A method for preparing perovskite nanocrystal luminescent material

Abstract

The invention discloses a method for preparing a perovskite nanocrystal luminescent material, which adopts a step-by-step preparation method through a precursor, has good reaction controllability, does not require the addition of organic ligands, and does not require heating during the reaction process, and has the characteristics of simple preparation, low cost, and suitability for large-scale production. The obtained perovskite nanocrystal luminescent material has high quantum yield and good stability, and can be widely used in photoluminescent devices, lasers, and nonlinear optical devices.

Description

[0001] The present invention belongs to the technical field of luminescent materials, and in particular relates to a method for preparing a perovskite nanocrystalline luminescent material. Background Art

[0002] All-inorganic metal halide perovskite CsPbX 3 (X=Cl, Br, I) Nanocrystalline luminescent materials are widely used in display, lighting, solar cells and other fields due to their high quantum yield, high color purity, tunable spectrum and easy preparation.

[0003] In 2015, Professor Kovalenko's research group used the hot injection method to prepare CsPbX for the first time. 3 Nanocrystals can cover the entire visible light range, and the quantum efficiency in the colloidal state is as high as 50% to 90%. 3 (X=Cl, Br, I) nanocrystals, as the colloid turns into solid powder, the fluorescence is sharply quenched due to the shedding of surface ligands. In order to solve this problem, in 2017, Professor Sargent's research group converted CsPbBr 3 Embedded in Cs 4 PbB 6 , forming CsPbBr 3 / Cs 4 PbB 6 The quantum efficiency of this solid-state perovskite is as high as 90%. In 2020, Professor Li Yang's research group further improved the CsPbBr by optimizing solvents, adding ligands, and controlling reaction temperature. 3 / Cs 4 PbB 6 Water stability and thermal stability of nanocrystalline luminescent materials.

[0004] Although CsPbBr 3 / Cs 4 PbB 6 Nanocrystals exhibit excellent luminescent properties. However, there are many problems and contradictions in their preparation process. For example: if organic ligands are not added, the reaction nucleation will be difficult to control, and the resulting products may have inconsistent sizes and properties, which is not conducive to mass production; adding organic ligands is conducive to grain growth control, but the non-recyclable organic reagents will cause cost increases and environmental pollution; heating during the reaction is conducive to the reaction, but it will introduce additional costs. These problems cannot be taken into account at the same time, which greatly limits industrial applications. Therefore, it is of far-reaching significance to explore a preparation method that is simple to operate, has stable products, good reproducibility, and can be mass-produced to obtain efficient and stable perovskite nanocrystal luminescent materials. Summary of the invention

[0005] In view of the problems of the prior art, the present invention provides a method for preparing a perovskite nanocrystal luminescent material, which adopts a step-by-step preparation method through a precursor, has good reaction controllability, does not require the addition of organic ligands, and does not require heating during the reaction process. It has the characteristics of simple preparation, low cost, and suitability for large-scale production. The obtained perovskite nanocrystal luminescent material has a high quantum yield and good stability.

[0006] To achieve the above objectives, the first aspect of the present invention provides a high-stability inorganic perovskite nanocrystalline luminescent material APbX 3 / A 4 PbX 6 , where A is Na, K, Rb, Cs, B is Ge, Sn, Pb, Mn, Cu, Sb, Bi, and X is F, Cl, Br, I.

[0007] The APbX of the present invention 3 / A 4 PbX 6 It is a core-shell structure, with the core being APbX 3 , embedded in the A 4 PbX 6 interior.

[0008] The second aspect of the present invention provides a high-stability inorganic perovskite nanocrystalline luminescent material APbX as described in the first aspect. 3 / A 4 PbX 6 A preparation method comprising the following steps:

[0009] Step (1): mixing the precursor of A and the precursor of B with a solvent respectively, stirring at room temperature to obtain a precipitate, and post-treating to obtain a perovskite nanocrystal precursor;

[0010] Preferably, the precursor of A is AX, A 2 CO 3 , CH 3 COOA, the precursor of B is BX 2 、BCO 3 , B(CH 3 COO 2 ,

[0011] Preferably, the solvent is water, methanol, ethanol, acetone, N,N-dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide;

[0012] Preferably, the molar ratio of the precursor of A to the precursor of B is (0.5-6):1;

[0013] Preferably, the ratio of the precursor of A to the solvent is (0.1-0.5) mmol:10 mL;

[0014] Preferably, the stirring time is 2 to 60 minutes;

[0015] Preferably, the post-treatment is separation, washing or separation and drying;

[0016] Preferably, the solvent used for the washing is N,N-dimethylformamide, dimethyl sulfoxide, or N,N-dimethylacetamide;

[0017] Preferably, the drying temperature is 25 to 80° C., and the drying time is 10 min to 12 h.

[0018] Step (2): Mix the precursor obtained in step (1) with the precursor of B, add a solvent, stir at room temperature to obtain a precipitate, and post-treat to obtain ABX 3 / A 4 BX 6 Perovskite nanocrystal luminescent materials;

[0019] Preferably, the solvent is N,N-dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide;

[0020] Preferably, the stirring time is 10 to 240 minutes;

[0021] Preferably, the post-treatment is separation, washing or drying, grinding;

[0022] Preferably, the drying temperature is 25 to 80° C., and the drying time is 10 min to 24 h.

[0023] A third aspect of the present invention provides an application of a perovskite nanocrystal luminescent material, wherein the perovskite nanocrystal luminescent material is used to prepare a photoluminescent device, a laser optical device or a nonlinear optical device.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. The preparation method of the present invention is simple to operate, low in cost, easy to prepare in batches, suitable for industrial production, and greatly reduces the production cost of luminescent materials.

[0026] 2. In the preparation process of the perovskite nanocrystal luminescent material described in the present invention, no organic ligand needs to be added, which saves raw materials and does not require subsequent purification process.

[0027] 3. The perovskite nanocrystal luminescent material prepared by the method of the present invention has a narrow half-width and high purity of luminescent color, which can meet the requirements of practical applications and has broad application prospects in the fields of wide color gamut LED display, laser, nonlinear optics, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a photo of the perovskite nanocrystal luminescent material obtained in the present invention under natural light

[0029] Figure 2 This is the X-ray diffraction pattern of the perovskite nanocrystal luminescent material obtained in the present invention

[0030] Figure 3 The excitation spectrum and emission spectrum of the perovskite nanocrystal luminescent material obtained by the present invention are DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below by specific implementation methods. The embodiments are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0032] Example 1

[0033] A method for preparing perovskite nanocrystal luminescent material

[0034] (1) Weigh 0.6 mmol of CsBr (0.128 g) and 1 mmol of PbBr 2 (0.367 g) was placed in a 50 mL glass bottle, 3 mL of water and 10 mL of N,N-dimethylformamide were added, and the mixture was stirred at room temperature for 2 min. The solution was poured out, and the precipitate was dried at 60 °C for 10 min to obtain a perovskite nanocrystal precursor.

[0035] (2) The obtained perovskite precursor was mixed with 10 mL of N,N-dimethylformamide, and then 3.5 mmol of CsBr (0.745 g) was added. The mixture was stirred at room temperature for 10 min to obtain a precipitate. The solution was poured out, and the precipitate was dried at 60 ° C for 10 min. CsPbBr was obtained after grinding. 3 / Cs 4 PbB 6 Perovskite nanocrystal luminescent materials.

[0036] Example 2

[0037] A method for preparing luminescent perovskite nanocrystals

[0038] (1) Weigh 1 mmol of CsCO 3 (0.326 g) and 1 mmol of PbBr 2 (0.367 g) was placed in a 50 mL glass bottle, 5 mL of hydrobromic acid and 5 mL of ethanol were added, and the mixture was stirred for 5 min. The solution was poured out, and 5 mL of N,N-dimethylformamide was added to the precipitate in the glass bottle again. The mixture was shaken and washed, and the solution was poured out to obtain a perovskite nanocrystal precursor.

[0039] (2) The obtained perovskite precursor was mixed with 12 mL of N,N-dimethylformamide, and then 4 mmol of CsBr (0.851 g) was added. The mixture was stirred at room temperature for 10 min to obtain a precipitate. The precipitate and the solution were dried at 60 °C for 12 h and ground to obtain CsPbBr 3 / Cs 4 PbB 6 Perovskite nanocrystal luminescent materials.

[0040] Example 3

[0041] A method for preparing luminescent perovskite nanocrystals

[0042] (1) Weigh 0.8 mmol of CH 3 COOCs (0.154 g) and 1 mmol of Pb(CH 3 COO 2 (0.325 g) was placed in a 50 mL glass bottle, 3 mL of water, 3 mL of hydrobromic acid, 3 mL of methanol, and 3 mL of N,N-dimethylacetamide were added, and the mixture was stirred at room temperature for 5 min. The solution was poured out, and the precipitate was dried at 60 °C for 10 min to obtain a perovskite nanocrystal precursor.

[0043] (2) The obtained perovskite precursor was mixed with 10 mL of N,N-dimethylformamide, and then 5 mmol of CsBr (1.064 g) was added. The mixture was stirred at room temperature for 10 min to obtain a precipitate. The solution was poured out and the precipitate was dried at 25 °C for 12 h. CsPbBr was obtained after grinding. 3 / Cs4PbBr 6 Perovskite nanocrystal luminescent materials.

[0044] Example 4

[0045] A method for preparing luminescent perovskite nanocrystals

[0046] (1) Weigh 1 mmol of CsBr (0.213 g) and 1 mmol of PbBr 2 (0.367 g) was added to a 50 mL glass bottle, 2 mL of water and 8 mL of N, N-dimethylformamide were added, stirred at room temperature for 2 min, the solution was poured out, 10 mL of N, N-dimethylformamide was added to the precipitate in the glass bottle again, shaken and washed, and the solution was poured out again to obtain a perovskite nanocrystal precursor;

[0047] (2) The obtained perovskite precursor was mixed with 12 mL of N,N-dimethylformamide and 3.5 mmol of CH 3COOCs (0.672 g) and 3 ml hydrobromic acid were stirred at room temperature for 30 min to obtain a precipitate. The precipitate and the solution were dried at 50 °C for 12 h and ground to obtain CsPbBr 3 / Cs 4 PbB 6 Perovskite nanocrystal luminescent materials.

[0048] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a perovskite nanocrystal luminescent material, wherein the perovskite nanocrystal luminescent material is ABX3 / A4BX6, wherein A is Cs, B is Pb, and X is Br; The preparation method comprises the following steps: Step (1): adding a precursor of A and a precursor of B to a solvent respectively, stirring at room temperature to obtain a precipitate, and post-treating to obtain a perovskite nanocrystal precursor; the molar ratio of the precursor of A to the precursor of B is (0.5-6):1, and the ratio of the precursor of A to the solvent is (0.1-1) mmol:10 mL; the solvent is water, hydrobromic acid, methanol, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide; the stirring time is 2-60 min; the post-treatment is separation, washing or separation and drying; Step (2): Mix the perovskite nanocrystal precursor obtained in step (1) with the precursor of A, add a solvent, stir at room temperature to obtain a precipitate, and post-treat to obtain the APbX3 / A4PbX6 perovskite nanocrystal luminescent material, wherein the solvent is N,N-dimethylformamide.

2. The method for preparing the perovskite nanocrystal luminescent material according to claim 1, characterized in that: In step (1) and step (2), the precursor of A is AX, A2CO3, CH3COOA, and the precursor of B is BX2, BCO3, B(CH3COO)2.

3. The method for preparing the perovskite nanocrystal luminescent material according to claim 1, characterized in that: The solvent used for washing in step (1) is N,N-dimethylformamide or N,N-dimethylacetamide; the drying temperature is 25 to 80° C. and the drying time is 10 min to 12 h.

4. The method for preparing the perovskite nanocrystal luminescent material according to claim 1, characterized in that: The stirring time in step (2) is 10 to 240 minutes; the post-treatment is separation, washing or drying, and grinding.

5. The method for preparing the perovskite nanocrystal luminescent material according to claim 1, characterized in that: The drying temperature in step (2) is 25 to 80° C. and the drying time is 10 min to 24 h.

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