Large-area perovskite thin film vapor deposition preparation method based on three-dimensional laminar flow air field technology

Abstract

The invention provides a large-area perovskite thin film vapor deposition preparation method based on a three-dimensional laminar flow air field technology, and relates to the technical field of optical fibers, and the method comprises the steps: controlling the direction and flow velocity of a three-dimensional laminar flow air field, enabling precursor vapor to be uniformly conveyed to the surface of a substrate under the guidance of the laminar flow air field, and enabling the temperature of the substrate to be 80-150 DEG C; vapor deposition of the perovskite thin film is carried out on the surface of the substrate, and the large-area, uniform and good-crystallinity perovskite thin film is prepared by regulating and controlling the deposition temperature to be 80-150 DEG C, the wind field flow velocity to be 0.5-5 m / s and the precursor vapor concentration; and carrying out annealing treatment on the deposited perovskite thin film at 90-150 DEG C for 10-60 minutes so as to optimize the crystal structure and the photoelectric property of the perovskite thin film. According to the invention, the problem of non-uniform steam distribution in traditional vapor deposition is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of perovskite thin film technology, and in particular to a method for preparing large-area perovskite thin films by vapor deposition based on three-dimensional laminar flow wind field technology. Background Technology

[0002] Currently, the main methods for preparing perovskite thin films include solution printing (such as spin coating, inkjet printing, and blade coating) and vapor deposition (such as vacuum evaporation and chemical vapor deposition). Solution printing is widely used due to its simplicity and low cost. However, in large-area preparation, it is susceptible to uneven solvent evaporation rates and edge effects, leading to significant film thickness deviations (typically exceeding ±10%). Furthermore, surface defects such as pinholes and cracks are prone to occur, severely affecting the consistency of device performance. In addition, the organic solvents used in solution methods pose toxicity and safety concerns, limiting their application in large-scale production.

[0003] Vapor deposition, as a dry deposition technique, offers advantages such as high film purity and easily controllable composition, demonstrating greater potential for large-area film preparation. Traditional vapor deposition methods (such as vacuum evaporation) vaporize a precursor by heating it, then deposit it onto the substrate surface using molecular diffusion to form a film. However, this method struggles to achieve uniform distribution of the precursor vapor on large-area substrates. The main reasons are: firstly, the transport of precursor vapor within the chamber is easily affected by natural convection and temperature gradients, leading to significant differences in vapor concentration across different areas of the substrate; secondly, the lack of effective vapor guidance and flow rate control during deposition makes it difficult to precisely control the nucleation and growth process of the film, resulting in problems such as uneven crystal size and high surface roughness (typically exceeding 30 nm). Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing large-area perovskite thin films by vapor deposition based on three-dimensional laminar flow wind field technology, which effectively overcomes the problem of uneven vapor distribution in traditional vapor deposition.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A first aspect is a method for preparing large-area perovskite thin films by vapor deposition based on three-dimensional laminar flow wind field technology, the preparation method comprising:

[0007] A deposition chamber is provided, and a three-dimensional laminar flow wind field generator is installed inside the deposition chamber to form a uniform and stable three-dimensional laminar flow wind field inside the chamber;

[0008] The perovskite precursor material is placed in the deposition chamber. The perovskite precursor material contains PbI2 and CH3NH3I in a molar ratio of 1:1. It is then heated to 150-300℃ to vaporize it and form precursor vapor.

[0009] The direction and velocity of the three-dimensional laminar flow field are controlled so that the precursor vapor is uniformly transported to the substrate surface under the guidance of the laminar flow field, and the substrate temperature is 80-150℃.

[0010] Perovskite thin films are vapor-deposited on the substrate surface. By controlling the deposition temperature to 80-150℃, the wind flow rate to 0.5-5m / s, and the precursor vapor concentration, large-area, uniform, and well-crystallized perovskite thin films can be prepared.

[0011] The deposited perovskite film was annealed at 90-150℃ for 10-60 minutes to optimize its crystal structure and photoelectric properties.

[0012] The above-described solution of the present invention has at least the following beneficial effects:

[0013] By guiding precursor vapor through a precisely controlled three-dimensional laminar flow field, the problem of uneven vapor distribution in traditional vapor deposition is effectively overcome, enabling deposition in 30×30cm... 2 Perovskite films with uniform thickness, deviation <±5%, smooth surface, roughness <20nm, and good crystallinity are prepared on substrates with an area of ​​20 or more.

[0014] A staged deposition process (initial nucleation - substrate growth - surface planarization) combined with precise temperature and airflow control promoted the orderly growth and dense stacking of perovskite grains, reducing grain boundaries and defects. Subsequent stepped annealing further optimized the crystal structure, significantly improving the film crystallinity (XRD full width at half maximum < 0.1°), thereby effectively suppressing nonradiative recombination and enhancing the device's photoelectric conversion performance (open-circuit voltage increased by more than 5%, fill factor increased by more than 3%). Real-time monitoring of vapor concentration and substrate temperature, along with dynamic adjustment of airflow velocity and evaporation source temperature, ensured precise control of the entire deposition process parameters, significantly improving process stability and repeatability, and facilitating the acquisition of perovskite films with consistent performance. Detailed Implementation

[0015] Example 1

[0016] This embodiment aims to prepare a 30×30cm 2 The specific steps for producing large-area perovskite thin films are as follows:

[0017] Deposition chamber preparation: A deposition chamber equipped with a three-dimensional laminar flow wind field generator is selected. This generator includes six independently adjustable fan arrays located at the top of the chamber, as well as multiple adjustable airflow guide plates inside the chamber. Simultaneously, a temperature-controlled heating platform with an accuracy of ±1℃ is installed at the bottom of the chamber, and a real-time vapor concentration monitoring system (detection accuracy ±2%) is provided.

[0018] Precursor preparation and evaporation: PbI2 and CH3NH3I powders in a molar ratio of 1:1 were uniformly mixed. 10g of the mixed powder was placed in an independent ceramic evaporation source within the deposition chamber. A zoned temperature-controlled heating device was used to perform a stepped heating of the evaporation source: first, the temperature was uniformly increased from room temperature to 110℃ within 12 minutes, and held for 8 minutes to remove adsorbed moisture from the material; then, the temperature was uniformly increased to the target evaporation temperature of 200℃ within 8 minutes and maintained until the deposition process was completed, allowing the precursor material to fully vaporize and form uniform vapor. At this point, the vapor concentration was monitored and stabilized at 25mg / m³. 3 .

[0019] Three-dimensional laminar flow airflow control is achieved by generating a three-dimensional laminar flow airflow field through a fan array. The initial fan speed is adjusted to achieve an airflow velocity of 1.0 m / s. An airflow guide plate guides the laminar flow airflow direction to an incident angle of 30° with the substrate surface. A temperature-controlled heating stage is used to heat a 30×30cm substrate. 2 The substrate (ITO glass) temperature is precisely controlled at 100℃, with temperature fluctuations maintained within ±1.5℃ during deposition. A real-time monitoring system continuously monitors the vapor concentration distribution on the substrate surface, dynamically adjusting fan speed and airflow guide plate angle to ensure vapor concentration deviation is controlled within ±3%.

[0020] Vapor deposition process: The deposition process is divided into three stages:

[0021] Initial deposition stage: The wind flow velocity was controlled at 1.0 m / s, the deposition temperature was 100℃, and the deposition was carried out for 10 minutes to form a uniform nucleation layer on the substrate surface. At this time, the film thickness was about 50 nm.

[0022] Main deposition stage: Gradually increase the airflow velocity to 3 m / s, raise the deposition temperature to 130℃ and continue for 30 minutes, control the deposition rate at 3.5 nm / min, and increase the film thickness to about 105 nm, with a total thickness of 155 nm; in the final deposition stage, reduce the airflow velocity to 1.5 m / s, maintain the deposition temperature at 130℃ and continue for 10 minutes to complete the film surface planarization treatment, and the final film thickness is 350 nm.

[0023] Annealing treatment involves heating the deposited perovskite film from room temperature to the target annealing temperature of 120°C at a constant rate of 8°C / min under a nitrogen atmosphere; holding at 120°C for 30 minutes to allow for sufficient growth of perovskite grains and reconstruction of grain boundaries; and then slowly cooling to room temperature at a rate of 3°C / min after the holding period.

[0024] As a result, the obtained perovskite film has a thickness of 350 nm, a thickness deviation of ±3%, a surface roughness of 15 nm, and X-ray diffraction analysis shows that the film has good crystallinity and a full width at half maximum (FWHM) of 0.08°. Photoelectric testing shows that the device open-circuit voltage is improved by 6% and the fill factor is improved by 4%.

[0025] Example 2

[0026] This embodiment aims to prepare a 40×40cm 2 The specific steps for producing large-area perovskite thin films are as follows:

[0027] Preparation of the deposition chamber: The deposition chamber with the same structure as in Example 1 is used, equipped with 8 sets of top fan arrays, adjustable airflow guide plates, high-precision temperature control heating stage (temperature fluctuation ±1℃) and real-time vapor concentration monitoring system (detection accuracy ±2%).

[0028] Precursor preparation and evaporation: PbI2 and CH3NH3I powders in a 1:1 molar ratio were uniformly mixed, and 15g of the mixed powder was placed in an independent ceramic evaporation source. A stepped heating process was performed using a zone-controlled heating device: the temperature was uniformly increased from room temperature to 120℃ over 15 minutes, held for 10 minutes to remove moisture; then, the temperature was uniformly increased to the target evaporation temperature of 280℃ over 10 minutes and maintained until deposition was complete. At this point, the vapor concentration was monitored and stabilized at 40mg / m³. 3 .

[0029] Three-dimensional laminar flow airflow control: The initial wind speed of the fan array was set to 1.5 m / s, and the airflow direction was adjusted to a 40° incident angle with the substrate surface using airflow guide plates. A temperature-controlled heating table with a diameter of 40 × 40 cm was used. 2 The substrate (FTO glass) temperature is controlled at 140℃, with temperature fluctuations ≤±1℃ during deposition. A real-time monitoring system dynamically adjusts fan speed and guide plate angle to ensure vapor concentration deviation ≤±4%.

[0030] Vapor deposition process: The deposition process is divided into three stages:

[0031] Initial deposition stage: wind speed 1.5 m / s, deposition temperature 140℃, lasting 15 minutes, forming a nucleation layer with a film thickness of about 60 nm.

[0032] Main deposition stage: The wind flow velocity is gradually increased to 4 m / s, the deposition temperature is maintained at 140℃ for 40 minutes, the deposition rate is controlled at 4.5 nm / min, the film thickness increases to about 180 nm, and the total thickness reaches 240 nm.

[0033] Final deposition stage: The wind flow velocity was reduced to 2 m / s, the deposition temperature was 140℃, and the deposition time was 15 minutes to complete the surface smoothing. The final film thickness was 750 nm.

[0034] Annealing: In a nitrogen atmosphere, the film was heated from room temperature to 140°C at a heating rate of 10°C / min; held at 140°C for 45 minutes; and then cooled to room temperature at a cooling rate of 5°C / min.

[0035] Results: The prepared perovskite film had a thickness of 750 nm, a thickness deviation of ±4%, a surface roughness of 18 nm, and X-ray diffraction analysis showed a full width at half maximum (FWHM) of 0.09°, indicating good crystallinity. Photoelectric testing showed that the device open-circuit voltage was increased by 7% and the fill factor was increased by 5%.

[0036] Example 3

[0037] This embodiment focuses on the preparation of a 35×35cm ... 2 The specific preparation process for the perovskite thin film is as follows:

[0038] Deposition chamber configuration: The deposition chamber utilizes a built-in three-dimensional laminar flow wind field generator, which includes seven independently adjustable top fan arrays and six angle-adjustable airflow guide plates installed within the chamber. The bottom of the chamber is equipped with a heating platform with a temperature control accuracy of ±0.8℃, and also features a real-time vapor concentration monitoring system with a detection error controllable within ±1.5%.

[0039] Precursor treatment and vaporization: PbI2 and CH3NH3I powders were weighed at a 1:1 molar ratio, thoroughly mixed, and 12g was placed in the quartz evaporation source of the deposition chamber. A stepped heating method was implemented using a zoned temperature control heating device: first, the temperature was uniformly increased from room temperature to 105℃ over 13 minutes, and held for 7 minutes to remove adsorbed water from the material; then, the temperature was uniformly increased to the target evaporation temperature of 240℃ over 7 minutes and maintained until deposition was complete. At this point, the precursor vapor concentration was monitored and stabilized at 32 mg / m³. 3 .

[0040] Three-dimensional laminar flow control: A three-dimensional laminar flow field is generated by a fan array, with an initial wind speed set at 0.8 m / s. The airflow guide vanes are adjusted to ensure the precursor vapor covers the substrate at a 25° angle to the substrate surface. A temperature-controlled heating stage is used to heat a 35×35cm substrate. 2The substrate (flexible PET substrate) temperature is precisely controlled at 90℃, with temperature fluctuations consistently below ±1℃ during the deposition process. A real-time monitoring system continuously tracks vapor concentration distribution and dynamically adjusts fan speed and guide plate angle to ensure that the vapor concentration deviation on the substrate surface does not exceed ±2.5%.

[0041] Vapor deposition stage: The deposition process proceeds in three stages:

[0042] Initial deposition stage: The wind flow velocity is maintained at 0.8 m / s, the deposition temperature is 90℃, and the deposition time is 8 minutes to form a uniform nucleation layer on the substrate surface. At this time, the film thickness is about 40 nm.

[0043] Main deposition stage: The wind flow velocity was gradually increased to 2.5 m / s, the deposition temperature was raised to 125℃ and held for 25 minutes, the deposition rate was controlled at 3 nm / min, the film thickness increased to about 75 nm, and the total thickness reached 115 nm.

[0044] Final deposition stage: Reduce the wind flow rate to 1.2 m / s, maintain the deposition temperature at 125℃ for 8 minutes to complete the thin film surface planarization process, and the final thin film thickness is 500 nm.

[0045] Annealing optimization treatment: The deposited perovskite film was heated from room temperature to 110°C at a heating rate of 6°C / min under nitrogen atmosphere protection; it was held at 110°C for 25 minutes to promote perovskite grain growth and grain boundary reconstruction; after the holding period, it was slowly cooled to room temperature at a cooling rate of 2.5°C / min.

[0046] Performance results: The prepared perovskite film has a thickness of 500 nm, a thickness deviation of ±2.8%, and a surface roughness of 12 nm. X-ray diffraction analysis shows that the film has a full width at half maximum (FWHM) of 0.07° and excellent crystallinity. Photoelectric testing shows that the device open-circuit voltage is improved by 5.5% and the fill factor is improved by 3.5%.

[0047] Example 4

[0048] This embodiment aims to prepare a 50×50cm 2 The specific steps for producing large-area perovskite thin films are as follows:

[0049] Deposition chamber preparation: The deposition chamber is equipped with a top fan array of 9 sets, and the chamber contains 8 airflow guide plates with adjustable angles. The temperature control accuracy of the bottom temperature-controlled heating stage is ±0.5℃, and it is equipped with a high-sensitivity real-time vapor concentration monitoring system (detection accuracy ±1%).

[0050] Precursor preparation and evaporation: PbI2 and CH3NH3I powders in a 1:1 molar ratio were uniformly mixed, and 20g of the mixed powder was placed in a ceramic evaporation source. A stepped heating process was performed using a zone-controlled heating device: the temperature was uniformly increased from room temperature to 115℃ over 14 minutes, held for 9 minutes to remove moisture; then, the temperature was uniformly increased to the target evaporation temperature of 260℃ over 9 minutes and maintained until deposition was complete. At this point, the vapor concentration was monitored and stabilized at 45mg / m³. 3 .

[0051] Three-dimensional laminar flow airflow control: The initial wind speed of the fan array was set to 1.2 m / s, and the airflow direction was adjusted to a 35° incident angle with the substrate surface using airflow guide plates. A temperature-controlled heating table with a diameter of 50 × 50 cm was used. 2 The substrate (glass substrate) temperature is controlled at 130℃, with temperature fluctuations during deposition ≤ ±0.8℃. A real-time monitoring system dynamically adjusts fan speed and guide plate angle to ensure vapor concentration deviation ≤ ±3%.

[0052] Vapor deposition process: The deposition process is divided into three stages:

[0053] Initial deposition stage: wind speed 1.2 m / s, deposition temperature 130℃, lasting 12 minutes, forming a nucleation layer with a film thickness of about 55 nm.

[0054] Main deposition stage: The wind flow velocity is gradually increased to 3.5 m / s, the deposition temperature is maintained at 130℃ for 35 minutes, the deposition rate is controlled at 4 nm / min, the film thickness increases to about 140 nm, and the total thickness reaches 195 nm.

[0055] Final deposition stage: The wind flow velocity was reduced to 1.8 m / s, the deposition temperature was 130℃, and the deposition time was 12 minutes to complete surface smoothing. The final film thickness was 700 nm.

[0056] Annealing: In a nitrogen atmosphere, the film was heated from room temperature to 130°C at a heating rate of 9°C / min; held at 130°C for 40 minutes; and then cooled to room temperature at a cooling rate of 4°C / min.

[0057] Performance results: The prepared perovskite film has a thickness of 700 nm, a thickness deviation of ±3.5%, and a surface roughness of 16 nm. X-ray diffraction analysis shows a full width at half maximum (FWHM) of 0.085°, indicating good crystallinity. Photoelectric testing shows that the device open-circuit voltage is improved by 6.5%, and the fill factor is improved by 4.5%.

[0058] Example 5

[0059] This embodiment aims to prepare a 32×32cm... 2 The specific preparation steps for the perovskite thin film are as follows:

[0060] Deposition chamber preparation: A deposition chamber equipped with a top-mounted array of 6 independently adjustable fans is used, and 5 angle-adjustable airflow guide plates are installed inside the chamber. The temperature control accuracy of the temperature-controlled heating stage at the bottom of the chamber is ±1℃, and it is also equipped with a real-time vapor concentration monitoring system with a detection accuracy of ±2%.

[0061] Precursor treatment and vaporization: PbI2 and CH3NH3I powders were weighed at a 1:1 molar ratio, thoroughly mixed, and 11g was placed in the ceramic evaporation source of the deposition chamber. A stepped heating process was performed using a zoned temperature-controlled heating device: first, the temperature was uniformly increased from room temperature to 108℃ over 11 minutes, and held for 6 minutes to remove adsorbed moisture from the material; then, the temperature was uniformly increased to the target evaporation temperature of 220℃ over 6 minutes and maintained until deposition was complete. At this point, the precursor vapor concentration was monitored and stabilized at 28 mg / m³. 3 .

[0062] Three-dimensional laminar flow airflow control: A three-dimensional laminar flow airflow is generated through a fan array, with the initial wind speed set at 0.7 m / s. The airflow guide vanes are adjusted to ensure the precursor vapor covers the substrate at a 20° angle of incidence. A temperature-controlled heating stage is used to heat a 32×32cm substrate. 2 The substrate (ITO / PET flexible substrate) temperature is precisely controlled at 85℃, with temperature fluctuations maintained within ±1.2℃ during deposition. A real-time monitoring system continuously monitors the vapor concentration distribution and dynamically adjusts the fan speed and guide plate angle to ensure that the vapor concentration deviation on the substrate surface does not exceed ±3%.

[0063] Vapor deposition process: The deposition process is divided into three stages:

[0064] Initial deposition stage: The wind flow velocity is maintained at 0.7 m / s, the deposition temperature is 85℃, and the deposition time is 7 minutes to form a uniform nucleation layer on the substrate surface. At this time, the film thickness is about 35 nm.

[0065] Main deposition stage: The wind flow velocity was gradually increased to 2.2 m / s, the deposition temperature was raised to 122℃ and held for 22 minutes, the deposition rate was controlled at 2.8 nm / min, the film thickness increased to about 61.6 nm, and the total thickness reached 96.6 nm.

[0066] Final deposition stage: The wind flow velocity was reduced to 1.1 m / s, the deposition temperature was maintained at 122℃ for 7 minutes, and the film surface was smoothed. The final film thickness was 420 nm.

[0067] Annealing treatment: The deposited perovskite film was heated from room temperature to 100°C at a heating rate of 5.5°C / min under nitrogen atmosphere protection; it was held at 100°C for 20 minutes to promote perovskite grain growth and grain boundary reconstruction; after holding, it was slowly cooled to room temperature at a cooling rate of 2.2°C / min.

[0068] Performance results: The prepared perovskite film has a thickness of 420 nm, a thickness deviation of ±3.2%, and a surface roughness of 13 nm. X-ray diffraction analysis shows that the film has a full width at half maximum (FWHM) of 0.075° and good crystallinity. Photoelectric testing shows that the device open-circuit voltage is improved by 5.2% and the fill factor is improved by 3.2%.

[0069] Example 6

[0070] This embodiment focuses on the preparation of a 45×45cm ... 2 The specific process for producing large-area perovskite thin films is as follows:

[0071] Deposition chamber configuration: The deposition chamber features a built-in array of 8 top fans and 7 adjustable airflow guide plates. The bottom temperature-controlled heating stage has a temperature control accuracy of ±0.7℃ and is equipped with a high-sensitivity real-time vapor concentration monitoring system (detection accuracy ±1.5%).

[0072] Precursor preparation and evaporation: PbI2 and CH3NH3I powders in a 1:1 molar ratio were uniformly mixed, and 18g of the mixed powder was placed in a quartz evaporation source. A stepped heating method was implemented using a zoned temperature-controlled heating device: the temperature was uniformly increased from room temperature to 112℃ within 14 minutes, held for 8 minutes to remove moisture; then, the temperature was uniformly increased to the target evaporation temperature of 270℃ within 8 minutes and maintained until deposition was complete. At this point, the vapor concentration was monitored and stabilized at 42mg / m³. 3 .

[0073] Three-dimensional laminar flow airflow control: The initial wind speed of the fan array is set to 1.3 m / s, and the airflow direction is adjusted to an incident angle of 38° with the substrate surface through the airflow guide plate. A temperature-controlled heating table of 45×45 cm... 2 The substrate (FTO glass substrate) temperature was controlled at 135℃, with temperature fluctuations during deposition ≤ ±0.9℃. A real-time monitoring system dynamically adjusted fan speed and guide plate angle to ensure vapor concentration deviation ≤ ±3.5%.

[0074] Vapor deposition stage: The deposition process proceeds in three stages:

[0075] Initial deposition stage: wind speed 1.3 m / s, deposition temperature 135℃, lasting 13 minutes, forming a nucleation layer with a film thickness of about 60 nm.

[0076] Main deposition stage: The wind flow velocity was gradually increased to 3.8 m / s, the deposition temperature was maintained at 135℃ for 32 minutes, the deposition rate was controlled at 4.2 nm / min, the film thickness increased to about 134.4 nm, and the total thickness reached 194.4 nm.

[0077] Final deposition stage: The wind flow velocity was reduced to 1.7 m / s, the deposition temperature was 135℃, and the deposition time was 13 minutes to complete the surface smoothing. The final film thickness was 680 nm.

[0078] Annealing optimization treatment: In a nitrogen atmosphere, the film was heated from room temperature to 135°C at a heating rate of 8.5°C / min; held at 135°C for 35 minutes; and then cooled to room temperature at a cooling rate of 3.8°C / min.

[0079] Performance results: The prepared perovskite film has a thickness of 680 nm, a thickness deviation of ±3.8%, and a surface roughness of 17 nm. X-ray diffraction analysis shows a full width at half maximum (FWHM) of 0.088°, indicating excellent crystallinity. Photoelectric testing shows that the device open-circuit voltage is improved by 6.2%, and the fill factor is improved by 4.2%.

[0080] Comparative Example 1

[0081] This comparative example uses the same deposition chamber and materials as Example 1, but does not use a three-dimensional laminar flow wind field generator. The specific steps are as follows:

[0082] Deposition chamber preparation: The same deposition chamber as in Example 1 was used, but the top fan array and airflow guide plates were turned off, relying solely on natural convection for precursor vapor transport. The temperature-controlled heating stage below the substrate remained accurate to ±1°C, and the real-time vapor concentration monitoring system was retained.

[0083] Precursor preparation and evaporation: The process was identical to Example 1. 10 g of a 1:1 molar ratio mixture of PbI₂ and CH₃NH₃I powder was placed in a ceramic evaporation source, and the temperature was gradually increased to 200°C until the vapor concentration stabilized at 25 mg / m³. 3 .

[0084] Vapor transport and substrate control: The three-dimensional laminar flow wind field control is eliminated; precursor vapor diffuses to the substrate surface via natural convection. A 30×30cm substrate is selected. 2 The ITO glass was deposited at a temperature controlled at 100℃, with temperature fluctuations of ±1.5℃ during the deposition process. Due to the lack of active wind field control, the real-time vapor concentration monitoring system only recorded data and could not make dynamic adjustments; the measured deviation of the vapor concentration on the substrate surface was ±12%.

[0085] Vapor deposition process: The wind speed was not controlled in stages during the deposition process (no active wind speed regulation), and the deposition temperature was kept at 100°C for 50 minutes (consistent with the total deposition time in Example 1).

[0086] Annealing treatment: exactly the same as in Example 1, the temperature was increased to 120°C at 8°C / min in a nitrogen atmosphere, held for 30 minutes, and then cooled to room temperature at 3°C / min.

[0087] Results: The obtained perovskite film thickness was 350 nm, but the thickness deviation reached ±15%, and the surface roughness increased to 45 nm. X-ray diffraction analysis showed a full width at half maximum (FWHM) of 0.15°, indicating a significant decrease in crystallinity. Photoelectric testing showed that the device open-circuit voltage only increased by 2%, and the fill factor increased by 1%, which was far lower than the performance indicators of Example 1.

[0088] Comparative Example 2

[0089] This comparative example uses the same parameter settings as Example 3, but changes the heating method for precursor evaporation. The specific steps are as follows:

[0090] Deposition chamber configuration: completely consistent with Example 3, including 7 sets of fan arrays, 6 airflow guide plates, heating stage with ±0.8℃ accuracy and vapor concentration monitoring system.

[0091] Precursor preparation and evaporation: 12g of a 1:1 molar ratio mixture of PbI2 and CH3NH3I powder was placed in a quartz evaporation source. However, instead of a stepped heating method, the temperature was directly increased from room temperature to the target evaporation temperature of 240℃ at a rate of 20℃ / min, without a 105℃ holding-up dehydration step. The total heating time was approximately 12 minutes (consistent with the stepped heating time in Example 3), and the temperature was maintained at 240℃ until deposition was complete. Due to the lack of dehydration and the excessively rapid heating, the precursor vapor concentration fluctuated significantly, ranging from 18-38 mg / m³ in actual measurements. 3 Fluctuations within a certain range.

[0092] Three-dimensional laminar flow wind field control: exactly the same as in Example 3, initial wind speed 0.8 m / s, incident angle 25°, substrate (35×35cm) 2 (Flexible PET substrate) Temperature 90℃, temperature fluctuation ±1℃, real-time monitoring system dynamically adjusts to ensure vapor concentration deviation ±2.5%.

[0093] Vapor deposition stage: The deposition parameters are consistent with those of the three-stage deposition stage in Example 3, with an initial flow rate of 0.8 m / s (8 minutes), a main flow rate of 2.5 m / s (25 minutes), and a final flow rate of 1.2 m / s (8 minutes). The deposition temperature is adjusted according to the stage.

[0094] Annealing optimization treatment: exactly the same as in Example 3, the temperature was increased to 110°C at 6°C / min, held for 25 minutes, and then cooled at 2.5°C / min.

[0095] Results: The prepared perovskite film had a thickness of 500 nm, but the thickness deviation increased to ±8%, and the surface roughness reached 28 nm. X-ray diffraction analysis showed a full width at half maximum (FWHM) of 0.13°. Due to the moisture content and vapor concentration fluctuations in the precursor, there were many pinhole defects in the film. Photoelectric testing showed that the open-circuit voltage of the device increased by 3%, the fill factor increased by 2%, and the performance was significantly lower than that of Example 3.

[0096] Comparative Example 3

[0097] This comparative example uses the same equipment and materials as Example 5, but the deposition process does not control the wind speed and temperature in stages. The specific steps are as follows:

[0098] Preparation of the deposition chamber: completely consistent with Example 5, including 6 sets of fan arrays, 5 guide plates, ±1℃ precision heating stage and vapor concentration monitoring system.

[0099] Precursor treatment and vaporization: exactly the same as in Example 5, 11g of mixed powder was heated to 220°C in a stepped manner, and the vapor concentration was stabilized at 28mg / m³. 3 .

[0100] Three-dimensional laminar flow wind field control: The initial wind speed was set to 1.5 m / s (the average wind speed of the three stages in Example 5). The wind speed was not adjusted during the deposition process. The air inflow angle was 20°. The substrate was 32 × 32 cm. 2 The temperature of the ITO / PET substrate was kept at 100°C (the midpoint of the three-stage temperatures in Example 5), with temperature fluctuations of ±1.2°C. A real-time monitoring system ensured that the vapor concentration deviation was ±3%.

[0101] Vapor deposition process: Uncontrolled in stages, with a constant wind speed of 1.5 m / s and a temperature of 100 °C for 42 minutes (consistent with the total deposition time in Example 5).

[0102] Annealing treatment: exactly the same as in Example 5, the temperature is increased to 100°C at 5.5°C / min, held for 20 minutes, and then cooled at 2.2°C / min.

[0103] Results: The obtained perovskite film thickness was 420 nm, but the thickness deviation reached ±9%, and the surface roughness was 32 nm. X-ray diffraction analysis showed a full width at half maximum (FWHM) of 0.12°. This was attributed to uneven nucleation density caused by excessive wind speed during the nucleation stage and insufficient temperature during the main growth stage affecting grain development. Photoelectric testing showed that the device open-circuit voltage was increased by 3.5%, and the fill factor was increased by 2.5%, but the performance was lower than the optimized results of Example 5.

[0104] Examples 1 to 6, based on three-dimensional laminar flow wind field technology, demonstrate significant advantages in large-area perovskite thin film vapor deposition preparation methods compared to Comparative Examples 1 to 3, in terms of film uniformity, crystal quality, photoelectric properties, and process stability, as detailed below:

[0105] Regarding film thickness uniformity, Examples 1 to 6, through precise control of the three-dimensional laminar flow wind field, combined with a three-stage deposition process and real-time vapor concentration monitoring and dynamic adjustment, achieved film thickness deviations within ±3.8%, with Example 3 exhibiting the lowest deviation at only ±2.8%. In contrast, Comparative Example 1, lacking a three-dimensional laminar flow wind field and relying solely on natural convection for precursor vapor transport, suffered from uneven vapor distribution on the substrate surface, resulting in a thickness deviation as high as ±15%. Comparative Example 2, without step-by-step heating and dehydration, experienced large fluctuations in precursor vapor concentration, increasing the thickness deviation to ±8%. Comparative Example 3, due to the lack of staged wind speed and temperature control during the deposition process, resulted in a mismatch between nucleation and growth conditions, leading to a thickness deviation of ±9%. The uniformity advantages of these examples lay a crucial foundation for the large-scale fabrication of large-area perovskite devices.

[0106] Regarding surface quality and crystallinity, the films prepared in Examples 1 to 6 all had surface roughness less than 20 nm, with Example 3 exhibiting a surface roughness as low as 12 nm. Furthermore, the X-ray diffraction full width at half maximum (FWHM) was controlled below 0.09°, demonstrating excellent crystallinity. This is attributed to the uniform nucleation of the precursor guided by a three-dimensional laminar flow wind field, the removal of moisture through step-by-step heating to avoid defects, and the precise control of grain growth through staged deposition. In contrast, Comparative Example 1, lacking active wind field control, resulted in uneven vapor diffusion, leading to a surface roughness of 45 nm and a FWHM of 0.15°. Comparative Example 2, due to fluctuations in precursor moisture content and vapor concentration, exhibited pinhole defects, resulting in a surface roughness of 28 nm and a FWHM of 0.13°. Comparative Example 3, due to unoptimized deposition stages, suffered from uneven nucleation density and poor grain development, resulting in a surface roughness of 32 nm and a FWHM of 0.12°. The high crystallinity of these examples effectively reduced grain boundary defects and improved the structural stability of the films.

[0107] Regarding the improvement in optoelectronic performance, after annealing, Examples 1 to 6 all showed an increase in open-circuit voltage of over 5% and a fill factor of over 3%, with Example 4 showing an increase in open-circuit voltage of 7% and a fill factor of 5%. This is because the uniform thin film structure, high crystallinity, and optimized crystal structure reduced carrier recombination centers, enhancing charge transport efficiency. In contrast, Comparative Example 1, due to poor thin film uniformity and numerous crystal defects, only saw an increase in open-circuit voltage of 2% and a fill factor of 1%; Comparative Example 2, affected by moisture and concentration fluctuations, saw an increase in open-circuit voltage of 3% and a fill factor of 2%; Comparative Example 3, due to the lack of staged optimization of deposition conditions, showed an improvement in optoelectronic performance of only 3.5% and 2.5%, both significantly lower than the levels of the Examples. The optoelectronic performance advantages of the Examples directly improve the energy conversion efficiency and long-term stability of perovskite devices.

[0108] Regarding process stability and reliability, Examples 1 to 6, through the synergistic effect of a three-dimensional laminar flow wind field generator, zoned temperature control heating, and real-time monitoring and feedback systems, achieved precise control over the entire process from precursor preparation to thin film deposition and annealing, ensuring the stability and reliability of different batches and substrates of different sizes (30×30cm). 2 Up to 50×50cm 2 The consistency of film performance was demonstrated in Comparative Example 1, which relied on natural convection and exhibited poor process repeatability; Comparative Example 2, lacking a dehydration step, resulted in the precursor easily absorbing moisture and deteriorating, affecting long-term production stability; and Comparative Example 3, with its single deposition parameters, struggled to adapt to the needs of different growth stages, leading to a low process tolerance. The process stability of these examples provides a reliable guarantee for the industrial-scale production of perovskite thin films.

[0109] In summary, Examples 1 to 6, through innovative designs such as three-dimensional laminar flow wind field technology, stepped heating, staged deposition, and precise temperature control, comprehensively solved the problems of poor uniformity, numerous crystallization defects, limited performance improvement, and unstable process existing in the comparative examples, significantly improving the quality and performance of large-area perovskite films, and have important practical application value.

[0110] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles 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 method for preparing large-area perovskite thin films by vapor deposition based on three-dimensional laminar flow wind field technology, characterized in that, The preparation method includes: A deposition chamber is provided, and a three-dimensional laminar flow wind field generator is installed inside the deposition chamber to form a uniform and stable three-dimensional laminar flow wind field inside the chamber; The perovskite precursor material is placed in the deposition chamber. The perovskite precursor material contains PbI2 and CH3NH3I in a molar ratio of 1:

1. It is then heated to 150-300℃ to vaporize it and form precursor vapor. The direction and velocity of the three-dimensional laminar flow field are controlled so that the precursor vapor is uniformly transported to the substrate surface under the guidance of the laminar flow field, and the substrate temperature is 80-150℃. Perovskite thin films are vapor-deposited on the substrate surface. By controlling the deposition temperature to 80-150℃, the wind flow rate to 0.5-5m / s, and the precursor vapor concentration, large-area, uniform, and well-crystallized perovskite thin films can be prepared. The deposited perovskite film was annealed at 90-150℃ for 10-60 minutes to optimize its crystal structure and photoelectric properties.

2. The method for preparing large-area perovskite thin films by vapor deposition based on three-dimensional laminar flow wind field technology according to claim 1, characterized in that, The flow velocity of the three-dimensional laminar flow field is controlled within the range of 0.5-5 m / s.

3. The method for preparing large-area perovskite thin films by vapor deposition based on three-dimensional laminar flow wind field technology according to claim 2, characterized in that, A perovskite precursor material, comprising PbI₂ and CH₃NH₃I in a molar ratio of 1:1, is placed in the deposition chamber and vaporized by heating to 150-300°C to form precursor vapor, comprising: PbI2 and CH3NH3I powders with a molar ratio of 1:1 were uniformly mixed and placed in an independent evaporation source within the deposition chamber. A zoned temperature-controlled heating device is used to raise the temperature of the evaporation source in a stepwise manner. The temperature is raised from room temperature to 100-120°C at a uniform rate within 10-15 minutes, and held for 5-10 minutes to remove the moisture adsorbed by the material. Then, the temperature is raised to the target evaporation temperature of 150-300°C at a uniform rate within 5-10 minutes, and maintained at this temperature until the deposition process is completed, so that the precursor material is fully vaporized to form uniform vapor.

4. The method for preparing large-area perovskite thin films by vapor deposition based on three-dimensional laminar flow wind field technology according to claim 3, characterized in that, Controlling the direction and velocity of the three-dimensional laminar flow field to uniformly transport the precursor vapor to the substrate surface under the guidance of the laminar flow field, wherein the substrate temperature is 80-150℃, includes: The three-dimensional laminar flow field is generated by multiple independently adjustable fan arrays located at the top of the deposition chamber, and the wind speed of the fan arrays is adjustable in the range of 0.5-5m / s. The direction of the laminar flow field is guided by the airflow guide plate set in the deposition chamber, so that the precursor vapor can be uniformly covered to the substrate surface at an incident angle of 15-45° with the substrate surface. The temperature of the substrate is precisely controlled within the range of 80-150℃ by a temperature-controlled heating stage located below the substrate, and the temperature fluctuation is kept less than ±2℃ during the deposition process. A real-time monitoring system is used to monitor the vapor concentration distribution on the substrate surface, and the fan speed and airflow guide plate angle are dynamically adjusted according to the monitoring results to ensure that the precursor vapor is uniformly distributed on the substrate surface and the concentration deviation is controlled within ±5%.

5. The method for preparing large-area perovskite thin films by vapor deposition based on three-dimensional laminar flow wind field technology according to claim 4, characterized in that, The thickness of the perovskite film is 300-800 nm.

6. The method for preparing large-area perovskite thin films by vapor deposition based on three-dimensional laminar flow wind field technology according to claim 5, characterized in that, Perovskite thin films are vapor-deposited on the substrate surface. By controlling the deposition temperature to 80-150℃, the airflow velocity to 0.5-5m / s, and the precursor vapor concentration, large-area, uniform, and well-crystallized perovskite thin films are prepared, including: The deposition process is divided into three stages: the initial deposition stage controls the wind flow velocity to be 0.5-1.5 m / s and the deposition temperature to be 80-100℃, lasting for 5-15 minutes, to form a uniform nucleation layer; During the main deposition stage, the wind flow velocity is gradually increased to 2-4 m / s, the deposition temperature is raised to 120-150℃ and maintained for 20-40 minutes, and the deposition rate is controlled at 2-5 nm / min to achieve the main growth of the thin film. In the final deposition stage, the wind speed is reduced to 1-2 m / s, the deposition temperature is maintained at 120-150℃ for 5-15 minutes, and the surface smoothing treatment of the film is completed. By dynamically adjusting the evaporation source temperature (150-300℃) and the airflow velocity (0.5-5m / s) based on the real-time monitoring system feedback of vapor concentration distribution, the precursor vapor concentration is controlled at 10-50 mg / m³. 3 Within the range, ensure it is within 30×30cm 2 Perovskite films with a thickness of 300-800 nm, a thickness deviation of less than ±5%, and a surface roughness of less than 20 nm were obtained on the above large-area substrates.

7. The method for preparing large-area perovskite thin films by vapor deposition based on three-dimensional laminar flow wind field technology according to claim 6, characterized in that, The deposited perovskite film was annealed at 90-150℃ for 10-60 minutes to optimize its crystal structure and photoelectric properties, including: The deposited perovskite film was heated from room temperature to the target annealing temperature of 90-150℃ at a constant rate of 5-10℃ / min under a nitrogen atmosphere. The perovskite grains are held at the target annealing temperature for 10-60 minutes to allow for full growth and grain boundary reconstruction, resulting in a dense crystal structure. After the heat preservation is completed, the film is slowly cooled to room temperature at a cooling rate of 2-5℃ / min to reduce film defects caused by thermal stress. X-ray diffraction analysis confirmed that the crystallinity of the film was improved after annealing, the full width at half maximum (FWHM) was reduced to below 0.1°, and photoelectric testing showed that the open-circuit voltage of the device was increased by more than 5% and the fill factor was increased by more than 3%.