Preparation method of perovskite solar cell based on gas phase assistance

Abstract

The invention belongs to the field of perovskite solar cells, provides a preparation method of a perovskite solar cell based on gas phase assistance, and aims to solve the problem of low photoelectric conversion efficiency of the perovskite solar cell due to the fact that an inorganic frame layer of a bottom interface part cannot be converted into a perovskite material in the prior art. In the preparation process of the perovskite light absorption layer, the organic polar solvent gas molecular layer is formed on the upper surface of the inorganic frame layer in advance through steam fumigation, on one hand, organic polar solvent gas molecules reconstruct a compact thin film structure on the surface of the inorganic frame layer, the thin film morphology is loosened, a cation permeation channel is expanded, and the light absorption efficiency is improved; the deep penetration of cations is promoted; on the other hand, organic polar solvent gas molecules react with lead iodide to form an intermediate phase complex, the crystallization reaction of PbI2 and cations is delayed, the PbI2 interplanar spacing is increased, cation permeation is promoted, a more uniform and high-quality perovskite light absorption layer is formed, and finally the energy conversion efficiency of the perovskite solar cell is improved.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cells, specifically providing a method for preparing a perovskite solar cell based on gas phase assistance. Background Technology

[0002] Perovskite solar cells, as a third-generation photovoltaic material, have the advantages of simple fabrication process, wide spectral absorption range, and low cost. In perovskite solar cells, the perovskite light-absorbing layer is one of the key film layers. Currently, the preparation of the perovskite light-absorbing layer usually adopts a two-step method. First, lead iodide and cesium bromide are evaporated to form an inorganic framework layer. Then, a mixed organic cation precursor solution formed by methylammonium bromide (MABr), methylammonium chloride (MACl), formamidinium chloride (FACl), and formamidinium iodide (FAI) is spin-coated onto the inorganic framework layer. Finally, the perovskite light-absorbing layer is formed after high-temperature and humidity annealing.

[0003] However, due to the thick and dense inorganic framework layer, the perovskite undergoes a top-down crystallization process in the initial stage of spin coating. Methylammonium bromide (MABr), methylammonium chloride (MACl), formamidinium chloride (FACl), and formamidinium iodide (FAI) first form a denser perovskite capping layer on the surface of the inorganic framework layer. This perovskite layer severely hinders the further downward diffusion and penetration of methylammonium bromide (MABr) and formamidinium iodide (FAI), resulting in some inorganic framework layers failing to transform into perovskite material. Incomplete conversion of the bottom inorganic film leads to low photoelectric conversion efficiency in perovskite solar cells. To address this problem, this invention provides a method for fabricating perovskite solar cells based on vapor-phase assisted deposition. Summary of the Invention

[0004] The purpose of this invention is to provide a method for fabricating perovskite solar cells based on gas phase assistance, in order to solve the problem that the inorganic framework layer at the bottom interface cannot be converted into perovskite material in the prior art, resulting in low photoelectric conversion efficiency of perovskite solar cells.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for fabricating a gas-phase assisted perovskite solar cell, characterized by comprising the following steps:

[0007] Step 1: Use a conductive substrate and form a hole transport layer on the surface of the conductive substrate;

[0008] Step 2: An inorganic framework layer is deposited on the upper surface of the hole transport layer by vapor deposition;

[0009] Step 3: An organic polar solvent gas molecule layer is formed on the upper surface of the inorganic framework layer by steam fumigation based on organic polar solvent gas components;

[0010] Step 4: Form a perovskite precursor solution layer in the organic polar solvent gas molecule layer; formation;

[0011] Step 5: Perform high-temperature and humidity annealing on the stacked structure consisting of the inorganic framework layer, the organic polar solvent gas molecule layer, and the perovskite precursor solution layer to form a perovskite light-absorbing layer.

[0012] Step 6: Sequentially form an electron transport layer and a positive electrode on the surface of the perovskite light-absorbing layer to obtain a perovskite single-junction cell; or, sequentially form an electron transport layer, a buffer layer, a front composite layer, a positive electrode, and an anti-reflection layer on the surface of the perovskite light-absorbing layer, and form a back electrode on the back side of the conductive substrate to obtain a perovskite-silicon tandem cell.

[0013] Furthermore, the thickness ratio of the inorganic framework layer, the organic polar solvent gas molecule layer, and the perovskite precursor solution layer is (200~320):(1~2):(350~550).

[0014] Furthermore, the formation process of the inorganic framework layer is as follows:

[0015] Cesium bromide and lead iodide were vapor-deposited on the upper surface of the hole transport layer to form an inorganic framework layer. The evaporation rate of cesium bromide was 0.11–0.12 Å / s, and the evaporation rate of lead iodide was 1.08–1.09 Å / s. The vacuum degree for both was 9.5–9.9 × 10⁻⁶. -4 Pa.

[0016] Furthermore, the formation process of the organic polar solvent gas molecular layer is as follows:

[0017] In a sealed glove box with a relative humidity of 10-20%, 5-10 μL of organic polar solvent with a purity greater than 99% is placed on a heating stage and steamed at a temperature of 80-150°C to form a constant atmosphere. After steam fumigation for 5-20 minutes, an organic polar solvent gas molecule layer is formed on the upper surface of the inorganic framework layer.

[0018] Furthermore, the organic polar solvent is one or more of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP).

[0019] Furthermore, the formation process of the perovskite precursor solution layer is as follows:

[0020] Prepare a perovskite precursor solution, including: methylammonium bromide (MABr), methylammonium chloride (MACl), formamidinium chloride (FACl), and formamidinium iodide (FAI) and an organic solvent; set the spin coating speed to 3000~4000 rpm, the spin coating acceleration to 3000~4000 rpm / s, and the spin coating time to 25~30s.

[0021] Furthermore, in the perovskite precursor solution, the mass ratio of formamidinium iodide, methylammonium chloride, methylammonium bromide, and formamidinium chloride is 75~80:5.5~6.0:12~13:8~11.

[0022] Furthermore, the specific process of high-temperature and humidity annealing is as follows:

[0023] Set the high-temperature humidity annealing temperature to 150~170℃, the humidity to 50~75%, and the time to 25~30min.

[0024] Based on the above technical solution, the beneficial effects of the present invention are as follows:

[0025] This invention provides a method for fabricating a perovskite solar cell based on vapor phase assisted deposition. During the fabrication of the perovskite light-absorbing layer, an organic polar solvent gas molecule layer is pre-formed on the upper surface of the inorganic framework layer through steam fumigation. On one hand, the organic polar solvent gas molecules reconstruct the dense film structure on the surface of the inorganic framework layer, loosening the film morphology, expanding the cation penetration channels, and promoting deeper cation penetration. On the other hand, the organic polar solvent gas molecules can react with lead iodide to form an intermediate phase complex, delaying the crystallization reaction of PbI2 with cations and increasing the interplanar spacing of PbI2, promoting cation penetration to form a more uniform and high-quality perovskite light-absorbing layer, ultimately improving the energy conversion efficiency of the perovskite solar cell. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the perovskite single-junction solar cell provided by the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the perovskite tandem solar cell provided by the present invention;

[0028] Figure 3 This is a comparison of the XRD patterns of perovskite films in the embodiments and comparative examples of the present invention;

[0029] Figure 4 These are SEM images of the perovskite films in the embodiments and comparative examples of the present invention. Figure 4 Image (a) shows the bottom interface morphology of the perovskite film in Comparative Example 1 under a scanning electron microscope (SEM). Figure 4Image (b) shows the bottom interface morphology of the perovskite film in Example 1 under a scanning electron microscope (SEM). Figure 4 Image (c) shows the cross-sectional morphology of the perovskite film in Comparative Example 2 under a scanning electron microscope (SEM). Figure 4 Image d shows the cross-sectional morphology of the perovskite film in Example 2 under a scanning electron microscope (SEM).

[0030] In the above attached figures:

[0031] 1-Conductive substrate, 2-Hole transport layer, 3-Perovskite light-absorbing layer, 4-Electron transport layer, 5-Positive electrode, 6-Buffer layer, 7-Front composite layer, 8-Back electrode, 9-Antireflection layer. Detailed Implementation

[0032] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0033] This invention provides a method for fabricating a gas-phase assisted perovskite solar cell, wherein the fabricated perovskite solar cell can be as follows: Figure 1 The perovskite single-junction cell shown can also be as follows: Figure 2 The perovskite-silicon tandem solar cell shown.

[0034] The method for fabricating the gas-phase-assisted perovskite solar cell includes the following steps:

[0035] Step 1: Using a pre-cleaned conductive substrate 1, a hole transport layer 2 is formed on the surface of the conductive substrate 1;

[0036] Step 3: An inorganic framework layer is vapor-deposited on the upper surface of hole transport layer 2. Within 30 minutes after formation, an organic polar solvent gas molecule layer is formed by steam fumigation. This organic polar solvent atmosphere molecules that come into contact with the inorganic framework layer make the dense morphology of the inorganic framework layer loose and porous. Subsequently, a perovskite precursor solution layer is formed on the upper surface to promote the reaction between the perovskite precursor solution that has penetrated into the inorganic framework layer and PbI2 to generate perovskite material. The stacked structure is then subjected to high-temperature and humidity annealing to obtain perovskite light-absorbing layer 3.

[0037] Step 3: On the surface of the perovskite light-absorbing layer 3, an electron transport layer 4, a positive electrode 5, a buffer layer 6, a front composite layer 7, an anti-reflection layer 9, and a back electrode 8 on the back side of the conductive substrate are formed sequentially.

[0038] It should be noted that the conductive substrate 1 is a conductive glass substrate or a conductive silicon substrate. When the conductive substrate 1 is a conductive glass substrate, a perovskite single-junction cell is formed accordingly; when the conductive substrate 1 is a conductive silicon substrate, a perovskite-silicon tandem cell is formed accordingly.

[0039] Furthermore, the method for forming hole transport layer 2 includes the following steps:

[0040] The conductive substrate 1 is placed in the mask of the hole transport layer 2;

[0041] A nickel oxide layer was sputtered on the surface of the conductive substrate 1 using radio frequency magnetron sputtering, wherein the vacuum degree was 9.5~10.5×10⁻⁶. -4 Pa, sputtering power of 85~90W, argon flow rate of 18~25sccm, sputtering time of 8~15min;

[0042] A (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz) layer was spin-coated onto the surface of the nickel oxide layer, wherein the amount of 2PACz was 50~110μL, the spin-coating speed was 2800~3000rpm, the spin-coating acceleration was 2800~3000rpm / s, and the spin-coating time was 25~30s;

[0043] The conductive substrate 1 with spin-coated 2PACz layer is placed on a hot plate and annealed at 95~100℃ for 8~10 min to form hole transport layer 2.

[0044] Furthermore, the method for forming the perovskite light-absorbing layer 3 includes the following steps:

[0045] A stacked structure consisting of a conductive substrate 1 and a hole transport layer 2 is placed in a mask of a perovskite light-absorbing layer 3. Cesium bromide and lead iodide are then deposited to form an inorganic framework layer. The evaporation rate of cesium bromide in the inorganic framework layer is 0.11–0.12 Å / s, the evaporation rate of lead iodide is 1.08–1.09 Å / s, and the vacuum degree is 9.5–9.9 × 10⁻⁶. -4 Pa;

[0046] The stacked structure consisting of the conductive substrate 1 and the hole transport layer 2 was placed in a sealed glove box with a relative humidity of 10-20%. 5-10 μL of a selected polar solvent molecule with a purity of 99% was transferred and immersed in a precisely temperature-controlled heating stage. The solution was steam-fumigated at a temperature of 80-150°C to create a constant atmosphere. After processing in this way for 5-20 minutes, a layer of mixed organic polar solvent gas molecules was obtained. The organic polar solvent gas molecules were one or more of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP) in any proportion.

[0047] A perovskite precursor solution is spin-coated onto the surface of the inorganic framework layer to form a perovskite precursor solution layer, and a stacked structure is formed on the surface of the hole transport layer 2 accordingly. The perovskite precursor solution comprises formamidinium iodide (FAI), methylammonium chloride (MACl), methylammonium bromide (MABr), formamidinium chloride (FACl), and an organic solvent (e.g., anhydrous ethanol). The mass ratio of formamidinium iodide, methylammonium chloride, methylammonium bromide, and formamidinium chloride is 75~80:5.5~6.0:12~13, 8~11. The spin-coating speed is 3000~4000 rpm, the spin-coating acceleration is 3000~4000 rpm / s, and the spin-coating time is 25~30s.

[0048] The laminated structure is transferred to a hot stage for high-temperature and humidity annealing, which allows the perovskite precursor solution that has penetrated into the inorganic framework layer to react with PbI2 to generate perovskite material, thus obtaining a perovskite light-absorbing layer. The high-temperature and humidity annealing temperature is 150~170℃, the high-temperature and humidity annealing humidity is 50~75%, and the high-temperature and humidity annealing time is 20~30min (e.g., 30min).

[0049] Furthermore, the method for forming the electron transport layer 4 includes the following steps:

[0050] The stacked structure obtained in step 3 is placed in the mask of electron transport layer 4, and a lithium fluoride layer (LiF layer) and a graphene layer (C) are sequentially deposited on the surface of perovskite light-absorbing layer 3. 60 The deposition consisted of a 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline layer and a 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline layer (BCP layer), with deposition rates of 0.09–0.12 Å / s and vacuum levels of 9.5–10.5 × 10⁻⁶. -4 Pa, the thickness of the lithium fluoride layer is 0.8~1.2 nm, the thickness of the graphene layer is 8~12 nm, and the thickness of the 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline layer is 1.2~1.6 nm.

[0051] Furthermore, the method for forming the buffer layer 6 includes the following steps:

[0052] A buffer layer 6 is deposited on the surface of the electron transport layer 4, wherein the vacuum degree is 18~25 Pa, the deposition temperature is 145~155℃, the water source pressure is 45~55 Pa, the tin source pressure is 20~30 Pa, and the number of cycles is 180~220.

[0053] Furthermore, the method for forming the front composite layer 7 includes the following steps:

[0054] The stacked structure with buffer layer 6 is placed in a mask of composite layer, and the front composite layer 7 is sputtered (e.g., DC magnetron sputtering) on ​​the surface of buffer layer 6. The substrate temperature during sputtering is 58~63°C (e.g., 60°C), and the intracavitary pressure during sputtering is 9.8~10.0×10⁻⁶. -4 Pa (e.g., 9.9 × 10⁻⁴ Pa), argon flow rate of 18–20 sccm, oxygen flow rate of 0.25–0.5 sccm (e.g., 0.3 sccm), sputtering is performed in two stages (including a first sputtering and a second sputtering performed sequentially), the first sputtering intensity is 35–40 W and the sputtering time is 5–7 min (e.g., 6.5 min), the second sputtering intensity is 140–155 W (e.g., 150 W) and the sputtering time is 3.5–5 min (e.g., 4 min).

[0055] Furthermore, the method for forming the positive electrode 5 and the back electrode 8 includes the following steps:

[0056] The stacked structure with the front composite layer 7 is placed in the masks of the positive electrode 5 and the back electrode 8, respectively. The masks are then placed in a vacuum deposition apparatus to fabricate the positive electrode 5 and the back electrode 8, wherein the vacuum degree is 6~7×10 -4 Pa, the thickness of the positive electrode 5 is 385~400nm, and the thickness of the back electrode 8 is 185~200nm.

[0057] Furthermore, the method for forming the antireflection layer 9 includes the following steps:

[0058] A stacked structure with a positive electrode 5 and a back electrode 8 is placed on a photomask, and then the photomask is placed in a vacuum deposition apparatus to prepare the antireflection layer 9, with a vacuum level of 9.9~10.3×10⁻⁶. -4 Pa, with a thickness of 100~105 nm.

[0059] Example 1

[0060] This embodiment provides a method for fabricating a perovskite solar cell based on a template layer, and the fabricated perovskite single-junction cell is as follows: Figure 1 As shown, it includes: a conductive glass substrate 1 and a hole transport layer 2, a perovskite light-absorbing layer 3, an electron transport layer 4, and a positive electrode 5 sequentially stacked on the light-receiving surface of the conductive glass substrate; the perovskite single-junction solar cell is prepared by the following steps:

[0061] Step a: Cut 1.5×1.5cm 2 The ITO conductive glass substrate was ultrasonically cleaned in acetone and anhydrous ethanol for 15 min in sequence. Then, the ITO conductive glass substrate was dried with nitrogen and treated in ozone for 15 min.

[0062] Step b: Place the ITO conductive glass substrate obtained in step a into a mask for sputtering the nickel oxide hole transport layer. Place the mask containing the ITO conductive glass substrate into a magnetron sputtering apparatus and evacuate to a vacuum level of 9.9 × 10⁻⁶. -4 At Pa, select the radio frequency magnetron sputtering mode, adjust the power to 90W, set the argon flow rate to 20sccm, and the sputtering time to 10min;

[0063] Step c: After sputtering, the ITO conductive glass substrate is transferred to a spin coater in a nitrogen glove box and a 2PACz layer is spin-coated. The amount of 2PACz is 50 μL, the spin speed is 3000 rpm, the acceleration is 3000 rpm / s, and the time is 30 s. Then, it is annealed at 100℃ for 10 min on a hot stage to obtain the stacked structure of ITO conductive glass substrate / hole transport layer.

[0064] Step d: Place the stacked structure and mask obtained in step c into a vacuum evaporation apparatus and evacuate to a vacuum level of 9.9 × 10⁻⁶. -4 At Pa, the rate of CsBr was adjusted to 0.12 Å / s, the rate of PbI2 was adjusted to 1.08 Å / s, the total evaporation thickness was 200 nm, and after evaporation, a stacked structure of ITO conductive glass substrate / hole transport layer / PbI2 was obtained.

[0065] Step e: Place the stacked structure from step d in a sealed glove box with a relative humidity of 10-20%. Immerse 5-10 μL of a selected polar solvent molecule with a purity of 99% (DMSO solution, DMF solution, and DMAc solution in a volume ratio of 1:3:1) onto a precisely temperature-controlled heating stage. Steam fumigate at a temperature of 80-150°C to create a constant atmosphere. After processing in this way for 5-20 minutes, a stacked structure of ITO conductive glass substrate / hole transport layer / PbI2 / organic polar solvent gas molecule layer is obtained.

[0066] Step f: Weigh 77.5 mg FAI, 5.7 mg MACl, 12.6 mg MABr, and 9.2 mg FACl and dissolve them in 1 mL of anhydrous ethanol. Shake at room temperature for 30 min to obtain a perovskite precursor solution.

[0067] The stacked structure from step e was placed on a spin coater, and 75 μL of perovskite precursor solution was added for spin coating. The spin coating was performed at a speed of 3000 rpm, an acceleration of 3000 rpm / s, and a time of 30 s, resulting in a stacked structure of ITO conductive glass substrate / hole transport layer / PbI2 / mixed organic polar solvent gas molecule layer / perovskite precursor solution layer.

[0068] Step g: The stacked structure obtained in step f is placed on a hot table with an ambient humidity of 50% and a temperature of 150°C and annealed for 30 minutes to obtain a stacked structure of ITO conductive glass substrate / hole transport layer / perovskite light-absorbing layer, wherein the thickness of the perovskite light-absorbing layer is 350 nm.

[0069] Step h: Place the stacked structure obtained in step g into a mask for the electron transport layer, and place the mask in a vacuum deposition apparatus with a vacuum level of 9.9 × 10⁻⁶. -4 LiF and C are deposited at Pa. 60 With 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), a deposition rate of 0.1 Å / s was obtained, with thicknesses of 1 nm, 10 nm and 1.5 nm, respectively, to obtain a stacked structure of ITO conductive glass substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer;

[0070] Step i: Place the stacked structure obtained in step h in a silver-evaporating mask, and then place the mask in a vacuum deposition apparatus with a vacuum level of 9.9 × 10⁻⁶. -4 Silver electrodes were deposited at Pa at a deposition rate of approximately 2 Å / s, resulting in a perovskite single-junction cell with a deposition thickness of 120 nm.

[0071] Example 2

[0072] This embodiment provides a method for fabricating a perovskite solar cell based on a template layer, and the resulting perovskite-silicon tandem solar cell is as follows: Figure 2 As shown, the perovskite-silicon tandem solar cell includes: a conductive silicon substrate 1, a hole transport layer 2, a perovskite light-absorbing layer 3, an electron transport layer 4, a buffer layer 6, a front composite layer 7, and a positive electrode 5 sequentially stacked on the light-receiving surface of the conductive silicon substrate; an anti-reflection layer 9 disposed on the surface of the front composite layer 7 and located between the two positive electrodes 5; and a back electrode 8 formed on the back surface of the conductive silicon substrate. The perovskite-silicon tandem solar cell is prepared by the following steps:

[0073] Step a: Cut a 15×15cm 2 The silicon-based solar cell was cut into 2×2cm pieces. 2 The silicon wafer has a center area of ​​1.2 × 1.2 cm. 2 The substrate composite layer is controlled to have a cutting accuracy error within 1 mm. The cut silicon wafer is annealed at 200℃ for 15 min to obtain a conductive silicon substrate. The thickness of the conductive silicon substrate is 150 μm, and both p-type and i-type amorphous silicon are 5 nm. The thicknesses of the front substrate composite layer and the back substrate composite layer are 10 nm and 80 nm, respectively.

[0074] Step b: Place the conductive silicon substrate obtained in step a into a mask for sputtering the nickel oxide hole transport layer. Place the mask containing the conductive silicon substrate into a magnetron sputtering apparatus and set the vacuum to 9.9 × 10⁻⁶. -4 At Pa, select the radio frequency magnetron sputtering mode, adjust the power to 90W, set the argon flow rate to 20sccm, and the sputtering time to 10min;

[0075] Step c: After sputtering, the conductive silicon substrate is transferred to a spin coater in a nitrogen glove box and a 2PACz layer is spin coated. The amount of 2PACz is 100 μL, the rotation speed is 3000 rpm, the acceleration is 3000 rpm / s, and the time is 30 s. Then, it is annealed on a hot stage at 100℃ for 10 min to obtain a stacked structure of conductive silicon substrate / hole transport layer.

[0076] Step d: Place the stacked structure and mask obtained in step c into a vacuum evaporation apparatus and evacuate to a vacuum level of 9.9 × 10⁻⁶. -4 At Pa, the rate of CsBr was adjusted to 0.12 Å / s, the rate of PbI2 was adjusted to 1.08 Å / s, the total evaporation thickness was 200 nm, and after evaporation, a stacked structure of ITO conductive glass substrate / hole transport layer / PbI2 was obtained.

[0077] Step e: Place the stacked structure from step d in a sealed glove box with a relative humidity of 10-20%. Immerse 5-10 μL of a selected polar solvent molecule with a purity of 99% (DMSO solution, DMF solution, and DMAc solution in a volume ratio of 1:3:1) onto a precisely temperature-controlled heating stage. Steam fumigate at a temperature of 80-150°C to create a constant atmosphere. After processing in this way for 5-20 minutes, a stacked structure of ITO conductive glass substrate / hole transport layer / PbI2 / mixed organic polar solvent gas molecule layer is obtained.

[0078] Step f: Weigh 77.5 mg FAI, 5.7 mg MACl, 12.6 mg MABr, and 9.2 mg FACl and dissolve them in 1 mL of anhydrous ethanol. Shake at room temperature for 30 min to obtain a perovskite precursor solution.

[0079] The stacked structure from step e was placed on a spin coater, and 100 μL of perovskite precursor solution was added for spin coating. The spin coating was performed at a speed of 4000 rpm, an acceleration of 4000 rpm / s, and a time of 30 s, resulting in a stacked structure of conductive silicon substrate / hole transport layer / PbI2 / mixed organic polar solvent gas molecule layer / perovskite precursor solution layer.

[0080] Step g: The stacked structure obtained in step f is placed on a hot table with an ambient humidity of 70% and a temperature of 170°C and annealed for 30 minutes to obtain a stacked structure of conductive silicon substrate / hole transport layer / perovskite light-absorbing layer, wherein the thickness of the perovskite light-absorbing layer is 400 nm.

[0081] Step h: Place the stacked structure obtained in step g into a mask for the electron transport layer, and place the mask in a vacuum deposition apparatus with a vacuum level of 9.9 × 10⁻⁶. -4 LiF and C are deposited at Pa. 60 With 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), a deposition rate of 0.1 Å / s was obtained, with thicknesses of 1 nm, 10 nm and 1.5 nm, respectively, to obtain a stacked structure of conductive silicon substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer;

[0082] Step i: The stacked structure obtained in step h is placed in the atomic layer deposition chamber to prepare the buffer layer. The vacuum degree is 20 Pa, the chamber temperature is 150 °C, the water source and tin source pressures are 50 Pa and 25 Pa, respectively, and the number of cycles is 200, to obtain the stacked structure of conductive silicon substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer / buffer layer.

[0083] Step j: Place the stacked structure obtained in step i into a mask for the ITO front composite layer, and then place the mask into a magnetron sputtering apparatus to fabricate the ITO layer. The substrate temperature is 60℃ and the cavity pressure is 9.9×10⁻⁶. -4 Pa, argon flow rate of 20 sccm, oxygen flow rate of 0.3 sccm, sputtering mode of DC magnetron sputtering, 40W sputtering for 6.5 min, 150W sputtering for 4 min, to obtain a stacked structure of conductive silicon substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer / buffer layer / front composite layer.

[0084] Step k: Place the stacked structure obtained in step j into the masks for the positive electrode and the back electrode, respectively. Then, place the masks in a vacuum deposition apparatus to fabricate the electrodes at a vacuum level of 7 × 10⁻⁶. -4 Pa, with the thicknesses of the positive electrode and the back electrode being 400 nm and 200 nm respectively, yields a stacked structure of back electrode / conductive silicon substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer / buffer layer / front composite layer / positive electrode.

[0085] Step 1: Place the laminated structure obtained in step k in a 1.1 × 1.1 cm space. 2 On the mask, the mask is then placed in a vacuum deposition apparatus to prepare the antireflection layer, with a vacuum level of 9.9 × 10⁻⁶. -4 Pa, with a thickness of 100 nm, yielded a perovskite-silicon tandem solar cell.

[0086] The beneficial effects of the present invention will be described in detail below with reference to the test results. In order to illustrate the beneficial effects of the present invention more intuitively, the present invention provides Comparative Example 1 and Comparative Example 2.

[0087] Comparative Example 1: The raw materials, steps, and process conditions used in this comparative example are basically the same as those in Example 1. The only difference is that the organic polar solvent gas molecule layer is not prepared in advance during the preparation of the perovskite light-absorbing layer. That is to say, step e and subsequent steps related to the mixed organic polar solvent gas molecule layer are not included.

[0088] Comparative Example 2: The raw materials, steps, and process conditions used in this comparative example are basically the same as those in Example 2. The only difference is that the organic polar solvent gas molecule layer is not prepared in advance during the preparation of the perovskite light-absorbing layer. That is to say, step e and subsequent steps related to the mixed organic polar solvent gas molecule layer are not included.

[0089] The solar cells prepared in Examples 1-2 and Comparative Examples 1-2 were subjected to relevant performance tests, and the results are shown in Table 1. The short-circuit current density (Jsc), open-circuit voltage (Voc), fill factor (FF), and conversion efficiency (PCE) were all measured under standard test conditions (AM1.5, 25℃, 1000W / m²). 2 The result was measured below.

[0090] Table 1 Battery Performance Table

[0091]

[0092] As can be clearly seen from Table 1, the electrical performance parameters of Examples 1-2 are significantly superior to those of Comparative Examples 1-2. Specifically, for the tandem perovskite solar cell, the short-circuit current density is 19.99 mA / cm². 2 The open-circuit voltage is 1.834V, the fill factor is 76.91%, and the conversion efficiency is 28.20%. For a single-junction perovskite solar cell, the short-circuit current density is 21.25 mA / cm². 2 The open-circuit voltage is 1.249 V, the fill factor is 77.85%, and the conversion efficiency is 20.67%.

[0093] like Figure 3 The image shows the XRD patterns of the perovskite light-absorbing layer with a pre-prepared organic polar solvent gas molecule layer in Example 1 and the reference perovskite film in Comparative Example 1. Figure 3 It can be seen that the crystallinity of the perovskite light-absorbing layer in Example 1 is better than that of the reference perovskite film. The reference perovskite film contains residual PbI2, which can trap charge carriers at defect centers, thereby affecting the overall performance of the perovskite solar cell.

[0094] like Figure 4 The images show SEM planar images of the bottom interface of the perovskite films formed in Comparative Example 1 and Example 1, and SEM cross-sectional images of the textured multilayer perovskite films formed in Comparative Example 2 and Example 2. It can be clearly seen that the inorganic framework layer film formed in Comparative Example 1 is a dense and continuous "stacked sheet" structure, while the inorganic framework layer film formed in Example 1 has significantly increased porosity and has been reconstructed from the original sheet structure into a rod-shaped or dot-shaped structure. This indicates that the mixed organic polar solvent gas molecule layer has a destructive effect on the dense film, which is beneficial to promoting the deep penetration of the subsequent perovskite precursor solution. Compared with the cross-section of the perovskite film in Comparative Example 2, Example 2 shows uniform, large-sized grains that can penetrate the entire film, which improves the problems of small and disordered grains, poor crystal quality, and scattered PbI2 residual fragments at the bottom of the film. This indicates that the phenomenon of residual lead iodide has been significantly improved.

[0095] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All disclosed features, or steps in all methods or processes, may be combined in any way except for mutually exclusive features and / or steps.

Claims

1. A method for fabricating a perovskite solar cell based on gas phase assistance, characterized in that, Includes the following steps: Step 1: Use a conductive substrate and form a hole transport layer on the surface of the conductive substrate; Step 2: An inorganic framework layer is deposited on the upper surface of the hole transport layer by vapor deposition; Step 3: An organic polar solvent gas molecule layer is formed on the upper surface of the inorganic framework layer by steam fumigation based on organic polar solvent gas components; Step 4: Form a perovskite precursor solution layer in the organic polar solvent gas molecule layer; formation; Step 5: Perform high-temperature and humidity annealing on the stacked structure consisting of the inorganic framework layer, the organic polar solvent gas molecule layer, and the perovskite precursor solution layer to form a perovskite light-absorbing layer. Step 6: Sequentially form an electron transport layer and a positive electrode on the surface of the perovskite light-absorbing layer to obtain a perovskite single-junction cell; or, sequentially form an electron transport layer, a buffer layer, a front composite layer, a positive electrode, and an anti-reflection layer on the surface of the perovskite light-absorbing layer, and form a back electrode on the back side of the conductive substrate to obtain a perovskite-silicon tandem cell.

2. The method for fabricating a perovskite solar cell based on gas-phase assistance according to claim 1, characterized in that, The thickness ratio of the inorganic framework layer, the organic polar solvent gas molecule layer, and the perovskite precursor solution layer is (200~320):(1~2):(350~550).

3. The method for fabricating a perovskite solar cell based on gas-phase assistance according to claim 1, characterized in that, The formation process of the inorganic framework layer is as follows: Cesium bromide and lead iodide were vapor-deposited on the upper surface of the hole transport layer to form an inorganic framework layer. The evaporation rate of cesium bromide was 0.11–0.12 Å / s, and the evaporation rate of lead iodide was 1.08–1.09 Å / s. The vacuum degree for both was 9.5–9.9 × 10⁻⁶. -4 Pa.

4. The method for fabricating a perovskite solar cell based on gas-phase assistance according to claim 1, characterized in that, The formation process of organic polar solvent gas molecular layers is as follows: In a sealed glove box with a relative humidity of 10-20%, 5-10 μL of organic polar solvent with a purity greater than 99% is placed on a heating stage and steamed at a temperature of 80-150°C to form a constant atmosphere. After steam fumigation for 5-20 minutes, an organic polar solvent gas molecule layer is formed on the upper surface of the inorganic framework layer.

5. The method for fabricating a perovskite solar cell based on gas-phase assistance according to claim 4, characterized in that, The organic polar solvent is one or more of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP).

6. The method for fabricating a perovskite solar cell based on gas phase assistance according to claim 1, characterized in that, The formation process of the perovskite precursor solution layer is as follows: Prepare a perovskite precursor solution, including: methylammonium bromide (MABr), methylammonium chloride (MACl), formamidinium chloride (FACl), and formamidinium iodide (FAI) and an organic solvent; set the spin coating speed to 3000~4000 rpm, the spin coating acceleration to 3000~4000 rpm / s, and the spin coating time to 25~30s.

7. The method for fabricating a perovskite solar cell based on gas phase assistance according to claim 6, characterized in that, In the perovskite precursor solution, the mass ratio of formamidinium iodide, methylammonium chloride, methylammonium bromide, and formamidinium chloride is 75~80:5.5~6.0:12~13:8~11.

8. The method for fabricating a perovskite solar cell based on gas-phase assistance according to claim 1, characterized in that, The specific process of high-temperature and humidity annealing is as follows: Set the high-temperature humidity annealing temperature to 150~170℃, the humidity to 50~75%, and the time to 25~30min.

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