Preparation method of perovskite solar thin film and passivation device

Abstract

The invention relates to a perovskite solar thin film preparation method and a passivation device, and the passivation method comprises the steps: carrying out the passivation of a perovskite wet film through passivation gas under a vacuum condition, and obtaining a perovskite thin film after annealing. According to the invention, through specific selection of the gas components in the passivation gas, the requirement for vacuum condition control precision is reduced, the perovskite wet film can be fully passivated, and the open-circuit voltage and the fill factor of the perovskite solar cell are improved, so that the photoelectric conversion efficiency of the perovskite solar cell is improved.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, and relates to a perovskite solar cell, and more particularly to a method for preparing a perovskite solar thin film and a passivation device. Background Technology

[0002] Perovskite is a compound material with an ABX3 three-dimensional structure, possessing excellent properties such as high light absorption coefficient, long carrier diffusion length, and tunable band gap, making it suitable as a light-absorbing layer in solar cells. Currently, the photoelectric conversion efficiency of perovskite solar cells is approaching the highest efficiency of crystalline silicon solar cells.

[0003] Large-area perovskite solar cells have low efficiency and require suitable fabrication methods. For example, the inherent edge effects of spin coating can lead to areas exceeding 10 cm². 2 Large-area perovskite solar cell films often exhibit uneven thickness. Currently, methods for preparing large-area perovskite solar cell films include spray coating, inkjet printing, physical vapor deposition, vapor-assisted solution coating, blade coating, and slot coating. Taking slot coating as an example, in preparing inverted perovskite solar cells, a gas flow is required to rapidly remove the solvent components from the perovskite solar cell film. The precision of controlling the gas flow rate, gas flow intensity, and time directly affects the number of defects in the perovskite solar cell film, and inaccurate control of the gas flow conditions directly impacts the photoelectric conversion efficiency of the solar cell.

[0004] Low-pressure crystallization is more suitable for preparing high-quality perovskite solar thin films. The principle is to allow the solvent in the perovskite solar thin film to evaporate at low or room temperature under vacuum conditions, promoting the crystallization of the perovskite material. Then, clean, dry air is used to restore the pressure in the cavity to standard atmospheric pressure. However, this method not only has high requirements for vacuum equipment, but also easily leads to defects in the perovskite solar thin film, affecting the efficiency of perovskite solar cells.

[0005] Therefore, there is a need to provide a method for preparing large-area perovskite solar thin films and a passivation device to improve the open-circuit voltage and fill factor of perovskite solar cells, thereby improving their photoelectric conversion efficiency. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing perovskite solar cell thin films and a passivation apparatus. The provided preparation method can fully passivate the perovskite wet film, thereby improving the open-circuit voltage and fill factor of the perovskite solar cell and thus improving the photoelectric conversion efficiency of the perovskite solar cell.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a perovskite solar cell thin film, the method comprising the following steps:

[0009] Under vacuum conditions, a passivating gas is used to passivate the perovskite wet film, and after annealing, a perovskite thin film is obtained.

[0010] The passivation gas includes any one or a combination of at least two of the following: N-octylpyridine tetrafluoroboronic acid, 1-dodecyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1,3-diethylimidazolium bis(trifluoromethanesulfonyl)imide, 1,3-dimethylimidazolium dinitrileamine, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, or 4-(trifluoromethyl)benzylamine.

[0011] The passivation gas described in this invention is liquid under standard conditions (25°C, 101.3 kPa). Under vacuum and heating conditions, it transforms from liquid to gas, achieving passivation treatment of the perovskite wet film. This invention, through specific selection of the gas composition in the passivation gas and utilizing the characteristic of uniform gas distribution, achieves uniform passivation of the perovskite solar cell thin film, significantly reducing surface defects and non-radiative recombination of electrons and holes, thereby improving the photoelectric conversion efficiency of perovskite solar cells.

[0012] Preferably, the initial concentration of the passivation gas during the passivation treatment is 0.25 mg / cm³. 3 Up to 2.5 mg / cm 3 .

[0013] Preferably, the preparation method includes the following steps:

[0014] S1: Set up passivation cavities and pre-extraction cavities that can be interconnected or isolated from each other.

[0015] S2: Isolate the passivation cavity and the pre-evacuation cavity, and pre-evacuate the pre-evacuation cavity.

[0016] S3: Place the substrate containing the perovskite wet film into the passivation cavity, and introduce passivation gas into the passivation cavity.

[0017] S4: After passivation is completed, connect the pre-extraction chamber and the passivation chamber, and simultaneously apply negative pressure to the pre-extraction chamber or the passivation chamber until crystallization occurs, and discharge the volatile solvent gas.

[0018] S5: After crystallization is completed, annealing is performed.

[0019] Preferably, in step S3, the passivation cavity is simultaneously subjected to vacuum treatment and passivation gas is introduced.

[0020] Preferably, a passivation chamber and a passivation steam chamber that can be interconnected or isolated are provided.

[0021] The passivation chamber and the passivation vapor chamber are isolated, and the passivation vapor chamber is pre-evacuated.

[0022] Passivating gas is introduced into the passivating vapor chamber or a passivation source is heated in the passivating vapor chamber to form passivating gas.

[0023] When the passivation gas in the passivation vapor chamber reaches a predetermined concentration range, the passivation chamber and the passivation vapor chamber are connected.

[0024] Preferably, the absolute pressure during the passivation treatment is 2 kPa to 10 kPa.

[0025] Preferably, the passivation treatment time is 5s to 15s.

[0026] Preferably, after the passivation treatment is completed, the sample is left to stand under vacuum for more than 20 seconds.

[0027] Preferably, the passivation treatment is performed before annealing; or, the passivation treatment is performed during the annealing process.

[0028] In a second aspect, the present invention provides a passivation apparatus for a perovskite thin film prepared by the preparation method described in the first aspect, the passivation apparatus comprising a passivation section and a passivation gas generating section.

[0029] The passivation section includes a passivation cavity and a pre-vacuum cavity formed by a first partition; the pre-vacuum cavity is connected to a first vacuum device; the passivation cavity is used to place the perovskite wet film to be passivated.

[0030] The passivation gas generator is connected to the second vacuum pumping device and has a heating device inside; the passivation gas generator is used to provide passivation gas to the passivation unit.

[0031] Preferably, the passivation device includes a passivation gas generating section, a passivation chamber, and a pre-extraction chamber running from bottom to top.

[0032] A first partition is movably disposed between the passivation cavity and the pre-extraction cavity, and the first partition separates or connects the passivation cavity and the pre-extraction cavity.

[0033] The passivation gas generating unit includes a passivation vapor chamber, and a second partition is movably disposed between the passivation vapor chamber and the passivation chamber. The second partition separates or connects the passivation chamber and the passivation vapor chamber.

[0034] The passivation cavity is provided with an opening and closing door for picking up and putting in the substrate.

[0035] Preferably, the passivation cavity is provided with a heating plate for supporting and heating the substrate.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The passivation gas described in this invention is liquid under standard conditions (25°C, 101.3 kPa). Under vacuum and heating conditions, it transforms from liquid to gas, achieving passivation treatment of the perovskite wet film. This invention, through specific selection of the gas composition in the passivation gas and utilizing the characteristic of uniform gas distribution, achieves uniform passivation of the perovskite solar cell thin film, significantly reducing surface defects and non-radiative recombination of electrons and holes, thereby improving the photoelectric conversion efficiency of perovskite solar cells. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the passivation device provided in Example 1.

[0039] Figure 2 The image shows the surface SEM image of the perovskite solar cell thin film obtained in Example 1.

[0040] Figure 3 The image shows the surface SEM image of the perovskite solar cell thin film obtained in Example 6.

[0041] Figure 4 The image shows the surface SEM image of the perovskite solar cell thin film obtained in Example 7.

[0042] Figure 5 The surface SEM image of the perovskite solar cell thin film obtained in Example 8 is shown.

[0043] Figure 6 The surface SEM image of the perovskite solar cell thin film obtained in Example 9 is shown.

[0044] Figure 7 The image shows the surface SEM image of the perovskite solar thin film obtained in Application Example 10.

[0045] Figure 8 The image shows the surface SEM image of the perovskite solar cell thin film obtained in Application Example 11.

[0046] Wherein: 1, pre-extraction chamber; 2, first partition; 3, passivation chamber; 4, stage; 5, first vacuum gauge; 6, first vacuum valve; 7, first vacuum pump; 8, stage track; 9, second vacuum gauge; 10, second vacuum valve; 11, second vacuum pump; 12, second partition; 13, passivation vapor chamber; 14, liquid holding stage; 15, heating stage; 16, connecting valve. Detailed Implementation

[0047] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0048] An embodiment of the present invention provides a method for preparing a perovskite solar cell thin film, the method comprising the following steps:

[0049] Under vacuum conditions, a passivating gas is used to passivate the perovskite wet film, and after annealing, a perovskite thin film is obtained.

[0050] The passivation gas includes any one or a combination of at least two of the following: N-octylpyridine tetrafluoroboronic acid, 1-dodecyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1,3-diethylimidazolium bis(trifluoromethanesulfonyl)imide, 1,3-dimethylimidazolium dinitrileamine, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, or 4-(trifluoromethyl)benzylamine.

[0051] The passivation gas described in this invention is liquid under standard conditions (25°C, 101.3 kPa). Under vacuum and heating conditions, it transforms from liquid to gas, achieving passivation treatment of the perovskite wet film. This invention, through specific selection of the gas composition in the passivation gas and utilizing the characteristic of uniform gas distribution, achieves uniform passivation of the perovskite solar cell thin film, significantly reducing surface defects and non-radiative recombination of electrons and holes, thereby improving the photoelectric conversion efficiency of perovskite solar cells.

[0052] The perovskite wet film described in this invention refers to a thin film state in which the perovskite precursor solution is applied to a conventional substrate but is not completely dry and still contains a large amount of solvent.

[0053] In some embodiments, the concentration of the passivation gas during the passivation treatment is 0.25 mg / cm³. 3 Up to 2.5 mg / cm 3 For example, it could be 0.25 mg / cm³. 3 0.5 mg / cm 3 1mg / cm 3 1.5 mg / cm 3 2mg / cm 3 Or 2.5 mg / cm 3 However, this does not limit the listed values; any other unlisted values ​​within the range are also applicable.

[0054] In some embodiments, the preparation method includes the following steps:

[0055] S1: Set up passivation cavities and pre-extraction cavities that can be interconnected or isolated from each other.

[0056] S2: Isolate the passivation cavity and the pre-evacuation cavity, and pre-evacuate the pre-evacuation cavity.

[0057] S3: Place the substrate containing the perovskite wet film into the passivation cavity, and introduce passivation gas into the passivation cavity.

[0058] S4: After passivation is completed, connect the pre-extraction chamber and the passivation chamber, and simultaneously apply negative pressure to the pre-extraction chamber or the passivation chamber until crystallization occurs, and discharge the volatile solvent gas.

[0059] S5: After crystallization is completed, annealing is performed.

[0060] In some embodiments, the final absolute pressure of the pre-vacuuming in step S2 is 1 × 10⁻⁶. -2 Pa to 50 Pa, for example, it could be 1×10 -2 Pa, 1×10 -1 Pa, 1 Pa, 5 Pa, 10 Pa, 20 Pa, 30 Pa, 40 Pa or 50 Pa, but not limited to the listed values, and other unlisted values ​​within the range also apply.

[0061] If the time required to transition from atmospheric pressure to the required negative pressure is too long during the crystallization process of perovskite wet films, the quality of perovskite crystallization will deteriorate. In this invention, by setting up a passivation chamber and a pre-vacuum chamber, the pre-vacuum chamber is pre-evacuated before passivation treatment. When the passivation chamber and the pre-vacuum chamber are connected, the passivation chamber can quickly reach a negative pressure state, which is beneficial for solvent precipitation in the perovskite wet film, reduces the time consumption from atmospheric pressure to negative pressure, lowers the requirements for vacuum equipment, and extends the crystallization window period.

[0062] In some embodiments, the absolute pressure of the crystallization state in step S4 is below 50 Pa, for example, it can be 1 Pa, 5 Pa, 10 Pa, 20 Pa, 30 Pa, 40 Pa or 50 Pa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0063] In some embodiments, the duration of the crystallization state in step S4 is 20s or more, for example, it can be 20s, 25s, 30s, 35s, 40s, 45s or 50s, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 20s to 40s.

[0064] In some embodiments, in step S3, the passivation cavity is simultaneously subjected to vacuum treatment and passivation gas is introduced.

[0065] Passivation under negative pressure can directly skip the time consumption of transitioning from atmospheric pressure to negative pressure, ensuring that the passivation process begins in the early stages of crystallization and guaranteeing the crystallization quality of perovskite.

[0066] In some embodiments, simultaneously performing vacuum treatment and introducing passivating gas into the passivation cavity includes:

[0067] The system includes passivation chambers and passivation vapor chambers that can be interconnected or isolated from each other.

[0068] The passivation chamber and the passivation vapor chamber are isolated, and the passivation vapor chamber is pre-evacuated.

[0069] Passivating gas is introduced into the passivating vapor chamber or a passivation source is heated in the passivating vapor chamber to form passivating gas.

[0070] When the passivation gas in the passivation vapor chamber reaches a predetermined concentration range, the passivation chamber and the passivation vapor chamber are connected.

[0071] In some embodiments, the final absolute pressure of the pre-vacuuming of the passivation vapor chamber is 1 kPa to 5 kPa, for example, it can be 1 kPa, 2 kPa, 3 kPa, 4 kPa or 5 kPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0072] In some embodiments, the predetermined concentration range refers to a passivation gas concentration of 0.25 mg / cm³ during passivation treatment when the passivation chamber and the passivation vapor chamber are connected. 3 Up to 2.5 mg / cm 3 .

[0073] In some embodiments, the absolute pressure during the passivation process is 2 kPa to 10 kPa, for example, it can be 2 kPa, 4 kPa, 6 kPa, 8 kPa or 10 kPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0074] In some embodiments, the temperature during the passivation process is such that the passivation gas remains in a gaseous state and is below the annealing temperature. For example, it may be 50°C, 60°C, 70°C, 80°C, 90°C, or 100°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0075] A suitable passivation time can ensure the passivation effect on the perovskite wet film, as well as the charge transport of the battery and prevent a decrease in current density.

[0076] In some embodiments, the passivation process takes 5 to 15 seconds, for example, 5 seconds, 8 seconds, 10 seconds, 12 seconds or 15 seconds, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0077] As one of the preferred technical solutions of the present invention, the passivation treatment is performed before the annealing treatment.

[0078] In some embodiments, the annealing temperature is between 120°C and 155°C, for example, 120°C, 130°C, 140°C, 145°C, 148°C, 150°C, 152°C or 155°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0079] In some embodiments, the annealing time is from 10 min to 60 min, for example, it can be 10 min, 12 min, 15 min, 18 min, 20 min, 30 min, 40 min, 50 min or 60 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0080] As a second preferred technical solution of the present invention, the passivation treatment is performed during the annealing process.

[0081] In some embodiments, the annealing temperature is between 120°C and 155°C, for example, 120°C, 130°C, 140°C, 145°C, 148°C, 150°C, 152°C or 155°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0082] In some embodiments, the annealing time is from 10 min to 60 min, for example, it can be 10 min, 12 min, 15 min, 18 min, 20 min, 30 min, 40 min, 50 min or 60 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0083] An embodiment of the present invention provides a passivation device for perovskite thin films, the passivation device comprising a passivation section and a passivation gas generation section.

[0084] The passivation section includes a passivation cavity and a pre-vacuum cavity formed by a first partition; the pre-vacuum cavity is connected to a first vacuum device; the passivation cavity is used to place the perovskite wet film to be passivated.

[0085] The passivation gas generator is connected to the second vacuum pumping device and has a heating device inside; the passivation gas generator is used to provide passivation gas to the passivation unit.

[0086] In some embodiments, the interior of the passivation device includes a passivation gas generating section, a passivation chamber, and a pre-extraction chamber, running from bottom to top.

[0087] A first partition is movably disposed between the passivation cavity and the pre-extraction cavity, and the first partition separates or connects the passivation cavity and the pre-extraction cavity.

[0088] The passivation gas generating unit includes a passivation vapor chamber, and a second partition is movably disposed between the passivation vapor chamber and the passivation chamber. The second partition separates or connects the passivation chamber and the passivation vapor chamber.

[0089] The passivation cavity is provided with an opening and closing door for picking up and putting in the substrate.

[0090] In some embodiments, a heating plate for supporting and heating the substrate is provided within the passivation cavity.

[0091] In this invention, the provision of a heating plate within the passivation cavity for supporting and heating the substrate refers to the provision of a stage within the passivation cavity for supporting the substrate, and a heating plate track for facilitating the movement of the stage. The stage is either a power-on / off heating plate or a heating plate mounted on a stage for selectively heating the substrate.

[0092] The method for passivating a perovskite wet film using the passivation device includes:

[0093] (1) Use the second vacuum device to adjust the absolute pressure in the passivation steam chamber, and then use the heating device to convert the liquid material placed in the passivation steam chamber into a gaseous state.

[0094] (2) Use the first vacuum device to adjust the absolute pressure in the pre-vacuum chamber; open the opening and closing door and place the substrate in the passivation chamber.

[0095] (3) Passivating gas is introduced into the passivation vapor chamber or a passivation source is heated in the passivation vapor chamber to form passivating gas; when the passivating gas in the passivation vapor chamber reaches a predetermined concentration range, the second partition is opened to connect the passivation chamber and the passivation vapor chamber, and the gas from the passivation gas generator is used to passivate the perovskite wet film; the second partition is closed to isolate the passivation gas generator from the passivation chamber.

[0096] (4) Open the first partition to connect the pre-extraction chamber and the passivation chamber, use the first vacuum device to extract the gas in the passivation chamber to the crystallization state, discharge the volatile solvent gas, and close the first vacuum device; then open the opening and closing chamber door to restore the pressure in the passivation chamber to normal pressure.

[0097] (5) The passivated perovskite film is annealed.

[0098] In some embodiments, the passivation steam chamber, passivation chamber, and pre-extraction chamber have the same volume.

[0099] In some embodiments, the passivation gas generator is connected to the passivation chamber via a gas delivery pipeline.

[0100] In this invention, when the passivation gas generator is connected to the passivation cavity via a gas delivery pipeline, necessary valves are also provided on the gas delivery pipeline.

[0101] Example 1

[0102] This embodiment provides a method such as Figure 1 The passivation device shown includes a passivation gas generating section, a passivation chamber 3, and a pre-extraction chamber 1, arranged from bottom to top. A first partition 2 is movably disposed between the passivation chamber 3 and the pre-extraction chamber 1, separating or connecting the passivation chamber 3 and the pre-extraction chamber 1. The passivation gas generating section includes a passivation vapor chamber 13, and a second partition 12 is movably disposed between the passivation vapor chamber 13 and the passivation chamber 3, separating or connecting the passivation chamber 3 and the passivation vapor chamber 13. The side wall of the passivation chamber 3 is provided with an opening and closing door for picking up and putting in the substrate and a connecting valve 16.

[0103] The passivation steam chamber 13, passivation chamber 3 and pre-extraction chamber 1 each have a volume of 400mm×400mm×180mm.

[0104] The pre-extraction chamber 1 is connected to the first vacuum pump 7, and the connecting pipeline is equipped with a first vacuum gauge 5 and a first vacuum valve 6.

[0105] The passivation cavity 3 is provided with a stage 4 for supporting the substrate and a stage track 8 for facilitating the movement of the stage 4. The stage 4 is a heating plate that can be switched on and off, or the stage 4 is provided with a heating plate that can be switched on and off, for selectively heating the substrate.

[0106] The passivation vapor chamber 13 is connected to the second vacuum pump 11, and a second vacuum gauge 9 and a second vacuum valve 10 are installed on the connecting pipeline. The passivation gas generating unit is equipped with a heating platform 15 and a liquid holding platform 14 placed on the heating platform 15, and the liquid material that forms the passivation gas is placed in the liquid holding platform 14.

[0107] Example 2

[0108] This embodiment provides a passivation device, which includes a passivation section and a passivation gas generating section that are separately arranged.

[0109] The passivation section includes a passivation cavity and a pre-extraction cavity; a first partition is movably disposed between the passivation cavity and the pre-extraction cavity, the first partition separating or connecting the passivation cavity and the pre-extraction cavity; the side wall of the passivation cavity is provided with an opening and closing door for picking up and putting in the substrate and a connecting valve.

[0110] The passivation gas generating section includes a passivation vapor chamber; the volumes of the passivation vapor chamber, the passivation gas generating section, the passivation chamber, and the pre-extraction chamber are each 400mm×400mm×180mm.

[0111] The pre-extraction chamber is connected to the first vacuum pump, and a first vacuum gauge and a first vacuum valve are installed on the connecting pipeline. The passivation chamber contains a support plate for the substrate and a track for the support plate to facilitate its movement. The stage is either a power-on / off heating plate or a power-on / off heating plate is installed on the stage, for selectively heating the substrate.

[0112] The passivation vapor chamber is connected to a second vacuum pump, and a second vacuum gauge and a second vacuum valve are installed on the connecting pipeline. Inside the passivation vapor chamber is a heating platform and a liquid holding platform placed on the heating platform, where the liquid material forming the passivation gas is placed.

[0113] The passivation steam chamber is connected to the passivation chamber via a gas delivery pipeline.

[0114] Application Example 1

[0115] This application example provides a method for fabricating a perovskite solar cell, including:

[0116] (a) A 3 mm thick, 30 cm × 30 cm FTO (fluorine-doped tin oxide) conductive glass surface was cleaned, and a 15 nm thick nickel oxide layer was prepared by magnetron sputtering to obtain a substrate for setting the perovskite wet film. A 0.5 mL, 1.1 mol / L FA solution was then coated onto the surface of the nickel oxide layer. 0.9 Cs 0.1 A PbI3 perovskite precursor solution was used to obtain a substrate with a perovskite wet film.

[0117] The perovskite solar thin film was prepared using the passivation device provided in Example 1.

[0118] (b) Turn on the second vacuum pump and the second vacuum valve, adjust the absolute pressure in the passivation vapor chamber to 3 kPa, and close the second vacuum valve; heat the liquid in the liquid container through the heating platform to convert it into a gaseous state, forming a passivation gas with N-octylpyridine tetrafluoroboric acid as its component.

[0119] (c) Turn on the first vacuum pump and the first vacuum valve to evacuate the pre-evacuation chamber to make its absolute pressure reach 50Pa; then place the substrate with the perovskite wet film on the stage in the passivation chamber by opening and closing the chamber door.

[0120] (d) Open the second partition to connect the passivation chamber and the passivation vapor chamber, with the concentration of the passivation gas being 1.2 mg / cm³.3 Passivate the perovskite wet film with passivating gas for 10 seconds, then close the second partition to isolate the passivation vapor chamber from the passivation chamber.

[0121] (e) Open the first partition to connect the pre-extraction chamber and the passivation chamber, use the first vacuum pump to extract the gas in the passivation chamber to the crystallization state (absolute pressure reduced to 50 Pa), let it stand for 30 s, discharge the volatile solvent gas, and close the first vacuum pump and the first vacuum valve; then open the connecting valve to restore the pressure in the passivation chamber to normal pressure.

[0122] (f) Remove the passivated perovskite film and anneal it in an annealing furnace at 150°C for 15 minutes to obtain a film with a thickness of 500 nm and a material of FA. 0.9 Cs 0.1 PbI3 perovskite solar cell film. The surface SEM image of the obtained perovskite solar cell film is shown below. Figure 2 As shown.

[0123] Finally, 25 nm thick fullerene (C) films were sequentially deposited on the surface of the perovskite solar film. 60 A perovskite solar cell was obtained by combining a 5 nm thick 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) layer and an 80 nm thick copper electrode layer.

[0124] Application Example 2

[0125] This application example provides a method for fabricating a perovskite solar cell, which is the same as application example 1 except that the passivation time in step (d) is 5 s.

[0126] Application Example 3

[0127] This application example provides a method for fabricating a perovskite solar cell, which is the same as application example 1 except that the passivation time in step (d) is 15 s.

[0128] Application Example 4

[0129] This application example provides a method for fabricating a perovskite solar cell, except that the concentration of the passivation gas in step (d) is 0.25 mg / cm³. 3 Except for the above, everything else is the same as in Application Example 1.

[0130] Application Example 5

[0131] This application example provides a method for fabricating a perovskite solar cell, except that the concentration of the passivation gas in step (d) is 2.5 mg / cm³. 3 Except for the above, everything else is the same as in Application Example 1.

[0132] Application Example 6

[0133] This application example provides a method for preparing a perovskite solar cell, which is the same as Application Example 1 except that the composition of the passivation gas is replaced by 1-dodecyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide instead of N-octylpyridine tetrafluoroboronic acid.

[0134] The surface SEM image of the perovskite solar thin film obtained in this application example is as follows: Figure 3 As shown.

[0135] Application Example 7

[0136] This application example provides a method for fabricating a perovskite solar cell, which is the same as Application Example 1 except that the composition of the passivation gas is replaced by 1,3-diethylimidazolium bis(trifluoromethanesulfonyl)imide instead of N-octylpyridine tetrafluoroboronic acid.

[0137] The surface SEM image of the perovskite solar thin film obtained in this application example is as follows: Figure 4 As shown.

[0138] Application Example 8

[0139] This application example provides a method for fabricating a perovskite solar cell, which is the same as Application Example 1 except that the composition of the passivation gas is replaced by 1,3-dimethylimidazolium dinitrileamine instead of N-octylpyridine tetrafluoroboronic acid.

[0140] The surface SEM image of the perovskite solar thin film obtained in this application example is as follows: Figure 5 As shown.

[0141] Application Example 9

[0142] This application example provides a method for preparing a perovskite solar cell, which is the same as Application Example 1 except that the composition of the passivation gas is replaced by 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide instead of N-octylpyridine tetrafluoroboronic acid.

[0143] The surface SEM image of the perovskite solar thin film obtained in this application example is as follows: Figure 6 As shown.

[0144] Application Example 10

[0145] This application example provides a method for fabricating a perovskite solar cell, which is the same as Application Example 1 except that the composition of the passivation gas is replaced by 4-(trifluoromethyl)benzylamine instead of N-octylpyridine tetrafluoroboric acid.

[0146] The surface SEM image of the perovskite solar thin film obtained in this application example is as follows: Figure 7 As shown.

[0147] Application Example 11

[0148] This application example provides a method for fabricating a perovskite solar cell, including:

[0149] (a) A 3 mm thick, 30 cm × 30 cm FTO (fluorine-doped tin oxide) conductive glass surface was cleaned, and a 15 nm thick nickel oxide layer was prepared by magnetron sputtering to obtain a substrate for setting the perovskite wet film. A 0.5 mL, 1.1 mol / L FA solution was then coated onto the surface of the nickel oxide layer. 0.9 Cs 0.1 A PbI3 perovskite precursor solution was used to obtain a substrate containing a perovskite wet film.

[0150] The perovskite solar thin film was prepared using the passivation device provided in Example 1.

[0151] (b) Open the first vacuum pump and the first vacuum valve to evacuate the pre-evacuation chamber until its absolute pressure reaches 50 Pa.

[0152] (c) Open the door to the passivation chamber, place the substrate containing the perovskite wet film into the passivation chamber, seal the passivation chamber, and introduce passivation gas into the passivation chamber. Heat the substrate to 150°C using a heating plate and anneal for 15 minutes. The annealing is carried out in the passivation gas, which is N-octylpyridine tetrafluoroboric acid with a concentration of 1.2 mg / cm³. 3 ;

[0153] (d) During annealing, the first partition is opened to extract the gas from the pre-evacuation chamber and passivation chamber. After annealing, the first vacuum pump and the first vacuum valve are closed. A perovskite solar cell thin film with a thickness of 500 nm is obtained. The surface SEM image of the perovskite solar cell thin film obtained in this application example is shown below. Figure 8 As shown.

[0154] Finally, 25 nm thick fullerene (C) films were sequentially deposited on the surface of the perovskite solar film. 60 A perovskite solar cell was obtained by combining a 5 nm thick 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) layer and an 80 nm thick copper electrode layer.

[0155] Application Example 12

[0156] This application example provides a method for fabricating a perovskite solar cell, including:

[0157] (a) A 3 mm thick, 30 cm × 30 cm FTO (fluorine-doped tin oxide) conductive glass surface was cleaned, and a 15 nm thick nickel oxide layer was prepared by magnetron sputtering to obtain a substrate for setting the perovskite wet film. A 0.5 mL, 1.1 mol / L FA solution was then coated onto the surface of the nickel oxide layer. 0.9Cs 0.1 PbI3 perovskite precursor solution was used to obtain a perovskite wet film.

[0158] The perovskite solar cell thin film was prepared using the passivation apparatus provided in Example 2.

[0159] (b) Turn on the second vacuum pump and the second vacuum valve, adjust the absolute pressure in the passivation vapor chamber to 3 kPa, and close the second vacuum valve; heat the liquid in the liquid container through the heating platform to convert it into a gaseous state, forming a passivation gas composed of N-octylpyridine tetrafluoroboric acid.

[0160] (c) Turn on the first vacuum pump and the first vacuum valve to evacuate the pre-evacuation chamber to make its absolute pressure reach 50Pa; then place the substrate with the perovskite wet film on the heating plate in the passivation chamber by opening and closing the chamber door.

[0161] (d) Connect the passivation vapor chamber and the passivation chamber through a gas delivery pipeline, with the concentration of passivation gas in the passivation chamber being 1.2 mg / cm³. 3 The perovskite wet film was passivated with passivating gas for 10 seconds, and the gas delivery pipeline was disconnected to isolate the passivation vapor chamber from the passivation chamber.

[0162] (e) Open the first partition to connect the pre-extraction chamber and the passivation chamber, use the first vacuum pump to extract the gas in the passivation chamber to the crystallization state (absolute pressure reduced to 50 Pa), let it stand for 30 s, discharge the volatile solvent gas, and close the first vacuum pump and the first vacuum valve; then open the connecting valve to restore the pressure in the passivation chamber to normal pressure.

[0163] (f) Remove the passivated perovskite film and anneal it in an annealing furnace at 150°C for 15 minutes to obtain a film with a thickness of 500 nm and a material of FA. 0.9 Cs 0.1 PbI3 perovskite solar thin films.

[0164] Finally, 25 nm thick fullerene (C) films were sequentially deposited on the surface of the perovskite solar film. 60 A perovskite solar cell was obtained by combining a 5 nm thick 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) layer and an 80 nm thick copper electrode layer.

[0165] Comparative Application Example 1

[0166] This comparative application example provides a method for fabricating a perovskite solar cell, including:

[0167] (a) Providing a perovskite wet film: A 15 nm thick nickel oxide layer was prepared by magnetron sputtering on a cleaned 3 mm thick, 30 cm × 30 cm FTO (fluorine-doped tin oxide) conductive glass surface. 50 mL of 1.1 mol / L FA solution was then coated onto the surface of the nickel oxide layer. 0.9 Cs 0.1 PbI3 perovskite precursor solution was used to obtain a perovskite wet film.

[0168] The perovskite solar thin film was prepared using the passivation device provided in Example 1.

[0169] (b) Turn on the second vacuum pump and the second vacuum valve, adjust the absolute pressure in the passivation gas generator to 3 kPa, and close the second vacuum valve.

[0170] (c) Turn on the first vacuum pump and the first vacuum valve to evacuate the pre-evacuation chamber to make its absolute pressure reach 50Pa; then place the perovskite wet film on the stage in the passivation chamber.

[0171] (d) Open the second partition to connect the passivation gas generator with the passivation chamber for 10 seconds, then close the second partition.

[0172] (e) Open the first partition, and after the gas in the passivation chamber is extracted, the absolute pressure drops to 50 Pa. Let it stand for 30 seconds, and then close the first vacuum pump and the first vacuum valve.

[0173] (f) Open the connecting valve on the side wall of the passivation chamber to restore the absolute pressure of the passivation chamber to atmospheric pressure. Then, remove the passivated perovskite film and anneal it in an annealing furnace at 150°C for 15 minutes to obtain a film with a thickness of 500 nm and made of FA material. 0.9 Cs 0.1 PbI3 perovskite solar thin films.

[0174] Finally, 25 nm thick fullerene (C) films were sequentially deposited on the surface of the perovskite solar film. 60 A perovskite solar cell was obtained by combining a 5 nm thick 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) layer and an 80 nm thick copper electrode layer.

[0175] Comparative Application Example 2

[0176] This comparative application example provides a method for fabricating a perovskite solar cell, including:

[0177] (a) Providing a perovskite wet film: A 15 nm thick nickel oxide layer was prepared by magnetron sputtering on a cleaned 3 mm thick, 30 cm × 30 cm FTO (fluorine-doped tin oxide) conductive glass surface. 50 mL of 1.1 mol / L FA solution was then coated onto the surface of the nickel oxide layer.0.9 Cs 0.1 PbI3 perovskite precursor solution was used to obtain a perovskite wet film.

[0178] Fabrication of perovskite solar thin films using existing crystallization equipment:

[0179] The existing crystallization device only includes a crystallization cavity and a vacuum pump connected to the crystallization cavity, wherein the crystallization cavity is equivalent to the passivation cavity in Example 1.

[0180] (b) The substrate containing the perovskite wet film is placed in the passivation chamber, and a vacuum of 50 Pa is applied. N-octylpyridine tetrafluoroboric acid, a passivation gas, is then introduced into the chamber. The concentration of the passivation gas in the passivation chamber is 1.2 mg / cm³. 3 The passivation time is 10s;

[0181] (c) Restore the absolute pressure of the passivation chamber to atmospheric pressure, then remove the passivated perovskite film and anneal it in an annealing furnace at 150°C for 15 minutes; to obtain a film with a thickness of 500 nm and made of FA material. 0.9 Cs 0.1 PbI3 perovskite solar thin films.

[0182] Finally, a 25 nm thick fullerene (C60) layer, a 5 nm thick 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) layer, and an 80 nm thick copper electrode layer were sequentially deposited on the surface of the perovskite solar cell to obtain the perovskite solar cell.

[0183] Performance testing

[0184] The perovskite solar cells obtained from the above application examples and comparative application examples were tested, including current-voltage tests under standard sunlight with a light intensity of 100 mW / cm². 2 The testing instruments include conventional solar simulators and digital source meters, and the photovoltaic parameters tested include open-circuit voltage (V). oc ), short-circuit current (I) sc The results of the calculation of fill factor (FF) and photoelectric conversion efficiency (PCE) are shown in Table 1.

[0185] Table 1

[0186]

[0187]

[0188] From the above data, it can be seen that in Application Examples 1-3, if the passivation time is too short, the passivation is insufficient; if the passivation time is too long, excessive passivation gas will hinder charge transport to some extent. In Application Examples 4-5, if the passivation gas concentration is too low, the passivation is insufficient; if the passivation gas concentration is too high, excessive passivation gas will hinder charge transport to some extent, leading to performance degradation. In Application Examples 6-10, various passivation gases were used, all of which achieved good passivation effects and good battery performance. In Application Example 11, introducing passivation gas while annealing the perovskite thin film also significantly improved the battery efficiency. In Application Example 12, the method of gradually introducing passivation gas into the passivation chamber resulted in a slight decrease in efficiency compared to Application Examples 1-11, but still a certain improvement compared to Application Examples 1-2. The decrease in efficiency is due to the gradual introduction of passivation gas, which resulted in insufficient passivation capability in the early stages, but it still demonstrates the usability of the passivation gas. In Comparative Application Example 1, the passivation device of Example 1 was used, but no passivation gas was used. This still represents an improvement over the prior art method of crystallization in a vacuum chamber (which typically has an efficiency close to 17%). In Comparative Application Example 2, a prior art crystallization device was used, and passivation gas was introduced. The battery efficiency increased, but because the device of Example 1 was not used, the efficiency improvement was slightly less than in Application Examples 1-3.

[0189] In summary, the passivation gas described in this invention is liquid under standard conditions (25°C, 101.3 kPa). Under vacuum and heating conditions, it transforms from liquid to gas, thus achieving passivation treatment of the perovskite wet film. This invention, through specific selection of the gas composition in the passivation gas and utilizing the characteristic of uniform gas distribution, achieves uniform passivation of the perovskite solar cell thin film, significantly reducing surface defects and non-radiative recombination of electrons and holes, thereby improving the photoelectric conversion efficiency of perovskite solar cells.

[0190] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a perovskite solar cell thin film, characterized in that, The preparation method includes the following steps: Under vacuum conditions, a perovskite wet film is passivated using a passivating gas, and then annealed to obtain a perovskite thin film. The passivation gas includes any one or a combination of at least two of the following: N-octylpyridine tetrafluoroboronic acid, 1-dodecyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1,3-diethylimidazolium bis(trifluoromethanesulfonyl)imide, 1,3-dimethylimidazolium dinitrileamine, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, or 4-(trifluoromethyl)benzylamine.

2. The preparation method according to claim 1, characterized in that, The concentration of the passivation gas during the passivation treatment is 0.25 mg / cm³. 3 Up to 2.5 mg / cm 3 .

3. The preparation method according to claim 1, characterized in that, S1: Set up passivation cavities and pre-extraction cavities that can be interconnected or isolated from each other; S2: Separate the passivation cavity and the pre-evacuation cavity, and pre-evacuate the pre-evacuation cavity; S3: Place the substrate containing the perovskite wet film in the passivation cavity and introduce passivation gas into the passivation cavity; S4: After passivation is completed, connect the pre-extraction chamber and the passivation chamber, and simultaneously apply negative pressure to the pre-extraction chamber or the passivation chamber until crystallization occurs, and discharge the volatile solvent gas. S5: After crystallization is completed, annealing is performed.

4. The preparation method according to claim 3, characterized in that, In step S3, the passivation cavity is simultaneously subjected to vacuum treatment and passivation gas is introduced.

5. The preparation method according to claim 4, characterized in that, Set up passivation chambers and passivation vapor chambers that can be interconnected or isolated from each other; The passivation chamber and the passivation vapor chamber are isolated, and the passivation vapor chamber is pre-evacuated; Passivating gas is introduced into the passivating vapor chamber or a passivation source is heated in the passivating vapor chamber to form passivating gas; When the passivation gas in the passivation vapor chamber reaches a predetermined concentration range, the passivation chamber and the passivation vapor chamber are connected.

6. The preparation method according to claim 4 or 5, characterized in that, The absolute pressure during the passivation treatment is 2 kPa to 10 kPa. And / or, the passivation treatment time is 5s to 15s.

7. The preparation method according to claim 1 or 2, characterized in that, The passivation process is performed before annealing; Alternatively, the passivation process may be performed during the annealing process.

8. A passivation apparatus for a perovskite thin film prepared by any one of claims 1 to 7, characterized in that, The passivation device includes a passivation section and a passivation gas generating section; The passivation section includes a passivation cavity and a pre-vacuum cavity formed by a first partition; the pre-vacuum cavity is connected to a first vacuum device; the passivation cavity is used to place the perovskite wet film to be passivated. The passivation gas generator is connected to the second vacuum pumping device and has a heating device inside; the passivation gas generator is used to provide passivation gas to the passivation unit.

9. The passivation apparatus according to claim 8, characterized in that, The passivation device includes a passivation gas generating section, a passivation chamber, and a pre-extraction chamber, which run from bottom to top. A first partition is movably disposed between the passivation cavity and the pre-extraction cavity, and the first partition separates or connects the passivation cavity and the pre-extraction cavity; The passivation gas generating unit includes a passivation vapor chamber, and a second partition is movably disposed between the passivation vapor chamber and the passivation chamber. The second partition separates or connects the passivation chamber and the passivation vapor chamber. The passivation cavity is provided with an opening and closing door for picking up and putting in the substrate.

10. The passivation apparatus according to claim 8, characterized in that, The passivation cavity is equipped with a heating plate for supporting and heating the substrate.

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