Perovskite solar cell based on phenylhydrazine multifunctional molecular additive and preparation method and application thereof

Abstract

A multifunctional molecular additive based on phenylhydrazine for perovskite solar cells, its preparation method, and its application; the multifunctional molecular additive based on phenylhydrazine has the structures shown in formulas I to III; wherein the amide group can combine with PbI2 to form an adduct, and with free I... ‑ Competition with Pb 2+ This combination increases the reaction barrier during perovskite growth, thereby reducing the crystallization rate and effectively minimizing non-radiative convergence, thus improving photoelectric conversion efficiency; F atoms can modulate the dipole moment of the additive and interact with charged A atoms. + The groups form hydrogen bonds, thus the additive successfully stitches up the defects at the perovskite grain boundaries and releases the grain boundary stress, thereby obtaining low Young's modulus and high mechanical flexibility. At the same time, the additive can weaken the interaction between charge carriers and longitudinal optical phonons and promote the extraction and transport of charge carriers. More importantly, the additive with strong molecular dipoles can better improve the efficiency and stability of perovskite solar cells.

Description

Technical Field

[0001] This invention relates to the field of perovskite solar cell technology, and more specifically, to a multifunctional molecular additive for perovskite solar cells based on phenylhydrazine, its preparation method, and its application. Background Technology

[0002] With the continuous development of human society, the demand for energy is increasing. Traditional energy sources, such as oil, natural gas, and coal, are non-renewable energy sources; not only are their reserves dwindling, but they also cause significant environmental pollution. Therefore, vigorously developing renewable, green, and clean energy is extremely urgent and important. Solar energy is particularly prominent, as it is inexhaustible and does not impact the environment; its application research has received increasing attention. Developing clean, pollution-free, and abundant solar energy has become a hot topic of research for scientists. Organic-inorganic halide perovskite materials have attracted widespread attention in the photovoltaic field due to their excellent photoelectric properties. However, the presence of lead, a heavy metal harmful to the environment and human health, in perovskite materials hinders their commercialization. Tin, with the same outer electron structure and similar ionic radius as lead, can form the same type of three-dimensional perovskite structure and has a more ideal optical band gap, making it the most promising alternative to lead-based perovskites and capable of achieving better photovoltaic performance.

[0003] Currently, tin-based perovskite solar cells have achieved record efficiencies exceeding 14%. However, research on tin-based perovskite solar cells also faces numerous severe challenges. One major challenge is the inherent susceptibility of tin-based perovskite materials to oxidation, generating Sn vacancies and leading to significant nonradiative recombination losses and voltage drops. Furthermore, the Ig content in tin-based perovskite materials... - Furthermore, the organic cations at the A site are highly volatile during the thermal annealing process, making the crystallization process of tin-based perovskite films more difficult to control, resulting in poorer film morphology and the formation of disordered grains that generate many three-dimensional defects. These defects facilitate the corrosion of oxygen and moisture, greatly reducing the performance and stability of the device. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a multifunctional molecular additive for perovskite solar cells based on phenylhydrazine, its preparation method, and its application. The multifunctional molecular additive for perovskite solar cells based on phenylhydrazine provided by this invention contains a phenylhydrazine group that acts as a reducing agent, effectively inhibiting Sn. 2+Oxidation reduces p-type self-doping in tin-based perovskites, passivates surface defects in perovskite films, and improves the stability of tin-based perovskite solar cells. F atoms can adjust the dipole moment of additives and form hydrogen bonds with charged A-site organic cations, bridging defects at perovskite grain boundaries. At the same time, they can effectively control the crystallization process of the film and regulate the crystallization kinetics of tin-based perovskites. More importantly, among the molecules formed by the combination of the two, additives with strong molecular dipoles can better improve the efficiency and stability of tin-based perovskite solar cells.

[0005] This invention provides a multifunctional molecular additive for perovskite solar cells based on phenylhydrazine, having the structures shown in Formulas I to III:

[0006]

[0007] This invention also provides a method for preparing a multifunctional molecular additive based on phenylhydrazine for perovskite solar cells as described in the above technical solution, comprising the following steps:

[0008] Bromophenylhydrazine was dissolved in a mixed solution of toluene and ethanol with 2,6-difluorophenylboronic acid, Pd(P(Ph)3)4, and K2CO3 and reacted in an inert gas atmosphere. After cooling, water was added to the reaction mixture, and the reaction mixture was extracted with dichloromethane. Finally, the mixture was dried, desolventized, and purified to obtain a multifunctional molecular additive for perovskite solar cells based on phenylhydrazine.

[0009] The bromophenylhydrazine is 4-bromophenylhydrazine, 3-bromophenylhydrazine, or 2-bromophenylhydrazine.

[0010] Preferably, the molar ratio of bromophenylhydrazine, 2,6-difluorophenylboronic acid, Pd(P(Ph)3)4, and K2CO3 is 10:(8-12):(0.1-1):(40-60);

[0011] The volume ratio of toluene to ethanol is (3-5):1.

[0012] Preferably, the reaction temperature is 85℃~95℃ and the time is 6h~10h.

[0013] This invention also provides the application of a molecular additive in the preparation of tin-based perovskite solar cells, wherein the molecular additive is a multifunctional molecular additive based on phenylhydrazine for perovskite solar cells as described in the above technical solution.

[0014] Preferably, the method for fabricating the perovskite solar cell includes the following steps:

[0015] Step 1: Prepare a tin-based perovskite precursor solution containing a multifunctional molecular additive based on phenylhydrazine for perovskite solar cells;

[0016] Step 2: Anneal the substrate, wherein the substrate contains a hole transport layer;

[0017] Step 3: Coat the above tin-based perovskite precursor solution onto the above hole transport layer and heat it to generate a perovskite thin film.

[0018] Step 4: Form an electron transport layer on the perovskite thin film;

[0019] Step 5: Form an electrode layer on the electron transport layer to obtain a perovskite solar cell.

[0020] Preferably, in the perovskite precursor solution containing the multifunctional molecular additive for perovskite solar cells based on phenylhydrazine, the general formula of the perovskite material is ABX3, where A is CH3NH3. + CH(NH2)2 + Cs + and Rb + One or more of them, where B is Sn 2+ X is Cl - ,Br - and I - One or more of the following; the solvent is selected from one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolinone, dimethylacetamide, N,N-dimethylpropenylurea, acetonitrile and 2-mercaptoethanol.

[0021] Preferably, in the perovskite precursor solution containing the multifunctional molecular additive for perovskite solar cells based on phenylhydrazine, the ratio of the total molar amount of the active component to the molar amount of the multifunctional molecular additive for perovskite solar cells based on phenylhydrazine is 100:(0.1~2).

[0022] Preferably, the hole transport layer is a p-type inorganic semiconductor or a p-type organic semiconductor;

[0023] The electron transport layer is an n-type inorganic semiconductor or an n-type organic semiconductor;

[0024] The material of the back electrode is Au, Ag, or a low-temperature carbon electrode.

[0025] Preferably, the thickness of the perovskite film is 400 nm to 700 nm.

[0026] This invention provides a multifunctional molecular additive for perovskite solar cells based on phenylhydrazine, its preparation method, and its application. The multifunctional molecular additive for perovskite solar cells based on phenylhydrazine has the structures shown in Formulas I to III. The preparation method includes the following steps: dissolving bromophenylhydrazine with 2,6-difluorophenylboronic acid, Pd(P(Ph)3)4, and K2CO3 in a mixed solution of toluene and ethanol, and reacting under an inert gas atmosphere; after cooling, adding water to the reaction mixture, extracting the reaction mixture with dichloromethane, and finally drying, desolventizing, and purifying sequentially to obtain the multifunctional molecular additive for perovskite solar cells based on phenylhydrazine; wherein the bromophenylhydrazine is 4-bromophenylhydrazine, 3-bromophenylhydrazine, or 2-bromophenylhydrazine. Compared with the prior art, the multifunctional molecular additive for perovskite solar cells based on phenylhydrazine provided by this invention contains a phenylhydrazine group that acts as a reducing agent, effectively inhibiting Sn. 2+ Oxidation reduces p-type self-doping in tin-based perovskites, passivates surface defects in perovskite films, and improves the stability of tin-based perovskite solar cells. F atoms can adjust the dipole moment of additives and form hydrogen bonds with charged A-site organic cations, bridging defects at perovskite grain boundaries. At the same time, they can effectively control the crystallization process of the film and regulate the crystallization kinetics of tin-based perovskites. More importantly, among the molecules formed by the combination of the two, additives with strong molecular dipoles can better improve the efficiency and stability of tin-based perovskite solar cells.

[0027] Meanwhile, the preparation method provided by this invention is simple, the conditions are mild and easy to control, the raw materials are readily available and the cost is low, and it has broad application prospects. Attached Figure Description

[0028] Figure 1 The images show the UV spectra of tin-based perovskite films prepared without additives and with different additives.

[0029] Figure 2 The fluorescence spectra of tin-based perovskite films prepared without additives and with different additives are shown.

[0030] Figure 3 The fluorescence lifetime spectra of tin-based perovskite films prepared without additives and with different additives are shown.

[0031] Figure 4 This is a comparison of the stability of tin-based perovskite solar cells prepared without additives and with different additives. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] This invention provides a multifunctional molecular additive for perovskite solar cells based on phenylhydrazine, having the structures shown in Formulas I to III:

[0034]

[0035] In this invention, the perovskite solar cell based on phenylhydrazine multifunctional molecular additives of the structure shown in Formula I has a stronger molecular dipole compared to the other two structures of perovskite solar cells based on phenylhydrazine multifunctional molecular additives. Since the higher the maximum electrostatic potential (φmax) of the additive, the stronger the bonding strength between the perovskite and the passivating agent, and the lower the minimum electrostatic potential (φmin) of the additive, the stronger the bonding strength between the carrier transport layer and the passivated perovskite layer, the stronger the interaction between the additive with higher molecular polarity and the perovskite, and the fewer the corresponding device defects. Therefore, the first molecule performs better in improving the efficiency and stability of tin-based perovskite solar cells.

[0036] This invention also provides a method for preparing a multifunctional molecular additive based on phenylhydrazine for perovskite solar cells as described in the above technical solution, comprising the following steps:

[0037] Bromophenylhydrazine was dissolved in a mixed solution of toluene and ethanol with 2,6-difluorophenylboronic acid, Pd(P(Ph)3)4, and K2CO3 and reacted in an inert gas atmosphere. After cooling, water was added to the reaction mixture, and the reaction mixture was extracted with dichloromethane. Finally, the mixture was dried, desolventized, and purified to obtain a multifunctional molecular additive for perovskite solar cells based on phenylhydrazine.

[0038] The bromophenylhydrazine is 4-bromophenylhydrazine, 3-bromophenylhydrazine, or 2-bromophenylhydrazine.

[0039] In this invention, the bromophenylhydrazine is 4-bromophenylhydrazine, 3-bromophenylhydrazine, or 2-bromophenylhydrazine, preferably 4-bromophenylhydrazine. This invention does not impose any special restrictions on the source of the bromophenylhydrazine and other raw materials such as 2,6-difluorophenylboronic acid, Pd(P(Ph)3)4, K2CO3, toluene, ethanol, etc., and commercially available products well known to those skilled in the art can be used.

[0040] In this invention, the molar ratio of bromophenylhydrazine, 2,6-difluorophenylboronic acid, Pd(P(Ph)3)4, and K2CO3 is preferably 10:(8-12):(0.1-1):(40-60), more preferably 10:10:(0.4-0.6):(45-55). In this invention, the volume ratio of toluene to ethanol is preferably (3-5):1.

[0041] In this invention, the inert gas atmosphere is preferably a nitrogen atmosphere; the reaction process is preferably carried out under stirring conditions, the reaction temperature is preferably 85℃~95℃, more preferably 90℃, and the reaction time is preferably 6h~10h, more preferably 8h.

[0042] In this invention, the cooling temperature is preferably 20℃~30℃; the number of times the reaction mixture is extracted with dichloromethane is preferably 2 to 4 times; the drying method is preferably drying on anhydrous magnesium sulfate; the solvent removal method is preferably removing the solvent under vacuum to obtain powder; the purification process is preferably as follows: the crude product is purified by silica gel (volume ratio PE:DCM = 10:1) column chromatography to obtain a multifunctional molecular additive for perovskite solar cells based on phenylhydrazine.

[0043] The preparation method provided by this invention is simple, with mild and easily controllable conditions, and the raw materials are readily available and low in cost, thus having broad application prospects.

[0044] This invention also provides the application of a molecular additive in the preparation of tin-based perovskite solar cells, wherein the molecular additive is a multifunctional molecular additive based on phenylhydrazine for perovskite solar cells as described in the above technical solution.

[0045] In this invention, the method for preparing the perovskite solar cell preferably includes the following steps:

[0046] Step 1: Prepare a tin-based perovskite precursor solution containing a multifunctional molecular additive based on phenylhydrazine for perovskite solar cells;

[0047] Step 2: Anneal the substrate, wherein the substrate contains a hole transport layer;

[0048] Step 3: Coat the above tin-based perovskite precursor solution onto the above hole transport layer and heat it to generate a perovskite thin film.

[0049] Step 4: Form an electron transport layer on the perovskite thin film;

[0050] Step 5: Form an electrode layer on the electron transport layer to obtain a perovskite solar cell.

[0051] In this invention, the perovskite precursor solution containing the multifunctional molecular additive for perovskite solar cells based on phenylhydrazine preferably has the general formula ABX3, where A is CH3NH3. + CH(NH2)2 + Cs + and Rb + One or more of them, where B is Sn 2+ X is Cl - ,Br - and I - One or more of the following; the present invention does not have any special restrictions on the source of the perovskite material, and commercially available products well known to those skilled in the art can be used.

[0052] In this invention, the solvent in the perovskite precursor solution containing the multifunctional molecular additive for perovskite solar cells based on phenylhydrazine is preferably selected from one or more 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), and 2-mercaptoethanol (2-ME). This invention does not impose any particular restrictions on the source of the solvent for the perovskite precursor solution; commercially available products well known to those skilled in the art can be used.

[0053] In this invention, the ratio of the total molar amount of the active component to the molar amount of the multifunctional molecular additive based on phenylhydrazine for perovskite solar cells in the perovskite precursor solution is preferably 100:(0.1-2).

[0054] In this invention, the hole transport layer is preferably a p-type inorganic semiconductor or a p-type organic semiconductor; wherein, the material of the p-type inorganic semiconductor or p-type organic semiconductor includes one or more of the following: poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), 4-butyl-N,N-diphenylaniline homopolymer (Ploy-TPD), polyvinylcarbazole (PVK), CuI, and CuSCN; the present invention does not have any special restrictions on its source.

[0055] In this invention, the electron transport layer is preferably an n-type inorganic semiconductor or an n-type organic semiconductor; wherein, the material of the n-type inorganic semiconductor or n-type organic semiconductor includes C. 60One or more of PCBM, TiO2, SnO2, ZnO, and ZnO-ZnS; the present invention does not have any special restrictions on their sources.

[0056] In this invention, the material of the back electrode is preferably Au, Ag, or a low-temperature carbon electrode.

[0057] The tin-based perovskite solar cell provided by this invention includes a conductive substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a back electrode. The perovskite light-absorbing layer is prepared by introducing a phenylhydrazine-based multifunctional molecular additive, as described in the above-described method, to form a perovskite thin film. In this invention, the thickness of the perovskite thin film is preferably 400 nm to 700 nm.

[0058] This invention provides a multifunctional molecular additive for perovskite solar cells based on phenylhydrazine, its preparation method, and its application. The multifunctional molecular additive for perovskite solar cells based on phenylhydrazine has the structures shown in Formulas I to III. The preparation method includes the following steps: dissolving bromophenylhydrazine with 2,6-difluorophenylboronic acid, Pd(P(Ph)3)4, and K2CO3 in a mixed solution of toluene and ethanol, and reacting under an inert gas atmosphere; after cooling, adding water to the reaction mixture, extracting the reaction mixture with dichloromethane, and finally drying, desolventizing, and purifying sequentially to obtain the multifunctional molecular additive for perovskite solar cells based on phenylhydrazine; wherein the bromophenylhydrazine is 4-bromophenylhydrazine, 3-bromophenylhydrazine, or 2-bromophenylhydrazine. Compared with the prior art, the multifunctional molecular additive for perovskite solar cells based on phenylhydrazine provided by this invention contains a phenylhydrazine group that acts as a reducing agent, effectively inhibiting Sn. 2+ Oxidation reduces p-type self-doping in tin-based perovskites, passivates surface defects in perovskite films, and improves the stability of tin-based perovskite solar cells. F atoms can adjust the dipole moment of additives and form hydrogen bonds with charged A-site organic cations, bridging defects at perovskite grain boundaries. At the same time, they can effectively control the crystallization process of the film and regulate the crystallization kinetics of tin-based perovskites. More importantly, among the molecules formed by the combination of the two, additives with strong molecular dipoles can better improve the efficiency and stability of tin-based perovskite solar cells.

[0059] Meanwhile, the preparation method provided by this invention is simple, the conditions are mild and easy to control, the raw materials are readily available and the cost is low, and it has broad application prospects.

[0060] To further illustrate the present invention, the following embodiments will be described in detail.

[0061] Synthesis example 1

[0062] The reaction formula is as follows:

[0063]

[0064] The specific synthesis method is as follows:

[0065] 10 mmol of 4-bromophenylhydrazine, 10 mmol of 2,6-difluorophenylboronic acid, 0.5 mmol of Pd(P(Ph)3)4, and 50 mmol of K2CO3 were dissolved in a mixture of 120 mL of toluene and 30 mL of ethanol. The mixture was stirred continuously at 90 °C for 8 h under a nitrogen atmosphere. After cooling to room temperature, 200 mL of deionized water was added to the mixture. The reaction mixture was then extracted three times with 100 mL of dichloromethane, 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 (PE:DCM = 10:1, v / v) to obtain the final product, a multifunctional molecular additive for perovskite solar cells based on phenylhydrazine, denoted as compound A.

[0066]

[0067] Synthesis example 2

[0068] The reaction formula is as follows:

[0069]

[0070] The specific synthesis method is as follows:

[0071] 10 mmol of 3-bromophenylhydrazine, 10 mmol of 2,6-difluorophenylboronic acid, 0.5 mmol of Pd(P(Ph)3)4, and 50 mmol of K2CO3 were dissolved in a mixed solution of 120 mL toluene and 30 mL ethanol. The mixture was stirred continuously at 90 °C for 8 h under a nitrogen atmosphere. After cooling to room temperature, 200 mL of deionized water was added to the mixture. The reaction mixture was then extracted three times with 100 mL of dichloromethane, 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 (PE:DCM = 10:1, v / v) to obtain the final product, a multifunctional molecular additive for perovskite solar cells based on phenylhydrazine, denoted as compound B.

[0072]

[0073] Synthesis example 3

[0074] The reaction formula is as follows:

[0075]

[0076] The specific synthesis method is as follows:

[0077] 10 mmol of 2-bromophenylhydrazine, 10 mmol of 2,6-difluorophenylboronic acid, 0.5 mmol of Pd(P(Ph)3)4, and 50 mmol of K2CO3 were dissolved in a mixture of 120 mL of toluene and 30 mL of ethanol. The mixture was stirred continuously at 90 °C for 8 h under a nitrogen atmosphere. After cooling to room temperature, 200 mL of deionized water was added to the mixture. The reaction mixture was then extracted three times with 100 mL of dichloromethane, 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 (PE:DCM = 10:1, v / v) to obtain the final product, a multifunctional molecular additive for perovskite solar cells based on phenylhydrazine, denoted as compound C.

[0078]

[0079] Example 1

[0080] Step 1: Clean the transparent conductive glass, specifically by ultrasonic cleaning with detergent, deionized water, acetone and anhydrous ethanol respectively, and then drying it with a nitrogen gun; the ultrasonic cleaning power is 100Hz and the ultrasonic cleaning time is 15min.

[0081] Step 2: Deposit a hole transport layer on the conductive glass surface by spin coating. Specifically, a hole transport layer solution with a concentration of 65 mg / mL prepared by PEDOT:PSS is dropped onto the conductive glass in Step 1 and spin-coated at 5000 rpm for 50 s to obtain a hole transport layer with a thickness of approximately 20 nm.

[0082] Step 3: Prepare a tin-based perovskite light-absorbing layer on the upper surface of the hole transport layer, specifically including:

[0083] Iodine dispersed in 0.85 M DMSO was reacted with excess Sn for 12 h to obtain a SnI2 solution. 1 mL of this solution was filtered through a 0.45 μm PTFE filter. Subsequently, 0.7225 mmol FAI, 0.1225 mmol PEABr, 0.085 mmol SnF2, and 0.017 mmol of molecular additive compound A (at this point, the ratio of the total molar amount of the active component in the perovskite precursor solution to the molar amount of the molecular additive in the perovskite precursor solution was 100:2) were mixed with the above solution and stirred for 2 h. Finally, the resulting solution was filtered again through a 0.45 μm PTFE filter to obtain a tin-based perovskite precursor solution.

[0084] Take 18 μL of the above tin-based perovskite precursor solution and spin-coat it onto the surface of the hole transport layer at 5000 rpm for 80 s. At 50 s, spin-coat 800 μL of the antisolvent chlorobenzene. At this time, the perovskite film can be observed to turn dark brown. Then, anneal the above substrate at 80 °C for 10 min. The film turns dark black.

[0085] Step 4: Deposit an electron transport layer C on the surface of the perovskite layer using vacuum evaporation. 60 The evaporation is carried out under a vacuum of 5×10⁻⁶. -4 The process was carried out under Pa conditions, with an evaporation rate of 0.15 A / s and a thickness of approximately 20 nm.

[0086] Step 5: Deposit a hole blocking layer (BCP) on the surface of the electron transport layer using a vacuum evaporation method. The evaporation is performed at a vacuum level of 5 × 10⁻⁶. -4 The process was carried out under Pa conditions, with an evaporation rate of 0.2 A / s and a thickness of approximately 8 nm.

[0087] Step 6: Fabricate a metal electrode on the upper surface of the hole-blocking layer using PVD. In a metal evaporation chamber, form a silver electrode with a thickness of 80 nm to 100 nm on the surface of the electron transport layer opposite to the perovskite light-absorbing layer using a thermal evaporation process; this electrode serves as the metal cathode. The vacuum level of the evaporation chamber is 5 × 10⁻⁶. -4 Pa, with an evaporation rate of 2 A / s. This ultimately yielded a tin-based perovskite solar cell.

[0088] Example 2

[0089] The difference between this embodiment and Example 1 is that 0.017 mmol of compound B was added to the perovskite precursor solution in step 3 and stirred thoroughly to dissolve it. The rest of the preparation methods and parameters are the same as in Example 1.

[0090] Example 3

[0091] The difference between this embodiment and Example 1 is that 0.017 mmol of compound C was added to the perovskite precursor solution in step 3 and stirred thoroughly to dissolve it. The rest of the preparation methods and parameters are the same as in Example 1.

[0092] Example 4

[0093] The difference between this embodiment and Example 1 is that in step 3, 0.0085 mmol of compound A is added to the perovskite precursor solution (at this time, the ratio of the total molar amount of active components in the perovskite precursor solution to the molar amount of molecular additives in the perovskite precursor solution is 100:1), and the solution is thoroughly stirred and dissolved. The remaining preparation methods and parameters are the same as in Example 1.

[0094] Example 5

[0095] The difference between this embodiment and Example 1 is that in step 3, 0.00085 mmol of compound A is added to the perovskite precursor solution (at this time, the ratio of the total molar amount of active components in the perovskite precursor solution to the molar amount of molecular additives in the perovskite precursor solution is 100:0.1), and the solution is stirred and dissolved thoroughly. The remaining preparation methods and parameters are the same as in Example 1.

[0096] Comparative Example 1

[0097] The difference between this embodiment and Example 1 is that no additives were added to the perovskite precursor solution in step 3, while the rest of the preparation methods and parameters remained the same as in Example 1.

[0098] Comparative Example 2

[0099] The difference between this comparative example and Example 1 is that 0.017 mmol of phenylhydrazine and 0.017 mmol of 1,3-difluorobenzene were added to the perovskite precursor solution in step 3. The rest of the preparation methods and parameters are the same as in Example 1.

[0100] Performance testing:

[0101] See Figures 1-4 And Table 1.

[0102] Figures 1-3 This characterizes the optical properties of tin-based perovskite thin films in the absence of additives and with the addition of different additives. Figure 1 The ultraviolet spectrum shows a slight red shift in the absorption peak of the tin-based perovskite film after additive treatment. This is mainly because the F atoms can adjust the dipole moment of the additive and form hydrogen bonds with charged A-site organic cations, thus bridging defects at the perovskite grain boundaries. Simultaneously, it effectively controls the crystallization process of the film, reducing pores and increasing the crystal size of the perovskite. Meanwhile, the fluorescence spectrum of the perovskite film after additive treatment (e.g., ...) Figure 2 The emission peak and fluorescence lifetime (e.g.) Figure 3 Both showed significant improvements, further demonstrating that the phenylhydrazine group contained in this molecule, acting as a reducing agent, can effectively inhibit Sn. 2+ The oxidation of tin-based perovskites reduces p-type self-doping, passivates surface defects in perovskite films, and reduces non-radiative recombination. At the same time, F atoms can adjust the dipole moment of the additive and form hydrogen bonds with charged FA+ groups. Perovskite films treated with A-molecule additives, which have higher molecular dipoles, have the highest fluorescence intensity and fluorescence lifetime.

[0103] Table 1 Comparison of performance parameters of perovskite solar cells with and without different additives.

[0104] Serial Number Voc(V) <![CDATA[Jsc(mA / cm 2 )]]> FF (%) PCE (%) Example 1 0.75 21.7 75.2 12.24 Example 2 0.73 21.5 75.3 11.82 Example 3 0.74 21.4 75.5 11.87 Example 4 0.76 21.6 75.5 12.39 Example 5 0.74 21.8 75.1 12.11 Comparative Example 1 0.62 20.3 72.3 9.10 Comparative Example 2 0.65 20.5 73.3 9.77

[0105] Figure 4 Table 1 shows a comparison of the stability of tin-based perovskite solar cells prepared without additives and with different additives. As can be seen from Table 1, the open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency of the tin-based perovskite thin-film solar cells treated with additives are significantly improved. The stability comparison chart of perovskite solar cells shows that the stability of the perovskite solar cells treated with additives can still maintain more than 95% of the initial value after 500 hours, while the untreated solar cells decay faster. This is because the phenylhydrazine group, as a reducing agent, can effectively suppress the degradation of Sn. 2+ The oxidation of tin-based perovskites reduces p-type self-doping, passivates surface defects in perovskite films, and improves the stability of tin-based perovskite solar cells. Furthermore, because the A-molecule additive has a stronger molecular dipole, the PCE value and stability of the tin-based perovskite film treated with A-molecule are further improved.

[0106] Compared to Comparative Example 2, when equal amounts of 1,3-difluorobenzene and phenylhydrazine were added, the battery efficiency and stability increased slightly, but the improvement was not significant compared to Examples 1-3, which again demonstrates the synergistic effect between the F group and phenylhydrazine.

[0107] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multifunctional molecular additive for perovskite solar cells based on phenylhydrazine, characterized in that, It has the structure shown in Equations I to III:

2. A method for preparing a perovskite solar cell based on a multifunctional molecular additive of phenylhydrazine as described in claim 1, characterized in that, Includes the following steps: Bromophenylhydrazine was dissolved in a mixed solution of toluene and ethanol with 2,6-difluorophenylboronic acid, Pd(P(Ph)3)4, and K2CO3 and reacted in an inert gas atmosphere. After cooling, water was added to the reaction mixture, and the reaction mixture was extracted with dichloromethane. Finally, the mixture was dried, desolventized, and purified to obtain a multifunctional molecular additive for perovskite solar cells based on phenylhydrazine. The bromophenylhydrazine is 4-bromophenylhydrazine, 3-bromophenylhydrazine, or 2-bromophenylhydrazine.

3. The preparation method according to claim 2, characterized in that, The molar ratio of bromophenylhydrazine, 2,6-difluorophenylboronic acid, Pd(P(Ph)3)4, and K2CO3 is 10:(8-12):(0.1-1):(40-60); The volume ratio of toluene to ethanol is (3-5):

1.

4. The preparation method according to claim 2, characterized in that, The reaction is carried out at a temperature of 85℃ to 95℃ for a duration of 6 to 10 hours.

5. The application of a molecular additive in the preparation of tin-based perovskite solar cells, characterized in that, The molecular additive is the phenylhydrazine-based multifunctional molecular additive for perovskite solar cells as described in claim 1.

6. The application according to claim 5, characterized in that, The method for preparing the perovskite solar cell includes the following steps: Step 1: Prepare a tin-based perovskite precursor solution containing a multifunctional molecular additive based on phenylhydrazine for perovskite solar cells; Step 2: Anneal the substrate, wherein the substrate contains a hole transport layer; Step 3: Coat the above tin-based perovskite precursor solution onto the above hole transport layer and heat it to generate a perovskite thin film. Step 4: Form an electron transport layer on the perovskite thin film; Step 5: Form an electrode layer on the electron transport layer to obtain a perovskite solar cell.

7. The application according to claim 6, characterized in that, In the perovskite precursor solution containing the multifunctional molecular additive for perovskite solar cells based on phenylhydrazine, the general formula of the perovskite material is ABX3, where A is CH3NH3. + CH(NH2)2 + Cs + and Rb + One or more of them, where B is Sn 2+ X is Cl - ,Br - and I - One or more of the following; the solvent is selected from one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolinone, dimethylacetamide, N,N-dimethylpropenylurea, acetonitrile and 2-mercaptoethanol.

8. The application according to claim 6, characterized in that, In the perovskite precursor solution containing the multifunctional molecular additive for perovskite solar cells based on phenylhydrazine, the ratio of the total molar amount of the active component to the molar amount of the multifunctional molecular additive for perovskite solar cells based on phenylhydrazine is 100:(0.1~2).

9. The application according to claim 6, characterized in that, The hole transport layer is a p-type inorganic semiconductor or a p-type organic semiconductor; The electron transport layer is an n-type inorganic semiconductor or an n-type organic semiconductor; The material of the back electrode is Au, Ag, or a low-temperature carbon electrode.

10. The application according to claim 5, characterized in that, The thickness of the perovskite thin film is 400 nm to 700 nm.

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