Compound, preparation method, hole transport layer material, photovoltaic device and photovoltaic module

Abstract

The invention relates to a compound, a preparation method, a hole transport layer material, a photovoltaic device and a photovoltaic module. R1 and R4 are respectively and independently selected from amino and derivatives thereof, hydroxyl and derivatives thereof, methoxyl and derivatives thereof, sulfydryl and derivatives thereof, methylthio and derivatives thereof, thiophene groups and derivatives thereof, phosphate groups and derivatives thereof, carboxylic acid groups and derivatives thereof, and sulfonic acid groups and derivatives thereof; r2 and R3 are independently selected from alkyl, a phosphate group and derivatives thereof, a carboxylic acid group and derivatives thereof, a sulfonic acid group and derivatives thereof, and trimethoxysilyl propyl and derivatives thereof. The material is beneficial to improving the photoelectric conversion efficiency of photovoltaic devices and photovoltaic modules.

Description

Technical Field

[0001] This invention relates to a compound, a preparation method, a hole transport layer material, a photovoltaic device, and a photovoltaic module, belonging to the field of photovoltaics. Background Technology

[0002] Since the discovery of the photoelectric effect by French scientist Henri Becquerel in the 19th century, photovoltaic (PV) power generation technology has gradually developed through in-depth research on this effect. Today, PV has become one of the main alternatives to fossil fuels. In recent years, world records for solar cell efficiency have been continuously broken.

[0003] The limiting conversion efficiency of ordinary crystalline silicon solar cells is 29.4%. Currently mass-produced TOPCon and HJT cells can achieve efficiencies of over 25.6% and 26.49%, respectively, approaching the theoretical efficiency limits of TOPCon and HJT cells (28.7% and 27.5%, respectively). Perovskite solar cells, as an emerging photovoltaic technology, demonstrate enormous application potential. The core advantages of this technology lie in its low raw material cost, its ability to be prepared using a low-temperature solution method, and its rapid improvement in photoelectric conversion efficiency. Furthermore, perovskite materials possess unique physical properties such as lightweight, flexibility, and tunable bandgap, making them promising for emerging fields such as building-integrated photovoltaics (BIPV) and flexible electronic devices. Moreover, stacking perovskite with crystalline silicon can further enhance device stability; this stacked structure can absorb a wider range of the solar spectrum, with a theoretical efficiency limit exceeding 43%, far surpassing any single material.

[0004] A typical structure of a perovskite solar cell includes a transparent conductive substrate, an electron transport layer (ETL), a perovskite light-absorbing layer, a hole transport layer (HTL), and a metal electrode. Among these, the hole transport layer plays a crucial role in extracting and transporting photogenerated holes generated in the perovskite layer, blocking electron recombination towards the electrode, and protecting the perovskite layer from external environmental corrosion.

[0005] Currently, the hole transport materials widely used in perovskite solar cells mainly include Spiro-OMeTAD (2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene) and its derivatives. Although Spiro-OMeTAD-based solar cells have achieved high certified efficiencies, they still face a series of serious challenges in practical applications and industrialization:

[0006] (1) Severe interfacial nonradiative recombination: A large number of uncoordinated lead ions (Pb²⁺) and halogen vacancies exist on the surface and at the grain boundaries of the perovskite layer. These defect states become nonradiative recombination centers for charge carriers, trapping photogenerated electrons and holes, resulting in significant losses in open-circuit voltage (Voc) and fill factor (FF), thus limiting further improvements in battery efficiency. Traditional hole transport materials (such as Spiro-OMeTAD) have weak interactions with the perovskite surface, making it difficult to effectively passivate these key defects.

[0007] (2) Interface contact and stability issues: The physical contact and energy level matching between the hole transport layer and the perovskite layer are crucial for efficient hole extraction. Poor interface contact or the presence of energy barriers can lead to interface charge accumulation and severe carrier recombination. In addition, a loose or non-dense HTL cannot effectively block the intrusion of moisture and oxygen, which will also accelerate the decomposition of the perovskite layer and cause rapid degradation of device performance. This is one of the core issues affecting the long-term working stability of perovskite solar cells.

[0008] To address these issues, researchers have attempted to develop novel small molecule or polymer hole transport materials or to molecularly modify Spiro-OMeTAD. However, these improvements often come at the cost of other aspects: some materials, while improving a certain property (such as mobility), still have shortcomings in defect passivation, interface anchoring, or long-term stability; others have complex synthesis procedures and high costs, hindering large-scale production and application.

[0009] Therefore, there is an urgent need in this field to develop a novel hole transport layer material to address the shortcomings of existing hole transport layer materials. Summary of the Invention

[0010] The present invention aims to provide a new compound for use as a hole transport layer material in perovskite solar cells. The hole transport layer formed by this material has good crystallinity and a dense film structure, which can reduce interfacial nonradiative recombination. When applied to perovskite solar cells, the cell efficiency is significantly improved.

[0011] The structural formula of the compound in this invention is as follows:

[0012]

[0013] In the formula: (R1) n R1 represents n substituents, where 0 ≤ n ≤ 4;

[0014] (R2) n This represents n substituents R2, where 0 ≤ n ≤ 3;

[0015] (R3) n This indicates that there are n substituents R3, where 0 ≤ n ≤ 3;

[0016] (R4) n This indicates that there are n substituents R4, where 0 ≤ n ≤ 4;

[0017] (R1) n (R2) n (R3) n (R4) n The values ​​of n can be the same or different;

[0018] R1 and R4 are each independently selected from amino groups and their derivatives, hydroxyl groups and their derivatives, methoxy groups and their derivatives, mercapto groups and their derivatives, methylthio groups and their derivatives, thiophene groups and their derivatives, phosphate groups and their derivatives, carboxylic acid groups and their derivatives, and sulfonic acid groups and their derivatives.

[0019] R2 and R3 are each independently selected from alkyl groups, phosphate groups and their derivatives, carboxylic acid groups and their derivatives, sulfonic acid groups and their derivatives, and trimethoxysilylpropyl groups and their derivatives.

[0020] Preferably, n is always 1, and the structural formula is:

[0021] .

[0022] Further optimization, (R1) n (R4) n In this case, n is always 1, (R²) n (R3) n In this case, n is always 0, and the structural formula is:

[0023] .

[0024] Preferably, R1 and R4 are each independently placed at position 3 or position 4 of the carbazole group. More preferably, R1 and R4 are both dimethylamino, both methoxy, or both phosphate groups.

[0025] Preferably, the hole transport layer material is a combination of one or more of the following:

[0026] ;

[0027] .

[0028] The preparation method of the above-mentioned hole transport layer material is as follows: it is synthesized using raw material one, raw material two, and raw material three, where raw material one is... Raw material two is Raw material three is In the formula, X1 and X2 are the substituents eliminated during the synthesis of raw material one and raw material two, and X3 and X4 are the substituents eliminated during the synthesis of raw material two and raw material three. That is, raw material one and raw material two can undergo the following reaction:

[0029] ;

[0030] The reaction between reactant 3 and reactant 4 can occur as follows:

[0031] ;

[0032] As one option, X1, X2, X3, and X4 are selected from halogenated pinacol esters of borate.

[0033] Photovoltaic devices, such as perovskite cells or other types of photovoltaic cells that require hole transport, can be made using the aforementioned hole transport layer materials. The applicable perovskite cells can be single-junction or tandem, can be inverted or conventional structures, and can be pure perovskite cells or hybrid tandem cells formed by perovskite cells and other types of cells.

[0034] When preparing a hole transport layer using this hole transport layer material, the preferred preparation method is as follows: dissolve the hole transport layer material in an organic solvent to obtain a hole transport layer solution. The concentration of the hole transport layer material is 0.7~2.2 mg / mL. The organic solvent is a mixture of methanol and DMSO (dimethyl sulfoxide), and the volume mixing ratio of methanol to DMSO is methanol:DMSO = (80:20)~(100:0).

[0035] The present invention also provides a photovoltaic module, photovoltaic device, etc., made using the above-mentioned hole transport layer material or the above-mentioned perovskite cell.

[0036] The beneficial effects of this invention include:

[0037] (1) In this invention, the hole transport layer material has a HOMO energy level difference that matches the perovskite material, resulting in less energy loss of holes from the perovskite layer to the hole transport layer, thus improving the open-circuit voltage of the perovskite solar cell. Reducing the HOMO energy level difference further reduces the energy loss of holes from the perovskite layer to the hole transport layer, which helps to improve the open-circuit voltage of the device;

[0038] (2) In this invention, the hole transport layer material has large π bonds, which is beneficial for enhancing hole transport capability, facilitating rapid hole transport to the electrodes, reducing the series resistance of the device, and improving the fill factor.

[0039] (3) In this invention, the hole transport layer material can be arranged in an ordered manner and self-assembled into a dense thin film to reduce defects;

[0040] (4) In this invention, the hole transport layer material utilizes the electron-rich groups of R1 and R4 to make the molecular fragments in which they are located a good "landing point" for holes. This promotes the hole transition process between molecules, thereby improving the overall hole mobility of the material.

[0041] (5) The present invention uses the setting of R1-R4 to passivate the uncoordinated lead ions (Pb²⁺) on the surface and grain boundaries of the perovskite film, while anchoring the substrate, thereby strengthening the connection between the perovskite film and the substrate and reducing the probability of Pb²⁺ being attacked by water, thus enhancing the long-term stability of the device. Attached Figure Description

[0042] Figure 1 A diagram showing the numbering of the substitution positions of the carbazole group;

[0043] Figure 2 The 1H NMR spectrum of the hole transport layer material obtained in Example 1;

[0044] Figure 3 Fourier transform infrared (FT-IR) spectra of the hole transport layer materials obtained in Examples 1 and 2;

[0045] Figure 4 The 1H NMR spectrum of the hole transport layer material obtained in Example 2;

[0046] Figure 5 SEM image of the perovskite thin film in Example 3;

[0047] Figure 6 SEM image of the perovskite film in Comparative Example 2;

[0048] Figure 7 Performance data of the batteries in Examples 1, 2, and 1 (Comparative Example 1);

[0049] Figure 8 Performance data of the batteries in Comparative Example 2 and Example 3. Detailed Implementation

[0050] 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.

[0051] "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.

[0052] This invention provides a novel compound, as shown in structural formula 1, which can be used as a hole transport layer material. For ease of understanding, this compound will be referred to as a hole transport layer material. This material utilizes diphenylbisthiophene and two carbazole groups to construct a conjugated system, which on the one hand enhances the electron delocalization ability and improves the charge conductivity, and on the other hand enhances the π-π stacking of the material to form a dense conductive layer, reduce defects, reduce film thickness, and thus improve conductivity.

[0053] Structural Formula 1 In the formula: (R1) n Let R1 represent n substituents, where 0 ≤ n ≤ 4; and (R2) represent n substituents. n This represents n substituents R2, where 0 ≤ n ≤ 3; (R3) n This represents n substituents R3, where 0 ≤ n ≤ 3; (R4) n This represents n substituents R4, where 0 ≤ n ≤ 4; (R1) n (R2) n (R3) n (R4) n The values ​​of n in the equation are set independently and can be the same or different. When (R1) n When n=0, the benzene ring has no substituent R1. When (R1) n When n=2, two H atoms in the benzene ring are substituted by R1, as in structural formula two. The positions of the two R1 atoms are not limited; they can be ortho, meta, or para. n When n=3, three H atoms in the benzene ring are substituted by R1, as in structural formula three. The positions of the three R1 atoms are not limited. When n≥2, multiple R1 atoms can be the same or different. Similarly, (R2) n (R3) n (R4) n The settings are as above.

[0054] Structural Form 2;

[0055] Structure 3;

[0056] One or more R1 and / or R4 are introduced onto the terminal groups of the conjugated system. R1 and R4 can be the same or different, and their positions can be symmetrical or asymmetrical. R1 and R4 are each independently selected from amino groups and their derivatives, hydroxyl groups and their derivatives, methoxy groups and their derivatives, mercapto groups and their derivatives, methylthio groups and their derivatives, thiophene groups and their derivatives, phosphate groups and their derivatives, carboxylic acid groups and their derivatives, sulfonic acid groups and their derivatives. The amino, hydroxyl, methoxy, mercapto, methylthio, thiophene, phosphate, carboxylic acid, and sulfonic acid groups mentioned above refer not only to the smallest unit of the group, but also to other organic molecules containing the smallest unit. For example, the phosphate group can be -PO3H2 or -R-PO3H2 (R is a hydrocarbon group, preferably alkyl-C). n H 2n+1 (1 < n ≤ 4), amino groups include -NH2, -R-NH2, -NH-R, and -N-R2, where R is a hydrocarbon group. The derivatives mentioned above are molecules obtained from the parent molecule through reactions such as substitution, addition, oxidation, and esterification, such as the derivatives of phosphoric acid -C n H 2n-1 Br-PO3H2.

[0057] R1 can be placed at any substituted position on the benzene ring. For ease of description, the substitution positions on the carbazole group are numbered as follows: Figure 1 As shown, positions 1, 2, 3 and 4 are arranged according to their distance from -NH-. When multiple positions are set with R1, the multiple R1s can be the same, partially the same or different from each other, as shown in the following settings: (1) R1 is set only at position 2 of the benzene ring; (2) R1 is set at both positions 1 and 2, with position 1 being amino and position 2 being dimethylamino; (3) R1 is set at both positions 1 and 2, with both positions 1 and 2 being amino.

[0058] R1 and R4 may be in the same position or different, symmetrical or asymmetrical. R1 and R4 being in the same position means that the substitution positions are exactly the same, such as (1) R1 and R4 are both substituted in position 1, (2) both are substituted in position 4, (3) both are substituted in position 1 and position 4. The situations in which R1 and R4 are in different positions include but are not limited to (1) R1 is in position 1 and R4 is in position 2, (2) R1 is in position 1 and position 4, and R4 is in position 1 and position 3.

[0059] The groups of R1 and R4 can be the same or different. The same group of R1 and R4 means that the group types are the same, such as (1) the structural formula contains 1 R1 and 1 R4, and R1 and R4 are both phosphate groups; (2) the structural formula contains 2 R1 and 2 R4, and R1 and R4 are both phosphate groups; the different groups of R1 and R4 mean that the types are different, such as (1) the structural formula contains 1 R1, where R1 is a phosphate group and contains 1 R4, where R4 is a sulfonic acid group; (2) the structural formula contains 2 R1, where both R1 are phosphate groups and contains 2 R4, where one R4 is a sulfonic acid group and the other is a phosphate group; (3) the structural formula contains 2 R1, where both R1 are phosphate groups and contains 2 R4, where one R4 is a sulfonic acid group and the other is a carboxylic acid group.

[0060] R2 and R3 are introduced onto another benzene ring of the carbazole group. R2 and R3 may be the same or different. R2 and R3 are each independently selected from alkyl groups and their derivatives, phosphate groups and their derivatives, carboxylic acid groups and their derivatives, sulfonic acid groups and their derivatives, and trimethoxysilylpropyl groups and their derivatives. When (R2) n Or (R3) n When n=0, it represents no substituent R2 or R3. Alkyl groups include straight-chain alkyl groups or branched alkyl groups. Phosphate groups, carboxylic acid groups, sulfonic acid groups, and trimethoxysilylpropyl groups not only refer to the smallest unit of the group, but also include other molecules containing the smallest unit. For example, the sulfonic acid group can be -SO3H, -R-SO3H, or -SO3-R, where R is a hydrocarbon group. R2 and R3 can be symmetrical or asymmetrical, preferably symmetrical. R2 can replace any one or more of the positions 5, 7, and 8 in the benzene ring. If there are multiple positions, they can be (1) positions 5 and 7; (2) positions 5, 7, and 8; (3) positions 7 and 8; (4) positions 5 and 8. When multiple positions are replaced by R2, each R2 can be the same or different. For example, if positions 7 and 8 are both replaced by R2, then the R2 at position 7 can be phosphoric acid, and the R2 at position 8 can be sulfonic acid. Similarly, R3 can replace one or more of its positions. When there are multiple positions, they can be the same or different.

[0061] The positions of R2 and R3 can be the same or different, such as (1) both R2 and R3 are at position 8; (2) R2 is at position 8 and R3 is at position 7; (3) R2 is at positions 7 and 8 and R3 is at position 7; the groups of R2 and R3 can be the same or different, such as (1) containing only 1 R2 and R2 is phosphoric acid, containing only 1 R3 and R3 is phosphoric acid; (2) containing only 1 R2 and R2 is phosphoric acid, containing only 1 R3 and R3 is methyl; (3) containing 2 R2, both of which are methyl, and containing 2 R3, one of which is methyl and the other is phosphoric acid.

[0062] As a preferred approach, (R2)n (R3) n In the case where n=0, (R1) n (R4) n When n=1, the structural formula is:

[0063] This design reduces the steric hindrance of the hole transport layer material, which is conducive to the formation of a regular and ordered molecular arrangement and thus to electron transport.

[0064] More preferably, R1 and / or R4 contain N or / and O or / and S, and N, O, and S contain lone pairs of electrons. The N or / and O or / and S containing lone pairs of electrons are directly connected to the benzene ring. More preferably, R1 and R4 are each independently selected from dimethylamino and methoxy. This design utilizes the electron-donating properties of dimethylamino groups to increase electron delocalization and enlarge the conjugated region, while simultaneously passivating lead-ion defects in the perovskite layer, thereby enhancing charge transport capability and reducing non-radiative recombination. The dimethylamino groups are used to tune the HOMO energy level, matching it to the perovskite energy level and enhancing carrier transport capability. The anchoring effect of phosphate groups on the substrate material enhances the connection between the hole transport material and the substrate. Simultaneously, the phosphate groups passivate lead-ion defects in the perovskite layer, reducing defects while connecting the perovskite layer. One of the R1 and R4 terminals anchors to the substrate, while the other connects to the perovskite layer, enabling a vertical molecular structure. This not only increases the ordered arrangement of molecules, facilitating a reduction in film thickness, but also matches the conjugated regions of the molecules to the carrier transport path, allowing carriers to transport along the shortest path at the fastest speed.

[0065] As a specific example, the hole transport layer material in this invention may be a combination of one or more of the following:

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] .

[0073] Further optimization of the cavity layer includes a combination of one or more of the following:

[0074]

[0075] .

[0076] In this invention, the hole transport layer material can be synthesized using raw material one, raw material two, and raw material three, where raw material one is... Raw material two is Raw material three is In the formula, X1 and X2 are the substituents eliminated during the synthesis of raw material one and raw material two, and X3 and X4 are the substituents eliminated during the synthesis of raw material two and raw material three. That is, raw material one and raw material two can undergo the following reaction:

[0077] ;

[0078] The reaction between reactant 3 and reactant 4 can occur as follows:

[0079] ;

[0080] As an alternative, X1, X2, X3, and X4 are selected from halogens and pinacol borate esters, such as X1 and X4 being -Br and X2 and X3 being pinacol borate esters, or X1 and X4 being pinacol borate esters and X2 and X3 being -Br.

[0081] The synthesis method specifically includes the following steps:

[0082] In an inert atmosphere, raw material one and raw material two undergo a coupling reaction with an organohalogen / pseudohalogenated product and an organoboron reagent at a certain temperature to yield intermediate one. Raw material one is... Raw material two is Intermediate one is ;

[0083] b. Raw material three and intermediate one undergo a coupling reaction to obtain intermediate two, wherein raw material three is... Intermediate two is ;

[0084] X1 is a halogen group, X2 is pinacol ester of borate, X3 is pinacol ester of borate, and X4 is a halogen group. The order of steps a and b can be interchanged. When raw material one and raw material three are the same, they can be combined into one step reaction. Steps a and b can be carried out in the same reaction system (such as raw material one and raw material three being the same) or in different reaction systems (raw material one and raw material three being different).

[0085] S02 converts material five into intermediate three under the action of 1-chloroethyl chloroformate. Intermediate three is...

[0086] ;

[0087] S03 eliminates HCl from intermediate tri under the action of methanol, converting it into the desired hole transport layer material.

[0088] As an example, when the hole transport layer material is of structure type two, the synthesis steps are as follows:

[0089] Structural Form 2 (1)

[0091] ;

[0092] (2) ;

[0093] (3)

[0094] When the hole transport layer material is structural formula three, the synthesis steps are as follows:

[0095] Structural Form Three

[0096]

[0097]

[0098] For more detailed preparation methods, please refer to the specific examples section.

[0099] Example 1

[0100] The structural formula of the hole transport layer material is:

[0101] .

[0102] The synthesis method of the material is as follows:

[0103]

[0104] The preparation method adopted is as follows:

[0105] 1. Prepare a three-necked round-bottom flask, clean it, and dry it overnight in an oven at 120°C. After cooling the flask, install the magnetic stirrer, condenser, and nitrogen / argon gas delivery line. Evacuate the entire system using an oil pump and purge with nitrogen three times to ensure an oxygen-free and water-free environment.

[0106] 2. Under nitrogen protection, add the following to the reaction flask in sequence: 2,8-di(pinacol borate)dibenzothiophene (1.0 mmol, 1.0 eq), 3-bromo-7-(dimethylamino)-9-ethylcarbazole (2.2 mmol, 2.2 eq), potassium phosphate (K3PO4) (6.0 mmol, 6.0 eq), SPhos (2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl) (0.04 eq, 4 mol%), toluene (20 mL), and deionized water (5 mL); at room temperature, stir the mixture rapidly while bubbling nitrogen or argon gas under the liquid surface for 20-30 minutes.

[0107] 3. Stop bubbling, and under nitrogen positive pressure protection, quickly add palladium(II) acetate [Pd(OAc)2] (0.02 eq, 2 mol%). Place the reaction flask in an oil bath preheated to 90-100℃, turn on the cooling water and stir vigorously. Reflux the reaction at this temperature for 12 hours. Monitor the reaction progress using thin-layer chromatography, using hexane:dichloromethane = 3:1 as the developing solvent. The reaction is considered complete when the starting material 3-bromo-7-(dimethylamino)-9-ethylcarbazole has essentially disappeared.

[0108] 4. Stop heating and cool the reaction solution to room temperature. Add 30 mL of deionized water and 50 mL of dichloromethane to the reaction mixture, allow it to stand and separate into layers, separate the lower organic phase, wash it successively with deionized water and saturated brine, dry the washed organic phase with anhydrous sodium sulfate, stir for 15 minutes and filter, remove the solvent under reduced pressure using a rotary evaporator to obtain a yellow solid crude product.

[0109] 5. The yellow crude product was dissolved in dichloromethane and then mixed with silica gel for purification to obtain a high-purity yellow solid.

[0110] Dissolve the yellow solid in a small amount of hot, good solvent (toluene), then slowly add a poor solvent (hexane) until the solution becomes slightly cloudy, and then allow it to stand and cool to crystallize.

[0111] 6. Prepare a dry reaction flask equipped with a magnetic stir bar and a condenser, and protect it with nitrogen or argon gas.

[0112] 7. Dissolve 658.91 mg of 2,8-bis(7-(dimethylamino)-9-ethylcarbazole-3-yl)dibenzothiophene (658.91 mg, 1.0 eq) obtained in step 5 in anhydrous dichloroethane (DCE). Add 357.425 mg of 1-chloroethyl chloroformate (ACE-Cl) to the solution. Add a slight excess of ACE-Cl (357.425 mg, 2.5 eq). Heat the reaction mixture to reflux and stir until the reaction is complete.

[0113] 8. After the reaction is complete, cool the reaction solution to room temperature. Use a rotary evaporator to evaporate the solvent dichloroethane (DCE) and excess ACE-Cl under reduced pressure. Add methanol to the resulting residue, heat the methanol solution to reflux, and stir thoroughly to obtain the target product. Spectroscopic analysis of the final product is shown below. Figure 2 and Figure 3 As shown, the synthesized product is the target product.

[0114] Inverted (pin) wide-bandgap perovskite (1.67 eV) solar cells were fabricated using the obtained hole transport layer material. The fabrication method is as follows:

[0115] S01 Obtain the substrate

[0116] 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.

[0117] S02 is used to prepare the hole transport layer.

[0118] (1) Mix 1 mg of 2-(7-dimethylamino-9H-carbazole-3-yl)-8-(2-dimethylamino-9H-carbazole-6-yl)dibenzothiophene with 1 mL of (methanol:DMSO=95:5) solution to obtain a 1 mg / mL solution of this material. Use a 0.45 μm filter to filter out large particles. The filtered solution is ready for use.

[0119] (2) Spin-coat the filtered solution onto ITO glass at a spin rate of 4000 rpm for 40 s;

[0120] (3) Anneal at 100℃ for 10 min to obtain a hole transport layer with a thickness of about 3 nm.

[0121] S03 for preparing perovskite films

[0122] (1) Preparation of perovskite film solution

[0123] Solution A is prepared by dissolving PbI₂ (lead iodide), FAI (formaldehyde iodide), PbBr₂ (lead bromide), and FABr (formaldehyde bromide) in a molar ratio of 0.75:0.75:0.25:0.25 in a mixture of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), where the volume ratio of DMF to DMSO is 5:1. Solution A contains Pb... 2+ The concentration was 1.7 mol / L;

[0124] b. Add MACl additive to solution one to form solution two, where the mass fraction of MACl in solution two is 20%.

[0125] c. Heat the solution to 70°C and stir for 70 minutes until completely dissolved;

[0126] The solution was filtered using a 0.22 μm filter cartridge to remove large particles and obtain a perovskite membrane solution.

[0127] (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.

[0128] (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.

[0129] S04 Preparation of Modification Layer

[0130] (1) Preparation of passivation layer: Dissolve 0.5 mg of EDAI (ethylenediamine dihydroiodide) in 1 mL of isopropanol, shake and stir to form an isopropanol solution of 0.5 mg / mL EDAI, and filter the solution with a 0.45 μm filter to remove larger particles and obtain PEAI solution.

[0131] (2) The EDAI solution was spin-coated onto the perovskite film at a speed of 2000 rpm for 30 s, and then annealed in a glove box at 100°C for 30 s to form an EDAI modified layer with a thickness of about 3 nm.

[0132] S05 is used to prepare the electron transport layer.

[0133] 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.

[0134] Preparation of S06 hole blocking layer:

[0135] Using vacuum evaporation equipment, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline or copper bath) material is evaporated by thermal evaporation to form an 8nm hole blocking layer on the electron transport layer. The evaporation vacuum degree is 7*10 -4 Below Pa.

[0136] Preparation of S07 electrode:

[0137] 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 Perovskite solar cells were fabricated at Pa below 1000 Pa.

[0138] Example 2

[0139] The hole transport layer material is:

[0140]

[0141] The synthesis method of the material is as follows:

[0142]

[0143]

[0144] The preparation method adopted is as follows:

[0145] 1. In an anhydrous and oxygen-free reaction flask, add 2,8-dibromodibenzothiophene (1.0 eq, 1 mol) and 9-ethyl-carbazole-3-boronate pinacol ester (0.85 eq, 0.85 mol). Then add potassium phosphate (K3PO4, 3.0 eq), palladium(II) acetate [Pd(OAc)2] (0.02 eq, 2 mol%), and SPhos (2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl) (0.04 eq, 4 mol%).

[0146] The mixture was evacuated / purged with nitrogen three times, then toluene and water (approximately 4:1 by volume) were added. The system was heated to 100°C and refluxed for 12 hours. After the reaction was complete, the mixture was cooled, the organic phase was extracted with ethyl acetate, washed with water and saturated brine, and dried over anhydrous sodium sulfate. Rotary evaporation yielded a mixture of the starting material, the target product, and the disubstituted byproduct.

[0147] 2. The mixture was separated by column chromatography with a hexane / dichloromethane gradient elution to obtain 2-bromo-8-(9-ethyl-carbazole-3-yl)dibenzothiophene.

[0148] 3. Under nitrogen protection, add 2-bromo-8-(9-ethylcarbazole-3-yl)dibenzothiophene (1.0 eq, 1 mol), 7-(dimethylamino)-9-ethylcarbazole-3-boronic acid pinacol ester (1.2 eq, 1.2 mol), K3PO4 (3.0 eq, 3 mol), Pd(OAc)2 (0.03 eq, 3 mol%), and SPhos (0.06 eq, 6 mol%) to a three-necked flask. Then add dioxane and water in a volume ratio of 5:1, totaling 20 ml, and bubble the mixture through nitrogen for 20 minutes.

[0149] 4. Heat the system to 95°C and stir vigorously until the reaction is complete.

[0150] 5. Cool the reaction solution, and extract, wash and dry to obtain 2-(7-(dimethylamino)-9-ethyl-9H-carbazole-3-yl)-8-(9-ethyl-9H-carbazole-3-yl)dibenzothiophene.

[0151] 6. Prepare a dry reaction flask equipped with a condenser and nitrogen protection. Dissolve 1 mol of the starting material 2-(7-(dimethylamino)-9-ethyl-9H-carbazol-3-yl)-8-(9-ethyl-9H-carbazol-3-yl)dibenzothiophene in anhydrous DCE. Add ACE-Cl (2.5 eq, 2.5 mol), and then heat the mixture to 80 °C under reflux for 2–4 hours. Monitor the disappearance of the starting material by TLC. After the reaction is complete, cool to room temperature. Use a rotary evaporator to completely remove the DCE and excess ACE-Cl, obtaining a dry residue.

[0152] 7. Add methanol to the dried residue, heat the system to reflux and stir for 1.5 hours to finally obtain the target molecule 2-(7-(dimethylamino)-9H-carbazole-3-yl)-8-(9H-carbazole-3-yl)dibenzothiophene.

[0153] The final products of spectral analysis, such as Figure 3 and Figure 4 As shown, the final product is the target product.

[0154] Perovskite solar cells were fabricated using the obtained hole transport layer material. The fabrication method of the cells is as follows:

[0155] S01 Obtain the substrate

[0156] 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.

[0157] S02 is used to prepare the hole transport layer.

[0158] (1) Mix 1 mg of 2-(7-(dimethylamino)-9H-carbazole-3-yl)-8-(9H-carbazole-3-yl)dibenzothiophene with 1 mL of (methanol:DMSO=95:5) solution to obtain a 1 mg / mL solution of this material. Use a 0.45 μm filter to filter out large particles. The filtered solution is ready for use.

[0159] (2) Spin-coat the filtered solution onto ITO glass at a spin rate of 4000 rpm for 40 s;

[0160] (3) Anneal at 100℃ for 10 min to obtain a hole transport layer with a thickness of about 3 nm.

[0161] S03 for preparing perovskite films

[0162] (1) Preparation of perovskite film solution

[0163] Solution A is prepared by dissolving PbI₂ (lead iodide), FAI (formaldehyde iodide), PbBr₂ (lead bromide), and FABr (formaldehyde bromide) in a molar ratio of 0.75:0.75:0.25:0.25 in a mixture of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), where the volume ratio of DMF to DMSO is 5:1. Solution A contains Pb... 2+ The concentration was 1.7 mol / L;

[0164] b. Add MACl additive to solution one to form solution two, where the mass fraction of MACl in solution two is 20%.

[0165] c. Heat the solution to 70°C and stir for 70 minutes until completely dissolved;

[0166] The solution was filtered using a 0.22 μm filter cartridge to remove large particles and obtain a perovskite membrane solution.

[0167] (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.

[0168] (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.

[0169] S04 Preparation of Modification Layer

[0170] (1) Preparation of passivation layer: Dissolve 0.5 mg of EDAI (ethylenediamine dihydroiodide) in 1 mL of isopropanol, shake and stir to form an isopropanol solution of 0.5 mg / mL EDAI, and filter the solution with a 0.45 μm filter to remove larger particles and obtain PEAI solution.

[0171] (2) The EDAI solution was spin-coated onto the perovskite film at a speed of 2000 rpm for 30 s, and then annealed in a glove box at 100°C for 30 s to form an EDAI modified layer with a thickness of about 3 nm.

[0172] S05 is used to prepare the electron transport layer.

[0173] 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.

[0174] Preparation of S06 hole blocking layer:

[0175] Using vacuum evaporation equipment, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline or copper bath) material is evaporated by thermal evaporation to form an 8nm hole blocking layer on the electron transport layer. The evaporation vacuum degree is 7*10 -4 Below Pa.

[0176] Preparation of S07 electrode:

[0177] 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 Perovskite solar cells were fabricated at Pa below 1000 Pa.

[0178] Example 3

[0179] The hole transport layer material is:

[0180]

[0181] Those skilled in the art can make adaptive adjustments to the preparation method in Example 1 to obtain the hole transport layer material.

[0182] A 1.67 eV silicon-calcium tandem perovskite solar cell with an inversion (pin) wide bandgap was fabricated using the obtained hole transport layer material. The fabrication method of the cell includes the following steps:

[0183] S01 Obtain the substrate

[0184] This sample uses a heterojunction silicon wafer as the silicon substrate. The silicon substrate information is as follows: Open-circuit voltage (V) oc ): 0.70~0.74 V, short-circuit current (J) sc ): 38~39.5 mA / cm 2 Fill factor (FF): 80~85%, photoelectric conversion efficiency (PCE): 24~25%. Silicon substrate size: 3 cm * 3 cm.

[0185] S02 is used to prepare the hole transport layer.

[0186] (1) Mix 1 mg of 2-(7-dimethylamino-9H-carbazole-3-yl)-8-(2-dimethylamino-9H-carbazole-6-yl)dibenzothiophene with 1 mL of (methanol:DMSO=95:5) solution to obtain a hole transport layer material solution of 1 mg / mL. Use a 0.45 μm filter to remove large particles. The filtered solution is ready for use.

[0187] (2) Spin-coat the filtered solution onto ITO glass at a spin rate of 4000 rpm for 40 s;

[0188] (3) Anneal at 100℃ for 10 min to obtain a hole transport layer with a thickness of about 3 nm.

[0189] S03 for preparing perovskite films

[0190] (1) Preparation of perovskite film solution

[0191] a. Dissolve 6.1 mg of CsI, 6.9 mg of MABr, 44.92 mg of PbBr2, 62.5 mg of FAI, and 118.68 mg of PbI2 in a mixture of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) to form 1 mL of solution 1, wherein the volume ratio of DMF to DMSO is 4:1;

[0192] b. Stir overnight at room temperature until completely dissolved;

[0193] c. Filter the solution using a 0.22 μm polytetrafluoroethylene filter head to remove large particles from the solution and obtain a perovskite membrane solution.

[0194] (2) Spin-coat the perovskite film solution onto the hole transport layer at spin-coating speeds of 1000 rpm / 20s / 200 rpm / s and 5000 rpm / 30s / 1000 rpm / s. At the 10th second of spin-coating, add 0.11 mL of the anti-solvent chlorobenzene to the film. After the addition is completed within 2 seconds, continue spin-coating for a total of 50 seconds.

[0195] (3) After spin coating, anneal in nitrogen at 100°C for 10 min, with humidity controlled at 20~30%, to obtain a perovskite film with a thickness of about 700 nm.

[0196] S04 Preparation of Modification Layer

[0197] (1) Preparation of passivation layer: Dissolve 0.5 mg of EDAI (ethylenediamine dihydroiodide) in 1 mL of isopropanol, shake and stir to form an isopropanol solution of 0.5 mg / mL EDAI, and filter the solution with a 0.45 μm filter to remove larger particles and obtain PEAI solution.

[0198] (2) The EDAI solution was spin-coated onto the perovskite film at a speed of 2000 rpm for 30 s, and then annealed in a glove box at 100 °C for 30 s to form an EDAI modified layer with a thickness of about 3 nm.

[0199] S05 is used to prepare the electron transport layer.

[0200] 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.

[0201] Preparation of S06 buffer layer:

[0202] SnO2 was prepared as a buffer layer with a thickness of 20 nm using an atomic layer deposition (ALD) apparatus.

[0203] Preparation of S07 transparent electrode

[0204] IZO material was prepared as a transparent electrode using magnetron sputtering on a buffer layer. The power was controlled between 30 W and 200 W, and the IZO thickness was 30 nm.

[0205] Preparation of S08 electrode

[0206] Using vacuum evaporation equipment, 400 nm silver (Ag) was deposited on the surface of the buffer layer as an electrode via thermal evaporation, and 300 nm silver (Ag) was deposited on the back of the battery as a back electrode. The evaporation vacuum degree was 7*10. -4 Below Pa.

[0207] Preparation of S09 antireflection layer:

[0208] A 90 nm thick antireflective layer of magnesium fluoride was deposited on the electrode surface using a vacuum evaporation equipment and a thermal evaporation method.

[0209] Example 4

[0210] The hole transport layer material is:

[0211]

[0212] A perovskite solar cell was fabricated using the hole transport layer material described above, following the same fabrication method as in Example 1. The short-circuit current of the resulting cell was 1.363 mA / cm². 2 The open-circuit voltage is 1.209 V, the fill factor is 82.45597%, and the highest efficiency point is 22.05454%.

[0213] Comparative Example 1

[0214] The only difference between the perovskite solar cell preparation method and Example 1 is that the hole transport layer material is Me-4PACz ((4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid).

[0215] Comparative Example 2

[0216] The only difference between the perovskite solar cell preparation method and Example 3 is that the hole transport layer material is Me-4PACz ((4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid).

[0217] Microscopic images of the perovskite layers obtained in Example 3 and Comparative Example 2 were observed under SEM, as follows: Figure 5 and Figure 6 As shown, in Example 3, there is less perovskite precipitation on the surface and the grain size is large, while in Comparative Example 2, the perovskite precipitation on the surface is much higher than in Example 3, and the grain size is small with more defects. This indicates that the hole transport layer material in this invention is beneficial to enhance the crystallization ability of perovskite and reduce perovskite grain boundary defects.

[0218] The photoelectric conversion efficiency of the batteries obtained in Example 1, Example 2, and Comparative Example 1 was tested under the same test conditions. Figure 7 As shown, a scanning method from high voltage (1.2 V) to low voltage (-0.1 V) was used, with a scan step size of 0.1 V and an interval of 20 ms. The conversion power of the battery was obtained by multiplying the voltage and current, and the conversion efficiency was obtained by combining the incident power of sunlight. The open-circuit voltage (Voc) of Example 1 was 1.24 V, which was significantly improved compared to 1.16 V of the comparative example, and the fill factor (FF) also increased from 76.3% to 83.5%. The open-circuit voltage (Voc) of Example 2 was 1.22 V, which was also significantly improved compared to 1.16 V of the comparative example. This demonstrates that the material has higher hole mobility and higher conductivity, which helps to quickly transport holes to the electrodes, reduce the series resistance of the device, and improve the fill factor. It can effectively passivate interface defects and suppress non-radiative recombination, thereby improving the open-circuit voltage and overall efficiency of the device.

[0219] The photoelectric conversion efficiency of the batteries obtained in Example 3 and Comparative Example 2 was tested under the same test conditions. Figure 8As shown, a test interval of 3000 ms, a current range of 0~0.05 A, a voltage range of 0~2.5 V, and a data volume of 100 were used. The conversion power of the battery was obtained by multiplying the voltage and current, and the conversion efficiency was obtained by combining the incident power of sunlight. The efficiency of Example 3 was 29.6%, which is a significant improvement compared to 25.5% of Comparative Example 2. The fill factor (FF) also increased from 72% to 78%, demonstrating that the material also plays a role in the stack-up, exhibiting higher hole mobility, higher conductivity, reduced series resistance of the device, improved conductivity, increased current density, and improved fill factor. It can effectively passivate interface defects and suppress non-radiative recombination, thereby improving the overall efficiency of the device.

[0220] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A compound, characterized in that: The structural formula is Structure I wherein: (R1) n represents n substituents R1, 0 < n < 4; (R2) n represents n substituents R2, 0 < n < 3; (R3) n represents n substituents R3, 0 < n < 3; (R4) n represents n substituents R4, 0 < n < 4; (R1) n , (R2) n , (R3) n , (R4) n n has the same or different values; R1, R4 are each independently selected from amino and its derivatives, hydroxyl and its derivatives, methoxy and its derivatives, sulfhydryl and its derivatives, methylthio and its derivatives, thienyl group and its derivatives, phosphoric acid group and its derivatives, carboxylic acid group and its derivatives, sulfonic acid group and its derivatives; R2, R3 are each independently selected from alkyl, phosphoric acid group and its derivatives, carboxylic acid group and its derivatives, sulfonic acid group and its derivatives, trimethoxysilylpropyl and its derivatives.

2. The compound of claim 1, wherein: (R1) n (R4) n wherein n = 1, (R2) n (R3) n wherein n = 0, the structural formula is Structural Formula Two.

3. The compound of claim 1 or 2, wherein: The R1, R4 satisfy one or a combination of the following two: The R1 contains N or / and O or / and S, the N, O, S contains a lone pair of electrons, the N or / and O or / and S containing a lone pair of electrons is directly connected with the benzene ring; The R4 contains N or / and O or / and S, the N, O, S contains a lone pair of electrons, the N or / and O or / and S containing a lone pair of electrons is directly connected with the benzene ring; R1 and R4 are both dimethylamino or both methoxy or both phosphoric acid groups.

4. The compound of claim 1, wherein: The structural formula is: 。 5. A process for the preparation of a compound according to claim 1, characterized by: obtained by coupling reaction of raw material 1 , raw material 2 , and raw material 3 , in which X1, X2are substituents eliminated during the synthesis of raw material 1 and raw material 2, X3, X4are substituents eliminated during the synthesis of raw material 2 and raw material 3, X1, X2, X3, X4are selected from halogen, boronic acid pinacol ester.

6. The method of claim 5, wherein: (R1) in structural formula one n (R2) n (R3) n (R4) n wherein n is 1, and the method comprises the steps of: S01 a raw material one and raw material two are placed in an inert atmosphere, under the action of a palladium catalyst and a base, organic halide or pseudohalide and organic boron reagent undergo coupling reaction to obtain intermediate one, intermediate one is ; X1 is a halogen group, and X2 is pinacol boronic acid ester; or X1 is pinacol boronic acid ester, and X2 is a halogen group; Intermediate 1 and starting material 3 are reacted in an inert atmosphere with a palladium catalyst and a mixed base to undergo a coupling reaction between the organohalogen or pseudohalogenated product and an organoboron reagent, yielding intermediate 2. Intermediate 2 is... ; X3 is a halogen group, and X4 is pinacol boronic acid ester; or X3 is pinacol boronic acid ester, and X4 is a halogen group; Steps a and b are carried out in the same reaction system or in different reaction systems; Intermediate two in S02 is converted to intermediate three under the action of 1-chloroethyl chloroformate ; The S03 intermediate three is converted into the required hole transport layer material under the action of methanol to eliminate HCl.

7. A hole transport layer material, characterized by: The compound comprises one or more compounds according to any one of claims 1-4.

8. A photovoltaic device, characterized by: The hole transport layer material comprises the hole transport layer material according to claim 7.

9. The photovoltaic device of claim 1, wherein: The preparation method of the hole transport layer comprises the following steps: dissolving the hole transport layer material in an organic solvent to obtain a hole transport layer solution, wherein the concentration of the hole transport layer material is 0.7-2.2 mg / mL, and the organic solvent is a mixed solvent of methanol and DMSO, and the volume mixing ratio of methanol to DMSO is (80:20)-(100:0).

10. A photovoltaic module, characterized by: The photovoltaic device comprises the photovoltaic device according to claim 8 or 9.

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