Polymer hole transport material and perovskite solar cell

Abstract

The application provides a polymer hole transport material and a perovskite solar cell, the polymer hole transport material has a structure shown in general formula (I), the polymer hole transport material is a carboxyl functionalized pyrrolopyrrolodione conjugated polymer, overcomes the short board that a small molecule SAM material is sensitive to thickness, easy to aggregate and easy to fall off, realizes double core functions of hole transport and interface defect passivation, and the polymer hole transport material is applied to a trans perovskite solar cell device, so that a photoelectric conversion efficiency of > 14% is obtained and good stability is obtained.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell technology, and relates to a polymer hole transport material and a perovskite solar cell. Background Technology

[0002] Perovskite solar cells have become a research hotspot for next-generation photovoltaic technology due to their low fabrication cost and high photoelectric conversion efficiency. Hole transport materials, as one of the core components of perovskite solar cells, play a crucial role in hole extraction, transport, and blocking electron recombination; their performance directly determines the device efficiency and long-term stability. Polytriarylamine (PTAA) is a widely used hole transport material in inverted perovskite solar devices, but its hydrophobicity makes large-area, conformal coating of perovskite films difficult.

[0003] In recent years, self-assembled monolayers (SAMs) of small molecules have become hole transport materials for high-performance inverted perovskite solar cells, offering advantages such as low dosage, tunable energy levels, and low interfacial losses. In-depth research into the configuration of small-molecule SAMs has revealed that these materials tend to self-aggregate, resulting in uneven distribution on the substrate and exposing interfacial defects and voids. Furthermore, their weak bonding with the substrate makes them prone to molecular desorption and diffusion into the perovskite bulk phase under long-term operating conditions. This inherent instability and potential bulk diffusion problem severely compromises the long-term reliability of the device and limits the practical application of small-molecule SAM layers in the scalable fabrication of perovskite solar devices. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a polymer hole transport material and a perovskite solar cell. The polymer hole transport material of the present invention is a carboxyl-functionalized pyrrolopyrrole dione conjugated polymer, overcoming the shortcomings of small-molecule SAM materials such as thickness sensitivity, easy aggregation, and easy detachment. It achieves the dual core functions of hole transport and interface passivation, resulting in perovskite solar cell devices with high photoelectric conversion efficiency and good stability.

[0005] To achieve this objective, the present invention adopts the following technical solution: On one hand, the present invention provides a polymer hole transport material having the structure shown in general formula (I): ; Wherein, A is selected from C2-C20 alkylene or C6-C20 arylene; R is selected from phosphate group or carboxylic acid group; X is selected from C6-C20 aryl or C3-C20 heteroaryl; The degree of aggregation n is an integer from 2 to 100 (e.g., 2, 3, 5, 8, 10, 12, 14, 16, 18, 20, 24, 28, 30, 32, 34, 36, 38, 40, 44, 48, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100, etc.), preferably an integer from 3 to 20.

[0006] In this invention, C2-C20 can be C2, C3, C4, C5, C6, C8, C10, C12, C14, C16, C18 or C20, etc.; C6-C20 can be C6, C7, C8, C10, C12, C14, C16, C18 or C20, etc.; and C3-C20 can be C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C18 or C20, etc.

[0007] Preferably, A is selected from C2-C20 alkylene groups. Any one of them.

[0008] Preferably, X is selected from Any one of them.

[0009] In this invention, the polymer hole transport material achieves dual-interface synergistic optimization and long-term stability: carboxyl or phosphate groups can simultaneously form lead-oxygen coordination bonds with the perovskite layer and hydrogen bonds with the nickel oxide substrate, synchronously optimizing the adhesion of the upper and lower interfaces and improving film adhesion and device mechanical and environmental stability. The polymer hole transport material of this invention is a dimensionally tunable system with broad adaptability: through multi-dimensional molecular engineering design involving side-chain A regulation, X-unit substituent modification, and degree of polymerization adjustment, a series of polymers with tunable performance gradients are constructed to precisely adapt to the energy level matching requirements of perovskite systems with different components, solving the problems of poor energy level adaptability and weak versatility of traditional materials.

[0010] On the other hand, the present invention provides a method for preparing the polymer hole transport material as described above, the method comprising the following steps: (1) Brominated DPP reacts with raw material B to obtain monomer D, as shown in the following reaction formula: ; (2) Monomer D undergoes polymerization under the action of a nickel catalyst to obtain intermediate M, as shown in the following reaction formula: ; (3) Intermediate M undergoes a hydrolysis reaction to obtain polymer P, a polymer hole transport material with general formula (I). The reaction formula is as follows: ; Where R1 is -PO(EtO)2 or -CO2Et, and X1 is selected from halogens (e.g., F, Cl, Br or I).

[0011] The molar ratio of brominated DPP to raw material B in step (1) is 1:(2-10), for example 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, preferably 1:4.

[0012] Preferably, the reaction in step (1) is carried out in the presence of a base.

[0013] Preferably, the alkali is selected from any one or a combination of at least two of sodium hydride, potassium hydroxide, sodium hydroxide, potassium tert-butoxide, sodium tert-butoxide, potassium carbonate, or sodium carbonate, with potassium carbonate being preferred.

[0014] Preferably, the molar ratio of the brominated DPP to the base is 1:(2-10), such as 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, with 1:3 being the most preferred.

[0015] Preferably, when A is selected from C2-C20 alkylene groups, the reaction in step (1) does not require a catalyst; when A is selected from C6-C20 arylene groups, the reaction in step (1) is carried out in the presence of a catalyst and a ligand. Preferably, the catalyst is selected from cuprous iodide or copper powder, with cuprous iodide being the most preferred. Preferably, the amount of catalyst used is 10% to 100% of the molar amount of brominated DPP, such as 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 100%, preferably 50%.

[0016] Preferably, the ligand is selected from any one or a combination of at least two of o-phenanthroline, L-proline, trans-cyclohexanediamine or 8-hydroxyquinoline, with trans-cyclohexanediamine being the preferred choice.

[0017] Preferably, the molar ratio of the ligand to the catalyst is 2:1.

[0018] Preferably, the reaction in step (1) is carried out in a solvent selected from any one or a combination of at least two of DMF, dioxane, DMSO, DMAC or NMP, preferably DMF or DMAC.

[0019] Preferably, the reaction in step (1) is carried out under the protection of a protective gas, preferably nitrogen.

[0020] Preferably, the reaction in step (1) is performed by first stirring the reaction system containing brominated DPP at room temperature for 0.5 to 2 hours (e.g., 0.5 hours, 0.7 hours, 0.9 hours, 1.1 hours, 1.3 hours, 1.5 hours, 1.7 hours, or 2 hours) to complete the pre-activation of the system, then adding raw material B, and then reacting at 80 to 160°C (e.g., 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, or 160°C) for 12 to 48 hours (e.g., 12 hours, 16 hours, 20 hours, 24 hours, 28 hours, 32 hours, 36 hours, 40 hours, 44 hours, or 48 hours).

[0021] Preferably, the nickel catalyst in step (2) is selected from Ni(COD)2 (bis(1,5-cyclooctadiene)nickel) or Ni(bpy)Cl2 (2,2'-bipyridine nickel chloride).

[0022] Preferably, the molar ratio of monomer D to nickel catalyst in step (2) is 1:(1-5), such as 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5 or 1:5.

[0023] Preferably, when the nickel catalyst is bis(1,5-cyclooctadiene)nickel, the reaction in step (2) is carried out in the presence of a ligand, which is at least one of 2,2-bipyridine and 1,5-cyclooctadiene; the amount of the ligand is 1 to 3 times the molar amount of the nickel catalyst (e.g., 1, 1.5, 2, 2.5 or 3 times, etc.).

[0024] Preferably, when the nickel catalyst is 2,2'-bipyridine nickel chloride, the reaction in step (2) is carried out in the presence of a reducing agent, which is zinc powder, and the amount of the reducing agent is 1-3 times the molar amount of the nickel catalyst (e.g., 1, 1.5, 2, 2.5 or 3 times, etc.).

[0025] Preferably, the polymerization reaction in step (2) is carried out in a solvent selected from any one or a combination of at least two of anhydrous N,N-dimethylformamide (DMF), toluene, and tetrahydrofuran (THF), and more preferably DMF or a mixture of DMF and toluene.

[0026] Preferably, the polymerization reaction in step (2) is carried out at a temperature of 60-120°C and for a reaction time of 6-48 hours.

[0027] In this invention, after the polymerization reaction in step (2) is completed, 1M hydrochloric acid is added, and the precipitate is separated by filtration. The polymer is dissolved in dichloromethane, precipitated in diethyl ether, extracted by Soxhlet extraction, and dried under vacuum to obtain intermediate M.

[0028] Preferably, the hydrolysis reaction in step (3) is carried out under acidic or alkaline conditions.

[0029] Preferably, the acidic substance providing the acidic conditions is selected from at least one of trimethylbromosilane, hydrochloric acid, or sulfuric acid.

[0030] Preferably, the alkaline substance providing the alkaline conditions is selected from at least one of lithium hydroxide, sodium hydroxide, or potassium hydroxide.

[0031] Preferably, the molar ratio of the intermediate M to the acidic or alkaline substance is 1:(2-10), such as 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10.

[0032] The hydrolysis reaction in step (3) is carried out in a solvent, which is selected from any one or at least a combination of two of tetrahydrofuran, 1,4-dioxane, and N,N-dimethylformamide; Preferably, the temperature of the hydrolysis reaction in step (3) is 0-50℃ (e.g., 0℃, 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃ or 50℃, etc.), and the reaction time is 10-48 hours (e.g., 10 hours, 15 hours, 20 hours, 25 hours, 30 hours, 35 hours, 40 hours or 48 hours, etc.).

[0033] On the other hand, the present invention provides a perovskite solar cell, the perovskite solar cell including a hole transport layer, the material of the hole transport layer including the polymer hole transport material as described above.

[0034] Preferably, the perovskite solar cell comprises a conductive substrate, a hole transport layer, a perovskite active layer, an electron transport layer, a hole blocking layer, and an electrode layer arranged sequentially.

[0035] Preferably, the hole transport layer is obtained by coating a solution of the polymer hole transport material as described above onto the surface of the anode layer and then performing thermal annealing.

[0036] Compared with the prior art, the present invention has the following beneficial effects: Compared to small-molecule SAM materials, the polymer hole transport material of this invention has a longer conjugation length. This extended conjugation structure promotes the free movement of delocalized π electrons within the unsaturated polymer backbone, creating an electrical pathway for mobile charge carriers. The repeating units in the polymer possess centrosymmetric dual anchoring groups, enabling multiple functional units on the polymer chain to synergistically adsorb onto the substrate surface, forming a denser and more stable self-assembled interface layer. This layer combines the advantages of interface regulation with the polymer's high stability and solvent resistance. The polymer exhibits good electrical conductivity, thus being less sensitive to layer thickness and substrate surface roughness, broadening the processing window. Simultaneously, the carbonyl group contains lone pair electrons, which can coordinate and passivate perovskite defects, further enhancing interface stability. When applied to inverted perovskite solar cell devices, this results in perovskite solar cells with open-circuit voltages above 1.0V and short-circuit currents above 17 mA / cm². 2 The fill factor is above 74%, the efficiency is above 14%, the efficiency retention rate is above 90% after 100 hours of light aging, and the efficiency retention rate is above 86% after 200 hours of light aging, demonstrating good stability and improving operational reliability. Detailed Implementation

[0037] 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.

[0038] In this invention, the polymer molecular weight was tested using a gel permeation chromatograph (GPC) model PL-GPC120, a differential detector, a PLgel10um MIXED-B300×7.5mm column, a DMF mobile phase, a flow rate of 1ml / min, a temperature of 40℃, and a PS standard.

[0039] Examples 1-3 DPP1 is a publicly disclosed compound, CAS: 777079-55-7; The values ​​of m are 2, 4, and 8. Example 1 When m is 2, it corresponds to monomer D1, intermediate M1, and final product P1.

[0040] (1) Add 4.6 g of DPP1, 4.2 g of anhydrous potassium carbonate, and 50 mL of DMF to a dry reaction flask, stir at room temperature for 30 min, then add 7.2 g of ethyl 3-bromopropionate and heat to 100 °C. Stir the reaction under a nitrogen atmosphere for 24 h. After the reaction solution cools to room temperature, pour it into 200 mL of ice water to precipitate a solid crude product; filter, wash the filter cake with water until neutral, concentrate the organic phase, and purify the crude product by column chromatography to obtain monomer D1; 1H NMR data for monomer D1: 1 H NMR (600 MHz, CDCl3) δ 7.41 (d, J = 4.0 Hz,2H), 7.08 (d, J = 4.0 Hz, 2H), 4.13 (q, J = 7.2 Hz, 4H), 3.76 (t, J = 7.0 Hz,4H), 2.61 (t, J = 7.0 Hz, 4H), 1.22 (t, J = 7.2 Hz, 6H).

[0041] (2) Weigh 1.65 g of Ni(COD)2, 0.94 g of 2,2-bipyridine, and 0.65 g of 1,5-cyclooctadiene in a glove box, add 40 mL of ultra-dry DMF, heat to 80 °C under nitrogen atmosphere, and react for half an hour; dissolve 2.8 g of monomer D1 in 20 mL of ultra-dry DMF, and slowly add this solution dropwise to the above-heated solution under nitrogen atmosphere, and continue the reaction at 80 °C for 8 hours; cool to room temperature, add 50 mL of dilute hydrochloric acid (1 M), and separate the precipitate by filtration. Then dissolve the polymer in dichloromethane, recrystallize in diethyl ether, and obtain a dark red intermediate M1 by Soxhlet extraction and vacuum drying. Molecular weight M w =4888, n=6.

[0042] 1H NMR data for intermediate M1: 1 H NMR (400 MHz, CDCl3): 7.21–7.27 (m, 2H), 6.91–6.97 (m, 2H), 4.11–4.17 (m, 4H), 3.84–3.90 (m, 4H), 2.54–2.60 (m, 4H), 1.23–1.29 (m, 6H).

[0043] (3) Dissolve 1g of D1 in 20mL of THF, keep the temperature below 10℃ in an ice-water bath, add 0.3g of potassium hydroxide, remove the ice bath and restore the room temperature for 12 hours, then concentrate most of the THF and add 15mL of water; adjust the pH to 45 with 1M dilute hydrochloric acid, precipitate the solid, filter to obtain a dark red solid, which is the hole transport polymer P1.

[0044] 1H NMR data of the final product P1: 1 H NMR (400 MHz, CDCl3, ppm): 7.18-7.24 (m,2H), 6.88-6.94 (m, 2H), 3.82-3.88 (m, 4H), 2.52-2.58 (m, 4H).

[0045] Example 2 When m is 4, it corresponds to monomer D2, intermediate M2, and final product P2. (1) Synthesis of monomer D2 4.6 g of DPP1, 4.2 g of anhydrous potassium carbonate, and 50 mL of DMF were added to a dry reaction flask and stirred at room temperature for 30 min. Then, 8.3 g of ethyl 5-bromopentanoate was added, and the temperature was raised to 100 °C. The reaction was stirred under a nitrogen atmosphere for 24 h. After the reaction solution cooled to room temperature, it was poured into 200 mL of ice water, and a solid crude product precipitated. The product was filtered, the filter cake was washed with water until neutral, and the organic phase was concentrated. The crude product was purified by column chromatography to obtain monomer D2.

[0046] Monomer D2 1 H NMR (600 MHz, CDCl3) δ 7.37 (d, J=4.1 Hz, 2H), 7.18 (d, J=4.1 Hz, 2H), 4.14 (q, J=7.1 Hz, 4H), 3.99 (t, J=7.3 Hz, 4H), 2.35 (t, J=7.0Hz, 4H), 1.73-1.64 (m, 8H), 1.26 (t, J=7.1 Hz, 6H).

[0047] (2) Synthesis of intermediate M2: Weigh 1.65 g of Ni(COD)₂, 0.94 g of 2,2-bipyridine, and 0.65 g of 1,5-cyclooctadiene in a glove box. Add 40 mL of ultra-dry DMF and heat to 80 °C under nitrogen atmosphere, reacting for half an hour. Dissolve 2.8 g of monomer D21 in 20 mL of ultra-dry DMF. Slowly add this solution dropwise to the heated solution under nitrogen atmosphere, and continue the reaction at 80 °C for 8 hours. Cool to room temperature, add 50 mL of dilute hydrochloric acid (1 M), and separate the precipitate by filtration. Then dissolve the polymer in dichloromethane, recrystallize in diethyl ether, and obtain a dark red intermediate M2 by Soxhlet extraction and vacuum drying.

[0048] intermediate M2 1H NMR (600 MHz, CDCl3, ppm): 6.92-7.22 (m, 4H), 4.10-4.16(m, 4H), 3.70-3.75 (m, 4H), 2.30-2.36 (m, 4H), 1.60-1.76 (m, 8H), 1.22-1.28(m, 6H);M w =6011, n=8.

[0049] (3) Synthesis of the final product P2: Dissolve 1g of M2 in 20mL of THF, maintain the temperature below 10℃ in an ice-water bath, add 0.3g of potassium hydroxide, remove the ice bath and restore the room temperature for 12 hours, then concentrate most of the THF and add 15mL of water; adjust the pH to 45 with 1M dilute hydrochloric acid, precipitate the solid, filter to obtain a dark red solid, which is the hole transport polymer P2.

[0050] 1 H NMR (400 MHz, CDCl3): 7.20-7.26 (m, 2H), 6.90-6.96 (m, 2H), 3.70-3.76 (m, 4H), 2.30-2.38 (m, 4H), 1.60-1.78 (m, 8H).

[0051] Example 3 When m is 6, it corresponds to monomer D3, intermediate M3, and final product P3. (1) Synthesis of monomer D3: 4.6 g of DPP1, 4.2 g of anhydrous potassium carbonate, and 50 mL of DMF were added to a dry reaction flask. The mixture was stirred at room temperature for 30 min, followed by the addition of 9.5 g of ethyl 7-bromoheptanoate. The mixture was heated to 100 °C and stirred under a nitrogen atmosphere for 24 h. After the reaction solution cooled to room temperature, it was poured into 200 mL of ice water, precipitating a crude solid product. The product was filtered, the filter cake was washed with water until neutral, and the organic phase was concentrated. The crude product was then purified by column chromatography to obtain monomer D3.

[0052] 1H NMR (400 MHz, CDCl3) δ 7.39 (d, J = 4.0 Hz, 2H), 7.18 (d, J = 4.0Hz, 2H), 4.18 (q, J = 7.2 Hz, 4H), 4.04 (t, J = 7.0 Hz, 4H), 2.29 (t, J = 7.2Hz, 4H), 1.62-1.70 (m, 8H), 1.34-1.48 (m, 8H), 1.24 (t, J = 7.2 Hz, 6H).

[0053] (2) Synthesis of intermediate M3: Weigh 1.65 g of Ni(COD)₂, 0.94 g of 2,2-bipyridine, and 0.65 g of 1,5-cyclooctadiene in a glove box. Add 40 mL of ultra-dry DMF and heat to 80 °C under nitrogen atmosphere, reacting for half an hour. Dissolve 2.8 g of monomer D3 in 20 mL of ultra-dry DMF, and slowly add this solution dropwise to the heated solution under nitrogen atmosphere. Continue the reaction at 80 °C for 8 hours. Cool to room temperature, add 50 mL of dilute hydrochloric acid (1 M), and separate the precipitate by filtration. Then dissolve the polymer in dichloromethane, recrystallize in diethyl ether, and obtain a dark red intermediate M3 by Soxhlet extraction and vacuum drying.

[0054] 1 H NMR (400 MHz, CDCl3):7.17-7.23 (m, 2H), 6.87-6.93 (m, 2H), 4.08-4.14 (m, 4H), 3.66-3.72 (m, 4H), 2.24-2.30 (m, 4H), 1.50-1.75 (m, 16H), 1.20-1.26 (m, 6H); MW=9323, n=15.

[0055] (3) Synthesis of the final product P3: Dissolve 1g of M3 in 20mL of THF, maintain the temperature below 10℃ in an ice-water bath, add 0.3g of potassium hydroxide, remove the ice bath and restore the room temperature for 12 hours, then concentrate most of the THF and add 15mL of water; adjust the pH to 45 with 1M dilute hydrochloric acid, precipitate the solid, filter to obtain a dark red solid, which is the hole transport polymer P3.

[0056] 1H NMR (400 MHz, CDCl): 7.17-7.23 (m, 2H), 6.87-6.93 (m, 2H), 3.68-3.74 (m, 4H), 2.26-2.32 (m, 4H), 1.54-1.72 (m, 16H).

[0057] Examples 4-6 Examples 4-6: X represents thiophene corresponding to DPP1, which corresponds to Example 4; X represents benzene corresponding to DPP2, which corresponds to Example 5; X represents pyridine corresponding to DPP3, which corresponds to Example 6. The corresponding structures for DPP1, DPP2, and DPP3 are as follows: DPP1, DPP2, and DPP3 are publicly disclosed compounds. DPP1, CAS: 777079-55-7; DPP2, CAS: 84632-54-2; DPP3, CAS: 777079-50-2.

[0058] Example 4 (1) Preparation of monomer D4 4.6 g of DPP1, 4.2 g of anhydrous potassium carbonate, 0.95 g of cuprous iodide, 1.2 g of trans-cyclohexanediamine, and 50 mL of DMAC were added to a dry reaction flask. The mixture was stirred at room temperature for 30 min, followed by the addition of 11.7 g of diethyl 4-bromophenyl phosphate. The temperature was raised to 100 °C, and the reaction was stirred under a nitrogen atmosphere for 24 h. After the reaction solution cooled to room temperature, it was poured into 200 mL of ice water, precipitating a crude solid product. The product was filtered, and the filter cake was washed with water until neutral. After concentrating the organic phase, the crude product was purified by column chromatography to obtain monomer D4. 1 H NMR (600 MHz, CDCl3) δ 7.88 (dd, J=8.4,2.2Hz, 4H), 7.72 (dd, J=8.4,2.2Hz, 4H), 7.41 (d, J=4.0Hz, 2H), 6.92 (d, J=4.0 Hz, 2H), 4.18 (dq, J=7.0,7.0Hz, 8H), 1.34 (t, J=7.0Hz, 12H).

[0059] (2) Preparation of intermediate M4 Weigh 1.65 g of Ni(COD)₂, 0.94 g of 2,2-bipyridine, and 0.65 g of 1,5-cyclooctadiene in a glove box. Add 40 mL of ultra-dry DMF and heat to 80 °C under nitrogen atmosphere, reacting for half an hour. Dissolve 2.4 g of monomer D4 in 30 mL of ultra-dry DMF, and slowly add this solution dropwise to the heated solution under nitrogen atmosphere. Continue the reaction at 80 °C for 8 hours. Cool to room temperature, add 50 mL of dilute hydrochloric acid (1 M), and separate the precipitate by filtration. Then dissolve the polymer in dichloromethane, recrystallize in diethyl ether, and obtain a dark red intermediate M4 by Soxhlet extraction and vacuum drying. M4 is then... w =3617, n=4.

[0060] intermediate M4 1 H NMR (400 MHz, CDCl3): 7.84-7.92 (m, 4H), 7.68-7.76 (m, 4H), 7.38-7.44 (m, 2H), 6.88-6.96 (m, 2H), 4.12-4.24 (m, 8H), 1.28-1.38 (m, 12H).

[0061] (3) Preparation of P4 Dissolve 1g of D4 in 30mL of 1,4-dioxane and stir at room temperature until dissolved. Add 5mL of trimethylbromosilane and react at room temperature for 24 hours. After post-treatment, concentrate most of the 1,4-dioxane and add 30mL of water. The precipitated solid was filtered to obtain a dark red solid, which is the hole transport polymer P4.

[0062] Final product P4 1 H NMR (400 MHz, CDCl3):7.80-7.88 (m, 4H), 7.65-7.73 (m, 4H), 7.36-7.42 (m, 2H), 6.86-6.94 (m, 2H).

[0063] Example 5 (1) Synthesis of monomer D5: 4.46 g of DPP2, 4.2 g of anhydrous potassium carbonate, 0.95 g of cuprous iodide, 1.2 g of trans-cyclohexanediamine, and 50 mL of DMAC were added to a dry reaction flask. The mixture was stirred at room temperature for 30 min, followed by the addition of 11.7 g of diethyl 4-bromophenyl phosphate. The temperature was raised to 100 °C, and the reaction was stirred under a nitrogen atmosphere for 24 h. After the reaction solution cooled to room temperature, it was poured into 200 mL of ice water, precipitating a crude solid product. The product was filtered, and the filter cake was washed with water until neutral. After concentrating the organic phase, the crude product was purified by column chromatography to obtain monomer D5. 1H NMR (400 MHz, CDCl3) δ 7.99-8.04 (m, 4H), 7.49-7.54 (d, J=8.5 Hz, 4H), 7.35-7.40 (d, J=8.3 Hz, 4H), 7.20-7.25 (d, J=8.5 Hz, 4H), 4.04 (dq, J=7.1, 8.2 Hz, 8H), 1.31 (t, J=7.1 Hz, 12H).

[0064] (2) Synthesis of intermediate M5: Weigh 1.65 g of Ni(COD)₂, 0.94 g of 2,2-bipyridine, and 0.65 g of 1,5-cyclooctadiene in a glove box. Add 40 mL of ultra-dry DMF and heat to 80 °C under nitrogen atmosphere, reacting for half an hour. Dissolve 2.4 g of monomer D5 in 30 mL of ultra-dry DMF, and slowly add this solution dropwise to the heated solution under nitrogen atmosphere. Continue the reaction at 80 °C for 8 hours. Cool to room temperature, add 50 mL of dilute hydrochloric acid (1 M), and separate the precipitate by filtration. Then dissolve the polymer in dichloromethane, recrystallize in diethyl ether, and obtain a dark red intermediate M5 by Soxhlet extraction and vacuum drying.

[0065] 1 H NMR (400 MHz, CDCl3): 7.82-7.90 (m, 4H), 7.66-7.74 (m, 4H), 7.50-7.58 (m, 4H), 7.38-7.46 (m, 4H), 4.14-4.22 (m, 8H), 1.30-1.36 (m, 12H); MW=2926, n=3.

[0066] (3) Synthesis of the final product P5: Dissolve 1g of M5 in 30mL of 1,4-dioxane and stir at room temperature until dissolved. Add 5mL of trimethylbromosilane and react at room temperature for 24 hours. After post-treatment, concentrate most of the 1,4-dioxane and add 30mL of water. The precipitated solid was filtered to obtain a dark red solid, which is the hole transport polymer P5.

[0067] 1 H NMR (400 MHz, CDCl3): 7.78-7.86 (m, 4H), 7.62-7.70 (m, 4H), 7.46-7.54 (m, 4H), 7.34-7.42 (m, 4H).

[0068] Example 6 (1) Synthesis of monomer D6: 4.48 g of DPP1, 4.2 g of anhydrous potassium carbonate, 0.95 g of cuprous iodide, 1.2 g of trans-cyclohexanediamine, and 50 mL of DMAC were added to a dry reaction flask. The mixture was stirred at room temperature for 30 min, followed by the addition of 11.7 g of diethyl 4-bromophenyl phosphate. The temperature was raised to 100 °C, and the reaction was stirred under a nitrogen atmosphere for 24 h. After the reaction solution cooled to room temperature, it was poured into 200 mL of ice water, precipitating a crude solid product. The product was filtered, and the filter cake was washed with water until neutral. After concentrating the organic phase, the crude product was purified by column chromatography to obtain monomer D6.

[0069] 1 H NMR (400 MHz, CDCl3): δ 8.42 (d, J = 1.6 Hz, 2H), 7.72-7.79 (m,2H), 7.62 (dd, J = 8.5, 1.7 Hz, 4H), 7.43-7.47 (m, 2H), 7.33 (d, J = 8.5 Hz,4H), 7.28-7.36 (m, 2H), 4.18 (q, J = 7.1 Hz, 8H), 1.34 (t, J = 7.1 Hz, 12H).

[0070] (2) Synthesis of intermediate M6: Weigh 1.65 g of Ni(COD)₂, 0.94 g of 2,2-bipyridine, and 0.65 g of 1,5-cyclooctadiene in a glove box. Add 40 mL of ultra-dry DMF and heat to 80 °C under nitrogen atmosphere, reacting for half an hour. Dissolve 2.4 g of monomer D6 in 30 mL of ultra-dry DMF, and slowly add this solution dropwise to the heated solution under nitrogen atmosphere. Continue the reaction at 80 °C for 8 hours. Cool to room temperature, add 50 mL of dilute hydrochloric acid (1 M), and separate the precipitate by filtration. Then dissolve the polymer in dichloromethane, recrystallize in diethyl ether, and obtain a dark red intermediate M6 by Soxhlet extraction and vacuum drying.

[0071] 1 H NMR (400 MHz, CDCl3):8.42-8.48 (m, 2H), 7.82-7.90 (m, 4H), 7.66-7.74 (m, 4H), 7.44-7.50 (m, 2H), 7.28-7.36 (m, 2H), 4.14-4.22 (m, 8H), 1.30-1.36 (m, 12H); M w =2620, n=3.

[0072] (3) Synthesis of the final product P6: Dissolve 1g of M6 in 30mL of 1,4-dioxane and stir at room temperature until dissolved. Add 5mL of trimethylbromosilane and react at room temperature for 24 hours. After post-treatment, concentrate most of the 1,4-dioxane and add 30mL of water. The precipitated solid was filtered to obtain a dark red solid, which is the hole transport polymer P6.

[0073] 1 H NMR (400 MHz, CDCl3): 8.40-8.46 (m, 2H), 7.76-7.84 (m, 4H), 7.60-7.68 (m, 4H), 7.42-7.48 (m, 2H), 7.26-7.34 (m, 2H).

[0074] Application Example 1 This embodiment also provides a perovskite solar cell, which includes a conductive substrate, a hole transport layer, a perovskite active layer, an electron transport layer, a hole blocking layer, and an electrode layer stacked sequentially.

[0075] Its preparation method includes the following steps: 1. Cleaning of ITO conductive glass: The ITO conductive glass was ultrasonically cleaned for 30 minutes each time using soapy water, deionized water, acetone, and isopropanol, respectively; after drying the substrate with nitrogen, it was treated with ultraviolet ozone for 30 minutes. 2. Hole transport layer preparation: Hole transport material P1 was dissolved in DMSO to prepare a 0.5 mg / mL solution. This solution was drop-coated onto the cleaned ITO substrate surface and spin-coated at 3000 rpm for 30 s, followed by annealing at 100 °C for 10 min to complete the deposition of a self-assembled monolayer film. 3. Preparation of perovskite thin films: The perovskite precursor solution selected has a composition of FA. 0.95 Cs 0.05The perovskite precursor solution contained PbI3 at a concentration of 1.61 mol·L⁻¹. The perovskite precursor solution was prepared as follows: a mixture of 19.5 mg CsI, 245.5 mg FAI, and 691.4 mg PbI₂ powders was dissolved in 1 mL of anhydrous DMF / DMSO mixture (4 / 1, v / v). The solution was magnetically stirred overnight at room temperature and then filtered through a 0.22 μm polytetrafluoroethylene (PTFE) syringe filter. For the thin film spin-coating process: 70 μL of the above precursor solution was drop-coated onto the hole transport layer surface using a single-step spin-coating program at a speed of 5000 rpm for 60 s, with a speed increase rate of 1000 rpm / s. At the 30th s mark of spin-coating, 350 μL of ethyl acetate (EA) was rapidly added drop-coated into the center of the rotating substrate within 1 s as an antisolvent. Immediately after spin coating, the wet film was transferred to a heating stage and annealed at 100°C for 10 min to complete the preparation of the perovskite thin film.

[0076] 4. Fabrication of the functional layer and its metal electrode layer: A 35nm C60 layer (as an electron transport layer) and a 7nm BCP layer were deposited on the surface of the perovskite thin film. Finally, a 100nm Ag electrode was deposited as a hole blocking layer to complete the fabrication of the perovskite solar cell device. The effective area of ​​the device was 0.06cm². 2 Using a xenon lamp solar simulator with a light source intensity of AM 1.5G and 100mW / cm², the open-circuit voltage, short-circuit current, and fill factor of the fabricated battery device were tested.

[0077] Application Example 2-6 Unlike Application Example 1, the hole transport material P1 prepared in Example 1 was replaced with the hole transport materials prepared in Examples 2-6, respectively, to prepare perovskite solar cells.

[0078] Application Examples 1-6 involve narrow bandgap perovskite solar energy systems with a bandgap of ~1.54 eV.

[0079] Comparative Example 1 Unlike Application Example 1, the hole transport material P1 prepared in Example 1 was replaced with commercially available PTAA material (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine, purchased from Maclean, molecular weight Mn=15000, Mw=25000).

[0080] Comparative Example 2 Unlike Application Example 1, the hole transport material P1 prepared in Example 1 was replaced with commercially available PDPPT-TT material (purchased from Maclean, CAS 1260685-66-2, Mw=50k, Mn=140k).

[0081] Performance testing The solar cells fabricated in the above embodiments and comparative examples were placed in a solar simulator. Under the illumination of a certain solar intensity, a bias voltage was applied to the device using a test source meter, and the output current of the device was tested to obtain the bias current density curve. The test data are shown in Table 1.

[0082] Table 1 The solar cells fabricated in the above application examples and comparative examples were subjected to light / thermal aging stability degradation data tests. The test parameters were AM1.5G and 100 mW / cm². 2 The test was conducted at a constant temperature of 60℃ under a nitrogen atmosphere, and the results are shown in Table 2.

[0083] Table 2 This material can be used in perovskite solar cells with different band gaps, as shown below for wide band gap perovskite systems (Cs). 0.15 FA 0.85 PbI 1.8 Br 1.2 Application example 7-12 (band gap ~1.68 eV).

[0084] Application Example 7 This embodiment also provides a perovskite solar cell, which includes a conductive substrate, a hole transport layer, a perovskite active layer, an electron transport layer, a hole blocking layer, and an electrode layer stacked sequentially.

[0085] Its preparation method includes the following steps: 1. Cleaning of ITO conductive glass: The ITO conductive glass was ultrasonically cleaned for 30 minutes each time using soapy water, deionized water, acetone, and isopropanol, respectively; after drying the substrate with nitrogen, it was treated with ultraviolet ozone for 30 minutes. 2. Hole transport layer preparation: Hole transport material P1 was dissolved in DMSO to prepare a 0.5 mg / mL solution. This solution was drop-coated onto the cleaned ITO substrate surface and spin-coated at 3000 rpm for 30 s, followed by annealing at 100 °C for 10 min to complete the deposition of a self-assembled monolayer film. 3. Preparation of perovskite thin films: The perovskite precursor solution selected has a composition of Cs. 0.15 FA 0.85 PbI 1.8 Br 1.2 The concentration of the perovskite precursor solution was 1.61 mol·L⁻¹. -1Consistent with the narrowband system, the perovskite precursor solution was prepared as follows: A mixture of 62.7 mg CsI, 235.3 mg FAI, 296.9 mg PbI2, and 354.5 mg PbBr2 powders was dissolved in 1 mL of anhydrous DMF / DMSO mixture (4 / 1, v / v). The solution was magnetically stirred overnight at room temperature and then filtered through a 0.22 μm polytetrafluoroethylene (PTFE) syringe filter. Thin-film spin-coating process: 70 μL of the above precursor solution was dropped onto the hole transport layer surface using a single-step spin-coating program at a speed of 5000 rpm and a spin-coating time of 60 s, with a speed increase rate of 1000 rpm / s. At the 30th second of spin-coating, 350 μL of chlorobenzene (CB) was rapidly added to the center of the rotating substrate within 1 second as an anti-solvent. Immediately after spin coating, the wet film was transferred to a heating stage and annealed at 110°C for 15 min to complete the preparation of the perovskite thin film.

[0086] 4. Fabrication of the functional layer and its metal electrode layer: A 35nm C60 layer (as an electron transport layer) and a 7nm BCP layer were deposited on the surface of the perovskite thin film. Finally, a 100nm Ag electrode was deposited as a hole blocking layer to complete the fabrication of the perovskite solar cell device. The effective area of ​​the device was 0.06cm². 2 .

[0087] Application Example 8-12 Unlike Application Example 1, the hole transport material P1 prepared in Example 1 was replaced with the hole transport materials prepared in Examples 2-6, respectively, to prepare perovskite solar cells.

[0088] Using a xenon lamp solar simulator, with a light source intensity of AM 1.5G and 100mW cm⁻¹, the open-circuit voltage, short-circuit current, and fill factor of the fabricated battery device were tested.

[0089] The test results are shown in Table 3.

[0090] Table 3 The solar cells fabricated in the above application examples and comparative examples were subjected to light / thermal aging stability degradation data tests. The test parameters were AM1.5G and 100 mW / cm². 2 The test was conducted at a constant temperature of 60℃ under a nitrogen atmosphere, and the results are shown in Table 4.

[0091] Table 4 As can be seen from the data in Tables 1-4 above, the polymer hole transport material of the present invention can be applied to both narrow-bandgap and wide-bandgap perovskite solar cells, resulting in an open-circuit voltage of over 1.0V and a short-circuit current of 17mA / cm² for perovskite solar cells. 2 The fill factor is above 74%, the efficiency is above 14%, the efficiency retention rate is above 90% after 100 hours of light aging, and the efficiency retention rate is above 86% after 200 hours of light aging, which is far better than the performance of perovskite solar cells using comparative materials.

[0092] This invention illustrates the polymer hole transport material and perovskite solar cell 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 raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

Claims

1. A polymer hole transport material, characterized in that, The polymer hole transport material has the structure shown in general formula (I): ； Wherein, A is selected from C2-C20 alkylene or C6-C20 arylene; R is selected from phosphate group or carboxylic acid group; X is selected from C6-C20 aryl or C3-C20 heteroaryl; The degree of aggregation n is an integer between 2 and 100.

2. The polymer hole transport material according to claim 1, characterized in that, A is selected from C2-C20 alkylene groups. Any one of them; Preferably, X is selected from Any one of them; Preferably, n is an integer between 3 and 20.

3. The method for preparing the polymer hole transport material according to claim 1 or 2, characterized in that, The preparation method includes the following steps: (1) Brominated DPP reacts with raw material B to obtain monomer D, as shown in the following reaction formula: ； (2) Monomer D undergoes polymerization under the action of a nickel catalyst to obtain intermediate M, as shown in the following reaction formula: ； (3) Intermediate M undergoes a hydrolysis reaction to obtain polymer P, a polymer hole transport material with general formula (I). The reaction formula is as follows: ； Where R1 is -PO(EtO)2 or -CO2Et, and X1 is selected from halogens.

4. The preparation method according to claim 3, characterized in that, In step (1), the molar ratio of brominated DPP to raw material B is 1:(2-10), preferably 1:4; Preferably, the reaction in step (1) is carried out in the presence of a base; Preferably, the alkali is selected from any one or a combination of at least two of sodium hydride, potassium hydroxide, sodium hydroxide, potassium tert-butoxide, sodium tert-butoxide, potassium carbonate, or sodium carbonate, with potassium carbonate being preferred; Preferably, the molar ratio of the brominated DPP to the base is 1:(2-10), more preferably 1:3; Preferably, when A is selected from C2-C20 alkylene groups, the reaction in step (1) does not require a catalyst; when A is selected from C6-C20 arylene groups, the reaction in step (1) is carried out in the presence of a catalyst and a ligand. Preferably, the catalyst is selected from cuprous iodide or copper powder, with cuprous iodide being the most preferred. Preferably, the amount of catalyst used is 10% to 100% of the molar amount of brominated DPP, more preferably 50%; Preferably, the ligand is selected from any one or a combination of at least two of o-phenanthroline, L-proline, trans-cyclohexanediamine or 8-hydroxyquinoline, with trans-cyclohexanediamine being preferred; Preferably, the molar ratio of the ligand to the catalyst is 2:1; Preferably, the reaction in step (1) is carried out in a solvent selected from any one or a combination of at least two of DMF, dioxane, DMSO, DMAC or NMP, preferably DMF or DMAC; Preferably, the reaction in step (1) is carried out under the protection of a protective gas, preferably nitrogen. Preferably, the reaction in step (1) is performed by first stirring the reaction system containing brominated DPP at room temperature for 0.5 to 2 hours to complete the pre-activation of the system, then adding raw material B, and then reacting at 80 to 160°C for 12 to 48 hours. Preferably, the nickel catalyst in step (2) is selected from bis(1,5-cyclooctadiene) nickel or 2,2'-bipyridine nickel chloride; Preferably, the molar ratio of monomer D to nickel catalyst in step (2) is 1:(1-5). Preferably, when the nickel catalyst is bis(1,5-cyclooctadiene)nickel, the reaction in step (2) is carried out in the presence of a ligand, wherein the ligand is at least one of 2,2-bipyridine and 1,5-cyclooctadiene; the amount of the ligand is 1-3 times the molar amount of the nickel catalyst; Preferably, when the nickel catalyst is 2,2'-bipyridine nickel chloride, the reaction in step (2) is carried out in the presence of a reducing agent, which is zinc powder, and the amount of the reducing agent is 1-3 times the molar amount of the nickel catalyst.

5. The preparation method according to claim 3 or 4, characterized in that, The polymerization reaction in step (2) is carried out in a solvent, which is selected from any one or a combination of at least two of anhydrous N,N-dimethylformamide, toluene, and tetrahydrofuran, and is further preferred to be anhydrous N,N-dimethylformamide or a mixed solvent of anhydrous N,N-dimethylformamide and toluene. Preferably, the polymerization reaction in step (2) is carried out at a temperature of 60-120°C and for a reaction time of 6-48 hours.

6. The preparation method according to any one of claims 3-5, characterized in that, The hydrolysis reaction described in step (3) is carried out under acidic or alkaline conditions; Preferably, the acidic substance providing the acidic conditions is selected from at least one of trimethylbromosilane, hydrochloric acid, or sulfuric acid; Preferably, the alkaline substance providing the alkaline conditions is selected from at least one of lithium hydroxide, sodium hydroxide, or potassium hydroxide; Preferably, the molar ratio of the intermediate M to the acidic or alkaline substance is 1:(2-10).

7. The preparation method according to any one of claims 3-6, characterized in that, The hydrolysis reaction in step (3) is carried out in a solvent, which is selected from any one or at least a combination of two of tetrahydrofuran, 1,4-dioxane, and N,N-dimethylformamide; Preferably, the temperature of the hydrolysis reaction in step (3) is 0-50℃ and the reaction time is 10-48 hours.

8. A perovskite solar cell, characterized in that, The perovskite solar cell includes a hole transport layer, and the material of the hole transport layer includes the polymer hole transport material as described in claim 1 or 2.

9. The perovskite solar cell according to claim 8, characterized in that, The perovskite solar cell comprises a conductive substrate, a hole transport layer, a perovskite active layer, an electron transport layer, a hole blocking layer, and an electrode layer arranged sequentially.

10. The perovskite solar cell according to claim 8 or 9, characterized in that, The hole transport layer is obtained by coating a solution of the polymer hole transport material as described above onto the surface of the anode layer and then performing thermal annealing.

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