Solar cell and manufacturing method therefor, photovoltaic module, power generation device, and electric device

Abstract

The present disclosure provides a solar cell. The solar cell comprises a first electrode layer and a metal oxide layer that are stacked, and a self-assembled monolayer, a light absorption layer, and a second electrode layer that are arranged on the metal oxide layer, wherein the hydroxyl index of the surface of the metal oxide layer is 2.5-4.5.

Description

Solar cells and their manufacturing methods, photovoltaic modules, power generation devices and power consumption devices

[0001] Cross-reference to related applications

[0002] This disclosure is based on and claims priority to Chinese Patent Application No. 202510005603.9, filed on January 2, 2025, entitled “Solar Cells and Methods for Preparing Themselves, Photovoltaic Modules, Power Generation Devices and Power Consumption Devices”, 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] With the increasing prominence of global energy shortages and environmental pollution, solar cells, as an ideal renewable energy source, are receiving more and more attention. Solar cells, also known as photovoltaic cells, are devices that convert light energy into electrical energy through the photoelectric effect or photochemical effect.

[0005] However, the poor stability of solar cells in related technologies negatively impacts photoelectric conversion efficiency. These shortcomings continue to restrict their practical application and industrialization. Therefore, improving the stability and photoelectric conversion efficiency of solar cells remains an urgent technical problem to be solved. Summary of the Invention

[0006] 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 has improved stability and photoelectric conversion efficiency.

[0007] To achieve the above objectives, the first aspect of this disclosure provides a solar cell, which includes a first electrode layer and a metal oxide layer stacked together, and a self-assembled monolayer, a light-absorbing layer and a second electrode layer disposed on the metal oxide layer, wherein the hydroxyl index on the surface of the metal oxide layer is 2.5 to 4.5.

[0008] In the solar cell disclosed herein, the hydroxyl index on the surface of the metal oxide layer is 2.5–4.5, containing a large number of hydroxyl groups. These hydroxyl groups can undergo physicochemical interactions with the oxyacid groups in the self-assembled monolayer (SAM) material. This enhances the bonding force between the SAM layer and the metal oxide layer, reduces the risk of the SAM layer detaching as the solar cell ages, and thus improves the stability and photoelectric conversion efficiency of the solar cell.

[0009] In some embodiments, the hydroxyl index on the surface of the metal oxide layer is 3.8 to 4.2. This further improves the stability and photoelectric conversion efficiency of the solar cell.

[0010] In some embodiments, the metal oxide layer includes one or more of nickel oxide, aluminum oxide, tin oxide, molybdenum oxide, cuprous oxide, vanadium oxide, tungsten oxide, and their doped or passivated derivatives. These metal oxides are beneficial for improving the stability of solar cells.

[0011] In some embodiments, the thickness of the metal oxide layer is 5 nm to 20 nm. This is beneficial for forming a dense and continuous film, while also balancing light utilization and the ability of the metal oxide layer to extract holes.

[0012] A second aspect of this disclosure provides a solar cell, which includes a first electrode layer and a self-assembled monolayer, a light-absorbing layer, and a second electrode layer disposed on the first electrode layer, wherein the hydroxyl index on the surface of the first electrode layer is 2.5 to 4.5.

[0013] In the solar cell disclosed herein, the hydroxyl index on the surface of the first electrode layer is 2.5–4.5, containing a large number of hydroxyl groups. These hydroxyl groups can undergo physicochemical interactions with the oxyacid groups in the SAM material. This enhances the bonding force between the SAM layer and the first electrode layer, reduces the risk of the SAM layer detaching as the solar cell ages, and thus improves the stability and photoelectric conversion efficiency of the solar cell.

[0014] In some embodiments, the hydroxyl index on the surface of the first electrode layer is 3.8 to 4.2. This further improves the stability and photoelectric conversion efficiency of the solar cell.

[0015] In some embodiments, the self-assembled monolayer comprises a compound represented by the general formula QLA, wherein Q is selected from one or more of substituted or unsubstituted aniline groups or substituted or unsubstituted nitrogen-containing aromatic heterocyclic groups; L is selected from one or more of substituted or unsubstituted alkylene groups, substituted or unsubstituted alkenyl groups, substituted or unsubstituted heteroalkylene groups, substituted or unsubstituted aromatic groups, or substituted or unsubstituted heteroaromatic groups; and A is selected from oxyacid groups and their salts or esters.

[0016] In some embodiments, the substituents of the substituted aniline group or nitrogen-containing aromatic heterocyclic group include one or more of the following: halogen group, oxyacid group, substituted or unsubstituted C1-C6 alkyl group, substituted or unsubstituted C1-C6 alkoxy group, substituted or unsubstituted six- to thirty-membered aromatic group, and substituted or unsubstituted five- to thirty-membered heteroaromatic group.

[0017] In some embodiments, the substituents of the substituted alkylene, alkenylene, heteroalkylene, aromatic, and heteroaromatic groups include one or more of halogen groups, oxyacid groups, C1-C6 alkyl groups, C1-C6 alkoxy groups, six- to thirty-membered aromatic groups, and five- to thirty-membered heteroaromatic groups.

[0018] In some embodiments, the oxyacid group is selected from one or more of phosphonic acid groups, hypophosphite groups, sulfonic acid groups, carboxylic acid groups, sulfinic acid groups, boric acid groups, or silicate groups.

[0019] In some embodiments, the self-assembled monolayer includes one or more of the following: [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid, (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid, [4-(9H-carbazole-9-yl)butyl]phosphonic acid, (4-(3,6-dibromo-9H-carbazole-9-yl)butyl)phosphonic acid, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, (2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl)phosphonic acid, (2-(9H-carbazole-9-yl)ethyl)phosphonic acid, and (2-(3,6-dibromo-9H-carbazole-9-yl)ethyl)phosphonic acid.

[0020] The aforementioned compounds can self-assemble into a monolayer, which facilitates the efficient extraction of charge carriers from the light-absorbing layer to the metal oxide layer and / or the first electrode layer via charge tunneling, thereby improving the photoelectric performance of solar cells.

[0021] In some embodiments, the first electrode layer is a transparent electrode layer. This forms a reverse solar cell.

[0022] In some embodiments, the transparent electrode layer comprises one or more of conductive oxides or conductive polymers.

[0023] In some embodiments, the conductive oxide includes one or more of tin oxide, indium tin oxide (ITO), indium zinc oxide (IZO), gallium zinc oxide (GZO), fluorine-doped tin oxide (FTO), indium-doped zinc oxide (IZO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), antimony-doped tin oxide, indium-doped tungsten oxide (IWO), indium-doped chromium oxide (ICrO), and indium-doped titanium oxide (ITiO).

[0024] In some embodiments, the conductive polymer includes one or more of poly(3,4-ethylenedioxythiophene) (PEDOT), polythiophene, and polyacetylene.

[0025] The transparent electrode layer comprises the aforementioned conductive oxide and conductive polymer, which facilitates the increase of the hydroxyl index on its surface through an electrolytic reaction. This enhances the adhesion between the SAM layer and the transparent electrode layer, which serves as the first electrode layer.

[0026] In some embodiments, the solar cell further includes an electron transport layer disposed between the light-absorbing layer and the second electrode layer. The electron transport layer has the function of transporting electrons and blocking hole transport, thereby facilitating the efficient extraction and transport of photogenerated electrons.

[0027] In some embodiments, the light-absorbing layer includes a perovskite light-absorbing layer. This is advantageous for obtaining solar cells with high photoelectric conversion efficiency.

[0028] A third aspect of this disclosure provides a method for preparing a solar cell, the method comprising:

[0029] Provide a first electrode layer;

[0030] A metal oxide layer is prepared on the first electrode layer;

[0031] An electrolytic reaction is carried out on a metal oxide layer in an electrolytic cell, which includes an aqueous solution of inorganic salts as an electrolyte, to generate hydroxyl groups on the surface of the metal oxide layer.

[0032] A self-assembled monolayer was prepared on a metal oxide layer after electrolysis.

[0033] Preparation of light-absorbing layers on self-assembled monolayers; and

[0034] A second electrode layer is prepared on the light-absorbing layer.

[0035] A fourth aspect of this disclosure provides a method for preparing a solar cell, wherein the method includes:

[0036] Provide a first electrode layer;

[0037] An electrolytic reaction is carried out on the first electrode layer in an electrolytic cell, the electrolytic cell including an aqueous solution of inorganic salt as an electrolyte, so as to generate hydroxyl groups on the surface of the first electrode layer.

[0038] A self-assembled monolayer was prepared on the first electrode layer after the electrolysis reaction;

[0039] Preparation of light-absorbing layers on self-assembled monolayers; and

[0040] A second electrode layer is prepared on the light-absorbing layer.

[0041] In the method disclosed herein, hydroxyl groups are generated on the surface of the metal oxide layer or the first electrode layer by electrolytic reaction in an electrolytic cell comprising an aqueous solution of inorganic salts as the electrolyte, thereby increasing the hydroxyl index on the surface. These hydroxyl groups can interact with oxyacid groups in the SAM material, thereby enhancing the bonding force between the SAM layer and the metal oxide layer or the first electrode layer, reducing the risk of the SAM layer detaching as the solar cell ages, and thus improving the stability and photoelectric conversion efficiency of the prepared solar cell.

[0042] In some embodiments, the concentration of inorganic salts in the aqueous solution is 15–20 mg / mL. This facilitates the electrolysis reaction to proceed at an appropriate reaction rate, reduces the influence of concentration polarization, and improves reaction efficiency.

[0043] In some embodiments, the electrolysis reaction is carried out at a voltage of 10V to 15V. By carrying out the electrolysis reaction at a voltage within this range, it is beneficial to obtain a suitable hydroxyl generation rate and to protect the performance of the functional layer in which the electrolysis reaction takes place.

[0044] In some embodiments, the electrolysis reaction is carried out for 1.6 min to 18 min. By allowing the electrolysis reaction to proceed within this time range, it is beneficial to form a sufficient amount of hydroxyl groups on the surface of the functional layer on which the electrolysis reaction takes place, and it is also beneficial to save time and improve operational efficiency.

[0045] The fifth aspect of this disclosure provides a photovoltaic module, which includes a solar cell according to the first or second aspect or a solar cell prepared by the methods of the third or fourth aspect.

[0046] The sixth aspect of this disclosure provides a power generation device, which includes a solar cell of the first or second aspect or a solar cell prepared by the method of the third or fourth aspect.

[0047] The seventh aspect of this disclosure provides an electrical device comprising a solar cell according to the first or second aspect, or a solar cell prepared by the methods of the third or fourth aspect.

[0048] The photovoltaic modules, power generation devices, and power consumption devices disclosed herein include the solar cells provided herein, and therefore have at least the same advantages as solar cells. Attached Figure Description

[0049] Figure 1 shows a flowchart of a method for preparing a solar cell according to one embodiment of the present disclosure.

[0050] Figure 2 shows a flowchart of a method for preparing a solar cell according to another embodiment of the present disclosure. Detailed Implementation

[0051] 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.

[0052] The "range" disclosed in this disclosure 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 expected. 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 disclosure, unless otherwise stated, the numerical range "a–b" 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.

[0053] Unless otherwise specified, all embodiments and optional embodiments of this disclosure can be combined to form new technical solutions.

[0054] Unless otherwise specified, all technical features and optional technical features of this disclosure can be combined to form new technical solutions.

[0055] 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.

[0056] Unless otherwise specified, the terminology used in this disclosure has the common meaning as commonly understood by those skilled in the art.

[0057] 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.

[0058] Unless otherwise specified, the terms "providing / setting / preparing on..." or "providing / setting / preparing on..." refer to providing, setting, or preparing a component on another component, with the components either in direct contact or not. The first component may be directly provided, set, or prepared on the second component, or a third component may be present between the first and second components. For example, if the first layer is provided / set / prepared on the second layer, this includes cases where a third layer exists between the first and second layers. The terms "providing / setting / preparing under..." or "providing / setting / preparing under..." have the same meaning.

[0059] The term "alkyl" refers to a branched, straight-chain, or cyclic saturated aliphatic hydrocarbon group having a specified number of carbon atoms, for example, a C1-C20 alkyl group having 1 to 20 carbon atoms. Exemplarily, alkyl groups include, but are not limited to, C1-C20, C1-C18, C1-C16, C1-C14, C1-C12, C1-C10, C1-C8, C1-C6, C1-C4, C1-C3, C1-C2, or C1 alkyl groups. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl.

[0060] The term "alkoxy" refers to an -O-alkyl group. Here, the definition of alkyl is the same as above. Exemplarily, "alkoxy" can include C1-C20 alkoxy groups having 1 to 20 carbon atoms. Exemplarily, alkoxy groups include, but are not limited to, C1-C20, C1-C18, C1-C16, C1-C14, C1-C12, C1-C10, C1-C8, C1-C6, C1-C4, C1-C3, C1-C2, or C1 alkoxy groups. Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, butoxy, cyclopropoxy, cyclobutoxy, cyclopentoxy, and cyclohexyloxy groups.

[0061] The term "alkylene" refers to a branched, straight-chain, or cyclic saturated aliphatic hydrocarbon subunit having a specified number of carbon atoms, for example, a C1-C20 alkylene having 1 to 20 carbon atoms. Exemplarily, alkylene includes C1-C20, C1-C18, C1-C16, C1-C14, C1-C12, C1-C10, C1-C8, C1-C6, C1-C4, C1-C3, C1-C2, or C1 alkylene. Examples of alkylene include, but are not limited to, methylene, ethylene, n-propylene, isopropylene, n-butylene, and tert-butylene.

[0062] The term "alkenyl" refers to a group formed by the loss of two hydrogen atoms from a branched, linear, or cyclic unsaturated olefin, and having a specified number of carbon atoms, for example, a C2-C20 alkenyl group having 2 to 20 carbon atoms. Exemplarily, alkenyl groups include C2-C20, C2-C18, C2-C16, C2-C14, C2-C12, C2-C10, C2-C8, C2-C6, C2-C4, C2-C3, or C2 alkenyl groups.

[0063] The term "heteroalkylene" refers to a saturated aliphatic hydrocarbon subunit containing one or more branched, straight-chain, or cyclic heteroatoms selected from N, O, S, etc., and having a specified number of carbon atoms, for example, a C1-C20 heteroalkylene having 1 to 20 carbon atoms. Exemplarily, heteroalkylene includes C1-C20, C1-C18, C1-C16, C1-C14, C1-C12, C1-C10, C1-C8, C1-C6, C1-C4, C1-C3, C1-C2, or C1 heteroalkylene.

[0064] The term "aromatic group" refers to a group formed by the loss of two hydrogen atoms from an aromatic hydrocarbon, having a specified number of atoms on the ring, such as a six- to thirty-membered aromatic group having 6 to 30 atoms on the ring. "Aromatic group" can include, but is not limited to, six- to thirty-membered aromatic groups, six- to twenty-membered aromatic groups, six- to fifteen-membered aromatic groups, or six- to ten-membered aromatic groups.

[0065] The term "hybrid aromatic group" refers to a group formed by the loss of two hydrogen atoms from an aromatic hydrocarbon containing one or more heteroatoms selected from N, O, S, etc., and having a specified number of atoms on the ring, such as a six- to thirty-membered hybrid aromatic group having 6 to 30 atoms on the ring. "Hybrid aromatic group" can include, but is not limited to, six- to thirty-membered hybrid aromatic groups, or six- to twenty-membered hybrid aromatic groups, or six- to fifteen-membered hybrid aromatic groups, or six- to ten-membered hybrid aromatic groups.

[0066] The term "aniline group" refers to a group derived from aniline compounds. For example, aniline compounds may include, but are not limited to, aniline, diphenylamine, triphenylamine, etc.

[0067] The term "nitrogen-containing aromatic heterocyclic group" refers to a group derived from an aromatic heterocyclic compound containing at least one nitrogen atom. This group may also include other heteroatoms such as O, S, P, Si, and B. For example, "nitrogen-containing aromatic heterocyclic group" may include, but is not limited to, carbazole groups, phenothiazine groups, phenoxazine groups, acridine groups, etc.

[0068] Unless otherwise specified, when "substituted" or "substituted" is used in this disclosure, there may be one or more substituents, such as one, two, three or more. Substituents may include, but are not limited to, one or more of the following: halogen, hydroxyl, mercapto, nitro, cyano, amino, sulfonic acid, carboxylic acid, ester, aldehyde, C1-C6 alkyl, C1-C6 alkoxy, five- to thirty-membered heteroaromatic groups, and six- to thirty-membered aromatic groups.

[0069] 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.

[0070] The photoelectric conversion principle of a solar cell is as follows: Incident light (e.g., sunlight) enters the device from the light-transmitting side, then reaches the light-absorbing layer and is absorbed. Excited by the incident light, the light-absorbing layer generates electron-hole pairs. Under the influence of an electric field, the holes and electrons separate; the electrons are transported to one electrode, while the holes are transported to the other electrode. A loop is then formed via an external circuit, which can be used to drive a load.

[0071] Deposition of self-assembled monolayers (SAMs) between the electrode layer and the light-absorbing layer, or between the hole transport layer and the light-absorbing layer, can not only passivate defects on the surface of the electrode layer or the hole transport layer, as well as defects on the lower surface of the light-absorbing layer, but also suppress interfacial redox reactions between certain high-valence elements (such as trivalent nickel) in the hole transport layer and the light-absorbing layer. Therefore, it has always been an important research direction for improving the efficiency of solar cells. However, self-assembled monolayers gradually detach as solar cells age, resulting in poor solar cell stability and consequently adversely affecting the photoelectric conversion efficiency.

[0072] Therefore, a technology is needed to reduce the risk of self-assembled monolayers falling off, thereby improving the stability and photoelectric conversion efficiency of solar cells.

[0073] Solar cells

[0074] Based on this, the present disclosure provides a solar cell. The solar cell layer includes a first electrode layer and a metal oxide layer stacked together, and a self-assembled monolayer, a light-absorbing layer, and a second electrode layer disposed on the metal oxide layer, wherein the hydroxyl index on the surface of the metal oxide layer is 2.5 to 4.5.

[0075] The term "self-assembled monolayer" refers to a two-dimensional monolayer that spontaneously forms on a substrate surface through physicochemical interactions between molecules and the substrate surface, as well as between molecules. Materials forming self-assembled monolayers typically include anchoring groups that can bond with the substrate. These anchoring groups may include oxyacid groups.

[0076] In the solar cell disclosed herein, the hydroxyl index on the surface of the metal oxide layer is 2.5–4.5, containing a relatively large number of hydroxyl groups. These hydroxyl groups can interact with anchoring groups in the SAM material, such as oxyacid groups, for example, through hydrogen bonding between hydroxyl groups and oxyacid groups, or through chemical bonding to form esters. This enhances the bonding force between the SAM layer and the metal oxide layer, reduces the risk of the SAM layer detaching as the solar cell ages, and thus improves the stability and photoelectric conversion efficiency of the solar cell.

[0077] In this disclosure, the hydroxyl index can be characterized by X-ray photoelectron spectroscopy (XPS). Specifically, the hydroxyl index is expressed as the peak intensity I of the hydroxyl (-OH) group at 532.2 eV in the X-ray photoelectron spectrum. OH The peak intensity I of saturated oxygen at 530.3 eV O2 The ratio I OH / I O2The hydroxyl index characterizes the number of hydroxyl groups. A higher hydroxyl index indicates a greater number of hydroxyl groups, while a lower hydroxyl index indicates a smaller number of hydroxyl groups. X-ray photoelectron spectroscopy (XPS) can be performed using commonly used XPS spectrometers in the field, such as the Shimadzu Kratos Axis Supra / Supra+ XPS spectrometer. For example, the method for determining the hydroxyl index can be found in the method described in ACS Energy Lett. 2020, 5, 2796-2801.

[0078] The hydroxyl index on the surface of the metal oxide layer is 2.5 to 4.5. Exemplarily, the hydroxyl index on the surface of the metal oxide layer can be 2.5, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.5, or any value within a range of two such values. Optionally, the hydroxyl index on the surface of the metal oxide layer can be 3.8 to 4.2. Controlling the hydroxyl index within the above range is beneficial in two ways: firstly, it helps to obtain a sufficient number of SAM layer anchor points, improving the stability of the solar cell; secondly, it helps to reduce the number of dangling bonds, reducing the negative impact of dangling bonds on the performance of the solar cell.

[0079] In some embodiments, the metal oxide layer includes one or more of nickel oxide, aluminum oxide, tin oxide, molybdenum oxide, cuprous oxide, vanadium oxide, tungsten oxide, and their doped or passivated derivatives. When nickel oxide, aluminum oxide, tin oxide, molybdenum oxide, cuprous oxide, vanadium oxide, or tungsten oxide are doped, the doping element can be a metallic or non-metallic element. Optionally, the doping element includes one or more of antimony, indium, copper, silver, cobalt, manganese, chromium, lithium, cesium, calcium, magnesium, strontium, barium, lead, or boron, but is not limited thereto.

[0080] In some embodiments, the metal oxide layer includes nickel oxide; aluminum oxide; tin oxide; or one or more of doped nickel oxide, aluminum oxide, and tin oxide. When nickel oxide, aluminum oxide, or tin oxide is doped, the doping element can be a metallic or non-metallic element. Optionally, the doping element includes one or more of antimony, indium, copper, silver, cobalt, manganese, chromium, lithium, cesium, calcium, magnesium, strontium, barium, lead, or boron, but is not limited thereto. The metal oxide layer is used herein as a hole transport layer for extracting and transporting holes, particularly for effectively transporting holes generated after photoexcitation of the light-absorbing layer to the first electrode layer and blocking electron transport.

[0081] In some embodiments, the thickness of the metal oxide layer can be from 5 nm to 20 nm. Exemplarily, the thickness of the metal oxide layer can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, or any value within a range of two such values. Controlling the thickness of the metal oxide layer within the aforementioned range is beneficial for forming a dense and continuous film, while also balancing light utilization and the ability of the metal oxide layer to extract holes.

[0082] In some embodiments, a self-assembled monolayer, a light-absorbing layer, and a second electrode layer are sequentially stacked on a metal oxide layer. In this way, the solar cell includes a first electrode layer, a metal oxide layer, a self-assembled monolayer, a light-absorbing layer, and a second electrode layer sequentially stacked.

[0083] This disclosure also provides a solar cell. The solar cell layer includes a first electrode layer and a self-assembled monolayer, a light-absorbing layer, and a second electrode layer disposed on the first electrode layer, wherein the hydroxyl index on the surface of the first electrode layer is 2.5 to 4.5.

[0084] In the solar cell disclosed herein, the hydroxyl index on the surface of the first electrode layer is 2.5–4.5, containing a relatively large number of hydroxyl groups. These hydroxyl groups can undergo physicochemical interactions with anchoring groups in the SAM material, such as oxyacid groups. For example, hydrogen bonding can occur between hydroxyl groups and oxyacid groups, or chemical bonding can occur to form esters. This enhances the bonding force between the SAM layer and the first electrode layer, reduces the risk of the SAM layer detaching as the solar cell ages, and thus improves the stability and photoelectric conversion efficiency of the solar cell.

[0085] In this disclosure, the test method for the hydroxyl index is as described above and will not be repeated here.

[0086] The hydroxyl index on the surface of the first electrode layer is 2.5 to 4.5. Exemplarily, the hydroxyl index on the surface of the first electrode layer can be 2.5, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.5, or any value within a range of two such values. Optionally, the hydroxyl index on the surface of the first electrode layer can be 3.8 to 4.2. Controlling the hydroxyl index within the above range is beneficial in two ways: firstly, it helps to obtain a sufficient number of SAM layer anchoring points, improving the stability of the solar cell; secondly, it helps to reduce the number of dangling bonds, reducing the negative impact of dangling bonds on the performance of the solar cell.

[0087] In some embodiments, a self-assembled monolayer, a light-absorbing layer, and a second electrode layer are sequentially stacked on a first electrode layer. In this way, the solar cell includes a first electrode layer, a self-assembled monolayer, a light-absorbing layer, and a second electrode layer sequentially stacked.

[0088] In some embodiments, the self-assembled monolayer comprises a compound represented by the general formula QLA, wherein Q is selected from one or more of substituted or unsubstituted aniline groups or substituted or unsubstituted nitrogen-containing aromatic heterocyclic groups; L is selected from one or more of substituted or unsubstituted alkylene groups, substituted or unsubstituted alkenyl groups, substituted or unsubstituted heteroalkylene groups, substituted or unsubstituted aromatic groups, or substituted or unsubstituted heteroaromatic groups; and A is selected from oxyacid groups and their salts or esters.

[0089] In some embodiments, the substituents of the substituted aniline group or nitrogen-containing aromatic heterocyclic group include one or more of the following: halogen group, oxyacid group, substituted or unsubstituted C1-C6 alkyl group, substituted or unsubstituted C1-C6 alkoxy group, substituted or unsubstituted six- to thirty-membered aromatic group, and substituted or unsubstituted five- to thirty-membered heteroaromatic group.

[0090] In some embodiments, the substituents of the substituted alkylene, alkenylene, heteroalkylene, aromatic, and heteroaromatic groups include one or more of halogen groups, oxyacid groups, C1-C6 alkyl groups, C1-C6 alkoxy groups, six- to thirty-membered aromatic groups, and five- to thirty-membered heteroaromatic groups.

[0091] In some embodiments, the oxyacid group is selected from one or more of phosphonic acid groups, hypophosphite groups, sulfonic acid groups, carboxylic acid groups, sulfinic acid groups, boric acid groups, or silicate groups.

[0092] In some embodiments, in the general formula QLA, Q is selected from substituted or unsubstituted carbazolyl or triphenylaminol, L is selected from substituted or unsubstituted alkylene groups, and A is selected from phosphonic acid groups.

[0093] In some embodiments, the substituents of the substituted carbazolyl or triphenylaminel group include one or more of the following: halogen group, oxyacid group, substituted or unsubstituted C1-C6 alkyl group, substituted or unsubstituted C1-C6 alkoxy group, substituted or unsubstituted hexa- to deca-aryl group, and substituted or unsubstituted penta- to deca-aryl heteroaryl group.

[0094] In some embodiments, the substituted or unsubstituted alkylene groups include any one of C1-C12 alkylene groups or C1-C12 alkylene groups substituted with halogen groups, oxyacid groups, C1-C6 alkyl groups, C1-C6 alkoxy groups, hexa- to deca-aryl groups, and penta- to deca-aryl heteroaryl groups.

[0095] For example, compounds represented by general formula QLA include one or more of the following: [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid, (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid, [4-(9H-carbazole-9-yl)butyl]phosphonic acid, (4-(3,6-dibromo-9H-carbazole-9-yl)butyl)phosphonic acid, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, (2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl)phosphonic acid, (2-(9H-carbazole-9-yl)ethyl)phosphonic acid, and (2-(3,6-dibromo-9H-carbazole-9-yl)ethyl)phosphonic acid.

[0096] In some embodiments, the self-assembled monolayer includes polymer-based self-assembling materials.

[0097] In some embodiments, the polymeric self-assembly material comprises structural units derived from compounds represented by the general formula QLA. The definitions of Q, L, and A are as described above and will not be repeated here.

[0098] The compounds and polymeric self-assembly materials represented by the general formula QLA can self-assemble into a monolayer, which is beneficial for effectively extracting charge carriers from the light-absorbing layer to the metal oxide layer and / or the first electrode layer through charge tunneling, thereby improving the photoelectric performance of solar cells.

[0099] In some embodiments, the self-assembled monolayer includes one or more of the following: [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid, (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid, [4-(9H-carbazole-9-yl)butyl]phosphonic acid, (4-(3,6-dibromo-9H-carbazole-9-yl)butyl)phosphonic acid, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, (2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl)phosphonic acid, (2-(9H-carbazole-9-yl)ethyl)phosphonic acid, and (2-(3,6-dibromo-9H-carbazole-9-yl)ethyl)phosphonic acid.

[0100] The first and second electrode layers are used to collect electrons / holes. In some embodiments, one of the first and second electrode layers 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. The transparent conductive material includes one or more of conductive oxides or conductive polymers. Exemplarily, the conductive oxide includes one or more of the following: tin oxide, indium tin oxide (ITO), indium zinc oxide (IZO), gallium zinc oxide (GZO), fluorine-doped tin oxide (FTO), indium-doped zinc oxide (IZO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), antimony-doped tin oxide, indium-doped tungsten oxide (IWO), indium-doped chromium oxide (ICrO), and indium-doped titanium oxide (ITiO). The conductive polymer includes one or more of poly(3,4-ethylenedioxythiophene) (PEDOT), polythiophene, and polyacetylene.

[0101] In some embodiments, the other of the first electrode layer and the second electrode layer may include the transparent conductive material described above or other conductive materials. This disclosure does not impose any particular limitation on other conductive materials. For example, other conductive materials include one or more of metals and their alloys, and carbonaceous materials. Exemplarily, metals and their alloys include one or more of gold, silver, copper, aluminum, nickel, chromium, bismuth, platinum, magnesium, molybdenum, tungsten, and their alloys. Exemplarily, carbonaceous materials include one or more of graphite, graphene, and carbon nanotubes.

[0102] In this disclosure, the thickness of the first electrode layer and the second electrode layer is not particularly limited, and the thickness of electrode layers commonly used in the art can be adopted. For example, the thickness of the first electrode layer and the second electrode layer can each be independently from 40 nm to 700 nm.

[0103] In some embodiments, the first electrode layer is a transparent electrode layer, or also referred to as the front electrode. Correspondingly, the second electrode layer is an electrode formed of other conductive materials as described above, or also referred to as the back electrode.

[0104] In some embodiments, the transparent electrode layer comprises one or more of conductive oxides or conductive polymers. Exemplarily, the conductive oxide includes one or more of tin oxide, indium tin oxide (ITO), indium zinc oxide (IZO), gallium zinc oxide (GZO), fluorine-doped tin oxide (FTO), indium-doped zinc oxide (IZO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), antimony-doped tin oxide, indium-doped tungsten oxide (IWO), indium-doped chromium oxide (ICrO), and indium-doped titanium oxide (ITiO). Exemplarily, the conductive polymer includes one or more of poly(3,4-ethylenedioxythiophene) (PEDOT), polythiophene, and polyacetylene. On these transparent electrode layers, it is advantageous to increase the hydroxyl index on their surface through an electrolytic reaction. This enhances the adhesion between the SAM layer and the first electrode layer, reduces the risk of the SAM layer detaching as the solar cell ages, and thereby improves the stability and photoelectric conversion efficiency of the solar cell.

[0105] An absorbing layer is disposed between the first electrode layer and the second electrode layer, and electron-hole pairs can be generated based on the excitation of incident light. This disclosure does not particularly limit the band gap of the absorbing layer; a band gap conventionally used in the art can be employed. For example, the band gap of the absorbing layer can be in the range of 1.17 eV to 2.30 eV. This disclosure does not particularly limit the band gap measurement method. For example, the band gap measurement method may include: first, obtaining an ultraviolet absorption curve through ultraviolet absorption spectroscopy; then calculating the band gap of the absorbing layer using the Tauc equation. This disclosure does not particularly limit the thickness of the absorbing layer; a thickness conventionally used in the art can be employed. For example, the thickness of the absorbing layer can be 500 nm to 800 nm.

[0106] In some embodiments, the light-absorbing layer includes a perovskite light-absorbing layer. Perovskite light-absorbing layers have strong light absorption properties and can readily release electrons, giving them potential advantages in photoelectric performance. This is beneficial for obtaining solar cells with high photoelectric conversion efficiency.

[0107] In some embodiments, the light-absorbing layer comprises a perovskite material. In some embodiments, the perovskite material comprises one or more of the compounds shown in formula [A][B][X]3 and [A]2[C][D][X]6, wherein A comprises one or more inorganic or organic monovalent cations, B comprises one or more inorganic divalent cations, C comprises one or more inorganic monovalent cations, D comprises one or more inorganic trivalent cations, and X comprises one or more inorganic anions.

[0108] 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 aromatic groups. Optionally, the organic monovalent cation includes (H2N=CH-NH2). + (abbreviated as FA), CH3NH3 + One or more of (abbreviated as MA).

[0109] For example, the inorganic monovalent cation includes: Li + Na + K + 、Rb + Cs + Cu + Ag + Au + or Hg + One or more of the following. Optionally, the inorganic monovalent cation includes Rb. + Cs + One or more of them.

[0110] 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+ One or more of the following. Optionally, the inorganic divalent cation includes Pb. 2+ Sn 2+ One or more of them.

[0111] For example, inorganic trivalent cations include: Bi 3+ Sb 3+ Cr 3+ Fe 3+ Co 3+ Ga 3+ As3+ Ru 3+ ,Rh 3+ In 3+ Ir 3+ Au 3+ Or Al 3+ One or more of them.

[0112] For example, inorganic anions include: F - Cl - ,Br - I - SCN - CNO - OCN - OSCN - SH - OH - CN - SeCN - One or more of the following. Optionally, inorganic anions include F. - Cl - ,Br - I - One or more of them.

[0113] In some embodiments, the light-absorbing layer includes: (FA) a MA 1-a ) b Cs 1-b Pb(I c Br 1-c )3, where 0≤a≤1, 0≤b≤1, 0≤c≤1, and FA represents (H2N=CH-NH2) + MA represents CH3NH3 + In some embodiments, the light-absorbing layer includes Cs. 0.15 FA 0.85 Pb(I 0.3 Br 0.7 3. (FA) 0.98 MA 0.02 ) 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 )3, CH3NH3PbI3, FAPbI3, (FA 0.83 MA 0.17 ) 0.95 Cs 0.05 Pb(I 0.83 Br 0.17 3. One or more of CsPbI3, CsPbI2Br, and CsPbIBr2. The band gap of the above-mentioned light-absorbing layer can be adjusted, which is beneficial to obtaining better photoelectric performance.

[0114] In some embodiments, the solar cell further includes an electron transport layer disposed between the light-absorbing layer and the second electrode layer. In these embodiments, the solar cell includes a first electrode layer, a metal oxide layer, a self-assembled monolayer, a light-absorbing layer, an electron transport layer, and a second electrode layer stacked sequentially; or the solar cell includes a first electrode layer, a self-assembled monolayer, a light-absorbing layer, an electron transport layer, and a second electrode layer stacked sequentially. The first electrode layer, the metal oxide layer, the self-assembled monolayer, the light-absorbing layer, and the second electrode layer are as described above and will not be repeated here.

[0115] An electron transport layer is disposed between the light-absorbing layer and the second electrode layer. It has the functions of transporting electrons and preventing hole transport. It is used to transport electrons generated after the light-absorbing layer is excited to the second electrode layer and to prevent holes from moving in the direction of electron movement, thereby facilitating the effective extraction and transport of photogenerated electrons.

[0116] 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 one or more 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 one or more of phthalimide, succinimide, N-bromosuccinimide, glutarimide, or maleimide. Exemplarily, quinone compounds include benzoquinone, naphthoquinone, phenanthrenequinone, or anthraquinone [6,6]-phenyl-C 61 One or more of methyl butyrate. Exemplarily, fullerenes and their derivatives include fullerene C. 60 [6,6]-phenyl-C 61 One or more of methyl butyrate (PCMB) are included. Exemplarily, the metal oxide includes one or more of Mg, Cd, Zn, In, Pb, W, Sb, Bi, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, or Cr. Optionally, the metal oxide includes one or more of tin dioxide (SnO2), titanium dioxide (TiO2), and zinc oxide (ZnO). Exemplarily, the semiconductor material oxide includes silicon oxide. Exemplarily, the titanate includes one or more of strontium titanate and calcium titanate. Exemplarily, the fluoride includes one or more of lithium fluoride and calcium fluoride.

[0117] 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 employed. For example, the thickness of the electron transport layer may be from 5 nm to 35 nm.

[0118] In some embodiments, the solar cell further includes a hole-blocking layer disposed between the electron transport layer and the second electrode layer. In these embodiments, the solar cell includes a first electrode layer, a metal oxide layer, a self-assembled monolayer, a light-absorbing layer, an electron transport layer, a hole-blocking layer, and a second electrode layer stacked sequentially; or the solar cell includes a first electrode layer, a self-assembled monolayer, a light-absorbing layer, an electron transport layer, a hole-blocking layer, and a second electrode layer stacked sequentially. The first electrode layer, the metal oxide layer, the self-assembled monolayer, the light-absorbing layer, the electron transport layer, and the second electrode layer are as described above and will not be repeated here.

[0119] A hole-blocking layer is disposed between the electron transport layer and the second electrode layer. The hole-blocking layer improves both electron extraction and hole blocking performance.

[0120] This disclosure does not impose any particular limitation on the hole blocking material used in the hole blocking layer; hole blocking materials commonly used in the art can be used. For example, the hole blocking material may include SnO2, ZnO, or CeO. x One or more of the following: BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline).

[0121] 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 employed. For example, the thickness of the hole blocking layer may be from 5 nm to 10 nm.

[0122] In some embodiments, the solar cell further includes a passivation layer disposed on at least one surface of the light-absorbing layer, which helps to reduce defects at the interface of the light-absorbing layer and further improve the performance of the solar cell.

[0123] The passivation layer may include passivating agents conventionally used in the art for passivating 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.

[0124] In some embodiments, the solar cell further includes a substrate layer disposed on the side of the first electrode layer away from the light-absorbing layer for supporting the solar cell. The substrate layer may be, but is not limited to, a glass substrate or a flexible substrate. In some embodiments, the flexible substrate layer may include, for example, but not limited to, organic polymer materials. Further, the flexible substrate layer may include one or more of the following materials mixed in different proportions: including but not limited to polyvinyl alcohol (PVA), polyethylene terephthalate (PET), polyimide (PI), polyethylene dinaphthalate (PEN), polydimethylsiloxane (PDMS), etc.

[0125] As an example, taking a solar cell comprising a first electrode layer, a metal oxide layer, a self-assembled monolayer, a light-absorbing layer, an electron transport layer, and a second electrode layer, a reverse testing method for the hydroxyl index is provided here. The method includes the following steps: 1. Take the solar cell module to be tested and remove the second electrode layer using tape. 2. Using a suitable solvent, such as chlorobenzene, drop it onto the solar cell module after removing the second electrode layer, and remove the electron transport layer by spin coating. 3. Using a suitable solvent, such as DMF, drop it onto the solar cell module after removing the electron transport layer, and remove the light-absorbing layer by spin coating. 4. Using a suitable solvent, such as ethanol, drop it onto the solar cell module after removing the light-absorbing layer, and remove the self-assembled monolayer by spin coating. 5. Dry the solar cell module after removing the self-assembled monolayer. 6. Characterize the hydroxyl index of the dried solar cell module using X-ray photoelectron spectroscopy (XPS). The XPS spectrum shows two distinct peaks for different oxygen species. The peak at 532.2 eV originates from hydroxyl groups (-OH) present on the surface of the metal oxide layer, while the peak at 530.3 eV originates from saturated oxygen in the metal oxide. The hydroxyl index is expressed as the ratio I of the intensity of the hydroxyl peak separated by XPS spectroscopy to the intensity of the saturated oxygen peak. OH / I O2 For example, the hydroxyl index can be tested using the method described in ACS Energy Lett. 2020, 5, 2796-2801.

[0126] Methods for preparing solar cells

[0127] This disclosure also provides a method for fabricating a solar cell. Figure 1 shows a flowchart of the method for fabricating a solar cell according to this embodiment. As shown in Figure 1, the method includes:

[0128] Provide a first electrode layer;

[0129] A metal oxide layer is prepared on the first electrode layer;

[0130] An electrolytic reaction is carried out on a metal oxide layer in an electrolytic cell, which includes an aqueous solution of inorganic salts as an electrolyte, to generate hydroxyl groups on the surface of the metal oxide layer.

[0131] A self-assembled monolayer was prepared on a metal oxide layer after electrolysis.

[0132] Preparation of light-absorbing layers on self-assembled monolayers; and

[0133] A second electrode layer is prepared on the light-absorbing layer.

[0134] In the method disclosed herein, hydroxyl groups are generated on the surface of the metal oxide layer by electrolytic reaction in an electrolytic cell comprising an aqueous solution of inorganic salts as the electrolyte, thereby increasing the hydroxyl index on the surface of the metal oxide layer. In the electrolytic cell, the metal oxide layer serves as the anode, and water molecules in the aqueous solution undergo an electron-loss reaction at the anode to generate hydroxyl groups. The reaction formula can be represented as H₂O-e - →·OH+H + This increases the hydroxyl index on the surface of the metal oxide layer.

[0135] Due to the increased hydroxyl index on the surface of the metal oxide layer, these hydroxyl groups can interact with oxyacid groups in the SAM material. For example, hydrogen bonding can occur between hydroxyl groups and oxyacid groups, or chemical bonding can occur to form esters. This enhances the bonding force between the SAM layer and the metal oxide layer, reducing the risk of the SAM layer detaching as the solar cell ages, thereby improving the photoelectric conversion efficiency and stability of the fabricated solar cell.

[0136] This disclosure also provides a method for fabricating a solar cell. Figure 2 shows a flowchart of the method for fabricating a solar cell according to this embodiment. As shown in Figure 2, the method includes:

[0137] Provide a first electrode layer;

[0138] An electrolytic reaction is carried out on the first electrode layer in an electrolytic cell, the electrolytic cell including an aqueous solution of inorganic salt as an electrolyte, so as to generate hydroxyl groups on the surface of the first electrode layer.

[0139] A self-assembled monolayer was prepared on the first electrode layer after the electrolysis reaction;

[0140] Preparation of light-absorbing layers on self-assembled monolayers; and

[0141] A second electrode layer is prepared on the light-absorbing layer.

[0142] In the method disclosed herein, hydroxyl groups can be generated on the surface of the first electrode layer by electrolyzing the first electrode layer in an electrolytic cell comprising an aqueous solution of inorganic salts as the electrolyte, thereby increasing the hydroxyl index on the surface of the first electrode layer. In the electrolytic cell, the first electrode layer serves as the anode, and water molecules in the aqueous solution undergo an electron-loss reaction at the anode to generate hydroxyl groups, the reaction formula of which can be represented as H₂O-e - →·OH+H + This increases the hydroxyl index on the surface of the first electrode layer.

[0143] Due to the increased hydroxyl index on the surface of the first electrode layer, these hydroxyl groups can interact with oxyacid groups in the SAM material. For example, hydrogen bonding can occur between hydroxyl groups and oxyacid groups, or chemical bonding can occur to form esters. This enhances the bonding force between the SAM layer and the first electrode layer, reduces the risk of the SAM layer detaching as the solar cell ages, and thus improves the photoelectric conversion efficiency and stability of the fabricated solar cell.

[0144] In some embodiments, the concentration of the inorganic salt in the aqueous solution can be 15–20 mg / mL. Exemplarily, this concentration can be 15 mg / mL, 16 mg / mL, 17 mg / mL, 18 mg / mL, 19 mg / mL, 20 mg / mL, or any value within a range of two such values. Controlling the concentration of the inorganic salt in the aqueous solution within the above range is beneficial for the electrolysis reaction to proceed at an appropriate reaction rate, reducing the influence of concentration polarization and improving reaction efficiency.

[0145] This disclosure does not impose any particular limitation on the type of inorganic salt; those commonly used in the electrolyte of electrolytic cells can be used. Exemplarily, the inorganic salt includes one or more of hydrochloride, hydrobromide, perchlorate, dihydrogen phosphate, persulfate, or persulfate. Exemplarily, the inorganic salt includes one or more of NaCl, KCl, NaBr, KBr, CsCl, CsBr, NaClO4, and KH2PO4, but is not limited thereto. Optionally, the inorganic salt includes NaCl.

[0146] In some embodiments, the electrolysis reaction is carried out at a voltage of 10V to 15V. Exemplarily, this voltage can be a value between 10V, 11V, 12V, 13V, 14V, 15V, or any two of these values. The electrolysis voltage is related to the rate of hydroxyl group generation. By carrying out the electrolysis reaction at a voltage within the aforementioned range, it is beneficial to obtain a suitable rate of hydroxyl group generation and to protect the performance of the functional layer in which the electrolysis reaction takes place.

[0147] In some embodiments, the electrolysis reaction is carried out for 1.6 min to 18 min. Exemplarily, the electrolysis reaction can be carried out for 1.6 min, 2.6 min, 3 min, 5 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, or any range of two such values. In the initial stage of the electrolysis reaction, the number of hydroxyl groups increases with the extension of reaction time. After a certain period of electrolysis, the increase in the hydroxyl index slows down and remains essentially constant. By carrying out the electrolysis reaction within the above-mentioned time range, it is beneficial to form a sufficient amount of hydroxyl groups on the surface of the functional layer on which the electrolysis reaction takes place, and it also helps to save time and improve operational efficiency.

[0148] In the electrolytic cell, there are no particular limitations on the electrode material used as the cathode; electrode materials conventionally used in the art can be used. For example, the cathode can be an Ag / AgCl electrode, a natural graphite electrode, a synthetic graphite electrode, a carbon electrode, or a special carbon electrode, etc.

[0149] There are no particular limitations on the method for preparing the metal oxide layer on the first electrode layer; any method conventional in the art can be used. Exemplary methods include chemical bath deposition, electrochemical deposition, chemical vapor deposition, physical epitaxial growth, thermal evaporation, atomic layer deposition, magnetron sputtering, spin coating, slot coating, blade coating, and mechanical pressing. Optionally, magnetron sputtering can be used to prepare the metal oxide layer.

[0150] There are no particular limitations on the method for preparing self-assembled monolayers; any method conventionally used in the art can be employed. Exemplary methods include spin coating, slot coating, and blade coating. Optionally, spin coating can be used to prepare the self-assembled monolayer. Alternatively, the self-assembled monolayer material can be dissolved in a solvent to obtain a solution, which is then applied to a metal oxide layer or a first electrode layer, followed by spin coating to prepare the self-assembled monolayer.

[0151] There are no particular limitations on the method for preparing the light-absorbing layer; any method conventional in the art can be used. For example, spin coating, slot coating, or blade coating can be employed. Optionally, spin coating can be used to prepare the light-absorbing layer. Optionally, a light-absorbing material precursor solution is first prepared, then applied to the self-assembled monolayer, and finally spin-coated to obtain the light-absorbing layer.

[0152] There are no particular limitations on the method for preparing the second electrode layer; any method conventionally used in the art can be employed. Exemplary methods include chemical bath deposition, electrochemical deposition, chemical vapor deposition, physical epitaxial growth, thermal evaporation, atomic layer deposition, magnetron sputtering, spin coating, slot coating, blade coating, and mechanical pressing. Optionally, thermal evaporation can be used to prepare the second electrode layer.

[0153] In some embodiments, the method of this disclosure further includes: preparing an electron transport layer on the light-absorbing layer. The method for preparing the electron transport layer is not particularly limited, and any method conventionally used in the art can be employed. Exemplarily, chemical bath deposition, electrochemical deposition, chemical vapor deposition, physical epitaxial growth, thermal evaporation, atomic layer deposition, magnetron sputtering, spin coating, slot coating, blade coating, mechanical pressing, etc., can be used. Optionally, thermal evaporation can be used to prepare the electron transport layer.

[0154] In some embodiments, the method of this disclosure further includes: fabricating a hole-blocking layer on the electron transport layer. The method for fabricating the hole-blocking layer is not particularly limited; any method conventionally used in the art can be employed. Exemplarily, methods such as chemical bath deposition, electrochemical deposition, chemical vapor deposition, physical epitaxial growth, thermal evaporation, atomic layer deposition, magnetron sputtering, spin coating, slot coating, blade coating, and mechanical pressing can be used.

[0155] In the method disclosed herein, the materials of the first electrode layer, metal oxide layer, self-assembled monolayer, light-absorbing layer, electron transport layer, hole blocking layer, and second electrode layer provided or prepared are as described above and will not be repeated here.

[0156] photovoltaic modules

[0157] This disclosure also provides a photovoltaic module, including the solar cells 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.

[0158] 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.

[0159] 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.

[0160] In some implementations, the battery encapsulation components include a photovoltaic backsheet. The photovoltaic backsheet serves to protect the solar cells.

[0161] 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.

[0162] In some implementations, the battery encapsulation component includes a solar panel aluminum frame, made of aluminum alloy, which features high strength and corrosion resistance. It serves to support and protect the solar cells.

[0163] Power generation unit

[0164] This disclosure also provides a power generation device, including the solar cell provided in the above embodiments.

[0165] Electrical appliances

[0166] This disclosure also provides an electrical device, including the solar cell provided in the above embodiments.

[0167] 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.

[0168] Example

[0169] 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.

[0170] Example 1

[0171] The following steps are used to prepare perovskite solar cells.

[0172] 1. Provide the first electrode layer

[0173] A fluorine-doped SnO2 conductive glass (FTO) measuring 10cm × 10cm was used as the first electrode layer. P1 was etched with an infrared nanosecond laser, with a width of 10μm and a sub-cell width of 5mm. After etching, the glass was ultrasonicated for 20min with a 1:50 mixture of conductive glass cleaner and deionized water, then rinsed three times with deionized water, followed by ultrasonication with isopropanol, acetone, and ethanol for 20min in sequence, and finally dried with N2 for later use.

[0174] 2. Preparation of metal oxide layer

[0175] A nickel oxide (NiOx) layer with a thickness of 18 nm was prepared on FTO conductive glass by magnetron sputtering, which served as a metal oxide layer for hole transport.

[0176] 3. Electrolytic reaction of the metal oxide layer

[0177] The metal oxide layer prepared in the previous step was placed in a 20 mg / mL NaCl aqueous solution. The metal oxide layer was used as the anode, and an Ag / AgCl electrode was used as the cathode. A voltage of 12 V was applied and maintained for 15 min. This generated hydroxyl groups on the metal oxide layer. The hydroxyl index on the surface of the metal oxide layer was measured by X-ray photoelectron spectroscopy. The test results are shown in Table 1 below.

[0178] 4. Preparation of self-assembled monolayers

[0179] 2 mg of (2-(9H-carbazole-9-yl)ethyl)phosphonic acid was dissolved in 10 mL of ethanol to prepare a solution with a concentration of 0.2 mg / mL. 500 μL of the prepared solution was dropped onto an electrolytically treated nickel oxide layer and spin-coated at 2000 rpm for 20 s. After spin-coating, the layer was placed on a hot plate and annealed at 80 °C for 5 min, then allowed to cool naturally to room temperature to obtain a self-assembled monolayer with a thickness of 3 nm.

[0180] 5. Preparation of perovskite light-absorbing layer

[0181] 60.2 mg (0.35 mmol) formamidin hydroiodate (FAI), 92.2 mg (0.2 mmol) lead iodide (PbI2), 38.9 mg (0.15 mmol) cesium iodide (CsI), 293.6 mg (0.8 mmol) lead bromide (PbBr2), and 62.5 mg (0.5 mmol) formamidin hydrobromide (FABr) were dissolved in a mixed solvent of 632 μL DMF and 368 μL DMSO to prepare CsI with a concentration of 1 M. 0.15 FA 0.85 Pb(I 0.3 Br 0.7 )3 perovskite precursor solution.

[0182] The multilayer structure obtained in step 4 was transferred to a glove box. 20 μL of the prepared perovskite precursor solution was dropped onto the self-assembled monolayer and spin-coated at 5000 rpm for 40 s. Then, 200 μL of the antisolvent chloroform was rapidly dropped onto the perovskite layer at 2000 rpm for 30 s. After spin-coating, the layer was annealed at 150 °C for 10 min to obtain a perovskite light-absorbing layer with a thickness of 500 nm.

[0183] 6. Fabrication of the electron transport layer

[0184] A 7 nm thick C layer was prepared on a perovskite light-absorbing layer using a thermal evaporation method. 60 Electron transport layer.

[0185] 7. Scratching of P2 channel

[0186] The P2 channel was etched using a 532nm laser with a width of 60μm.

[0187] 8. Fabrication of the second electrode layer

[0188] A copper (Cu) layer with a thickness of 40 nm was prepared on the electron transport layer as a second electrode layer using a thermal evaporation method.

[0189] 9. Scratching of P3 channels

[0190] The P3 channel was etched using a 532nm laser with a width of 10μm.

[0191] Thus, the perovskite solar cell of Example 1 was obtained.

[0192] Example 2

[0193] The perovskite solar cell of Example 2 was prepared using the same method as in Example 1, except that no metal oxide layer was prepared. Therefore, in the electrolysis reaction operation, the FTO conductive glass was electrolyzed to generate hydroxyl groups on the surface of the FTO conductive glass.

[0194] Example 3

[0195] The perovskite solar cell of Example 3 was prepared using the same method as in Example 1, except that an alumina (Al2O3) layer with a thickness of 18 nm was prepared on FTO conductive glass by magnetron sputtering during the preparation of the metal oxide layer. Therefore, hydroxyl groups were generated on the surface of the alumina layer during the electrolysis reaction.

[0196] Comparative Example 1

[0197] The perovskite solar cell of Comparative Example 1 was prepared using the same method as in Example 1, except that no electrolysis reaction was performed.

[0198] Comparative Example 2

[0199] The perovskite solar cell of Comparative Example 2 was prepared using the same method as in Example 2, except that no electrolysis reaction was performed.

[0200] Comparative Example 3

[0201] The perovskite solar cell of Comparative Example 3 was prepared using the same method as in Example 3, except that no electrolysis reaction was performed.

[0202] Hydroxyl index test

[0203] The hydroxyl index on the surface of the first electrode layer or the metal oxide layer was measured using a Shimadzu Kratos Axis Supra+ X-ray photoelectron spectrometer. The hydroxyl index is expressed as the peak intensity I of the hydroxyl (-OH) group at 532.2 eV in X-ray photoelectron spectroscopy (XPS). OH The peak intensity I of saturated oxygen at 530.3 eV O2 The ratio I OH / I O2 .

[0204] Testing the photoelectric performance of solar cells

[0205] The initial photoelectric conversion efficiency (PCE0) of the solar cell was tested under standard test conditions using a solar simulator, with a total irradiance of 100 mW / cm². 2 The spectral intensity was AM1.5G. Scanning tests were performed using a Keithley 2400SMU source meter, yielding V. OC J SC And FF. Then, calculate PCE0 based on the following formula: PCE0 = V OC ×J SC ×FF / P in ;

[0206] Where V OC J SC FF, P in These represent open-circuit voltage, short-circuit current density, fill factor, and incident light power density, respectively.

[0207] Testing the stability of solar cells

[0208] The photoelectric conversion efficiency (PCE) of a solar cell after being placed at 75°C for 200 hours was tested using the solar cell photoelectric performance test method described above. 200 @75℃. Efficiency retention rate = PCE 200 @75℃ / PCE0×100%.

[0209] The performance test results of the solar cells in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1 below.

[0210] Table 1: Performance test results of solar cells in Examples 1-3 and Comparative Examples 1-3

[0211] In Table 1, the symbol " / " indicates that no related items are involved.

[0212] As can be seen from the test results in Table 1, compared to the cases in Comparative Examples 1 to 3 where no electrolysis reaction was performed, in Examples 1 to 3, more hydroxyl groups were generated on the surface of the metal oxide layer in Examples 1 and 3 and on the surface of the first electrode layer in Example 2 through electrolysis reaction. Furthermore, the initial photoelectric conversion efficiency (PCE0) and efficiency retention after 200 hours of storage at 75°C in Examples 1 to 3 were also superior to those in Comparative Examples 1 to 3. This indicates that by increasing the hydroxyl index on the surface of the functional layer on which the SAM layer is deposited, the bonding force between the SAM layer and the functional layer is increased, which is beneficial for the SAM layer to better perform its function and reduces the risk of SAM layer detachment, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0213] Example 4

[0214] The perovskite solar cell of Example 4 was prepared using the same method as in Example 1, except that the voltage was applied continuously for 12 minutes instead of 15 minutes during the electrolysis reaction in step 3.

[0215] Example 5

[0216] The perovskite solar cell of Example 5 was prepared using the same method as in Example 1, except that the voltage was applied continuously for 18 minutes instead of 15 minutes during the electrolysis reaction in step 3.

[0217] Example 6

[0218] The perovskite solar cell of Example 6 was prepared using the same method as in Example 1, except that the voltage was continuously applied for 2.6 min instead of 15 min during the electrolysis reaction in step 3.

[0219] The hydroxyl index and photoelectric performance of the solar cells on the surface of the metal oxide layers in Examples 4 to 6 were tested using the above-described test methods. The test results are shown in Table 2 below.

[0220] Table 2: Performance test results of solar cells in Examples 1, 4-6

[0221] As can be seen from the test results in Table 2, different numbers of hydroxyl groups were generated on the surface of the metal oxide layer with different electrolysis times. Combined with Table 1, it can be seen that the hydroxyl index on the surface of the metal oxide layer in Examples 1, 4-6 is higher than that on the surface of the metal oxide layer in Comparative Example 1, which did not undergo electrolysis. Furthermore, the initial photoelectric conversion efficiency (PCE0) and efficiency retention rate after 200 hours of storage at 75°C in Examples 1, 4-6 are also better than those in Comparative Example 1.

[0222] 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 comprising a first electrode layer and a metal oxide layer disposed in a stack, and a self-assembled monolayer, a light-absorbing layer, and a second electrode layer disposed on the metal oxide layer, wherein, The hydroxyl index on the surface of the metal oxide layer is 2.5-4.

5.

2. The solar cell of claim 1, wherein, The hydroxyl index on the surface of the metal oxide layer is 3.8-4.

2.

3. The solar cell according to claim 1 or 2, wherein The metal oxide layer comprises one or more of nickel oxide, aluminum oxide, tin oxide, molybdenum oxide, cuprous oxide, vanadium oxide, tungsten oxide, and derivatives thereof doped or passivated.

4. The solar cell according to any one of claims 1 to 3, wherein, The thickness of the metal oxide layer is 5-20 nm.

5. A solar cell comprising a first electrode layer, and a self-assembled monolayer, a light-absorbing layer, and a second electrode layer disposed on the first electrode layer, wherein, The hydroxyl index on the surface of the first electrode layer is 2.5-4.

5.

6. The solar cell of claim 5, wherein, The hydroxyl index on the surface the first electrode layer is 3.8-4.

2.

7. The solar cell according to any one of claims 1 to 6, wherein, The self-assembled monolayer comprises a compound represented by a general formula Q-L-A, wherein, Q is selected from one or more of substituted or unsubstituted aniline-like groups or substituted or unsubstituted nitrogen-containing aromatic heterocyclic groups, L is selected from one or more of substituted or unsubstituted alkylene groups, substituted or unsubstituted alkenylene groups, substituted or unsubstituted heteroalkylene groups, substituted or unsubstituted aromatic groups, or substituted or unsubstituted heteroaromatic groups, A is selected from oxygen-containing acid groups and salts or esters thereof.

8. The solar cell of claim 7, wherein, The compound represented by the general formula Q-L-A satisfies one or more of the following conditions: The substituents of the substituted aniline-like groups or nitrogen-containing aromatic heterocyclic groups comprise one or more of halogen groups, oxygen-containing acid groups, substituted or unsubstituted C1-C6 alkyl groups, substituted or unsubstituted C1-C6 alkoxy groups, substituted or unsubstituted six- to thirty-membered aromatic groups, or substituted or unsubstituted five- to thirty-membered heteroaromatic groups; The substituents of the substituted alkylene groups, alkenylene groups, heteroalkylene groups, aromatic groups, or heteroaromatic groups comprise one or more of halogen groups, oxygen-containing acid groups, C1-C6 alkyl groups, C1-C6 alkoxy groups, six- to thirty-membered aromatic groups, or five- to thirty-membered heteroaromatic groups; or The oxygen-containing acid groups are selected from one or more of phosphonic acid groups, phosphinic acid groups, sulfonic acid groups, carboxylic acid groups, sulfinic acid groups, boric acid groups, or silicic acid groups.

9. The solar cell according to any one of claims 1 to 8, wherein, The self-assembled monolayer comprises one or more of [4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid, (4-(3,6-dimethyl-9H-carbazol-9-yl)butyl)phosphonic acid, [4-(9H-carbazol-9-yl)butyl]phosphonic acid, (2-(3,6-dibromo-9H-carbazol-9-yl)ethyl)phosphonic acid, [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid, (2-(3,6-dimethyl-9H-carbazol-9-yl)ethyl)phosphonic acid, (2-(9H-carbazol-9-yl)ethyl)phosphonic acid, or (2-(3,6-dibromo-9H-carbazol-9-yl))phosphonic acid.

10. The solar cell according to any one of claims 1 to 9, wherein, The first electrode layer is a transparent electrode layer.

11. The solar cell of claim 10, wherein, The transparent electrode layer comprises one or more of conductive oxides or conductive polymers.

12. The solar cell of claim 11, wherein, The conductive oxide includes one or more of tin oxide, indium tin oxide (ITO), indium zinc oxide (IZO), gallium zinc oxide (GZO), fluorine-doped tin oxide (FTO), indium-doped zinc oxide (IZO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), antimony-doped tin oxide, indium-doped tungsten oxide (IWO), indium-doped chromium oxide (ICrO), indium-doped titanium oxide (ITiO); and / or The conductive polymer includes one or more of poly(3,4-ethylenedioxythiophene) (PEDOT), polythiophene, polyacetylene.

13. The solar cell according to any one of claims 1 to 12, wherein, The solar cell further includes an electron transport layer disposed between the light absorbing layer and the second electrode layer.

14. The solar cell according to any one of claims 1 to 13, wherein, The light absorbing layer includes a perovskite light absorbing layer.

15. A method for preparing a solar cell, the method comprising: providing a first electrode layer; preparing a metal oxide layer on the first electrode layer; performing an electrolysis reaction on the metal oxide layer in an electrolytic cell including an aqueous inorganic salt solution as an electrolyte to generate hydroxyl groups on a surface of the metal oxide layer; preparing a self-assembled monolayer on the metal oxide layer after the electrolysis reaction; preparing a light absorbing layer on the self-assembled monolayer; and preparing a second electrode layer on the light absorbing layer.

16. A method for preparing a solar cell, the method comprising: providing a first electrode; performing an electrolysis reaction on the first electrode in an electrolytic cell including an aqueous inorganic salt solution as an electrolyte to generate a hydroxyl group on a surface of the first electrode; preparing a self-assembled monolayer on the first electrode after the electrolysis reaction; preparing a light absorbing layer on the self-assembled monolayers; and preparing a second electrode layer on the light absorbing layer. The concentration of the inorganic salt in the aqueous inorganic salt solution is 15 mg / mL to 20 mg / mL. The electrolysis reaction is performed at a voltage of 10 V to 15 V.

17. The method of claim 15 or 16, wherein, The electrolysis reaction is performed for 1.6 min to 18 min.

18. The method of any one of claims 15-17, wherein, 20. A photovoltaic module comprising the solar cell of any one of claims 1 to 14 or prepared by the method of any one of claims 15 to 19.

19. The method of any one of claims 15 to 18, wherein, 21. A power generation device comprising the solar cell of any one of claims 1 to 14 or prepared by the method any one of claims 15 to 19.

22. An electric consuming device comprising the solar cell of any one of claims 1 to 14 or prepared by the methods of any one of claims 15 to 19. ​ ​

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