Preparation method of passivation layer and perovskite solar cell

Abstract

The invention relates to a preparation method of a passivation layer and a perovskite solar cell. The preparation method of the passivation layer comprises the following steps: coating a perovskite light absorption layer with a passivation material precursor solution, and carrying out annealing treatment to form the passivation layer; wherein the passivation material precursor solution comprises a passivation material solute and a ternary combined solvent, and the ternary combined solvent comprises a main solvent, a diluent and a passivation accelerant; the main solvent is used for dissolving a passivation material solute; the diluent and the main solvent are mutually soluble, and the passivation material solute and the perovskite light absorption layer are not dissolved; the passivation accelerant is an aprotic polar solvent containing a P = O group and is mutually soluble with the main solvent. According to the preparation method of the passivation layer and the perovskite solar cell obtained by using the preparation method of the passivation layer, the photoelectric conversion efficiency of the perovskite solar cell can be improved, and meanwhile, the reproducibility and the stability of the perovskite solar cell are further improved.

Description

Technical Field

[0001] This disclosure pertains to the field of perovskite solar cells, and particularly relates to a method for preparing a passivation layer and a perovskite solar cell. Background Technology

[0002] Perovskite solar cells (PSCs) are considered the most promising next-generation photovoltaic technology due to their simple fabrication and high power conversion efficiency (PCE). Over the past decade, various strategies have been proposed to improve the PCE of PSCs, such as bulk doping, energy level tuning, and charge transport. Because of the numerous defects on the surface of the perovskite light-absorbing layer, surface passivation is considered the most effective method to improve PCE. The solvent in the passivation material has a significant impact on the passivation effect; therefore, precise control of the solvent composition and ratio to selectively dissolve the perovskite components is necessary to maximize the potential of surface passivation.

[0003] Isopropanol (IPA) is widely used for surface passivation of various functional layers in perovskite solar cells due to its excellent performance in dissolving passivation materials. However, since formamidine iodide (FAI), a common material for forming the perovskite light-absorbing layer, is soluble in IPA, using passivation materials dissolved in IPA to passivate the perovskite light-absorbing layer (especially formamidine iodide-based films) may create additional defects on the surface of the passivation absorption layer, leading to problems such as poor reproducibility and device instability in perovskite solar cells. Furthermore, besides isopropanol, other solvents currently used to dissolve passivation materials, such as chloroform, are corrosive to the surface of the perovskite light-absorbing layer and may dissolve shallow organic cations (such as M...). This increases halogen vacancy defects. Therefore, there is still considerable room for improvement in the passivation of perovskite light-absorbing layers. Summary of the Invention

[0004] To address the aforementioned technical problems in the passivation of the perovskite light-absorbing layer in existing perovskite solar cells, this disclosure provides a method for passivating the surface of the perovskite light-absorbing layer using a passivation material dissolved in a ternary combined solvent (i.e., a method for preparing a passivation layer on the surface of the perovskite light-absorbing layer) and a perovskite solar cell containing the passivation layer. This method can improve the photoelectric conversion efficiency of perovskite solar cells while further enhancing their reproducibility and stability.

[0005] Specifically, the first aspect of this disclosure provides a method for preparing a passivation layer, the passivation layer being used to passivate the perovskite light-absorbing layer in a perovskite solar cell. The method includes the following steps: coating a passivation material precursor solution onto the perovskite light-absorbing layer, followed by annealing to form the passivation layer; wherein the passivation material precursor solution includes a passivation material solute and a ternary combined solvent, the ternary combined solvent including a main solvent, a diluent, and a passivation promoter; the main solvent is used to dissolve the passivation material solute; the diluent is miscible with the main solvent and does not dissolve the passivation material solute or the perovskite light-absorbing layer; the passivation promoter is an aprotic polar solvent containing P=O groups and is miscible with the main solvent.

[0006] According to the above-described method for preparing the passivation layer, an aprotic polar solvent containing P=O groups was introduced into the passivation material precursor solution as a passivation promoter. This aprotic polar solvent can soften the inorganic framework of the perovskite light-absorbing layer, disrupt the hydrogen bonds of the inorganic framework, and allow some uncoordinated Pb to be present in the perovskite light-absorbing layer. 2+ On the one hand, these uncoordinated Pb 2+ This is unlikely to cause structural collapse of the perovskite light-absorbing layer; on the other hand, these uncoordinated Pb 2+ The perovskite absorber layer forms more stable coordination bonds with P=O groups, which have strong coordination ability, thus better passivating deep-level defects. The principle behind the softening of the inorganic framework of the perovskite absorber layer by aprotic polar solvents is mainly due to the organic cations in the perovskite absorber layer passing through their -NH3 groups. + Group and I - Hydrogen bonds (NH···I) are formed, and nonproton polar solvents have strong Lewis base sites, which are good hydrogen bond acceptors and can break hydrogen bonds. Simultaneously, the oxygen atom of the nonproton polar solvent reacts with the organic cation -NH3. + Groups compete and strongly bind, forming solvent-cation hydrogen bonds. This process strips the hydrogen bonds between the organic cations and the inorganic framework (Pb-I-Pb) of the perovskite absorbing layer. Once the original hydrogen bonds connecting the organic and inorganic components in the perovskite crystal structure are broken and replaced by aprotic polar solvent molecules, the integrity of the inorganic framework of the perovskite absorbing layer is greatly weakened. The organic cations become loose in the cavities, thus softening and swelling the perovskite crystal structure. Furthermore, the interaction between the P=O groups and uncoordinated Pb... 2+ While forming stable coordination bonds, the P=O group, due to its relatively high electronegativity, interacts with Pb in the perovskite light-absorbing layer. 2+ The resulting bond strength is relatively strong, which helps to more effectively passivate deep-level defects in the perovskite light-absorbing layer.

[0007] The aforementioned passivation material precursor solution alters the morphology and state of the grain boundaries between the perovskite light-absorbing layer and its surface, thereby making the perovskite light-absorbing layer appear smoother, more continuous, and with fewer defects at the microscale. This is mainly achieved through two synergistic effects: a nonprotic polar solvent whose P=O bonds are bonded to Pb in the perovskite inorganic framework (Pb-I-Pb). 2+ It possesses strong coordination ability. This coordination selectively softens or even slightly dissolves the areas with the highest energy and least stable surface regions of the perovskite light-absorbing layer, especially the rough tips. According to the "Oswald ripening" principle, small, sharp grains or protrusions have higher surface energy and are more easily dissolved. A large amount of uncoordinated Pb exists at the grain boundaries between grains in the perovskite light-absorbing layer. 2+ These uncoordinated Pb 2+ After being dissolved by the ternary solvent, the perovskite absorber layer is not washed away. Instead, during solvent evaporation, driven by surface tension, it refills the depressions, pores, or cracks on the surface. This eliminates sharp protrusions, fills tiny pores, and makes the film surface smoother and more continuous, narrowing or eliminating gaps at grain boundaries. Therefore, according to the above-described passivation layer preparation method, compared to the conventional passivation precursor solution using IPA as a single solvent to passivate the perovskite absorber layer, the perovskite absorber layer formed in the perovskite solar cell obtained by the above-described passivation layer preparation method has denser grains and fewer grain boundaries, which is beneficial for reducing non-radiative recombination of charge carriers and improving the photoelectric performance of the perovskite solar cell.

[0008] A dense and continuous capping layer composed of passivating materials and aprotic polar solvent-perovskite complex was formed on the surface of the perovskite light-absorbing layer and at the perovskite grain boundaries. This dense film effectively blocks the contact between atmospheric moisture (H2O) and oxygen (O2) and the internal perovskite material. This physical barrier also inhibits the contact between organic components (such as FA) in the perovskite. + ) and halide ions (I - Under certain conditions (such as heating), P=O groups in the aprotic polar solvent will escape from the crystal lattice and volatilize, thus maintaining the stability of the perovskite composition. The uncoordinated Pb groups on the perovskite surface and at grain boundaries... 2+The formation of stable coordination bonds makes it difficult for the active lead sites to react with external substances. Furthermore, the functional groups such as -NH2 in passivating materials like propylenediamine iodine (PDADI) can form hydrogen bonds or ionic interactions with the perovskite absorber surface, further stabilizing the interface. Due to the passivation effect of the ternary solvent combination, the sharp parts of the perovskite absorber surface are slightly dissolved, allowing the perovskite to release some mechanical stress and preventing microcracks from forming in the perovskite film during thermal cycling. This results in a tighter and smoother contact between the perovskite absorber layer and the upper second carrier transport layer, reducing contact resistance and barriers at the interface, while also preventing interlayer delamination and improving the mechanical stability of the cell. Therefore, compared to passivation methods using IPA as a single solvent, the perovskite solar cells prepared using the above passivation layer preparation method exhibit better stability and slower efficiency decay.

[0009] Preferably, in the method for preparing the passivation layer according to the first aspect of this disclosure, the volume ratio of the main solvent to the diluent is 1:9 to 1:1.

[0010] By controlling the volume ratio of the main solvent to the diluent within the aforementioned range, the diluent can suppress the main solvent from damaging the perovskite light-absorbing layer and reduce the destructive effect of the main solvent. Furthermore, because the main solvent primarily dissolves the passivation material solute, a volume ratio of the main solvent to the diluent lower than 1:9 will result in insufficient dissolution of the passivation material solute in the passivation material precursor solution; when the ratio exceeds 1:1, the diluent's effect in suppressing the main solvent's damage to the perovskite light-absorbing layer is relatively poor.

[0011] Preferably, in the method for preparing the passivation layer according to the first aspect of this disclosure, the passivation promoter has a volume percentage of 0.01% to 0.1% in the ternary combined solvent.

[0012] By controlling the volume percentage of the passivation accelerator in the ternary solvent within the aforementioned range, the passivation accelerator can penetrate the perovskite absorber layer more effectively, thus better repairing defects in the perovskite absorber layer and preventing the dissolution of perovskite crystals within the absorber layer. Studies have found that when the volume percentage of the passivation accelerator in the ternary solvent is below 0.01%, the passivation accelerator cannot penetrate the perovskite absorber layer well, resulting in poor defect repair. This is because the passivation accelerator needs a sufficient volume percentage to effectively repair deep-level defects. Furthermore, if the volume percentage of the passivation accelerator in the ternary solvent is too high, for example, exceeding 0.1%, it can actually cause the well-crystallized perovskite absorber layer to dissolve, leading to device failure.

[0013] Preferably, in the method for preparing the passivation layer according to the first aspect of this disclosure, the main solvent is isopropanol or chloroform, and the passivation material can be well dissolved using the above-mentioned main solvent.

[0014] Preferably, in the method for preparing the passivation layer according to the first aspect of this disclosure, the diluent is at least one selected from anisole, chlorobenzene, and ethyl acetate. As described in the background art, when isopropanol (IPA) is used as the sole solvent for the passivation material, it inevitably damages the surface of the perovskite light-absorbing layer, thereby generating additional defects, especially FA (acetic acid). + Vacancies. According to the aforementioned passivation layer preparation method, after the passivation material is fully dissolved, a diluent such as anisole is added to reduce the amount of IPA, greatly mitigating damage to the perovskite light-absorbing layer. As a result, the formed perovskite light-absorbing layer has denser grains and fewer grain boundaries, which helps reduce non-radiative recombination of charge carriers and improves the photoelectric performance, reproducibility, and stability of perovskite solar cells.

[0015] Preferably, in the method for preparing the passivation layer according to the first aspect of this disclosure, the passivation promoter is hexamethyltriamine phosphate (HMPA). The dual passivation of P=O+triamine groups in hexamethyltriamine phosphate can achieve Pb... 2+ Dual passivation of defects and iodine vacancy defects simultaneously repairs Pb / I defects. Furthermore, the hexamethyltriamine phosphate (HMPA) used as a passivation promoter in this invention is a small liquid molecule compound with a molecular weight of only 179.20, which facilitates penetration into the perovskite light-absorbing layer, thereby promoting the penetration of the passivation material solute into the perovskite light-absorbing layer and ensuring its full reaction, deeply penetrating the bulk phase to passivate defects. In addition, HMPA possesses a unique trimethyl hydrophobic barrier, comprehensively improving the humidity / thermal / light stability of the perovskite solar cell. In use, compared to solid passivating agents requiring complex dissolution steps, HMPA can be added directly, and as a promoter, it has a wide concentration window (0.01 vol%-0.1 vol%). Specifically, assuming the ternary combined solvent is 1 mL, the volume of HMPA added can be within the range of 0.1-1 μL. Therefore, compared to compounds that require precise control of the concentration process window, hexamethyltriamine phosphate (HMPA) is better able to avoid solvent damage and is more conducive to industrialization.

[0016] Preferably, in the method for preparing the passivation layer according to the first aspect of this disclosure, the volume ratio of the main solvent to the diluent is 1:9 to 1:1, and the volume percentage of the passivation promoter in the ternary combined solvent is 0.01 to 0.1%.

[0017] Preferably, the main solvent is isopropanol or chloroform, the diluent is at least one of anisole, chlorobenzene and ethyl acetate, and the passivation promoter is triammonium hexamethylphosphate.

[0018] According to the above-described method for preparing the passivation layer, the technical effects that can be obtained by the passivation layer preparation method described above can be achieved.

[0019] Preferably, in the method for preparing the passivation layer according to the first aspect of this disclosure, the passivation material solute is at least one selected from propylenediamine iodide, phenylethylamine iodide, and 4-methoxyphenylethylamine iodide. Propylenediamine iodide (PDA) These technologies can achieve dual-site synergistic passivation, improved thermal stability, and optimized interface energy level matching. Phenylethyl iodide (PEAI) can achieve significant defect passivation, strong process compatibility, and improved stability. 4-Methoxyphenylethylamine iodide (MeO-PEAI) can achieve significant defect passivation, optimized grain morphology, and enhanced stability.

[0020] Preferably, in the method for preparing the passivation layer according to the first aspect of this disclosure, the annealing temperature is 100°C to 120°C, and the annealing time is 5 min to 15 min.

[0021] According to the above-described method for preparing the passivation layer, limiting the annealing temperature and time to the aforementioned range can promote defect passivation. The annealing process provides energy for the interaction between the passivating agent molecules and the surface of the perovskite absorber layer, thereby effectively reducing the defect state density. This can significantly reduce non-radiative recombination, improve the optoelectronic performance of the device, stabilize the structure of the perovskite absorber layer, and a suitable annealing temperature helps the passivating agent molecules form a stable passivation layer in the perovskite absorber layer without causing changes to the bulk structure of the perovskite absorber layer. When the annealing temperature is too high (i.e., exceeding the above-described range), it may cause the passivation layer itself to decompose or fail, and may exacerbate the thermal degradation of the active layer itself in the perovskite absorber layer; while when the annealing temperature is too low (i.e., below the above-described range), it may not provide sufficient energy for the chemical reaction between the passivating agent and the perovskite absorber layer, resulting in insufficient defect passivation and failure to achieve the optimal passivation effect. If the annealing time is too long (i.e., exceeds the above-mentioned limit), it may cause unnecessary chemical changes in the passivation layer or perovskite light-absorbing layer and reduce production efficiency; while if the annealing time is too short (i.e., below the above-mentioned limit), the annealing process may not be fully completed.

[0022] A second aspect of this disclosure provides a perovskite solar cell, comprising a substrate, a first carrier transport layer, a perovskite light-absorbing layer, a passivation layer, a second carrier transport layer, and a metal electrode, sequentially stacked. The passivation layer is characterized in that it is prepared using the passivation layer preparation method according to the first aspect of this disclosure. The perovskite solar cell of the second aspect achieves the same technical effects as the passivation layer preparation method of the first aspect.

[0023] The preparation method of the passivation layer according to the first aspect of this disclosure, the basic structure of the perovskite solar cell according to the second aspect, and their effects have been described above. The details will now be described in conjunction with the accompanying drawings for better understanding. Attached Figure Description

[0024] The accompanying drawings are provided to better understand the invention and are not intended to unduly limit the scope of the invention. Wherein: Figure 1 This is a schematic diagram of a perovskite solar cell structure according to an embodiment of the present invention; Figure 2 This is a comparison chart of steady-state and transient fluorescence (PL) spectra of the perovskite light-absorbing layer of the perovskite solar cells of Embodiments 1, 6, and 9 of the present invention and the perovskite solar cell of Comparative Example 1. Figure 3 This is a comparison chart of steady-state and transient time-resolved fluorescence (TRPL) spectra of the perovskite light-absorbing layer in the perovskite solar cells of Examples 1, 6, and 9 of the present invention and Comparative Example 1. Figure 4 This is a comparison graph of the JV (current density-voltage) curves of the perovskite solar cell according to Example 1 of the present invention and the perovskite solar cell according to Comparative Example 1. Figure 5 These are cell efficiency statistics of the perovskite solar cells according to Examples 1, 6, and 9 of the present invention and the perovskite solar cell according to Comparative Example 1; Figure 6 The diagram shows the cell efficiency statistics of the perovskite solar cell according to Example 4 of the present invention and the perovskite solar cell according to Comparative Example 3. Figure 7 This is a scanning electron microscope (SEM) cross-sectional view of the perovskite in the perovskite solar cell according to Embodiment 1 of the present invention; Figure 8 The image is a cross-sectional view of the perovskite in the perovskite solar cell of Comparative Example 1, obtained using a scanning electron microscope (SEM).

[0025] Reference tag list

[0026] 10 base

[0027] 21 First Carrier Transport Layer

[0028] 22 Perovskite light-absorbing layer

[0029] 30 passivation layer

[0030] 40 Second Carrier Transport Layer

[0031] 50 Buffer Layer

[0032] 60 Transparent conductive oxide layer

[0033] 70 Metal Electrode

[0034] 80 anti-reflection layer Detailed Implementation

[0035] The technical solution of the present invention will be described more clearly below by referring to the accompanying drawings and specific embodiments.

[0036] It should be noted that the accompanying drawings of this invention are merely schematic diagrams for clearly illustrating parts related to the present invention and do not show some unnecessary parts. Therefore, these drawings should not be construed as limiting the invention, and may differ from the actual structure in use. Furthermore, it should be understood that terms indicating orientation or position such as "up," "down," "left," "right," "front," and "rear" that may appear in the following description are for convenience of explanation and not restrictive. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0037] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined to form new technical solutions. Unless otherwise specified, all technical features and optional technical features of the present invention can be combined to form new technical solutions. Unless otherwise specified, the terms "comprising" and "including" in the present invention are open-ended or closed-ended. For example, "comprising" and "including" may mean that other components not listed may also be included, or only the listed components may be included.

[0038] This invention provides a method for manufacturing perovskite solar cells, which uses a ternary combined solvent to synergistically improve the surface of the perovskite light-absorbing layer, thereby obtaining a high-quality perovskite light-absorbing layer. In the ternary combined solvent system, a diluent is mixed into the main solvent (e.g., isopropanol) to dissolve a passivation material solute such as propylenediamine iodine (PDADI), while a passivation promoter such as hexamethyltriamine phosphate (HMPA) is added to soften the perovskite inorganic framework, promote the penetration of the passivation material solute, and further effectively passivate deep-level defects in the thin film.

[0039] Figure 1 This is a schematic diagram of an example of a perovskite solar cell according to an embodiment of the present invention.

[0040] like Figure 1 As shown, the present invention provides a perovskite solar cell, which includes a substrate 10, a first carrier transport layer 21, a perovskite light-absorbing layer 22, a passivation layer 30, a second carrier transport layer 40, and a metal electrode 70 stacked sequentially.

[0041] The substrate 10 can be conductive glass or a crystalline silicon solar cell substrate. The crystalline silicon solar cell substrate can be a heterojunction (HJT) crystalline silicon solar cell, a tunnel oxide passivated contact (TOPCon) crystalline silicon solar cell, a back contact (BC) crystalline silicon solar cell, etc. Alternatively, the substrate 10 can also be a single-junction perovskite solar cell.

[0042] Understandably, if substrate 10 is conductive glass, the aforementioned perovskite solar cell is a single-junction perovskite solar cell. If substrate 10 is a crystalline silicon solar cell substrate, the aforementioned perovskite solar cell is a crystalline silicon / perovskite tandem solar cell. If substrate 10 is a single-junction perovskite solar cell, the aforementioned perovskite solar cell is a perovskite / perovskite tandem solar cell.

[0043] Furthermore, if the substrate 10 is conductive glass, the conductive glass may include insulating glass and a conductive film layer disposed on one side of the insulating glass, with the aforementioned first carrier transport layer 21 disposed on the conductive film layer. If the substrate 10 is a crystalline silicon cell substrate, the uppermost layer of the crystalline silicon cell substrate may be a conductive film layer, with the aforementioned first carrier transport layer 21 disposed on the conductive film layer. The conductive film layer may be, for example, FTO (fluorine-doped tin oxide) and ITO (indium tin oxide), materials with high light transmittance and good conductivity suitable for use as conductive film layers in perovskite cells.

[0044] The first carrier transport layer 21 can be an electron transport layer, and correspondingly, the second carrier transport layer 40 is a hole transport layer (perovskite solar cells are conventional structural devices). Alternatively, the first carrier transport layer 21 can also be a hole transport layer, and correspondingly, the second carrier transport layer 40 is an electron transport layer (perovskite solar cells are inverted structural devices). For the hole transport layer, it can be nickel oxide (NiO). x Examples of suitable materials include poly(3,4-ethylenedioxythiophene poly(styrene sulfonate)) (PEDOT:PSS), Spiro-MeOTAD (2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene), and CuSCN (copper phthalocyanine). Preferably, nickel oxide (NiO) is selected. x As a hole transport layer, it can be constructed, for example, by sputtering nickel oxide (NiO) onto a substrate 10. X This is achieved through [method / process]. Alternatively, other common materials and processes can be used to form the hole transport layer. The electron transport layer can be made of C60 (a spherical molecule composed of 60 carbon atoms), which has excellent electron transport capabilities. Alternatively, other common materials used for electron transport layers can also be used.

[0045] Passivation layer 30 is used to passivate the perovskite light-absorbing layer 22 in a perovskite solar cell. The method for preparing passivation layer 30 includes the following steps: coating a passivation material precursor solution onto the perovskite light-absorbing layer 22, followed by annealing to form passivation layer 30. The passivation material precursor solution includes a passivation material solute and a ternary combined solvent. The ternary combined solvent includes a main solvent, a diluent, and a passivation promoter. The main solvent is used to dissolve the passivation material solute. The diluent is miscible with the main solvent but does not dissolve the passivation material solute or the perovskite light-absorbing layer 22. The passivation promoter is an aprotic polar solvent containing P=O groups and is miscible with the main solvent.

[0046] The method of coating the passivation material precursor solution onto the perovskite light-absorbing layer 22 can include spin coating, spray coating, and blade coating.

[0047] The passivation material solute forming the passivation layer 30 can be one of propylene diamine iodide (PDADI), phenylethyl iodide (PEAI), 4-methoxyphenylethylamine iodide (MeO-PEAI), or any combination thereof.

[0048] The main solvent for forming the passivation layer 30 can be isopropanol (IPA), chloroform, etc.

[0049] The diluent that forms the passivation layer 30 can be one of anisole, chlorobenzene (CB), ethyl acetate (EA), or any combination thereof.

[0050] Furthermore, in the passivation layer preparation method according to embodiments of the present invention, the volume ratio of the main solvent (e.g., IPA) to the diluent (e.g., anisole) in the passivation material precursor solution is 1:9 to 1:1, for example, 1:9, 1:4 (2:8), 3:7, 2:3 (4:6), 1:1 (5:5), etc. Specifically, the amount of the main solvent (e.g., IPA) and the diluent (e.g., anisole) in 1 mL of the passivation material precursor solution can be 100 μL:900 μL, 200 μL:800 μL, 300 μL:700 μL, 400 μL:600 μL, or 500 μL:500 μL.

[0051] The passivation promoter forming the passivation layer 30 can be hexamethyltriamine phosphate (HMPA), which is an aprotic polar solvent with P=O double bonds. Alternatively, the passivation promoter forming the passivation layer can be a combination of hexamethyltriamine phosphate (HMPA) and other aprotic polar solvents with P=O double bond groups.

[0052] Furthermore, in the passivation layer preparation method according to embodiments of the present invention, the passivation promoter (e.g., hexamethyltriamine phosphate (HMPA)) in the passivation material precursor solution has a volume percentage of 0.01% to 0.1% in the ternary combined solvent. For example, the amount of passivation promoter in 1 mL of the passivation material precursor solution can be 0.1 μL, 0.2 μL, 0.3 μL, 0.4 μL, 0.5 μL, 0.6 μL, 0.7 μL, 0.8 μL, 0.9 μL, or 1 μL.

[0053] The annealing temperature in the method for preparing the passivation layer 30 can be from 100°C to 120°C, such as 105°C, 110°C, 115°C, 120°C, etc., and the annealing time can be from 5 min to 15 min, such as 5 min, 8 min, 10 min, 15 min, etc.

[0054] The metal electrode 70 can be made of materials such as gold or silver. Considering production costs, silver is preferred as the material for the metal electrode 70. However, other common materials used for metal electrodes can also be used. It is even possible to consider replacing the metal electrode with a composite electrode.

[0055] In addition, the perovskite solar cell may optionally include a buffer layer 50 covering the second carrier transport layer 40. The buffer layer 50 may be made of materials such as tin oxide, zinc oxide, aluminum oxide, titanium oxide, and zinc sulfide. Tin oxide (SnO2) is preferred. Common fabrication processes include atomic layer deposition (ALD), magnetron sputtering, and solution coating. Other common materials and processes may also be used to form the buffer layer 50.

[0056] In addition, the perovskite solar cell optionally includes a transparent conductive oxide layer 60 covering the buffer layer 50. The transparent conductive oxide layer 60 is also known as the TCO layer, and common TCO materials include indium zinc oxide (IZO), indium tin oxide (ITO), fluorine-doped tin oxide (FTO), and aluminum-doped zinc oxide (AZO). Indium zinc oxide (IZO) is preferred. Common TCO layer fabrication techniques include in-line deposition and offline deposition. In-line deposition mainly uses chemical vapor deposition (CVD), while offline deposition commonly uses magnetron sputtering (PVD). Other common materials and processes can also be used to form the transparent conductive oxide layer 60.

[0057] In addition, perovskite solar cells may optionally include an antireflection layer 80 covering the metal electrode 70. The antireflection layer 80 uses a material with a low refractive index, such as LiF and MgF2. These materials reduce light reflection at the cell surface, allowing light to penetrate the cell surface more easily, enter the active layer, and be effectively absorbed. Furthermore, the design of the antireflection layer 80 can also address current mismatch issues in tandem cells, further optimizing cell performance. The antireflection layer 80 can be formed using other common materials and common processes (such as vapor deposition).

[0058] The effects and functions of the perovskite solar cells and their manufacturing methods according to embodiments of the present invention will be explained below with reference to specific examples and comparative examples.

[0059] <Examples and Comparative Examples>

[0060] Example 1: The method for manufacturing a perovskite solar cell according to Embodiment 1 of the present invention includes the following steps: Step 1: Sputter nickel oxide (NiO) onto the crystalline silicon solar cell substrate with the IZO composite junction already formed. X A nickel oxide hole transport layer was obtained, wherein the thickness of the nickel oxide was 15 nm. Step 2: Spin-coat a perovskite light-absorbing layer onto the nickel oxide hole transport layer obtained in Step 1. Specifically, dissolve CsI, FAI, PbBr2, and PbI2 in DMF (dimethylformamide) / DMSO (dimethyl sulfoxide) (volume ratio 4:1) to achieve a molar concentration of 1.75 M FAI per mL. 0.75 Cs 0.25 Pb(I 0.8 Br 0.2 The sample contained 113.67 mg CsI, 225.71 mg FAI, 192.68 mg PbBr2, 564.74 mg PbI2, 200 μL DMSO, and 800 μL DMF. The mixture was stirred at room temperature for 4 h to obtain a perovskite precursor solution. The precursor solution was then spin-coated onto the substrate treated in step 1 using a two-step method (the first spin-coating had an initial speed of 500 rpm, an acceleration of 500 rpm, and a spin-coating time of 2 s; the second spin-coating had an initial speed of 2000 rpm, an acceleration of 2000 rpm, and a spin-coating time of 60 s). 180 μL of chlorobenzene (CB) antisolvent was added dropwise 10 s before the end of the second spin-coating. After spin-coating, the substrate was annealed on a hot plate at 100 °C for 20 min to obtain a perovskite light-absorbing layer. Step 3: A passivation layer is formed on the perovskite light-absorbing layer obtained in Step 2. The specific process is as follows: 1 mg PDADI is dissolved in 400 μL of isopropanol (IPA) as the main solvent, then 600 μL of anisole is added as a diluent, and finally 0.1 μL of hexamethyltriamine phosphate (HMPA) is added as a passivation promoter. The mixture is stirred at room temperature for 4 h to obtain a passivation material precursor solution. The passivation material precursor solution is then spin-coated onto the surface of the perovskite light-absorbing layer treated in Step 2. The spin-coating process is as follows: 80 μL of the passivation material precursor solution is spread evenly on the surface of the perovskite light-absorbing layer and spin-coated at 4000 rpm for 30 s. After spin-coating, the mixture is annealed on a hot plate at 100℃ for 10 min to obtain the passivation layer. Step 4: An electron transport layer is formed on the passivation layer obtained in step 3. The specific process is as follows: a 15 nm thick C60 is deposited using a vapor deposition equipment at a rate of 1 Å / s to obtain the electron transport layer. Step 5: Form SnO2 (buffer layer) on the electron transport layer obtained in step 4. The specific process is as follows: deposit a 14 nm thick SnO2 using an atomic deposition (ALD) device to obtain the buffer layer. Step 6: Form an IZO (transparent conductive oxide TCO layer) layer on the buffer layer obtained in step 5. The specific process is as follows: deposit a 35 nm thick IZO layer using a magnetron sputtering (PVD) device to obtain the TCO layer. Step 7: Form a metal electrode on the TCO layer. The specific process is as follows: deposit a 700 nm thick Ag layer on the TCO layer obtained in step 6 by vapor deposition at a rate of 1 Å / s. Step 8: Form a MgF2 antireflection layer on the metal electrode. The specific process is as follows: 100 nm thick MgF2 is deposited on the metal electrode obtained in step 7 at a rate of 1 Å / s using the vapor deposition method to obtain the final perovskite solar cell.

[0061] Example 2: Example 2 differs from Example 1 in that the amount of passivation promoter added is different. Specifically, in step 3, the amount of hexamethyltriamine phosphate (HMPA) added is adjusted to 0.5 μL, while the other steps are the same.

[0062] Example 3: Example 3 differs from Example 1 in that the amount of passivation promoter added is different. Specifically, in step 3, the amount of hexamethyltriamine phosphate (HMPA) added is adjusted to 1 μL, and the remaining steps are the same.

[0063] Example 4: Example 4 differs from Example 2 in that the volume ratio of the main solvent to the diluent is different. Specifically, in step 3, 1 mg of PDADI is dissolved in 100 μL of isopropanol (IPA), and then 900 μL of anisole is added as a diluent; the remaining steps are the same.

[0064] Example 5: Example 5 differs from Example 2 in that the volume ratio of the main solvent to the diluent is different. Specifically, in step 3, 1 mg of PDADI is dissolved in 500 μL of isopropanol (IPA), and then 500 μL of anisole is added as a diluent; the remaining steps are the same.

[0065] Example 6: Example 6 differs from Example 1 in that the diluent used is different. Specifically, in step 3, 1 mg of PDADI is dissolved in 400 μL of isopropanol (IPA), and then 600 μL of chlorobenzene (CB) is added as a diluent; the remaining steps are the same.

[0066] Example 7: Example 7 differs from Example 6 in that the amount of passivation promoter added is different. Specifically, in step 3, 0.5 μL of hexamethyltriamine phosphate (HMPA) is added as a passivation promoter, and the remaining steps are the same.

[0067] Example 8: Example 8 differs from Example 6 in that the amount of passivation promoter added is different. Specifically, in step 3, 1 μL of hexamethyltriamine phosphate (HMPA) is added as a passivation promoter, and the remaining steps are the same.

[0068] Example 9: Example 9 differs from Example 1 in that the diluent used is different. Specifically, in step 3, 1 mg of PDADI is dissolved in 400 μL of isopropanol (IPA), and then 600 μL of ethyl acetate (EA) is added as a diluent; the remaining steps are the same.

[0069] Example 10: Example 10 differs from Example 9 in that the amount of passivation promoter added is different. Specifically, in step 3, 0.5 μL of hexamethyltriamine phosphate (HMPA) is added as a passivation promoter, and the remaining steps are the same.

[0070] Example 11: Example 11 differs from Example 9 in that the amount of passivation promoter added is different. Specifically, in step 3, 1 μL of hexamethyltriamine phosphate (HMPA) is added as a passivation promoter, and the remaining steps are the same.

[0071] Comparative Example 1: The difference between Comparative Example 1 and Example 1 lies in step 3. Specifically, step 3 of Comparative Example 1 is as follows: 1 mg of PDADI is dissolved in 1 mL of isopropanol (IPA), and stirred at room temperature for 4 h to obtain a passivation material precursor solution. The remaining steps are the same.

[0072] Comparative Example 2: Comparative Example 2 differs from Example 2 in that the volume ratio of the main solvent to the diluent is different. Specifically, in step 3, 1 mg of PDADI is dissolved in 100 μL of isopropanol (IPA), and then 1000 μL of anisole is added as a diluent; the remaining steps are the same.

[0073] Comparative Example 3: Comparative Example 3 differs from Example 2 in that the volume ratio of the main solvent to the diluent is different. Specifically, in step 3, 1 mg of PDADI was dissolved in 600 μL of isopropanol (IPA), and then 400 μL of anisole was added as a diluent; the remaining steps were the same.

[0074] Comparative Example 4: Comparative Example 4 differs from Example 1 in the amount of passivation accelerator added. Specifically, in step 3, hexamethylphosphonic triamine is not added, while the remaining steps are the same.

[0075] Comparative Example 5: Comparative Example 5 differs from Example 1 in the amount of passivation accelerator added. Specifically, in step 3, 1.1 μL of hexamethyltriamine phosphate (HMPA) was added as a passivation accelerator, while the remaining steps were the same.

[0076] Comparative Example 6: Comparative Example 6 differs from Example 6 in that the volume ratio of the main solvent to the diluent is different. Specifically, in step 3, 1 mg of PDADI was dissolved in 600 μL of isopropanol (IPA), and then 400 μL of chlorobenzene was added as a diluent; the remaining steps were the same.

[0077] Table 1 shows the transient fluorescence spectroscopy (TRPL) test results of the perovskite absorber layer in the perovskite solar cells of Examples 1 to 11. Table 2 shows the transient fluorescence spectroscopy (TRPL) test results of the perovskite absorber layer in the perovskite solar cells of Comparative Examples 1 to 6.

[0078] Table 1

[0079] Table 2

[0080] Furthermore, in order to clearly illustrate the differences between the test results of the embodiments and the comparative examples, and to avoid overlapping and intersecting curves in the test graphs of each embodiment, this invention selected test results from some embodiments and some comparative examples for comparison. Figures 2 to 7 Provide illustrations.

[0081] Figure 2 This is a comparison of steady-state and transient fluorescence (PL) spectra of the perovskite absorber layer in a perovskite solar cell using a ternary combined solvent (corresponding to Example 1 using anisole as a diluent, Example 6 using chlorobenzene as a diluent, and Example 9 using ethyl acetate as a diluent, respectively) according to embodiments of the present invention, and a perovskite solar cell using pure IPA solvent according to Comparative Example 1. Figure 2 It can be seen that: First, compared with the use of pure IPA solvent (Comparative Example 1), the peak position of the perovskite absorber layer of the perovskite solar cell using the ternary combined solvent according to the present invention remains unchanged at 741 nm, proving that the use of the ternary combined solvent does not affect the band gap; Second, the intensity of the PL peak changes after changing the diluent (anisole, chlorobenzene, ethyl acetate), and both are better than those using pure IPA solvent (Comparative Example 1), indicating that passivation with the ternary combined solvent improves the crystallinity of the perovskite absorber layer and reduces the nonradiative recombination of charge carriers.

[0082] Figure 3 This is a comparison of steady-state and transient time-resolved fluorescence (TRPL) spectra of the perovskite absorber layer in a perovskite solar cell using a ternary combined solvent (corresponding to Example 1 using anisole as a diluent, Example 6 using chlorobenzene as a diluent, and Example 9 using ethyl acetate as a diluent, respectively) according to embodiments of the present invention, and a perovskite solar cell using pure IPA solvent according to Comparative Example 1. Figure 3 As shown in Table 1, after replacing pure IPA (Comparative Example 1) with the ternary combined solvent provided in the embodiments of the present invention, τ avg The significant increase in (average carrier lifetime) (e.g., from 512.2 ns to 897.3 ns in Example 1 compared to Comparative Example 1) indicates that the ternary combined solvent reduces the defect state density on the perovskite film surface, which is beneficial to improving the fill factor (FF) of the calcium-silicon tandem cell.

[0083] Figure 4 This is a comparison chart of the JV curves of a perovskite solar cell using a ternary combined solvent (using anisole as a diluent) according to Example 1 of the present invention and a perovskite solar cell using pure IPA solvent according to Comparative Example 1. Figure 4 The curves show that the efficiency improvement of perovskite solar cells using ternary combined solvents compared to using pure IPA solvent is attributed to V. OCThe increase in FF is consistent with the test results of the aforementioned PL and TRPL tests.

[0084] Figure 5 This is a statistical graph showing the cell efficiency of a perovskite solar cell using a ternary combined solvent (corresponding to Example 1 using anisole as a diluent, Example 6 using chlorobenzene as a diluent, and Example 9 using ethyl acetate as a diluent, respectively) according to embodiments of the present invention, and a perovskite solar cell using pure IPA solvent according to Comparative Example 1. Figure 5 It is known that the maximum power conversion efficiency (PCE) of perovskite solar cells using pure IPA solvent passivator is approximately 30.05%, and the average PCE is approximately 29.2%. However, according to embodiments of the present invention, the PCE of perovskite solar cells using a ternary combined solvent is improved, particularly the perovskite solar cells using anisole as a diluent, where the maximum PCE reaches 32.18%, and the average is above 31%. Furthermore, the reproducibility and stability of perovskite solar cells passivated with the ternary combined solvent are further improved.

[0085] Figure 6 This is a statistical graph showing the cell efficiency of the perovskite solar cell according to Example 4 of the present invention and the perovskite solar cell according to Comparative Example 3. (As shown by...) Figure 6 As can be seen from the battery efficiency statistics, the perovskite solar cell prepared according to Example 4 has a more concentrated efficiency distribution, and the reproducibility of the battery efficiency above 30% is high. In contrast, the perovskite solar cell prepared according to Comparative Example 3 has a more dispersed distribution, and the reproducibility of the efficiency above 30% is poor. This proves that the perovskite solar cell of Example 4 is better than that of Comparative Example 3 in improving battery yield and reproducibility.

[0086] Figure 7 This is a perovskite scanning electron microscope (SEM) cross-section of a perovskite solar cell using a ternary combined solvent (using anisole as a diluent) according to Example 1 of the present invention, and Figure 8 This is a cross-sectional image of the perovskite solar cell using pure IPA solvent from Comparative Example 1, obtained via scanning electron microscopy (SEM). Figure 7 and Figure 8 It can be seen that the grains in the perovskite light-absorbing layer treated with ternary combined solvents are more compact, coherent, and crack-free, and the grain size is also larger. Larger grains and fewer grain boundaries are beneficial to improving the carrier transport efficiency between the perovskite light-absorbing layer and the C60 electron transport layer.

[0087] It should be noted that, combining Tables 1 and 2, and Figures 2 to 7It can be seen that, although the average carrier lifetime is not significantly improved when using anisole, chlorobenzene and ethyl acetate as diluents, considering all factors, it should be considered that using anisole, chlorobenzene and ethyl acetate as diluents can achieve better results than using pure isopropanol in perovskite solar cells.

[0088] Regarding the volume ratio of main solvent to diluent: (1) By comparing the test results of Examples 2, 4, and 5 with Comparative Example 2 in Tables 1 and 2, it can be seen that under the condition that the diluent is anisole and the content of passivation accelerator HMPA is the same, Examples 2, 4, and 5 control the volume ratio of the main solvent to the diluent within the range of 1:9 to 1:1. However, when the diluent anisole accounts for too large a proportion (for example, Comparative Example 2), its τ1 value is larger, τ avg The values ​​are also relatively small, indicating that excessive dilution caused by excessive anisole damages the passivation layer formation, leading to a decrease in passivation layer quality, exacerbating carrier recombination, and reducing lifetime. (2) By comparing Examples 2 and 5 with Comparative Example 3 in Tables 1 and 2, it can be seen that under the condition that the diluent is anisole and the content of passivation accelerator HMPA is the same, Examples 2 and 5 control the volume ratio of the main solvent to the diluent in the range of 1:9 to 1:1. However, when the proportion of anisole in the diluent is too small (for example, Comparative Example 3), its τ2 value (compared to Examples 2 and 5) is smaller. avg The values ​​are also relatively small, indicating that IPA excessively erodes the perovskite, causing defects in the bulk phase and insufficient surface passivation, resulting in a reduced lifetime; furthermore, although the carrier lifetime (τ) of Example 4 is relatively small... avg = 583.4 ns) slightly lower than Comparative Example 3 (τ avg = 624 ns), but the difference was not significant. However, in the formulation of Example 4 (IPA: anisole = 1:9), the anisole content was high, and its corrosivity was much lower than that of Comparative Example 3 (6:4). This means: a wider process window, that is, the formulation of Example 4 is not sensitive to fluctuations in process parameters such as spin coating speed and ambient temperature / humidity, and it is easier to stably reproduce high-quality results in different batches and on different equipment; and lower risk, that is, Example 4 almost completely avoids the risk of damage to the perovskite film due to excessive solvent erosion, ensuring high production yield. Refer to the above regarding Figure 6 Explanation; (3) Compared with Comparative Example 6, in Tables 1 and 2, under the condition that the diluent is chlorobenzene and the content of passivation accelerator HMPA is the same, Example 6 controls the volume ratio of the main solvent to the diluent in the range of 1:9 to 1:1. However, when the diluent chlorobenzene accounts for too small a proportion (for example, Comparative Example 6), its τ1, τ2, and τ avgThe values ​​were all lower than those in Example 6, indicating that excessive IPA over-eroded the perovskite, causing defects in the bulk phase and insufficient surface passivation, resulting in a reduced lifespan. Compared to Comparative Example 6, the volume ratio of the main solvent IPA and the diluent chlorobenzene in Example 6 enabled the solvent system to have moderate corrosivity, effectively passivating the surface without damaging the bulk phase, thus achieving an overall reduction in composite degradation.

[0089] Regarding the volume percentage of passivation accelerator in the ternary combined solvent

[0090] (1) Compared with Comparative Example 4, in Examples 1 and 2 of Tables 1 and 2, where the diluent is anisole and the volume ratio of the main solvent IPA to the diluent anisole is the same (4:6), the volume percentages of the passivation accelerator HMPA in the ternary combined solvent of Examples 1 and 2 are 0.01% and 0.05%, respectively, while the content of the passivation accelerator HMPA in Comparative Example 4 is 0. It can be seen that τ2 and τ avg Both were significantly lower than in Examples 1 and 2, indicating that the lack of the key passivation accelerator HMPA prevents the passivator from anchoring defects, leading to increased surface recombination (τ2↓) and consequently lower overall performance (τ). avg The decrease (↓) proves that HMPA is irreplaceable in the ternary system—its function of softening the skeleton is a necessary prerequisite for triggering effective passivation; (2) Compared with Comparative Example 4, in both Tables 1 and 2, when the diluent is anisole and the volume ratio of the main solvent IPA to the diluent anisole is the same (4:6), the passivation accelerator HMPA in Example 3 has a volume percentage of 0.1% in the ternary combined solvent, while in Comparative Example 4 it is 0%. It can be seen that τ1 in Comparative Example 4 is smaller than τ2 and τ... avg The slightly higher value indicates that the lack of HMPA means that passivation only reaches the surface physical coverage level and cannot effectively repair deep-level defects, proving that passivation promoters are crucial for improving bulk phase quality. (3) Compared with Comparative Example 5, in Examples 1 and 2 of Tables 1 and 2, when the diluent is anisole and the volume ratio of the main solvent IPA to the diluent anisole is the same (4:6), the volume percentages of the passivation accelerator HMPA in the ternary combined solvent of Examples 1 and 2 are 0.01% and 0.05%, respectively, while the volume percentage of the passivation accelerator HMPA in the ternary combined solvent of Comparative Example 5 is 0.11%. It can be seen that τ2 and τ avg The values ​​were significantly lower than those in Examples 1 and 2, indicating that excessive HMPA (more than 0.1%) caused over-softening, which damaged the surface structure, leading to a sharp drop in τ2 and deterioration of overall performance. (4) Compared with Comparative Example 5, in both Tables 1 and 2, when the diluent is anisole and the volume ratio of the main solvent IPA to the diluent anisole is the same (4:6), the volume percentage of passivation promoter HMPA in the ternary combined solvent of Example 3 is 0.1%, while the volume percentage of passivation promoter HMPA in the ternary combined solvent of Comparative Example 5 is 0.11%. It can be seen that although the average carrier lifetime τ of Comparative Example 5 is 0.11%, the volume percentage of passivation promoter HMPA in the ternary combined solvent is 0.11%. avg While not significantly inferior to Example 3, the decrease in τ1 and increase in τ2 compared to Comparative Example 5 indicate that harmful non-radiative recombination in the film was effectively suppressed, while beneficial radiative recombination potential was released. This directly foreshadows superior optoelectronic device performance.

[0091] In summary, this invention provides a technical solution for synergistically improving the surface of the perovskite light-absorbing layer in perovskite solar cells using a ternary combined solvent, thereby obtaining a high-quality perovskite light-absorbing layer. In the ternary combined solvent system, the main component is a diluent (e.g., anisole, chlorobenzene, ethyl acetate, etc., solvents that hardly dissolve perovskite), mixed with an appropriate proportion of IPA or chloroform to dissolve passivation materials such as propylenediamine iodine (PDADI), while simultaneously adding a non-protic polar solvent with P=O groups, such as hexamethyltriamine phosphate (HMPA), to soften the perovskite inorganic framework, thereby promoting the penetration of the passivation material.

[0092] Compared to methods using IPA as a single passivating agent in the manufacture of perovskite solar cells, the present invention's technique of using a ternary combined solvent to synergistically improve the surface of the perovskite light-absorbing layer results in a more compact perovskite light-absorbing layer with fewer grain boundaries. This reduces non-radiative recombination of charge carriers, improves the photoelectric performance of the perovskite solar cell, and also produces a more stable perovskite solar cell with slower efficiency decay. Therefore, the present invention's technique of using a ternary combined solvent to synergistically improve the surface of the perovskite light-absorbing layer has a wide range of applications and is suitable for most formaldehyde-based perovskite systems.

[0093] In existing technologies, the reaction between IPA as a passivating agent in a single solvent and the perovskite absorbing layer is insufficient. This invention, however, introduces hexamethyltriamine phosphate (HMPA), a nonprotic polar solvent that softens the perovskite framework. The P=O groups in HMPA possess strong coordination ability, enabling them to react with uncoordinated Pb in the perovskite absorbing layer. 2+ Stable coordination bonds are formed, and the P=O group has relatively high electronegativity, which interacts with Pb in the perovskite light-absorbing layer. 2+The resulting bond strength is relatively strong, which helps to more effectively passivate deep-level defects. The dual passivation of the P=O + triamine groups in hexamethyltriamine phosphate enables dual passivation of Pb defects and iodine vacancy defects, simultaneously repairing Pb / I defects. Furthermore, the passivation promoter hexamethyltriamine phosphate used in this invention is a liquid small-molecule compound with a molecular weight of only 179.20, which facilitates penetration into the perovskite light-absorbing layer, thereby promoting the penetration of the passivation material solute into the perovskite light-absorbing layer for sufficient reaction and deep penetration into the bulk phase to passivate defects. In addition, hexamethyltriamine phosphate possesses a unique trimethyl hydrophobic barrier, comprehensively improving the humidity / thermal / light stability of perovskite solar cells. In use, compared to solid passivation agents requiring complex dissolution steps, hexamethyltriamine phosphate can be added directly, and its 2F-PAE as a promoter has a wide concentration window (0.01-0.1 vol%). Specifically, assuming the passivation material precursor solution is 1 mL, the volume of HMPA added can be within the range of 0.1-1 μL. Therefore, compared to compounds that require precise control of the concentration process window, HMPA is better at avoiding solvent damage and is more conducive to industrialization.

[0094] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for preparing a passivation layer, wherein the passivation layer is used to passivate the perovskite light-absorbing layer in a perovskite solar cell, characterized in that, The method includes the following steps: A passivation material precursor solution is coated onto the perovskite light-absorbing layer, and then annealed to form the passivation layer. The passivation material precursor solution includes a passivation material solute and a ternary combined solvent, wherein the ternary combined solvent includes a main solvent, a diluent, and a passivation promoter. The main solvent is used to dissolve the passivation material solute; The diluent is miscible with the main solvent and does not dissolve the passivation material solute or the perovskite light-absorbing layer; The passivation promoter is an aprotic polar solvent containing P=O groups and is miscible with the main solvent.

2. The method for preparing the passivation layer according to claim 1, characterized in that, The volume ratio of the main solvent to the diluent is 1:9 to 1:

1.

3. The method for preparing the passivation layer according to claim 1, characterized in that, The passivation accelerator is present in the ternary combined solvent at a volume percentage of 0.01% to 0.1%.

4. The method for preparing the passivation layer according to claim 1, characterized in that, The main solvent is isopropanol or chloroform.

5. The method for preparing the passivation layer according to claim 1, characterized in that, The diluent is at least one of anisole, chlorobenzene, and ethyl acetate.

6. The method for preparing the passivation layer according to claim 1, characterized in that, The passivation accelerator is hexamethylphosphonic triamine.

7. The method for preparing the passivation layer according to claim 1, characterized in that, The volume ratio of the main solvent to the diluent is 1:9 to 1:1, and the passivation accelerator in the ternary combined solvent has a volume percentage of 0.01% to 0.1%. And / or, The main solvent is isopropanol or chloroform, the diluent is at least one of anisole, chlorobenzene and ethyl acetate, and the passivation promoter is triammonium hexamethylphosphate.

8. The method for preparing the passivation layer according to any one of claims 1 to 7, characterized in that, The passivation material solute is at least one of propylenediamine iodide, phenylethyl iodide, and 4-methoxyphenylethylamine iodide.

9. The method for preparing the passivation layer according to any one of claims 1 to 7, characterized in that, The annealing temperature is 100°C to 120°C, and the annealing time is 5 min to 15 min.

10. A perovskite solar cell, comprising a substrate, a first carrier transport layer, a perovskite light-absorbing layer, a passivation layer, a second carrier transport layer, and a metal electrode stacked sequentially, characterized in that, The passivation layer is prepared by the passivation layer preparation method according to any one of claims 1 to 9.

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