Composite hole transport layer, preparation method thereof and perovskite solar cell

Abstract

The invention relates to a composite hole transport layer, a preparation method thereof and a perovskite solar cell. The composite hole transport layer comprises a self-assembly monomolecular material and a thermal cross-linked polymer material; the preparation raw materials of the thermal cross-linked polymer material comprise a thermal cross-linked material; and the thermal crosslinking material comprises any one or a combination of at least two of MCz-VPOZ, TPDA or VB-FNPD. According to the preparation method, a stable polymer network framework is formed by thermal crosslinking of a thermal crosslinking material, a micromolecule self-assembled monomolecular material is embedded into a polymer network, the micromolecule self-assembled monomolecular material plays an orientation anchoring role, surface defects of a perovskite light absorption layer are efficiently passivated, and the perovskite light absorption layer is prepared. And meanwhile, a cross-linked polymer network formed by a thermal cross-linked material is used for fixing a micromolecule self-assembled monomolecular material, so that the mechanical strength of the hole transport layer is remarkably improved, and the thermal stability of the device is enhanced. Therefore, the obtained composite hole transport layer can achieve efficient passivation and lasting stability at the same time, and then the photoelectric performance of the perovskite solar cell is comprehensively optimized.

Description

Technical Field

[0001] This invention relates to the field of hole transport layer fabrication technology, and in particular to a composite hole transport layer, its fabrication method, and a perovskite solar cell. Background Technology

[0002] Currently, perovskite solar cells (PSCs) have become one of the core research directions of next-generation photovoltaic technology due to their excellent photoelectric conversion potential, low-cost advantages of solution-based fabrication, and adaptability to flexible devices. Among them, inverted perovskite solar cells (usually nip configuration) exhibit significantly improved stability at room temperature compared to traditional upright structures, providing a foundation for large-scale mass production and efficient integration of tandem cells.

[0003] In the exploration of performance improvement in inverted perovskite solar cells, the hole transport layer (HTL) plays a crucial role, making the selection of HTL materials equally critical. The successful application of carbazole-phosphonic acid self-assembled monolayers has significantly improved the performance of inverted perovskite solar cells, substantially boosting their power conversion efficiency (PCE). The phosphonic acid groups at one end of these small molecule materials can form strong chemisorption bonds with hydroxyl groups on the surface of a transparent conductive substrate or inorganic hole transport layer, enabling directional self-assembly of the molecules on the substrate surface to form an ordered monolayer. Meanwhile, the carbazole groups at the other end effectively reduce the hole extraction barrier. Furthermore, the phosphonic acid groups and nitrogen atoms in the carbazole-phosphonic acid self-assembled monolayers can bind to defect sites on the perovskite surface through coordination interactions, significantly reducing the defect state density and thus improving device efficiency.

[0004] However, the inherent defects of carbazole phosphonic acid self-assembled monolayer materials have become a key constraint on the long-term durability of inverted perovskite solar cells. During long-term device operation, especially at certain operating temperatures, their thermal stability is poor, making them prone to molecular rearrangement or desorption, which disrupts the integrity of the monolayer. Furthermore, from a film quality perspective, although the self-assembly process can achieve directional molecular alignment, the extremely thin monolayer structure is highly susceptible to factors such as uneven distribution of hydroxyl groups on the substrate surface and fluctuations in solvent evaporation rates, easily leading to uneven coverage of the substrate material and the formation of "defect channels." All of these factors contribute to the long-term durability of devices when used as hole transport layer materials.

[0005] Therefore, improving the poor thermal stability and uneven coverage of carbazole phosphonic acid self-assembled monomolecules in hole transport layers, and thus enhancing the long-term durability of the devices, is a pressing technical problem that needs to be solved. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a composite hole transport layer, its preparation method, and a perovskite solar cell. The composite hole transport layer of this invention comprises a self-assembled monomolecule material and a thermally crosslinked polymer material. The thermally crosslinked polymer material is prepared from any one or a combination of at least two of the following: 10-(4-(3,6-dimethoxy-9H-carbazole-9-yl)phenyl)-3,7-bis(4-vinylphenyl)-10H-phenoxazine (MCz-VPOZ), (4-{4-[bis(4-vinylphenyl)amino]phenyl}phenyl)[bis(4-vinylphenyl)]amine (TPDA), or 9,9-bis(4-((4-vinylphenyl)methoxy)phenyl)-N2,N7-di-1-naphthyl-N2,N7-diphenyl-9H-fluorene-2,7-diamine (VB-FNPD). By utilizing thermally cross-linked materials to form a stable polymer network framework, small-molecule self-assembled monomolecules are embedded within this network. These monomolecules act as orientation anchors, efficiently passivating surface defects in the perovskite light-absorbing layer, suppressing non-radiative recombination, and improving electron transport efficiency. Simultaneously, the cross-linked polymer network formed by the thermally cross-linked materials immobilizes the small-molecule self-assembled monomolecules, significantly enhancing the mechanical strength of the hole transport layer and strengthening the thermal stability of the device. Therefore, the resulting composite hole transport layer achieves both efficient passivation and long-term stability, thereby comprehensively optimizing the photoelectric performance of perovskite solar cells.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a composite hole transport layer, wherein the raw materials of the composite hole transport layer include self-assembled monomolecule materials and thermally cross-linked polymer materials.

[0009] The raw materials for preparing the thermally crosslinked polymer material include thermally crosslinked materials;

[0010] The thermal crosslinking material includes any one or a combination of at least two of the following: 10-(4-(3,6-dimethoxy-9H-carbazole-9-yl)phenyl)-3,7-bis(4-vinylphenyl)-10H-phenoxazine, (4-{4-[bis(4-vinylphenyl)amino]phenyl}phenyl)[bis(4-vinylphenyl)]amine, or 9,9-bis(4-((4-vinylphenyl)methoxy)phenyl)-N2,N7-di-1-naphthyl-N2,N7-diphenyl-9H-fluorene-2,7-diamine.

[0011] The composite hole transport layer of this invention comprises a self-assembled monomolecular material and a thermally cross-linked polymer material. The self-assembled monomolecular material can spontaneously assemble into an ordered monolayer on the substrate surface. Its orientation anchoring groups can specifically bind to defect sites on the lower surface of the perovskite light-absorbing layer, thereby effectively passivating surface defects, significantly suppressing non-radiative recombination during device operation, improving carrier transport efficiency, and thus enhancing the photoelectric performance of the perovskite solar cell. By combining it with the thermally cross-linked polymer material, the small-molecule self-assembled monomolecular material can be embedded in the three-dimensional network structure of the thermally cross-linked polymer material, thereby fixing the small-molecule self-assembled monomolecular material and effectively enhancing the overall mechanical strength of the hole transport layer as well as improving the structural durability and thermal stability of the device. Therefore, the resulting composite hole transport layer can simultaneously achieve efficient passivation and long-term stability, thus comprehensively optimizing the photoelectric performance of the perovskite solar cell.

[0012] Among them, MCz-VPOZ, TPDA and VB-FNPD thermal crosslinking materials are thermally initiated in situ crosslinking. The resulting thermally crosslinked polymer materials have advantages such as high mechanical strength and restricted free movement of molecular chains. When they work synergistically with self-assembled monomolecular materials, they can effectively anchor / fix the self-assembled monomolecular layer, enhance the overall mechanical strength of the hole transport layer, and significantly improve the thermal stability of the device.

[0013] As a preferred embodiment of the present invention, the self-assembled monomolecule material is embedded in the polymer network of the thermally crosslinked polymer material.

[0014] As a preferred embodiment of the present invention, the self-assembled monomolecule material includes carbazole phosphonic acid-based self-assembled monomolecule materials.

[0015] It should be noted that this invention does not impose specific requirements or limitations on the specific materials of carbazole-phosphonic acid self-assembled monomolecules. Any carbazole-phosphonic acid self-assembled monomolecule is applicable to this invention, and those skilled in the art can make adaptive selections and adjustments according to actual conditions. For example, it can be [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid (4PADCB) or (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz). Any one or a combination of at least two of the following: (4-(9H-carbazole-9-yl)butyl)phosphonic acid (4PACz), (4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz), (4-(3,6-dibromo-9H-carbazole-9-yl)butyl)phosphonic acid (Br-4PACz), or (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (MeO-2PACz).

[0016] As a preferred technical solution of the present invention, the thickness of the composite hole transport layer is 1nm-50nm, such as 1nm, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm or 50nm.

[0017] In a second aspect, the present invention also provides a method for preparing a composite hole transport layer according to the first aspect, the method comprising the following steps:

[0018] A composite hole transport layer coating liquid is obtained by mixing a self-assembled monomolecule material, a thermal crosslinking material and an organic solvent. The composite hole transport layer coating liquid is coated on the surface of a substrate and then annealed to obtain a composite hole transport layer.

[0019] The thermal crosslinking material includes any one or a combination of at least two of the following: 10-(4-(3,6-dimethoxy-9H-carbazole-9-yl)phenyl)-3,7-bis(4-vinylphenyl)-10H-phenoxazine, (4-{4-[bis(4-vinylphenyl)amino]phenyl}phenyl)[bis(4-vinylphenyl)]amine, or 9,9-bis(4-((4-vinylphenyl)methoxy)phenyl)-N2,N7-di-1-naphthyl-N2,N7-diphenyl-9H-fluorene-2,7-diamine.

[0020] As a preferred embodiment of the present invention, the mass concentration of the self-assembled monomolecule material in the composite hole transport layer coating solution is 0.1 mg / mL-0.8 mg / mL, for example, 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL, 0.5 mg / mL, 0.6 mg / mL, 0.7 mg / mL or 0.8 mg / mL.

[0021] In this invention, the mass concentration of the self-assembled monomolecule material is controlled at 0.1 mg / mL to 0.8 mg / mL to achieve uniform and complete coverage. If the mass concentration of the self-assembled monomolecule material is too low, it will lead to insufficient coverage and uneven distribution of the self-assembled monomolecule material; if the mass concentration of the self-assembled monomolecule material is too high, it will lead to excessive aggregation and accumulation of the self-assembled monomolecule material, thereby hindering hole transport.

[0022] As a preferred embodiment of the present invention, the mass concentration of the thermally crosslinked material in the composite hole transport layer coating liquid is 0.1 mg / mL-1.0 mg / mL, for example, 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL, 0.5 mg / mL, 0.6 mg / mL, 0.7 mg / mL, 0.8 mg / mL, 0.9 mg / mL or 1.0 mg / mL.

[0023] In this invention, the mass concentration of the thermally crosslinked material is controlled between 0.1 mg / mL and 1.0 mg / mL. This allows for the effective construction of the polymer network framework after thermal crosslinking, maintaining the mechanical strength of the layer structure and providing stable support and functional interfaces for the device. If the mass concentration of the thermally crosslinked material is too low, the resulting polymer network will be insufficient or discontinuous, failing to completely fix the self-assembled monomolecules. This can easily lead to interface instability and molecule migration, affecting the long-term stability of the device. Conversely, if the mass concentration of the thermally crosslinked material is too high, the crosslinked polymer network in the resulting composite hole transport layer will be too dense, hindering hole transport and negatively impacting the device's charge balance and performance.

[0024] As a preferred embodiment of the present invention, the organic solvent includes any one or a combination of at least two of N,N-dimethylformamide, dimethyl sulfoxide, ethanol, chlorobenzene, isopropanol, methanol, or chloroform.

[0025] Preferably, the substrate includes a transparent conductive layer.

[0026] Preferably, the transparent conductive layer includes an FTO transparent conductive layer or an ITO transparent conductive layer.

[0027] Preferably, the annealing temperature is 90℃-150℃, such as 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃ or 150℃.

[0028] This invention controls the annealing temperature to 90℃-150℃, which enables complete cross-linking of thermally cross-linked materials to form a stable network framework, while effectively preventing decomposition and damage to self-assembled monomolecules. If the annealing temperature is too high, it will cause the monolayer material or thermally cross-linked polymer to decompose; if the annealing temperature is too low, the cross-linking process of the polymer network will be incomplete, resulting in unreacted residues or a weak structure within the system, making it difficult to form a continuous and dense network framework, thus affecting the stability of the interface and the lifespan of the device.

[0029] Preferably, the annealing time is 1 min to 20 min, such as 1 min, 3 min, 5 min, 8 min, 10 min, 12 min, 15 min, 18 min, or 20 min.

[0030] It should be noted that the present invention does not impose specific requirements or special limitations on the coating method. Commonly used coating methods in the art are applicable to the present invention, such as spin coating or blade coating. The rotation speed and time of spin coating and the speed and time of blade coating are not subject to specific requirements or special limitations, as long as uniform coating can be achieved. Those skilled in the art can make adaptive selections and adjustments according to actual conditions.

[0031] It should be noted that the present invention does not impose specific requirements or special limitations on the mixing method and mixing conditions. Commonly used mixing methods and mixing conditions in the art are applicable to the present invention, as long as the raw materials can be mixed evenly. Those skilled in the art can make adaptive selections and adjustments according to actual conditions.

[0032] Thirdly, the present invention also provides a perovskite solar cell, the perovskite solar cell comprising a composite hole transport layer as described in the first aspect, or a composite hole transport layer prepared by the preparation method described in the second aspect.

[0033] As a preferred embodiment of the present invention, the perovskite solar cell comprises a transparent conductive layer, a composite hole transport layer, a perovskite light-absorbing layer, an electron transport layer, a hole blocking layer, and a metal electrode, which are stacked sequentially.

[0034] Preferably, a metal oxide hole transport layer is further included between the transparent conductive layer and the composite hole transport layer.

[0035] Preferably, a perovskite modification layer is further included between the perovskite light-absorbing layer and the electron transport layer.

[0036] Preferably, the perovskite light-absorbing layer has the general chemical formula ABX3, wherein A includes methylamine ions (MA). ＋ ), formamidinium ion (FA) ＋ ) or dimethylammonium ion (DMA) ＋ B includes any one or at least two of the following, where B includes lead ions (Pb). 2 ＋ X includes iodide ions (I － ), bromide ions (Br) － ), chloride ions (Cl) － ) or thiocyanate ion (SCN) － Any one or at least two of the following.

[0037] Preferably, the band gap of the perovskite light-absorbing layer is 1.50eV-1.60eV, such as 1.50eV, 1.52eV, 1.55eV, 1.58eV or 1.60eV.

[0038] It should be noted that the present invention does not impose specific requirements or special limitations on the material of the transparent conductive layer. Any material commonly used by those skilled in the art is applicable to the present invention, such as ITO or FTO.

[0039] It should be noted that the present invention does not impose specific requirements or limitations on the material of the electron transport layer. Those skilled in the art can make adaptive selections and adjustments according to actual conditions. For example, it can be C 60 Or C 60 Any one or at least two of the derivatives.

[0040] It should be noted that the material of the perovskite modification layer is not subject to specific requirements or special limitations in this invention. Those skilled in the art can make adaptive selections and adjustments according to actual conditions. For example, it can be any one or at least a combination of two of PEAI (phenylethylamine iodide), CBA (4-chlorobenzoic acid), and PDAI2 (1,3-propanediamine dihydroiodide).

[0041] It should be noted that the material of the hole-blocking layer is not specifically required or limited in this invention. Those skilled in the art can make adaptive selections and adjustments according to actual conditions, for example, it can be SnO. x And or BCP.

[0042] It should be noted that the present invention does not impose specific requirements or special limitations on the material of the metal electrode. Any material commonly used by those skilled in the art is applicable to the present invention, such as Ag, Au, or Cu.

[0043] It should be noted that the present invention does not impose specific requirements or special limitations on the preparation methods of the perovskite light-absorbing layer, electron transport layer and hole blocking layer. Any preparation method commonly used by those skilled in the art is applicable to the present invention. For example, it can be any one or at least a combination of two of the following methods: spin coating, slot coating, inkjet printing, vacuum thermal deposition, electron beam evaporation, magnetron sputtering or atomic layer deposition.

[0044] It should be noted that the present invention does not impose specific requirements or special limitations on the preparation method of the metal electrode. Any preparation method commonly used by those skilled in the art is applicable to the present invention. For example, it can be any one or at least a combination of two of the following: vapor deposition, reactive plasma deposition, physical vapor deposition, or atomic layer deposition.

[0045] It should be noted that the present invention does not impose specific requirements or special limitations on the thickness of the transparent conductive layer, the perovskite light-absorbing layer, the electron transport layer, the hole blocking layer, and the metal electrode. The thicknesses commonly used in the art are all suitable for the present invention. Those skilled in the art can make adaptive selections and adjustments according to actual conditions. For example, the thickness of the transparent conductive layer can be 100nm-800nm, the thickness of the perovskite light-absorbing layer can be 300nm-1200nm, the thickness of the electron transport layer can be 10nm-50nm, the thickness of the hole blocking layer can be 1nm-20nm, and the thickness of the metal electrode can be 50nm-200nm.

[0046] Compared with the prior art, the present invention has at least the following beneficial effects:

[0047] The composite hole transport layer of this invention comprises a self-assembled monomolecular material and a thermally crosslinked polymer material. The raw material for preparing the thermally crosslinked polymer material includes any one or a combination of at least two of the following: 10-(4-(3,6-dimethoxy-9H-carbazole-9-yl)phenyl)-3,7-bis(4-vinylphenyl)-10H-phenoxazine (MCz-VPOZ), (4-{4-[bis(4-vinylphenyl)amino]phenyl}phenyl)[bis(4-vinylphenyl)]amine (TPDA), or 9,9-bis(4-((4-vinylphenyl)methoxy)phenyl)-N2,N7-di-1-naphthyl-N2,N7-diphenyl-9H-fluorene-2,7-diamine (VB-FNPD). By utilizing thermally cross-linked materials to form a stable polymer network framework, small-molecule self-assembled monomolecules are embedded within this network. These monomolecules act as orientation anchors, efficiently passivating surface defects in the perovskite light-absorbing layer, suppressing non-radiative recombination, and improving electron transport efficiency. Simultaneously, the cross-linked polymer network formed by the thermally cross-linked materials immobilizes the small-molecule self-assembled monomolecules, significantly enhancing the mechanical strength of the hole transport layer and strengthening the thermal stability of the device. Therefore, the resulting composite hole transport layer achieves both efficient passivation and long-term stability, thereby comprehensively optimizing the photoelectric performance of perovskite solar cells. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the structure of the perovskite solar cell provided in Embodiment 1 of the present invention.

[0049] Among them, 1-FTO transparent conductive layer; 2-composite hole transport layer; 3-perovskite light-absorbing layer; 4-perovskite modification layer; 5-C 60 Electron transport layer; 6-SnO x Hole blocking layer; 7-Cu electrode.

[0050] Figure 2These are JV performance curves of the perovskite solar cells provided in Embodiments 1, 2, 3, 4, 5, 6, 7, 8, 9, Comparative Example 1, and Comparative Example 2 of the present invention.

[0051] Figure 3 This is a graph showing the stability tracking data of the perovskite solar cells provided in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, Comparative Example 1, and Comparative Example 2 of the present invention at 85% humidity and 85°C, in accordance with ISOS-D3. Detailed Implementation

[0052] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0053] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0054] Example 1

[0055] This embodiment provides a composite hole transport layer, which includes polymer materials of 4PADCB and MCz-VPOZ. 4PADCB is embedded in the polymer network of MCz-VPOZ polymer material, and the thickness of the composite hole transport layer is 5nm.

[0056] The structural formula of MCz-VPOZ is: CAS No. 2834093-04-6.

[0057] This embodiment provides a method for preparing the composite hole transport layer, the method comprising the following steps:

[0058] A composite hole transport layer coating solution was obtained by mixing 4PADCB, MCz-VPOZ and chlorobenzene, wherein the mass concentration of 4PADCB was 0.3 mg / mL and the mass concentration of MCz-VPOZ was 0.1 mg / mL.

[0059] The composite hole transport layer coating solution was spin-coated onto the FTO transparent conductive layer at a speed of 4000 rpm for 30 seconds, and then annealed at 150°C for 10 minutes to obtain the composite hole transport layer.

[0060] This embodiment provides a perovskite solar cell. Figure 1This diagram illustrates the structure of a perovskite solar cell provided in Embodiment 1 of the present invention. The perovskite solar cell includes, in sequence, an FTO transparent conductive layer 1, a composite hole transport layer 2, a perovskite light-absorbing layer 3, a perovskite modification layer 4, and a C… 60 Electron transport layer 5, SnO x Hole blocking layer 6 and Cu electrode 7.

[0061] The method for preparing the perovskite solar cell includes the following steps:

[0062] S1. Clean the commercially available FTO transparent conductive layer sequentially with cleaning agent, water and isopropanol, and then irradiate it in an ultraviolet ozone treatment machine for 20 minutes to remove organic residues on the surface, and obtain an FTO transparent conductive layer (thickness 600nm) for later use.

[0063] S2. A composite hole transport layer is prepared using the preparation method provided in Example 1.

[0064] S3, configured with 1.3M CS 0.1 FA 0.9 8 mL of PbI3 concentration perovskite precursor solution was prepared, and then 89 mg of MACl and 202 mg of PbI2 were added per mL. The solvents were DMF and NMP in a ratio of 5:1. The precursor solution was stirred at room temperature for 1 h and then filtered. The filtered precursor solution was injected into a syringe and slit-coated onto the surface of the composite hole transport layer. The stage running speed was 20 mm / s, the ink injection speed was 20 μL / s, and the gap between the substrate and the slit head was 100 μm. After coating, the film was flash-evaporated for 30 s, held under pressure for 30 s, and then annealed at 150 °C for 10 min to obtain a perovskite light-absorbing layer with a thickness of 700 nm.

[0065] S4. Spin-coating an isopropanol solution of PDAI2 (CAS:120675-53-8) at a concentration of 1.0 mg / mL yielded a perovskite modified layer with a thickness of 5 nm.

[0066] S5. Prepare C with a thickness of 25 nm using a thermal evaporation method. 60 Electron transport layer;

[0067] S6. SnO with a thickness of 15 nm was prepared using the ALD method. x Barrier layer;

[0068] S7. A Cu electrode with a thickness of 120 nm was prepared by thermal evaporation.

[0069] Example 2

[0070] This embodiment provides a composite hole transport layer, which includes polymer materials of 4PADCB and TPDA. The 4PADCB is embedded in the polymer network of the polymer material of TPDA, and the thickness of the composite hole transport layer is 10 nm.

[0071] The structural formula of TPDA is: .

[0072] This embodiment provides a method for preparing the composite hole transport layer, the method comprising the following steps:

[0073] A composite hole transport layer coating solution was obtained by mixing 4PADCB, TPDA and chlorobenzene, wherein the mass concentration of 4PADCB was 0.3 mg / mL and the mass concentration of TPDA was 0.12 mg / mL.

[0074] The composite hole transport layer coating solution was spin-coated onto the FTO transparent conductive layer at a speed of 4000 rpm for 30 seconds, and then annealed at 100°C for 10 minutes to obtain the composite hole transport layer.

[0075] This embodiment provides a perovskite solar cell, which has the same structure as that in Embodiment 1.

[0076] The difference between the preparation method of the perovskite solar cell described in Example 2 and that in Example 1 is that the composite hole transport layer is prepared using the preparation method provided in Example 2, while the other preparation methods and parameters remain the same as in Example 1.

[0077] Example 3

[0078] This embodiment provides a composite hole transport layer, which includes polymer materials of 4PADCB and VB-FNPD. 4PADCB is embedded in the polymer network of VB-FNPD polymer material, and the thickness of the composite hole transport layer is 5nm.

[0079] The structural formula of VB-FNPD is: CAS No. 1173170-48-3.

[0080] This embodiment provides a method for preparing the composite hole transport layer, the method comprising the following steps:

[0081] A composite hole transport layer coating solution was obtained by mixing 4PADCB, VB-FNPD and chlorobenzene, wherein the mass concentration of 4PADCB was 0.3 mg / mL and the mass concentration of VB-FNPD was 0.14 mg / mL.

[0082] The composite hole transport layer coating solution was spin-coated onto the FTO transparent conductive layer at a speed of 4000 rpm for 30 seconds, and then annealed at 150°C for 10 minutes to obtain the composite hole transport layer.

[0083] This embodiment provides a perovskite solar cell, which has the same structure as that in Embodiment 1.

[0084] The difference between the fabrication method of the perovskite solar cell described in Example 3 and that in Example 1 is that the composite hole transport layer is prepared using the fabrication method provided in Example 3, while the other fabrication methods and parameters remain the same as in Example 1.

[0085] Example 4

[0086] This embodiment provides a composite hole transport layer, the composition and parameters of which are consistent with those of Embodiment 1.

[0087] This embodiment provides a method for preparing the composite hole transport layer. The difference between this method and that of Example 1 is that the mass concentration of MCz-VPOZ is 2 mg / mL, while the rest of the preparation method and parameters remain the same as in Example 1.

[0088] This embodiment provides a perovskite solar cell, the structure of which is consistent with that of Embodiment 1.

[0089] The difference between the preparation method of the perovskite solar cell described in Example 4 and that in Example 1 is that the composite hole transport layer is prepared using the preparation method provided in Example 4, while the other preparation methods and parameters remain the same as in Example 1.

[0090] Example 5

[0091] This embodiment provides a composite hole transport layer, the composition and parameters of which are consistent with those of Embodiment 1.

[0092] This embodiment provides a method for preparing the composite hole transport layer. The difference between this method and that of Example 1 is that the mass concentration of MCz-VPOZ is 0.05 mg / mL, while the rest of the preparation method and parameters remain the same as in Example 1.

[0093] This embodiment provides a perovskite solar cell, the structure of which is consistent with that of Embodiment 1.

[0094] The difference between the fabrication method of the perovskite solar cell described in Example 5 and that in Example 1 is that the composite hole transport layer is prepared using the fabrication method provided in Example 5, while the other fabrication methods and parameters remain the same as in Example 1.

[0095] Example 6

[0096] This embodiment provides a composite hole transport layer, the composition and parameters of which are consistent with those of Embodiment 1.

[0097] This embodiment provides a method for preparing the composite hole transport layer. The difference between this method and that of Example 1 is that the mass concentration of 4PADCB is 1 mg / mL, while the rest of the preparation methods and parameters remain the same as in Example 1.

[0098] This embodiment provides a perovskite solar cell, the structure of which is consistent with that of Embodiment 1.

[0099] The difference between the fabrication method of the perovskite solar cell described in Example 6 and that in Example 1 is that the composite hole transport layer is prepared using the fabrication method provided in Example 6, while the other fabrication methods and parameters remain the same as in Example 1.

[0100] Example 7

[0101] This embodiment provides a composite hole transport layer, the composition and parameters of which are consistent with those of Embodiment 1.

[0102] This embodiment provides a method for preparing the composite hole transport layer. The difference between this method and that of Example 1 is that the mass concentration of 4PADCB is 0.05 mg / mL, while the rest of the preparation methods and parameters remain the same as in Example 1.

[0103] This embodiment provides a perovskite solar cell, the structure of which is consistent with that of Embodiment 1.

[0104] The difference between the fabrication method of the perovskite solar cell described in Example 7 and that in Example 1 is that the composite hole transport layer is prepared using the fabrication method provided in Example 7, while the other fabrication methods and parameters remain the same as in Example 1.

[0105] Example 8

[0106] This embodiment provides a composite hole transport layer, the composition and parameters of which are consistent with those of Embodiment 1.

[0107] This embodiment provides a method for preparing the composite hole transport layer. The difference between this method and that of Embodiment 1 is that the overall annealing temperature is 80°C, while the other preparation methods and parameters remain the same as those of Embodiment 1.

[0108] This embodiment provides a perovskite solar cell, the structure of which is consistent with that of Embodiment 1.

[0109] The difference between the fabrication method of the perovskite solar cell described in Example 8 and that in Example 1 is that the composite hole transport layer is prepared using the fabrication method provided in Example 8, while the other fabrication methods and parameters remain the same as in Example 1.

[0110] Example 9

[0111] This embodiment provides a composite hole transport layer, the composition and parameters of which are consistent with those of Embodiment 1.

[0112] This embodiment provides a method for preparing the composite hole transport layer. The difference between this method and that of Embodiment 1 is that the overall annealing temperature is 200°C, while the other preparation methods and parameters remain the same as those of Embodiment 1.

[0113] This embodiment provides a perovskite solar cell, the structure of which is consistent with that of Embodiment 1.

[0114] The difference between the fabrication method of the perovskite solar cell described in Example 9 and that in Example 1 is that the composite hole transport layer is prepared using the fabrication method provided in Example 9, while the other fabrication methods and parameters remain the same as in Example 1.

[0115] Comparative Example 1

[0116] This comparative example provides a hole transport layer. The difference between this hole transport layer and that of Example 1 is that 4PADCB is omitted, while the rest of the composition and parameters remain the same as those of Example 1.

[0117] This comparative example provides a method for preparing the hole transport layer, the method comprising the following steps:

[0118] A hole transport layer coating solution was obtained by mixing MCz-VPOZ and chlorobenzene, wherein the mass concentration of MCz-VPOZ was 1 mg / mL;

[0119] The hole transport layer coating solution was spin-coated onto the FTO transparent conductive layer at a speed of 4000 rpm for 30 seconds, and then annealed at 150°C for 10 minutes to obtain the hole transport layer.

[0120] This comparative example provides a perovskite solar cell, the structure of which is consistent with that of Example 1.

[0121] The difference between the fabrication method of the perovskite solar cell described in this Comparative Example 1 and Example 1 is that the hole transport layer is prepared using the fabrication method provided in Comparative Example 1, while the other fabrication methods and parameters remain the same as in Example 1.

[0122] Comparative Example 2

[0123] This comparative example provides a hole transport layer. The difference between the hole transport layer and Example 1 is that MCz-VPOZ is omitted, while the rest of the composition and parameters are the same as in Example 1.

[0124] This comparative example provides a method for preparing the hole transport layer, the method comprising the following steps:

[0125] A hole transport layer coating solution was obtained by mixing 4PADCB and anhydrous ethanol, wherein the mass concentration of 4PADCB was 0.4 mg / mL.

[0126] The hole transport layer coating solution was spin-coated onto the FTO transparent conductive layer at a speed of 4000 rpm for 30 seconds, and then annealed at 100°C for 10 minutes to obtain the hole transport layer.

[0127] This comparative example provides a perovskite solar cell, the structure of which is consistent with that of Example 1.

[0128] The difference between the fabrication method of the perovskite solar cell described in Example 2 and that in Example 1 is that the hole transport layer is prepared using the fabrication method provided in Comparative Example 2, while the other fabrication methods and parameters remain the same as in Example 1.

[0129] The perovskite solar cells provided in Examples 1-9 and Comparative Examples 1-2 were placed under a xenon lamp solar simulator (100 mW·cm²). -2 The battery short-circuit current density-voltage (JV) curve performance was tested, with a test area of ​​22.08 cm². 2 The results show the percentage reduction in the device's photoelectric conversion efficiency to its initial efficiency after 1400 hours, 85% humidity, and 85℃ (test conditions: ISOS-D3). The specific test results are shown in Table 1.

[0130] Table 1

[0131]

[0132] The test results show that:

[0133] (1) As can be seen from Examples 1-3, the composite hole transport layer of the present invention comprises a self-assembled monomolecule material and a thermally cross-linked polymer material. The thermally cross-linked polymer material is prepared from any one or a combination of at least two of MCz-VPOZ, TPDA, or VB-FNPD. By utilizing the stable polymer network framework formed after thermal cross-linking of the thermally cross-linked material, the small-molecule self-assembled monomolecule material is embedded in the polymer network. The small-molecule self-assembled monomolecule material plays an orientation anchoring role, efficiently passivating surface defects of the perovskite light-absorbing layer, suppressing non-radiative recombination, and improving electron transport efficiency. Simultaneously, the cross-linked polymer network formed by the thermally cross-linked material fixes the small-molecule self-assembled monomolecule material, significantly improving the mechanical strength of the hole transport layer and enhancing the thermal stability of the device. Therefore, the resulting composite hole transport layer can simultaneously achieve efficient passivation and long-term stability, thereby comprehensively optimizing the photoelectric performance and damp heat resistance of perovskite solar cells.

[0134] Specifically, with PCE between 20% and 23%, after 1400 hours of testing at 85% humidity and 85°C, the module efficiency decreased to more than 91% of the initial efficiency, meaning the degradation rate was less than 9%.

[0135] (2) As can be seen from Examples 1 and 4-5, by controlling the mass concentration of the thermally crosslinked material to 0.1 mg / mL-1.0 mg / mL, the present invention can effectively build the polymer network framework after thermal crosslinking, maintain the mechanical strength of the layer structure, provide stable support and functional interface for the device, and thus make the electrochemical performance of the perovskite solar cell better and the device degradation rate lower after damp heat test. However, when the mass concentration of the thermally crosslinked material is too high or too low, the PCE of the device can be maintained above 20%, but the efficiency degradation rate increases after 1400h, 85% humidity and 85℃ test, all of which are greater than 10%.

[0136] (3) As can be seen from Examples 1 and 6-7, by controlling the mass concentration of the self-assembled monomolecule material to 0.1 mg / mL-0.8 mg / mL, the present invention can achieve uniform and complete coverage of the self-assembled monomolecule material, thereby resulting in better electrochemical performance of the perovskite solar cell. However, when the mass concentration of the self-assembled monomolecule material is too high or too low, the efficiency degradation rate of the device increases after testing at 1400 h, 85% humidity, and 85℃, both exceeding 20%.

[0137] (4) As can be seen from Examples 1 and 8-9, the present invention controls the annealing temperature to 90℃-150℃, which can achieve complete cross-linking of thermal cross-linked materials to form a stable network framework. At the same time, it can effectively avoid decomposition damage to self-assembled single-molecule materials, resulting in better electrochemical performance of perovskite solar cells and lower device decay rate after damp heat test.

[0138] (5) As can be seen from Example 1 and Comparative Examples 1-2, when the thermal crosslinking material MCz-VPOZ is used alone (Comparative Example 1), the efficiency decay rate of the device increases to 11% and the PCE decreases to 21.38% after testing at 1400h, 85% humidity and 85℃. When the self-assembled monomolecule material 4PADCB is used alone (Comparative Example 2), the efficiency decay rate of the device increases to 25% and the PCE decreases to 21.65% after testing at 1400h, 85% humidity and 85℃. Neither of these results can achieve the effect of the two materials combined in Example 1.

[0139] Figure 2 The JV performance curves of the perovskite solar cells provided in Embodiments 1, 2, 3, 4, 5, 6, 7, 8, 9, Comparative Example 1, and Comparative Example 2 of the present invention are shown. Figure 3 The figures show the stability tracking data of the perovskite solar cells provided in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, Comparative Example 1 and Comparative Example 2 of the present invention at 85% humidity and 85°C according to ISOS-D3. As can be seen from the figures, the perovskite solar cells provided in Examples 1-3 of the present invention can balance photoelectric performance and damp heat resistance, and have better overall performance, while the damp heat resistance of Examples 4-9 and Comparative Examples 1-2 is relatively poor.

[0140] In summary, the composite hole transport layer of the present invention comprises a self-assembled monomolecular material and a thermally crosslinked polymer material. The raw material for preparing the thermally crosslinked polymer material includes any one or a combination of at least two of the following: 10-(4-(3,6-dimethoxy-9H-carbazole-9-yl)phenyl)-3,7-bis(4-vinylphenyl)-10H-phenoxazine (MCz-VPOZ), (4-{4-[bis(4-vinylphenyl)amino]phenyl}phenyl)[bis(4-vinylphenyl)]amine (TPDA), or 9,9-bis(4-((4-vinylphenyl)methoxy)phenyl)-N2,N7-di-1-naphthyl-N2,N7-diphenyl-9H-fluorene-2,7-diamine (VB-FNPD). By utilizing thermally cross-linked materials to form a stable polymer network framework, small-molecule self-assembled monomolecules are embedded within this network. These monomolecules act as orientation anchors, efficiently passivating surface defects in the perovskite light-absorbing layer, suppressing non-radiative recombination, and improving electron transport efficiency. Simultaneously, the cross-linked polymer network formed by the thermally cross-linked materials immobilizes the small-molecule self-assembled monomolecules, significantly enhancing the mechanical strength of the hole transport layer and strengthening the thermal stability of the device. Therefore, the resulting composite hole transport layer achieves both efficient passivation and long-term stability, thereby comprehensively optimizing the photoelectric performance of perovskite solar cells.

[0141] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A composite hole transport layer, characterized in that, The composite hole transport layer comprises a self-assembled monomolecule material and a thermally cross-linked polymer material; The raw materials for preparing the thermally crosslinked polymer material include thermally crosslinked materials; The thermal crosslinking material includes any one or a combination of at least two of the following: 10-(4-(3,6-dimethoxy-9H-carbazole-9-yl)phenyl)-3,7-bis(4-vinylphenyl)-10H-phenoxazine, (4-{4-[bis(4-vinylphenyl)amino]phenyl}phenyl)[bis(4-vinylphenyl)]amine, or 9,9-bis(4-((4-vinylphenyl)methoxy)phenyl)-N2,N7-di-1-naphthyl-N2,N7-diphenyl-9H-fluorene-2,7-diamine.

2. The composite hole transport layer according to claim 1, characterized in that, The self-assembled monomolecule material is embedded in the polymer network of the thermally crosslinked polymer material.

3. The composite hole transport layer according to claim 1 or 2, characterized in that, The self-assembled monomolecule materials include carbazole phosphonic acid-based self-assembled monomolecule materials.

4. The composite hole transport layer according to any one of claims 1-3, characterized in that, The thickness of the composite hole transport layer is 1nm-50nm.

5. A method for preparing a composite hole transport layer according to any one of claims 1-4, characterized in that, The preparation method includes the following steps: A composite hole transport layer coating liquid is obtained by mixing a self-assembled monomolecule material, a thermal crosslinking material and an organic solvent. The composite hole transport layer coating liquid is coated on the surface of a substrate and then annealed to obtain a composite hole transport layer. The thermal crosslinking material includes any one or a combination of at least two of the following: 10-(4-(3,6-dimethoxy-9H-carbazole-9-yl)phenyl)-3,7-bis(4-vinylphenyl)-10H-phenoxazine, (4-{4-[bis(4-vinylphenyl)amino]phenyl}phenyl)[bis(4-vinylphenyl)]amine, or 9,9-bis(4-((4-vinylphenyl)methoxy)phenyl)-N2,N7-di-1-naphthyl-N2,N7-diphenyl-9H-fluorene-2,7-diamine.

6. The preparation method according to claim 5, characterized in that, In the composite hole transport layer coating solution, the mass concentration of the self-assembled monomolecule material is 0.1 mg / mL to 0.8 mg / mL.

7. The preparation method according to claim 5 or 6, characterized in that, In the composite hole transport layer coating solution, the mass concentration of the thermal crosslinking material is 0.1 mg / mL to 1.0 mg / mL.

8. The preparation method according to any one of claims 5-7, characterized in that, The organic solvent includes any one or a combination of at least two of N,N-dimethylformamide, dimethyl sulfoxide, ethanol, chlorobenzene, isopropanol, methanol, or chloroform; Preferably, the substrate includes a transparent conductive layer; Preferably, the transparent conductive layer comprises an FTO transparent conductive layer or an ITO transparent conductive layer; Preferably, the annealing temperature is 90℃-150℃; Preferably, the annealing time is 1 min to 20 min.

9. A perovskite solar cell, characterized in that, The perovskite solar cell includes a composite hole transport layer as described in any one of claims 1-4, or a composite hole transport layer prepared by the preparation method described in any one of claims 5-8.

10. The perovskite solar cell according to claim 9, characterized in that, The perovskite solar cell comprises a transparent conductive layer, a composite hole transport layer, a perovskite light-absorbing layer, an electron transport layer, a hole blocking layer, and a metal electrode, which are stacked sequentially. Preferably, a perovskite modification layer is further included between the perovskite light-absorbing layer and the electron transport layer.

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