Perovskite solar cell and method of manufacturing the same

Abstract

This invention relates to the field of perovskite solar cell technology, and discloses a perovskite solar cell and its fabrication method. The fabrication method includes: forming a perovskite layer; coating the surface of the perovskite layer with a passivation liquid to obtain a passivation liquid film, wherein the passivation liquid contains a guanidinocarboxylic acid compound and tetrasodium diacetate; annealing the passivation liquid film to form a passivation layer; and forming an inorganic electron transport layer on the side of the passivation layer opposite to the perovskite layer, wherein the inorganic electron transport layer is made of a metal oxide. This passivation layer not only reduces the defect density on the surface of the perovskite layer and suppresses nonradiative recombination, but also acts as a bridge between the inorganic electron transport layer and the perovskite layer, improving the electron extraction rate, thereby improving the photoelectric conversion efficiency and stability of the cell.

Description

Technical Field

[0001] This invention relates to the field of perovskite solar cell technology, specifically to perovskite solar cells and their fabrication methods. Background Technology

[0002] In recent years, the global ecological environment has deteriorated and energy shortages have become increasingly severe. Solar energy, with its abundant reserves, wide distribution, renewable nature, and pollution-free characteristics, is considered key to solving energy shortages and environmental pollution problems. Solar cells, as an effective way to utilize solar energy, work by directly converting solar radiation into electrical energy using the photovoltaic effect. Perovskite solar cells, as the third generation of solar cells, have become a highly promising emerging research direction in the field of solar cells due to their advantages such as low cost, simple fabrication process, and high photoelectric conversion efficiency. In just over a decade, the efficiency of single-junction perovskite solar cells has increased from 3.8% to over 26.7%, demonstrating enormous development potential. This significant progress is mainly attributed to the unique photoelectric properties of the perovskite material in the perovskite layer of perovskite solar cells, such as direct bandgap, wide light absorption range, low exciton binding energy, long carrier diffusion length, and good carrier stability. However, defects exist at the interface of the perovskite layer. The presence of interface defects not only causes severe interfacial recombination loss, thereby reducing the photoelectric conversion performance of perovskite solar cells, but also affects the stability of perovskite solar cells, becoming a key factor limiting their efficiency improvement and long-term stability. Summary of the Invention

[0003] In view of this, the present invention provides a perovskite solar cell and a method for preparing the same, so as to improve the photoelectric conversion efficiency and stability of perovskite solar cells.

[0004] In a first aspect, the present invention provides a method for preparing a perovskite solar cell, comprising: forming a perovskite layer; coating the surface of the perovskite layer with a passivation liquid to obtain a passivation liquid film, wherein the passivation liquid contains a guanidine carboxylic acid compound and tetrasodium diacetate of glutamic acid; annealing the passivation liquid film to form a passivation layer; and forming an inorganic electron transport layer on the side of the passivation layer opposite to the perovskite layer, wherein the material of the inorganic electron transport layer is a metal oxide.

[0005] In guanidinocarboxylic acid compounds, the guanidino group (-NH-C(=NH)-NH2) can form coordination bonds with uncoordinated metal cations on the perovskite layer surface to passivate metal vacancy defects, and also with metal elements on the inorganic electron transport layer surface. Similarly, tetrasodium glutamate diacetate can form coordination bonds with both uncoordinated metal cations and metal elements on the inorganic electron transport layer surface. Therefore, this passivation layer not only reduces the defect density on the perovskite layer surface and suppresses nonradiative recombination, but also acts as a bridge between the inorganic electron transport layer and the perovskite layer, increasing the electron extraction rate, thereby improving the open-circuit voltage, fill factor, and even photoelectric conversion efficiency of the battery. The reduction in defect density on the perovskite layer surface also contributes to improved battery stability. Furthermore, the amino group in the guanidino group can form a hydrogen bond network with halide ions on the perovskite layer surface, inhibiting halide ion migration and further enhancing battery stability.

[0006] In some alternative embodiments, the guanidinocarboxylic acid compounds include one or more of guanidinoacetic acid, β-guanidinopropionic acid, guanidinobutyric acid, and guanidinovalerate.

[0007] In some alternative embodiments, the material of the inorganic electron transport layer includes at least one of SnO2 and TiO2.

[0008] In some optional embodiments, the solvent of the passivation solution is at least one of isopropanol and ethanol.

[0009] In some optional embodiments, the mass concentration ratio of the guanidinocarboxylic acid compound and the tetrasodium diacetate of glutamate in the passivation solution is (0.5-1.4):1, preferably (0.8-1.2):1.

[0010] In some optional embodiments, the concentration of the guanidinocarboxylic acid compound in the passivation solution is 0.018 mg / ml to 0.05 mg / ml; and / or, the concentration of tetrasodium diacetate of glutamate in the passivation solution is 0.013 mg / ml to 0.1 mg / ml.

[0011] In some alternative embodiments, the passivation solution is coated onto the surface of the perovskite layer using a slot coating process.

[0012] In some alternative embodiments, during the application of the passivation solution, the distance between the blade lip and the perovskite layer is 80 μm-150 μm.

[0013] In some alternative embodiments, the coating speed during the application of the passivation solution is 15 mm / s to 30 mm / s.

[0014] In some alternative embodiments, the pressure is 0.1 MPa-1 MPa during the application of the passivation solution.

[0015] In some alternative embodiments, the injection rate during the application of the passivation solution is 10 μL / s to 25 μL / s.

[0016] In some alternative embodiments, the annealing temperature is 90°C-120°C and the annealing time is 8 min-12 min.

[0017] In some alternative embodiments, the annealing is performed in a nitrogen atmosphere or an inert gas atmosphere.

[0018] In a second aspect, the present invention provides a perovskite solar cell, comprising a substrate, a perovskite layer, a passivation layer, and an inorganic electron transport layer; the perovskite layer is located on one side of the substrate; the passivation layer is located on the side surface of the perovskite layer opposite to the substrate, and the passivation layer contains a guanidine carboxylic acid compound and tetrasodium diacetate of glutamic acid; the inorganic electron transport layer is located on the side surface of the passivation layer opposite to the perovskite layer.

[0019] In some alternative implementations, the thickness of the passivation layer is 1 nm to 2 nm.

[0020] In some alternative embodiments, the perovskite solar cell is a tandem perovskite solar cell or a single-junction perovskite solar cell. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of the present invention, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a perovskite solar cell according to an embodiment of the present invention.

[0023] Figure 2 These are the PCE variation curves of the tandem perovskite solar cells of Example 1 and Comparative Example 1. Figure 3 These are the JV curves of the tandem perovskite solar cells of Examples 1-7 and Comparative Examples 1-3.

[0024] Explanation of reference numerals in the attached figures: 1-Substrate; 2-Hole transport layer; 3-Perovskite layer; 4-Passivation layer; 5-Inorganic electron transport layer; 6-Second electrode layer. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings, not all structures. Where specific experimental steps or conditions are not specified in the embodiments, they can be performed according to the conventional experimental steps or conditions described in the literature in the art. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0026] In a first aspect, the present invention provides a method for preparing a perovskite solar cell, comprising: forming a perovskite layer; coating the surface of the perovskite layer with a passivation liquid to obtain a passivation liquid film, wherein the passivation liquid contains a guanidinocarboxylic acid compound and tetrasodium diacetate of glutamic acid; annealing the passivation liquid film to remove the solvent in the passivation liquid film to form a passivation layer; and forming an inorganic electron transport layer on the side of the passivation layer opposite to the perovskite layer, wherein the material of the inorganic electron transport layer is a metal oxide.

[0027] In guanidinocarboxylic acid compounds, the guanidino group (-NH-C(=NH)-NH2) can form coordinate bonds with uncoordinated metal cations on the perovskite layer surface to passivate metal vacancy defects, and also with metal elements on the inorganic electron transport layer surface. Similarly, tetrasodium glutamate diacetate, an anionic ligand, can form coordinate bonds with both uncoordinated metal cations and metal elements on the inorganic electron transport layer surface. Therefore, this passivation layer not only reduces the defect density on the perovskite layer surface and suppresses nonradiative recombination, but also acts as a bridge between the inorganic electron transport layer and the perovskite layer, increasing the electron extraction rate, thereby improving the open-circuit voltage, fill factor, and even photoelectric conversion efficiency of the battery. The reduction in defect density on the perovskite layer surface also contributes to improved battery stability. Furthermore, the amino group in the guanidino group can form a hydrogen bond network with halide ions on the perovskite layer surface, inhibiting halide ion migration and further enhancing battery stability.

[0028] The following is combined with Figure 1 A clear and complete description of the fabrication method for perovskite solar cells is provided: Step S1: Provide substrate 1.

[0029] The substrate 1 can be a conductive substrate or a battery cell.

[0030] When the substrate 1 is a conductive substrate, the perovskite solar cell is a single-junction cell. The conductive substrate includes an insulating substrate (not shown) and a first electrode layer (not shown) located on one side surface of the insulating substrate. The insulating substrate includes, but is not limited to, glass and flexible polymer substrates. The flexible polymer substrate includes, but is not limited to, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). The material of the first electrode layer is a transparent conductive oxide, such as fluorinated tin oxide (FTO), indium tin oxide (ITO), or aluminum-doped zinc oxide (AZO). For example, the conductive substrate can be commercially available FTO conductive glass, ITO conductive glass, ITO / PET flexible substrate, or ITO / PEN flexible substrate.

[0031] When the substrate 1 is the bottom cell, the perovskite solar cell is a tandem cell. The bottom cell includes, but is not limited to, copper indium gallium selenide (CIGS) cells and crystalline silicon cells. Crystalline silicon cells include, but are not limited to, emitter and back passivation (PERC) cells, tunnel oxide passivated contact (TOPCon) cells, and heterojunction (HJT) cells. One side surface of the bottom cell has a transparent conductive oxide layer as a tunneling layer (not shown).

[0032] Step S2: Form a hole transport layer 2 on one side surface of the substrate 1.

[0033] Specifically, the hole transport layer 2 is formed on the surface of the first electrode layer or tunneling layer. The substrate 1 can be ozone treated before forming the hole transport layer 2 to remove residual organic matter from the surface of the first electrode layer or tunneling layer.

[0034] The materials of hole transport layer 2 include, but are not limited to, nickel oxide (NiO). x The hole transport layer 2 can be formed from one or more of the following: cuprous oxide, cuprous thiocyanate, triphenylmethane and its derivatives, butadiene-based hole transport materials, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), polytriarylamine (PTAA), MeO-2PACz, Me-4PACz, and 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD). The process for forming the hole transport layer 2 includes, but is not limited to, spin coating, blade coating, spray coating, vapor deposition, and magnetron sputtering. Vapor deposition processes include chemical vapor deposition or physical vapor deposition (such as vacuum evaporation). The specific process can be selected based on the material of the hole transport layer 2.

[0035] The thickness of the hole transport layer 2 can be 20nm-30nm.

[0036] Step S3: Form a perovskite layer 3 on the side of the hole transport layer 2 facing away from the substrate 1.

[0037] In some alternative embodiments, the step of forming the perovskite layer 3 may include: Step S31: Deposit an inorganic salt layer on the surface of hole transport layer 2 using a vacuum evaporation process.

[0038] The inorganic salt layer is made of BX, where B is at least one of lead and cesium, and X is at least one of iodine, bromine, and chlorine. The deposition rate of any inorganic salt is 0.2 Å / s–5.2 Å / s. For example, the deposition rates are ordered as follows: cesium iodide < lead bromide < lead iodide, with a deposition rate of 0.1 Å / s–0.3 Å / s for cesium iodide, 0.3 Å / s–0.5 Å / s for lead bromide, and 4.5 Å / s–5.2 Å / s for lead iodide. The deposition rates of different inorganic salts directly affect the content of different metal elements in the perovskite layer 3.

[0039] Step S32: Coat the surface of the inorganic salt layer with an organic amine salt solution.

[0040] Specifically, the solute in the organic ammonium salt solution is AX, where A includes, but is not limited to, at least one of methylamine ions and formamidinium ions, and X is at least one of iodine, bromine, and chlorine. The solvent for the organic ammonium salt solution can be isopropanol or ethanol. As an example, the concentrations of each solute in the organic ammonium salt solution can be as follows: formamidinium iodide (FAI) concentration is 38 mg / ml to 45 mg / ml, methylammonium iodide (MAI) concentration is 9 mg / ml to 12 mg / ml, formamidinium bromide (FABr) concentration is 17 mg / ml to 23 mg / ml, and methylammonium chloride (MACl) concentration is 6 mg / ml to 8 mg / ml. The coating process for organic amine salt solutions includes, but is not limited to, spray coating, slot coating, spin coating, and blade coating, with slot coating being the preferred method. Slot coating is suitable for the fabrication of large-area perovskite solar cells. The coating of organic amine salt solutions can be performed under an inert gas atmosphere or a nitrogen atmosphere. Alternatively, organic amine salts can be deposited using a vacuum evaporation process.

[0041] Step S33: Annealing is performed to obtain perovskite layer 3.

[0042] Annealing can be carried out in an inert gas atmosphere or a nitrogen atmosphere, or in an environment with humidity below or equal to 18% and oxygen content below or equal to 18%. The annealing temperature is 120℃~150℃, and the annealing time is 5min~15min.

[0043] In other alternative implementations, the perovskite layer 3 can be deposited using a one-step solution method, a two-step solution method, or a one-step vacuum evaporation process.

[0044] The perovskite layer 3 can be made of three-dimensional perovskite, with the general structural formula ABX3. The thickness of the perovskite layer 3 can be 400nm-700nm, such as 400nm, 450nm, 470nm, 500nm, 520nm, 550nm, 570nm, 580nm, 600nm, etc.; preferably 450nm-500nm.

[0045] Step S4: A passivation liquid is coated on the surface of the perovskite layer 3 to obtain a passivation liquid film. The passivation liquid contains guanidine carboxylic acid compounds and tetrasodium diacetate of glutamic acid.

[0046] The guanidinocarboxylic acid compounds include, but are not limited to, one or more of guanidinoacetic acid, β-guanidinopropionic acid, guanidinobutyric acid, and guanidinovalerate. The solvent for the passivation solution can be at least one of isopropanol and ethanol.

[0047] The mass ratio of the guanidinocarboxylic acid compound and the tetrasodium diacetate of glutamic acid in the passivation solution can be (0.5-1.4):1, such as 0.6:1, 0.8:1, 1:1, 1.2:1, etc., preferably (0.8-1.2):1.

[0048] Specifically, the concentration of the guanidinocarboxylic acid compound in the passivation solution can be 0.018 mg / ml-0.05 mg / ml, such as 0.02 mg / ml, 0.025 mg / ml, 0.03 mg / ml, 0.035 mg / ml, 0.04 mg / ml, 0.045 mg / ml, etc.; the concentration of the tetrasodium diacetate of glutamic acid in the passivation solution can be 0.013 mg / ml-0.1 mg / ml, such as 0.02 mg / ml, 0.04 mg / ml, 0.06 mg / ml, 0.08 mg / ml, etc.

[0049] Passivation solution can be applied using spin coating, scraping coating, spraying, or slot coating processes.

[0050] In some optional embodiments, the passivation liquid is coated onto the surface of the perovskite layer 3 using a slot coating process. This slot coating process is suitable for the fabrication of large-area perovskite solar cells. Specifically, the passivation liquid is pumped into the slot die by a feed pump and uniformly extruded from the narrow slot of the die under pressure, forming a stable liquid meniscus between the die lip and the perovskite layer 3. The substrate 1 moves along a certain direction, spreading the passivation liquid onto the surface of the perovskite layer 3, ultimately forming a uniformly thick wet film.

[0051] During the slit coating process, the distance between the blade lip and the perovskite layer 3 can be 80μm-150μm, such as 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, etc. The coating speed can be 15mm / s-30mm / s, such as 15mm / s, 20mm / s, 25mm / s, 30mm / s, etc. The pressure can be 0.1MPa-1MPa, such as 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa, 1MPa, etc. The injection rate can be 10μL / s-25μL / s, such as 10μL / s, 15μL / s, 20μL / s, 25μL / s, etc.

[0052] Step S5: Anneal the passivation liquid film to remove the solvent in the passivation liquid film and form a passivation layer 4; The annealing temperature is 90℃-120℃, such as 90℃, 100℃, 110℃, 120℃, etc.; the annealing time is 8min-12min, such as 8min, 10min, 12min, etc. The annealing is carried out in a nitrogen atmosphere or an inert gas atmosphere.

[0053] The thickness of the passivation layer 4 can be 1nm-2nm.

[0054] Step S6: An inorganic electron transport layer 5 is formed on the side of the passivation layer 4 facing away from the perovskite layer 3. The material of the inorganic electron transport layer 5 is a metal oxide.

[0055] The inorganic electron transport layer 5 can be formed using processes such as magnetron sputtering and atomic layer deposition. The material of the inorganic electron transport layer 5 includes at least one of SnO2 and TiO2. The thickness of the inorganic electron transport layer 5 can be 15nm-30nm.

[0056] Step S7: A second electrode layer 6 is formed on the side of the inorganic electron transport layer 5 facing away from the perovskite layer 3.

[0057] The second electrode layer 6 may include a transparent conductive oxide layer and metal gate lines, wherein the metal gate lines are located on the side of the transparent conductive oxide layer facing away from the inorganic electron transport layer 5. The transparent conductive oxide layer may be formed by magnetron sputtering, and the metal gate lines may be formed by vacuum evaporation or screen printing.

[0058] The thickness of the transparent conductive oxide layer can be 55nm-65nm; the thickness of the metal gate line can be 5μm-15μm.

[0059] Secondly, refer to Figure 1This invention provides a perovskite solar cell, comprising a substrate 1, a perovskite layer 3, a passivation layer 4, and an inorganic electron transport layer 5; the perovskite layer 3 is located on one side of the substrate 1; the passivation layer 4 is located on the side surface of the perovskite layer 3 opposite to the substrate 1, and the passivation layer 4 contains a guanidine carboxylic acid compound and tetrasodium diacetate of glutamic acid; the inorganic electron transport layer 5 is located on the side surface of the passivation layer 4 opposite to the perovskite layer 3.

[0060] Specifically, the complete structure of a perovskite solar cell can be a substrate 1, a hole transport layer 2, a perovskite layer 3, a passivation layer 4, an inorganic electron transport layer 5, and a second electrode layer 6 stacked sequentially.

[0061] It should be noted that the characteristics (such as materials, thickness, etc.) and effects described in the first aspect of the perovskite solar cell also apply to the fabrication method of this perovskite solar cell, and will not be repeated here.

[0062] The mass ratio of guanidinocarboxylic acid compounds and tetrasodium glutamate diacetate in passivation layer 4 is determined by the ratio of guanidinocarboxylic acid compounds and tetrasodium glutamate diacetate in the passivation solution; the thickness of passivation layer 4 is determined by the concentration of the passivation solution.

[0063] The perovskite solar cell can be a tandem perovskite solar cell or a single-junction perovskite solar cell. The tandem perovskite solar cell comprises a bottom cell and a top perovskite cell connected in series, with the bottom cell and top perovskite cell connected by a tunneling layer.

[0064] The embodiments of the technical solution of this application are described in detail below. These embodiments are only used to illustrate the technical solution of this application more clearly, and are therefore merely examples and should not be used to limit the scope of protection of this application.

[0065] Example 1 This embodiment provides a method for fabricating a tandem perovskite solar cell, including the following steps: A heterojunction solar cell with dimensions of 166 mm × 166 nm is provided, wherein the N-side of the heterojunction solar cell has an IZO layer with a thickness of 20 nm as a tunneling layer. NiO with a thickness of 20 nm was deposited on the surface of the tunneling layer using magnetron sputtering. x Layer; using slot coating process on NiO x The surface of the layer was coated with a 0.5 mg / ml Me-4PACz solution (methanol as solvent) and annealed at 100 °C for 10 min; NiO x The Me-4PACz layer and the Me-4PACz layer together constitute the hole transport layer; An inorganic salt layer was deposited on the surface of the hole transport layer using a vacuum evaporation process. Specifically, lead iodide, cesium iodide, and lead bromide were placed in three separate evaporation boats. The deposition rate of lead iodide was 5 Å / s, that of lead bromide was 0.5 Å / s, and that of cesium iodide was 0.2 Å / s. The thickness of the inorganic salt layer was 450 nm. An organic amine salt solution was prepared, containing 40 mg / ml FAI, 12 mg / ml MAI, 20 mg / ml FABr, and 8 mg / ml MACl, with isopropanol as the solvent. The organic amine salt solution was placed in a injection pump and coated onto the surface of the inorganic salt layer using a slit coating method. After coating, the layer was annealed at 150 °C for 10 min in an air atmosphere with 18% humidity and 18% oxygen content to obtain a perovskite layer. A passivation solution was prepared, containing 1.96 mg of tetrasodium diacetate and 1.96 mg of β-guanidinopropionic acid in 50 ml of solution, with isopropanol as the solvent. The passivation solution was placed in a dispensing pump and coated onto the surface of the perovskite layer using a slit coating method. During the coating process, the distance between the cutter lip and the perovskite layer was 100 μm, the coating speed was 20 mm / s, the pressure was 0.5 MPa, and the dispensing rate was 15 μL / s. After coating, the perovskite layer was annealed at 100 °C for 10 min in a glove box under a nitrogen atmosphere to obtain the passivation layer. A 20 nm thick SnO2 layer was deposited on the surface of the passivation layer using atomic layer deposition (ALD) as an electron transport layer. A 61 nm thick IZO layer was formed on the surface of the electron transport layer using magnetron sputtering, and a 10 μm thick silver gate was deposited on the IZO surface using vacuum evaporation.

[0066] Example 2 This embodiment provides a method for preparing a tandem perovskite solar cell, which differs from Example 1 only in that the mass of β-guanidinopropionic acid in 50 ml of passivation solution is 0.98 mg.

[0067] Example 3 This embodiment provides a method for preparing a tandem perovskite solar cell, which differs from Example 1 only in that the mass of β-guanidinopropionic acid in 50 ml of passivation solution is 2.35 mg.

[0068] Example 4 This embodiment provides a method for preparing a tandem perovskite solar cell, which differs from Example 1 only in that the mass of β-guanidinopropionic acid in 50 ml of passivation solution is 0.9 mg and the mass of tetrasodium diacetate of glutamic acid is 0.65 mg.

[0069] Example 5 This embodiment provides a method for preparing a tandem perovskite solar cell, which differs from Example 1 only in that the mass of β-guanidinopropionic acid in 50 ml of passivation solution is 2.5 mg and the mass of tetrasodium diacetate of glutamic acid is 5 mg.

[0070] Example 6 This embodiment provides a method for preparing a tandem perovskite solar cell, which differs from Example 1 only in that β-guanidinopropionic acid is replaced with an equal amount of guanidinoacetic acid, while the rest remains unchanged.

[0071] Example 7 This embodiment provides a method for preparing a tandem perovskite solar cell, which differs from Example 1 only in that β-guanidinopropionic acid is replaced with an equal amount of guanidinobutyric acid, while the rest remains unchanged.

[0072] Comparative Example 1 This comparative example provides a method for fabricating a tandem perovskite solar cell, which differs from Example 1 only in that: no passivation layer is formed, and an electron transport layer is deposited on the surface of the perovskite layer.

[0073] Comparative Example 2 This comparative example provides a method for preparing a tandem perovskite solar cell, which differs from Example 1 only in that the solute in the 50ml passivation solution contains only 1.96mg of tetrasodium diacetate of glutamate.

[0074] Comparative Example 3 This comparative example provides a method for preparing a tandem perovskite solar cell, which differs from Example 1 only in that the solute in the 50 ml passivation solution contains only 1.96 mg of β-guanidinopropionic acid.

[0075] Performance testing (1) Photoelectric conversion efficiency test: 100 mW / cm² was provided for perovskite solar cells using an AM 1.5G solar simulator. 2 Under illumination, the current-voltage characteristic curves of the perovskite solar cell were measured using a digital source meter. The open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and power conversion efficiency (PCE) of the perovskite solar cell were obtained. The effective area of ​​the perovskite solar cell was 1 cm². 2 .

[0076] (2) Stability test: The perovskite solar cell was placed in a nitrogen atmosphere at 85℃±5℃, and a pressure of 100mW / cm was applied to the perovskite solar cell. 2Under continuous illumination, the photoelectric conversion efficiency was tested and recorded at different times. The photoelectric conversion efficiency of the perovskite solar cell after 0 hours of exposure to this environment was denoted as PCE0, and the photoelectric conversion efficiency after 1000 hours was denoted as PCE1. The ratio of PCE1 to PCE0 is the PCE retention rate of the perovskite solar cell.

[0077] The performance of the tandem perovskite solar cells of Examples 1-7 and Comparative Examples 1-3 was tested, and the test results are shown in Table 1. Figure 3 The JV curves of the tandem perovskite solar cells of Examples 1-7 and Comparative Examples 1-3 are shown.

[0078] Table 1

[0079] As shown in Table 1, the devices prepared using a mixed passivation solution of guanidinocarboxylic acid compounds and tetrasodium diacetate of glutamic acid exhibit significantly higher open-circuit voltage (Voc), fill factor (FF), and power conversion efficiency (PCE) than the comparative examples. The average Voc of the examples reached 1.85V, an increase of approximately 0.08V compared to the average Voc of 1.77V in the comparative examples; the average FF of the examples was 71.73%, an increase of approximately 3 percentage points compared to the average FF of 68.71% in the comparative examples; the average PCE of the examples reached 26.27%, an increase of approximately 1.64 percentage points compared to the average PCE of 24.63% in the comparative examples; furthermore, the examples showed a higher PCE retention rate compared to the comparative examples. Figure 2 The changes in PCE of the cells in Example 1 and Comparative Example 1 are shown. It is evident that using a mixed passivation solution of guanidinocarboxylic acid compounds and tetrasodium glutamate diacetate can effectively improve the photoelectric conversion performance and stability of perovskite solar cells.

[0080] The above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described above, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of protection of the present invention is determined by the scope of the appended claims.

[0081] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment or implementation of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. The term "implementation" as used herein has a similar understanding. Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0082] In this application, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" represents a group consisting of A, B, and "a combination of A and B". "Containing A and / or B" can mean "containing A, containing B, and containing A and B", or "containing A, containing B, or containing A and B", and can be appropriately understood according to the context.

[0083] In this application, the terms "multiple", "various", "several", "several", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0084] In this application, terms such as "preferred" and "better" merely describe implementation methods or embodiments with better effects and should be understood not to limit the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "preferred" term shall be independent.

[0085] In this application, "optionally" or "optionally" means that something is optional, that is, it is selected from either "with" or "without". If there are multiple "options" in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "option" is independent.

[0086] In this application, open-ended technical features or solutions described using terms such as "contains," "includes," or "comprises" do not exclude additional members beyond those listed unless otherwise specified. Such features or solutions can be considered as providing both closed-ended features or solutions composed of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, if A includes a1, a2, and a3, it may also include other members or exclude additional members unless otherwise specified. This can be considered as providing both features or solutions where "A consists of a1, a2, and a3" or "A is selected from a1, a2, and a3," and features or solutions where "A includes not only a1, a2, and a3, but also other members."

[0087] Furthermore, in this application, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," etc., serve only a non-exhaustive enumeration purpose and should be understood not to constitute a closed limitation on quantity.

Claims

1. A method for preparing a perovskite solar cell, characterized in that, include: Formation of a perovskite layer; A passivation liquid film is obtained by coating the surface of the perovskite layer with a passivation liquid, wherein the passivation liquid contains guanidine carboxylic acid compounds and tetrasodium diacetate of glutamate; The passivation liquid film is annealed to form a passivation layer; An inorganic electron transport layer is formed on the side of the passivation layer opposite to the perovskite layer, and the material of the inorganic electron transport layer is a metal oxide.

2. The preparation method according to claim 1, characterized in that, The guanidinocarboxylic acid compounds include one or more of guanidinoacetic acid, β-guanidinopropionic acid, guanidinobutyric acid, and guanidinovalerate. And / or, the material of the inorganic electron transport layer includes at least one of SnO2 and TiO2; And / or, the solvent of the passivation solution is at least one of isopropanol and ethanol.

3. The preparation method according to claim 2, characterized in that, The mass ratio of the guanidinocarboxylic acid compound and the tetrasodium diacetate of glutamic acid in the passivation solution is (0.5-1.4):1, preferably (0.8-1.2):

1.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The concentration of the guanidinocarboxylic acid compound in the passivation solution is 0.018 mg / ml to 0.05 mg / ml; and / or, the concentration of tetrasodium diacetate of glutamate in the passivation solution is 0.013 mg / ml to 0.1 mg / ml.

5. The preparation method according to claim 1, characterized in that, The passivation solution is coated onto the surface of the perovskite layer using a slot coating process.

6. The preparation method according to claim 5, characterized in that, During the application of the passivation solution, one or more of the following conditions are met: The distance between the blade tip lip and the perovskite layer is 80μm-150μm; The coating speed is 15mm / s-30mm / s; The pressure is 0.1 MPa - 1 MPa; The injection rate is 10 μL / s-25 μL / s.

7. The preparation method according to claim 1, characterized in that, The annealing temperature is 90℃-120℃, and the annealing time is 8min-12min; and / or, the annealing is carried out in a nitrogen atmosphere or an inert gas atmosphere.

8. A perovskite solar cell, characterized in that, include: Base; A perovskite layer, wherein the perovskite layer is located on one side of the substrate; A passivation layer is located on the surface of the perovskite layer facing away from the substrate, and the passivation layer contains a guanidine carboxylic acid compound and tetrasodium diglutamate. An inorganic electron transport layer is located on the surface of the passivation layer opposite to the perovskite layer.

9. The perovskite solar cell according to claim 8, characterized in that, The thickness of the passivation layer is 1nm-2nm.

10. The perovskite solar cell according to claim 8, characterized in that, The perovskite solar cell is a tandem perovskite solar cell or a single-junction perovskite solar cell.

Images