A high-transmission-efficiency perovskite thin film for near-space applications and its preparation process

Abstract

This invention provides a high-transmission-efficiency perovskite thin film for near-space applications and its preparation process, belonging to the field of perovskite thin film technology. The process includes the following steps: Step S1, preparing a precursor solution; Step S2, spin-coating a pretreated substrate with the precursor solution to obtain a perovskite master film; Step S3, preparing a modified perovskite master film; Step S4, performing low-temperature atomic layer deposition on the modified perovskite master film to obtain a high-transmission-efficiency perovskite thin film. This invention can improve the transmission efficiency of perovskite thin films while simultaneously enhancing film stability.

Description

Technical Field

[0001] This invention relates to the field of perovskite thin film technology, and more specifically to a high-transmission-efficiency perovskite thin film for near-space applications and its preparation process. Background Technology

[0002] Perovskite thin films have seen rapid development in fields such as solar cells, photoelectric detection, and light-emitting devices due to their advantages, including high absorption coefficients, long carrier diffusion lengths, solution-processability, and low-temperature fabrication. Current fabrication techniques often employ spin-coating with solvent-induced crystallization, optimizing crystallization kinetics through solvent engineering, composition engineering, and additive control. Simultaneously, interface / surface passivation and encapsulation barrier layers are used to reduce defect density, suppress non-radiative recombination, and improve environmental stability. As the application scenarios of perovskite thin films expand from ground-based environments to high-altitude platforms and near-space, these films not only need high charge transport efficiency and device output capabilities but also require long-term stability of their structural and electrical properties under more complex service environments.

[0003] Patent application CN116390609A discloses a method for preparing perovskite thin films. The method involves dissolving Cs salt, organic ammonium halide salt, lead halide, and thiophene methylamine ammonium salt in a first solvent, DMF / DMSO, to obtain a perovskite precursor solution. This perovskite precursor solution is then coated onto a substrate, and an antisolvent is added. After a first annealing treatment, a perovskite absorber layer is obtained. The thiophene methylamine ammonium salt is then dissolved in a second solvent, isopropanol / methanol / ethanol, to obtain a thiophene methylamine ammonium salt solution. This solution is coated onto the perovskite absorber layer, and after a second annealing treatment, the perovskite thin film is obtained. However, the perovskite thin film prepared by this method lacks sufficient control over the film morphology and grain size during crystallization, and exhibits a high defect state density, resulting in insufficient improvement in photoelectric performance and maintenance of long-term stability.

[0004] Therefore, there is a need to provide a perovskite thin film with high transmission efficiency for near-space applications and its preparation process to solve the problems existing in the prior art. Summary of the Invention

[0005] In view of this, the present invention provides a perovskite thin film with high transmission efficiency for near-space applications and its preparation process, which can improve the transmission efficiency of perovskite thin films while improving film stability.

[0006] To achieve the above objectives, the present invention provides a process for preparing high-transmission-efficiency perovskite thin films for near-space applications, comprising the following steps:

[0007] Step S1: Add lead iodide, lead bromide, formamidine iodide, formamidine bromide, cesium iodide, and guanidine iodide to a brown glass bottle in sequence, then add choline tartrate, octyl p-methoxycinnamate, and diethylene sulfone, followed by N,N-dimethylformamide and dimethyl sulfoxide. Heat and stir, cool, allow to stand to remove bubbles, filter, and obtain the precursor solution.

[0008] Step S2: The precursor solution is dropped onto the center of the pretreated substrate, then spin-coated and an antisolvent is added to obtain a perovskite wet film. The film is then subjected to low-pressure flash evaporation, segmented annealing, and natural cooling to room temperature to obtain the perovskite main film.

[0009] Step S3: Add glycerol to isopropanol and mix well to obtain solution A; dissolve p-fluorophenylethylamine iodine in isopropanol and mix well to obtain solution B; spin-coat solution A onto the surface of the perovskite host film, dry, then spin-coat solution B and anneal to obtain the modified perovskite host film.

[0010] Step S4: Low-temperature atomic layer deposition is performed on the modified perovskite master film. First, an alumina layer is deposited, followed by alternating deposition of alumina and silicon dioxide. After deposition, the film is naturally cooled to obtain a perovskite film with high transport efficiency.

[0011] In traditional one-step spin-coating systems, the precursor often exhibits "localized instantaneous supersaturation" under solvent impact, leading to problems such as uneven nucleation, wide grain size distribution, and high grain boundary density; simultaneously, uncoordinated Pb at grain boundaries / surfaces... 2+ Defects such as halogen vacancies are difficult to "occupy" in a long-term and stable manner, which leads to enhanced nonradiative recombination and ion migration, ultimately resulting in insufficient transport efficiency and decreased stability.

[0012] This scheme employs a multi-cation mixed halogen system consisting of PbI₂ (lead iodide), PbBr₂ (lead bromide), FAI (formamidine iodide), FABr (formamidine bromide), CsI (cesium iodide), and GAI (guanidine iodide). On one hand, FA serves as the main component to ensure the foundation of photoelectric performance; on the other hand, CsI... + with GA + The synergistic introduction of Cs improves lattice stability and modulates the grain boundary chemical environment. + It helps to improve crystal phase stability and reduce lattice dynamic distortion, thereby suppressing ion migration channels under electric / thermal stress; GA + With multiple hydrogen bond interaction sites, it tends to accumulate at grain boundaries / surfaces, stabilizing the structure near defects through hydrogen bonding / electrostatic interactions. This helps reduce grain boundary trap density and weaken grain boundary barriers, thereby improving effective transport across grains.

[0013] In strong ion precursor systems, many neutral organic molecules are prone to incompatibility or local enrichment, and if they are strong Lewis bases, they may also react with Pb. 2+Excessive complexation can disrupt crystallization kinetics and introduce uncontrollable intermediate phases; furthermore, the lack of ion anchoring often makes it difficult to maintain long-term fixation at grain boundary / surface defect sites. Tartrate choline also contains substances that can react with Pb. 2+ The interacting oxygen-containing group and the positively charged choline structure, wherein the oxygen-containing group can interact with uncoordinated Pb 2+ Defect sites generate weak coordination / hydrogen bonding, reducing Pb 2+ Related pitfalls; however, the positively charged choline structure can electrostatically compensate for the charge unevenness near halogen vacancies, making it easier for them to "occupy" and remain stable at grain boundaries / surfaces; therefore, tartrate choline can achieve defect passivation and grain boundary chemical stabilization without significantly disturbing the main crystal structure, thereby reducing nonradiative recombination and improving transgrain boundary transport continuity. Octyl methoxycinnamate has an ester group and a long alkyl chain, and its ester group can react with Pb. 2+ The coordination environment generates weak interactions, improving the local solvation environment, resulting in more uniform nucleation, more complete grain growth, and reduced pores and pinholes. The long alkyl chain imparts hydrophobicity, readily accumulating at grain boundaries / surfaces to form hydrophobic barriers, reducing water molecule adsorption and penetration along grain boundaries, decreasing water-induced halogen vacancy generation and enhanced ion migration, thus contributing to improved film stability. Diethylene sulfone possesses a strongly polar sulfone group and electron-withdrawing characteristics, favoring dipole / coordination interactions with defect-rich regions, thereby reducing uncoordinated Pb. 2+ Related trap states are generated, and the ion migration barrier at the grain boundary is increased, inhibiting halogen migration and ion accumulation; therefore, diethylene sulfone can achieve "migration suppression and trap reduction" at the grain boundary level.

[0014] The polyhydroxyl groups in glycerol can form hydrogen bonds / weak coordination at uncoordinated sites on the perovskite film surface, playing a primary passivation and wetting regulation role, resulting in more uniform subsequent organic ammonium salt coverage and reducing local exposure; for fluorophenylethylamine iodine... - It can specifically compensate for halogen vacancies; organic ammonium groups can stably "occupy" surface defect sites, reduce surface trap density, and inhibit surface recombination; fluorine substitution enhances hydrophobicity and chemical stability, thereby reducing performance degradation induced by surface water absorption and ion migration. Therefore, modification with glycerol and fluorophenylethylamine iodine transforms the perovskite film surface from a "high defect activity interface" to a "low recombination, low permeability interface," which is beneficial for simultaneously improving transport efficiency and stability.

[0015] First, an alumina layer is deposited on the modified perovskite master film as a transition layer, which preferentially fills the micropores on the surface, improves the continuity of subsequent alternating deposition layers, and has a certain passivation effect on surface defects. Then, by alternating deposition of alumina and silica, a multi-interface structure is formed, which can significantly extend the water and oxygen diffusion path and block pinhole penetration. At the same time, the multi-interface structure can also improve the ion translayer migration barrier, suppress halogen escape and bias voltage-induced ion accumulation, thereby improving the long-term stability of the perovskite film.

[0016] Preferably, in step S1, the precursor solution comprises the following components in parts by weight:

[0017] 360-410 parts lead iodide, 120-150 parts lead bromide, 35-50 parts formamidine iodide, 80-105 parts formamidine bromide, 30-45 parts cesium iodide, 12-25 parts guanidine iodide, 0.8-2.5 parts choline tartrate, 0.2-0.8 parts octyl p-methoxycinnamate, and 0.25-1.00 parts divinyl sulfone.

[0018] Preferably, in step S2, the preparation of the pretreated substrate includes the following steps:

[0019] The substrate is ultrasonically cleaned, dried with nitrogen, treated with UV-O3, spin-coated with SnO2 adhesive, and annealed to obtain a pretreated substrate.

[0020] After ultrasonic cleaning, nitrogen drying and UV-O3 treatment of the substrate, organic contaminants can be significantly removed and polar groups such as hydroxyl groups can be introduced on the substrate surface, improving surface energy and wettability, making it easier to form a dense, continuous and pinhole-free electron transport layer by subsequent SnO2 colloid spin coating.

[0021] Preferably, the spin coating speed is 2500-3500 rpm and the time is 20-40 s; the annealing temperature is 120-160℃ and the time is 20-35 min.

[0022] Preferably, in step S2, the spin coating is divided into two stages, wherein the spin coating speed of the first stage is 800-1500 rpm and the time is 5-15 s; the spin coating speed of the second stage is 3500-5500 rpm and the time is 20-40 s.

[0023] The first low-speed stage mainly achieves the spreading and leveling of the precursor solution; the second high-speed stage achieves morphological fixation and rapid drying.

[0024] Preferably, in step S2, the segmented annealing consists of the following steps: first, pre-annealing at 60-80℃ for 1-5 minutes, and then main annealing at 100-120℃ for 10-20 minutes.

[0025] Pre-annealing releases residual solvent and alleviates stress, while main annealing completes crystallization and promotes grain growth. This reduces grain boundary density and grain boundary barriers, decreases carrier scattering and recombination, and thus improves thin film transport efficiency.

[0026] Preferably, in step S2, the antisolvent is prepared by the following steps:

[0027] Octyl p-methoxycinnamate was dissolved in ethyl acetate and mixed to obtain an antisolvent.

[0028] The addition of pure ethyl acetate will rapidly draw away DMF / DMSO and instantly reduce its solubility. If the mixing is uneven, it can easily lead to uneven nucleation and pore formation. Octyl methoxycinnamate, as a hydrophobic organic solute, will change the local viscosity, surface tension and solute distribution behavior in the liquid film after addition, making the supersaturation more uniform, thus resulting in a more consistent nucleation density and more uniform grain size.

[0029] Preferably, in step S3, the spin coating speed of solution A is 2000-4000 rpm and the time is 10-30 s; the spin coating speed of solution B is 3000-5000 rpm and the time is 10-30 s; the annealing temperature is 80-110℃ and the time is 1-2 min.

[0030] Preferably, in step S4, the total thickness of the low-temperature atomic layer deposition is 43-56 nm.

[0031] To achieve the above objectives, the present invention also provides a perovskite thin film with high transmission efficiency for near-space applications prepared by the above-described preparation process of a perovskite thin film with high transmission efficiency for near-space applications.

[0032] The perovskite thin film with high transport efficiency prepared by the method of the present invention for near-space applications can improve the film's transport efficiency while simultaneously enhancing its stability.

[0033] The above-described technical solution of the present invention has at least the following beneficial effects:

[0034] 1. By introducing choline tartrate, octyl methoxycinnamate and diethylene sulfone into the precursor system, effective passivation of grain boundary / surface defects and suppression of ion migration can be achieved, resulting in a more dense, uniform perovskite film with a lower grain boundary barrier, thereby reducing recombination current and improving carrier transport efficiency.

[0035] 2. By using glycerol for primary passivation and forming a surface organic ammonium salt with p-fluorophenylethylamine iodine, the surface trap state density of the thin film can be significantly reduced and the surface hydrophobicity can be enhanced, thereby inhibiting surface recombination and the intrusion of external water and oxygen, and improving the operational stability of the device.

[0036] 3. By first depositing ultrathin alumina using low-temperature ALD followed by alternating layers of alumina and silica for encapsulation, an inorganic barrier layer with continuous coverage, low pinhole probability, and tortuous diffusion path can be formed. This significantly reduces water and oxygen permeation and ion escape, thereby improving the long-term stability of the perovskite film and achieving high-efficiency transport. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The described embodiments are some embodiments of the present invention, and all other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0038] Example 1

[0039] The substrate was ultrasonically cleaned, dried with nitrogen, treated with UV-O3 for 15 min, and then spin-coated with SnO2 adhesive at a speed of 3000 rpm for 30 s. Finally, it was annealed at 140℃ for 30 min to obtain the pretreated substrate.

[0040] 385 mg lead iodide, 135 mg lead bromide, 42 mg formamidine iodide, 93 mg formamidine bromide, 38 mg cesium iodide, and 18 mg guanidine iodide were added sequentially to a brown glass bottle. Then, 1.6 mg choline tartrate, 0.5 mg octyl p-methoxycinnamate, and 0.65 mg divinyl sulfone were added. Subsequently, 720 μL of N,N-dimethylformamide and 240 μL of dimethyl sulfoxide were added. The mixture was heated to 32 °C and stirred for 75 min. After cooling to room temperature, it was allowed to stand for 10 min to remove bubbles. Finally, it was filtered through a 0.22 μm polytetrafluoroethylene filter membrane to obtain the precursor solution.

[0041] Dissolve 4 mg of octyl p-methoxycinnamate in 1 mL of ethyl acetate and mix well to obtain the antisolvent.

[0042] The precursor solution was dropped onto the center of the pretreated substrate at a rate of 70 μL, followed by two-stage spin coating: the first stage was spin-coated at 1200 rpm for 10 s; the second stage was spin-coated at 4500 rpm for 30 s. 20 s after the start of the second stage spin coating, 175 μL of antisolvent was dropped onto the center of the spin coating at once, and spin coating continued until the end to obtain a perovskite wet film. The film was then subjected to low-pressure flash evaporation to remove the solvent at a pressure of 350 Pa for 1.5 min, followed by segmented annealing: pre-annealing at 70 °C for 4 min, followed by main annealing at 110 °C for 15 min, and then naturally cooled to room temperature to obtain the perovskite main film.

[0043] 0.1 mL of glycerol was added to 10 mL of isopropanol and mixed well to obtain solution A; 40 mg of p-fluorophenylethylamine iodine was dissolved in 10 mL of isopropanol and mixed well to obtain solution B; solution A was spin-coated onto the surface of the perovskite host film at a spin speed of 3000 rpm for 20 s, and then dried at 65 °C for 6 min. Then solution B was spin-coated at a spin speed of 4000 rpm for 20 s, and then annealed at 95 °C for 2 min to obtain the modified perovskite host film.

[0044] At 100℃, a modified perovskite master film was subjected to low-temperature atomic layer deposition. First, an alumina layer was deposited with a thickness of 2nm. Then, alumina and silicon dioxide were deposited alternately, with the thickness of a single alumina layer controlled at 3nm and the thickness of a single silicon dioxide layer controlled at 3nm, for a total thickness of 50nm. After deposition, the film was allowed to cool naturally to obtain a perovskite film with high transport efficiency.

[0045] Example 2

[0046] The substrate was ultrasonically cleaned, dried with nitrogen, treated with UV-O3 for 15 min, and then spin-coated with SnO2 adhesive at a speed of 3500 rpm for 20 s. Finally, it was annealed at 120℃ for 35 min to obtain the pretreated substrate.

[0047] 410 mg lead iodide, 150 mg lead bromide, 50 mg formamidine iodide, 105 mg formamidine bromide, 45 mg cesium iodide, and 25 mg guanidine iodide were added sequentially to a brown glass bottle. Then, 2.5 mg choline tartrate, 0.8 mg octyl p-methoxycinnamate, and 1 mg divinyl sulfone were added. Subsequently, 820 μL of N,N-dimethylformamide and 180 μL of dimethyl sulfoxide were added. The mixture was heated to 35 °C and stirred for 60 min. After cooling to room temperature, it was allowed to stand for 10 min to remove bubbles. Finally, it was filtered through a 0.22 μm polytetrafluoroethylene filter membrane to obtain the precursor solution.

[0048] Dissolve 5 mg of octyl p-methoxycinnamate in 1 mL of ethyl acetate and mix well to obtain the antisolvent.

[0049] The precursor solution was dropped onto the center of the pretreated substrate at a rate of 60 μL, followed by two-stage spin coating: the first stage was spin-coated at 1500 rpm for 5 s, and the second stage was spin-coated at 5500 rpm for 20 s. Ten s after the start of the second stage spin coating, 100 μL of antisolvent was dropped onto the center of the spin coating at once, and spin coating was continued until the end to obtain a perovskite wet film. The film was then subjected to low-pressure flash evaporation to remove the solvent at a pressure of 450 Pa for 1 min, followed by segmented annealing: pre-annealing at 60 °C for 5 min, followed by main annealing at 100 °C for 20 min, and then naturally cooled to room temperature to obtain the perovskite main film.

[0050] 0.2 mL of glycerol was added to 10 mL of isopropanol and mixed well to obtain solution A; 50 mg of p-fluorophenylethylamine iodine was dissolved in 10 mL of isopropanol and mixed well to obtain solution B; solution A was spin-coated onto the surface of the perovskite host film at a spin speed of 2000 rpm for 30 s, and then dried at 80 °C for 3 min. Then solution B was spin-coated at a spin speed of 3000 rpm for 30 s, and then annealed at 80 °C for 2 min to obtain the modified perovskite host film.

[0051] At 110℃, a modified perovskite master film was subjected to low-temperature atomic layer deposition. First, an alumina layer was deposited with a thickness of 2nm. Then, alumina and silicon dioxide were deposited alternately, with the thickness of a single alumina layer controlled at 2nm and the thickness of a single silicon dioxide layer controlled at 3nm, for a total thickness of 52nm. After deposition, the film was allowed to cool naturally to obtain a perovskite film with high transport efficiency.

[0052] Example 3

[0053] The substrate was ultrasonically cleaned, dried with nitrogen, treated with UV-O3 for 15 min, and then spin-coated with SnO2 adhesive at a speed of 2500 rpm for 40 s. Finally, it was annealed at 160℃ for 20 min to obtain the pretreated substrate.

[0054] 360 mg lead iodide, 120 mg lead bromide, 35 mg formamidine iodide, 80 mg formamidine bromide, 30 mg cesium iodide, and 12 mg guanidine iodide were added sequentially to a brown glass bottle. Then, 0.8 mg choline tartrate, 0.2 mg octyl p-methoxycinnamate, and 0.25 mg divinyl sulfone were added. Subsequently, 770 μL of N,N-dimethylformamide and 210 μL of dimethyl sulfoxide were added. The mixture was heated to 30 °C and stirred for 90 min. After cooling to room temperature, it was allowed to stand for 10 min to remove bubbles. Finally, it was filtered through a 0.22 μm polytetrafluoroethylene filter membrane to obtain the precursor solution.

[0055] Dissolve 3 mg of octyl p-methoxycinnamate in 1 mL of ethyl acetate and mix well to obtain the antisolvent.

[0056] The precursor solution was dropped onto the center of the pretreated substrate at a rate of 80 μL, followed by two-stage spin coating: the first stage was spin-coated at 800 rpm for 15 s; the second stage was spin-coated at 3500 rpm for 40 s. 25 s after the start of the second stage spin coating, 250 μL of antisolvent was dropped onto the center of the spin coating at once, and spin coating was continued until the end to obtain a perovskite wet film. The film was then subjected to low-pressure flash evaporation to remove the solvent at a pressure of 250 Pa for 2 min, followed by segmented annealing: pre-annealing at 80 °C for 3 min, followed by main annealing at 120 °C for 10 min, and then naturally cooled to room temperature to obtain the perovskite main film.

[0057] 0.03 mL of glycerol was added to 10 mL of isopropanol and mixed well to obtain solution A; 30 mg of p-fluorophenylethylamine iodine was dissolved in 10 mL of isopropanol and mixed well to obtain solution B; solution A was spin-coated onto the surface of the perovskite host film at a spin speed of 4000 rpm for 10 s, and then dried at 50 °C for 10 min. Then solution B was spin-coated at a spin speed of 5000 rpm for 10 s, and then annealed at 110 °C for 1 min to obtain the modified perovskite host film.

[0058] At 90℃, a modified perovskite master film was subjected to low-temperature atomic layer deposition. First, an alumina layer was deposited with a thickness of 3nm. Then, alumina and silicon dioxide were deposited alternately, with the thickness of a single alumina layer controlled at 2nm and the thickness of a single silicon dioxide layer controlled at 3nm, for a total thickness of 43nm. After deposition, the film was allowed to cool naturally to obtain a perovskite film with high transport efficiency.

[0059] Example 4

[0060] The substrate was ultrasonically cleaned, dried with nitrogen, treated with UV-O3 for 15 min, and then spin-coated with SnO2 adhesive at a speed of 3200 rpm for 25 s. Finally, it was annealed at 130℃ for 30 min to obtain the pretreated substrate.

[0061] 385 mg lead iodide, 135 mg lead bromide, 42 mg formamidine iodide, 93 mg formamidine bromide, 38 mg cesium iodide, and 18 mg guanidine iodide were added sequentially to a brown glass bottle. Then, 1.6 mg choline tartrate, 0.5 mg octyl p-methoxycinnamate, and 0.65 mg divinyl sulfone were added. Subsequently, 720 μL of N,N-dimethylformamide and 240 μL of dimethyl sulfoxide were added. The mixture was heated to 35 °C and stirred for 60 min. After cooling to room temperature, it was allowed to stand for 10 min to remove bubbles. Finally, it was filtered through a 0.22 μm polytetrafluoroethylene filter membrane to obtain the precursor solution.

[0062] Dissolve 6 mg of octyl p-methoxycinnamate in 1 mL of ethyl acetate and mix well to obtain the antisolvent.

[0063] The precursor solution was dropped onto the center of the pretreated substrate at a rate of 60 μL, followed by two-stage spin coating: the first stage was spin-coated at 1500 rpm for 5 s, and the second stage was spin-coated at 5500 rpm for 20 s. Ten s after the start of the second stage spin coating, 100 μL of antisolvent was dropped onto the center of the spin coating at once, and spin coating was continued until the end to obtain a perovskite wet film. The film was then subjected to low-pressure flash evaporation to remove the solvent at a pressure of 450 Pa for 1 min, followed by segmented annealing: pre-annealing at 60 °C for 5 min, followed by main annealing at 100 °C for 20 min, and then naturally cooled to room temperature to obtain the perovskite main film.

[0064] 0.1 mL of glycerol was added to 10 mL of isopropanol and mixed well to obtain solution A; 40 mg of p-fluorophenylethylamine iodine was dissolved in 10 mL of isopropanol and mixed well to obtain solution B; solution A was spin-coated onto the surface of the perovskite host film at a spin speed of 3000 rpm for 20 s, and then dried at 65 °C for 6 min. Then solution B was spin-coated at a spin speed of 4000 rpm for 20 s, and then annealed at 95 °C for 2 min to obtain the modified perovskite host film.

[0065] At 105℃, a modified perovskite master film was subjected to low-temperature atomic layer deposition. First, an alumina layer was deposited with a thickness of 2nm. Then, alumina and silicon dioxide were deposited alternately, with the thickness of a single alumina layer controlled at 3nm and the thickness of a single silicon dioxide layer controlled at 3nm, for a total thickness of 56nm. After deposition, the film was allowed to cool naturally to obtain a perovskite film with high transport efficiency.

[0066] Example 5

[0067] The substrate was ultrasonically cleaned, dried with nitrogen, treated with UV-O3 for 15 min, and then spin-coated with SnO2 adhesive at a speed of 2800 rpm for 35 s. Finally, it was annealed at 150℃ for 25 min to obtain the pretreated substrate.

[0068] 360 mg lead iodide, 120 mg lead bromide, 35 mg formamidine iodide, 80 mg formamidine bromide, 30 mg cesium iodide, and 12 mg guanidine iodide were added sequentially to a brown glass bottle. Then, 0.8 mg choline tartrate, 0.2 mg octyl p-methoxycinnamate, and 0.25 mg divinyl sulfone were added. Subsequently, 770 μL of N,N-dimethylformamide and 210 μL of dimethyl sulfoxide were added. The mixture was heated to 30 °C and stirred for 90 min. After cooling to room temperature, it was allowed to stand for 10 min to remove bubbles. Finally, it was filtered through a 0.22 μm polytetrafluoroethylene filter membrane to obtain the precursor solution.

[0069] Dissolve 4 mg of octyl p-methoxycinnamate in 1 mL of ethyl acetate and mix well to obtain the antisolvent.

[0070] The precursor solution was dropped onto the center of the pretreated substrate at a rate of 70 μL, followed by two-stage spin coating: the first stage was spin-coated at 1200 rpm for 10 s; the second stage was spin-coated at 4500 rpm for 30 s. 20 s after the start of the second stage spin coating, 175 μL of antisolvent was dropped onto the center of the spin coating at once, and spin coating continued until the end to obtain a perovskite wet film. The film was then subjected to low-pressure flash evaporation to remove the solvent at a pressure of 350 Pa for 1.5 min, followed by segmented annealing: pre-annealing at 70 °C for 4 min, followed by main annealing at 110 °C for 15 min, and then naturally cooled to room temperature to obtain the perovskite main film.

[0071] 0.03 mL of glycerol was added to 10 mL of isopropanol and mixed well to obtain solution A; 30 mg of p-fluorophenylethylamine iodine was dissolved in 10 mL of isopropanol and mixed well to obtain solution B; solution A was spin-coated onto the surface of the perovskite host film at a spin speed of 4000 rpm for 10 s, and then dried at 50 °C for 10 min. Then solution B was spin-coated at a spin speed of 5000 rpm for 10 s, and then annealed at 110 °C for 1 min to obtain the modified perovskite host film.

[0072] At 95℃, a modified perovskite master film was subjected to low-temperature atomic layer deposition. First, an alumina layer was deposited with a thickness of 3nm. Then, alumina and silicon dioxide were deposited alternately, with the thickness of a single alumina layer controlled at 2nm and the thickness of a single silicon dioxide layer controlled at 3nm, for a total thickness of 50nm. After deposition, the film was allowed to cool naturally to obtain a perovskite film with high transport efficiency.

[0073] Example 6

[0074] The substrate was ultrasonically cleaned, dried with nitrogen, treated with UV-O3 for 15 min, and then spin-coated with SnO2 adhesive at a speed of 3000 rpm for 30 s. Finally, it was annealed at 140℃ for 28 min to obtain the pretreated substrate.

[0075] 410 mg lead iodide, 150 mg lead bromide, 50 mg formamidine iodide, 105 mg formamidine bromide, 45 mg cesium iodide, and 25 mg guanidine iodide were added sequentially to a brown glass bottle. Then, 2.5 mg choline tartrate, 0.8 mg octyl p-methoxycinnamate, and 1 mg divinyl sulfone were added. Subsequently, 820 μL of N,N-dimethylformamide and 180 μL of dimethyl sulfoxide were added. The mixture was heated to 35 °C and stirred for 60 min. After cooling to room temperature, it was allowed to stand for 10 min to remove bubbles. Finally, it was filtered through a 0.22 μm polytetrafluoroethylene filter membrane to obtain the precursor solution.

[0076] Dissolve 5 mg of octyl p-methoxycinnamate in 1 mL of ethyl acetate and mix well to obtain the antisolvent.

[0077] The precursor solution was dropped onto the center of the pretreated substrate at a rate of 80 μL, followed by two-stage spin coating: the first stage was spin-coated at 800 rpm for 15 s; the second stage was spin-coated at 3500 rpm for 40 s. 25 s after the start of the second stage spin coating, 250 μL of antisolvent was dropped onto the center of the spin coating at once, and spin coating was continued until the end to obtain a perovskite wet film. The film was then subjected to low-pressure flash evaporation to remove the solvent at a pressure of 250 Pa for 2 min, followed by segmented annealing: pre-annealing at 80 °C for 3 min, followed by main annealing at 120 °C for 10 min, and then naturally cooled to room temperature to obtain the perovskite main film.

[0078] 0.15 mL of glycerol was added to 10 mL of isopropanol and mixed well to obtain solution A; 50 mg of p-fluorophenylethylamine iodine was dissolved in 10 mL of isopropanol and mixed well to obtain solution B; solution A was spin-coated onto the surface of the perovskite host film at a spin speed of 2000 rpm for 30 s, and then dried at 80 °C for 3 min. Then solution B was spin-coated at a spin speed of 3000 rpm for 30 s, and then annealed at 80 °C for 2 min to obtain the modified perovskite host film.

[0079] At 100℃, a modified perovskite master film was subjected to low-temperature atomic layer deposition. First, an alumina layer was deposited with a thickness of 2nm. Then, alumina and silicon dioxide were deposited alternately, with the thickness of a single alumina layer controlled at 3nm and the thickness of a single silicon dioxide layer controlled at 3nm, for a total thickness of 40nm. After deposition, the film was allowed to cool naturally to obtain a perovskite film with high transport efficiency.

[0080] The present invention also includes comparative examples and related experiments.

[0081] Comparative Example 1

[0082] The difference between Comparative Example 1 and Example 1 is that no hydrogen choline tartrate was added when preparing the precursor solution in Comparative Example 1. The other components and preparation methods are the same as in Example 1, and a perovskite thin film with high transmission efficiency for near-space applications is prepared.

[0083] Comparative Example 2

[0084] The difference between Comparative Example 2 and Example 1 is that the preparation of the modified perovskite master film in step S3 is skipped, while the other components and preparation methods are the same as in Example 1, and a perovskite thin film with high transmission efficiency for near-space applications is prepared.

[0085] Comparative Example 3

[0086] The difference between Comparative Example 3 and Example 1 is that only alumina is used for deposition in step S4, while the other components and preparation methods are the same as in Example 1, resulting in a perovskite thin film with high transport efficiency for near-space applications.

[0087] Performance testing

[0088] The perovskite thin films prepared in Examples 1-6 and Comparative Examples 1-3 were applied to devices, and photoelectric performance tests were conducted with a light intensity of 1000 W·m. -2The test results were Voc (open-circuit voltage), Jsc (short-circuit current density), FF (fill factor), and PCE (photovoltaic conversion efficiency). The performance stability of the perovskite thin film was tested according to GB / T 2423.24-2022 "Environmental Testing Part 2: Test Methods Test S: Guidelines for Simulated Ground Solar Radiation and Solar Radiation Testing and Climate Aging Testing". The PCE retention rate was used as the test result. The results are summarized in Table 1.

[0089] Table 1

[0090]

[0091] As shown in Table 1 above, compared with Example 1, Comparative Example 1 showed a decrease in both Voc and FF, and a decrease in PCE retention rate. This indicates that the lack of tartrate choline's defect occupancy and chemical stabilizing effect led to irradiation-induced defect activation and enhanced non-radiative recombination, resulting in a decrease in the transport efficiency and stability of the perovskite film. Compared with Example 1, Comparative Example 2 showed a significant decrease in all test results, indicating that modification with glycerol and p-fluorophenylethylamine iodide can promote surface defect passivation and enhance interface regulation, reduce non-radiative recombination and transport hindrance, and thus improve the transport efficiency and performance stability of the perovskite film. Compared with Example 1, Comparative Example 3 had similar initial photoelectric properties, but a significant decrease in PCE retention rate. This indicates that single alumina deposition is more prone to through-hole defects and barrier degradation under irradiation stress, leading to faster photoaging of the interface and film. Therefore, alternating deposition of alumina and silicon dioxide can improve the performance stability of the perovskite film.

[0092] The above are preferred embodiments of the present invention. Those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process for preparing high-transmission-efficiency perovskite thin films for near-space applications, characterized in that, Includes the following steps: Step S1: Add lead iodide, lead bromide, formamidine iodide, formamidine bromide, cesium iodide, and guanidine iodide to a brown glass bottle in sequence, then add choline tartrate, octyl p-methoxycinnamate, and diethylene sulfone, followed by N,N-dimethylformamide and dimethyl sulfoxide. Heat and stir, cool, allow to stand to remove bubbles, filter, and obtain the precursor solution. Step S2: The precursor solution is dropped onto the center of the pretreated substrate, then spin-coated and an antisolvent is added to obtain a perovskite wet film. The film is then subjected to low-pressure flash evaporation, segmented annealing, and natural cooling to room temperature to obtain the perovskite main film. Step S3: Add glycerol to isopropanol and mix well to obtain solution A; dissolve p-fluorophenylethylamine iodine in isopropanol and mix well to obtain solution B; Solution A was spin-coated onto the surface of the perovskite host film, dried, and then solution B was spin-coated and annealed to obtain the modified perovskite host film. Step S4: Low-temperature atomic layer deposition is performed on the modified perovskite master film. First, an aluminum oxide layer is deposited, followed by alternating deposition of aluminum oxide and silicon dioxide. After deposition, the film is naturally cooled to obtain a perovskite film with high transport efficiency.

2. The fabrication process of a high-transmission-efficiency perovskite thin film for near-space applications according to claim 1, characterized in that, In step S1, the precursor solution comprises the following components in parts by weight: 360-410 parts lead iodide, 120-150 parts lead bromide, 35-50 parts formamidine iodide, 80-105 parts formamidine bromide, 30-45 parts cesium iodide, 12-25 parts guanidine iodide, 0.8-2.5 parts choline tartrate, 0.2-0.8 parts octyl p-methoxycinnamate, and 0.25-1.00 parts divinyl sulfone.

3. The fabrication process of a high-transmission-efficiency perovskite thin film for near-space applications according to claim 1, characterized in that, In step S2, the preparation of the pretreated substrate includes the following steps: The substrate is ultrasonically cleaned, dried with nitrogen, treated with UV-O3, spin-coated with SnO2 adhesive, and annealed to obtain a pretreated substrate.

4. The fabrication process of a high-transmission-efficiency perovskite thin film for near-space applications according to claim 3, characterized in that, The spin coating speed is 2500-3500 rpm, and the time is 20-40 s; the annealing temperature is 120-160℃, and the time is 20-35 min.

5. The fabrication process of a high-transmission-efficiency perovskite thin film for near-space applications according to claim 1, characterized in that, In step S2, the spin coating is divided into two stages. The spin coating speed of the first stage is 800-1500 rpm and the time is 5-15 s. The spin coating speed of the second stage is 3500-5500 rpm and the time is 20-40 s.

6. The fabrication process of a high-transmission-efficiency perovskite thin film for near-space applications according to claim 1, characterized in that, In step S2, the segmented annealing consists of the following steps: first, pre-annealing at 60-80℃ for 1-5 minutes, and then main annealing at 100-120℃ for 10-20 minutes.

7. The fabrication process of a high-transmission-efficiency perovskite thin film for near-space applications according to claim 1, characterized in that, In step S2, the antisolvent is prepared by the following steps: Octyl p-methoxycinnamate was dissolved in ethyl acetate and mixed to obtain an antisolvent.

8. The fabrication process of a high-transmission-efficiency perovskite thin film for near-space applications according to claim 1, characterized in that, In step S3, the spin coating speed of solution A is 2000-4000 rpm and the time is 10-30 s; the spin coating speed of solution B is 3000-5000 rpm and the time is 10-30 s; the annealing temperature is 80-110℃ and the time is 1-2 min.

9. The fabrication process of a high-transmission-efficiency perovskite thin film for near-space applications according to claim 1, characterized in that, In step S4, the total thickness of the low-temperature atomic layer deposition is 43-56 nm.

10. A high-transmission-efficiency perovskite thin film for near-space applications, characterized in that, The perovskite thin film with high transmission efficiency for near-space applications is prepared using the preparation process described in any one of claims 1-9.

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