Initiator, quantum dot light-emitting layer and method for manufacturing the same, light-emitting device, display device

Abstract

The present invention provides an initiator, a quantum dot, a quantum dot light-emitting layer, a light-emitting device, a display device, and a method for manufacturing a quantum dot light-emitting layer. The structural formula of the initiator is The image is JPEG2026514318000131.jpg51170, where R11~R15 are any of H, a group containing N and H, an ester group, and an alkyl group; R21~R24 are any of H, F, S, O, an ester group, an alkyl group, and a group containing N and H; R3 is any of S, O, an ester group, an amide group, an alkyl group, H, and F; R4 is any of an ester group, an alkyl group, and a group containing N and H; R31~R39 may or may not be present, and if at least one of R31~R39 is present, it is one of the ester group, alkyl group, and group containing N and H; n is a positive integer of 1 or more; the initiator group includes at least one of S, O, and a group containing N and H; and the initiator group refers to any group other than the benzophenone skeleton.

Description

[Technical Field]

[0001] This application claims priority to PCT International Application No. PCT / CN2023 / 083509, filed on 23 March 2023, the entirety of which is incorporated herein by reference.

[0002] This disclosure relates to the technology of displays, and more particularly to initiators, quantum dots, quantum dot light-emitting layers, light-emitting devices, display devices, and methods for manufacturing patterned quantum dot light-emitting layers. [Background technology]

[0003] Light-emitting diodes (LEDs) emit light by recombining electrons and holes to release energy. Light-emitting diodes include, but are not limited to, organic light-emitting diodes (OLEDs) and quantum dot light-emitting diodes (QLEDs). Quantum dots are a type of semiconductor nanomaterial that can bind excitons in three-dimensional space. They have excellent properties such as high quantum efficiency, a narrow excitation spectrum, high photostability, a long fluorescence lifetime, and good solution processing compatibility, making them highly applicable to high-quality displays. Quantum dot light-emitting diodes are devices that use quantum dots as the light-emitting material, and have superior advantages over organic light-emitting diodes, such as lower power consumption, higher color purity, and a wider color gamut. Therefore, quantum dot light emission technology is the most promising next-generation self-luminous display technology. [Overview of the project]

[0004] According to one aspect of this disclosure, an initiator is provided, the structural formula of which is [ka] R11, R12, R13, R14, and R15 are either the same or different from each other, and each of R11, R12, R13, R14, and R15 is selected from a hydrogen atom, a group containing a nitrogen atom and a hydrogen atom, an ester group, and an alkyl group; R21, R22, R23, and R24 are either the same or different from each other, and each of R21, R22, R23, and R24 is selected from a hydrogen atom, a fluorine atom, a sulfur atom, an oxygen atom, an ester group, an alkyl group, and a group containing a nitrogen atom and a hydrogen atom; R3 is selected from a sulfur atom, an oxygen atom, an ester group, an amide group, an alkyl group, a hydrogen atom, and a fluorine atom; and R4 is E The initiator group is one selected from a ster group, an alkyl group, and a group comprising a nitrogen atom and a hydrogen atom, and R31, R32, R33, R34, R35, R36, R37, R38, and R39 may or may not be present and may or may not be the same as one another, and if at least one of R31, R32, R33, R34, R35, R36, R37, R38, and R39 is present, it is one selected from an ester group, an alkyl group, and a group comprising a nitrogen atom and a hydrogen atom, n is a positive integer of 1 or more, and the initiator group comprises at least one of the sulfur atom, the oxygen atom, and the group comprising a nitrogen atom and a hydrogen atom, and the initiator group refers to any group other than the benzophenone skeleton.

[0005] In some embodiments, R31, R32, R33, R34, R35, R36, R37, R38, and R39 are all absent; R11, R12, R13, R14, and R15 are each selected from a hydrogen atom or a group containing a nitrogen atom and a hydrogen atom; R21, R22, R23, and R24 are each selected from a hydrogen atom or a fluorine atom; and R3 is one of the following selected from a sulfur atom, an oxygen atom, an ester group, an amide group, and an alkyl group.

[0006] In some embodiments, the group containing the nitrogen atom and hydrogen atom is a pyrrole group or a tertiary amine group.

[0007] In some embodiments, the structural formula of the initiator is [Chemical formula] is as follows.

[0008] In some embodiments, n = 3, and the structural formula of the initiator is [Chemical formula] or, n = 2, and the structural formula of the initiator is [Chemical formula] or, n = 4, and the structural formula of the initiator is [Chemical formula] or, n = 1, and the structural formula of the initiator is [Chemical formula] is as follows.

[0009] In some embodiments, the structural formula of the initiator is [Chemical formula] where x and y are both positive integers of 1 or more.

[0010] In some embodiments, the number of carbon atoms in the branched chain bonded to the nitrogen atom is 2 to 30.

[0011] According to another aspect of the present disclosure, an initiator is provided, which is a mixture of benzophenone and an amine compound or a mixture of a benzophenone derivative and an amine compound, and the structural formula of the benzophenone derivative is [Chemical formula] where R0 is any one selected from O, S, C6H5, OH, Br, Cl, I, and m is a positive integer of 0 or more.

[0012] In some examples, the amine compound is pyrrole or a tertiary amine.

[0013] According to another aspect of this disclosure, a quantum dot is provided, the quantum dot having a ligand on its surface, the structural formula of the ligand is [ka] R5 is coordinately bonded to the surface of the quantum dot and is selected from a mercapto group, a carboxyl group, or an amino group, R6 is selected from an ester group or an ether group, and R7 is selected from an ester group or an ether group, and the ligand is configured to photosensitize with an initiator described in any of the above examples under light irradiation.

[0014] In some embodiments, the structural formula of the ligand is [ka] That is the case.

[0015] According to yet another aspect of the present disclosure, a quantum dot light-emitting layer is provided which includes a plurality of quantum dots, at least some of which have ligands on their surfaces, and the quantum dot light-emitting layer is produced by crosslinking the ligand-containing quantum dots with an initiator as described in any of the above examples.

[0016] In some embodiments, the structural formula of the ligand is [ka] The structural formula of the initiator is [ka] The structural formula of the quantum dot light-emitting layer is [ka] Here, QD represents the quantum dot, and k is a positive integer greater than or equal to 1.

[0017] In some embodiments, the structural formula of the ligand is [ka] The structural formula of the initiator is [ka] The structural formula of the quantum dot light-emitting layer is [ka] Here, QD represents the quantum dot, and k is a positive integer greater than or equal to 1.

[0018] In some embodiments, the structural formula of the ligand is [ka] The structural formula of the initiator is [ka] The structural formula of the quantum dot light-emitting layer is [ka] Here, QD represents a quantum dot, and k is a positive integer greater than or equal to 1.

[0019] In some embodiments, the structural formula of the ligand is [ka] The initiator is a mixture of benzophenone and an amine compound, and the structural formula of the quantum dot light-emitting layer is [ka] The structural formula of the ligand is [ka] The initiator is a mixture of a benzophenone derivative and an amine compound, and the structural formula of the benzophenone derivative is [ka] The structural formula of the quantum dot light-emitting layer is [ka] R5 is selected from a mercapto group, a carboxyl group, or an amino group; R6 is selected from an ester group or an ether group; R7 is selected from an ester group or an ether group; R0 is selected from O, S, C6H5, OH, Br, Cl, or I; QD represents a quantum dot, k is a positive integer greater than or equal to 1, and m is a positive integer greater than or equal to 0.

[0020] In some embodiments, the quantum dot light-emitting layer includes a plurality of first quantum dot patterns, a plurality of second quantum dot patterns, and a plurality of third quantum dot patterns, wherein the first quantum dot patterns are configured to emit red light, the second quantum dot patterns are configured to emit green light, and the third quantum dot patterns are configured to emit blue light.

[0021] According to yet another aspect of the present disclosure, a light-emitting device is provided, comprising: a first electrode layer; a hole injection layer located on the first electrode layer; a hole transport layer located on the side of the hole injection layer away from the first electrode layer; a quantum dot light-emitting layer as described in any of the above embodiments located on the side of the hole transport layer away from the first electrode layer; an electron transport layer located on the side of the quantum dot light-emitting layer away from the first electrode layer; and a second electrode layer located on the side of the electron transport layer away from the first electrode layer.

[0022] According to yet another aspect of the present disclosure, a display device is provided which includes a plurality of light-emitting devices as described in any of the above embodiments, wherein at least two of the plurality of light-emitting devices are configured to emit light of different colors.

[0023] A further aspect of the present disclosure provides a method for manufacturing a patterned quantum dot light-emitting layer, comprising the steps of: providing a substrate; coating the substrate with a mixed solution, the mixed solution comprising quantum dots and an initiator, the surface of the quantum dots having ligands containing carbon-carbon double bonds, and the initiator being one of the initiators described in any of the above examples; and, under light irradiation, the initiator initiating a polymerization reaction of the carbon-carbon double bonds of the ligands to form a patterned quantum dot light-emitting layer.

[0024] In some embodiments, the method further includes the step of curing a mixed solution coated on the substrate to form an intermediate film layer. The step of forming a patterned quantum dot light-emitting layer by having the initiator initiate a polymerization reaction of the carbon-carbon double bonds of the ligands under light irradiation includes the steps of exposing the intermediate film layer using a mask plate, exposing the intermediate film layer by passing ultraviolet light through the mask plate, having the initiator initiate a polymerization reaction of the carbon-carbon double bonds of the ligands under ultraviolet light irradiation, and developing the intermediate film layer after the polymerization reaction using a developer, dissolving the unexposed portions of the intermediate film layer with the developer to form the patterned quantum dot light-emitting layer.

[0025] In some embodiments, the concentration of the quantum dots in the mixed solution is approximately 25-30 mg / mL, and the concentration of the initiator in the mixed solution is approximately 0.1-1.0 mg / mL. [Brief explanation of the drawing]

[0026] Hereinafter, each exemplary embodiment of the present disclosure will be described in detail with reference to the drawings, and in the drawings, [Figure 1] Figure 1 shows a schematic diagram of the mechanism of benzophenone photoinitiated radical polymerization. [Figure 2] Figure 2 shows a schematic diagram illustrating the initiation of carbon-carbon double bond polymerization by radicals. [Figure 3] Figure 3 shows the structural formula of the initiator according to the embodiments of this disclosure. [Figure 4] Figure 4 shows the mechanism of the triplet benzophenone structural unit in which tertiary amines inhibit oxygen inhibition. [Figure 5] Figure 5 shows the photosensitization mechanism of a benzophenone structural unit containing a sulfur atom. [Figure 6] Figure 6 shows a schematic diagram of the molecular structure of an initiator having multiple initiation sites according to an embodiment of the present disclosure. [Figure 7] Figure 7 shows the structural formula of the initiator according to the embodiments of this disclosure. [Figure 8] Figure 8 shows the synthesis steps for the intermediate product of the initiator SBP according to the embodiments of this disclosure. [Figure 9] Figure 9 shows the synthesis steps of the initiator SBP according to the embodiments of this disclosure. [Figure 10] Figure 10 shows the hydrogen nuclear magnetic resonance spectrum of the initiator SBP according to the embodiment of this disclosure. [Figure 11] Figure 11 shows the mass spectrum of the initiator SBP according to the embodiments of this disclosure. [Figure 12] Figure 12 shows the hydrogen nuclear magnetic resonance spectrum of SBP-COOH according to an embodiment of this disclosure. [Figure 13] Figure 13 shows the mass spectrum of SBP-COOH according to the embodiment of this disclosure. [Figure 14] Figure 14 shows the structural formula of initiator (SBP) 2 according to the embodiments of this disclosure. [Figure 15] Figure 15 shows the hydrogen nuclear magnetic resonance spectrum of initiator (SBP) 2 according to an embodiment of the present disclosure. [Figure 16] Figure 16 shows the mass spectrum of initiator (SBP) 2 according to the embodiments of this disclosure. [Figure 17] Figure 17 shows the structural formula of initiator (SBP) 3 according to the embodiments of this disclosure. [Figure 18] Figure 18 shows the hydrogen nuclear magnetic resonance spectrum of initiator (SBP) 3 according to an embodiment of the present disclosure. [Figure 19] Figure 19 shows the mass spectrum of initiator (SBP) 3 according to the embodiments of this disclosure. [Figure 20] Figure 20 shows the ultraviolet absorption spectra of initiators SBP, (SBP)2, and (SBP)3 according to the embodiments of this disclosure. [Figure 21] Figure 21 shows a schematic diagram of the molecular structure of an initiator having multiple initiation sites according to an embodiment of the present disclosure. [Figure 22] Figure 22 shows the structural formula of the initiator according to the embodiments of this disclosure. [Figure 23] Figure 23 shows the structural formula of the initiator according to the embodiments of this disclosure. [Figure 24] Figure 24 shows the synthesis steps of the initiator according to the embodiments of this disclosure. [Figure 25] Figure 25 shows a schematic diagram of the principle of improving the starting rate using a mixture of benzophenone and amine compounds provided in the embodiments of this disclosure. [Figure 26] Figure 26 shows a schematic diagram of the principle of improving the starting rate using a mixture of benzophenone derivatives and amine compounds provided in the embodiments of this disclosure. [Figure 27] Figure 27 shows the structural formula of a ligand on the surface of a quantum dot according to an embodiment of the present disclosure. [Figure 28] Figure 28 shows a flowchart of a method for manufacturing a patterned quantum dot light-emitting layer according to an embodiment of the present disclosure. [Figure 29] Figure 29 shows a schematic diagram of a method for manufacturing a patterned quantum dot light-emitting layer according to an embodiment of the present disclosure. [Figure 30] Figure 30 shows a schematic diagram of the mechanism of polymerization initiation of quantum dot ligands by the initiator SBP according to the embodiments of this disclosure. [Figure 31] Figure 31 shows a schematic diagram of the mechanism of polymerization initiation of quantum dot ligands by initiator (SBP) 2 according to the embodiments of this disclosure. [Figure 32] Figure 32 shows a schematic diagram of the mechanism of polymerization initiation of quantum dot ligands by initiator (SBP) 3 according to the embodiments of this disclosure. [Figure 33] Figure 33 shows the electron paramagnetic resonance spectrum of a quantum dot emissive layer containing initiators SBP, (SBP)2, and (SBP)3 according to an embodiment of the present disclosure. [Figure 34] Figure 34 shows the effect of exposure dose on the residual film rate of the quantum dot emissive layer of different initiators SBP, (SBP)2, and (SBP)3 according to the embodiments of this disclosure. [Figure 35] Figure 35 shows scanning electron microscope images and atomic force microscope images of a quantum dot light-emitting layer according to an embodiment of the present disclosure. [Figure 36] Figure 36 shows the relationship between the concentration of initiator (SBP) 3 and the thickness of the quantum dot light-emitting layer in the embodiments of this disclosure. [Figure 37] Figure 37 shows fluorescence microscope images of quantum dot emissive layers containing different concentrations of initiator (SBP) 3 according to embodiments of this disclosure. [Figure 38] Figure 38 shows a photograph of a patterned red-green-blue quantum dot emitting layer on a backplane having different pixel densities according to an embodiment of the present disclosure. [Figure 39] Figure 39 shows the effect of the concentration of initiator (SBP) 3 in the embodiments of this disclosure on the current efficiency of the light-emitting device. [Figure 40] Figure 40 shows the effect of the concentration of initiator (SBP) 3 in the embodiments of this disclosure on the external quantum efficiency of the light-emitting device. [Figure 41] Figure 41 shows a schematic diagram of the structure of a light-emitting device according to an embodiment of the present disclosure. [Figure 42] Figure 42 shows a fluorescence microscope image of a quantum dot light-emitting layer according to an embodiment of the present disclosure. [Figure 43] Figure 43 shows the spectral diagram of an electrical excitation of a light-emitting device according to an embodiment of the present disclosure. [Figure 44] Figure 44 shows a block diagram of a display device according to an embodiment of the present disclosure.

[0027] As should be understood, the drawings are merely schematic diagrams of exemplary embodiments of the present disclosure and do not limit the disclosure, and are not necessarily drawn to scale. In addition, identical or similar components are denoted by the same or similar reference numerals in the drawings. [Modes for carrying out the invention]

[0028] The technical solutions of the embodiments of this disclosure will be clearly described below with reference to the drawings of the embodiments of this disclosure. As will be obvious, the embodiments described are only a selection of the embodiments of this disclosure, not all of them. All other embodiments obtained by a person skilled in the art without requiring any creative work based on the embodiments of this disclosure are all within the scope of this disclosure.

[0029] Before formally describing the technical solutions of the embodiments of this disclosure, the following interpretations and definitions of terms used in the embodiments of this disclosure are provided so that those skilled in the art may better understand the technical solutions of the embodiments of this disclosure.

[0030] As used herein, the term “initiator” refers to a compound that is readily decomposed into radicals under specific conditions (e.g., light irradiation) and can be used to initiate radical polymerization and copolymerization reactions of olefinic and diene monomers, and can also be used in crosslinking curing and polymeric crosslinking reactions of unsaturated polyesters.

[0031] As used herein, the terms "tertiary amine" or "tertiary amine group" refer to amines in which a trivalent group bonded to three hydrocarbon groups exists in the molecule or group. The general structural formula of a tertiary amine is: [ka] The hydrocarbon group R may have any suitable number of carbon atoms.

[0032] Quantum dot light-emitting diode (LED) displays are a novel display technology developed based on organic light-emitting diode (OLED) displays. Quantum dot LED displays use a quantum dot emissive layer as the light-emitting layer. Their light-emitting principle involves injecting holes and electrons into the quantum dot emissive layer via hole transport and electron transport layers, respectively. The holes and electrons then recombine within the quantum dot emissive layer, thereby achieving light emission. Compared to organic LED displays, quantum dot LED displays offer advantages such as higher color saturation, a wider color gamut, a narrower emission peak, and better stability. With the significant advancements in quantum dot technology, research based on quantum dot displays is becoming increasingly in-depth, and with the continuous improvement of quantum efficiency, a basic level of industrialization can be achieved. Therefore, developing new processes and technologies for manufacturing quantum dot emissive layers to improve the manufacturing process of quantum dot LED displays is a future trend.

[0033] Conventional methods for patterning quantum dot emissive layers involve exposing and developing a photoresist layer to obtain a patterned photoresist. Next, the patterned photoresist is used to shield the quantum dot emissive layer, etching away unwanted areas and thereby forming the patterned quantum dot emissive layer. While conventional photoresist methods can achieve quantum dot patterning, their complex process flow and poor solvent compatibility limit their further application. To address these limitations, the development of new quantum dot patterning methods is urgently needed.

[0034] Recently, the industry has proposed that a patterned quantum dot emissive layer can be obtained by directly exposing and developing quantum dot films without using photoresists. Such a manufacturing method is simple, low-cost, and can produce high-quality patterned quantum dot emissive layers, thereby enabling higher-resolution quantum dot light-emitting diode display devices. When patterning is achieved by directly photoetching the quantum dot emissive layer, it is necessary to add an initiator to the quantum dot solution and cause a photosensitization reaction between the initiator and ligands on the quantum dot surface to form a patterned quantum dot emissive layer. The reaction activity between the initiator and the ligands on the quantum dot surface determines the stability of the patterned quantum dot emissive layer. Therefore, the development of highly active initiators is crucial for direct patterning methods of quantum dot emissive layers.

[0035] In related technologies, benzophenone can be used as an initiator. Figure 1 shows a schematic diagram of the photoinitiated radical polymerization mechanism of benzophenone. As shown in Figure 1, benzophenone transitions to a singlet excited state after irradiation, and then undergoes an internal transition to a more stable triplet excited state. Subsequently, the triplet excited benzophenone abstracts a hydrogen atom from the molecular chain PH, converting the molecular chain PH into a radical P·, and the benzophenone from which the hydrogen atom has been abstracted becomes semibenzopinacol. [ka] This is abbreviated as K·. The two semibenzopinacol K· can recombine to benzopinacol KK, which is a photodegradation product of benzophenone, and at the same time, the two radicals P· from the reaction can form a crosslink bond PP.

[0036] Furthermore, the P· radical can also initiate radical polymerization of carbon-carbon double bonds. As shown in Figure 2, the activity of the P· radical is transferred to monomer M, forming a monomer radical M·. Similarly, the monomer radical M· continues to initiate polymerization of the monomer to form a polymer. As the reaction progresses, the chain length increases, the activity of the monomer radical decreases, which causes chain transfer, transferring activity to the monomer and forming a new active site, thereby achieving chain elongation.

[0037] However, the inventors of this application have found that the polymerization rate of monomers initiated by benzophenone is relatively slow, which may be because triplet-state benzophenone is easily quenched by oxygen in the air, thereby weakening its polymerization activity. Therefore, when the polymerization reaction of ligands on the quantum dot surface is initiated using benzophenone as an initiator, the slow initiation rate does not contribute to improving production efficiency, and thus production costs increase significantly.

[0038] In view of this, some embodiments of the present disclosure provide initiators that can improve the activity and stability of radicals and significantly improve the initiation efficiency, thereby helping to efficiently form high-quality patterned quantum dot emissive layers, and helping to improve production efficiency and reduce production costs.

[0039] Figure 3 shows the structural formula of the initiator provided by the embodiments of this disclosure. The structural formula is [ka] The following is abbreviated as structural formula (1). In structural formula (1), R11, R12, R13, R14, and R15 may be the same or different from each other, and each of R11, R12, R13, R14, and R15 may be one selected from a hydrogen atom, a group containing a nitrogen atom and a hydrogen atom, an ester group, and an alkyl group; R21, R22, R23, and R24 may be the same or different from each other, and each of R21, R22, R23, and R24 may be one selected from a hydrogen atom, a fluorine atom, a sulfur atom, an oxygen atom, an ester group, an alkyl group, and a group containing a nitrogen atom and a hydrogen atom; and R3 may be one selected from a sulfur atom, an oxygen atom, an ester group, an amide group, an alkyl group, a hydrogen atom, and a fluorine atom. There may be only one R4, and R4 may be one of the ester group, alkyl group, and group containing a nitrogen atom and a hydrogen atom; R31, R32, R33, R34, R35, R36, R37, R38, and R39 may or may not be present, and they may be the same or different from each other; if at least one of R31, R32, R33, R34, R35, R36, R37, R38, and R39 is present, it may be one of the ester group, alkyl group, and group containing a nitrogen atom and a hydrogen atom; n is a positive integer of 1 or more, and the initiator group must contain at least one of the sulfur atom, oxygen atom, and group containing a nitrogen atom and a hydrogen atom. Note that the term "initiator group" refers to any group other than the benzophenone skeleton, i.e., any one or more of R11-R15, R21-R24, R31-R39, R3, and R4.

[0040] In structural formula (1), the types of groups R11-R15, R21-R24, R31-R39, R3, and R4 can be flexibly combined according to the types described above, and the initiator groups only need to contain at least one of the groups containing a sulfur atom, an oxygen atom, a nitrogen atom, and a hydrogen atom.

[0041] The following describes why this initiator can improve the initiation rate.

[0042] The initiator was obtained by further designing and optimizing the molecular structure of benzophenone to form the above structural formula (1). As mentioned above, after irradiation, benzophenone eventually transitioned to a more stable triplet excited state, but the triplet state of benzophenone is easily quenched by oxygen in the air. However, in structural formula (1), the initiator's group contains at least one of the groups containing a sulfur atom, an oxygen atom, a nitrogen atom, and a hydrogen atom, and the introduction of these groups improves the initiator's initiation rate. The reason is as follows.

[0043] When the initiator group contains a group containing nitrogen and hydrogen atoms, this nitrogen and hydrogen atom-containing group can suppress the quenching of triplet-state benzophenone by oxygen (O2), and the mechanism is shown in Figure 4. In Figure 4, R· represents the triplet excited state to which structural formula (1) transitions after irradiation, and the molecule containing nitrogen and hydrogen atoms is [ka] Let's take this as an example. As shown in Figure 4, the triplet state R· has a long-lived triplet state, [ka] It readily extracts hydrogen atoms to form RH, and at the same time, it is an active amine radical. [ka] This generates the amine radicals produced [ka] It further reacts with O2 to form a peroxide. [ka] It can generate peroxides [ka] teeth [ka] By removing a hydrogen atom, another amine radical is created. [ka] Although it is possible to generate R· in the triplet state, oxygen did not consume the triplet state R· throughout the entire process. Therefore, if the initiator group contains a group containing a nitrogen atom and a hydrogen atom, the polymerization inhibitory effect of oxygen on the triplet state R· in the curing system can be eliminated. In addition, the generated active amine radical [ka] It exhibits low steric hindrance, high initiation activity, and can accelerate the initiation of polymerization reactions of carbon-carbon double bonds in ligands on quantum dot surfaces.

[0044] In the embodiments of this disclosure, the group containing a nitrogen atom and a hydrogen atom may be any suitable electron-donating group to provide the hydrogen atom. In some embodiments, the group containing a nitrogen atom and a hydrogen atom may be a pyrrole group or a tertiary amine group. Pyrrole or tertiary amines readily provide hydrogen atoms, thereby converting the group into a more active amine radical, which promotes the polymerization reaction of the carbon-carbon double bond of the ligand on the quantum dot surface. In some embodiments, the tertiary amine group may be a triethylamine group. In some embodiments, the number of hydrogen atoms in the group containing a nitrogen atom and a hydrogen atom may be 1 to 3.

[0045] The presence of sulfur or oxygen atoms in the initiator base is also advantageous for improving the initiator's initiation rate. Taking sulfur atoms as an example, they have an electron-rich effect, which is advantageous for improving the photosensitivity of the initiator. The reaction mechanism is shown in Figure 5. Under light irradiation, sulfur atoms cause the sulfur ether bond to break, generating sulfur radicals, benzene radicals, etc., thereby increasing the radical active center and improving the initiator's initiation rate. Furthermore, sulfur atoms are weak electron-donating groups, allowing the entire structural formula (1) to become a push-pull-push conjugated system, causing a clear redshift in the absorption of the initiator molecule. Oxygen atoms are also weak electron-donating groups and have a similar effect to sulfur atoms, so the presence of oxygen atoms in the initiator base can also improve the initiator's initiation rate.

[0046] As described above, if the group of structural formula (1) contains at least one of the groups containing sulfur atoms, oxygen atoms, nitrogen atoms, and hydrogen atoms, the initiator initiation rate can be improved. Accordingly, if the group of structural formula (1) contains at least two of the groups containing sulfur atoms, oxygen atoms, nitrogen atoms, and hydrogen atoms, the radical activity and stability can be greatly improved, thereby greatly improving the initiator initiation rate and further increasing the reactivity of quantum dots and initiators in the exposure area per unit time, which helps to form a high-quality patterned quantum dot emissive layer.

[0047] As mentioned above, in structural formula (1), n ​​is a positive integer greater than or equal to 1. In some embodiments, n is equal to 1. In this case, structural formula (1) is equivalent to optimizing the molecular structure of a single benzophenone, thereby improving the initiator initiation rate. In some alternative embodiments, n may be a positive integer greater than 1. In this case, structural formula (1) is equivalent to synthesizing multiple optimized benzophenone structural units into one molecule. In this way, multiple initiation sites can be simultaneously generated in one initiator molecule under exposure per unit time, thereby further improving the initiator initiation rate per unit time. Theoretically, a larger value of n results in more reaction sites for the initiator, which is advantageous for improving the initiator initiation rate. However, a larger value of n also leads to greater molecular steric hindrance of the initiator, making the synthesis and purification of the initiator difficult. Therefore, it is preferable not to set the value of n too high. In some embodiments, the value of n may be a positive integer between 1 and 10. In some embodiments, the value of n may be a positive integer between 1 and 6.

[0048] Figure 6 shows an example where n is greater than 1, and for example, the initiator may contain 4, 6, or 10 optimized benzophenone structural units. In some embodiments, the initiator may be designed in polymer form.

[0049] As mentioned above, groups R31 to R39 in structural formula (1) may or may not be present. Since the type of groups R31 to R39 is the same as the type of group R4, if at least one of groups R31 to R35 is present, it can be understood that group R4 can also bond to at least one of groups R11 to R15, and if at least one of groups R36 to R39 is present, it can be understood that group R4 can also bond to at least one of groups R21 to R24.

[0050] In some embodiments, none of the groups R31 to R39 in structural formula (1) are present. In this case, structural formula (1) [ka] This can be simplified to structural formula (2), which will be abbreviated as structural formula (2) below and is shown in Figure 7. In structural formula (2), R11, R12, R13, R14, and R15 may each be selected from a hydrogen atom or a group containing a nitrogen atom and a hydrogen atom, R21, R22, R23, and R24 may each be selected from a hydrogen atom or a fluorine atom, R3 may be any one selected from a sulfur atom, an oxygen atom, an ester group, an amide group, and an alkyl group, and R4 may be any one selected from an ester group, an alkyl group, and a group containing a nitrogen atom and a hydrogen atom, and n is a positive integer of 1 or more. Similarly, the group in structural formula (2) must contain at least one of a sulfur atom, an oxygen atom, or a group containing a nitrogen atom and a hydrogen atom.

[0051] In some examples, in structural formula (2), n is equal to 1, R11 is a pyrrole group, R12, R13, R14, and R15 are all hydrogen atoms, R21 to R24 are all hydrogen atoms, R3 is a sulfur atom, and R4 is an ester group, that is, structural formula (2) is specifically [ka] It is abbreviated as SBP.

[0052] The following describes the synthesis steps of the initiator SBP using one example.

[0053] As shown in Figure 8, a certain amount of 4,4-difluorobenzophenone (e.g., about 218.2 mg) and tetrahydropyrrole (e.g., about 71.2 mg) are mixed, an appropriate amount of dimethyl sulfoxide DMSO (e.g., about 6 mL) is added, and the mixture is reacted at 60°C for about 6 hours. Next, the reaction solution is poured into 100 mL of water, filtered by suction, and a solid powder is obtained. The solid powder is washed with methanol to remove the starting material 4,4-difluorobenzophenone from the solid powder, and the intermediate product is obtained. [ka] The intermediate product obtained is abbreviated as NBP-F.

[0054] As shown in Figure 9, a certain amount of NBP-F (e.g., about 270 mg) and ethyl thioglycolate (e.g., about 120 mg) are mixed, and an appropriate amount of NaH (e.g., about 24 mg) and anhydrous DMF (e.g., about 10 mL) are added. The mixture is heated at 60°C and reacted for 8 hours. Next, the reaction solution is poured into 100 mL of water, filtered by suction, and a solid powder is obtained. The solid powder is purified by column chromatography to obtain the target product, SBP. The developing solvents used in column chromatography are dichloromethane and ethyl acetate, and the mixing ratio of the two may be 10:1.

[0055] Figure 10 shows the hydrogen nuclear magnetic resonance spectrum of SBP, and Figure 11 shows the mass spectrum of SBP. The hydrogen nuclear magnetic resonance spectrum and mass spectrum prove that the synthetic structure of SBP is accurate.

[0056] The synthesis steps for SBP are relatively simple, and the process is easy to implement. In the molecular structure of SBP, group R11 is selected as a pyrrole group. As mentioned above, the pyrrole group is an electron-donating group that readily provides hydrogen atoms, eliminating the polymerization inhibitory effect of oxygen on the triplet state benzophenone structural unit in the curing system under light irradiation. Furthermore, the generated active amine radical has low steric hindrance and high initiation activity, accelerating the initiation of the polymerization reaction of the carbon-carbon double bond of the ligand on the quantum dot surface. Group R3 is selected as an S atom. As mentioned above, the S atom generates S radicals under light irradiation, increasing the concentration and variety of radicals per unit time, thereby accelerating the polymerization rate of radicals per unit time. By simultaneously introducing the pyrrole group and S atom into the initiator SBP, the initiation rate of the initiator SBP can be significantly improved. In addition, since group R3 is positioned in the para position relative to C=O, the synthesis of SBP is facilitated. The R4 group was selected as an ester group, which can enhance the compatibility between the initiator SBP and the quantum dot solvent, thereby resulting in superior stability of the material system.

[0057] In some embodiments, further synthesis is performed based on SBP. [ka] This product, abbreviated as SBP-COOH, can be obtained. The synthesis steps for SBP-COOH involve mixing a certain amount of SBP (e.g., about 408 mg) with NaOH (e.g., about 0.04 mg), adding an appropriate amount of acetone (e.g., about 10 mL), and reacting at 40°C for 4 hours. Next, the acetone is evaporated to dryness to obtain a yellow solid. The yellow solid is washed three times with water to remove the NaOH. After drying, the target product SBP-COOH is obtained.

[0058] Figure 12 shows the hydrogen nuclear magnetic resonance spectrum of SBP-COOH, and Figure 13 shows the mass spectrum of SBP-COOH. The hydrogen nuclear magnetic resonance spectrum and mass spectrum prove that the synthetic structure of SBP-COOH is accurate.

[0059] In some alternative embodiments, in structural formula (2), n is equal to 2, R11 is a pyrrole group, R12, R13, R14, and R15 are all hydrogen atoms, R21 to R24 are all hydrogen atoms, R3 is a sulfur atom, and R4 is an ester group. That is, structural formula (2) is specifically [ka] This is abbreviated as (SBP)2, as shown in Figure 14.

[0060] The following describes the synthesis steps of initiator (SBP) 2 using one example.

[0061] A certain amount of SBP-COOH (e.g., about 340 mg), ethylene glycol (e.g., about 62 mg), 1-ethyl-(3-dimethylaminopropyl)carbodiimide (abbreviated as EDC, e.g., about 150 mg), 4-dimethylaminopyridine (abbreviated as DMAP, e.g., about 50 mg), and dichloromethane (e.g., about 10 mL) are mixed and dissolved, and the mixture is reacted at room temperature for 12 hours. The mixture is purified by column chromatography to obtain the target product (SBP) 2. Dichloromethane is used as the developing solvent in the column chromatography method.

[0062] Figure 15 shows the hydrogen nuclear magnetic resonance spectrum of (SBP)2, and Figure 16 shows the mass spectrum of (SBP)2. The relative molecular weight of (SBP)2 is 708, and in Figure 16, two peaks are shown at 731 and 709, respectively. These two peaks correspond to the relative molecular weight of (SBP)2 + Na (731) and the relative molecular weight of (SBP)2 + H (709), respectively, indicating that the synthetic structure of (SBP)2 is accurate.

[0063] In addition to the technical effects of initiator SBP, initiator (SBP)2 has more initiation sites compared to initiator SBP, and therefore the initiation rate of initiator (SBP)2 per unit time is faster, which helps to further enhance the crosslinking effect of quantum dots.

[0064] In some other alternative embodiments, in structural formula (2), n is equal to 3, R11 is a pyrrole group, R12, R13, R14, and R15 are all hydrogen atoms, R21 to R24 are all hydrogen atoms, R3 is a sulfur atom, and R4 is an ester group, that is, structural formula (2) is specifically [ka] It is abbreviated as (SBP)3, and the structural formula of (SBP)3 is shown in Figure 17.

[0065] The following describes the synthesis steps of initiator (SBP) 3 using one example.

[0066] A certain amount of SBP-COOH (e.g., approximately 510 mg), glycerin (e.g., approximately 62 mg), EDC (e.g., approximately 200 mg), DMAP (e.g., approximately 70 mg), and dichloromethane (e.g., approximately 10 mL) are mixed and dissolved, and the mixture is reacted at room temperature for 12 hours. The mixture is purified by column chromatography to obtain the target product (SBP) 3. Dichloromethane is used as the developing solvent in the column chromatography method.

[0067] Figure 18 shows the hydrogen nuclear magnetic resonance spectrum of (SBP)3, and Figure 19 shows the mass spectrum of (SBP)3. In Figure 18, the two wave peaks marked "1" represent the group marked "1" in the molecular structure (SBP)3, the wave peak marked "2" represents the group marked "2" in the molecular structure (SBP)3, the wave peak marked "3" represents the group marked "3" in the molecular structure (SBP)3, the wave peak marked "4" represents the group marked "4" in the molecular structure (SBP)3, and the wave peak marked "5" represents the group marked "5" in the molecular structure (SBP)3. The relative molecular weight of (SBP)3 is 1098, and the peak value of one wave peak shown in Figure 19 is 1098. Figures 18 and 19 prove that the synthetic structure of (SBP)3 is accurate.

[0068] In addition to the technical effects of initiator SBP, initiator (SBP)3 has more initiation sites compared to initiator SBP and (SBP)2, and therefore the initiation rate of initiator (SBP)3 per unit time is faster, thereby resulting in a better crosslinking effect of quantum dots.

[0069] Figure 20 shows the ultraviolet absorption spectra of the three initiators SBP, (SBP)2, and (SBP)3. As shown in Figure 20, under the same solubility (0.01 mg / mL), all three initiators show strong absorption at 365 nm, with (SBP)3 having the strongest absorption intensity, followed by (SBP)2, and SBP having the weakest absorption intensity.

[0070] In initiators SBP, (SBP)2, and (SBP)3, a pyrrole group and a sulfur atom are introduced simultaneously. Thus, on the one hand, under light irradiation, the initiator can abstract a hydrogen atom from the pyrrole group, thereby converting the pyrrole group into an active amine radical. The resulting amine radical can react with oxygen to produce a peroxide, which can then abstract another hydrogen atom, further generating other amine radicals. Oxygen does not consume the triplet state benzophenone structural unit throughout the entire process. Therefore, introducing the pyrrole group eliminates the polymerization inhibitory effect of oxygen on radical polymerization reactions in the system. Furthermore, the active amine radical has low steric hindrance and high initiation activity, accelerating the initiation of the polymerization reaction of carbon-carbon double bonds of ligands on the quantum dot surface. On the other hand, under light irradiation, the sulfur atom can cause the sulfur ether bond to break, generating sulfur radicals, benzene radicals, etc., increasing the number of radical active centers. Moreover, since the sulfur atom is a weak electron-donating group, the entire molecular structure of the initiator becomes a push-pull-push conjugated system, causing a clear redshift in the absorption of the entire molecule. Therefore, by simultaneously introducing a pyrrole group and a sulfur atom into the molecular structure, the activity and stability of the radical can be greatly improved, thereby significantly increasing the initiator's initiation rate and further increasing the reactivity between the quantum dot and the initiator within the exposure area per unit time, which helps in forming a high-quality patterned quantum dot emissive layer. Group R4 is selected as an ester group, which can enhance the compatibility between the initiator SBP and the quantum dot solvent, thereby providing excellent stability to the material system.

[0071] In some other embodiments, in structural formula (2), n is equal to 4, R11 is a pyrrole group, R12, R13, R14, and R15 are all hydrogen atoms, R21 to R24 are all hydrogen atoms, R3 is a sulfur atom, and R4 is an ester group, that is, structural formula (2) is specifically [ka] It is abbreviated as (SBP)4.

[0072] In some embodiments, in structural formula (2), n may be a larger positive integer, for example, n may be 5, 6, 10, or a larger positive integer, as shown in Figure 21. In this way, by introducing multiple benzophenone units based on the optimized benzophenone molecule, the number of initiation sites can be increased, the initiation rate of the initiator per unit time can be increased, thereby ensuring a higher degree of photopolymerization of the initiator with the same amount of light irradiation, further improving the photopatterning effect of the initiator and enhancing the crosslinking effect of the quantum dots.

[0073] Figure 22 shows the structural formula of the initiator. [ka] This shows that n is a positive integer greater than or equal to 1. If n is equal to 1, then SBP is true; if n is equal to 2, then (SBP)2; and if n is equal to 3, then (SBP)3.

[0074] In the above examples, the case where the group containing a nitrogen atom and a hydrogen atom is a pyrrole group was described. In some alternative examples, the group containing a nitrogen atom and a hydrogen atom may be a tertiary amine group.

[0075] Figure 23 is the structural formula [ka] This is shown and abbreviated as structural formula (3). That is, when R11 in structural formula (2) is a tertiary amine group, R12, R13, R14, and R15 are all hydrogen atoms, R21 to R24 are all hydrogen atoms, R3 is a sulfur atom, and R4 is an ester group, structural formula (2) is represented as structural formula (3). In structural formula (3), x and y are both positive integers of 1 or more. Since both the tertiary amine group and the pyrrole group readily provide hydrogen atoms, the initiator [ka] is the initiator [ka] It has a similar technical effect, and for the sake of brevity, here [ka] The technical effects are not explained repeatedly.

[0076] In some embodiments, the number of carbon atoms in the branched chain bonded to the N atom in structural formula (3) may be 2 to 30, for example, 2, 3, 6, 9, 16, 20, 30, etc.

[0077] Figure 24 shows the initiator. [ka] The synthesis steps for (i.e., when n=1 in structural formula (3)) are shown. As shown in Figure 24, 4,4-difluorobenzophenone and a tertiary amine [ka] Mix the ingredients, add appropriate amounts of NaH and anhydrous DMF, and react at 60°C for a certain period of time to obtain an intermediate product. [ka] Next, the intermediate product is mixed with ethyl thioglycolate and reacted to obtain the product. [ka] Generates.

[0078] [ka] The synthesis steps are relatively simple, and the process is easy to implement. In the molecular structure, group R11 is selected as a tertiary amine group. As mentioned above, the tertiary amine group is an electron-donating group, readily provides hydrogen atoms, and can eliminate the polymerization inhibitory effect of oxygen on the triplet state benzophenone structural unit in the curing system under light irradiation. Furthermore, the generated active amine radical has low steric hindrance and high initiation activity, which can accelerate the initiation of the polymerization reaction of the carbon-carbon double bond of the ligand on the quantum dot surface. Group R3 is selected as an S atom. As mentioned above, the S atom generates S radicals under light irradiation, which can increase the concentration and variety of radicals per unit time, thereby accelerating the polymerization rate of radicals per unit time. By simultaneously introducing a tertiary amine group and an S atom into the initiator, the initiation rate of the initiator can be greatly improved. In addition, since the S atom is positioned in the para position relative to C=O, the synthesis of the initiator is facilitated. Group R4 was selected as an ester group, which can enhance the compatibility between the initiator and the quantum dot solvent, thereby resulting in superior stability of the material system.

[0079] Other aspects of the present disclosure provide alternative initiators, which are mixtures of benzophenone and an amine compound, or mixtures of a benzophenone derivative and an amine compound, and which have similar technical effects to the initiators described in the above examples and can also improve the rate of initiation.

[0080] In some embodiments, the amine compound may be a tertiary amine or pyrrole, and benzophenone or a benzophenone derivative readily abstracts hydrogen atoms from the tertiary amine or pyrrole, thereby forming a more active amine radical. The structural formula of the benzophenone derivative is [ka] Here, R0 is one of the elements selected from O, S, C6H5, OH, Br, Cl, and I, and m is a positive integer greater than or equal to 0.

[0081] Figure 25 shows a schematic diagram illustrating the principle of improving the initiator initiation rate by mixing benzophenone and an amine compound, and Figure 26 shows a schematic diagram illustrating the principle of improving the initiator initiation rate by mixing a benzophenone derivative and an amine compound. The amine compound is a tertiary amine. [ka] This is explained as an example, but this is merely one example of an amine compound and does not limit the types of amine compounds. As mentioned above, benzophenone transitions under light irradiation to form triplet benzophenone, but triplet benzophenone is easily quenched by O2 in the air, and its polymerization activity is weakened. However, in the examples of this disclosure, as shown in Figures 25 and 26, benzophenone and amine compound [ka] By mixing these, an improved initiator is formed, or a benzophenone derivative and an amine compound [ka] By mixing these, an improved initiator is formed, and under light irradiation, electron transfer occurs between the benzophenone and amine compounds, resulting in highly active amine radicals. [ka] and inert [ka] Alternatively, electron transfer occurs between the benzophenone derivative and the amine compound, resulting in highly active amine radicals. [ka] and inert [ka] This generates a highly active amine radical. The activity of the highly active amine radical is not quenched by O2 in the air and can maintain relatively high activity with O2, thereby initiating polymerization of the carbon-carbon double bond of the quantum dot ligand. Therefore, initiators formed by mixing an amine compound with benzophenone or a benzophenone derivative can eliminate the polymerization inhibitory effect of O2 on radical polymerization reactions in the curing system, promoting polymerization of quantum dot ligands and helping to form a high-quality patterned quantum dot luminescent layer.

[0082] In some examples, tertiary amines are used. [ka] The group Rx includes, but is not limited to, H, CH3, CH2CH3, etc. For example, [ka] It may also be triethylamine.

[0083] In some embodiments, the molar ratio of benzophenone or benzophenone derivative to tertiary amine in the mixture may be 1:1. After irradiation with light, the benzophenone or benzophenone derivative in the mixture abstracts hydrogen atoms from the tertiary amine, and one benzophenone molecule or one benzophenone derivative molecule can satisfy the electron transfer needs between them with only one tertiary amine molecule.

[0084] According to another aspect of this disclosure, a quantum dot having ligands on its surface is provided, and Figure 27 shows the structural formula of the ligand on the quantum dot surface. [ka] This is shown and will be abbreviated as structural formula (4) below. In structural formula (4), R5 is coordinately bonded to the surface of the quantum dot and is selected from a mercapto group, a carboxyl group, or an amino group, R6 is selected from an ester group or an ether group, and R7 is selected from an ester group or an ether group. The ligand on the surface of the quantum dot can undergo a chemical reaction with the initiator described in any of the above examples under light irradiation.

[0085] Organic ligands on the quantum dot surface can compensate for defects on the quantum dot surface, thereby improving the stability and quantum yield of the quantum dots. The initiators provided by the embodiments of this disclosure are radical photoinitiators that can initiate polymerization reactions of carbon-carbon double bonds. To realize the photopatterning effect of quantum dots, the ligands on the quantum dot surface must contain carbon-carbon double bonds. In some embodiments, the number of carbon-carbon double bonds in the ligand is one. In some embodiments, the number of carbon-carbon double bonds in the ligand may be 2 to 4 to increase the degree of crosslinking. However, too many carbon-carbon double bonds in the ligand can adversely affect the colloidal stability of the quantum dot itself.

[0086] Furthermore, the ligand group R5 needs to coordinate with the defect state of the quantum dot; therefore, R5 needs to contain a functional group such as a mercapto group, a carboxyl group, or an amino group. Also, considering that the ligand of the quantum dot contains a carbon-carbon double bond, in order to improve the compatibility between the initiator and the solvent of the quantum dot, the ligand of the quantum dot needs to further contain functional groups such as an ester group or an ether group, i.e., groups R6 and R7, thereby improving the mutual solubility of the quantum dot and the initiator in the solvent.

[0087] In some examples, group R5 of the quantum dot ligand is a carboxyl group, and groups R6 and R7 are ester groups, in which case the structural formula (4) of the quantum dot ligand is [ka] This is abbreviated as MMES. Quantum dots having the ligand MMES exhibit good dispersibility in propylene glycol monomethyl ether acetate (abbreviated as PGMEA) solvent, and for example, solubility can exceed 60 mg / mL.

[0088] In the structural formula (4) of the quantum dot ligand, the carbon-carbon double bond is designed to be located at the end of the molecular chain, thus helping to reduce steric hindrance in radical polymerization and improve the activity of radical polymerization.

[0089] In some embodiments, the number of carbon atoms in the structural formula (4) of the quantum dot ligand ranges from 2 to 30, for example, 2, 5, 10, 16, 20, 25, 30, etc.

[0090] The quantum dots provided by the embodiments of this disclosure may be any suitable quantum dot, including, but not limited to, one of the following: IIB-VIA quantum dots, IIIA-VA quantum dots, IVA-VIA quantum dots, core-shell quantum dots, perovskite quantum dots, nanorods, nanosheets, or cadmium (Cd)-free quantum dots.

[0091] Figure 28 shows a flowchart of a method 100 for manufacturing a patterned quantum dot light-emitting layer. As shown in Figure 28, the method 100 includes steps S101 to S103.

[0092] S101: Provides a circuit board.

[0093] The substrate may be an inorganic material, an organic material, a silicon wafer, or a composite material layer. Examples of inorganic materials include glass, metal, etc., and examples of organic materials include polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyethersulfone, or combinations thereof.

[0094] S102: A mixed solution is applied to a substrate, the mixed solution comprising quantum dots and an initiator, the surface of the quantum dots having ligands containing carbon-carbon double bonds, and the initiator group comprising at least one of groups containing sulfur atoms, oxygen atoms, nitrogen atoms and hydrogen atoms.

[0095] The quantum dot may be any of the quantum dots described in any of the above examples, and the initiator may be any of the initiators described in any of the above examples.

[0096] In some embodiments, the concentration of quantum dots in the mixed solution may be approximately 25-30 mg / mL, for example 25 mg / mL, 27.5 mg / mL, 30 mg / mL, etc., and the concentration of the initiator in the mixed solution may be approximately 0.1-1.0 mg / mL, for example 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL, 0.5 mg / mL, 0.6 mg / mL, 0.7 mg / mL, 0.8 mg / mL, 0.9 mg / mL, 1.0 mg / mL, etc.

[0097] S103: Under light irradiation, the initiator initiates a polymerization reaction of the ligand's carbon-carbon double bond, forming a patterned quantum dot luminescent layer.

[0098] In the method 100, an initiator and a quantum dot ligand undergo a photosensitization reaction to form a patterned quantum dot emissive layer. The reaction activity between the initiator and the quantum dot ligand determines the stability of the patterned quantum dot emissive layer. In the embodiments of this disclosure, the initiator molecule is designed and optimized so that the initiator group contains at least one of groups containing a sulfur atom, an oxygen atom, a nitrogen atom, and a hydrogen atom, thereby improving the initiation rate per unit time and making the radical activity more stable, thereby increasing the degree of photoreaction between the quantum dots and the initiator in the exposed area and reducing the exposure amount, which helps to form a high-quality patterned quantum dot emissive layer.

[0099] The quantum dots provided by the embodiments of this disclosure are negative colloidal quantum dot materials. Specifically, in the manufacturing process, a mixed solution containing quantum dots and an initiator is cured into a film, and under light irradiation, the chemical composition of the exposed portion of the film layer changes, but the chemical composition of the unexposed portion remains unchanged. The unexposed portion of the film layer can then be dissolved in a specific developer, but the exposed portion does not dissolve in the developer, thereby forming a patterned quantum dot light-emitting layer. Therefore, a patterned quantum dot light-emitting layer can be obtained by directly exposing and developing a photosensitive quantum dot film during manufacturing, eliminating the need to use photoresist and the need to etch the quantum dot light-emitting layer.

[0100] Figure 29 shows a schematic diagram of the method for manufacturing a patterned quantum dot emissive layer. The steps of Method 100 will be described in detail below with reference to Figure 29.

[0101] First, a first mixed solution containing a first quantum dot and an initiator is coated onto the substrate. Then, the first mixed solution coated on the substrate is cured to form a first intermediate film layer.

[0102] Next, the mask plate 201 is aligned with the substrate, exposing the first target region to the mask plate 201 while shielding other non-target regions, and the first intermediate film layer is irradiated with light of a specific wavelength (e.g., ultraviolet light). Under light irradiation, the initiator initiates the polymerization reaction of the carbon-carbon double bonds of the ligands on the quantum dot surface, thereby changing the chemical composition of the portion of the first intermediate film layer exposed by the mask plate 201 under light irradiation.

[0103] Subsequently, the first intermediate film layer after exposure is developed using a developer solution. The portion of the first intermediate film layer located within the non-target region is dissolved by the developer solution, while the portion located within the first target region of the first intermediate film layer is not dissolved and remains. After development is complete, processes such as thermal baking or annealing can be performed to obtain a first quantum dot light-emitting layer patterned within the first target region. Exemplarily, the first quantum dot light-emitting layer can be used to emit red light.

[0104] By repeating the above operations, a patterned second quantum dot light-emitting layer and a third quantum dot light-emitting layer can be obtained, respectively. Specifically, a second mixed solution containing second quantum dots and an initiator is coated onto a substrate on which the first quantum dot light-emitting layer is formed. The second mixed solution applied to the substrate is cured to form a second intermediate film layer. Next, a mask plate 201 is aligned with the substrate, the second target region is exposed on the mask plate 201 and other non-target regions are shielded, and the second intermediate film layer is irradiated with light of a specific wavelength (e.g., ultraviolet light). Under light irradiation, the initiator initiates a polymerization reaction of the carbon-carbon double bonds of the ligands on the quantum dot surface, thereby changing the chemical composition of the portion of the second intermediate film layer exposed by the mask plate 201 under light irradiation. Subsequently, the exposed second intermediate film layer is developed using a developer, the portion located within the non-target region of the second intermediate film layer is dissolved by the developer, and the portion located within the second target region of the second intermediate film layer is not dissolved by the developer and remains. After development is complete, processes such as thermal baking and annealing can be performed to obtain a patterned second quantum dot light-emitting layer within the second target region. Exemplarily, the second quantum dot light-emitting layer can be used to emit green light. Next, a third mixed solution containing a third quantum dot and an initiator is coated onto the substrate on which the first and second quantum dot light-emitting layers are formed. The third mixed solution applied to the substrate is cured to form a third intermediate film layer. Next, a mask plate 201 is aligned with the substrate, exposing the third target region to the mask plate 201 while shielding other non-target regions, and the third intermediate film layer is irradiated with light of a specific wavelength (e.g., ultraviolet light). Under light irradiation, the initiator initiates polymerization reactions of the carbon-carbon double bonds of ligands on the quantum dot surface, thereby changing the chemical composition of the portion of the third intermediate film layer exposed by the mask plate 201 under light irradiation. Subsequently, the third intermediate film layer is developed using a developer solution. The portion of the third intermediate film layer located within the non-target region is dissolved by the developer solution, while the portion located within the third target region of the third intermediate film layer is not dissolved by the developer solution and remains intact.After development is complete, processes such as thermal baking and annealing can be performed to obtain a patterned third quantum dot emissive layer within the third target region. Exemplarily, the third quantum dot emissive layer can be used to emit blue light.

[0105] The initiator content in the first quantum dot light-emitting layer, the second quantum dot light-emitting layer, and the third quantum dot light-emitting layer may be the same or different.

[0106] The above method allows for the formation of a patterned red, green, and blue quantum dot light-emitting layer on a substrate. Compared to conventional methods for patterning quantum dot light-emitting layers using photoresist shielding, the quantum dot patterning method provided by the embodiments of this disclosure does not require photoresist, allows for direct exposure and development of the quantum dot film, has a simple process flow, and is free from problems such as solvent compatibility, resulting in a higher quality patterned quantum dot light-emitting layer. This patterning method helps to obtain quantum dot light-emitting diode devices with higher resolution and higher quality.

[0107] In some embodiments, the structural formula of the ligand on the quantum dot surface in the mixed solution is [ka] Therefore, it is MMES, the initiator in the mixed solution is SBP, and the structural formula of SBP is [ka] The structural formula of the quantum dot emissive layer formed by the initiator SBP and the ligand MMES is [ka] Here, QD represents a quantum dot, and k is a positive integer greater than or equal to 1.

[0108] Figure 30 illustrates the mechanism by which the initiator SBP initiates polymerization of ligands in quantum dots. As shown in Figure 30, the initiator SBP is more active when irradiated with ultraviolet light. [ka] It became, [ka] It is abbreviated as such. Under ultraviolet irradiation, [ka] It attacks the carbon-carbon double bond of a nearby ligand, thereby cleaving the carbon-carbon double bond. When the carbon-carbon double bond cleaved, two carbon radicals (C) are released. ● ) is formed, and one of the carbon radicals (C ● ) binds to the amine radical of the initiator SBP, and the other carbon radical (C ● ) then attacks the carbon-carbon double bond of the next adjacent ligand. When the carbon-carbon double bond of the next ligand is cleaved, a carbon radical (C) ● ) is also formed, and carbon radicals (C ● ) further attacks the carbon-carbon double bond of the next adjacent ligand. This continuous polymerization ultimately forms a crosslinked quantum dot luminescence layer. In Figure 30, the structural formula of the formed crosslinked quantum dot luminescence layer is [ka] The simplified structural formula is represented by the following formula. [ka]

[0109] In some alternative embodiments, the structural formula of the ligand on the quantum dot surface in the mixed solution is [ka] Therefore, it is MMES, and the initiator in the mixed solution is (SBP)2, and the structural formula of (SBP)2 is [ka] The structural formula of the quantum dot emissive layer formed by the initiator (SBP) 2 and the ligand MMES is [ka] Here, QD represents a quantum dot, and k is a positive integer greater than or equal to 1.

[0110] Figure 31 illustrates the mechanism by which initiator (SBP) 2 initiates polymerization of ligands in quantum dots. As shown in Figure 31, initiator (SBP) 2 is more active under ultraviolet irradiation. [ka] It became, [ka] It is abbreviated as [this]. The principle is similar to that shown in Figure 30, and under ultraviolet irradiation, [ka] The ligands on the quantum dot surface undergo polymerization reactions, ultimately forming a crosslinked quantum dot light-emitting layer. In Figure 31, the structural formula of the formed crosslinked quantum dot light-emitting layer is [ka] The simplified structural formula is represented by the following formula. [ka]

[0111] In some other alternative embodiments, the structural formula of the ligand on the quantum dot surface in the mixed solution is [ka] That is, it is MMES. The initiator in the mixed solution is (SBP)3, and the structural formula of (SBP)3 is [Chemical formula] The structural formula of the quantum dot light-emitting layer formed by the initiator (SBP)3 and the ligand MMES is [Chemical formula] where QD represents quantum dots and k is a positive integer greater than or equal to 1.

[0112] FIG. 32 exemplarily shows a mechanism diagram in which the initiator (SBP)3 starts the polymerization of quantum dot ligands. As shown in FIG. 32, the initiator (SBP)3 has higher activity [Chemical formula] under ultraviolet irradiation and becomes [Chemical formula] abbreviated as. Similar to the principle shown in FIG. 30, under ultraviolet irradiation, [Chemical formula] reacts with the ligands on the surface of the quantum dots through a polymerization reaction to finally form a crosslinked quantum dot light-emitting layer. In FIG. 32, the structural formula of the formed crosslinked quantum dot light-emitting layer is [Chemical formula] simplified to, and the simplified structural formula represents the following structural formula. [Chemical formula]

[0113] Figure 33 further confirms the mechanism of optical patterning of quantum dots by an electron paramagnetic resonance spectrum. As can be seen from the electron paramagnetic resonance spectrum, initiators SBP, (SBP)2, and (SBP)3 all generate strong radical signal peaks, indicating that the main mechanism of quantum dot patterning is that initiators SBP, (SBP)2, and (SBP)3 can initiate the radical polymerization of the carbon-carbon double bonds of quantum dot ligands.

[0114] Based on some experimental data, the initiator with the highest initiation effect can be selected from initiators SBP, (SBP)2, and (SBP)3.

[0115] First, the effect of the exposure dose of the initiator on the residual film rate is investigated. In the experiment, the ligand on the surface of the quantum dots can select MMES as described above, and the quantum dots with ligand MMES have good dispersibility in the PGMEA solvent (for example, the solubility is greater than 60 mg / mL). Initiators SBP, (SBP)2, and (SBP)3 also have good dispersibility in the PGMEA solvent (for example, the solubility is about 5 mg / mL).

[0116] First, a hole transport material is spin-coated on the substrate. The concentration of the hole transport material is, for example, 8 mg / mL, and the rotation speed of the spin coating is about 2000 rpm. Next, three mixed solutions containing quantum dots and initiators are spin-coated on the three substrates spin-coated with the hole transport material. The quantum dots in the three mixed solutions are all QD-MMES, the initiators in the three mixed solutions are SBP, (SBP)2, and (SBP)3 respectively, the concentration of the quantum dot QD-MMES is 25 mg / mL, the concentrations of the initiators SBP, (SBP)2, and (SBP)3 are all 0.5 mg / mL, and the rotation speed of the spin coating is about 2000 rpm. The mixed solution is cured into a film, and then the film layer is exposed.

[0117] As shown in Fig. 34, the exposure times are 2 s, 5 s, 10 s, 15 s, 20 s, 30 s, 45 s, and 60 s respectively, and the converted exposure amounts are 20 mJ / cm 2 , 50 mJ / cm 2 , 100 mJ / cm 2 , 150 mJ / cm 2 , 200 mJ / cm 2 , 300 mJ / cm 2 , 450 mJ / cm 2 , 600 mJ / cm 2 respectively. As shown in Fig. 34, initiators SBP and (SBP)2 achieve a 100% residual film rate at an exposure amount of 300 mJ / cm 2 , while initiator (SBP)3 already achieves a 100% residual film rate at an exposure amount of 150 mJ / cm 2 . This indicates that initiator (SBP)3 can achieve a 100% residual film rate at a lower exposure amount, showing that initiator (SBP)3 has a better cross-linking effect on quantum dots.

[0118] Fig. 35 shows scanning electron microscope photos and atomic force microscope photos of three quantum dot light-emitting layers after exposure and development. The initiators corresponding to the three quantum dot light-emitting layers are SBP, (SBP)2, and (SBP)3 respectively, and the corresponding exposure amounts are all 150 mJ / cm 2 . As can be seen from the scanning electron microscope photos and atomic force microscope photos in Fig. 35, all three quantum dot light-emitting layers have relatively good compactness and excellent film layer quality, indicating that the ligands of the quantum dots all underwent relatively good polymerization reactions, showing that initiators SBP, (SBP)2, and (SBP)3 all help to form high-quality patterned quantum dot light-emitting layers. Furthermore, comparing the three quantum dot light-emitting layers, the quantum dot light-emitting layer containing initiator (SBP)3 is the most compact and has the best film layer quality after exposure and development compared to the quantum dot light-emitting layers containing initiators SBP and (SBP)2.

[0119] Figure 36 shows the relationship between the concentration of initiator (SBP)3 and the thickness of the quantum dot emissive layer. In this experiment, (SBP)3 was selected as the initiator, and the exposure dose was 150 mJ / cm². 2 The settings are adjusted, the quantum dot concentration is set to 25 mg / mL, and the initiator (SBP) 3 concentration is changed to 0.2 mg / mL, 0.4 mg / mL, 0.6 mg / mL, 0.8 mg / mL, and 1.0 mg / mL, respectively. After exposing and developing the quantum dot emissive layer, the film thickness of the quantum dot emissive layer is measured using a step meter. As shown in Figure 36, the thickness of the quantum dot emissive layer gradually increases with increasing initiator (SBP) 3 concentration.

[0120] Figure 37 shows fluorescence microscope images of quantum dot emissive layers after processing such as film curing, exposure, and development of mixed solutions containing different concentrations of initiator (SBP) 3. As can be seen from Figure 37, quantum dot emissive layers containing different concentrations of initiator (SBP) 3 all exhibit a relatively good patterning effect.

[0121] Figure 38 shows photographs of patterned red, green, and blue quantum dot emissive layers on backplanes with different pixel densities (Pixels Per Inch, PPI). The center photograph represents the green quantum dot emissive layer, the center left photograph represents the red quantum dot emissive layer, and the center right photograph represents the blue quantum dot emissive layer. Taking the red quantum dot emissive layer as an example, the manufacturing process is generally as follows: First, a solution containing a hole transport material is spin-coated onto the backplane, then a mixed solution containing red quantum dots and initiator (SBP) 3 is spin-coated and cured into a film, followed by 15s exposure, and then development with PGMEA to obtain a patterned red quantum dot emissive layer. Patterned green and blue quantum dot emissive layers can be obtained in a similar manner. The pixel densities of the backplane can be set to 460 ppi and 500 ppi, respectively, and thus, as shown in Figure 38, six different quantum dot emissive layers can be obtained. As can be seen from Figure 38, all six quantum dot light-emitting layers exhibit relatively good patterning effects, indicating that initiator (SBP) 3 has universal applicability with different quantum dots (red, green, and blue quantum dots) and backplanes with different pixel densities (460 ppi and 500 ppi).

[0122] Figure 39 examines the effect of initiator (SBP) 3 concentration on the current efficiency of the light-emitting device, with initiator (SBP) 3 concentrations set to 0 mg / mL, 0.2 mg / mL, 0.4 mg / mL, 0.6 mg / mL, and 0.8 mg / mL, respectively. As shown in Figure 39, curve A1 represents the current efficiency curve of the light-emitting device with respect to voltage when the initiator (SBP) 3 concentration is 0 mg / mL, and as comparison curves, curves A2 to A5 represent the current efficiency curves of the light-emitting device with respect to voltage when the initiator (SBP) 3 concentrations are 0.2 mg / mL, 0.4 mg / mL, 0.6 mg / mL, and 0.8 mg / mL, respectively. As can be seen from Figure 39, even when the initiator concentration is increased to 0.8 mg / mL and the voltage is increased from 2V to 6V, the current efficiency of the light-emitting device remains almost the same as the current efficiency of comparison curve A1. This indicates that the influence of initiator (SBP) 3 on the current efficiency of the quantum dot material is very low, and therefore negligible, making it a very ideal initiator material.

[0123] Figure 40 examines the effect of initiator (SBP) 3 concentration on the external quantum efficiency of the light-emitting device, with initiator (SBP) 3 concentrations set to 0 mg / mL, 0.2 mg / mL, 0.4 mg / mL, 0.6 mg / mL, and 0.8 mg / mL, respectively. As shown in Figure 40, curve B1 represents the curve of the external quantum efficiency of the light-emitting device in response to voltage when the initiator (SBP) 3 concentration is 0 mg / mL, and as comparison curves, curves B2 to B5 represent the curves of the external quantum efficiency of the light-emitting device in response to voltage when the initiator (SBP) 3 concentrations are 0.2 mg / mL, 0.4 mg / mL, 0.6 mg / mL, and 0.8 mg / mL, respectively. As can be seen from Figure 40, even when the initiator concentration is increased to 0.8 mg / mL and the voltage is increased from 2V to 6V, the external quantum efficiency of the light-emitting device is almost the same as the external quantum efficiency of comparison curve B1. This indicates that the influence of initiator (SBP)3 on the external quantum efficiency of the quantum dot material is very low, and therefore negligible, making it a very ideal initiator material.

[0124] As can be seen from the various data and photographs above, initiators SBP, (SBP)2, and (SBP)3 all exhibit relatively good patterning effects on the quantum dot emissive layer, which helps in the production of higher quality patterned quantum dot emissive layers. Comparing initiators SBP, (SBP)2, and (SBP)3, initiator (SBP)3 exhibits the best patterning effect on the quantum dot emissive layer.

[0125] Another aspect of the present disclosure provides a quantum dot light-emitting layer. The quantum dot light-emitting layer comprises a plurality of quantum dots, wherein at least some of the quantum dots have ligands on their surfaces, the quantum dot light-emitting layer is produced by crosslinking the ligands on the quantum dot surfaces with an initiator, the ligands on the quantum dot surfaces may be ligands described in any of the above examples, and the initiator may be an initiator described in any of the above examples.

[0126] The structural formula of the initiator (1) is [ka] R11, R12, R13, R14, and R15 may be the same or different from each other, and each of R11, R12, R13, R14, and R15 may be one selected from a hydrogen atom, a group containing a nitrogen atom and a hydrogen atom, an ester group, and an alkyl group; R21, R22, R23, and R24 may be the same or different from each other, and each of R21, R22, R23, and R24 may be one selected from a hydrogen atom, a fluorine atom, a sulfur atom, an oxygen atom, an ester group, an alkyl group, and a group containing a nitrogen atom and a hydrogen atom; and R3 may be one selected from a sulfur atom, an oxygen atom, an ester group, an amide group, an alkyl group, a hydrogen atom, and a fluorine atom. R4 may be any one selected from an ester group, an alkyl group, and a group containing a nitrogen atom and a hydrogen atom, and R31, R32, R33, R34, R35, R36, R37, R38, and R39 may or may not be present and may be the same or different from each other, and if at least one of R31, R32, R33, R34, R35, R36, R37, R38, and R39 is present it may be any one selected from an ester group, an alkyl group, and a group containing a nitrogen atom and a hydrogen atom, n is a positive integer of 1 or more, and the groups of the initiator must contain at least one of a sulfur atom, an oxygen atom, and a group containing a nitrogen atom and a hydrogen atom.

[0127] The structural formula (4) of the ligand on the quantum dot surface is [ka] R5 is coordinately bonded to the quantum dot surface and is selected from a mercapto group, a carboxyl group, or an amino group; R6 is selected from an ester group or an ether group; and R7 is selected from an ester group or an ether group.

[0128] Since the initiator base contains at least one of a group containing a sulfur atom, an oxygen atom, a nitrogen atom, and a hydrogen atom, the activity and stability of radicals can be improved, whereby the initiator has high initiation activity, thereby improving the initiation rate of the initiator, improving the reactivity between the quantum dots and the initiator in the exposed area per unit time, accelerating the initiation of the polymerization reaction of the carbon-carbon double bond of the ligand on the quantum dot surface, and further helping to form a high-quality patterned quantum dot light-emitting layer.

[0129] In some embodiments, the structural formula (4) of the ligand on the quantum dot surface is specifically

Chemical formula

Chemical formula

Chemical formula

[0130] The initiator (SBP)3 has more initiation sites. Therefore, the initiation rate of the initiator (SBP)3 per unit time is faster, whereby the crosslinking effect of the quantum dots is better.

[0131] In some embodiments, the structural formula (4) of the ligand on the quantum dot surface is specifically

Chemical formula

Chemical formula

[0132] Initiator (SBP)2 also has more initiation sites, which can improve the initiator initiation rate per unit time, thereby resulting in a relatively good crosslinking effect of quantum dots.

[0133] In some embodiments, the structural formula (4) of the ligand on the quantum dot surface is specifically [ka] It is abbreviated as MMES, and the structural formula of the initiator (1) is specifically [ka] The structural formula of the quantum dot emissive layer, abbreviated as SBP, is: [ka] Here, QD represents a quantum dot, and k is a positive integer greater than or equal to 1.

[0134] Compared to initiators (SBP)2 and (SBP)3, initiator SBP is easier to synthesize and therefore readily obtainable.

[0135] In initiators SBP, (SBP)2, and (SBP)3, a pyrrole group and a sulfur atom are introduced simultaneously. Thus, on the one hand, under light irradiation, the initiator can abstract a hydrogen atom from the pyrrole group, thereby converting the pyrrole group into an active amine radical. The resulting amine radical can react with oxygen to produce a peroxide, which can then abstract another hydrogen atom, further generating other amine radicals. Oxygen does not consume the triplet state benzophenone structural unit throughout the entire process. Therefore, introducing the pyrrole group eliminates the polymerization inhibitory effect of oxygen on radical polymerization reactions in the system. Furthermore, the active amine radical has low steric hindrance and high initiation activity, accelerating the initiation of the polymerization reaction of carbon-carbon double bonds of ligands on the quantum dot surface. On the other hand, under light irradiation, the sulfur atom can cause the sulfur ether bond to break, generating sulfur radicals, benzene radicals, etc., increasing the number of radical active centers. Moreover, since the sulfur atom is a weak electron-donating group, the entire molecular structure of the initiator becomes a push-pull-push conjugated system, causing a clear redshift in the absorption of the entire molecule. Therefore, by simultaneously introducing pyrrole groups and sulfur atoms into the molecular structure, the activity and stability of radicals can be significantly improved, thereby greatly increasing the initiator's initiation rate and further increasing the reactivity between quantum dots and initiators within the exposure area per unit time, which helps in forming high-quality quantum dot patterns.

[0136] In some alternative embodiments, the structural formula of the ligand on the quantum dot surface is [ka] The initiator is a mixture of benzophenone and an amine compound, and the structural formula of the quantum dot light-emitting layer produced by crosslinking the initiator with the quantum dots is [ka] Here, R5 is selected from a mercapto group, a carboxyl group, or an amino group; R6 is selected from an ester group or an ether group; R7 is selected from an ester group or an ether group; QD represents a quantum dot; and k is a positive integer greater than or equal to 1.

[0137] In some other alternative embodiments, the structural formula of the ligand on the quantum dot surface is [ka] The initiator is a mixture of a benzophenone derivative and an amine compound, and the structural formula of the benzophenone derivative is [ka] The structural formula of the quantum dot light-emitting layer produced by crosslinking the initiator and quantum dots is [ka] R5 is selected from a mercapto group, a carboxyl group, or an amino group; R6 is selected from an ester group or an ether group; R7 is selected from an ester group or an ether group; R0 is selected from O, S, C6H5, OH, Br, Cl, or I; QD represents a quantum dot, k is a positive integer greater than or equal to 1, and m is a positive integer greater than or equal to 0.

[0138] In some embodiments, the patterned quantum dot light-emitting layer includes a plurality of first quantum dot patterns, a plurality of second quantum dot patterns, and a plurality of third quantum dot patterns, the first quantum dot patterns can be used to emit red light, the second quantum dot patterns can be used to emit green light, and the third quantum dot patterns can be used to emit blue light.

[0139] This quantum dot light-emitting layer can be applied to the field of electroluminescence and also to the field of photoluminescence.

[0140] In the field of electroluminescence, for example, a quantum dot light-emitting layer can be used as the light-emitting layer of a quantum dot light-emitting diode device. Under the action of an electric field, electrons and holes generated in the device are transported to the quantum dot light-emitting layer, where they recombine as excitons, causing an energy level transition and resulting in light emission.

[0141] In the field of photoluminescence, the quantum dot light-emitting layer may be integrated into a backlight, or it may be integrated as a color film inside a panel, and can be applied to liquid crystal display panels, organic light-emitting diode display panels, or sub-millimeter organic light-emitting diode display panels. Alternatively, the quantum dot light-emitting layer may be installed on the light-emitting side of an organic light-emitting diode display panel that emits blue light, and upon excitation with blue light, it emits red, green, and blue light, thereby realizing full-color display.

[0142] Figure 41 shows a schematic diagram of the structure of the light-emitting device 300. As shown in Figure 41, the light-emitting device 300 includes a first electrode layer 301, a hole injection layer 302 located on the first electrode layer 301, a hole transport layer 303 located on the side of the hole injection layer 302 away from the first electrode layer 301, a quantum dot light-emitting layer 304 located on the side of the hole transport layer 303 away from the first electrode layer 301, which may be a quantum dot light-emitting layer as described in any of the above embodiments, an electron transport layer 305 located on the side of the quantum dot light-emitting layer 304 away from the first electrode layer 301, and a second electrode layer 306 located on the side of the electron transport layer 305 away from the first electrode layer 301.

[0143] The light-emitting device 300 is an electroluminescent device. Its light-emitting principle is as follows: a quantum dot light-emitting layer 304 is sandwiched between a first electrode 301 and a second electrode 306. Power is supplied to the first electrode 301 and the second electrode 306, respectively. Due to the action of the electric field, electrons and holes are generated, transported to the quantum dot light-emitting layer 304, and recombine as excitons in the quantum dot light-emitting layer 304, causing an energy level transition and resulting in light emission. The light-emitting device 300 has advantages such as high color purity, high contrast, and high stability.

[0144] In some embodiments, the first electrode 301 is the anode and the second electrode 306 is the cathode, in which case the light-emitting device 300 is in a forward configuration. The material of the first electrode 301 may be ITO, and the material of the second electrode 306 may be Al.

[0145] In some alternative embodiments, the light-emitting device 300 may have an inverted structure, in which case the stacking relationship of each film layer of the light-emitting device 300 is a cathode, an electron transport layer located on the cathode, a quantum dot light-emitting layer located on the side of the electron transport layer away from the cathode, a hole transport layer located on the side of the quantum dot light-emitting layer away from the cathode, a hole injection layer located on the side of the hole transport layer away from the cathode, and an anode located on the side of the hole injection layer away from the cathode.

[0146] The light-emitting device 300 may be a top-emission type or a bottom-emission type.

[0147] Figure 42 shows four fluorescence microscope images. R represents the patterning effect of a red quantum dot emissive layer on a 460ppi backplane, G represents the patterning effect of a green quantum dot emissive layer on a 460ppi backplane, G represents the patterning effect of a blue quantum dot emissive layer on a 460ppi backplane, RGB represents the patterning effect of three quantum dot emissive layers of red, green, and blue on a 460ppi backplane, and the initiator of the quantum dot emissive layer may be SBP, or (SBP)2, or (SBP)3. As can be seen from Figure 42, both monochromatic quantum dot emissive layers and red, green, and blue overlay quantum dot emissive layers exhibit relatively good patterning effects.

[0148] Figure 43 shows three spectral diagrams. EL-RQD represents the spectral diagram of an emissive device containing a red quantum dot emissive layer under electrical excitation, EL-GQD represents the spectral diagram of an emissive device containing a green quantum dot emissive layer under electrical excitation, and EL-BQD represents the spectral diagram of an emissive device containing a blue quantum dot emissive layer under electrical excitation. As shown in Figure 43, as the voltage increases, all three spectral diagrams show only the emission peaks of monochromatic quantum dots, with no crosstalk of other colors, indicating that a full-color quantum dot overlay is realized.

[0149] Other technical effects of the light-emitting device 300 can be found by referring to the technical effects of the quantum dot light-emitting layer described in the above embodiment, and for the sake of brevity, they will not be repeated here.

[0150] Figure 44 shows a block diagram of the display device 400. The display device 400 includes a plurality of subpixels, and one light-emitting device 300 is installed in each subpixel. At least two of the multiple light-emitting devices 300 emit light of different colors. For example, some of the multiple light-emitting devices 300 include a red quantum dot light-emitting layer and are used to emit red light, some of the multiple light-emitting devices 300 include a green quantum dot light-emitting layer and are used to emit green light, and some of the multiple light-emitting devices 300 include a blue quantum dot light-emitting layer and are used to emit blue light, thereby enabling the display device 400 to achieve full-color display.

[0151] The display device 400 may be any product or component that displays based on quantum dots, such as a mobile phone, tablet PC, television, display, laptop computer, digital photo frame, or navigator.

[0152] The display device 400 can have substantially the same technical effects as the light-emitting device 300 described in the above embodiment, and therefore, for the sake of brevity, it will not be described again here.

[0153] To be understood, in this specification, terms such as first, second, third, etc., may be used to describe various elements, members, regions, layers, and / or parts, but these elements, members, regions, layers, and / or parts should not be limited by these terms. These terms are used solely to distinguish one element, member, region, layer, or part from other elements, members, regions, layers, or parts. Accordingly, the first element, member, region, layer, or part discussed above may be referred to as the second element, member, region, layer, or part without departing from the teachings of this disclosure.

[0154] In this specification, spatially relative terms such as “row,” “column,” “below,” “above,” “left,” and “right” can be used, for convenience of explanation, to describe the relationship between one element or feature shown in the drawings and other elements or features. As is to be understood, these spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. For example, if the device in the drawings is reversed, the orientation of an element described as “below another element or feature” becomes “above another element or feature.” Thus, the exemplary term “below” can encompass both the …above and …below orientations. The orientation of the device can also be in other ways (90-degree rotation or other orientations), and the spatially relative descriptors used herein should be interpreted accordingly. Also, as is to be understood, when a layer is described as “between two layers,” it may be the only layer between those two layers, or there may be one or more intermediate layers.

[0155] The terms used herein are for the purpose of describing specific embodiments and are not intended to limit the disclosure. As used herein, the singular forms “one,” “one,” and “the” also include the plural form unless the context makes it clear. For the purposes of this specification, the terms “include” and / or “contain” specify the presence of the aforementioned features, wholes, steps, operations, elements, and / or components, but do not exclude the presence of one or more other features, wholes, steps, operations, elements, components, and / or combinations thereof, or the addition of one or more other features, wholes, steps, operations, elements, components, and / or combinations thereof. As used herein, the terms “and / or” include any and any combination of one or more of the items relating to the description. In the description herein, reference terms such as “one embodiment” and “another embodiment” mean that the specific features, structures, materials, or properties described by that embodiment are included in at least one embodiment of this disclosure. In this specification, exemplary expressions for the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or properties described herein can be combined in an appropriate manner in any one or more embodiments or examples. Also, those skilled in the art can combine different embodiments or examples and features described herein without contradiction.

[0156] To ensure understanding, when an element or layer is described as "on another element or layer," "connected to another element or layer," "coupled to another element or layer," or "adjacent to another element or layer," it may be directly on another element or layer, directly connected to another element or layer, directly coupled to another element or layer, or directly adjacent to another element or layer, or an intermediate element or layer may exist. Conversely, when an element is described as "directly on another element or layer," "directly connected to another element or layer," "directly coupled to another element or layer," or "directly adjacent to another element or layer," there is no intermediate element or layer. In no case should "on..." or "directly on..." be interpreted as requiring one layer to completely cover the layer below.

[0157] This specification describes embodiments of the disclosure with reference to schematic diagrams (and intermediate structures) of ideal embodiments of the disclosure. Therefore, variations in the illustrated shape are expected, for example, as a result of manufacturing techniques and / or tolerances. Accordingly, embodiments of the disclosure should not be construed as being limited to specific shapes of the areas shown herein, but should include variations in shape due to manufacturing, etc. Accordingly, the areas shown in the drawings are essentially illustrative, and their shapes are not intended to represent the actual shapes of the areas of the devices shown in the drawings, nor are they intended to limit the scope of the disclosure.

[0158] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as those generally understood by those skilled in the art. Furthermore, terms as defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the relevant field and / or in the context of this specification, and not as idealized or overly formal unless expressly defined herein.

[0159] While the steps of the methods of this disclosure are illustrated in a specific order in the drawings, as will be understood by those skilled in the art, this does not require or imply that these steps must be performed in that specific order unless explicitly stated in the context. Furthermore, or alternatively, multiple steps may be combined into a single step, and / or one step may be broken down into multiple steps. Steps of other methods may also be inserted between steps. The inserted steps may represent improvements to the methods described herein, or they may be unrelated to such methods. Also, certain steps may not be completely completed before the next step begins.

[0160] The above description is merely a specific embodiment of the present disclosure, and the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that are readily conceivable by a person skilled in the art within the scope of the art disclosed herein should be included within the scope of protection of the present disclosure. Accordingly, the scope of protection of the present disclosure should be the same as the scope of protection of the claims.

Claims

1. It is an initiator, and its structural formula is 【Chemistry 1】 And, R11, R12, R13, R14, and R15 are either the same or different from each other, and each of R11, R12, R13, R14, and R15 is selected from a hydrogen atom, a group containing a nitrogen atom and a hydrogen atom, an ester group, and an alkyl group; R21, R22, R23, and R24 are either the same or different from each other, and each of R21, R22, R23, and R24 is selected from a hydrogen atom, a fluorine atom, a sulfur atom, an oxygen atom, an ester group, an alkyl group, and a group containing a nitrogen atom and a hydrogen atom; R3 is selected from a sulfur atom, an oxygen atom, an ester group, an amide group, an alkyl group, a hydrogen atom, and a fluorine atom; and R4 is an ester A group selected from a group, an alkyl group, and a group comprising a nitrogen atom and a hydrogen atom, wherein R31, R32, R33, R34, R35, R36, R37, R38, and R39 may or may not be present and may or may be the same as or different from each other, and if at least one of R31, R32, R33, R34, R35, R36, R37, R38, and R39 is present, it may or may not be an ester group, an alkyl group, and a group comprising a nitrogen atom and a hydrogen atom, where n is a positive integer of 1 or more, and the initiator group comprises at least one of the sulfur atom, the oxygen atom, and the group comprising a nitrogen atom and a hydrogen atom, and the initiator group refers to an initiator other than the benzophenone skeleton.

2. The initiator according to claim 1, wherein R31, R32, R33, R34, R35, R36, R37, R38, and R39 are none, R11, R12, R13, R14, and R15 are each selected from a hydrogen atom or a group containing a nitrogen atom and a hydrogen atom, R21, R22, R23, and R24 are each selected from a hydrogen atom or a fluorine atom, and R3 is one selected from a sulfur atom, an oxygen atom, an ester group, an amide group, and an alkyl group.

3. The initiator according to claim 1, wherein the group containing the nitrogen atom and the hydrogen atom is a pyrrole group or a tertiary amine group.

4. The structural formula of the initiator is 【Chemistry 2】 The initiator according to claim 1.

5. n=3, the structural formula of the initiator is 【Transformation 3】 is, or, n=2, the structural formula of the initiator is 【Chemistry 4】 is, or, n=4, the structural formula of the initiator is 【Transformation 5】 is, or, n=1, the structural formula of the initiator is 【Transformation 6】 The initiator according to claim 4.

6. The structural formula of the initiator is 【Transformation 7】 The initiator according to claim 1, wherein x and y are both positive integers of 1 or more.

7. The initiator according to claim 6, wherein the number of carbon atoms in the branched chain bonded to the nitrogen atom is 2 to 30.

8. An initiator which is a mixture of benzophenone and an amine compound, or a mixture of a benzophenone derivative and an amine compound, The structural formula of the aforementioned benzophenone derivative is 【Transformation 8】 And R0 is O, S, C ６ H ５ An initiator that is one of the following selected from OH, Br, Cl, and I, where m is a positive integer greater than or equal to 0.

9. The initiator according to claim 8, wherein the amine compound is pyrrole or a tertiary amine.

10. A quantum dot having a ligand on its surface, wherein the structural formula of the ligand is 【Chemistry 9】 A quantum dot wherein R5 is coordinately bonded to the surface of the quantum dot and is selected from a mercapto group, a carboxyl group, or an amino group, R6 is selected from an ester group or an ether group, and R7 is selected from an ester group or an ether group, and the ligand is configured to photosensitize with the initiator described in any one of claims 1 to 7 or any one of claims 8 to 9 under light irradiation.

11. The structural formula of the ligand is 【Chemistry 10】 The quantum dot according to claim 10.

12. A quantum dot light-emitting layer comprising a plurality of quantum dots, wherein at least some of the plurality of quantum dots have ligands on their surfaces, and the quantum dot light-emitting layer is produced by crosslinking the ligand-containing quantum dots with an initiator according to any one of claims 1 to 7 or any one of claims 8 to 9.

13. The structural formula of the ligand is 【Chemistry 11】 The structural formula of the initiator is 【Chemistry 12】 The structural formula of the quantum dot light-emitting layer is 【Chemistry 13】 is, or, The structural formula of the ligand is 【Chemistry 14】 The structural formula of the initiator is 【Chemistry 15】 The structural formula of the quantum dot light-emitting layer is 【Chemistry 16】 is, or, The structural formula of the ligand is 【Chemistry 17】 The structural formula of the initiator is [Chemistry 18] The structural formula of the quantum dot light-emitting layer is 【Chemistry 19】 And, The quantum dot light-emitting layer according to claim 12, wherein QD represents a quantum dot and k is a positive integer of 1 or more.

14. The structural formula of the ligand is 【Chemistry 20】 The initiator is a mixture of benzophenone and an amine compound, and the structural formula of the quantum dot light-emitting layer is 【Chemistry 21】 is, or, The structural formula of the ligand is 【Chemistry 22】 The initiator is a mixture of a benzophenone derivative and an amine compound, and the structural formula of the benzophenone derivative is 【Chemistry 23】 The structural formula of the quantum dot light-emitting layer is 【Chemistry 24】 And, R5 is selected from one of the following: a mercapto group, a carboxyl group, or an amino group; R6 is selected from an ester group or an ether group; R7 is selected from an ester group or an ether group; and R0 is O, S, or C. ６ H ５ The quantum dot light-emitting layer according to claim 12, wherein QD is one of OH, Br, Cl, and I, k is a positive integer greater than or equal to 1, and m is a positive integer greater than or equal to 0.

15. The quantum dot light-emitting layer according to any one of claims 12 to 14, wherein the quantum dot light-emitting layer comprises a plurality of first quantum dot patterns, a plurality of second quantum dot patterns, and a plurality of third quantum dot patterns, wherein the first quantum dot patterns are configured to emit red light, the second quantum dot patterns are configured to emit green light, and the third quantum dot patterns are configured to emit blue light.

16. A light-emitting device, The first electrode layer and A hole injection layer located on the first electrode layer, A hole transport layer located on the side of the hole injection layer away from the first electrode layer, A quantum dot light-emitting layer according to any one of claims 12 to 15, located on the side of the hole transport layer away from the first electrode layer, An electron transport layer located on the side of the quantum dot light-emitting layer away from the first electrode layer, A light-emitting device including a second electrode layer located on the side of the electron transport layer away from the first electrode layer.

17. A display device comprising a plurality of light-emitting devices according to claim 16, wherein at least two of the plurality of light-emitting devices are configured to emit light of different colors.

18. A method for manufacturing a patterned quantum dot light-emitting layer, The steps include providing a substrate and A step of coating a mixed solution onto the substrate, wherein the mixed solution comprises quantum dots and an initiator, the surface of the quantum dots has a ligand containing a carbon-carbon double bond, and the initiator is the initiator according to any one of claims 1 to 7 or any one of claims 8 to 9, A method for producing a patterned quantum dot light-emitting layer, comprising the step of initiating a polymerization reaction of the carbon-carbon double bond of the ligand under light irradiation to form a patterned quantum dot light-emitting layer.

19. The process further includes the step of curing the mixed solution applied to the substrate to form an intermediate film layer, The step of initiating a polymerization reaction of the carbon-carbon double bond of the ligand under light irradiation to form a patterned quantum dot light-emitting layer is as follows: The process involves using a mask plate to expose the intermediate film layer, passing ultraviolet light through the mask plate to expose the intermediate film layer, and under ultraviolet light irradiation, the initiator initiates the polymerization reaction of the carbon-carbon double bond of the ligand. The method according to claim 18, comprising the steps of developing the intermediate film layer after the polymerization reaction using a developer, dissolving the unexposed portion of the intermediate film layer with the developer to form the patterned quantum dot light-emitting layer.

20. The method according to claim 18 or 19, wherein the concentration of the quantum dots in the mixed solution is approximately 25 to 30 mg / mL, and the concentration of the initiator in the mixed solution is approximately 0.1 to 1.0 mg / mL.

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