Preparation method of perovskite nanocrystalline composite luminescent material

Abstract

The invention discloses a preparation method of a perovskite nanocrystalline composite luminescent material, which adopts a way of step-by-step compounding of a precursor and low-temperature calcination after grinding, has good reaction controllability, does not need to add an organic ligand, and has the characteristics of simple preparation, low cost and suitability for large-scale production. The obtained perovskite nanocrystalline composite luminescent material has high quantum yield and good stability, and can be applied to photoluminescent devices, laser devices 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 nanocrystal composite luminescent material. Background Art

[0002] All-inorganic metal halide perovskite CsPbX3 (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 CsPbX3 nanocrystals for the first time. The luminescence range can cover the entire visible light region, and the quantum efficiency in the colloidal state is as high as 50% to 90%. However, when extracting perovskite CsPbX3 (X = Cl, Br, I) nanocrystals, as the colloidal state is transformed into solid powder, the fluorescence is sharply quenched due to the shedding of surface ligands. In addition, perovskite nanocrystals are also very unstable under the influence of environmental factors such as light, heat, water, and oxygen, and the luminescence is easily quenched. In order to solve this problem, the researchers embedded CsPbBr3 into a series of mesoporous silicon with different pore sizes such as SBA-15, MCM-41, and MSU-H to form a composite structure of CsPbBr3@mesoporous silicon. The surface of the perovskite nanocrystals was passivated by the mesoporous material, and the obtained samples had a higher luminescence quantum efficiency. At the same time, the researchers also compounded and calcined the perovskite precursor raw materials (CsBr, PbBr2) with MCM-41, and by controlling the reaction temperature, they further improved the water stability and thermal stability of the (CsPbBr3@mesoporous silicon) luminescent material.

[0004] Although CsPbBr3@mesoporous silicon luminescent materials show excellent luminescent properties and good stability. However, there are many problems in its preparation process and the sample itself. For example: the method of first preparing perovskite quantum dots and then compounding the quantum dots with mesoporous silicon is complicated: if the hot injection method is used, a large amount of organic solvent will be used, and the operation is complicated; if the anti-solvent method is used, the process will also use a large amount of organic solvent; which is not conducive to batch preparation; and the method of directly calcining the perovskite precursor raw materials (CsBr, PbBr2) with the template has the following problems: for example, the luminescent performance of the product is insufficient, and the product needs to be washed with hydrofluoric acid (HF) to reduce the particle size and improve the luminescent performance, etc., which greatly limits the industrial application. Therefore, exploring a preparation method that is simple to operate, can be scalably produced, and the resulting product has good luminescent performance and stability, and good preparation reproducibility is of great significance to promote the application of perovskite nanocrystalline 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 composite luminescent material, which adopts a method of compounding a precursor with mesoporous silicon and hydrolyzed silicon in sequence and then calcining at low temperature, and the obtained perovskite nanocrystal luminescent material has high quantum yield and good stability. The reaction is well controllable, no organic ligand needs to be added, and the preparation is simple, green and environmentally friendly, low cost, and suitable for large-scale production.

[0006] To achieve the above-mentioned purpose, the first aspect of the present invention provides a highly efficient and stable perovskite nanocrystal composite light-emitting material, including perovskite nanocrystals, mesoporous silicon and hydrolyzed silicon, wherein the perovskite nanocrystals are the light-emitting core, and the mesoporous silicon and hydrolyzed silicon are the coating layers of the perovskite nanocrystals; wherein the perovskite is CsPbBr3 or Cs4PbBr6, the mesoporous silicon is a porous silicon oxide material with a pore size range of (2-20nm), and the hydrolyzed silicon is silicon dioxide obtained by hydrolysis of the silicon-containing precursor TEOS or APTES.

[0007] The second aspect of the present invention provides a method for preparing the perovskite nanocrystal composite light-emitting material as described in the first aspect, which comprises the following steps:

[0008] Step (1): Dissolve CsBr and PbBr2 in water and DMF (or DMSO) respectively. After the two are dissolved, add an appropriate amount of mesoporous silicon to the DMF (or DMSO) solution of PbBr2 and continue to stir evenly; then add the aqueous solution of CsBr to the above DMF (or DMSO) solution of PbBr2 and mesoporous silicon and continue to stir;

[0009] Preferably, the molar ratio of CsBr and PbBr2 precursors is (0.5-6):1;

[0010] Preferably, the volume ratio of CsBr to water is 1 mmol / ml: (1 to 10 ml);

[0011] Preferably, the volume ratio of PbBr2 to DMF (or DMSO) is 1 mmol / ml: (4-15 ml);

[0012] Preferably, the mass ratio of PbBr2 to mesoporous silicon is 0.367 g: (0.5 to 4 g);

[0013] Preferably, the stirring time is 2 to 10 minutes;

[0014] Step (2): adding an appropriate amount of APTES or TEOS to the mixed solution obtained in step (1), stirring at room temperature for 5 to 30 minutes, naturally evaporating to dryness or slowly drying at 20 to 70° C., and grinding to obtain a calcined precursor;

[0015] Preferably, the amount of APTES is (0.5-2 ml) compared to the amount of PbBr2: 1 mmol;

[0016] Preferably, the amount of TEOS is compared to the amount of PbBr2 (1-4 ml): 1 mmol;

[0017] Step (3): calcining the calcined precursor obtained in step (2) at low temperature and cooling it in the furnace to obtain a perovskite nanocrystal composite luminescent material.

[0018] Preferably, the calcination temperature range is 400-800°C;

[0019] Preferably, the calcination time ranges from 20 to 120 min;

[0020] A third aspect of the present invention provides an application of a perovskite nanocrystal composite luminescent material, wherein the perovskite nanocrystal composite luminescent material is used to prepare a photoluminescent device, a laser optical device or a nonlinear optical device.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The preparation method described in the present invention is simple to operate, low in cost, easy to prepare in batches, suitable for industrial production, and can significantly reduce the production cost of luminescent materials.

[0023] 2. In the preparation process of the perovskite nanocrystal composite luminescent material described in the present invention, no organic ligand needs to be added, thus saving raw materials.

[0024] 3. The perovskite nanocrystal composite luminescent material prepared by the method of the present invention has a narrow half-width, high luminescent color purity, good stability to water, light and heat, can meet the requirements of practical applications, and has broad application prospects in wide color gamut LED display, laser, nonlinear optics and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a photo of the perovskite nanocrystal composite luminescent material obtained in the present invention (packed in a sample bag)

[0026] Figure 2 This is the X-ray diffraction pattern of the perovskite nanocrystal composite luminescent material obtained in the present invention

[0027] Figure 3 The excitation spectrum and emission spectrum of the perovskite nanocrystal composite luminescent material obtained by the present invention are DETAILED DESCRIPTION

[0028] 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.

[0029] Example 1

[0030] (1) Weigh 1 mmol of CsBr (0.2128 g) and dissolve it in 5 ml of H2O to obtain a CsBr aqueous solution. Separately weigh 1 mmol of PbBr2 (0.367 g) and dissolve it in 8 mL of DMF. Then, add 2 g of SBA-15 to the PbBr2 DMF solution and stir well. Then, add the prepared CsBr aqueous solution and stir well.

[0031] In the above mixed system, 2 ml APTES and 4 ml TEOS were added and stirred for 15 min to obtain a gel-like solid. Subsequently, the solid was dried in an oven at 50 °C for 5 h, and the obtained solid was ground to obtain a calcined precursor powder;

[0032] The obtained calcined precursor powder was then calcined at 650° C. for 60 min in a box furnace to obtain a perovskite nanocrystal composite luminescent material.

[0033] Example 2

[0034] (1) Weigh 4 mmol of CsBr (0.8512 g) and dissolve it in 8 ml of H2O to obtain a CsBr aqueous solution. Separately weigh 1 mmol of PbBr2 (0.367 g) and dissolve it in 8 mL of DMF. Then, add 2 g of SBA-15 to the PbBr2 DMF solution and stir well. Then, add the prepared CsBr aqueous solution and stir well.

[0035] In the above mixed system, 2 ml APTES and 4 ml TEOS were added and stirred for 15 min to obtain a gel-like solid. Subsequently, the solid was dried in an oven at 50 °C for 8 h, and the obtained solid was ground to obtain a calcined precursor powder;

[0036] The obtained calcined precursor powder was then calcined at 650° C. for 60 min in a box furnace to obtain a perovskite nanocrystal composite luminescent material.

[0037] Example 3

[0038] (1) Weigh 0.5 mmol of CsBr (0.1064 g) and dissolve it in 3 ml of H2O to obtain a CsBr aqueous solution. Separately weigh 1 mmol of PbBr2 (0.367 g) and dissolve it in 8 mL of DMF. Then, add 1 g of MCM-41 to the PbBr2 DMF solution and stir well. Then, add the prepared CsBr aqueous solution and stir well.

[0039] In the above mixed system, 2 ml APTES and 5 ml TEOS were added and stirred for 15 min to obtain a gel-like solid. Subsequently, the solid was dried in an oven at 50 °C for 4 h, and the obtained solid was ground to obtain a calcined precursor powder;

[0040] The obtained calcined precursor powder was then calcined at 650° C. for 60 min in a box furnace to obtain a perovskite nanocrystal composite luminescent material.

[0041] Example 4

[0042] (1) Weigh 3 mmol of CsBr (0.6384 g) and dissolve it in 5 ml of H2O to obtain a CsBr aqueous solution. Weigh 2 mmol of PbBr2 (0.367 g) and dissolve it in 8 mL of DMF. Then add 4 g of mesoporous silica gel to the PbBr2 DMSO solution and stir well. Then add the prepared CsBr aqueous solution and stir well.

[0043] In the above mixed system, 2 ml APTES and 4 ml TEOS were added and stirred for 15 min to obtain a gel-like solid. Subsequently, the solid was dried in an oven at 50 °C for 5 h, and the obtained solid was ground to obtain a calcined precursor powder;

[0044] The obtained calcined precursor powder was then calcined at 650° C. for 60 min in a box furnace to obtain a perovskite nanocrystal composite luminescent material.

[0045] 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 perovskite nanocrystal composite luminescent material, characterized in that: The perovskite nanocrystal composite luminescent material comprises perovskite nanocrystals, mesoporous silicon and hydrolyzed silicon, wherein the perovskite nanocrystals are luminescent cores, the mesoporous silicon and hydrolyzed silicon are coating layers of the perovskite nanocrystals, the mesoporous silicon is an intermediate layer, and the hydrolyzed silicon is an outer layer.

2. The perovskite composite light-emitting material according to claim 1, characterized in that: The perovskite nanocrystal is one or both of CsPbBr3 and Cs4PbBr6; the mesoporous silicon is a porous silicon-containing oxide material with a pore size range of (2-20nm); and the hydrolyzed silicon is silicon dioxide obtained by hydrolyzing a silicon-containing precursor.

3. The perovskite composite light-emitting material according to claim 1, characterized in that: The mesoporous silica is one or more of MCM-41, SBA-15, and mesoporous silica gel.

4. A method for preparing a perovskite nanocrystal composite luminescent material, characterized in that: The following steps are involved: Step (1): dissolving cesium bromide CsBr and lead bromide PbBr2 in water H2O and N,N-dimethylformamide DMF (or dimethyl sulfoxide DMSO) respectively. After the dissolution, add an appropriate amount of mesoporous silicon to the DMF (or DMSO) solution containing PbBr2 and continue to stir evenly; add the aqueous solution of CsBr to the above DMF (or DMSO) solution of PbBr2 and mesoporous silicon and continue to stir; Step (2): adding an appropriate amount of hydrolyzed silicon precursor to the mixed solution obtained in step (1), stirring at room temperature, naturally evaporating to dryness or slowly drying at 20 to 70° C., and grinding to obtain a calcined precursor; Step (3): calcining the calcined precursor obtained in step (2) at low temperature and cooling it in the furnace to obtain a perovskite nanocrystal composite luminescent material.

5. The preparation method according to claim 4, characterized in that: The molar ratio of the CsBr and PbBr2 precursors in step (1) is (0.5-6):

1.

6. The preparation method according to claim 4, characterized in that: The volume ratio of the amount of CsBr to water in step (1) is 1 mmol: (1-10 ml).

7. The preparation method according to claim 4, characterized in that: The volume ratio of the amount of PbBr2 to DMF (or DMSO) in step (1) is 1 mmol: (4-15 ml).

8. The preparation method according to claim 4, characterized in that: The mass ratio of PbBr2 to mesoporous silicon in step (1) is 1 mmol: (0.5-4 g).

9. The preparation method according to claim 4, characterized in that: The hydrolyzed silicon precursor in step (2) is one or both of 3-aminopropyltriethoxysilane APTES and tetraethoxysilane TEOS.

10. The preparation method according to claim 4, characterized in that: The amount of APTES in step (2) is compared to the amount of PbBr2 (0.5-2 ml): 1 mmol.

11. The preparation method according to claim 4, characterized in that: The amount of TEOS in step (2) is compared to the amount of PbBr2 (1-4 ml): 1 mmol.

12. The preparation method according to claim 4, characterized in that: The stirring time after adding the hydrolyzed silicon precursor in step (2) is 5 to 30 minutes.

13. The preparation method according to claim 4, characterized in that: The calcination temperature range of the powder precursor in step (3) is 400-800°C.

14. The preparation method according to claim 4, characterized in that: The calcination time of the powder precursor in step (3) is in the range of 20 to 180 minutes.

15. The perovskite nanocrystal composite light-emitting material according to claim 1, characterized in that: The perovskite nanocrystal composite luminescent material is used for making photoluminescent devices, laser optical devices or nonlinear optical devices.

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