An in-situ synthesized hole transport material, its preparation method and application
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-17
- Publication Date
- 2026-08-14
AI Technical Summary
但是，上述两类材料原料成本较高，且本征电导率较低，实际器件制备中通常需要引入双三氟甲磺酰亚胺锂(LiTFSI)等p型掺杂剂以及4-叔丁基吡啶等添加剂，以提升空穴传输层的导电性
[0029]1）本发明通过在含Si-SFA的空穴传输材料体系中引入F4-TCNQ电子受体分子，实现对空穴传输层能级结构的调节，使材料在钙钛矿/空穴传输层界面处形成更有利于空穴抽取的能级匹配关系；
Smart Images
Figure CN122562831A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of perovskite solar cell technology, and more specifically, relates to an in-situ synthesized hole transport material, its preparation method, and its application. Background Technology
[0002] In recent years, perovskite solar cells using organic-inorganic hybrid perovskite materials as the light-absorbing layer have seen rapid development. These cells have attracted widespread attention from academia and industry due to their lower material and manufacturing costs and considerable energy conversion efficiency; the energy conversion efficiency of single-junction devices has exceeded 24%. In the structure of perovskite solar cell devices, besides the light-absorbing layer (perovskite active layer), the hole transport layer is equally crucial for improving device performance. The hole transport layer not only needs to effectively extract photogenerated holes generated in the perovskite layer but also needs to efficiently transport them to the electrodes. Simultaneously, it undertakes multiple functions, including passivating perovskite surface defects, blocking electron backpropagation and recombination, and improving device stability.
[0003] Currently, the commonly used hole transport materials in reported high-efficiency perovskite solar cell devices are mainly polytriarylamine (PTAA) and 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD). However, these two types of materials have high raw material costs and low intrinsic conductivity. In actual device fabrication, it is usually necessary to introduce p-type dopants such as lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and additives such as 4-tert-butylpyridine to improve the conductivity of the hole transport layer. However, the introduction of dopants and additives often accelerates the decomposition of perovskite materials and induces corrosion of metal electrodes, thereby significantly reducing the long-term stability of the device and further increasing the fabrication cost.
[0004] Furthermore, reported inorganic hole transport materials (such as NiOx and CuO) have high bulk and interfacial defect densities, which easily lead to carrier recombination, thus limiting further improvements in battery efficiency and stability. Conventional organic small-molecule hole transport materials have low glass transition temperatures and are prone to recrystallization under thermal stress, resulting in poor film morphology stability. While some studies have attempted to use cross-linked hole transport materials to improve film morphology stability, existing cross-linked hole transport materials generally require temperatures above 150°C to trigger the cross-linking reaction, making them unsuitable for low-temperature solution preparation processes and limiting their application in temperature-sensitive scenarios such as flexible perovskite solar cells.
[0005] Therefore, there is an urgent need to provide a hole transport material and its preparation method that can achieve in-situ crosslinking under low temperature conditions, while possessing high hole transport performance and excellent interface stability, so as to effectively improve the efficiency and stability of perovskite solar cells. Summary of the Invention
[0006] To address the aforementioned problems in the existing technology, the technical problem to be solved by the present invention is to provide an in-situ crosslinkable hole transport material and its preparation method, as well as a high-efficiency, high-stability perovskite solar cell prepared based on the material, which exhibits better structural consistency and stability in terms of interface charge transport and recombination control, and can maintain relatively stable device performance under illumination and environmental stress conditions.
[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:
[0008] A method for preparing an in-situ synthesized hole transport material includes the following steps:
[0009] S1. Using 4-bromobenzonitrile and 4-vinylaniline as raw materials, N-(4-cyanophenyl)-N-(4-vinylphenyl)amine was obtained by reacting under palladium catalyst and alkaline conditions.
[0010] S2. Using 2,7-dibromo-9,9'-spirodifluorene and N-(4-cyanophenyl)-N-(4-vinylphenyl)amine obtained in step S1 as raw materials, the reaction is carried out under palladium catalyst and alkaline conditions to obtain vinylspirodifluorene diamine;
[0011] S3. The vinylspirodifluorene diamine and trialkoxysilane obtained in step S2 are subjected to a hydrosilylation reaction under a platinum catalyst to obtain the in-situ synthesized hole transport material Si-SFA.
[0012] The in-situ synthesized hole transport material Si-SFA is prepared by the aforementioned method.
[0013] Preferably, the application of the in-situ synthesized hole transport material Si-SFA as a raw material for the hole transport layer in the fabrication of perovskite solar cells includes the following steps:
[0014] 1) Dissolve Si-SFA in a mixed solvent of anhydrous chlorobenzene and anhydrous tetrahydrofuran, add F4-TCNQ and stir until homogeneous to obtain a hole transport precursor solution; the mass ratio of F4-TCNQ to Si-SFA is 1:8~40.
[0015] 2) Spin-coat the precursor solution obtained in step 1) onto the surface of a conductive substrate to form a wet film;
[0016] 3) The wet film obtained in step 2) is placed in a constant temperature and humidity environment for heat treatment, and an acidic aqueous solution is added to carry out a hydrolysis and condensation reaction to form a cross-linked hole transport layer; the cross-linked hole transport layer is used as the hole transport interface layer of the perovskite solar cell.
[0017] Preferably, in step 1), the volume ratio of anhydrous chlorobenzene to anhydrous tetrahydrofuran is 8:2 to 9:1.
[0018] Preferably, in step 1), the mass concentration of Si-SFA in the mixed solvent is 10~25 mg / mL.
[0019] Preferably, in step 3), the constant temperature and humidity environment conditions are a temperature of 75~85℃ and a relative humidity of 60~70%.
[0020] Preferably, in step 3), the acidic aqueous solution is a dilute acetic acid aqueous solution with a mass fraction of 0.3~1 wt%.
[0021] Preferably, the method further includes a step of fabricating a perovskite solar cell on the cross-linked hole transport layer, specifically including: sequentially fabricating a perovskite light-absorbing layer, an electron transport layer, an interface modification layer, and a metal back electrode on the cross-linked hole transport layer, to obtain a device structure as follows:
[0022] ITO / crosslinked Si-SFA(F4-TCNQ) / FA 0.85 MA 0.15 Pb(I 0.85 Br 0.15 )3 / PC 61 BM / BCP / Ag.
[0023] Preferably, the perovskite light-absorbing layer is prepared as follows:
[0024] In a nitrogen glove box, lead iodide, lead bromide, formamidinium hydroiodate, and methylammonium iodide were dissolved in anhydrous DMF / DMSO mixed solvent and stirred thoroughly to dissolve Pb. 2+ The total concentration was 1.25 mol / L. The perovskite precursor solution was filtered through a 0.22 μm filter membrane before use. The perovskite precursor solution was spin-coated onto the cross-linked hole transport layer in two steps. The spin-coating program was as follows: first step, 1000 rpm for 10 s, second step, 4000 rpm for 20 s. 100 μL of anhydrous chlorobenzene was added to the center of the substrate as an anti-solvent 15 s after the start of the second step. After spin-coating, the substrate was transferred to a hot plate at 100 ℃ and annealed for 10 min to form a perovskite light-absorbing layer.
[0025] Preferably, the electron transport layer is prepared by: after the perovskite layer is cooled to room temperature, spin-coating a PC solution with a concentration of 20 mg / mL is performed inside a glove box. 61 BM chlorobenzene solution, rotation speed 2000 rpm, time 30s, to form an electron transport layer;
[0026] The interface modification layer is prepared by spin-coating a 0.5 mg / mL BCP isopropanol solution onto the electron transport layer at a speed of 4000 rpm for 30 seconds to form the interface modification layer.
[0027] The fabrication process of the metal back electrode is as follows: the substrate is transferred into a vacuum thermal evaporation system, and the vacuum level is better than 5×10⁻⁶. -4 Under Pa conditions, a 100 nm thick Ag electrode was deposited using a metal mask, resulting in an effective device area of 0.09 cm². 2 After the vapor deposition is completed, the perovskite solar cell is encapsulated in a glove box using UV-curable adhesive and cover glass.
[0028] Beneficial effects: Compared with the prior art, the present invention has the following advantages:
[0029] 1) This invention introduces F4-TCNQ electron acceptor molecules into a hole transport material system containing Si-SFA to adjust the energy level structure of the hole transport layer, so that the material forms an energy level matching relationship that is more conducive to hole extraction at the perovskite / hole transport layer interface.
[0030] 2) This invention introduces an acid-catalyzed environment under constant temperature and humidity conditions after spin coating to promote the hydrolysis and condensation reaction of Si-SFA molecules, forming a cross-linked network structure dominated by Si-O-Si bonds, thereby improving the structural stability and film integrity of the hole transport layer.
[0031] 3) The perovskite solar cell constructed based on the hole transport layer of this invention exhibits better structural consistency and stability in terms of interface charge transport and recombination control, and can maintain relatively stable device performance under illumination and environmental stress conditions. Attached Figure Description
[0032] Figure 1 The graph shows a comparison of the photoelectric conversion efficiency of the perovskite solar cells prepared in Examples 1-5 and Comparative Examples 1-2.
[0033] Figure 2 The graph shows a comparison of the open-circuit voltage and fill factor of the devices in Examples 1-5 and Comparative Examples 1-2.
[0034] Figure 3 Comparison diagrams of interface charge recombination resistance of devices in Examples 1-5 and Comparative Examples 1-2;
[0035] Figure 4 The figures show the long-term stability of the devices in Examples 1-5 and Comparative Examples 1-2 under different conditions. Detailed Implementation
[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is further described below with reference to specific embodiments. Unless otherwise specified, the technical means used in the following embodiments are all conventional means well known to those skilled in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.
[0037] Example 1
[0038] This embodiment provides an in-situ synthesized hole transport material and its application in perovskite solar cells, including the following steps:
[0039] 1. Synthesis of Si-SFA:
[0040] 1) Synthesis of intermediate A (N-(4-cyanophenyl)-N-(4-vinylphenyl)amine)
[0041] Under nitrogen protection, 20 mmol of 4-bromobenzonitrile, 22 mmol of 4-vinylaniline, 30 mmol of sodium tert-butoxide, 0.8 mmol of XPhos, and 0.2 mmol of Pd2(dba)3 were added to a dry reaction flask. 100 mL of anhydrous toluene was added, and after stirring, 0.5 mmol of 2,6-di-tert-butyl-4-methylphenol (BHT) was added. The mixture was heated to 100°C and stirred for 18 h. After the reaction was completed, the mixture was cooled to room temperature, and 50 mL of deionized water was added to quench the reaction. The organic phase was collected by separation, and the aqueous phase was extracted twice with ethyl acetate. The combined organic phases were washed once with saturated brine, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using petroleum ether / ethyl acetate (volume ratio 15:1) as eluent to obtain intermediate A.
[0042] 2) Synthesis of V-SFA (vinylspirodifluorene diamine)
[0043] Under nitrogen protection, 8 mmol of 2,7-dibromo-9,9'-spirodifluorene, 18 mmol of intermediate A, 24 mmol of sodium tert-butoxide, and 0.4 mmol of RuPhos Pd G3 catalyst were added to the reaction flask, along with 80 mL of anhydrous toluene and 0.3 mmol of BHT. The mixture was heated to 110°C and stirred for 24 h. After the reaction was completed, the mixture was cooled to room temperature and quenched with 40 mL of deionized water. The organic phase was collected by separation, and the aqueous phase was extracted twice with dichloromethane. The combined organic phases were washed with saturated brine, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography with petroleum ether / dichloromethane, eluting in a gradient of 10:1 to 3:1 (v / v) to obtain V-SFA.
[0044] 3) Synthesis of Si-SFA
[0045] Under nitrogen protection, 5 mmol of V-SFA was dissolved in 30 mL of anhydrous toluene, 13 mmol of triethoxysilane and 20 μL of Karstedt catalyst were added, and the mixture was stirred at 50°C for 8 h. After the reaction was completed, the mixture was cooled to room temperature, filtered through diatomaceous earth, and the filtrate was concentrated under reduced pressure to 5-10 mL. Under nitrogen protection and anhydrous conditions, 5-8 times the volume of anhydrous n-hexane was slowly added dropwise to the concentrate, and the mixture was allowed to stand for crystallization. The solid was collected by suction filtration, recrystallized once with a small amount of toluene / n-hexane mixed solvent, and dried under vacuum at 40°C for 12 h to obtain Si-SFA.
[0046] 2. Preparation of the cross-linked hole transport layer:
[0047] 1) In an inert atmosphere glove box, weigh 16 mg of Si-SFA prepared in step 1, add 1 mL of anhydrous chlorobenzene / anhydrous tetrahydrofuran mixed solvent (volume ratio 9:1) and stir until completely dissolved. Then add 1.2 mg of F4-TCNQ, stir at room temperature in the dark for 30 min, and filter with a 0.22 μm polytetrafluoroethylene filter membrane to obtain the precursor solution.
[0048] 2) The ITO conductive glass was ultrasonically cleaned in acetone and isopropanol for 15 minutes each, rinsed with deionized water, dried with high-purity nitrogen, treated with ultraviolet ozone for 20 minutes, and cooled to room temperature for use.
[0049] 3) Spin-coat 70 μL of precursor solution onto the pretreated ITO substrate surface at 3500 rpm for 30 s to obtain a uniform wet film. After spin-coating, immediately transfer the wet film substrate to a constant temperature and humidity chamber preheated to 75℃ and 65% relative humidity. Place a 1% (w / w) dilute acetic acid aqueous solution in the chamber and maintain the temperature for 50 min. Then remove the substrate, rinse the surface with anhydrous toluene for 30 s, and dry it with high-purity nitrogen to obtain a cross-linked hole transport layer with a thickness of 30 nm.
[0050] 3. Fabrication of perovskite solar cells:
[0051] Using the cross-linked hole transport layer obtained in step 2 as a substrate, a perovskite light-absorbing layer, an electron transport layer, an interface modification layer, and a metal back electrode were sequentially fabricated. The device structure is as follows:
[0052] ITO / Si-SFA(F4-TCNQ) / FA 0.85 MA 0.15 Pb(I 0.85 Br 0.15 )3 / PC 61 BM / BCP / Ag;
[0053] 1) In a nitrogen glove box, weigh lead iodide (PbI2), lead bromide (PbBr2), formamidinium hydroiodate (FAI), and methylammonium iodide (MAI) in a molar ratio of PbI2:PbBr2:FAI:MAI = 0.775:0.225:0.85:0.15. Dissolve them in anhydrous DMF / DMSO mixed solvent (volume ratio 4:1), and stir thoroughly to dissolve Pb. 2+ The total concentration was 1.25 mol / L. The solution was filtered through a 0.22 μm filter membrane before use to obtain a perovskite precursor solution.
[0054] 2) In a nitrogen glove box, the perovskite precursor solution was spin-coated onto the cross-linked hole transport layer in two steps. The spin-coating procedure was as follows: Step 1: 1000 rpm for 10 s; Step 2: 4000 rpm for 20 s. At 15 s after the start of Step 2, 100 μL of anhydrous chlorobenzene was rapidly added to the center of the substrate as an anti-solvent. After spin-coating, the substrate was transferred to a hot plate at 100°C and annealed for 10 min to form a perovskite light-absorbing layer with a thickness of 450 nm.
[0055] 3) After the perovskite layer cools to room temperature, spin-coat 20 mg / mL PC in a glove box. 61 A 50 nm thick electron transport layer was formed by spin-coating a BM chlorobenzene solution at 2000 rpm for 30 s; subsequently, an interface modification layer was formed by spin-coating a 0.5 mg / mL BCP isopropanol solution at 4000 rpm for 30 s.
[0056] 4) Transfer the obtained substrate into a vacuum thermal evaporation system, where the vacuum level is better than 5×10⁻⁶. -4 Under Pa conditions, a 100 nm thick Ag electrode was deposited using a metal mask, resulting in an effective device area of 0.09 cm². 2 After the vapor deposition is completed, the perovskite solar cell is encapsulated in a glove box using UV-curable adhesive and cover glass.
[0057] Example 2
[0058] This embodiment provides an in-situ synthesized hole transport material and its application in perovskite solar cells, including the following steps:
[0059] 1. Synthesis of Si-SFA: Same as step 1 in Example 1;
[0060] 2. Preparation of the cross-linked hole transport layer:
[0061] 1) In an inert atmosphere glove box, weigh 16 mg of Si-SFA obtained in step 1, add 1 mL of anhydrous chlorobenzene / anhydrous tetrahydrofuran mixed solvent (volume ratio 9:1) and stir until completely dissolved, then add 0.4 mg of F4-TCNQ, stir at room temperature in the dark for 30 min, and filter with a 0.22 μm polytetrafluoroethylene filter membrane to obtain the precursor solution;
[0062] 2) The ITO conductive glass was ultrasonically cleaned in acetone and isopropanol for 15 minutes each, rinsed with deionized water, dried with high-purity nitrogen, treated with ultraviolet ozone for 20 minutes, and cooled to room temperature for use.
[0063] 3) Spin-coat 70 μL of precursor solution onto the pretreated ITO substrate surface at 3500 rpm for 30 s to obtain a uniform wet film. After spin-coating, immediately transfer the wet film substrate to a constant temperature and humidity chamber preheated to 75℃ and 65% relative humidity. Place a 0.3% (w / w) dilute acetic acid aqueous solution in the chamber and maintain the temperature for 20 min. Then remove the substrate, rinse the surface with anhydrous toluene for 30 s, and dry it with high-purity nitrogen to obtain a cross-linked hole transport layer with a thickness of 30 nm.
[0064] 3. Fabrication of perovskite solar cells: Same as step 3 in Example 1.
[0065] Example 3
[0066] This embodiment provides an in-situ synthesized hole transport material and its application in perovskite solar cells, including the following steps:
[0067] 1. Synthesis of Si-SFA: Same as step 1 in Example 1;
[0068] 2. Preparation of the cross-linked hole transport layer:
[0069] 1) In an inert atmosphere glove box, weigh 16 mg of Si-SFA prepared in step 1, add 1 mL of anhydrous chlorobenzene / anhydrous tetrahydrofuran mixed solvent (volume ratio 9:1) and stir until completely dissolved, then add 2 mg of F4-TCNQ, stir at room temperature in the dark for 30 min, and filter with a 0.22 μm polytetrafluoroethylene filter membrane to obtain the precursor solution;
[0070] 2) The ITO conductive glass was ultrasonically cleaned in acetone and isopropanol for 15 minutes each, rinsed with deionized water, dried with high-purity nitrogen, treated with ultraviolet ozone for 20 minutes, and cooled to room temperature for use.
[0071] 3) Spin-coat 70 μL of precursor solution onto the pretreated ITO substrate surface at 3500 rpm for 30 s to obtain a uniform wet film. After spin-coating, immediately transfer the wet film substrate to a constant temperature and humidity chamber preheated to 85℃ and 65% relative humidity. Place a 1% (w / w) dilute acetic acid aqueous solution in the chamber and maintain the temperature for 80 min. Then remove the substrate, rinse the surface with anhydrous toluene for 30 s, and dry it with high-purity nitrogen to obtain a cross-linked hole transport layer with a thickness of 30 nm.
[0072] 3. Fabrication of perovskite solar cells: Same as step 3 in Example 1.
[0073] Example 4
[0074] This embodiment provides an in-situ synthesized hole transport material and its application in perovskite solar cells, including the following steps:
[0075] 1. Synthesis of Si-SFA: Same as step 1 in Example 1;
[0076] 2. Preparation of the cross-linked hole transport layer:
[0077] 1) In an inert atmosphere glove box, weigh 16 mg of Si-SFA prepared in step 1, add 1 mL of anhydrous chlorobenzene / anhydrous tetrahydrofuran mixed solvent (volume ratio 8:2) and stir until completely dissolved, then add 1.2 mg of F4-TCNQ, stir at room temperature in the dark for 30 min, and filter with a 0.22 μm polytetrafluoroethylene filter membrane to obtain the precursor solution;
[0078] 2) The ITO conductive glass was ultrasonically cleaned in acetone and isopropanol for 15 minutes each, rinsed with deionized water, dried with high-purity nitrogen, treated with ultraviolet ozone for 20 minutes, and cooled to room temperature for use.
[0079] 3) Spin-coat 70 μL of precursor solution onto the pretreated ITO substrate surface at 4000 rpm for 30 s to obtain a uniform wet film. After spin-coating, immediately transfer the wet film substrate to a constant temperature and humidity chamber preheated to 75℃ and 65% relative humidity. Place a 1% (w / w) dilute acetic acid aqueous solution in the chamber and maintain the temperature for 50 min. Then remove the substrate, rinse the surface with anhydrous toluene for 30 s, and dry it with high-purity nitrogen to obtain a cross-linked hole transport layer with a thickness of 28 nm.
[0080] 3. Fabrication of perovskite solar cells: Same as step 3 in Example 1.
[0081] Example 5
[0082] This embodiment provides an in-situ synthesized hole transport material and its application in perovskite solar cells, including the following steps:
[0083] 1. Synthesis of Si-SFA: Same as step 1 in Example 1;
[0084] 2. Preparation of the cross-linked hole transport layer:
[0085] 1) In an inert atmosphere glove box, weigh 32 mg of Si-SFA prepared in step 1, add 1 mL of anhydrous chlorobenzene / anhydrous tetrahydrofuran mixed solvent (volume ratio 9:1) and stir until completely dissolved, then add 2.4 mg of F4-TCNQ, stir at room temperature in the dark for 30 min, and filter with a 0.22 μm polytetrafluoroethylene filter membrane to obtain the precursor solution;
[0086] 2) The ITO conductive glass was ultrasonically cleaned in acetone and isopropanol for 15 minutes each, rinsed with deionized water, dried with high-purity nitrogen, treated with ultraviolet ozone for 20 minutes, and cooled to room temperature for use.
[0087] 3) Spin-coat 70 μL of precursor solution onto the pretreated ITO substrate surface at 2000 rpm for 30 s to obtain a uniform wet film. After spin-coating, immediately transfer the wet film substrate to a constant temperature and humidity chamber preheated to 75℃ and 65% relative humidity. Place a 1% (w / w) dilute acetic acid aqueous solution in the chamber and maintain the temperature for 70 min. After that, remove the substrate, rinse the surface with anhydrous toluene for 30 s, and dry it with high-purity nitrogen to obtain a cross-linked hole transport layer with a thickness of 65 nm.
[0088] 3. Fabrication of perovskite solar cells: Same as step 3 in Example 1.
[0089] Comparative Example 1
[0090] This comparative example provides an in-situ synthesized hole transport material and its application in perovskite solar cells, including the following steps:
[0091] 1. Synthesis of Si-SFA: Same as step 1 in Example 1;
[0092] 2. Preparation of the cross-linked hole transport layer:
[0093] 1) In an inert atmosphere glove box, weigh 16 mg of Si-SFA prepared in step 1, add 1 mL of anhydrous chlorobenzene / anhydrous tetrahydrofuran mixed solvent (volume ratio 9:1) and stir until completely dissolved. Stir at room temperature in the dark for 30 min, and filter with a 0.22 μm polytetrafluoroethylene filter membrane to obtain the precursor solution.
[0094] 2) The ITO conductive glass was ultrasonically cleaned in acetone and isopropanol for 15 minutes each, rinsed with deionized water, dried with high-purity nitrogen, treated with ultraviolet ozone for 20 minutes, and cooled to room temperature for use.
[0095] 3) Spin-coat 70 μL of precursor solution onto the pretreated ITO substrate surface at 3500 rpm for 30 s to obtain a uniform wet film; after spin-coating, anneal the wet film substrate directly in a high-purity nitrogen glove box at 75°C for 50 min; without constant temperature and humidity chamber wet acid catalysis treatment, the hole transport layer is obtained.
[0096] 3. Fabrication of perovskite solar cells: Same as step 3 in Example 1.
[0097] Comparative Example 2
[0098] This comparative example provides an in-situ synthesized hole transport material and its application in perovskite solar cells, including the following steps:
[0099] 1. Synthesis of V-SFA: V-SFA was prepared by using steps 1) and 2) of step 1 in Example 1;
[0100] 2. Preparation of the cross-linked hole transport layer:
[0101] 1) In an inert atmosphere glove box, weigh 16 mg of V-SFA prepared in step 1, add 1 mL of anhydrous chlorobenzene / anhydrous tetrahydrofuran mixed solvent (volume ratio 9:1) and stir until completely dissolved. Then add 1.2 mg of F4-TCNQ, stir at room temperature in the dark for 30 min, and filter with a 0.22 μm polytetrafluoroethylene filter membrane to obtain the precursor solution.
[0102] 2) The ITO conductive glass was ultrasonically cleaned in acetone and isopropanol for 15 minutes each, rinsed with deionized water, dried with high-purity nitrogen, treated with ultraviolet ozone for 20 minutes, and cooled to room temperature for use.
[0103] 3) Spin-coat 70 μL of precursor solution onto the pretreated ITO substrate surface at 3500 rpm for 30 s to obtain a uniform wet film. After spin-coating, immediately transfer the wet film substrate to a constant temperature and humidity chamber preheated to 75℃ and 65% relative humidity. Place a 1% (w / w) dilute acetic acid aqueous solution in the chamber and keep it at the constant temperature for 50 min to obtain the hole transport layer.
[0104] 3. Fabrication of perovskite solar cells: Same as step 3 in Example 1.
[0105] The samples obtained in Examples 1-5 and Comparative Examples 1-2 were subjected to relevant performance tests. The test methods were as follows:
[0106] 1. Photovoltaic performance testing of the device: A standard AM 1.5G solar simulator (100 mW·cm²) was used. -2The perovskite solar cells prepared in Examples 1-5 and Comparative Examples 1-2 were tested using a calibrated silicon reference cell. Before testing, all devices were placed in a nitrogen glove box for 12 hours to eliminate residual stress and solvent effects. J-V curves were measured using a source meter (Keithley 2400) with a scan voltage range of -0.1 V to 1.2 V and a scan rate of 100 mV·s. -1 Forward and reverse scan data were recorded separately to evaluate the hysteresis effect. Simultaneously, the following parameters were calculated: open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), photoelectric conversion efficiency (PCE), and hysteresis index (HI).
[0107] 2. Electrical performance testing of hole transport layer: The electrical conductivity (σ), hole mobility (μh), and thin film carrier concentration (n) of the hole transport layer thin film were determined by Hall effect testing (Vander Pauw method). The test sample was a standalone ITO / HTL structure thin film prepared with the same process as the device.
[0108] 3. Interface charge recombination analysis (EIS): Electrochemical impedance spectroscopy (EIS) was used to test the interface charge transport characteristics of the device under dark conditions, frequency range: 1 Hz–1 MHz, bias voltage: near Voc (0.9 V), and the recombination resistance (Rrec) and transport resistance (Rtr) were obtained by fitting.
[0109] 4. Stability Testing: Unpackaged devices were subjected to 65% RH environmental stability (room temperature) and continuous illumination stability (1 day of continuous illumination), and PCE retention was recorded. The test results are shown in Tables 1-4.
[0110] Table 1. Photovoltaic performance test results of different embodiments and comparative devices.
[0111]
[0112] Table 2. Test results of electrical performance of hole transport layer in different embodiments and comparative examples
[0113]
[0114] Table 3. Interface charge recombination parameters of different embodiments and comparative devices (EIS fitting results)
[0115]
[0116] Table 4. Stability test results (PCE retention rate) of different embodiments and comparative examples
[0117]
[0118] As shown in Tables 1-4, the embodiments of the present invention significantly improve the electrical performance and interfacial stability of the hole transport layer by introducing a Si-SFA in-situ crosslinking structure, an F4-TCNQ controlled doping system, and a constant temperature and humidity acid catalytic curing process, thereby achieving an overall improvement in the performance of perovskite solar cells. Compared with Comparative Example 1, due to the lack of constant temperature and humidity acid catalytic crosslinking conditions, the hole transport layer structure is not dense enough and the degree of crosslinking is insufficient, resulting in enhanced interfacial recombination (significantly reduced Rrec) and a decrease in Voc and FF. Compared with Comparative Example 2, although a V-SFA system is introduced, the lack of a Si-based crosslinking network structure significantly reduces the carrier migration capability and stability of the thin film, proving that the siloxane crosslinking structure in the present invention plays a key role in constructing a stable three-dimensional charge transport network.
[0119] Depend on Figure 1 As can be seen, the perovskite solar cells prepared in Examples 1-5 of this invention all exhibit high photoelectric conversion efficiency, with Example 1 showing the highest PCE value, which is significantly improved compared to Comparative Examples 1 and 2. This invention effectively improves hole extraction efficiency by constructing a Si-SFA in-situ crosslinked hole transport layer and introducing an F4-TCNQ controlled doping system, thereby enhancing the overall photoelectric conversion performance of the device.
[0120] Depend on Figure 2 It can be seen that the Voc and FF of the devices in the embodiments of the present invention are generally better than those in the comparative examples. Among them, Example 1 exhibits higher Voc and FF, indicating that the cross-linked hole transport layer constructed in the present invention can effectively reduce the non-radiative recombination loss at the interface and improve the selective transport capability of charge carriers.
[0121] Depend on Figure 3 and Figure 4 As can be seen, the devices in the embodiments of the present invention exhibit higher interfacial recombination resistance (Rrec) and better long-term stability retention. The Rrec of Example 1 is significantly higher than that of the comparative example, indicating that the cross-linked hole transport layer constructed in this invention can effectively suppress interfacial carrier recombination behavior, improve charge extraction efficiency, and enhance device stability. Furthermore, under continuous illumination and humid heat conditions, the devices in the embodiments of the present invention still maintain high PCE stability, demonstrating that this structure has a significant advantage in suppressing perovskite layer decomposition and interfacial degradation.
[0122] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing an in-situ synthesized hole transport material, characterized in that, Includes the following steps: S1. Using 4-bromobenzonitrile and 4-vinylaniline as raw materials, N-(4-cyanophenyl)-N-(4-vinylphenyl)amine was obtained by reacting under palladium catalyst and alkaline conditions. S2. Using 2,7-dibromo-9,9'-spirodifluorene and N-(4-cyanophenyl)-N-(4-vinylphenyl)amine obtained in step S1 as raw materials, the reaction is carried out under palladium catalyst and alkaline conditions to obtain vinylspirodifluorene diamine; S3. The vinylspirodifluorene diamine and trialkoxysilane obtained in step S2 are subjected to a hydrosilylation reaction under a platinum catalyst to obtain the in-situ synthesized hole transport material Si-SFA.
2. The in-situ synthesized hole transport material Si-SFA prepared by the preparation method of the in-situ synthesized hole transport material according to claim 1.
3. The application of the in-situ synthesized hole transport material Si-SFA according to claim 2 as a raw material for the hole transport layer in the fabrication of perovskite solar cells, characterized in that, Includes the following steps: 1) Dissolve Si-SFA in a mixed solvent of anhydrous chlorobenzene and anhydrous tetrahydrofuran, add F4-TCNQ and stir until homogeneous to obtain a hole transport precursor solution; the mass ratio of F4-TCNQ to Si-SFA is 1:8~40. 2) Spin-coat the precursor solution obtained in step 1) onto the surface of a conductive substrate to form a wet film; 3) The wet film obtained in step 2) is placed in a constant temperature and humidity environment for heat treatment, and an acidic aqueous solution is added to carry out a hydrolysis and condensation reaction to form a cross-linked hole transport layer; the cross-linked hole transport layer is used as the hole transport interface layer of the perovskite solar cell.
4. The application according to claim 3, characterized in that, In step 1), the volume ratio of anhydrous chlorobenzene to anhydrous tetrahydrofuran is 8:2 to 9:
1.
5. The application according to claim 3, characterized in that, In step 1), the mass concentration of Si-SFA in the mixed solvent is 10~25 mg / mL.
6. The application according to claim 3, characterized in that, In step 3), the constant temperature and humidity environment conditions are a temperature of 75~85℃ and a relative humidity of 60~70%.
7. The application according to claim 3, characterized in that, In step 3), the acidic aqueous solution is a dilute acetic acid aqueous solution with a mass fraction of 0.3~1 wt%.
8. The application according to claim 3, characterized in that, The method also includes a step of fabricating a perovskite solar cell on the cross-linked hole transport layer, specifically including: sequentially fabricating a perovskite light-absorbing layer, an electron transport layer, an interface modification layer, and a metal back electrode on the cross-linked hole transport layer, to obtain a device structure as follows: ITO / Free Si-SFA(F4-TCNQ) / FA 0.85 MA 0.15 Pb(I) 0.85 Br 0.15 )3 / PC 61 BM / BCP / Ag.
9. The application according to claim 8, characterized in that, The preparation process of the perovskite light-absorbing layer is as follows: In a nitrogen glove box, lead iodide, lead bromide, formamidinium hydroiodate, and methylammonium iodide were dissolved in anhydrous DMF / DMSO mixed solvent and stirred thoroughly to dissolve Pb. 2+ The total concentration was 1.25 mol / L. The perovskite precursor solution was filtered through a 0.22 μm filter membrane before use. The perovskite precursor solution was spin-coated onto the cross-linked hole transport layer in two steps. The spin-coating program was as follows: first step, 1000 rpm for 10 s, second step, 4000 rpm for 20 s. 100 μL of anhydrous chlorobenzene was added to the center of the substrate as an anti-solvent 15 s after the start of the second step. After spin-coating, the substrate was transferred to a hot plate at 100 ℃ and annealed for 10 min to form a perovskite light-absorbing layer.
10. The application according to claim 8, characterized in that, The electron transport layer was prepared as follows: after the perovskite layer cooled to room temperature, PC with a concentration of 20 mg / mL was spin-coated inside a glove box. 61 BM chlorobenzene solution, rotation speed 2000 rpm, time 30s, to form an electron transport layer; The interface modification layer is prepared by spin-coating a 0.5 mg / mL BCP isopropanol solution onto the electron transport layer at a speed of 4000 rpm for 30 seconds to form the interface modification layer. The fabrication process of the metal back electrode is as follows: the substrate is transferred into a vacuum thermal evaporation system, and the vacuum level is better than 5×10⁻⁶. -4 Under Pa conditions, a 100 nm thick Ag electrode was deposited using a metal mask, resulting in an effective device area of 0.09 cm². After deposition, the device was encapsulated in a glove box using UV-curable adhesive and a cover glass to obtain a perovskite solar cell.