Pyrrolyl-based carbazole bisphosphonate polymer, synthesis method therefor and use thereof

Abstract

The present invention aims to provide a pyrrolyl-based carbazole bisphosphonate polymer, a synthesis method therefor, and the use thereof. In the polymer, a conjugated structure is formed by linking two carbazole molecules via a pyrrole ring, and therefore the carrier transport efficiency when the material is applied to hole transport layers is ensured, the dipole moment of the molecule and the properties of an interface are well regulated, and the wettability and coverage effect with substrates are improved. Battery structures prepared by using the material have higher photoelectric conversion efficiency and stability.

Description

Pyrrole group-based bisphosphonic acid carbazole polymer, synthesis method and application thereof

[0001] The present application claims priority to the Chinese patent application No. 2024113281581, filed on September 24, 2024 in the China Patent Office and entitled “Pyrrole group-based bisphosphonic acid carbazole polymer, synthesis method and application thereof”, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application mainly relates to the technical field of solar cells, in particular to a pyrrole group-based bisphosphonic acid carbazole polymer, a synthesis method and application of the polymer in perovskite solar cells. BACKGROUND

[0003] The statements herein are provided only to enhance understanding of the present application and are not necessarily intended to constitute the prior art.

[0004] Perovskite solar cells have attracted extensive attention in the photovoltaic field due to their excellent photoelectric properties and simple preparation process. Compared with traditional crystalline silicon cells, perovskite solar cells have the advantages of simple preparation process, high defect tolerance, adjustable band gap, etc. In recent years, they have developed rapidly, and their photoelectric conversion efficiency has once exceeded 25%. Existing researches have shown that among various structures of perovskite solar cells, the transverse structure (p-i-n) has the advantages of small hysteresis, fast response speed, high stability, etc., and the preparation process is simple, which is more suitable for mass production. The transverse structure perovskite solar cell is generally stacked from bottom to top by a transparent conductive substrate, a hole transport layer, a perovskite light absorption layer, an electron transport layer and a metal electrode. Among these structures, the hole transport layer plays an important role in the extraction and transmission of holes, perovskite crystallization, surface passivation and device stability, etc.

[0005] In existing researches on transverse perovskite solar cells, the hole transport layer material is mainly poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA). However, this material is expensive, and its strong hydrophobicity often leads to poor coverage of the perovskite film, which reduces the stability of the cell. Although the hole transport layer prepared by doping and modifying NiOx has certain improvement in material cost and device stability, the preparation process is relatively complex.

[0006] In view of the above problems, some new hole transport layer materials have also been developed, among which self-assembled monolayer materials (SAM) are representative. The advantages of SAM materials are (1) simple preparation and small amount of use; (2) various film forming methods, suitable for large-scale manufacturing; (3) can be chemically bonded with the substrate material, improving the stability of the battery; (4) the thickness of the thin film is very small, which reduces the series resistance and further improves the battery efficiency. Therefore, the development and design of new SAM layer materials play an important role in promoting the development of trans-perovskite solar cells.

[0007] The existing SAM materials are mainly carbazole molecules containing phosphonic acid groups, such as Me-4PACz, MeO-2PACz, etc. The phosphonic acid groups in these molecules can combine with NiOx to form strong bonds, which improves the heat resistance and stability of the material to some extent; and the structure of the carbazole ring can provide a lower ionization potential and a larger dipole moment to optimize the energy level matching and hole transport efficiency of perovskite and NiOx. However, the bonding force with the substrate is still not stable enough, and the wettability of the interface of the formed hole transport layer is poor, resulting in poor coverage effect and performance of the perovskite thin film prepared thereon. SUMMARY

[0008] The present application aims to provide a pyrrole group-based bisphosphonic carbazole polymer and a synthesis method and application thereof. The conjugated structure formed by connecting double carbazole molecules through a pyrrole ring can ensure the carrier transport efficiency of the material when applied to the hole transport layer, and can well regulate the dipole moment of the molecule and the properties of the interface, improve the wettability with the substrate and the coverage effect, and the battery structure prepared by using the material has higher photoelectric conversion efficiency and stability.

[0009] To achieve the above purpose, the specific scheme provided by the present application is as follows.

[0010] A pyrrole group-based bisphosphonic carbazole polymer, the structure general formula of which is as follows:

[0011]

[0012] In the formula, R is hydrogen, methyl, methoxy, halogen, phenyl, halobenzyl, triphenylamine group, etc.; and the value of n is any integer between 2 and 6.

[0013] The present application also provides a synthesis method of the above polymer, comprising the following steps:

[0014] S1: reacting compound under the conditions of a catalyst and liquid bromine to generate compound ;

[0015] [Corrected according to Rule 91 09.06.2025] S2: compound In the presence of tetrakis(dimethylamino)ethylene (TADE) to generate compound

[0016] [Rule 91 correct 09.06.2025] S3: compound Cyclization with ammonium acetate in glacial acetic acid to generate compound

[0017] S4: compound Reaction with dibromoalkane under basic conditions to generate compound

[0018] S5: compound Reaction with triethyl phosphite to generate compound

[0019] [Rule 91 correct 09.06.2025] S6: compound Dissolved in 1,4-dioxane, reacted with trimethylsilyl bromide under inert atmosphere; then add methanol to continue the reaction; finally add deionized water to react, filter and dry to obtain compound

[0020] Wherein R is hydrogen, methyl, methoxy, halogen, phenyl, halobenzyl, triphenylamine, etc; n is any integer between 2 and 6.

[0021] Further, the catalyst in step S1 is AlCl3, and AlCl3 and liquid bromine are added to compound , then add ether, react in ice water bath for 1h, then reduce to room temperature, and separate by column chromatography to obtain compound

[0022] [Rule 91 correct 09.06.2025] Further, tetrahydrofuran is also added in step S2 for dissolution, heated to 70℃ and stirred for 1h, and then purified by column chromatography to obtain compound

[0023] Further, the reaction temperature in step S3 is 120℃, and the reaction time is 1h, and then separated by column chromatography to obtain compound

[0024] Further, tetrabutylammonium bromide and 50wt% potassium hydroxide solution are also added in step S4; after stirring and heating to 70℃, react for 12h, and then separate by column chromatography to obtain compound

[0025] ​​​​​Further, the reaction temperature in the step S5 is 165 DEG C, the reaction time is 20h, and the compound is obtained by column chromatography separation 。

[0026] Further, the inert atmosphere in the step S6 is nitrogen, the reaction is carried out at room temperature for 24h under the nitrogen environment, the reaction is continued for 8h after adding methanol, the reaction is carried out for 12h after adding deionized water, and the compound is obtained by filtering after evaporating the solution 。

[0027] The synthesis reaction equation of the pyrrole group-based bisphosphonic acid carbazole polymer provided by the application is as follows:

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034] Wherein, R is hydrogen, methyl, methoxy, halogen, phenyl, halobenzyl, triphenylamine group, etc.; n is any integer between 2 and 6.

[0035] The application further provides a preparation method of a perovskite solar cell, which uses the pyrrole group-based bisphosphonic acid carbazole polymer material as a hole transport layer, and comprises the following steps:

[0036] A transparent conductive substrate is provided, and a NiO x layer is formed on the transparent conductive substrate; the pyrrole group-based bisphosphonic acid carbazole polymer material is dissolved in anhydrous methanol to obtain a self-assembled monolayer solution, which is coated on the NiO x layer and annealed to obtain a hole transport layer; a perovskite light-absorbing layer, an electron transport layer and a top electrode are sequentially prepared on the hole transport layer.

[0037] Further, the concentration of the self-assembled monolayer solution is 0.1-10mg / mL, the annealing temperature on the NiO x layer is 60-100 DEG C, and the annealing time is 2-10min.

[0038] Further, the transparent conductive substrate is ultrasonically cleaned with deionized water, acetone and isopropanol in sequence before preparation, and then dried with nitrogen and treated with a UV-ozone cleaning machine on the surface of the substrate.

[0039] Further, the transparent conductive substrate is selected from one of the following materials: fluorine-doped tin oxide conductive glass (FTO) and indium-doped tin oxide conductive glass (ITO).

[0040] Further, the preparation of the perovskite light-absorbing layer comprises: weighing a certain amount of MAI (methylammonium iodide), FAI (formamidinium iodide), FABr (formamidinium bromide), PbI2 (lead iodide) and PbBr2 (lead bromide) to prepare a MA 0.1 FA 0.9 Pb(I 0.85 Br 0.15 )3 perovskite precursor solution, and the perovskite light-absorbing layer is obtained after spin-coating and annealing on the hole transport layer, the annealing temperature is 60-150 DEG C, and the annealing time is 2-30 min.

[0041] Further, the electron transport layer is prepared by an evaporation method, and C 60 70 or PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) is evaporated on the surface of the perovskite light-absorbing layer to obtain an electron transport layer with a thickness of 1-10 nm.

[0042] Further, the top electrode is prepared by a vacuum evaporation method under the condition that the vacuum degree is 5*10 -4 Pa, and is selected from one of the following materials: gold, silver and copper, and has a thickness of 500 nm.

[0043] Compared with the prior art, the present application has obvious advantages, specifically, the pyrrole group-based bisphosphonic acid carbazole polymer and synthesis method provided by the above technical solution can form a conjugated structure by connecting a double carbazole molecule through a pyrrole ring, which can better regulate the dipole moment and interface properties of the molecule while ensuring the hole transport capability of the material; and the bisphosphonic acid group structure also makes it more stable to combine with the substrate, thereby improving the wettability and coverage effect of the perovskite solution. The substituents on the carbazole group or the carbon chain length between the carbazole group and the phosphonic acid group can be freely changed as needed, so as to adjust the solubility, stacking mode, energy level and other properties of the molecule, thereby improving the photoelectric performance of the material. The processes and conditions involved in the molecular synthesis route are relatively simple, and the product can be mass-produced in a conventional environment, thereby meeting the needs of industrialization.

[0044] The biphosphonic acid carbazole polymer is used as a self-assembled monolayer, and is applied to a hole transport layer of a perovskite solar cell, so that the problem of the perovskite layer not being easy to cover and the complex preparation process of the hole transport layer material in the prior art is solved. The conjugated structure formed by the pyrrole ring and the bica rbazole molecule in the molecule guarantees excellent hole transport capacity and photovoltaic performance of the material, the terminal biphosphonic acid group strengthens the connection between the material and the substrate, and the stability of the material is improved, and the process and conditions for synthesizing the molecules are relatively simple, and are suitable for large-scale industrialization. BRIEF DESCRIPTION OF DRAWINGS

[0045] Fig. 1 is a synthesis path diagram of the biphosphonic acid carbazole polymer in the embodiment of the present application.

[0046] Fig. 2 is a schematic diagram of a battery structure using the biphosphonic acid carbazole polymer in the embodiment of the present application.

[0047] In the figure, the labels are respectively: 10, a transparent conductive substrate; 20, a hole transport layer; 30, a perovskite light absorption layer; 40, an electron transport layer; and 50, a top electrode. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments.

[0049] In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more; the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0050] The present embodiment provides a biphosphonic acid carbazole polymer based on a pyrrole group, and the structural general formula is as follows:

[0051]

[0052] In the formula, R is hydrogen, methyl, methoxy, halogen, phenyl, halobenzyl, triphenylamine group, etc.; and the value of n is any integer between 2 and 6.

[0053] The polymer molecules provided by the embodiment are mainly applied to perovskite battery structures. In the structure of a transverse perovskite battery, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) is mainly used as a hole transport layer material in the prior art. However, due to the strong hydrophobicity of the material itself, the wettability and covering effect of the perovskite thin film are poor, and the device performance and stability are reduced.

[0054] The conjugated structure formed by the pyrrole ring and the double carbazole molecule in the polymer molecules of the embodiment ensures excellent hole transport capacity and photovoltaic performance of the material. The double phosphonic acid group at the end strengthens the connection between the material and the substrate, and improves the stability of the material.

[0055] The principles and technical effects of the present application are further described below through specific examples and comparative examples. The chemical name of the compound I-1 provided in Example 1 is 1-(9H-carbazol-3-yl)ethanone, and the compounds II-1 to VII-1 are intermediate products or final products.

[0056] Embodiment

[0057] Referring to FIG. 1, the present embodiment provides a synthesis method of a pyrrole group-based bisphosphonic carbazole polymer, including the following steps:

[0058] Step 1: 2.302 g of compound I-1 (11 mmol), 0.5 g of aluminum trichloride, and 0.6 ml of liquid bromine (11 mmol) were added to a 150 ml round-bottom flask, then 20 ml of ether was added, and the reaction was carried out in an ice water bath for 1 hour and then restored to room temperature. White solid 2.85 g, i.e., compound II-1, was obtained by column chromatography separation, and the yield was 90%.

[0059] Step 2: 2.75 g of compound II-1 (9.54 mmol), 0.33 g of tetra(dimethylamino)ethylene (5.72 mmol), and 50 ml of tetrahydrofuran were added to a 150 ml round-bottom flask. The solution was heated to 70°C and stirred for 1 hour. White solid 3.18 g, i.e., compound III-1, was obtained by column chromatography purification, and the yield was 80%.

[0060] Step 3: 3.03 g of compound III-1 (7.28 mmol) and 1.157 g of ammonium acetate (15 mmol) were added to a 100 ml round-bottom flask, and then 45 ml of glacial acetic acid was added and stirred to dissolve. The solution was heated to 120°C and refluxed for 12 hours. White solid 1.1 g, i.e., compound IV-1, was obtained by column chromatography purification, and the yield was 38%.

[0061] Step 4: 0.99 g of compound IV-1 (2.5 mmol), 17 ml of 1,2-dibromoethane, 0.192 g of tetrabutylammonium bromide (0.6 mmol) and 14 ml of 50 wt% potassium hydroxide solution were sequentially added into a 100 ml round-bottom flask. After stirring and heating to 70°C, the reaction was carried out for 12 hours. Column chromatography was used for purification to obtain 0.917 g of white solid, i.e. compound V-1, with a yield of 60%.

[0062] Step 5: 0.8 g of compound V-1 (1.31 mmol), 8 ml of triethyl phosphite were added into a 50 ml round-bottom flask. After stirring and dissolving, the reaction was carried out by heating to reflux at 165°C for 20 hours. Column chromatography was used for purification to obtain 0.856 g of light yellow oil, i.e. compound VI-1, with a yield of 90%.

[0063] Step 6: 0.75 g of compound VI-1 (1.03 mmol) was added into a 250 ml round-bottom flask. After replacing nitrogen, 25 ml of 1,4-dioxane and 8 ml of trimethylsilyl bromide were added. The reaction was carried out by stirring at room temperature for 24 hours. Then, 40 ml of methanol was added for further reaction for 8 hours. Finally, 80 ml of deionized water was added for reaction for 12 hours. After the reaction was completed, the solution was evaporated and filtered to obtain the final product, i.e. compound VII-1.

[0064] The embodiment also provides a preparation method of a perovskite solar cell. The final product, i.e. compound VII-1, obtained by the above synthesis method is used as a hole transport layer material. The preparation method comprises the following steps:

[0065] Step 1: A transparent conductive substrate 10 was provided. The substrate was ultrasonically cleaned with deionized water, acetone and isopropanol in sequence, and then dried with nitrogen. Then, the surface of the substrate was treated by a UV-ozone cleaner.

[0066] Step 2: A NiO x layer was prepared by spin coating a NiO x solution with a concentration of 30 mg / ml on the surface of the transparent conductive substrate 10. x The compound VII-1 synthesized by the above method was weighed as a self-assembled monolayer material, and a self-assembled monolayer material solution with a concentration of 0.5 mg / ml was prepared by using anhydrous methanol. The solution was spin coated on the NiO 0.1 layer, and a hole transport layer 20 was obtained after annealing.

[0067] Step 3: A MAI, FAI, FABr, PbI2 and PbBr2 solution with a concentration of 1.0 M was prepared. The solution was spin coated on the surface of the hole transport layer 20, and a perovskite light-absorbing layer 30 was obtained after annealing. 0.9 0.85 0.15 Br​​

[0068] Step 4: A layer of 20 nm C 60 was evaporated on the surface of the perovskite light-absorbing layer 30 to obtain an electron transport layer 40.

[0069] Step 5: A 100 nm gold top electrode 50 was prepared by vacuum evaporation on the surface of the electron transport layer 40 under the condition of a vacuum degree of 5 x 10 -4 Pa, to complete the preparation of the perovskite solar cell.

[0070] Comparative Example 1

[0071] This comparative example used MeO-2PACz as a hole transport layer to prepare a trans- perovskite solar cell, including the following steps:

[0072] Step 1: A transparent conductive substrate 10 was provided, and the substrate was ultrasonically cleaned with deionized water, acetone, isopropanol, and then dried with nitrogen. After that, the surface of the substrate was treated with an ultraviolet ozone cleaning machine.

[0073] Step 2: A NiO x solution with a concentration of 30 mg / ml was spin-coated on the surface of the transparent conductive substrate 10 to prepare a NiO x layer. Then MeO-2PACz was weighed and dissolved in anhydrous methanol to prepare a SAM (Self-assembled Monolayer) solution with a concentration of 0.5 mg / ml. The SAM solution was spin-coated on the NiO x layer, and after annealing, a hole transport layer 20 was obtained.

[0074] Step 3: A certain amount of MAI, FAI, FABr, PbI2, and PbBr2 was weighed to prepare a MA 0.1 FA 0.9 Pb(I 0.85 Br 0.15 )3 perovskite precursor solution with a concentration of 1.0 M. After spin-coating and annealing, a perovskite light-absorbing layer 30 was obtained.

[0075] Step 4: A layer of 20 nm C 60 was evaporated on the surface of the perovskite light-absorbing layer to obtain an electron transport layer 40.

[0076] Step 5: A 100 nm gold top electrode 50 was prepared by vacuum evaporation on the surface of the electron transport layer under the condition of a vacuum degree of 5 x 10 -4 Pa, to complete the preparation of the perovskite solar cell.

[0077] A standard solar light intensity calibration was performed using a solar light simulator, and the area of the perovskite solar cell was 1.0 cm 2The perovskite battery devices obtained in the above examples and comparative examples were subjected to IV test for a long period of time, the starting voltage was set to 1.95 V, the cut-off voltage was set to 0 V, the range was set to 100 mA, and the J SC (Short-circuit current density), V OC (open-circuit voltage), FF (fill factor) and PCE (conversion efficiency), the results were kept to two decimal places, and the test results are shown in the following table.

[0078] Device J SC (mA·cm -2 )V OC (V)FF(%)PCE(%)Example 120.781.2384.3321.55Comparative Example 121.001.2281.5320.89

[0079] From the test data obtained from the experiment, it can be seen that the self-assembled monolayer material based on the pyrrole group bisphosphonic carbazole is used in the hole transport layer of the perovskite solar cell in Example 1, which improves the carrier transport capacity of the hole transport layer and the stability of the interface structure. Compared with the MeO-2PACz material used as the hole transport layer in Comparative Example 1, the fill factor and photoelectric conversion efficiency of the battery device are greatly improved. The process and conditions involved in the molecular synthesis route are relatively simple, and mass production can be achieved under conventional environment, meeting the needs of industrialization.

[0080] The above examples are only preferred embodiments of the present application, and it should be noted that for ordinary skilled in the art, without departing from the principles of the present application, a variety of changes, modifications, replacements and deformations can be made to these examples, and these technical solutions after equivalent replacement of the claims of the present application, all fall within the protection scope of the present application, the protection scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A pyrrole group-based bisphosphonate carbazole polymer, characterized by, The structural general formula is as follows: ； In the formula, R is hydrogen, methyl, methoxy, halogen, phenyl, halobenzyl, triphenylamine group, etc.; n is an integer between 2 and 6.

2. [Rule 91 correction 09.06.2025] A method for the synthesis of a bisphosphonate carbazole polymer based on pyrrole groups, characterized in that, The method comprises the steps of: S1 : The compound under catalytic and liquid bromine conditions to form the compound S2: compound In the presence of tetrakis(dimethylamino)ethylene (TADE) to form compounds S3: compound Cyclization with ammonium acetate in glacial acetic acid gives the compound S4: compound with a dibromoalkane under basic conditions to obtain a compound S5: compound Compound obtained after reaction with triethyl phosphite S6: Compound Dissolved in 1,4-dioxane and reacted with trimethylsilyl bromide under inert atmosphere; then methanol was added and reacted; finally deionized water was added and reacted, and compound 1 was obtained after filtration and drying In the formula, R is hydrogen, methyl, methoxy, halogen, phenyl, halobenzyl, triphenylamine group, etc.; n is an integer between 2 and 6.

3. The method of synthesis according to claim 2, wherein, The catalyst in the step S1 is AlCl3, and AlCl3 and liquid bromine are added into the compound , and then ether is added. The mixture is placed in an ice water bath and reacted for 1 h, and then is lowered to room temperature. The compound is obtained by column chromatography.

4. The method of synthesis of claim 2, wherein, The step S2 is also added with tetrahydrofuran for dissolution, warmed to 70°C and stirred for 1 h, and the compound is obtained by column chromatography purification. ​ 5. The method of synthesis of claim 2, wherein, The reaction temperature in the step S3 is 120°C, the reaction time is 1 h, and the compound is obtained by column chromatography separation. ​ 6. [Amended according to Rule 91 on 09.06.2025] The method of synthesis according to claim 2, characterized in that, The step S4 also added with tetrabutylammonium bromide and 50wt% potassium hydroxide solution; stirring to 70°C after heating reaction 12h, separated by column chromatography to obtain compound 7. The method of synthesis of claim 2, wherein, The reaction temperature in the step S5 is 165°C, the reaction time is 20 h, and the compound is obtained by column chromatography separation. ​ 8. [Amended according to Rule 91 on 09.06.2025] The method of synthesis according to claim 2, characterized in that, The inert atmosphere in the step S6 is nitrogen, and the reaction is carried out at room temperature for 24 h under the nitrogen atmosphere, and then the reaction is continued for 8 h after the addition of methanol, and then the reaction is continued for 12 h after the addition of deionized water, and then the compound is obtained by filtration after the evaporation of the solution 9. A method of manufacturing a perovskite solar cell, characterized by, Applying the pyrrole group-based bisphosphonic carbazole polymer according to any one of claims 1-8 as a hole transport layer, comprising the steps of: A transparent conductive substrate is provided, and a NiO x layer is formed on the transparent conductive substrate; a self-assembled monolayer solution is prepared by dissolving a pyrrole group-based bisphosphonic carbazole polymer material in anhydrous methanol, coated on the NiO x layer and annealed to obtain a hole transport layer; a perovskite light-absorbing layer, an electron transport layer and a top electrode are sequentially prepared on the hole transport layer.

10. The method of claim 9, wherein the perovskite solar cell is prepared by the steps of: The concentration of the self-assembled monolayer solution is 0.1-10 mg / mL, the annealing temperature on the NiO x layer is 60-100℃, and the annealing time is 2-10 min.

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