Quantum dot material, patterning method of quantum dot layer and related application

Abstract

A quantum dot material, a patterning method of a quantum dot layer and related applications, the quantum dot material comprises a quantum dot body and a first ligand connected to the surface of the quantum dot body, the first ligand comprises a first coordination group, a first dissolving group and a first photosensitive group, the first coordination group is in coordination connection with the quantum dot body, and the first dissolving group is in coordination connection with the first photosensitive group. The first dissolving group is connected between the first coordination group and the first photosensitive group; wherein the first photosensitive group is configured to be subjected to bond breaking under an illumination condition, so that the first ligand is decomposed into a first unit containing a first coordination group and a first dissolving group, and the solubility of the first unit is different from that of the first ligand.

Description

A quantum dot material, a patterning method for quantum dot layers, and related applications. Technical Field

[0001] This disclosure relates to the field of quantum dot technology, and in particular to a quantum dot material, a method for patterning quantum dot layers, and related applications. Background Technology

[0002] Quantum dots (QDs), also known as nanocrystals, are nanoparticles composed of group II-VI or III-V elements, and have advantages such as high quantum yield, narrow emission peak, tunable emission spectrum, and high photochemical stability.

[0003] With the in-depth development of quantum dot fabrication technology, the stability and luminous efficiency of quantum dots have been continuously improved, leading to ongoing research on quantum light-emitting diodes (QLEDs). QLEDs possess advantages such as self-illumination, low power consumption, and a wide color gamut, attracting widespread attention from academia and industry, and their application prospects in the display field are increasingly bright. However, the efficiency of QLEDs has not yet reached mass production levels, one important reason being the lack of breakthroughs in high-resolution patterning technology.

[0004] The inorganic nanoparticle characteristics of quantum dots make it impossible to form films and pattern them by vapor deposition, and it is difficult to achieve high resolution by inkjet printing.

[0005] Summary of the Invention

[0006] This disclosure provides a method for patterning quantum dot materials and quantum dot layers, along with related applications. The specific solution is as follows:

[0007] This disclosure provides a quantum dot material, including a quantum dot body and a first ligand attached to the surface of the quantum dot body. The first ligand includes a first coordinating group, a first dissolving group, and a first photosensitive group. The first coordinating group is coordinated with the quantum dot body, and the first dissolving group is connected between the first coordinating group and the first photosensitive group. The first photosensitive group is configured to undergo bond breaking under light irradiation, causing the first ligand to decompose into a first unit containing the first coordinating group and the first dissolving group. The first unit and the first ligand have different solubilities.

[0008] In one possible implementation, in the quantum dot material provided in the embodiments of this disclosure, the first photosensitive group includes a tert-butoxycarbonyl group.

[0009] In one possible implementation, in the quantum dot material provided in the embodiments of this disclosure, the first dissolving group has the following structure:

[0010] Where n is any integer from 1 to 5, and * represents the connection site.

[0011] In one possible implementation, in the quantum dot material provided in the embodiments of this disclosure, the first coordinating group includes at least one of amino, carboxylic acid, mercapto, phosphino, phosphoxy, or dithiol.

[0012] In one possible implementation, in the quantum dot material provided in the embodiments of this disclosure, the first ligand further includes a first linking group located between the first photosensitive group and the first dissolving group, the first linking group comprising an alkylene group having 1-6 carbon atoms.

[0013] In one possible implementation, in the quantum dot material provided in the embodiments of this disclosure, the first ligand further includes an imino group located between the first photosensitive group and the first dissolving group.

[0014] In one possible implementation, in the quantum dot material provided in the embodiments of this disclosure, the first ligand further includes a second linking group located between the first coordinating group and the first dissolving group, the second linking group comprising an alkylene group having 1-6 carbon atoms.

[0015] In one possible implementation, in the quantum dot material provided in the embodiments of this disclosure, the structure of the first ligand includes at least one of the following: Where n is any integer from 1 to 5.

[0016] In one possible implementation, the quantum dot material provided in the embodiments of this disclosure further includes a second ligand connected to the surface of the quantum dot body. The second ligand includes a second coordinating group, a second dissolving group, and a second photosensitive group. The second coordinating group is coordinated with the quantum dot body, and the second dissolving group is connected between the second coordinating group and the second photosensitive group. The second photosensitive group is configured to undergo a cross-linking reaction under the light irradiation condition to form a cross-linked network ligand, and the cross-linked network ligand has the same solubility as the first unit.

[0017] In one possible implementation, in the quantum dot material provided in the embodiments of this disclosure, the second photosensitive group includes a carbon-carbon double bond.

[0018] In one possible implementation, in the quantum dot material provided in the embodiments of this disclosure, the second photosensitive group has the following structure:

[0019] R1 includes alkyl groups with 1-4 carbon atoms, and * indicates a linking site.

[0020] In one possible implementation, in the quantum dot material provided in the embodiments of this disclosure, the second dissolving group has the following structure:

[0021] R2 includes alkylene groups with 1-3 carbon atoms, and * indicates a linking site.

[0022] In one possible implementation, in the quantum dot material provided in the embodiments of this disclosure, the second coordinating group includes at least one of amino, carboxylic acid, mercapto, phosphin, phosphoxy, or dithiol.

[0023] In one possible implementation, in the quantum dot material provided in the embodiments of this disclosure, the second ligand further includes a third linking group located between the second coordinating group and the second dissolving group, the third linking group comprising an alkylene group having 1-6 carbon atoms.

[0024] In one possible implementation, in the quantum dot material provided in the embodiments of this disclosure, the structure of the second ligand includes...

[0025] Accordingly, embodiments of this disclosure also provide a method for patterning quantum dot layers, including:

[0026] The quantum dot material and photoinitiator provided in the embodiments of this disclosure are dissolved in a first solvent to obtain a mixed solution, and the mixed solution is spin-coated onto one side of a substrate to form a quantum dot material film;

[0027] The target area of ​​the quantum dot material film is exposed to light of a preset wavelength. Under the initiation of the photoinitiator, the first photosensitive group of the first ligand in the target area undergoes bond breaking, making the quantum dot material film in the target area insoluble in the first solvent.

[0028] The exposed quantum dot material film is developed using the first solvent to form a patterned quantum dot layer in the target area.

[0029] In one possible implementation, in the patterning method of the quantum dot layer provided in the embodiments of this disclosure, while the first photosensitive group of the first ligand in the target region undergoes bond breaking under the initiation of the photoinitiator, the method further includes: the second photosensitive group of the second ligand in the target region undergoes a crosslinking reaction, so that the quantum dot material film in the target region is insoluble in the first solvent.

[0030] Accordingly, this disclosure also provides a quantum dot light-emitting device, including an anode, a quantum dot layer, and a cathode stacked together. The quantum dot layer includes a quantum dot body and a first unit connected to the surface of the quantum dot body. The first unit includes the first coordinating group and the first dissolving group.

[0031] Accordingly, this disclosure also provides a quantum dot light-emitting device, including a light-emitting structure and a quantum dot layer located on the light-emitting side of the light-emitting structure. The quantum dot layer includes a quantum dot body and a first unit connected to the surface of the quantum dot body. The first unit includes the first coordinating group and the first dissolving group.

[0032] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the structure of the quantum dot layer includes at least one of the following: in, Represents the quantum dot entity, where n is any integer from 1 to 5.

[0033] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the quantum dot layer further includes a cross-linked network ligand connected to the surface of the quantum dot body.

[0034] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the structure of the quantum dot layer includes at least one of the following: in, Represents the quantum dot entity, where n is any integer from 1 to 5.

[0035] Accordingly, this disclosure also provides a display device, including the quantum dot light-emitting device described above in this disclosure. Attached Figure Description

[0036] Figure 1 shows the UV-Vis absorption spectra of three quantum dot material solutions before ligand exchange: red (R), green (G), and blue (B). The solvent is the organic solvent octane.

[0037] Figure 2 shows the UV-Vis absorption spectra of red (R), green (G), and blue (B) quantum dot material solutions after ligand exchange;

[0038] Figure 3 is a schematic flowchart of a quantum dot layer patterning method provided in an embodiment of this disclosure;

[0039] Figures 4A-4I are schematic diagrams of the structures corresponding to each step in fabricating the quantum dot layer;

[0040] Figure 5 is a top view of the quantum dot layer provided in an embodiment of this disclosure;

[0041] Figure 6 is a schematic diagram of the structure of a quantum dot light-emitting device provided in an embodiment of this disclosure;

[0042] Figure 7 is a schematic diagram of the structure of another quantum dot light-emitting device provided in an embodiment of this disclosure;

[0043] Figure 8 is a schematic diagram of the structure of another quantum dot light-emitting device provided in the embodiments of this disclosure. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Furthermore, the embodiments and features in the embodiments of this disclosure can be combined with each other without conflict. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0045] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "comprising" or "including," and similar terms as used in this disclosure, mean that an element or object preceding the term encompasses the elements or objects listed following the term and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Terms such as "inner," "outer," "upper," and "lower" are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0046] It should be noted that the dimensions and shapes of the figures in the accompanying drawings do not reflect actual proportions and are intended only to illustrate the content of this disclosure. Furthermore, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0047] Currently, using quantum dots for patterning to achieve high-resolution QLED fabrication has become an important topic. However, in the current process of directly patterning quantum dots, quantum dot residue is easily generated after the development process, causing color mixing problems in full-color quantum dot displays, reducing the color purity of QLED devices, and ultimately leading to a reduction in the color gamut of QLED display panels.

[0048] This disclosure provides a quantum dot material, including a quantum dot body and a first ligand attached to the surface of the quantum dot body. The first ligand includes a first coordinating group, a first dissolving group, and a first photosensitive group. The first coordinating group is coordinated with the quantum dot body, and the first dissolving group is connected between the first coordinating group and the first photosensitive group. The first photosensitive group is configured to undergo bond breaking under light irradiation, causing the first ligand to decompose into a first unit containing the first coordinating group and the first dissolving group. The first unit and the first ligand have different solubilities.

[0049] The quantum dot material provided in this embodiment can be used to fabricate a quantum dot layer, which can serve as the light-emitting layer of a QLED. After forming a quantum dot film using a solution of the quantum dot material, a target area of ​​the quantum dot film can be irradiated with light of a preset wavelength. Under illumination, the first photosensitive group in the target area undergoes bond breaking to form a first unit with different solubility than the first ligand. Therefore, the quantum dot material that is not irradiated by light has a higher solubility in the initial solvent, while the quantum dot material in the irradiated target area has a lower solubility in the initial solvent. During development, a patterned quantum dot layer is formed in the target area, and the other unirradiated quantum dot materials are developed away, thus achieving the requirement of high-resolution patterning of quantum dots.

[0050] Optionally, the preset wavelength of light can be ultraviolet (UV) light.

[0051] Currently, in the synthesis of quantum dot materials, the surface ligands are generally conventional ligands such as oleic acid, which have no or very weak photoresponsive properties. The solvents are typically toluene, octane, hexane, heptane, dichloromethane, etc., which are prohibited in mass production lines. The purpose of this disclosure is to provide a quantum dot material with a photosensitive ligand. On the one hand, this photosensitive ligand renders the quantum dot material insoluble in the original solvent after light irradiation. On the other hand, the original solvent for the photosensitive ligand is a green, pollution-free, and non-toxic solvent, such as PGMEA (propylene glycol methyl ether acetate) or similar solvents. This requires the first ligand to have high solubility in PGMEA before light irradiation and to be insoluble in PGMEA after light irradiation.

[0052] In some embodiments, the first photosensitive group in the quantum dot material provided in this disclosure may include, but is not limited to, a tert-butoxycarbonyl group, wherein the structural formula of the tert-butoxycarbonyl group is as follows: The tert-butyloxycarbonyl group can undergo a bond-breaking reaction under light irradiation, which changes the solubility of the first ligand in PGMEA before and after bond breaking.

[0053] In some embodiments, the first dissolving group in the quantum dot material provided in this disclosure has the following structure:

[0054] Where n is any integer from 1 to 5, and * represents the connection site.

[0055] Specifically, the first solubilizing group is a PEG (polyethylene glycol) segment structure, which can increase the solubility of the first ligand in PGMEA. Furthermore, the n value should not be too large, as an excessively large n value will result in an overly long carbon chain of the first ligand, which is detrimental to the charge transport and recombination performance of the QLED light-emitting layer.

[0056] In some embodiments, in the quantum dot materials provided in the present disclosure, the first coordinating group may include, but is not limited to, at least one of amino, carboxylic acid, mercapto, phosphino, phosphoxy, or dithiol.

[0057] In some embodiments, in the quantum dot materials provided in this disclosure, the first ligand further includes a first linking group located between the first photosensitive group and the first dissolving group, wherein the first linking group comprises an alkylene group having 1-6 carbon atoms. Optionally, the structure of the first ligand is as follows: The first coordinating group is an amino group, the first dissolving group is a PEG segment structure, the first linking group is two alkylene groups, and the first photosensitive group is a tert-butyloxycarbonyl group; for example, when n=2, the structure of the first ligand is... For example, when n=3, the structure of the first ligand is:

[0058] In some embodiments, in the quantum dot materials provided in this disclosure, the first ligand further includes a second linking group located between the first coordinating group and the first dissolving group, the second linking group comprising an alkylene group having 1-6 carbon atoms. Optionally, the structure of the first ligand is as follows: The first coordinating group is an amino group, the second linking group consists of two alkylene groups, the first dissolving group is a PEG segment structure, and the first photosensitive group is a tert-butyloxycarbonyl group; for example, when n=2, the structure of the first ligand is...

[0059] In some embodiments, in the quantum dot material provided in this disclosure, the first ligand further includes an imino group located between the first photosensitive group and the first dissolving group, for example, the structure of the first ligand is as follows: The first coordinating group is an amino group, the first dissolving group is a PEG segment structure, and the first photosensitive group is a tert-butyloxycarbonyl group.

[0060] In some embodiments, in the quantum dot materials provided in this disclosure, the first ligand further includes a second linking group located between the first coordinating group and the first dissolving group, the second linking group comprising an alkylene group having 1-6 carbon atoms. Optionally, the structure of the first ligand is as follows: The first coordinating group is an amino group, the second linking group consists of two alkylene groups, the first dissolving group is a PEG segment structure, and the first photosensitizing group is a tert-butyloxycarbonyl group; for example, when n=4, the structure of the first ligand is...

[0061] Specifically, for example, the structure of the first ligand is Quantum dot body adopts The structure of the quantum dot material including the first ligand is then expressed as follows: PAG can be a photoinitiator that initiates the cleavage of the tert-butyloxycarbonyl group under light irradiation, with the following structure: PAG is soluble in PGMEA, and other photoinitiators soluble in PGMEA can also be used. Under light irradiation (hv), PAG can initiate the bond-breaking reaction of the tert-butyloxycarbonyl group: Formed after bond breakage (Unit 1) Insoluble in the solvent PGMEA, and not exposed to light after PGMEA development. The quantum dot material with (first ligand) capping is removed by light, and the area exposed to light becomes... End-capped quantum dot materials enable quantum dot layer patterning. Therefore, under illumination, the first ligand, PAG, induces the breaking of tert-butyloxycarbonyl bonds, altering the solubility of the quantum dot material in PGMEA and achieving quantum dot patterning.

[0062] In some embodiments, the quantum dot material provided in this disclosure further includes a second ligand connected to the surface of the quantum dot body. The second ligand includes a second coordinating group, a second dissolving group, and a second photosensitive group. The second coordinating group is coordinated with the quantum dot body, and the second dissolving group is connected between the second coordinating group and the second photosensitive group. The second photosensitive group is configured to undergo a cross-linking reaction under light irradiation to form a cross-linked network ligand. The cross-linked network ligand has the same solubility as the first unit.

[0063] When the target area is exposed, the second photosensitive group in the target area undergoes a cross-linking reaction under light to form a cross-linked network ligand with the same solubility as the first unit. In this embodiment, the quantum dot material uses dual photosensitive ligands. Under light, the first ligand undergoes bond breaking, and the second ligand undergoes cross-linking. Both of these reduce the solubility of the quantum dot material after light exposure, thus greatly improving the difference in solubility between the exposed and unexposed areas of the quantum dot material before and after light exposure. Therefore, better quantum dot layer retention can be achieved, effectively solving the problem of quantum dot layer residue during the development process and improving the performance of quantum dot light-emitting devices prepared by photolithography.

[0064] The purpose of this disclosure is to provide a quantum dot material with two photosensitive ligands. On the one hand, both photosensitive ligands make the quantum dot material insoluble in the original solvent after light irradiation. On the other hand, the original solvents of the two photosensitive ligands are green, pollution-free, and non-toxic solvents, such as PGMEA (propylene glycol methyl ether acetate) and similar solvents. This requires that the first and second ligands have high solubility in PGMEA before light irradiation and be insoluble in PGMEA after light irradiation.

[0065] In some embodiments, the second photosensitive group in the quantum dot material provided in this disclosure includes, but is not limited to, carbon-carbon double bonds. When the second photosensitive group is selected from structures containing carbon-carbon double bonds, under illumination, the carbon-carbon double bonds in the second photosensitive group can be cross-linked, causing the illuminated quantum dot material to form a cross-linked network ligand, making the illuminated quantum dot material insoluble in PGMEA, and further improving the patterning effect of the quantum dot layer.

[0066] Optionally, the second photosensitive group includes a structure having the following structure:

[0067] R1 includes alkyl groups with 1-4 carbon atoms, and * indicates a linking site.

[0068] It should be noted that the second photosensitive group can also be a structure including a saturated 3-5 membered heterocyclic group containing O or S, for example, the structure of the second photosensitive group is as follows:

[0069] In some embodiments, the second dissolving group in the quantum dot material provided in this disclosure has the following structure:

[0070] R2 includes alkylene groups with 1-3 carbon atoms, and * indicates a linking site.

[0071] In some embodiments, the second coordinating group in the quantum dot materials provided in the present disclosure includes, but is not limited to, at least one of amino, carboxylic acid, mercapto, phosphin, phosphoxy, or dithiol.

[0072] In some embodiments, the quantum dot material provided in this disclosure further includes a third linking group located between the second coordinating group and the second dissolving group, wherein the third linking group comprises an alkylene group having 1-6 carbon atoms.

[0073] Optionally, the structure of the second ligand includes, but is not limited to, (abbreviated as MMES), wherein the second coordinating group is a carboxyl group, the third linking group consists of two alkylene groups, and the second dissolving group is... The second photosensitive group is

[0074] It should be noted that the second ligand provided in the embodiments of this disclosure is not limited to MMES, but may also be a derivative of MMES dissolved in PGMEA or other structures that can undergo photocrosslinking reaction.

[0075] Specifically, for example, the structure of the first ligand is The structure of the second ligand is as follows: Quantum dot body adopts The structure of a quantum dot material including a first ligand and a second ligand is then expressed as follows: The photoinitiator is PAG. Under light irradiation (hv), PAG can initiate a bond-breaking reaction on the tert-butoxycarbonyl group of the first ligand, and in the second ligand... The carbon-carbon double bonds undergo cross-linking reactions: The bond formed after the break (Unit 1) and the formed cross-linked network ligands are insoluble in the solvent PGMEA. After PGMEA development, they were not exposed to light. (first ligand) and (Second ligand)-terminated quantum dot materials are developed away, and the areas exposed to light become... Quantum dot materials with cross-linked network ligands end-capped are used to achieve quantum dot layer patterning. Therefore, under light irradiation, one of the first ligands undergoes bond breaking, and the other undergoes cross-linking, changing the solubility of the quantum dot material in PGMEA and achieving better quantum dot layer retention, thereby realizing quantum dot patterning.

[0076] It should be noted that the embodiments disclosed herein use the first ligand as... The second ligand is For example, but not limited to this.

[0077] It should be noted that the above quantum dot material surface only illustrates one first ligand and one second ligand. Of course, there can be multiple first and second ligands on the surface of a quantum dot material.

[0078] Currently, the quantum dot materials that are originally purchased or synthesized are all conventional oil-soluble ligands such as oleic acid. In order to obtain the quantum dot materials including the first ligand and the second ligand provided in the embodiments of this disclosure, we can perform ligand exchange on the purchased quantum dot materials. For example, we can replace oleic acid with the first ligand and the second ligand with photosensitive properties disclosed in this disclosure. The solvents for the original oleic acid ligand quantum dot materials are toluene, octane, hexane, heptane, dichloromethane, etc. The quantum dot materials that are replaced with the first ligand and the second ligand can be dissolved in PGMEA green solvent.

[0079] The transformation from being soluble in the organic phase to being soluble in the PGMEA before and after ligand exchange confirms the successful occurrence of the ligand exchange process. The ligand-exchanged QD no longer dissolves in the original organic solvent. Furthermore, the organic solvent was used as the precipitant for centrifugal purification of the ligand-exchanged QD.

[0080] The quantum dot material containing the original oil-soluble ligand is exchanged for the first ligand described above in this disclosure. Second ligand The specific ligand exchange process is as follows:

[0081] 1) Take 30 mg of the original oil-soluble quantum dot material of three colors (e.g., red, green, and blue), and evaporate the solvent (e.g., octane) to dryness for later use.

[0082] 2) Add the first ligand and PGMEA solvent respectively, and stir for 30 min.

[0083] 3) Use octane as a centrifugal purification agent to wash the quantum dot material after the first ligand exchange, and discard the supernatant to obtain the quantum dot material including the first ligand provided in this disclosure.

[0084] 4) Dissolve the quantum dot material from 3) in PGMEA solvent, add the second ligand, and stir for 30 min.

[0085] 5) Octane was used as a centrifugal purification agent to wash the quantum dot material after the second ligand exchange.

[0086] 6) Discard the supernatant from step 5), and vacuum the quantum dot material in the centrifuge tube for 30 minutes to obtain the quantum dot material including the first ligand and the second ligand provided in this disclosure. Disperse the quantum dot material in PGMEA solvent to dissolve and store it in the dark.

[0087] Specifically, before and after the ligand exchange, the solubility of the quantum dot material changed from oil-soluble to PGMEA-soluble, and the exchanged quantum dot material precipitated in the original octane solvent, confirming the occurrence of the ligand exchange process.

[0088] To further confirm the occurrence of ligand exchange, Figures 1 and 2 are provided. Figure 1 shows the UV-Vis absorption spectra of red (R), green (G), and blue (B) quantum dot material solutions before ligand exchange, with octane as the solvent. Figure 2 shows the UV-Vis absorption spectra of the same three quantum dot material solutions after ligand exchange, with PGMEA as the solvent. The original quantum dot material was an oleic acid-terminated octane solution, and the quantum dot material after ligand exchange was the first ligand. Second ligand End-capped PGMEA solution. As can be seen from the absorption spectra in Figures 1 and 2, on the one hand, the solvent in these two absorption spectra has changed from octane to PGMEA after ligand exchange, indicating that ligand exchange has occurred; on the other hand, the peak positions and peak shapes of the absorption spectra remain unchanged before and after ligand exchange, which also indicates that the quantum dot material does not exhibit negative behaviors such as aggregation during and after ligand exchange.

[0089] Specifically, the quantum dot body can be a semiconductor nanocrystal and can have various shapes such as spherical, conical, multi-armed, and / or cubic nanoparticles, nanotubes, nanowires, nanofibers, nanoplate particles, quantum rods, or quantum sheets. Here, the quantum rod can be a quantum dot with an aspect 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 less than or equal to about 50, less than or equal to about 30, or less than or equal to about 20.

[0090] The quantum dot body may have, for example, a particle diameter of 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 (for non-spherical shapes, the average maximum particle length).

[0091] The band gap of a quantum dot can be controlled according to its size and composition, and thus the emission wavelength can be controlled. For example, as the size of the quantum dot increases, it can have a narrow band gap and thus be configured to emit light in a relatively long wavelength region, while as the size of the quantum dot decreases, it can have a wide band gap and thus be configured to emit light in a relatively short wavelength region. For example, the quantum dot can be configured to emit light in a predetermined wavelength region of the visible light region, depending on its size and / or composition. For example, the quantum dot can be configured to emit blue light, red light, or green light, and the blue light can have a peak emission wavelength (λmax) in, for example, from about 430 nm to about 480 nm, the red light can have a peak emission wavelength (λmax) in, for example, from about 600 nm to about 650 nm, and the green light can have a peak emission wavelength (λmax) in, for example, from about 520 nm to about 560 nm.

[0092] For example, the average particle size of the quantum dots configured to emit blue light may be, for example, less than or equal to about 4.5 nm, and for example, 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 this range, for example, the average particle size of the quantum dots may be from about 2.0 nm to about 4.5 nm, for example, from about 2.0 nm to about 4.3 nm, from about 2.0 nm to about 4.2 nm, from about 2.0 nm to about 4.1 nm, or from about 2.0 nm to about 4.0 nm.

[0093] The quantum dot body may have a quantum yield of, for example, greater than or equal to about 10%, greater than or equal to about 20%, greater than or equal to about 30%, greater than or equal to about 50%, greater than or equal to about 60%, greater than or equal to about 70%, or greater than or equal to about 90%.

[0094] The quantum dot body may have a relatively narrow half-width (FWHM). Here, FWHM is the width corresponding to half the wavelength of the peak absorption point, and when the FWHM is narrow, it can be configured to emit light in a narrower wavelength region and achieve higher color purity. The quantum dots may have a FWHM of, for example, less than or equal to about 50 nm, less than or equal to about 49 nm, less than or equal to about 48 nm, less than or equal to about 47 nm, less than or equal to about 46 nm, less than or equal to about 45 nm, less than or equal to about 44 nm, less than or equal to about 43 nm, less than or equal to about 42 nm, less than or equal to about 41 nm, less than or equal to about 40 nm, less than or equal to about 39 nm, less than or equal to about 38 nm, less than or equal to about 37 nm, less than or equal to about 36 nm, less than or equal to about 35 nm, less than or equal to about 34 nm, less than or equal to about 33 nm, less than or equal to about 32 nm, less than or equal to about 31 nm, less than or equal to about 30 nm, less than or equal to about 29 nm, or less than or equal to about 28 nm. Within the range, it may have, for example, an FWHM of about 2nm to about 49nm, about 2nm to about 48nm, about 2nm to about 47nm, about 2nm to about 46nm, about 2nm to about 45nm, about 2nm to about 44nm, about 2nm to about 43nm, about 2nm to about 42nm, about 2nm to about 41nm, about 2nm to about 40nm, about 2nm to about 39nm, about 2nm to about 38nm, about 2nm to about 37nm, about 2nm to about 36nm, about 2nm to about 35nm, about 2nm to about 34nm, about 2nm to about 33nm, about 2nm to about 32nm, about 2nm to about 31nm, about 2nm to about 30nm, about 2nm to about 29nm, or about 2nm to about 28nm.

[0095] For example, the quantum dot bulk may include group II-VI semiconductor compounds, group III-V semiconductor compounds, group IV-VI semiconductor compounds, group IV semiconductors, group I-III-VI semiconductor compounds, group I-II-IV-VI semiconductor compounds, group II-III-V semiconductor compounds, or combinations thereof. The group II-VI semiconductor compounds may be selected, for example, from: binary compounds such as CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, or mixtures thereof; ternary compounds such as CdSeS, CdSeTe, etc. CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, or mixtures thereof; and quaternary compounds such as HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or mixtures thereof, but not limited thereto. The III-V semiconductor compounds may be selected, for example, from: binary compounds such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or mixtures thereof; ternary compounds such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, or mixtures thereof; and quaternary compounds such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or mixtures thereof, but are not limited thereto. The IV-VI group semiconductor compounds may be selected, for example, from: binary compounds such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, or mixtures thereof; ternary compounds such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or mixtures thereof; and quaternary compounds such as SnPbSSe, SnPbSeTe, SnPbSTe, or mixtures thereof, but are not limited thereto.The group IV semiconductors may be selected, for example, from: elemental (monological) semiconductors such as Si, Ge, or mixtures thereof; and binary semiconductor compounds such as SiC, SiGe, and mixtures thereof, but are not limited thereto. The group I-III-VI semiconductor compounds may be, for example, CuInSe2, CuInS2, CuInGaSe, CuInGaS, or mixtures thereof, but are not limited thereto. The group I-II-IV-VI semiconductor compounds may be, for example, CuZnSnSe, CuZnSnS, or mixtures thereof, but are not limited thereto. The group II-III-V semiconductor compounds may include, for example, InZnP, but are not limited thereto.

[0096] The quantum dot bulk can have a substantially uniform concentration or locally different concentration distribution, including the elemental semiconductor, the binary semiconductor compound, the ternary semiconductor compound, or the quaternary semiconductor compound.

[0097] For example, the quantum dot body may include cadmium-free (Cd) quantum dots. Cadmium-free quantum dots are quantum dots that do not contain cadmium (Cd). Cadmium (Cd) can cause serious environmental / health problems and is a restricted element under the Restriction of Hazardous Substances Directive (RoHS) in many countries, and therefore cadmium-free quantum dots can be used effectively.

[0098] As an example, the quantum dot body may be a semiconductor compound comprising at least one of zinc (Zn), tellurium (Te), and selenium (Se). For example, the quantum dot may be a Zn-Te semiconductor compound, a Zn-Se semiconductor compound, and / or a Zn-Te-Se semiconductor compound. For example, the amount of tellurium (Te) in the Zn-Te-Se semiconductor compound may be less than the amount of selenium (Se). The semiconductor compound may have a peak emission wavelength (λ maximum) in a wavelength region of less than or equal to about 480 nm, for example, about 430 nm to about 480 nm, and may be configured to emit blue light.

[0099] For example, the quantum dot bulk may be a semiconductor compound comprising at least one of indium (In), zinc (Zn), and phosphorus (P). For example, the quantum dot may be an In-P semiconductor compound and / or 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 maximum) in a wavelength region less than about 700 nm, for example, from about 600 nm to about 650 nm, and may be configured to emit red light.

[0100] The quantum dot body may have a core-shell structure, with one quantum dot surrounding another. For example, the core and shell of the quantum dot may have an interface, and at least one element of the core or the shell may have a concentration gradient at the interface, wherein the concentration of the element in the shell decreases toward the core. For example, the material composition of the shell of the quantum dot has a higher band gap than the material composition of the core of the quantum dot, and thereby the quantum dot may exhibit a quantum confinement effect.

[0101] The quantum dot body may have a quantum dot core and a multi-layered quantum dot shell surrounding the core. Here, the multi-layered shell has at least two shells, wherein each shell may be a single composition, an alloy, and / or have a concentration gradient.

[0102] For example, the shells of a multilayered structure that are farther from the core may have a higher band gap than the shells closer to the core, and thus the quantum dot may exhibit a quantum confinement effect.

[0103] For example, a quantum dot having a core-shell structure may include, for example, a core comprising a first semiconductor compound comprising zinc (Zn) and at least one of tellurium (Te) and selenium (Se); and a shell disposed on at least a portion of the core and having a composition different from that of the core, comprising a second semiconductor compound.

[0104] For example, the first semiconductor compound may be a Zn-Te-Se based semiconductor compound comprising zinc (Zn), tellurium (Te) and selenium (Se), for example, a Zn-Se based semiconductor compound comprising a small amount of tellurium (Te), for example, a semiconductor compound represented by ZnTexSe1-x, wherein x is greater than about 0 and less than or equal to 0.05.

[0105] 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, less than or equal to about 0.049, less than or equal to about 0.048, less than or equal to about 0.047, less than or equal to about 0.045, less than or equal to about 0.044, less than or equal to about 0.043, less than or equal to about 0.042, less than or equal to about 0.041, less than or equal to about 0.04, less than or equal to about 0.039, less than or equal to about 0.035, less than or equal to about 0.03, less than or equal to about 0.00, or less than or equal to about 0.00. 29. Less than or equal to about 0.025, Less than or equal to about 0.024, Less than or equal to about 0.023, Less than or equal to about 0.022, Less than or equal to about 0.021, Less than or equal to about 0.02, Less than or equal to about 0.019, Less than or equal to about 0.018, Less than or equal to about 0.017, Less than or equal to about 0.016, Less than or equal to about 0.015, Less than or equal to about 0.014, Less than or equal to about 0.013, Less than or equal to about 0.012, Less than or equal to about 0.011, or Less than or equal to about 0.01. 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, less than or equal to about 0.019, less than or equal to about 0.018, less than or equal to about 0.017, less than or equal to about 0.016, less than or equal to about 0.015, less than or equal to about 0.014, less than or equal to about 0.013, less than or equal to about 0.012, less than or equal to about 0.011, or less than or equal to about 0.010.

[0106] The second semiconductor compound may include, for example, group II-VI semiconductor compounds, group III-V semiconductor compounds, group IV-VI semiconductor compounds, group IV semiconductors, group I-III-VI semiconductor compounds, group I-II-IV-VI semiconductor compounds, group II-III-V semiconductor compounds, or combinations thereof. Examples of the group II-VI semiconductor compounds, group III-V semiconductor compounds, group IV-VI semiconductor compounds, group IV semiconductors, group I-III-VI semiconductor compounds, group I-II-IV-VI semiconductor compounds, and group II-III-V semiconductor compounds are the same as those described above.

[0107] 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 combinations thereof. For example, the shell may include at least one inner shell disposed near the core and an outermost shell disposed at the outermost edge of the quantum dot. The inner shell may include ZnSeS, ZnSe, or combinations thereof, and the outermost shell may include ZnS. For example, the shell may have a concentration gradient of components, and the amount of, for example, sulfur (S) may increase as it leaves the core.

[0108] For example, a quantum dot having a core-shell structure may include: a core comprising a third semiconductor compound comprising at least one of indium (In), zinc (Zn), and phosphorus (P); and a shell disposed on at least a portion of the core and comprising a fourth semiconductor compound having a composition different from that of the core.

[0109] In the In-Zn-P based third semiconductor compound, the molar ratio of zinc (Zn) to indium (In) can be greater than or equal to about 25. For example, in the In-Zn-P based third semiconductor compound, the molar ratio of zinc (Zn) to indium (In) can 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 In-Zn-P based third semiconductor compound, the molar ratio of zinc (Zn) to indium (In) can 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.

[0110] The fourth semiconductor compound may include, for example, group II-VI semiconductor compounds, group III-V semiconductor compounds, group IV-VI semiconductor compounds, group IV semiconductors, group I-III-VI semiconductor compounds, group I-II-IV-VI semiconductor compounds, group II-III-V semiconductor compounds, or combinations thereof. Examples of the group II-VI semiconductor compounds, group III-V semiconductor compounds, group IV-VI semiconductor compounds, group IV semiconductors, group I-III-VI semiconductor compounds, group I-II-IV-VI semiconductor compounds, and group II-III-V semiconductor compounds are the same as those described above.

[0111] For example, the fourth semiconductor compound may include zinc (Zn) and sulfur (S), and optionally selenium (Se). For example, the shell may include ZnSeS, ZnSe, ZnS, or combinations thereof. For example, the shell may include at least one inner shell disposed near the core and an outermost shell disposed at the outermost edge 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.

[0112] The emitting layer may have a thickness of, for example, from about 5 nm to about 200 nm, within the range of, for example, from about 10 nm to about 150 nm, for example, from about 10 nm to about 100 nm, for example, from about 10 nm to about 50 nm. The quantum dot QD contained in the emitting layer EML can be laminated into one or more layers, for example, two layers. However, embodiments of the present disclosure are not limited thereto, and the quantum dot QD can be laminated into one to ten layers. Depending on the type (or kind) of quantum dot QD used and the desired emission wavelength of the light, the quantum dot QD can be laminated into any suitable number of layers.

[0113] Quantum dot bulks can have relatively deep HOMO levels, for example, HOMO levels greater than or equal to about 5.4 eV, and within the 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 the stated range, the HOMO energy levels of the quantum dot layer 13 can be, for example, about 5.4 eV to about 7.0 eV, for example, about 5.4 eV to about 6.8 eV, for example, about 5.4 eV to about 6.7 eV, for example, about 5.4 eV to about 6.5 eV, for example, about 5.4 eV to about 6.3 eV, for example, about 5.4 eV to about 6.2 eV, for example, about 5.4 eV to about 6.1 eV, and within the stated range, for example, about 5.5 eV to about 7.0 eV, for example, about 5.5 eV to about 6.8 eV, for example, about 5.5 eV to about 6.7 eV, for example, about 5.5 eV to about 6.5 eV, for example, about 5.5 eV to about 6.3 eV, for example, about 5.5 eV to about 6.2 eV, for example, about 5.5 eV to about 6.1 eV, for example, about 5.5 eV to about 7.0 eV, for example, about 5.6 eV to about 6.8 eV, for example, about 5.6 eV to about 6.7 eV, for example, about 5.6 eV to about 6.5 eV, for example, about 5.6 eV to about 6.3 eV, for example, about 5.6 eV to about 6.2 eV, for example, about 5 From 0.6 eV to about 6.1 eV, within the range of, for example, from about 5.7 eV to about 7.0 eV, for example, from about 5.7 eV to about 6.8 eV, for example, from about 5.7 eV to about 6.7 eV, for example, from about 5.7 eV to about 6.5 eV, for example, from about 5.7 eV to about 6.3 eV, for example, from about 5.7 eV to about 6.2 eV, for example, from about 5.7 eV to about 6.1 eV, within the range of, for example, from about 5.8 eV to about 7.0 eV, for example, from about 5.8 eV to about 6.8 eV, for example, from about 5.8 eV. eV to 6.7 eV, for example, about 5.8 eV to 6.5 eV, for example, about 5.8 eV to 6.3 eV, for example, about 5.8 eV to 6.2 eV, for example, about 5.8 eV to 6.1 eV, within the range of, for example, about 6.0 eV to 7.0 eV, for example, about 6.0 eV to 6.8 eV, for example, about 6.0 eV to 6.7 eV, for example, about 6.0 eV to 6.5 eV, for example, about 6.0 eV to 6.3 eV, for example, about 6.0 eV to 6.2 eV.

[0114] The quantum dot bulk may have relatively shallow LUMO energy levels, for example, less than or equal to about 3.7 eV, and within the range of, for example, less than or equal to about 3.6 eV, less than or equal to about 3.5 eV, less than or equal to about 3.4 eV, less than or equal to about 3.3 eV, less than or equal to about 3.2 eV, or less than or equal to about 3.0 eV. Within the range of, the LUMO energy levels of the quantum dot layer 13 may 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, or about 2. 8 eV 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.

[0115] The quantum dot body may have a band gap of about 1.7 eV to about 2.3 eV or about 2.4 eV to about 2.9 eV. Within these ranges, for example, the quantum dot layer 13 may have a band gap of about 1.8 eV to about 2.2 eV or about 2.4 eV to about 2.8 eV, and within these ranges, for example, about 1.9 eV to about 2.1 eV or about 2.4 eV to about 2.7 eV.

[0116] Based on the same inventive concept, this disclosure also provides a method for patterning quantum dot layers, as shown in Figure 3, including:

[0117] S301. Dissolve the quantum dot material and photoinitiator provided in the embodiments of this disclosure in a first solvent to obtain a mixed solution, and spin-coat the mixed solution onto one side of a substrate to form a quantum dot material film;

[0118] S302. The target area of ​​the quantum dot material film is exposed to light of a preset wavelength. The first photosensitive group of the first ligand in the target area undergoes bond breaking under the initiation of the photoinitiator, making the quantum dot material film in the target area insoluble in the first solvent.

[0119] S303. The exposed quantum dot material film is developed using a first solvent to form a patterned quantum dot layer in the target area.

[0120] In some embodiments, in the patterning method of the quantum dot layer provided in the present disclosure, if the quantum dot material further includes the second ligand, the second photosensitive group of the second ligand in the exposed target area undergoes a cross-linking reaction simultaneously, making the quantum dot material film in the target area even more insoluble in the first solvent.

[0121] The following describes the patterning method of quantum dot layers provided in this disclosure, taking a quantum dot material including a first ligand and a second ligand as an example.

[0122] To achieve full-color display, the quantum dot layer generally includes patterned quantum dot materials of different colors. This disclosure takes an example of a quantum dot layer including a first quantum dot layer, a second quantum dot layer, and a third quantum dot layer, and describes in detail the patterning method of the quantum dot layer provided in this disclosure with reference to the accompanying drawings.

[0123] Specifically, a first quantum dot material solution, a second quantum dot material solution, and a third quantum dot material solution of different colors are provided, wherein the quantum dot material in each color quantum dot material solution is, for example, CdSe, and the first ligand on the CdSe surface is... The second ligand is The primary solvent for each quantum dot material solution is PGMEA, and the photoinitiator is PAG.

[0124] As shown in Figure 4A, a first quantum dot material thin film 2 is formed by spin-coating a first mixed solution comprising a first quantum dot material solution and a photoinitiator onto a substrate 1.

[0125] As shown in Figure 4B, ultraviolet light (indicated by the arrow in the figure) is used to expose the first target area A1 of the first quantum dot material film 2. The first target area A1 corresponds to the area where the first quantum dot layer needs to be formed subsequently. Specifically, when the first quantum dot material film 2 is irradiated with ultraviolet light, a mask 3 can be used to block the first quantum dot material film 2. The mask 3 includes a light-transmitting area 31 and a light-blocking area 32. The light-transmitting area 31 corresponds to the first target area A1 in the first quantum dot material film 2 that receives light irradiation.

[0126] Specifically, after exposure, in the first target region A1, the first photosensitive group (tert-butyloxycarbonyl) of the first ligand undergoes bond cleavage under the initiation of the photoinitiator, and the second photosensitive group of the second ligand within the first target region A1... The carbon-carbon double bonds undergo a cross-linking reaction, and the reaction formula is as follows: This makes the first quantum dot material film 2 insoluble in PGMEA in the first target region A1.

[0127] As shown in Figure 4C, the first quantum dot material film 2 after exposure is developed using a first solvent (PGMEA). The first quantum dot material in the area of ​​the first quantum dot material film 2 that is not irradiated by ultraviolet light dissolves in PGMEA and is washed away, while the first quantum dot material in the first target area A1 undergoes bond breaking and cross-linking and does not dissolve in PGMEA, thereby forming a patterned first quantum dot layer 2' in the first target area A1.

[0128] Next, the second quantum dot material solution and the photoinitiator are mixed to form a second mixed solution. As shown in Figure 4D, the second mixed solution is coated on the substrate 1 on which the first quantum dot layer 2' is formed by spin coating to form a second quantum dot material film 4.

[0129] As shown in Figure 4E, ultraviolet light (indicated by the arrow in the figure) is used to expose the second target region A2 of the second quantum dot material film 4. The second target region A2 corresponds to the region where the second quantum dot layer needs to be formed subsequently. Specifically, when the second quantum dot material film 4 is irradiated with ultraviolet light, a mask 3 can be used to block the second quantum dot material film 4. The mask 3 includes a light-transmitting region 31 and a light-blocking region 32. The light-transmitting region 31 corresponds to the second target region A2 in the second quantum dot material film 4 that receives light irradiation.

[0130] Specifically, after exposure, in the second target region A2, the first photosensitive group (tert-butyloxycarbonyl) of the first ligand undergoes bond cleavage under the initiation of the photoinitiator, and the second photosensitive group of the second ligand within the second target region A2... The carbon-carbon double bonds undergo a cross-linking reaction, and the reaction formula is as follows: This makes the second quantum dot material film 4 insoluble in PGMEA in the second target region A2.

[0131] As shown in Figure 4F, the exposed second quantum dot material film 4 is developed using a first solvent (PGMEA). The second quantum dot material in the area of ​​the second quantum dot material film 4 that is not irradiated by ultraviolet light dissolves in PGMEA and is washed away, while the first quantum dot material in the second target area A2 undergoes bond breaking and cross-linking and does not dissolve in PGMEA, thereby forming a patterned second quantum dot layer 4' in the second target area A2.

[0132] Finally, the third quantum dot material solution and the photoinitiator are mixed to form a third mixed solution. As shown in Figure 4G, the third mixed solution is coated on the substrate 1 on which the second quantum dot layer 4' is formed by spin coating to form a third quantum dot material film 5.

[0133] As shown in Figure 4H, ultraviolet light (indicated by the arrow in the figure) is used to expose the third target region A3 of the third quantum dot material film 5. The third target region A3 corresponds to the region where the third quantum dot layer needs to be formed subsequently. Specifically, when the third quantum dot material film 5 is irradiated with ultraviolet light, a mask 3 can be used to block the third quantum dot material film 5. The mask 3 includes a light-transmitting region 31 and a light-blocking region 32. The light-transmitting region 31 corresponds to the third target region A3 in the third quantum dot material film 5 that receives light irradiation.

[0134] Specifically, after exposure, in the third target region A3, the first photosensitive group (tert-butyloxycarbonyl) of the first ligand undergoes bond cleavage under the initiation of the photoinitiator, and the second photosensitive group of the second ligand within the third target region A3... The carbon-carbon double bonds undergo a cross-linking reaction, and the reaction formula is as follows: This makes the third quantum dot material film 5 in the third target region A3 insoluble in PGMEA.

[0135] As shown in Figure 4I, the exposed third quantum dot material film 5 is developed using a first solvent (PGMEA). The third quantum dot material in the area of ​​the third quantum dot material film 5 that is not irradiated by ultraviolet light dissolves in PGMEA and is washed away, while the first quantum dot material in the third target area A3 undergoes bond breaking and cross-linking and does not dissolve in PGMEA, thereby forming a patterned third quantum dot layer 5' in the third target area A3.

[0136] As shown in Figure 5, which is a top view of the quantum dot layer, the quantum dot layer includes a first quantum dot layer 2', a second quantum dot layer 4', and a third quantum dot layer 5'.

[0137] In specific implementation, the colors of the light emitted by the first quantum dot layer, the second quantum dot layer, and the third quantum dot layer in this embodiment are red, green, and blue, respectively. Thus, this embodiment completes the patterning process of full-color quantum dots using the above patterning method. This embodiment does not require inkjet printing to complete the patterning of the quantum dot layer, enabling the formation of high-resolution, high-performance quantum dot layers.

[0138] In one possible implementation, the fabrication of the first quantum dot layer, the second quantum dot layer, and the third quantum dot layer provided in this disclosure can be achieved by irradiating the first quantum dot retention region, the second quantum dot retention region, and the third quantum dot retention region with the same wavelength of ultraviolet light. Alternatively, H-line light can be used to irradiate the first target region to form a first quantum dot layer emitting red light, with the wavelength of the H-line being 405 nm; I-line light can be used to irradiate the second target region to form a second quantum dot layer emitting green light, with the wavelength of the I-line being 365 nm; and G-line light can be used to irradiate the third target region to form a third quantum dot layer emitting blue light, with the wavelength of the G-line being 436 nm.

[0139] In specific implementations, the quantum dot layer fabricated using the patterning method for quantum dot layers provided in the embodiments of this disclosure can not only serve as the light-emitting layer in QLED devices, but also as the light conversion film layer in the backlight of a liquid crystal display, the color filter layer in a liquid crystal display, the color filter layer in a white OLED device with a color filter layer, and so on.

[0140] Based on the same inventive concept, this disclosure also provides a quantum dot light-emitting device, as shown in Figures 6 and 7, which includes an anode 6, a quantum dot layer 10, and a cathode 7 stacked together. The quantum dot layer 10 includes a first quantum dot layer 2', a second quantum dot layer 4', and a third quantum dot layer 5' fabricated above. The first quantum dot layer 2', the second quantum dot layer 4', and the third quantum dot layer 5' each include a quantum dot body and a first unit connected to the surface of the quantum dot body. The first unit is the first unit in the quantum dot material provided in this disclosure, that is, the first unit includes a first coordinating group and a first dissolving group.

[0141] Based on the same inventive concept, this disclosure also provides a quantum dot light-emitting device, as shown in FIG8, including a light-emitting structure 20 and a quantum dot layer 10 located on the light-emitting side of the light-emitting structure 20. The quantum dot layer 10 includes a first quantum dot layer 2', a second quantum dot layer 4' and a third quantum dot layer 5' fabricated above. The first quantum dot layer 2', the second quantum dot layer 4' and the third quantum dot layer 5' each include a quantum dot body and a first unit connected to the surface of the quantum dot body. The first unit is the first unit in the quantum dot material provided in this disclosure embodiment, that is, the first unit includes a first coordinating group and a first dissolving group.

[0142] Specifically, as shown in Figure 8, the light-emitting structure 20 may include multiple light-emitting units, and the light-emitting color of the light-emitting units may be white, blue, etc.

[0143] Specifically, as shown in Figure 8, the quantum dot layer 10 in this quantum dot light-emitting device is a color conversion layer. For example, the light emitted by the light-emitting structure 20 is white light, and by using the quantum dot layer 10, the white light can be converted into red light, green light, and blue light, etc.

[0144] Optionally, as shown in Figure 8, the quantum dot light-emitting device can be a backlight for a liquid crystal display, or a white OLED with a color filter, etc.

[0145] Optionally, as shown in Figures 6-8, the structure of the quantum dot layer 10 includes at least one of the following: in, Represents the quantum dot entity, where n is any integer from 1 to 5.

[0146] In some embodiments, as shown in Figures 6-8, the quantum dot layer 10 further includes a cross-linked network ligand connected to the surface of the quantum dot body. The cross-linked network ligand is the cross-linked network ligand in the quantum dot material provided in the embodiments of this disclosure.

[0147] Optionally, as shown in Figures 6-8, the structure of the quantum dot layer 10 may further include at least one of the following: in, Represents the quantum dot entity, where n is any integer from 1 to 5.

[0148] Optionally, as shown in Figures 6 and 7, the quantum dot light-emitting device further includes: a hole injection layer 8 located between the anode 6 and the quantum dot layer 10, a hole transport layer 9 located between the hole injection layer 8 and the quantum dot layer 10, and an electron transport layer 11 located between the quantum dot layer 10 and the cathode 7.

[0149] Specifically, the quantum dot light-emitting device shown in Figure 6 is an upright structure, and the quantum dot light-emitting device shown in Figure 7 is an inverted structure. In the upright structure, an anode 6, a hole injection layer 8, a hole transport layer 9, a quantum dot layer 10, an electron transport layer 11, and a cathode 7 are sequentially formed on the substrate 1. In the inverted structure, a cathode 7, an electron transport layer 11, a quantum dot layer 10, a hole transport layer 9, a hole injection layer 8, and an anode 6 are sequentially formed on the substrate 1.

[0150] As shown in Figure 7, the electron transport layer 11 can be a photoresponsive layer. For example, the electron transport layer includes ZnO and the first and second ligands connected to the ZnO surface. The ligands on the initial ZnO surface are generally hydroxyl, carboxyl, etc. The first and second ligands can also be formed on the ZnO surface by ligand exchange. In this way, when the quantum dot layer is formed by photolithography, the electron transport layer 11 can act as a sacrificial layer, so that the quantum dot material is fully developed and quantum dot residue is prevented.

[0151] The light emission mode of the quantum dot light-emitting device provided in the embodiments of this disclosure can be bottom light emission or top light emission.

[0152] The following describes the fabrication method of a quantum dot light-emitting device, using the quantum dot light-emitting device shown in Figure 6 as an example. The specific steps include:

[0153] (1) Clean the glass substrate, then deposit gate metal (material is Mo, thickness can be 200nm) and pattern it to form gate, gate line, etc.; then deposit gate insulating layer (material is SiO2, thickness can be 150nm); then deposit semiconductor material (material is IGZO, thickness can be 40nm) and pattern it to form active layer; then deposit source drain metal (material is Mo, thickness can be 200nm) and pattern it to form source, drain, data line, etc.; then deposit passivation layer (material is SiO2, thickness can be 300nm) and pattern it; then deposit anode metal (material is ITO, thickness can be 40nm) and pattern it to form anode; finally spin-coat photoresist material and photolithography and curing to form pixel boundary layer, thickness can be 1.5μm, to form TFT backplane.

[0154] (2) The surface of the TFT backplane is treated using plasma processing technology.

[0155] (3) Hole injection layer and hole transport layer are prepared sequentially on the anode by spin coating process, such as spin coating PEDOT (poly(3,4-ethylenedioxythiophene), PSS (polystyrene sulfonic acid) and TFB, etc.; the overall thickness is 50-100nm.

[0156] (4) The quantum dot layer is formed on the hole transport layer by using the steps of Figure 4A-Figure 4I above.

[0157] (5) Electron transport layer and electron injection layer are formed on quantum dot layer by spin coating or vapor deposition, such as ZnO nanoparticles.

[0158] (6) Evaporate a thin layer of cathode metal. The cathode can be an Al layer or the like, with a thickness of 500-1000 nm. After evaporation, encapsulate and cut the device to complete the fabrication of the entire quantum dot light-emitting device.

[0159] Based on the same inventive concept, this disclosure also provides a display device, including the quantum dot light-emitting device described above. The principle by which this display device solves the problem is similar to that of the aforementioned quantum dot light-emitting device; therefore, the implementation of this display device can refer to the implementation of the aforementioned quantum dot light-emitting device, and the repetitions will not be repeated here.

[0160] This disclosure provides a quantum dot material, a quantum dot layer patterning method, and related applications. The quantum dot material can be used to fabricate a quantum dot layer, which can serve as the light-emitting layer of a QLED. After forming a quantum dot film using a solution of the aforementioned quantum dot material, a target area of ​​the quantum dot film can be irradiated with light of a preset wavelength. Under illumination, the first photosensitive group in the target area undergoes bond breaking to form a first unit with a different solubility than the first ligand. Under illumination, the second photosensitive group in the target area undergoes a cross-linking reaction to form a cross-linked network ligand with the same solubility as the first unit. Therefore, the quantum dot material that is not irradiated by light has a higher solubility in the initial solvent, while the quantum dot material in the irradiated target area has a lower solubility in the initial solvent. During development, a patterned quantum dot layer is formed in the target area, and the other unirradiated quantum dot materials are developed away, thus achieving the requirement of high-resolution quantum dot patterning. Furthermore, the quantum dot material disclosed herein employs dual photosensitive ligands. Under illumination, one ligand undergoes bond breaking, while the other undergoes cross-linking. Both of these processes reduce the solubility of the quantum dot material after illumination, thereby significantly improving the difference in solubility between the exposed and unexposed areas of the quantum dot material before and after illumination. This results in better quantum dot layer retention, effectively solving the problem of quantum dot layer residue during the development process and improving the performance of quantum dot light-emitting devices fabricated by photolithography.

[0161] Although preferred embodiments of this disclosure have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this disclosure.

[0162] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this disclosure without departing from the spirit and scope of the embodiments of this disclosure. Therefore, if these modifications and variations to the embodiments of this disclosure fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include these modifications and variations.

Claims

1. A quantum dot material, wherein, The device includes a quantum dot matrix and a first ligand attached to the surface of the quantum dot matrix. The first ligand includes a first coordinating group, a first dissolving group, and a first photosensitive group. The first coordinating group is coordinated with the quantum dot matrix, and the first dissolving group is connected between the first coordinating group and the first photosensitive group. The first photosensitive group is configured to undergo bond breaking under light irradiation, causing the first ligand to decompose into a first unit containing the first coordinating group and the first dissolving group. The first unit and the first ligand have different solubilities.

2. The quantum dot material as described in claim 1, wherein, The first photosensitive group includes a tert-butoxycarbonyl group.

3. The quantum dot material as described in claim 1, wherein, The first dissolving group has the following structure: Where n is any integer from 1 to 5, and * represents the connection site.

4. The quantum dot material as described in claim 1, wherein, The first coordinating group includes at least one of amino, carboxylic acid, mercapto, phosphino, phosphoxy, or dithiol.

5. The quantum dot material according to any one of claims 1-4, wherein, The first ligand further includes a first linking group located between the first photosensitive group and the first dissolving group, wherein the first linking group comprises an alkylene group having 1-6 carbon atoms.

6. The quantum dot material according to any one of claims 1-4, wherein, The first ligand further includes an imino group located between the first photosensitive group and the first dissolving group.

7. The quantum dot material according to any one of claims 1-6, wherein, The first ligand further includes a second linking group located between the first coordinating group and the first dissolving group, the second linking group comprising an alkylene group having 1-6 carbon atoms.

8. The quantum dot material according to any one of claims 1-7, wherein, The structure of the first ligand includes at least one of the following: Where n is any integer from 1 to 5.

9. The quantum dot material according to any one of claims 1-8, wherein, It also includes a second ligand connected to the surface of the quantum dot body. The second ligand includes a second coordinating group, a second dissolving group, and a second photosensitive group. The second coordinating group is coordinated with the quantum dot body, and the second dissolving group is connected between the second coordinating group and the second photosensitive group. The second photosensitive group is configured to undergo a cross-linking reaction under the light irradiation condition to form a cross-linked network ligand. The cross-linked network ligand has the same solubility as the first unit.

10. The quantum dot material as described in claim 9, wherein, The second photosensitive group includes a carbon-carbon double bond.

11. The quantum dot material of claim 10, wherein, The second photosensitive group has the following structure: R1 includes alkyl groups with 1-4 carbon atoms, and * indicates a linking site.

12. The quantum dot material as claimed in claim 9, wherein, The second dissolving group has the following structure: R2 includes alkylene groups with 1-3 carbon atoms, and * indicates a linking site.

13. The quantum dot material as described in claim 9, wherein, The second coordinating group includes at least one of amino, carboxylic acid, mercapto, phosphino, phosphoxy, or dithiol.

14. The quantum dot material according to any one of claims 9-13, wherein, The second ligand further includes a third linking group located between the second coordinating group and the second dissolving group, the third linking group comprising an alkylene group having 1-6 carbon atoms.

15. The quantum dot material as described in claim 14, wherein, The structure of the second ligand includes 16. A method for patterning quantum dot layers, wherein, include: The quantum dot material according to any one of claims 1-15 and the photoinitiator are dissolved in a first solvent to obtain a mixed solution, and the mixed solution is spin-coated onto one side of a substrate to form a quantum dot material film; The target area of ​​the quantum dot material film is exposed to light of a preset wavelength. Under the initiation of the photoinitiator, the first photosensitive group of the first ligand in the target area undergoes bond breaking, making the quantum dot material film in the target area insoluble in the first solvent. The exposed quantum dot material film is developed using the first solvent to form a patterned quantum dot layer in the target area.

17. The patterning method for quantum dot layers as described in claim 16, wherein, While the first photosensitive group of the first ligand in the target region undergoes bond breaking under the initiation of the photoinitiator, the second photosensitive group of the second ligand in the target region also undergoes a cross-linking reaction, making the quantum dot material film in the target region insoluble in the first solvent.

18. A quantum dot light-emitting device, wherein, It includes an anode, a quantum dot layer, and a cathode stacked together. The quantum dot layer includes a quantum dot body and a first unit connected to the surface of the quantum dot body. The first unit includes a first coordinating group and a first dissolving group.

19. A quantum dot light-emitting device, wherein, The light-emitting structure includes a light-emitting structure and a quantum dot layer located on the light-emitting side of the light-emitting structure. The quantum dot layer includes a quantum dot body and a first unit connected to the surface of the quantum dot body. The first unit includes a first coordinating group and a first dissolving group.

20. The quantum dot light-emitting device as described in claim 18 or 19, wherein, The structure of the quantum dot layer includes at least one of the following: in, Represents the quantum dot entity, where n is any integer from 1 to 5.

21. The quantum dot light-emitting device as described in claim 20, wherein, The quantum dot layer also includes cross-linked network ligands connected to the surface of the quantum dot body.

22. The quantum dot light-emitting device as described in claim 21, wherein, The structure of the quantum dot layer includes at least one of the following: in, Represents the quantum dot entity, where n is any integer from 1 to 5.

23. A display device, wherein, Including the quantum dot light-emitting device as described in any one of claims 18-22.

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