阅读说明：本技术 一种空穴传输材料及其在钙钛矿太阳能电池中的应用 (Hole transport material and application thereof in perovskite solar cell ) 是由 郭鹍鹏 田霞 李斌 梁效中 李达 单玲玲 刘素平 于 2020-06-09 设计创作，主要内容包括：本发明涉及钙钛矿太阳能电池中新型空穴传输材料技术领域,具体涉及一种空穴传输材料及其在钙钛矿太阳能电池中的应用,分别以螺二芴,双咔唑和螺[芴-9.9’-氧杂蒽]作为中心核,含CF<Sub>3</Sub>衍生物修饰的二苯胺衍生物为外围封端基团,设计并合成一类用于制备高效、稳定钙钛矿太阳能电池的空穴传输材料。其用于制备高效、稳定钙钛矿太阳能电池的空穴传输材料,制备工艺简单、原料易得、价格低廉,非常适宜工业化生产。所制备的电池具有更低的HOMO能级,有利于提高器件的开路电压；良好的疏水性,有利于提高器件的稳定性；较高的空穴迁移率。其器件的光电转换效率可以达到20.58％和20.53％。(The invention relates to the technical field of novel hole transport materials in perovskite solar cells, in particular to a hole transport material and application thereof in perovskite solar cells, wherein spirobifluorene, biscarbazole and spiro [ fluorene-9.9' -xanthene are respectively used as the hole transport material]As central nucleus, containing CF 3 The diphenylamine derivative modified by the derivative is a peripheral end-capping group, and a hole transport material for preparing the high-efficiency and stable perovskite solar cell is designed and synthesized. Which is used for preparingThe hole transport material of the perovskite solar cell is prepared efficiently and stably, the preparation process is simple, the raw materials are easy to obtain, the price is low, and the method is very suitable for industrial production. The prepared battery has lower HOMO energy level, and is beneficial to improving the open-circuit voltage of a device; the good hydrophobicity is favorable for improving the stability of the device; higher hole mobility. The photoelectric conversion efficiency of the device can reach 20.58% and 20.53%.)

1. A hole transport material having a structure according to formula I:

wherein R is CF₃The Core group is a compound containing aromatic rings with twisted structures.

2. The hole transport material according to claim 1, wherein: said R is preferably-CF₃、-OCH₂CF₃or-OCH₂CH₂CF₃。

3. The hole transport material according to claim 1, wherein: the Core group is represented by one of the following general formulae (II), (III), (IV):

4. a hole transport material according to claim 1, wherein the compound is preferably:

5. a hole transport material according to claim 4, wherein the compound represented by the formula (V) is prepared according to the following reaction scheme:

6. the hole transport material of claim 5, wherein:

synthesis of the intermediate a: at room temperature, dissolving a bromine-containing substituted spirobifluorene derivative, p-anisidine and sodium tert-butoxide in dry toluene respectively, heating a reaction system to 80 ℃ in a nitrogen atmosphere, and adding tri-tert-butylphosphine tetrafluoroborate and tris-dibenzylideneacetone dipalladium; the whole reaction system is subjected to reflux reaction for 10 hours at the temperature of 120 ℃; after the reaction is finished, cooling the reaction product to room temperature; adding deionized water into the reaction solution, extracting with ethyl acetate, drying the organic phase obtained after extraction with anhydrous magnesium sulfate, and filtering; removing the solvent to obtain a crude product; separating and purifying the crude product by using a chromatographic column to obtain an intermediate A;

Synthesis of the compound V: intermediate A, CF-containing₃Respectively dissolving a bromo-compound of the group and sodium tert-butoxide in toluene, heating the reaction system to 80 ℃ in a nitrogen atmosphere, and adding tri-tert-butylphosphine tetrafluoroborate and tris-dibenzylideneacetone dipalladium; the whole reaction system is subjected to reflux reaction for 10 hours at the temperature of 120 ℃; after the reaction is finished, cooling the reaction product to room temperature; adding deionized water into the reaction solution, extracting with ethyl acetate, drying the organic phase obtained after extraction with anhydrous magnesium sulfate, and filtering; removing the solvent to obtain a crude product; the crude product was isolated and purified using a chromatography column to give compound V.

7. A hole transport material according to claim 4, wherein the compound represented by the formula (VI) is prepared according to the following reaction scheme:

8. the hole transport material of claim 7, wherein:

synthesis of the intermediate B: at room temperature, dissolving a bromine-containing substituted dicarbazole derivative, p-anisidine and sodium tert-butoxide in dry toluene respectively; heating the reaction system to 80 ℃ in the nitrogen atmosphere, and adding tri-tert-butylphosphine tetrafluoroborate and tris-dibenzylidene acetone dipalladium; the whole reaction system is subjected to reflux reaction for 10 hours at the temperature of 120 ℃; after the reaction is finished, cooling the reaction product to room temperature; adding deionized water into the reaction solution, extracting with ethyl acetate, drying the organic phase obtained after extraction with anhydrous magnesium sulfate, and filtering; removing the solvent to obtain a crude product; separating and purifying the crude product by using a chromatographic column to obtain an intermediate B;

Synthesis of the compound VI: intermediate B, containing CF₃The bromo compound of the group, sodium tert-butoxide are dissolved in toluene respectively in N₂Heating the reaction system to 80 ℃ in the atmosphere, and adding tri-tert-butylphosphine tetrafluoroborate and tris-dibenzylidene acetone dipalladium; the whole reaction system is subjected to reflux reaction for 10 hours at the temperature of 120 ℃; after the reaction is finished, cooling the reaction product to room temperature; adding deionized water into the reaction solution, extracting with ethyl acetate, drying the organic phase obtained after extraction with anhydrous magnesium sulfate, and filtering; removing the solvent to obtain a crude product; the crude product was isolated and purified using a chromatography column to give compound VI.

9. The application of the hole transport material in the perovskite solar cell is characterized in that the preparation method specifically comprises the following steps:

s1, preparing a conductive glass substrate: firstly, cleaning pollutants such as dust and the like attached to the surface of a conductive glass substrate by using a detergent, and then sequentially carrying out ultrasonic cleaning for 18min by using ultrapure water, acetone and isopropanol to remove organic pollutants; the cleaned conductive glass substrate is dried by nitrogen, and then is subjected to ultraviolet-ozone treatment for 15min, so that the surface of the conductive glass substrate is clean and clean;

s2, preparing a compact titanium dioxide layer: putting the conductive glass treated in the S1 into a titanium tetrachloride solution, placing the conductive glass in an oven at the temperature of 70 ℃ for 1h, and depositing a titanium dioxide layer with the thickness of about 40nm on a conductive glass substrate; then washing the glass substrate with ultrapure water for 2min, washing off loose titanium dioxide, blow-drying with nitrogen, and then annealing on a heating plate at 185 ℃ for 30 min;

S3, preparing a perovskite layer: carrying out ultraviolet-ozone treatment on the conductive glass substrate deposited with the compact titanium dioxide layer in the S2 for 15min again; uniformly mixing 1H-imidazol-1-yl (2-methyl-3-furyl) methanone, methyl amine iodide and lead iodide, and adding anhydrous N, N-dimethylformamide with a volume ratio of 4: 1: anhydrous dimethyl sulfoxide, and preparing a precursor solution of perovskite; the preparation of the perovskite layer is completed by a one-step spin coating method, firstly, the perovskite precursor solution is uniformly dripped on the compact titanium dioxide layer, the spin coating is carried out for 5s at the speed of 1000rpm, and then the spin coating is carried out for 45s at the speed of 4000 rpm; quickly dripping 150mL of chlorobenzene solution on the surface of the perovskite when spin-coating is carried out for 10s at the speed of 4000 rpm; after the spin coating is finished, the conductive glass substrate coated with the perovskite is placed on a heating plate at 150 ℃ for annealing for 30 min;

s4, preparing a hole transport layer: respectively dissolving the compound as defined in any one of claims 1 to 4 or the compound prepared as defined in any one of claims 5 to 8 in a chlorobenzene solution with a mass concentration of 90mg/mL, sequentially adding 4-tert-butylpyridine and lithium bis (trifluoromethanesulfonylimide) thereto, and subsequently spin-coating the surface of the perovskite layer of the conductive glass substrate at 4000rpm in S3 for 20S to prepare a hole transport layer;

S5, preparing a metal electrode: the gold electrode is deposited on the surface of the hole transport layer by thermal evaporation, and the thickness of the gold electrode is 100 nm.

10. Use of a hole transport material according to claim 9 in a perovskite solar cell, wherein: the molar ratio of the 1H-imidazole-1-yl (2-methyl-3-furyl) ketone to the methyl amine iodide to the lead iodide is 17: 3: 20; in the step S4, the adding amount of 4-tert-butylpyridine in each milliliter of chlorobenzene solution is 36 muL, and the adding amount of lithium bis (trifluoromethanesulfonyl) imide is 22 muL.

Technical Field

The invention relates to the technical field of novel hole transport materials in perovskite solar cells, in particular to a hole transport material and application thereof in perovskite solar cells.

Background

Perovskite solar cells are superior from the first scientific assumption to the photovoltaic field. Among them, organic-inorganic hybrid perovskite solar cells are attracting attention because of low cost, simple preparation, light weight, and suitability for mass production. Meanwhile, the efficiency of the perovskite solar cell is improved at a high speed. In the last decades, the authentication efficiency of the perovskite solar cell is improved from 3.8% to 25.2%, and the perovskite solar cell is expected to be a substitute of the first-generation silicon-based solar cell and has a potential commercial application prospect. The device structure of the perovskite solar cell is mainly three types: mesoscopic structures, planar structures (n-i-p) and trans-planar structures (p-i-n). In all three device structures, the hole transport layer plays a role in extracting and transporting holes and blocking the perovskite layer from being directly contacted with the external environment (such as moisture, oxygen and the like). Therefore, the performance and stability of the perovskite solar cell are directly influenced by the performance of the hole transport material. Hole transport materials are divided into three major classes according to the type of material: inorganic hole transport materials, polymeric hole transport materials, and organic small molecule hole transport materials. The inorganic hole transport material has many surface defects, and a part of perovskite can be dissolved by a solvent used in deposition, so that the stability of the device is reduced. The polymer hole transport material is difficult to purify, low in solubility and difficult to determine the molecular weight. The organic micromolecule hole transport material has simple synthesis, low cost and easy performance regulation and control, and becomes a hotspot of research of people. Among them, commercial 2,2',7,7' -tetrakis [ N, N-bis (4-methoxyphenyl) amino ] -9,9' -spirobifluorene (Spiro-OMeTAD) is complicated to synthesize, expensive, and has low hole mobility, thus preventing its large-scale application. Therefore, the development of low-cost and efficient organic small-molecule hole transport materials plays a crucial role in promoting the perovskite solar cell to achieve commercial application.

The high-performance hole transport material should have the characteristics of simple synthesis, low price, energy level matched with the perovskite material, good thermal stability and chemical stability, particularly good hydrophobicity, high hole mobility and the like. Previous studies have shown that bis-carbazoles obtained by linking two carbazole units via an "N-N" bond have a highly vertically distorted steric structure, which is relatively similar to that of spirobifluorenes. However, the biscarbazole is simple to synthesize and low in price, and is expected to replace spirobifluorene in the development of hole transport materials later. In order to improve the properties of the molecules, it is desirable to introduce more groups having specific functions into the molecular structure. Thus, the present invention utilizes trifluoromethyl (CF)₃) Good hydrophobicity and certain electron withdrawing ability, and CF₃The derivatives are introduced into diphenylamine derivatives to be used as end capping groups to synthesize a new class of compounds, and the compounds are used as hole transport materials to prepare high-performance perovskite solar cells.

The invention relates to spirobifluorene, dicarbazole and spiro [ fluorene-9, 9' -xanthene]Respectively as central nucleus, CF₃The diphenylamine derivative modified by the derivative is a peripheral end-capping group, and a hole transport material for preparing the high-efficiency and stable perovskite solar cell is designed and synthesized.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention respectively uses spirobifluorene, dicarbazole and spiro [ fluorene-9, 9' -xanthene]As central nucleus, containing CF₃The diphenylamine derivative modified by the derivative is a peripheral end-capping group, and a hole transport material for preparing the high-efficiency and stable perovskite solar cell is designed and synthesized. The material has the characteristics of good hydrophobicity and high hole mobility, and can be used as a hole transport material to prepare a high-efficiency and stable perovskite solar cell.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a hole transport material having the structure of formula I:

wherein R is CF₃The Core group is a compound containing aromatic rings with twisted structures.

Further, the R is preferably-CF₃、-OCH₂CF₃or-OCH₂CH₂CF₃。

Further, the Core group may be represented by one of the following general formulae (II), (III), (IV):

further, the compound is preferably:

further, the compound represented by the formula (V) is prepared according to the following reaction scheme:

further, synthesis of the intermediate A: at room temperature, the bromine-containing substituted spirobifluorene derivative, p-anisidine and sodium tert-butoxide are respectively dissolved in dry toluene and then the mixture is subjected to condensation polymerization ₂Heating the reaction system to 80 ℃ in the atmosphere, and adding tri-tert-butylphosphine tetrafluoroborate and tris-dibenzylidene acetone dipalladium; the whole reaction system is subjected to reflux reaction for 10 hours at the temperature of 120 ℃; after the reaction is finished, cooling the reaction product to room temperature; adding deionized water into the reaction solution, extracting with ethyl acetate, drying the organic phase obtained after extraction with anhydrous magnesium sulfate, and filtering; removing the solvent to obtain a crude product; separating and purifying the crude product by using a chromatographic column to obtain an intermediate A;

synthesis of the compound V: intermediate A, CF-containing₃The bromo compound of the group, sodium tert-butoxide are dissolved in toluene respectively in N₂Heating the reaction system to 80 ℃ in the atmosphere, and adding tri-tert-butylphosphine tetrafluoroborate and tris-dibenzylidene acetone dipalladium; the whole reaction system is subjected to reflux reaction for 10 hours at the temperature of 120 ℃; after the reaction is finished, cooling the reaction product to room temperature; adding deionized water into the reaction solution, extracting with ethyl acetate, drying the organic phase obtained after extraction with anhydrous magnesium sulfate, and filtering; the solvent was removed to give the crude product. The crude product was isolated and purified using a chromatography column to give compound V.

Further, the compound represented by the formula (VI) is prepared according to the following reaction scheme:

Further, synthesis of the intermediate B: at room temperature, dissolving a bromine-containing substituted dicarbazole derivative, p-anisidine and sodium tert-butoxide in dry toluene respectively; in N₂Heating the reaction system to 80 ℃ in the atmosphere, and adding tri-tert-butylphosphine tetrafluoroborate and tris-dibenzylidene acetone dipalladium; the whole reaction system is subjected to reflux reaction for 10 hours at the temperature of 120 ℃; after the reaction is finished, cooling the reaction product to room temperature; deionized water was then added to the reaction solution and extracted with ethyl acetate, and the organic phase obtained after extraction was dried over anhydrous magnesium sulfate and filtered(ii) a The solvent was removed to give the crude product. Separating and purifying the crude product by using a chromatographic column to obtain an intermediate B;

synthesis of the compound VI: intermediate B, containing CF₃The bromo compound of the group, sodium tert-butoxide are dissolved in toluene respectively in N₂Heating the reaction system to 80 ℃ in the atmosphere, and adding tri-tert-butylphosphine tetrafluoroborate and tris-dibenzylidene acetone dipalladium; the whole reaction system is subjected to reflux reaction for 10 hours at the temperature of 120 ℃; after the reaction was complete, it was cooled to room temperature. Adding deionized water into the reaction solution, extracting with ethyl acetate, drying the organic phase obtained after extraction with anhydrous magnesium sulfate, and filtering; removing the solvent to obtain a crude product; the crude product was isolated and purified using a chromatography column to give compound VI.

The application of the hole transport material in the perovskite solar cell specifically comprises the following steps:

s1, preparing a conductive glass substrate: firstly, cleaning pollutants such as dust and the like attached to the surface of a conductive glass substrate by using a detergent, and then sequentially carrying out ultrasonic cleaning for 18min by using ultrapure water, acetone and isopropanol to remove organic pollutants; the cleaned conductive glass substrate is dried by nitrogen, and then is subjected to ultraviolet-ozone treatment for 15min, so that the surface of the conductive glass substrate is clean and clean;

s2, preparing a compact titanium dioxide layer: putting the conductive glass treated in the S1 into a titanium tetrachloride solution, placing the conductive glass in an oven at the temperature of 70 ℃ for 1h, and depositing a titanium dioxide layer with the thickness of about 40nm on a conductive glass substrate; then washing the glass substrate with ultrapure water for 2min, washing off loose titanium dioxide, blow-drying with nitrogen, and then annealing on a heating plate at 185 ℃ for 30 min;

s3, preparing a perovskite layer: carrying out ultraviolet-ozone treatment on the conductive glass substrate deposited with the compact titanium dioxide layer in the S2 for 15min again; uniformly mixing 1H-imidazol-1-yl (2-methyl-3-furyl) methanone, methyl amine iodide and lead iodide, and adding anhydrous N, N-dimethylformamide with a volume ratio of 4: 1: anhydrous dimethyl sulfoxide, and preparing a precursor solution of perovskite; the preparation of the perovskite layer is completed by a one-step spin coating method, firstly, the perovskite precursor solution is uniformly dripped on the compact titanium dioxide layer, the spin coating is carried out for 5s at the speed of 1000rpm, and then the spin coating is carried out for 45s at the speed of 4000 rpm; quickly dripping 150mL of chlorobenzene solution on the surface of the perovskite when spin-coating is carried out for 10s at the speed of 4000 rpm; after the spin coating is finished, the conductive glass substrate coated with the perovskite is placed on a heating plate at 150 ℃ for annealing for 30 min;

S4, preparing a hole transport layer: respectively dissolving the compound or the compound prepared by the method in chlorobenzene solution with the mass concentration of 90mg/mL, sequentially adding 4-tert-butylpyridine and lithium bis (trifluoromethanesulfonyl) imide, and spin-coating the surface of the perovskite layer of the conductive glass substrate at the speed of 4000rpm in S3 for 20S to prepare a hole transport layer;

s5, preparing a metal electrode: the gold electrode is deposited on the surface of the hole transport layer by thermal evaporation, and the thickness of the gold electrode is 100 nm.

Further, the molar ratio of the 1H-imidazol-1-yl (2-methyl-3-furyl) methanone to the methyl amine iodide to the lead iodide is 17: 3: 20; in the step S4, the adding amount of 4-tert-butylpyridine in each milliliter of chlorobenzene solution is 36 muL, and the adding amount of lithium bis (trifluoromethanesulfonyl) imide is 22 muL.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a hole transport material and application thereof in perovskite solar cells, wherein spirobifluorene, biscarbazole and spiro [ fluorene-9.9' -xanthene are respectively used as the hole transport material]As central nucleus, containing CF₃The diphenylamine derivative modified by the derivative is a peripheral end capping group, wherein spirobifluorene, dicarbazole and spiro [ fluorene-9.9' -xanthene]All have highly distorted spatial structures, which is beneficial to reducing the aggregation of molecules, improving the solubility, improving the film forming property and improving the film quality. According to the invention, functional groups containing trifluoromethyl are introduced to the periphery of the hole transport material, so that the hole transport material has good hydrophobic property and high hole mobility; the method is used for preparing the hole transport material of the high-efficiency and stable perovskite solar cell, has simple preparation process, easily obtained raw materials and low cost, and is very suitable for industrial production. The prepared battery has lower HOMO energy level, and is beneficial to improving the open-circuit voltage of a device; good hydrophobicity The stability of the device is improved; higher hole mobility. The photoelectric conversion efficiency of the device can reach more than 20%. Meanwhile, the efficiency of the device which is not packaged can still maintain more than 90% of the initial efficiency after the device is placed for 15 days under the condition that the air humidity is 60%, and the device has good stability.

Drawings

FIG. 1 is a cyclic voltammogram of Compound V;

FIG. 2 is a cyclic voltammogram of Compound VI;

FIG. 3 is the hydrophobic nature of Compound V;

FIG. 4 is the hydrophobic nature of Compound VI;

FIG. 5 shows the hole transport properties of Compound V;

FIG. 6 is the hole transport properties of Compound VI;

FIG. 7 is a device structure diagram of a perovskite solar cell prepared by using a compound as a hole transport material;

FIG. 8 is a J-V characteristic curve for a perovskite solar cell of Compound V;

FIG. 9 is a J-V characteristic curve for a compound VI perovskite solar cell;

FIG. 10 is a perovskite solar cell stability test curve for Compound V;

FIG. 11 is a perovskite solar cell stability test curve of Compound VI;

FIG. 12 is a TGA test profile of Compound VI;

FIG. 13 is a DSC chart of Compound VI.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A hole transport material having the structure of formula I:

wherein R is CF₃The Core group is a compound containing aromatic rings with twisted structures.

Said R is preferably-CF₃、-OCH₂CF₃or-OCH₂CH₂CF₃。

The Core group is represented by one of the following general formulae (II), (III), (IV):

the compound is preferably:

taking spirobifluorene as a central nucleus, respectively introducing a conjugated group containing F and a non-conjugated group containing F substituted 4,4' -dimethoxydiphenylamine derivative to 3,3',6,6' active sites of the spirobifluorene, and preparing a compound shown as a formula (V) according to the following reaction route:

synthesis of intermediate a: 2,2',7,7' -tetrabromo-9, 9' -spirobifluorene (2g,3.16mmol), p-anisidine (3.13g,25.28mmol), and sodium tert-butoxide (2.43g,25.28mmol) were dissolved in 40mL of dry toluene at room temperature, respectively. In N₂The reaction was warmed to 80 ℃ under an atmosphere, and dibenzylideneacetone dipalladium (868.12mg,0.948mmol) and tri-tert-butylphosphine tetrafluoroborate (550mg,1.896mmol) were added. The whole reaction system is refluxed for 10 hours at 120 ℃. After the reaction was complete, it was cooled to room temperature. Deionized water was then added to the reaction solution and extracted with ethyl acetate, and the organic phase obtained after extraction was dried over anhydrous magnesium sulfate and filtered. Removing the solvent Obtaining a crude product after the reaction. The crude product was isolated and purified using a chromatography column to afford intermediate a as a brown powder (2,48g, 70% yield).¹HNMR(600MHz,DMSO):＝7.70(s,4H),7.51(d,J＝8.3Hz,4H),6.91–6.87(m,13H),6.76(d,J＝9.0Hz,8H),6.18(d,J＝2.2Hz,4H),3.64(s,12H).MALDI-TOF:m/z[M]+cacld.C₅₃H₄₄N₄O₄,800.3363；found:800.3360。

Synthesis of compound V: intermediate A (1.5g,1.91mmmol), 1-bromo-4- (2,2, 2-trifluoro-ethoxy) benzene (2.92g,11.46mmol), sodium tert-butoxide (1.47g,15.28mmol) were dissolved in 30mL of toluene, respectively. In N₂The reaction system was warmed to 80 ℃ under an atmosphere, and tris (dibenzylideneacetone) dipalladium (524.72mg,0.573mmol) and tris (tert-butylphosphine) tetrafluoroborate (332.3mg,1.146mmol) were added. The whole reaction system is refluxed for 10 hours at 120 ℃. After the reaction was complete, it was cooled to room temperature. Deionized water was then added to the reaction solution and extracted with ethyl acetate, and the organic phase obtained after extraction was dried over anhydrous magnesium sulfate and filtered. The solvent was removed to give the crude product. The crude product was isolated and purified using a chromatography column to give compound V as a yellow powder (2.06g, 72% yield).¹HNMR(600MHz,DMSO):＝7.51(dd,J＝8.2,3.6Hz,4H),6.92(d,J＝9.0Hz,8H),6.88–6.82(m,24H),6.73(dd,J＝8.3,2.0Hz,4H),6.21(d,J＝1.9Hz,4H),4.68(q,J＝8.8Hz,8H),3.72(s,12H).¹³CNMR(101MHz,DMSO):＝156.01；153.03；149.85；147.46；142.41；140.62；134.71；132.81；126.49；125.84；125.33；123.08；121.77；120.89；117.66；116.37；115.24；65.54；65.20；55.62；40.59；40.38；40.17；39.97；39.79；39.65；39.34.MALDI-TOF:m/z[M]+cacld.C₈₅H₆₄F₁₂N₄O₈,1496.4533；found:1496.4531。

Taking dicarbazole as a central core, respectively introducing F-containing conjugated groups and F-containing non-conjugated group-substituted 4,4' -dimethoxydiphenylamine derivatives into 2,2',7 and 7' active sites of the dicarbazole, and preparing a compound shown in a formula (VI) according to the following reaction route:

Synthesis of intermediate B: bromine-containing substituted biscarbazole (1.5g,2.31mmol), p-anisidine (2.28g,18.52mmol), and sodium tert-butoxide (1.78g,18.52mmol) were dissolved in 30mL of toluene at room temperature, respectively. In N₂The reaction system was warmed to 80 ℃ under an atmosphere, and dibenzylideneacetone dipalladium (639.2mg,0.693mmol) and tri-tert-butylphosphine tetrafluoroborate (402mg,1.386mmol) were added. The whole reaction system is refluxed for 10 hours at 120 ℃. After the reaction was complete, it was cooled to room temperature. Deionized water was then added to the reaction solution and extracted with ethyl acetate, and the organic phase obtained after extraction was dried over anhydrous magnesium sulfate and filtered. The solvent was removed to give the crude product. The crude product was isolated and purified using a chromatography column to afford intermediate B as a brown powder (1.32g, 70% yield). 1HNMR (600MHz, DMSO): 7.95(s,4H),7.84(d, J ═ 8.4Hz,4H),6.97(d, J ═ 8.9Hz,8H),6.91(dd, J ═ 8.5,1.9Hz,4H),6.77(d, J ═ 8.9Hz,8H),6.35(d, J ═ 1.9Hz,4H),3.66(s,12H), 13CNMR (101MHz, DMSO): 154.21; 143.77, respectively; 141.15, respectively; 136.62, respectively; 120.67, respectively; 120.46, respectively; 120.37, respectively; 114.94, respectively; 114.72, respectively; 109.92, respectively; 95.03, respectively; 55.61; 40.60; 40.39, respectively; 40.08 of; 39.97; 39.87; 39.56; MALDI-TOF M/z [ M ] ]+cacld.C₅₂H₄₄N₆O₄,816.3424；found:816.3422。

Synthesis of Compound VI: intermediate B (1.3g,1.59mmmol), 1-bromo-4- (2,2, 2-trifluoro-ethoxy) benzene (2.43g,9.55mmol), sodium tert-butoxide (1.22g,12,72mmol) were dissolved in 12mL dry toluene, respectively. In N₂The reaction system was warmed to 80 ℃ under an atmosphere, and tris (dibenzylideneacetone) dipalladium (436.8mg,0.477mmol) and tris (tert-butylphosphine) tetrafluoroborate (276.7mg,0.954mmol) were added. The whole reaction system is refluxed for 10 hours at 120 ℃. After the reaction was complete, it was cooled to room temperature. Deionized water was then added to the reaction solution and extracted with ethyl acetate, and the organic phase obtained after extraction was dried over anhydrous magnesium sulfate and filtered. The solvent was removed to give the crude product. The crude product was isolated and purified using a chromatography column to give compound VI as a yellow powder (1.64g, 68% yield). 1HNMR (600MHz, DMSO): 7.80(d, J ═ 8.5Hz,4H),6.93-6.89(m,24H),6.83-6.80(m,8H),6.70(dd,J＝8.5,2.0Hz,4H),6.14(d,J＝2.1Hz,4H),4.67(q,J＝8.9Hz,8H),3.70(s,12H).13CNMR(101MHz,DMSO):＝156.20；153.29；146.92；142.28；141.19；140.48；126.92；125.91；123.07；121.34；116.34；116.34；115.62；115.28；100.23；65.86；65.53；65.19；64.85；55.62；40.59；40.39；40.18；39.97；39.76；39.55；39.34.MALDI-TOF:m/z[M]+cacld.C₈₄H₆₄F₁₂N₆O₈,1512.4594；found:1512.4590。

The reaction route for preparing the hole transport material by taking spiro [ fluorene-9.9' -xanthene ] as a central core is as follows to obtain a compound VII, and the performance of the compound VII is similar to that of a compound V and a compound VI and the application principle of the compound VI in the perovskite solar cell.

Characterization of properties of compound V and compound VI:

(1) measuring photophysical properties;

A chlorobenzene solution of compound V and compound VI was prepared, and the absorption spectrum of the compound solution was measured by Hitachi corporation U-3900, USA. Measuring that the absorption peaks of the compound V in the solution state are located at 307nm and 387nm, and the optical band gap is 2.877 eV; while the absorption peak of compound VI is at 389.5nm and the optical band gap is 2.95 eV.

(2) Determination of electrochemical properties:

the electrochemical properties of the compounds were determined using electrochemical Cyclic Voltammetry (CV) with the experimental instrument autolab pgstat30 electrochemical workstation, switzerland, which employs a three-electrode system. The solvent used in the test was typically chlorobenzene and the electrolyte was tetrabutylammonium hexafluorophosphate (Bu)₄NPF₆) The concentration is 0.1M; the test environment required nitrogen protection. The instrument scan rate was 100mVS^-1The reference substance is ferrocene, and the HOMO energy level and the LUMO energy level of the material are jointly calculated by measuring the voltage of a first oxidation peak and the position of an absorption edge in an ultraviolet absorption spectrum respectively. Determination of HOMO energy of Compound V and Compound VIThe levels are-5.168 eV and-5.20 eV, respectively, and the LUMO levels are-2.291 eV and-2.25 eV, respectively.

(3) Determination of thermodynamic stability:

thermogravimetric (TGA) testing: the TGA spectrum test uses a German relaxation-resistant 209F3 thermogravimetric instrument, under the condition of nitrogen protection, the temperature rising rate is 10 ℃/min, the flow rate of protective gas flow nitrogen is 30mL/min, and the weight of the material is changed until the constant weight state is reached.

Differential Scanning Calorimetry (DSC) test: DSC atlas test uses a DSCQ2000 differential thermal instrument of American TA company, under the condition of nitrogen protection, the temperature rising rate is 10 ℃/min, and the temperature reducing rate is 20 ℃/min.

The thermal decomposition temperatures of compound V and compound VI were 220 ℃ and 363 ℃ and the glass transition temperatures were 78 ℃ and 183 ℃ respectively, as determined by DSC measurement and TGA measurement. Fig. 12 is a TGA test chart of compound VI, where the thermal decomposition temperature of compound VI is 363 ℃, which is beneficial to maintaining the structural stability during the device manufacturing process and also beneficial to improving the stability of the device; FIG. 13 is a DSC of compound VI, which has a glass transition temperature of 183 ℃. DSC test and TGA test show that the prepared compound has good thermal stability and is beneficial to improving the stability of devices.

(4) Measurement of hole mobility:

the hole mobility of the compound is tested by using a space charge limited current method (SCLC), the hole mobility test represents the hole transport capability of the compound, and the higher the hole mobility is, the better the hole transport capability is; FIG. 5 is a schematic diagram of the hole transporting property of compound V, and FIG. 6 is a schematic diagram of the hole transporting property of compound VI; the hole mobility of the compound V and the hole mobility of the compound VI are respectively 2.31 multiplied by 10 ^-4cm²V^-1S^-1And 1.71X 10^-4cm²V^-1S^-1。

(5) Determination of hydrophobicity:

the water contact angle of the compound can be obtained through a hydrophobicity test, the larger the water contact angle is, the better the hydrophobicity is, the moisture can be effectively prevented from being directly contacted with the perovskite, and the stability of the device can be improved. FIG. 3 is a water contact angle test for compound V; figure 4 is a water contact angle test for compound VI.

Compound V and compound VI performance characteristics are shown in the following table:

and respectively applying the compound V and the compound VI as hole transport materials to the doped perovskite solar cell. The solar cell device mainly includes: FTO glass substrate, dense TiO₂A layer, a perovskite layer, a hole transport layer and a metal electrode. Wherein the TiO is dense₂The layer serves as an electron transport layer and the perovskite layer serves as a light absorption layer. The structure of which is shown in fig. 7.

The method for preparing the perovskite solar cell by using the hole transport material comprises the following steps:

(1) preparing an FTO glass substrate: firstly, cleaning pollutants such as dust and the like attached to the surface of the FTO glass substrate by using a detergent, and then sequentially carrying out ultrasonic cleaning for 18min by using ultrapure water, acetone and isopropanol to remove organic pollutants. N for cleaned FTO glass substrate₂Blow-drying, and then carrying out ultraviolet-ozone treatment for 15min to ensure that the surface is clean and clean.

(2) Preparation of compact TiO₂Layer (b): placing the treated FTO glass into titanium tetrachloride solution, placing in an oven at 70 deg.C for 1h, and depositing on FTO glass substrate to obtain TiO with thickness of about 40nm₂And (3) a layer. Washing the glass substrate with ultrapure water for 2min to remove loose TiO₂Reuse of N₂It was blow-dried and then placed on a hot plate at 185 ℃ for annealing for 30 min.

(3) Preparing a perovskite layer: prior to the preparation of the perovskite layer, it is necessary to apply to the previously prepared FTO glass substrate/TiO₂The UV-ozone treatment was performed again for 15 min. Dissolving FAI (0.85mmol), MAI (0.15mmol) and PbI respectively in a volume ratio of 4:1₂(1mmol) are mixed well and then anhydrous DMF is added in a volume ratio of 4: 1: anhydrous DMSO, and preparing a precursor solution of the perovskite. The preparation of the perovskite layer is completed by a one-step spin coating method, and the perovskite precursor solution is firstly preparedUniformly dropwise adding the mixture to the dense TiO₂Above, spin-coat was carried out at 1000rpm for 5s and at 4000rpm for 45 s. 150mL of chlorobenzene solution was quickly added dropwise to the perovskite surface while spin coating at 4000rpm for 10 s. After the spin coating was completed, the prepared sample was annealed on a heating plate at 150 ℃ for 30 min.

(4) Preparing a hole transport layer: compound V and compound VI were dissolved in chlorobenzene solutions (90mg/mL), respectively, and 4-tert-butylpyridine (36. mu. LmL) was added thereto in this order ^-1) And lithium bis (trifluoromethanesulfonylimide) (22. mu. LmL)^-1) Subsequently, the perovskite surface was spin-coated for 20s at 4000 rpm.

(5) And preparing a metal electrode. The gold electrode was deposited on the surface of the HTL by thermal evaporation deposition to 100 nm. PSCs with formal structures can be obtained through the preparation process, and the effective area of the PSCs is 9mm²。

The test method of the battery comprises the following steps:

(1) determination of electrochemical Properties of Compounds: the test environment is room temperature, tetrabutyl ammonium perchlorate (0.1M) is used as electrolyte, Ag/Ag⁺As reference electrode, calomel electrode as working electrode, platinum electrode (Pt) as counter electrode, and Fc/Fc⁺The reference electrode was calibrated as an internal reference and the scan rate was chosen to be 100 mV/S. The cyclic voltammetry curve of the compound V shown in figure 1 and the cyclic voltammetry curve of the compound VI shown in figure 2 are obtained through electrochemical tests, the positions of the initial oxidation peak of the compound and the oxidation peak of ferrocene can be seen in the curves, and then the HOMO and LUMO energy levels of the material are calculated by combining with the ultraviolet-visible absorption spectrum.

E_LUMO＝E_HOMO+E_g(2)

In the formulaIs the initial oxidation peak of the compound and is,is the oxidation peak of ferrocene; then calculating HOMO energy levels of compound V and compound VI according to formula (1), and calculating LUMO energy levels of compound V and compound VI according to formulas (2) and (3), wherein E _gAnd lambda is the wavelength corresponding to the position of the edge of the absorption band in the ultraviolet-visible absorption spectrum of the solution.

(2) Solar cell performance measurement: the photovoltaic performance test of the perovskite solar cell based on the compound V and the compound VI is to test a current density-voltage characteristic curve, namely a J-V curve, under standard solar radiation. The J-V characteristics of the perovskite solar cell based on the compound V and the compound VI were tested by using a solar simulator (am1.5g, SAN-eimectricxides-40S 2-CE), as shown in fig. 8, which is a J-V characteristic curve of the perovskite solar cell of the compound V, and as shown in fig. 9, which is a J-V characteristic curve of the perovskite solar cell of the compound VI; four performance parameters of the battery, such as open-circuit voltage, short-circuit current, filling factor and photoelectric conversion efficiency can be obtained through testing of a current density-voltage curve, and the good and bad photovoltaic performance of the battery can be seen through the four performance parameters; and calibrated by standard silicon-based solar cells.

(3) And (3) testing the stability of the solar cell, wherein the graph in fig. 10 is a stability test curve of the perovskite solar cell of the compound V, and the graph in fig. 11 is a stability test curve of the perovskite solar cell of the compound VI. It was found by testing that the device efficiencies maintained 91.5% and 93% of the initial efficiencies after 15 days of exposure of the unpackaged compound V-based perovskite solar cell device and the compound VI-based perovskite solar cell device to 60% air humidity, respectively. This indicates that both battery devices have good stability. These experimental data show that the device efficiency can still maintain more than 90% of the initial efficiency after 15 days of non-encapsulated perovskite solar cell devices based on two preferred compounds under conditions of 60% air humidity.

Although only the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art, and all changes are encompassed in the scope of the present invention.