Preparation method of all-inorganic perovskite nanocrystals based on liquid phase pulsed laser induction

Abstract

The invention discloses a preparation method of all-inorganic perovskite nanocrystals based on liquid phase pulse laser induction, belonging to the technical field of perovskite luminescent materials. The preparation method is: using Cs2CO3 and PbBr2 as reaction precursors, adding n-hexane, oleic acid and oleylamine, and performing irradiation reaction under a 1064nm pulse laser beam; the product after the irradiation reaction is centrifuged once to obtain a supernatant, and the supernatant is centrifuged twice to obtain a solid product perovskite nanocrystal. The invention successfully prepares all-inorganic perovskite nanocrystals with high fluorescence quantum yield under the condition of no inert gas protection by using liquid phase pulse laser radiation technology.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite luminescent materials, and more specifically to a method for preparing all-inorganic perovskite nanocrystals based on liquid phase pulse laser induction. Background Art

[0002] Information visualization is one of the main development directions of future information revolution technology. As the core component of the display device in information visualization, light-emitting diodes are one of the important carriers of information, which puts forward higher requirements on the performance of new light-emitting diodes in diversified display, accurate integration and information transmission. Developing new luminescent materials with controllable and easy-to-adjust spectrum, high luminous efficiency, high color purity and solution preparation is one of the important ways to achieve the upgrading of diversified and intelligent information display technology.

[0003] Metal halide perovskite (hereinafter referred to as perovskite) is an emerging optoelectronic semiconductor material in recent years. Its general chemical formula is ABX3, where A represents a monovalent cation (usually an alkali metal cation Cs + , methylammonium cation MA + and formamidinium cation FA + ), B represents a divalent metal cation (Pb 2+ ,Sn 2+ etc.), X is a halogen anion Cl that forms a bond with the metal ion at position B - Br - ,I - . Among them, the all-inorganic perovskite nanocrystals synthesized by wet chemical methods exhibit excellent optical properties, such as high quantum yield, narrow half-peak width of luminescence (<30nm), continuously adjustable luminescence spectrum (emission in the full spectrum range from ultraviolet to near-infrared region), wide color gamut, etc. Therefore, all-inorganic perovskite nanocrystals show great application prospects in optoelectronic fields such as light-emitting diodes, photovoltaics, lasers and photoelectric detection. Especially for luminescence, by regulating the composition and dimension of the halogen of all-inorganic perovskite nanocrystals, full-spectrum emission covering the visible light range and excellent monochromaticity can be achieved, so it has received widespread attention from researchers. Unlike traditional metal sulfide-based nanocrystals, the preparation methods of high-quality all-inorganic perovskite nanocrystals are relatively limited.

[0004] At present, the hot injection method based on high temperature is the most widely used method to obtain all-inorganic perovskite nanocrystals with high fluorescence quantum yield. However, the hot injection method is cumbersome, generally needs to be carried out in an inert atmosphere and requires a high reaction temperature, which poses a challenge to the large-scale preparation of all-inorganic perovskite nanocrystals. Summary of the invention

[0005] In view of the above problems, the present invention provides a method for preparing all-inorganic perovskite nanocrystals based on liquid-phase pulsed laser induction, and successfully prepares all-inorganic perovskite nanocrystals with high fluorescence quantum yield under the condition of no inert gas protection by using liquid-phase pulsed laser radiation technology.

[0006] The purpose of the present invention is to provide a method for preparing all-inorganic perovskite nanocrystals based on liquid phase pulse laser induction, which is prepared according to the following steps:

[0007] Step 1, using Cs2CO3 and PbBr2 as reaction precursors, adding n-hexane, oleic acid and oleylamine, and performing irradiation reaction under a 1064nm pulsed laser beam;

[0008] Step 2, centrifuging the product of the irradiation reaction once to obtain a supernatant, and then centrifuging the supernatant a second time to obtain a solid product, perovskite nanocrystals.

[0009] Preferably, the addition ratio of Cs2CO3, PbBr2, and n-hexane is 0.1-0.2mmol:0.1-0.2mmol:5-10mL;

[0010] The volume ratio of n-hexane, oleic acid and oleylamine is 5-10:0.5-1.5:0.5-1.

[0011] Preferably, the addition ratio of Cs2CO3, PbBr2, and n-hexane is 0.1mmol:0.1mmol:10mL;

[0012] The volume ratio of n-hexane, oleic acid and oleylamine is 10:1.5:0.5.

[0013] Preferably, the radiation reaction time is 15-30 min.

[0014] Preferably, the radiation reaction time is 15 minutes.

[0015] Preferably, one centrifugation treatment is performed at 1000-2000 rpm for 5-10 min.

[0016] Preferably, the secondary centrifugation treatment is performed at 7000-9000 rpm for 5-10 min.

[0017] Preferably, the perovskite nanocrystals are dispersed in n-hexane to obtain a perovskite nanocrystal solution.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] Unlike traditional heat treatment technology, laser irradiation synthesis is based on the photothermal effect induced by a pulsed laser beam, which rapidly cools down after laser irradiation at a specific location, thereby precisely regulating the specific surface interface and microstructure of the synthetic material. The present invention successfully prepares all-inorganic perovskite nanocrystals with high fluorescence quantum yield using liquid phase pulsed laser irradiation technology without inert gas protection.

[0020] The preparation method provided by the present invention has a simple operation process and a short preparation cycle, and the present invention realizes the direct preparation of all-inorganic perovskite nanocrystals in n-hexane. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the present invention using liquid phase pulse laser to prepare all-inorganic perovskite nanocrystals;

[0022] Figure 2 The fluorescence and corresponding absorption spectra of all-inorganic perovskite nanocrystals prepared by liquid phase pulse laser in Example 1 are the actual pictures of perovskite nanocrystal colloidal solution under natural light and under ultraviolet light excitation;

[0023] Figure 3 This is a transmission electron microscope image of the all-inorganic perovskite nanocrystal prepared by liquid phase pulse laser in Example 1. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example 1

[0026] Step 1, place a certain amount of reaction precursors 0.1mmol Cs2CO3 and 0.1mmol PbBr2 in a reaction bottle, add 10mL n-hexane, 1mL oleic acid and 0.5mL oleylamine;

[0027] Step 2, placing the above reaction system under a 1064nm pulsed laser beam for 15 minutes;

[0028] Step 3: Transfer the product after the irradiation reaction to a centrifuge, centrifuge at 2000 rpm for 10 min for the first time, and retain the supernatant; then centrifuge again at 7000 rpm for 10 min, retain the solid product, and disperse the solid product in n-hexane to obtain a perovskite nanocrystal solution.

[0029] Example 2

[0030] Step 1, place a certain amount of reaction precursors 0.15mmol Cs2CO3 and 0.15mmol PbBr2 in a reaction bottle, add 5mL n-hexane, 1.5mL oleic acid and 1mL oleylamine;

[0031] Step 2, placing the above reaction system under a 1064nm pulsed laser beam for irradiation for 20 minutes;

[0032] Step 3: Transfer the product after the irradiation reaction to a centrifuge, centrifuge at 1000 rpm for 8 min for the first time, and retain the supernatant; then centrifuge again at 9000 rpm for 5 min, retain the solid product, and disperse the solid product in n-hexane to obtain a perovskite nanocrystal solution.

[0033] Example 3

[0034] Step 1, place a certain amount of reaction precursors 0.2mmol Cs2CO3 and 0.2mmol PbBr2 in a reaction bottle, add 8mL n-hexane, 0.5mL oleic acid and 0.5mL oleylamine;

[0035] Step 2, placing the above reaction system under a 1064nm pulsed laser beam for irradiation for 30 minutes;

[0036] Step 3: Transfer the product after the irradiation reaction to a centrifuge, centrifuge at 1500 rpm for 5 min for the first time, and retain the supernatant; then centrifuge again at 8000 rpm for 7 min, retain the solid product, and disperse the solid product in n-hexane to obtain a perovskite nanocrystal solution.

[0037] Example 4

[0038] Step 1, place a quantitative amount of reaction precursors 0.2mmol Cs2CO3 and 0.1mmol PbBr2 in a reaction bottle, add 10mL n-hexane, 1mL oleic acid and 0.5mL oleylamine;

[0039] Step 2, placing the above reaction system under a 1064nm pulsed laser beam for irradiation for 25 minutes;

[0040] Step 3: Transfer the product after the irradiation reaction to a centrifuge, centrifuge at 2000 rpm for 5 min for the first time, and retain the supernatant; then centrifuge again at 8000 rpm for 7 min, retain the solid product, and disperse the solid product in n-hexane to obtain a perovskite nanocrystal solution.

[0041] Figure 1Schematic diagram of the preparation of all-inorganic perovskite nanocrystals by liquid phase pulse laser. After the precursor powder and n-hexane are mixed, they are irradiated with liquid phase pulse laser for a certain period of time and then purified by centrifugation to obtain a colloidal solution of all-inorganic perovskite nanocrystals. The high-energy laser breaks the bulk material into small particles, which are then reassembled and grown under the guidance of the laser. The ligands are further coated on their surfaces to achieve the preparation of nanocrystals.

[0042] Figure 2 The fluorescence and corresponding absorption spectra of the all-inorganic perovskite nanocrystals prepared by liquid phase pulsed laser in Example 1 (left illustration: a real picture of the perovskite nanocrystal colloidal solution under natural light; right illustration: a real picture of the perovskite nanocrystal colloidal solution under ultraviolet light excitation). The nanocrystals obtained based on the laser irradiation method exhibit a symmetrical fluorescence emission spectrum with a central emission peak at about 505nm. The absorption spectrum shows a small absorption peak at 485nm. The fluorescence quantum yield results show that the fluorescence quantum yield of the obtained perovskite nanocrystal solution is as high as 90.5%, showing excellent fluorescence properties.

[0043] Figure 3 This is a transmission electron microscope image of the all-inorganic perovskite nanocrystals prepared by liquid phase pulse laser in Example 1. The obtained nanocrystals have a hexagonal morphology and a uniform particle size distribution.

[0044] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0045] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing all-inorganic perovskite nanocrystals based on liquid phase pulsed laser induction, characterized in that: Prepared according to the following steps: Step 1, using Cs2CO3 and PbBr2 as reaction precursors, adding n-hexane, oleic acid and oleylamine, and irradiating under a 1064nm pulsed laser beam; the addition ratio of Cs2CO3, PbBr2, and n-hexane is 0.1-0.2mmol: 0.1-0.2mmol: 5-10mL; the volume ratio of n-hexane, oleic acid and oleylamine is 5-10: 0.5-1.5: 0.5-1; the radiation reaction time is 15-30min; Step 2, centrifuging the product after the irradiation reaction to obtain a supernatant, and then centrifuging the supernatant a second time to obtain a solid product, perovskite nanocrystals.

2. The method for preparing all-inorganic perovskite nanocrystals based on liquid phase pulsed laser induction according to claim 1, characterized in that: The addition ratio of Cs2CO3, PbBr2, and n-hexane was 0.1mmol:0.1mmol:10mL; The volume ratio of n-hexane, oleic acid and oleylamine is 10:1.5:0.

5.

3. The method for preparing all-inorganic perovskite nanocrystals based on liquid phase pulsed laser induction according to claim 1, characterized in that: The radiation reaction time is 15 minutes.

4. The method for preparing all-inorganic perovskite nanocrystals based on liquid phase pulsed laser induction according to claim 1, characterized in that: One centrifugation treatment is performed at 1000-2000 rpm for 5-10 minutes.

5. The method for preparing all-inorganic perovskite nanocrystals based on liquid phase pulsed laser induction according to claim 1, characterized in that: The secondary centrifugation treatment is performed at 7000-9000 rpm for 5-10 min.

6. The method for preparing all-inorganic perovskite nanocrystals based on liquid phase pulsed laser induction according to claim 1, characterized in that: The perovskite nanocrystals are dispersed in n-hexane to obtain a perovskite nanocrystal solution.

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