Quantum dot light-emitting diode device and method for preparing the same

Abstract

The present application discloses a quantum dot light-emitting diode device and a preparation method thereof. The quantum dot light-emitting diode device includes a cathode, an anode, and a stack disposed between the cathode and the anode. The stack includes a quantum dot light-emitting layer, an electron transport layer, and a film layer containing silver halide disposed between the quantum dot light-emitting layer and the electron transport layer. The quantum dot light-emitting layer is disposed close to the anode, and the electron transport layer is disposed close to the cathode. The present application can inhibit the formation of photo-generated holes in the electron transport layer, slow down the performance decay rate, and can also slow down the electron injection rate, and improve the imbalance state of electron and hole injection.

Description

Technical Field

[0001] This application relates to the technical field of quantum dot optoelectronic devices, and particularly to a quantum dot light emitting diode device and a preparation method thereof. Background Art

[0002] Due to its unique optoelectronic properties, quantum dot materials are considered to have wide applications in the fields of photovoltaic power generation and optoelectronic display, and have become a research hotspot. In the preparation of optoelectronic devices, the spin coating method has the characteristics of mild process conditions, simple operation, energy conservation and environmental protection. The optoelectronic devices prepared by it have advantages such as high carrier mobility and precise thickness. At present, the spin coating method is the most commonly used method for preparing quantum dot light emitting diodes (QLEDs).

[0003] In the field of optoelectronic display, as a light emitting unit, QLEDs are mainly divided into red, green, and blue primary color devices. After preliminary exploration, significant breakthroughs have been made in red and green devices, which basically meet the commercial requirements. At the same time, the development of blue QLEDs lags far behind that of red and green QLEDs, becoming a shortcoming of quantum dot optoelectronic display. Therefore, improving the performance of blue QLEDs is the key to realizing the commercialization of quantum dot optoelectronic display and is also a research hotspot in the field of quantum dots.

[0004] The QLED structure mainly includes a conductive glass substrate, a hole transport layer, a quantum dot composite light emitting layer, an electron transport layer, and a metal cathode. At present, the electron transport layer material is mainly selected from nano N-type semiconductor materials. At the nano scale, these materials have good photocatalytic properties (that is, photo-generated electrons and photo-generated holes are formed under light excitation), and their photocatalytic properties are better as the light energy increases. In blue devices, since the device emits high-energy blue light, it can effectively excite the electrons in the lowest unoccupied molecular orbital (LUMO) of the electron transport layer material to form photo-generated holes. Photo-generated holes have strong oxidizing properties and can quickly oxidize the ligands on the surface of the quantum dot material, and reduce the binding ability of the quantum dot shell to the excitons in the quantum dot core, thereby destroying the optoelectronic performance of the device. Therefore, how to inhibit the formation of photo-generated holes in the electron transport layer material to protect the quantum dot material is an urgent problem to be solved in improving the performance of quantum dot light emitting diode devices. Summary of the Invention

[0005] To solve the problem that the photo-generated holes formed by the excitation of the electron transport layer material damage the performance of the quantum dot device, the embodiments of this application provide a quantum dot light emitting diode device and a preparation method thereof, especially a blue quantum dot light emitting diode device and a preparation method thereof.

[0006] An embodiment of the present application provides a quantum dot light-emitting diode device, including a cathode, an anode, and a stack disposed between the cathode and the anode. The stack includes a quantum dot light-emitting layer, an electron transport layer, and a film layer containing silver halide disposed between the quantum dot light-emitting layer and the electron transport layer. The quantum dot light-emitting layer is disposed close to the anode, and the electron transport layer is disposed close to the cathode.

[0007] Optionally, in some embodiments of the present application, the film layer containing silver halide is a silver halide layer.

[0008] Optionally, in some embodiments of the present application, the film layer containing silver halide further includes a photocatalyst.

[0009] Optionally, in some embodiments of the present application, the silver halide is silver chloride, silver bromide, or silver iodide.

[0010] Optionally, in some embodiments of the present application, the quantum dot light-emitting layer includes blue quantum dots, green quantum dots, or red quantum dots. The blue quantum dots include at least one of CdZnS, CdZnSe, CdS / ZnS, CdZnS / ZnS, CdZnSe / ZnSe / ZnS, CdZnSe / ZnSe / CdZnS, ZnSeTe / ZnSe / ZnS, ZnSTe / ZnSe / ZnS, ZnSeTe / ZnS, CsPbCl3, and CsPbCl2Br. The green quantum dots include at least one of CdZnSeS, CdZnSeS / ZnSe / ZnS, CdZnSe / ZnS, CdZnSe / CdS, CdZnSe / ZnSe / ZnS, ZnSeTe / ZnSe / ZnS, ZnSeTe / ZnS InP / ZnS, InP / ZnSe / ZnS, and CsPbBr3. The red quantum dots include at least one of CdSeS, CdZnSeS, CdZnSeS / ZnSe, CdZnSeS / ZnS, CdSe / ZnS, CdZnSe / CdZnSe / ZnS, CdZnSe / CdZnSe / ZnSe / ZnS, InP / ZnS, InP / ZnSe / ZnS, CsPbI3, CuInS2 / ZnSe / ZnS, and CuInS2 / ZnS.

[0011] Correspondingly, an embodiment of the present application further provides a method for manufacturing a quantum dot light-emitting diode device, including the following steps:

[0012] Prepare a quantum dot light-emitting layer on an anode substrate;

[0013] Prepare a film layer containing silver halide on the quantum dot light-emitting layer;

[0014] An electron transport layer is prepared on the silver halide-containing film layer;

[0015] A cathode is prepared on the electron transport layer to obtain the quantum dot light-emitting diode device;

[0016] Alternatively, an electron transport layer is prepared on a cathode substrate;

[0017] A silver halide-containing film layer is prepared on the electron transport layer;

[0018] A quantum dot light-emitting layer is prepared on the silver halide-containing film layer;

[0019] An anode is prepared on the quantum dot light-emitting layer to obtain the quantum dot light-emitting diode device.

[0020] Optionally, in some embodiments of the present application, the step of preparing a silver halide-containing film layer on the quantum dot light-emitting layer includes:

[0021] First depositing a silver salt solution and then depositing a halogen salt solution, or first depositing a halogen salt solution and then depositing a silver salt solution;

[0022] Alternatively, the step of preparing a silver halide-containing film layer on the electron transport layer includes:

[0023] First depositing a silver salt solution and then depositing a halogen salt solution, or first depositing a halogen salt solution and then depositing a silver salt solution.

[0024] Optionally, in some embodiments of the present application, the silver salt is a soluble silver salt, and the halogen salt is a soluble chloride salt, a soluble bromide salt, or a soluble iodide salt.

[0025] Optionally, in some embodiments of the present application, the soluble silver salt is silver nitrate or silver fluoride; the soluble chloride salt is magnesium chloride, calcium chloride, ammonium chloride, sodium chloride, or zinc chloride; the soluble bromide salt is ammonium bromide, sodium bromide, or potassium bromide; the soluble iodide salt is ammonium iodide, sodium iodide, or potassium iodide.

[0026] Optionally, in some embodiments of the present application, the quantum dot light-emitting layer includes blue quantum dots, green quantum dots or red quantum dots. The blue quantum dots include at least one of CdZnS, CdZnSe, CdS / ZnS, CdZnS / ZnS, CdZnSe / ZnSe / ZnS, CdZnSe / ZnSe / CdZnS, ZnSeTe / ZnSe / ZnS, ZnSTe / ZnSe / ZnS, ZnSeTe / ZnS, CsPbCl3 and CsPbCl2Br. The green quantum dots include at least one of CdZnSeS, CdZnSeS / ZnSe / ZnS, CdZnSe / ZnS, CdZnSe / CdS, CdZnSe / ZnSe / ZnS, ZnSeTe / ZnSe / ZnS, ZnSeTe / ZnS, InP / ZnS, InP / ZnSe / ZnS and CsPbBr3. The red quantum dots include at least one of CdSeS, CdZnSeS, CdZnSeS / ZnSe, CdZnSeS / ZnS, CdSe / ZnS, CdZnSe / CdZnSe / ZnS, CdZnSe / CdZnSe / ZnSe / ZnS, InP / ZnS, InP / ZnSe / ZnS, CsPbI3, CuInS2 / ZnSe / ZnS and CuInS2 / ZnS.

[0027] Optionally, in some embodiments of the present application, the concentration of the silver salt in the silver salt solution is 10 to 100 mg / mL, and the concentration of the halide salt in the halide salt solution is 10 to 100 mg / mL.

[0028] Optionally, in some embodiments of the present application, the spin coating speeds of the silver salt solution and the halide salt solution are both 1000 to 5000 revolutions per minute, and the spin coating times are both 30 to 90 seconds.

[0029] In the present application, a film layer containing silver halide is added between the quantum dot light-emitting layer and the electron transport layer. The silver halide undergoes a decomposition reaction under short-wavelength light irradiation to form free silver atoms and halogen atoms. The silver atoms can effectively absorb visible light, greatly reducing the light irradiation intensity on the surface of the electron transport layer, inhibiting the generation of photo-generated holes in the electron transport layer, protecting the surface structure of the quantum dot material, slowing down the attenuation rate of the device performance, and by inhibiting the formation of photo-generated holes in the electron transport layer, the stability of the device can also be effectively improved, optimizing the lifetime performance of the device. At the same time, the newly added film layer containing silver halide can also slow down the electron injection rate inside the device to a certain extent, which is beneficial to improving the imbalance state of more electrons and fewer holes in the quantum dot light-emitting diode, reducing the internal charge accumulation in the device, and enhancing the quantum efficiency of the device. Description of the Drawings

[0030] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0031] Figure 1 It is a schematic structural diagram of a normal structure of a quantum dot light-emitting diode device provided by an embodiment of the present application;

[0032] Figure 2 It is a schematic structural diagram of an inverted structure of a quantum dot light-emitting diode device provided by an embodiment of the present application;

[0033] Figure 3 It is a schematic structural diagram of another normal structure of a quantum dot light-emitting diode device provided by an embodiment of the present application;

[0034] Figure 4 It is a schematic structural diagram of another inverted structure of a quantum dot light-emitting diode device provided by an embodiment of the present application;

[0035] Figure 5 It is a flowchart of a preparation method for a normal structure of a quantum dot light-emitting diode device provided by an embodiment of the present application;

[0036] Figure 6 It is a flowchart of a preparation method for an inverted structure of a quantum dot light-emitting diode device provided by an embodiment of the present application. Detailed implementation manners

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0038] Embodiments of the present application provide a quantum dot light-emitting diode device and a method for manufacturing the same. The following will be described in detail respectively. It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments. In addition, in the description of the present application, the term "comprising" means "including but not limited to". Various embodiments of the present invention may exist in a range format; it should be understood that the description in a range format is only for convenience and brevity and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0039] Please refer to Figure 1 and Figure 2 , embodiments of the present application provide a quantum dot light-emitting diode device, including an anode 110, a cathode 120, and a stack disposed between the anode 110 and the cathode 120. The stack includes a quantum dot light-emitting layer 130, an electron transport layer 140, and a silver halide-containing film layer 150 disposed between the quantum dot light-emitting layer 130 and the electron transport layer 140. The quantum dot light-emitting layer 130 is disposed close to the anode 110, and the electron transport layer 140 is disposed close to the cathode 120.

[0040] In addition to silver halide, the silver halide-containing film layer 150 may further include other components, such as a photocatalyst. The photocatalyst is, for example, a cuprous oxide photocatalyst. The photocatalyst is used to increase the sensitivity of silver halide to visible light.

[0041] In some embodiments of the present application, the silver halide-containing film layer 150 is a silver halide layer.

[0042] In some embodiments of the present application, the silver halide is silver chloride, silver bromide, or silver iodide.

[0043] In an embodiment of the present application, the quantum dot light-emitting layer 130 includes a quantum dot material. It can be understood that the material of the quantum dot light-emitting layer 130 may include other fluorescent, phosphorescent, organic and other light-emitting materials in addition to quantum dot nanoparticles. The quantum dot material may be, for example, at least one of group II-VI single-component quantum dots or core-shell structure quantum dots or alloy structure quantum dot materials, group III-V single-component quantum dots or core-shell structure quantum dots or alloy structure quantum dot materials, organic-inorganic hybrid perovskite quantum dot materials, and all-inorganic perovskite quantum dot materials. In some embodiments of the present application, the quantum dot light-emitting layer 130 includes blue light quantum dots, green light quantum dots or red light quantum dots. The blue light quantum dots include at least one of CdZnS, CdZnSe, CdS / ZnS, CdZnS / ZnS, CdZnSe / ZnSe / ZnS, CdZnSe / ZnSe / CdZnS, ZnSeTe / ZnSe / ZnS, ZnSTe / ZnSe / ZnS, ZnSeTe / ZnS, CsPbCl3, and CsPbCl2Br. The green light quantum dots include at least one of CdZnSeS, CdZnSeS / ZnSe / ZnS, CdZnSe / ZnS, CdZnSe / CdS, CdZnSe / ZnSe / ZnS, ZnSeTe / ZnSe / ZnS, ZnSeTe / ZnS InP / ZnS, InP / ZnSe / ZnS, and CsPbBr3. The red light quantum dots include at least one of CdSeS, CdZnSeS, CdZnSeS / ZnSe, CdZnSeS / ZnS, CdSe / ZnS, CdZnSe / CdZnSe / ZnS, CdZnSe / CdZnSe / ZnSe / ZnS, InP / ZnS, InP / ZnSe / ZnS, CsPbI3, CuInS2 / ZnSe / ZnS, and CuInS2 / ZnS. It can be understood that some of the specific components of the above blue light quantum dots, red light quantum dots and green light quantum dots are the same, because the emission wavelength of quantum dots is jointly determined by their particle size and composition. Under the same material structure, by changing the particle size of the quantum dots and / or the composition ratio of the quantum dots, the wavelength of the quantum dots can be adjusted, and then quantum dots with corresponding wavelengths can be obtained.

[0044] In the embodiment of the present application, a film layer 150 containing silver halide is added between the quantum dot light-emitting layer 130 and the electron transport layer 140. The silver halide microcrystals in the film layer 150 containing silver halide undergo a decomposition reaction under the irradiation of short-wavelength light (such as blue light, red light, and green light), forming free silver atoms and halogen atoms. The silver atoms can effectively absorb visible light, greatly reducing the light irradiation intensity on the surface of the electron transport layer 140. Furthermore, the generation of photo-generated holes in the electron transport layer 140 can be inhibited, protecting the surface structure of the quantum dot material, slowing down the attenuation rate of device performance. By inhibiting the generation of holes in the electron transport layer 140, the stability of the device can also be effectively improved, optimizing the lifetime performance of the device. At the same time, the newly added film layer 150 containing silver halide can also slow down the electron injection rate inside the device to a certain extent, which is beneficial to improving the unbalanced state of more electrons and fewer holes in the quantum dot light-emitting diode, reducing the charge accumulation inside the device, and enhancing the quantum efficiency of the device.

[0045] It can be understood that the quantum dot light-emitting diode device described in the embodiment of the present application can be a blue light quantum dot light-emitting diode device, a red light quantum dot light-emitting diode device, or a green light quantum dot light-emitting diode device. By adding a film layer 150 containing silver halide between the quantum dot light-emitting layer 130 and the electron transport layer 140, it can produce the effect of alleviating the photocatalysis phenomenon for red light quantum dot light-emitting diode devices, green light quantum dot light-emitting diode devices, and blue light quantum dot light-emitting diode devices. Since the blue light emitted by the blue light quantum dot light-emitting diode device has a higher energy, the blue light excites electrons in the material of the electron transport layer 140 to form photo-generated holes, thereby oxidizing the surface ligands of the quantum dot material and reducing the binding ability of the quantum dot shell to the excitons in the quantum dot core, damaging the optoelectronic performance of the device. Therefore, the photocatalysis phenomenon in blue light is stronger, while the excitation energy of red light and green light for the electron transport layer 140 is relatively weak, and the photocatalysis phenomenon in red light quantum dot light-emitting diode devices and green light quantum dot light-emitting diode devices is weaker. Therefore, compared with being used in red light quantum dot light-emitting diode devices and green light quantum dot light-emitting diode devices, the film layer 150 containing silver halide has a more significant effect of alleviating the photocatalysis phenomenon when used in blue light quantum dot light-emitting diode devices.

[0046] The quantum dot light-emitting diode device described in the embodiment of the present application can be a normal structure or an inverted structure. In the normal structure, the anode 110 is disposed on the substrate 100; in the inverted structure, the cathode 120 is disposed on the substrate 100. Whether it is a normal structure or an inverted structure, hole functional layers such as a hole transport layer, a hole injection layer, and / or an electron blocking layer can also be disposed between the anode 110 and the quantum dot light-emitting layer 130, and electron functional layers such as an electron injection layer and / or a hole blocking layer can also be disposed between the cathode 120 and the quantum dot light-emitting layer 130.

[0047] Such asFigure 3 and Figure 4 As shown in Figure 4 , in some embodiments of the present application, the quantum dot light-emitting diode device further includes a hole transport layer 160, and the hole transport layer 160 is disposed on a side of the quantum dot light-emitting layer 130 close to the anode 110. For example, the hole transport layer 160 is disposed between the anode 110 and the quantum dot light-emitting layer 130.

[0048] Exemplarily, Figure 3 FIG. Figure 3 shows another schematic diagram of the positive structure of the quantum dot light-emitting diode device according to an embodiment of the present application. As Figure 3 shown in Figure 3 , the positive structure quantum dot light-emitting diode device includes a substrate 100, an anode 110 disposed on the surface of the substrate 100, a hole transport layer 160 disposed on the surface of the anode 110, a quantum dot light-emitting layer 130 disposed on the surface of the hole transport layer 160, a silver halide-containing film layer 150 disposed on the surface of the quantum dot light-emitting layer 130, an electron transport layer 140 disposed on the surface of the silver halide-containing film layer 150, and a cathode 120 disposed on the surface of the electron transport layer 140.

[0049] Exemplarily, Figure 4 FIG. Figure 4 shows another schematic diagram of the inverted structure of the quantum dot light-emitting diode device according to an embodiment of the present application. As Figure 4 shown in Figure 4 , the inverted structure quantum dot light-emitting diode device includes a substrate 100, a cathode 120 disposed on the surface of the substrate 100, an electron transport layer 140 disposed on the surface of the cathode 120, a silver halide-containing film layer 150 disposed on the surface of the electron transport layer 140, a quantum dot light-emitting layer 130 disposed on the surface of the silver halide-containing film layer 150, a hole transport layer 160 disposed on the surface of the quantum dot light-emitting layer 130, and an anode 110 disposed on the surface of the hole transport layer 160.

[0050] In each embodiment of the present application, the materials of each functional layer are common materials in the art. For example:

[0051] The substrate 100 may be a rigid substrate or a flexible substrate. The substrate 100 is, for example, a glass substrate.

[0052] The anode 110 is, for example, ITO or FTO.

[0053] The cathode 120 may be, for example, a metal material such as aluminum, magnesium, calcium, silver, or an alloy material thereof.

[0054] The material of the electron transport layer 140 may be, for example, an N-type nano metal oxide. The N-type nano metal oxide may be, for example, at least one of zinc oxide, titanium dioxide, magnesium oxide, aluminum oxide, and oxides of the above metal alloys.

[0055] The material of the hole transport layer 160 can be, for example, TFB (poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine)), P3HT (3-hexyl-substituted polythiophene), PVK (poly(9-vinylcarbazole)), poly-TPD (poly[bis(4-phenyl)(4-butylphenyl)amine]), TCTA (4,4',4'-tris(carbazol-9-yl)triphenylamine), CBP (4,4'-bis(9-carbazolyl)biphenyl), etc.

[0056] The embodiment of the present application also provides a method for manufacturing a quantum dot light-emitting diode device. Figure 5 A method for manufacturing a positive-type structure of the quantum dot light-emitting diode device described in the embodiment of the present application is shown. As Figure 5 shown, the method for manufacturing a positive-type structure of the quantum dot light-emitting diode device includes the following steps:

[0057] S10. Prepare a quantum dot light-emitting layer 130 on an anode substrate (including a substrate 100 and an anode 110);

[0058] S20. Prepare a film layer 150 containing silver halide on the quantum dot light-emitting layer 130;

[0059] S30. Prepare an electron transport layer 140 on the film layer 150 containing silver halide;

[0060] S40. Prepare a cathode 120 on the electron transport layer 140 to obtain the quantum dot light-emitting diode device.

[0061] In some embodiments of the present application, the step S20 includes:

[0062] First deposit a silver salt solution on the quantum dot light-emitting layer 130, then deposit a halogen salt solution, and perform heat treatment to obtain a film layer 150 containing silver halide;

[0063] Or first deposit a halogen salt solution on the quantum dot light-emitting layer 130, then deposit a silver salt solution, perform heat treatment, and remove the solvent to obtain a film layer 150 containing silver halide. In this embodiment, the heat treatment is, for example, isothermal heat treatment. The purpose of the heat treatment is to remove the solvent molecules in the film layer 150 containing silver halide and avoid the residual solvent affecting the film-forming effect of the film layer 150 containing silver halide.

[0064] Figure 6 A method for manufacturing an inverted-type structure of the quantum dot light-emitting diode device described in the embodiment of the present application is shown. As Figure 6 shown, the method for manufacturing an inverted-type structure of the quantum dot light-emitting diode device includes the following steps:

[0065] S100. Prepare an electron transport layer 140 on a cathode substrate (including a substrate 100 and a cathode 120);

[0066] S200. Prepare a film layer 150 containing silver halide on the electron transport layer 140;

[0067] S300. Prepare a quantum dot light-emitting layer 130 on the film layer 150 containing silver halide;

[0068] S400. Prepare an anode 110 on the quantum dot light-emitting layer 130 to obtain the quantum dot light-emitting diode device.

[0069] In some embodiments of the present application, the step S200 includes:

[0070] Deposit a silver salt solution on the electron transport layer 140 first, then deposit a halogen salt solution, and perform heat treatment to obtain a film layer 150 containing silver halide;

[0071] Or deposit a halogen salt solution on the electron transport layer 140 first, then deposit a silver salt solution, and perform heat treatment to remove the solvent to obtain a film layer 150 containing silver halide. In this embodiment, the heat treatment is, for example, isothermal heat treatment. The purpose of the heat treatment is to remove the solvent molecules in the film layer 150 containing silver halide to avoid the residual solvent affecting the film-forming effect of the film layer 150 containing silver halide.

[0072] Whether in the preparation method of a quantum dot light-emitting diode device with a normal structure or in the preparation method of a quantum dot light-emitting diode device with an inverted structure, in the step of preparing the film layer 150 containing silver halide, the order of spin-coating the silver salt solution and spin-coating the halogen salt solution can be interchanged. Spin-coating the halogen salt solution first and then the silver salt solution can coordinate the halogen salt solution with the quantum dots, thereby passivating the defects on the surface of the quantum dots.

[0073] Unless otherwise specified, the relevant descriptions of the following embodiments are applicable to both the preparation method of a quantum dot light-emitting diode device with a normal structure and the preparation method of a quantum dot light-emitting diode device with an inverted structure.

[0074] In some embodiments of the present application, the quantum dot light-emitting layer 130 includes blue-light quantum dots, green-light quantum dots or red-light quantum dots. The blue-light quantum dots include at least one of CdZnS, CdZnSe, CdS / ZnS, CdZnS / ZnS, CdZnSe / ZnSe / ZnS, CdZnSe / ZnSe / CdZnS, ZnSeTe / ZnSe / ZnS, ZnSTe / ZnSe / ZnS, ZnSeTe / ZnS, CsPbCl3 and CsPbCl2Br. The green-light quantum dots include at least one of CdZnSeS, CdZnSeS / ZnSe / ZnS, CdZnSe / ZnS, CdZnSe / CdS, CdZnSe / ZnSe / ZnS, ZnSeTe / ZnSe / ZnS, ZnSeTe / ZnS InP / ZnS, InP / ZnSe / ZnS and CsPbBr3. The red-light quantum dots include at least one of CdSeS, CdZnSeS, CdZnSeS / ZnSe, CdZnSeS / ZnS, CdSe / ZnS, CdZnSe / CdZnSe / ZnS, CdZnSe / CdZnSe / ZnSe / ZnS, InP / ZnS, InP / ZnSe / ZnS, CsPbI3, CuInS2 / ZnSe / ZnS and CuInS2 / ZnS. It can be understood that some of the specific components of the above blue-light quantum dots, red-light quantum dots and green-light quantum dots are the same, because the emission wavelength of the quantum dots is jointly determined by their particle size and composition. Under the same material structure, by changing the particle size of the quantum dots and / or the composition ratio of the quantum dots, the wavelength of the quantum dots can be regulated, and then quantum dots with corresponding wavelengths can be obtained.

[0075] In some embodiments of the present application, the silver salt is a soluble silver salt, for example, it can be silver nitrate or silver fluoride.

[0076] In some embodiments of the present application, the halogen salt can be a soluble chloride salt, such as magnesium chloride, calcium chloride, ammonium chloride, sodium chloride or zinc chloride, or a soluble bromide salt, such as ammonium bromide, sodium bromide or potassium bromide, or a soluble iodide salt, such as ammonium iodide, sodium iodide or potassium iodide.

[0077] In some embodiments of the present application, the silver salt solution can be, for example, an aqueous silver salt solution, that is, the solvent is water; or it can be a silver salt ethanol solution, that is, the solvent is an ethanol solution (i.e., ethanol and water). The ethanol solution is, for example, 90 weight (wt)%. The purity of the ethanol solution should not be too high, otherwise the silver salt is difficult to dissolve. The purity of the ethanol solution should not be too low, otherwise the ethanol contains a large amount of water and the surface tension of the solution is too large. During the spin-coating process, it is difficult for the solution to spread out, which is not conducive to film formation.

[0078] In some embodiments of the present application, the halogen salt solution can be, for example, an aqueous solution of a halogen salt, i.e., the solvent is water; or it can be an ethanol solution of a halogen salt, i.e., the solvent is an ethanol solution (i.e., ethanol and water). The ethanol solution is, for example, 90% by weight (wt)%. The purity of the ethanol solution should not be too high, otherwise the halogen salt is difficult to dissolve. The purity of the ethanol solution should not be too low either, otherwise the ethanol contains a large amount of water, and the surface tension of the solution is too large, making it difficult for the solution to spread during the spin-coating process and being unfavorable for film formation.

[0079] In some embodiments of the present application, the concentration of the silver salt in the silver salt solution is 10 to 100 milligrams per milliliter (g / mL). If the concentration of the silver salt is too low, the subsequent formed film layer 150 containing silver halide is too thin, and the absorption effect on visible light is not good. If the concentration of the silver salt is too high, the film layer 150 containing silver halide is too thick, increasing the difficulty of electron injection into the quantum dot light-emitting layer 130, resulting in an increase in the operating voltage of the device and being unfavorable for improving the device performance. It can be understood that the concentration of the silver salt in the silver salt solution can take any value within 10 mg / mL to 100 mg / mL, such as 10 mg / mL, 20 mg / mL, 30 mg / mL, 40 mg / mL, 50 mg / mL, 60 mg / mL, 70 mg / mL, 80 mg / mL, 90 mg / mL, 100 mg / mL, etc. In some embodiments of the present application, the concentration of the silver salt in the silver salt solution is 20 g / mL to 50 g / mL.

[0080] In some embodiments of the present application, the concentration of the halogen salt in the halogen salt solution is 10 g / mL to 100 g / mL. If the concentration of the halogen salt is too low, the subsequent formed film layer 150 containing silver halide is too thin, and the absorption effect on visible light is not good. If the concentration of the halogen salt is too high, a large amount of halogen salt remains unreacted, making it difficult to clean and remove impurities with ethanol subsequently. It can be understood that the concentration of the silver salt in the halogen salt solution can take any value within 10 mg / mL to 100 mg / mL, such as 10 mg / mL, 20 mg / mL, 30 mg / mL, 40 mg / mL, 50 mg / mL, 60 mg / mL, 70 mg / mL, 80 mg / mL, 90 mg / mL, 100 mg / mL, etc. In some embodiments of the present application, the concentration of the halogen salt in the halogen salt solution is 10 g / mL to 50 g / mL.

[0081] In various embodiments of the present application, the preparation method of each film layer can be a chemical method or a physical method. The chemical methods include, but are not limited to, chemical solution deposition methods (including sol-gel method and metal organic chemical vapor deposition), chemical vapor deposition method, co-precipitation method, and electrochemical deposition method, one or more of which; the physical methods include, but are not limited to, solution methods (such as spin coating method, printing method, doctor blade method, dip coating method, immersion method, spraying method, roll coating method, casting method, slot die coating method or bar coating method, etc.), evaporation methods (such as thermal evaporation method, electron beam evaporation method, magnetron sputtering method or multi-arc ion plating method, etc.), deposition methods (such as physical vapor deposition method, atomic layer deposition method, pulsed laser deposition method, etc.), one or more of which. Hereinafter, taking the spin coating method for preparing each film layer as an example for illustration.

[0082] In some embodiments of the present application, the spin coating speeds of the silver salt solution and the halide salt solution are both 1000 to 5000 revolutions per minute (r / m or rpm). If the spin coating speed is too low, the film layer 150 containing silver halide is too thick, which increases the difficulty of electron injection into the quantum dots, the operating voltage of the device is high, and it is not conducive to improving the device performance; if the spin coating speed is too high, the film layer 150 containing silver halide is too thin, the absorption performance of visible light decreases, more photo-generated holes are formed in the electron transport layer 140, the surface of the quantum dots is easily damaged, and the device performance deteriorates. In some other embodiments of the present application, the spin coating speeds of the silver salt solution and the halide salt solution are both 2000 rpm to 3000 rpm. In some embodiments of the present application, the spin coating times of the silver salt solution and the halide salt solution are both 30 s to 90 s. If the spin coating time is too short, the film contains a large amount of unevaporated solvent, the mobility of silver ions and halide ions is large, the thickness of the formed silver halide is uneven, and the film forming effect is poor. If the spin coating time is too long, the production efficiency decreases. In some other embodiments of the present application, the spin coating times of the silver salt solution and the halide salt solution are both 30 s to 60 s.

[0083] In some embodiments of the present application, in the step of preparing the film layer 150 containing silver halide, the temperature of the heat treatment is 80 °C to 150 °C. If the temperature of the heat treatment is too low, it is difficult to completely remove the solvent molecules. If the temperature of the heat treatment is too high, the energy consumption increases. In some other embodiments of the present application, in the step of preparing the film layer 150 containing silver halide, the temperature of the heat treatment is 80 °C to 120 °C. In some embodiments of the present application, in the step of preparing the film layer 150 containing silver halide, the time of the heat treatment is 10 min to 60 min. If the time of the heat treatment is too short, it is difficult to completely remove the solvent molecules. If the time of the heat treatment is too long, the device preparation cycle becomes longer, which is not conducive to production. In some other embodiments of the present application, in the step of preparing the film layer 150 containing silver halide, the time of the heat treatment is 20 min to 30 min.

[0084] In some embodiments of the present application, the step of preparing the quantum dot light-emitting layer 130 includes spin-coating a quantum dot solution and performing heat treatment to obtain the quantum dot light-emitting layer 130.

[0085] In some embodiments of the present application, the particle size of the quantum dots is 8 to 15 nanometers (nm). If the particle size of the quantum dots is too small, the film-forming property of the quantum dot material becomes poor, and the energy resonance transfer effect between quantum dot particles is significant, which is not conducive to the application of the material. If the particle size of the quantum dots is too large, the quantum effect of the quantum dot material weakens, resulting in a decline in the optoelectronic performance of the material.

[0086] In some embodiments of the present application, the concentration of the quantum dot solution is 10 mg / mL to 50 mg / mL. The solvent in the quantum dot solution can be, for example, n-octane, which is prepared by dissolving quantum dots in n-octane. If the concentration of the solution is too low, the quantum dot light-emitting layer 130 in the device is too thin, and the brightness of the device is weak. If the concentration of the quantum dot solution is too high, the quantum dot light-emitting layer 130 is too thick, and the internal resistance of the device increases, which is not conducive to improving the device performance. It can be understood that the concentration of the quantum dot solution can take any value within 10 mg / mL to 50 mg / mL, for example: 10 mg / mL, 15 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL, 35 mg / mL, 40 mg / mL, 45 mg / mL, 50 mg / mL, etc. In some other embodiments of the present application, the concentration of the quantum dot solution is 10 mg / mL to 30 mg / mL.

[0087] In some embodiments of the present application, the spin-coating speed of the quantum dot solution is 1000 rpm to 5000 rpm. If the spin-coating speed is too low, the internal resistance of the quantum dot light-emitting layer 130 and the device increases, which is not conducive to improving the performance of the optoelectronic device. If the spin-coating speed is too high, the quantum dot light-emitting layer 130 in the device has a relatively low brightness. In some embodiments of the present application, the spin-coating speed of the quantum dot solution is 2000 rpm to 3000 rpm. In some other embodiments of the present application, the spin-coating time of the quantum dot solution is 30 s to 90 s. If the time is too short, the quantum dot light-emitting layer 130 contains a large amount of unevaporated solvent, and during the subsequent drying process, the quantum dot light-emitting layer 130 is easily damaged and the film-forming effect is poor. If the spin-coating time is too long, the production efficiency decreases. In some other embodiments of the present application, the spin-coating time of the quantum dot solution is 30 s to 60 s.

[0088] In some embodiments of the present application, in the step of preparing the quantum dot light-emitting layer 130, the temperature of the heat treatment is 80°C to 150°C. The purpose of the heat treatment is to remove the solvent molecules in the quantum dot light-emitting layer 130 to avoid the remaining solvent affecting the film-forming effect of the quantum dot light-emitting layer 130. If the temperature of the heat treatment is too low, the solvent molecules are difficult to be completely removed. If the temperature is too high, the film structure of the quantum dot light-emitting layer 130 is easily damaged, affecting the optoelectronic performance of the device. In some other embodiments of the present application, in the step of preparing the quantum dot light-emitting layer 130, the temperature of the heat treatment is 100°C to 120°C. In some embodiments of the present application, in the step of preparing the quantum dot light-emitting layer 130, the time of the heat treatment is 10 min to 60 min. If the time is too short, the solvent molecules are difficult to be completely removed. If the time is too long, the device preparation cycle becomes longer, which is not conducive to production. In some other embodiments of the present application, in the step of preparing the quantum dot light-emitting layer 130, the time of the heat treatment is 20 min to 40 min.

[0089] In some embodiments of the present application, the step of preparing the electron transport layer 140 includes spin-coating a dispersion of an electron transport material and performing a heat treatment to obtain the electron transport layer 140. The heat treatment is, for example, a constant-temperature heat treatment. The dispersion of the electron transport material can be an ethanol dispersion of the electron transport material, such as an N-type nanometal oxide ethanol dispersion.

[0090] In some embodiments of the present application, the concentration of the electron transport material in the dispersion of the electron transport material is 10 mg / mL to 30 mg / mL. If the concentration of the electron transport material is too low, the electron transport layer 140 in the optoelectronic device is too thin. If the concentration of the electron transport material is too high, the electron transport layer 140 is thick. Whether the electron transport layer 140 is too thin or too thick will cause an imbalance between electrons and holes inside the device, thereby deteriorating the device performance. It can be understood that the concentration of the electron transport material can take any value within 10 mg / mL to 30 mg / mL, such as 10 mg / mL, 15 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL, etc.

[0091] In some embodiments of the present application, the spin coating speed of the dispersion of the spin-coated electron transport material is 1000 rpm to 5000 rpm per minute. If the spin coating speed is too low, the electron transport layer 140 will be too thick. If the spin coating speed is too high, the electron transport layer 140 will be too thin. Whether the electron transport layer 140 in the device is too thin or too thick will cause imbalance between electrons and holes inside the device, thereby deteriorating the device performance. In some other embodiments of the present application, the spin coating speed of the dispersion of the spin-coated electron transport material is 2000 rpm to 3000 rpm. In some embodiments of the present application, the spin coating time of the dispersion of the spin-coated electron transport material is 30 s to 90 s. If the spin coating time is too short, a large amount of solvent in the electron transport layer 140 will not volatilize. During the subsequent drying process, the electron transport layer 140 will be damaged and the film forming effect will be poor. If the spin coating time is too long, the production efficiency will decrease. In some other embodiments of the present application, the spin coating time of the dispersion of the spin-coated electron transport material is 30 s to 60 s.

[0092] In some embodiments of the present application, in the step of preparing the electron transport layer 140, the temperature of the heat treatment is 80 °C to 150 °C. The purpose of the heat treatment is to remove the solvent molecules in the electron transport layer 140 to avoid the remaining solvent affecting the film forming effect of the electron transport layer 140. If the temperature of the heat treatment is too low, it is difficult to completely remove the solvent molecules. If the temperature of the heat treatment is too high, the energy consumption will increase. In some other embodiments of the present application, in the step of preparing the electron transport layer 140, the temperature of the heat treatment is 80 °C to 100 °C. In some embodiments of the present application, in the step of preparing the electron transport layer 140, the time of the heat treatment is 10 min to 60 min. If the time of the heat treatment is too short, it is difficult to completely remove the solvent molecules. If the time of the heat treatment is too long, the device preparation cycle will become longer, which is not conducive to production. In some other embodiments of the present application, in the step of preparing the electron transport layer 140, the time of the heat treatment is 20 min to 30 min.

[0093] In some embodiments of the present application, the step of preparing the cathode 120 includes: evaporating a metal material by means of vacuum thermal evaporation. The evaporation step includes: under a vacuum environment, bombarding and heating the metal material with an electron beam. The metal material is evaporated into an atomic state under the action of electron beam bombardment heating. The atomic vapor moves freely and collides with the surface of the substrate with a lower temperature and condenses to form a thin film.

[0094] In some embodiments of the present application, the current for electron beam bombardment heating is 100 to 250 amperes (A). If the current of electron beam bombardment is too small, it is difficult for the metal material to evaporate and the evaporation coating is difficult to perform. If the current of electron beam bombardment is too high, there will be a large amount of metal atom vapor in the vacuum chamber, the evaporation coating process proceeds rapidly, the flatness of the metal electrode film decreases, affecting the electrode and the hole transport layer 160, and is not conducive to the transport of carriers in the device. In some other embodiments of the present application, the current for electron beam bombardment heating is 100 A to 150 A.

[0095] In some embodiments of the present application, the thickness of the cathode 120 is 20 nm to 200 nm. If the cathode 120 is too thin, the electrode is easily damaged, affecting the use of the device. If the cathode 120 is too thick, the raw material consumption increases, the evaporation coating time is prolonged, and the production cost increases. In some other embodiments of the present application, the thickness of the cathode 120 is 50 nm to 80 nm.

[0096] In some embodiments of the present application, the method for preparing the quantum dot light-emitting diode device further includes the step of preparing the hole transport layer 160. Specifically, the step of preparing the hole transport layer 160 includes: spin-coating a hole transport material and performing heat treatment to obtain the hole transport layer 160.

[0097] In some embodiments of the present application, the rotation speed of spin-coating the hole transport material is 1000 rpm to 5000 rpm. If the spin-coating speed is too low, the hole transport layer 160 is too thick. If the spin-coating speed is too high, the hole transport layer 160 is too thin. Whether the hole transport layer 160 is too thin or too thick will cause an imbalance between electrons and holes inside the device, thereby deteriorating the device performance. In some other embodiments of the present application, the rotation speed of spin-coating the hole transport material is 2000 rpm to 3000 rpm. In some embodiments of the present application, the spin-coating time of the hole transport material is 30 s to 90 s. If the spin-coating time is too short, the solvent in the hole transport layer 160 has not volatilized, and the film-forming effect of the hole transport layer 160 is poor during the subsequent drying process. If the spin-coating time is too long, the production efficiency decreases. In some embodiments of the present application, the spin-coating time of the hole transport material is 30 s to 60 s.

[0098] In some embodiments of the present application, the concentration of the hole transport material solution is 10 mg / mL to 50 mg / mL. The hole transport material solution is, for example, a TFB dichlorobenzene solution with a concentration of 10 mg / mL to 50 mg / mL, which is prepared by dissolving TFB in a dichlorobenzene solvent. If the concentration of the hole transport material solution is too low, the hole transport layer 160 in the device is too thin. If the concentration of the hole transport material solution is too high, the hole transport layer 160 is too thick. Whether the hole transport layer 160 is too thin or too thick will cause an imbalance between electrons and holes inside the device, thereby deteriorating the performance of the device. It can be understood that the concentration of the hole transport material solution can take any value within 10 mg / mL to 50 mg / mL, such as 10 mg / mL, 20 mg / mL, 30 mg / mL, 40 mg / mL, 50 mg / mL, etc. In some other embodiments of the present application, the concentration of the hole transport material solution is 10 mg / mL to 20 mg / mL.

[0099] In some embodiments of the present application, in the step of preparing the hole transport layer 160, the temperature of the heat treatment is 50 °C to 150 °C. The purpose of the heat treatment is to remove the solvent molecules in the hole transport layer 160 to avoid the residual solvent affecting the film-forming effect. If the temperature of the heat treatment is too low, the solvent molecules are difficult to be completely removed. If the temperature of the heat treatment is too high, it is easy to damage the film structure of the functional layer of the optoelectronic quantum dot light-emitting diode device, affecting the optoelectronic performance of the device. In some other embodiments of the present application, in the step of preparing the hole transport layer 160, the temperature of the heat treatment is 80 °C to 120 °C. In some embodiments of the present application, in the step of preparing the hole transport layer 160, the time of the heat treatment is 10 min to 60 min. If the heat treatment time is too short, the solvent molecules are difficult to be completely removed. If the heat treatment time is too long, it is easy to damage the film structure of the functional layer of the device, affecting the optoelectronic performance of the device. In some other embodiments of the present application, in the step of preparing the hole transport layer 160, the time of the heat treatment is 20 min to 40 min.

[0100] The present invention will be described in detail below by way of examples.

[0101] Example 1

[0102] This example provides a method for preparing an optoelectronic quantum dot light-emitting diode device, including the following steps:

[0103] (1) providing an ITO glass substrate (i.e., an anode substrate) and a 10 mg / mL TFB dichlorobenzene solution, taking 0.2 mL of the TFB dichlorobenzene solution, dropping it onto the top of the ITO glass substrate, and spin coating it at a speed of 3000 rpm for 30 seconds, heating the spin-coated wafer to 80° C., and heat treating it for 30 minutes to remove the remaining solvent, thereby completing the preparation of the hole transport layer 160;

[0104] (2) Fix the substrate after spin coating the hole transport layer 160 obtained in (1) above on a spin coater, take 0.1 mL of 30 mg / mL CdZnSe / ZnSe / ZnS blue light quantum dot n-octane solution, drop it on the hole transport layer 160, spin coat at 3000 rpm for 40 seconds, and after spin coating, transfer to a 110° C. hot plate and heat treat for 30 minutes to remove the residual solvent, thereby completing the preparation of the quantum dot light-emitting layer 130;

[0105] (3) The wafer was re-fixed on the spin coater, 0.2 mL of 30 mg / mL silver nitrate ethanol solution was taken and dropped onto the quantum dot light-emitting layer 130, and the solution was spin-coated at 3000 rpm for 40 s. Then, 0.2 mL of 30 mg / mL ammonium chloride solution was taken and spin-coated at 3000 rpm for 40 s. After the ammonium chloride solution was spin-coated, 0.2 mL of ethanol was taken at 2000 rpm and dropped onto the center of the wafer to clean the silver chloride film. The process was repeated twice. After the cleaning was completed, the wafer was transferred to a 100° C. hot plate and heat-treated for 20 min to remove the residual solvent, thereby completing the preparation of the silver chloride layer (i.e., the film layer 150 containing silver halide);

[0106] (4) The wafer was re-fixed on the spin coater, 0.1 mL of 20 mg / mL nano zinc oxide ethanol solution was added dropwise to the top of the silver chloride layer, and the solution was spin-coated at 2000 rpm for 45 seconds. After the spin coating was completed, the wafer was transferred to a 100° C. hot plate and heat-treated for 30 minutes to remove the remaining solvent, thereby completing the preparation of the electron transport layer 140;

[0107] (5) The wafer is transferred to a vapor deposition machine, and an electron beam with a current of 35A is used to bombard the silver element to evaporate the silver element into atomic vapor, forming a 100nm thick silver electrode (i.e., cathode 120) above the electron transport layer 140, and then encapsulated to obtain the final optoelectronic device.

[0108] Example 2

[0109] This embodiment provides a method for preparing a quantum dot light-emitting diode device, comprising the following steps:

[0110] (1) providing an ITO glass substrate (i.e., an anode substrate) and a 10 mg / mL TFB dichlorobenzene solution, taking 0.2 mL of the TFB dichlorobenzene solution, dropping it onto the top of the ITO glass substrate, and spin coating it at a speed of 3000 rpm for 30 seconds, heating the spin-coated wafer to 80° C., and heat treating it for 30 minutes to remove the remaining solvent, thereby completing the preparation of the device hole transport layer 160;

[0111] (2) Fix the substrate after spin coating the hole transport layer 160 in (1) on a spin coater, take 0.1 mL of 30 mg / mL CdZnSe / ZnSe / ZnS blue light quantum dot n-octane solution, drop it on the hole transport layer 160, and spin coat at 3000 rpm for 40 seconds. After the spin coating is completed, transfer the wafer to a 110° C. hot plate and heat treat for 30 minutes to remove the residual solvent, thereby completing the preparation of the quantum dot light-emitting layer 130;

[0112] (3) The wafer was re-fixed on the spin coater, 0.2 mL of 30 mg / mL silver nitrate ethanol solution was taken and dropped onto the quantum dot light-emitting layer 130, and the solution was spin-coated at 3000 rpm for 40 s. Then, 0.2 mL of 30 mg / mL ammonium bromide solution was taken and spin-coated at 3000 rpm for 40 s. After the ammonium bromide solution was spin-coated, 0.2 mL of ethanol was taken at 2000 rpm and dropped onto the center of the wafer to clean the silver bromide film. The process was repeated twice. After the cleaning was completed, the wafer was transferred to a 100° C. hot plate and heat-treated for 20 min to remove the residual solvent, thereby completing the preparation of the silver bromide layer (i.e., the film layer 150 containing silver halide);

[0113] (4) The wafer was re-fixed on the spin coater, 0.1 mL of 20 mg / mL nano zinc oxide ethanol solution was added dropwise to the top of the silver bromide layer, and the solution was spin-coated at 2000 rpm for 45 s. After the spin coating was completed, the wafer was transferred to a 100° C. hot plate and heat-treated for 30 min to remove the remaining solvent, thereby completing the preparation of the electron transport layer 140;

[0114] (5) The wafer is transferred to a vapor deposition machine, and an electron beam with a current of 35A is used to bombard the silver element to evaporate the silver element into atomic vapor, forming a 100nm thick silver electrode (i.e., cathode 120) above the electron transport layer 140, and then encapsulated to obtain the final optoelectronic device.

[0115] Example 3

[0116] This embodiment provides a method for preparing a quantum dot light-emitting diode device, comprising the following steps:

[0117] (1) providing an ITO glass substrate (i.e., an anode substrate) and a 10 mg / mL TFB dichlorobenzene solution, taking 0.2 mL of the TFB dichlorobenzene solution, dropping it onto the top of the ITO glass substrate, and spin coating it at a speed of 3000 rpm for 30 seconds, heating the spin-coated wafer to 80° C., and heat treating it for 30 minutes to remove the remaining solvent, thereby completing the preparation of the hole transport layer 160;

[0118] (2) Fix the substrate after spin coating the hole transport layer 160 in (1) above on a spin coater, take 0.1 mL of 30 mg / mL CdZnSe / ZnSe / ZnS blue light quantum dot n-octane solution, drop it on the hole transport layer 160, and spin coat it at 3000 rpm for 40 seconds. After the spin coating is completed, transfer the wafer to a 110° C. hot plate and heat treat it for 30 minutes to remove the residual solvent, thereby completing the preparation of the quantum dot light-emitting layer 130;

[0119] (3) The wafer was re-fixed on the spin coater, 0.2 mL of 30 mg / mL silver nitrate ethanol solution was taken and dropped onto the quantum dot light-emitting layer 130, and the solution was spin-coated at 3000 rpm for 40 s. Then, 0.2 mL of 30 mg / mL ammonium iodide solution was taken and spin-coated at 3000 rpm for 40 s. After the ammonium iodide was spin-coated, 0.2 mL of ethanol was taken at 2000 rpm and dropped into the center of the wafer to clean the silver iodide film. The process was repeated twice. After the cleaning was completed, the wafer was transferred to a 100° C. hot plate and heat-treated for 20 min to remove the solvent, thereby completing the preparation of the silver iodide layer (i.e., the film layer 150 containing silver halide);

[0120] (4) Then, the wafer was re-fixed on the spin coater, 0.1 mL of 20 mg / mL nano zinc oxide ethanol solution was taken and dropped onto the silver iodide layer, and the solution was spin-coated at 2000 rpm for 45 seconds. After the spin coating was completed, the wafer was transferred to a 100° C. hot plate and heat-treated for 30 minutes to remove the remaining solvent, thereby completing the preparation of the electron transport layer 140;

[0121] (5) The wafer is transferred to a vapor deposition machine, and an electron beam with a current of 35A is used to bombard the silver element to evaporate the silver element into atomic vapor, forming a 100nm thick silver electrode (i.e., cathode 120) above the electron transport layer 140, and then encapsulated to obtain the final optoelectronic device.

[0122] Example 4

[0123] This embodiment provides a method for preparing a quantum dot light-emitting diode device, comprising the following steps:

[0124] (1) providing an ITO glass substrate (i.e., anode substrate) and a 10 mg / mL TFB dichlorobenzene solution. Taking 0.2 mL of the TFB dichlorobenzene solution, dripping it onto the top of the ITO glass substrate, and spin coating it at 3000 rpm for 30 seconds. After the spin coating, the wafer was heated to 80° C. and heat treated for 30 minutes to remove the remaining solvent, thereby completing the preparation of the hole transport layer 160;

[0125] (2) Fix the conductive glass after spin coating the hole transport layer 160 in (1) above on a spin coater, take 0.1 mL of 30 mg / mL CdZnSe / ZnSe / ZnS blue light quantum dot n-octane solution, drop it on the hole transport layer 160, and spin coat at 3000 rpm for 40 seconds. After the spin coating is completed, transfer the wafer to a 110°C heating plate and heat treat for 30 minutes to remove the residual solvent, thereby completing the preparation of the device quantum dot light-emitting layer 130;

[0126] (3) The wafer was re-fixed on the spin coater, 0.2 mL of 30 mg / mL ammonium chloride ethanol solution was taken and dropped onto the quantum dot light-emitting layer 130, and the solution was spin-coated at 3000 rpm for 40 s. Then, 0.2 mL of 30 mg / mL silver nitrate solution was taken and spin-coated at 3000 rpm for 40 s. After the silver nitrate was spin-coated, 0.2 mL of ethanol was taken at 2000 rpm and dropped into the center of the wafer to clean the silver chloride film. The process was repeated twice. After the cleaning was completed, the wafer was transferred to a 100° C. hot plate and heat-treated for 20 min to remove the solvent, thereby completing the preparation of the silver chloride layer (i.e., the film layer 150 containing silver halide);

[0127] (4) The wafer was re-fixed on the spin coater, 0.1 mL of 20 mg / mL nano zinc oxide ethanol solution was added dropwise to the top of the silver chloride layer, and the solution was spin-coated at 2000 rpm for 45 s. After the spin coating was completed, the wafer was transferred to a 100° C. hot plate and heat-treated for 30 min to remove the remaining solvent, thereby completing the preparation of the electron transport layer 140;

[0128] (5) The wafer is transferred to a vapor deposition machine, and an electron beam with a current of 35A is used to bombard the silver element to evaporate the silver element into atomic vapor, forming a silver electrode with a thickness of 100 nm above the hole transport layer 160, and then encapsulating the resulting photoelectric device.

[0129] Example 5

[0130] This embodiment provides a method for preparing a quantum dot light-emitting diode device, comprising the following steps:

[0131] (1) providing an ITO glass substrate (i.e., an anode substrate) and a 10 mg / mL TFB dichlorobenzene solution, taking 0.2 mL of the TFB dichlorobenzene solution, dropping it onto the top of the ITO glass substrate, and spin coating it at a speed of 3000 rpm for 30 seconds, heating the spin-coated wafer to 80° C., and heat treating it for 30 minutes to remove the remaining solvent, thereby completing the preparation of the hole transport layer 160;

[0132] (2) Fix the conductive glass after spin coating the hole transport layer 160 in (1) above on a spin coater, take 0.1 mL of 30 mg / mL CdZnSe / ZnSe / ZnS blue light quantum dot n-octane solution, drop it on the hole transport layer 160, and spin coat at 3000 rpm for 40 seconds. After the spin coating is completed, transfer the wafer to a 110° C. hot plate and heat treat for 30 minutes to remove the residual solvent, thereby completing the preparation of the quantum dot light-emitting layer 130;

[0133] (3) The sheet was re-fixed on the spin coater, 0.2 mL of 30 mg / mL silver fluoride ethanol solution was taken and dripped onto the top of the quantum dot light-emitting layer 130, and spin-coated at 3000 rpm for 40 s. Then, 0.2 mL of 30 mg / mL ammonium chloride solution was taken and spin-coated at 3000 rpm for 40 s. After the ammonium chloride spin coating was completed, 0.2 mL of ethanol was taken at 2000 rpm and dripped into the center of the sheet to clean the silver chloride film. This was repeated twice.

[0134] After cleaning, the wafer is transferred to a 100° C. hot plate and heat treated for 20 min to remove the solvent and complete the preparation of the silver chloride layer (i.e., the film layer 150 containing silver halide);

[0135] (4) The wafer was re-fixed on the spin coater, 0.1 mL of 20 mg / mL nano zinc oxide ethanol solution was added dropwise to the top of the silver chloride layer, and the solution was spin-coated at 2000 rpm for 45 s. After the spin coating was completed, the wafer was transferred to a 100° C. hot plate and heat-treated for 30 min to remove the remaining solvent, thereby completing the preparation of the electron transport layer 140;

[0136] (5) The wafer is transferred to a vapor deposition machine, and an electron beam with a current of 35A is used to bombard the silver element to evaporate the silver element into atomic vapor, forming a 100nm thick silver electrode (i.e., cathode 120) above the electron transport layer 140, and then encapsulated to obtain the final optoelectronic device.

[0137] Comparative Example

[0138] This comparative example provides a method for preparing a quantum dot light-emitting diode device. The difference between this comparative example and Example 4 is that: in the method for preparing the quantum dot light-emitting diode device of this comparative example, step (3) in the preparation method of Example 4 is not included, that is, the preparation step of the silver chloride layer is not included in this comparative example, while other steps and parameter conditions are the same as those in Example 4. Correspondingly, the quantum dot light-emitting diode device prepared in this comparative example does not include a silver chloride layer.

[0139] In order to illustrate the influence of adding a film layer 150 containing silver halide between the quantum dot light-emitting layer 130 and the electron transport layer 140 on the performance decay and quantum efficiency of the quantum dot light-emitting diode device, the time required for the brightness decay of 5% (T95) and the external quantum efficiency (EQE) of the quantum dot light-emitting diode devices prepared in Examples 1-5 and the comparative example were respectively investigated. The results are shown in Table 1.

[0140] Table 1

[0141]

[0142]

[0143] As can be seen from Table 1: after adding the film layer 150 containing silver halide to the quantum dot light-emitting diode device, the T95 performance of the quantum dot light-emitting diode device is significantly improved. This is because the film layer 150 containing silver halide effectively reduces the generation of photo-generated holes on the electron transport layer 140, avoids quenching caused by the oxidation of the ligands on the surface of the quantum dots, and thus improves the stability of the quantum dots; at the same time, after adding the film layer 150 containing silver halide to the quantum dot light-emitting diode device, the EQE of the quantum dot light-emitting diode device also shows better results. This is because the film layer 150 containing silver halide located between the electron transport layer 140 and the quantum dot light-emitting layer increases the difficulty of electron injection to a certain extent, making the charges inside the device more balanced and reducing the non-radiative recombination of electrons and holes; in addition, by comparing Example 4 with Example 1, it can be seen that the order of spin-coating the silver salt solution and the halogen salt solution can be interchanged, and spin-coating the halogen salt solution first and then the silver salt solution shows better results in terms of T95 performance and EQE performance than spin-coating the silver salt solution first and then the halogen salt solution. This is due to the coordination of the halogen salt solution with the quantum dots to passivate the defects on the surface of the quantum dots.

[0144] In summary, in the present application, a film layer 150 containing silver halide is added between the quantum dot light-emitting layer and the electron transport layer 140. Under the irradiation of short-wavelength light, the silver halide undergoes a decomposition reaction to form free silver atoms and halogen atoms. The silver atoms can effectively absorb visible light, greatly reducing the light irradiation intensity on the surface of the electron transport layer 140, inhibiting the generation of photo-generated holes in the electron transport layer 140, protecting the surface structure of the quantum dot material, slowing down the attenuation rate of the device performance, and by inhibiting the formation of photo-generated holes in the electron transport layer 140, the stability of the device can also be effectively improved, optimizing the lifetime performance of the device. At the same time, the newly added film layer 150 containing silver halide can also slow down the electron injection rate inside the device to a certain extent, which is beneficial to improving the unbalanced state of more electrons and fewer holes in the quantum dot light-emitting diode, reducing the charge accumulation inside the device, and enhancing the quantum efficiency of the device.

[0145] The above has introduced in detail a quantum dot light-emitting diode device and its preparation method provided by the embodiments of the present application. Specific examples are used herein to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A quantum dot light emitting diode device, characterized in that, It includes a cathode, an anode, and a stack disposed between the cathode and the anode. The stack includes a quantum dot light-emitting layer, an electron transport layer, and a silver halide-containing film layer disposed between the quantum dot light-emitting layer and the electron transport layer. The quantum dot light-emitting layer is disposed close to the anode, and the electron transport layer is disposed close to the cathode; Wherein, the silver halide-containing film layer is a silver halide layer, or the silver halide-containing film layer further includes a photocatalyst.

2. The quantum dot light-emitting diode device according to claim 1, wherein The silver halide is silver chloride, silver bromide, or silver iodide.

3. The quantum dot light emitting diode device according to claim 1, characterized in that, The quantum dot light-emitting layer includes blue light quantum dots, green light quantum dots, or red light quantum dots. The blue light quantum dots include at least one of CdZnS, CdZnSe, CdS / ZnS, CdZnS / ZnS, CdZnSe / ZnSe / ZnS, CdZnSe / ZnSe / CdZnS, ZnSeTe / ZnSe / ZnS, ZnSTe / ZnSe / ZnS, ZnSeTe / ZnS, CsPbCl3, and CsPbCl2Br. The green light quantum dots include at least one of CdZnSeS, CdZnSeS / ZnSe / ZnS, CdZnSe / ZnS, CdZnSe / CdS, CdZnSe / ZnSe / ZnS, ZnSeTe / ZnSe / ZnS, ZnSeTe / ZnS, InP / ZnS, InP / ZnSe / ZnS, and CsPbBr3. The red light quantum dots include at least one of CdSeS, CdZnSeS, CdZnSeS / ZnSe, CdZnSeS / ZnS, CdSe / ZnS, CdZnSe / CdZnSe / ZnS, CdZnSe / CdZnSe / ZnSe / ZnS, InP / ZnS, InP / ZnSe / ZnS, CsPbI3, CuInS2 / ZnSe / ZnS, and CuInS2 / ZnS.

4. A method for preparing a quantum dot light-emitting diode device, characterized in that, It includes the following steps: Prepare a quantum dot light-emitting layer on an anode substrate; Prepare a silver halide-containing film layer on the quantum dot light-emitting layer; Prepare an electron transport layer on the silver halide-containing film layer; Prepare a cathode on the electron transport layer to obtain the quantum dot light-emitting diode device; Or, prepare an electron transport layer on a cathode substrate; Prepare a silver halide-containing film layer on the electron transport layer; Prepare a quantum dot light-emitting layer on the silver halide-containing film layer; Prepare an anode on the quantum dot light-emitting layer to obtain the quantum dot light-emitting diode device; Wherein, the silver halide-containing film layer is a silver halide layer, or the silver halide-containing film layer further includes a photocatalyst.

5. The preparation method of the quantum dot light-emitting diode device according to claim 4, characterized in that, The step of preparing a silver halide-containing film layer on the quantum dot light-emitting layer includes: Deposit a silver salt solution first and then deposit a halogen salt solution, or deposit a halogen salt solution first and then deposit a silver salt solution; Or, the step of preparing a silver halide-containing film layer on the electron transport layer includes: Deposit a silver salt solution first and then deposit a halogen salt solution, or deposit a halogen salt solution first and then deposit a silver salt solution.

6. The method for preparing a quantum dot light-emitting diode device according to claim 5, characterized in that, The silver salt is a soluble silver salt, and the halogen salt is a soluble chloride salt, a soluble bromide salt, or a soluble iodide salt.

7. The method for preparing a quantum dot light-emitting diode device according to claim 6, wherein, The soluble silver salt is silver nitrate or silver fluoride; the soluble chloride salt is magnesium chloride, calcium chloride, ammonium chloride, sodium chloride, or zinc chloride; the soluble bromide salt is ammonium bromide, sodium bromide, or potassium bromide; the soluble iodide salt is ammonium iodide, sodium iodide, or potassium iodide.

8. The method for preparing a quantum dot light-emitting diode device according to claim 4, wherein The quantum dot light-emitting layer includes blue light quantum dots, green light quantum dots, or red light quantum dots. The blue light quantum dots include at least one of CdZnS, CdZnSe, CdS / ZnS, CdZnS / ZnS, CdZnSe / ZnSe / ZnS, CdZnSe / ZnSe / CdZnS, ZnSeTe / ZnSe / ZnS, ZnSTe / ZnSe / ZnS, ZnSeTe / ZnS, CsPbCl3, and CsPbCl2Br. The green light quantum dots include at least one of CdZnSeS, CdZnSeS / ZnSe / ZnS, CdZnSe / ZnS, CdZnSe / CdS, CdZnSe / ZnSe / ZnS, ZnSeTe / ZnSe / ZnS, ZnSeTe / ZnS, InP / ZnS, InP / ZnSe / ZnS, and CsPbBr3. The red light quantum dots include at least one of CdSeS, CdZnSeS, CdZnSeS / ZnSe, CdZnSeS / ZnS, CdSe / ZnS, CdZnSe / CdZnSe / ZnS, CdZnSe / CdZnSe / ZnSe / ZnS, InP / ZnS, InP / ZnSe / ZnS, CsPbI3, CuInS2 / ZnSe / ZnS, and CuInS2 / ZnS.

9. The method for preparing a quantum dot light-emitting diode device according to claim 5, wherein The concentration of the silver salt in the silver salt solution is 10 to 100 milligrams per milliliter, and the concentration of the halogen salt in the halogen salt solution is 10 to 100 milligrams per milliliter.

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