A polarized micro LED device with adjustable emission color and its fabrication method

Abstract

The application discloses a polarization LED device with adjustable light-emitting color and a preparation method thereof. The preparation method comprises the following steps: mixing cesium oleate, erbium oleate, indium acetate, bismuth acetate, silver acetate, benzoyl chloride, dioctyl ether, oleic acid and oleylamine in proportion, then heating to 120-170 DEG C under a nitrogen atmosphere, reacting for 1-5 min, and stopping the reaction; adding a mixed solution of cyclohexane and ethyl acetate into the reaction solution, centrifuging, collecting the precipitate, repeating the operation, obtaining quantum dots, dispersing the quantum dots in cyclohexane to obtain a quantum dot solution; mixing the quantum dot solution with an inorganic polysilazane solution, ultrasonic dispersing, then heating the mixed solution to 70-90 DEG C, stirring and reacting for 10-15 h, so that the inorganic polysilazane is hydrolyzed to form a dense silicon oxide shell, and a slurry is obtained; preparing the slurry into a film, attaching the film to an LED device, and the polarization LED device with adjustable light-emitting color is obtained. The doping concentration is controlled by introducing a bait ion into a double perovskite system and utilizing energy transfer to realize light-emitting color.

Description

Technical Field

[0001] This invention belongs to the field of perovskite quantum dot material modification technology, and in particular relates to a polarized LED device with adjustable emission color and its preparation method. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Linearly polarized light emission is a special type of light emission phenomenon where the oscillation direction lies within a single plane. Compared to randomly polarized light, linearly polarized light possesses higher intensity, stronger penetration, and better directionality, thus finding wide applications in optical communication, laser technology, and biomedical imaging. Methods for realizing polarized lasers include introducing polarization selection elements into the resonator, such as Brewster plates, axons, or using uniaxial crystals and specific fabrication directions. However, these processes are quite complex and unsuitable for micro / nano devices. In recent years, with the development of micro / nano technology, the development of polarized micro / nano light sources has gradually become a research hotspot. However, this field also faces many challenges. Among them, the epitaxial growth control of nano / micro materials and the precise wavelength tuning are two major technical difficulties. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a polarized LED device with adjustable emission color and its preparation method. By introducing erbium ions into a double perovskite system and using energy transfer to control the emission color through doping concentration, a quantum dot solution is mixed with an inorganic polysilazane solution to control the generation of silicon oxide and spin-coating it into a film, thereby preparing a polarized micro / nano light source for use in the device.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] In a first aspect, the present invention provides a method for fabricating a polarized LED device with adjustable emission color, comprising the following steps:

[0007] Cesium oleate, erbium oleate, indium acetate, bismuth acetate, silver acetate, benzoyl chloride, dioctyl ether, oleic acid and oleylamine are mixed in proportion and heated to 120-170℃ under a nitrogen atmosphere. The reaction is carried out for 1-5 minutes and then stopped.

[0008] Add a mixture of cyclohexane and ethyl acetate to the reaction solution, centrifuge, collect the precipitate, repeat the operation to obtain quantum dots, disperse the quantum dots in cyclohexane to obtain a quantum dot solution;

[0009] Quantum dot solution is mixed with inorganic polysilazane solution and ultrasonically dispersed. Then the mixture is heated to 70-90℃ and stirred for 10-15 hours to hydrolyze the inorganic polysilazane to form a dense silicon oxide shell, thus obtaining a slurry.

[0010] The slurry is prepared into a film, which is then attached to an LED device to obtain the final product.

[0011] The inventors tried using octadecene as a reaction solvent, as its low polarity and high boiling point are beneficial for promoting quantum dot growth. However, they found that when octadecene was used as a reaction solvent, the octadecene double bonds were prone to polymerization at high temperatures, which was not conducive to the uniform synthesis of quantum dots and reduced the quantum yield. Using dioctyl ether as a reaction solvent, the effects of double bond polymerization caused by octadecene could be avoided, which was beneficial for improving the quality of quantum dots.

[0012] This invention utilizes the energy transfer principle of double perovskites, and by changing the doping ratio of erbium ions, the emission color can be adjusted.

[0013] In the preparation process, the erbium oleate precursor is synthesized first, which can reduce crystal defects and improve reaction efficiency.

[0014] In some embodiments, the molar ratio of cesium oleate, erbium oleate, indium acetate, bismuth acetate, silver acetate, benzoyl chloride, dioctyl ether, oleic acid, and oleylamine is 1.5-2.5:0.03-0.06:0.5-1:0.01-0.02:1:10-15:60-65:30-40:10-15;

[0015] The preferred ratio is 2.00:0.05:0.90:0.0125:1:13:62.95:31.54:10.99.

[0016] In some embodiments, the erbium oleate is prepared by mixing erbium acetate hydrate and oleic acid in a certain proportion and heating in a nitrogen atmosphere to obtain erbium oleate.

[0017] Preferably, the heating temperature in a nitrogen atmosphere is 100-140℃, and the holding time is 15-25 min. More preferably, the temperature is 110-130℃, and the holding time is 20 min.

[0018] In some embodiments, the method for preparing cesium oleate is as follows: cesium carbonate and oleic acid are mixed in a certain proportion and then heated under a nitrogen atmosphere to obtain cesium oleate.

[0019] Preferably, the heating temperature in a nitrogen atmosphere is 140-160℃, and the holding time is 15-25 min. More preferably, the temperature is 150℃, and the holding time is 20 min.

[0020] In some embodiments, cesium oleate, erbium oleate, indium acetate, bismuth acetate, silver acetate, benzoyl chloride, dioctyl ether, oleic acid and oleylamine are mixed in proportion, and then heated to 130-150°C under a nitrogen atmosphere, and the reaction is stopped after 1-3 minutes.

[0021] Preferably, the temperature is raised to 140°C and the reaction is carried out for 2 minutes under a nitrogen atmosphere.

[0022] Preferably, the reaction is stopped by cooling with ice water to lower the temperature.

[0023] In some embodiments, the volume ratio of cyclohexane to ethyl acetate in the mixed solution of cyclohexane and ethyl acetate is 2-5:1.

[0024] Preferably, in the mixed solution of cyclohexane and ethyl acetate, the volume ratio of cyclohexane to ethyl acetate is 2-4:1.

[0025] More preferably, in the mixed solution of cyclohexane and ethyl acetate, the volume ratio of cyclohexane to ethyl acetate is 3:1. This mixed solution of cyclohexane and ethyl acetate allows quantum dots to precipitate from a highly polar solvent, facilitating the centrifugation process to obtain the precipitated quantum dots.

[0026] In some embodiments, the inorganic polysilazane solution has a mass percentage of 15-25 wt%, and the quantum dot solution has a concentration of 0.004-0.01 mmol / L.

[0027] Preferably, the volume ratio of inorganic polysilazane solution to quantum dot solution is 3-5:1. After mixing, the mixture is sonicated for 2-5 minutes to remove excess oleic acid and oleamine from the surface and to allow the NH bonds of inorganic polysilazane to fully react with the perovskite surface.

[0028] In some embodiments, the quantum dot solution is mixed with an inorganic polysilazane solution, ultrasonically dispersed, and then the mixture is heated to 75-85°C and stirred for 12-13 hours.

[0029] Preferably, the quantum dot solution is mixed with the inorganic polysilazane solution, ultrasonically dispersed, and then the mixture is heated to 80°C and stirred for 12-13 hours.

[0030] In some embodiments, the LED device is an LED micro / nano chip with an excitation wavelength of 385nm.

[0031] In some embodiments, the method for preparing the slurry into a film is as follows: the colloidal solution is dropped onto a glass slide, and the film-forming solution is uniformly coated onto the substrate using a doctor blade.

[0032] In some embodiments, the method of attaching the film to the LED device is as follows: a colloidal solution is dropped onto the LED microchip, and a doctor blade is used to evenly spread the film-forming solution.

[0033] Secondly, the present invention provides a polarized LED device with adjustable emission color, which is prepared by the aforementioned preparation method.

[0034] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:

[0035] This invention provides a method for fabricating a polarized LED device with adjustable emission color, opening up new avenues for the development of tunable LED color and linearly polarized micro / nano light sources. It utilizes metal halide perovskite quantum dots Cs₂AgIn. 0.98 Bi 0.02 The design of Cl6 and a series of quantum dots doped with erbium ions at different concentrations allows the energy of the original self-limited emission state to be transferred to the erbium ion energy level. Thus, by adjusting the erbium ion doping concentration, the energy transfer efficiency can be changed, thereby altering the emission color of the fabricated LED optical device. Furthermore, due to the self-limited state distortion, lattice asymmetry, and self-assembly effect of double perovskites, the erbium ion-doped quantum dots exhibit polarized emission characteristics. The quantum dot solution can be mixed with an inorganic polysilazane solution to control the generation of silicon oxide and spin-coat it into a film, thus preparing a highly stable, highly polarized micro / nano light source for use in devices. This can also be used as a polarized micro / nano light source for the development of optical devices. Attached Figure Description

[0036] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0037] Figure 1 The Cs2AgIn described in Examples 1-4 of this invention 0.98 Bi 0.02 Cl6 and Er: Cs2AgIn 0.98 Bi 0.02 Transmission electron microscopy image of Cl6 quantum dots.

[0038] Figure 2 The Cs2AgIn described in Examples 1-4 of this invention 0.98 Bi 0.02 Cl6 and Er: Cs2AgIn 0.98 Bi 0.02 Powder X-ray diffraction pattern of Cl6 quantum dots.

[0039] Figure 3 The Cs2AgIn described in Examples 1-4 of this invention 0.98 Bi 0.02 Cl6 and Er: Cs2AgIn 0.98 Bi 0.02Photoluminescence and absorption spectra of Cl6 quantum dots.

[0040] Figure 4 The Cs2AgIn described in Examples 1-4 of this invention 0.98 Bi 0.02 Cl6 and Er: Cs2AgIn 0.98 Bi 0.02 Photoluminescence CIE spectra of Cl6 quantum dots.

[0041] Figure 5 The Cs2AgIn described in Examples 1-4 of this invention 0.98 Bi 0.02 Cl6 and Er: Cs2AgIn 0.98 Bi 0.02 Photoluminescence spectra of Cl6 quantum dots at different angles.

[0042] Figure 6 The Cs2AgIn described in Embodiments 5-8 of this invention 0.98 Bi 0.02 Normalized intensity spectra of Cl6 quantum dots at different angles.

[0043] Figure 7 The Cs2AgIn described in embodiments 9 and 10 of this invention 0.98 Bi 0.02 Cl6 and Er: Cs2AgIn 0.98 Bi 0.02 LED photoluminescence spectra and CIE spectra of Cl6 quantum dots at different angles. Detailed Implementation

[0044] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0045] The present invention will be further described below with reference to the embodiments.

[0046] Example 1:

[0047] (1) Preparation of precursor solution

[0048] 1623 mg of cesium carbonate and 20 ml of oleic acid were placed in a four-necked flask and allowed to stand for 20 min under a nitrogen atmosphere. The magnetic stirrer and heating device were then turned on, raising the temperature to 120 °C and holding it at that temperature for 30 min. After the reactants were completely dissolved, the temperature was raised to 150 °C and held for 20 min. After the solution obtained in the previous step cooled to room temperature, stirring was stopped, yielding the cesium oleate precursor solution.

[0049] 720 mg of erbium(III) acetate hydrate and 10 ml of oleic acid were placed in a four-necked flask and allowed to stand for 20 min under a nitrogen atmosphere. The magnetic stirring and heating device was then turned on to raise the temperature to 120 °C and then kept at that temperature for 30 min. After the reactants were completely dissolved, the temperature was raised to 150 °C and kept at that temperature for 20 min to obtain the erbium(III) oleic acid precursor solution.

[0050] (2) Lead-free double perovskite Cs2AgIn 0.98 Bi 0.02 Preparation of Cl6 quantum dots

[0051] 1.0 ml of cesium oleate solution, 0.2 mmol of indium acetate, 0.0025 mmol of bismuth acetate, 0.2 mmol of silver acetate, 0.3 ml of benzoyl chloride, 5.0 ml of dioctyl ether, 2.0 ml of oleic acid, and 0.5 ml of oleylamine were placed in a four-necked flask and allowed to stand for 20 minutes under a nitrogen atmosphere. Then, the magnetic stirring and heating device was turned on, and the mixture was heated to 100°C and maintained at this temperature for 1 hour.

[0052] After the reactants have completely dissolved, heat to 140°C, stop the reaction after 2 minutes, and cool with ice water.

[0053] Add cyclohexane and ethyl acetate in a volume ratio of 2:1 to the mixture, centrifuge at 8000 rpm for 8 min, discard the supernatant after precipitation; repeat the addition of reagents and centrifugation, discard the supernatant to obtain quantum dots, and disperse the quantum dots in 10 ml of cyclohexane.

[0054] Example 2:

[0055] The process is largely the same as in Example 1, except that in step 2), 1.0 ml of cesium oleate solution, 0.18 mmol of indium acetate, 0.0025 mmol of bismuth acetate, 0.2 mmol of silver acetate, 0.01 mmol of erbium oleate, 0.3 ml of benzoyl chloride, 5.0 ml of dioctyl ether, 2.0 ml of oleic acid, and 0.5 ml of oleylamine are placed in a four-necked flask, allowed to stand for 20 minutes under a nitrogen atmosphere, and then the magnetic stirring and heating device is turned on. The mixture is then heated to 100°C and maintained at this temperature for 1 hour.

[0056] Example 3:

[0057] The process is largely the same as in Example 1, except that in step 2), 1.0 ml of cesium oleate solution, 0.18 mmol of indium acetate, 0.0025 mmol of bismuth acetate, 0.2 mmol of silver acetate, 0.05 mmol of erbium oleate, 0.3 ml of benzoyl chloride, 5.0 ml of dioctyl ether, 2.0 ml of oleic acid, and 0.5 ml of oleylamine are placed in a four-necked flask, allowed to stand for 20 minutes under a nitrogen atmosphere, and then the magnetic stirring and heating device is turned on. The mixture is then heated to 100°C and maintained at this temperature for 1 hour.

[0058] Example 4:

[0059] The process is largely the same as in Example 1, except that in step 2), 1.0 ml of cesium oleate solution, 0.18 mmol of indium acetate, 0.0025 mmol of bismuth acetate, 0.2 mmol of silver acetate, 0.10 mmol of erbium oleate, 0.3 ml of benzoyl chloride, 5.0 ml of dioctyl ether, 2.0 ml of oleic acid, and 0.5 ml of oleylamine are placed in a four-necked flask, allowed to stand for 20 minutes under a nitrogen atmosphere, and then the magnetic stirring and heating device is turned on. The mixture is then heated to 100°C and maintained at this temperature for 1 hour.

[0060] Figure 1 Cs2AgIn as described in Examples 1-4 0.98 Bi 0.02 Cl6 and Er: Cs2AgIn 0.98 Bi 0.02 Transmission electron microscopy (TEM) images of Cl6 quantum dots, after statistical analysis and Gaussian fitting, show that the quantum dots have a size in the range of 12.74 ± 0.08 nm and exhibit high crystallinity.

[0061] Figure 2 Cs2AgIn as described in Examples 1-4 0.98 Bi 0.02 Cl6 and Er: Cs2AgIn 0.98 Bi 0.02 Powder X-ray diffraction pattern of Cl6 quantum dots. When erbium ions are doped into the quantum dots, the crystal structure of the perovskite matrix remains unchanged, and the quantum dots exhibit a cubic crystal structure. structure.

[0062] Figure 3 The Cs2AgIn described in Examples 1-4 of this invention 0.98 Bi 0.02 Cl6 and Er: Cs2AgIn 0.98 Bi 0.02 Photoluminescence and absorption spectra of Cl6 quantum dots. It can be clearly seen that Cs2Ag6In... 0.98 Bi 0.02The photoluminescence of Cl6 quantum dots exhibits a single broad emission band centered at 620 nm, with a maximum half-width (FWHM) of 179 nm. After erbium ion doping, the quantum dots show broad STEs emission at 533, 559, 657, and 808 nm, along with four sharp emission peaks, corresponding to Erbium ions. 3+ intrinsic 2 H 11 / 2 → 4 I 15 / 2 , 4 S 3 / 2 → 4 I 15 / 2 , 4 F 9 / 2 → 4 I 15 / 2 , and 4 I 9 / 2 → 4 I 15 / 2 Leap forward.

[0063] Figure 4 The Cs2AgIn described in Examples 1-4 of this invention 0.98 Bi 0.02 Cl6 and Er: Cs2AgIn 0.98 Bi 0.02 The photoluminescence CIE spectra of Cl6 quantum dots showed significant changes in CIE coordinates by altering the erbium ion doping content.

[0064] Figure 5 The Cs2AgIn described in Examples 1-4 of this invention 0.98 Bi 0.02 Cl6 and Er: Cs2AgIn 0.98 Bi 0.02 Photoluminescence spectra of Cl6 quantum dots at different angles.

[0065] Example 5:

[0066] The process was largely the same as in Example 1, except that in step 2), a 2:1 mixture of cyclohexane and ethyl acetate was added to the mixture, centrifuged at 8000 rpm for 8 min, and the supernatant was discarded after precipitation. The addition of the reagents and centrifugation were repeated, and the supernatant was discarded to obtain quantum dots. The quantum dots were then dispersed in 10 ml of cyclohexane. The solution was subsequently diluted to 0.004 mmol / L, and the polarization degree of the solution was 0.205.

[0067] Example 6:

[0068] The process was largely the same as in Example 1, except that in step 2), a 2:1 volume ratio of cyclohexane and ethyl acetate was added to the mixture, centrifuged at 8000 rpm for 8 min, and the supernatant was discarded after precipitation. The addition of the reagents and centrifugation were repeated, and the supernatant was discarded to obtain quantum dots. The quantum dots were then dispersed in 10 ml of cyclohexane. The solution was subsequently diluted to 0.003 mmol / L, and the degree of polarization was 0.214.

[0069] Example 7:

[0070] The process was largely the same as in Example 1, except that in step 2), a 2:1 (volume ratio) mixture of cyclohexane and ethyl acetate was added to the mixture, centrifuged at 8000 rpm for 8 min, and the supernatant was discarded after precipitation. The addition of the reagents and centrifugation were repeated, and the supernatant was discarded to obtain quantum dots. The quantum dots were then dispersed in 10 ml of cyclohexane. The solution was subsequently diluted to 0.002 mmol / L, and the degree of polarization was 0.238.

[0071] Example 8:

[0072] The process was largely the same as in Example 1, except that in step 2), a 2:1 mixture of cyclohexane and ethyl acetate was added to the mixture, centrifuged at 8000 rpm for 8 min, and the supernatant was discarded after precipitation. The addition of the reagents and centrifugation were repeated, and the supernatant was discarded to obtain quantum dots. The quantum dots were then dispersed in 10 ml of cyclohexane. The solution was subsequently diluted to 0.001 mmol / L, and the degree of polarization was 0.240.

[0073] Figure 6 Cs2AgIn from Examples 5-8 0.98 Bi 0.02 Normalized intensity spectra of Cl6 quantum dots at different angles show the influence of the spatial arrangement and degree of order between individual nanoparticles on the polarization degree.

[0074] Example 9:

[0075] (1) Preparation of precursor solution

[0076] 1623 mg of cesium carbonate and 20 ml of oleic acid were placed in a four-necked flask and allowed to stand for 20 min under a nitrogen atmosphere. The magnetic stirrer and heating device were then turned on, raising the temperature to 120 °C and holding it at that temperature for 30 min. After the reactants were completely dissolved, the temperature was raised to 150 °C and held for 20 min. After the solution obtained in the previous step cooled to room temperature, stirring was stopped, yielding the cesium oleate precursor solution.

[0077] 720 mg of erbium(III) acetate hydrate and 10 ml of oleic acid were placed in a four-necked flask and allowed to stand for 20 min under a nitrogen atmosphere. The magnetic stirring and heating device was then turned on to raise the temperature to 120 °C and then kept at that temperature for 30 min. After the reactants were completely dissolved, the temperature was raised to 150 °C and kept at that temperature for 20 min to obtain the erbium(III) oleic acid precursor solution.

[0078] (2) Lead-free double perovskite Cs2AgIn 0.98 Bi 0.02 Preparation of Cl6 quantum dots

[0079] 1.0 ml of cesium oleate solution, 0.2 mmol of indium acetate, 0.0025 mmol of bismuth acetate, 0.2 mmol of silver acetate, 0.3 ml of benzoyl chloride, 5.0 ml of dioctyl ether, 2.0 ml of oleic acid, and 0.5 ml of oleylamine were placed in a four-necked flask and allowed to stand for 20 minutes under a nitrogen atmosphere. Then, the magnetic stirring and heating device was turned on, and the mixture was heated to 100°C and maintained at this temperature for 1 hour.

[0080] After the reactants have completely dissolved, heat to 140°C, stop the reaction after 2 minutes, and cool with ice water.

[0081] Add a 2:1 mixture of cyclohexane and ethyl acetate to the mixture, centrifuge at 8000 rpm for 8 min, discard the supernatant after precipitation; repeat the addition of reagents and centrifugation, discard the supernatant to obtain quantum dots, and disperse the quantum dots in 10 ml of cyclohexane.

[0082] (3) To achieve passivation of double perovskite quantum dots by inorganic polysilazane.

[0083] The quantum dot solution was mixed with 20 wt% inorganic polysilazane solution at a volume ratio of 1:4. The mixture was then sonicated for 3 min to obtain a quantum dot solution passivated with inorganic polysilazane.

[0084] (4) To enable inorganic polysilazane to achieve a single-point approximation coating effect on double perovskite quantum dots.

[0085] The mixed solution was heated and stirred at 80°C for 12 hours to allow the inorganic polysilazane to fully hydrolyze and form a dense silica shell.

[0086] (5) Assemble the thin film with the LED chip, the LED chip emits wavelength of 390nm.

[0087] Example 10:

[0088] (1) Preparation of precursor solution

[0089] 1623 mg of cesium carbonate and 20 ml of oleic acid were placed in a four-necked flask and allowed to stand for 20 min under a nitrogen atmosphere. The magnetic stirrer and heating device were then turned on, raising the temperature to 120 °C and holding it at that temperature for 30 min. After the reactants were completely dissolved, the temperature was raised to 150 °C and held for 20 min. After the solution obtained in the previous step cooled to room temperature, stirring was stopped, yielding the cesium oleate precursor solution.

[0090] 720 mg of erbium(III) acetate hydrate and 10 ml of oleic acid were placed in a four-necked flask and allowed to stand for 20 min under a nitrogen atmosphere. The magnetic stirring and heating device was then turned on to raise the temperature to 120 °C and then kept at that temperature for 30 min. After the reactants were completely dissolved, the temperature was raised to 150 °C and kept at that temperature for 20 min to obtain the erbium(III) oleic acid precursor solution.

[0091] (2) Lead-free double perovskite Cs2AgIn 0.98 Bi 0.02 Preparation of Cl6 quantum dots

[0092] 1.0 ml of cesium oleate solution, 0.18 mmol of indium acetate, 0.0025 mmol of bismuth acetate, 0.2 mmol of silver acetate, 0.10 mmol of erbium oleate, 0.3 ml of benzoyl chloride, 5.0 ml of dioctyl ether, 2.0 ml of oleic acid, and 0.5 ml of oleylamine were placed in a four-necked flask and allowed to stand for 20 minutes under a nitrogen atmosphere. The magnetic stirrer and heating device were then turned on, and the mixture was heated to 100°C and maintained at this temperature for 1 hour.

[0093] After the reactants have completely dissolved, heat to 140°C, stop the reaction after 2 minutes, and cool with ice water.

[0094] Add a 2:1 mixture of cyclohexane and ethyl acetate to the mixture, centrifuge at 8000 rpm for 8 min, discard the supernatant after precipitation; repeat the addition of the mixed reagents and centrifugation, discard the supernatant to obtain quantum dots, and disperse the quantum dots in 10 ml of cyclohexane.

[0095] (3) To achieve passivation of double perovskite quantum dots by inorganic polysilazane.

[0096] The quantum dot solution was mixed with 20 wt% inorganic polysilazane solution at a volume ratio of 4:1. The mixture was then sonicated for 3 min to obtain a quantum dot solution passivated with inorganic polysilazane.

[0097] (4) To enable inorganic polysilazane to achieve a single-point approximation coating effect on double perovskite quantum dots.

[0098] The mixed solution was heated and stirred at 80°C for 12 hours to allow the inorganic polysilazane to fully hydrolyze and form a dense silica shell.

[0099] (5) Assemble the thin film with the LED chip, the LED chip emits wavelength of 385nm.

[0100] Figure 7 The Cs2AgIn described in Examples 9 and 10 0.98 Bi 0.02 Cl6 and Er: Cs2AgIn 0.98 Bi 0.02 LED photoluminescence spectra and CIE spectra of Cl6 quantum dots at different angles, Cs2AgIn 0.98 Bi 0.02 LED light emission pattern prepared with Cl6 is shown below. Figure 7 As shown in Figure a, as the polarization angle increases, the emission peak gradually red-shifts, and after reaching 90°, when the polarization angle increases, the emission peak shifts blue. Figure 7 The CIE coordinates of b in the middle also prove this experimental result; Er: Cs2AgIn 0.98 Bi 0.02 LED light emission pattern prepared with Cl6 is shown below. Figure 7 As shown in Figure c, as the polarization angle increases, the emission peak gradually red-shifts, and after reaching 90°, when the polarization angle increases, the emission peak shifts blue. Figure 7 The CIE coordinates of d in the middle also prove this experimental result.

[0101] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of fabricating a tunable color emitting polarized LED device, comprising: The method comprises the following steps: ​ The cesium oleate, erbium oleate, indium acetate, bismuth acetate, silver acetate, benzoyl chloride, dicaprylyl ether, oleic acid and oleylamine are mixed in a molar ratio of 1.5-2.5:0.03-0.06:0.5-1:0.01-0.02:1:10-15:60-65:30-40:10-15, and then heated to 120-170℃ under a nitrogen atmosphere, and the reaction is stopped after 1-5 min; A mixed solution of cyclohexane and ethyl acetate is added to the reaction solution, and the precipitate is collected by centrifugation, and the operation is repeated to obtain quantum dots, and the quantum dots are dispersed in cyclohexane to obtain a quantum dot solution; The quantum dot solution is mixed with an inorganic polysilazane solution, ultrasonic dispersion is performed, and then the mixed solution is heated to 70-90℃, and the reaction is stirred for 10-15 h to hydrolyze the inorganic polysilazane to form a dense silica shell, thereby obtaining a slurry; The slurry is prepared into a film, and the film is attached to an LED device, thereby obtaining the product.

2. The method for preparing a polarized LED device with adjustable emission color according to claim 1, characterized in that: The preparation method of the erbium oleate is as follows: the erbium acetate hydrate and the oleic acid are mixed in a certain proportion, and then heated under a nitrogen atmosphere to obtain the erbium oleate.

3. The method for preparing a polarized LED device with adjustable emission color according to claim 2, characterized in that: The heating temperature under the nitrogen atmosphere is 100-140℃, and the holding time is 15-25 min.

4. The method for preparing a polarized LED device with adjustable emission color according to claim 1, characterized in that: The preparation method of the cesium oleate is as follows: the cesium carbonate and the oleic acid are mixed in a certain proportion, and then heated under a nitrogen atmosphere to obtain the cesium oleate.

5. The method for preparing a polarized LED device with adjustable emission color according to claim 4, characterized in that: The heating temperature under the nitrogen atmosphere is 140-160℃, and the holding time is 15-25 min.

6. The method of claim 1, wherein: The cesium oleate, erbium oleate, indium acetate, bismuth acetate, silver acetate, benzoyl chloride, dicaprylyl ether, oleic acid and oleylamine are mixed in a certain proportion, and then heated to 130-150℃ under a nitrogen atmosphere, and the reaction is stopped after 1-3 min.

7. The method for preparing a polarized LED device with adjustable emission color according to claim 6, characterized in that: The temperature is increased to 140℃ under a nitrogen atmosphere, and the reaction is performed for 2 min.

8. The method for preparing a polarized LED device with adjustable emission color according to claim 6, characterized in that: After the reaction is stopped, ice water is used for cooling to reduce the temperature and stop the reaction.

9. The method of claim 1, wherein: In the mixed solution of cyclohexane and ethyl acetate, the volume ratio of cyclohexane to ethyl acetate is 2-5:

1.

10. The method for preparing a polarized LED device with adjustable emission color according to claim 9, characterized in that: In the mixed solution of cyclohexane and ethyl acetate, the volume ratio of cyclohexane to ethyl acetate is 2-4:

1.

11. The method for preparing a polarized LED device with adjustable emission color according to claim 10, characterized in that: In the mixed solution of cyclohexane and ethyl acetate, the volume ratio of cyclohexane to ethyl acetate is 3:

1.

12. The method of claim 1, wherein: The mass percentage of the inorganic polysilazane solution is 15-25 wt%, and the concentration of the quantum dot solution is 0.004-0.01 mmol / L.

13. The method for preparing a polarized LED device with adjustable emission color according to claim 1, characterized in that: The volume ratio of the inorganic polysilazane solution to the quantum dot solution is 3-5:1, and ultrasonic dispersion is performed for 2-5 min after mixing.

14. The method of claim 1, wherein: The quantum dot solution is mixed with the inorganic polysilazane solution, ultrasonic dispersion is performed, and then the mixed solution is heated to 75-85℃, and the reaction is stirred for 12-13 h.

15. The method for preparing a polarized LED device with adjustable emission color according to claim 14, characterized in that: The quantum dot solution is mixed with the inorganic polysilazane solution, ultrasonic dispersion is performed, and then the mixed solution is heated to 80℃, and the reaction is stirred for 12-13 h.

16. The method of claim 1, wherein: The LED device is an excitation wavelength of 385 nm LED micro-nano chip.

17. The method for preparing a polarized LED device with adjustable emission color according to claim 1, characterized in that: The method for preparing the film from the slurry is as follows: the colloidal solution is dropped on a glass sheet, and a scraper is used to uniformly coat the film-forming solution on the substrate.

18. The method of claim 1, wherein: The method for attaching the film to the LED device is as follows: the colloidal solution is dropped on the LED micro-chip, and a scraper is used to uniformly coat the film-forming solution.

19. A tunable color emitting polarized LED device, characterized by: The product is prepared by the preparation method of any one of claims 1-18.

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