Compound, method of preparation thereof, use thereof, and perovskite solar cell comprising thereof

Abstract

A compound with the structure of formula (I) is provided, the substituents of which are defined in the description. Furthermore, this application provides a method of preparation and an application of the compound of formula (I), and relates particularly to a perovskite solar cell containing it. The advantage of using this compound as a void transport material is that it avoids the use of additives, thereby improving the photoelectric conversion efficiency and the stability of the battery.

Description

Compound, method of preparation thereof, use thereof, and perovskite solar cell comprising thereof Field This disclosure relates to the technical field of perovskite solar cells and, more particularly, to a new compound, a method of preparation and use thereof, and in particular to a perovskite solar cell containing the compound. Background With the continuous development of the global economy and society, the demand for energy in human society is increasing. However, due to overexploitation and growing environmental damage, traditional fossil fuels have struggled to meet the needs of the economy and society. Solar energy has attracted increasing attention due to its advantages of being renewable and pollution-free. Perovskite solar cells have broad development prospects due to their simple production process, low cost, and good photoelectric conversion efficiency. In perovskite solar cells, the gap transport layer is an important component that plays a key role in the photoelectric conversion efficiency of the cells. Currently, the gap transport layer typically includes a gap transport material (HTM) and additives, but this composition does not promote the long-term stable operation of perovskite solar cells. Therefore, further research and improvement of gap transport materials are still needed. CN 110 776 434 relates to a tetraarylbutadiene-based gap transport material. US 2015 / 311440 relates to a gap transport compound for an inorganic / organic hybrid perovskite solar cell. Summary This disclosure is made in view of the above topic, the aim of which is to provide a new compound having a deeper HOMO energy level and greater hole mobility, thereby improving the photoelectric conversion efficiency and stability of light-emitting devices, in particular perovskite solar cells. To achieve the above purpose, the present disclosure provides a compound having a structure of formula (I), where R1 is trivalent phenyl, optionally 1, 3, 5-benzenetriyl; R2 is a single bond, C2-C6 conjugated alkylene, or a 5-membered or 6-membered unsaturated ring group containing heteroatoms selected from O, S, or Se; and, optionally, R2 is a single bond, vinylidene, furylidene, thiophenylene, or selenophenylene. By using the trivalent R1 group and the divalent R2 group, four triphenylamine groups are connected to form a new structural arrangement. Therefore, its HOMO energy level is more compatible with the HOMO energy level of a perovskite layer, and the gap mobility is significantly improved. This allows for the elimination of additives in the preparation of a gap transport layer, further enhancing the photoelectric conversion efficiency and stability of light-emitting devices, particularly perovskite solar cells. In any embodiment, the compound of the present disclosure refers to a compound of formula (I-1), formula (I-2) or formula (I-3), These specific compounds are applied to the gap transport layer, which can further improve the stability and photoelectric conversion efficiency of light-emitting devices. In any embodiment, the compound of formula (I) of the present disclosure has a HOMO energy level of -5.05 eV to -5.30 eV, optionally from -5.1 eV to -5.2 eV, and a charge mobility of 1.0 × 10-4 cm2V-1s-1 to 8.0 × 10-4 cm2V-1s-1, optionally from 2.0 × 10-4 cm2V-1s-1 to 6.0 × 10-4 cm2V-1s-1. A second aspect of this disclosure provides a method for preparing a compound of formula (I). The method includes the following steps: Step 1: Preparation of a compound of formula (II): 4,4'-dimethoxydiphenylamine and an iodobenzene dibromide of formula (1) undergo a coupling reaction to form an intermediate (2); the intermediate (2) and 4-borate-4',4'-dimethoxytriphenylamine of formula (3) undergo a coupling reaction to generate an intermediate (4); and the intermediate (4) and 2-(4-bromophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane of formula (5) undergo a coupling reaction to obtain the compound of formula (II); Step 2: Preparation of a compound of formula (III): 4,4'-dimethoxydiphenylamine and a compound of formula (6) undergo a coupling reaction to form an intermediate (7), and the intermediate (7) and p-methoxyaniline of formula (8) undergo a coupling reaction to generate the compound of formula (III); and Step 3: Preparation of a compound of formula (I): The compound of formula (II) and the compound of formula (III) undergo a coupling reaction in the presence of a palladium catalyst and an alkali to obtain the compound of formula (I). The above preparation method has the advantages of high yield and low cost. A third aspect of this disclosure provides uses of the compound of formula (I) described in the first aspect of this disclosure and of the compound of formula (I) obtained according to the preparation method described in the second aspect of this disclosure, and the use of the compound of formula (I) as a void transport material in a light-emitting device. The light-emitting device includes an organic electroluminescent device and a perovskite solar cell. As a result, the light-emitting device with improved photoelectric conversion efficiency and stability is obtained. In any embodiment, the perovskite solar cell of the present disclosure includes a conductive glass, an electron transport layer, a perovskite layer, a hole transport layer, and an ethanol electrode. The hole transport layer includes the compound of formula (I) described in the first aspect of the present disclosure or the compound of formula (I) obtained according to the preparation method described in the second aspect of the present disclosure. As a result, a perovskite solar cell with good photoelectric conversion efficiency and stability is obtained. In any embodiment of the perovskite solar cell of this disclosure, the void transport layer contains no additives. Additives are selected from lithium salts, cobalt salts, or cosolvents, including one or more of lithium bis(trifluoromethane)sulfonimide (Li-TFSI), cobalt(III) bistrifluoromethanesulfonimide (FK209, Co(III) TFSI), and 4-tert-butylpyridine (tBP). Therefore, problems caused by the use of additives can be avoided, and the photoelectric conversion efficiency and stability of the perovskite cell can be further improved. In any embodiment, in the perovskite solar cell of the present disclosure, the hole transport layer has a HOMO energy level of -5.05 eV to -5.30 eV, optionally from -5.1 eV to -5.2 eV; and the perovskite layer has an upper valence band energy level of -5.30 eV to -5.60 eV, optionally from -5.30 eV to -5.50 eV. In any embodiment of the perovskite solar cell of the present disclosure, the HOMO energy level of the gap transport layer is greater than the upper energy level of the valence band of the perovskite layer, with an energy level difference of 0.35 eV to 0.05 eV, optionally from 0.3 eV to 0.2 eV. In any embodiment of the perovskite solar cell of the present disclosure, the thickness of the gap transport layer is from 5 nm to 100 nm, optionally from 30 nm to 80 nm. When the gap transport layer includes the compound of formula (I) of the present disclosure, and its thickness is within the above range, the gap transport layer can not only perform the function of extracting and transporting gaps, but also helps to block the entry of external water and oxygen, thereby improving the long-term operational stability of the perovskite solar cell. In any embodiment, a perovskite solar cell preparation method of the present disclosure includes a gap transport layer preparation step: The compound of formula (I) described in the first aspect of this disclosure and the compound of formula (I) obtained according to the preparation method described in the second aspect of this disclosure are dissolved in an organic solvent to prepare a void transport material solution; the void transport material solution is then coated onto the surface of the perovskite layer and the solvent is removed to obtain the void transport layer; When the perovskite solar cell is a forward perovskite solar cell, the concentration of the compound of formula (I) in the gap transport material solution is 20-100 mg / ml; when the perovskite solar cell is an inverted perovskite solar cell, the concentration of the compound of formula (I) in the gap transport material solution is 1-50 mg / ml; and The organic solvent is toluene, chlorobenzene, or dichloromethane. The compound of formula (I) provided in this disclosure has a HOMO energy level that matches the energy level of the perovskite layer, and high gap mobility, and can avoid the use of additives when applied to the gap transport layer, thereby obtaining a perovskite solar cell with significantly improved photoelectric conversion efficiency and stability. Brief description of the drawings Figure 1 is a schematic structural diagram of a forward perovskite solar cell in an embodiment of the present disclosure. 1-Conductive glass; 2-Electron transport layer; 3-Perovskite layer; 4-Hole transport layer; 5-Metallic electrode; and 6-Incident light. Description of achievements The following are detailed descriptions, with reference to the accompanying drawings, of embodiments of a compound of formula (I) of this disclosure and of a perovskite solar cell comprising the compound of formula (I). However, there will be instances where unnecessary details are omitted. For example, detailed descriptions of well-known matters and duplicate statements of the same actual structure are omitted. This is to prevent the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following descriptions are provided for the full understanding of this disclosure by those skilled in the art and are not intended to limit the subject matter of the claims. The "range" disclosed herein is defined by a lower and an upper bound, and a given range is defined by selecting a lower and an upper bound. The chosen lower and upper bounds define the limits of a particular range. The range thus defined may or may not include an extreme value and can be combined arbitrarily. That is, any lower bound can be combined with any upper bound to form a range. For example, if the ranges 60–120 and 80–110 are specified for a particular parameter, it is also reasonable to expect the ranges 60–110 and 80–120. Furthermore, if the minimum values ​​1 and 2 of the range are listed, and if the maximum values ​​3, 4, and 5 of the range are listed, then all the following ranges 1–3, 1–4, 1–5, 2–3, 2–4, and 2–6 can be expected.In this disclosure, unless otherwise specified, the range of values ​​"ab" is shorthand for any combination of real numbers aab, where a and b are both real numbers. For example, the range of values ​​"0-5" represents that all real numbers between 0 and 5 have been listed herein, and "0-5" is only shorthand for combinations of these values. Furthermore, when an integer 2 is described for a parameter, it is equivalent to disclosing that this parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12, etc. Unless otherwise specified, all embodiments of this disclosure and optional embodiments may be combined to form a new technical solution. Unless otherwise specified, all technical features in this disclosure and optional technical features may be combined to form a new technical solution. Unless otherwise specified, all steps in this disclosure may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, and may also include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), may also include steps (a), (c), and (b), may also include steps (c), (a), and (b), and so forth. Unless otherwise specified, "include" and "comply" as used in this disclosure can be either open-ended or closed-ended. For example, "include" and "comply" may mean that other components not listed may also be included or comprised, or that only the listed components may be included or comprised. Unless otherwise specified, the term "or" is inclusive in this disclosure. For example, the expression "A or B" means "A, B, or both A and B." More specifically, any of the following conditions satisfies the "A or B" condition: A is true (or present) and B is false (or absent); A is false (or absent) and B is true (or present); or both A and B are true (or present). In perovskite solar cells, the gap transport layer material is a crucial component of efficient perovskite solar cells due to its functions in interface optimization, energy level matching regulation, and other areas. Therefore, the ideal gap transport layer material should possess the following properties: high gap mobility, with a highest occupied molecular orbital (HOMO) energy level ranging from -5.1 eV to -5.3 eV; and high thermodynamic stability, good solubility and film-forming properties, as well as hydrophobicity, to better protect the perovskite layer and enhance cell stability. Currently, the most commonly used gap transport layer material is 2,2',7,7'-tetrakis(N,N-bis(4-methoxyphenyl)amino]-9,9'-spiro-OMeTAD, whose structure is shown in formula (A) below.However, the void transport layer material has low void mobility and therefore must be applied to the void transport layer along with additives including lithium bis(trifluoromethane)sulfonimide (Li-TFSI) and 4-tert-butylpyridine (TBP) to improve void mobility. However, these additives can cause degradation of the perovskite layer material, which does not favor the long-term operational stability of a device. By analyzing the relationship between the structure and properties of the molecules in the gap transport layer material, the inventors discovered that the connection mode of the triphenylamine groups in the molecular structure has a significant impact on its properties. By changing the connection mode and relative position of the triphenylamine groups in the molecule, a new compound is obtained, as disclosed herein, that has a deeper HOMO energy level and greater gap mobility, thereby eliminating the need for additives in the preparation of the gap transport layer and improving the stability and photoelectric conversion efficiency of the device. A first aspect of the present disclosure provides a compound having a structure of formula (I), where R1 is trivalent phenyl, optionally 1, 3, 5-benzenetriyl; R2 is a single bond, C2-C6 conjugated alkylene, or a 5-membered or 6-membered unsaturated ring group containing heteroatoms selected from O, S, or Se; and, optionally, R2 is a single bond, vinylidene, furylidene, thiophenylene, or selenophenylene. In this disclosure, the term "trivalent phenyl," as used, refers to a trivalent benzene group generated by the loss of any three hydrogen atoms from a benzene ring. The any three hydrogen atoms can be hydrogen atoms bonded to any three carbon atoms in any position on the benzene ring. Examples of trivalent phenyl are 1,3,5-benzenetriyl of formula (a), 1,2,4-benzenetriyl of formula (b), and 1,2,3-benzenetriyl of formula (c). Optionally, R1 is 1, 3, 5-benzenetriyl of formula (a). In this disclosure, the term "C2-C6 conjugated alkenylene," as used, refers to an olefin having a structure in which single and double bonds alternate, e.g., -CH=CH-CH=CH-. Examples include, but are not limited to, vinylene, butadienyl, and hexatrienyl -CH=CH-CH=CH-CH=CH-. In this disclosure, the terms "furylidene, thiophenylene, or selenophenylene" refer to divalent groups generated by the loss of any two hydrogen atoms from the corresponding compounds (furan, thiophene, and selenium). Any two hydrogen atoms can be any two hydrogen atoms attached to any carbon atom of the corresponding compound. Examples include, but are not limited to, 2,5-furylidene, 2,5-thiophenylene, and 2,5-selenophenylene, which have the following respective structural formulas: In the compound of formula (I) of the present disclosure, four triphenylamine groups are linked together by two connecting groups R1 and R2, forming a novel structural arrangement between the triphenylamine groups. R1 connects three triphenylamine groups, and R2 connects two triphenylamine groups. This connection mode not only regulates the molecular energy level, ensuring that the HOMO energy level matches the HOMO energy level of the perovskite layer, but also enhances the mobility of the gaps in the gap transport layer, thereby eliminating the need for additives and further improving the photoelectric conversion efficiency and stability of light-emitting devices, particularly perovskite solar cells. In some embodiments, the compound of the present disclosure is a compound of formula (I-1), formula (I-2) or formula (I-3), These compounds have high hole mobility and a HOMO energy level that matches the upper valence band energy level of the perovskite layer, as well as hydrophobicity, to better protect the perovskite layer and improve the stability and photoelectric conversion efficiency of light-emitting devices. In some embodiments, the compound of formula (I) of the present disclosure has a HOMO energy level of -5.05 eV to -5.30 eV, optionally from -5.1 eV to -5.2 eV, and a charge mobility of 1.0 × 10⁻⁴ cm²V⁻¹s⁻¹ to 8.0 × 10⁻⁴ cm²V⁻¹s⁻¹, optionally from 2.0 × 10⁻⁴ cm²V⁻¹s⁻¹ to 6.0 × 10⁻⁴ cm²V⁻¹s⁻¹. Therefore, the compound can be applied to light-emitting devices, particularly perovskite solar cells, as a hole transport material, thereby improving the photoelectric conversion efficiency and device stability. In the present disclosure, the HOMO energy level of the compound of formula (I) is determined using UPS ultraviolet photoelectron spectroscopy (AXIS ULTRA DLD of Kratos Company), for example, using a method of determining the HOMO energy level described in the examples. In this disclosure, the compound of formula (I-1) has a HOMO energy level of -5.2 eV, the compound of formula (I-2) has a HOMO energy level of -5.1 eV, and the compound of formula (I-3) has a HOMO energy level of -5.2 eV. In this disclosure, the hole mobility of the compound of formula (I) is determined by a space charge limiting current (SCLC) method, e.g., using a hole mobility determination method described in the examples. In this disclosure, the compound of formula (I-1) has a hole mobility of 3.5 × 10-4 cm2V-1s-1, the compound of formula (I-2) has a hole mobility of 5.0 × 10-4 cm2V-1s-1, and the compound of formula (I-3) has a hole mobility of 2.0 × 10-4 cm2V-1s-1. A second aspect of this disclosure provides a method for preparing the compound of formula (I). The method includes the following steps: Step 1: Preparation of a compound of formula (II): 4,4'-dimethoxydiphenylamine and an iodobenzene dibromide of formula (1) undergo a coupling reaction to form an intermediate (2); the intermediate (2) and 4-borate-4',4'-dimethoxytriphenylamine of formula (3) undergo a coupling reaction to generate an intermediate (4); and the intermediate (4) and 2-(4-bromophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane of formula (5) undergo a coupling reaction to obtain the compound of formula (II); Step 2: Preparation of a compound of formula (III): 4,4'-dimethoxydiphenylamine and a compound of formula (6) undergo a coupling reaction to form an intermediate (7), and the intermediate (7) and p-methoxyaniline of formula (8) undergo a coupling reaction to generate the compound of formula (III); and Step 3: Preparation of a compound of formula (I): The compound of formula (II) and the compound of formula (III) undergo a coupling reaction in the presence of a palladium catalyst and an alkali to obtain the compound of formula (I). The compound of formula (I) prepared by the above method has the advantages of cheap raw material price, high yield and low cost. Synthesis of intermediate (2): In an argon atmosphere, with toluene as the solvent, 4,4'-dimethoxydiphenylamine and iodobenzene dibromide of formula (1) are heated and refluxed in the presence of a complex (such as PdCl(3-C3H5)2) and a strong base (cesium carbonate) to generate intermediate (2). The molar ratio of 4,4'-dimethoxydiphenylamine to the compound of formula (1) to the complex to the strong base is 1:(1-1.2):(0.01-0.015):(0.02-0.025):(1.5-1.8). Synthesis of intermediate (4): In an argon atmosphere, with tetrahydrofuran and water as solvents, intermediate (2) and 4-borate-4',4'-dimethoxytriphenylamine of formula (3) are heated and refluxed in the presence of a catalyst (such as Pd(PPh3)4) and a strong base (such as sodium hydroxide) to generate intermediate (4). The molar ratio of intermediate (2) to borate compound of formula (3) to catalyst to strong base is 1: (1.08-1.2) : (0.025-0.035) : (2.95-3.05). Synthesis of the compound of formula (II): In an argon atmosphere, at 40-60 °C, with ethanol and water as solvents, intermediate (4) and 2-(4-bromophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane are reacted in the presence of a strong base (e.g., potassium carbonate) and a catalyst (e.g., tris(dibenzylideneacetone)dipalladium Pd2(dba)3) to generate the compound of formula (II). The molar ratio of intermediate (4) to borate compound of formula (5) to strong base to catalyst is 1:(1.0-1.25):(1.8-2.2):(0.01-0.5). Synthesis of intermediate (7): In an argon atmosphere, at 105-120 °C, with toluene as solvent, 4,4'-dimethoxydiphenylamine and the compound of formula (6) are reacted in the presence of a catalyst (e.g., Pd2(dba)3), a strong base (e.g., cesium carbonate), and a ligand (e.g., tri-tert-butylphosphine) to generate intermediate (7). The molar ratio of the compound of formula (6) to 4,4'-dimethoxydiphenylamine to the catalyst to the strong base is 1: (1-1.25): (0.015-0.03): (1.5-2.2). Synthesis of the compound of formula (III): In an argon atmosphere, at 105-120 °C, with toluene as the solvent, intermediate (7) and p-methoxyaniline of formula (8) are reacted in the presence of a catalyst (e.g., Pd2(dba)3), a strong base (e.g., cesium carbonate), and a ligand (e.g., tri-tert-butylphosphine) to generate the compound of formula (III). The molar ratio of intermediate (7) to p-methoxyaniline of formula (8) to the catalyst to the strong base is 1: (1-1.25): (0.015-0.03): (1.5-2.2). Synthesis of the compound of formula (I): In an argon atmosphere, at 105-120 °C, with toluene as the solvent, the compound of formula (II) and the compound of formula (III) are reacted in the presence of a catalyst (e.g., Pd2(dba)3), a strong base (e.g., cesium carbonate), and a ligand (e.g., tri-tert-butylphosphine) to generate the compound of formula (I). The molar ratio of the compound of formula (II) to the compound of formula (III) to the catalyst to the strong base is 1:(1-1.2):(0.15-0.3):(18-22). In the above reactions, the catalyst is a palladium catalyst, including, but not limited to, Pd(PPh3)4, Pd2(dba)3, or PdAc2. In the reactions above, the strong base includes, but is not limited to, sodium hydroxide, cesium carbonate, or potassium carbonate. In the above reactions, the solvent includes, but is not limited to, one or more of toluene, ethanol, tetrahydrofuran, or water. The compound of formula (6) can be purchased commercially or prepared according to the methods provided by the examples. A third aspect of this disclosure provides uses of the compound of formula (I) described in the first aspect of this disclosure and of the compound of formula (I) obtained according to the preparation method described in the second aspect of this disclosure, and the use of the compound of formula (I) as a void transport material in a light-emitting device. The light-emitting device includes an organic electroluminescent device and a perovskite solar cell. Therefore, since the compound of formula (I) of the present disclosure has a deeper HOMO energy level and greater hole mobility, it can be applied to light-emitting devices to improve photoelectric conversion efficiency and device stability. This disclosure provides a perovskite solar cell comprising a conductive glass, an electron transport layer, a perovskite layer, a hole transport layer, and a metal electrode. The hole transport layer comprises either the compound of formula (I) provided in the first aspect of this disclosure or the compound of formula (I) obtained according to the preparation method provided in the second aspect of this disclosure. The resulting perovskite solar cell exhibits good photoelectric conversion efficiency and stability. [Perovskite solar cells] Perovskite solar cells can be divided into direct and inverted types based on the difference in their incidence surface. A direct perovskite solar cell can sequentially include, in its structure, a conductive glass layer, an electron transport layer, a perovskite layer, a hole transport layer, and a metal electrode. That is, the incident light passes sequentially through the conductive glass, the electron transport layer, the perovskite layer, the hole transport layer, and the metal electrode. An inverted perovskite solar cell can also sequentially include the same layers: conductive glass, a hole transport layer, a perovskite layer, an electron transport layer, and a metal electrode. Similarly, the incident light passes sequentially through the conductive glass, the hole transport layer, the perovskite layer, the electron transport layer, and the metal electrode. Figure 1 is a schematic diagram of the structure of a forward perovskite solar cell in an embodiment of the present disclosure. The forward perovskite solar cell includes sequentially, from top to bottom, a conductive glass, an electron transport layer, a perovskite layer, a hole transport layer, and a metal electrode, with incident light entering from the top conductive glass. The following describes the structural components of the perovskite solar cell of this disclosure, but this disclosure is not limited to them. Conductive glass Conductive glass typically has some degree of transparency. Generally, clear conductive glass is used. Conductive glass usually consists of a glass substrate and a conductive oxide film (TCO) layer. Commonly used TCOs include, but are not limited to, the following materials: fluorine-doped tin oxide (FTO), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), and indium zinc oxide (IZO). Conductive glass is generally any conductive glass used in the art. Conductive glass is commercially available. Conductive glass must be cleaned before use, i.e., it is cleaned by ultrasound with a cleaning agent, deionized water, ethanol, etc. Electron transport layer The materials of the electron transport layer can be materials commonly used in the technique, including, but not limited to: methyl[6,6]phenylC61 butyrate (PC61BM), methyl[6,6]phenylC71 butyrate (PC71BM), C60 fullerene (C60), C70 fullerene (C70), tin dioxide (SnO2), zinc oxide (ZnO) or titanium dioxide (TiO2), and derivatives of the above substances, materials obtained by doping or passivation, etc. The electron transport layer can be prepared by conventional methods in the art, or by the following method: the electron transport layer material is dissolved in an organic solvent (e.g., chlorobenzene, dichlorobenzene, toluene, or xylene) to prepare a solution of the electron transport layer material with a concentration range of 5-50 mg / ml.Next, the solution is coated onto the surface of the conductive glass or perovskite layer by spin coating using a homogenizer at a rotation speed of 500-5000 rpm and a spin coating time of 5-50 seconds, and then annealed at an annealing temperature of 80-150 °C for 5-60 min, to obtain the electron transport layer. The thickness of the electron transport layer can be any thickness used in the technique. Optionally, the electron transport layer is 40 nm to 100 nm thick. Perovskite layer The chemical formula of the perovskite layer conforms to ABX3 or A2CDX6, where A is an inorganic or organic or mixed organic-inorganic cation, which can be at least one of MA, FA, Cs; B is an inorganic or organic or mixed organic-inorganic cation, which can be at least one of Pb and Sn; C is an inorganic or organic or mixed organic-inorganic cation, commonly Ag+; D is an inorganic or organic or mixed organic-inorganic cation, which can be at least one of bismuth cation Bi3+, antimony cation Sb3+ and indium cation In3+; and X is an inorganic or organic or mixed organic-inorganic anion, which can be at least one of Br or I. The perovskite layer has a band gap of 1.20-2.30 eV. The perovskite layer has an upper valence band energy level (the upper valence band energy level refers to the highest energy level that electrons can occupy in the material when the temperature is 0 K) of -5.30 eV to -5.60 eV, optionally from -5.30 eV to -5.50 eV. In the present disclosure, the chemical formula of perovskite is (Cs0, 05FA0, 93MA0, 02) Pb (I0, 98Br0, 02) 3, and perovskite has an upper valence band energy level of -5, 40 eV. The perovskite layer can be prepared by conventional technical means in the art, or by the following method (taking as an example a perovskite solar cell with a direct structure): perovskite precursor materials such as lead iodide (PbI2), formamidine iodide (FAI), cesium iodide (CsI), methylammonium bromide (MABr) or lead bromide (PbBr2) are weighed and dissolved in a solvent (e.g., dimethylformamide (DMF) or dimethyl sulfoxide (DMSO)), stirred well and filtered to obtain a supernatant; the supernatant coats the electron transport layer or hole transport layer prepared by spin coating using a homogenizer at a rotation speed of 500-5000 rpm and a spin coating time of 5-50 seconds; After coating, annealing is carried out at an annealing temperature of 80-150 °C for 0-60 minutes;and the perovskite layer is obtained after annealing. The perovskite layer thickness can be any thickness used in the technique. Optionally, the perovskite layer has a thickness of 200 nm to 1000 nm. Void transport layer The void transport layer includes a compound of formula (I) described in the first aspect of this disclosure or a compound of formula (I) prepared according to the method described in the second aspect of this disclosure: where R1 is trivalent phenyl, optionally 1, 3, 5-benzenetriyl; R2 is a single bond, C2-C6 conjugated alkylene, or a 5-membered or 6-membered unsaturated ring group containing heteroatoms selected from O, S, or Se; and, optionally, R2 is a single bond, vinylidene, furylidene, thiophenylene, or selenophenylene. In some embodiments, the void transport layer of the present disclosure does not contain additives, the additives being selected from lithium salts, cobalt salts or cosolvents, including one or more of lithium salt of bis(trifluoromethane)sulfonimide (Li-TFSI), cobalt(III) salt of bis-trifluoromethanesulfonimide (FK209, Co(III)TFSI) and 4-tert-butylpyridine (tBP). Currently, the most commonly used hole transport material is Spiro-OMeTAD (shown in formula (A) above). When applied to the hole transport layer, additives such as lithium salts and tBP are often required to increase hole mobility. However, the lithium salt will penetrate the perovskite layer, eventually leading to degradation of the perovskite layer material, which does not favor the long-term operational stability of perovskite solar cell devices. Through a great deal of research and practice, the authors of the invention have designed the compound of formula (I) of the present disclosure, which has greater void mobility and has a HOMO energy level that perfectly matches the perovskite layer, so that the use of additives can be avoided to further improve the photoelectric conversion efficiency and stability of the perovskite cells. In this disclosure, the gap transport layer may also be composed of a compound of formula (I) described in this disclosure or a compound of formula (I) prepared according to the method described in this disclosure, excluding any other gap transport material that may be used for perovskite solar cells. Optionally, the compound of formula (I) is a compound of formula (I-1), formula (I-2) or formula (I-3): In some embodiments, in the perovskite solar cell of the present disclosure, the HOMO energy level of the hole transport layer is from -5.05 eV to -5.30 eV, optionally from -5.1 eV to -5.2 eV; and the upper energy level of the valence band of the perovskite layer is from -5.30 eV to -5.60 eV, optionally from -5.30 eV to -5.50 eV. Optionally, the HOMO energy level of the hole transport layer is higher than the upper energy level of the valence band of the perovskite layer, with an energy level difference of 0.3 eV to 0.05 eV, optionally from 0.3 eV to 0.2 eV. In the perovskite solar cell of the present disclosure, the gap transport material of the gap transport layer is a compound of formula (I) of the present disclosure, and this compound has a HOMO energy level of -5.05 eV to -5.30 eV, optionally from -5.1 eV to -5.2 eV, and a charge mobility of 1.0 × 10-4 cm2V-1s-1 to 8.0 × 10-4 cm2V-1s-1, optionally from 2.0 × 10-4 cm2V-1s-1 to 6.0 × 10-4 cm2V-1s-1. In one specific embodiment, the hole transport layer includes or consists of a compound of formula (I-1) of this disclosure. The hole transport layer has a HOMO energy level of -5.2 eV and a hole mobility of 3.5 × 10⁻⁴ cm²V⁻¹s⁻¹. In one specific embodiment, the hole transport layer includes or consists of a compound of formula (I-2) of this disclosure. The hole transport layer has a HOMO energy level of -5.1 eV and a hole mobility of 5.0 × 10⁻⁴ cm²V⁻¹s⁻¹. In one specific embodiment, the hole transport layer includes or consists of a compound of formula (I-3) of this disclosure. The hole transport layer has a HOMO energy level of -5.2 eV and a hole mobility of 2.0 × 10-4 cm2V-1s-1. The compound of formula (I) in this disclosure has strong hydrophobicity. When the void transport layer is within the above thickness range, it can not only perform the function of extracting and transporting voids, but also helps to block the entry of external water and oxygen, thereby helping to improve the long-term operational stability of perovskite solar cells. In some embodiments, in the perovskite solar cell of the present disclosure, the hole transport layer has a thickness of 5 nm to 100 nm, optionally from 30 nm to 80 nm. The most intense absorption peak of the compound of formula (I) of the present disclosure is less than 400 nm, indicating that the compound of formula (I) and the gap transport layer that includes it will not absorb visible light. The void transport layer can be prepared by conventional methods in the art, including, but not limited to, a sun method, a knife coating method, and a slot coating method. In some embodiments of the perovskite solar cell of the present disclosure, the hole transport layer is prepared by the following method: The compound of formula (I) described in the first aspect of this disclosure and the compound of formula (I) obtained according to the preparation method described in the second aspect of this disclosure are dissolved in an organic solvent to prepare a gap transport material solution; and then the gap transport material solution is coated onto the surface of the perovskite layer or conductive glass and the solvent is removed to obtain the gap transport layer. When the perovskite solar cell is a forward perovskite solar cell, the concentration of the compound of formula (I) in the gap transport material solution is 20-100 mg / ml; when the perovskite solar cell is an inverted perovskite solar cell, the concentration of the compound of formula (I) in the gap transport material solution is 1-50 mg / ml; and The organic solvent is toluene, chlorobenzene, or dichloromethane. Optionally, the coating can be applied by spin coating using a homogenizer. The spin speed is 500–5000 rpm and the spin coating time is 5–50 seconds. After spin coating, the solvent can be removed by annealing. For example, when annealing is used, the annealing temperature is 80–400 °C, the annealing time is 0–120 min, and the void transport layer is obtained after annealing. Metallic electrode The metallic electrode can be any electrode used in the technique. Optionally, the metallic electrode is an organic, inorganic, or mixed organic-inorganic conductive material, including, but not limited to, the following materials: Ag, Cu, C, Au, Al. The metallic electrode can be prepared by evaporation. The thickness of the metal electrode can be any thickness used in the technique. Optionally, the thickness of the metal electrode is 10–200 nm. [Perovskite solar cell preparation method] In some embodiments, the perovskite solar cell described in this disclosure is a direct perovskite solar cell. The direct perovskite solar cell preparation method includes the following steps: Step 1: Prepare a void transport material of formula (I) of the present disclosure; Step 2: Etch and clean a transparent conductive glass substrate, and blow dry for later use; Step 3: Prepare an electron transport layer on the conductive glass; Step 4: Prepare a perovskite layer over the electron transport layer; Step 5: Prepare a solution of the void transport material of formula (I) of this disclosure for further use; Step 6: Prepare a void transport layer on top of the perovskite layer; and Step 7: Prepare a metal electrode layer over the void transport layer and perform an edge cleaning test. The method for preparing the inverted perovskite solar cell includes the following steps: Step 1: Prepare a void transport material of formula (I) of the present disclosure; Step 2: etch and clean a transparent conductive glass substrate, and blow dry for later use; Step 3: prepare a solution of the gap transport material of formula (I) of the present disclosure for later use; Step 4: Prepare a void transport layer on the conductive glass; Step 5: Prepare a perovskite layer on top of the void transport layer; Step 6: Prepare an electron transport layer on the perovskite layer; and Step 7: Prepare a metallic electrode layer over the electron transport layer, and perform an edge cleaning test. The specific operations of the respective stages above are described above or prepared in accordance with the examples. It should be understood that, although this disclosure provides the perovskite solar cell that includes the compound of formula (I) in some embodiments, this disclosure is not limited to it. All light-emitting devices that include the compound of formula (I) of this disclosure (for example, including, but not limited to, a perovskite solar cell or an OLED device) and methods of preparing light-emitting devices are all within the scope of this disclosure. Examples The following describes the examples in this disclosure. The examples described below are illustrative and are intended only to explain this disclosure, rather than to be interpreted as limitations of this disclosure. If no specific techniques or conditions are indicated in the examples, they should be carried out in accordance with the techniques or conditions described in the literature on the technique or in accordance with the product specifications. Reagents or instruments used that are not marked with trademarks are conventional products available on the market. I. Example of preparation Example 1: Preparation of (5'-(4-(bis(4-ethylphenyl)amino)phenyl)-N4-(4'-(bis(4-methoxyphenyl)amino)-[1,1'-biphenyl]-4-yl)-N4,N4',N4'-tris(4-methoxyphenyl)-[1,1':3',1'-triphenyl]-4, 4'-diamine) (compound of formula (I-1)) Step S1: Synthesis of 3',5'-dibromo-N,N-bis(4-methoxyphenyl)-[1,1'-biphenyl]-4-amine 4,4'-Dimethoxydiphenylamine (40 mmol, 9.17 g), 3,5-dibromo-4'-iodo-1,1'-biphenyl (40 mmol, 17.52 g), allyl palladium(II) chloride dimer complex PdCl(3-C3H5)2 (0.4 mmol, purchased from Bide Pharmatech, CAS: 12012-95-2), cesium carbonate (0.8 mmol), and succinic acid (60 mmol) were added to a Schlenk tube. A vacuum was then applied to the Schlenk tube, and argon was introduced. This operation was repeated three times to maintain the Schlenk tube filled with argon. 180 mL of toluene was then added to the mixture in the Schlenk tube under argon. The Schlenk tube was placed in an oil bath at 115 °C and the reaction mixture was stirred under reflux for 20 h. After the reaction was complete, the mixture was extracted with saturated saline solution (50 mL each time, 3 times in total). The organic layer was dried with anhydrous MgSO4, filtered, and evaporated to dryness under reduced pressure to obtain a crude product.The crude product was separated by column chromatography (the stationary phase was 200-300 mesh silica gel and the mobile phase was ethyl acetate:n-hexane = 1:4, volumetric ratio) to obtain 12.25 g of the product 3', 5'-dibromo-N, N-bis(4-methoxyphenyl)-[1, 1'-biphenyl]-4-amine with a yield of 56.8%. 1H NMR (CDCl3, 400 MHz): 3.75 (6H, s), 6.71 (4H, ddd, J = 8.7, 2, 7, 0.5 Hz), 7.02-7.23 (5H, 7.09 (ddd, J = 8.7, 1.3, 0.5 Hz) , 7, 17 (t, J = 1, 8 Hz) ) , 7, 26-7, 56 (6H, 7, 33 (ddd, J = 8, 9, 1, 5, 0, 5 Hz) , 7, 45 (ddd, J = 8, 9, 1, 5, 0, 5 Hz) , 7, 51 (t, J = 1.8 Hz) ) . Step S2: Synthesis of 5'-bromo-N4, N4', N4', N4'-tetrakis(4-methoxyphenyl)-[1, 1':3', 1'-triphenyl]-4, 4'-diamine A THF tetrahydrofuran solution (80 mL) of 3',5'-dibromo-N,N-bis(4-ethylphenyl)-[1,1'-biphenyl]-4-amine (12.19 g, 22.6 mmol) prepared in step S1, 4-borate-4',4'-dimethoxytriphenylamine (10.70 g, 24. 8 mmol, purchased from Bide Pharmatech, CAS: 875667-84-8), Pd(PPh3)4 (0.78 g, 0.7 mmol), NaOH (2.71 g, 67.7 mmol) and water (40 ml) were added to a round bottom flask. The reaction mixture was stirred for 24 h at 110 °C and extracted with dichloromethane (50 mL each time, 4 times). The organic layer was dried with anhydrous MgSO4, filtered, and evaporated to dryness under reduced pressure to obtain a crude product. The crude product was separated by column chromatography (stationary phase was 200–300 mesh silica gel and mobile phase was dichloromethane:n-hexane = 1:5, volumetric ratio) to obtain 12.03 g of the product 5'-bromo-N4,N4,N4',N4'-tetrakis(4-methoxyphenyl)-[1,1':3',1'-triphenyl]-4,4'-diamine in a yield of 69.7%. 1H NMR (CDCl3, 400 MHz) : 3, 75 (12H, s) , 6, 71 (8H, ddd, J = 8, 7, 2, 7, 0, 5 Hz) , 7, 09 (8H, ddd, J = 8, 7, 1, 3, 0, 5 Hz) , 7, 27-7, 48 (10H, 7, 33 (ddd, J = 8, 9, 1, 5, 0, 5 Hz) , 7, 38 (ddd, J = 8, 9, 1, 5, 0, 5 Hz) , 7, 42 (t, J = 1, 8 Hz) ) , 8, 05 (1H, t, J = 1, 8 Hz) . Step S3: Synthesis of 5'- (4-bromophenyl) -N4, N4, N4', N4'-tetraquis (4-methoxiphenyl) -[1, 1':3', 1'-triphenyl]-4, 4'-diamina 5'-Bromo-N4,N4,N4',N4'-tetrakis(4-methoxyphenyl)-[1,1':3',1'-triphenyl]-4,4'-diamine (8.39 g, 10 mmol) prepared in step S2, 2-(4-bromophenyl)-4,4,5,5-tetramethyl-1,3, 2-dioxaborolane (3.4 g, 12 mmol), purchased from Bide Pharmatech, CAS: 68716-49-4), potassium carbonate (20 mmol), and tris(dibenzylideneacetone)dipalladium(O)Pd2(dba)3 (purchased from Bide Pharmatech, CAS: 60748-47-2) (0.2 mmol), tri-tert-butylphosphine (0.8 mmol) and a mixture (30 mL) of EtOH and H2O in a 1:1 volumetric ratio were added to a Schlenk tube. A vacuum was then applied to the Schlenk tube and argon was introduced, and this operation was repeated 3 times to keep the Schlenk tube filled with argon. In argon, the reaction mixture was stirred for 2.5 h at 50 °C. After the reaction was complete, the mixture was cooled to room temperature and extracted with CH2Cl2 (50 mL each time, 4 times in total).The organic layer was dried with anhydrous MgSO4, filtered, and evaporated to dryness under reduced pressure to obtain a crude product. The crude product was separated by column chromatography (the stationary phase was 200-300 mesh silica gel and the mobile phase was dichloromethane:n-hexane = 1:4, volumetric ratio) to obtain 5.18 g of the product 5'-(4-bromophenyl)-N4,N4,N4',N4'-tetrakis(4-methoxyphenyl)-[1,1':3',1'-triphenyl]-4,4'-diamine in a yield of 61.8%. 1H NMR (CDCl3, 400 MHz): 3.75 (12H, s), 6.71 (8H, ddd, J = 8.7, 2.7, 0.5 Hz), 7.08 (8H, ddd, J = 8.7, 1.3, 0.5 Hz), 7.28-7, 56 (12H, 7, 34 (ddd, J = 8, 9, 1, 5, 0, 5 Hz) , 7, 36 (ddd, J = 8, 9, 1, 6, 0, 5 Hz) , 7, 44 (ddd, J = 8, 7, 1, 5, 0, 5 Hz) , 7, 50 (ddd, J = 8, 7, 1, 6, 0.5 Hz), 7, 97-8, 08 (3H, 8, 03 (t, J = 1, 9 Hz), 8, 03 (t, J = 1, 9 Hz)). Etapa S4: Síntesis de N4, N4-bis (4-metoxifenil) -[1, 1'-bifenil]-4-amina. 4,4'-Dibromobiphenyl (20 mmol), 4,4-dimethoxydiphenylamine (24 mmol), Pd2(dba)3 (0.4 mmol), Cs2CO3 (40 mmol), tri-tert-butylphosphine (1.6 mmol), and 200 mL of toluene were sequentially added to a Schlenk tube. A vacuum was then applied to the Schlenk tube, and argon was introduced. This operation was repeated three times to maintain the Schlenk tube filled with argon. The reaction mixture was stirred in argon for 24 h at 110 °C. After the reaction was complete, the mixture was extracted with saturated saline solution (50 mL each time, four times in total). The organic layer was dried with anhydrous MgSO4, filtered and evaporated to dryness under reduced pressure to obtain a crude product.The crude product was separated by column chromatography (stationary phase was 200-300 mesh silica gel and mobile phase was ethyl acetate:n-hexane = 1:4, volumetric ratio) to obtain 8 g of the product N4,N4-bis(4-methoxyphenyl)-[1,1'-biphenyl]-4-amine in a yield of 86.9%. 1H NMR (CDCl3, 400 MHz): 3.77 (6H, s), 6.71 (4H, ddd, J = 8.7, 2, 7, 0.5 Hz), 6.91-7.15 (6H, 6.97 (ddd, J = 8.9, 1.5, 0.5 Hz) , 7, 09 (ddd, J = 8, 7, 1, 3, 0.5 Hz) ) , 7, 27-7, 43 (4H, 7, 33 (ddd, J = 8, 7, 1, 4, 0.5 Hz) , 7, 37 (ddd, J = 8, 9, 1, 5, 0.5 Hz) ), 7, 53 (2H, ddd, J = 8, 7, 1, 7, 0, 5 Hz) . Step S5: Synthesis of N4,N4,N4'-tris(4-methoxyphenyl)-[1,1'-biphenyl]-4,4'-diamine. The N4,N4-bis(4-methoxyphenyl)-[1,1'-biphenyl]-4-amine (20 mmol) prepared in step S4, p-methoxyaniline (24 mmol), Pd2(dba)3 (0.4 mmol), Cs2CO3 (40 mmol), tri-tert-butylphosphine (1.6 mmol), and 200 mL of toluene were sequentially added to a Schlenk tube. A vacuum was then applied to the Schlenk tube, and argon was introduced. This operation was repeated three times to maintain the Schlenk tube filled with argon. The reaction mixture was then reacted in argon for 24 h at 110 °C. After the reaction was complete, the mixture was extracted with saturated saline solution (50 mL each time, four times in total). The organic layer was dried with anhydrous MgSO4, filtered and evaporated to dryness under reduced pressure to obtain a crude product.The crude product was separated by column chromatography (stationary phase was 200-300 mesh silica gel and mobile phase was ethyl acetate:n-hexane = 1:2, volumetric ratio) to obtain 8.12 g of the product N4,N4,N4'-tris(4-methoxyphenyl)-[1,1'-biphenyl]-4,4'-diamine with a yield of 80.84%. 1H NMR (CDCl3, 400 MHz): 3.70-3.82 (9H, 3.75 (s), 3.77 (s)), 6.63-6.78 (6H, 6.69 (ddd, J = 8.7, 2.7, 0.5 Hz), 6.71 (ddd, J = 8, 7, 2, 7, 0.5 Hz) ) , 7, 01 (2H, ddd, J = 8, 7, 1, 3, 0.5 Hz) , 7, 14-7, 38 (6H, 7, 20 (ddd, J = 9, 0, 1, 8, 0.5 Hz) , 7, 31 (ddd, J = 9, 0, 1, 2, 0, 5 Hz), 7, 32 (ddd, J = 8, 8, 1, 8, 0, 6 Hz)), 7, 43-7, 66 (6H, 7, 49 (ddd, J = 8, 8, 1, 6, 0, 6 Hz)), 7, 60 (ddd, J = 8, 7, 1, 3, 0, 5 Hz) ) . Step S6: 5'-(4-(bis(4-ethylphenyl)amino)phenyl)-N4-(4'-(bis(4-methoxyphenyl)amino)-[1,1'-biphenyl]-4-yl)-N4,N4',N4'-tris(4-methoxyphenyl)-[1,1':3',1'-triphenyl]-4,4'-diamina (formula (I-1)) The N4,N4,N4'-tris(4-methoxyphenyl)-[1,1'-biphenyl]-4,4'-diamine prepared in step S5, the 5'-(4-bromophenyl)-N4,N4,N4',N4'-tetrakis(4-methoxyphenyl)-[1,1':3',1'-triphenyl]-4,4'-diamine (1 mmol) prepared in step S3, Pd2(dba)3 (0.2 mmol), Cs2CO3 (20 mmol), tri-tert-butylphosphine (0.8 mmol), and 100 mL of toluene were sequentially added to a Schlenk tube. A vacuum was then applied to the Schlenk tube, and argon was introduced. This operation was repeated three times to maintain the Schlenk tube filled with argon. In argon, the reaction mixture was reacted for 24 h at 110 °C. After the reaction was complete, the mixture was extracted with saturated saline solution (50 ml each time, 4 times in total). The organic layer was dried with anhydrous MgSO4, filtered, and evaporated to dryness under reduced pressure to obtain a crude product.The crude product was separated by column chromatography (the stationary phase was 200-300 mesh silica gel and the mobile phase was dichloromethane:n-hexane = 1:2, volumetric ratio) to obtain 0.3 g of product of formula (I-1) with a yield of 23.81%.RMN de 1H (CDCl3, 400 MHz) : 3, 70-3, 80 (21H, 3, 75 (s) , 3, 75 (s) , 3, 75 (s) ) , 6, 65-6, 78 (12H, 6, 71 (ddd, J = 8, 7, 2, 7, 0, 5 Hz) , 6, 71 (ddd, J = 8, 7, 2, 7, 0, 5 Hz) ) , 6, 87 (2H, ddd, J = 8, 7, 2, 7, 0, 5 Hz) , 7, 02-7, 41 (24H, 7, 08 (ddd, J = 8, 7, 1, 3, 0, 5 Hz) , 7, 21 (ddd, J = 8, 9, 1, 5, 0, 5 Hz) , 7, 29 (ddd, J = 8, 8, 1, 7, 0, 5 Hz) , 7, 31 (ddd, J = 8, 9, 1, 7, 0, 5 Hz) , 7, 34 (ddd, J = 8, 9, 1, 6, 0, 5 Hz) , 7, 34 (ddd, J = 8, 9, 1, 6, 0, 5 Hz) , 7, 35 (ddd, J = 8, 9, 1, 6, 0, 5 Hz) ) , 7, 44-7, 71 (10H, 7, 50 (ddd, J = 8, 9, 1, 5, 0, 5 Hz) , 7, 53 (ddd, J = 8, 8, 1, 6, 0, 5 Hz) , 7, 60 (ddd, J = 8, 7, 1, 5, 0, 5 Hz) , 7, 64 (ddd, J = 8, 7, 1, 5, 0, 5 Hz) ) , 7, 93-8, 04 (3H, 7, 99 (t, J = 1, 9 Hz) , 7, 99 (t, J = 1, 9 Hz) ) . Example 2: Synthesis of (E) -5'- (4- (bis (4-metoxifenil) amino) fenil) -N4- (4- (4-bis (4-metoxifenil) amino) estiril) fenil) -N4, N4''N4''-tris (4-metoxifenil) -[1, 1:3', 1'-trifenil]-4, 4'-diamine (compuesto de fórmula (I-2) ) . Step S4-2: Synthesis of (E) -4- (4-bromoestyryl) -N, N-bis (4-methoxiphenyl) aniline Stage a): Synthesis of 1, 2-bis (4-bromophenyl) ethylene (4-Bromobenzyl) diethyl phosphonate (2.71 g, 11.0 mmol, purchased from Bide Pharmatech, CAS: 38186-51-5), potassium tert-butoxide (3.37 g, 30.0 mmol), and 20 mL of tetrahydrofuran were successively added to a round-bottom flask. In an ice-water bath, the reaction mixture was stirred for 5 min, and then 4-bromobenzaldehyde (1.85 g, 10.0 mmol) was added. The solution was maintained at 0 °C and stirred continuously for 5 h, and 10 mL of ice-water were added to stop the reaction. The solution was then extracted (50 mL each time, 3 times in total). The organic layer was dried with anhydrous MgSO4, filtered and concentrated under reduced pressure to obtain a crude product.The crude product was separated by column chromatography (the stationary phase was 200-300 mesh silica gel and the mobile phase was ethyl acetate:petroleum ether = 1:8, volumetric ratio) to obtain 3.12 g of the product 1,2-bis(4-bromophenyl)ethylene with a yield of 84.44%. Step b): Synthesis of (E)-4-(4-bromostyryl)-N,N-bis(4-methoxyphenyl)aniline The 1,2-bis(4-bromophenyl)ethylene (10 mmol) synthesized in step a), 4,4-dimethoxydiphenylamine (12 mmol), Pd2(dba)3 (0.2 mmol), Cs2CO3 (20 mmol), tri-tert-butylphosphine (0.8 mmol), and 100 mL of toluene were sequentially added to a Schlenk tube. A vacuum was then applied to the Schlenk tube, and argon was introduced. This operation was repeated three times to maintain the Schlenk tube filled with argon. In argon, the reaction mixture was stirred for 24 h at 110 °C. After the reaction was complete, the mixture was extracted with saturated saline solution (50 mL each time, four times in total). The organic layer was dried with anhydrous MgSO4, filtered and evaporated to dryness under reduced pressure to obtain a crude product.The crude product was separated by column chromatography (the stationary phase was 200-300 mesh silica gel and the mobile phase was ethyl acetate:n-hexane = 1:4, volumetric ratio) to obtain 5.12 g of (E)-4-(4-bromostyryl)-N,N-bis(4-methoxyphenyl)aniline with a yield of 52.78%. 1H NMR (CDCl3, 400 MHz): 3.75 (6H, s), 6.58 (2H, ddd, J = 8.2, 2, 3, 0.5 Hz), 6.72 (4H, ddd, J = 8.7, 2.7, 0.5 Hz), 6.97-7, 27 (10H, 7, 03 (d, J = 13, 9 Hz), 7, 09 (ddd, J = 8, 4, 1, 9, 0, 5 Hz), 7, 09 (ddd, J = 8, 7, 1, 5, 0, 5 Hz), 7, 12 (d, J = 13, 9 Hz), 7, 21 (ddd, J = 8, 2, 1, 9, 0.5 Hz), 7, 37 (2H, ddd, J = 8, 4, 1, 5, 0.5 Hz). Step S5-2: Synthesis of (E)-4-methoxy-N-(4-methoxyphenyl)-N-(4-(4-(4-methoxyphenyl)amino)styryl)phenyl)aniline The (E)-4-(4-bromostyryl)-N,N-bis(4-methoxyphenyl)aniline (10 mmol) prepared in step S4-2, p-methoxyaniline (12 mmol), Pd2(dba)3 (0.2 mmol), Cs2CO3 (20 mmol), tri-tert-butylphosphine (0.8 mmol), and 100 mL of toluene were sequentially added to a Schlenk tube. A vacuum was then applied to the Schlenk tube, and argon was introduced. This operation was repeated three times to maintain the Schlenk tube filled with argon. The reaction mixture was then reacted in argon for 24 h at 110 °C. After the reaction was complete, the mixture was extracted with saturated saline solution (50 mL each time, four times in total). The organic layer was dried with anhydrous MgSO4, filtered and evaporated to dryness under reduced pressure to obtain a crude product.The crude product was separated by column chromatography (the stationary phase was 200-300 mesh silica gel and the mobile phase was ethyl acetate:n-hexane = 1:4, volumetric ratio) to obtain 3.56 g of product (E) -4-methoxy-N- (4-methoxyphenyl) -N- (4- (4- (4- (4-methoxyphenyl) amino) styryl) phenyl) aniline with a yield of 67.4%. 1H NMR (CDCl3, 400 MHz): 3.70-3.81 (9H, 3.75 (s), 3.76 (s)), 6.56-6.90 (8H, 6.62 (ddd, J = 8.8, 2.7, 0.5 Hz), 6.72 (ddd, J = 8, 7, 2, 7, 0, 5 Hz), 6, 84 (ddd, J = 8, 3, 1, 4, 0, 5 Hz)), 6, 90-7, 30 (14H, 6, 97 (d, J = 14, 1 Hz)), 7, 00 (d, J = 14, 1 Hz), 7, 02 (ddd, J = 8, 8, 1, 4, 0.5 Hz), 7, 09 (ddd, J = 8, 7, 1, 5, 0, 5 Hz), 7, 20 (ddd, J = 8, 3, 2, 1, 0, 5 Hz), 7, 22 (ddd, J = 8, 3, 1, 9, 0, 5 Hz), 7, 24 (ddd, J = 8, 3, 2, 0, 0, 5 Hz) ) . Step S6-2: Synthesis of (E)-5'- (4- (bis (4-methoxyphenyl) amino) phenyl) -N4- (4- (4- (4-methoxyphenyl) amino) styryl) phenyl) -N4, N4''N4''-tris (4-methoxyphenyl) -[1, 1:3', 1'-triphenyl]-4, 4'-diamina (formula (I-2) ) (E) -4-methoxy-N- (4-methoxyphenyl) -N- (4- (4- (4-methoxyphenyl) amino) styryl) phenyl) aniline (1 mmol) prepared in step S5-2, 5'- (4-bromophenyl) -N4, N4, N4', N4'-tetrakis (4-methoxyphenyl) -[1, 1':3', 1'-triphenyl]-4,4'-diamine (1 mmol) prepared in step S3 of example 1, Pd2(dba)3 (0.2 mmol), Cs2CO3 (20 mmol), tri-tert-butylphosphine (0.8 mmol) and 100 ml of toluene were added to a Schlenk tube. Next, a vacuum was applied to the Schlenk tube and argon was introduced. This process was repeated three times to maintain the Schlenk tube filled with argon. The reaction mixture was then reacted in argon for 24 h at 110 °C. After the reaction was complete, the mixture was extracted with saturated saline solution (50 mL each time, four times in total). The organic layer was dried with anhydrous MgSO₄, filtered, and steamed to dryness under reduced pressure to obtain a crude product.The crude product was separated by column chromatography (stationary phase was 200-300 mesh silica gel and mobile phase was dichloromethane:petroleum ether = 1:2, volumetric ratio) to obtain 0.5 g of product of formula (I-2) with a yield of 38.9%. RMN de 1H (CDCl3, 400 MHz) : 3, 70-3, 80 (21H, 3, 75 (s) , 3, 75 (s) , 3, 75 (s) ) , 6, 65-6, 78 (12H, 6, 71 (ddd, J = 8, 7, 2, 7, 0, 5 Hz) , 6, 72 (ddd, J = 8, 7, 2, 7, 0, 5 Hz) ) , 6, 81-7, 16 (20H, 6, 87 (ddd, J = 8, 7, 2, 6, 0, 5 Hz) , 6, 87 (ddd, J = 8, 3, 1, 6, 0, 5 Hz) , 6, 94 (ddd, J = 8, 7, 1, 5, 0, 5 Hz) , 7, 03 (d, J = 13, 9 Hz) , 7, 04 (d, J = 13, 9 Hz) , 7, 08 (ddd, J = 8, 7, 1, 3, 0, 5 Hz) , 7, 09 (ddd, J = 8, 7, 1, 5, 0, 5 Hz) ) , 7, 17-7, 41 (18H, 7, 23 (ddd, J = 8, 3, 1, 9, 0, 5 Hz) , 7, 24 (ddd, J = 8, 3, 2, 1, 0, 5 Hz) , 7, 24 (ddd, J = 8, 3, 1, 9, 0, 5 Hz) , 7, 28 (ddd, J = 8, 9, 1, 5, 0, 5 Hz) , 7, 34 (ddd, J = 8, 9, 1, 6, 0, 5 Hz) , 7, 34 (ddd, J = 8, 9, 1, 6, 0, 5 Hz) , 7, 35 (ddd, J = 8, 9, 1, 6, 0, 5 Hz) ) , 7, 94-8, 04 (3H, 7, 99 (t, J = 1, 9 Hz) , 7, 99 (t, J = 1, 9 Hz) ) . Example 3: Synthesis of 5'- (4- (bis (4-methoxyphenyl) amino) phenyl) -N4- (4- (5- (4- (bis (4-methoxyphenyl) amino) phenyl) tiofen-2-yl) phenyl) -N4, N4'', N4'-tris (4-methoxyphenyl) - (1, 1:3', 1'-triphenyl]-4, 4'-diamine (un compuesto de fórmula (I-3) ) Stage S4-3: Synthesis of 4- (5- (4-bromophenyl) tiofen-2-yl) -N, N-bis (4-methoxyphenyl) aniline Step a) : Synthesis of 2, 5-bis (4-bromophenyl) thiophene 1,4-bis(4-bromophenyl)butane-1,4-dione (4.023 g, 10 mmol, purchased from Bide Pharmatech, CAS: 2461-83-8) and Lawesson's reagent (6.362 g, 15 mmol, purchased from Bide Pharmatech, CAS: 19172-47-5) were added to a round-bottom flask. A vacuum was then applied to the Schlenk tube, and argon was introduced. This operation was repeated three times to maintain the Schlenk tube filled with argon. Sixty milliliters of hexafluoroisopropanol (purchased from Bide Pharmatech, CAS: 920-66-1) were added to the argon. The reaction mixture was then refluxed in argon for 18 h. After the reaction was completed, it was evaporated to dryness to obtain a crude product. The crude product was separated by column chromatography (the stationary phase was 200-300 mesh silica gel and the mobile phase was ethyl acetate:n-hexane = 1:8, volumetric ratio) to obtain 3.85 g of the product 2,5-bis(4-bromophenyl)thiophene with a yield of 98.21%. NMR of 1H (CDCl3, 400 MHz): 7, 26-7, 42 (6H, 7, 33 (ddd, J = 8, 7, 1, 5, 0, 5 Hz) , 7, 36 (d, J = 8, 8 Hz) ) , 7, 5, 3, J = 8, 8 Hz 1, 5, 0, 5 Hz) . Step b) : Synthesis of 4-(5-(4-bromophenyl)thiophen-2-yl)-N,N-bis(4-methoxyphenyl)aniline The 2,5-bis(4-bromophenyl)thiophene (10 mmol) prepared in step a), 4,4-dimethoxydiphenylamine (12 mmol), Pd2(dba)3 (0.2 mmol), Cs2CO3 (20 mmol), tri-tert-butylphosphine (0.8 mmol), and 100 mL of toluene were sequentially added to a Schlenk tube. A vacuum was then applied to the Schlenk tube, and argon was introduced. This operation was repeated three times to maintain the Schlenk tube filled with argon. The reaction mixture was stirred in argon for 24 h at 110 °C. After the reaction was complete, the mixture was extracted with saturated saline solution (50 mL each time, four times in total). The organic layer was dried with anhydrous MgSO4, filtered and evaporated to dryness under reduced pressure to obtain a crude product.The crude product was separated by column chromatography (the stationary phase was 200–300 mesh silica gel and the mobile phase was ethyl acetate:n-hexane = 1:4, in volume ratio) to afford 3.89 g of 4- (5- (4-)thiophenol-2-bromo-Nyl (4-methoxyphenyl) aniline with a yield of a 71. 77 %. NMR of 1H (CDCl3, 400 MHz): 3, 75 (6H, s), 6, 71 (4H, ddd, J = 8, 7, 2, 7, 0, 5 Hz), 7, 09 (4H, ddd, J = 8, 7, 7, Hz) 0, 1, 17–7, 56 (10H, 7, 23 (d, J = 8, 5 Hz) , 7, 30 (d, J = 8, 5 Hz), 7, 38 (ddd, J = 8, 7, 1, 5, 0, 5 Hz) , 1, 8, 7, J = 0 5 Hz), 7, 45 (ddd, J = 8.9, 1, 6, 0.5 Hz) , 7, 50 (ddd, J = 8, 7, 1, 6, 0, 5 Hz) ). Stage S5-3: Synthesis of 4-methoxy-N- (4-methoxyphenyl) -N- (4- (5- (4- (4-(4-methoxyphenyl) amino) phenyl) thiophen-2-yl) phenyl) aniline The 4-(5-(4-bromophenyl)thiophen-2-yl)-N,N-bis(4-methoxyphenyl)aniline (10 mmol) prepared in step S4-3, p-methoxyaniline (12 mmol), Pd2(dba)3 (0.2 mmol), Cs2CO3 (20 mmol), tri-tert-butylphosphine (0.8 mmol), and 100 mL of toluene were sequentially added to a Schlenk tube. A vacuum was then applied to the Schlenk tube, and argon was introduced. This operation was repeated three times to maintain the Schlenk tube filled with argon. The reaction mixture was then reacted in argon for 24 h at 110 °C. After the reaction was complete, the mixture was extracted with saturated saline solution (50 mL each time, four times in total). The organic layer was dried with anhydrous MgSO4, filtered and evaporated to dryness under reduced pressure to obtain a crude product.The crude product was separated by column chromatography (the stationary phase was 200–300 mesh silica gel and the mobile phase was ethyl acetate:n-hexane = 1:4) to obtain 4.12 g of the product 4-methoxy-N- (4-methoxy-phenyl (4-methoxy4-(4)-Nmethoxyphenyl (4-5-N-phenyl) (4-methoxyphenyl) (4-methoxyphenyl) ( amino) phenyl) thiophene-2-yl) phenyl) aniline in a yield of about 70. 46 %. NMR of 1H (CDCl3, 400 MHz): 3, 69-3, 80 (9H, 3, 74 (s) , 3, 75 (s) ) , 6, 56-6, 78 ( 6H, 6, 63 (ddd, J = 8, 7, 8, 2 (ddd, J = 8, 7, 2, 7, 0, 5 Hz) ) , 6, 99 (2H, ddd, J = 8, 8, 1, 6, 0, 5 Hz) , 7, 22-7, 40 (6H, 7, 29 (ddd, 5, 0, J = 9) 7, 30 (ddd, J = 8, 9, 1, 5, 0, 5 Hz) , 7, 31 (d, J = 8, 5 Hz) , 7, 34 (d, J = 8, 5 Hz) , 7, 43-7, 0, 66 (8H = 1, 9 ( dd 7, 7, 0, 66 0.5 Hz), 7.53 (ddd, J = 8.9, 1, 7, 0.5 Hz) , 7.60 (ddd, J = 8.7, 1, 3, 0.5 Hz) Step S6-3: Synthesis of 5'-(4-(bis(4-methoxyphenyl)amino)phenyl)-N4-(4-(5-(4-bis(methoxyphenyl)amino)phenyl)thiophen-2-yl)phenyl)-N4, N4'', N4'-tris(4-methoxyphenyl)-(1, 1:3', 1'-triphenyl]-4, 4'-diamina (formula (I-3) ) 4-Methoxy-N-(4-methoxyphenyl)-N-(4-(5-(4-(4-methoxyphenyl)amino)phenyl)thiophen-2-yl)phenyl)aniline (1 mmol) prepared in step S5-3, 5'-(4-bromophenyl)-N4, N4, N4', N4'-tetrakis(4-methoxyphenyl)-[1, 1':3', 1'-triphenyl]-4, 4'-diamine (1 mmol) prepared in step S3 of example 1, Pd2 (dba) 3 (0.2 mmol), Cs2CO3 (20 mmol), tri-tert-butylphosphine (0.8 mmol) and 100 ml of toluene were sequentially added to a Schlenk tube. Next, a vacuum was applied to the Schlenk tube and argon was introduced. This process was repeated three times to maintain the Schlenk tube filled with argon. The reaction mixture was stirred in argon for 24 h at 110 °C. After the reaction was complete, the mixture was extracted with saturated saline solution (50 mL each time, four times in total). The organic layer was dried with anhydrous MgSO₄, filtered, and evaporated to dryness under reduced pressure to obtain a crude product.The crude product was separated by column chromatography (the stationary phase was 200-300 mesh silica gel and the mobile phase was dichloromethane:petroleum ether = 1:2, volumetric ratio) to obtain 0.52 g of product of formula (I-3) with a yield of 38.74%. RMN de 1H (CDCl3, 400 MHz) : 3, 70-3, 80 (21H, 3, 75 (s) , 3, 75 (s) , 3, 75 (s) ) , 6, 65-6, 79 (12H, 6, 71 (ddd, J = 8, 7, 2, 7, 0, 5 Hz) , 6, 72 (ddd, J = 8, 7, 2, 7, 0, 5 Hz) ) , 6, 87 (2H, ddd, J = 8, 7, 2, 7, 0, 5 Hz) , 7, 02-7, 43 (28H, 7, 08 (ddd, J = 8, 7, 1, 3, 0, 5 Hz) , 7, 11 (ddd, J = 8, 7, 1, 5, 0, 5 Hz) , 7, 22 (ddd, J = 8, 9, 1, 5, 0, 5 Hz) , 7, 34 (ddd, J = 8, 9, 1, 6, 0, 5 Hz) , 7, 34 (ddd, J = 8, 9, 1, 6, 0, 5 Hz) , 7, 35 (ddd, J = 8, 9, 1, 6, 0, 5 Hz) , 7, 36 (ddd, J = 8, 9, 1, 5, 0, 5 Hz) , 7, 36 (ddd, J = 9, 0, 1, 5, 0, 5 Hz) , 7, 36 (d, J = 8, 6 Hz) , 7, 37 (d, J = 8, 6 Hz) ) , 7, 45-7, 66 (8H, 7, 51 (ddd, J = 9, 0, 1, 9, 0, 5 Hz) , 7, 52 (ddd, J = 8, 9, 1, 6, 0, 5 Hz) , 7, 60 (ddd, J = 8, 7, 1, 5, 0, 5 Hz) ) , 7, 94-8, 04 (3H, 7, 99 (t, J = 1, 9 Hz) , 7, 99 (t, J = 1, 9 Hz) ) . III. Preparación de célula de perovskita Ejemplo de dispositivo 1 1) A 2.0 cm × 2.0 cm FTO conductive glass was taken and 0.35 cm of FTO was removed from each of the two ends by laser etching to expose the glass substrate. 2) The etched FTO conductive glass was ultrasonically cleaned several times sequentially with water, acetone, and isopropanol. 3) The FTO conductive glass was blow-dried with a nitrogen gun to remove the solvent and placed in an ozone and UV machine for further cleaning. 4) The same volume of water was mixed with an aqueous solution of SnO2 (acquired from Sigma) to obtain an SnO2 diluent; 70 µl of SnO2 solution were taken, centrifugally coated onto an FTO layer at 3000 rpm / s, annealed at 100 °C for 30 min after centrifugal coating and cooled to room temperature, to form an electron transport layer with a thickness of 20 nm. 5) 0.5531 g of lead iodide, 0.1842 g of formamidine iodide, 0.0156 g of cesium iodide, 0.1255 g of methylammonium bromide, 0.1213 g of lead bromide were weighed and dissolved in a mixed solution (1 ml) of DMF and DMSO in a volumetric ratio of 1:4, stirred for 3 h and filtered with a 0.22 µm organic filter membrane to obtain a perovskite precursor solution; 0.1 ml of perovskite precursor solution was centrifuged onto a layer of SnO2 at 3000 rpm / s, annealed at 100 °C for 30 min and cooled to room temperature, thus forming a perovskite layer 500 nm thick; and the chemical formula of the perovskite was (Cs0.05FA0.93MA0.02)Pb(I0.98Br0.02)3, where Lead iodide, formamidine iodide, cesium iodide, methyl ammonium bromide, and lead bromide were acquired from Xi'an p-OLED Optoelectronic Materials Co., Ltd., and DMF and DMSO were acquired from Sigma. 6) 0.1 g of void transport layer material of formula (I-1) was weighed and dissolved in 2 ml of chlorobenzene to obtain a void transport layer solution, and the void transport layer solution (60 µl) was coated by centrifugation onto a perovskite absorption layer at 3000 rpm / s; and, consequently, a void transport layer with a thickness of 60 nm was formed. 7) The preparation pieces obtained previously by steps 1)-6) which include the FTO conductive glass, electron transport layer, perovskite layer and hole transport layer, were scraped with a blade according to a mask pattern to remove a portion of the functional layers (including the electron transport layer, perovskite layer and hole transport layer) to expose the conductive glass layer; the remaining functional layers were then cleaned with a washing solution; this object was then placed on an evaporation mask plate and 80 nm of silver was evaporated onto the exposed conductive glass in a vacuum evaporation apparatus with an evaporation rate of 0.1 A / s; and after evaporation, a complete perovskite solar cell was obtained. Example device 2 The process for preparing a perovskite solar cell as a whole refers to Device Example 1, with the difference that, in preparing the void transport layer in step 6) of this example, the compound (0.1 g) of formula (I-2) of this disclosure was used instead of the compound of formula (I-1). Therefore, a perovskite solar cell of Device Example 2 was prepared. Example of device 3 The process for preparing a perovskite solar cell as a whole refers to Device Example 1, with the difference that, in preparing the void transport layer in step 6) of this example, the compound (0.1 g) of formula (I-3) of this disclosure was used instead of the compound of formula (I-1). Therefore, a perovskite solar cell of Device Example 2 was prepared. Comparative example of device 1 The process for preparing a perovskite solar cell as a whole refers to Device Example 1, with the difference that, in preparing the hole transport layer of step 6) of the comparative example, the Spiro-OMeTAD compound of formula (A) (0.1 g, acquired from Xi'an p-OLED Optoelectronic Materials Co., Ltd.) was used instead of the compound (I-1) (0.1 g) of the present disclosure. Therefore, a perovskite cell of Comparative Device Example 1 was prepared. Comparative example of device 2 The process of preparing a perovskite solar cell as a whole refers to example device 1, with the difference that the preparation of the void transport layer of step 6) in this comparative example was as follows: A 4-tert-butylpyridine (TBP) additive (30 µg), an acetonitrile solution (18 µl) of bis(trifluoromethanesulfonyl)lithium (Li-TFSI) having a concentration of 520 mg / ml and an acetonitrile solution (29 µl) of FK209 having a concentration of 300 mg / ml were added to 1 ml of chlorobenzene solution of the compound Spiro-OMeTAD of formula (A) (73 mg, procured from Xi'an p-OLED Optoelectronic Materials Co., Ltd.) to obtain a gap transport layer solution; the gap transport layer solution (60 µl) was then centrifugally coated onto the perovskite absorbent layer at 3000 rpm / s; and therefore a perovskite cell was prepared from comparative device example 2. Test method 1. Method for determining the HOMO energy level The sample preparation method includes: taking a cleaned glass plate, centrifugally coating a test material onto the glass plate (instead of a perovskite absorption layer) according to Examples 1-3 and Comparative Examples 1-2, and annealing it to obtain a thin film of the test material. The previously prepared sample was determined by UPS ultraviolet photoelectron spectroscopy (AXIS ULTRADLD of Kratos Company) to obtain a HOMO energy level of the material to be tested, which was the HOMO energy level of the hole transport layer. The compound of formula (I-1) in this disclosure has a HOMO energy level of -5.2 eV, the compound of formula (I-2) has a HOMO energy level of -5.1 eV, and the compound of formula (I-3) has a HOMO energy level of -5.2 eV. The commonly used void carrier material Spiro-OMeTAD has a HOMO energy level of -5.0 eV. The commonly used composition material containing Spiro-OMeTAD and the additives TBP, Li-TFSI, and FK209 has a HOMO energy level of -5.1 eV. 2. Method for determining the mobility of the voids The void mobility of the void transport layer material was determined using a space charge limiting current (SCLC) method, according to a method described in the literature (Synthesis and Device Characterization of A High-mobility Material for Polymer Solar Cells [J]. Yang Dalei, et al.; Applied Chemistry, 33(12): 1375-1382), and the thickness of the void transport layer was 60 nm. The void mobility of the material under test, i.e., the void mobility of the void transport layer, was thus obtained. The structure of the test device was ITO / poly(3,4-ethylenedioxythiophenesulfonate polystyrene) (PEDOT:PSS) / void transport layer / Au. The process of preparing the test device was as follows: The ITO glass was cleaned sequentially using ultrasonics in an aqueous solution of detergent, secondary water, isopropanol, and acetone for 20 min. The cleaned ITO glass was then dried with high-purity N2 gas, placed in an ozone and UV cleaning machine, and processed for 30 min. A 30 nm thick PEDOT:PSS interface layer was then spin-coated onto the cleaned ITO glass using a spin-coating machine. The spin-coated ITO glass was then baked on a hot plate at 150 °C under atmospheric conditions for 15 min to ensure no residual moisture remained in the film, resulting in preparation pieces with the PEDOT:PSS interface and the ITO glass layered sequentially.Next, the prepared parts with the PEDOT:PSS interface and the ITO glass were sequentially transferred to a glove box, and a void transport layer was prepared on the PEDOT:PSS interface according to the method in step 6 of Examples 1-3 and Comparative Examples 1-2, to obtain the prepared parts with the void transport layer, the PEDOT:PSS interface, and the ITO glass in sequence. Finally, the prepared parts with the void transport layer, the PEDOT:PSS interface, and the ITO glass in sequence were placed in a vacuum coating machine, and a 30 nm thick Au metal electrode was deposited in a high vacuum environment of less than 5 × 10⁻⁴ Pa. After annealing, the test device was obtained. The compound of formula (I-1) in this disclosure has a hole mobility of 3.5 × 10⁻⁴ cm²V⁻¹s⁻¹, the compound of formula (I-2) has a HOMO energy level of 5.0 × 10⁻⁴ cm²V⁻¹s⁻¹, and the compound of formula (I-3) has a HOMO energy level of 2.0 × 10⁻⁴ cm²V⁻¹s⁻¹. The commonly used hole transport material Spiro-OMeTAD has a hole mobility of 2.4 × 10⁻⁵ cm²V⁻¹s⁻¹. The commonly used composition material containing Spiro-OMeTAD and the additives TBP, Li-TFSI, and FK209 has a hole mobility of 3.0 × 10⁻⁴ cm²V⁻¹s⁻¹. 3. Method for Determining the Upper Energy Level of the Valence Band of the Perovskite Layer. The method for preparing a perovskite sample comprises: taking a cleaned glass foil; and preparing it according to step 5 of Example 1 as described above, with the difference that a glass foil was used instead of the SnO2 layer; and a perovskite film was obtained after annealing. Ultraviolet photoelectron spectroscopy (UPS) (AXIS ULTRADLD from Kratos Company) was used to determine the upper energy level of the valence band of the perovskite prepared sample, which was the upper energy level of the valence band of the perovskite layer. 4. Method for determining the photoelectric conversion rate (IV) of the device Perovskite solar cell test (test IV): A Guangyan solar simulator was used to perform the test in accordance with the national standard IEC61215; a crystalline silicon solar cell was used to correct the light intensity to achieve a solar intensity of AM 1.5; and the cell was connected to a digital source table, and its photoelectric conversion efficiency was measured under light. In Table 1, the upper energy level of the valence band of the perovskite layer was expressed as E1; the HOMO energy level of the hole transport layer was expressed as E2; and the difference between the upper energy level of the valence band of the perovskite layer and the HOMO energy level of the hole transport layer was expressed as E = E2 - E1. Table 1 Compared to comparative examples 1 and 2, examples 1 to 3 of this disclosure have achieved higher photoelectric conversion efficiency and better stability. Compared to the commonly used gap transport material Spiro-OMeTAD, the compound of formula (I) in this disclosure has a deeper HOMO energy level and greater gap mobility, achieved by changing the arrangement of the four triphenylamine groups in the molecule. Consequently, the same is true for the gap transport layer. The gap transport layer formed from the compound of formula (I) also has a deeper HOMO energy level and greater gap mobility, as shown in Table 1. It can be observed that the difference (absolute value) between the HOMO energy level of the compound in this disclosure and the HOMO energy level of the perovskite layer is smaller, making it more suitable for matching with the perovskite layer formed from lead iodide, formamidine iodide, cesium iodide, methylammonium bromide, and lead bromide. Compared to commonly used composite materials, including Spiro-OMeTAD and the additives TBP, Li-TFSI, and FK209, the compound of formula (I) described herein has comparable or improved HOMO energy levels and hole mobility. The same is true for the hole transport layer, as shown in Table 1. Furthermore, the perovskite solar cell made from the compound of formula (I) described herein has significantly improved photoelectric conversion efficiency and long-term stability.

Claims

1. A compound having a structure of formula (I), wherein R1 is trivalent phenyl; R2 is a single bond, a C2-C6 conjugated alkylene, or a 5- or 6-membered unsaturated ring group containing heteroatoms selected from O, S, or Se.

2. A compound according to claim 1, wherein R2 is a single bond, vinylidene, furylidene, thiophenylene, or selenophenylene.

3. A compound according to claim 1 or 2, wherein R1 is 1,3,5-benzenetriyl.

4. A compound according to claim 1 or 2, wherein R1 is 1,2,4-benzenetriyl.

5. A compound according to claim 1 or 2, wherein R1 is 1,2,3-benzenetriyl.

6. The compound according to claim 1, wherein the compound of formula (I) is a compound of formula (I-1), formula (I-2) or formula (I-3), 7. The compound according to any preceding claim, wherein the compound has a HOMO energy level ranging from -5.05 eV to -5.30 eV,optionally ranging from -5.1 eV to -5.2 eV, and a charge mobility ranging from 1.0 × 10⁻⁴ cm²V⁻¹s⁻¹ to 8.0 × 10⁻⁴ cm²V⁻¹s⁻¹, optionally ranging from 2.0 × 10⁻⁴ cm²V⁻¹s⁻¹ to 6.0 × 10⁻⁴ cm²V⁻¹s⁻¹.

8. A method of preparing the compounds according to any one of claims 1 to 7, comprising the following steps: step 1 of preparing a compound of formula (II): 4,4'-dimethoxydiphenylamine and an iodobenzene dibromide of formula (1) undergo a coupling reaction to form an intermediate (2); intermediate (2) and 4-borate-4',4'-dimethoxytriphenylamine of formula (3) undergo a coupling reaction to generate an intermediate (4); and intermediate (4) and 2-(4-bromophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane of formula (5) undergo a coupling reaction to obtain the compound of formula (II); step 2 of preparation of a compound of formula (III): 4,4'-Dimethoxydiphenylamine and a compound of formula (6) undergo a coupling reaction to form an intermediate (7), and the intermediate (7) and p-methoxyaniline of formula (8) undergo a coupling reaction to generate the compound of formula (III); and step 3 of preparing a compound of formula (I): the compound of formula (II) and the compound of formula (III) undergo a coupling reaction in the presence of a palladium catalyst and an alkali to obtain the compound of formula (I).

9. Use of the compound according to any one of claims 1 to 7 or of the compound obtained according to the preparation method according to claim 8 as a void carrier material in a light-emitting device, wherein the light-emitting device comprises an organic electroluminescent device and a perovskite solar cell.

10. A perovskite solar cell, comprising conductive glass (1),an electron transport layer (2), a perovskite layer (3), a hole transport layer (4), and a metallic electrode (5), wherein the hole transport layer (4) comprises the compound according to any one of claims 1 to 7 or the compound obtained according to the preparation method according to claim 8.

11. The perovskite solar cell according to claim 10, wherein the hole transport layer (4) does not contain additives selected from lithium salts, cobalt salts, or cosolvents, including one or more of lithium salt of bis(trifluoromethane)sulfonimide, cobalt(III) salt of bis-trifluoromethanesulfonimide, and 4-tert-butylpyridine.

12. The perovskite solar cell according to claim 10 or 11, wherein the hole transport layer (4) has a HOMO energy level ranging from -5.05 eV to -5.30 eV, optionally ranging from -5.10 eV to -5.20 eV; and the perovskite layer (3) has an upper valence band energy level ranging from -5.30 eV to -5.60 eV, optionally ranging from -5.30 eV to -5.50 eV.

13. The perovskite solar cell according to any one of claims 10 to 12, wherein the HOMO energy level of the hole transport layer (4) is greater than the upper valence band energy level of the perovskite layer (3), with an energy level difference ranging from 0.35 eV to 0.05 eV, optionally ranging from 0.3 eV to 0.2 eV.

14. The perovskite solar cell according to any one of claims 10 to 13, wherein the void transport layer (4) has a thickness ranging from 5 nm to 100 nm, optionally ranging from 30 nm to 80 nm.

15. A method for preparing the perovskite solar cell according to any one of claims 10 to 14.comprising steps for preparing a void transport layer: dissolving the compound according to any one of claims 1 to 7 or the compound obtained according to the preparation method according to claim 8 in an organic solvent to prepare a void transport material solution; and coating the void transport material solution onto the surface of the perovskite layer and removing the solvent to obtain the void transport layer, wherein, when the perovskite solar cell is a forward-facing perovskite solar cell, the concentration of the compound in the void transport material solution ranges from 20 mg / ml to 100 mg / ml; when the perovskite solar cell is an inverted perovskite solar cell, the concentration of the compound in the void transport material solution ranges from 1 mg / ml to 50 mg / ml; and wherein the organic solvent is toluene, chlorobenzene, or dichloromethane.

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