prepared in Comparative Example 4. Detailed Embodiments

[0043] To facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0044] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically defined. In the description of the present application, the meaning of "several" is at least one, such as one, two, etc., unless otherwise specifically defined.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application pertains. The terms used in the description of this application herein are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0046] In this application, among the technical features described in an open-ended manner, it includes a closed technical solution composed of the listed features, and also includes an open technical solution containing the listed features.

[0047] In this application, regarding numerical ranges, unless otherwise specified, the above numerical ranges are considered continuous and include the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when the range refers to integers, it includes each integer between the minimum and maximum values of the range. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0048] In this application, for the percentage content involved, unless otherwise specified, for solid-liquid mixing and solid-solid mixing, it refers to the mass percentage, and for liquid-liquid mixing, it refers to the volume percentage.

[0049] In this application, for the percentage concentration involved, unless otherwise specified, it refers to the final concentration. The final concentration refers to the proportion of the added component in the system after adding this component.

[0050] In this application, for the temperature parameter, unless otherwise specifically limited, it allows both constant temperature treatment and treatment within a certain temperature range. The constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument.

[0051] In the preparation process of perovskite solar cells, the preparation of the perovskite active layer occupies a very important position because the quality of the perovskite active layer will directly affect the electrical performance of the solar cell. The perovskite active layer is usually obtained by annealing the perovskite thin film that is initially crystallized after most of the solvent in the perovskite wet film has evaporated. The current annealing processes are mainly divided into two categories. One is direct contact annealing on a hot plate, and the other is microwave annealing. Direct contact annealing on a hot plate mainly achieves heat conduction through direct contact of objects. Therefore, for large-area perovskite thin films, problems such as uneven annealing, local overheating, or local non-heating are likely to occur, damaging the quality of the perovskite active layer. In addition, direct contact annealing on a hot plate often requires a long heating time, and too long an annealing time is likely to cause decomposition of the organic components of the perovskite, which has a greater negative impact on production efficiency and the yield rate. Microwave annealing is currently less used, and the only existing research is on processes developed for small-area components (0.002 m 2 Below, for example, 1.5 cm * 1.5 cm). Since the requirements for heating uniformity and the like faced by large-area annealing do not need to be considered, its process parameters and perovskite composition have no practical reference value for the annealing process of large-area perovskite thin films.

[0052] Based on the above background, in the first aspect of the present application, a method for preparing a perovskite solar cell is provided, which includes the following steps:

[0053] Provide a substrate layer with a first electrode, and prepare a perovskite wet film on the first electrode using a perovskite solution;

[0054] Perform crystallization treatment on the perovskite wet film to obtain a perovskite thin film with some solvent remaining;

[0055] Perform microwave annealing treatment on the perovskite thin film to prepare a perovskite active layer;

[0056] Prepare a second electrode on the perovskite active layer;

[0057] Among them, the chemical formula of the perovskite is denoted as ABX3, where A includes formamidinium cations and / or Cs + , B includes Pb 2+ , Sn 2 + , Ge 2+ , Co 2+ , Fe 2+ , Mn 2+ , Cu 2+ and Ni 2+ one or more of them, and X includes Br- and / or I - ;

[0058] The area of the perovskite thin film ≥ 0.003 m 2 .

[0059] It can be understood that in the present application, preparing or forming the target layer B on a certain layer A includes directly preparing or forming the target layer B on this layer A, and also includes preparing or forming layer B on other layers C, D... above this layer A. For example, "preparing a perovskite wet film on the first electrode using a perovskite solution" means that a perovskite wet film can be directly prepared and formed on the surface of the first electrode, or other film layers such as a charge transport layer or a hole transport layer can be first prepared on the surface of the first electrode, and then a perovskite wet film can be prepared and formed on the surface of the charge transport layer or the hole transport layer.

[0060] Optionally, the area of the perovskite thin film can be, for example, 0.01 m 2 ~5 m 2 , or it can also be 0.05 m 2 , 0.09 m 2 , 0.1 m 2 , 0.5 m 2 , 1 m 2 , 2 m 2 or 5 m 2 .

[0061] By defining the specific composition of the perovskite and controlling that there is still a certain amount of solvent in the perovskite thin film obtained after the crystallization of the wet film, annealing treatment can be carried out on a large-area perovskite thin film with an area ≥ 0.003 m 2 by microwave, which can effectively avoid the problems of uneven annealing of the perovskite thin film and solvent residue after annealing that may be brought about by the preparation method of small-area perovskite solar cells in the traditional technology. The obtained perovskite active layer has large grain particles and high quality, and the prepared large-area perovskite solar cell has a higher photoelectric conversion efficiency.

[0062] In some embodiments, the proportion of the number of formamidinium cations in A can be, for example, 5% to 95%, or it can also be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or 90%.

[0063] In some embodiments, A includes formamidinium cations and Cs +, and the proportion of formamidinium cations in A is 70% to 95%. Optionally, the proportion of formamidinium cations in A is 74%, 78%, 82%, 86%, 90% or 94%. By compounding formamidinium cations and cesium ions in a certain proportion, the two properties of the bandgap and thermal stability of the perovskite can be better balanced, so that the large-area perovskite of the present application can have relatively high stability, thus being suitable for the microwave annealing process and avoiding the decomposition of the perovskite and the appearance of defects in the film during microwave annealing. At the same time, the bandgap can be controlled not to be too large to avoid adverse effects on the performance of the battery.

[0064] In some embodiments, the proportion of Br - in X is 0 to 50%.

[0065] In some embodiments, the proportion of Br - in X is 0 to 20%. The proportion of Br - in X can also be, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40% or 45%. Introducing a certain amount of bromide ions can enhance the stability of the perovskite and make the perovskite more matched with the overall heterojunction bandgap, which can slow down the degradation degree of the perovskite battery exposed to a high-humidity environment.

[0066] It can be understood that in the present application, the proportion of each ion can be reflected in the following form: for example, when A contains both formamidinium cations (FA + ) and Cs + , and the proportion of formamidinium cations in A is 95%, the proportion of Cs + is 5%, B is selected as Pb 2 + , X contains both Br - and I - , and the proportion of Br - in X is 20%, then ABX3 is denoted as FA 0.95 Cs 0.05 Pb(Br 0.2 I 0.8 )3.

[0067] In some embodiments, the microwave frequency of the microwave annealing treatment is 890 MHz to 940 MHz or 2400 MHz to 2500 MHz. Optionally, the microwave frequency of the microwave annealing treatment is 915 MHz or 2450 MHz.

[0068] In some embodiments, the microwave power of the microwave annealing treatment is 50 W to 5000 W. The microwave power can also be, for example, 100 W, 200 W, 450 W, 500 W, 650 W, 800 W, 1000 W, 2000 W, 3000 W or 4000 W.

[0069] In some embodiments, the time of the microwave annealing treatment is 0.5 min to 20 min. For example, the time of the microwave annealing treatment can also be 1 min, 3 min, 5 min, 7 min, 9 min, 10 min, 11 min, 13 min, 15 min, 17 min, or 19 min.

[0070] In some embodiments, the temperature of the microwave annealing treatment is 80°C to 200°C. For example, the temperature of the microwave annealing treatment can also be 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, or 195°C.

[0071] During the microwave annealing treatment, parameters such as the microwave frequency, power, annealing temperature, and annealing time will directly affect the quality of the final perovskite active layer, and thus affect the battery performance. When performing the microwave annealing treatment, the size and chemical composition of the perovskite thin film should be fully considered to set more appropriate microwave annealing treatment parameters.

[0072] In some embodiments, when the thickness ratio of the obtained perovskite thin film to the initial perovskite wet film is 1:(4 - 10), the crystallization treatment is stopped; optionally, the thickness ratio of the perovskite thin film to the perovskite wet film can also be, for example, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, or 1:9.5. Controlling the thickness ratio of the perovskite thin film and the wet film within a certain range is actually to control the appropriate amount of solvent remaining in the perovskite thin film after the crystallization treatment. Since during the microwave annealing treatment, the heat conduction of the perovskite thin film depends on the residual solvent in the thin film absorbing microwave energy, polarizing, and generating a thermal effect outward to achieve, an appropriate amount of solvent residue can make the heat conduction proceed better, which can not only make the annealing proceed thoroughly but also avoid the residual solvent in the perovskite active layer after the annealing, affecting the use.

[0073] In some embodiments, the perovskite wet film is formed by coating or inkjet printing. By forming the perovskite wet film through coating or inkjet printing in this application, it is possible to avoid the additional introduction of poor solvents for the perovskite when using the spin coating method in the traditional technology, and further reduce the solvent residue in the perovskite active layer.

[0074] In some embodiments, in the perovskite solution, the molar concentration of ABX3 is 0.7 mol / L to 1.3 mol / L. Optionally, the molar concentration of ABX3 can also be, for example, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L, or 1.2 mol / L.

[0075] In some embodiments, the thickness of the perovskite wet film is 2.8 μm to 3.4 μm. The thickness of the perovskite wet film can also be, for example, 2.9 μm, 3 μm, 3.1 μm, 3.2 μm, or 3.3 μm.

[0076] A suitable molar concentration of ABX3 can result in a perovskite wet film with a moderate thickness, making it easier to process a perovskite active layer with the required thickness in the industry.

[0077] In some embodiments, the dipole moment of some of the solvents remaining in the perovskite film is 0.1 to 0.9. Optionally, the dipole moment of the solvent can also be, for example, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or 0.8. Under microwave action, an object will have an uneven charge distribution on the small molecules that make up the object due to the alternating electric field, and then absorb these electromagnetic waves to polarize some molecules with dipole moments, resulting in an accelerated and irregular Brownian motion of the small molecules, causing heat generation due to collisions between the small molecules. That is, for an object, the heating of the object starts from the small molecules in the microwave, that is, heat is transferred from the inside of the object to the periphery of the small molecules. Therefore, for an object to have a thermal effect in the microwave, it must have the ability of dipole polarization, that is, it must have a dipole moment. A suitable dipole moment can make the evaporation rate of the solvent moderate during the annealing process of the perovskite film, so that cavities do not appear between the grains due to too fast evaporation rate, making the active layer loose; nor will the evaporation rate be too slow due to too small polarity and too slow energy absorption, resulting in residual solvent in the inner layer, causing degradation of the active layer after long-term use and affecting the battery performance.

[0078] In some embodiments, the solvent in the perovskite solution includes one or more of N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), and dimethyl sulfoxide (DMSO). A suitable solvent type not only has a suitable dipole moment, but also takes into account the solubility of the perovskite and will not cause decomposition of the perovskite.

[0079] In some embodiments, the methods for crystallizing the perovskite wet film include vacuum drying treatment and / or air knife blowing treatment.

[0080] In some embodiments, the vacuum degree of the vacuum drying treatment is 1.0 Pa to 10 3 Pa.

[0081] In some embodiments, the purge gas pressure for the air knife purge treatment is 0 to 2.0 MPa.

[0082] In some embodiments, the gas used for the air knife purge treatment is a non-reactive gas, which refers to a gas that does not chemically react with the perovskite. For example, it may include nitrogen, argon, etc.

[0083] Appropriate vacuum drying treatment or air knife purge treatment parameters can make the solvent evaporation rate in the perovskite wet film moderate, which helps the initial crystallization to form a perovskite film with an appropriate solvent residue amount.

[0084] In some embodiments, the method for preparing a perovskite solar cell further includes the following steps: forming a first transport layer on the first electrode, and forming a perovskite wet film on the first transport layer.

[0085] In some embodiments, the method for preparing a perovskite solar cell further includes the following steps: forming a second transport layer on the perovskite active layer, and forming a second electrode on the second transport layer.

[0086] In a second aspect of the present application, a perovskite solar cell is provided, which is prepared by the preparation method of one or more of the foregoing embodiments.

[0087] In some embodiments, the perovskite solar cell includes a substrate layer, a first electrode, a first transport layer, a perovskite active layer, a second transport layer, and a second electrode that are sequentially stacked.

[0088] In some embodiments, the perovskite solar cell has a reverse structure, the first transport layer is a hole transport layer, and the second transport layer is an electron transport layer.

[0089] In some embodiments, the perovskite solar cell has a normal structure, the first transport layer is an electron transport layer, and the second transport layer is a hole transport layer.

[0090] In some embodiments, the thickness of the first transport layer of the perovskite solar cell with a normal structure is 20 nm to 50 nm; optionally, the thickness of the first transport layer may also be, for example, 30 nm, 40 nm, or 45 nm. In the perovskite solar cell with a normal structure, since the first transport layer, that is, the electron transport layer, needs to be subjected to microwave annealing treatment together with the perovskite active layer, and there are components in the electron transport layer that are unstable to microwaves, the thickness of the electron transport layer needs to be controlled within a suitable range to avoid loss of the electron transport layer caused by microwave annealing while not having too much negative impact on the overall thickness of the battery.

[0091] In some embodiments, the material of the base layer includes glass and / or polymer; optionally, the polymer includes one or more of polyvinyl alcohol (PVA), polyethylene terephthalate (PET), polyimide (PI), polyethylene naphthalate (PEN), and polydimethylsiloxane (PDMS).

[0092] In some embodiments, the material of the first electrode includes a transparent conductive oxide material, such as ITO, FTO, etc.

[0093] In some embodiments, the material of the second electrode includes a metal conductive material and / or a transparent conductive oxide material. The metal conductive material can be, for example, gold, silver, copper, etc., and the transparent conductive oxide material can be, for example, ITO, FTO, etc.

[0094] In some embodiments, the material of the hole transport layer includes one or more of 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), poly(triarylamine) (PTAA), poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS), NiO x and WO3.

[0095] In some embodiments, the material of the charge transport layer includes one or more of imide compounds, quinone compounds, fullerenes and their derivatives, methoxytriphenylamine-fluoromethylformamidine (OMeTPA-FA), calcium titanate (CaTiO3), lithium fluoride (LiF), calcium fluoride (CaF2), poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid (PEDOT:PSS), poly(3-hexylthiophene) (P3HT), triphenylene-based triphenylamine (H101), 3,4-ethylenedioxythiophene-methoxytriphenylamine (EDOT-OMeTPA), N-(4-aniline)carbazole-spirobifluorene (CzPAF-SBF), polythiophene, metal oxides, SiO2, SrTiO3, CuSCN; wherein, the metal in the metal oxide includes one or more of Mg, Ni, Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, and Cr.

[0096] In a third aspect of the present application, there is also provided an electrical device, including the perovskite solar cell according to one or more of the foregoing embodiments.

[0097] The present application will be further described in detail below in conjunction with specific examples and comparative examples. For the experimental parameters not specified in the following specific examples, the guidance given in the present application document shall be preferentially referred to. It is also possible to refer to the experimental manuals in the art or other experimental methods known in the art, or the experimental conditions recommended by the manufacturers. It can be understood that the instruments and raw materials used in the following examples are relatively specific, and in other specific examples, this may not be limited thereto; the weights of the relevant components mentioned in the embodiments of the present application specification not only can refer to the specific contents of each component, but also can represent the proportional relationship between the weights of each component. Therefore, as long as the contents of the relevant components in the embodiments of the present application specification are scaled up or down in proportion, they are within the scope disclosed in the embodiments of the present application specification. Specifically, the weights described in the embodiments of the present application specification can be chemical and chemical engineering field well-known mass units such as μg, mg, g, kg, etc.

[0098] Example 1

[0099] Component structure: Transverse structure, FTO / NiOx / FA 0.95 Cs 0.05 PbI3 / C60 / BCP / Ag

[0100] (1) Preparation of the base layer and the first electrode:

[0101] An FTO conductive glass with a specification of 30 cm * 30 cm was used to etch P1 with an infrared laser. The width of P1 was 30 μm. The entire glass was divided into 44 sub-cells along the long side direction in sequence. The series resistance of different sub-cells was greater than 10 MΩ. The upper and lower 10 mm were used as the welding areas of the component; the surface of the etched conductive glass was cleaned twice with acetone and isopropanol in sequence, immersed in deionized water for ultrasonic treatment for 10 min, dried in a blast drying oven, and then placed in a drying room (humidity below 2%), and it was used as the first electrode;

[0102] (2) Preparation of the hole transport layer:

[0103] The cleaned conductive glass was placed in a magnetron sputtering device to deposit a layer of NiO x , with a film thickness of about 15 nm. This film layer was used as the hole transport layer;

[0104] (3) Preparation of the perovskite active layer:

[0105] PbI2, FAI (FA = formamidinium cation), and CsI were mixed in proportion in a normal temperature and dry environment. The mixture was stirred in DMF (N,N-dimethylformamide) for 4 h to prepare a 1.1 mol / L FA 0.95 Cs 0.05 PbI3 perovskite precursor solution;

[0106] After filtering the precursor solution with a 0.22-μm organic filter head, it was coated on the hole transport layer prepared in step (2) by a slot coating process to obtain a 3.33-μm-thick perovskite wet film; most of the solvent in the perovskite wet film was removed by blowing with a wind knife, and the blowing gas was nitrogen with a nitrogen pressure of 1 MPa to obtain a 600-nm-thick perovskite film; the perovskite film was subjected to microwave annealing treatment at 2450 MHz, 650 W in a microwave and at a temperature of 150 °C for 1 min to obtain a perovskite active layer;

[0107] (4) Preparation of the charge transport layer:

[0108] The semi-finished product obtained in step (3) was placed in a vacuum thermal evaporation equipment, and the vacuum was pumped to 4×10 -4 Pa, and 30 nm of C60 and 8 nm of BCP (CAS No. 4733-39-5) were sequentially deposited as the charge transport layer;

[0109] (5) Preparation of the second electrode:

[0110] Continuing in the vacuum thermal evaporation equipment, 10 nm of Ag was deposited on the surface of the charge transport layer obtained in step (4), and after breaking the vacuum, it was taken out. P2 was laser-etched with a width of 150 μm and etched to the FTO layer in depth, and the interval between P2 and P1 was 20 μm; then the substrate was placed in the evaporation equipment again and the vacuum was pumped to 4×10 -4 Pa and then a layer of Ag with a thickness of about 80 nm was continuously deposited; after cooling, it was taken out after breaking the vacuum. P3 was laser-etched with a width of 15 μm and etched to the FTO layer in depth, and the interval between P3 and P2 was 20 μm, and the positions of the etching lines were P1 / P2 / P3 in sequence; infrared edge cleaning was used to etch 10 mm on both sides of the component.

[0111] Example 2

[0112] It is basically the same as Example 1, except that the specification of the FTO conductive glass is 0.5 m×1 m.

[0113] Example 3

[0114] It is basically the same as Example 1, except that the specification of the FTO conductive glass is 1 m×2 m.

[0115] Example 4

[0116] It is basically the same as Example 1, except that the composition of the perovskite active layer is FA 0.5 Cs 0.5 PbI3.

[0117] Example 5

[0118] Basically the same as Example 1, except that the perovskite active layer is composed of FAPbI3.

[0119] Example 6

[0120] Basically the same as Example 1, except that the perovskite active layer is composed of CsPbI3.

[0121] Example 7

[0122] Basically the same as Example 1, except that in step (3), most of the solvent in the perovskite wet film is removed by an air knife, and the thickness of the perovskite thin film is 850 nm. 0.95 Cs 0.05 Pb(Br 0.2 I 0.8 )3.

[0123] Example 8

[0124] Basically the same as Example 1, except that in step (3), most of the solvent in the perovskite wet film is removed by an air knife, and the thickness of the perovskite thin film is 320 nm.

[0125] Example 9

[0126] Basically the same as Example 1, except that in step (3), most of the solvent in the perovskite wet film is removed by an air knife, and the thickness of the perovskite thin film is 320 nm.

[0127] Examples 10 - 27

[0128] Basically the same as Example 1, except that in step (3), there are differences in parameters such as the power of the microwave, the temperature and time of the microwave annealing treatment, as shown in Table 1 for details.

[0129] Example 28

[0130] Component structure: Formal structure, PET / ITO / SnO2 / FA 0.95 Cs 0.05 PbI3 / Spiro-OMeTAD / Au

[0131] (1) Preparation of the base layer and the first electrode:

[0132] Sputter a layer of ITO conductive glass (about 400 nm) on a PET with a specification of 30 cm * 30 cm, use infrared laser to etch P1, the width of P1 is 30 μm, divide the whole piece of glass into 44 sub-cells along the long side direction in turn, the series resistance of different sub-cells is greater than 10 MΩ, and 10 mm at the top and bottom are used as the welding areas of the component; wash the surface of the etched conductive glass with acetone and isopropyl alcohol 2 times in turn, immerse it in deionized water for ultrasonic treatment for 10 min, then dry it in a blast drying oven and place it in a drying room (humidity below 2%), and use it as the first electrode;

[0133] (2) Preparation of charge transport layer:

[0134] Put the substrate and electrode prepared in step (1) into a chemical solution deposition equipment for chemical deposition (CBD deposition), and deposit 50 nm of SnO2 on the surface of the first electrode as the charge transport layer;

[0135] (3) Preparation of perovskite active layer:

[0136] Mix PbI2, FAI (FA = formamidinium cation), and CsI in proportion in a dry environment at room temperature. Stir the mixture in DMSO (dimethyl sulfoxide) for 3 h to prepare a 1.3 mol / L FA 0.95 Cs 0.05 CsPbI3 perovskite precursor solution;

[0137] After filtering the precursor solution through a 0.22 μm organic filter head, coat it on the hole transport layer prepared in step (2) by slit coating process to obtain a 5.7 μm thick perovskite wet film; perform vacuum drying treatment under a vacuum degree of 1.0 Pa to remove most of the solvents in the perovskite wet film to obtain a 600 nm thick perovskite film; perform microwave annealing treatment on the perovskite film in a microwave of 2450 MHz and 450 W at a temperature of 148 °C for 3 min to obtain the perovskite active layer;

[0138] (4) Preparation of hole transport layer:

[0139] Deposit a layer of Spiro-OMeTAD with a film thickness of about 20 nm on the surface of the perovskite active layer prepared in step (3). This film layer serves as the hole transport layer;

[0140] (5) Preparation of the second electrode:

[0141] In a vacuum thermal evaporation equipment, evacuate to 4×10 -4 Pa, deposit 10 nm of Au on the surface of the hole transport layer prepared in step (4), take it out after breaking the vacuum, laser etch P2, the width of P2 is 150 μm, etch the depth to the FTO layer, and the interval between P2 and P1 is 20 μm; then put the substrate into the evaporation equipment again and evacuate to 4×10 -4 Pa and continue to deposit a layer of Au with a thickness of about 80 nm; after cooling, take it out after breaking the vacuum, laser etch P3 with a P-second green laser, the width of P3 is 15 μm, etch the depth to the FTO layer, and the interval between P3 and P2 is 20 μm, and the positions of the etching lines are P1 / P2 / P3 in sequence; use infrared edge cleaning to etch 10 mm on both sides of the component.

[0142] Comparative Examples 1 - 3

[0143] Most of the parameters respectively correspond to Examples 1 to 3 in sequence. The difference is that in step (3), for Comparative Examples 1 to 3, hot plate contact annealing treatment is used instead of microwave annealing treatment. The hot plate annealing temperature is 100 °C, and the annealing treatment time is 10 min.

[0144] Comparative Example 4

[0145] It is basically the same as Example 1, except that the specification of the FTO conductive glass is 4 cm * 5 cm, and in step (3), the microwave power is adjusted to 50 W, and the annealing treatment time is adjusted to 0.5 min.

[0146] Comparative Example 5

[0147] It is basically the same as Example 1, except that the composition of the perovskite active layer is MAPbI3 (MA = methylammonium cation).

[0148] Characterization test:

[0149] Under normal temperature and pressure, using a standard light source of AM1.5G (1000 W / m 2 ) as the sunlight simulation light source, a four-channel digital source meter (Keithley 2440) is used to measure the volt-ampere characteristic curves of the components prepared in each example and comparative example under the illumination of the light source, and the short-circuit current density Jsc, open-circuit voltage Voc, and fill factor FF (Fill Factor) of the components are obtained. From this, the energy conversion efficiency Eff (Efficiency) of the components is obtained.

[0150] Table 1

[0151]

[0152]

[0153] Analyzing the data in Table 1 and comparing Examples 1 to 3, it can be seen that under the same microwave annealing process parameters, the performance of components with different areas will vary; in Comparative Example 4, the area of the component is lower than the lower limit of 0.003 m 2 , even if the microwave power is adjusted to the lower limit of 50 W and the microwave annealing treatment time is reduced to 0.5 min, it will still cause over-annealing, with a smaller grain size, and even pores will appear between the grains, which will significantly reduce the battery performance ( Figure 3 ).

[0154] By comparing Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 3 and Comparative Example 3 respectively, it can be seen that adopting the traditional hot plate annealing process requires a lower annealing temperature to avoid local overheating as much as possible, with a long annealing time, low efficiency, and the comprehensive performance of the prepared battery is also significantly inferior to the microwave annealing process. In addition, comparing Figure 1(Example 1) and Figure 2 From (Comparative Example 1), it can be seen that the perovskite active layer obtained by hot plate annealing treatment has relatively small grains, mostly between 100 nm and 300 nm, while the grains obtained by microwave annealing treatment in Example 1 are larger. Except for the smaller grains filling at the seams, the grain size of the main part can be maintained at 1 μm to 2 μm. This is an important reason for the relatively high performance of the battery prepared in Example 1.

[0155] By comparing Example 1 and Comparative Example 5, it can be seen that when A only contains pure methylammonium cations, it is not applicable to the preparation process of this application. The methylammonium cations will be unstable and decompose under these process parameters, thus greatly affecting the performance of the battery, and the energy conversion efficiency is very low, unable to meet the actual use requirements.

[0156] By comparing Example 1 and Examples 4 - 6, it can be seen that when using a combination of methylammonium cations and cesium ions, the overall performance is better than that of using only methylammonium cations or only cesium ions alone. This is because a relatively large content of methylammonium cations helps to reduce the bandgap, and a relatively large content of cesium ions helps to improve the stability of perovskite. Therefore, when the two are used in combination, the balance between the bandgap and stability can be taken into account, thereby improving the comprehensive performance of the battery. By comparing Example 1 and Example 4, it can be seen that when the dosage ratio of methylammonium cations is within the preferred range of 70% - 95%, the battery performance can be further improved.

[0157] By comparing Example 1 and Example 7, it can be seen that introducing an appropriate amount of bromide ions does not have a great negative impact on the electrical performance of perovskite solar cells, but the introduction of bromide ions can effectively improve the stability of the battery in a high humidity environment. Therefore, a certain amount of bromide ions can be introduced according to actual use requirements.

[0158] By comparing Example 1 and Examples 8 - 9, it can be seen that when the thickness ratio of the perovskite wet film to the perovskite thin film is maintained within a suitable range, the amount of residual solvent in the thin film is appropriate, and microwave annealing can be better carried out. When there is more residual solvent (Example 8), there is still a certain amount of solvent residue in the inner layer after annealing; when there is less residual solvent (Example 9), the grains of the perovskite active layer have not grown well and the solvent has evaporated, resulting in holes in the active layer. Both of these situations will have an adverse impact on the battery performance to a certain extent. The technical features of the above-described embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combinations of these technical features do not conflict, they should all be considered as the scope described in this specification.

[0159] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims, and the description and the drawings can be used to explain the content of the claims.

Claims

1. A preparation method of a perovskite solar cell, characterized in that, It includes the following steps: Provide a base layer having a first electrode, and prepare a perovskite wet film on the first electrode using a perovskite solution; Perform a crystallization treatment on the perovskite wet film to obtain a perovskite thin film with some solvent remaining; Perform a microwave annealing treatment on the perovskite thin film to prepare a perovskite active layer; Prepare a second electrode on the perovskite active layer; Among them, the chemical formula of the perovskite is denoted as ABX3, where A includes formamidinium cations and / or Cs + , B includes Pb 2+ , Sn 2 + , Ge 2+ , Co 2+ , Fe 2+ , Mn 2+ , Cu 2+ and / or Ni 2+ One or more of them, and X includes Br - and / or I - ; The area of the perovskite thin film is 0.01 m 2 to 5 m 2 .

2. The preparation method according to claim 1, wherein, A comprises formamidinium cations and Cs + , and the proportion of formamidinium cations in A is 70% to 95%.

3. The preparation method according to claim 1, wherein Br in X - The proportion of the amount is 0 to 50%.

4. The preparation method according to claim 3, characterized in that, Br in X - The proportion by quantity is 0 to 20%.

5. The preparation method according to claim 1, wherein The process parameters of the microwave annealing treatment satisfy at least one of (a) to (d): (a). The microwave frequency is 890 MHz to 940 MHz or 2400 MHz to 2500 MHz; (b). The microwave power is 50 W to 5000 W; (c). The annealing treatment time is 0.5 min to 20 min; (d). The annealing treatment temperature is 80 °C to 200 °C.

6. The preparation method according to any one of claims 1 to 5, characterized in that, When the thickness ratio of the obtained perovskite thin film to the initial perovskite wet film is 1:4 to 10, stop the crystallization treatment.

7. The preparation method according to any one of claims 1 to 5, characterized in that, The perovskite wet film is formed by coating or inkjet printing; and / or In the perovskite solution, the molar concentration of ABX3 is 0.7 mol / L to 1.3 mol / L.

8. The preparation method according to claim 7, characterized in that, The thickness of the perovskite wet film is 2.8 μm to 3.4 μm.

9. The preparation method according to any one of claims 1 to 5, characterized in that, The dipole moment of the part of the solvent remaining in the perovskite thin film is 0.1 to 0.

9.

10. The preparation method according to claim 9, characterized in that, The solvent in the perovskite solution includes one or more of N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide.

11. The preparation method according to any one of claims 1 to 5, characterized in that, The methods for crystallizing the perovskite wet film include vacuum drying treatment and / or air knife blowing treatment; the degree of vacuum for the vacuum drying treatment is 1.0 Pa to 10 3 Pa; the pressure of the blowing gas for the air knife blowing treatment is 0 to 2.0 MPa.

12. The preparation method according to any one of claims 1 to 5, characterized in that, It further includes the following steps: Form a first transport layer on the first electrode, and the perovskite wet film is formed on the first transport layer; and / or Form a second transport layer on the perovskite active layer, and the second electrode is formed on the second transport layer.

13. A perovskite solar cell, characterized in that, Obtained by the preparation method according to any one of claims 1 to 12.

14. The perovskite solar cell according to claim 13, wherein, The perovskite solar cell includes a base layer, a first electrode, a first transport layer, the perovskite active layer, a second transport layer, and a second electrode that are sequentially stacked.

15. The perovskite solar cell according to claim 14, wherein, The perovskite solar cell is of an inverted structure, the first transport layer is a hole transport layer, and the second transport layer is a charge transport layer.

16. The perovskite solar cell according to claim 14, wherein The perovskite solar cell is of a normal structure, the first transport layer is a charge transport layer, and the second transport layer is a hole transport layer.

17. The perovskite solar cell according to any one of claims 14 to 16, characterized in that, The thickness of the first transport layer is 20 nm to 50 nm.

18. An electrical device, characterized in that, It includes the perovskite solar cell according to any one of claims 13 to 17.

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