A pyrrole-based bisphosphonic acid carbazole polymer and its synthesis method and application

Abstract

The present invention aims to provide a pyrrole-based bisphosphonic acid carbazole polymer, a synthesis method, and applications. The polymer forms a conjugated structure by connecting biscarbazole molecules via pyrrole rings, which can ensure the carrier transport efficiency of the material when used in a hole transport layer, and effectively regulate the molecular dipole moment and interface properties, thereby improving the wettability and coverage effect with the substrate. The battery structure prepared using the material has higher photoelectric conversion efficiency and stability.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of solar cells, and in particular to a pyrrole-based bisphosphonic acid carbazole polymer, a synthesis method and application of the polymer in perovskite solar cells. Background Art

[0002] Perovskite solar cells (PNSs) have garnered widespread attention in the photovoltaic field due to their excellent optoelectronic properties and simple fabrication process. Compared to traditional crystalline silicon cells, PNSs offer advantages such as simplified fabrication, high defect tolerance, and tunable band gap. They have experienced rapid development in recent years, with their power conversion efficiency exceeding 25%. Previous studies have shown that among various PNS structures, those with an inverted (PIN) structure offer advantages such as low hysteresis, fast response, and high stability. Their simplified fabrication process also makes them more suitable for mass production. Inverted PNSs are typically constructed from a transparent conductive substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and metal electrodes stacked from bottom to top. In these structures, the hole transport layer plays a crucial role in hole extraction and transport, perovskite crystallization, surface passivation, and device stability.

[0003] In existing research on inverse perovskite solar cells, the main hole transport layer material is poly(4-phenyl)(2,4,6-trimethylphenyl)amine) (PTAA). However, this material is expensive, and its strong hydrophobicity often leads to poor perovskite film coverage, reducing cell stability. While doping and modifying NiOx to prepare a hole transport layer offers some improvements in material cost and device stability, the preparation process is relatively complex.

[0004] To address the above issues, a number of new hole transport layer materials have been developed, with self-assembled monolayer materials (SAMs) being a prime example. The advantages of SAM materials are (1) simple preparation and low usage; (2) diverse film-forming methods, making them suitable for large-scale manufacturing; (3) the ability to chemically bond with the substrate material, improving battery stability; and (4) the thin film thickness, which reduces series resistance and further improves battery efficiency. Therefore, the development and design of new SAM layer materials plays an important role in promoting the development of inverse perovskite solar cells.

[0005] Existing SAM materials are mostly based on carbazole molecules containing phosphonic acid groups, such as Me-4PACz and MeO-2PACz. The phosphonic acid groups in these molecules can form a strong bond with NiOx, which improves the material's heat resistance and stability to a certain extent. The carbazole ring structure can provide a low ionization potential and a large dipole moment to optimize the energy level matching and hole transport efficiency between the perovskite and NiOx. However, the bonding strength with the substrate is still not strong enough, and the resulting hole transport layer has poor wettability at the interface, resulting in poor coverage and performance of the perovskite film prepared on it. Summary of the Invention

[0006] The present invention aims to provide a pyrrole-based bisphosphonic acid carbazole polymer, a synthesis method, and applications. The polymer forms a conjugated structure by connecting biscarbazole molecules via pyrrole rings, which can ensure the carrier transport efficiency of the material when used in a hole transport layer, and effectively regulate the molecular dipole moment and interface properties, thereby improving the wettability and coverage effect with the substrate. The battery structure prepared using the material has higher photoelectric conversion efficiency and stability.

[0007] To achieve the above objectives, the present invention provides the following specific solutions.

[0008] A pyrrole-based bisphosphonic acid carbazole polymer, the general structural formula of which is as follows:

[0009]

[0010] Wherein: R is hydrogen, methyl, methoxy, halogen, phenyl, halogenated benzyl, triphenylamine, etc.; the value of n is any integer between 2 and 6.

[0011] The present invention also provides a method for synthesizing the above polymer, comprising the steps of:

[0012] S1: Compound Under the conditions of catalyst and liquid bromine, the compound is generated ;

[0013] S2: Compound Under the action of tetrakis(dimethylamino)ethylene (TADE), the compound is generated. ;

[0014] S3: Compound Reaction with ammonium acetate in glacial acetic acid to give compound ;

[0015] S4: Compound Reacting with dibromoalkane under alkaline conditions to obtain compound ;

[0016] S5: Compound After reacting with triethyl phosphite, the compound ;

[0017] S6: Compound Dissolve in 1,4-dioxane and react with trimethylsilyl bromide under inert atmosphere; then add methanol to continue the reaction; finally add deionized water to react, filter and dry to obtain the compound ;

[0018] Wherein R is hydrogen, methyl, methoxy, halogen, phenyl, halogenated benzyl, triphenylamine, etc.; the value of n is any integer between 2 and 6.

[0019] Furthermore, in step S1, the catalyst is AlCl3, and in the compound Add AlCl3 and liquid bromine, then add ether, place in an ice-water bath to react for 1 hour, then cool to room temperature, and separate by column chromatography to obtain compound .

[0020] Furthermore, tetrahydrofuran was added to dissolve the compound in step S2, and the mixture was heated to 70°C and stirred for 1 hour, and purified by column chromatography to obtain the compound .

[0021] Furthermore, in step S3, the reaction temperature is 120°C, the reaction time is 1 h, and the compound is separated by column chromatography. .

[0022] Furthermore, tetrabutylammonium bromide and 50 wt% potassium hydroxide solution were added in step S4; the mixture was stirred and heated to 70°C for 12 hours, and the compound was separated by column chromatography to obtain .

[0023] Furthermore, in step S5, the reaction temperature is 165°C, the reaction time is 20h, and the compound is separated by column chromatography. .

[0024] Furthermore, in step S6, the inert atmosphere is nitrogen, the reaction is carried out at room temperature under nitrogen for 24 hours, methanol is added and the reaction is continued for 8 hours, deionized water is added and the reaction is continued for 12 hours, the solution is evaporated and filtered to obtain the compound .

[0025] The synthesis reaction equation of the pyrrole-based bisphosphonic acid carbazole polymer provided by the present invention is as follows:

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032] Wherein, R is hydrogen, methyl, methoxy, halogen, phenyl, halogenated benzyl, triphenylamine, etc.; the value of n is any integer between 2 and 6.

[0033] The present invention also provides a method for preparing a perovskite solar cell, using the above-mentioned pyrrole-based bisphosphonic acid carbazole polymer material as a hole transport layer, comprising the steps of:

[0034] A transparent conductive substrate is provided, and NiO is formed on the transparent conductive substrate. x The bisphosphonic acid carbazole polymer material based on the pyrrole group is dissolved in anhydrous methanol to obtain a self-assembled monolayer solution, which is coated on the NiO x A perovskite light absorbing layer, an electron transport layer and a top electrode are sequentially prepared on the hole transport layer.

[0035] Furthermore, the concentration of the self-assembled monolayer solution is 0.1-10 mg / mL. x The annealing temperature on the layer is 60~100℃, and the annealing time is 2~10min.

[0036] Furthermore, before preparation, the transparent conductive substrate is ultrasonically cleaned with deionized water, acetone, and isopropyl alcohol in sequence, then blown dry with nitrogen, and then the surface of the substrate is treated with an ultraviolet ozone cleaner.

[0037] Furthermore, the transparent conductive substrate is composed of a material selected from fluorine-doped tin oxide conductive glass (FTO) and indium-doped tin oxide conductive glass (ITO).

[0038] Furthermore, the preparation of the perovskite light absorbing layer includes: weighing a certain amount of MAI (methylamine iodide), FAI (formamidine iodide), FABr (formamidine bromide), PbI2 (lead iodide) and PbBr2 (lead bromide) to prepare a MA solution with a concentration of 1.0M. 0.1 FA 0.9 Pb(I 0.85 Br 0.15 )3 perovskite precursor solution is spin-coated on the hole transport layer and annealed to obtain a perovskite light absorbing layer, the annealing temperature is 60~150℃, and the annealing time is 2~30min.

[0039] Furthermore, the electron transport layer is prepared by evaporation, and C is evaporated on the surface of the perovskite light absorbing layer. 60 or PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) to obtain an electron transport layer with a thickness of 1~10nm.

[0040] Furthermore, the top electrode is deposited by vacuum evaporation at a vacuum degree of 5×10 -4 Pa, and is composed of one material selected from gold, silver, and copper, with a thickness of 500nm.

[0041] The present invention offers significant advantages over the prior art. Specifically, as can be seen from the above technical solution, the present invention provides a pyrrole-based bisphosphonic acid carbazole polymer and a synthesis method. The bisphosphonic acid group is linked to form a conjugated structure via a pyrrole ring, which not only ensures the hole transport capability of the material but also allows for better regulation of the molecular dipole moment and interfacial properties. The bisphosphonic acid group structure also allows for a more stable bond with the substrate, improving the wettability and coverage of the perovskite solution. The substituents on the carbazole group or the carbon chain length between it and the phosphonic acid group can be freely varied as needed to adjust the solubility, stacking pattern, 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, enabling mass production under conventional conditions, meeting the needs of industrialization.

[0042] The bisphosphonic acid carbazole polymer described in this invention is used as a self-assembled monolayer in the hole transport layer of perovskite solar cells, resolving the problems of previous hole transport layer materials, such as difficulty in perovskite layer coverage and complex preparation processes. The conjugated structure formed by the pyrrole ring and the biscarbazole molecules in the molecule ensures the material's excellent hole transport capacity and photovoltaic performance. The terminal bisphosphonic acid group strengthens the bond with the substrate and improves the material's stability. The synthesis process and conditions for this type of molecule are relatively simple, making it suitable for large-scale industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 1 is a synthetic route diagram of the bisphosphonic acid carbazole polymer described in the embodiments of the present invention;

[0044] Figure 2 Schematic diagram of the battery structure using the bisphosphonic acid carbazole polymer described in an embodiment of the present invention.

[0045] The numbers in the figure are: 10, transparent conductive substrate; 20, hole transport layer; 30, perovskite light absorption layer; 40, electron transport layer; 50, top electrode. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0047] In the description of the present invention, unless otherwise specified, "plurality" means two or more; the terms "center", "longitudinal", "lateral", "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0048] This embodiment provides a pyrrole-based bisphosphonic acid carbazole polymer, the general structure of which is as follows:

[0049]

[0050] Wherein: R is hydrogen, methyl, methoxy, halogen, phenyl, halogenated benzyl, triphenylamine, etc.; the value of n is any integer between 2 and 6.

[0051] The polymer molecules provided in this embodiment are mainly used in the structure of perovskite cells. In the structure of inverse perovskite cells, the existing technology mainly uses poly (bis (4-phenyl) (2,4,6-trimethylphenyl) amine) (PTAA) as the hole transport layer material. However, due to its strong hydrophobicity, this material easily leads to poor wettability and coverage of the perovskite film, thereby reducing device performance and stability.

[0052] The conjugated structure formed by the pyrrole ring and the biscarbazole molecule in the polymer molecule of the embodiment of the present invention ensures the excellent hole transport ability and photovoltaic performance of the material; and the terminal bisphosphonic acid group strengthens the connection with the substrate and improves the stability of the material.

[0053] The principles and technical effects of the present invention are further illustrated below through specific examples and comparative examples. The chemical name of compound I-1 provided in Example 1 is 1-(9H-carbazol-3-yl)ethanone, and compounds II-1 to VII-1 are their intermediates or final products.

[0054] Example 1

[0055] See also Figure 1This embodiment provides a method for synthesizing a bisphosphonic acid carbazole polymer based on a pyrrole group, comprising the steps of:

[0056] Step 1: To a 150 ml round-bottom flask, add 2.302 g of compound I-1 (11 mmol), 0.5 g of aluminum chloride, and 0.6 ml of liquid bromine (11 mmol). Then, add 20 ml of ether. Place in an ice-water bath and react for 1 hour. After returning to room temperature, column chromatography separation yields 2.85 g of white solid, namely compound II-1, in a 90% yield.

[0057] Step 2: To a 150 ml round-bottom flask, add 2.75 g of compound II-1 (9.54 mmol), 0.33 g of tetrakis(dimethylamino)ethylene (5.72 mmol), and 50 ml of tetrahydrofuran. Heat to 70°C and stir for 1 hour. Purify by column chromatography to obtain 3.18 g of a white solid, compound III-1, in 80% yield.

[0058] Step 3: To a 100 ml round-bottom flask, add 3.03 g of compound III-1 (7.28 mmol) and 1.157 g of ammonium acetate (15 mmol), then add 45 ml of glacial acetic acid and stir to dissolve. Heat to 120 °C and reflux for 12 hours. Purify by column chromatography to obtain 1.1 g of a white solid, namely compound IV-1, with a yield of 38%.

[0059] Step 4: To a 100-ml round-bottom flask, add 0.99 g of compound IV-1 (2.5 mmol) and 17 ml of 1,2-dibromoethane. Dissolve the mixture, then add 0.192 g of tetrabutylammonium bromide (0.6 mmol) and 14 ml of 50 wt% potassium hydroxide solution. Stir and heat to 70°C for 12 hours. Purify by column chromatography to obtain 0.917 g of a white solid, compound V-1, in a 60% yield.

[0060] Step 5: Add 0.8 g of compound Ⅴ-1 (1.31 mmol) and 8 ml of triethyl phosphite to a 50 ml round-bottom flask, stir to dissolve, heat to 165 ° C and reflux for 20 hours, and purify by column chromatography to obtain 0.856 g of light yellow oil, namely compound Ⅵ-1, with a yield of 90%.

[0061] Step 6: Add 0.75 g of compound VI-1 (1.03 mmol) to a 250 ml round-bottom flask. After replacing the nitrogen atmosphere, add 25 ml of 1,4-dioxane and 8 ml of trimethylsilyl bromide. Stir and react at room temperature for 24 hours. Then, add 40 ml of methanol and continue the reaction for 8 hours. Finally, add 80 ml of deionized water and react for 12 hours. After the reaction, evaporate the solution and filter to obtain the final product, compound VII-1.

[0062] This embodiment also provides a method for preparing a perovskite solar cell, using the final product compound VII-1 obtained by the above synthesis method as a hole transport layer material, comprising the steps of:

[0063] Step 1: Provide a transparent conductive substrate 10, clean the substrate with ultrasonic cleaning using deionized water, acetone, and isopropyl alcohol in sequence, blow dry with nitrogen, and then treat the surface of the substrate with an ultraviolet ozone cleaner.

[0064] Step 2: NiO at a concentration of 30 mg / ml x The solution is spin-coated on the surface of the transparent conductive substrate 10 to prepare NiO x Then, the compound VII-1 synthesized by the above method was weighed as a self-assembled monomolecular material and prepared into a self-assembled monomolecular layer material solution with anhydrous methanol at a concentration of 0.5 mg / ml. The solution was spin-coated on NiO x The hole transport layer 20 is obtained after annealing.

[0065] Step 3: Weigh a certain amount of MAI, FAI, FABr, PbI2 and PbBr2 to prepare MA with a concentration of 1.0M 0.1 FA 0.9 Pb(I 0.85 Br 0.15 )3 perovskite precursor solution is spin-coated and annealed on the surface of the hole transport layer 20 to obtain the perovskite light absorbing layer 30.

[0066] Step 4: Evaporate a 20nm layer of C on the surface of the perovskite light absorbing layer 30 60 The electron transport layer 40 is obtained.

[0067] Step 5: Vacuum evaporation is used on the surface of the electron transport layer 40 at a vacuum degree of 5×10 -4 A 100 nm gold top electrode 50 was prepared under the conditions of Pa.

[0068] Comparative Example 1

[0069] This comparative example uses MeO-2PACz as a hole transport layer to prepare an inverse perovskite solar cell, including the following steps:

[0070] Step 1: Provide a transparent conductive substrate 10, clean the substrate with ultrasonic cleaning using deionized water, acetone, and isopropyl alcohol in sequence, blow dry with nitrogen, and then treat the surface of the substrate with an ultraviolet ozone cleaner.

[0071] Step 2: NiO at a concentration of 30 mg / ml x The solution is spin-coated on the surface of the transparent conductive substrate 10 to prepare NiO xThen weigh MeO-2PACz and prepare a SAM (Self-assembled Monolayer) solution with anhydrous methanol at a concentration of 0.5 mg / ml. Spin-coat it on the NiO x The hole transport layer 20 is obtained after annealing.

[0072] Step 3: Weigh a certain amount of MAI, FAI, FABr, PbI2 and PbBr2 to prepare MA with a concentration of 1.0M 0.1 FA 0.9 Pb(I 0.85 Br 0.15 )3 Perovskite precursor solution is spin-coated and annealed to obtain a perovskite light absorbing layer 30.

[0073] Step 4: Evaporate a 20nm layer of C on the surface of the perovskite light absorbing layer 60 The electron transport layer 40 is obtained.

[0074] Step 5: Vacuum evaporation is used on the electron transport surface at a vacuum degree of 5×10 -4 A 100 nm gold layer was prepared under the conditions of 100 nm Pa to obtain a top electrode 50, thereby completing the preparation of the perovskite solar cell.

[0075] A solar simulator was used to calibrate the intensity of a standard sun and to measure the area of ​​1.0 cm 2 The perovskite battery device obtained in the above embodiment and comparative example was subjected to long-term IV test, with the starting voltage set to 1.95V, the cut-off voltage set to 0V, the range set to 100mA, and the J of the device measured. SC (short-circuit current density), V OC (open circuit voltage), FF (fill factor) and PCE (conversion efficiency), the results are rounded to two decimal places, and the test results are shown in the following table;

[0076] Device <![CDATA[J SC (mA cm -2 )]]> <![CDATA[V OC (V)]]> FF(%) PCE(%) Example 1 20.78 1.23 84.33 21.55 Comparative Example 1 21.00 1.22 81.53 20.89

[0077] From the test data obtained in the experiment, it can be seen that Example 1 uses a self-assembled monolayer material of bisphosphonic acid carbazole based on a pyrrole group and applies it to modifying the hole transport layer of the perovskite solar cell, which improves the carrier transport capacity of the hole transport layer and the stability of the interface structure. Compared with the comparative example 1 in which MeO-2PACz material is used as the hole transport layer, the fill factor and photoelectric conversion efficiency of the battery device are greatly improved. The processes and conditions involved in the molecular synthesis route are relatively simple, and mass production can be achieved under conventional conditions, meeting the needs of industrialization.

[0078] The above embodiments are only preferred implementation modes of the present invention. It should be pointed out that for ordinary technicians in this technical field, various changes, modifications, replacements and deformations can be made to these embodiments without departing from the principles of the present invention. These technical solutions that are equivalent to the claims of the present invention all fall within the scope of protection of the present invention, and the scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A bisphosphonic acid carbazole polymer based on pyrrole groups, characterized in that: The general structural formula is as follows: ； In the formula: R is hydrogen, methyl, methoxy, halogen, phenyl, halogenated benzyl, or triphenylamine; and the value of n is any integer between 2 and 6.

2. A method for synthesizing a pyrrole-based bisphosphonic acid carbazole polymer, characterized in that: Including steps: S1: Compound Under the conditions of catalyst and liquid bromine, the compound is generated ; S2: Compound Under the action of tetrakis(dimethylamino)ethylene (TADE), the compound is generated. ; S3: Compound Reaction with ammonium acetate in glacial acetic acid to give compound ; S4: Compound Reacting with dibromoalkane under alkaline conditions to obtain compound ; S5: Compound After reacting with triethyl phosphite, the compound ; S6: Compound Dissolve in 1,4-dioxane and react with trimethylsilyl bromide under inert atmosphere; then add methanol to continue the reaction; finally add deionized water to react, filter and dry to obtain the compound ; Wherein R is hydrogen, methyl, methoxy, halogen, phenyl, halogenated benzyl, or triphenylamine; and the value of n is any integer between 2 and 6.

3. The synthesis method according to claim 2, characterized in that In step S1, the catalyst is AlCl3. Add AlCl3 and liquid bromine, then add ether, place in an ice-water bath to react for 1 hour, then cool to room temperature, and separate by column chromatography to obtain compound .

4. The synthesis method according to claim 2, characterized in that In step S2, tetrahydrofuran was added for dissolution, the temperature was raised to 70°C and stirred for 1 hour, and the compound was purified by column chromatography to obtain .

5. The synthesis method according to claim 2, characterized in that In step S3, the reaction temperature is 120° C. and the reaction time is 1 h. Compound 1 is obtained by column chromatography separation. .

6. The synthesis method according to claim 2, characterized in that In step S4, tetrabutylammonium bromide and 50 wt% potassium hydroxide solution were added; the mixture was stirred and heated to 70°C for 12 hours, and the compound was separated by column chromatography. .

7. The synthesis method according to claim 2, characterized in that In step S5, the reaction temperature is 165° C. and the reaction time is 20 h. Compound .

8. The synthesis method according to claim 2, characterized in that In step S6, the inert atmosphere is nitrogen, and the reaction is carried out at room temperature under nitrogen for 24 hours. Methanol is added and the reaction is continued for 8 hours. Deionized water is added and the reaction is continued for 12 hours. The solution is evaporated and filtered to obtain the compound .

9. A method for preparing a perovskite solar cell, characterized in that: Using the pyrrole-based bisphosphonic acid carbazole polymer according to any one of claims 1 to 8 as a hole transport layer comprises the steps of: A transparent conductive substrate is provided, and NiO is formed on the transparent conductive substrate. x The bisphosphonic acid carbazole polymer material based on the pyrrole group is dissolved in anhydrous methanol to obtain a self-assembled monolayer solution, which is coated on the NiO x A perovskite light absorbing layer, an electron transport layer and a top electrode are sequentially prepared on the hole transport layer.

10. The method for preparing a perovskite solar cell according to claim 9, wherein: The concentration of the self-assembled monolayer solution is 0.1-10 mg / mL. x The annealing temperature on the layer is 60~100℃, and the annealing time is 2~10min.

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