Solar cell and preparation method thereof, electric equipment and power generation equipment

Abstract

The invention discloses a solar cell and a preparation method thereof, electric equipment and power generation equipment, the solar cell at least comprises a perovskite layer and a ferroelectric layer, and the perovskite layer comprises iodide ions and lead ions; the ferroelectric layer comprises a compound with the following chemical formula: # imgabs0 #, n = 1-3, R1 is H or NH3, R2 is H or NH2, R1 and R2 are not H at the same time, and X comprises at least one of Cl, I and Br. The ferroelectric layer can polarize the upper interface of the perovskite layer, enhance the built-in electric field and improve the open-circuit voltage, and chemical groups in the ferroelectric layer can passivate the defects of the upper interface of the perovskite layer, so that the existence of the ferroelectric layer can improve the interface transmission performance, thereby improving the photoelectric conversion efficiency and stability of the solar cell.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and in particular to a solar cell and a preparation method thereof, an electrical device and a power generation device. Background Art

[0002] As a key technology in the field of new energy, solar cells have expanded beyond the military and aerospace sectors into numerous fields, including industry, commerce, agriculture, communications, home appliances, and public utilities. Perovskite solar cells are one of the most promising and promising solar cells, boasting high efficiency, environmental friendliness, and low cost.

[0003] However, the non-radiative recombination of photogenerated carriers at the perovskite interface can reduce interface transport properties, causing the photoelectric conversion efficiency of perovskite solar cells to fall far below the theoretical limit, while also failing to meet operational standards. The above statements are intended only to provide background information related to this application and do not necessarily constitute prior art. Summary of the Invention

[0004] The main technical problem solved by this application is to provide a solar cell and its preparation method, electrical equipment and power generation equipment, which can improve the interface transmission performance and thereby enhance the photoelectric conversion efficiency and stability of the solar cell.

[0005] To solve the above technical problems, the present application adopts a technical solution: providing a solar cell, the cell comprising at least a perovskite layer and a ferroelectric layer, the ferroelectric layer being located on the surface of the perovskite layer, wherein the perovskite layer comprises iodine ions and lead ions; and the ferroelectric layer comprises a compound having the following chemical formula: wherein n=1-3, R1 is H or NH3; R2 is H or NH2, and R1 and R2 are not both H; and X comprises at least one of Cl, I, and Br. The ferroelectric layer can polarize the upper interface of the perovskite layer, enhancing the built-in electric field, promoting the separation of photogenerated electron-hole pairs, and increasing the open-circuit voltage. Simultaneously, the chemical groups in the ferroelectric layer can passivate defects at the upper interface of the perovskite layer. Therefore, the presence of the ferroelectric layer can inhibit the non-radiative recombination of photogenerated carriers at the perovskite interface, improving the interface transport properties, and thereby enhancing the photoelectric conversion efficiency and stability of the solar cell.

[0006] Furthermore, the difluorinated groups contained in the ferroelectric layer can increase the surface hydrophobicity of the perovskite layer and extend the service life of the solar cell.

[0007] In one embodiment, the cations of the ferroelectric layer include any one of the following structures (1) to (4): The ferroelectric layer containing the above four cations can polarize the upper interface of the perovskite layer, increase the open circuit voltage, and passivate the defects of the upper interface of the perovskite layer, thereby improving the interface transmission performance of the solar cell and improving the photoelectric conversion efficiency and stability.

[0008] In one embodiment, the ferroelectric layer forms a one-dimensional or two-dimensional perovskite structure on the surface of the perovskite layer. The one-dimensional or two-dimensional perovskite structure of the ferroelectric layer is different from the perovskite layer of the perovskite layer. The one-dimensional or two-dimensional perovskite structure of the ferroelectric layer has ferroelectric properties, allowing the ferroelectric layer to spontaneously polarize and enhance the built-in electric field.

[0009] In one embodiment, the solar cell is an inverted perovskite solar cell or a tandem cell comprising an inverted perovskite solar cell, wherein the ferroelectric layer is located on the upper surface of the perovskite layer. Tandem cells include perovskite-perovskite tandem cells, perovskite-crystalline silicon tandem cells, and perovskite-heterojunction tandem cells, thereby expanding the application range of the additive.

[0010] In one embodiment, the thickness of the ferroelectric layer is 5 nm to 30 nm. Through the above configuration, the built-in electric field can be enhanced by ferroelectric polarization while the conductive performance of the solar cell can be taken into consideration.

[0011] In one embodiment, the thickness of the perovskite layer is 400 nm to 500 nm. Within this thickness range, the perovskite layer has a relatively high absorption efficiency and photoelectric conversion efficiency for sunlight, which is beneficial for improving the working efficiency of the solar cell.

[0012] To solve the above technical problems, another technical solution adopted in the present application is to provide a method for preparing a solar cell, comprising: providing a substrate structure for arranging a perovskite layer; arranging the perovskite layer on the substrate structure, the perovskite layer comprising iodide ions and lead ions; and arranging a ferroelectric layer on the surface of the perovskite layer, the ferroelectric layer comprising a compound having the following chemical formula: Wherein, n=1-3, R1 is H or NH3; R2 is H or NH2, and R1 and R2 are not both H; and X comprises at least one of Cl, I, and Br. In a solar cell prepared by the above method, the ferroelectric layer in the solar cell can polarize the upper interface of the perovskite layer, enhancing the built-in electric field and increasing the open-circuit voltage. Simultaneously, the chemical groups in the ferroelectric layer can passivate defects in the upper interface of the perovskite layer, thereby improving the interface transmission performance and thereby enhancing the photoelectric conversion efficiency and stability of the solar cell. Furthermore, the difluorinated groups contained in the ferroelectric layer can increase the surface hydrophobicity of the perovskite layer, extending the service life of the solar cell.

[0013] In one embodiment, the step of providing a perovskite layer on the substrate structure includes providing a perovskite precursor solution on the substrate structure and heat treating the solution to form the perovskite layer, wherein the perovskite precursor solution includes iodide ions and lead ions. This method can form a well-formed perovskite crystal film and provide binding sites for the ferroelectric layer.

[0014] In one embodiment, the step of providing a ferroelectric layer on the surface of the perovskite layer includes providing a ferroelectric precursor solution on the surface of the perovskite layer and forming the ferroelectric layer after heat treatment, wherein the ferroelectric precursor solution includes a compound having the following chemical formula: wherein n=1-3, R1 is H or NH3; R2 is H or NH2, and R1 and R2 are not both H; and X comprises at least one of Cl, I, and Br. Through the above method, the ferroelectric precursor reacts with the lead iodide in the perovskite layer to form a ferroelectric layer having a one-dimensional or two-dimensional perovskite structure. The ferroelectric layer enhances the built-in electric field through ferroelectric polarization, thereby increasing the open-circuit voltage. Simultaneously, the chemical groups in the ferroelectric layer can passivate defects on the interface of the perovskite layer, thereby improving the interface transmission performance.

[0015] In one embodiment, the concentration of the ferroelectric precursor solution is 0.1 mg / mL to 5.0 mg / mL. Through the above configuration, the conductive performance of the solar cell can be taken into consideration while enhancing the built-in electric field through ferroelectric polarization.

[0016] In one embodiment, the solvent of the ferroelectric precursor solution includes at least one of isopropyl alcohol, methanol, and ethanol. The solubility of the solute in the ferroelectric precursor solution is relatively high in the above solvents, which is beneficial to improving the uniformity of the ferroelectric precursor solution and the quality of the ferroelectric layer film.

[0017] In one embodiment, in the step of placing the ferroelectric precursor solution on the surface of the perovskite layer and forming the ferroelectric layer after heat treatment, the heat treatment temperature is 80° C. to 120° C. and the time is 2 min to 10 min.

[0018] To solve the above technical problems, another technical solution adopted by the present application is to provide an electrical device comprising the above battery, which has at least the same advantages as the battery.

[0019] To solve the above technical problems, another technical solution adopted by the present application is to provide a power generation device comprising the above battery. The power generation device has at least the same advantages as the battery.

[0020] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0022] Figure 1 is a schematic structural diagram of a solar cell according to one or more embodiments;

[0023] Figure 2 is a ferroelectric polarization diagram of a ferroelectric layer according to one or more embodiments;

[0024] Figure 3 is a schematic structural diagram of an inverted solar cell according to one or more embodiments;

[0025] Figure 4 This is a schematic diagram of the structure of electrical equipment in some embodiments of the present application;

[0026] Figure 5 This is a schematic structural diagram of a power generation device according to some embodiments of the present application;

[0027] In the attached figure:

[0028] 100. Solar cell; 11. First electrode; 13. Second electrode; 21. Hole transport layer; 23. Electron transport layer; 30. Perovskite layer; 40. Ferroelectric layer; 1000. Electrical device; 2000. Power generation device. DETAILED DESCRIPTION

[0029] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0031] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0032] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0033] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0034] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0035] Perovskite solar cells, with their outstanding advantages such as high photoelectric conversion efficiency, low cost, and simple fabrication, have become a promising solar cell and a hot topic of research. They can be used in lunar rovers, satellite panels, various sensors and detectors, as well as in civilian products such as wearable electronics and automotive power supplies. In many ways, perovskite solar cells have become a power source for consumer products. With the continuous expansion of perovskite solar cell applications and the flexible and foldable nature of perovskite solar cells, market demand is also growing.

[0036] It's worth noting that the contact interfaces between the functional layers of perovskite solar cells still exist. The probability of nonradiative recombination (NRR) of photogenerated carriers at these interfaces in perovskite solar cell devices is much higher than that of recombination in the bulk perovskite material. This nonradiative recombination can lead to reduced photoelectric conversion efficiency and stability of perovskite solar cells. Therefore, modifying and regulating the interfaces within the device can be an effective means of suppressing the carrier recombination rate at these interfaces and improving interface transport properties.

[0037] As one of the key interfaces in the perovskite solar cell system, the interface between the electron transport layer and the perovskite layer (ETL / Perovskite) is related to whether the photogenerated carriers can be smoothly transferred from the perovskite layer to the n-type semiconductor. The recombination problem between charges at this interface will also seriously restrict the photovoltaic performance of perovskite solar cells.

[0038] The study found that improving the interface transmission performance of solar cells can be achieved by, on the one hand, increasing the separation efficiency of photogenerated electron-hole pairs, and on the other hand, by passivating the interface defects of the perovskite layer.

[0039] In order to solve the above technical problems, the present application provides a solar cell, which includes at least a perovskite layer and a ferroelectric layer, wherein the ferroelectric layer is located on the surface of the perovskite layer, wherein the perovskite layer includes iodine ions and lead ions; and the ferroelectric layer includes a compound with the following chemical formula: Wherein, n=1-3, R1 is H or NH3; R2 is H or NH2, R1 and R2 are not H at the same time; X includes at least one of Cl, I and Br.

[0040] See also Figure 1 , Figure 1 FIG2 is a schematic diagram of the structure of a solar cell according to one or more embodiments. In one embodiment, the solar cell 100 includes a substrate layer (not shown), a first electrode 11, a hole transport layer 21, a perovskite layer 30, a ferroelectric layer 40, an electron transport layer 23, and a second electrode 13, which are stacked in sequence.

[0041] The base layer is a transparent base layer. The base layer may be made of glass and / or a polymer. Optionally, the polymer may include one or more of polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), and polydimethylsiloxane (PDMS). In some embodiments, the base layer may not be provided.

[0042] The first electrode 11 is a transparent conductive substrate with high conductivity and high visible light transmittance, and has the function of collecting charges. In some embodiments, the material of the first electrode 11 is a transparent conductive oxide material, including any one of fluorine-doped tin oxide (FTO), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), and indium-doped zinc oxide (IZO).

[0043] The hole transport layer 21 is used to transport free holes to corresponding electrodes and prevent the free holes from diffusing in the opposite direction.

[0044] In some embodiments, the material of the hole transport layer 21 includes one or more of metal oxide materials, polymer materials, organic small molecule self-assembled molecular materials and their derivatives and materials obtained by doping or passivation thereof. For example, but not limited to metal oxide materials, such as nickel oxide (NiO x2 , 1.5≥x2≥1), molybdenum oxide (MoO x3 , 3≥x3≥2.5), tungsten oxide (WO x4 , 3≥x4≥2.5); polymer materials, such as poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT:PSS); organic small molecule self-assembled molecular materials, such as carbazole or triphenylamine materials containing phosphoric acid or carboxylic acid groups, etc.

[0045] It should be noted that, in some embodiments, the solar cell 100 may not include the hole transport layer 21 .

[0046] The perovskite layer 30 is used to absorb light and directly convert light energy into electrical energy through the photoelectric effect or the photochemical effect.

[0047] The perovskite layer 30 includes a perovskite material having a photoelectric conversion function. The perovskite material absorbs photons from sunlight to generate excitation, which excites electrons in the valence band to generate photogenerated electron-hole pairs. The electron-hole pairs have a small binding energy and are easily dissociated under the action of a built-in electric field, thereby separating into free electrons and free holes, i.e., carriers.

[0048] In some embodiments, the material of the perovskite layer 30 includes, but is not limited to, perovskite.

[0049] In one embodiment, the perovskite layer includes iodide ions and lead ions. The chemical composition of the perovskite includes ABX3, wherein A is any one of an inorganic cation, an organic cation, or an organic-inorganic mixed cation, and can be a methylammonium ion (CH3NH3 + , MA + ), n-butylammonium ion (HC(NH2)2 + , FA + ), cesium ions (Cs + ) at least one of; B is any one of an inorganic cation, an organic cation, an organic-inorganic mixed cation, including at least lead ions (Pb 2+ ); X is any one of an inorganic anion, an organic anion, or an organic-inorganic mixed anion, including at least iodide ion (I - ).

[0050] The electron transport layer 23 functions to efficiently transport free electrons generated by the perovskite layer 30 , effectively block the passage of free holes, and form an ohmic contact at the interface with the light absorbing active layer.

[0051] In some embodiments, the material of the electron transport layer 23 is at least one of the following materials and their derivatives and materials obtained by doping or passivation. The electron transport material includes but is not limited to at least one of imide compounds, quinone compounds, fullerenes and their derivatives, metal oxides, semiconductor material oxides, titanates, and fluorides. Imides include at least one of perylene imide and its derivatives, naphthalene imide and its derivatives, phthalimide, succinimide, N-bromosuccinimide, glutarimide, or maleimide. Quinone compounds include at least one of benzoquinone, naphthoquinone, phenanthrenequinone, or anthraquinone. Fullerenes and their derivatives include [6,6]-phenyl C 61 Methyl butyrate (PC 61 BM), [6,6]-phenyl C 71 -Methyl butyrate (PC 71 BM), fullerene C 60 (C 60 ), Fullerene C 70 (C 70 ). The metal element in the metal oxide includes at least one of magnesium (Mg), cadmium (Cd), zinc (Zn), indium (In), lead (Pb), tungsten (W), antimony (Sb), bismuth (Bi), mercury (Hg), titanium (Ti), silver (Ag), manganese (Mn), iron (Fe), vanadium (V), tin (Sn), zirconium (Zr), strontium (Sr), gallium (Ga), and chromium (Cr). The semiconductor material oxide includes silicon oxide. The titanate includes at least one of strontium titanate and calcium titanate. The fluoride includes at least one of lithium fluoride and calcium fluoride.

[0052] It should be noted that, in some embodiments, the solar cell 100 may not include the electron transport layer 23 .

[0053] The second electrode 13 has the function of collecting free charges. In some embodiments, the electrode material of the second electrode 13 includes one or more of an organic conductive material, an inorganic conductive material, and an organic-inorganic hybrid conductive material, including silver (Ag), copper (Cu), carbon (C), gold (Au), aluminum (Al), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), indium-doped zinc oxide (IZO), etc.

[0054] In one embodiment, the solar cell provided by the present application further includes a blocking layer, which is located between the electron transport layer 23 and the second electrode 13. The blocking layer is used to block the reaction between the second electrode 13 and the perovskite, improve the reduction in device efficiency caused by the Schottky contact between the electron transport layer and the electrode, and has an energy level regulation effect. The valence band energy level of the blocking layer is low, much lower than the valence band energy level of the perovskite layer, and can effectively prevent the injection of holes. Therefore, the energy and charge loss caused by interfacial charge recombination can be reduced, thereby improving the energy conversion efficiency of the device.

[0055] Furthermore, the barrier layer material includes 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP), tin dioxide (SnO2), zinc oxide (ZnO), cerium oxide (CeO x1 , 1.5≤x1≤2) and the thickness of the barrier layer is 0.5nm~20nm.

[0056] In order to improve the interface transmission performance, in one embodiment, the solar cell further includes a ferroelectric layer 40, which is located on the surface of the perovskite layer 30, that is, the surface of the perovskite layer 30 facing the second electrode 13. The ferroelectric layer 40 includes a compound with the following chemical formula: Wherein, n=1-3, R1 is H or NH3; R2 is H or NH2; R1 and R2 are not H at the same time; X includes at least one of Cl, I and Br.

[0057] The ferroelectric layer 40 exhibits ferroelectricity. In some dielectric crystals, the structure of the unit cell causes the centers of positive and negative charges to misalign, resulting in an electric dipole moment and a non-zero electric polarization. This gives the crystal spontaneous polarization, and the direction of the electric dipole moment can be altered by an external electric field, exhibiting characteristics similar to those of ferromagnets. This property of the crystal is called ferroelectricity. The ferroelectricity of the ferroelectric layer 40 originates from the presence of a difluorinated group. Fluorine is the most electronegative element in the periodic table, and its presence can induce a phase transition in the material, thereby generating an electric dipole moment and spontaneous polarization. The induced polarization electric field of the ferroelectric layer 40 is superimposed on the built-in electric field of the perovskite layer itself, thereby enhancing the built-in electric field of the solar cell. This can further enhance the separation efficiency of photogenerated electron-hole pairs within the cell, reduce carrier interfacial recombination, and thus overcome the limited open-circuit voltage.

[0058] The ferroelectric layer 40 can also passivate the defects on the surface of the perovskite layer through specific chemical groups. - , I - Br - ) can effectively passivate the cation defects in perovskites, such as low-coordinated Pb 2+ Coordination bonding and filling I -Vacancy defects, etc., thereby reducing the non-radiative recombination loss of electrons at the interface and achieving a passivation effect; the cations (ammonium radicals, -NH3 + ) can interact with negatively charged defects at the perovskite interface through electrostatic interactions (including ionic and hydrogen bonds), thereby effectively passivating anionic defects, such as low-coordinated I in halide perovskites. - , reverse PbI3 - and cationic MA + Vacancies, etc. The passivation of defects can also reduce the interfacial recombination of carriers.

[0059] In summary, the ferroelectric layer can improve the interface transmission performance of solar cells, thereby improving the photoelectric conversion efficiency and stability of solar cells.

[0060] In addition, the difluoro group has good hydrophobicity, which enables the ferroelectric layer to protect the perovskite layer and reduce the invasion of external water vapor, which is beneficial to improving the water resistance of the perovskite layer, thereby improving the stability of solar cells and extending the service life of solar cells.

[0061] Specifically, in one embodiment, the cations of the ferroelectric layer include any one of the following structures (1) to (4): The ferroelectric layer containing the above four cations can polarize the upper interface of the perovskite layer, increase the open circuit voltage, and passivate the defects of the upper interface of the perovskite layer, thereby improving the interface transmission performance of the solar cell and improving the photoelectric conversion efficiency and stability.

[0062] In one embodiment, the ferroelectric layer 40 forms a one-dimensional or two-dimensional perovskite structure on the surface of the perovskite layer 30 .

[0063] The cations in the ferroelectric layer 40 react with the lead iodide in the perovskite layer 30 to form a stable ferroelectric layer 40 having a one-dimensional or two-dimensional halide perovskite structure. For example, the perovskite structure formed at this time is The cations in the ferroelectric layer form hydrogen bonds with the perovskite layer on one side, and the interlayer cations cross each other and interact through van der Waals forces to form a perovskite structure. The ferroelectricity of the perovskite structure mainly comes from the ordering of organic cations.

[0064] See also Figure 2 , Figure 2 The ferroelectric polarization diagram of the ferroelectric layer of one or more embodiments of the present application is shown in FIG. The horizontal axis is the applied electric field strength and the vertical axis is the polarization strength. Figure 2 It can be seen that the ferroelectric layer of the embodiment shows a ferroelectric hysteresis loop and polarization reversal under a changing electric field, indicating that the ferroelectric layer of the embodiment has ferroelectricity. Therefore, the ferroelectric layer can spontaneously polarize and enhance the built-in electric field of the solar cell.

[0065] In one embodiment, the solar cell is an inverted perovskite solar cell or a tandem cell comprising an inverted perovskite solar cell, wherein the ferroelectric layer is located on the upper surface of the perovskite layer. Tandem cells include perovskite-perovskite tandem cells, perovskite-crystalline silicon tandem cells, and perovskite-heterojunction tandem cells, expanding the application range of additives. Unlike regular solar cells, light is incident from a transparent anode in inverted solar cells; in terms of performance, inverted solar cells have excellent stability and low hysteresis.

[0066] In one embodiment, the thickness of the ferroelectric layer is 5 nm to 30 nm.

[0067] Through the above arrangement, it is possible to enhance the built-in electric field through ferroelectric polarization while taking into account the conductive performance of the solar cell.

[0068] In one embodiment, the thickness of the perovskite layer is 400 nm to 500 nm.

[0069] Properly increasing the thickness of the perovskite layer is beneficial for the perovskite material to absorb more light. At the same time, it can provide sufficient photon propagation paths, promote the separation of electrons and holes, and help improve the photoelectric conversion efficiency. However, the thickness of the perovskite layer should not be too large. If the thickness is too large, the morphology control becomes more difficult, which in turn affects the effective extraction of carrier diffusion and charge, and leads to serious non-radiative recombination and energy loss, which in turn reduces the photoelectric conversion efficiency. By setting the thickness of the perovskite layer to 400nm~500nm, it is beneficial to improve the absorption efficiency of sunlight and the photoelectric conversion efficiency of the perovskite layer, thereby improving the working efficiency of solar cells.

[0070] The present application also provides a method for preparing a solar cell, the method comprising: providing a substrate structure, the substrate structure being used to provide a perovskite layer; providing the perovskite layer on the substrate structure, the perovskite layer comprising iodide ions and lead ions; and providing a ferroelectric layer on the surface of the perovskite layer, the ferroelectric layer comprising a compound having the following chemical formula: Wherein, n=1-3, R1 is H or NH3; R2 is H or NH2, R1 and R2 are not H at the same time; X includes at least one of Cl, I and Br.

[0071] The substrate structure is a general term for the structures of the layers below the perovskite layer of the solar cell. Figure 1 The substrate structure may be a base layer (not shown), a first electrode 11 and a hole transport layer 21 stacked in sequence.

[0072] In another embodiment, the substrate structure may further include at least one of an electron blocking layer and a passivation layer. The substrate structure may also be other structures commonly used in solar cells, which are not limited here.

[0073] In one embodiment, please continue to refer to Figure 1 An electron transport layer 23 and a second electrode 13 are further provided on the substrate structure, the perovskite layer 30 and the ferroelectric layer 40 , wherein the substrate structure includes a first electrode 11 and a hole transport layer 21 .

[0074] In solar cells fabricated using this method, the ferroelectric layer in the solar cell can polarize the upper interface of the perovskite layer, enhancing the built-in electric field and raising the open-circuit voltage. Simultaneously, the chemical groups in the ferroelectric layer can passivate defects in the upper interface of the perovskite layer, thereby improving interfacial transmission properties and thereby enhancing the photoelectric conversion efficiency and stability of the solar cell. Furthermore, the difluoro groups contained in the ferroelectric layer can increase the surface hydrophobicity of the perovskite layer, extending the service life of the solar cell.

[0075] In one embodiment, the step of providing a perovskite layer on the substrate structure includes: providing a perovskite precursor solution on the substrate structure, and forming the perovskite layer after heat treatment, wherein the perovskite precursor solution includes iodine ions and lead ions.

[0076] The perovskite precursor solution is prepared by dissolving the perovskite component in an organic solvent. As previously mentioned, the chemical composition of the perovskite component includes ABX3, iodide ions, and lead ions; the organic solvent includes dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF). The iodide ions and lead ions in the perovskite component provide binding sites for the ferroelectric layer.

[0077] In one embodiment, the concentration of the perovskite precursor solution is 1.2 mol / L to 1.6 mol / L. Appropriately increasing the concentration of the perovskite precursor solution helps form high-quality perovskite films and improves the photoelectric conversion efficiency and light absorption intensity of solar cells. However, increasing the concentration of the perovskite precursor solution can lead to uneven films or unstable crystal growth. Therefore, within the perovskite precursor solution concentration range provided in this application, it is beneficial to improve the quality of the perovskite film and the photoelectric conversion efficiency and light absorption intensity of the solar cell.

[0078] A mixed solution of a perovskite precursor solution and an additive can be provided on a substrate structure by spin coating, doctor blade coating, spray coating, inkjet printing, etc., to form a perovskite film on the substrate structure.

[0079] The next step is thermal treatment, which involves placing the coated perovskite film in a high-temperature furnace or hot plate for heat treatment (also known as annealing), typically at temperatures between 100°C and 500°C. This thermal treatment promotes the growth of perovskite crystals, modulates their morphology, helps reduce defects, and improves photoelectric conversion efficiency. It also helps completely remove residual organic matter and solvents, improving the purity of the film.

[0080] In one embodiment, the step of providing a ferroelectric layer on the surface of the perovskite layer includes providing a ferroelectric precursor solution on the surface of the perovskite layer and forming the ferroelectric layer after heat treatment, wherein the ferroelectric precursor solution includes a compound having the following chemical formula: Wherein, n=1-3, R1 is H or NH3; R2 is H or NH2; R1 and R2 are not H at the same time; X includes at least one of Cl, I and Br.

[0081] The ferroelectric precursor solution consists of two parts: solute and solvent. The solute includes cations and anions. The cations include saturated ring structures with difluoro groups and ammonium groups, and the anions include Cl - , I- and Br - At least one of the above is used to form a ferroelectric layer.

[0082] In one embodiment, the concentration of the ferroelectric precursor solution is 0.1 mg / mL to 5.0 mg / mL, for example, it can be 0.1 mg / mL, 0.2 mg / mL, 1.0 mg / mL, 2.0 mg / mL, 3.0 mg / mL, 4.0 mg / mL, 4.5 mg / mL, 5.0 mg / mL, etc., or a range consisting of any two of the above values, for example, it can be 0.1 mg / mL to 1.0 mg / mL, 0.2 mg / mL to 2.0 mg / mL, 4.5 mg / mL to 5.0 mg / mL, etc.

[0083] The concentration of the ferroelectric precursor solution is related to the ferroelectric substance content of the ferroelectric layer. When the concentration of the ferroelectric precursor solution is increased, the ferroelectric substance content increases. In order to give full play to the role of the ferroelectric layer in enhancing the built-in electric field through spontaneous polarization, the concentration of the ferroelectric precursor solution is greater than or equal to 0.1 mg / mL. However, when the concentration of the ferroelectric precursor solution exceeds 5.0 mg / mL, since the ferroelectric layer cannot conduct electricity, it will cause electron transport to be suppressed. Therefore, when the concentration of the ferroelectric precursor solution is within the above range, it is possible to enhance the built-in electric field and passivate interface defects through ferroelectric polarization while taking into account the conductive properties of the solar cell.

[0084] In one embodiment, the solvent of the ferroelectric precursor solution includes at least one of isopropyl alcohol (IPA), methanol (MT), and ethanol (EA). These solvents have good solubility for the solutes in the ferroelectric precursor solution at room temperature, thereby improving the uniformity of the ferroelectric precursor solution and the quality of the ferroelectric layer film in subsequent fabrication processes. In some embodiments, the solvent of the ferroelectric precursor solution may be isopropyl alcohol.

[0085] The ferroelectric precursor solution can be applied to the perovskite layer surface by spin coating, doctor blade coating, etc. to form a uniform ferroelectric precursor solution film. A heat treatment is then performed to accelerate the volatilization of the solvent and the formation rate of the ferroelectric layer.

[0086] In one embodiment, the heat treatment temperature is 80° C. to 120° C., and the time is 2 min to 10 min. The above-mentioned configuration is helpful to accelerate the reaction rate and improve the crystal quality of the ferroelectric layer.

[0087] Through the above method, the ferroelectric precursor liquid reacts with the lead iodide in the perovskite layer to form a ferroelectric layer with a one-dimensional or two-dimensional perovskite structure, so that the ferroelectric layer enhances the built-in electric field through ferroelectric polarization and increases the open circuit voltage. At the same time, the chemical groups in the ferroelectric layer can passivate the defects on the interface of the perovskite layer, thereby improving the interface transmission performance.

[0088] For example, see Figure 3 , Figure 3 The structure of an inverted solar cell according to one or more embodiments is schematically shown. The method for preparing the inverted solar cell includes the following steps: providing a first electrode, wherein the material of the first electrode is indium tin oxide (ITO) glass; using magnetron sputtering to prepare a hole transport layer on the ITO, wherein the material of the hole transport layer is nickel oxide (NiO) with a thickness of 30nm, and the first electrode and the hole transport layer constitute a substrate structure; spin coating or scraping a mixed solution of a perovskite precursor solution and an additive on the substrate structure to form a perovskite film, and forming a perovskite layer after heat treatment, wherein the perovskite component is Cs (0-0.05) FA (0.8-0.95) MA (0-0.10) Pb (0.5-1.0) Sn (0.0-0.5) I (2.0-3.0) Br (0.0-1.0) The thickness of the perovskite film is 400nm to 500nm; 5nm to 30nm of ferroelectric precursor solution is spin-coated or scraped on the perovskite layer, and a ferroelectric layer is formed after heat treatment; then 20nm of fullerene (C 60 ) or a fullerene derivative layer (PCBM) as an electron transport layer, and 5nm of 2,9-dimethyl-4,7-biphenyl-1,10-o-phenanthroline (BCP) is thermally evaporated as a blocking layer (not shown); finally, a second electrode is thermally evaporated on the blocking layer. The material of the second electrode is copper with a thickness of 100nm.

[0089] See also Figure 4 The present application also provides an electrical device 1000, comprising the above-mentioned solar cell 100 or a solar cell prepared by the above-mentioned solar cell preparation method.

[0090] In the present application, the solar cell 100 serves as a power source for the electrical device 1000; alternatively, the solar cell 100 can serve as an energy storage unit for the electrical device 1000. For example, the electrical device 1000 can be a lighting element, a display element, or a car.

[0091] See also Figure 5 The present application further provides a power generation device 2000, comprising the aforementioned solar cell 100 or a solar cell prepared by the aforementioned solar cell preparation method. The power generation device 2000 can be used for generating electricity and comprises at least the solar cell 100.

[0092] The beneficial effects of the present application are further illustrated below with reference to the examples.

[0093] In order to make the technical problems, technical solutions and beneficial effects solved by the embodiments of the present application clearer, the following will be further described in detail with reference to the embodiments and drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its applications. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0094] 1. Fabrication of Perovskite Solar Cell Devices:

[0095] Example 1:

[0096] (1) ITO conductive glass cleaning

[0097] The etched ITO glass was ultrasonically cleaned in a surfactant aqueous solution, distilled water, acetone, and alcohol for 30 minutes, and finally dried with nitrogen for later use.

[0098] (2) Preparation of NiO hole transport layer

[0099] In this example, NiO was used as the hole transport layer material. The cleaned ITO glass was plasma treated for 3 minutes to enhance the subsequent NiO bonding. Nickel oxide (30 nm thick) was then deposited on the ITO using magnetron sputtering.

[0100] (3)Cs 0.05 FA 0.95 Preparation of PbI3 perovskite layer

[0101] In a glove box, Cs with a concentration of 1.4 mol / L was added dropwise to the upper surface of the substrate coated with the NiO hole transport layer. 0.05 FA 0.95 The PbI3 perovskite precursor solution was spin-coated at 4000 rpm for 30 seconds. After spin coating, it was transferred to a hot plate at 100°C for annealing and crystallization for 10 minutes to obtain a uniform and dense perovskite film with a thickness of 500 nm.

[0102] (4) Preparation of ferroelectric layer

[0103] Spin-coat the perovskite film with a concentration of 1 mg / mL The isopropanol solution was spin-coated at 3000 rpm for 30 seconds. After spin-coating, it was transferred to a hot plate at 100°C for annealing and crystallization for 5 minutes to obtain a ferroelectric layer film with a thickness of 10 nm.

[0104] (5)C 60 Preparation of electron transport layer

[0105] The device coated with the ferroelectric layer is transferred to the evaporation chamber. 60 Place the evaporation boat in the evaporation chamber and close the door. Vacuum to 10 -4 Pa, with The speed of evaporating 20nm C 60 Electron transport layer.

[0106] (6) Preparation of BCP barrier layer

[0107] On the electron transport layer A 5 nm BCP barrier layer was evaporated at a rate of 100 Å.

[0108] (7) Preparation of Cu electrode

[0109] The copper particles are placed in the evaporation boat. A 100nm copper electrode was evaporated at a speed of 1000 nm, and the vacuum was stopped before taking it out, and finally a perovskite solar cell was obtained, which was marked as cell S1.

[0110] Example 2:

[0111] On the basis of Example 1, the chemical composition of the ferroelectric layer is changed, and in step (4) Replace with The obtained perovskite solar cell is marked as cell S2.

[0112] Comparative Example:

[0113] Based on Example 1, in step (4) Replace with The replaced molecular structure does not contain a difluorinated group, and the resulting perovskite solar cell is labeled cell D1.

[0114] 2. Device performance characterization:

[0115] 1. Short-circuit current, open-circuit voltage, initial efficiency

[0116] Scan the volt-ampere characteristic curve under a sunlight intensity (AM1.5), control the output of the source meter, scan the IV curve, and obtain the main parameters: short-circuit current (I sc ), open circuit voltage (V oc ), initial efficiency (%).

[0117] 2. Efficiency after 100 hours of maximum power light aging

[0118] Under a sunlight intensity of one sun (AM1.5), control the output voltage of the source meter to the maximum power point, measure the current, obtain the maximum power, and measure the maximum power output every 5 minutes.

[0119] The test results are shown in Table 1.

[0120] Table 1 Test parameters of various embodiments and comparative examples

[0121]

[0122] Note: The concentration of the ferroelectric layer substances in the ferroelectric precursor solution in Table 1 is 1 mg / mL, and the solvent of the ferroelectric precursor solution is IPA.

[0123] 3. Analysis of perovskite solar cell device performance test results

[0124] Please see Table 1.

[0125] Compared to the comparative example, the cations of the ferroelectric layer materials in Examples 1 and 2 included difluorinated groups, significantly improving the performance of the perovskite solar cell devices. The open-circuit voltage increased to 1.17V and 1.16V, respectively, and the initial efficiency increased to 23.0% and 22.7%, respectively. This demonstrates that the examples significantly improve the open-circuit voltage and photoelectric conversion efficiency of the perovskite solar cell devices.

[0126] In the comparative example, the efficiency of cell D1 decreased by 0.9% after 100 hours of maximum power light aging, while the efficiency of the corresponding cell devices in Examples 1 and 2 only decreased by 0.3% and 0.2%, respectively. This shows that the stability of the perovskite solar cell devices in the examples herein has been significantly improved.

[0127] The above description is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A solar cell, characterized in that: At least comprising a perovskite layer and a ferroelectric layer, wherein the ferroelectric layer is located on the surface of the perovskite layer, wherein the perovskite layer comprises iodine ions and lead ions; The ferroelectric layer includes a compound having the following chemical formula: wherein n=1-3, R1 is H or NH3; R2 is H or NH2, R1 and R2 are not H at the same time; X includes at least one of Cl, I, and Br.

2. The solar cell according to claim 1, wherein The cations of the ferroelectric layer include any one of the following structures (1) to (4):

3. The solar cell according to claim 1 or 2, wherein: The ferroelectric layer forms a one-dimensional or two-dimensional perovskite structure on the surface of the perovskite layer.

4. The solar cell according to any one of claims 1 to 3, wherein The solar cell is an inverse perovskite solar cell or a stacked cell comprising an inverse perovskite solar cell, and the ferroelectric layer is located on the upper surface of the perovskite layer.

5. The solar cell according to any one of claims 1 to 4, wherein The thickness of the ferroelectric layer is 5nm to 30nm.

6. The solar cell according to any one of claims 1 to 5, wherein The thickness of the perovskite layer is 400nm to 500nm.

7. A method for preparing a solar cell, characterized in that: include: Providing a substrate structure for arranging a perovskite layer; Disposing the perovskite layer on the substrate structure, wherein the perovskite layer includes iodine ions and lead ions; A ferroelectric layer is provided on the surface of the perovskite layer, wherein the ferroelectric layer includes a compound having the following chemical formula: Wherein, n=1-3, R1 is H or NH3; R2 is H or NH2, R1 and R2 are not H at the same time; X includes at least one of Cl, I and Br.

8. The method for preparing a solar cell according to claim 7, wherein: The step of providing the perovskite layer on the substrate structure comprises: A perovskite precursor solution is placed on the substrate structure, and the perovskite layer is formed after heat treatment. The perovskite precursor solution includes iodine ions and lead ions.

9. The method for preparing a solar cell according to claim 7 or 8, wherein: The step of providing a ferroelectric layer on the surface of the perovskite layer comprises: A ferroelectric precursor solution is placed on the surface of the perovskite layer and then subjected to heat treatment to form the ferroelectric layer. The ferroelectric precursor solution includes a compound having the following chemical formula: Wherein, n=1-3, R1 is H or NH3; R2 is H or NH2, R1 and R2 are not H at the same time; X includes at least one of Cl, I and Br.

10. The method for preparing a solar cell according to claim 9, wherein: The concentration of the ferroelectric precursor solution is 0.1 mg / mL to 5.0 mg / mL.

11. The method for preparing a solar cell according to claim 9 or 10, wherein: The solvent of the ferroelectric precursor solution includes at least one of isopropyl alcohol, methanol and ethanol.

12. The method for preparing a solar cell according to any one of claims 9 to 11, wherein: In the step of placing a ferroelectric precursor solution on the surface of the perovskite layer and forming the ferroelectric layer after heat treatment, the heat treatment temperature is 80° C. to 120° C. and the time is 2 min to 10 min.

13. An electrical device, characterized in that: A solar cell comprising the solar cell according to any one of claims 1 to 6; or a solar cell manufactured by the method according to any one of claims 7 to 12.

14. A power generation device, characterized in that: A solar cell comprising the solar cell according to any one of claims 1 to 6; or a solar cell manufactured by the method according to any one of claims 7 to 12.

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