Perovskite solar cell and method of manufacturing the same

Abstract

The application provides a perovskite solar cell, comprising a transparent conductive glass substrate, a hole transport layer, a perovskite light absorption layer, an electron transport layer and an electrode, wherein the hole transport layer is a nickel oxide hole transport layer, and on the surface of the hole transport layer in contact with the perovskite light absorption layer, the ratio of elemental nickel to trivalent nickel is 85:15-99:1, optionally 90:10-99:1, and further optionally 95:5-99:1. The application also provides a method for preparing a perovskite solar cell.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to a perovskite solar cell and its fabrication method. Background Technology

[0002] With the rapid development of the new energy field, solar cells have been widely used in military, aerospace, industrial, commercial, agricultural, and communications fields. Perovskite solar cells, with their advantages of high photoelectric conversion efficiency, simple manufacturing process, and low production and material costs, have gradually become a hot topic in next-generation solar cell research.

[0003] Nickel oxide, as the most commonly used inorganic hole transport layer material in inverted perovskite solar cells, is a preferred candidate for the industrialization of perovskite solar cells. However, the trivalent nickel on the surface of the nickel oxide hole transport layer reacts with A-site cations in the perovskite precursor solution, thereby degrading the photoelectric conversion efficiency of perovskite solar cells. Simultaneously, the erosion of the perovskite light-absorbing layer by water and oxygen can affect the stability of perovskite solar cells to some extent. Therefore, the performance of existing perovskite solar cells still needs improvement. Summary of the Invention

[0004] This application is made in view of the above-mentioned issues, and its purpose is to provide a perovskite solar cell with high photoelectric conversion efficiency and good long-term stability, and whose preparation method is lower in cost and higher in efficiency.

[0005] To achieve the above objectives, this application provides a perovskite solar cell and a method for its fabrication.

[0006] The first aspect of this application provides a perovskite solar cell, comprising a transparent conductive glass substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and an electrode. The hole transport layer is a nickel oxide hole transport layer, wherein elemental nickel is present on the surface of the hole transport layer in contact with the perovskite light-absorbing layer, and the ratio of elemental nickel to trivalent nickel on the surface of the hole transport layer in contact with the perovskite light-absorbing layer is 85:15-99:1, optionally 90:10-99:1, and further optionally 95:5-99:1.

[0007] Therefore, by introducing elemental nickel into the surface where the nickel oxide hole transport layer contacts the perovskite light-absorbing layer, this application reduces the reaction between the high-valence nickel in the nickel oxide hole transport layer and the A-site cations in the perovskite light-absorbing layer, thereby improving the turn-on voltage of the perovskite solar cell and thus improving the photoelectric conversion efficiency of the perovskite solar cell; at the same time, it can further suppress the influence of water and oxygen on the perovskite light-absorbing material, thereby improving the long-term stability of the perovskite solar cell.

[0008] In any embodiment, there is no interface passivation material on the surface of the hole transport layer that contacts the perovskite light-absorbing layer, and optionally there is no p-type interface passivation material.

[0009] In any embodiment, the perovskite solar cell is an inverted perovskite solar cell.

[0010] A second aspect of this application also provides a method for preparing a perovskite solar cell, comprising the following steps:

[0011] Step 1: Provide a transparent conductive glass substrate;

[0012] Step 2: Prepare a hole transport layer on the transparent conductive glass substrate;

[0013] Step 3: Place the transparent conductive glass substrate with the hole transport layer prepared thereon in a sealed device, and introduce carrier gas and reducing gas to react;

[0014] Step 4: Prepare a perovskite light-absorbing layer on the hole transport layer processed in Step 3;

[0015] Step 5: Prepare an electron transport layer on the perovskite light-absorbing layer;

[0016] Step 6: Fabricate electrodes on the electron transport layer to obtain a perovskite solar cell.

[0017] The perovskite solar cell comprises a transparent conductive glass substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and electrodes. The hole transport layer is a nickel oxide hole transport layer. Elemental nickel is present on the surface of the hole transport layer in contact with the perovskite light-absorbing layer. On the surface of the hole transport layer in contact with the perovskite light-absorbing layer, the ratio of elemental nickel to trivalent nickel is 85:15-99:1, optionally 90:10-99:1, and further optionally 95:5-99:1.

[0018] Therefore, the preparation method described in this application uses a reducing gas to treat the surface of the nickel oxide hole transport layer, reducing the surface-charged nickel oxide to nano-sized elemental nickel particles. This helps prevent the decomposition of perovskite caused by the reaction of trivalent nickel with perovskite, thereby improving the photoelectric conversion efficiency and stability of the solar cell.

[0019] In any embodiment, in step 3, the reducing gas is selected from at least one of hydrogen, carbon monoxide, hydrogen sulfide, sulfur dioxide, hydrogen iodide, and ammonia.

[0020] In any embodiment, in step 3, the carrier gas is selected from at least one of nitrogen and argon.

[0021] In any embodiment, in step 3, the ratio of the carrier gas to the reducing gas is 99:1 to 70:30.

[0022] In any embodiment, the reaction time in step 3 is 10-60 minutes.

[0023] In any embodiment, in step 3, the reaction temperature is 150°C-250°C. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the nickel oxide hole transport layer of a perovskite solar cell according to an embodiment of this application before and after reduction.

[0025] Figure 2 This is a schematic diagram of a perovskite solar cell according to one embodiment of this application. Detailed Implementation

[0026] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the perovskite solar cell and its fabrication method of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of essentially identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0027] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0028] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0029] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0030] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0031] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0032] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0033] Nickel oxide, as the most commonly used inorganic hole transport layer material in inverted perovskite solar cells, is a preferred candidate for the industrialization of perovskite solar cells. However, the trivalent nickel on the surface of the nickel oxide hole transport layer reacts with A-site cations in the perovskite precursor solution, resulting in A-site vacancies and excess lead halide residue at the interface. This increases interfacial charge recombination and reduces the turn-on voltage of the perovskite solar cell. Simultaneously, the erosion of the perovskite light-absorbing layer by water and oxygen can affect the stability of the device to some extent.

[0034] Through extensive experiments, the inventors of this application discovered that when the surface of a nickel oxide film is treated with a reducing gas, the surface-charged nickel oxide is reduced to nano-sized elemental nickel particles. By utilizing the tunneling effect of the thin-layer metallic nickel, the interfacial recombination is reduced while the influence of water and oxygen on the perovskite light-absorbing layer is suppressed, thereby further improving stability while ensuring performance.

[0035] In one embodiment of this application, a perovskite solar cell is provided, comprising a transparent conductive glass substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and electrodes. The hole transport layer is a nickel oxide hole transport layer, wherein elemental nickel is present on the surface of the hole transport layer in contact with the perovskite light-absorbing layer, and the ratio of elemental nickel to trivalent nickel on the surface of the hole transport layer in contact with the perovskite light-absorbing layer is 85:15-99:1, optionally 90:10-99:1, and further optionally 95:5-99:1.

[0036] Although the mechanism is not yet clear, the applicant unexpectedly discovered that by introducing elemental nickel into the surface where the nickel oxide hole transport layer contacts the perovskite light-absorbing layer, the reaction between the high-valence nickel in the nickel oxide hole transport layer and the A-site cations in the perovskite light-absorbing layer is reduced. This results in the absence of lead halide residue at the interface between the nickel oxide hole transport layer and the perovskite light-absorbing layer, reducing non-radiative recombination at the interface and improving the turn-on voltage of the perovskite solar cell, thereby improving the photoelectric conversion efficiency of the perovskite solar cell. At the same time, the introduction of elemental nickel can further suppress the influence of water and oxygen on the perovskite light-absorbing material, thereby improving the long-term stability of the perovskite solar cell.

[0037] like Figure 1 As shown, this application reduces the nickel oxide hole transport layer in situ, thereby removing the charged nickel, especially trivalent nickel (Ni) from the surface of the hole transport layer. 3+ The nickel oxide hole transport layer is reduced to elemental nickel, which reduces the reaction between trivalent nickel in the nickel oxide hole transport layer and A-site cations (HA in this embodiment, where HA is formamidinium cation or methylamine cation) in the perovskite light-absorbing layer. This results in the absence of lead halide (lead iodide in this embodiment) residue at the interface between the nickel oxide hole transport layer and the perovskite light-absorbing layer, thereby improving the photoelectric conversion efficiency of the perovskite solar cell.

[0038] In the embodiments of this application, the perovskite light-absorbing layer and the perovskite layer can be used interchangeably.

[0039] In some embodiments, trivalent nickel is not present on the surface of the hole transport layer that contacts the perovskite light-absorbing layer.

[0040] In some embodiments, the hole transport layer is a nickel oxide hole transport layer.

[0041] Nickel oxide is a commonly used hole transport layer material in inverted perovskite solar cells. Nickel oxide is generally represented as NiOx, which can represent one or more of nickel oxide, nickel trioxide, etc.

[0042] In some embodiments, the hole transport layer may contain substances such as NiO, Ni(OH)2, Ni2O3, and NiOOH.

[0043] In some embodiments, there is no interface passivation material on the surface of the hole transport layer that contacts the perovskite light-absorbing layer, and optionally, no p-type interface passivation material. In other words, there is no passivation layer between the hole transport layer and the perovskite light-absorbing layer, i.e., no passivation layer for passivating the hole transport layer. Optionally, there are no other layers between the hole transport layer and the perovskite light-absorbing layer.

[0044] Even without a passivation layer between the hole transport layer and the perovskite light-absorbing layer, the performance and stability of the perovskite solar cell can still be guaranteed according to this application, and it also saves material costs, time costs and environmental costs, thus having good economic benefits.

[0045] In some embodiments, the thickness of the hole transport layer is 10-100 nm.

[0046] In some embodiments, the perovskite solar cell is an inverted perovskite solar cell.

[0047] In some embodiments, the transparent conductive glass substrate comprises glass and a transparent conductive oxide, wherein the transparent conductive oxide is selected from fluorine-doped tin oxide (FTO), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), indium zinc oxide (IZO), etc., the thickness of the glass is 0.1-3 cm, and the thickness of the transparent conductive oxide is 100-1000 nm.

[0048] like Figure 2 As shown, in an inverted perovskite solar cell, a transparent conductive glass substrate (in this embodiment, the transparent conductive oxide is ITO), a nickel oxide hole transport layer (i.e., a nickel oxide layer), a perovskite light-absorbing layer, an electron transport layer, and an electrode (in this embodiment, a metal electrode) are arranged sequentially from bottom to top, wherein elemental nickel is present on the surface of the nickel oxide hole transport layer that is in contact with the perovskite light-absorbing layer.

[0049] In some embodiments, the perovskite light-absorbing layer is made of the chemical formula ABX3 or A2CDX6, where A is an inorganic, organic, or organic-inorganic mixed cation, optionally a methylamino group (CH3NH3). + (MA) + ), formamidinyl (HC(NH2)2 + (FA) + ), cesium ion (Cs + ) and rubidium (Rb + At least one of the following, further optionally methylamino (CH3NH3) + ) or formamidinyl (HC(NH2)2 +B is an inorganic, organic, or mixed organic-inorganic cation, optionally a divalent metal ion Pb. 2+ and Sn 2+ At least one of the following; C is an inorganic, organic, or mixed organic-inorganic cation, optionally a monovalent metal ion Ag. + etc.; D is an inorganic, organic, or mixed organic-inorganic cation, optionally a trivalent metal ion bismuth cation Bi. 3+ Antimony cation Sb 3+ Indium cations In 3+ etc.; X is an inorganic, organic, or mixed organic-inorganic anion, optionally one or more of a halide anion and a carboxylate anion, and further optionally a bromide ion (Br₂). - ) or iodide ions (I - ).

[0050] In some embodiments, the band gap of the perovskite light-absorbing layer is 1.20 eV-2.30 eV.

[0051] In some embodiments, the thickness of the perovskite light-absorbing layer is 200 nm to 1000 nm.

[0052] In some embodiments, the material of the electron transport layer is at least one of the following materials and their derivatives, as well as materials obtained by doping or passivation: [6,6]-phenyl-C 61 methyl butyrate (PC) 61 BM), [6,6]-phenyl-C 71 methyl butyrate (PC) 71 BM), fullerene C60 (C60), fullerene C70 (C70), tin dioxide (SnO2), zinc oxide (ZnO), etc.

[0053] In some embodiments, the thickness of the electron transport layer is 30-120 nm.

[0054] In some embodiments, the electrode is made of an organic, inorganic, or organic-inorganic mixed conductive material, optionally Ag, Cu, C, Au, Al, ITO, AZO, BZO, or IZO.

[0055] In some embodiments, the thickness of the electrode is 10-200 nm.

[0056] In some implementations, a passivation layer may be present between the perovskite light-absorbing layer and the electron transport layer to passivate defects at the interface between the two.

[0057] In some implementations, a passivation layer may be present between the electron transport layer and the electrodes to improve the performance of the perovskite solar cell.

[0058] In one embodiment of this application, a method for preparing a perovskite solar cell is proposed, comprising the following steps:

[0059] Step 1: Provide a transparent conductive glass substrate;

[0060] Step 2: Prepare a hole transport layer on the transparent conductive glass substrate;

[0061] Step 3: Place the transparent conductive glass substrate with the hole transport layer prepared thereon in a sealed device, and introduce carrier gas and reducing gas to react;

[0062] Step 4: Prepare a perovskite light-absorbing layer on the hole transport layer processed in Step 3;

[0063] Step 5: Prepare an electron transport layer on the perovskite light-absorbing layer;

[0064] Step 6: Fabricate electrodes on the electron transport layer to obtain a perovskite solar cell.

[0065] The perovskite solar cell comprises a transparent conductive glass substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and electrodes. The hole transport layer is a nickel oxide hole transport layer. Elemental nickel is present on the surface of the hole transport layer in contact with the perovskite light-absorbing layer. On the surface of the hole transport layer in contact with the perovskite light-absorbing layer, the ratio of elemental nickel to trivalent nickel is 85:15-99:1, optionally 90:10-99:1, and further optionally 95:5-99:1.

[0066] Therefore, this application utilizes a reducing gas to perform in-situ reduction of the nickel oxide hole transport layer, reducing the charged nickel on the surface of the hole transport layer to elemental nickel. The gas used for in-situ reduction of the nickel oxide hole transport layer surface also includes a carrier gas. The introduction of the carrier gas not only ensures the removal of generated water vapor but also guarantees the smooth progress of the experiment. Furthermore, the carrier gas and reducing gas used are introduced into the sealed device in a single pass, effectively ensuring that the surface of the nickel oxide hole transport layer is uniformly reduced.

[0067] In the embodiments of this application, in step 1, the transparent conductive glass substrate needs to be cleaned before use, for example, by ultrasonic cleaning with deionized water, acetone, isopropanol, etc.

[0068] In some embodiments, the method for preparing the hole transport layer in step 2 includes, but is not limited to, sol-gel method, sputtering method, spin-coating nickel oxide nanoparticle method, etc.

[0069] In some embodiments, step 2 involves preparing the hole transport layer using a sol-gel method, including the following steps: a solution containing nickel is dropped onto a transparent conductive glass substrate, optionally in an amount of 0.01-1 mL, then rotated at a speed of 1000-8000 rpm for 10-60 seconds, followed by annealing. Optionally, the annealing procedure is as follows: holding at 80°C for 1-100 minutes, then raising the temperature to 200-500°C over 10-50 minutes, maintaining at 200-500°C for 0.1-5 hours, and then cooling to below 100°C; the hole transport layer is obtained after annealing.

[0070] In some embodiments, in step 2, the hole transport layer is prepared by spray pyrolysis, including the following operations: dissolving a nickel-containing substance in a solvent to obtain a nickel-containing solution, stirring, filtering, taking the supernatant, spraying it onto the surface of a conductive glass, and then sintering it. Optionally, the sintering temperature range is 100-500℃, optionally 300-400℃, and the sintering time is 10-120 minutes, optionally 60-80 minutes; after cooling, the hole transport layer is obtained.

[0071] In some embodiments, in step 2, a hole transport layer is prepared by magnetron sputtering, wherein oxygen and argon are used, and the volume ratio of oxygen to argon is 1:20 to 1:5, optionally 1:12 to 1:8.

[0072] In some embodiments, the nickel-containing substance is selected from nickel oxide, nickel nitrate, nickel acetate, nickel acetylacetone, or mixtures thereof.

[0073] The nickel oxide may be nickel oxide nanoparticles.

[0074] The nickel nitrate may be aqueous nickel nitrate, such as nickel nitrate hexahydrate.

[0075] The nickel acetate may be aqueous nickel acetate, such as nickel acetate tetrahydrate.

[0076] The solvent used to prepare solutions containing nickel is one or more selected from methanol, ethylenediamine, and water.

[0077] In some embodiments, in step 3, the reducing gas is selected from at least one of hydrogen, carbon monoxide, hydrogen sulfide, sulfur dioxide, hydrogen iodide, and ammonia.

[0078] In some embodiments, in step 3, the carrier gas is selected from at least one of nitrogen and argon.

[0079] In some embodiments, in step 3, the ratio of the carrier gas to the reducing gas is 99:1 to 70:30.

[0080] When the ratio of the carrier gas to the reducing gas is within a given range, the surface reduction effect of the nickel oxide hole transport layer can be further improved. If the concentration of the reducing gas is too high, it will reduce an excessively thick nickel oxide hole transport layer, which is detrimental to hole transport and poses a significant risk; if the concentration of the reducing gas is too low, the reaction time will be too long. Considering both efficiency and safety, the ratio of the carrier gas to the reducing gas can be optionally between 90:10 and 80:20.

[0081] In some embodiments, the reaction time in step 3 is 10-60 minutes. Taking into account both photoelectric conversion efficiency and cost, the reaction time may optionally be 20-30 minutes.

[0082] In some embodiments, in step 3, the reaction temperature is 150°C-250°C, optionally 180°C-220°C.

[0083] In the embodiments of this application, in step 4, a perovskite light-absorbing layer is prepared using conventional techniques in the art. For example, the perovskite light-absorbing layer can be prepared by the following method: preparing a perovskite precursor solution; spin-coating the perovskite precursor solution onto the hole transport layer treated in step 3 at a rate of 1000-5000 rpm for 10-60 seconds; annealing at 80-200°C for 10-120 minutes to obtain the perovskite light-absorbing layer. The perovskite precursor solution is prepared, for example, by dissolving a perovskite precursor material (e.g., at least one of formamidine iodide, lead iodide, methyl bromide, methyl iodide, cesium iodide, lead bromide, etc.) in a solvent (e.g., dimethylformamide (DMF), dimethyl sulfoxide (DMSO), etc.), stirring until homogeneous, filtering, and taking the supernatant.

[0084] In the embodiments of this application, in step 5, the electron transport layer is prepared using conventional techniques in the art. For example, spin coating, vapor deposition, etc., can be used to prepare the electron transport layer.

[0085] In the embodiments of this application, in step 6, the electrode can be prepared using methods conventional in the art. For example, the electrode can be prepared by vapor deposition.

[0086] Example

[0087] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0088] Example 1

[0089] Step 1: Take an ITO conductive glass with dimensions of 2.0cm × 2.0cm (glass thickness of 1.1mm, ITO thickness of 100nm), and remove 0.35cm of ITO from each of the opposite ends by laser etching to expose the glass substrate; ultrasonically clean the etched ITO conductive glass once with water, acetone, and isopropanol in sequence; blow the solvent off the ultrasonically cleaned ITO conductive glass under a nitrogen gun and place it in an ultraviolet ozone generator for further cleaning;

[0090] Step 2: Spin-coat an aqueous solution of 10 mg / mL nickel oxide nanoparticles (particle size 10 nm) at a rate of 4000 rpm onto the UV ozone-treated ITO conductive glass, and anneal it on a hot plate at 100 °C for 30 minutes to obtain a hole transport layer with a thickness of 30 nm.

[0091] Step 3: Place the ITO conductive glass with the hole transport layer on the hot stage in a sealed glove box, and introduce argon as the carrier gas and hydrogen as the reducing gas in a ratio of 98:2. Keep the temperature of the hot stage at 200°C and control the reaction time to 30 minutes. After the reaction is completed, place the sheet in a vacuum dryer and repeatedly pump and fill the dryer to remove any hydrogen or other substances that may remain on the surface of the sheet.

[0092] Step 4: Spin-coat the perovskite precursor solution onto the hole transport layer treated in Step 3 at a rate of 3000 rpm. The perovskite precursor solution is prepared by dissolving 80 mg formamidine iodide (FAI), 223 mg lead iodide (PbI2), and 15 mg methyl chloroamine (MACl) in 1 mL of an organic solvent, with the organic solvent being DMF and DMSO in a ratio of 4:1. Anneal at 100 °C for 30 minutes and cool to room temperature to obtain the FA system perovskite light-absorbing layer with a thickness of 550 nm.

[0093] Step 5: Spin-coat the prepared perovskite light-absorbing layer with 20 mg / mL PC at a rate of 2000 rpm. 61 An electron transport layer with a thickness of 80 nm was obtained by annealing a chlorobenzene solution of BM at 100 °C for 10 minutes; then, a passivation layer with a thickness of 8 nm was obtained by spin-coating a 0.5 mg / mL solution of copper bath (BCP) in isopropanol at a rate of 5000 rpm.

[0094] Step 6: In the vapor deposition machine, at 1×10 -5 Under a vacuum of Pa, on the BCP passivation layer, with The electrode was obtained by evaporating 80 nm of Ag at a certain rate.

[0095] The perovskite solar cell described in this application is obtained through the above steps.

[0096] Examples 2-5

[0097] The perovskite solar cells were prepared in accordance with Example 1, except that the reaction times in step 3 were 10 minutes, 20 minutes, 40 minutes and 60 minutes, respectively.

[0098] Examples 6-7

[0099] The fabrication of the perovskite solar cell was generally carried out in accordance with Example 1, except that in step 3, the carrier gas and reducing gas were nitrogen and carbon monoxide, and nitrogen and ammonia, respectively.

[0100] Examples 8-11

[0101] The fabrication of the perovskite solar cell was generally carried out in accordance with Example 1, except that in step 3, the ratio of carrier gas to reducing gas was 99:1, 90:10, 80:20 and 70:30, respectively.

[0102] Examples 12-15

[0103] The fabrication of the perovskite solar cell was generally carried out in accordance with Example 1, except that in step 3, the hot stage temperature was maintained at 150°C, 180°C, 220°C and 250°C respectively.

[0104] Comparative Example 1

[0105] The fabrication of the perovskite solar cell was generally carried out in accordance with Example 1, except that step 3 was not performed.

[0106] Comparative Example 2

[0107] The fabrication of the perovskite solar cell was generally carried out in accordance with Example 1, except that the reaction time in step 3 was 5 minutes.

[0108] Comparative Example 3

[0109] The fabrication of the perovskite solar cell was generally carried out in accordance with Example 1, except that step 3 was omitted, and a commonly used passivation layer was added between the hole transport layer and the perovskite light-absorbing layer. This passivation layer was made of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) with a thickness of 2 nm.

[0110] Performance testing

[0111] 1. Test of the molar ratio of elemental nickel to trivalent nickel on the hole transport layer surface

[0112] The molar ratio of elemental nickel to trivalent nickel on the surface of the hole transport layer was determined using XPS.

[0113] 2. Measurement of photoelectric conversion efficiency

[0114] The test was conducted according to the national standard IEC61215, which was performed under illumination using a digital source meter. The light source was provided by a solar simulator, and the light emitted by the source conformed to the AM 1.5G standard solar spectrum.

[0115] 3. Stability determination

[0116] The photoelectric conversion efficiency of the battery was continuously measured, and the photoelectric conversion efficiency on day 3 and day 30 was taken as the short-term efficiency and long-term efficiency of the battery.

[0117] The perovskite solar cells obtained in the above embodiments and comparative examples were tested according to the above process, and the specific values ​​are shown in Table 1.

[0118]

[0119] Compared with Comparative Examples 1-2, the perovskite solar cells prepared in Examples 1-15 all exhibited higher photoelectric conversion efficiency and better 30-day stability. This demonstrates that reducing the surface of the nickel oxide hole transport layer in contact with the perovskite light-absorbing layer to achieve a nickel-to-trivalent nickel ratio of 85:15-99:1 on this surface can improve the long-term stability of the perovskite solar cells.

[0120] By comparing Examples 1-15, which involve reducing the nickel oxide hole transport layer, with Comparative Example 3, which uses conventional methods for passivation, it can be seen that the perovskite solar cells prepared by reducing the nickel oxide hole transport layer significantly improve long-term stability compared with conventional solar cells. Moreover, the method is simple and efficient, saving time and material costs.

[0121] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A perovskite solar cell comprising a transparent conductive glass substrate, a hole transport layer, a perovskite light absorbing layer, an electron transport layer and an electrode, the hole transport layer being a nickel oxide hole transport layer, wherein, Elemental nickel is present on the surface of the hole transport layer that contacts the perovskite light-absorbing layer, and the ratio of elemental nickel to trivalent nickel on the surface of the hole transport layer that contacts the perovskite light-absorbing layer is 85:15-99:

1.

2. The perovskite solar cell according to claim 1, wherein The ratio of elemental nickel to trivalent nickel is 90:10-99:

1.

3. The perovskite solar cell according to claim 1 or 2, wherein The ratio of elemental nickel to trivalent nickel is 95:5-99:

1.

4. The perovskite solar cell according to claim 1 or 2, wherein There is no interface passivation material on the surface of the hole transport layer that contacts the perovskite light-absorbing layer.

5. The perovskite solar cell according to claim 1 or 2, wherein There is no p-type interface passivation material on the surface of the hole transport layer that contacts the perovskite light-absorbing layer.

6. The perovskite solar cell according to claim 1 or 2, wherein, The perovskite solar cell is an inverted perovskite solar cell.

7. The perovskite solar cell according to claim 1 or 2, wherein, The hole transport layer is a nickel oxide hole transport layer.

8. The perovskite solar cell according to claim 1 or 2, wherein, The thickness of the hole transport layer is 10-100 nm.

9. The perovskite solar cell according to claim 1 or 2, wherein, The transparent conductive glass substrate comprises glass and a transparent conductive oxide, wherein the transparent conductive oxide is selected from at least one of fluorine-doped tin oxide, indium tin oxide, aluminum-doped zinc oxide, boron-doped zinc oxide, and indium zinc oxide.

10. The perovskite solar cell according to claim 9, wherein, The thickness of the transparent conductive oxide is 100-1000 nm.

11. The perovskite solar cell according to claim 1 or 2, wherein, The chemical formula of the perovskite light-absorbing layer is ABX3 or A2CDX6, where A is an inorganic or organic or organic-inorganic mixed cation, B is an inorganic or organic or organic-inorganic mixed cation, C is an inorganic or organic or organic-inorganic mixed cation, D is an inorganic or organic or organic-inorganic mixed cation, and X is an inorganic or organic or organic-inorganic mixed anion.

12. The perovskite solar cell according to claim 11, wherein, A is at least one of methylamino, formamidinyl, cesium ion, and rubidium.

13. The perovskite solar cell according to claim 11, wherein, A is either methylamino or formamidinyl.

14. The perovskite solar cell according to claim 11, wherein, B is a divalent metal ion Pb 2+ and at least one of Sn 2+ and Sn.

15. The perovskite solar cell according to claim 11, wherein, C is a monovalent metal ion Ag + .

16. The perovskite solar cell according to claim 11, wherein, D is at least one of a trivalent metal ion, a bismuth cation Bi 3+ , an antimony cation Sb 3+ , an indium cation In 3+ .

17. The perovskite solar cell according to claim 11, wherein, X is one or more of a halide anion and a carboxylate anion.

18. The perovskite solar cell according to claim 11, wherein, X is either a bromide ion or an iodide ion.

19. The perovskite solar cell according to claim 1 or 2, wherein, The thickness of the perovskite light-absorbing layer is 200 nm-1000 nm.

20. The perovskite solar cell according to claim 1 or 2, wherein, The material of the electron transport layer is at least one of the following materials, derivatives thereof, and materials obtained by doping or passivating thereof: [6,6]-phenyl-C 61 - methyl butanoate, [6,6]-phenyl-C 71 - methyl butanoate, fullerene C60, fullerene C70, tin dioxide, zinc oxide.

21. The perovskite solar cell according to claim 1 or 2, wherein, The thickness of the electron transport layer is 30-120 nm.

22. The perovskite solar cell according to claim 1 or 2, wherein, The electrode is made of organic, inorganic, or organic-inorganic mixed conductive material.

23. The perovskite solar cell according to claim 1 or 2, wherein, The electrode material is Ag, Cu, C, Au, Al, ITO, AZO, BZO, or IZO.

24. The perovskite solar cell according to claim 1 or 2, wherein, The thickness of the electrode is 10-200 nm.

25. The perovskite solar cell according to claim 1 or 2, wherein, A passivation layer exists between the electron transport layer and the electrode.

26. A method for preparing a perovskite solar cell, comprising the following steps: Step 1: Provide a transparent conductive glass substrate; Step 2: Prepare a hole transport layer on the transparent conductive glass substrate; Step 3: Place the transparent conductive glass substrate with the hole transport layer prepared thereon in a sealed device, and introduce carrier gas and reducing gas to react; Step 4: Prepare a perovskite light-absorbing layer on the hole transport layer processed in Step 3; Step 5: Prepare an electron transport layer on the perovskite light-absorbing layer; Step 6: Fabricate electrodes on the electron transport layer to obtain a perovskite solar cell. The perovskite solar cell comprises a transparent conductive glass substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and electrodes. The hole transport layer is a nickel oxide hole transport layer. Elemental nickel is present on the surface of the hole transport layer in contact with the perovskite light-absorbing layer, and the ratio of elemental nickel to trivalent nickel on the surface of the hole transport layer in contact with the perovskite light-absorbing layer is 85:15-99:

1.

27. The method according to claim 26, wherein, The ratio of elemental nickel to trivalent nickel is 90:10-99:

1.

28. The method according to claim 26 or 27, wherein, The ratio of elemental nickel to trivalent nickel is 95:5-99:

1.

29. The method according to claim 26 or 27, wherein, In step 3, the reducing gas is selected from at least one of hydrogen, carbon monoxide, hydrogen sulfide, sulfur dioxide, hydrogen iodide, and ammonia.

30. The method according to claim 26 or 27, wherein, In step 3, the carrier gas is selected from at least one of nitrogen and argon.

31. The method according to claim 26 or 27, wherein, In step 3, the ratio of the carrier gas to the reducing gas is 99:1 to 70:

30.

32. The method according to claim 26 or 27, wherein, In step 3, the reaction time is 10-60 minutes.

33. The method according to claim 26 or 27, wherein, In step 3, the reaction temperature is 150℃-250℃.

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