Quantum dot ink, method for patterning quantum dot layer, and quantum dot layer

Abstract

The application discloses a quantum dot ink, a quantum dot layer patterning method and a quantum dot layer. By adding a small amount of rigid viscosity regulator into the quantum dot ink, the viscosity of the overall solution system of the quantum dot ink is improved, and the uniformity of large-area film formation is improved. After large-area film formation is performed on the quantum dot ink provided by the application (wet film state), the wet film can be irradiated before drying treatment is performed on the wet film. The photosensitive groups of the viscosity regulator in the wet film system are broken, and then the small molecular branched chains are dissociated from the molecular main chains to become free small molecules. In the drying process, the free small molecules are vaporized and volatilized from the quantum dot film system. After drying, the viscosity regulator as a whole presents a large number of small molecular branched chains dissociated from the molecular main chains, and only a small amount of molecular main chains exist in the quantum dot film. Therefore, the viscosity regulator added in the application does not affect the electrical performance of the quantum dot film after drying.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a quantum dot ink, a quantum dot layer patterning method and a quantum dot layer. BACKGROUND

[0002] Quantum dots (QDs), also known as nanocrystals, are a kind of nanometer particles composed of II-VI or III-V elements. The particle size of quantum dots is generally between 1-20 nm. Due to the quantum confinement of electrons and holes, the continuous energy band structure becomes discrete energy level structure, and after excitation, it can emit fluorescence.

[0003] With the in-depth development of quantum dot preparation technology, the stability and light-emitting efficiency of quantum dots are continuously improved, the research of quantum light emitting diode (QLED) is continuously deepened, and the application prospect of QLED in the display field is increasingly bright. SUMMARY

[0004] The embodiments of the present application provide a quantum dot ink, a quantum dot layer patterning method and a quantum dot layer, which are used for adjusting the viscosity of the quantum dot ink. The specific scheme is as follows:

[0005] The quantum dot ink provided by the embodiments of the present application comprises quantum dot material and viscosity adjusting agent, and the viscosity adjusting agent has the following structural general formula:

[0006]

[0007] Among them, It is a rod-shaped n conformation molecular backbone, * is methyl, methoxy, ethyl or ethoxy, and n is an integer greater than or equal to 10;

[0008] Ra is a first polarity adjusting group configured to adjust the polarity and solubility of the viscosity adjusting agent;

[0009] Rb is a second polarity adjusting group configured to adjust the polarity and solubility of the viscosity adjusting agent;

[0010] Rl represents a connecting structure comprising a photosensitive group, and the photosensitive group is configured to undergo a bond breaking reaction after light irradiation;

[0011] Rs represents a dissociation group, and Rs is configured to adjust the whole molecule of the viscosity adjusting agent to be a rigid molecule before light irradiation, and Rs is configured to be gasified and volatilized after drying treatment after light irradiation.

[0012] Optionally, in the quantum dot ink provided by the embodiment of the present application, n = 10-30, n = 30-50, n = 50-80, n = 80-100, or n = 80-150, or n = 100-200.

[0013] Optionally, in the quantum dot ink provided by the embodiment of the present application, the alkene polymerizable main chain comprises is an alkene polymerizable main chain, a polyethylene glycol main chain, a polyether main chain, an aniline polymer, a carbazole polymer, or a fluorene-based polymer; wherein

[0014] The mass of the viscosity modifier comprising the alkene polymerizable main chain is not more than 20% of the mass of the quantum dot material;

[0015] The mass of the viscosity modifier comprising the polyethylene glycol main chain or the polyether main chain is not more than 35% of the mass of the quantum dot material;

[0016] The mass of the viscosity modifier comprising the aniline polymer, the carbazole polymer, or the fluorene-based polymer is not more than the total mass of the mass of the quantum dot material.

[0017] Optionally, in the quantum dot ink provided by the embodiment of the present application, the alkene polymerizable main chain comprises

[0018] The polyethylene glycol main chain comprises

[0019] The polyether main chain comprises

[0020] The aniline polymer comprises

[0021] The carbazole polymer comprises

[0022] The fluorene-based polymer comprises

[0023] Optionally, in the quantum dot ink provided by the embodiment of the present application, Ra is a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group, a benzyl group, a hydroxyl group, a sulfydryl group, an amine group, an ester group, an ether group, a halogen atom, or a benzene sulfonic acid group.

[0024] Optionally, in the quantum dot ink provided by the embodiment of the present application, Rb is a methylene group, an ethylene group, a propyl group, a butyl group, an amine group, a p-phenyl group, an o-phenyl group, an m-phenyl group, an oxygen atom, a sulfur atom, an ester group and derivatives, a carbonyl group, an ether group, an amide bond, a glycol group, or a phenoxy group.

[0025] Optionally, in the quantum dot ink provided by the embodiment of the present application, Rl is

[0026] Rcleft end is connected with Rb, and Ruvright end is connected with Rs;

[0027] or, Rl is Ruvleft end is connected with Rb, and Rc' right end is connected with Rs;

[0028] wherein, Ruv is the photosensitive group, and Rc and Rc' both represent alkane group, aromatic hydrocarbon group or nitrogen / oxygen / sulfur heteroatom-containing group.

[0029] Optionally, in the above quantum dot ink provided by the embodiment of the present application, the structure general formula of Ruv is * in the formula is a connection site.

[0030] Optionally, in the above quantum dot ink provided by the embodiment of the present application, the alkane group, aromatic hydrocarbon group or nitrogen / oxygen / sulfur heteroatom-containing group includes methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, nitrile group, amine group, carbonyl group, ester group, amide bond, hydroxyl group and mercapto group.

[0031] Optionally, in the above quantum dot ink provided by the embodiment of the present application, Rs is saturated aliphatic hydrocarbon, unsaturated aliphatic hydrocarbon or polyolefin and polyolefin derivative.

[0032] Optionally, in the above quantum dot ink provided by the embodiment of the present application, the structure general formula of the saturated aliphatic hydrocarbon is *-C x H 2x+1 * in the formula is a connection site, and x is an integer greater than or equal to 3.

[0033] Optionally, in the above quantum dot ink provided by the embodiment of the present application, the unsaturated aliphatic hydrocarbon contains alkene, alkyne, benzene ring, five-membered ring and six-membered ring alkane group, and the number of contained carbon atoms should be at least no less than 3.

[0034] Optionally, in the above quantum dot ink provided by the embodiment of the present application, the structure general formula of the polyolefin and polyolefin derivative is:

[0035]

[0036] * in the formula is a connection site, and m is any integer from 1 to 15.

[0037] Rx is -H, -OH, -SH, -COOH, -C y H 2y+1 , -O-C y H y+1 , -S-C y Hy+1 -CH2-O-C y H y+1 -CH2-O-C y H 2y -OH、-C y H 2y -SH、-C y H 2y -COOH、 y is any integer from 1 to 5;

[0038] or, Rx is -F, -Cl, -Br, -I,

[0039] R' is -CH3, -CH2-CH3, -OH, -SH, -COOH, -NH2, -NO2, -O-CH3, F, Cl, Br, I.

[0040] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present application, the structure of the viscosity regulator is

[0041]

[0042] Correspondingly, the embodiments of the present application further provide a method for patterning a quantum dot layer, comprising:

[0043] The above-mentioned quantum dot ink provided by the embodiments of the present application is used to form a quantum dot film;

[0044] The quantum dot film is exposed to light, and the photosensitive group in the viscosity regulator undergoes a bond-breaking reaction, and Rs is dissociated into free molecules;

[0045] The quantum dot film after light exposure is subjected to a drying treatment, and Rs is gasified and volatilized;

[0046] The quantum dot film after the drying treatment is subjected to a patterning process to obtain a patterned quantum dot layer. Correspondingly, the embodiments of the present application further provide a quantum dot layer, comprising a plurality of patterned sub-pixels, each of the sub-pixels comprising quantum dot material and

[0047] wherein, is a rod-shaped molecular main chain, * is a methyl group, a methoxy group, an ethyl group or an ethoxy group, and n is an integer greater than or equal to 10;

[0048] Ra is a first polarity adjusting group;

[0049] Rb is a second polarity adjusting group;

[0050] R11 represents a remaining group after the photosensitive group of R1 in the quantum dot ink provided by the embodiments of the present application is broken.

[0051] Optionally, in the quantum dot layer provided by the embodiments of the present application, has a structure of

[0052]

[0053]

[0054] Correspondingly, the embodiments of the present application also provide a quantum dot light-emitting device comprising the quantum dot layer provided by the embodiments of the present application.

[0055] Correspondingly, the embodiments of the present application also provide a display device comprising the quantum dot light-emitting device provided by the embodiments of the present application.

[0056] The beneficial effects of the embodiments of the present application are as follows:

[0057] The quantum dot ink, the method for patterning a quantum dot layer and the quantum dot layer provided by the embodiments of the present application can realize the viscosity adjustment of the quantum dot ink by adding the viscosity regulator in the quantum dot ink, the molecular main chain of the viscosity regulator is connected with a large number of small molecular branches (Rs), the molecular main chain can be stabilized in a rod-like conformation due to the steric hindrance between the large number of small molecular branches, and the viscosity regulator as a whole presents rigidity, the overall solution system viscosity of the quantum dot ink can be improved by adding a small amount of such rigid molecules in the quantum dot ink, and the uniformity of large-area film formation is improved, so that the viscosity regulator can realize the viscosity adjustment of the quantum dot ink; and after the large-area film formation (wet film state) by using the quantum dot ink provided by the embodiments of the present application, the wet film can be irradiated (for example, UV irradiation) before the drying treatment of the wet film, so that the photosensitive group of the viscosity regulator in the wet film system is broken, and then the small molecular branches (Rs) are dissociated from the molecular main chain to become free small molecules, and then in the drying process, the free small molecules are volatilized from the quantum dot film system. After drying, the large number of small molecular branches (Rs) of the viscosity regulator as a whole present rigidity are dissociated from the molecular main chain, so that only a small amount of molecular main chains exist in the quantum dot film, and therefore the added viscosity regulator does not affect the electrical properties of the quantum dot film after drying. Therefore, the quantum dot ink provided by the embodiments of the present application can improve the viscosity of the quantum dot ink, and can remove the main added components from the dry film during the drying process of the wet film. BRIEF DESCRIPTION OF DRAWINGS

[0058] Figure 1 The effect dissociation schematic diagram of the viscosity regulator provided by the embodiments of the present application after the large-area film formation and the UV irradiation;

[0059] Figure 2 As Chemical reaction principle diagram of the bond breaking reaction of the photosensitive group in R1 under UV light irradiation;

[0060] Figure 3 As Chemical reaction principle diagram of the photosensitive bond breaking reaction under UV light irradiation;

[0061] Figure 4 As Synthetic route diagram of the compound;

[0062] Figure 5 As Chemical reaction principle diagram of the photosensitive bond breaking reaction under UV light irradiation;

[0063] Figure 6 As Flowchart of a method for patterning a quantum dot layer provided by an embodiment of the present application;

[0064] Figure 7 As

[0065] Figure 8 As DETAILED DESCRIPTION

[0066] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described below in connection with the drawings of the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. And in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0067] Unless otherwise defined, the technical terms or scientific terms used in the present application shall be understood as the usual meanings understood by those of ordinary skill in the art to which the present application belongs. The "includes" or "contains" and similar words used in the present application mean that the elements or objects before the words cover the elements or objects listed after the words and their equivalents, and do not exclude other elements or objects. The "connection" or "connection" and similar words are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. "In", "out", "up", "down" and the like are only used to represent relative positional relationships, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0068] It is to be noted that the dimensions and shapes of the various figures in the drawings do not reflect true proportions, but are intended for the purpose of illustration only. Identical or similar elements or elements having identical or similar functions are denoted by the same reference signs throughout the entire description.

[0069] Large-area uniform film formation of quantum dots is one of the basic conditions for commercial production of QLEDs, and is also a prerequisite for direct photolithography process to achieve patterning. In existing large-area film formation processes, slit coating, blade coating, screen printing, etc. are common large-area film formation processes. These film formation processes have their own applicable ranges and requirements for the viscosity of quantum dot ink used for film formation. When the viscosity of the quantum dot ink is too low, the amount of liquid and the wet film shape cannot be well controlled, resulting in film formation failure, such as uneven film thickness, mura, etc. Among them, the quantum dot layer is an indispensable important functional layer in QLED devices / displayers. The traditional quantum dot ink usually cannot be well formed in a large area because the viscosity is too low to match the thin film coating equipment. In order to adjust the viscosity of the quantum dot ink, it is necessary to change the solvent system or add a certain amount of components that can increase the viscosity in the quantum dot ink. However, different solvent systems, whether single-component solvents or multi-component solvents, need to have sufficient solubility and stability for quantum dots, and solvents that meet this condition can be screened out of many types, which is a very difficult thing. On the other hand, after quantum dot film coating, most of them are in a wet film state, and usually need an effective drying process to ensure the final film formation quality of the quantum dot film. If some components are added to the quantum dot ink only to increase the viscosity of the ink or high-viscosity solvents are used, it is often necessary to have a matching drying condition to realize that the added components or high-viscosity solvents can be volatilized after the QD is dried to form a film (not left in the quantum dot dry film), but high-viscosity components are not easy to volatilize and remove, thereby damaging the electrical properties of the device after the quantum dot is formed.

[0070] In order to facilitate large-area coating and film formation of quantum dot ink without damaging the electrical properties of the device after the quantum dot is formed, an embodiment of the present application provides a quantum dot ink, which comprises quantum dot material and viscosity regulator, and the viscosity regulator has the following general structure:

[0071]

[0072] Among them, is a rod-shaped n-conformation molecular main chain, * is a polymer end-capping group, for example, * can be but is not limited to methyl, methoxy, ethyl or ethoxy, and n is an integer greater than or equal to 10;

[0073] Ra is the first polarity regulating group, which is configured to regulate the polarity and solubility of the viscosity modifier;

[0074] Rb is a second polarity regulating group, configured to adjust the polarity and solubility of viscosity modifiers;

[0075] Rl represents a linkage structure containing a photosensitive group, which is configured to undergo a bond-breaking reaction upon light irradiation;

[0076] Rs represents a dissociative group. Before light exposure, Rs is configured as a rigid molecule to adjust the viscosity modifier. After light exposure, Rs is configured to vaporize and volatilize after drying.

[0077] The quantum dot ink provided in this invention, by adding a viscosity modifier to the quantum dot ink, has a large number of small molecular branches (Rs) attached to its molecular backbone. Due to the steric hindrance between these small molecular branches, the molecular backbone can be stabilized in a rod-like conformation, making the viscosity modifier as a whole rigid. Adding a small amount of this rigid molecule to the quantum dot ink can increase the viscosity of the overall quantum dot ink solution system, improving the uniformity of large-area film formation. Therefore, the viscosity modifier can achieve the effect of regulating the viscosity of the quantum dot ink. Furthermore, after large-area film formation (wet film state) using the quantum dot ink provided in this invention, the wet film includes the viscosity modifier, such as... Figure 1 As shown in (A), Figure 1 Figure (A) is a simplified schematic diagram of a viscosity modifier, where rectangles represent the main molecular chain of the viscosity modifier, circles represent photosensitive groups in Rl, and dendritic lines represent small molecule branches (Rs). Before drying the wet film, it can be exposed to light (e.g., UV light) to break the bonds of the photosensitive groups of the viscosity modifier in the wet film system. Subsequently, the small molecule branches (Rs) dissociate from the main molecular chain, becoming free small molecules, such as... Figure 1 As shown in (B); subsequently, during the drying process (VCD / bake), the free small molecules vaporize and volatilize into the quantum dot film system, as shown in (B). Figure 1 As shown in (C), after drying, the viscosity modifier exhibits a rigid structure with numerous small molecular branches (Rs) dissociating from the molecular backbone. Therefore, only a small amount of the molecular backbone remains in the quantum dot film, and the added viscosity modifier does not affect the electrical properties of the quantum dot film after drying. Thus, this invention provides a quantum dot ink that can simultaneously improve the viscosity of the quantum dot ink and allow the main additive components to evaporate and be removed from the dry film during the wet film drying process.

[0078] It should be noted that, as verified by the inventors in this case, it possesses a general structural formula. The viscosity regulator can be dissolved in the quantum dot solution to form a stable mixed solution with the quantum dots, thereby laying a foundation for large-area film formation of quantum dot materials.

[0079] As shown in Figure 2 , Figure 2 For Under UV light, the chemical reaction principle diagram of the bond cleavage reaction of the photosensitive group in R1 is shown, R11 in the product represents the remaining group of R1 after the bond cleavage of the photosensitive group in the reactant, Rs' represents the overall structure of the photosensitive group connected to Rs after the bond cleavage, and then the small molecule branch (Rs) is separated from the molecular main chain to become a free small molecule.

[0080] Optionally, the large-area film formation process of the quantum dot ink can include slot coating, blade coating, screen printing, etc., and the drying process can include vacuum concentration drying (VCD), baking, natural drying, etc.

[0081] It should be noted that the quantum dot ink provided by the embodiments of the present application is not only suitable for manufacturing the light-emitting layer of the electroluminescent QLED device (i.e., the light-emitting layer between the cathode and the anode), but also suitable for manufacturing the photoluminescent layer (such as the structure of white light OLED + color film layer), that is, the patterned quantum dot layer manufactured by the quantum dot ink provided by the embodiments of the present application can be used as the color film layer in the white light OLED + color film layer. Of course, it is not limited to this, for example, it can also be used as the light-emitting layer in the light source.

[0082] In some embodiments, in the above-mentioned quantum dot ink provided by the embodiments of the present application, n represents the number of repeating units (or the degree of polymerization), when n is greater than or equal to 10, the viscosity regulator can better play a role in adjusting the viscosity of the quantum dot ink. Optionally, n = 10-30, n = 30-50, n = 50-80, n = 80-100, or n = 80-150, or n = 100-200, the corresponding n value can be selected according to the molecular weight of the molecular main chain.

[0083] In some embodiments, in the above-mentioned quantum dot ink provided by the embodiments of the present application, in order to match different quantum dot material systems, the molecular main chain in the embodiments of the present application may have n types, for example may be an n-olefin polymer main chain (also known as a polyolefin main chain), and the structure of the olefin polymer main chain can be The structure of the corresponding viscosity regulator can be Because the molecular backbone of this type of viscosity modifier is difficult to vaporize during the drying process, it cannot be completely removed from the quantum dot (QD) film. Therefore, when the quantum dot ink of this invention is used to fabricate the quantum dot light-emitting layer in QLED devices, the amount of this type of viscosity modifier added needs to be controlled to avoid affecting the transport of charge carriers in the QD film. Optionally, the quantum dot ink of this invention adds The mass of the olefin polymer backbone should not exceed 20% of the mass of the quantum dot material (including ligand molecules) in the quantum dot ink. Being nonpolar, these molecules are more suitable for quantum dot material systems in nonpolar solvent systems, such as alkane solvents like octane / heptane, and benzene derivatives like chlorobenzene / toluene / xylbenzene, but they are not limited to nonpolar solvent systems. This is because... The overall polarity / nonpolarity can be adjusted by the polarity type of the Ra or Rb groups, thereby regulating the polarity / nonpolarity of the molecular backbone.

[0084] In some embodiments, in the quantum dot ink provided in the present invention, It can be a polyethylene glycol-based backbone (or "polyethylene oxide-based backbone" / "polyethylene oxide-based backbone") or a polyether-based backbone, and the structure of the polyethylene glycol backbone can be... The structure of the corresponding viscosity modifier can be The structure of the polyether backbone can be... The structure of the corresponding viscosity modifier can be The molecular backbone of the two types of viscosity modifiers mentioned above These materials possess a certain charge transport capability and can play a role in carrier transport in QD films. However, considering their limited charge transport capability—that is, the charge transport capability of these two structural types is relatively weak—they exhibit some semiconductor properties but also some insulating properties. Therefore, it is necessary to control their addition amount in quantum dot inks to avoid affecting carrier transport in QD films. Optionally, the quantum dot ink of the present invention adds... The mass of the polymer should not exceed 35% of the mass of the quantum dot material (including ligand molecules) in the quantum dot ink. This polyethylene glycol backbone... and polyether backbone All of these are polar molecules, making them more suitable for quantum dot material systems in solvent systems with a certain degree of polarity. Examples include polar alcohols such as ethanol / isopropanol, polar or amphoteric esters such as propylene glycol monomethyl ether acetate / ethyl acetate, and polar solvents such as water. However, they are not limited to polar solvent systems, because... The overall polarity / non-polarity of the molecular main chain can be adjusted by the polarity type of the Ra or Rb group.

[0085] In some embodiments, in the above-mentioned quantum dot ink provided by the embodiments of the present application, The aniline-based polymer, the carbazole-based polymer or the fluorene-based polymer can be The structure of the carbazole-based polymer can be The structure of the fluorene-based polymer can be The structures of the viscosity adjustors corresponding to the above-mentioned three molecular main chains can be Since the three molecular main chains all have good charge transport capacity (especially the transport of holes), the addition of the three molecular main chains in the quantum dot ink can enhance the carrier transport capacity of the QD film to a certain extent, thereby improving the injection of holes; meanwhile, the electron blocking capacity of the QD film is improved, which is overall conducive to the balance of the injection of carriers. In consideration of the film forming performance of the quantum dot ink, the mass of the three viscosity adjustors added in the quantum dot ink of the present application can not exceed the total mass of the quantum dot material (including the ligand molecules) in the quantum dot ink.

[0086] Optionally, the viscosity adjustor provided by the embodiments of the present application is selected from

[0087] The addition of the viscosity adjustor can increase the hole transport capacity of the QD film.

[0088] In some embodiments, in the above-mentioned quantum dot ink provided by the embodiments of the present application, The Ra (first polarity adjusting group) in the above-mentioned formula (1) can be a non-dissociated side chain group on the molecular main chain, which plays a role in adjusting the physical properties such as polarity of the viscosity adjustor, and the Ra can be but is not limited to a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group, a benzyl group, a hydroxyl group, a sulfydryl group, an amine group, an ester group, an ether group, a halogen atom or a benzene sulfonic acid group.

[0089] In some embodiments, in the above-mentioned quantum dot ink provided by the embodiments of the present application, The Rb (second polarity adjusting group) in the above-mentioned formula (1) plays a role in adjusting the physical properties such as polarity of the viscosity adjustor and connecting the Rl with the molecular main chain, and the Rb can be but is not limited to a methylene group, an ethylene group, a propyl group, a butyl group, an amine group, a p-phenyl group, an o-phenyl group, an m-phenyl group, an oxygen atom, a sulfur atom, an ester group and derivatives, a carbonyl group, an ether group, an amide bond, a glycol group or a phenoxy group.

[0090] In some embodiments, when the force of Ra is not enough to adjust the polarity, or when the viscosity modifier needs to be adjusted to be amphoteric, Rb can be a polarity supplement or a reverse polarity adjustment; specifically, when Ra and Rb are of the same polarity, the polarity of the viscosity modifier is complementary; when the polarity of Ra and Rb is opposite, the viscosity modifier can be given the characteristics of being amphoteric.

[0091] In some embodiments, in the above-mentioned quantum dot ink provided by the embodiments of the present application, Rl (connection structure) in the above-mentioned formula mainly plays a role of connecting the main chain of the molecule with the dissociation group (i.e. the small molecule branch Rs), and considering the feasibility of actually synthesizing the viscosity modifier of the present application, Rl can be a structure containing an amide group, an ester group, an alkane group containing a nitrogen-containing five-membered heterocycle, or a carbon-sulfur bond group, etc., and the amide group, the ester group, the alkane group containing a nitrogen-containing five-membered heterocycle, or the carbon-sulfur bond group mainly plays a role of connection.

[0092] Optionally, Rl can be Rc left end is connected with Rb, and Ruv right end is connected with Rs;

[0093] Or, Rl can be

[0094] Ruv left end is connected with Rb, and Rc' right end is connected with Rs.

[0095] Specifically, Ruv is a photosensitive group (which can undergo a bond breaking reaction under UV light), and the general structure of Ruv can be The * in the formula is a connection site; for example, when Rl is , The left end * in the formula is connected with Rc', and the right end * is connected with Rs; when Rl is , The left end * in the formula is connected with Rb, and the right end * is connected with Rc.

[0096] In some embodiments, the general structure of Ruv can be: Rl is

[0097] For example, in order to facilitate description, The sites (left and right ends *) in the formula where it is connected with Rc' and Rs are marked in the formula, and this is taken as an example for description. Of course, in some embodiments, the sites where Rc' and Rs are connected can also be interchanged, for example, the left end * can also be connected with Rs, and the right end * is connected with Rc'.

[0098] Optionally, Rc and Rc' in each structure of Rl can represent an alkyl group, an aromatic hydrocarbon group, or a group containing nitrogen / oxygen / sulfur heteroatoms.

[0099] Optionally, Rc and Rc' in each structure of Rl can be the same or different.

[0100] In some embodiments, in the above-mentioned quantum dot ink provided by the embodiments of the present application, the above-mentioned alkyl group, aromatic hydrocarbon group, or group containing nitrogen / oxygen / sulfur heteroatoms can include but is not limited to a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a phenyl group, a nitrile group, an amine group, a carbonyl group, an ester group, an amide bond, a hydroxyl group, and a mercapto group.

[0101] Optionally, Rc and Rc' can be but are not limited to

[0102] In some embodiments, in the above-mentioned quantum dot ink provided by the embodiments of the present application, Rs (a dissociable group) in the above-mentioned formula (I) represents a dissociable side chain group, which can be separated from the main chain of the molecule by breaking the bond of Ruv in Rl under UV light, so as to realize the free state of Rs and be volatilized by gas flow in the drying process (such as VCD).

[0103] Optionally, Rs can be a saturated aliphatic hydrocarbon, and the structural general formula of the saturated aliphatic hydrocarbon can be *C x H 2x +1 In the formula, * is a connection site (indicating connection with Rl), and x is an integer greater than or equal to 3. Specifically, Rs can include any conformation satisfying the above-mentioned structural general formula; preferably, Rs is in a non-linear conformation, because the non-linear conformation has more obvious steric hindrance effect, which can make the molecule of the viscosity regulator more rigid, and is conducive to the adjustment of the viscosity regulator to the viscosity of the quantum dot ink system.

[0104] Optionally, Rs can also be an unsaturated aliphatic hydrocarbon, which can contain an alkene, an alkyne, a benzene ring, a five-membered ring, or a six-membered ring alkane group, wherein the number of carbon atoms contained therein should be at least not less than 3.

[0105] Optionally, Rs can also be a polyolefin and a polyolefin derivative, and the structural general formula of the polyolefin and the polyolefin derivative can be:

[0106]

[0107] In the formula, * is a connection site (indicating connection with Rl), and m can be any integer from 1 to 15.

[0108] Rx can be -H, -OH, -SH, -COOH, or -C. y H 2y+1 -OC y H y+1 -SC y H y+1 -CH2-OC y H y+1 -C y H 2y -OH, -C y H 2y -SH、-C y H 2y -COOH, y is any integer from 1 to 5;

[0109] Alternatively, Rx can be -F, -Cl, -Br, -I,

[0110] R' can be -CH3, -CH2-CH3, -OH, -SH, -COOH, -NH2, -NO2, -O-CH3, F, Cl, Br, or I.

[0111] In some embodiments, the structure of the viscosity modifier in the quantum dot ink provided in the present invention can be...

[0112] It should be noted that the structures of the above viscosity modifiers are only examples, and are not limited to these structures.

[0113] It should be noted that m = 1 to 15 in the above structures is to limit the molecular weight of Rs. If the molecular weight is too large (m > 16), it will not easily vaporize / evaporate with the solvent during the drying process. If the molecular weight is relatively small (m = 1 to 15), Rs that have detached from the molecular backbone will easily vaporize and evaporate during the VCD process or heat annealing process.

[0114] like Figure 3 As shown, Figure 3 Taking n=100 as an example, the corresponding viscosity modifier structure is as follows: The principle behind this structure is that it undergoes a photosensitive bond-breaking reaction under UV light.

[0115] Optionally, Rx is Taking m=10 as an example, the structure of the viscosity modifier is as follows: The synthetic route for this structure is as follows: Figure 4 As shown.

[0116] like Figure 5As shown in Figure 5 As The principle of photosensitive scission reaction under UV light, the product As Figure 2 Rs'(vaporized and volatilized during drying) in the product Remain in the QD film and do not affect the electrical properties of the QD film.

[0117] Optionally, the quantum dot material in the embodiment of the present application can include but is not limited to: CdS, CdSe, ZnSe, ZnTeSe, InP, PbS, CsPbCl3, CsPbBr3, CsPbI3, CdS / ZnS, CdSe / ZnS, ZnSe, ZnSeTe, InP / ZnS, PbS / ZnS, CsPbCl3 / ZnS, CsPbBr3 / ZnS, CsPbI3 / ZnS, CdS / ZnSeS / ZnS, CdSe / ZnSeS / ZnS, ZnSe / ZnSeS / ZnS, ZnSeTe / ZnSeS / ZnS, InP / ZnS, PbS / ZnS, CsPbCl3 / ZnS, CsPbBr3 / ZnS, CsPbI3 / ZnS, etc. The shape of the quantum dot material includes but is not limited to spherical, spherical, ellipsoidal, polyhedral, rod-shaped, cross-shaped, ring-shaped, etc. Any geometrically shaped quantum dot material.

[0118] In summary, the quantum dot ink provided by the embodiment of the present application can realize large-area uniform coating and film formation without damaging the electrical properties of the device after quantum dot film formation.

[0119] Based on the same inventive concept, the embodiment of the present application also provides a method for patterning a quantum dot layer, as shown in Figure 6 As shown, the method comprises:

[0120] S601, forming a quantum dot film by using the above-mentioned quantum dot ink provided by the embodiment of the present application;

[0121] S602, exposing the quantum dot film to light, and the photosensitive group in the viscosity regulator undergoes a scission reaction, and Rs is dissociated into a free molecule;

[0122] S603, drying the quantum dot film after light exposure, and Rs is vaporized and volatilized;

[0123] S604, patterning the quantum dot film after drying treatment to obtain a patterned quantum dot layer.

[0124] The method for patterning the quantum dot layer provided by the embodiment of the present application can form a quantum dot film by using quantum dot ink added with the viscosity modifier, and the viscosity of the overall solution system of the quantum dot ink can be improved by the viscosity modifier, so that the present application can realize large-area uniform film formation of quantum dots; and before drying treatment is performed on the quantum dot film (wet film), the wet film is irradiated (for example, UV irradiation), so that the light-sensitive group of the viscosity modifier in the wet film system is broken, and then the small molecular branched chain (Rs) is dissociated from the molecular main chain to become a free small molecule; and then in the drying treatment process, the free small molecule is volatilized from the quantum dot film system. After drying treatment, the viscosity modifier as a whole presents a large number of small molecular branched chains (Rs) dissociated from the molecular main chain, so that only a small amount of molecular main chain exists in the quantum dot film, and therefore the viscosity modifier added does not affect the electrical properties of the quantum dot film after drying. Therefore, the present application provides a patterned quantum dot layer which can be made into a large area and has better electrical properties.

[0125] In a specific implementation, the quantum dot layer made by the embodiment of the present application can not only be used as a light-emitting layer in a QLED device, but also be used as a light conversion film layer in a backlight source of a liquid crystal display screen, a color film layer in a liquid crystal display screen, a color film layer in a white light OLED device + color film layer, and the like.

[0126] Based on the same inventive concept, the embodiment of the present application further provides a quantum dot layer, which comprises a plurality of patterned sub-pixels, each sub-pixel comprising quantum dot material and

[0127] wherein, is a rod-shaped molecular main chain, is a methyl group, a methoxy group, an ethyl group or an ethoxy group, and n is an integer greater than or equal to 10;

[0128] Ra is a first polarity adjusting group;

[0129] Rb is a second polarity adjusting group;

[0130] Rl1 represents a remaining group after the light-sensitive group of Rl in the quantum dot ink provided by the embodiment of the present application is broken.

[0131] It should be noted that the above Ra, Rnb and Rl1 can be referred to the description of the aforementioned quantum dot ink, and will not be described here.

[0132] Optionally, The structure of can be but is not limited to

[0133]

[0134]

[0135] Based on the same inventive concept, the embodiment of the present application also provides a quantum dot light-emitting device comprising the quantum dot layer provided by the embodiment of the present application.

[0136] Optionally, the quantum dot light-emitting device provided by the present application can be a quantum dot light-emitting diode, a photodetector, a photovoltaic solar cell, etc., but is not limited thereto.

[0137] Optionally, the quantum dot light-emitting device provided by the present application can have the structure of a conventional optoelectronic device in addition to the quantum dot layer of the present application.

[0138] Optionally, the quantum dot light-emitting device provided by the present application can be a quantum dot light-emitting diode, as shown in Figure 7 and Figure 8 In addition to having the quantum dot layer 5 of the present application, the quantum dot light-emitting diode can also comprise a substrate 1, an anode 2, a hole injection layer 3, a hole transport layer 4, an electron transport layer 6, an electron injection layer 7, a cathode 8, etc., but is not limited thereto.

[0139] Specifically, the specific structure, material composition and preparation method of the substrate 1, the anode 2, the hole injection layer 3, the hole transport layer 4, the electron transport layer 6, the electron injection layer 7, the cathode 8, etc. of the quantum dot light-emitting diode according to the embodiment of the present application can adopt any suitable structure, material composition and preparation method without particular limitation.

[0140] Optionally, the structure of the quantum dot light-emitting diode provided by the embodiment of the present application can be an inverted structure as shown in Figure 7 or a normal structure as shown in Figure 8

[0141] Optionally, the light-emitting type of the quantum dot light-emitting diode can be a top light-emitting structure, a bottom light-emitting structure, or a double-sided light-emitting structure.

[0142] Based on the same inventive concept, the embodiment of the present application also provides a display device comprising the quantum dot light-emitting device provided by the embodiment of the present application. The principle of solving the problem of the display device is similar to that of the aforementioned quantum dot light-emitting device, and therefore the implementation of the display device can be referred to the implementation of the aforementioned quantum dot light-emitting device, and the repeated parts will not be described herein. The display device can be a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator, etc. or any product or component having a display function. Other essential components of the display device should be understood by those skilled in the art, and will not be described herein, nor should it be regarded as a limitation on the present application.

[0143] ​The quantum dot ink, the quantum dot layer patterning method and the quantum dot layer provided by the embodiment of the present application can realize viscosity adjustment of the quantum dot ink by adding a viscosity regulator in the quantum dot ink, the molecular main chain of the viscosity regulator is connected with a large number of small molecular branches (Rs), the molecular main chain can be stabilized in a rod-like conformation due to the steric hindrance between the large number of small molecular branches, the viscosity regulator as a whole presents rigidity, the viscosity of the overall solution system of the quantum dot ink can be improved by adding a small amount of the rigid molecule in the quantum dot ink, the uniformity of large-area film formation is improved, and therefore the viscosity regulator can realize the viscosity adjustment of the quantum dot ink; and after large-area film formation (wet film state) is performed by using the above quantum dot ink provided by the present application, the wet film can be irradiated (for example, UV irradiation) before drying treatment of the wet film, the photosensitive group of the viscosity regulator in the wet film system is broken, and then the small molecular branches (Rs) are dissociated from the molecular main chain to become free small molecules, and then in the drying treatment process, the free small molecules are volatilized from the quantum dot film system. Due to the dissociation of the large number of small molecular branches (Rs) from the molecular main chain after drying, only a small amount of molecular main chain exists in the quantum dot film, and therefore the added viscosity regulator does not affect the electrical properties of the quantum dot film after drying. Therefore, the present application provides a quantum dot ink which can improve the viscosity of the quantum dot ink and remove the main added components from the dry film in the drying process of the wet film.

[0144] Obviously, various modifications and changes can be made to the present application by those skilled in the art without departing from the spirit and scope of the present application. Accordingly, it is intended to include all such modifications and changes in the scope of the present application as claimed in the claims and their equivalents.

Claims

1. A quantum dot ink, characterized in that, It includes quantum dot materials and viscosity modifiers, wherein the viscosity modifiers have the following general structural formula: ； in, The molecular backbone has a rod-like conformation. It is methyl, methoxy, ethyl, or ethoxy, and n is an integer greater than or equal to 10; Ra is the first polarity regulating group, configured to regulate the polarity and solubility of the viscosity modifier; Rb is a second polarity regulating group, configured to regulate the polarity and solubility of the viscosity modifier; Rl represents a linkage structure containing a photosensitive group, which is configured to undergo a bond-breaking reaction upon light irradiation; Rs represents a dissociative group. Before light exposure, Rs is configured to adjust the overall molecule of the viscosity modifier to be a rigid molecule. After light exposure, Rs is configured to vaporize and volatilize after drying. Where Rl is , , or Rc is connected to Rb on the left, and Ruv is connected to Rs on the right. Or, Rl is , , or , Ruv connects to Rb on the left, and Rc' connects to Rs on the right; Wherein, Ruv is the photosensitive group, and Rc and Rc' both represent alkane groups, aromatic groups, or groups containing nitrogen / oxygen / sulfur heteroatoms.

2. The quantum dot ink as described in claim 1, characterized in that, n=10~30, n=30~50, n=50~80, n=80~100, or n=80~150, or n=100~200.

3. The quantum dot ink as described in claim 1, characterized in that, It can be an olefin polymer backbone, a polyethylene glycol backbone, a polyether backbone, an aniline polymer, a carbazole polymer, or a fluorene polymer; among which, The mass of the viscosity modifier comprising the olefin polymeric backbone does not exceed 20% of the mass of the quantum dot material; The mass of the viscosity modifier comprising the polyethylene glycol backbone or the polyether backbone does not exceed 35% of the mass of the quantum dot material; The mass of the viscosity modifier, including the aniline polymer, the carbazole polymer, or the fluorene polymer, does not exceed the total mass of the quantum dot material.

4. The quantum dot ink as described in claim 3, characterized in that, The olefin polymeric backbone includes ; The polyethylene glycol backbone includes ; The polyether backbone includes ; The aniline polymers include ; The carbazole polymers include ; The fluorene-based polymer includes .

5. The quantum dot ink as described in claim 1, characterized in that, Ra can be a hydrogen atom, methyl, ethyl, propyl, butyl, phenyl, benzyl, hydroxyl, mercapto, amino, ester, ether, halogen atom, or benzenesulfonic acid group.

6. The quantum dot ink as described in claim 1, characterized in that, Rb can be methylene, ethylene, propyl, butyl, amino, p-phenyl, o-phenyl, meta-phenyl, oxygen atom, sulfur atom, ester group and its derivatives, carbonyl, ether group, amide bond, glycol group or phenoxy.

7. The quantum dot ink as described in claim 1, characterized in that, The general structural formula of Ruv is: In this formula This is the connection site.

8. The quantum dot ink as described in claim 1, characterized in that, The alkane group, aromatic group, or group containing nitrogen / oxygen / sulfur heteroatoms includes methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, nitrile, amino, carbonyl, ester, amide bond, hydroxyl, and mercapto.

9. The quantum dot ink as described in claim 1, characterized in that, Rs can be saturated aliphatic hydrocarbons, unsaturated aliphatic hydrocarbons, polyolefins, or polyolefin derivatives.

10. The quantum dot ink as described in claim 9, characterized in that, The general structural formula of the saturated aliphatic hydrocarbons is: In this formula , where x is a connection point, and x is an integer greater than or equal to 3.

11. The quantum dot ink as described in claim 9, characterized in that, The unsaturated aliphatic hydrocarbons contain alkane groups such as alkenes, alkynes, benzene rings, five-membered rings, and six-membered rings, wherein the number of carbon atoms contained therein should be at least 3.

12. The quantum dot ink as described in claim 9, characterized in that, The general structural formula of the polyolefins and polyolefin derivatives is: ； Wherein in the formula For the connection point, m is any integer from 1 to 15; Rx represents -H, -OH, -SH, -COOH, and -C. y H 2y+1 -OC y H y+1 -SC y H y+1 -CH2-OC y H y+1 -C y H 2y -OH, -C y H 2y -SH、-C y H 2y -COOH, , , , y is any integer from 1 to 5; Alternatively, Rx can be -F, -Cl, -Br, or -I. , , , , , , , , R' is -CH3, -CH2-CH3, -OH, -SH, -COOH, -NH2, -NO2, -O-CH3, F, Cl, Br, I.

13. The quantum dot ink according to any one of claims 1-12, characterized in that, The viscosity modifier has the following structure: , or 。 14. A method for patterning quantum dot layers, characterized in that, include: Quantum dot films are formed using the quantum dot ink according to any one of claims 1-13; When the quantum dot film is exposed to light, the photosensitive groups in the viscosity modifier undergo a bond-breaking reaction, and Rs dissociates into free molecules. The quantum dot film after being exposed to light is dried, and Rs is vaporized and volatilized. The dried quantum dot film is patterned to obtain a patterned quantum dot layer.

15. A quantum dot layer, characterized in that, It includes a patterned plurality of sub-pixels, each of which comprises quantum dot material and ; in, The molecular backbone has a rod-like conformation. It is methyl, methoxy, ethyl, or ethoxy, and n is an integer greater than or equal to 10; Ra is the first polar regulating group; Rb is a second polarity regulating group; Rl1 represents the remaining group after the photosensitive group of Rl breaks its bond in the quantum dot ink as described in any one of claims 1-13.

16. The quantum dot layer as described in claim 15, characterized in that, The structure is , or .

17. A quantum dot light-emitting device, characterized in that, Includes the quantum dot layer as described in claim 15 or 16.

18. A display device, characterized in that, Including the quantum dot light-emitting device as described in claim 17.

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