Solar cell and preparation method therefor, and photovoltaic assembly, power generation apparatus and electric apparatus

Abstract

Provided in the present disclosure are a solar cell, comprising a perovskite light-absorbing layer, wherein the average grain size of perovskite grains in the perovskite light-absorbing layer is 500 nm to 1500 nm, and the surface photovoltage of the perovskite light-absorbing layer that is measured by means of Kelvin probe force microscopy is greater than or equal to 0 mV and less than or equal to 60 mV. The present disclosure further relates to a preparation method for a solar cell, and a photovoltaic assembly comprising the solar cell, and a power generation apparatus and an electric apparatus.

Description

Solar cells and their preparation methods, photovoltaic modules, power generation devices, and electrical appliances.

[0001] Cross-reference to related applications

[0002] This disclosure is based on and claims priority to Chinese Patent Application No. 202411599126.5, filed on November 8, 2024, entitled “Solar Cell and Method for Preparation Thereof, Photovoltaic Module, Power Generation Device, and Power Consumption Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of battery technology, and in particular to a solar cell and its preparation method, a photovoltaic module, a power generation device, and a power consumption device. Background Technology

[0004] In recent years, global energy shortages and environmental pollution have become increasingly prominent, leading to growing attention on solar cells as an ideal renewable energy source. Solar cells, also known as photovoltaic cells, are devices that directly convert light energy into electrical energy through the photoelectric effect or photochemical effect.

[0005] Perovskite solar cells are solar cells that utilize perovskite materials as light-absorbing materials. Compared with other solar cells, perovskite solar cells stand out in the field of solar cells due to their advantages such as low cost, high efficiency, and simple manufacturing process.

[0006] However, the low open-circuit voltage and photoelectric conversion efficiency of perovskite solar cells hinder their practical application and industrialization. Therefore, improving the open-circuit voltage and photoelectric conversion efficiency of perovskite solar cells remains an urgent technical problem to be solved. Summary of the Invention

[0007] This disclosure is made in view of the above-mentioned problems, and its object is to provide a solar cell and a method for manufacturing the same, a photovoltaic module, a power generation device, and a power consumption device. The solar cell of this disclosure has improved open-circuit voltage and photoelectric conversion efficiency.

[0008] To achieve the above objectives, this disclosure provides a solar cell including a perovskite light-absorbing layer; wherein the average grain size of the perovskite grains in the perovskite light-absorbing layer is 500 nm to 1500 nm, and the surface photovoltage of the perovskite light-absorbing layer, measured by Kelvin probe force microscopy, is greater than or equal to 0 mV and less than or equal to 60 mV. The perovskite grain size and surface photovoltage being within the above range improve the open-circuit voltage and photoelectric conversion efficiency of the solar cell.

[0009] In some embodiments, the average grain size of the perovskite light-absorbing layer is between 500 nm and 1000 nm. This grain size range helps reduce grain boundaries in the system, thereby reducing non-radiative recombination within the perovskite and thus improving the open-circuit voltage of devices incorporating it.

[0010] In some embodiments, the surface photovoltage of the perovskite absorbing layer, measured by Kelvin probe force microscopy, is between 10 mV and 22 mV. The perovskite absorbing layer of this disclosure has high surface potential distribution uniformity, which is beneficial for improving the photoelectric conversion efficiency of devices including it.

[0011] In some embodiments, the roughness of the perovskite light-absorbing layer is from 10 nm to 50 nm. Therefore, the perovskite light-absorbing layer of this disclosure has high flatness, which is beneficial for improving the open-circuit voltage of devices including it.

[0012] In some embodiments, the perovskite light-absorbing layer includes thiocyanate ions (SCN). - Therefore, the thiocyanate ion exists in the perovskite phase and plays a role in passivating halogen vacancies by ion bonding with excess cations, thereby further reducing surface defects and thus improving the photoelectric conversion efficiency of solar cells.

[0013] In some embodiments, the perovskite light-absorbing layer further includes Lewis bases containing C=O double bonds and / or Lewis bases containing C=S double bonds. Thus, the lone pair electrons in O and S and the metal ions in the perovskite, such as Pb ions, form coordination interactions, further reducing defects and improving the photoelectric conversion efficiency of the device.

[0014] In some embodiments, the amount of thiocyanate ions in the perovskite light-absorbing layer is 0.001 mol to 0.006 mol relative to 1 mol of perovskite. This is more conducive to the effective passivation effect of thiocyanate ions, reducing surface defects and thus improving the photoelectric conversion efficiency of the device.

[0015] In some embodiments, the amount of Lewis bases containing C=O double bonds and / or Lewis bases containing C=S double bonds in the perovskite light-absorbing layer is 0.001 mol to 0.01 mol relative to 1 mol of perovskite. This allows the lone pair electrons in O and S to effectively coordinate with metal ions in the perovskite, such as Pb ions, reducing defects and further improving the photoelectric conversion efficiency of the device.

[0016] In some embodiments, the perovskite light-absorbing layer comprises at least one of the compounds shown in formula (I) and formula (II):

[0017] [A][B][X]3 (I),

[0018] [A]2[C][D][X]6 (II);

[0019] Wherein, A includes at least one of inorganic or organic monovalent cations, B includes at least one of inorganic or organic divalent cations, C includes at least one of inorganic or organic monovalent cations, D includes at least one of inorganic or organic trivalent cations, and X includes at least one of inorganic or organic monovalent anions.

[0020] In some embodiments, the perovskite light-absorbing layer comprises a compound represented by formula (I):

[0021] [A][B][X]3 (I);

[0022] A includes FA, MA, and Cs. + At least one of them, B is Sn 2+ and / or Pb 2+ X includes Cl - ,Br - I - At least two of them, FA represents (H2N=CH-NH2). + MA represents CH3NH3 + This is more conducive to increasing the perovskite grain size and improving the surface smoothness of the perovskite light-absorbing layer, thereby improving the open-circuit voltage and photoelectric conversion efficiency of the solar cell.

[0023] In some embodiments, the solar cell further includes a first electrode and a second electrode, the first electrode having opposite polarities to the second electrode. Thus, the two electrodes with opposite polarities can respectively transport electrons and holes generated in the perovskite light-absorbing layer to the outside to form a circuit.

[0024] In some embodiments, the solar cell further includes a first electrode, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a second electrode, which are stacked sequentially. Thus, the hole transport layer and the electron transport layer facilitate the extraction and transport of holes and electrons generated by the perovskite light-absorbing layer to the first electrode and the second electrode, respectively, forming a loop via an external circuit, which can then be used to drive a load.

[0025] The second aspect of this disclosure provides a method for fabricating a solar cell, including the preparation of a perovskite light-absorbing layer. The preparation of the perovskite light-absorbing layer includes: preparing a perovskite precursor solution, wherein the perovskite precursor solution comprises a perovskite precursor compound, a thiocyanate ion, and a Lewis base containing C=O bonds and / or a Lewis base containing C=S bonds; and growing the perovskite precursor solution into perovskite grains, followed by annealing.

[0026] In this disclosure, by adding thiocyanate-containing compounds and Lewis bases containing C=O bonds and / or C=S bonds during the preparation of the perovskite light-absorbing layer, the Lewis bases containing C=O bonds and / or C=S bonds coordinate with ions in the perovskite precursor to form an intermediate phase, thus slowing down the perovskite crystallization rate. Simultaneously, the thiocyanate ions react in the perovskite system to generate HSCN gas, which facilitates grain boundary dissolution, causing small grains to fuse and grow larger, thereby further increasing the grain size and achieving the effect of atmospheric annealing. Therefore, by adding the above two types of substances during the preparation process, the perovskite grain size can be significantly increased.

[0027] In some embodiments, the amount of thiocyanate in the perovskite precursor solution is 0.005 mol to 0.05 mol relative to 1 mol of perovskite precursor. This facilitates the creation of an effective HSCN gas atmosphere for the crystallization process by thiocyanate, dissolving grain boundaries, causing small grains to fuse and grow larger, while also allowing some to remain in the bulk phase, further contributing to passivation.

[0028] In some embodiments, the amount of Lewis bases containing C=O bonds and / or Lewis bases containing C=S bonds in the perovskite precursor solution is 0.01 mol to 0.1 mol relative to 1 mol of perovskite precursor. This effectively exerts coordination, slows down perovskite crystallization, and promotes grain size increase.

[0029] In some embodiments, the molar ratio of thiocyanate to Lewis bases containing C=O bonds and / or Lewis bases containing C=S bonds in the perovskite precursor solution is 1:(1-4). This further facilitates slowing down the crystallization of perovskite and increasing the grain size.

[0030] In some embodiments, the annealing temperature is 50°C to 80°C. This helps to maintain the residual amount of thiocyanate in the system within an appropriate range, so that the residual thiocyanate ions passivate halogen vacancies through ionic bonding with excess cations, reducing surface defects and improving photoelectric conversion efficiency.

[0031] In some embodiments, the annealing time is 3–10 minutes. This further helps to maintain the residual amount of thiocyanate in the system within an appropriate range, thus passivating halogen vacancies.

[0032] In some embodiments, the thiocyanate-containing compound includes one or more of ammonium thiocyanate, guanidine thiocyanate, formamidinium thiocyanate, methylamine thiocyanate, cesium thiocyanate, potassium thiocyanate, cuprous thiocyanate, and lead thiocyanate.

[0033] In some embodiments, the Lewis base containing a C=O bond comprises one or more amino groups. In some embodiments, the Lewis base containing a C=S bond comprises one or more amino groups.

[0034] In some embodiments, Lewis bases containing C=O bonds include one or more of urea, 1,1-dimethylurea, 1,3-dimethylurea, ethylurea, or (hydroxymethyl)urea. In some embodiments, Lewis bases containing C=S bonds include one or more of thiourea, N-methylthiourea, or trimethylthiourea.

[0035] A third aspect of this disclosure provides a photovoltaic module comprising a solar cell provided in the first aspect or a solar cell obtained according to the method of the second aspect.

[0036] The fourth aspect of this disclosure provides a power generation device, which includes a solar cell provided in the first aspect or a solar cell obtained according to the method of the second aspect.

[0037] The fifth aspect of this disclosure provides an electrical device that includes a solar cell provided in the first aspect or a solar cell obtained according to the method of the second aspect. Attached Figure Description

[0038] Figure 1 shows a schematic diagram of the structure of a solar cell according to an embodiment of the present disclosure.

[0039] Figure 2 shows scanning electron microscope images of the perovskite light-absorbing layer of Example 1 of this disclosure (a) Comparative Example 1, (b) Comparative Example 2, (c) Comparative Example 3, and (d) Example 1.

[0040] Figure 3 shows scanning electron microscope images of cross sections of the perovskite light-absorbing layer of Example 1 of this disclosure (a) Comparative Example 1, (b) Comparative Example 2, (c) Comparative Example 3, and (d) Example 1.

[0041] Explanation of reference numerals in the attached figures: 10: Solar cell; 11: First electrode; 12: Second electrode; 13: Perovskite light-absorbing layer; 151: Hole transport layer; 152: Electron transport layer. Detailed Implementation

[0042] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the solar cell, its fabrication method, photovoltaic module, power generation device, and power consumption device of this disclosure. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically 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 to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter of the claims.

[0043] The "range" disclosed in this disclosure is defined by a lower limit and an upper limit, whereby a given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the 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 expected. Furthermore, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​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 disclosure, 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, integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0044] Unless otherwise specified, all embodiments and optional embodiments of this disclosure can be combined to form new technical solutions.

[0045] Unless otherwise specified, all technical features and optional technical features of this disclosure can be combined to form new technical solutions.

[0046] Unless otherwise specified, all steps of this disclosure may be performed sequentially or randomly, preferably sequentially. For example, if a method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if it is mentioned that the method may also include step (c), it means 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.

[0047] Unless otherwise specified, the terminology used in this disclosure has the common meaning as commonly understood by those skilled in the art.

[0048] Unless otherwise specified, the values ​​of the parameters mentioned in this disclosure can be determined using various test methods commonly used in the art, for example, according to the test methods given in this disclosure.

[0049] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprise” and / or “comprising,” when used in this specification, identify the presence of features, integers, steps, operations, elements, and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0050] The term "electrode" refers to a region or layer that is composed of or is substantially composed of electrode material.

[0051] As used in this disclosure, the term "layer" refers to any substantially layered structure. A layer may have a thickness that varies over its length. Typically, the thickness of a layer is approximately constant. As used in this disclosure, "thickness" of a layer refers to the average thickness of the layer. The thickness of a layer can be measured using methods conventional in the art. For example, it can be measured using a Zygo NewView 9000 white light interferometer.

[0052] Unless otherwise specified, the term "arranged / set on" means to provide or set one component on another component. The first component may be provided directly on or set on the second component, or a third component may be present between the first and second components. For example, if the first layer is set on the second layer, this includes cases where there is an intermediate third layer between the first and second layers.

[0053] In this disclosure, the term "surface photovoltage (SPV)" refers to the potential difference obtained after scanning the surface of an object under illumination and darkness using Kelvin probe force microscopy (KPFM). For example, after stripping other layers of a solar cell to expose the perovskite light-absorbing layer, the contact potential difference (CPD) between the AFM tip and the perovskite light-absorbing layer is measured using KPFM under darkness and 430 nm laser illumination. The difference in CPD under darkness and illumination is called the surface photovoltage (SPV), i.e., SPV = CPD. 光照 -CPD 黑暗 .

[0054] In this disclosure, the term "average grain size" refers to the average grain size obtained by scanning electron microscopy (SEM) of 100 grains, using the longest diagonal of the grain as the grain size. Exemplarily, the average grain size can be obtained through the following steps: 1) Sample preparation: Place the perovskite layer sample to be tested on a clean surface; clean the sample surface using a dry nitrogen gun to remove any dust or contaminants; fix the cleaned sample on a sample holder, ensuring the sample surface is flat and in good contact with the holder; 2) SEM sample clamping: Fix the sample holder to the SEM sample stage using conductive tape; ensure good contact between the sample and the sample stage to avoid charge accumulation in a high vacuum environment; 3) SEM parameter settings: Set an appropriate accelerating voltage (typically between 5-20 kV) according to the SEM equipment's operating manual; set the working distance (WD) and magnification. 4) SEM Imaging: Image the sample in SEM to obtain SEM images of the perovskite film surface, ensuring that the images contain a sufficient number of grains for statistical analysis; 5) Grain Size Measurement: Use SEM software tools or image analysis software to measure the longest dimension of each grain in the image; record the size data of at least 100 grains to ensure the reliability of the statistical results; 6) Data Processing: Calculate the average of all measured grain sizes to determine the average grain size of the perovskite film; the automatic measurement function of image analysis software can be used to accelerate this process.

[0055] In this disclosure, "roughness" refers to the unevenness of a surface with small spacing and minute peaks and valleys. For example, roughness can be obtained by: 1) acquiring surface height data of the perovskite light-absorbing layer sample using atomic force microscopy (AFM); 2) converting the acquired height data into a three-dimensional surface model; and 3) calculating the average height Z of all points within the measurement area. mean ;4) For each point within the measurement area, calculate the absolute value of the deviation of its height from the average height, |Z|. (x,y) -Z mean |;5) Add the absolute values ​​of the height deviations of all points to obtain the sum of absolute deviations; 6) Divide the sum of absolute deviations by the area of ​​the measurement region to obtain the surface roughness (Ra value).

[0056] Perovskite solar cells are solar cells that utilize perovskite material as the light-absorbing material. Compared with other solar cells, perovskite solar cells have high photoelectric conversion efficiency. Unless otherwise specified, in the following text, a solar cell refers to a solar cell whose light-absorbing layer contains perovskite material; it can also be called a perovskite solar cell.

[0057] The photoelectric conversion principle of perovskite solar cells is as follows: Incident light (e.g., sunlight) enters the device from the light-transmitting side, then reaches the perovskite light-absorbing layer and is absorbed by it. Under the excitation of the incident light, the perovskite light-absorbing layer generates electron-hole pairs. Under the action of an electric field, the holes and electrons separate. The electrons are transferred to one electrode, while the holes are transferred to the other electrode. Subsequently, a loop is formed through the external circuit, which can be used to drive the load.

[0058] However, in perovskite solar cells, the presence of surface defects leads to nonradiative recombination of charge carriers, negatively impacting the cell's photoelectric performance and open-circuit voltage. The rapid crystallization rate and small grain size of perovskite, resulting in numerous grain boundaries, are the main reasons for the increased interface defects. In related technologies, grain size can be increased by improving the annealing process, but this process is complex and lacks stability in mass production. Therefore, a technique is still needed to improve grain size to enhance the open-circuit voltage and photoelectric conversion efficiency of perovskite solar cells.

[0059] Based on this, the present disclosure provides a solar cell and a method for its fabrication, a photovoltaic module, a power generation device, and a power consumption device. The present disclosure and optional embodiments are described in more detail below.

[0060] Solar cells

[0061] The first aspect of this disclosure provides a solar cell. The solar cell includes a perovskite light-absorbing layer; wherein the average grain size of the perovskite light-absorbing layer is 500 nm to 1500 nm, and the surface photovoltage of the perovskite light-absorbing layer, measured by Kelvin probe force microscopy, is greater than or equal to 0 mV and less than or equal to 60 mV.

[0062] For example, the average grain size of the perovskite light-absorbing layer is 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1200 nm, 1400 nm, 1500 nm, or any value within a range of any two values, but is not limited thereto. For example, the surface photovoltage of the perovskite light-absorbing layer, measured by Kelvin probe force microscopy, is below 60 mV, 50 mV, 40 mV, 30 mV, 25 mV, or 22 mV, for example, 21 mV, 20 mV, 15 mV, 11 mV, 10 mV, 8 mV, 5 mV, 2 mV, or 0 mV, or any value within a range of any two values, but is not limited thereto. Optionally, the surface photovoltage of the perovskite light-absorbing layer, measured by Kelvin probe force microscopy, is below 22 mV, such as 10 mV to 22 mV.

[0063] In the solar cell of this disclosure, the perovskite grains in the perovskite light-absorbing layer have relatively large sizes, resulting in fewer grain boundaries and consequently fewer defects. This reduces non-radiative recombination within the perovskite, which is beneficial for improving the open-circuit voltage of the solar cell. Furthermore, the surface photovoltage remains within the aforementioned range, indicating that the surface potential of the perovskite light-absorbing layer changes little under illumination and dark conditions, demonstrating reduced surface defects and improved charge carrier extraction and transport efficiency. Therefore, the perovskite light-absorbing layer of this disclosure is a layer with fewer defects and larger grains, resulting in an improved open-circuit voltage and photoelectric conversion efficiency for the solar cell comprising it.

[0064] The average grain size of the perovskite light-absorbing layer disclosed herein can be determined using instruments and methods known in the art. For example, the surface morphology can be characterized using a scanning electron microscope (Sigma 300 scanning electron microscope from ZEISS GmbH, Germany), with the longest diagonal of the grain used as the grain size, and 100 grains measured, and the average value taken.

[0065] The surface photovoltage of the perovskite absorbing layer disclosed herein is the difference in potential between the illuminated and dark states of the perovskite absorbing layer surface, obtained by Kelvin probe force microscopy (KPFM). A smaller surface photovoltage indicates a smaller change in surface potential, suggesting reduced surface defects and improved efficiency in charge carrier extraction and transport.

[0066] In some embodiments, the average grain size of the perovskite grains is between 500 nm and 1000 nm. Perovskite grains within this range further reduce grain boundaries in the system, thereby reducing surface defects and thus contributing to improved photoelectric conversion efficiency of devices incorporating the perovskite.

[0067] In some embodiments, the surface photovoltage of the perovskite light-absorbing layer is between 10 mV and 22 mV. Therefore, the surface potential difference of the perovskite light-absorbing layer of this disclosure is small under illumination and dark conditions, indicating fewer surface defects and improved charge carrier extraction and transport efficiency, thereby further benefiting the photoelectric conversion efficiency of the device.

[0068] In some embodiments, the roughness of the perovskite light-absorbing layer is from 10 nm to 50 nm. Therefore, the perovskite light-absorbing layer of this disclosure has high flatness, indicating improved interfacial contact quality, thereby reducing non-radiative recombination at the interface and contributing to increased open-circuit voltage of the battery. Exemplarily, the roughness of the perovskite light-absorbing layer grains is 50 nm, 40 nm, 35 nm, 30 nm, 28 nm, 20 nm, 15 nm, 10 nm, etc., but is not limited thereto.

[0069] In some embodiments, the perovskite light-absorbing layer includes thiocyanate ions. By including thiocyanate ions, which are present within the perovskite bulk phase, they passivate halogen vacancies and also passivate excess cations through ionic bonding, thereby further reducing surface defects and thus improving the photoelectric conversion efficiency of the solar cell.

[0070] In this disclosure, the presence of thiocyanate ions in the perovskite light-absorbing layer can be determined, for example, by testing with time-of-flight secondary ion mass spectrometry and XRD, to identify the ions and composition types in the perovskite and thus determine the presence of thiocyanate ions.

[0071] In some embodiments, the perovskite light-absorbing layer further includes Lewis bases containing C=O double bonds and / or C=S double bonds. This allows the lone pair electrons in O and S, and the metal ions in the perovskite, such as Pb ions, to form coordination interactions, further reducing defects and improving the photoelectric conversion efficiency of the device.

[0072] In this disclosure, the term "Lewis base" refers to an electron donor, which is a molecule, ion, or group of atoms that can donate electron pairs in the Lewis acid-base theory.

[0073] Similarly, in this disclosure, Lewis bases containing C=O double bonds and / or C=S double bonds in the perovskite light-absorbing layer can be determined, for example, by time-of-flight secondary ion mass spectrometry and XRD, to identify the presence of such substances.

[0074] In some embodiments, the amount of thiocyanate ions in the perovskite light-absorbing layer is 0.001 mol to 0.006 mol relative to 1 mol of perovskite.

[0075] For example, the amount of thiocyanate ions relative to 1 mol of perovskite is 0.001 mol, 0.002 mol, 0.003 mol, 0.004 mol, 0.005 mol, 0.006 mol, or any two of these values, but is not limited to these. By including thiocyanate ions within this range, it is more beneficial for thiocyanate ions to exert an effective passivation effect, reduce surface defects, and thus improve the photoelectric conversion efficiency of the device.

[0076] In some embodiments, the amount of Lewis bases containing C=O double bonds and / or C=S double bonds in the perovskite light-absorbing layer is 0.001 mol to 0.01 mol relative to 1 mol of perovskite. This allows the lone pair electrons in O and S to effectively coordinate with metal ions in the perovskite, such as Pb ions, reducing defects and further improving the photoelectric conversion efficiency of the device. Exemplarily, the amount of Lewis bases containing C=O double bonds and / or C=S double bonds relative to 1 mol of perovskite is 0.001 mol, 0.002 mol, 0.004 mol, 0.006 mol, 0.008 mol, 0.010 mol, or any range of two such values, but is not limited thereto.

[0077] In this disclosure, thiocyanate ions, Lewis bases containing C=O double bonds, and Lewis bases containing C=S double bonds in the perovskite absorbing layer can be determined using instruments and methods known in the art. For example, the types of ions and components in the perovskite absorbing layer can be tested using time-of-flight secondary ion mass spectrometry (TOF-SIMS) and XRD, thereby determining its composition (perovskite, SCN). - The compound is a Lewis base containing a C=O double bond or a C=S double bond. A portion of the perovskite absorber layer is digested, and the elemental composition of the perovskite can be quantitatively determined using inductively coupled plasma mass spectrometry (ICP-MS). Based on the forms of matter and the amounts of elements present in the perovskite, a system of ternary equations is established to calculate the molar amount of each compound.

[0078] In some embodiments, the solar cell further includes a first electrode and a second electrode, the first electrode having opposite polarities to the second electrode. Thus, the two electrodes with opposite polarities can respectively transport electrons and holes generated in the perovskite light-absorbing layer to the outside to form a circuit.

[0079] The perovskite solar cell of this disclosure will be further described below with reference to the accompanying drawings.

[0080] Figure 1 shows a schematic diagram of the structure of a perovskite solar cell according to an embodiment of the present disclosure. The perovskite solar cell 10 includes: a first electrode 11, a perovskite light-absorbing layer 13, and a second electrode 12, wherein the first electrode 11 and the second electrode 12 have opposite polarities.

[0081] In some embodiments, the first electrode 11 is used to collect holes, serving as the negative electrode of the solar cell, and the second electrode 12 is used to collect electrons, serving as the positive electrode of the solar cell. In other embodiments, the first electrode 11 is used to collect electrons, serving as the positive electrode of the solar cell, and the second electrode 12 is used to collect holes, serving as the negative electrode of the solar cell. In some embodiments, one of the first and second electrodes is a transparent electrode. This transparent electrode is the electrode that first receives incident light. Exemplarily, the transparent electrode may include a transparent conductive material. This disclosure does not particularly limit the transparent conductive material. Exemplarily, transparent conductive materials include one or more of the following: tin oxide, indium tin oxide (ITO), fluorine-doped tin oxide (FTO), indium-doped zinc oxide (IZO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide, antimony-doped tin oxide, indium-doped tungsten oxide (IWO), indium-doped chromium oxide (ICrO), indium-doped titanium oxide (ITiO), and graphene.

[0082] In some embodiments, the other electrode of the first and second electrodes may include the transparent conductive material described above or other conductive materials. This disclosure does not particularly limit the use of other conductive materials. For example, other conductive materials include one or more of metals and their alloys, and elemental carbon materials. Exemplarily, metals and their alloys include one or more of gold, silver, copper, aluminum, nickel, chromium, bismuth, platinum, magnesium, molybdenum, and tungsten. Exemplarily, elemental carbon materials include one or more of graphite, graphene, and carbon nanotubes. Exemplarily, organic conductive materials include at least one of poly(3,4-ethylenedioxythiophene), polythiophene, and polyacetylene.

[0083] In some embodiments, when the first electrode 11 is a transparent electrode that first receives incident light and is used to collect holes, the resulting perovskite cell is an inverted perovskite solar cell (pin). In other embodiments, when the second electrode 12 is a transparent electrode that first receives incident light and is used to collect electrons, the resulting perovskite cell is a conventional perovskite solar cell (nip).

[0084] In some embodiments, the first electrode is a transparent electrode, or also referred to as the front electrode; the second electrode is an electrode formed of other conductive materials as described above, or also referred to as the back electrode.

[0085] In some embodiments, the thicknesses of the first electrode 11 and the second electrode 12 are in the range of 10 nm to 1000 nm, respectively.

[0086] The perovskite light-absorbing layer 13 comprises a perovskite material. In some embodiments, the perovskite material comprises at least one of the perovskite compounds shown in [A][B][X]3 and [A]2[C][D][X]6, wherein A comprises at least one inorganic or organic monovalent cation, B comprises at least one inorganic divalent cation, C comprises at least one inorganic monovalent cation, D comprises at least one inorganic trivalent cation, and X comprises at least one monovalent anion.

[0087] For example, organic monovalent cations include (NR1R2R3R4). + (R1R2N=CR3R4) + (R1R2N-C(R5)=NR3R4) + Or (R1R2N-C(NR5R6)=NR3R4) + One or more of the following, wherein R1, R2, R3, R4, R5, and R6 are each independently selected from H, substituted or unsubstituted C1-C20 alkyl groups, or substituted or unsubstituted aryl groups. Optionally, the organic monovalent cation includes (H2N=CH-NH2). + (abbreviated as FA), CH3NH3 + One or more of (abbreviated as MA).

[0088] For example, the inorganic monovalent cation includes: Li + Na + K + 、Rb + Cs + Cu + Ag + Au + or Hg + At least one of them.

[0089] For example, the inorganic divalent cation includes: Pb 2+ Sn 2+ Be 2+ Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ Zn 2+ 、Ge 2+ Fe 2+ Co 2+ Ni 2+ Cd 2+ Cu 2+ Mn 2+ Pd 2+ Yb 2+ Or Eu 2+ At least one of them.

[0090] For example, inorganic trivalent cations include: Bi 3+ Sb 3+ Cr 3+ Fe 3+ Co 3+ Ga 3+ As 3+ Ru 3+ ,Rh 3+ In 3+ Ir 3+ Au 3+ Or Al 3+ At least one of them.

[0091] For example, monovalent anions include: F - Cl - ,Br - I - SCN - CNO - OCN - OSCN - SH - CN - SeCN - At least one of them.

[0092] In some embodiments, the perovskite light-absorbing layer comprises a perovskite compound represented by formula (I).

[0093] [A][B][X]3 (I),

[0094] A includes FA, MA, and Cs. + At least one of them, B is Sn 2+ and / or Pb 2+ X includes Cl - ,Br - I - At least two of them, FA represents (H2N=CH-NH2). + MA represents CH3NH3 +

[0095] In some embodiments, the perovskite light-absorbing layer includes FA. 0.8 Cs 0.2 Pb(I 0.4 Br 0.6 3.

[0096] In some embodiments, the perovskite solar cell 10 further includes a hole transport layer 151 and an electron transport layer 152, wherein the hole transport layer 151 is located between the first electrode 11 and the perovskite light-absorbing layer 13, and the electron transport layer 152 is located between the perovskite light-absorbing layer 13 and the second electrode 12. Thus, the arrangement of the hole transport layer and the electron transport layer facilitates the extraction and transport of holes and electrons generated by the perovskite light-absorbing layer to the first electrode and the second electrode, respectively, forming a loop via an external circuit, which can be used to drive a load.

[0097] Those skilled in the art will understand that FIG1 is merely an exemplary illustration of a hole transport layer 151 disposed on the side surface of the perovskite light-absorbing layer 13 facing the first electrode 11, and the above example does not constitute a specific limitation. In some embodiments, the hole transport layer 151 may also be disposed on the side surface of the perovskite light-absorbing layer 13 facing the second electrode 12.

[0098] In this disclosure, the hole transport layer has the function of extracting and transporting holes, which is used to transport the holes generated by the excitation of the perovskite light-absorbing layer to the adjacent electrode and block the transport of electrons.

[0099] This disclosure does not impose any particular limitation on the hole transport material used in the hole transport layer; hole transport materials commonly used in the art can be used. For example, the hole transport material includes: nickel oxide (NiO). x , 1≤x≤2), cuprous iodide (CuI), cuprous oxide (Cu2O), cuprous thiocyanate (CuSCN), 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), 2,2',7,7'-tetratetra(di-p-tolylamino)spiro-9,9'-difluorene (Spiro-TTB), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), and [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz), (4-(3,6-dimethyl ... (4-(9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz), (4-(3,6-dibromo-9H-carbazole-9-yl)butyl)phosphonic acid (Br-4PACz), (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (MeO-2PACz), (2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl)phosphonic acid (Me-2PACz), (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz), (2-(3,6-dibromo-9H-carbazole-9-yl)ethyl)phosphonic acid (Br-2PACz), etc.

[0100] This disclosure does not impose any particular limitation on the thickness of the hole transport layer; any thickness conventionally used in the art for hole transport layers may be adopted. For example, the thickness of the hole transport layer is 1 nm to 200 nm.

[0101] In this disclosure, the electron transport layer has the function of transporting electrons, which is used to extract and transport electrons generated by the excitation of the perovskite light-absorbing layer 13 to the adjacent electrode, and to prevent the transport of holes.

[0102] This disclosure does not impose any particular limitation on the electron transport material used in the electron transport layer; commonly used electron transport materials in the art can be used. For example, electron transport materials include at least one of the following: imide compounds, quinone compounds, fullerenes and their derivatives, metal oxides, semiconductor oxides, titanates, fluorides and their derivatives, and materials obtained by doping or passivation. Exemplarily, imide compounds include at least one of: phthalimide, succinimide, N-bromosuccinimide, glutarimide, or maleimide. Exemplarily, quinone compounds include at least one of: benzoquinone, naphthoquinone, phenanthrenequinone, or anthraquinone. Exemplarily, the metal element in the metal oxide includes at least one of: Mg, Cd, Zn, In, Pb, W, Sb, Bi, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, or Cr. Exemplarily, fullerenes and their derivatives include fullerene C. 60 Fullerene C 70 [6,6]-based C 61 methyl butyrate (PC) 61 BM), [6,6]-based C 71 methyl butyrate (PC) 71 One or more of the following: BM (metal oxide). Optionally, the metal oxide includes at least one of tin dioxide (SnO2) and titanium dioxide (TiO2). Exemplarily, the semiconductor material oxide includes silicon oxide. Exemplarily, the titanate includes at least one of strontium titanate and calcium titanate. Exemplarily, the fluoride includes at least one of lithium fluoride and calcium fluoride.

[0103] This disclosure does not impose any particular limitation on the thickness of the electron transport layer; any thickness conventionally used in the art for electron transport layers may be adopted. For example, the thickness of the electron transport layer is 5 nm to 100 nm.

[0104] In some embodiments, the electron transport layer material includes at least one of the following materials and their derivatives, as well as materials obtained by doping or passivation: [6,6]-phenylC 61 Methyl butyrate (PC) 61 BM), [6,6]-phenyl C 71 Methyl butyrate (PC) 71 BM), Fullerene C 60 Fullerene C70 Materials include indene-C60 diadduct (ICBA), tin dioxide, zinc oxide (ZnO), perylene imide (PDI) materials, and naphthalene imide (NDI) materials. For example, the electron transport layer thickness is 15 nm to 30 nm.

[0105] In some embodiments, the perovskite solar cell includes a hole-blocking layer disposed between the electron transport layer and the second electrode. The hole-blocking layer improves both electron extraction and hole blocking performance.

[0106] The hole blocking layer includes a hole blocking material. This disclosure does not specifically limit the hole blocking material; by way of example, the hole blocking material may include one or more of SnO2 and copper bath (BCP, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline).

[0107] This disclosure does not impose any particular limitation on the thickness of the hole blocking layer; any thickness conventionally used in the art for hole blocking layers may be adopted. For example, the thickness of the hole blocking layer is from 0.5 nm to 20 nm.

[0108] In some embodiments, the perovskite solar cell further includes a passivation layer disposed on at least one surface of the perovskite light-absorbing layer, which helps to reduce defects at the interface and further improve the performance of the perovskite solar cell.

[0109] The passivation layer may include passivating agents conventionally used in the art for passivating perovskite light-absorbing layers, such as small organic molecules, organic salts, inorganic salts, and polymers. Small organic molecule passivating agents include, but are not limited to, phenylethylamine, ethylenediamine, pyridine, butanethiol, and 2,5-thiophene dicarboxylic acid. Organic salt passivating materials include, but are not limited to, piperazine iodine, phenylethylamine hydroiodate, dodecyl hydroiodate, guanidine bromide, thiophene ethylamine hydroiodate, ethylenediamine hydroiodate, and oleylamine iodine. Inorganic salt passivating materials include, but are not limited to, zinc chloride, potassium chloride, and gallium chloride. Polymer passivating materials include, but are not limited to, polymethyl methacrylate, polyethylene oxide, polyacrylonitrile, and polyvinyl alcohol.

[0110] In some embodiments, a perovskite solar cell includes a first electrode, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a second electrode stacked sequentially. The first electrode is a transparent electrode used to initially receive incident light. This results in an inverted perovskite solar cell, where the hole transport layer can be better matched to the transparent electrode, reducing charge recombination losses at the interface and further improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0111] In some embodiments, the perovskite solar cell further includes a substrate layer disposed on the side of the first electrode away from the hole transport layer for supporting the perovskite solar cell. The substrate layer can be, but is not limited to, a glass substrate or a flexible substrate. In some embodiments, the flexible substrate layer may be made of, for example (but not limited to), an organic polymer material, and further, may be a mixture of one or more of the following materials in different proportions: including but not limited to polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), polydimethylsiloxane (PDMS), etc.

[0112] Methods for preparing solar cells

[0113] This disclosure also provides a method for fabricating a solar cell, including the preparation of a perovskite light-absorbing layer. The preparation of the perovskite light-absorbing layer includes: preparing a perovskite precursor solution, wherein the perovskite precursor solution comprises a perovskite precursor compound, a thiocyanate ion, and a Lewis base containing a C=O bond and / or a Lewis base containing a C=S bond; and growing the perovskite precursor solution into perovskite grains, followed by annealing.

[0114] In this disclosure, thiocyanate and Lewis bases containing C=O or C=S bonds are added during the preparation of the perovskite light-absorbing layer. These Lewis bases coordinate with ions in the perovskite precursor to form an intermediate phase, slowing down the perovskite crystallization rate. Simultaneously, thiocyanate reacts in the perovskite system to produce HSCN gas, which promotes grain boundary dissolution, causing small grains to fuse and grow larger, thereby further increasing the grain size and achieving an atmospheric annealing effect. Therefore, by adding these two types of substances during the preparation process, the perovskite grain size can be increased.

[0115] In some embodiments, the amount of thiocyanate in the perovskite precursor solution is 0.005 mol to 0.05 mol relative to 1 mol of perovskite precursor. This facilitates the creation of an effective HSCN gas atmosphere for the crystallization process, dissolving grain boundaries, causing small grains to fuse and grow larger, while also allowing some to remain in the bulk phase, further contributing to passivation. Exemplarily, the amount of thiocyanate relative to 1 mol of perovskite precursor may be 0.005 mol, 0.007 mol, 0.010 mol, 0.020 mol, 0.03 mol, 0.04 mol, 0.045 mol, 0.05 mol, or any value within a range of two such values, but is not limited thereto.

[0116] The term "perovskite precursor compounds" refers to all compounds that react to form perovskite. For example, when CsBr, CsI, FABr, FAI, PbBr2, and PbI2 are used to form perovskite grains, the term "perovskite precursor compounds" refers to all of these compounds.

[0117] In some embodiments, in the perovskite precursor solution, the amount of Lewis bases containing C=O bonds and / or Lewis bases containing C=S bonds is 0.01 mol to 0.1 mol relative to 1 mol of perovskite precursor compound. This effectively exerts coordination, slows down perovskite crystallization, and promotes grain size increase. Exemplarily, the amount of Lewis bases containing C=O bonds and / or Lewis bases containing C=S bonds relative to 1 mol of perovskite precursor compound is 0.01 mol, 0.02 mol, 0.03 mol, 0.04 mol, 0.05 mol, 0.06 mol, 0.07 mol, 0.08 mol, 0.09 mol, 0.1 mol, or any value within a range of two such values, but is not limited thereto.

[0118] In some embodiments, the molar ratio of thiocyanate to a Lewis base containing C=O bonds and / or a Lewis base containing C=S bonds in the perovskite precursor solution is 1:(1 to 4). This further facilitates slowing down the crystallization of perovskite and increasing the grain size. Exemplarily, the molar ratio of thiocyanate to a Lewis base containing C=O bonds and / or a Lewis base containing C=S bonds is 1:1, 1:1.5, 1:2, 1:3, 1:4, or any range of two such values, but is not limited thereto. Exemplarily, the molar ratio of thiocyanate to a Lewis base containing C=O bonds and / or a Lewis base containing C=S bonds is 1:1.6.

[0119] In some embodiments, Lewis bases containing C=O bonds include one or more amino groups, such as one or two amino groups. In some embodiments, Lewis bases containing C=S bonds include one or more amino groups, such as one or two amino groups.

[0120] In some embodiments, the Lewis base containing a C=O bond includes one or more of urea, 1,1-dimethylurea, 1,3-dimethylurea, ethylurea, or (hydroxymethyl)urea. In some embodiments, the Lewis base containing a C=S bond includes one or more of thiourea, N-methylthiourea, or trimethylthiourea.

[0121] In some embodiments, the compounds providing the thiocyanate ion include one or more of ammonium thiocyanate (NH4SCN), guanidine thiocyanate (GuaSCN), formamidinium thiocyanate (FASCN), methylamine thiocyanate (MASCN), cesium thiocyanate (CsSCN), potassium thiocyanate (KSCN), cuprous thiocyanate (CuSCN), and lead thiocyanate (Pb(SCN)2).

[0122] In some embodiments, the annealing temperature is between 50°C and 80°C. Annealing temperatures within this range help maintain the residual amount of thiocyanate in the system within an appropriate range, allowing the residual thiocyanate ions to passivate halogen vacancies, reduce surface defects, and thus improve photoelectric conversion efficiency.

[0123] In some embodiments, the annealing time is 3–10 min. Annealing time within this range helps maintain the residual amount of thiocyanate in the system within an appropriate range, thus passivating halogen vacancies. Optionally, the annealing time is 5–7 min.

[0124] Furthermore, there are no particular limitations on the preparation methods of the various functional layers of the solar cell, such as the first electrode, metal oxide layer, self-assembled monolayer, passivation layer, electron transport layer, hole blocking layer, and second electrode. These methods can include those conventionally used in the art, such as chemical bath deposition, electrochemical deposition, chemical vapor deposition, physical epitaxial growth, vacuum thermal evaporation, atomic layer deposition, magnetron sputtering, spin coating, slot coating, blade coating, and mechanical pressing.

[0125] photovoltaic modules

[0126] This disclosure also provides a photovoltaic module, including the solar cell provided in the above embodiments or the solar cell obtained according to the method provided in the above embodiments. In some embodiments, the photovoltaic module further includes solder strips connecting multiple solar cells, a junction box for current transmission, and a cell encapsulation component.

[0127] In some embodiments, the battery encapsulation component includes photovoltaic glass. The photovoltaic glass covers the aforementioned solar cell, serving to protect it. Simultaneously, the photovoltaic glass possesses excellent light transmittance and high hardness, allowing it to withstand large diurnal temperature variations and harsh weather conditions.

[0128] In some embodiments, the battery encapsulation component includes an ethylene-vinyl acetate copolymer (EVA) film disposed between the photovoltaic glass and the solar cell for bonding the photovoltaic glass and the solar cell.

[0129] In some implementations, the battery encapsulation components include a photovoltaic backsheet. The photovoltaic backsheet serves to protect the solar cells.

[0130] Optionally, the photovoltaic backsheet material may include a polyvinyl fluoride composite film or a thermoplastic elastic material. The photovoltaic backsheet material possesses properties such as insulation, water resistance, and aging resistance.

[0131] In some implementations, the battery encapsulation component includes a solar aluminum frame, made of aluminum alloy, which features high strength and corrosion resistance. It serves to support and protect the solar cells.

[0132] Power generation unit

[0133] This disclosure also provides a power generation device, including the solar cell provided in the above embodiments or the solar cell obtained according to the method provided in the above embodiments.

[0134] Electrical appliances

[0135] This disclosure also provides an electrical device, including the solar cell provided in the above embodiments or the solar cell obtained according to the method provided in the above embodiments.

[0136] In some implementations, the electrical appliances include lighting equipment, energy storage equipment, etc., but are not limited to these. For example, electrical appliances include solar water heaters, solar streetlights, solar photovoltaic generators, etc.

[0137] Example

[0138] The following describes embodiments of this disclosure. The embodiments described below are exemplary and are only used to explain this disclosure, and should not be construed as limiting this disclosure. 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 the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0139] Example 1

[0140] 1. Provide the first electrode

[0141] A 2.0×2.0cm FTO conductive glass substrate (i.e., fluorine-doped SnO2 transparent metal oxide) was taken, and 0.35cm of FTO was removed from both ends by laser etching to expose the glass substrate. The substrate was then cleaned sequentially with an aqueous solution containing detergent, deionized water, and ethanol. After drying the cleaned substrate under a nitrogen gun, it was irradiated in a UV ozone generator for 20 minutes and set aside for later use.

[0142] 2. Preparation of the hole transport layer

[0143] An ethanol solution of 80 μL of MeO-4PACz (0.3 mg / mL) was dropped onto an FTO conductive glass substrate, spin-coated at 4000 rpm for 30 seconds, and annealed at 100 °C for 10 minutes to obtain a hole transport layer with a thickness of 10 nm.

[0144] 3. Preparation of the perovskite light-absorbing layer

[0145] Preparation of perovskite light-absorbing layer

[0146] 0.05 mmol CO(NH2)2, 0.0155 mmol Pb(SCN)2, 0.08 mmol CsBr, 0.12 mmol CsI, 0.32 mmol FABr, 0.48 mmol FAI, 0.4 mmol PbBr2, and 0.6 mmol PbI2 were dissolved in 1 mL of a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) (DMF to DMSO volume ratio 4:1) and stirred for 2 hours. The solution was filtered through a 0.22 μm organic filter membrane to obtain the perovskite precursor solution. Relative to 1 mol of perovskite precursor (0.08 mmol CsBr, 0.12 mmol CsI, 0.32 mmol FABr, 0.48 mmol FAI, 0.4 mmol PbBr2, and 0.6 mmol PbI2, totaling 2 mmol), SCN... - The content is 0.0155 mol, and the content of Lewis bases containing C=O bonds is 0.025 mol.

[0147] Under a nitrogen atmosphere, 95 μL of perovskite precursor liquid was dropwise added to the hole transport layer, and spin-coated at 5000 rpm for 25 seconds. Then, it was placed in a vacuum flash evaporator for 30 seconds and annealed on an 80°C hot plate for 3 minutes to obtain a FA layer with a thickness of 450 nm. 0.8 Cs 0.2 Pb(I 0.4 Br 0.6 )3 Perovskite light-absorbing layer.

[0148] 4. Fabrication of electron transport layer, hole blocking layer, and second electrode

[0149] On the perovskite layer, a 25 nm fullerene (C60) layer is formed sequentially by vapor deposition using a vapor deposition machine as an electron transport layer, an 8 nm 2,9-dimethyl-4,7-biphenyl-1,10-o-diazaphenanthroline (BCP) layer as a hole blocking layer, and a 100 nm electrode Cu layer as a second electrode.

[0150] Thus, perovskite solar cells were obtained.

[0151] Example 2

[0152] The solar cell was prepared using a method similar to that in Example 1, except that in the preparation of the perovskite light-absorbing layer, 0.05 mmol urea CO(NH2)2 was replaced with 0.05 mmol thiourea CS(NH2)2.

[0153] Example 3

[0154] The solar cell was prepared in a similar manner to that in Example 1, except that in the preparation of the perovskite light-absorbing layer, 0.32 mmol FABr and 0.48 mmol FAI were replaced with 0.32 mmol MABr and 0.48 mmol MAI.

[0155] Example 4

[0156] Solar cells were prepared using a method similar to that in Example 1, except that 0.0155 mmol Pb(SCN)2 was replaced with 0.031 mmol NH4SCN in the preparation of the perovskite light-absorbing layer.

[0157] Example 5

[0158] Solar cells were prepared using a method similar to that in Example 1, except that 0.0155 mmol Pb(SCN)2 was replaced with 0.031 mmol guanidine thiocyanate in the preparation of the perovskite light-absorbing layer.

[0159] Example 6

[0160] Solar cells were prepared using a method similar to that in Example 1, except that 0.0155 mmol Pb(SCN)2 was replaced with 0.031 mmol CuSCN in the preparation of the perovskite light-absorbing layer.

[0161] Example 7

[0162] Solar cells were prepared using a method similar to that in Example 1, except that 0.0155 mmol Pb(SCN)2 was replaced with 0.031 mmol MASCN in the preparation of the perovskite light-absorbing layer.

[0163] Example 8

[0164] The solar cell was prepared using a method similar to that in Example 1, except that in the preparation of the perovskite light-absorbing layer, 0.05 mmol of urea CO(NH2)2 was replaced with 0.05 mmol of N-methylthiourea.

[0165] Example 9

[0166] The solar cell was prepared using a method similar to that in Example 1, except that in the preparation of the perovskite light-absorbing layer, 0.05 mmol of urea CO(NH2)2 was replaced with 0.05 mmol of 1,1-dimethylurea.

[0167] Example 10

[0168] The solar cell was prepared using a method similar to that in Example 1, except that in the preparation of the perovskite light-absorbing layer, 0.05 mmol of urea CO(NH2)2 was replaced with 0.05 mmol of 1,3-dimethylurea.

[0169] Comparative Example 1

[0170] The solar cell was prepared using the same method as in Example 1, except that 0.05 mmol CO(NH2)2 and 0.0155 mmol Pb(SCN)2 were not added during the preparation of the perovskite light-absorbing layer.

[0171] Comparative Example 2

[0172] The solar cell was prepared using the same method as in Example 1, except that 0.05 mmol CO(NH2)2 was not added during the preparation of the perovskite light-absorbing layer.

[0173] Comparative Example 3

[0174] Solar cells were prepared using the same method as in Example 1, except that 0.0155 mmol Pb(SCN)2 was not added during the preparation of the perovskite light-absorbing layer.

[0175] Comparative Example 4

[0176] The solar cell was prepared using the same method as in Example 3, except that 0.05 mmol CO(NH2)2 and 0.0155 mmol Pb(SCN)2 were not added during the preparation of the perovskite light-absorbing layer.

[0177] Characterization of the perovskite light-absorbing layer

[0178] After the perovskite light-absorbing layer was prepared, the perovskite layer was characterized as follows.

[0179] SEM morphology characterization

[0180] The morphology of the perovskite light-absorbing layer was measured using a JEOL JSM-IT200 high-throughput scanning electron microscope (SEM). The SEM test conditions were: backscatter detector mode, voltage 3KV, and working distance 5mm.

[0181] Figure 2 shows scanning electron microscope images of the perovskite light-absorbing layer of Comparative Example 1, Comparative Example 2, Comparative Example 3, and Example 1.

[0182] As shown in Figure 2, compared to Comparative Example 1 without additives and with SCN, - Or, in comparative examples 2 and 3 of urea, SCN was simultaneously added to Example 1 of this disclosure. - With urea, the perovskite grain size increases significantly.

[0183] Average grain size (S)

[0184] 1. Sample preparation:

[0185] o Place the perovskite layer to be tested on a clean surface.

[0186] o Clean the surface of the perovskite layer using a dry nitrogen gun.

[0187] o Secure the cleaned perovskite layer sample onto the sample holder, ensuring the sample surface is flat and in good contact with the holder.

[0188] 2. SEM sample clamping:

[0189] o Use conductive tape to fix the sample holder to the SEM sample stage.

[0190] o The perovskite layer sample maintains good contact with the sample stage.

[0191] 3. SEM parameter settings:

[0192] o Set the acceleration voltage according to the SEM equipment's operation manual.

[0193] o Set the working distance (WD) and magnification to obtain a clear image of the grain morphology.

[0194] o Adjust the beam current to obtain the best image resolution and signal-to-noise ratio.

[0195] 4. SEM imaging:

[0196] o Image the sample in SEM to obtain SEM images of the perovskite film surface.

[0197] o Ensure the image contains a sufficient number of grains for statistical analysis.

[0198] 5. Grain size measurement:

[0199] o Use SEM software tools or image analysis software to measure the longest size of the grains in the image.

[0200] o Record the size data of 100 grains to ensure the reliability of the statistical results.

[0201] 6. Data Processing:

[0202] Calculate the average of all measured grain sizes, and denote it as the average grain size of the perovskite layer.

[0203] Use the automatic measurement function of image analysis software to speed up this process.

[0204] Cross-sectional morphology

[0205] The perovskite light-absorbing layer was sectioned using a glass cutter, and the cross-section of the section was scanned using the aforementioned SEM.

[0206] Figure 3 shows scanning electron microscope images of cross sections of the perovskite light-absorbing layer of Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 1.

[0207] In each sub-figure of Figure 3, the lower layer with cracks is the FTO conductive glass substrate, and the upper layer is the perovskite light-absorbing layer. Example 1 shows a significant improvement in grain size and surface smoothness.

[0208] Surface photovoltage measurement (SPV)

[0209] The contact potential (CPD) between the AFM tip and the perovskite absorber sample was measured using a Kelvin probe force microscope (KPFM) of Bruker Dimension icon XR, Germany, under both dark and 430 nm laser illumination. The difference between the CPD under dark and illuminated conditions is called the surface photovoltage (SPV), where SPV = CPD. 光照 -CPD 黑暗 .

[0210] Surface roughness (Ra)

[0211] 1. Data Acquisition: The height data of the perovskite light-absorbing layer sample under test was acquired using atomic force microscopy (AFM).

[0212] 2. Data processing: Convert the acquired height data into a three-dimensional surface model.

[0213] 3. Calculate the average height: Calculate the average height Z of all points within the measurement area. mean .

[0214] 4. Calculate height deviation: For each point within the measurement area, calculate the absolute value of the deviation between its height and the average height, |Z|. (x,y) -Z mean |

[0215] 5. Calculate the sum of absolute deviations: Add the absolute values ​​of the height deviations of all points to get the sum.

[0216] 6. Calculate the average value: Divide the sum by the area of ​​the measurement area to obtain the surface roughness (Ra value).

[0217] Residual thiocyanate ions (SCN) - Determination of Lewis bases containing C=O double bonds and Lewis bases containing C=S double bonds

[0218] Qualitative analysis: Time-of-flight secondary ion mass spectrometry (TOF-SIMS) and XRD can be used to test the ion and component types in the perovskite absorbing layer, thereby determining its composition. In Example 1, the molecular structure of the compound was obtained by TOF-SIMS and XRD testing; A, FA 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 )3; B, Pb(SCN)2, C, CO(NH2)2.

[0219] Quantitative analysis: A portion of the perovskite light-absorbing layer was digested, and the content of each element in the perovskite film was quantitatively determined by inductively coupled plasma mass spectrometry (ICP-MS). After digesting the perovskite light-absorbing layer in Example 1, 715 mg was injected, and the results are shown in Table 1 below.

[0220] Table 1

[0221] The amount of Cs, I, and Br can be used to calculate FA. 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 The amount of substance of 3 is 1.2 mmol, and Pb(SCN)2 is calculated based on the amount of Pb. At the same time, the amount of substance of Pb(SCN)2 can also be obtained from the amount of S, which is 0.0037 mmol. Based on the amount of substance of O or the remaining H, the amount of substance of CO(NH2)2 is 0.0062 mmol. Thus, the amount of additive contained in each mol of perovskite can be obtained.

[0222] The amounts of thiocyanate ions and Lewis bonds containing C=O bonds and / or Lewis bases containing C=S bonds in the perovskite light-absorbing layers of Examples 1-10 and Comparative Examples 1-4, relative to 1 mol of perovskite, are shown in Table 2 below.

[0223] Based on the above results, compared with Comparative Examples 1 and 4 without additives, or Comparative Examples 2 and 3 with only one type of additive, the grain size, surface photovoltage, and roughness of the perovskite light-absorbing layers in Examples 1 to 10 are significantly improved.

[0224] Testing the photoelectric performance of solar cells

[0225] Open circuit voltage (V) at room temperature (25℃) OC ), short-circuit current density (J SC The test methods for fill factor (FF) and initial photoelectric conversion efficiency are as follows.

[0226] Following the national standard IEC61215, using Guangyan's solar simulator, the light intensity of crystalline silicon solar cells was corrected to achieve 1 solar intensity, AM 1.5. The solar cells underwent reverse scanning testing using a Keithley 2400 source meter, and the Vo was measured. OC J SC And FF, and calculate the initial photoelectric conversion efficiency (PCE) of the solar cell using the following formula:

[0227] Among them, P input This represents the incident light power density.

[0228] The performance test results of the solar cells of Examples 1 to 10 and Comparative Examples 1 to 4 are shown in Table 3 below.

[0229] Table 3

[0230] Based on the above results, it can be seen that the solar cell of this embodiment significantly improves the open-circuit voltage V. OC And photoelectric conversion efficiency.

[0231] Examples 11-16

[0232] Solar cells were prepared using the same method as in Example 1, except that the annealing temperature and time of the perovskite light-absorbing layer preparation process were adjusted in Examples 11-16.

[0233] The characterization results of the perovskite light-absorbing layers in Examples 1, 11-16 are shown in Table 4 below, and the performance test results of the solar cells are shown in Table 5 below.

[0234] Table 4

[0235] Table 5

[0236] Based on the above results, it can be seen that by annealing at a temperature of 50℃ to 80℃ and an annealing time of 3 to 10 minutes, the resulting perovskite light-absorbing layer enables the corresponding device to have improved open-circuit voltage and photoelectric conversion efficiency.

[0237] It should be noted that this disclosure is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same essential structure and achieving the same effect as the technical concept within the scope of this disclosure are included in the technical scope of this disclosure. 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, are also included in the scope of this disclosure without departing from the spirit of this disclosure.

Claims

1. A solar cell, said solar cell comprising a perovskite light-absorbing layer; in, The average grain size of the perovskite grains in the perovskite light-absorbing layer is 500 nm to 1500 nm, and the surface photovoltage of the perovskite light-absorbing layer, measured by Kelvin probe force microscopy, is greater than or equal to 0 mV and less than or equal to 60 mV.

2. The solar cell according to claim 1, wherein, The average grain size of the perovskite grains is 500 nm to 1000 nm.

3. The solar cell according to claim 1 or 2, wherein, The surface photovoltage is 10mV to 22mV.

4. The solar cell according to any one of claims 1 to 3, wherein, The roughness of the perovskite light-absorbing layer is 10 nm to 50 nm.

5. The solar cell according to any one of claims 1 to 4, wherein, The perovskite light-absorbing layer includes thiocyanate ions.

6. The solar cell according to claim 5, wherein, The perovskite light-absorbing layer also includes Lewis bases containing C=O double bonds and / or Lewis bases containing C=S double bonds.

7. The solar cell according to claim 5 or 6, wherein, In the perovskite light-absorbing layer, the amount of thiocyanate ions is 0.001 mol to 0.006 mol relative to 1 mol of perovskite.

8. The solar cell according to claim 6, wherein, In the perovskite light-absorbing layer, the amount of Lewis bases containing C=O double bonds and / or Lewis bases containing C=S double bonds is 0.001 mol to 0.01 mol relative to 1 mol of perovskite.

9. The solar cell according to any one of claims 1 to 8, wherein, The perovskite light-absorbing layer comprises at least one of the compounds shown in formula (I) and formula (II): [A][B][X]3 (I), [A]2[C][D][X]6 (II); Wherein, A includes at least one of inorganic or organic monovalent cations, B includes at least one of inorganic or organic divalent cations, C includes at least one of inorganic or organic monovalent cations, D includes at least one of inorganic or organic trivalent cations, and X includes at least one of inorganic or organic monovalent anions.

10. The solar cell according to any one of claims 1 to 9, wherein, The perovskite light-absorbing layer comprises the compound shown in formula (I). [A][B][X]3 (I), A includes FA, MA, and Cs. + At least one of them, B is Sn 2+ and / or Pb 2+ X includes Cl - ,Br - I - At least two of them, FA represents (H2N=CH-NH2). + MA represents CH3NH3 + .

11. The solar cell according to any one of claims 1 to 10, wherein, The solar cell meets one or more of the following conditions: (1) The solar cell further includes a first electrode and a second electrode, wherein the polarities of the first electrode and the second electrode are opposite; (2) The solar cell further includes a first electrode, a hole transport layer, the perovskite light-absorbing layer, an electron transport layer and a second electrode stacked in sequence.

12. A method for fabricating a solar cell, comprising fabricating a perovskite light-absorbing layer, wherein fabricating the perovskite light-absorbing layer comprises: A perovskite precursor solution is prepared, wherein the perovskite precursor solution comprises a perovskite precursor compound, a thiocyanate ion, and a Lewis base containing a C=O bond and / or a Lewis base containing a C=S bond; and The perovskite precursor solution is grown into perovskite grains and then annealed.

13. The preparation method according to claim 12, wherein, In the perovskite precursor solution, the amount of thiocyanate is 0.005 mol to 0.05 mol relative to 1 mol of perovskite precursor.

14. The preparation method according to claim 12 or 13, wherein, In the perovskite precursor solution, the amount of the Lewis base containing C=O bonds and / or the Lewis base containing C=S bonds is 0.01 mol to 0.1 mol relative to 1 mol of perovskite precursor compound.

15. The preparation method according to any one of claims 12 to 14, wherein, In the perovskite precursor solution, the molar ratio of the thiocyanate ion to the Lewis base containing C=O bonds and / or C=S bonds is 1:(1-4).

16. The preparation method according to any one of claims 12 to 15, wherein, The annealing temperature is 50℃~80℃; and / or the annealing time is 3~10min.

17. The preparation method according to any one of claims 12 to 16, wherein, The compounds providing the thiocyanate ion include one or more of ammonium thiocyanate, guanidine thiocyanate, formamidinium thiocyanate, methylamine thiocyanate, cesium thiocyanate, potassium thiocyanate, cuprous thiocyanate, and lead thiocyanate.

18. The preparation method according to any one of claims 12 to 17, wherein, The Lewis base containing a C=O bond comprises one or more amino groups; and / or, the Lewis base containing a C=S bond comprises one or more amino groups.

19. The preparation method according to any one of claims 12 to 18, wherein, The Lewis base containing a C=O bond includes one or more of urea, 1,1-dimethylurea, 1,3-dimethylurea, ethylurea, or (hydroxymethyl)urea; and / or, the Lewis base containing a C=S bond includes one or more of thiourea, N-methylthiourea, or trimethylthiourea.

20. A photovoltaic module comprising a solar cell according to any one of claims 1 to 11 or a solar cell prepared by any one of claims 12 to 19.

21. A power generation device comprising a solar cell according to any one of claims 1 to 11 or a solar cell prepared by any one of claims 12 to 19.

22. An electrical device comprising a solar cell according to any one of claims 1 to 11 or a solar cell prepared by any one of claims 12 to 19.

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