Perovskite solar cell and preparation method thereof

Abstract

The invention provides a perovskite solar cell and a preparation method thereof. The perovskite solar cell comprises a substrate, a first electrode, a first carrier transport layer, a perovskite light absorption layer, a second carrier transport layer and a second electrode which are sequentially stacked, and the first carrier transport layer and the second carrier transport layer are independently selected from a hole transport layer or an electron transport layer. The material of the hole transport layer comprises an organic compound, and the organic compound comprises a dibenzothiophene sulfone compound. The dibenzothiophene sulfone compound with the specific structure is applied to a perovskite solar cell system, and the photoelectric conversion efficiency of a perovskite solar cell can be remarkably improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of perovskite solar cell materials, and particularly relates to a perovskite solar cell and a preparation method thereof. BACKGROUND

[0002] Compared with traditional fossil energy, solar energy has the advantages of inexhaustibility and wide distribution on the earth. As long as there is light, photovoltaic power generation systems can be used anywhere without being restricted by factors such as region and altitude. In order to more efficiently utilize solar energy, researchers have developed solar cell energy storage devices to directly convert light energy into electrical energy through photoelectric effect or photochemical effect. Silicon solar cells are one of the earliest photovoltaic cells. Since the first silicon solar cell was successfully developed by Bell researchers in the United States in 1954, silicon solar cell technology has made significant progress. At present, commercial solar cells are mainly crystalline silicon solar cells, but the energy conversion efficiency has reached more than 20%. However, due to the high hardness and melting point of crystalline silicon, the processing cost is increased, and therefore the large-scale development of crystalline silicon solar cells is further limited.

[0003] In comparison, organic polymer solar cells or perovskite solar cells have the advantages of low production cost, easy processing (such as spin coating, inkjet printing, etc.), and easy structure adjustment. In addition, they are light in weight, flexible, and have good film-forming properties, so both of the above-mentioned solar cells are suitable for manufacturing large-area and flexible solar cells. Although the conversion efficiency of organic polymer solar cells and perovskite solar cells is currently lower than that of silicon solar cells, there is still a lot of room for improvement.

[0004] In order to further improve the photoelectric conversion efficiency of solar cells, researchers have adopted many technical means. However, most of the current technical solutions mainly solve the above problems by optimizing the device structure or interface engineering, but there are not many choices for the type of hole transport layer material. Hole transport photoelectric material is a special semiconductor material, which is characterized by high-efficiency hole transport. In the photoelectric conversion process, the transport efficiency of holes determines the performance of the photoelectric material. Compared with inorganic hole transport materials, organic hole transport materials have the advantages of easy structure adjustment and easy processing, thereby improving the transport efficiency of holes. Although organic hole transport materials have many advantages in solar cells, the existing organic hole transport materials disclosed by the prior art still have problems such as dissolution or dependence on additives.

[0005] Therefore, in the field, there is an urgent need to develop a multifunctional organic hole transport material to develop a perovskite solar cell with high efficiency and high stability. SUMMARY

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a perovskite solar cell and its fabrication method. The dibenzothiophene sulfone compounds with specific structures provided by the present invention, when used in perovskite solar cell systems, can significantly improve the photoelectric conversion efficiency of perovskite solar cells.

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

[0008] In a first aspect, the present invention provides a perovskite solar cell, the perovskite solar cell comprising a substrate, a first electrode, a first carrier transport layer, a perovskite light-absorbing layer, a second carrier transport layer, and a second electrode stacked sequentially, wherein the first carrier transport layer and the second carrier transport layer are each independently selected from a hole transport layer or an electron transport layer, and the material of the hole transport layer comprises an organic compound, wherein the organic compound comprises a dibenzothiophene sulfone compound with a structure as shown in Formula 1:

[0009]

[0010] Wherein, L is selected from unsubstituted or substituted aromatic amine groups, and the substituted groups include at least one of halogen atoms, alkoxy groups, hydrocarbon groups or aromatic groups.

[0011] This invention expands the planar conjugated structure of dibenzothiophene sulfone compounds by modulating their structure, giving them specific energy level structures, high mobility, and good chemical stability. This matches the energy level structure of perovskite materials, facilitating the effective separation of photogenerated charges and enabling them to perform well as hole transport materials. Furthermore, the functional groups in the compound structure can significantly passivate lead defects in perovskite films, ultimately forming a non-destructive interface to reduce non-radiative recombination losses, thereby improving the photoelectric conversion efficiency and stability of perovskite solar cells.

[0012] Preferably, the aromatic amine group includes a triphenylamine group or a carbazole group.

[0013] Preferably, L is selected from triphenylamine group as shown in Formula 2 or carbazole group as shown in Formula 3:

[0014]

[0015] Wherein, A1 is a carbon-carbon single bond, A2 is selected from an aromatic group, and R1 and R2 are each independently selected from at least one of -H, halogen atom, alkoxy group, hydrocarbon group or aromatic group.

[0016] More preferably, the L is selected from triphenylamine group as shown in Formula 2 or carbazole group as shown in Formula 3:

[0017]

[0018] Wherein, A1 is a carbon-carbon single bond, A2 is selected from phenyl, and R1 and R2 are each independently selected from at least one of -H, bromine atom, methoxy, tert-butyl or phenyl.

[0019] Preferably, the present invention provides an exemplary synthetic route for dibenzothiophene sulfone compounds with the structure shown in Formula 1, as follows:

[0020]

[0021] Specifically, under a nitrogen atmosphere, 2.51 mmol of bromotriphenylamine compound, 1.3 g (5.11 mmol) of pinacol diborate, and 0.74 g (7.54 mmol) were added to a 100 mL double-necked flask. 50 mL of 1,4-dioxane was added to the flask to ensure complete dissolution of the reactants. The flask was evacuated and filled with nitrogen, circulated three times. The catalyst Pd(dppf)Cl2·DCM ([1,1′-bis(diphenylphosphine)ferrocene]palladium(II)dichloromethane complex) (0.05 g, 0.06 mmol) was added to the flask. The vacuum and nitrogen circulation were repeated three more times. The reaction mixture was heated to 90 °C and reacted for 16 h. After cooling to room temperature, the reaction mixture was extracted with dichloromethane, washed three times with deionized water, and dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixed solvent of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent. The solid powder was then separated and recrystallized with n-hexane to obtain the intermediate product.

[0022] Under nitrogen atmosphere, the above intermediate (0.44 mmol), 2,8-dibromodibenzothiophene-5,5-dioxide (74.8 mg, 0.20 mmol), and potassium carbonate (277 mg, 2.00 mmol) were added to a 50 mL double-necked flask. 8 mL of ethylene glycol dimethyl ether and 2 mL of water (solvent) were added to the flask, and the mixture was pre-purged with nitrogen for 10 min to remove oxygen. The flask was then evacuated and purged three times with nitrogen. Under a nitrogen flow, TBAHS (tetrabutylammonium hydrogen sulfate) (0.01 g, 0.0029 mmol) and Pd(PPh3)4 (tetraphenylphosphine palladium) (0.01 g, 0.0087 mmol) were added to the flask. This process was repeated three times under vacuum and nitrogen circulation. The reaction mixture was heated to 90 °C and reacted for 6 h. After cooling, the mixture was extracted with dichloromethane, washed three times with deionized water, and then dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixture of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent to obtain the final product.

[0023] Furthermore, the present invention also provides another exemplary synthetic route for dibenzothiophene sulfone compounds with the structure shown in Formula 1, as follows:

[0024]

[0025] Specifically, under a nitrogen atmosphere, 2.51 mmol of a bromocarbazolyl compound, 1.3 g (5.11 mmol) of pinacol diborate, and 0.74 g (7.54 mmol) were added to a 100 mL double-necked flask. 50 mL of 1,4-dioxane was added to the flask to ensure complete dissolution of the reactants. The flask was evacuated and filled with nitrogen, circulated three times. The catalyst Pd(dppf)Cl2·DCM ([1,1′-bis(diphenylphosphine)ferrocene]palladium(II)dichloromethane complex) (0.05 g, 0.06 mmol) was added to the flask. The vacuum and nitrogen circulation were repeated three more times. The reaction mixture was heated to 90 °C and reacted for 16 h. After cooling to room temperature, the reaction mixture was extracted with dichloromethane, washed three times with deionized water, and dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixed solvent of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent. The solid powder was then separated and recrystallized with n-hexane to obtain the intermediate product.

[0026] Under nitrogen atmosphere, the above intermediate (0.44 mmol), 2,8-dibromodibenzothiophene-5,5-dioxide (74.8 mg, 0.20 mmol), and potassium carbonate (277 mg, 2.00 mmol) were added to a 50 mL double-necked flask. 8 mL of ethylene glycol dimethyl ether and 2 mL of water (solvent) were added to the flask, and the mixture was pre-purged with nitrogen for 10 min to remove oxygen. The flask was then evacuated and purged three times with nitrogen. Under a nitrogen flow, TBAHS (tetrabutylammonium hydrogen sulfate) (0.01 g, 0.0029 mmol) and Pd(PPh3)4 (tetraphenylphosphine palladium) (0.01 g, 0.0087 mmol) were added to the flask. This process was repeated three times under vacuum and nitrogen circulation. The reaction mixture was heated to 90 °C and reacted for 6 h. After cooling, the mixture was extracted with dichloromethane, washed three times with deionized water, and then dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixture of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent to obtain the final product.

[0027] Preferably, the first carrier transport layer is a hole transport layer, and the second carrier transport layer is an electron transport layer.

[0028] Preferably, the thickness of the hole transport layer is 2-10nm, for example, it can be 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, etc.

[0029] In this invention, by adjusting the thickness of the hole transport layer, hole carriers can be smoothly transported from the perovskite effect layer to the electrode layer. If the thickness is too small, holes cannot be effectively conducted within the hole transport layer, leading to a decrease in the efficiency of the perovskite solar cell; if the thickness is too large, hole carriers are not easily conducted out, thus affecting the efficiency of the perovskite solar cell.

[0030] Preferably, the thickness of the perovskite light-absorbing layer is 400-700 nm, for example, it can be 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, etc.

[0031] In this invention, the perovskite light-absorbing layer has the general formula ABX3, where A is CH3NH3. + CH(NH2)2 + Cs + or Rb + B is any combination of one or more of the following, where B is Pb. 2+ Sn 2+ Or Ge 2+ Any combination of one or more of them, X is Cl - ,Br - Or I - Any one or more of the following combinations.

[0032] In this invention, the material of the electron transport layer includes C. 60 Any one or a combination of several of the following: PCBM, TiO2, SnO2, ZnO, or ZnO-ZnS.

[0033] In this invention, the second electrode material is any one of Au, Ag, Al, or carbon electrode.

[0034] In a second aspect, the present invention provides a method for preparing a perovskite solar cell according to the first aspect, the method comprising the following steps:

[0035] A substrate is provided, a first electrode is formed on the substrate, a first carrier transport layer is formed on the first electrode, a perovskite light-absorbing layer is formed on the first carrier transport layer, a second carrier transport layer is formed on the perovskite light-absorbing layer, and a second electrode layer is formed on the second carrier transport layer.

[0036] The first carrier transport layer and the second carrier transport layer are each independently selected from either a hole transport layer or an electron transport layer, and the material of the hole transport layer includes organic compounds.

[0037] Preferably, the method for preparing the hole transport layer includes coating with a precursor solution containing an organic compound to prepare the hole transport layer.

[0038] Preferably, the precursor solution comprises an organic compound and a solvent, wherein the mass concentration of the organic compound is 1-5 mg / mL, for example, it can be 1 mg / mL, 1.2 mg / mL, 1.5 mg / mL, 1.8 mg / mL, 2 mg / mL, 2.2 mg / mL, 2.5 mg / mL, 2.8 mg / mL, 3 mg / mL, 3.2 mg / mL, 3.5 mg / mL, 3.8 mg / mL, 4 mg / mL, 4.2 mg / mL, 4.5 mg / mL, 4.8 mg / mL, 5 mg / mL, etc.

[0039] In this invention, by controlling the mass concentration of the organic hole transport layer material, the perovskite solar cell can have good photoelectric performance. If the mass concentration is too low, holes cannot be conducted well in the hole transport layer, resulting in a decrease in the efficiency of the perovskite solar cell. Conversely, if the mass concentration is too high, the concentration of the organic hole transport layer material will be too high, making it difficult for hole carriers to be conducted, thereby affecting the efficiency of the perovskite solar cell.

[0040] Preferably, the solvent includes at least one of ethylene glycol dimethyl ether, tetrahydrofuran, N,N-dimethylformamide, or dimethyl sulfoxide.

[0041] Preferably, the first carrier transport layer is a hole transport layer, and the second carrier transport layer is an electron transport layer.

[0042] Preferably, the method for preparing the first carrier transport layer includes coating the first electrode with a precursor solution containing the organic compound to prepare the first carrier transport layer.

[0043] Preferably, the present invention also provides a method for preparing the above-mentioned perovskite light-absorbing layer, which includes the following steps:

[0044] (1) Preparation of perovskite precursor solution;

[0045] (2) The perovskite precursor solution is coated onto the above substrate and heated to generate a perovskite light-absorbing layer.

[0046] In this invention, the solvent in the perovskite precursor solution includes, but is not limited to, any one or a combination of several of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), 1,3-dimethyl-2-imidazolinone (DMI), dimethylacetamide (DMAC), N,N-dimethylpropenylurea (DMPU), acetonitrile (ACN), or 2-mercaptoethanol (ME).

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] This invention provides an organic compound for perovskite solar cells. By modulating the structure of dibenzothiophene sulfone compounds, the planar conjugated structure of the molecules is expanded, giving them a specific energy level structure, high mobility, and good chemical stability. This matches the energy level structure of perovskite materials, which helps to effectively separate photogenerated charges, thus enabling them to have good hole transport capabilities as hole transport materials. Moreover, the functional groups contained in the compound structure can significantly passivate lead defects in perovskite films, ultimately forming a non-destructive interface to reduce non-radiative recombination losses, thereby improving the photoelectric conversion efficiency and stability of perovskite solar cells. Attached Figure Description

[0049] Figure 1 A comparison of the fluorescence spectra of the perovskite solar cells provided in Application Example 1 and Comparative Application Example 1 of this invention;

[0050] Figure 2 A comparison of the fluorescence lifetime spectra of the perovskite solar cells provided in Application Example 1 and Comparative Application Example 1 of this invention;

[0051] Figure 3 This is a comparison chart showing the stability of perovskite solar cells provided in Application Examples 1-5 and Comparative Application Example 1 of the present invention. Detailed Implementation

[0052] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be considered as specific limitations thereof.

[0053] Example 1

[0054] This embodiment provides a dibenzothiophene sulfone compound for perovskite solar cells, the structure of which is shown in Formula I:

[0055]

[0056] This embodiment provides the synthetic route for the dibenzothiophene sulfone compounds used in perovskite solar cells, as shown below:

[0057] Under a nitrogen atmosphere, 2.51 mmol of a bromocarbazolyl compound, 1.3 g (5.11 mmol) of pinacol diborate, and 0.74 g (7.54 mmol) were added to a 100 mL double-necked flask. 50 mL of 1,4-dioxane was added to the flask to ensure complete dissolution of the reactants. The flask was evacuated and filled with nitrogen, cyclically repeated three times. The catalyst Pd(dppf)Cl2·DCM ([1,1′-bis(diphenylphosphine)ferrocene]palladium(II)dichloromethane complex) (0.05 g, 0.06 mmol) was added to the flask. The evacuation and nitrogen cycling were repeated three more times. The reaction mixture was heated to 90 °C and reacted for 16 h. After cooling to room temperature, the reaction mixture was extracted with dichloromethane, washed three times with deionized water, and dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixed solvent of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent. The solid powder was then separated and recrystallized with n-hexane to obtain the intermediate product.

[0058] Under nitrogen atmosphere, the above intermediate (0.44 mmol), 2,8-dibromodibenzothiophene-5,5-dioxide (74.8 mg, 0.20 mmol), and potassium carbonate (277 mg, 2.00 mmol) were added to a 50 mL double-necked flask. 8 mL of ethylene glycol dimethyl ether and 2 mL of water (solvent) were added to the flask, and the mixture was pre-purged with nitrogen for 10 min to remove oxygen. The flask was then evacuated and purged three times with nitrogen. Under a nitrogen flow, TBAHS (tetrabutylammonium hydrogen sulfate) (0.01 g, 0.0029 mmol) and Pd(PPh3)4 (tetraphenylphosphine palladium) (0.01 g, 0.0087 mmol) were added to the flask. This process was repeated three times under vacuum and nitrogen circulation. The reaction mixture was heated to 90 °C and reacted for 6 h. After cooling, the mixture was extracted with dichloromethane, washed three times with deionized water, and then dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixture of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent to obtain the final product.

[0059] This embodiment also provides a precursor solution for an organic hole transport layer, an organic hole transport layer prepared therefrom, and a method for preparing the same, which includes the following steps:

[0060] An organic hole transport layer was deposited on the surface of a conductive glass substrate by spin coating. Specifically, the process included preparing a mixed solution of ethylene glycol dimethyl ether containing a compound of formula I with a mass concentration of 3 mg / mL, spin coating the mixed solution onto the surface of the conductive glass substrate at a speed of 3000 rpm for 30 s, followed by annealing at a temperature of 100 °C for 10 min to obtain an organic hole transport layer with a thickness of 6 nm.

[0061] Example 2

[0062] The difference between this embodiment and Example 1 is that the compound shown in Formula I is replaced with an equal amount of the compound shown in Formula II:

[0063]

[0064] This embodiment also provides a synthetic route for the compound shown in Formula II: Under a nitrogen atmosphere, a tert-butyl-substituted triphenylamino compound (2.51 mmol), pinacol diborate (1.3 g, 5.11 mmol), and potassium acetate (0.74 g, 7.54 mmol) were added to a 100 mL double-necked flask. 50 mL of 1,4-dioxane was added to the flask to ensure complete dissolution of the reactants. The flask was evacuated and filled with nitrogen, circulated three times. The catalyst Pd(dppf)Cl2·DCM ([1,1′-bis(diphenylphosphine)ferrocene]palladium(II)dichloromethane complex) (0.05 g, 0.06 mmol) was added to the flask. The vacuum and nitrogen circulation were repeated three more times. The reaction mixture was heated to 90 °C and reacted for 16 h. After cooling to room temperature, the reaction mixture was extracted with dichloromethane, washed three times with deionized water, and dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixed solvent of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent. The solid powder was then separated and recrystallized with n-hexane to obtain the intermediate product.

[0065] Under nitrogen atmosphere, the above intermediate (0.44 mmol), 2,8-dibromodibenzothiophene-5,5-dioxide (74.8 mg, 0.20 mmol), and potassium carbonate (277 mg, 2.00 mmol) were added to a 50 mL double-necked flask. 8 mL of ethylene glycol dimethyl ether and 2 mL of water (solvent) were added to the flask, and the mixture was pre-purged with nitrogen for 10 min to remove oxygen. The flask was then evacuated and purged three times with nitrogen. Under a nitrogen flow, TBAHS (tetrabutylammonium hydrogen sulfate) (0.01 g, 0.0029 mmol) and Pd(PPh3)4 (tetraphenylphosphine palladium) (0.01 g, 0.0087 mmol) were added to the flask. This process was repeated three times under vacuum and nitrogen circulation. The reaction mixture was heated to 90 °C and reacted for 6 h. After cooling, the mixture was extracted with dichloromethane, washed three times with deionized water, and then dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixture of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent to obtain the final product. All other steps were the same as in Example 1.

[0066] Example 3

[0067] The difference between this embodiment and Example 1 is that the compound shown in Formula I is replaced with an equal amount of the compound shown in Formula III:

[0068]

[0069] This embodiment also provides a synthetic route for the compound shown in Formula III: Under a nitrogen atmosphere, unsubstituted carbazole compound (2.51 mmol), pinacol diborate (1.3 g, 5.11 mmol), and potassium acetate (0.74 g, 7.54 mmol) were added to a 100 mL double-necked flask. 50 mL of 1,4-dioxane was added to the flask to ensure complete dissolution of the reactants. The flask was evacuated and filled with nitrogen, cyclically three times. The catalyst Pd(dppf)Cl2·DCM ([1,1′-bis(diphenylphosphine)ferrocene]palladium(II)dichloromethane complex) (0.05 g, 0.06 mmol) was added to the flask. The vacuum and nitrogen cycling were repeated three more times. The reaction mixture was heated to 90 °C and reacted for 16 h. After cooling to room temperature, the reaction mixture was extracted with dichloromethane, washed three times with deionized water, and dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixed solvent of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent. The solid powder was then separated and recrystallized with n-hexane to obtain the intermediate product.

[0070] Under nitrogen atmosphere, the above intermediate (0.44 mmol), 2,8-dibromodibenzothiophene-5,5-dioxide (74.8 mg, 0.20 mmol), and potassium carbonate (277 mg, 2.00 mmol) were added to a 50 mL double-necked flask. 8 mL of ethylene glycol dimethyl ether and 2 mL of water (solvent) were added to the flask, and the mixture was pre-purged with nitrogen for 10 min to remove oxygen. The flask was then evacuated and purged three times with nitrogen. Under a nitrogen flow, TBAHS (tetrabutylammonium hydrogen sulfate) (0.01 g, 0.0029 mmol) and Pd(PPh3)4 (tetraphenylphosphine palladium) (0.01 g, 0.0087 mmol) were added to the flask. This process was repeated three times under vacuum and nitrogen circulation. The reaction mixture was heated to 90 °C and reacted for 6 h. After cooling, the mixture was extracted with dichloromethane, washed three times with deionized water, and then dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixture of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent to obtain the final product. All other steps were the same as in Example 1.

[0071] Example 4

[0072] The difference between this embodiment and Example 1 is that the compound shown in Formula I is replaced with an equal amount of the compound shown in Formula IV:

[0073]

[0074] This embodiment also provides a synthetic route for the compound shown in Formula IV: Under a nitrogen atmosphere, unsubstituted triphenylamine compound (2.51 mmol), pinacol diborate (1.3 g, 5.11 mmol), and potassium acetate (0.74 g, 7.54 mmol) were added to a 100 mL double-necked flask. 50 mL of 1,4-dioxane was added to the flask to ensure complete dissolution of the reactants. The flask was evacuated and filled with nitrogen, circulated three times. The catalyst Pd(dppf)Cl2·DCM ([1,1′-bis(diphenylphosphine)ferrocene]palladium(II)dichloromethane complex) (0.05 g, 0.06 mmol) was added to the flask. The vacuum and nitrogen circulation were repeated three more times. The reaction mixture was heated to 90 °C and reacted for 16 h. After cooling to room temperature, the reaction mixture was extracted with dichloromethane, washed three times with deionized water, and dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixed solvent of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent. The solid powder was then separated and recrystallized with n-hexane to obtain the intermediate product.

[0075] Under nitrogen atmosphere, the above intermediate (0.44 mmol), 2,8-dibromodibenzothiophene-5,5-dioxide (74.8 mg, 0.20 mmol), and potassium carbonate (277 mg, 2.00 mmol) were added to a 50 mL double-necked flask. 8 mL of ethylene glycol dimethyl ether and 2 mL of water (solvent) were added to the flask, and the mixture was pre-purged with nitrogen for 10 min to remove oxygen. The flask was then evacuated and purged three times with nitrogen. Under a nitrogen flow, TBAHS (tetrabutylammonium hydrogen sulfate) (0.01 g, 0.0029 mmol) and Pd(PPh3)4 (tetraphenylphosphine palladium) (0.01 g, 0.0087 mmol) were added to the flask. This process was repeated three times under vacuum and nitrogen circulation. The reaction mixture was heated to 90 °C and reacted for 6 h. After cooling, the mixture was extracted with dichloromethane, washed three times with deionized water, and then dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixture of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent to obtain the final product. All other steps were the same as in Example 1.

[0076] Example 5

[0077] The difference between this embodiment and Example 1 is that the compound shown in Formula I is replaced with an equal amount of the compound shown in Formula V:

[0078]

[0079] This embodiment also provides a synthetic route for the compound shown in Formula V: Under a nitrogen atmosphere, a methoxylated triphenylamine compound (2.51 mmol), pinacol diborate (1.3 g, 5.11 mmol), and potassium acetate (0.74 g, 7.54 mmol) were added to a 100 mL double-necked flask. 50 mL of 1,4-dioxane was added to the flask to ensure complete dissolution of the reactants. The flask was evacuated and filled with nitrogen, circulated three times. The catalyst Pd(dppf)Cl2·DCM ([1,1′-bis(diphenylphosphine)ferrocene]palladium(II)dichloromethane complex) (0.05 g, 0.06 mmol) was added to the flask. The vacuum and nitrogen circulation were repeated three more times. The reaction mixture was heated to 90 °C and reacted for 16 h. After cooling to room temperature, the reaction mixture was extracted with dichloromethane, washed three times with deionized water, and dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixed solvent of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent. The solid powder was then separated and recrystallized with n-hexane to obtain the intermediate product.

[0080] Under nitrogen atmosphere, the above intermediate (0.44 mmol), 2,8-dibromodibenzothiophene-5,5-dioxide (74.8 mg, 0.20 mmol), and potassium carbonate (277 mg, 2.00 mmol) were added to a 50 mL double-necked flask. 8 mL of ethylene glycol dimethyl ether and 2 mL of water (solvent) were added to the flask, and the mixture was pre-purged with nitrogen for 10 min to remove oxygen. The flask was then evacuated and purged three times with nitrogen. Under a nitrogen flow, TBAHS (tetrabutylammonium hydrogen sulfate) (0.01 g, 0.0029 mmol) and Pd(PPh3)4 (tetraphenylphosphine palladium) (0.01 g, 0.0087 mmol) were added to the flask. This process was repeated three times under vacuum and nitrogen circulation. The reaction mixture was heated to 90 °C and reacted for 6 h. After cooling, the mixture was extracted with dichloromethane, washed three times with deionized water, and then dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixture of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent to obtain the final product. All other steps were the same as in Example 1.

[0081] Example 6

[0082] The difference between this embodiment and Example 1 is that the mass concentration of the compound with the structure shown in Formula I in the mixed solution is adjusted to 1 mg / mL to form an organic hole transport layer with a thickness of 2 nm. Everything else is the same as in Example 1.

[0083] Example 7

[0084] The difference between this embodiment and Example 1 is that the mass concentration of the compound with the structure shown in Formula I in the mixed solution is adjusted to 5 mg / mL to form an organic hole transport layer with a thickness of 10 nm. Everything else is the same as in Example 1.

[0085] Example 8

[0086] The difference between this embodiment and Example 1 is that the mass concentration of the compound with the structure shown in Formula I in the mixed solution is adjusted to 0.5 mg / mL to form an organic hole transport layer with a thickness of 1 nm. Everything else is the same as in Example 1.

[0087] Example 9

[0088] The difference between this embodiment and Example 1 is that the mass concentration of the compound with the structure shown in Formula I in the mixed solution is adjusted to 7 mg / mL to form an organic hole transport layer with a thickness of 15 nm. Everything else is the same as in Example 1.

[0089] Comparative Example 1

[0090] The difference between this comparative example and Example 1 is that the compound shown in Formula I is replaced with an equal amount of [2-(9H-carbazole-9-yl)ethyl]phosphonic acid, and the solvent is anhydrous ethanol. All other aspects are the same as in Example 1.

[0091] Comparative Example 2

[0092] The difference between this comparative example and Example 1 is that L is methyl, while everything else is the same as in Example 1.

[0093] Comparative Example 3

[0094] The difference between this comparative example and Example 1 is that the compound shown in Formula I is replaced with an equal amount of the compound shown in Formula A:

[0095]

[0096] The preparation method of the compound shown in Formula A includes the following steps, all of which are the same as in Example 1.

[0097] 2,8-Dibromodibenzothiophene-5,5-dioxide (3.47 g, 10 mmol), phenylboronic acid (1.22 g, 10 mmol), Pd(P(Ph)3)4(tetraphenylphosphine palladium) (0.57 g, 0.5 mmol), and K2CO3 (6.90 g, 50 mmol) were dissolved in 120 mL of toluene and 30 mL of ethanol in a 250 mL three-necked flask. The mixture was stirred continuously at 90 °C under a nitrogen atmosphere for 8 h. After cooling to room temperature, 200 mL of deionized water was added. The reaction mixture was extracted with dichloromethane (3 × 100 mL), dried over anhydrous magnesium sulfate, and the solvent was removed under vacuum to obtain a powder. The crude product was purified by silica gel column chromatography (petroleum ether / dichloromethane = 10:1, v / v) to obtain the final product.

[0098] Comparative Example 4

[0099] The difference between this comparative example and Example 1 is that the compound shown in Formula I is replaced with an equal amount of the compound shown in Formula B:

[0100]

[0101] The preparation method of the compound shown in Formula B includes the following steps, all of which are the same as in Example 1.

[0102] Under a nitrogen atmosphere, 2.51 mmol of a bromocarbazolyl compound, 1.3 g (5.11 mmol) of pinacol diborate, and 0.74 g (7.54 mmol) were added to a 100 mL double-necked flask. 50 mL of 1,4-dioxane was added to the flask to ensure complete dissolution of the reactants. The flask was evacuated and filled with nitrogen, cyclically repeated three times. The catalyst Pd(dppf)Cl2·DCM ([1,1′-bis(diphenylphosphine)ferrocene]palladium(II)dichloromethane complex) (0.05 g, 0.06 mmol) was added to the flask. The evacuation and nitrogen cycling were repeated three more times. The reaction mixture was heated to 90 °C and reacted for 16 h. After cooling to room temperature, the reaction mixture was extracted with dichloromethane, washed three times with deionized water, and dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixed solvent of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent. The solid powder was then separated and recrystallized with n-hexane to obtain the intermediate product.

[0103] Under nitrogen atmosphere, the above intermediate (0.44 mmol), 2,8-dibromodibenzothiophene (68.4 mg, 0.20 mmol), and potassium carbonate (277 mg, 2.00 mmol) were added to a 50 mL double-necked flask. 8 mL of ethylene glycol dimethyl ether and 2 mL of water (solvent) were added to the flask, and the mixture was pre-purged with nitrogen for 10 min to remove oxygen. The flask was then evacuated and purged three times with nitrogen. Under a nitrogen flow, TBAHS (tetrabutylammonium hydrogen sulfate) (0.01 g, 0.0029 mmol) and Pd(PPh3)4 (tetraphenylphosphine palladium) (0.01 g, 0.0087 mmol) were added to the flask. This process was repeated three times under vacuum and nitrogen circulation. The reaction mixture was heated to 90 °C and reacted for 6 h. After cooling, the mixture was extracted with dichloromethane, washed three times with deionized water, and then dried overnight with anhydrous sodium sulfate. The crude product was purified by column chromatography using a mixture of dichloromethane and petroleum ether (volume ratio 1:3) as the eluent to obtain the final product.

[0104] Application Examples 1-9 and Comparative Application Examples 1-4

[0105] Perovskite solar cells were prepared using the hole transport layers provided in Examples 1 to 9 and Comparative Examples 1 to 4, and the preparation methods are as follows:

[0106] (1) Cleaning the transparent conductive glass includes ultrasonic cleaning with detergent, deionized water, acetone and anhydrous ethanol respectively, and then drying it with a nitrogen gun; wherein the ultrasonic cleaning power is 100Hz and the ultrasonic cleaning time is 15min.

[0107] (2) An organic hole transport layer as described above is used.

[0108] (3) Preparation of a perovskite light-absorbing layer, specifically including:

[0109] MAI, FAI, MACl, and PbI2 were dissolved in a mixed solvent composed of dimethyl sulfoxide (DMSO) and dimethylformamide (DMF). The solution was heated at 70°C and stirred continuously for 1 hour to ensure complete dissolution, thus obtaining a perovskite precursor solution. The concentration ratio of FAI, MAI, and MACl was 0.95:0.05:0.14, the concentration of both FAI and PbI2 was 1.5 mol / L, and the volume ratio of DMSO to DMF in the mixed solvent was 1:9.

[0110] Perovskite films were prepared by spin coating at 5000 rpm for 50 seconds, followed by annealing at 120°C for 15 minutes to crystallize and form a FA film with a thickness of 500 nm. 0.95 MA 0.05 PbI3 perovskite light-absorbing layer.

[0111] (4) An electron transport layer C was deposited on the surface of the perovskite light-absorbing layer by vacuum evaporation. 60 Evaporation at a vacuum degree of 5×10 -4 The evaporation was carried out under Pa conditions at a rate of 0.15 A / s and a thickness of 20 nm.

[0112] (5) Another electron transport layer BCP is deposited on the surface of the electron transport layer by vacuum evaporation at a vacuum degree of 5×10⁻⁶. -4 The evaporation was carried out under Pa conditions at a rate of 0.2 A / s and a thickness of 8 nm.

[0113] (6) A metal electrode is prepared on the upper surface of the electron transport layer by physical vapor deposition. In a metal evaporation chamber, a 90 nm thick silver electrode is formed on the surface of the electron transport layer opposite to the perovskite light-absorbing layer using a thermal evaporation process, serving as the metal cathode; wherein the vacuum degree of the evaporation chamber is 5 × 10⁻⁶. -4 Pa, evaporation rate is 2A / s.

[0114] Test conditions

[0115] The perovskite solar cells provided in Application Examples 1 to 9 and Comparative Application Examples 1 to 4 were tested using the following methods:

[0116] (1) Photovoltaic performance: The JV performance of solar cell devices is mainly measured by the following four parameters: power conversion efficiency (PCE), short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF).

[0117] This invention uses a solar energy simulation testing system for measurement. The light source is a 500W xenon lamp solar spectrum simulator, calibrated with a standard silicon cell KG-5, under a solar intensity (AM 1.5G: 100mW / cm²). 2 Measurements are performed under the following conditions: A continuously varying voltage (-0.5V-1.3V) is applied across the battery terminals, and the battery's output current is measured (using a Keithley 2400 power supply). The product of these two measurements yields the JV test curve, which displays the photoelectric conversion efficiency of the device under different conditions.

[0118] (2) Fluorescence Spectroscopy: In this invention, a xenon lamp (Xe 900) with a wavelength of 500 nm was used to test the steady-state fluorescence spectrum of the perovskite layer. The fluorescence lifetime was measured using a picosecond pulsed laser (EPL 405).

[0119] The test results are shown in Table 1:

[0120] Table 1

[0121]

[0122] As shown in Table 1, the perovskite solar cells fabricated based on the hole transport layer materials with the specific structures provided in Examples 1-7 of this invention exhibit significantly improved open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency compared to the traditional 2PACz material. This is because the molecule possesses a high hole transport capability, thus enhancing the photoelectric conversion efficiency of the perovskite solar cell.

[0123] Comparing Application Example 1 and Application Examples 8-9, it can be seen that when the mass concentration of the compound shown in Formula I is too low (Application Example 8), holes cannot be well conducted in the hole transport layer, resulting in a decrease in the efficiency of the perovskite solar cell; when the mass concentration of the compound shown in Formula I is too high (Application Example 9), it will result in an excessively thick organic hole transport layer, which will hinder the conduction of hole carriers and affect the efficiency of the perovskite solar cell.

[0124] As can be seen from Comparative Application Examples 2 and 3, when the L group is not a triphenylamine group or a carbazole group, the molecule has almost no hole transport capability, so the final efficiency of the perovskite solar cell is lower than that of the cell based on 2PACz.

[0125] As can be seen from Comparative Application Example 4, the efficiency of the perovskite solar cell based on the hole transport material 2,8-dibromodibenzothiophene is still lower than that of Application Example 1. This is mainly because, compared to the thiophene-S-structure, the sulfonyl O=S=O structure and Pb 2+ With stronger coordination ability and better passivation effect, perovskite solar cells have higher efficiency.

[0126] from Figure 1 As can be seen, compared to Application Example 1, which uses a conventional organic hole transport material, resulting in a perovskite solar cell exhibiting higher photoluminescence intensity, Application Example 1, due to the use of an organic hole transport layer with a structure as shown in Formula I, exhibits lower photoluminescence intensity in the perovskite light-absorbing layer / NiO. x The fluorescence quenching at the interface was significantly enhanced, mainly due to the transfer of hole charge from the perovskite absorber layer to the hole transport layer, thereby reducing radiative relaxation from the excited state to the ground state. Simultaneously, the fluorescence lifetime spectrum ( Figure 2 As can also be seen in Example 1, treatment with a compound with the structure shown in Formula I significantly reduced the fluorescence lifetime of the perovskite film, further demonstrating that the introduction of dibenzothiophene sulfone compounds with specific structures effectively promoted hole separation at the hole transport layer / perovskite light-absorbing layer interface.

[0127] from Figure 3 It can be seen that the perovskite solar cells prepared from the dibenzothiophene sulfone compound organic hole transport materials provided by the present invention have significantly improved long-term operational stability.

[0128] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A perovskite solar cell, characterized in that, The perovskite solar cell comprises a substrate, a first electrode, a first carrier transport layer, a perovskite light-absorbing layer, a second carrier transport layer, and a second electrode, which are sequentially stacked. The first carrier transport layer and the second carrier transport layer are each independently selected from a hole transport layer or an electron transport layer. The material of the hole transport layer includes an organic compound, and the organic compound includes a dibenzothiophene sulfone compound with the structure shown in Formula 1. Wherein, L is selected from unsubstituted or substituted aromatic amine groups, and the substituted groups include at least one of halogen atoms, alkoxy groups, hydrocarbon groups or aromatic groups.

2. The perovskite solar cell according to claim 1, characterized in that, The aromatic amine group includes triphenylamine or carbazole; Preferably, L is selected from triphenylamine group as shown in Formula 2 or carbazole group as shown in Formula 3: Wherein, A1 is a carbon-carbon single bond, A2 is selected from an aromatic group, and R1 and R2 are each independently selected from at least one of -H, halogen atom, alkoxy group, hydrocarbon group or aromatic group.

3. The perovskite solar cell according to claim 2, characterized in that, The L is selected from triphenylamino group as shown in Formula 2 or carbazole group as shown in Formula 3: Wherein, A1 is a carbon-carbon single bond, A2 is selected from phenyl, and R1 and R2 are each independently selected from at least one of -H, bromine atom, methoxy, tert-butyl or phenyl.

4. The perovskite solar cell according to claim 2 or 3, characterized in that, The synthetic route for the dibenzothiophene sulfone compounds with the structure shown in Formula 1 includes the following steps: or, 5. The perovskite solar cell according to any one of claims 1-4, characterized in that, The first carrier transport layer is a hole transport layer, and the second carrier transport layer is an electron transport layer.

6. The perovskite solar cell according to any one of claims 1-5, characterized in that, The thickness of the hole transport layer is 2-10 nm; Preferably, the thickness of the perovskite light-absorbing layer is 400-700 nm.

7. A method for preparing a perovskite solar cell according to any one of claims 1-6, the method comprising the following steps: A substrate is provided, a first electrode is formed on the substrate, a first carrier transport layer is formed on the first electrode, a perovskite light-absorbing layer is formed on the first carrier transport layer, a second carrier transport layer is formed on the perovskite light-absorbing layer, and a second electrode layer is formed on the second carrier transport layer. The first carrier transport layer and the second carrier transport layer are each independently selected from either a hole transport layer or an electron transport layer, and the material of the hole transport layer includes organic compounds.

8. The method according to claim 7, wherein the method for preparing the hole transport layer comprises coating with a precursor solution containing an organic compound to prepare the hole transport layer; Preferably, the precursor solution comprises an organic compound and a solvent, wherein the mass concentration of the organic compound is 1-5 mg / mL.

9. The method according to claim 8, characterized in that, The solvent includes at least one of ethylene glycol dimethyl ether, tetrahydrofuran, N,N-dimethylformamide, or dimethyl sulfoxide.

10. The method according to claim 7, characterized in that, The first carrier transport layer is a hole transport layer, and the second carrier transport layer is an electron transport layer; Preferably, the method for preparing the first carrier transport layer includes coating the first electrode with a precursor solution containing the organic compound to prepare the first carrier transport layer.

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