Preparation method of fapbi3 perovskite quantum dot light-emitting material and preparation method of light-emitting device

Abstract

This invention discloses a method for preparing FAPbI3 perovskite quantum dot luminescent materials and a method for preparing luminescent devices, relating to the field of quantum dot luminescence technology. By adding an ionic liquid—(diethylamino)difluorosulfonium tetrafluoroborate—to the precursor of FAPbI3 perovskite quantum dots, the luminous brightness and luminous efficiency of near-infrared perovskite quantum dot luminescent diodes are improved. By adding a certain amount of (diethylamino)difluorosulfonium tetrafluoroborate as a short-chain ionic ligand to the first precursor to bind to the surface of the perovskite quantum dots, surface defects of the perovskite quantum dots are passivated, and nonradiative recombination and uncontrolled ripening of the quantum dots are suppressed, thus synthesizing a high-quantum-yield FAPbI3 perovskite quantum dot luminescent material. Furthermore, the short alkyl chain of (diethylamino)difluorosulfonium tetrafluoroborate enhances the charge injection capability of the quantum dots, enabling the FAPbI3 near-infrared perovskite quantum dot luminescent devices prepared based on this material to achieve both high luminous efficiency and high luminous brightness.

Description

Technical Field

[0001] This invention relates to the field of quantum dot luminescence technology, and in particular to a method for preparing FAPbI3 perovskite quantum dot luminescent materials and a method for preparing luminescent devices. Background Technology

[0002] Light-emitting diodes (LEDs), with their high luminous efficiency, high brightness, and excellent lifespan, are gradually replacing traditional lighting sources and profoundly driving the development of industries such as lighting, displays, bio-imaging, and optical communications. Currently, various materials are available for commercial LEDs, such as III-V semiconductor LEDs, organic light-emitting diodes (OLEDs), and quantum dot light-emitting diodes (QLEDs). Near-infrared light, with a spectral range of 700–2500 nm, has enormous application value and development potential in fields such as optical communications, biomedical imaging, and facial recognition. OLEDs have become the leader in the LED field due to their solution and vacuum deposition capabilities, large-area light emission, and flexibility. However, low thermal stability, low chemical stability, and high manufacturing costs under high brightness and high current density conditions severely limit the application of OLEDs. QLEDs based on traditional materials exhibit excellent high color rendering index (CRI), high stability, and high efficiency. However, core-shell quantum dots are difficult to mass-produce due to complex manufacturing processes and expensive raw materials. All these drawbacks hinder the progress of cost-effective multi-scenario electroluminescence applications. Finding promising electroluminescent materials is crucial for advancing near-infrared light emission technology.

[0003] FAPbI3 perovskite quantum dots, as a promising new semiconductor material, possess advantages such as low cost, spectral tunability, and high photoluminescence quantum yield (PLQYs), opening up broad application scenarios in optoelectronics. Currently, the highest external quantum efficiency (EQE) of green and red quantum dot LEDs exceeds 28%, comparable to traditional OLEDs and QLEDs. However, the luminous performance of FAPbI3 perovskite quantum dot LEDs emitting in the near-infrared band around 800 nm still lags behind that of green and red LEDs. Low brightness and poor device lifetime are serious obstacles to the commercialization of near-infrared perovskite quantum dot LEDs. Therefore, in promoting the commercial development of perovskite quantum dots, key considerations should be given to improving their luminous brightness and extending device lifespan.

[0004] Currently, the ligands relied upon in the thermal injection synthesis of FAPbI3 perovskite quantum dots are mainly traditional oleic acid and oleylamine. However, the long alkyl chains of these two ligands limit the electrical properties of the quantum dot materials, thereby suppressing their electroluminescence capabilities. Furthermore, their weak binding force to the perovskite quantum dot surface makes these traditional ligands prone to detaching from the perovskite surface during purification or film formation, leading to increased defect density and even phase transitions. This severely impacts the device's luminous efficiency, brightness, and operational stability.

[0005] Therefore, it is necessary to replace or partially replace the traditional oleic acid and oleylamine ligands by starting with the surface ligands of perovskite quantum dots, and to develop a method for preparing FAPbI3 perovskite quantum dot luminescent materials and luminescent devices to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to solve the above problems by designing a method for preparing FAPbI3 perovskite quantum dot luminescent materials and a method for preparing luminescent devices. By adding an ionic liquid—(diethylamino)difluorosulfonium tetrafluoroborate—to the FAPbI3 perovskite quantum dot precursor, the luminous brightness and luminous efficiency of near-infrared perovskite quantum dot luminescent diodes are improved.

[0007] The present invention achieves the above objectives through the following technical solutions:

[0008] The preparation method of FAPbI3 perovskite quantum dot luminescent material includes the following steps:

[0009] S1. Place 0.175g PbI2 and (diethylamino)difluorosulfonium tetrafluoroborate into a No. 1 three-necked flask, and add 10ml octadecene as a solvent. Add 1.3g formamidine acetate and 12ml oleic acid to a No. 2 three-necked flask.

[0010] S2. Heat the solutions in the No. 1 and No. 2 three-necked flasks to 120°C and evacuate them. Maintain this condition and stir for 2-4 hours. Then fill the two three-necked flasks with nitrogen and continue stirring.

[0011] S3. Reduce the temperature of the two flasks to 100°C and add oleic acid and oleylamine to the stirring three-necked flask No. 1. After the solids are completely dissolved, evacuate the vacuum again and switch back to the nitrogen environment after 1 minute.

[0012] S4. Reduce the temperature of the No. 1 three-necked flask to 80℃, and quickly inject 2.5ml of solution from the No. 2 three-necked flask into the No. 1 three-necked flask. After reacting for 30 seconds, cool the No. 1 three-necked flask in an ice bath to obtain a crude perovskite quantum dot solution.

[0013] S5. Add 24 ml of methyl acetate to the cooled crude perovskite quantum dot solution and centrifuge. After centrifugation, redisperse the precipitate in 3 ml of toluene.

[0014] S6. Add 2 ml of methyl acetate to the solution obtained in step S5 and centrifuge again, then redisperse the precipitate in 1.5 ml of n-octane.

[0015] S7. Centrifuge the solution obtained in step S6 at a low speed of 5000 rpm using a centrifuge, and filter the resulting supernatant to obtain FAPbI3 perovskite quantum dot luminescent material.

[0016] The chemical formula of (diethylamino)difluorosulfonium tetrafluoroborate is C4H 10 BF6NS has the following chemical structural formula:

[0017]

[0018] The dosage range of (diethylamino)difluorosulfonium tetrafluoroborate is 3-12 mg.

[0019] A quantum dot light-emitting device includes a substrate with an ITO positive electrode, a PEDOT:PSS:PFI hole transport layer, a PTAA hole injection layer, a perovskite quantum dot light-emitting layer, a TPBi electron transport layer, a LiF electron transport layer, and an Al negative electrode, which are sequentially connected from one side to the other.

[0020] Methods for fabricating light-emitting devices include:

[0021] 1) Place the substrate with the ITO positive electrode printed in a mixed solution of anhydrous ethanol and deionized water, and sonicate it for 15 minutes with an ultrasonic machine, and then blow the liquid on its surface with nitrogen.

[0022] 2) Place the dried substrate with the ITO positive electrode printed on it into a UV cleaner and clean it with UV ozone for 15 minutes.

[0023] 3) Spin-coat a PEDOT:PSS:PFI film onto a clean substrate printed with an ITO positive electrode, and heat it at 150°C for 15 minutes using a hot plate.

[0024] 4) Place the product treated in step S3 into a glove box filled with nitrogen to spin coat a PTAA film and heat it at 160°C for 20 minutes;

[0025] 5) After the substrate treated by S4 has cooled down, spin-coat the PTAA film with the FAPbI3 perovskite quantum dot luminescent material as described above at a speed of 4000 rpm, and heat at 60°C for 5 minutes.

[0026] 6) Place the S5-treated product into the vapor deposition equipment and apply a vacuum. When the pressure is less than 5×10⁻⁶, -4 Light-emitting devices were obtained by evaporating TPBi, LiF and AL thin films at pa, with thicknesses of 100 nm, 1 nm and 100 nm respectively.

[0027] The beneficial effects of this invention are as follows:

[0028] (1) Add (diethylamino)difluorosulfonium tetrafluoroborate to the precursor to regulate the crystallization process of FAPbI3 perovskite quantum dots in situ, so that the size of the quantum dots is more uniform.

[0029] (2) The diethylamino group in (diethylamino)difluorosulfonium tetrafluoroborate can passivate the I group on the surface of perovskite quantum dots. - Ion binding inhibits halogen defect formation and ion migration, reducing nonradiative recombination;

[0030] (3) BF4 in (diethylamino)difluorosulfonium tetrafluoroborate - Anions can interact with uncoordinated Pb on the perovskite surface. 2+ Vacancy bonding passesivates defects generated during purification and film formation, thereby improving the luminescence quantum yield of perovskite quantum dots and the external quantum efficiency of the device.

[0031] (4) The short-chain (diethylamino)difluorosulfonium tetrafluoroborate can partially replace the traditional ligands to improve the current injection capability of perovskite quantum dots, thereby improving the brightness of light-emitting devices;

[0032] (4) The F element in (diethylamino)difluorosulfonium tetrafluoroborate has strong hydrophobicity, which makes the material more resistant to the erosion of moisture in the air, and is conducive to the light-emitting device to obtain better air stability and operational stability. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the FAPbI3 perovskite quantum dot light-emitting device in this invention;

[0034] Figure 2 The photoluminescence quantum yield (PLQYs) of FAPbI3 perovskite quantum dots with different amounts of (diethylamino)difluorosulfonium tetrafluoroborate added in this invention;

[0035] Figure 3 These are transmission electron microscope (TEM) images of Examples 1 and 4;

[0036] Where a is a TEM image of Example 1 and b is a TEM image of Example 4;

[0037] The attached diagram is labeled as follows:

[0038] 1-Substrate with ITO positive electrode printed on it, 2-PEDOT:PS:PFI hole transport layer, 3-PTAA hole injection layer, 4-Perovskite quantum dot light-emitting layer, 5-TPBi electron transport layer, 6-LiF electron transport layer, 7-Al negative electrode. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0041] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0042] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figure, or the orientation or positional relationship that the product of this invention is usually placed in when in use, or the orientation or positional relationship that is commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0043] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0044] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0046] The preparation method of FAPbI3 perovskite quantum dot luminescent material includes the following steps:

[0047] S1. Place 0.175g PbI2 and (diethylamino)difluorosulfonium tetrafluoroborate into a No. 1 three-necked flask, and add 10ml octadecene as a solvent. Add 1.3g formamidine acetate and 12ml oleic acid to a No. 2 three-necked flask.

[0048] S2. Heat the solutions in the No. 1 and No. 2 three-necked flasks to 120°C and evacuate them. Maintain this condition and stir for 2-4 hours. Then fill the two three-necked flasks with nitrogen and continue stirring.

[0049] S3. Reduce the temperature of the two flasks to 100°C and add oleic acid and oleylamine to the stirring three-necked flask No. 1. After the solids are completely dissolved, evacuate the vacuum again and switch back to the nitrogen environment after 1 minute.

[0050] S4. Reduce the temperature of the No. 1 three-necked flask to 80℃, and quickly inject 2.5ml of solution from the No. 2 three-necked flask into the No. 1 three-necked flask. After reacting for 30 seconds, cool the No. 1 three-necked flask in an ice bath to obtain a crude perovskite quantum dot solution.

[0051] S5. Add 24 ml of methyl acetate to the cooled crude perovskite quantum dot solution and centrifuge. After centrifugation, redisperse the precipitate in 3 ml of toluene.

[0052] S6. Add 2 ml of methyl acetate to the solution obtained in step S5 and centrifuge again, then redisperse the precipitate in 1.5 ml of n-octane.

[0053] S7. Centrifuge the solution obtained in step S6 at a low speed of 5000 rpm using a centrifuge, and filter the resulting supernatant to obtain FAPbI3 perovskite quantum dot luminescent material.

[0054] The chemical formula of (diethylamino)difluorosulfonium tetrafluoroborate is C4H 10 BF6NS has the following chemical structural formula: .

[0055] The dosage range of (diethylamino)difluorosulfonium tetrafluoroborate is 3-12 mg.

[0056] like Figure 1As shown, the quantum dot light-emitting device includes a substrate with an ITO positive electrode, a PEDOT:PSS:PFI hole transport layer, a PTAA hole injection layer, a perovskite quantum dot light-emitting layer, a TPBi electron transport layer, a LiF electron transport layer, and an Al negative electrode, which are sequentially connected from one side to the other.

[0057] Methods for fabricating light-emitting devices include:

[0058] 1) Place the substrate with the ITO positive electrode printed in a mixed solution of anhydrous ethanol and deionized water, and sonicate it for 15 minutes with an ultrasonic machine, and then blow the liquid on its surface with nitrogen.

[0059] 2) Place the dried substrate with the ITO positive electrode printed on it into a UV cleaner and clean it with UV ozone for 15 minutes.

[0060] 3) Spin-coat a PEDOT:PSS:PFI film onto a clean substrate printed with an ITO positive electrode, and heat it at 150°C for 15 minutes using a hot plate.

[0061] 4) Place the product treated in step 3) into a glove box filled with nitrogen to spin coat a PTAA film and heat it at 160°C for 20 minutes;

[0062] 5) After the substrate treated in 4) has cooled down, spin-coat the PTAA film with the FAPbI3 perovskite quantum dot luminescent material as described above at a speed of 4000 rpm, and heat at 60°C for 5 minutes.

[0063] 6) Place the product treated in step 5) into the vapor deposition equipment and apply a vacuum. When the pressure is less than 5 × 10⁻⁶, the vacuum level will be lower than 5 × 10⁻⁶. -4 Light-emitting devices were obtained by evaporating TPBi, LiF and AL thin films at pa, with thicknesses of 100 nm, 1 nm and 100 nm respectively.

[0064] Example 1 (Control Group):

[0065] (1) Synthesis and purification of quantum dot materials:

[0066] Prepare two 100ml three-necked glass flasks, clean them with deionized water and ethanol, dry them, and place clean magnetic stir bar inside. Add 0.175g PbI₂ to flask #1 and 10ml octadecene as precursor solution #1. Add 1.3g formamidine acetate and 12ml oleic acid to flask #2 as precursor solution #2. Heat both solutions to 120℃ and evacuate them under vacuum, maintaining this condition with stirring for 2 hours. Then, fill both flasks with nitrogen and immediately evacuate them again. Repeat this cycle three times. Adjust the heating temperature of both flasks to 100℃ and fill them with nitrogen. When flask #1 reaches 100℃, add 0.5ml oleic acid and 0.6ml oleylamine dropwise to the precursor solution using a syringe while continuously stirring. After the solid in the solution is completely dissolved, evacuate the clear solution in the flask for 2 minutes, then heat the solution to 80℃ under nitrogen atmosphere. At this point, 2.5 ml of precursor solution was drawn from precursor solution No. 2 and rapidly injected into flask No. 1. After reacting for 30 seconds, flask No. 1 was placed in pre-prepared ice water to cool. The cooled crude perovskite quantum dot solution was transferred to a centrifuge tube and 24 ml of methyl acetate was added. The mixture was centrifuged at 11,000 rpm for 1 min. Subsequently, the supernatant was discarded, and the precipitate obtained after centrifugation was redispersed in 3 ml of toluene solvent. 2 ml of methyl acetate was added to the above solution, and the mixture was centrifuged again at the same speed for 1 min. The supernatant was discarded, and the precipitate was dissolved in 1.5 ml of n-octane. After the precipitate was completely dispersed, it was centrifuged at a low speed of 5,000 rpm for 5 min to remove large particles. Finally, the supernatant obtained from the low-speed centrifugation was filtered through a 0.22-micron filter and placed in a clean glass bottle for sealing and storage.

[0067] (2) Fabrication of quantum dot light-emitting devices:

[0068] The ITO-printed glass substrate was ultrasonically cleaned with deionized water and anhydrous ethanol for 15 min each, and then treated with ultraviolet ozone for 15 min. Filtered PEDOT:PSS:PFI was then spin-coated onto the ITO substrate at 5000 rpm for 30 s as a hole transport layer and annealed at 150°C for 15 min. Next, PTAA was dissolved in chlorobenzene at a concentration of 5 mg / ml and spin-coated onto the PEDOT:PSS:PFI at 2000 rpm for 30 s as a hole injection layer, and annealed at 160°C for 20 min. FAPbI3 perovskite quantum dots were spin-coated onto the PTAA film at 4000 rpm as a light-emitting layer and annealed at 60°C for 5 min. Finally, the spin-coated substrate was transferred to a vapor deposition apparatus, where TPBi, LiF, and Al were sequentially deposited as electron transport layers and metal electrodes, with thicknesses of 100 nm, 1 nm, and 100 nm, respectively.

[0069] Example 2:

[0070] (1) Synthesis and purification of quantum dot materials:

[0071] Prepare two 100ml three-necked glass flasks, rinse them with deionized water and ethanol, dry them, and place clean magnetic stir bar inside. Add 0.175g PbI₂ and 3mg (diethylamino)difluorosulfonium tetrafluoroborate to flask No. 1, and add 10ml octadecene as the first precursor solution. Add 1.3g formamidine acetate and 12ml oleic acid to flask No. 2 as the second precursor solution. The remaining steps are the same as in Example 1.

[0072] (2) Fabrication of quantum dot light-emitting devices:

[0073] This part is exactly the same as in Example 1.

[0074] Example 3:

[0075] (1) Synthesis and purification of quantum dot materials:

[0076] Prepare two 100ml three-necked glass flasks, rinse them with deionized water and ethanol, dry them, and place clean magnetic stir bar inside. Add 0.175g PbI₂ and 6mg (diethylamino)difluorosulfonium tetrafluoroborate to flask No. 1, and add 10ml octadecene as precursor solution No. 1. Add 1.3g formamidine acetate and 12ml oleic acid to flask No. 2 as precursor solution No. 2. The remaining steps are the same as in Example 1.

[0077] (2) Fabrication of quantum dot light-emitting devices:

[0078] This part is the same as in Example 1.

[0079] Example 4:

[0080] (1) Synthesis and purification of quantum dot materials:

[0081] Prepare two 100ml three-necked glass flasks, rinse them with deionized water and ethanol, dry them, and place clean magnetic stir bar inside. Add 0.175g PbI₂ and 9mg (diethylamino)difluorosulfonium tetrafluoroborate to flask No. 1, and add 10ml octadecene as the first precursor solution. Add 1.3g formamidine acetate and 12ml oleic acid to flask No. 2 as the second precursor solution. The remaining steps are the same as in Example 1.

[0082] (2) Fabrication of quantum dot light-emitting devices:

[0083] This part is the same as in Example 1.

[0084] Example 5:

[0085] (1) Synthesis and purification of quantum dot materials:

[0086] Prepare two 100ml three-necked glass flasks, rinse them with deionized water and ethanol, dry them, and place clean magnetic stir bar inside. Add 0.175g PbI₂ and 12mg (diethylamino)difluorosulfonium tetrafluoroborate to flask No. 1, and add 10ml octadecene as the first precursor solution. Add 1.3g formamidine acetate and 12ml oleic acid to flask No. 2 as the second precursor solution. The remaining steps are the same as in Example 1.

[0087] (2) Fabrication of quantum dot light-emitting devices:

[0088] This part is the same as in Example 1.

[0089] Device performance and results analysis of the examples

[0090]

[0091] Table 1. Luminescent performance of perovskite quantum dot light-emitting devices

[0092] From Table 1 and Appendix Figure 2 It can be seen that with the increase of the amount of (diethylamino)difluorosulfonium tetrafluoroborate added (Examples 1-5), the brightness, external quantum efficiency, and photoluminescence quantum efficiency of the FAPbI3 perovskite quantum dot LED devices were significantly improved. Compared with the control group (Example 1), Example 4, which had the best luminous performance, showed a more than twofold increase in maximum brightness and efficiency. This is due to the diethylamino and BF4 groups in (diethylamino)difluorosulfonium tetrafluoroborate. - Anions inhibited defect formation in perovskite quantum dots and passivated residual surface defects, suppressing nonradiative recombination within the quantum dots. Simultaneously, the high conductivity of the short-chain (diethylamino)difluorosulfonium tetrafluoroborate enhanced the charge injection capability of the quantum dots. Through the synergistic effect of these multiple effects, the luminescence brightness and efficiency of the device were significantly improved. Furthermore, transmission electron microscopy images of the quantum dot material (attached) Figure 3We observed that, compared to the control group (Figure a), the size uniformity of the quantum dots in Example 4 (Figure b) was significantly improved. This is because (diethylamino)difluorosulfonium tetrafluoroborate suppressed defect formation and uncontrolled ripening of the quantum dots during in-situ synthesis and purification, resulting in more uniform size. Notably, as the amount of (diethylamino)difluorosulfonium tetrafluoroborate added continuously increased, the luminescence performance and PLQYs of the device decreased (Example 5). This is because the amino groups in (diethylamino)difluorosulfonium tetrafluoroborate affected the acid-base balance in the precursor solution, which to some extent affected the crystallization of perovskite quantum dots. Therefore, we controlled the amount of (diethylamino)difluorosulfonium tetrafluoroborate added to below 12 mg to obtain higher luminescence performance.

[0093] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing FAPbI3 perovskite quantum dot luminescent materials, characterized in that, Includes the following steps: S1. Place 0.175g PbI2 and (diethylamino)difluorosulfonium tetrafluoroborate into a No. 1 three-necked flask, and add 10ml octadecene as a solvent. Add 1.3g formamidine acetate and 12ml oleic acid to a No. 2 three-necked flask. S2. Heat the solutions in the No. 1 and No. 2 three-necked flasks to 120°C and evacuate them. Maintain this condition and stir for 2-4 hours. Then fill the two three-necked flasks with nitrogen and continue stirring. S3. Reduce the temperature of the two flasks to 100°C and add oleic acid and oleylamine to the stirring three-necked flask No.

1. After the solids are completely dissolved, evacuate the vacuum again and switch back to the nitrogen environment after 1 minute. S4. Reduce the temperature of the No. 1 three-necked flask to 80℃, and quickly inject 2.5ml of solution from the No. 2 three-necked flask into the No. 1 three-necked flask. After reacting for 30 seconds, cool the No. 1 three-necked flask in an ice bath to obtain a crude perovskite quantum dot solution. S5. Add 24 ml of methyl acetate to the cooled crude perovskite quantum dot solution and centrifuge. After centrifugation, redisperse the precipitate in 3 ml of toluene. S6. Add 2 ml of methyl acetate to the solution obtained in step S5 and centrifuge again, then redisperse the precipitate in 1.5 ml of n-octane. S7. Centrifuge the solution obtained in step S6 at a low speed of 5000 rpm using a centrifuge, and filter the resulting supernatant to obtain FAPbI3 perovskite quantum dot luminescent material.

2. The method for preparing FAPbI3 perovskite quantum dot luminescent material according to claim 1, characterized in that, The chemical formula of (diethylamino)difluorosulfonium tetrafluoroborate is C4H 10 BF6NS has the following chemical structural formula: .

3. The method for preparing FAPbI3 perovskite quantum dot luminescent material according to claim 1, characterized in that, The dosage range of (diethylamino)difluorosulfonium tetrafluoroborate is 3-12 mg.

4. A method for fabricating a light-emitting device, characterized in that, include: 1) Place the substrate with the ITO positive electrode printed in a mixed solution of anhydrous ethanol and deionized water, and sonicate it for 15 minutes with an ultrasonic machine, and then blow the liquid on its surface with nitrogen. 2) Place the dried substrate with the ITO positive electrode printed on it into a UV cleaner and clean it with UV ozone for 15 minutes. 3) Spin-coat a PEDOT:PSS:PFI film onto a clean substrate printed with an ITO positive electrode, and heat it at 150°C for 15 minutes using a hot plate. 4) Place the product treated in step 3) into a glove box filled with nitrogen to spin coat a PTAA film and heat it at 160°C for 20 minutes; 5) After the substrate treated in 4) has cooled, spin-coat the FAPbI3 perovskite quantum dot luminescent material as described in any one of claims 1-3 onto the PTAA film at a speed of 4000 rpm, and heat it at 60°C for 5 minutes. 6) Place the product treated in step 5) into the vapor deposition equipment and apply a vacuum. When the pressure is less than 5 × 10⁻⁶, the vacuum level will be lower than 5 × 10⁻⁶. -4 Light-emitting devices were obtained by evaporating TPBi, LiF and AL thin films at pa, with thicknesses of 100 nm, 1 nm and 100 nm respectively.

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