Core-shell colloidal quantum dot diode with zinc-indium-sulfur gradient layer and manufacturing method of core-shell colloidal quantum dot diode

Abstract

The invention discloses a core-shell colloidal quantum dot diode of a zinc-indium-sulfur gradient layer and a manufacturing method, and belongs to the field of light-emitting device research. A copper-indium-gallium-sulfur core quantum dot is synthesized through a thermal injection method, a zinc-indium-sulfur gradient layer and a zinc sulfide shell layer are sequentially grown on the surface of the copper-indium-gallium-sulfur core quantum dot to form a core-shell structure, and the zinc-indium-sulfur gradient layer optimizes the surface energy state of the quantum dot, reduces non-radiation quenching, improves the photoluminescence quantum yield and maintains narrow-band emission. And the copper-indium-gallium-sulfur quantum dots without heavy metals are adopted, so that the method is environment-friendly. During preparation, the indium tin oxide substrate is cleaned and subjected to plasma treatment, the aluminum electrode is deposited after each functional layer is spin-coated, the external quantum efficiency of the prepared light-emitting diode reaches 2.4%, the size of the quantum dots is about 3 nanometers, and the light-emitting wavelength can be regulated and controlled through the size and composition. The light-emitting diode is suitable for the fields of display and illumination, and has the advantages of high efficiency and environmental protection.

Description

Technical Field

[0001] The present invention relates to the research field of light-emitting devices, and in particular to a zinc-indium-sulfur gradient layer core-shell colloidal quantum dot diode and a manufacturing method thereof. Background Art

[0002] Colloidal quantum dot (CQD) light-emitting diodes (LEDs) are a new type of optoelectronic device based on semiconductor nanocrystals, attracting significant attention for their unique optical and electrical properties. Quantum dots typically range in size from 1 to 10 nanometers. This nanoscale dimension allows them to exhibit quantum confinement, allowing their emission wavelength to be precisely tuned by varying their size and composition. For example, the emission color of cadmium selenide (CdSe) quantum dots can be continuously tuned from blue to red, opening the door to the realization of high-color gamut, high-resolution display technologies. The basic structure of a QD LED is similar to that of an organic light-emitting diode (OLED), typically consisting of a quantum dot light-emitting layer sandwiched between two layers of electrodes. The inorganic semiconductor properties of QDs give them greater stability and a longer lifespan, while avoiding the aging and efficiency degradation issues common in organic materials used in OLEDs. In recent years, QD LED technology has made significant progress in the display and lighting fields, particularly in blue light emission. Researchers have significantly improved the efficiency and stability of blue QD LEDs by optimizing the interface layer and mixing materials.

[0003] However, quantum dots containing heavy metal elements, such as cadmium and lead, although they have excellent optical properties, pose serious hazards to the environment and human health. Cadmium and lead are both toxic heavy metals, and long-term exposure may lead to serious health problems such as kidney damage, nervous system disorders and cancer. In addition, quantum dots containing heavy metals may be released into the environment during production and use, causing pollution to soil, water bodies and ecosystems. For example, cadmium-containing quantum dots may seep into soil and water bodies after being discarded, causing toxic effects on animals and plants. Lead-based quantum dots also have similar problems. They are difficult to degrade in the environment and may be enriched through the food chain, ultimately affecting human health. These environmental and health risks have seriously restricted the commercial application of quantum dot light-emitting diode devices containing heavy metal quantum dots. Summary of the Invention

[0004] The purpose of the present invention is to overcome one or more deficiencies of the prior art and provide.

[0005] The object of the present invention is achieved through the following technical solutions:

[0006] To overcome the environmental and health concerns associated with heavy-metal quantum dots (QDs), researchers are committed to developing heavy-metal-free QD materials. Group I-III-VI QDs (such as copper indium sulfide and copper indium selenide), a key class of heavy-metal-free QD materials, have attracted widespread attention due to their excellent optical properties and environmental friendliness. Group I-III-VI QDs are completely free of heavy metals, making them safer for the environment and human health. By varying the size and composition of the QDs, the emission wavelength of Group I-III-VI QDs can be tuned across the entire visible light region, covering the full spectrum from blue to red. Furthermore, Group I-III-VI QDs offer high fluorescence quantum yields, enabling efficient emission. They can also be fabricated into films using low-cost solution processing techniques such as spin coating and inkjet printing, facilitating the fabrication of large-area, flexible displays and lighting devices. However, the synthesis of Group I-III-VI QDs is relatively complex, requiring precise control of reaction conditions to obtain high-quality QDs. Furthermore, the stability of Group I-III-VI QDs in devices needs to be further improved to meet the demands of practical applications.

[0007] In summary, colloidal quantum dot light-emitting diodes (QD-LEDs), as an emerging optoelectronic device, hold enormous potential for application. However, the environmental and health risks posed by QDs containing heavy metals cannot be ignored. Group I-III-VI QDs, as a heavy metal-free alternative, offer excellent optical properties and environmental friendliness, making them key to the sustainable development of QD-LED technology. With continued research and technological advancements, Group I-III-VI QDs are expected to achieve even wider applications in display and lighting.

[0008] Provided is a core-shell colloidal quantum dot light-emitting diode constructed based on a zinc-indium-sulfur gradient layer, characterized in that it includes:

[0009] Copper indium gallium sulfide core quantum dots, synthesized by hot injection;

[0010] A zinc indium sulfur gradient layer covering the surface of the copper indium gallium sulfur core quantum dots;

[0011] A zinc sulfide shell layer covering the surface of the zinc-indium-sulfur gradient layer;

[0012] The core-shell structured quantum dots improve the photoluminescence quantum yield (photoluminescence quantum yield) by constructing a zinc-indium-sulfur gradient layer while maintaining the narrow-band emission of the quantum dots themselves.

[0013] Furthermore, the method for preparing the light emitting diode comprises the following steps:

[0014] Synthesis of copper indium gallium sulfide core quantum dots: Oleic acid, dodecanethiol, indium acetate, gallium acetylacetonate, and copper iodide were added to a three-necked flask, heated and evacuated, and then sulfur solution was injected to increase the temperature to grow copper indium gallium sulfide cores;

[0015] Growth of zinc-indium-sulfur gradient layer: After cooling, inject zinc-indium-sulfur solution, then increase the temperature and maintain it for a period of time to grow the interface layer;

[0016] Growth of zinc sulfide shell: directly increase the temperature and inject zinc acetate solution, further increase the temperature and inject zinc stearate solution to complete the growth of the core-shell structure;

[0017] Substrate treatment and film preparation: The patterned ITO substrate was ultrasonically cleaned and plasma treated, followed by spin coating of PEDOT:PSS, TFB, quantum dots, and ZnMgO nanoparticle layers.

[0018] Electrode deposition: Aluminum electrodes are deposited on the film using a thermal evaporation system to complete the device preparation.

[0019] Furthermore, the size of the quantum dots is 3 nanometers, and the luminescence wavelength can be controlled by changing the size and composition.

[0020] Furthermore, the substrate cleaning step includes ultrasonic cleaning using detergent, deionized water and ethanol, followed by drying with nitrogen flow.

[0021] Furthermore, in the spin coating step of the quantum dots, the rotation speed is 3000 rpm and the duration is 20 seconds.

[0022] Furthermore, in the spin coating step of the zinc magnesium oxide (ZnMgO) nanoparticle layer, the rotation speed is 3000 rpm and the duration is 30 seconds.

[0023] Furthermore, the aluminum electrode has a thickness of 100 nanometers and is deposited by a thermal evaporation system.

[0024] Furthermore, the active area of ​​the light emitting diode is 4 square millimeters, which is defined by the overlapping area of ​​the ITO electrode and the aluminum electrode.

[0025] A display or lighting device comprises a plurality of the core-shell colloidal quantum dot light-emitting diodes as light-emitting units.

[0026] The beneficial effects of the present invention are:

[0027] (1) Synthesize copper indium gallium sulfur-zinc indium sulfur-zinc sulfide core-shell structure by hot injection method, construct zinc indium sulfur gradient layer, optimize the surface energy state of quantum dots, reduce non-radiative quenching caused by surface defect states, and achieve the effect of improving photoluminescence quantum yield while maintaining narrowband emission;

[0028] (2) Through the standardized preparation process of substrate treatment, multilayer film spin coating and electrode deposition, the efficient conversion of material properties to devices is achieved, and the effect of preparing high-stability and high-luminescence-efficiency quantum dot light-emitting diodes is achieved;

[0029] (3) By precisely controlling the size and composition of quantum dots and utilizing the quantum confinement effect, the luminescence wavelength can be flexibly adjusted within the entire visible light spectrum. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A flowchart of the steps of a method for manufacturing a core-shell colloidal quantum dot diode with a zinc-indium-sulfur gradient layer is provided for an embodiment of the present invention;

[0031] Figure 2 Transmission electron microscope image of copper indium gallium sulfur-zinc indium sulfur-zinc sulfide core-shell quantum dots;

[0032] Figure 3 Steady-state photoluminescence image of copper indium gallium sulfide-zinc indium sulfide-zinc sulfide core-shell quantum dots;

[0033] Figure 4 This is the time-resolved fluorescence spectrum image of copper indium gallium sulfide-zinc indium sulfide-zinc sulfide core-shell quantum dots;

[0034] Figure 5 Device efficiency image of copper indium gallium sulfide-zinc indium sulfide-zinc sulfide core-shell quantum dot light-emitting diodes. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the scope of protection of the present invention.

[0036] Example 1

[0037] See Figure 1 , provides a zinc-indium-sulfur gradient layer core-shell colloidal quantum dot diode and its manufacturing method

[0038] The preparation method comprises the following steps:

[0039] Synthesis of copper indium gallium sulfide core quantum dots: Oleic acid, dodecanethiol, indium acetate, gallium acetylacetonate, and copper iodide were added to a three-necked flask, heated and evacuated, and then sulfur solution was injected to increase the temperature to grow copper indium gallium sulfide cores;

[0040] Growth of zinc-indium-sulfur gradient layer: After cooling, inject zinc-indium-sulfur solution, then increase the temperature and maintain it for a period of time to grow the interface layer;

[0041] Growth of zinc sulfide shell: directly increase the temperature and inject zinc acetate solution, further increase the temperature and inject zinc stearate solution to complete the growth of the core-shell structure;

[0042] Substrate treatment and film preparation: The patterned ITO substrate was ultrasonically cleaned and plasma treated, followed by spin coating of PEDOT:PSS, TFB, quantum dots, and ZnMgO nanoparticle layers.

[0043] Electrode deposition: Aluminum electrodes are deposited on the film using a thermal evaporation system to complete the device preparation.

[0044] The specific steps include: the size of quantum dots is between 1-10 nanometers, and the luminescence wavelength is controlled by changing the size and composition.

[0045] The cleaning steps of the substrates included ultrasonic cleaning using detergent, deionized water, and ethanol, followed by drying with a nitrogen flow.

[0046] In the spin coating step of quantum dots, the rotation speed was 3000 rpm and the duration was 20 seconds.

[0047] The spin coating step of the zinc magnesium oxide (ZnMgO) nanoparticle layer was performed at a rotation speed of 3000 rpm for 30 seconds.

[0048] The aluminum electrodes had a thickness of 100 nm and were deposited by a thermal evaporation system.

[0049] The active area of ​​the LED is 4 square millimeters, defined by the overlapping area of ​​the ITO electrode and the aluminum electrode.

[0050] Example 2

[0051] Core-shell colloidal quantum dot light-emitting diodes based on zinc-indium-sulfur graded layers are as follows:

[0052] (1) First, copper indium gallium sulfur-zinc indium sulfur-zinc sulfide core / shell quantum dots were synthesized by hot injection. 2.5 mL of oleic acid (OLA), 0.25 mL of dodecanethiol (DDT), 0.0722 g of indium acetate, 0.0516 g of gallium acetylacetonate, and 0.0268 g of copper iodide were added to a 50 mL three-necked flask, heated to 125 °C, and evacuated for 30 minutes. Subsequently, 2 mL of sulfur solution was quickly injected, and the temperature was raised to 180 °C and maintained for 5 minutes to grow copper indium gallium sulfur cores. Then, the temperature was lowered to 150 °C, 4 mL of zinc indium sulfur solution was injected, and the temperature was raised to 190 °C and maintained for 10 minutes to grow the interface layer. Then, the temperature was directly raised to 210 °C, 6 mL of zinc acetate solution was injected and maintained for 30 minutes to grow the zinc sulfide shell layer. The temperature was then raised to 250 °C, and 4 mL of zinc stearate solution was slowly injected and maintained for 1 hour to complete the growth of the core / shell structure. Finally, the synthesized quantum dots were cooled to room temperature, purified, and stored in n-hexane at −5 °C.

[0053] (2) The patterned ITO substrate was ultrasonically cleaned using detergent, deionized water, and ethanol, followed by drying with a nitrogen stream and plasma treatment for 5 minutes. PEDOT:PSS was then spin-coated onto the cleaned ITO substrate at 3000 rpm for 30 seconds, annealed at 160°C for 30 minutes, and cooled for 10 minutes. Subsequently, a TFB solution (8 mg / ml) in chlorobenzene was spin-coated onto the ITO / PEDOT:PSS film at 3000 rpm for 30 seconds, annealed at 160°C for 30 minutes, and cooled for 10 minutes. Take a certain amount of 1 ml of the synthesized aluminum-doped copper indium sulfur quantum dot stock solution, add 6 ml of toluene solution, shake well and centrifuge roughly at a speed of 3000 rpm for 3 minutes. Take the upper clear liquid and divide it into two tubes evenly and add ethanol solution to 12 ml respectively, then centrifuge twice at a speed of 12000 rpm for 3 minutes. Then, the quantum dots are redispersed in 8 ml of toluene solution.

[0054] (3) Next, the quantum dots were spin-coated onto the ITO / PEDOT:PSS / TFB film at 3000 rpm for 20 seconds and allowed to cool for 5 minutes. Then, zinc magnesium oxide nanoparticles were spin-coated onto the ITO / PEDOT:PSS / TFB / QDs film at 3000 rpm for 30 seconds. Finally, aluminum was deposited on the film to a thickness of 100 nm using a thermal evaporation system to complete the device fabrication. The active area of ​​the device was 4 mm², defined by the overlap area of ​​the ITO and aluminum electrodes.

[0055] Example 3

[0056] Core-shell colloidal quantum dot light-emitting diodes based on zinc-indium-sulfur graded layers are as follows:

[0057] (1) First, copper indium gallium sulfur-zinc indium sulfur-zinc sulfide core / shell quantum dots were synthesized by hot injection. 2.5 mL of oleic acid (OLA), 0.25 mL of dodecanethiol (DDT), 0.0722 g of indium acetate, 0.0516 g of gallium acetylacetonate, and 0.0268 g of copper iodide were added to a 50 mL three-necked flask, heated to 125 °C, and evacuated for 30 minutes. Subsequently, 2 mL of sulfur solution was quickly injected, and the temperature was raised to 180 °C and maintained for 5 minutes to grow copper indium gallium sulfur cores. Then, the temperature was lowered to 150 °C, 2 mL of zinc indium sulfur solution was injected, and the temperature was raised to 190 °C and maintained for 10 minutes to grow the interface layer. Then, the temperature was directly raised to 210 °C, 6 mL of zinc acetate solution was injected and maintained for 30 minutes to grow the zinc sulfide shell layer, and then the temperature was raised to 250 °C, and 4 mL of zinc stearate solution was slowly injected and maintained for 1 hour to complete the growth of the core / shell structure. Finally, the synthesized quantum dots were cooled to room temperature, purified, and stored in n-hexane at −5 °C.

[0058] (2) The patterned ITO substrate was ultrasonically cleaned using detergent, deionized water, and ethanol, followed by drying with a nitrogen stream and plasma treatment for 5 minutes. PEDOT:PSS was then spin-coated onto the cleaned ITO substrate at 3000 rpm for 30 seconds, annealed at 160°C for 30 minutes, and cooled for 10 minutes. Subsequently, a TFB solution (8 mg / ml) in chlorobenzene was spin-coated onto the ITO / PEDOT:PSS film at 3000 rpm for 30 seconds, annealed at 160°C for 30 minutes, and cooled for 10 minutes. Take a certain amount of 1 ml of the synthesized aluminum-doped copper indium sulfur quantum dot stock solution, add 6 ml of toluene solution, shake well and centrifuge roughly at a speed of 3000 rpm for 3 minutes. Take the upper clear liquid and divide it into two tubes evenly and add ethanol solution to 12 ml respectively, then centrifuge twice at a speed of 12000 rpm for 3 minutes. Then, the quantum dots are redispersed in 8 ml of toluene solution.

[0059] (3) Next, the quantum dots were spin-coated onto the ITO / PEDOT:PSS / TFB film at 3000 rpm for 20 seconds and allowed to cool for 5 minutes. Then, zinc magnesium oxide nanoparticles were spin-coated onto the ITO / PEDOT:PSS / TFB / QDs film at 3000 rpm for 30 seconds. Finally, aluminum was deposited on the film to a thickness of 100 nm using a thermal evaporation system to complete the device fabrication. The active area of ​​the device was 4 mm², defined by the overlap area of ​​the ITO and aluminum electrodes.

[0060] Example 4

[0061] Core-shell colloidal quantum dot light-emitting diodes based on zinc-indium-sulfur graded layers are as follows:

[0062] (1) First, copper indium gallium sulfur-zinc indium sulfur-zinc sulfide core / shell quantum dots were synthesized by hot injection. 2.5 mL of oleic acid (OLA), 0.25 mL of dodecanethiol (DDT), 0.0722 g of indium acetate, 0.0516 g of gallium acetylacetonate, and 0.0268 g of copper iodide were added to a 50 mL three-necked flask, heated to 125 °C, and evacuated for 30 minutes. Subsequently, 2 mL of sulfur solution was quickly injected, and the temperature was raised to 180 °C and maintained for 5 minutes to grow copper indium gallium sulfur cores. Then, the temperature was lowered to 150 °C, 2 mL of zinc indium sulfur solution was injected, and the temperature was raised to 190 °C and maintained for 10 minutes to grow the interface layer. Then, the temperature was directly raised to 210 °C, 6 mL of zinc acetate solution was injected and maintained for 30 minutes to grow the zinc sulfide shell layer, and then the temperature was raised to 250 °C, and 1 mL of zinc stearate solution was slowly injected and maintained for 1 hour to complete the growth of the core / shell structure. Finally, the synthesized quantum dots were cooled to room temperature, purified, and stored in n-hexane at −5 °C.

[0063] (2) The patterned ITO substrate was ultrasonically cleaned using detergent, deionized water, and ethanol, followed by drying with a nitrogen stream and plasma treatment for 5 minutes. PEDOT:PSS was then spin-coated onto the cleaned ITO substrate at 3000 rpm for 30 seconds, annealed at 160°C for 30 minutes, and cooled for 10 minutes. Subsequently, a TFB solution (8 mg / ml) in chlorobenzene was spin-coated onto the ITO / PEDOT:PSS film at 3000 rpm for 30 seconds, annealed at 160°C for 30 minutes, and cooled for 10 minutes. Take a certain amount of 1 ml of the synthesized aluminum-doped copper indium sulfur quantum dot stock solution, add 6 ml of toluene solution, shake well and centrifuge roughly at a speed of 3000 rpm for 3 minutes. Take the upper clear liquid and divide it into two tubes evenly and add ethanol solution to 12 ml respectively, then centrifuge twice at a speed of 12000 rpm for 3 minutes. Then, the quantum dots are redispersed in 8 ml of toluene solution.

[0064] (3) Next, the quantum dots were spin-coated onto the ITO / PEDOT:PSS / TFB film at 3000 rpm for 20 seconds and allowed to cool for 5 minutes. Then, zinc magnesium oxide nanoparticles were spin-coated onto the ITO / PEDOT:PSS / TFB / QDs film at 3000 rpm for 30 seconds. Finally, aluminum was deposited on the film to a thickness of 100 nm using a thermal evaporation system to complete the device fabrication. The active area of ​​the device was 4 mm², defined by the overlap area of ​​the ITO and aluminum electrodes.

[0065] The morphology of the copper indium gallium sulfur-zinc indium sulfur-zinc sulfide quantum dots prepared in Example 1 was analyzed, and the transmission electron microscope analysis showed that Figure 2 The images show that the quantum dots are regular spherical with a particle size of approximately 20 nm and a clear core-shell boundary, indicating that the hot injection method has successfully synthesized multilayer core-shell quantum dots. The uniform coating of the zinc-indium-sulfur gradient layer and the zinc sulfide shell layer was verified, demonstrating the effectiveness of the synthesis process (such as temperature control and solution injection sequence).

[0066] The steady-state fluorescence photoluminescence spectrum of copper indium gallium sulfur-zinc indium sulfur-zinc sulfide quantum dots in toluene is visible Figure 3 The spectrum shows a single, intense luminescence peak with a narrow half-width (FWHM) (<80nm) and a significantly improved fluorescence quantum yield (PLQY). The narrow FWHM indicates a uniform size distribution of the quantum dots, consistent with the technical goal of "maintaining narrowband emission." The high PLQY demonstrates the effectiveness of the graded layer design, which reduces non-radiative quenching caused by surface defects.

[0067] Based on the quantum dot light-emitting diode prepared in Example 1, the specific parameters are: copper indium gallium sulfide-zinc indium sulfide-zinc sulfide quantum dots as the light-emitting layer, PEDOT:PSS as the hole transport layer, and ZnMgO as the electron transport layer. The device performance test is carried out. Figure 4-Figure 5 As shown, its external quantum efficiency reaches 2.4%. The decay curve shows a long fluorescence lifetime (estimated to be >10ns), indicating that the radiative recombination efficiency of excitons in the quantum dots is high and the non-radiative recombination process is effectively suppressed. The fluorescence lifetime further proves that the graded layer reduces surface defect states, which is consistent with the mechanism of "guiding carriers to the core region and promoting radiative recombination" in the invention content. Compared with the short-lived defects of traditional heavy metal-free quantum dots (such as copper indium sulfide), the method of the present invention improves the carrier utilization efficiency through structural design. EQE is the core indicator for measuring the luminous efficiency of a device. The value of 2.4% proves that the present invention has achieved an effective transformation from material performance to device application through the optimization of the core-shell structure.

[0068] By constructing a core-shell quantum dot structure with a zinc-indium-sulfur gradient layer, optimizing the surface energy state and reducing non-radiative recombination, the photoluminescence quantum yield is significantly improved while maintaining the narrow-band emission characteristics; by using heavy metal-free I-III-VI group copper indium gallium sulfur quantum dot materials, toxic elements such as cadmium and lead are completely eliminated, achieving an environmentally friendly and health-safe effect; through standardized preparation processes of substrate treatment, multilayer film spin coating and electrode deposition, the efficient conversion of material properties to devices is achieved, achieving the effect of preparing highly stable and high-luminescence-efficiency quantum dot light-emitting diodes; by precisely controlling the size and composition of quantum dots and utilizing the quantum confinement effect, the emission wavelength can be flexibly adjusted within the entire visible light spectrum.

[0069] The foregoing description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Rather, the present invention can be used in various other combinations, modifications, and environments and can be modified within the scope of the concept described herein through the above teachings or techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the appended claims.

Claims

1. A core-shell colloidal quantum dot light-emitting diode based on a zinc-indium-sulfur gradient layer, characterized in that: include: Copper indium gallium sulfide core quantum dots, synthesized by hot injection; A zinc indium sulfur gradient layer covering the surface of the copper indium gallium sulfur core quantum dots; A zinc sulfide shell layer covers the surface of the zinc-indium-sulfur gradient layer.

2. The core-shell colloidal quantum dot light-emitting diode according to claim 1, characterized in that: The method for preparing the light emitting diode comprises the following steps: Synthesis of copper indium gallium sulfide core quantum dots: Oleic acid, dodecanethiol, indium acetate, gallium acetylacetonate, and copper iodide were added to a three-necked flask, heated and evacuated, and then sulfur solution was injected to increase the temperature to grow copper indium gallium sulfide cores; Growth of zinc-indium-sulfur gradient layer: After cooling, inject zinc-indium-sulfur solution, then increase the temperature and maintain it for a period of time to grow the interface layer; Growth of zinc sulfide shell: directly increase the temperature and inject zinc acetate solution, further increase the temperature and inject zinc stearate solution to complete the growth of the core-shell structure; Substrate treatment and film preparation: The patterned ITO substrate was ultrasonically cleaned and plasma treated, followed by spin coating of PEDOT:PSS, TFB, quantum dots, and ZnMgO nanoparticle layers. Electrode deposition: Aluminum electrodes are deposited on the film using a thermal evaporation system to complete the device preparation.

3. The core-shell colloidal quantum dot light-emitting diode according to claim 1, characterized in that: The size of the quantum dots is 3 nanometers, and the luminescence wavelength can be controlled by changing the size and composition.

4. The method for preparing a core-shell colloidal quantum dot light-emitting diode according to claim 2, wherein: The substrate cleaning step includes ultrasonic cleaning using detergent, deionized water and ethanol, followed by drying with a nitrogen flow.

5. The method for preparing a core-shell colloidal quantum dot light-emitting diode according to claim 2, wherein: In the spin coating step of the quantum dots, the rotation speed is 3000 rpm and the duration is 20 seconds.

6. The method for preparing a core-shell colloidal quantum dot light-emitting diode according to claim 2, wherein: In the spin coating step of the zinc magnesium oxide nanoparticle layer, the rotation speed is 3000 rpm and the duration is 30 seconds.

7. The method for preparing a core-shell colloidal quantum dot light-emitting diode according to claim 2, characterized in that: The aluminum electrode has a thickness of 100 nanometers and is deposited by a thermal evaporation system.

8. The core-shell colloidal quantum dot light-emitting diode according to claim 1, characterized in that: The active area of ​​the light-emitting diode is 4 square millimeters, which is defined by the overlapping area of ​​the ITO electrode and the aluminum electrode.

9. A display or lighting device, characterized in that: It comprises a plurality of core-shell colloidal quantum dot light-emitting diodes as claimed in claim 1 as light-emitting units.

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