Solar cell, photovoltaic module, power generation device, and electric device

Abstract

The present disclosure provides a solar cell, comprising: a hole transport layer and a perovskite light-absorbing layer which are stacked. The hole transport layer comprises a first compound, and the first compound comprises a Q1 group, an L1 group and an A1 group, wherein Q1 is selected from a substituted diphenylamino group, a thienyl group, a phenyl group, a carbazolyl group or a triphenylamino group; A1 is selected from an oxygen-containing acid group; and L1 is used for connecting the Q1 group and the A1 group. A second sublayer comprises a second compound, and the second compound comprises a Q2 group, an L2 group and an A2 group, wherein Q2 is selected from a substituted diphenylamino group, a thienyl group, a phenyl group, a benzocarbazolyl group, a carbazolyl group or a triphenylamino group; A2 is selected from an oxygen-containing acid group; and L2 is used for connecting the Q2 group and the A2 group. The present disclosure further relates to a photovoltaic module, a power generation device, and an electric device comprising the solar cell.

Description

Solar cells, photovoltaic modules, power generation devices, electrical appliances

[0001] Cross-reference to related applications

[0002] This disclosure is based on and claims priority to Chinese Patent Application No. 202411595492.3, filed on November 8, 2024, entitled “Solar Cell, Photovoltaic Module, Power Generation Device, 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, photovoltaic module, power generation device, and 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, 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. The solar cell includes a hole transport layer and a perovskite light-absorbing layer stacked together; wherein the hole transport layer includes a second sublayer and a first sublayer stacked sequentially along a direction gradually moving away from the perovskite light-absorbing layer, wherein the first sublayer includes a first compound, the first compound including a Q1 group, an L1 group, and an A1 group, wherein Q1 is selected from substituted diphenylamino, thiophene, phenyl, carbazole, or triphenylamino groups, A1 is selected from oxyacid groups, and L1 is used to connect the Q1 group and the A1 group; when Q1 is substituted, the substituents include… The first sublayer comprises C1-C12 alkyl groups, hexa- to deca-aryl groups, and halogens. The second sublayer comprises a second compound, which includes a Q2 group, an L2 group, and an A2 group. Q2 is selected from substituted diphenylamino, thiophene, phenyl, benzocarbazolyl, carbazolyl, or triphenylamino groups, A2 is selected from oxyacid groups, and L2 is used to connect the Q2 and A2 groups. When Q2 is substituted, the substituents include hydroxyl, carboxyl, amino, or -XR, where X includes O, S, N, and P, and R includes C1-C12 alkyl groups. By providing a hole transport layer comprising the above-mentioned first and second sublayers, where there is a difference in wettability and energy levels between the first and second sublayers, it is beneficial for the subsequent coating of the perovskite light-absorbing layer and hole transport, thereby improving the open-circuit voltage and photoelectric conversion efficiency of the battery.

[0009] In some embodiments, a first compound in the first sublayer is oriented, and a second compound in the second sublayer is oriented. The hole transport layer of the present invention comprises two oriented sublayers, thereby providing improved conductivity and hole transport performance, which in turn improves the open-circuit voltage and photoelectric conversion efficiency of the battery.

[0010] In some implementations, the sum-frequency generation spectrum of the hole transport layer is at a wavenumber of 1000 cm⁻¹. -1 ~4300cm -1 It has more than one peak within the range. Therefore, the hole transport layer has a high degree of orientation, thereby improving the hole transport performance of the hole transport layer.

[0011] In some embodiments, the difference between the contact angle of the first sublayer and the contact angle of the second sublayer is >10°. Therefore, the second sublayer has a smaller contact angle with the perovskite precursor solution compared to the first sublayer, resulting in better wettability of the perovskite precursor solution on the second sublayer and easier spreading thereon. This facilitates the formation of a uniform and consistent perovskite light-absorbing layer, which in turn benefits the open-circuit voltage and photoelectric conversion efficiency of the battery.

[0012] In some embodiments, the contact angle of the first sublayer is greater than or equal to 90°, and the contact angle of the second sublayer is less than 90°. This further facilitates the spread of the perovskite precursor solution on the second sublayer compared to the first sublayer, forming a uniform and consistent perovskite light-absorbing layer, which in turn benefits the open-circuit voltage and photoelectric conversion efficiency of the battery.

[0013] In some embodiments, the contact angle of the first sublayer is between 95° and 130°, and the contact angle of the second sublayer is between 30° and 70°. This is more conducive to the spreading of the perovskite precursor liquid on the second sublayer and to the formation of a uniform perovskite light-absorbing layer.

[0014] In some implementations, the HOMO level of the first sublayer is higher than that of the second sublayer. Thus, the second sublayer forms a "level buffer layer" between the first sublayer and the perovskite light-absorbing layer, which helps to lower the level barrier, improve the hole transport performance of the hole transport layer, and consequently improve the photoelectric conversion efficiency of the battery.

[0015] In some implementations, the difference between the HOMO energy level of the first sublayer and the HOMO energy level of the second sublayer is between 0.005 eV and 0.4 eV. This facilitates energy level matching between the second sublayer and the perovskite light-absorbing layer, and also facilitates the transition between the energy levels of the second and first sublayers, thereby improving charge transport.

[0016] In some implementations, the difference between the HOMO level of the first sublayer and the HOMO level of the second sublayer is between 0.050 eV and 0.20 eV. This facilitates a smoother transition between the energy levels of the second and first sublayers, thereby improving charge transport.

[0017] In some embodiments, L1 is selected from substituted or unsubstituted alkylene groups.

[0018] In some embodiments, L2 is selected from substituted or unsubstituted alkylene groups.

[0019] In some embodiments, in the first or second compound, the substituted or unsubstituted alkylene group includes any one of the following C1-C12 alkylene groups substituted or unsubstituted by a halogen, an oxyacid group, a C1-C5 alkyl group, a C1-C5 alkoxy group, a hexa-to-ten aryl group, or a penta-to-ten heteroaryl group.

[0020] In some embodiments, in the first or second compound, 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.

[0021] In some embodiments, the first compound comprises (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz), and the second compound comprises (4-(7H-dibenzocarbazole-7-yl)butyl)phosphonic acid (4PADCB).

[0022] In some embodiments, the first compound comprises (4-(3,6-dibromo-9H-carbazole-9-yl)butyl)phosphonic acid (Br-4PACz), and the second compound comprises (4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl)phosphonic acid (MeO-4PACz).

[0023] In some embodiments, the first compound comprises (4-(3,6-dibromo-9H-carbazole-9-yl)butyl)phosphonic acid (Br-4PACz), and the second compound comprises 4-(bis(4-(methylthio)phenyl)amino)phenylethylphosphonic acid (MeS-P3).

[0024] In some embodiments, the first compound comprises (2-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-2PACz), and the second compound comprises (4-(7H-dibenzocarbazole-7-yl)butyl)phosphonic acid (4PADCB).

[0025] In some embodiments, the first compound comprises (4-(3,6-diphenyl-9H-carbazole-9-yl)butyl)phosphonic acid (Ph-4PACz), and the second compound comprises (4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl)phosphonic acid (MeO-4PACz).

[0026] In some embodiments, the first compound comprises (2-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-2PACz), and the second compound comprises 4-(4-(bis(4-(methylthio)phenyl)amino)phenyl)butyric acid (MeS-C4).

[0027] In some implementations, the thickness of the first sublayer is 1 nm to 10 nm. This facilitates the formation of an oriented monolayer, thereby improving charge transport.

[0028] In some embodiments, the thickness of the second sublayer is 1 nm to 10 nm. This facilitates the formation of an oriented monolayer, thereby improving charge transport.

[0029] 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.

[0030] In some embodiments, the 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 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 and second electrodes, respectively, forming a loop via an external circuit for driving a load.

[0031] The second aspect of this disclosure provides a photovoltaic module, which includes the solar cell provided in the first aspect.

[0032] A third aspect of this disclosure provides a power generation device, which includes the solar cell provided in the first aspect.

[0033] The fourth aspect of this disclosure provides an electrical device that includes the solar cell provided in the first aspect.

[0034] 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

[0035] Figure 1 shows a schematic diagram of the structure of a solar cell according to an embodiment of the present disclosure.

[0036] Figure 2 shows the sum-frequency generated spectra of the second sublayer of Embodiment 1 of this disclosure and the second sublayer of Comparative Example 4.

[0037] 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; 1511: First sublayer; 1512: Second sublayer. Detailed Implementation

[0038] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the solar cells, photovoltaic modules, power generation devices, and power consumption devices 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.

[0039] 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, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0040] Unless otherwise specified, all embodiments and optional embodiments of this disclosure can be combined to form new technical solutions.

[0041] Unless otherwise specified, all technical features and optional technical features of this disclosure can be combined to form new technical solutions.

[0042] 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.

[0043] The term "electrode" refers to a region or layer that is composed of or is substantially composed of electrode material.

[0044] 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.

[0045] 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.

[0046] In this disclosure, the term "oriented distribution" refers to the ordered arrangement of material molecules in two dimensions. In this disclosure, the orientation of a material can be determined by sum-frequency generation spectroscopy (SFG). At a wavenumber of 1000 cm⁻¹... -1 ~4300cm -1 When more than one signal peak is generated within the range, it indicates an oriented distribution; in the case of non-oriented distribution, no signal peak is generated at all.

[0047] In this disclosure, the term "contact angle" refers to the angle between the solid-liquid interface, through the liquid interior, and at the solid-liquid-gas three-phase interface. The magnitude of the contact angle reflects the strength of the interaction between the liquid and the solid and is an important parameter for measuring the wettability of a liquid on a solid surface. In this disclosure, the "contact angle" is directly obtained by testing the spreadability of a perovskite precursor solution, such as a solution composed of 17.02 mg CsBr, 31.18 mg CsI, 39.99 mg FABr, 82.55 mg FAI, 139.46 mg PbBr2, 285.83 mg PbI2, and 1 mL of solvent (DMF:DMSO = 4:1, volume ratio), on a substrate, such as conductive glass or an organic molecular layer, using a contact angle measuring instrument.

[0048] In this disclosure, the term "HOMO (Highest Occupied Molecular Orbital) level" refers to the energy level of the highest energy orbital in a molecule that has occupied electrons. In this disclosure, the HOMO level of the analyte molecule can be directly measured using ultraviolet photoelectron spectroscopy (UPS) to test a thin film formed by spin-coating the analyte molecule. For example, a Thermo Fisher Scientific ESCALAB 250Xi UPS instrument can be used, with the test sample placed in the sample chamber of the UPS instrument (high vacuum environment, 10... -8 ~10-10 By using ultraviolet light to excite the valence band electrons on the sample surface, information such as the valence band position (VB / HOMO), work function (Ф), and ionization potential (IE) can be obtained. In UPS testing, the He I line (energy hν = 21.22 eV) is typically used as the excitation source, and the HOMO level can be determined by measuring the maximum value of the valence band of the sample.

[0049] In this disclosure, the term "alkyl" refers to a straight-chain or branched saturated aliphatic hydrocarbon group. The alkyl groups in this disclosure can be, for example, C1-C12 alkyl, C1-C9 alkyl, C1-C5 alkyl, C1-C4 alkyl, C1-C3 alkyl, and C1-C2 alkyl. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, sec-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl.

[0050] In this disclosure, the term "halogen" includes any one of F, Cl, Br, and I.

[0051] In this disclosure, the term "aryl" refers to an aromatic group having "4n+2" (π) electrons in a conjugated monocyclic or polycyclic system, such as "six- to ten-membered aryl" as described herein, which contains 6 to 10 carbon atoms. Examples of aryl groups include, but are not limited to, phenyl (Ph), naphthyl, indene, benzocyclooctenyl, benzocycloheptenyl, azulel, acenaphthel, fluorenyl, phenanthrene, anthracene, etc.

[0052] In this disclosure, the term "heteroaryl" refers to an aryl group in which one or more (preferably 1, 2, or 3) carbon atoms are replaced by oxygen, nitrogen, phosphorus, or sulfur atoms, such as "penta- to deca-aryl" as described herein, which contains 5 to 10 carbon atoms. Examples of heteroaryl groups include, but are not limited to, 4-pyridyl, 2-imidazolyl, thiophene, 3-pyrazolyl, and isoquinolinyl.

[0053] In this disclosure, the term "perovskite material" refers to a material having a three-dimensional crystal structure related to the three-dimensional crystal structure of CaTiO3, or a layered material comprising a structure related to the structure of CaTiO3. When incident light is received, electrons in the perovskite material are excited, and electrons jump from the valence band to the conduction band, generating electron-hole pairs.

[0054] Solar cells, also known as photovoltaic cells, are devices that directly convert light energy into electrical energy through the photoelectric effect or photochemical effect. Perovskite solar cells are solar cells that utilize perovskite material as the light-absorbing material. Compared to other solar cells, perovskite solar cells have advantages such as high photoelectric conversion efficiency and low cost. Unless otherwise specified, in the following text, "solar cell" refers to a solar cell whose light-absorbing layer contains perovskite material; it can also be called a perovskite solar cell.

[0055] The photoelectric conversion principle of a solar cell is as follows: Incident light (e.g., sunlight) enters the device and reaches the perovskite light-absorbing layer, where it is absorbed. 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, with the electrons being transferred to one electrode and the holes being transferred to the other electrode. Subsequently, a loop is formed through an external circuit, which can be used to drive the load.

[0056] Self-assembled monolayers (SAMs) are valuable for their ability to manipulate interfacial properties (such as adjusting work function, changing interfacial energy, and altering interfacial density of states) and their simple and scalable fabrication process, making them suitable for use as hole transport layers (HTLs) in perovskite solar cells. However, perovskite materials exhibit poor wettability on SAMs, hindering the spread of the perovskite light-absorbing layer solution and resulting in poor film formation and the inability to obtain continuous films. Therefore, improving the wettability of the perovskite layer on HTLs is still necessary to enhance the film quality of the perovskite layer, thereby improving the open-circuit voltage and photoelectric conversion efficiency of perovskite solar cells.

[0057] Based on this, the present disclosure provides a solar cell, a photovoltaic module, a power generation device, and a power consumption device. The present disclosure and its optional embodiments will be described in more detail below.

[0058] Solar cells

[0059] This disclosure provides a solar cell. The solar cell includes a hole transport layer and a perovskite light-absorbing layer stacked together; wherein the hole transport layer includes a second sublayer and a first sublayer stacked sequentially along a direction gradually moving away from the perovskite light-absorbing layer, the first sublayer including a first compound, the first compound including a Q1 group, an L1 group, and an A1 group, wherein Q1 is selected from substituted diphenylamino, thiophene, phenyl, carbazole, or triphenylamino groups, A1 is selected from oxyacid groups, and L1 is used to connect the Q1 group and the A1 group; when Q1 is substituted, the substituents include C1 to C12. Alkyl, six- to ten-membered aryl, halogen (F, Cl, Br or I); the second sublayer includes a second compound comprising a Q2 group, an L2 group and an A2 group, wherein Q2 is selected from substituted diphenylamino, thiophene, phenyl, benzocarbazolyl, carbazolyl or triphenylamino, A2 is selected from an oxyacid group, and L2 is used to connect the Q2 group and the A2 group; when Q2 is substituted, the substituents include hydroxyl, carboxyl, amino or -XR, wherein X includes O, S, N, P, and R includes C1 to C12 alkyl.

[0060] The hole transport layer has the function of extracting and transporting holes, used to transport holes generated by the excitation of the perovskite light-absorbing layer to the adjacent electrode and to block the transport of electrons. This is achieved by setting a hole transport layer comprising a first sublayer and a second sublayer, wherein the first sublayer comprises an organic molecule with nonpolar substituents (i.e., a first compound), and the second sublayer comprises an organic molecule with polar substituents (i.e., a second compound). Therefore, the first compound in the first sublayer, by having nonpolar groups, makes the organic molecules have little or no affinity for the solvent, resulting in relatively low wettability. Conversely, the second compound in the second sublayer, by having polar substituents, can form strong interactions with the solvent through, for example, hydrogen bonds, thus exhibiting relatively high wettability. The second sublayer, situated between the first and perovskite absorbing layers, provides a buffer between them, facilitating the spread of the perovskite precursor solution on the second sublayer and forming a uniform and consistent perovskite absorbing layer. Furthermore, the energy level difference between the first and second sublayers is beneficial for energy level matching between the hole transport layer and the perovskite absorbing layer, thereby improving the open-circuit voltage and photoelectric conversion efficiency of the battery.

[0061] In some embodiments, the first compound in the first sublayer is oriented, and the second compound in the second sublayer is oriented.

[0062] In the solar cell disclosed herein, the first and second sublayers, which are oriented in a specific direction, have improved conductivity, thereby increasing the carrier migration speed and efficiency, which in turn is beneficial to the photoelectric conversion efficiency of the device. At the same time, they are also beneficial to the morphology of the perovskite thin film formed thereon, making it more uniform and stable, thereby improving the open-circuit voltage of the device.

[0063] The orientation degrees of the first and second sublayers of the hole transport layer disclosed herein can be determined using instruments and methods known in the art. For example, using sum-frequency generation spectroscopy (SFG) at a wavenumber of 1000 cm⁻¹. -1 ~4300cm -1 The presence of more than one signal peak within the range indicates that the first or second sublayer, composed of the first or second compound, is oriented. If it is not oriented, no signal is generated.

[0064] In some implementations, the sum-frequency generation spectra of the first and second sublayers are at a wavenumber of 1000 cm⁻¹. -1 ~4300cm -1 It has more than one peak within the range. Therefore, the hole transport layer has a high degree of orientation, thereby improving the hole transport performance of the hole transport layer.

[0065] In some embodiments, both the first and second sublayers are prepared by solution processing. Thus, the first and second compound molecules are oriented in solution, thereby forming a stacked arrangement with the lowest energy.

[0066] In some embodiments, the difference between the contact angle of the first sublayer and the contact angle of the second sublayer is >10°. Therefore, the second sublayer has a smaller contact angle with the perovskite precursor solution compared to the first sublayer, resulting in better wettability of the perovskite precursor solution on the second sublayer and easier spreading thereon. This facilitates the formation of a uniform and consistent perovskite light-absorbing layer, which in turn benefits the open-circuit voltage and photoelectric conversion efficiency of the battery.

[0067] For example, the difference between the contact angle of the first sublayer and the contact angle of the second sublayer is a value between 11°, 15°, 20°, 30°, 38°, 40°, 50°, 60°, 68°, 77°, 80°, 100°, 120°, 140° or any two of these values, but is not limited thereto.

[0068] In some embodiments, the contact angle of the first sublayer is greater than or equal to 90°, and the contact angle of the second sublayer is less than 90°. This further facilitates the spread of the perovskite precursor solution on the second sublayer compared to the first sublayer, forming a uniform and consistent perovskite light-absorbing layer, which in turn benefits the open-circuit voltage and photoelectric conversion efficiency of the battery.

[0069] For example, the first sublayer contact angle is a value between 90°, 100°, 110°, 120°, 130°, or any two of these values, but is not limited thereto. Optionally, the first sublayer contact angle is greater than or equal to 95°.

[0070] For example, the contact angle of the second sublayer is 89°, 80°, 70°, 60°, 50°, 40°, 30°, or any value within a range of two such values, but is not limited thereto. Optionally, the contact angle of the second sublayer is less than 70°.

[0071] In some embodiments, the contact angle of the first sublayer is between 95° and 130°, and the contact angle of the second sublayer is between 30° and 70°. This is more conducive to the spreading of the perovskite precursor solution on the second sublayer, while the wettability of the second sublayer is maintained within a certain range so that the number of crystal nuclei formed is moderate and the grain size is moderate.

[0072] In some implementations, the HOMO level of the first sublayer is higher than that of the second sublayer. Therefore, the HOMO level of the second sublayer is lower than that of the first sublayer, effectively providing an energy level buffer layer between the first sublayer and the perovskite light-absorbing layer. This helps to lower the energy level barrier, improve the hole transport performance of the hole transport layer, and consequently improve the photoelectric conversion efficiency of the battery.

[0073] In some implementations, the difference between the HOMO energy level of the first sublayer and the HOMO energy level of the second sublayer is between 0.005 eV and 0.4 eV. This facilitates energy level matching between the second sublayer and the perovskite light-absorbing layer, and also facilitates the transition between the energy levels of the second and first sublayers, thereby improving charge transport.

[0074] For example, the difference between the HOMO energy level of the first sublayer and the HOMO energy level of the second sublayer is a value within a range of 0.005 eV, 0.01 eV, 0.02 eV, 0.04 eV, 0.06 eV, 0.08 eV, 0.1 eV, 0.2 eV, 0.3 eV, 0.4 eV, or any two of these values, but is not limited thereto. Optionally, the difference between the HOMO energy level of the first sublayer and the HOMO energy level of the second sublayer is between 0.050 eV and 0.20 eV. This facilitates energy level matching between the second sublayer and the perovskite light-absorbing layer, and also facilitates the transition between the energy levels of the second and first sublayers, thereby improving charge transport.

[0075] In some embodiments, the first compound is as shown in the general formula Q1-L1-A1, wherein L1 is used to connect the Q1 group and the A1 group, and is selected from one or more combinations of substituted or unsubstituted alkylene groups, substituted or unsubstituted C6-C30 aromatic rings, substituted or unsubstituted C5-C30 heteroaromatic rings, and substituted or unsubstituted alkenyl groups. In some embodiments, L1 is selected from substituted or unsubstituted alkylene groups.

[0076] In some embodiments, when Q1 is substituted, the substituent includes a C1-C12 alkyl group, a six- to ten-membered aryl group, or a halogen (F, Cl, Br, or I). In some embodiments, when Q1 is substituted, the substituent includes a methyl group. In some embodiments, when Q1 is substituted, the substituent includes a Br group. In some embodiments, when Q1 is substituted, the substituent includes a phenyl group.

[0077] In some embodiments, the second compound is as shown in the general formula Q2-L2-A2, wherein L2 is used to connect the Q2 group and the A2 group, and is selected from one or more combinations of substituted or unsubstituted alkylene groups, substituted or unsubstituted C6-C30 aromatic rings, substituted or unsubstituted C5-C30 heteroaromatic rings having two connection points, and substituted or unsubstituted alkenyl groups. In some embodiments, L2 is selected from substituted or unsubstituted alkylene groups. In some embodiments, when Q2 is substituted, the substituent includes a methoxy group. In some embodiments, when Q2 is substituted, the substituent includes a methylthio group.

[0078] In some embodiments, in the first or second compound, the substituted or unsubstituted alkylene group includes any one of the following C1-C12 alkylene groups substituted or unsubstituted by a halogen, an oxyacid group, a C1-C5 alkyl group, a C1-C5 alkoxy group, a hexa-to-ten aryl group, or a penta-to-ten heteroaryl group.

[0079] In some embodiments, in the first or second compound, 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.

[0080] In some embodiments, the first compound comprises (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz), and the second compound comprises (4-(7H-dibenzocarbazole-7-yl)butyl)phosphonic acid (4PADCB).

[0081] In some embodiments, the first compound comprises (4-(3,6-dibromo-9H-carbazole-9-yl)butyl)phosphonic acid (Br-4PACz), and the second compound comprises (4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl)phosphonic acid (MeO-4PACz).

[0082] In some embodiments, the first compound comprises (4-(3,6-dibromo-9H-carbazole-9-yl)butyl)phosphonic acid (Br-4PACz), and the second compound comprises 4-(bis(4-(methylthio)phenyl)amino)phenylethylphosphonic acid (MeS-P3).

[0083] In some embodiments, the first compound comprises (2-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-2PACz), and the second compound comprises (4-(7H-dibenzocarbazole-7-yl)butyl)phosphonic acid (4PADCB).

[0084] In some embodiments, the first compound comprises (4-(3,6-diphenyl-9H-carbazole-9-yl)butyl)phosphonic acid (Ph-4PACz), and the second compound comprises (4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl)phosphonic acid (MeO-4PACz).

[0085] In some embodiments, the first compound comprises (2-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-2PACz), and the second compound comprises 4-(4-(bis(4-(methylthio)phenyl)amino)phenyl)butyric acid (MeS-C4).

[0086] In some implementations, the thickness of the first sublayer is 1 nm to 10 nm. This facilitates the formation of an oriented monolayer, which is beneficial for charge transport.

[0087] In some embodiments, the thickness of the second sublayer is 1 nm to 10 nm. This facilitates the formation of an oriented monolayer, which is beneficial for charge transport.

[0088] In some embodiments, the hole transport layer further includes a third sublayer disposed between the first electrode and the first sublayer. This disclosure does not impose any particular limitation on the material of the third sublayer; hole transport materials commonly used in the art, such as metal oxides, can be used. Here, there is no particular limitation on the metal oxide; any metal oxide that is commonly used as a hole transport material is acceptable. Exemplarily, metal oxides include nickel oxide, molybdenum oxide, tungsten oxide, etc.

[0089] In some embodiments, the thickness of the metal oxide layer is 10 nm to 100 nm. Exemplarily, the thickness of the metal oxide layer can be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, or any value within a range of two such values. This further improves the photoelectric conversion efficiency and stability of perovskite solar cells.

[0090] 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 total thickness of the hole transport layer is from 2 nm to 200 nm.

[0091] 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.

[0092] The perovskite solar cell of this disclosure will be further described below with reference to the accompanying drawings.

[0093] 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 hole transport layer 151, a perovskite light-absorbing layer 13, and a second electrode 12, wherein the first electrode 11 and the second electrode 12 have opposite polarities. The hole transport layer 151 includes a first sublayer 1511 and a second sublayer 1512.

[0094] 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 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, the transparent conductive material includes 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.

[0095] 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.

[0096] In some embodiments, the first electrode 11 is a transparent electrode that first receives incident light. When used to collect holes, the resulting perovskite cell is an inverted perovskite solar cell (pin).

[0097] In other embodiments, the second electrode 12 is a transparent electrode that first receives incident light. When used to collect electrons, the resulting perovskite cell is a formal perovskite solar cell (nip). 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.

[0098] 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.

[0099] The perovskite light-absorbing layer 13 comprises a perovskite material. In some embodiments, the perovskite material comprises at least one of the 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.

[0100] 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).

[0101] For example, the inorganic monovalent cation includes: Li + Na + K + 、Rb + Cs + Cu + Ag + Au + or Hg + At least one of them.

[0102] 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.

[0103] 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.

[0104] For example, monovalent anions include: F - Cl - ,Br - I - SCN - CNO - OCN - OSCN - SH - OH - CN - SeCN - At least one of them.

[0105] In some embodiments, the perovskite light-absorbing layer comprises a compound of formula (I): [A][B][X]3 (I);

[0106] A includes FA, MA, and Cs. + At least two of them, B is Pb 2+ X includes Cl - ,Br - I - At least two of them, FA represents (H2N=CH-NH2). + MA represents CH3NH3 + This makes it easier to match the energy levels of the hole transport layer and the perovskite light-absorbing layer, reducing the energy level barrier and thus improving the hole transport performance of the hole transport layer.

[0107] In some embodiments, the perovskite light-absorbing layer includes FA. 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 3.

[0108] 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.

[0109] In some embodiments, the solar cell of this disclosure further includes an electron transport layer disposed on the side of the perovskite light-absorbing layer facing the second electrode. 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 prevent the transport of holes.

[0110] 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.

[0111] 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.

[0112] 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]-phenylC61 Methyl butyrate (PC) 61 BM), [6,6]-phenyl C 71 Methyl butyrate (PC) 71 BM), Fullerene C 60 Fullerene C 70 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.

[0113] 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.

[0114] 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).

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] Methods for preparing solar cells

[0121] This disclosure also provides a method for preparing a solar cell, comprising providing a first electrode; forming a first sublayer on the first electrode using a solution containing a first compound; and forming a second sublayer on the first sublayer using a solution containing a second compound, wherein the first compound comprises a Q1 group, an L1 group, and an A1 group, wherein Q1 is selected from substituted diphenylamino, thiophene, phenyl, carbazole, or triphenylamino groups, A1 is selected from oxyacid groups, and L1 is used to connect the Q1 group and the A1 group; wherein Q1 is substituted... In this case, the substituents include C1-C12 alkyl, six- to ten-membered aryl, and halogen; the second compound includes a Q2 group, an L2 group, and an A2 group, wherein Q2 is selected from substituted diphenylamino, thiophene, phenyl, benzocarbazolyl, carbazolyl, or triphenylamino, A2 is selected from oxyacid groups, and L2 is used to connect the Q2 group and the A2 group; when Q2 is substituted, the substituents include hydroxyl, carboxyl, amino, or -XR, wherein X includes O, S, N, and P, and R includes C1-C12 alkyl.

[0122] In this disclosure, the hole transport layer is prepared by using a solution of the above-mentioned compound to form a film, which is simple and results in the compounds in the two sublayers being oriented.

[0123] In some embodiments, the concentration of the solution containing the first compound is 0.1 mol / L to 1 mol / L. This facilitates the formation of a first sublayer of monolayer, without molecular stacking. Exemplarily, the concentration of the solution of the first compound is 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L, 1.0 mol / L, or any range of two such values, but is not limited thereto. Optionally, the concentration of the solution of the first compound is 0.3 mol / L to 0.6 mol / L.

[0124] In some embodiments, the concentration of the solution containing the second compound is 0.1 mol / L to 1 mol / L. This facilitates the formation of a second sublayer monolayer, eliminating molecular stacking. Exemplarily, the concentration of the solution containing the second compound is 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L, 1.0 mol / L, or any range of two such values, but is not limited thereto. Optionally, the concentration of the solution containing the second compound is 0.3 mol / L to 0.6 mol / L.

[0125] In some embodiments, forming the first sublayer includes performing a first annealing at 50°C to 150°C. This facilitates thorough removal of surface solvent, resulting in a more stable first sublayer. Exemplarily, the first annealing temperature is a value between 50°C, 70°C, 90°C, 100°C, 120°C, 140°C, 150°C, or any two of these values, but is not limited thereto.

[0126] In some embodiments, forming the second sublayer includes performing a second annealing at 50°C to 150°C. This facilitates thorough removal of surface solvent, resulting in a more stable second sublayer. Exemplarily, the second annealing temperature is a value between 50°C, 70°C, 90°C, 100°C, 120°C, 140°C, 150°C, or any two of these values, but is not limited thereto.

[0127] In some embodiments, the first annealing time is between 3 and 15 minutes. This facilitates thorough solvent removal. Exemplarily, the first annealing time is a value between 3 minutes, 5 minutes, 7 minutes, 10 minutes, 15 minutes, or any two of these values, but is not limited thereto.

[0128] In some embodiments, the second annealing time is between 3 and 15 minutes. This facilitates thorough solvent removal. Exemplarily, the second annealing time is a value between 3 minutes, 5 minutes, 7 minutes, 10 minutes, 15 minutes, or any two of these values, but is not limited thereto.

[0129] In some embodiments, the perovskite solar cell of this disclosure can be obtained by the following preparation method. This preparation method includes the following steps:

[0130] Step S1: Provide a transparent conductive glass substrate as the first electrode, and perform pretreatment such as etching, cleaning and drying on the transparent conductive glass substrate for later use;

[0131] Step S2: Prepare the first sublayer on the pretreated transparent conductive glass substrate;

[0132] Step S3: Prepare a second sublayer on the first sublayer. The first and second sublayers constitute a hole transport layer.

[0133] Step S4: Prepare a perovskite light-absorbing layer on the hole transport layer;

[0134] Optionally, step S5: prepare an electron transport layer on the perovskite light-absorbing layer;

[0135] Optionally, step S6: fabricating a hole-blocking layer on the electron transport layer; and

[0136] Step S7: Fabricate a metal electrode as a second electrode on the perovskite light-absorbing layer, or, if present, an electron transport layer, or, if present, a hole-blocking layer;

[0137] This is how solar cells are obtained.

[0138] The fabrication methods for the various functional layers of a solar cell, such as the first electrode, perovskite light-absorbing layer, electron transport layer, hole blocking layer, and second electrode, are not particularly limited and can include fabrication methods commonly 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.

[0139] photovoltaic modules

[0140] 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.

[0141] 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.

[0142] 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.

[0143] In some implementations, the battery encapsulation components include a photovoltaic backsheet. The photovoltaic backsheet serves to protect the solar cells.

[0144] 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.

[0145] 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.

[0146] Power generation unit

[0147] 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.

[0148] Electrical appliances

[0149] 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.

[0150] 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.

[0151] Example

[0152] 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.

[0153] Example 1

[0154] 1. Provide the first electrode

[0155] A 2.0cm × 2.0cm FTO conductive glass substrate (i.e., fluorine-doped SnO2 transparent metal oxide) was taken, and 0.35cm of FTO was removed from each end 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.

[0156] 2. Preparation of the hole transport layer

[0157] 85 μL of an ethanol solution of Me-4PACz (0.5 mg / mL) was dropped onto an FTO conductive glass substrate, spin-coated at 2000 rpm for 30 seconds, and annealed at 100 °C for 10 minutes to obtain a first sublayer with a thickness of 7 nm.

[0158] 85 μL of an ethanol solution of 4 PADCB (0.3 mg / mL) was added dropwise to the first sublayer, and the mixture was spin-coated at 3000 rpm for 25 seconds. The mixture was then annealed at 100 °C for 10 minutes to obtain a second sublayer with a thickness of 5 nm.

[0159] The first and second sublayers mentioned above together constitute the hole transport layer.

[0160] 3. Preparation of the perovskite light-absorbing layer

[0161] 17.02 mg CsBr, 31.18 mg CsI, 39.99 mg FABr, 82.55 mg FAI, 139.46 mg PbBr2, and 285.83 mg PbI2 were dissolved in 1 mL of a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) (DMF:DMSO volume ratio 4:1) and stirred for 2 hours. The solution was filtered through a 0.22 μm organic filter membrane to obtain a perovskite precursor solution. Under a nitrogen atmosphere, 95 μL of the perovskite precursor solution was dropwise added to the hole transport layer and spin-coated at 5000 rpm for 25 seconds. The mixture was then subjected to vacuum flash evaporation for 30 seconds and annealed at 100 °C for 15 min to obtain a FABr layer with a thickness of 450 nm. 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 )3 Perovskite light-absorbing layer.

[0162] 4. Fabrication of electron transport layer, hole blocking layer, and second electrode

[0163] On the perovskite layer, a 25 nm fullerene (C60) layer is deposited sequentially as an electron transport layer, an 8 nm 2,9-dimethyl-4,7-biphenyl-1,10-o-diazaphenanthroline (BCP) layer is deposited as a barrier layer, and a 100 nm Cu electrode is deposited as a second electrode.

[0164] Thus, perovskite solar cells were obtained.

[0165] Examples 2 to 6

[0166] Solar cells were prepared using a method similar to that in Example 1, except that the materials shown in Table 1 were used to prepare the first and second sublayers.

[0167] Comparative Example 1

[0168] The solar cell was prepared using the same method as in Example 1, except that the hole transport layer was prepared by the following method: 85 μL of an ethanol solution of Me-4PACz (0.86 mg / mL) was dropped onto an FTO conductive glass substrate, spin-coated at 2000 rpm for 30 seconds, and annealed at 100°C for 10 minutes to obtain a hole transport layer with a thickness of 12 nm. That is, the hole transport layer consists of only one layer.

[0169] Comparative Example 2

[0170] The solar cell was prepared using the same method as in Example 1, except that the hole transport layer was prepared by the following method: 85 μL of an ethanol solution of 4 PADCB (1.2 mg / mL) was dropped onto an FTO conductive glass substrate, spin-coated at 3000 rpm for 25 seconds, and annealed at 100°C for 10 minutes to obtain a hole transport layer with a thickness of 12 nm. That is, the hole transport layer consists of only one layer.

[0171] Comparative Example 3

[0172] The solar cell was prepared using the same method as in Example 1, except that the hole transport layer was prepared by the following method: 85 μL of an ethanol solution of Me-4PACz and 4PADCB (where the concentration of Me-4PACz was 1.0 mg / mL and the concentration of 4PADCB was 0.6 mg / mL) was dropped onto an FTO conductive glass substrate, spin-coated at 2000 rpm for 30 seconds, and annealed at 100°C for 10 minutes to obtain a hole transport layer with a thickness of 12 nm. That is, the hole transport layer consists of only one layer.

[0173] Comparative Example 4

[0174] The solar cell was prepared using the same method as in Example 1, except that the hole transport layer was prepared by the following method: 85 μL of an ethanol solution of Me-4PACz (0.5 mg / mL) was dropped onto an FTO conductive glass substrate, spin-coated at 2000 rpm for 30 seconds, and annealed at 100°C for 10 minutes to obtain a first sublayer with a thickness of 7 nm; a 5 nm thick 4PADCB was deposited on the first sublayer using an evaporation machine as a second sublayer. The first and second sublayers together constitute the hole transport layer.

[0175] Characterization of the hole transport layer

[0176] 1. Characterization of sum-frequency generation spectra

[0177] The hole transport layers of the examples and comparative examples were tested using sum-frequency generated spectroscopy (SFG).

[0178] Test instruments and procedures: A laser (Chameleon Ultra II, Coherent, pulse width 140 femtoseconds, repetition frequency 80MHz) was used to excite light with a wavelength range from 700nm to 1050nm; an optical parametric oscillator (Chameleon, adjustable range 1000-1600nm) was used for infrared light excitation.

[0179] Before entering the inverted microscope (Nikon Eclipse Ti, 100× objective, NA=0.9), the laser beam was purified using a short-pass filter (Semrock). The sample was placed on the piezoelectric stage (E-710.4CD, Physik Instrumente GmbH, Germany) and illuminated with a focused spot with a radius of approximately 1 μm. The emission signals emitted by the sample (including second harmonic generation SHG, third harmonic generation THG, and two-photon excited fluorescence 2PPL) were purified using a 790 nm short-pass emission filter (Semrock) to remove scattered laser beams before being coupled and measured by a monochromator (Acton, Spectra Pro 2300i) to a charge-coupled device CCD (Princeton Instruments, Pixis 100B).

[0180] Sample preparation: Prepare a sample for the solid surface to be studied.

[0181] Setting up the spectrometer: Adjust the infrared and visible beams of the SFG spectrometer to the desired frequencies and ensure that they are correctly overlapped on the sample surface.

[0182] Adjust parameters: Adjust the laser energy, wavelength, pulse width, and polarization state to optimize signal quality and intensity.

[0183] Data collection: SFG spectral data is collected by scanning the frequency of the infrared beam and simultaneously recording the intensity of the frequency signal.

[0184] Data analysis: Analyzing the collected spectral data.

[0185] Interpretation of Results: Based on the characteristics of the SFG spectrum, the molecular structure and dynamic processes at the interface were inferred. (At a wavenumber of 1000 cm⁻¹) -1 ~4300cm -1 The presence of more than one peak within the range indicates that the first or second sublayer, composed of compound molecules, is oriented. If it is not oriented, no signal is generated.

[0186] The first and second sublayers of embodiments 1 to 6 of this disclosure are at a wavenumber of 1000 cm⁻¹. -1 ~4300cm -1 Each layer has more than one peak. As shown in Figure 2, the second sublayer of Example 1 has four peaks.

[0187] The hole transport layers of Comparative Examples 1-3 and the first sublayer of Comparative Example 4 all operate at a wavenumber of 1000 cm⁻¹. -1 ~4300cm -1 The signal peaks are present in the range of 2800-3200 cm⁻¹, but as shown in Figure 2, the second sublayer of Comparative Example 4 has no signal peaks. Here, considering the structural characteristics of the compounds used in Example 1 and Comparative Example 4, Figure 2 shows the four peaks of the second sublayer in Example 1, specifically those in the 2800-3200 cm⁻¹ range. -1 The spectrum is within the range, but it should be understood that the second sublayer of Comparative Example 4 is at 1000 cm⁻¹. -1 ~4300cm -1 There were no signal peaks across the entire range.

[0188] 2. Characterization of HOMO level differences

[0189] The HOMO level can be measured using ultraviolet photoelectron spectroscopy (UPS, Thermo Fisher Scientific ESCALAB 250Xi).

[0190] Sample preparation: The samples from the first and second sublayers obtained above were used as test samples, ensuring that the sample surfaces were clean and free of contamination.

[0191] Vacuum conditions: Place the test sample into the sample chamber of the UPS instrument (high vacuum environment, 10...). -8 ~10 -10 mbar),

[0192] Sample positioning: Place the sample on the sample stage of the UPS instrument and ensure good electrical contact between the sample and the instrument.

[0193] Energy calibration: Energy calibration is performed using a standard sample (gold) to ensure the accuracy of the measurement data.

[0194] Excitation source selection: Helium lamp He I is used as the excitation source. The photon energy of the He I line is 21.22 eV, which is suitable for measuring the valence band position.

[0195] Data Acquisition: By exciting the valence band electrons on the sample surface with ultraviolet light, the valence band position (VB / HOMO), work function (Ф), and ionization potential (IE) of the sample can be obtained. The HOMO energy level can be determined by measuring the maximum valence band value. For the sample under test, the HOMO energy level can be determined by linear extrapolating from the steep rise of the valence band starting edge in the UPS spectrum and taking its intersection with the background noise baseline.

[0196] HOMO level difference = HOMO level of the first sublayer - HOMO level of the second sublayer.

[0197] 3. Contact angle characterization

[0198] The hole transport layer was tested using an SDC-200S contact angle meter from Shengding Precision Technology Co., Ltd. A drop of perovskite precursor solution (composed of 17.02 mg CsBr, 31.18 mg CsI, 39.99 mg FABr, 82.55 mg FAI, 139.46 mg PbBr2, 285.83 mg PbI2, and 1 mL of solvent (DMF:DMSO = 4:1)) was added to the surface of the layer to be tested, and the contact angle of the droplet was read.

[0199] The test results of the HOMO energy level and contact angle of the hole transport layer in Examples 1 to 6 and Comparative Examples 1 to 4 are shown in Table 1 below.

[0200] Table 1

[0201] Testing the photoelectric performance of solar cells

[0202] 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.

[0203] Following the international standard IEC 61215, using a solar simulator from Guangyan, the light intensity of crystalline silicon solar cells was corrected to achieve one 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 SCAnd FF, and calculate the initial photoelectric conversion efficiency (PCE) of the solar cell using the following formula:

[0204] Among them, P input This represents the incident light power density.

[0205] The performance test results of the solar cells of Examples 1 to 6 and Comparative Examples 1 to 4 are shown in Table 2 below.

[0206] Table 2

[0207] Based on the above results, it can be seen that the solar cell disclosed herein has improved open-circuit voltage (Voc) and photoelectric conversion efficiency (PCE).

[0208] 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 hole transport layer and a perovskite light-absorbing layer stacked together, in, The hole transport layer comprises a second sublayer and a first sublayer stacked sequentially along a direction gradually moving away from the perovskite light-absorbing layer. The first sublayer comprises a first compound, which comprises a Q1 group, an L1 group, and an A1 group. Q1 is selected from substituted diphenylamino, thiophene, phenyl, carbazole, or triphenylamino groups, A1 is selected from oxyacid groups, and L1 is used to connect the Q1 group and the A1 group. When Q1 is substituted, the substituents include C1-C12 alkyl, hexa- to deca-aryl, and halogens. The second sublayer includes a second compound comprising a Q2 group, an L2 group, and an A2 group, wherein Q2 is selected from substituted diphenylamino, thiophene, phenyl, benzocarbazolyl, carbazolyl, or triphenylamino, A2 is selected from an oxyacid group, and L2 is used to connect the Q2 group and the A2 group; when Q2 is substituted, the substituents include hydroxyl, carboxyl, amino, or -XR, wherein X includes O, S, N, or P, and R includes C1 to C12 alkyl groups.

2. The solar cell according to claim 1, wherein, The first compound in the first sublayer is oriented, and the second compound in the second sublayer is oriented.

3. The solar cell according to claim 2, wherein, The sum-frequency generation spectra of the first and second sublayers at wavenumber 1000 cm⁻¹ -1 ~4300cm -1 It has more than one peak within the range.

4. The solar cell according to any one of claims 1 to 3, wherein, The difference between the contact angle of the first sublayer and the contact angle of the second sublayer is >10°.

5. The solar cell according to claim 4, wherein, The contact angle of the first sublayer is greater than or equal to 90°, and the contact angle of the second sublayer is less than 90°.

6. The solar cell according to claim 5, wherein, The contact angle of the first sublayer is between 95° and 130°, and the contact angle of the second sublayer is between 30° and 70°.

7. The solar cell according to any one of claims 1 to 6, wherein, The HOMO energy level of the first sublayer is greater than the HOMO energy level of the second sublayer.

8. The solar cell according to claim 7, wherein, The difference between the HOMO energy level of the first sublayer and the HOMO energy level of the second sublayer is between 0.005 eV and 0.4 eV.

9. The solar cell according to claim 7 or 8, wherein, The difference between the HOMO energy level of the first sublayer and the HOMO energy level of the second sublayer is between 0.050 eV and 0.20 eV.

10. The solar cell according to any one of claims 1 to 9, wherein, L1 is selected from substituted or unsubstituted alkylene groups, and / or L2 is selected from substituted or unsubstituted alkylene groups.

11. The perovskite solar cell according to claim 10, wherein, The first compound or the second compound satisfies one or more of the following conditions: (1) The substituted or unsubstituted alkylene groups include any one of the C1 to C12 alkylene groups substituted or unsubstituted by halogens, oxyacid groups, C1 to C5 alkyl groups, C1 to C5 alkoxy groups, hexa- to deca-aryl groups, and penta- to deca-aryl heteroaryl groups; (2) The oxyacid group is selected from one or more of the following: phosphonic acid group, hypophosphite group, sulfonic acid group, carboxylic acid group, sulfinic acid group, boric acid group or silicate group.

12. The solar cell according to any one of claims 1 to 11, wherein, The first compound comprises (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid, and the second compound comprises (4-(7H-dibenzocarbazole-7-yl)butyl)phosphonic acid; or The first compound comprises (4-(3,6-dibromo-9H-carbazole-9-yl)butyl)phosphonic acid, and the second compound comprises (4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl)phosphonic acid; or The first compound comprises (4-(3,6-dibromo-9H-carbazole-9-yl)butyl)phosphonic acid, and the second compound comprises 4-(bis(4-(methylthio)phenyl)amino)phenethylphosphonic acid; or The first compound comprises (2-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid, and the second compound comprises (4-(7H-dibenzocarbazole-7-yl)butyl)phosphonic acid; or The first compound comprises (4-(3,6-diphenyl-9H-carbazole-9-yl)butyl)phosphonic acid, and the second compound comprises (4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl)phosphonic acid; or The first compound comprises (2-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid, and the second compound comprises 4-(4-(bis(4-(methylthio)phenyl)amino)phenyl)butyric acid.

13. The solar cell according to any one of claims 1 to 12, wherein, The thickness of the first sublayer is 1 nm to 10 nm, and / or The thickness of the second sublayer is 1 nm to 10 nm.

14. The solar cell according to any one of claims 1 to 13, 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 includes a first electrode, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer and a second electrode stacked in sequence.

15. A photovoltaic module comprising a solar cell according to any one of claims 1 to 14.

16. A power generation device comprising a solar cell according to any one of claims 1 to 14.

17. An electrical device comprising a solar cell according to any one of claims 1 to 14.

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