Compound for hole transmission and photoelectric device

Abstract

The invention relates to a compound for transporting holes and a photoelectric device. The structural formula of the compound for transporting holes is shown in the specification, wherein R1-R6 are independently selected from one or a combination of more of hydrogen, alkyl, alkyl derivatives, sulfonic acid groups, alkoxy, aryl, aryl derivatives, carboxylic acid groups, phosphate groups, hydroxyl, sulfydryl, amino, amino derivatives, halogen groups and cyano groups. When the compound is used as a hole transport layer material, conjugation can be realized through a central structure, stable connection between a substrate and perovskite is realized through end diphosphoric acid, and a prepared photoelectric device is high in hole transport efficiency and high in thermal stability.

Description

Technical Field

[0001] This invention relates to a compound and optoelectronic device for transporting holes, belonging to the field of new materials. Background Technology

[0002] Since Japanese scientists first used organic-inorganic hybrid perovskite materials as the functional layer of solar cells in 2009, achieving an efficiency of 3.8%, perovskite solar cells have made rapid progress in the photovoltaic field, becoming one of the most representative photovoltaic technologies in recent years. In 2012, the emergence of all-solid-state structures replaced early liquid electrolytes, solving the stability problem of the cells to some extent; simultaneously, the introduction of chloride ions enabled the cell efficiency to exceed 10%, laying the foundation for the commercialization of perovskite solar cells. With the optimization of material composition and device structure, in 2015, the efficiency of perovskite solar cells successfully exceeded 20%, sparking wider attention from researchers. Currently, the efficiency of single-junction perovskite solar cells has reached over 27%. Meanwhile, due to the tunable bandgap of perovskite materials, the efficiency of perovskite-silicon tandem cells has reached over 34%, demonstrating the unique advantages of perovskite solar cells. However, the stability problem of perovskite solar cells remains a key factor restricting their practical application. The inherent environmental sensitivity of perovskite materials leads to numerous defects and non-radiative recombination centers at the device interface, severely impacting device performance and long-term stability. Optimizing the interface layer has become one of the effective strategies for improving the performance and stability of perovskite solar cell devices.

[0003] In recent years, self-assembled monolayers (SAMs) have attracted widespread research due to their advantages such as thinness, tunable energy levels, and good interfacial passivation capabilities. In 2013, PEDOT:PSS was introduced as a p-type layer into perovskite solar cell structures, proving the feasibility of the pin structure and laying the foundation for the subsequent introduction of SAMs. In 2018, phosphonic acid and carbazole-based SAMs replaced PEDOT:PSS and were directly used as hole transport layer materials, resulting in a significant improvement in device efficiency. By 2021, the combination of α-FAPbI3 perovskite and Me-4PACz successfully achieved a certified efficiency of over 25% for perovskite solar cell devices, demonstrating the great development potential of SAM-based perovskite solar cells. In 2022, SAMs overcame the bottleneck of large-area fabrication, achieving a thickness of 14.6 cm². 2 Achieving 21% efficiency on the module. Since 2024, more researchers have focused on the design of SAM molecules, improving energy level matching, enhancing hole extraction efficiency, and suppressing nonradiative recombination, which has greatly improved the applicability and functionality of SAM molecules.

[0004] However, despite the rapid development of SAM materials, the uniformity and density of the SAM layer distribution on the conductive substrate, as well as the stability of its anchoring with the perovskite film, remain to be solved. Summary of the Invention

[0005] To address the anchoring stability issue between existing SAM materials and the substrate and perovskite film, this invention provides a compound for hole transport. When used as a hole transport layer material, this compound achieves conjugation through its central structure and stable connection between the substrate and the perovskite through its terminal bisphosphonates. The resulting optoelectronic device exhibits high hole transport efficiency and strong thermal stability.

[0006] To achieve the above objectives, one technical solution adopted by the present invention is: a compound for transporting holes, with the following structural formula:

[0007] ;

[0008] In the formula: R1-R6 are each independently selected from one or more combinations of hydrogen, alkyl, alkyl derivatives, sulfonic acid group, alkoxy group, aromatic group, aromatic derivatives, carboxylic acid group, phosphate group, hydroxyl group, mercapto group, amino group, amino derivatives, halogen group, and cyano group.

[0009] As a preferred embodiment, the alkyl group is -C n H 2n+1 , 1≤n≤4.

[0010] As a preferred embodiment, R1 is selected from one or more combinations of alkyl, sulfonic acid, alkoxy, and aromatic groups; R2 is selected from one or more combinations of alkoxy, benzene ring, carboxylic acid, and alkyl groups; R3 is selected from one or more combinations of siloxane, alkyl, carboxylic acid, phosphoric acid, hydroxyl, mercapto, and halogen groups; R4 is selected from one or more combinations of carboxylic acid, alkyl, trifluoromethyl, hydroxyl, phosphoric acid, amino, and halogen groups; R5 is selected from one or more combinations of phosphoric acid, alkyl, and halogen groups; and R6 is selected from one or more combinations of alkoxy, cyano, and benzene ring groups.

[0011] As a preferred embodiment, R1 and R6 are the same; R2 and R5 are the same. R1 and R6 are both alkoxy groups; R2 and R5 are both hydroxy groups; R3 and R4 may be the same or different. If they are the same, they are selected from mercapto, carboxyl, amino, and hydroxyl groups. If they are different, R3 is mercapto and / or carboxylic acid; R4 is amino and / or hydroxyl.

[0012] The second technical solution adopted by the present invention is: to provide a device containing the compound of the first solution, which can be a photovoltaic device or a light-emitting device, wherein the compound plays the role of hole injection or transport.

[0013] Taking photovoltaic devices as an example, they are mainly used in perovskite solar cells. Perovskite solar cell devices include a conductive substrate, a hole transport layer, a perovskite film layer, an electron transport layer, and an electrode layer. The perovskite film layer generates free electrons and holes under laser light. Free electrons enter the electron transport layer, and holes enter the hole transport layer. The hole transport layer contains the compound in Scheme 1. It can contain only the compound in Scheme 1, or it can contain other materials in addition to the compound in Scheme 1, such as traditional hole transport layer materials, additives, passivators, etc.

[0014] The third technical solution adopted in this invention is as follows: A method for fabricating the device in the second solution is provided. Taking a perovskite solar cell as an example, the fabrication steps include: obtaining a substrate, fabricating a hole transport layer, fabricating a perovskite film layer, fabricating an electron transport layer, and fabricating an electrode layer. The hole transport layer is prepared by solution coating. Preferably, a modification layer is provided between the perovskite film layer and the electron transport layer. This modification layer is prepared by solution coating using EDAI2, and the concentration of the modification material solution is 0.5 mM to 0.5 M, preferably 0.1 M to 0.3 M.

[0015] The beneficial effects of this invention include:

[0016] In this invention, the lowest unoccupied molecular orbital (LOMO) of the compound molecule is close to the conduction band bottom of the conductive substrate material ITO / FTO, which reduces the charge injection barrier, helps to improve charge injection efficiency, and reduces energy loss.

[0017] In this invention, the highest occupied molecular orbital (HOMO) of the compound molecule is close to the valence band top of the perovskite material, which is beneficial for the efficient transport of photogenerated carriers between the perovskite film layer and the hole transport layer. This energy level arrangement facilitates the effective separation of photogenerated carriers.

[0018] The hole-transporting compound in this invention uses a thiophene ring and cyclopentane as its core and bisphosphonates as its terminal groups to provide a conjugated electronic structure and optimize electron injection efficiency. When used as a hole transport material, it can exhibit strong interactions with perovskite films and ITO / FTO substrates. The oxygen atom in its monophosphate group can coordinate with lead ions in the perovskite precursor solution, thereby regulating the nucleation rate and nucleation site of the perovskite, inducing uniform nucleation, suppressing defect formation, and improving battery performance. Its diphosphate group can act as a Lewis acid, coordinating with Lewis base sites such as oxygen vacancies or metal cations on the conductive substrate surface. The symmetrical structure of the two phosphate groups, both located at the ends, allows the molecules to be arranged vertically and uniformly.

[0019] In this invention, the compound achieves the following through the interaction of the main molecule and the R1-R6 site groups: (1) Improves the alcohol solubility of the molecule, facilitating solution processing of the molecule to obtain a uniform and dense molecular arrangement, which is beneficial for hole transport and improves device performance. (2) Enhances the anchoring effect of the molecule, forms a stable interface contact with the ITO substrate, reduces the interface resistance, improves the charge injection efficiency, and improves the battery performance. (3) Forms strong chemical bonds with halide ions in the perovskite solution, improves the crystal quality of the perovskite film, reduces the generation of defects, enhances the carrier mobility, and enhances the battery performance. (4) Adjusts the energy level of the main molecule structure, making the HOMO energy level of the molecule more matched with the valence band of the perovskite, promoting hole transport, reducing recombination loss, and improving device performance. (5) Forms a strong coordination bond with the surface of the conductive substrate, which can ensure that the molecule is stably anchored on the conductive substrate. (6) Forms hydrogen bonds with halide ions in the perovskite, which is beneficial for optimizing the crystallization kinetics of the perovskite and improving the crystal quality of the perovskite film. (7) It forms coordination bonds with metal ions on the ITO surface, creating a stable interfacial contact with the ITO substrate and reducing interfacial resistance. (8) It forms hydrogen bonds with cations in the perovskite, optimizing the perovskite crystallization process. (9) It forms strong coordination bonds with metal atoms on the conductive substrate, improving the stability of the molecule's anchorage on the conductive substrate. (10) It exhibits strong electronegativity, attracting the surrounding electron cloud, matching the highest occupied molecular orbital (HOMO) energy level of the molecule with the valence band of the perovskite, promoting hole transport, and improving device performance. Attached Figure Description

[0020] Figure 1 , Figure 2 IV curves of batteries obtained in each embodiment and comparative example;

[0021] Figure 3 SEM image of the perovskite film after crystallization in Example 4;

[0022] Figure 4 SEM image of the perovskite film after crystallization in Comparative Example 1;

[0023] Figure 5 The proton NMR spectrum of compound 1;

[0024] Figure 6 The proton NMR spectrum of compound 2;

[0025] Figure 7 The proton NMR spectrum of compound 3;

[0026] Figure 8 Infrared spectra of compounds I, II, and III. Detailed Implementation

[0027] The present invention is described in more detail below, but it should not be construed as limiting the scope of protection of the invention to the following description. Unless otherwise specified, any range described in the present invention includes end values, any values ​​between end values, and any sub-ranges formed by end values ​​or any values ​​between end values. There are no particular limitations on the purity of any raw materials used in the present invention; however, analytical grade materials are preferred. The sources and abbreviations of all raw materials used in the present invention are conventional sources and abbreviations in the art, and are clearly understood within the scope of their relevant uses. Those skilled in the art can obtain them from commercially available sources or prepare them using conventional methods based on the abbreviations and corresponding uses.

[0028] "At least one" means one or more, while "more" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0029] Perovskite solar cells include pin-type and nip-type structures. A single-junction perovskite solar cell structure consists of a substrate layer, a transparent conductive layer, a hole transport layer, a perovskite film layer, an electron transport layer, and an electrode layer. The perovskite film layer is the core of the entire device, responsible for absorbing light energy and generating electron-hole pairs. The separation, collection, and flow of these electron-hole pairs are the source of electrical energy. Specifically, when sunlight enters from the transparent conductive layer side and reaches the perovskite film layer, most of the light energy is absorbed. Electrons absorb the energy of photons and undergo band transitions, forming electron-hole pairs. Due to the selective characteristics of the hole transport layer and the electron transport layer, holes migrate from the perovskite film layer to the hole transport layer, while electrons migrate in the opposite direction to the electron transport layer. Holes and electrons flow into their respective transport layers and are further collected by their corresponding electrodes. In the pin structure, electrons flow to the back electrode layer, and holes flow to the transparent conductive layer and are collected at the electrodes.

[0030] Perovskite materials are represented by the general formula [A][B][X]3, where [A] is at least one monovalent cation, such as MA. + FA + Cs + 、Rb + [B] is at least one divalent cation, such as Ca.2+ Pb 2+ Sn 2+ Cu 2+ Ga 2+ And [X] is at least one anion, such as I - ,Br - Cl - F - SCN - When a perovskite includes more than one type of A cation, the different A cations can be distributed at the A sites in an ordered or disordered manner. Similarly, when a perovskite includes more than one type of B cation, the different B cations can be distributed at the B sites in an ordered or disordered manner. Likewise, when a perovskite includes more than one type of X anion, the different X anions can be distributed at the X sites in an ordered or disordered manner.

[0031] The compound used for hole transport in this invention has the following structural formula:

[0032] Structure 1.

[0033] In structural formula one, positions R1-R6 can be independently selected with or without substituents. That is, any position among R1-R6 can be either unsubstituent or substituent. Unsubstituent means that the hydrogen atom on the corresponding carbon atom at that position is not substituted, while substituent means that at least one hydrogen atom on the corresponding carbon atom at that position is substituted. The substituents at positions R1-R6 are independently selected from one or more combinations of alkyl, alkyl derivatives, sulfonic acid groups, alkoxy groups, aromatic groups, aromatic derivatives, carboxylic acid groups, phosphate groups, hydroxyl groups, mercapto groups, amino groups, amino derivatives, halogen groups, and cyano groups. The alkyl groups mentioned include chain alkyl and cyclic alkyl groups. Chain alkyl can be long-chain or short-chain alkyl. Short-chain alkyl refers to alkyl with two or fewer carbon atoms in its carbon chain, such as methyl and ethyl. Long-chain alkyl refers to alkyl with three or more carbon atoms in its carbon chain, preferably long-chain alkyl with three or four carbon atoms in its carbon chain. Alkyl groups can improve the solubility and hydrophobicity of compounds. When used as hole transport layer materials, these compounds are beneficial for isolating perovskite materials from water and oxygen corrosion, thus extending device lifespan. Sulfonic acid groups contain -SO3H, such as -CH2-CH2-SO3H, -C6H4-SO3H, -SO3H, etc., with -SO3H being preferred. Using sulfonic acid-containing molecules as hole transport layer materials helps enhance the dipole at the interface between the hole transport layer and the perovskite film, modulating their energy levels and thereby enhancing hole transport efficiency at the interface. Alkoxy groups contain -OC n H 2n+1 Groups, such as -OC n H 2n+1 -CH2-OC n H 2n+1 etc., preferred -OCn H 2n+1 When alkoxy-containing molecules are used as hole transport layer materials, they can improve the solubility of the material, facilitating its dispersion in solution and film formation on conductive substrates. This, in turn, enhances the uniformity of the hole transport layer and reduces defect formation. Aromatic groups and their derivatives refer to phenyl, naphthyl, and their derivatives, such as... , , , Materials containing aromatic groups have a high degree of conjugation. When these molecular materials are used as hole transport materials, the aromatic groups can form a conjugated system with the conjugated structures in the main molecular structure, enhancing electron transport capability and thus improving the photoelectric conversion efficiency of optoelectronic devices. Carboxylic acid groups refer to groups containing -COOH, such as -CH2-CH2-COOH, -COOH, etc. When molecular materials contain carboxylic acid groups, they can coordinate with metal cations on the conductive substrate surface as hole transport materials, improving the adhesion and stability of the hole transport layer, thereby enhancing device stability. Phosphate groups refer to groups containing -PO(OH)2, such as -C6H4-P(OH)2, -PO(OH)2, etc. When used as hole transport materials, they can form multiple coordination bonds with metals on the conductive substrate surface, enhancing the bonding strength between the hole transport layer and the conductive substrate. Simultaneously, the interaction between phosphate groups helps molecules to arrange themselves in an orderly manner on the substrate, forming a more uniform monomolecular structure and improving hole transport efficiency. Hydroxyl groups, such as -CH2-CH2-OH, -CH2-OH, and -OH, are used as hole transport materials. When used, they interact with halide ions in perovskite, passivating grain boundaries and suppressing vacancy defects, thus optimizing the crystallinity of the perovskite and improving photoelectric conversion efficiency. Thiol groups, such as -CH2-SH and -SH, can coordinate with metal oxides on the ITO substrate surface to form stable chemical bonds, thereby improving the connection stability between the hole transport layer and the substrate. Amino groups, such as -NH3, are derivatives of amino groups where at least one hydrogen atom is replaced by another group, such as -NH2Cl and -CH2-NH2Cl. The combination of amino groups with structural formulas gives compounds electron-donating capabilities, regulating molecular electronic properties. When used as hole transport layer materials, these compounds interact with halogens in perovskite, improving interfacial charge transport efficiency; simultaneously, amino groups can increase the crystallinity of perovskite, enhancing device performance. A cyano group refers to a group containing -CN, such as -CH2-CH2-CN or -CN. A cyano group can enhance the dipole moment of a molecule. When this compound is used as a hole transport material, it can enhance the bonding strength between the hole transport layer and the perovskite and conductive substrate, thereby improving device stability.

[0034] When there are no substituents at positions R1-R6, the structural formula is:

[0035] . When there are no substituents at positions R3 and R4, and the substituents at positions R1, R2, R5, and R6 are -OH, the structural formula is:

[0036] . When there are no substituents at positions R1 and R6, R3 and R4 are -OH, and R2 and R5 are halogen groups -Cl, the structural formula is:

[0037] .

[0038] As a feasible option, R1 is selected from short-chain alkyl groups, -SO3H, and -OC. n H 2n+1 The combination of one or more of the benzene ring groups, where one refers to R1 being a short-chain alkyl group or -SO3H or -OC. n H 2n+1 Or a benzene ring; the combination of multiple elements refers to the presence of short-chain alkyl groups, -SO3H, -OC. n H 2n+1 Two or more of the benzene ring, such as the combination of the benzene ring with -SO3H to form -C6H4-SO3H. This configuration can improve the solubility and hydrophobicity of the molecule, enhance the interfacial dipole, regulate the energy level, improve molecular solubility, facilitate molecular dispersion and film formation in solution, increase the degree of molecular conjugation, and improve electron transport capability. R2 is selected from -OC n H 2n+1 The radical group (-Si-OC), including phenyl ring group, -COOH, long-chain alkyl group, and -PO(OH)2, can be any one of these groups or a combination of two or more. This configuration is beneficial for improving the solubility of the molecule, enhancing film-forming properties, regulating the electronic properties of the molecule, optimizing energy level matching, reducing interfacial defect states, enhancing the conjugation of the molecule, increasing molecular rigidity, and promoting the formation of an ordered molecular arrangement. R3 is selected from siloxane groups (-Si-OC). n H 2n+1 The following groups (n≥1), long-chain alkyl groups, -COOH, -PO(OH)2, -OH, -SH, -F, -Cl, -Br, can be any one of these groups or a combination of two or more of them. This configuration is beneficial for regulating intermolecular interactions, improving the compactness of perovskite films, reacting with hydroxyl groups on the substrate surface to form silicon-oxygen bonds, improving the adhesion and stability of molecules on the conductive substrate, promoting the ordered arrangement of molecules, forming a uniform monomolecular structure on the conductive substrate, facilitating the interaction between the film layer and halide ions in the perovskite, passivating grain boundaries and suppressing the formation of vacancy defects, optimizing the crystallinity of the perovskite, optimizing energy level matching, and improving charge transfer efficiency at the interface. R4 is selected from -COOH, -C n H 2n+1R5 is selected from -PO(OH)2, -F, -Cl, -Br, or long-chain alkyl groups, and can be any one of these groups or a combination of two or more groups. This configuration is beneficial for enhancing the hydrophobicity of molecular materials, improving humidity stability, increasing the crystallinity of perovskite, and improving device performance. R6 is selected from -OC n H 2n+1 -CN, -PO(OH)2, -F, -Cl, -Br, long-chain alkyl, and benzene ring groups can be any group or a combination of two or more groups. This configuration is beneficial for regulating intermolecular interactions, improving the compactness of perovskite films, increasing molecular conjugation, enhancing intermolecular π-π stacking, increasing molecular rigidity, improving the thermal and chemical stability of the SAM layer, reducing interface defect density, and improving device performance.

[0039] As a feasible preferred embodiment, R1 and R6 are the same; R2 and R5 are the same. R1 and R6 are both alkoxy groups; R2 and R5 are both hydroxy groups; R3 is a mercapto group and / or a carboxylic acid group; R4 is an amino group and / or a hydroxyl group. The following are the molecular structural formulas of example compounds one through twenty, in order:

[0040] , ,

[0041] ,

[0042] ,

[0043] ,

[0044] ,

[0045] ,

[0046] , , ,

[0047] , , , .

[0048] The compound mentioned in this invention for transporting holes can be used as a hole transport material in the hole transport layer of optoelectronic devices. Optoelectronic devices can be photovoltaic devices, light-emitting devices, etc. The following mainly describes the application of this compound in photovoltaic devices, using this compound to prepare a hole transport layer for transporting or extracting holes. The hole transport layer may contain only this type of compound, or it may contain this type of compound and other materials. For example, this type of compound can be combined with traditional hole transport materials to form a hole transport layer, or this type of compound can be mixed with additives and passivating agents to prepare a hole transport layer. The aforementioned compound can be a single compound, such as containing only compound one, or it can contain two compounds, such as containing compound two and compound three, or it can contain multiple compounds, such as containing compound one, compound two, and compound three. The substances corresponding to compound one, compound two, and compound three will be given in the examples section.

[0049] When the optoelectronic device is a perovskite solar cell, it can be a single-junction cell or a tandem cell. The perovskite cell structure can be an inverted structure or a conventional structure, and the tandem cell can be a calcium-calcium tandem, a calcium-silicon tandem, etc. The fabrication method of perovskite solar cells is as follows:

[0050] (1) Obtain a substrate, which can be indium tin oxide, fluorine-doped tin oxide transparent conductive glass, or crystalline silicon bottom cell.

[0051] (2) A hole transport layer is deposited on the substrate by solution spin coating. The hole transport layer material is the compound shown in structural formula 1.

[0052] (3) A perovskite film is formed by depositing perovskite material on the hole transport layer. The deposition method is coating or vacuum evaporation. The perovskite film material is a component that can form ABX3, wherein A is an organic cation or an inorganic cation or an organic-inorganic cation, B is a divalent metal cation, and X is a halogen. Preferably, A is an organic-inorganic cation, B is lead ion, and X is two or more halogens.

[0053] (4) A modification layer is formed by depositing a modification layer material on the perovskite film.

[0054] (5) Deposit an electron transport layer on the modification layer by coating or vacuum evaporation. The electron transport layer material is fullerene and its derivatives, tin dioxide or titanium dioxide.

[0055] (6) Electrode material is deposited on the electron transport layer to form a metal electrode with a thickness of 100~200 nm. The deposition method is vacuum evaporation.

[0056] More specific preparation methods will be described in the embodiments. The device in this invention can be a photovoltaic module, photovoltaic equipment, display screen, etc., and is made using the aforementioned optoelectronic devices. Photovoltaic equipment includes photovoltaic panels, photovoltaic wearable devices, photovoltaic vehicles, etc.

[0057] The following description uses specific examples to illustrate the concept.

[0058] Example 1

[0059] The structural formula of the compound used to transport holes is:

[0060] Compound 1.

[0061] The method for synthesizing this compound is as follows:

[0062]

[0063]

[0064] 1. Synthesis of heterocyclic molecular intermediate A containing phenylthio group

[0065] (1) Add 12.7 g of 4-methoxy-2-aminothiophene, 18.7 g of 2-bromophenyl sulfide and 13.8 g of potassium carbonate to a 100 mL round-bottom flask, add DMF and stir to dissolve.

[0066] (2) The raw material was heated in an oil bath at 60 ℃ and refluxed for 4 hours. The raw material disappeared by TLC (developing solvent: ethyl acetate / petroleum ether = 1:3).

[0067] (3) After the reaction solution is cooled, it is poured into 200 mL of ice water, and the solid is precipitated. The solid is filtered, washed with water, and dried to obtain thiophene-amino intermediate A containing phenylthio group.

[0068] 2. Synthesis of intermediate B containing polythiophene conjugated chains

[0069] (1) Add 25.4 g intermediate A, 26.8 g 2,5-dibromo-3-methoxythiophene, 2.3 g Pd(PPh3)4, and 10.1 g triethylamine to the flask, add tetrahydrofuran (THF), and protect with nitrogen.

[0070] (2) Reflux at 80 °C for 6 hours, and monitor the reaction by TLC.

[0071] (3) The solvent was removed by vacuum distillation, and the product was purified by silica gel column chromatography (developing solvent: dichloromethane / methanol = 10:1) to obtain polythiophene conjugated chain intermediate B.

[0072] 3. Introduction of phenothiazine unit

[0073] (1) Add 38.1 g intermediate B, 10.5 g 10H-phenthiazine-2-amine and 0.95 g p-toluenesulfonic acid to a flask, dissolve in 50 mL toluene, reflux for 4 hours using a water separator to remove the water produced in the reaction.

[0074] (2) After cooling, wash twice with saturated sodium carbonate solution, dry the organic phase with anhydrous sodium sulfate, and evaporate the solvent.

[0075] (3) Column chromatography (developing solvent: dichloromethane) was used to purify the conjugated macromolecular intermediate C containing phenothiazine.

[0076] 4. Connecting the -SH and -NH2 sites yields intermediate D.

[0077] (1) Add 48.6 g of intermediate C and 3.8 g of thiourea to 50 mL of ethanol, reflux for 2 h, add 20 mL of 1 mol / L hydrochloric acid and continue reflux for 1 h (thiourea is hydrolyzed by hydrochloric acid to -SH).

[0078] (2) Add 2.7 g of ammonium chloride and heat at 80 °C for 3 h to introduce -NH2.

[0079] (3) After cooling, adjust the pH of the reaction system to 7, filter and dry to obtain conjugated chain intermediate D containing -SH and -NH2.

[0080] 5. Connect the phosphonate side chain to obtain the final product.

[0081] (1) Add 50 g of product D, 8.2 g of allyl phosphate diester, 12.5 g of 3-bromopropyl phosphate diester and 0.8 g of azobisisobutyronitrile to a flask, dissolve in 50 mL of dichloromethane, and heat and stir at 50 °C for 6 h in a nitrogen atmosphere.

[0082] (2) Remove solvent by vacuum distillation and purify by silica gel column chromatography (developing solvent: dichloromethane / methanol = 8:1).

[0083] (3) Vacuum drying yields the final product.

[0084] The final product's 1H NMR spectrum and FIR spectrum are as follows: Figure 4 and Figure 7 As shown, analysis reveals that the final product of this embodiment is the desired target compound, namely compound one.

[0085] Example 2

[0086] The compound used for hole transport has the following structural formula:

[0087] Compound 2.

[0088] The synthesis method of compound 2 is as follows:

[0089]

[0090]

[0091] 1. Construct intermediate A containing thiophene-ethoxy groups.

[0092] (1) Add 0.13 g (1.1 mmol) 2-hydrazylthiophene and 0.02 g p-toluenesulfonic acid to a dry 25 mL round-bottom flask, and then inject 5 mL of anhydrous ethanol.

[0093] (2) A reflux condenser was installed in a round-bottom flask. The reaction system was heated to 80 °C in an oil bath and the reaction solution was refluxed for 6 h with vigorous stirring (TLC monitoring: petroleum ether / ethyl acetate = 3:1).

[0094] (3) After the reaction was completed, the ethanol was removed by rotary evaporation at 40 °C and 100 mbar. The residue was dissolved in 10 mL of ethyl acetate and washed with 10 mL of water to remove water-soluble impurities.

[0095] (4) The organic phase was dried with anhydrous sodium sulfate for about 5 min, filtered and concentrated by rotary evaporation, and then subjected to column chromatography (eluent: petroleum ether / ethyl acetate = 3:1). The fraction with Rf = 0.4 was collected and dried by rotary evaporation to obtain about 0.18 g of intermediate A containing thiophene-ethoxy group, with a yield of 85%, which was stored in a dry sample bottle for later use.

[0096] 2. Introducing a phosphate ester side chain yields product B.

[0097] (1) Dry a 10 mL round-bottom flask, add 0.15 g formylmethylphosphonic acid (1.0 mmol), 0.23 g EDCI (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide) (1.2 mmol), 0.015 g HOBt (hydroxybenzotriazole) (0.1 mmol), inject 3 mL of anhydrous DMF, stir at room temperature for 15 min to activate the carboxyl group.

[0098] (2) Add 0.21 g of intermediate A (1.0 mmol), seal the flask, and stir at room temperature for 24 h until the reaction is complete. The reaction was monitored by TLC: dichloromethane / methanol = 20:1, Rf = 0.3.

[0099] (3) Quench the reaction solution with 5 mL of deionized water, extract with ethyl acetate 3 times, 10 mL of ethyl acetate each time, combine the organic phases, wash with water 2 times, 5 mL of water each time, dry with anhydrous sodium sulfate, and concentrate by rotary evaporation.

[0100] (4) Column chromatography (stationary phase: silica gel 60 mesh; eluent: dichloromethane / methanol = 20:1), collect the fraction with Rf = 0.3, evaporate to dryness to obtain product B about 0.28 g, yield 78%, for later use.

[0101] 3. Introducing a polyhydroxyphosphonate fragment to obtain product C

[0102] (1) Dry a 10 mL round-bottom flask, add 0.36 g (1.0 mmol) of product B, 0.16 g (1.1 mmol) of dihydroxymethylphosphonic acid, and 0.012 g (0.1 mmol) of DMAP, inject 5 mL of anhydrous dichloromethane, and cool to 0 °C in an ice bath.

[0103] (2) Add 0.25 g (1.2 mmol) DCC (dicyclohexylcarbodiimide) in batches, keep at 0 ℃ and stir for 30 min, then raise to room temperature and stir for 12 h to finish the reaction. The reaction was monitored by TLC: ethyl acetate / methanol = 10:1, Rf = 0.4.

[0104] (3) Filter to remove white solid DCU (dicyclohexylurea), concentrate the filtrate by rotary evaporation, and perform column chromatography (stationary phase: silica gel 60 mesh; eluent: ethyl acetate / methanol = 10:1). Collect the fraction with Rf = 0.4 and evaporate to dryness to obtain product C (about 0.42 g, yield 82%) for later use.

[0105] 4. Introduce bromophosphonate to obtain the final molecule.

[0106] (1) Dry a 25 mL round-bottom flask, add 0.51 g (1.0 mmol) of product C obtained in step 3, 0.20 g (1.1 mmol) of 2-bromoethylphosphonic acid, and 0.28 g (2.0 mmol) of anhydrous potassium carbonate, and inject 5 mL of anhydrous acetonitrile.

[0107] (2) Install a reflux condenser on a round-bottom flask, heat the reaction system to 80 °C in an oil bath, stir and reflux for 10 h to finish the reaction, and monitor the reaction by TLC: petroleum ether / ethyl acetate = 1:1, Rf = 0.5.

[0108] (3) After the reaction is completed, the reaction solution is cooled to room temperature, filtered to remove inorganic salts, the filtrate is concentrated by rotary evaporation, and column chromatography is performed (stationary phase: silica gel 60 mesh; eluent: petroleum ether / ethyl acetate = 1:1). The fraction with Rf = 0.5 is collected and evaporated to dryness to obtain the final product of about 0.55 g, with a yield of 85%.

[0109] The final product's 1H NMR spectrum and FIR spectrum are as follows: Figure 5 and Figure 8 As shown, analysis reveals that the final product of this embodiment is the desired compound two.

[0110] Example 3

[0111] The structural formula of the compound used to transport holes is:

[0112] Compound 3.

[0113] The synthesis method of compound 3 is as follows:

[0114]

[0115] Amidation reaction of 1,2-aminopyrimidine with N-chlorosuccinimide

[0116] (1) Add 0.951 g of 2-aminopyrimidine to a dry round-bottom flask, inject 10 mL of anhydrous DCM, stir to dissolve, and then cool the reaction system to 0 °C using an ice bath.

[0117] (2) Slowly add 10 mL of DCM solution containing 1.711 g N-chlorosuccinimide to the reaction system while stirring.

[0118] (3) After the droplets are finished, remove the ice bath and stir the reaction at room temperature for 5 h. The reaction is monitored by TLC: the developing solvent is petroleum ether / ethyl acetate, and the color is developed by UV lamp or colorimetric reagent.

[0119] (4) The reaction solution was washed with saturated NaHCO3 solution to neutralize HCl. The organic phase was separated and dried with anhydrous Na2SO4. The solvent was removed by rotary evaporation to obtain intermediate A of the first step, with a yield of 85%.

[0120] 2. The amide intermediate undergoes an amide condensation reaction with NOTA-C6-amine to yield intermediate B.

[0121] (1) Add intermediate A, NOA-C6-amine, EDC・HCl and HOBt to a round-bottom flask, inject 15 mL of anhydrous DMF, and stir at room temperature for 15 min to obtain the reaction system.

[0122] (2) The reaction system was stirred at room temperature for 14 h to finish. The reaction was monitored by TLC: the developing solvent was petroleum ether / ethyl acetate, and the color was developed by UV lamp or colorimetric reagent.

[0123] (3) Pour the reaction solution into 50 mL of ice water, stir to precipitate solid, filter, wash the filter cake with a small amount of water, and vacuum dry to obtain about 0.0068 mol of intermediate B in the second step, with a yield of 80%.

[0124] 3. The oxime reaction of the heterocyclic intermediate with hydroxylamine yields intermediate C.

[0125] (1) Add intermediate B, hydroxylamine hydrochloride and triethylamine to a round-bottom flask, inject 20 mL of anhydrous ethanol, heat and reflux for 3 h, and monitor with TLC.

[0126] (2) After cooling, remove ethanol by rotary evaporation. Add 20 mL of water to the residue and extract the organic phase three times with ethyl acetate, each time using 15 mL of ethyl acetate. Combine the organic phases, dry with anhydrous Na2SO4, and remove the solvent by rotary evaporation to obtain the crude product.

[0127] (3) The crude product was separated by column chromatography (eluent: petroleum ether / ethyl acetate = 1:2) to obtain approximately 0.0051 mol of the third intermediate C, with a yield of 75%.

[0128] 4. Heterocyclic splicing reaction yields the final molecule.

[0129] (1) Add intermediate C, 2-amino-1,4-naphthoquinone and p-toluenesulfonic acid to a round-bottom flask, inject 20 mL of anhydrous toluene, heat and reflux for 6 h, and monitor with TLC.

[0130] (2) After cooling, filter to remove insoluble matter, and remove toluene by rotary evaporation to obtain crude product.

[0131] (3) The crude product was recrystallized from ethanol / water (5:1), filtered, and dried to obtain approximately 4.0 g of final molecules, with a yield of 70%.

[0132] The final product's 1H NMR spectrum and FIR spectrum are as follows: Figure 6 and Figure 8 As shown, analysis reveals that the final product of this embodiment is the desired compound three.

[0133] Example 4

[0134] This embodiment describes the fabrication of a single-junction perovskite solar cell with an inverted bandgap of 1.68 eV using Compound 1. The fabrication method includes the following steps:

[0135] S01 Obtain the substrate

[0136] Using ITO glass as the substrate, the ITO glass substrate is first ultrasonically cleaned in a cleaning agent for 30 minutes, then ultrasonically cleaned in deionized water for 20 minutes, and finally ultrasonically cleaned in isopropyl alcohol (IPA) for 20 minutes. After that, it is dried with a nitrogen gun and placed in a UV ozone processor for 15 minutes for later use.

[0137] S02 is used to prepare the hole transport layer.

[0138] (1) The compound obtained in Example 1 was dissolved in ethanol at a concentration of 1 mg / mL to form an ethanol solution of compound 1. Then, a 0.45 μm filter was used to filter out large particles. The filtered solution was a hole transport layer solution.

[0139] (2) The hole transport layer solution was spin-coated onto ITO glass at a spin rate of 4000 rpm for 30 s.

[0140] (3) Anneal at 120 °C for 10 min to obtain a uniformly distributed hole transport layer.

[0141] Preparation of S03 perovskite film

[0142] (1) Preparation of perovskite solution: 548.59 mg of PbI2, 28.31 mg of MABr, 22.1 mg of CsI, 232.56 mg of FAI and 187.17 mg of PbBr2 were dissolved in 0.80 mL of DMF (NN dimethylformamide) and 0.2 mL of DMSO (dimethyl sulfoxide). The solution was heated and stirred at 60 °C for 2 hours until completely dissolved. The solution was then filtered through a 0.45 μm organic filter to remove larger particles, yielding 1.7 M FAI. 0.8 MA 0.15 Cs 0.05 Pb(I) 0.75 Br 0.25 )3 solution.

[0143] (2) The prepared perovskite solution was spin-coated onto the hole transport layer at a spin-coating rate of 4000 rpm for 30 s. At the 18th s of spin-coating, 150 μL of the antisolvent toluene was uniformly added to the film. Then, the film was annealed at 100 °C for 30 min under a nitrogen atmosphere and cooled for later use to form a perovskite film with a thickness of 450 nm.

[0144] Preparation of S04 Modified Layer

[0145] (1) Preparation of ethylenediamine dihydroiodate (EDAI2) solution: Dissolve 0.5 mg of EDAI2 in 1 mL of isopropanol, shake and stir to form an isopropanol solution of 0.5 mg / mL EDAI2, and filter the solution with a 0.45 μm filter to remove larger particles and obtain EDAI2 solution.

[0146] (2) The EDAI2 solution was spin-coated onto the perovskite film at a speed of 3000 rpm for 30 s, and then annealed at 100°C in a nitrogen atmosphere for 5 minutes to form a modified layer with a thickness of about 3 nm.

[0147] Preparation of S05 electron transport layer

[0148] Vacuum evaporation equipment is used to evaporate C using a thermal evaporation method. 60 The material forms a 20 nm electron transport layer on the modified perovskite film, with a deposition vacuum of 6*10⁻⁶. -4 Below Pa.

[0149] Preparation of S06 barrier layer:

[0150] Using vacuum evaporation equipment, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline or copper bath) material was evaporated by thermal evaporation to form a 10 nm barrier layer on the electron transport layer. The evaporation vacuum degree was 6*10 -4 Below Pa.

[0151] Preparation of S07 electrode

[0152] A 100 nm layer of silver (Ag) was deposited on the surface of the barrier layer using thermal evaporation as an electrode.

[0153] The desired perovskite solar cell was obtained.

[0154] Example 5

[0155] The difference between Example 5 and Example 4 lies in the hole transport material and the perovskite composition. In Example 5, Compound 2 was used as the hole transport layer material to prepare the hole transport layer. The preparation method was the same as in Example 4, and the perovskite composition was 1.5 MFA. 0.75 Cs 0.25 Pb(I 0.8 Br 0.2 3. The detailed preparation process of the perovskite is as follows: 484.05 mg of PbI2, 97.5 mg of CsI, 128.25 mg of FAI, and 165.15 mg of PbBr2 are dissolved in 0.80 mL of DMF and 0.2 mL of DMSO. The solution is stirred overnight at room temperature in a glove box until completely dissolved, and then filtered using a 0.22 μm organic filter cartridge to remove larger particles. Other steps are the same as in Example 4.

[0156] Example 6

[0157] The difference from Example 4 lies in the hole transport material and the perovskite film preparation process. In Example 6, compound 3 was used as the hole transport layer material to prepare the hole transport layer, and the preparation method was the same as in Example 4.

[0158] The perovskite film was applied using a two-step spin-coating method:

[0159] (1) A solution was prepared by taking 589.6 mg PbI2, 155.5 mg PbBr2, 0.9 mL DMF and 0.1 mL DMSO, and heated and stirred at 60 °C for 12 h to obtain lead source precursor solution A;

[0160] (2) Add 235.5 mg FAI, 41.3 mg MAI and 21.9 mg CsI to 1 mL of IPA solvent and stir at room temperature for 4 h to obtain precursor solution B.

[0161] (3) First, take 80 μL of precursor solution A and add it to the hole transport layer for spin coating. 20 s before the end of spin coating, add 100 μL of CB as an anti-solvent, and then anneal at 70 °C for 10 min.

[0162] (4) Then take 100 μL of precursor solution B, add it dropwise and spin coat it. After spin coating, anneal it on an annealing table at 150 °C for 30 min to obtain a complete perovskite film.

[0163] The remaining steps are the same as in Example 4.

[0164] Example 7

[0165] This embodiment describes the fabrication of a perovskite / silicon tandem solar cell using Compound III. The perovskite layer has a band gap of 1.68 eV. The fabrication method includes the following steps:

[0166] S01 Obtain the substrate

[0167] Heterojunction silicon wafers were used as the substrate for the tandem solar cells. The substrate dimensions were 2.5 cm x 2.5 cm. The substrate was placed face up and treated with ultraviolet ozone for 20 minutes before use.

[0168] S02 is used to prepare the hole transport layer.

[0169] (1) Dissolve compound 3 in anhydrous ethanol at a concentration of 1 mg / mL to form an ethanol solution of compound 3. Then filter it with a 0.45 μm organic filter head to remove large particulate impurities. The filtered solution is a hole transport layer solution.

[0170] (2) Spin-coating the hole transport layer solution onto the silicon substrate at a spin rate of 3000 rpm for 35 s;

[0171] (3) Anneal at 100 °C for 10 min to obtain a uniformly distributed hole transport layer.

[0172] Preparation of S03 perovskite film

[0173] The preparation method of the perovskite film is the same as that in Example 4, except that the antisolvent is replaced by chlorobenzene instead of toluene, and the amount of chlorobenzene used is 180 μL.

[0174] Preparation of S04 Modified Layer

[0175] (1) Preparation of phenylethyl ammonium iodide (PEAI) solution: Dissolve 1 mg of PEAI in 1 mL of isopropanol, shake and stir to form an isopropanol solution of 1 mg / mL PEAI, and filter the solution with a 0.45 μm filter to remove larger particles and obtain PEAI solution.

[0176] (2) Spin-coat the PEAI solution onto the perovskite film at a speed of 4000 rpm for 27 s, and then anneal it in a nitrogen atmosphere at 100°C for 10 min to form a modified layer with a thickness of about 4 nm.

[0177] Preparation of S05 electron transport layer

[0178] Vacuum evaporation equipment is used to evaporate C using a thermal evaporation method. 60 The material forms a 20 nm C layer on the modified perovskite film. 60 Electron transport layer, vapor deposition vacuum degree is 6*10 -4 Below Pa.

[0179] Preparation of S06 buffer layer:

[0180] A 20 nm thick SnO2 layer was prepared using atomic layer deposition (ALD) as a buffer layer to prevent the electrode from eroding the underlying film.

[0181] Preparation of S07 transparent electrode

[0182] 30 nm IZO material was sputtered onto the buffer layer as a transparent electrode using magnetron sputtering, with a magnetron power of 30-200 W.

[0183] Preparation of S08 electrode

[0184] A 300 nm layer of silver (Ag) was deposited on the surface of a transparent electrode using thermal evaporation as the electrode, and a 300 nm layer of Ag was deposited on the back of the battery as the back electrode. The vacuum level was maintained at 6*10⁻⁶ throughout the deposition process. -4 Below Pa.

[0185] To produce the desired perovskite solar cell

[0186] Comparative Example 1

[0187] The only difference between Comparative Example 1 and Example 4 is the hole transport layer material. Comparative Example 1 uses ethyl 2-[(2-chlorophenyl)(phenyl)amino]benzoate (2PACz) as the hole transport material, and the other steps and conditions are the same as in Example 4.

[0188] Comparative Example 2

[0189] The only difference between Comparative Example 2 and Example 7 is the hole transport layer material. Comparative Example 2 uses ethyl 2-[(2-chlorophenyl)(phenyl)amino]benzoate (2PACz) as the hole transport material, and the other steps and conditions are the same as in Example 7.

[0190] The photoelectric conversion efficiency of the perovskite solar cells in Examples 4, 5, and 6, as well as Comparative Example 1, was tested by scanning from a high voltage (1.3 V) to a low voltage (-0.1 V) with a scan step size of 0.1 V and an interval of 20 ms. The conversion power of the cell was obtained by multiplying the voltage and current, and then the conversion efficiency was obtained by combining the incident power of sunlight. Figure 1 It can be seen that the conversion efficiency of perovskite solar cells in Examples 4, 5, and 6 is significantly improved compared with that in Comparative Example 1, indicating that the compound used as SAM material in this invention effectively improves the performance of perovskite solar cells.

[0191] The photoelectric conversion efficiency of the perovskite / silicon tandem solar cells in Example 7 and Comparative Example 2 was tested using a standard parameters: a current range of 0.05 A, a voltage range of 2.5 V, a test interval of 5 s, a data volume of 100, a pre-illumination time of 3000 ms, and a scan time of 3000 ms. The conversion power of the cell was obtained by multiplying the voltage and current, and then the conversion efficiency was obtained by combining the incident sunlight power. Figure 2 As can be seen, the conversion efficiency of the perovskite solar cell in Example 7 is significantly improved compared to that in Comparative Example 2, indicating that the compound used as a SAM material in this invention effectively improves the performance of perovskite solar cells.

[0192] In addition, from Figure 3 and Figure 4 It can be observed that, compared to Comparative Example 1, the use of Compound 1 in Example 4 reduced the precipitation of lead iodide on the surface of the perovskite film, while the grain size was larger and the size distribution was more uniform. This indicates that the compound in this invention, as a hole transport material, improved the crystallization process of perovskite, formed a higher quality perovskite film, and reduced interface defects.

[0193] Using compound four to compound twenty as hole transport materials in the specific embodiments of the present invention, perovskite single-junction cells were prepared by the method of preparing the cell in Example 4. The efficiency of the prepared cells was 21.17%-22.98%, which was higher than the efficiency of 19.45% of the cell in Comparative Example 1.

[0194] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A compound for use in the transmission of holes for use in the transmission of holes, characterized in that: The structural formula is ； In the formula: R1, R2, R3, R4, R5, R6 are each independently selected from one or more combinations of hydrogen, alkyl, derivative of alkyl, sulfonic acid group, alkoxy, aromatic group, derivative of aromatic group, carboxylic acid group, phosphoric acid group, hydroxyl group, mercapto group, amino group, derivative of amino group, halogen group, and cyano group.

2. The compound for transporting holes according to claim 1, characterized by: said alkyl is -C n H 2n+1 wherein 1 < n < 4.

3. The compound for transporting holes according to claim 1, characterized by: R1 is selected from one or more combinations of alkyl, sulfonic acid group, alkoxy, and aromatic group; R2 is selected from one or more combinations of alkoxy, benzene ring group, carboxylic acid group, and alkyl group; R3 is selected from one or more combinations of siloxane group, alkyl group, carboxylic acid group, phosphoric acid group, hydroxyl group, and mercapto group; R4 is selected from one or more combinations of carboxylic acid group, alkyl group, trifluoromethyl group, hydroxyl group, phosphoric acid group, amino group, and halogen group; R5 is selected from one or more combinations of phosphoric acid group, alkyl group, and halogen group; R6 is selected from one or more combinations of alkoxy, cyano, and benzene ring group.

4. The compound for transporting holes according to claim 1, wherein: R1 and R6 are the same; R2 and R5 are the same.

5. The compound for transporting holes according to claim 1, characterized by: R1 and R6 are both alkoxy; R2 and R5 are both hydroxyl; R3 is mercapto or / and carboxylic acid; and R4 is amino or / and hydroxyl.

6. The compound for transporting holes according to claim 1, wherein: The structural formula is: 、 、 、 、 、 、 、 、 、 、 、 。 7. An optoelectronic device, characterized by: The compound for transporting holes according to any one of claims 1-6.

8. An optoelectronic device as claimed in claim 7, characterized in that: The photoelectric device is a perovskite battery, which comprises a hole transport layer, a perovskite film layer, and an electron transport layer. The perovskite film layer generates free electrons and holes under light laser state. The free electrons enter the electron transport layer, and the holes enter the hole transport layer. The hole transport layer contains the compound for transporting holes according to any one of claims 1-6.

9. The device of claim 7, wherein: Further comprising a conductive substrate, wherein the hole transport layer is arranged on the conductive substrate, and the conductive substrate is conductive glass, conductive PVC, a silicon battery sheet, or a thin film battery sheet; a modification layer, wherein the modification layer is arranged between the perovskite film layer and the electron transport layer, and the material of the modification layer is EDAI2; an electrode layer, wherein the electrode layer forms a counter electrode with the conductive substrate, so that the device forms a battery; the perovskite film layer and the hole transport layer are both prepared by a solution method.

10. The device of claim 7, wherein: The perovskite film layer material is ABX3, A is FA + , MA + , and Cs + , B is Pb 2+ , and X is I - and Br - .

Images