Method for passivating perovskite thin films, passivated perovskite thin films and perovskite cells

Abstract

This invention relates to a passivation method for perovskite thin films, passivated perovskite thin films, and perovskite solar cells. The passivation method includes the following steps: the surface of the perovskite thin film is sequentially subjected to gas-phase passivation and liquid-phase passivation; the passivation gas used in the gas-phase passivation includes halides and / or sulfides; the passivating agent solution used in the liquid-phase passivation includes Lewis acid passivating agents. The passivation method of this invention first uses gas-phase passivation to reduce surface site defects, thus reducing the impact of subsequent liquid-phase passivation on the surface composition distribution; the Lewis acid passivating agent can accept electrons from iodide ions and increase the migration barrier of iodide ions; therefore, the passivation method provided by this invention solves the problem of uncontrollable solvent evaporation. Performing liquid-phase passivation on the surface of the perovskite thin film after gas-phase passivation can avoid damage to the perovskite structure and reduce non-radiative recombination, thereby obtaining high-quality passivated perovskite thin films and perovskite solar cells with superior performance.

Description

Technical Field

[0001] This invention belongs to the field of solar energy technology and relates to a perovskite battery, particularly to a passivation method for a perovskite thin film, a passivated perovskite thin film, and a perovskite battery. Background Technology

[0002] Perovskite solar cells (PSCs) possess unique semiconductor properties, such as strong light absorption, excellent defect tolerance, and long carrier lifetime, but stability issues remain before commercialization. The stability of perovskite solar cells is directly related to ionic defects, and improved stability is inextricably linked to reduced halide ion migration. The ionic nature of perovskite solar cells and the evaporation of organic components during annealing are the main causes of defects in perovskite films. Furthermore, poor stability is also attributed to the low electronegativity of iodine, which exacerbates ion migration, ultimately leading to a decrease in the device's photoelectric conversion efficiency and stability.

[0003] Trapped states at the perovskite film interface significantly influence nonradiative carrier recombination, and widely used solvent-based passivation methods suffer from disrupted compositional distribution. Applying solvents directly to the perovskite film surface disrupts the surface compositional distribution, leading to uncertainty in defect types and quantities, and consequently, poor device repeatability. Vapor-phase passivation, on the other hand, relies on the evaporation of the precursor solution. Uncontrollable evaporation rates, low vapor purity, and vapor escape rates during evaporation reduce the consistency and reliability of vapor-phase passivation.

[0004] Therefore, there is a need to provide a passivation method for perovskite thin films that can improve photoelectric conversion efficiency and stability, as well as a passivated perovskite thin film and a perovskite cell. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a passivation method for perovskite thin films, a passivated perovskite thin film, and a perovskite battery. The passivation method can solve the problems that using solvents will damage the surface composition of perovskite thin films and that it is difficult to control the evaporation rate in gas phase passivation. It can obtain high-quality passivated perovskite thin films and perovskite batteries with better performance.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a passivation method for perovskite thin films, the passivation method comprising the following steps:

[0008] The surface of the perovskite thin film is subjected to gas-phase passivation and liquid-phase passivation in sequence.

[0009] The passivation gases used in the gas-phase passivation include halides and / or sulfides.

[0010] The passivating agent solution used in the liquid-phase passivation includes Lewis acid passivating agents.

[0011] The passivation method of this invention first uses vapor-phase passivation to reduce surface site defects, thereby reducing the impact of subsequent liquid-phase passivation on the surface composition distribution. Lewis acid passivating agents can accept electrons from iodide ions and increase the migration barrier of iodide ions. Therefore, the passivation method provided by this invention solves the problem of uncontrollable solvent evaporation. Liquid-phase passivation of the perovskite film surface after vapor-phase passivation can avoid damage to the perovskite structure and reduce non-radiative recombination, thereby obtaining high-quality passivated perovskite films and perovskite solar cells with better performance.

[0012] Preferably, the passivation gas used for the gas-phase passivation includes any one or a combination of at least two of sulfur-containing gases, ammonia, or hydrogen halides.

[0013] Preferably, the vapor-phase passivation includes: heating ammonium halide under vacuum conditions to generate passivation gas, and performing vapor-phase passivation on the surface of the perovskite film.

[0014] Preferably, the ammonium halide includes any one or a combination of at least two of ammonium fluoride, ammonium bromide, or ammonium iodide.

[0015] Preferably, the gas phase passivation time is 15 min to 30 min.

[0016] Preferably, the Lewis acid passivating agent includes any one or a combination of at least two of boric acid, boron trifluoride, aluminum salt, or ferrous salt; the aluminum salt includes any one or a combination of at least two of aluminum chloride, aluminum silicate, or aluminum nitrate; and the ferrous salt includes any one or a combination of at least two of ferrous chloride, ferrous sulfate, or ferrous nitrate.

[0017] Preferably, the concentration of the passivating agent in the passivating agent solution is 0.1 mg / mL to 0.5 mg / mL.

[0018] Preferably, the liquid-phase passivation includes: coating the surface of the perovskite film after gas-phase passivation with a passivating agent solution, purging the solvent, and then annealing.

[0019] Preferably, the coating method includes scraping at a speed of 15 mm / s to 18 mm / s.

[0020] Preferably, the annealing includes a first annealing and a second annealing performed sequentially; the temperature of the first annealing is 70℃-80℃ and the time is more than 1 minute; the temperature of the second annealing is 110℃-130℃ and the time is more than 10 minutes.

[0021] In a second aspect, the present invention provides a passivated perovskite film, wherein the passivated perovskite film is obtained by passivation using the passivation method described in the first aspect.

[0022] Thirdly, the present invention provides a perovskite solar cell, the perovskite solar cell comprising a transparent conductive substrate, a first carrier transport layer, a passivated perovskite thin film as described in the second aspect, a second carrier transport layer and an electrode layer stacked together.

[0023] When the first carrier transport layer is a hole transport layer, the second carrier transport layer is an electron transport layer.

[0024] When the first carrier transport layer is an electron transport layer, the second carrier transport layer is a hole transport layer.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The passivation method of this invention first uses vapor-phase passivation to reduce surface site defects, thereby reducing the impact of subsequent liquid-phase passivation on the surface composition distribution. Lewis acid passivating agents can accept electrons from iodide ions and increase the migration barrier of iodide ions. Therefore, the passivation method provided by this invention solves the problem of uncontrollable solvent evaporation. Liquid-phase passivation of the perovskite film surface after vapor-phase passivation can avoid damage to the perovskite structure and reduce non-radiative recombination, thereby obtaining high-quality passivated perovskite films and perovskite solar cells with better performance. Attached Figure Description

[0027] Figure 1 The efficiency graphs are for the perovskite solar cells in Examples 1-6 and Comparative Examples 1-5. Detailed Implementation

[0028] 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.

[0029] An embodiment of the present invention provides a passivation method for perovskite thin films, the passivation method comprising the following steps:

[0030] The surface of the perovskite thin film is subjected to gas-phase passivation and liquid-phase passivation in sequence.

[0031] The passivation gases used in the gas-phase passivation include halides and / or sulfides.

[0032] The passivating agent solution used in the liquid-phase passivation includes Lewis acid passivating agents.

[0033] The passivation method of this invention first uses vapor-phase passivation to reduce surface site defects, thereby reducing the impact of subsequent liquid-phase passivation on the surface composition distribution. Lewis acid passivating agents can accept electrons from iodide ions and increase the migration barrier of iodide ions. Therefore, the passivation method provided by this invention solves the problem of uncontrollable solvent evaporation. Liquid-phase passivation of the perovskite film surface after vapor-phase passivation can avoid damage to the perovskite structure and reduce non-radiative recombination, thereby obtaining high-quality passivated perovskite films and perovskite solar cells with better performance.

[0034] In some embodiments, the passivation gas used for the gas-phase passivation includes any one or a combination of at least two of sulfur-containing gases, ammonia, or hydrogen halides. Typical but non-limiting combinations include combinations of sulfur-containing gases and ammonia, ammonia and hydrogen chloride, sulfur-containing gases and hydrogen chloride, or sulfur-containing gases, ammonia, and hydrogen halides.

[0035] Optionally, the sulfur-containing gas includes hydrogen sulfide and / or carbon disulfide.

[0036] Optionally, the hydrogen halide includes any one or a combination of at least two of hydrogen fluoride, hydrogen bromide, or hydrogen iodide. Typical but non-limiting combinations include combinations of hydrogen fluoride and hydrogen bromide, combinations of hydrogen bromide and hydrogen iodide, combinations of hydrogen fluoride and hydrogen iodide, or combinations of hydrogen fluoride, hydrogen bromide, and hydrogen iodide.

[0037] In some embodiments, the passivation gas used for gas-phase passivation is a combination of ammonia and hydrogen halide. More preferably, the passivation gas used for gas-phase passivation is obtained by decomposing ammonium halide.

[0038] For example, when the passivation gas used in the gas-phase passivation is a combination of ammonia and hydrogen fluoride, the passivation gas is obtained by heating and decomposing ammonium fluoride; when the passivation gas used in the gas-phase passivation is a combination of ammonia and hydrogen bromide, the passivation gas is obtained by heating and decomposing ammonium bromide; when the passivation gas used in the gas-phase passivation is a combination of ammonia and hydrogen iodide, the passivation gas is obtained by heating and decomposing ammonium iodide.

[0039] In some embodiments, the vapor-phase passivation includes: heating ammonium halide under vacuum conditions to generate passivation gas, thereby performing vapor-phase passivation on the surface of the perovskite film.

[0040] As a further preferred technical solution, the vapor phase passivation includes: placing a perovskite film above a vacuum fumigation chamber, with the perovskite film facing downwards towards a heating stage; placing ammonium halide on the heating stage, and evacuating to a vacuum level of 1×10⁻⁶. -2 Below Pa; the heating stage heats up to decompose ammonium halide, and the surface of the perovskite film is passivated by controlling the thermal evaporation time.

[0041] In some embodiments, the ammonium halide includes any one or a combination of at least two of ammonium fluoride, ammonium bromide, or ammonium iodide. Typical but non-limiting combinations include a combination of ammonium fluoride and ammonium bromide, a combination of ammonium fluoride and ammonium iodide, a combination of ammonium bromide and ammonium iodide, or a combination of ammonium fluoride, ammonium bromide, and ammonium iodide, preferably ammonium fluoride.

[0042] The temperature of the heating platform needs to be high enough to allow the ammonium halide to decompose. Taking ammonium fluoride as an example, the temperature of the heating platform is 110℃-130℃, such as 110℃, 115℃, 120℃, 125℃ or 130℃, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0043] The passivation time affects the passivation effect. Too short a passivation time will not achieve sufficient passivation, while too long a passivation time will over-etch the surface of the perovskite film and damage its composition. Therefore, the passivation time needs to be optimized.

[0044] In some embodiments, the gas phase passivation time is 15 min to 30 min, for example, it can be 15 min, 16 min, 18 min, 20 min, 24 min, 25 min, 28 min or 30 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0045] In some embodiments, the Lewis acid passivating agent includes any one or a combination of at least two of boric acid (H3BO3), boron trifluoride (BF3), aluminum salts, or ferrous salts. Typical but non-limiting combinations include combinations of boric acid and boron trifluoride, combinations of boron trifluoride and aluminum salts, combinations of aluminum salts and ferrous salts, combinations of boric acid, boron trifluoride, and aluminum salts, or combinations of boric acid, boron trifluoride, aluminum salts, and ferrous salts, preferably boric acid.

[0046] The aluminum salt includes any one or a combination of at least two of aluminum chloride (AlCl3), aluminum silicate (Al2SiO5), or aluminum nitrate (Al(NO3)3). Typical but non-limiting combinations include combinations of aluminum chloride and aluminum silicate, combinations of aluminum silicate and aluminum nitrate, combinations of aluminum chloride and aluminum nitrate, or combinations of aluminum chloride, aluminum silicate, and aluminum nitrate.

[0047] The ferrous salt includes any one or a combination of at least two of ferrous chloride (FeCl2), ferrous sulfate (FeSO4), or ferrous nitrate (Fe(NO3)2). Typical but non-limiting combinations include combinations of ferrous chloride and ferrous sulfate, ferrous sulfate and ferrous nitrate, ferrous chloride and ferrous nitrate, or combinations of ferrous chloride, ferrous sulfate, and ferrous nitrate.

[0048] Boric acid, as a Lewis acid passivating agent, has sp2 hybridized boron atoms that can easily accept electrons from iodide ions into their empty non-hybridized p orbitals. The formation of Pb-O bonds further increases the migration barrier of iodide ions.

[0049] As a further preferred technical solution, the passivating gases used in gas-phase passivation are NH3 and HF, and the Lewis acid passivating agent used in liquid-phase passivation is boric acid. By combining specific passivating gases with specific Lewis acid passivating agents, the problem of uncontrollable solvent evaporation can be better solved, resulting in perovskite thin films of higher quality and perovskite batteries with better performance.

[0050] In some embodiments, the concentration of the passivating agent in the passivating agent solution is 0.1 mg / mL to 0.5 mg / mL, for example, it can be 0.1 mg / mL, 0.15 mg / mL, 0.2 mg / mL, 0.25 mg / mL, 0.3 mg / mL, 0.35 mg / mL, 0.4 mg / mL, 0.45 mg / mL or 0.5 mg / mL, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0051] In some embodiments, the solvent of the passivating agent solution includes isopropanol and / or trifluoroethanol.

[0052] In some embodiments, the liquid-phase passivation includes: coating the surface of the perovskite film after gas-phase passivation with a passivating agent solution, purging the solvent, and then annealing.

[0053] In some embodiments, the purging solvent is nitrogen and / or an inert gas.

[0054] In some embodiments, the coating method includes scraping at a speed of 8 mm / s to 12 mm / s, for example, 8 mm / s, 9 mm / s, 10 mm / s, 11 mm / s or 12 mm / s, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0055] As a preferred technical solution, gradient annealing can delay crystallization and improve the crystallization quality of perovskite films.

[0056] In some embodiments, the annealing includes a first annealing and a second annealing performed sequentially; the temperature of the first annealing is 70°C-80°C and the time is more than 1 minute; the temperature of the second annealing is 110°C-130°C and the time is more than 10 minutes.

[0057] The temperature of the first annealing is 70℃-80℃, for example, it can be 70℃, 72℃, 75℃, 78℃ or 80℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0058] The first annealing time is 1 minute or more, for example, it can be 1 minute, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 8 minutes or 10 minutes, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0059] The second annealing temperature is 110℃-130℃, for example, it can be 110℃, 115℃, 120℃, 125℃ or 130℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0060] The second annealing time is 10 minutes or more, for example, it can be 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 32 minutes, 35 minutes, 38 minutes or 40 minutes, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0061] In some embodiments, the perovskite film is made of ABX3 type perovskite, where A is Cs. + Ru + MA + (MA + CH3NH3 + C(NH2)3 + FA + (FA + CH(NH2)2 + Any one or at least two of the following, for example, could be Cs + With K + The combination of CH3NH3 + C(NH2)3 + With CH(NH2)2 + Combination, Cs + K + Ru + With CH3NH3 + Combinations, or Cs + K + Ru + CH3NH3 + C(NH2)3 + With CH(NH2)2 + The combination; B is Pb 2+ and / or Sn 2+ X is Br - I - or Cl - Any one or at least two of the above, typical but non-limiting combinations include Br - with I- The combination, I - With Cl - The combination, Br - With Cl - The combination, or Br - I - With Cl - The combination of .

[0062] In some embodiments, the thickness of the perovskite film is from 300 nm to 600 nm, for example, it can be 300 nm, 350 nm, 400 nm, 450 nm, 480 nm, 500 nm, 520 nm, 550 nm, 560 nm, 580 nm or 600 nm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0063] One embodiment of the present invention provides a passivated perovskite film, which is obtained by passivation using the passivation method described in any embodiment.

[0064] Thirdly, the present invention provides a perovskite solar cell, the perovskite solar cell comprising a transparent conductive substrate, a first carrier transport layer, a passivated perovskite thin film as described in the second aspect, a second carrier transport layer and an electrode layer stacked together.

[0065] When the first carrier transport layer is a hole transport layer, the second carrier transport layer is an electron transport layer.

[0066] When the first carrier transport layer is an electron transport layer, the second carrier transport layer is a hole transport layer.

[0067] In some embodiments, the perovskite solar cell includes a transparent conductive substrate, a hole transport layer, a passivated perovskite thin film, an electron transport layer, and an electrode layer stacked sequentially.

[0068] In some embodiments, the transparent conductive substrate is made of fluorine-doped indium oxide (FTO) or indium tin oxide (ITO).

[0069] In some embodiments, the hole transport layer is made of any one or a combination of at least two of nickel oxide, aluminum oxide, styrene sulfonate, polytriarylamine, or cuprous thiocyanate. Typical but non-limiting combinations include combinations of nickel oxide and aluminum oxide, combinations of styrene sulfonate and polytriarylamine, combinations of polytriarylamine and cuprous thiocyanate, combinations of nickel oxide, aluminum oxide, and styrene sulfonate, combinations of aluminum oxide, styrene sulfonate, polytriarylamine, and cuprous thiocyanate, or combinations of nickel oxide, aluminum oxide, styrene sulfonate, polytriarylamine, and cuprous thiocyanate.

[0070] In some embodiments, the thickness of the hole transport layer is 5nm-15nm, for example, it can be 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 12nm or 15nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0071] In some embodiments, the electron transport layer is made of fullerene and / or 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

[0072] In some embodiments, the thickness of the electron transport layer is 5nm-20nm, for example, it can be 5nm, 8nm, 10nm, 12nm, 15nm, 18nm or 20nm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0073] In some embodiments, the electrode layer is made of metal and / or conductive non-metal.

[0074] The metal includes, but is not limited to, any one or a combination of at least two of copper, silver, or gold.

[0075] The conductive nonmetal includes, but is not limited to, any one or a combination of at least two of transparent conductive oxides, conductive polymers, or carbon.

[0076] In some embodiments, the thickness of the electrode layer is 100 nm to 120 nm, for example, it can be 100 nm, 105 nm, 110 nm, 115 nm or 120 nm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0077] Example 1

[0078] This embodiment provides a perovskite solar cell, comprising a transparent conductive substrate, a hole transport layer, a passivated perovskite thin film, an electron transport layer, and an electrode layer sequentially stacked. The fabrication method includes the following steps:

[0079] (1) After ultrasonic cleaning of a 30cm×30cm FTO transparent conductive substrate, it was dried with nitrogen gas; after ultraviolet treatment, a nickel oxide hole transport layer with a thickness of 10nm was deposited by magnetron sputtering.

[0080] (2) A perovskite precursor solution was coated onto the surface of the nickel oxide hole transport layer, and after annealing, a material of Cs was obtained. 0.1 FA 0.9 PbI3 perovskite thin films;

[0081] (3) The perovskite film is placed above the vacuum fumigation chamber, with the perovskite film facing the heating stage placed below; NH4F is placed on the heating stage, and the vacuum is evacuated to 1×10⁻⁶. -2 Pa; The heating stage is heated to 110℃ to decompose NH4F into NH3 and HF. The thermal evaporation time is controlled to be 15min to perform vapor phase passivation on the surface of the perovskite film, and the perovskite film after vapor phase passivation is obtained.

[0082] (4) Cut the perovskite film after vapor phase passivation into 5cm×5cm size, add 30μL of 0.3mg / mL isopropanol borate solution; scrape at a scraping speed of 10mm / s, then blow away excess solvent with nitrogen, first anneal at 75℃ for 1min, then anneal at 120℃ for 10min to obtain a passivated perovskite film with a thickness of 380nm.

[0083] (5) At an absolute pressure of 1×10 -6 Under the condition of Pa, a BCP layer with a thickness of 10 nm and a copper electrode with a thickness of 110 nm were deposited by vapor deposition to obtain a perovskite solar cell.

[0084] Example 2

[0085] This embodiment provides a perovskite battery, which is the same as that in Embodiment 1 except that the thermal evaporation time in step (3) is 20 min.

[0086] Example 3

[0087] This embodiment provides a perovskite battery, which is the same as that in Embodiment 1 except that the thermal evaporation time in step (3) is 30 min.

[0088] Example 4

[0089] This embodiment provides a perovskite battery, which is the same as that in Embodiment 1 except that the heating stage is heated to 130°C in step (3).

[0090] Example 5

[0091] This embodiment provides a perovskite battery, except that the heating stage is heated to 130°C in step (3) and the thermal evaporation time is 20 min, the rest is the same as in embodiment 1.

[0092] Example 6

[0093] This embodiment provides a perovskite battery, except that the heating stage is heated to 130°C in step (3) and the heat evaporation time is 30 min, the rest is the same as in embodiment 1.

[0094] Example 7

[0095] This embodiment provides a perovskite battery, which is the same as in Example 5 except that the boric acid in the isopropanol borate solution is replaced with boron trifluoride by mass.

[0096] Example 8

[0097] This embodiment provides a perovskite solar cell, comprising a transparent conductive substrate, a hole transport layer, a passivated perovskite thin film, an electron transport layer, and an electrode layer sequentially stacked. The fabrication method includes the following steps:

[0098] (1) After ultrasonic cleaning of a 30cm×30cm FTO transparent conductive substrate, it was dried with nitrogen gas; after ultraviolet treatment, a nickel oxide hole transport layer with a thickness of 10nm was deposited by magnetron sputtering.

[0099] (2) A perovskite precursor solution was coated onto the surface of the nickel oxide hole transport layer, and after annealing, a material of Cs was obtained. 0.1 FA 0.9 PbI3 perovskite thin films;

[0100] (3) The perovskite film is placed above the vacuum fumigation chamber, with the perovskite film facing the heating stage placed below; NH4F is placed on the heating stage, and the vacuum is evacuated to 1×10⁻⁶. -2 Pa; The heating stage is heated to 110℃ to decompose NH4F into NH3 and HF. The thermal evaporation time is controlled to be 30min to perform vapor phase passivation on the surface of the perovskite film, and the perovskite film after vapor phase passivation is obtained.

[0101] (4) Cut the perovskite film after vapor phase passivation into 5cm×5cm size, add 30μL of 0.1mg / mL isopropanol borate solution; scrape at a scraping speed of 8mm / s, then blow away excess solvent with nitrogen, first anneal at 70℃ for 1min, then anneal at 110℃ for 10min to obtain a passivated perovskite film with a thickness of 380nm.

[0102] (5) At an absolute pressure of 1×10 -6 Under the condition of Pa, a BCP layer with a thickness of 10 nm and a copper electrode with a thickness of 110 nm were deposited by vapor deposition to obtain a perovskite solar cell.

[0103] Example 9

[0104] This embodiment provides a perovskite solar cell, comprising a transparent conductive substrate, a hole transport layer, a passivated perovskite thin film, an electron transport layer, and an electrode layer sequentially stacked. The fabrication method includes the following steps:

[0105] (1) After ultrasonic cleaning of a 30cm×30cm FTO transparent conductive substrate, it was dried with nitrogen gas; after ultraviolet treatment, a nickel oxide hole transport layer with a thickness of 10nm was deposited by magnetron sputtering.

[0106] (2) A perovskite precursor solution was coated onto the surface of the nickel oxide hole transport layer, and after annealing, a material of Cs was obtained. 0.1 FA 0.9 PbI3 perovskite thin films;

[0107] (3) The perovskite film is placed above the vacuum fumigation chamber, with the perovskite film facing the heating stage placed below; NH4F is placed on the heating stage, and the vacuum is evacuated to 1×10⁻⁶. -2 Pa; The heating stage is heated to 110℃ to decompose NH4F into NH3 and HF. The thermal evaporation time is controlled to be 30min to perform vapor phase passivation on the surface of the perovskite film, and the perovskite film after vapor phase passivation is obtained.

[0108] (4) Cut the perovskite film after vapor phase passivation into 5cm×5cm size, add 30μL of 0.5mg / mL isopropanol borate solution; scrape at a scraping speed of 12mm / s, then blow away excess solvent with nitrogen, first anneal at 80℃ for 1min, then anneal at 130℃ for 10min to obtain a passivated perovskite film with a thickness of 380nm.

[0109] (5) At an absolute pressure of 1×10 -6 Under the condition of Pa, a BCP layer with a thickness of 10 nm and a copper electrode with a thickness of 110 nm were deposited by vapor deposition to obtain a perovskite solar cell.

[0110] Comparative Example 1

[0111] This comparative example provides a perovskite solar cell, comprising a transparent conductive substrate, a hole transport layer, a passivated perovskite thin film, an electron transport layer, and an electrode layer sequentially stacked thereon. The fabrication method includes the following steps:

[0112] (1) After ultrasonic cleaning of a 30cm×30cm FTO transparent conductive substrate, it was dried with nitrogen gas; after ultraviolet treatment, a nickel oxide hole transport layer with a thickness of 10nm was deposited by magnetron sputtering.

[0113] (2) A perovskite precursor solution was coated onto the surface of the nickel oxide hole transport layer, and after annealing, a material of Cs was obtained. 0.1 FA 0.9 PbI3 perovskite thin films;

[0114] (3) The perovskite film is placed above the vacuum fumigation chamber, with the perovskite film facing the heating stage placed below; the vacuum is evacuated to 1×10⁻⁶.-2 Pa, NH3 was directly introduced into the vacuum fumigation chamber and the fumigation time was controlled to be 15 min to perform vapor phase passivation on the surface of the perovskite film, resulting in a passivated perovskite film with a thickness of 380 nm.

[0115] (4) At an absolute pressure of 1×10 -6 Under the condition of Pa, a BCP layer with a thickness of 10 nm and a copper electrode with a thickness of 110 nm were deposited by vapor deposition to obtain a perovskite solar cell.

[0116] Comparative Example 2

[0117] This comparative example provides a perovskite solar cell, comprising a transparent conductive substrate, a hole transport layer, a passivated perovskite thin film, an electron transport layer, and an electrode layer sequentially stacked thereon. The fabrication method includes the following steps:

[0118] (1) After ultrasonic cleaning of a 30cm×30cm FTO transparent conductive substrate, it was dried with nitrogen gas; after ultraviolet treatment, a nickel oxide hole transport layer with a thickness of 10nm was deposited by magnetron sputtering.

[0119] (2) A perovskite precursor solution was coated onto the surface of the nickel oxide hole transport layer, and after annealing, a material of Cs was obtained. 0.1 FA 0.9 PbI3 perovskite thin films;

[0120] (3) The perovskite film is placed above the vacuum fumigation chamber, with the perovskite film facing the heating stage placed below; NH4F is placed on the heating stage, and the vacuum is evacuated to 1×10⁻⁶. -2 Pa; The heating stage is heated to 130℃ to decompose NH4F into NH3 and HF. The thermal evaporation time is controlled to be 20min to perform vapor phase passivation on the surface of the perovskite film, and the perovskite film after vapor phase passivation is obtained; by annealing at 100℃ for 5min, NH3 escapes and only the effect of HF gas is retained, and a passivated perovskite film with a thickness of 380nm is obtained.

[0121] (4) At an absolute pressure of 1×10 -6 Under the condition of Pa, a BCP layer with a thickness of 10 nm and a copper electrode with a thickness of 110 nm were deposited by vapor deposition to obtain a perovskite solar cell.

[0122] Comparative Example 3

[0123] This comparative example provides a perovskite solar cell, comprising a transparent conductive substrate, a hole transport layer, a passivated perovskite thin film, an electron transport layer, and an electrode layer sequentially stacked thereon. The fabrication method includes the following steps:

[0124] (1) After ultrasonic cleaning of a 30cm×30cm FTO transparent conductive substrate, it was dried with nitrogen gas; after ultraviolet treatment, a nickel oxide hole transport layer with a thickness of 10nm was deposited by magnetron sputtering.

[0125] (2) A perovskite precursor solution was coated onto the surface of the nickel oxide hole transport layer, and after annealing, a material of Cs was obtained. 0.1 FA 0.9 PbI3 perovskite thin films;

[0126] (3) The perovskite film is placed above the vacuum fumigation chamber, with the perovskite film facing the heating stage placed below; NH4F is placed on the heating stage, and the vacuum is evacuated to 1×10⁻⁶. -2 Pa; The heating stage is heated to 130℃ to decompose NH4F into NH3 and HF. The thermal evaporation time is controlled to be 20min to passivate the surface of the perovskite film in the vapor phase, resulting in a passivated perovskite film with a thickness of 380nm.

[0127] (4) At an absolute pressure of 1×10 -6 Under the condition of Pa, a BCP layer with a thickness of 10 nm and a copper electrode with a thickness of 110 nm were deposited by vapor deposition to obtain a perovskite solar cell.

[0128] Comparative Example 4

[0129] This comparative example provides a perovskite solar cell, comprising a transparent conductive substrate, a hole transport layer, a passivated perovskite thin film, an electron transport layer, and an electrode layer sequentially stacked thereon. The fabrication method includes the following steps:

[0130] (1) After ultrasonic cleaning of a 30cm×30cm FTO transparent conductive substrate, it was dried with nitrogen gas; after ultraviolet treatment, a nickel oxide hole transport layer with a thickness of 10nm was deposited by magnetron sputtering.

[0131] (2) A perovskite precursor solution was coated onto the surface of the nickel oxide hole transport layer, and after annealing, a material of Cs was obtained. 0.1 FA 0.9 PbI3 perovskite thin films;

[0132] (3) Cut the perovskite film into 5cm×5cm size, add 30μL of 0.2mg / mL isopropanol borate solution; scrape at a scraping speed of 16mm / s, then blow away excess solvent with nitrogen, first anneal at 75℃ for 1min, then anneal at 120℃ for 10min to obtain a passivated perovskite film with a thickness of 380nm.

[0133] (4) At an absolute pressure of 1×10 -6Under the condition of Pa, a BCP layer with a thickness of 10 nm and a copper electrode with a thickness of 110 nm were deposited by vapor deposition to obtain a perovskite solar cell.

[0134] Comparative Example 5

[0135] This comparative example provides a perovskite solar cell, comprising a transparent conductive substrate, a hole transport layer, a perovskite thin film, an electron transport layer, and an electrode layer sequentially stacked thereon. The fabrication method includes the following steps:

[0136] (1) After ultrasonic cleaning of a 30cm×30cm FTO transparent conductive substrate, it was dried with nitrogen gas; after ultraviolet treatment, a nickel oxide hole transport layer with a thickness of 10nm was deposited by magnetron sputtering.

[0137] (2) A perovskite precursor solution was coated onto the surface of the nickel oxide hole transport layer, and after annealing, a material of Cs was obtained. 0.1 FA 0.9 PbI3, a perovskite thin film with a thickness of 380 nm;

[0138] (3) At an absolute pressure of 1×10 -6 Under the condition of Pa, a BCP layer with a thickness of 10 nm and a copper electrode with a thickness of 110 nm were deposited by vapor deposition to obtain a perovskite solar cell.

[0139] Performance Characterization

[0140] The perovskite solar cells provided in the above embodiments and comparative examples were tested, including current-voltage tests under standard sunlight with a light intensity of 100 mW / cm². 2 The testing instruments included conventional solar simulators and digital source meters, and the photovoltaic parameters tested included circuit current density (Jsc, mA / cm²). 2 The open-circuit voltage (Voc, V), photoelectric conversion efficiency (PCE, %), and fill factor (FF, %) were tested, and the results are shown in Table 1. As can be seen from Table 1, the battery efficiency of the embodiment is significantly improved compared to the comparative example.

[0141] Table 1

[0142]

[0143]

[0144] Stability tests were conducted on the perovskite solar cells provided in the above embodiments and comparative examples. The test conditions were: aging tests were performed on the unencapsulated devices under conditions of 40±5% humidity and 25°C. The results are as follows: Figure 1As shown in the figure, the efficiency of the unpassivated standard device in Comparative Example 5 decreased most significantly, dropping to approximately 0.55 after 1000 hours, far lower than the other examples. Through gas / liquid phase dual passivation, the efficiency decrease in Examples 1-9 was relatively small, and remained above 0.85 for 1000 hours, demonstrating good stability. Comparative Examples 1-4, which used only one passivation method, also showed improved stability compared to the standard device, but not as significantly as the dual passivation effect. Figure 1 The results show that gas / liquid phase dual passivation has a better effect on improving device stability.

[0145] In summary, the passivation method of this invention first uses vapor-phase passivation to reduce surface site defects, thereby reducing the impact of subsequent liquid-phase passivation on the surface composition distribution. Lewis acid passivating agents can accept electrons from iodide ions and increase the migration barrier of iodide ions. Therefore, the passivation method provided by this invention solves the problem of uncontrollable solvent evaporation. Liquid-phase passivation of the perovskite film surface after vapor-phase passivation can avoid damage to the perovskite structure and reduce non-radiative recombination, thereby obtaining high-quality passivated perovskite films and perovskite solar cells with better performance.

[0146] The applicant declares that 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 passivation method for perovskite thin films, characterized in that, The passivation method includes the following steps: The surface of the perovskite thin film is sequentially subjected to vapor phase passivation and liquid phase passivation; The passivation gas used in the gas phase passivation includes halides and / or sulfides; The passivating agent solution used in the liquid-phase passivation includes Lewis acid passivating agents.

2. The passivation method according to claim 1, characterized in that, The passivation gas used in the gas phase passivation includes any one or a combination of at least two of sulfur-containing gases, ammonia, or hydrogen halides.

3. The passivation method according to claim 1, characterized in that, The vapor-phase passivation includes: heating ammonium halide under vacuum conditions to generate passivation gas, and then performing vapor-phase passivation on the surface of the perovskite film.

4. The passivation method according to claim 3, characterized in that, The ammonium halide includes any one or a combination of at least two of ammonium fluoride, ammonium bromide or ammonium iodide; And / or, the gas phase passivation time is 15 min-30 min.

5. The passivation method according to any one of claims 1-4, characterized in that, The Lewis acid passivating agent includes any one or a combination of at least two of boric acid, boron trifluoride, aluminum salt or ferrous salt; The aluminum salt includes any one or a combination of at least two of aluminum chloride, aluminum silicate, or aluminum nitrate. The ferrous salt includes any one or a combination of at least two of ferrous chloride, ferrous sulfate, or ferrous nitrate.

6. The passivation method according to claim 5, characterized in that, The passivating agent concentration in the passivating agent solution is 0.1 mg / mL to 0.5 mg / mL.

7. The passivation method according to claim 1, characterized in that, The liquid-phase passivation includes: coating the surface of the perovskite film after gas-phase passivation with a passivating agent solution, purging the solvent, and then annealing.

8. The passivation method according to claim 7, characterized in that, The coating method includes scraping at a speed of 8 mm / s-12 mm / s; And / or, the annealing includes a first annealing and a second annealing performed sequentially; the temperature of the first annealing is 70℃-80℃ and the time is more than 1 minute; the temperature of the second annealing is 110℃-130℃ and the time is more than 10 minutes.

9. A passivated perovskite thin film, characterized in that, The passivated perovskite film is obtained by passivation using the passivation method described in any one of claims 1-8.

10. A perovskite solar cell, characterized in that, The perovskite solar cell includes a transparent conductive substrate, a first carrier transport layer, a passivated perovskite thin film as described in claim 9, a second carrier transport layer, and an electrode layer stacked together. When the first carrier transport layer is a hole transport layer, the second carrier transport layer is an electron transport layer; When the first carrier transport layer is an electron transport layer, the second carrier transport layer is a hole transport layer.

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