A passivation layer solution, a preparation method of a perovskite thin film and a photoelectric device

Abstract

The present application relates to a kind of passivation layer solution, the preparation method of perovskite film and photoelectric device, passivation layer solution includes multiple passivation agent, multiple the passivation agent at least includes first passivation agent and second passivation agent, the molecular structure of the first passivation agent includes electron-donating group and electron-accepting group that can form intermolecular hydrogen bond, the molecular structure of the second passivation agent includes strong electronegativity atom or group.The bifunctional passivation ability that first passivation agent can simultaneously interact with perovskite surface multiple defect sites, the second passivation agent solves the problem of unevenness of first passivation agent, can obtain better repeatability, higher reliability passivation effect, lay the foundation for the manufacture of high performance, high uniformity perovskite module.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to a passivation layer solution, a method for preparing perovskite thin films, and optoelectronic devices. Background Technology

[0002] Perovskite photovoltaic technology represents a major breakthrough in the photovoltaic field in recent years, demonstrating its enormous application potential and commercial value. This technology, with its excellent photoelectric conversion efficiency, low-cost manufacturing process, and abundant raw material sources, has become a focus of attention for research institutions and industries worldwide. The active layer of perovskite solar cells (PSCs) is composed of metal halide perovskites, typically with the chemical formula ABX3, where the A-site is a monovalent cation (e.g., Cs). + MA + (CH3NH3 + ), FA + (CH(NH2) 2+ The B site is a divalent cation (e.g., Pb). 2+ Sn 2+ The X position is a monovalent halide anion (e.g., Cl). - ,Br - I - These ions are connected by angle-sharing BX6 octahedra to form the cubic crystal structure of perovskite. This unique structure endows it with advantages such as high carrier mobility, high light absorption coefficient, and long carrier diffusion distance. The power conversion efficiency (PCE) of PSCs has increased from the initial 3.8% to 26.95%, demonstrating the enormous potential of perovskite photovoltaic technology. The next decade will be a golden age for perovskite photovoltaic technology, with widespread applications expected in ground-mounted power plants, aviation, buildings, wearable power generation devices, and many other fields. Simultaneously, with the continuous maturation of the technology and further reduction in cost, perovskite solar cells are expected to replace traditional crystalline silicon solar cells as the mainstream commercial product. Despite the numerous advantages of perovskite photovoltaic technology and its significant progress in commercialization, its full industrialization still faces a series of technical and process challenges.

[0003] The performance of perovskite solar cells is largely constrained by the high density of defects on their thin film surface and at grain boundaries. These defects, acting as non-radiative recombination centers, not only lead to a loss of photoelectric conversion efficiency but also accelerate device degradation, hindering their commercialization. Specifically, rapid nucleation and growth of perovskite crystals generates a large number of dangling bonds, halogen vacancies, and uncoordinated ions at grain boundaries and on the surface. Among these, halogen vacancies (V0.05) are particularly prevalent. x ) and uncoordinated lead ions (Pb) 2+The most common and most harmful defect states are the open-circuit voltage (V0). These defects form deep-level defects in the band gap of perovskites, acting as nonradiative recombination centers that trap photogenerated carriers and dissipate their energy through phonon vibrations, thus leading to an open-circuit voltage (V0). oc The significant loss of surface defects (Pb) and fill factor (FF) results in experimental efficiency far below the theoretical limit. Even more serious is the fact that these surface defects, especially uncoordinated Pb... 2+ and halogen vacancies (V x + These lattices are not only recombination centers but also the starting points for moisture and oxygen intrusion, as well as rapid channels for ion migration. They can induce the decomposition of the perovskite lattice and exacerbate performance degradation under illumination, electric fields, and thermal stress, severely limiting the long-term operational stability of the device.

[0004] This problem is particularly pronounced in large-area thin films fabricated using slot coating technology. While slot coating offers advantages such as high throughput and scalability, its process characteristics also introduce additional defect formation pathways: mismatch between coating speed and solvent system can lead to poor crystallization consistency, resulting in multi-scale grain boundaries and pores; the cutter height directly affects the wet film thickness and uniformity, increasing surface roughness and lattice distortion; and when coating in an ambient atmosphere (such as air), the instantaneous intrusion of moisture and oxygen not only interferes with the crystallization process but also increases halogen vacancy-related defects. These process-sensitive factors collectively result in a significantly higher defect density in large-area thin films compared to laboratory spin-coated samples, severely limiting module performance and stability. Summary of the Invention

[0005] To address the aforementioned shortcomings, this invention proposes a passivation layer solution, a method for preparing perovskite thin films, and an optoelectronic device. By introducing PZDI and TOPO to construct a synergistic passivation system, the efficiency and stability of large-area perovskite components can be improved.

[0006] The technical solution adopted in this invention is a passivation layer solution comprising multiple passivating agents, wherein the multiple passivating agents include at least a first passivating agent and a second passivating agent. The molecular structure of the first passivating agent includes electron-donating groups and electron-accepting groups that can form intermolecular hydrogen bonds, and the molecular structure of the second passivating agent includes strongly electronegative atoms or groups.

[0007] Preferably, the strongly electronegative atoms or groups of the second passivating agent are capable of coordinating with uncoordinated lead ions on the perovskite surface.

[0008] Preferably, the first passivating agent comprises a salt formed by organic amines, amidines, guanidines or their derivatives and hydrohalic acids, or a salt formed by amino acids and hydrohalic acids; the second passivating agent comprises phosphoxy, carbonyl or sulfonyl groups.

[0009] Preferably, the first passivating agent is piperazine dihydroiodate, and the second passivating agent is trioctylphosphine oxide.

[0010] Preferably, the mass ratio of the trioctylphosphine oxide to the piperazine dihydroiodate is (2.5:1) to (4:1).

[0011] Preferably, it further includes a first solvent in which various passivating agents are dissolved, wherein the first solvent is one or more of isopropanol, ethanol, methanol, acetonitrile, ethyl acetate, toluene, chlorobenzene, N,N-dimethylformamide or dimethyl sulfoxide.

[0012] This invention also discloses a method for preparing perovskite thin films, comprising the following steps: S100, Obtain the perovskite light-absorbing layer; S200. Apply the above passivation layer solution to the surface of the perovskite light-absorbing layer to form a passivation film. S300. The passivation film is processed to form a passivation layer covering the surface of the perovskite light-absorbing layer.

[0013] Preferably, the method for obtaining the perovskite light-absorbing layer of S100 is as follows: it is prepared by one of the following methods: slot coating, blade coating, spray coating, inkjet printing, screen printing, or roll-to-roll coating; and / or The method by which the passivation layer solution is applied to the surface of the perovskite light-absorbing layer in S200 is one of the following: slot coating, blade coating, spray coating, inkjet printing, screen printing, or roll-to-roll coating.

[0014] Preferably, the treatment of the passivated film includes an annealing step, wherein the annealing temperature is 90°C to 120°C and the annealing time is 3 to 10 minutes.

[0015] The present invention also discloses an optoelectronic device comprising a perovskite thin film prepared by the above-described preparation method.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The first passivating agent possesses bifunctional passivation capability, simultaneously interacting with multiple defect sites on the perovskite surface (e.g., uncoordinated lead ions and halogen vacancies). The second passivating agent's molecular structure includes strongly electronegative atoms or groups, which act as competitive hydrogen bond acceptors, interacting with electron-donating groups in the first passivating agent molecule. This competitive interaction effectively breaks the self-aggregation of hydrogen bonds between the first passivating agent molecules, promoting a more uniform dispersion of the first passivating agent molecules in the solution, and ultimately achieving a more uniform and denser passivation layer on the perovskite surface. The second passivating agent solves the problem of inhomogeneity of the first passivating agent, thus ensuring that the excellent bifunctional passivation capability of the first passivating agent can be fully and consistently realized. By solving the self-agglomeration problem of the first passivating agent, the passivation layer solution of this embodiment can achieve better repeatability and higher reliability when applied to large-area perovskite films, especially through solution methods such as slot coating and blade coating, laying the foundation for the manufacture of high-performance, highly uniform perovskite modules. The second passivating agent, with its high electronegativity and ability to provide lone pairs of electrons, can also react with the abundant and significantly harmful uncoordinated Pb on the perovskite surface. 2+ The defect leads to strong and stable coordination bonding.

[0017] 2. This invention significantly improves the efficiency and stability of large-area perovskite modules by introducing a synergistic passivation system of PZDI and TOPO. The core mechanism lies in the fact that the strongly polar phosphooxy group (P=O) in the TOPO molecule can form P=O···HN hydrogen bonds with the amine group (NH) in the PZDI molecule, effectively competing with and breaking the NH···I hydrogen bonds that PZDI easily forms. This inhibits the self-aggregation of PZDI molecules on the perovskite surface, promoting the formation of a uniformly distributed and dense passivation layer, greatly improving the repeatability and reliability of the passivation process. Simultaneously, the P=O group of TOPO supports the uncoordinated Pb... 2+ It possesses strong coordination ability, enabling more stable and thorough passivation of deep-level defects, thus overcoming the insufficient passivation capability of a single PZDI system. PZDI, on the other hand, continues to play a role in passivating Pb. 2+ The bifunctional effects of halogen vacancies and perovskite are combined to significantly suppress nonradiative recombination on the perovskite surface and at grain boundaries, extend carrier lifetime, and improve the photoelectric conversion efficiency of the device. In addition, the uniform and stable passivation layer also blocks the erosion of moisture and oxygen and slows down ion migration, thereby significantly enhancing the stability of the device under long-term operation.

[0018] 3. Based on the above mechanism, using a combination of PZDI and TOPO as passivating agents enables more comprehensive and uniform defect passivation of the perovskite surface, thereby significantly improving the photoelectric conversion efficiency and long-term stability of the final device. The improved photoelectric conversion efficiency stems from the effective suppression of non-radiative recombination and the enhanced carrier extraction capability; the improved stability benefits from the effective barrier of the uniform and stable passivation layer against ion migration and environmental corrosion; furthermore, this hybrid passivation strategy has strong process compatibility and can be applied to large-area deposition technologies such as slot coating. Without increasing complex steps or significant costs, it improves production yield and the consistency of module performance, providing an economical and reliable solution for the commercialization of perovskite solar cells. Attached Figure Description

[0019] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein: Figure 1 This is a schematic diagram of the molecular structure of the first passivating agent; Figure 2 This is a schematic diagram of the molecular structure of the second passivating agent; Figure 3 This is the molecular structure diagram of piperazine dihydroiodate; Figure 4 This is the molecular structure diagram of trioctylphosphine oxide; Figure 5 This is a dynamic light scattering particle size distribution diagram; Figure 6 This is a test graph of the photoelectric conversion efficiency of a large-area perovskite module; Figure 7 This is a stability test diagram of a large-area perovskite module. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] To suppress defects at the surface and grain boundaries of perovskite thin films, this invention discloses a passivation layer solution, relating to a general synergistic passivation strategy. In one embodiment, the passivation layer solution includes multiple passivating agents, wherein the multiple passivating agents include at least a first passivating agent and a second passivating agent.

[0022] The molecular structure of the first passivating agent includes electron-donating and electron-accepting groups that can form intermolecular hydrogen bonds, such as molecules containing both amine groups and halide ions. This specific molecular structure endows the first passivating agent with bifunctional passivation capabilities, enabling it to interact simultaneously with multiple defect sites on the perovskite surface (e.g., uncoordinated lead ions and halide vacancies). However, this structural characteristic also allows for strong intermolecular interactions between the first passivating agent molecules through these groups, leading to its tendency to self-aggregate in solution and during film formation, forming unevenly distributed aggregates. This severely limits the full utilization and reproducibility of its inherent passivation capabilities.

[0023] The second passivating agent comprises a strongly electronegative atom or group in its molecular structure. This strongly electronegative atom or group can act as a competitive hydrogen bond acceptor, interacting with the electron-donating group in the first passivating agent molecule. This competitive interaction effectively breaks the self-aggregation of hydrogen bonds between the first passivating agent molecules, allowing the first passivating agent molecules to be more uniformly dispersed in the solution, ultimately achieving a more uniform and dense passivation layer on the perovskite surface. The second passivating agent solves the problem of inhomogeneity of the first passivating agent, thus ensuring that the excellent bifunctional passivation capability of the first passivating agent can be fully and consistently realized.

[0024] Furthermore, by solving the self-agglomeration problem of the first passivating agent, the passivation layer solution of this embodiment can achieve a passivation effect with better repeatability and higher reliability when applied to large-area perovskite thin films, especially through solution methods such as slot coating and blade coating, laying the foundation for the manufacture of high-performance, high-uniformity perovskite modules.

[0025] In one embodiment, the second passivating agent preferably has a group that has a strong coordination ability to perovskite surface defects, typically a molecule containing groups such as P=O, C=O, S=O, etc., and the strong electronegative atoms or groups of the second passivating agent can coordinate with uncoordinated lead ions on the perovskite surface.

[0026] The scheme of this embodiment enables the second passivating agent to play a dual functional role in the system. First, its highly electronegative atoms or groups (such as the O atom in P=O) act as efficient hydrogen bond acceptors, forming competitive hydrogen bonds with the electron-donating groups in the first passivating agent molecule, effectively solving the problem of uniform dispersion of the first passivating agent as mentioned above. Second, and this is the core of this embodiment, other electron-donating sites in the same group or molecule, with their high electronegativity and ability to provide lone pairs of electrons, can interact with the abundant and significantly harmful uncoordinated Pb on the perovskite surface. 2+ The defect leads to strong and stable coordination bonding.

[0027] This coordination interaction produced significant beneficial effects, enabling the targeting of deep-level defects on the perovskite surface, particularly uncoordinated Pb.2+ The passivation effect is more thorough and robust than that achieved when using the first passivating agent alone. Therefore, the second passivating agent in this scheme is not only a dispersant that promotes the uniform dispersion of the first passivating agent, but also an enhanced passivating agent that directly participates in defect passivation and provides additional passivation strength. The combination of the two constructs a more complete and efficient defect suppression system, which is expected to significantly improve the open-circuit voltage and photoelectric conversion efficiency of the device.

[0028] The surface passivation technology using the passivation layer solution in this embodiment is highly compatible with slot coating processes, can be implemented over large areas, and is highly efficient and stable, which is crucial for advancing the industrialization of perovskite solar cells. The passivation strategy can adapt to real-world conditions such as high-speed coating, atmospheric environments, and roll-to-roll production, achieving uniform and robust passivation layer coverage even under complex defect state distributions. This effectively suppresses nonradiative recombination, improves device efficiency, and ultimately meets the comprehensive requirements of cost, efficiency, and stability for large-scale manufacturing.

[0029] In one embodiment, the aforementioned synergistic passivation strategy can also be extended to other combinations of functional passivating agents, as long as they satisfy the synergistic mechanism of "one agent for dispersion and one agent for enhanced passivation".

[0030] In one embodiment, the first passivating agent comprises a salt formed from an organic amine, amidine, guanidine or its derivatives and a hydrohalic acid, or a salt formed from an amino acid and a hydrohalic acid; the second passivating agent comprises a phosphoroyl group, a carbonyl group or a sulfonyl group.

[0031] The first passivating agent includes, but is not limited to: salts formed from organic amines, amidines, guanidines or their derivatives and hydrohalic acids (HX, X = F, Cl, Br, I); or salts formed from amino acids and hydrohalic acids; or any molecular structure that simultaneously contains a proton donor group (such as a primary ammonium group -NH3). + Secondary ammonium group -NH2R + amide group -CONH - (etc.) and hydrogen bond acceptor groups (such as halogen anions X) - Carboxylate-COO - sulfonate-SO3 - The first passivating agent can be a compound with the following molecular structures: cyano-CN, carbonyl-C=O, etc., and exhibiting a tendency to self-aggregate due to intermolecular hydrogen bonding. Figure 1 One of the structural formulas or its derivatives.

[0032] The second passivating agent can be extended to any strongly electronegative atom or group (such as phosphoxy, carbonyl, sulfonyl, etc.) that can form competitive hydrogen bonds with the proton donor of the first passivating agent, and preferably also contains atoms or groups that can interact with perovskite surface defects (especially uncoordinated Pb). 2+The molecules of the coordinating atoms or groups, wherein the molecular structure of the second passivating agent can be Figure 2 One of the structural formulas or its derivatives.

[0033] In one embodiment, the synergistic passivation system is not limited to a combination of two components, but can be extended to a combination of three or more components. For example, a third, fourth, or more functional molecules can be introduced, which can further optimize the dispersibility, defect passivation capability, energy level matching with adjacent layers, hydrophobicity, or stability of the passivation layer. As long as the combination as a whole follows the synergistic mechanism of "one component readily self-aggregates, while another (or several) components inhibit its aggregation through competitive interactions and provide additional passivation or functional enhancement," it falls within the scope of protection of this patent.

[0034] In one embodiment, the first passivating agent is piperazine dihydroiodate, and the second passivating agent is trioctylphosphine oxide.

[0035] When large-area perovskite films are prepared using only PZDI passivation slit coating, intermolecular hydrogen bonding easily leads to uneven distribution and aggregation on the perovskite surface, making it difficult to form a uniform, dense, and stable passivation coating. This aggregation phenomenon severely limits the controllability and consistency of defect passivation, resulting in poor process repeatability and a significant bottleneck in device performance improvement. Furthermore, PZDI also affects the passivation of uncoordinated Pb. 2+ Its limited coordination ability and insufficient passivation strength for deep-level defects also restrict its application potential in large-area modules.

[0036] To address the aforementioned technical challenges, this embodiment provides a synergistic passivation scheme, namely, introducing TOPO as a synergistic passivating agent into PZDI. This process exhibits good adaptability and scalability, is compatible with production lines of different scales, and provides an effective material solution for the commercialization of perovskite solar cells.

[0037] Piperazine dihydroiodate (PZDI), as a typical passivating agent, contains I in its molecule. - Ions can effectively passivate halide ions, while protonated amine groups (NH) can interact with uncoordinated Pb groups on the surface. 2+ Ion interactions theoretically enable synergistic passivation of perovskite defects at two sites. However, when PZDI is used to passivate large-area perovskite films prepared by slit coating processes, the I atoms in a single PZDI molecule... -PZDI readily forms intermolecular hydrogen bonds (NH···I) with hydrogen atoms (NH) on the amine groups of other molecules. This hydrogen bonding causes PZDI molecules to self-aggregate on the perovskite surface, forming unevenly distributed aggregates instead of the ideal uniform coverage. This uneven passivation layer makes the defect passivation effect uncontrollable, severely affecting the repeatability and reliability of the process, ultimately leading to a bottleneck in improving device performance.

[0038] See Figure 3 The amino group on the protonated piperazine ring in the PZDI molecule It has a high electron cloud density, which can provide lone pairs of electrons to the uncoordinated Pb on the perovskite surface. 2+ The ions form stable coordination bonds, achieving effective passivation of lead defects; simultaneously, the iodide ions (I₂) in its molecule... - PZDI can interact with surface halogen vacancies or exposed halogen sites, thereby repairing anion defects. This dual passivation mechanism enables PZDI to synergistically passivate cation and anion defects on the perovskite surface, significantly suppressing nonradiative recombination and contributing to improved carrier lifetime and device open-circuit voltage. However, it is precisely the amino groups present in its molecular structure that... and iodide ions (I - This leads to the tendency of PZDI to undergo intermolecular self-aggregation: In a PZDI molecule, the more electronegative Ig - It can react with the hydrogen of the amino group in a neighboring molecule. Forming a strong Hydrogen bonds. This strong intermolecular interaction makes it difficult for PZDI molecules to achieve a uniform monolayer distribution, making them prone to forming aggregated structures. This results in uneven passivation layer coverage, insufficient passivation of local defects, and ultimately affects the repeatability and stability of device performance.

[0039] See Figure 4 The phosphorus-oxygen double bond (P=O) in the tri-n-octylphosphine oxide (TOPO) molecule has strong polarity and high electronegativity. Its oxygen atom can provide a lone pair of electrons as an excellent hydrogen bond acceptor, which interacts with the amine protons in the piperazine dihydroiodate (PZDI) molecule. Form a stable Hydrogen bonds. This competitive interaction effectively blocks the original hydrogen bonds between PZDI molecules. Hydrogen bonding inhibits the self-aggregation of PZDI on the perovskite surface, promoting the formation of a uniformly distributed and densely arranged passivation layer, significantly improving passivation consistency and process repeatability. Simultaneously, the lone pair electrons provided by the phosphorus-oxygen bonds in the TOPO molecule interact with the uncoordinated Pb on the perovskite surface. 2+The ions form more stable coordination bonds than PZDI, achieving more thorough and efficient passivation of lead defects. This synergistic mechanism not only solves the problem of PZDI dispersion uniformity but also enhances the passivation strength for deep-level defects, thus jointly contributing to a significant improvement in device open-circuit voltage, fill factor, and long-term stability.

[0040] In one embodiment, a comparative experiment was conducted. The experimental group used a mixed solution of PZDI and TOPO as the passivation layer solution, while the control group used a PZDI solution as the passivation layer solution. The experimental results are shown below. Figure 5 , Figure 6 and Figure 7 .

[0041] Dynamic light scattering (DLS) was used to characterize the particle size distribution of single piperazine dihydroiodate (PZDI) solution and a mixed passivating agent solution of PZDI and trioctylphosphine oxide (TOPO). Figure 5 Dynamic light scattering (DLS) particle size distribution analysis revealed that the dominant particle size in the PZDI solution was concentrated around 340 nm, while in the mixed solution of PZDI and TOPO, the dominant particle size significantly decreased to 254.1 nm. This result indicates that the introduction of TOPO effectively suppressed the self-aggregation behavior of PZDI molecules, significantly improved their dispersion in solution, and thus contributed to the formation of a more uniform passivation layer on the perovskite surface.

[0042] Using a 10cm×10cm large-area inverted perovskite module as the test object, it was divided into a control group (single PZDI passivation) and an experimental group (PZDI-TOPO synergistic passivation). A standard photovoltaic performance testing system was used to determine the module's current-voltage (JV) characteristic curve and key photovoltaic parameters. Figure 6 The photoelectric conversion efficiency of a 10cm×10cm module using a hybrid passivation strategy of PZDI and TOPO increased from 16.65% to 20.78% (inverted structure), and the open-circuit voltage V... oc While the current density J increased by 10.12%, the fill factor FF increased by 4.36%. sc It increased by 0.22 mA / cm 2 Therefore, the device efficiency has been greatly improved.

[0043] Using a hybrid passivation strategy combining PZDI and TOPO can improve the environmental stability of components. For example... Figure 7 As shown, the prepared area is 100 cm². 2The device, after 1000 hours of maximum power point tracking at 60°C and 50% relative humidity, still maintained 94% of its initial efficiency. In contrast, the device passivated by PZDI alone only maintained 70% of its initial efficiency after the same stability test. This demonstrates that the strategy of introducing TOPO into PZDI can improve the stability of large-area modules, which is of great significance for industrialization.

[0044] In one embodiment, the mass ratio of trioctylphosphine oxide to piperazine dihydroiodate is (2.5:1) to (4:1). This ratio range ensures that there are sufficient trioctylphosphine oxide molecules in the system to compete for hydrogen bonds with the amine protons in the piperazine dihydroiodate molecules, thereby maximally suppressing the self-aggregation tendency of piperazine dihydroiodate and promoting its uniform distribution. If the proportion of the second passivating agent is too low, it will not be enough to completely break the intermolecular hydrogen bond network of the first passivating agent, resulting in poor dispersion; if the proportion is too high, the excessive amount of the second passivating agent will affect the ideal coverage and function of the first passivating agent on the perovskite surface.

[0045] In one embodiment, the passivation layer solution further includes a first solvent in which various passivating agents are dissolved, wherein the first solvent is one or more of isopropanol, ethanol, methanol, acetonitrile, ethyl acetate, toluene, chlorobenzene, N,N-dimethylformamide, or dimethyl sulfoxide.

[0046] The first solvent of the synergistic passivator solution can be any polar or nonpolar solvent capable of dissolving the selected passivator and compatible with the perovskite layer, such as isopropanol, ethanol, methanol, acetonitrile, ethyl acetate, toluene, chlorobenzene, N,N-dimethylformamide, dimethyl sulfoxide, and their mixtures. First, the first solvent provides the necessary and stable liquid carrier for realizing the aforementioned synergistic passivation strategy, ensuring that the passivator molecules can be smoothly and uniformly transported to the perovskite surface. Second, by selecting from a variety of first solvents, the requirements of different film-forming processes on solution properties can be flexibly adapted, providing a basis for achieving uniform coating and controlling film morphology.

[0047] Furthermore, the concentration of the passivating agent, the ratio of two (or more) passivating agents, the coating speed, the coating environment (humidity, temperature), the post-annealing temperature and time, and other process parameters can all be adjusted within a wide range according to the specific material combination and process requirements. The adjustment and optimization of these parameters are all within the conventional experimental scope of this patented technical solution.

[0048] In one embodiment, a method for preparing a passivation layer on a perovskite surface utilizes the passivation layer solution from the aforementioned embodiment. The preparation method can also achieve precise control over the morphology, coverage, and stability of the passivation layer by actively and precisely regulating several key process variables during the passivation layer formation process, thereby optimizing device performance. Regulated variables include, but are not limited to, the overall concentration of the passivating agent in the solution and the film-forming process parameters for applying the passivation layer solution to the perovskite surface to form a solid film. Regulating the concentration of the passivating agent relates to the spacing and diffusion behavior of the passivating agent molecules in the solution, thus affecting the effective coverage thickness and molecular arrangement density of the passivation layer ultimately formed on the perovskite surface. Optimizing the film-forming process parameters allows for precise management of the solvent evaporation rate and the self-assembly process of the passivating agent molecules, providing a direct means of obtaining an ideal film morphology.

[0049] In one embodiment, a method for preparing a perovskite thin film includes the following steps: S100. Obtain the perovskite light-absorbing layer. This step provides the substrate for surface defect passivation.

[0050] S200. The passivation layer solution from the above embodiment is applied to the surface of the perovskite light-absorbing layer to form a passivation film. This step uses solution processing technology to uniformly deliver and cover the perovskite surface with a mixed system containing a first passivating agent and a second passivating agent, forming a passivation wet film.

[0051] S300: The passivation film is processed to form a passivation layer covering the surface of the perovskite light-absorbing layer. This processing step aims to promote solvent evaporation and drive the passivating agent molecules to complete directional arrangement, anchoring, and self-assembly on the perovskite surface, ultimately transforming into a stable solid passivation layer covering the surface of the perovskite light-absorbing layer.

[0052] This method features a simple process flow and is easily integrated into existing perovskite device fabrication sequences. The broad meaning of the "apply" operation in step S200 allows it to be compatible with various solution film deposition techniques. The "process" step in step S300 preserves flexibility for subsequent optimization of curing conditions based on different material systems. This method reliably transforms the compositional advantages of the synergistic passivation layer solution into a tangible, high-performance passivation layer structure on the perovskite film surface, thereby ensuring the optimization of the final device performance.

[0053] In one embodiment, the method for obtaining the perovskite light-absorbing layer of S100 is as follows: it is prepared by one of the following methods: slot coating, blade coating, spray coating, inkjet printing, screen printing, or roll-to-roll coating; and / or The method by which the passivation layer solution is applied to the surface of the perovskite light-absorbing layer in S200 is one of the following: slot coating, blade coating, spray coating, inkjet printing, screen printing, or roll-to-roll coating.

[0054] The synergistic passivation method described above is not only applicable to slot coating processes but also to other large-area, high-throughput solution-based fabrication processes, including but not limited to blade coating, spray coating, inkjet printing, screen printing, and roll-to-roll (R2R) coating. It effectively improves the problems of uneven defect distribution and poor passivation consistency in large-area perovskite films, making it suitable for manufacturing high-performance, high-stability perovskite modules. The passivating agent is not limited to spin coating; any of the aforementioned large-area compatible coating methods can also be used. This strategy is applicable to various perovskite solar cell device structures, including nip structures, pin structures, monolithic perovskite / silicon tandem cells, and all-perovskite tandem cells.

[0055] In one embodiment, processing the passivation film includes an annealing step at a temperature of 90°C to 120°C for 3 to 10 minutes. The lower limit of the temperature range (90°C) ensures sufficient thermal energy to effectively remove solvent molecules remaining in the passivation film, while promoting the diffusion, rearrangement, and stable bonding of the first and second passivating agent molecules to surface defect sites on the perovskite surface. The upper limit (120°C) aims to avoid excessive thermal stress that could adversely affect the crystal structure of the underlying perovskite light-absorbing layer or the already formed passivating agent molecule assemblies. Correspondingly, the 3 to 10-minute annealing time window provides sufficient time for the aforementioned thermally driven process, ensuring the reaction reaches completion and guaranteeing the efficiency of the production process.

[0056] The passivation layer solutions and the synergistic passivation strategies embodied in the above embodiments are not only applicable to lead-based perovskites (such as FAPbI3, MAPbI3, CsPbI3 and their mixed cation / halogen systems), but also applicable to other metal halide perovskite material systems, such as tin (Sn)-based perovskites, germanium (Ge)-based perovskites, and lead-tin (Pb-Sn) mixed perovskites, as long as they have surface and grain boundary defects that can be suppressed by molecular passivation strategies.

[0057] Furthermore, the synergistic passivation layer formed by the passivation layer solution can be used in combination with other interface modification layers, passivation layers, or device optimization techniques. For example, other types of passivation materials (such as polymers, metal oxide nanoparticles, low-dimensional perovskites, etc.) can be deposited on or under this synergistic passivation layer, or it can be combined with bulk passivation and grain boundary passivation strategies to form multiple passivation effects, further improving device performance and stability. This integrated solution also falls within the scope of application protected by this patent.

[0058] In one embodiment, an optoelectronic device includes a perovskite thin film prepared by the fabrication method described in the above embodiments. The high-quality, low-defect-density perovskite thin film prepared based on the fabrication method and synergistic passivation strategy described in the above embodiments can be used not only in solar cells but also extended to other optoelectronic device applications, such as perovskite light-emitting diodes (PeLEDs), perovskite photodetectors, and perovskite field-effect transistors.

[0059] Among them, solar cells include, but are not limited to, single-junction perovskite solar cells, perovskite / crystalline silicon tandem cells, and all-perovskite tandem cells, which have good process compatibility and scalability.

[0060] In one specific embodiment, the fabrication process of a perovskite solar cell includes the following steps: Picosecond lasers were used to scribing P1 lines on indium tin oxide transparent conductive glass to mark out non-conductive sub-cell regions.

[0061] The conductive glass substrate was cleaned in an ultrasonic cleaner using glass cleaning fluid, acetone, and isopropanol to remove impurities and residual organic matter from the glass surface.

[0062] The conductive glass is dried in an oven or blown dry with a nitrogen gun to remove residual organic solvents from the surface.

[0063] The surface of conductive glass is treated with a UVO ozone generator or a plasma cleaner to improve wettability.

[0064] Hole transport layer material was prepared by slit coating on a conductive glass substrate and then annealed.

[0065] Weigh the perovskite precursor solute powder and the additives / medications.

[0066] Perovskite raw materials and additives are dissolved in an organic solvent to prepare a perovskite precursor solution.

[0067] Hole transport layer was prepared by scraping and then annealed. Perovskite films were prepared on the hole transport layer using the slit coating method and then annealed.

[0068] Dynamic spin-coating passivation layer.

[0069] An electron transport layer and a hole blocking layer were deposited on a perovskite thin film using a vacuum thermal evaporation method.

[0070] Picosecond lasers are used to perform P2 scribing, and laser etching is used to etch other films above the conductive oxide.

[0071] Metal electrodes are deposited using a vacuum thermal evaporation method, and these metal electrodes are used to extract electrons.

[0072] Picosecond lasers are used to scribing lines in the P3 region to separate the sub-cells.

[0073] Use P4 scribing to clean the edges and remove any residual impurities from the P2 and P3 scribing lines.

[0074] Encapsulating adhesive is used to encapsulate the components to protect their structure and improve their stability.

[0075] In a more specific embodiment, the fabrication process of a perovskite solar cell includes the following steps: (1) A picosecond laser was used to scribing a 10×10 cm indium tin oxide transparent conductive glass with P1 lines. The bottom conductive oxide film layer was etched by laser to form independent conductive oxide substrates. The laser scribing frequency was 100 Hz, the energy was 48.5 μJ, the speed was 200 mm / s, and the scribing width was 20 μm.

[0076] (2) Ultrasonic cleaning of the glass substrate. The cleaning reagents used are, in order, a special cleaning solution for conductive glass, deionized water, and isopropanol. The conductive glass substrate must be completely immersed in the liquid, and each cleaning reagent should be used for 20±5 minutes.

[0077] (3) Take out the cleaned conductive glass substrate and dry it in a drying oven at 70°C for 24 hours.

[0078] (4) Remove the dried conductive glass substrate and transfer it to the UVO ozone generator for cleaning for 15 minutes.

[0079] (5) Remove the conductive glass substrate and transfer it to the electron beam evaporation system to deposit a nickel oxide thin film. The pressure of the evaporation system is 7 × 10⁻⁶. -4 Pa. A small flow of oxygen within the range of 15 standard cubic centimeters per minute was present during the evaporation process to improve the composition of the nickel oxide film. The substrate was kept at room temperature throughout the process, and the thickness of the nickel oxide was monitored by a crystal oscillator and a film thickness gauge. The deposition thickness was 26 nm.

[0080] (6) Prepare the hole transport layer solution by dissolving 1 mg of [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (i.e. Me-4PACz) in 1 mL of methanol:chloroform solvent (volume ratio 1:1), shaking thoroughly for 10 h, and then filtering.

[0081] (7) A hole transport layer was prepared by a blade coating method. The hole transport layer was coated in an air atmosphere with a relative humidity of 20-30% and a temperature of 25-30°C. The conductive glass substrate to be coated was placed on the blade coater, adsorbed and fixed, and the surface dust was removed by air blowing. 17 µL of the prepared hole transport layer solution was evenly dropped onto one side of the front end. The distance between the blade and the substrate was set to 1.35 mm, the blade forward speed was 12 mm / s, and the return speed was 15 mm / s. The blade was started, and the blade moved in a straight line from one end of the substrate to the other end at a uniform speed, coating a uniformly wetted film on the substrate.

[0082] (8) Transfer the conductive glass with the hole transport layer deposited to the hot stage and anneal it at 100°C for 10 minutes.

[0083] (9) Prepare a perovskite precursor solution in the cooling module. The perovskite precursor solution formulation is FA. 0.95 Cs 0.05 The PbI3 was prepared by dissolving a mixture of 21.1922 g of formamidine lead iodide (FAPbI3), 0.4676 g of cesium iodide (CsI), 2.1579 g of lead iodide (PbI2), 0.1215 g of methylamine chloride (MACl), and 0.2063 g of guanidine chloride (GACl) in a mixed solvent of 25 mL of N,N-dimethylformamide (DMF) and 5 mL of N-methylpyrrolidone (NMP) to prepare a perovskite precursor solution. After shaking thoroughly for 10 h, the solution was filtered.

[0084] (10) Perovskite layer was prepared using slit coating. The perovskite layer was coated in an air atmosphere with a relative humidity of 20-30% and a temperature of 30°C. First, the pretreated conductive glass substrate was fixed on the coating machine platform, and vacuum adsorption was turned on to ensure that the substrate was flat and adhered. After removing surface dust with a precision air gun, the distance between the slit die and the substrate was precisely controlled at 70 μm. The perovskite precursor solution was delivered to the slit of the die at a constant flow rate of 0.1 mm / s through a precision injection pump, and the coating platform moved linearly at a uniform speed of 2 mm / s. After starting the coating program, the die completed a uniform scanning motion along the substrate axis, forming a perovskite wet film with uniform thickness and no stripes on the substrate surface. Then, the perovskite wet film was crystallized by vacuum flash evaporation combined with thermal annealing. The coated substrate was quickly transferred to the vacuum flash evaporation device, and the chamber pressure was reduced to 10 Pa within 10 seconds and maintained for 20 seconds to form a pre-crystallized film through rapid solvent evaporation. Then, thermal annealing was performed. The sample was first pretreated on a 70°C hot stage for 1 minute, and then transferred to a 110°C hot stage for annealing for 5 minutes, finally obtaining a uniformly crystalline and completely covered perovskite light-absorbing layer.

[0085] (11) Prepare the passivation layer solution. Dissolve 9 mg of tri-n-octylphosphine oxide (TOPO) and 3 mg of piperazine dihydroiodide (PZDI) in 40 mL of isopropanol solvent, shake well for 10 h and then filter.

[0086] (12) A passivation layer was prepared by spin coating. The deposited perovskite substrate was fixed on the stage of a spin coater by vacuum adsorption, and its surface was cleaned by purging with nitrogen to remove adsorbed particles. Then, 1000 μL of passivation layer solution was uniformly added, and the spin coating parameters were set to 2500 rpm and the spin coating time was 30 seconds. After the spin coater was started, the solution spread and evaporated uniformly under the action of high-speed rotation, and finally a continuous and uniform passivation film was formed on the perovskite surface.

[0087] (13) Transfer the substrate with the passivation layer deposited to the hot stage and anneal at 100°C for 5 minutes.

[0088] (14) An electron transport layer was deposited using a vacuum thermal evaporation method. The equipment vacuum level was 2×10⁻⁶. -4 Pa. The electron transport layer material is C. 60 The evaporation current was 40 A, the deposition rate was 0.1 nm / s, and the deposition thickness was 30 nm.

[0089] (15) Hole-blocking layer material bath copper (BCP) was deposited using vacuum thermal evaporation, with a vacuum degree of 2×10⁻⁶. -4 Pa. The evaporation voltage was 2.2–3.5 V, the deposition rate was 0.02 nm / s, and the deposition thickness was 6.5 nm.

[0090] (16) Picosecond laser was used to perform P2 scribing, and the laser etched the other films above the conductive oxide. The laser scribing frequency was 50 Hz, the energy was 48.5 μJ, the speed was 200 mm / s, and the width of the scribed line was 100 μm.

[0091] (17) Copper electrodes were deposited using a vacuum thermal evaporation method. The vacuum degree of the vacuum thermal evaporation equipment was 2×10⁻⁶. -4 Pa. The deposition rate was 0.5 nm / s, and the deposition thickness was 100 nm.

[0092] (18) Picosecond laser was used to scribing lines in P3 to separate the sub-cells. The laser scribing frequency was 15 Hz, the energy was 48.5 μJ, the speed was 150 mm / s, and the width of the scribing line was 50 μm.

[0093] (19) Use P4 scribing to clean the edges and remove residual impurities from P2 and P3 scribing to avoid short circuits. The laser scribing frequency is 100 Hz, the energy is 20 μJ, the speed is 500 mm / s, and the width of the scribing line is 100 μm.

[0094] (20) The module is encapsulated using a thermal lamination method. A 1 cm wide butyl rubber ring is applied around the perimeter of the module, a polyolefin elastomer (POE) encapsulation film is placed on top, a cover glass is installed on top, and the module is placed in a thermal lamination apparatus with a temperature of 120°C and a vacuum degree of 1×10⁻⁶. -2 Pa for 30 minutes to allow the butyl rubber to fully melt and adhere tightly to the surrounding area, achieving a good sealing effect.

[0095] This invention discloses a synergistic passivation strategy suitable for large-area perovskite thin films. Its core lies in introducing a second passivating agent (such as a molecule containing a strong electronegative group) to form competitive hydrogen bonds with a first passivating agent (such as a molecule containing an amine group and a halide ion), effectively interrupting the self-aggregation behavior between the molecules of the first passivating agent, thereby achieving a uniform and dense monolayer distribution on the perovskite surface, and improving the uniformity of the passivation layer coverage and the repeatability of the process.

[0096] Furthermore, the second passivating agent not only has the ability to disrupt the intermolecular interactions of the first passivating agent, but also has the ability to address perovskite surface defects (especially uncoordinated Pb). 2+ It has a stronger coordination ability, thereby achieving a more thorough and stable passivation of defects, forming a dual functional mechanism of "dispersion + enhanced passivation".

[0097] In the description of this specification, the use of terms such as "Embodiment 1," "this embodiment," or "in one embodiment" indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example; moreover, the specific features, structures, materials, or characteristics described may be combined in any appropriate manner in one or more embodiments or examples.

[0098] In the description of this specification, the terms "connection," "installation," "fixing," "setting," and "having" are interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0099] In the description of this specification, relational terms such as “first” and “second” are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0100] The above description of the embodiments is intended to enable those skilled in the art to understand and apply the technology of this invention. Those skilled in the art can easily make various modifications to these examples and apply the general principles described herein to other embodiments without creative effort. Therefore, this invention is not limited to the above embodiments. Modifications in the following situations should be within the scope of protection of this invention: ① New technical solutions implemented based on the technical solution of this invention and combined with existing common knowledge, where the technical effects of the new technical solution do not exceed the technical effects of this invention; ② Equivalent substitutions of some features of the technical solution of this invention using known technology, resulting in the same technical effects as those of this invention; ③ Extendable technical solutions based on the technical solution of this invention, where the substantive content of the extended technical solution does not exceed the technical solution of this invention; ④ Equivalent transformations made using the content of this specification and drawings, directly or indirectly applied to other related technical fields.

Claims

1. A passivation layer solution, characterized in that, The present invention includes a variety of passivating agents, wherein the various passivating agents include at least a first passivating agent and a second passivating agent. The molecular structure of the first passivating agent includes electron-donating groups and electron-accepting groups that can form intermolecular hydrogen bonds. The molecular structure of the second passivating agent includes strongly electronegative atoms or groups. The first passivating agent is piperazine dihydroiodate, and the second passivating agent is trioctylphosphine oxide.

2. The passivation layer solution according to claim 1, characterized in that, The mass ratio of the trioctylphosphine oxide to the piperazine dihydroiodate is (2.5:1) to (4:1).

3. The passivation layer solution according to any one of claims 1-2, characterized in that, It also includes a first solvent in which various passivating agents are dissolved, wherein the first solvent is one or more of isopropanol, ethanol, methanol, acetonitrile, ethyl acetate, toluene, chlorobenzene, N,N-dimethylformamide or dimethyl sulfoxide.

4. A method for preparing a perovskite thin film, characterized in that, Includes the following steps: S100, Obtain the perovskite light-absorbing layer; S200: Apply the passivation layer solution as described in any one of claims 1 to 3 to the surface of the perovskite light-absorbing layer to form a passivation film; S300. The passivation film is processed to form a passivation layer covering the surface of the perovskite light-absorbing layer.

5. The preparation method according to claim 4, characterized in that, The perovskite light-absorbing layer of S100 is obtained by one of the following methods: slot coating, blade coating, spray coating, inkjet printing, screen printing, or roll-to-roll coating; and / or The method by which the passivation layer solution is applied to the surface of the perovskite light-absorbing layer in S200 is one of the following: slot coating, blade coating, spray coating, inkjet printing, screen printing, or roll-to-roll coating.

6. The preparation method according to claim 5, characterized in that, The process of treating the passivated film includes an annealing step, wherein the annealing temperature is 90°C to 120°C and the annealing time is 3 to 10 minutes.

7. An optoelectronic device, characterized in that, It comprises a perovskite thin film prepared by the preparation method according to any one of claims 4 to 6.

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