Thiazine derivative self-assembled monomolecular layer hole transport material and preparation method and application thereof

Abstract

The invention provides a thiazine derivative self-assembled monomolecular layer hole transport material and a preparation method and application thereof, and belongs to the technical field of solar energy industry. The self-assembled monomolecular layer hole transport material is simple in structure, high in hole transport property, strong in interface passivation ability, high in thermal stability and suitable for large-scale application, thiazine with a rigid conjugate large plane serves as a parent nucleus, molecular accumulation can be improved, and the hole transport performance of the material can be improved; by taking a phosphate group as a tail end, single-molecule self-assembly can be realized, a perovskite interface can be passivated, the energy loss at the interface is reduced, and the battery performance is improved. When the synthesized material is used as a hole transport layer of an inverted perovskite solar cell, gt can be obtained without doping; and meanwhile, the service life of the perovskite solar cell is greatly prolonged, the stability of the perovskite solar cell is greatly improved, and industrialization of the perovskite solar cell is expected to be achieved.

Description

Technical Field

[0001] This invention belongs to the field of solar energy technology, and relates to a thiazide derivative self-assembled monolayer hole transport material, its preparation method and application. Background Technology

[0002] As a next-generation photovoltaic technology, perovskite solar cells (PSCs) have advantages such as simple fabrication processes, easily modulated materials, and low cost. The latest certified efficiency has reached 26.2% (National Renewable Energy Laboratory, NREL, 2023). Perovskite solar cells have two main structural types: forward-biased nip structures and reverse-biased pin structures. Compared to nip structures, pin structures are more suitable for fabricating large-area, tandem solar cells because they can utilize low-temperature processes and a wider variety of carrier extraction layers, offering greater commercial potential. However, pin structures also face a challenge: improving the interface quality and stability between the hole-selective layer and the perovskite. Currently, commonly used hole transport materials (HTMs) for reverse-biased devices include inorganic materials like nickel oxide (NiOx) and organic polymers such as poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA). Among the challenges, nickel oxide and perovskite exhibit energy level mismatches and defect states, leading to voltage drops and interface degradation. PTAA (particulate-extruded aluminum oxide) suffers from high cost, batch instability, and low film wettability, all limiting further performance improvements. Therefore, developing high-performance, novel hole transport materials for inverted devices is crucial for device performance. Self-assembled monolayers (SAMs) offer advantages such as simple structure and flexible design, enabling effective tuning of interface energy levels and reduction of defect states through molecular engineering. Furthermore, these materials exhibit unique advantages including low parasitic absorption, low material consumption, compatibility with tandem perovskite solar cells, and simplified large-area device fabrication, making them a popular choice for high-efficiency perovskite solar cells. Therefore, developing novel SAM materials with simple structure, low cost, and excellent performance is a key issue that urgently needs to be addressed to promote the industrialization of perovskite solar cells (PSCs).

[0003] Hole transport materials (HTMs) are an important component of battery cell (PSC) and play a crucial role in the efficiency and stability of the battery. Poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) is currently the most commonly used HTM in high-efficiency inverted PSCs, but several problems with PTAA itself seriously hinder the industrialization of inverted PSCs: First, the price of PTAA is as high as $1980 / g, dozens of times that of gold, preventing its large-scale application; second, PTAA itself has a low hole mobility (approximately 10). 5 cm 2 V -1 s -1 To improve hole transport performance, dopants such as lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) and 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone (F4TCNQ) need to be added. However, these water-absorbing dopants can cause the decomposition of perovskite, which greatly affects the long-term stability of the battery. Finally, as a polymer, PTAA's molecular weight and photovoltaic performance can change with each synthesis batch, which is not conducive to industrial application.

[0004] Therefore, developing new SAM materials with simple structure, low cost, and excellent performance is a key issue that urgently needs to be addressed to promote the industrialization of PSCs. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a thiazide derivative self-assembled monolayer hole transport material, its preparation method, and its applications. The self-assembled monolayer hole transport material of the present invention is an undoped hole transport material, which uses a carbazole derivative as the parent core and butyl phosphate as the anchoring group. It exhibits a simple structure, high hole transport capacity, strong interface passivation ability, and high thermal stability.

[0006] To achieve this objective, the present invention employs the following technical solution:

[0007] On one hand, the present invention provides a thiazide derivative self-assembled monolayer hole transport material, wherein the thiazide derivative self-assembled monolayer hole transport material has the structure shown in Formula I:

[0008] .

[0009] The self-assembled monolayer hole transport material of this invention uses a thiazide core with a rigid conjugated large plane as the parent core, which can improve molecular packing and enhance the hole transport performance of the material. With phosphate groups as terminals, it can achieve single-molecule self-assembly and passivate the perovskite interface, reducing energy loss at the interface and improving battery performance. When the synthesized material is used as the hole transport layer of an inverted perovskite solar cell, a photoelectric conversion efficiency of >24% can be obtained without doping, while significantly improving the lifetime and stability of the perovskite solar cell, which is expected to help industrialize perovskite solar cells.

[0010] On the other hand, the present invention provides a method for preparing the thiazide derivative self-assembled monolayer hole transport material as described above, the method comprising the following steps:

[0011] (1) The compound of formula II reacts with the compound of formula III to give the compound of formula IV, and the reaction formula is as follows:

[0012] ;

[0013] (2) The compound shown in Formula IV undergoes a hydrolysis reaction to obtain the self-assembled monolayer hole transport material based on the polycarbazole derivative shown in Formula I. The reaction formula is as follows:

[0014] ;

[0015] R1 and R2 are independently selected from C1-C5 alkyl groups, and X is selected from halogens.

[0016] In this invention, R1 and R2 are independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, etc., preferably ethyl. X is selected from F, Cl, Br or I, preferably Br.

[0017] Preferably, the molar ratio of the compound of formula II to the compound of formula III in step (1) is 1:1-1.5, for example 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4 or 1:1.5.

[0018] Preferably, the reaction in step (1) is carried out in the presence of a catalyst selected from cuprous iodide.

[0019] Preferably, the reaction in step (1) is carried out in the presence of an alkaline substance selected from potassium carbonate and / or sodium carbonate.

[0020] Preferably, the reaction in step (1) is carried out in an organic solvent selected from N,N'-dimethylacetamide.

[0021] Preferably, the reaction temperature in step (1) is 160~180℃ (e.g., 160℃, 162℃, 164℃, 166℃, 168℃, 170℃, 172℃, 174℃, 176℃ or 180℃, etc.), and the reaction time is 20~24 h (e.g., 20h, 21h, 22h, 23h or 24h, etc.).

[0022] Preferably, the hydrolysis reaction in step (2) is carried out in the presence of trimethylbromosilane.

[0023] Preferably, the molar ratio of the trimethylbromosilane to the compound shown in Formula IV is 2:1 to 4:1 (e.g., 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3:1, 3.2:1, 3.4:1, 3.6:1 or 4:1, etc.).

[0024] Preferably, the hydrolysis reaction in step (2) is carried out in an organic solvent, which is selected from dichloromethane and trichloromethane.

[0025] Preferably, the hydrolysis reaction in step (2) is carried out at room temperature for a reaction time of 12 to 18 hours (e.g., 12 hours, 13.5 hours, 15 hours, 16.5 hours or 18 hours).

[0026] On the other hand, the present invention provides a perovskite solar cell comprising a self-assembled monolayer, wherein the self-assembled monolayer comprises a hole transport material based on a polycarbazole derivative as described above.

[0027] Preferably, the perovskite solar cell is an inverted perovskite solar cell.

[0028] Preferably, the perovskite solar cell comprises, from top to bottom, a cathode layer, an electron transport layer, a passivation layer, a perovskite light-absorbing layer, a self-assembled monolayer, a hole transport layer, and an anode layer arranged sequentially.

[0029] Preferably, the self-assembled monolayer is obtained by coating a solution of the self-assembled monolayer hole transport material based on the polycarbazole derivative as described above onto the surface of the hole transport layer and then performing thermal annealing.

[0030] Preferably, the temperature of the heat annealing is 80~120℃ (e.g., 80℃, 90℃, 100℃, 110℃ or 120℃, etc.), and the heat annealing time is 5~20 minutes (e.g., 5 minutes, 8 minutes, 10 minutes, 13 minutes, 15 minutes, 18 minutes or 20 minutes, etc.).

[0031] In this invention, the perovskite light-absorbing layer is prepared by coating (e.g., spin-coating) a perovskite solution onto the surface of a self-assembled monolayer.

[0032] In this invention, the coating method can be slot coating or spin coating.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The self-assembled monolayer hole transport material of this invention features a simple structure, high hole transport capacity, strong interface passivation ability, and high thermal stability, making it suitable for large-scale applications. Using a thiazide core with a rigid, conjugated large planar surface as the parent core improves molecular packing and enhances the material's hole transport performance. Phosphate groups at the ends enable single-molecule self-assembly and passivation of the perovskite interface, reducing energy loss at the interface and improving battery performance. When the synthesized material is used as the hole transport layer in an inverted perovskite solar cell, a photoelectric conversion efficiency of >24% can be achieved without doping, while significantly improving the lifetime and stability of the perovskite solar cell, potentially facilitating the industrialization of perovskite solar cells. Attached Figure Description

[0035] Figure 1 The 1H NMR spectrum of intermediate 1;

[0036] Figure 2 The 1H NMR spectrum of compound A1;

[0037] Figure 3 IV curves for solar cells fabricated using compound A1 as a hole transport material;

[0038] Figure 4 This is a schematic diagram of a perovskite solar cell. Detailed Implementation

[0039] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0040] Example 1

[0041] Synthesis of compound A1

[0042]

[0043] Step 1: Synthesis of Intermediate 1

[0044] Under a nitrogen atmosphere, starting material 1 (1.58 g, 3.0 mmol) and starting material 2 (0.91 g, 3.1 mmol) were dissolved in 25 mL of N,N'-dimethylacetamide, followed by the addition of K₂CO₃ (0.83 g, 6.0 mmol) and cuprous iodide (0.06 g, 6.0 mmol). The reaction mixture was reacted at 180 °C for 24 h. After the reaction was complete, the mixture was cooled to room temperature. It was diluted with water and then extracted with dichloromethane. The organic layer was dried over anhydrous magnesium sulfate, filtered, and evaporated to dryness. The crude product was separated by silica gel column chromatography to give a white solid (0.78 g, 52%).

[0045] The 1H NMR spectrum of intermediate 1 is as follows Figure 1 As shown, 1 H NMR (400 MHz, DMSO-d6) δ 9.03-8.94 (m,1H), 8.43-8.36 (m, 1H), 8.16-8.10 (m, 1H), 8.07 (s, 1H), 7.67-7.59 (m, 2H),7.58-7.47 (m, 3H), 7.47-7.35 (m, 4H), 7.35-7.27 (m, 5H), 7.26 (s, 1H), 7.18(dd, J = 5.5, 3.2 Hz, 1H), 4.05-3.87 (m, 6H), 1.92 (dtd, J = 11.8, 9.2, 0.7Hz, 2H), 1.74-1.56 (m, 4H), 1.30 (td, J = 7.2, 0.7 Hz, 6H).

[0046] Step 2: Synthesis of compound A1

[0047] In a 50 mL dried round-bottom flask, intermediate 1 (0.36 g, 0.5 mmol) was dissolved in 20 mL of dichloromethane. Trimethylbromosilane (0.612 g, 0.528 mL, 4 mmol) was added dropwise to the well-stirred mixture at room temperature. After 12 hours, the mixture was carefully transferred to a 100 mL round-bottom flask and concentrated under reduced pressure. A magnetic stir bar and 20 mL of methanol were then added sequentially. The mixture was stirred at room temperature for 4 hours, filtered, washed with methanol (3 × 5 mL), and the combined filtrate was concentrated under reduced pressure to give a solid as the crude product. Recrystallization from methanol / dichloromethane / diethyl ether gave a white solid (0.26 g, 72%).

[0048] The 1H NMR spectrum of compound A1 is as follows Figure 2 As shown, 1H NMR (400 MHz, DMSO-d6) δ 9.03-8.94 (m,1H), 8.43-8.36 (m, 1H), 8.34 (s, 2H), 8.16-8.10 (m, 1H), 8.07 (s, 1H), 7.67-7.59 (m, 2H), 7.58-7.48 (m, 3H), 7.48-7.40 (m, 2H), 7.40-7.24 (m, 8H), 7.18(dd, J = 5.5, 3.1 Hz, 1H), 3.90 (s, 2H), 1.93-1.79 (m, 2H), 1.75-1.62 (m,4H).

[0049] Example 2

[0050] Perovskite solar cells were fabricated using the self-assembled monolayer material A1, and their structure is as follows: Figure 4 As shown, its structure is: Glass / FTO / NiOx / SAM / PVSK / C60 / SnO2 / Ag. The specific device fabrication process is as follows: First, the FTO conductive glass substrate is pretreated. The FTO glass is ultrasonically cleaned in detergent, deionized water, ethanol, and acetone for 15 minutes each, and then dried in a 75℃ oven. Before use, the glass needs to be treated with ultraviolet ozone for 10 minutes, and then a NiOx layer is prepared in air by spin coating. A 5 mg / mL NiOx aqueous solution is filtered through a 0.22 μm PTFE filter and dropped onto the surface of the FTO substrate. It is then rotated at 5000 rpm for 30 s on a spin coater, followed by thermal annealing at 120℃ for 15 minutes. The substrate after NiOx preparation is transferred to a nitrogen glove box to continue the preparation of self-assembled monolayers (SAM). 110 μL of a 0.35 mg / mL A1 ethanol solution was dropped onto the center of the substrate, and the mixture was spin-coated at 5000 rpm for 30 s, followed by thermal annealing at 100 °C for 10 min. The perovskite layer was deposited using a two-step spin-coating method, with 110 μL of the perovskite precursor solution (FA) being applied. 0.9 MA 0.05 Cs. 0.05A 1.5M PbI3 (DMF:DMSO volume ratio = 4:1) solution was dropped onto the center of the substrate. The first spin coating was performed at 2000 rpm for 20 seconds, followed by a second spin coating at 4500 rpm for 35 seconds. Ten seconds before the end of the second spin coating step, 110 μL of anisole was added uniformly to the center of the substrate, followed by thermal annealing at 110 °C for 20 minutes. After the perovskite film annealing was complete and the temperature cooled to room temperature, a passivation layer was prepared. 110 μL of PDADI2 (1,3-diaminopropane dihydroiodide dissolved in isopropanol (IPA), concentration 0.5 mg / mL) solution was dropped onto the center of the substrate, and the mixture was spin-coated at 5000 rpm for 30 seconds, followed by thermal annealing at 100 °C for 5 minutes. After annealing, the battery is transferred to a vapor deposition system, where a 21 nm thick C60 layer is deposited on the perovskite layer using vacuum thermal evaporation. Subsequently, a 25 nm thick SnO2 layer is deposited at 90 °C using atomic layer deposition (ALD). Finally, after scraping off excess film at the common end, a 100 nm thick Ag electrode is deposited by vacuum evaporation under masked conditions.

[0051] Based on the A1 obtained in Example 1, perovskite solar cell devices were fabricated and characterized according to the above procedure. The current-voltage (J-V) characteristic curves of the cell device performance are shown below. Figure 3 The open-circuit voltage Voc is 1.165V, and the short-circuit current density Jsc is 25.20mA / cm². 2 The fill factor FF is 0.845 and the photoelectric conversion efficiency is 24.81%.

[0052] Comparative Example 1

[0053] The self-assembled monolayer material A1 in Example 2 was replaced with [4-(10H-phenthiazin-10-yl)butyl]phosphoric acid (4PAPT), and its structure is as follows:

[0054]

[0055] The battery fabricated therein has an open-circuit voltage (Voc) of 1.10V and a short-circuit current density (Jsc) of 26.1 mA / cm². 2 The fill factor FF is 0.795 and the photoelectric conversion efficiency is 22.8%.

[0056] Comparative Example 2

[0057] The self-assembled monolayer material A1 in Example 2 is replaced with the following material, the structure of which is as follows:

[0058]

[0059] The battery fabricated therein has an open-circuit voltage (Voc) of 1.08V and a short-circuit current density (Jsc) of 25.4mA / cm².2 The fill factor FF is 0.734 and the photoelectric conversion efficiency is 20.8%.

[0060] Table 1 shows the parameters of inverted perovskite solar cells.

[0061] Table 1

[0062]

[0063] As shown in Table 1, the photoelectric conversion efficiency of the self-assembled single-molecule hole transport material of the rigid conjugated large planar thiazide system prepared in this invention is higher than that of Comparative Example 1 and Comparative Example 2. Due to the better matching of the A1 energy level with the perovskite, its voltage and fill factor are significantly improved, and a photoelectric conversion efficiency of up to 24.81% is obtained.

[0064] The applicant declares that this invention illustrates the thiazide derivative self-assembled monolayer hole transport material, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials used, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A thiazine derivative self-assembled monolayer hole transport material, characterized in that, The thiazine derivative self-assembled monolayer hole transport material has the following structure shown in formula I: 。 2. The method of claim 1, wherein the thiazine derivative self-assembled monolayer hole transport material is prepared by the following steps of: (a) preparing a solution of the thiazine derivative in a solvent; (b) immersing a substrate in the solution; (c) drying the substrate; and (d) removing the substrate from the solution. The preparation method comprises the following steps: (1) reacting a compound of formula II with a compound of formula III to obtain a compound of formula IV, as shown in the following reaction formula: ； (2) performing a hydrolysis reaction on the compound of formula IV to obtain the self-assembled monolayer hole transport material based on the polycarbazole derivative of formula I, as shown in the following reaction formula: ； wherein R1 and R2 are independently selected from C1-C5 alkyl, and X is selected from halogen.

3. The production method according to claim 2, characterized by, R1 and R2 are independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or n-pentyl; X is selected from F, Cl, Br or I.

4. The production method according to claim 2, characterized by, The molar ratio of the compound of formula II to the compound of formula III in step (1) is 1:1-1.

5.

5. The preparation method according to claim 2, characterized in that, The reaction in step (1) is performed in the presence of a catalyst, and the catalyst is cuprous iodide.

6. The preparation method according to claim 2, characterized in that, The reaction in step (1) is performed in the presence of a basic substance, and the basic substance is selected from potassium carbonate and / or sodium carbonate.

7. The preparation method according to claim 2, characterized in that, The reaction in step (1) is performed in an organic solvent, and the organic solvent is selected from N,N'-dimethylacetamide; The temperature of the reaction in step (1) is 160-180°C, and the reaction time is 20-24 h.

8. The preparation method according to claim 2, characterized in that, The hydrolysis reaction in step (2) is performed in the presence of trimethylsilyl bromide; The molar ratio of the trimethylsilyl bromide to the compound of formula IV is 2:1-4:1; The hydrolysis reaction in step (2) is performed in an organic solvent, and the organic solvent is selected from dichloromethane and / or trichloromethane; The hydrolysis reaction in step (2) is performed at room temperature, and the reaction time is 12-18 hours.

9. A perovskite solar cell, characterized by, The perovskite solar cell comprises a self-assembled monolayer, and the self-assembled monolayer comprises the thiazine derivative self-assembled monolayer hole transport material according to claim 1.

10. The perovskite solar cell according to claim 9, characterized in that, The perovskite solar cell is a transverse perovskite solar cell, and comprises, from top to bottom, a cathode layer, an electron transport layer, a passivation layer, a perovskite light absorption layer, a self-assembled monolayer, a hole transport layer and an anode layer arranged in sequence; The self-assembled monolayer is obtained by coating a solution of the thiazine derivative self-assembled monolayer hole transport material according to claim 1 onto the surface of the hole transport layer and performing thermal annealing; The temperature of the thermal annealing is 80-120°C, and the time of the thermal annealing is 5-20 minutes.

Images