Method for regulating and controlling crystallization of perovskite thin film based on surface laser annealing and preparation method of perovskite photovoltaic module

Abstract

The invention relates to a method for regulating and controlling crystallization of a perovskite thin film based on surface laser annealing and a preparation method of a perovskite photovoltaic module, and the surface laser annealing comprises the steps: constructing an infrared temperature measurement system in annealing equipment to monitor the surface temperature of the perovskite thin film in real time, and carrying out the closed-loop control of the output power of a surface laser; in annealing equipment, a preheating stage and a main annealing stage are executed through a surface laser, and optionally, a post-processing stage can be further added to prepare the perovskite thin film. Compared with the traditional heating stage annealing and line scanning laser annealing process, the method has the advantages that surface laser annealing is more uniform, local instantaneous heating is realized through high-energy dense surface laser within millisecond-second time, a solvent can be rapidly evaporated through rapid temperature rise, synchronous crystallization of a perovskite precursor is promoted, an independent precipitation time window of PbI2 is reduced, and the yield of PbI2 is improved. Therefore, the performance of the device is improved, and the high-efficiency perovskite solar cell module can be prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cells. Specifically, it relates to a method for regulating the crystallization of perovskite thin films based on surface laser annealing and a method for preparing perovskite photovoltaic modules. Background Art

[0002] Traditional annealing processes for perovskite thin films mainly rely on hot plate annealing, which promotes the crystallization of perovskite precursors by uniformly heating the substrate. For example, the Chinese patent "A method for preparing a perovskite solar cell" with the publication number CN 119072206 A in the prior art uses conventional hot plate annealing treatment.

[0003] However, this process has at least the following problems:

[0004] 1. Low process efficiency: The annealing treatment time requires dozens of minutes or even hours, with high energy consumption and difficulty in matching high-speed production lines;

[0005] 2. Insufficient crystallization control: Rapid evaporation of the solvent at high temperatures easily leads to uneven grain sizes and many pinhole defects, thereby reducing the film density;

[0006] 3. Restriction of flexible substrates: Flexible substrates (such as PET) are easily damaged in a high-temperature environment (>150°C), thus restricting the application scenarios.

[0007] Based on the above problems, those skilled in the art have adopted laser annealing. For example, the Chinese patent "A method for preparing a perovskite light-absorbing layer" with the publication number CN119384200 A in the prior art uses laser annealing treatment.

[0008] Laser annealing treatment mainly locally instantaneously heats the film surface (in the microsecond to millisecond range) through a high-energy laser beam, and can precisely control the energy distribution and action time.

[0009] However, existing laser annealing technologies still face at least the following challenges: the problem of uneven photo-thermal coupling: the problem of local overheating or under-burning of the film caused by differences in laser energy absorption; the problem of poor large-area uniformity: the low scanning efficiency of traditional point or line lasers, which easily causes grain boundary misalignment problems. Summary of the Invention

[0010] The present invention provides a method for regulating the crystallization of perovskite thin films based on surface laser annealing and a method for preparing perovskite photovoltaic modules to solve or alleviate the technical problems raised in the above background art.

[0011] The first aspect of the present invention provides a method for regulating the crystallization of perovskite thin films based on surface laser annealing, comprising the following steps:

[0012] Prepare a perovskite wet film on a substrate;

[0013] Adopt a vacuum flash evaporation process to assist in the formation of the perovskite wet film;

[0014] Construct an infrared temperature measurement system in the annealing equipment to be able to monitor the surface temperature distribution of the film in real time;

[0015] In the annealing equipment, perform the following annealing process through a surface laser to obtain a perovskite film:

[0016] Preheating stage, the surface laser outputs low-power infrared-band laser to preheat the film, with a power density of 0.1 - 10 W / cm 2 , and the irradiation time is 0.1 - 60 s;

[0017] Main annealing stage, the surface laser outputs high-power infrared-band laser to irradiate the film, with a power density of 10 - 100 W / cm 2 , and the irradiation time is 0.1 - 60 s;

[0018] And optionally, it may further include,

[0019] Post-treatment stage, the surface laser outputs low-power infrared-band laser to perform secondary annealing on the film, with a power density of 0.1 - 10 W / cm 2 , and the irradiation time is 0.1 - 60 s.

[0020] Preferably, during the preheating stage: control the substrate temperature to 80 - 120 °C.

[0021] Preferably, during the main annealing stage: if the infrared temperature measurement system detects that the temperature of a certain part of the film exceeds the critical value, immediately reduce the laser power to inhibit the precipitation of PbI2.

[0022] Preferably, dynamically feedback the surface temperature of the film through the infrared temperature measurement system, and adjust the laser power in combination with the PID algorithm to control the temperature fluctuation range within ±2 °C.

[0023] Furthermore, the infrared temperature measurement system uses a high-precision infrared thermal imager.

[0024] Preferably, the spot size of the laser output by the surface laser is not less than the size of the substrate.

[0025] Furthermore, the spot size range of the laser output by the surface laser is 1×1 cm 2 ~240×240 cm 2 .

[0026] In a second aspect, the present invention provides a method for preparing a perovskite photovoltaic module, including the following steps:

[0027] Provide an ITO glass substrate, use laser scribing P1 on the substrate and then clean it;

[0028] Prepare a hole transport layer on a substrate;

[0029] Coat a SAM layer on the hole transport layer and perform annealing treatment;

[0030] Coat a perovskite precursor solution on the SAM layer, and quickly transfer it into a vacuum chamber. Evacuate to 10 Pa and keep it for 30 s to obtain a perovskite wet film. Assist the formation of the perovskite wet film by using a vacuum flash evaporation process;

[0031] Anneal the wet film after flash evaporation according to the method described in the first aspect to obtain a perovskite film;

[0032] The subsequent processes include evaporating a C 60 layer, preparing a SnO2 layer, P2 scribing, preparing a metal electrode, P3 scribing and edge cleaning, and finally attaching a bus bar to complete the preparation of the perovskite photovoltaic module.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) Compared with the traditional hot plate annealing process, the surface laser annealing process adopted by the present invention greatly shortens the annealing time. The laser wavelength is accurately matched with the perovskite absorption peak, and the photothermal conversion efficiency exceeds 90%. While reducing energy waste, it can also inhibit the redistribution of impurities. Moreover, the laser energy only acts on the surface of the perovskite film, and the substrate temperature can be controlled at 80 - 120 °C (while the traditional hot plate annealing process will heat the whole substrate to 150 - 200 °C), thereby avoiding thermal deformation of flexible substrates (such as PET). In addition, this surface laser annealing process can quickly heat up and cool down the film to form ultra-fine grains (500 - 800 nm), reduce the grain boundary density, and further reduce the defect density, significantly improving the efficiency of photovoltaic devices.

[0035] (2) Differentiated annealing mode. Large-area uniform coverage: Use surface laser to cover the entire annealing area (such as the substrate size) at one time, eliminating the need for mechanical movement of point-by-point / line scanning, and breaking through the spatial limitation of the existing laser annealing spot mode; Closed-loop real-time regulation: Dynamically feedback the surface temperature of the film through an infrared temperature measurement system, and adjust the laser power in combination with the PID algorithm to control the temperature fluctuation within ±2 °C, avoiding the decomposition of perovskite caused by local overheating.

[0036] (3) Critical threshold protection: Set the critical temperature for PbI2 precipitation (such as 150 °C). When the temperature exceeds the limit, the working power of the surface laser can be immediately reduced to ensure the perovskite phase purity. Description of the Drawings

[0037] Figure 1 is a schematic diagram of the mapping relationship between temperature and laser power established through calibration experiments;

[0038] Figure 2 Figure showing the surface morphology comparison of perovskite thin films prepared in Example 1, Comparative Example 1, and Comparative Example 2;

[0039] Figure 3 Figure showing the crystal structure comparison of perovskite thin films prepared in Example 1, Comparative Example 1, and Comparative Example 2;

[0040] Figure 4 Figure showing the J-V curve and comparison of various photovoltaic parameters of perovskite solar cells prepared in Example 1, Comparative Example 1, and Comparative Example 2;

[0041] Figure 5 Figure showing the surface morphology comparison of perovskite thin films prepared in Example 2 and Comparative Example 3;

[0042] Figure 6 Figure showing the crystal structure comparison of perovskite thin films prepared in Example 2 and Comparative Example 3;

[0043] Figure 7 Figure showing the surface morphology comparison of perovskite thin films prepared in Example 3 and Comparative Example 4;

[0044] Figure 8 Figure showing the crystal structure comparison of perovskite thin films prepared in Example 3 and Comparative Example 4. Detailed implementation manners

[0045] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0046] An embodiment of the present invention provides a method for regulating the crystallization of perovskite thin films based on surface laser annealing. This method includes: preparing a perovskite wet film on a substrate, then using a vacuum flash evaporation process to assist the formation of the perovskite wet film, constructing an infrared temperature measurement system in an annealing device to be able to monitor the surface temperature distribution of the thin film in real time, and finally performing the annealing process in the annealing device through a surface laser in the following several stages to obtain a perovskite thin film.

[0047] The above annealing process includes two stages: a preheating stage, where the thin film is preheated by outputting low-power infrared-band laser through the surface laser, with a power density of 0.1 - 10 W / cm 2 , and the irradiation time is 0.1 - 60 s. This stage can promote the diffusion of the wet film forming precursor and reduce thermal stress; and a main annealing stage, where the thin film is irradiated by outputting high-power infrared-band laser through the surface laser, with a power density of 10 - 100 W / cm 2, the irradiation time is 0.1 - 60 s. In this stage, the perovskite absorption peak is matched to achieve efficient photothermal conversion and drive directional crystallization.

[0048] Alternatively, the above annealing process may include three stages: a preheating stage, where the film is preheated by outputting low-power infrared-band laser from a surface laser, with a power density of 0.1 - 10 W / cm 2 , the irradiation time is 0.1 - 60 s. This stage can promote the diffusion of the wet film forming precursor and reduce thermal stress; and a main annealing stage, where the film is irradiated with high-power infrared-band laser output from a surface laser, with a power density of 10 - 100 W / cm 2 , the irradiation time is 0.1 - 60 s. In this stage, the perovskite absorption peak is matched to achieve efficient photothermal conversion and drive directional crystallization; a post-treatment stage, where the film is secondarily annealed by outputting low-power infrared-band laser from a surface laser, with a power density of 0.1 - 10 W / cm 2 , the irradiation time is 0.1 - 60 s. This stage is to secondarily anneal the film to further eliminate grain boundary stress and reduce the defect density of the perovskite film.

[0049] In some embodiments, when performing the preheating stage, the substrate temperature is controlled within the range of 80 - 120 °C, which can avoid thermal deformation of the flexible substrate (such as PET) and prevent local overheating of the substrate.

[0050] It should be noted that during the main annealing stage, if the infrared temperature measurement system detects that the local temperature of a certain part of the film exceeds the critical value (such as 150 °C), the laser power is immediately reduced to inhibit the precipitation of PbI2, thereby ensuring the perovskite phase purity.

[0051] In some embodiments, the infrared temperature measurement system uses a high-precision infrared thermal imager (temperature measurement accuracy ±1 °C). The surface temperature of the film is dynamically fed back through the infrared temperature measurement system, and the laser power is adjusted in combination with the PID algorithm to control the temperature fluctuation range within ±2 °C. The mapping relationship between temperature and laser power can be established through a calibration experiment to ensure a small temperature fluctuation range. Refer to Figure 1 It can be seen that when the power of the surface laser is large, the heating rate of the film surface is fast, and when the power is reduced, the temperature also decreases accordingly.

[0052] It should be noted that during the annealing process, the spot size of the laser output by the surface laser will not actually be smaller than the size of the substrate, so as to ensure that the irradiation spot can completely cover the film on the substrate at one time. For example, when the size of the substrate is 30 cm * 30 cm, the spot of the laser output by the surface laser should be at least larger than 30 * 30 cm 2 , the spot size range of the laser output by the surface laser is 1 × 1 cm 2 ~240 × 240 cm2 , adapted to the size of the substrate.

[0053] In some embodiments, during the preheating stage or the post-treatment stage of the annealing process, the power density of the surface laser can be 0.1 W / cm 2 , 1 W / cm 2 , 2 W / cm 2 , 3 W / cm 2 , 4 W / cm 2 , 5 W / cm 2 , 6 W / cm 2 , 7 W / cm 2 , 8 W / cm 2 , 9 W / cm 2 or 10 W / cm 2 ; during the main annealing stage of the annealing process, the power density of the surface laser can be 10 W / cm 2 , 20 W / cm 2 , 30 W / cm 2 , 40 W / cm 2 , 50 W / cm 2 , 60 W / cm 2 , 70 W / cm 2 , 80 W / cm 2 , 90 W / cm 2 or 100 W / cm 2 , but not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0054] In some embodiments, the laser irradiation time during the preheating stage, the main annealing stage, and the post-treatment stage of the annealing process can be 0.1 s, 5 s, 10 s, 20 s, 30 s, 40 s, 50 s, or 60 s, but not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0055] The above surface laser annealing process solves the problems of low efficiency, poor uniformity, and thermal damage of the traditional hot plate annealing process, as well as the insufficient process stability and weak large-area adaptability of the line scan laser annealing through innovations such as infrared closed-loop temperature control, surface laser spot homogenization, and second-level rapid processing, and has significant technological breakthroughs in the field of perovskite photovoltaics.

[0056] A certain embodiment of the present invention also provides a method for preparing a perovskite photovoltaic module, which is characterized by including the following steps:

[0057] Provide an ITO glass substrate, use laser scribing P1 on the substrate and then clean it;

[0058] Prepare a hole transport layer on the substrate;

[0059] A SAM layer is coated on the hole transport layer and annealed;

[0060] A perovskite precursor solution is coated on the SAM layer and quickly transferred into a vacuum chamber. The vacuum is pumped to 10 Pa and maintained for 30 s to obtain a perovskite wet film. The vacuum flash evaporation process is used to assist the formation of the perovskite wet film;

[0061] According to the above method, the wet film after flash evaporation is annealed to obtain a perovskite film;

[0062] The subsequent process includes conventional evaporation of the C 60 layer, preparation of the SnO2 layer, P2 scribing, preparation of the metal electrode, P3 scribing and edge cleaning, and finally a bus bar is attached to complete the preparation of the perovskite photovoltaic module.

[0063] The numerical ranges described in the present invention include not only the above-listed point values, but also any point values between the above numerical ranges that are not listed. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the ranges.

[0064] Next, the present invention will provide specific examples and comparative examples to further illustrate the beneficial effects of the technical solutions of the present invention.

[0065] Example 1:

[0066] In this example, a large-area perovskite wet film is prepared by the slit coating vacuum method, and a high-efficiency solar photovoltaic module is prepared using the surface laser annealing process. The specific steps for preparing the module are as follows:

[0067] (1) After laser scribing P1 on ITO glass with a size of 30 cm × 30 cm, it is placed in a cleaning machine and cleaned;

[0068] (2) A hole transport layer of NiOx is prepared on 30 cm × 30 cm ITO using a magnetron sputtering device;

[0069] (3) A SAM layer is coated on the NiOx substrate using a slit coating device and annealed;

[0070] (4) The perovskite precursor solution is spread over the substrate in step (3) using slit coating, and then quickly transferred into a vacuum chamber. The vacuum is pumped to 10 Pa and maintained for 30 s. After that, the wet film after flash evaporation is annealed using the surface laser annealing process, and the total annealing time is 60 s to obtain a perovskite film;

[0071] (5) Using the technique of vacuum evaporation, 30 nm of C60 is evaporated on the basis of step 4);

[0072] (6) Using an atomic layer deposition device, 20 nm of SnO2 is deposited on the basis of step 5);

[0073] (7) Adopt the laser scribing technology to laser scribe P2 on the basis of step (6).

[0074] (8) Adopt the magnetron sputtering technology to deposit a 100-nm metal Cu electrode on the basis of step (7).

[0075] (9) Adopt the laser scribing technology to laser scribe P3 on the basis of step (8), and trim the edges of P4, and then attach the bus bar. Thus, the perovskite photovoltaic module is fabricated.

[0076] Example 2:

[0077] In this example, a large-area perovskite wet film is prepared by spin-coating under vacuum, and a stable FAPbI3 perovskite film is prepared by using the surface laser annealing process. The specific steps for film preparation are as follows:

[0078] (1) Place a 2.5 cm × 2.5 cm ITO glass into a cleaning rack, and clean the surface successively with glass cleaning agent, ultrapure water and anhydrous ethanol, and then dry it with nitrogen for standby.

[0079] (2) Weigh 0.6915 g of lead iodide and 0.2579 g of formamidinium iodide according to a molar ratio of 1:1, and 2-imidazolidinone with a molar ratio of 60%, dissolve them in 1 mL of DMF, and oscillate for 20 min until it becomes a complete solution to prepare a perovskite precursor solution with a concentration of 1.5 M.

[0080] (3) Take 20 μL of the perovskite precursor solution in step (2) and drop it between the substrate cooled to room temperature in step (1) and the doctor blade. The doctor blade evenly spreads the solution onto the substrate at a speed of 5 mm / s, and then quickly transfers it into a vacuum chamber, evacuate to 10 Pa and maintain for 10 s. After that, perform an annealing treatment on the flash-evaporated wet film by using the surface laser annealing process. The total annealing treatment time is 60 s to obtain the perovskite film.

[0081] Example 3:

[0082] In this example, a large-area perovskite wet film is prepared by slot-die coating under vacuum, and an efficient solar photovoltaic module is prepared by using the surface laser annealing process. The specific steps for film preparation are as follows:

[0083] (1) For a full-size silicon wafer with a size of 210 cm × 105 cm, prepare a composite layer on the N side of the crystalline silicon by using a magnetron sputtering device.

[0084] (2) Use a slot-die coating device to coat a SAM layer on the substrate in step (1) and perform an annealing treatment.

[0085] (3) The perovskite precursor solution is spread over the substrate in step 2) by slit coating, and then quickly transferred into a vacuum chamber, and evacuated to 10 Pa for 30 seconds. After completion, the wet film after flash evaporation is annealed by surface laser annealing for a total of 60 seconds to obtain a perovskite film.

[0086] Comparative Example 1:

[0087] In this embodiment, a large-area perovskite wet film is prepared by a slit coating vacuum method, and a high-efficiency solar photovoltaic module is prepared by a surface laser annealing process. The module preparation specifically includes the following steps:

[0088] (1) Use laser to scribe P1 on a 30 cm × 30 cm ITO glass and then put it into a cleaning machine for cleaning;

[0089] (2) Using magnetron sputtering equipment, a hole transport layer NiOx was prepared on an ITO sheet of 30 cm × 30 cm in size;

[0090] (3) coating a SAM layer on a NiOx substrate using a slit coating device and performing an annealing treatment;

[0091] (4) The perovskite precursor solution is spread over the substrate in step 3) by slit coating, and then quickly transferred into a vacuum chamber, evacuated to 10 Pa and maintained for 30 seconds, and then annealed for 60 seconds by hot stage annealing on the wet film after flash evaporation to obtain a perovskite film;

[0092] (5) using vacuum evaporation technology, evaporating 30 nm of C60 on the basis of step 4);

[0093] (6) Using an atomic layer deposition device, deposit 20 nm of SnO2 based on step 5);

[0094] (7) Using laser scribing technology, laser scribing P2 based on step 6);

[0095] (8) Using magnetron sputtering technology, evaporate a 100 nm thick metal Cu electrode based on step 7);

[0096] (9) Using laser scribing technology, laser scribing P3 and P4 are performed on the basis of step 8), and bus bars are attached. At this point, the perovskite photovoltaic module is completed.

[0097] Comparative Example 2:

[0098] In this embodiment, a large-area perovskite wet film is prepared by a slit coating vacuum method, and a high-efficiency solar photovoltaic module is prepared by a surface laser annealing process. The module preparation specifically includes the following steps:

[0099] (1) After laser scribing P1 on ITO glass with a size of 30 cm × 30 cm, it is put into a cleaning machine and cleaned thoroughly;

[0100] (2) Use a magnetron sputtering device to prepare a hole transport layer of NiOx on the 30 cm × 30 cm ITO;

[0101] (3) Use a slot coating device to coat the SAM layer on the NiOx substrate and perform annealing treatment;

[0102] (4) Use a slot coater to spread the perovskite precursor solution over the substrate in step 3), then quickly transfer it to a vacuum chamber, evacuate to 10 Pa and hold for 30 s. After that, perform a 30 - minute annealing treatment on the wet film after flash evaporation using a hot plate annealer to obtain a perovskite thin film;

[0103] (5) Using the technique of vacuum evaporation, deposit 30 nm of C60 on the basis of step 4);

[0104] (6) Using an atomic layer deposition device, deposit 20 nm of SnO2 on the basis of step 5);

[0105] (7) Using the laser scribing technique, laser scribe P2 on the basis of step 6);

[0106] (8) Using the technique of magnetron sputtering, deposit a 100 - nm metal Cu electrode on the basis of step 7);

[0107] (9) Using the laser scribing technique, laser scribe P3 and perform edge cleaning of P4 on the basis of step 8), and attach a bus bar. Thus, the perovskite photovoltaic module is prepared.

[0108] Comparative Example 3:

[0109] In this example, a large - area perovskite wet film is prepared by the spin - coating vacuum method, and a stable FAPbI3 perovskite thin film is prepared using the process of line - scanned laser annealing. The specific steps of thin - film preparation are as follows:

[0110] Step 1: Put ITO glass with a size of 2.5 cm × 2.5 cm into a cleaning rack, and successively clean the surface with glass cleaner, ultrapure water and absolute ethanol, and dry it with nitrogen for later use;

[0111] Step 2: Weigh 0.6915 g of lead iodide and 0.2579 g of formamidinium iodide in a molar ratio of 1:1 and 2 - imidazolidinone with a molar ratio of 60%, dissolve them in 1 mL of DMF, and oscillate for 20 min until it becomes a complete solution to prepare a perovskite precursor solution with a concentration of 1.5 M;

[0112] Step 3: Take 20 μL of the perovskite precursor solution in step 2) and drop it between the substrate cooled to room temperature in step 1) and the blade. The blade evenly scrapes the solution onto the substrate at a speed of 5 mm / s, and then quickly transfers it into the vacuum chamber. Vacuum is pumped to 10 Pa and maintained for 10 s. After that, line-scanning laser annealing is used to anneal the wet film after flash evaporation. The annealing time is 60 s to obtain the perovskite film.

[0113] Comparative Example 4:

[0114] In this example, a large-area perovskite wet film is prepared by the slit coating vacuum method, and a high-efficiency solar photovoltaic module is prepared using the surface laser annealing process. The film preparation specifically includes the following steps:

[0115] (1) Prepare a composite layer on the N side of the crystalline silicon of a full-size silicon wafer with a size of 210 cm × 105 cm using a magnetron sputtering device;

[0116] (2) Coat the SAM layer on the substrate in step 1) using a slit coating device and perform annealing treatment;

[0117] (3) Use slit coating to cover the substrate in step 2) with the perovskite precursor solution, and then quickly transfer it into the vacuum chamber. Vacuum is pumped to 10 Pa and maintained for 30 s. After that, hot plate annealing is used to anneal the wet film after flash evaporation for 30 min to obtain the perovskite film.

[0118] Performance testing of perovskite films and devices:

[0119] Use a scanning electron microscope (SEM) to observe the surface morphology of the perovskite film, use an X-ray diffractometer (XRD) to test the crystal structure of the perovskite, and use a J-V test instrument to characterize the optoelectronic properties of the prepared perovskite solar module.

[0120] Figure 2 It is a comparison chart of the surface morphologies of the perovskite films prepared in Example 1, Comparative Example 1, and Comparative Example 2. It can be seen from the figure that for Example 1 using surface laser annealing, compared with Comparative Example 1 with hot plate annealing for 60 s and Comparative Example 2 with hot plate annealing for 30 min, the perovskite film in Example 1 has larger and denser grain sizes, and there is no presence of other substances on the surface, while there are more shiny other substances in Comparative Example 1 and Comparative Example 2.

[0121] Figure 3 It is a comparison chart of the crystal structures of the perovskite films prepared in Example 1, Comparative Example 1, and Comparative Example 2. It can be seen from the figure that the intensity of the diffraction peaks of the perovskite film in Example 1 using surface laser annealing is higher, indicating better crystallization orientation, and there is no precipitation of PbI2, while there are diffraction peaks of PbI2 in the perovskite films of Comparative Example 1 with hot plate annealing for 60 s and Comparative Example 2 with hot plate annealing for 30 min.

[0122] Figure 4 are the J-V curve diagrams of the perovskite solar cells prepared in Example 1, Comparative Example 1 and Comparative Example 2 and the comparison diagrams of various photovoltaic parameters. It can be seen from the figures that in Example 1 using surface laser annealing: when the module area is 655.2 cm 2 , its open-circuit voltage (Voc) is 44.74 V, short-circuit current (Jsc) is 0.56 mA / cm 2 , fill factor (FF) is 77.95%, and finally the device energy conversion efficiency (PCE) is 19.46%. Comparative Example 1 with hot plate annealing for 60 s: its open-circuit voltage (Voc) is 43.24 V, short-circuit current (Jsc) is 0.44 mA / cm 2 , fill factor (FF) is 35.53%, and finally the device energy conversion efficiency (PCE) is 6.77%. Comparative Example 2 with hot plate annealing for 30 min: its open-circuit voltage (Voc) is 43.12 V, short-circuit current (Jsc) is 0.56 mA / cm 2 , fill factor (FF) is 78.00%, and finally the device energy conversion efficiency (PCE) is 18.73%.

[0123] Figure 5 are the comparison diagrams of the surface morphologies of the perovskite thin films prepared in Example 2 and Comparative Example 3. It can be seen from the figures that in Example 2 using surface laser annealing, compared with Comparative Example 3 with line-scanning laser annealing for 60 s, the grain size of the perovskite thin film is larger and denser, while there are more holes in the thin film prepared by line laser annealing.

[0124] Figure 6 are the comparison diagrams of the crystal structures of the perovskite thin films prepared in Example 2 and Comparative Example 3. It can be seen from the figures that the intensity of the diffraction peaks of the perovskite thin film in Example 2 using surface laser annealing is higher, indicating better crystallization orientation and no precipitation of PbI2, while there are diffraction peaks of PbI2 in the perovskite thin film of Comparative Example 3 with scanning laser annealing for 60 s.

[0125] Figure 7 are the comparison diagrams of the surface morphologies of the perovskite thin films prepared in Example 3 and Comparative Example 4. It can be seen from the figures that in Example 3 using surface laser annealing, compared with Comparative Example 4 with hot plate annealing for 30 min, the perovskite thin film is more dense, while there are flaky substances in the thin film prepared by hot plate annealing.

[0126] Figure 8It is a comparison diagram of the crystal structures of the perovskite thin films prepared in Example 3 and Comparative Example 4. It can be seen from the figure that the intensity of the diffraction peaks of the perovskite thin film in Example 3 using surface laser annealing is higher, indicating a better crystallization orientation, and there is no precipitation of PbI2, while there is a diffraction peak of PbI2 in the perovskite thin film of Comparative Example 4 annealed on a hot stage for 30 minutes.

[0127] In summary, the process of preparing perovskite thin films by surface laser annealing in the present invention mainly monitors the surface temperature of the perovskite thin film in real time by regulating the infrared temperature measurement system, and closed-loop controls the output power of the laser to avoid damage to the perovskite thin film caused by too high temperature. Compared with traditional hot stage annealing and line scanning laser annealing, surface laser annealing is more uniform, and local instantaneous heating can be achieved within milliseconds to seconds by high-energy density surface laser. This rapid temperature rise can quickly evaporate the solvent, promote the synchronous crystallization of the perovskite precursor, reduce the separate precipitation time window of PbI2, and prepare a perovskite layer thin film without pores and of high quality, thereby improving the performance of the device and enabling the preparation of highly efficient perovskite solar cell modules with an efficiency of 655.2 cm 2 2.

[0128] The above are only some embodiments of the present invention. For those of ordinary skill in the art, without departing from the creative concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention.

Claims

1. A method for regulating the crystallization of perovskite thin films based on surface laser annealing, characterized in that It includes the following steps: Prepare a perovskite wet film on a substrate; Adopt a vacuum flash evaporation process to assist the formation of the perovskite wet film; Construct an infrared temperature measurement system in an annealing device to be able to monitor the surface temperature distribution of the film in real time; In the annealing device, perform the following annealing process through a surface laser to obtain a perovskite film: In the preheating stage, a surface laser outputs low-power infrared-band laser to preheat the thin film, with a power density of 0.1 to 10 W / cm 2 , and the irradiation time is 0.1 to 60 s; During the main annealing stage, a surface laser outputs high-power infrared-band laser to irradiate the thin film, with a power density of 10-100 W / cm 2 , and the irradiation time is 0.1-60 s; And optionally, it may further include In the post-treatment stage, a surface laser outputs low-power infrared-band laser to perform secondary annealing on the thin film, with a power density of 0.1-10 W / cm 2 , and the irradiation time is 0.1-60 s.

2. The method for regulating the crystallization of perovskite thin films based on surface laser annealing according to claim 1, wherein During the preheating stage: control the substrate temperature to 80-120°C.

3. A method for regulating the crystallization of perovskite thin films based on surface laser annealing according to claim 1, characterized in that, During the main annealing stage: if the infrared temperature measurement system detects that the local temperature of a certain part of the film exceeds the critical value, immediately reduce the laser power to inhibit the precipitation of PbI2.

4. A method for regulating the crystallization of perovskite thin films based on surface laser annealing according to claim 1, characterized in that, Dynamically feedback the surface temperature of the film through the infrared temperature measurement system, and adjust the laser power in combination with the PID algorithm to control the temperature fluctuation range within ±2°C.

5. A method for regulating perovskite thin film crystallization based on surface laser annealing according to claim 4, characterized in that, The infrared temperature measurement system uses a high-precision infrared thermal imager.

6. A method for regulating the crystallization of perovskite thin films based on surface laser annealing according to claim 1, wherein, The spot size of the laser output by the surface laser is not less than the size of the substrate.

7. A method for regulating the crystallization of perovskite thin films based on surface laser annealing according to claim 6, characterized in that, The spot size range of the laser output by the surface laser is 1×1 cm 2 ~240×240 cm 2 .

8. A method for preparing a perovskite photovoltaic module, characterized in that, It includes the following steps: Provide an ITO glass substrate, use laser scribing P1 on the substrate and then clean it; Prepare a hole transport layer on the substrate; Coat a SAM layer on the hole transport layer and perform annealing treatment; Coat a perovskite precursor solution on the SAM layer, and quickly transfer it to a vacuum chamber, evacuate to 10 Pa and keep it for 30 s to obtain a perovskite wet film, and adopt a vacuum flash evaporation process to assist the formation of the perovskite wet film; Anneal the wet film after flash evaporation according to the method described in any one of claims 1 to 7 to obtain a perovskite film; The subsequent processes include evaporating and depositing layer C 60 layer, preparing the SnO2 layer, scribing P2, preparing the metal electrodes, scribing P3, and edge cleaning. Finally, a bus bar is attached to complete the preparation of the perovskite photovoltaic module.

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