Reactive nanocrystals, nanocrystal photolithography solutions, electroluminescent nanocrystal layers and their preparation methods, and electroluminescent devices.

Abstract

This invention relates to the field of display technology, and discloses a reactive nanocrystal, a nanocrystal photolithography solution, an electroluminescent nanocrystal layer, a method for preparing the same, and an electroluminescent device. The reactive nanocrystal of this invention comprises a nanocrystal body and organic segments attached to the surface of the nanocrystal body. The organic segments include photocurable active functional groups and functional groups soluble in polar solvents. The photocurable active functional groups and the functional groups soluble in polar solvents can be located on different ligands of the same nanocrystal body, or they can be located on the same ligand of the nanocrystal body, representing different segments of that ligand. Under ultraviolet light irradiation and the action of a photoinitiator, the photocurable active functional groups undergo a polymerization reaction, and the resulting substance coats the nanocrystal body, thereby improving the surface stability of the nanocrystal and significantly enhancing the performance of the electroluminescent device prepared using this nanocrystal.

Description

Technical Field

[0001] This invention belongs to the field of display technology, and particularly relates to reactive nanocrystals, nanocrystal photolithography solutions, electroluminescent nanocrystal layers and their preparation methods, and electroluminescent devices. Background Technology

[0002] As a novel display technology, quantum dot light-emitting diodes (QLEDs) possess excellent characteristics such as narrow emission bandwidth, high luminous efficiency, tunable emission wavelength, high color gamut, and good photostability. More importantly, QLEDs are based on nanoscale quantum dots (QDs), and their performance is theoretically unaffected by pixel size, making them suitable for manufacturing high-resolution displays. The realization of QLED pixel patterns is mainly achieved through techniques such as inkjet printing (IJP), transfer printing, and photolithography.

[0003] Because quantum dot materials are inorganic nanoparticles, the industry previously generally believed that QLED mass production would be achieved through inkjet printing. However, due to the limitations of inkjet printing precision, its application is typically considered to be limited to large-size display products with resolutions of 300 PPI and below. Inkjet printing (IJP) not only faces the significant challenge of constructing pixels smaller than tens of micrometers, but also struggles to control the diffusion of solid nanoparticles in the ink within a confined space and the impact of three-phase contact line pinning during ink drying on film formation, resulting in non-uniform quantum dot films and poor device performance.

[0004] While transfer printing has shown unique potential in fabricating ultra-small pixels, the sagging and peeling of the flexible stamp inevitably affects the morphology and quality of the film. Especially at ultra-small scales, precise stamp alignment presents a significant challenge, making it difficult to manufacture high-resolution full-color devices.

[0005] Photolithography, as a simple, low-cost, and mature process, is widely used in the fabrication of display devices, enabling the construction of high-precision sub-pixels. In recent years, photolithography has been increasingly used in the fabrication of patterned quantum dot thin films. Mixing quantum dots with photoresist is a common patterning strategy. Due to its low cost, ease of mass production, and high-resolution patterns, photolithography is expected to become a highly promising quantum dot patterning technology.

[0006] Current methods for fabricating electroluminescent QLED devices using patterning techniques suffer from the problem of damaging quantum dots. For example, in patent application CN 114958072 A, a photoacid-generating agent is used during UV exposure of the quantum dot layer to catalyze the crosslinking reaction between the crosslinking agent and organic ligands in the quantum dot ink. However, during UV exposure, the photoacid-generating agent releases acidic protons, which are highly detrimental to quantum dots, impairing their luminous efficiency and resulting in a low maximum external quantum efficiency for the electroluminescent QLED device. Therefore, this method remains unsuitable for the mass production of electroluminescent QLED devices using patterning techniques.

[0007] Therefore, there is an urgent need to develop a new technique for patterning electro-QLED pixels to be suitable for mass production of electro-QLED devices. Summary of the Invention

[0008] In view of this, one object of the present invention is to provide a reactive nanocrystal comprising a nanocrystal body and organic segments attached to the surface of the nanocrystal body, wherein the organic segments contain photocurable active functional groups and functional groups soluble in polar solvents. The polar solvents here include at least one selected from 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, and propylene glycol butyl ether.

[0009] As a preferred embodiment of the aforementioned reactive nanocrystals, the photocurable active functional group includes substituted or unsubstituted propylene groups.

[0010] As a preferred embodiment of the above-mentioned reactive nanocrystals, the functional group soluble in polar solvents includes at least one of ester, ether, hydroxyl, amino, and amide groups.

[0011] As a preferred embodiment of the above-mentioned reactive nanocrystals, 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.

[0012] As a preferred embodiment of the above-mentioned reactive nanocrystals, the organic chain segments in the reactive nanocrystals have a weight percentage content of 5-80 wt%.

[0013] A second objective of this invention is to provide a nanocrystalline photolithography solution, comprising a mother liquor and the aforementioned reactive nanocrystals dispersed in the mother liquor, wherein the mother liquor comprises a polar solvent and a photoinitiator. Upon irradiation, the photocurable active functional groups on the surface of the reactive nanocrystals undergo a polymerization reaction.

[0014] As a preferred embodiment of the aforementioned nanocrystalline photolithography solution, based on the weight percentage of each component in the nanocrystalline photolithography solution, the content of the reactive nanocrystals is 1-20 wt%, the content of the polar solvent is 70-99 wt%, and the content of the photoinitiator is 0.01-0.2 wt%. The inventors have discovered that this content design allows for the acquisition of devices with excellent performance during patterned fabrication.

[0015] As a preferred embodiment of the aforementioned nanocrystalline photolithography solution, the polar solvent includes at least one of 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, and propylene glycol butyl ether.

[0016] The third objective of this invention is to provide an electroluminescent nanocrystalline layer, which is prepared by photolithography from the aforementioned nanocrystalline photolithography solution.

[0017] The fourth objective of this invention is to provide a method for preparing an electroluminescent nanocrystalline layer, comprising the following steps:

[0018] S1. Initial nanocrystals and organic compounds are dispersed in a first solvent and reacted to obtain the above-mentioned reactive nanocrystals. The organic compound contains photocurable active functional groups and functional groups soluble in polar solvents.

[0019] S2. The reactive nanocrystals and photoinitiator are dispersed in a polar solvent to form a photolithography solution;

[0020] S3. The photolithography solution is applied to the substrate, and a patterned nanocrystalline layer is obtained by photolithography.

[0021] Preferably, the reaction in S1 is carried out under an inert atmosphere, at a temperature of 25-150°C, and for a time of 0.5-48 hours.

[0022] As a preferred embodiment of the above-mentioned method for preparing electroluminescent nanocrystalline layers, the photolithography includes the process of sequentially exposing, developing, and drying the photolithography solution.

[0023] The fifth objective of this invention is to provide an electroluminescent device, comprising the above-described electroluminescent nanocrystalline layer or an electroluminescent nanocrystalline layer prepared by the above-described method.

[0024] Compared with the prior art, the present invention has at least the following advantages:

[0025] 1. The reactive nanocrystals of the present invention are formed by connecting organic segments to the surface of the nanocrystal body. The organic segments include photocurable active functional groups and functional groups soluble in polar solvents. The photocurable active functional groups and the functional groups soluble in polar solvents can be located on different ligands on the same nanocrystal or on the same ligand on the nanocrystal, and are different segments on the ligand. Under ultraviolet light irradiation and the action of a photoinitiator, the photocurable active functional groups undergo a polymerization reaction, and the resulting substance coats the nanocrystal body, thereby achieving the purpose of cross-linking the nanocrystal body.

[0026] 2. Due to the presence of photocurable active functional groups on the nanocrystal body, there is no need to use traditional resins, monomers, etc. when preparing nanocrystal photolithography solution. During patterning, spin coating, exposure and development can be performed directly, avoiding the resist removal step in traditional photolithography methods. The method is simple and reliable.

[0027] 3. The nanocrystal body also has functional groups that are soluble in polar solvents, which greatly improves its compatibility and solubility with polar solvents, and has a low cost advantage in mass production.

[0028] 4. The construction of multi-layer patterned nanocrystalline layers only requires repeated spin coating, exposure and development steps, making it easy to construct multi-layer patterned nanocrystalline devices with full red, green and blue colors.

[0029] 5. The electroluminescent nanocrystalline layer of the present invention enables the fabrication of full-color QLED devices. Compared with the sub-pixel size of tens of micrometers or larger currently constructed by inkjet printing, the present invention easily obtains devices with sub-micrometer-level high resolution and very high maximum external quantum efficiency, which are suitable for mass production. Attached Figure Description

[0030] 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.

[0031] Figure 1 This is a graph showing the relationship between the brightness and EQE of the red QLED device in Embodiment 1 of the present invention;

[0032] Figure 2 This is a graph showing the voltage versus EQE relationship of the red QLED device in Embodiment 1 of the present invention;

[0033] Figure 3 This is a schematic diagram showing the illumination of the red QLED device according to Embodiment 1 of the present invention;

[0034] Figure 4 This is a surface view of the electroluminescent nanocrystalline layer of the red QLED device in Embodiment 1 of the present invention;

[0035] Figure 5 This is a graph showing the relationship between the brightness and EQE of the green QLED device in Embodiment 2 of the present invention;

[0036] Figure 6 This is a graph showing the voltage versus EQE relationship of the green QLED device in Embodiment 2 of the present invention;

[0037] Figure 7 This is a schematic diagram showing the lighting of the green QLED device according to Embodiment 2 of the present invention;

[0038] Figure 8 This is a surface view of the electroluminescent nanocrystalline layer of the green QLED device in Embodiment 2 of the present invention;

[0039] Figure 9 This is a graph showing the relationship between brightness and EQE of the blue QLED device in Embodiment 3 of the present invention;

[0040] Figure 10 This is a graph showing the voltage versus EQE relationship of the blue QLED device in Embodiment 3 of the present invention;

[0041] Figure 11 This is a schematic diagram showing the blue QLED device lit up according to Embodiment 3 of the present invention;

[0042] Figure 12 This is a surface view of the electroluminescent nanocrystalline layer of the blue QLED device in Embodiment 3 of the present invention;

[0043] Figure 13 This is a graph showing the relationship between the brightness of the R-QLED and EQE in the QLED device of Embodiment 4 of the present invention;

[0044] Figure 14 This is a graph showing the relationship between the brightness of the G-QLED and EQE in the QLED device of Embodiment 4 of the present invention;

[0045] Figure 15 This is a schematic diagram of the QLED device being lit according to Embodiment 4 of the present invention;

[0046] Figure 16 This is the spectrum of the G-QLED in the QLED device of Embodiment 4 of the present invention;

[0047] Figure 17 This is the spectrum of the R-QLED in the QLED device of Embodiment 4 of the present invention;

[0048] Figure 18 This is a surface view of the electroluminescent nanocrystalline layer of the R-QLED in the QLED device of Embodiment 4 of the present invention;

[0049] Figure 19 This is a surface view of the electroluminescent nanocrystalline layer of the G-QLED in the QLED device of Embodiment 4 of the present invention;

[0050] Figure 20 This is a graph showing the relationship between the brightness of the R-QLED and EQE in the QLED device of Embodiment 5 of the present invention;

[0051] Figure 21 This is a graph showing the relationship between the brightness and EQE of the G-QLED in the QLED device of Embodiment 5 of the present invention;

[0052] Figure 22 This is a graph showing the relationship between the brightness and EQE of the B-QLED in the QLED device of Embodiment 5 of the present invention;

[0053] Figure 23 This is a schematic diagram of the QLED device being lit according to Embodiment 5 of the present invention;

[0054] Figure 24 This is the spectrum of the R-QLED in the QLED device of Embodiment 5 of the present invention;

[0055] Figure 25 This is the spectrum of the G-QLED in the QLED device of Embodiment 5 of the present invention;

[0056] Figure 26 This is the spectrum of the B-QLED in the QLED device of Embodiment 5 of the present invention;

[0057] Figure 27 This is a surface view of the electroluminescent nanocrystalline layer of the R-QLED in the QLED device of Embodiment 5 of the present invention;

[0058] Figure 28 This is a surface view of the electroluminescent nanocrystalline layer of the G-QLED in the QLED device of Embodiment 5 of the present invention;

[0059] Figure 29 This is a surface view of the electroluminescent nanocrystalline layer of the B-QLED in the QLED device of Embodiment 5 of the present invention;

[0060] Figure 30 This is a surface view of the electroluminescent nanocrystalline layer of the R-QLED in Comparative Example 1 of this invention;

[0061] Figure 31 This is a surface view of the electroluminescent nanocrystalline layer of the G-QLED in Comparative Example 2 of this invention;

[0062] Figure 32 This is a surface view of the electroluminescent nanocrystalline layer of the B-QLED in Comparative Example 3 of the present invention. Detailed Implementation

[0063] 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.

[0064] 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.

[0065] 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”.

[0066] 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.

[0067] 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%.

[0068] Because the surface of quantum dots is typically composed of ligands such as oleic acid or oleylamine, its surface properties limit the solubility of quantum dots in traditional photoresists, resulting in poor compatibility. This leads to the need for large amounts of photoresist to dissolve sufficient quantum dots during the patterning fabrication of electroluminescent QLED devices. Furthermore, large amounts of organic solvents are required during the patterning process of the quantum dot layer to dissolve the photoresist for coating and development after exposure. The large amounts of photoresist and organic solvents increase costs and cause environmental problems. Therefore, in a preferred embodiment of the present invention, a reactive nanocrystal is provided, comprising a nanocrystal body and organic segments connected to the surface of the nanocrystal body. These organic segments contain photocurable active functional groups and functional groups soluble in polar solvents. It is understood that the photocurable active functional groups and the functional groups soluble in polar solvents can be located on different ligands of the same nanocrystal body, or they can be located on the same ligand as different segments of that ligand.

[0069] Specifically, the photocurable active functional groups include substituted or unsubstituted propylene groups, such as acrylic acid groups located at the ends of organic chain segments. These photocurable active functional groups can be derived from acrylic acid-acrylate copolymers. That is, propylene copolymers are used as crosslinking agents to form network molecules in the form of carbon-carbon double bonds, resulting in strong covalent bonding and a stable crosslinked network structure. Under ultraviolet light irradiation and the action of a photoinitiator, the double bonds in these photocurable active functional groups will undergo a polymerization reaction, and the resulting substance will coat the nanocrystal body, thereby improving the surface stability of the nanocrystals. The resolution and maximum external quantum efficiency of nanocrystalline electroluminescent devices prepared from these nanocrystals will be significantly improved.

[0070] The photoinitiators here include at least one of 2,4,6-trimethylbenzoylphenylphosphonate, 2-dimethylamino-2-benzyl-1-[4-(4-morpholino)phenyl]-1-butanone, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone, methyl benzoylcarbamate, 2,4-dihydroxybenzophenone, diphenyl-(2,4,6-trimethylbenzoyl)phosphine, and 5-nitroacenaphthene.

[0071] Specifically, the functional groups of the present invention that are soluble in polar solvents include at least one of ester, ether, hydroxyl, amino, and amide groups. These groups facilitate the dissolution of organic segments attached to the surface of the nanocrystals in polar solvents. The polar solvents include at least one of 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, and propylene glycol butyl ether, which are highly polar organic solvents. The nanocrystals inherently possess functional groups soluble in polar solvents, significantly improving their solubility in the aforementioned polar solvents.

[0072] Specifically, the organic chain segments on the surface of the nanocrystal body of the present invention include at least one of thiol, carboxyl, amine, and amide groups to facilitate coordination and connection with the surface of the nanocrystal body.

[0073] In one specific embodiment, the organic chain segments in the reactive nanocrystals of the present invention comprise 5-80 wt%, preferably 10-30 wt%. The electroluminescent nanocrystal layer prepared using these reactive nanocrystals exhibits excellent stability.

[0074] Preferably, 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.

[0075] Since the nanocrystals of the present invention have photocurable active functional groups and functional groups that can be dissolved in polar solvents, when patterning QLED devices, it is only necessary to mix the nanocrystals, polar solvents and photoinitiators. There is no need to add monomers, resins, etc. Spin coating, exposure and development can be performed directly, eliminating the resist removal step in the traditional photolithography method. The method is simple and reliable.

[0076] This invention also provides a nanocrystalline photolithography solution, comprising a mother liquor and the aforementioned reactive nanocrystals dispersed in the mother liquor, wherein the mother liquor comprises a polar solvent and a photoinitiator. Upon illumination, the photocurable active functional groups on the surface of the reactive nanocrystals undergo a polymerization reaction. The polymerization reaction of this invention can occur between photocurable active functional groups on the same nanocrystal surface, or between photocurable active functional groups on different nanocrystal surfaces, or both of the aforementioned polymerization reactions can occur simultaneously. This results in the nanocrystal body surface being coated with highly cross-linked polymer molecules, thereby improving the stability of the reactive nanocrystal surface. Under electrical excitation, the reactive nanocrystals exhibit excellent optical properties.

[0077] In one specific embodiment of the present invention, the formulation of the nanocrystalline photolithography solution, based on the weight percentage of each component in the nanocrystalline photolithography solution, includes: 1-20 wt% of reactive nanocrystals, 70-99 wt% of polar solvent, and 0.01-0.2 wt% of photoinitiator. The reactive nanocrystals exhibit good dispersibility in the polar solvent (the polar solvent includes at least one of 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, and propylene glycol butyl ether). Under ultraviolet light irradiation, the organic segments on the surface of the reactive nanocrystals undergo a polymerization reaction to form a nanocrystalline photolithography solution that is easy to spin-coat.

[0078] The present invention also provides an electroluminescent nanocrystalline layer, which is obtained by photolithography from the above-mentioned nanocrystalline photolithography solution. Under ultraviolet light irradiation, the organic segments on the surface of the reactive nanocrystals in the nanocrystalline photolithography solution undergo a polymerization reaction, forming a thin polymer layer on the surface of the nanocrystal body, protecting the surface of the nanocrystal body. Then, the polar solvent is evaporated to obtain an electroluminescent nanocrystalline layer with excellent photoelectric properties.

[0079] The present invention also provides a method for preparing the above-mentioned electroluminescent nanocrystalline layer, comprising the steps of:

[0080] S0, Preparation of initial nanocrystals.

[0081] In this invention, the initial nanocrystals comprise at least one of group II-VI compounds, group III-V compounds, and perovskite nanocrystals. For example, group II-VI compounds may include: CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgS Te, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, HgZnT eS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe or combinations thereof. Group III-V compounds may include: 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 include organic perovskite nanocrystals and / or inorganic perovskite nanocrystals, which may be commercially available products.

[0082] The initial nanocrystals were prepared using existing solution-based preparation techniques, followed by purification, and will not be elaborated here.

[0083] S1. Initial nanocrystals and organic compounds are dispersed in a first solvent and reacted to obtain surface-modified nanocrystals. The organic compound contains photocurable active functional groups and functional groups soluble in polar solvents.

[0084] The reaction temperature between the initial nanocrystals and the organic compound in this invention is 20-120°C, thereby binding the organic compound to the surface of the initial nanocrystals to obtain reactive nanocrystals.

[0085] S2. Disperse reactive nanocrystals and photoinitiators in a polar solvent to form a photolithography solution.

[0086] S3. The photolithography solution is applied to the substrate, and a patterned nanocrystalline layer is obtained by photolithography.

[0087] Preferably, the reaction in step S1 is carried out under an inert atmosphere at a temperature of 25-150°C for 0.5-48 hours. The first solvent includes at least one of xylene, toluene, and trimethylbenzene. Such solvents can better dissolve the initial nanocrystals and organic compounds, and promote efficient reaction.

[0088] In step S1, the initial nanocrystals and organic compounds are fed in a ratio of 100:(5-200) to facilitate subsequent photolithography processes and obtain electroluminescent devices with superior optical performance.

[0089] Preferably, the mixing temperature in step S2 is 20-120°C, and the mixing time is 1-20 hours.

[0090] In one specific embodiment of the present invention, photolithography includes the process of sequentially exposing, developing, and drying the photolithography solution. Compared with conventional photolithography processes in the prior art, to avoid deactivation of reactive nanocrystals, the photolithography process of the present invention does not include a pre-baking step for the nanocrystal photolithography solution. Exposure refers to irradiating the nanocrystal photolithography solution under ultraviolet light for 10-40 seconds under the protection of a photomask. Development involves rinsing the exposed nanocrystal photolithography solution with a polar solvent for 30-500 seconds. Drying involves baking at 70-150°C for 5-50 minutes.

[0091] It is understood that the nanocrystal body of the reactive nanocrystal of the present invention is derived from the initial nanocrystal, that is, the nanocrystal body of the reactive nanocrystal of the present invention is the initial nanocrystal.

[0092] This invention also provides an electroluminescent device, comprising the above-described electroluminescent nanocrystalline layer, or an electroluminescent nanocrystalline layer prepared by the above-described method. This electroluminescent device exhibits stable light emission, high brightness and resolution, and can achieve an external quantum efficiency of 1-30%.

[0093] This invention employs a nanocrystalline direct photolithography patterning process, which breaks through the resolution limitations of traditional vapor deposition and inkjet printing processes. Theoretically, its resolution depends on the precision of the exposure machine and the photomask. In principle, it can even achieve submicron-level pattern linewidths and pixel densities of over 10,000 PPI.

[0094] Nanocrystalline direct lithography enables highly flexible combinations of size and pixel density across the entire size range, highly flexible pixel arrangement design, higher aperture ratio and device lifespan, simpler process technology, and more flexible and efficient product development. This greatly promotes the commercialization of QLED technology in the small and medium-sized panel market and the micro-display market, helping to achieve full-size coverage of QLED technology in the display field and bringing customers the ultimate visual experience.

[0095] Some exemplary embodiments of the present invention are described in more detail below; however, the exemplary embodiments of the present invention are not limited thereto.

[0096] Example 1

[0097] Synthesis of S0 and red-light CdZnSe / ZnCdS / ZnS nanocrystals

[0098] Preparation of anionic precursors: Take 10 mmol of selenium powder and mix it thoroughly with tri-n-octylphosphine to obtain the selenium source precursor (Se-TOP, 2M); take 10 mmol of sulfur powder and mix it thoroughly with tri-n-octylphosphine to obtain the sulfur source precursor (S-TOP, 2M).

[0099] Preparation of cationic precursors: Take 10 mmol of anhydrous zinc acetate, add 10 ml of oleic acid and 10 ml of octadecene, vacuum at 120°C until no bubbles are present, purge with N2, and keep warm at 100°C until ready for use to obtain zinc oleate precursor (0.5 M); Take 10 mmol of cadmium oxide, add 12 ml of oleic acid and 38 ml of octadecene, vacuum at 120°C until no bubbles are present, purge with N2, heat to 240°C, keep warm for 60 minutes, and then cool to obtain cadmium oleate precursor (0.2 M).

[0100] Synthesis of CdZnSe / ZnCdS / ZnS nanocrystals: 6 mmol of zinc oleate and 6 mmol of cadmium oleate were mixed, and after three evacuations, the mixture was heated to 320°C with N2. 6 ml of Se-TOP was rapidly injected, and the reaction was allowed to proceed for 60 minutes. The mixture was then cooled to 280°C, and 12 mmol of zinc oleate was added. 3 ml of S-TOP solution (2M, a sulfur precursor formed by dissolving sulfur powder in trioctylphosphide) and 6 mmol of cadmium oleate were added dropwise, and the reaction was allowed to proceed for 40 minutes. Finally, 20 mmol of zinc oleate was added, and 6 ml of dodecanethiol was added dropwise, and the reaction was allowed to proceed for 60 minutes. The mixture was cooled to room temperature, and the product was precipitated and purified using n-heptane and ethanol to finally obtain CdZnSe / ZnCdS / ZnS nanocrystals.

[0101] S1. Preparation of reactive nanocrystals:

[0102] 100 mg of red-light CdZnSe / ZnCdS / ZnS nanocrystals and 5 mg of pentaerythritol tetra(3-mercaptopropionate) were added to 1 ml of xylene and reacted at 80 °C under nitrogen for 30 minutes. Then, 5 mg of acrylate-acrylate copolymer was added and reacted at 60 °C for 60 minutes. Then, 5 mg of succinate mono[2-[(2-methyl-acryloyl)oxy]ethyl] ester was added and reacted at 120 °C for 60 minutes to obtain a reactive nanocrystal solution. After vacuum drying to remove xylene from the reactive nanocrystal solution, reactive nanocrystals were obtained.

[0103] S2. Preparation of photolithography solution:

[0104] The above-mentioned reactive nanocrystals were added to 5 ml of PGMEA solution, stirred evenly, and then 3 mg of TPO was added. The mixture was stirred evenly at 60 °C in the dark to obtain the initial photolithography solution.

[0105] Centrifuge the initial photolithography solution for 10 minutes, take the supernatant, and filter it three times using a 0.22μm filter to obtain the photolithography solution.

[0106] S3. Fabrication of QLED devices:

[0107] 1) A poly(ethylene dioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) layer with a thickness of 45 nm and a poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer with a thickness of 40 nm were sequentially prepared on indium tin oxide glass (first electrode).

[0108] 2) Spin-coat the above photoresist onto the TFB layer, expose (under the protection of a mask, irradiate under ultraviolet light for 50s), develop (immerse in developer and rinse with PGMEA), and bake at 120°C for 20 minutes to obtain a nanocrystalline layer with a thickness of 25nm.

[0109] 3) A 65 nm thick zinc oxide (ZnO) layer was fabricated on the nanocrystalline layer; an Al cathode layer was deposited on the ZnO layer and then encapsulated to form a red QLED device (R-QLED). The optical parameters of this red QLED device are shown in the table below:

[0110] type Start-up voltage (V) EQE max(%) Brightness (nits) / 4V Emission peak wavelength, nm / full width at half maximum (FWHM), nm R-QLED 2.0 27.4 41800 632 / 24

[0111] As can be seen, the red QLED device starts normally at a voltage of 2.0V, with a maximum external quantum efficiency of 27.4%, and a brightness of 41,800 nits at a voltage of 4V.

[0112] like Figure 1 The relationship between the brightness and EQE of the red QLED device shown is evident. It can be seen that the external quantum efficiency changes gradually as the brightness increases.

[0113] like Figure 2 The relationship between voltage and EQE of the red QLED device is shown. It can be seen that the external quantum efficiency changes gradually with the increase of voltage.

[0114] like Figure 3 The red QLED device shown in the image is illuminated, and it is evident that the light output is uniform.

[0115] like Figure 4 The electroluminescent nanocrystalline film of the red QLED device shown here has excellent flatness.

[0116] Example 2

[0117] Synthesis of S0 and green CdZnSeS / ZnS nanocrystals

[0118] Preparation of anionic precursors: Take 10 mmol of selenium powder and mix it thoroughly with tri-n-octylphosphine to obtain the selenium source precursor (Se-TOP, 2M); take 10 mmol of sulfur powder and mix it thoroughly with tri-n-octylphosphine to obtain the sulfur source precursor (S-TOP, 2M).

[0119] Preparation of cationic precursors: Take 10 mmol of anhydrous zinc acetate, add 10 ml of oleic acid and 10 ml of octadecene, vacuum at 120°C until no bubbles are present, purge with N2, and maintain at 100°C until ready for use. This yields the zinc oleate precursor (0.5 M). Take 10 mmol of cadmium oxide, add 12 ml of oleic acid and 38 ml of octadecene, vacuum at 120°C until no bubbles are present, purge with N2, heat to 240°C, maintain for 60 minutes, and then cool to obtain the cadmium oleate precursor (0.2 M).

[0120] Synthesis of green-light CdZnSeS / ZnS nanocrystals: 20 mmol of zinc oleate and 1 mmol of cadmium oleate were mixed, and after three evacuations, the mixture was heated to 320°C with N2. 5 ml of Se-TOP and 5 ml of S-TOP mixture were quickly injected, and the reaction was carried out for 30 minutes. The temperature was then lowered to 240°C, 10 mmol of zinc oleate was added, and 3 ml of dodecanethiol was added dropwise. The reaction was carried out for 60 minutes, and the temperature was lowered to room temperature. The product was precipitated and purified using n-heptane and ethanol to finally obtain CdZnSeS / ZnS nanocrystals.

[0121] S1. Preparation of reactive nanocrystals:

[0122] 100 mg of green-light CdZnSeS / ZnS nanocrystals and 10 mg of pentaerythritol tetra(3-mercaptopropionate) were added to 1 ml of xylene and reacted at 80 °C under nitrogen for 60 minutes. Then, 8 mg of acrylate-acrylate copolymer was added and reacted at 60 °C for 60 minutes. Then, 5 mg of succinate mono[2-[(2-methyl-acryloyl)oxy]ethyl] ester was added and reacted at 120 °C for 60 minutes to obtain a reactive nanocrystal solution. After vacuum drying to remove xylene from the reactive nanocrystal solution, reactive nanocrystals were obtained.

[0123] S2. Preparation of photolithography solution:

[0124] The above-mentioned reactive nanocrystals were added to 5 ml of PGMEA solution, stirred evenly, and then 3 mg of TPO was added. The mixture was stirred evenly at 60 °C in the dark to obtain the initial photolithography solution.

[0125] After centrifuging the initial photolithography solution for 10 minutes, take the supernatant and filter it three times using a 0.22μm filter to obtain the photolithography solution.

[0126] S3. Fabrication of QLED devices:

[0127] 1) A poly(ethylene dioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) layer with a thickness of 45 nm and a poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer with a thickness of 40 nm were sequentially prepared on indium tin oxide glass (first electrode).

[0128] 2) Spin-coat the above photoresist onto the TFB layer, expose (under the protection of a mask, irradiate under ultraviolet light for 50s), develop (immerse in developer and rinse with PGMEA), and bake at 120°C for 20 minutes to obtain a nanocrystalline layer with a thickness of 25nm.

[0129] 3) A 65 nm thick zinc oxide (ZnO) layer was fabricated on the nanocrystalline layer; an Al cathode layer was deposited on the ZnO layer and then encapsulated to form a green QLED device (G-QLED). The optical parameters of this green QLED device are shown in the table below:

[0130] type Start-up voltage (V) EQE max(%) Brightness (nits) / 4V Emission peak wavelength, nm / full width at half maximum (FWHM), nm G-QLED 2.4 9.6 96980 536 / 24

[0131] As can be seen, the green QLED device starts normally at 2.4V, with a maximum external quantum efficiency of 9.6%, and a brightness of 96,980 nits at 4V.

[0132] like Figure 5 The relationship between the brightness and EQE of the green QLED device shown is evident. It can be seen that the external quantum efficiency changes gradually with the increase of brightness.

[0133] like Figure 6 The relationship between voltage and EQE of the green QLED device is shown. It can be seen that the external quantum efficiency changes gradually with the increase of voltage.

[0134] like Figure 7 The green QLED device shown in the image is illuminated, and it is evident that the light output is uniform.

[0135] like Figure 8 The electroluminescent nanocrystalline film of the green QLED device shown here has excellent flatness.

[0136] Example 3

[0137] Synthesis of S0 and blue CdZnSeS / ZnS nanocrystals

[0138] Preparation of anionic precursors: Take 10 mmol of selenium powder and mix it thoroughly with tri-n-octylphosphine to obtain the selenium source precursor (Se-TOP, 2M); take 10 mmol of sulfur powder and mix it thoroughly with tri-n-octylphosphine to obtain the sulfur source precursor (S-TOP, 2M).

[0139] Preparation of cationic precursors: Take 10 mmol of anhydrous zinc acetate, add 10 ml of oleic acid and 10 ml of octadecene, vacuum at 120°C until no bubbles are present, purge with N2, and keep warm at 100°C until ready for use to obtain zinc oleate precursor (0.5 M); Take 10 mmol of cadmium oxide, add 12 ml of oleic acid and 38 ml of octadecene, vacuum at 120°C until no bubbles are present, purge with N2, heat to 240°C, keep warm for 60 minutes, and then cool to obtain cadmium oleate precursor (0.2 M).

[0140] Synthesis of blue-light CdZnSeS / ZnS nanocrystals: 20 mmol of zinc oleate and 1 mmol of cadmium oleate were mixed, and after three gas exchanges, the mixture was heated to 320°C with N2. 1 ml of Se-TOP and 9 ml of S-TOP mixture were quickly injected, and the reaction was carried out for 30 minutes. The temperature was then lowered to 240°C, 10 mmol of zinc oleate was added, and 3 ml of dodecanethiol was added dropwise. The reaction was carried out for 60 minutes, and the temperature was lowered to room temperature. The product was precipitated and purified using n-heptane and ethanol to finally obtain CdZnSeS / ZnS nanocrystals.

[0141] S1. Preparation of reactive nanocrystals:

[0142] 100 mg of blue-light CdZnSeS / ZnS nanocrystals and 10 mg of pentaerythritol tetra(3-mercaptopropionate) were added to 1 ml of xylene and reacted at 80 °C under nitrogen for 60 minutes. Then, 6 mg of acrylate-acrylate copolymer was added and reacted at 60 °C for 60 minutes. Then, 4 mg of succinate mono[2-[(2-methyl-acryloyl)oxy]ethyl] ester was added and reacted at 120 °C for 60 minutes to obtain a reactive nanocrystal solution. After vacuum drying to remove xylene from the reactive nanocrystal solution, reactive nanocrystals were obtained.

[0143] S2. Preparation of photoresist solution:

[0144] The above-mentioned reactive nanocrystals were added to 5 ml of PGMEA, stirred evenly, and then 2 mg of TPO was added. The mixture was stirred evenly at 60°C in the dark to obtain the initial photolithography solution.

[0145] After centrifuging the initial photoresist at 10,000 rpm for 10 minutes, the supernatant was collected and filtered three times using a 0.22 μm filter to obtain the photoresist.

[0146] S3. Fabrication of QLED devices:

[0147] 1) A poly(ethylene dioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) layer with a thickness of 45 nm and a poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer with a thickness of 40 nm were sequentially prepared on indium tin oxide glass (first electrode).

[0148] 2) Spin-coat the above photoresist onto the TFB layer, expose (under the protection of a mask, irradiate under ultraviolet light for 50s), develop (immerse in developer and rinse with PGMEA), and bake at 120°C for 20 minutes to obtain a nanocrystalline layer with a thickness of 25nm.

[0149] 3) A zinc oxide (ZnO) layer with a thickness of 65 nm was prepared on the nanocrystalline layer; an Al cathode layer was deposited on the ZnO layer and then encapsulated to form a blue QLED device. The optical parameters of this blue QLED device (B-QLED) are shown in the table below:

[0150] type Start-up voltage (V) EQE max(%) Brightness (nits) / 4V Emission peak wavelength, nm / full width at half maximum (FWHM), nm B-QLED 2.6 1.28 6256 476 / 26

[0151] As can be seen, the blue QLED device starts normally at 2.6V, with a maximum external quantum efficiency of 1.28%, and a brightness of 6256 nits at 4V.

[0152] like Figure 9The relationship between the brightness and EQE of the blue QLED device shown is evident. It can be seen that the external quantum efficiency changes gradually as the brightness increases.

[0153] like Figure 10 The relationship between voltage and EQE of the blue QLED device is shown. It can be seen that the external quantum efficiency changes gradually with the increase of voltage.

[0154] like Figure 11 The blue QLED device shown in the image is illuminated, and it is evident that the light output is uniform.

[0155] like Figure 12 The electroluminescent nanocrystalline film of the blue QLED device shown here has excellent flatness.

[0156] Example 4

[0157] The preparation of the red nanocrystals and photolithography solution in this embodiment is the same as in Example 1, and the preparation of the green nanocrystals and photolithography solution is the same as in Example 2. The difference lies in step S3 as follows:

[0158] 1) A poly(ethylene dioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) layer with a thickness of 45 nm and a poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer with a thickness of 40 nm were sequentially prepared on indium tin oxide glass (first electrode).

[0159] 2) Spin-coat the photoresist of Example 1 onto the TFB layer, expose it with UV (energy 400mJ / cm2), develop it (rinse with PGMEA), and bake it at 120°C for 20 minutes to obtain a red nanocrystalline layer with a thickness of 25nm.

[0160] 3) Spin-coat the photoresist of Example 2 onto the TFB layer, expose it with UV (energy 300mJ / cm2), develop it (rinse with PGMEA), and bake it at 120°C for 20 minutes to obtain a green nanocrystalline layer with a thickness of 25nm.

[0161] 4) Zinc oxide (ZnO) layers with a thickness of 65 nm were fabricated on the red and green nanocrystalline layers, respectively; an Al cathode layer was deposited on the ZnO layers and then encapsulated to form a QLED device displaying red and green light on the substrate. The optical parameters of this QLED device are shown in the table below:

[0162] type Start-up voltage (V) EQE max(%) Brightness (nits) Emission peak wavelength, nm / full width at half maximum (FWHM), nm R-QLED 2.2 12.8 / 2.8V 125700 / 7V 632 / 28 G-QLED 2.4 8.2 / 3.4V 133300 / 7V 536 / 25

[0163] like Figure 13 The diagram shows the relationship between brightness and EQE for a red QLED device (R-QLED). It can be seen that as brightness increases, the EQE of the R-QLED first decreases, then increases, and remains stable. Figure 14 The relationship between brightness and EQE of the green QLED device (G-QLED) is shown. It can be seen that as the brightness increases, the EQE of G-QLED decreases slightly and then remains stable.

[0164] like Figure 15 The QLED device shown in the image is illuminated, and it is evident that the light output is uniform.

[0165] like Figure 16 , 17 The spectra of the G-QLED and R-QLED under different voltages are shown respectively. It can be seen that the spectra are relatively pure and there is no light interference from other bands.

[0166] like Figure 18 , 19 The electroluminescent nanocrystalline layer film surface conditions of the R-QLED and G-QLED in the QLED device are shown respectively. It can be seen that the film surface has very good flatness.

[0167] Example 5

[0168] The preparation of red nanocrystals and photolithography solution in this embodiment is the same as in Example 1; the preparation of green nanocrystals and photolithography solution is the same as in Example 2; and the preparation of blue nanocrystals and photolithography solution is the same as in Example 3. The difference lies in step S3 as follows:

[0169] 1) A poly(ethylene dioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) layer with a thickness of 45 nm and a poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer with a thickness of 40 nm were sequentially prepared on indium tin oxide glass (first electrode).

[0170] 2) Spin-coat the photoresist of Example 1 onto the TFB layer, expose it with UV (energy 400mJ / cm2), develop it (rinse with PGMEA), and bake it at 120°C for 20 minutes to obtain a red nanocrystalline layer with a thickness of 25nm.

[0171] 3) Spin-coat the photoresist of Example 2 onto the TFB layer, expose it with UV (energy 300mJ / cm2), develop it (rinse with PGMEA), and bake it at 120°C for 20 minutes to obtain a green nanocrystalline layer with a thickness of 25nm.

[0172] 4) Spin-coat the photolithography solution of Example 3 onto the TFB layer, expose it with UV (energy 300mJ / cm2), develop it (rinse with PGMEA), and bake it at 120°C for 20 minutes to obtain a blue nanocrystalline layer with a thickness of 25nm.

[0173] 5) Zinc oxide (ZnO) layers with a thickness of 65 nm were fabricated on the red, green, and blue nanocrystalline layers, respectively; an Al cathode layer was deposited on the ZnO layers and then encapsulated to form QLED devices displaying red, green, and blue light on the substrate. The optical parameters of the QLED devices are shown in the table below:

[0174] type Start-up voltage (V) EQE max(%) Brightness (nits) / 4V Emission peak wavelength, nm / full width at half maximum (FWHM), nm R-QLED 2.2 12.8 / 2.8V 14250 632 / 28 G-QLED 2.2 10.4 / 3.0V 29740 536 / 24 B-QLED 2.5 1.62 / 3.9V 2061 472 / 22

[0175] like Figure 20 The diagram shows the relationship between brightness and EQE for red QLED devices (R-QLED). It can be seen that the EQE of R-QLEDs changes steadily as brightness increases. Figure 21 The diagram shows the relationship between brightness and EQE for green QLED devices (G-QLED). It can be seen that as brightness increases, the EQE of G-QLEDs maintains a stable trend. Figure 22 The relationship between brightness and EQE of green QLED devices (B-QLED) is shown. It can be seen that as the brightness increases, the EQE of B-QLED rises steadily and then decreases slightly.

[0176] like Figure 23 The QLED device shown in the image is illuminated, and it is evident that the light output is uniform.

[0177] like Figure 24 , 25 Figures 26 show the spectra of the R-QLED, G-QLED, and B-QLED under different voltage illumination conditions. As can be seen, the spectra are relatively pure and free from light interference from other wavelengths.

[0178] like Figure 27 , 28 The electroluminescent nanocrystalline layer film conditions of R-QLED, G-QLED, and B-QLED in the QLED device are shown in Figures 29 and 29 respectively. It can be seen that the film surface has very good flatness.

[0179] Comparative Example 1

[0180] A 45 nm thick poly(ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) layer, a 40 nm thick poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer, a 25 nm thick R-QD layer (conventionally inkjet printed), and a 65 nm thick ZnO layer were sequentially spin-coated onto an indium tin oxide glass (first electrode). An Al cathode layer was then deposited on the ZnO layer, and the layers were encapsulated to form an R-QLED. The electroluminescent nanocrystalline film surface of this R-QLED is shown below. Figure 30The film surface is rough and uneven.

[0181] Comparative Example 2

[0182] A 45 nm thick poly(ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) layer, a 40 nm thick poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer, a 25 nm thick G-QD layer (conventionally inkjet printed), and a 65 nm thick ZnO layer were sequentially spin-coated onto an indium tin oxide glass (first electrode). An Al cathode layer was then deposited on the ZnO layer, and the device was encapsulated to form a green QLED device. The electroluminescent nanocrystalline layer surface of this G-QLED is shown below. Figure 31 The film surface is rough and uneven.

[0183] Comparative Example 3

[0184] A 45 nm thick poly(ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) layer, a 40 nm thick poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer, a 25 nm thick B-QD layer (conventionally inkjet printed), and a 65 nm thick ZnO layer were sequentially spin-coated onto an indium tin oxide glass (first electrode). An Al cathode layer was then deposited on the ZnO layer, and the device was encapsulated to form a blue QLED device. The electroluminescent nanocrystalline layer surface of this B-QLED is shown below. Figure 32 The film surface is rough and uneven.

[0185] The optical parameters of the devices in Comparative Examples 1-3 are summarized in the following table:

[0186] type Start-up voltage EQEmax (%) Brightness (nits) / 4V Emission peak wavelength, nm / full width at half maximum (FWHM), nm Comparative Example 1 1.8 27.3 98720 628 / 25 Comparative Example 2 2.4 6.3 1761 536 / 23 Comparative Example 3 2.8 7.3 688.9 476 / 24

[0187] As can be seen, compared with the QLED devices formed by nanocrystals in Comparative Examples 1-3, the QLED devices formed by reactive nanocrystals in Examples 1-5 of this application have higher external quantum efficiency (EQE) and can maintain a higher level for a longer period of time, and the electroluminescent nanocrystal layer film surface has better smoothness. The reactive nanocrystals prepared by the technical solution of this application have good electrical properties, and the light-emitting devices made from them have excellent photoelectric performance and high resolution, thereby facilitating the commercial application of optical elements containing reactive nanocrystals.

[0188] 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 reactive nanocrystal, characterized in that, The invention comprises a nanocrystal body and organic segments attached to the surface of the nanocrystal body. The organic segments contain photocurable active functional groups and functional groups soluble in polar solvents. The raw material composition of the organic segments is pentaerythritol tetra(3-mercaptopropionate), acrylate-acrylate copolymer, and succinate mono[2-[(2-methyl-acryloyl)oxy]ethyl] ester.

2. The reactive nanocrystals according to claim 1, characterized in that, In the reactive nanocrystals, the organic chain segments have a weight percentage of 5-80 wt%.

3. A nanocrystalline photolithography solution, characterized in that, The mixture includes a mother liquor and reactive nanocrystals as described in any one of claims 1-2 dispersed in the mother liquor, wherein the mother liquor includes a polar solvent and a photoinitiator.

4. The nanocrystalline photolithography solution according to claim 3, characterized in that, Based on the weight percentage of each component in the nanocrystalline photolithography solution, the content of the reactive nanocrystals is 1-20 wt%, the content of the polar solvent is 70-99 wt%, and the content of the photoinitiator is 0.01-0.2 wt%.

5. The nanocrystalline photolithography solution according to claim 4, characterized in that, The polar solvent includes at least one of 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, and propylene glycol butyl ether.

6. An electroluminescent nanocrystalline layer, characterized in that, It is prepared by photolithography using the nanocrystalline photolithography solution described in any one of claims 3-5.

7. A method for preparing an electroluminescent nanocrystalline layer, characterized in that, Including the following steps: S1. Initial nanocrystals and organic compounds are dispersed in a first solvent and reacted to obtain reactive nanocrystals as described in any one of claims 1-2, wherein the organic compound contains photocurable active functional groups and functional groups soluble in polar solvents. S2. The reactive nanocrystals and photoinitiator are dispersed in a polar solvent to form a photolithography solution; S3. The photolithography solution is applied to the substrate, and a patterned nanocrystalline layer is obtained by photolithography.

8. The method for preparing the electroluminescent nanocrystalline layer according to claim 7, characterized in that, The photolithography process includes sequentially exposing, developing, and drying the photolithography solution.

9. An electroluminescent device, characterized in that, Includes the electroluminescent nanocrystalline layer as described in claim 6, or the electroluminescent nanocrystalline layer prepared by the method described in any one of claims 7-8.

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