Organic hole transport material and use thereof, perovskite solar cell

Abstract

The application provides an organic hole transport material, application thereof, and a perovskite solar cell. The organic hole transport material has a structural formula as shown in formula (I), and R is independently selected from C 2‑6 alkenyl, C 2‑6 alkynyl, C 1‑6 alkyl or halogen, and at least one R is C 2‑6 alkenyl, C 2‑6 alkynyl or halogen; and n is an integer from 1 to 4. The self-assembled organic hole transport material has excellent performance and high light transmittance by introducing a substituted phenyl and a mother nucleus for synergistic effect of conjugation. When an unsaturated group such as alkenyl or alkynyl, especially a vinyl end group, is introduced into the substituted phenyl, in-situ crosslinking can be achieved, migration of the organic hole transport material to a light absorption layer during device operation is effectively inhibited, the stability of the molecule is improved, and the heat resistance, long-term stability and other performances of the perovskite solar cell device are greatly improved.

Description

Technical Field

[0001] This invention relates to the field of perovskite solar cell technology, specifically to an organic hole transport material and its applications, and perovskite solar cells. Background Technology

[0002] As the most fundamental material basis for human societal development, energy demand has surged due to the rapid development of emerging industries driven by a new wave of technological advancements. The non-renewable nature and potential pollution risks of fossil fuels have compelled countries worldwide to vigorously explore and develop clean and environmentally friendly new energy sources. Among these new energy sources, solar energy has gained significant popularity due to its inexhaustible availability and wide applicability, leading to substantial progress in photovoltaic technology. Currently, silicon-based solar cells dominate the photovoltaic industry, but they still face challenges such as high production costs, energy-intensive manufacturing, and environmental pollution. Therefore, researchers are dedicated to developing more affordable and efficient perovskite solar cells to promote the widespread application of clean solar energy.

[0003] Common perovskite solar cells (PSCs) consist of a conductive glass substrate, an electron transport layer (ETL), a perovskite layer, a hole transport layer (HTL), and metal electrodes. Based on the deposition order of the charge transport layers during device fabrication, PSCs can be classified into two types: upright (nip) and inverted (pin). Their working principle can be summarized as follows: after the perovskite layer absorbs photon energy, electrons in the valence band undergo transitions to form electron-hole pairs. These pairs move under the influence of a built-in electric field and are collected by the electrodes to generate current. Currently, the photoelectric conversion efficiency (PCE) of pin devices has surpassed that of nip devices, and they possess unique advantages such as low hysteresis, mild fabrication conditions, and the ability to construct multilayer devices, thus attracting widespread research.

[0004] In pin PSCs, high-temperature sulfonate (HTL) is a crucial component, playing a role not only in selectively extracting and transporting holes but also influencing the quality of the perovskite layer as a growth substrate, thus significantly impacting device efficiency and stability. Currently, the most widely used HTL materials in pin PSCs are poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS). PTAA is relatively expensive (>2000 RMB / gram) and has poor surface wettability, hindering large-scale applications; while PEDOT:PSS suffers from acidity and corrosiveness, compromising long-term device stability. These issues restrict the further development of pin PSCs, making the development of inexpensive, efficient, and stable novel HTL materials particularly important.

[0005] Among the many types of novel high-performance liquid chromatography (HTL) materials, self-assembled single-layer (SAMs) materials with anchoring groups (carboxylic acid groups, phosphonic acid groups, etc.) show potential for commercial applications. These materials possess unique advantages such as simple synthesis, good batch-to-batch reproducibility, and significant passivation effects. They can spontaneously anchor onto metal oxide surfaces to regulate interfacial energy level alignment and also exhibit high light transmittance, thus significantly improving the open-circuit voltage (V0.05) of devices. OC ) and short-circuit current (J SC However, small-molecule SAMs still suffer from poor stability and are prone to migration under stresses such as light and heat, leading to a decline in device performance. Therefore, solving this problem with small-molecule SAMs is crucial for advancing the commercialization of SAMs-based pin PSCs. Consequently, developing a hole transport material to enhance molecular stability and thus improve the long-term stability of perovskite solar cell devices is a pressing technical challenge. Summary of the Invention

[0006] To address the above problems, this invention provides an organic hole transport material and its applications, as well as a perovskite solar cell.

[0007] On the one hand, the present invention provides an organic hole transport material, the structural formula of which is shown in formula (I):

[0008]

[0009] In this case, R is independently selected from C. 2-6 alkenyl, C 2-6 alkynyl group, C 1-6 Alkyl or halogen, and at least one R is C 2-6 alkenyl, C 2-6 Alkyne or halogen; n is an integer from 1 to 4.

[0010] On the other hand, the present invention also provides the use of the above-mentioned organic hole transport material as a hole transport material for perovskite solar cells.

[0011] In another aspect, the present invention provides a perovskite solar cell comprising a hole transport layer, wherein the hole transport layer comprises the aforementioned organic hole transport material.

[0012] Beneficial effects:

[0013] (1) The present invention provides a self-assembled organic hole transport material with carbazole or its fused ring conjugated extended derivative as the parent core and carboxylic acid group as the anchoring group. By introducing substituted phenyl groups to conjugate with the parent core, the material has excellent performance and high light transmittance.

[0014] (2) The introduction of halogens, especially F, into the substituted phenyl group can greatly improve the hydrophobicity of organic hole transport materials and their affinity for perovskite precursor solutions, and synergistically enhance hole transport performance with the parent nucleus and phenyl group.

[0015] (3) Introducing unsaturated groups such as alkenyl, alkynyl, and especially ethylene end groups into the substituted phenyl group, and extending alkenyl functionalization through host conjugation, can achieve in-situ crosslinking through heat treatment (such as annealing), effectively inhibiting the migration of organic hole transport materials to the light-absorbing layer during device operation, improving molecular stability, and greatly improving the heat resistance stability, long-term stability and other performance of perovskite solar cell devices.

[0016] (4) The organic hole transport material of the present invention has good solubility and film-forming properties, which has a significant impact on the microstructure and hole transport capability of the buried interface of the perovskite layer, and is conducive to the formation of high-quality perovskite thin films with reduced surface defects and improved interface contact.

[0017] (5) Furthermore, when unsaturated groups such as alkenyl, alkynyl, and especially ethylene end groups are introduced into the substituted phenyl groups in organic hole transport materials, the in-situ thermally crosslinked SAMs layer can effectively suppress nonradiative recombination at the interface and reduce interfacial energy loss. When halogens such as F are introduced into the substituted phenyl groups simultaneously, the hydrophobicity and the affinity of the perovskite precursor solution can be enhanced synergistically. Based on this, the inverted conventional bandgap perovskite solar cell of this type of organic hole transport material can achieve a high photoelectric conversion efficiency of 23.64%, showing great application potential, and the long-term stability of the perovskite solar cell device is also significantly improved. Attached Figure Description

[0018] Figure 1 The solution UV-Vis transmission contrast spectra of compound HFCB-OH synthesized in Example 1, compound FCB-OH synthesized in Example 3, and commercial compound MeO-2PACz are shown below.

[0019] Figure 2 The current-voltage (JV) characteristic curve of perovskite solar cells prepared by using the compound HFCB-OH synthesized in Example 1 of this invention as a hole transport material;

[0020] Figure 3 The current-voltage (JV) characteristic curve of perovskite solar cells prepared by using the compound HCB-OH synthesized in Example 2 of this invention as a hole transport material;

[0021] Figure 4 The current-voltage (JV) characteristic curve of perovskite solar cells prepared by using the compound FCB-OH synthesized in Example 3 of this invention as a hole transport material;

[0022] Figure 5 The current-voltage (JV) characteristic curve of perovskite solar cells prepared by using compound 3,6HCB-OH synthesized in Example 4 of this invention as a hole transport material;

[0023] Figure 6 The current-voltage (JV) characteristic curve of perovskite solar cells prepared by using the compound HDB-OH synthesized in Example 5 of this invention as a hole transport material;

[0024] Figure 7 The current-voltage (JV) characteristic curves of perovskite solar cells fabricated based on the commercial compound MeO-2PACz as a hole transport material are shown.

[0025] Figure 8 This is a schematic diagram of the structure of the organic-inorganic lead halide perovskite solar cell prepared in Application Example 1 of the present invention;

[0026] Figure 9 The contact angle between the hole transport layer prepared by the three materials of the present invention—compound HFCB-OH synthesized in Example 1, compound FCB-OH synthesized in Example 3, and commercial compound MeO-2PACz—and water and perovskite precursor solutions;

[0027] Figure 10 The images show X-ray diffraction patterns of perovskite crystals in three perovskite films deposited on hole transport layers prepared by the synthetic compounds HFCB-OH (Example 1), FCB-OH (Example 3), and the commercial compound MeO-2PACz. Detailed Implementation

[0028] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present application will become clearer and more apparent.

[0029] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0030] In this invention, the term "MA" represents CH3NH3. + ;

[0031] In this invention, the term "FA" represents HC(NH2)2. + ;

[0032] In this invention, the term "BCP" represents 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline.

[0033] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0034] On the one hand, the present invention provides an organic hole transport material, the structural formula of which is shown in formula (I):

[0035]

[0036] In this case, R is independently selected from C. 2-6 alkenyl, C 2-6 alkynyl group, C 1-6 Alkyl or halogen, and at least one R is C 2-6 alkenyl, C 2-6 Alkyne or halogen; n is an integer from 1 to 4.

[0037] It should be noted that the organic hole transport material of the present invention uses carbazole (9H-carbazole) or conjugated extended dibenzo[c,g]carbazole (fused ring conjugated carbazole, 7H-dibenzo[c,g]carbazole) skeleton as the parent core, carboxyl group as anchoring group, and introduces R-substituted phenyl groups as shown in formula (I). The R-substituted phenyl groups can conjugate with the parent core to enhance the effect. Perovskite solar cells prepared using the organic hole transport material provided by the present invention have excellent performance and good long-term stability.

[0038] In one embodiment of the organic hole transport material of the present invention, the structural formula of the organic hole transport material is shown in formula (II) or formula (III) below:

[0039]

[0040] It should be noted that Formula (II) uses 9H-carbazole as the parent nucleus, and Formula (III) uses 7H-dibenzo[c,g]carbazole as the parent nucleus, with R-substituted phenyl introduced symmetrically. Compounds with such structures can improve the performance of the prepared perovskite solar cells as organic hole transport materials, especially improving the long-term stability of the devices.

[0041] In the first embodiment of the organic hole transport material of the present invention, n is 1, and R is selected from C. 2-4 alkenyl, C 2-4 The group is alkynyl or halogen, and R is preferably vinyl, ethynyl or F.

[0042] It should be noted that when R is a halogen, such as F, it can improve the hydrophobicity of the organic hole transport material and its affinity for the perovskite precursor solution, which is beneficial to improving the long-term stability of the fabricated device and enabling the device to maintain high photoelectric conversion efficiency and other performance characteristics for a longer period of time; when R is C... 2-4 alkenyl or C 2-4 When the alkynyl group is terminal vinyl, the terminal vinyl group can be thermally crosslinked. In this case, the organic hole transport material has both self-assembly and thermal crosslinking functions, which can effectively suppress the migration of the organic hole transport material to the light-absorbing layer during device operation, greatly improve the thermal stability and other properties of the perovskite solar cell device, and enable the device to maintain high photoelectric conversion efficiency for a longer period of time.

[0043] In the first embodiment of the organic hole transport material of the present invention, the organic hole transport material is selected from the following structural formula:

[0044]

[0045] It should be noted that in this embodiment where n is 1, under the premise of controlling the core structure and R selected from the substituents as described above, the substitution position of R in the phenyl and the substitution position of R-substituted phenyl in the carbazole are cleverly controlled in combination. The performance of the resulting organic hole transport material with the structure of formula (Ⅱ-I)-formula (Ⅲ-Ⅱ) is further greatly improved, which can further improve the long-term stability and photoelectric conversion efficiency of the prepared device, and the device maintains high photoelectric conversion efficiency for a longer period of time.

[0046] In the second embodiment of the organic hole transport material of the present invention, n is 2, and the organic hole transport material is selected from the following structural formula:

[0047]

[0048] Among them, R1 is selected from C 2-6 alkenyl or C 2-6 Alkyne group, preferably from C 2-4 alkenyl or C 2-4 Alkyne group, more preferably vinyl or ethynyl group, especially vinyl;

[0049] R2 is selected from halogen or C. 1-4 Alkyl group, preferably F or methyl.

[0050] It should be noted that in this embodiment where n is 2, by controlling the substitution positions of R1 and R2 in the phenyl group as described above, and by selecting R1 from the above-mentioned unsaturated groups, especially vinyl groups, and R2 from halogens or alkyl groups, especially F or methyl groups, the organic hole transport material has good hydrophobicity and good affinity with perovskite precursor solutions. Furthermore, the organic hole transport material can be cross-linked in situ during high-temperature annealing, which significantly improves the stability, photoelectric conversion efficiency, and other performance of the device.

[0051] In the second embodiment of the organic hole transport material of the present invention, the organic hole transport material is selected from the following structural formula:

[0052]

[0053]

[0054] It should be noted that formulas (Ⅳ-I), (Ⅳ-II), (Ⅴ-I), and (Ⅴ-II) have 9H-carbazole as the core, with R1 and R2 substituting the phenyl group at positions 2, 7 or 3, 6 for di-substitution. Formulas (Ⅵ-I) and (Ⅶ-I) have 7H-dibenzo[c,g]carbazole as the core, with R1 and R2 substituting the phenyl group at positions 5, 9 for di-substitution.

[0055] It should be noted that in this embodiment where n is 2, under the premise of controlling the substitution positions of R1 and R2 in the phenyl group and selecting R1 and R2 from the radical group as described above, controlling the substitution positions of R1 and R2 in the carbazole group results in an organic hole transport material with the structure of formula (Ⅳ-I)-(Ⅶ-I). The R1, R2, phenyl and carbazole cores have better synergistic effects. The organic hole transport material not only has better hydrophobicity and perovskite precursor solution affinity, but also better self-crosslinking. The photoelectric conversion efficiency and stability of the prepared device are further significantly improved.

[0056] In the third embodiment of the organic hole transport material of the present invention, n is 3 or 4, and the organic hole transport material is selected from the following structural formula:

[0057]

[0058] Among them, R1 is selected from C 2-6 alkenyl or C 2-6 Alkyne group, preferably from C 2-4 alkenyl or C 2-4 Alkyne group, more preferably vinyl or ethynyl group, especially vinyl;

[0059] m is 2 or 3, and R3 is independently selected from C. 1-4 Alkyl or halogen, preferably methyl or F.

[0060] In one embodiment of the organic hole transport material of the present invention, the organic hole transport material is selected from the following compounds and combinations thereof:

[0061]

[0062] It should be noted that the hole transport layer prepared with the above compounds has high light transmittance, good hydrophobicity, and good affinity with perovskite precursor solutions. In particular, when the substituted phenyl groups in the compounds have terminal vinyl groups, in-situ crosslinking can be achieved through heat treatment (such as annealing). The long-term stability of the resulting perovskite solar cell device is significantly improved, and it can maintain a high photoelectric conversion efficiency for a longer period of time.

[0063] In addition, the present invention can also provide a method for synthesizing the above-mentioned organic hole transport material, which may include the following steps:

[0064] (1) S1. Under the reaction conditions of N,N-dimethylformamide (DMF) as solvent, cuprous iodide as catalyst, 1,10-phenanthroline as ligand and potassium carbonate as base, dibromo-9H-carbazole (CZ) reacts with methyl iodobenzoate to generate dibromocarbazole methyl benzoate derivative (CZ-Me).

[0065]

[0066] T1. Under reaction conditions of N,N-dimethylformamide (DMF) as solvent, cuprous iodide as catalyst, 1,10-phenanthroline as ligand, and potassium carbonate as base, 7H-dibenzo[c,g]carbazole (DCB) reacts with methyl iodobenzoate to generate methyl 4-(7H-dibenzo[c,g]carbazole)benzoate (DCB-Me);

[0067]

[0068] T2. In a mixed solution of DMF and chloroform (CF), DCB-Me reacts with N-bromosuccinimide (NBS) to prepare a dibromobenzocarbazole methyl benzoate derivative (BrDCB-Me);

[0069]

[0070] (2)a. Under nitrogen protection, methyl carbazole benzoate derivatives (BrCZ: including CZ-Me prepared by S1 and BrDCB-Me prepared by T2) were reacted with 3-fluoro-4-carboxyphenylboronic acid, 4-vinylphenylboronic acid, or 3-fluorophenylboronic acid to prepare end-group modified methyl carbazole benzoate derivatives (CZ-OMe) by the Suzuki reaction.

[0071]

[0072] When 9H-carbazole is used as the core, R1 is -CHO and R2 is -F, or R1 is -CH=CH2 and R2 is -H, or R1 is -H and R2 is -F; when 7H-dibenzo[c,g]carbazole (DCB) is used as the core, R1 is -CH=CH2 and R2 is -H.

[0073] b. When the product CZ-OMe from step a has the structure of methyl 4-(2,7-bis(3-fluoro-4-formylphenyl)-9H-carbazole-9-yl)benzoate (HFCB-CHO) (R1 is formyl-CHO, R2 is -F), the formyl group at position R1 needs to be converted to a vinyl group using the Wittig reaction to obtain the derivative (HFCB-Me).

[0074]

[0075] (3) Using tetrahydrofuran / water (10:1, v / v) as a mixed reaction solvent, the end-group modified carbazole benzoate methyl ester derivative CZ-OMe was hydrolyzed under alkaline catalysis to prepare carboxyl-substituted SAM molecules CZ-OH.

[0076]

[0077] When 9H-carbazole is used as the core, R1 is -CHO and R2 is -F, or R1 is -CH=CH2 and R2 is -H, or R1 is -H and R2 is -F; when 7H-dibenzo[c,g]carbazole (DCB) is used as the core, R1 is -CH=CH2 and R2 is -H.

[0078] Preferably, in steps (1) S1 and T1, the molar equivalent of methyl 4-iodobenzoate relative to dibromo-9H-carbazole or 7H-dibenzo[c,g]carbazole is 1-2 eq., more preferably 1.8 eq., and even more preferably 1.2 eq. The molar equivalents of cuprous iodide, 1,10-phenanthroline, and potassium carbonate relative to dibromo-9H-carbazole or 7H-dibenzo[c,g]carbazole are 0.25 eq., 0.25 eq., and 1.8 eq., respectively. In this step, the reaction solvent can be DMF or toluene, with DMF being more preferred.

[0079] Preferably, in steps (1) S1 and T1, the reaction temperature is 90°C and the reaction time is 8-24h, more preferably the reaction time is 10-24h, and even more preferably the reaction time is 12-24h.

[0080] Preferably, in steps (1) S1 and T1, after the reaction is completed, post-processing is performed. The specific method is to remove the solvent by rotary evaporation and then purify by silica gel column chromatography using a petroleum ether / dichloromethane mixture with a volume ratio of 2:1 or 3:1.

[0081] Preferably, in step (1) T2, the molar equivalent of N-bromosuccinimide (NBS) relative to DCB-Me is 2 to 5 eq., more preferably 4.5 eq. In this step, the reaction solvent can be DMF / CF (1:1, v / v).

[0082] Preferably, in step (1) T2, the reaction temperature is 0℃ and the reaction time is 10-12h. After the reaction is completed, post-processing is performed. The specific method is as follows: pour the solution after the reaction into 500mL of petroleum ether and stir continuously, filter, and collect the solid precipitate; then, disperse with dichloromethane and collect the solid product by reprecipitation with petroleum ether.

[0083] Preferably, in step (2)a, the molar equivalent of arylboronic acid to the methyl dibromobenzoate derivative is 2-4 eq., more preferably 2-3 eq. The molar equivalents of tetraphenylphosphine palladium and sodium carbonate to the dibromocarbazole benzoate derivative are 0.04-0.07 eq., such as 0.05 eq. and 5-7 eq., respectively. In this step, sodium carbonate is a 30% (w / w) aqueous solution; alternatively, sodium carbonate can be replaced with an equivalent amount of potassium carbonate. The reaction solvent is a mixture of toluene and ethanol.

[0084] Preferably, in step (2)a, the reaction temperature is 110°C and the reaction time is 8-24h, more preferably the reaction time is 10-20h, and even more preferably the reaction time is 12-20h.

[0085] Preferably, in step (2)a, after the reaction is completed, post-processing is performed. The specific method is as follows: after removing the solvent by vacuum distillation or rotary evaporation, purification is carried out by silica gel column chromatography using a petroleum ether / dichloromethane mixture with a volume ratio of 1:1-3:1 or dichloromethane.

[0086] Preferably, in step (2)b, the molar equivalent of methyltriphenylphosphine bromide and potassium tert-butoxide relative to the carbazole benzoate derivative is 2-3 eq., more preferably 2-2.5 eq., and even more preferably 2.1-2.5 eq., and in this step, the reaction solvent is tetrahydrofuran.

[0087] Preferably, in step (2)b, the order of adding materials is as follows: first add potassium tert-butoxide, then add tetrahydrofuran, and finally add methyltriphenylphosphine bromide; or first add methyltriphenylphosphine bromide, then add tetrahydrofuran, and finally add potassium tert-butoxide. The reaction temperature is 0°C, and after the materials are added, the reaction is carried out at room temperature for 8-24 hours. A more preferred reaction time is 10-20 hours, and a further preferred reaction time is 12-20 hours.

[0088] Preferably, in step (2)b, after the reaction is completed, post-processing is performed. The specific method is as follows: after removing the solvent by rotary evaporation, purification is carried out by silica gel column chromatography using petroleum ether / dichloromethane (1:1, v / v) elution buffer.

[0089] Preferably, in step (3), the molar equivalent of sodium hydroxide used relative to the methyl benzoate derivative is 2-7 eq., more preferably 2.5-7 eq., and even more preferably 3-7 eq. The sodium hydroxide used is a 5% aqueous solution, and in this step, the reaction solvent is a mixture of tetrahydrofuran and water.

[0090] Preferably, in step (3), the reaction temperature is 80°C and the reaction time is 8-24h, more preferably the reaction time is 10-20h, and even more preferably the reaction time is 10-18h.

[0091] Preferably, the specific method for post-processing in step (3) is as follows: remove part of the solvent by rotary evaporation, add deionized water and then add concentrated hydrochloric acid dropwise while stirring continuously until pH = 2-4; filter to obtain the solid, wash with water, collect the solid and recrystallize it twice in a mixed solution of tetrahydrofuran and petroleum ether, and filter to obtain the solid as the final product.

[0092] The preparation method of the above-mentioned organic hole transport material of the present invention has simple synthesis steps, low overall preparation cost, is soluble in the green solvent ethanol, and can be applied to large-area solution coating of wide-bandgap or narrow-bandgap perovskite photovoltaic active layers; through in-situ thermal crosslinking, high efficiency and long-term stability of photovoltaic cells can be achieved simultaneously, which is of great significance for promoting the application of perovskite photovoltaics and can realize the mass synthesis of materials.

[0093] On the other hand, the present invention also provides the use of the above-mentioned organic hole transport material as a hole transport material for perovskite solar cells.

[0094] Preferably, the perovskite solar cell employs an optical bandgap (E0). g The structure of a conventional bandgap perovskite light-absorbing layer and pin-inverted device with a voltage of 1.59 eV is described.

[0095] In another aspect, the present invention also provides a perovskite solar cell, which includes a hole transport layer comprising the aforementioned organic hole transport material.

[0096] In one embodiment of the perovskite solar cell of the present invention, the perovskite solar cell includes a conductive glass substrate, the hole transport layer, the perovskite layer, the electron transport layer and the metal electrode.

[0097] The thickness of the hole transport layer is 3-10 nm.

[0098] It should be noted that by using the aforementioned organic hole transport material as the hole transport layer and controlling the thickness of the hole transport layer as described above, the resulting perovskite solar cell exhibits excellent photoelectric conversion efficiency and other properties.

[0099] In one embodiment of the perovskite solar cell of the present invention, the conductive glass substrate is selected from ITO or PEN / ITO;

[0100] The perovskite layer is made of ABX3, where A is selected from CH3NH3. + HC(NH2)2 + Ca 2+ Cs + and Rb + and its combinations; B is selected from Pb 2+ Sn 2+ and Ti 4+ and combinations thereof; X is selected from halide ions and halide-like ions and combinations thereof; the thickness of the perovskite material layer is 500 nm-1 μm;

[0101] The electron transport layer is selected from C60, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), SnO2, TiO2 and combinations thereof, with a thickness of 5-30 nm;

[0102] The metal electrode is selected from Ag electrode, Au electrode or Cu electrode.

[0103] It should be noted that when the electron transport layer consists of multiple combinations, such as including a C60 layer and a BCP layer, "thickness of 5-30 nm" refers to the thickness of each material layer, i.e., the thickness of the C60 layer is 5-30 nm, and the thickness of the BCP layer is 5-30 nm. The organic hole transport material of this invention has wide applicability; various glass substrates, perovskite materials, electron transport layers, and metal electrodes can be matched to prepare high-performance perovskite solar cells.

[0104] In addition, the present invention may also provide a method for preparing the above-mentioned perovskite solar cell, which may include the following steps:

[0105] (1) Clean the glass substrate, such as ITO glass substrate, with glass cleaning solution, deionized water, organic solvents such as acetone and isopropanol, and then dry it with dry compressed air. The cleaned glass substrate is then treated with ultraviolet ozone.

[0106] (2) Mix the hole transport material of the present invention with an organic solvent such as isopropanol to obtain a solution (concentration of 0.2-0.8 mg / mL, preferably 0.5 mg / mL), and then spin-coat it on a glass substrate. The spin-coating can be carried out at 3000-7000 rpm, preferably 5000 rpm, for 20-40 s, preferably 30 s.

[0107] (3) Annealing is performed by heating at 100-120℃, preferably 110℃, for 8-15 minutes, such as 10 minutes, to obtain a hole transport layer; then, after depositing a perovskite thin film, annealing is performed, and an electron transport layer and a metal electrode are vapor-deposited; the electron transport layer preferably includes two layers, such as C60 and BCP.

[0108] The organic hole transport material of the present invention undergoes an annealing process at 100-120°C during the preparation of the hole transport layer. The unsaturated groups in the substituted phenyl groups of the organic hole transport material, such as alkenyl, alkynyl, and especially ethylene end groups, are functionalized by extending the alkenyl group through host conjugation. In-situ crosslinking can be achieved through heat treatment (such as annealing), which effectively inhibits the migration of the organic hole transport material to the light-absorbing layer during device operation, improves molecular stability, and greatly enhances the thermal stability, long-term stability, and other performance of perovskite solar cell devices. The device can maintain high photoelectric conversion efficiency for a longer period of time.

[0109] The present invention will be further described in detail below through examples, but these examples are not intended to limit the invention. In the following examples, unless otherwise specified, the experimental instruments and raw materials involved are all commercially available products.

[0110] Example 1

[0111] Synthesis of 4-(2,7-bis(3-fluoro-4-vinylphenyl)-9H-carbazole-9-yl)benzoic acid (HFCB-OH)

[0112] (1) Compound methyl 4-(2,7-dibromo-9H-carbazole-9-yl)benzoate (CB-Me)

[0113]

[0114] In a 100 mL reaction tube, the following reactants were added sequentially: 2,7-dibromo-9H-carbazole (3.00 g, 9.23 mmol), methyl 4-iodobenzoate (4.35 g, 16.62 mmol), cuprous iodide (439.50 mg, 2.31 mmol), 1,10-phenanthroline (415.87 mg, 2.31 mmol), potassium carbonate (2.30 g, 16.62 mmol), and DMF (50 mL). The mixture was heated to 90 °C under nitrogen protection and stirred for 24 h. After the reaction was complete, the reaction mixture was concentrated azeotropically with ethanol; after evaporation to dryness, it was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 3:1, v / v) to give a white solid CB-Me (3.00 g, 70.75%).

[0115] (2) Methyl 4-(2,7-bis(3-fluoro-4-formylphenyl)-9H-carbazole-9-yl)benzoate (HFCB-CHO)

[0116]

[0117] In a 100 mL three-necked flask, reactants CB-Me (1.00 g, 2.18 mmol), (3-fluoro-4-formylphenyl)boronic acid (1.10 g, 6.53 mmol), toluene (30 mL), ethanol (5 mL), and an aqueous solution of sodium carbonate (3 mL, sodium carbonate content 1.15 g, 10.89 mmol) were added sequentially. Under nitrogen protection, tetrakis(triphenylphosphine) palladium (125.84 mg, 0.11 mmol) catalyst was added, and the mixture was stirred and refluxed at 110 °C for 16 h. After the reaction was complete, the solvent was removed by vacuum distillation; the solution was purified by silica gel column chromatography (eluent: dichloromethane) to give a pale yellow-green solid HFCB-CHO (0.25 g, 21.01%).

[0118] (3) Methyl 4-(2,7-bis(3-fluoro-4-vinylphenyl)-9H-carbazole-9-yl)benzoate (HFCB-Me)

[0119]

[0120] In a 200 mL reaction tube, methyltriphenylphosphine bromide (0.43 g, 1.21 mmol) and 30 mL tetrahydrofuran were added. The mixture was cooled to 0 °C under nitrogen protection and stirred in an ice bath for 10 min. Then, potassium tert-butoxide (0.14 g, 1.21 mmol) was added, and stirring continued for another 10 min. After observing the color change from white to yellow in the reaction tube, HFCB-CHO (0.30 g, 0.55 mmol) was added. After 10 min, the ice bath was removed, and the mixture was allowed to react overnight at room temperature. After the reaction was complete, the solvent was removed by rotary evaporation, and the mixture was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 1:1, v / v) to obtain a white solid HFCB-Me (0.16 g, 53.69%).

[0121] (4) Compound 4-(2,7-bis(3-fluoro-4-vinylphenyl)-9H-carbazole-9-yl)benzoic acid (HFCB-OH)

[0122]

[0123] In a 100 mL three-necked flask, reactant HFCB-Me (0.20 g, 0.37 mmol), tetrahydrofuran (30 mL), and sodium hydroxide aqueous solution (3 mL, sodium hydroxide content 0.06 mg, 1.48 mmol) were added sequentially. The mixture was heated to 80 °C and stirred overnight. After the reaction was complete, some solvent was removed by rotary evaporation. Deionized water was added and stirred continuously. Concentrated hydrochloric acid was added dropwise until the pH of the solution reached 2. The precipitated solid was collected by filtration. The crude product was recrystallized twice in a mixed solution of tetrahydrofuran and petroleum ether to give a white solid HFCB-OH (0.16 g, 84.21%). NMR data 1 H NMR (500MHz, DMSO-d6, δ): 13.19 (s, 1H), 8.38 (d, 2H), 8.26 (d, 2H), 7.93 (d, 2H), 7.79-7.51 (m, 10H), 6.87 (dd, 2H), 5.96 (d, 2H), 5.45 (d, 2H). 13 C NMR(125MHz,DMSO-d6,δ):167.25,161.44,159.47,142.69,142.62,141.33,140.92,137.59,131.96,130.07,128 .98,128.95,128.26,127.13,123.90,123.80,123.69,123.10,121.91,120.45,117.91,114.68,114.50,108.39.

[0124] Example 2

[0125] Synthesis of 4-(2,7-bis(4-vinylphenyl)-9H-carbazole-9-yl)benzoic acid (HCB-OH)

[0126] (1) Compound methyl 4-(2,7-bis(4-vinylphenyl)-9H-carbazole-9-yl)benzoate (HCB-Me)

[0127]

[0128] In a 100 mL three-necked flask, reactants CB-Me (1.50 g, 3.27 mmol), 4-vinylphenylboronic acid (1.21 g, 8.17 mmol), toluene (30 mL), ethanol (5 mL), and an aqueous solution of sodium carbonate (3 mL, sodium carbonate content 1.73 g, 16.33 mmol) were added sequentially. Under nitrogen protection, tetrakis(triphenylphosphine)palladium (264.27 mg, 0.23 mmol) was added. The reaction mixture was heated to 110 °C and refluxed with stirring for 16 h. After the reaction was complete, the solvent was removed by vacuum distillation, and the mixture was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 3:1, v / v) to give a white solid HCB-Me (1.00 g, 60.54%).

[0129] (2) Compound 4-(2,7-bis(4-vinylphenyl)-9H-carbazole-9-yl)benzoic acid (HCB-OH)

[0130]

[0131] In a 100 mL three-necked flask, reactant HCB-Me (0.50 g, 0.99 mmol), tetrahydrofuran (30 mL), and sodium hydroxide aqueous solution (3 mL, sodium hydroxide content 158.21 mg, 3.96 mmol) were added sequentially. The reaction mixture was heated to 80 °C and stirred overnight. After the reaction was complete, some solvent was removed by rotary evaporation, deionized water was added and stirred continuously, while concentrated hydrochloric acid was added dropwise until the solution pH = 2. The precipitated solid was collected by filtration. The crude product was recrystallized twice in a mixed solution of tetrahydrofuran and petroleum ether to give a white solid HCB-OH (0.48 g, 91.43%). NMR data 1 H NMR(500MHz,DMSO-d6,δ):13.19(s,1H),8.35(d,2H),8.26(dd,2H),7.97-7.88( m,2H),7.79-7.61(m,8H),7.56(d,4H),6.78(dd,2H),5.87(d,2H),5.29(d,2H). 13C NMR(125MHz,DMSO-d6,δ):167.22,141.34,141.08,140.59,138.84,136.67,131 .95,130.05,127.77,127.22,127.11,122.73,121.74,120.36,114.89,108.05.

[0132] Example 3

[0133] Synthesis of 4-(2,7-bis(3-fluorophenyl)-9H-carbazol-9-yl)benzoic acid (FCB-OH)

[0134] (1) Compound methyl 4-(2,7-bis(3-fluorophenyl)-9H-carbazole-9-yl)benzoate (FCB-Me)

[0135]

[0136] In a 100 mL three-necked flask, reactants CB-Me (1.00 g, 2.18 mmol), (3-fluorophenyl)boric acid (0.76 g, 5.44 mmol), toluene (30 mL), ethanol (5 mL), and an aqueous solution of sodium carbonate (3 mL, sodium carbonate content 1.15 g, 10.89 mmol) were added sequentially. Under nitrogen protection, tetrakis(triphenylphosphine)palladium (125.84 mg, 0.11 mmol) was added. The reaction system was heated to 110 °C and stirred under reflux for 16 h. After the reaction was complete, the solvent was removed by vacuum distillation; the mixture was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 3:1, v / v) to give a white solid FCB-Me (0.95 g, 89.10%).

[0137] (2) Compound 4-(2,7-bis(3-fluorophenyl)-9H-carbazole-9-yl)benzoic acid (FCB-OH)

[0138]

[0139] In a 100 mL three-necked flask, reactant FCB-Me (0.70 g, 1.43 mmol), tetrahydrofuran (30 mL), and sodium hydroxide aqueous solution (3 mL, sodium hydroxide content 228.78 mg, 5.72 mmol) were added sequentially. The reaction system was heated to 80 °C and stirred overnight. After the reaction was complete, some solvent was removed by rotary evaporation, deionized water was added and stirred continuously, while concentrated hydrochloric acid was added dropwise until the solution pH = 2. The precipitated solid was collected by filtration. The crude product was recrystallized twice in a mixed solution of tetrahydrofuran and petroleum ether to give a white solid FCB-OH (0.65 g, 95.60%). NMR data 1H NMR(500MHz,DMSO-d6,δ):13.19(s,1H),8.39(d,3H),8.27(d,3H),7.94(d,3H),7.73-7.65(m,6H),7.63-7.56(m,6H),7.51(td,3H),7.20(td,3H). 13 C NMR(125MHz,DMSO-d6,δ):167.23,164.14,162.20,143.73,143.67,141.28,140.94,138.07,131.95,131 .34,131.27,130.07,127.10,123.75,123.73,123.03,121.89,120.61,114.63,114.43,114.25,108.61.

[0140] Example 4

[0141] Synthesis of 4-(3,6-bis(4-vinylphenyl)-9H-carbazole-9-yl)benzoic acid (3,6HCB-OH)

[0142] (1) Compound methyl 4-(3,6-dibromo-9H-carbazole-9-yl)benzoate (3,6CB-Me)

[0143]

[0144] In a 100 mL reaction tube, the following reactants were added sequentially: 3,6-dibromo-9H-carbazole (3.00 g, 9.23 mmol), methyl 4-iodobenzoate (4.35 g, 16.62 mmol), cuprous iodide (439.50 mg, 2.31 mmol), 1,10-phenanthroline (415.87 mg, 2.31 mmol), potassium carbonate (2.30 g, 16.62 mmol), and DMF (50 mL). Under nitrogen protection, the mixture was heated to 90 °C and stirred for 24 h. After the reaction was complete, the reaction mixture was concentrated azeotropically with ethanol, evaporated to dryness, and purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 2:1, v / v) to give a white solid 3,6CB-Me (2.80 g, 66.07%).

[0145] (2) Compound methyl 4-(3,6-bis(4-vinylphenyl)-9H-carbazole-9-yl)benzoate (3,6HCB-Me)

[0146]

[0147] In a 100 mL three-necked flask, reactants 3,6CB-Me (1.30 g, 2.83 mmol), 4-vinylphenylboronic acid (1.05 g, 7.08 mmol), toluene (30 mL), ethanol (5 mL), and an aqueous solution of sodium carbonate (3 mL, sodium carbonate content 1.73 g, 16.33 mmol) were added sequentially. Under nitrogen protection, tetrakis(triphenylphosphine)palladium (229.04 mg, 0.20 mmol) was added. The reaction system was heated to 110 °C and stirred under reflux for 16 h. After the reaction was complete, the solvent was removed by vacuum distillation, and the mixture was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 1:1, v / v) to give a white solid 3,6HCB-Me (1.00 g, 60.54%).

[0148] (3) Compound 4-(3,6-bis(4-vinylphenyl)-9H-carbazole-9-yl)benzoic acid (3,6HCB-OH)

[0149]

[0150] In a 100 mL three-necked flask, reactants 3,6HCB-Me (0.30 g, 0.59 mmol), tetrahydrofuran (30 mL), and an aqueous solution of sodium hydroxide (3 mL, sodium hydroxide content 158.21 mg, 3.96 mmol) were added sequentially. The mixture was heated and stirred to 80 °C and reacted overnight. After the reaction was complete, some of the solvent was removed by rotary evaporation. Deionized water was added and stirred continuously. Concentrated hydrochloric acid was added dropwise while stirring until the pH of the solution reached 2. The precipitated solid was collected by filtration. The crude product was recrystallized twice in a mixed solution of tetrahydrofuran and petroleum ether to give a white solid 3,6HCB-OH (0.26 g, 89.14%). NMR data 1 H NMR(500MHz,DMSO-d6,δ):13.22(s,1H),8.79(d,2H),8.25(d,2H),7.82(td,9.0 ,8H),7.60(d,4H),7.56(d,2H),6.80(dd,10.9Hz,2H),5.89(d,2H),5.29(d,2H). 13 C NMR(125MHz,DMSO-d6,δ):167.18,141.19,140.43,140.07,136.76,136.12,132 .96,131.83,129.92,127.23,126.58,125.83,124.57,119.38,114.55,110.87.

[0151] Example 5

[0152] Synthesis of 4-(5,9-bis(4-vinylphenyl)-7H-dibenzo[c,g]carbazole-7-yl)benzoic acid (HDB-OH)

[0153] (1) Compound methyl 4-(2,7-dibromo-9H-carbazole-9-yl)benzoate (DCB-Me)

[0154]

[0155] In a 100 mL reaction tube, the following reactants were added sequentially: 7H-dibenzo[c,g]carbazole (2.4 g, 8.98 mmol), methyl 4-iodobenzoate (2.82 g, 10.77 mmol), cuprous iodide (427.45 mg, 2.24 mmol), 1,10-phenanthroline (404.46 mg, 2.24 mmol), potassium carbonate (2.23 g, 16.16 mmol), and DMF (50 mL). Under nitrogen protection, the mixture was heated to 90 °C and stirred for 24 h. After the reaction was complete, the reaction mixture was concentrated azeotropically with ethanol, evaporated to dryness, and purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 3:1, v / v) to give a white solid, DCB-Me (3.00 g, 83.24%).

[0156] (2) Methyl 4-(5,9-dibromo-7H-dibenzo[c,g]carbazole-7-yl)benzoate (BrDCB-Me)

[0157]

[0158] The raw material DCB-Me (1.0 g, 2.49 mmol) was dissolved in 50 mL of chloroform and poured into a 200 mL reaction tube. After cooling in an ice bath at 0 °C for 10 min, a solution of DMF (50 mL) containing N-bromosuccinimide (2 g, 11.21 mmol) was added dropwise to the reaction flask. Under nitrogen protection, the reaction was continued at 0 °C with stirring for 12 h. After the reaction was completed, the solution was poured into 500 mL of petroleum ether and stirred continuously. The mixture was then filtered and the solid precipitate was collected. The precipitate was dispersed in dichloromethane and reprecipitated with petroleum ether, and the pale pink solid product BBrDCB-Me (1.18 g, 84.71%) was collected.

[0159] (3) Methyl 4-(5,9-bis(4-vinylphenyl)-7H-dibenzo[c,g]carbazole-7-yl)benzoate (HDB-Me)

[0160]

[0161] In a 100 mL three-necked flask, reactants BrdCB-Me (0.50 g, 0.89 mmol), 4-vinylphenylboronic acid (0.26 g, 1.79 mmol), toluene (30 mL), ethanol (5 mL), and an aqueous solution of sodium carbonate (3 mL, sodium carbonate content 0.62 g, 5.85 mmol) were added sequentially. Under nitrogen protection, tetrakis(triphenylphosphine)palladium (51.66 mg, 0.04 mmol) was added. The reaction system was heated to 110 °C and refluxed with stirring for 16 h. After the reaction was complete, the solvent was removed by vacuum distillation, and the mixture was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 1:1, v / v) to give a pale green solid HDB-Me (0.45 g, 83.09%).

[0162] (4) Compound 4-(5,9-bis(4-vinylphenyl)-7H-dibenzo[c,g]carbazole-7-yl)benzoic acid (HDB-OH)

[0163]

[0164] In a 100 mL three-necked flask, reactant HDB-Me (0.43 g, 0.71 mmol), tetrahydrofuran (30 mL), and sodium hydroxide aqueous solution (3 mL, sodium hydroxide content 113.57 mg, 2.84 mmol) were added. The reaction system was heated to 80 °C and stirred overnight. After the reaction was complete, some solvent was removed by rotary evaporation, deionized water was added and stirred continuously, while concentrated hydrochloric acid was added dropwise until the solution pH = 2. The precipitated solid was collected by filtration. The crude product was recrystallized twice in a mixed solution of tetrahydrofuran and petroleum ether to give a white solid product HDB-OH (0.33 g, 78.56%). NMR data 1 H NMR(500MHz,DMSO-d6,δ):13.47-13.11(m,1H),9.19(d,2H),8.24(d,2H),8.02(d,2H), 7.88(d,2H),7.78(t,2H),7.67-7.44(m,12H),6.83(dd,2H),5.91(d,2H),5.33(d,2H). 13 C NMR(125MHz,DMSO-d6,δ):167.07,140.24,140.01,138.82,137.19,136.85,136.71,131.87,131.16 ,130.64,129.17,128.65,128.36,127.47,126.74,126.42,125.35,124.68,116.94,115.17,112.57.

[0165] The structure of the final product in the above embodiments was determined by nuclear magnetic resonance as described above.

[0166] Test Example 1

[0167] The optical properties of the compounds HFCB-OH synthesized in Example 1, FCB-OH synthesized in Example 3, and the commercial compound MeO-2PACz were tested by ultraviolet-visible transmission spectroscopy. The obtained ultraviolet-visible transmission comparison spectra are shown below. Figure 1 As shown.

[0168] The structural formula of the commercial compound MeO-2PACz is shown below:

[0169]

[0170] Figure 1 Ultraviolet-visible transmission spectroscopy shows that the transmittance of the hole transport material FCB-OH is improved by introducing F-substituted phenyl groups onto carbazole. In particular, after introducing F atoms and vinyl-substituted phenyl groups, the carbazole-based hole transport material HFCB-OH exhibits higher transmittance across the entire wavelength range, which can be well matched with the perovskite absorption layer, thus facilitating hole extraction and transport.

[0171] Application Example 1

[0172] <Preparation of Battery Devices>

[0173] Organic-inorganic lead halide perovskite solar cells were prepared using the following compounds as hole transport materials: HFCB-OH synthesized in Example 1, HCB-OH synthesized in Example 2, FCB-OH synthesized in Example 3, 3,6HCB-OH synthesized in Example 4, HDB-OH synthesized in Example 5, and the commercial compound MeO-2PACz.

[0174] Specifically, the battery manufacturing process is as follows:

[0175] The ITO glass substrate was cleaned for 15 min with glass cleaning solution, deionized water, acetone, and isopropanol, and then dried with dry compressed air. The cleaned ITO glass was then treated with ultraviolet ozone for 15 min to improve wettability. A hole transport material was mixed with isopropanol to prepare a concentration of 0.5 mg / mL, and spin-coated onto the ITO substrate at 5000 rpm for 30 s to prepare a hole transport layer. The substrate was then transferred to a glove box and heated at 110°C for 10 min. The perovskite solution was stirred overnight in the glove box, filtered through 0.22 μm polytetrafluoroethylene (PTFE), and a perovskite film was deposited in the glove box using ethyl acetate as the antisolvent. After annealing, C60, BCP, and Ag electrodes were sequentially thermally vapor-deposited. The hole transport layer thickness was 5 nm, the perovskite material layer thickness was 500 nm, the C60 thickness was 30 nm, the BCP thickness was 6 nm, and the Ag electrode thickness was 80 nm.

[0176] The structure of the fabricated perovskite solar cell is as follows: Figure 8 As shown:

[0177] ITO glass / HFCB-OH or HCB-OH or FCB-OH or 3,6HCB-OH or HDB-OH or MeO-2PACz / Cs 0.07 FA 0.9 MA 0.03 Pb(I 0.92 Br 0.08 )3 / C60 / BCP / Ag.

[0178] Characterization of Battery Devices

[0179] The conventional bandgap perovskite solar cell devices prepared using the compounds synthesized in Examples 1-5 and MeO-2PACz as hole transport materials were characterized:

[0180] Using a xenon lamp solar simulator, the light source intensity was tested at AM 1.5G (100mW cm⁻¹). -2 ), for the open-circuit voltage V of the battery device. oc Short-circuit current J sc The fill factor (FF) was tested; battery performance was tested using a Keithley 2400 current-voltage source, and the resulting current-voltage (JV) characteristic curves are shown below. Figure 2-7 .

[0181] like Figure 7 As shown, the photoelectric conversion efficiency of the reference device using the commercial compound MeO-2PACz as a hole transport material is only 22.03%. Under the same conditions, Figure 4The test results for the perovskite solar cell based on the compound FCB-OH synthesized in Example 3 as a hole transport material show a photoelectric conversion efficiency of 23.02%, indicating that the hole transport material with F atoms introduced by carbazole to replace phenyl atoms can improve the performance of the prepared perovskite solar cell. Figure 2 The open-circuit voltage V is the test result of a perovskite solar cell based on the compound HFCB-OH synthesized in Example 1 as a hole transport material. oc The voltage is 1.13V, and the short-circuit current is J. sc 25.12 mA / cm 2 The fill factor (FF) was 83.38%, and the photoelectric conversion efficiency was 23.64%. Using the compound HFCB-OH synthesized in Example 1 as the hole transport material, the phenyl substituent on the carbazole introduced both F atoms and vinyl groups. The cross-linked self-assembled hole transport material HFCB-OH plays a crucial role in improving the performance of perovskite solar cells after cross-linking, resulting in superior overall performance, with not only high photoelectric conversion efficiency but also good long-term stability. The compounds synthesized in the other examples were used to prepare hole transport layers, and the resulting solar cells also exhibited high photoelectric conversion efficiency and good long-term stability.

[0182] Test Example 2

[0183] <Contact Angle Test>

[0184] Hole transport layers with a thickness of 5-10 nm were prepared on ITO glass using the compounds HFCB-OH synthesized in Example 1, FCB-OH synthesized in Example 3, and the commercial compound MeO-2PACz as hole transport materials.

[0185] The preparation process was as follows: The ITO glass substrate was cleaned for 15 minutes with glass cleaning solution, deionized water, acetone, and isopropanol, and then dried with compressed air. The cleaned ITO glass was then treated with ultraviolet ozone for 15 minutes to improve wettability. Hole transport material was mixed with isopropanol to a concentration of 0.5 mg / mL, and then spin-coated onto the ITO substrate at 5000 rpm for 30 seconds. The substrate was then transferred to a glove box and heated at 110°C for 10 minutes to prepare the hole transport layer, yielding the test sample.

[0186] Then, the contact angle between the hole transport layer and water, and between the hole transport layer and the perovskite precursor Cs were measured. 0.07 FA 0.9 MA 0.03 Pb(I 0.92 Br 0.08 The contact angle of the solution (concentration of 1M) was measured, and the test results are shown in [the table below]. Figure 9 As shown.

[0187] The contact angles of three self-assembled hole transport layers on ITO glass with water and perovskite precursor solutions were tested. FCB-OH showed a contact angle of 85.7° with water and 20.6° with the perovskite precursor solution, exhibiting better hydrophobicity and affinity for the perovskite precursor solution compared to commercial MeO-2PACz. HFCB-OH showed a contact angle of 89.1° with water and 13.9° with the perovskite precursor solution; compared to FCB-OH and commercial MeO-2PACz under the same conditions, it exhibited better hydrophobicity and affinity for the perovskite precursor solution. This characteristic is more conducive to the fabrication of large-size perovskite crystals and improved device stability.

[0188] <Device Stability Testing>

[0189] The stability of perovskite crystals prepared on the three self-assembled hole transport layers (HFCB-OH, FCB-OH, and MeO-2PACz) was characterized. Specifically, hole transport layers and perovskite films were sequentially prepared on ITO glass using the same method as in Application Example 1, and then X-ray diffraction analysis was performed on the perovskite crystals in the perovskite film to obtain... Figure 10 The "As prepared" diffraction line in the image shows the X-ray diffraction results after being encapsulated and heated at 100°C for one week in a nitrogen atmosphere. Figure 10 The "1-week" diffraction line in the image.

[0190] Figure 10 X-ray diffraction (as prepared) shows that the perovskite crystal prepared on the HFCB-OH hole transport layer in the newly prepared crystal exhibits a stronger perovskite diffraction signal. X-ray diffraction (1 week) under a nitrogen atmosphere with encapsulation and continuous heating at 100°C clearly shows severe perovskite degradation in commercially available MeO-2PACz. The compounds FCB-OH synthesized in Example 3 and HFCB-OH synthesized in Example 1, when used as perovskites on the hole transport layer, exhibit good stability. Perovskite solar cell devices with better perovskite stability show better long-term stability.

[0191] Furthermore, using the same testing method, hole transport layers were prepared based on compounds HCB-OH synthesized in Example 2, 3,6HCB-OH synthesized in Example 4, and HDB-OH synthesized in Example 5. Perovskite thin films were then deposited on these hole transport layers. X-ray diffraction results of the newly prepared perovskite crystals showed that the perovskite crystals on the hole transport layers formed by the compounds prepared in these examples exhibited stronger perovskite diffraction signals. In particular, after continuous heating for one week, the perovskite showed good stability. Therefore, the long-term stability of perovskite solar cell devices obtained by using the compounds synthesized in the embodiments of this invention as hole transport layers can be significantly improved.

[0192] The present application has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present application based on these embodiments, all of which fall within the protection scope of the present application.

Claims

1. An organic hole transport material, the structural formula of which is shown in formula (I): in, R is independently selected from vinyl or F; n is 1 or 2.

2. The organic hole transport material according to claim 1, wherein, The structural formula of the organic hole transport material is shown in formula (II) or formula (III) below:

3. The organic hole transport material according to claim 1 or 2, wherein, n is 1, and R is vinyl or F.

4. The organic hole transport material according to claim 3, wherein, The organic hole transport material is selected from the following structural formula:

5. The organic hole transport material according to claim 1 or 2, wherein, When n is 2, the organic hole transport material is selected from the following structural formula: Where R1 is vinyl; R2 is F.

6. The organic hole transport material according to claim 5, wherein, The organic hole transport material is selected from the following structural formula:

7. The organic hole transport material according to claim 1, wherein, The organic hole transport material is selected from the following compounds and combinations thereof:

8. Use of the organic hole transport material according to any one of claims 1-7 as a hole transport material for perovskite solar cells.

9. A perovskite solar cell comprising a hole transport layer, wherein, The hole transport layer comprises the organic hole transport material according to any one of claims 1-7.

10. The perovskite solar cell according to claim 9, wherein, The perovskite solar cell includes a conductive glass substrate, a hole transport layer, a perovskite layer, an electron transport layer, and a metal electrode. The thickness of the hole transport layer is 3-10 nm.

11. The perovskite solar cell according to claim 10, wherein, The conductive glass substrate is selected from ITO or PEN / ITO; The perovskite layer is made of ABX3, where A is selected from CH3NH3. + HC(NH2)2 + Ca 2+ Cs + and Rb + and its combinations; B is selected from Pb 2+ Sn 2+ and Ti 4+ and combinations thereof; X is selected from halide ions and halide-like ions and combinations thereof; the thickness of the perovskite material layer is 500 nm-1 μm; The electron transport layer is selected from C60, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, SnO2, TiO2 and combinations thereof, and has a thickness of 5-30 nm. The metal electrode is selected from Ag electrode, Au electrode or Cu electrode.

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