All-inorganic perovskite quantum dots / polyvinylidene fluoride ink for color conversion and preparation method and application thereof

Abstract

The application discloses a kind of full inorganic perovskite quantum dots / polyvinylidene fluoride inks for color conversion and preparation method and application thereof, and the weight percentage of each component in full inorganic perovskite quantum dots / polyvinylidene fluoride ink for color conversion is as follows: perovskite precursor 0.01-5%, polymer 0.5-40%, ligand 0.01-0.5%, diffusion powder 0.5-5%, dispersing agent 50-95%, and the sum of the weight percentage of each component is 100%. The application can be prepared by coating and inkjet printing method to obtain full inorganic perovskite quantum dots / polyvinylidene fluoride color conversion layer, and the stability and luminous efficiency of the inorganic perovskite quantum dots / polyvinylidene fluoride color conversion layer are significantly improved compared with quantum dot film prepared by traditional method, which can be used as color conversion layer in wide color gamut LED backlight display, flexible display, Mini / Micro-LED full-color display and other fields.

Description

Technical Field

[0001] This invention belongs to the field of nano-optoelectronic material preparation technology, and in particular relates to an all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion, its preparation method and application. Background Technology

[0002] Performance metrics for evaluating displays include contrast ratio, response time, refresh rate, resolution, and viewing angle. Among these, one of the most significant indicators affecting human visual perception is the panel's color gamut, a crucial measure of a display's ability to reproduce colors. Quantum dots possess numerous excellent optoelectronic properties, such as high color purity, tunable emission color, and high fluorescence quantum yield, making them a very important luminescent material that has attracted widespread attention in both display and lighting fields. They hold particular potential for improving the color gamut of display panels, and have been a focus of the display panel industry since their initial reports.

[0003] Color conversion applications are mainly based on the photoluminescence properties of quantum dot materials. They can be divided into incomplete color conversion and complete color conversion. The former is mainly used for the backlight of LCD displays. Under the excitation of blue LEDs, a white backlight source is obtained. Combined with the color filter film inside the LCD panel, full-color display is achieved. Complete color conversion uses blue OLED or blue Mini- / Micro-LED displays as the excitation source. Green and red quantum dot color conversion layers are integrated into the display panel. A color conversion strategy is adopted to obtain the required green and red light emission. Combined with the blue OLED or blue Mini- / Micro-LED itself, full-color display is achieved.

[0004] Perovskite materials have immense application potential in photonics and optoelectronics, and are currently undergoing industrialization. In particular, all-inorganic CsPbX3 (X = Cl, Br, or I) quantum dots with high quantum yields are promising due to their high optical efficiency, low cost, and high absorption coefficient (up to 10). 5 cm -1With its advantages such as large-scale (and in-situ preparation capabilities), perovskite quantum dots have become one of the important material systems for quantum dot color conversion applications. However, the poor stability of metal halide perovskite quantum dots severely restricts their application in color conversion devices. Although there are existing patents that utilize the in-situ preparation capability of perovskite quantum dots by mixing perovskite precursors with polymers and then evaporating to obtain highly stable perovskite quantum dot films (WO2016180364A1), this synthesis method only achieves good results for organic-inorganic hybrid perovskite polymer films. For all-inorganic perovskite quantum dot / polymer films, the synthesis is cumbersome, requires high synthesis temperatures, and results in films with uneven luminescence, low luminous efficiency, and poor stability. Therefore, the current methods for preparing high-quality all-inorganic perovskite / polyvinylidene fluoride inks still need improvement. Summary of the Invention

[0005] To address the shortcomings of the existing technologies, this invention proposes an all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion, its preparation method, and its applications. This invention solves the bottleneck problems of low luminous efficiency and uneven luminous emission in the all-inorganic perovskite quantum dot / polyvinylidene fluoride color conversion layer. The preparation method is simple, rapid, and uses widely available raw materials. It also produces an all-inorganic perovskite quantum dot / polyvinylidene fluoride color conversion layer with high luminous efficiency, uniform luminous emission, and good stability. Furthermore, it is suitable for industrial-scale production and has broad market application prospects in wide color gamut LED backlight displays, flexible displays, and Mini- / Micro-LED full-color displays.

[0006] To address the aforementioned technical problems, this invention provides an all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion, comprising a perovskite precursor, a polymer, ligands, a diffusing powder, and a dispersant, with the following weight percentages for each component:

[0007]

[0008] The sum of the weight percentages of all components is 100%.

[0009] Furthermore, the weight percentages of each component in the all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion are as follows:

[0010]

[0011] The sum of the weight percentages of all components is 100%.

[0012] Furthermore, the perovskite precursor is selected from CsX and DMAPbX3, where X is at least one of Cl, Br and I.

[0013] Furthermore, the molar ratio of CsX to DMAPbX3 is between 1:0.1 and 5, preferably between 1:0.5 and 2.

[0014] For example, the molar ratio of CsBr to DMAPbBr3 is 1:1; the molar ratio of DMAPbBr3 to DMAPbI3 is 5:1; and the molar ratio of DMAPbBr3 to DMAPbI3 is 1:1.

[0015] Furthermore, the polymer is selected from fluorinated polymers, such as polyvinylidene fluoride, wherein the average molecular weight of the polyvinylidene fluoride is between 180,000 and 1,000,000.

[0016] Furthermore, the ligand is selected from one or any mixture of several of ammonium halide salts, phosphonium halide salts, and sulfonium halide salts.

[0017] For example, tetrabutylammonium bromide, tetradecylammonium bromide, tetrabutylphosphonium bromide, tetraphenylphosphonium bromide, tributylhexylphosphonium bromide, trimethylsulfonium bromide, and triphenylsulfonium bromide.

[0018] Furthermore, the diffusing powder is selected from silica light diffusing agents and / or organic light diffusing agents.

[0019] Furthermore, the organic light diffusing agent is selected from one or more of acrylic, styrene, acrylic resin, and silicone types.

[0020] Furthermore, the dispersant is selected from organic strong polar solvents that have a strong coordination ability with the perovskite precursor and can dissolve polyvinylidene fluoride, including one or a mixture of two of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO).

[0021] Furthermore, the viscosity of the all-inorganic perovskite quantum dot / polyvinylidene fluoride ink at 25°C is between 500 and 10,000 cps.

[0022] This invention also provides an all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion and its preparation method, comprising the following steps:

[0023] 1) Add the prescribed amount of polymer and dispersant to the container, heat to 80-90℃ and stir with a high-speed stirrer for 10-30 minutes at a speed of 500-1000 rpm.

[0024] 2) Add the amount of perovskite precursor specified in the formula and stir with a high-speed stirrer for 5-10 minutes at a speed of 500-1000 rpm.

[0025] 3) Add the required amount of diffusion powder and ligand, stir at room temperature for 5-10 minutes at a speed of 800-1000 rpm, and you will get the all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion.

[0026] This invention also provides the application of all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion in liquid crystal displays, including:

[0027] 1) The inorganic perovskite quantum dot / polyvinylidene fluoride ink is uniformly coated on the substrate by coating methods (including: doctor blade, wire bar, slit, comma coating), and then the dispersant is evaporated at a certain temperature to obtain the inorganic perovskite quantum dot / polyvinylidene fluoride color conversion layer, which can be coated on the blue LED light guide plate for the backlight of the liquid crystal display.

[0028] Furthermore, the dispersant is evaporated at a temperature range of 10-90℃.

[0029] Furthermore, the substrate is selected from glass and polyethylene terephthalate film (PET).

[0030] This invention also provides the application of all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion in full-color displays of Mini- / Micro-LEDs, including:

[0031] All-inorganic perovskite quantum dot / polyvinylidene fluoride ink is printed onto the pixels of a Mini- / Micro-LED chip using inkjet printing technology. During this process, the dispersant evaporates quickly, resulting in an all-inorganic perovskite quantum dot / polyvinylidene fluoride color conversion layer for full-color display of Mini- / Micro-LEDs.

[0032] Furthermore, the all-inorganic perovskite quantum dot / polyvinylidene fluoride ink exhibits excellent stability and tunability, while the prepared color conversion layer possesses superior luminescent properties and spectral stability.

[0033] Furthermore, the aforementioned all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion and its preparation method are applied in fields such as wide color gamut LED backlight display, flexible display, and Mini / Micro-LED full-color display.

[0034] The beneficial effects of this invention are:

[0035] This invention provides an all-inorganic perovskite quantum dot / polyvinylidene fluoride (PVDF) ink for color conversion and its preparation method. By selecting a DMAPbX3 precursor with the same lead halide stoichiometry as the target CsPbX3 perovskite material, and utilizing an ion exchange reaction mechanism, the generation of halogen vacancy defects in the crystal structure during perovskite quantum dot preparation is significantly reduced. Furthermore, an organic halide salt ligand is introduced to provide an additional halogen environment, solving the problems of low luminous efficiency and poor film formation in all-inorganic perovskite quantum dot / polymer color conversion layers. This invention achieves high luminous efficiency and high stability in all-inorganic perovskite quantum dot / PVDF color conversion layers. Simultaneously, the preparation method is simple, convenient, and reproducible, suitable for large-scale industrial production, and compatible with various conventional coating and printing processes.

[0036] The all-inorganic perovskite quantum dot / polyvinylidene fluoride ink obtained by this invention exhibits excellent stability and tunability, while the prepared color conversion layer possesses superior luminescent properties and spectral stability. It can be used in lighting displays, as well as in solar cells, fluorescence sensing, photocatalysis or photoelectrocatalysis, and photodetectors. Attached Figure Description

[0037] Figure 1 The emission spectrum of the color conversion layer prepared in Example 1 of this invention is shown.

[0038] Figure 2 The emission spectrum of the color conversion layer prepared in Example 2 of this invention is shown.

[0039] Figure 3 The emission spectrum of the color conversion layer prepared in Example 3 of this invention is shown.

[0040] Figure 4 The emission spectrum of the color conversion layer prepared in Example 4 of this invention is shown.

[0041] Figure 5 The emission spectrum of the color conversion layer prepared in Example 5 of this invention is shown. Detailed Implementation Plan

[0042] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Various equivalent modifications and variations of the present invention by those skilled in the art fall within the scope defined by the appended claims.

[0043] Example 1

[0044] Add 600 mg of polyvinylidene fluoride (average relative molecular weight ~1,000,000), 4 mL of DMF dispersant, and 1 mL of DMSO dispersant to a container. Heat to 85°C and stir for 30 min at 500 rpm using a high-speed stirrer. Add 4.2 mg of CsBr and 9.0 mg of DMAPbBr3, and continue stirring for 5 min. Then add 100 mg of silica diffusion powder and 5 mg of tetrabutylphosphonium bromide ligand, and stir at room temperature for 10 min at 1000 rpm to obtain an all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion.

[0045] The ink was applied to the PET film using a doctor blade and dried at room temperature. After 30 minutes, a light green film was obtained.

[0046] like Figure 1 As shown, the emission spectrum of the color conversion layer is located in the range of 460-575 nm, with an emission peak at 513 nm, and its luminescence quantum yield is measured to be 49%.

[0047] Example 2

[0048] Add 600 mg of polyvinylidene fluoride (average relative molecular weight ~1,000,000), 4 mL of DMF dispersant, and 1 mL of DMSO dispersant to a container. Heat to 85°C and stir for 30 min at 500 rpm using a high-speed stirrer. Add 4.2 mg of CsBr and 9.0 mg of DMAPbBr3, and continue stirring for 5 min. Then add 100 mg of silica diffusion powder and 5 mg of tetrabutylphosphonium bromide ligand, and stir at room temperature for 10 min at 1000 rpm to obtain an all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion.

[0049] The ink was applied to the PET film using a doctor blade and placed in a 50°C forced-air drying oven. After 15 minutes, a green film was obtained.

[0050] like Figure 2 As shown, the emission spectrum of the color conversion layer is located at 455-575 nm, with an emission peak at 512 nm, and its luminescence quantum yield is measured to be 65%.

[0051] Example 3

[0052] Add 600 mg of polyvinylidene fluoride (average relative molecular weight ~1,000,000), 4 mL of DMF, and 1 mL of DMSO dispersant to a container, heat to 85°C, and stir for 30 min at 500 rpm using a high-speed stirrer. Add 4.2 mg of CsBr, 6.0 mg of DMAPbBr3, and 1.5 mg of DMAPbI3, and continue stirring for 5 min. Then add 100 mg of silica diffusion powder and 5 mg of tetrabutylphosphonium bromide ligand, and stir at room temperature for 10 min at 1000 rpm to obtain an all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion.

[0053] The ink was coated onto the PET film using a doctor blade and dried at room temperature. After 30 minutes, a yellow-green perovskite film was obtained.

[0054] like Figure 3 As shown, the emission spectrum of the color conversion layer is located in the range of 485-750 nm, with an emission peak at 584 nm, and its luminescence quantum yield is measured to be 27%.

[0055] Example 4

[0056] Add 600 mg of polyvinylidene fluoride (average relative molecular weight ~1,000,000), 4 mL of DMF, and 1 mL of DMSO dispersant to a container, heat to 85°C, and stir for 30 min at 500 rpm using a high-speed stirrer. Add 4.2 mg of CsBr, 4.5 mg of DMAPbBr3, and 5.9 mg of DMAPbI3, and continue stirring for 5 min. Then add 100 mg of silica diffusion powder and 5 mg of tetrabutylphosphonium bromide ligand, and stir at room temperature for 10 min at 1000 rpm to obtain an all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion.

[0057] The ink was applied to the PET film using a doctor blade and placed in a 50°C forced-air drying oven. After 15 minutes, a red film was obtained.

[0058] like Figure 4 As shown, the emission spectrum of the color conversion layer is located in the range of 510-780 nm, with an emission peak at 639 nm, and its luminescence quantum yield is measured to be 44%.

[0059] Example 5

[0060] Add 600 mg of polyvinylidene fluoride (average relative molecular weight ~1,000,000), 4 mL of DMF, and 1 mL of DMSO dispersant to a container. Heat to 85°C and stir for 30 min at 500 rpm using a high-speed stirrer. Add 4.2 mg of CsBr and 9.0 mg of DMAPbBr3, and continue stirring for 5 min. Then add 100 mg of silica diffusion powder and 5 mg of tetrabutylammonium bromide ligand, and stir at room temperature for 10 min at 1000 rpm to obtain an all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion.

[0061] The ink is printed onto a PET substrate using an inkjet printer to obtain a green perovskite film.

[0062] like Figure 5 As shown, the emission spectrum of the color conversion layer is located in the range of 480-580 nm, with a full width at half maximum (FWHM) of 524 nm. Its luminescence quantum yield is measured to be 52%.

[0063] All of the above operations are performed in an open environment, without the need for inert protective gas or strict dehydration and deoxygenation treatment.

[0064] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A color conversion ink made entirely of inorganic perovskite quantum dots / polyvinylidene fluoride, characterized in that, The ink contains a perovskite precursor, a polymer, ligands, a diffusing powder, and a dispersant, with the following weight percentages for each component: Perovskite precursor 0.01-5% Polymer 0.5-40% Ligand 0.01-0.5% Diffusion powder 0.5-5% Dispersant 50-95%; The sum of the weight percentages of all components is 100%. The perovskite precursor includes CsX and DMAPbX3, where X is at least one of Cl, Br and I; The molar ratio of CsX to DMAPbX3 is 1:0.1~5; The polymer is polyvinylidene fluoride, and the average molecular weight of polyvinylidene fluoride is between 180,000 and 1,000,000. The aforementioned all-inorganic perovskite quantum dot / polyvinylidene fluoride ink at 25 o The viscosity at C is between 500 and 10000 cps; The ligand is selected from one or any mixture of several of ammonium halide salts, phosphonium halide salts, and sulfonium halide salts.

2. The all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion according to claim 1, characterized in that, The weight percentages of each component are as follows: Perovskite precursor 0.1-2.5% Polymer 5-20% Ligand 0.05-0.2% Diffusion powder 0.5-2.5% Dispersant 80-90%; The sum of the weight percentages of all components is 100%.

3. The all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion according to claim 2, characterized in that, The molar ratio of CsX to DMAPbX3 is 1:0.5~2.

4. The all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion according to claim 2, characterized in that, The molar ratio of CsBr to DMAPbBr3 is 1:1; the molar ratio of DMAPbBr3 to DMAPbI3 is 5:

1.

5. The all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion according to claim 1, characterized in that, The ligand is tetrabutylammonium bromide, tetradecylammonium bromide, tetrabutylphosphonium bromide, tetraphenylphosphonium bromide, trimethylsulfonium bromide, or triphenylsulfonium bromide.

6. The all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion according to claim 1, characterized in that, The diffusing powder is selected from silica light diffusing agents and / or organic light diffusing agents.

7. The all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion according to claim 6, characterized in that, The organic light diffusing agent is selected from one or more of organosilicon, polystyrene, and acrylic resin light diffusing agents.

8. The all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion according to claim 1, characterized in that, The dispersant is N,N-dimethylformamide and / or dimethyl sulfoxide.

9. A method for preparing an all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion as described in any one of claims 1 to 8, characterized in that, Includes the following steps: a) Add the formulated amount of polymer and dispersant to a container and heat to 85°C. o C. Stir with a high-speed mixer for 10-30 minutes at a speed of 500-1000 rpm; b) Add the perovskite precursor according to the formula and stir with a high-speed stirrer for 5-10 minutes at a speed of 500-1000 rpm. c) Add the prescribed amount of diffusion powder and ligand, stir at room temperature for 5-10 minutes at a speed of 800-1000 rpm, and you will get an all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion.

10. The application of the color conversion all-inorganic perovskite quantum dot / polyvinylidene fluoride ink according to any one of claims 1 to 8 in the fields of wide color gamut LED backlight display, flexible display, and Mini-LED / Micro-LED full-color display.

11. A method for applying the color conversion all-inorganic perovskite quantum dot / polyvinylidene fluoride ink according to any one of claims 1 to 8 in a liquid crystal display, comprising: All-inorganic perovskite quantum dot / polyvinylidene fluoride ink is uniformly coated onto a substrate using a coating method. Then, the dispersant is evaporated at a certain temperature to obtain an all-inorganic perovskite quantum dot / polyvinylidene fluoride color conversion layer, which can be coated onto a blue LED light guide plate for use as backlight in liquid crystal displays.

12. The method for applying the all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion in a liquid crystal display according to claim 11, at a temperature of 10-90°C o The dispersant is evaporated within the range of C; the substrate is selected from glass and polyethylene terephthalate film.

13. The method of applying the all-inorganic perovskite quantum dot / polyvinylidene fluoride ink for color conversion as described in any one of claims 1 to 8 in a full-color display of Mini-LED / Micro-LED, comprising: All-inorganic perovskite quantum dot / polyvinylidene fluoride ink is printed onto the pixels of Mini-LED / Micro-LED chips using inkjet printing technology. After the dispersant evaporates, an all-inorganic perovskite quantum dot / polyvinylidene fluoride color conversion layer is obtained for full-color display of Mini-LED / Micro-LED.

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