Method for improving quality of perovskite thin film, perovskite thin film and solar cell

Abstract

The invention relates to a method for improving the quality of a perovskite thin film, the perovskite thin film and a solar cell, and the method specifically comprises the following steps: introducing aromatic amine or N-containing heterocyclic ring and alpha, beta-unsaturated aldehyde ketone additive into a precursor solution of organic halide, carrying out in-situ Michael addition reaction on the additive, firstly preparing solution components through the additive, and then preparing the organic halide precursor solution; side reaction in the solution is avoided, the irreversible degradation process of the precursor solution is effectively inhibited, and the storage stability of the precursor solution of the organic halide is improved; besides, through an additive and an in-situ Michael addition reaction, the release rate of organic halide is effectively delayed, rapid reaction between the organic halide and metal halide is inhibited, the perovskite nucleation / crystallization process is regulated and controlled, and reaction product functional groups finally reserved on the surface / grain boundary of the thin film can effectively passivate uncoordinated lead ions or iodine defects, so that the performance of the thin film is improved. Therefore, the high-quality perovskite thin film and a corresponding device are obtained.

Description

Technical Field

[0001] The present disclosure relates to the field of perovskite solar cells, and in particular to a method for preparing solar cells by regulating perovskite crystallization based on an in-situ Michael addition reaction. Background Art

[0002] In recent years, the energy conversion efficiency of inorganic-organic hybrid perovskite solar cells has developed from 3.8% in 2009 to more than 26% now. Despite this, the energy conversion efficiency of perovskite solar cells is still somewhat lower than the theoretical limit efficiency, and its long-term stability has become the main obstacle to its industrial development. First, as a colloidal dispersion, the conditions of the precursor solution will affect the nucleation and growth process of the film, and then affect the surface morphology, carrier transport properties and defect density of the final film, resulting in large differences in device performance. The efficiency of perovskite solar cells is highly dependent on the quality of the perovskite film. Impurities in the precursor solution can cause the formation of film defects, leading to non-radiative recombination of carriers, thereby reducing device efficiency. In addition, in order to better regulate the crystallization of perovskites, the two-step continuous deposition method for preparing perovskites has been widely studied, which can effectively regulate the perovskite nucleation and crystallization process. However, in the two-step preparation process, there is a problem of incomplete reaction between organic halides (such as formamidine hydroiodide FAI or MAI) and metal halides (such as PbI2), and excess metal halides will affect device efficiency and stability.

[0003] The organic components in the perovskite precursor solution are unstable. As the stirring time increases, they may undergo chemical reactions due to external factors such as light and high temperature (Chin. J. Chem. 2023, 41, 2730-2745). During the preparation of the perovskite precursor solution, FA with lower activation energy + Cations easily react with amines to form complexes, which leads to changes in the perovskite precursor solution (ACS Energy Lett. 2021, 6, 3425-3434). Methylammonium chloride (MACl) is a commonly used additive to stabilize the perovskite α-FAPbI3 phase and regulate crystallization, but its low acid dissociation constant makes it easy to deprotonate and react with FAI to form N-methylformamidine iodide (MFAI) (J.Am.Chem.Soc.2023, 145, 27900-27910). In addition, MFAI can also be formed by deprotonating FA and MACl. +Reaction generation (ACS Energy Lett. 2022, 7, 481-489). During the preparation of perovskite films, FAI easily escapes from the surface of the film, resulting in the formation of surface defects (Nature, 2022, 611, 278-283). Formamidine hydroiodide (FAI) will be deprotonated in the precursor solution, and then the formamidine molecules will form a by-product s-triazine through addition elimination, and its content will also increase with the aging time of the solution (Solar RRL, 2021, 5, 2000715). In addition, the side reactions occurring in the precursor solution cause many unfavorable impurities to be generated in the solution. The impurities in the precursor solution will cause the formation of film defects, resulting in non-radiative recombination of carriers, thereby reducing the device efficiency.

[0004] Additive engineering is widely used to improve the defects of passivated perovskite films, and can effectively regulate the reaction rate of metal halides and organic halides to improve device performance. Therefore, solving the stability of precursors in solution and regulating and managing surface and deep energy level defects caused by insufficient coordination of lead ions during the crystallization process are crucial for manufacturing efficient and stable perovskite solar cells. Summary of the invention

[0005] In view of this, the present disclosure provides a method for improving the quality of perovskite films, which can improve the stability of perovskite precursor solutions under ambient conditions and at 60°C, and adjust the solution components by additives to avoid side reactions in the solution, thereby effectively inhibiting the irreversible degradation process of the precursor solution; in addition, the method prepares high-quality perovskite films by modulating the reaction rate between metal halides and organic halides, thereby obtaining high-performance perovskite devices.

[0006] The core of the disclosed method is to introduce aromatic amine or N-containing heterocyclic and α, β-unsaturated aldehyde ketone additives into the precursor solution of organic halides, wherein the α, β-unsaturated aldehyde ketone can react with the deprotonated amine molecules in the precursor solution to block the self-addition elimination reaction of FA to generate s-triazine, or FA + The cation reacts with the deprotonated MA to generate MFAI and other related organic ammonium salts, which undergo subsequent reactions after deprotonation. The additive molecules and Michael addition reactions can also inhibit the I in the perovskite precursor solution. -Oxidation, thereby improving the stability of the precursor solution. In addition, aromatic amines or N-containing heterocyclic rings and α, β-unsaturated aldehydes and ketones are added to the precursor solution of organic halides as regulators of perovskite nucleation / crystallization. Thanks to the in-situ Michael addition reaction of aromatic amines or N-containing heterocyclic rings with α, β-unsaturated aldehydes and ketones, the release rate of organic halides is effectively delayed through the interaction between the reactants and their products and FAI, and the rapid reaction between organic halides and metal halides is inhibited. Finally, the functional groups of the reaction products remaining on the film surface / grain boundaries can effectively passivate uncoordinated lead ions or iodine defects, thereby obtaining high-quality perovskite homogeneous films.

[0007] Based on the core of the above method, in the first aspect, the method for improving the quality of perovskite film disclosed in the present invention comprises:

[0008] The organic halide precursor solution contains aromatic amine or N-containing heterocyclic ring and α,β-unsaturated aldehyde or ketone, and the aromatic amine or N-containing heterocyclic ring and the α,β-unsaturated aldehyde or ketone undergo in-situ Michael addition reaction.

[0009] In the present disclosure and possible embodiments, the aromatic amine includes aniline having different substituents at the ortho, meta or para positions; and / or,

[0010] The N-containing heterocyclic ring includes pyrrole and its derivatives, imidazole and its derivatives, indole and its derivatives, and purine and its derivatives; and / or,

[0011] The α,β-unsaturated aldehydes and ketones include acrolein, 3-butene-2-one and 1-pentene-3-one.

[0012] In the present disclosure and possible embodiments, the aniline containing different substituents at the ortho-position, meta-position or para-position includes p-toluidine, p-fluoroaniline and p-aminobenzoic acid.

[0013] In the present disclosure and possible embodiments, aromatic amines or N-containing heterocyclic rings and α,β-unsaturated aldehydes and ketones are added to an isopropanol solution of formamidine hydroiodide and methylammonium chloride to obtain the organic halide precursor solution.

[0014] In the present disclosure and possible embodiments, the concentration of the aromatic amine or N-containing heterocycle in the organic halide precursor solution is 0.02 to 0.5 mg / mL;

[0015] The molar ratio of the aromatic amine or N-containing heterocycle to the α,β-unsaturated aldehyde or ketone is 1:1.

[0016] In a second aspect, the perovskite film disclosed in the present invention comprises:

[0017] A metal halide layer, based on which an organic halide precursor solution is coated on the metal halide layer, and the perovskite film is generated by a reaction between the metal halide and the organic halide;

[0018] The organic halide precursor solution contains aromatic amine or N-containing heterocyclic ring and α,β-unsaturated aldehyde or ketone, and the aromatic amine or N-containing heterocyclic ring and the α,β-unsaturated aldehyde or ketone undergo in-situ Michael addition reaction.

[0019] In the present disclosure and possible embodiments, the molecular structure of the perovskite film is ABX3, wherein A is one or more of FA, MA, and Cs, B is one or more of Pb and Sn, and X is one or more of Cl, Br, and I.

[0020] In the present disclosure and possible embodiments, the metal halide is lead iodide, and the organic halide precursor solution contains formamidine hydroiodide, methylammonium chloride, isopropanol, aromatic amine, or N-containing heterocyclic and α,β-unsaturated aldehydes and ketones.

[0021] In a third aspect, the perovskite solar cell disclosed in the present disclosure comprises:

[0022] The perovskite light absorbing layer is composed of the perovskite thin film described in the second aspect.

[0023] In the present disclosure and possible embodiments, the perovskite light absorbing layer has a passivation layer on it, and the phenethylammonium iodide solution is coated on the surface of the perovskite light absorbing layer to obtain the passivation layer. The present invention has the following beneficial effects:

[0024] The method for improving the quality of perovskite film disclosed in the present invention introduces an additive composed of aromatic amine or N-heterocyclic ring and α, β-unsaturated aldehydes and ketones into a precursor solution of an organic halide to cause an in-situ Michael addition reaction. First, the α, β-unsaturated aldehydes and ketones can react with the deprotonated amine molecules in the precursor solution to block the subsequent reactions that occur in the perovskite precursor solution after the deprotonation of the organic ammonium salt. At the same time, the additive and the Michael addition reaction process can inhibit the perovskite precursor solution from being stored under ambient conditions. - Oxidation improves the environmental stability and 60°C stability of the precursor solution.

[0025] In addition, based on the in situ Michael addition reaction, the functional groups in the reactants and products can interact with FAI through hydrogen bonds (NH…F, NH…O). Due to the existence of intermolecular interactions, the release rate of FAI is slowed down, and the reaction rate of FAI and lead iodide is delayed, thereby promoting the transformation of PbI2 to the α-phase perovskite phase, and obtaining a perovskite film with a larger grain size and lower defect state density. The perovskite solar cell prepared based on this has a higher energy conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings herein are incorporated into the specification and constitute a part of the specification. These drawings illustrate embodiments consistent with the present disclosure and are used to illustrate the technical solutions of the present disclosure together with the specification.

[0027] Figure 1 It is a schematic diagram of the structure of the perovskite solar cell of Examples 1-4 of the present disclosure;

[0028] Figure 2 is a flow chart of a method for preparing a perovskite solar cell according to embodiments 1 to 4 of the present disclosure;

[0029] Figure 3 The possible reaction mechanism of in situ Michael addition reaction in isopropanol of organic halide precursor solution;

[0030] Figure 4 is the hydrogen nuclear magnetic resonance spectrum of the Michael addition reaction product in Example 1;

[0031] Figure 5 The H NMR spectra of the control group in Example 1 and the organic halide precursor solution after adding 1-(4-aminophenyl)-2,2,2-trifluoroethanone and 1-penten-3-one, heated at 60° C. for 16 h under N2 conditions;

[0032] Figure 6 This is a graph showing the color change of the organic halide precursor solution stored under ambient conditions in the control group in Example 1 and after adding 1-(4-aminophenyl)-2,2,2-trifluoroethanone and 1-penten-3-one;

[0033] Figure 7 The hydrogen nuclear magnetic resonance spectra of pure FAI, FAI, 1-(4-aminophenyl)-2,2,2-trifluoroethanone and 1-penten-3-one in Example 1;

[0034] Figure 8-1 and Figure 8-2 They are scanning electron microscope images of the control perovskite film in Example 1 and the perovskite film after adding 1-(4-aminophenyl)-2,2,2-trifluoroethanone and 1-penten-3-one;

[0035] Fig. 9 The X-ray photoelectron spectra of Pb 4f orbitals of the control group and experimental group films in Example 1;

[0036] Figure 10-1 and Figure 10-2 This is the space charge limited current test of the pure hole devices in the control group and the experimental group in Example 1;

[0037] Fig.11 The transient photocurrent test of the control group and the experimental group devices in Example 1;

[0038] Fig.12 This is a comparison chart of energy conversion efficiency between the control group in Example 1 and the experimental group after adding 1-(4-aminophenyl)-2,2,2-trifluoroethanone and 1-penten-3-one;

[0039] Fig.13 The normalized efficiency of the prepared devices when the organic halide precursor solutions of the control group and the experimental group in Example 1 are stored in the air for different time periods;

[0040] Fig.14 is the hydrogen nuclear magnetic resonance spectrum of the Michael addition reaction product in Example 2;

[0041] Fig.15 This is a scanning electron microscope image of the perovskite film after adding p-aminobenzoic acid and 1-penten-3-one in Example 2;

[0042] Fig.16 It is the normalized efficiency of the devices prepared by storing the organic halide precursor solutions of the control group and the experimental group in Example 2 in the air for different time periods. DETAILED DESCRIPTION

[0043] The present disclosure is described below based on embodiments, but it is worth noting that the present disclosure is not limited to these embodiments. In the detailed description of the present disclosure below, some specific details are described in detail. However, for the parts that are not described in detail, those skilled in the art can also fully understand the present disclosure.

[0044] Furthermore, unless the context clearly requires otherwise, throughout the specification and claims, the words "include," "comprises," and similar words should be interpreted in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to."

[0045] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0046] Attached Figure 3 The possible reaction mechanism of the in situ Michael addition reaction in isopropanol as an organic halide precursor solution is given by Figure 5 It can be seen that aromatic amines or N-containing heterocyclic rings and α, β-unsaturated aldehydes and ketones are introduced into the precursor solution of organic halides. The α, β-unsaturated aldehydes and ketones can react with the deprotonated amine molecules in the precursor solution, thereby blocking the subsequent reactions that occur in the perovskite precursor solution after the deprotonation of the organic ammonium salt. The solution components are modulated by the additive molecules to avoid side reactions in the solution, thereby effectively inhibiting the irreversible degradation process of the precursor solution. Figure 6 It can be seen that the introduction of aromatic amines or N-containing heterocyclic and α,β-unsaturated aldehydes and ketones into the precursor solution of organic halides can inhibit the I - Oxidation in the air and reduction of the oxidized iodine to I - , improving the stability of the perovskite precursor solution under ambient conditions and at 60°C.

[0047] In addition, the in situ Michael addition reaction of aromatic amines or N-containing heterocycles with α,β-unsaturated aldehydes and ketones effectively delays the release rate of organic halides and inhibits the rapid reaction between organic halides and metal halides through the interaction between the reactants and their products and FAI, thereby regulating the nucleation / crystallization of perovskite, obtaining high-quality perovskite films, and obtaining high-performance perovskite devices.

[0048] Therefore, the perovskite solar cell based on the Michael addition reaction disclosed in the present invention can regulate the components of the precursor solution and the crystallization by utilizing the reactants participating in the Michael addition and the in-situ Michael addition reaction, thereby realizing the preparation of efficient and stable perovskite solar cells.

[0049] The method for preparing α-FAPbI3 perovskite film in each embodiment of the present disclosure comprises the following steps:

[0050] 1. Prepare a lead iodide (PbI2) precursor solution, spin-coat or scrape-coat the lead iodide precursor solution onto the electron or hole transport layer of the transparent conductive substrate, and obtain a lead iodide film after annealing to form a lead iodide layer on the electron or hole transport layer.

[0051] In a specific embodiment, the method for preparing the lead iodide precursor solution is to dissolve the lead iodide in a mixed solution of DMF and DMSO (the volume ratio of DMF:DMSO is 9.5:0.5 or 9:1) under a N2 atmosphere to obtain a 1.3 mol / L or 1.5 mol / L PbI2 precursor solution.

[0052] In a specific embodiment, the PbI2 precursor solution is filtered, and then spin-coated or scraped onto the electron or hole transport layer at 1500 rpm / 30 s, and annealed at 70° C. for 1 min to form a PbI2 thin film.

[0053] 2. Prepare a FAI precursor solution with aromatic amine or N-containing heterocyclic ring and α, β-unsaturated aldehyde or ketone added, spin-coat or scrape-coat the FAI precursor solution onto the prepared lead iodide film, react between metal halide and organic halide, and react in situ Michael addition reaction between aromatic amine or N-containing heterocyclic ring and α, β-unsaturated aldehyde or ketone. After annealing, an α-FAPbI3 perovskite film is obtained, and a perovskite light absorbing layer is generated on the electron or hole transport layer.

[0054] In a specific embodiment, the molecular structure of the perovskite light-absorbing layer is ABX3, wherein A is one or more of FA, MA, and Cs, B is one or more of Pb and Sn, and X is one or more of Cl, Br, and I.

[0055] In a specific embodiment, the method for preparing the FAI precursor solution is to weigh 60-90 mg of formamidine hydroiodide (FAI) and 14-18 mg of methylammonium chloride (MACl), dissolve them in 1 mL of isopropanol (IPA), and continue to add aromatic amines or N-containing heterocyclic rings and α, β-unsaturated aldehydes and ketones to the precursor solution to obtain 0.35-0.52 mol / L FAI precursor solution.

[0056] In a specific embodiment, the concentration of the aromatic amine or the N-containing heterocycle in the FAI precursor solution is 0.02-0.5 mg / mL; and the molar ratio of the aromatic amine or the N-containing heterocycle to the α,β-unsaturated aldehyde or ketone is 1:1.

[0057] In a specific embodiment, the FAI precursor solution is filtered and then spin-coated on the lead iodide layer at 1500 rpm / 30 s or 1800 rpm / 30 s, and annealed at 150° C. for 15 min under ambient conditions (30-40% RH) to form a perovskite film.

[0058] In a specific embodiment, the aromatic amine is aniline containing different substituents at the ortho, meta or para position, such as p-toluidine, p-fluoroaniline, p-aminobenzoic acid and other aniline derivatives; the N-containing heterocyclic ring is pyrrole and its derivatives, imidazole and its derivatives, indole and its derivatives, purine and its derivatives and other N-containing heterocyclic ring derivatives; the α,β-unsaturated aldehydes and ketones are acrolein, 3-butene-2-one or 1-pentene-3-one.

[0059] The disclosed embodiment prepares α-FAPbI3 perovskite solar cells, such as Figure 1 As shown, the structure of the solar cell is, from top to bottom, a transparent conductive substrate, an electron transport layer, a perovskite light absorbing layer, a hole transport layer and a metal electrode; or a transparent conductive substrate, a hole transport layer, a perovskite light absorbing layer, an electron transport layer and a metal electrode; as Figure 2 As shown, the preparation method of the perovskite solar cell comprises the following steps:

[0060] 1. Take a transparent conductive substrate and prepare an electron or hole transport layer on the transparent conductive substrate;

[0061] In a specific embodiment, the transparent conductive substrate includes two parts: a transparent substrate and a conductive layer, wherein the transparent substrate is one of a glass substrate, a quartz substrate, a PET plastic substrate, a PEN plastic substrate, and a PI plastic substrate, and the conductive layer is one of indium tin oxide, fluorine-doped tin dioxide, or a grid silver film prepared thereon.

[0062] In a specific embodiment, the electron transport layer material is one or more of ZnO, TiO2, SnO2, PCBM, fullerene, and fullerene derivatives.

[0063] In a specific embodiment, the hole transport layer material is one or more of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly-3,4-ethylenedioxythiophene / polystyrene sulfonate, nickel oxide, copper oxide, 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene, cuprous thiocyanate, and molybdenum oxide.

[0064] 2. Prepare a metal halide precursor solution, spin-coat or scrape-coat the metal halide precursor solution onto the prepared electron or hole transport layer, and obtain a metal halide film after annealing, thereby forming a metal halide on the electron or hole transport layer.

[0065] In a specific embodiment, the metal halide is lead iodide (PbI2), and the metal halide film is prepared according to the method for preparing an α-FAPbI3 perovskite film in an embodiment of the present disclosure.

[0066] 3. Prepare an organic halide precursor solution, and add reactants that can undergo Michael addition reaction, such as aromatic amines or N-containing heterocycles and α, β-unsaturated aldehydes and ketones, to the organic precursor solution, spin-coat or scrape the organic halide precursor solution onto the prepared metal halide film, and generate a perovskite film through the reaction between the metal halide and the organic halide, and the perovskite film constitutes a perovskite light absorbing layer.

[0067] In a specific embodiment, the perovskite film is prepared according to the method for preparing an α-FAPbI3 perovskite film according to an embodiment of the present disclosure.

[0068] 4. Spin-coat or scrape the phenylethylammonium iodide solution on the surface of the perovskite light-absorbing layer to obtain a passivation layer.

[0069] In a specific embodiment, phenethylammonium iodide (PEAI) is weighed and dissolved in isopropyl alcohol (IPA) to obtain a 15-25 mmol / L PEAI precursor solution; the PEAI solution is filtered and then spin-coated on the surface of the perovskite light-absorbing layer at 5000 rpm / 30s to form a PEAI passivation layer.

[0070] 5. Prepare a hole or electron transport layer on the perovskite light absorption layer passivation layer and vacuum evaporate a metal electrode.

[0071] In a specific embodiment, the metal electrode is one or more of an Au electrode, an Ag electrode, an Al electrode, a Cu electrode, and a metal oxide electrode.

[0072] The following are specific embodiments of the present disclosure:

[0073] Example 1

[0074] 1. This embodiment prepares an α-FAPbI3 perovskite solar cell. During the preparation process, the perovskite crystallization is regulated based on the in-situ Michael addition reaction, and finally a high-performance perovskite solar cell can be obtained. The specific steps are as follows:

[0075] 1. Preparing an electron transport layer or a hole transport layer on the transparent conductive substrate:

[0076] The ITO conductive glass was ultrasonicated in deionized water, acetone, ethanol and isopropanol for 15 to 20 minutes in sequence, then dried under nitrogen conditions, and treated with UV / ozone for 25 minutes; 1.0 mL of 15% SnO2 solution was taken with a pipette, 6.0 mL of deionized water was added, and the concentration of the SnO2 solution was diluted to 2.14 wt% to form an electron transport layer solution; the electron transport layer solution was filtered, spin-coated on the ITO conductive glass at 4000 rpm / 30s, annealed at 150°C for 30 minutes to form an electron transport layer, treated with UV-ozone for 8 minutes, and then transferred to a glove box filled with N2;

[0077] 2. Prepare a lead iodide layer on the electron transport layer or the hole transport layer:

[0078] In a N2 glove box, 599.3 mg of lead iodide (PbI2) was weighed and dissolved in a mixed solution of DMF and DMSO (the volume ratio of DMF:DMSO was 9.5:0.5), and stirred at 60°C for 10 h to obtain a 1.3 mol / L PbI2 precursor solution; after filtering the PbI2 precursor solution, spin-coated it on the electron transport layer or the hole transport layer at 1500 rpm / 30 s, and annealed at 70°C for 1 min to form a PbI2 thin film to obtain a lead iodide layer.

[0079] 3. Coating the organic halide precursor solution on the lead iodide layer, generating a perovskite film through the reaction of lead iodide and the organic halide to form a perovskite light-absorbing layer, and preparing a high-quality perovskite film through an in-situ Michael addition reaction between 1-(4-aminophenyl)-2,2,2-trifluoroacetone and 1-penten-3-one:

[0080] 60 mg of formamidine hydroiodide (FAI) and 14 mg of methylammonium chloride (MACl) were weighed and dissolved in 1 mL of isopropanol (IPA), and 0.05 mg of 1-(4-aminophenyl)-2,2,2-trifluoroethanone and 1-penten-3-one in a corresponding molar ratio were added to the precursor solution to obtain a 0.35 mol / L FAI precursor solution; the FAI precursor solution was filtered and spin-coated on the lead iodide layer at 1500 rpm / 30 s, and annealed at 150° C. for 15 min under ambient conditions (30-40% RH) to form a perovskite film.

[0081] 4. Prepare a passivation layer on the perovskite light-absorbing layer:

[0082] 5 mg of phenylethylammonium iodide (PEAI) was weighed and dissolved in 1 mL of isopropyl alcohol (IPA) to obtain a 20 mmol / L PEAI precursor solution; the PEAI solution was filtered and then spin-coated on the perovskite light-absorbing layer at 5000 rpm / 30 s to form a PEAI passivation layer.

[0083] 5. After preparing the electron transport layer or the hole transport layer on the passivation layer, vacuum evaporation is performed on the metal electrode:

[0084] Weigh 520 mg of lithium bis(trifluoromethanesulfonyl imide) and dissolve it in 1 mL of anhydrous acetonitrile to obtain a lithium bis(trifluoromethanesulfonyl imide) solution; take 72.3 mg of Spiro-OMeTAD and dissolve it in 1 mL of chlorobenzene, then add 17.5 μL of lithium bis(trifluoromethanesulfonyl imide) solution and 28.8 μL of 4-tert-butylpyridine solution; filter the Spiro-OMeTAD solution and spin coat it on the passivation layer at 3000 rpm / 20 s to obtain a hole transport layer.

[0085] At vacuum degree <1×10 -5 Under the conditions of Tor, metal Ag was evaporated on the hole transport layer at a rate of 0.1 to 0.5 A / s to form a 100 nm Ag electrode to obtain the α-FAPbI3 perovskite solar cell of Example 1.

[0086] 2. Precursor solution, thin film, and solar cell testing:

[0087] In order to compare with the preparation method of this embodiment 1, a control example in which 1-(4-aminophenyl)-2,2,2-trifluoroethanone and 1-penten-3-one were not added to the organic halide precursor solution was prepared simultaneously with this embodiment 1. The control group mentioned in the following test is this control example.

[0088] 1. Figure 4The H NMR spectrum of the Michael addition reaction product in Example 1, with 1-(4-aminophenyl)-2,2,2-trifluoroethanone and 1-penten-3-one as reactants, the H NMR spectrum of the product TFPO is shown in the figure, proving the feasibility of the reaction in the precursor solution;

[0089] in: 1 H NMR (400MHz, DMSO) δ7.78(d,2H),7.33(t,J=5.3Hz,1H),6.70(d,J=7.4Hz,2H),3.3 9–3.33(m,2H),2.74(t,J=6.6Hz,2H),2.46(q,J=7.3Hz,2H),0.93(t,J=7.3Hz,3H).

[0090] 2. Figure 5 The hydrogen nuclear magnetic resonance spectrum of the control group in Example 1 and the organic halide precursor solution after adding 1-(4-aminophenyl)-2,2,2-trifluoroethanone and 1-penten-3-one, heated at 60°C for 16 hours under N2 conditions, and the nuclear magnetic resonance data show that α, β-unsaturated aldehydes and ketones can eliminate excess organic amines through chemical reactions, avoid irreversible reactions in the precursor solution, and improve the stability of the precursor solution.

[0091] 3. Figure 6 This is a color change diagram of the control group in Example 1 and the organic halide precursor solution stored under ambient conditions after adding 1-(4-aminophenyl)-2,2,2-trifluoroethanone and 1-penten-3-one. By comparing the colors in the diagram, it can be proved that the storage stability of the organic halide precursor solution under ambient conditions is better than that of the control group.

[0092] 4. Figure 7 The nuclear magnetic resonance hydrogen spectra of pure FAI, FAI, 1-(4-aminophenyl)-2,2,2-trifluoroethanone and 1-penten-3-one in Example 1 show that the proton hydrogen in FAI shifts to the low field and splits at the same time, indicating that the proton chemical environment in FAI has changed, and there is a hydrogen bond interaction between FAI and the additive molecules. The hydrogen bond interaction slows down the release rate of FAI and slows down the reaction between FAI and Pb 2+ The reaction rate is reduced, thereby obtaining high-quality and homogeneous perovskite films.

[0093] 5. Figure 8-1 and Figure 8-2The scanning electron microscope images are respectively of the perovskite film of the control group in Example 1 and the perovskite film after adding 1-(4-aminophenyl)-2,2,2-trifluoroethanone and 1-penten-3-one. Compared with the film of the control group, the modified film has a larger grain size, which can prove the feasibility of providing large-area perovskite films and large-area perovskite solar cells in the present invention.

[0094] 6. Fig. 9 is the X-ray photoelectron spectrum of Pb 4f orbital of the control group and experimental group films in Example 1, Pb 2+ Both peaks of α and β shift to lower binding energies, indicating an increase in the electron density around Pb. This strong interaction can passivate the uncoordinated Pb 2+ , suppressing metallic lead defects in perovskite films.

[0095] 7. Figure 10-1 and Figure 10-2 The space charge limited current test of the pure hole devices in the control group and the experimental group in Example 1 shows that the trap filling limit voltage of the control group is 0.38 V, and its defect density is 1.05×10 16 cm -3 Compared with the control group, the trap filling limit voltage of the experimental group is 0.22V, and its defect density is 6.06×10 15 cm -3 The addition of additives regulates the crystallization process of α-FAPbI3, making the film have a lower defect density.

[0096] 8. Fig.11 The transient photocurrent test of the control group and the experimental group devices in Example 1 shows that the experimental group has a higher carrier lifetime (2.03 μs) than the control group's 0.74 μs. The increase in carrier lifetime indicates that non-radiative recombination is suppressed.

[0097] 9. Fig.12 This is a comparison chart of the energy conversion efficiency of the control group and the experimental group after adding 1-(4-aminophenyl)-2,2,2-trifluoroethanone and 1-penten-3-one in Example 1. Compared with the control group, the experimental group has a higher energy conversion efficiency;

[0098] 10. Fig.13 The normalized efficiency of the devices prepared by storing the organic halide precursor solutions of the control group and the experimental group in the air for different time periods in Example 1, the TFPO-based device has a higher efficiency than the control group device, indicating that the stability of the perovskite precursor solution is improved.

[0099] Example 2

[0100] This embodiment prepares an α-FAPbI3 perovskite solar cell, and the specific steps are as follows:

[0101] The ITO conductive glass was ultrasonicated in deionized water, acetone, ethanol and isopropanol for 15 to 20 minutes in sequence, then dried under nitrogen conditions, and treated with UV / ozone for 25 minutes; 1.0 mL of 15% SnO2 solution was taken with a pipette, 6.0 mL of deionized water was added, and the concentration of the SnO2 solution was diluted to 2.14 wt% to form an electron transport layer solution; the electron transport layer solution was filtered, spin-coated on the ITO conductive glass at 4000 rpm / 30s, annealed at 150°C for 30 minutes to form an electron transport layer, treated with UV-ozone for 8 minutes, and then transferred to a glove box filled with N2;

[0102] In a N2 glove box, 599.3 mg of lead iodide (PbI2) was weighed and dissolved in a mixed solution of DMF and DMSO (the volume ratio of DMF:DMSO was 9.5:0.5), and stirred at 60°C for 10 h to obtain a 1.3 mol / L PbI2 precursor solution; the PbI2 precursor solution was filtered, spin-coated at 1500 rpm / 30 s, and annealed at 70°C for 1 min to form a PbI2 film;

[0103] Weigh 60 mg of formamidine hydroiodide (FAI) and 14 mg of methylammonium chloride (MACl), dissolve them in 1 mL of isopropanol (IPA), add 0.05 mg of p-aminobenzoic acid and 1-penten-3-one in a corresponding molar ratio to the precursor solution to obtain a 0.35 mol / L FAI precursor solution; filter the FAI precursor solution, spin coat at 1500 rpm / 30 s, and anneal at 150° C. for 15 min under ambient conditions (30-40% RH) to form a perovskite film;

[0104] Weigh 5 mg of phenylethylammonium iodide (PEAI) and dissolve it in 1 mL of isopropyl alcohol (IPA) to obtain a 20 mmol / L PEAI precursor solution; filter the PEAI solution and spin-coat at 5000 rpm / 30 s to form a PEAI passivation layer;

[0105] Weigh 520 mg of lithium bis(trifluoromethanesulfonyl imide) and dissolve it in 1 mL of anhydrous acetonitrile to prepare a lithium bis(trifluoromethanesulfonyl imide) solution; take 72.3 mg of Spiro-OMeTAD and dissolve it in 1 mL of chlorobenzene, then add 17.5 μL of lithium bis(trifluoromethanesulfonyl imide) solution and 28.8 μL of 4-tert-butylpyridine solution; filter the Spiro-OMeTAD solution and spin coat it at 3000 rpm / 20 s to prepare a hole transport layer;

[0106] At vacuum degree <1×10 -5Under the condition of Tor, metal Ag was evaporated on the hole transport layer at a rate of 0.1 to 0.5 A / s to form a 100 nm Ag electrode.

[0107] Fig.14 The H NMR spectrum of the Michael addition reaction product in Example 2, with p-aminobenzoic acid and 1-penten-3-one as reactants, the H NMR spectrum of the product OBA is shown in the figure, and the generation proves the universality of the reaction in the precursor solution;

[0108] in: 1 H NMR (400MHz, DMSO) δ11.99(s,1H),7.67(d,J=8.7Hz,2H),6.55(d,J=8.7Hz,2H),6.37(t,J=5.4Hz,1H),3 .28(dd,J=12.4,6.5Hz,2H),2.70(t,J=6.7Hz,2H),2.47(dd,J=14.7,7.4Hz,2H),0.92(t,J=7.3Hz,3H);

[0109] Fig.15 This is a scanning electron microscope image of the perovskite film after adding p-aminobenzoic acid and 1-penten-3-one in Example 2, indicating that the modified film has a larger grain size.

[0110] Fig.16 The normalized efficiency of the devices prepared by storing the organic halide precursor solutions of the control group and the experimental group in the air for different time periods in Example 2, the OBA-based device has a higher efficiency than the control group device, indicating that this method for improving the stability of the perovskite precursor solution is universal.

[0111] Example 3

[0112] This embodiment prepares an α-FAPbI3 perovskite solar cell, and the specific steps are as follows:

[0113] The ITO conductive glass was ultrasonically treated in deionized water, acetone, ethanol and isopropanol for 15 to 20 minutes in sequence, then dried under nitrogen conditions, and treated with UV / ozone for 25 minutes; 1.0 mL of 15% SnO2 solution was taken with a pipette, 6.0 mL of deionized water was added, and the concentration of the SnO2 solution was diluted to 2.14 wt% to form an electron transport layer solution; the electron transport layer solution was filtered, spin-coated on the ITO conductive glass at 4000 rpm / 30s, annealed at 150°C for 30 minutes to form an electron transport layer, treated with UV-ozone for 10 minutes, and then transferred to a glove box filled with N2;

[0114] In a N2 glove box, 599.3 mg of lead iodide (PbI2) was weighed and dissolved in a mixed solution of DMF and DMSO (the volume ratio of DMF:DMSO was 9.5:0.5), and stirred at 60°C for 10 h to obtain a 1.3 mol / L PbI2 precursor solution; the PbI2 precursor solution was filtered, spin-coated at 1500 rpm / 30 s, and annealed at 70°C for 1 min to form a PbI2 film;

[0115] Weigh 60 mg of formamidine hydroiodide (FAI) and 14 mg of methylammonium chloride (MACl), dissolve them in 1 mL of isopropyl alcohol (IPA), add 0.05 mg of imidazole and acrolein in a corresponding molar ratio to the precursor solution to obtain a 0.35 mol / L FAI precursor solution; filter the FAI precursor solution, spin coat at 1500 rpm / 30 s, and anneal at 150° C. for 15 min under ambient conditions (30-40% RH) to form a perovskite film;

[0116] Weigh 5 mg of phenylethylammonium iodide (PEAI) and dissolve it in 1 mL of isopropyl alcohol (IPA) to obtain a 20 mmol / L PEAI precursor solution; filter the PEAI solution and spin-coat at 5000 rpm / 30 s to form a PEAI passivation layer;

[0117] Weigh 520 mg of lithium bis(trifluoromethanesulfonyl imide) and dissolve it in 1 mL of anhydrous acetonitrile to prepare a lithium bis(trifluoromethanesulfonyl imide) solution; take 72.3 mg of Spiro-OMeTAD and dissolve it in 1 mL of chlorobenzene, then add 17.5 μL of lithium bis(trifluoromethanesulfonyl imide) solution and 28.8 μL of 4-tert-butylpyridine solution; filter the Spiro-OMeTAD solution and spin coat it at 3000 rpm / 20 s to prepare a hole transport layer;

[0118] At vacuum degree <1×10 -5 Under the condition of Tor, metal Ag was evaporated on the hole transport layer at a rate of 0.1 to 0.5 A / s to form a 100 nm Ag electrode.

[0119] Example 4

[0120] This embodiment prepares an α-FAPbI3 perovskite solar cell, and the specific steps are as follows:

[0121] The ITO conductive glass was ultrasonicated in deionized water, acetone, ethanol and isopropanol in sequence for 15 to 20 minutes, then dried under nitrogen conditions, and treated with UV / ozone for 30 minutes; 1.0 mL of 15% SnO2 solution was taken with a pipette, 6.0 mL of deionized water was added, and the concentration of the SnO2 solution was diluted to 2.14 wt% to form an electron transport layer solution; the electron transport layer solution was filtered, spin-coated on the ITO conductive glass at 4000 rpm / 30s, annealed at 150°C for 30 minutes to form an electron transport layer, treated with UV-ozone for 5 minutes, and then transferred to a glove box filled with N2;

[0122] In a N2 glove box, 599.3 mg of lead iodide (PbI2) was weighed and dissolved in a mixed solution of DMF and DMSO (the volume ratio of DMF:DMSO was 9.5:0.5), and stirred at 60°C for 10 h to obtain a 1.3 mol / L PbI2 precursor solution; the PbI2 precursor solution was filtered, spin-coated at 1500 rpm / 30 s, and annealed at 70°C for 1 min to form a PbI2 film;

[0123] Weigh 60 mg of formamidine hydroiodide (FAI) and 14 mg of methylammonium chloride (MACl), dissolve them in 1 mL of isopropyl alcohol (IPA), add 0.05 mg of purine and acrolein in a corresponding molar ratio to the precursor solution to obtain a 0.35 mol / L FAI precursor solution; filter the FAI precursor solution, spin coat at 1500 rpm / 30 s, and anneal at 150° C. for 15 min under ambient conditions (30-40% RH) to form a perovskite film;

[0124] Weigh 5 mg of phenylethylammonium iodide (PEAI) and dissolve it in 1 mL of isopropyl alcohol (IPA) to obtain a 20 mmol / L PEAI precursor solution; filter the PEAI solution and spin-coat at 5000 rpm / 30 s to form a PEAI passivation layer;

[0125] Weigh 520 mg of lithium bis(trifluoromethanesulfonyl imide) and dissolve it in 1 mL of anhydrous acetonitrile to prepare a lithium bis(trifluoromethanesulfonyl imide) solution; take 72.3 mg of Spiro-OMeTAD and dissolve it in 1 mL of chlorobenzene, then add 17.5 μL of lithium bis(trifluoromethanesulfonyl imide) solution and 28.8 μL of 4-tert-butylpyridine solution; filter the Spiro-OMeTAD solution and spin coat it at 3000 rpm / 20 s to prepare a hole transport layer;

[0126] At vacuum degree <1×10 -5 Under the condition of Tor, metal Ag was evaporated on the hole transport layer at a rate of 0.1 to 0.5 A / s to form a 100 nm Ag electrode.

[0127] Example 5

[0128] This embodiment 5 provides a method for preparing a large-area perovskite solar cell. The difference between this embodiment 5 and embodiment 1 is that this embodiment 5 adopts a scraping method to prepare the perovskite light-absorbing layer, thereby expanding the production and application area. Specifically, the following steps are included:

[0129] The ITO conductive glass was ultrasonicated in deionized water, acetone, ethanol and isopropanol for 15 to 20 minutes, then dried under nitrogen and treated with UV / ozone for 20 minutes; 25 mg of NiO x Dissolve it in 1 mL of deionized water to prepare a 25 mg / mL hole transport layer precursor solution; add the hole transport layer precursor solution to the scraper coating equipment container, adjust the gap between the scraper and ITO to 100-150 μm, and then spread NiO at a speed of 15-20 mm / s. x The precursor solution was coated on an ITO substrate and annealed at 100 °C for 10 min.

[0130] In a glove box under N2, 599.3 mg of lead iodide (PbI2) was weighed and dissolved in a mixed solution of DMF and DMSO (the volume ratio of DMF:DMSO was 9.5:0.5), and stirred at 60°C for 10 h to obtain a 1.3 mol / L PbI2 precursor solution; a PbI2 layer was prepared by scraping on the hole transport layer. A certain volume of the precursor solution was measured and placed in a container of the scraping equipment (volume 5×5 cm 2 The substrate is usually 70 to 80 μL, 10×10 cm 2 Generally, 140-160 μL is used, and the coating machine is started to drip the solution into the gap between the coating blade and the substrate (about 0.2-0.4 mm). The system controller is used to control the blade to move horizontally at a speed of 15 mm / s to push the solution forward to obtain a PbI2 layer.

[0131] Weigh 60 mg of formamidine hydroiodide (FAI) and 14 mg of methylammonium chloride (MACl), dissolve them in 1 mL of isopropanol (IPA), and add 0.05 mg of 1-(4-aminophenyl)-2,2,2-trifluoroacetone and 1-pentene-3-one in the corresponding molar ratio to the precursor solution to obtain a 0.35 mol / L FAI precursor solution, and apply the above organic halide precursor solution on the PbI2 layer. Finally, use a nitrogen air knife to blow the film to a dry state, and then place it on a hot plate at 100°C for annealing for 10 minutes to completely remove the solvent.

[0132] Weigh 20 mg of PC 61 BM and dissolved in 1 mL of anhydrous chlorobenzene to prepare 20 mg / mL PC61 BM electron transport layer solution; then weigh 0.5 mg of BCP and dissolve it in 1 mL of anhydrous ethanol to prepare a 0.5 mg / mL BCP hole blocking layer solution; use the spin coating method to deposit the two on the perovskite light absorbing layer in turn, and the spin coating parameters are rotation speed 2000 rpm, rotation time 30 s and rotation speed 5000 rpm, rotation time 30 s.

[0133] At vacuum degree <1×10 -5 Under the condition of Tor, metal Ag was evaporated on the hole transport layer at a rate of 0.1 to 0.4 A / s to form a 100 nm Ag electrode.

[0134] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for improving the quality of perovskite film, characterized in that: include: The organic halide precursor solution contains aromatic amine or N-containing heterocyclic ring and α,β-unsaturated aldehyde or ketone, and the aromatic amine or N-containing heterocyclic ring and the α,β-unsaturated aldehyde or ketone undergo in-situ Michael addition reaction.

2. The method for improving the quality of perovskite thin films according to claim 1, characterized in that: The aromatic amine includes aniline having different substituents at the ortho, meta or para positions; and / or, The N-containing heterocyclic ring includes pyrrole and its derivatives, imidazole and its derivatives, indole and its derivatives, and purine and its derivatives; and / or, The α,β-unsaturated aldehydes and ketones include acrolein, 3-butene-2-one and 1-pentene-3-one.

3. The method for improving the quality of perovskite thin films according to claim 2, characterized in that: The anilines containing different substituents at the ortho, meta or para positions include p-toluidine, p-fluoroaniline and p-aminobenzoic acid.

4. The method for improving the quality of a perovskite film according to any one of claims 1 to 3, characterized in that: Aromatic amine or N-containing heterocyclic ring and α,β-unsaturated aldehyde or ketone are added to an isopropanol solution of formamidine hydroiodide and methylammonium chloride to obtain the organic halide precursor solution.

5. The method for improving the quality of perovskite thin films according to claim 4, characterized in that: The concentration of the aromatic amine or N-containing heterocyclic ring in the organic halide precursor solution is 0.02 to 0.5 mg / mL; The molar ratio of the aromatic amine or N-containing heterocycle to the α,β-unsaturated aldehyde or ketone is 1:

1.

6. A perovskite film, characterized in that: The film comprises: A metal halide layer, based on which an organic halide precursor solution is coated on the metal halide layer, and the perovskite film is generated by a reaction between the metal halide and the organic halide; The organic halide precursor solution contains aromatic amine or N-containing heterocyclic ring and α,β-unsaturated aldehyde or ketone, and the aromatic amine or N-containing heterocyclic ring and the α,β-unsaturated aldehyde or ketone undergo in-situ Michael addition reaction.

7. The perovskite film according to claim 6, characterized in that: The molecular structure of the perovskite film is ABX3, wherein A is one or more of FA, MA, and Cs, B is one or more of Pb and Sn, and X is one or more of Cl, Br, and I.

8. The perovskite film according to claim 7, characterized in that: The metal halide is lead iodide, and the organic halide precursor solution contains formamidine hydroiodide, methylammonium chloride, isopropanol, aromatic amine or N-containing heterocyclic and α,β-unsaturated aldehydes and ketones.

9. A perovskite solar cell, characterized in that: include: A perovskite light absorbing layer, wherein the perovskite light absorbing layer is composed of the perovskite film according to any one of claims 6 to 8.

10. The perovskite solar cell according to claim 9, characterized in that: The perovskite light-absorbing layer has a passivation layer on it, and the phenethylammonium iodide solution is coated on the surface of the perovskite light-absorbing layer to obtain the passivation layer.

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