Quantum dot composition, light emitting element including quantum dot composition, and display device

Abstract

A quantum dot composition, a light-emitting element comprising the quantum dot composition, and a display device are provided. The quantum dot composition includes quantum dots and ligands bound to the surface of the quantum dots, wherein the ligands include a head bound to the surface of the quantum dots and a tail containing crosslinkable functional groups. The quantum dot composition according to one or more embodiments can be applied to the emitting layer of a light-emitting element and a display device to improve the luminous efficiency and lifespan of the light-emitting element and the display device.

Description

[0001] This application claims priority and benefit to Korean Patent Application No. 10-2020-0066724, filed on June 2, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0002] One or more aspects of embodiments of this disclosure relate herein to quantum dot compositions, light-emitting elements including an emitting layer formed of a quantum dot composition, and display devices including the same. Background Technology

[0003] Various display devices are being developed for multimedia devices such as televisions, mobile phones, tablet computers, navigation systems, and / or game consoles. These display devices utilize self-emissive display elements, which display images by causing luminescent materials containing organic compounds to emit light.

[0004] In addition, efforts are underway to develop light-emitting elements that use quantum dots as light-emitting materials to enhance the color reproduction of display devices, and there is a demand (or expectation) for increasing the luminous efficiency and lifespan of light-emitting elements using quantum dots. Summary of the Invention

[0005] One or more aspects of embodiments of this disclosure relate to a quantum dot composition that can be used in the emitting layer of a light-emitting element to exhibit improved luminous efficiency.

[0006] One or more aspects of embodiments of this disclosure also relate to a light-emitting element that has improved luminous efficiency by including quantum dots in an emitting layer, the quantum dots having ligand materials with improved charge injection properties bound to their surface.

[0007] One or more aspects of embodiments of this disclosure also provide a display device that exhibits improved luminous efficiency by including a light-emitting element comprising quantum dots in an emitting layer having ligand materials with improved charge injection properties bound to its surface.

[0008] Embodiments of this disclosure provide a quantum dot composition comprising a quantum dot and a ligand bound to the surface of the quantum dot, wherein the ligand comprises: a head bound to the surface of the quantum dot; and a tail containing crosslinkable functional groups at the end of the ligand.

[0009] Crosslinkable functional groups can be thermocrosslinkable functional groups.

[0010] The ligand may also include a chain that connects the head and tail.

[0011] The chain portion can include 2 to 20 carbon atoms.

[0012] The crosslinkable functional group can be vinyl, hydroxy, carboxyl, epoxy, amide, amino, azide, oxetyl, and / or isocyanate.

[0013] The ligand can be a monodentate ligand or a bidentate ligand.

[0014] The head may include a thiol group, a dithioic acid group, a phosphonic group, a catechol group, an amino group, and / or a carboxylic acid group.

[0015] The chain may also include amino, oxygen, thio, ester, ether, aryl and / or amide groups.

[0016] The ligand can be represented by formula A or formula B.

[0017] Formula A

[0018] *-XY

[0019] Formula B

[0020]

[0021] In Equations A and B, X, X1, and X2 can each be independently S or NH, and Y can be represented by at least one of Equations 1 to 7.

[0022] "*-" indicates the location connected to the quantum dot.

[0023] Formula 1

[0024]

[0025] Formula 2

[0026]

[0027] Formula 3

[0028]

[0029] Formula 4

[0030]

[0031] Formula 5

[0032]

[0033] Formula 6

[0034]

[0035] Formula 7

[0036]

[0037] In equations 1 to 7, Indicates the position attached to formula A or formula B, and R1 and R2 are both independently alkyl groups having 1 to 20 carbon atoms, wherein the total number of carbon atoms in R1 and R2 is 20 or less.

[0038] The quantum dot composition may also include an organic solvent, and the quantum dots may be dispersed in the organic solvent.

[0039] Quantum dots can be semiconductor nanocrystals consisting of a core and a shell surrounding the core.

[0040] In one or more embodiments of this disclosure, the light-emitting element includes a first electrode, a second electrode facing the first electrode, and an emitting layer disposed between the first electrode and the second electrode. The emitting layer includes a plurality of quantum dot complexes having ligands, wherein one of the plurality of quantum dot complexes is bound to at least two other quantum dot complexes by ligands.

[0041] Quantum dot complexes may include quantum dots having a core and a shell around the core, as well as ligands having hydrophilic groups on the surface of the quantum dots.

[0042] The hydrophilic group can be a thiol group, a dithioic acid group, a phosphono group, a catechol group, an amino group, and / or a carboxylic acid group.

[0043] Ligands can include 2 to 20 carbon atoms.

[0044] In one or more embodiments of this disclosure, the display device includes: a plurality of light-emitting elements; and a light conversion layer disposed on the plurality of light-emitting elements and having a light control unit, the light control unit comprising a plurality of quantum dots interconnected by binding of ligands, wherein each of the plurality of light-emitting elements includes a first electrode, a second electrode facing the first electrode, and an emission layer disposed between the first electrode and the second electrode.

[0045] Multiple light-emitting elements can emit light of a first color, and the light control unit can include a first light control unit that transmits the first color light, a second light control unit that converts the first color light into a second color light, and a third light control unit that converts the first color light into a third color light.

[0046] Each of the multiple quantum dots may include a core and a shell surrounding the core, and the ligands in the ligands may include hydrophilic groups on the surface of the corresponding quantum dot that are bound to the multiple quantum dots.

[0047] The hydrophilic group can be a thiol group, a dithioic acid group, a phosphono group, a catechol group, an amino group, and / or a carboxylic acid group.

[0048] The display device may also include a color filter layer disposed on a plurality of light-emitting elements, wherein the color filter layer may include a first filter that transmits a first color light, a second filter that transmits a second color light, and a third filter that transmits a third color light. Attached Figure Description

[0049] The accompanying drawings are included to provide a further understanding of this disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the disclosure. In the drawings:

[0050] Figure 1 This is a combined perspective view of an electronic device of one or more embodiments;

[0051] Figure 2 An exploded perspective view of an electronic device of one or more embodiments;

[0052] Figure 3 A cross-sectional view of a display device of one or more embodiments;

[0053] Figure 4 A cross-sectional view of a light-emitting element of one or more embodiments;

[0054] Figure 5 This is a flowchart illustrating a method for manufacturing a light-emitting element according to one or more embodiments;

[0055] Figure 6 It is a schematic cross-sectional view illustrating the action of forming an emitting layer in a method for manufacturing a light-emitting element according to one or more embodiments;

[0056] Figure 7 To show in more detail Figure 6 A cross-sectional view of a portion of the quantum dot composition provided in the image;

[0057] Figure 8 A schematic diagram of a quantum dot coordination compound of one or more embodiments;

[0058] Figure 9 This is a schematic diagram illustrating a portion of a method for manufacturing a light-emitting element according to one or more embodiments;

[0059] Figure 10 This is a cross-sectional view showing the emission layer according to one or more embodiments;

[0060] Figure 11 This is a schematic view illustrating a quantum dot composition according to one or more embodiments;

[0061] Figure 12This is a view illustrating the reactions between ligands in a quantum dot composition according to one or more embodiments;

[0062] Figure 13 It is a plan view of a display device according to one or more embodiments;

[0063] Figure 14 It corresponds to Figure 13 A cross-sectional view of the display device with line II-II';

[0064] Figure 15 It is a cross-sectional view of a display device according to one or more embodiments; and

[0065] Figure 16 It is a graph showing the analysis results of the example and the comparison example. Detailed Implementation

[0066] This disclosure can be modified in many alternative forms, and therefore specific embodiments will be illustrated and described in more detail in the accompanying drawings. However, it should be understood that this disclosure is not intended to be limited to the specific forms disclosed, but rather to cover all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0067] In this description, when an element (or region, layer, portion, etc.) is referred to as being "on" another element, "connected to" or "bonded to" another element, it means that the element may be directly disposed on / directly connected to / directly bonded to the other element, or a third element may be disposed therebetween.

[0068] In this disclosure, "directly disposed" or "directly on" means that no layer, membrane, region, and / or plate is added between another element. For example, "directly disposed" can mean that two layers or two components are disposed without any additional components (such as adhesive components) between them.

[0069] The same reference numerals refer to the same elements. Additionally, in order to effectively depict the technical content, the thickness, scale, and dimensions of the elements are exaggerated in the accompanying drawings.

[0070] The term "and / or" includes all combinations of one or more of its associated constructions. When expressions such as "at least one of," "one of," and "selected from" follow a list of elements, they modify the entire list of elements (features) without modifying the individual elements (features) in the list. Furthermore, when describing embodiments of this disclosure, the term "may" refers to "one or more embodiments of this disclosure."

[0071] It will be understood that although the terms “first,” “second,” etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of exemplary embodiments of this disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. Unless the context clearly indicates otherwise, singular terms may include plural forms.

[0072] Furthermore, terms such as "below," "under," "above," and "on" are used to describe the relationships between the structures shown in the accompanying drawings. These terms are used as relative concepts and are described with reference to the directions indicated in the drawings.

[0073] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will also be understood that terms defined in common dictionaries shall be interpreted as having a meaning consistent with their meaning in the context of the relevant field, and they shall not be interpreted in an idealized or overly formalized sense, unless expressly specified herein.

[0074] It should be understood that, in this disclosure, the terms “comprising” or “having” are intended to indicate the presence of the stated features, wholes, steps, operations, elements, components or combinations thereof, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components or combinations thereof.

[0075] As used herein, the term “use” and its variants may be considered synonymous with the term “utilize” and its variants, respectively.

[0076] Furthermore, the terms “basically,” “about,” and similar terms are used as approximate terms rather than terms of degree, and are intended to describe the inherent biases in measurements or calculations that would be recognized by a person skilled in the art.

[0077] Furthermore, any numerical range described herein is intended to include all subranges with the same numerical precision contained within the described range. For example, the range “1.0 to 10.0” is intended to include all subranges between the described minimum value 1.0 and the described maximum value 10.0 (and including both the described minimum value 1.0 and the described maximum value 10.0), i.e., a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0 (such as 2.4 to 7.6). Any maximum numerical limit described herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit described in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification (including the claims) to expressly describe any subranges contained within the range expressly described herein.

[0078] In the following description, quantum dot compositions, light-emitting elements, and display devices including the same, according to one or more embodiments of the present disclosure, will be described with reference to the accompanying drawings.

[0079] Figure 1 This is a perspective view of an electronic device EA of one or more embodiments. Figure 2 This is an exploded perspective view of an electronic device EA of one or more embodiments. Figure 3 This is a cross-sectional view of a display device DD of one or more embodiments. Figure 4 This is a cross-sectional view of a light-emitting element (ED) of one or more embodiments.

[0080] In one or more embodiments, the electronic device EA can be a large electronic device (such as a television, monitor, and / or outdoor billboard). In one or more embodiments, the electronic device EA can be a small and / or medium-sized electronic device (such as a personal computer, laptop computer, personal digital terminal, car navigation unit, game console, smartphone, tablet computer, and / or camera). However, these are presented by way of example only, and the electronic device EA can be any other suitable electronic device without departing from this disclosure. Figure 1 In this embodiment, a smartphone is exemplarily shown as an electronic device EA.

[0081] An electronic device EA can display an image IM on its front surface FS. The image IM can include still images as well as moving images. Figure 1 The diagram shows the front surface FS parallel to a plane defined by a first direction DR1 and a second direction DR2 intersecting the first direction DR1. However, this is presented as an example, and in one or more other embodiments, the front surface FS of the electronic device EA may have a curved shape.

[0082] In the normal direction of the front surface FS of the electronic device EA (i.e., the thickness direction of the electronic device EA), the image IM is indicated by the third direction DR3 along its display direction. The front (or upper) surface and rear (or lower) surface of each component can be separated along the third direction DR3.

[0083] Fourth direction DR4 (see) Figure 13 The fourth direction DR4 can be the direction between the first direction DR1 and the second direction DR2. The fourth direction DR4 can lie on a plane parallel to the plane defined by the first direction DR1 and the second direction DR2. However, the directions indicated by the first direction DR1, the second direction DR2, the third direction DR3, and the fourth direction DR4 are relative concepts and can therefore be changed to other directions.

[0084] In one or more embodiments, the electronic device EA may include a foldable display device having a folding region and a non-folding region and / or a curved display device having at least one curved portion.

[0085] An electronic device EA may include a display device DD and a housing HAU. In the electronic device EA, the front surface FS may correspond to the front surface of the display device DD and may also correspond to the front surface of the window WP. Therefore, the same reference numeral FS is given (used) for the front surface of the electronic device EA, the front surface of the display device DD, and the front surface of the window WP.

[0086] The housing HAU can accommodate the display device DD. The housing HAU can be configured to cover the display device DD such that the upper surface of the display surface IS of the display device DD is exposed. The housing HAU can cover the side and bottom surfaces of the display device DD and expose all (e.g., the entire) upper surface. However, embodiments of this disclosure are not limited thereto, and the housing HAU can cover a portion of the upper surface of the display device DD as well as the side and bottom surfaces.

[0087] In one or more embodiments of the electronic device EA, the window WP may include an optically transparent insulating material. The window WP may include a transmissive region TA and a border region BZA. The front surface FS of the window WP, including the transmissive region TA and the border region BZA, corresponds to the front surface FS of the electronic device EA.

[0088] exist Figure 1 and Figure 2 In the illustration, the transmission region TA is shown in a rectangular shape with circular vertices. However, this is shown exemplarily, and the transmission region TA can have various suitable shapes and is not limited to any one embodiment.

[0089] The transmissive region TA can be an optically transparent region. The border region BZA can be a region with a relatively lower transmittance than the transmissive region TA. The border region BZA can have a predetermined (or set) color. The border region BZA can be adjacent to the transmissive region TA and can surround the transmissive region TA. The border region BZA can define the shape of the transmissive region TA. However, the embodiments of this disclosure are not limited to the embodiments shown, and the border region BZA can be provided only adjacent to one side of the transmissive region TA, and a portion of the border region BZA can be omitted.

[0090] The display device DD can be positioned below the window WP. In this description, "below" can indicate a direction or side opposite to the direction or side of the display device DD along which it provides the image.

[0091] In one or more embodiments, the display device DD may be substantially configured to generate an image IM. The image IM generated in the display device DD is displayed on a display surface IS and viewed by a user from the outside through a transmissive region TA. The display device DD includes a display area DA and a non-display area NDA. The display area DA may be an area activated according to an electrical signal. The non-display area NDA may be an area covered by a border area BZA. The non-display area NDA is adjacent to the display area DA. The non-display area NDA may surround the display area DA.

[0092] Reference Figure 3 The display device DD may include a display panel DP and a light control layer PP disposed on the display panel DP. The display panel DP may include a display element layer DP-EL. The display element layer DP-EL includes a light-emitting element ED (see...). Figure 4 ).

[0093] A light control layer (PP) can be disposed on the display panel (DP) to control the light reflected from the display panel (DP) due to external light. The light control layer (PP) may include, for example, a polarizing layer and / or a color filter layer.

[0094] In one or more embodiments of the display device DD, the display panel DP can be a light-emitting display panel. For example, the display panel DP can be a quantum dot light-emitting display panel including quantum dot light-emitting elements. However, the embodiments of this disclosure are not limited thereto.

[0095] The display panel DP may include a substrate BS, a circuit layer DP-CL disposed on the substrate BS, and a display element layer DP-EL disposed on the circuit layer DP-CL.

[0096] The substrate BS can be a component providing a substrate surface on which the display element layer DP-EL is disposed. The substrate BS can be a glass substrate, a metal substrate, a plastic substrate, etc. However, the embodiments of this disclosure are not limited thereto, and the substrate BS can be an inorganic layer, an organic layer, or a composite material layer (including inorganic and organic materials). The substrate BS can be a flexible substrate that can be easily bent and / or folded.

[0097] In one or more embodiments, the circuit layer DP-CL may be disposed on the substrate BS, and the circuit layer DP-CL may include multiple transistors. Each transistor may include a control electrode, an input electrode, and an output electrode. For example, the circuit layer DP-CL may include a switching transistor and a driving transistor to drive the light-emitting element ED of the display element layer DP-EL.

[0098] Figure 4 This is a view showing a light-emitting element ED according to one or more embodiments, with reference to Figure 4 According to one or more embodiments, a light-emitting element ED includes a first electrode EL1, a second electrode EL2 facing the first electrode EL1, and a plurality of functional layers disposed between the first electrode EL1 and the second electrode EL2 and having an emission layer EML.

[0099] Multiple functional layers may include a hole transport region (HTR) disposed between the first electrode EL1 and the emitter layer (EML) and an electron transport region (ETR) disposed between the emitter layer (EML) and the second electrode EL2. In one or more embodiments, a capping layer may be further disposed on the second electrode EL2.

[0100] Both the hole transport region (HTR) and the electron transport region (ETR) can include multiple sub-functional layers. For example, the hole transport region (HTR) can include a hole injection layer (HIL) and a hole transport layer (HTL) as sub-functional layers, and the electron transport region (ETR) can include an electron injection layer (EIL) and an electron transport layer (ETL) as sub-functional layers. However, embodiments of this disclosure are not limited thereto, and the hole transport region (HTR) can also include an electron blocking layer as a sub-functional layer, and the electron transport region (ETR) can also include a hole blocking layer as a sub-functional layer.

[0101] In a light-emitting element (ED) according to one or more embodiments, a first electrode EL1 is conductive. The first electrode EL1 may be formed of a metal alloy or any suitable conductive compound. The first electrode EL1 may be an anode. The first electrode EL1 may be a pixel electrode.

[0102] In a light-emitting element (ED) according to one or more embodiments, the first electrode EL1 may be a reflective electrode. However, embodiments of this disclosure are not limited thereto. For example, the first electrode EL1 may be a transmissive electrode or a transmissive-reflective electrode. When the first electrode EL1 is a transmissive-reflective electrode or a reflective electrode, the first electrode EL1 may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, compounds thereof, or mixtures thereof (e.g., a mixture of Ag and Mg). In one or more embodiments, the first electrode EL1 may have a multilayer structure including a reflective or transmissive-reflective film formed from any of the materials described above and a transparent conductive film formed from indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc. For example, the first electrode EL1 may be a multilayer metal film and may have a stacked structure of ITO / Ag / ITO metal films.

[0103] A hole transport region (HTR) can be disposed on the first electrode EL1. The hole transport region (HTR) may include a hole injection layer (HIL), a hole transport layer (HTL), etc. In one or more embodiments, in addition to the hole injection layer (HIL) and the hole transport layer (HTL), the hole transport region (HTR) may also include at least one of a hole buffer layer and an electron blocking layer. The hole buffer layer can compensate for the resonant distance according to the wavelength of light emitted from the emitter layer (EML), and thus can increase the luminous efficiency. Materials that can be included in the hole transport region (HTR) can be used as materials included in the hole buffer layer. The electron blocking layer is a layer used to prevent or reduce the injection of electrons from the electron transport region (ETR) into the hole transport region (HTR).

[0104] The hole transport region HTR can have a single layer formed of a single material (e.g., composed of a single material), a single layer formed of multiple different materials, or a multilayer structure comprising multiple layers formed of multiple different materials. For example, the hole transport region HTR can have a single-layer structure formed of multiple different materials, or a structure in which hole injection layer HIL / hole transport layer HTL, hole injection layer HIL / hole transport layer HTL / hole buffer layer, hole injection layer HIL / hole buffer layer, hole transport layer HTL / hole buffer layer, or hole injection layer HIL / hole transport layer HTL / electron blocking layer are stacked from the first electrode EL1 in the stated order, but the embodiments are not limited thereto.

[0105] Hole transport regions (HTRs) can be formed using one or more suitable methods, such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) methods, inkjet printing, laser printing, and / or laser-induced thermal imaging (LITI) methods.

[0106] Hole injection layer HIL can include, for example, phthalocyanine compounds (such as copper phthalocyanine), N,N'-diphenyl-N,N'-bis[4-(di(m-tolyl)-amino)-phenyl]-biphenyl-4,4'-diamine (DNTPD), 4,4',4”-[tris(3-methylphenyl)phenylamino]triphenylamine (m-MTDATA), 4,4',4”-tris(N,N-diphenylamino)triphenylamine (TDATA), 4,4',4”-tris[N-(2-naphthyl)-N-phenylamino]triphenylamine (2-TNATA), poly(3,4-ethylenedioxythiophene) / poly(4-styrene) Poly(phenylene sulfonate) (PEDOT / PSS), polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), polyaniline / camphor sulfonic acid (PANI / CSA), polyaniline / poly(4-styrene sulfonate) (PANI / PSS), N,N'-di(naphthyl-1-yl)-N,N'-diphenyl-benzidine (NPB), triphenylamine-containing polyether ketone (TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium tetra(pentafluorophenyl)borate, dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexaonitrile (HAT-CN), etc.

[0107] Hole transport layers (HTLs) may include, for example, carbazole derivatives (such as N-phenylcarbazole and / or polyvinylcarbazole), fluorene derivatives, N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD), triphenylamine derivatives (such as 4,4',4”-tris(N-carbazolyl)triphenylamine (TCTA)), N,N'-bis(naphthyl-1-yl)-N,N'-diphenyl-benzidine (NPB), 4,4'-cyclohexylene-bis[N,N-bis(4-methylphenyl)aniline] (TAPC), 4,4'-bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl (HMTPD), 1,3-bis(N-carbazolyl)benzene (mCP), etc.

[0108] The emitter layer (EML) can be disposed on the hole transport region (HTR). In a light-emitting element (ED) according to one or more embodiments, the emitter layer (EML) can be formed from a quantum dot composition of one or more embodiments. The emitter layer (EML) includes a plurality of quantum dot complexes (QD-C). The quantum dot complexes (QD-C) included in the emitter layer (EML) can be in a state of being bound to two or more other quantum dot complexes (QD-C). (Refer to...) Figure 7 and Figure 8 A more detailed description of the quantum dot complex QD-C.

[0109] In one or more embodiments of the light-emitting element (ED), the emission layer EML may include a host material and a dopant. In one or more embodiments, the emission layer EML may include a quantum dot complex (QD-C) as a dopant material. In one or more embodiments, the emission layer EML may also include a host material. In one or more embodiments of the light-emitting element (ED), the emission layer EML can emit fluorescence. For example, the quantum dot complex (QD-C) can be used as a fluorescent dopant material.

[0110] The emitter layer (EML) can, for example, have a thickness of about 5 nm to about 20 nm or about 10 nm to about 20 nm.

[0111] The emitter layer EML can be formed using one or more suitable methods (such as vacuum deposition, spin coating, casting, Langmuir-Blodget (LB) method, inkjet printing, laser printing, laser-induced thermal imaging (LITI) method, etc.).

[0112] In one or more embodiments of the light-emitting element (ED), the electron transport region (ETR) may be disposed on the emitter layer (EML). The electron transport region (ETR) may include at least one of a hole blocking layer, an electron transport layer (ETL), and an electron injection layer (EIL), but the embodiments of this disclosure are not limited thereto.

[0113] The electron transport region (ETR) can have a single layer formed of a single material (e.g., composed of a single material), a single layer formed of multiple different materials, or a multilayer structure comprising multiple layers formed of multiple different materials.

[0114] For example, the electron transport region (ETR) may have a single-layer structure of an electron injection layer (EIL) or an electron transport layer (ETL), or it may have a single-layer structure formed of an electron injection material and an electron transport material. In one or more embodiments, the ETR may have a single-layer structure formed of a variety of different materials, or it may have a structure in which the electron transport layer (ETL) / electron injection layer (EIL) and the hole blocking layer (ETL) / electron transport layer (ETL) / electron injection layer (EIL) are stacked from the emitter layer (EML) in the stated order, but is not limited thereto. The thickness of the ETR may be, for example, from approximately to approximately

[0115] The electron transport region (ETR) can be formed using one or more suitable methods, such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) method, inkjet printing, laser printing, laser-induced thermal imaging (LITI) method, etc.

[0116] When the electron transport region (ETR) includes an electron transport layer (ETL), the ETL may include anthracene compounds. However, embodiments of this disclosure are not limited thereto, and the ETL may include, for example, tris(8-hydroxyquinoline)aluminum (Alq3), 1,3,5-tris[(3-pyridyl)-benzyl-3-yl]benzene, 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzimidazol-1-yl)phenyl)-9,10-dinaphthylanthracene, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1, 10-Phenanthroline (Bphen), 3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(naphthyl-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD), bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum (BAlq), bis(benzoquinoline-10-hydroxy)beryllium (Bebq2), 9,10-bis(naphthyl-2-yl)anthracene (ADN), or mixtures thereof. The thickness of the electron transport layer (ETL) can range from approximately to approximately And it can be, for example, from about to approximately When the thickness of the electron transport layer (ETL) meets the range described above, satisfactory (or suitable) electron transport properties can be obtained without significantly increasing the driving voltage.

[0117] When the electron transport region (ETR) includes an electron injection layer (EIL), the ETR may include a metal halide, a lanthanide, or a co-deposited material of a metal halide and a lanthanide. The metal halide may be an alkali metal halide. For example, the ETR may include LiF, lithium hydroxyquinoline (Liq), Li₂O, BaO, NaCl, CsF, Yb, RbCl, RbI, KI, and / or KI:Yb, but the embodiments of this disclosure are not limited thereto. The EIL may also be formed from a mixture of an electron injection material and an insulating organometallic salt. The organometallic salt may be selected from, for example, metal acetates, metal benzoates, metal acetoacetates, metal acetylacetonates, and metal stearates. The thickness of the EIL may be from approximately... to approximately and from the agreement to approximately When the thickness of the electron injection layer (EIL) meets the range described above, satisfactory (or suitable) electron injection properties can be obtained without significantly increasing the driving voltage.

[0118] The electron transport region (ETR) may include a hole blocking layer as described above. The hole blocking layer may include, but is not limited to, at least one of, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and 4,7-diphenyl-1,10-phenanthroline (Bphen).

[0119] The second electrode EL2 can be disposed on the electron transport region ETR. The second electrode EL2 can be a common electrode or a cathode. The second electrode EL2 can be a transmission electrode, a transmission-reflection electrode, or a reflection electrode. When the second electrode EL2 is a transmission electrode, the second electrode EL2 can be formed of a transparent metal oxide (e.g., indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc.).

[0120] When the second electrode EL2 is a transmissive or reflective electrode, the second electrode EL2 may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, Yb, their compounds (e.g., AgYb, AgMg and / or MgAg compounds, etc., depending on their content) or mixtures thereof (e.g., mixtures of Ag and Mg, mixtures of Ag and Yb, etc.). In one or more embodiments, the second electrode EL2 may have a multilayer structure, which includes a reflective or transmissive film formed from any of the materials described above and a transparent conductive film formed from indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc.

[0121] In one or more embodiments, the second electrode EL2 may be connected to an auxiliary electrode. When the second electrode EL2 is connected to the auxiliary electrode, the resistance of the second electrode EL2 may be reduced.

[0122] Figure 5 This is a flowchart illustrating a method for manufacturing a light-emitting element according to one or more embodiments. Figure 6 The action of providing a pre-emitting layer (S100) in a method for manufacturing a light-emitting element according to one or more embodiments is illustrated schematically. Figure 7 Showing more details Figure 6 A portion (region “AA”) of the quantum dot composition QCP provided in the present invention. Figure 8 The quantum dot QD and the ligand LD bound to the surface of the quantum dot QD are schematically shown.

[0123] A method for manufacturing a light-emitting element according to one or more embodiments may include providing a pre-emitting layer (S100) and providing heat to form the emitting layer (S200).

[0124] The provision of a pre-emission layer (S100) can be performed by providing a quantum dot composition QCP on the hole transport region HTR. The quantum dot composition QCP can be provided between portions of the pixel-defined film PDL via a nozzle NZ. Although in Figure 6 In this embodiment, the hole transport region HTR is shown as a common layer stacked with the pixel defining film PDL; however, embodiments of this disclosure are not limited thereto, and the hole transport region HTR may be disposed between the pixel defining films PDL. For example, the hole transport region HTR may be provided between the pixel defining films PDL using an inkjet printing method.

[0125] Reference Figure 7 One or more embodiments of the quantum dot composition QCP may include a quantum dot QD and a ligand LD bound to the surface of the quantum dot QD. The quantum dot QD may have the ligand LD bound to its surface to form a quantum dot complex QD-C. The quantum dot complex QD-C has the ligand LD bound to the surface of the quantum dot QD, and thus can retain charge injection properties and has improved dispersibility and end-capping properties.

[0126] In one or more embodiments, the quantum dot composition QCP may also include an organic solvent SV. For example, the organic solvent SV may include hexane, toluene, chloroform, dimethyl sulfoxide, and / or dimethylformamide. However, the embodiments of this disclosure are not limited thereto.

[0127] Quantum dots (QDs) can be dispersed in an organic solvent (SV) and provided to form an emission layer. The dispersibility of the quantum dots (QDs) in the organic solvent (SV) may increase when ligands (LDs) bind to the surface of the quantum dots (QDs). In methods for forming the emission layer, evaporation of the organic solvent (SV) may be further included after providing the quantum dot composition (QCP).

[0128] Reference Figure 8 Quantum dots (QDs) may include a core (CR) and a shell (SL) surrounding the core (or around the core). However, embodiments of this disclosure are not limited thereto, and quantum dots (QDs) may have a monolayer structure containing only the core (CR). The shell SL of a quantum dot (QD) with a core / shell structure may serve as a protective layer to prevent or reduce chemical deformation of the core (CR) to maintain its semiconductor properties and / or as a charging layer to impart electrophoretic properties to the quantum dot (QD). The shell SL may be a single layer or multiple layers. The interface between the core (CR) and the shell SL may have a concentration gradient in which the concentration of elements present in the shell SL decreases towards the center.

[0129] Quantum dots (QDs) in one or more embodiments may be semiconductor nanocrystals selected from group II-VI compounds, group III-V compounds, group III-VI compounds, group IV-VI compounds, group IV elements, group IV compounds, and combinations thereof (multiple combinations thereof).

[0130] Group II-VI compounds can be selected from the group consisting of binary, ternary, and quaternary compounds. Binary compounds are selected from the group consisting of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and mixtures thereof (or multiple mixtures thereof). Ternary compounds are selected from the group consisting of CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, and HgS. Group III-V compounds may further include Group II metals (e.g., InZnP, etc.).

[0131] Group III-VI compounds may include: binary compounds (such as In2S3 and / or In2Se3); ternary compounds (such as InGaS3 and / or InGaSe3); or any combination thereof.

[0132] III-V group compounds can be selected from the group consisting of binary, ternary and quaternary compounds. Binary compounds are selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb and mixtures thereof. Ternary compounds are selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InAlP, InNP, InNAs, InNSb, InPAs, InPSb and mixtures thereof. Quaternary compounds are selected from the group consisting of GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb and mixtures thereof.

[0133] Group IV-VI compounds can be selected from the group consisting of binary, ternary, and quaternary compounds. Binary compounds are selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, and mixtures thereof. Ternary compounds are selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and mixtures thereof. Quaternary compounds are selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe, and mixtures thereof. Group IV elements can be selected from the group consisting of Si, Ge, and mixtures thereof. Group IV compounds can be binary compounds selected from the group consisting of SiC, SiGe, and mixtures thereof.

[0134] Group I-III-VI compounds may include ternary compounds (such as AgInS, AgInS2, CuInS, CuInS2, CuGaO2, AgGaO2, AgAlO2, or any combination thereof).

[0135] In this configuration, binary, ternary, and / or quaternary compounds can exist in the particles at a uniform concentration distribution, or they can exist in the same particle at partially different concentration distributions. In one or more embodiments, a core / shell structure can exist where one quantum dot surrounds another quantum dot. The interface between the core and shell can have a concentration gradient in which the concentration of the elements present in the shell decreases towards the center.

[0136] In one or more embodiments of the quantum dot (QD), the shell SL can be formed of a metal oxide, a non-metal oxide, a semiconductor compound, or a combination thereof. For example, the metal oxide or non-metal oxide can be: a binary compound (such as SiO2, Al2O3, TiO2, ZnO, MnO, Mn2O3, Mn3O4, CuO, FeO, Fe2O3, Fe3O4, CoO, Co3O4, and / or NiO); or a ternary compound (such as MgAl2O4, CoFe2O4, NiFe2O4, and / or CoMn2O4), but the embodiments of this disclosure are not limited thereto.

[0137] In one or more embodiments, the semiconductor compound may be, for example, CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, etc., but the embodiments disclosed herein are not limited thereto.

[0138] Quantum dot QDs can have a full width at half maximum (FWHM) of an emission wavelength spectrum of about 45 nm or less (e.g., about 40 nm or less, or about 30 nm or less), and can enhance color purity and / or color reproducibility within this range. In one or more embodiments, light emitted by such a quantum dot QD is emitted in all directions, thus improving wide viewing angles.

[0139] In one or more embodiments, although there is no specific limitation on the form of quantum dots (QDs) as long as it is a suitable form, quantum dots in the form of spherical, pyramidal, multi-armed and / or cubic nanoparticles, nanotubes, nanowires, nanofibers, nanoparticles, etc., can be used.

[0140] Quantum dot (QD) devices can control the color of emitted light based on their particle size, thus allowing them to emit various colors (such as blue, red, green, etc.). The smaller the particle size of a QD, the shorter the wavelength range of the emitted light. For example, in QDs with the same core, the particle size of the quantum dots emitting green light can be smaller than that of the quantum dots emitting red light. In one or more embodiments, in QDs with the same core, the particle size of the quantum dots emitting blue light can be smaller than that of the quantum dots emitting green light. However, the embodiments of this disclosure are not limited to these, and even in QDs with the same core, the particle size can be adjusted according to the shell thickness and the forming material.

[0141] When quantum dots (QDs) have various emission colors such as blue, red, and green, QDs with different emission colors can have different core materials.

[0142] In one or more embodiments, the ligand LD includes a head HD bound to the surface of the quantum dot QD and a tail TL exposed to the outside. The ligand LD may also include a chain CN connecting the head HD and the tail TL.

[0143] The head HD of the ligand LD is the portion bound to the surface of the quantum dot QD and may include functional groups bound to the surface of the quantum dot QD. The head HD may include hydrophilic groups, such as thiols, dithioates, phosphines, catechols, aminos, and / or carboxylic acids. When the head HD includes a single functional group bound to the surface of the quantum dot QD, the ligand LD may be a monodentate ligand. When the head HD includes two functional groups bound to the surface of the quantum dot QD, the ligand LD may be a bidentate ligand. The head HD may include functional groups from the surface of the shell SL of the quantum dot QD, thus allowing the ligand LD to bind efficiently (or appropriately) to the quantum dot QD.

[0144] The tail TL of the ligand LD can bind to a ligand bound to another quantum dot and includes a crosslinkable functional group at the end. There are no specific limitations on the crosslinkable functional group, as long as it is a functional group capable of forming a bond with another functional group, and it can be, for example, a thermally crosslinkable or photocrosslinkable functional group. In one or more embodiments, the crosslinkable functional group can be vinyl, hydroxyl, carboxyl, epoxy, amide, amino, azide, oxetyl, and / or isocyanate.

[0145] The chain portion CN of the ligand LD can connect the head HD and the tail TL, and adjust the length of the ligand LD to control the dispersibility of the quantum dot complex QD-C in the quantum dot composition QCP. For this purpose, the chain portion CN can include 2 to 20 carbon atoms. For example, it can include alkyl groups having 2 or more carbon atoms and alkyl groups having 1 or more carbon atoms, or it can include alkyl groups having 3 or more carbon atoms. When the number of carbon atoms in the chain portion CN is less than 2, the distance between the quantum dots QD may be too small (e.g., the quantum dots QD may be too close to each other), and when the number of carbon atoms is greater than 20, the distance between the quantum dots QD may be too large (e.g., the quantum dots QD may be too far apart). The chain portion CN can also include functional groups depending on the type (or kind) of organic solvent SV in which the quantum dot complex QD-C is dispersed, such as amino, oxygen, thio, ester, ether, aryl, and / or amide groups.

[0146] In one or more embodiments, the chain portion CN may be omitted, and the head HD and tail TL of the ligand LD may be directly connected.

[0147] In one or more embodiments, the ligand LD can be represented by formula A or formula B below.

[0148] Formula A

[0149] *-XY

[0150] Formula B

[0151]

[0152] In Equations A and B above, X, X1, and X2 can each be independently S or NH, and Y can be represented by at least one (or any one) of Equations 1 to 7 below. In this description, "*-" indicates a location connected to the quantum dot (e.g., a binding site with the quantum dot). However, embodiments of this disclosure are not limited thereto.

[0153] Formula 1

[0154]

[0155] Formula 2

[0156]

[0157] Formula 3

[0158]

[0159] Formula 4

[0160]

[0161] Formula 5

[0162]

[0163] Formula 6

[0164]

[0165] Formula 7

[0166]

[0167] In Formulas 1 to 7 above, R1 can be an alkyl group having 1 (e.g., 2) to 20 carbon atoms, and R2 can be an alkyl group having 1 to 20 carbon atoms, wherein the sum of the number of carbon atoms in R1 and R2 is 20 or less. In Formulas 1 to 7 above, Indicates the location to connect to Formula A or Formula B.

[0168] Figure 9 This is a schematic view illustrating the action (S200) of providing heat to form an emitting layer in a method for manufacturing a light-emitting element according to one or more embodiments. Figure 10This is a schematic view showing a cross-section of the correspondingly formed emission layer EML. Figure 11 Quantum dot compositions according to one or more embodiments are shown. Figure 12 It shows in Figure 11 Crosslinking reaction performed in quantum dot compositions.

[0169] According to one or more embodiments, providing heat to the pre-emitting layer P-EL can be performed by applying heat of 50°C or higher, 70°C or higher, or 100°C or higher to provide (e.g., promote) baking. The emitter layer of this disclosure can induce bonding between quantum dot complexes QD-C during baking for forming the emitter layer without requiring an additional process of providing heat for bonding between the quantum dot complexes QD-C. In one or more embodiments, baking can remove organic solvents such as SV included in the quantum dot composition QCP.

[0170] Reference Figure 10 The emitter layer (EML) comprises multiple quantum dot complexes QD-C1 and QD-C1-1 interconnected with each other. When heat is applied to the pre-emitter layer (P-EL), a crosslinking reaction occurs between ligand LD1, which is bound to quantum dot QD1 comprising a core CR1 and a shell SL1 surrounding the core CR1, and ligand LD1-1, which is bound to another quantum dot QD1-1 comprising a core CR1-1 and a shell SL1-1 surrounding the core CR1-1. Thus, ligands LD1 and LD1-1 can form bonds with each other. The tail of ligand LD1 includes a crosslinkable functional group, which binds to a crosslinkable functional group at the tail of ligand LD1-1 bound to another quantum dot QD1-1. Therefore, quantum dot complex QD-C1 can bind to other quantum dot complexes QD-C1-1.

[0171] exist Figure 10 In this embodiment, the quantum dot complex QD-C1 is exemplarily shown as being formed of approximately three layers, but the embodiments of this disclosure are not limited thereto. For example, the arrangement of the quantum dot complex QD-C1 can vary depending on the thickness of the emitter layer EML, the shape of the quantum dots QD1 included in the emitter layer EML, and the average diameter of the quantum dots QD1. For example, in the emitter layer EML, each of the quantum dot complexes QD-C1 can be bonded to at least two adjacent quantum dot complexes to form a single layer, or two or three layers can be formed.

[0172] like Figure 11 and Figure 12 As shown by way of example only, in the quantum dot complex QD-C1, a compound represented by formula C is bound to the quantum dot QD, and the shell SL comprises Zn.

[0173] Formula C

[0174]

[0175] In equation C above, R1 and R2 are the same as those defined in equations 1 to 7.

[0176] exist Figure 11 In this process, the head HD (thiol group) of the ligand LD binds to Zn (the metal ion contained in the shell SL), thus the ligand LD effectively (or appropriately) binds to the quantum dot QD, thereby forming a quantum dot complex. Quantum dot QDs can have bound ligand LDs to exhibit excellent dispersibility in organic solvents, even as inorganic particles.

[0177] Reference Figure 12 In baking, Figure 11 Quantum dot complexes can form bonds through a crosslinking reaction between the vinyl group of the first ligand LD1 bound to the first quantum dot QD1 and the vinyl group of the 1-1 (first-first) ligand LD1-1 bound to the adjacent 1-1 (first-first) quantum dot QD1-1. For example, quantum dot complexes can be positioned close to each other in the emitter layer through a crosslinking reaction between ligands LD1 and LD1-1.

[0178] Figure 13 This is a plan view of a display device DD according to one or more embodiments. Figure 14 This is a cross-sectional view of a display device DD according to one or more embodiments. Figure 14 It corresponds to Figure 13 A sectional view of line II-II'.

[0179] The display device DD of one or more embodiments may include a plurality of light-emitting elements ED-1, ED-2 and ED-3, and the light-emitting elements ED-1, ED-2 and ED-3 may respectively include emitting layers EML-B, EML-G and EML-R having quantum dot complexes QD-C1, QD-C2 and QD-C3 respectively.

[0180] In one or more embodiments, the display device DD of one or more embodiments may include a display panel DP comprising a plurality of light-emitting elements ED-1, ED-2 and ED-3 and a light control layer PP disposed on the display panel DP. In some embodiments, the light control layer PP may be omitted from the display device DD of one or more embodiments.

[0181] The display panel DP may include a substrate BS, a circuit layer DP-CL, and a display element layer DP-EL disposed on the substrate BS. The display element layer DP-EL may include a pixel defining film PDL, light-emitting elements ED-1, ED-2, and ED-3 disposed between portions of the pixel defining film PDL, and an encapsulation layer TFE disposed on the light-emitting elements ED-1, ED-2, and ED-3.

[0182] Reference Figure 13 and Figure 14 The display device DD may include a non-light-emitting region NPXA and light-emitting regions PXA-B, PXA-G, and PXA-R. Each of the light-emitting regions PXA-B, PXA-G, and PXA-R may be a region that emits light generated from each of the light-emitting elements ED-1, ED-2, and ED-3, respectively. The light-emitting regions PXA-B, PXA-G, and PXA-R may be spaced apart from each other on a plane.

[0183] The luminescent regions PXA-B, PXA-G, and PXA-R can be divided into multiple groups based on the color of the light emitted from the luminescent elements ED-1, ED-2, and ED-3. Figure 13 and Figure 14 In the display device DD of one or more embodiments shown, three light-emitting regions PXA-B, PXA-G, and PXA-R, respectively emitting blue, green, and red light, are exemplary. For example, the display device DD of one or more embodiments may include blue light-emitting region PXA-B, green light-emitting region PXA-G, and red light-emitting region PXA-R that are separated from each other.

[0184] Multiple light-emitting elements ED-1, ED-2, and ED-3 can emit light in different wavelength regions. For example, in one or more embodiments, the display device DD may include a first light-emitting element ED-1 that emits blue light, a second light-emitting element ED-2 that emits green light, and a third light-emitting element ED-3 that emits red light. However, the embodiments disclosed herein are not limited thereto, and the first light-emitting element ED-1, the second light-emitting element ED-2, and the third light-emitting element ED-3 may emit light in the same wavelength region, or emit light in at least one different wavelength region.

[0185] For example, the blue emitting area PXA-B, the green emitting area PXA-G, and the red emitting area PXA-R of the display device DD can correspond to the first emitting element ED-1, the second emitting element ED-2, and the third emitting element ED-3, respectively.

[0186] The first emitting layer EML-B of the first light-emitting element ED-1 may include a first quantum dot complex QD-C1. The first quantum dot complex QD-C1 can emit blue light as the first light.

[0187] The second emitting layer EML-G of the second light-emitting element ED-2 and the third emitting layer EML-R of the third light-emitting element ED-3 may respectively include a second quantum dot complex QD-C2 and a third quantum dot complex QD-C3. The second quantum dot complex QD-C2 and the third quantum dot complex QD-C3 may respectively emit green light as the second light and red light as the third light.

[0188] Each of the first quantum dot complex QD-C1, the second quantum dot complex QD-C2, and the third quantum dot complex QD-C3 may have a quantum dot and a ligand bound to the surface of the quantum dot. For example, in one or more embodiments, the first quantum dot complex QD-C1 may include a first quantum dot and a first ligand, the second quantum dot complex QD-C2 may include a second quantum dot and a second ligand, and the third quantum dot complex QD-C3 may include a third quantum dot and a third ligand. The description of the quantum dot complexes in the light-emitting element of one or more embodiments described above is equally applicable to each of the first quantum dot complex (multiple first quantum dot complexes) QD-C1, the second quantum dot complex (multiple second quantum dot complexes) QD-C2, and the third quantum dot complex (multiple third quantum dot complexes) QD-C3.

[0189] In one or more embodiments, the first quantum dot of the first quantum dot complex QD-C1, the second quantum dot of the second quantum dot complex QD-C2, and the third quantum dot of the third quantum dot complex QD-C3 included in the light-emitting elements ED-1, ED-2, and ED-3 may be formed from different core materials. In one or more embodiments, the first quantum dot of the first quantum dot complex QD-C1, the second quantum dot of the second quantum dot complex QD-C2, and the third quantum dot of the third quantum dot complex QD-C3 may be formed from the same core material, or two quantum dots selected from the first to the third quantum dots may be formed from the same core material, and the remaining quantum dots may be formed from different core materials.

[0190] In one or more embodiments, the first quantum dot of the first quantum dot complex QD-C1, the second quantum dot of the second quantum dot complex QD-C2, and the third quantum dot of the third quantum dot complex QD-C3 may have different diameters. For example, the first quantum dot used in the first light-emitting element ED-1 that emits light in a relatively short wavelength region may have a relatively smaller average diameter than the average diameter of the second quantum dot of the second light-emitting element ED-2 and the average diameter of the third quantum dot of the third light-emitting element ED-3 that emits light in a relatively long wavelength region. However, embodiments of this disclosure are not limited thereto, and the first to third quantum dots may be similar in size. In one or more embodiments, two quantum dots selected from the first to third quantum dots may have similar average diameters, and the remaining quantum dots may have different average diameters.

[0191] In one or more embodiments, the first ligand of the first quantum dot complex QD-C1, the second ligand of the second quantum dot complex QD-C2, and the third ligand of the third quantum dot complex QD-C3 may be the same as or different from each other. Based on the emission wavelengths of the light-emitting elements ED-1, ED-2, and ED-3, which respectively include the first quantum dot complex QD-C1, the second quantum dot complex QD-C2, and the third quantum dot complex QD-C3, the first to third ligands can be selected accordingly.

[0192] In one or more embodiments of the display device DD, such as Figure 13 and Figure 14 As shown, the areas of the luminescent regions PXA-B, PXA-G, and PXA-R can each be different from each other. In this case, the area can refer to the area when viewed on a plane defined by the first direction DR1 and the second direction DR2.

[0193] Depending on the colors emitted from the emitting layers EML-B, EML-G, and EML-R of the light-emitting elements ED-1, ED-2, and ED-3, the emitting regions PXA-B, PXA-G, and PXA-R can have different areas. For example, refer to... Figure 13 and Figure 14In the display device DD, the blue emitting region PXA-B corresponding to the first light-emitting element ED-1 that emits (used to emit) blue light can have the largest area, and the green emitting region PXA-G corresponding to the second light-emitting element ED-2 that generates (used to emit or generate) green light can have the smallest area. However, the embodiments of this disclosure are not limited to this, and the emitting regions PXA-B, PXA-G, and PXA-R can emit light other than blue, green, and red light, or the emitting regions PXA-B, PXA-G, and PXA-R can have the same area, or the emitting regions PXA-B, PXA-G, and PXA-R can have the same area as the first light-emitting element ED-1 that emits (used to emit) blue light. Figure 13 The area ratios shown are different area ratio settings.

[0194] Each of the luminescent regions PXA-B, PXA-G, and PXA-R can be a region separated by a pixel-defining film PDL. The non-luminescent region NPXA can be the region between adjacent luminescent regions PXA-B, PXA-G, and PXA-R, and can correspond to the pixel-defining film PDL. In this description, each of the luminescent regions PXA-B, PXA-G, and PXA-R can correspond to a pixel. The pixel-defining film PDL can separate luminescent elements ED-1, ED-2, and ED-3. The emitting layers EML-B, EML-G, and EML-R of luminescent elements ED-1, ED-2, and ED-3 can be disposed within openings OH defined by the pixel-defining film PDL, and therefore can be separated from each other.

[0195] Pixel-defining films (PDLs) can be formed from polymeric resins. For example, a pixel-defining film PDL can be formed comprising polyacrylate resins and / or polyimide resins. In one or more embodiments, in addition to polymeric resins, the pixel-defining film PDL can be formed by further comprising inorganic materials. In one or more embodiments, the pixel-defining film PDL can be formed comprising light-absorbing materials, or it can be formed comprising black pigments and / or black dyes. A pixel-defining film PDL formed comprising black pigments and / or black dyes can achieve a black pixel-defining film. Carbon black can be used as a black pigment and / or black dye when forming a pixel-defining film PDL, but embodiments of this disclosure are not limited thereto.

[0196] In one or more embodiments, the pixel-defining film (PDL) can be formed of an inorganic material. For example, the pixel-defining film (PDL) can be formed to include silicon nitride (SiN). x ), silicon dioxide (SiO) x ), silicon oxynitride (SiO) x N yPixel-defining film (PDL) can define the luminescent regions PXA-B, PXA-G, and PXA-R. The luminescent regions PXA-B, PXA-G, and PXA-R, as well as the non-luminescent region NPXA, can be separated by the pixel-defining film (PDL).

[0197] Each of the light-emitting elements ED-1, ED-2, and ED-3 may include a first electrode EL1, a hole transport region HTR, a corresponding emitter layer EML-B, EML-G, or EML-R, an electron transport region ETR, and a second electrode EL2. In the light-emitting elements ED-1, ED-2, and ED-3 included in a display device DD comprising one or more embodiments, the first quantum dot complex QD-C1, the second quantum dot complex QD-C2, and the third quantum dot complex QD-C3 included in the emitter layers EML-B, EML-G, and EML-R are different from each other, except that the combination... Figure 4 The provided description can also be applied to the first electrode EL1, the hole transport region HTR, the electron transport region ETR, and the second electrode EL2. In one or more embodiments, each of the light-emitting elements ED-1, ED-2, and ED-3 may further include a capping layer between the second electrode EL2 and the encapsulation layer TFE.

[0198] The encapsulation layer TFE can cover the light-emitting elements ED-1, ED-2, and ED-3. The encapsulation layer TFE can be a single layer or a stack of multiple layers. The encapsulation layer TFE can be a thin-film encapsulation layer. The encapsulation layer TFE protects the light-emitting elements ED-1, ED-2, and ED-3. The encapsulation layer TFE can cover the upper surface of the second electrode EL2 disposed in the opening OH, and can fill the opening OH.

[0199] Despite Figure 14 In the illustration, the hole transport region (HTR) and the electron transport region (ETR) are shown as a common layer simultaneously covering the pixel-defining film (PDL), but embodiments of this disclosure are not limited thereto. In one or more embodiments, the hole transport region (HTR) and the electron transport region (ETR) may be disposed within an opening (OH) defined by the pixel-defining film (PDL).

[0200] For example, when hole transport region HTR and electron transport region ETR are provided by inkjet printing in addition to emitter layers EML-B, EML-G, and EML-R, the hole transport region HTR, emitter layers EML-B, EML-G, and EML-R, and electron transport region ETR can be provided corresponding to the openings OH defined between portions of the pixel-defined film PDL. However, the embodiments are not limited to this, and as... Figure 14 As shown, the hole transport region (HTR) and electron transport region (ETR) can cover the pixel-defined film (PDL) without being patterned, and can be set as a common layer regardless of the method of providing each functional layer.

[0201] exist Figure 14 In the display device DD of one or more embodiments shown, although the thicknesses of the emitting layers EML-B, EML-G, and EML-R of the first light-emitting element ED-1, the second light-emitting element ED-2, and the third light-emitting element ED-3 are shown to be similar to each other, the embodiments are not limited thereto. For example, in one or more embodiments, the thicknesses of the emitting layers EML-B, EML-G, and EML-R of the first light-emitting element ED-1, the second light-emitting element ED-2, and the third light-emitting element ED-3 may be different from each other.

[0202] Reference Figure 13 Blue emitting regions PXA-B and red emitting regions PXA-R can be arranged alternately on the first direction DR1 to form a first group of PXG1. Green emitting regions PXA-G can be arranged on the first direction DR1 to form a second group of PXG2.

[0203] The first group of PXG1 and the second group of PXG2 can be spaced apart in the second direction DR2. Each of the first group of PXG1 and the second group of PXG2 can be configured as multiple. The first group of PXG1 and the second group of PXG2 can be arranged alternately in the second direction DR2.

[0204] A green emitting region PXA-G can be positioned on the fourth direction DR4, spaced apart from either a blue emitting region PXA-B or a red emitting region PXA-R. The fourth direction DR4 can be the direction between the first direction DR1 and the second direction DR2.

[0205] Figure 13 The arrangement of the light-emitting regions PXA-B, PXA-G, and PXA-R shown can have Structure or pattern ( (This is a registered trademark owned by Samsung Display Co., Ltd.). However, the arrangement of the light-emitting regions PXA-B, PXA-G, and PXA-R in the display device DD according to one or more embodiments is not limited to... Figure 13 The arrangement structure shown is illustrated. For example, in one or more embodiments, the light-emitting regions PXA-B, PXA-G, and PXA-R may have a striped structure (or pattern), wherein the blue light-emitting region PXA-B, the green light-emitting region PXA-G, and the red light-emitting region PXA-R may be arranged alternately along the first direction DR1.

[0206] Reference Figure 14One or more embodiments of the display device DD further include a light control layer PP. The light control layer PP can block or reduce external light incident on the display panel DP from outside the display device DD. The light control layer PP can block or reduce a portion of the external light. The light control layer PP can perform a reflection prevention (or reflection reduction) function to minimize (or reduce) reflections caused by external light.

[0207] exist Figure 14 In one or more embodiments shown, the light control layer PP may include a color filter layer CFL. For example, the display device DD in one or more embodiments may also include a color filter layer CFL disposed on the light-emitting elements ED-1, ED-2 and ED-3 of the display panel DP.

[0208] In a display device DD of one or more embodiments, the light control layer PP may include a substrate layer BL and a color filter layer CFL.

[0209] The substrate layer BL can be a component providing a substrate surface on which the color filter layer CFL is disposed. The substrate layer BL can be a glass substrate, a metal substrate, a plastic substrate, etc. However, the embodiments of this disclosure are not limited thereto, and the substrate layer BL can be an inorganic layer, an organic layer, or a composite material layer (e.g., including inorganic and organic materials).

[0210] A color filter layer (CFL) may include a light-blocking unit (BM) and color filters (CF). The color filters (CF) may include multiple filters (CF-B, CF-G, and CF-R). For example, the color filter layer (CFL) may include a first filter (CF-B) that transmits a first color of light, a second filter (CF-G) that transmits a second color of light, and a third filter (CF-R) that transmits a third color of light. For example, the first filter (CF-B) may be a blue filter, the second filter (CF-G) may be a green filter, and the third filter (CF-R) may be a red filter.

[0211] Each of filters CF-B, CF-G, and CF-R may include a polymeric photosensitive resin and a pigment and / or dye. The first filter CF-B may include a blue pigment and / or a blue dye, the second filter CF-G may include a green pigment and / or a green dye, and the third filter CF-R may include a red pigment and / or a red dye.

[0212] However, the embodiments disclosed herein are not limited thereto, and the first filter CF-B may not include pigments or dyes. The first filter CF-B may include a polymeric photosensitive resin, but not pigments or dyes. The first filter CF-B may be transparent. The first filter CF-B may be formed of a transparent photosensitive resin.

[0213] The light-blocking unit BM can be a black matrix. The light-blocking unit BM can be formed to include organic or inorganic light-blocking materials, both of which include black pigments and / or black dyes. The light-blocking unit BM can prevent or reduce light leakage and separate (e.g., define) the boundaries between adjacent filters CF-B, CF-G, and CF-R.

[0214] The color filter layer CFL may also include a buffer layer BFL. For example, the buffer layer BFL may be a protective layer for filters CF-B, CF-G, and CF-R. The buffer layer BFL may be an inorganic material layer comprising at least one inorganic material selected from silicon nitride, silicon oxide, and silicon oxynitride. The buffer layer BFL may be formed from a single layer or multiple layers.

[0215] exist Figure 14 In one or more embodiments shown, the first filter CF-B of the color filter layer CFL is shown stacked with the second filter CF-G and the third filter CF-R, but the embodiments of this disclosure are not limited thereto. For example, the first filter CF-B, the second filter CF-G, and the third filter CF-R may be separated by the light-blocking unit BM and may not be stacked with each other. In one or more embodiments, the first filter CF-B, the second filter CF-G, and the third filter CF-R may be configured to correspond to the blue emitting region PXA-B, the green emitting region PXA-G, and the red emitting region PXA-R, respectively.

[0216] In one or more embodiments, the display device DD may include a polarizing layer instead of a color filter layer CFL as a light control layer PP. The polarizing layer can block or reduce external light supplied to the display panel DP from the outside. The polarizing layer can block or reduce a portion of the external light.

[0217] In one or more embodiments, the polarization layer can reduce reflected light generated in the display panel DP by external light. For example, the polarization layer can function to block or reduce reflected light that is incident on the display panel DP from outside the display device DD and then re-ejected. The polarization layer can be a circular polarizer with reflection prevention (or reflection reduction) function, or the polarization layer can include a linear polarizer and a λ / 4 phase delayer. The polarization layer can be disposed on the substrate layer BL to be exposed, or the polarization layer can be disposed below the substrate layer BL.

[0218] Figure 15 This is a cross-sectional view of a display device DD-1 according to one or more other embodiments of the present disclosure. In the description of the display device DD-1 according to one or more embodiments, references to the above will not be further described. Figures 1 to 14 The descriptions overlap, and the main focus will be on the differences.

[0219] Reference Figure 15 In one or more embodiments, the display device DD-1 may include a light conversion layer CCL disposed on the display panel DP-1. In one or more embodiments, the display device DD-1 may also include a color filter layer CFL. The color filter layer CFL may be disposed between the substrate layer BL and the light conversion layer CCL.

[0220] Display panel DP-1 can be a light-emitting display panel. For example, display panel DP-1 can be an organic electroluminescent display panel or a quantum dot light-emitting display panel.

[0221] The display panel DP-1 may include a substrate BS, a circuit layer DP-CL disposed on the substrate BS, and a display element layer DP-EL1.

[0222] The display element layer DP-EL1 includes a light-emitting element ED-a, and the light-emitting element ED-a may include a first electrode EL1 and a second electrode EL2 facing each other, and multiple layers OL disposed between the first electrode EL1 and the second electrode EL2. The multiple layers OL may include a hole transport region HTR (Hole Transport Region). Figure 4 ), EML (Emitting Layer) Figure 4 ) and Electronic Transmission Zone (ETR) Figure 4 The TFE encapsulation layer can be placed on the light-emitting element ED-a.

[0223] In the light-emitting element ED-a, it can be compared with the reference. Figure 4 The same content described applies to the first electrode EL1, the hole transport region HTR, the electron transport region ETR, and the second electrode EL2. However, in one or more embodiments of the light-emitting element ED-a included in the display panel DP-1, the emitting layer may include a host and dopant as an organic electroluminescent material, or may include a reference... Figures 1 to 13 The quantum dot complex is described. In the display panel DP-1 of one or more embodiments, the light-emitting element ED-a can emit blue light.

[0224] The light conversion layer CCL may include a plurality of spacer walls BK disposed spaced apart from each other, and light control units CCP-B, CCP-G, and CCP-R disposed between the spacer walls BK. The spacer walls BK may be formed comprising a polymer resin and a coloring additive. The spacer walls BK may be formed comprising a light-absorbing material, or comprising pigments and / or dyes. For example, the spacer walls BK may comprise black pigments and / or black dyes to achieve black spacer walls. When forming black spacer walls, carbon black or the like can be used as the black pigment and / or black dye, but the embodiments of this disclosure are not limited thereto.

[0225] The light conversion layer (CCL) may include a first light control unit CCP-B that transmits a first light, a second light control unit CCP-G that converts the first light into a second light including a fourth quantum dot complex QD-C4, and a third light control unit CCP-R that converts the first light into a third light including a fifth quantum dot complex QD-C5. The second light may be light in a wavelength region longer than that of the first light, and the third light may also be light in a wavelength region longer than that of both the first and second light. For example, the first light may be blue light, the second light may be green light, and the third light may be red light. The quantum dot complexes (or multiple quantum dot complexes) QD-C4 and QD-C5 included in the light control units CCP-G and CCP-R can be applied to [specific applications]. Figure 14 The quantum dot complex used in the emission layer shown has the same content.

[0226] The light conversion layer CCL may also include a capping layer CPL. The capping layer CPL may be disposed on the light control units CCP-B, CCP-G, and CCP-R, as well as the partition wall BK. The capping layer CPL serves to prevent or reduce the penetration of moisture and / or oxygen (hereinafter referred to as "moisture / oxygen"). The capping layer CPL may be disposed on the light control units CCP-B, CCP-G, and CCP-R to prevent or reduce the exposure of the light control units CCP-B, CCP-G, and CCP-R to moisture / oxygen. The capping layer CPL may include at least one inorganic layer.

[0227] The display device DD-1 of one or more embodiments may include a color filter layer CFL disposed on the light conversion layer CCL, and Figure 14 The same description applies to the color filter layer CFL and the substrate layer BL.

[0228] Figure 16 This is a graph showing the electronic transition times of Examples 1 and 2, and Comparative Examples 1 and 2. Electronic transition time analysis was performed by measuring the relative changes in intensity using time-resolved photoluminescence. Example 1 is an evaluation of a quantum dot composition comprising quantum dots to which a ligand represented by Formula 5-1 is bound, and Example 2 is an evaluation of the emission layer formed by baking the quantum dot composition of Example 1. Comparative Example 1 is an evaluation of a quantum dot composition comprising quantum dots to which an oleic acid ligand represented by the comparative example formula is bound, and Comparative Example 2 is an evaluation of the emission layer formed by baking the quantum dot composition of Comparative Example 1. Except for the different ligands, the conditions for the examples and comparative examples are identical.

[0229] Formula 5-1

[0230]

[0231] Comparison Example

[0232]

[0233] In this disclosure, the electronic transition time refers to the time it takes for an electron to transition from an excited state to the ground state, and the lower the intensity during this time, the shorter the electronic transition time. (See also...) Figure 16 As can be seen, compared to Example 1 and Comparative Examples 1 and 2, Example 2 has the shortest electronic transition time over the entire time. Since the electronic transition time becomes shorter as the quantum dots are closer together, it is reasonable to assume that the quantum dots in Example 2 are closest together. Therefore, the quantum dot composition according to this disclosure includes crosslinkable functional groups at the tail end and can effectively (or suitably) bind to ligands bound to another quantum dot, thereby reducing the distance between quantum dots in the emission layer to increase the quantum dot stacking density and reduce space, thus improving luminescence efficiency can be expected.

[0234] The quantum dot composition according to one or more embodiments of the present disclosure includes a quantum dot complex in which ligands are bound to the surface of the quantum dots, and the ligands include crosslinkable functional groups in their tails to increase the dispersibility and end-capping properties of the quantum dot complex in the quantum dot composition, and exhibits excellent luminous efficiency when applied to a light-emitting element.

[0235] In related technologies, when ligands bind to the surface of quantum dots, the dispersibility and end-capping properties of the quantum dots in organic solvents can be improved. However, when applied to light-emitting elements, the ligands bound to the quantum dots suppress charge injection properties and may reduce the luminous efficiency of the light-emitting element. However, the quantum dot complexes according to one or more embodiments of this disclosure include crosslinkable functional groups at the tails of the ligands, and these functional groups undergo crosslinking reactions in the emitter layer, reducing the distance between the quantum dots. Therefore, the ligand-linked quantum dot complexes increase the stacking density of quantum dots in the emitter layer and reduce space, thus preventing or reducing the degradation of charge injection properties and improving the luminous efficiency of the light-emitting element.

[0236] Because the ligands bound to the surface of the quantum dots include charge-injection properties to prevent or reduce the degradation of charge-injection properties, the quantum dot compositions of one or more embodiments can be used as emission layer materials capable of exhibiting improved luminescence efficiency, even when applied to an emission layer.

[0237] One or more embodiments of the light-emitting element and display device may exhibit improved luminous efficiency and lifespan by including quantum dots that can prevent or reduce the degradation of charge injection properties in the emitting layer.

[0238] Although this disclosure has been described with reference to exemplary embodiments thereof, it will be understood that this disclosure should not be limited to these exemplary embodiments, but that various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of this disclosure.

[0239] Therefore, the scope of this disclosure is not intended to be limited to the specific embodiments described in the specification, but rather to be defined by the appended claims and their equivalents.

Claims

1. A quantum dot composition, said quantum dot composition comprising: quantum dots; as well as Ligands bind to the surface of the quantum dots. The ligand is represented by formula A or formula B: Formula A Formula B ， Among them, in equations A and B, X, X1, and X2 are all independently S or NH, and Y is represented by at least one of Equations 1 to 7: Formula 1 Formula 2 Formula 3 Formula 4 Formula 5 Formula 6 Formula 7 ， Among them, in equations 1 to 7, "indicates the position of attachment to Formula A or Formula B, and​ R1 and R2 are both independently alkyl groups having 1 to 20 carbon atoms, wherein the total number of carbon atoms in R1 and R2 is 20 or less, and " indicates a position connected to the quantum dot.​ 2. The quantum dot composition according to claim 1, wherein the quantum dot composition further comprises an organic solvent. wherein, The quantum dots are dispersed in the organic solvent.

3. The quantum dot composition according to claim 1, wherein, The quantum dot is a semiconductor nanocrystal comprising a core and a shell surrounding the core.

4. A light-emitting element, the light-emitting element comprising: First electrode; The second electrode faces the first electrode; as well as An emission layer, located between the first electrode and the second electrode, comprises a plurality of quantum dot complexes, each of which is a quantum dot composition according to claim 1. In this embodiment, one of the multiple quantum dot complexes binds to at least two other quantum dot complexes via the ligand.

5. The light-emitting element according to claim 4, wherein, The quantum dot has a core and a shell surrounding the core.

6. A display device, the display device comprising: Multiple light-emitting elements; as well as A light conversion layer is provided on the plurality of light-emitting elements. The light conversion layer includes a light control unit, which comprises a plurality of quantum dot compositions according to claim 1, wherein the plurality of quantum dots of the plurality of quantum dot compositions are interconnected by binding of the ligands. Each of the plurality of light-emitting elements includes a first electrode, a second electrode facing the first electrode, and an emitting layer between the first electrode and the second electrode.

7. The display device according to claim 6, wherein, The plurality of light-emitting elements emit light of a first color, and The light control unit includes: a first light control unit that transmits the first color light; a second light control unit that converts the first color light into a second color light; and a third light control unit that converts the first color light into a third color light.

8. The display device according to claim 7, further comprising a color filter layer on the plurality of light-emitting elements, in, The color filter layer includes: a first filter that transmits the first color light; a second filter that transmits the second color light; and a third filter that transmits the third color light.

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