Quantum dot composition, display device, and method for patterning quantum dot film layer

Abstract

A quantum dot composition, a method for patterning a quantum dot film layer, and a quantum dot display device. The quantum dot composition comprises a mixed quantum dot material and a photosensitizer. The quantum dot material comprises a quantum dot body and a first quantum dot ligand on the surface of the quantum dot body; and the photosensitizer is configured to react with the first quantum dot ligand under illumination to form a second quantum dot ligand, wherein the molecular weight of the second quantum dot ligand is greater than that of the first quantum dot ligand, and the second quantum dot ligand and the first quantum dot ligand have different polarities. Photoetching patterning is directly carried out by utilizing the characteristic of a surface chemical property change of the quantum dot body, so that damage to the photoelectric properties of quantum dots caused by the introduction of a photoresist is avoided; in addition, the subsequent development mode is flexible. By selecting solvents having different polarities for development, a quantum dot film layer having a positive pattern or negative pattern can be obtained.

Description

Quantum dot composition, display device, and patterning method of quantum dot film layer Technical Field

[0001] Embodiments of the present disclosure relate to a quantum dot composition, a method for patterning a quantum dot film layer, and a quantum dot display device. Background Art

[0002] With the continuous development and progress of display technology, it is very important that display devices can present natural colors to the greatest extent and bring a more realistic and shocking visual experience to viewers. Among the ways to achieve a wide color gamut, one optional way is to use quantum dots (abbreviated as QD) to emit light. Quantum dot technology uses nano-scale semiconductor particles to emit light with a specific frequency by applying a certain electric field or light pressure to them. That is, in the display field, quantum dots emit light in two ways: photoluminescence and electroluminescence. The spectrum emitted by quantum dots is narrower than the half-peak width of the self-luminous spectrum of organic light-emitting diodes, and the color of the emitted light is purer and the color saturation is higher.

[0003] One specific implementation of photoluminescent quantum dots is quantum dot color film (QD-CF). QD-CF can be combined with various blue light backlight sources, such as liquid crystal display (LCD), organic light-emitting diodes (OLED), and micro light-emitting diodes (micro LED). Blue light has a shorter wavelength (430nm-470nm) and higher energy, and can excite quantum dots to emit light with a longer wavelength. This blue light then passes through a color filter composed of red and green quantum dots, stimulating the red and green quantum dots in the color filter to emit red and green light, respectively, thereby achieving full-color display.

[0004] Summary of the Invention

[0005] Embodiments of the present disclosure relate to a quantum dot composition, a method for patterning a quantum dot film layer, and a quantum dot display device. The quantum dot composition includes: a mixed quantum dot material and a photosensitizer, wherein the quantum dot material includes a quantum dot body and a first quantum dot ligand on the surface of the quantum dot body; the photosensitizer is configured to react with the first quantum dot ligand under illumination to form a second quantum dot ligand, wherein the molecular weight of the second quantum dot ligand is greater than that of the first quantum dot ligand, and the second quantum dot ligand and the first quantum dot ligand have different polarities. The embodiments of the present disclosure utilize the original ligands of the quantum dot body, eliminating the need for ligand exchange, reducing processing steps, and preserving the original properties of the quantum dots to the greatest extent possible. No photoresist process is required, the principle of this solution is simple, and the quantum dot composition consists only of quantum dots and a photosensitizer, making this method universally applicable. Photosensitizers can achieve patterning for quantum dots and ligands with different component structures. Depending on the change in polarity, they can be designed as positive photoresist compositions, that is, the quantum dot materials in the illuminated area are developed away; they can also be designed as negative photoresist compositions, that is, the quantum dot materials in the non-illuminated area are developed away.

[0006] At least one embodiment of the present disclosure provides a quantum dot composition, which includes: a mixed quantum dot material and a photosensitizer, wherein the quantum dot material includes a quantum dot body and a first quantum dot ligand on the surface of the quantum dot body; the photosensitizer is configured to react with the first quantum dot ligand under light to form a second quantum dot ligand, the molecular weight of the second quantum dot ligand is greater than the molecular weight of the first quantum dot ligand, and the second quantum dot ligand and the first quantum dot ligand have different polarities.

[0007] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the polarity index of the second quantum dot ligand is greater than or equal to 0 and less than 3.6, and correspondingly, the polarity index of the first quantum dot ligand is greater than 3.6 and less than 13; or, the polarity index of the first quantum dot ligand is greater than or equal to 0 and less than 3.6, and correspondingly, the polarity index of the second quantum dot ligand is greater than 3.6 and less than 13.

[0008] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the first quantum dot ligand includes a coordination group combined with the surface of the quantum dot body, a first connecting group connected to the coordination group, and a first functional group connected to the first connecting group; the photosensitizer includes a photosensitizing group, a second connecting group connected to the photosensitizing group, and a second functional group connected to the second connecting group; the first functional group and the second functional group have different polarities.

[0009] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the first quantum dot ligand includes a CH bond, and the photosensitive group is configured to undergo a carbon-hydrogen insertion reaction with the CH bond included in the first quantum dot ligand under light to form the second quantum dot ligand.

[0010] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the photosensitive group forms at least one of a nitrogen carbene, a carbonyl radical and a carbene under light irradiation, and at least one of the nitrogen carbene, the carbonyl radical and the carbene undergoes a carbon-hydrogen insertion reaction with the CH bond included in the first quantum dot ligand to form the second quantum dot ligand.

[0011] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the photosensitive group includes at least one of azide, benzophenone, and diazirine.

[0012] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the quantum dot ligand includes a C=C bond, and the photosensitive group is configured to undergo an addition reaction with the C=C bond included in the first quantum dot ligand under light to form the second quantum dot ligand.

[0013] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the photosensitive group forms a nitrogen carbene under light irradiation, and the nitrogen carbene undergoes an addition reaction with the C=C bond included in the first quantum dot ligand to form the second quantum dot ligand.

[0014] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the photosensitive group includes azide.

[0015] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the coordinating group includes at least one of a thiol group, a carboxyl group, an amino group, a phosphino group and a phosphinooxy group; the first linking group includes at least one of a C1-C30 straight-chain alkyl group, an unsaturated hydrocarbon chain having one or more double bonds or benzene rings, and a polyether segment compound; the first functional group includes at least one of a methyl group, a phenyl group, a sulfonic acid group, a carboxyl group, a nitroso group, a cyano group, a hydroxyl group, an amide, a phenolic hydroxyl group, a thiol group, an amino group, an aldehyde group, a carbonyl group, an alkenyl group, an alkynyl group, an ether bond and a thioether bond.

[0016] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the second linking group includes a straight-chain alkyl group of C1 to C30, an unsaturated hydrocarbon chain having one or more double bonds or a benzene ring; the second functional group includes at least one of a sulfonic acid, a carboxyl group, a nitroso group, a cyano group, a hydroxyl group, an amide group, a phenolic hydroxyl group, a thiol group, an amino group, a methyl group, an aldehyde group, an alkyl group, a carbonyl group, an alkenyl group, an alkynyl group, an ether bond and a thioether bond.

[0017] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the second functional group is at least one of sulfonic acid, carboxyl, nitroso, cyano, hydroxyl, amide, phenolic hydroxyl, thiol and amino, and the first functional group is at least one of methyl, aldehyde, carbonyl, alkenyl, alkynyl, ether bond and thioether bond; or the second functional group is at least one of methyl, aldehyde, alkyl, carbonyl, alkenyl, alkynyl, ether bond and thioether bond, and the first functional group is at least one of phenyl, sulfonic acid, carboxyl, nitroso, cyano, hydroxyl, amide, phenolic hydroxyl, thiol and amino.

[0018] For example, the quantum dot composition provided in at least one embodiment of the present disclosure further includes a solvent, wherein the solvent is a weak polar solvent or a non-polar solvent, the first functional group is a weak polar group or a non-polar group, the corresponding second functional group is a strong polar group, and the dielectric constant of the weak polar solvent or the non-polar solvent is less than 3.6.

[0019] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the first quantum dot ligand is 1-octanethiol or oleic acid, the photosensitizer is 2,3,4,5-tetrafluoro-4-azidobenzoic acid or 3-benzoylbenzoic acid, and the solvent is the weak polar solvent or the non-polar solvent.

[0020] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the weakly polar solvent or non-polar solvent includes at least one of cyclohexane, petroleum ether, octane, trimethylpentane, carbon tetrachloride, trichlorotrifluoroethane, p-xylene, chlorobenzene, o-dichlorobenzene, ether, diethyl ether, tetrahydrofuran, hexane, pentane, toluene and chlorobenzene.

[0021] For example, the quantum dot composition provided in at least one embodiment of the present disclosure further includes a solvent, wherein the solvent is a strongly polar solvent, the first functional group is a strongly polar group, the corresponding second functional group is a weakly polar group or a non-polar group, and the dielectric constant of the strongly polar solvent is greater than or equal to 3.6.

[0022] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the first quantum dot ligand is 6-mercaptohexanol, the photosensitizer is 2,3,4,5-tetrafluoro-4-azidooctadecylbenzene, and the solvent is the highly polar solvent.

[0023] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the highly polar solvent includes at least one of methanol, ethanol, isopropanol, ethyl acetate, acetonitrile, acetone, acetic acid, pyridine, N,N-dimethylformamide and dimethyl sulfoxide.

[0024] At least one embodiment of the present disclosure also provides a method for patterning a quantum dot film layer, which includes: providing a substrate; applying the quantum dot composition described in any of the above embodiments on the substrate to form a quantum dot film; using a mask to block the quantum dot film, and using light to irradiate a partial area of ​​the quantum dot film to increase the molecular weight of the quantum dot ligand in the partial area and change the polarity of the quantum dot ligand; and using a developer to develop the quantum dot film to obtain a patterned quantum dot film layer.

[0025] For example, in the patterning method of the quantum dot film layer provided in at least one embodiment of the present disclosure, light is used to irradiate a partial area of ​​the quantum dot film to increase the molecular weight of the quantum dot ligand in the partial area and change the polarity of the quantum dot ligand, including: using a mask plate to block the quantum dot film, and using ultraviolet light or infrared light to irradiate a partial area of ​​the quantum dot film, so that the molecular weight of the quantum dot ligand in the partial area irradiated by ultraviolet light or infrared light increases and forms the second quantum dot ligand.

[0026] For example, in the patterning method of the quantum dot film layer provided in at least one embodiment of the present disclosure, developing the quantum dot film with a developer to obtain a patterned quantum dot film layer includes: using a negative developer to remove the quantum dot film in the area other than the illuminated area to obtain a patterned quantum dot film layer; or using a positive developer to remove the quantum dot film in the illuminated area to obtain a patterned quantum dot film layer.

[0027] For example, in the patterning method of the quantum dot film layer provided in at least one embodiment of the present disclosure, the polarity of the quantum dot ligand is less than the polarity of the photosensitizer, and the formation of the patterned quantum dot film layer includes: using a non-polar negative developer to remove the quantum dot film in the area other than the irradiated area to obtain the patterned quantum dot film layer; or using a polar positive developer to remove the quantum dot film in the irradiated area to obtain the patterned quantum dot film layer.

[0028] For example, in the patterning method of the quantum dot film layer provided in at least one embodiment of the present disclosure, the polarity of the quantum dot ligand is greater than the polarity of the photosensitizer, and the formation of the patterned quantum dot film layer includes: using a polar negative developer to remove the quantum dot film in the area other than the illuminated area to obtain the patterned quantum dot film layer; or using a non-polar positive developer to remove the quantum dot film in the illuminated area to obtain the patterned quantum dot film layer.

[0029] At least one embodiment of the present disclosure further provides a quantum dot display device, which includes a quantum dot film layer prepared from the quantum dot composition described in any of the above embodiments.

[0030] For example, in the quantum dot display device provided in at least one embodiment of the present disclosure, the quantum dot display device is a quantum dot light-emitting device, and the quantum dot light-emitting device includes a first electrode, a second electrode, and the quantum dot film layer sandwiched between the first electrode and the second electrode.

[0031] For example, in the quantum dot display device provided in at least one embodiment of the present disclosure, the quantum dot display device is a quantum dot color conversion device, and the quantum dot color conversion device includes a light-emitting substrate and the quantum dot film layer located on the light-emitting substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, rather than limiting the present disclosure.

[0033] FIG1 is a flow chart of a method for patterning a quantum dot film layer according to at least one embodiment of the present disclosure;

[0034] FIG2 is a process diagram of a patterning method of a quantum dot film layer according to at least one embodiment of the present disclosure;

[0035] FIG3 is a fluorescence microscope image of a quantum dot film layer formed by the patterning method of a quantum dot film layer provided in Example 4 of the present disclosure;

[0036] FIG4 is a fluorescence microscope image of a quantum dot film layer formed by the patterning method of the quantum dot film layer provided in the comparative example of Example 4;

[0037] FIG5 is a diagram illustrating a process of forming a full-color pattern according to at least one embodiment of the present disclosure;

[0038] FIG6 is a diagram illustrating another process of forming a full-color pattern according to at least one embodiment of the present disclosure;

[0039] FIG7 is a diagram illustrating another process of forming a full-color pattern according to at least one embodiment of the present disclosure;

[0040] FIG8 is a diagram illustrating another process of forming a full-color pattern according to at least one embodiment of the present disclosure;

[0041] FIG9 is a schematic cross-sectional view of a quantum dot display device according to at least one embodiment of the present disclosure;

[0042] FIG10 is a schematic cross-sectional view of another quantum dot display device provided by at least one embodiment of the present disclosure; and

[0043] FIG11 is a schematic diagram of the cross-sectional structure of another quantum dot display device provided in at least one embodiment of the present disclosure. DETAILED DESCRIPTION

[0044] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0045] Unless otherwise defined, technical or scientific terms used in this disclosure should have the ordinary meanings understood by people with ordinary skills in the field to which this disclosure belongs. The words "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are simply used to distinguish different components. The words "include" or "comprising" and similar terms mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0046] The confinement effect of quantum dot materials gives them the ability to regulate energy levels according to their size and morphology, and they have the properties of broadband absorption and narrowband emission. Quantum dot materials usually exist in the form of solutions, and quantum dot solutions can be directly processed, thus avoiding the use of expensive vacuum equipment, making quantum dot materials have large-scale potential applications in display, lighting, solar cells, and photoelectric detection. Patterning is the only way to pixelate quantum dot materials in solution and turn quantum dot materials into shaped optoelectronic devices and even commercial products. The indirect method using traditional photoresist can achieve quantum dot patterning, but due to the incompatibility between quantum dot solvents and photoresist solvents, and the introduction of photoresist usually reduces the luminescence properties of the quantum dots themselves, it is difficult to achieve quantum dot patterning using traditional photoresist processes.

[0047] The surface of the quantum dot body usually has ligands, which are photoresponsive, giving the quantum dot material the ability to be directly patterned by photolithography. The main principle of photolithography patterning is to use the photosensitive groups in the photosensitizer and the ligands on the surface of the quantum dot to undergo a photochemical reaction to change the chemical properties of the surface of the quantum dot body, thereby changing the solubility and colloidal stability of the quantum dot. The quantum dot body coated with surface ligand molecules of different polarities can be dissolved in solvents with corresponding polarities, but cannot be dissolved in other solvents with greatly different polarities. Therefore, from the perspective of changing the polarity of the molecules, introducing photochemical reaction design is an effective way to achieve quantum dot film patterning. Dimitri et al. have developed a variety of quantum dot inks with inorganic ligands coated on the surface and easily soluble in polar solvents. The surface ligand molecules in the quantum dot ink will undergo a decomposition reaction after exposure to light, so that the quantum dots will no longer dissolve in the original solvent, thereby achieving the effect of developing and leaving a film. However, quantum dots typically have organic ligands on their surfaces. To obtain quantum dot materials coated with inorganic photosensitive ligands, the quantum dots must undergo a ligand exchange process, which carries the risk of weakening the photoelectric properties of the quantum dots. Therefore, utilizing the existing ligands on the quantum dot surface without the need for a ligand exchange process and introducing a novel photochemical reaction system to alter the polarity of the quantum dot surface ligands has significant development potential.

[0048] The inventors of the present disclosure have noticed that the polarity of the surface ligands of quantum dots changes after irradiation, so that the quantum dot material no longer dissolves in the original good solvent, thereby achieving the effect of photolithographic patterning of quantum dots. The photolithographic patterning method includes the following steps: a mixed solution of quantum dot material and a photosensitizer having both photoresponsiveness and polarity-changing groups is formed into a thin film on the main surface of a substrate by scraping, spin coating, spraying, etc., and a photomask is used to cause a photochemical reaction in the illuminated area of ​​the film under exposure conditions, so that the surface ligands of the quantum dot body in the illuminated area are different from the surface ligands of the quantum dot body in the non-illuminated area. The difference in properties includes the difference between polarity and non-polarity, and the difference between strong polarity and weak polarity. The difference in properties is sufficient to cause the solubility of the quantum dot material in the illuminated area in the original good solvent to change. Finally, the quantum dot material in the illuminated area or the non-illuminated area is removed by elution and development using a solvent with a specific polarity, thereby obtaining a positively patterned or negatively patterned quantum dot film layer accordingly. The process of implementing this method is simple. It directly performs photolithographic patterning by utilizing the characteristics of the surface chemical property changes of the quantum dots, avoiding the destruction of the photoelectric properties of the quantum dots by the introduction of photoresist. In addition, the subsequent development method is flexible. By selecting solvents with different polarities for development, a quantum dot film layer with a positive pattern or a negative pattern can be obtained.

[0049] Embodiments of the present disclosure relate to a quantum dot composition, a method for patterning a quantum dot film layer, and a quantum dot display device. The quantum dot composition includes: a mixed quantum dot material and a photosensitizer, the quantum dot material includes a quantum dot body and a first quantum dot ligand on the surface of the quantum dot body, the photosensitizer is configured to react with the first quantum dot ligand under light to form a second quantum dot ligand, the molecular weight of the second quantum dot ligand is greater than the molecular weight of the first quantum dot ligand, and the second quantum dot ligand and the first quantum dot ligand have different polarities. The embodiments of the present disclosure utilize the property that the polarity of the original ligand of the quantum dot changes after being connected to a specific group in the photosensitizer to achieve the purpose of photolithographic patterning of the quantum dot film layer.

[0050] At least one embodiment of the present disclosure provides a quantum dot composition, comprising: a mixed quantum dot material and a photosensitizer, wherein the quantum dot material comprises a quantum dot body and a first quantum dot ligand on the surface of the quantum dot body; the photosensitizer is configured to react with the first quantum dot ligand under illumination to form a second quantum dot ligand, the second quantum dot ligand having a molecular weight greater than that of the first quantum dot ligand, and the second quantum dot ligand and the first quantum dot ligand having different polarities. In the embodiments of the present disclosure, the key to selecting the photosensitizer is that the photosensitizer is composed of a photosensitizer group and a polarity-changing group. Before illumination, the photosensitizer can form a mixed solution with the quantum dots. After forming a quantum dot film and irradiating the film, the photosensitizer group reacts with the ligand on the surface of the quantum dot body, causing the polarity-changing group to be grafted onto the surface ligand of the quantum dot body to achieve the purpose and effect of changing the polarity of the surface ligand of the quantum dot body.

[0051] It should be noted that the "polarity" in the phrase "the second quantum dot ligand and the first quantum dot ligand have different polarities" does not necessarily mean that both the second quantum dot ligand and the first quantum dot ligand have polarity. Polarity here simply represents a property of the second quantum dot ligand and the first quantum dot ligand. Alternatively, the first quantum dot ligand may have weak polarity and the second quantum dot ligand may have strong polarity. Alternatively, the first quantum dot ligand may have strong polarity and the second quantum dot ligand may have weak polarity. Alternatively, the first quantum dot ligand may have strong polarity and the second quantum dot ligand may have strong polarity. Alternatively, the first quantum dot ligand may have strong polarity and the second quantum dot ligand may have no polarity, that is, the second quantum dot ligand may be non-polar. The embodiments of the present disclosure do not limit this.

[0052] For example, in one example, the polarity index of the second quantum dot ligand is greater than or equal to 0 and less than 3.6, and correspondingly, the polarity index of the first quantum dot ligand is greater than 3.6 and less than 13. Alternatively, in another example, the polarity index of the first quantum dot ligand is greater than or equal to 0 and less than 3.6, and correspondingly, the polarity index of the second quantum dot ligand is greater than 3.6 and less than 13. For example, the difference between the polarity index of the second quantum dot ligand and the polarity index of the first quantum dot ligand is at least greater than 3.6.

[0053] For example, the mixed quantum dot material and photosensitizer may be uniformly mixed or non-uniformly mixed, and the embodiments disclosed herein do not impose any specific limitation on the degree of uniformity of the mixing.

[0054] For example, different photosensitizers can be added to different quantum dot bodies according to the type of ligands on their surfaces. The ligands on the surface of the quantum dot body include oxygen-coordinated ligands, nitrogen-coordinated ligands, phosphine-coordinated ligands, or sulfur-coordinated ligands. For example, oxygen-coordinated ligands include carboxyl groups, nitrogen-coordinated ligands include amino groups, phosphine-coordinated ligands include phosphino groups, and sulfur-coordinated ligands include sulfhydryl groups. For example, carboxylate ligands on the surface of the quantum dot body include oleic acid, amino ligands include oleylamine, phosphino ligands include trioctylphosphine, and sulfhydryl ligands include dodecanethiol. Photosensitizers include photoacid generators, olefins, or alkynes. When the ligands on the surface of the quantum dot body are carboxylate ligands, the corresponding photosensitizers can be: diazonaphthoquinones, triazines, trifluorosulfonates, etc. When the ligands on the surface of the quantum dot body are sulfhydryl ligands, the doped photosensitive materials can be: olefins, alkynes, etc. Of course, the photosensitizer is not limited to photoacid generators, olefinic substances or alkyne substances, and the corresponding photosensitizer can be selected according to the type of ligand on the surface of the quantum dot body.

[0055] For example, compared to conventional quantum dot compositions, the advantages of the quantum dot compositions in the embodiments of the present disclosure are: utilizing the original ligands of the quantum dot body, eliminating the need for ligand exchange, reducing the number of processing steps, and preserving the original properties of the quantum dots as much as possible. There is no need for a photoresist process, the principle of this solution is simple, and the quantum dot composition consists only of quantum dots and photosensitizers, so this method is universal. Photosensitizers can pattern quantum dots and ligands with different component structures. Depending on the change in polarity, it can be designed as a positive photoresist composition, that is, the quantum dot material in the illuminated area is developed; it can also be designed as a negative photoresist composition, that is, the quantum dot material in the non-illuminated area is developed.

[0056] For example, a quantum dot layer having different colors formed by different quantum dot compositions includes quantum dot bodies that emit light of different colors, and the quantum dot bodies that emit light of different colors can be semiconductor nanocrystals and can have a variety of shapes, for example, spherical, conical, multi-armed and / or cubic nanoparticles, nanotubes, nanowires, nanofibers, nanoplate particles, quantum rods, or quantum sheets. For example, the quantum rod can be a quantum dot having an aspect ratio (length to diameter ratio) (length: width ratio) greater than about 1, for example, greater than or equal to about 2, greater than or equal to about 3, or greater than or equal to about 5. For example, the quantum rod can have an aspect ratio of less than or equal to about 50, less than or equal to about 30, or less than or equal to about 20.

[0057] For example, in one example, the quantum dot body can have a particle diameter (average maximum particle length for non-spherical shapes) of, for example, about 1 nm to about 100 nm, about 1 nm to about 80 nm, about 1 nm to about 50 nm, or about 1 nm to 20 nm.

[0058] For example, the energy band gap of the quantum dot body can be controlled according to the size and composition of the quantum dot body, and thus the emission wavelength can be controlled. For example, when the size of the quantum dot body increases, the quantum dot body can have a narrow energy band gap and can emit light in a relatively long wavelength region, and when the size of the quantum dot body decreases, the quantum dot body can have a wide energy band gap and can therefore emit light in a relatively short wavelength region. For example, the quantum dot body can be configured to emit light in a predetermined wavelength region in the visible light region according to its size and / or composition. For example, the quantum dot body can emit blue light, red light or green light, and the blue light can have a peak emission wavelength (λ maximum), for example, in the range of about 430 nm to about 480 nm, the red light can have a peak emission wavelength (λ maximum), for example, in the range of about 600 nm to about 650 nm, and the green light can have a peak emission wavelength (λ maximum), for example, in the range of about 520 nm to about 560 nm.

[0059] For example, the average particle size of the quantum dot body that can emit blue light is, for example, less than or equal to about 4.5 nm, such as less than or equal to about 4.3 nm, less than or equal to about 4.2 nm, less than or equal to about 4.1 nm, or less than or equal to about 4.0 nm. Within the above range, for example, the average particle size of the quantum dot body can be about 2.0 nm to about 4.5 nm, such as about 2.0 nm to about 4.3 nm, about 2.0 nm to about 4.2 nm, about 2.0 nm to about 4.1 nm, or about 2.0 nm to about 4.0 nm.

[0060] For example, the quantum dot body can have a relatively narrow full width at half maximum (FWHM), which is the width corresponding to half the wavelength of the peak absorption point. When the FWHM is narrow, it can be configured to emit light in a narrow wavelength region and obtain higher color purity. The quantum dot body can have a FWHM of, for example, less than or equal to about 50 nm. Within the above range, it can have a FWHM of, for example, about 2 nm to about 49 nm.

[0061] For example, the material of the quantum dot body may include a II-VI semiconductor compound, a III-V semiconductor compound, a IV-VI semiconductor compound, a I-III-VI semiconductor compound, a I-II-IV-VI semiconductor compound, a II-III-V semiconductor compound, or a combination thereof. The II-VI semiconductor compound is, for example, selected from a binary compound such as CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, or a mixture of MgS; a ternary compound such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, or a mixture thereof. For example, in another example, Hg x Cd (1-x) Te, Hg x Cd (1-x) S, Hg x Cd (1-x) Se, Hg x Zn (1-x) Te, Cd x Zn (1-x) Se or Cd x Zn (1-x)S, where 0 < x < 1; and quaternary compounds such as HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or mixtures of the above compounds, but the embodiments of the present disclosure are not limited thereto. The III-V semiconductor compounds may be selected from: binary compounds such as mixtures of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb; ternary compounds such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb or mixtures of the above compounds; and quaternary compounds such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb or mixtures of the above compounds, but the embodiments of the present disclosure are not limited thereto. The IV-VI semiconductor compounds may be selected, for example, from: binary compounds such as mixtures of SnS, SnSe, SnTe, PbS, PbSe, PbTe; ternary compounds such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe or mixtures of the above compounds; and quaternary compounds such as SnPbSSe, SnPbSeTe, SnPbSTe or mixtures of the above compounds, but the embodiments of the present disclosure are not limited thereto. The I-III-VI semiconductor compounds may be, for example, CuInSe2, CuInS2, CuInGaSe, CuInGaS or mixtures of the above compounds, but the embodiments of the present disclosure are not limited thereto. The I-II-IV-VI semiconductor compounds may be, for example, CuZnSnSe, CuZnSnS or mixtures of the above compounds, but the embodiments of the present disclosure are not limited thereto. The II-III-V semiconductor compounds may include, for example, InZnP, but the embodiments of the present disclosure are not limited thereto.

[0062] For example, the quantum dot body may have a substantially uniform concentration distribution or a locally different concentration distribution, and the quantum dot body includes a mixture of the above binary semiconductor compounds, the above ternary semiconductor compounds, or the above quaternary semiconductor compounds.

[0063] For example, as an embodiment, the quantum dot body can be a Zn-Te-Se semiconductor compound. For example, the amount of tellurium (Te) in the Zn-Te-Se semiconductor compound can be less than the amount of selenium (Se). The semiconductor compound can have a peak emission wavelength (λ max) in a wavelength range of less than or equal to about 480 nm, such as about 430 nm to about 480 nm, and can be configured to emit blue light.

[0064] For example, the quantum dot body may include an In-Zn-P semiconductor compound. For example, in the In-Zn-P semiconductor compound, the molar ratio of zinc (Zn) to indium (In) may be greater than or equal to about 25. The semiconductor compound may have a peak emission wavelength (λ max ) in a wavelength region less than about 700 nm, for example, about 600 nm to about 650 nm, and may be configured to emit red light.

[0065] For example, the quantum dot body can have a core-shell structure, i.e., a nanoparticle formed by a layer of quantum dot material surrounding another quantum dot material. For example, the core and shell of the quantum dot body can have an interface, and at least one element of the core or shell at the interface can have a concentration gradient, with the concentration of the shell element gradually decreasing toward the core. For example, the material composition of the shell of the quantum dot body has a higher band gap than the material composition of the core of the quantum dot, and thus the quantum dot can exhibit a quantum confinement effect.

[0066] For example, the quantum dot body may have a quantum dot core and a multi-layer quantum dot shell surrounding the core. The multi-layer shell refers to a structure having at least two shells, wherein each shell may be a single composition, an alloy, and / or a structure having a concentration gradient.

[0067] For example, the shells of the multi-layer shells that are farther from the core have a higher band gap than the shells that are closer to the core, and thus the quantum dot body can exhibit a quantum confinement effect.

[0068] For example, a quantum dot body having a core-shell structure may, for example, include a core comprising a first semiconductor compound, the first semiconductor compound comprising zinc (Zn), and at least one of tellurium (Te) and selenium (Se); and a shell comprising a second semiconductor compound disposed on at least a portion of the core and having a composition different from the composition of the core.

[0069] For example, the first semiconductor compound may be a Zn-Te-Se based semiconductor compound including zinc (Zn), tellurium (Te), and selenium (Se), for example, a Zn-Se based semiconductor compound including a small amount of tellurium (Te), for example, a ZnTexSe based semiconductor compound. (1-x) A semiconductor compound represented by , wherein x is greater than 0 and less than or equal to 0.05.

[0070] For example, in a first semiconductor compound based on Zn-Te-Se, the molar amount of zinc (Zn) may be higher than the molar amount of selenium (Se), and the molar amount of selenium (Se) may be higher than the molar amount of tellurium (Te). For example, in the first semiconductor compound, the molar ratio of tellurium (Te) to selenium (Se) may be less than or equal to about 0.05. For example, in the first semiconductor compound, the molar ratio of tellurium (Te) to zinc (Zn) may be less than or equal to about 0.02.

[0071] For example, the second semiconductor compound may include, for example, a II-VI semiconductor compound, a III-V semiconductor compound, a IV-VI semiconductor compound, a Group IV semiconductor, a I-III-VI semiconductor compound, a I-II-IV-VI semiconductor compound, a II-III-V semiconductor compound, or a combination thereof. Embodiments of the II-VI semiconductor compound, the III-V semiconductor compound, the IV-VI semiconductor compound, the IV semiconductor, the I-III-VI semiconductor compound, the I-II-IV-VI semiconductor compound, and the II-III-V semiconductor compound are the same as described above.

[0072] For example, the second semiconductor compound may include zinc (Zn), selenium (Se), and / or sulfur (S). For example, the shell may include ZnSeS, ZnSe, ZnS, or a combination thereof. For example, the shell may include at least one inner shell disposed proximate to the core and an outermost shell disposed at the outermost side of the quantum dot. The inner shell may include ZnSeS, ZnSe, or a combination of the foregoing compounds, and the outermost shell may include ZnS. For example, the shell may have a concentration gradient of a component, and, for example, the amount of sulfur (S) may increase with increasing distance from the core.

[0073] For example, a core of a quantum dot having a core-shell structure includes a third semiconductor compound, which includes at least one of indium (In), zinc (Zn) and phosphorus (P); and a shell disposed on at least a portion of the core and including a fourth semiconductor compound having a composition different from that of the core.

[0074] For example, in the third semiconductor compound based on In-Zn-P, the molar ratio of zinc (Zn) to indium (In) may be greater than or equal to about 25. For example, in the third semiconductor compound based on In-Zn-P, the molar ratio of zinc (Zn) to indium (In) may be greater than or equal to about 28, greater than or equal to about 29, or greater than or equal to about 30. For example, in the third semiconductor compound based on In-Zn-P, the molar ratio of zinc (Zn) to indium (In) may be less than or equal to about 55, for example, less than or equal to about 50, less than or equal to about 45, less than or equal to about 40, less than or equal to about 35, less than or equal to about 34, less than or equal to about 33, or less than or equal to about 32.

[0075] For example, the fourth semiconductor compound may include, for example, a II-VI semiconductor compound, a III-V semiconductor compound, a IV-VI semiconductor compound, a Group IV semiconductor, a I-III-VI semiconductor compound, a I-II-IV-VI semiconductor compound, a II-III-V semiconductor compound, or a combination thereof. Embodiments of the II-VI semiconductor compound, the III-V semiconductor compound, the IV-VI semiconductor compound, the IV semiconductor, the I-III-VI semiconductor compound, the I-II-IV-VI semiconductor compound, and the II-III-V semiconductor compound may be the same as described above.

[0076] For example, the fourth semiconductor compound may include zinc (Zn), sulfur (S), or selenium (Se). For example, the shell may include ZnSeS, ZnSe, ZnS, or a combination thereof. For example, the shell may include at least one inner shell disposed near the core and a shell disposed at the outermost side of the quantum dot. At least one of the inner shell and the outermost shell may include the fourth semiconductor compound ZnS, ZnSe, or ZnSeS.

[0077] For example, the quantum dot body can have a relatively deep HOMO energy level, for example, a HOMO energy level of greater than or equal to about 5.4 eV, within this range, for example, greater than or equal to about 5.5 eV, for example, greater than or equal to about 5.6 eV, for example, greater than or equal to about 5.7 eV, for example, greater than or equal to about 5.8 eV, for example, greater than or equal to about 5.9 eV, for example, greater than or equal to about 6.0 eV. Within this range, the HOMO energy level of the quantum dot layer can be, for example, from about 5.4 eV to about 7.0 eV.

[0078] For example, the quantum dot body can have a relatively shallow LUMO energy level, for example, less than or equal to about 3.7 eV, within this range, for example, less than or equal to about 3.6 eV, for example, less than or equal to about 3.5 eV, for example, less than or equal to about 3.4 eV, for example, less than or equal to about 3.3 eV, for example, less than or equal to about 3.2 eV, for example, less than or equal to about 3.0 eV. Within this range, the LUMO energy level of the quantum dot layer can be about 2.5 eV to about 3.7 eV, about 2.5 eV to about 3.6 eV, about 2.5 eV to about 3.5 eV, about 2.5 eV to about 3.4 eV, about 2.5 eV to about 3.3 eV, about 2.5 eV to about 3.2 eV, about 2.5 eV to about 3.1 eV, about 2.5 eV to about 3.0 eV, about 2.8 eV V to about 3.7 eV, about 2.8 eV to about 3.6 eV, about 2.8 eV to about 3.5 eV, about 2.8 eV to about 3.4 eV, about 2.8 eV to about 3.3 eV, about 2.8 eV to about 3.2 eV, about 3.0 eV to about 3.7 eV, about 3.0 eV to about 3.6 eV, about 3.0 eV to about 3.5 eV, or about 3.0 eV to about 3.4 eV.

[0079] For example, the quantum dot body can have an energy band gap of about 1.7 eV to about 2.3 eV or about 2.4 eV to about 2.9 eV. Within this range, for example, the quantum dot layer 13 can have an energy band gap of about 1.8 eV to about 2.2 eV or about 2.4 eV to about 2.8 eV, within this range, for example, about 1.9 eV to about 2.1 eV, for example, about 2.4 eV to about 2.7 eV.

[0080] For example, in one embodiment, the material of the quantum dot body includes a quantum dot body having a core-shell structure, wherein the core and shell of the core-shell structure are composed of Group IIB-VIA semiconductor compounds, respectively. The materials of the core and shell can be binary compounds, ternary compounds, or quaternary compounds, respectively. For example, the materials of the core and shell of the quantum dot can be CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, and HgTe, respectively.

[0081] For example, the quantum dot body with a core-shell structure includes CdSe@ZnS, CdSe@CdS, InP@ZnS, CdTe@CdSe, CdSe@ZnTeZnTe@CdSe, ZnSe@CdS or Cd1-xZnxS@ZnS. The quantum dot body can also be an ABX3 type perovskite quantum dot body or nanocrystal, where A is CH3NH3 + (methylamine), NH2CH=NH2(formamidine) and Cs + One or more of, B is Pb 2+ and Sn 2+One or two of the following, X is Cl - Br - and I - One or more of the following. For example, the ABX3 type perovskite quantum dot body includes at least one of CH3NH3PbBr3, CH3NH3PbCl3, CH3NH3PbI3, CsPbBr3, CsPbCl3, and CsPbI3. For example, other quantum dot bodies may also be used, such as CuInS2, CuInSe2, AgInS2, etc., as long as the quantum dot body is coated with an organic ligand on the surface.

[0082] For example, the material of the quantum dot body includes at least two metals, and the material of the quantum dot body is at least one of CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe and HgZnSTe. Usually, when the quantum dot body is excited by a blue light source, it will emit excitation fluorescence of a specific wavelength, and the fluorescence spectrum emitted is determined by the chemical composition and particle size of the quantum dot material. As the particle size of the quantum dot body material increases, the fluorescence spectrum emitted by the material with the same chemical composition is red-shifted from green light to red light. The quantum dot bulk material emitting red light and the quantum dot bulk material emitting green light can be quantum dot bulk materials with the same chemical composition but different particle sizes, or can be quantum dot bulk materials with different chemical compositions, that is, the quantum dot bulks in adjacent sub-pixel areas can be prepared from the same material but have different particle sizes, or the quantum dot bulks in adjacent sub-pixel areas can be prepared from different materials.

[0083] For example, the quantum dot body is a nanoscale semiconductor. By applying a certain electric field or light pressure to the nanoscale semiconductor material, the nanoscale semiconductor material will emit light of a specific frequency, and the frequency of the emitted light will change with the change of the size of the semiconductor. Therefore, by adjusting the size of the quantum dot body, the color of the light it emits can be controlled.

[0084] For example, by controlling the shape, structure, and size of the quantum dot body, the energy gap width, exciton binding energy, and electronic states such as the exciton energy blue shift of the quantum dot body can be easily adjusted. As the size of the quantum dot body decreases, the spectrum of the quantum dot body blue shifts. The smaller the size of the quantum dot body, the more significant the blue shift phenomenon. For example, for the cadmium selenide quantum dot body, when it is reduced from 10nm to 2nm, the color of the light emitted by the cadmium selenide quantum dot body changes from red to blue. When the size of the cadmium selenide quantum dot body is greater than or equal to 2nm and less than 5nm, blue light is emitted; when the size of the cadmium selenide quantum dot body is greater than or equal to 5nm and less than 8nm, green light is emitted; when the size of the cadmium selenide quantum dot body is greater than or equal to 8nm and less than 10nm, red light is emitted.

[0085] For example, the unique properties of quantum dots are based on their inherent quantum size effects. When the particle size of quantum dots reaches the nanometer scale, size confinement will induce size effects, quantum confinement effects, macroscopic quantum tunneling effects, and surface effects, thereby deriving low-dimensional physical properties that differ from those of microscopic systems, and endowing quantum dots with physical and chemical properties that differ from those of microscopic systems. For example, quantum dots possess unique photoluminescence and electroluminescence properties due to quantum size effects and electrical confinement effects. Compared with organic fluorescent dyes, quantum dot materials have excellent optical properties such as high quantum yield, high photochemical stability, and resistance to photolysis, as well as broad excitation, narrow emission, high color purity, and luminescence color that can be adjusted by controlling the size of the quantum dot. As a result, quantum dot light-emitting devices including quantum dot light-emitting layers have advantages such as high luminous efficiency, good stability, long life, high brightness, and a wide color gamut.

[0086] For example, in the quantum dot composition provided in at least one embodiment of the present disclosure, the first quantum dot ligand is mainly composed of three parts, with the general formula DEF, wherein D is an anchor group capable of being grafted to the surface of the quantum dot; E is a linking group, for example, an alkyl group or a polyether segment (such as an oligomer polyethylene oxide, etc.), or E is an alkyl group with one or more double bonds or benzene ring groups; and F is a functional group. For example, the first quantum dot ligand includes a ligand group D that is bound to the surface of the quantum dot body, a first linking group E connected to the ligand group D, and a first functional group F connected to the first linking group E. The first linking group E can serve to connect the first functional group F and the first linking group E.

[0087] For example, in one example, the coordination group D can be one or more of a thiol (-SH), a carboxyl (-COOH), an amino (-NH2), a phosphino (-P-) and a phosphinooxy (-P=O). The first linking group E is at least one of a C1-C30 straight-chain alkyl group or an unsaturated hydrocarbon chain and a polyether segment compound having one or more double bonds or benzene rings. For example, the first linking group E is an alkyl chain containing less than 10 carbon atoms and may contain one or more double bonds or phenyl groups. The first functional group F can be at least one of a methyl group, a phenyl group, a sulfonic acid group, a carboxyl group, a nitroso group, a cyano group, a hydroxyl group, an amide group, a phenolic hydroxyl group, a thiol group, an amino group, an aldehyde group, a carbonyl group, an alkenyl group, an alkynyl group, an ether bond and a thioether bond. The corresponding first quantum dot ligands are oleic acid, oleylamine, mercaptopropionic acid, mercaptoethanol, 1-dodecylmercaptan, 1-octanethiol, 6-mercaptohexanol, stearic acid, ethylenediamine, ethanedithiol, thiophenol and benzenedithiophenol (including ortho- and meta-pairs), etc.

[0088] For example, when the first functional group F is a strongly polar group, it can be selected from at least one of a sulfonic acid group, a carboxyl group, a nitroso group, a cyano group, a hydroxyl group, an amide group, a phenolic hydroxyl group, a thiol group, and an amino group.

[0089] For example, when the first functional group F is a weak polar group, it can be selected as a methyl group, a phenyl group, an aldehyde group, etc., and the first functional group F can contain one or more other weak polar intermediate groups, for example, at least one of a carbonyl group, an alkenyl group, an alkynyl group, an ether bond, and a thioether bond.

[0090] For example, in another embodiment, the first quantum dot ligand can also be mainly composed of two parts, with the general formula DE, wherein D is an anchor group that can be grafted to the surface of the quantum dot; E is a linking group, for example, an alkyl group or a polyether segment (such as an oligomer polyethylene oxide, etc.), or E is an alkyl group and has one or more double bonds or benzene ring groups, that is, the first quantum dot ligand may not have a functional group. For example, the first quantum dot ligand includes a ligand group D that is bound to the surface of the quantum dot body and a first linking group E connected to the ligand group D. The selection of the ligand group D and the first linking group E can refer to the relevant description above and will not be repeated here.

[0091] For example, in a quantum dot composition, the polarity of the quantum dot is determined by the polarity of the first quantum dot ligand attached to the quantum dot body. The greater the number of ligand groups D in the first quantum dot ligand, the stronger the binding force between the first quantum dot ligand and the quantum dot body. Fewer carbon atoms in the first linking group E enhance the polarity of the first quantum dot ligand, while more carbon atoms enhance the non-polarity of the first quantum dot ligand.

[0092] For example, in one embodiment, the photosensitizer is an organic substance that can undergo a photochemical reaction after being irradiated with light, and its general formula is, for example, ABC. The photosensitizer includes a photosensitizing group A, a second linking group B connected to the photosensitizing group A, and a second functional group C connected to the second linking group B. The first functional group F included in the above-mentioned first quantum dot ligand and the second functional group C included in the photosensitizer have different polarities, or the above-mentioned first quantum dot ligand does not include the first functional group, that is, the first quantum dot ligand is non-polar, and the second functional group C included in the photosensitizer has a strong polarity. For example, the above-mentioned photochemical reaction mainly includes a carbon-hydrogen insertion reaction and a carbon-carbon double bond addition reaction. Through the carbon-hydrogen insertion reaction or the carbon-carbon double bond addition reaction, the polarity of the first quantum dot ligand of the quantum dot changes after being connected to the second functional group C in the photosensitizer, thereby achieving the purpose of subsequent photolithographic patterning of the quantum dot film layer, and at the same time, the molecular weight of the second quantum dot ligand can be made greater than the molecular weight of the first quantum dot ligand.

[0093] For example, the more photosensitizer groups A the more photosensitizer there are, the higher the sensitivity of the photosensitizer, and the lower the light dose required to produce the quantum dot pattern. The fewer carbon atoms in the second linking group B, the more favorable it is for enhancing the polarity of the quantum dots after illumination, while the more carbon atoms, the more favorable it is for enhancing the non-polarity of the quantum dots after illumination. The more second functional groups C there are, the easier it is to change the polarity and solubility of the quantum dots after illumination.

[0094] For example, in the embodiments of the present disclosure, the above-mentioned carbon-hydrogen insertion reaction and carbon-carbon double bond addition reaction mainly occur on the first connecting group E, that is, when performing the above-mentioned carbon-hydrogen insertion reaction and carbon-carbon double bond addition reaction, there is no need to change the coordination group D included in the first quantum dot ligand, nor is there any need to adopt the method of peeling off the first quantum dot ligand to achieve a change in the solubility of the quantum dot. If the first quantum dot ligand falls off from the quantum dot body, it will lead to surface defects of the quantum dot body, thereby reducing the probability of exciton radiation recombination, which is not conducive to its application in display. The embodiments of the present disclosure can basically maintain the original environment of the first quantum dot ligand of the quantum dot body by changing some functional groups of the first quantum dot ligand, for example, changing the first linking group E so that the molecular weight of the second quantum dot ligand is greater than the molecular weight of the first quantum dot ligand, without reducing or cross-linking the ligand group D and the first linking group E. Therefore, the impact on the performance of the electroluminescent device finally formed is limited, that is, the ligand group D included in the first quantum dot ligand is not changed, thereby not affecting the interaction between the first quantum dot ligand and the quantum dot body, and not causing the first quantum dot ligand to fall off from the surface of the quantum dot body, thereby not introducing defects. After the photoresist composition is irradiated with light, the first quantum dot ligand can still effectively passivate surface defects, which is beneficial to the maintenance of the photoelectric properties of the quantum dots.

[0095] For example, in one example, the first quantum dot ligand includes a C-H bond, and the photosensitizer is configured to form at least one of a nitrogen carbene, a carbonyl radical, and a carbene under illumination, and the at least one of the nitrogen carbene, the carbonyl radical, and the carbene undergoes a carbon-hydrogen insertion reaction with the C-H bond included in the first quantum dot ligand to form the second quantum dot ligand. For example, the photosensitizer undergoes a carbon-hydrogen insertion reaction with the C-H bond included in the first quantum dot ligand under illumination to form the second quantum dot ligand, and causes the second functional group C included in the photosensitizer to replace the first functional group F in the first quantum dot ligand, or causes the second functional group C included in the photosensitizer to be formed on the first quantum dot ligand that does not have the first functional group, so that the second quantum dot ligand and the first quantum dot ligand have different polarities.

[0096] For example, carbene, also known as carbon bene or carbenes, is formed by the elimination of a neutral molecule from a molecule containing an easy-leaving group. Like carbon free radicals, it is a neutral, reactive intermediate with no positive or negative charge. Carbene is the general term for H2C: and its substituted derivatives. Carbene contains an electrically neutral, divalent carbon atom with two unbonded electrons, making it a highly reactive intermediate with two unbonded electrons.

[0097] For example, the higher the sensitivity of the photosensitizer, the lower the light dose required to obtain the quantum dot pattern. The greater the number of second functional groups C, the greater the change in the solubility of the quantum dots before and after light exposure.

[0098] For example, in one embodiment, the second quantum dot ligand includes a photosensitive group comprising at least one of azide, benzophenone, and diazirine. The photosensitive group enables the quantum dot composition to generate photosensitive intermediates, such as nitrogen carbene, carbonyl radical, carbene, etc., after ultraviolet light exposure.

[0099] For example, in one example, the quantum dot ligand includes a C=C bond, and the photosensitive group is configured to undergo an addition reaction with the C=C bond included in the first quantum dot ligand under light to form a second quantum dot ligand, so that the molecular weight of the second quantum dot ligand is greater than the molecular weight of the first quantum dot ligand.

[0100] For example, in one example, the photosensitizer forms a nitrogen carbene under light, and the nitrogen carbene undergoes an addition reaction with the C=C bond included in the first quantum dot ligand to form a second quantum dot ligand, and the second functional group C included in the photosensitizer replaces the first functional group F in the first quantum dot ligand, or the second functional group C included in the photosensitizer is formed on the first quantum dot ligand that does not have the first functional group, so that the second quantum dot ligand and the first quantum dot ligand have different polarities.

[0101] For example, in one example, the photosensitive group includes azide, so that under ultraviolet light, azide can undergo a carbon-carbon double bond addition reaction in addition to a carbon-hydrogen insertion reaction, that is, Thus, a photosensitive intermediate nitrogen carbene is generated. For example, the photosensitive group may include one or more azides.

[0102] For example, in one example, the second linking group includes a C1-C30 straight-chain alkyl group, or an unsaturated hydrocarbon chain having one or more double bonds or benzene rings. The second functional group includes at least one of a sulfonic acid, carboxyl, nitroso, cyano, hydroxyl, amide, phenolic hydroxyl, sulfhydryl, amino, methyl, aldehyde, alkyl, carbonyl, alkenyl, alkynyl, ether bond, and thioether bond. The second linking group B can serve to connect the second functional group C and the photosensitive group A.

[0103] For example, in one example, the second functional group is a strongly polar group, and correspondingly, the first functional group is a weakly polar group. For example, the second functional group is at least one of sulfonic acid, carboxyl, nitroso, cyano, hydroxyl, amide, phenolic hydroxyl, thiol, and amino, and the first functional group is at least one of methyl, aldehyde, carbonyl, alkenyl, alkynyl, ether bond, and thioether bond, but the embodiments of the present disclosure are not limited thereto, as long as the polarity of the second functional group is greater than the polarity of the first functional group.

[0104] For example, in another example, the second functional group is a weak polar group, and correspondingly, the first functional group is a strong polar group. For example, the second functional group is at least one of a methyl group, an aldehyde group, an alkyl group, a carbonyl group, an alkenyl group, an alkynyl group, an ether bond, and a thioether bond, and the first functional group is at least one of a phenyl group, a sulfonic acid group, a carboxyl group, a nitroso group, a cyano group, a hydroxyl group, an amide group, a phenolic hydroxyl group, a thiol group, and an amino group, but the embodiments of the present disclosure are not limited thereto, as long as the polarity of the second functional group is less than the polarity of the first functional group.

[0105] For example, the quantum dot composition provided in at least one embodiment of the present disclosure further includes a solvent, wherein the solvent is a weakly polar solvent or a non-polar solvent, and the first functional group is a weakly polar group or a non-polar group, so that the quantum dot material can be fully dissolved in the weakly polar solvent or the non-polar solvent before irradiation. The corresponding second functional group is a strongly polar group, so that the polarity of the second quantum dot ligand on the surface of the quantum dot after irradiation is different from the polarity of the first quantum dot ligand, and the dielectric constant of the weakly polar solvent or the non-polar solvent is less than 3.6.

[0106] For example, in one example, the weak polar solvent or non-polar solvent includes at least one of cyclohexane, petroleum ether, octane, trimethylpentane, carbon tetrachloride, trichlorotrifluoroethane, p-xylene, chlorobenzene, o-dichlorobenzene, ether, diethyl ether, tetrahydrofuran, hexane, pentane, toluene and chlorobenzene, but the embodiments of the present disclosure are not limited thereto and may also be other weak polar solvents or non-polar solvents.

[0107] For example, in one example, the first quantum dot ligand is 1-octanethiol or oleic acid, the corresponding photosensitizer is 2,3,4,5-tetrafluoro-4-azidobenzoic acid or 3-benzoylbenzoic acid, and the solvent is the weak polar solvent or the non-polar solvent.

[0108] For example, at least one embodiment of the present disclosure provides a quantum dot composition further comprising a solvent, wherein the solvent is a highly polar solvent, and the first functional group is highly polar, so that the quantum dot material can be fully dissolved in the highly polar solvent before irradiation. The corresponding second functional group is weakly polar or non-polar, and the dielectric constant of the highly polar solvent is greater than or equal to 3.6.

[0109] For example, in one example, the first quantum dot ligand is 6-mercaptohexanol, the corresponding photosensitizer is 2,3,4,5-tetrafluoro-4-azidooctadecylbenzene, and the solvent is a highly polar solvent.

[0110] For example, in one example, the highly polar solvent includes at least one of methanol, ethanol, isopropanol, ethyl acetate, acetonitrile, acetone, acetic acid, pyridine, N,N-dimethylformamide and dimethyl sulfoxide, but the embodiments of the present disclosure are not limited thereto and may also be other highly polar solvents.

[0111] At least one embodiment of the present disclosure also provides a method for patterning a quantum dot film layer, which includes: providing a substrate; applying the quantum dot composition of any of the above embodiments on the substrate to form a quantum dot film; using a mask to block the quantum dot film, and using light to irradiate a partial area of ​​the quantum dot film to increase the molecular weight of the quantum dot ligands in the partial area and change the polarity of the quantum dot ligands; using a developer to develop the quantum dot film to obtain a patterned quantum dot film layer. The patterning method of the quantum dot film layer provided by the embodiment of the present disclosure has a simple process, and uses the surface chemical properties of quantum dots for direct photolithographic patterning, avoiding the introduction of photoresist to damage the photoelectric properties of quantum dots, and the subsequent development method is flexible. By selecting solvents with different polarities for development, a quantum dot film with a positive pattern or a negative pattern can be obtained.

[0112] For example, FIG1 is a flow chart of a patterning method of a quantum dot film layer provided in at least one embodiment of the present disclosure. As shown in FIG1 , the patterning method of the quantum dot film layer includes the following steps.

[0113] Step S101: providing a substrate.

[0114] For example, the substrate includes a rigid substrate or a flexible substrate, and the material of the substrate may include glass, plastic or other materials, which is not limited in the embodiments of the present disclosure.

[0115] Step S102: applying a quantum dot composition on a substrate to form a quantum dot film.

[0116] For example, the quantum dot composition includes a mixed quantum dot material and a photosensitizer, wherein the quantum dot material includes a quantum dot body and a first quantum dot ligand on the surface of the quantum dot body, and the photosensitizer is configured to react with the first quantum dot ligand under light to form a second quantum dot ligand, wherein the molecular weight of the second quantum dot ligand is greater than that of the first quantum dot ligand, and the second quantum dot ligand and the first quantum dot ligand have different polarities. For example, the photosensitizer includes a photosensitizer group, a second linker group connected to the photosensitizer group, and a second functional group connected to the second linker group. Before light exposure, the photosensitizer can form a blended solution with the quantum dot material. After the coating film is exposed to light, the photosensitizer group reacts with the first quantum dot ligand, causing the photosensitizer group to be grafted onto the first quantum dot ligand to achieve the purpose and effect of changing the polarity of the ligand on the surface of the quantum dot.

[0117] For example, applying the quantum dot composition on the substrate includes blade coating, spin coating, or spray coating the quantum dot composition on the substrate to form a quantum dot film.

[0118] Step S103: using a mask to cover the quantum dot film, and irradiating a partial area of ​​the quantum dot film with light to increase the molecular weight of the quantum dot ligands in the partial area and change the polarity of the quantum dot ligands.

[0119] For example, the mask includes a light-transmitting region and a light-blocking region, wherein the light-transmitting region allows light to pass through and allows the transmitted light to illuminate a partial region of the quantum dot film. Using light to illuminate a partial region of the quantum dot film to increase the molecular weight of the ligands on the surface of the quantum dot body in the illuminated partial region and change the polarity of the ligands on the surface of the quantum dot body includes: using a mask to block the quantum dot film, and using ultraviolet light or infrared light to illuminate a partial region of the quantum dot film, so that the molecular weight of the ligands on the surface of the quantum dot body in the partial region illuminated by the ultraviolet light or infrared light is increased and a second quantum dot ligand is formed, that is, light transmitted from the light-transmitting region illuminates a partial region of the quantum dot film, so that the first quantum dot ligand and the photosensitizer included in the quantum dot material in the illuminated partial region react to form a second quantum dot ligand, the molecular weight of the second quantum dot ligand being greater than that of the first quantum dot ligand, and the polarity of the quantum dot ligand can be changed. That is, the embodiments of the present disclosure utilize the property that the polarity of the original ligand of the quantum dot changes after the specific group in the photosensitizer is connected to achieve the purpose of photolithographic patterning of the quantum dot film layer.

[0120] Step S104: developing the quantum dot film with a developer to obtain a patterned quantum dot film layer.

[0121] For example, FIG2 is a process diagram of a patterning method of a quantum dot film layer provided in at least one embodiment of the present disclosure. As shown in FIG2 , the patterning method of the quantum dot film layer includes the following process steps.

[0122] Process step 1: applying a quantum dot composition 102 on a substrate 101 to form a quantum dot film 103 .

[0123] For example, applying the quantum dot composition 102 on the substrate 101 includes blade coating, spin coating, or spray coating the quantum dot composition on the substrate 101 to form the quantum dot film 103 .

[0124] Process step two: Use a mask plate 104 to block the quantum dot film 103, and use ultraviolet light or infrared light to irradiate a partial area 103a of the quantum dot film 103 to increase the molecular weight of the ligand on the surface of the quantum dot body in the exposed partial area 103a and change the polarity of the ligand on the surface of the quantum dot body.

[0125] For example, the ligands on the surface of the quantum dot bodies in the exposed partial area 103a and the ligands on the surface of the quantum dot bodies in the unexposed area have different polarities, which in turn results in different solubility of the quantum materials in corresponding solvents. Specifically, irradiating the partial area 103a of the quantum dot film 103 with ultraviolet or infrared light can cause the first quantum dot ligands on the surface of the quantum dot bodies in the quantum dot composition 102 to react with the photosensitizer to form second quantum dot ligands. The second quantum dot ligands have a greater molecular weight than the first quantum dot ligands, and the second quantum dot ligands and the first quantum dot ligands have different polarities.

[0126] Process step three: using a developer to develop the quantum dot film 103 to obtain a patterned quantum dot film layer 105 .

[0127] For example, a negative developer can be used to develop the quantum dot film 103, or a positive developer can be used to develop the quantum dot film 103. For example, a negative developer can be used to remove the quantum dot film in areas other than the illuminated area to obtain a patterned quantum dot film layer 105. That is, a solvent with a polarity similar to that of the solvent in the quantum dot material before illumination is used as the developer. The quantum dot material in the non-illuminated area is washed away by the developer, while the quantum dot material in the illuminated area remains, thereby obtaining a negative pattern. Alternatively, a positive developer can be used to remove the quantum dot material in the illuminated area to obtain a patterned quantum dot film layer 105. That is, a specific solvent that can dissolve the quantum dot material in the illuminated area is selected as the developer. The quantum dot material in the illuminated area can be washed away, thereby obtaining a positive pattern.

[0128] For example, the above-mentioned process steps 1 to 3 are used to form a patterned quantum dot film layer 105 corresponding to the first color, and then the above-mentioned process steps 1 to 3 are repeated to form a patterned quantum dot film layer 105 corresponding to the second color and a patterned quantum dot film layer 105 corresponding to the third color, thereby forming a full-color pattern.

[0129] For example, in one example, the first functional group included in the first quantum dot ligand is a weak polar group or a non-polar group, and the corresponding second functional group of the photosensitizer is a strong polar group. In this way, the ligand on the surface of the quantum dot body changes from weak polarity or non-polarity to strong polarity. Before the first quantum dot ligand and the photosensitizer react, the polarity of the solvent of the quantum dot material is similar to the polarity of the first quantum dot ligand. The solvent of the quantum dot material before the reaction is called the original solvent, and other solvents with different polarity from the original solvent are new solvents. For example, the polarity of the original solvent is weak polarity or non-polarity, and the polarity of the new solvent is strong polarity. When a negative developer is used to form a negative pattern, the solvent in the developer can be the original solvent, that is, the polarity of the solvent in the developer is similar to the polarity of the first quantum dot ligand, both of which are weak polarity or non-polarity. When a positive developer is used to form a positive pattern, the solvent in the developer can be a new solvent, that is, the polarity of the solvent in the developer is different from the polarity of the first quantum dot ligand, the polarity of the first quantum dot ligand is weak polarity or non-polarity, and the polarity of the solvent in the developer is strong polarity.

[0130] For example, in another example, the first functional group included in the first quantum dot ligand is a strong polar group, and the corresponding second functional group of the photosensitizer is a weak polar group or a non-polar group. In this way, the ligand on the surface of the quantum dot body changes from strong polarity to weak polarity or non-polarity. Before the first quantum dot ligand and the photosensitizer react, the polarity of the solvent of the quantum dot material is similar to the polarity of the first quantum dot ligand. The solvent of the quantum dot material before the reaction is called the original solvent, and other solvents with different polarity from the original solvent are new solvents. For example, the polarity of the original solvent is strong polarity, and the polarity of the new solvent is weak polarity or non-polarity. When a negative developer is used to form a negative pattern, the solvent in the developer can be the original solvent, that is, the polarity of the solvent in the developer is similar to the polarity of the first quantum dot ligand, both of which are strong polarity. When a positive developer is used to form a positive pattern, the solvent in the developer can be a new solvent, that is, the polarity of the solvent in the developer is different from the polarity of the first quantum dot ligand. The polarity of the first quantum dot ligand is strong polarity, and the polarity of the solvent in the developer is weak polarity or non-polarity.

[0131] For example, in the patterning method of the quantum dot film layer provided in the embodiment of the present disclosure, the first quantum dot ligand and the photosensitizer on the surface of the quantum dot body are directly subjected to a carbon-hydrogen insertion reaction or a carbon-carbon double bond addition reaction under light, so that the polarity of the first quantum dot ligand changes after the second functional group in the photosensitizer is connected, thereby achieving the purpose of subsequent photolithographic patterning of the quantum dot film layer. At the same time, the molecular weight of the second quantum dot ligand can be made greater than that of the first quantum dot ligand, that is, no ligand exchange is required, the processing steps are reduced, and the properties of the first quantum dot ligand connected to the quantum dot body are retained as much as possible. In addition, no photoresist process is required. The principle and composition of the patterning method are relatively simple. The quantum dot composition consists only of quantum dots and photosensitizers. Moreover, the patterning method is universal. The photosensitizer can pattern quantum dot materials formed by quantum dot bodies and first quantum dot ligands with different component structures. In addition, according to the change in the polarity of the ligands on the surface of the quantum dot body before and after light irradiation, a positive quantum dot composition can be designed, that is, the quantum dots in the illuminated area are developed.

[0132] For example, in another embodiment of the present disclosure, the polarity of the quantum dot ligand is less than the polarity of the photosensitizer, and forming a patterned quantum dot film layer includes: using a non-polar negative developer to remove the quantum dot film in areas other than the illuminated area to obtain a patterned quantum dot film layer.

[0133] For example, in another embodiment of the present disclosure, the polarity of the quantum dot ligand is less than the polarity of the photosensitizer, and forming a patterned quantum dot film layer includes: using a polar positive developer to remove the quantum dot film in the illuminated area to obtain a patterned quantum dot film layer.

[0134] For example, in another embodiment of the present disclosure, the polarity of the quantum dot ligand is greater than the polarity of the photosensitizer, and forming a patterned quantum dot film layer includes: using a polar negative developer to remove the quantum dot film in areas other than the illuminated area to obtain a patterned quantum dot film layer.

[0135] For example, in another embodiment of the present disclosure, a non-polar positive developer is used to remove the quantum dot film in the illuminated area to obtain a patterned quantum dot film layer.

[0136] For example, in Example 1, before the quantum dot film is irradiated with ultraviolet or infrared light, the first quantum dot ligand on the surface of the quantum dot body has strong polarity, the photosensitizer is non-polar or weakly polar, and the developer is non-polar or weakly polar. A patterned quantum dot film layer is formed using positive photoresist patterning. For example, the quantum dot composition comprises a red quantum dot body CdSe / ZnS, the first quantum dot ligand on the surface of the red quantum dot body is the strongly polar ligand 6-mercaptohexanol, the photosensitizer is the weakly polar organic molecule 2,3,4,5-tetrafluoro-4-azidooctadecylbenzene, and the solvent is ethanol. The quantum dot composition is spin-coated on a substrate to form a quantum dot film, wherein the mass volume concentrations of the quantum dot material and the photosensitizer are 25 g / L and 0.5 g / L, respectively. A mask is used to block the quantum dot film, and ultraviolet light is irradiated to a portion of the quantum dot film, i.e., the portion is exposed to ultraviolet light for 20 seconds. Since many long alkyl chains are grafted onto the first quantum dot ligand 6-mercaptohexanol on the surface of the quantum dot body during the ultraviolet light exposure process to form the second quantum dot ligand, that is, the ligand on the surface of the quantum dot body in the illuminated area changes from a strong polar ligand to a weak polar ligand, the quantum dot material in the illuminated area is no longer soluble in the original alcohol solvent with strong polarity, but is soluble in non-polar solvents, such as toluene. Therefore, if toluene is used to develop the patterned quantum dot film layer, the quantum dot material in the illuminated area is washed away, leaving the quantum dot material in the non-illuminated area to achieve positive photoresist patterning.

[0137] For example, since 6-mercaptohexanol includes multiple carbon-hydrogen bonds, chemical reactions can occur at any carbon-hydrogen bond position on 6-mercaptohexanol, and various types of chemical reactions can occur depending on the position of the carbon-hydrogen insertion reaction. That is, the position of the reaction is not fixed, and the reaction product is not unique. For example, the chemical reaction formula corresponding to Example 1 is:

[0138] or

[0139] wait.

[0140] For example, in Example 2, before the quantum dot film is irradiated with ultraviolet light or infrared light, the first quantum dot ligand on the surface of the quantum dot body has strong polarity, the photosensitizer is non-polar or weakly polar, the developer is strongly polar, and a patterned quantum dot film layer is formed by negative photoresist patterning. For example, the composition of the quantum dot composition includes a red quantum dot body CdSe / ZnS, the first quantum dot ligand on the surface of the red quantum dot body is a strongly polar ligand 6-mercaptohexanol, the photosensitizer is a weakly polar organic molecule 2,3,4,5-tetrafluoro-4-azidooctadecylbenzene, and the solvent is ethanol. The above quantum dot composition is spin-coated on a substrate to form a quantum dot film, wherein the mass volume concentrations of the quantum dot material and the photosensitizer are 25g / L and 0.5g / L, respectively. A mask is used to block the quantum dot film, and ultraviolet light is used to irradiate a portion of the quantum dot film, that is, the portion is exposed to ultraviolet light for 20 seconds. During the ultraviolet light exposure process, many long alkyl chains are grafted onto the first quantum dot ligand 6-mercaptohexanol on the surface of the quantum dot body to form a second quantum dot ligand, that is, the ligand on the surface of the quantum dot body in the illuminated area changes from a strong polar ligand to a weak polar ligand. Therefore, the quantum dot material in the illuminated area is no longer soluble in the original alcohol solvent with strong polarity, but the quantum dot material in the non-illuminated area is still soluble in a strong polar solvent, such as ethanol. Therefore, if ethanol is used to develop the patterned quantum dot film layer, the quantum dot material in the non-illuminated area is washed away, leaving the quantum dot material in the illuminated area to achieve negative photoresist patterning.

[0141] For example, since 6-mercaptohexanol includes multiple carbon-hydrogen bonds, chemical reactions can occur at any carbon-hydrogen bond position on 6-mercaptohexanol, and various types of chemical reactions can occur depending on the position of the carbon-hydrogen insertion reaction. That is, the position of the reaction is not fixed, and the reaction product is not unique. For example, the chemical reaction formula corresponding to Example 2 is:

[0142] or

[0143] wait.

[0144] For example, in Example 3, before the quantum dot film is irradiated with ultraviolet light or infrared light, the first quantum dot ligand on the surface of the quantum dot body is non-polar or weakly polar, the photosensitizer has a strong polarity, and the developer has a strong polarity, and a patterned quantum dot film layer is formed by positive photoresist patterning. For example, the components of the quantum dot composition include a red quantum dot body CdSe / ZnS, the first quantum dot ligand on the surface of the red quantum dot body is a weakly polar ligand 1-octanethiol, the photosensitizer is a strongly polar organic molecule 2,3,4,5-tetrafluoro-4-azidobenzoic acid or 3-benzoylbenzoic acid, and the solvent is a non-polar solvent toluene. The above quantum dot composition is spin-coated on a substrate to form a quantum dot film, wherein the mass volume concentrations of the quantum dot material and the photosensitizer are 25g / L and 0.5g / L, respectively. A mask is used to block the quantum dot film, and ultraviolet light is used to irradiate a portion of the quantum dot film, that is, the portion is exposed to ultraviolet light for 20 seconds, and then immersed in acetone for development to obtain a positive pattern. Since the photosensitizer 2,3,4,5-tetrafluoro-4-azidobenzoic acid or 3-benzoylbenzoic acid is connected to the first quantum dot ligand 1-octanethiol on the surface of the quantum dot body to form a second quantum dot ligand during the ultraviolet light exposure process, and since the photosensitizer contains a strong polar group carboxyl, the polarity of the ligand on the surface of the quantum dot body becomes larger after ultraviolet light exposure and is soluble in polar solvents such as acetone. Therefore, the quantum dot material in the illuminated area after ultraviolet light irradiation can be removed by acetone development, and the illuminated area cannot retain the pattern of the quantum dot film layer. Before illumination, the first quantum dot ligand 1-octanethiol on the surface of the quantum dot body is a weak polar group and is insoluble in polar solvents such as acetone, the developer. Therefore, the quantum dot material in the non-illuminated area is retained, achieving a positive patterning effect.

[0145] For example, since 1-octanethiol includes multiple carbon-hydrogen bonds, chemical reactions can occur at any carbon-hydrogen bond position on 1-octanethiol, and various types of chemical reactions can occur depending on the position of the carbon-hydrogen insertion reaction. That is, the position of the reaction is not fixed, and the reaction product is not unique. For example, the chemical reaction formula corresponding to Example 3 is:

[0146] or

[0147] wait.

[0148] For example, in Example 4, before the quantum dot film is irradiated with ultraviolet light or infrared light, the first quantum dot ligand on the surface of the quantum dot body is non-polar or weakly polar, the photosensitizer has a strong polarity, the developer is non-polar or weakly polar, and a patterned quantum dot film layer is formed by negative photoresist patterning. For example, the components of the quantum dot composition include the red quantum dot body CdSe / ZnS, the first quantum dot ligand on the surface of the red quantum dot body is the non-polar ligand oleic acid, the photosensitizer is the strongly polar organic molecule 2,3,4,5-tetrafluoro-4-azidobenzoic acid, and the solvent is the non-polar solvent toluene. The above quantum dot composition is spin-coated on the substrate to form a quantum dot film, wherein the mass volume concentrations of the quantum dot material and the photosensitizer are 25g / L and 0.5g / L, respectively. The quantum dot film is shielded by a mask, and a portion of the quantum dot film is irradiated with ultraviolet light, that is, the portion is exposed to ultraviolet light for 20 seconds, and then immersed in toluene for development to obtain a negative pattern. For example, FIG3 is a fluorescence microscope image of a quantum dot film layer formed by the patterning method of the quantum dot film layer provided in Example 4 of the present disclosure. As can be seen from FIG3, the pattern of the red quantum dot film layer in the area irradiated by ultraviolet light is complete and clear, and the pixels in other areas not irradiated by ultraviolet light cannot emit red light. This shows that after the area irradiated by ultraviolet light is exposed, the photosensitizer decomposes through azide light to generate nitrogen carbene, and the nitrogen carbene undergoes a carbon-hydrogen insertion reaction with the surface ligand oleic acid of the quantum dot body and is connected to the surface of the quantum dot body, so that the surface of the quantum dot body is grafted with a carboxylic acid functional group, thereby changing the polarity of the surface ligand of the quantum dot body, that is, the non-polar alkyl chain included in the original oleic acid is changed to an alkyl chain connected to a carboxyl group. The large change in polarity makes the quantum dot material in the illuminated area no longer soluble in the original solvent toluene. Moreover, the thickness of the red pixel pattern obtained by the method in Example 4 was measured to be 18nm by a step profiler.

[0149] For example, since oleic acid includes multiple carbon-hydrogen bonds, chemical reactions can occur at any carbon-hydrogen bond position on the oleic acid. Depending on the position of the carbon-hydrogen insertion reaction, various types of chemical reactions can occur. That is, the reaction position is not fixed, and the reaction product is not unique. For example, the chemical reaction formula corresponding to Example 4 is:

[0150] wait.

[0151] For example, in the above-mentioned embodiment 4, since the photosensitizer 2,3,4,5-tetrafluoro-4-azidobenzoic acid is connected to the first quantum dot ligand oleic acid on the surface of the quantum dot body to form a second quantum dot ligand during the ultraviolet light exposure process, and since the photosensitizer contains a strong polar group carboxyl, the polarity of the ligand on the surface of the quantum dot body becomes larger after ultraviolet light exposure, that is, the ligand on the surface of the quantum dot body in the illuminated area changes from a weak polar ligand to a strong polar ligand. Therefore, the quantum dot material in the illuminated area is no longer soluble in the original non-polar solvent toluene, but the quantum dot material in the non-illuminated area is still soluble in the non-polar solvent, such as toluene. Therefore, if the patterned quantum dot film layer is developed with toluene, the quantum dot material in the non-illuminated area is washed away, leaving the quantum dot material in the illuminated area to achieve negative photoresist patterning.

[0152] For example, in the comparative example of Example 4, before the quantum dot film is irradiated with ultraviolet light or infrared light, the first quantum dot ligand on the surface of the quantum dot body is non-polar or weakly polar, the photosensitizer is weakly polar, and the developer is non-polar or weakly polar. This combination cannot achieve patterning of the quantum dot film to form a quantum dot film layer. For example, the components of the quantum dot composition include the red quantum dot body CdSe / ZnS, the first quantum dot ligand on the surface of the red quantum dot body is the non-polar ligand oleic acid, the photosensitizer is the weakly polar organic molecule 2,3,4,5-tetrafluoro-4-azidobenzaldehyde, and the solvent is the non-polar solvent toluene. The above quantum dot composition is spin-coated on the substrate to form a quantum dot film, wherein the mass volume concentrations of the quantum dot material and the photosensitizer are 25g / L and 0.5g / L, respectively. A mask is used to block the quantum dot film, and ultraviolet light is used to irradiate a portion of the quantum dot film, that is, the portion is exposed to ultraviolet light for 20 seconds and then developed by immersion in toluene. For example, Figure 4 is a fluorescence microscope image of a quantum dot film layer formed by the patterning method of the quantum dot film layer provided in the comparative example of Example 4. It can be seen from Figure 4 that no red pattern appears after development, because the photosensitizer is connected to the ligand oleic acid on the surface of the quantum dot body after ultraviolet light irradiation, but because the photosensitizer contains an aldehyde group and has a weak polarity, the polarity of the ligand on the surface of the quantum dot body does not change significantly before and after ultraviolet light irradiation. The quantum dot materials in the illuminated area and the non-illuminated area are still dissolved in the original non-polar solvent toluene, and are eventually developed out by toluene, and no pattern can be left in the illuminated area and the non-illuminated area.

[0153] For example, in the comparative example of the above-mentioned embodiment 4, since the photosensitizer 2,3,4,5-tetrafluoro-4-azidobenzaldehyde is connected to the first quantum dot ligand oleic acid on the surface of the quantum dot body to form a second quantum dot ligand during the ultraviolet light exposure process, and since the photosensitizer contains a weak polar group aldehyde group, the polarity of the ligand on the surface of the quantum dot body remains basically unchanged after ultraviolet light exposure, that is, the ligand on the surface of the quantum dot body in the illuminated area is still a weak polar ligand. Therefore, if the patterned quantum dot film layer is developed with toluene, the quantum dot materials in the illuminated area and the non-illuminated area are still dissolved in the original non-polar solvent toluene, and are eventually developed out by toluene, and no pattern can be left in the illuminated area and the non-illuminated area.

[0154] For example, in other examples, from the perspective of not affecting the electroluminescent properties of quantum dots, special requirements are placed on the photosensitizer for Example 2 and Example 4 of negative photoresist patterning. In order to minimize the impact of the patterning process on the electrical properties of the final device, the photosensitizer can be selected to have characteristics such as high sensitivity and long wavelength response.

[0155] For example, in another example, in order to form a full-color pattern, and because the polarities of red quantum dots, green quantum dots, and blue quantum dots are different, from the perspective of film retention rate, the polarity of the corresponding photosensitizers is selected differently when forming patterned red quantum dot film layers, patterned green quantum dot film layers, and patterned blue quantum dot film layers.

[0156] For example, the following description is made by taking a full-color pattern including a patterned red quantum dot film layer, a patterned green quantum dot film layer, and a patterned blue quantum dot film layer as an example.

[0157] For example, FIG5 is a process diagram of forming a full-color pattern provided by at least one embodiment of the present disclosure. As shown in FIG5, a red quantum dot composition is applied on a substrate 101 to form a non-polar or weakly polar red quantum dot film 201. The non-polar or weakly polar red quantum dot film 201 includes a non-polar or weakly polar red quantum dot block 201b located in the middle position, and non-polar or weakly polar red quantum dot blocks 201a and 201c located on the left and right sides of the non-polar or weakly polar red quantum dot block 201b, respectively. Then, a mask plate 104 is used to block a part of the non-polar or weakly polar red quantum dot film 201, for example, to block the non-polar or weakly polar red quantum dot blocks 201a and 201c on the left and right sides, and ultraviolet light is used for irradiation so that the ultraviolet light is incident on the non-polar or weakly polar red quantum dot block 201b located in the middle position. The red quantum dot block 201b is formed in the middle position of the non-polar or weakly polar red quantum dot block 201b. The first quantum dot ligand on the quantum dot body included in the non-polar or weakly polar red quantum dot block 201b reacts with the photosensitizer to form a second quantum dot ligand, forming a red quantum dot block 201b' with strong polarity. The first quantum dot ligand is non-polar or weakly polar, and the second quantum dot ligand is strongly polar, that is, the photosensitizer in the red quantum dot composition includes a strong polar group, and the first quantum dot ligand includes a non-polar or weakly polar group. In this way, the exposed red quantum dot block 201b' is easily soluble in a strong polar solvent, while the red quantum dot blocks 201a and 201c in the unexposed area are still non-polar or weakly polar and are not easily soluble in a strong polar solvent. Therefore, the red quantum dot block 201b' located in the middle position can be removed by a strong polar positive developer to obtain a red quantum dot film layer.

[0158] Then, a green quantum dot composition is applied on the red quantum dot film layer to form a strong polarity green quantum dot film 202, which includes a strong polarity green quantum dot block 202b located in the middle, and strong polarity green quantum dot blocks 202a and 202c located on the left and right sides of the strong polarity green quantum dot block 202b, respectively. Then, a mask plate 104 is used to block part of the strong polarity green quantum dot film 202, for example, blocking the strong polarity green quantum dot blocks 202a and 202c on the left and right sides, and irradiating with ultraviolet light so that the ultraviolet light is incident on the strong polarity green quantum dot block 202b located in the middle, so that the quantum dots included in the strong polarity green quantum dot block 202b located in the middle are The first quantum dot ligand on the body reacts with the photosensitizer to form a second quantum dot ligand, the first quantum dot ligand is strongly polar, and the second quantum dot ligand is non-polar or weakly polar, that is, the photosensitizer in the green quantum dot composition includes a non-polar or weakly polar group, and the first quantum dot ligand includes a strongly polar group. In this way, the exposed green quantum dot block 202b' is easily soluble in non-polar or weakly polar solvents, while the green quantum dot blocks 202a and 202c in the unexposed area are still strongly polar and not easily soluble in non-polar or weakly polar solvents. Therefore, a strongly polar negative developer can be used to remove the strongly polar green quantum dot blocks 202a and 202c on the left and right sides, and retain the green quantum dot block 202b' in the middle position to obtain a green quantum dot film layer.

[0159] Finally, a blue quantum dot composition is applied on the red quantum dot film layer and the green quantum dot film layer to form a strong polarity blue quantum dot film 203, wherein the strong polarity blue quantum dot film 203 includes strong polarity blue quantum dot blocks 203a, 203b and 203c sequentially arranged on the red quantum dot block 201a, the green quantum dot block 202b' and the red quantum dot block 201c, and a strong polarity blue quantum dot block 203d located on the right side of the red quantum dot block 201c. Then, a mask plate 104 is used to block part of the strong polarity blue quantum dot film 203, for example, blocking the strong polarity blue quantum dot blocks 203a, 203b and 203c on the red quantum dot block 201a, the green quantum dot block 202b' and the red quantum dot block 201c. 3b and 203c, and irradiated with ultraviolet light so that the ultraviolet light is incident on the strong polar blue quantum dot block 203d located on the right side of the red quantum dot block 201c, so that the first quantum dot ligand on the quantum dot body included in the strong polar blue quantum dot block 203d located on the right side of the red quantum dot block 201c reacts with the photosensitizer to form a second quantum dot ligand, the first quantum dot ligand is strongly polar, and the second quantum dot ligand is non-polar or weakly polar, that is, the photosensitizer in the blue quantum dot composition includes a non-polar or weakly polar group, and the first quantum dot ligand includes a strongly polar group, so that the exposed blue quantum dot block 203d' is easily soluble in a non-polar or weakly polar solvent, while the blue quantum dot blocks 203a and 203b in the unexposed area are easily soluble in a non-polar or weakly polar solvent. and 203c are still highly polar and not easily soluble in non-polar or weakly polar solvents, so a non-polar or weakly polar positive developer can be used to remove the blue quantum dot blocks 203a, 203b and 203c in the unexposed area, retaining the blue quantum dot block 203d' located to the right of the red quantum dot block 201c to obtain a blue quantum dot film layer.

[0160] For example, Figure 6 is another process diagram for forming a full-color pattern provided by at least one embodiment of the present disclosure. As shown in Figure 6, a red quantum dot composition is applied on a substrate 101 to form a non-polar or weakly polar red quantum dot film 201. The non-polar or weakly polar red quantum dot film 201 includes a non-polar or weakly polar red quantum dot block 201b located in the middle position, and non-polar or weakly polar red quantum dot blocks 201a and 201c located on the left and right sides of the non-polar or weakly polar red quantum dot block 201b, respectively. Then, a mask plate 104 is used to block a portion of the non-polar or weakly polar red quantum dot film 201, for example, blocking the non-polar or weakly polar red quantum dot blocks 201a and 201c on the left and right sides, and ultraviolet light is used for irradiation so that the ultraviolet light is incident on the non-polar or weakly polar red quantum dot block 201 located in the middle position. 1b, so that the non-polar or weakly polar red quantum dot block 201b located in the middle position includes a first quantum dot ligand on the quantum dot body that reacts with the photosensitizer to form a second quantum dot ligand, forming a strongly polar red quantum dot block 201b', the first quantum dot ligand is non-polar or weakly polar, and the second quantum dot ligand is strongly polar, that is, the photosensitizer in the red quantum dot composition includes a strongly polar group, and the first quantum dot ligand includes a non-polar or weakly polar group, so that the exposed red quantum dot block 201b' is easily soluble in a strongly polar solvent, while the red quantum dot blocks 201a and 201c in the unexposed area are still non-polar or weakly polar and are not easily soluble in a strongly polar solvent, so that the non-polar or weakly polar red quantum dot blocks 201a and 201c located on the left and right sides can be removed by a non-polar or weakly polar negative developer to obtain a red quantum dot film layer.

[0161] A green quantum dot composition is then applied to the red quantum dot film layer to form a non-polar or weakly polar green quantum dot film 202, which includes a non-polar or weakly polar green quantum dot block 202b located in the middle position, and non-polar or weakly polar green quantum dot blocks 202a and 202c located on the left and right sides of the non-polar or weakly polar green quantum dot block 202b, respectively. Then, a mask plate 104 is used to block a portion of the non-polar or weakly polar green quantum dot film 202, for example, to block the non-polar or weakly polar green quantum dot block 202b located in the middle, and ultraviolet light is used for irradiation, so that the ultraviolet light is incident on the non-polar or weakly polar green quantum dot blocks 202a and 202c located on the left and right sides of the non-polar or weakly polar green quantum dot block 202b, respectively. In this way, the first quantum dot ligand on the quantum dot body included in the non-polar or weakly polar green quantum dot blocks 202a and 202c located on the left and right sides reacts with the photosensitizer to form a second quantum dot ligand, and the first quantum dot ligand is non-polar or weakly polar. The second quantum dot ligand is strongly polar, that is, the photosensitizer in the green quantum dot composition includes a strongly polar group, and the first quantum dot ligand includes a non-polar or weakly polar group. In this way, the exposed green quantum dot blocks 202a' and 202c' are easily soluble in a strongly polar solvent, while the green quantum dot blocks 202b in the unexposed area are still non-polar or weakly polar and are not easily soluble in a strongly polar solvent. Therefore, a non-polar or weakly polar positive developer can be used to remove the non-polar or weakly polar green quantum dot block 202b in the middle position, and retain the strongly polar green quantum dot blocks 202a' and 202c' on the left and right sides to obtain a green quantum dot film layer.

[0162] Finally, a blue quantum dot composition is applied on the red quantum dot film layer and the green quantum dot film layer to form a non-polar or weakly polar blue quantum dot film 203, which includes non-polar or weakly polar blue quantum dot blocks 203a, 203b and 203c sequentially arranged on the green quantum dot block 202a', the red quantum dot block 201b' and the green quantum dot block 202c', and a non-polar blue quantum dot block 203a located on the right side of the green quantum dot block 202c'. Or weak polarity blue quantum dot block 203d, then use the mask plate 104 to block part of the non-polar or weak polarity blue quantum dot film 203, for example, block the non-polar or weak polarity blue quantum dot blocks 203a, 203b and 203c on the green quantum dot block 202a', the red quantum dot block 201b' and the green quantum dot block 202c', and use ultraviolet light to irradiate, so that the ultraviolet light is incident on the non-polar or weak polarity blue quantum dot block 203d located on the right side of the green quantum dot block 202c'. On the weakly polar blue quantum dot block 203d, the non-polar or weakly polar blue quantum dot block 203d located on the right side of the green quantum dot block 202c' includes a first quantum dot ligand on the quantum dot body and a photosensitizer that reacts to form a second quantum dot ligand. The first quantum dot ligand is non-polar or weakly polar, and the second quantum dot ligand is strongly polar. That is, the photosensitizer in the blue quantum dot composition includes a strongly polar group, and the first quantum dot ligand includes a non-polar or weakly polar group. The blue quantum dot block 203d' is easily soluble in strongly polar solvents, while the blue quantum dot blocks 203a, 203b and 203c in the unexposed area are still non-polar or weakly polar and easily soluble in non-polar or weakly polar solvents. Therefore, a non-polar or weakly polar positive developer can be used to remove the blue quantum dot blocks 203a, 203b and 203c in the unexposed area, retaining the blue quantum dot block 203d' located to the right of the green quantum dot block 202c' to obtain a blue quantum dot film layer.

[0163] For example, Figure 7 is another process diagram for forming a full-color pattern provided by at least one embodiment of the present disclosure. As shown in Figure 7, a red quantum dot composition is applied to a substrate 101 to form a strong polarity red quantum dot film 201, and the strong polarity red quantum dot film 201 includes a strong polarity red quantum dot block 201b located in the middle position, and strong polarity red quantum dot blocks 201a and 201c located on the left and right sides of the strong polarity red quantum dot block 201b, respectively. Then, a mask plate 104 is used to block part of the strong polarity red quantum dot film 201, for example, blocking the strong polarity red quantum dot blocks 201a and 201c on the left and right sides, and ultraviolet light is used for irradiation so that the ultraviolet light is incident on the strong polarity red quantum dot block 201b located in the middle position, so that the strong polarity red quantum dot block 201b located in the middle position is The color quantum dot block 201b includes a first quantum dot ligand on the quantum dot body that reacts with the photosensitizer to form a second quantum dot ligand, forming a non-polar or weakly polar red quantum dot block 201b'. The first quantum dot ligand is strongly polar, and the second quantum dot ligand is non-polar or weakly polar, that is, the photosensitizer in the red quantum dot composition includes a non-polar or weakly polar group, and the first quantum dot ligand includes a strongly polar group. In this way, the exposed red quantum dot block 201b' is easily soluble in non-polar or weakly polar solvents, while the red quantum dot blocks 201a and 201c in the unexposed area are still strongly polar and not easily soluble in non-polar or weakly polar solvents. Therefore, the strongly polar negative developer can be used to remove the strongly polar red quantum dot blocks 201a and 201c on the left and right sides to obtain a red quantum dot film layer.

[0164] A green quantum dot composition is then applied to the red quantum dot film layer to form a strong polarity green quantum dot film 202, which includes a strong polarity green quantum dot block 202b located in the middle position, and strong polarity green quantum dot blocks 202a and 202c located on the left and right sides of the strong polarity green quantum dot block 202b, respectively. Then, a mask plate 104 is used to block part of the strong polarity green quantum dot film 202, for example, the strong polarity green quantum dot block 202b located in the middle is blocked, and ultraviolet light is used for irradiation, so that the ultraviolet light is incident on the strong polarity green quantum dot blocks 202a and 202c located on the left and right sides of the strong polarity green quantum dot block 202b, respectively. In this way, the first quantum dot ligand on the quantum dot body included in the strong polarity green quantum dot blocks 202a and 202c located on the left and right sides reacts with the photosensitizer to form a second quantum dot ligand, the first quantum dot ligand is strongly polar, and the second quantum dot ligand is non-polar or weakly polar. Polar, that is, the photosensitizer in the green quantum dot composition includes a non-polar or weakly polar group, and the first quantum dot ligand includes a strongly polar group. In this way, the exposed green quantum dot blocks 202a' and 202c' are easily soluble in non-polar or weakly polar solvents, while the green quantum dot blocks 202b in the unexposed area are still strongly polar and not easily soluble in non-polar or weakly polar solvents. Therefore, a strongly polar negative developer can be used to remove the strongly polar green quantum dot block 202b located in the middle position, and retain the non-polar or weakly polar green quantum dot blocks 202a' and 202c' located on the left and right sides to obtain a green quantum dot film layer.

[0165] Finally, a blue quantum dot composition is applied on the red quantum dot film layer and the green quantum dot film layer to form a strong polarity blue quantum dot film 203, which includes strong polarity blue quantum dot blocks 203a, 203b and 203c arranged on the green quantum dot block 202a', the red quantum dot block 201b' and the green quantum dot block 202c' in sequence, and a strong polarity blue quantum dot block 203d located on the right side of the green quantum dot block 202c'. Then, a mask plate 104 is used to block part of the strong polarity blue quantum dot film 203, for example, blocking the strong polarity blue quantum dot blocks 203a, 203b and 203c on the green quantum dot block 202a', the red quantum dot block 201b' and the green quantum dot block 202c', and irradiating with ultraviolet light so that the ultraviolet light is incident on the strong polarity blue quantum dot block located on the right side of the green quantum dot block 202c'. On 203d, the blue quantum dot block 203d with strong polarity located on the right side of the green quantum dot block 202c' includes a first quantum dot ligand on the quantum dot body that reacts with the photosensitizer to form a second quantum dot ligand. The first quantum dot ligand is strongly polar, and the second quantum dot ligand is non-polar or weakly polar, that is, the photosensitizer in the blue quantum dot composition includes a non-polar or weakly polar group, and the first quantum dot ligand includes a strongly polar group. In this way, the exposed blue quantum dot block 203d' is easily soluble in non-polar or weakly polar solvents, while the blue quantum dot blocks 203a, 203b and 203c in the unexposed area are still strongly polar and easily soluble in strongly polar solvents. Therefore, a strongly polar negative developer can be used to remove the blue quantum dot blocks 203a, 203b and 203c in the unexposed area, retaining the blue quantum dot block 203d' located on the right side of the green quantum dot block 202c' to obtain a blue quantum dot film layer.

[0166] For example, Figure 8 is another process diagram for forming a full-color pattern provided by at least one embodiment of the present disclosure. As shown in Figure 8, a red quantum dot composition is applied to a substrate 101 to form a strong polarity red quantum dot film 201, and the strong polarity red quantum dot film 201 includes a strong polarity red quantum dot block 201b located in the middle position, and strong polarity red quantum dot blocks 201a and 201c located on the left and right sides of the strong polarity red quantum dot block 201b, respectively. Then, a mask plate 104 is used to block part of the strong polarity red quantum dot film 201, for example, blocking the strong polarity red quantum dot blocks 201a and 201c on the left and right sides, and ultraviolet light is used for irradiation so that the ultraviolet light is incident on the strong polarity red quantum dot block 201b located in the middle position, so that the strong polarity red quantum dot block 201b located in the middle position is The color quantum dot block 201b includes a first quantum dot ligand on the quantum dot body that reacts with the photosensitizer to form a second quantum dot ligand, forming a non-polar or weakly polar red quantum dot block 201b'. The first quantum dot ligand is strongly polar, and the second quantum dot ligand is non-polar or weakly polar, that is, the photosensitizer in the red quantum dot composition includes a non-polar or weakly polar group, and the first quantum dot ligand includes a strongly polar group. In this way, the exposed red quantum dot block 201b' is easily soluble in non-polar or weakly polar solvents, while the red quantum dot blocks 201a and 201c in the unexposed area are still strongly polar and not easily soluble in non-polar or weakly polar solvents. Therefore, the strongly polar negative developer can be used to remove the strongly polar red quantum dot blocks 201a and 201c on the left and right sides to obtain a red quantum dot film layer.

[0167] Then, a green quantum dot composition is applied on the red quantum dot film layer to form a strong polarity green quantum dot film 202, wherein the strong polarity green quantum dot film 202 includes a strong polarity green quantum dot block 202b located in the middle position, and strong polarity green quantum dot blocks 202a and 202c located on the left and right sides of the strong polarity green quantum dot block 202b, respectively. Then, a mask plate 104 is used to block part of the strong polarity green quantum dot film 202, for example, the strong polarity green quantum dot block 202b located in the middle position is blocked, and ultraviolet light is used for irradiation so that the ultraviolet light is incident on the strong polarity green quantum dot blocks 202a and 202c located on the left and right sides. In this way, the strong polarity green quantum dot blocks 202a and 202c located on the left and right sides include quantum dots. The first quantum dot ligand on the quantum dot body reacts with the photosensitizer to form a second quantum dot ligand, the first quantum dot ligand is strongly polar, and the second quantum dot ligand is non-polar or weakly polar, that is, the photosensitizer in the green quantum dot composition includes a non-polar or weakly polar group, and the first quantum dot ligand includes a strongly polar group. In this way, the exposed green quantum dot blocks 202a' and 202c' are easily soluble in non-polar or weakly polar solvents, while the green quantum dot blocks 202b in the unexposed area are still strongly polar and not easily soluble in non-polar or weakly polar solvents. Therefore, a strongly polar negative developer can be used to remove the strongly polar green quantum dot block 202b located in the middle position, retaining the green quantum dot blocks 202a' and 202c' located on the left and right sides to obtain a green quantum dot film layer.

[0168] Finally, a blue quantum dot composition is applied on the red quantum dot film layer and the green quantum dot film layer to form a strong polarity blue quantum dot film 203, which includes strong polarity blue quantum dot blocks 203a, 203b and 203c arranged on the green quantum dot block 202a', the red quantum dot block 201b' and the green quantum dot block 202c' in sequence, and a strong polarity blue quantum dot block 203d located on the right side of the green quantum dot block 202c'. Then, a mask plate 104 is used to block part of the strong polarity blue quantum dot film 203, for example, blocking the strong polarity blue quantum dot blocks 203a, 203b and 203c on the green quantum dot block 202a', the red quantum dot block 201b' and the green quantum dot block 202c', and irradiating with ultraviolet light so that the ultraviolet light is incident on the strong polarity blue quantum dot block 203 located on the right side of the green quantum dot block 202c'. d, the first quantum dot ligand on the quantum dot body included in the strongly polar blue quantum dot block 203d located on the right side of the green quantum dot block 202c' reacts with the photosensitizer to form a second quantum dot ligand, the first quantum dot ligand is strongly polar, and the second quantum dot ligand is non-polar or weakly polar, that is, the photosensitizer in the blue quantum dot composition includes a non-polar or weakly polar group, and the first quantum dot ligand includes a strongly polar group. In this way, the exposed blue quantum dot block 203d' is easily soluble in non-polar or weakly polar solvents, while the blue quantum dot blocks 203a, 203b and 203c in the unexposed area are still strongly polar and not easily soluble in non-polar or weakly polar solvents. Therefore, the blue quantum dot blocks 203a, 203b and 203c in the unexposed area can be removed with a strongly polar negative developer, retaining the blue quantum dot block 203d' located on the right side of the green quantum dot block 202c' to obtain a blue quantum dot film layer.

[0169] For example, the process of forming a full-color pattern may also be other schemes besides the process diagrams shown in Figures 5 to 8 above. By adjusting the blocking position of the mask plate and the exposure position, a pattern of any color combination can be obtained. The embodiments of the present disclosure are not limited to this.

[0170] At least one embodiment of the present disclosure further provides a quantum dot display device, which includes a quantum dot film layer prepared using the quantum dot composition in any of the above embodiments. The other layer structures included in the quantum dot display device can refer to conventional designs, and the embodiments of the present disclosure are not limited to this.

[0171] For example, in the quantum dot display device provided in the embodiments of the present disclosure, the property of the first quantum dot ligand of the quantum dot that changes in polarity after being connected to the second functional group in the photosensitizer can be utilized through a carbon-hydrogen insertion reaction or a carbon-carbon double bond addition reaction, so as to achieve the purpose of subsequent photolithographic patterning of the quantum dot film layer, and at the same time, the molecular weight of the second quantum dot ligand can be made greater than the molecular weight of the first quantum dot ligand. In the process of preparing a patterned quantum dot film layer, a mask is placed on the quantum dot film, and ultraviolet light is used to irradiate a partial area of ​​the quantum dot film, so that the polarity of the ligands on the surface of the quantum dot body in the quantum dot material in the irradiated area is changed, that is, the polarity of the ligands on the surface of the quantum dot body in the area of ​​the quantum dot film irradiated by ultraviolet light is different from the polarity of the ligands on the surface of the quantum dot body in the area of ​​the quantum dot film not irradiated by ultraviolet light, and the original environment of the first quantum dot ligand of the quantum dot body can basically be maintained, so the impact on the performance of the electroluminescent device finally formed is very small, that is, the coordination group included in the first quantum dot ligand is not changed, so as not to affect the interaction between the first quantum dot ligand and the quantum dot body, nor to cause the first quantum dot ligand to fall off from the surface of the quantum dot body, so as not to introduce defects, and thus the patterning of the quantum dot film can be completed by selecting a suitable good solvent for the quantum dot material to clean a part of the quantum dot film according to the pattern of the quantum dot film layer to be formed. For example, the quantum dot material in the area exposed to light remains, while the quantum dot material in the area not exposed to light is washed away, or vice versa. This provides a simple and efficient method for patterning quantum dot films while avoiding the introduction of photoresist that would otherwise damage the optoelectronic properties of the quantum dots.

[0172] For example, Figure 9 is a schematic diagram of the cross-sectional structure of a quantum dot display device provided in at least one embodiment of the present disclosure. As shown in Figure 9, the quantum dot display device is a quantum dot light-emitting device 300, and the quantum dot light-emitting device 300 includes a first electrode 301, a second electrode 303 and a quantum dot film layer 302 sandwiched between the first electrode 301 and the second electrode 303.

[0173] For example, in the structure shown in FIG9 , the first electrode 301 can be a cathode and the second electrode 303 can be an anode; alternatively, the first electrode 301 can be an anode and the second electrode 303 can be a cathode. Furthermore, in the structure shown in FIG9 , the light-emitting principle of the quantum dot film layer in the quantum dot light-emitting device is electroluminescence.

[0174] For example, as shown in Figure 9, the quantum dot light-emitting device 300 may further include a hole transport layer 304, a hole injection layer 305, an electron transport layer 306, and an electron injection layer 307. The quantum dot light-emitting device 300 may be an upright structure or an inverted structure. Figure 8 takes the upright structure as an example for illustration. For example, in the upright structure, the quantum dot light-emitting device includes a second electrode 303, a hole injection layer 305, a hole transport layer 304, a quantum dot film layer 302, an electron transport layer 306, an electron injection layer 307, and a first electrode 301 stacked in sequence on a substrate, wherein the first electrode 301 is a cathode and the second electrode 303 is an anode. In the inverted structure, the quantum dot light-emitting device includes a first electrode 301, an electron injection layer, an electron transport layer, a quantum dot film layer 302, a hole transport layer, a hole injection layer, and a second electrode 303 stacked in sequence on a substrate, wherein the first electrode 301 is a cathode and the second electrode 303 is an anode.

[0175] For example, the material of the hole transport layer 304 includes any one of N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-diphenyl-4,4'-diamine (NPB), 4,4',4"-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), and 4,4-2-[N-(4-carbazophenyl)-N-phenylamino]biphenyl (CPB), but is not limited thereto.

[0176] For example, the hole injection layer 305 may be made of metal oxide MeO, such as MoO3, or may be made of p-type doped MeO (metal oxide)-TPD (N,N'10-bis(3-methylphenyl)-N,N'-diphenyl-1,1'-diphenyl-4,4'-diamine): F4TCNQ (N,N,N',N'-tetramethoxyphenyl)-p-diaminobiphenyl: 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone) or m-MTDATA: F4TCNQ (4,4',4"-tris(N-3-methylphenyl-N-phenylamino)triphenylamine: 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone), etc.

[0177] For example, the material of the second electrode 303 can be a transparent conductive material, which includes indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium oxide (IGO), gallium zinc oxide (GZO), zinc oxide (ZnO), indium oxide (In2O3), aluminum zinc oxide (AZO) and carbon nanotubes, and the second electrode 303 is an anode.

[0178] For example, the material of the first electrode 301 includes magnesium, aluminum, lithium single metal or magnesium aluminum alloy (MgAl), lithium aluminum alloy (LiAl), etc., and the first electrode 301 is a cathode.

[0179] For example, the material of the electron injection layer 307 includes: lithium oxide (Li2O), cesium oxide (Cs2O), sodium oxide (Na2O), lithium carbonate (Li2CO3), cesium carbonate (Cs2CO3), or sodium carbonate (Na2CO3), lithium fluoride (LiF), cesium fluoride (CsF), sodium fluoride (NaF), calcium fluoride (CaF2), 8-hydroxyquinoline aluminum (Alq3), 8-hydroxyquinoline lithium (Liq), 8-hydroxyquinoline gallium, bis[2-(2-hydroxyphenyl-1)-pyridine]beryllium, 2-(4-diphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD).

[0180] For example, in one example, the material of the electron transport layer 306 includes at least one of zinc oxide, zinc oxide doped with magnesium ions, and zinc oxide doped with cesium ions.

[0181] For example, in one example, the material of the electron transport layer 306 includes any one of 4,7-diphenyl-1,10-o-phenanthroline (BPhen), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBI), and an n-doping electron transport material, but is not limited thereto. The n-doping electron transport material includes, for example, 2,9-dimethyl-4,7-biphenyl-1,10-o-phenanthroline (BCP):Li2CO3, 8-hydroxyquinoline aluminum (Alq3):Mg, TPBI:Li, etc., but the embodiments of the present disclosure are not limited thereto.

[0182] It should be noted that the materials and structures of the above-mentioned first electrode 301 and the second electrode 303 are only an example in the embodiments of the present disclosure. The first electrode and the second electrode can also be made of other materials. Depending on the materials of the first electrode and the second electrode, they can be divided into single-sided light-emitting quantum dot devices and double-sided light-emitting quantum dot devices. When the material of one electrode of the anode and the cathode is opaque or semi-transparent material, it is a single-sided light-emitting quantum dot device. When the materials of the anode and the cathode are both transparent and / or semi-transparent materials, it is a double-sided light-emitting quantum dot device.

[0183] As needed, the materials of the first electrode and the second electrode can be selected to be suitable for top light emitting type, bottom light emitting type and double-sided light emitting type respectively. The embodiments of the present disclosure do not limit the selection of the materials of the first electrode and the second electrode.

[0184] For example, Figure 10 is a schematic diagram of the cross-sectional structure of another quantum dot display device provided in at least one embodiment of the present disclosure. As shown in Figure 10, the quantum dot display device is a quantum dot color conversion device 400. The quantum dot color conversion device 400 includes a light-emitting substrate 401 and a quantum dot film layer 402 located on the light-emitting substrate 401. For example, the light-emitting principle of the quantum dot film layer in the quantum dot color conversion device is photoluminescence.

[0185] For example, in the structure shown in FIG10 , the light-emitting substrate 401 is a blue light OLED light-emitting substrate.

[0186] For example, a pixel definition layer 403 is provided on a blue OLED light-emitting substrate, and then a red quantum dot film layer and a green quantum dot film layer are sequentially formed in the openings defined by the pixel definition layer 403. Since the blue OLED light-emitting substrate itself can emit blue light, the blue light can excite the red quantum dot film layer to emit red light, and the blue light can also excite the green quantum dot film layer to emit green light, thereby obtaining a full-color quantum dot display device. The embodiments of the present disclosure do not limit the specific structure of the above-mentioned blue OLED light-emitting substrate, and the specific structure can be determined according to actual conditions.

[0187] For example, in the structure shown in FIG10 , the light-emitting substrate 401 can be a Micro LED (Micro Light Emitting Diode) light-emitting substrate, and the light-emitting color of the Micro LED light-emitting substrate 401 can be blue. By respectively providing a red quantum dot film layer and a green quantum dot film layer on the light-emitting unit of the blue Micro LED light-emitting substrate 401, a full-color quantum dot display device based on Micro LED technology can also be obtained. The embodiments of the present disclosure do not limit the specific structure of the above-mentioned blue Micro LED light-emitting substrate 401, and the specific structure can be determined according to actual conditions.

[0188] For example, Figure 11 is a schematic diagram of the cross-sectional structure of another quantum dot display device provided in at least one embodiment of the present disclosure. As shown in Figure 11, the quantum dot display device is a quantum dot color conversion device 500. The quantum dot color conversion device 500 includes a light-emitting substrate 501 and a quantum dot film layer 502 located on the light-emitting substrate 501. For example, the light-emitting principle of the quantum dot film layer in the quantum dot color conversion device is photoluminescence.

[0189] For example, in the structure shown in FIG11 , the light-emitting substrate 501 is a white light OLED light-emitting substrate.

[0190] For example, a pixel definition layer 503 is provided on a white light OLED light-emitting substrate, and then a red quantum dot film layer, a green quantum dot film layer, and a blue quantum dot film layer are sequentially formed in the openings defined by the pixel definition layer 503. White light can excite the red quantum dot film layer to emit red light, the green quantum dot film layer to emit green light, and the blue quantum dot film layer to emit blue light, thereby obtaining a full-color quantum dot display device. The embodiments of the present disclosure do not limit the specific structure of the white light OLED light-emitting substrate, and the specific structure can be determined according to actual conditions.

[0191] Based on the same inventive concept, an embodiment of the present disclosure further provides a display device, which includes the quantum dot light-emitting device provided in any of the above embodiments. For example, in a specific implementation, the display device provided in the embodiment of the present invention can be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame, a navigator, etc. Other essential components of the display device should be understood by those of ordinary skill in the art and will not be described in detail here, nor should they be used to limit the present invention. The implementation of the display device can refer to the embodiments of the quantum dot light-emitting device described above, and repeated parts will not be described in detail.

[0192] There are a few points to note:

[0193] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure. Other structures may refer to conventional designs.

[0194] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thickness of layers or regions is exaggerated or reduced, that is, these drawings are not drawn according to the actual scale.

[0195] (3) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to form new embodiments.

[0196] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A quantum dot composition, comprising: a mixture of quantum dot materials and photosensitizers, wherein, the quantum dot materials include a quantum dot body and a first quantum dot ligand on the surface of the quantum dot body; the photosensitizer is configured to react with the first quantum dot ligand under light irradiation to form a second quantum dot ligand, the molecular weight of the second quantum dot ligand is greater than that of the first quantum dot ligand, and the second quantum dot ligand and the first quantum dot ligand have different polarities.

2. The quantum dot composition according to claim 1, wherein, the polarity index of the second quantum dot ligand is greater than or equal to 0 and less than 3.6, and correspondingly the polarity index of the first quantum dot ligand is greater than 3.6 and less than 13; or, the polarity index of the first quantum dot ligand is greater than or equal to 0 and less than 3.6, and correspondingly the polarity index of the second quantum dot ligand is greater than 3.6 and less than 13.

3. The quantum dot composition according to claim 1 or 2, wherein, the first quantum dot ligand includes a coordination group combined with the surface of the quantum dot body, a first linking group connected to the coordination group, and a first functional group connected to the first linking group; the photosensitizer includes a photosensitive group, a second linking group connected to the photosensitive group, and a second functional group connected to the second linking group; the first functional group and the second functional group have different polarities.

4. The quantum dot composition according to claim 3, wherein, the first quantum dot ligand includes a C-H bond, and the photosensitive group is configured to perform a carbene insertion reaction with the C-H bond included in the first quantum dot ligand under light irradiation to form the second quantum dot ligand.

5. The quantum dot composition according to claim 4, wherein, the photosensitive group forms at least one of a nitrene, a carbonyl radical, and a carbene under light irradiation, and at least one of the nitrene, the carbonyl radical, and the carbene performs a carbene insertion reaction with the C-H bond included in the first quantum dot ligand to form the second quantum dot ligand.

6. The quantum dot composition according to claim 4 or 5, wherein, the photosensitive group includes at least one of azide, benzophenone, and bisaziridine.

7. The quantum dot composition according to any one of claims 3 to 6, wherein, the quantum dot ligand includes a C═C bond, and the photosensitive group is configured to perform an addition reaction with the C═C bond included in the first quantum dot ligand under light irradiation to form the second quantum dot ligand.

8. The quantum dot composition according to claim 7, wherein, the photosensitive group forms a nitrene under light irradiation, and the nitrene performs an addition reaction with the C═C bond included in the first quantum dot ligand to form the second quantum dot ligand.

9. The quantum dot composition according to claim 7 or 8, wherein, the photosensitive group includes azide.

10. The quantum dot composition according to any one of claims 2 to 9, wherein, the coordination group includes at least one of a mercapto group, a carboxyl group, an amino group, a phosphino group, and a phosphinyloxy group; The first linking group includes at least one of a C1-C30 straight-chain alkyl group, an unsaturated hydrocarbon chain having one or more double bonds or benzene rings, and a polyether chain segment compound; The first functional group includes at least one of a methyl group, a phenyl group, a sulfonic acid group, a carboxyl group, a nitroso group, a cyano group, a hydroxyl group, an amide group, a phenolic hydroxyl group, a mercapto group, an amino group, an aldehyde group, a carbonyl group, an alkenyl group, an alkynyl group, an ether bond, and a thioether bond.

11. The quantum dot composition according to claim 10, wherein, The second linking group includes a C1-C30 straight-chain alkyl group and an unsaturated hydrocarbon chain having one or more double bonds or benzene rings; The second functional group includes at least one of a sulfonic acid group, a carboxyl group, a nitroso group, a cyano group, a hydroxyl group, an amide group, a phenolic hydroxyl group, a mercapto group, an amino group, a methyl group, an aldehyde group, an alkyl group, a carbonyl group, an alkenyl group, an alkynyl group, an ether bond, and a thioether bond.

12. The quantum dot composition according to claim 11, wherein, The second functional group is at least one of a sulfonic acid group, a carboxyl group, a nitroso group, a cyano group, a hydroxyl group, an amide group, a phenolic hydroxyl group, a mercapto group, and an amino group, and the first functional group is at least one of a methyl group, an aldehyde group, a carbonyl group, an alkenyl group, an alkynyl group, an ether bond, and a thioether bond; or The second functional group is at least one of a methyl group, an aldehyde group, an alkyl group, a carbonyl group, an alkenyl group, an alkynyl group, an ether bond, and a thioether bond, and the first functional group is at least one of a phenyl group, a sulfonic acid group, a carboxyl group, a nitroso group, a cyano group, a hydroxyl group, an amide group, a phenolic hydroxyl group, a mercapto group, and an amino group.

13. The quantum dot composition according to any one of claims 1-12 further includes a solvent. Wherein, the solvent is a weakly polar solvent or a non-polar solvent, the first functional group is a weakly polar group or a non-polar group, the corresponding second functional group is a strongly polar group, and the dielectric constant of the weakly polar solvent or the non-polar solvent is less than 3.

6.

14. The quantum dot composition according to claim 13, wherein, The first quantum dot ligand is 1-octanethiol or oleic acid, the photosensitizer is 2,3,4,5-tetrafluoro-4-azidobenzoic acid or 3-benzoylbenzoic acid, and the solvent is the weakly polar solvent or the non-polar solvent.

15. The quantum dot composition according to claim 14, wherein, The weakly polar solvent or the non-polar solvent includes at least one of cyclohexane, petroleum ether, octane, trimethylpentane, carbon tetrachloride, trichlorotrifluoroethane, p-xylene, chlorobenzene, o-dichlorobenzene, diethyl ether, diethyl ether, tetrahydrofuran, hexane, pentane, toluene, and chlorobenzene.

16. The quantum dot composition according to any one of claims 1-12 further includes a solvent. Wherein, the solvent is a strongly polar solvent, the first functional group is a strongly polar group, the corresponding second functional group is a weakly polar group or a non-polar group, and the dielectric constant of the strongly polar solvent is greater than or equal to 3.

6.

17. The quantum dot composition according to claim 16, wherein, The first quantum dot ligand is 6-mercaptohexanol, the photosensitizer is 2,3,4,5-tetrafluoro-4-azidostearylbenzene, and the solvent is the strongly polar solvent.

18. The quantum dot composition according to claim 17, Among them, the strong polar solvent includes at least one of methanol, ethanol, isopropanol, ethyl acetate, acetonitrile, acetone, acetic acid, pyridine, N,N-dimethylformamide, and dimethyl sulfoxide.

19. A patterning method for a quantum dot film layer, comprising: providing a substrate; applying the quantum dot composition according to any one of claims 1 to 18 on the substrate to form a quantum dot thin film; using a mask plate to shield the quantum dot thin film, and irradiating a partial area of the quantum dot thin film with light to increase the molecular weight of the quantum dot ligand in the partial area and change the polarity of the quantum dot ligand; developing the quantum dot thin film with a developer to obtain a patterned quantum dot film layer.

20. The patterning method for a quantum dot film layer according to claim 19, wherein, irradiating a partial area of the quantum dot thin film with light to increase the molecular weight of the quantum dot ligand in the partial area and change the polarity of the quantum dot ligand includes: using a mask plate to shield the quantum dot thin film, and irradiating a partial area of the quantum dot thin film with ultraviolet light or infrared light, so that the molecular weight of the quantum dot ligand in the partial area irradiated by the ultraviolet light or infrared light increases and the second quantum dot ligand is formed.

21. The patterning method for a quantum dot film layer according to claim 19 or 20, wherein, developing the quantum dot thin film with a developer to obtain a patterned quantum dot film layer includes: using a negative developer to remove the quantum dot thin film in the area other than the illuminated area to obtain a patterned quantum dot film layer; or using a positive developer to remove the quantum dot thin film in the illuminated area to obtain a patterned quantum dot film layer.

22. The patterning method for a quantum dot film layer according to claim 21, wherein, the polarity of the quantum dot ligand is less than the polarity of the photosensitizer, and forming the patterned quantum dot film layer includes: using a non-polar negative developer to remove the quantum dot thin film in the area other than the illuminated area to obtain the patterned quantum dot film layer; or using a polar positive developer to remove the quantum dot thin film in the illuminated area to obtain a patterned quantum dot film layer.

23. The patterning method for a quantum dot film layer according to claim 21, wherein, the polarity of the quantum dot ligand is greater than the polarity of the photosensitizer, and forming the patterned quantum dot film layer includes: using a polar negative developer to remove the quantum dot thin film in the area other than the illuminated area to obtain the patterned quantum dot film layer; or using a non-polar positive developer to remove the quantum dot thin film in the illuminated area to obtain a patterned quantum dot film layer.

24. A quantum dot display device, including a quantum dot film layer prepared from the quantum dot composition according to any one of claims 1 to 18.

25. The quantum dot display device according to claim 24, wherein, the quantum dot display device is a quantum dot light-emitting device, and the quantum dot light-emitting device includes a first electrode, a second electrode, and the quantum dot film layer sandwiched between the first electrode and the second electrode.

26. The quantum dot display device according to claim 24, wherein, the quantum dot display device is a quantum dot color conversion device, and the quantum dot color conversion device includes a light-emitting substrate and the quantum dot film layer located on the light-emitting substrate.

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