Perovskite nanocrystalline film and preparation method and application thereof
By performing a directional dissolution-recrystallization process in chlorobenzene solution and using phosphine oxides to cover perovskite nanocrystals, the problem of increasing the fluorescence quantum yield of perovskite layers in existing technologies has been solved, and efficient perovskite nanocrystallization film preparation has been achieved, thereby improving photoelectric performance.
Patent Information
- Application Number
- CN202511331979.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-18
- Publication Date
- 2025-12-30
AI Technical Summary
Existing technologies require two separate processes: nanostructure synthesis and defect passivation. This complicates the improvement of fluorescence quantum yield in perovskite layers and increases costs, making it difficult to achieve efficient improvement of fluorescence quantum yield in perovskite layers.
By performing a directional dissolution-recrystallization process in chlorobenzene solution, phosphine oxides are used to cover perovskite nanocrystal particles, achieving in-situ nanocrystalization of polycrystalline thin films. Combined with the passivation effect of phosphine oxide groups, highly efficient perovskite nanocrystalized thin films are prepared.
This simplifies the fabrication process of perovskite devices, significantly improves the photoluminescence intensity of polycrystalline thin films and the brightness of electroluminescent devices, and realizes the high-efficiency luminescence performance of perovskite materials.
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Figure CN121240751A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of perovskite light-emitting device fabrication technology, specifically relating to a perovskite nanocrystalline thin film, its preparation method, and its application. Background Technology
[0002] Organic-inorganic hybrid metal halide perovskites, with their high luminous efficiency, excellent defect tolerance, and superior color purity, have become key semiconductor materials in the field of optoelectronic devices. The commercial application of these materials urgently requires solving the core problem of improving the fluorescence quantum yield of perovskite layers—high quantum yield directly determines radiative recombination efficiency and carrier utilization, and has a decisive impact on the performance of devices such as light-emitting diodes and photodetectors. Current mainstream improvement strategies include surface passivation to suppress nonradiative recombination, quantum confinement effect modulation, solvent engineering to optimize crystallization, and composition design, among which surface passivation and confinement effects are particularly crucial.
[0003] Phosphine oxide derivatives (PODs), as multifunctional surface modifiers, simultaneously function as surface passivators and nanocrystalline ligands in the perovskite field. The strongly polar phosphoxy group can form stable bonds with uncoordinated lead atoms on the perovskite surface, efficiently passivating deep-level defects and modulating charge transport behavior, even raising the quasi-Fermi level splitting value to over 90% of the theoretical limit. Meanwhile, PODs serve as key ligands in the synthesis of perovskite quantum dots and nanocrystals, providing crucial support for the fabrication of high-performance devices. However, current technologies require separate implementation of nanostructure synthesis and defect passivation processes, leading to increased complexity and cost in device fabrication. Developing efficient and simple radiation recombination enhancement methods has become a core requirement for promoting the commercialization of metal halide perovskites. Summary of the Invention
[0004] In view of this, the technical problem to be solved by the present invention is to provide a perovskite nanocrystalline thin film, its preparation method, and its application. The nanocrystalline thin film provided by the present invention has high luminous efficiency and innovatively integrates the dual functions of phosphine oxides. In-situ nanocrystallization of polycrystalline thin films is achieved through a directional dissolution-recrystallization process in chlorobenzene solution, which can be used to prepare high-efficiency electroluminescent devices.
[0005] According to one aspect of this application, a perovskite nanocrystallized film is provided, wherein the surface of the perovskite nanocrystallized film has perovskite nanocrystallized particles with a particle size of 10~1000nm.
[0006] The perovskite nanocrystalline film is covered with phosphine oxides;
[0007] The phosphine oxide is selected from trialkyl or aromatic substituted phosphine oxide molecules with the chemical formula R3PO;
[0008] Wherein, R is selected from C1~C 20 Alkyl or C6~C 30 One of the aromatic groups.
[0009] According to another aspect of this application, a method for preparing the above-mentioned perovskite nanocrystalline thin film is provided, comprising the following steps:
[0010] Under an inactive atmosphere, a phosphine oxide compound is mixed with a solvent and stirred overnight at room temperature to obtain a solvent solution containing the phosphine oxide compound. The solvent solution containing the phosphine oxide compound is then spin-coated onto the surface of a polycrystalline perovskite film, allowing the solvent to evaporate spontaneously during the spin-coating process, thereby obtaining the perovskite nanocrystalline film.
[0011] The solvent is selected from at least one of chlorobenzene, isopropanol, ethanol, or acetonitrile.
[0012] The concentration of the phosphine oxide in the solvent solution is 10~60 g / L.
[0013] Optionally, in the solvent solution containing the phosphine oxide, the concentration of the phosphine oxide is any value among 10 g / L, 20 g / L, 30 g / L, 40 g / L, 50 g / L, and 60 g / L, or a range between any two.
[0014] The polycrystalline perovskite thin film is obtained through the following steps:
[0015] Under an inactive atmosphere, an organic solvent, AX and PbX2 are mixed and stirred overnight at room temperature to obtain a mixture. The mixture is then coated onto the substrate surface and annealed to obtain the polycrystalline perovskite film.
[0016] Wherein, A is a monovalent cation selected from at least one of methylamine ion, formamidine ion, and cesium ion;
[0017] X is selected from at least one of the elements chlorine, bromine, and iodine;
[0018] The organic solvent is selected from dimethylformamide and / or dimethyl sulfoxide;
[0019] The concentration of PbX2 in the mixture is 0.1~1.5 mol / L, calculated as the molar amount of lead.
[0020] Optionally, the concentration of PbX2 in the mixture is any value among 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 1 mol / L, and 1.5 mol / L, or any range between two of them.
[0021] The ratio of the concentration of AX to the concentration of PbX2 in the mixture is 1:1 to 1.2.
[0022] Optionally, the ratio of the concentration of AX to the concentration of PbX2 in the mixture is any value among 1:1, 1:1.1, and 1:1.2, or any range between the two.
[0023] The substrate is selected from at least one of indium tin oxide conductive glass and fluorine-containing tin oxide conductive glass.
[0024] The annealing temperature is 100~150℃;
[0025] Optionally, the annealing temperature is any value among 100°C, 110°C, 120°C, 130°C, 140°C, and 150°C, or a range between any two.
[0026] The annealing time is 10~45 minutes.
[0027] Optionally, the annealing time is any value among 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, and 45 min, or a range between any two.
[0028] The inactive atmosphere is selected from at least one of nitrogen atmosphere, helium atmosphere, and argon atmosphere.
[0029] The coating is selected from spin coating or slot coating.
[0030] According to another aspect of this application, a perovskite light-emitting diode device is provided, comprising a positive electrode, a hole injection layer, a light-emitting layer, an electron transport layer, and a negative electrode sequentially combined.
[0031] The light-emitting layer contains the perovskite nanocrystal thin film described above or the perovskite nanocrystal thin film obtained by the above preparation method.
[0032] The perovskite nanocrystalline thin film of this application is formed by the in-situ spontaneous interaction between phosphine oxide molecules and polycrystalline perovskite thin films. Compared with existing technologies, this invention provides a simpler and easier method for preparing perovskite nanocrystalline thin films, avoiding the multi-step preparation schemes of traditional methods. This method combines the confinement effect of nanocrystals with the passivation effect of phosphine oxide groups in phosphine oxides, resulting in an exponential increase in the photoluminescence intensity of polycrystalline perovskite thin films and a several-fold enhancement in the luminescence intensity of nanocrystalline samples in electroluminescent devices. Our work provides a convenient and easy new method for developing high-brightness perovskite optoelectronic devices, contributing to the promotion and application of perovskite materials.
[0033] In this application, C1~C 20 C6~C 30 "etc." refers to the number of carbon atoms contained in the group.
[0034] In this application, the term "alkyl" refers to a group formed by the loss of any one hydrogen atom from an alkane molecule.
[0035] In this application, the term "aromatic group" refers to a group formed by the loss of a hydrogen atom from an aromatic ring in an aromatic compound molecule; for example, p-tolyl formed by the loss of a hydrogen atom at the para-position of the methyl group on the benzene ring of toluene.
[0036] The beneficial effects that this application can produce include:
[0037] 1. This application provides a novel surface-nanocrystalline perovskite thin film with excellent photoluminescence and electroluminescence properties.
[0038] 2. This application utilizes phosphine oxide molecules to spontaneously induce in-situ nanocrystallization in polycrystalline perovskite films, thereby enhancing the photoelectric properties of metal halide perovskite polycrystalline films. This significantly improves the luminescence performance of perovskite polycrystalline films, far exceeding that of ordinary modification methods.
[0039] 3. The method for preparing perovskite nanocrystalline thin films provided in this application has fewer steps than traditional processes and does not require ligand replacement, making it more suitable for mainstream solution-based perovskite preparation processes.
[0040] 4. The perovskite LED device prepared by the method described in this application exhibits a brightness several times higher than the control group. Our work provides a convenient and easy-to-implement new method for developing high-brightness perovskite optoelectronic devices, contributing to the promotion and application of perovskite materials. Attached Figure Description
[0041] Figure 1 The photoluminescence and fluorescence spectra of the target thin film obtained in Example 1 before and after treatment with phosphine oxides are shown.
[0042] Figure 2 The images show the scanning electron microscope (SEM) results of the target thin film obtained in Example 1 before and after treatment with phosphine oxides, where a is the control sample and b is the modified sample.
[0043] Figure 3 The photoluminescence and fluorescence spectra of the target thin film obtained in Example 2 before and after treatment with phosphine oxides are shown.
[0044] Figure 4 The images show the scanning electron microscope (SEM) results of the target thin film obtained in Example 2 before and after treatment with phosphine oxides, where a is the control sample and b is the modified sample.
[0045] Figure 5 The photoluminescence and fluorescence spectra of the target thin film obtained in Example 3 before and after treatment with phosphine oxides are shown.
[0046] Figure 6The images show the scanning electron microscope (SEM) results of the target thin film obtained in Example 3 before and after treatment with phosphine oxides, where a is the control sample and b is the modified sample.
[0047] Figure 7 The LED device performance test results of the nanocrystalline perovskite thin film provided in Example 1 are shown in Figure a, where a is a comparison of brightness curves and b is a comparison of external quantum efficiency curves. Detailed Implementation
[0048] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0049] The steady-state photoluminescence spectrometer (PL) used in this application was an Edinburgh Instruments FLS920 fluorescence spectrometer, measured at room temperature, with a measurement range of 500–860 nm, and an excitation source of a 406 nm laser.
[0050] Example 1
[0051] Nanocrystallization of polycrystalline methylamine lead-iodide perovskite films: Under an inert atmosphere, methylamine hydroiodate and lead iodide powder were dissolved in a solvent at a feed ratio of 1:1 (0.6 mol / L: 0.6 mol / L). The solvent was prepared by mixing dimethyl sulfoxide and dimethylformamide in a 1:4 ratio (200 μL: 800 μL), with a lead ion concentration of 0.6 mol / L. The solution was stirred overnight at room temperature under a nitrogen atmosphere. Trioctylphosphine oxide molecules were dissolved in chlorobenzene at a concentration of 30 mg / mL under a nitrogen atmosphere and stirred overnight at room temperature. Before use, all solutions were first filtered through a 0.22 μm pore size polytetrafluoroethylene filter, and then transferred to a clean substrate for spin-coating. The three-dimensional perovskite spin coating process consists of two stages: the first stage is 1000 rpm for 10 s, and the second stage is 6000 rpm for 30 s. Five s before the end of the spin coating, 120 μL of chlorobenzene (CB) is used as an anti-solvent. Finally, the sample is transferred to a 100℃ hot stage and annealed for 10 min to obtain the perovskite film.
[0052] The trioctylphosphine oxide solution prepared under nitrogen atmosphere was dropped onto the surface of the perovskite film using a pipette and then spin-coated at a spin speed of 4000 rpm.
[0053] Figure 1 The photoluminescence and fluorescence spectra of the target thin film obtained in Example 1 before and after treatment with phosphine oxides are shown. It can be seen that the fluorescence intensity of the modified perovskite thin film is dramatically enhanced.
[0054] Figure 2The images show the scanning electron microscopy (SEM) results of the target thin film obtained in Example 1 before and after treatment with phosphine oxides. This indicates that the perovskite thin film is transformed into a perovskite nanocrystalline structure after modification.
[0055] The substrate is indium tin oxide conductive glass, and all of them are ultrasonically cleaned before use. The cleaning solution and the order of cleaning are: ethanol, isopropanol, ethanol, and each cleaning time is 40 minutes.
[0056] LED device fabrication: First, clean the ITO substrate as described above, then use a pipette to transfer NiO into the air. X Aqueous solutions were spin-coated onto the ITO substrate at 4000 rpm for 50 seconds, then transferred to a 150°C hot plate for annealing for 15 minutes. Subsequently, a 0.5 mg / mL solution of 4-(9H-carbazole-9-yl)butylphosphonic acid (4-PACZ) in ethanol was applied to the annealed NiO substrate using a pipette. X Spin-coating was performed on the film at 4000 rpm for 30 s. The sample was then transferred to a nitrogen-atmosphere glove box, and a 4 mg / m³ LTF chlorobenzene solution was spin-coated onto the surface of the 4 PACZ film. Annealing was then carried out at 105 °C for 15 min. The annealing was performed at a pressure <3.0 × 10⁻⁶ ppm. −4 A 1.2 nm thick LiF layer was deposited under Pa conditions, followed by the fabrication of a perovskite layer in a glove box using the process described above. After the perovskite layer was prepared, another deposition process was performed, also under a pressure <3.0 × 10⁻⁶ Pa. −4 POT2T (40 nm), LiF (1 nm), and Al (100 nm) were deposited under Pa conditions. In the electroluminescence spectrum, the LED device made of nanocrystalline perovskite film under the same applied voltage conditions had an electroluminescence intensity more than three times that of the control group sample.
[0057] Figure 7 The LED device performance test results are for the nanocrystalline perovskite thin film provided in Example 1. Figure 7 In the tests, the nanocrystalline sample achieved a maximum brightness of 2961 cdm⁻², while the untreated control group LED device only achieved a maximum brightness of 890 cdm⁻². In the external quantum efficiency (EQE) test, the nanocrystalline sample achieved a maximum EQE of 21.6%, compared to only 14.6% for the control group. These experimental data demonstrate that the strategy of nanocrystallizing polycrystalline perovskite films using organophosphorus oxide derivative molecules to enhance their photoelectric properties not only improves the photoluminescence of polycrystalline perovskite materials but also significantly enhances their electroluminescence.
[0058] Example 2
[0059] Nanocrystallization of polycrystalline methylamine lead bromide perovskite films: Under a nitrogen atmosphere, methylamine hydrobromide and lead bromide powder were dissolved in a solvent at a feed ratio of 1:1 (0.6 mol / L: 0.6 mol / L). The solvent was prepared by mixing dimethyl sulfoxide and dimethylformamide in a 1:4 ratio (200 μL: 800 μL), with a lead ion concentration of 0.6 mol / L. The solution was stirred overnight at room temperature under a nitrogen atmosphere. Trioctylphosphine oxide molecules were dissolved in chlorobenzene at a concentration of 30 mg / mL under an inactive nitrogen atmosphere and stirred overnight at room temperature. Before use, all solutions were first filtered through a 0.22 μm pore size polytetrafluoroethylene filter and then transferred to a clean substrate (ITO / FTO) for spin-coating. The three-dimensional perovskite spin coating process consists of two stages: the first stage is 1000 rpm for 10 s, and the second stage is 6000 rpm for 30 s. Five s before the end of the spin coating, 120 μL of chlorobenzene (CB) is used as an anti-solvent. Finally, the sample is transferred to a 100℃ hot stage and annealed for 10 min.
[0060] The trioctylphosphine oxide solution prepared under nitrogen atmosphere was dropped onto the surface of the perovskite film using a pipette and then spin-coated at a spin speed of 4000 rpm.
[0061] Figure 3 The photoluminescence and fluorescence spectra of the target film obtained in Example 2 before and after treatment with phosphine oxides are shown. It can be seen that the fluorescence intensity of the modified perovskite film is dramatically enhanced.
[0062] Figure 4 The images show the scanning electron microscopy (SEM) results of the target thin film obtained in Example 2 before and after treatment with phosphine oxides. This indicates that the perovskite thin film is transformed into a perovskite nanocrystalline structure after modification.
[0063] The substrate is indium tin oxide conductive glass, and all of them are ultrasonically cleaned before use. The cleaning solution and the order of cleaning are: ethanol, isopropanol, ethanol, and each cleaning time is 40 minutes.
[0064] Example 3
[0065] Nanocrystallization of formamidinium lead-iodide perovskite polycrystalline thin films: Under a nitrogen atmosphere, formamidinium hydroiodate and lead iodide powder were dissolved in a solvent at a feed ratio of 1:1 (0.6 mol / L: 0.6 mol / L). The solvent was prepared by mixing dimethyl sulfoxide and dimethylformamide in a 1:4 ratio (200 μL: 800 μL), with a lead ion concentration of 0.6 mol / L. The solution was stirred overnight at room temperature under a nitrogen atmosphere. Trioctylphosphine oxide molecules were dissolved in chlorobenzene at a concentration of 30 mg / mL under an inactive atmosphere and stirred overnight at room temperature. Before use, all solutions were first filtered through a 0.22 μm pore size polytetrafluoroethylene filter and then transferred to a clean substrate for spin-coating. The three-dimensional perovskite spin coating process consists of two stages: the first stage is 1000 rpm for 10 s, and the second stage is 6000 rpm for 30 s. Five s before the end of the spin coating, 120 μL of chlorobenzene (CB) is used as an anti-solvent. Finally, the sample is transferred to a 100℃ hot stage and annealed for 10 min.
[0066] The trioctylphosphine oxide solution prepared under nitrogen atmosphere was dropped onto the surface of the perovskite film using a pipette and then spin-coated at a spin speed of 4000 rpm.
[0067] Figure 5 The photoluminescence and fluorescence spectra of the target film obtained in Example 3 before and after treatment with phosphine oxides are shown. It can be seen that the fluorescence intensity of the modified perovskite film is dramatically enhanced.
[0068] Figure 6 The images show the scanning electron microscopy (SEM) results of the target thin film obtained in Example 3 before and after treatment with phosphine oxides. They indicate that the perovskite thin film is transformed into a perovskite nanocrystalline structure after modification.
[0069] The substrate is indium tin oxide conductive glass, and all of them are ultrasonically cleaned before use. The cleaning solution and the order of cleaning are: ethanol, isopropanol, ethanol, and each cleaning time is 40 minutes.
[0070] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions made by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A perovskite nanocrystallized film, characterized in that, the perovskite nanocrystallized film has perovskite nanocrystalline particles with a particle size of 10-1000 nm on the surface; the perovskite nanocrystalline film is covered by a phosphine oxide compound; the phosphine oxide compound is selected from a trialkyl or aromatic group-substituted phosphine oxide compound molecule with a chemical formula of R 3 PO; wherein R is selected from one of C1-C4 alkyl or C6-C10 aryl. 20 30 alkyl or C6-C10 aryl. 2.A preparation method of the perovskite nanocrystallized film according to claim 1, characterized in that, the method comprises the following steps: a solvent solution containing a phosphine oxide compound is spin-coated onto the surface of a polycrystalline perovskite film under an inert atmosphere, and the solvent is volatilized to obtain the perovskite nanocrystallized film. 3.The preparation method according to claim 2, characterized in that, the solvent is selected from at least one of chlorobenzene, isopropanol, ethanol or acetonitrile. 4.The preparation method according to claim 2, characterized in that, the concentration of the phosphine oxide compound in the solvent solution containing the phosphine oxide compound is 10-60 g / L. 5.The preparation method according to claim 2, characterized in that, the polycrystalline perovskite film is obtained by the following steps: an organic solvent, AX and PbX 2 are mixed under an inert atmosphere, and the mixture is stirred overnight at room temperature to obtain a mixed solution, the mixed solution is coated on the surface of a substrate, and annealing is performed to obtain the polycrystalline perovskite film; wherein A is a monovalent cation selected from at least one of methylamine ion, formamidinium ion and cesium ion; X is selected from at least one of chlorine element, bromine element and iodine element; the organic solvent is selected from dimethylformamide and / or dimethyl sulfoxide; the concentration of PbX 2 in the mixed solution is 0.1-1.5 mol / L, calculated based on the molar amount of lead element; the ratio of the concentration of AX to the concentration of PbX 2 in the mixed solution is 1:1-1.
2. 6.The preparation method according to claim 5, characterized in that, the substrate is selected from at least one of indium tin oxide conductive glass and fluorine-containing tin oxide conductive glass. 7.The preparation method according to claim 5, characterized in that, the annealing temperature is 100-150 ℃; the annealing time is 10-45 min. 8.The preparation method according to claim 5, characterized in that, the inert atmosphere is selected from at least one of nitrogen atmosphere, helium atmosphere and argon atmosphere. 9.The preparation method according to claim 5, characterized in that, the coating is selected from spin coating or slot coating. 10.A perovskite light-emitting diode device, characterized in that, it comprises, in sequence, an anode, a hole injection layer, a light-emitting layer, an electron transport layer and a cathode; the light-emitting layer contains the perovskite nanocrystallized film according to claim 1 or the perovskite nanocrystallized film obtained by the preparation method according to any one of claims 2-9.