Perovskite thin film containing bifunctional additive, light emitting diode, method of preparation

Abstract

The disclosure provides a perovskite film containing a bifunctional additive, a light-emitting diode and a preparation method thereof, wherein the bifunctional additive has a structure as shown in formula (1): wherein A1 is selected from C1-C5 alkyl; X is selected from at least one lone pair electron group containing N, O, F, Cl, Br and I, the lone pair electron group forms an intermolecular hydrogen bond self-assembly structure with the amino group in formula (1) as a physical spacing layer, inhibits the loss of non-radiative energy of the perovskite film caused by the generation of low-energy state exciton complexes at the interface of the charge transport layer, and passivates the unsaturated lead dangling bond caused by halide vacancies, thereby reducing defects in the perovskite film. By using the hydrogen bond or intermolecular force formed between the amino group in the additive and the amino group in formamidinium hydroiodide in the perovskite system, the grain growth during the perovskite film formation process is slowed down, thereby inducing the FAPbI3 perovskite film to have higher crystallinity, and improving the quality and light-emitting efficiency of the film.

Description

Technical Field

[0001] This disclosure belongs to the field of optoelectronic technology, and particularly relates to a perovskite thin film containing bifunctional additives, a perovskite light-emitting diode based on FAPbI3 and its preparation method, and more specifically to a near-infrared perovskite light-emitting diode based on a perovskite thin film containing bifunctional additives and its preparation method. Background Technology

[0002] Perovskite materials possess unique optoelectronic properties, including high absorption coefficients, easily tunable optical band gaps, high electron-hole mobility, long carrier diffusion lengths, high defect tolerance, high color purity, and solvent-processable characteristics, making them highly valuable and promising for applications in light-emitting diodes (LEDs). Over the past decade, perovskite LEDs have achieved external quantum efficiency (EQE) exceeding 23%. Currently, most perovskite LEDs achieve high EQE at low current densities (<0.1 mA cm⁻¹). -2 ) and low brightness (<1W sr) -1 m -2 The value was obtained at high brightness (>100Wsr). -1 m -2 The external quantum efficiency of the device is greatly reduced and it degrades rapidly under these conditions, which limits the commercial application of perovskite light-emitting diodes.

[0003] Three-dimensional (3D) perovskites have been proven to be candidate materials for high-brightness light-emitting diodes (LEDs) due to their unique optoelectronic properties, such as high carrier mobility, relatively balanced bipolar charge transport, and low Auger recombination. However, poor film morphology and high defect-induced nonradiative energy loss severely hinder further performance improvements. Simultaneously, severe nonradiative energy loss at the charge transport layer interface also causes a significant decrease in the EQE and poor stability of perovskite LEDs at high brightness.

[0004] Therefore, it is essential to develop a multifunctional additive and apply it to perovskites to solve the aforementioned technical problems, while maintaining high EQE and device stability at high brightness, thus addressing the key challenges currently faced by commercial perovskite light-emitting diodes. Summary of the Invention

[0005] To address the aforementioned technical problems, this disclosure provides a perovskite thin film containing a bifunctional additive, a light-emitting diode, and a preparation method, aiming to at least partially solve the above-mentioned technical problems.

[0006] To solve the above-mentioned technical problems, the technical solution provided in this disclosure is as follows:

[0007] As a first aspect of this disclosure, a perovskite thin film containing a bifunctional additive is provided, the bifunctional additive having a structure as shown in formula (1):

[0008]

[0009] Wherein, A1 is selected from C1-C5 alkyl groups;

[0010] X is selected from a lone pair electron group containing at least one of N, O, F, Cl, Br, and I, and the lone pair electron group forms an intermolecular hydrogen bond with the amino group in formula (1).

[0011] In one embodiment, the alkyl group in the bifunctional additive includes -CH2-CH2-.

[0012] In one embodiment, X in the bifunctional additive includes any one of the following lone pair electron groups:

[0013]

[0014] In one embodiment, X in the bifunctional additive includes any one of the following lone pair electron groups:

[0015]

[0016] In one embodiment, the bifunctional additive includes any one of the following:

[0017]

[0018]

[0019]

[0020]

[0021] As a second aspect of this disclosure, a perovskite light-emitting diode based on FAPbI3 is provided, the perovskite light-emitting diode comprising, from bottom to top:

[0022] A glass substrate with an ITO conductive thin film, an electron transport layer, a modification layer, a FAPbI3-based perovskite light-emitting layer, a hole transport layer, a hole injection layer, and electrodes;

[0023] The perovskite luminescent layer based on FAPbI3 includes a three-dimensional cubic phase FAPbI3 perovskite doped with the aforementioned bifunctional additives.

[0024] In one embodiment, the FAPbI3-based perovskite light-emitting layer includes:

[0025] Formamidin hydroiodide, lead iodide, and additives containing bifunctional groups;

[0026] The molar ratio of formamidin hydroiodide, lead iodide, and additives is 2.7∶1∶x, where x=0.1-1.

[0027] In one embodiment, wherein:

[0028] The electron transport layer includes: ZnO;

[0029] The modification layer includes: ethoxylated polyethyleneimine;

[0030] The hole transport layer includes: poly[bis(4-phenyl)(4-butylphenyl)amine] or poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)];

[0031] The hole injection layer includes molybdenum oxide;

[0032] The electrodes can be any one of Au, Ag, Cu, and Al.

[0033] In one embodiment, wherein:

[0034] The thickness of the electron transport layer is 30-50 nm;

[0035] The thickness of the modification layer is 0.1-2 nm;

[0036] The thickness of the perovskite luminescent layer based on FAPbI3 is 10-50 nm;

[0037] The thickness of the hole transport layer is 20-60 nm;

[0038] The thickness of the hole injection layer is 5-10 nm;

[0039] The thickness of the electrode is 50-200 nm.

[0040] As a third aspect of this disclosure, a method for fabricating the above-mentioned perovskite light-emitting diode is provided, comprising:

[0041] Step 1: Clean the glass substrate with the ITO conductive film and perform plasma treatment.

[0042] Step 2: On a glass substrate with an ITO conductive thin film after plasma treatment, an electron transport layer, a modification layer, and a perovskite light-emitting layer based on FAPbI3 are sequentially prepared by spin coating.

[0043] Step 3: On the FAPbI3-based perovskite light-emitting layer, a hole transport layer is prepared by spin coating, and a hole injection layer and an electrode are deposited by vacuum evaporation.

[0044] The FAPbI3-based perovskite luminescent layer includes:

[0045] Formamidin hydroiodide, lead iodide, and the above-mentioned bifunctional additives;

[0046] The molar ratio of formamidinium hydroiodate, lead iodide, and bifunctional additives is 2.7:1:x, where x = 0.1-1.

[0047] Based on the above technical solution, the perovskite thin film containing bifunctional additives, the light-emitting diode, and the preparation method provided in this disclosure have at least one of the following beneficial effects:

[0048] (1) According to embodiments of this disclosure, lone-pair electron groups are introduced into aliphatic amine compounds to form bifunctional additives suitable for perovskite films. The intermolecular hydrogen bond self-assembly structure formed by the lone-pair electron groups in the additives and the amino groups in the aliphatic amine compounds serves as a physical spacer layer, which can suppress the loss of nonradiative energy of the perovskite film caused by the generation of low-energy excitosome complexes in the charge transport layer. At the same time, the lone-pair electron groups in the additives, as Lewis bases, can also passivate the unsaturated lead dangling bonds in the perovskite, reducing defects in the perovskite film and reducing or eliminating nonradiative dark areas in the perovskite film. In addition, the amino groups in the aliphatic amine compounds can form hydrogen bonds or intermolecular forces with the amino groups of formamidinium hydroiodate in the perovskite system, thereby weakening the interaction between formamidinium hydroiodate and perovskite. This can effectively slow down the growth rate of perovskite grains during the perovskite film formation process, thereby inducing higher crystallinity in the FAPbI3 perovskite film and improving the quality of the perovskite film. In the embodiments of this disclosure, by utilizing the multifunctional effects of the above-mentioned additives, the grains in the perovskite film are uniformly distributed, the film surface is flat and uniform, thereby improving the quality and luminous efficiency of the perovskite film and inducing uniform light emission.

[0049] (2) According to embodiments of this disclosure, the perovskite thin film containing bifunctional additives provided in this disclosure is applied to a FAPbI3-based perovskite light-emitting layer and fabricated into a light-emitting diode. The intermolecular hydrogen bonds formed between the lone pair electron groups in the additives and the amino groups in the aliphatic amine compounds can act as a physical barrier layer, eliminating direct contact between the electron layer and hole transport layer in the perovskite light-emitting diode and suppressing non-radiative energy loss of the perovskite at the charge transport layer interface. This allows the perovskite light-emitting diode to operate at higher current densities (10-1000 mA / cm²). -2 Maintaining a high external quantum efficiency (above 10%) also helps improve the device stability of light-emitting diodes. Attached Figure Description

[0050] Figure 1This is a high-resolution scanning transmission electron microscope image of a perovskite light-emitting diode based on FAPbI3 in an embodiment of this disclosure.

[0051] Figure 2 The graph shows the external quantum efficiency-current density curve of the perovskite light-emitting diode prepared in Example 1 of this disclosure under the conditions of perovskite concentration of 7 wt% and additive concentration of 0.5 molar ratio.

[0052] Figure 3 The electroluminescence spectrum of the perovskite light-emitting diode prepared in Example 1 of this disclosure is shown below, with a perovskite concentration of 7 wt% and an additive concentration of 0.5 molar ratio.

[0053] Figure 4 The additive-free perovskite light-emitting diode in Comparative Example 1 of this disclosure has an initial brightness of 100 W sr. -1 m -2 The following is a measurement chart of operational stability.

[0054] Figure 5 This is a measurement graph showing the operational stability of a perovskite light-emitting diode prepared in Example 1 of this disclosure under the conditions of a perovskite concentration of 7 wt% and an additive concentration of 0.5 molar ratio (where the current density is 50 mA cm⁻¹). -2 The initial brightness was 55 Wsr. -1 m -2 The current density is 100 mA cm⁻¹ -2 The initial brightness was 107W sr -1 m -2 The current density is 300 mA cm⁻¹ -2 The initial brightness was 253W sr -1 m -2 );

[0055] Figure 6 The figures show the peak external quantum efficiency and peak luminance of various NIR light-emitting diodes in the embodiments of this disclosure and in previous reports. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0057] Perovskite light-emitting diodes suffer from reduced external quantum efficiency and rapid degradation at higher current densities and brightness levels, limiting their practical applications. In view of this, this disclosure provides a bifunctional additive suitable for FAPbI3 perovskite thin films. This is achieved by introducing lone pair electron groups into aliphatic amine compounds, resulting in a multifunctional additive containing bifunctional groups (-NH2, lone pair electron groups). The amino groups in this additive can form hydrogen bonds or intermolecular forces with the amino groups of formamidinium hydroiodate in the perovskite film through strong interactions. This effectively slows down the growth rate of perovskite grains and reduces defects in the perovskite crystals during film formation, thus improving the quality of the film. Furthermore, the intermolecular hydrogen bonds formed between the lone pair electron functional groups introduced in the additive and the amino groups effectively eliminate direct contact between the electron and hole transport layers in the light-emitting diode (LED), thereby suppressing the loss of non-radiative energy of the perovskite at the charge transport layer interface. Simultaneously, the lone pair electron groups in the additive can passivate unsaturated lead dangling bonds caused by halide vacancies, reducing defects in the perovskite film. This results in a higher film quality for the perovskite film, which in turn helps the LED achieve higher luminous efficiency at higher current densities.

[0058] As a first aspect of this disclosure, a perovskite thin film containing a bifunctional additive is provided, wherein the bifunctional additive has a structure as shown in formula (1):

[0059]

[0060] Wherein, A1 is selected from C1-C5 alkyl groups;

[0061] X is selected from a lone pair electron group containing at least one of N, O, F, Cl, Br, and I, and the lone pair electron group forms an intermolecular hydrogen bond with the amino group in formula (1).

[0062] According to embodiments of this disclosure, A1 is selected from C1-C5 alkyl groups, wherein A1 is preferably a straight-chain alkyl group, and its synthesis method is relatively simple. The alkyl group includes -CH2-CH2-, and this alkyl group can be linked to another structural segment, such as -NH2.

[0063] According to embodiments of this disclosure, X in the bifunctional additive includes any one of the following lone pair electron groups:

[0064]

[0065] According to embodiments of this disclosure, the X group in the bifunctional additive is more preferably any one of the following lone pair electron groups:

[0066]

[0067] According to embodiments of this disclosure, the bifunctional additive having the structure shown in formula (1) includes at least any one of the following:

[0068]

[0069]

[0070]

[0071]

[0072] In the embodiments of this disclosure, the additive containing bifunctional groups is preferably an aliphatic amine compound in which the amino group and the lone pair electron group are in the para position. The main reason is that when the amino group and the lone pair electron group are in the ortho or meta position, in addition to intermolecular hydrogen bonds, there are also intramolecular hydrogen bonds between the amino group and the lone pair electrons. Intramolecular hydrogen bonds cannot separate the electron layer and the hole transport layer, resulting in non-radiative energy loss in some areas of the perovskite film, thus having a relatively small impact on the luminescence efficiency of the perovskite film.

[0073] According to embodiments of this disclosure, the specific synthesis method of the bifunctional additive in the above embodiments is as follows:

[0074] A 30 mL solution of 0.06 mol anhydrous aluminum trichloride in tetrahydrofuran (THF) was rapidly added to a 25 mL solution of 0.06 mol lithium aluminum hydride in THF under a nitrogen atmosphere, and the mixture was stirred at 0 °C for 10 minutes. This solution was then added to a 15 mL solution of 20 mmol phenylacetonitrile precursor of the target additive molecule to be synthesized in THF, and the mixture was stirred under a nitrogen atmosphere for 1 hour. The mixture was then carefully quenched with sodium sulfate decahydrate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was purified by silica gel column chromatography after filtration and evaporation, revealing that the target additive molecule to be synthesized contained an X group.

[0075] As a second aspect of this disclosure, a perovskite light-emitting diode based on FAPbI3 is provided. The perovskite light-emitting diode comprises, from bottom to top: a glass substrate having an ITO conductive film, an electron transport layer, a modification layer, a perovskite light-emitting layer based on FAPbI3, a hole transport layer, a hole injection layer, and an electrode; wherein, the perovskite light-emitting layer based on FAPbI3 includes a three-dimensional cubic phase FAPbI3 perovskite doped with bifunctional additives as described in the above embodiments. The three-dimensional cubic phase FAPbI3 perovskite has higher luminous efficiency and can emit near-infrared light.

[0076] According to embodiments of this disclosure, the perovskite emitting layer is a three-dimensional cubic FAPbI3 perovskite emitting layer, wherein the perovskite emitting layer is prepared by spin coating of formamidinium hydroiodate, lead iodide, and the aforementioned bifunctional additives, wherein the molar ratio of formamidinium hydroiodate, lead iodide, and additives is 2.7:1:x, where x = 0.1-1. Within this molar ratio range, the perovskite emitting layer exhibits good conductivity and high luminous efficiency. If the amount of additive is further increased beyond this molar ratio range, the conductivity of the perovskite film may decrease, affecting the optical performance and practical application of the perovskite light-emitting diode. The performance of the perovskite light-emitting diode device depends on the molar fraction of the dopant molecules relative to lead iodide, and optimal device performance is exhibited when x = 0.5.

[0077] According to embodiments of this disclosure, the thickness of the ITO (indium tin oxide) conductive film on the glass substrate is 100-200 nm, preferably 150 nm.

[0078] According to embodiments of this disclosure, the electron transport layer in a perovskite light-emitting diode includes ZnO with a thickness of 30-50 nm, wherein the thickness of the electron transport layer is preferably 35 nm.

[0079] According to embodiments of this disclosure, the modification layer in the perovskite light-emitting diode includes ethoxylated polyethyleneimine (PEIE) with a thickness of 0.1-2 nm, wherein the thickness of the modification layer is preferably 0.5 nm.

[0080] According to embodiments of this disclosure, the hole transport layer in the perovskite light-emitting diode comprises: poly[bis(4-phenyl)(4-butylphenyl)amine] (poly-TPD) or poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)] (TFB), with a thickness of 20-60 nm, wherein the hole transport layer thickness is preferably 40 nm.

[0081] According to embodiments of this disclosure, the thickness of the FAPbI3-based perovskite luminescent layer is 10-50 nm, preferably 30 nm.

[0082] According to embodiments of this disclosure, the hole injection layer in the perovskite light-emitting diode includes molybdenum oxide (MoOx) with a thickness of 5-10 nm, wherein the hole injection layer thickness is preferably 7 nm.

[0083] According to embodiments of this disclosure, the electrodes in a perovskite light-emitting diode include any one of Au, Ag, Cu, and Al, and their thickness is 50-200 nm, wherein the electrode thickness is preferably 60 nm.

[0084] In the embodiments of this disclosure, a bifunctional additive is doped into a three-dimensional cubic FAPbI3-based perovskite, which serves as the FAPbI3-based perovskite luminescent layer. The lone pair electron functional groups (containing N, O, and halogen groups) of the additive in the perovskite luminescent layer act as Lewis bases, which can passivate the unsaturated lead dangling bonds caused by halides in the perovskite, eliminating or reducing defects. At the same time, the intermolecular hydrogen bonds formed between the lone pair electron functional groups in the additive and amino groups can be used to achieve multilayer stacking within the perovskite molecule, thus enhancing the perovskite's luminescent properties. In perovskite LEDs, a physical spacer layer (hydrogen bond) is formed between the charge transport layer and the hole transport layer, which helps to eliminate the loss of non-radiative energy of the perovskite at the interface. Furthermore, the strong interaction (i.e., hydrogen bond or intermolecular force) between the amino groups in the additives and the amino groups of formamidinium hydroiodate (FAI) in the FAPbI3-based perovskite light-emitting layer effectively slows down the growth of grains during perovskite film formation, thereby inducing higher crystallinity. This results in perovskite LEDs based on FAPbI3 having higher luminous efficiency.

[0085] According to embodiments of this disclosure, a method for fabricating a FAPbI3-based perovskite light-emitting diode is also provided, comprising:

[0086] Step 1: Clean the glass substrate with the ITO conductive film and perform plasma treatment.

[0087] Step 2: On a glass substrate with an ITO conductive thin film after plasma treatment, an electron transport layer, a modification layer, and a perovskite light-emitting layer based on FAPbI3 are sequentially prepared by spin coating.

[0088] Step 3: On the FAPbI3-based perovskite light-emitting layer, a hole transport layer is prepared by spin coating, and a hole injection layer and an electrode are deposited by vacuum evaporation.

[0089] Among them, FAPbI3-based perovskites include:

[0090] Formamidin hydroiodide, lead iodide, and the bifunctional additives in the above examples;

[0091] The molar ratio of formamidinium hydroiodate, lead iodide, and bifunctional additives is 2.7:1:x, where x = 0.1-1.

[0092] Specifically, in step one, the glass substrate with the ITO conductive film is placed in detergent, deionized water, acetone and isopropanol in sequence, ultrasonically cleaned for 5 minutes each, then dried and treated with oxygen plasma to further remove organic matter on the ITO conductive film and form a certain roughness on its surface for subsequent spin coating deposition.

[0093] Specifically, in step two, the steps for sequentially preparing the electron transport layer ZnO and the modification layer PEIE using spin coating are as follows:

[0094] ZnO nanoparticles were spin-coated onto an ITO substrate at 3000 rpm and then annealed at 150 °C for 10 minutes. Subsequently, a 0.45 wt% PEIE solution in 2-methoxyethanol was spin-coated onto the ZnO electron transport layer at 5000 rpm and annealed at 100 °C for 15 minutes.

[0095] Specifically, the steps for preparing a perovskite light-emitting layer doped with bifunctional multifunctional additives using spin coating are as follows:

[0096] First, FAI, lead iodide, and dopant molecules were dissolved in N,N-dimethylformamide (DMF) at a molar ratio of 2.7:1:x (x = 0.1-1) to prepare a perovskite luminescent layer DMF dispersion with a dopant concentration of 5 wt%-15 wt%. Then, perovskite film deposition was performed in a nitrogen-filled glove box. The perovskite luminescent layer was spin-coated onto a ZnO / PEIE substrate at 3000 rpm for 60 seconds, followed by annealing at 100°C for 10 minutes. Preferably, the perovskite luminescent layer DMF dispersion with dopant was 7 wt%.

[0097] Specifically, in step three, a hole transport layer (poly-TPD) is prepared on the FAPbI3-based perovskite light-emitting layer using a spin-coating method, and a hole injection layer (MoOx) and an electrode are deposited sequentially using a vacuum evaporation method.

[0098] On top of the FAPbI3-based perovskite luminescent layer, a poly-TPD was spin-coated at 3000 rpm for 40 seconds. Finally, a 5×10⁻⁶ layer was applied. -6 Under a pressure of mbar, 7nm MoOx and 60nm Au were sequentially deposited as top electrodes by vacuum evaporation to obtain a perovskite light-emitting diode based on FAPbI3.

[0099] The FAPbI3-based perovskite light-emitting diode (LED) fabricated using the above method comprises, from bottom to top, a glass substrate with an ITO (indium tin oxide) conductive film, a ZnO electron transport layer and a perovskite light-emitting layer doped with a bifunctional multifunctional additive, a poly-TPD hole transport layer, a MoOx hole injection layer, and an Au electrode. The ITO conductive film has a thickness of 150 nm, the electron transport layer has a thickness of 35 nm, the modification layer has a thickness of ~0.5 nm, the perovskite light-emitting layer has a thickness of 30 nm, the hole transport layer has a thickness of 40 nm, the hole injection layer has a thickness of 7 nm, and the electrode has a thickness of 60 nm. A high-resolution scanning transmission electron microscope (HAADF-STEM) image of the perovskite LED fabricated using the method provided in this disclosure is shown below. Figure 1 As shown.

[0100] The aliphatic amine compounds represented by the above general formula (1), perovskite light-emitting diodes containing the same, and preparation methods are specifically described below with reference to specific embodiments and accompanying drawings. However, the following embodiments are merely illustrative of this disclosure, and the scope of this disclosure is not limited thereto.

[0101] Example 1: Synthesis of Compound 1-1 additive and preparation of corresponding perovskite light-emitting diodes

[0102] The synthesis method of compound 1-1 additive is as follows:

[0103]

[0104] A 30 mL solution of 0.06 mol anhydrous aluminum trichloride in THF was rapidly added to a 25 mL solution of 0.06 mol lithium aluminum hydride in THF under a nitrogen atmosphere, and stirred at 0 °C for 10 minutes. This was then added to a 15 mL solution of 20 mmol Al in THF, and stirred for 1 hour under a nitrogen atmosphere before being carefully quenched with sodium sulfate decahydrate. The resulting product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: hexane / ethyl acetate = 7:3, v / v) and recrystallized from chloroform / methanol to give a 1-1 white powder (1.52 g, yield: 38%, purity: 99.5%). 1H NMR (400MHz, DMF-d7)): δ8.08 (d, J=8.0Hz, 2H), 7.73 (d, J=3138.0Hz, 2H), 3.42 (s, 3H), 3.10 (m, 2H), 2.93 (m, 2H).

[0105] The fabrication process of the perovskite light-emitting diode doped with compound 1-1 is as follows:

[0106] A glass substrate with an ITO conductive film was sequentially immersed in detergent, deionized water, acetone, and isopropanol, and ultrasonically cleaned for 5 minutes each, then dried and treated with oxygen plasma. ZnO nanoparticles were spin-coated onto the ITO substrate at 3000 rpm and then annealed at 150 °C for 10 minutes. Subsequently, a 0.45 wt% PEIE solution dissolved in 2-methoxyethanol was spin-coated onto the ZnO electron transport layer at 5000 rpm and annealed at 100 °C for 15 minutes. FAI, lead iodide, and 1-1 additive molecules were dissolved in N,N-dimethylformamide (DMF) at a molar ratio of 2.7:1:x (x = 0.1-1) to prepare a perovskite luminescent layer DMF dispersion with a concentration of 5 wt%-15 wt% of the doped additive. Perovskite film deposition was then performed in a nitrogen-filled glove box. The perovskite luminescent layer was spin-coated onto a ZnO / PEIE substrate at 3000 rpm for 60 seconds, followed by annealing at 100°C for 10 minutes. On top of the perovskite luminescent layer, a poly-TPD was spin-coated at 3000 rpm for 40 seconds. Finally, a 5×10⁻⁶ layer was applied. -6 Under mbar pressure, 7nm MoO was deposited by vacuum evaporation. x The perovskite light-emitting diode device was fabricated by sequentially depositing 60nm Au as the top electrode.

[0107] The perovskite light-emitting diodes prepared using the method in Example 1 were subjected to EQE-current density characteristic curves and electroluminescence (EL) spectroscopy tests. Finally, with a perovskite dispersion concentration of 7 wt% and an additive-to-lead iodide molar ratio of 0.5, an 800 nm near-infrared perovskite light-emitting diode device with a maximum EQE of 23.8% was obtained, achieving a maximum EQE of up to 1000 mA cm⁻¹. -2 It can still maintain more than 10% EQE at current density. Figure 2 Compared to undoped perovskite light-emitting diodes (LEDs), this represents a certain improvement. Perovskite devices fabricated under other perovskite concentration and additive concentration conditions exhibit a combination of high EQE and high emissivity in the NIR range, surpassing previously reported perovskite (PeLED), organic (OLED), and quantum dot (QDLED) LEDs. (See appendix) Figure 6 Furthermore, the perovskite light-emitting diode in Example 1 has an initial brightness of 5 W sr. -1 m -2 Under irradiation, the device has a lifespan of up to 5*10. 4 It can achieve speeds comparable to currently commercialized organic and quantum dot light-emitting diodes.

[0108] Example 2: Synthesis of additives 1-3 and preparation of corresponding perovskite light-emitting diodes

[0109] The synthesis methods for additives 1-3 are as follows:

[0110] A3 (1 mmol), ethylene glycol (20 mmol), and p-toluenesulfonic acid (TsOH, 0.05 mmol) were mixed.

[0111]

[0112] Dissolve in toluene (15 ml) and reflux at 130 °C for 3 hours. After the reaction is complete, extract with ethyl acetate and dry the organic layer with anhydrous sodium sulfate. The crude product was filtered and evaporated, purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 8:2, v / v), and recrystallized from chloroform / methanol to give A3-1 (0.2 g, yield: 98.4%, purity: 99.5%).

[0113] A 30 mL solution of 0.06 mol anhydrous aluminum trichloride in THF was rapidly added to a 25 mL solution of 0.06 mol lithium aluminum hydride in THF under a nitrogen atmosphere, and stirred at 0 °C for 10 min. This solution was then added to a 15 mL solution of 20 mmol A3-1 in THF, and stirred for 1 hour under a nitrogen atmosphere before being carefully quenched with sodium sulfate decahydrate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 7:3, v / v) and recrystallized from chloroform / methanol to give A3-2 (1.66 g, yield: 40%, purity: 99.5%).

[0114] Concentrated hydrochloric acid (4 ml) was added to a 1 mmol THF solution (15 ml) of A3-2, and the mixture was refluxed at 60 °C for 4 hours. After the reaction was complete, the acidic reaction solution was alkalized to pH 10 with sodium carbonate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 7:3, v / v) and recrystallized from chloroform / methanol to give 1-3 white powder (0.11 g, yield: 66%, purity: 99.5%). Elemental analysis calculated C 10 H 13 NO (%): C, 73.59; H, 8.03; N, 8.58; O, 9.80 Measured values: C, 73.50; H, 8.07; N, 8.50; O, 9.88.

[0115] The fabrication process of perovskite light-emitting diodes doped with compounds 1-3 is as follows:

[0116] A glass substrate with an ITO conductive film was sequentially immersed in detergent, deionized water, acetone, and isopropanol, and ultrasonically cleaned for 5 minutes each, then dried and treated with oxygen plasma. ZnO nanoparticles were spin-coated onto the ITO substrate at 3000 rpm and then annealed at 150°C for 10 minutes. Subsequently, a 0.45 wt% PEIE solution dissolved in 2-methoxyethanol was spin-coated onto the ZnO electron transport layer at 5000 rpm and annealed at 100°C for 15 minutes. FAI, lead iodide, and 1-3 additive molecules were dissolved in N,N-dimethylformamide (DMF) at a molar ratio of 2.7:1:x (x = 0.1-1) to prepare a perovskite luminescent layer DMF dispersion with a concentration of 5 wt%-15 wt% of doped additives. Perovskite film deposition was then performed in a nitrogen-filled glove box. The perovskite luminescent layer was spin-coated onto a ZnO / PEIE substrate at 3000 rpm for 60 seconds, followed by annealing at 100°C for 10 minutes. On top of the perovskite luminescent layer, a poly-TPD was spin-coated at 3000 rpm for 40 seconds. Finally, a 5×10⁻⁶ layer was applied. -6 Under mbar pressure, 7nm MoO was deposited by vacuum evaporation. x A 60nm Au electrode was sequentially deposited as the top electrode, completing the device fabrication. The device was then subjected to EQE-current density characteristic curves and EL spectroscopy tests. Finally, an 800nm ​​near-infrared perovskite light-emitting diode with a maximum EQE of 22.2% was obtained when the perovskite dispersion concentration was 7wt% and the additive-to-lead iodide molar ratio was 0.5, achieving a maximum EQE of up to 1000mA cm⁻¹. -2 Even at current densities, it can maintain an EQE of over 10%, which is an improvement compared to undoped devices. Perovskite devices fabricated under other perovskite concentrations and additive concentrations exhibit a combination of high EQE and high emissivity in the NIR range, which is superior to previously reported perovskite, organic, and quantum dot light-emitting diodes.

[0117] Example 3: Synthesis of additives 1-4 and preparation of corresponding perovskite light-emitting diodes

[0118] The synthesis methods for additives 1-4 are as follows:

[0119]

[0120] A 30 mL solution of anhydrous aluminum trichloride (0.06 mol) in THF was rapidly added to a 25 mL solution of lithium aluminum hydride (0.06 mol) in THF under a nitrogen atmosphere, and stirred at 0 °C for 10 min. This was then added to a 15 mL solution of A4 (20 mmol) in THF, and stirred under a nitrogen atmosphere for 1 hour, followed by careful quenching with sodium sulfate decahydrate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: hexane / ethyl acetate = 7:3, v / v) and recrystallized from chloroform / methanol to give a 1-4 white powder (2.57 g, yield: 40%, purity: 99.5%). Elemental analysis calculated C 20 H 20 NOP (%): C, 74.75; H, 6.27; N, 4.36; O, 4.98; P, 9.64 Measured values: C, 74.70; H, 6.29; N, 4.37; O, 4.94; P, 9.60.

[0121] The fabrication process of perovskite light-emitting diodes doped with compounds 1-4 is as follows:

[0122] A glass substrate with an ITO conductive film was sequentially immersed in detergent, deionized water, acetone, and isopropanol, and ultrasonically cleaned for 5 minutes each, then dried and treated with oxygen plasma. ZnO nanoparticles were spin-coated onto the ITO substrate at 3000 rpm and then annealed at 150°C for 10 minutes. Subsequently, a 0.45 wt% PEIE solution dissolved in 2-methoxyethanol was spin-coated onto the ZnO electron transport layer at 5000 rpm and annealed at 100°C for 15 minutes. FAI, lead iodide, and 1-4 additive molecules were dissolved in N,N-dimethylformamide (DMF) at a molar ratio of 2.7:1:x (x = 0.1-1) to prepare a perovskite luminescent layer DMF dispersion with a concentration of 5 wt%-15 wt% of doped additives. Perovskite film deposition was then performed in a nitrogen-filled glove box. The perovskite luminescent layer was spin-coated onto a ZnO / PEIE substrate at 3000 rpm for 60 seconds, followed by annealing at 100°C for 10 minutes. On top of the perovskite luminescent layer, a poly-TPD was spin-coated at 3000 rpm for 40 seconds. Finally, a 5×10⁻⁶ layer was applied. -6 Under mbar pressure, 7nm MoO was deposited by vacuum evaporation. x A 60nm Au electrode was sequentially deposited as the top electrode, completing the device fabrication. The EQE-current density characteristic curve and EL spectrum were measured. Finally, an 800nm ​​near-infrared perovskite light-emitting diode with a maximum EQE of 22.9% was obtained when the perovskite dispersion concentration was 7wt% and the additive-to-lead iodide molar ratio was 0.5, achieving a maximum EQE of up to 1000mA cm⁻¹.-2 Even at current densities, it can maintain an EQE of over 10%, which is an improvement compared to undoped devices. Perovskite devices fabricated under other perovskite concentrations and additive concentrations exhibit a combination of high EQE and high emissivity in the NIR range, which is superior to previously reported perovskite, organic, and quantum dot light-emitting diodes.

[0123] Example 4: Synthesis of additives 1-7 and preparation of corresponding perovskite light-emitting diodes

[0124] The synthesis methods for additives 1-7 are as follows:

[0125]

[0126] A 30 mL solution of anhydrous aluminum trichloride (0.06 mol) in THF was rapidly added to a 25 mL solution of lithium aluminum hydride (0.06 mol) in THF under a nitrogen atmosphere, and stirred at 0 °C for 10 min. This was then added to a 15 mL solution of A7 (20 mmol) in THF, and stirred under a nitrogen atmosphere for 1 hour, followed by careful quenching with sodium sulfate decahydrate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: hexane / ethyl acetate = 7:3, v / v) and recrystallized from chloroform / methanol to give a white powder (1.70 g, yield: 45%, purity: 99.5%). Elemental analysis calculated C9H 10 F3N (%): C, 57.14; H, 5.33; F, 30.13; N, 7.40 Measured values: C, 57.20; H, 5.30; F, 30.17; N, 7.44.

[0127] The fabrication process of perovskite light-emitting diodes doped with compounds 1-7 is as follows:

[0128] A glass substrate with an ITO conductive film was sequentially immersed in detergent, deionized water, acetone, and isopropanol, and ultrasonically cleaned for 5 minutes each, then dried and treated with oxygen plasma. ZnO nanoparticles were spin-coated onto the ITO substrate at 3000 rpm and then annealed at 150°C for 10 minutes. Subsequently, a 0.45 wt% PEIE solution dissolved in 2-methoxyethanol was spin-coated onto the ZnO electron transport layer at 5000 rpm and annealed at 100°C for 15 minutes. FA, lead iodide, and 1-7 additive molecules were dissolved in N,N-dimethylformamide (DMF) at a molar ratio of 2.7:1:x (x = 0.1-1) to prepare a perovskite luminescent layer DMF dispersion with a concentration of 5 wt%-15 wt% of doped additives. Perovskite film deposition was then performed in a nitrogen-filled glove box. The perovskite luminescent layer was spin-coated onto a ZnO / PEIE substrate at 3000 rpm for 60 seconds, followed by annealing at 100°C for 10 minutes. On top of the perovskite luminescent layer, a poly-TPD was spin-coated at 3000 rpm for 40 seconds. Finally, a 5×10⁻⁶ layer was applied. -6 Under mbar pressure, 7nm MoO was deposited by vacuum evaporation. x A 60nm Au electrode was sequentially deposited as the top electrode, completing the device fabrication. The EQE-current density characteristic curve and EL spectrum were measured. Finally, an 800nm ​​near-infrared perovskite light-emitting diode with a maximum EQE of 23.5% was obtained when the perovskite dispersion concentration was 7wt% and the additive-to-lead iodide molar ratio was 0.5, achieving a maximum EQE of up to 1000mA cm⁻¹. -2 Even at current densities, it can maintain an EQE of over 10%, which is an improvement compared to undoped devices. Perovskite devices fabricated under other perovskite concentrations and additive concentrations exhibit a combination of high EQE and high emissivity in the NIR range, which is superior to previously reported perovskite, organic, and quantum dot light-emitting diodes.

[0129] Example 5: Synthesis of Compound 2-1 additive and preparation of corresponding perovskite light-emitting diodes

[0130] The synthesis method of compound 2-1 additive is as follows:

[0131]

[0132] A 30 mL solution of 0.06 mol anhydrous aluminum trichloride in THF was rapidly added to a 25 mL solution of 0.06 mol lithium aluminum hydride in THF under a nitrogen atmosphere, and stirred at 0 °C for 10 min. This was then added to a 15 mL solution of 20 mmol B1 in THF, and stirred for 1 hour under a nitrogen atmosphere before being carefully quenched with sodium sulfate decahydrate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: hexane / ethyl acetate = 7:3, v / v) and recrystallized from chloroform / methanol to give a 2-1 white powder (1.80 g, yield: 45%, purity: 99.5%). Elemental analysis calculated C9H 10 NO2S (%): C, 54.23; H, 6.58; N, 7.03; O, 16.06; S, 6.09 Measured values: C, 54.28; H, 6.50; N, 7.06; O, 16.05; S, 16.06.

[0133] The fabrication process of the perovskite light-emitting diode doped with compound 2-1 is as follows:

[0134] A glass substrate with an ITO conductive film was sequentially immersed in detergent, deionized water, acetone, and isopropanol, and ultrasonically cleaned for 5 minutes each, then dried and treated with oxygen plasma. ZnO nanoparticles were spin-coated onto the ITO substrate at 3000 rpm and then annealed at 150°C for 10 minutes. Subsequently, a 0.45 wt% PEIE solution dissolved in 2-methoxyethanol was spin-coated onto the ZnO electron transport layer at 5000 rpm and annealed at 100°C for 15 minutes. FAI, lead iodide, and 2-1 additive molecules were dissolved in N,N-dimethylformamide (DMF) at a molar ratio of 2.7:1:x (x = 0.1-1) to prepare a perovskite luminescent layer DMF dispersion with a concentration of 5 wt%-15 wt% of the doped additive. Perovskite film deposition was then performed in a nitrogen-filled glove box. The perovskite luminescent layer was spin-coated onto a ZnO / PEIE substrate at 3000 rpm for 60 seconds, followed by annealing at 100°C for 10 minutes. On top of the perovskite luminescent layer, a poly-TPD was spin-coated at 3000 rpm for 40 seconds. Finally, a 5×10⁻⁶ layer was applied. -6 Under mbar pressure, 7nm MoO was deposited by vacuum evaporation. x The device was fabricated by sequentially depositing 60nm Au as the top electrode. EQE-current density characteristic curves and EL spectra were then measured. Finally, an 800nm ​​near-infrared perovskite light-emitting diode with a maximum EQE of 23.3% was obtained when the perovskite dispersion concentration was 7wt% and the additive-to-lead iodide molar ratio was 0.5, achieving a maximum EQE of up to 1000mA cm⁻¹. -2Even at current densities, it can maintain an EQE of over 10%, which is an improvement compared to undoped devices. Perovskite devices fabricated under other perovskite concentrations and additive concentrations exhibit a combination of high EQE and high emissivity in the NIR range, which is superior to previously reported perovskite, organic, and quantum dot light-emitting diodes.

[0135] Example 6: Synthesis of additives 2-8 and preparation of corresponding perovskite light-emitting diodes

[0136] The synthesis method of compound 2-8 additive is as follows:

[0137]

[0138] B8 (1 mmol), ethylene glycol (20 mmol), and p-toluenesulfonic acid (TsOH, 0.05 mmol) were dissolved in toluene (15 mL) and refluxed at 130 °C for 3 hours. After the reaction was complete, the mixture was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 8:2, v / v) and recrystallized from chloroform / methanol to give B8-1 (0.26 g, yield: 98.0%, purity: 99.5%).

[0139] A 30 mL solution of 0.06 mol anhydrous aluminum trichloride in THF was rapidly added to a 25 mL solution of 0.06 mol lithium aluminum hydride in THF under a nitrogen atmosphere, and stirred at 0 °C for 10 min. This solution was then added to a 15 mL solution of 20 mmol B8-1 in THF, and stirred under a nitrogen atmosphere for 1 hour. The mixture was then carefully quenched with sodium sulfate decahydrate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 7:3, v / v), and recrystallized from chloroform / methanol to give B8-2 (2.16 g, yield: 40%, purity: 99.5%).

[0140] Concentrated hydrochloric acid (4 ml) was added to a 1 mmol THF solution (15 ml) of B8-2, and the mixture was refluxed at 60 °C for 4 hours. After the reaction was complete, the acidic reaction solution was alkalized to pH 10 with sodium carbonate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 7:3, v / v) and recrystallized from chloroform / methanol to give 2-8 white powder (0.16 g, yield: 70%, purity: 99.5%). Elemental analysis calculated C 15 H 15NO (%): C, 29.27; H, 6.71; N, 6.22; O, 7.10 Measured values: C, 29.25; H, 6.76; N, 6.26; O, 7.18.

[0141] The fabrication process of perovskite light-emitting diodes doped with compound 2-8 is as follows:

[0142] A glass substrate with an ITO conductive film was sequentially immersed in detergent, deionized water, acetone, and isopropanol, and ultrasonically cleaned for 5 minutes each, then dried and treated with oxygen plasma. ZnO nanoparticles were spin-coated onto the ITO substrate at 3000 rpm and then annealed at 150 °C for 10 minutes. Subsequently, a 0.45 wt% PEIE solution dissolved in 2-methoxyethanol was spin-coated onto the ZnO electron transport layer at 5000 rpm and annealed at 100 °C for 15 minutes. A perovskite luminescent layer DMF dispersion with a doping additive concentration of 5 wt%–15 wt% was prepared by dissolving FAI, lead iodide, and 2-8 molecules in a molar ratio of 2.7:1:x (x = 0.1–1) in N,N-dimethylformamide (DMF). Perovskite film deposition was then performed in a nitrogen-filled glove box. The perovskite luminescent layer was spin-coated onto a ZnO / PEIE substrate at 3000 rpm for 60 seconds, followed by annealing at 100°C for 10 minutes. On top of the perovskite luminescent layer, a poly-TPD was spin-coated at 3000 rpm for 40 seconds. Finally, a 5×10⁻⁶ layer was applied. -6 Under mbar pressure, 7nm MoO was deposited by vacuum evaporation. x The device was fabricated by sequentially depositing 60nm Au as the top electrode. EQE-current density characteristic curves and EL spectra were then measured. Finally, with a perovskite dispersion concentration of 7wt% and an additive-to-lead iodide molar ratio of 0.5, an 800nm ​​near-infrared perovskite light-emitting diode device with a maximum EQE of 22.8% was obtained, operating at up to 1000mA cm⁻¹. -2 Even at current densities, it can maintain an EQE of over 10%, which is an improvement compared to undoped devices. Perovskite devices fabricated under other perovskite concentrations and additive concentrations exhibit a combination of high EQE and high emissivity in the NIR range, which is superior to previously reported perovskite, organic, and quantum dot light-emitting diodes.

[0143] Example 7: Synthesis of Compound 3-1 additive and preparation of corresponding perovskite light-emitting diodes

[0144] The synthesis method of compound 3-1 additive is as follows:

[0145]

[0146] A 30 mL solution of 0.06 mol anhydrous aluminum trichloride in THF was rapidly added to a 25 mL solution of 0.06 mol lithium aluminum hydride in THF under a nitrogen atmosphere, and stirred at 0 °C for 10 min. This was then added to a 15 mL solution of 20 mmol Cl in THF, and stirred under a nitrogen atmosphere for 1 h, followed by careful quenching with sodium sulfate decahydrate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: hexane / ethyl acetate = 7:3, v / v) and recrystallized from chloroform / methanol to give a 3-1 white powder (1.40 g, yield: 35%, purity: 99.5%). Elemental analysis calculated C9H 10 NO2S (%): C, 54.23; H, 6.58; N, 7.03; O, 16.06; S, 16.09 Measured values: C, 54.28; H, 6.50; N, 7.06; O, 16.05; S, 16.06.

[0147] The fabrication process of the perovskite light-emitting diode doped with compound 3-1 is as follows:

[0148] A glass substrate with an ITO conductive film was sequentially immersed in detergent, deionized water, acetone, and isopropanol, and ultrasonically cleaned for 5 minutes each, then dried and treated with oxygen plasma. ZnO nanoparticles were spin-coated onto the ITO substrate at 3000 rpm and then annealed at 150 °C for 10 minutes. Subsequently, a 0.45 wt% PEIE solution dissolved in 2-methoxyethanol was spin-coated onto the ZnO electron transport layer at 5000 rpm and annealed at 100 °C for 15 minutes. FAI, lead iodide, and 3-1 additive molecules were dissolved in N,N-dimethylformamide (DMF) at a molar ratio of 2.7:1:x (x = 0.1-1) to prepare a perovskite luminescent layer DMF dispersion with a concentration of 5 wt%-15 wt% of the doped additive. Perovskite film deposition was then performed in a nitrogen-filled glove box. The perovskite luminescent layer was spin-coated onto a ZnO / PEIE substrate at 3000 rpm for 60 seconds, followed by annealing at 100°C for 10 minutes. On top of the perovskite luminescent layer, a poly-TPD was spin-coated at 3000 rpm for 40 seconds. Finally, a 5×10⁻⁶ layer was applied. -6 Under mbar pressure, 7nm MoO was deposited by vacuum evaporation. x The device was fabricated by sequentially depositing 60nm Au as the top electrode. EQE-current density characteristic curves and EL spectra were then measured. Finally, with a perovskite dispersion concentration of 7wt% and an additive-to-lead iodide molar ratio of 0.5, an 800nm ​​near-infrared perovskite light-emitting diode device with a maximum EQE of 23.6% was obtained, operating at up to 1000mA cm⁻¹. -2It can still maintain an EQE of over 10% at current densities, which is an improvement compared to undoped devices.

[0149] Example 8: Synthesis of Compound 3-3 additive and preparation of corresponding perovskite light-emitting diodes

[0150] The synthesis method of compound 3-3 additive is as follows:

[0151]

[0152] C3 (1 mmol), ethylene glycol (20 mmol), and p-toluenesulfonic acid (TsOH, 0.05 mmol) were dissolved in toluene (15 mL) and refluxed at 130 °C for 3 hours. After the reaction was complete, the mixture was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 8:2, v / v) and recrystallized from chloroform / methanol to give C3-1 (0.20 g, yield: 98.5%, purity: 99.5%).

[0153] A 30 mL solution of 0.06 mol anhydrous aluminum trichloride in THF was rapidly added to a 25 mL solution of 0.06 mol lithium aluminum hydride in THF under a nitrogen atmosphere, and stirred at 0 °C for 10 min. This solution was then added to a 15 mL solution of 20 mmol C3-1 in THF, and stirred under a nitrogen atmosphere for 1 hour. The mixture was then carefully quenched with sodium sulfate decahydrate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 7:3, v / v), and recrystallized from chloroform / methanol to give C3-2 (1.87 g, yield: 40%, purity: 99.5%).

[0154] Concentrated hydrochloric acid (4 ml) was added to a 1 mmol THF solution (15 ml) of C3-2, and the mixture was refluxed at 60 °C for 4 hours. After the reaction was complete, the acidic reaction solution was alkalized to pH 10 with sodium carbonate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 7:3, v / v) and recrystallized from chloroform / methanol to give a 3-3 white powder (0.11 g, yield: 70%, purity: 99.5%). Elemental analysis calculated C 10 H 13 NO (%): C, 73.59; H, 8.03; N, 8.58; O, 9.80 Measured values: C, 73.50; H, 8.07; N, 8.50; O, 9.88.

[0155] The fabrication process of the perovskite light-emitting diode doped with compound 3-3 is as follows:

[0156] A glass substrate with an ITO conductive film was sequentially immersed in detergent, deionized water, acetone, and isopropanol, and ultrasonically cleaned for 5 minutes each, then dried and etched with oxygen plasma. ZnO nanoparticles were spin-coated onto the ITO substrate at 3000 rpm and then annealed at 150°C for 10 minutes. Subsequently, a 0.45 wt% PEIE solution dissolved in 2-methoxyethanol was spin-coated onto the ZnO electron transport layer at 5000 rpm and annealed at 100°C for 15 minutes. FAI, lead iodide, and 3-3 additive molecules were dissolved in N,N-dimethylformamide (DMF) at a molar ratio of 2.7:1:x (x = 0.1-1) to prepare a perovskite luminescent layer DMF dispersion with a concentration of 5 wt%-15 wt% of doped additives. The perovskite luminescent layer was spin-coated onto a ZnO / PEIE substrate at 3000 rpm for 60 seconds and then annealed at 100°C for 10 minutes. On top of the perovskite luminescent layer, a poly-TPD was spin-coated at 3000 rpm for 40 seconds. Finally, a 5×10⁻⁶ layer was applied. -6 Under mbar pressure, 7nm MoO was deposited by vacuum evaporation. x The device was fabricated by sequentially depositing 60nm Au as the top electrode. EQE-current density characteristic curves and EL spectra were then measured. Finally, with a perovskite dispersion concentration of 7wt% and an additive-to-lead iodide molar ratio of 0.5, an 800nm ​​near-infrared perovskite light-emitting diode (LED) with a maximum EQE of 23.0% was obtained, achieving a maximum EQE of up to 1000mA cm⁻¹. -2 Even at current densities, it can maintain an EQE of over 10%, which is an improvement compared to undoped devices. Perovskite devices fabricated under other perovskite concentrations and additive concentrations exhibit a combination of high EQE and high emissivity in the NIR range, which is superior to previously reported perovskite, organic, and quantum dot light-emitting diodes.

[0157] Example 9: Synthesis of additives 4-8 and preparation of corresponding perovskite light-emitting diodes

[0158] The synthesis method of compound 4-8 additive is as follows:

[0159]

[0160] D8 (1 mmol), ethylene glycol (20 mmol), and p-toluenesulfonic acid (TsOH, 0.05 mmol) were dissolved in toluene (15 mL) and refluxed at 130 °C for 3 hours. After the reaction was complete, the mixture was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 8:2, v / v), and recrystallized from chloroform / methanol to give D8-1 (0.25 g, yield: 99.5%, purity: 99.5%).

[0161] A 30 mL solution of 0.06 mol anhydrous aluminum trichloride in THF was rapidly added to a 25 mL solution of 0.06 mol lithium aluminum hydride in THF under a nitrogen atmosphere, and stirred at 0 °C for 10 min. This solution was then added to a 15 mL solution of 20 mmol D8-1 in THF, and stirred for 1 hour under a nitrogen atmosphere before being carefully quenched with sodium sulfate decahydrate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 7:3, v / v) and recrystallized from chloroform / methanol to give D8-2 (2.56 g, yield: 50%, purity: 99.5%).

[0162] Concentrated hydrochloric acid (4 ml) was added to a 1 mmol THF solution (15 ml) of D8-2, and the mixture was refluxed at 60 °C for 4 hours. After the reaction was complete, the acidic reaction solution was alkalized to pH 10 with sodium carbonate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 7:3, v / v) and recrystallized from chloroform / methanol to give 4-8 white powder (0.14 g, yield: 65%, purity: 99.5%). Elemental analysis calculated C 14 H 13 NO (%): C, 79.59; H, 6.20; N, 6.63; O, 7.57 Measured values: C, 79.52; H, 6.22; N, 6.64; O, 7.59.

[0163] The fabrication process of perovskite light-emitting diodes doped with compound 4-8 is as follows:

[0164] A glass substrate with an ITO conductive film was sequentially immersed in detergent, deionized water, acetone, and isopropanol, and ultrasonically cleaned for 5 minutes each, then dried and treated with oxygen plasma. ZnO nanoparticles were spin-coated onto the ITO substrate at 3000 rpm and then annealed at 150 °C for 10 minutes. Subsequently, a 0.45 wt% PEIE solution dissolved in 2-methoxyethanol was spin-coated onto the ZnO electron transport layer at 5000 rpm and annealed at 100 °C for 15 minutes. FAI, lead iodide, and 4-8 additive molecules were dissolved in N,N-dimethylformamide (DMF) at a molar ratio of 2.7:1:x (x = 0.1-1) to prepare a perovskite luminescent layer DMF dispersion with a concentration of 5 wt%-15 wt% of the doped additives. Perovskite film deposition was then performed in a nitrogen-filled glove box. The perovskite luminescent layer was spin-coated onto a ZnO / PEIE substrate at 3000 rpm for 60 seconds, followed by annealing at 100°C for 10 minutes. On top of the perovskite luminescent layer, a poly-TPD was spin-coated at 3000 rpm for 40 seconds. Finally, a 5×10⁻⁶ layer was applied. -6 Under mbar pressure, 7nm MoO was deposited by vacuum evaporation. x The device was fabricated by sequentially depositing 60nm Au as the top electrode. EQE-current density characteristic curves and EL spectra were then measured. Finally, with a perovskite dispersion concentration of 7wt% and an additive-to-lead iodide molar ratio of 0.5, an 800nm ​​near-infrared perovskite light-emitting diode (LED) with a maximum EQE of 23.0% was obtained, achieving a maximum EQE of up to 1000mA cm⁻¹. -2 Even at current densities, it can maintain an EQE of over 10%, which is an improvement compared to undoped devices. Perovskite devices fabricated under other perovskite concentrations and additive concentrations exhibit a combination of high EQE and high emissivity in the NIR range, which is superior to previously reported perovskite, organic, and quantum dot light-emitting diodes.

[0165] Example 10: Synthesis of Compound 5-4 additive and preparation of corresponding perovskite light-emitting diodes

[0166] The synthesis method of compound 5-4 additive is as follows:

[0167]

[0168] A 30 mL solution of anhydrous aluminum trichloride (0.06 mol) in THF was rapidly added to a 25 mL solution of lithium aluminum hydride (0.06 mol) in THF under a nitrogen atmosphere, and stirred at 0 °C for 10 minutes. This was then added to a 15 mL solution of E4 (20 mmol) in THF, and stirred under a nitrogen atmosphere for 1 hour, followed by careful quenching with sodium sulfate decahydrate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: hexane / ethyl acetate = 7:3, v / v) and recrystallized from chloroform / methanol to give a 5-4 white powder (3.15 g, yield: 45%, purity: 99.5%). Elemental analysis calculated C. 22 H 24 NOP (%): C, 75.62; H, 6.92; N, 4.01; O, 4.58; P, 8.86 Measured values: C, 75.60; H, 6.90; N, 4.05; O, 4.55; P, 8.80.

[0169] The fabrication process of the perovskite light-emitting diode doped with compound 1-1 is as follows:

[0170] A glass substrate with an ITO conductive film was sequentially immersed in detergent, deionized water, acetone, and isopropanol, and ultrasonically cleaned for 5 minutes each, then dried and treated with oxygen plasma etching. ZnO nanoparticles were spin-coated onto the ITO substrate at 3000 rpm and then annealed at 150°C for 10 minutes. Subsequently, a 0.45 wt% PEIE solution dissolved in 2-methoxyethanol was spin-coated onto the ZnO electron transport layer at 5000 rpm and annealed at 100°C for 15 minutes. FAI, lead iodide, and 5-4 additive molecules were dissolved in N,N-dimethylformamide (DMF) at a molar ratio of 2.7:1:x (x = 0.1-1) to prepare a perovskite luminescent layer DMF dispersion with a concentration of 5 wt%-15 wt% of doped additives. Perovskite film deposition was then performed in a nitrogen-filled glove box. A perovskite luminescent layer was deposited on a ZnO / PEIE substrate at 3000 rpm for 60 seconds, followed by annealing at 100°C for 10 minutes. On top of the perovskite luminescent layer, a poly-TPD coating was spin-coated at 3000 rpm for 40 seconds. Finally, a 5×10⁻⁶ layer was applied. -6 Under mbar pressure, 7nm MoO was deposited by vacuum evaporation. x The device was fabricated by sequentially depositing 60nm Au as the top electrode. EQE-current density characteristic curves and EL spectra were then measured. Finally, with a perovskite dispersion concentration of 7wt% and an additive-to-lead iodide molar ratio of 0.5, an 800nm ​​near-infrared perovskite light-emitting diode (LED) with a maximum EQE of 23.1% was obtained, operating at up to 1000mA cm⁻¹.-2 It can still maintain an EQE of over 10% at current densities, which is an improvement compared to undoped devices.

[0171] Example 11: Synthesis of Compound 6-4 additive and preparation of corresponding perovskite light-emitting diodes

[0172] The synthesis method of compound 6-4 additive is as follows:

[0173]

[0174] A 30 mL solution of 0.06 mol anhydrous aluminum trichloride in THF was rapidly added to a 25 mL solution of 0.06 mol lithium aluminum hydride in THF under a nitrogen atmosphere, and stirred at 0 °C for 10 min. This was then added to a 15 mL solution of 20 mmol F3 in THF, and stirred under a nitrogen atmosphere for 1 hour, followed by careful quenching with sodium sulfate decahydrate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: hexane / ethyl acetate = 7:3, v / v) and recrystallized from chloroform / methanol to give a white powder (3.02 g, yield: 45%, purity: 99.5%). Elemental analysis calculated C 21 H 22 NOP (%): C, 75.21; H, 6.61; N, 4.18; O, 4.77; P, 9.24 Measured values: C, 75.20; H, 6.63; N, 4.16; O, 4.76; P, 9.26.

[0175] The fabrication process of perovskite light-emitting diodes doped with compound 6-4 is as follows:

[0176] A glass substrate with an ITO conductive film was sequentially immersed in detergent, deionized water, acetone, and isopropanol, and ultrasonically cleaned for 5 minutes each, then dried and treated with oxygen plasma. ZnO nanoparticles were spin-coated onto the ITO substrate at 3000 rpm and then annealed at 150°C for 10 minutes. Subsequently, a 0.45 wt% PEIE solution dissolved in 2-methoxyethanol was spin-coated onto the ZnO electron transport layer at 5000 rpm and annealed at 100°C for 15 minutes. FAI, lead iodide, and 6-4 additive molecules were dissolved in N,N-dimethylformamide (DMF) at a molar ratio of 2.7:1:x (x = 0.1-1) to prepare a perovskite luminescent layer DMF dispersion with a concentration of 5 wt%-15 wt% of the doped additive. Perovskite film deposition was then performed in a nitrogen-filled glove box. The perovskite luminescent layer was spin-coated onto a ZnO / PEIE substrate at 3000 rpm for 60 seconds, followed by annealing at 100°C for 10 minutes. On top of the perovskite luminescent layer, a poly-TPD was spin-coated at 3000 rpm for 40 seconds. Finally, a 5×10⁻⁶ layer was applied. -6 Under mbar pressure, 7nm MoO was deposited by vacuum evaporation. x The device was fabricated by sequentially depositing 60nm Au as the top electrode. EQE-current density characteristic curves and EL spectra were then measured. Finally, with a perovskite dispersion concentration of 7wt% and an additive-to-lead iodide molar ratio of 0.5, an 800nm ​​near-infrared perovskite light-emitting diode with a maximum EQE of 23.3% was obtained, operating at up to 1000mA cm⁻¹. -2 It can still maintain an EQE of over 10% at current densities, which is an improvement compared to undoped devices.

[0177] Example 12: Synthesis of Compound 7-3 additive and preparation of corresponding perovskite light-emitting diodes

[0178] The synthesis method of compound 7-3 additive is as follows:

[0179]

[0180] G3 (1 mmol), ethylene glycol (20 mmol), and p-toluenesulfonic acid (TsOH, 0.05 mmol) were dissolved in toluene (15 mL) and refluxed at 130 °C for 3 hours. After the reaction was complete, the mixture was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 8:2, v / v), and recrystallized from chloroform / methanol to give G3-1 (0.24 g, yield: 97.8%, purity: 99.5%).

[0181] A 30 mL solution of 0.06 mol anhydrous aluminum trichloride in THF was rapidly added to a 25 mL solution of 0.06 mol lithium aluminum hydride in THF under a nitrogen atmosphere, and stirred at 0 °C for 10 min. This solution was then added to a 15 mL solution of 20 mmol G3-1 in THF, and stirred for 1 hour under a nitrogen atmosphere before being carefully quenched with sodium sulfate decahydrate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 7:3, v / v), and recrystallized from chloroform / methanol to give G3-2 (2.25 g, yield: 45%, purity: 99.5%).

[0182] Concentrated hydrochloric acid (4 ml) was added to a 1 mmol THF solution (15 ml) of G3-2, and the mixture was refluxed at 60 °C for 4 hours. After the reaction was complete, the acidic reaction solution was alkalized to pH 10 with sodium carbonate. The product was extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. The crude product was filtered and evaporated, then purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 7:3, v / v) and recrystallized from chloroform / methanol to give 7-3 white powder (0.14 g, yield: 70%, purity: 99.5%). Elemental analysis calculated C 13 H 19 NO (%): C, 76.06; H, 9.33; N, 6.82; O, 7.79 Measured values: C, 76.04; H, 9.35; N, 6.86; O, 7.76.

[0183] The fabrication process of the perovskite light-emitting diode doped with compound 7-3 is as follows:

[0184] A glass substrate with an ITO conductive film was sequentially immersed in detergent, deionized water, acetone, and isopropanol, and ultrasonically cleaned for 5 minutes each, then dried and treated with oxygen plasma. ZnO nanoparticles were spin-coated onto the ITO substrate at 3000 rpm and then annealed at 150°C for 10 minutes. Subsequently, a 0.45 wt% PEIE solution dissolved in 2-methoxyethanol was spin-coated onto the ZnO electron transport layer at 5000 rpm and annealed at 100°C for 15 minutes. FAI, lead iodide, and 7-3 additive molecules were dissolved in N,N-dimethylformamide (DMF) at a molar ratio of 2.7:1:x (x = 0.1-1) to prepare a perovskite luminescent layer DMF dispersion with a concentration of 5 wt%-15 wt% of the doped additive. Perovskite film deposition was then performed in a nitrogen-filled glove box. The perovskite luminescent layer was spin-coated onto a ZnO / PEIE substrate at 3000 rpm for 60 seconds, followed by annealing at 100°C for 10 minutes. On top of the perovskite luminescent layer, a poly-TPD was spin-coated at 3000 rpm for 40 seconds. Finally, a 5×10⁻⁶ layer was applied. -6 Under mbar pressure, 7nm MoO was deposited by vacuum evaporation. x The device was fabricated by sequentially depositing 60nm Au as the top electrode. EQE-current density characteristic curves and EL spectra were then measured. Finally, with a perovskite dispersion concentration of 7wt% and an additive-to-lead iodide molar ratio of 0.5, an 800nm ​​near-infrared perovskite light-emitting diode device with a maximum EQE of 23.4% was obtained, operating at up to 1000mA cm⁻¹. -2 Even at current densities, it can maintain an EQE of over 10%, which is an improvement compared to undoped devices. Perovskite devices fabricated under other perovskite concentrations and additive concentrations exhibit a combination of high EQE and high emissivity in the NIR range, which is superior to previously reported perovskite, organic, and quantum dot light-emitting diodes.

[0185] Example 13

[0186] The perovskite light-emitting diode in Example 13 was prepared by the same method as in Example 1, except that the concentration of compound 1-1 additive was 0.1, that is, the molar ratio of FAI, lead iodide and 1-1 additive molecules was 2.7:1:0.1.

[0187] Example 14

[0188] The perovskite light-emitting diode in Example 14 was prepared by the same method as in Example 1, except that the concentration of compound 1-1 additive was 1.0, that is, the molar ratio of FAI, lead iodide and 1-1 additive molecules was 2.7:1:1.0.

[0189] Example 15

[0190] The perovskite light-emitting diode in Example 15 was prepared using the same method as in Example 1, except that the concentration of the DMF dispersion of the doped perovskite light-emitting layer was 5 wt%.

[0191] Example 16

[0192] The perovskite light-emitting diode in Example 16 was prepared using the same method as in Example 1, except that the concentration of the DMF dispersion of the doped perovskite light-emitting layer was 15 wt%.

[0193] Comparative Example 1

[0194] The perovskite light-emitting diode in Comparative Example 1 was prepared using the same method as the perovskite light-emitting diode in Example 1, except that no additives were used in the perovskite light-emitting layer.

[0195] Comparative Example 2

[0196] The perovskite light-emitting diode in Comparative Example 2 was prepared using the same method as that in Example 1, except that phenylethylamine (PEA) was used as an additive in the perovskite light-emitting layer.

[0197] The specific structures of the compounds involved in the above embodiments are as follows:

[0198] The current-luminance-voltage characteristics of the perovskite light-emitting diode devices doped with the additives of the corresponding embodiments were obtained using a Keithley source measurement system (Keithley 2400 Sourcemeter, Keithley 2000 Currentmeter) with a calibrated silicon photodiode. Electroluminescence spectra were measured using a Photo Research PR655 spectrometer. The external quantum efficiency of the perovskite light-emitting diode devices was calculated using the method described in Adv. Mater., 2003, 15, 1043-1048. A summary of the performance of the perovskite light-emitting diode devices in the above embodiments and the comparative examples is shown in Table 1.

[0199] Table 1

[0200]

[0201] Among them, the lifetime of perovskite light-emitting diodes is at an initial brightness of 100W sr. -1 m -2The following measurements are taken: the perovskite concentration is the mass concentration of the DMF dispersion of the perovskite luminescent layer prepared by spin coating to prepare a perovskite luminescent layer doped with a bifunctional multifunctional additive; the additive concentration is the specific value of x when FAI, lead iodide and dopant molecules are dissolved in N,N-dimethylformamide (DMF) in a molar ratio of 2.7∶1∶x (x=0.1-1) during the preparation of the perovskite luminescent layer.

[0202] As shown in Table 1, compared to perovskite LEDs with undoped light-emitting layers (Comparative Example 1) and perovskite LEDs with amino monofunctional groups (PEA, phenylethylamine) as dopants (Comparative Example 2), the additive molecules provided in this disclosure improve crystallinity and reduce various defects by introducing lone pair electrons (including N, O, halogens, etc.) to form intermolecular hydrogen bonds with amino groups. Furthermore, they can assemble between perovskite particles, forming a physical spacer layer between charge transport layers in the device to eliminate luminescence quenching at the interface. Ultimately, this results in superior EQE and lifespan at high current densities. Figure 5 Compared to perovskite light-emitting diodes prepared without additives ( Figure 4 ).

[0203] Furthermore, by changing the composition and content of the multifunctional additives in this embodiment, the photoelectric luminescence efficiency, grain growth rate during perovskite film formation, and uniformity of the perovskite film can be controlled. This allows for the fabrication of near-infrared perovskite light-emitting diodes that achieve high EQE at higher brightness and current densities, while also extending the lifespan of existing diodes at higher current densities.

[0204] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A perovskite thin film containing a bifunctional additive, said perovskite thin film being formed by reacting formamidinium hydroiodate, lead iodide, and said bifunctional additive, wherein, The bifunctional additive has a structure as shown in formula (1): Equation (1); A1 is selected from C1-C5 alkyl groups; X includes any of the following lone pair electron groups: 、 、 、 、 ； Wherein, the lone pair electron group is in the para position with the amino group in formula (1) and forms an intermolecular hydrogen bond self-assembly structure as a physical spacer layer, and the lone pair electron group serves as a Lewis base to passivate the unsaturated lead dangling bonds in the perovskite film. The formation of hydrogen bonds or intermolecular forces between the amino group and the amino group of the formamidinium hydroiodate weakens the interaction between the formamidinium hydroiodate and the perovskite film.

2. The perovskite thin film according to claim 1, wherein, The alkyl group in the bifunctional additive includes -CH2-CH2-.

3. The perovskite thin film according to claim 1, wherein, The bifunctional additive includes any one of the following: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 。 4. A perovskite light-emitting diode based on FAPbI3, wherein the perovskite light-emitting diode comprises, from bottom to top: A glass substrate with an ITO conductive thin film, an electron transport layer, a modification layer, a FAPbI3-based perovskite light-emitting layer, a hole transport layer, a hole injection layer, and electrodes; The perovskite luminescent layer based on FAPbI3 is a three-dimensional cubic phase FAPbI3 perovskite luminescent layer, which is composed of formamidinium hydroiodate, lead iodide and bifunctional additives in the perovskite film according to any one of claims 1-3. The molar ratio of formamidin hydroiodide, lead iodide, and additives is 2.7:1:x, where x = 0.1-1.

5. The perovskite light-emitting diode according to claim 4, wherein: The electron transport layer comprises: ZnO; The modification layer includes: ethoxylated polyethyleneimine; The hole transport layer comprises: poly[bis(4-phenyl)(4-butylphenyl)amine] or poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)]; The hole injection layer includes molybdenum oxide; The electrode includes any one of Au, Ag, Cu, and Al.

6. The perovskite light-emitting diode according to claim 5, wherein: The thickness of the electron transport layer is 30-50 nm; The thickness of the modification layer is 0.1-2 nm; The thickness of the FAPbI3-based perovskite luminescent layer is 10-50 nm; The thickness of the hole transport layer is 20-60 nm; The thickness of the hole injection layer is 5-10 nm; The thickness of the electrode is 50-200 nm.

7. A method for manufacturing a perovskite light-emitting diode according to any one of claims 4-6, comprising: Step 1: Clean the glass substrate with the ITO conductive film and perform plasma treatment. Step 2: On a glass substrate with an ITO conductive thin film after plasma treatment, an electron transport layer, a modification layer, and a perovskite light-emitting layer based on FAPbI3 are sequentially prepared by spin coating. Step 3: On the FAPbI3-based perovskite light-emitting layer, a hole transport layer is prepared sequentially by spin coating, and a hole injection layer and an electrode are deposited by vacuum evaporation. The FAPbI3-based perovskite luminescent layer includes: Formamidinium hydroiodate, lead iodide, and bifunctional additives in perovskite films according to any one of claims 1-3; The molar ratio of formamidinium hydroiodate, lead iodide, and bifunctional additive is 2.7:1:x, where x = 0.1-1.

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