Perovskite solar cell and preparation method thereof, laminated cell and photovoltaic module

Abstract

The invention relates to the technical field of new energy, in particular to a perovskite solar cell, a preparation method thereof, a laminated cell and a photovoltaic module. The perovskite solar cell comprises a transparent conductive electrode, a first charge transport layer, a perovskite absorption layer and a second charge transport layer which are stacked, the first charge transport layer or the second charge transport layer comprises a hole transport material, and the hole transport material comprises a compound in a formula I. When the material is applied to a perovskite solar cell as a hole transport material, relatively high photoelectric conversion efficiency can be obtained. Formula I.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to perovskite solar cells and their preparation methods, tandem cells and photovoltaic modules. Background Technology

[0002] In perovskite solar cells, hole transport materials play a crucial role in promoting perovskite nucleation and charge extraction and transport, significantly impacting device efficiency and stability. For example, the bottom hole transport material in inverted perovskite solar cells (PSCs) affects the interface and crystallinity of the perovskite thin film, significantly influencing device performance.

[0003] Compared to inorganic and small-molecule hole transport materials, polymeric hole transport materials (HTMs) offer advantages such as good film formation, tunable energy levels, and high stability, leading to their widespread application in perovskite solar cells. However, commonly used polymeric hole transport materials still suffer from some significant drawbacks. For example, the inherent acidity and hygroscopicity of PEDOT:PSS corrode and accelerate the degradation of perovskite materials, affecting the stability of trans-PSCs; PTAA's high cost ($1980 / g), strong hydrophobicity, and insufficient HOMO energy level increase device instability and cost. Therefore, further development of novel polymeric HTMs is still necessary to obtain low-cost, high-performance, and stable perovskite solar cells. Summary of the Invention

[0004] Based on this, the first aspect of this application provides a perovskite solar cell, the technical solution of which is as follows:

[0005] A perovskite solar cell includes stacked transparent conductive electrodes, a first charge transport layer, a perovskite absorber layer, and a second charge transport layer. The first or second charge transport layer includes a hole transport material, which comprises a compound of formula I.

[0006] Formula I;

[0007] Where L represents C 1-4 Alkylene.

[0008] The second aspect of this application provides a method for fabricating a perovskite solar cell, the technical solution of which is as follows:

[0009] A method for fabricating a perovskite solar cell includes the following steps: sequentially forming a first charge transport layer, a perovskite absorber layer, and a second charge transport layer on a transparent conductive electrode, wherein the first charge transport layer or the second charge transport layer includes a hole transport material, and the method for preparing the hole transport material includes the following steps:

[0010] The compound of formula a undergoes a substitution reaction with the compound of formula b to produce the compound of formula c.

[0011] The compound of formula c is subjected to a substitution reaction with triethyl phosphite to produce compound of formula d;

[0012] The compound of formula d is polymerized with the compound of formula e to produce the compound of formula f;

[0013] Hydrolyze the compound of formula f to generate compound of formula I;

[0014] Formula a; Formula b; Formula c; Formula d; Formula e; Formula f; Formula I;

[0015] In this context, X represents a halogen independently; Y represents a halogen independently; and L represents C. 1-4 Alkylene.

[0016] A third aspect of this application provides a tandem solar cell, comprising a top cell and a bottom cell stacked together, wherein the top cell includes at least one perovskite solar cell, the perovskite solar cell being prepared as described above or by the preparation method described above.

[0017] A fourth aspect of this application provides a photovoltaic module comprising a perovskite solar cell as described above, or a perovskite solar cell prepared by the preparation method described above, or a tandem cell as described above.

[0018] Compared with traditional solutions, this application has the following advantages:

[0019] In the perovskite solar cell of this application, the hole transport material includes a compound of formula I, which possesses good solubility, thermal stability, and film-forming properties, as well as high hole mobility and energy levels matching those of perovskite. Applying this compound as a hole transport material in perovskite solar cells yields good photoelectric conversion efficiency and high reproducibility. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application and to more completely understand this application and its beneficial effects, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1A schematic diagram of the structure of a stacked battery according to one embodiment;

[0022] Figure 2 The NMR spectrum of poly-4PA-DTP;

[0023] Figure 3 SEM scan of the surface morphology of the perovskite layer;

[0024] Figure 4 The cross-sectional morphology of the perovskite layer is shown by SEM scanning. Detailed Implementation

[0025] The present application will be further described in detail below with reference to specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0027] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0028] In this application, the terms "optionally," "optionally," and "optional" refer to options that are optional, meaning they can be selected from either "with" or "without." If multiple "optional" options appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" option is independent.

[0029] In this application, the terms "first aspect," "second aspect," "third aspect," and "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," and "fourth," etc., serve only a non-exhaustive enumeration purpose and should be understood not to constitute a closed limitation on quantity.

[0030] In this application, numerical intervals (i.e. numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the above-mentioned numerical intervals are considered continuous, and include the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical range, as well as every value between the two numerical endpoints.

[0031] In perovskite solar cells, hole transport materials play a crucial role in promoting perovskite nucleation and charge extraction and transport, significantly impacting device efficiency and stability. For example, the bottom hole transport material in inverted perovskite solar cells (PSCs) affects the interface and crystallinity of the perovskite thin film, significantly influencing device performance.

[0032] Compared to inorganic and small-molecule hole transport materials, polymeric hole transport materials (HTMs) offer advantages such as good film formation, tunable energy levels, and high stability, leading to their widespread application in perovskite solar cells. However, commonly used polymeric hole transport materials still suffer from some significant drawbacks. For example, the inherent acidity and hygroscopicity of PEDOT:PSS corrode and accelerate the degradation of perovskite materials, affecting the stability of trans-PSCs; PTAA's high cost ($1980 / g), strong hydrophobicity, and insufficient HOMO energy level increase device instability and cost. Therefore, further development of novel polymeric HTMs is still necessary to obtain low-cost, high-performance, and stable perovskite solar cells.

[0033] This application provides a perovskite solar cell in one embodiment. The perovskite solar cell includes stacked transparent conductive electrodes, a first charge transport layer, a perovskite absorber layer, and a second charge transport layer. The first or second charge transport layer includes a hole transport material, which includes a compound of formula I.

[0034] Formula I;

[0035] Where L represents C 1-4 Alkylene.

[0036] In the aforementioned perovskite solar cells, the hole transport material includes a compound of formula I, which possesses good solubility, thermal stability, and film-forming properties, as well as high hole mobility and energy levels matching those of perovskite. Applying this compound as a hole transport material in perovskite solar cells yields good photoelectric conversion efficiency and high reproducibility.

[0037] Most of the work in the design and synthesis of organic HTMs revolves around the central core. By combining different central cores (such as spirofluorene, thiophene, carbazole, etc.) with methoxy-substituted aromatic amines, HTMs with different properties can be synthesized. This requires us to continuously develop new central cores to improve the diversity of HTMs' structures and properties.

[0038] Dithiophene-pyrrole (DTP), as a multifunctional, electron-rich thiophene fused heterocyclic unit, has a more planar structure and more heteroatoms compared to the thiophene units commonly used in HTMs. The p orbitals occupied by the heteroatoms (S, N) are conjugated with the p orbitals of the aromatic units, enhancing the π-π packing of the molecule and providing stronger electron-donating properties, making DTP a p-type semiconductor and contributing to improved molecular stability. Simultaneously, the S atom can interact with Pb in perovskite. 2+ There are certain interactions that can passivate interface defects on the perovskite surface. Furthermore, the electron-rich nitrogen atoms in DTP can improve the stability of organic semiconductor materials in the oxidized state, enabling optoelectronic devices to have long-term operational stability. This embodiment can adjust the electronic structure, crystallinity, and thermal stability of DTP through reasonable molecular engineering, revealing great potential for undoped HTMs based on the DTP core.

[0039] Self-assembled monolayers (SAMs) have attracted considerable attention in inverted perovskite (PSCs) due to their low cost and simple device fabrication. SAMs are a special class of molecules, their structure generally consisting of three parts: anchoring groups, terminal groups, and linking groups. Anchoring groups typically include phosphoric acid, carboxylic acid, thiols, silanes, and boric acid; different anchoring groups affect contact resistance, work function, and coverage on ITO. Linking groups include aromatic units such as alkyl chains or benzene rings, which influence the molecule's geometry and arrangement. Terminal groups are typically carbazole, triphenylamine, phenothiazine, etc., which can not only extract holes but also modulate energy levels and influence perovskite growth and crystallization.

[0040] Against the theoretical background described above, this embodiment, through reasonable structural design, yields compound of formula I, introducing a promising hole transport material for inverted PSCs and paving the way for higher efficiency and enhanced stability in future devices.

[0041] Optionally, the hole transport material includes at least one of the compounds of formula I-1, I-2, and I-3:

[0042] Formula I-1; Formula I-2; Formula I-3.

[0043] Optionally, n can be 10 to 500.

[0044] In some embodiments, the perovskite solar cell is an inverted perovskite solar cell (PSC), comprising a stacked transparent conductive electrode, a hole transport layer, a perovskite absorber layer, and an electron transport layer, wherein the hole transport layer comprises the aforementioned hole transport material. In some embodiments, the perovskite solar cell further comprises an electron blocking layer, a hole blocking layer, and an interface passivation layer, wherein the electron blocking layer is located between the transparent conductive electrode and the hole transport layer, the hole blocking layer is located on the side of the electron transport layer away from the perovskite absorber layer, and the interface passivation layer is located between the perovskite absorber layer and the electron transport layer.

[0045] A second aspect of this application provides a method for fabricating a perovskite solar cell. In one embodiment, the method includes the following steps: sequentially forming a first charge transport layer, a perovskite absorption layer, and a second charge transport layer on a transparent conductive electrode. The first charge transport layer or the second charge transport layer includes a hole transport material. The method for preparing the hole transport material includes the following steps:

[0046] The compound of formula a undergoes a substitution reaction with the compound of formula b to produce the compound of formula c.

[0047] The compound of formula c is subjected to a substitution reaction with triethyl phosphite to produce compound of formula d;

[0048] The compound of formula d is polymerized with the compound of formula e to produce the compound of formula f;

[0049] Hydrolyze the compound of formula f to generate compound of formula I;

[0050] Formula a; Formula b; Formula c; Formula d; Formula e; Formula f; Formula I;

[0051] In this context, X represents a halogen independently; Y represents a halogen independently; and L represents C. 1-4 Alkylene.

[0052] The above-mentioned method for preparing hole transport materials has low synthesis cost.

[0053] Optionally, the substitution reaction between the compound of formula a and the compound of formula b includes the following steps: mixing the compound of formula a, the compound of formula b, a first catalyst, and a first base agent, and then subjecting the substitution reaction to the reaction.

[0054] Optionally, the first catalyst is selected from tetrabutylammonium bromide. The first base is selected from potassium hydroxide. The temperature at which the substitution reaction of compound a with compound b occurs is 70-90°C. The time for the substitution reaction of compound a with compound b is 12-30 h. The molar ratio of compound a to the first catalyst is 1:(0.1-0.2). The molar ratio of compound a to the first base is 1:(5-25). The molar ratio of compound a to compound b is 1:(40-150).

[0055] Optionally, the temperature at which the compound of formula c undergoes the substitution reaction with triethyl phosphite is 140–150 °C, and the reaction time is 12–16 h. The reaction between the compound of formula c and triethyl phosphite is an Arbuzov reaction. The molar ratio of the compound of formula c to triethyl phosphite is 1:(18–50).

[0056] Optionally, the reaction between compound d and compound e is a Suzuki coupling reaction. The polymerization reaction of compound d and compound e includes the following steps: mixing compound d, compound e, a second catalyst, a second alkali, and a first solvent, followed by the polymerization reaction.

[0057] Optionally, the second catalyst is selected from tetrakis(triphenylphosphine)palladium; the second base agent is selected from potassium carbonate; the first solvent is selected from at least one of toluene, ethanol, and water; the temperature for the polymerization reaction of compound d and compound e is 80-90°C; the polymerization reaction time of compound d and compound e is 24-48 h. The molar ratio of compound d to compound e is (0.8-1.2):(0.8-1.2). The molar ratio of compound d to the second catalyst is 1:(0.03-1). The molar ratio of compound d to the second base agent is 1:(5-8).

[0058] Optionally, hydrolyzing the compound of formula f includes the following steps: dissolving the compound of formula f in a second solvent, adding trimethylbromosilane, and collecting the solid reactant; dissolving the solid reactant in a third solvent and adding water.

[0059] Optionally, the second solvent is selected from 1,4-dioxane. The third solvent is selected from methanol. After adding water, stir for 10-16 hours.

[0060] Crystalline silicon solar cells are the mainstream approach in photovoltaics, primarily categorized into PERC, TOPCon, SHJ, and IBC. They are widely used in new energy power generation and dominate the solar cell market share. However, the efficiency improvement of the crystalline silicon approach has been slow, facing bottlenecks that hinder further advancements. Specifically, after achieving a peak efficiency of 26.3% in 2016, the highest efficiency of the crystalline silicon approach took seven years to reach 27.1%, demonstrating slow and difficult progress. Whether it's TOPCon, HJT, or BC cells, all belong to the crystalline silicon approach, their theoretical efficiency limit is constrained by the Schokui limit of 29.4%, making further improvements difficult.

[0061] To further improve photoelectric conversion efficiency and reduce enterprise costs, researchers and manufacturers are attempting to combine perovskite and crystalline silicon cells, pursuing a commercialization path for perovskite-crystalline silicon tandem solar cells. The tandem cell efficiency ceiling is 44%, 14.6 percentage points higher than crystalline silicon. Since its first recorded efficiency, the perovskite-crystalline silicon tandem route has improved its efficiency from 23.6% to 34.6% in eight years, a much faster rate of improvement than crystalline silicon and even higher than single-cell perovskite cells. The tandem cell efficiency is still far from its theoretical limit, indicating significant room for further improvement. From an efficiency perspective, perovskite-crystalline silicon tandem cells and crystalline silicon exhibit generational differences, making it the most promising route among current photovoltaic technologies. Photovoltaic development has always aimed at cost reduction and efficiency improvement, and tandem cells will be the next stage solution for crystalline silicon.

[0062] Among various perovskite solar cells, pin-type devices have attracted increasing attention due to their mild fabrication process and suitability for tandem cells. Hole transport materials play a crucial role in promoting perovskite nucleation and charge extraction and transport, significantly impacting device efficiency and stability.

[0063] A third aspect of this application provides a tandem solar cell, comprising a top cell and a bottom cell stacked together, wherein the top cell includes at least one perovskite solar cell, the perovskite solar cell being prepared as described above or by the preparation method described above.

[0064] Optionally, the bottom cell includes at least one crystalline silicon cell.

[0065] Optionally, the crystalline silicon cell includes a TOPCon cell. In this case, the tandem cell is a perovskite / TOPCon tandem solar cell. Using the aforementioned hole transport material in the perovskite / TOPCon tandem solar cell achieves better photoelectric conversion efficiency.

[0066] Optionally, the TOPCon cell structure includes an n-type silicon substrate, a p+ emitter on the front side of the n-type silicon substrate, a tunneling oxide layer on the back side of the n-type silicon substrate, and a polycrystalline silicon (poly-Si) thin film on the tunneling oxide layer.

[0067] Optionally, the n-type silicon substrate is n-type monocrystalline silicon, used as the substrate material for the bottom cell, with a thickness of 100-200 μm. The TOPCon cell structure includes a chemical passivation layer on the front side of the n-type silicon substrate and an anti-reflection film on the chemical passivation layer. The chemical passivation layer comprises aluminum oxide with a thickness of 4-5 nm, and the anti-reflection film comprises silicon nitride. The p+ emitter can be formed by boron (B) diffusion, with the doping depth controlled below 5 μm to obtain a suitable surface sheet resistance of 50-150 Ω, thereby establishing an effective electric field on the front side for collecting photogenerated electrons. The tunneling oxide layer comprises at least one of silicon oxide (SiO2) and aluminum oxide (Al2O3), and can be formed by thermal oxidation or plasma-enhanced chemical vapor deposition (PECVD). The deposition thickness of the tunneling oxide layer is 0.8-2 nm. The tunneling oxide is crucial, allowing electrons to tunnel through while blocking holes, achieving carrier selectivity. The polycrystalline silicon thin film has a thickness of 100-200 nm. The preparation method of polycrystalline silicon thin films includes the following steps: forming an amorphous silicon (a-Si) thin film; doping phosphorus atoms into the amorphous silicon thin film to make it an N-type highly doped layer; annealing to crystallize the amorphous silicon and transform it into polycrystalline silicon. Phosphorus atoms can be incorporated into the amorphous silicon thin film through in-situ doping techniques (such as introducing phosphine gas during PECVD) or subsequent phosphorus diffusion (POCl3) processes. The annealing temperature is 800~850℃. This significantly improves passivation and contact performance.

[0068] In one implementation, see Figure 1 The tandem solar cell 100 comprises a crystalline silicon base cell 1, a transparent conductive electrode 2, an electron blocking layer 3, a hole transport layer 4, a perovskite absorber layer 5, an interface passivation layer 6, an electron transport layer 7, a hole blocking layer 8, a front electrode 9, an antireflection layer 10, and a back electrode 11. The crystalline silicon base cell 1 has a front and a back side. The transparent conductive electrode 2 is located on the back side of the crystalline silicon base cell 1. The electron blocking layer 3 is located on the transparent conductive electrode 2. The hole transport layer 4 is located on the electron blocking layer 3, and the hole transport layer 13 includes a hole transport material. The perovskite absorber layer 5 is located on the hole transport layer 4. The interface passivation layer 6 is located on the perovskite absorber layer 5. The electron transport layer 7 is located on the interface passivation layer 6. The hole blocking layer 8 is located on the electron transport layer 7. The front electrode 9 is located on the hole blocking layer 8 and includes a transparent electrode and grid lines. The antireflection layer 11 is located on the front electrode 9. The back electrode 12 is located on the front side of the crystalline silicon base cell 1.

[0069] A fourth aspect of this application provides a photovoltaic module comprising a perovskite solar cell as described above, or a perovskite solar cell prepared by the preparation method described above, or a tandem cell as described above.

[0070] The following description is further illustrated with specific embodiments and comparative examples. Unless otherwise specified, the raw materials involved in the following specific embodiments and comparative examples are all commercially available. Unless otherwise specified, the instruments used are all commercially available. Unless otherwise specified, the processes involved are conventionally selected by those skilled in the art.

[0071] Example 1

[0072]

[0073]

[0074]

[0075] The specific synthetic steps of compound 2 were as follows: Compound 1 (1.02 g, 3 mmol) was added to a 100 mL double-necked flask, and tetrabutylammonium bromide (0.36 g, 0.3 mmol) was dissolved in dibromobutane (15 mL, 125 mmol). Then, a 50% potassium hydroxide aqueous solution (5 mL, 67.5 mmol) was added dropwise. The mixture was heated to 65 °C and stirred overnight (12 h). The reaction mixture was quenched with water and extracted with dichloromethane. The organic layer was dried in combination with anhydrous magnesium sulfate, and the organic solvent was removed by rotary evaporator to obtain the crude product. Further purification was performed by silica gel column chromatography with petroleum ether / dichloromethane = 10 / 1 (v / v) as the eluent to obtain compound 2 (1.06 g, 75% yield).

[0076] The specific synthetic steps of compound 3 were as follows: Compound 2 (1.4 g, 3.0 mmol) and triethyl phosphite (10 mL, 58 mmol) were added to a 100 mL double-necked flask, and the mixture was then heated to 140 °C and stirred overnight (12 h) under a nitrogen atmosphere. The organic solvent was then removed by a rotary evaporator to give 1.3 g of crude product compound 3, with a yield of 85%.

[0077] The specific synthetic steps of compound 5 were as follows: Compound 3 (0.53 g, 1 mmol), compound 4 (0.54 g, 1 mmol), tetrakis(triphenylphosphine)palladium (57 mg, 0.05 mmol), and potassium carbonate (0.83 g, 6 mmol) were added to a 100 mL double-necked flask in a solvent of toluene, ethanol, and water (volume ratio 2:1:1). The mixture was reacted at 85 °C for 6 hours. After cooling to room temperature, the mixture was extracted with DCM, the organic phase was dried over anhydrous Mg2SO4, filtered, distilled under reduced pressure, and finally purified by recrystallization to obtain 0.4 g of compound 5.

[0078] The specific synthetic steps of poly-4PA-DTP are as follows: At room temperature (25°C), 0.4 g of compound 5 and anhydrous 1,4-dioxane (10 mL) were added to a 100 mL double-necked flask, followed by the dropwise addition of trimethylbromosilane (3.06 g, 20 mmol), and stirring overnight (12 h). The 1,4-dioxane was removed using a rotary evaporator to obtain a solid powder. The solid powder was dissolved in methanol (10 mL) at room temperature (25°C), and then deionized water was added dropwise until the mixture became opaque, followed by stirring for another 12 hours. The crude product was collected by filtration and washed with deionized water. The crude product was dissolved in THF (5 mL), precipitated again in acetone (20 mL), and filtered to obtain the final product, poly-4PA-DTP, with a yield of 60%. See the NMR spectrum for details. Figure 2 .

[0079] Example 2

[0080] Following the method of Example 1, dibromobutane was replaced with dibromopropane to obtain the final product poly-3PA-DTP, with the following structure: .

[0081] Example 3

[0082] Following the method of Example 1, dibromobutane was replaced with dibromoethane to obtain the final product poly-2PA-DTP, with the following structure: .

[0083] Example 4

[0084] The steps for fabricating perovskite / TOPCon tandem solar cells are as follows:

[0085] (1) Fabrication of N-type TOPCon crystalline silicon bottom cells

[0086] 1. A 100μm thick n-type monocrystalline silicon wafer is used as the substrate material for the bottom cell. The silicon wafer must be thoroughly cleaned to remove organic contaminants and metal ions to ensure a clean surface with low defects.

[0087] 2. Front Surface Texturing and Passivation: The front surface of the silicon wafer is texturized using an alkaline solution (such as KOH or NaOH) to form a uniform pyramid-shaped microstructure, thereby reducing light reflectivity (target <11%). Subsequently, an ultrathin layer of aluminum oxide (approximately 4~5 nm) is deposited on the front surface as a chemical passivation layer, and covered with a layer of silicon nitride (SiNx) as an anti-reflection film and protective layer.

[0088] 3. Formation of P+ emitter junction: On the front side of the n-type silicon wafer, a P-type doped emitter junction (P+ layer) is formed through a boron (B) diffusion process.

[0089] 4. Backside tunnel oxide layer growth: A very thin silicon dioxide (SiO2) tunnel oxide layer with a thickness of 0.8~2 nm is grown on the backside of the silicon wafer using plasma-enhanced chemical vapor deposition (PECVD).

[0090] 5. An amorphous silicon (a-Si) thin film with a thickness of approximately 100 nm is deposited on top of the tunneling oxide layer. Subsequently, phosphorus atoms are doped into the amorphous silicon to make it an N-type highly doped layer. Then, high-temperature annealing (800~850℃) is performed to crystallize the amorphous silicon and transform it into polycrystalline silicon (poly-Si).

[0091] (2) Fabrication of perovskite top solar cells

[0092] 1. At 350~500℃, a 10~40nm layer of ITO is sputtered onto the back of a crystalline silicon solar cell using a mask as a composite layer, with a contact area of ​​1.1×1.1 cm. 2 Slightly larger than the effective area of ​​the completed stacked battery, 1×1cm 2 The silicon wafer was cut into 2.5 × 2.5 cm pieces. 2 The crystalline silicon substrate is subjected to oxygen plasma treatment for 10-15 minutes.

[0093] 2. Electron blocking layer preparation: At room temperature, a 2-10 nm NiOx layer was deposited on a pre-cleaned silicon / ITO substrate using radio frequency sputtering. The sputtering chamber pressure was 0.40 Pa, the radio frequency power was 90 W, the argon flow rate was 20 sccm, and the deposition time was 5-15 minutes. After deposition, the substrate was annealed in air for 30-40 minutes at 350℃. Subsequently, the silicon / ITO / NiOx substrate was directly transferred to a nitrogen glove box for subsequent spin-coating.

[0094] 3. Preparation of the hole transport layer: Weigh 0.5-3 mg of poly-4PA-DTP, poly-3PA-DTP, and poly-2PA-DTP as hole transport materials, and completely dissolve them in 1 mL of a mixed solution of anhydrous ethanol and DMSO. Take 60-120 μL of the solution and uniformly drop it onto the NiOx layer, allowing it to stand for 5-10 seconds. Spin-coat at 3000 rpm for 25-30 seconds, then anneal at 90-110℃ for 10 minutes. The hole transport layer thickness is 1-20 nm.

[0095] 4. Preparation of perovskite layer precursor: After cooling the crystalline silicon substrate / ITO / NiOx / hole transport layer to room temperature, 0.075 mmol CsI, 1.098 mmol FAI, 0.327 mmol MABr, 0.354 mmol PbBr2, and 1.146 mmol PbI2 were dissolved in 1 mL of a mixed solvent of DMF:DMSO (volume ratio 4:1) to prepare a 1.5 M perovskite precursor solution with the corresponding chemical formula CsI. 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb( I0.77 Br 0.23 3. Form a wide-bandgap perovskite layer with a voltage of 1.68 eV. Spin-coat at 3000-4000 rpm for 30-40 s. 5-7 s before the end of spin-coating, drop 150-200 μL of EA (ethyl acetate) into the center of the film as an anti-solvent. Immediately afterwards, transfer the substrate to a heating stage and anneal at 100 °C for 10 min. The perovskite layer thickness is 400-700 nm.

[0096] 5. Perovskite interface passivation treatment: P201 material is ultrasonically dissolved in isopropanol at a concentration of 0.3 mg / mL. 60-120 μL of the solution is uniformly dropped onto the substrate and spin-coated at 5000 rpm for 25-30 seconds. Then, it is annealed at 90-110℃ for 10 minutes. The thickness of the interface passivation layer is 1-3 nm.

[0097] 6. Fabrication of the electron transport layer: under high vacuum (5×10⁻⁶) -4 At Pa), a 13-30 nm thick C60 layer was thermally evaporated on the perovskite layer (deposition rate 0.1 Å / s).

[0098] 7. Preparation of the hole-blocking layer: under high vacuum (5×10⁻⁶) -4 Under the condition of Pa), a BCP with a thickness of 5~10 nm was thermally evaporated on the upper layer of C60.

[0099] 8. Fabrication of the front electrode: A 40-50 nm thick indium zinc oxide (IZO) layer was deposited on the BCP at room temperature using radio frequency (RF) magnetron sputtering to serve as the transparent electrode (sheet resistance 60 Ω, area defined by a mask of 1.1 × 1.1 cm). 2 The radio frequency power is 80 W. In high vacuum (5×10⁻⁶ W / m²), -4 At Pa), Ag gate lines of 500~800 nm were thermally evaporated on the upper layer of IZO (deposition rate 1 Å / s).

[0100] 9. Preparation of the antireflection layer: under high vacuum (5×10⁻⁶) -4At Pa), MgF2 with a thickness of 95~105 nm was thermally evaporated on the front electrode (deposition rate 0.5 Å / s).

[0101] 10. Preparation of the back electrode Ag: under high vacuum (5×10⁻⁶) -4 At Pa), Ag with a thickness of 300~500nm was thermally evaporated on the front side of the crystalline silicon bottom cell (deposition rate 1Å / s).

[0102] The thicknesses of the C60, BCP, IZO, and MgF2 layers were calibrated using a spectroscopic ellipsometry, and the deposition rate and thickness of each experiment were monitored using a quartz crystal microbalance sensor.

[0103] Test Project

[0104] Project 1: Testing the HOMO level of compound poly-4PA-DTP. 5 mg of poly-4PA-DTP was dissolved in a 0.1 M solution of tetrabutylammonium hexafluorophosphate (Bu4NPF6) in dichloromethane, and ferrocene was used as an external standard for calibration. Cyclic voltammetry curves were obtained on an electrochemical workstation at a purge rate of 0.01 V / s. The redox potentials of the curves were analyzed, and the HOMO of the material was calculated according to the formula. The test results are shown in Table 1.

[0105] Project 2: Testing the hole mobility of compound poly-4PA-DTP. Hole mobility defines the ability of HTLs to extract holes and is one of the important parameters for evaluating the performance of HTMs and even the overall device performance. The space charge-confined current method was used to test hole mobility. A single-hole device of ITO / PEDOT:PSS / HTMs under test / MoO3 / Ag was fabricated, and the thickness of each layer was determined using a profilometer. The JV characteristic curves of the device were obtained under dark conditions using a Keithley 2450 Source-Measure instrument. Nonlinear fitting analysis was performed on the curves to obtain the hole mobility of compound poly-4PA-DTP. The test results are shown in Table 1.

[0106] Table 1

[0107]

[0108] As shown in Table 1, the energy levels of poly-4PA-DTP match those of wide-bandgap perovskite materials, enabling the formation of good ohmic contacts, which is beneficial for hole transport. Furthermore, the high hole mobility of poly-4PA-DTP may improve the fill factor (FF) of the device, and its application in perovskite solar cells is expected to yield superior photovoltaic performance.

[0109] Project 3: Testing the photoelectric conversion efficiency of perovskite / TOPCon tandem solar cells. Under AM 1.5G illumination, the conversion efficiency was 0.02 V / s. -1 The JV curves of the optimal device were measured by forward and reverse scanning, and compared with those of SAMs (2PACZ) commonly used in tandem solar cells. The effective area of ​​the perovskite / TOPCon tandem solar cell was 1 cm². 2 Photovoltaic Index V oc Short-circuit current density (J) sc The fill factor (FF) and PCE are shown in Table 2.

[0110] Table 2

[0111]

[0112] Project 4: To investigate the effect of the more efficient poly-4PA-DTP on the growth of wide-bandgap perovskite crystals, the growth of wide-bandgap perovskite crystals on the poly-4PA-DTP surface was characterized and analyzed by SEM. The surface and cross-section of the perovskite layer formed in Example 4 using poly-4PA-DTP as the hole transport material were scanned using a scanning electron microscope. The surface morphology is shown in [reference needed]. Figure 3 For cross-sectional morphology, please refer to Figure 4 Combining Figure 3 and Figure 4 It can be seen that the perovskite layer grown based on poly-4PA-DTP has a relatively uniform crystal size and no obvious boundary defects. This indicates that poly-4PA-DTP can promote the crystallization and growth of the perovskite layer during the fabrication of PSCs devices, and the perovskite crystals can effectively cover the hole transport layer, which is beneficial to improving the photovoltaic efficiency of the device.

[0113] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0114] The embodiments described above are merely illustrative of 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 the invention patent. 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, characterized in that, The structure includes a stacked transparent conductive electrode, a first charge transport layer, a perovskite absorber layer, and a second charge transport layer. The first or second charge transport layer includes a hole transport material, which includes a compound of formula I. Equation I; Where L represents C 1-4 Alkylene.

2. The perovskite solar cell according to claim 1, characterized in that, The hole transport material includes at least one of the compounds of formula I-1, formula I-2, and formula I-3: Equation I-1; Equation I-2; Formula I-3.

3. The perovskite solar cell according to any one of claims 1 to 2, characterized in that, n is between 10 and 500.

4. A method for fabricating a perovskite solar cell, characterized in that, Includes the following steps: A first charge transport layer, a perovskite absorption layer, and a second charge transport layer are sequentially formed on a transparent conductive electrode. The first or second charge transport layer includes a hole transport material. The method for preparing the hole transport material includes the following steps: The compound of formula a undergoes a substitution reaction with the compound of formula b to produce the compound of formula c. The compound of formula c is subjected to a substitution reaction with triethyl phosphite to produce compound of formula d; The compound of formula d is polymerized with the compound of formula e to produce the compound of formula f; Hydrolyze the compound of formula f to generate compound of formula I; Formula a; Formula b; Formula c; Formula d; Formula e; Formula f; Formula I; In this context, X represents a halogen independently; Y represents a halogen independently; and L represents C. 1-4 Alkylene.

5. The method for preparing a perovskite solar cell according to claim 4, characterized in that, Includes at least one of the following features: (1) The substitution reaction of compound a with compound b includes the following steps: mixing compound a, compound b, a first catalyst and a first base agent, and then the substitution reaction occurs; (2) To cause the compound of formula d to undergo a polymerization reaction with the compound of formula e, the following steps are included: mixing the compound of formula d, the compound of formula e, a second catalyst, a second alkali and a first solvent, and causing a polymerization reaction.

6. The method for preparing a perovskite solar cell according to claim 5, characterized in that, Includes at least one of the following features: (1) The first catalyst is selected from tetrabutylammonium bromide; the first base agent is selected from potassium hydroxide; the temperature at which the compound of formula a and the compound of formula b undergo a substitution reaction is 70~90℃; the time for the substitution reaction between the compound of formula a and the compound of formula b is 12h~30h; (2) The second catalyst is selected from tetra(triphenylphosphine)palladium; the second base agent is selected from potassium carbonate; the first solvent is selected from at least one of toluene, ethanol and water; the temperature at which the compound of formula d reacts with the compound of formula e is 80~90℃; the time for the polymerization reaction of the compound of formula d and the compound of formula e is 24h~48h; (3) The temperature at which the compound of formula c undergoes a substitution reaction with triethyl phosphite is 140~150℃, and the time for the substitution reaction between the compound of formula c and triethyl phosphite is 12h~16h.

7. The method for preparing a perovskite solar cell according to any one of claims 4 to 6, characterized in that, Hydrolyzing the compound of formula f includes the following steps: dissolving the compound of formula f in a second solvent, adding trimethylbromosilane, and collecting the solid reactant; dissolving the solid reactant in a third solvent and adding water.

8. The method for preparing a perovskite solar cell according to claim 7, characterized in that, Includes at least one of the following features: (1) The second solvent is selected from 1,4-dioxane; (2) The third solvent is selected from methanol.

9. A stacked battery, characterized in that, It includes a top cell and a bottom cell stacked together, the top cell including at least one perovskite solar cell, the perovskite solar cell being as described in any one of claims 1 to 3, or being prepared by the preparation method of any one of claims 4 to 8.

10. A photovoltaic module, characterized in that, The invention includes perovskite solar cells according to any one of claims 1 to 3, or perovskite solar cells prepared by the preparation method according to any one of claims 4 to 8, or tandem cells according to claim 9.

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