Quantum dot ink and electroluminescent device

Abstract

The application relates to the field of inkjet printing technology and discloses quantum dot ink and an electroluminescent device. The quantum dot ink comprises quantum dots and mixed polar solvents. The quantum dots comprise quantum dot bodies and organic chain segments connected to the surfaces of the quantum dot bodies, and the organic chain segments are linked with functional groups soluble in polar solvents. The mixed polar solvents comprise multiple polar solvents. The functional groups soluble in polar solvents are connected to the surfaces of the quantum dot bodies, so that the quantum dots can be dissolved in polar solvents. When the ink is printed on a TFB layer, the ink is compatible with the TFB layer, the interface compatibility between a quantum dot light-emitting layer formed after the ink is solidified and the TFB layer is high, the film surface of an electroluminescent device prepared by the application is uniform, and the electrical performance of the light-emitting layer formed by the ink is improved by adding zinc halide as an additive in the ink, so that the luminous brightness of the electroluminescent device is improved.

Description

Technical Field

[0001] This invention belongs to the field of inkjet printing technology, and particularly relates to a quantum dot ink and an electroluminescent device. Background Technology

[0002] Quantum dots, also known as semiconductor nanocrystals, are a novel type of semiconductor nanomaterial with sizes ranging from 1 to 10 nm. Due to quantum size and dielectric confinement effects, they possess unique photoluminescence (PL) and electroluminescence (EL) properties. Compared to traditional organic fluorescent dyes, quantum dots exhibit superior optical properties such as high quantum yield, high photochemical stability, resistance to photolysis, broad excitation and narrow emission range, high color purity, and the ability to adjust the emitted color by controlling the size of the luminescent nanoparticles. These properties make them promising candidates for applications in display technology, with quantum dot color filters being one of the most promising applications and a current research hotspot.

[0003] Currently, quantum dot color filters are typically fabricated using inkjet printing. The advantage of inkjet printing lies in its ability to control the position and size of the quantum dot ink droplets, thus enabling the printing of a film. Existing quantum dot inks are usually formulated by dispersing quantum dots in a non-polar solvent. In the fabrication of electroluminescent devices, the quantum dot ink is inkjet-printed onto a TFB layer (hole transport layer). Since the TFB layer is formed by spin-coating a polar polyaniline-based material, an interfacial effect exists at the interface between the TFB layer and the light-emitting layer after printing the aforementioned quantum dot ink onto the TFB layer to form the light-emitting layer. This results in uneven light emission from the film surface of the device.

[0004] Therefore, it is necessary to develop a new quantum dot ink that is compatible with TFB layers formed from polar polyaniline-based materials. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a quantum dot ink and an electroluminescent device, which ensures that the film surface of the electroluminescent device formed by the ink emits light uniformly.

[0006] According to a first aspect of the present invention, a quantum dot ink is provided, comprising quantum dots and a mixed polar solvent, wherein the quantum dot comprises a quantum dot body and organic segments attached to the surface of the quantum dot body, the organic segments being linked to functional groups soluble in the polar solvent; and the mixed polar solvent comprises a variety of polar solvents.

[0007] As a preferred embodiment of the aforementioned quantum dot ink, it further includes additives, said additives including zinc halide compounds;

[0008] Preferably, the zinc halide is selected from at least one of zinc chloride, zinc bromide, and zinc iodide;

[0009] Preferably, the zinc halide accounts for 1%-10% of the mass of the quantum dot ink.

[0010] As a preferred embodiment of the aforementioned quantum dot ink, the organic chain segment is derived from at least one of pentaerythritol tetra(3-mercaptopropionate), pentaerythritol tetra(3-mercaptobutyrate), and tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate;

[0011] Preferably, the functional group soluble in polar solvents includes at least one selected from ester, ether, hydroxyl, amino, and amide groups.

[0012] As a preferred embodiment of the aforementioned quantum dot ink, the quantum dots are obtained by reacting the quantum dot bulk with an organic compound dispersed in a solvent, wherein the organic compound contains functional groups soluble in polar solvents.

[0013] As a preferred embodiment of the aforementioned quantum dot ink, when the functional group soluble in the polar solvent includes an ester group, the organic compound includes one of ethyl acetate, methyl formate, and glyceryl stearate.

[0014] When the functional group soluble in polar solvents includes an ether group, the organic compound includes at least one of ethylene glycol butyl ether, dipropylene glycol methyl ether, propylene glycol ethyl ether, and propylene glycol butyl ether.

[0015] When the functional group soluble in polar solvents includes a hydroxyl group, the organic compound includes one of methanol, ethanol, ethylene glycol, glycerol, n-butanol, cyclohexanehexyl alcohol, benzyl alcohol, phenol, cresol, aminophenol, nitrophenol, naphthol, and chlorophenol.

[0016] When the functional group soluble in polar solvents includes an amine group, the organic compound includes one of dimethylamine, diethylamine, dipropylamine, dibutylamine, N-ethylmethylamine, and N-methyl-n-propylamine.

[0017] When the functional group soluble in polar solvents includes an amide group, the organic compound includes at least one of formamide, acetamide, propionamide, butyramide, or isobutyramide.

[0018] As a preferred embodiment of the aforementioned quantum dot ink, the solvent for dispersing the quantum dot bulk and the organic compound includes at least one of xylene, toluene, and trimethylbenzene.

[0019] As a preferred embodiment of the aforementioned quantum dot ink, the mixed polar solvent includes 3,5,5-trimethyl-1-hexanol, tripropylene glycol butyl ether, n-decyl alcohol, laurate methacrylate, and 4-tert-butylcyclohexyl acetate.

[0020] As a preferred embodiment of the aforementioned quantum dot ink, the quantum dot ink comprises, by mass fraction, 2%-3% of the quantum dots, 30%-32% of the 3,5,5-trimethyl-1-hexanol, 15%-17% of the tripropylene glycol butyl ether, 11%-13% of the n-decyl alcohol, 5%-7% of the laurate methacrylate, and 31%-33% of the 4-tert-butylcyclohexyl acetate.

[0021] As a preferred embodiment of the aforementioned quantum dot ink, the quantum dots are selected from blue cadmium-free and lead-free quantum dots.

[0022] According to a second aspect of the present invention, an electroluminescent device is provided, comprising an electron transport layer prepared from the aforementioned quantum dot ink.

[0023] Compared with the prior art, the present invention has at least the following advantages:

[0024] 1. This invention connects functional groups that are soluble in polar solvents to the surface of the quantum dot body, so that the quantum dots can be dissolved in polar solvents. When the ink is printed on the TFB layer, the ink is similarly miscible with the TFB layer. The interface compatibility between the quantum dot light-emitting layer and the TFB layer is high, and the light emission of the electroluminescent device formed is uniform.

[0025] 2. The present invention adds zinc halide as an additive to the ink to improve the electrical properties of the light-emitting layer formed by the ink, thereby improving the luminous brightness of the electroluminescent device. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Appendix Figure 1 A diagram showing the droplet size when printing the zinc oxide magnesium ink of the present invention using an inkjet printer;

[0028] Appendix Figure 2 A diagram showing the droplet state when printing the zinc oxide magnesium ink of the present invention using an inkjet printer;

[0029] Appendix Figure 3 A 100-dot verification image of the zinc oxide magnesium ink of the present invention printed using an inkjet printer;

[0030] Appendix Figure 4A waveform diagram of printing zinc oxide magnesium ink of the present invention using an inkjet printer;

[0031] Appendix Figure 5 This is a film surface view of the electroluminescent device in Example 1;

[0032] Appendix Figure 6 This is a film surface diagram of the electroluminescent device in Comparative Example 1. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be described in detail below. It should be noted that these embodiments are only partial, not complete.

[0034] As used herein, expressions such as "at least one" modify the entire list of elements without modifying any individual elements of the list when placed before or after it. Unless otherwise defined, all terms in this specification (including technical and scientific terms) are to be defined as commonly understood by one of ordinary skill in the art. Terms defined in common dictionaries should be interpreted as consistent with their meaning in the context of the relevant art and in this disclosure, and should not be interpreted ideally or overly broadly unless clearly defined. Furthermore, unless expressly stated to the contrary, the terms "comprising" and "including," when used in this specification, indicate the presence of the stated features, regions, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, regions, wholes, steps, operations, elements, components, and / or sets thereof. Therefore, the above terms should be understood to mean that the stated elements are included, but not that any other elements are excluded.

[0035] As used herein, the term “and / or” includes any and all combinations of one or more of the related listed items. The term “or” means “and / or”.

[0036] It will be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms.

[0037] As used herein, “about” or “approximately” includes the stated value and means within an acceptable range of deviation from the specific value, as determined by one of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the specific quantity (i.e., limitations of the measurement system). For example, “about” may mean a deviation from the stated value within one or more standard deviations, or within ±10%, ±5%.

[0038] As mentioned in the background section, existing quantum dot inks are usually formulated by dispersing quantum dots in a non-polar solvent. When fabricating electroluminescent devices, quantum dot ink is inkjet printed onto a TFB layer (hole transport layer). Since the TFB layer is formed by spin-coating a polar polyaniline-based material, after the quantum dot ink is printed onto the TFB layer to form the light-emitting layer, there is an interface effect at the interface between the TFB layer and the light-emitting layer, resulting in uneven light emission from the film surface of the device.

[0039] Based on this, a first aspect of the present invention provides a quantum dot ink, comprising quantum dots and a mixed polar solvent. The quantum dot comprises a quantum dot body and organic segments connected to the surface of the quantum dot body, the organic segments being linked to functional groups soluble in the polar solvent; the mixed polar solvent comprises a variety of polar solvents. The present invention connects functional groups soluble in polar solvents to the surface of the quantum dot body, enabling the quantum dots to dissolve in polar solvents (such as propylene glycol methyl ether acetate, diethylene glycol butyl ether acetate, diethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether, dipropylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, etc.). When this ink is printed on a TFB layer, the ink and the TFB layer are similarly miscible, resulting in high interfacial compatibility between the quantum dot luminescent layer and the TFB layer.

[0040] As a preferred embodiment of the present invention, the quantum dot ink further includes an additive, which includes a zinc halide compound. The inventors have discovered that adding zinc halide as an additive to the ink can improve the electrical properties of the light-emitting layer formed by the ink, further enhancing charge injection and charge transport between the light-emitting layer and the hole transport layer and electron transport layer, and significantly improving the conductivity of the electroluminescent device without affecting efficiency.

[0041] Preferably, the zinc halide is selected from at least one of zinc chloride, zinc bromide, and zinc iodide. As a preferred embodiment of the present invention, zinc chloride is added as an additive to the above-mentioned quantum dot ink. Zinc chloride has good solubility in polar solvents and exhibits a mild reaction.

[0042] Preferably, the zinc halide accounts for 1%-10% of the mass of the quantum dot ink. The inventors have found that when the content of zinc halide, especially zinc chloride, is less than 1%, it does not improve the electrical performance, and when it is more than 10%, it reduces the solubility and affects the surface of the light-emitting layer.

[0043] Regarding the design of functional groups soluble in polar solvents attached to the quantum dot matrix, in this invention, the organic chain segments are derived from at least one of pentaerythritol tetra(3-mercaptopropionate), pentaerythritol tetra(3-mercaptobutyrate), and tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate; the functional groups soluble in polar solvents include at least one of ester, ether, hydroxyl, amino, and amide groups. Specifically, the quantum dots of this invention with functional groups soluble in polar solvents are obtained by reacting the quantum dot matrix with an organic compound dispersed in a solvent, wherein the organic compound contains functional groups soluble in polar solvents.

[0044] In this invention, when the functional group soluble in polar solvents includes an ester group, the organic compound includes one of ethyl acetate, methyl formate, and glyceryl stearate.

[0045] When the functional group soluble in polar solvents includes an ether group, the organic compound includes at least one of ethylene glycol butyl ether, dipropylene glycol methyl ether, propylene glycol ethyl ether, and propylene glycol butyl ether.

[0046] When the functional group soluble in polar solvents includes a hydroxyl group, the organic compound includes one of methanol, ethanol, ethylene glycol, glycerol, n-butanol, cyclohexanehexyl alcohol, benzyl alcohol, phenol, cresol, aminophenol, nitrophenol, naphthol, and chlorophenol.

[0047] When the functional group soluble in polar solvents includes an amine group, the organic compound includes one of dimethylamine, diethylamine, dipropylamine, dibutylamine, N-ethylmethylamine, and N-methyl-n-propylamine.

[0048] When the functional group soluble in polar solvents includes an amide group, the organic compound includes at least one of formamide, acetamide, propionamide, butyramide, or isobutyramide.

[0049] As a preferred embodiment of the aforementioned quantum dot ink, the solvent for dispersing the quantum dot bulk and the organic compound includes at least one of xylene, toluene, and trimethylbenzene. Such solvents can better dissolve the quantum dot bulk and the organic compound, and promote efficient reaction.

[0050] As a preferred embodiment of the aforementioned quantum dot ink, the mixed polar solvents include 3,5,5-trimethyl-1-hexanol, tripropylene glycol butyl ether, n-decyl alcohol, laurate methacrylate, and 4-tert-butylcyclohexyl acetate. The boiling points of each polar solvent in this ink increase sequentially. During inkjet printing of this quantum dot ink, the polar solvents evaporate in a gradient, avoiding complete evaporation at once. This ensures the dispersion of quantum dots during film formation, thereby ensuring a smooth film surface on the device.

[0051] As a preferred embodiment of the aforementioned quantum dot ink, the quantum dot ink comprises, by mass fraction, 2%-3% of the quantum dots, 30%-32% of the 3,5,5-trimethyl-1-hexanol, 15%-17% of the tripropylene glycol butyl ether, 11%-13% of the n-decyl alcohol, 5%-7% of the laurate methacrylate, and 31%-33% of the 4-tert-butylcyclohexyl acetate. This formulation of polar solvents balances the solubility of quantum dots with the requirements of inkjet printing.

[0052] As a preferred embodiment of the aforementioned quantum dot ink, the quantum dots are selected from blue cadmium-free and lead-free quantum dots, such as: ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, HgZnTeS, HgZnSeS, HgZnSeTe, HgZnSTe, GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs. GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, InZnP, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb or combinations thereof, perovskite nanocrystals.

[0053] According to a second aspect of the present invention, an electroluminescent device is provided, comprising an electron transport layer prepared from the aforementioned quantum dot ink.

[0054] The present invention will be further described in detail below with reference to specific embodiments and comparative examples. However, the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use. The conditions not specified are conventional conditions in the industry.

[0055] Example 1

[0056] 1. Formulating quantum dot ink

[0057] Step S1: 100 mg of blue-light ZnSe quantum dots and 5 mg of pentaerythritol tetra(3-mercaptopropionate) were added to 1 ml of xylene and reacted at 80 °C under nitrogen atmosphere for 30 minutes. Then, 5 mg of succinate mono[2-[(2-methacryloyl)oxy]ethyl] ester was added and reacted at 120 °C for 60 minutes to obtain a modified ZnSe quantum dot solution. After vacuum drying to remove xylene, the modified ZnSe quantum dots were obtained. The modified ZnSe quantum dots were dissolved in toluene to prepare a 15 mg / ml ZnSe quantum dot solution.

[0058] Step S2: Take 2% ZnSe quantum dot solution, 31% 3,5,5-trimethyl-1-hexanol, 16% tripropylene glycol butyl ether, 12% n-decyl alcohol, 6% laurate methacrylate, 32% 4-tert-butylcyclohexyl acetate and 5% zinc chloride by mass percentage.

[0059] Step S3: Disperse zinc chloride in 3,5,5-trimethyl-1-hexanol and sonicate at room temperature for 2 hours until completely dissolved.

[0060] Step S4: After vacuum drying the ZnSe quantum dot solution to remove toluene, mix it with 3,5,5-trimethyl-1-hexanol, tripropylene glycol butyl ether, n-decyl alcohol, laurate methacrylate, and 4-tert-butylcyclohexyl acetate dissolved in zinc chloride. Stir at room temperature for 30 minutes until the ZnSe quantum dots are completely dissolved. Filter the solution three times using a 0.22µm filter and set aside.

[0061] 2. Fabrication of electroluminescent devices

[0062] S1. Provide a flexible substrate with an ITO conductive layer already formed on it;

[0063] S2. Spin-coat the PEDOT:PSS layer and TFB layer sequentially on the ITO conductive layer;

[0064] S3. Inkjet print the above ZnSe quantum dot ink onto the TFB layer to form a light-emitting layer;

[0065] S4. Spin-coat zinc magnesium oxide ink onto the light-emitting layer to form an electron transport layer;

[0066] S5. Evaporate an Al layer on the electron transport layer;

[0067] S6. Seal with encapsulating adhesive.

[0068] The quantum dot ink from Example 1 was inkjet printed using an OmniJet-500 GB inkjet printer (printhead model: Samba cartridge). The printing results are as follows: Figure 1-4 As shown, from Figure 1 The droplet size (4.1 pl) plot, and Figure 2 The state of droplets in inkjet printing and Figure 3 The 100-dot verification chart shows that the ink droplets are small and do not overlap, enabling high-quality printing; from Figure 4 The print waveform shows that the printing is smooth and suitable for inkjet printing at a relatively high speed.

[0069] Comparative Example 1

[0070] 1. Formulating quantum dot ink

[0071] Step S1: Dissolve 100 mg of blue-light ZnSe quantum dots in toluene to prepare a 15 mg / ml ZnSe quantum dot solution. The surface ligand of the ZnSe quantum dots is oleylamine.

[0072] Step S2: After vacuum drying to remove toluene from the ZnSe quantum dot solution, it is mixed with undecane and tetradecane solvents, wherein the mass percentage of tetradecane solvent is 15%, and the concentration of ZnSe quantum dots in the ink is 580 mg / mL. The mixture is stirred at room temperature for 30 min until the ZnSe quantum dots are completely dissolved. The solution is then filtered three times using a 0.22 μm filter and set aside for later use.

[0073] 2. Fabrication of electroluminescent devices

[0074] S1. Provide a flexible substrate with an ITO conductive layer already formed on it;

[0075] S2. Spin-coat the PEDOT:PSS layer and TFB layer sequentially on the ITO conductive layer;

[0076] S3. Inkjet print the above ZnSe quantum dot ink onto the TFB layer to form a light-emitting layer;

[0077] S4. Spin-coat zinc magnesium oxide ink onto the light-emitting layer to form an electron transport layer;

[0078] S5. Evaporate an Al layer on the electron transport layer;

[0079] S6. Seal with encapsulating adhesive.

[0080] The electroluminescent devices of Example 1 and Comparative Example 1 were subjected to power-on tests, and the test data are shown in Table 1 below.

[0081] Table 1

[0082]

[0083] It is evident that using modified quantum dots and adding Zn to the ink... + The additives significantly improved the current density, maximum current efficiency, brightness, and maximum external quantum efficiency of the prepared B-QLED devices, especially the maximum EQE, which increased from 1.2% to 5.4%.+ The presence of additives greatly improves the electrical performance of the device.

[0084] The film surface images of the electroluminescent devices of Example 1 and Comparative Example 1 were captured using a scanning electron microscope, as shown below. Figure 5-6 As shown, the electroluminescent device obtained in Example 1 of the present invention exhibits uniform light emission from its film surface without any dark spots; while the electroluminescent device in Comparative Example 1 shows uneven light emission from its film surface and the presence of dark spots. The modified quantum dots of the present invention are used to prepare the ink with a mixed polar solvent, resulting in high interfacial compatibility between the quantum dot emitting layer and the TFB layer, and thus uniform light emission from the film surface of the prepared electroluminescent device. The addition of Zn to the ink further enhances the effect. + The additives greatly improve the electrical performance of the device.

[0085] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A quantum dot ink, characterized in that, The ink comprises quantum dots, additives, and a mixed polar solvent. The quantum dots include a quantum dot body and organic segments attached to the surface of the quantum dot body. The organic segments are linked to functional groups soluble in the polar solvent. The mixed polar solvent contains a variety of polar solvents. The organic segments are derived from at least one of pentaerythritol tetra(3-mercaptopropionate), pentaerythritol tetra(3-mercaptobutyrate), and tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate. The functional groups soluble in the polar solvent include at least one of ester, ether, hydroxyl, amino, and amide groups. The additives include zinc halide compounds selected from at least one of zinc chloride, zinc bromide, and zinc iodide. The zinc halide accounts for 1%-10% of the mass of the quantum dot ink.

2. The quantum dot ink according to claim 1, characterized in that, The quantum dots are obtained by reacting the quantum dot bulk with an organic compound dispersed in a solvent, wherein the organic compound contains functional groups soluble in polar solvents.

3. The quantum dot ink according to claim 2, characterized in that, When the functional group soluble in polar solvents includes an ester group, the organic compound includes one of ethyl acetate, methyl formate, and glyceryl stearate; When the functional group soluble in polar solvents includes an ether group, the organic compound includes at least one of ethylene glycol butyl ether, dipropylene glycol methyl ether, propylene glycol ethyl ether, and propylene glycol butyl ether. When the functional group soluble in polar solvents includes a hydroxyl group, the organic compound includes one of methanol, ethanol, ethylene glycol, glycerol, n-butanol, cyclohexanehexyl alcohol, benzyl alcohol, phenol, cresol, aminophenol, nitrophenol, naphthol, and chlorophenol. When the functional group soluble in polar solvents includes an amine group, the organic compound includes one of dimethylamine, diethylamine, dipropylamine, dibutylamine, N-ethylmethylamine, and N-methyl-n-propylamine. When the functional group soluble in polar solvents includes an amide group, the organic compound includes at least one of formamide, acetamide, propionamide, butyramide, or isobutyramide.

4. The quantum dot ink according to claim 2, characterized in that, The solvent for dispersing the quantum dot bulk and the organic compound includes at least one of xylene, toluene, and trimethylbenzene.

5. The quantum dot ink according to claim 1, characterized in that, The mixed polar solvents include 3,5,5-trimethyl-1-hexanol, tripropylene glycol butyl ether, n-decyl alcohol, laurate methacrylate, and 4-tert-butylcyclohexyl acetate.

6. The quantum dot ink according to claim 5, characterized in that, In the quantum dot ink, the quantum dots account for 2%-3% of the total mass, the 3,5,5-trimethyl-1-hexanol accounts for 30%-32% of the total mass, the tripropylene glycol butyl ether accounts for 15%-17% of the total mass, the n-decyl alcohol accounts for 11%-13% of the total mass, the laurate methacrylate accounts for 5%-7% of the total mass, and the 4-tert-butylcyclohexyl acetate accounts for 31%-33% of the total mass.

7. The quantum dot ink according to claim 1, characterized in that, The quantum dots are selected from blue cadmium-free and lead-free quantum dots.

8. An electroluminescent device, characterized in that, It includes a light-emitting layer, which is prepared from the quantum dot ink according to any one of claims 1-7.

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