Perovskite quantum dot film, perovskite quantum dot film color conversion Micro-LED display and preparation method of perovskite quantum dot film color conversion Micro-LED display

Abstract

The invention discloses a perovskite quantum dot film, a perovskite quantum dot film color conversion Micro-LED display and a preparation method of the perovskite quantum dot film color conversion Micro-LED display. According to the perovskite quantum dot film color conversion method, luminescence conversion of the perovskite quantum dot / polymer film is realized by adopting a femtosecond laser direct writing technology. According to the perovskite quantum dot film color conversion method, multicolor conversion of a single perovskite quantum dot film is realized by adopting a femtosecond laser direct writing technology, the positions and light emitting characteristics of pixels in different colors are accurately controlled, and the problem of light crosstalk is avoided. Not only is efficient color conversion realized, but also the problems of complexity and alignment precision of a traditional multi-step preparation process are avoided.

Description

Technical Field

[0001] The present invention belongs to the field of display technology, and specifically relates to a perovskite quantum dot film, a perovskite quantum dot film color conversion Micro-LED display and a preparation method thereof. Background Art

[0002] Micro-LED displays have gradually become an important development direction for the next generation of display technology due to their advantages such as high brightness, low power consumption, long life and fast response time. However, achieving RGB full-color display is one of the main challenges facing Micro-LED. Traditional methods usually require integrating LED chips of different colors or introducing complex color conversion materials, which not only increases the difficulty and cost of manufacturing, but may also cause color unevenness and light crosstalk problems.

[0003] Therefore, it is necessary to provide a new method for realizing RGB full-color display. Summary of the invention

[0004] To solve the above problems, the present invention provides a method for perovskite quantum dot film color conversion, which utilizes the unique photoelectric properties of perovskite quantum dots and adopts femtosecond laser direct writing technology to develop an innovative method for perovskite quantum dot film color conversion, further realizing RGB full-color display.

[0005] The present invention also provides a method for preparing a Micro-LED display based on the above-mentioned perovskite quantum dot film color conversion, which realizes RGB full-color display through a simple and efficient process. This method not only simplifies the preparation process and improves the display quality, but also reduces the production cost, and has important commercial value and application prospects.

[0006] Correspondingly, the present invention also provides a perovskite quantum dot film prepared by the above method and a perovskite quantum dot film color conversion Micro-LED display.

[0007] The present invention adopts the following technical solutions:

[0008] A method for color conversion of a perovskite quantum dot film, the method using femtosecond laser direct writing technology to achieve luminescence conversion of the perovskite quantum dot film, such as conversion of red light into green light. The femtosecond laser direct writing technology can selectively change the composition of quantum dots in a specific area, achieve the graphicization of red and green light on a single film, and simplify the preparation process of multi-color display.

[0009] Wherein, the method is implemented by femtosecond laser direct writing technology.

[0010] Wherein, the wavelength of the femtosecond laser is 355 to 405 nm, preferably 365 nm;

[0011] and / or, a power density of 100 to 1,000 mW / cm², preferably 500 mW / cm²;

[0012] And / or, the scanning speed is 10 to 100 μm / s, preferably 50 μm / s.

[0013] A method for preparing a perovskite quantum dot film color conversion Micro-LED display, characterized in that it comprises the following steps:

[0014] S1. Lamination of the luminescent film and the blue light Micro-LED chip: Lamination of the perovskite quantum dot / polymer film on the blue light Micro-LED chip; the prepared perovskite quantum dot / polymer film needs to be laminated on the blue light Micro-LED chip. In order to ensure the tightness and uniformity of the lamination, hot pressing, vacuum lamination or gluing can be selected for lamination. During the lamination process, parameters such as temperature, pressure and time need to be strictly controlled to avoid damage to the quantum dot film.

[0015] S2, converting pixels: using femtosecond laser direct writing technology to convert the predetermined pixel position of the perovskite quantum dot / polymer film into a predetermined luminescent color to achieve pixel conversion;

[0016] S3, blue light pixel emission: femtosecond laser is used to penetrate the perovskite quantum dots / polymer film at the position where the blue light chip emits light, thereby realizing the emission of blue light pixels;

[0017] S4. Covering with a black barrier layer: Covering the perovskite quantum dot / polymer film with a black barrier layer corresponding to the blue light Micro-LED to prevent light crosstalk, and finally realize RGB full-color display.

[0018] The preparation method of the perovskite quantum dot / polymer film in step S1 is: the precursor solution and the polymer solution are fully mixed in a certain proportion and then coated on the substrate, so that the precursor grows in situ into perovskite quantum dots on the polymer substrate.

[0019] Specifically, the method for preparing the perovskite quantum dot / polymer film comprises the following steps:

[0020] S1a: Preparation of precursor solution: Select halide as the precursor material of perovskite quantum dots and dissolve it in an appropriate solvent (such as DMF, DMSO, etc.) to form a uniform precursor solution. In order to improve the dispersibility and stability of quantum dots, an appropriate amount of surfactant or ligand (such as oleic acid, oleylamine, etc.) can be added to the precursor solution to modify the surface of quantum dots and prevent agglomeration.

[0021] S1b: Preparation of polymer solution (substrate): Selecting a polymer with good flexibility and optical transparency as the substrate material can ensure good adhesion between the film and the blue light Micro-LED chip.

[0022] S1c: Blending of precursor solution and polymer solution: The precursor solution and the polymer solution are mixed in a certain proportion to form a uniform composite solution. Stirring, ultrasonic treatment and other means are used to ensure that the precursor and the polymer are fully mixed to form a stable composite system. The mixed solution is further treated, such as filtration or centrifugation, to remove possible impurities and ensure the purity of the solution.

[0023] S1d: In-situ growth of perovskite quantum dots: The blended composite solution is coated on a substrate, and then the precursor is grown in-situ on the polymer substrate as perovskite quantum dots by heating, annealing or chemical reaction. By regulating parameters such as temperature, time, and atmosphere, the growth process of perovskite quantum dots can be precisely controlled to ensure uniform distribution and ideal optical properties. The resulting perovskite quantum dot / polymer film has excellent light emission characteristics and can achieve efficient color conversion under blue light excitation.

[0024] Wherein, the molar concentration of the precursor solution is 0.01 mM-1 M; the mass percentage of the polymer solution is 10-70%;

[0025] And / or, the volume ratio of the precursor solution to the polymer solution is 1:1 to 3:1.

[0026] Preferably, the precursor solution is obtained by dissolving AX and DMABX3 or BX2 in a solvent, that is, the precursor solution contains AX and DMABX3 or BX2, wherein A is Cs + 、MA + or FA + , X is Cl, Br or I; B is a divalent cation such as Pb, Sn, Mn or Zn, that is, AX is MAX, CsX or FAX, DMABX3 or BX2 is DMAPbX3 or PbX2, further, the molar ratio of AX to DMABX3 or BX2 is 3:1 to 1:3, preferably 1:1; AX can be one or a mixture of MAX, CsX or FAX (X = Cl, Br, I), DMABX3 or BX2 can also be one or a mixture of DMAPbX3, PbX2, SnX2, ZnX2.

[0027] Preferably, the solvent is a mixture of one or both of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), and the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 1:0 to 5:1, preferably 3:1.

[0028] Further, the molecular weight Mw of the polymer in the polymer solution is 70,000 to 1,000,000. The polymer can be selected from polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA), polyvinyl pyrrolidone (PVP), polystyrene (PS), polyimide (PI), polydimethylsiloxane (PDMS), polyacrylonitrile (PAN) and polycarbonate (PC), and its molecular weight Mw is 70,000 to 1,000,000, such as Mw = 70,000, 400,000 or 1,000,000; the solvent can be selected from DMSO and DMF, and the volume ratio thereof is 1:0 to 5:1, preferably 3:1.

[0029] In step S1c, the mixing ratio of the precursor solution to the polymer solution is 1:1 to 3:1, preferably 2:1; the stirring time is 1 to 6 hours, preferably 3 hours; the ultrasonic treatment time is 10 to 60 minutes, preferably 30 minutes; the filtration or centrifugation speed is 3,000 to 10,000 rpm, preferably 5,000 rpm.

[0030] Furthermore, in step S1d, the heating temperature is 60 to 150°C, preferably 100°C; the annealing time is 5 to 60 minutes, preferably 30 minutes; the atmosphere can be selected from air, nitrogen or argon, preferably nitrogen; and the film thickness is 1 to 100 μm, preferably 10 μm.

[0031] Wherein, in step S1, the lamination method is hot pressing, vacuum lamination or gluing; the lamination temperature is 80 to 150°C, preferably 120°C; the pressure is 0.1 to 1 MPa, preferably 0.5 MPa; the time is 1 to 10 minutes, preferably 5 minutes. The thickness of the adhesive layer or buffer layer is 0.1 to 1 μm, preferably 0.5 μm.

[0032] Preferably, in step S1, a transparent adhesive layer or buffer layer is added between the perovskite quantum dot / polymer film and the blue light Micro-LED chip. A transparent adhesive layer or buffer layer is added between the perovskite quantum dot / polymer film and the blue light chip to enhance the interface bonding force and optical transmission efficiency and ensure the bonding effect.

[0033] The anti-reflection film or anti-reflection coating material can be selected from silicon dioxide (SiO2), silicon nitride (Si3N4), etc.; the thickness is 50 to 200 nm, preferably 100 nm; the light emitting angle of the blue light chip is ±30° to ±60°, preferably ±45°.

[0034] Step S2 implements the pixel conversion.

[0035] In order to achieve color conversion, the present invention uses femtosecond laser direct writing technology to convert the pixels of perovskite quantum dots in a specific area (for example, from red light emission to green light emission). The specific steps are as follows:

[0036] S2a: Femtosecond laser direct writing: Use a femtosecond laser to selectively illuminate a predetermined pixel location (e.g., green light). Femtosecond lasers have extremely short pulse widths (typically 10 -15 The laser can be precisely processed at the micron or even submicron scale with almost no thermal effects, thus avoiding damage to surrounding materials. By adjusting the laser wavelength, power density, scanning speed and other parameters, the laser energy input can be precisely controlled to ensure that the perovskite quantum dots at the predetermined pixel position undergo a phase change.

[0037] S2b: Change in emission wavelength: After femtosecond laser irradiation, the composition of perovskite quantum dots in a local area changes, thereby changing the emission wavelength. For example, by adjusting the ratio of halogen ions, the perovskite quantum dots in that area can be changed from red light emission to green light emission, while other areas remain unchanged. This process not only achieves efficient color conversion, but also avoids the complexity and alignment accuracy problems of traditional multi-step preparation processes.

[0038] S3, blue light pixel emission: the position where the blue light chip emits light on the perovskite quantum dot / polymer film is knocked out by a femtosecond laser to achieve blue light pixel emission;

[0039] Step S3 realizes the light emission of the blue light pixel.

[0040] In order to realize the light emission of blue light pixels, the present invention uses a femtosecond laser to remove the perovskite quantum dot film at the light emission position of the blue light chip, exposing the light emitting area of ​​the blue light chip. The specific steps are as follows:

[0041] S3a: Femtosecond laser removal: Use a femtosecond laser to precisely illuminate the light-emitting position of the blue light chip, and instantly vaporize or ablate the perovskite quantum dot film at that position through high-energy-density laser pulses, exposing the light-emitting area of ​​the blue light chip. Since the action time of the femtosecond laser is extremely short, the entire process will not cause damage to the blue light chip, ensuring clear light emission of the blue light pixel.

[0042] S3b: Optimization of blue light pixels: In order to further improve the light output effect of blue light pixels, a transparent anti-reflection film or anti-reflection coating can be covered on the surface of the blue light chip to reduce light loss and improve light output efficiency. In addition, the design of the blue light chip can be optimized to adjust its light emission angle and light intensity distribution to ensure the light balance between blue light pixels and other color pixels. The thickness of the anti-reflection film or anti-reflection coating is 50 to 200 nm.

[0043] Wherein, in step S3, the wavelength of the femtosecond laser is 355 to 405 nm, preferably 365 nm;

[0044] Wherein, in step S3, the power density of the femtosecond laser is 1,000 to 10,000 mW / cm², preferably 5,000 mW / cm²;

[0045] Wherein, in step S3, the scanning speed of the femtosecond laser is 10 to 100 μm / s, preferably 50 μm / s.

[0046] Step S4 is to cover the black retaining wall layer.

[0047] Specifically, finally, a black barrier layer corresponding to the blue light Micro-LED is covered on the surface of the display to prevent light crosstalk between pixels of different colors and ensure the effect of RGB full-color display. The black barrier layer can be made of black resin, black polymer or other materials with high absorption rate, and covered on the surface of the display by spin coating, spraying or printing. The black barrier layer not only effectively prevents light crosstalk, but also improves the display contrast and color purity, further improving the display quality.

[0048] Furthermore, the black barrier layer material can be selected from black resin, black polymer, black pigment, etc.; the thickness is 1 to 10 μm, preferably 5 μm; the covering method can be selected from spin coating, spraying or printing; the light absorption rate of the black barrier layer is 90% to 99%, preferably 95%.

[0049] Wherein, the thickness of the perovskite quantum dot / polymer film ranges from 1 to 100 μm.

[0050] Wherein, the thickness of the black barrier layer is 1 to 10 μm.

[0051] A perovskite quantum dot film is prepared by using the above-mentioned perovskite quantum dot film color conversion method.

[0052] A perovskite quantum dot film color conversion Micro-LED display is prepared by the above-mentioned preparation method; the Micro-LED display comprises a blue light Micro-LED chip, a perovskite quantum dot / polymer film and a black barrier layer.

[0053] Beneficial effects of the present invention:

[0054] (1) The method of color conversion of perovskite quantum dot film of the present invention realizes multi-color conversion of a single perovskite quantum dot film by using femtosecond laser direct writing technology, accurately controls the position and luminescence characteristics of pixels of different colors, and avoids the problem of optical crosstalk. It not only realizes efficient color conversion, but also avoids the complexity and alignment accuracy problems of the traditional multi-step preparation process.

[0055] (2) The preparation method of the perovskite quantum dot film color conversion Micro-LED display of the present invention realizes RGB full-color display through a simple and efficient process.

[0056] (3) The perovskite quantum dot film of the present invention is prepared by blending the precursor with the polymer and then growing it in situ, thereby ensuring the uniformity and optical properties of the film and avoiding the complexity of the traditional multi-step preparation process.

[0057] (4) The effective design of the black barrier layer further improves the display quality, ensuring high contrast and color purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 Schematic diagram of the structure of the perovskite quantum dot film color conversion Micro-LED display according to an embodiment of the present invention.

[0059] Figure numerals: 001-perovskite quantum dot / PVDF film, 002-blue light Micro-LED chip, 003-predetermined green light pixel position; 004-light emitting area of ​​the blue light chip, 005-black resin barrier layer. DETAILED DESCRIPTION

[0060] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0061] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0062] Example 1

[0063] This embodiment adopts the method of perovskite quantum dot film color conversion to prepare the perovskite quantum dot film.

[0064] The perovskite quantum dot / polymer film was irradiated with a femtosecond laser having a wavelength of 355 nm, a power density of 1000 mW / cm², and a scanning speed of 10 µm / s. The raw material perovskite quantum dot / polymer film of this embodiment emits red light under blue light excitation, and after being processed by the film color conversion method of the present invention, the perovskite quantum dot / polymer film emits green light under blue light excitation.

[0065] Example 2

[0066] This embodiment adopts the method of perovskite quantum dot film color conversion to prepare the perovskite quantum dot film.

[0067] A femtosecond laser with a wavelength of 365 nm, a power density of 500 mW / cm², and a scanning speed of 50 µm / s was used to selectively irradiate the predetermined green light pixel position on the perovskite quantum dot / polymer film. The red light at the specific position of the perovskite quantum dot film of this embodiment was converted into green light.

[0068] Example 3

[0069] This embodiment adopts the method of perovskite quantum dot film color conversion to prepare the perovskite quantum dot film.

[0070] A femtosecond laser with a wavelength of 405 nm, a power density of 100 mW / cm², and a scanning speed of 100 µm / s was used to selectively irradiate the predetermined green light pixel position on the perovskite quantum dot / polymer film. The red light at the specific position of the perovskite quantum dot film of this embodiment was converted into green light.

[0071] Example 4

[0072] This embodiment adopts the preparation method of the perovskite quantum dot film color conversion Micro-LED display to prepare the perovskite quantum dot film color conversion Micro-LED display.

[0073] 0.9 mmol CsI, 0.36 mmol DMAPbI3, 0.54 mmol DMAPbBr3 and 0.6 g PVDF powder with a molecular weight of 1000000 were added to a mixed solvent of 5 mL DMF and 2.5 mL DMSO. The above ingredients were stirred for 3 hours and ultrasonically treated for 60 minutes to ensure sufficient and uniform mixing. Subsequently, impurities were removed by centrifugation at 5000 r / min to ensure the purity of the solution. Next, the obtained composite solution was coated on a glass substrate and annealed in a nitrogen environment at 100 °C for 30 minutes to promote the in-situ growth of perovskite quantum dots. This process ultimately formed a 10 µm thick perovskite quantum dot / PVDF film 001, which can efficiently convert into red light under blue light excitation.

[0074] See also Figure 1 The prepared perovskite quantum dot / PVDF film 001 was then attached to the blue light Micro-LED chip 002 by hot pressing technology. The operating conditions were 120°C, 0.5 MPa pressure, and duration of 5 min.

[0075] In order to achieve the transition from red light to green light, a femtosecond laser with a wavelength of 365 nm, a power density of 500 mW / cm², and a scanning speed of 50 µm / s is used to selectively irradiate the predetermined green light pixel position 003. Femtosecond lasers can process at micron-level precision with almost no thermal effect, thus avoiding damage to surrounding materials. After laser irradiation, the emission wavelength of the perovskite quantum dots changes from red light to green light, achieving efficient blue-to-green light conversion.

[0076] For blue light pixels, a femtosecond laser with a wavelength of 365 nm, a power density of 5000 mW / cm² and the same scanning speed is used to precisely illuminate the light-emitting area 004 of the blue light chip, instantly vaporizing or ablating the perovskite quantum dot layer there, exposing the light-emitting surface of the blue light chip. The entire process is performed quickly to prevent damage to the blue light chip.

[0077] Finally, in order to prevent light crosstalk between pixels of different colors and improve display contrast and color purity, the display surface is covered with a 5 µm thick black resin barrier layer 005, which is applied by spin coating. This black barrier has an absorbance of up to 95%, ensuring the high quality of RGB full-color display.

[0078] Figure 1 This is a schematic diagram of the structure of the perovskite quantum dot film color conversion Micro-LED display according to an embodiment of the present invention, see Figure 1 The perovskite quantum dot film color conversion Micro-LED display of the present invention comprises a perovskite quantum dot / PVDF film 001, a blue light Micro-LED chip 002 and a black resin barrier layer 005. The whole device preparation process is simple, the cost is low, and it has potential application prospects.

[0079] Example 5

[0080] This embodiment adopts the preparation method of the perovskite quantum dot film color conversion Micro-LED display to prepare the perovskite quantum dot film color conversion Micro-LED display.

[0081] In a mixed solvent of 12L DMF, 0.09 mol CsI, 0.016 mol DMAPbI3, and 0.014 mol DMAPbBr3 were added to obtain a precursor solution, and 1.2 kg of PVDF powder with a molecular weight of 1000000 was added to the mixed solvent of 12L DMF to obtain a polymer solution. The precursor solution and the polymer solution were mixed and stirred for 3 h in a volume ratio of 2:1, and ultrasonic treatment was performed for 60 min to ensure sufficient and uniform mixing. Subsequently, impurities were removed by centrifugation at 5000 r / min to ensure the purity of the solution. Next, the obtained composite solution was coated on a glass substrate and annealed in a nitrogen environment at 100 °C for 30 min to promote the in-situ growth of perovskite quantum dots. This process ultimately formed a 10 µm thick red-light-emitting perovskite quantum dot / PVDF film that can be efficiently converted into red light under blue light excitation.

[0082] The prepared red light film is then attached to the blue light Micro-LED chip by hot pressing technology, with the operating conditions of 120 ℃, 0.5 MPa pressure, and duration of 5 minutes. During this process, a 10 µm thick layer of transparent adhesive is added between the two to enhance the bonding strength and optical transmission efficiency and ensure good bonding quality.

[0083] In order to achieve the transition from red light to green light, a femtosecond laser with a wavelength of 365 nm, a power density of 500 mW / cm², and a scanning speed of 50 µm / s is used to selectively irradiate the predetermined green light pixel position. Femtosecond lasers can process with micron-level precision and produce almost no thermal effects, thus avoiding damage to surrounding materials. After laser irradiation, the emission wavelength of the perovskite quantum dots changes from red light to green light, achieving efficient blue-to-green light conversion.

[0084] For blue light pixels, a femtosecond laser with a wavelength of 365 nm, a power density of 5000 mW / cm² and the same scanning speed is used to precisely illuminate the light-emitting area of ​​the blue light chip, instantly vaporizing or ablating the perovskite quantum dot layer there, exposing the light-emitting surface of the blue light chip. The entire process is performed quickly to prevent damage to the blue light chip.

[0085] Finally, in order to prevent light crosstalk between pixels of different colors and improve display contrast and color purity, the display surface is covered with a 5 µm thick black resin barrier layer, which is applied by spin coating. This black barrier has a light absorption rate of up to 95%, ensuring the high-quality effect of RGB full-color display.

[0086] Example 6

[0087] This embodiment adopts the preparation method of the perovskite quantum dot film color conversion Micro-LED display to prepare the perovskite quantum dot film color conversion Micro-LED display.

[0088] In a mixed solvent of 3 mL DMF and 0.6 mL DMSO, 0.9 mmol CsI and 2.7 mmol DMAPbBr3 were added to obtain a precursor solution, and 2.6 g PVDF powder with a molecular weight of 1000000 was added to a mixed solvent of 3 mL DMF and 0.6 mL DMSO to obtain a polymer solution. The precursor solution and the polymer solution were mixed and stirred for 3 h in a volume ratio of 3:1, and ultrasonic treatment was performed for 60 min to ensure sufficient and uniform mixing. Subsequently, impurities were removed by centrifugation at 5000 r / min to ensure the purity of the solution. Next, the obtained composite solution was coated on a glass substrate and annealed in a nitrogen environment at 100 °C for 30 min to promote the in-situ growth of perovskite quantum dots. This process ultimately formed a 10 µm thick red-light-emitting perovskite quantum dot / PVDF film that can be efficiently converted into red light under blue light excitation.

[0089] The prepared red light film is then attached to the blue light Micro-LED chip by hot pressing technology, with the operating conditions of 120 ℃, 0.5 MPa pressure, and duration of 5 minutes. During this process, a 10 µm thick layer of transparent adhesive is added between the two to enhance the bonding strength and optical transmission efficiency and ensure good bonding quality.

[0090] In order to achieve the transition from red light to green light, a femtosecond laser with a wavelength of 365 nm, a power density of 500 mW / cm², and a scanning speed of 50 µm / s is used to selectively irradiate the predetermined green light pixel position. Femtosecond lasers can process with micron-level precision and produce almost no thermal effects, thus avoiding damage to surrounding materials. After laser irradiation, the emission wavelength of the perovskite quantum dots changes from red light to green light, achieving efficient blue-to-green light conversion.

[0091] For blue light pixels, a femtosecond laser with a wavelength of 365 nm, a power density of 5000 mW / cm², and the same scanning speed is used to precisely irradiate the light-emitting area of ​​the blue light chip, instantly vaporizing or ablating the perovskite quantum dot layer there, exposing the light-emitting surface of the blue light chip. The entire process is performed quickly to prevent damage to the blue light chip. Afterwards, a 100nm thick silicon dioxide (SiO2) anti-reflection film is deposited on the surface of the blue light chip to reduce light loss and improve light output efficiency. The design is adjusted so that the blue light emission angle reaches ±45° to ensure the light balance between the blue light and other color pixels.

[0092] Finally, in order to prevent light crosstalk between pixels of different colors and improve display contrast and color purity, the display surface is covered with a 5 µm thick black resin barrier layer, which is applied by spin coating. This black barrier has a light absorption rate of up to 95%, ensuring the high-quality effect of RGB full-color display.

[0093] Example 7

[0094] This embodiment adopts the preparation method of the perovskite quantum dot film color conversion Micro-LED display to prepare the perovskite quantum dot film color conversion Micro-LED display.

[0095] 1.8 mmol MABr, 1.8 mmol PbI2, and 1.2 g PVP (polyvinyl pyrrolidone) powder with a molecular weight of 1,500,000 were added to a mixed solvent of 10 mL DMF and 5 mL DMSO. The ingredients were stirred for 4 h and ultrasonicated for 90 min to ensure uniform mixing of the solution. Subsequently, the solution was centrifuged at 8,000 r / min to remove impurities. The composite solution was coated on an ITO conductive glass substrate and annealed in a nitrogen environment at 120 °C for 45 min to form an 8 µm thick red-light-emitting perovskite quantum dot / PVP film. The film can be efficiently converted into red light under blue light excitation.

[0096] In order to achieve the transition from red light to green light, a femtosecond laser with a wavelength of 365 nm, a power density of 400 mW / cm², and a scanning speed of 70 µm / s was used to selectively irradiate the predetermined green light pixel positions.

[0097] For the blue light pixel area, a femtosecond laser with a wavelength of 365 nm and a power density of 6,000 mW / cm² is used to precisely irradiate and ablate the perovskite quantum dot layer. After that, a 120 nm thick silicon dioxide anti-reflection film is deposited on the surface of the blue light chip, and the design is adjusted to make the blue light emission angle reach ±30°.

[0098] Finally, the display surface is covered with a 7 µm thick black resin barrier layer to improve display contrast and color purity.

[0099] Example 8

[0100] This embodiment adopts the preparation method of the perovskite quantum dot film color conversion Micro-LED display to prepare the perovskite quantum dot film color conversion Micro-LED display.

[0101] In a mixed solvent of 8 mL DMF and 4 mL DMSO, 4 mmol FAI, 4 mmol PbBr2 and 0.8 g PMMA (polymethyl methacrylate) powder with a molecular weight of 1,200,000 were added. The mixture was stirred for 5 h and ultrasonicated for 120 min to ensure thorough mixing. Then, the solution was centrifuged at 6,000 r / min to remove impurities. The resulting composite solution was spin-coated on a flexible PI (polyimide) substrate and annealed in a nitrogen environment at 150 °C for 60 min to form a 12 µm thick red-light-emitting perovskite quantum dot / PMMA film. This film can be converted into red light under blue light excitation.

[0102] To achieve the transition from red to green light, a femtosecond laser with a wavelength of 365 nm, a power density of 300 mW / cm², and a scanning speed of 60 µm / s was used to selectively illuminate the predetermined green light pixel positions.

[0103] For the blue light pixel area, a femtosecond laser with a wavelength of 365 nm and a power density of 6,000 mW / cm² is used to precisely irradiate and ablate the perovskite quantum dot layer. Then, an 80 nm thick aluminum oxide (Al2O3) anti-reflection film is deposited on the surface of all pixels to reduce light loss and improve light output efficiency.

[0104] Finally, a 10 µm thick black resin barrier layer is added to the display surface to ensure high-quality RGB full-color display and optimize light isolation between pixels of different colors, thereby improving display contrast and color purity.

[0105] The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for converting the color of a perovskite quantum dot film, characterized in that: The method adopts femtosecond laser direct writing technology to realize the luminescence conversion of perovskite quantum dots / polymer films.

2. The method according to claim 1, characterized in that: The wavelength of the femtosecond laser is 355 to 405 nm; and / or, a power density of 100 to 1,000 mW / cm²; And / or, the scanning speed is 10 to 100 μm / s.

3. A method for preparing a perovskite quantum dot film color conversion Micro-LED display, characterized in that: The following steps are involved: S1. Lamination of the luminescent film and the blue light Micro-LED chip: Lamination of the whole piece of perovskite quantum dot / polymer film on the blue light Micro-LED chip; S2, converting pixels: using femtosecond laser direct writing technology to convert the predetermined green light pixel position of the perovskite quantum dot / polymer film into green light, thereby realizing pixel conversion; S3, blue light pixel emission: femtosecond laser is used to penetrate the perovskite quantum dots / polymer film at the position where the blue light chip emits light, thereby realizing the emission of blue light pixels; S4. Covering with a black barrier layer: Covering the perovskite quantum dot / polymer film with a black barrier layer corresponding to the blue light Micro-LED to prevent light crosstalk, and finally realize RGB full-color display.

4. The preparation method according to claim 3, characterized in that: In step S1, the preparation method of the perovskite quantum dot / polymer film is: a precursor solution and a polymer solution are fully mixed in a certain proportion and then coated on a substrate, so that the precursor grows in situ on the polymer substrate to form perovskite quantum dots.

5. The preparation method according to claim 4, characterized in that: The molar concentration of the precursor solution is 0.01mM-1 M; the mass percentage of the polymer solution is 10-70%; And / or, the volume ratio of the precursor solution to the polymer solution is 1:1 to 3:

1.

6. The preparation method according to claim 4, characterized in that: The precursor solution contains a mixture of AX and BX2; wherein A is Cs + 、MA + or FA + ; X is Cl, Br or I; B is Pb, Sn, Mn or Zn; And / or, the solvent is one or a mixture of two of N,N-dimethylformamide and dimethyl sulfoxide.

7. The preparation method according to claim 6, characterized in that: In the precursor solution, the molar ratio of AX to BX2 is 3:1 to 1:3; Alternatively, the solvent is a mixture of N,N-dimethylformamide and dimethyl sulfoxide, and the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 1:0 to 5:

1.

8. The preparation method according to claim 4, characterized in that: The molecular weight Mw of the polymer in the polymer solution is 70,000 to 1,000,000.

9. The preparation method according to claim 3, characterized in that: In step S1, the lamination method is hot pressing, vacuum lamination or gluing; the lamination temperature is 80 to 150°C; the pressure is 0.1 to 1 MPa; and the time is 1 to 10 minutes.

10. The preparation method according to claim 3, characterized in that: In step S1, a transparent adhesive layer or a buffer layer is added between the perovskite quantum dot / polymer film and the blue light Micro-LED chip.

11. The preparation method according to claim 10, characterized in that: The thickness of the adhesive layer or the buffer layer is 0.1 to 1 μm.

12. The preparation method according to claim 3, characterized in that: The thickness of the perovskite quantum dot / polymer film ranges from 1 to 100 μm; And / or, the black barrier layer has a thickness of 1 to 10 μm.

13. The preparation method according to claim 3, characterized in that: In step S3, the wavelength of the femtosecond laser is 355 to 405 nm; and / or, a power density of 1,000 to 10,000 mW / cm²; And / or, the scanning speed is 10 to 100 μm / s.

14. A perovskite quantum dot film, characterized in that: The film is prepared by the method for converting the perovskite quantum dot film color as described in claim 1 or 2.

15. A perovskite quantum dot film color conversion Micro-LED display, characterized in that: Prepared by the preparation method described in claims 3 to 13; The Micro-LED display includes a blue light Micro-LED chip, a perovskite quantum dot / polymer film and a black barrier layer.

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