Polydentate organic ligand modified perovskite luminescent material, and preparation method and application thereof

Abstract

The invention relates to the technical field of photoelectric materials, in particular to a polydentate organic ligand modified perovskite luminescent material and a preparation method and application thereof. According to the multi-tooth organic ligand modified perovskite luminescent material, octahedral unit cells formed by divalent lead ions, Cs < + > and halide ions form a multi-layer lead-based perovskite structure in an angle sharing mode, and the layers are spaced through organic ammonium cations. And an organic amidoxime compound is adopted as a polydentate organic ligand and is modified on the surface of the perovskite layer together with a passivating agent, so that surface defects are effectively passivated, and a multi-phase mixed quasi-two-dimensional lead-based perovskite system is constructed. According to the invention, the organic amidoxime compound is used as a polydentate organic ligand and a passivator and is used for modifying the quasi-two-dimensional perovskite luminescent material, and the modified material has smooth film morphology, low defect state density and improved PLQY.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photoelectric materials, in particular to a perovskite light-emitting material modified by a multi-dentate organic ligand, a preparation method and application thereof. BACKGROUND

[0002] Organic-inorganic hybrid perovskite materials have shown broad application prospects in photovoltaic devices, light-emitting diodes, photodetectors and lasers due to their strong light absorption coefficient, adjustable band gap, good solution processability, high carrier mobility and low cost. However, the commercialization process of perovskite light-emitting diodes still faces severe challenges.

[0003] So far, the efficiencies of perovskite green and red devices have both broken through 30% in the three primary colors of solid-state white light illumination, such as document 1: Adv. Mater. 2024, 36, e2400421; Adv. Mater. 2025, e2503683 and document 2: Adv. Mater. 2024, 36, e2410255; while the efficiency of blue devices still lags far behind. The key problem lies in the intrinsic wide band gap emission characteristics of blue light, which not only leads to low carrier injection efficiency, but also the complex crystal phase structure of perovskite induces high-density defect states, hindering energy transport and carrier recombination. Therefore, not only is it difficult to improve the efficiency of blue devices, but also the phase separation and ion migration behavior in organic-inorganic hybrid perovskite materials and devices leads to a sharp decline in working life, which becomes a fatal bottleneck for industrial application.

[0004] Organic ligands, as a key component of organic-inorganic perovskite materials, play a core role in defect passivation, phase distribution regulation, thin film morphology optimization and energy level arrangement. Therefore, designing and introducing ligands with special functional groups has become a research hotspot to improve the performance of perovskite materials and devices. Although the commonly used chain ligands can provide certain passivation effect, their large spatial structure will reduce the carrier mobility in quasi-two-dimensional perovskite, and limit the effective use of more coordination sites, resulting in low efficiency of perovskite devices. On the other hand, small molecule monodentate ligands have poor stability due to the single functional group, which limits their application in high-efficiency perovskite devices. SUMMARY

[0005] To solve the above technical problems, the present application provides a perovskite light-emitting material modified by a multi-dentate organic ligand, a preparation method and application thereof.

[0006] The present application aims to develop a new type of ligand with compact structure and multiple coordination sites, for realizing efficient defect passivation, improving film quality and phase distribution, and ultimately improving the efficiency and stability of perovskite devices, which has important scientific research and practical value, and solves the problems of low external quantum efficiency and low stability of existing perovskite luminescent materials prepared by organic ligands in corresponding devices.

[0007] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows.

[0008] The present application provides a perovskite luminescent material modified by a polydentate organic ligand in the first aspect, which is formed by divalent lead ions, Cs + and halogen ions to form a perovskite octahedral cell, which forms a multi-layer lead-based perovskite layer through corner sharing, and the lead-based perovskite layers are separated by organic ammonium cation layers, and an organic amide oxime compound is used as a polydentate organic ligand and a passivation agent to modify the surface of the lead-based perovskite layer, passivate surface defects, construct a quasi-two-dimensional lead-based perovskite system with multiple phase mixing, and obtain a perovskite luminescent material modified by a polydentate organic ligand.

[0009] The present application uses an organic amide oxime compound as a polydentate organic ligand and a passivation agent to prepare a perovskite luminescent material modified by a polydentate organic ligand, and the modified perovskite luminescent material has smooth film morphology, low defect state density and improved PLQY.

[0010] The use of the polydentate organic ligand of the present application promotes the synthesis of a perovskite luminescent material modified by a polydentate organic ligand with improved performance. The structural characteristics of the lead-based perovskite are that the octahedral cells formed by divalent lead ions and halogen ions form lead-based perovskite layers of different thicknesses through corner sharing, and the different lead-based perovskite layers are separated by PEA + and EA + These two organic ammonium cations are separated, PEA + represents a phenethylammonium cation; EA + represents an ethylammonium cation. The polydentate organic ligand can be uniformly attached to the surface of the lead-based perovskite layer, making up for surface defect states, and forming a quasi-two-dimensional perovskite structure with multiple phase mixing. The performance characteristics of the lead-based perovskite are that its energy follows a funnel-shaped transmission mode from small n phase to large n phase, the band gap width of the perovskite luminescent material can be 2.50eV-2.60eV, the fluorescence emission wavelength can be 476nm-495nm, and the quantum fluorescence yield is relatively high.

[0011] Preferably, the organic amide oxime compound has any one of the structural formulas as shown below: ; wherein R is selected from at least one of hydrogen, fluorine, chlorine, iodine and methyl.

[0012] In the present application, the benzene ring on the organic amide oxime compound can be replaced by a heterocycle such as a thiophene group. R is a substituent on the benzene ring, and the substitution sites include ortho, meta and para positions.

[0013] Preferably, the polydentate organic ligand is a compound HBMA or a compound 3FHBMA as shown below: .

[0014] Preferably, the organic ammonium cation layer is a mixture of phenethylammonium cations and ethylammonium cations; the lead-based perovskite layer is an octahedral cell array composed of Cs + , Pb 2+ and X - ions, wherein X is a halide ion, and the halide ion is at least one of Br - , Cl - and I - .

[0015] The present application uses a lead-based perovskite as the research object, which can better induce the formation of perovskite octahedral cells, and further form a lead-based perovskite layer in an angle-sharing manner. The general formula of the perovskite light-emitting material modified by the polydentate organic ligand is (L) z PEA y EA 2−y (CsPbX3) n−1 PbX4; wherein L is an organic amide oxime compound; PEA + is a phenethylammonium cation; EA + is an ethylammonium cation; X is a halide; and n is the number of layers of perovskite octahedrons between adjacent organic ammonium cation layers.

[0016] The present application uses an organic amide oxime compound as a polydentate organic ligand and a passivator. The structural characteristics of the polydentate organic ligand are small molecular space structure, and the presence of both oxime groups and amino groups, multiple coordination sites, and conjugated connection of oxygen atoms and nitrogen atoms with high electronegativity, which form a high electron cloud concentration area in the substitution area of the aromatic ring. The polydentate organic ligand can not only coordinate with unsaturated lead ions, but also facilitate the formation of hydrogen bonds with various organic ammonium cations in the perovskite system, inhibit the diffusion speed of the organic ammonium cations, adjust the phase distribution, and promote the smoothness of the film morphology. The organic amide oxime compound of the present application can be a benzamide oxime compound or a thiophene amide oxime compound. The synthesis of the polydentate organic ligand of the present application uses inexpensive commercial raw materials containing cyano functional groups, which has good economic efficiency and industrialization potential.

[0017] Preferably, the preparation method of the organic amide oxime compound comprises the following steps: The cyano-containing compound shown in formula i-1 or formula i-2 is reacted with hydroxylamine under the condition of triethylamine to prepare the organic amide oxime compound shown in formula ii-1 or formula ii-2.

[0018] The synthetic reaction formula is as follows: .

[0019] The specific preparation method of the organic amide oxime compound is as follows: The cyano-containing compound shown in formula i-1 or formula i-2 is dissolved in an alcohol solvent under a nitrogen atmosphere, and after stirring and mixing, an aqueous hydroxylamine solution is added, and stirring reaction is carried out, and after purification treatment, the organic amide oxime compound shown in formula ii-1 or formula ii-2 is obtained.

[0020] Preferably, the molar ratio of the cyano-containing compound shown in formula i-1 or formula i-2 to triethylamine is 1:1.2-1.5; and the molar ratio of the cyano-containing compound shown in formula i-1 or formula i-2 to hydroxylamine is 1:1.2-1.5.

[0021] Preferably, the concentration of the aqueous hydroxylamine solution is 50wt%. Preferably, the reaction conditions for preparing the organic amide oxime compound are that the reaction temperature is 80-85℃, and the reaction time is 2-4h.

[0022] Preferably, the specific operation of the purification treatment is: after cooling to room temperature, the reaction mixture is concentrated under vacuum, and then purified by silica gel column chromatography, and the elution solvent is petroleum ether and ethyl acetate, which is gradient eluted according to 20:1-2:1; and the organic amide oxime compound shown in formula ii-1 or formula ii-2 is obtained.

[0023] The second aspect of the present application provides a preparation method of the perovskite light-emitting material modified by the multi-dentate organic ligand according to the first aspect, comprising the following steps: The PbX2, CsX, EAX, PEAX and the organic amide oxime compound are stirred and mixed with an organic solvent under an inert atmosphere, filtered to obtain a precursor solution; the precursor solution is spin-coated on a substrate to prepare a precursor film on the substrate; and the substrate with the precursor film is subjected to annealing treatment to obtain the perovskite light-emitting material modified by the multi-dentate organic ligand.

[0024] The present application applies the multi-dentate organic ligand L to the synthesis of a new light-emitting film by preparing a precursor solution and a simple spin-coating method, which is simple and easy to operate. In the present application, the inert atmosphere is a nitrogen atmosphere.

[0025] Preferably, the molar ratio of PbX2, CsX, EAX, PEAX and organic amide oxime compounds is 1:0.9-1.1:0.55:0.5:0.01-0.1.

[0026] Preferably, the concentration of the polydentate organic ligand in the precursor solution is 0.7 mmol / L-12 mmol / L. The control of the molar concentration corresponds to the control of the perovskite luminescence performance, which can be more easily prepared and operated through the conversion of mass.

[0027] Preferably, PbX2, CsX, EAX, PEAX and organic amide oxime compounds are used as precursor drugs, and the mass concentration of the precursor drugs in the precursor solution is 51.06 mg / mL-89.12 mg / mL. By controlling the concentration of solutes in the precursor solution, the emission wavelength and performance of the luminescent material can be reasonably adjusted.

[0028] Preferably, the annealing temperature is 60℃-150℃, and the annealing time is 0.5 min-20 min. After spin coating, it is quickly transferred to a high-temperature annealing table for annealing treatment, which accelerates the volatilization of the solvent and the crystallization and shaping of the perovskite luminescent layer.

[0029] Preferably, the organic solvent is N,N-dimethylformamide and / or dimethyl sulfoxide. The usage ratio of PbX2 to the organic solvent is 0.1 mmol:0.833 mL-1.43 mL. The use of high-polarity aprotic solvents N,N-dimethylformamide or dimethyl sulfoxide can ensure the sufficient dissolution of inorganic and organic solutes.

[0030] Preferably, the spin coating speed is 3000 rpm-5000 rpm, and the spin coating time is 30 s-120 s. The usage amount of the precursor solution used in spin coating is 100 microliters-200 microliters. The control of the spin coating speed and the spin coating time can directly affect the thickness and morphology of the perovskite luminescent film.

[0031] The temperature for stirring and mixing is room temperature, and the stirring and mixing time is 3 h-8 h. The sufficient stirring and mixing time can ensure the complete dissolution of the solutes.

[0032] The third aspect of the present application provides a use of the perovskite luminescent material modified by the polydentate organic ligand of the first aspect in the preparation of a device containing a quasi-two-dimensional lead-based perovskite structure.

[0033] The external quantum efficiency of the high-efficiency sky blue light device prepared from the perovskite light-emitting material modified by the polydentate organic ligand of the application can reach more than 15%, and the introduction of the polydentate organic ligand enables the prepared polydentate organic ligand-modified perovskite light-emitting material to exhibit better energy level matching and carrier injection, which is of great significance to the improvement of the device performance.

[0034] Preferably, the device is a photoluminescence device, an electroluminescence device or a solar cell device.

[0035] The polydentate organic ligand-modified perovskite light-emitting material of the application can effectively passivate perovskite defects, adjust phase distribution and perovskite energy levels, form a smooth film morphology and improve the performance of perovskite in photoluminescence devices, electroluminescence devices and solar cells.

[0036] The polydentate organic ligand-modified perovskite light-emitting material of the application also exhibits good energy level adjustment when used in a blue light device, suppresses electron transport, promotes hole injection, and significantly improves the performance and service life of the device, which provides great reference for the further application of benzamide oxime organic ligands in high-efficiency perovskite devices.

[0037] Advantages of the application: 1. The organic amide oxime compound is used as a polydentate organic ligand and a passivation agent to prepare a polydentate organic ligand-modified perovskite light-emitting material, and the modified perovskite light-emitting material has a smooth film morphology, a low defect state density and improved PLQY.

[0038] 2. The lead-based perovskite is used as a research object in the application, which can better induce the formation of an octahedral cell and further form a lead-based perovskite layer in an angle-sharing manner. The polydentate organic ligand of the application has the structural characteristics of a small molecular space structure, and contains both oxime groups and amino groups, has multiple coordination sites, and the oxygen atoms and nitrogen atoms with high electronegativity are conjugated, forming a high electron cloud concentration area in the substitution area of the aromatic ring. The polydentate organic ligand can not only coordinate with unsaturated lead ions, but also form hydrogen bonds with various organic ammonium cations in the perovskite system, inhibit their diffusion speed, adjust the phase distribution and promote the smoothness of the film morphology.

[0039] 3. The polydentate organic ligand is used as a passivation agent, and the use of the passivation agent promotes the synthesis of a polydentate organic ligand-modified perovskite light-emitting material with improved performance. The structural characteristics of the perovskite are that the octahedral cells formed by divalent lead ions and halogen ions form perovskite layers with different thicknesses in an angle-sharing manner, and the PEA +, EA + The organic ammonium cations are spaced apart, and the multidentate organic ligand L can be uniformly attached to the surface of the perovskite layer, fill the surface defect state, and form a multi-phase mixed quasi-two-dimensional perovskite structure. The energy of the multi-phase mixed quasi-two-dimensional perovskite structure of the application follows a funnel-shaped transmission mode from a small n phase to a large n phase, the material band gap width can be 2.50eV-2.60eV, the fluorescent emission wavelength can be 476nm-495nm, and the quantum fluorescent yield is relatively high.

[0040] 4、The external quantum efficiency of the high-efficiency sky blue light device prepared from the perovskite light-emitting material modified by the multidentate organic ligand can reach more than 15%, and the introduction of the multidentate organic ligand L enables the perovskite light-emitting material modified by the multidentate organic ligand to exhibit good energy level matching and carrier injection, which is of great significance for improving the performance of the device. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 It is a schematic diagram of the molecular structure of HBMA in Example 1.

[0042] Figure 2 It is an absorption spectrum diagram of the blue light perovskite light-emitting film prepared in Example 1.

[0043] Figure 3 It is a photoluminescence spectrum diagram of the blue light perovskite light-emitting film prepared in Example 1.

[0044] Figure 4 It is a fluorescence quantum yield spectrum of the blue light perovskite light-emitting film prepared in Example 1.

[0045] Figure 5 It is a scanning electron microscope spectrum of the perovskite film added with HBMA in Example 1 and the standard control film without adding HBMA.

[0046] Figure 6 It is an external quantum efficiency diagram of the electroluminescent device prepared from the blue light perovskite light-emitting film of Example 1 and the standard control device prepared from the perovskite light-emitting film without adding HBMA.

[0047] Figure 7 It is a working time diagram of the electroluminescent device prepared from the blue light perovskite light-emitting film of Example 1 and the standard control device prepared from the perovskite light-emitting film without adding HBMA.

[0048] Figure 8 It is a photoluminescence spectrum diagram of the blue light perovskite light-emitting film prepared in Example 2.

[0049] Figure 9 It is a scanning electron microscope spectrum of the perovskite film added with HBMA in Example 2 and the standard control film without adding HBMA.

[0050] Figure 10 The external quantum efficiency plot of the electroluminescent device prepared from the blue light perovskite light-emitting thin film of Example 2 and the standard control device prepared from the perovskite light-emitting thin film without adding HBMA.

[0051] Figure 11 The schematic diagram of the molecular structure of 3FHBMA in Example 3.

[0052] Figure 12 The photoluminescence spectrum plot of the blue light perovskite light-emitting thin film prepared in Example 3.

[0053] Figure 13 The scanning electron microscope plot of the perovskite thin film with 3FHBMA in Example 3 and the standard control thin film without adding 3FHBMA.

[0054] Figure 14 The external quantum efficiency plot of the electroluminescent device prepared from the blue light perovskite light-emitting thin film of Example 3 and the standard control device prepared from the perovskite light-emitting thin film without adding 3FHBMA. DETAILED DESCRIPTION

[0055] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to examples. It should be understood that the specific examples described herein are only used to explain the present application and not used to limit the present application.

[0056] Based on the examples in the present application, all other examples obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present application.

[0057] In the organic-inorganic perovskite low-dimensional structure, when excited by photons or injected with a large amount of energy, the electrons and holes will preferentially combine to form excitons under the strong constraint of the low n phase, the excitons carry energy from the small n phase to the large n phase, and realize light emission in the form of radiative recombination. The intrinsic quantum well of the organic-inorganic perovskite low-dimensional structure brings strong dielectric and quantum confinement effects, so that the material has a large exciton binding energy and a suitable band gap, which provides suitable conditions for blue light emission, and the funnel-shaped energy transfer method also reduces the invalid loss of energy.

[0058] Based on this, the present application provides a kind of multi-tooth organic ligand modified perovskite light-emitting material and preparation method thereof, the structural characteristics of perovskite is formed by divalent lead ion, Cs + And halogen ion perovskite octahedral cell, and form multi-layer lead-based perovskite layer in angle sharing mode, the lead-based perovskite layer is separated into different thickness by organic ammonium cation, and forms organic-inorganic perovskite low-dimensional structure.

[0059] This invention also uses organic amide oxime compounds as multidentate organic ligands and passivators to modify the surface of lead-based perovskite layers, passivating surface defects and constructing a multiphase mixed quasi-two-dimensional lead-based perovskite system. The addition of organic amide oxime compounds plays a significant role in improving the morphology and properties of the perovskite film, resulting in a smooth film morphology, low defect state density, and improved PLQY of the modified perovskite luminescent material. The chemical composition and preparation method of the multidentate organic ligand-modified perovskite luminescent material of this invention are simple and easy to operate; therefore, this luminescent material and the involved multidentate organic ligands have good research and commercial value.

[0060] This invention uses lead-based perovskite as the research object, which can better induce the formation of perovskite octahedral cells and further form lead-based perovskite layers in a corner-sharing manner. The expression for the perovskite luminescent material modified with multidentate organic ligands in this invention is (L). z PEA y EA 2−y (CsPbX3) n−1 PbX4, where L is an organic amide oxime compound; PEA + It is a phenylethylammonium cation; EA + is ethylammonium cation; X is halogen; n is the number of perovskite octahedral layers between adjacent organic ammonium cation layers.

[0061] The perovskite luminescent material modified with multidentate organic ligands of the present invention has advantages such as low defect state density, good film morphology and phase arrangement, and high fluorescence quantum yield. The specific preparation methods of the multidentate organic ligands and the multidentate organic ligand-modified perovskite luminescent material are described in detail below.

[0062] The multidentate organic ligand has any one of the following structural formulas: R is selected from at least one of hydrogen, fluorine, chlorine, iodine and methyl.

[0063] In this invention, the benzene ring on the multidentate organic ligand can be replaced with a heterocycle such as a thiophene group. R represents a substituent on the benzene ring, and the substitution sites include ortho, meta, and para positions.

[0064] Preferably, the multidentate organic ligand is the following compound: HBMA or compound 3FHBMA: .

[0065] The synthesis method of compound HBMA is as follows: Dissolve 0.5 mol of benzonitrile and triethylamine in ethanol according to a molar ratio of 1:1.5, after stirring the mixture in a nitrogen atmosphere, gradually add a 50wt% hydroxylamine aqueous solution according to a molar ratio of benzonitrile to hydroxylamine of 1:1.5. Stir the reaction mixture at 85°C for 4 hours. After cooling to room temperature, concentrate under vacuum. Purify using silica gel column chromatography, elution solvent is petroleum ether and ethyl acetate according to a gradient elution of 20:1 to 2:1; obtain white powdery benzamide oxime.

[0066] The synthesis method of compound 3FHBMA is as follows: Dissolve 0.5 mol of 3,4,5-trifluorobenzonitrile and triethylamine in ethanol according to a molar ratio of 1:1.5, after stirring the mixture in a nitrogen atmosphere, gradually add a 50wt% hydroxylamine aqueous solution according to a molar ratio of 3,4,5-trifluorobenzonitrile to hydroxylamine of 1:1.5. Stir the reaction mixture at 85°C for 4 hours. After cooling to room temperature, concentrate under vacuum. Purify using silica gel column chromatography, elution solvent is petroleum ether and ethyl acetate according to a gradient elution of 20:1 to 5:1; obtain white powdery 3,4,5-trifluorobenzamide oxime.

[0067] The preparation method of the perovskite light-emitting material modified by the multidentate organic ligand comprises the following steps: S1, taking PbX2, CsX, EAX, PEAX and an organic amide oxime compound as precursor drugs, weighing the precursor drugs according to a molar ratio of PbX2, CsX, EAX, PEAX and the organic amide oxime compound of 1:0.9-1.1:0.55:0.5:0.01-0.1, dissolving the precursor drugs in a certain amount of organic solvent, stirring at room temperature in an inert atmosphere for 3-8 hours until the powder is completely dissolved, then filtering the solution with a filter head to obtain a precursor solution. The solvent used for dissolving the precursor drugs is N,N-dimethylformamide and / or dimethyl sulfoxide. The mass concentration of the precursor drugs in the precursor solution is 51.06-89.12 mg / mL. The concentration of the multidentate organic ligand in the precursor solution is 0.7-12 mmol / L.

[0068] S2, after filtering the precursor solution in step S1, use a pipette to take 100-200 microliters of the precursor solution and drop it on a clean and ozone-treated glass or ITO glass, spin-coat the precursor solution into a thin film on a spin coater. The rotation speed during spinning is 3000-5000 rpm for 30-120 seconds.

[0069] S3, the spin-coated substrate is moved to a heating table for annealing treatment; wherein the annealing temperature is 60-150 DEG C, and the annealing time is 0.5-20 min. Preferably, the annealing temperature is 130 DEG C, and the annealing time is 1 min. After the annealing, the substrate is cooled down, and a uniform thin film is obtained on the substrate, which is the perovskite light-emitting material modified by the polydentate organic ligand.

[0070] The perovskite light-emitting material modified by the polydentate organic ligand emits bright light in the sky blue region under the irradiation of ultraviolet light. According to the doping concentration of the organic amide oxime compound and the overall concentration of the precursor solution, the emission wavelength can be adjusted in the range of 476-495 nm.

[0071] The perovskite light-emitting material modified by the polydentate organic ligand of the present application is applied to the preparation of a device containing a quasi-two-dimensional lead-based perovskite structure with multi-phase mixing. The device is a photoluminescence device, an electroluminescence device or a solar cell device.

[0072] The internal quantum efficiency of the sky blue film with a wavelength of 485 nm prepared under the preferred annealing temperature and time can reach 68.16%. The perovskite light-emitting material modified by the polydentate organic ligand of the present application is used to prepare an electroluminescence device according to ITO / modified PEDOT:PSS / perovskite / PO-T2T / LiF / Al, and the external quantum efficiency of the emission wavelength of 490 nm in the electroluminescence device can reach 15.05%, and the brightness is as high as 2913 cd / m 2 . The emission wavelength of the perovskite thin film prepared into a device will be shifted. The polydentate organic ligand involved in the present application also has the potential of defect passivation in three-dimensional perovskite and quantum dot perovskite, and is also related to the performance improvement of perovskite solar devices.

[0073] The technical solutions of the present application are further described below through specific examples.

[0074] In the following examples, the methods are conventional methods unless otherwise specified; and the reagents and materials are commercially available unless otherwise specified.

[0075] EABr represents ethylamine bromide as a small molecule organic spacer. PEABr represents phenethylamine bromide as a small molecule organic spacer. Benzamide oxime, denoted as HBMA, is used as an organic ligand and a passivation agent. Trifluorobenzamide oxime, denoted as 3FHBMA, is used as an organic ligand and a passivation agent.

[0076] In each of the following examples, the electroluminescent device is ITO / modified PEDOT:PSS / perovskite / PO-T2T / LiF / Al. Among them, ITO represents a transparent conductive glass substrate; modified PEDOT:PSS is a hole injection / transport layer; perovskite is a perovskite light-emitting layer; the perovskite light-emitting layer is a perovskite light-emitting material modified by a polydentate organic ligand of the application; PO-T2T is an electron transport layer, and the Chinese name of PO-T2T is 2,4,6-tris[3-(diphenylphosphoryl)phenyl]-1,3,5-triazine; LiF is an electron injection layer; and Al is a cathode.

[0077] Example 1 A method for preparing a perovskite light-emitting material modified by a polydentate organic ligand, comprising the following steps: EABr and phenethylamine bromide are used as small-molecule organic spacers, and HBMA is used as an organic ligand and a passivation agent. PbBr2, CsBr, EABr, PEABr, and benzamide oxime HBMA are used as precursor chemicals. First, 100 μmol of PbBr2, 90 μmol of CsBr, 55 μmol of EABr, 50 μmol of PEABr, and 5.0 μmol of benzamide oxime HBMA are weighed into a serum bottle, followed by the addition of 1.25 mL of dimethyl sulfoxide as a solution, and a polytetrafluoroethylene magnet is added for thorough stirring in a nitrogen-filled glove box. After about 4 hours of stirring, the solution is filtered to remove insoluble impurities to obtain a precursor solution. The mass concentration of the precursor chemicals in the precursor solution is 58.848 mg / mL. The concentration of benzamide oxime HBMA in the precursor solution is 4 mmol / L.

[0078] About 120 microliters of the precursor solution are taken with a pipette and dropped onto a cleaned and ozone-treated substrate, which is an ITO glass sheet. The substrate is spin-coated at a speed of 4000 rpm for 60 seconds, and then the spin-coated substrate is moved to an annealing table for annealing at a temperature of 130°C for 1 min to obtain a blue perovskite light-emitting film, which is a perovskite light-emitting material modified by a polydentate organic ligand.

[0079] The molecular structure of the benzamide oxime used in Example 1 is shown in Figure 1 .

[0080] The absorption spectrum of the blue perovskite light-emitting film prepared in Example 1 is shown in Figure 2 . The Figure 2As can be seen, the blue perovskite luminescent film prepared in Example 1 has absorption peaks corresponding to different phases at different wavelengths. The four absorption peaks at 400nm, 424nm, 451nm and 467nm correspond to the n=1, n=2, n=3 and n≥4 phases of the perovskite luminescent material modified with multidentate organic ligands, respectively, which reflects the quasi-two-dimensional characteristics.

[0081] The photoluminescence spectrum of the blue perovskite luminescent thin film prepared in Example 1 is as follows: Figure 3 As shown. By Figure 3 As can be seen, there is a strong emission peak at 485nm, with a full width at half maximum (FWHM) of 27nm.

[0082] The fluorescence quantum yield spectrum of the blue perovskite luminescent thin film prepared in Example 1 is as follows: Figure 4 As shown, the photoluminescence quantum yield is 68.16% by integration.

[0083] The perovskite luminescent film prepared without HBMA was used as a standard control film, denoted as control. The scanning electron microscope (SEM) images of the blue perovskite luminescent film with HBMA added in Example 1, compared with the standard control film without HBMA, are shown below. Figure 5 .Depend on Figure 5 As can be seen, the preparation method of the perovskite luminescent material modified by the multidentate organic ligand in Example 1 of the present invention can obtain a smoother and flatter blue perovskite luminescent film without deep grooves or obvious pinholes, thereby helping to improve the stability and external quantum efficiency of electroluminescent devices.

[0084] An electroluminescent device prepared using a perovskite luminescent thin film without HBMA was used as a standard control device and denoted as Pristine. A schematic diagram of the EQE of the blue perovskite luminescent thin film prepared in Example 1 in the electroluminescent device is shown below. Figure 6 As shown, EQE represents the external quantum efficiency. Compared with the standard control device without HBMA, the external quantum efficiency of the electroluminescent device with 4 mmol / L HBMA in Example 1 was significantly improved. The maximum external quantum efficiency of the electroluminescent device prepared by the blue perovskite light-emitting thin film in Example 1 increased from 7.33% of the standard control device to 15.05%.

[0085] An electroluminescent device prepared using a perovskite luminescent thin film without HBMA was used as a standard control device and denoted as Pristine. The operating time diagram of the blue perovskite luminescent thin film prepared in Example 1 in the electroluminescent device is shown below. Figure 7As shown, L / L0 represents the ratio of real-time luminance to initial luminance. Compared with the standard control device without adding HBMA, the service life of the electroluminescent device of Example 1 with 4 mmol / L of HBMA is obviously improved, and the lifetime half-life period of the electroluminescent device prepared by the blue light perovskite luminescent film of Example 1 is increased from 3.04 min of the standard control device to 5.53 min. Thus, it is shown that the stability of the electroluminescent device prepared by the blue light perovskite luminescent film of Example 1 of the present application is relatively good.

[0086] Example 2 A preparation method of a perovskite luminescent material modified by a multi-dentate organic ligand, comprising the following steps: EABr and phenethylamine bromide are used as small molecule organic spacers, and HBMA is used as an organic ligand and a passivation agent. PbBr2, CsBr, EABr, PEABr and benzamide oxime HBMA are used as precursor drugs. First, 100 μmol of PbBr2, 90 μmol of CsBr, 55 μmol of EABr, 50 μmol of PEABr and 5.0 μmol of benzamide oxime HBMA are weighed and placed in a serum bottle, then 1.0 mL of dimethyl sulfoxide is added as a solution, a polytetrafluoroethylene magnet is added, and stirring is performed in a nitrogen-filled glove box. After about 4 hours of stirring, the solution is filtered to remove insoluble impurities, and a precursor solution is obtained. The mass concentration of the precursor drugs in the precursor solution is 73.56 mg / mL. The concentration of benzamide oxime HBMA in the precursor solution is 5 mmol / L.

[0087] About 120 microliters of the precursor solution are taken by a pipette and dropped on a cleaned and ozone-treated substrate, which is a glass sheet. The substrate is spin-coated at a speed of 4000 rpm for 60 seconds, and then the spin-coated substrate is moved to an annealing table for annealing at a temperature of 130°C for 1 min. A blue light perovskite luminescent film is obtained, which is a perovskite luminescent material modified by a multi-dentate organic ligand.

[0088] The photoluminescence spectrum of the blue light perovskite luminescent film prepared in Example 2 is shown in FIG. 2. Figure 8 As shown, there is a strong emission peak at 487 nm, and the half-peak width is 28 nm.

[0089] The perovskite luminescent film without adding HBMA is used as a standard control film, which is denoted as control. The scanning electron microscope spectrum of the blue light perovskite luminescent film of Example 2 with HBMA compared with the standard control film without adding HBMA is shown in FIG. 3. Figure 9 Figure 9 ​It can be seen that the preparation method of the perovskite light-emitting material modified by the multi-dentate organic ligand in the embodiment 2 of the present application can obtain a more flat blue light perovskite light-emitting film surface, without deep gullies, and without obvious pinholes.

[0090] The electroluminescent device prepared by the perovskite light-emitting film without adding HBMA is taken as a standard control device, denoted as Pristine. The EQE of the blue light perovskite light-emitting film prepared in the embodiment 2 in the electroluminescent device is schematically shown in Figure 10 Compared with the standard control device, the external quantum efficiency of the electroluminescent device in the embodiment 2 with 5 mmol / L HBMA is obviously improved.

[0091] Embodiment 3 A preparation method of a perovskite light-emitting material modified by a multi-dentate organic ligand, comprising the following steps: EABr and phenethylamine bromide are taken as small molecule organic spacers, and 3FHBMA is taken as an organic ligand and a passivation agent. PbBr2, CsBr, EABr, PEABr and trifluorobenzamide oxime 3FHBMA are taken as precursor drugs. Firstly, 100 μmol of PbBr2, 90 μmol of CsBr, 55 μmol of EABr, 50 μmol of PEABr and 5 μmol of trifluorobenzamide oxime 3FHBMA are weighed and placed in a serum bottle, then 1.25 mL of dimethyl sulfoxide is added as a solution, a polytetrafluoroethylene magnet is added, and stirring is performed in a nitrogen-filled glove box. After about 4 hours of stirring, the solution is filtered to remove insoluble impurities to obtain a precursor solution. The mass concentration of the precursor drugs in the precursor solution is 59.064 mg / mL. The concentration of trifluorobenzamide oxime 3FHBMA in the precursor solution is 4 mmol / L.

[0092] About 120 microliters of the precursor solution is sucked by a pipette and dropped on a cleaned and ozone-treated substrate, which is an ITO glass sheet. The substrate is spin-coated at a rotation speed of 4000 rpm for 60 seconds, and then the spin-coated substrate is moved to an annealing table for annealing at a temperature of 130°C for 1 min, to obtain a corresponding blue light perovskite light-emitting film, which is a perovskite light-emitting material modified by a multi-dentate organic ligand.

[0093] The molecular structural formula of the trifluorobenzamide oxime compound 3FHBMA used in the embodiment 3 is shown in Figure 11 .

[0094] The emission spectrum of the blue light perovskite light-emitting film prepared in the embodiment 3 is shown in Figure 12 , and there is a relatively strong emission peak at 486 nm, with a half-peak width of 28 nm.

[0095] The perovskite luminescent film without 3FHBMA was used as a standard control film, denoted as control. The scanning electron microscope (SEM) images of the blue perovskite luminescent film with 3FHBMA in Example 3, compared with the standard control film without 3FHBMA, are shown below. Figure 13 As shown. By Figure 13 As can be seen, the preparation method of the perovskite luminescent material modified by the multidentate organic ligand in Example 3 of the present invention can obtain a blue perovskite luminescent film with a smaller roughness, and the grooves on the surface of the blue perovskite luminescent film in Example 3 are significantly reduced.

[0096] An electroluminescent device prepared without 3FHBMA was used as a standard control device and denoted as Pristine. A schematic diagram of the EQE of the blue perovskite luminescent film prepared in Example 3 in the electroluminescent device is shown below. Figure 14 As shown, compared with the standard control device, the external quantum efficiency of the device with 4 mmol / L 3FHBMA added in Example 3 was significantly improved.

[0097] Example 4 A method for preparing a perovskite luminescent material modified with a multidentate organic ligand includes the following steps: EABr and phenethylamine bromide were used as small-molecule organic spacers, and HBMA was used as an organic ligand and passivating agent. PbBr2, CsBr, EABr, PEABr, and benzamide oxime HBMA were used as precursors. First, 100 μmol of PbBr2, 90 μmol of CsBr, 55 μmol of EABr, 50 μmol of PEABr, and 10 μmol of benzamide oxime HBMA were weighed and placed in a serum bottle. Then, 0.83 mL of dimethyl sulfoxide was added as a solution. A polytetrafluoroethylene magnet was added, and the mixture was stirred thoroughly in a nitrogen-filled glove box. After stirring for approximately 4 hours, the solution was filtered to remove insoluble impurities, yielding the precursor solution. The mass concentration of the precursor drugs in the precursor solution was 88.71 mg / mL. The concentration of benzamide oxime HBMA in the precursor solution was 12 mmol / L.

[0098] Approximately 120 μL of precursor solution was pipetted onto a clean, ozone-treated glass substrate. The substrate was spin-coated at 4000 rpm for 60 seconds. The spin-coated substrate was then transferred to an annealing stage and annealed at 130°C for 1 minute to obtain a blue perovskite luminescent film, which is a perovskite luminescent material modified with multidentate organic ligands.

[0099] The perovskite light-emitting thin film prepared without adding HBMA is taken as a standard control thin film, recorded as control. The scanning electron microscope images of the blue perovskite light-emitting thin film of Example 4 with HBMA and the standard control thin film without HBMA show that the blue perovskite light-emitting thin film of Example 4 with HBMA is relatively smoother and more flat, without deep gullies and obvious pinholes.

[0100] The electroluminescent device prepared from the perovskite light-emitting thin film without adding HBMA is taken as a standard control device, recorded as control. Compared with the standard control device, the external quantum efficiency of the blue perovskite light-emitting thin film of Example 4 with 12 mmol / L HBMA in the electroluminescent device is obviously improved.

[0101] In summary, the perovskite light-emitting material modified by the polydentate organic ligand is prepared by the polydentate organic ligand modification in the embodiments of the present application, the core of which is the application of a new type of polydentate organic ligand / passivator. The blue perovskite light-emitting thin film prepared after adding the ligand has a more flat film morphology and a more reasonable phase distribution, and more importantly, the blue thin film modified by the organic ligand HBMA or 3FHBMA not only has extremely high brightness in the light-emitting device, but also exhibits obviously improved external quantum efficiency and device stability.

[0102] The above merely describes preferred embodiments of the present application but should not be used to restrict the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A perovskite luminescent material modified with a multidentate organic ligand, characterized in that, It is divalent lead ions, Cs + The perovskite octahedral cells formed by halide ions form multiple lead-based perovskite layers through corner sharing. The lead-based perovskite layers are separated by organic ammonium cation layers. Organic amide oxime compounds are used as multidentate organic ligands and passivators to modify the surface of the lead-based perovskite layers, passivating surface defects and constructing a multiphase mixed quasi-two-dimensional lead-based perovskite system, thus obtaining perovskite luminescent materials modified by multidentate organic ligands.

2. The perovskite luminescent material modified with multidentate organic ligands according to claim 1, characterized in that, The organic amide oxime compounds have any one of the following structural formulas: ； R is selected from at least one of hydrogen, fluorine, chlorine, iodine and methyl.

3. The perovskite luminescent material modified with multidentate organic ligands according to claim 2, characterized in that, The polydentate organic ligand is either compound HBMA or compound 3FHBMA, as shown below: 。 4. The perovskite luminescent material modified with multidentate organic ligands according to claim 1, characterized in that, The organic ammonium cation layer is a mixture of phenylethylammonium cations and ethylammonium cations; The lead-based perovskite layer inorganic layer is composed of Cs + Pb 2+ and X - An octahedral unit cell array composed of ions, where X is a halide ion and the halide ion is Br. - Cl - and I - At least one of them.

5. A method for preparing a perovskite luminescent material modified with a multidentate organic ligand according to any one of claims 1 to 4, characterized in that, Includes the following steps: Under an inert atmosphere, PbX2, CsX, EAX, PEAX and organic amide oxime compounds were stirred and mixed with an organic solvent, and then filtered to obtain a precursor solution. The precursor liquid was spin-coated onto a substrate to prepare a precursor film on the substrate; the substrate with the precursor film was then annealed to obtain a perovskite luminescent material modified with multidentate organic ligands.

6. The method for preparing the perovskite luminescent material modified with multidentate organic ligands according to claim 5, characterized in that, The molar ratio of PbX2, CsX, EAX, PEAX and organic amide oxime compounds is 1:0.9–1.1:0.55:0.5:0.01–0.1; the concentration of the polydentate organic ligand in the precursor solution is 0.7 mmol / L–12 mmol / L.

7. The method for preparing the perovskite luminescent material modified with multidentate organic ligands according to claim 5, characterized in that, The annealing temperature is 60℃~150℃, and the annealing time is 0.5min~20min.

8. The method for preparing the perovskite luminescent material modified with multidentate organic ligands according to claim 5, characterized in that, The organic solvent is N,N-dimethylformamide and / or dimethyl sulfoxide; the spin coating speed is 3000 rpm to 5000 rpm, and the spin coating time is 30 s to 120 s.

9. The use of the perovskite luminescent material modified with a multidentate organic ligand according to any one of claims 1 to 4 in the fabrication of devices containing a quasi-two-dimensional lead-based perovskite structure with multiphase mixing.

10. The application of the multidentate organic ligand-modified perovskite luminescent material according to claim 9 in the fabrication of devices containing a multiphase mixed quasi-two-dimensional lead-based perovskite structure, characterized in that, The device is a photoluminescent device, an electroluminescent device, or a solar cell device.

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