Nanocrystal having reaction activity, nanocrystalline photoetching liquid, electroluminescent nanocrystalline layer and preparation method therefor, and electroluminescent device

Abstract

The present invention relates to the technical field of display. Disclosed are a nanocrystal having reaction activity, a nanocrystalline photoetching liquid, an electroluminescent nanocrystalline layer and a preparation method therefor, and an electroluminescent device. The nanocrystal having reaction activity of the present invention comprises a nanocrystal body and an organic substance chain segment connected to the surface of the nanocrystal body, wherein the organic substance chain segment comprises a photocurable active functional group and a functional group dissoluble in a polar solvent. The photocurable active functional group and the functional group dissoluble in a polar solvent may be located on different ligands of the same nanocrystal body, may also be located on the same ligand of the nanocrystal body, and are different chain segments on the ligand. Under ultraviolet irradiation and the action of a photoinitiator, the photocurable active functional group will undergo a polymerization reaction, and a substance formed therefrom will coat the nanocrystal body, thereby making the surface stability of the nanocrystal improved; and the performance of an electroluminescent device prepared from the nanocrystal will be significantly improved.

Description

Reactive nanocrystal, nanocrystal photolithography solution, electroluminescent nanocrystal layer and preparation method thereof, and electroluminescent device Technical Field

[0001] The present invention belongs to the field of display technology, and in particular relates to reactive nanocrystals, nanocrystal photolithography liquid, electroluminescent nanocrystal layers and preparation methods thereof, and electroluminescent devices. Background Art

[0002] As a new display technology, quantum dot light-emitting diodes (QLEDs) offer excellent properties, including narrow emission bandwidth, high luminous efficiency, tunable emission wavelength, wide color gamut, and excellent photostability. Importantly, QLEDs, based on nanometer-sized quantum dots (QDs), theoretically exhibit performance unaffected by pixel size, making them suitable for the manufacture of high-resolution displays. QLED pixel patterns are primarily achieved through techniques such as inkjet printing (IJP), transfer printing, and photolithography.

[0003] Because quantum dots are inorganic nanoparticles, the industry generally believed that QLED mass production would rely on inkjet printing. Due to the precision limitations of inkjet printing, its application was generally considered limited to large-scale display products with resolutions of 300 PPI or less. The inkjet printing (IJP) process not only faces the enormous challenge of creating small pixels smaller than tens of microns, but also faces difficulties in controlling the diffusion of solid nanoparticles within the confined space of the ink. Furthermore, the impact of three-phase contact line pinning on film formation during the ink drying process can lead to uneven quantum dot films and poor device performance.

[0004] Although transfer printing has shown unique potential in fabricating ultrasmall pixels, sagging and peeling of the elastic stamp inevitably affect the morphology and quality of the film. Especially at ultrasmall scales, precise alignment of the stamp faces enormous challenges, making it difficult to fabricate high-resolution full-color devices.

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

[0006] The current method of preparing electro-QLED devices through patterning technology has the problem of destroying quantum dots. For example, in the patent application publication number CN 114958072 A, when the quantum dot layer is exposed to ultraviolet light, a photoacid generator is used to catalyze the cross-linking reaction between the cross-linker in the quantum dot ink and the organic ligand. However, when the quantum dot layer is exposed to ultraviolet light, the photoacid generator releases acidic protons, which are very unfriendly to quantum dots and destroy the luminous efficiency of the quantum dots, resulting in a low maximum external quantum efficiency of the electro-QLED device. This method is still not suitable for mass production of electro-QLED devices prepared by patterning technology.

[0007] Therefore, there is an urgent need to develop a new electro-QLED pixel patterning technology that is suitable for mass production of electro-QLED devices.

[0008] Summary of the Invention

[0009] In view of this, one of the objects of the present invention is to provide a reactive nanocrystal comprising a nanocrystal body and an organic chain segment connected to the surface of the nanocrystal body, wherein the organic chain segment comprises a photocurable active functional group and a functional group soluble in a polar solvent. The polar solvent herein comprises 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.

[0010] As a preferred embodiment of the above-mentioned reactive nanocrystals, the photocurable active functional group includes a substituted or unsubstituted acrylic group.

[0011] As a preferred embodiment of the above-mentioned reactive nanocrystals, the functional group soluble in polar solvents includes at least one of an ester group, an ether group, a hydroxyl group, an amine group, and an amide group.

[0012] As a preferred embodiment of the reactive nanocrystals, the organic chain segments are at least one of pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate.

[0013] As a preferred embodiment of the reactive nanocrystals, in the reactive nanocrystals, the weight percentage of the organic chain segments is 5-80 wt %.

[0014] A second object of the present invention is to provide a nanocrystal photoresist 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 exposure to light, the nanocrystal photoresist undergoes a polymerization reaction between the photocurable active functional groups on the surfaces of the reactive nanocrystals.

[0015] As a preferred embodiment of the nanocrystal photoresist, the reactive nanocrystals comprise 1-20 wt %, the polar solvent comprises 70-99 wt %, and the photoinitiator comprises 0.01-0.2 wt %, based on the weight percentages of the components in the nanocrystal photoresist. The inventors have discovered that this composition allows for the production of excellent device performance during patterning.

[0016] As a preferred embodiment of the above-mentioned 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.

[0017] The third object of the present invention is to provide an electroluminescent nanocrystal layer prepared by photolithography using the above-mentioned nanocrystal photolithography solution.

[0018] A fourth object of the present invention is to provide a method for preparing an electroluminescent nanocrystal layer, comprising the steps of:

[0019] S1, dispersing initial nanocrystals and an organic compound in a first solvent, and reacting to obtain the above-mentioned reactive nanocrystals, wherein the organic compound contains a photocurable active functional group and a functional group soluble in a polar solvent;

[0020] S2, dispersing the reactive nanocrystals and photoinitiator in a polar solvent to form a photoresist solution;

[0021] S3, coating the photoresist on the substrate, and performing photolithography to obtain a patterned nanocrystal layer.

[0022] Preferably, the reaction in S1 is carried out under an inert atmosphere, at a reaction temperature of 25-150° C., and for a reaction time of 0.5-48 hours.

[0023] As a preferred solution of the above-mentioned method for preparing the electroluminescent nanocrystal layer, the photolithography includes sequentially subjecting the photoresist to the processes of exposure, development, and drying.

[0024] A fifth object of the present invention is to provide an electroluminescent device comprising the above-mentioned electroluminescent nanocrystal layer or the electroluminescent nanocrystal layer prepared by the above-mentioned method.

[0025] Compared with the prior art, the present invention has at least the following advantages:

[0026] 1. The reactive nanocrystals of the present invention are formed by connecting organic chain segments to the surface of the nanocrystal body. The organic chain segments contain photocurable active functional groups and polar solvent-soluble functional groups. The photocurable active functional groups and polar solvent-soluble functional groups can be located on different ligands on the same nanocrystal, or on the same ligand on the nanocrystal, but are different chain segments on the ligand. Under ultraviolet light irradiation and the action of a photoinitiator, a polymerization reaction occurs between the photocurable active functional groups, and the resulting substance coats the nanocrystal body, thereby achieving the purpose of cross-linking the nanocrystal body.

[0027] 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 photoresist. During patterning, spin coating, exposure and development can be carried out directly, avoiding the desizing step in traditional photolithography methods. The method is simple and reliable.

[0028] 3. The nanocrystals also have functional groups that are soluble in polar solvents, which greatly improves their compatibility and solubility with polar solvents, and has a low-cost advantage in mass production;

[0029] 4. The construction of multi-layer patterned nanocrystal layers only requires repeated spin coating, exposure and development steps, which makes it easy to construct multi-nanocrystalline layer patterned devices with full red, green and blue colors.

[0030] 5. The electroluminescent nanocrystal layer of the present invention is used to prepare full-color QLED devices. Compared with the sub-pixel sizes of tens of microns or larger constructed by current inkjet printing, the present invention easily obtains high-resolution devices with sub-pixel widths as small as submicron level and very high maximum external quantum efficiency, which are suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] FIG1 is a diagram showing the relationship between brightness and EQE of a red QLED device according to Example 1 of the present invention;

[0033] FIG2 is a diagram showing the relationship between voltage and EQE of the red QLED device according to Example 1 of the present invention;

[0034] FIG3 is a schematic diagram of lighting the red QLED device according to Example 1 of the present invention;

[0035] FIG4 is a film surface diagram of an electroluminescent nanocrystal layer of a red QLED device according to Example 1 of the present invention;

[0036] FIG5 is a diagram showing the relationship between brightness and EQE of a green QLED device according to Example 2 of the present invention;

[0037] FIG6 is a diagram showing the relationship between voltage and EQE of a green QLED device according to Example 2 of the present invention;

[0038] FIG7 is a schematic diagram of lighting a green QLED device according to Example 2 of the present invention;

[0039] FIG8 is a film surface diagram of an electroluminescent nanocrystal layer of a green QLED device according to Example 2 of the present invention;

[0040] FIG9 is a diagram showing the relationship between brightness and EQE of a blue QLED device according to Example 3 of the present invention;

[0041] FIG10 is a diagram showing the relationship between voltage and EQE of a blue QLED device according to Example 3 of the present invention;

[0042] FIG11 is a schematic diagram of lighting a blue QLED device according to Example 3 of the present invention;

[0043] FIG12 is a film surface diagram of an electroluminescent nanocrystal layer of a blue QLED device according to Example 3 of the present invention;

[0044] FIG13 is a graph showing the relationship between the brightness and EQE of the R-QLED in the QLED device of Example 4 of the present invention;

[0045] FIG14 is a graph showing the relationship between the brightness and EQE of the G-QLED in the QLED device of Example 4 of the present invention;

[0046] FIG15 is a schematic diagram of lighting a QLED device according to Example 4 of the present invention;

[0047] FIG16 is a spectrum diagram of the G-QLED in the QLED device of Example 4 of the present invention;

[0048] FIG17 is a spectrum diagram of the R-QLED in the QLED device of Example 4 of the present invention;

[0049] FIG18 is a film surface diagram of the electroluminescent nanocrystal layer of the R-QLED in the QLED device of Example 4 of the present invention;

[0050] FIG19 is a film surface view of the electroluminescent nanocrystal layer of the G-QLED in the QLED device of Example 4 of the present invention;

[0051] FIG20 is a graph showing the relationship between the brightness and EQE of the R-QLED in the QLED device of Example 5 of the present invention;

[0052] FIG21 is a graph showing the relationship between the brightness and EQE of the G-QLED in the QLED device of Example 5 of the present invention;

[0053] FIG22 is a diagram showing the relationship between the brightness and EQE of a B-QLED in the QLED device of Example 5 of the present invention;

[0054] FIG23 is a schematic diagram of lighting the QLED device according to Example 5 of the present invention;

[0055] FIG24 is a spectrum diagram of the R-QLED in the QLED device of Example 5 of the present invention;

[0056] FIG25 is a spectrum diagram of the G-QLED in the QLED device of Example 5 of the present invention;

[0057] FIG26 is a spectrum diagram of a B-QLED in the QLED device of Example 5 of the present invention;

[0058] FIG27 is a film surface view of the electroluminescent nanocrystal layer of the R-QLED in the QLED device of Example 5 of the present invention;

[0059] FIG28 is a surface view of the electroluminescent nanocrystal layer of the G-QLED in the QLED device of Example 5 of the present invention;

[0060] FIG29 is a film surface view of the electroluminescent nanocrystal layer of the B-QLED in the QLED device of Example 5 of the present invention;

[0061] FIG30 is a surface view of the electroluminescent nanocrystal layer of the R-QLED of Comparative Example 1 of the present invention;

[0062] FIG31 is a surface view of the electroluminescent nanocrystal layer of the G-QLED of Comparative Example 2 of the present invention;

[0063] FIG32 is a film surface diagram of the electroluminescent nanocrystal layer of the B-QLED of comparative example 3 of the present invention. DETAILED DESCRIPTION

[0064] The following will describe the technical solutions in the embodiment in detail in conjunction with the embodiments of the present invention. It should be noted that the embodiments are only partial, not complete.

[0065] As used herein, for example, "at least one of" when preceding or following a list of elements modifies the entire list of elements without modifying the individual elements of the list. If not otherwise defined, all terms (including technical and scientific terms) in the specification may be defined as those skilled in the art would normally understand. Terms defined in commonly used dictionaries should be interpreted as being consistent with their meanings in the context of the relevant art and the present disclosure, and should not be interpreted in an ideal manner or too broadly unless clearly defined. In addition, unless explicitly described to the contrary, the phrases "comprise" and "comprising" 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 phrases will be understood to mean including the stated elements, but not excluding any other elements.

[0066] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. The term "or" means "and / or."

[0067] 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 sections, these elements, components, regions, layers and / or sections should not be limited by these terms.

[0068] As used herein, "about" or "approximately" is inclusive of the stated value and means within an acceptable range of deviation for the particular 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 particular quantity (i.e., the limitations of the measurement system). For example, "about" can mean that the deviation from the stated value is within one or more standard deviations, or within ±10%, ±5%.

[0069] Since the surface of quantum dots is usually ligands such as oleic acid or oleylamine, its surface properties limit the solubility of quantum dots in traditional photoresists, resulting in poor compatibility. As a result, when patterning the preparation of electro-QLED devices, a large amount of photoresist needs to be used to dissolve enough quantum dots, and in the patterning process of the quantum dot layer, a large amount of organic solvent needs to be used to dissolve the photoresist for coating and development after exposure. A large amount of photoresist and a large amount of organic solvent increase the cost and cause environmental problems. Therefore, in a preferred embodiment of the present invention, a reactive nanocrystal is provided, comprising a nanocrystal body and an organic chain segment connected to the surface of the nanocrystal body, the organic chain segment comprising a photocurable active functional group and a functional group soluble in a polar solvent. It is understandable that the photocurable active functional group of the present invention and the functional group soluble in a polar solvent can be located on different ligands of the same nanocrystal body, or can be located on the same ligand and be different segments on the ligand.

[0070] Specifically, the photocurable active functional group includes a substituted or unsubstituted acrylic group, such as an acrylic acid group provided at the end of an organic chain segment. The photocurable active functional group can be derived from an acrylic acid-acrylate copolymer. That is, an acrylic acid copolymer is used as a crosslinking agent to form a network molecule in the form of a covalent bond forming a carbon-carbon double bond. The covalent bond effect is relatively strong, and the crosslinked network structure is stable. Under ultraviolet light irradiation and the action of a photoinitiator, the double bond in the photocurable active functional group will undergo a polymerization reaction, and the resulting substance will coat the nanocrystal body, thereby improving the stability of the nanocrystal surface. The resolution and maximum external quantum efficiency of the nanocrystal electrochemical device prepared from the nanocrystal will be significantly improved.

[0071] The photoinitiator here includes at least one of ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone, methyl benzoylformate, 2,4-dihydroxybenzophenone, diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, and 5-nitroacenaphthene.

[0072] Particularly, the functional group that can be dissolved in polar solvent of the present invention comprises at least one of ester group, ether group, hydroxyl, amino group, amide group, and such group makes the organic chain segment that is connected to the nanocrystal body surface be easy to be dissolved in polar solvent.The polar solvent here comprises 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, and is the organic solvent with larger polarity.This nanocrystal carries the functional group that can be dissolved in polar solvent, greatly improved the solubility with above-mentioned polar solvent.

[0073] Specifically, the organic chain segments on the surface of the nanocrystal body of the present invention contain at least one of thiol, carboxyl, amine, and amide groups, so as to facilitate coordination and connection with the surface of the nanocrystal body.

[0074] In one embodiment, the weight percentage of the organic chain segments in the reactive nanocrystals of the present invention is 5-80 wt%, preferably 10-30 wt%. The electroluminescent nanocrystal layer prepared using the reactive nanocrystals has excellent stability.

[0075] Preferably, the organic chain segment is at least one of pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate.

[0076] Since the nanocrystals of the present invention have active functional groups that can be photocured and functional groups that can be dissolved in polar solvents, when patterning to form QLED devices, it is only necessary to mix the nanocrystals, polar solvents and photoinitiators without adding monomers, resins, etc., and can be directly spin-coated, exposed and developed, eliminating the debonding step in traditional photolithography methods. The method is simple and reliable.

[0077] The present invention also provides a nanocrystal photolithography solution comprising a mother liquor and the above-mentioned reactive nanocrystals dispersed in the mother liquor, wherein the mother liquor comprises a polar solvent and a photoinitiator. Upon exposure to light, the nanocrystal photolithography solution undergoes a polymerization reaction between the photocurable active functional groups on the surfaces of the reactive nanocrystals. The polymerization reaction of the present invention can be a polymerization reaction between the photocurable active functional groups on the surface of the same nanocrystal, a polymerization reaction between the photocurable active functional groups on the surfaces of different nanocrystals, or a simultaneous polymerization of the two aforementioned polymerization reactions, resulting in the surface of the nanocrystal 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.

[0078] In a specific embodiment of the present invention, the formula of the nanocrystal photoresist is calculated based on the weight percentage of each component in the nanocrystal photoresist, and the content of the reactive nanocrystals is 1-20wt%, the content of the polar solvent is 70-99wt%, and the content of the photoinitiator is 0.01-0.2wt%. The reactive nanocrystals have 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 chain segments on the surface of the reactive nanocrystals will undergo a polymerization reaction to form a nanocrystal photoresist that is easy to spin-coat.

[0079] The present invention also provides an electroluminescent nanocrystal layer obtained by photolithography using the aforementioned nanocrystal photoresist. Under ultraviolet light irradiation, the reactive organic chains on the surface of the nanocrystals in the nanocrystal photoresist undergo polymerization, forming a thin layer of polymer on the surface of the nanocrystals to protect the surface. The polar solvent is then evaporated, resulting in an electroluminescent nanocrystal layer with excellent photoelectric properties.

[0080] The present invention also provides a method for preparing the electroluminescent nanocrystal layer, comprising the steps of:

[0081] S0. Preparation of initial nanocrystals.

[0082] In the present invention, the initial nanocrystals include at least one of a II-VI compound, a III-V compound, and a perovskite nanocrystal. For example, the II-VI compound 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. The III-V compound 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 a combination thereof. The perovskite nanocrystal includes organic perovskite nanocrystals and / or inorganic perovskite nanocrystals, and the perovskite nanocrystals may be commercially available products.

[0083] The initial nanocrystals are prepared by the existing solution method and purified, which will not be described in detail here.

[0084] S1. Dispersing initial nanocrystals and an organic compound in a first solvent to react to obtain surface-modified nanocrystals, wherein the organic compound comprises a photocurable active functional group and a functional group soluble in a polar solvent.

[0085] The reaction temperature of the initial nanocrystals and the organic compound of the present invention is 20-120° C., so that the organic compound is combined with the surface of the initial nanocrystals to obtain nanocrystals with reactive activity.

[0086] S2. Dispersing reactive nanocrystals and photoinitiators in a polar solvent to form a photoresist solution.

[0087] S3, coating the photoresist on the substrate, and performing photolithography to obtain a patterned nanocrystal layer.

[0088] Preferably, the reaction in step S1 is carried out under an inert atmosphere at a temperature of 25-150° C. for a time of 0.5-48 hours. The first solvent comprises at least one of xylene, toluene, and trimethylbenzene, which can better dissolve the initial nanocrystals and organic compounds and promote efficient reaction.

[0089] The feeding ratio of the initial nanocrystals and the organic compound in step S1 is 100:(5-200), so as to better perform the subsequent photolithography process and obtain an electroluminescent device with better optical performance.

[0090] Preferably, the mixing temperature in step S2 is 20-120° C., and the mixing time is 1-20 hours.

[0091] In a specific embodiment of the present invention, photolithography includes sequentially exposing, developing, and drying the photoresist. Compared to conventional photolithography processes in the prior art, the photolithography process of the present invention does not include a step of pre-baking the nanocrystalline photoresist in order to avoid inactivation of reactive nanocrystals. Exposure refers to irradiating the nanocrystalline photoresist under ultraviolet light for 10-40 seconds under the protection of a mask. Development is the process of rinsing the exposed nanocrystalline photoresist with a polar solvent for 30-500 seconds. Drying is the process of baking at 70-150°C for 5-50 minutes.

[0092] It can be understood that the nanocrystal body of the reactive nanocrystal of the present invention comes from the initial nanocrystal, that is, the nanocrystal body of the reactive nanocrystal of the present invention is the initial nanocrystal.

[0093] The present invention also provides an electroluminescent device comprising the electroluminescent nanocrystal layer or the electroluminescent nanocrystal layer prepared by the above method. The electroluminescent device has stable light emission, high brightness and resolution, and can achieve an external quantum efficiency of 1-30%.

[0094] The present invention adopts a nanocrystal direct photolithography patterning process, breaking through the resolution limitations of traditional evaporation and inkjet printing processes. Its resolution theoretically depends on the accuracy of the exposure machine and the mask. In principle, it can even obtain sub-micron pattern line widths and reach a pixel density of more than 10,000 PPI.

[0095] Nanocrystal direct lithography can achieve highly free size and pixel density specification combinations, highly free pixel arrangement design, higher aperture ratio and device life, simpler process and more flexible and efficient product development in the full-size field. It has greatly promoted the commercialization of QLED technology in the medium and small-size panel market and the micro-display market, helping to achieve full-size coverage of QLED technology in the display field and bring customers the ultimate visual experience.

[0096] Some exemplary embodiments according to the present invention are described in more detail below; however, exemplary embodiments of the present invention are not limited thereto.

[0097] Example 1

[0098] Synthesis of S0 and red-light CdZnSe / ZnCdS / ZnS nanocrystals

[0099] Anion precursor preparation: 10 mmol of selenium powder was mixed thoroughly with tri-n-octylphosphine to obtain a selenium source precursor (Se-TOP, 2M); 10 mmol of sulfur powder was mixed thoroughly with tri-n-octylphosphine to obtain a sulfur source precursor (S-TOP, 2M).

[0100] Cationic precursor preparation: take 10 mmol of anhydrous zinc acetate, add 10 ml of oleic acid, 10 ml of octadecene, evacuate at 120°C until there are no bubbles, pass N2, keep warm at 100°C for use, and obtain zinc oleate precursor (0.5 M); take 10 mmol of cadmium oxide, add 12 ml of oleic acid, 38 ml of octadecene, evacuate at 120°C until there are no bubbles, pass N2, heat to 240°C, maintain for 60 minutes, and cool to obtain cadmium oleate precursor (0.2 M).

[0101] Synthesis of red-light CdZnSe / ZnCdS / ZnS nanocrystals: Mix 6 mmol of zinc oleate and 6 mmol of cadmium oleate, evacuate the mixture three times, and heat to 320°C with nitrogen. Rapidly inject 6 ml of Se-TOP solution, allow to react for 60 minutes, cool to 280°C, add 12 mmol of zinc oleate, and dropwise add 3 ml of S-TOP solution (2 M, a sulfur precursor formed by dissolving sulfur powder in trioctylphosphine) and 6 mmol of cadmium oleate. Allow to react for 40 minutes. Finally, add 20 mmol of zinc oleate and dropwise add 6 ml of dodecanethiol, allowing to react for 60 minutes. Cool to room temperature, precipitate, and purify the product with n-heptane and ethanol to obtain CdZnSe / ZnCdS / ZnS nanocrystals.

[0102] S1. Preparation of reactive nanocrystals:

[0103] 100 mg of red-light CdZnSe / ZnCdS / ZnS nanocrystals and 5 mg of pentaerythritol tetrakis (3-mercaptopropionate) were added to 1 ml of xylene and reacted at 80°C for 30 minutes under a nitrogen environment. Then, 5 mg of acrylic acid-acrylate copolymer was added and reacted at 60°C for 60 minutes. Then, 5 mg of succinic acid mono-[2-[(2-methyl-acryloyl)oxy]ethyl] ester was added and reacted at 120°C for 60 minutes to obtain a reactive nanocrystal solution. The reactive nanocrystal solution was vacuum dried to remove the xylene to obtain reactive nanocrystals.

[0104] S2. Preparation of photoresist:

[0105] The 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 an initial photoresist solution.

[0106] The initial photoresist solution was centrifuged for 10 minutes, and the supernatant was collected and filtered three times using a 0.22 μm filter to obtain the photoresist solution.

[0107] S3. Preparation of QLED devices:

[0108] 1) A 45 nm thick polyethylenedioxythiophene-poly(styrenesulfonate) (PEDOT:PSS) layer and a 40 nm thick poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer were sequentially prepared on an indium tin oxide glass (first electrode);

[0109] 2) Spin-coating the above-mentioned photoresist onto the TFB layer, exposing (under UV light for 50 seconds under the protection of a mask), developing (immersing in developer and then rinsing with PGMEA), and baking at 120°C for 20 minutes to obtain a 25 nm thick nanocrystalline layer;

[0110] 3) A 65nm thick zinc oxide (ZnO) layer was prepared on the nanocrystalline layer; an Al cathode layer was evaporated on the ZnO layer, and then packaged to form a red QLED device (R-QLED). The optical parameters of the red QLED device are as follows:

[0111] It can be seen that the red light QLED device starts normally at a voltage of 2.0V, with a maximum external quantum efficiency of 27.4%. At a voltage of 4V, the brightness reaches 41800nits.

[0112] As shown in FIG1 , the relationship between the brightness and EQE of the red QLED device shows that the external quantum efficiency changes smoothly with the increase of brightness.

[0113] As shown in FIG2 , the relationship between voltage and EQE of the red QLED device shows that the external quantum efficiency changes smoothly with increasing voltage.

[0114] As shown in FIG3 , the red QLED device is in a lit state and has uniform light output.

[0115] As shown in FIG4 , the surface of the electroluminescent nanocrystal layer of the red QLED device has a very good film surface flatness.

[0116] Example 2

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

[0118] Anion precursor preparation: 10 mmol of selenium powder was mixed thoroughly with tri-n-octylphosphine to obtain a selenium source precursor (Se-TOP, 2M); 10 mmol of sulfur powder was mixed thoroughly with tri-n-octylphosphine to obtain a sulfur source precursor (S-TOP, 2M).

[0119] Cationic precursor preparation: Take 10 mmol of anhydrous zinc acetate, add 10 ml of oleic acid and 10 ml of octadecene, evacuate at 120°C until no bubbles appear, purge with N2, and maintain at 100°C until ready for use. This yields a zinc oleate precursor (0.5 M). Take 10 mmol of cadmium oxide, add 12 ml of oleic acid and 38 ml of octadecene, evacuate at 120°C until no bubbles appear, purge with N2, raise the temperature to 240°C, hold for 60 minutes, and then cool to yield a cadmium oleate precursor (0.2 M).

[0120] Synthesis of green-light CdZnSeS / ZnS nanocrystals: Mix 20 mmol of zinc oleate and 1 mmol of cadmium oleate, evacuate the mixture three times, and heat to 320°C under nitrogen. Rapidly inject 5 ml of a mixture of Se-TOP and 5 ml of S-TOP. Allow to react for 30 minutes. Cool to 240°C, add 10 mmol of zinc oleate, and dropwise add 3 ml of dodecanethiol. Allow to react for 60 minutes. Cool to room temperature, and precipitate and purify the product with n-heptane and ethanol to obtain CdZnSeS / ZnS nanocrystals.

[0121] S1. Preparation of reactive nanocrystals:

[0122] 100 mg of green light CdZnSeS / ZnS nanocrystals and 10 mg of pentaerythritol tetrakis (3-mercaptopropionate) were added to 1 ml of xylene and reacted at 80°C in a nitrogen environment for 60 minutes. Then, 8 mg of acrylic acid-acrylate copolymer was added and reacted at 60°C for 60 minutes. Then, 5 mg of succinic acid 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 the reactive nanocrystal solution was vacuum dried to remove the xylene, reactive nanocrystals were obtained.

[0123] S2. Preparation of photoresist:

[0124] The 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 an initial photoresist solution.

[0125] After centrifuging the initial photoresist solution for 10 minutes, the supernatant was collected and filtered three times using a 0.22 μm filter to obtain the photoresist solution.

[0126] S3. Preparation of QLED devices:

[0127] 1) A 45 nm thick polyethylenedioxythiophene-poly(styrenesulfonate) (PEDOT:PSS) layer and a 40 nm thick poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer were sequentially prepared on an indium tin oxide glass (first electrode);

[0128] 2) Spin-coating the above-mentioned photoresist onto the TFB layer, exposing (under UV light for 50 seconds under the protection of a mask), developing (immersing in developer and then rinsing with PGMEA), and baking at 120°C for 20 minutes to obtain a 25 nm thick nanocrystalline layer;

[0129] 3) A 65nm thick zinc oxide (ZnO) layer was prepared on the nanocrystalline layer; an Al cathode layer was evaporated on the ZnO layer, and then packaged to form a green QLED device (G-QLED). The optical parameters of the green QLED device are as follows:

[0130] It can be seen that the green light QLED device starts normally at a voltage of 2.4V, with a maximum external quantum efficiency of 9.6%. At a voltage of 4V, the brightness reaches 96980nits.

[0131] As shown in FIG5 , the relationship between the brightness and EQE of the green QLED device shows that the external quantum efficiency changes smoothly with the increase of brightness.

[0132] As shown in FIG6 , the relationship between voltage and EQE of the green QLED device shows that the external quantum efficiency changes smoothly with increasing voltage.

[0133] As shown in FIG7 , the green QLED device is in a lit state, and it can be seen that the light output is uniform.

[0134] As shown in FIG8 , the surface of the electroluminescent nanocrystal layer of the green QLED device has good flatness.

[0135] Example 3

[0136] Synthesis of S0 and blue-light CdZnSeS / ZnS nanocrystals

[0137] Anion precursor preparation: 10 mmol of selenium powder was mixed thoroughly with tri-n-octylphosphine to obtain a selenium source precursor (Se-TOP, 2M); 10 mmol of sulfur powder was mixed thoroughly with tri-n-octylphosphine to obtain a sulfur source precursor (S-TOP, 2M).

[0138] Cationic precursor preparation: take 10 mmol of anhydrous zinc acetate, add 10 ml of oleic acid, 10 ml of octadecene, evacuate at 120°C until there are no bubbles, pass N2, keep warm at 100°C for use, and obtain zinc oleate precursor (0.5 M); take 10 mmol of cadmium oxide, add 12 ml of oleic acid, 38 ml of octadecene, evacuate at 120°C until there are no bubbles, pass N2, heat to 240°C, maintain for 60 minutes, and cool to obtain cadmium oleate precursor (0.2 M).

[0139] Synthesis of blue-light CdZnSeS / ZnS nanocrystals: 20 mmol of zinc oleate and 1 mmol of cadmium oleate were mixed, evacuated three times, heated to 320°C with N2, and 1 ml of Se-TOP and 9 ml of S-TOP mixture were quickly injected. The reaction was carried out for 30 minutes, and the temperature was 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 obtain CdZnSeS / ZnS nanocrystals.

[0140] S1. Preparation of reactive nanocrystals:

[0141] 100 mg of blue light CdZnSeS / ZnS nanocrystals and 10 mg of pentaerythritol tetrakis (3-mercaptopropionate) were added to 1 ml of xylene and reacted at 80°C in a nitrogen environment for 60 minutes. Then, 6 mg of acrylic acid-acrylate copolymer was added and reacted at 60°C for 60 minutes. Then, 4 mg of succinic acid 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 the reactive nanocrystal solution was vacuum dried to remove the xylene, reactive nanocrystals were obtained.

[0142] S2. Preparation of photoresist solution:

[0143] The reactive nanocrystals were added to 5 ml of PGMEA, stirred evenly, and then 2 mg of TPO was added, and stirred evenly at 60° C. in the dark to obtain an initial photoresist solution.

[0144] The initial photoresist solution was centrifuged at 10,000 r / min for 10 minutes, and the supernatant was collected and filtered three times using a 0.22 μm filter to obtain a photoresist solution.

[0145] S3. Preparation of QLED devices:

[0146] 1) A 45 nm thick polyethylenedioxythiophene-poly(styrenesulfonate) (PEDOT:PSS) layer and a 40 nm thick poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer were sequentially prepared on an indium tin oxide glass (first electrode);

[0147] 2) Spin-coating the above-mentioned photoresist onto the TFB layer, exposing (under UV light for 50 seconds under the protection of a mask), developing (immersing in developer and then rinsing with PGMEA), and baking at 120°C for 20 minutes to obtain a 25 nm thick nanocrystalline layer;

[0148] 3) A 65 nm thick zinc oxide (ZnO) layer was formed on the nanocrystalline layer; an Al cathode layer was evaporated on the ZnO layer, and the device was packaged to form a blue QLED device. The optical parameters of the blue QLED device (B-QLED) are shown in the following table:

[0149] It can be seen that the blue light QLED device starts normally at a voltage of 2.6V, with a maximum external quantum efficiency of 1.28%. At a voltage of 4V, the brightness reaches 6256nits.

[0150] As shown in FIG9 , the relationship between the brightness and EQE of the blue light QLED device shows that the external quantum efficiency changes smoothly with the increase of brightness.

[0151] As shown in FIG10 , the relationship between voltage and EQE of the blue QLED device shows that the external quantum efficiency changes smoothly with increasing voltage.

[0152] As shown in FIG11 , the blue light QLED device is in a lit state, and it can be seen that the light output is uniform.

[0153] As shown in FIG12 , the surface of the electroluminescent nanocrystal layer of the blue light QLED device has a very good film surface flatness.

[0154] Example 4

[0155] The preparation of the red light-emitting nanocrystals and the photoresist in this embodiment is the same as that in embodiment 1, and the preparation of the green light-emitting nanocrystals and the photoresist is the same as that in embodiment 2. The difference is that step S3 is as follows:

[0156] 1) A 45 nm thick polyethylenedioxythiophene-poly(styrenesulfonate) (PEDOT:PSS) layer and a 40 nm thick poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer were sequentially prepared on an indium tin oxide glass (first electrode);

[0157] 2) The photoresist of Example 1 was spin-coated on the TFB layer, and after UV exposure (energy 400 mJ / cm2), development (using PGMEA rinse), baking at 120°C for 20 minutes to obtain a red light nanocrystal layer with a thickness of 25 nm;

[0158] 3) The photoresist of Example 2 was spin-coated on the TFB layer, and after UV exposure (energy 300 mJ / cm2), development (using PGMEA rinse), and baking at 120°C for 20 minutes to obtain a green light nanocrystal layer with a thickness of 25 nm;

[0159] 4) A 65nm thick zinc oxide (ZnO) layer was prepared on the red and green nanocrystal layers, respectively; an Al cathode layer was evaporated on the ZnO layer, and then packaged to form a QLED device that displays red and green light on the substrate. The optical parameters of the QLED device are shown in the following table:

[0160] As shown in Figure 13, the relationship between the brightness and EQE of the red light QLED device (R-QLED) shows that as the brightness increases, the EQE of the R-QLED first decreases and then increases and remains stable; as shown in Figure 14, the relationship between the brightness and EQE of the green light QLED device (G-QLED) shows that as the brightness increases, the EQE of the G-QLED decreases slightly and then maintains a stable trend.

[0161] As shown in FIG15 , the QLED device is in a lit state and has uniform light output.

[0162] As shown in Figures 16 and 17, the spectrum of the G-QLED in the QLED device when lit at different voltages and the spectrum of the R-QLED when lit at different voltages respectively, it can be seen that the spectrum is relatively pure without interference from light in other bands.

[0163] As shown in Figures 18 and 19 respectively, the surface conditions of the electroluminescent nanocrystalline layer of the R-QLED and the electroluminescent nanocrystalline layer of the G-QLED in the QLED device, it can be seen that the film surface is very smooth.

[0164] Example 5

[0165] The preparation of the red light-emitting nanocrystals and the photoresist in this embodiment is the same as in embodiment 1, the preparation of the green light-emitting nanocrystals and the photoresist is the same as in embodiment 2, and the preparation of the blue light-emitting nanocrystals and the photoresist is the same as in embodiment 3. The difference is that step S3 is as follows:

[0166] 1) A 45 nm thick polyethylenedioxythiophene-poly(styrenesulfonate) (PEDOT:PSS) layer and a 40 nm thick poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer were sequentially prepared on an indium tin oxide glass (first electrode);

[0167] 2) The photoresist of Example 1 was spin-coated on the TFB layer, and after UV exposure (energy 400 mJ / cm2), development (using PGMEA rinse), baking at 120°C for 20 minutes to obtain a red light nanocrystal layer with a thickness of 25 nm;

[0168] 3) The photoresist of Example 2 was spin-coated on the TFB layer, and after UV exposure (energy 300 mJ / cm2), development (using PGMEA rinse), and baking at 120°C for 20 minutes to obtain a green light nanocrystal layer with a thickness of 25 nm;

[0169] 4) The photoresist of Example 3 was spin-coated on the TFB layer, and after UV exposure (energy 300 mJ / cm2), development (using PGMEA rinse), baking at 120°C for 20 minutes to obtain a blue light nanocrystal layer with a thickness of 25 nm;

[0170] 5) A 65 nm thick zinc oxide (ZnO) layer was formed on the red, green, and blue nanocrystal layers, respectively; an Al cathode layer was evaporated on the ZnO layer, and the layers were packaged to form a QLED device displaying red, green, and blue light on the substrate. The optical parameters of the QLED device are shown in the following table:

[0171] As shown in Figure 20, the relationship between the brightness and EQE of the red QLED device (R-QLED) shows that as the brightness increases, the EQE of the R-QLED changes steadily; as shown in Figure 21, the relationship between the brightness and EQE of the green QLED device (G-QLED) shows that as the brightness increases, the EQE of the G-QLED maintains a stable trend; as shown in Figure 22, the relationship between the brightness and EQE of the green QLED device (B-QLED) shows that as the brightness increases, the EQE of the B-QLED rises, maintains a stable trend, and then decreases slightly.

[0172] As shown in FIG23 , the QLED device is in a lit state and the light output is uniform.

[0173] As shown in Figures 24, 25, and 26, respectively, the spectrum diagrams of R-QLED in the QLED device when lit at different voltages, the spectrum diagrams of G-QLED when lit at different voltages, and the spectrum diagrams of B-QLED when lit at different voltages, it can be seen that the spectrum is relatively pure without interference from light in other bands.

[0174] As shown in Figures 27, 28 and 29 respectively, the surface conditions of the electroluminescent nanocrystalline layer of the R-QLED, the surface conditions of the electroluminescent nanocrystalline layer of the G-QLED and the surface conditions of the electroluminescent nanocrystalline layer of the B-QLED in the QLED device, it can be seen that the film surface is very smooth.

[0175] Comparative Example 1

[0176] On the indium tin oxide glass (first electrode), a 45nm thick polyethylene dioxythiophene-poly(styrene sulfonate) (PEDOT:PSS) layer, a 40nm thick poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl) diphenylamine) (TFB) layer, a 25nm thick R-QD layer (conventional inkjet printing), and a 65nm thick ZnO layer were spin-coated in sequence. An Al cathode layer was evaporated on the ZnO layer and encapsulated to form an R-QLED. The surface of the electroluminescent nanocrystal layer of the R-QLED is shown in Figure 30, and the film surface is rough and uneven.

[0177] Comparative Example 2

[0178] A 45nm thick polyethylenedioxythiophene-poly(styrenesulfonate) (PEDOT:PSS) layer, a 40nm thick poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer, a 25nm thick G-QD layer (conventional inkjet printing), and a 65nm thick ZnO layer were spin-coated on an indium tin oxide glass (first electrode). An Al cathode layer was evaporated on the ZnO layer and encapsulated to form a green QLED device. The surface of the electroluminescent nanocrystal layer of the G-QLED is shown in Figure 31, and the film surface is rough and uneven.

[0179] Comparative Example 3

[0180] A 45nm thick polyethylenedioxythiophene-poly(styrenesulfonate) (PEDOT:PSS) layer, a 40nm thick poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB) layer, a 25nm thick B-QD layer (conventional inkjet printing), and a 65nm thick ZnO layer were spin-coated on an indium tin oxide glass (first electrode). An Al cathode layer was evaporated on the ZnO layer and encapsulated to form a blue QLED device. The surface of the electroluminescent nanocrystal layer of the B-QLED is shown in Figure 32, and the film surface is rough and uneven.

[0181] The optical parameters of the devices of Comparative Examples 1-3 are summarized in the following table:

[0182] As can be seen, compared to the QLED devices formed from the nanocrystals prepared in Comparative Examples 1-3, the QLED devices formed from the reactive nanocrystals of Examples 1-5 of the present application have a high external quantum efficiency (EQE) that can be maintained at a high level for a longer period of time, and the electroluminescent nanocrystal layer has a better film surface flatness. The reactive nanocrystals prepared using the technical solution of the present application have excellent electrical properties, and the light-emitting devices prepared from them have excellent optoelectronic performance and high resolution, which is conducive to promoting the commercial application of optical components containing reactive nanocrystals.

[0183] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one 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 present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A reactive nanocrystal, characterized in that: The nanocrystal comprises a nanocrystal body and an organic chain segment connected to the surface of the nanocrystal body, wherein the organic chain segment comprises a photocurable active functional group and a functional group soluble in a polar solvent.

2. The reactive nanocrystal according to claim 1, characterized in that: The photocurable reactive functional group includes a substituted or unsubstituted acrylic group.

3. The reactive nanocrystal according to claim 1, characterized in that: The functional group soluble in polar solvents includes at least one of an ester group, an ether group, a hydroxyl group, an amine group, and an amide group.

4. The reactive nanocrystal according to claim 1, characterized in that: The organic chain segment is at least one of pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutyrate), and tris [2- (3-mercaptopropionyloxy) ethyl] isocyanurate.

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

6. A nanocrystalline photolithography liquid, characterized in that: The invention comprises a mother liquid and the reactive nanocrystals as claimed in any one of claims 1 to 5 dispersed in the mother liquid, wherein the mother liquid comprises a polar solvent and a photoinitiator.

7. The nanocrystalline photolithography liquid according to claim 6, characterized in that: According to the weight percentage of each component in the nanocrystal photolithography solution, the content of the reactive nanocrystals is 1-20wt%, the content of the polar solvent is 70-99wt%, and the content of the photoinitiator is 0.01-0.2wt%.

8. The nanocrystalline photolithography liquid according to claim 6, 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.

9. An electroluminescent nanocrystal layer, characterized in that: The nanocrystalline photolithography liquid is prepared by photolithography.

10. A method for preparing an electroluminescent nanocrystal layer, characterized in that: Includes steps: S1, dispersing initial nanocrystals and an organic compound in a first solvent, and reacting to obtain the reactive nanocrystals as described in any one of claims 1 to 5, wherein the organic compound comprises a photocurable active functional group and a functional group soluble in a polar solvent; S2, dispersing the reactive nanocrystals and photoinitiator in a polar solvent to form a photolithography solution; S3, coating the photolithography liquid on the substrate, and performing photolithography to obtain a patterned nanocrystalline layer.

11. The method for preparing an electroluminescent nanocrystal layer according to claim 10, characterized in that: The photolithography includes the process of sequentially exposing, developing and drying the photolithography liquid.

12. An electroluminescent device, characterized in that: The invention comprises the electroluminescent nanocrystal layer as claimed in claim 9, or the electroluminescent nanocrystal layer prepared by the method as claimed in any one of claims 10 to 11.

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