A dibenzofuranyl carbazole derivative, and a preparation method and application thereof

Abstract

The application belongs to the technical field of perovskite solar cells, and provides a dibenzofuranyl carbazole derivative, a preparation method and application thereof. The dibenzofuranyl carbazole is used as a functional group, the molecular ordered accumulation is optimized, and the hole mobility is significantly improved. The alkyl carbon chain is used as a connecting group, and the terminal phosphoric acid group is used as an anchoring group. The perovskite interface defects can be effectively passivated, the energy loss at the interface can be reduced, the single-molecule self-assembly can be realized, and the battery performance can be improved. As a self-assembled monolayer hole transport material, the perovskite solar cell has high photoelectric conversion efficiency, long service life and stability.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell technology, and particularly relates to a dibenzofuranylcarbazole derivative, its preparation method and application. Background Technology

[0002] Perovskite solar cells (PSCs) are a new type of photovoltaic cell, belonging to the third generation of solar cells. In just over a decade, their certified efficiency has reached 26.7% (National Renewable Energy Laboratory, NREL, 2024), demonstrating tremendous application potential.

[0003] Perovskite solar cells typically consist of a transparent electrode, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and a metal electrode. Among these, the transport layer plays a crucial role. It is responsible for selectively extracting and transporting electrons or holes after photogenerated carriers are generated in the perovskite light-absorbing layer, while blocking the other type of carrier to prevent recombination, thereby ensuring efficient current output.

[0004] Currently, the most common hole transport material in perovskite solar cells is Spiro-OMeTAD, which contains spirofluorene units and has a high glass transition temperature, thus ensuring the uniformity and stability of the thin film. To obtain good conductivity and transport performance, hygroscopic dopants such as lithium salts and cobalt salts must be added. These additives absorb moisture from the air, severely exacerbating the decomposition of the perovskite layer and seriously affecting the long-term stability of the device. For example, patent CN105153085A discloses a dibenzofuran derivative based on a fluorene core, introducing a diarylamine or carbazole group with excellent hole transport performance at the 2,8-position. It adds three additives to the hole transport layer in the perovskite cell: lithium bis(trifluoromethanesulfonyl)imide, 4-tert-butylpyridine, and tris(2-(1H-pyrazol-1-yl)pyridine)cobalt, but the device's fill factor is only 63-65%, the photoelectric conversion efficiency is only a few percent, and the device stability is poor.

[0005] Self-assembled monolayer (SAM) transport materials can overcome the defects caused by dopants. These molecules, with specific anchoring groups at one end and functional groups at the other, are spin-coated onto a substrate. The anchoring groups form strong chemical bonds with the substrate surface, resulting in an ordered, dense, and completely covered ultrathin film. This significantly reduces energy loss at the interface, substantially increases the open-circuit voltage of the circuit, avoids the use of dopants, and forms a stable and dense chemically bonded layer, thus significantly improving the stability and electrochemical performance of the device.

[0006] Therefore, developing a novel SAM material that is simple in structure, low in cost, and has excellent performance is an urgent problem to be solved in this field. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a dibenzofuranylcarbazole derivative, its preparation method, and its applications. By designing the structure of the compound and using it as a self-assembled monolayer hole transport material, this invention features high hole transport efficiency, strong interface passivation, and high thermal stability, enabling perovskite solar cells to have high photoelectric conversion efficiency, long service life, and stability.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a dibenzofuranylcarbazole derivative having the structure shown in Formula I:

[0010] ;

[0011] R1 is selected from substituted or unsubstituted C6-C12 aryl groups and unsubstituted C6-C12 heteroaryl groups.

[0012] The dibenzofuranylcarbazole derivative in this invention uses dibenzofuranylcarbazole as a functional group, which optimizes the ordered molecular stacking and significantly improves hole mobility. The alkyl carbon chain serves as a linking group, and the terminal phosphate group serves as an anchoring group, which can effectively passivate perovskite interface defects, reduce energy loss at the interface, and enable single-molecule self-assembly, thereby improving battery performance. As a self-assembled monolayer hole transport material, it enables perovskite solar cells to have high photoelectric conversion efficiency, long service life, and stability.

[0013] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0014] Preferably, the substituent is selected from any one of fluorine, chlorine or tert-butyl.

[0015] Preferably, the C6-C12 (e.g., C6, C7, C8, C9, C10, C11 or C12) aryl group is selected from phenyl or naphthyl.

[0016] Preferably, the C6-C12 (e.g., C6, C7, C8, C9, C10, C11 or C12) heteroaryl group is selected from dibenzofuranyl.

[0017] Preferably, R1 is selected from any one of the following structures:

[0018] , , , , ;

[0019] Dashed lines indicate connection points.

[0020] Preferably, the dibenzofuranylcarbazole derivative is selected from any one of the following compounds A1-A5:

[0021] ;

[0022] .

[0023] In a second aspect, the present invention provides a method for preparing the dibenzofuranylcarbazole derivative as described in the first aspect, the method comprising the following steps:

[0024] (1) The starting material is reacted with diethyl-4-bromobutylphosphonic acid to obtain intermediate I;

[0025] ;

[0026] (2) Intermediate I undergoes a hydrolysis reaction to obtain the dibenzofuranylcarbazole derivative;

[0027] ;

[0028] R1 has the same choice as described above.

[0029] Preferably, in step (1), the molar ratio of the starting material to diethyl-4-bromobutylphosphonic acid is 1:(1-1.2), for example, it can be 1:1.05, 1:1.1, 1:1.15 or 1:1.2, etc.

[0030] Preferably, in step (1), the reaction is carried out in a solvent.

[0031] Preferably, in step (1), the solvent includes N,N-dimethylacetamide.

[0032] Preferably, in step (1), the reaction is carried out in the presence of a catalyst.

[0033] Preferably, in step (1), the catalyst comprises cuprous iodide.

[0034] Preferably, in step (1), the reaction is carried out in the presence of an alkaline substance.

[0035] Preferably, in step (1), the alkaline substance includes potassium carbonate and / or sodium carbonate.

[0036] Preferably, in step (1), the reaction temperature is 160-180℃, for example, it can be 160℃, 165℃, 170℃, 175℃ or 180℃.

[0037] Preferably, in step (1), the reaction time is 20-24 hours, for example, 20 hours, 21 hours, 22 hours, 23 hours or 24 hours.

[0038] Preferably, in step (2), the hydrolysis reaction is carried out in the presence of trimethylbromosilane.

[0039] Preferably, the molar ratio of trimethylbromosilane to intermediate I is (2-4):1, for example, it can be 2:1, 2.5:1, 3:1, 3.5:1 or 4:1, etc.

[0040] Preferably, in step (2), the hydrolysis reaction is carried out in an organic solvent selected from dichloromethane and / or trichloromethane.

[0041] Preferably, in step (2), the hydrolysis reaction is carried out at room temperature, and the hydrolysis reaction time is 12-18h, for example, 12h, 13h, 14h, 15h, 16h, 17h or 18h.

[0042] Thirdly, the present invention provides a perovskite solar cell, the perovskite solar cell comprising a self-assembled monolayer, the self-assembled monolayer comprising the hole transport material based on the dibenzofuranylcarbazole derivative described in the first aspect.

[0043] Preferably, the perovskite solar cell is an inverted perovskite solar cell.

[0044] Preferably, the perovskite solar cell includes a cathode layer, an electron transport layer, a passivation layer, a perovskite light-absorbing layer, a self-assembled monolayer, and an anode layer.

[0045] Preferably, the perovskite solar cell further includes a hole transport layer located between the self-assembled monolayer and the anode layer.

[0046] Preferably, the self-assembled monolayer is obtained by coating a solution of a self-assembled monolayer hole transport material based on a dibenzofuranylcarbazole derivative as described in the first aspect onto the surface of a hole transport layer and then performing thermal annealing.

[0047] Preferably, the temperature of the heat annealing is 80-120℃ (e.g., 80℃, 90℃, 100℃, 110℃ or 120℃, etc.), and the heat annealing time is 5-20min (e.g., 5min, 10min, 15min or 20min, etc.).

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] This invention uses dibenzofuranylcarbazole as a functional group to optimize the ordered molecular stacking and significantly improve hole mobility. The alkyl carbon chain serves as a linking group, and the terminal phosphate group serves as an anchoring group, which can effectively passivate perovskite interface defects, reduce energy loss at the interface, and enable single-molecule self-assembly, thereby improving battery performance. As a self-assembled monolayer hole transport material, it enables perovskite solar cells to have high photoelectric conversion efficiency, long service life, and stability. Attached Figure Description

[0050] Figure 1 The 1H NMR spectrum of intermediate I prepared in Example 1;

[0051] Figure 2 The 1H NMR spectrum of compound A1 prepared in Example 1;

[0052] Figure 3 JV curves of perovskite solar cells fabricated using compound A1 as a hole transport material;

[0053] Figure 4 This is a schematic diagram of the perovskite solar cell structure in this invention;

[0054] Figure 5 The adsorption model and density of states of compound A1;

[0055] Figure 6 The adsorption model and density of states of compound A2;

[0056] Figure 7 The adsorption model and density of states of compound A3;

[0057] Figure 8 The adsorption model and density of states of compound A4;

[0058] Figure 9 The adsorption model and density of states of compound A5;

[0059] Figure 10 The adsorption model and density of states for Comparative Example 1;

[0060] Figure 11 The adsorption model and density of states for Comparative Example 2;

[0061] Figure 12 The adsorption model and density of states for Comparative Example 3;

[0062] Figure 13 The adsorption model and density of states for Comparative Example 4;

[0063] Figure 14 The adsorption model and density of states for Comparative Example 5;

[0064] Figure 15 The adsorption model and density of states for Comparative Example 6;

[0065] Figure 16 The adsorption model and density of states for Comparative Example 7;

[0066] Figure 17 The adsorption model and density of states are for Comparative Example 8. Detailed Implementation

[0067] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0068] Example 1

[0069] This embodiment provides a dibenzofuranylcarbazole derivative (compound A1) and its preparation method. The synthetic route is as follows:

[0070]

[0071] The preparation method includes the following steps:

[0072] (1) Under a nitrogen atmosphere, the starting material (1.5 g, 3.0 mmol) and diethyl-4-bromobutylphosphonic acid (0.91 g, 3.1 mmol) were dissolved in 25 mL of N,N-dimethylacetamide, followed by the addition of K2CO3 (0.83 g, 6.0 mmol) and cuprous iodide (0.06 g, 6.0 mmol). The reaction mixture was heated at 180 °C. o The reaction was carried out at C for 24 h. After the reaction was completed, the mixture was cooled to room temperature, diluted with water, extracted with dichloromethane, and the organic layer was dried over anhydrous magnesium sulfate and filtered to dryness. The crude product was separated by silica gel column chromatography to give 1.02 g of white solid intermediate I, in 49% yield.

[0073] Intermediate I was characterized by 1H NMR spectroscopy, and the results are as follows: Figure 1 As shown, its NMR data is as follows:

[0074] 1H NMR (400 MHz, DMSO-d6) δ 8.34 (d, J = 2.2 Hz, 2H), 8.16 (dd, J =2.1, 0.9 Hz, 2H), 8.07-7.99 (m, 2H), 7.68 (d, J = 6.9 Hz, 1H), 7.59-7.43 (m,11H), 7.38 (td, J = 8.9, 1.5 Hz, 2H), 4.14 (t, J = 5.1 Hz, 2H), 3.99 (dq, J =8.5, 7.3 Hz, 4H), 1.92 (dtd, J = 11.8, 8.7, 0.6 Hz, 2H), 1.84-1.73 (m, 2H), 1.68-1.56 (m, 2H), 1.30 (td, J = 7.3, 0.7 Hz, 6H).

[0075] (2) In a 50 mL dry round-bottom flask, intermediate I (0.70 g, 1 mmol) was dissolved in 20 mL of dichloromethane. At room temperature, trimethylbromosilane (0.612 g, 0.528 mL, 4 mmol) was added dropwise to the well-stirred mixture. After 12 h, the mixture was carefully transferred to a 100 mL round-bottom flask and concentrated under reduced pressure. Then, a magnetic stir bar and 20 mL of methanol were added sequentially, and the mixture was stirred at room temperature for 4 h. After filtration, the mixture was washed with methanol (3 × 5 mL) and concentrated under reduced pressure to obtain the crude product. Recrystallization from methanol / dichloromethane / diethyl ether yielded a white solid compound A1, 0.38 g, with a yield of 59%.

[0076] Compound A1 was characterized by 1H NMR spectroscopy, and the results are as follows: Figure 2 As shown, its NMR data is as follows:

[0077] 1 H NMR (400 MHz, DMSO-d6) δ 8.37-8.32 (m, 4H), 8.16 (dd, J = 2.0, 0.9Hz, 2H), 8.07-7.99 (m, 2H), 7.68 (d, J = 6.9 Hz, 1H), 7.59-7.33 (m, 13H), 4.14 (t, J = 5.1 Hz, 2H), 1.93-1.74 (m, 4H), 1.73-1.60 (m, 2H).

[0078] The mass spectrometry data for compound A1 are as follows: MS m / z: [MH] - Theoretical value: [C] 40 H 29 NO5P]- 634.18, measured value: 634.04.

[0079] Example 2

[0080] This embodiment provides a dibenzofuranylcarbazole derivative (compound A2) and its preparation method, the preparation method including the following steps:

[0081] (1) Under a nitrogen atmosphere, the starting materials (1.2 g, 3.0 mmol) and diethyl-4-bromobutylphosphonic acid (0.90 g, 3.3 mmol) were dissolved in 25 mL of N,N-dimethylacetamide, followed by the addition of K₂CO₃ (0.83 g, 6.0 mmol) and cuprous iodide (0.06 g, 6.0 mmol). The reaction mixture was heated at 170 °C. o The reaction was carried out at C for 20 h. After the reaction was completed, the mixture was cooled to room temperature, diluted with water, extracted with dichloromethane, and the organic layer was dried over anhydrous magnesium sulfate and filtered to dryness. The crude product was separated by silica gel column chromatography to give 1.19 g of white solid intermediate I, with a yield of 66%.

[0082] (2) In a 50 mL dry round-bottom flask, intermediate I (0.6 g, 1 mmol) was dissolved in 20 mL dichloromethane. At room temperature, trimethylbromosilane (0.612 g, 0.528 mL, 4 mmol) was added dropwise to the well-stirred mixture. After 10 h, the mixture was carefully transferred to a 100 mL round-bottom flask and concentrated under reduced pressure. Then, a magnetic stir bar and 20 mL of methanol were added sequentially, and the mixture was stirred at room temperature for 4 h. After filtration, the mixture was washed with methanol (3 × 5 mL) and concentrated under reduced pressure to obtain the crude product. Recrystallization from methanol / dichloromethane / diethyl ether yielded a white solid compound A2, 0.33 g, with a yield of 60%.

[0083] The mass spectrometry data for intermediate I are as follows: MS m / z: [MH] - Theoretical value: 600.23, measured value: 600.15.

[0084] The mass spectrometry data for compound A2 are as follows: MS m / z: [MH] - Theoretical value: 544.17, measured value: 544.26.

[0085] Example 3

[0086] This embodiment provides a dibenzofuranylcarbazole derivative (compound A3) and its preparation method, the preparation method including the following steps:

[0087] (1) Under a nitrogen atmosphere, the starting materials (1.3 g, 3.0 mmol) and diethyl-4-bromobutylphosphonic acid (0.98 g, 3.6 mmol) were dissolved in 25 mL of N,N-dimethylacetamide, followed by the addition of K₂CO₃ (0.83 g, 6.0 mmol) and cuprous iodide (0.06 g, 6.0 mmol). The reaction mixture was heated at 160 °C. o The reaction was carried out at C for 22 h. After the reaction was completed, the mixture was cooled to room temperature, diluted with water, extracted with dichloromethane, and the organic layer was dried over anhydrous magnesium sulfate and filtered to dryness. The crude product was separated by silica gel column chromatography to give 1.2 g of white solid intermediate I, in 65% yield.

[0088] (2) In a 50 mL dry round-bottom flask, intermediate I (0.43 g, 1 mmol) was dissolved in 20 mL dichloromethane. At room temperature, trimethylbromosilane (0.918 g, 0.791 mL, 6 mmol) was added dropwise to the well-stirred mixture. After 14 h, the mixture was carefully transferred to a 100 mL round-bottom flask and concentrated under reduced pressure. Then, a magnetic stir bar and 20 mL of methanol were added sequentially, and the mixture was stirred at room temperature for 4 h. After filtration, the mixture was washed with methanol (3 × 5 mL) and concentrated under reduced pressure to obtain the crude product. Recrystallization from methanol / dichloromethane / diethyl ether yielded a white solid compound A3, 0.32 g, with a yield of 57%.

[0089] The mass spectrometry data for intermediate I are as follows: MS m / z: [MH] - Theoretical value: 618.22, measured value: 618.18.

[0090] The mass spectrometry data for compound A3 are as follows: MS m / z: [MH] - Theoretical value: 562.16, measured value: 562.09.

[0091] The preparation methods for Examples 4-5 and Comparative Examples 1-8 are the same as those for Example 1, and can be achieved by replacing the raw materials. Therefore, they are not listed one by one. The raw materials and test data for each compound are shown in Tables 1-4:

[0092] Table 1

[0093]

[0094] Table 2

[0095]

[0096] Table 3

[0097]

[0098] Table 4

[0099]

[0100] Application Example 1

[0101] This application example uses a self-assembled monolayer material containing compound A1 as a hole transport layer to fabricate a perovskite solar cell, such as... Figure 4 As shown, its structure is: Glass / FTO / NiOx / SAM / PVSK / C60 / SnO2 / Ag.

[0102] The preparation process is as follows:

[0103] (1) Pretreatment of FTO conductive glass substrate: The FTO glass was ultrasonically cleaned in detergent, deionized water, ethanol and acetone for 15 minutes each, then dried in a 75°C oven and treated with ultraviolet ozone for 10 minutes.

[0104] (2) Preparation of NiOx layer by spin coating: 5 mg / mL NiOx aqueous solution was filtered through a 0.22 μm PTFE filter membrane and then dropped onto the surface of FTO substrate. The substrate was then rotated at 5000 rpm for 30 s on a spin coater and then heat-annealed at 120°C for 15 minutes.

[0105] (3) Preparation of self-assembled monolayer (SAM): After the NiOx was prepared, the substrate was transferred to a nitrogen glove box, and 110 μL of ethanol solution of compound A1 with a concentration of 0.35 mg / mL was dropped onto the center of the substrate. The substrate was spin-coated at 5000 rpm for 30 s and then heat-annealed at 100 °C for 10 min.

[0106] (4) Two-step spin-coating method for depositing perovskite layer: 110 μL of perovskite precursor solution (FA) was applied to the perovskite precursor solution. 0.9 MA 0.05 Cs 0.05 PbI3 (1.5M, DMF:DMSO = 4:1) was dropped onto the center of the substrate. The first step was to spin at 2000 rpm for 20 seconds, and the second step was to spin at 4500 rpm for 35 seconds. 10 seconds before the end of the second spin coating, 110 μL of anisole was dropped onto the center of the substrate at a uniform rate, followed by heat annealing at 110 °C for 20 minutes.

[0107] (5) Preparation of passivation layer: At room temperature, drop 110 μL of 0.5 mg / mL PDADI2 isopropanol solution onto the center of the substrate, rotate it at 5000 rpm for 30 s on a spin coater, and anneal it on a constant temperature hot plate at 100℃ for 5 minutes.

[0108] (6) The battery is transferred to the vapor deposition system, and a 21 nm C60 layer is deposited on the perovskite layer by vacuum thermal evaporation. Then, a 25 nm SnO2 layer is deposited by atomic layer deposition (ALD) at 90 °C. Finally, after scraping off the excess film at the common end, an Ag electrode with a thickness of 100 nm is deposited by vacuum vapor deposition under masked conditions.

[0109] Figure 3 This is the current-voltage (J-V) characteristic curve of the perovskite solar cell device in this application example, where the open-circuit voltage is 1.101V and the short-circuit current density is 25.11mA / cm². 2 The fill factor FF is 0.832 and the photoelectric conversion efficiency is 23.0%.

[0110] This invention uses dibenzofuranylcarbazole as the core, optimizes the ordered molecular stacking, and significantly improves the hole mobility. The terminal phosphate group serves as an anchoring group, which can effectively passivate perovskite interface defects, reduce energy loss at the interface, and enable single-molecule self-assembly, thereby improving battery performance. As a self-assembled monolayer hole transport material, it enables perovskite solar cells to have a high photoelectric conversion efficiency of up to 23.0%, while also exhibiting a long lifespan and stability.

[0111] The energy levels of self-assembled single-molecule hole transport materials were tested in this invention, and the results are shown in Table 5:

[0112] The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the SAM molecule were determined by density functional theory (DFT) calculations and aligned with the vacuum level. The HOMO levels, ranging from -5.0 eV to -6.0 eV, are aligned with the valence band tops of typical perovskite absorbers (e.g., the valence band top of FAPbI3 is approximately -5.4 to -6.0 eV), thus enabling good hole transport. The LUMO levels, located between -1.0 eV and -3.0 eV, provide a sufficient energy barrier for electron injection, thereby reducing charge recombination at the interface.

[0113] Table 5

[0114]

[0115] As shown in Table 5, the compound provided by this invention has a suitable HOMO energy level that matches the valence band top of perovskite, thereby achieving good hole transport; and the LUMO energy level is greater than the conduction band bottom of perovskite, preventing electron injection into perovskite, thus improving the photoelectric conversion efficiency of perovskite photovoltaic devices containing the compound of this invention.

[0116] This invention uses a heterointerface transport model to more accurately describe the carrier (electron and hole) transfer behavior at the SAM molecule-perovskite heterointerface. When the highest occupied molecular orbital (HOMO) energy level of the SAM molecule is higher than the perovskite valence band top (VBM), electrons from the SAM molecule will transfer to the lower-energy perovskite valence band. Equivalently, holes from the perovskite will transfer to the SAM, thus realizing hole transport.

[0117] First-principles DFT simulations were used to calculate the density of states (DOS) of each SAM molecule adsorbed on the perovskite interface to elucidate the electronic structure and interfacial interactions. The calculations were performed using Vienna Ab initio simulation software package version 6.4.2, employing a hybrid functional approach to balance computational efficiency with the accuracy of describing the band gap and localized states. The simulation workflow is as follows:

[0118] Model Construction: A perovskite surface model was constructed using a FAPbI3 unit cell (3x3x1) with PbI2 capping on its (001) facets. SAM molecules were adsorbed through their functional groups. Van der Waals interactions were introduced using DFT-D3 correction to explain non-covalent bonding. Periodic boundary conditions were applied, and a vacuum layer of at least 20 Å was placed perpendicular to the interface to mitigate spurious interactions.

[0119] Geometric optimization: Initial structural relaxation was performed using the Generalized Gradient Approximation (GGA) and the Perdew-Burke-Ernzerhof (PBE) function. A plane-wave basis set with an energy cutoff of 400 eV was used, and the Brillouin zone was sampled using a 3×3×1 gamma-centered k-point grid. The core electron was treated with a Projected Enhanced Wave (PAW) pseudopotential, whose valence configuration includes the 5d Pb. 10 6s 2 6p 2 ,I's 5s 2 5p 5 And the corresponding settings for organic elements. The electronic self-consistent convergence criterion is set to 10. -5 eV, with the ionic force convergence criterion set at 0.02 eV / Å.

[0120] Electronic structure calculations: After optimization, single-point energies were calculated using the hybrid Heyd-Scuseria-Ernzerhof (HSE06) functional, which incorporates 25% accurate Hartree-Fock exchange and is screened with a parameter of 0.2 Å. -1 This hybrid approach corrects the inherent bandgap underestimation problem of pure GGA functionals, thus providing a more reliable DO spectrum.

[0121] Density of states calculation: The total density of states and projected density of states (PDOS) were calculated using the tetrahedral method, and Bloch correction was performed to eliminate dispersion effects, thus ensuring a high-resolution description of states near the Fermi level. The DOS was calculated from -10 eV to +5 eV relative to the Fermi level, with a grid spacing of 0.01 eV. The contributions of SAM molecules, perovskite lattice, and interface atoms to the PDOS were analyzed to identify hybridization effects, such as orbital overlap between the SAM π-conjugated system and the perovskite valence band states.

[0122] This calculation scheme reveals key interfacial electronic properties, including the bandgap mid-states generated by the SAM-perovskite interaction and the shift in the effective work function, which are crucial for improving the open-circuit voltage and fill factor of solar cells.

[0123] Depend on Figures 5-17 It is known that the compounds A1 to A5 of the present invention have suitable HOMO energy levels, which form an energy level difference with the valence band top (VBM) of perovskite, which is conducive to the transport of holes from perovskite to SAM material, thereby improving the photoelectric conversion efficiency of perovskite photovoltaic devices containing the compounds of the present invention.

[0124] Comparative Examples 1 and 3, adsorbed onto the perovskite crystal surface, resulted in severe structural distortion of the perovskite-SAM composite, indicating that Comparative Examples 1 and 3 cannot be adsorbed and therefore cannot serve as hole transport materials. Comparative Example 2, adsorbed onto the perovskite crystal surface, exhibited a uniform density of states (DOS) distribution, failing to form an effective heterostructure. Comparative Examples 4, 5, and 8, adsorbed onto the perovskite crystal surface, had HOMO levels lower than the valence band top (VBM) of perovskite, preventing hole transport from perovskite to the SAM material. Comparative Example 7, adsorbed onto the perovskite crystal surface, had a HOMO level comparable to the valence band top of perovskite, failing to create an energy level difference and hindering hole transport from perovskite to the SAM material. Comparative Example 6, adsorbed onto the perovskite crystal surface, had a HOMO level higher than the conduction band top (CBM) of perovskite, preventing hole transport from perovskite to the SAM material.

[0125] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A dibenzofuranylcarbazole derivative, characterized in that, The dibenzofuranylcarbazole derivative has the structure shown in Formula I: ； Wherein, R1 is selected from any of the following structures: 、 、 、 、 ； Dashed lines indicate connection points.

2. A method for preparing the dibenzofuranylcarbazole derivative as described in claim 1, characterized in that, The preparation method includes the following steps: (1) The starting material is reacted with diethyl-4-bromobutylphosphonic acid to obtain intermediate I; ； (2) Intermediate I undergoes a hydrolysis reaction to obtain the dibenzofuranylcarbazole derivative; ； R1 has the same choice as claim 1.

3. The preparation method according to claim 2, characterized in that, In step (1), the molar ratio of the starting material to diethyl-4-bromobutylphosphonic acid is 1: (1-1.2); In step (1), the reaction is carried out in a solvent; In step (1), the solvent includes N,N-dimethylacetamide; In step (1), the reaction is carried out in the presence of a catalyst; In step (1), the catalyst comprises cuprous iodide; In step (1), the reaction is carried out in the presence of an alkaline substance; In step (1), the alkaline substance includes potassium carbonate and / or sodium carbonate; In step (1), the reaction temperature is 160-180℃; In step (1), the reaction time is 20-24 h; In step (2), the hydrolysis reaction is carried out in the presence of trimethylbromosilane; The molar ratio of trimethylbromosilane to intermediate I is (2-4):1; In step (2), the hydrolysis reaction is carried out in an organic solvent, which is selected from dichloromethane and / or trichloromethane; In step (2), the hydrolysis reaction is carried out at room temperature for 12-18 h.

4. A perovskite solar cell, characterized in that, The perovskite solar cell includes a self-assembled monolayer, which includes the hole transport material based on the dibenzofuranylcarbazole derivative as described in claim 1.

5. The perovskite solar cell according to claim 4, characterized in that, The perovskite solar cell is an inverted perovskite solar cell. The perovskite solar cell includes a cathode layer, an electron transport layer, a passivation layer, a perovskite light-absorbing layer, a self-assembled monolayer, and an anode layer. And / or, the perovskite solar cell further includes a hole transport layer located between the self-assembled monolayer and the anode layer.

6. The perovskite solar cell according to claim 5, characterized in that, The self-assembled monolayer is obtained by coating a solution of the self-assembled monolayer hole transport material based on dibenzofuranylcarbazole derivative as described in claim 1 onto the surface of a hole transport layer and then performing thermal annealing.

7. The perovskite solar cell according to claim 6, characterized in that, The heat annealing temperature is 80-120℃, and the heat annealing time is 5-20 min.

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