A micro perovskite light-emitting unit and its preparation method and application

Abstract

The present invention discloses a micro-perovskite light-emitting unit and its preparation method and application. The method comprises: (a) coating a perovskite precursor solution containing a mixed amine halide on a substrate and heat-treating the solution to form a perovskite light-emitting layer; the mixed amine halide comprises at least a methylamine halide; and (b) pattern-etching the perovskite light-emitting layer with a laser beam to obtain a micro-perovskite light-emitting unit. The methylamine halide vaporizes, decomposing the perovskite to produce an optically inactive and insulating inorganic barrier layer. The laser-etched portion of the perovskite decomposes and simultaneously forms a micro-nano perovskite light-active pattern.

Description

Technical Field

[0001] The present invention belongs to the technical field of light-emitting diodes and relates to a perovskite light-emitting unit, and in particular to a micro perovskite light-emitting unit and a preparation method and application thereof. Background Art

[0002] With breakthroughs in technologies such as 3D display and virtual reality, higher demands are being placed on display technology, driving it towards high brightness, high resolution, and ease of processing. Halide perovskite materials have garnered widespread attention in recent years due to their advantages, including high yield of fluorescent quantum dots, high defect tolerance, excellent carrier transport properties, and ease of processing. However, due to the poor stability of perovskites, the micro- and nano-fabrication of perovskite materials to construct micro- and nano-luminescent units remains a major challenge.

[0003] Currently, the main methods for fabricating micro-nano light-emitting units are inkjet printing, transfer printing, and photolithography. However, these methods often face challenges such as complex process flows, high processing costs, strict requirements on processing equipment parameters, and poor compatibility with perovskites. Therefore, addressing the poor stability of perovskite materials and developing micro-nano processing methods that match them to meet the requirements of new display technologies is an urgent issue that needs to be addressed.

[0004] CN110943186B discloses a perovskite patterned film and its preparation method and display device. In the method for preparing the perovskite patterned film disclosed in the invention, a perovskite precursor, a polymer monomer, a photoinitiator and a cross-linking agent are first mixed to form a pre-polymerized mixed colloidal solution; the pre-polymerized mixed colloidal solution is then coated on a substrate having a retaining wall to prepare a pre-polymerized mixture film layer; secondly, under the shielding of a photomask, the pre-polymerized mixture film layer is irradiated with ultraviolet light to form a partially polymerized mixture film layer; thereafter, an organic solvent is used to spray the polymerized mixture film layer to dissolve and remove the unpolymerized portion to form a polymerized mixture film layer; finally, the first organic solvent in the polymerized mixture film layer is removed to obtain a perovskite patterned film. However, the disclosed preparation method has a complex process, low production efficiency and difficulty in achieving large-area patterned preparation.

[0005] CN114988463A discloses a method for patterned assembly of halide perovskites. This method introduces chiral molecules into the preparation of perovskite nanocrystals. The enantioselective interaction between chiral molecules of different conformations and oleic acid on the perovskite surface induces a two-dimensional self-assembly effect in the perovskite material. The chiral amino functional groups on the surface of the chiral molecules form hydrogen bonds with oleylamine, thereby achieving patterned three-dimensional self-assembly of the perovskite nanocrystals. While this method utilizes the steady-state equilibrium of Gibbs free energy in the combination system of grain anisotropy and chiral molecules to drive the induced three-dimensional self-assembly of the perovskite material, the controllability of the pattern is poor, making it difficult to quickly and diversely prepare patterns.

[0006] CN111273518B discloses a method for blue-light patterning of halogen perovskite nanocrystals based on laser direct writing. This method utilizes localized photoinduction of focused laser light to induce localized anion exchange, and programmed movement of a motorized translation stage achieves blue-light fluorescence patterning. Compared to existing halogen perovskite patterning methods, this method achieves blue-light patterning of nanocrystals and regulation of fluorescence spectral peak positions. However, the preparation process requires the use of highly toxic halogenated alkanes, and the prepared mixed halogen perovskite exhibits spectral drift, limiting the practical application of perovskite patterns.

[0007] Therefore, it is urgent to develop a method that is simple in process and can prepare large-area micro perovskite light-emitting units. Summary of the Invention

[0008] In view of the above-mentioned defects in the prior art, the present invention provides a method for preparing a micro perovskite light-emitting unit.

[0009] To achieve the above object, the present invention provides a method for preparing a micro perovskite light-emitting unit, comprising the following steps:

[0010] (a) coating a perovskite precursor solution containing a mixed amine halide on a substrate, and forming a perovskite light-emitting layer through heat treatment; the mixed amine halide contains at least methylamine halide;

[0011] (b) Patterning and etching the perovskite light-emitting layer using a laser beam to obtain a micro perovskite light-emitting unit.

[0012] As a preferred technical solution of the present invention, the mixed halogenated amines further include a mixture of one or more of ethylamine halides, formamidine halides, dimethylamine halides, propylamine halides, butylamine halides, benzylamine halides, phenylethylamine halides, naphthylmethylamine halides and naphthylethylamine halides;

[0013] Preferably, the molar proportion of the methylamine halide in the mixed amine halide is 5%-100%;

[0014] Preferably, the amine halide is a mixture of one or more selected from the group consisting of ammonium chloride, ammonium bromide and ammonium iodide, and its concentration in the perovskite precursor solution is 0.05-5.0 mol / L.

[0015] As a preferred technical solution of the present invention, the solute of the perovskite precursor solution is a mixture of one or more selected from lead salts and stannous salts, the lead salts include lead halide, lead acetate and lead formate, and the stannous salts include stannous halide, stannous acetate and stannous formate;

[0016] Preferably, the solvent of the perovskite precursor solution is a mixture of one or more selected from dimethyl sulfoxide, formamide, butyrolactone and methyl pyrrolidone;

[0017] Preferably, the molar ratio of the solute in the perovskite precursor solution to the methylamine halide is 0.5 to 5:1.

[0018] As a preferred technical solution of the present invention, the heat treatment is heating at 80-110°C for 5-10 minutes;

[0019] Preferably, the perovskite precursor solution is subjected to a sizing treatment during coating;

[0020] Preferably, an anti-solvent is added dropwise during the coating treatment, and the anti-solvent is one or a mixture of several selected from ethyl acetate, toluene, chlorobenzene and chloroform.

[0021] As a preferred technical solution of the present invention, the thickness of the perovskite light-emitting layer is 10 nm-100 μm.

[0022] As a preferred technical solution of the present invention, the wavelength of the laser beam is 0.3-20 μm, the average power is 0.1-100 W, the pulse width is 1-500 ns, the laser frequency is 1-1000 kHz, the focused spot diameter is 0.1-100 μm and the spot moving speed is 0.01-20 mm / s;

[0023] Preferably, the distance between the perovskite light-emitting layer and the laser beam light source is 1-100 cm.

[0024] Another object of the present invention is to provide a micro perovskite light-emitting unit, which is prepared by the above-mentioned preparation method.

[0025] Optimally, the resolution of the micro perovskite light-emitting unit is 300-5000 PPI.

[0026] Another object of the present invention is to provide an application of a micro perovskite light-emitting unit for making a light-emitting diode.

[0027] Optimally, the light-emitting diode includes an indium tin oxide substrate, a hole injection layer, a hole transport layer, a perovskite layer, an electron transport layer and a metal electrode stacked in sequence, and the perovskite layer is the micro perovskite light-emitting unit.

[0028] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: the preparation method of the micro perovskite light-emitting unit of the present invention adopts a perovskite precursor solution containing a mixed amine halide and the mixed amine halide contains at least methylamine halide to form a perovskite light-emitting layer and cooperates with laser etching to vaporize the methylamine halide and decompose the perovskite to produce an optically inactive and insulating inorganic barrier layer, so that the laser-etched part of the perovskite decomposes and forms a micro-nano perovskite photoactive pattern.

[0029] Compared to traditional photolithography for producing light-emitting layer patterns, this invention innovatively utilizes laser decomposition of perovskite to produce an optically inactive insulating barrier layer to prepare micro-perovskite light-emitting units. This solves the problem of perovskite light-emitting layer deactivation caused by the poor compatibility between traditional photolithography and perovskite materials. Without the need for photoresist, this not only simplifies the processing and improves processing efficiency, but also makes it suitable for large-area patterning. Compared to the process of producing patterns using pre-synthesized perovskite quantum dots through ligand self-assembly, this invention can easily achieve the controllable preparation of a variety of patterns by regulating the laser spot diameter and movement rate, and has strong plasticity in pattern preparation.

[0030] The micro perovskite light-emitting unit prepared by the present invention can be used to prepare light-emitting diodes, which helps to improve the resolution of perovskite display devices; the optically inactive and insulating inorganic barrier layer produced by the decomposition of perovskite is used to isolate the contact between the hole transport layer and the electron transport layer, which is beneficial to suppress leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the process for preparing a micro perovskite light-emitting unit of the present invention;

[0032] Figure 2 Schematic diagram of the structure of the perovskite light-emitting layer of the present invention;

[0033] Figure 3 This is a schematic structural diagram of the micro perovskite light-emitting unit of the present invention;

[0034] Figure 4 Schematic diagram of the structure of the light emitting diode of the present invention. DETAILED DESCRIPTION

[0035] The present invention provides a method for preparing a micro-perovskite light-emitting unit, comprising the following steps: (a) applying a perovskite precursor solution containing a mixed amine halide to a substrate and heat-treating the solution to form a perovskite light-emitting layer; the mixed amine halide comprises at least a methylamine halide; and (b) pattern-etching the perovskite light-emitting layer using a laser beam to obtain a micro-perovskite light-emitting unit. By using a perovskite precursor solution containing a mixed amine halide, wherein the mixed amine halide comprises at least a methylamine halide, to form the perovskite light-emitting layer and coordinating the laser etching, the methylamine halide is vaporized, and the perovskite is decomposed to produce an optically inactive and insulating inorganic barrier layer. This allows the laser-etched portion of the perovskite to decompose and simultaneously form a micro-nano perovskite photoactive pattern. Compared to traditional photolithography for producing light-emitting layer patterns, this invention innovatively utilizes laser decomposition of perovskite to produce an optically inactive insulating barrier layer to prepare micro-perovskite light-emitting units. This solves the problem of perovskite light-emitting layer deactivation caused by the poor compatibility between traditional photolithography and perovskite materials. Without the need for photoresist, this not only simplifies the processing and improves processing efficiency, but also makes it suitable for large-area patterning. Compared to the process of producing patterns using pre-synthesized perovskite quantum dots through ligand self-assembly, this invention can easily achieve the controllable preparation of a variety of patterns by regulating the laser spot diameter and movement rate, and has strong plasticity in pattern preparation.

[0036] Optimally, the mixed amine halide further comprises a mixture of one or more of ethylamine halide, formamidine halide, dimethylamine halide, propylamine halide, butylamine halide, benzylamine halide, phenylethylamine halide, naphthylamine halide and naphthylethylamine halide; the molar proportion of the methylamine halide in the mixed amine halide is 5%-100% (preferably 30%-100%); the amine halide is a mixture of one or more selected from ammonium chloride, ammonium bromide and ammonium iodide, and its concentration in the perovskite precursor solution is 0.05-5.0 mol / L (preferably 0.1-1.0 mol / L).

[0037] Optimally, the solute of the perovskite precursor solution is a mixture of one or more selected from lead salts and stannous salts, the lead salts include lead halide, lead acetate and lead formate, and the stannous salts include stannous halide, stannous acetate and stannous formate; the solvent of the perovskite precursor solution is a mixture of one or more selected from dimethyl sulfoxide, formamide, butyrolactone and methylpyrrolidone; the molar ratio of the solute of the perovskite precursor solution to the methylamine halide is 0.5 to 5:1 (preferably 0.5 to 2:1).

[0038] Optimally, the perovskite precursor solution is subjected to a sizing treatment during coating; the coating method is spin coating, spray coating, blade coating or printing. The present invention uses the spin coating method as an example: a perovskite precursor solution containing a mixed amine halide is coated on a substrate to prepare a perovskite light-emitting layer. During the preparation process, the sizing speed is 1000-6000 rpm / min, the sizing time is 0.5-3 minutes, the anti-solvent is one or more of ethyl acetate, toluene, chlorobenzene, and chloroform, and the anti-solvent solution is added dropwise 30-36 seconds after the start of sizing. After that, the substrate coated with the perovskite is heated at 80-110°C for 5-10 minutes.

[0039] Optimally, the thickness of the perovskite light-emitting layer is 10 nm-100 μm (preferably 50-500 nm).

[0040] Optimally, the laser beam has a wavelength of 0.3-20 μm, an average power of 0.1-100 W, a pulse width of 1-500 ns, a laser frequency of 1-1000 kHz, a focused spot diameter of 0.1-100 μm, and a spot movement speed of 0.01-20 mm / s. The distance between the perovskite light-emitting layer and the laser beam source is 1-100 cm. The pattern resolution can be adjusted by varying the laser focused spot diameter, resulting in a micro-nano perovskite photoactive pattern with a resolution range of 300-5000 PPI.

[0041] The micro-perovskite light-emitting unit is used to make a light-emitting diode. The light-emitting diode comprises an indium tin oxide substrate, a hole injection layer, a hole transport layer, a perovskite layer, an electron transport layer, and a metal electrode, which are stacked in sequence. The perovskite layer is the micro-perovskite light-emitting unit and can be prepared using conventional methods.

[0042] The preferred embodiments of the present invention are described in detail below.

[0043] Example 1

[0044] This embodiment provides a micro perovskite light emitting unit and a preparation method thereof, comprising the following steps (eg Figure 1 shown):

[0045] (a) Substrate preparation (substrate a): Indium tin oxide glass was ultrasonically cleaned with deionized water, acetone, and isopropyl alcohol, followed by drying and UV-ozone cleaning for 15 minutes before use.

[0046] Prepare the perovskite precursor solution: Take 0.3 mmol of methylammonium bromide, 0.12 mmol of phenylethylammonium bromide, and 0.3 mmol of lead bromide in 1 mL of dimethyl sulfoxide and stir for 6 hours;

[0047] The perovskite precursor solution was spin-coated on the substrate a prepared above at a speed of 3500 rpm / min (see Figure 2 ), and 200 μL of toluene was added dropwise 35 seconds after the start of homogenization; then annealed at 90° C. for 5 minutes to obtain a perovskite light-emitting layer (i.e., a perovskite film b was obtained, Figure 2 );

[0048] (b) The prepared perovskite film was placed under a laser beam with a wavelength of 1.064 μm, a spot diameter of 10 μm, a power of 2 W, a moving speed of 0.1 mm / s, a laser pulse width of 90 ns, and a laser frequency of 20 kHz (with a spacing of 45 cm) for patterned etching to obtain a micro perovskite light-emitting unit. During the laser etching process, the perovskite is thermally decomposed into methylamine salts and vaporized to produce an optically inactive inorganic lead halide or stannous halide barrier layer c (see Figure 3 ).

[0049] Example 2

[0050] This embodiment provides a micro perovskite light-emitting unit and a preparation method thereof, which is basically the same as that in Example 1, except that the amount of methylamine bromide in the configured perovskite precursor solution is 0.1 mmol.

[0051] Example 3

[0052] This embodiment provides a micro perovskite light-emitting unit and a preparation method thereof, which is basically the same as that in Example 1, except that the amount of methylamine bromide in the configured perovskite precursor solution is 0.9 mmol.

[0053] Example 4

[0054] This embodiment provides a micro perovskite light-emitting unit and a preparation method thereof, which is basically the same as that in Example 1, except that the configured perovskite precursor solution does not contain phenylethylamine bromide.

[0055] Example 5

[0056] This embodiment provides a micro perovskite light-emitting unit and a preparation method thereof, which is basically the same as that in Example 1, except that: 0.09 mmol of methylamine bromide, 0.33 mmol of phenylethylamine bromide and 0.3 mmol of lead bromide are taken in 1 mL of dimethyl sulfoxide and stirred for 6 hours.

[0057] Example 6

[0058] This embodiment provides a micro perovskite light-emitting unit and a preparation method thereof, which is basically the same as that in Example 1, except that: 0.3 mmol of methylamine bromide, 0.12 mmol of phenylethylamine bromide and 0.3 mmol of lead bromide are taken in 6 mL of dimethyl sulfoxide and stirred for 6 hours.

[0059] Example 7

[0060] This embodiment provides a micro perovskite light-emitting unit and a preparation method thereof, which is basically the same as that in Example 1, except that: 0.45 mmol of methylamine bromide, 0.45 mmol of phenylethylamine bromide and 0.45 mmol of lead bromide are taken in 1 mL of dimethyl sulfoxide and stirred for 6 hours.

[0061] Example 8

[0062] This embodiment provides a micro perovskite light-emitting unit and a preparation method thereof, which is basically the same as that in Example 1, except that: in step (b), the prepared perovskite film is placed under a laser beam with a wavelength of 1.064 μm, a spot diameter of 10 μm, a power of 10 W, a laser pulse width of 100 ns, a moving speed of 0.01 mm / s, and a laser frequency of 1000 kHz (with a spacing of 20 cm) for patterned etching to obtain a micro perovskite light-emitting unit.

[0063] Comparative Example 1

[0064] This comparative example provides a method for preparing a non-halogenated methylamine type perovskite micro-light-emitting layer. The steps are basically the same as those in Example 1, except that the methylamine halide in the perovskite precursor solution is replaced by cesium halide. That is, the perovskite precursor solution used is: 0.3 mmol of cesium bromide, 0.12 mmol of phenylethylamine bromide, and 0.3 mmol of lead bromide are taken in 1 mL of dimethyl sulfoxide and stirred for 6 hours.

[0065] Comparative Example 2

[0066] This comparative example provides a method for preparing a non-halogenated methylamine type perovskite micro-light-emitting layer. The steps are basically the same as those in Example 1, except that the mixed amine halide in the perovskite precursor solution does not contain methylamine halide. That is, the perovskite precursor solution used is: 0.12 mmol of phenylethylamine bromide and 0.3 mmol of lead bromide are taken in 1 mL of dimethyl sulfoxide and stirred for 6 hours.

[0067] The micro perovskite light emitting cells prepared in Examples 1-9 and Comparative Examples 1-2 were tested, and the results are listed in Table 1 (supplementary test methods or standards).

[0068] Table 1 is the test data of the micro perovskite light-emitting units prepared in Examples 1-9 and Comparative Examples 1-2

[0069] Emission wavelength (nm) Pattern clarity Laser marking performance Example 1 532 Clear Excellent Example 2 506 generally good Example 3 527 Clear Excellent Example 4 535 Clear Excellent Example 5 496 Clear Excellent Example 6 531 Clear Excellent Example 7 510 Clear Excellent Example 8 532 Clear Excellent Comparative Example 1 523 Vague generally Comparative Example 2 / Vague Poor

[0070] From the data analysis of Examples 2-3 and Example 1 in Table 1, it can be seen that the concentration of methylammonium bromide has a great influence on the laser marking performance of the micro perovskite light-emitting unit. When its concentration is lower than 0.1 mmol / mL, the clarity of the micro perovskite light-emitting unit decreases; when its concentration increases to 0.9 mmol / mL, the clarity is not affected. Therefore, the concentration of methylammonium bromide can be changed within a certain range and a clear perovskite light-emitting unit pattern can still be obtained.

[0071] Comparison of Example 1 with Examples 4-5 shows that the absence of phenylethylamine bromide has no significant effect on the laser marking performance, while increasing the concentration of phenylethylamine bromide can cause the emission peak position to blue-shift.

[0072] By comparing Example 1 with Examples 6-7, it can be seen that when the concentration of the perovskite precursor solution is lower than 0.1 mmol / mL (0.05 mmol / mL) or higher than 0.3 mmol / mL (0.45 mmol / mL), the clarity of the micro perovskite light-emitting unit is not affected. The thickness of the perovskite film can be changed by precisely controlling the concentration of the perovskite precursor solution to obtain a clear perovskite light-emitting unit pattern.

[0073] By comparing Comparative Example 1 with Example 1, it can be seen that the laser marking performance of the cesium bromide-based perovskite is reduced, and it is difficult to obtain clear micro perovskite light-emitting units. Methylamine bromide is beneficial to improving the laser marking performance and obtaining clear micro perovskite light-emitting units.

[0074] By comparing Comparative Example 1 with Example 2, it can be seen that the fluorescence emission peak of the perovskite film based on pure phenylethylamine bromide (without the participation of methylamine bromide) cannot be directly observed, and it is difficult to obtain a clear micro-perovskite light-emitting unit. Methylamine bromide is beneficial to promote the emission of the fluorescence peak of the perovskite and obtain a clear micro-perovskite light-emitting unit.

[0075] The micro perovskite light-emitting unit in Example 1 was also made into a light-emitting diode, specifically: poly (3,4-ethylenedioxythiophene) polystyrene sulfonate and polyvinyl carbazole were coated on the surface of indium tin oxide glass, that is, 100 μl of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate was taken and spin-coated on the indium tin oxide glass at a speed of 4000 rpm / min, and then annealed at 150 ° C for 25 minutes and cooled to room temperature to obtain a hole injection layer; then 10 mg / ml polyvinyl carbazole chlorobenzene solution was spin-coated on the hole injection layer at a speed of 4000 rpm / min, and annealed at 130 ° C for 20 minutes to obtain a hole transport layer; a micro perovskite light-emitting unit layer was formed on the surface of the hole transport layer according to the aforementioned embodiments or comparative examples, and then an electron transport layer and a metal electrode were prepared in sequence: the micro perovskite light-emitting unit was placed in a thermal evaporation device and 55 nm was sequentially evaporated. 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene) (as an electron transport layer), 1nm lithium fluoride and 150nm aluminum electrode (lithium fluoride is the electrode modification layer and the aluminum electrode is the metal electrode) are used to prepare a light-emitting diode. Its structure is as follows Figure 4 shown.

[0076] Table 2 is a table showing the test data of the micro perovskite light-emitting units made into light-emitting diodes in the examples and comparative examples.

[0077]

[0078] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a micro perovskite light-emitting unit, characterized in that: The following steps are involved: (a) coating a perovskite precursor solution containing a mixed amine halide on a substrate, and forming a perovskite light-emitting layer through heat treatment; the mixed amine halide contains at least methylamine halide; (b) Patterning the perovskite light-emitting layer using a laser beam to obtain a micro perovskite light-emitting unit.

2. The method for preparing a micro perovskite light-emitting unit according to claim 1, wherein: The mixed amine halide further comprises a mixture of one or more of ethylamine halide, formamidine halide, dimethylamine halide, propylamine halide, butylamine halide, benzylamine halide, phenylethylamine halide, naphthylmethylamine halide and naphthylethylamine halide.

3. The method for preparing a micro perovskite light-emitting unit according to claim 2, wherein: The molar proportion of the methylamine halide in the mixed amine halide is 5%-100%.

4. The method for preparing a micro perovskite light-emitting unit according to claim 1, wherein: The methylamine halide is a mixture of one or more selected from the group consisting of ammonium chloride, ammonium bromide and ammonium iodide, and its concentration in the perovskite precursor solution is 0.05-5.0 mol / L.

5. The method for preparing a micro perovskite light-emitting unit according to claim 1, wherein: The solute of the perovskite precursor solution is a mixture of one or more selected from lead salts and stannous salts, wherein the lead salts include lead halide, lead acetate and lead formate, and the stannous salts include stannous halide, stannous acetate and stannous formate.

6. The method for preparing a micro perovskite light-emitting unit according to claim 5, characterized in that: The solvent of the perovskite precursor solution is a mixture of one or more selected from dimethyl sulfoxide, formamide, butyrolactone and methyl pyrrolidone.

7. The method for preparing a micro perovskite light-emitting unit according to claim 5, characterized in that: The molar ratio of the solute in the perovskite precursor solution to the methylamine halide is 0.5-5:

1.

8. The method for preparing a micro perovskite light-emitting unit according to claim 1, wherein: The heat treatment is performed at 80-110° C. for 5-10 minutes.

9. The method for preparing a micro perovskite light-emitting unit according to claim 8, characterized in that: The perovskite precursor solution is subjected to a homogenization treatment during coating.

10. The method for preparing a micro perovskite light-emitting unit according to claim 9, characterized in that: During the homogenization process, an anti-solvent is added dropwise. The anti-solvent is one or a mixture of several selected from ethyl acetate, toluene, chlorobenzene and chloroform.

11. The method for preparing a micro perovskite light-emitting unit according to claim 1, wherein: The thickness of the perovskite light-emitting layer is 10 nm-100 μm.

12. The method for preparing a micro perovskite light-emitting unit according to claim 1, wherein: The laser beam has a wavelength of 0.3-20 μm, an average power of 0.1-100 W, a pulse width of 1-500 ns, a laser frequency of 1-1000 kHz, a focused spot diameter of 0.1-100 μm, and a spot moving speed of 0.01-20 mm / s.

13. The method for preparing a micro perovskite light-emitting unit according to claim 12, wherein: The distance between the perovskite light-emitting layer and the laser beam light source is 1-100 cm.

14. A micro perovskite light-emitting unit, characterized in that: The invention is prepared by the preparation method described in any one of claims 1 to 13.

15. The micro perovskite light-emitting unit according to claim 14, characterized in that: Its resolution is 300-5000PPI.

16. Use of the micro perovskite light-emitting unit according to claim 14 or 15, characterized in that: It is used to make light-emitting diodes.

17. The use of the micro perovskite light-emitting unit according to claim 16, characterized in that: The light-emitting diode includes an indium tin oxide substrate, a hole injection layer, a hole transport layer, a perovskite layer, an electron transport layer and a metal electrode which are stacked in sequence, and the perovskite layer is the micro perovskite light-emitting unit.

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