Perovskite solar cell and preparation method and application thereof

Abstract

The invention discloses a perovskite solar cell and a preparation method thereof, a laminated solar cell, a cell module and an electric device. The perovskite solar cell comprises a perovskite active layer, and the perovskite active layer comprises a perovskite structure substance and alkali metal fluorate. The perovskite active layer in the perovskite solar cell is doped with alkali metal fluorate, so that directional growth of perovskite grains can be effectively promoted, grain boundary defects of the perovskite active layer are reduced, bulk phase defects are passivated, non-radiative recombination of the perovskite active layer is reduced, and the photoelectric conversion efficiency of the perovskite solar cell is obviously improved. And moreover, a lattice structure can be effectively strengthened, material decomposition is inhibited, lattice vacancies are filled, external erosion is blocked, and ion migration is inhibited, so that the long-term stability of the perovskite solar cell is obviously improved. The laminated solar cell, the cell assembly and the electric device all comprise perovskite solar cells.

Description

Technical Field

[0001] This application belongs to the field of solar cell technology, specifically relating to a perovskite solar cell and its preparation method, a tandem solar cell, a battery module, and an electrical device. Background Technology

[0002] Metal halide perovskite solar cells (PSCs) are a revolutionary technology, demonstrating enormous development potential and application prospects due to their low cost, mature processes, high mechanical flexibility, and high photoelectric conversion efficiency (PCE). In particular, by constructing perovskite / silicon tandem solar cells, it is hoped that the Shockley-Queisser theoretical efficiency limit of single-junction solar cells can be broken at a relatively low cost, exhibiting even higher performance.

[0003] Despite the promising prospects of perovskite lattices (PSCs), their commercialization process still faces challenges such as efficiency losses due to varying perovskite grain sizes, inter-crystal compression, and dense grain boundaries within the perovskite active layer. Furthermore, they also face the problem of long-term stability degradation caused by the migration of ions (such as iodide and carboxymethyl ammonium ions) within the perovskite lattice of the active layer. Summary of the Invention

[0004] In view of the above problems, this application provides a perovskite solar cell and its preparation method, as well as a tandem solar cell containing perovskite solar cells, a cell module, and an electrical device, to solve the technical problems of efficiency loss and long-term stability degradation in existing perovskite solar cells.

[0005] In a first aspect, embodiments of this application provide a perovskite solar cell. The perovskite solar cell of this application embodiment includes a perovskite active layer, which comprises a perovskite structural material and an alkali metal fluoride salt.

[0006] Compared to existing perovskite solar cells, the perovskite active layer of the perovskite solar cell in this application embodiment significantly improves the photoelectric conversion efficiency by doping with alkali metal fluoroates. Specifically, the alkali metal cations in the alkali metal fluoroates act as crystal growth regulators, promoting larger and more uniform directional growth of perovskite grains, effectively reducing the number of grain boundaries and defect density. At the same time, the fluoroates can form stable coordination structures with point defects such as lead vacancies and iodine vacancies in the perovskite, significantly passivating bulk defects and reducing non-radiative recombination, thereby significantly improving the photoelectric conversion efficiency of the perovskite solar cell.

[0007] Furthermore, this doping strategy significantly enhances the long-term stability of the battery. Specifically, the highly electronegative Fo in the fluoroacid anions of alkali metal fluoroacids... - With Pb in the crystal lattice2+ Strong coordination bonds are formed, enhancing the lattice binding energy and inhibiting the decomposition of perovskite under humid, hot, and light conditions. Alkali metal cations fill lattice vacancies, making the structure more compact. This reduces ion migration channels, inhibits ion migration, and constructs an effective physical barrier to prevent water and oxygen erosion, thereby significantly improving the long-term stability of perovskite solar cells and delaying the degradation of their performance.

[0008] Furthermore, the alkali metal fluoroacid salt has a mass content of 0.01% to 0.1% in the perovskite active layer.

[0009] Furthermore, the alkali metal contained in the alkali metal fluoroacid salt includes any one of sodium, potassium, cesium, and rubidium.

[0010] Furthermore, the fluoroacid group contained in the alkali metal fluoroacid salt includes PF6. - BF4 - CF3SO3 - FSI - ([N(SO2F)2] - Any one of them.

[0011] Furthermore, the alkali metal fluorophosphate includes at least one of sodium tetrafluoroborate, potassium tetrafluoroborate, cesium tetrafluoroborate, rubidium tetrafluoroborate, potassium hexafluorophosphate, cesium hexafluorophosphate, and rubidium hexafluorophosphate.

[0012] Furthermore, the thickness of the perovskite active layer is 500 nm to 1500 nm.

[0013] Furthermore, the perovskite in the perovskite active layer includes MAPbI3, FAPbI3, CsPbI3, and FA. 0.8 MA 0.2 Pb(I 0.75 Br 0.2 5)3, FA 0.97 MA 0.03 Pb(I 0.97 Br 0.03 3. FA 0.92 MA 0.08 Pb(I 0.8 8Br 0.12 3. Cs 0.25 FA 0.75 Pb(I 0.8 Br 0.2 3. (FA) 0.95 Cs 0.05 ) 0.98 Pb(I 0.96 Br 0.04 3. Cs 0.25 FA 0.75 Pb0.5 Sn 0.5 I3, FA 0.83 MA 0.17 Cs 0.05 Pb(I 0.83 Br 0.17 At least one of the following 3.

[0014] Secondly, embodiments of this application provide a method for fabricating perovskite solar cells. The method for fabricating perovskite solar cells according to embodiments of this application includes the following steps: Alkali metal fluoroacid salts are mixed with perovskite precursor solutions to form a mixture solution; The mixture solution is applied to the surface of the electronic functional layer or the hole functional layer to form a film, thereby preparing a perovskite active layer.

[0015] The method for fabricating perovskite solar cells in this application involves mixing alkali metal fluorophosphates into the perovskite precursor solution. This results in the formation of an alkali metal fluorophosphate-doped perovskite active layer. During the formation of the active layer, the alkali metal fluorophosphates effectively promote the directional growth of perovskite grains, significantly reducing grain boundary defects compared to undoped perovskite active layers. Furthermore, they passivate bulk defects in the active layer and reduce non-radiative recombination, thereby significantly improving the photoelectric conversion efficiency of the perovskite solar cell. Simultaneously, the alkali metal fluorophosphates effectively strengthen the crystal structure of the perovskite material, inhibit its decomposition, fill lattice vacancies, block external erosion of the active layer, and suppress ion migration, thus significantly improving the long-term stability of the perovskite solar cell.

[0016] Furthermore, the mass concentration of the alkali metal fluoroacid salt in the mixed solution is 0.25 mg / ml to 1 mg / ml.

[0017] Furthermore, the alkali metal contained in the alkali metal fluoroacid salt includes any one of sodium, potassium, cesium, and rubidium.

[0018] Furthermore, the alkali metal fluorophosphate includes at least one of sodium tetrafluoroborate, potassium tetrafluoroborate, cesium tetrafluoroborate, rubidium tetrafluoroborate, potassium hexafluorophosphate, cesium hexafluorophosphate, and rubidium hexafluorophosphate.

[0019] Thirdly, embodiments of this application also provide a tandem solar cell. The tandem solar cell of this application includes a perovskite solar cell unit, which includes the perovskite solar cell of the above-described application embodiments or includes a perovskite solar cell prepared by the perovskite solar cell preparation method of the above-described application embodiments.

[0020] Since the tandem solar cells of this application embodiment include the perovskite solar cells of the above-described application embodiment, the tandem solar cells of this application embodiment have high photoelectric conversion efficiency, stable operating performance, and extended operating life.

[0021] Furthermore, the tandem solar cell is a perovskite / crystalline silicon tandem solar cell, with its top cell comprising the perovskite solar cell unit and its bottom cell comprising the crystalline silicon solar cell unit.

[0022] Fourthly, embodiments of this application also provide a battery module. The battery module of this application includes a perovskite solar cell of this application, a perovskite solar cell prepared according to the perovskite solar cell preparation method of this application, or a tandem solar cell of this application.

[0023] Because the battery module in this embodiment contains perovskite solar cells, the stability of the battery module's operating performance is improved, and its operating life is extended.

[0024] Fifthly, embodiments of this application also provide an electrical device. The electrical device of this application includes the perovskite solar cell, the tandem solar cell, or the battery module of this application. Because the electrical device of this application contains the perovskite solar cell, its reliability and lifespan are improved. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of a perovskite solar cell according to an embodiment of this application; Figure 2 This is a schematic diagram of a perovskite / crystalline silicon tandem solar cell according to an embodiment of this application.

[0027] The reference numerals in the detailed embodiments are as follows: 10-Perovskite solar cell, 11-Second electrode structure, 12-Hole transport layer, 13-Perovskite active layer, 14-Electron transport layer, 15-First electrode structure; 20-Crystal silicon solar cell. Detailed Implementation

[0028] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0029] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0030] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0031] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0032] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0033] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as µg, mg, g, or kg.

[0034] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0035] Faced with the global energy crisis and climate change challenges, developing efficient and low-cost renewable energy technologies has become an urgent priority. Photovoltaic technology, as a key solution, has long been dominated by silicon-based solar cells. However, in recent years, perovskite solar cells (PSCs), as a revolutionary technology, have demonstrated enormous development potential and application prospects due to their low cost, mature processes, high mechanical flexibility, and high photoelectric conversion efficiency (PCE). In particular, by constructing perovskite / silicon tandem solar cells, it is expected to break through the Shockley-Queisser theoretical efficiency limit of single-junction solar cells at a relatively low cost, showcasing a higher performance ceiling.

[0036] Despite the promising future of PSCs, their commercialization process still faces the following challenges: efficiency losses and insufficient long-term stability. In terms of efficiency, the perovskite light-absorbing layer in current high-performance photoelectric cells (PSCs) is mainly a polycrystalline thin film. The nucleation and crystallization processes of this film are randomly affected by various factors such as temperature, humidity, and solvent evaporation rate, making precise control difficult and resulting in poor film quality. Specifically, this manifests as inconsistent grain size, inter-crystal compression, and dense grain boundaries. These dense grain boundaries easily accumulate defects, becoming trap centers for non-radiative recombination of charge carriers (electrons and holes), causing severe carrier loss and limiting the open-circuit voltage and fill factor of the cell, thus hindering further improvements in photoelectric conversion efficiency. Furthermore, pinholes, cracks, and incompletely crystallized amorphous regions are easily generated during the fabrication process. These structural defects disrupt the continuity of the film and severely affect the longitudinal transport of charge.

[0037] In terms of stability, ion migration is considered one of the core factors causing performance degradation in PSCs. Under external stresses such as light, electric fields, and damp heat, ions (such as iodide ions and carboxymethyl ammonium ions) in the perovskite lattice migrate. This migration triggers a series of adverse reactions, including causing perovskite phase transformation, accelerating the decomposition of photosensitive materials, causing physical damage to interface and grain boundary structures, and generating severe current-voltage (JV) hysteresis. These effects work together to ultimately lead to a rapid and irreversible decline in device performance.

[0038] To address these challenges, existing technologies generally employ methods such as optimizing thin film fabrication processes and using interface engineering and passivation strategies for tentative improvements. However, in practical applications, it has been found that existing technologies primarily focus on post-processing or localized improvements to existing defects, failing to fundamentally solve the intrinsic problems of uneven grain size and high grain boundary defect density inherent in polycrystalline thin films during random nucleation and rapid crystallization; they also have limited effectiveness in suppressing ion migration. More importantly, existing technologies often struggle to simultaneously achieve both high-quality crystallization and enhanced intrinsic stability of perovskite thin films.

[0039] Therefore, in order to synergistically optimize the crystallization process of perovskite in PSCs, effectively passivate bulk phase and interface defects, and strongly suppress ion migration, thereby improving photoelectric conversion efficiency and significantly enhancing the long-term operational stability of the device, the embodiments of this application provide the following solutions.

[0040] [Perovskite Solar Cells] In a first aspect, embodiments of this application provide a perovskite solar cell. The perovskite solar cell of this application embodiment includes a perovskite active layer. Furthermore, the perovskite active layer comprises a perovskite structural material and an alkali metal fluoride salt.

[0041] In the perovskite solar cells of this application embodiment, the perovskite active layer contains alkali metal fluoride salts, which gives the perovskite solar cells at least the following technical effects: 1) Doping the perovskite active layer with alkali metal fluorides can effectively promote the directional growth of perovskite grains, reduce grain boundary defects in the perovskite active layer, passivate bulk defects, and reduce non-radiative recombination in the perovskite active layer, thereby significantly improving the photoelectric conversion efficiency of perovskite solar cells. Promoting directional grain growth and reducing grain boundary defects: The alkali metal cations contained in alkali metal fluoroacids can act as "seeds" or "regulators" for crystal growth, guiding perovskite grains to grow larger and more uniformly. This effectively reduces the number of grain boundaries, thereby directly reducing the defect state density introduced by grain boundaries and decreasing carrier recombination at grain boundaries.

[0042] Passivating bulk defects and reducing nonradiative recombination: The fluoroanions in alkali metal fluoroates can combine with key defects such as lead vacancies and iodine vacancies in the perovskite active layer to form stable coordination structures. This process can significantly passivate these defects, preventing them from acting as nonradiative recombination centers for charge carriers, thereby greatly reducing the loss of photogenerated charge carriers and contributing to obtaining higher open-circuit voltage and fill factor.

[0043] 2) Doping the perovskite active layer with alkali metal fluorides can effectively strengthen the crystal structure, inhibit material decomposition, and simultaneously fill lattice vacancies, blocking external erosion and inhibiting ion migration, thereby significantly improving the long-term stability of perovskite solar cells. Strengthening the crystal structure and inhibiting material decomposition: The F in the fluoroacid anions of alkali metal fluoroacids - It has extremely high electronegativity and can react with Pb in the perovskite lattice. 2+ This forms strong and stable coordination bonds. This enhances the overall binding energy of the crystal lattice and effectively suppresses the decomposition of perovskite structure materials under stress conditions such as humidity and light (e.g., suppressing the precipitation of harmful PbI2), thus fundamentally improving the environmental stability of the perovskite active layer.

[0044] Filling lattice vacancies and blocking external erosion: Alkali metal cations can fill the existing vacancies in the perovskite lattice, making the crystal structure more compact. This "interstitial filling" effect not only reduces the channels for ion migration but also constructs a physical barrier, which can more effectively resist the penetration and erosion of external water vapor and oxygen, thus delaying the performance degradation of perovskite solar cells.

[0045] Suppressing ion migration: Doped alkali metal fluorides can "anchor" easily migratable iodide ions (I- ions) in perovskite structures by occupying interstitial or defect sites in the lattice. - This slows down the migration rate, thereby reducing the hysteresis effect of perovskite solar cells and extending their operating life.

[0046] Therefore, the perovskite solar cells of this application, by doping the perovskite active layer with alkali metal fluorides, can simultaneously improve the photoelectric conversion efficiency and long-term stability of perovskite solar cells.

[0047] In some embodiments, the mass content of alkali metal fluorophosphates doped in the perovskite active layer of the above-mentioned perovskite solar cell is 0.01% to 0.1%. In exemplary cases, this can be a typical but non-limiting content such as 0.01%, 0.02%, 0.05%, 0.06%, 0.08%, or 0.1%, or a range between any two content values. Having alkali metal fluorophosphates in the perovskite active layer within this doping range can further enhance the directional growth of perovskite grains, reduce grain boundary defects in the perovskite active layer, passivate bulk defects, and reduce non-radiative recombination in the perovskite active layer, thereby further improving the photoelectric conversion efficiency of the perovskite solar cell. Simultaneously, it can further effectively strengthen the crystal structure, inhibit material decomposition, fill lattice vacancies, block external erosion, and inhibit ion migration, thereby further improving the operational stability of the perovskite solar cell.

[0048] In some embodiments, the alkali metal element contained in the alkali metal fluoroacids doped in the perovskite active layer includes any one of sodium, potassium, cesium, and rubidium. These types of alkali metal cations can more effectively act as "seeds" or "regulators" for crystal growth, guiding the perovskite grains to grow larger and more uniformly, thereby further reducing the defect state density of the perovskite active layer and assisting fluoroacid ions in suppressing ion migration. Furthermore, these types of alkali metal cations can effectively fill lattice vacancies, improving the density of the perovskite crystal structure, thus more effectively resisting the penetration and erosion of external moisture and oxygen, and enhancing the stability of the perovskite active layer.

[0049] In some embodiments, the fluoroacids contained in the alkali metal fluoroacids doped in the perovskite active layer include PF6. - BF4 - CF3SO3 - FSI - ([N(SO2F)2] - Any one of the following: fluoroacids. These types of fluoroacids can enhance their binding with key defects such as lead vacancies and iodine vacancies in the perovskite active layer, improving the stability of the coordination structure and thus further passivating these defects, thereby increasing the open-circuit voltage and fill factor of perovskite solar cells. Furthermore, these types of fluoroacids are rich in F... - These ions effectively enhance the electronegativity of the fluoroates, thereby increasing the interaction between the fluoroates and Pb in the perovskite lattice. 2+ This enhances the stability of coordination bonds and inhibits ion migration, thereby further improving the environmental stability of the perovskite active layer.

[0050] In some embodiments, the alkali metal fluorophosphates doped in the perovskite active layer include at least one of sodium tetrafluoroborate (NaBF4), potassium tetrafluoroborate (KBF4), cesium tetrafluoroborate (CsBF4), rubidium tetrafluoroborate (RbBF4), potassium hexafluorophosphate (KPF6), cesium hexafluorophosphate (CsPF6), rubidium hexafluorophosphate (RbPF6), potassium trifluoromethanesulfonate (KCF3SO3), cesium trifluoromethanesulfonate (CsCF3SO3), rubidium trifluoromethanesulfonate (RbCF3SO3), sodium trifluoromethanesulfonate (NaCF3SO3), potassium bis(fluorosulfonyl)imide (KFSI), cesium bis(fluorosulfonyl)imide (CsFSI), and rubidium bis(fluorosulfonyl)imide (RbFSI). These types of alkali metal fluoroacids contain both alkali metal cations and fluoroacid ions, which can enhance the effects of alkali metal fluoroacids as described above. This can further reduce grain boundary defects and passivation bulk defects in the perovskite active layer, thereby improving the photoelectric conversion efficiency of perovskite solar cells. At the same time, they can effectively strengthen the crystal structure, inhibit ion migration, improve the stability of perovskite structure materials, and improve the filling of lattice vacancies, blocking external erosion, thus improving the working stability of perovskite solar cells.

[0051] In some embodiments, the thickness of the perovskite active layer in the above-described perovskite solar cell can be 500 nm to 1500 nm. In exemplary cases, it can be a typical but non-limiting thickness such as 500 nm, 800 nm, 1000 nm, 1200 nm, or 1500 nm, or any range between two thickness values. Perovskite active layers with this thickness range, when doped with alkali metal fluorides, exhibit relatively few grain boundary defects, low non-radiative recombination, strengthened lattice structure, increased filling of lattice vacancies, and suppressed ion migration, thereby further improving photoelectric conversion efficiency while also achieving efficient charge collection.

[0052] In some embodiments, the perovskite structure material contained in the perovskite active layer of the perovskite solar cell may include ABX3; wherein, A in ABX3 is a monovalent cation, including but not limited to at least one of cesium (Cs), rubidium (Rb), methylamino (CH3NH3), and formamidinyl (CH2(NH2)2); B is a divalent cation, including but not limited to at least one of lead (Pb), copper (Cu), zinc (Zn), gallium (Ga), tin (Sn), and calcium (Ca); and X is a monovalent anion, including but not limited to at least one of iodine (I), bromine (Br), chloride (Cl), fluorine (F), and thiocyanate (SCN).

[0053] In the embodiments, when the perovskite structural material includes ABX3, the ABX3 may include MAPbI3, FAPbI3, CsPbI3, FA 0.8 MA 0.2Pb(I 0.75 Br 0.25 3. FA 0.97 MA 0.03 Pb(I 0.97 Br 0.03 3. FA 0.92 MA 0.08 Pb(I 0.88 Br 0.12 3. Cs 0.25 FA 0.75 Pb(I 0.8 Br 0.2 3. (FA) 0.95 Cs 0.05 ) 0.98 Pb(I 0.96 Br 0.04 3. Cs 0.25 FA 0.75 Pb 0.5 Sn 0.5 I3, FA 0.83 MA 0.17 Cs 0.05 Pb(I 0.83 Br 0.17 At least one of the following 3.

[0054] The aforementioned types of perovskite structures, when doped with alkali metal fluorides, can improve the photoelectric conversion efficiency and activity stability of the perovskite active layer, reduce ion migration, and improve film quality.

[0055] In the perovskite solar cells of the above embodiments, in addition to the perovskite active layer of the above embodiments, the perovskite solar cell also includes an electron transport functional layer, a hole transport functional layer, and an electrode structure. The electron transport functional layer is disposed on one side of the perovskite active layer and may include an electron transport layer, and may further include functional layer structures such as a hole blocking layer. The hole transport functional layer is disposed on the side of the perovskite active layer opposite to the electron transport functional layer and may include a hole transport layer, and may further include functional layer structures such as an electron blocking layer. The electrode structure is disposed on the side of the electron transport functional layer away from the perovskite active layer and on the side of the hole transport functional layer away from the perovskite active layer.

[0056] As in the embodiments, the structure of the perovskite solar cells in the above embodiments can be as follows: Figure 1As shown, the perovskite solar cell 10 includes a second electrode structure 11, a hole transport layer 12, a perovskite active layer 13, an electron transport layer 14, and a first electrode structure 15. These components are sequentially stacked along the direction from the second electrode structure 11 to the first electrode structure 15. The perovskite active layer 13 is the perovskite active layer described above, meaning it is doped with an alkali metal fluoride salt.

[0057] In the embodiments, in such Figure 1 The perovskite solar cell shown may include a first electrode structure 15 comprising a first transparent conductive layer and a first transparent electrode. The first transparent conductive layer and the first transparent electrode may be made of appropriate conductive materials and their thicknesses may be adjusted according to actual production needs.

[0058] In the embodiments, in such Figure 1 In the perovskite solar cell shown, the electron transport layer 14 may include a first electron transport layer and a second electron transport layer. The first and second electron transport layers are stacked sequentially along the direction away from the perovskite active layer 13. The first electron transport layer may be stacked with the perovskite active layer 13. The first electron transport layer may include a fullerene (C60); the second electron transport layer may include tin oxide (SnO2). By configuring the electron transport layer 14 into a composite structure comprising a C60-containing first electron transport layer and a SnO2-containing second electron transport layer, the first and second electron transport layers, together with the perovskite active layer 13, form a stepped energy level structure. This structure enables energy level synergistic matching and stepped electron extraction, significantly promoting electron extraction and injection; simultaneously, it suppresses electron-hole recombination at the interface, improving interface passivation.

[0059] In the embodiments, when as Figure 1 When the electron transport layer 14 shown includes the first electron transport layer and the second electron transport layer, the material of the first electron transport layer can be C60, and it may also contain other electron transport materials or additives, including but not limited to passivating agents. Furthermore, the thickness of the first electron transport layer can be flexibly adjusted according to actual production needs. The material of the second electron transport layer can be tin oxide, and it may also contain other electron transport materials or additives, specifically selected according to actual production needs. Furthermore, the thickness of the second electron transport layer can be flexibly adjusted according to actual production needs. Of course, the electron transport layer 14 can also be a single layer structure.

[0060] In the embodiments, in such Figure 1In the perovskite solar cell shown, the hole transport layer 12 can be made of appropriate film material and its thickness can be adjusted according to the actual production needs. The material of the hole transport layer 12 may include at least one of [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz) or [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz).

[0061] In the embodiments, in such Figure 1 The perovskite solar cell shown may include a second electrode structure 11, which may comprise a second transparent conductive layer and a second transparent electrode. The second transparent conductive layer and the second transparent electrode may be made of appropriate conductive materials and their thicknesses may be adjusted according to actual production needs.

[0062] In addition, the perovskite solar cells in the above embodiments can be either a formal structure or an inverted structure.

[0063] [Preparation methods for perovskite solar cells] Secondly, the embodiments of this application improve the fabrication method of the perovskite solar cell described in the embodiments of the above application. In some embodiments, combined with Figure 1 The method for fabricating perovskite solar cells according to embodiments of this application includes the following steps: S10: Alkali metal fluoroacid salts are mixed with perovskite precursor solution to form a mixed solution; S20: The mixture solution is applied to the surface of the electronic functional layer or the hole functional layer to form a film, thereby preparing a perovskite active layer.

[0064] The method for fabricating perovskite solar cells in this application involves mixing alkali metal fluorophosphates into the perovskite precursor solution, resulting in an alkali metal fluorophosphate-doped perovskite active layer. During the formation of the perovskite active layer, the alkali metal fluorophosphates effectively promote the directional growth of perovskite grains, significantly reducing grain boundary defects compared to undoped perovskite active layers. They also passivate bulk defects in the perovskite active layer, reducing non-radiative recombination and thus significantly improving the photoelectric conversion efficiency of the perovskite solar cell. Simultaneously, the alkali metal fluorophosphates effectively strengthen the crystal structure of the perovskite material, inhibit its decomposition, fill lattice vacancies, block external erosion of the perovskite active layer, and suppress ion migration, thereby significantly improving the long-term stability of the perovskite solar cell.

[0065] Step S10: The alkali metal fluoroacid salt in step S10 is the alkali metal fluoroacid salt contained in the perovskite active layer of the perovskite solar cell in the embodiments of the above application. Therefore, the type of this alkali metal fluoroacid salt is as described above. For example, in some embodiments, the alkali metal element contained in the alkali metal fluoroacid salt doped in the perovskite active layer includes any one of sodium, potassium, cesium, and rubidium. For example, in some embodiments, the fluoroacid ion contained in the alkali metal fluoroacid salt includes PF6. - BF4 - CF3SO3 - FSI - ([N(SO2F)2] - Any one of the following. In some embodiments, the alkali metal fluorophosphate doped in the perovskite active layer includes at least one of sodium tetrafluoroborate (NaBF4), potassium tetrafluoroborate (KBF4), cesium tetrafluoroborate (CsBF4), rubidium tetrafluoroborate (RbBF4), potassium hexafluorophosphate (KPF6), cesium hexafluorophosphate (CsPF6), rubidium hexafluorophosphate (RbPF6), potassium trifluoromethanesulfonate (KCF3SO3), cesium trifluoromethanesulfonate (CsCF3SO3), rubidium trifluoromethanesulfonate (RbCF3SO3), sodium trifluoromethanesulfonate (NaCF3SO3), potassium bis(fluorosulfonyl)imide (KFSI), cesium bis(fluorosulfonyl)imide (CsFSI), and rubidium bis(fluorosulfonyl)imide (RbFSI).

[0066] In some embodiments, during the mixing process of alkali metal fluoroacid salt and perovskite precursor solution, the amount of alkali metal fluoroacid salt added can meet the mass content of alkali metal fluoroacid salt in the perovskite active layer of the perovskite solar cell in the above-described embodiments. For example, by controlling the amount of alkali metal fluoroacid salt added, the mass content of alkali metal fluoroacid salt in the formed perovskite active layer is 0.01% to 0.1%.

[0067] In order to adjust the doping amount of alkali metal fluoroacid salt in the formation of the perovskite active layer, in some embodiments, the mass concentration of the alkali metal fluoroacid salt in the mixed solution prepared in step S10 is 0.25 mg / ml to 1 mg / ml. In exemplary examples, it can be a typical but non-limiting concentration such as 0.25 mg / ml, 0.5 mg / ml, 0.75 mg / ml, 1 mg / ml, or any range between two concentration values.

[0068] Alternatively, the perovskite precursor solution in step S10 can be the precursor solution of the perovskite structural material in the perovskite active layer of the perovskite solar cell in the above-described embodiments.

[0069] Step S20: The method for forming a film on the surface of the electronic functional layer or hole functional layer using the mixed solution prepared in step S10 in step S20 can be a conventional method for forming a perovskite active layer, or a method improved based on a conventional method. As long as the mixed solution prepared in step S10 forms a perovskite active layer, it is within the scope of the embodiments disclosed in this application.

[0070] In addition, depending on the structure of the prepared perovskite solar cell, film formation can be performed on the surface of the electronic functional layer or the hole functional layer. For example, when the prepared perovskite solar cell has a formal structure, a perovskite active layer can be formed on the surface of the electronic functional layer. The electronic functional layer can be the same as the electronic functional layer in the perovskite solar cell described in the above-mentioned application embodiments, such as including an electron transport layer or further including a hole blocking layer. When the prepared perovskite solar cell has an inverted structure, a perovskite active layer can be formed on the surface of the hole functional layer. The hole functional layer can be the same as the hole functional layer in the perovskite solar cell described in the above-mentioned application embodiments, such as including a hole transport layer or further including an electron blocking layer.

[0071] Of course, depending on the structure of the perovskite solar cell, the fabrication of functional layers such as electron functional layer, hole functional layer and electrode structure is also required. Simply fabricate each functional layer in sequence according to the structure of the perovskite solar cell.

[0072] [Taped Solar Cells] Thirdly, embodiments of this application also provide a tandem solar cell. The tandem solar cell of this application includes a perovskite solar cell unit, which includes the perovskite solar cell described in the above-described embodiments or includes a perovskite solar cell prepared by the perovskite solar cell preparation method described above.

[0073] Since the tandem solar cells of this application embodiment include the perovskite solar cells of the above-described application embodiment, the tandem solar cells of this application embodiment have high photoelectric conversion efficiency, stable operating performance, and extended operating life.

[0074] In some embodiments, the perovskite solar cell mentioned above is included in the tandem solar cell of the present application embodiments as the top cell, and the bottom cell of the tandem solar cell of the present application embodiments may include one of the following: crystalline silicon cell, perovskite cell, copper indium gallium selenide cell, and organic photovoltaic cell.

[0075] In the embodiments, when the bottom cell of the tandem solar cell in this application embodiment includes a crystalline silicon cell, the tandem solar cell in this application embodiment belongs to a perovskite / crystalline silicon tandem solar cell. At this time, the structure of the perovskite / crystalline silicon tandem solar cell is as follows: Figure 2As shown, its top cell includes a perovskite solar cell unit, namely the perovskite solar cell 10 of the above-described embodiment, and its bottom cell includes a crystalline silicon solar cell unit 20. The crystalline silicon solar cell unit 20 can be a conventional crystalline silicon solar cell structure.

[0076] In the embodiments, in such Figure 2 In the perovskite / crystalline silicon tandem solar cell shown, crystalline silicon solar cell units 20 are stacked on one side near the hole transport layer 12 of the perovskite solar cell 10. In this case, the first electrode structure 15 of the perovskite solar cell 10 serves as the front electrode surface or the illumination surface. Thus, sunlight first incident on the surface of the first electrode structure 15 (i.e., the front electrode surface) of the perovskite solar cell 10 (which acts as the top cell), then passes sequentially through the first electrode structure 15, the electron transport layer 14, and the perovskite active layer 13. Photons with energy higher than the perovskite bandgap are absorbed, exciting electron-hole pairs; while low-energy, long-wavelength photons pass through the perovskite active layer 13. These transmitted photons then pass through the intermediate tunnel recombination junction and are effectively absorbed and converted by the crystalline silicon solar cell unit 20 (which acts as the bottom cell). Through this top-bottom division of labor and spectral matching design, the tandem solar cell maximizes the utilization of the solar spectrum, achieving a higher theoretical photoelectric conversion efficiency than a single-junction cell.

[0077] In the embodiments, in such Figure 2 In the perovskite / crystalline silicon tandem solar cell shown, the contact interface between the perovskite solar cell 10 and the crystalline silicon solar cell unit 20 has a textured structure, such as a pyramidal textured structure. The relevant functional layers of the perovskite solar cell 10 are disposed on this textured structure, such as… Figure 1 The second electrode structure 11 shown constitutes a three-dimensional interlocking structure. This three-dimensional interlocking structure can provide an anchoring effect, enhance interfacial adhesion, and effectively resist interlayer shear. At the same time, it increases the actual contact area between battery cells, allowing thermal stress and internal stress at the interface to be fully dispersed, avoiding film cracking or delamination caused by stress concentration, thereby improving the long-term operational reliability of tandem solar cells.

[0078] [Battery Components] Fourthly, embodiments of this application also provide a battery module. The battery module includes the perovskite solar cell of the above-described embodiments, or includes a perovskite solar cell prepared by the preparation method of the perovskite solar cell of the above-described embodiments, or includes a tandem solar cell of the present application embodiments. Therefore, the stability of the operating performance of the battery module of the present application embodiments is improved, and its operating life is extended.

[0079] [Electrical appliances] Fifthly, embodiments of this application also provide an electrical device. The electrical device of this application includes a power supply unit, and may also include other auxiliary or necessary components. The power supply unit contains a perovskite solar cell, a tandem solar cell, or a battery module as described in the above embodiments, used to provide electrical energy. Therefore, the reliability and lifespan of the electrical device of this application are improved.

[0080] In some embodiments, the power supply may include at least one of a rechargeable power source, a solar-powered electronic device, a solar-powered drone, etc.

[0081] [Example] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0082] Example 1: This embodiment provides a perovskite solar cell, the structure of which is as follows: Figure 1 As shown, the perovskite solar cell 10 includes a transparent first electrode structure 15, an electron transport layer 14, a perovskite active layer 13, a hole transport layer 12, and a second electrode structure 11, which are stacked sequentially along the direction of sunlight. The first electrode structure 15 consists of a first transparent electrode and a first transparent conductive layer, the hole functional layer 12 is a hole transport layer, and the second electrode 11 is an ITO second transparent conductive layer.

[0083] The fabrication method of perovskite solar cells includes the following steps: S1: Sputter an ITO intermediate layer on the substrate to form the second transparent conductive layer in the second electrode 11; S2: A 3 nm thick SAM hole transport layer 12 was prepared on the surface of the ITO layer using a one-step spin coating method. The material of the SAM hole transport layer was 2PABCZ ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid). S3: Mix 0.5 mg of sodium tetrafluoroborate (NaBF4) with 1 ml of 1.5 M component FA in a specific ratio. 0.97 MA 0.03 Pb(I 0.97 Br 0.03 The precursor solutions were mixed evenly to form a homogeneous mixture solution; a perovskite active layer 13 with a thickness of 600 nm was prepared on the surface of the treated SAM hole transport layer using a coating method; wherein, the mass content of sodium tetrafluoroborate in the perovskite active layer 13 was 0.048%; S4: A first electron transport layer with a thickness of 15 nm and made of C60 is prepared on the surface of the perovskite active layer 13 by thermal evaporation. Then, a second electron transport layer with a thickness of 12 nm and made of SnO2 is prepared on the surface of the first electron transport layer by thermal evaporation. The first electron transport layer and the second electron transport layer constitute the electron transport layer 14. S5: A first transparent conductive layer with a thickness of 30 nm and made of indium zinc oxide (IZO) is prepared on the surface of the second electron transport layer by magnetron sputtering; a metal grid line (first transparent electrode) with a thickness of 400 nm and made of Ag is prepared on the surface of the first transparent conductive layer by thermal evaporation; the first transparent conductive layer and the metal grid line together form the first electrode structure 15, thereby obtaining a perovskite solar cell.

[0084] Examples 2 to 6: Examples 2 through 6 each provide a perovskite solar cell. Compared to the perovskite solar cell in Example 1, the alkali metal fluorophosphate doped in the perovskite active layer of Example 2 is CsBF4, the alkali metal fluorophosphate doped in the perovskite active layer of Example 3 is KPF6, the alkali metal fluorophosphate doped in the perovskite active layer of Example 4 is RbPF6, the alkali metal fluorophosphate doped in the perovskite active layer of Example 5 is CsCF3SO3, and the alkali metal fluorophosphate doped in the perovskite active layer of Example 6 is CsFSI. Everything else is the same as in Example 1.

[0085] Examples 7 to 9: Examples 7 to 9 each provide a perovskite solar cell. Compared with the perovskite solar cell in Example 1, the doping mass content of NaBF4 alkali metal fluoroacid salt in the perovskite active layer of Examples 7 to 9 is shown in Table 1 below. The other contents are the same as in Example 1.

[0086] Example 10: This embodiment provides a perovskite / silicon-based tandem solar cell and its fabrication method. The perovskite / silicon-based tandem solar cell includes a perovskite solar cell as the top cell and a crystalline silicon cell as the bottom cell. The perovskite solar cell as the top cell includes a transparent Ag layer top electrode, a SnO2 hole-blocking layer, a C60 electron transport layer, and a rubidium tetrafluoroborate RbBF4-doped Cs electrode, sequentially stacked along the sunlight path. 0.05 MA 0.15 FA 0.8 Pb(I 0.75 Br 0.25)3. Perovskite active layer, NiOx hole transport layer and ITO transparent conductive layer; Crystalline silicon cell 20 includes: Light-receiving surface (the surface opposite to the top cell): has a textured pyramid structure, and an n-type amorphous silicon layer is sequentially disposed thereon as the front surface field and front contact, which contacts the ITO transparent conductive layer of the perovskite solar cell; Back-lighting surface: a p-type amorphous silicon layer and an ITO transparent conductive oxide layer are sequentially disposed thereon to form a back surface field; Finally, a metal grid electrode is formed on the transparent conductive oxide layer of the back-lighting surface as the back electrode of the bottom cell.

[0087] The fabrication method of perovskite / silicon-based tandem solar cells includes the following steps: S1: Fabrication of a crystalline silicon bottom cell as the bottom cell: The N-type silicon wafer is polished with a texture height of 500~1000nm; the front intrinsic amorphous silicon, n-type amorphous silicon with a thickness of 25nm, and the back intrinsic amorphous silicon, p-type amorphous silicon with a total thickness of 20nm are prepared by PECVD; the bottom electrode, made of transparent conductive oxide ITO with a thickness of 110nm, is prepared on the p-silicon surface by sputtering. S2: A tunneling layer with a thickness of 50 nm made of transparent conductive oxide ITO was prepared on the front n-silicon surface by sputtering. S3: A hole transport layer with a thickness of 15 nm and made of NiOx was prepared by sputtering. S4: Mix 1 mg of rubidium tetrafluoroborate (RbBF4) with 1 ml of 1.7 M component Cs in a specific ratio. 0.05 MA 0.15 FA 0.8 Pb(I 0.75 Br 0.25 The precursor solutions of 3 were mixed evenly to form a homogeneous mixture solution; a perovskite active layer with a thickness of 1200 nm was prepared on the surface of the treated NiOx hole transport layer by coating method. S5: An electron transport layer with a C60 material and a thickness of 12nm was prepared by thermal evaporation. S6: A hole-blocking layer with a thickness of 15 nm and made of SnO2 was prepared by atomic deposition. S7: A top electrode with a thickness of 200nm made of Ag is deposited on the surface of the hole blocking layer by thermal evaporation.

[0088] Comparative Example 1: This comparative example provides a perovskite solar cell. Compared to the perovskite solar cell in Example 1, the perovskite active layer in Comparative Example 1 does not contain NaBF4 alkali metal fluoride. Everything else is the same as in Example 1.

[0089] Comparative Example 2: This comparative example provides a perovskite / silicon-based tandem solar cell. Compared to the perovskite solar cell in Example 10, the perovskite active layer in Comparative Example 2 does not contain RbBF4 alkali metal fluoride. Everything else is the same as in Example 1.

[0090] Parameter determination and performance testing of perovskite solar cells: The parameters and performance of the perovskite solar cells in Examples 1 to 10 and Comparative Examples 1 to 2 were measured as shown in Table 1 below. The detection methods for each performance are as follows, and the test results are shown in Table 1 below.

[0091] Test methods for perovskite solar cell photoelectric efficiency, photoelectric efficiency change after MPP (maximum power point) tracking (ΔPCE), and ΔPCE after aging: Under standard test conditions (AM 1.5G, 100 mW / cm², 25°C), the current density-voltage curve is measured using a solar simulator and a source meter (such as Keithley 2400), and the initial efficiency (PCE_initial) and the efficiency after aging (PCE_aged) are directly read; the change value (ΔPCE) = PCE_aged - PCE_initial.

[0092] MPP-T test method: Under an ambient temperature of 45°C and a solar radiation intensity, the perovskite solar cell was continuously subjected to maximum power point tracking for 10 min to monitor and evaluate the degradation of its output power in real time, and then the photoelectric efficiency was measured again.

[0093] Aging process: Each perovskite solar cell was subjected to an aging test in a nitrogen atmosphere at 85°C for 1000 hours, and then the photoelectric efficiency (PCE_aged) was measured again.

[0094] Open-circuit voltage test method for perovskite solar cells: Same as above, directly read the initial open-circuit voltage (VOC) from the JV curve. Short-circuit current testing method for perovskite solar cells: The initial short-circuit current density (JSC) is directly read from the JV curve.

[0095] The fill factor (FF) of perovskite solar cells is calculated from the JV curve (FF = Pmax / (VOC × JSC)).

[0096] Table 1

[0097] Table 1 shows that, by comparing Examples 1 to 6 with Comparative Example 1 and Comparative Example 10 with Comparative Example 2, the alkali metal fluorophosphates doped in the perovskite active layer can effectively improve the electrical properties of perovskite solar cells, including photoelectric efficiency. In particular, they can significantly improve the photoelectric conversion efficiency, enhance the working stability of perovskite solar cells, and extend their working life.

[0098] Comparing Examples 1 and 7 to 9, it can be seen that the mass content of alkali metal fluorophosphates doped in the perovskite active layer affects the relevant electrical performance of perovskite solar cells. For example, when the amount of NaBF4 introduced increases in the range of 0.024% to 0.096%, the device performance shows a trend of first increasing and then decreasing.

[0099] Therefore, as shown in Table 1 and the comparative analysis above, doping the perovskite active layer of a perovskite solar cell with alkali metal fluorophosphates effectively promotes the directional growth of perovskite grains, improves grain uniformity, and significantly reduces grain boundary defects in the formed perovskite active layer compared to the undoped layer. It also passivates bulk defects in the perovskite active layer, reduces non-radiative recombination, and thus significantly improves the photoelectric conversion efficiency of the perovskite solar cell. Simultaneously, alkali metal fluorophosphates effectively strengthen the lattice structure of the perovskite material, inhibit its decomposition, fill lattice vacancies, block external erosion of the perovskite active layer, and inhibit ion migration, thereby significantly improving the long-term stability of the perovskite solar cell and extending its operating life.

[0100] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A perovskite solar cell, comprising a perovskite active layer, characterized in that: The perovskite active layer comprises perovskite structural material and alkali metal fluoride salts.

2. The perovskite solar cell as described in claim 1, characterized in that: The alkali metal fluoroacid salt has a mass content of 0.01% to 0.1% in the perovskite active layer.

3. The perovskite solar cell as described in claim 1 or 2, characterized in that: The alkali metal fluoroacid salt contains any one of sodium, potassium, cesium, and rubidium. And / or, the fluoroacid group contained in the alkali metal fluoroacid salt includes PF6. - BF4 - CF3SO3 - FSI - ([N(SO2F)2] - Any one of them.

4. The perovskite solar cell according to claim 1 or 2, characterized in that: The alkali metal fluoroacid salts include at least one of sodium tetrafluoroborate, potassium tetrafluoroborate, cesium tetrafluoroborate, rubidium tetrafluoroborate, potassium hexafluorophosphate, cesium hexafluorophosphate, rubidium hexafluorophosphate, potassium trifluoromethanesulfonate, cesium trifluoromethanesulfonate, rubidium trifluoromethanesulfonate, sodium trifluoromethanesulfonate, potassium bis(fluorosulfonyl)imide, cesium bis(fluorosulfonyl)imide, and rubidium bis(fluorosulfonyl)imide.

5. The perovskite solar cell as described in claim 1 or 2, characterized in that: The thickness of the perovskite active layer is 500 nm to 1500 nm.

6. The perovskite solar cell according to claim 1 or 2, characterized in that: The perovskite in the perovskite active layer includes ABX3; wherein, A in ABX3 is a monovalent cation, including but not limited to at least one of cesium (Cs), rubidium (Rb), methylamino (CH3NH3), and formamidinyl (CH2(NH2)2); B is a divalent cation, including but not limited to at least one of lead (Pb), copper (Cu), zinc (Zn), gallium (Ga), tin (Sn), and calcium (Ca); and X is a monovalent anion, including but not limited to at least one of iodine (I), bromine (Br), chloride (Cl), fluorine (F), and thiocyanate (SCN).

7. A method for fabricating a perovskite solar cell, characterized in that, Includes the following steps: Alkali metal fluoroacid salts are mixed with perovskite precursor solutions to form a mixture solution; The mixture solution is applied to the surface of the electronic functional layer or the hole functional layer to form a film, thereby preparing a perovskite active layer.

8. The preparation method according to claim 7, characterized in that: The alkali metal fluoroacid salt has a mass concentration of 0.25 mg / ml to 1 mg / ml in the mixture solution; And / or, the alkali metal contained in the alkali metal fluoroacid salt includes any one of sodium, potassium, cesium, and rubidium. And / or, the alkali metal fluorophosphate includes at least one of sodium tetrafluoroborate, potassium tetrafluoroborate, cesium tetrafluoroborate, rubidium tetrafluoroborate, potassium hexafluorophosphate, cesium hexafluorophosphate, and rubidium hexafluorophosphate.

9. A tandem solar cell, characterized in that: The invention includes a perovskite solar cell unit, wherein the perovskite solar cell unit comprises a perovskite solar cell as described in any one of claims 1 to 6 or a perovskite solar cell prepared by the preparation method described in any one of claims 7 to 8.

10. The tandem solar cell as described in claim 9, characterized in that: The tandem solar cell is a perovskite / crystalline silicon tandem solar cell, with its top cell including the perovskite solar cell unit and its bottom cell including the crystalline silicon solar cell unit.

11. A battery assembly, characterized in that, The perovskite solar cell includes any one of claims 1 to 6, or a perovskite solar cell prepared by the preparation method according to any one of claims 7 to 8, or a tandem solar cell according to any one of claims 9 to 10.

12. An electrical appliance, characterized in that, The battery includes any one of the perovskite solar cells according to claims 1 to 6, or any one of the tandem solar cells according to claims 9 to 10, or the battery module according to claim 11.

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