Perovskite photovoltaic device, preparation method and hole transport material

Abstract

The invention relates to a perovskite photovoltaic device, a preparation method and a hole transport material, the perovskite photovoltaic device comprises a hole transport layer, a perovskite layer and an electron transport layer, the perovskite layer generates free electrons and holes in a light excitation state, the free electrons enter the electron transport layer, the holes enter the hole transport layer, and the hole transport layer is formed by the free electrons and the holes. The hole transport layer contains an organic material M, and the structural formula of the organic material M is shown in the specification; the new hole transport material is introduced to serve as the hole transport layer of the perovskite photovoltaic device, a smooth hole transport channel is constructed, the carrier transport efficiency is improved, the perovskite material is guided to form a film through the hole transport material, molecular agglomeration in the film forming process is avoided, and the film forming quality and the device stability are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a perovskite photovoltaic device, a preparation method and a hole transport material, and belongs to the photovoltaic field. BACKGROUND

[0002] The overexploitation and consumption of fossil energy continue to exacerbate the global climate crisis, and accelerating the transformation to clean energy has become a common consensus in the entire society. In recent years, major economies have formulated renewable energy development strategies to promote the large-scale application of green energy technologies such as solar, wind, water and tidal energy, and the proportion of clean energy in the global energy structure continues to increase. As the most abundant renewable energy, solar energy has shown great development potential. The energy radiated by the sun to the earth per second is about 800,000 kilowatts, and the annual cumulative energy is equivalent to the total energy released by the burning of 130 trillion tons of standard coal. If 0.013% of the solar energy can be effectively converted and utilized, it can fully meet the current energy needs of human society. As the core technology of solar energy development, traditional photovoltaic technology based on silicon is becoming more and more mature, but its large-scale commercial application faces challenges such as high cost, complex process and serious pollution. Under this background, perovskite photovoltaic technology has rapidly risen in recent years due to its simple preparation process, low cost characteristics, flexible preparation and excellent photovoltaic performance, and has become a research hotspot in this field.

[0003] The Shockley-Queisser (S-Q) theoretical efficiency limit of perovskite single-junction cells is 33%. However, the highest efficiency currently published is 27%, which has exceeded traditional crystalline silicon solar cells, but is still far below the theoretical limit, and perovskite cells are prone to aggregation during film formation and have low water vapor resistance, resulting in stability that is not as good as traditional crystalline silicon cells. How to improve the efficiency and stability of perovskite cells is the main problem of current research. SUMMARY

[0004] To solve the above problems, the present application provides a perovskite photovoltaic device, a preparation method and a hole transport material. The present application introduces a new hole transport material as the hole transport layer of the perovskite photovoltaic device, constructs a smooth hole transport channel, improves the carrier transport efficiency, and guides the film formation of the perovskite material through the hole transport material, avoiding molecular aggregation during film formation and improving the film formation quality and device stability.

[0005] One of the technical solutions adopted by the present application is:

[0006] A perovskite photovoltaic device, comprising a hole transport layer, a perovskite layer, an electron transport layer, the perovskite layer generates free electrons and holes under light laser state, the free electrons enter the electron transport layer, the holes enter the hole transport layer, the hole transport layer contains an organic material M, the structural formula of the organic material M is:

[0007]

[0008] In the formula: R1, R4 are each independently selected from one or more combinations of hydrogen atom, sulfide, alkyl, silane group, t-butyl, adamantyl or derivatives thereof; R2, R3 are each independently selected from one or more combinations of hydrogen atom, amino or amino derivatives, halogen, alkyl, aryl; R5, R6 are each independently selected from aryl or derivatives thereof.

[0009] Preferably, the perovskite material in the perovskite layer is ABX3, wherein A is one or more combinations of FA + , MA + , Cs + , B is Pb + , and C is one or more combinations of I - , Br - , Cl - .

[0010] Preferably, the perovskite material ABX3 contains at least FA + or MA + , B is Pb + , and C contains at least I - or Br - .

[0011] Preferably, the hole transport layer is deposited on a substrate, and a metal oxide thin film layer is provided on the side of the substrate connected to the hole transport layer; the perovskite layer is deposited on the hole transport layer, and the hole transport layer is in direct contact with the perovskite layer.

[0012] Preferably, in the structural formula of the organic material M, one of R1 or R4 is a silane group or / and a t-butyl group or / and an adamantyl group, and the other is a methyl group, an ethyl group or a derivative thereof; at least one of R2 or R3 is an amino group or an amino derivative.

[0013] Preferably, a modification layer is provided between the perovskite layer and the electron transport layer, and a hole blocking layer is provided on the side of the electron transport layer opposite to the perovskite layer, the modification layer is PEAI, and the hole blocking layer is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline or bathocuproin.

[0014] The second aspect is a preparation method of a perovskite photovoltaic device, comprising the following steps:

[0015] S01 obtaining a substrate;

[0016] S02 preparing a hole transport layer;

[0017] S03 preparing a perovskite layer, which is a lead-based perovskite material;

[0018] S04 preparing an electron transport layer;

[0019] The hole transport layer is prepared by a solution method, and the preparation method comprises the following steps: a. dissolving a hole transport material in an organic solvent to obtain a hole transport material precursor solution, wherein the concentration of the hole transport material in the hole transport material precursor solution is 0.5-1.5 mg / mL; b. coating the hole transport material precursor solution on the substrate; and c. annealing to form a film.

[0020] The third aspect is a hole transport material for a perovskite photovoltaic device, and the structural formula is:

[0021] ;

[0022] In the formula, R1 and R4 are each independently selected from one or more combinations of a hydrogen atom, a sulfur group, an alkyl group, a silane group, a tert-butyl group, an adamantyl group or derivatives thereof; R2 and R3 are each independently selected from one or more combinations of a hydrogen atom, an amino group or an amino derivative, a halogen, an alkyl group, an aryl group; and R5 and R6 are each independently selected from an aryl group or a derivative thereof.

[0023] As a preference, one of R1 or R4 is a silane group or / and a tert-butyl group or / and an adamantyl group, and the other is a methyl group, an ethyl group or a derivative thereof, and at least one of R2 and R3 is an amino group or an amino derivative.

[0024] The beneficial effects produced by the present application are described in detail in the specific implementation part. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Voltage-current curve diagrams of perovskite batteries obtained in Comparative Example 1, Example 1, Example 2 and Comparative Example 3;

[0026] Figure 2 Voltage-current curve diagrams of perovskite solar cells in Comparative Example 2 and Example 4;

[0027] Figure 3 Surface SEM diagram of the perovskite layer obtained in Comparative Example 1;

[0028] Figure 4 Surface SEM diagram of the perovskite layer obtained in Example 1;

[0029] Figure 5 Infrared spectra of the three materials;

[0030] Figures 6(a), 6(b), and 6(c) are the NMR spectra of materials 1, 2, and 3, respectively. Detailed Implementation

[0031] 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.

[0032] "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.

[0033] Those skilled in the art will understand that perovskite materials are represented by the general formula ABX3, wherein A is at least one monovalent cation, such as MA. + FA + Cs + 、Rb + In this case, 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 A-site cation, the different A-site cations can be distributed at the A-site in an ordered or disordered manner. Similarly, when a perovskite includes more than one B-site cation, the different B-site cations can be distributed at the B-site in an ordered or disordered manner. Likewise, when a perovskite includes more than one X-site anion, the different X-site anions can be distributed at the X-site in an ordered or disordered manner.

[0034] 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 layer, an electron transport layer, and an electrode layer. The perovskite 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 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 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. A tandem perovskite solar cell consists of a bottom cell and a top cell. The bottom cell is a silicon solar cell or a perovskite solar cell, and the top cell is a perovskite solar cell. Its structure includes a hole transport layer, a perovskite layer, an electron transport layer, and electrodes.

[0035] The photovoltaic device in this invention uses a novel hole transport material as the hole transport layer. The hole transport material used is an organic material M, with the following structural formula:

[0036] .

[0037] This material uses dibenzothiophene and carbazole units as dual core functional modules. The rigid conjugated framework of the dibenzothiophene unit and the large π-conjugated system of multiple carbazole units work synergistically to effectively construct a continuous and unobstructed hole transport channel, significantly reducing the charge recombination probability and transport energy barrier during hole transport, thereby improving charge mobility. Furthermore, the structure has six substitution sites, R1-R6, which can be used to introduce sterically hindered groups, coordination groups, and conjugated groups to achieve synergistic effects, making the contact with the perovskite surface more uniform and improving the film quality of the perovskite film. The substitution groups in the structure can effectively passivate defects at the perovskite / hole transport layer interface, ensuring that photogenerated holes can be efficiently transferred from the perovskite layer to the hole transport layer. In the structural formula, R1 and R4 are each independently selected from one or more combinations of hydrogen atom, mercapto, silyl, tert-butyl, adamantyl, short-chain alkyl, and short-chain alkyl derivatives; R2 and R3 are each independently selected from one or more combinations of hydrogen atom, short-chain alkyl, short-chain alkyl derivatives, amino, amino derivatives, halogen, and aryl; R5 and R6 are each independently selected from aryl or its derivatives, and the aforementioned short-chain alkyl is -C. n H 2n+1 1≤n≤3, short-chain alkyl derivatives refer to those with -C n H 2n+1 One or more hydrogen atoms in the group are substituted, such as -CH2Br, -CH2Cl, -CF3; amino derivatives refer to -NH2 where one or two hydrogen atoms are substituted, such as dimethylamino-N(CH3)2, diphenylamino-NPh2. Aryl groups include phenyl, biphenyl, naphthyl, etc.

[0038] Introducing silyl, tert-butyl, or adamantyl groups at positions R1 and / or R4 creates steric hindrance, hindering close molecular packing, preventing molecular aggregation, and improving material thermal stability. Introducing short-chain alkyl groups at these positions slightly increases the molecular electron cloud density and hydrophobicity, reducing water vapor adsorption and enhancing material stability. Introducing amino groups or amino derivatives at positions R2 and / or R3 creates N-Pb coordination bonds with Pb²⁺ on the perovskite surface, effectively passivating interfacial defects between the perovskite and hole transport layer. Introducing halogen atoms modulates the electron cloud distribution of the hole transport material, increases molecular polarity, and enhances the interaction between the molecule and the perovskite. Introducing aryl groups at positions R5 and / or R6 significantly extends the molecular conjugation length, improving hole transport capability.

[0039] In one embodiment, one of R1 or R4 is silyl or / and tert-butyl or / and adamantyl, and the other is methyl, ethyl, or a derivative thereof. The presence of large sterically hindered groups such as silyl or / and tert-butyl or / and adamantyl in the dibenzothiophene and carbazole units, along with small sterically hindered alkyl groups such as methyl and ethyl, can prevent molecular stacking, improving the perovskite film quality, and also prevent the groups from being squeezed into the conjugated structure of the carbazole-thiophene fused ring, affecting the electrical transport efficiency. Furthermore, methyl, ethyl, or their derivatives have moderate hydrophobicity, forming a dual-gradient hydrophobic system, improving the stability of the perovskite battery. Preferably, the small sterically hindered alkyl group is an F or Cl substitute for methyl or ethyl, such as -CH2Cl or -CH2F. At least one of R2 and R3 is amino or an amino derivative, preferably both R2 and R3 are amino or amino derivatives. Dual-amino modification can achieve multi-site synergistic passivation, increasing the passivation site density from 8 × 10¹³ cm⁻³ to 1.5 × 10¹³ cm⁻³. 4 The SAM layer, with a thickness of cm⁻³, simultaneously covers Pb²⁺ vacancies and I⁻ interstitial defects, improving the quality of the perovskite film. Furthermore, the strong electron-donating properties of the diamino groups increase the electron cloud density at the SAM layer interface, enhancing interaction with the electron cloud on the perovskite surface and improving hole transport efficiency. The aryl groups of R5 and R6 can form an "uninterrupted large conjugated framework" with the carbazole-thiophene fused ring structure—holes can be efficiently delocalized and transported within the conjugated system, improving hole mobility.

[0040] In this invention, the perovskite material for the photovoltaic device can be any material that satisfies the ABX3 structure and can generate free electrons and holes under photoexcitation. Preferred perovskite materials are lead-based organic perovskites or lead-based organic-inorganic perovskites, wherein the A-site has a FA structure. + MA + Cs + One or more combinations of these, where the B site is Pb + The X position is I - ,Br - Cl - One or more combinations of these components. This type of perovskite material not only optimizes the light absorption range by controlling the bandgap of the battery through regulating the halogen at the X-site, but also generates fewer defects during the perovskite film formation process. Furthermore, the vacancies or defects generated are easily passivated by the aforementioned hole transport materials, reducing defect density and preventing non-radiative recombination of charge carriers. As a preferred embodiment, the perovskite material ABX3 contains at least FA in A. + or MA + B is Pb + X contains at least I - or Br - When this perovskite material is combined with the aforementioned hole transport material, the energy levels are matched, resulting in extremely low losses during charge transport, which increases the open-circuit voltage. Furthermore, it directionally guides the perovskite film formation, creating a dense, pinhole-free film layer and improving the device's fill factor.

[0041] The substrate in this invention can be conductive glass, conductive PVC, crystalline silicon solar cells, etc. A metal oxide thin film layer, such as an FTO film or an ITO film, is disposed on the substrate for conduction or tunneling. During the fabrication of the perovskite solar cell, a hole transport layer is deposited on the side of the substrate where the metal oxide layer is disposed. One end of the hole transport material containing large π-π bonds is anchored to the substrate, and the other end is connected to the perovskite layer via hydrogen bonds or coordination bonds. This increases the connection strength between the device layers, improves charge transport efficiency, and prevents water and oxygen from entering the hole transport layer, thus improving device stability.

[0042] In this invention, the perovskite photovoltaic device preferably consists of a substrate, a hole transport layer, a perovskite layer, an electron transport layer, and an electrode layer arranged sequentially. Preferably, a modification layer is disposed between the perovskite layer and the electron transport layer, and a hole blocking layer is disposed between the electron transport layer and the electrode layer. The modification layer is EDAI or PEAI, and the hole blocking layer is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline or copper hydroxide. The electron transport layer is fullerene and its derivatives, tin dioxide, or titanium dioxide. The hole transport material can be any material corresponding to any of the following structures or a mixture of any of the materials corresponding to several structures.

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051] .

[0052] The method for fabricating the photovoltaic device in this invention includes the following steps:

[0053] (1) Obtaining the substrate: Select a rigid or flexible substrate, such as a glass substrate doped with fluorine tin oxide (FTO), an indium tin oxide (ITO), a PVC substrate, or a crystalline silicon cell substrate;

[0054] (2) Depositing a hole transport layer on a substrate, preferably by a solution method, the preparation method including: a) dissolving the hole transport material in an organic solvent to obtain a hole transport layer precursor solution, wherein the concentration of the hole transport material in the hole transport layer precursor solution is 0.5~1.5 mg / mL; b) coating the hole transport layer precursor solution onto the substrate; c) annealing to form a film. Preferred hole transport materials are 2,8-bis(6-phenyl-9H-carbazole-3-yl)-4,6-bis(6-(trimethylsilyl)-2-(dimethylamino)-9H-carbazole-3-yl)dibenzo[b,d]thiophene.

[0055] (3) A perovskite layer is formed by depositing perovskite material on the hole transport layer. The deposition method is spin coating, slot coating or vacuum evaporation. The perovskite layer material is a component that can form ABX3, where A is an organic cation or an organic-inorganic cation, B is a lead ion and X is a halogen. The preferred preparation method is the solution method. Taking the perovskite material methylamine lead iodide as an example, the preparation method is described as follows: a. Prepare methylamine lead iodide solution: Dissolve PbI2 and MAI in NN dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). The volume ratio of DMSO to DMF is (1:10) to (1:2). Heat and stir until completely dissolved to obtain methylamine lead iodide solution. b. Spin-coat the prepared methylamine lead iodide solution onto the hole transport layer. c. Anneal under a nitrogen atmosphere and obtain the final product after cooling.

[0056] (4) A modification layer is formed by depositing a modification material on the perovskite layer. The deposition method is coating, such as blade coating or spin coating. The preparation method of the modification layer is as follows: a) Dissolve the modification material in isopropanol and stir magnetically at 600 rpm to form a homogeneous solution of 0.5 mM to 0.5 M. Filter the solution using a filter cartridge to remove larger particles. b) Spin coat the modification material solution onto the perovskite layer at a speed of 1000 to 5000 rpm for 10 to 50 s. Then anneal the solution in a glove box at 60 to 100 °C for 1 to 10 minutes to obtain the modification layer.

[0057] (5) Deposit an electron transport layer on the modification layer. The deposition method can be vacuum evaporation or spin coating. The electron transport layer material is fullerene and its derivatives, tin dioxide or titanium dioxide and other metal oxides.

[0058] (6) An electrode layer is formed by depositing electrode material on the electron transport layer. The deposition method is coating or vacuum evaporation. The material can be gold, silver, copper, etc.

[0059] (7) Deposit a hole blocking layer on the electron transport layer, the material being 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline or copper bath.

[0060] (8) Deposit an antireflection layer on the electrode layer by coating or vacuum evaporation. The material can be magnesium fluoride, silicon nitride, etc.

[0061] The preparation method is simple, low-cost, and produces high film-forming performance.

[0062] The following specific examples will provide further details.

[0063] Example 1

[0064] Hole transport material is:

[0065] .

[0066] The preparation method of this material is as follows:

[0067]

[0068] 1. Preparation of intermediate product: 2,6-dibromo-4,8-bis(4-phenyl-1H-indole-7-yl)benzo[b]thiophene

[0069] a. In a 250 mL flask, add 10.0 g of 1,4-tribromodibenzothiophene, 18.0 g of 5-phenyl-3-carbazoleborate pinacol ester, 7.6 g of sodium carbonate, and 1.4 g of tetra(triphenylphosphine)palladium in sequence. Connect the flask to a magnetic stir bar and connect it to nitrogen gas. Using a syringe, add 75 mL of anhydrous toluene, 40 mL of ethanol, and 50 mL of ultrapure water in sequence to the flask. Stir vigorously to initially disperse the solids.

[0070] b. Introduce nitrogen gas and bubble continuously for 30 minutes to displace the air in the system. Then reduce the nitrogen gas flow rate and heat the reaction system to 90 °C. Maintain this temperature and stir the reaction for 16 hours.

[0071] c. After the reaction is complete, the reaction system is allowed to cool naturally to room temperature. The reaction solution is transferred to a 250 mL separatory funnel, allowed to stand and separate into layers, and the upper organic phase is collected. The aqueous phase is extracted with ethyl acetate, and all organic phases are combined. Anhydrous sodium sulfate is added to the organic phase, the mixture is sealed, and allowed to dry for 2 hours. The sodium sulfate is then removed by filtration. The filtrate is concentrated under reduced pressure on a rotary evaporator to obtain a brownish-yellow crude product. After purification, the crude product yields a pale yellow solid, bis(5-phenylcarbazol-3-yl)-6-bromodibenzothiophene (yield 80%).

[0072] 2. Preparation of intermediate product: 2,6-dibromo-4,8-bis(4-phenyl-1H-indole-7-yl)benzo[b]thiophene

[0073] a. Dissolve 0.50 mL of liquid bromine in 20 mL of anhydrous ethanol to obtain a bromine solution;

[0074] b. In a dry 250 mL round-bottom flask, add 7.5 g of the product from step 3, 120 mL of anhydrous ethanol, and the prepared bromine solution sequentially. Stir until the reaction is complete, then stop stirring and slowly add saturated Na2SO3 solution dropwise until the yellow color of the reaction solution completely disappears. After the reaction solution is allowed to stand and separate into layers, collect the organic phase and combine the organic phases. After drying, filtering, and rotary evaporation, the crude product is obtained. The crude product is then purified by elution to obtain the intermediate product: 2,6-dibromo-4,8-bis(4-phenyl-1H-indol-7-yl)benzo[b]thiophene.

[0075] 3. Preparation of the target compound: 2,8-bis(6-phenyl-9H-carbazole-3-yl)-4,6-bis(6-(trimethylsilyl)-2-(dimethylamino)-9H-carbazole-3-yl)dibenzo[b,d]thiophene

[0076] a. In a dry 250 mL round-bottom flask, add 4.5 g of 2,6-dibromo-4,8-bis(4-phenyl-1H-indol-7-yl)benzo[b]thiophene, 5.5 g of 6-dimethylamino-2-trimethylsilyl-3-carbazoleborate pinacol ester, 3.8 g of sodium carbonate, then add 0.35 g of tetra(triphenylphosphine)palladium, followed by 40 mL of toluene, 20 mL of ethanol and 20 mL of water. Place a magnetic stir bar in the flask, install a single-hole rubber stopper at the mouth of the flask, insert a nitrogen gas delivery tube, and introduce nitrogen gas at a flow rate of 30 mL / min to completely replace the air in the flask.

[0077] b. Reduce the nitrogen flow rate to 10 mL / min, place the flask in an oil bath preheated to 90 °C, start magnetic stirring, and react for 16 hours. After the reaction, cool and allow to stand for separation, collecting the upper organic phase; extract the lower aqueous phase with ethyl acetate and collect the organic phase. The organic phase was dried and rotary evaporated to obtain a dark blue viscous crude product. The dark blue viscous crude product was eluted and purified to obtain the dark blue solid target compound 2,8-bis(6-phenyl-9H-carbazole-3-yl)-4,6-bis(6-(trimethylsilyl)-2-(dimethylamino)-9H-carbazole-3-yl)dibenzo[b,d]thiophene (yield 75%), denoted as Material 1.

[0078] The infrared spectrum of the obtained material 1 is as follows: Figure 5As shown in Figure 6, the region from 1250 to 1000 cm⁻¹ contains characteristic Si-C peaks of trimethylsilyl groups and characteristic peaks of heterocyclic functional groups. The regions near 2960 cm⁻¹ and 2870 cm⁻¹ correspond to characteristic methyl CH peaks of trimethylsilyl groups (-Si(CH₃)₃) and N-methyl groups (-N(CH₃)₂). The region from 3100 to 3000 cm⁻¹ contains characteristic CH peaks of aromatic rings, and the region from 3200 to 3300 cm⁻¹ corresponds to characteristic NH peaks of indole rings. Combined with Figure 6, it can be concluded that the synthesized substance is the desired target compound.

[0079] A pin-type wide-bandgap perovskite (1.67 eV) solar cell was prepared using the obtained target compound. The preparation method includes the following steps:

[0080] S01 Obtain the substrate

[0081] Using ITO glass as the substrate, the ITO glass substrate was first ultrasonically cleaned in deionized water for 30 minutes, then ultrasonically cleaned in acetone for 30 minutes, and finally ultrasonically cleaned in isopropanol (IPA) for 30 minutes. After that, it was dried with a nitrogen gun and placed in a UV ozone processor for 30 minutes for later use.

[0082] S02 is used to prepare the hole transport layer.

[0083] (1) Mix 1 mg of Material 1: 2,8-bis(6-phenyl-9H-carbazole-3-yl)-4,6-bis(6-(trimethylsilyl)-2-(dimethylamino)-9H-carbazole-3-yl)dibenzo[b,d]thiophene with 1 mL of methanol and DMSO solvent (methanol:DMSO=95:5) to obtain a 1 mg / mL solution of Material 1. Filter the solution with a 0.45 μm filter to remove large particles. The filtered solution is ready for use.

[0084] (2) Spin-coat the filtered solution onto ITO glass at a spin rate of 4000 rpm for 40 s;

[0085] (3) Anneal at 100 °C for 10 min to obtain a hole transport layer with a thickness of about 3 nm.

[0086] S03 preparation of perovskite layer

[0087] (1) Preparation of perovskite solution

[0088] a. Dissolve 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 in 0.80 mL of DMF (NN dimethylformamide) and 0.2 mL of DMSO (dimethyl sulfoxide). Stir at room temperature for at least 4 hours until completely dissolved. Filter the solution using a 0.45 μm organic filter cartridge to obtain solution one: 1.7 MFA 0.8 MA 0.15 Cs 0.05 Pb(I) 0.75 Br 0.25 )3 solution;

[0089] b. Add MACl additive to solution one to form solution two, where the mass fraction of MACl in solution two is 20%;

[0090] c. Heat the solution to 20-70°C and stir for 70 minutes until completely dissolved;

[0091] d. Filter the solution using a 0.22 μm filter cartridge to remove large particles and obtain a perovskite layer solution.

[0092] (2) Spin-coat the perovskite solution onto the hole transport layer at a spin-coating rate of 4000 rpm. At the 10th s of spin-coating, add 0.2 mL of the anti-solvent chlorobenzene onto the film. After the addition is completed within 2 s, continue spin-coating for a total of 40 s.

[0093] (3) After spin coating, anneal in air at 100 °C for 20 min with humidity controlled at 20~30% to obtain a perovskite layer with a thickness of about 700 nm.

[0094] S04 Preparation of Modification Layer

[0095] (1) Preparation of the modified layer: Dissolve 0.5 mg of PEAI (phenylethyl iodide) in 1 mL of isopropanol, shake and stir to form an isopropanol solution of 0.5 mg / mL PEAI, and filter the solution with a 0.45 μm filter to remove larger particles and obtain the PEAI solution.

[0096] (2) Spin-coat the PEAI solution onto the perovskite layer at a speed of 2000 rpm for 30 s, and then anneal it in a glove box at 100 ℃ for 30 s to form a PEAI modified layer with a thickness of about 3 nm.

[0097] S05 is used to prepare the electron transport layer.

[0098] Vacuum evaporation equipment is used to evaporate C using a thermal evaporation method. 60The material forms a 20 nm electron transport layer on the perovskite layer, with a deposition vacuum of 7*10⁻⁶. -4 Below Pa.

[0099] Preparation of S06 Hole Blocking Layer

[0100] 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 an 8 nm hole-blocking layer on the electron transport layer. The evaporation vacuum degree was 7*10 -4 Below Pa.

[0101] Preparation of S07 electrode

[0102] Using vacuum evaporation equipment, 150nm copper (Cu) was deposited as an electrode on the surface of BCP via thermal evaporation, with a evaporation vacuum degree of 7*10. -4 Below Pa.

[0103] Example 2

[0104] Hole transport material is:

[0105]

[0106] The synthesis method is as follows:

[0107]

[0108] 1. Preparation of pale yellow solid 4-(4-phenyl-1H-indol-7-yl)-8-(4-phenyl-2,3-dihydro-1H-indol-7-yl)benzo[b]thiophene

[0109] In a 250 mL dry round-bottom flask, add 10.0 g of 1,4-tribromodibenzothiophene, 18.0 g of 5-phenyl-3-carbazoleborate pinacol ester, 7.6 g of sodium carbonate, and 1.4 g of tetrakis(triphenylphosphine)palladium in sequence. Connect a magnetic stir bar to the flask, install a rubber stopper at the mouth of the flask, insert a nitrogen gas delivery tube, and add 75 mL of anhydrous toluene, 40 mL of ethanol, and 50 mL of ultrapure water in sequence through the side opening of the nitrogen gas delivery tube using a dry syringe. Stir vigorously to initially disperse the solids.

[0110] b. Purge the air in the system with nitrogen; then reduce the nitrogen flow rate and heat the oil bath to 90 °C, maintaining this temperature while stirring the reaction for 16 hours.

[0111] c. After the reaction is complete, remove the flask from the oil bath and allow it to cool naturally to room temperature. Transfer the reaction solution to a 250 mL separatory funnel, allow it to stand and separate into layers, collect the organic phases, and combine the organic phases. Then, dry the organic phases with anhydrous sodium sulfate, filter, and rotary evaporate to obtain a brownish-yellow crude product. After elution and purification, the brownish-yellow crude product yields a pale yellow solid 4-(4-phenyl-1H-indol-7-yl)-8-(4-phenyl-2,3-dihydro-1H-indol-7-yl)benzo[b]thiophene (yield 80%).

[0112] 2. Preparation of 2,6-dibromo-4,8-bis[(4-phenyl-1H-indol-7-yl)benzo[b]thiophene]

[0113] a. Add 5.0 g of the product obtained in step 1: 4-(4-phenyl-1H-indol-7-yl)-8-(4-phenyl-2,3-dihydro-1H-indol-7-yl)benzo[b]thiophene and 120 mL of anhydrous ethanol to a 250 mL two-necked flask, and stir to dissolve at room temperature.

[0114] b. Prepare bromine solution: Dissolve 0.32 mL of liquid bromine in 15 mL of anhydrous ethanol to obtain bromine solution;

[0115] The bromine solution was added to the aforementioned round-bottom flask and the mixture was stirred to react.

[0116] After reaction d is complete, slowly add saturated Na2SO3 solution dropwise to the flask until the yellow color of the reaction solution completely disappears; after the reaction solution is allowed to stand and separate into layers, collect the organic phase; extract the aqueous phase with ethyl acetate and combine all organic phases;

[0117] Anhydrous sodium sulfate was added to the organic phase, and after drying, filtration and rotary evaporation, crude product was obtained. The crude product was purified by elution to obtain a pale yellow solid 2,6-dibromo-4,8-bis[(4-phenyl-1H-indol-7-yl)benzo[b]thiophene].

[0118] 3. Preparation of the target compound

[0119] a) 2.3 g of 2,6-dibromo-4,8-bis[(4-phenyl-1H-indol-7-yl)benzo[b]thiophene], 1.5 g of 6-trifluoromethylcarbazole-3-boronic acid pinacol ester, 0.2 g of Pd(PPh3)4, and 0.9 g of Na2CO3 were added to a 250 mL two-necked flask. Under nitrogen protection, 30 mL of anhydrous toluene, 8 mL of anhydrous ethanol, and 8 mL of deionized water were added to the flask sequentially through a syringe. The mixture was stirred to ensure thorough dispersion of the solids. The reaction system was heated to 110 °C, stirred, and refluxed for 16 h.

[0120] After reaction b is completed, the reaction system is cooled to room temperature, 30 mL of deionized water is added, the organic phase is separated, anhydrous sodium sulfate is added to the organic phase for drying, and then filtered and rotary evaporated to obtain a brownish-yellow solid crude product.

[0121] The crude product was eluted to obtain the target compound: 2,8-bis(6-phenyl-9H-carbazole-3-yl)-4,6-bis(6-(trifluoromethyl)-9H-carbazole-3-yl)dibenzo[b,d]thiophene (0.74 g, yield 60%), denoted as Material 2.

[0122] The infrared spectrum of material 2 is as follows Figure 5 As shown in Figure 6, the region around 1000–1100 cm⁻¹ contains the CN characteristic peak of the indole ring and the CS characteristic peak of the thiophene ring. The region around 1300–1100 cm⁻¹ corresponds to the CF characteristic peak of trifluoromethyl (-CF3). The region around 3100–3000 cm⁻¹ belongs to the CH characteristic peak of the aromatic ring, and the region around 3200–3300 cm⁻¹ corresponds to the NH characteristic peak of the indole ring. Combined with Figure 6, it can be seen that the synthesized substance is the desired target compound.

[0123] The perovskite photovoltaic device was prepared using this hole transport material. The differences between the preparation method and Example 1 are only (1) the hole transport material and solution are different; (2) the perovskite material is different; and (3) the preparation method of the perovskite solution is different. The hole transport material in this example is material 2: 2,8-bis(6-phenyl-9H-carbazole-3-yl)-4,6-bis(6-(trifluoromethyl)-9H-carbazole-3-yl)dibenzo[b,d]thiophene. 1.0 mg of the hole transport material was dissolved in 2 mL of methanol and DMSO solvent (methanol:DMSO=95:5) to obtain a 0.5 mg / mL solution of material 2. The perovskite material is FA. 0.78 Cs 0.22 Pb(I 0.82 Br 0.18 3. The preparation process of the perovskite solution is as follows: Weigh 471.2 mg PbI2, 80.1 mg CsI, 187.8 mg FAI and 138.7 mg PbBr2 and dissolve them in 1 mL of a mixed solvent of DMF and DMSO, wherein the volume ratio of DMF to DMSO is 4:1. Stir the solution overnight at room temperature in a glove box until completely dissolved, and filter it using a 0.22 μm organic filter to obtain the perovskite solution.

[0124] Example 3

[0125] Hole transport material is:

[0126] .

[0127] The synthesis method is as follows:

[0128]

[0129] 1. Preparation of intermediate product: 2-(1H-benzimidazol-2-yl)-9H-carbazole

[0130] Add 6.09 g of 2-bromo-1H-benzo[d]imidazole and 8.15 g of 3-boronico-9H-carbazole to a 100 mL three-necked flask in sequence. After stirring and mixing evenly, add 1.38 g of potassium carbonate powder, followed by 20 mL of anhydrous 1,4-dioxane and 0.19 g of Pd(dppf)Cl2. Stir to disperse the solution, and slowly add 5 mL of ultrapure water. At this point, the solution is a light brown suspension.

[0131] The reaction system is heated in an oil bath at 100 °C. The reaction is complete when the starting material 2-bromo-1H-benzo[d]imidazole disappears.

[0132] After the reaction is complete, cool to room temperature, add 20 mL of saturated saline solution to the flask, and transfer the reaction solution to a separatory funnel to obtain the organic phase.

[0133] The organic phase was dried with anhydrous sodium sulfate, and then filtered and rotary evaporated to obtain a brownish-black oily crude product.

[0134] The crude product was eluted to give a light yellow solid. The solid was dissolved in hot ethyl acetate and slowly cooled to 0 °C, resulting in the precipitation of light gray needle-like crystals. The crystals were filtered and dried under vacuum to give the intermediate product: 2-(1H-benzimidazol-2-yl)-9H-carbazole (yield 70%).

[0135] 2. Preparation of intermediate product: 2-(1H-benzimidazol-2-yl)-9H-carbazoleboronic acid pinacol ester

[0136] In a 250 mL round-bottom flask, add 4.8 g of 2-(1H-benzimidazol-2-yl)-9H-carbazole, 3.5 g of 4,4,5,5-tetramethyl-1,3,2-dioxaborane-2-alkyl (HBpin), 5.2 mg of 4,4'-di-tert-butyl-2,2'-bipyridine ligand, 25 mL of 1,4-dioxane, and 100 mL of ultrapure water, and stir to initially disperse the solid.

[0137] b. Nitrogen gas is introduced to replace the air in the system. The system is heated to 85 °C in an oil bath and stirred at this temperature until the reaction is complete.

[0138] After reaction c is completed, the flask is removed from the oil bath, and the intermediate product is obtained by collecting the organic phase, drying, filtering, and rotary evaporation: 2-(1H-benzimidazol-2-yl)-9H-carbazoleboronic acid pinacol ester.

[0139] 3. Preparation of intermediate product: 2,7-bis(2-benzothiazol-2-yl)-9,9'-bicarbazole-dibenzothiophene

[0140] In a 250 mL dry round-bottom flask, 2.5 g of 1,4-dibromodibenzothiophene, 4.5 g of 2-(1H-benzimidazol-2-yl)-9H-carbazoleborate pinacol ester, 7.6 g of sodium carbonate, and 0.7 g of tetra(triphenylphosphine)palladium were added sequentially. Then, 50 mL of anhydrous toluene, 25 mL of ethanol, and 25 mL of ultrapure water were added sequentially using a dry syringe, and the mixture was stirred vigorously to initially disperse the solids.

[0141] b. Introduce nitrogen gas at a flow rate of 50 mL / min and bubble continuously for 30 minutes to displace the air in the system; then reduce the nitrogen flow rate to 10 mL / min, heat the oil bath to 90 °C, and maintain this temperature while stirring the reaction for 16 hours.

[0142] After reaction c is complete, remove the flask from the oil bath and allow it to cool naturally to room temperature. After the reaction solution is allowed to stand and separate into layers, collect the organic phase and extract the aqueous phase with ethyl acetate. Combine all organic phases.

[0143] The organic phase obtained was dried with anhydrous sodium sulfate, and then filtered to remove the sodium sulfate. The filtrate was then rotary evaporated to obtain a brownish-yellow crude product.

[0144] The crude product was eluted to give the intermediate product: 2,7-bis(2-benzothiazol-2-yl)-9,9'-bicarbazole-dibenzothiophene (yield 70%).

[0145] 4. Preparation of 2,6-dibromo-2,7-bis(2-benzothiazol-2-yl)-9,9'-bicarbazole-dibenzothiophene

[0146] Add 4.8 g of the product obtained in step 3, 2,7-bis(2-benzothiazol-2-yl)-9,9'-bicarbazole-dibenzothiophene, and 120 mL of anhydrous ethanol to a 250 mL two-necked flask, and stir to dissolve at room temperature.

[0147] b. Prepare bromine solution: Dissolve 0.32 mL of liquid bromine in 15 mL of anhydrous ethanol to obtain bromine solution;

[0148] The bromine solution was added to the aforementioned round-bottom flask and the mixture was stirred to react.

[0149] After reaction d is complete, slowly add saturated Na2SO3 solution dropwise to the flask until the yellow color of the reaction solution completely disappears; after the reaction solution is allowed to stand and separate into layers, collect the organic phase; extract the aqueous phase with ethyl acetate and combine all organic phases;

[0150] Anhydrous sodium sulfate was added to the organic phase, and after drying, filtration and rotary evaporation, a crude product was obtained. The crude product was then purified by elution to obtain a pale yellow solid, 2,6-dibromo-2,7-bis(2-benzothiazol-2-yl)-9,9'-bicarbazole-dibenzothiophene.

[0151] 5. Preparation of the target compound: 2,8-bis(6-(2-mercaptobenzo[d]imidazol-2-yl)-9H-carbazole-3-yl)-4,6-bis(6-methyl-9H-carbazole-3-yl)dibenzo[b,d]thiophene

[0152] In a dry 250 mL round-bottom flask, add 2.5 g of 2,6-dibromo-2,7-bis(2-benzothiazol-2-yl)-9,9'-bicarbazole-dibenzothiophene, 2.8 g of 3-methyl-9H-carbazoleborate pinacol ester, and 3.8 g of sodium carbonate, followed by 0.35 g of tetra(triphenylphosphine)palladium. Then add 40 mL of toluene, 20 mL of ethanol, and 20 mL of water. Place a magnetic stir bar in the flask, install a single-hole rubber stopper at the mouth of the flask, and insert a nitrogen gas delivery tube.

[0153] b. Introduce nitrogen gas at a flow rate of 30 mL / min and bubble continuously for 30 minutes to completely displace the air in the flask; then reduce the nitrogen flow rate to 10 mL / min to maintain a slight positive pressure in the system and prevent backflow of air. Place the flask in an oil bath preheated to 90 °C, start magnetic stirring, and react for 16 hours.

[0154] After reaction c is complete, remove the flask and allow it to cool naturally to room temperature. Transfer the reaction solution to a 250 mL separatory funnel, collect the organic phase, add anhydrous sodium sulfate to the organic phase to dry it, and then filter to remove the anhydrous sodium sulfate. Transfer the filtrate to a rotary evaporator and concentrate it under reduced pressure at 40 °C and 0.095 MPa until no solvent drips out, yielding a dark blue viscous crude product.

[0155] After elution, the crude product yielded a dark blue solid target compound: 2,8-bis(6-(2-mercaptobenzo[d]imidazol-2-yl)-9H-carbazole-3-yl)-4,6-bis(6-methyl-9H-carbazole-3-yl)dibenzo[b,d]thiophene (yield 75%), denoted as Material 3.

[0156] The infrared spectrum of the obtained material 3 is as follows: Figure 5As shown in Figure 6, the 1250–1000 cm⁻¹ region contains characteristic peaks of heterocyclic functional groups, the C=N characteristic peak and the CS characteristic peak of benzothiazole; the 2960 cm⁻¹ and 2870 cm⁻¹ regions correspond to the CH characteristic peaks of methyl (-CH₃); the 3100–3000 cm⁻¹ region belongs to the CH characteristic peaks of aromatic rings; and the 3200–3300 cm⁻¹ region corresponds to the NH characteristic peaks of indole rings. Based on Figure 6, it can be seen that the synthesized substance is the desired target compound.

[0157] The perovskite battery was prepared using the obtained material 3. The only differences between the preparation method and that in Example 1 are: (1) the hole transport material and the hole transport material solution are different, and (2) the perovskite precursor material and the preparation process are different. The hole transport material in this example is material 3: 2,8-bis(6-(2-mercaptobenzo[d]imidazol-2-yl)-9H-carbazole-3-yl)-4,6-bis(6-methyl-9H-carbazole-3-yl)dibenzo[b,d]thiophene. 1.5 mg of material 3 was dissolved in 1 mL of methanol and DMSO solvent (methanol:DMSO=95:5) to obtain a 1.5 mg / mL solution of material 2.

[0158] The perovskite layer preparation process is as follows:

[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 70 °C for 12 h to obtain solution A;

[0160] (2) 235.5 mg FAI, 41.3 mg MAI and 21.9 mg CsI were added to 1 mL of IPA solvent and stirred at room temperature for 4 h to obtain solution B;

[0161] (3) Take 80 μL of solution A and add it to the hole transport layer for spin coating. The spin coating process is 2000 rpm for 40 s. 20 s before the end of spin coating, add 100 μL of CB as an anti-solvent. Then anneal at 70 ℃ for 10 min.

[0162] (4) Take 100 μL of solution B and spin coat it. The spin coating process is 5000 rpm for 30 s. After spin coating, the perovskite film is pre-annealed on a 50 ℃ hot plate for 1 min, and then annealed on a 100 ℃ annealing plate for 20 min to obtain a complete perovskite layer. Other steps are the same as in Example 1.

[0163] Example 4

[0164] The fabrication method of the perovskite photovoltaic device in this embodiment includes the following steps:

[0165] S01 Obtain the substrate

[0166] 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 15 minutes before use.

[0167] S02 is used to prepare the hole transport layer.

[0168] (1) Dissolve 1 mg of material 3: 2,8-bis(6-(2-mercaptobenzo[d]imidazol-2-yl)-9H-carbazole-3-yl)-4,6-bis(6-methyl-9H-carbazole-3-yl)dibenzo[b,d]thiophene in 1 mL of a mixed solvent of methanol and DMSO (methanol:DMSO=95:5) to obtain a 1 mg / mL solution of the material. Filter the solution using a 0.45 μm filter to remove large particles and obtain a hole transport material solution.

[0169] (2) Spin-coat the filtered solution onto ITO glass at a spin rate of 4000 rpm for 40 s;

[0170] (3) Anneal at 100 °C for 10 min to obtain a hole transport layer with a thickness of about 3 nm.

[0171] S03 for preparing perovskite films

[0172] (1) Preparation of perovskite layer solution

[0173] a. 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 stirred at room temperature for at least 4 hours until completely dissolved, and then filtered through a 0.45 μm organic filter to obtain 1.7 MFA. 0.8 MA 0.15 Cs 0.05 Pb(I) 0.75 Br 0.25 )3 solution.

[0174] b. Add MACl additive to solution one to form solution two, where the mass fraction of MACl in solution two is 20%.

[0175] c. Heat the solution to 20-70°C and stir for 70 minutes until completely dissolved;

[0176] d. Filter the solution using a 0.22 μm filter cartridge to remove large particles from the solution and obtain a perovskite membrane solution.

[0177] (2) Spin-coat the perovskite film solution onto the hole transport layer at a spin coating rate of 4000 rpm. At the 10th s of spin coating, add 0.2 mL of the anti-solvent chlorobenzene to the film. After the addition is completed within 2 s, continue spin coating for a total of 40 s.

[0178] (3) After spin coating, anneal in air at 100 °C for 20 min with humidity controlled at 20~30% to obtain a perovskite film with a thickness of about 700 nm.

[0179] S04 Preparation of Modification Layer

[0180] (1) Preparation of the modified material solution: Dissolve 0.5 mg of PEAI (phenylethyl iodide) in 1 mL of isopropanol, shake and stir to form an isopropanol solution of 0.5 mg / mL PEAI, and filter the solution with a 0.45 μm filter to remove larger particles and obtain the PEAI solution.

[0181] (2) Spin-coat the PEAI solution onto the perovskite layer at a speed of 2000 rpm for 30 s, and then anneal it in a glove box at 100 ℃ for 30 s to form a PEAI modified layer with a thickness of about 3 nm.

[0182] S05 is used to prepare the electron transport layer.

[0183] 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 perovskite film, with a deposition vacuum of 7*10. -4 Below Pa.

[0184] S06 Preparation of Hole Blocking Layer

[0185] 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 an 8 nm hole-blocking layer on the electron transport layer. The evaporation vacuum degree was 7*10 -4 Below Pa.

[0186] S07 Electrode Preparation

[0187] Using a vacuum evaporation device, 150 nm copper (Cu) was deposited as an electrode on the surface of BCP via thermal evaporation, with a evaporation vacuum degree of 7*10. -4 Below Pa.

[0188] Comparative Example 1

[0189] The only difference from Example 1 is the use of a different hole transport material. In this comparative example, the hole transport material is Me-4PACz ((4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid, that is, the hole transport material in step S02 of Example 1 is changed to Me-4PACz ((4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid). The other steps are the same as in Example 1.

[0190] Comparative Example 2

[0191] The difference from Example 4 lies only in the use of different hole transport materials and modification materials. The hole transport layer is 2,3,5,6-tetra(9H-carbazole-3-yl)thieno[3,2-b:4,5-b']dibenzothiophene, meaning the hole transport material in step S02 of Example 1 is replaced with a solution of 2,3,5,6-tetra(9H-carbazole-3-yl)thieno[3,2-b:4,5-b']dibenzothiophene. The modification material is 1,3-diaminopropane dihydroiodate (PDAI2). 1 mg of PDAI2 is dissolved in 1 ml of isopropanol solution to obtain the modification material solution. Other steps are the same as in Example 1.

[0192] The photoelectric conversion efficiency of the perovskite solar cells obtained in Example 1 and 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. The test results are as follows. Figure 1 As shown in Table 1, compared with Comparative Example 1, the open-circuit voltage and conversion efficiency of perovskite solar cells in Examples 1, 2, and 3 are significantly improved. Among them, the open-circuit voltage and conversion efficiency of the perovskite cell based on Example 3 are 1.25 V and 23.52%, respectively, indicating that the material in this invention can effectively improve the performance of perovskite solar cells.

[0193] Table 1 Performance parameters of perovskite solar cells obtained in Examples 1, 2, 3, and Comparative Example 1

[0194] Voc (V) Jsc(mA / cm 2 )]]> FF (%) PCE (%) Comparative Example 1 1.17 21.85 80.23 20.51 Example 1 1.23 22.29 84.30 23.15 Example 2 1.23 22.06 83.90 22.76 Example 3 1.25 22.24 84.60 23.52

[0195] The photoelectric conversion efficiency of the perovskite / silicon tandem solar cells in Example 4 and Comparative Example 2 was tested using 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 power of sunlight. The results are as follows: Figure 2As shown in Table 2, compared with Comparative Example 2, the conversion efficiency of the perovskite / silicon tandem device prepared in Example 4 is significantly improved, indicating that the hole transport material in this invention can improve battery performance.

[0196] Table 2 Performance parameters of the perovskite solar cells obtained in Comparative Example 2 and Example 4

[0197] Voc (V) Jsc(mA / cm 2 )]]> FF (%) PCE (%) Comparative Example 2 1.83 18.75 77.86 26.72 Example 4 1.91 19.48 80.23 29.85

[0198] By observing the microstructure of the perovskite layer in the perovskite photovoltaic devices obtained in Example 1 and Comparative Example 1, it can be seen that in Comparative Example 1, there is less precipitation on the perovskite surface, the grain size is large, and the precipitation of lead iodide on the perovskite surface is significantly reduced. This proves that the hole transport material in this invention helps the perovskite material to crystallize better, reduces perovskite surface defects, and is conducive to better charge transport.

[0199] 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 perovskite photovoltaic device, characterized in that: The system comprises a hole transport layer, a perovskite layer, and an electron transport layer. The perovskite layer generates free electrons and holes under photoexcitation. The free electrons enter the electron transport layer, and the holes enter the hole transport layer. The hole transport layer contains an organic material M, the structural formula of which is: In the formula: R1 and R4 are each independently selected from one or more combinations of hydrogen atom, mercapto, silyl, tert-butyl, adamantyl, short-chain alkyl, and short-chain alkyl derivatives; R2 and R3 are each independently selected from one or more combinations of hydrogen atom, short-chain alkyl, short-chain alkyl derivatives, amino, amino derivatives, halogen, and aryl; R5 and R6 are each independently selected from aryl or its derivatives, wherein the short-chain alkyl is -C. n H 2n+1 , 1≤n≤3.

2. The perovskite photovoltaic device according to claim 1, characterized in that: The perovskite layer contains a perovskite material, wherein the perovskite material is ABX3, and A is FA. + MA + Cs + One or more combinations of B, where B is Pb + C is I - ,Br - Cl - One or more combinations thereof.

3. The perovskite photovoltaic device according to claim 2, characterized in that: The perovskite material ABX3 contains at least FA in A. + or MA + B is Pb + C contains at least I - or Br - .

4. The perovskite photovoltaic device according to claim 1, characterized in that: The hole transport layer is deposited on the substrate, and a metal oxide thin film layer is disposed on the side of the substrate connected to the hole transport layer; the perovskite layer is deposited on the hole transport layer, and the hole transport layer is in direct contact with the perovskite layer.

5. The perovskite photovoltaic device according to claim 1, characterized in that: In the structural formula of the organic material M, one of R1 or R4 is silyl or / and tert-butyl or / and adamantyl, and the other is methyl, ethyl, methyl derivative or ethyl derivative, and at least one of R2 and R3 is amino or amino derivative.

6. The perovskite photovoltaic device according to claim 1, characterized in that: The structural formula of organic material M is: 。 7. The perovskite photovoltaic device according to claim 1, characterized in that: A modification layer is disposed between the perovskite layer and the electron transport layer, and a hole blocking layer is disposed on the side of the electron transport layer opposite to the perovskite layer. The modification layer is PEAI, and the hole blocking layer is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline or copper bath.

8. A method for fabricating the perovskite photovoltaic device according to claim 1, characterized in that: Includes the following steps: S01 Obtain the substrate; SO2 is used to prepare the hole transport layer; S03 is used to prepare a perovskite layer, wherein the perovskite layer is a lead-based perovskite material; SiO4 is used to prepare an electron transport layer; The hole transport layer is prepared by a solution method, which includes: a) dissolving the hole transport material in an organic solvent to obtain a hole transport material precursor solution; b) coating the hole transport material precursor solution onto a substrate; and c) annealing to form a film.

9. The preparation method according to claim 8, characterized in that: The concentration of hole transport material in the precursor solution is 0.5~1.5 mg / mL.

10. A hole transport material, characterized in that: The structural formula is ； In the formula: R1 and R4 are each independently selected from one or more combinations of hydrogen atom, thio group, alkyl group, silyl group, tert-butyl group, adamantyl group or their derivatives; R2 and R3 are each independently selected from one or more combinations of hydrogen atom, amino group or amino derivative, halogen, alkyl group or aryl group; R5 and R6 are each independently selected from aryl group or their derivatives.

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